JP6303801B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, a plotter, and a multifunction machine provided with at least one of them.

In an image forming apparatus that forms a toner image on an image carrier (latent image carrier) and transfers it to transfer paper, a technique of applying a lubricant to the surface of the image carrier to protect the surface of the image carrier is widely used. ing.
If the surface protection function by applying the lubricant is not provided, an additive contained in the toner, a resin component of the toner, a wax component, a discharge product, and the like may adhere to the surface of the image carrier and an abnormal image may be generated.
Many of the substances adhering to the surface of the image carrier are derived from the toner. In particular, a phenomenon that the external additive contained in the toner is released from the toner and adheres to the surface of the image carrier is likely to occur.
Therefore, reducing the amount of external additive to the toner is a countermeasure, but the toner external additive plays various important roles such as toner protection function and charging function. It can be said that it is not an efficient measure.
There is a method in which the amount of free additive is measured and managed for each toner lot, and lots with a free amount above a certain level are not shipped. However, the yield is worse, so efficiency is also increased in terms of cost increase and environmental impact. Not right.

When the adhered component is fixed and grows in the rotation direction of the image carrier, streaky white spots may be generated in the sub-scanning direction.
Therefore, the surface protection function of the image carrier by applying the lubricant is an excellent technique, but it is difficult to always maintain the lubricant applicability uniformly.
In general, in a lubricant application device, a solidified bar is made into a powder by rubbing (scraping) with a brush or the like, and the powder lubricant is applied to the image carrier. There are many systems in which the lubricant is uniformly applied to the surface by leveling with a lubricant application blade.
However, the amount of the lubricant scraped from the lubricant bar by the brush is likely to fluctuate due to disturbances such as temperature and humidity, and the amount of scraping tends to decrease in a high temperature and high humidity environment.

In order to increase the amount of scraping, it is conceivable to increase the hardness and rotation speed of the brush. However, the amount of scraping becomes too large due to rapid environmental fluctuations and variations.
If this happens, abnormalities such as contamination of the charging roller due to excessive application of the lubricant, or contamination of the developing device due to the lubricant being mixed into the developing device may occur. Problem arises.
For this reason, it is not always possible to keep a large amount of lubricant applied, and the design is often aimed at a central amount of application in consideration of a width that varies due to disturbance.

By the way, since it is desirable to install the lubricant application device in a region where no toner exists on the surface of the image carrier, it is often installed downstream of the cleaning device in the rotation direction of the image carrier.
However, when the cleaning device is deteriorated, the transfer residual toner may slightly pass through the cleaning device.
In such a case, the transfer residual toner that has passed through prevents the lubricant from being applied, and in the case where the amount of applied lubricant is reduced due to the influence of disturbance, the above-mentioned streaky white spots are generated. There is a possibility that.
Therefore, the cleaning device is required to be highly durable. However, in the case where images with a high image area ratio are continuously formed, it is difficult to sufficiently exhibit the cleaning performance, and the transfer residual toner slips through. Can happen.

The reason why the cleaning performance may not be sufficiently exhibited when images with a high image area ratio continue is as follows.
For example, in a mechanism that scrapes transfer residual toner with a cleaning blade and collects it as waste toner, if a large amount of transfer residual toner is constantly input to the contact portion between the cleaning blade and the image carrier, the waste toner recovery catches up. Absent.
In such a case, the transfer residual toner stays at the contact portion between the cleaning blade and the image carrier, and it becomes easy to slip through.

Therefore, measures are taken such as performing an operation of once stopping the image forming operation and continuing to rotate the image carrier.
That is, it is effective to control the interval mode so that the transfer residual toner staying at the contact portion between the cleaning blade and the image carrier can be collected as waste toner.
Increasing the distance between the papers is also an effective measure because it reduces the image area ratio per traveling area of the image carrier.

In addition, with respect to the above-described problem, it is possible to avoid a situation in which the above-described streak-like white spots are generated by setting the cleaning device to have a short set life or mounting an expensive material / mechanism.
However, despite the fact that images with a high image area ratio are continuously formed are relatively rare, therefore, the set life of the cleaning device is set short, or expensive materials and mechanisms are mounted. Is inefficient.
As described above, in the case where the external additive of the toner adheres to the image carrier, if the amount of the external additive is small, even if the amount of applied lubricant is reduced due to the influence of the disturbance, the -Like white spots are unlikely to occur.
For this reason, it can be said that the state (property) of the external additive of the toner is an important factor in performing control so that streak-like white spots are not generated.

Regarding a technique for stably applying a conventional lubricant, Patent Document 1 discloses a technique for detecting an image area ratio and changing a distance between sheets in a low linear velocity mode.
Patent Document 2 discloses a technique that includes a lubricant application mode and controls the lubricant application amount based on information on the image area ratio and the number of printed sheets.
Japanese Patent Laid-Open No. 2003-260688 discloses that image printing is interrupted in accordance with image area ratio information, temperature / humidity information, and travel distance information of the image carrier, and idle rotation is performed while toner supply to the image carrier is prohibited. Techniques for cleaning the body surface are disclosed.

As in the technique described in Patent Document 1, it is important to detect the image area ratio and reflect it in the lubricant application control. However, the lubricant stable application performance contributes to the deterioration state of the cleaning device and the temperature and humidity. Is known to be very large, which is insufficient and wasteful for control.
Also in the technique described in Patent Document 2, as in the technique described in Patent Document 1, a very contributing factor such as temperature and humidity information is not reflected in the control.
Although component deterioration is detected in a pseudo manner based on the number of printed sheets, component deterioration is not determined by the number of printed sheets and is insufficient.
In addition, when the lubricant application mode is executed, it is necessary to temporarily stop the printing operation and cause it to idle, so that the usability is deteriorated such that the time until completion of printing is long in spite of a printing command with a small number of sheets. There is a fear.

Even in the technique described in Patent Document 3, it can be said that the deterioration information of the cleaning device is a factor that contributes very much to the maintenance of the surface property of the image carrier, and it is not sufficient that the information is not reflected in the control.
Furthermore, since the information on the external additive of the toner to be used is an important element in the control for suppressing the adhesion of the external additive to the image carrier as described above, it is not sufficient that the information is not reflected in the control. It can be said that there is.
Similar to the technique described in Patent Document 2, temporarily stopping the printing operation and causing it to idle may cause a deterioration in usability such as a long time to completion of printing even for a printing command with a small number of sheets.
It is desirable that the lubricant application mode and the image carrier surface cleaning operation be performed in parallel with the printing operation rather than stopping the printing operation.

