JP2009122182A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an image defect in a stripe state caused by a cleaning member with simple constitution without reversely rotating an image carrier. <P>SOLUTION: When a photoreceptor drum starts rotation from a stop state and an exposure device exposes the photoreceptor drum, exposure for exposing a position on the photoreceptor drum on which a cleaning blade abuts when the photoreceptor drum is in a stop state is corrected in the rotation cycle of the photoreceptor drum. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer having a function of forming an image on a recording medium such as a sheet.

  Conventionally, for example, the following cleaning apparatuses are known in an image forming apparatus that forms an image on a recording medium (for example, recording paper, OHP, etc.) using a transfer type electrophotographic process. That is, the developer image formed on the surface of the image carrier is transferred to a recording material as a recording medium, and then the developer remaining on the image carrier is removed (cleaned).

  Among these, a blade cleaning method is widely used.

  In the blade cleaning method, a cleaning blade having flexibility (rubber elasticity) is brought into contact with the image carrier in a predetermined pressure contact state as a cleaning member, and the surface of the image carrier is wiped away from above the image carrier. The remaining developer is removed by scraping. In order to improve the cleaning efficiency, the cleaning blade is generally brought into contact with the counter with respect to the rotation direction of the image carrier when the image carrier is formed.

  In such a system, when the image forming apparatus is in a stopped state (ie, when the image carrier rotation is stopped), the slipperiness of the image carrier surface area corresponding to the cleaning blade contact area (nip area) of the image carrier ( The friction coefficient μ) changes to a different state as compared to other image carrier surface areas. It is known that this causes a streak or image blur (density fluctuation or the like) on the image at the next image formation.

  The phenomenon of change in the slipperiness of the image carrier surface is caused by the fact that the developer pressed by the pressing force of the cleaning blade against the surface of the image carrier and the external additive released from the developer in the contact area are aggregated and fixed. It has been found that the slipperiness changes only in that part on the carrier. In general, the friction coefficient μ of the portion where the sliding property is changed (the portion where the friction is reduced) is lower than the friction coefficient μ of the other image carrier surface area.

  Therefore, when the image forming apparatus is driven again to rotate the image carrier, and the portion with the reduced friction coefficient comes into contact with the cleaning blade, the frictional force between the image carrier and the cleaning blade changes, The rotational speed of the image carrier changes faster. At this time, streaks of the image carrier rotation period and image blurring (density change, etc.) occur in the part where the image was formed on the image carrier and the part where the image was transferred to the recording medium.

  In order to fundamentally avoid the above problem, it is most certain to retract the cleaning blade from the image carrier surface when the image forming apparatus is stopped. However, in this case, the retraction mechanism is expensive. In addition, it is difficult to ensure the accuracy of the contact state, which leads to poor cleaning. As a result, the quality of the image is degraded. Further, when the cleaning blade is brought into contact again, there is a problem that it is necessary to make contact with the image carrier region that has been cleaned before retraction in order not to form an uncleaned region.

Therefore, conventionally, it has been proposed to remove the aggregated developer accumulated at the edge of the cleaning blade from the edge of the cleaning blade by rotating the image carrier backward when the image carrier is stopped. (See Patent Document 1).
JP-A-8-63071

  However, as in Patent Document 1, even if the image carrier is reversely rotated when the image carrier is stopped, it is not perfect.

  In other words, the fine toner and external additives staying in front of the edge of the cleaning blade aggregate and pass through the edge of the cleaning blade when the next image carrier starts to rotate, causing streak-like image defects. There was a possibility.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to prevent streak-like image defects caused by the cleaning member with a simple configuration without rotating the image carrier reversely. .

In order to achieve the above object, the present invention provides:
An image bearing rotator, and exposure means for exposing the image bearing rotator to form a latent image on the image bearing rotator, and the latent image formed on the image bearing rotator is developed by a developer. An image forming unit for visualizing and transferring the visualized developer image to a recording material;
A cleaning member provided in contact with the image bearing rotator to remove residual developer on the image bearing rotator;
In an image forming apparatus comprising:
When the image bearing rotator starts rotating from a stopped state, and the exposure means exposes the image bearing rotator, the image bearing rotary member is in contact with the cleaning member when the image bearing rotator is in the stopped state. Control means for correcting an exposure amount for exposing a position on the rotator with a rotation period of the image bearing rotator.

