JP4061926B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus using an electrophotographic process, and more particularly to an image forming apparatus capable of preventing image quality deterioration such as image flow by preventing deterioration of an image carrier.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an image forming apparatus using an amorphous silicon photoreceptor (hereinafter referred to as a-Si) drum (hereinafter simply referred to as a photoreceptor drum) as an image carrier is known. The photoconductor may be deteriorated by a discharge product generated by a corona charger (for example, a corona charger), and image quality defects such as image flow may occur during image formation.
[0003]
Specifically, when the photosensitive drum is charged by the charger, ozone is generated due to discharge by the charger. And an air component is decomposed | disassembled by ozone and ion products, such as a nitrogen oxide and a sulfur oxide, are produced | generated. When these ion products absorb moisture in the air and adhere to the surface of the photoreceptor drum from the charger, the electrical characteristics (resistance, etc.) of the photoreceptor deteriorate.
[0004]
The above-mentioned ion products are deposited in the charger, and when the image forming apparatus is stopped, that is, when the photosensitive drum is in a stationary state, the ion products deposited in the charger face the charger. It adheres to the surface of the photoreceptor. Considering that the surface roughness of the photosensitive member is about 0.1 μm, the ion product penetrates into the surface of the photosensitive member, and it is difficult to remove the ion product with a normal cleaning system.
[0005]
Further, considering that the above-mentioned ion product is water-soluble, the ion product adhering to the surface of the photoreceptor takes in moisture in the air, and the electrical resistance of the photoreceptor is further deteriorated. As a result, the surface of the photoreceptor is partially deteriorated, and when an image is formed, an image flow that is an image defect phenomenon occurs.
[0006]
In order to prevent the above problems, a heater is built in the photosensitive drum to evaporate the moisture taken in by the ion product. In this method, the ion product itself is removed. This is difficult, and the heater must be built in the photosensitive drum, which increases the cost.
[0007]
On the other hand, Japanese Patent Laid-Open No. 11-133645 discloses a method for removing ozone products by polishing the surface of a photoreceptor using a polishing toner mixed with an abrasive and a polishing means (a polishing roller and a cleaning blade). (Hereinafter referred to as Conventional Example 1).
[0008]
Furthermore, Japanese Patent Laid-Open No. 4-250472 describes a technique for preventing ion products such as discharge products from falling on the surface of the photoconductor and directly adhering to the surface of the photoconductor (hereinafter referred to as the following). Called Conventional Example 2). In Conventional Example 2, after the toner image is transferred and before the movement of the photosensitive drum is stopped, the surface of the photosensitive drum is charged by the corona charger, and the charged area is developed by the toner developer. is doing. Then, after the developed toner adsorption region is moved between the corona charger and the photosensitive drum, the movement of the photosensitive drum is stopped. This prevents the ion product from adhering directly to the surface of the photosensitive drum.
[0009]
In the method described in Japanese Patent Laid-Open No. 7-219402, when a series of image forming operations is completed, waste toner (untransferred toner) collected by the cleaning device is attached to a predetermined range on the surface of the photosensitive drum. The photosensitive drum is rotationally controlled so that the area of the photosensitive drum to which the waste toner is attached is positioned opposite to the corona charger (hereinafter referred to as Conventional Example 3). Thus, in Conventional Example 3, the ion product is prevented from adhering directly to the surface of the photosensitive drum.
[0010]
[Problems to be solved by the invention]
However, in Conventional Example 1, if the image forming apparatus is stopped and placed in a high-humidity atmosphere for a long time, the ion products are inevitably formed on the surface of the photosensitive drum (the surface facing the charger). ) And the ion product is combined with moisture in the air, and the electrical characteristics of the photosensitive drum are deteriorated. When the printing operation is performed, image quality defects such as image flow occur.
[0011]
Furthermore, in Conventional Example 2, each time the movement of the photosensitive drum is stopped (that is, every time the printing operation is finished), the photosensitive drum must be charged and exposed, and the surface of the photosensitive drum is covered with the toner layer. As a result, the toner consumption will inevitably increase. Further, when the surface of the photosensitive drum is covered with the toner layer, it is necessary to perform control for separating a cleaning mechanism such as a cleaning blade from the photosensitive drum, which complicates the control mechanism.
