JP2002229301A - Electrophotographic device and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic device and a process cartridge which suppress increase of electrophotographic photoreceptor driving torque and hardly generate breakage of a cleaning member. SOLUTION: In the electrophotographic device provided with means of electrification, exposure, development and transfer by a contact electrifying system and a cleaning means, the electrophotographic device and the process cartridge are distinguished by that cycle time of the electrophotographic photoreceptor is below 0.44 sec/cycle, a polymer having a siloxane unit expressed by general formula (1) (wherein R1 and R2 are each alkyl group, aryl group or aralkyl group; and n is integer of >=3) described below is contained as a binding resin of a surface layer of the electrophotographic photoreceptor having a photosensitive layer on a conductive supporting body and further electrification width in the electrifying means and transfer width in the transfer means satisfy following formula: (electrification width-transfer width)<=6.0 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic apparatus and a process cartridge, and more particularly to an electrophotographic apparatus and a process cartridge having a high process speed and a short cycle time. More specifically, the present invention relates to an electrophotographic apparatus and a process cartridge in which a surface layer of an electrophotographic photosensitive member suitable for this and a charging / transfer member having a specific length are combined.

[0002]

2. Description of the Related Art An electrophotographic method is disclosed in U.S. Pat.
As shown in the specification of JP-A-91, a photoconductive material is used in which the electric resistance changes according to the amount of irradiation received during image exposure, and in a dark place, the support is coated with an insulating substance. The basic characteristics required of an electrophotographic photoreceptor using this photoconductive material include (1) being able to be charged to an appropriate potential in a dark place, (2) being small in potential dissipation in a dark place, (3) Quickly dissipating the charge by light irradiation, and the like.

Conventionally, as an electrophotographic photoreceptor, an inorganic electrophotographic photoreceptor having a photosensitive layer containing an inorganic photoconductive compound such as selenium, zinc oxide and cadmium sulfide as a main component has been widely used. However, these are the above (1) to
The condition of (3) is satisfied, but thermal stability, moisture resistance, durability,
Productivity was not always satisfactory.

[0004] In order to overcome the drawbacks of the inorganic electrophotographic photosensitive member, electrophotographic photosensitive members containing various organic photoconductive compounds as main components have been actively developed. For example, US Pat.
No. 8,378,851 discloses an electrophotographic photoreceptor having a charge transporting layer containing triarylpyrazoline, and US Pat. No. 3,871,880 discloses a condensate of a charge generating layer comprising a derivative of perylene pigment, 3-propylene and formaldehyde An electrophotographic photosensitive member comprising a charge transport layer comprising:

An electrophotographic photoreceptor using these organic photoconductive compounds is a function-separated type electrophotographic photoreceptor having a charge transport layer and a charge generation layer laminated in order to satisfy both electrical and mechanical properties. Often used as. On the other hand, as a matter of course, the electrophotographic photoreceptor is required to have sensitivity, electrical characteristics, and even optical characteristics according to the electrophotographic process applied.

In particular, in the case of a repetitively used electrophotographic photoreceptor, the surface of the electrophotographic photoreceptor is directly exposed to an electric or mechanical external force such as corona or direct charging, image exposure, toner development, transfer process, surface cleaning, etc. To be added,
Durability against them is also required.

More specifically, chemical deterioration due to ozone and nitrogen oxides during charging, discharge during charging, mechanical deterioration in which the surface is worn or scratched due to rubbing of a cleaning member, and electrical deterioration Durability against deterioration is required.

In particular, organic electrophotographic photoreceptors, which are often materially soft unlike inorganic electrophotographic photoreceptors, have poor durability against mechanical deterioration. Investigations on the effects of combination with a charge generating material and a charge transport agent have been advanced.

Further, in recent years, contact charging in which a voltage is applied directly to a charging member and a charge is applied to an electrophotographic photosensitive member as disclosed in JP-A-57-17826 and JP-A-58-40566. The method is becoming mainstream.

In these methods, a roller-shaped charging member made of a conductive rubber or the like is directly brought into contact with an electrophotographic photosensitive member to apply an electric charge. The amount of generated ozone is significantly smaller than that of a corona charging means or the like. On the other hand, about 80% of the current flowing through the charger by the corona charging means flows through the shield and is wasted. On the other hand, the contact charging has such advantages that it is very economical without waste.

However, contact charging has a drawback that charging stability is very poor due to charging by Paschen's law discharge. As a countermeasure, a so-called AC / DC charging system in which an AC voltage is superimposed on a DC voltage has been proposed (Japanese Patent Laid-Open No. 63-149668). In this system, the stability at the time of charging is improved. Since the AC voltage is superimposed, the amount of electric discharge on the surface of the electrophotographic photosensitive member is greatly increased, and a new problem arises in that the shaving amount of the electrophotographic photosensitive member is increased.

