JP2005300916A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus with which the blade of a blade cleaning device, detachable by a user, is prevented from curling and image defects caused by a cleaning blade are also prevented. <P>SOLUTION: The image forming apparatus includes an image carrier for forming a toner image on it, and a plate-like cleaning member abutting on the image carrier, thereby cleaning the surface of the image carrier, the plate-like cleaning member being freely brought into contact with the image carrier and separated from it. In the image forming apparatus, at the start of the rotation of the image carrier, the image carrier is reversely rotated only by a prescribed amount and then rotated in a normal direction, in the case of which the rotating direction of the image carrier for a period of image formation is defined as the normal direction. In addition, when the image carrier is reversely rotated by the prescribed amount at the start of its rotation, the rotating speed of the image carrier is gradually increased. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer that employs an electrophotographic system or an electrostatic recording system.

  Conventionally, as an image forming apparatus, an electrophotographic image forming apparatus that transfers a toner image on the surface of an image carrier to a transfer material and obtains an image on the transfer material, or a toner image on the surface of the first image carrier is secondly used. The image is once transferred to the surface of the image carrier (hereinafter referred to as primary transfer), and then the toner image on the surface of the second image carrier is transferred again to the transfer material (hereinafter referred to as secondary transfer). An image forming apparatus is known. Then, as a cleaning means for removing the toner adhering to the first and second image carrier surfaces, the edge portion is brought into pressure contact with the first or second image carrier surface to scrape and remove the adhering toner. There is a cleaning blade system including a plate-like cleaning member made of an elastic material such as urethane rubber.

  In the cleaning blade method, when the life of the cleaning blade and the intermediate transfer unit holding the second image carrier is short enough to maintain the original performance, the life of the cleaning blade and the second image carrier is affected. However, there has been proposed a cleaning device that can be replaced at the end of each life and can be easily detached from the intermediate transfer unit (Patent Document 1).

  As a method of fixing the cleaner unit to the intermediate transfer unit, this cleaning device is fixed to the positioning boss on the intermediate transfer unit side with a latch on the cleaner unit side, and a separation arm that rotates in conjunction with the movement of the latch is disposed. When the cleaner unit is set, the cleaning blade is retracted and set by the separation arm interlocked with the movement of the latch, and then comes into contact with the intermediate transfer belt surface from substantially the orthogonal direction. In addition, the cleaning blade can be retracted by moving the latch to be separated.

JP 2002-132057 A

  However, in the cleaning blade method, when the cleaning blade is arranged in the counter direction with respect to the normal movement direction of the image carrier, the following problems may occur. For example, when the image forming apparatus is used continuously for a long time, the cleaning blade hardness decreases due to the heat generated by the image forming apparatus itself, and the image carrier is caught (turned up) at the time of start-up, and good cleaning performance cannot be maintained. The rotation of the image carrier is stopped by the increase in torque of the image carrier due to turning of the cleaning blade, and the toner is fused on the image carrier by the heat generated at this time.

  In addition, when the image carrier is started again when the image forming apparatus is not used for a long time, the toner adhered to the tip of the cleaning blade without being scraped off when left for a long time is transferred to the intermediate transfer member. There is a problem that an image becomes defective by slipping through the cleaning blade at startup.

  In addition to the above, in the removable cleaning device, the positioning accuracy between the cleaning device and the image forming apparatus tends to be deteriorated. FIG. 2 is a schematic diagram of a blade cleaning method, and will be described using this.

  In the normal blade cleaning device, the cleaning blade 91 and the image carrier 90 arranged in the counter direction with respect to the normal movement direction h of the image carrier are in a tangential direction at a contact position z of the image carrier and a predetermined direction. Abut at a certain angle.

  However, in a removable cleaning device, it is difficult to make contact with a uniform contact angle in the width direction for each attachment, and the cleaning blade is in an oblique direction z2 with respect to the original contact position z1 with respect to the image carrier. Since it abuts against z2 and the abutment angle of the cleaning blade differs in the width direction, the blade may be turned over or sufficient cleaning performance may not be obtained. For this reason, blade turning or image defects may occur more frequently than in the fixed cleaning blade method.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus capable of preventing image failure due to blade turning and cleaning blades in a blade cleaning apparatus removable by a user. It is to provide.

