JP2006011221A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus equipped with a cleaning device having high cleaning performance and high durability, particularly, to provide an image forming apparatus in which high cleaning performance is retained even in use of toner with a small particle diameter. <P>SOLUTION: The image forming apparatus uses the cleaning device having a cleaning roller and a cleaning blade. For an image forming step, the apparatus sets a first condition in which a toner removal voltage for removing toner from an image carrier is applied to the cleaning roller and the cleaning blade is separated from the image carrier. For the cleaning performance recovery step, the apparatus sets a second condition in which a toner attachment voltage for attaching toner to the image carrier is applied to the cleaning roller and the cleaning blade is brought into contact with the image carrier. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, and a multifunction machine having these functions, and more particularly to an electrophotographic image forming apparatus.

  In an electrophotographic image forming apparatus, a cleaning blade made of a rubber blade is widely used as a cleaning unit for cleaning a photosensitive member, an intermediate transfer member, and the like after transferring a toner image.

  Rubber blades have a simple structure and have advantages such as excellent cleaning performance and are widely used, but for the purpose of obtaining higher cleaning performance and higher durability A cleaning device using a cleaning roller composed of a brush roller in combination with a cleaning blade has been studied.

For example, Patent Documents 1 and 2 disclose a cleaning device in which a cleaning blade is provided downstream of a cleaning roller composed of a brush roller to which a toner removal voltage is applied.
JP-A-7-219402 Japanese Patent Laid-Open No. 9-212057

  In recent years, there has been an increasing demand for higher image quality, and in order to meet this demand, there is a tendency to adopt an image forming technology using a small particle size toner. It has become possible to meet the needs for high image quality.

  However, in an image forming process using a toner having a small particle diameter, a cleaning device that cleans an image carrier after transfer requires higher performance than before. Further, from the viewpoint of improving the durability of the image forming apparatus, a cleaning apparatus that maintains high cleaning performance for a long period of time is required.

  When the cleaning blade and the cleaning roller are viewed from the viewpoint of cleaning performance and durability, there are the following problems that need to be solved.

  The cleaning blade scrapes and cleans the toner at the edge of the blade. However, due to wear of the edge, the load concentrated on the edge is reduced, and the cleaning performance is deteriorated.

  The cleaning roller performs cleaning by applying a voltage for attracting toner to the cleaning roller and electrostatically attracting the toner to the cleaning roller. As the toner accumulates on the cleaning roller, the electric resistance of the cleaning roller is increased. Increases, the electric field for attracting the toner decreases, and the cleaning performance decreases.

  Simply using a combination of a cleaning blade and a cleaning roller is not sufficient as a countermeasure against such deterioration of the cleaning performance of the cleaning blade and the cleaning roller.

  The present invention solves the above-described problems in a conventional cleaning device using a cleaning blade or a cleaning roller or a conventional cleaning device using a combination thereof, and a cleaning device that maintains a high cleaning performance for a long period of time. An object of the present invention is to provide an image forming apparatus.

