JP7243369B2 - Development method and image forming apparatus - Google Patents

Description

The present disclosure relates to a developing method and an image forming apparatus.

Conventionally, a so-called cleanerless developing method using negatively charged toner is known. In the cleanerless development method, the developing roller supplies toner from the housing to the photosensitive drum, the transfer roller transfers the toner on the surface of the photosensitive drum to the sheet, and the charging roller removes residual toner. It includes a step of charging the surface of the photosensitive drum, and a step of recovering residual toner to a housing by a developing roller (see Patent Document 1 below).

JP 2006-11137 A

In the developing method described in Japanese Patent Laid-Open No. 2002-100000, filming may occur on the surface of the photosensitive drum as the number of printed sheets increases. If filming occurs on the surface of the photosensitive drum, image quality may deteriorate.

Accordingly, an object of the present disclosure is to provide a developing method and an image forming apparatus capable of recovering residual toner using a developing roller while suppressing filming on the surface of a photosensitive drum.

(1) The developing method of the present disclosure includes a step of supplying toner to a photosensitive drum from a housing capable of accommodating non-magnetic single-component negatively charged toner by a developing roller to which a negative developing bias is applied; The transfer roller to which a positive transfer bias is applied transfers the toner on the surface of the photosensitive drum to a sheet, and the residual toner on the surface of the photosensitive drum is peeled off by the peripheral speed difference between the roller and the photosensitive drum. The residual toner that has been removed from the surface of the photosensitive drum is negatively charged by a negative peeling roller bias that is greater in absolute value than the developing bias and is applied to the peeling roller. on the surface of the photosensitive drum; negatively charging the surface of the photosensitive drum with residual toner by a charging roller to which a negative charging bias having a larger absolute value than the peeling roller bias is applied; recovering the residual toner to the housing by the developing roller to which is applied.

According to such a method, residual toner adhering to the surface of the photosensitive drum is peeled off from the surface of the photosensitive drum by the peeling roller.

As a result, filming on the surface of the photosensitive drum can be suppressed.

Then, the residual toner peeled off from the surface of the photosensitive drum is charged by a peeling roller, attached to the surface of the photosensitive drum, and collected into the housing by a developing roller.

Therefore, there is no need to separately provide a container for collecting the residual toner.

In summary, residual toner can be collected using the developing roller while suppressing filming on the surface of the photosensitive drum.

(2) The residual toner charged by the peeling roller adheres to the surface of the photosensitive drum due to the potential difference with the surface of the photosensitive drum.

(3) The developing method includes the step of applying a positive transfer bias to the transfer roller and applying a peeling roller bias to the peeling roller after a predetermined first time elapses after applying the developing bias to the developing roller. and applying the developing bias to the developing roller after a lapse of a predetermined second time after applying the charging bias to the charging roller.

(4) The developing method is a step of forming an electrostatic latent image on the surface of the photosensitive drum by exposing the surface of the photosensitive drum charged by the charging roller before toner is supplied to the photosensitive drum by the developing roller. may further include

(5) The image forming apparatus of the present disclosure includes a housing, a photosensitive drum, a developing roller, a transfer roller, a peeling roller, and a charging roller. The housing can contain a non-magnetic one-component negatively charged toner. A toner image made of toner is formed on the surface of the photosensitive drum. A negative developing bias is applied to the developing roller. The developing roller can supply the toner in the housing to the surface of the photosensitive drum. A positive transfer bias is applied to the transfer roller. The transfer roller can transfer the toner image from the surface of the photosensitive drum to the sheet. A negative peeling roller bias having a larger absolute value than the developing bias is applied to the peeling roller. The peeling roller can peel off residual toner remaining on the surface of the photosensitive drum without being transferred to the sheet from the surface of the photosensitive drum due to the peripheral speed difference between the peeling roller and the photosensitive drum. The stripping roller negatively charges the stripped residual toner by a stripping roller bias, and attaches the charged residual toner to the surface of the photosensitive drum. A negative charging bias having a larger absolute value than the peeling roller bias is applied to the charging roller. The charging roller negatively charges the surface of the photosensitive drum with residual toner.

The image forming apparatus collects residual toner in the housing by a developing roller to which a developing bias is applied.

(6) The image forming apparatus may further include a controller. The controller applies a positive transfer bias to the transfer roller and a peeling roller bias to the peeling roller after a predetermined first time has elapsed after applying the developing bias to the developing roller. The control section applies the developing bias to the developing roller after a lapse of a predetermined second time after applying the charging bias to the charging roller.

