JP4559097B2 - Image forming apparatus - Google Patents

Description

The present invention is a copying machine, a laser printer, using the facsimile and an electrophotographic method such as a complex machine thereof relates to an image forming equipment for forming an image.

  Desktop type or floor type image forming apparatus using indirect electrophotographic method (zero graph method) such as facsimile, laser printer, electrophotographic copying machine and their combined machines widely used as an apparatus for image formation In general, an electrophotographic photosensitive member as an image carrier, a charging device, an image exposure device, a developing device, a transfer device, a separating device, a cleaning device, a static eliminating device, a fixing device, and a paper feed tray for paper (transferred material) And a paper discharge tray. Hereinafter, the electrophotographic photoreceptor is simply referred to as a photoreceptor.

  The image formation in the image forming apparatus will be briefly described below. In the image forming apparatus, a charging device for forming an electrostatic latent image on the photoconductor is disposed oppositely. The photoconductor is formed by forming a photoconductive layer on a conductive support to generate carriers (holes and electrons) by injection of light (monochromatic light such as visible light, infrared light, or ultraviolet light). The total film thickness of the photosensitive layer is set to a film thickness of 10 to 50 (μm) in order to secure a sufficient potential necessary for image formation. The photosensitive member is uniformly charged by a charging device so that it becomes about (−) 400 to 800 (V) in the dark.

  The charging method includes a contact charging method, a corona charging method, a non-contact charging method (or a proximity charging method) in which a charging member is arranged at a distance of several tens of μm from the photosensitive member, and the charging member has a DC voltage or A DC voltage superimposed with an AC voltage is applied.

  As a photoreceptor used for image formation, there are a positively charged photoreceptor and a negatively charged photoreceptor. In the present invention, a function-separated organic photoreceptor composed of a charge generation layer and a charge transport layer is mainly used. Therefore, the charge polarity is negatively charged.

  When charging is completed, the photosensitive member is subjected to image exposure to form an electrostatic latent image. Image exposure uses an image exposure device that consists of a CCD (charge coupled device), polygon mirror, filter, light source (LD device or LED device), etc. The photosensitive member is irradiated with a light image converted into a pattern.

  By image exposure, a charge pattern (electrostatic latent image) corresponding to the input signal is formed on the photoreceptor. The electrostatic latent image is reversely developed by a developing device (usually the magnet brush method is generally used) in which a two-component developer composed of toner and carrier is introduced, and is visualized as a toner image on the photosensitive member. (Reverse image).

  The toner image is transferred to a sheet as a transfer medium conveyed from a paper feed tray using a transfer device to which a voltage opposite to the toner charging polarity is applied, and is transferred to a fixing device after transfer and fixed. As a result, the hard copy is made and then discharged to a paper discharge tray.

  The toner image remaining on the photoconductor after the transfer is cleaned as a residual powder by a cleaning device, and then the entire surface of the photoconductor is irradiated with light, the internal latent image is neutralized, electrically initialized, and a series of The copying cycle ends.

By the way, the photoreceptor used for image formation includes a zinc oxide photoreceptor (ZnO), a cadmium sulfide photoreceptor (CdS), a cadmium selenide photoreceptor (CdSe), and an amorphous selenium photoreceptor (for example, a-Se). , A-Se-Te, a-As ₂ Se ₃ etc.), amorphous silicon photoconductors (for example, a-SiH, a-Si: Ge: H), etc. Although it is manufactured as a highly durable photoconductor, on the other hand, it is easy to manufacture, high-sensitivity design is possible, and the conversion to organic photoconductors with many advantages such as low cost and pollution-free progresses, and the digital age In response, the development of digital photoconductors with higher sensitivity and durability that match the digital system is also underway.

  The structure of the organic photoreceptor includes a function-separated type photoreceptor composed of two layers of a charge generation layer and a charge transport layer on a conductive support, and a single layer configuration in which the charge generation material and the charge transport material are integrated. Although there are advantages and disadvantages of each, there are advantages and disadvantages, but the function-separated type photoconductor is excellent in terms of mechanical durability and superiority in design, etc. Yes.

  The basic structure of the function-separated type photoconductor is that an undercoat layer of 1 to 20 μm, a charge generation layer of 0.1 to 2 μm, and a charge transport layer of 10 to 50 μm are sequentially laminated on a conductive support such as aluminum. In addition, by configuring the charge transport layer as the uppermost layer of the photoreceptor, the degree of freedom in design with respect to mechanical durability is expanded. For the charge transport layer, a resin such as an amorphous / polyolefin resin (APO), a polystyrene resin (PS), a polycarbonate resin (PC) such as A-type, C-type, or Z-type is used as a binder resin.

  The durable number of photoconductors using a binder resin is about 40,000 to 80,000 in the case of A-4 size lateral feed in the market results, and it is suitable for inorganic photoconductors such as a-Si photoconductor and selenium. Although it is inferior in durability, if the photoconductor is not damaged by paper jam or the like, it is a durable sheet that is generally free from problems.

  The number of durable sheets depends on the abrasion of the photosensitive layer, scratches, damage caused by dents and electric discharge destruction, chemical degradation due to the tentacles and corona products during charging, etc. It is the number of sheets when they are naturally worn without being affected. The range of the number of durable sheets is considered to be caused by the type of material used and the image forming conditions (for example, contrast potential, toner concentration, cleaning blade contact pressure, document image area, etc.).

  The endurance number of 40,000 to 80,000 is not particularly deficient in normal use, but a user with a large number of copies needs to frequently replace the photoconductor. In addition, with the introduction of computers, the number of copies has steadily increased rather than decreasing, and with the promotion of maintenance-free, the higher durability of photoconductors has become increasingly important.

Wear of the photoreceptor is caused by a member that is in sliding contact with the photoreceptor, such as a developer, a cleaning blade, a cleaning brush, or a contact charging member. Indirect factors include the action of corona products such as ozone and NOx generated during charging.
In addition to optimizing the amount of developer, contact pressure of the cleaning blade, reducing ozone and NOx, etc., the wear resistance of the outermost surface of the photoconductor or the entire photosensitive layer can be suppressed by these factors. It can be improved by taking measures to increase the property and scratch resistance. In particular, by increasing the hardness of the outermost surface layer of the photoreceptor, it is possible to improve durability several times. Specific means for improving the wear resistance of the photoreceptor include a material having high wear resistance in the photosensitive layer (for example, a method in which fine particles having high hardness such as silica and alumina are contained in the resin, and light or heat in the resin layer. In addition to the method of using a curable cross-linked resin, it is possible to reduce the coefficient of friction (or surface free energy) on the surface of the photosensitive layer.

  Since the photosensitive layer of the organic photoreceptor is low in hardness, in addition to damage due to wear, the photosensitive layer is likely to be depressed, or fine rubbing scratches and deep groove scratches are easily formed. In particular, photoconductors with low hardness are affected at the same time as the start of copying or during idling, and photoconductors with high hardness are also affected by the hardness of the photoconductor. appear. The main factor for the occurrence of the rubbing scratch is rubbing with a cleaning blade, a developer, a contact charging member or the like, but since such rubbing scratch is shallow, the image is hardly affected.

  However, the carrier away from the developing sleeve, the talc adhering to the paper, the toner agglomerates, the shape that was rarely removed sufficiently by washing was indeterminate from the image forming apparatus main body side When hard foreign matter such as iron fine particles (cutting scraps) is sandwiched between the cleaning blade and the photosensitive member and / or the transfer member and the photosensitive member, scratches such as dents and scratches appear to be dragged. It appears on the copy as black streaks.

  Deep scratches that reach the conductive support (support layer) of the photoconductor, such as a dent, can be obtained by charging the black streaks at the hole positions even when the contact charging member is used. Along the line. In the case of a scratch, the background portion of the image often has black streaks, and the solid image often has white streaks depending on the potential level. In particular, since the carrier has a large particle size of around 60 μm and extremely high hardness, it tends to scratch when pressed with a cleaning blade.

  The two-component developer is composed of magnetic powder called a carrier and toner, and the developer is always in contact with the photoconductor as well as during development. Therefore, when the charged potential of the photosensitive member is too high, the carrier diameter is small, the developer spikes in the developing device are long, or the magnetic force of the magnet constituting the developing device is weak, the developer is on the photosensitive member. When an adhesion factor occurs, the carrier adheres to the photosensitive member electrostatically or physically, passes through the transfer device, and is conveyed to the cleaning device.

  The cleaning blade is arranged to clean the toner on the photoconductor. However, when hard particles such as a carrier adhere to the photoconductor and the carrier enters between the blade and the photoconductor, the blade is pressed by the blade. For this reason, abnormal images and scratches that shorten the life of the photosensitive member and the cleaning blade are formed. That is, when the carrier adheres to the photoconductor, when the toner image is transferred to the transfer target (paper, OHP sheet, etc.), the photoconductor is depressed by the transfer belt or transfer roller, and the cleaning blade When the sheet is conveyed to the position, it is pressed by a cleaning blade, and deeper scratches are formed.

  When pressed against the photoconductor with a blade, the fine particles will bite into the photoconductor, resulting in dents, scratches, and scratches, resulting in black streaks and background stains in terms of image quality, and numerous indentations and deep scratches on the photoconductor and cleaning blade. It causes fatal defects and is forced to be replaced. Scratches are scratches caused by hard fine powders such as carriers and fillers, even if they do not appear in the image. These scratches are relatively deep scratches of 10 μm or more, and scratches are scars made of a rubbing member such as a blade. It refers to a relatively shallow scratch of about several microns. It is a sensory distinction.

  The load (pressing) of the blade against the photoreceptor is not limited to the present invention, and is usually set in the range of 15 to 30 g / cm. However, in the case of a spherical toner having a large average circularity, the toner is shaped like a sphere, so it is easy to sink under the curled blade by being pressed and pulled in the direction of rotation of the photosensitive member. Therefore, the load may be set to 30 g / cm or more. That is, the reason for applying the load is to prevent the formation of a gap that does not allow toner to enter between the photosensitive member and the cleaning blade.

  When the contact pressure of the cleaning blade is increased, the blocking rate of not only the toner but also the carrier with the cleaning blade is increased. However, since the wear of the edges of the photosensitive member and the cleaning blade proceeds, the durability is shortened. On the other hand, when hard particles such as a carrier have entered between the cleaning blade and the photosensitive member, the photosensitive layer in the part where the carrier enters may be recessed, or the photosensitive layer may be greatly scraped to cause deep scratches. If the phenomenon occurs repeatedly, the damage spreads throughout. If the scratch depth stays at a relatively shallow part of the photosensitive layer, the image hardly reveals as an abnormal image, but if the scratch layer enters the conductive layer, it is almost certain. It appears on the image as black streaks or black bands in the image. This also increases the possibility of missing parts on the cleaning blade. In some cases, toner cleaning failure may occur. Therefore, the photoconductor is forced to be replaced, and the cleaning blade needs to be replaced depending on the situation.

  As described above, when the carrier sinks between the blade and the photosensitive member, scratches are generated on the photosensitive member until the carrier comes out, but the blade edge is also damaged by the pressure contact. Note that corona products generated during charging, particularly NOx, cause the blade to deform and become hard, which causes defects. Although damage to the edge of the cleaning blade may cause cleaning failure, the photoconductor may be further damaged when sharp damage or a blade with high hardness is used.

  In the case of a photoconductor with low hardness, if the photoconductor is used as it is, the entire photosensitive layer is worn, and even if black streaks or black spots occur, it becomes gradually less visible and may disappear naturally. However, in the case of a photoreceptor with improved wear resistance, wear is slow, and once a scratch is made, the scar remains forever, so an abnormal image is not easily improved. When such a state is reached, it is necessary to replace the photoreceptor or both the photoreceptor and the cleaning blade. Therefore, it is important to remove the carrier before reaching the cleaning blade in order to maintain the photoreceptor in a good state for a long time.

  The adhesion of the carrier to the photosensitive member increases as the particle size becomes smaller. Even when the carrier has a large particle size of 80 μm to 100 μm, if the charging potential is high or the potential difference between the charging potential and the developing bias is large, the magnetic flux density of the developing portion Is low, the carrier tends to transfer to the photoreceptor more easily than the developing sleeve, for example, when the development spikes are large.

  In this way, hard fine particles such as carriers adhering to the photoconductor greatly affect not only the photoconductor but also the cleaning blade. Therefore, the fine particles adhering to the photoconductor are not affected (for example, cleaning) It is important to remove them before they reach the blade.

  In the image forming apparatus, a method in which the carrier is not attached to the photoconductor is also implemented, but even if it is temporarily effective, it is not sufficient. In this respect, since the carrier is magnetic powder, a method using a magnet is a general and reliable method, and many examples have been disclosed. Examples thereof are disclosed below.

  Patent Document 1 and Patent Document 2 describe that a magnet is disposed between a developing device and a transfer device or / and between a transfer device and a cleaning device to remove the carrier immediately before the cleaning device. Yes. When the amount of the carrier attached to the photoconductor is small, it is an effective means for eliminating the electrostatically attached carrier. Even if even a little remains without being removed, there is almost no problem as long as the cleaning blade functions sufficiently.

  In Patent Document 3, a magnetic attraction means is arranged behind the cleaning brush, the carrier is knocked off from the photosensitive member with a rotating cleaning brush, the carrier adhering to the cleaning brush is knocked off with a flicker bar, and the carrier is sucked with a magnet. The contents to be excluded are described.

  Patent Document 4 describes a configuration in which a carrier attached to the photosensitive member is removed by providing a yoke on the downstream side of the developing device and attaching a carrier cleaner with increased magnetic field lines. This method is a dedicated device for removing the carrier adhering to the photoconductor. Since the magnet is mounted in the non-magnetic rotating sleeve, the carrier adhering on the sleeve also rotates the carrier by rotating the sleeve. Moves and is eliminated. Therefore, it is excellent in that it does not reattach to the photoreceptor.

  On the other hand, as described above, a cleaning blade is often used as a main removal member for cleaning residual powder remaining on the photosensitive member such as toner. As described above, the cleaning blade has a risk of causing significant damage when the carrier adheres to the photosensitive member. However, the cleaning blade is indispensable for the image forming apparatus to guarantee good image forming performance. It is an important member.

  The electrostatic latent image is developed and visualized as a toner image, and then transferred to a transfer medium such as plain paper or an OHP film by a transfer device. Since the transfer efficiency of a normal toner image is usually about 93 to 98%, the toner remains on the photoreceptor. For this purpose, a cleaning means is required, and a cleaning blade is used as the means. Since the cleaning blade method can be designed compactly and has relatively good cleaning properties, it is widely used from small devices to large-scale mass copying devices.

  There are elastic members such as neoprene rubber, chloroprene rubber, silicone rubber, and acrylic rubber as the material of the cleaning blade, but they do not cause chemical damage to the photoreceptor, and have excellent characteristics such as durability, ozone resistance, and oil resistance. The polyurethane rubber (or urethane rubber) is preferable. The cleaning blade used in the cleaning device is generally a blade that is cut into a strip shape and fixed on one side of the support, and the edge of the blade is abutted so as to bite as the photoconductor rotates. It is often installed by the method.

  The cleaning performance of residual powder composed of toner, paper dust, etc. is the surface roughness of the photoconductor and the cleaning blade, the coefficient of friction of the photoconductor, the frictional resistance between the photoconductor and the cleaning blade, the hardness and elongation of the cleaning blade. It depends on. The edge of the cleaning blade has a surface roughness of about 10 μm. Cleaning blades wear and chip with use. The surface roughness of the cleaning blade is related to the cleaning properties of the toner, so it is desirable that the surface be as small as possible. However, if the surface roughness is too small, the adhesion to the photoconductor increases and the frictional resistance with the photoconductor increases. It is not preferable. When the coefficient of friction of the photosensitive member increases, the frictional resistance between the photosensitive member and the cleaning blade increases and the frictional force of the blade increases, so that the photosensitive layer is easily scratched.