By the way, in the case of a solid image, the amount of adhesion of the solid area on the photosensitive drum is the largest.
The target adhesion amount is designed so that the image density and color are appropriate, but the optimum target adhesion amount varies depending on the type of transfer paper.
There is a glossy coated paper whose surface is coated with a paper type generally called plain paper.
It is known that even if the amount of toner attached per unit area is the same between plain paper and coated paper, the image density and color are different, and the coated paper has a higher image density.
Therefore, when the image forming apparatus detects that the coated paper is used as the transfer paper, the target image adhesion amount per unit area at the time of solid image formation is changed to a small amount so that an appropriate image quality corresponding to the type of the transfer paper is obtained. There is technology to get.

However, when the target adhesion amount is changed in accordance with the type of transfer paper, the transfer residual toner amount also changes in accordance with the target adhesion amount, so that the level of occurrence of streaky white spots also changes.
When some of these conditions are overlapped, the above-mentioned streaky white spots may occur.

  The present invention was devised in view of such a current situation, and provides an image forming apparatus capable of appropriately preventing the occurrence of abnormal images such as streaky white spots in terms of cost and usability without waste. Is its main purpose.

  In order to achieve the above object, the present invention provides an image carrier, latent image forming means for forming an electrostatic latent image on the image carrier based on image information, and a latent image on the image carrier. A developing device that attaches toner to form a visible image, a transfer device that transfers the visible image to a recording medium, and a toner remaining on the image carrier after the transfer are removed by a blade that contacts the image carrier. A cleaning device; a lubricant application device that applies a lubricant on the image carrier; an environment detection sensor that detects an installation environment of the image forming device; and a toner container that contains toner to be replenished to the developing device; An image area ratio detecting means for detecting an image area ratio of the visible image per predetermined image forming operation amount, and an image area ratio detected by the image area ratio detecting means; The cleaning And the amount of location, and the environment information detected by the environment detection sensor, in accordance with the toner information of the toner containing body, and changes the image formation interval during continuous image formation.

  According to the present invention, the occurrence of abnormal images such as streak-like white spots can be suppressed with high accuracy without stopping the image forming operation, and can be appropriately prevented without waste in terms of cost and usability.

1 is a schematic configuration diagram of a printer as an image forming apparatus according to an embodiment of the present invention. It is a detailed view of a process unit (process cartridge). It is a division figure of the installation environment based on temperature and humidity information. It is a figure which shows the relationship between the average image area rate for calculating | requiring a CPM down rate, and the value of (alpha). It is a figure which shows the relationship between the temperature / humidity division for calculating | requiring a CPM down rate, and the value of (beta). It is a figure which shows the relationship between the usage-amount of a drum cleaning blade for calculating | requiring a CPM down rate, and the value of (gamma). FIG. 6 is a diagram illustrating a relationship between a free amount of SiO _{2 in} a toner lot stored in an ID chip of a toner bottle and a value of ε. It is a figure which shows CPM after CPM down and the distance between each paper size when CPM down rate D = 20%. It is a figure which shows the comparison with the conventional example of the lifetime of the drum cleaning blade in Example 1. FIG. It is a figure which shows the relationship between the value of (gamma) of the drum cleaning blade usage-amount in Example 2, and a lubricant application brush usage-amount. It is an image figure of image area ratio calculation. It is a figure which shows the comparison with Example 1 of the CPM down rate in Example 3. FIG. It is a figure which shows the relationship between the value of (gamma) of the usage-amount of a drum cleaning blade in Example 4, and a lubricant application brush travel distance. It is a graph which shows the relationship between a travel distance ratio and the number of image formation (PPJ). FIG. 10 is a diagram illustrating a comparison with the second embodiment regarding an image formation count value threshold value that shifts to a CPM down mode according to a fourth embodiment. It is a figure which shows the relationship between the value of (gamma) of the drum cleaning blade traveling distance and lubricant application brush traveling distance in Example 5. FIG. FIG. 10 is a diagram illustrating a comparison with the first embodiment regarding an image formation count value threshold value for shifting to a CPM down mode according to a fifth embodiment. It is a figure which shows the comparison with Example 1 of the CPM down rate in Example 6. FIG. FIG. 10 is a diagram illustrating a relationship between a transfer sheet type and a value of δ for obtaining a CPM down rate in Example 7. FIG. 10 is a diagram illustrating a calculation formula for an average image area ratio for each process unit according to an eighth embodiment. FIG. 3 is a perspective view illustrating an integrated configuration of a toner bottle and an ID chip. FIG. 22 is a perspective view showing another example of the integrated configuration shown in FIG. 21.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, a basic configuration of an electrophotographic printer as an image forming apparatus according to the present embodiment will be described.
FIG. 1 is a schematic configuration diagram of the printer 1. A temperature / humidity sensor 4 as an environment detection sensor is disposed below the printer main body (image forming apparatus main body) 2, and the temperature and humidity of the installation environment of the image forming apparatus are detected by the temperature / humidity sensor 4.
The printer 1 includes four process units 6Y, 6C, 6M, and 6K for yellow, cyan, magenta, and black (hereinafter referred to as Y, C, M, and K) as image forming means.
These use Y, C, M, and K toners of different colors as image forming substances for forming an image, but the other configurations are the same.

The process unit 6Y for generating a Y toner image will be described as an example. As shown in FIG. 2, the process unit 6Y includes a photoconductor unit 8 and a developing device 10 as a developing unit.
The photosensitive unit 8 and the developing device 10 are detachably attached to the printer main body.
When the black single color mode for printing only black single color is selected, only the K process unit 6K operates to perform printing.

The photoconductor unit 8 includes a photoconductor drum 12 as an image carrier and a drum cleaning device 14 as a cleaning device that removes and collects transfer residual toner and the like attached (residual) on the photoconductor drum after transfer. Yes.
The drum cleaning device 14 includes a drum cleaning blade 14a as a blade, a recovery screw 14b, and the like.
The photoconductor unit 8 includes a lubricant applying device 16 for setting the surface friction coefficient of the photoconductor drum to a predetermined value, and a charging device 18 for uniformly charging the photoconductor drum.

The lubricant application device 16 includes a lubricant 20 made of zinc stearate formed in a block shape or a bar shape, a lubricant application brush 22 as an application brush that scrapes in contact with the lubricant 20, and a lubricant application blade. 24.
The lubricant application blade 24 is a member for uniformly applying the lubricant onto the photosensitive drum.
The charging device 18 includes a charging roller 26 for uniformly charging the photosensitive drum, and a charging roller cleaner 28 that contacts the charging roller 26.
The charging roller 26 uniformly applies a charging bias obtained by superimposing a DC voltage on an AC voltage from a charging bias applying unit (not shown) to the surface of the photosensitive drum that is rotated clockwise in the drawing by a driving unit (not shown). Charge.