  In order to achieve the above object, an image carrier having a toner image formed thereon, and a plate-like cleaning member that contacts the image carrier and cleans the surface thereof, the plate-like cleaning member having the image carrier. In an image forming apparatus capable of freely contacting and separating from a body, when the rotation direction at the time of image formation of the image carrier is set to a positive direction, the image carrier at the time of starting the rotation of the image carrier Is rotated in the reverse direction by a predetermined amount and then rotated in the forward direction.

  According to a second aspect of the present invention, in the first aspect of the invention, when the image carrier is rotated in the reverse direction by a predetermined amount when the image carrier starts to rotate, the rotational speed of the image carrier is gradually increased. It is characterized by increasing.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, only when the image carrier is started immediately after the plate-like cleaning member comes into contact with the plate carrier from a state separated from the image carrier, the image is formed. The carrier is rotated in the reverse direction by a predetermined amount in the reverse direction, and then rotated in the forward direction.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, the first image carrier on which the toner image is formed, and the first image carrier on which the toner image is transferred from the first image carrier. The image carrier that has two image carriers and is capable of freely contacting and separating the plate-like cleaning member is the second image carrier.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the first image carrier is separated from the second image carrier during the reverse rotation operation at the time of startup of the second image carrier. Features.

  According to a sixth aspect of the present invention, in the fourth aspect of the invention, the first image carrier is reversed by the same amount as the second image carrier when the second image carrier is rotated reversely at startup. It is characterized by rotating in the direction.

  According to the present invention, it is possible to provide an image forming apparatus capable of preventing image failure due to blade turning and a cleaning blade in a blade cleaning apparatus removable by a user.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
This embodiment is an example using an intermediate transfer type color image forming apparatus. When the intermediate transfer belt is started, an intermediate transfer that corrects the attitude of the removable belt cleaning device to an ideal state and obtains good cleaning. The belt control will be described.

  FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus of the present invention. The color image forming apparatus according to the present embodiment will be described below with reference to the drawings.

  The image forming apparatus is constituted by four photosensitive drums and an intermediate transfer type full-color printer. The image forming apparatus includes four color image forming units (image forming stations 10) 10Y, 10M, 10C, and 10K of yellow (Y), magenta (M), cyan (C), and black (K), and further intermediate The image forming apparatus includes a transfer device including an intermediate transfer belt 80 as a transfer member, a belt cleaner 30 that collects waste toner that is not transferred to the transfer material P and remains on the intermediate transfer belt 80, and a fixing device 40.

  Each of the image forming stations 10Y, 10M, 10C, and 10K is configured as an image forming unit, and photosensitive drums (drum-shaped electrophotographic photosensitive members) 70Y, 70M, 70C, and 70 as first image carriers are respectively provided in the direction of arrow a. It is installed in a rotatable manner. On the outer peripheral surface of the photosensitive drum, primary charging rollers 12Y, 12M, 12C, and 12K that uniformly charge the surface of each photosensitive drum are disposed, and correspond to image signals on the downstream side in the rotational direction of the photosensitive drum. The laser exposure devices 13Y, 13M, 13C, and 13K that expose the modulated laser beam on the surface of the photosensitive drum are further arranged on the downstream side, and electrostatic latent images of the respective colors on the surface of the photosensitive drum formed by laser exposure. Are provided with developing units 14Y, 14M, 14C, and 14K that use yellow, magenta, cyan, and black toners of corresponding colors.

  Primary transfer rollers 54Y, 54M, 54C, and 54K that form a primary transfer portion together with the photosensitive drum are opposed to each other at a position (transfer position) between the photosensitive drums 70Y, 70M, 70C, and 70K. ing. Primary transfer power supplies 48Y, 48M, 48C, and 48K are connected to the primary transfer rollers 54Y, 54M, 54C, and 54K as primary transfer power supplies, and variable primary transfer voltages Vy, Vm, Vc, and Vk are applied to the primary transfer rollers 54Y, 54M, 54C, and 54K, respectively. .