Under these circumstances, the technology has been progressing toward higher speed electrophotographic devices and longer life electrophotographic photosensitive members. On the other hand, the higher the speed of the electrophotographic photosensitive member and the smaller the cycle time (the time per second of the printing process of the electrophotographic photosensitive member (second)), the smaller the torque (mechanical load) for driving the electrophotographic photosensitive member. (In particular, the torque increases in a high-temperature or high-humidity environment due to environmental dependency), the power supply capacity of the drive motor increases, and when the cleaning member is in contact, the frictional force increases. The member is damaged or turned up (mainly blade-shaped). The more durable drums with less wear,
The tendency becomes more remarkable.

The term "high speed" as used herein means that the speed of a series of printing processes is high, and the speed (degree) generally means a process speed (paper transport speed). The printing process includes charging of the electrophotographic photosensitive member, formation of a latent image by exposure, development of a toner image on the latent image, transfer of the toner image to a printing medium such as paper, and cleaning of residual toner on the electrophotographic photosensitive member. And, if necessary, charge removal on the electrophotographic photoreceptor,
This refers to a series of flows of the electrophotographic photosensitive member (the print medium to which the toner has been transferred is output to the outside of the apparatus after the toner is fixed thereafter). When the electrophotographic photosensitive member has a cylindrical shape, the rotation speed is high (usually because paper conveyance speed / cylinder rotation speed).

As described above, if an organic electrophotographic photosensitive member is to be used in a simple system with a high-speed electrophotographic apparatus, a high-speed
There is a need to provide an electrophotographic apparatus and / or an electrophotographic photoreceptor adapted to a process with a small cycle time.

[0015]

SUMMARY OF THE INVENTION It is an object of the present invention to suppress an increase in the driving torque of an electrophotographic photosensitive member, which is a problem in mounting an organic electrophotographic photosensitive member in a high-speed electrophotographic apparatus, and to damage a cleaning member. And a process cartridge provided in the electrophotographic apparatus.

[0016]

According to the present invention, there is provided an electrophotographic apparatus for forming an image comprising a charging means, an exposing means, a developing means, a transferring means and a cleaning means for an electrophotographic photosensitive member by a contact charging system. The cycle time of the photoreceptor is less than 0.44 seconds / period, and a siloxane unit represented by the following general formula (1) is used as a binder resin for a surface layer of an electrophotographic photoreceptor having a photosensitive layer on a conductive support. An electrophotographic apparatus comprising the polymer and a charge width in the charging means and a transfer width in the transfer means satisfying the following expression (charge width-transfer width) ≦ 6.0 mm. A process cartridge provided in a photographic device is provided.

[0017]

Embedded image

In the formula, R ₁ and R ₂ are the same or different and each represents an alkyl group, an aryl group or an aralkyl group, and n represents an integer of 3 or more.

In the formula (1), examples of the alkyl group include a methyl group, an ethyl group, a t-butyl group and an n-propyl group, and examples of the aryl group include a phenyl group, a naphthyl group and an anthryl. Examples of the group include a benzyl group and a phenethyl group.

[0020]

Embodiments of the present invention will be described below in detail.

FIG. 1 is a schematic view of an example of an electrophotographic apparatus provided with the process cartridge of the present invention, and FIG. 2 illustrates the lengths of an electrophotographic photosensitive member, a charging member, a transfer member and a cleaning blade.

As shown in FIG. 1, the length configuration of the electrophotographic apparatus equipped with the charging roller 2 and the transfer roller 5 is to prevent charging failure and to prevent the transfer roller from being contaminated by toner (Japanese Patent Laid-Open No. 1-277269). Gazette), from the viewpoint of the rolling run-out tolerance of rollers and the cost / space saving
The configuration is such that the charging width of the charging roller is at least 7 mm or longer than the transfer width of the transfer roller (see FIG. 2).
Hereinafter, the terms “charging width” and “transfer width” are defined as “charging width: the effective charging width of the charging roller (the length of the portion that plays a major role in charging as shown in FIG. 2). The length of the part that plays a major role in transcription).

Therefore, on the electrophotographic photosensitive member, there are two portions a where a charging voltage is applied but a transfer voltage is not applied. The expression “(charging width−transfer width) ≦ 6.0 mm” indicates that the difference between the charging width and the transfer width is 6 mm or less.

