JP5338155B2 - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To clean a substance accumulated on a contact portion between an image holder and a board-like cleaning member, by a simple constitution without imposing an unnecessary load on the image holder. <P>SOLUTION: This device is equipped with: an image holder 1 which is rotatable in both directions, a board-like cleaning member 2 for cleaning residual toner on the image holder 1, and an accumulated substance cleaning means 3 for moving the substance P accumulated on the contact portion between the board-like cleaning member 2 and the image holder 1 from the portion and cleaning it. The accumulated substance cleaning means 3 has: an accumulated substance cleaning member 4 provided in contact with the image holder 1 only during the accumulated substance cleaning time for cleaning the accumulated substance P, for cleaning the accumulated substance P accumulated on the contact portion between the image holder 1 and the board-like cleaning member 2; an accumulated substance carrying-out means 5 for carrying out the accumulated substance P from the contact portion to a separated portion by reversely rotating the image holder 1 temporarily in the reverse direction which is different from a normal rotation direction; and a contact means 6 for bringing the accumulated substance cleaning member 4 into contact with the accumulated substance P at least during carrying out the accumulated substance P by the accumulated substance carrying-out means 5. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an image forming apparatus.

  For example, in an image forming apparatus adopting an electrophotographic system, an image forming apparatus that scrapes and cleans residual toner on a photosensitive member as an image holding member for holding a toner image with a rubber blade is known. In the method of cleaning the photosensitive member using such a blade, free external additives from the toner remain at the contact portion (nip region) between the photosensitive member and the blade, and gradually form a lump. Further, the cleaning performance of the photosensitive member is lowered, and the photosensitive member is easily damaged. For this reason, discharge products and the like deposited on the photosensitive member remain without being sufficiently cleaned, resulting in image quality deterioration such as dilation (image loss).

  The following methods are known as methods for cleaning residual toner and the like on the photoreceptor. Japanese Patent Application Laid-Open No. H10-228707 discloses a method in which the photoreceptor is repeatedly reversed / forward rotated so as to supply a uniform amount of lubricant to the blade edge for the purpose of preventing filming on the photoreceptor. Patent Document 2 discloses a method in which an upward blade is used and toner is supplied to a cleaning portion to ensure the cleaning performance of the blade. Further, in Patent Document 3, a conductive brush to which a voltage having the same polarity as the toner is applied is provided immediately above the upward blade, and a toner supply unit that returns the toner scraped off by the blade onto the photoreceptor again is configured. In this case, an effective toner reservoir is formed at the blade tip. Furthermore, in Patent Document 4, a cleaning brush and a cleaning blade are installed in this order with respect to the photoconductor along the rotation direction, and when cleaning the contact portion between the cleaning blade and the photoconductor, the tip of the cleaning blade is used. A cleaning device is disclosed in which the photosensitive member is reversely rotated so that the toner accumulation region reaches the upstream side of the cleaning brush once, and cleaning is performed by the cleaning brush, and then the photosensitive member is rotated forward.

JP 2007-101909 A (Best Mode for Carrying Out the Invention, FIG. 2) JP-A-2005-338615 (Example 1) JP 2006-276158 A (first embodiment, FIG. 3) Japanese Patent Laid-Open No. 7-84495 (Examples, FIGS. 3 to 5)

  The technical problem of the present invention lies in an aspect in which deposits on the image holding member are cleaned by a plate-like cleaning member, and it is easy for the stagnant matter remaining at the contact portion between the image holding member and the plate-like cleaning member. The object of the present invention is to maintain the cleaning effect of the plate-like cleaning member on the deposit on the image holding member and perform good image formation by cleaning the image holding member without applying an unnecessary load to the image holding member.

According to the first aspect of the present invention, an image holding body that holds a toner image and can freely rotate forward and backward is opposed to a normal rotation direction that is a rotation direction of the image holding body during normal toner image formation. A plate-shaped cleaning member for cleaning the residual toner on the image holding member, the tip-side surface of the image holding member being kept in contact with the image holding member and facing upward, and the plate-like cleaning member and the image holding member; The staying material cleaning means for moving and cleaning the staying material staying at the contact portion of the head and the image holding body is provided in the vicinity of the upper portion of the plate-like cleaning member, A film-like seal member that prevents toner from being cleaned and collects toner at a tip portion of the plate-like cleaning member, and the forward rotation direction of the image carrier is at a portion facing the plate-like cleaning member. In the direction from the top to the bottom. A staying material cleaning member for cleaning the staying material for cleaning the staying material, which is provided in contact with the image holding body only during cleaning of the staying material, and cleaning the staying material staying at the contact portion between the image holding body and the plate-like cleaning member, and A staying material carrying means for carrying out the staying material to a part separated from the contact part by temporarily reversing in a reverse direction different from the normal rotation direction, and the staying substance during the staying material unloading operation by at least the staying material unloading means. and a contact means for contacting the cleaning member and the retentate, the retentate cleaning member, and formed in contact on the image carrier in the forward direction upstream of the plate-like cleaning member from the image carrier An image holding member rotation that is composed of a cleaning toner image composed of a belt-like toner image that is in contact with the entire width of the plate-like cleaning member, and the staying material carrying-out means and the contact means rotate the image holding body in forward and reverse directions. This image consists of control means The holding body rotation control means rotates the image carrier in the normal rotation direction so that the cleaning toner image is brought into contact with the staying object before the staying object carrying-out operation, and then the cleaning toner image that has come into contact with the staying object. At the same time, the image carrier is rotated in the reverse direction so as to be carried out from the contact part. Further, the image carrier rotation control means is configured such that the cleaning toner image out of the staying matter and the cleaning toner image carried out from the contact part. Image retention is performed after the point of time when the plate-shaped cleaning member falls to the front end portion of the plate-shaped cleaning member and immediately after the cleaning toner image of the staying matter and the cleaning toner image carried out from the contact portion contacts the seal member. An image forming apparatus configured to rotate a body in a normal rotation direction.

The invention according to claim 2, in the image forming apparatus according to claim 1, wherein the image holding member rotation control means, the sealing member is cleaning the toner image of the unloading residence thereof and cleaning the toner image from the contact site The image forming apparatus controls the image holding member to repeat the reverse rotation operation and the normal rotation operation at a position in contact with.

Invention is an image forming apparatus according to claim 1 or 2, wherein the retentate cleaning means, history information of the image density of the normal toner image formed on the image carrier, usually toner formed according to claim 3 An image forming apparatus that operates based on at least one of image history information and environment information.

