JP2000242145A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently eliminate a filming formed on the surface of a photoreceptor in an image forming device where a recorded image is obtained by having a toner image formed on the surface of the photoreceptor transferred to a transfer paper. SOLUTION: In this image forming device, a standard latent image is formed on the surface of the photoreceptor 1, its surface potential is measured by a surface electrometer 24, when rising of the potential in the photoreceptor surface is detected, the filming is eliminated by having a rotating filming elimination brush 22 made to abut on the surface of the photoreceptor 1, and after its elimination, when a failure in filming elimination is detected, the number of rotation of the filming elimination brush 22 for a next time is made greater.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image carrier on which an electrostatic latent image is formed, a developing device for visualizing the electrostatic latent image as a toner image, and transferring the toner image to a transfer material. The present invention relates to an image forming apparatus having a transfer device that performs transfer and a cleaning device that removes transfer residual toner attached to the surface of an image carrier after transferring a toner image.

[0002]

2. Description of the Related Art In an image forming apparatus of the above type configured as an electronic copying machine, various printers, a facsimile or a multifunction machine having at least two functions thereof,
With the use, the filming substance adheres to the surface of the image carrier in a film form. If such filming is formed on the image carrier, the image quality of the image transferred to the transfer material deteriorates.

For this reason, conventionally, a filming removing brush which is driven to rotate is brought into contact with the surface of the image carrier to remove the filming substance. At that time, conventionally, the number of times of image formation that affects the image due to filming formation is estimated, and each time the number of times is reached, the filming removal brush is brought into contact with the image carrier surface to perform the filming removal operation. ing.

However, the amount of the filming substance adhered to the surface of the image carrier depends on the type of the transfer material to be used, the temperature at the time of using the image forming apparatus, and the number of image forming operations per unit time. Varies depending on conditions. Therefore, if only the filming removing operation is performed every predetermined number of times of image formation as in the related art, a large amount of filming is performed on the surface of the image carrier before the time to perform the filming removing operation. The substance may be fixed, thereby deteriorating the image quality. Conversely, even when it is not necessary to perform the filming removal operation, the operation may be performed to accelerate the deterioration of the surface of the image carrier.

[0005] The effect of the filming removal brush by the filming removal brush varies depending on the degree of adhesion of the filming substance to the image carrier and the degree of deterioration of the filming removal brush such as falling down of the filming brush and hair loss. Therefore, a sufficient filming removing effect cannot be improved only by performing the filming removing operation under the same conditions every time as in the related art. It is conceivable to increase the pressing force of the filming removing brush against the image carrier and the rotation speed of the filming removing brush from the beginning to enhance the filming removing effect. The disadvantage of early deterioration of the body surface is unavoidable.

[0006]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above-mentioned novel recognition, and an object of the present invention is to prevent the image carrier from deteriorating at an early stage and to reduce the filming removal effect. It is an object of the present invention to provide an image forming apparatus of the type described at the beginning, which can enhance the image quality.

[0007]

According to the present invention, in order to achieve the above object, in an image forming apparatus of the type described at the beginning, a potential measurement for measuring a surface potential of a reference latent image formed on the image carrier is provided. Means, and a comparison between the reference latent image potential measured by the potential measuring means and the reference potential, it is determined that the reference latent image potential is a value at which the filming removal operation of the surface of the image carrier should be performed. A filming removal brush that performs a filming removal operation by contacting the image carrier surface while being rotated, and a surface potential of a reference latent image formed on the image carrier surface after the filming removal operation Is measured by the potential measuring means, and as a result of comparing the measured reference latent image potential with the reference potential, the reference latent image potential is still a value at which the filming removal operation of the image carrier surface is to be executed. Control means for controlling the number of rotations of the filming removal brush so that the number of rotations of the filming removal brush at the time of the next filming removal operation is increased when the determination is made. A device is proposed (claim 1).

At this time, it is advantageous to provide a control means for stopping the image forming operation when the number of rotations of the filming removing brush is repeatedly increased and the number of rotations reaches a predetermined maximum number of rotations. Item 2).

The image forming apparatus according to claim 1 or 2, wherein the number of rotations of the filming removing brush is repeatedly increased, and a warning display is displayed when the number of rotations reaches a predetermined maximum number of rotations. It is advantageous to provide a notifying means (claim 3).

In order to achieve the above object, the present invention provides an image forming apparatus of the type described at the beginning, wherein a potential measuring means for measuring a surface potential of a reference latent image formed on the image carrier, As a result of comparing the reference latent image potential measured by the potential measuring means with the reference potential, when it is determined that the reference latent image potential is a value at which the filming removal operation of the surface of the image carrier is to be performed, the rotation driving is performed. A filming removal brush that performs a filming removal operation by contacting the surface of the image carrier while the filming is being performed, and the surface potential of a reference latent image formed on the image carrier surface after the filming removal operation is measured by the potential measurement As a result of comparison between the measured reference latent image potential and the reference potential, it is determined that the reference latent image potential is still a value at which the filming removal operation of the image carrier surface should be performed. Control means for controlling the pressing force of the filming removing brush against the surface of the image carrier so as to increase the pressing force of the filming removing brush against the surface of the image carrier during the next filming removing operation. An image forming apparatus characterized by this is proposed (claim 4).