[0012]
On the other hand, in Conventional Example 3, in order to reduce toner consumption, a toner layer is formed using untransferred toner. However, in the method described in Conventional Example 3, the toner layer is uniformly formed in a predetermined range. Therefore, it is difficult to effectively prevent the ion product from adhering to the photosensitive drum.
[0013]
SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can effectively prevent an ion product from adhering to a photosensitive drum with a simple configuration with a small amount of toner consumption.
[0014]
[Means for Solving the Problems]
According to the present invention, a photosensitive member movable in a predetermined direction, a charger for charging the photosensitive member, and a downstream of the charger in the predetermined direction from the charger. A developing unit disposed; and a cleaning unit disposed downstream of the developing unit in the predetermined direction to remove residual toner, and moving the photoconductor in a predetermined direction. After charging the photoreceptor with a charger, an electrostatic latent image is formed according to image data, and the electrostatic latent image is developed with the developer to form a toner image on the photoreceptor to form an image. In the image forming apparatus to be performed,
A developing bias is applied to the developing device when the image forming is completed and the developing device is shifted to a predetermined state, and the photosensitive member is uncharged to give the photosensitive member a predetermined length in the predetermined direction. And a controller for controlling toner layer formation for positioning the toner layer at a position facing the charger after forming the toner layer, and a humidity sensor for measuring the atmospheric humidity in the apparatus. Even before the transition to a predetermined state, when the detected humidity detected by the humidity sensor is equal to or higher than a predetermined humidity, the toner layer formation control is performed.
Further, it is possible to obtain an image forming apparatus characterized in that the predetermined state is a low power consumption mode that shifts when a predetermined time elapses after the image formation is completed .
[0015]
In this way, it is possible to prevent the ion product from adhering to the photosensitive drum with a simple configuration, and as a result, image quality such as image flow does not occur.
In addition, a humidity sensor that measures the atmospheric humidity is provided, and the control means detects the detected humidity detected by the humidity sensor even when the humidity is equal to or higher than the predetermined humidity even before shifting to the predetermined state. The toner layer formation control is performed. In this way, toner layer formation control can be selectively performed according to the atmospheric humidity.
[0016]
The predefined state is a low power consumption mode before Symbol image forming transitions when the time defined in advance after the end has passed. Specifically, when the power switch is turned off, the control means detects the operation of turning off the power switch, recognizes the predetermined state, executes the toner layer formation control, and turns off the power. To do. In this way, since the toner layer formation control is performed when the low power consumption mode is entered after a predetermined time has elapsed after the image formation is completed, the toner consumption can be reduced. Further, the toner consumption can be reduced even if the power is turned off after the toner layer formation control is executed when the power switch off operation is detected.
[0017]
Further, during the toner layer formation control, the control means controls the movement of the photoconductor in the predetermined direction to form the toner layer, and then reverses the photoconductor in the predetermined direction. In this direction, the toner layer is positioned at a position facing the charger. In this way, it is possible to prevent the ion product from adhering to the photosensitive drum with a simple configuration.
[0018]
In the toner layer formation control, the control means controls the movement of the photoconductor in a direction opposite to the predetermined direction to form the toner layer, and further moves the photoconductor in the reverse direction. The toner layer may be positioned at a position facing the charger by controlling movement in the direction. In this way, the toner layer can be positioned at a position facing the charger with a simple configuration in a short time.
[0019]
Note that a brake mechanism that brakes the photoconductor to position the toner layer at a position facing the charger may be provided. In this way, the toner layer can be accurately positioned at the position facing the charger.
[0021]
The length of the toner layer in the predetermined direction is at least longer than the length of the charger in the predetermined direction, and the image formation is performed after the toner layer formation control is performed. When the image forming mode is entered, the control means permits the image formation after moving the photoconductor in the predetermined direction until the toner layer is removed by the cleaning unit. In this way, it is possible to completely prevent the ion product from adhering to the photoreceptor from the charger, and the toner layer does not interfere with image formation.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings. It should be noted that the dimensions, materials, shapes, relative arrangements, etc. of the components described in the illustrated examples are not intended to limit the scope of the present invention, but are merely illustrative examples, unless otherwise specified. Absent.