  For this reason, abrasion of the photosensitive layer is promoted, and the durability of the photosensitive member and the cleaning blade is lowered, and at the same time, an opportunity to form a gap with the cleaning blade is provided. Further, when the friction coefficient is increased, vibration and distortion are generated, and furthermore, a stick-slip phenomenon is likely to occur, so that a minute gap is generated between the photosensitive member and the edge of the blade. The toner that has entered the gap becomes a so-called cleaning defect that escapes to the charging device side. If this phenomenon continues, it causes image quality background stains, contamination of the charging member, and deterioration of durability due to increased wear of the cleaning blade and the photosensitive member. In addition, the toner is pressed by a charging member, a cleaning blade, or the like, resulting in a filming phenomenon that adheres to the photosensitive member, and further causes an increase in frictional resistance.

  Therefore, it is necessary to make the edges contact evenly so that no gap is generated not only when the blade edge is stopped but also when the photosensitive member is in operation. If there is a gap between the photoconductor and the blade during the stop (for example, release), the toner or carrier adhering to the cleaning blade will enter, and the cleaning blade will not be able to contact the photoconductor completely at startup. There is a possibility that the photosensitive member may be damaged due to the foreign matter that has entered the blade. Further, it is also necessary for the photoreceptor to always have a friction coefficient within a suitable range so that the blade is not distorted and the stick-slip phenomenon does not occur.

  In recent years, polymerized toners have been used in response to the demand for higher image quality, but polymerized toners are almost spherical, so they have poor cleaning compared to irregularly pulverized toners with many irregularities that are still in use today. It tends to occur easily. This poor cleaning is caused by the shape of the toner. In the case of the polymerized toner, the shape is almost like a sphere, so there is no catch. Therefore, it is estimated that the damming at the blade edge becomes insufficient, and even if the gap is narrower than the toner diameter, the toner is pulled out while being submerged under the blade while rotating.

In order not to cause a cleaning failure, it is important to tightly seal the opportunity to form a gap between the photoreceptor and the cleaning blade.
As described above, the blade type cleaning device is often used because it has both cleaning performance and compactness. As soon as it is replaced with toner, it is often experienced that a cleaning failure occurs or a cleaning failure occurs during use, which is also a problem in the market.

  The cleaning blade is installed so that the edge is sufficiently in contact with the photoconductor. However, the blade edge is locally localized due to vibration accompanying the rotation of the photoconductor, insufficient hardness of the blade, slight distortion of the rubber blade itself, etc. It has been confirmed that the toner floats from the photoreceptor and causes toner loss. Therefore, improving the factor that eliminates the above-mentioned cleaning failure is a shortcut for improving the cleaning failure.

As the cleaning blade wears, the toner is sandwiched between the photoreceptor and the cleaning blade to reduce frictional resistance, but also promotes wear of the cleaning blade edge. Therefore, since cleaning defects are likely to occur, it is desirable to reduce the amount so that the frictional resistance between the cleaning blade and the photosensitive member does not increase in order to reduce the burden on the cleaning blade.
There are several methods for preventing poor cleaning. Examples of disclosure of typical patent documents are shown below. In Patent Document 5, the cleaning blade having a JIS-A hardness of 60 to 75 degrees is set to 25 to 60 (gf / cm), which is higher than a general contact pressure, and the adhesion to the photosensitive member is improved. The cleaning is performed so as not to cause the float. In the case of a spherical toner, it is easy to sink under the cleaning blade. Therefore, it is considered that increasing the adhesion between the photosensitive member and the blade increases the possibility of preventing defective cleaning. That is, in Patent Document 5, the contact pressure is set higher than when pulverized toner is used to prevent poor cleaning. By increasing the contact pressure, even if the blade edge is distorted or has some unevenness, a gap is less likely to be generated, and defective cleaning can be improved.

  In Patent Document 6, by applying minute vibration to the edge portion of the cleaning blade, scraping powder such as a photoconductor accumulated (aggregated) on the blade edge portion is removed to prevent the blade from floating. It is described that toner is sufficiently adhered to a photoreceptor to improve toner cleaning failure. This system is intended to improve the cleaning property by removing the toner adhering to the cleaning blade and the toner adhering to the photosensitive member.

  In Patent Document 7, a cleaning blade is made of a conductive material, and a ground or voltage (AC voltage or DC voltage) is applied to remove the charge held in the toner, thereby improving separation of the toner from the photoreceptor and the cleaning blade. Thus, the cleaning performance of the small particle size toner and the polymerization toner is improved.

  The following patent document describes that a cleaning blade is mechanically reinforced to prevent toner cleaning failure.

  Patent Document 8 uses an organic photoreceptor made of a polycarbonate resin having a specific structure, and sets the linear pressure of the blade to 8 g / cm or more and 20 g / cm or less, and the pressure contact angle to 12 ° or more and 30 ° or less. Therefore, there is little wear, so that problems such as blade turning and blade squealing do not occur.

  According to Patent Document 9, in a cleaning blade, a damping material is attached to a part of the cleaning blade or a support so that the cleaning blade does not vibrate, thereby preventing toner from being removed and improving poor cleaning. The technology to do is described. In such a configuration, in the case of the polymerized toner, it is easy to come off if there is a slight gap. Therefore, it is important to eliminate the vibration of the cleaning blade and to ensure that the blade edge contacts the photoconductor. Suppressing the vibration of the cleaning blade is to make no gap between the photosensitive member and the cleaning blade, which seems to be reasonable.

  In Patent Document 10, a cleaning blade is attached to a support of a cleaning blade via an elastic member, and a relationship of 0.1B <A is established between the rebound resilience B of the elastic member and the rebound resilience A of the cleaning blade. Describes a technique that suppresses vibration of the cleaning blade, maintains a strong and stable cleaning force over a long period of time, and can also clean a spherical toner such as a polymerized toner.

Due to the shape of the spherical toner, the initial state is good, but the blade is damaged, the photoconductor is scratched, and immediately after the friction coefficient is increased, a gap is formed between the photoconductor and the cleaning blade. It tends to occur. In addition, even if the blade side is reinforced, if the entire cleaning member tends to vibrate, the effect of the reinforcement cannot be fully utilized, and it has been confirmed that cleaning failure will gradually occur during use. .
When using spherical toner, it is important to prevent the cleaning member from moving finely, and it is possible not only to prevent vibration but also to prevent defective cleaning, as well as the cleaning blade edge. Therefore, the life of the cleaning blade as a member can be extended.

  In Patent Document 11, a rigidity reinforcing member for reinforcing the cleaning blade is provided on the opposite side of the support with the cleaning blade interposed therebetween, and is disposed on the downstream side in the rotation direction of the image carrier, thereby causing a difference in environment. It describes that cleaning defects (occurrence of white spots) are avoided. This means attaches a reinforcing member (a thin plate of ABS resin, polycarbonate resin or the like) to the side surface of the cleaning blade and avoids elastic deformation of the cleaning blade when it is in contact with the image carrier and operated. Is.

  When the image carrier, that is, the photoconductor rotates, if there is a part with a large frictional resistance between the photoconductor and the cleaning blade, the cleaning blade is locally distorted by the tip of the cleaning blade being dragged in the rotation direction of the photoconductor. This occurs because a gap is formed. That is, the contents described in Patent Document 11 are effective means for preventing the blade from being distorted.

Japanese Patent Laid-Open No. 6-035372 JP-A-6-124024 JP-A-5-107989 JP 10-116007 A JP-A-6-318022 JP 2003-43893 A JP-A-7-210053 JP 2002-268491 A JP 2002-196642 A JP 2001-242758 A JP-A-10-111628

  In Patent Documents 1 and 2, if a large amount of toner remains without being transferred onto the photoreceptor, and the electrostatic force of the photoreceptor is strong, it is not easy to suck the carrier. Also, if there is a scratch on the photoconductor or a defect in the cleaning blade, or if the cleaning blade further vibrates, a stick-slip phenomenon will occur, and the cleaning blade may float off the photoconductor for a moment, When the blade in a state where the blade is in contact with the photoconductor has a gentle curve, the carrier is likely to be sandwiched between the photoconductor and the possibility of biting into the photoconductor is increased. In particular, when the carrier is transported frequently, the removal cannot be separated by the magnet, so that a large amount of carrier exists on the photosensitive member, and the possibility of being damaged by the cleaning blade is increased.

  Even if the carrier transport amount is small, if a large amount of carrier accumulates in the magnet during long-term image formation, the surface potential of the photoconductor is high, electrostatic attraction is superior, or minute toner adheres In this case, the problem that the attached carrier contacts the photoreceptor and reattachment to the photoreceptor cannot be ignored. If there is a cleaning blade defect or a stick-slip phenomenon, there is a risk of damaging the photoreceptor. .

  In the configuration of Patent Document 3, since the carrier adhering to the photosensitive member is forcibly tapped off, an effect is recognized, but since the cleaning brush is used, the carrier easily enters the brush, Since the carrier that has entered the back of the brush is separated from the magnet and contains a large amount of toner, the magnetic force is difficult to reach. For this reason, the carrier cannot be easily removed, and even when the carrier does not adhere to the photoconductor, even if the carrier held in the brush pops out and the carrier does not adhere to the photoconductor, it is always harmful. Have the potential to give

  In the configuration of Patent Document 4, since the magnet does not rotate, a part of the carrier may remain on the sleeve (near the edge of the magnet), and the accumulated carrier extends the ear and re-appears on the photoreceptor. There are concerns about adhesion and there is a need for improvement. In addition, an installation space is required, and installation may be difficult in a small image forming apparatus.

  As explained above, the means to remove the carrier using a magnet is a method that has been achieved. However, depending on the treatment of the carrier attached to the magnet, it may reattach to the photoconductor and cause an unexpected adverse effect. Also have. Thus, although the method using a magnet has certainty, there is still room for improvement.

  In the configuration of Patent Document 5, when the coefficient of friction of the photosensitive member increases to 0.5 or 0.6 (numerical value measured by the Euler belt method), the malfunction caused by increasing the contact pressure is caused by the cleaning blade and the photosensitive member. Appear on both sides. That is, by increasing the contact pressure, the frictional resistance between the photoconductor and the cleaning blade increases, so that the photoconductor and the cleaning blade are likely to be worn away, or the rubbing sound with high frequency between the photoconductor and the cleaning blade is generated. And problems such as unstable rotation of the photosensitive member occur. Further, since the frictional resistance with the blade is increased, a load is applied to the blade edge, and the edge is easily distorted. That is, the cleaning performance of the toner temporarily increases, but the cleaning performance is difficult to maintain. Further, since there is no specification of the friction coefficient and no description of the lubricant in the text, it is presumed that the surface friction coefficient of the photoreceptor is high. When the frictional resistance is high, local distortion of the blade edge is likely to occur as described above, increasing the chance of defective cleaning, reducing the durability of the photoreceptor and the cleaning blade, and consequently affecting the image quality.

  In the configuration of Patent Document 6, although an effect is surely recognized in the initial stage, the toner is likely to be sandwiched between the cleaning blade and the photosensitive member due to vibration, and a tendency to cause a cleaning failure gradually is seen, and the effect is insufficient.

  In the configuration of Patent Document 7, the effect of static elimination is recognized for the toner that is in direct contact with the cleaning blade. However, since most of the toner is difficult to be neutralized, the effect is not as good as expected. However, the neutralization effect is extremely low, the efficiency of the cleaning performance is hardly improved, and the cleaning failure cannot be improved.

  In the configuration of Patent Document 8, it is considered reasonable to reduce the frequency of blade edge reversal by reducing the contact pressure and reducing the pressure contact angle. Also, the free length of the blade, which represents the unfixed area from the tip of the support to the contact with the photoreceptor, and the friction coefficient on the photoreceptor (or the frictional resistance between the blade and the photoreceptor) There is a close causal relationship between blade reversal frequency and blade squeal. In Patent Document 8, there is no definition of hardness (for example, JIS-A hardness by measurement according to JIS K 6301) and the length of the free length is not specified, so the effect is uncertain. In addition, since the corona product is attached due to electrification in the process of using the photoconductor, even if it is a polycarbonate resin having a siloxane structure, the effect is only in the initial stage, and the photoconductor gradually increases as it is used. The coefficient of friction of the surface increases, and problems such as blade reversal and blade squeal emerge. When the cleaning blade is brought into contact with the photosensitive member, it is desirable to set the contact pressure and angle so that the contact area of the blade edge is as small as possible. It is thought that it is hard to be done.

  In the configuration of Patent Document 9, vibration such as chatter due to sliding between the photosensitive member and the cleaning blade is effective when the support is as thin as 1 mm or less, but the vibration is stopped when the support is as thick as 2 mm or 3 mm. If the friction coefficient increases to about 0.5 or 0.6 due to adhesion of the corona product, filming on the surface of the photoconductor becomes difficult, even if it does not occur, the vibration of the cleaning blade increases. Since a phenomenon such as stick-slip occurs, it is difficult to obtain an improvement effect using only the damping material.

In the method described in Patent Document 10, it is considered that the effect of suppressing vibration is higher than that described in Patent Document 9, but when a small amount of distortion or gap occurs locally in a spherical toner, the toner is more likely to be generated from that portion. Omission occurs. Therefore, it is desirable that the blade edge is in contact with the photosensitive member evenly. However, in the method of inserting an elastic member between the support and the cleaning blade, the blade edge cannot be managed, so that cleaning failure is prevented. It cannot be resolved. In addition, by interposing the elastic member, when the photosensitive member is brought into contact with the blade, the blade is displaced, and the contact pressure of the cleaning blade is substantially lighter than the set value, so that toner is not removed. It has the potential to increase. In Patent Document 10, the blade squeal is more effective than the cleaning performance.
As described above, many patent documents have been disclosed, but the fact is that there is no definitive method.

In the configuration of Patent Document 11, the longer the free length of the cleaning blade is, the easier it is to be distorted. Therefore, the adhesion with the photosensitive member becomes unstable, and cleaning failure is likely to occur. The gap in which the cleaning failure occurs depends on the surface state of the photoreceptor (for example, an increase in the coefficient of friction due to the attachment of the corona product) and also depends on the state of the edge of the cleaning blade. As long as it is judged from the drawings, tables and explanations based on the implementation, the free length (F / L) is 5 mm at the shortest, which is still too long to prevent poor cleaning, so that the distortion of the cleaning blade cannot be prevented. In addition, Patent Document 11 describes that the torque is set in a predetermined range in advance, but when no means for controlling the torque is taken, the torque increases due to the adhesion of the corona product. It is difficult to set a certain range. In particular, when the torque is increased, the degree of distortion of the blade edge is also increased, so that cleaning defects are more likely to occur. Therefore, it is determined that it is indispensable that the cleaning failure occurs early without waiting for the life of the photoreceptor.
The present invention includes a photoreceptor, to degrade the cleaning blade, also efficient photoreceptor attachment carrier which causes the abnormal image is to provide an and image forming equipment which can satisfactorily eliminated.
The present invention may be a large spherical toner having an average circularity is to provide Hisage image forming equipment which can perform stable cleaning.

To achieve the above object, according to the present invention, in an image forming apparatus, a cleaning blade for cleaning transfer residual powder on a rotatable image carrier, and an upstream side of the cleaning blade are disposed on the image carrier. It is characterized by having scraping means for reducing the amount of toner in the transfer residual powder and removing the carrier.

Scraping means may be obtained by arranging a large number of fins in the circumferential direction of the substrate with the base member at regular intervals.

  The fin of the scraping means is one of the first magnetic body and the structure in which the first magnetic body is attached to the tip of the fin of the film-like member. The first magnetic body and the image carrier are disposed close to each other in a non-contact state.

  In the case where the scraping means has the first magnetic body, it is preferable that a second magnetic body that is opposite to the first magnetic body to be opposite to the first magnetic body is disposed close to the scraping means. The second magnetic body is preferably disposed on the opposite side of the image carrier with the scraping means interposed therebetween. The magnetic flux density of the second magnetic body may be larger than the magnetic flux density of the first magnetic body. When the first magnetic body is a rubber magnet, the second magnetic body is a magnet other than the rubber magnet. Regardless of its form, the scraping means is provided so as to be rotatable in the counter direction with respect to the rotation direction of the image carrier.