The developing device 10 includes a first developer accommodating portion 32 in which a first conveying screw 30 is disposed, and a second developer accommodating portion 36 in which a second conveying screw 34 is disposed.
On the lower surface of the first developer accommodating portion 32, a toner concentration sensor 38 is installed as a toner concentration detecting means including a magnetic permeability sensor.
The mixing ratio of the carrier particles, which are magnetic materials, and the toner is calculated from the magnetic permeability, and the toner is replenished as necessary from a toner replenishing device (not shown) so as to obtain a predetermined toner concentration.
The first conveying screw 30 is rotationally driven by a driving means (not shown), and conveys the developer in the first developer accommodating portion 32 from the back side to the near side in the direction orthogonal to the drawing.
The developer enters the second developer accommodating portion 36 through a communication port (not shown) provided in the partition wall between the first developer accommodating portion 32 and the second developer accommodating portion 36.

The second conveying screw 34 in the second developer accommodating portion 36 is rotationally driven by a driving means (not shown) to convey the developer from the front side to the back side in the drawing.
Above the second conveying screw 34, a developing sleeve (developing roller) 40 as a developer carrying member is disposed in a posture parallel to the second conveying screw 34, and the developing sleeve 40 rotates counterclockwise in the figure. Driven.
The developing sleeve 40 is made of a pipe made of a nonmagnetic material (aluminum), and the surface is roughened by sandblasting.
A magnet (not shown) is disposed inside the developing sleeve 40, and a part of the developer conveyed by the second conveying screw 34 is pumped up to the surface of the developing sleeve by the magnetic force generated by the magnet.
The developer thus pumped up is transported to the developing region facing the photosensitive drum after the layer thickness is regulated by the doctor blade 42 disposed so as to maintain a predetermined gap with the developing sleeve 40.

By a developing bias applied to the developing sleeve 40 from a developing bias applying means (not shown), toner is attached to the electrostatic latent image formed on the photosensitive drum to form a toner image as a visible image.
The developer that has consumed toner by development is returned to the second conveying screw 34 as the developing sleeve 40 rotates. Then, when it is conveyed to the far end in the figure, it returns into the first developer accommodating portion 32 through a communication port (not shown).
The detection result of the magnetic permeability of the developer by the toner concentration sensor 38 is sent to a control unit (not shown) as a voltage signal.
Since the magnetic permeability of the developer has a correlation with the toner concentration of the developer, the toner concentration sensor 38 outputs a voltage having a value corresponding to the toner concentration.

The control unit includes information storage means such as RAM, in which Vref, which is a target value of the output voltage from the toner concentration sensor 38, is stored.
The control unit compares the output voltage value from the toner density sensor 38 with Vref, and supplies the toner amount according to the comparison result from a toner supply device (not shown) from the back side of the first developer storage unit 32 in the drawing. Replenish and maintain the toner concentration in the developer at the desired value.
Each time the replenished toner amount is replenished, the control unit records and accumulates it in an information storage means such as a RAM, and reads from the ID chip information that will be described later that the toner bottle described later is empty and replaced with a new toner bottle. The accumulated toner supply amount is reset.
This control by the toner density sensor 38 and the toner supply device is performed for each color individually.

As shown in FIG. 1, an exposure unit 44 as a latent image forming unit is disposed below each process unit in the drawing.
The exposure unit 44 irradiates the surface of the photosensitive drum of each process unit with the laser light L based on the image information. Thereby, an electrostatic latent image is formed on the photosensitive drum.
The exposure unit 44 has a configuration in which laser light emitted from a laser diode as a light source is scanned by a polygon mirror that is rotationally driven by a motor, and is irradiated onto a photosensitive drum through a plurality of optical lenses and mirrors.
An exposure unit using an LED array as a light source can also be adopted.

A first paper feed cassette 46 and a second paper feed cassette 48 are arranged below the exposure unit so as to overlap in the vertical direction.
Each of these paper feed cassettes accommodates recording paper (hereinafter also referred to as “transfer paper”) as a recording medium. The two paper feed rollers are in contact with each other.
When the paper feed roller is driven to rotate counterclockwise at a predetermined timing by a driving means (not shown), the recording paper is directed to a paper feed path arranged to extend vertically on the right side of the cassette in the drawing. Discharged.

A plurality of conveyance roller pairs are arranged in the paper feed path, and the recording paper sent to the paper feed path is conveyed upward by these conveyance roller pairs.
A registration roller pair 50 is disposed in the paper feed path. The recording paper conveyed through the paper feed path is temporarily stopped by the registration roller pair 50.
Then, the registration roller pair 50 is driven at a predetermined timing in accordance with the timing at which a toner image formed on an intermediate transfer belt described later reaches the secondary transfer nip, and feeds the recording paper toward the secondary transfer nip. .

A transfer unit 54 including an intermediate transfer belt 52 as an intermediate transfer member that rotates counterclockwise in the drawing is disposed above each process unit in the drawing.
In addition to the intermediate transfer belt 52, the transfer unit 54 includes a belt cleaning unit 56 and a primary transfer roller 58 disposed at a position where the photosensitive drums of the respective colors face each other.
Further, the transfer unit 54 includes a driving roller 60 that drives from the outside and drives the intermediate transfer belt, a driven roller 62, and a belt tension roller 64.
The drive roller 60 also serves as a counter roller for the secondary transfer roller 66.
The intermediate transfer belt 52 is rotationally moved in the counterclockwise direction in the figure by the rotational driving of the driving roller 60 while being supported by these rollers.

The primary transfer roller 58 is in contact with the photosensitive drum with the intermediate transfer belt 52 interposed therebetween to form a primary transfer nip.
The toner image on the photosensitive drum is transferred onto the intermediate transfer belt by applying to the primary transfer roller 58 a transfer bias having a polarity opposite to that of the toner image formed on the photosensitive drum.
The toner images of the respective colors formed by the process units of the respective colors are sequentially primary-transferred and superimposed on the intermediate transfer belt, and a color image is formed on the intermediate transfer belt.
A secondary transfer roller 66 serving as a transfer device and a secondary transfer unit is disposed outside the intermediate transfer belt at a position facing the driving roller 60 with the intermediate transfer belt 52 interposed therebetween.
The secondary transfer roller 66 comes into contact with the drive roller 60 with a predetermined load by a spring (not shown), thereby forming a secondary transfer nip.

The color image formed on the intermediate transfer belt is moved to the secondary transfer nip by the rotational movement of the intermediate transfer belt.
At the same time, the recording paper enters the secondary transfer nip from the registration roller pair 50 in synchronization with the entry of the toner image into the secondary transfer nip.
The toner image is secondarily transferred onto the recording sheet by a secondary transfer electric field and a nip pressure formed between the secondary transfer roller and the secondary transfer counter roller.
The electric field for secondary transfer is formed by applying a transfer bias having the same polarity as the toner to the secondary transfer counter roller and grounding the secondary transfer roller.