The object of the previous period is achieved by any of the following inventions.
(Claim 1)
An image forming apparatus having an image carrier, a transfer device that transfers a toner image on the image carrier to a transfer member, and a cleaning device that cleans the image carrier after the transfer, wherein the cleaning device includes a cleaning roller, In an image forming apparatus having a cleaning blade,
A power source capable of applying a toner removal voltage or a toner adhesion voltage to the cleaning roller, a drive unit and a control unit for contacting and separating the cleaning blade from the image carrier,
The control unit controls the power source and the driving unit to apply the toner removal voltage to the cleaning roller, and to separate the cleaning blade from the image carrier, and to the cleaning roller. An image forming apparatus comprising: a second state in which the toner adhesion voltage is applied and the cleaning blade is in contact with the image carrier.
(Claim 2)
An image forming amount detecting unit configured to detect an image forming amount, wherein the control unit sets the first state until the image forming amount detected by the image forming amount detecting unit reaches a predetermined value; The image forming apparatus according to claim 1, wherein the second state is set when a formation amount reaches the predetermined value.
(Claim 3)
A dirt detecting device for detecting dirt on the cleaning roller, wherein the control means sets the first state until the dirt on the cleaning roller detected by the dirt detecting device reaches a predetermined value; The image forming apparatus according to claim 1, wherein the second state is set when contamination of the roller reaches the predetermined value.
(Claim 4)
The image forming apparatus according to claim 1, wherein the cleaning roller is a brush roller.
(Claim 5)
The image forming apparatus according to claim 1, further comprising a plurality of the cleaning rollers.
(Claim 6)
The image forming apparatus according to claim 1, wherein the control unit sets the first state during image formation and sets the second state during non-image formation.
(Claim 7)
The image forming apparatus according to claim 1, wherein the power source is a constant voltage power source.
(Claim 8)
The image forming apparatus according to claim 3, wherein the power source is a constant voltage power source, and the stain detection device detects the stain on the cleaning roller by detecting a current flowing through the cleaning roller.
(Claim 9)
The image forming apparatus according to claim 1, wherein the power source is a constant current power source.
(Claim 10)
The image forming apparatus according to claim 3, wherein the power source is a constant current power source, and the stain detection device detects the stain on the cleaning roller by detecting a voltage flowing through the cleaning roller.
(Claim 11)
A photosensitive member, a latent image forming device for forming an electrostatic latent image on the photosensitive member, and a developing device for developing the electrostatic latent image to form a toner image, wherein the image carrier is made of the photosensitive member. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.
(Claim 12)
A photosensitive member, a latent image forming device for forming an electrostatic latent image on the photosensitive member, a developing device for developing the electrostatic latent image to form a toner image, an intermediate transfer member, and a toner image on the photosensitive member; An image forming apparatus having a primary transfer device for transferring to an intermediate transfer member and a secondary transfer device for transferring a toner image on the intermediate transfer member to a recording material,
The image carrier is composed of at least one of the photosensitive member and the intermediate transfer member,
The image forming apparatus according to claim 1, wherein the transfer device includes at least one of the primary transfer device and the secondary transfer device.
(Claim 13)
The image forming apparatus according to claim 11, wherein the developing device performs development using a small particle size toner.

  According to any one of the first to thirteenth inventions, an image forming apparatus having a cleaning device having high durability and high cleaning performance and capable of forming a high-quality image is realized.

  According to the invention of claim 2 or claim 3, since the performance of the cleaning device is automatically improved, high-performance cleaning is always performed without placing a burden on the operator.

  According to the invention of claim 5, particularly high cleaning performance is maintained over a long period of time.

  According to the sixth aspect of the present invention, since the step of recovering the cleaning performance is performed during non-image formation, the cleaning performance can be recovered without affecting the image formation.

  According to the thirteenth aspect of the present invention, an image forming apparatus that stably forms an image with high image quality in terms of high resolution and excellent gradation expression is realized.

  FIG. 1 shows an image forming apparatus according to an embodiment of the present invention.

  As shown in the figure, a charging device 2, an exposure device 3, a developing device 4, a transfer device 5 and a cleaning device 6 are arranged around a photoreceptor 1 as an image carrier. The transfer device 5 is supplied with the recording material P from the paper supply unit 9, and the recording material P onto which the image has been transferred passes through the fixing device 8 and is fixed.

  As the photoreceptor 1, an OPC photoreceptor is preferably used, and a negatively chargeable OPC photoreceptor is particularly preferred. The exposure apparatus 3 is preferably an exposure apparatus that scans and exposes the photosensitive member 1 with a light beam, and a laser, an LED array, or the like is preferably used. The exposure device 3 forms a dot image on the photoreceptor 1 by exposure based on the image data. As the developing device 4, a developing device using a one-component developer containing toner as a main component without containing a carrier or a developing device using a two-component developer containing toner and a carrier is used, but a developing device using a two-component developer is used. A reversal developing type developing device that performs development with toner charged to the same polarity as the charged polarity of the photoreceptor 1 is particularly preferable.

  In order to form a high-resolution, high-quality image, a developing device using a small particle size toner is particularly preferable. The small particle size toner is a small particle size toner having a volume average particle size of 3 to 6 μm.

  A high-quality image having a high resolving power can be formed by such a small particle size toner. A toner having a volume average particle diameter larger than 6 μm weakens the characteristics of high image quality.

  When a toner having a volume average particle size of less than 3 μm is used, the image quality is likely to deteriorate due to fogging.

  The volume average particle diameter is a volume-based average particle diameter, and is a value measured by “Coulter Counter TA-II” or “Coulter Multisizer” (both manufactured by Coulter Co., Ltd.) equipped with a wet disperser. .