When a normal resin is used as the surface layer of the electrophotographic photosensitive member, the frictional force between the electrophotographic photosensitive member and the member in contact with the electrophotographic photosensitive member is increased due to an increase in the process speed of the electrophotographic photosensitive member and a decrease in the cycle time. Due to the increase, the torque for driving the electrophotographic photoreceptor increases. If the increase in the torque is remarkable, the contact member may be damaged and the electrophotographic apparatus may not operate normally.

When the member for cleaning the transfer residual toner is a cleaning blade, the blade is broken (chipped), or when the blade cannot support the frictional force with the electrophotographic photosensitive member, the blade is turned up, The necessary operation as a photographic device cannot be performed.

What we have surprisingly found in this process is that the starting point of the blade breakage or curl is approximately the same, and the cleaning blade is taken out to confirm that part a in FIG. By doing
confirmed.

Although the reason is not clear, it is presumed that both the charging member and the transfer member are roller-shaped contact members.
The portion a on the electrophotographic photosensitive member is charged by the charging member, and is not subjected to contact (transfer) by the transfer member. Therefore, a discharge product (oxide, etc.) generated due to discharge deterioration of the electrophotographic photosensitive member surface due to charging. ), Compared to the transfer member contact part
Many as residues. For this reason, the part a has a larger surface energy than other parts, and the sliding property of the cleaning member may be small.

Under these circumstances, the use of a polymer containing a siloxane unit of the general formula (1) in the surface layer of the electrophotographic photosensitive member as a binder resin for the surface layer greatly reduces the damage and curling of the cleaning blade. Was found to be suppressed.

The reason is speculated that (1) the polymer containing a siloxane unit has water repellency (low surface energy) which is a characteristic of the siloxane unit, and (2) the siloxane unit is charged when charged. (3) Since the siloxane unit has the property of moving from the organic layer to the air layer in the fluidized bed, the surface of the electrophotographic photosensitive member may be locally heated at a high process speed. That the siloxane unit may migrate to the surface, which interacts to suppress the torque increase of the electrophotographic photoreceptor under short cycle time conditions,
Furthermore, it is considered that the blade breakage at the portion a in FIG. 2 is also suppressed.

However, in the case of an electrophotographic apparatus having a small cycle time, it is not possible to eliminate all cases of damage to the cleaning blade only by the structure of the surface layer of the electrophotographic photosensitive member. It is an essential requirement that the configuration of the electrophotographic apparatus of ≦ 6.0 mm be combined.

Recently, molding techniques (surface, etc.) such as a charging roller, which is a component for contact-charging the electrophotographic photosensitive member, and a transfer roller, which is a member for transferring a toner image on the electrophotographic photosensitive member to a transfer material (workpiece), are described. Conventionally, at least 7 to 10 mm or more has been ensured in consideration of tolerances due to improvements in accuracy of gears mounted on these parts and the accuracy of gears mounted on these parts. The difference between the two was also a factor in the progress of this study, as it became possible to use it without problems.

The reason why the threshold value exists where the difference between the charging width and the transfer width is 6.0 mm is unfortunately unknown, and is a finding obtained from the examination results.

In order to more effectively suppress such an increase in torque and breakage of the blade, the main component of the binder resin of the surface layer of the electrophotographic photosensitive member should contain a polyarylate resin and a polycarbonate Z-type resin. It is effective.

It is considered that the reason is that the polyarylate resin has a higher glass transition temperature (Tg) than the ordinary resin skeleton due to the basic skeleton and is resistant to heat-induced deformation. Similarly, it is conceivable that the polycarbonate Z type has a bisphenol skeleton that contributes to an increase in the glass transition temperature as a resin as compared with other bisphenol skeletons and is also resistant to heat-induced deformation.

Therefore, it is presumed that the increase in viscosity under high-speed conditions (the surface of the electrophotographic photosensitive member is probably at a high temperature) is suppressed, and the increase in viscoelastic torque (frictional force) due to frictional heat is suppressed.

Here, it is not clear from the findings obtained from the examination results that the effect is more apparent when the cycle time is less than 0.44 seconds / period, but the frequency dependence of the frictional force depends on the structure of the surface layer. It is inferred that there is a difference.

When the siloxane unit of the above formula (1) has, for example, a methyl group attached to a side chain, the siloxane unit imparts water repellency to the polymer (has a function of lowering the surface energy) to form a film. To provide slipperiness. Examples of the polymer containing a siloxane unit include the following copolymers (the number next to the structural formula is the molar ratio of each repeating unit).

[0038]

Embedded image

Examples of the structure of the polyarylate resin described above include JP-A-10-20519 and JP-A-1-20519.
The polyarylate resin is a thermoplastic resin having excellent mechanical abrasion resistance, as described in Japanese Patent Publication No. 0-20523 and the like. The structural units of these polyarylate resins are shown below, but are not limited thereto. In the examples, m and l indicate the degree of polymerization (molar ratio).