On the intermediate transfer belt after passing through the secondary transfer nip, a small amount of toner that has not been transferred to the recording paper remains and adheres.
This is cleaned by the belt cleaning unit 56. The belt cleaning unit 56 has a cleaning blade in contact with the surface of the intermediate transfer belt, and scrapes and removes the transfer residual toner on the belt.
The transfer residual toner removed from the intermediate transfer belt is stored in the waste toner bottle 68 and discarded.

A fixing device 70 is disposed above the secondary transfer nip.
The fixing device 70 includes a fixing roller 70a that includes an electromagnetic induction heat generating layer, a pressure roller 70b that contacts the fixing roller with a predetermined pressure to form a predetermined nip width, a temperature sensor (not shown), and the like.
On the left side of the fixing roller in the figure, there is an IH coil unit 72 that is an electromagnetic induction means for generating heat in the electromagnetic induction heating layer in the fixing roller.

The fixing roller is heated by electromagnetic induction by an IH coil. Each roller is rotated in a clockwise direction by a driving source (not shown), and the fixing roller is rotated in a counterclockwise direction.
The recording paper that has passed through the secondary transfer nip is separated from the intermediate transfer belt and then fed into the fixing device 70.
In the process of being conveyed from the lower side to the upper side in the drawing while being sandwiched between the fixing nips of the fixing device, the toner image is fixed on the recording paper by being heated by the fixing roller and simultaneously being pressurized by the fixing nip.
The recording paper subjected to the fixing process in this way is discharged out of the apparatus via a pair of paper discharge rollers and stacked on the upper surface of the printer main body.

Above the transfer unit 54, toner bottles 74 for each color that contain Y, C, M, and K toners are disposed.
Each color toner stored in a toner bottle 74 as a toner container is appropriately supplied to the developing device 10 of each color process unit.
These toner bottles 74 can be detached from the printer main body, and the toner bottle can be replaced when the toner remaining in the bottle runs out.
In FIG. 1, reference numeral 65 denotes an adhesion amount detection sensor that detects the adhesion amount of toner on the intermediate transfer belt 52.

As shown in FIG. 21, an ID chip 76 as a storage medium is integrally provided at the tip of the toner bottle 74.
The ID chip 76 includes information on the remaining amount of toner, toner type, lot number, destination, main unit contract form (annual toner use contract, bottle single unit sales contract), and information on the external additive state of the toner lot to be included ( Toner information) is stored.
The toner bottle 74 may have a bag shape as shown in FIG. 22 and the shape is not limited as long as the ID chip 76 can be provided.

When the toner bottle 74 is attached to the printer main body, the information of the ID chip 76 is stored in the information storage means such as the RAM described above.
Of the information stored in the ID chip 76, the information on the external additive state of the toner lot will be described in detail.
The information on the external additive in the present embodiment is the free amount of SiO ₂ . Although the measuring method is shown below, the information on the external additive state and the measuring method are not limited.
First, a method for measuring the amount of SiO ₂ per predetermined amount of toner will be described. 4 g of toner is pressed with a pressure molding machine at a pressure of 5 Mpa for 3 minutes to form a pellet.
The fluorescent X-ray of the toner in the pellet state is measured using a fluorescent X-ray analyzer, and the SiO ₂ content (measured as the silica content before application of ultrasonic energy) in the measured toner is obtained.

Next, a method for measuring the liberated amount of SiO ₂ will be described. First, 2.5 g of Neugen is weighed in a 500 ml beaker, 300 ml of distilled water is added and dissolved by sonication to obtain a dispersion solution.
Next, 4 g of toner is weighed and added to a 100 ml screw tube together with 50 ml of the above-mentioned dispersion solution, and ultrasonic energy is applied for 1 minute at an intensity of 30 W using an ultrasonic homogenizer.
Next, 50 ml of the ultrasonically applied toner dispersion solution is transferred to a centrifuge tube, and centrifuged for 3 minutes at 2500 rpm. After centrifugation, the supernatant of the centrifuge tube is discarded.

Further, the toner and the dispersion solution are separated by a suction filtration method using a funnel. Next, the separated toner is dried at 40 ° C. for 24 hours.
For the dried toner, the silica content after application of ultrasonic energy is obtained by the same method as that described above for measuring the silica content before application of ultrasonic energy.
The difference between the silica content before application of ultrasonic energy and the silica content after application of ultrasonic energy is defined as SiO ₂ liberation.

As shown in FIG. 1, the printer main body 2 is provided with a first fixing cooling fan 78, a second fixing cooling fan 80, and a cleaning means cooling fan 82.
In addition, a process unit cooling fan K, a process unit cooling fan M, a process unit cooling fan C, and a process unit cooling fan Y (not shown) are provided on the back side of the printer main body, and the corresponding unit is cooled according to control described later. doing.
The position and number of the fans are not limited, and there are other writing fans and exhaust fans, but they are omitted.

[Example 1]
The image forming apparatus is based on a Ricoh Image MPC4500.
The printing speed of this apparatus is 35 sheets / minute (A4Y), and the process speed is 205 mm / s. In addition, the Example shown below is one Embodiment of this invention, The timing of a process control and the control method are not limited.
The control unit as the image area ratio detection means calculates the area of the toner image to be developed per area of the image formation area from the image signal for each image forming operation, and averages the image area ratio for the latest 500 times. The value is recorded on a recording medium such as a RAM.

Further, the installation environment of the image forming apparatus is detected by the temperature / humidity sensor 4 described above. Based on the temperature / humidity information (environment information), the installation environment is determined in 9 stages as shown in FIG. ing.
Further, the number of image formations is counted, the total number of image formations is recorded on a recording medium such as a RAM, and the number of use of the replacement part including the drum cleaning blade is also recorded separately.
The count of the number of times of image formation is counted up as 1 count in the case of image formation on transfer paper of A4 size or smaller, and 2 count up in the case of image formation on transfer paper having a size larger than A4 size.
In addition, when the replacement part including the drum cleaning blade is replaced, the usage count of the part replaced by the service person is reset.
The usage amount of the drum cleaning blade is the usage amount of the cleaning device.

According to each information detected as described above, the values of α, β and γ are determined as shown in FIGS.
As shown in FIG. 4, α is an average image area ratio. As shown in FIG. 5, β is a temperature / humidity category, and specifically a value assigned according to the degree of the temperature / humidity category.
As shown in FIG. 6, γ is a drum cleaning blade usage amount, specifically a value corresponding to each range of blade usage counts.