(7) The image forming apparatus may further include an exposure device. The exposure device forms an electrostatic latent image on the surface of the photosensitive drum by exposing the surface of the photosensitive drum charged by the charging roller before toner is supplied to the photosensitive drum by the developing roller.

(8) The image forming apparatus may further include a charging cleaning roller. The charging cleaning roller cleans the charging roller.

(9) The charging cleaning roller may follow the charging roller. A negative cleaning bias having an absolute value equal to or less than the charging bias may be applied to the charged cleaning roller.

(10) The image forming apparatus may further include a cleaner member. The cleaner member contacts the charged cleaning roller and collects paper dust adhered to the charged cleaning roller.

(11) The peripheral speed of the charging cleaning roller and the peripheral speed of the charging roller may be different. A negative first cleaning bias having a smaller absolute value than the charging bias may be applied to the charging cleaning roller. A negative second cleaning bias having a smaller absolute value than the first cleaning bias may be applied to the cleaner member.

(12) The image forming apparatus may include a drum cartridge and a developer cartridge. A drum cartridge includes a photosensitive drum, a charging roller, and a peeling roller. The developer cartridge can be attached to the drum cartridge. The developing cartridge includes a housing and a developing roller.

(13) The drum cartridge may further include a transfer roller.

According to the developing method and image forming apparatus of the present disclosure, residual toner can be recovered using the developing roller while suppressing filming on the surface of the photosensitive drum.

FIG. 1 is a schematic configuration diagram of an image forming apparatus. FIG. 2 is an explanatory diagram for explaining the electrical connections between the charging roller, the developing roller, the transfer roller, and the peeling roller and the controller. FIG. 3 is a flow chart for explaining the developing method. FIG. 4A is an explanatory diagram for explaining the developing process of FIG. 3. FIG. 4B is an explanatory diagram for explaining the transfer process of FIG. 3. FIG. 5A is an explanatory diagram for explaining the peeling process of FIG. 3. FIG. 5B is an explanatory diagram for explaining the charging process of FIG. 3. FIG. 6A is an explanatory diagram for explaining the exposure process of FIG. 3. FIG. FIG. 6B is an explanatory diagram for explaining the recovery process of FIG. 3 . FIG. 7 shows the timing for applying the charging bias to the charging roller, the timing for applying the developing bias to the developing roller, the timing for applying the transfer bias to the transfer roller, and the timing for applying the peeling roller bias to the peeling roller. is a chart. FIG. 8 is an explanatory diagram for explaining a modification.

1. Outline of Image Forming Apparatus 1 An outline of the image forming apparatus 1 will be described with reference to FIG.

The image forming apparatus 1 includes a main housing 2, a sheet feeding section 3, a photosensitive drum 4, a charging roller 5, an exposure device 6, a housing 7, a developing roller 8, a transfer roller 9, and a fixing device. 10. In this embodiment, the image forming apparatus 1 includes a drum cartridge 11A and a developer cartridge 11B. The drum cartridge 11</b>A includes a photosensitive drum 4 , a charging roller 5 and a transfer roller 9 . The developing cartridge 11B can be attached to the drum cartridge 11A. The developer cartridge 11B includes a housing 7 and a developer roller 8 .

1.1 Main housing 2
The body housing 2 accommodates the sheet feeding section 3 , the photosensitive drum 4 , the charging roller 5 , the exposure device 6 , the housing 7 , the developing roller 8 , the transfer roller 9 , and the fixing device 10 .

1.2 Sheet supply unit 3
The sheet supply section 3 supplies the sheet S to the photosensitive drum 4 . The photosensitive drum 4 will be described later. The sheet supply section 3 includes a sheet cassette 12 , a pickup roller 13 and a conveying roller 14 . The sheet cassette 12 accommodates sheets S. As shown in FIG. The sheet S is, for example, printing paper. The pickup roller 13 picks up the sheet S in the sheet cassette 12 and conveys the picked-up sheet S toward the conveying roller 14 . The conveying roller 14 conveys the sheet S from the pickup roller 13 toward the photosensitive drum 4 .

1.3 Photosensitive drum 4
The photosensitive drum 4 is rotatable about an axis A. As shown in FIG. Axis A extends in a first direction. The photosensitive drum 4 extends along the axis A in the first direction. The photosensitive drum 4 has a cylindrical shape.