At this time, there is provided control means for stopping the image forming operation when the pressing force of the filming removing brush against the surface of the image carrier is repeatedly increased and the pressing force reaches a predetermined maximum pressing force. (Claim 5).

Further, in the image forming apparatus according to the fourth or fifth aspect, the pressing force of the filming removing brush against the surface of the image carrier is repeatedly increased, and the pressing force reaches a predetermined maximum pressing force. In such a case, it is advantageous to provide a notification means for displaying a warning (claim 6).

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic view showing an image forming apparatus according to an embodiment of the present invention. First, the overall structure and operation will be briefly described.

In FIG. 1, a belt-shaped photosensitive member 1, which is an example of an image carrier, is wound around a driving roller 2a and another appropriate number of supporting rollers 2, and is rotated in the direction of arrow A by the rotation of the driving roller 2a. Is driven. At this time, the surface of the photoconductor 1 is uniformly charged to a predetermined polarity by the charger 3 constituted by a corona discharger, which is an example of a charging device.
The charged photoreceptor surface is image-exposed by the image forming optical system 4, and a predetermined electrostatic latent image corresponding to a document image (not shown) is formed on the photoreceptor 1. This electrostatic latent image is visualized as a toner image when passing through the developing device 6.

On the other hand, a transfer paper P, which is an example of a transfer material, is fed from the paper feed unit 9 toward the photoconductor 1, and the toner image on the photoconductor 1 is discharged by the discharge action of the transfer device 7 composed of a corona discharger. Is transferred onto the transfer paper. Next, the transfer paper is separated from the photoreceptor 1 while being subjected to the discharging action of a separation device 7a also constituted by a corona discharger, and the separated transfer paper is conveyed to a fixing device 11 by a conveyance belt 10, and this fixing device is 11, the toner image on the transfer paper P is fixed on the transfer paper. The transfer paper that has passed through the fixing device 11 is discharged outside the apparatus, and is stacked on a discharge tray (not shown). After the transfer of the toner image, the transfer residual toner adhering to the photoreceptor surface is cleaned and removed by the cleaning device 8. Thus, the photoconductor 1 is used repeatedly.

The developing device 6 shown in FIG. 1 has an appropriate number of developing sleeves 20, in which a magnet 21 is immovably disposed, and the developing sleeve 20 is driven to rotate. A powdery developer D is carried thereon and transported. As the developer, a two-component developer having a toner and a carrier, or a one-component developer without a carrier is used. The developer D is carried on the developing sleeve 20 and transported. Thus, the electrostatic latent image formed on the photoconductor 1 is visualized as a toner image.

As described above, the image forming apparatus of this embodiment includes the photosensitive member 1 as an example of an image carrier on which an electrostatic latent image is formed,
Developing device 6 for visualizing the electrostatic latent image as a toner image
A transfer device 7 for transferring the toner image onto transfer paper P, which is an example of a transfer material; and a cleaning device 8 for removing transfer residual toner adhering to the surface of the image carrier after transferring the toner image. ing. All such configurations are well known in the art.

During the image forming operation as described above, the filming substance adheres to the surface of the photoreceptor 1. Such filming is caused by fine powder of toner in the developer used in the developing device 6 or when a two-component developer is used.
The fine powder of the carrier adheres to the photoconductor 1, or talc and other chemical components in the transfer paper adhere to the photoconductor 1,
Alternatively, it is considered that nitrogen oxide formed by ozone O ₃ released from the corona discharger adheres to the photoreceptor 1 and is formed. When such filming is formed on the photoreceptor, when the surface of the photoreceptor is exposed by the imaging optical system 4, the surface potential of the photoreceptor hardly attenuates. Decrease. FIG. 2 shows this state. As a result, as shown in FIG. 3, the potential on the photoreceptor after the exposure increases, and the image transferred onto the transfer paper P significantly deteriorates. For ordinary document images,
The background without characters or pictures becomes black, and the image quality deteriorates.

As described above, it is difficult to remove the filming substance fixed on the surface of the photoreceptor by the cleaning device 8 alone. Therefore, in the image forming apparatus shown in FIG. Have been. The filming removing device 5 illustrated here has a filming removing brush 22 composed of a brush roller, and the filming removing brush 22 is a brush (bristles) made of, for example, conductive metal fibers 12 woven into a base cloth. ) And a roller-shaped core material 23 around which the base fabric is wound.