  The intermediate transfer belt 80 as a second image carrier is installed on three rollers of a driving roller 52, a tension roller 51, and a secondary transfer counter roller 53, and vertically passes through the image forming stations 10Y to 10K. The photosensitive drums 70Y to 70K are arranged in contact with each other. The intermediate transfer belt 80 is rotationally driven by the driving roller 52 in the direction of the arrow b in the figure. Drum cleaners 16Y, 16M, 16C, and 16K are installed downstream of the primary transfer rollers 54Y, 54M, 54C, and 54K of the photosensitive drums 70Y, 70M, 70C, and 70K.

  A secondary transfer belt cleaner 30 is disposed at a position facing the tension roller 51 of the intermediate transfer belt 80. The belt cleaner 30 includes a cleaning blade 301 disposed in the rotation direction b and the counter direction during image formation of the intermediate transfer belt 80, a pressure spring 302 that presses the cleaning blade 301 against the intermediate transfer belt 80, and a cleaner that holds them. A cleaner apparatus including a container 305. Specifically, there is a cleaning blade 301 in which urethane rubber is formed in a plate shape on a blade support sheet metal 309, and a shaft 303 held by a cleaner container 305 is used as a center to press the intermediate transfer belt 80 at a predetermined angle by a pressure spring 302. It is in pressure contact.

  A tension roller 51 is positioned on the opposite portion of the cleaning blade 301 to serve as a backup roller, and the cleaning blade 301 comes into contact with the intermediate transfer belt 80 with a predetermined linear pressure. The toner scraped off by the cleaning blade 301 is temporarily collected in the cleaner container 305 as waste toner, sent by a screw 304 installed at the bottom of the cleaner container 305, and not shown separately installed in the apparatus main body. In the waste toner box. Further, a squeeze sheet 306 that contacts the intermediate transfer belt 80 is installed upstream of the position of the cleaning blade 301 of the cleaner container 305 in order to prevent the toner scraped off by the cleaning blade 301 from scattering inside the apparatus main body. ing.

  Here, as a characteristic configuration in the present embodiment, the belt cleaner 30 is configured to be detachable from the intermediate transfer unit 81 because its lifetime does not match the lifetime of the intermediate transfer belt 80.

  Next, a removable mechanism will be described with reference to FIG. 3 (a dotted line portion represents a member inside the cleaner container 305) in which the front cross section of the belt cleaner 30 in FIG. 1 is enlarged.

  A boss 802 for positioning the belt cleaner 30 is disposed on the bearing member 801 of the tension roller 51. The boss 802 is integrally formed with the tension roller bearing member 801, and a similar boss 802 (not shown) is also provided at the same position on the back side of the symmetrical intermediate transfer unit 81 with the tension roller 51 interposed therebetween.

  Further, the belt cleaner 30 is also located at the same position on the back side with the latch 308 and the cleaner container 305 interlocked with a lever (not shown) used when the user brings the belt cleaner 30 into contact with the intermediate transfer unit 81. A similar latch 305 (not shown) is provided. These latches 308 and 308 are arranged so as to fit into the cleaner positioning bosses 802 and 802 when they are brought into contact with the intermediate transfer unit 81. The following operations are performed to make contact and separation from the separated state.

  The belt cleaner 30 is inserted into the intermediate transfer unit 81 from the front of the image forming apparatus in a direction orthogonal to the paper conveyance direction (perpendicular to the paper surface) and hits a butting portion (not shown) located behind the intermediate transfer unit 81. Push in. As a result, the back screw drive input portion (not shown) of the belt cleaner 30 is fitted into a round slot (not shown), and the waste toner conveying screw 304 is pivoted when the belt cleaner 30 contacts and separates. It becomes. Therefore, the belt cleaner 30 is moved to the intermediate transfer unit 81 by rotating the screw 304 as the center of rotation in the direction of the arrow x in FIG. 3 and pushing it up until the latches 308 and 308 are hooked on the bosses 802 and 802. Set and come into contact. Further, in order to change from the contact state to the separation state, the screw 304 as the rotation center is rotated in the direction of the arrow y in FIG. 3 to release the latches 308 and 308 from the bosses 802 and 802. The belt cleaner 30 is separated from the intermediate transfer unit 81.

