JP2892063B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a latent image carrier on which a toner image is formed at the time of image formation, and an agent which is opposed to the carrier and which carries an agent by magnetic force. The present invention relates to an image forming apparatus having an agent carrier for conveying an agent while forming a magnetic brush, and a regulating unit for regulating an amount of the agent conveyed to a region between the latent image carrier and the agent carrier. .

[Conventional technology]

Conventionally, an image forming apparatus that forms an electrostatic latent image on a latent image carrier, visualizes the latent image with toner, transfers the toner image to a transfer material, and repeatedly uses the latent image carrier has been conventionally used. It is well known. Such an image forming apparatus is configured as, for example, an electronic copying machine, a printer, a facsimile, or the like.

By the way, in this type of image forming apparatus, there is a possibility that a so-called filming phenomenon occurs in which toner, paper dust, additives contained in paper, etc. adhere to the surface of the latent image carrier in a thin film. When such a phenomenon occurs, a partial increase in the density of the toner image and background contamination occur, and the image quality of the toner image is significantly reduced.

Therefore, various methods for removing filming on the latent image carrier have been conventionally proposed.Filming is removed while polishing the surface of the latent image carrier with an abrasive or a polishing brush.
A typical example is a method in which a blade is pressed against a latent image carrier to remove filming (for example, see
JP-A-62-119567, JP-A-60-107076, JP-A-60-107
-119589).

However, according to the above-described configuration, a special member for removing filming such as a polishing brush is required, so that there is a problem that the cost is increased, and the brush or the blade causes the latent image carrier to wear out at an early stage. There is a risk of generating an abnormal image in the shape of a letter or shortening the life of the latent image carrier.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus of the type described at the beginning, which can effectively remove filming of a latent image carrier without causing the above-mentioned problems.

[Means for solving the problem]

The present invention, in order to achieve the above object, in an image forming apparatus of the type described at the beginning, at the time of filming removal operation other than at the time of image formation to form a toner image on a latent image carrier,
An image forming apparatus comprising: control means for controlling the transport and stop of the agent so that the transport of the agent and the transport operation of the agent are repeated at least once each while the latent image carrier is being operated. A device is proposed (claim 1).

In order to achieve the same object, the present invention provides an image forming apparatus of the type described at the beginning, in which a toner image is formed on a latent image carrier during a filming removing operation other than when forming a toner image on the latent image carrier. Detects the rotation speed of at least one of the agent carrier and the latent image carrier with the amount of the agent capable of scraping off the filming conveyed to the area between the latent image carrier and the agent carrier. Detecting means for detecting the rotation of at least one of the agent carrier and the latent image carrier having become zero or a predetermined value or less during the filming removing operation. The present invention proposes an image forming apparatus comprising control means for controlling the amount of the agent to be conveyed so that the amount of the agent conveyed decreases.

Further, in the image forming apparatus according to claim 1 or 2, the control means for setting the execution time of the filming removing operation to be longer as the image forming operation time before executing the operation is longer. It is advantageous to provide (claim 3).

Further, in the image forming apparatus according to any one of claims 1 to 3, when an image forming command is input while performing the filming removing operation for a predetermined time after the image forming operation is completed. It is advantageous to include a control means for interrupting the filming removal operation, giving priority to image formation, and adding a shortage of the filming removal operation to execute the filming removal operation after completion of the image formation. (Claim 4).

Further, in the image forming apparatus according to any one of claims 1 to 4, the agent on the carrier is conveyed by rotating the agent carrier, and the linear velocity of the agent carrier is set to a value of v _s latent. when the linear velocity of the image carrier and v _p, when conveying the amount of agent that can be scraped off filming during filming removal operation is _{0 <| v s / v p} | < so as to satisfy 0.5 It is advantageous to have control means for setting v _s and v _p (claim 5).

Furthermore, in the image forming apparatus according to any one of the first to fifth aspects, it is advantageous to include a control unit that makes the linear speed of the latent image carrier faster during the filming removing operation than during the image forming operation. (Claim 6).

〔Example〕

Hereinafter, embodiments of the present invention will be described. FIG. 1 shows a color copying machine as an example of an image forming apparatus. First, the overall configuration will be clarified for understanding the present invention.

In this copying machine, first, illumination scanning is performed on a document (not shown) placed on the contact glass 10 by moving the illumination device 11 to the right along with the first mirror 12 in the drawing. At this time, the scanning light image is transmitted through the second mirror 13 and the third mirror 14 moving in the same direction to the lens 15.
And then passes through a fourth mirror 16 and a filter device 17 to form a drum-shaped photoreceptor which is an example of a latent image carrier.
The image is projected on 18. The filter device 17 has a plurality of color separation filters, and these filters can be rotated by 90 ° so that the filters can be freely selected and used. Then, one of these filters first extracts a light image of, for example, a blue component, and this light image is image-formed and projected on a photoreceptor 18 already uniformly charged by a charger 19. Thus, an electrostatic latent image is formed on the photoconductor.

A yellow developing device 21Y, a magenta developing device 21M, and a cyan developing device 21C are provided below the photoreceptor 18, respectively. The electrostatic latent image is first formed into a toner image by a yellow toner of the yellow developing device 21Y.

A transfer paper, which is an example of a transfer material sent from the paper supply unit 23, is wound and held on the transfer drum 22, and the toner image is transferred onto the wound transfer paper by the transfer charger 20.

Similarly, by using the other filters, the magenta magenta toner image and the cyan cyan toner image formed on the photoreceptor are respectively transferred to and superimposed on the transfer paper. When a black toner image is obtained, the electrostatic latent image is visualized by the black toner of the black developing device 21B. In the case of black exposure, ND is used as a filter.
In some cases, a filter is used or such a filter is not used.