According to the present invention, the inflow of the remaining residue powder cleaning blade as untransferred toner after image bearing member transfer (minimum required leaving) because it is able to reduce, become lighter of the cleaning blade load, It is possible to reduce deterioration due to wear of the cleaning blade and maintain durability. Further, since hard particles such as a carrier contained in the residual powder can be removed in advance by the scraping means, not only the image carrier but also the probability of damage to the cleaning device is reduced. Therefore, the image quality is maintained and the life of the image carrier and the cleaning device is not shortened. Furthermore, since the replacement frequency is reduced, the cost is reduced. Further, it is advantageous for energy saving and resource saving, and a favorable effect is obtained against environmental pollution.

According to the present invention, since a large number of fins are arranged at regular intervals in the circumferential direction of the substrate of the scraping means, the amount of toner flowing into the cleaning blade is not reduced more than necessary. It does not increase the frictional resistance between the blades . Therefore, the tip of the cleaning blade is not reversed, and the rotation of the image carrier is not locked. Further, since the gaps between the fins are open, there is no retention of toner and carrier. Accordingly, it and the scraping means falling into defective rotation, because it does not increase even the cleaning blade load, the durability of the cleaning blade is maintained.

According to the present invention, either the first magnetic body or the structure in which the first magnetic body is attached to the tip of the fin of the film-like member on the fin of the scraping means is attached to the image carrier. Since the carrier is adsorbed and removed without contacting the image carrier, there is no conveyance of the carrier to the cleaning blade , and neither the cleaning blade nor the image carrier is deteriorated by residual powder consisting of carrier and toner, and durability It becomes possible to maintain sex.

According to the present invention, since the first magnetic body of the scraping means and the image carrier are arranged close to each other in a non-contact state, carriers on the image carrier can be eliminated almost satisfactorily.
According to the present invention, since the second magnetic body that is opposite to the first magnetic body and the opposite magnetic pole is disposed close to the scraping means, the carrier attached to the first magnetic body of the scraping means is It is difficult to adhere to the side surface of the magnetic body and can be efficiently removed. Therefore, it is possible to remove the carrier semi-permanently from the photoreceptor without reducing the carrier removal efficiency by the scraping means.

According to the present invention, since the second magnetic body is disposed on the opposite side of the image carrier with the scraping means interposed therebetween, the carrier removed by the scraping means does not reattach to the image carrier. Thus, damage to the carrier cleaning blade and the image carrier can be prevented, so that durability can be maintained and image quality can be maintained well.

According to the present invention, since the magnetic flux density of the second magnetic body is made larger than the magnetic flux density of the first magnetic body, there is no residual carrier in the scraping means, and the cleaning blade and the image carrier are damaged by the carrier. The durability of the cleaning blade and the carrier is maintained, and deterioration of the image quality due to the durability can be suppressed.

According to the present invention, the first magnetic body constituting the scraping means is a rubber magnet, and the second magnetic body disposed close to the scraping means is a magnet other than the rubber magnet. There is no residue. When removing the carrier from the image bearing member, it is easy to process. To remove the carrier, the first magnetic body having a weak magnetic force is used. When the carrier is peeled off from the first magnetic body, the first magnetic body is removed. By disposing a second magnetic body having a magnetic force larger than that of the magnetic body, unlike the magnetic body, it is possible to prevent the carrier from reattaching to the image carrier. For this reason, there is no damage to the image carrier and the cleaning blade by the carrier, and the image carrier and the carrier can be maintained. As a result, environmental pollution such as energy saving and resource saving can be prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As a result of intensive studies in view of the problems of the present application, the inventors of the present application have confirmed that the problems can be solved by implementing the contents described below.

  1 and 2 are schematic views of an image forming apparatus using indirect electrophotography (zero graph method), respectively. The only difference between FIG. 1 and FIG. 2 is the type of the charge transfer device and the cleaning device 7, and the rest are all the same system configuration.

  The engine parts for image formation of the image forming apparatus are a photosensitive member 1 as an image carrier, a charging device 2, an image exposure device 3, a developing device 4, a transfer device 5, a separating device 6, a cleaning device 7, and a static eliminating device 8. It is configured. The image forming apparatus includes a scraping unit 72 in the vicinity of the outer peripheral surface of the photosensitive member 1 positioned between the charging device 2 and the transfer device 5, and a fixing device 9 on the downstream side of the sheet conveyance after the transfer device. . These components are disposed in the image forming apparatus main body 100. Below the image forming apparatus main body 100, a paper feed tray 10 that stocks paper 11 as a transfer medium is passed to the left side of the image forming apparatus main body 100. A paper discharge tray 12 for stocking 13 is provided.

  The photosensitive member 1 is a photoconductive layer in which a photosensitive layer is laminated on a conductive support by about 10 to 40 μm via an undercoat layer. A charging device 2 is placed in contact with or close to the photoconductor 1 and a DC voltage or a DC voltage on which an AC voltage is superimposed is applied to the photoconductor 1 to give a charge necessary for image formation.

  The charging device 2 includes a corona charging device, a contact charging device, and the like. The surface potential of the photoreceptor 1 is charged to about 400 to 800V. The photosensitive member 1 used in the present invention uses a function-separated type organic photosensitive member that operates with-(minus) polarity. Therefore, the voltage applied to the charging device 2 is negative. When the photosensitive member 1 is charged, a signal from the personal computer is input when a personal computer is connected to the apparatus directly or via a network. If the image forming apparatus main body 100 has a scanner function, the scanner function is used to read a document. A signal from a personal computer and an electrical signal of a CCD (charge coupled device) that reads a document are converted into a light dot pattern via a converter and applied to the photoreceptor 1. At this point, light attenuation occurs in the area irradiated with light, and an electrostatic latent image (electrostatic contrast) is formed between the area not irradiated with light. The potential after being attenuated by the irradiation light is about −50 V to −250 V, and a contrast potential of 250 V, preferably 350 V to 600 V is sufficient for image formation.

  This electrostatic latent image uses a two-component developer composed of toner and carrier, is developed by a magnetic brush type developing device 4 to which a developing bias is applied, and is transferred to a sheet 11 conveyed from a paper feed tray 10. 5 is transferred. The developing bias is a DC voltage (minus) or a DC voltage on which an AC voltage is superimposed. Thereafter, the paper 11 is peeled off from the photoreceptor 1 using the separating device 6, passes through the fixing device 9, becomes a hard copy 13, and is stocked on the paper discharge tray 12. Since a large amount of residual powder mainly composed of toner adheres to the photoconductor 1 after separation, it is cleaned using the cleaning device 7.

  In this embodiment, the cleaning device 7 houses the cleaning blade 71 and the scraping means 72 in its casing. The scraping means 72 may be disposed upstream of the cleaning blade 71 in the rotation direction of the photosensitive member 1, and is not necessarily provided in the cleaning device 7 together with the cleaning blade 71. That is, the cleaning blade 71 and the scraping means 72 may be configured independently from each other.

  The main function of the cleaning blade 71 is to clean the toner adhering to the surface of the photoconductor as is well known, but the scraping means 72 is buried in (included in) the transferred toner adhering to the photoconductor 1. The carrier is removed to such an extent that the photosensitive member 1 and the cleaning blade 71 are not damaged, and the burden on the cleaning blade 71 is reduced, and the frictional resistance between the cleaning blade 71 and the photosensitive member 1 is increased. However, it is provided for the purpose of suppressing the amount of toner flowing into the cleaning blade 71 to such an extent that the blade is not reversed or distorted. Its function is different from that of a known cleaning brush. I have to.

  After cleaning the toner, the photosensitive member 1 is irradiated with long-wavelength light on the entire surface of the photosensitive member 1 using the static eliminator 8 in order to erase the internal charge, thereby erasing the electrostatic latent image and preparing for the next copying cycle. .

  FIG. 3 shows an example of a process cartridge 150 in which three constituent units of the photosensitive member 1, the charging device (or charging member) 2, and the cleaning device 7 are combined. The developing device 4 can be incorporated in the process cartridge 150, and the cleaning device 7 can be configured as a single unit as a separate unit. That is, the process cartridge 150 integrally supports at least one component selected from the photoreceptor 1, the charging device 2, the developing device 4, and the cleaning device 7, and is attached to the image forming apparatus main body 100. The cartridge is detachable. By using a cartridge, if an abnormality related to these means occurs or if maintenance is required, a separate process cartridge (for replacement) should be prepared. There is a great merit that can be restored to the state, less trouble to the user, and is useful in the present invention.

  FIG. 4 is a schematic view of a so-called quadruple tandem full-color image forming apparatus as seen from the side, in which the developing device of the engine portion shown in FIG. 1 is composed of four systems of magenta, cyan, yellow, and black. The toner image formed on the body is transferred four times onto the conveyed paper and finally thermally fixed by the fixing device 8 to form one full-color image. In the configuration of FIG. 4, the scraping means 72 is disposed in the cleaning device 7 together with the cleaning blade 71. The process cartridge 150 shown in FIG. 3 can be mounted on the image forming apparatus shown in FIG.

Next, the configuration of the image forming apparatus will be described for each unit.
(Outline of photoconductor)
The photoreceptor 1 used in the present invention is a digital function-separated organic photoreceptor. FIG. 5 shows a cross-sectional configuration of the photoreceptor 1 (also referred to as “organic photoreceptor 1”). The function-separated organic photoreceptor 1 is a photoreceptor formed by laminating an undercoat layer 102, a charge generation layer 103, and a charge transport layer 104 in this order on a conductive support 101. Since this photoreceptor operates with negative charge, the charge transport layer 104 is a hole transfer type photosensitive layer. The durable number of the photosensitive member 1 shown in FIG. 5 is about 40,000 to 80,000 sheets in terms of A4 size paper.

  In recent years, demand for high-speed machines and full-color copiers has increased, but these image forming apparatuses are increasingly required to have high durability and high reliability. In order to be mounted on these image forming apparatuses, the photoreceptor 1 needs to have high wear resistance. There are various means for achieving high wear resistance, but at the same time, electrophotographic characteristics and image characteristics must be satisfied. FIG. 6 shows a cross-sectional configuration of the photoreceptor 1 in which a thin film having high wear resistance is formed on the charge transport layer in an amount of about 2 to 10 μm in order to achieve high durability. A charge transport layer 105 having high wear resistance is stacked on the layer 104.

Hereinafter, the photoreceptor used in the present invention will be described in detail for each layer.
(Conductive support)
As the conductive support 101 that can be used for the photosensitive member 1, there are many types such as a metal such as duralumin, aluminum, copper, brass, and stainless steel, a plastic material, a paper tube, and an insulator such as glass. Among them, in particular, a lightweight JIS standard 3003 type aluminum alloy which is excellent in mechanical strength, workability (cutting property), electrical characteristics and the like required as a conductive support is preferable. The aluminum support as the photoreceptor 1 is cut so that the characteristics such as roundness, straightness, and runout are within the specified values, and finally the surface finish (super Finishing and mirror finishing).

The conductive support 101 configured as the organic photoreceptor 1 is processed to have a thickness of 0.6 to 3 mm and an outer diameter of about 25 to 100 mm. The electrical resistance of the conductive support 101 is sufficient if the volume resistivity is 10 ⁶ Ω · cm or less, and if the volume resistivity is up to about 10 ⁹ Ω · cm, the electrophotographic characteristics are not substantially impaired. Can be used. As the electric resistance increases, the movement of holes in the photosensitive layer is hindered, so that the light attenuation characteristic becomes gradual and the electrophotographic characteristics deteriorate.

In aluminum, an insulating oxide film (Al ₂ O ₃ ) is formed immediately after cutting, but the oxide film formed in the atmosphere is thin, weak, and non-uniform, so that the charge injection blocking film (as a charge injection layer) It is insufficient as a blocking film. Therefore, it is a thin film (undercoat layer, intermediate described later) that has an anodizing treatment or that retains the time (up to several tens of msec) until the development is completed (charge during negative charge). Also referred to as a layer).
(Undercoat layer)
The purpose of forming the undercoat layer 102 is to prevent charge injection from the conductive support 101 side during charging, and incident light during image formation is reflected by the conductive support 101 and reenters the photosensitive layer. This is to prevent the image from being disturbed and to secure the charging potential, electrostatic contrast and uniform image (moire prevention, dot pattern reproduction, etc.) necessary for image formation. Therefore, it is indispensable for a digital image forming apparatus. The film thickness for preventing charge injection and preventing deterioration of electrophotographic characteristics is about 1 to 10 μm, and preferably 3 to 6 μm.

The subbing layer 102 is set to a volume resistivity on the order of 10 ¹⁰ to 10 ¹³ (Ω · cm), but as the film thickness increases, carriers formed by image formation (electrons when negatively charged) are subtracted. It takes time to move from the layer 102 to the conductive support 101 side. Therefore, the more frequently it is used, the more electrons accumulate at the interface of the charge generation layer, and the residual charge accumulates in the photosensitive layer, which tends to cause deterioration of the light attenuation characteristic, increase in charging characteristic potential, and positive charging. Change occurs, image density is lowered, afterimages are generated, and further, a problem such that the carrier during development is likely to adhere to the photoreceptor 1 is caused.

  On the other hand, as the film thickness is reduced, unevenness is easily formed in the coating film, and charge injection from the conductive support 101 (in this case, positive charges (holes)) is likely to occur. It will be sufficient and the image will be noisy. Therefore, it is not preferable to increase the film thickness, and 3 to 6 μm is preferable.

Examples of the resin used for the undercoat layer 102 include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane resins, melamine resins, and alkyds. Examples thereof include curable resins that form a three-dimensional network structure, such as melamine resins and epoxy resins. Further, fine powders such as metal oxides exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like, or metal sulfides and metal nitrides may be dispersed and contained. These undercoat layers 102 can be formed using an appropriate solvent and coating method. Furthermore, a metal oxide layer formed by using, for example, a sol-gel method using a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like is also useful as the undercoat layer 102 of the present invention.
(Charge generation layer)
The charge generation layer 103 is a layer that generates electron-hole pairs necessary for image formation by photons irradiated from the image exposure apparatus 3, and the sensitivity tends to increase as the amount of generated electron-hole pairs increases. In order to smoothly move electrons or holes generated by image exposure toward the surface or the charge of the conductive support 101, the charge transport layer 104 or the undercoat layer 102 in contact with the charge generation layer 103 It is desirable that the barrier at the interface be as low as possible, and any material can be used regardless of whether it is an inorganic material or an organic material, as long as the photosensitive material satisfies this condition.

  Examples of the charge generating material of the inorganic material include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compound, and amorphous silicon. Further, organic charge generating materials include metal phthalocyanine, phthalocyanine pigments such as metal-free phthalocyanine, azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triphenylamine skeleton, An azo pigment having a diphenylamine skeleton, an azo pigment having a dibenzothiophene skeleton, an azo pigment having a fluorenone skeleton, an azo pigment having an oxadiazol skeleton, an azo pigment having a bisstilbene skeleton, an azo pigment having a distyryl oxadiazol skeleton Azo pigments having a distyrylcarbazole skeleton, perylene pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and the like Azomethine pigments, indigoid pigments, bisbenzimidazo - there and Le pigments.

  The binder resin used as necessary for the charge generation layer 103 includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, polyarylate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N. -Vinylcarbazole, polyacrylamide, etc. are used. These binder resins can be used alone or as a mixture of two or more. Further, a low molecular charge transport material (electron transport material or hole transport material) may be added as necessary.

Examples of the electron transporting material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron accepting substances such as nitrodibenzothiophene-5,5-dioxide. These electron transport materials can be used alone or as a mixture of two or more.
Examples of the hole transport material include electron donating materials shown below. For example, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane, styrylanthracene, styryl Examples include pyrazoline, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, and thiophene derivatives. These hole transport materials can be used alone or as a mixture of two or more.

  The charge generation layer 103 is formed of a charge generation material, a solvent, and a binder resin as main components, and includes any additive such as a sensitizer, a dispersant, a surfactant, and silicone oil. May be included.