1.4 Charging roller 5
The charging roller 5 is positioned on the opposite side of the transfer roller 9 with respect to the photosensitive drum 4 . The charging roller 5 contacts the surface of the photosensitive drum 4 . A negative charging bias is applied to the charging roller 5 . The charging roller 5 to which a negative charging bias is applied negatively charges the surface of the photosensitive drum 4 .

1.5 Exposure device 6
The exposure device 6 forms an electrostatic latent image on the surface of the photosensitive drum 4 by exposing the surface of the photosensitive drum 4 charged by the charging roller 5 .

1.7 Housing 7
The housing 7 can accommodate a non-magnetic one-component negatively charged toner.

1.8 Developing Roller 8
The developing roller 8 can supply the toner in the housing 7 to the surface of the photosensitive drum 4 . The developing roller 8 is supported by the housing 7 . The developing roller 8 contacts the photosensitive drum 4 . A negative developing bias is applied to the developing roller 8 . The developing roller 8 is rotatable about an axis extending in the first direction. A toner image is formed on the surface of the photosensitive drum 4 by supplying the toner in the housing 7 to the surface of the photosensitive drum 4 by the developing roller 8 .

1.9 Transfer roller 9
The transfer roller 9 contacts the photosensitive drum 4 . A positive transfer bias is applied to the transfer roller 9 . A sheet S from the sheet supply section 3 passes between the photosensitive drum 4 and the transfer roller 9 . At this time, the transfer roller 9 can transfer the toner image from the surface of the photosensitive drum 4 to the sheet S by the transfer bias.

1.10 Fixing device 10
The fixing device 10 heats and presses the sheet S onto which the toner image has been transferred, thereby fixing the toner image onto the sheet S. As shown in FIG. The sheet S that has passed through the fixing device 10 is discharged onto the upper surface of the main housing 2 .

2. Details of Image Forming Apparatus Next, details of the image forming apparatus 1 will be described with reference to FIG.

As shown in FIG. 2 , the image forming apparatus 1 further includes a peeling roller 21 , a charging cleaning roller 22 and a control section 23 .

2.1 Peeling roller 21
The peeling roller 21 is provided in the drum cartridge 11A (see FIG. 1). The peeling roller 21 contacts the surface of the photosensitive drum 4 . The peeling roller 21 is rotatable about an axis extending in the first direction. The stripping roller 21 extends along the axis in the first direction. The peeling roller 21 is made of, for example, silicone resin sponge.

2.3 Charged cleaning roller 22
The charged cleaning roller 22 contacts the charged roller 5 . The charged cleaning roller 22 extends in the first direction. The charged cleaning roller 22 is rotatable about an axis extending in the first direction.

The charging cleaning roller 22 follows the charging roller 5 . Therefore, the peripheral speed of the charging roller 5 is substantially the same as the peripheral speed of the photosensitive drum 4 . Preferably, the peripheral speed of the charging roller 5 is the same as the peripheral speed of the photosensitive drum 4 .

A negative cleaning bias having an absolute value equal to or lower than the charging bias is applied to the charging cleaning roller 22 . Residual toner attached to the charging roller 5 is attached from the charging roller 5 to the charging cleaning roller 22 by the cleaning bias. Thereby, the charging cleaning roller 22 cleans the charging roller 5 .

2.4 Control unit 23
The controller 23 comprises, for example, an application specific integrated circuit (ASIC). Note that the control unit 23 may have a central processing unit (CPU). Control unit 23 is electrically connected to charging roller 5 , developing roller 8 , transfer roller 9 and peeling roller 21 . The controller 23 controls charging bias, developing bias, transfer bias and peeling roller bias.

3. Developing Method Next, the developing method will be described with reference to FIGS. 3 to 7. FIG.

As shown in FIG. 3, the developing method includes steps (S1) to (S8).

3.1 Development step (S1)
First, as shown in FIG. 3, the image forming apparatus 1 performs step (S1). In step ( S<b>1 ), the image forming apparatus 1 supplies toner from the housing 7 to the photosensitive drum 4 by the developing roller 8 . Specifically, as shown in FIG. 7, the controller 23 (see FIG. 2) applies a developing bias to the developing roller 8 at time t1. Then, as shown in FIG. 4A, the toner in the housing 7 is supplied by the developing roller 8 to the surface of the photosensitive drum 4 on which the electrostatic latent image is formed, as described above. Thereby, a toner image is formed on the surface of the photosensitive drum 4 .