In FIG. 1, reference numerals 50Y, 50M, 50C, and 50B denote developing sleeves of the respective developing devices, each of which is driven to rotate in the direction of an arrow, carries a developer on its peripheral surface, and conveys the photosensitive material.
Each electrostatic latent image on 18 is sequentially formed into a toner image.

After the transfer of the toner image, the transfer paper is separated from the transfer drum 22 by the separation charger 24 and the separation claw 25, and the separated transfer paper is discharged outside the machine as a copy paper through the fixing device 26. On the other hand, the toner remaining on the photoreceptor 18 after the transfer of the toner image of each color is removed by the magnetic brush cleaning device 27 each time.

FIG. 2 shows the details of the magnetic brush cleaning device 27.

The photoreceptor 18 rotates in the direction of the arrow.
A pre-cleaning charger 28 is provided on the downstream side of the transfer section, which is a contact section between the photoconductor 18 and the transfer drum 22, so as to face the photoconductor 18. Further, a plurality of magnets 31 were provided inside on the downstream side of the pre-cleaning charger 28,
For example, a cleaning sleeve 32 made of a conductive non-magnetic material such as aluminum is provided. For each magnet
P ₁ to are denoted by the sign of P _6, the magnetic poles on the side facing the cleaning sleeve 32 of each magnet has a different polarity alternately. The cleaning sleeve 32 is an example of a configuration of the agent carrier. In this embodiment, the sleeve 32 is moved in a direction indicated by an arrow (clockwise) with respect to the fixed magnet 31 by a drive motor not shown in FIG. ). Reference numeral 40 denotes a cleaning case of the cleaning device 27. The side of the case 40 facing the photoreceptor 18 is open, and a part of the cleaning sleeve 32 is exposed at the opening. It faces 18.

After the transfer of the toner image, when the toner remaining on the photoreceptor 18 comes to the pre-cleaning charger 28,
Due to the corona discharge by the pre-cleaning charger 28, a charge of a certain polarity (positive in the example in the drawing) is given to the toner particles so as to facilitate cleaning.

On the other hand, on the peripheral surface of the cleaning sleeve 32, a cleaning agent C composed of a magnetic carrier for cleaning and toner is carried by the magnetic force of the magnet 31, and a magnetic brush is formed by the carrier. More specifically,
The cleaning agent C is composed of powder of a carrier and a toner that are frictionally charged to different polarities, and particles of a carrier made of a magnetic material are carried on the sleeve 32 by magnetic force, and the toner is electrostatically attached to the particles. I have. It is well known that toner includes only toner particles and toner to which an additive is added. The cleaning agent C is conveyed in the rotation direction of the cleaning sleeve 32 by the rotation of the cleaning sleeve 32, and rubs in the cleaning area X on the surface of the photoconductor 18 located opposite to the cleaning sleeve 32.

When the residual toner charged by the pre-cleaning charger 28 comes to the cleaning area X facing the cleaning sleeve 32, the residual toner is applied with a bias voltage (negative in the example of FIG. 1) by the power supply 41. It adheres to the cleaning carrier having a negative charge on the cleaning sleeve 32 with an electrostatic attraction force and a mechanical scavenging force. Thus, the toner on the photoreceptor 18 is removed and cleaning is performed.

Next, the carrier to which the toner has adhered is carried on the cleaning sleeve 32 by magnetic force and is conveyed while forming a magnetic brush. For example, a bias voltage having a predetermined polarity (negative in the example in the drawing) made of metal is applied to the power supply. At a portion facing the toner collecting roller 33 applied by the roller 42, the toner comes into contact with the roller 33, and at this time, the toner is electrostatically attached to the collecting roller 33. At that time, a certain amount of toner is left on the cleaning sleeve 32 side, and this becomes toner in the cleaning agent C. The toner collecting roller 33 rotates clockwise, and a collecting blade 34 made of an elastic rubber or an elastic metal plate abuts on the roller 33, whereby the toner adhered on the collecting roller 33 is moved downward. It will be scraped.
The scraped toner is discharged to a screw conveyor.
It is discharged out of the cleaning device by 35.

On the other hand, the cleaning agent C on the cleaning sleeve 32
Is further transported, and at the doctor blade section 36,
The thickness of the cleaning agent C is regulated to be, for example, about 0.5 to 2.0 mm, enters the cleaning area X again, and such an operation is repeated.

The above-described doctor blade section 36 includes a photosensitive member 18 and a cleaning sleeve 32 so that proper cleaning is performed.
And a regulating means for regulating the amount of the cleaning agent conveyed to the cleaning area X between them.

As described above, the image forming apparatus constituted as a copying machine shown in FIGS. 1 and 2 has a latent image carrier formed of a photoreceptor 18 on which a toner image is formed at the time of an image forming operation, and is opposed to the carrier. Between the latent image carrier and the agent carrier, the carrier carrying a cleaning sleeve 32 for carrying the agent C while carrying the agent C by magnetic force and forming a magnetic brush made of the agent C. And a doctor blade portion 36 which is an example of a regulating means for regulating the amount of the agent C conveyed to the region X. Such a configuration is common to all configuration examples described later.

Specific examples of the components of the copying machine shown in FIGS. 1 and 2, particularly, the cleaning device 27 thereof, are as follows.

(1) the magnetic flux density at the pole of the magnet 31 shown in FIG. 2 by the symbol P _1: 1000 to 1100 Gauss (2) also the magnetic flux in the magnetic poles of the magnet 31 shown by symbol P ₂ Density: 1200-1300 gauss (3) position of the magnet P ₁ constituting the main pole: a line connecting the centers of the cleaning sleeve 32 and the photosensitive member 18 L
As shown in FIG. 2, the angle between the reference line and a line 1 passing through the center of the cleaning sleeve 32 is defined as positive (+),
Negative (-) and when determined, was placed a magnet P ₁ -2 ° to + 8 °.