  For such a small particle size toner, a polymerized toner is preferable. The polymerized toner means a toner obtained by forming a binder resin for toner and forming the toner shape by polymerization of a raw material monomer or prepolymer of the binder resin and subsequent chemical treatment. More specifically, it means a toner obtained through a polymerization reaction such as suspension polymerization or emulsion polymerization and, if necessary, a step of fusing particles between them. In a polymerized toner, a raw material monomer or prepolymer is uniformly dispersed in an aqueous system and then polymerized to produce a toner, so that a toner having a uniform toner particle size distribution and shape can be obtained.

  Specifically, a polymer is produced by emulsion polymerization of a monomer in a liquid of an aqueous medium to which an emulsion is added or a suspension polymerization method, and then an organic solvent, agglomeration is produced. It can manufacture by the method of adding an agent etc. and making it associate. A method of preparing by mixing with a dispersion liquid of a release agent or a colorant necessary for the constitution of the toner at the time of association, or a toner component such as a release agent or a colorant dispersed in a monomer Examples thereof include emulsion polymerization. Here, the association means that a plurality of resin particles and colorant particles are fused.

  As the transfer device 5, a transfer device comprising a corona discharger or a transfer roller is preferably used.

  As the fixing device 8, a contact heating type fixing device that heats and pressurizes and fixes a toner image with a heating member and a pressure member is preferably used.

  A negative electrostatic latent image is formed on the photoconductor 1 by charging by the charging device 2 and exposure by the exposure device 3 in accordance with the rotation of the photoconductor 1 indicated by an arrow. The formed electrostatic latent image is developed by the developing device 4 to form a negatively charged toner image on the photoreceptor 1. The formed toner image is transferred to the recording material P by the transfer device 5.

  The transferred photoreceptor 1 is cleaned by a cleaning device 6.

  The recording material P supplied from the recording material storage unit 9 and to which the toner image has been transferred passes through the fixing device 8 and is subjected to body attachment processing.

  FIG. 2 shows the structure of the cleaning device 6.

  The cleaning device 6 includes a cleaning roller 61 and a cleaning blade 62, a power source 63, a flicker 64, and a scraper 65.

  The cleaning roller 61 is a conductive roller, and a brush roller is preferable.

The cleaning roller 61 preferably has a resistance of 10 ² Ω to 10 ¹⁵ Ω, and a brush roller made of conductive fibers such as nylon, acrylic, or polyester that has been made conductive is preferably used.

  As shown in the figure, the cleaning roller 61 rotates in contact with the photoreceptor 1 to remove toner and paper dust on the photoreceptor 1. The rotation direction may be either the same direction as the photoconductor 1 or the reverse direction. The cleaning blade 62 is made of a rubber blade such as urethane rubber, and scrapes off toner and paper dust on the photosensitive member 1 with an edge that contacts the photosensitive member 1. The leaning blade 62 is driven by a solenoid 66 as driving means to take a solid line and a dotted line position. The flicker 65 is made of a conductive columnar or cylindrical member such as metal and rotates in contact with the cleaning roller 61 to remove toner, paper dust, and the like from the cleaning roller 61. A voltage is applied to the cleaning roller 61 by a power source 63 via a flicker 64. The power source 63 includes a power source 63A that applies a voltage having a polarity opposite to that of the toner and a power source 63B that applies a voltage having the same polarity as that of the toner. The power sources 63A and 63B are switched and used.

  The toner cleaned by the cleaning device 6 has a charge charged in the developing device 4, and is cleaned in an image forming apparatus that uses a negatively charged photoreceptor and performs development by the developing device 4 that performs reversal development. The toner is negatively charged. Accordingly, the power source 63 </ b> A applies a positive toner removal voltage to the flicker 64 to remove the toner from the photoreceptor 1. Further, the power source 63B applies a negative toner adhesion voltage to the flicker 64 to cause the toner to adhere to the photoreceptor 1 from the cleaning roller 61.

  FIG. 3 shows a control system for performing control related to cleaning in the image forming apparatus shown in FIG.

  In the present invention, in the image forming process, a cleaning performance recovery process is performed in which the image carrier is cleaned by the cleaning roller, and the toner is removed from the cleaning roller when the toner is accumulated on the cleaning roller.

  In the example of FIG. 3A, a cleaning performance recovery process is performed in which the toner is removed from the cleaning roller when the image formation amount reaches a predetermined value.

  The control means CR sets the cleaning device 6 to the first state in the image forming process for forming an image on the recording material P.