According to the invention which concerns on Claim 1, there can exist the following technical effects.
(1) The accumulated matter staying at the contact portion between the image carrier and the plate-like cleaning member can be cleaned with a simple structure and without applying an unnecessary load to the image carrier, and the deposit on the image carrier. The cleaning effect of the plate-like cleaning member is maintained, and good image formation can be performed over a long period of time.
(2) Compared to those not having this configuration, the cleaning toner can be supplied to the tip portion of the plate-like cleaning member in the state in which the accumulated matter is carried out, and an unnecessary load is applied to the image carrier. Therefore, it is possible to clean the accumulated matter with a simple configuration.
(3) Compared with the one not having this configuration, the staying matter staying at the contact portion between the image carrier and the plate-like cleaning member is once carried out from the portion together with the cleaning toner, and the cleaning toner image (specifically, Toner) falls to the tip portion of the plate-like cleaning member, so that it is possible to prevent the staying material from entering the contact portion when the image holding member rotates forward, and the staying matter adhering to the image holding member can be cleaned. It is made suitable.
(4) Compared to those not having this configuration, it is easier to form an effective toner reservoir at the tip portion of the plate-like cleaning member, and the cleaning toner accumulated in that portion is lifted as the image carrier is reversed. However, it can be dropped again by the seal member, and the cleaning effect of the image carrier can be improved.
According to the second aspect of the present invention, the cleaning toner can be surely dropped on the tip portion of the plate-like cleaning member as compared with the case without this configuration, and the cleaning effect of the image carrier is further improved. To improve.

According to the third aspect of the present invention, it is possible to maintain the cleaning performance for a long period of time without applying an unnecessary load to the image holding member by cleaning the accumulated matter when necessary. .

Outline of Embodiment Model First, an outline of an embodiment model to which the present invention is applied will be described.
FIG. 1 shows an outline of an image forming apparatus according to an embodiment model embodying the present invention. In the figure, the image forming apparatus according to the present embodiment model includes an image carrier 1 that holds a toner image and can freely rotate forward and backward, and a normal rotation that is the rotation direction of the image carrier during normal toner image formation. A plate-shaped cleaning member that is kept in contact with the image carrier 1 so as to face the direction and that has a tip end surface facing the image carrier 1 facing upward to clean residual toner on the image carrier 1 2, and the plate-like cleaning member 2 and the image carrier 1 retentate cleaning means 3 for cleaning by moving the retentate P which remained contact site from the site of the comprises, in the forward image carrier 1 The direction is a direction from top to bottom at a position facing the plate-like cleaning member 2, and the staying material cleaning means 3 is provided in contact with the image carrier 1 only during staying material cleaning for cleaning the staying material P. The stagnant material for cleaning the stagnant matter P remaining at the contact portion between the image carrier 1 and the plate-like cleaning member 2 The sweeping member 4, the staying material unloading means 5 for transporting the staying material P to a site separated from the contact site by temporarily reversing the image carrier 1 in the reverse direction different from the normal rotation direction, and at least the staying material transporting It has the contact means 6 which makes the stagnant cleaning member 4 and the stagnant P contact when the stagnant P is carried out by the means 5.

  Here, the image carrier 1 may be any one that can rotate forward and backward, and the shape may be a drum shape or a belt shape. Further, the plate-like cleaning member 2 may be any member that can clean the residual toner on the image carrier 1. In the present invention, the stagnant P remains at the contact portion between the plate-like cleaning member 2 and the image carrier 1. Therefore, a member using an elastically deformable rubber-based material is usually applied.

  Further, the stagnant cleaning means 3 may be any unit that removes the stagnant P remaining at the contact portion between the plate-like cleaning member 2 and the image carrier 1 and cleans it. Any function may be used as long as it functions when cleaning the staying matter P remaining at the contact portion with the image carrier 1. Therefore, the staying material cleaning member 4 is in contact with the image carrier 1 only at the time of staying material cleaning, and the timing at which the staying material cleaning member 4 by the contact means 6 contacts the staying material P is not particularly limited. It is sufficient that at least the staying material cleaning member 4 and the staying material P come into contact with each other during the unloading operation in which the staying material P is unloaded from the contact portion. There is no problem.

  Further, the staying material cleaning member 4 may be any member that can clean the staying material P directly or indirectly. Specifically, the staying material cleaning member 4 is charged with toner into a contact portion where the staying material P is carried out. Examples include a method for preventing the object P from entering the contact portion again, a method for cleaning the staying matter P carried out from the contact portion by using a dedicated cleaning member, and the method using toner includes an image carrier. For example, a method of forming a dedicated toner image on 1 and transporting it to a portion where the staying material P is present, or a method of directly supplying, for example, powder toner to the portion where the staying matter P is present.

And the following is mentioned as a 1st aspect which cleans the stay P stably. That is, as shown in FIG. 2A, the staying material cleaning member 4 is formed in contact with the image holding body 1 on the upstream side in the normal rotation direction of the image holding body 1 with respect to the plate-like cleaning member 2, and the plate-like cleaning member. 2 is constituted by a cleaning toner image TB formed of a belt-like toner image that is in contact with the entire width of the image, and the staying material unloading means 5 and the contact means 6 rotate the image holding body 1 in the forward and reverse directions. The image carrier rotation control means 7 is configured to rotate the image carrier 1 in the forward direction so that the cleaning toner image TB is brought into contact with the accumulated matter P before the accumulated matter carrying-out operation, and thereafter, The image holding body 1 may be rotated in the reverse direction so that the staying matter P is carried out from the contact portion together with the cleaning toner image TB that has come into contact therewith.

  Here, the cleaning toner image TB is formed on the image carrier 1 in order to supply new toner to the tip portion of the plate-like cleaning member 2, and first comes into contact with the image carrier 1. The position may be on the upstream side in the rotation direction of the image carrier 1 from the contact portion between the plate-like cleaning member 2 and the image carrier 1. Therefore, a dedicated image forming means may be arranged opposite to the image carrier 1 and the cleaning toner image TB may be formed using the image forming unit, or a normal toner image is formed on the image carrier 1. May be used to form the cleaning toner image TB, but the latter is preferred from the viewpoint of simplifying the apparatus configuration.

  Further, the cleaning toner image TB may be provided over a region corresponding to the plate-shaped cleaning member 2 in the width direction of the image carrier 1, or a region in which no image is formed on the image carrier 1 (non-image). The density of the cleaning toner image TB may be divided by these areas if there is an image forming area and an image forming area (image area), and a uniform toner over the entire width of the plate-like cleaning member 2 A toner image that can be supplied is preferable. The cleaning toner image TB is maintained as a toner image on the image holding member 1 until it comes into contact with the plate-like cleaning member 2, and after it comes into contact with the plate-like cleaning member 2, the image is held by the plate-like cleaning member 2. The toner 1 is scraped off from the body 1 to form a powdery toner (for example, a cluster). In this application, the toner supply in this state is the cleaning toner image TB. Call it.