(4) Bias voltage applied to the cleaning sleeve 32 by the power supply 41: DC-150 V (5) Bias voltage applied to the toner collecting roller 33 by the power supply 42: DC-500 V (6) The cleaning sleeve 32 during normal cleaning operation Linear speed (peripheral speed) (v _s ): 300 mm / sec (7) Linear speed (peripheral speed) of photoconductor 18 (v _p ): 200 mm / sec (8) Cleaning sleeve 32 and doctor blade section 36
(9) Gap between cleaning sleeve 32 and photoreceptor 18: 1.0 mm (10) Concentration of toner of cleaning agent C to carrier: 0.5 to 2% by weight (11) Toner in cleaning agent C Charge amount: 10-80μc
/ g (12) Carrier shape of cleaning agent C: irregular type As described above, the general configuration of the copying machine and its cleaning device 27 has been described.
Of the toner that has migrated from the photoreceptor 18 to the cleaning sleeve 32 side, the toner having a low charge amount or the toner that has not been fully charged despite the charging action of the pre-cleaning charger 28 floats away from the cleaning sleeve 32. However, this may adhere to the photoconductor again. In addition to the cleaning device 27, the developing devices 21Y, 21M, 21C, 21B
For example, toner floating on the surface of the photoreceptor 18, paper powder of transfer paper, or additives contained therein, adhere to the surface of the photoreceptor 18. The toner, paper powder, and the like thus adhered to the surface of the photoreceptor may be fixed as a thin film over time. This is the filming phenomenon described above, and when this occurs, the sensitivity of the photoreceptor 18 becomes uneven, and the density unevenness of the toner image formed on the surface thereof or the background stain occur. Therefore, it is necessary to remove the filming formed on the photoconductor at an early stage or to prevent the occurrence of the filming.

In the illustrated copying machine, the cleaning device 27 is used to remove filming.
That is, at a time other than the time of image formation for forming a toner image on the photoconductor 18 as described above, a larger amount of the cleaning agent C is applied to the area X between the photoconductor 18 and the cleaning sleeve 32 than during the normal cleaning operation. The photosensitive member 18 is operated in a state where a larger amount of the cleaning agent C is packed in this area X than during the feeding and cleaning operations. In this way, the agent pool is formed in the cleaning region X, and the carrier particles in the cleaning agent C are strongly rubbed against the surface of the rotating photoreceptor 18 so that the above-described filming formed on the photoreceptor surface is performed. Can be scraped. That is, the contact pressure and the friction coefficient between the magnetic brush made of the cleaning agent C and the photoreceptor surface can be increased, and the effect of removing filming can be enhanced. As described above, the filming removing operation is executed for a predetermined time at an appropriate time other than the image forming operation, so that the filming on the photoconductor 18 can be removed or the occurrence of the filming can be prevented. Even if there is some eccentricity in the drum-shaped photoreceptor 18, the cleaning agent is accumulated in the cleaning area X and removes filming, so that filming removal unevenness does not occur.

The above configuration is referred to as a first configuration example for convenience.

As shown in the illustrated cleaning device 27, in a cleaning device that transports the cleaning agent C on the cleaning sleeve 32 by rotating the cleaning sleeve 32 while fixing the magnet 31, the cleaning agent C is transferred to the cleaning area X as described above. In order to increase the feeding amount, the rotation speed of the cleaning sleeve 32 may be made slower than during a normal cleaning operation. If the linear velocity of the cleaning sleeve 32 decreases, the cleaning agent C
The cleaning agent C is strongly attracted to the surface of the cleaning sleeve 32. As a result, the amount of the cleaning agent C passing through the doctor blade 36 increases, and the amount of the cleaning agent C conveyed to the cleaning area X increases.

According to the experiment, the linear velocity of the cleaning sleeve 32 v _s,
When the linear velocity of the photoreceptor 18 is v _p and a large amount of the cleaning agent C capable of scraping filming is conveyed to the cleaning area X, that is, when the linear velocity of the cleaning sleeve is reduced, 0 <| _{v s / v p | <0.5} ( rotational speed of the cleaning sleeve 32, for example, about 10 rpm) were able to scrape efficiently filming setting v _s, v _p to satisfy. That is, agent carrying member is conveyed and the carried material Ueno agent by driving rotation, when the linear speed of the linear velocity of the time-carrying member v _s latent image bearing member was set to v _p, filming removal operation sometimes when conveying the amount of agent that can be scraped off filming 0 <| it is the <providing a control means for setting a v _s and v _p to satisfy 0.5 | v _s / v _p.

The above configuration is referred to as an eighth configuration example for convenience.
Is applicable not only to the first configuration example but also to each configuration example described later.

During normal cleaning operation, for example, | v _s / v _p
|> Each linear velocity is set to satisfy 0.5.

Next, a more specific operation example of the above-described first configuration will be described with reference to FIG.

In FIG. 3, when the main switch of the copying machine is turned on, the photoconductor cleaning operation starts. That is, the photoconductor driving motor operates, the photoconductor 18 starts rotating, and the cleaning sleeve driving motor operates to rotate the cleaning sleeve 32 clockwise in FIG. As a result, as described above, the toner remaining on the photoconductor 18 adheres to the cleaning agent C on the cleaning sleeve 32, more precisely, the carrier thereof, and the photoconductor 18 is cleaned.

After performing the above-described cleaning operation for a predetermined time, a filming removing operation is started. At this time, the rotation speed of the cleaning sleeve 32 is reduced to a low speed (0 <| v
_s / v _p | <0.5) to increase the transport amount of the cleaning agent to the cleaning area X and scrape the filming on the photoreceptor 18.