  According to the present invention, it is possible to prevent streak-like image defects caused by the cleaning member with a simple configuration without reversely rotating the image carrier.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. It is not intended to limit the scope to the following embodiments.

  The present invention relates to an image forming apparatus such as a copying machine or a printer that forms an image by an electrophotographic method or an electrostatic recording method. In particular, by bringing an elastic or flexible cleaning member such as a cleaning blade into contact with an image carrier (image carrier rotator) such as an electrophotographic photosensitive member or an electrostatic recording dielectric, the image carrier. The present invention relates to an image forming apparatus that removes the upper developer.

  FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to Embodiment 1 of the present invention. In this embodiment, a laser printer using an electrophotographic image forming process is shown as an example of an image forming apparatus.

The image forming apparatus forms an image forming unit 1a that forms a yellow image, an image forming unit 1b that forms a magenta image, an image forming unit 1c that forms a cyan image, and a black image. The image forming unit 1d includes four image forming units (image forming units). These four image formations 1a to 1d are arranged in a line at regular intervals.

  In each of the image forming units 1a to 1d, drum-type electrophotographic photosensitive members (hereinafter referred to as photosensitive drums) 2a to 2d as image carriers (image bearing rotating members) are installed. In each of the image forming units 1a to 1d, charging devices 3a to 3d, developing devices 4a to 4d, and drum cleaning devices 5a to 5d are installed around the photosensitive drums 2a to 2d, respectively. Further, exposure devices 6a to 6d as exposure means are respectively installed above the charging device 3 and the developing device 4. Each of the developing devices 4a to 4d contains yellow toner, magenta toner, cyan toner, and black toner.

  Each of the photosensitive drums 2a to 2d is a negatively charged OPC photosensitive member having a photoconductive layer on an aluminum drum base, and is rotationally driven clockwise at a predetermined process speed by a driving device (not shown). . The charging devices 3a to 3d as charging means uniformly charge the surfaces of the photosensitive drums 2a to 2d to a predetermined negative potential by a charging bias applied from a charging bias power source (not shown).

  The developing devices 4a to 4d attach toners of respective colors to the electrostatic latent images formed on the photosensitive drums 2a to 2d, respectively, and develop (visualize and visualize) toner images (developer images). As a developing method using the developing devices 4a to 4d, for example, toner particles mixed with a magnetic carrier are used as a developer, conveyed by magnetic force, and developed in contact with the photosensitive drums 2a to 2d. Component contact development can be used.

  The transfer rollers 7a to 7d as transfer means are composed of elastic members, and each photosensitive drum 2a to 2d is passed through an endless belt-like recording material conveying belt (hereinafter referred to as a transfer belt) 8 at each transfer nip. Abut. Here, the transfer roller 7 is used as the transfer means, but a transfer blade that is applied with a high pressure when the toner image is transferred onto the recording material and contacts the transfer belt 8 may be used.

  In the exposure devices 6a to 6d, laser light modulated in response to time-series electric digital pixel signals of image information is output from a laser output unit (not shown) and is rotated through a polygon mirror (not shown) that rotates at high speed. The surfaces of the photosensitive drums 2a to 2d are exposed. As a result, the exposure devices 6a to 6d form electrostatic latent images (latent images) of respective colors according to the image information on the surfaces of the photosensitive drums 2a to 2d charged by the charging devices 3a to 3d.

  The transfer belt 8 is stretched between the drive roller 9 and the tension roller 10 and is rotated (moved) in the direction of the arrow shown in FIG. The transfer belt 8 is made of a dielectric resin such as a polycarbonate, a polyethylene terephthalate resin film, a polyvinylidene fluoride resin film, or the like.

  A fixing device 13 having a fixing film 11 including a heat source and a pressure roller 12 is installed on the downstream side of the transfer belt 8 in the recording material conveyance direction.