  In this way, the cleaning toner image TB at the position A is brought into contact with the stay P by the image carrier rotation control means 7 (position B indicated by a broken line in the figure), and further, by the image carrier rotation control means 7. The staying matter P is removed from the contact portion by carrying out the staying matter P together with the cleaning toner image TB from the contact portion (position C indicated by a two-dot chain line in the figure). At this time, at the position C, a part of the cleaning toner image TB falls to the tip portion of the plate-like cleaning member 2 and covers the contact portion between the plate-like cleaning member 2 and the image carrier 1.

Further, when the cleaning toner image TB is used in this way, when cleaning the staying matter P adhering to the image carrier 1, from the viewpoint of peeling the staying matter P from the image carrier 1 and crushing it, the image holding The body rotation control means 7 further moves the image after the time when the cleaning toner image TB of the staying matter P carried out from the contact portion and the cleaning toner image TB falls to the tip portion of the plate-like cleaning member 2 has passed. It is necessary to rotate the holding body 1 in the forward rotation direction. According to this, since the dropped cleaning toner image TB is at the tip portion of the plate-like cleaning member 2, when the image carrier 1 is rotated forward, the contact portion between the image carrier 1 and the plate-like cleaning member 2 is not present. The cleaning toner image TB is first applied and the subsequent staying material P is prevented from entering. Therefore, even if the staying matter P tries to enter the contact site as the image carrier 1 rotates forward, it is shielded by the cleaning toner image TB, and the staying matter P is peeled off from the image carrier 1 and pulverized. Become distributed. The details of such an operation are left to the embodiment. Further, the forward rotation operation of the image carrier 1 may be performed at the time of cleaning the staying material, or may be performed at the next warm-up of the image forming apparatus, for example.

Furthermore, from the viewpoint of enhancing the cleaning effect of the staying material P in the method using the cleaning toner image, it is further provided in the vicinity of the upper portion of the plate-like cleaning member 2 so as to face the image holding member 1. A film-like seal member that prevents the toner cleaned by the cleaning member 2 from being scattered and collects toner at the front end portion of the plate-like cleaning member 2 is provided. Of the object P and the cleaning toner image TB, it is necessary to rotate the image carrier 1 in the forward rotation direction immediately after the cleaning toner image TB contacts the seal member. Here, the term “immediately after” is sufficient as long as the cleaning toner image TB is in contact with the seal member, and does not mean a timing at which the cleaning toner image TB exits the seal member. Absent.

  From the viewpoint of storing the cleaning toner image TB (corresponding to powdery toner) at the tip portion of the plate-like cleaning member 2 in the aspect including the seal member, the image carrier rotation control means 7 is provided with the contact portion. It is preferable to perform control so that the image holding body 1 repeats the reverse rotation operation and the normal rotation operation at a position where the cleaning toner image TB is in contact with the seal member out of the staying matter P and the cleaning toner image TB carried out from.

On the other hand, the following is mentioned as a 2nd aspect which cleans the stagnant P stably. That is, this is an embodiment that embodies the related invention related to the present invention . As shown in FIG. The image holding body 5 is configured by a brush member 8 that can come into contact with and separate from the image holding body 1 and is rotatable at the upstream side in the forward rotation direction, and the staying material carrying-out means 5 carries out the staying material P from the contact portion. 1 is constituted by an image carrier rotation control means 7 for performing reverse rotation control, and the contact means 6 is moved so that the brush member 8 can be brought into contact with and separated from the stay P during the carry-out operation by the image carrier rotation control means 7. The thing comprised by the brush member moving means 9 to be made is mentioned.

  Here, the brush member moving means 9 may be provided in a configuration different from the image holding body rotation control means 7 for controlling the rotation of the image holding body 1, but from the viewpoint of simplifying the apparatus configuration, the brush member moving means 9 may be provided. It is preferable that the member moving unit 9 moves the brush member 8 toward and away from the image carrier 1 in conjunction with the rotation of the image carrier 1 by the image carrier rotation control unit 7. Further, from the viewpoint of securing a stable contact / separation locus of the brush member 8 with respect to the image holding body 1, the brush member moving means 9 has a rotation axis of the brush member 8 when the brush member 8 contacts and separates from the image holding body 1. It is preferable to have a guide groove that is guided and moved. According to this, when the stagnant P is cleaned by the brush member 8, it is possible to prevent the brush member 8 from unnecessarily contacting the image holding body 1, and the cleaning effect of the stagnant P by the brush member 8 can be prevented. There is no loss.

  And in the aspect provided with the brush member 8, from the viewpoint of preventing unnecessary deterioration of the image carrier 1, the stay P on the image carrier 1 is transferred to the brush member 8 by the image carrier rotation control means 7 and the brush member moving means 9. It is preferable that the brush member moving means 9 separates the brush member 8 from the image carrier 1 after being cleaned in step (b). At this time, the timing at which the brush member 8 is separated from the image carrier 1 is not particularly limited, and may be separated along with the forward rotation operation of the image carrier 1 by the image carrier rotation control means 7. For example, they may be separated during the reverse rotation operation. However, when the brush member moving means 9 contacts and separates the brush member 8 in conjunction with the rotation operation of the image carrier 1, the brush member 8 holds the image in conjunction with the forward rotation operation of the image carrier 1. What is necessary is just to come away from the body 1. FIG.

  Further, from the viewpoint of maintaining the cleaning effect of the stagnant P by the stagnant cleaning means 3, the stagnant cleaning means 3 has the history information of the image density of the normal toner image formed on the image carrier 1 and the normal toner formed. It is preferable to perform an operation based on at least one of image history information and environment information. Here, the history information of the formed toner image is, for example, history information for grasping such a state because the amount of accumulated matter on the plate-like cleaning member 2 varies depending on the number of continuous prints or the number of prints. Point to.

Hereinafter, the present invention will be described in more detail based on embodiments shown in the accompanying drawings.
Embodiment 1
FIG. 3 shows an outline of the first embodiment of the image forming apparatus to which the above-described form model is applied. In the figure, the image forming apparatus according to the present embodiment includes an intermediate transfer belt 10 that is stretched in a substantially horizontal direction by a plurality of stretching rolls 11 to 14 and circulated and rotated, and the intermediate transfer belt 10 is stretched substantially linearly. Each color process cartridge 20 (20a to 20d) of four colors (for example, yellow, magenta, cyan, and black) is sequentially arranged along the one side of the bridge. Reference numeral 50 denotes a control device that performs various controls in the image forming apparatus.