  The image forming operation of the image forming apparatus configured as described above will be described using the yellow image forming station 10Y as an example with reference to FIG.

  The surface of the photosensitive drum 70Y of the yellow station 10Y is negatively charged uniformly by the primary charging roller 12Y in the process of rotating in the direction of arrow a, and then image exposure is performed by the laser exposure unit 13Y. An electrostatic latent image corresponding to the yellow image component of the document is formed on the surface. This latent image is developed using negatively charged yellow toner by the developing device 14Y, and the latent image is visualized as a yellow toner image. The obtained yellow toner image is primarily transferred onto the intermediate transfer belt 80 by applying a primary transfer voltage from the primary transfer power supply 48Y to the primary transfer roller 54Y. After the transfer, the transfer residual toner adhering to the surface of the photosensitive drum 70Y is removed by the drum cleaner 16Y and used for the next image formation.

  The above-described image forming operation is performed at a predetermined timing in each of the image forming stations 10Y to 10K, and the toner images on the photosensitive drums 70Y to 70K are sequentially superimposed on the intermediate transfer belt 80 at the respective primary transfer portions to be primary. Transcript. In the full color mode, the toner images are sequentially transferred to the intermediate transfer belt 80 in the order of yellow, magenta, cyan, and black. In the single color or 2-3 color mode, the toner images of the necessary colors are as described above. Transcribed in the same order.

  Thereafter, the four-color toner images on the intermediate transfer belt 80 are transferred to the secondary transfer counter roller with the secondary transfer roller 55 grounded with the intermediate transfer belt 80 interposed therebetween as the intermediate transfer belt 80 rotates in the direction of arrow b. The secondary transfer voltage from the secondary transfer power supply 49 to the secondary transfer roller 55 is transferred onto the transfer material P which is moved to the secondary transfer portion in contact with the roller 53 and supplied thereto at a predetermined timing by the feeding roller 20. The secondary transfer is performed collectively by applying.

  The transfer material P on which the four-color toner images are secondarily transferred is conveyed to the fixing device 40, where it is pressurized and heated, and the four-color toners are melted and mixed to be fixed on the transfer material P. A full-color image is formed on the transfer material P. On the other hand, the transfer residual toner remaining on the surface of the intermediate transfer belt 80 that has finished the secondary transfer is removed by the belt cleaner 30.

  The above is the image forming operation of the image forming apparatus in the present embodiment.

  Next, regarding the reverse rotation operation when the intermediate transfer member of the present image forming apparatus is activated, FIG. 4 is an enlarged view of one longitudinal section of the belt cleaner 30 in FIG. 1 and FIG. 5 is a control timing chart of the reverse rotation operation. I will explain.

  In FIG. 5, it is assumed that the horizontal axis is the time axis, the upward direction of the vertical axis is rotated in the moving direction during image formation (hereinafter referred to as the forward direction), and the downward direction is rotated in the opposite direction. And As shown in FIG. 4, when the edge 301 a at one end of the cleaning blade is in contact with the intermediate transfer belt 80 at a predetermined angle and linear pressure, at the stop position A of the intermediate transfer belt 80, a streak is formed in the longitudinal direction. In this state, residual toner (hereinafter referred to as residual toner streak T) containing paper powder (not shown) of the transfer material P is accumulated.