  Hereinafter, an image forming operation by the image forming apparatus according to the present embodiment will be described.

  When the image formation start signal is issued, the photosensitive drums 2a to 2d of the image formations 1a to 1d that are rotationally driven at a predetermined process speed are uniformly charged to the negative polarity by the charging devices 3a to 3d, respectively.

  Next, each of the exposure devices 6a to 6d converts an image signal of the output image into an optical signal by a laser output unit (not shown), and the converted laser signal is converted into each charged photosensitive drum 2a. .About.2d are each exposed to scanning. As a result, an electrostatic latent image is formed on each of the photosensitive drums 2a to 2d (on the image bearing rotating body).

  First, the electrostatic latent image formed on the photosensitive drum 2a is attached with yellow toner by the developing device 4a to which a developing bias having the same polarity as the charging polarity (negative polarity) of the photosensitive drum 2a is applied. Visualized as an image.

  Thereafter, the recording material P fed from the feeding cassette 14 through the recording material conveyance guide 15 is synchronized with the timing at which the front end of the toner image on the photosensitive drum 2a is moved to the transfer portion between the photosensitive drum 2a and the transfer roller 7a. Then, it is conveyed to the transfer section by the registration roller 16. In the transfer unit, a yellow toner image is transferred onto the conveyed recording material P by the transfer roller 7a to which a transfer bias (positive polarity opposite to that of the toner) is applied.

  The recording material P to which the yellow toner image is transferred is moved to the image forming unit 1b by the recording material conveyance belt 8. In the transfer unit constituted by the image forming unit 1b and the transfer roller 7b, the magenta toner image formed on the photosensitive drum 2b in the same manner as described above is superimposed on the yellow toner image on the recording material P. Transcribed.

  In the same manner, cyan and black toner images formed on the photosensitive drums 2c and 2d of the image forming units 1c and 1d on the yellow and magenta toner images superimposed and transferred onto the recording material P are similarly transferred to the transfer units. In this way, a full color toner image is formed on the recording material P.

  The recording material P on which the full-color toner image is formed is conveyed to the fixing device 13, and the full-color toner image is heated and pressed at the fixing nip between the fixing film 11 and the pressure roller 12 to heat the surface of the recording material P. After fixing, the paper is discharged onto a discharge tray 18 by a discharge roller 17. Thus, a series of image forming operations is completed.

  When the image is transferred from the photosensitive drum to the recording material, the transfer residual toner (residual developer) remaining on the photosensitive drums 2a to 2d is removed and collected by the drum cleaning devices 5a to 5d, respectively. Is done.

  The drum cleaning devices 5a to 5d are devices that employ a blade cleaning method using cleaning blades 5a1 to 5d1 having flexibility (rubber elasticity) as cleaning members. The cleaning blades 5a1 to 5d1 are brought into contact in the counter direction with respect to the positive rotation direction (clockwise in FIG. 1) that is the rotation direction of the photosensitive drums 2a to 2d during image formation (operation). The toner remaining on the photosensitive drums 2a to 2d is wiped off.

  In FIG. 1, reference numerals 5a2 to 5d2 denote waste toner storage containers, and the toner scraped from the photosensitive drums 2a to 2d by the cleaning blades 5a1 to 5d1 is transferred to the waste toner storage containers 5a2 to 5d2 by a conveyance member (not shown). Sent and stored.

  In such a system, when the image forming apparatus is stopped (that is, when the photosensitive drum rotation is stopped), the slip property (friction coefficient μ) of the surface area of the photosensitive drum corresponding to the cleaning blade contact area (nip area) of the photosensitive drum is increased. It changes to a different state as compared with other photosensitive drum surface areas. It is known that this may cause streaks (density fluctuation or the like) on the image at the next image formation.

  The phenomenon of change in slipperiness on the surface of the photosensitive drum is caused by the toner pressed by the pressing force of the cleaning blade against the photosensitive drum and the external additive released from the toner in the contact area being agglomerated and fixed. The slipperiness is changed only in that part of the. Then, the friction coefficient μ of the portion where the sliding property is changed (the portion where the friction is reduced) is lower than the friction coefficient μ of the other photosensitive drum surface area.