The filming removing brush 22 is connected to the backup roller 1 via the photoreceptor 1 as shown in FIG.
3 and is rotatably supported on the free end side of the arm member 14. The base end of the arm member 14 is the support shaft 1.
5, the arm member 14 is supported so as to be rotatable around the support shaft 15 together with the filming removing brush 22. A cam 16 abuts against the arm member 14, and a shaft 16A of the cam 16 is coaxially connected to an output shaft of a brush press motor 17A as shown in FIG. The operation of the brush pressing motor 17A causes the shaft 16 to rotate.
A rotates together with the cam 16 so that the arm member 1
4 and the filming removal brush 22 can operate between a retracted position shown by a solid line in FIG. 4 and an operation position shown by a chain line. When the filming removal brush 22 is in the operating position, the fiber (brush) 12 contacts the surface of the photoreceptor, and when in the retracted position, it is separated from the surface of the photoreceptor. FIG. 1 shows a state in which the filming removing brush 22 is in an operating position where the brush 22 contacts the surface of the photoconductor 1.

As described above, the filming removal brush 22
Is supported so as to freely contact and separate from the surface of the photoreceptor 1,
The filming removal brush 22 occupies the retracted position. At a time other than when the toner image formed on the photosensitive member surface as described above passes through the filming removing brush 22, the brush pressing motor 17A operates the filming removing brush 22 to move to the operating position, and the photosensitive member surface is moved. Abut. At this time, the filming removing brush 22 is driven to rotate counterclockwise in FIGS. 1 and 4 by a brush driving motor (not shown in FIGS. 1, 4 and 5). The mining is scraped off. The filming substance attached to the fiber (brush) 12 of the filming removal brush 22 is shown in FIG.
Is knocked down by the flicker 18 shown in FIG.
Collected in 9 After the completion of the filming removing operation, the filming removing brush 22 is separated from the surface of the photoreceptor 1 and returned to the retracted position by the operation of the brush pressing motor 17A. Therefore, the toner image formed on the photoconductor 1 is not disturbed by the filming removing brush 22.

As described above, the filming removal brush 22
The filming material on the photoreceptor can be removed by using the toner image formed on the photoreceptor.
It is possible to maintain high quality of the image transferred to the printer. Such a filming removal brush itself is also employed in a conventional image forming apparatus. However, if only the filming removing operation is performed under the same conditions every predetermined number of times of image formation as in the conventional image forming apparatus, a sufficient filming removing effect cannot be obtained, or the filming removing operation cannot be performed. It may be performed excessively and the photoreceptor may be deteriorated early.

Therefore, in the image forming apparatus of this embodiment,
As shown in FIG. 1, a surface electrometer 24, which is an example of a potential measuring unit that measures the surface potential of the photoconductor, is provided at a position upstream of the filming removal brush 22 in the moving direction of the photoconductor surface. 1 is disposed opposite to the surface of the first.
In addition, a reference latent image is formed on the photoreceptor surface, and the surface potential is measured by the surface voltmeter 24, and the reference latent image potential and the reference potential are compared to grasp the filming state of the photoreceptor surface. When it is determined that the filming removal operation is necessary, the filming removal operation is performed on the photoconductor surface by the filming removal brush 22,
Moreover, when it is determined that the filming removing operation does not sufficiently increase in the filming removing operation, the conditions for the next filming removing operation are changed so that a sufficient filming removing effect can be obtained. ing.

In a copying machine or the like using an analog optical device as in the image forming apparatus shown in FIG.
Is uniformly charged by the charger 3, and then a non-image area other than an area where a toner image is formed on the photoreceptor, for example, a blank paper or a white-painted high-reflectance member (not shown) And the reflected light is applied to the charged surface of the photoreceptor 1 to form the above-described reference latent image. In an image forming apparatus using a digital optical device, the surface of the photoreceptor is uniformly charged, and the charged surface is irradiated with light from a laser or an LED or the like of an optical writing unit to a predetermined area on a non-image area on the photoreceptor. A latent image in the form of a pattern having a size can be formed and used as a reference latent image.

FIG. 6 shows an example of a control block diagram including the surface voltmeter 24. In this example, a ROM 26 in which an execution program is written, a potential data of a reference latent image and the like, a RAM 27 in which data is held by a battery (not shown), and an analog signal A / D converter 28 to replace I / O interface I
The / O port 29 is connected by a parallel bus line. The measured potential (analog value) of the surface voltmeter 24 is T
The voltage is converted to a voltage of about the TL signal level and input to the A / D converter 28.

On the other hand, the I / O port 29 includes a drive unit 30 composed of a photoreceptor motor 30A for driving the photoreceptor 1 and a driver 30B, the aforementioned brush drive motor 31A for driving the filming removing brush 22 and the driver 31
The drive unit 31 made of B, the brush press motor 17A for pressing the filming removal brush 22 against the surface of the photoreceptor, and the drive unit 17 made up of the driver 17B are output connected.