[0023]
Referring to FIG. 1, the illustrated image forming apparatus includes a photosensitive drum (a-Si photosensitive drum: image carrier) 1, and sequentially along the outer periphery (rotation direction) of the photosensitive drum 1. A charger (for example, a corona charger) 2, a light source (exposure unit) 3, a developing roller 4, a transfer roller 5, a cleaning blade 9, and a static eliminator 10 are arranged. In the illustrated example, the photosensitive drum 1 can be rotated forward and backward, and the photosensitive drum 1 is rotated forward (moved in a predetermined direction) using a motor and a gear (not shown) as will be described later. ) And reversed.
[0024]
When image formation is performed, the photosensitive drum 1 is rotationally driven in the normal direction (in the direction indicated by the solid arrow in the figure) by a motor controlled by a control device (not shown). First, the removed photosensitive drum 1 is uniformly charged by the charger 2. The exposure unit 3 exposes the photosensitive drum 1 according to the image data, and forms an electrostatic latent image on the photosensitive drum. Thereafter, the electrostatic latent image is developed by the developing roller 4 to become a toner image. The developing roller 4 is provided in a developing device (not shown), and toner is supplied to the developing device from a toner supply device (not shown).
[0025]
Thereafter, the toner image on the photosensitive drum 1 is transferred as a transfer image to a transfer paper (recording paper) 11 by the transfer roller 5 and then fixed on the transfer paper 11 by a fixing device (not shown). Untransferred toner (residual toner) remaining on the photosensitive drum 1 is removed by the cleaning blade 9, recovered by a recovery device such as a recovery screw 8, and conveyed to a waste bottle (not shown). The photosensitive drum 1 is neutralized by the static eliminator 10 and then charged again, and image formation is performed in the same manner. The illustrated image forming apparatus includes a polishing roller (for example, a foamed EPDM roller) 6, and the surface of the photosensitive drum 1 is polished by the polishing roller 6 (the toner contains an abrasive). ing). During polishing, a predetermined load is applied to the surface of the photosensitive drum 1.
[0026]
When the preset time has elapsed after completion of the image formation (printing operation: image formation mode) performed as described above (that is, the static elimination is completed and the photosensitive drum 1 is stopped), the control device Shifts to a low power consumption mode (sleep mode: predetermined state). That is, the minimum power consumption mode is entered. Here, before shifting to the low power consumption mode, the control device performs toner layer formation control described later. In other words, when a preset time elapses, the control device performs toner layer formation control and then shifts to the low power consumption mode.
[0027]
Here, toner layer formation control will be described. As described above, after the completion of image formation (printing operation) (that is, the neutralization is completed and the photosensitive drum 1 is stopped), when a preset time elapses, the control device corrects the photosensitive drum 1. At the same time, a bias voltage (development bias) is applied to the developing roller 4. At this time, components other than the developing roller such as the charger 2, the exposure unit 3, the transfer roller 5, and the static eliminator 10 are not operated (that is, the charger 2, the exposure unit 3, the transfer roller 5, the static eliminator 10, etc.). All the components except the developing roller remain stopped). The developing roller 4 rotates following the rotation of the photosensitive drum 1 and the photosensitive drum 1 is in an uncharged state, but the toner layer (entire solid image) 7 is transferred to the photosensitive member by the developing roller 4 (and the developing bias). It is formed on the surface of the drum 1.
[0028]
The rotation direction length of the toner layer 7 (the length in the rotation direction of the photosensitive drum 1; hereinafter simply referred to as the toner layer width) depends on the rotation direction length of the charger 2 (hereinafter simply referred to as the charger width). It is determined. For example, if the charger width is A, the toner layer width is at least A. Desirably, the toner layer width is 2A.
[0029]
The rotational position of the photosensitive drum 1 (for example, a rotational angle based on a predetermined rotational position) is recognized by a detection sensor such as a rotation detector, and based on the diameter and rotational angle of the photosensitive drum 1. Knowing the amount of movement (moving length in the rotation direction) of the photosensitive drum 1 and rotating a predetermined angle after the formation of the toner layer is started, the control device stops applying the developing bias. Thus, a toner layer 7 having a predetermined width 2A is formed on the photosensitive drum 1. At this time, the control device stops the rotation of the motor and stops the rotation of the photosensitive drum 1.