3.2 Transfer process (S2)
Next, the image forming apparatus 1 performs step (S2) as shown in FIG. The image forming apparatus 1 transfers the toner on the surface of the photosensitive drum 4 to the sheet S with the transfer roller 9 in step (S2). Specifically, as shown in FIG. 7, the controller 23 applies the transfer bias to the transfer roller 9 at time t2 after a predetermined first time T1 has elapsed after applying the development bias to the development roller 8. . The first time T<b>1 is the time until the portion of the surface of the photosensitive drum 4 in contact with the developing roller 8 reaches the transfer roller 9 . Then, as shown in FIG. 4B, the toner on the surface of the photosensitive drum 4 is transferred from the surface of the photosensitive drum 4 to the sheet S by the transfer bias. At this time, part of the toner on the surface of the photosensitive drum 4 remains on the surface of the photosensitive drum 4 without being transferred onto the sheet S. The toner remaining on the surface of the photosensitive drum 4 without being transferred onto the sheet S is the residual toner T. As shown in FIG.

3.3 Step of applying peeling roller bias (S3)
Further, the image forming apparatus 1 executes step (S3) as shown in FIG. The image forming apparatus 1 applies a peeling roller bias to the peeling roller 21 in step (S3). A negative peel roller bias is applied to the peel roller 21 . More specifically, in the step (S3), as shown in FIG. 7, the controller 23 applies the developing bias to the developing roller 8, and after a predetermined first time T1 has elapsed, the peeling roller bias is applied at time t2. is applied to the peeling roller 21 . Note that the step (S3) may be performed simultaneously with the step (S2), or the step (S3) may be performed after the step (S2).

The absolute value of the peel roller bias is smaller than the charging bias and larger than the developing bias. The difference between the absolute value of the peeling roller bias and the absolute value of the charging bias is, for example, 550 V or more and 700 V or less. The difference between the absolute value of the peeling roller bias and the absolute value of the developing bias is, for example, 100 V or more and 250 V or less.

The peeling roller bias is preferably a bias capable of generating electric discharge between the peeling roller 21 and the photosensitive drum 4 . With such a peeling roller bias, the residual toner can be negatively charged more reliably.

3.4 Peeling process (S4)
Next, the image forming apparatus 1 performs step (S4) as shown in FIG. As shown in FIG. 5A, in step (S4), the image forming apparatus 1 removes residual toner from the surface of the photosensitive drum 4 with the peeling roller 21, and negatively removes the residual toner. electrify. Specifically, the peeling roller 21 can peel off the residual toner T from the surface of the photosensitive drum 4 due to the peripheral speed difference between the peeling roller 21 and the photosensitive drum 4 . The peripheral speed of the peeling roller 21 differs from the peripheral speed of the photosensitive drum 4 . Thereby, the peeling roller 21 scrapes the surface of the photosensitive drum 4 . The peeling roller 21 peels off the residual toner T from the surface of the photosensitive drum 4 by rubbing the photosensitive drum 4 .

Then, the peeling roller 21 negatively charges the peeled residual toner T by the peeling roller bias, and attaches the charged residual toner T to the surface of the photosensitive drum 4 . Specifically, the residual toner T stripped from the surface of the photosensitive drum 4 by the stripping roller 21 is negatively charged by the stripping roller bias. The residual toner T charged by the peeling roller 21 adheres to the surface of the photosensitive drum 4 due to the potential difference with the surface of the photosensitive drum 4 .

3.5 Charging step (S5)
Next, the image forming apparatus 1 performs step (S5) as shown in FIG. In step (S5), the image forming apparatus 1 negatively charges the surface of the photosensitive drum 4 with residual toner by the charging roller 5, as shown in FIG. 5B. Specifically, as shown in FIG. 7, the controller 23 applies a negative charging bias to the charging roller 5 at time t3. The absolute value of the charging bias is greater than the absolute value of the peel roller bias. Then, the surface of the photosensitive drum 4 is negatively charged by the charging roller 5 .

3.6 Exposure step (S6)
Next, the image forming apparatus 1 performs step (S6) as shown in FIG. In step (S6), as shown in FIG. 6A, the image forming apparatus 1 charges the photosensitive drum 4 by the charging roller 5 before the toner is supplied to the photosensitive drum 4 by the developing roller 8 by the exposure device 6. expose the surface of Thereby, an electrostatic latent image is formed on the surface of the photosensitive drum 4 .