  The intermediate transfer belt 10 is wound around a plurality of stretching rolls 11 to 14 and circulates and rotates using, for example, the stretching roll 11 as a driving roll, and temporarily holds and conveys a toner image. . A secondary transfer device 15 such as a secondary transfer roll is provided around the intermediate transfer belt 10 at a position facing the tension roll 14 and the intermediate transfer belt 10, and the tension roll 14 serves as a backup roll between the two. A secondary transfer electric field is applied to collectively transfer the toner image on the intermediate transfer belt 10 onto the recording material S supplied from a recording material supply unit (not shown). Further, a belt cleaning device 16 for cleaning toner remaining on the intermediate transfer belt 10 is provided at a position facing the stretching roll 11 with the intermediate transfer belt 10 interposed therebetween. The belt cleaning device 16 is provided so as to be retractable with respect to the intermediate transfer belt 10 and cleans residual toner, and agitation transport for transporting the toner cleaned by the blade 17 to a waste toner storage unit (not shown). A member 18 is provided.

  A primary transfer device 19 (such as a primary transfer roll) that transfers the toner image formed by the process cartridge 20 onto the intermediate transfer belt 10 is located at a position facing the process cartridge 20 on the back side of the intermediate transfer belt 10. 19a to 19d) are provided. Therefore, the respective color toner images transferred by the respective primary transfer devices 19 are multiplexed on the intermediate transfer belt 10, and the multiplexed toner images are collectively transferred onto the recording material S at the secondary transfer portion. Will come to be. A primary transfer electric field for transferring each color toner image onto the intermediate transfer belt 10 is applied between the primary transfer device 19 and the process cartridge 20, and the toner image is transferred at the secondary transfer portion. The recording material S transferred in a batch is fixed by a fixing device (not shown), for example, by the action of heating and pressing.

  FIG. 4 illustrates one process cartridge 20, and the process cartridge 20 of the present embodiment is configured to be detachable from the image forming apparatus housing. Since each process cartridge 20 (20a to 20d) has substantially the same configuration except for the developer to be used (in this example, a two-component developer including toner and carrier is used), only one process cartridge 20 will be described here. To do.

  The process cartridge 20 according to the present embodiment includes a photosensitive member 21 as an image holding member that holds a toner image and can be rotated forward and backward, a charging device 22 such as a charging roll that charges the photosensitive member 21, and charging by the charging device 22. The exposed photosensitive member 21 is exposed to form a latent image, and the latent image is developed with toner to form a visible toner image, and the toner image on the photosensitive member 21 is primarily transferred. And a cleaning device 40 that cleans residual toner on the photoreceptor 21 after being transferred onto the intermediate transfer belt 10 at the site. In addition, the arrow of the code | symbol 23 shows the laser beam irradiated corresponding to each color from a laser scanning apparatus as an exposure apparatus which is not illustrated, for example, In this Embodiment, one laser scanning apparatus is used, and each color is shown. The photosensitive member 21 of the process cartridge 20 is individually exposed through a gap (not shown) in the housing of each process cartridge 20.

  Further, the developing device 30 of the present embodiment includes a housing 31 having an opening at a position corresponding to the photosensitive member 21 side, and a developing roll 32 is disposed at a position facing the opening and facing the photosensitive member 21. Yes. The developing roll 32 has a magnet body in which magnetic poles N pole and S pole are appropriately arranged inside, and a nonmagnetic developing sleeve rotates around the magnet body. Around the developing roll 32, a regulating member 33 that regulates the layer thickness of the developer on the developing roll 32 is disposed with a predetermined gap with respect to the developing roll 32, and the rotation direction of the developing roll 32 from the regulating member 33. On the downstream side, a seal member 34 fixed to the housing 31 is provided to prevent the developer regulated by the regulation member 33 from scattering from the housing 31 to the outside. On the other hand, on the upstream side in the rotation direction of the developing roller 32 with respect to the regulating member 33, a supply agitating and conveying member 35 for supplying developer mainly to the developing roller 32 is disposed oppositely and obliquely below the developing roller 32. Behind the stirring and conveying member 35, there is provided a mixing and stirring and conveying member 36 that mainly performs frictional charging on the developer. The developer can be circulated between the supply stirring and conveying member 35 and the mixed stirring and conveying member 36 through the opening of the partition wall 31 a of the housing 31.

  In the developing device 30 having such a configuration, the developer stirred and conveyed by the two agitating and conveying members 35 and 36 is supplied onto the developing roll 32 by the supply agitating and conveying member 35. The developer supplied onto the developing roll 32 is transported to a developing region which is a portion facing the photoreceptor 21 in a state where a layer thickness is regulated by the regulating member 33 and a predetermined amount of developer layer is formed. In the developing region, the toner in the developer flies corresponding to the latent image on the photosensitive member 21 by the action of the developing electric field between the photosensitive member 21 and the developing roller 32, and the latent image on the photosensitive member 21 is visible. Imaged. Further, the developer beyond the developing region is collected on the supply stirring and conveying member 35 side by the action of a repulsive magnetic field due to the magnetic pole arrangement, for example, and conveyed to the mixed stirring and conveying member 36 side. In this embodiment, the developing device 30 uses a two-component developer. However, the developing device 30 is not limited to the two-component developer, and for example, a developing method using only toner may be used. Not too long.

  On the other hand, the cleaning device 40 includes a housing 41 having an opening facing the photoconductor 21 and a plate-like cleaning member provided corresponding to an opening edge on the lower side of the opening and cleaning residual toner on the photoconductor 21. As a blade 42, a film-like seal member 44 provided corresponding to the opening edge on the upper side of the opening and preventing scattering of the toner cleaned by the blade 42, and provided in the housing 41. And a stirring and conveying member 45 that conveys the waste toner collected therein to a waste toner storage unit (not shown). The base end side of the blade 42 opposite to the portion in contact with the photoreceptor 21 is attached to the housing 41 via a substantially L-shaped blade support member 43 and is the free end side of the blade 42. The front end surface on the opening side has a shape facing upward. In particular, in the present embodiment, the front end surface of the blade 42 is attached so that the contact portion side with the photoreceptor 21 is slightly lowered.