  In the first state, the controller CR applies a toner removal voltage for removing toner from the photoreceptor 1 to the cleaning roller 61, that is, applies a positive voltage from the power source 63 </ b> A to the flicker 64 and the cleaning roller 61. In the first state, the control means CR sets the cleaning blade 62 at a position away from the photoreceptor 1 as indicated by a solid line.

  Therefore, in the first state, the transfer residual toner on the photoconductor 1 is attracted to the cleaning roller 61 by a positive toner removal voltage, removed from the photoconductor 1, and the photoconductor 1 is cleaned by the cleaning roller 61.

  The control means CR sets the cleaning device 6 to the second state when the count value of the number counter PC for counting the number of image formations used as the image formation amount detection means for detecting the image formation amount reaches a predetermined value. .

  In the second state, the control means CR applies a toner adhesion voltage for transferring toner from the cleaning roller 61 to the photoreceptor 1 to the cleaning roller 61 by switching the power source from 63A to 63B. In the second state, the control means CR also operates the solenoid 66 as the driving means to move the cleaning blade 62 to the position of the dotted line, that is, the position in contact with the photoreceptor 1.

  Due to the toner adhesion voltage, the toner accumulated on the cleaning roller 61 moves to the photoreceptor 1 and adheres to the photoreceptor 1. The toner adhering to the photoreceptor 1 is removed by the cleaning blade 62.

  In the image forming process, since cleaning is performed using the cleaning roller 61, the cleaning blade 61 is prevented from being deteriorated, and the deterioration of the cleaning performance of the cleaning roller 61 is set to the second state and the photosensitive member 1 and the cleaning roller are cleaned. By rotating the roller 61, the toner accumulated in the cleaning roller 61 is removed and the cleaning performance is recovered, so that high cleaning performance is maintained.

The means for detecting the image formation amount is not limited to the number counter for counting the number of image formations. For example, a detection means for detecting the image formation amount by integrating the amount of image data can be used.
In the example shown in FIG. 3B, the control means CR detects a resistance value of the cleaning roller 61, thereby detecting a resistance value of the cleaning roller 61. The resistance value detected by the resistance sensor RS as a dirt detection device is a predetermined value. Is reached, the cleaning device 6 is set to the second state, and the toner is removed from the cleaning roller 61.

  As shown in FIG. 4, the resistance sensor RS includes an electrode E that contacts the cleaning roller 61 and a voltmeter F that detects the voltage of the electrode E. As described above, the cleaning roller 61 is made of conductive fibers, but the resistance value of the entire roller brush increases as the toner accumulates. Therefore, by measuring the resistance value of the cleaning roller 61, it is possible to detect the degree of contamination of the cleaning roller 61, in other words, a decrease in the cleaning performance of the cleaning roller 61. When the resistance value of the cleaning roller 61 reaches a predetermined value, the control means CR sets the cleaning device 6 to the second state and performs a cleaning performance recovery process for removing the toner from the cleaning roller. As the resistance sensor RS, an ammeter can be used instead of the voltmeter F. When a constant voltage power source is used as the power source 63, an ammeter is used as the resistance sensor. When a constant current power source is used as the power source 63, a voltmeter is used as the resistance sensor RS.

The control means CR executes the cleaning performance recovery process as follows. Then, some of the following execution modes can be combined and executed.
(1) When the image forming process is executed, the cleaning performance recovery process is executed as a pre-process. (2) The cleaning performance recovery process is executed as a post-processing at the end of the image forming process. (3) (4) Execute the cleaning performance recovery process when the image forming apparatus starts up immediately after the power is turned on. FIG. 5 shows the color image forming apparatus according to the embodiment of the present invention. FIG.

  This color image forming apparatus is called a tandem type color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an intermediate transfer unit 7, and a paper feeding and conveying device and a fixing device 24. Become. A document image reading device SC is disposed above the color image forming apparatus.

  The image forming unit 10Y that forms a yellow image includes a charging device 2Y, an exposure device 3Y, a developing device 4Y, a primary transfer device 5Y, and a cleaning device 6Y disposed around the photoreceptor 1Y. The image forming unit 10M that forms a magenta image includes a photoreceptor 1M, a charging device 2M, an exposure device 3M, a developing device 4M, a primary transfer device 5M, and a cleaning device 6M. The image forming unit 10C that forms a cyan image includes a photoreceptor 1C, a charging device 2C, an exposure device 3C, a developing device 4C, a primary transfer device 5C, and a cleaning device 6C. The image forming unit 10K that forms a black image includes a photoreceptor 1K, a charging device 2K, an exposure device 3K, a developing device 4K, a primary transfer device 5K, and a cleaning device 6K.