  Therefore, when the image forming apparatus is driven again and the photosensitive drum rotates and the portion with the reduced friction coefficient comes into contact with the cleaning blade, the frictional force between the photosensitive drum and the cleaning blade changes, and the photosensitive drum The rotation speed of changes faster. At that time, streak-like image defects may occur in the rotation period of the photosensitive drum in the portion where the image is formed on the photosensitive drum and the portion where the image is transferred to the recording medium.

  This is presumably because the rotational speed of the photosensitive drum changes faster, so that the exposure amount of the region (part) changed faster on the photosensitive drum surface changes, that is, the exposure amount decreases. .

  Therefore, in this embodiment, the following control is performed in order to prevent streak-like image defects caused by the cleaning blade.

  That is, as described above, streak-like image defects caused by the cleaning blade occur at the photosensitive drum rotation cycle when the photosensitive drum starts rotating for image formation from the stopped state, and therefore the exposure amount at the rotation cycle. Apply correction to. The position where the exposure amount is corrected is the position on the photosensitive drum where the cleaning blade is in contact with the photosensitive drum being stopped.

  FIG. 2 is a diagram for explaining a schematic configuration of the image forming apparatus according to the present exemplary embodiment. FIG. 3 is a diagram for explaining the exposure timing in this embodiment.

  In the present embodiment, the photosensitive drums 2a to 2d, the charging devices 3a to 3d, the developing devices 4a to 4d, and the exposure devices 6a to 6d are connected to the main body control unit 19 and input from a host device 20 such as a computer. Control for image formation is performed based on the obtained image information. The main body control unit 19 is connected with a time measuring means, that is, a timer 21. The timer 21 measures the time during which the photosensitive drums 2a to 2d are stopped and the time during which the photosensitive drums 2d are rotating, and the main body control unit 19 stores the information. Here, the main body control unit 19 constitutes a control unit and a determination unit. The timer 21 and the main body control unit 19 constitute detection means.

  In this embodiment, the photosensitive drums 2a to 2d are driven at a speed of one rotation per second. Accordingly, when the photosensitive drums 2a to 2d start to rotate for image formation from the stopped state, the main body control unit 19 performs an exposure apparatus so as to correct the original (normal) exposure amount every second from the time of rotation. 6a to 6d are controlled. In this embodiment, the rotational speed of the photosensitive drums 2a to 2d is 100 mm / s, and the contact area (nip width) between the photosensitive drums 2a to 2d and the cleaning blades 5a1 to 5d1 is about 1 mm. Therefore, the exposure amount to be corrected was 10% higher than the original exposure amount by 9 ms every second as shown in the timing chart of FIG. As a result, the exposure amount per unit area can be maintained even when the rotational speed of the photosensitive drum is increased.

  In addition, when the rotational speed of the photosensitive drum is increased, a phenomenon occurs in which the rotational speed is decreased by the reaction thereafter. For this reason, in this embodiment, the exposure amount is increased by 10% less than the original exposure amount by 11 ms after increasing the exposure amount. Thereby, the exposure amount per unit area can be maintained even if the rotational speed of the photosensitive drum is slow.

  As a result, when the exposure amount is not corrected, a streak-like image defect may occur, whereas in this embodiment, a good image without a streak-like image defect can be obtained. I understood.

  As described above, according to the present embodiment, streak-like image defects caused by the cleaning blade can be prevented with a simple configuration without providing a mechanism or control means for rotating the photosensitive drum in the reverse direction.

  Example 2 of the present invention will be described below. In the present embodiment, only the components different from those in the first embodiment will be described, and the description of the same components as those in the first embodiment will be omitted.

  There is a concern that the degree of streak-like image defects caused by the cleaning blade becomes worse as the amount of toner accumulated between the photosensitive drum and the cleaning blade or the amount of external additive released from the toner increases. As the image forming time is longer, the amount is accumulated.