As an example of v _s / v _p at the low speed rotation of the cleaning sleeve 32, a _{v s / v p = 17mm /} sec / 300mm / sec = 0.06.
The Figure 4 shows an example of the relationship between the amount of cleaning agent to be conveyed to the linear speed of the cleaning sleeve 32 v _s and the cleaning area X (FIG. 2), a cleaning sleeve 32 is slow As can be seen Then, the transport amount of the cleaning agent increases, and the effect of removing filming is enhanced.

Further, T shown in FIG. 3 is a rise time from the end of the above-described photosensitive member cleaning operation to the time when each element of the copying machine, for example, the fixing device rises to a predetermined temperature. In the example of FIG. The filming removal operation is performed only for the time indicated by t.
Alternatively, the filming removal operation may be performed over the entirety. This is the meaning of the “extended range of the filming removal operation” shown in FIG.

When the rise time T has elapsed, the copying machine is ready for copying, and by turning on the copy switch here,
The image forming operation (copy operation) is started.

During a series of image forming operations and at the end as shown in FIG. 3, a photosensitive member cleaning operation is performed, and then a filming removing operation is performed. That is, the cleaning sleeve 32 is rotated at a low speed to increase the transport amount of the cleaning agent to the cleaning area X.

As can be seen from the above example, the filming removing operation can be executed at an appropriate time other than the time of image formation.

As described above, according to the first configuration example, the photosensitive member 18 is not operated at a time other than the image forming operation of forming a toner image on the photosensitive member 18.
The filming can be effectively removed by transporting the cleaning agent in an amount sufficient to scrape the above filming to the area X between the photoconductor 18 and the cleaning sleeve 32. At that time, no special member for removing filming is required at all, and the cost of the apparatus can be reduced. Moreover, unlike the conventional case, in which a polishing brush or blade is pressed against the photoconductor to remove filming, an excessive external force is not applied to the photoconductor.
There is no danger that the photoreceptor 18 will be worn out early or damaged to shorten its life.

In the first configuration example described above, a large amount of the cleaning agent is conveyed to the cleaning area X during the filming removal operation. Instead of this configuration, a toner image is formed on the latent image carrier including the photoreceptor 18. During the filming removing operation other than the image forming operation, the rotation of the cleaning sleeve 32 is stopped to stop the transport of the cleaning agent C while the photoconductor 18 is being rotated, and the cleaning agent C is stopped between the photoconductor 18 and the cleaning sleeve 32. Even if the existing cleaning agent is captured by the magnetic force of the magnet 31 and the filming operation of the photoconductor 18 is executed by the magnetic brush, the filming can be effectively removed or the occurrence thereof can be prevented beforehand. it can.
By rotating the photoreceptor 18 and stopping the cleaning agent, the contact pressure between the magnetic brush and the photoreceptor surface and the coefficient of friction therebetween are increased, and an effect of removing filming on the photoreceptor 18 is obtained. When the cleaning agent stops, the toner on the carrier in the cleaning agent that comes into contact with the photoreceptor 18 is immediately taken off by the photoreceptor 18, or the toner in the cleaning agent part that comes into contact with the photoreceptor 18 starts from the part that comes into contact with the photoreceptor 18 The carrier escapes sideways and the carrier comes into direct contact with the surface of the photoreceptor, whereby the carrier comes into strong contact with the surface of the photoreceptor, and the filming removal effect is enhanced. This configuration is referred to as a second configuration example.

FIG. 5 shows a timing chart of the second configuration example. At the time of the filming removal operation, the photoconductor driving motor operates to rotate the photoconductor 18, the cleaning sleeve driving motor does not operate, and the cleaning sleeve 32 stops rotating. Is different. Other configurations and operations are the same as the previous example.

The filming can be removed by stopping the cleaning agent during the filming removing operation as in the above-described second configuration example. However, with this configuration alone, when the photoconductor 18 is eccentric, In some cases, the contact pressure between the photoreceptor 18 and the magnetic brush does not contact, or even if it does, the contact pressure is extremely weakened, and the filming removal effect may be reduced. In this case, uneven filming removal occurs.

Therefore, in the third configuration example, during the filming removing operation other than the image forming for forming the toner image on the photoconductor 18, the cleaning sleeve is kept rotating while the photoconductor 18 is rotated.
The step of stopping the rotation of the cleaning agent 32 to stop the transport of the cleaning agent and the step of rotating the cleaning sleeve 32 to transport the cleaning agent are repeated one or more times. According to this, the cleaning agent C
When the conveyance is stopped, an operation of removing filming on the photoreceptor 18 by a magnetic brush is performed as in the second configuration example described above. Next, the cleaning agent is conveyed while being carried on the cleaning sleeve 32. Therefore, even if the photoconductor 18 is eccentric, the magnetic brush changes its form while following the photoconductor 18 and comes into contact with the photoconductor 18. Since such an operation is repeated, the magnetic brush and the photoreceptor 18 come into positive contact with each other, and it is possible to prevent the occurrence of unevenness in removing the filming on the photoreceptor 18.

In addition, since the carrier in contact with the photoreceptor 18 changes due to the movement of the cleaning agent during the filming removing operation, the filming removing effect can be further enhanced.

As described above, in the third configuration example, at the time of the filming removing operation other than the image formation for forming the toner image on the latent image carrier, the conveyance of the agent is stopped while the latent image carrier is being operated, So as to repeat the agent transport operation at least once each
Control means for controlling the transport and stop of the agent is provided.