  The intermediate transfer unit 7 includes a semiconductive endless belt-shaped intermediate transfer body 70 that is supported by a plurality of rollers 71 to 74 and circulates.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred and superimposed on the circulating intermediate transfer body 70 by the primary transfer devices 5Y, 5M, 5C, and 5K, and the combined color. An image is formed. The recording material P accommodated in the paper feeding cassette 20 is fed by the paper feeding device 21 and is conveyed to the secondary transfer device 5A through a plurality of intermediate rollers 22A, 22B, 22C, 22D and a registration roller 23. A color image is collectively transferred onto the recording material P. The recording material P onto which the color image has been transferred is fixed by the fixing device 24, conveyed to the paper discharge roller 25, and discharged onto a paper discharge tray 26 outside the apparatus.

  On the other hand, after the color image is transferred to the recording material P by the secondary transfer device 5A, the intermediate transfer member 70 passes through the cleaning device 6A, and the residual toner is removed.

  During the image forming process, the primary transfer device 5K is always in pressure contact with the photoreceptor 1K. The other primary transfer devices 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  FIG. 6 shows the structure of the cleaning device 6A.

  The cleaning device 6 </ b> A includes a cleaning roller 61 including a brush roller, a cleaning blade 62, a power source 63, a flicker 64, a scraper 65, a solenoid 66, and a conveying screw 67.

  The intermediate transfer member 70 as an image carrier is supported by rollers 71 and 75 that are grounded at a position facing the cleaning device 6A.

  As described with reference to FIG. 3, in the image forming process, the controller CR applies a toner removal voltage from the power source 63A to the flicker 64 and the cleaning roller 61, and the cleaning blade 62 from the intermediate transfer member 70 as indicated by a solid line. Then, the cleaning device 6A is set to the first state, and in the cleaning performance recovery process, the toner adhesion voltage is applied from the power source 63B to the flicker 64 and the cleaning roller 61, and the intermediate transfer member 70 is indicated by the dotted line of the cleaning blade 62. The cleaning device 6A is set to the second state apart from the above.

  Also in the example shown in FIG. 6, an embodiment in which the cleaning device 6 is controlled based on the number of formed images and an embodiment in which the cleaning device 6 is controlled based on the resistance value of the cleaning roller are possible.

  FIG. 7 shows the structure of another example of the cleaning device. In the example of FIG. 7, the intermediate transfer member 70 is cleaned using two cleaning rollers 611 and 612. A toner removal voltage or a toner adhesion voltage is applied to the cleaning roller 611 by a power source 631A or 631B, and a toner removal voltage or a toner adhesion voltage is applied to the cleaning roller 612 by a power source 632A or 632B, and flickers 641 and 642 are applied. Touch. Further, scrapers 651 and 652 are in contact with the flickers 641 and 642, respectively.

  The cleaning performance recovery process may be performed together on the cleaning roller 611 and the cleaning roller 612, or the cleaning performance recovery process is performed independently on the cleaning roller 611 and the cleaning roller 612. It is also possible.

  In the embodiment shown in FIGS. 6 and 7, the cleaning device according to the present invention is used as the cleaning device 6A for the intermediate transfer member 7 as the image carrier, but the photosensitive members 1Y, 1M, The cleaning device according to the present invention can also be used for the 1C and 1K cleaning devices 6Y, 6M, 6C, and 6K.

  Using the color image forming apparatus shown in FIG. 5, the image forming process and the cleaning performance recovery process were performed with the intermediate transfer body 70 and the cleaning apparatus 6 </ b> A having the configurations and conditions shown in Table 1.

  In Example 1, a test is performed in which the image forming process is restarted after the toner is removed from the cleaning roller by switching from the image forming process (first state) to the cleaning performance recovery process (second state) when forming 5000 images. went.

  In Example 2, monitoring was performed to measure the resistance value of the cleaning roller, and when the resistance value increased, the cleaning performance recovery process was performed. Specifically, the cleaning performance recovery step was performed when a constant voltage was applied to the cleaning roller and the current flowing through the brush roller was reduced to 2 μA. The initial current value when the cleaning roller is free of toner contamination was 10 to 15 μA.

  Images with a printing rate of 4% were continuously formed on A4 size paper, and 100,000 images were formed. For every 25000 sheets, five continuous images (one color) were formed, and the cleaning performance was evaluated. The evaluation is a visual evaluation of image contamination due to poor cleaning in an image formed on a recording material.