  As a method for forming the charge generation layer 103, a vacuum thin film manufacturing method and a casting method from a solution dispersion system can be mentioned. As the former method, a vacuum vapor deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, or the like is used, and the above-described inorganic materials and organic materials can be satisfactorily formed. Further, in order to provide the charge generation layer 103 by the casting method, if the inorganic or organic charge generation material described above is necessary, a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, or butanone is used together with a binder resin to form a ball mill, an atom, or the like. It can be formed by dispersing with a lighter, sand mill or the like, and applying the solution after diluting the dispersion appropriately. The application can be performed using a dip coating method, a spray coating method, a bead coating method, or the like.

The film thickness of the charge generation layer 103 provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm. Usually, it is applied to a thickness of 0.1 to 0.3 μm. When this film thickness is too thin, sensitivity failure occurs. However, when the film thickness is too thick, light attenuation deterioration and residual potential increase due to space charge occur, leading to image quality deterioration such as image density reduction and resolution reduction.
(Charge transport layer)
The charge transport layer 104 is formed to ensure a sufficient charging potential and a sufficient contrast potential necessary for image formation. The charge transport layer 104 generally has little polarity dependency, and polycarbonate resin (A type, C type, Z type, etc.) having a volume resistivity of about 10 ¹⁴ to 10 ¹⁸ (Ω · cm), styrene resin, An amorphous polyolefin resin or the like is used as a binder resin, and a donor, an antioxidant, a leveling material, or the like is further added. As the low molecular charge transport material constituting the charge transport layer 104, an oxazole derivative, an oxadiazole derivative, an imidazole derivative, a triphenylamine derivative, an α-phenyl stilbene derivative, a toniphenyl methane derivative, an anthracene derivative, or the like can be used. .

On the other hand, as the polymer charge transport material, the following known polymer charge transport materials can be used.
(1) Polymers having a carbazole ring in the main chain and / or side chain include, for example, poly-N-vinylcarbazole, JP 50-82056 A, JP 54-9632 A, and JP A Examples thereof include compounds described in JP-A Nos. 54-11737 and 4-183719.
(2) Examples of the polymer having a hydrazone structure in the main chain and / or side chain include compounds described in JP-A-57-78402 and JP-A-3-50555.
Examples of the (3) polysilylene polymer include compounds described in JP-A-63-285552, JP-A-5-19497, and JP-A-5-70595.
(4) Examples of the polymer having a tertiary amine structure in the main chain and / or side chain include N, N-bis (4-methylphenyl) -4-aminopolystyrene, JP-A-1-13061, As described in JP-A-1-19049, JP-A-1-1728, JP-A-1-105260, JP-A-2-167335, JP-A-5-66598, and JP-A-5-40350. There are compounds.
(5) Other polymers include, for example, formaldehyde condensation polymers of nitropyrene, compounds described in JP-A Nos. 51-73888 and 56-150749, and the like.

  The polymer having an electron donating group used in the present invention is not limited to the above polymer, but also a copolymer of known monomers, a block polymer, a graft polymer, a star polymer, and, for example, It is also possible to use a crosslinked polymer having an electron donating group as disclosed in JP-A-3-109406. Further, as the polymer charge transport material in the present invention, a polycarbonate having a triarylamine structure in the main chain and / or side chain is effectively used.

  On the other hand, examples of the polymer compound that can be used as the binder component include polystyrene, styrene / acrylonitrile copolymer, styrene / butadiene copolymer, styrene / maleic anhydride copolymer, polyester resin, polyvinyl chloride, and chloride. Vinyl / vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, polycarbonate resin (bisphenol A type, bisphenol C type, bisphenol Z type or copolymers thereof), cellulose acetate resin, ethyl cellulose resin, polyvinyl Thermoplastic or thermal such as butyral, polyvinyl formal, polyvinyl toluene, acrylic resin, silicone resin, fluorine resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin Including but of resin, but is not limited thereto. These polymer compounds can be used singly or as a mixture of two or more kinds, or copolymerized with a charge transport material.

  Examples of the dispersion solvent that can be used in preparing the charge transport layer coating solution include ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone, ethers such as dioxane, tetrahydrofuran, and ethyl cellosolve, toluene, xylene, and the like. Examples include aromatics, halogens such as chlorobenzene and dichloromethane, and esters such as ethyl acetate and butyl acetate, but it is desirable to avoid the use of halogen-based solvents in consideration of environmental destruction.

  In the present invention, an antioxidant is added to each layer such as a charge generation layer, a charge transport layer, an undercoat layer, a protective layer and an intermediate layer for the purpose of improving the environmental resistance and preventing the decrease in sensitivity and the increase in residual potential. Plasticizers, lubricants, UV absorbers, and low molecular charge transport materials can be added.

  The film thickness of the charge transport layer 104 is set in the range of about 10 to 40 μm, but is preferably set in the range of 10 to 30 μm, and is set to about 15 to 25 μm when high resolution is desired. When the film thickness is 10 μm or less, the electrostatic capacity becomes too large, and it becomes difficult to ensure the surface potential necessary for image formation. For image formation, it is desirable that the contrast potential is at least 250 V or more. However, if it is 10 μm or less, it becomes difficult to secure the contrast potential, the usable time becomes extremely short due to the abrasion of the photosensitive layer, and further, the contrast potential can be secured. It becomes difficult. On the other hand, when the film thickness is reduced, it is difficult to produce a photosensitive layer having a uniform film thickness, and image defects due to density unevenness and pinholes occur, resulting in an image quality with a poor SN ratio.

  When the thickness of the charge transport layer 104 is increased, the electrostatic capacity is reduced, so that a sufficient surface potential is secured, and an image quality with a good SN ratio can be obtained. However, as the thickness increases, structural defects relatively increase in the photosensitive layer, which hinders the movement of carriers (here, holes) and tends to cause undesirable phenomena such as afterimages.

  As the photosensitive member 1 used in the image forming apparatus, it is possible to endure the use of 40,000 to 80,000 sheets by forming up to the charge transport layer 104. However, in order to further increase the durability, suitable lubrication is possible. By applying the agent to the surface of the photoconductor and reducing the coefficient of friction of the photoconductor surface to around 0.2, it becomes possible to increase the durability to around 200,000 sheets, further increasing the practicality and environmental impact. It becomes effective for.

When the durability of the photoreceptor 1 is required to be 500,000 or more, there is a method described below.
(Charge transport layer)
There are several methods for increasing the durability of the photoreceptor 1, but a thin film having a high durability and a specific resistance of about 10 ¹² to 10 ¹⁴ Ω · cm and having a translucency of about 0.5 to 10 μm ( An organic film or an inorganic film) is generally formed on the photosensitive layer, and can be used effectively in the present invention if the electrophotographic characteristics and image characteristics are satisfied. However, even if the above-mentioned characteristics such as specific resistance and translucency are satisfied, the residual potential may increase or the sensitivity may decrease during repetition, and the photoconductor 1 is not always usable.

  In the present invention, a method of forming a photosensitive layer (referred to as a charge transport layer 105) having the property of a charge transport layer on the charge transport layer 104 is employed in order to have wear resistance and satisfy electrophotographic characteristics. ing. A schematic configuration of the photoreceptor 1 having the charge transport layer 105 is as shown in FIG. That is, by considering the charge transport layer 105 as an extension of the charge transport layer 104 and preventing the formation of a clear interface between both layers, the interface between both layers (charge transport layers 104 and 105) can be used even in repeated use. Therefore, it is possible to suppress the accumulation of residual potential, degradation of light attenuation characteristics, and reduction in charging potential caused by the height of the barrier.

  The charge transport layer 105 uses “a crosslinkable charge transport material having a reactive hydroxyl group”, “a thermosetting resin monomer”, and “a resin obtained by a crosslinking reaction with a thermosetting surfactant”. . Heating and crosslinking increase the hardness and form the photoreceptor 1 with excellent wear resistance.

  Examples of the crosslinkable charge transport material include bisphenol compounds described in JP-A-7-228557, diamine compounds described in JP-A-8-198825, JP-A-9-31035, JP-A-9-26369, Dihydroxyl group-containing diamine compounds described in JP-A-9-268164 and the like, JP-A-9-278723, JP-A-10-7630, hydroxyl-group-containing amine compounds, JP-A-9-194442 The hydroxyl group-containing stilbene compounds described above, the amine compounds described in JP-A-10-53569, and the like are all effective. These are raw materials for polymer charge transport materials, exhibiting excellent characteristics in charge transport ability and excellent in reactivity.

  Examples of thermosetting resin monomers include melamine resins, urea resins, epoxy resins, urethane resins, alkyd resins, acrylic resins, condensates such as organic silane condensates, or mixtures thereof, which are effective in the present invention. Can be used for For example, a melamine resin has a property of having a self-condensation property, can easily adjust the blending ratio with other raw materials, and has a high degree of design freedom. Epoxy resins also have a high degree of design freedom because there are many types of curing agents.

As a thermosetting surfactant, for example,
(1) As a copolymer containing a (meth) acrylate having a fluoroalkyl group described in JP-A-7-68398, fluorine described in JP-A-60-212410 and JP-A-60-228588 A block copolymer comprising a vinyl-type monomer containing no fluorine and a fluorine-containing vinyl-type monomer,
(2) As a fluorine-based graft polymer, for example, a comb-shaped graft polymer obtained by copolymerizing a methacrylate macromonomer having polymethyl methacrylate in the side chain and a (meth) acrylate having a fluoroalkyl group described in JP-A-60-187721 and so on.

  These fluorine-based resins are easily available as resin addition amounts. For example, fluorine-containing random copolymers are available from Asahi Kasei Co., Ltd. under the names of resin surface modifiers SC-101 and SC-105, As a fluorine-containing block copolymer, as a block copolymer composed of a fluorinated alkyl group-containing polymer segment and an acrylic polymer segment, Modiper F series F100, F110, F200, F210, F2020, etc. from Nippon Oil & Fats Co., Ltd. As the fluorine-based graft polymer under the trade name, they are commercially available from Toagosei Co., Ltd. under the trade names Aron GF-150, GF-300, and RESEDA GF-2000. These surfactants may be used alone or as a crosslinked resin component.

JP 2000-119354 A describes a material in which a silicone component is chemically bonded to a fluororesin. Hydrophobic resins ZX series ZX-007C, ZX-001, ZX-017 and the like are particularly resistant to contamination. It has excellent characteristics. When used as a cross-linked resin component, a copolymer of a methacrylic acid ester and a fluorinated alkyl acrylate is particularly effective.
In forming the charge transport layer 105, an antioxidant, a plasticizer, a low molecular compound such as an ultraviolet absorber, and a leveling agent can be added. These compounds can be used alone or as a mixture of two or more. The amount of the low molecular compound used is 0.1 to 50 parts by weight, preferably 0.1 to 20 parts by weight, based on 100 parts by weight of the resin component, and the amount of the leveling agent used is 100 parts by weight of the resin component. About 0.001 to 5 parts by weight is appropriate.

  Use of a fluorosurfactant contributes to increasing the hardness of the photoreceptor, and at the same time lowers the friction coefficient of the photoreceptor surface layer. Therefore, corona products such as ozone and nitrogen oxides that are generated when the photosensitive member 1 is charged in the image forming apparatus act, so that it is extremely effective in improving the friction coefficient and the cleaning failure that are increased. is there.

  When a crosslinkable resin is used, it is necessary to bond a charge transporting functional group to the crosslinkable resin to such an extent that photoinduced charge carriers can move in the protective layer, or to blend a polymer charge transport material. If it is possible to mix the low molecular charge transport material and the cross-linked resin, the low molecular charge transport material may be mixed, but it cannot be fixed in the protective layer, and the low molecular component is on the surface. May precipitate. By using the above-described polymer charge transport material for such a case, precipitation can be prevented and sensitivity characteristics can be improved.

  Methods for forming the photosensitive layer include dipping method, spray coating method, ring coating method, roll coater method, gravure coating method, nozzle coating method, screen printing method, etc. A suitable method is taken into consideration. In the case of forming the charge transport layer B105, the spray coating method and the ring coating method are particularly preferable because they are easy to ensure quality stability in production. The range of 15 to 35 μm is preferable.

  At the time of image formation, the photosensitive member 1 is charged to −400 to −800 V by the charging device 2 in the image forming apparatus. As the film thickness of the photosensitive layer increases, the capacitance decreases, so that a margin for the charging potential (a high charging potential can be obtained) occurs. However, when the charged potential decreases due to image exposure, the charge intensity decreases, so the movement of carriers in the photosensitive layer slows down, and holes or electrons accumulate in the photosensitive layer, and the photoreceptor functions sufficiently. Disappear. Therefore, it is not preferable to increase the film thickness more than necessary. If it is thin, a phenomenon opposite to that described above occurs and the accumulation of residual potential becomes low.

  The thickness of the charge transport layer 105 is preferably about 3 to 10 μm, and the total thickness of the charge transport layer including the charge transport layer 104 and the charge transport layer 105 is at most 50 μm. It is preferable to set the film thickness according to the charging potential used, and it is preferably 40 μm or less, more preferably 35 μm or less. The lower limit film thickness is set to 10 μm or more, preferably 15 μm or more.

The 10-point average roughness Rz _JIS (JIS B 0601) at the initial stage of the surface roughness of the photoreceptor 1 on which the charge transport layer 105 is formed is preferably 0.1 μm or more and 1.0 μm or less. This is to obtain a sharp image quality without being influenced by the roughness of the surface of the photosensitive member. When the cleaning blade 71 comes into contact with the photosensitive member 1, the blade edge is distorted so that the cleaning failure does not occur. It is a condition. Since the surface of the photoreceptor tends to increase in surface roughness due to repeated use, it is necessary to reduce the surface roughness at the initial stage. However, if the toner carrier can be completely prevented from coming off the blade, the surface roughness should be 3 μm or less. It is possible to suppress sufficiently. The term “blade removal of the toner carrier” as used herein refers to a so-called cleaning failure in which the toner and the carrier come out between the cleaning blade 71 and the outer peripheral surface of the photoreceptor 1. When the blade of the toner or carrier is removed, the surface roughness of the photosensitive member 1 depends on the situation, but when it is bad, the average surface roughness is about 5 μm, and the cleaning is locally poor. It becomes a factor to cause.

  As the surface roughness of the photoreceptor 1 becomes smaller, the adhesion of the cleaning blade 71 is improved, so that it is effective for toner cleaning. However, the organic photoreceptor tends to increase the frictional resistance by repeated use. Since the stick-slip phenomenon, local distortion of the blade, blade squealing and the like are likely to occur, it is not preferable that the surface roughness of the organic photoreceptor is too small. Further, as the surface roughness increases, the frictional resistance tends to be relaxed, but as described above, the image quality and cleaning properties are affected.

  In recent years, with the demand for higher image quality, polymerized toners with an average circularity of 0.96 or 0.98, which are almost spherical, and around 6 μm are used, but this toner has no sharpness and is nearly spherical. Even if there is a gap smaller than the toner diameter between the cleaning blade 71 and the outer peripheral surface of the photosensitive member 1, the cleaning blade 71 sinks while rotating, so that cleaning failure tends to occur. Therefore, when spherical toner is used, it is important that the cleaning blade 71 is in close contact with the photoreceptor 1 so that no gap is formed, and the surface roughness is such that the toner is allowed to sink. This situation is not desirable. For use over a long period of time, it is desirable that the initial surface roughness of the photoreceptor 1 be kept as smooth as possible.

  The spherical toner has a tendency to further reduce the particle diameter, and the tendency of the cleaning property to be influenced by the surface roughness of the photosensitive member 1 becomes stronger. Further, when the organic photoreceptor is used, the surface roughness gradually increases due to the rubbing of the cleaning blade 71, the carrier of the developer, paper dust (such as talc), and the like. Therefore, it is desirable to keep the initial value of the surface roughness of the photoreceptor 1 at a small level. For example, when 50,000 images are formed, the average roughness of the surface of the photosensitive member is about 1.2 to 2 (μm). However, if there is no defect on the edge of the cleaning blade 71, the cleaning performance is sufficiently maintained. Is done.