  Therefore, in this embodiment, the rotation time before the photosensitive drum stops, that is, the rotation time when the rotation operation is performed immediately before the photosensitive drum is in the stopped state, when the image is formed again from the stopped state. Control to increase the exposure amount to be corrected is performed.

  In this embodiment, the schematic configuration of the image forming apparatus is the same as that of the first embodiment. Therefore, when the photosensitive drums 2a to 2d start rotating for image formation from the stopped state, the main body control unit 19 starts from the time of rotation. A correction is made to the original exposure amount every second.

  Hereinafter, the exposure amount to be corrected will be described. FIG. 4 is a flowchart showing exposure amount correction in this embodiment.

  As shown in FIG. 4, when the rotation time of the photosensitive drums 2a to 2d before the stop is 10 minutes or longer (a predetermined time or longer, Yes in S11), the exposure amount to be corrected is 20% higher than the original exposure amount. Control is performed so that the exposure (second exposure amount) is 8 ms. Thereafter, the exposure is controlled to be 13 ms with an exposure amount 20% smaller than the original exposure amount (S12).

  Further, when the rotation time is less than 10 minutes (No in S11), the exposure is controlled to be 9 ms with an exposure amount (first exposure amount) 10% higher than the original exposure amount, and then 10 times more than the original exposure amount. The exposure was controlled to be 11 ms with a small exposure amount (S13).

  As a result, it has been found that a good image without streak-like image defects can be obtained regardless of the rotation time of the photosensitive drum before stopping.

  As described above, according to the present embodiment, streak-like image defects caused by the cleaning blade can be prevented with a simple configuration without providing a mechanism or control means for rotating the photosensitive drum in the reverse direction.

  Example 3 of the present invention will be described below. In the present embodiment, the different components from the first embodiment will be described, and the description of the same components as those in the first embodiment will be omitted.

  There is a concern that the streak-like image defect caused by the cleaning blade becomes worse as the toner accumulated between the photosensitive drum and the cleaning blade or the external additive released from the toner aggregates. The agglomeration is more agglomerated as the stop time after the photosensitive drum rotates is longer.

  Therefore, in this embodiment, control is performed to increase the exposure amount to be corrected when the image is formed again according to the stop time when the photosensitive drum stops from the rotating state.

  In this embodiment, the schematic configuration of the image forming apparatus is the same as that of the first embodiment. Therefore, when the photosensitive drums 2a to 2d start rotating for image formation from the stopped state, the main body control unit 19 starts from the time of rotation. A correction is made to the original exposure amount every second.

  Hereinafter, the exposure amount to be corrected will be described. FIG. 5 is a flowchart showing exposure amount correction in this embodiment.

  As shown in FIG. 5, when the stop time of the photosensitive drums 2a to 2d is 3 minutes or longer (a predetermined time or longer, Yes in S21), the exposure amount to be corrected is 20% higher than the original exposure amount. Control is performed so that the exposure (second exposure amount) is 8 ms. Thereafter, control is performed such that the exposure is performed for 13 ms with an exposure amount 20% smaller than the original exposure amount (S22).

  If the stop time is less than 3 minutes (No in S21), the exposure is controlled to be 9 ms with an exposure amount (first exposure amount) 10% larger than the original exposure amount, and then 10 times more than the original exposure amount. Control is performed so that exposure is performed for 11 ms with a small exposure amount (S23).

  As a result, it has been found that a good image without streak-like image defects can be obtained irrespective of the stop time of the photosensitive drum at the time of stop.

  As described above, according to the present embodiment, streak-like image defects caused by the cleaning blade can be prevented with a simple configuration without providing a mechanism or control means for rotating the photosensitive drum in the reverse direction.

  Example 4 of the present invention will be described below. In the present embodiment, only the components different from those in the first embodiment will be described, and the description of the same components as those in the first embodiment will be omitted.

  The streak-like image defect caused by the cleaning blade becomes better according to the drum rotation time when the photosensitive drum is re-formed from the stopped state. Therefore, in this embodiment, control is performed to reduce the exposure amount to be corrected when the image is formed again according to the rotation time from the stop state of the photosensitive drum.