[0040]

Embedded image

[0041]

Embedded image

A polycarbonate resin is a binder widely used as a binder resin for an electrophotographic photosensitive member, particularly for a charge transport layer. Among them, a polycarbonate Z resin is a polymer having a Z-type bisphenol skeleton bonded to a carbonate structure and having a repeating structural unit represented by the following general formula (6).

[0043]

Embedded image

Hereinafter, the configuration of the electrophotographic photosensitive member used in the present invention will be described.

The electrophotographic photoreceptor according to the present invention will be described as an electrophotographic photoreceptor having a lamination type in which a charge transport layer and a charge generation layer are separated and a surface layer is a charge transport layer. However, when the charge generation layer is a surface layer, the structure of the present invention may be adopted as a case where a surface protective layer is provided on these layers or a single layer of the surface layer binder resin.

The support to be used may be any one having conductivity, such as a metal such as aluminum or stainless steel, or a metal provided with a conductive layer, paper and plastic. The shape may be a sheet or a cylinder. No.

A conductive layer may be provided for covering the scratches on the support. This can be formed by dispersing a conductive powder such as carbon black or metal particles in a binder resin. The thickness of the conductive layer is preferably 5 to 40 μm,
In particular, 10 to 30 μm is preferable.

Further, an intermediate layer having an adhesive function and a barrier function is provided thereon. Examples of the material of the intermediate layer include polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, casein, polyurethane, and polyether urethane. These are dissolved in an appropriate solvent and applied. The thickness of the intermediate layer is 0.05 to
5 μm is preferred, and particularly preferably 0.3 to 1 μm.

The charge generation layer is formed on the intermediate layer.
The charge generation layer used in the present invention is formed by applying and drying a coating liquid in which a charge generation material and a binder resin are dispersed in a solvent. In the case of the function separation type, the charge generation layer is formed by dispersing the charge generation material together with a binder resin and a solvent using a homogenizer, an ultrasonic dispersion, a ball mill, a vibration ball mill, a sand mill, an attritor, a roll mill, and a liquid collision type high-speed dispersion machine. Disperse well. Examples of the charge generation material used here include pyrylium, thiapyrylium dyes, phthalocyanine, anthantrone, dibenzopyrene quinone, trisazo, cyanine, disazo, monoazo, indigo, quinacridone, and asymmetric quinocyanine pigments. As the binder resin, for example, polyester resin, polyacrylic resin, polyvinyl carbazole resin,
Phenoxy resin, polycarbonate resin, polystyrene resin, polyvinyl acetate resin, polysulfone resin, polyarylate resin, vinyldene chloride, polyvinyl benzal resin, polybutyral resin, and the like are mainly used. The ratio of pigment to binder resin is 1 / 0.1 to 1/1
0 is preferred, and more preferably 1/1 to 3/1.
The thickness of the charge generation layer formed by coating and drying the dispersion is preferably 5 μm or less, and particularly preferably 0.1 to 2 μm.

The charge transport layer is formed by coating / drying a coating liquid in which a charge transport material and a polymer containing a siloxane unit of the present invention as a binder resin are dissolved in a suitable solvent for dissolving them. Formed. Examples of the charge transport material to be used include low molecular compounds such as triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, triarylmethane compounds, and thiazole compounds. As the binder resin of the charge transport layer, in addition to using the polymer containing the siloxane unit of the present invention as a single product, a polyarylate resin or a polycarbonate resin may be blended, or other resins, for example, a polyacrylate resin, a polyester resin , A polystyrene resin, a styrene-acrylonitrile copolymer resin, a polymethacrylate resin, a styrene-methacrylate copolymer resin, or the like may be further mixed. The charge transporting material is combined with a binder resin in an amount of 0.5 to 2 times the amount thereof, and is coated and dried to form a charge transporting layer. The thickness of the charge transport layer is preferably 5 to 40 μm, and particularly preferably 15 to 30 μm.

In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer. As a plasticizer,
What is used as a plasticizer for general resins such as dibutyl phthalate and dioctyl phthalate can be used as it is, and its use amount is suitably about 30% by mass or less based on the binder resin. As the leveling agent, silicone oils such as dimethyl silicone oil and methyl phenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in a side chain are used. The following are appropriate:

In the present invention, an antioxidant can be added for the purpose of improving environmental resistance, particularly for the purpose of preventing a decrease in sensitivity and an increase in residual potential. The antioxidant may be added to any layer containing an organic substance, but good results can be obtained by adding it to a layer containing a charge transporting material.