  When the surface of the photoconductor becomes rough, the cleaning blade 71 is also affected. Therefore, by suppressing the surface roughness of the photoconductor 1 to a low level, it is possible to maintain stable image quality over a long period of time. However, this is a case where the photoconductor 1 is not damaged by the carrier or the like adhering to the surface of the photoconductor.

  Even if the durability of the photoconductor is increased, if the carrier is pressed by the blade, the photoconductor 1 is surely scratched or dented. Further, since the highly durable photoconductor 1 is hard to be worn, the scratch is not repaired once it is damaged, that is, the photoconductor that is easily worn is worn, and the depth of the flaw is reduced, which affects the image quality. Has the harmful effect of continuing to occur. Therefore, it is important to avoid carrier adhesion to the photosensitive member 1 as much as possible. Even when the carrier is transported, avoid a state (gap) where the carrier is buried between the photosensitive member 1 and the cleaning blade 71. It is important to do.

  A higher hardness of the photoreceptor 1 is effective in that good image quality can be maintained over a long period of time. If no abnormalities such as scratches or dents appear in the image occur on the photosensitive member 1, a printing durability of 100,000 sheets or more can be guaranteed.

When the hardness of the photoreceptor 1 is expressed by, for example, pencil hardness, it is preferably 2H or more, preferably 3H or more. The reason for the determination based on the pencil hardness is effective in determining the resistance against scratching because the pencil edge is pressed against the photoreceptor and moved to determine the hardness based on the presence or absence of scratches. If it is 2H or more, the scratch resistance is improved and the image quality can be stabilized.
(Outline of the cleaning device)
A cleaning device 7 for cleaning residual powder such as toner and carrier remaining on the photoreceptor 1 is mainly composed of a cleaning blade 71. In FIGS. 1 and 2, the cleaning device 7 is integrated with a cleaning blade 71 and scraping means 72 for scraping and removing residual powder composed of toner, carrier, paper powder, and other powders. Built in the casing. This is because the unit can be made more compact if it is integrated, but it goes without saying that it may be configured as a single unit.

  The function of the scraping means 72 is slightly different from the purpose of a so-called cleaning brush, suppresses the carrier removal and the amount of toner flowing into the cleaning blade 71, reduces the burden on the cleaning blade 71, and increases durability. The purpose is to do.

  Suppressing the inflow of the toner amount suppresses the inflow of the toner to the cleaning blade 71 and reduces the burden on the edge as a contact portion between the cleaning blade 71 and the outer peripheral surface of the photosensitive member, and at the same time, the inflow of the toner mass. This is for preventing the inflow of carriers and reducing the inflow of carriers. When the amount of toner flowing into the cleaning blade 71 is extremely reduced, the burden associated with an increase in the frictional resistance between the cleaning blade 71 and the photosensitive member 1 is increased, and the wear of the edges of the photosensitive member 1 and the cleaning blade 71 is promoted. Is also connected. Therefore, it is desirable to reduce at least the amount of toner and allow it to flow into the cleaning blade 71.

  Regardless of the manufacturer, the adhesion of the carrier to the photoreceptor 1 is occurring to a greater or lesser extent, and it tends to be more and more likely to adhere as the carrier becomes smaller in size. The impact is also increasing. When the carrier is taken in between the ears of the cleaning brush, the photosensitive layer is worn by the carrier attached to the brush, or a part of the protruded carrier is reattached to the photosensitive member 1, and the photosensitive member 1 from the developing device 4. Even when adhesion does not occur, there is a risk that the photoconductor 1 may be scratched. Therefore, this situation needs to be completely prevented.

Hereinafter, the scraping means 72 and the cleaning blade 71 will be described in this order.
(Scraping means)
The scraping means 72 replaces the cleaning brush, and the main functions are the removal of the carrier and the suppression of the amount of toner flowing into the cleaning blade 71 as described above. As shown in FIGS. 7 to 11, the shape of the brush is completely different from that of the cleaning brush, and is greatly different in that it is not dense and rough. The cleaning brush has an auxiliary role of the cleaning blade 71. By rubbing the toner adhering to the photoreceptor 1 with the tip and back of the brush, the cleaning brush is forcibly separated from the photoreceptor 1 to remove the toner and perform cleaning. The aim is to improve the cleaning performance of the blade 71. Although the cleaning brush performs a sufficient function as a cleaning, since the brushes are dense, carriers can easily enter and accumulate between the brushes, which sometimes causes a problem of reducing the life of the photoreceptor 1. Many.

  The accumulated carrier causes the photoreceptor 1 to be worn or scratched. When the carrier accumulated in the cleaning brush is repelled in the direction of the blade and is sandwiched between the cleaning blade 71 and the photoconductor 1, the carrier is pressed against the photoconductor 1 and the photoconductor is damaged, and the photoconductor 1 is greatly scratched. Is formed and the cleaning blade 71 is distorted, the carrier comes off from the scratched part and causes cleaning failure. In addition, when the photosensitive member 1 is used for a long period of time, toner filming sometimes occurs from the vicinity of the scratch generation site. As described above, the cleaning brush in which the brush is formed on the entire surface of the roller has a property of accumulating the carrier, and thus may function as a harmful member for the photosensitive member 1.

  As described above, the scraping means 72 used in the present invention has a function different from that of the cleaning brush. That is, as described above, the influence of the carrier on the cleaning blade 71 is suppressed as much as possible, and the secondary influence is eliminated. In addition, the main purpose is to reduce the load of the cleaning blade 71 by reducing the amount of inflow of toner, to maintain the cleaning property and to extend the durability.

  For example, as shown in FIG. 7, the scraping means 72 has a plurality of fins 72b formed on a base 72a having a circular cross section at a right angle to a tangent to the outer peripheral surface of the base 72a, or a cross section shown in FIG. As shown by the figure, it has a shape provided with an inclination with respect to the outer peripheral surface of the base body 72a. A perspective view of the scraping means 72 shown in FIG. 7 is shown in FIG. 9, and a perspective view of the scraping means 72 shown in FIG. 8 is shown in FIG. These scraping means 72 have a rotatable roller shape whose both ends are rotatably supported.

  As shown in FIGS. 7 and 8, each scraping means 72 is composed of a large number of fins 72b fixed to the base 72a in the longitudinal direction at regular intervals, and is more sensitive than the cleaning blade 71 in position. It is desirable that it is disposed upstream of the body rotation direction and is rotated in the counter direction in order to enhance the scraping effect of the residual powder. The space between the fins 72b is to prevent the carrier from accumulating between the fins and to make it easy for the scraped toner and carrier to come out. The interval between the fins 72b is appropriately set between 1 to 3 mm (predetermined amount) depending on the material used. As shown in FIG. 1 and FIG. 2, a shielding plate 73e that covers between the cleaning blade 71 and the scraping means 72 may be installed as necessary. The fin 72b is basically composed of any one of a film, a brush, and a magnet.

The rotation of the scraping means 72 is a counter direction rotation with respect to the photosensitive member 1, and the number of rotations is set between 50 and 250 rpm. Usually, if there is a rotational speed of about 150 to 220 rpm, the purpose of reducing residual powder, particularly toner, and eliminating the carrier as much as possible is achieved. These are arranged in either a contact state or a non-contact state depending on the material, shape, hardness, and the like. The length of the fin 72b in the longitudinal direction (axial direction of the scraping member) needs to be at least long enough to cover the development area.
(Scraping means using film)
A film having a thickness of 25 to 150 μm is used for the fin 72b. The amount of biting into the photoreceptor 1 is +1 mm to -0.2 mm. The width of the fin 72b in the direction of the photoreceptor, that is, the amount of protrusion from the outer peripheral surface of the base 72a needs to be changed depending on the system, but is usually set between 2 and 10 mm. If the thickness of the film is small, there is no problem in image formation even if it contacts the photoreceptor 1, and there is no problem in image formation. However, as the film becomes thicker, the photoreceptor 1 is damaged. Become. Therefore, it is necessary to change the amount of biting into the photoreceptor 1.

  Since the fin 72b is bent when the width (projection amount) is increased, the depth of damage at which the photoreceptor 1 is damaged even if contacted is reduced. It is preferable to set in the (+) direction to bite into the photoconductor 1 as the fin film thickness decreases, and in the (−) direction away from the photoconductor 1 as the thickness increases. Usually, it is desirable that a slightly thicker film (for example, around 100 μm) is set so as not to come into contact with the photoreceptor 1. Here, the degree of non-contact means that the distance between the photoreceptor 1 and the tip of the fin 72b is set to about 0.1 to 0.2 (mm).

  When using a thin film of 25 to 40 (μm), the biting depth is set to +1 mm, and when using a medium to thick film of 60 to 150 (μm), set to −0.1 to −0.2 mm. . This is because when the film of 25 to 40 (μm) is set to +1 mm or more, the resistance due to the toner on the photoreceptor increases, and the possibility that the film deforms increases. Further, as the amount of biting decreases, the film bends and escapes, so that the deterring power of the toner and the carrier is reduced, and the function as the scraping means 72 is not effective. The film thickness needs to be 25 μm or more, preferably 50 μm, from the viewpoint of strength and scraping effect (deterrence). At this time, the film width (protrusion amount) in the direction approaching the photosensitive member 1 is desirably set within a range of 2 mm to 10 mm.

  As the film becomes thicker, the mechanical strength increases and bending becomes less, so that the toner deterrence increases and the carrier scraping effect tends to increase. When the thickness is about 100 μm, it varies depending on the width of the fin, but it is easy to be rubbed against the photoconductor. When a 100 μm film is used, the distance between the photoreceptor and the fin is preferably set between 0.05 mm and 0.3 mm. This gap is generally enough to allow about one sheet of paper in circulation. The thickness of a suitable film as the scraping means 72 is about 50 to 120 μm, and the biting depth is −0.1 mm to −0.2 mm.

  The fins 72b scrape the residual powder in a right angle (FIG. 7) or counter direction on a base 71a composed of a metal rod rod of φ5 to 10 mm, resin, and resin coating. Inclined (Fig. 8) and fixed. The inclination angle is desirably in the range of 50 ° to 80 °.

Film materials that can be used for fins include resin products such as polyethylene terephthalate (PET) resin, polycarbonate resin, and polyimide resin. Moreover, although it is not classified with a film, resin, such as a bakelite, can also be used.
(Scraping means using a brush)
FIG. 10 shows scraping means 721 using a brush. The scraping means 721 can be the same as the nylon fiber, polyester fiber, polyethylene fiber, carbon fiber, etc. used for the cleaning brush. The fiber diameter is 5 to 20 (D / F), the brush density is 10,000 to 100,000 (lines / inch ² ), and the length of the brush ear is set according to the amount of biting into the photoreceptor 1. D represents denier and F represents a filament.

  In the case of a cleaning brush, if a brush material with a suitable material and fiber diameter (equivalent or approximate to the cleaning brush) is selected, a shallow rubbing scratch will occur on the surface of the photoreceptor, but it will be a deep scratch. hard. Therefore, the amount of biting into the photoreceptor 1 is desirably set to +1 mm or less, preferably about 0 to +0.5 mm. If the amount of biting is too large, the resistance of the brush to the photosensitive member 1 increases, causing mechanical troubles (for example, the photosensitive member 1 is overloaded and hinders rotation, and the photosensitive member 1 is scraped unevenly by frictional heat. If it is too short, the toner and the carrier may come off and the effect of the arrangement may not be exhibited.

  When the brush material is fixed to the scraping means 721 by flocking or an adhesive, a brush in which the brush materials adjacent to each other and having a width of 1 mm to 2 mm are planted on the base cloth (base) is attached as shown in the perspective view of FIG. The interval between the brushes (the pitch between adjacent brushes) is suitably 1 mm to 2 mm.

The brush used as the scraping means 721 is solidified with a resin or the like while leaving the tip portion in a brush shape, leaving 1 to 3 mm from the tip. That is, the protrusion amount from the outer peripheral surface of the base 72a is set to 1 to 3 mm. This is because when the residual powder on the photoreceptor 1 is scraped off, the amount of toner that comes off increases and the carrier stays between the brushes as much as possible. If it is 1 mm or less, the photoconductor 1 is easily scratched, and if it is 3 mm or more, the toner carrier stays and the carrier is detached, and the possibility of reaching the cleaning blade 71 increases. Usually, about 1 to 2 mm is sufficient. If the length of the brush (fiber) cannot be increased in space, and the length of the brush is 3 mm or less (for example, 2 mm or 1.5 mm) even after being implanted, the brush is particularly solidified. It is not necessary to do this, and only the brush may be fixed to the base body 72a. When using a brush as a scraping means, it is necessary to prevent the brush ears from falling apart.
(Scraping means using magnetic material)
The scraping means using a magnet as the magnetic body will be described mainly with reference to FIGS. 11 has a cross-sectional shape shown in FIG. 7, and a rubber magnet serving as a first magnetic body having a width of 0.4 mm to 1 mm and a height of 1 to 3 mm is used at the tip of a thin film-like fin 72b. The scraping means 722 which fixed magnet A72c is shown. A rubber magnet is a sheet-like magnet that contains a magnetic powder such as a ferrite magnet in rubber and can be easily processed with scissors or a knife. The magnetic force is the smallest among the various magnets. FIG. 12 shows scraping means 723 in which the entire fin is composed of a magnet A72c (rubber magnet).

  In FIG. 11 and FIG. 12, a magnet B 72d as a second magnetic body having a stronger magnetic force (residual magnetic flux density) than the magnet A 72c is spaced apart from the photoreceptor 1 across the magnet A 72c. Fixedly arranged. In this embodiment, these magnets 72d are fixed to the casing of the cleaning device 7 as shown in FIGS.

  The magnetic force (residual magnetic flux density) of a commercially available rubber magnet (isotropic) is about 40 to 74 (mT) (= 400 to 740 (gauss)). Considering the distance from the photoconductor 1, the charged potential after transfer of the photoconductor 1, the size of the carrier, the amount of toner, etc., a suitable magnetic force for each magnet is set. If a manufacturer (for example, TDK Co., Ltd.) is requested, it is possible to obtain a rubber magnet having a higher magnetic force.

  When the scraping means 722 and 723 are provided in this way, the carrier in the toner adhering to the surface of the photoreceptor 1 is attracted by the magnetic force from the magnet A 72 c of the scraping means 722 and 723. In order to attract (remove) the carrier adsorbed by these magnets A72c, the magnet B72d disposed on the opposite side (opposite side) needs to be a magnet having a magnetic force higher than these.

  Generally, there is a limit to the magnetization of a rubber magnet, and it cannot be magnetized more than necessary. Therefore, a ferrite magnet, a neodymium magnet, a samarium cobalt magnet, or the like is used as the magnet B72d, but a relatively inexpensive ferrite magnet is usually sufficient. The size may be about 2 to 5 mm in thickness and about 3 to 10 mm in width. The total length may be any length that satisfies the image forming area length in the axial direction of the photoreceptor 1. The larger the magnitude of the magnetic force, the better. However, actually, a magnetic force in the range of 250 to 400 (mT) (= 2500 to 4000 (gauss)) may be used.

  As shown in FIG. 13, the distance L2 between the magnet A72c and the magnet B72d may be a distance that does not cause a malfunction when the magnetic force and carrier of the magnet are attracted to the magnet B72d and deposited, and the two magnets are 2 to 10 mm. It is preferable to fix at a distance L2 between. When the magnet A 72 c is installed, the magnet A 72 c is fixed so that the lines of magnetic force are strongest with respect to the fin direction, that is, the direction in which the fin extends and the proximity to the photoreceptor 1.

  The distance L1 between the surface of the photoreceptor 1 and the magnet A72c may be a minimum distance that does not damage the surface of the photoreceptor, and may be set at a distance L1 between 0.1 and 0.5 mm. As a result, the carrier can be efficiently sucked while scraping off the toner from the surface of the photoreceptor 1.