  In this embodiment, the schematic configuration of the image forming apparatus is the same as that of the first embodiment. Therefore, when the photosensitive drums 2a to 2d start rotating for image formation from the stopped state, the main body control unit 19 starts from the time of rotation. A correction is made to the original exposure amount every second.

  Hereinafter, the exposure amount to be corrected will be described. FIG. 6 is a flowchart showing exposure amount correction in this embodiment.

As shown in FIG. 6, when the rotation time of the photosensitive drums 2a to 2d from the stopped state is less than 5 minutes (Yes in S31), the exposure amount to be corrected is 20% larger than the original exposure amount (second exposure). The exposure is controlled so that the exposure is 8 ms. Thereafter, control is performed such that the exposure is performed for 13 ms with an exposure amount 20% smaller than the original exposure amount (S32).

  Further, when the rotation time is 5 minutes or more (predetermined time or more, No in S31), the exposure is controlled to be 9 ms with an exposure amount (first exposure amount) 10% larger than the original exposure amount, and thereafter the original exposure amount is controlled. Control is performed so that exposure is performed for 11 ms with an exposure amount 10% smaller than the exposure amount (S33).

  As a result, it has been found that a good image without streak-like image defects can be obtained regardless of the rotation time of the photosensitive drum from the stopped state.

  As described above, according to the present embodiment, streak-like image defects caused by the cleaning blade can be prevented with a simple configuration without providing a mechanism or control means for rotating the photosensitive drum in the reverse direction.

  Example 5 of the present invention will be described below. In the present embodiment, only the components different from those in the first embodiment will be described, and the description of the same components as those in the first embodiment will be omitted.

  There is a concern that streaky image defects caused by the cleaning blade become worse as the amount of toner accumulated between the photosensitive drum and the cleaning blade and the amount of external additive released from the toner increases. And the amount will accumulate, so that the temperature of an environment is low.

  Therefore, in this embodiment, in accordance with the environmental temperature outside the image forming apparatus detected by the environment sensor 22, control is performed to increase the exposure amount to be corrected when the image is formed again from the stopped state. Here, the environment sensor 22 and the main body control unit 19 constitute a temperature detecting means.

  In this embodiment, the schematic configuration of the image forming apparatus is the same as that of the first embodiment. Therefore, when the photosensitive drums 2a to 2d start rotating for image formation from the stopped state, the main body control unit 19 starts from the time of rotation. A correction is made to the original exposure amount every second.

  Hereinafter, the exposure amount to be corrected will be described. FIG. 7 is a flowchart showing exposure amount correction in this embodiment.

  As shown in FIG. 7, when the environmental temperature is lower than 15 ° C. (Yes in S41), the exposure amount to be corrected is such that the exposure amount (second exposure amount) is 20% higher than the original exposure amount for 8 ms. To control. Thereafter, the exposure is controlled to be 13 ms with an exposure amount 20% smaller than the original exposure amount (S42).

  If the environmental temperature is 15 ° C. or higher (predetermined temperature or higher, No in S41), the exposure is controlled to be 9 ms with the exposure amount (first exposure amount) 10% higher than the original exposure amount, and then the original Control is performed so that exposure is performed for 11 ms with an exposure amount 10% less than the exposure amount (S43).

  As a result, it was found that a good image having no streak-like image defect can be obtained regardless of the environmental temperature.

  As described above, according to the present embodiment, streak-like image defects caused by the cleaning blade can be prevented with a simple configuration without providing a mechanism or control means for rotating the photosensitive drum in the reverse direction.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to Embodiment 1 of the present invention. 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 3 is a timing chart of exposure in Embodiment 1 of the present invention. The figure which shows the flowchart of exposure amount correction | amendment in Example 2 of this invention. The figure which shows the flowchart of exposure amount correction | amendment in Example 3 of this invention. The figure which shows the flowchart of exposure amount correction | amendment in Example 4 of this invention. The figure which shows the flowchart of exposure amount correction | amendment in Example 5 of this invention.