  Further, in the control device 50 (see FIG. 3) of the present embodiment, various types of image formation control and the like are performed. Here, a control system in the case of cleaning the accumulated matter on the photoreceptor 21 will be described. As shown in FIG. 5, the control device 50 of the present embodiment is configured so that the current environment is classified in advance from environmental information detected by an environmental sensor 51 (not shown in FIG. 3), For example, an environmental condition determination unit 52 is provided for determining whether a condition belongs to any one of a high temperature and high humidity condition, a low temperature and low humidity condition, and other conditions. Further, the control device 50 includes a history information storage unit 53 that stores history information on image formation. Here, the number of printed sheets, the image density, and the like are stored. In addition, the environmental condition determination unit 52 and the history information storage unit 53 have a staying material cleaning mode determination unit 54 that determines whether or not the staying material is to be cleaned. When it is determined that the staying material should be cleaned, the staying material cleaning mode is performed. In the control device 50, the staying material cleaning mode is performed by performing various drive controls of the charging device 22, the exposure device (indicated by 23 in this example), the developing device 30, and the rotation control of the photosensitive member 21. It is like that.

  A control flow (transition flow to the stagnant cleaning mode) in the control device 50 is as shown in FIG. First, determination is made by the environmental condition determination unit 52 based on information from the sensor 51 (S1). Next, the number of printed sheets that matches the determined environmental condition is selected from the table in the history information storage unit 53 (S2). Then, it is determined whether or not the actual number of printed sheets has reached the table value (S3). If the table value has not been reached, the process returns to S1, and if the table value has been reached, it is determined that the staying material needs to be cleaned. The stagnant cleaning mode is performed during non-image formation different from that during normal toner image formation (S4).

  In the stagnant cleaning mode in this embodiment, as shown in FIG. 7, first, a toner band as a cleaning toner image as a stagnant cleaning member is formed on the photosensitive member 21 (S11). At this time, toner bands having the same toner density may be formed along the rotation axis direction of the photoconductor 21, or the history information stored in the history information storage unit 53 (see FIG. 5). For example, along the rotational axis direction of the photosensitive member 21, the toner is classified into a portion where the toner is normally supplied and a portion where the toner is supplied when the toner image is formed, and the toner amount is supplied in a form corresponding to each portion. As described above, the toner density of the toner band may be changed over the rotation axis direction of the photoreceptor 21. Alternatively, the size of the toner band itself may be changed along the rotation axis direction of the photoreceptor 21.

  When the toner band is formed on the photoconductor 21, the toner band is moved in accordance with the rotation operation (forward rotation operation) of the photoconductor 21 to come into contact with the accumulated matter, and the leading position of the toner band is the tip of the blade 42. It is determined whether or not the predetermined position has been reached (S12). This is achieved by estimating the time during which the fresh toner in the toner band is reliably supplied to the tip portion of the blade 42 by the toner band. Next, when it is determined that the predetermined position has been reached, the photosensitive member 21 is switched from the normal rotation operation to the reverse rotation operation (S13), and reversely rotated for a predetermined time (S14). Thereafter, the photosensitive member 21 is switched again to the normal rotation operation (S15), and the staying material cleaning mode is ended when a predetermined time has elapsed (S16).

  Here, a staying thing is demonstrated. As shown in FIG. 8A, when cleaning of the residual toner on the photoreceptor 21 is continued with the blade 42, the external additive gradually released from the toner at the contact portion (nip area) between the blade 42 and the photoreceptor 21. Will remain, and a retained matter (toner lump containing a high concentration of external additive) P will be formed. The toner T further accumulates on the surface side of the staying matter P. This is because the external additive having a small diameter is easily released from the toner particles, and the edge of the blade 42 in the nip area is hidden under the rotation of the photosensitive member 21, and the nip area itself remains in the external additive. It also depends on the shape being easy. When the accumulated matter P stays in the nip area in this way, the cleaning effect of the photosensitive member 21 by the toner collected at the tip of the blade 42 is reduced, and good cleaning cannot be performed.

That is, if an effective toner reservoir cannot be formed at the tip of the blade 42 in this way, the fluidization of the toner here is hindered and the cleaning performance for the photoreceptor 21 is lowered. In particular, when the low-abrasive photoconductor 21 is used to extend the life of the photoconductor 21, for example, the discharge product adhered to the surface of the photoconductor 21 cannot be completely removed, and the moisture absorption of the discharge product is not achieved. Degradation of image quality (delation: so-called image omission) or the like may occur due to, for example.
Even if the photosensitive member 21 is reversed as shown in FIG. 8B in order to clean such staying matter P, the staying matter P is not exposed to the toner T adhering to the staying matter P. Since the adhesive force with the body 21 is strong, it moves together with the photoreceptor 21 as it is. Therefore, even if the photosensitive member 21 is rotated forward, the staying matter P returns to the nip region of the blade 42 as it is, so that the staying matter P is not removed.

Therefore, it is important to clean the staying material P remaining in such a nip region of the blade 42. Next, the cleaning action of the staying material P in the present embodiment will be described.
In this embodiment, as shown in FIG. 9A, a toner band TB is formed on the photoconductor 21 in the staying material cleaning mode, and this toner band TB is rotated by the rotation (forward rotation operation) of the photoconductor 21. By reaching 42 and being scraped off by the blade 42, the fresh toner T supplied by the toner band TB sequentially accumulates at the blade tip portion. Therefore, a large pool in which fresh toner T is sequentially accumulated is formed on the accumulated matter P in the nip area.

  Next, when the photosensitive member 21 is operated in reverse, the adhesion of the stay P (toner lump containing a high concentration of external additive) to the photosensitive member 21 is strong as shown in FIG. The toner T collected on 42 is lifted together with the staying matter P, and the staying matter P is carried out from the nip area. At this time, since the adhesive force between the fresh toners T is weak, when the toner T is lifted upward, a part of the toner T (portion surrounded by a dotted line in the figure) freely falls on the blade 42 and pours down sequentially. It becomes like this. Therefore, fresh toner T is accumulated on the blade 42 including the contact portion (corresponding to the nip area) between the blade 42 and the photosensitive member 21. When the photosensitive member 21 is rotated forward at such a stage, fresh toner T collected on the blade 42 enters the nip area first as shown in FIG. There is no room for P to enter, and the staying material P is peeled off from the photosensitive member 21 by the toner T newly supplied to the nip region, pulverized, and dispersed in the toner T at the tip portion of the blade 42. (In the figure, the symbol P ′ indicates a detained substance dispersed). As a result, the fluidity of the toner T at the tip portion of the blade 42 is maintained, and sufficient cleaning performance for the photoreceptor 21 is ensured.