The display device 32, which is an example of the notifying means, has a CP
U25, this display device 32 is, for example, LED
Alternatively, it is configured as a display device using liquid crystal. As for the connection method, the display data is transmitted by a parallel bus or a serial connection using a serial communication element (not shown) as in the ROM 26 or the like.

FIGS. 7 and 8 are flowcharts showing an operation example of the image forming apparatus including the filming removing operation. First, the reference potential (initial potential) V0 of the aforementioned reference latent image
Is set in the program. When the above-described image formation is started (S1 in FIG. 7), a reference latent image is formed in a non-image area on the photoreceptor (S2 in FIG. 7), and the surface of the reference latent image is measured by the surface voltmeter 24. Measure the potential V1 (FIG. 7)
S3). Next, the difference (V1−V0) between the measured reference latent image potential V1 and the reference potential V0 is larger than a predetermined value a (a> 0) or the predetermined value a.
It is determined whether it is the following (S4 in FIG. 7). (V1-V
When the value of 0) is equal to or less than the predetermined value a, no filming is formed on the surface of the photoconductor, or even if filming is formed on the surface of the photoconductor,
This does not adversely affect the image. Therefore, in this case, it is checked whether or not there is a job remaining (S5 in FIG. 7). If there is no job remaining, all the operations are terminated (S16 in FIG. 8). If there is a job remaining, the image forming operation is continued and the above-described operation is repeated.

Here, "image formation" in S1 of FIG.
Means one image forming operation of forming a toner image on the surface of the photoconductor 1 and transferring the toner image to the transfer paper P. Therefore, in the examples of FIGS. 7 and 8, the formation of the reference latent image is performed. When,
The measurement and the determination of (V1-V0)> a are performed for each image formation. On the other hand, a job refers to a series of image forming operations. In the case where N image forming operations are performed, a toner image is transferred to each of N transfer sheets, and all the transfer sheets are discharged to a discharge tray. At this time, one job is completed.

In S4 of FIG. 7, (V1-V0)> a
When it is determined that the surface potential of the reference latent image increases due to the formation of filming on the surface of the photoreceptor, and if the image forming operation is continued as it is, the image quality will be deteriorated soon or immediately. After the completion of the job, the photoconductor motor 30A is rotated to drive the photoconductor 1, and the filming removal brush 22 is brought into contact with the surface of the photoconductor 1 as described above. The filming removing brush 22 is rotated by 31A to execute the filming removing operation (S6, S7 in FIG. 7).
This filming removal operation is continued until the photoconductor 1 makes a predetermined number of rounds, in this example, one round (S8 in FIG. 7). When the photoreceptor makes one rotation, the filming removal operation has been performed for the entire circumference of the photoreceptor. Thereafter, the filming removal brush 22 is separated from the surface of the photoreceptor to stop its rotation, and the filming removal operation is performed. To end.

If it is checked in step S6 that there is a job remaining, it is determined whether the job remains in a large amount (for example, 1000 or more times of image formation) (S9 in FIG. 7). When there is a large amount of filming, if the filming removal operation is performed after all of these operations are completed, filming may be formed on the surface of the photoreceptor during that time, which may adversely affect the image. (S7, S8 in FIG. 7). When the number of remaining jobs is small, for example, when the number of remaining image formations is less than 1000, the remaining jobs are continuously performed (FIG. 7).
S10), and after the end of the job, the filming removing operation is executed (S6, S7, S8 in FIG. 7). The remaining value of the job is ended by setting the value of the predetermined value a to a small value and performing the filming removing operation before the filming formed on the photoconductor surface actually affects the image. Even if the filming removing operation is performed after that, no problem occurs.

As described above, when the difference between the reference potential V1 and the reference potential V0 measured by the surface voltmeter 24 is larger than the predetermined value a, the reference potential of the reference latent image is removed from the surface of the photosensitive member. It is determined that the value is a value at which the operation is to be executed, and the filming removing brush 22 is brought into contact with the surface of the photoreceptor while being rotationally driven to execute the filming removing operation. As a result of comparing the measured reference latent image potential V1 and the reference potential V0, when it is determined that the reference latent image potential should perform the filming removal operation on the photoconductor surface, filming of the photoconductor is performed. The removal operation is performed.

As described above, the image forming apparatus of this embodiment is a surface voltmeter 2 which is an example of a potential measuring means for measuring the surface potential of a reference latent image formed on a photosensitive member 1 which is an example of an image carrier.
4 and a comparison between the reference latent image potential V1 and the reference potential V0 measured by the potential measuring means, the result is that the reference latent image potential is a value at which the filming removal operation of the image carrier surface is to be executed. And a filming removing brush 22 that performs a filming removing operation by being in contact with the surface of the image carrier while being rotationally driven when the determination is made.

According to this configuration, since the filming shape of the photoreceptor surface is determined and the removal operation is performed, the filming can be removed at an appropriate time and the occurrence of image deterioration due to the filming can be effectively prevented. In addition, it is possible to effectively suppress the problem of deteriorating the surface of the photoconductor by performing the filming removing operation when unnecessary.