  The contents of Examples 1 and 2 and the comparative example are as follows.

Example 1: Cleaning performance recovery process is performed every 5000 sheets. Example 2: Cleaning performance recovery process is performed when the current value of the resistance sensor becomes 2 μA or less. Comparative Example 1: Cleaning is performed only with a cleaning blade without using a cleaning roller. Comparative Example 2: Using only the cleaning roller, cleaning without using the cleaning blade, and applying a voltage of +500 V to the cleaning roller Table 2 shows the experimental results.

  As shown in Table 2, in Examples 1 and 2, good cleaning performance was maintained, but in Comparative Example 1, cleaning failure occurred on 100,000 sheets and in Comparative Example 2 on 25,000 sheets.

1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the structure of a cleaning apparatus. 2 illustrates a control system that performs control related to cleaning in the image forming apparatus illustrated in FIG. 1. It is a figure which shows a resistance sensor. 1 is a diagram illustrating a color image forming apparatus according to an embodiment of the present invention. It is a figure which shows the structure of a cleaning apparatus. It is a figure which shows the structure of the other example of a cleaning apparatus.

Explanation of symbols

6, 6A, 6Y, 6M, 6C, 6K Cleaning device 61, 611, 612 Cleaning roller 62 Cleaning blade 63, 631, 63A, 63B, 631A, 631B Power supply 66 Solenoid CR control means,
PC number counter RS resistance sensor

Claims (13)

An image forming apparatus having an image carrier, a transfer device that transfers a toner image on the image carrier to a transfer member, and a cleaning device that cleans the image carrier after the transfer, wherein the cleaning device includes a cleaning roller, In an image forming apparatus having a cleaning blade,
A power source capable of applying a toner removal voltage or a toner adhesion voltage to the cleaning roller, a drive unit and a control unit for contacting and separating the cleaning blade from the image carrier,
The control unit controls the power source and the driving unit to apply the toner removal voltage to the cleaning roller, and to separate the cleaning blade from the image carrier, and to the cleaning roller. An image forming apparatus comprising: a second state in which the toner adhesion voltage is applied and the cleaning blade is in contact with the image carrier. An image forming amount detecting unit configured to detect an image forming amount, wherein the control unit sets the first state until the image forming amount detected by the image forming amount detecting unit reaches a predetermined value; The image forming apparatus according to claim 1, wherein the second state is set when a formation amount reaches the predetermined value. A dirt detecting device for detecting dirt on the cleaning roller, wherein the control means sets the first state until the dirt on the cleaning roller detected by the dirt detecting device reaches a predetermined value; The image forming apparatus according to claim 1, wherein the second state is set when contamination of the roller reaches the predetermined value. The image forming apparatus according to claim 1, wherein the cleaning roller is a brush roller. The image forming apparatus according to claim 1, further comprising a plurality of the cleaning rollers. The image forming apparatus according to claim 1, wherein the control unit sets the first state during image formation and sets the second state during non-image formation. The image forming apparatus according to claim 1, wherein the power source is a constant voltage power source. The image forming apparatus according to claim 3, wherein the power source is a constant voltage power source, and the stain detection device detects the stain on the cleaning roller by detecting a current flowing through the cleaning roller. The image forming apparatus according to claim 1, wherein the power source is a constant current power source. The image forming apparatus according to claim 3, wherein the power source is a constant current power source, and the stain detection device detects the stain on the cleaning roller by detecting a voltage flowing through the cleaning roller. A photosensitive member, a latent image forming device for forming an electrostatic latent image on the photosensitive member, and a developing device for developing the electrostatic latent image to form a toner image, wherein the image carrier is made of the photosensitive member. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. A photosensitive member, a latent image forming device for forming an electrostatic latent image on the photosensitive member, a developing device for developing the electrostatic latent image to form a toner image, an intermediate transfer member, and a toner image on the photosensitive member; An image forming apparatus having a primary transfer device for transferring to an intermediate transfer member and a secondary transfer device for transferring a toner image on the intermediate transfer member to a recording material,
The image carrier is composed of at least one of the photosensitive member and the intermediate transfer member,
The image forming apparatus according to claim 1, wherein the transfer device includes at least one of the primary transfer device and the secondary transfer device. The image forming apparatus according to claim 11, wherein the developing device performs development using a small particle size toner.

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