  In the present embodiment, when the restart of the intermediate transfer belt 80 is requested from the engine controller of the image forming apparatus, the intermediate transfer belt 80 is first rotated in the reverse direction (the direction of arrow d in FIG. 4) (timing in FIG. 5). 1). Here, the amount of rotational movement of the intermediate transfer belt 80 in the reverse direction is from the cleaning blade tip to the squeeze sheet tip so as not to scatter toner into the apparatus. Next, the intermediate transfer belt 80 is rotated in the normal movement direction e without stopping at the stop position A before the start of the intermediate transfer belt 80 (timing 2 in FIG. 5).

  In the present embodiment, when this operation is performed once, the amount that the intermediate transfer belt 80 moves in the reverse direction d is 5 mm, which is equal to the distance from the front end of the cleaning blade to the front end of the squeeze sheet. Here, the process speed of the image forming apparatus is 117 mm / sec, which is equal to the rotational speed of the intermediate transfer belt 80. The rotational speed in the reverse direction is equal to the rotational speed in the forward direction rotation, and the time until returning to the stop position is 85 mm / sec.

  In the reverse rotation operation at the time of starting of the intermediate transfer belt 80 according to the above-described embodiment, the rotation speed is the same as the rotation speed of the intermediate transfer belt 80 when the intermediate transfer belt 80 rotates in the forward direction from the timing 1 shown in FIG. However, when the rotational speed of the intermediate transfer belt 80 during the reverse rotation operation increases in a stepwise manner from timing 1 to timing 2 in FIG. 5, or after timing 2 in FIG. The same effect can be obtained even when the residual toner streak T increases stepwise before reaching the stop position A before activation. This is because the sliding load between the edge portion 301a and the intermediate transfer belt 80 can be reduced even when the load on the cleaning blade tip edge portion 301a during reverse rotation and when normal rotation is resumed.

  The above is the reverse rotation operation at the time of starting the intermediate transfer member. With this operation, the residual toner streak T once moves in the upstream direction on the intermediate transfer belt 80 by a predetermined amount. Accordingly, the paper dust contained in the residual toner streak T is also scraped off by the cleaner blade 301 at the same time. Another example in which the reverse rotation operation of the intermediate transfer belt is effective is a case where the internal temperature of the image forming apparatus is extremely increased due to continuous use for a long time and the hardness of the cleaning blade 301 is decreased. At such time, the leading edge 301b of the cleaning blade 301 turns over as shown in FIG. Normally, if the intermediate transfer belt 80 rotates in the normal direction while leaving this state, it will be completely turned over, and the cleaner device will be replaced. In this case, it is possible to recover the turning-up cleaning blade 301 to an ideal contact state by performing the reverse rotation operation at the time of startup.

  As described above, according to this embodiment, when the intermediate transfer belt is started, the posture of the removable belt cleaning device is corrected to an ideal state, and good cleaning can be obtained. The reverse rotation operation at the time of starting the intermediate transfer belt in the present embodiment is controlled to be executed every time the intermediate transfer belt is started, and various images resulting from the belt cleaner 30 are caused by the reverse rotation at the time of starting the intermediate transfer belt. Defects can be prevented.

<Embodiment 2>
This embodiment is another example related to the reverse rotation at the start-up of the intermediate transfer belt 80 described in the first embodiment, and the intermediate transfer belt 80 and the photosensitive drums 70Y, 70M, 70C, and 70K are slid during the reverse rotation operation. The control of the image forming apparatus that has a mechanism that does not rub and that can provide a more stable and good cleaning for a long time will be described. The main body configuration and the like are the same as those in the first embodiment except that the photosensitive drums 70Y, 70M, 70C, and 70K in FIG. 1 can be separated from the intermediate transfer belt 80 at a predetermined timing.