Examples of preferably used compounds include:
Examples include, but are not limited to, those having a hindered amine structural unit or a hindered phenol structural unit, or those having both, an organic phosphorus compound, an organic sulfur compound, a hydroquinone compound, and a phenylamine compound. Not something.

(1) Examples of compounds having a hindered phenol structural unit

[0055]

Embedded image

(2) Examples of compounds having hindered amine structural units

[0057]

Embedded image

(3) Examples of organic phosphorus compounds

[0059]

Embedded image

(4) Examples of organic sulfur compounds S (C ₂ H ₄ COOC ₁₂ H ₂₅ ) ₂ (7-8) S (C ₂ H ₄ COOC ₁₄ H ₂₉ ) ₂ (7-9)

(5) Examples of hydroquinone compounds

[0062]

Embedded image

These compounds are known as antioxidants for rubbers, plastics, oils and the like, and are readily available as commercial products, but their purity is sufficiently increased so as not to adversely affect the electrophotographic properties. There is a need. The addition amount of the antioxidant in the present invention is preferably 0.1 to 100 parts by mass, particularly preferably 2 to 3 parts by mass, per 100% by mass of the charge transporting material.
0 parts by mass is preferred.

Next, the configuration near the electrophotographic photosensitive member will be described.

FIG. 1 shows an example of a contact charging type electrophotographic apparatus, which is a transfer type copying machine or a printer, in which an electrophotographic photosensitive member 1, a charging roller 2, a developing device 4 and a cleaning blade 8 are formed in a process cartridge frame. This is an example of the case of a cartridge system incorporated in the body 9.

The electrophotographic photosensitive member 1 is of a drum type. The electrophotographic photosensitive member 1 is rotationally driven at a predetermined peripheral speed (≒ process speed) in a clockwise direction indicated by an arrow.

The charging roller 2, which is a contact charging member as a charging means, rotates following the rotation of the electrophotographic photosensitive member 1 pressed against the charging roller, and rotates by a bias power supply (not shown).
A DC voltage on which an AC voltage is superimposed is applied. The charging roller 2 uniformly charges the peripheral surface of the electrophotographic photosensitive member 1 to a predetermined polarity / potential. The electrophotographic photoreceptor 1
Exposure light 3 of the target image information is applied to the charging processing surface by exposure means (not shown) (laser beam scanner or the like), and an electrostatic latent image corresponding to the target image information is formed on the surface of the electrophotographic photosensitive member 1.

The formed electrostatic latent image is visualized as a transferable particle image (toner image) with charged particles (toner) in the developing device 4 by normal development or reverse development.

Next, the toner image is transferred to the electrophotographic photosensitive member 1.
The transfer material 6 is transferred to a transfer material 6 fed between the transfer member 5 and the transfer roller 5 which is in pressure contact with the electrophotographic photosensitive member. At this time, a bias voltage having a polarity opposite to the charge retained in the toner is applied to the transfer roller 5 from a bias power supply (not shown).

The transfer material 6 to which the toner image has been transferred is separated from the surface of the electrophotographic photosensitive member 1 and is conveyed to a fixing roller 7 to undergo a toner image fixing process.

The surface of the electrophotographic photosensitive member after the transfer of the toner image is
The cleaner (cleaning blade) 8 removes extraneous matter such as toner remaining after transfer, and the entire process ends.

[0072]

The present invention will be described below in more detail with reference to specific examples. In the examples, "parts" are parts by mass.

(Example 1) Under normal temperature / humidity, 30φ × 3
A 58 mm aluminum cylinder was used as a support, and a coating liquid composed of the following materials was applied on the support by a dipping method, and was thermally cured at 140 ° C. for 30 minutes to form a film having a thickness of 15 mm.
A μm conductive layer was formed.

Conductive pigment: SnO ₂ coated barium sulfate 10 parts Resistance adjusting pigment: titanium oxide 2 parts Binder resin: phenol resin 6 parts Leveling material: silicone oil 0.001 part Solvent: methanol / methoxypropanol 0.2 /0.8 20 parts

Next, a solution obtained by dissolving 4.5 parts of N-methoxymethylated nylon and 1.5 parts of copolymerized nylon in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol was applied thereon by dipping. And an intermediate layer having a thickness of 0.6 μm.