FIG. 6 shows an example of a timing chart of the third configuration example described above. At the time of the filming removal operation, the photosensitive member drive motor operates to rotate the photosensitive member 18, and the cleaning sleeve drive motor repeats the operation and stop, and the cleaning sleeve 32 stops and repeats, thereby conveying the cleaning agent. The stop is executed, and the filming on the photoconductor 18 is removed. The time for stopping and operating the cleaning sleeve 32 can be set as appropriate. Other configurations and operations are the same as those of the first configuration example.

By the way, in the first configuration example described above, the rotation speed of the cleaning sleeve 32 differs between the normal cleaning operation and the filming removal operation. This control is, for example, a control shown only schematically in FIG. This can be done by means. That is, the cleaning sleeve drive motor M1 that drives the cleaning sleeve 32 is a pulse motor, and the output from the CPU 65 is input to the cleaning sleeve drive motor M1 via the driver 66, and the motor M1
Is driven. At that time, during the normal cleaning operation,
At the time of the filming removing operation, the cleaning sleeve drive motor M1 is driven and controlled at a speed suitable for each of the cleaning operation and the filming removing operation by each output from the CPU 65, and the cleaning sleeve 32 is adapted for each of these operations. Drive at speed.

As described above, in the example shown in FIG. 7, the cleaning sleeve driving motor M1, the driver 66, and the CPU 65 operate the cleaning sleeve driving motor M1, the driver 66, and the CPU 65 in a timely manner other than when forming an image for forming a toner image on the latent image carrier (photoconductor 18). Controlling the amount of the agent to be conveyed to the region between the latent image carrier and the agent carrier (cleaning sleeve 32) in such a manner that the amount of the agent capable of scraping the filming on the latent image carrier is transferred. This constitutes control means.

M2 in FIG. 7 is a photoconductor driving motor driven via a driver 69 by a command from the CPU 65.

By the way, when a large amount of the cleaning agent C is sent to the cleaning area X during the filming removing operation as described above, the amount of the cleaning agent accumulated in this area increases sequentially,
Here, the agent C becomes clogged, and this effectively performs the filming removing action. However, the clogged cleaning agent exerts a large load on the sleeve 32 and the photoreceptor 18 due to a frictional force. It may increase gradually and eventually stop the photoconductor 18 and the sleeve 32. Such a state is referred to as a blocking state.In this state, not only the cleaning sleeve drive motor M1 and the photoconductor drive motor M2 are stopped, but also the removal of filming is not performed, and the blocking state is prolonged. If it continues, the meaning of sending a large amount of the cleaning agent C into the area X will be lost.

In order to prevent an excessive load (frictional force) from being applied to the cleaning sleeve 32 and the photoreceptor 18, the cleaning agent C
It is conceivable to reduce the supply amount of the toner or to widen the gap between the photosensitive member 18 and the cleaning sleeve 32. However, in this case, the filming removing effect is reduced.

Therefore, in the fourth configuration example, at the time of the filming removing operation, the rotation speed of at least one of the cleaning sleeve 32 and the photosensitive member 18 is detected, and when the rotation speed becomes zero or less than a predetermined value, the film is conveyed to the area X. This reduces the amount of cleaning agent to be applied, reduces the load acting on the cleaning sleeve 32 and the photoreceptor 18, and prevents them from being stopped.

During the filming removal operation other than the image formation for forming a toner image on the latent image carrier, an amount of the agent capable of scraping the filming on the latent image carrier is applied to the latent image carrier and the agent carrier. Detecting means for detecting the number of rotations of at least one of the agent carrier and the latent image carrier in a state where the carrier is transported to the area between at least one of the agent carrier and the latent image carrier during the filming removal operation. When the number of rotations becomes zero or a predetermined value or less is detected by the detection means, a control means for controlling the transport amount of the agent is provided so that the amount of the agent transported to the area decreases. .

In the example shown in FIG. 7, the number of revolutions of the cleaning sleeve drive motor M1 is detected by a number of revolutions detection circuit 67 including, for example, an encoder or a photo interrupter, and the output is input to the CPU 65. Here, the rotation number of the cleaning sleeve 32 is reduced until the cleaning sleeve 32 stops and the state immediately before the above-described blocking state is reached.
When it is detected that the rotation speed of M1 has dropped to, for example, 10 to 20 rpm (the rotation speed of the cleaning sleeve 1 to 2 rpm) or less, the cleaning sleeve drive motor M1 is immediately driven by the command from the CPU 65 via the driver 66. Is increased to, for example, about 1800 rpm (180 rpm of the cleaning sleeve 32) during a normal cleaning operation. By detecting the rotation speed of the cleaning sleeve drive motor M1 as described above, the rotation speed of the cleaning sleeve 32 is detected, and when the rotation speed becomes equal to or less than a predetermined value, the rotation speed of the cleaning sleeve 32 is increased. The centrifugal force acting on the cleaning agent C carried on the cleaning sleeve 32 increases, and the cleaning agent C easily slips on the surface of the cleaning sleeve 32. Therefore, the cleaning agent C is transported to the region X through the doctor blade 36. The amount of C decreases, for example, to the same extent as during a normal cleaning operation. As a result, before the photosensitive member 18 and the cleaning sleeve 32 are stopped, the load can be reduced before a large load is applied to the photosensitive member 18 and the cleaning sleeve 32. The stop of the cleaning sleeve drive motor M1 can be prevented.

If the cleaning sleeve 32 rotates at a high speed during one or more rotations, blocking can be prevented. After a while, the cleaning sleeve
The number of rotations of 32 is reduced again, the amount of the cleaning agent C conveyed to the region X is gradually increased, and the filming removing operation is performed. Thus, the occurrence of the blocking state can be dealt with in a short time.

When the state becomes close to the blocking state again, the above-described operation is executed again. Performing such an operation for a predetermined time,
The filming removal operation ends. If the cleaning sleeve 32 is rotated at a high speed to reduce the transport amount of the cleaning agent C to the region X, the filming cannot be removed during this time. Is desirable.