However, the effect of the filming removing brush 22 by the filming removing brush 22 is such that the filming substance adheres to the surface of the photoreceptor, and the filming removing brush 2 such as the falling down of the filming brush 22 or the hair loss.
Therefore, if the filming removing operation is always performed under the same condition, a sufficient filming removing effect cannot be obtained.

Therefore, in the image forming apparatus of this embodiment,
The filming removal operation is performed in S7 and S8 in FIG. 7, and the reference latent image is formed again on the photoreceptor surface after the filming removal operation as described above, and the surface potential V2 is set to the surface potential. It is measured by the electrometer 24 (S in FIG. 7).
11), it is determined whether or not the difference (V2-V0) between the reference potential V2 and the reference potential V0 is greater than a predetermined value a (S12 in FIG. 8). Here, when the value of (V2−V0) is equal to or smaller than the predetermined value a, it is determined that the effect of the filming removal operation in S7 of FIG. 7 has been sufficiently obtained, and the remaining job is confirmed (see FIG. 8). S14) When there is a remaining job, the job is continued (S15 in FIG. 8), and when there is no remaining job, all operations are terminated (S16 in FIG. 8).

In S12 of FIG. 8, (V2-V0)>
When it is checked that the value is a, the effect of the filming removal operation in S7 is not sufficiently increased due to the degree of fixation of the filming material on the photoreceptor surface or the deterioration of the filming removal brush 22. Thus, the rotation speed of the filming removal brush 22 is controlled such that the rotation speed of the filming removal brush 22 in the next filming removal operation is increased (S13 in FIG. 8). That is, when the rotation speed of the filming removal brush 22 at the time of the previous filming removal operation is r _n−1 , the rotation speed of the filming removal brush 22 at the next filming removal operation is increased by Δr, and r _n-1 + _Δr = and r _n.
By doing so, the filming removing effect is enhanced in the next filming removing operation, and the filming can be removed effectively. If the number of rotations of the filming removal brush is increased from the beginning, filming removal can be performed more efficiently than at the beginning. However, such a method involves a problem that the surface of the photoconductor is deteriorated early. In the image forming apparatus of this example, such a problem can be avoided. It should be noted that the rotation speed of the filming removal brush in this specification indicates the rotation speed per unit time.

After the number of rotations of the next filming removal brush is changed as described above, the presence or absence of a remaining job is confirmed, and the process ends (S14, S15, S16 in FIG. 8).

In the above specific example, both the predetermined value in S12 of FIG. 8 and the predetermined value in S4 of FIG. 7 have the same value a, but they may be different values. In short, the surface potential of the reference latent image formed on the photoreceptor surface after the filming removal operation was measured by the surface voltmeter 24, and the measured reference latent image potential V2 was compared with the reference potential V0. As a result, the reference latent image potential V2
Alternatively, when it is immediately determined that the filming removal operation should be performed on the photoconductor surface, the rotation speed of the filming removal brush 22 in the next filming removal operation may be increased.

As described above, the image forming apparatus according to the present embodiment measures the surface potential of the reference latent image formed on the surface of the image carrier comprising the photosensitive member 1 after the filming removal operation by using a surface voltmeter. 24, and as a result of comparing the measured reference latent image potential V2 with the reference potential V0, the reference latent image potential V2 still performs the filming removal operation on the surface of the image carrier. Control means is provided for controlling the number of revolutions of the filming removing brush 22 so that when it is determined that the value is a power value, the number of revolutions of the filming removing brush 22 in the next filming removing operation is increased. I have.

In the example shown, the CPU 2 shown in FIG.
5, the ROM 26, the RAM 27, the I / O port 29, the drive unit 31, and the like constitute the above-described control means. At this time, as a specific method of controlling the number of rotations of the filming removing brush 22, an open loop control using a pulse motor as the brush driving motor 31A or a rotation amount is detected by an encoder coaxial with the motor shaft, and a motor driving driver is used. There is a control to feed back to. A method using a pulse motor will be described. The rotation speed of the pulse motor is determined by the number of input pulses (pulse frequency) per unit time. Assuming that the input pulse frequency is f, the rotation speed r of the filming removal brush 22 at that time is (r = f × step angle of pulse motor / 360). Therefore, in order to control the rotation speed of the filming removal brush 22, the pulse frequency is controlled. The initial value of the input pulse frequency is f
If the value is set to 0, the initial value is written in the ROM 26, and this value is output to the I / O port 29 and input to the brush driving motor driver 31B in the initial operation of the filming removal brush 22. At this time, filming removal brush 2
2 rotates at the initial rotation speed r0. As described above, the number of rotations of the filming removal brush 22 can be increased by increasing the input pulse frequency.