Further, as shown in FIG. 7, the SiO ₂ liberation amount of the toner lot used is obtained from the ID chip of the toner bottle, the value of ε corresponding to this is determined, and the CPM down rate D is determined according to the following equation: decide. The control unit functions as toner information acquisition means.
CPM down rate D = α × β × γ × ε [%] Equation (1)
The CPM down rate D refers to the rate at which the number of prints per minute is defined as CPM and the CPM is reduced by extending the distance between sheets.
If 0 is assigned to equation (1), it means that CPM down is not performed.
The CPM in the default state of the image forming apparatus varies depending on the paper size and the like, but the inter-paper distance is extended so that the CPM is lowered by the CPM down rate D with respect to the CPM at each paper size.

An example is shown in FIG. FIG. 8 shows the inter-paper distance for each paper size and the CPM after CPM down when the CPM down rate D = 20%.
When the CPM down rate is 20%, the CPM after CPM down is 80% (100% -20%).
The conditions shown in FIGS. 4 to 6 are as follows. The inventors conducted continuous printing tests by changing the amount of free SiO _{2 in the} toner lot used, the image area ratio, the amount of drum cleaning blade used, the temperature and humidity, and the distance between papers. The numerical value is determined based on the result of whether or not streak-like white spots due to foreign matters adhering to the surface of the image carrier are generated.
In the continuous printing test, A4 My Paper (manufactured by NBS Ricoh Co., Ltd.) was used, and 200 sets of 1000 prints were performed with a printing operation of 5 pages as one set.

Conventionally, when an image having a high image area ratio is continuously printed in a high-temperature and high-humidity environment, the external additive component of the toner is fixed on the photosensitive drum when the usage amount of the drum cleaning blade exceeds 25000 counts. , Streaky white spots are generated on the image.
In this case, there is no countermeasure other than replacement of the photosensitive drum, and in order to prevent the occurrence of streak-like white spots, the upper limit of the usage amount of the drum cleaning blade is set to 25000 counts and replacement is supported.
On the other hand, the image forming apparatus of this embodiment can extend the life of the drum cleaning blade to three times that of the conventional one as shown in FIG. 9, thereby improving the usability by reducing the cost and reducing the frequency of parts replacement. Is able to.

As described above, in this embodiment, the image area ratio per predetermined image forming operation amount, the deterioration state (usage amount) of the cleaning device, and the plurality of conditions that may hinder the uniform application property of the lubricant The temperature / humidity and the external additive state information relating to the toner external additive adhesion to the image carrier are detected.
Then, the image formation interval at the time of continuous image formation is changed according to the information.
As a result, the transfer residual toner can be prevented from staying at the contact portion between the drum cleaning blade and the image carrier, and the transfer residual toner can be prevented from slipping through the cleaning device. Can be prevented.

[Example 2]
The uniform coating property of the lubricant is greatly related to the deterioration state of the lubricant coating device.
For example, in a lubricant application device that uniformly applies a lubricant to the surface by leveling with a lubricant application blade as described above, the amount of lubricant rubbed off by the lubricant application brush depends on the deterioration of the brush. It is greatly influenced.
Therefore, in this embodiment, the usage amount of the lubricant application device is also detected, and the image formation interval at the time of continuous image formation is changed according to the information.
An object of the present invention is to prevent the occurrence of abnormal images such as the above-mentioned streaky white spots more appropriately than the image forming apparatus of the first embodiment.

In this embodiment, for each image forming operation, the area of the toner image to be developed per image forming area is calculated from the image signal, and the average value of the latest image area ratios for 500 times is recorded in a recording medium such as a RAM. To record.
Further, the installation environment of the image forming apparatus is detected by the temperature and humidity sensor described above, and the installation environment is determined in 9 stages as shown in FIG. 3 based on the temperature and humidity information.
Furthermore, the number of image formations is counted, and the total number of image formations is recorded on a recording medium such as a RAM. The number of replacement parts including the drum cleaning blade and the lubricant application brush described above is also recorded separately. Yes.

The count of the number of times of image formation is counted up as 1 count in the case of image formation on transfer paper of A4 size or smaller, and 2 count up in the case of image formation on transfer paper having a size larger than A4 size.
When replacement parts including the drum cleaning blade and the lubricant application brush are replaced, the usage count of the parts replaced by the service person is reset.
According to each information detected as described above, the values of α, β, and γ are determined as shown in FIGS.
Further, as shown in FIG. 7, the SiO ₂ liberation amount of the toner lot used is obtained from the ID chip of the toner bottle, the value of ε corresponding to this is determined, and the CPM down rate D is expressed by the above equation (1). )
In addition, description about FIG. 8 demonstrated in Example 1 is abbreviate | omitted suitably.

4, 5, and 10, the inventors conducted a continuous printing test by changing the amount of SiO ₂ liberated in the toner lot used, the image area ratio, the amount of drum cleaning blade used, the temperature and humidity, and the distance between papers. This is a numerical value determined from the result of whether or not streak-like white spots due to foreign matters adhering to the surface of the image carrier are generated on the image.
In the continuous printing test, A4 My Paper (manufactured by NBS Ricoh Co., Ltd.) was used, and 200 sets of 1000 prints were performed with a printing operation of 5 pages as one set.
As can be seen from the values of γ shown in FIGS. 6 and 10, if the result of the continuous printing test shows that the deterioration of the drum cleaning blade has progressed but the deterioration of the lubricant application brush has not progressed much, the image bearing It can be seen that streak-like white spots caused by the foreign matter adhering to the body surface do not occur.
Therefore, the image forming apparatus of the present embodiment can reduce the CPM down rate by about 30% in the region where the usage amount of the lubricant application brush is 0 to 25000 counts, compared with the image forming apparatus of the first embodiment. is made of.

  In this embodiment, the amount of the lubricant application device used is also detected, and the image formation interval at the time of continuous image formation is changed in accordance with the information, so that the transfer residue more appropriately than the image forming device of Embodiment 1. It is possible to prevent the toner from slipping through the cleaning device.

[Example 3]
As a method for detecting the image area ratio, a method of detecting the area of a toner image to be developed per area of the image forming region from information read from a scanner or print information transmitted from the outside is generally used.
A technique for utilizing the image area ratio per image page as information is widely known.
As the image area ratio information in the present embodiment, the non-image area, that is, the inter-paper area, and the case where the image forming operation is temporarily stopped and the adjustment operation is performed are all included while the image carrier is rotating. The image area ratio per traveling area is detected.
That is, in this embodiment, the image area ratio per rotation time of the image carrier is detected, the image formation interval at the time of continuous image formation is changed according to the information, and the contact portion between the drum cleaning blade and the image carrier The purpose is to prevent the residual toner from remaining in the toner.