Further, as described above, since the adverse effects caused by the occurrence of the blocking state can be removed, the cleaning sleeve 32 and the photosensitive member 18 can be removed.
Can be set to an optimum size for cleaning and filming removal without any consideration of blocking, so that the cleaning effect and the filming removal effect can be further enhanced.

Even if the cleaning sleeve 32 detects that the cleaning sleeve 32 is in the blocking state, that is, completely stops, and the number of revolutions has become zero, and after the detection, it is immediately controlled to increase the number of revolutions of the cleaning sleeve drive motor M1. Good.

As shown in FIG. 7, the rotation speed of the photoconductor drive motor M2 is detected by the rotation speed detection circuit 68 during the filming removing operation, and the rotation speed is maintained until the photoconductor 18 is in the blocking state or the state immediately before the blocking state. When the rotation speed of the cleaning sleeve drive motor M1 is increased in exactly the same manner as described above (for example, when the rotation speed of the 32 may be rotated at a high speed to reduce the transport amount of the cleaning agent to the region X.

Both rotation speed detection circuits 67 and 68 may be provided to detect the rotation speeds of the cleaning sleeve drive motor M1 and the photoconductor drive motor M2, respectively, or only one of the rotation speed detection circuits 67 and 68 may be provided. It may be. In the present embodiment, such a rotation speed detecting circuit constitutes a detecting means for detecting the rotation speed of at least one of the agent carrier (cleaning sleeve 32) and the latent image carrier (photoconductor 18). Instead of such a detecting means, the detecting means may be constituted by a detecting device for detecting at least one of the input currents of the cleaning sleeve drive motor M1 and the photoconductor drive motor M2. That is, when an overload of the cleaning agent C is applied to the motors M1 and M2, an overcurrent flows through these motors, and this can be detected to detect a blocking state or a state close to the blocking state.

Similarly, in this example, the doctor blade unit 36, the CPU 65, and the rotation speed control circuit 66 operate to transfer the agent so that the amount of the agent transferred to the region X decreases when the rotation speed becomes zero or less than a predetermined value. This constitutes an example of a control means for controlling the amount.

During the filming removal operation, the cleaning sleeve 32 is driven while uniformly repeating the low speed and the high speed,
For example, at low speed _{0 <| v s / v p} | meet <0.5, during high speed | v _s / v _p | cleaning to satisfy the> 0.5 sleeve 32
Even if the linear velocity of the photosensitive member 18 is set, the same effect as in the fourth configuration example can be obtained. However, according to this configuration, the cleaning sleeve is operated at a high speed to reduce the transport amount of the cleaning agent C to the region X. Even when cleaning is not necessary, the cleaning sleeve 32 is uniformly driven at a certain point of time at a high speed, which may reduce the filling removal effect.

Next, FIGS. 8 and 9 show a fifth configuration example. The general structure and operation of the cleaning device 27 shown in FIG. 8 and the copier to which the cleaning device 27 is attached are the same as those described above with reference to FIGS. 1 and 2.

In the fifth configuration, the opposing magnets 70 is an example of the opposite magnetic poles inside the photosensitive body 18 with respect to magnet P ₁ in the cleaning sleeve 32, are located on opposite sides of the photosensitive member 18. Opposing magnets 70 are disposed toward the S pole to the N pole of the magnet P _1, the rotation center and the rotation center of the drawing the line L connecting the left of the photoreceptor 18 of the cleaning sleeve 32, i.e. slightly to the left area of the cleaning area X Are shifted from each other.

The opposing magnet 70 is fixed to the arm 71, and this arm
The base end of 71 is attached to the support plate 72. The support plate 72 can swing about a support shaft 73, and the tip of the support plate 72 is attached to a plunger 75 of a solenoid 74.

Opposing magnet by arm 71, support plate 72, and support shaft 73
Support means for supporting the magnet 70 is provided, and moving means for moving the opposed magnet 70 by the solenoid 74 is provided.

A time other than the time of image formation for forming a toner image on the photoconductor,
For example, during a few seconds to several minutes immediately after the main switch of the copier is turned on, or during a filming removing operation after a predetermined image formation, the opposing magnet 70 approaches the position shown by the solid line in FIG. Occupy the first position. Thus, the magnetic field in the opposite region X between the between the magnet P ₁ and the opposing magnet 70, i.e. the cleaning sleeve 32 and the photosensitive member 18 is formed.

With the action of the magnetic field, the magnetic brush B made of the cleaning agent C is held in the facing region X, and the magnetic brush B is pressed against the photoreceptor 18 with a relatively large force.
Filming of the rotating photoconductor 18 is removed.

At times other than the filming removal operation, the solenoid
By the excitation of 74, the plunger 75 is attracted, and the support plate 72 swings about the support shaft 73 as shown by a dotted line,
71 rotates, and the opposing magnet 70 is separated from the cleaning sleeve 32. Opposing magnets 70 is separated from the cleaning sleeve 32, when retracted to a second position shown by the dotted line, there is no substantial magnetic field between the opposed magnets 70 and the magnet P _1, pressed against the photosensitive member 18 until it The cleaning of the magnetic brush B is released by the rotation of the cleaning sleeve 32.

As described above, the opposing magnet 70 may be held at the first position during the filming removing operation. However, during one filming removing operation, the opposing magnet 70 is moved to the first position and the second position. The magnetic brush B of a new cleaning agent C may be formed each time the opposing magnet 70 reaches the first position.

In the example shown in FIGS. 8 and 9, the opposing magnet 70 is arranged on the left side of the opposing region X in the drawing.
There when spaced from the cleaning sleeve 32, even if the discrete cleaning agent constituting the magnetic brush B is, the cleaning agent, since it always passes through the cleaning region X, the cleaning agent by a magnetic force of the magnet P ₁ Therefore, the agent is not adhered to the photoreceptor 18 and conveyed, and does not spill out of the cleaning device 27.