If the above configuration is referred to as a first specific example, in the image forming apparatus of the first specific example,
The rotation speed of the filming removal brush 22 is controlled to increase several times. However, when the rotation speed reaches a certain limit value, the filming removal brush 22 is deteriorated, and the filming removal efficiency is reduced. . If the filming removal brush 22 is rotated at a high speed in such a state, the deterioration of the photoconductor surface may be accelerated. Such a filming removing brush 22 should be replaced with a new one.

Therefore, in the second and third examples, the structure shown in FIG. 9 is employed instead of the structure shown in FIG. 8 in the first example. That is, also in FIG. 9, (V2-V0)> a in S12.
Is checked. If (V2-V0) is equal to or less than a, the remaining job is confirmed and all operations are terminated (S14, S15, S16 in FIG. 9), and (V2-V0)
If V0)> a, the next rotation of the filming removal brush 22 is controlled so as to be added (S in FIG. 9).
13).

[0045] Here, overwriting the rotational speed r _n of filming removing brush 22 when increasing the rotational speed as speed data on the RAM 27 (FIG. 6). On the other hand, the rotational speed of the upper limit of the filming removing brush 22, i.e. the maximum rotational speed r _max is provided, each time the writing to the RAM27 as described above, and compares the rotational speed r _n and the maximum rotational speed r _max ( S17 in FIG. 9). Then, when the rotation speed r _n has reached the maximum rotational speed r _max max, more even by increasing the rotational speed of the filming removing brush 22 can not be removed filming on the photosensitive member, breaking the surface of the photosensitive member It is determined that there is a risk of causing the image forming operation to stop, and the image forming operation is stopped (S18 in FIG. 9).
A warning is displayed on the display device (display unit) 32 shown in FIG. 6 (S19 in FIG. 9), and all operations are ended (S1 in FIG. 9).
6). The warning display on the display device 32 is, for example, a display for replacing the filming removal brush 22, or a display for replacing the photoconductor 1 in some cases. The warning display may be stopped, and only the image forming operation may be stopped, or only the warning display may be performed. Other configurations of the second and third specific examples are the same as the configurations of the first specific example shown in FIGS. 1 to 7.

[0046] As described above, in the image forming apparatus of the second embodiment, in addition to the configuration of the first example described above, repeated rotation speed increase in filming removing brush 22, whose rotational speed r _n Control means for stopping the image forming operation when a predetermined maximum number of revolutions r _max is reached is provided. In the illustrated example, the CPU 25 and the RAM shown in FIG.
27 and the like constitute the control means.

[0047] In the third embodiment, in addition to the configuration of the first or second embodiment described above, repeated rotation speed increase in filming removing brush 22, the rotational speed r _n is predetermined When the maximum rotation speed _rmax is reached, a notification means for displaying a warning is provided.
The U25 and the display device 32 constitute the notification means.

According to the second or third embodiment, the upper limit of the number of revolutions of the filming removing brush 22 is provided, so that the limit of the filming removing ability of the filming removing brush 22 is known. When this happens, replacement of the filming removal brush 22 is encouraged, and high filming removal efficiency can always be maintained.

FIG. 10 shows a fourth specific example. FIG.
In the first specific example shown in FIGS.
0)> a is detected and when it is determined that the filming removal effect of the filming removal brush 22 is insufficient, the rotation speed of the next filming removal brush 22 is increased. The pressing force of the brush 22 against the photoconductor 1 is also proportional to the filming removal ability.
In the specific example, instead of increasing the rotation speed of the filming removing brush 22, the pressure of the filming removing brush 22 against the photoreceptor 1 is increased.

Assuming that the pressing force of the filming removing brush 22 in contact with the photoreceptor 1 during the previous filming operation is X _n−1 , (V2−V0)> a is determined in S12 of FIG. When it is determined that the filming removal effect is insufficient with the force X _n−1 , the pressing force of the filming removal brush 22 to the photoconductor 1 at the next filming removal operation is increased by ΔX. The pressing force is set to _Xn (S20 in FIG. 10). When the pressing force of the filming removing brush 22 is increased in this manner, the contact area between the filming removing brush 22 and the photoconductor 1 increases, and the bristles (brush) of the filming removing brush 22 become filmed due to the elasticity of the bristles. The ability to bite and scrape up. In this case, too, the pressing force of the filming removal brush 22 against the photoreceptor 1 is not increased from the beginning, but is increased little by little, so that the load on the photoreceptor is increased, and the filming removal brush 22 and the photoreceptor are quickly mounted. Deterioration can be prevented.