FIG. 14 shows a state where a scraping means 722 having a magnet A72c made of a rubber magnet attached to the tip of the fin 72B is installed in the cleaning device 7 and the toner 40a and the carrier 40b are scraped off by the scraping means 722. It is a schematic diagram which shows. Residual powder after transfer (toner + carrier + paper powder, etc.) adhering to the photoreceptor 1 is reduced by passing between the scraping means 722 and the surface of the photoreceptor 1, and more than the scraping means. It flows into the cleaning blade 71 arranged on the downstream side in the photoconductor rotation direction. On the other hand, the carrier 40b contained in the toner is attracted by the magnet A72c and separated from the photoreceptor 1, and is attracted by the magnet B72d disposed on the opposite side of the photoreceptor 1 with the scraping means 722 interposed therebetween. Reattachment to the body 1 is prevented.
(Cleaning blade)
The detailed configuration of the cleaning blade 71 will be described with reference to FIGS. In this embodiment, the cleaning blade 71 includes a holder 71a, a blade 71b, a reinforcing seal 71c as a reinforcing member, and a mounting bracket 71f. However, all of these components do not necessarily have to be aligned. The function of the cleaning blade 71 is to completely dam up and remove the toner 40a shown in FIG. 14 so that the next image forming process (charging) is not affected. Even if it reaches the position 71, it is completely blocked, and it is prevented from entering under the cleaning blade 71, that is, between the surface of the photoreceptor.

  A basic configuration of the cleaning blade 71 is shown in FIG. The blade 71b has a bilaterally symmetric shape, and its base end is mounted inside a U-shaped holder 71a. On both surfaces of the free end of the blade 71b protruding from the holder 71a, reinforcing seals 71c having the same left and right dimensions are attached over the entire length in the longitudinal direction. The free end refers to a portion (protruded portion) that is not fixed to the holder 71a from the tip of the holder 71a to the tip of the blade 71b, and is the free length of this portion. This free length is set to 3 to 8 (mm) in the present invention.

  The holder 71a can be made of materials such as aluminum, stainless steel, and iron. The wall thickness is about 1 to 2 mm, and it is attached to the image forming apparatus and abuts. When the photosensitive member is rotated, no deformation occurs, and if it is easy to process and low cost, other materials than the above can be used. Is possible. The reason why the holder 71a is bilaterally symmetric and the reinforcing seal 71c has the same left and right dimensions is that the cleaning blade 71 can be reversed and used.

  The cleaning blade 71 constantly rubs against the photosensitive member 1, and if the cleaning failure sometimes occurs, the tip edge wears, and the higher the contact pressure, the easier the wear, and the life of the blade decreases. Although the cleaning blade 71 is normally used in only one direction, it is desirable to use it for a long time from the viewpoint of resource saving, and the reverse use of the cleaning blade 71 embodies this, and uses twice as long. It means you can do it.

  The reinforcing seal 71c is a film member having a film thickness of 25 to 300 μm. As the film member, polycarbonate resin, polyethylene terephthalate resin, vinyl chloride resin, or the like is preferably used. If it is 25 μm or less, the strength is insufficient, and if it is 300 μm or more, the strength is sufficient, and a thickness greater than that is not required. Usually, it is sufficient if it is in the range of 100 μm to 200 μm. For these films, strong double-sided adhesive tapes from 3M (Scotch brand ST-416P, 4595MP, etc.) and hot melt adhesives are used well, but in order to maintain long-term stability, hot melt adhesives Is preferable.

  FIG. 16 is a perspective view of the cleaning blade of FIG. Reference numeral 71e denotes a mounting positioning hole, which is positioned and supported by being inserted into a projection (not shown) formed in the mounting bracket 71f shown in FIG. Reference numeral 71d indicates a screw for mounting and fixing the cleaning blade 71 on the mounting bracket 71f.

  FIG. 17 shows an example of a shape in which the blade 71b sandwiched between the holders 71a is attached to the attachment fitting 71f. The cleaning blade 71 having the holder 71a and the blade 71b can be easily removed from the mounting bracket 71f with the screw 71d. Therefore, when the replacement time comes, the cleaning blade 71 is reversed and attached again with the screw 71d. Can be used continuously without replacing the cleaning blade. It is up to the user to use the reverse or not.

  FIG. 18 shows an example of a state in which the cleaning blade 71 is in contact with the photosensitive member 1, and the edge portion is shaped to come into surface contact with the photosensitive member 1. The cleaning blade 71 shown in FIG. 15 is fixed to the mounting bracket 71 f and is mounted so as to come into counter contact with the rotation direction of the photosensitive member 1. The contact angle is suitably about 15 to 30 (°). As the contact angle increases, the nip width increases and the probability that the toner and the carrier are sandwiched increases. Therefore, it is preferable that the contact angle is small, the edge crushing is reduced as much as possible, the line contact is made, and the contact with the photoreceptor 1 is maintained, thereby maintaining a good cleaning property. Leads to.

  FIG. 19 is a view showing the state of the edge portion of the cleaning blade 71 in a state where the photosensitive member 1 is rotated in the direction of the arrow. The edge portion of the cleaning blade 71 is dragged in the rotation direction of the photosensitive member 1, and is crushed and distorted. By this crushing, the shallow rubbing scratches on the photosensitive member are almost fully blocked, and toner is prevented from coming off.

  The cleaning blade 71 is subjected to a cleaning operation by applying a contact pressure in the range of 15 to 30 (g / cm) to the photoreceptor 1. The contact pressure is an important characteristic for cleaning the residual powder. If the contact pressure is too small (15 g / cm or less), the contact pressure becomes insufficient, and a gap is easily formed between the photoreceptor 1 and a cleaning defect is caused. In some cases (30 g / cm or more), scratches are formed on the photosensitive member 1 to increase wear, causing breakage or distortion on the blade edge, and wear is also promoted. That is, the deterioration of both the photoreceptor 1 and the cleaning blade 71 is promoted.

  In other words, the range of the contact pressure at which cleaning is satisfactorily performed is 15 to 30 (g / cm), preferably 20 to 25 (g / cm). Note that even if the contact pressure is 15 g / cm or less, there is no problem from the beginning, and the friction coefficient of the surface layer of the photoreceptor gradually increases when used to some extent (for example, 100 sheets or 1000 sheets). Then, the cleaning blade 71 is distorted or vibrated, resulting in poor cleaning. The reason why the trouble occurs depends on how the image forming apparatus is used and the degree of adhesion of the carrier. Therefore, a cleaning failure occurs, or the photosensitive member 1 is scratched or a blade is damaged. The number of durable sheets until a defect occurs varies.

  In a spherical toner (polymerized toner) having a high circularity of about 0.96 or about 0.98, if the contact pressure is low, cleaning failure is likely to occur. Therefore, when using a polymer toner having a high degree of circularity, it is preferable to set the contact pressure higher (30 g / cm to 50 g / cm) than when a pulverized toner is used. This prevents a gap from being formed between the edge of the photosensitive member 1 and the cleaning blade 71, so that the toner rejection rate is improved and the cleaning property is improved. There is a limit.

  That is, the cleaning performance is greatly influenced by the surface condition of the cleaning blade 71 and the photosensitive member 1 (the size of the friction coefficient, the depth of the scratch, the number, etc.), and therefore cannot be determined only by the contact pressure. Many. By increasing the contact pressure, wear of the photoreceptor 1 and the cleaning blade 71 is promoted. Further, it is pointed out that by increasing the contact pressure, both the photoreceptor 1 and the cleaning blade 71 are scratched or missing due to rubbing, and it is easy to cause cleaning failure.

When the reinforcing seal 71c is used together with the cleaning blade 71, the contact surface with the photosensitive member 1 is strengthened and the adhesion is improved as in the case where the hardness of the blade 71b is increased without increasing the contact pressure. Even with spherical toner, it becomes possible to perform good cleaning.
For the blade 71b, polyurethane (or urethane) rubber which shows uniform adhesion to the photoreceptor 1 and has little mechanical and chemical deterioration is preferably used. The blade 71b is obtained by cutting a plate-like rubber having a JIS-A hardness of 58 ° to 80 ° and a thickness of 1.5 to 3 mm into a width and a length to be used. When the JIS-A hardness is low, the adhesion to the photoreceptor 1 is improved, but the line contact of the blade edge for good cleaning becomes difficult, and the frictional resistance with the photoreceptor 1 increases. In addition, since the curl due to the contact pressure becomes severe, the toner and the carrier are likely to be pressed against each other, and malfunctions are likely to occur. Therefore, the limit of the hardness of the blade 71b is 58 °. On the other hand, when the hardness is increased, the line contact with the photosensitive member 1 is satisfactorily performed, and if the blade and the photosensitive member are not damaged, good cleaning is guaranteed. However, if a scratch is formed, a gap is generated, and cleaning failure is likely to occur. In other words, the cleaning blade 71 having a hardness of about 90 ° can be used in the initial stage. However, in the long term, the cleaning blade 71 has a lack of flexibility due to scratches on the photosensitive member and blade edge and increased hardness due to the corona product. Sex is unstable.

  By sticking the reinforcing seal 71c, the shortage of hardness is compensated and the line contact is sufficiently performed. Therefore, the blade 71b can be used even if the JIS-A hardness is low. A JIS-A hardness of about 80 ° is sufficient. Usually, if it exists between 60 degrees-80 degrees, it can fully be used.

  When used in the image forming apparatus, a contact pressure (pressing) is applied to the cleaning blade 71, so that the clearance from the photosensitive member 1 is approximately 0 μm. Even if the surface roughness of the blade edge is about 30 μm, there is no problem with the cleaning property, but if it is kept small, the margin will be increased, and it is possible to extend the life until defective cleaning occurs. Become.

  By setting the thickness of the blade 71b to 1.5 to 3 (mm), the effect of the reinforcing seal 71c is enhanced, and the line contact of the blade edge is better maintained. As a result, the toner can be cleaned satisfactorily and is effective in suppressing the penetration of the carrier and spherical toner. If the thickness is less than 1.5 mm, there are problems in cleaning properties and durability. If the thickness is 3 mm or more, the blade edge is crushed and the toner and the carrier are likely to sink under the blade. Usually, it is good in balance to use a blade having a thickness of about 2 mm.

The cleaning blade 71 is manufactured by, for example, applying an adhesive on both sides in a holder 71a (a metal such as iron or aluminum processed into a U-shape) that opens to about 1 to 2 mm on both sides. A blade 71b made of polyurethane rubber having a width of 1.5 to 3 mm cut into a strip shape is inserted, and crimped so as to close the mouth of the holder. As the adhesive, a commercially available one-component or two-component adhesive, double-sided tape, or the like can be used. The length needs to be long enough to cover the development area. Thereafter, it is screwed to the mounting bracket 71f.
(Coefficient of friction or surface free energy of photoconductor)
The coefficient of friction or surface free energy of the photoconductor shows a relatively low value of about 0.25 to 0.4 when measured by the Euler belt method in an initial state without any scratches, but is used in an image forming apparatus. By doing so, the photoreceptor is damaged and the gloss is lost, or the oil added as a leveling agent is removed, so that the friction coefficient gradually increases and becomes a high value of 0.6 or more. The coefficient of friction is an important item in image formation, and problems arise if it is too high or too low. If the friction coefficient is high, problems such as poor cleaning properties and poor transfer occur, and the photosensitive member is easily worn.

  On the other hand, if it is too low, the toner cannot be properly developed, resulting in a decrease in sharpness, a decrease in cleaning property due to slipping under the toner blade, and a problem such as image flow due to lack of removal of the adhering substance on the photoreceptor. .

  The numerical limit of the coefficient of friction depends on the system conditions for image formation, and therefore cannot be determined unconditionally. However, the coefficient of friction of a good photoreceptor is 0.2 to 0.4 when measured by the Euler belt method. It is desirable to set between (preferably 0.35). As a result, it is possible to obtain good effects in any of the cleaning properties of the residual powder (blocking at the blade edge of the toner), the image quality, and the durability improvement of the photoreceptor.

  As described above, the new friction coefficient of the photoreceptor 1 is about 0.25 to 0.4. Even if this number is in the process of image formation, it is unlikely to cause a problem. This is because the friction resistance between the photosensitive member and the cleaning blade is reduced due to the adhesion of the lubricant and toner to the cleaning blade. However, when the cleaning blade and / or the photoconductor is replaced during maintenance, the edge of the cleaning blade 71 is temporarily coated with a lubricant such as polyvinylidene fluoride, but it is insufficient. The frictional resistance between the cleaning blades 71 is extremely large, and even if the photosensitive member is rotationally driven, it may not be able to rotate sufficiently. In this case, the gear may be damaged or the photoreceptor 1 may be damaged. In order to avoid this abnormality, the coefficient of friction on the surface of the photoreceptor should be lowered.

  In order to make the initial rotation of the photosensitive member 1 smooth, the friction coefficient may be made sufficiently low. Even if the friction coefficient is initially reduced to 0.2 or less (˜0.1), the friction coefficient increases with the rotation of the photosensitive member 1 and the surface roughness of the cleaning blade 71 is as small as 10 μm or less. In a photoconductor that can obtain a normal image, even if there is a scratch, the blade edge sufficiently closes the scratch and hardly causes poor cleaning.

  As a means for reducing the surface friction coefficient of the photoconductor 1, there is a method of applying a lubricant to the surface of the photoconductor. For example, polytetrafluoroethylene (PTFE) is an excellent lubricant, and powdered PTFE (for example, Lubron L-2.L-5 manufactured by Daikin Industries, Ltd.) is applied to a cotton cloth or non-woven fabric to scratch the photoreceptor. The friction coefficient can be easily reduced by applying the material while rubbing to the extent that no friction is applied to form a thin layer of lubricant as a whole (it is not necessary to apply uniformly). Examples of fluorine resin powders other than PTFE include PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin) and the aforementioned polyvinylidene fluoride. However, the effect as a lubricant is low, and the photoconductor is simply rotated. However, depending on the method of application, blade rubbing noise may occur when the photosensitive member rotates, and smooth rotation may occur.

  Thus, by forming a thin film of PTFE on the photoconductor, the friction coefficient can be lowered to about 0.2. Since the coefficient of friction after application is maintained for a long time unless it is used, this treatment may be performed immediately after the production of the photosensitive member or immediately before packaging on the wrapping paper.

  If the friction coefficient is a numerical value of about 0.25 or less, the rotation becomes easy. Therefore, even the highly durable photoconductor 1 can be rotated without being damaged. Even if the coefficient of friction decreases to 0.2 or less in the initial stage, if an image is formed, the lubricant is removed by a cleaning blade, a developer, etc., and the coefficient of friction increases, and the image quality is not affected at all.

  If the photosensitive member 1 can be easily rotated, the toner will serve as a lubricant to some extent, and can be rotated smoothly. However, if there is no lubricant or alternative means for smoothing the surface, the coefficient of friction gradually increases to 0.5 to 0.6, which causes problems in terms of cleaning properties, image quality, and durability of the photoreceptor. .

  That is, a means for applying a lubricant to the surface of the photoreceptor is required. As a means for reducing the friction coefficient, the wax fine particles and the fluororesin particles having the effect of lowering the friction coefficient of the photosensitive member 1 are dispersed in the toner, or a lubricant application device is provided downstream of the cleaning device for photosensitivity. There is a method of supplying to the surface of the body. As other means, there is also a means for adding about 30 to 60% by weight of fluororesin particles to the surface of the photoreceptor. However, this means is not suitable for the present invention in terms of durability and image quality of the photoconductor because the surface roughness of the photoconductor surface is increased and the surface is easily worn by adding fluororesin particles. .

  As the toner, low melting point toner is becoming the mainstream for power saving and avoiding environmental pollution. From the standpoint of improving the image quality, not only the cleaning property but also the transfer property and the releasing property at the time of fixing must be good. As an improvement measure, there is a means for containing a wax near the surface of the toner.