  In the reverse rotation operation at the start-up of the intermediate transfer belt 80 described in the first embodiment, the photosensitive drums 70Y, 70M, 70C, and 70K that are in contact with the intermediate transfer belt 80 are subjected to load torque in the reverse direction f. When the number of reverse rotation operations is increased, the intermediate transfer belt 80 and the photoconductive drums 70Y, 70M, 70C, and 70K may be rubbed and the lifetime may be shortened. As a means for solving the above problem, it is conceivable that the intermediate transfer belt 80 is separated from the photosensitive drums 70Y, 70M, 70C, and 70K every time the intermediate transfer belt 80 is reversely rotated at the start-up. This will be described below with reference to FIG. 7 which is a schematic configuration diagram of the present embodiment and FIG. 8 which is a control timing chart. In FIG. 8, as in FIG. 5, it is assumed that the horizontal axis is the time axis, the upward direction of the vertical axis is rotated in the moving direction during image formation (hereinafter referred to as the positive direction), and the downward direction is the same. Suppose that it is rotating in the opposite direction.

  In the present embodiment, when the restart of the intermediate transfer belt 80 is requested from the engine controller of the image forming apparatus, the intermediate transfer belt 80 is first rotated in the reverse direction (in the direction of arrow d in FIG. 7) by the same amount as in the first embodiment. At the same time, in order to make the load torque applied to the photosensitive drum zero, the distance g is separated upward from the intermediate transfer belt 80 (timing 1 in FIG. 8). Here, the amount of rotational movement of the intermediate transfer belt 80 in the reverse direction is set from the cleaning blade tip to the squeeze sheet tip so that toner does not scatter into the apparatus, as in the first embodiment. Next, the intermediate transfer belt 80 is rotated in the normal movement direction e (timing 2 in FIG. 8).

  In the above-described embodiment, the control is performed to separate the photosensitive drum from the intermediate transfer belt from timing 1 to timing 2 in FIG. However, in accordance with the rotation direction of the intermediate transfer belt 80 during the reverse rotation operation, the photosensitive drum rotates reversely with the intermediate transfer belt 80 between timing 1 and timing 2 in FIG. 8, and after timing 2 in FIG. The effect can be obtained even when the photosensitive drum is rotated in the forward direction. This is because the load torque applied to the photosensitive drum can be reduced by rotating the photosensitive drum in the same manner during the reverse rotation of the intermediate transfer belt 80.

  As described above, in the present embodiment, a mechanism is provided in which the intermediate transfer belt 80 and the photosensitive drums 70Y, 70M, 70C, and 70K do not rub against each other during the reverse rotation operation when the intermediate transfer belt 80 is started up, and more stably for a long time. Good cleaning is obtained.

<Embodiment 3>
In this embodiment, the reverse rotation operation is performed by performing the reverse rotation operation at the time of starting the image carrier only when the image carrier starts up only after the removable blade cleaning device comes into contact from the separated state. The control of the image carrier that makes it possible to reduce the stress on the cleaning blade and to suppress the throughput reduction in the image forming apparatus will be described. The configuration of the main body is such that the image forming apparatus adds a switch for detecting whether the cleaning blade is in contact with or separated from the intermediate transfer belt in the first embodiment.

  In the present embodiment, as shown in FIG. 9, a push switch 802a is provided on the boss 802, which is the positioning member of the belt cleaner 30 in FIG. ON when pressed by the latch 308 of the belt cleaner 30 (a state in which the intermediate transfer belt 80 and the belt cleaner 30 are in contact with each other, FIG. 9A), otherwise OFF (the intermediate transfer belt 80 and the belt cleaner 30 are in contact with each other). In a separated state, the boss is provided with a switch function recognized by the engine controller in FIG. 9B. That is, the switch functions as a mechanical flag sensor that determines whether the cleaning blade is in a contact state or a separation state, in addition to a role as a member for positioning the belt cleaner 30. Accordingly, when the image forming apparatus is activated, the engine controller associated with the switch 805 detects that the switch has changed from OFF to ON, and the belt cleaner 30 is brought into the contact state from the separated state. Can be detected.

  FIG. 10 is a flowchart of the control for performing the reverse rotation operation at the start of the intermediate transfer belt 80 only when the image carrier is started for the first time when the removable blade cleaning device of the present embodiment is in the contact state from the separated state. It explains along.