In the above embodiment, the permanent magnet 70 is used as the opposed magnetic pole. However, an electromagnet may be used instead, or a magnetic material such as a ferromagnetic material or a soft magnetic material may be used. The filming removal effect may be enhanced by using the first configuration example in which the rotation speed of the cleaning sleeve 32 is reduced in conjunction with the operation of bringing the opposing magnet 70 closer to the cleaning sleeve 32. Further, the cleaning sleeve 32 may be stopped or driven during the filming removing operation.

The filming removing operation in each of the above-described configuration examples is performed using the time and the waiting time between a series of image forming operations as described above. For example, in order to obtain a predetermined number of copy sheets for a certain document. The filming elimination operation is performed at a time after a series of copying operations or before a series of copying operations, so that a high quality toner image is always obtained. If the execution time of the operation is too short, filming cannot be completely removed. Conversely, if the execution time is too long, unnecessary stress is applied to the carrier in the cleaning agent C, and the life of the carrier is shortened. Ideally, the filming removal operation is performed only for a minimum time in which filming can be sufficiently removed.

On the other hand, the amount of filming generated on the surface of the photoreceptor 18 is substantially proportional to the time of the image forming operation (copying operation), in particular, the operating time of the developing device. For this reason, if the filming removal operation time is set to a predetermined fixed time, the filming removal operation time may be too short or too long depending on the length of the image forming operation before performing this operation. Failure occurs.

When the copying operation is continuously performed for a long time, the cleaning sleeve 32 continues to rotate for a long time to perform the cleaning operation, and the developing sleeve is rotated for a long time, and the photosensitive member is rotated.
Filming material easily accumulates on the surface. In such a case, it is desirable to extend the filming removal operation time, and conversely, to shorten the filming removal operation time when the copy time is short so as to suppress the deterioration of the carrier in the cleaning agent C. is there.

Therefore, in the sixth configuration example, there is provided a control unit for setting the time for executing the various filming removing operations described above to be longer as the time of the image forming operation before the execution of the operation is longer. . This makes it possible to set the filming removal operation to the above-described ideal time.

FIG. 10 shows the ideal length of the developing operation time during which the developing sleeve 50B of the black developing device 21B shown in FIG. 1 is continuously rotated to perform the developing operation, and the length of time during which the filming removing operation is performed after the end of this operation. An example of a typical relationship is shown. For example, when performing the 100 seconds development operation, it may be carried out only filming removing operation time indicated by t _1. If the filming removing operation is performed for a longer time, unnecessary stress is applied to the carrier in the cleaning agent. Short kite than filming removing operation time conversely t _1, removal of the filming is insufficient.

When a full-color toner image is obtained by the other developing devices 21Y, 21M, 21C, the developing rollers 50Y, 50M,
The filming removal operation time is set according to the total value of the time that the 50C has rotated until the series of image forming operations is completed.

Instead of detecting the operation time of the developing device and setting the filming removal operation time, the number of copy sheets obtained by a series of image forming operations is detected, or the time from the start to the end of the series of image forming operations is determined. Measured by a timer, etc.
The filming removing operation may be executed only for a time corresponding to these.

According to the above configuration, when a series of image forming time is short, for example, when only one copy sheet is obtained from one document, the filming removing operation time is also short. The power consumption required to rotate 32 can be reduced, and running costs can be reduced.

The sixth configuration example can be applied to the case where the cleaning sleeve 32 is driven while repeating the low speed and the high speed during the filming removing operation as described above. In this case, the actual filming removing operation is performed intermittently a plurality of times, and the total of these times is the filming removing operation time shown in FIG. 10 and described above. Is natural.

By the way, the filming removing operation shown in each of the above configuration examples is performed after the end of a series of image forming operations.
When the operator turns on the copy switch of the copying machine to execute image formation during the filming removing operation, the image forming operation may be prohibited by giving priority to the filming removing operation. it can.

Figure 11 (a) is a timing chart based on this configuration, after completion of image forming operation over time indicated by T1 (copying operation), only the filming removing operation time indicated by t ₁ to a predetermined Execute, but image formation is disabled during this operation, and image formation is disabled on the display lamp of the display unit for copy enable display from the start of the image formation operation to the end of the filming removal operation. , For example, light red. When the filming removal operation is completed, the lamp is changed to green, and an image can be formed (copying is possible).
Is displayed. In this way, the filming removal operation can be performed reliably for a predetermined time, and occurrence of filming can be prevented. However, according to this configuration, it is not possible to make a copy until the filming removing operation is completed, which may inconvenience the operator.

Therefore, in the seventh configuration example, as shown in FIG. 11 (b), when the image forming operation for the time T1 is completed, the image forming is enabled, and the display lamp is switched from red to green. Show this. And in this case in advance only determined time t ₁ filming removal operation after the completion of image formation also takes place, in this during the removal operation, as shown in FIG. 11 (c), a copy switch is turned on by the operator,
When an image forming command is input, the filming removing operation is interrupted, and the image forming is executed with priority. In this way, there is no inconvenience to the operator. However, with this configuration alone, the filming removal operation is interrupted, so that the operation time is insufficient, and there is a possibility that the filming cannot be sufficiently removed. Therefore, after the end of image forming operations performed by certain time T2 by interrupting the filming removing operation as described above, by the time obtained by adding the filming removing operation time missing earlier t _3, filming The removal operation is executed to prevent the occurrence of insufficient filming removal.