The above-described two methods can be considered as a method of controlling the pressing force. Here, an example in which a stepping motor is used as the brush pressing motor 17A shown in FIG. 5 will be described. Is determined by the number of input pulses. Assuming that the number of input pulses is p, the rotation amount R of the motor shaft at that time is R = p × step angle of pulse motor / 360. Therefore, in order to control the rotation amount of the motor 17A, the number of input pulses is controlled, and the initial value of the number of input pulses is set to p0. The initial value is written in the ROM 26 (FIG. 6), and this value is output to the I / O port 29 at the beginning of the filming removal operation.
It is input to the driver 17B of the brush pressure motor 17A.
By increasing the number of pulses, the pressing force of the filming removal brush 22 against the photoconductor 1 increases by ΔX.
By increasing the number of input pulses in this manner, the pressing force of the filming removal brush 22 against the photoconductor 1 can be increased stepwise. Other configurations of the fourth specific example shown in FIG. 10 are the same as those of the first specific example shown in FIGS.

As described above, in the image forming apparatus of the fourth embodiment, instead of the control means of the first embodiment, the image forming apparatus is formed on the surface of the image carrier after the filming removal operation. The surface potential of the reference latent image is measured by a potential measuring means, and as a result of comparison between the measured reference latent image potential and the reference potential, the reference latent image potential is still used for filming removal operation on the surface of the image carrier. When it is determined that the value is a value to be executed, the pressure of the filming removing brush against the surface of the image carrier is increased so that the pressure of the filming removing brush against the surface of the image carrier during the next filming removing operation is increased. Control means for controlling the force is provided, and in the illustrated example, the CPU 25, the ROM 26, and the R
The AM 27, the I / O port 29, the drive unit 17, and the like constitute the control means.

FIG. 11 shows fifth and sixth specific examples. In this example, the configuration shown in FIG. 11 is employed instead of the configuration shown in FIG. 10, and in S20, the pressing force of the filming removing brush 22 against the photoconductor 1 at the next filming removing operation increases to _Xn . Then, the pressing force _Xn is overwritten as the pressure increase data on the RAM 27 (FIG. 6). Further, the maximum pressing force X _max which is the upper limit of the pressing force is set in advance, each time the writing to the RAM 27, and the pressing force X _n and the maximum pressure force X _max is compared (S21 in FIG. 11). The pressing force X _n is the maximum pressing force X
_{When the maximum value} has been reached, it is determined that even if the pressing force is further increased, the filming removing effect is not improved, and only the photoconductor load is increased, and the image forming operation is stopped (S in FIG. 11).
18), a warning is displayed on the display device (display unit) 32 shown in FIG. 6 (S19 in FIG. 11), and all the operations are terminated (S16 in FIG. 11). The display in this case is, for example, a display urging replacement of the filming removal brush 22 or the photoconductor 1 with the brush 22. If the pressing force _Xn does not reach the maximum pressing force _Xmax , the remaining job is confirmed and all operations are terminated (S14, S15, S16 in FIG. 11). Another configuration is shown in FIG.
There is no difference from the fourth specific example shown in FIG.

As described above, in the image forming apparatus according to the fifth embodiment, in addition to the configuration of the fourth embodiment, the press-contact force of the filming removing brush against the surface of the image carrier made of the photosensitive member 1 is repeatedly increased. When the pressing force _Xn reaches a predetermined maximum pressing force _Xmax , control means for stopping the image forming operation is provided. In the illustrated example, the CPU 25 shown in FIG. Make up.

In the sixth embodiment, in addition to the configuration of the fourth or fifth embodiment, the pressing force of the filming removing brush against the surface of the image carrier is repeatedly increased, and the pressing force X _{n is obtained.} When a predetermined maximum pressing force _Xmax is reached, a notifying means for displaying a warning is provided. In the illustrated example, the CPU 25 and the display device 32 shown in FIG. 6 constitute the notifying means.

According to the fifth or sixth specific example, the upper limit of the pressing force of the filming removing brush 22 against the photosensitive member 1 is provided, so that the limit of the filming removing ability of the filming removing brush 22 is known. When the limit is reached, replacement of the filming removal brush 22 is encouraged, and a high filming removal efficiency can be always maintained.

In each of the specific examples described above, the surface potential of the reference latent image was measured every time an image was formed. In particular, when the number of times of image formation of one job is small, the job is terminated. Immediately after that, the surface potential of the reference latent image may be measured. Further, for example, when the image forming apparatus is operated only in the daytime and its main switch is turned off at night, and when the number of image formations per day is small, only when the main switch of the image forming apparatus is turned on, It may be configured to measure the surface potential of the reference latent image.

The present invention can be widely applied to image forming apparatuses of various forms other than the form shown in FIG.

[0059]

According to the first aspect of the present invention, if there is a defective removal after the filming removing operation, the rotation speed of the filming removing brush is increased at the next filming removing operation. It is possible to reliably perform the trimming removing operation and to always form a stable and high-quality image.

According to the second aspect of the present invention, since the upper limit of the number of rotations of the filming removing brush is provided, the limit of the filming removing ability of the filming removing brush is known.
When the limit is reached, the image forming operation is stopped to prevent the formation of an image of poor quality.

According to the third aspect of the present invention, since the upper limit of the number of rotations of the filming removing brush is set, the limit of the filming removing ability of the filming removing brush is known.
When the limit is reached, a warning message is displayed, and replacement of the filming removal brush can be prompted.