  Furthermore, in the present embodiment, as shown in FIG. 9B ′, the toner T on the staying material P is obtained at the stage where the photosensitive member 21 is reversely moved by providing the seal member 44 above the blade 42. A large amount of the toner is dropped downward by the seal member 44, and a large amount of fresh toner T falls on the blade 42 at a stretch. Therefore, the cleaning action of the staying matter P appears more remarkably. At this time, the adhesion of the staying material P to the photoconductor 21 is strong. Therefore, even if the staying material P comes into contact with the seal member 44, it is difficult to separate the staying material P from the photoconductor 21 by the seal member 44. is there.

  In the present embodiment, the mode in which the timing for switching the photosensitive member 21 from the reverse rotation operation to the normal rotation operation is immediately shown. However, for example, a state where the reverse operation is performed and the fresh toner T is poured onto the tip portion of the blade 42. In this case, the photosensitive member 21 rotates (rotates in the forward direction) at the time of warm-up, for example. At this time, the blade 42 has already been rotated. Since the fresh toner T is present at the tip, the staying matter P adhering to the photoreceptor 21 is broken and dispersed by the fresh toner on the blade 42.

  Further, in order to supply the toner onto the blade 42 more effectively, the following modification may be adopted. That is, the photosensitive member 21 is rotated in the reverse direction, and after the fresh toner T is poured onto the tip portion of the blade 42 by the seal member 44, the photosensitive member 21 is caused to repeat the forward / reverse operation in the vicinity thereof. It may be. In this case, by increasing the frequency with which the toner T on the photosensitive member 21 contacts the seal member 44, it becomes possible to increase the amount of toner dropped to the tip portion of the blade 42, and the more stable stay P A cleaning action can be expected. Even if the sealing member 44 is repeatedly brought into contact, the staying matter P itself is hardly peeled off by the sealing member 44 because of its strong adhesion to the photoreceptor 21.

FIG. 10 shows one process cartridge 20 of the image forming apparatus according to the second embodiment to which the related invention related to the present invention is applied . Since the configuration of the image forming apparatus of the present embodiment is substantially the same as that of the first embodiment, description thereof is omitted here, and the process cartridge 20 will be described. Components similar to those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted here.

  In the figure, the process cartridge 20 of the present embodiment is configured in substantially the same manner as the process cartridge 20 of the first embodiment (see FIG. 4), but the cleaning device 40 is different from the first embodiment. Yes. In the present embodiment, a brush member 46 that contacts and separates from the photosensitive member 21 and rotates is provided in the housing 41 of the cleaning device 40 as a stagnant cleaning member.

In the present embodiment, the following brush member moving mechanism (corresponding to the brush member moving means as the contact means) is provided to bring the brush member 46 into and out of contact with the photosensitive member 21. FIGS. 11A and 11B show the brush member moving mechanism, where FIG. 11A is a view of the photosensitive member 21 as viewed from the circumferential surface direction, and FIG. 11B is a view of the photosensitive member 21 as viewed from the rotational axis direction. It is a figure.
In the present embodiment, a photoconductor gear 211 directly connected to the photoconductor 21 is provided on one end side of the photoconductor 21, and this photoconductor gear 211 is driven via a drive transmission system from a drive motor (not shown). The photoconductor gear 211 is rotated in the forward and reverse directions when the drive gear 212 is rotated in the forward and reverse directions by forward and reverse rotation of the drive motor. Further, the photoconductor gear 211 is provided with a drive transmission gear 213 having teeth meshing with the photoconductor gear 211.

  On the other hand, the brush member 46 is obtained by planting brush fibers 462 around the rotation shaft 461, and a brush gear 463 for rotating the brush member 46 is provided near one end of the rotation shaft 461 near the photoconductor gear 211. It has been. Between the brush gear 463 and the drive transmission gear 213, an intermediate gear 214 having teeth that mesh with each other is provided. Further, the brush member 46 of the present embodiment has a support plate 47 provided with a fan-shaped hole portion 471 (corresponding to a guide groove indicated by a two-dot chain line in the drawing) 471 in which the rotation shaft 461 is supported so as to be slidable. (Indicated by a two-dot chain line in the figure) is provided inside the brush gear 463, and the support plate 47 is supported by the housing 41 of the cleaning device 40, for example.

  Here, the operation of such a brush member moving mechanism will be described with reference to FIG. When the photoconductor gear 211 rotates in the direction of the arrow in the drawing (corresponding to the rotation control unit of the photoconductor 21 as the staying material carrying-out unit), the drive transmission gear 213 and the intermediate gear 214 rotate in the direction of the arrow, respectively. Then, the rotation of the intermediate gear 214 causes the brush gear 463 to rotate in the direction of the arrow, so that the rotation shaft 461 of the brush member 46 slides in the hole 471. As a result, the brush member 46 moves from the position A (position indicated by the broken line) to the position B while rotating. Even if the photoconductor gear 211 continues to perform the reverse rotation any more, the movement of the rotation shaft 461 of the brush member 46 is restricted by the hole 471, so that the brush member 46 is idled at this position. At this time, if the brush fibers 462 are brought into contact with the photoreceptor 21 before the brush gear 463 reaches the position B, stable cleaning with the brush fibers 462 can be performed. That is, the brush member 46 contacts the photoconductor 21 in the middle of the reverse rotation of the photoconductor 21, and the rotation direction at this time is such that the photoconductor 21 and the brush member 46 rotate in the same direction at the opposite portions. To come.

  On the other hand, when the photoconductor gear 211 is returned to the normal rotation operation, the brush gear 463 is returned from the position B to the position A, and even if the normal rotation operation is further performed, the brush gear 463 is idled at the position A. Become. By such a brush member moving mechanism, the brush member 46 can be brought into contact with the photosensitive member 21 in conjunction with the reverse rotation operation of the photosensitive member 21, and the brush is interlocked with the forward rotation operation of the photosensitive member 21. The member 46 can be separated from the photoconductor 21.

  In the present embodiment, since it is not necessary to form a toner band as in the first embodiment, the staying material cleaning mode in the control device 50 (see FIG. 3) has a flow as shown in FIG. . When it is determined by the control device 50 that the staying material needs to be removed, the staying material cleaning mode is performed at the time of non-image formation that is different from the image formation time for forming a normal toner image. In the stagnant cleaning mode, the photosensitive member 21 is reversed, and the brush member 46 comes into contact with the photosensitive member 21 (S21). Then, when a predetermined time has elapsed (S22), the photosensitive member 21 is rotated forward, and the brush member 46 is separated from the photosensitive member 21 (S23). And when predetermined time passes (S24), a stagnant cleaning mode will be complete | finished.