  First, in step 1, the engine controller receives a request for starting the intermediate transfer belt. Next, in step 2, the engine controller checks whether the signal of the latch switch is ON or OFF. Here, if the signal is ON, the belt cleaner is in contact with the intermediate transfer belt, and the process proceeds to the next step 4. If it is OFF, the belt cleaner is not correctly mounted, and therefore the activation of the intermediate transfer belt is not permitted by the engine controller (step 3). In step 4, the engine controller confirms whether the latch switch immediately before confirming the latch switch in step 3 is ON or OFF. Here, when the latch switch is OFF, the belt cleaner 30 is in the contact state from the separated state, and only in this state, the reverse rotation operation at the time of starting the intermediate transfer belt shown in the first embodiment is performed.

  As described above, the detachable blade cleaning device is not stable in the contact state as compared with the fixed blade cleaning device as described above. In many cases, it becomes the worst state when the intermediate transfer belt is started for the first time when the belt cleaner 30 is brought into the contact state from the separated state. Therefore, the reverse rotation control at the time of starting of the intermediate transfer belt according to the present embodiment is highly likely to be in the worst state, but only when the intermediate transfer belt is started for the first time from the separated state to the contact state. Therefore, it is possible to reduce the stress on the cleaning blade mode due to the reverse rotation operation and to reduce the throughput in the image forming apparatus.

  The present invention is applicable to an image forming apparatus such as a copying machine or a printer that employs an electrophotographic system or an electrostatic recording system.

It is explanatory drawing of an image forming apparatus. It is a schematic diagram of a blade cleaning system. It is the figure which expanded the front side cross section of the removable belt cleaner of FIG. It is the figure which expanded the longitudinal cross section of the removable belt cleaner of FIG. It is a control timing chart of reverse rotation operation in Embodiment 1 of the present invention. It is an explanatory view of a characteristic cleaning device when the image forming apparatus is used continuously for a long time. It is a schematic block diagram of the image forming apparatus which concerns on Embodiment 2 of this invention. It is a control timing chart in Embodiment 2 of the present invention. It is a figure of the belt cleaner positioning boss | hub provided with the switch function. It is a flowchart regarding control of Embodiment 3 of the present invention.

Explanation of symbols

P transfer material T residual toner line 10 image forming station 12 primary charging roller 13 laser exposure device 14 developing device 16 drum cleaner 20 feeding roller 30 belt cleaner 301 cleaning blade 305 cleaner container 306 squeeze sheet 308 latch 40 fixing device 51 tension roller 55 secondary Transfer roller 70 Photosensitive drum 80 Intermediate transfer belt 802 Belt cleaner positioning boss

Claims (6)

An image carrier on which a toner image is formed, and a plate-like cleaning member that contacts the image carrier and cleans the surface thereof, and the plate-like cleaning member freely abuts on the image carrier and In the image forming apparatus capable of being separated,
When the rotation direction of the image carrier is the forward direction, the image carrier is rotated in the reverse direction by a predetermined amount and then rotated in the forward direction when the rotation of the image carrier is started. An image forming apparatus.   2. The image forming apparatus according to claim 1, wherein the rotation speed of the image carrier is increased stepwise when the image carrier is rotated in the reverse direction by a predetermined amount at the time of starting the rotation of the image carrier. .   Only when the image carrier is started immediately after the plate-shaped cleaning member comes into contact with the image carrier from a state of being separated from the image carrier, the image carrier is rotated in the reverse direction by a predetermined amount and then the normal direction. The image forming apparatus according to claim 1, wherein the image forming apparatus is rotated in a direction.   A first image carrier on which a toner image is formed; and a second image carrier on which the toner image is transferred from the first image carrier. The image forming apparatus according to claim 1, wherein the image carrier that can be used is the second image carrier.   5. The image forming apparatus according to claim 4, wherein the first image carrier is separated from the second image carrier during the reverse rotation operation at the time of starting the second image carrier.   5. The image formation according to claim 4, wherein the first image carrier is rotated in the reverse direction by the same amount as that of the second image carrier during the reverse rotation operation when the second image carrier is activated. apparatus.

Images