According to the fourth aspect of the present invention, if there is a defective removal after the filming removing operation, the pressing force of the filming removing brush against the image carrier is increased at the next filming removing operation. In addition, it is possible to reliably perform the filming removing operation and to always form a stable and high-quality image.

According to the fifth aspect of the present invention, since the upper limit of the pressing force of the filming removing brush is set, the limit of the filming removing ability of the filming removing brush is known.
When the limit is reached, the image forming operation is stopped to prevent the formation of an image of poor quality.

According to the sixth aspect of the invention, since the upper limit of the pressing force of the filming removing brush is set, the limit of the filming removing ability of the filming removing brush is known.
When the limit is reached, a warning message is displayed, and replacement of the filming removal brush can be prompted.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view illustrating an example of an image forming apparatus.

FIG. 2 is a graph showing a relationship between a filming lamination amount and a surface potential attenuation amount of a photoconductor.

FIG. 3 is a graph showing the relationship between the filming lamination amount and the surface potential of a photoconductor.

FIG. 4 is an explanatory diagram showing a retracted position and an operating position of the filming removing brush.

FIG. 5 is a perspective view of a cam and a brush pressure motor that drives the cam.

FIG. 6 is a control block diagram of the image forming apparatus shown in FIG.

FIG. 7 is a flowchart relating to a filming removing operation of the image forming apparatus shown in FIG. 1;

FIG. 8 is a flowchart relating to a filming removing operation of the image forming apparatus shown in FIG. 1;

FIG. 9 is a flowchart of another example.

FIG. 10 is a flowchart of still another example.

FIG. 11 is a flowchart of still another example.

[Explanation of symbols]

 Reference Signs List 6 developing device 7 transfer device 8 cleaning device 22 filming removal brush

Claims (6)

[Claims] An image carrier on which an electrostatic latent image is formed; a developing device for visualizing the electrostatic latent image as a toner image; a transfer device for transferring the toner image to a transfer material; An image forming apparatus having a cleaning device for removing transfer residual toner adhered to the surface of an image carrier after transferring an image, wherein a potential measuring unit for measuring a surface potential of a reference latent image formed on the image carrier; As a result of the comparison between the reference latent image potential and the reference potential measured by the potential measuring means, when it is determined that the reference latent image potential is a value at which the filming removal operation of the image carrier surface should be performed, A filming removal brush that performs a filming removal operation by being in contact with the image carrier surface while being driven to rotate, and a surface potential of a reference latent image formed on the image carrier surface after the filming removal operation is performed. Potential measurement means From the measured reference latent image potential and the reference potential, when it is determined that the reference latent image potential is still a value at which the filming removal operation of the surface of the image carrier should be performed. An image forming apparatus provided with control means for controlling the number of rotations of the filming removing brush so as to increase the number of rotations of the filming removing brush at the time of the next filming removing operation. 2. The image forming apparatus according to claim 1, further comprising a control unit for stopping the image forming operation when the number of rotations of the filming removing brush is repeatedly increased and the number of rotations reaches a predetermined maximum number of rotations. Image forming device. 3. A notifying means according to claim 1, further comprising a warning means for displaying a warning when the number of rotations of the filming removing brush is repeatedly increased and the number of rotations reaches a predetermined maximum number of rotations. Image forming device. 4. An image carrier on which an electrostatic latent image is formed, a developing device for visualizing the electrostatic latent image as a toner image, a transfer device for transferring the toner image to a transfer material, and a toner An image forming apparatus having a cleaning device for removing transfer residual toner adhered to the surface of an image carrier after transferring an image, wherein a potential measuring unit for measuring a surface potential of a reference latent image formed on the image carrier; As a result of the comparison between the reference latent image potential and the reference potential measured by the potential measuring means, when it is determined that the reference latent image potential is a value at which the filming removal operation of the image carrier surface should be performed, A filming removal brush that performs a filming removal operation by being in contact with the image carrier surface while being driven to rotate, and a surface potential of a reference latent image formed on the image carrier surface after the filming removal operation is performed. Potential measurement means From the measured reference latent image potential and the reference potential, when it is determined that the reference latent image potential is still a value at which the filming removal operation of the surface of the image carrier should be performed. And control means for controlling the pressing force of the filming removing brush against the image carrier surface so that the pressing force of the filming removing brush against the image carrier surface at the time of the next filming removing operation is increased. An image forming apparatus comprising: 5. A control means for stopping the image forming operation when the pressing force of the filming removing brush repeatedly increases against the surface of the image carrier and the pressing force reaches a predetermined maximum pressing force. The image forming apparatus according to claim 4. 6. A notifying means for displaying a warning when the pressing force of the filming removal brush against the surface of the image carrier is repeatedly increased and the pressing force reaches a predetermined maximum pressing force. 6. The image forming apparatus according to 4 or 5.