  The wax is contained in an amount of about 5 to 10% by weight with respect to the toner. By selectively containing the wax near the surface of the toner, a part of the wax acts on the photoreceptor 1 and the friction coefficient of the photoreceptor 1 can be lowered. In this case, the reduction of the friction coefficient proceeds slowly. In the initial stage, the effect of the lubricant pre-applied to the photoconductor is effective, and in the long term, the friction coefficient is reduced to a level of about 0.3 due to the effect of reducing the surface free energy of the photoconductor and the effect of wax in the toner. It can be changed. However, the amount of toner used may vary depending on the image area of the document, or the friction coefficient may be violated due to the formation of filming. Therefore, since the friction coefficient may increase depending on the copying conditions and the like, it is desirable to maintain the friction coefficient by the above-described means.

The coefficient of friction in the present invention is measured by the following measuring means.
Measurement of coefficient of friction of photoconductor A photoconductor for measurement was fixed to a pedestal, and a fine paper of 85 μm in thickness (made by Ricoh, type 6200 paper, using vertical eyes) cut to a width of 30 mm and a length of 290 mm was used as a belt. Place the high-quality paper on the photoconductor, attach a weight of 100gr to one end of the belt, attach a digital force gauge for weight measurement to the other end, slowly pull the digital force gauge, and Is read, and the (static) friction coefficient μs is calculated from Equation 1.

μs = 2 / π × ln (F / W) (Formula 1)
However, μs: Static friction coefficient, F: Reading load, W: Weight of weight, π: Circumferential ratio Further, the average circularity described in the present invention is 5 μm or more when the number of measured particles is 1000 particles or more. A particle having a particle size is selected, and a toner image is projected to calculate the perimeter.

Average circularity = Σ (perimeter of circle with the same projected area as particle image / perimeter of particle projection image) /
Number of particles to be measured (Formula 2)
As a measuring device, FPIA-1000 type manufactured by Sysmex Corporation can be used.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited only to these Examples.
Preparation Example 1 of Photosensitive Member for Evaluation (Photosensitive member A)
Apply an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution to the following composition on a φ30 mm x 340 mm aluminum drum (JIS standard 3003 series), and heat-dry. Thus, an undercoat layer of 3.5 μm, a charge generation layer of 0.3 μm, and a charge transport layer of 23 μm (or 28 μm) were formed. The heat drying conditions were 120 ° C. for 20 minutes for the undercoat layer, and 130 ° C. for 20 minutes for the charge generation layer and the charge transport layer. These types of photoreceptors are referred to as photoreceptor A. The film thickness of the photosensitive layer is an average value of 13 measurement values measured using an eddy current film thickness meter (Fischer type mms).
(Coating liquid for undercoat layer)
Alkyd resin (Beccosol 1307-60-EL, manufactured by Dainippon Ink and Chemicals)
10 parts by weight melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
7 parts by weight Titanium oxide (CR-EL manufactured by Ishihara Sangyo Co., Ltd.) 40 parts by weight Methyl ethyl ketone 200 parts by weight [Coating liquid for charge generation layer]
5 parts by weight of bisazo pigment having the following structure (manufactured by Ricoh)

Polyvinyl butyral (XYHL, manufactured by UCC) 1 part by weight Cyclohexanone 200 parts by weight Methyl ethyl ketone 80 parts by weight (Coating liquid for charge transport layer A)
Polycarbonate resin (Z polycarbonate, viscosity average molecular weight; 50,000, manufactured by Teijin Chemicals Ltd.)
10 parts by weight 7 parts by weight of low molecular charge transport material having the following structure

Tetrahydrofuran 100 parts by weight 1% silicone oil (KF50-100CS manufactured by Shin-Etsu Chemical Co., Ltd.) Tetrahydrofuran solution 1 part by weight Photoconductor for evaluation 2 (photoconductor B)
The surface layer of the photoreceptor A having a photosensitive layer thickness of 23 μm is further spray-coated using the coating liquid for the charge transport layer B shown below, and heat drying at 170 ° C. for 30 minutes to achieve a target charge of 5 μm. A transport layer B was laminated to produce a 28 μm photoconductor for evaluation.
This type of photoreceptor is referred to as photoreceptor B.
[Coating solution for fluorine resin-containing charge transport layer B]
3 parts by weight of low molecular charge transport material with the following structure

Fluorine-based surfactant (thermosetting surfactant Modiper F200, manufactured by NOF Corporation)
5.7 parts by weight (solid content: 2.1 parts by weight)
Melamine resin (thermosetting resin monomer Super Becamine L-145-60, manufactured by Dainippon Ink & Chemicals, Inc.) 8.2 parts by weight (solid content: 4.9 parts by weight)
Tetrahydrofuran 180 parts by weight cyclohexanone 53 parts by weight The spray coating conditions for the charge transport layer are as follows.
(Coating conditions for charge transport layer B)
Coating liquid discharge rate: 11 ml / min
Coating liquid discharge pressure: 2.4 kgf / cm ²
Rotating speed of coated drum: 120rpm
Coating speed: 28mm / sec
Distance between spray head and coated drum: 5cm
Number of times of coating: Twice Example 3 of photoconductor for evaluation (photoconductor C)
After dip coating with an undercoat layer (UL) coating solution having the following specifications, a JIS standard 3003 series aluminum alloy drum machined to φ100 mm, length 360 mm, and wall thickness 1.2 mm was used as a conductive support. C. for 20 minutes to form an undercoat layer of about 3.5 .mu.m. Next, after dip-coating with a coating solution for a charge generation layer (CGL) using a titanyl phthalocyanine-based charge generation material, it was dried by heating at 120 ° C. for 20 minutes to form a 0.2 μm charge generation layer. Furthermore, after immersing in the coating solution for charge transport layer A (CTL) using the charge transport material described in the formula (4) to coat the charge transport layer A, heat drying at 130 ° C. for 20 minutes is performed. Then, an organic photoreceptor having an average film thickness of the photosensitive layer of about 25 μm (or 30 μm) was produced. These types of photosensitive members are referred to as a photosensitive member C.
(Coating liquid for undercoat layer)
Alkyd resin (Beckosol 1307-60-EL, manufactured by Dainippon Ink and Chemicals) 6 parts by weight Melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals) 4 parts by weight Titanium oxide (CR-EL Ishihara Sangyo Co., Ltd.) 40 parts by weight methyl ethyl ketone 200 parts by weight (charge generation layer coating solution)
Oxotitanium phthalocyanine pigment (Ricoh) 2 parts by weight Polyvinyl butyral (Union Carbide: XYHL) 0.2 part by weight Tetrahydrofuran (Kanto Chemical Co.) 50 parts by weight (coating liquid for charge transport layer A)
Bisphenol Z-type polycarbonate (manufactured by Teijin Chemicals Ltd .: Z Polica Mv50,000)
10 parts by weight 8 parts by weight of low molecular charge transport material having the following structure

Tetrahydrafuran 200 parts by weight 1% silicone oil (KF50-100CS manufactured by Shin-Etsu Chemical) Tetrahydrafuran solution
Preparation Example 4 of Photosensitive Member for 1 Part by Weight Evaluation (Photosensitive member D)
Further, spray coating is performed on the photosensitive layer C having a photosensitive layer thickness of 25 μm using the following coating solution for the charge transport layer B, followed by heating and drying at 170 ° C. for 30 minutes, and the charge transport layer B having a thickness of 5 μm. And a photosensitive member for evaluation having a photosensitive layer thickness of 30 μm was produced. This type of photoreceptor is referred to as photoreceptor D.
(Coating liquid for charge transport layer B)
3 parts by weight of low molecular charge transport material of the following structural formula

Fluorine-based surfactant (thermosetting surfactant hydrophobic resin ZX-007C, manufactured by Fuji Kasei Kogyo Co., Ltd.) 10 parts by weight (solid content: 3.5 parts by weight)
Melamine resin (thermosetting resin monomer Super Becamine L-145-60, manufactured by Dainippon Ink & Chemicals, Inc.) 5.8 parts by weight (solid content 3.5% by weight)
Tetrahydrofuran 190 parts by weight Cyclohexanone 53 parts by weight (coating conditions for charge transport layer B)
Coating liquid discharge rate: 10 ml / min
Coating liquid discharge pressure: 2.4 kgf / cm ²
Rotating speed of coated drum: 120rpm
Coating speed: 28mm / sec
Distance between spray head and coated drum: 5cm
Number of coating times: 3 times (example of scraping means preparation)
[Example 1 of preparation of scraping means (scraping means (A))]
Insert a 1mm-thick vinyl chloride cylinder into which a slit of 1mm in depth, 1mm in width and 326mm in length and 8 slits formed at intervals of about 3.1mm is inserted into a stainless steel core with a diameter of 6mm. A rubber magnet (approx. 64 mT) (= magnet A) cut to a thickness of 0.6 mm, a width of 3.3 mm, and a length of 326 mm is inserted into the base material that has been injected and fixed to the substrate, and fixed with an adhesive from Cemedine. Then, the scraping means as shown in FIG. 12 was completed. This is called scraping means (A).

The protruding width of the rubber magnet is 2.3 mm, which is approximately 0.4 mm from the photosensitive member in calculation. The size of 3 × 5 × 325 (mm) bonded to a 1 mm aluminum plate is placed on the upper part of a toner recovery coil (not shown) of the cleaning device section of the prepared evaluation machine (IMAGIO 7070 modified machine, manufactured by Ricoh). A ferrite magnet (327 mT) (= magnet B) was fixed. The distance between the scraping means (A) and the magnet B is about 3 mm.
[Production Example 2 of scraping means (scraping means (B))]
A stainless steel core with a diameter of 6 mm is inserted into a 1 mm-thick vinyl chloride cylinder in which slits having a depth of 1 mm, a width of about 0.5 mm, and a length of 326 mm are formed at regular intervals of about 4.1 mm, and cyanoacrylate A polyethylene terephthalate film (PET) having a thickness of 90 μm, a width of 2.3 mm, and a length of 326 mm is inserted into a base made by bonding and fixing with a resin, and fixed with an adhesive (for example, Super X) of Cemedine. A scraping means such as 9 was prepared. This scraping means is called scraping means (B).

  When this scraping means is attached to an evaluation machine equipped with a φ30 mm photoconductor (Ipsio Color 8100 modified machine, manufactured by Ricoh Co., Ltd.), the calculation results in the fin projecting about 1.3 mm from the vinyl chloride cylinder, and between the photoconductor and the fin. The gap is about 0.3 mm.

In the scraping means (B), a 160 μm PET film (the protruding width from the aluminum plate is 4 mm) fixed to a 1 mm aluminum plate with an adhesive is fixed as a flicker bar over a length of 326 mm. The amount of biting between the fins and the flicker bar is about 0.2 mm in calculation and is slightly oscillated.
(Production example of cleaning blade)
[Preparation Example 1 of Cleaning Blade (Cleaning Blade (A))]
Two 326 x 6 x 1 (mm) iron plates (holders) with three 3.5 mm holes for screwing and two positioning holes, holes for screwing at the same position as the iron plate A polyurethane rubber (blade) having a JIS-A hardness of 68 ° cut into 326 × 12.5 × 1.96 (mm) was prepared. The two blades were bonded with a hot melt adhesive with the blade sandwiched between them so that the upper end portions of the polyurethane rubber coincided (the free length at this time was 7 mm). Further, a polycarbonate resin film (reinforcing seal) of 326 mm × 5 mm × 200 μm was bonded and fixed 1 mm above the edge of the blade with an adhesive of Cemedine. This is designated as a cleaning blade (A-1).

  In the same manner, the blades replaced with 58 °, 77 °, 80 °, and 89 ° were prepared as cleaning blade (A-2), cleaning blade (A-3), and cleaning blade (A-4), respectively. The cleaning blade (A-5) is used.

  Next, a set screw hole at the position of 6 mm from the upper surface is L-shaped at the upper end with two holes for positioning at the center and two at both ends and two positioning holes inside the holes at both ends, 326 × The cleaning blade (A-1) to cleaning blade (A-5) were screwed to a 15 × 1 (mm) mounting bracket to produce a blade cleaning device.

These cleaning blades were attached to an evaluation machine (Ipsio Color 8100 modified machine manufactured by Ricoh Co., Ltd.) for evaluation. In addition to the above, a cleaning blade without a reinforcing seal was prepared for comparison. The contact pressure of the cleaning member is about 21 to 23 (g / cm).
[Production Example 2 of Cleaning Blade (Cleaning Blade (B))]
The cleaning (B) is prepared in the same manner as the cleaning blade (A), and is prepared for an evaluation machine (Imagio MF7070 remodeling machine, manufactured by Ricoh) different from the above-mentioned evaluation machine. Provided. The polyurethane rubber blade used at this time had a JIS-A hardness of only 68 °. The contact pressure of the cleaning blade at the time of mounting was about 23 g / cm.
(Examples 1-2)
As an evaluation machine, a Corona-charged IMAGIO MF7070 machine (manufactured by Ricoh) equipped with an organic photoreceptor having a diameter of 100 mm was used.

  Photosensitive bodies A and B as evaluation photoconductors, scraping means (A) as scraping means, and cleaning blade (B) as cleaning blades were prepared and set in an evaluation machine. The scraping means is set to such a size that it can be attached as it is when the straight hair type cleaning brush is removed. The number of revolutions of the scraping means was performed under the conditions set in the evaluation machine.

  The entire surface of the photoconductor is rubbed with a non-woven fabric (Asahi Kasei Heisegase) containing PTFE powder (Daikin Industries L-2) in advance, and the coefficient of friction is between 0.2 and 0.3. Pretreatment was performed to enter.

  A black toner (containing 8% by weight of rice wax (melting point 83 °)) having an average circularity of 0.97 and an average particle diameter of 5.7 μm prepared by a suspension polymerization method manufactured by Ricoh Co. A magnetic material having a particle diameter of 53 μm (manufactured by Ricoh) was used, and the toner concentration was 6% by weight based on the carrier.

  Using spherical toner with wax added to the toner realizes energy saving and environmental pollution (CO2 emission suppression, power consumption reduction, elimination of harmful gases, etc.), low temperature fixing, oilless fixing, transferability, high resolution This is to achieve a low friction coefficient (low free surface energy) and the like of the photoreceptor.

  In the image evaluation, an original A-3 version manuscript (test chart) on which a chart for evaluation of resolving power (JIS Z 6008 1982, manufactured by Kodak Company) was attached was used.

  As the image forming conditions, the charging potential of the photosensitive member was set to -850V, the image portion potential was set to -180V, and the developing bias voltage was set to -600V. The image forming conditions were set such that the charging potential was set slightly higher than the normal use conditions, the potential difference between the charging potential and the developing bias was widened, and the carrier was likely to adhere to the photoconductor.

Evaluation was made by passing 50,000 sheets of A-4 size paper (using a character chart with an image area of 6% for the manuscript), and images (background stain, streaks, gradation reproducibility, etc.) taken before and after the test chart. ), The effect was judged by the film thickness of the photosensitive layer, the appearance of the photoreceptor and the blade edge, and the like. For observation of the size of the blade edge defect, an ultra-deep shape measuring microscope (VK-8500 manufactured by Keyence Corporation) was used.
The results are shown in Table 1.

(In the table) The amount of abrasion of the photosensitive layer indicates the amount of abrasion at 50,000 sheets, and the judgments of “○” and “◎” mean that there is no practical problem. The difference between ◯ and ◎ is simply the difference between the amount of wear and the amount of wear within the range of the examples. Even in Example 1, an ability of 15 μm or more is recognized in terms of durability.