[0030]
After the toner layer 7 is formed as described above, the control device reverses the motor to reverse the photosensitive drum 1 (in the direction indicated by the broken line arrow in FIG. 1). As described above, the control device recognizes the rotational position of the photosensitive drum 1, and when the toner layer 7 formed on the photosensitive drum 1 is positioned directly below the charger 2, Stop rotation drive. At this time, as shown in FIG. 2, it is desirable that the photosensitive drum 1 is stopped at a position where the toner layer 7 extends A / 2 width from the end of the charger 2. In order to stop the photosensitive drum 1 so that the toner layer 7 is directly below the charger 2, a brake mechanism 21 shown in FIG. 3 is used here.
[0031]
The illustrated brake mechanism 21 includes a solenoid 21a, a spring member 21b, and a brake member 21c. One end of the spring member 21b is connected to the solenoid 21a, and the other end is connected to a support member (not shown). . On the other hand, the brake member 21c is, for example, a rectangular body, and its central portion is instructed to be rotatable by a fulcrum. One end of the rectangular body is connected to the spring member 21b, and a brake body (for example, a rubber body) 21d is attached to the other end surface (the surface facing the surface of the photosensitive drum 1). As will be described later, the photosensitive drum 1 is braked by the brake body 21d.
[0032]
During image formation, that is, when the photosensitive drum 1 is rotating forward (in the direction indicated by the solid line arrow in FIG. 3), the solenoid 21a is turned off, and the brake member 21c is caused by the elastic force of the spring member 21b. Rotates counterclockwise around the fulcrum in the figure. As a result, the brake member 21c is retracted from the photosensitive drum 1.
[0033]
As described above, the toner layer 7 is formed on the photosensitive drum 1, the photosensitive drum 1 is reversed (in the direction indicated by the broken arrow), and is reversed by a predetermined amount (that is, formed on the photosensitive drum 1). When the toner layer 7 is positioned immediately below the charger 2, the control device stops the rotation of the motor and turns on the solenoid 21a. As a result of the solenoid 21a pulling the spring member 21b rightward in the figure against the elastic force of the spring member 21b, the brake member 21c rotates about the fulcrum clockwise in the figure. As a result, the photosensitive drum 1 is pressed by the brake member 21c (brake body 21d), and the photosensitive drum 1 is quickly stopped. In the example shown in FIG. 3, the forward and reverse directions of the photosensitive drum 1 are opposite to the forward and reverse directions of the photosensitive drum 1 shown in FIG. 1, but this is for convenience of explanation. There is a normal rotation direction when the image is formed. That is, after the photosensitive drum 1 is charged by the charger 2, exposure is performed by the light source 3 (not shown in FIG. 3), and the electrostatic latent image on the photosensitive drum 1 is developed by the developing roller 4 to form a toner image. The direction of forming is the normal rotation direction.
[0034]
If the brake mechanism 21 is used, the relative positional relationship between the toner layer 7 and the charger 2 can be accurately defined. However, as described above, the toner layer width is longer than the charger width. In this case, even if the stop position of the photosensitive drum 1 is slightly deviated, the toner layer 7 is positioned immediately below the charger 2, so the brake mechanism 21 is not essential.
[0035]
Thus, after positioning the toner layer 7 directly below the charger 2, the control device shifts to the low power consumption mode. In the low power consumption mode, since the toner layer 7 is positioned immediately below the charger 2, even if the ion product falls in a high humidity atmosphere, the toner layer 7 can be received. Thus, the ion product does not reach the surface of the photosensitive drum 1 (that is, the ion product does not adhere to the photosensitive drum 1 itself). As a result, the surface of the photosensitive drum 1 is not deteriorated by the ion product. In addition, since the toner layer 7 is formed when shifting to the low power consumption mode, the toner consumption can be reduced.
[0036]
When shifting from the low power consumption mode to the printing mode (image forming mode) in the above-described state, the control device stops the charger 2, the exposure unit 3, the developing roller 4, and the transfer roller 5, and the photosensitive drum. 1 is rotated once in the forward direction. As a result, the toner layer 7 is removed by the cleaning blade 9. Thereafter, normal printing is started (that is, the control device permits image formation).
[0037]
Here, a photosensitive drum 1 having a diameter of 40 mm × a length of 360 mm is used, a toner to which 3% of titanium oxide is added as an abrasive is used, and a foamed EPDM roller (outer diameter of 14 mm) is used as a polishing roller (rubbing roller). The photosensitive drum 1 was polished with a sponge thickness of 2.0 mm and a hardness of HS 35 degrees). During polishing, a load of 200 g / cm was applied to the surface of the photosensitive drum 1 by a foamed EPDM roller.