Next, the cleaning action of the staying thing in this Embodiment is demonstrated.
As shown in FIG. 13A, when the residual toner on the photoconductor 21 is cleaned by the blade 42, the staying matter P in which the external additive of the toner is accumulated at a high concentration remains in the nip region of the blade 42. Become. Therefore, fresh toner T newly scraped from the photoreceptor 21 is deposited on the staying material P.
When the photosensitive member 21 is operated in reverse in such a state, the staying matter P and the toner T are lifted upward as they are because the sticking force of the staying matter P to the photoreceptor 21 is strong. At this time, the brush member 46 moves so as to come into contact with the photosensitive member 21 in conjunction with the reverse rotation of the photosensitive member 21, so that when the stay P reaches a predetermined position as shown in FIG. The brush member 46 comes into contact with the photosensitive member 21, and the staying matter P is scraped off together with the toner T by the rotation of the brush member 46 and removed from the photosensitive member 21. A part of the scraped piece is left as it is. To fall into.

At this time, part of the accumulated matter P and toner T is wound upward by the brush member 46, but scattering from the cleaning device 40 to the outside is suppressed by the seal member 44 (see FIG. 10).
When the photosensitive member 21 is switched from the reverse rotation operation to the normal rotation operation at the stage where the residual matter P is cleaned by the brush member 46 as described above, the mixture of the residual matter P and the toner T dispersed in the nip region of the blade 42 is obtained. Therefore, for example, the external additive is not deposited at a high concentration, and the flow of toner at the tip portion of the blade 42 is kept good, so that the cleaning performance for the photosensitive member 21 is maintained. Become.

  In the present embodiment, the brush member 46 comes into contact with the photoconductor 21 in conjunction with the reverse rotation of the photoconductor 21, so that the brush member 46 contacts the surface of the photoconductor 21 unnecessarily for a long time. It is possible to suppress damage to the photoreceptor 21 without doing so.

Further, here, the photosensitive member 21 is rotated forward so that the brush member 46 is separated from the photosensitive member 21. However, the forward rotation operation is not necessarily performed in the staying material cleaning mode. After the stagnant P is cleaned in the mode, the apparatus is stopped in a state where the brush member 46 is in contact with the photosensitive member 21, and the brush member 46 is moved to the photosensitive member by the normal rotation operation of the photosensitive member 21 at the time of warming up at the next image formation. It may be separated from 21.
Further, as the brush member moving mechanism for moving the brush member 46, the mode interlocked with the rotation operation of the photosensitive member 21 has been shown. However, for example, a moving mechanism independent of the rotation of the photosensitive member 21 is provided for the brush member 46. But it doesn't matter.
In the present embodiment, the mode in which the blade 42 is arranged upward is shown. However, by using such a brush member 46, the blade 42 is applied in a direction different from the upward direction. Also good.

  In the first and second embodiments described above, the image forming apparatus for four colors is shown. However, the image forming apparatus is not limited to four colors, and the number thereof may be any number, and may be a single color. Five or more colors may be used. Further, for example, an embodiment in which one photoconductor is used and a plurality of developing devices are provided on the photoconductor may be used.

  Further, in the first and second embodiments described above, the method of determining the timing for performing the staying material cleaning mode from the history information such as the number of printed sheets under the environmental condition is shown. For example, the timing is determined only by the environmental condition and the history information. It can be determined. That is, for example, under low temperature and low humidity conditions in environmental conditions, when the blade 42 is applied to the photoconductor 21, wear of the photoconductor 21 becomes larger than in high temperature and high humidity conditions, and wear deterioration of the photoconductor 21 is likely to occur. That is, under low-temperature and low-humidity conditions, the staying material tends to form a stronger lump, and as a result, the photoreceptor 21 is easily worn by the staying material. For this reason, it is necessary to remove the accumulated matter at an early stage under such conditions. Therefore, you may make it determine the timing which performs the stagnant cleaning mode by discrimination | determination from environmental conditions. In addition, the timing for performing the staying material cleaning mode may be determined only from the history information.

Occurrence frequency of stagnant cleaning mode Fig. 14 (a) is an example showing the frequency of occurrence of stagnant cleaning mode in relation to the number of printed sheets, and describes the relationship between the number of continuously processed sheets and the frequency. It is. For example, under the condition that the number of continuously processed sheets is 3 or less (RL3 or less), the stagnant cleaning mode is performed once when such a print job is performed 1000 times. The frequency of performing the mode is increased, and the stagnant cleaning mode is implemented when the number of jobs is small.

  FIG. 14B is for weighting according to environmental conditions. In order to prevent the photoconductor from being worn under low temperature and low humidity conditions, the multiplier at low temperature and low humidity is set high. In addition, in the range of the tables 1-7, the environmental conditions are gradually changed from the low temperature and low humidity to the high temperature and high humidity in the high temperature and high humidity state. By using such a multiplier, it is possible to set conditions based on the influence of the accumulated matter on the environment by multiplying the number of continuous processing in FIG. 14A by the multiplier of (b).

Formation of Toner Band FIG. 15 shows an example of the exposure amount for forming a suitable toner band when, for example, the image density formed on the photoconductor is different with respect to the circumferential direction of the photoconductor. It is. For example, if the image formed on the photoconductor is divided into an image portion and a non-image portion along the rotation axis direction of the photoconductor, or the image density is significantly different, the toner By changing the exposure amount during band formation, the density of the toner band can be changed, and the amount of fresh toner supplied to the blade can be changed over the width direction of the image.

  In other words, since the portion with a large amount of residual toner tends to stay as a stay in the nip area, a toner band may be formed in accordance with the amount of the stay, and there are many places where there is a large amount of stay. In addition, a small amount of fresh toner is supplied to a portion where the amount of staying material remains, and the amount of good staying material is reduced while suppressing the amount of toner consumed as a toner band. Can be removed.

◎ Evaluation of accumulated matter on blade Here, it is an evaluation of what happens to a specific accumulated matter in the configuration of the first embodiment. Specifically, the environmental conditions were low temperature and low humidity conditions (for example, 10 ° C. and 30% RH), and the state of the blade surface after repeated printing was observed. The chart used for printing uses a mixture of a strip-shaped solid image (image portion) and a blank paper portion (non-image portion) continuous in the process direction (circumferential direction of the photoconductor), and 100 sheets of continuous processing (RL100) ), And the processing in the stagnant cleaning mode was performed, and then the continuous processing of 100 sheets was repeated, and such repetition was performed 20 times in total. The frequency of the staying material cleaning mode is set to once every 100 sheets from FIG. In FIG. 14B, the multiplier according to the environmental conditions was set to 1.0.
In addition, the toner band was formed with a band width of 20 mm, with reference to FIG. 15 and an exposure amount of 80% for the portion corresponding to the image portion and an exposure amount of 10% for the non-image portion.