The combined use of the scraping means using magnets and the cleaning blade with the reinforcing seal attached makes almost no carrier at the cleaning blade position, and the photoconductor is scratched by suppressing the inflow to the cleaning blade by the scraping means. There was almost no rubbing scratch due to the rubbing of the blade, and the residual toner on the photoconductor after cleaning was almost at the level of nothing, and it was at a level where there was no practical problem at all. Further, the toner scraping effect by the scraping means was almost sufficient, and the amount of toner deposited on the cleaning blade was good. In addition, the coefficient of friction of the photoconductor measured by removing it was as good as 0.32 on the average of the measured values at five locations. As a result, the background stain on the copy is at a level that causes no problem with visual observation, the gradation of the low density level (0.06 to 0.5) is reproduced without unevenness, and abrasion of the photosensitive layer is 0.28 μm on the photosensitive member C. In the photoreceptor D in which the charge transport layer B was further formed on the charge transport layer A, the wear of the photosensitive layer was greatly reduced, and a good result of 0.11 μm was obtained.
(Comparative Examples 1-4)
As an evaluation machine, an Imagio MF7070 remodeling machine (manufactured by Ricoh Co., Ltd.) mounting the same organic photoreceptor of φ100 mm in Examples 1 and 2 was used. As the photoconductor for evaluation, the photoconductor C, the photoconductor D, and the scraping means were not used, and a cleaning blade (B) was prepared as a cleaning blade. However, two types of cleaning blades were prepared, one with a reinforcing seal and one without. B * in Table 2 means a type B cleaning blade without a reinforcing seal. The position of the scraping means was the same as the standard cleaning brush.
The organophotoreceptor was previously surface treated with PTFE powder to reduce the friction coefficient.

The toner is a black toner having an average circularity of 0.97 and an average particle size of 5.7 μm (containing 8% by weight of rice wax (melting point: 83 °)), which is also produced by the suspension polymerization method manufactured by Ricoh. A magnetic material (made by Ricoh Co., Ltd.) having a diameter of about 53 μm was used, and the toner concentration was 6% by weight based on the carrier. The image forming conditions, image evaluation, etc. are all the same as in Examples 1-2.
The results are shown in Table 2.

(In the table) × means that there is a problem in practice.
When the cleaning brush is used without using the scraping means, a slight amount of carrier is confirmed on the edge of the cleaning blade and the cleaning brush, and a large number of carriers are also confirmed in the cleaning brush. Scratch was confirmed locally. The amount of toner scraped off was insufficient, and the amount of toner accumulated on the cleaning blade was larger than that in Examples.

  There is a difference in toner cleaning properties between when the reinforcing seal is applied and when it is not applied. When the reinforcing seal is not applied, the residual powder is clearly confirmed after cleaning and is clearly visible on the paper. Dirt was confirmed. The density level is about 0.06 to 0.07 (the level that cannot be confirmed visually or with a magnifying glass is about 0.05). Further, unevenness was observed in the gradation pattern on the low density side.

  Since the carrier was not sufficiently removed, a part of the carrier was sandwiched between the blade and the photoconductor, and a scratch occurred on the photoconductor and a defect of about 40 μm occurred on the blade edge. However, such a defect itself is at a level with a slight margin for causing a cleaning defect, but the friction coefficient is 0.35 to 0.4 (not shown in Table 2) in the vicinity of the site where the scratch occurs. ) And a little high.

As a result, about four black stripes close to a belt shape were observed on the image. This is presumed to be because a factor (for example, toner filming) in which a blade edge is distorted and a cleaning failure occurs (for example, toner filming) due to a locally high friction coefficient. In addition, image unevenness that appears to be the influence of the carrier occurred.
The judgment is x.
(Examples 3 to 6)
As an evaluation machine, a modified Ipsio Color 8100 machine (manufactured by Ricoh Co., Ltd.) using a non-contact charging member mounted with a photoconductor of φ30 mm was used. Photoreceptors A and B as evaluation photoreceptors, scraping means (B) as scraping means, and cleaning blade (A-1) and cleaning blade (A-3) as cleaning blades are prepared and evaluated. Set in the machine.

  The organophotoreceptor was pretreated with a non-woven fabric (Asahi Kasei Heisegase) containing PTFE powder (Daikin Kogyo L-2) in advance, and mounted on an evaluation machine.

  Since the Ipsiocolor 8100 is a quadruple tandem full color printer using four photoconductors, only the magenta station and the cyan station were used in the evaluation. Examples 3 and 5 are magenta stations, and examples 4 and 5 are cyan stations. In addition, dummy drums were set in the yellow station and black station other than the above and excluded from the evaluation targets.

  As the toner, magenta toner (containing 6% by weight of rice wax (melting point: 83 degrees)) having an average circularity of 0.968 and an average particle diameter of 6.2 μm prepared by a suspension polymerization method manufactured by Ricoh Co., Ltd., average circularity Is a cyan toner (rice wax (melting point 83 ° C.) containing 6% by weight) having an average particle diameter of 6.4 μm, and a magnetic material having an average particle diameter of 62 μm (made by Ricoh) is used for the carrier. The toner concentration was 5.5% by weight with respect to the carrier.

In order to confirm the effect on the image, the test chart of the external personal computer was input to the evaluator, and the hard copy obtained by image formation was evaluated.
As the image forming conditions, the charging potential of the photosensitive member was set to -800V, the image portion potential was set to -120V, and the developing bias was set to -500V. Also in this case, the image forming condition was set a little higher to set the carrier to be easily attached.
Evaluation was made by passing 50,000 sheets of A-4 size paper (using a character chart with an image area of 6% input from a PC as a manuscript) and using test charts taken before and after that (ground stain, 1-dot reproducibility) The effect was judged by the film thickness of the photosensitive layer, the appearance inspection of the photoreceptor and the blade edge, and the like.
The results are shown in Table 3.

  The removal of the carrier by the scraping means is inferior to the case of using a magnet, and there were cases (Examples 3 and 5) that reached (attached) the cleaning blade, but the toner in the cleaning device and fin inspection Many carriers are observed, and it is judged that the carrier is removed by the scraping means (the carrier mixed in the toner is appropriately discharged, but the carrier attached to the cleaning blade or sandwiched between the blades is difficult to remove) . This is advantageous for reducing the damage caused by the carrier. In other words, the carrier is dispersed, and the probability that the toner gets under the cleaning blade is reduced. If the number of carriers is large, the ratio of being disturbed by the toner is reduced, so that the possibility of increasing damage increases.

  Even if the carrier adheres to the cleaning blade, the carrier does not reach the pressure contact with the cleaning blade due to the effect of the reinforcing seal of the toner cleaning blade, and the photosensitive member and the cleaning blade suffer little damage. As a result, there were no black streaks or black bands in the image.

Since the charging member is non-contact, it is effective against toner contamination, but it is still insufficient to avoid contamination, and since the gap with the photoconductor is 50 μm or less, it is slightly but slightly whitish. It was done. With this level of contamination, the electrical resistance of the charging member is still sufficiently maintained, and the image is not affected. Further, the surface of the photoreceptor was sufficiently glossy, the 1-dot image was reproduced well, and the character image was also sharp. All the judgments were ◎ or ○.
(Comparative Examples 5 to 8)
As an evaluation machine, a modified Ipsio Color 8100 machine (manufactured by Ricoh Co., Ltd.) using a non-contact charging member equipped with a photoconductor of φ30 mm, which is the same as in Examples 3-6. As the evaluation photoconductor, the photoconductor A and the photoconductor B, the scraping means are not attached, the cleaning brush is left as it is, and the cleaning blade (A-1) and the cleaning blade (A- 3) was prepared and set in an evaluation machine.

  However, cleaning blades with and without a reinforcing seal were prepared and set on an evaluation machine. A-1 * and A-3 * in Table 3 mean cleaning blades without a reinforcing seal. The cleaning blade (A-1) has a JIS-A hardness of 68 °, and the cleaning blade (A-3) has a 77 °.

  The organophotoreceptor was pretreated with a non-woven fabric (Asahi Kasei Heisegase) containing PTFE powder (Daikin Kogyo L-2) in advance, and mounted on an evaluation machine. The evaluation positions were the same as in Examples 3 to 6, and only the magenta station and cyan station were used. Comparative Example 5 and Comparative Example 7 were magenta stations, and Comparative Example 6 and Comparative Example 8 were cyan stations.

As the toner, magenta toner (containing 6% by weight of rice wax (melting point: 83 degrees)) having an average circularity of 0.968 and an average particle diameter of 6.2 μm prepared by a suspension polymerization method manufactured by Ricoh Co., Ltd., average circularity Was 0.972 and an average particle size of 6.4 μm cyan toner (containing 6% by weight of rice wax (melting point 83 °)), and a magnetic material having an average particle size of 62 μm (manufactured by Ricoh) was used as the carrier. The toner concentration was 5.5% by weight with respect to the carrier.
Image forming conditions and evaluation conditions are the same as those in Examples 3 to 6.
The results are shown in Table 4.

When a normal cleaning brush is used without a scraping means, the carrier damming ability is insufficient, and in any case, more carrier adhesion to the cleaning blade is observed than the normal imaging conditions. It was confirmed that a part was sandwiched between the photoreceptor and the cleaning blade. In addition, in the charging member, numerous streaks due to toner contamination were observed in the rotation direction. For this reason, shading unevenness occurred in a one-dot image.

  When the reinforcing seal is not attached to the cleaning blade (Comparative Examples 5 and 7), biting of the carrier into the photosensitive member is observed, and several thin (about 0.2 to 0.5 mm) black streaks are formed on the image. Several black belts were observed. Due to the bite of the carrier, the blade edge was greatly damaged. This deficiency is a major cause of the black belt. When the defect is 70 μm, a cleaning defect is likely to occur even if the coefficient of friction of the photosensitive member is as low as 0.25.

On the other hand, when the reinforcing seal was affixed to the cleaning blade, the carrier bite into the photoconductor was observed, but it was not deep, and no black band or black streak appeared on the image. However, since it was observed with a magnifier of 10 times, it was observed that it was slightly thinly soiled, so the cleaning performance was not perfect, and if the image was continuously created, the soiling could become worse. Have The 1-dot reproducibility was almost good. Judgment in terms of durability and image quality of the photoreceptor was x in any condition.
(Examples 7 to 10)
The evaluation machine used was an Ipsio Color 8100 modified machine (manufactured by Ricoh). Photoreceptors A and B as evaluation photoreceptors, scraping means (B) as scraping means, cleaning blade (A-2), cleaning blade (A-4) and cleaning blade (A as cleaning blades) -5) was prepared and set in an evaluation machine. The cleaning blade (A-2) has a JIS-A hardness of 58 °, the cleaning blade (A-4) is 80 °, and the cleaning blade (A-5) is 89 °.

All the organic photoreceptors were subjected to a surface treatment with PTFE powder (L-2 manufactured by Daikin Industries) and mounted on an evaluation machine. As the mounting positions of the photoconductors, Example 7 and Example 9 were magenta stations, and Example 8 and Example 10 were cyan stations. Dummy drums were set at the other yellow and black stations. The toner, image forming conditions, and evaluation conditions are the same as those in Examples 3-6 and Comparative Examples 5-8.
The results are shown in Table 5.

In the table, Δ indicates a practical limit, and ○ and ◎ indicate that there is no practical problem.
When a reinforcing seal was applied to the cleaning blade, the cleaning performance was good or almost good, but when polyurethane rubber having a hardness of 90 ° was used for the cleaning blade, the line contact with the photosensitive member was not Good, but less flexible. Therefore, when the photoconductor has scratches such as scratches or foreign matters, the gap cannot be sufficiently prevented, and a slight amount of toner is confirmed on the photoconductor, but it can be visually confirmed on the image after transfer. There was no degree of soiling. However, in the loupe, a streak-like thing was confirmed. After 50,000 sheets, it was judged that the background dirt was still within the practical range, but there is a possibility that the abnormalities will expand with further use. The determination is Δ.

  When a member with a rubber hardness of 58 ° is used, a reinforcing seal is attached, but when the cleaning blade is pressed against the photoconductor, the bending of the edge portion becomes large. It is easy to get caught between them, and it is easy to bite in.

  For this reason, the carrier bites into the photoconductor, dents and scratches were observed on the photoconductor, and a thin strip pattern was confirmed on the image. Although the 1-dot reproducibility was slightly uneven, it was an unevenness that could not be understood without careful attention. However, 58 ° is a little insufficient in terms of preventing the carrier from entering. The determination is Δ close to ○.

  On the other hand, in Photoreceptor B in which the abrasion resistance of the photoconductor was improved, the scratch was relatively good, better than that in Example 7, and good with almost no dot reproducibility and unevenness. When the rubber hardness of the blade was 80 °, the cleaning property and the carrier biting prevention property were improved in a balanced manner, and the background stain, the photoreceptor appearance characteristics, and the image quality were good.

1 is a schematic view showing an embodiment of an image forming apparatus for explaining a copying process of the present invention. It is an example of a schematic diagram of an image forming apparatus of another system explaining a copying process of the present invention. FIG. 2 is a schematic diagram illustrating a process cartridge in which a cleaning device including a photosensitive member, a charging device, a cleaning blade, and a scraping unit is integrated. FIG. 2 is a schematic diagram illustrating a tandem full-color image forming apparatus including four systems of a copying process, a transfer device, and a fixing device. FIG. 2 is a schematic diagram for explaining a layer structure of a photoreceptor having a two-layer photosensitive layer used in the present invention. FIG. 2 is a schematic diagram illustrating a layer structure of a photoreceptor having a three-layer photosensitive layer used in the present invention. It is the schematic which looked at the scraping means with which the fin was attached to the base | substrate from the side surface. It is the schematic which looked at the scraping means with which the fin was attached to the base | substrate with the inclination from the side surface. It is a perspective view which shows schematic structure of the scraping means to which the fin shown in FIG. 7 was attached. It is a perspective view which shows schematic structure of the scraping means in the case of using the brush shown in FIG. 8 as a fin. It is the schematic which looked at the structure of the scraping means which used the 1st magnetic body for the front-end | tip part of a fin, and the relative positional relationship with a 2nd magnetic body from the side surface. It is the schematic which looked at the relative positional relationship with the structure of the scraping means by which the whole fin was comprised with the 1st magnetic body, and the 2nd magnetic body from the side surface. It is the schematic which shows a positional relationship with a scraping means, an image carrier, and a scraping means and a 2nd magnetic body. It is a schematic diagram which shows the state which removes the carrier and toner by the scraping means using a magnetic body. It is the schematic which looked at the structure of the cleaning blade which can be used reversed and used for this invention from the side. FIG. 16 is a perspective view of the cleaning blade shown in FIG. 15. It is a side view of the cleaning blade in a state of being attached to the mounting bracket. FIG. 18 is a schematic view showing a state in which a cleaning blade is fixed to a mounting bracket different from FIG. 17 and is brought into counter contact with the image carrier. FIG. 6 is a schematic diagram for explaining a state of an edge of a cleaning blade when an image carrier is rotated.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image carrier 2 Charging device 3 Image exposure device 4 Developing device 5 Transfer device 7 Cleaning device 40a Toner 40b Carrier 71 Cleaning member (cleaning blade)
71a holder 71b blade 71c reinforcing member 72, 721, 722, 723 scraping means 72a base 72b fin 72c first magnetic body (magnet A)
72d Second magnetic body (magnet B)
DESCRIPTION OF SYMBOLS 100 Image forming apparatus body 101 Conductive support body 102 Undercoat layer 103 Charge generation layer 104 Charge transport layer 105 Charge transport layer 150 Process cartridge

Claims (6)

In the image forming apparatus,
A cleaning blade for cleaning the transfer residual powder on the rotatable image carrier;
Provided on the upstream side of the cleaning blade , comprising scraping means for reducing the amount of toner in the transfer residual powder on the image carrier and removing the carrier,
The scraping means is a substrate and a plurality of fins arranged at regular intervals in the circumferential direction of the substrate,
The image forming apparatus according to claim 1, wherein the fin has one of a first magnetic body and a structure in which the first magnetic body is attached to a tip of a fin of the film-like member.   The image forming apparatus according to claim 1, wherein the first magnetic body of the scraping unit and the image carrier are disposed in close proximity to each other in a non-contact state.   3. The image forming apparatus according to claim 1, wherein a second magnetic body that is opposite to the first magnetic body is disposed adjacent to the scraping unit. 4.   4. The image forming apparatus according to claim 3, wherein the second magnetic body is disposed on the opposite side of the image carrier with the scraping means interposed therebetween.   5. The image forming apparatus according to claim 3, wherein the magnetic flux density of the second magnetic body is larger than the magnetic flux density of the first magnetic body.   6. The image forming apparatus according to claim 3, wherein the first magnetic body is a rubber magnet, and the second magnetic body is a magnet other than the rubber magnet.

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