[0038]
Furthermore, when 30 minutes have passed after the end of the printing operation, the mode is set to shift to the low power consumption mode. When the mode is shifted to the low power consumption mode, the photosensitive drum 1 is rotated for 0.2 seconds and the developing bias is applied. Thereafter, when the photosensitive drum 1 is reversed for 0.25 seconds, the toner is The layer 7 was set so as to be positioned immediately below the charger 2.
[0039]
Under the set conditions described above, after printing 10,000 sheets in an atmosphere of 30 ° C. and 80% RH, the sheet was left for 8 hours in the low power consumption mode. When printing was performed again, no image flow occurred in the half image.
[0040]
On the other hand, for comparison, after printing 10,000 sheets in an atmosphere of 30 ° C. and 80% RH, the toner layer 7 was not formed on the photosensitive drum 1 and left in the low power consumption mode for 8 hours. During standing, an image flow occurred in a portion located directly under the charger 2, and so-called blur occurred in a part of the half image.
[0041]
In this way, if the toner layer 7 is positioned directly below the charger 2 when shifting to the low power consumption mode, image quality such as image flow does not occur when printing is resumed thereafter.
[0042]
In the above example, the photosensitive drum 1 is rotated forward to form a toner layer on the photosensitive drum 1, and then the photosensitive drum 1 is reversed to position the toner layer 7 directly below the charger 2. When the mode is shifted to the low power consumption mode, the photosensitive drum 1 may be reversed immediately and a developing bias may be applied to form the toner layer 7 on the photosensitive drum 1. Even after the toner layer 7 is formed, the photosensitive drum 1 is reversed to position the toner layer 7 directly below the charger 2.
[0043]
In this way, since the forward rotation operation is not required, that is, the photosensitive drum 1 may be reversed from the position of the developing roller 4 to the position of the charger 2, the toner layer 7 is charged in the charger 2 in a short time. Can be positioned directly below.
[0044]
In the above description, an example in which toner layer formation control is performed when shifting to the low power consumption mode has been described. For example, when the power switch is turned off (predetermined state), the power switch The power supply may be turned off after the control device senses off and the control device performs the toner layer formation control described above.
[0045]
Furthermore, by providing a humidity sensor in the device, when the humidity is predefined humidity above, to perform the toner layer formation control described above. In other words, even before the transition to the low power consumption mode, that is, before a predetermined time has elapsed after the end of printing, if the humidity exceeds the predetermined humidity, the toner layer formation described above is performed. control intends line.
[0046]
In the above example, an example in which a full solid image (image density 100%) is formed as a toner layer has been described. However, it is understood that image quality such as image flow does not occur when the image density is 90% or more. It was.
[0047]
In addition, for example, even when a heater is built in the photosensitive drum, the heater temperature can be reduced and the heater capacity can be reduced, resulting in energy saving.
[0048]
【The invention's effect】
As described above, according to the present invention, when shifting to a predetermined state after completion of image formation, a developing bias is applied to the developing device, and the photosensitive member is determined in advance in a non-charged state. After forming a toner layer having a predetermined length in a predetermined direction, the toner layer formation control is performed so that the toner layer is positioned at a position facing the charger. Can be prevented. As a result, there is an effect that image quality defects such as image flow do not occur.
Further, according to the present invention, since the toner layer formation control is performed when the detected humidity detected by the humidity sensor becomes equal to or higher than the predetermined humidity even before shifting to the predetermined state, the atmospheric humidity The toner layer formation control can be selectively performed according to the above.
[0049]
According to the present invention, since the predetermined state is the low power consumption mode that shifts when the predetermined time has elapsed after the image formation is completed, there is an effect that the toner consumption can be reduced. .
[0050]
According to the present invention, when the power switch is turned off, when the power switch off operation is detected, the power supply is turned off after the toner layer formation control is executed by recognizing a predetermined state. There is an effect that toner consumption can be reduced.