Next, the characteristic X-ray diffraction Bragg angles (2θ ± 0.2 °) of CuKα are 9.0 °, 14.2 °, 23.
3.24 parts of oxytitanium phthalocyanine (TiOPc) having strong peaks at 9 ° and 27.1 °, 0.36 part of an azoxy pigment of the following structural formula (8) and polyvinyl butyral (trade name: Eslek BX-1, Sekisui Chemical) (Manufactured by Kogyo Co., Ltd.) was dissolved in 110 parts of cyclohexanone, and then dissolved in a high-pressure disperser (Microfluitizer, Microfl).
uidics), and then the following structural formula (9)
0.66 parts of sulfur-based additive and ethyl acetate 250
The resulting mixture was added to prepare a dispersion for a charge generation layer. This was applied by an immersion method to form a charge generation layer having a thickness of 0.3 μm.

[0077]

Embedded image

[0078]

Embedded image

Next, the charge transport material 9 of the following structural formula (10)
Department

[0080]

Embedded image

Further, a copolymer containing 8 parts of a polyarylate resin (weight average molecular weight Mw = 110,000) represented by the above formula (5-3) and a siloxane unit represented by the above formula (4-2) (Viscosity average molecular weight Mv = 40,000) 2 parts were dissolved in a mixed solvent of 33 parts of dimethoxymethane / 60 parts of monochlorobenzene to prepare a coating liquid for a charge transport layer.

Coating with this paint by dipping method (constant coating speed)
Then, the resultant was dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 25 μm (near the center).

Next, the evaluator will be described. The equipment is
Canon LBP-950− process speed 144.
The power supply, which was set at 5 mm / sec, was modified and the process speed was increased to 236 mm / sec (the cycle time was 0.40 sec / period). The one modified 5 times and the process cartridge were used. At this time, the transfer roller was replaced with one having a length (transfer width) of 306 mm, and the difference from the charge width of the charging roller (Δ = charge width−transfer width) was set to 2 mm.

First, the electrophotographic photosensitive member obtained above was mounted on the process cartridge, and then evaluated at 30 ° C. /
After printing 20,000 sheets of letter paper with intermittent single-sided printing on a letter image with a printing rate of about 3% in a temperature and humidity environment of 70% RH, disassemble the process cartridge and check the damage status of the cleaning blade. Table 1 shows the results.
(○: No abnormality, Δ: Minor blade chipping, ×: Blade chipping, XX: Blade turned up before reaching 20,000 sheets, evaluation stopped)

Thereafter, the charging roller, which is a component for charging the electrophotographic photosensitive member, is removed from the cleaner unit of the process cartridge which has been durable (the cleaning blade is in contact with the electrophotographic photosensitive member). Mounted on a device that can measure the rotational torque of the photoreceptor (the rotating shaft of the electrophotographic photoreceptor is the shaft that penetrates the center of the cylinder as well as the penetrating shaft of the electrophotographic photoreceptor of the cleaner unit) and has an environment of 35 ° C / 80% RH. 5 process speeds shown in Table 1 from 150 to 300 mm / sec.
At 63 to 0.31 seconds / cycle), the rotational torque of the drum was measured for each (measured one minute after driving). Table 1 shows the results.

Example 2 The structure of the electrophotographic photosensitive member and the method of evaluating the manufactured electrophotographic photosensitive member were evaluated in the same manner as in Example 1, except that the structure of the charge transport layer was changed to the following structure. The results are shown in Table 1.

The charge-transporting layer constituting the charge-transporting layer is composed of only 9 parts of the compound of the formula (10), 8.1 parts of the formula (10) and 0.9 parts of the following formula (11). The same electrophotographic photosensitive material as in Example 1 except that 8 parts of the polyarylate resin represented by 5-3) was replaced with 8 parts of a polycarbonate Z-type resin (trade name: Z400, manufactured by Mitsubishi Engineering-Plastics Corporation). Body.

[0088]

Embedded image

Example 3 The structure of the electrophotographic photosensitive member and the method of evaluating the produced electrophotographic photosensitive member were evaluated in the same manner as in Example 2, except that the structure of the charge transport layer was changed to the following structure. The results are shown in Table 1.

The charge transporting layer was changed except that the resin composition was changed from 8 parts to 4 parts of polycarbonate resin Z type (Z400 described above) and 4 parts of polyarylate (Mw = 110,000) of the formula (5-3). This is the same electrophotographic photoreceptor as in Example 2.

Example 4 The transfer roller was replaced with one having a length (transfer width) of 302 mm, the difference from the charge width of the charging roller (Δ = charge width-transfer width) was set to 6 mm, and the charge was changed. The configuration of the electrophotographic photoreceptor and the method of evaluating the produced electrophotographic photoreceptor were evaluated in the same manner as in Example 2 except that the configuration of the transport layer was changed to the following configuration. The results were shown in Table 1.