In this embodiment, during the rotation of the image carrier, the area of the toner image to be developed per continuous traveling area every 1000 msec is calculated from the image signal, and the average value of the latest image area ratio for 500 times is stored in the RAM or the like. Is recorded on the recording medium.
An image diagram of the image area ratio calculation is shown in FIG. Further, the installation environment of the image forming apparatus is detected by the temperature and humidity sensor described above, and the installation environment is determined in 9 stages as shown in FIG. 3 based on the temperature and humidity information.
Further, the number of image formations is counted, the total number of image formations is recorded on a recording medium such as a RAM, and the number of use of the replacement part including the drum cleaning blade is also recorded separately.
The count of the number of times of image formation is counted up as 1 count in the case of image formation on transfer paper of A4 size or smaller, and 2 count up in the case of image formation on transfer paper having a size larger than A4 size.

In addition, when the replacement part including the drum cleaning blade is replaced, the usage count of the part replaced by the service person is reset.
According to each information detected as described above, the values of α, β and γ are determined as shown in FIGS.
Further, as shown in FIG. 7, the SiO ₂ liberation amount of the toner lot used is obtained from the ID chip of the toner bottle, the value of ε corresponding to this is determined, and the CPM down rate D is expressed by the above equation (1). )
The conditions shown in FIGS. 4 to 6 are as follows. The inventors conducted continuous printing tests by changing the amount of free SiO _{2 in the} toner lot used, the image area ratio, the amount of drum cleaning blade used, the temperature and humidity, and the distance between papers. The numerical value is determined based on the result of whether or not streak-like white spots due to foreign matters adhering to the surface of the image carrier are generated.
In the continuous printing test, A4 My Paper (manufactured by NBS Ricoh Co., Ltd.) was used, and 200 sets of 1000 prints were performed with a printing operation of 5 pages as one set.

In the first embodiment, the effects of factors such as the presence / absence of the adjustment operation and the inter-paper distance that changes for each paper size cannot be reflected in the control.
In contrast, in the present embodiment, when there are many adjustment operations such as process control, or when the distance between sheets per sheet size is long, control is performed so that the value of α detected as image area ratio information becomes small. Yes.
For this reason, as shown in FIG. 12, the CPM down rate can be reduced compared to the first embodiment when there are many adjustment operations such as process control adjustment or when the distance between sheets per sheet size is long. .
In FIG. 12, the process control adjustment is executed every 50 pages, and the CPM down rate in the case where 10,000 pages of an image with an area ratio of 72% are printed using LE paper with A5 size paper is the same as that of the first embodiment. 3 is a result of comparison.

Further, in this embodiment, when the CPM is lowered by extending the distance between sheets, the image area ratio α that is automatically detected is detected to be small.
In the case where images having the same image area ratio continue, the CPM down mode is always continued in the first embodiment.
On the other hand, in this embodiment, the CPM down mode can be canceled as appropriate in accordance with the decrease in the amount of residual toner accumulated on the cleaning blade, and thus the CPM down rate can be appropriately reduced.

If the image area ratio per predetermined image forming operation amount is detected as the image area ratio per rotation time of the predetermined image carrier, it is compared with the case where the image area ratio per page of the image is detected. Thus, the image area ratio information can be more appropriately reflected in the control.
As a result, it is possible to prevent the transfer residual toner from slipping through the cleaning device more appropriately, and to prevent the occurrence of abnormal images such as streaky white spots.

[Example 4]
In this embodiment, for each image forming operation, the area of the toner image to be developed per image forming area is calculated from the image signal, and the average value of the latest image area ratios for 500 times is recorded in a recording medium such as a RAM. To record.
Further, the installation environment of the image forming apparatus is detected by the temperature and humidity sensor described above, and the installation environment is determined in 9 stages as shown in FIG. 3 based on the temperature and humidity information.
Further, the number of image formations is counted, the total number of image formations is recorded on a recording medium such as a RAM, and the number of use of the replacement part including the drum cleaning blade is also recorded separately.
The count of the number of times of image formation is counted up as 1 count in the case of image formation on transfer paper of A4 size or smaller, and 2 count up in the case of image formation on transfer paper having a size larger than A4 size.

In addition, when the replacement part including the drum cleaning blade is replaced, the usage count of the part replaced by the service person is reset.
Further, for the replacement part including the above-described lubricant application brush, the travel distance is calculated from the process linear velocity and the operation time, and recorded on a recording medium such as a RAM.
When the replacement part including the lubricant application brush is replaced, the travel distance record of the part replaced by the service person is reset.
According to each information detected as described above, the values of α, β and γ are determined as shown in FIGS.
Further, as shown in FIG. 7, the SiO ₂ liberation amount of the toner lot used is obtained from the ID chip of the toner bottle, the value of ε corresponding to this is determined, and the CPM down rate D is expressed by the above equation (1). )

4, 5, and 13, the present inventors performed continuous printing tests by changing the SiO ₂ liberation amount, image area ratio, drum cleaning blade usage amount, temperature / humidity, and inter-paper distance of the toner lot used, This is a numerical value determined from the result of whether or not streak-like white spots due to foreign matters adhering to the surface of the image carrier are generated on the image.
In the continuous printing test, A4 My Paper (manufactured by NBS Ricoh Co., Ltd.) was used, and 1000 continuous printings were performed.
As a result, in this embodiment, compared with the second embodiment, the deterioration state of the lubricant application brush is detected by the travel distance, so that the CPM down rate can be controlled more appropriately.
As shown in FIG. 15, the image formation count threshold value for shifting to CPM down becomes large, and control can be properly performed without causing unnecessary CPM down.
FIG. 15 shows the threshold for starting the CPM down when the continuous printing of 1000 prints is repeated using the above-mentioned A4 My Paper (manufactured by NBS Ricoh) while exchanging the drum cleaning blade at 10,000 counts. It is a representation.

The threshold value of the image forming apparatus of the present embodiment is about 1.8 times larger than that of the second embodiment.
This is because the travel distance varies depending on the number of image formations per set of continuous printing operations (hereinafter also referred to as “PPJ” or “P / J”).
In other words, this is the difference that is manifested by conducting the test of 1000 PPJ in Example 2 that was calculated by 5 PPJ. An example of the correlation between PPJ and travel distance is shown in FIG.

As a method for managing the deterioration state of a component, a method of counting how many pages of image forming operations have been performed after replacing a certain component is widely known.
However, the management of the number of pages is not appropriate because the deterioration state of the parts changes depending on the size of the transfer paper.
A method of double counting A3 size printing is also widely used. However, the deterioration state of parts also changes due to excessive non-image areas and adjustment operations other than image forming operations. Not appropriate.
Therefore, in the present embodiment, as described above, the deterioration state of the lubricant application brush is detected as the travel distance and reflected in the control, thereby more appropriately preventing the occurrence of abnormal images such as the aforementioned streaky white spots. It was decided.
Thereby, the occurrence of abnormal images such as streak-like white spots can be prevented more appropriately.