3.7 Step of applying development bias (S7)
Next, the image forming apparatus 1 performs step (S7) as shown in FIG. The image forming apparatus 1 applies a developing bias to the developing roller 8 in step (S7). More specifically, as shown in FIG. 7, the controller 23 applies the developing bias to the developing roller 8 at time t4 after a predetermined second time T2 has passed after applying the charging bias to the charging roller 5. . The second time T2 is the time it takes for the portion of the surface of the photosensitive drum 4 in contact with the charging roller 5 to reach the developing roller 8 .

3.8 Recovery step (S8)
Next, the image forming apparatus 1 performs step (S8) as shown in FIG. As shown in FIG. 6B, in step (S8), the image forming apparatus 1 recovers residual toner to the housing 7 (see FIG. 1) by the developing roller 8 to which the developing bias is applied.

Note that the step (S8) may be performed simultaneously with the step (S1) in the next printing. Specifically, the developing roller 8 supplies the toner in the housing 7 to the area of the surface of the photosensitive drum 4 where the electrostatic latent image is formed (S1), and The residual toner adhering to the area where the latent image is not formed is collected into the housing 7 (S8). The residual toner remaining on the electrostatic latent image formed area of the surface of the photosensitive drum 4 is used together with the toner supplied from the housing 7 for the next printing.

4. Operation and Effect According to this developing method, as shown in FIG.

As a result, filming on the surface of the photosensitive drum 4 can be suppressed.

Then, the residual toner peeled off from the surface of the photosensitive drum 4 is charged by the peeling roller 21, adhered to the surface of the photosensitive drum 4, and collected into the housing 7 by the developing roller 8 as shown in FIG. 6B. .

Therefore, there is no need to separately provide a container for collecting the residual toner.

In summary, the remaining toner can be collected using the developing roller 8 while suppressing filming on the surface of the photosensitive drum 4 .

5. Modification As shown in FIG. 8, the drum cartridge 11A may include a cleaning roller 30. FIG. Cleaning roller 30 contacts charged cleaning roller 22 . Cleaning roller 30 is rotatable about an axis extending in a first direction. Cleaning roller 30 extends in a first direction along an axis. The cleaning roller 30 has spiral grooves on its peripheral surface. The cleaning roller 30 collects paper dust adhered to the charging cleaning roller 22 .

In this case, the peripheral speed of the charging cleaning roller 22 and the peripheral speed of the charging roller 5 are different. A negative first cleaning bias having a smaller absolute value than the charging bias is applied to the charging cleaning roller 22 . A negative second cleaning bias having a smaller absolute value than the first cleaning bias is applied to the cleaning roller 30 . Cleaning roller 30 is an example of a cleaner member. Note that the cleaner member may be a cleaning blade.

Further, the image forming apparatus 1 may include a toner cartridge that can be attached to the developing cartridge 11B. Specifically, the developer cartridge 11B includes the housing 7 and the developer roller 8 described above. The toner cartridge can be mounted in the housing 7 of the developing cartridge 11B. The toner cartridge accommodates toner supplied to the housing 7 .

Further, the drum cartridge 11A may include the photosensitive drum 4, the charging roller 5, the developing device, and the transfer roller 9. The developing device has a housing 7 and a developing roller 8 . In this case, the image forming apparatus 1 may include a toner cartridge that can be attached to the drum cartridge 11A.

Further, the image forming apparatus 1 may include a cartridge integrally including a drum unit and a developing device. The drum unit includes a photosensitive drum 4 , a charging roller 5 and a transfer roller 9 . The developing device has a housing 7 and a developing roller 8 .

REFERENCE SIGNS LIST 1 image forming apparatus 4 photosensitive drum 5 charging roller 6 exposure device 7 housing 8 developing roller 9 transfer roller 11A drum cartridge 11B developing cartridge 21 peeling roller 22 charging cleaning roller 23 control section 30 cleaning roller S sheet S1 developing process S2 transferring process S3 Step of applying peeling roller bias S4 Peeling step S5 Charging step S6 Exposure step S7 Application of development bias S8 Recovery step T Residual toner T1 First time T2 Second time