The resin constituting the charge transport layer is Z40
0 is 8 parts and the compound of the formula (4-2) is 2 parts, and the polyarylate of the formula (5-3) (Mw = 110,000) 5
Part of a polycarbonate resin Z type (trade name: Z200, manufactured by Mitsubishi Engineering-Plastics Corporation) and a copolymer containing a siloxane unit represented by the above formula (4-2) (viscosity average molecular weight Mv = 40,000) and a silicone powder lubricant (trade name: Aron GS)
-101CP, manufactured by Toagosei Chemical Industry Co., Ltd.), and the same electrophotographic sensitization as in Example 2 except that dimethoxymethane 23 parts / monochlorobenzene 41.5 parts and the film thickness were 26 μm. Body.

(Example 5) The transfer roller was replaced with one having a length (transfer width) of 303 mm, the difference from the charge width of the charging roller (Δ = charge width-transfer width) was set to 5 mm, and the charge was changed. The configuration of the electrophotographic photoreceptor and the method of evaluating the produced electrophotographic photoreceptor were evaluated in the same manner as in Example 4 except that the configuration of the transport layer was changed to the following configuration, and the results were described in Table 1.

In the resin composition constituting the charge transport layer,
The polycarbonate resin of Example 4 (trade name: Z200,
The same electrophotographic photosensitive member as in Example 4 except that 4 parts of Mitsubishi Engineering-Plastics Co., Ltd. were changed to 4 parts of Z400 (trade name, manufactured by Mitsubishi Engineering-Plastics Corporation) and the film thickness was changed to 24 μm. Body.

Example 6 The structure of the electrophotographic photosensitive member and the method of evaluating the produced electrophotographic photosensitive member were evaluated in the same manner as in Example 4, except that the structure of the charge transport layer was changed to the following structure. The results are shown in Table 1.

The charge transport material constituting the charge transport layer was 7.2 parts of the charge transport material of the above formula (10) and 0.8 parts of the charge transport material of the above formula (11). Furthermore, the resin composition constituting the charge transport layer is a polycarbonate resin (trade name: Z-4)
8.5 parts, manufactured by Mitsubishi Engineering-Plastics Co., Ltd.), 1 part of a silicone modified copolymerized polycarbonate resin (Mv = 40,000) represented by the following formula (12), and 1 part by the above formula (4-2) 0.5 part of a silicone-modified polycarbonate resin (Mv = 40,000) and 0.18 part of a silicone powder lubricant (trade name: Alon GS-101CP, manufactured by Toagosei Chemical Industry Co., Ltd.) were added. , Film thickness 2
This is the same electrophotographic photosensitive member as in Example 4, except that the thickness was changed to 8 μm.

[0097]

Embedded image

Example 7 The transfer roller was replaced with a roller having a length (transfer width) of 304 mm, the difference from the charge width of the charging roller (Δ = charge width−transfer width) was set to 4 mm, and the charge was changed. The configuration of the electrophotographic photoreceptor and the method of evaluating the produced electrophotographic photoreceptor were evaluated in the same manner as in Example 2 except that the configuration of the transport layer was changed to the following configuration. The results were shown in Table 1.

The resin constituting the charge transport layer is represented by the above formula (6)
8 parts of the polycarbonate Z-type resin of the formula (4-2) 2
Was replaced by the following formula (4-4) (Mv = 50,000) 10
Parts, and the solvent for dissolving them is dichloromethane / chlorobenzene = 1/1 (the mass ratio and amount are the same 9 parts).
The same electrophotographic photoreceptor as in Example 2 except that only 3 parts) was used.

[0100]

Embedded image

(Comparative Example 1) The structure of the electrophotographic photosensitive member and the method of evaluating the produced electrophotographic photosensitive member were evaluated in the same manner as in Example 2, except that the structure of the charge transport layer was changed to the following structure. The results are shown in Table 1.

The resin constituting the charge transport layer is represented by the formula (6)
What was 8 parts of the polycarbonate Z-type resin and 2 parts of the formula (4-2) was replaced with polycarbonate Z-type (the above-described Z-40).
0) The same electrophotographic photoreceptor as in Example 2, except that only 10 parts were replaced and the solvent composition was changed to 23 parts of dimethoxymethane / 41.5 parts of monochlorobenzene.

Comparative Example 2 The structure of the electrophotographic photosensitive member and the method of evaluating the produced electrophotographic photosensitive member were evaluated in the same manner as in Example 2 except that the structure of the charge transport layer was changed to the following structure. The results are shown in Table 1.

The resin constituting the charge transport layer is represented by the above formula (6)
Example 2 except that 8 parts of the polycarbonate Z-type resin and 2 parts of the formula (4-2) were replaced with only 10 parts of the polyarylate resin (Mw = 130,000) of the above formula (5-3).
This is the same electrophotographic photoreceptor.