The accumulated amount of accumulated matter is removed by removing the blade so as not to destroy the deposit at the tip of the blade, and blowing off the toner with air while observing the deposit adhering to the photoconductor with a microscope, so that the photoconductor is strong. The amount of stagnant material adhering to the image is photographed with a microscope (VK9500 manufactured by Keyence Co., Ltd.) that can simultaneously measure the height of the object, the external additive and the toner are identified by image processing, and the extracted external additive The quantity was measured as a volume.
Moreover, the thing which does not perform the stagnant cleaning mode was added as a comparative example.

The results, as shown in FIG. 16, in this embodiment, although the amount of deposition per 1μm width along the rotation axis direction of the photosensitive member becomes 101Myuemu ^3, in the comparative example was 155 .mu.m ^3, in this embodiment 2 It was confirmed that it decreased to about / 3. In addition, since the difference between the non-image area and the image area is smaller in the present embodiment than in the comparative example, it was confirmed that the staying material cleaning mode is effective. FIG. 17A shows the surface state with the blade removed in the above-described embodiment, and FIG. 17B shows the surface state with the toner removed by air.
Furthermore, the present inventor performed the same evaluation in the configuration of the second embodiment and was able to obtain the same result.

1 is an explanatory diagram showing an overview of an image forming apparatus according to an embodiment model embodying the present invention. The specific aspect of embodiment model is shown, (a) is a 1st aspect, (b) is explanatory drawing which shows a 2nd aspect. 1 is an explanatory diagram showing an overview of an image forming apparatus according to Embodiment 1. FIG. FIG. 3 is an explanatory diagram illustrating a process cartridge according to the first embodiment. FIG. 3 is a block diagram showing a control system of the first embodiment. It is a flowchart which shows the control flow in a control apparatus. It is a flowchart which shows the stagnant cleaning mode of a control flow. It is explanatory drawing which shows the effect | action of a normal staying thing, (a) shows a mode that the staying thing was formed, (b) shows a mode when a photoreceptor is reversed. (A)-(c) is explanatory drawing which shows the cleaning effect | action of the staying thing in Embodiment 1. FIG. FIG. 6 is an explanatory diagram showing a process cartridge according to a second embodiment. (A) (b) is explanatory drawing which shows the brush member moving mechanism of Embodiment 2. FIG. 6 is a flowchart illustrating a staying material cleaning mode according to a second embodiment. (A) (b) is explanatory drawing which shows the cleaning effect | action of the staying thing in Embodiment 2. FIG. It is a table | surface which shows an example with respect to the generation frequency of the stagnant cleaning mode in an Example, (a) shows the relationship between a continuous processing number of sheets and frequency, (b) shows an example of weighting of environmental conditions. 6 is a table showing an example of an exposure amount when forming a toner band. It is a table | surface and a graph which show the result of an Example. (A) (b) is explanatory drawing regarding the photograph which shows the state of the accumulated matter adhering to the photoreceptor surface in an Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image holding body, 2 ... Plate-shaped cleaning member, 3 ... Stagnant cleaning means, 4 ... Stagnant cleaning member, 5 ... Stagnant discharge means, 6 ... Contact means, 7 ... Image holding body rotation control means, 8 ... Brush member, 9... Brush member moving means, TB... Cleaning toner image, P.

Claims (3)

An image holding member that holds a toner image and is rotatable forward and backward;
Usually, the image holding member is kept in contact with the image holding member so as to face the normal rotation direction that is the rotation direction of the image holding member at the time of image formation, and the front end surface on the side in contact with the image holding member is arranged upward. A plate-like cleaning member for cleaning residual toner on the image carrier;
A stagnant cleaning means for moving the stagnant remaining at the contact portion between the plate-like cleaning member and the image carrier and cleaning the stagnant,
A film that is provided in the vicinity of the upper portion of the plate-like cleaning member so as to face the image holding member, prevents the toner cleaned by the plate-like cleaning member from being scattered, and collects toner at the tip portion of the plate-like cleaning member. A sealing member,
The forward rotation direction of the image carrier is a direction from the top to the bottom at a portion facing the plate-like cleaning member,
The stagnant cleaning means includes:
A stagnant cleaning member that is provided in contact with the image holding member only during the stagnant cleaning to clean the stagnant, and that cleans the stagnant remaining at the contact portion between the image holding member and the plate-like cleaning member;
A staying material unloading means for unloading the staying material to a site spaced from the contact site by temporarily reversing the image carrier in a reverse direction different from the normal rotation direction;
At least contact means for bringing the stay cleaning member and the stay in contact with each other during the unloading operation of the stay by the stay matter unloading means;
The stagnant cleaning member is formed of a belt-like toner image formed in contact with the image holding member on the upstream side in the forward rotation direction of the image holding member from the plate cleaning member and in contact with the entire width of the plate cleaning member. Consists of cleaning toner image,
The staying material carrying-out means and the contact means are constituted by image holding body rotation control means for rotating the image holding body in the forward and reverse directions,
This image carrier rotation control means rotates the image carrier in the normal rotation direction so that the cleaning toner image is brought into contact with the accumulated matter before the accumulated object carrying-out operation, and then the cleaning object that has contacted the accumulated material. Rotate the image carrier in the reverse direction so that it is carried out of the contact area together with the toner image,
Further, the image holding body rotation control means, after the time when the cleaning toner image of the accumulated matter and the cleaning toner image carried out from the contact portion falls on the tip portion of the plate-like cleaning member has passed, and An image forming apparatus characterized in that the image carrier is rotated in the normal rotation direction immediately after the cleaning toner image out of the accumulated matter and the cleaning toner image carried out from the contact portion contacts the seal member. . The image forming apparatus according to claim 1.
The image holding member rotation control means causes the image holding member to repeat the reverse rotation operation and the normal rotation operation at a position where the cleaning toner image comes out of contact with the seal member out of the staying material and the cleaning toner image carried out from the contact portion. An image forming apparatus that is controlled as described above. The image forming apparatus according to claim 1 or 2,
The stagnant cleaning unit operates based on at least one of information on history of density of a normal toner image formed on the image carrier, history information on the formed normal toner image, and environmental information. An image forming apparatus.