[0051]
According to the present invention, during toner layer formation control, the photosensitive member is controlled to move in a predetermined direction to form a toner layer, and then the photosensitive member is controlled to move in a direction opposite to the predetermined direction. Thus, since the toner layer is positioned at a position facing the charger, it is possible to prevent the ion product from adhering to the photosensitive drum with a simple configuration.
[0052]
According to the present invention, during toner layer formation control, the photosensitive member is controlled to move in a direction opposite to a predetermined direction to form a toner layer, and then the photosensitive member is further controlled to move in the opposite direction. Since the toner layer is positioned at the position facing the charger, there is an effect that the toner layer can be positioned at the position facing the charger in a short time and with a simple configuration.
[0053]
According to the present invention, since the brake mechanism for braking the photosensitive member and positioning the toner layer at a position facing the charger, the toner layer can be accurately positioned at the position facing the charger. There is.
[0055]
According to the present invention, since the length of the toner layer in the predetermined direction is at least longer than the length of the charger in the predetermined direction, it is possible to completely adhere the ion product from the charger to the photoreceptor. There is an effect that can be prevented.
[0056]
According to the present invention, after the toner layer formation control is performed, when the image forming mode for performing image formation is entered, the photosensitive member is moved in a predetermined direction until the toner layer is removed by the cleaning unit. Since image formation is permitted, this toner layer does not interfere with image formation.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating an example of an image forming apparatus according to the present invention.
FIG. 2 is a diagram illustrating a relationship between a charger and a toner layer in the image forming apparatus illustrated in FIG.
FIG. 3 is a diagram for explaining a brake mechanism used in the image forming apparatus shown in FIG. 1;
[Explanation of symbols]
1 Photosensitive drum (a-Si photosensitive drum)
2 Charger (Corona Charger)
3 Light source (exposure unit)
4 Development roller (developer)
5 Transfer roller 6 Polishing roller 7 Toner layer 8 Recovery screw 9 Cleaning blade 10 Static eliminator 11 Transfer paper (recording paper)

Claims (7)

A photosensitive member movable in a predetermined direction; a charger for charging the photosensitive member; and a developing device disposed downstream of the charger in the predetermined direction from the charger. A cleaning unit that is disposed downstream of the developing unit in the predetermined direction and removes residual toner, and the photosensitive member is moved by the charger while moving the photosensitive member in a predetermined direction. After charging, an electrostatic latent image is formed in accordance with image data, and the electrostatic latent image is developed by the developing unit to form a toner image on the photoreceptor to form an image. In the device
A developing bias is applied to the developing device when the image forming is completed and the developing device is shifted to a predetermined state, and the photosensitive member is uncharged to give the photosensitive member a predetermined length in the predetermined direction. And a controller for controlling the toner layer formation for positioning the toner layer at a position facing the charger after the toner layer is formed, and a humidity sensor for measuring the atmospheric humidity in the apparatus. Even before the transition to a predetermined state, when the detected humidity detected by the humidity sensor is equal to or higher than a predetermined humidity, the toner layer formation control is performed.
Further, the predetermined state is a low power consumption mode which shifts when a predetermined time elapses after the image formation is completed .   When the power switch is turned off, the control means recognizes the predetermined state upon detecting the power switch off operation and executes the toner layer formation control, and then turns off the power. The image forming apparatus according to claim 1.   In the toner layer formation control, the control means controls the movement of the photoconductor in the predetermined direction to form the toner layer, and then moves the photoconductor in a direction opposite to the predetermined direction. The image forming apparatus according to claim 1, wherein the toner layer is positioned at a position facing the charger by performing movement control.   In the toner layer formation control, the control means controls the movement of the photoconductor in a direction opposite to the predetermined direction to form the toner layer, and further moves the photoconductor in the reverse direction. The image forming apparatus according to claim 1, wherein the toner layer is positioned at a position facing the charger by movement control. The image forming apparatus according to claim 3 or 4, characterized in that it has a brake mechanism for positioning the toner layer by braking the photoreceptor in a position facing the charger.   The image forming apparatus according to claim 1, wherein the length of the toner layer in the predetermined direction is at least equal to or longer than the length of the charger in the predetermined direction.   After the toner layer formation control is performed, when the control unit shifts to an image formation mode in which the image formation is performed, the control unit removes the photoconductor in the predetermined direction until the toner layer is removed by the cleaning unit. The image forming apparatus according to claim 1, wherein the image formation is permitted after being moved.

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