[Example 5]
In this embodiment, for each image forming operation, the area of the toner image to be developed per image forming area is calculated from the image signal, and the average value of the latest image area ratios for 500 times is recorded in a recording medium such as a RAM. To record.
Further, the installation environment of the image forming apparatus is detected by the temperature and humidity sensor described above, and the installation environment is determined in 9 stages as shown in FIG. 3 based on the temperature and humidity information.
Further, for the replacement parts including the drum cleaning blade and the lubricant application brush described above, the travel distance is calculated from the process linear velocity and the operation time, and is recorded on a recording medium such as a RAM.
In addition, when replacement parts including the drum cleaning blade and the lubricant application brush are replaced, the travel distance record of the parts replaced by the service person is reset.

According to each information detected as described above, the values of α, β, and γ are determined as shown in FIGS.
Further, as shown in FIG. 7, the SiO ₂ liberation amount of the toner lot used is obtained from the ID chip of the toner bottle, the value of ε corresponding to this is determined, and the CPM down rate D is expressed by the above equation (1). )
4, 5, and 16, the present inventors performed continuous printing tests by changing the SiO ₂ liberation amount, image area ratio, drum cleaning blade usage amount, temperature / humidity, and inter-paper distance of the toner lot used, This is a numerical value determined from the result of whether or not streak-like white spots due to foreign matters adhering to the surface of the image carrier are generated on the image.
The continuous printing test was repeated 1000 prints continuously using A4 My Paper (manufactured by NBS Ricoh).
As a result, in this embodiment, compared to the first embodiment, the deterioration state of the drum cleaning blade and the lubricant application brush is detected by the travel distance, so that the CPM down rate can be controlled more appropriately.

As shown in FIG. 17, the image formation count threshold value for shifting to CPM down becomes large, and it can be controlled appropriately without causing unnecessary CPM down.
FIG. 17 shows the threshold value for starting CPM down by image formation count when 1000 print continuous printing is repeated using the above-mentioned A4 My Paper (manufactured by NBS Ricoh).
The threshold value of the image forming apparatus of this embodiment is about 1.8 times larger than that of the first embodiment.
This is because the running distance varies depending on the number of image formations per set of continuous printing operations.
This is a difference which is manifested by conducting a test of 1000 PPJ in Example 2 which was calculated by 5 PPJ. An example of the correlation between PPJ and travel distance is shown in FIG.

  In this embodiment, since the deterioration state of the cleaning device is detected as the travel distance of the drum cleaning blade and reflected in the control, the occurrence of abnormal images such as streaky white spots can be prevented more appropriately.

[Example 6]
In this embodiment, for each image forming operation, the area of the toner image to be developed per image forming area is calculated from the image signal, and the average value of the latest image area ratios for 500 times is recorded in a recording medium such as a RAM. To record.
Further, the installation environment of the image forming apparatus is detected by the temperature and humidity sensor described above, and the installation environment is determined in 9 stages as shown in FIG. 3 based on the temperature and humidity information.
Further, the number of image formations is counted, the total number of image formations is recorded on a recording medium such as a RAM, and the number of use of the replacement part including the drum cleaning blade is also recorded separately.
The count of the number of times of image formation is counted up as 1 count in the case of image formation on transfer paper of A4 size or smaller, and 2 count up in the case of image formation on transfer paper having a size larger than A4 size.

In addition, when the replacement part including the drum cleaning blade is replaced, the usage count of the part replaced by the service person is reset.
According to each information detected as described above, the values of α, β and γ are determined as shown in FIGS.
Further, as shown in FIG. 7, the SiO ₂ liberation amount of the toner lot used is obtained from the ID chip of the toner bottle, the value of ε corresponding to this is determined, and the CPM down rate D is expressed by the above equation (1). )
When competing with CPM down for maintaining the fixing temperature appropriately, control is performed in accordance with the CPM with the larger CPM down rate.
CPM down to keep the fixing temperature properly is the control that lowers the CPM when the fixing temperature falls below a certain threshold because the fixing temperature decreases when paper or coated paper is continuously passed. is there.

A CPM down rate is set for each of a plurality of threshold values.
In Example 1, when the CPM down for maintaining the fixing temperature appropriately and the CPM down of the present invention compete with each other, the calculation was performed, and therefore a useless CPM down rate occurred.
On the other hand, in this embodiment, the CPM down rate can be lowered without causing a useless CPM down as shown in FIG.

As a method for changing the image forming operation interval, a method of extending the inter-paper distance is widely known. For example, in order to maintain an appropriate fixing temperature, a technique for detecting the fixing temperature and changing the inter-paper distance is used. It has been.
When the control for extending the image forming interval for the purpose different from that of the present invention and the image forming operation interval extending control of the present invention are performed at the same time, the inter-paper distance is doubled. As a result, the number of images formed per unit time is significantly reduced, resulting in waste.
Therefore, in this embodiment, as described above, when a plurality of controls for changing the image formation interval compete, the control with the longer image formation interval is prioritized to prevent the occurrence of unnecessary image formation interval extension. It was decided to.
Since priority is given to the control with the longer image formation interval, it is possible to prevent the occurrence of unnecessary extension of the image formation interval.

[Example 7]
In this embodiment, for each image forming operation, the area of the toner image to be developed per image forming area is calculated from the image signal, and the average value of the latest image area ratios for 500 times is recorded in a recording medium such as a RAM. To record.
Further, the installation environment of the image forming apparatus is detected by the temperature / humidity sensor 4 described above, and the installation environment is determined in 9 stages as shown in FIG. 3 based on the temperature / humidity information.
Further, the number of image formations is counted, the total number of image formations is recorded on a recording medium such as a RAM, and the number of use of the replacement part including the drum cleaning blade is also recorded separately.
The count of the number of times of image formation is counted up as 1 count in the case of image formation on transfer paper of A4 size or smaller, and 2 count up in the case of image formation on transfer paper having a size larger than A4 size.

In addition, when the replacement part including the drum cleaning blade is replaced, the usage count of the part replaced by the service person is reset.
In this embodiment, the target toner adhesion amount (δ) per unit area during solid image formation is changed according to the type of recording medium, and the target toner adhesion amount is one of the conditions for changing the image formation interval. It is said.

According to each information detected as described above, the values of α, β, γ, and δ are determined as shown in FIGS.
Further, as shown in FIG. 7, the SiO ₂ liberation amount of the toner lot used is obtained from the ID chip of the toner bottle, the value of ε corresponding to this is determined, and the CPM down rate D is determined according to the following equation: decide.
CPM down rate D = α × β × γ × δ × ε [%] Equation (2)
The CPM down rate D refers to the rate at which the number of prints per minute is defined as CPM and the CPM is reduced by extending the distance between sheets.
The CPM in the default state of the image forming apparatus varies depending on the paper size and the like, but the inter-paper distance is extended so that the CPM is lowered by the CPM down rate D with respect to the CPM at each paper size.