Explanation of symbols

1a to 1d Image forming unit 2a to 2d Photosensitive drum 3a to 3d Charging device 4a to 4d Developing device 5a to 5d Drum cleaning device 5a1 to 5d1 Cleaning blade 6a to 6d Exposure device 7a to 7d Transfer roller 19 Main body control unit

Claims (10)

An image bearing rotator, and exposure means for exposing the image bearing rotator to form a latent image on the image bearing rotator, and the latent image formed on the image bearing rotator is developed by a developer. An image forming unit for visualizing and transferring the visualized developer image to a recording material;
A cleaning member provided in contact with the image bearing rotator to remove residual developer on the image bearing rotator;
In an image forming apparatus comprising:
When the image bearing rotator starts rotating from a stopped state, and the exposure means exposes the image bearing rotator, the image bearing rotary member is in contact with the cleaning member when the image bearing rotator is in the stopped state. An image forming apparatus comprising: a control unit that corrects an exposure amount for exposing a position on a rotator with a rotation period of the image bearing rotator. A detection means for detecting a rotation time when the image carrying rotator is rotating;
When the image carrying rotator starts to rotate from the stopped state, the control means detects the rotation time when the image carrying rotator performs the rotation immediately before the image carrying rotator is in the stopped state. The image forming apparatus according to claim 1, wherein the exposure amount to be corrected is changed based on the above. A determination means for determining whether or not the rotation time detected by the detection means is a predetermined time or more;
When the determination means determines that the rotation time is not equal to or longer than the predetermined time, the control means sets the exposure amount to be corrected as a first exposure amount that is larger than the normal exposure amount,
3. The exposure amount to be corrected is set to a second exposure amount larger than the first exposure amount when the determination unit determines that the rotation time is equal to or longer than the predetermined time. The image forming apparatus described. Detecting means for detecting a stop time when the image bearing rotating body is in a stop state;
When the image bearing rotator starts to rotate from the stopped state, the control means corrects exposure based on the stop time when the image bearing rotator is in the stopped state, which is detected by the detecting means. The image forming apparatus according to claim 1, wherein the amount is changed. A determination means for determining whether or not the stop time detected by the detection means is a predetermined time or more;
The control unit, when the determination unit determines that the stop time is not equal to or longer than the predetermined time, the exposure amount to be corrected is a first exposure amount greater than the normal exposure amount,
5. The exposure amount to be corrected is set to a second exposure amount larger than the first exposure amount when the determination unit determines that the stop time is equal to or longer than the predetermined time. The image forming apparatus described. A detection means for detecting a rotation time when the image carrying rotator is rotating;
When the image bearing rotator starts rotating from a stopped state, the control means corrects the exposure amount based on the rotation time during which the image bearing rotator is rotating, detected by the detecting means. The image forming apparatus according to claim 1, wherein the image forming apparatus is changed. A determination means for determining whether or not the rotation time detected by the detection means is a predetermined time or more;
The control means sets the exposure amount to be corrected as a first exposure amount larger than a normal exposure amount when the determination unit determines that the rotation time is equal to or longer than the predetermined time,
The exposure amount to be corrected is set to a second exposure amount larger than the first exposure amount when the determination unit determines that the rotation time is not longer than the predetermined time. Image forming apparatus. Having temperature detection means for detecting the environmental temperature outside the image forming apparatus;
The image forming apparatus according to claim 1, wherein an exposure amount to be corrected is changed based on an environmental temperature detected by the temperature detection unit. A determination means for determining whether or not the environmental temperature detected by the temperature detection means is equal to or higher than a predetermined temperature;
When the control means determines that the environmental temperature is equal to or higher than the predetermined temperature, the control means sets the exposure amount to be corrected as a first exposure amount larger than a normal exposure amount,
9. The exposure amount to be corrected is set to a second exposure amount larger than the first exposure amount when the determination unit determines that the environmental temperature is not equal to or higher than the predetermined temperature. Image forming apparatus.   The control unit corrects the exposure amount by the exposure unit to the first exposure amount or the second exposure amount, and further corrects the exposure amount to be smaller than the normal exposure amount to obtain a normal exposure amount. The image forming apparatus according to claim 3, 5, 7, or 9.

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