(Comparative Example 3) The transfer roller was replaced with one having a length (transfer width) of 301 mm, the difference from the charge width of the charging roller (Δ = charge width-transfer width) was set to 7 mm, and the charge was changed. The configuration of the electrophotographic photoreceptor and the method of evaluating the produced electrophotographic photoreceptor were the same as those described above except that the solid component configuration (charge transport material, binder resin and additives, and film thickness) of the transport layer was changed to the following configuration.
Evaluation was performed in the same manner as in Example 2, and the results are shown in Table 1.

The polyarylate of the above formula (5-6) (Mw = 120,000, where m / n = 1/1) was obtained from 8 parts of the polycarbonate Z-type resin of the above formula (6) constituting the charge transport layer.
1) The same electrophotographic photoreceptor as in Example 2 except that 8 parts were used.

[0107]

[Table 1]

[0108]

As described above, according to the present invention, in a high-speed electrophotographic apparatus having a short cycle time, a polymer containing a siloxane unit is used for a surface layer of an organic electrophotographic photoreceptor, When the charging width and the transfer width of the apparatus satisfy the following formula (charge width-transfer width) ≦ 6.0 mm, the cycle time is particularly 0.44.
In the process of less than seconds / period, an increase in torque is suppressed, and damage to the cleaning member and the like is prevented, and as a result, a small-diameter, small-sized, low-cost electrophotographic apparatus and a configuration of a process cartridge can be provided. In addition, the required driving energy of the electrophotographic photosensitive member can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of an electrophotographic apparatus provided with a process cartridge of the present invention.

FIG. 2 is an arrangement diagram of an electrophotographic photosensitive member, a charging roller, a transfer roller, and a cleaning blade.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Charging roller 3 Exposure light 4 Developing device 5 Transfer roller 6 Transfer material 7 Fixing roller 8 Cleaning blade 9 Cartridge frame 10 Cartridge guide

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) G03G 21/10 G03G 21/00 318 F term (reference) 2H068 AA03 AA13 AA21 BB26 BB27 BB33 FA00 FC01 2H071 BA03 BA04 BA13 DA06 DA08 DA13 DA15 2H134 GA01 GB01 HD01 KG01 KG04 KH02 KH11 KH15 2H200 FA09 FA15 FA19 GA16 GA23 GA34 GA44 GB12 HA02 HB12 HB20 HB22 JA02 LA38

Claims (8)

[Claims] 1. An electrophotographic apparatus for forming an image comprising a charging means, an exposure means, a developing means, a transfer means and a cleaning means for an electrophotographic photosensitive member by a contact charging system, wherein the cycle time of the electrophotographic photosensitive member is zero. .44 seconds /
A polymer containing a siloxane unit represented by the following general formula (1) as a binder resin for a surface layer of an electrophotographic photoreceptor having a photosensitive layer on a conductive support, which is shorter than the period, (Wherein R ₁ and R ₂ are the same or different and are an alkyl group, an aryl group or an aralkyl group, and n represents an integer of 3 or more). An electrophotographic apparatus characterized by satisfying (charge width-transfer width) ≦ 6.0 mm. 2. The electrophotographic apparatus according to claim 1, wherein the structure of the polymer containing the siloxane unit is represented by the general formula (2). Embedded image (Wherein the molar ratio of 1 / m ranges from 9/1 to 99/1, n
Is an integer of 3 to 50) 3. The electrophotographic apparatus according to claim 1, wherein the surface layer of the electrophotographic photosensitive member contains a polyarylate resin. 4. The electrophotographic apparatus according to claim 3, wherein the structure of the polyarylate resin is represented by the following general formula (3). Embedded image 5. The electrophotographic apparatus according to claim 1, wherein the surface layer of the electrophotographic photosensitive member contains a polycarbonate Z resin. 6. The electrophotographic apparatus according to claim 1, wherein the charging member and the transfer member are roller-shaped contact members.
An electrophotographic apparatus according to any one of the above. 7. The electrophotographic apparatus according to claim 1, further comprising cleaning means for recovering the toner remaining on the electrophotographic photosensitive member after the transfer step by using a blade-shaped member.
The electrophotographic apparatus according to any one of the above. 8. An electrophotographic photosensitive member according to claim 1, charging means for charging said electrophotographic photosensitive member, and developing for developing said electrophotographic photosensitive member on which an electrostatic latent image is formed with toner. Means, and at least one means selected from the group consisting of a cleaning means for collecting the residual toner on the electrophotographic photosensitive member after the transfer step, and are integrally supported and detachably attached to the electrophotographic apparatus main body. And process cartridge.