Claims (13)

a step of supplying the toner to the photosensitive drum from a housing capable of accommodating non-magnetic one-component negatively charged toner by a developing roller to which a negative developing bias is applied;
transferring the toner on the surface of the photosensitive drum to a sheet by a transfer roller to which a positive transfer bias is applied;
Using a peeling roller to which a negative peeling roller bias having a larger absolute value than the developing bias is applied, the residual toner adhering to the surface of the photosensitive drum is removed by the peripheral speed difference between the peeling roller and the photosensitive drum. removing the residual toner from the surface of the photosensitive drum, negatively charging the peeled residual toner by the peeling roller bias applied to the peeling roller, and applying the charged residual toner to the surface of the photosensitive drum; and,
a step of negatively charging the surface of the photosensitive drum on which the residual toner is attached by a charging roller to which a negative charging bias having a larger absolute value than the peeling roller bias is applied;
and collecting the residual toner into the housing by the developing roller to which the developing bias is applied. 2. The developing method according to claim 1, wherein the residual toner charged by the peeling roller adheres to the surface of the photosensitive drum due to a potential difference with the surface of the photosensitive drum. a step of applying the positive transfer bias to the transfer roller and applying the peeling roller bias to the peeling roller after a predetermined first time has elapsed after applying the developing bias to the developing roller;
and applying the developing bias to the developing roller after a lapse of a predetermined second time after applying the charging bias to the charging roller. The developing method described in . forming an electrostatic latent image on the surface of the photosensitive drum by exposing the surface of the photosensitive drum charged by the charging roller before the toner is supplied to the photosensitive drum by the developing roller; 4. The development method according to any one of claims 1 to 3, further comprising: a housing capable of accommodating a non-magnetic one-component negatively charged toner;
a photosensitive drum on which a toner image made of the toner is formed;
a developing roller to which a negative developing bias is applied and capable of supplying the toner in the housing to the surface of the photosensitive drum;
a transfer roller to which a positive transfer bias is applied and capable of transferring the toner image from the surface of the photosensitive drum to a sheet;
A peeling roller to which a negative peeling roller bias having a larger absolute value than the developing bias is applied, wherein in a state in which the peeling roller bias is applied to the peeling roller, the sheet is not transferred to the sheet and the image is transferred to the photosensitive drum. The peeling roller is capable of peeling residual toner remaining on the surface from the surface of the photosensitive drum by means of a peripheral speed difference between the peeling roller and the photosensitive drum, and the residual toner that has been peeled off is made negative by the peeling roller bias. a peeling roller that is charged and attaches the charged residual toner to the surface of the photosensitive drum;
a charging roller to which a negative charging bias having a larger absolute value than the peeling roller bias is applied, the charging roller negatively charging the surface of the photosensitive drum on which the residual toner is adhered;
An image forming apparatus, wherein the developing roller to which the developing bias is applied collects the residual toner into the housing. The image forming apparatus further comprises a control unit,
The control unit
applying the positive transfer bias to the transfer roller and applying the peeling roller bias to the peeling roller after a lapse of a predetermined first time after applying the developing bias to the developing roller;
6. The image forming apparatus according to claim 5, wherein the developing bias is applied to the developing roller after a predetermined first time has elapsed after the charging bias is applied to the charging roller. An exposure device that forms an electrostatic latent image on the surface of the photosensitive drum by exposing the surface of the photosensitive drum charged by the charging roller before the toner is supplied to the photosensitive drum by the developing roller. 7. The image forming apparatus according to claim 5, further comprising: 8. The image forming apparatus according to claim 5, further comprising a charging cleaning roller for cleaning the charging roller. The charging cleaning roller is driven by the charging roller,
9. The image forming apparatus according to claim 8, wherein a negative cleaning bias having an absolute value equal to or less than said charging bias is applied to said charging cleaning roller. 9. The image forming apparatus according to claim 8, further comprising a cleaner member that contacts the charged cleaning roller and collects paper dust adhered to the charged cleaning roller. Different from the peripheral speed of the charging cleaning roller and the peripheral speed of the charging roller,
a negative first cleaning bias having a smaller absolute value than the charging bias is applied to the charging cleaning roller;
11. The image forming apparatus according to claim 10, wherein a negative second cleaning bias having a smaller absolute value than said first cleaning bias is applied to said cleaner member. The image forming apparatus is
a drum cartridge including the photosensitive drum, the charging roller, and the peeling roller;
12. The image according to any one of claims 5 to 11, further comprising: a developing cartridge mountable to the drum cartridge, the developing cartridge including the casing and the developing roller. forming device. 13. The image forming apparatus according to claim 12, wherein said drum cartridge further comprises said transfer roller.

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