The conditions in FIGS. 4 to 6 and FIG. 19 are obtained by changing the SiO ₂ liberation amount, the image area ratio, the target toner adhesion amount, the drum cleaning blade usage amount, the temperature and humidity, and the distance between papers. This is a numerical value determined from a result of whether or not streak-like white spots due to foreign matters adhering to the surface of the image carrier are generated on the image by performing a continuous printing test.
The target toner adhesion amount per unit area at the time of solid image formation is changed according to the type of the recording medium.
In the continuous printing test, A4 My Paper (manufactured by NBS Ricoh Co., Ltd.) was used, and 200 sets of 1000 prints were performed with a printing operation of 5 pages as one set.

In the present embodiment, as described above, as a plurality of conditions that may hinder uniform application of the lubricant, the image area ratio per predetermined image forming operation amount, the target toner adhesion amount according to the paper type, The deterioration state of the cleaning device, the temperature and humidity, and the information on the external additive state relating to the adhesion of the external toner additive to the image carrier are detected.
Since the image formation interval at the time of continuous image formation is changed according to the information, it is possible to suppress the residual transfer toner from staying at the contact portion between the drum cleaning blade and the image carrier.
As a result, it is possible to prevent the transfer residual toner from slipping through the cleaning device, and it is possible to prevent the occurrence of abnormal images such as the aforementioned streaky white spots.

In the present embodiment, the target toner adhesion amount condition is taken into consideration in the first embodiment, but it may be taken into account in other embodiments.
In any case, an effect equal to or higher than that of the above embodiment can be obtained.

[Example 8]
In this embodiment, for each process unit (for each image forming unit) and for each image forming operation, the area of the toner image to be developed per area of the image forming area is calculated from the image signal, and the latest 500 times. The average image area ratio is recorded on a recording medium such as a RAM as Y (P), C (P), M (P), and K (P) for each process unit.
In a full-color image forming apparatus including process units such as black, cyan, magenta, and yellow, a toner image formed by an upstream process unit is reversely transferred to a downstream process unit carrier at a transfer unit. .
Since the toner of the upstream process unit is input to the cleaning unit of the downstream process unit, the image area ratio of the downstream process unit is not so high when the image area ratio of the upstream process unit is high. Since the amount of toner input to the cleaning blade is large, the cleaning performance cannot be exhibited sufficiently.

In this embodiment, in order to cope with this problem, the average image area ratio P is calculated for each process unit in consideration of the reverse transfer toner amount, as shown in FIG. The control value α shown in FIG.
This calculation method is an example, and the order of the process units and the calculation method are not limited.
Other condition values are set in the same manner as in the above embodiment. That is, the values of α, β, γ, etc. are determined for each process unit, and the CPM down rate D is determined according to Equation (1) or Equation (2).
Although the CPM down rate D is different for each process unit, the value with the highest CPM down rate D in each process unit is reflected as the control value. That is, the largest value among the image formation intervals calculated for each process unit is used.

If there is a process unit with a large amount of toner input to the cleaning blade in consideration of the image area ratio of all the process units, for example, an interval mode in which the image forming operation is temporarily stopped and the carrier is continuously rotated is executed.
In this way, the transfer residual toner staying at the contact portion between the cleaning blade and the carrier can be collected as waste toner.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to such specific embodiments, and unless specifically limited by the above description, the present invention described in the claims is not limited. Various modifications and changes are possible within the scope of the gist.
The effects described in the embodiments of the present invention are merely examples of the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

4 Temperature / Humidity Sensor as Environment Detection Sensor 6 Process Unit as Image Forming Means 10 Developing Device 12 Photosensitive Drum as Image Carrier 14 Drum Cleaning Device as Cleaning Device 14a Drum Cleaning Blade as Blade 16 Lubricant Application Device 22 Lubricant application brush as application brush 44 Exposure unit as latent image forming means 66 Secondary transfer roller as transfer device 74 Toner bottle as toner container

JP 2011-059320 A JP 2010-079019 A JP 2011-170320 A

Claims (9)

An image carrier;
Latent image forming means for forming an electrostatic latent image on the image carrier based on image information;
A developing device that attaches toner to the latent image on the image carrier to form a visible image;
A transfer device for transferring the visible image to a recording medium;
A cleaning device that removes toner remaining on the image carrier after the transfer with a blade in contact with the image carrier;
A lubricant application device for applying a lubricant on the image carrier;
An environment detection sensor for detecting the installation environment of the image forming apparatus;
A toner container containing toner to be replenished to the developing device;
In an image forming apparatus comprising:
An image area ratio detecting means for detecting an image area ratio of the visible image per predetermined image forming operation amount;
Continuous image formation according to the image area ratio detected by the image area ratio detection means, the usage amount of the cleaning device, the environmental information detected by the environment detection sensor, and the toner information in the toner container. An image forming apparatus characterized by changing an image forming interval at the time. The image forming apparatus according to claim 1.
The image forming apparatus, wherein the environmental information is temperature and humidity, and the toner information is information on an external additive state of toner stored in a storage medium integrally provided in the toner container. The image forming apparatus according to claim 1, wherein
An image forming apparatus characterized in that the amount of use of the lubricant application device is further added as a condition for changing the image forming interval. The image forming apparatus according to any one of claims 1 to 3,
An image forming apparatus characterized in that a target toner adhesion amount per unit area at the time of solid image formation is changed according to the type of recording medium, and the target toner adhesion amount is further added as a condition for changing an image forming interval. . The image forming apparatus according to any one of claims 1 to 4,
The image forming apparatus according to claim 1, wherein the predetermined image forming operation amount is a rotation time of the image carrier. The image forming apparatus according to claim 3.
The image forming apparatus, wherein the lubricant application device has a configuration in which a lubricant is applied to the image carrier by an application brush, and a usage amount of the lubricant application device is a travel distance of the application brush. . In the image forming apparatus according to any one of claims 1 to 6,
The image forming apparatus according to claim 1, wherein a usage amount of the cleaning device is a travel distance of the blade. The image forming apparatus according to any one of claims 1 to 7,
A structure for forming and transferring a visible image on the image carrier, a structure for cleaning toner remaining on the image carrier after the transfer, a structure for applying a lubricant on the image carrier, and the toner storage A plurality of image forming means having a configuration for replenishing toner from the body to the developing device, and calculating the image forming interval under conditions for each image forming means, and the largest of the calculated image forming intervals An image forming apparatus using a value. The image forming apparatus according to any one of claims 1 to 8,
An image forming apparatus characterized in that priority is given to a control with a longer image forming operation interval when a plurality of controls for changing the image forming interval compete.

Images