As described above, in the seventh configuration example, after the image forming operation is completed, the filming removing operation is performed for a predetermined time, and when the image forming command is input, the filming removing operation is performed. The image forming apparatus further includes a control unit that suspends the image formation, gives priority to the image formation, and adds the shortage of the filming removal operation to perform the filming removal operation after the image formation is completed.

Next, a more specific configuration example in which the above-described seventh configuration example and the above-described sixth configuration example are combined will be described.

FIG. 12 is a block diagram showing this specific example, and FIG. 13 is a flowchart thereof. In FIG. 12, reference numeral 65 denotes a CPU of a copying machine, reference numeral M3 denotes a developing motor composed of a pulse motor for rotating and driving the developing sleeve 50B of the black developing device 21B shown in FIG. 1, and M1 also denotes the example of FIG. The cleaning sleeve drive motor drives the cleaning sleeve 32.

First, the copy switch of the input unit 58 is turned on, and an image forming command is input to the CPU 65. Here, it is assumed that a black-and-white copy image forming operation is performed by this (the thirteenth embodiment).
Figure (a). At this time, the developing motor M3 is driven via the driver 56 by a command from the CPU 65, whereby the developing sleeve 50B (FIG. 1) is driven to perform the developing operation. At this time, the image forming operation time, more precisely, the operation time of the developing motor M3 is counted by the counter (or timer) of the CPU 65 (FIG. 13 (b)), and the value is calculated.
It is stored in the RAM 80 (FIG. 12).

Here, the time of this image forming operation is shown in FIG.
Suppose that it is T1 as shown in FIG. Also ROM81
(FIG. 12) previously stores the curve shown in FIG. 10 or a function f (T ₀ ) approximated thereto.

After the image forming operation is completed (FIG. 13 (c)), the image forming time T1 stored in the RAM 80 and the function f (T
₀ ), the optimum filming removal operation time f (T
1) is set by the CPU 65 (FIG. 13 (d)). That is, as illustrated above with reference to FIG. 10, when the developing operation time T1 is 100 seconds, than filming removing operation time is set to t _1. The cleaning sleeve drive motor M1 is driven by a command from the CPU 65.
57 through, is driven at the set by a time t ₁ slow as described above, by rotating the sleeve 32 at a low speed, execute a filming removing operation as described above (13
Figure (e). Although the filming removing operation is based on the first configuration example, the filming removing operation may be performed using another configuration example.

The operation according to the sixth configuration example can be executed as described above.

On the other hand, when performing the above-described filming removal operation, the CPU 6
The time is counted by the counter of 5, and this is RAM
This is stored in the memory 80 (FIG. 13 (f)). And whether reached filming removing operation set time t ₁ is checked (the
(FIG. 13 (g)), if it has reached, the filming removing operation is stopped and a waiting period is made (FIG. 13 (h), (i)).

If it does not reach the set time t ₁ is whether the copy switch is turned on is checked (FIG. 13 (j)).
Here, when the copy switch is turned on,
Filming the removal operation after the start t ₂ as shown in FIG. (C) (<
When the copy switch is turned on after t ₁ ),
Based on these times t ₁ and t ₂ stored in the RAM 80, respectively, the CPU 65 calculates a filming elimination operation shortage time t ₁ −t ₂ and stores it in the RAM 80 (FIG. 13 (k)). .

Next, an image forming operation based on the copy switch-on is performed (FIG. 13 (l)), and the operation time T2 at this time is shown.
(FIG. 11 (c)) is counted (FIG. 13 (m)), and this is stored in the RAM 80. Next, when the image forming operation is completed (FIG. 13 (n)), the filming removal operation time is set again here (FIG. 13 (o)). Here, ROM8
F (T ₂ ) is set based on the function f (T ₀ ) stored in _{1 and} the sum t of this value and t ₁ −t ₂ previously stored in the RAM 80
₃ (FIG. 11 (c)) is set as the filming removal operation time, and the filming removal operation is executed only during this time (FIG. 13 (e)). the value of f (T2) is an ideal filming removing operation time required by the image forming operation over time of T2, this, the lack of time t ₁ -t ₂ of the previous filming removal operation in addition The filming removal operation is performed only for the set time. As a result, there is no shortage of the removal time, and there is no excessive filming.

When performing the filming removing operation in each of the configuration examples described above, the photosensitive member 18 was rotated at the same speed as that during the normal image forming operation, but the photosensitive member 18 was rotated during the removing operation during the normal image forming operation. Rotating at a higher speed can increase the filming removal efficiency. Control means is provided for making the linear velocity of the latent image carrier faster during the filming removing operation than during the image forming operation. This is a ninth configuration example.

The ninth configuration example can be applied to all of the above-described configuration examples. However, as in the first configuration example, the cleaning sleeve 32 is driven at a low speed during the filming removal operation, and the cleaning agent When the ninth configuration example is applied to a combination of the configuration for increasing the transport amount of the above and the eighth configuration example, the advantage can be particularly utilized. That is, in the eighth configuration example, 0 <| v _s / v _p | <0.5 is set in the filming removing operation. Is also possible. However, if the cleaning sleeve 32 is rotated at a too low speed, the motor for driving the sleeve and the rotation of the sleeve 32 may become unstable.

Therefore, if the photosensitive member 18 is rotated at a high speed during the filming removing operation, the above expression can be satisfied without rotating the cleaning sleeve 32 at such a low speed.

FIG. 14 shows a timing chart similar to FIG. 3 when the ninth configuration example is applied to the first configuration example. In the case of FIG. 14, the photoconductor drive motor M2 for driving the photoconductor 18
(FIG. 7) is constituted by a variable speed motor, for example, a pulse motor, whose rotation speed is controlled by a command from the CPU. In a normal image forming operation, the photosensitive member is exemplified as described above. For example, the cleaning sleeve 32 is rotated at a speed of 200 mm / sec, and the cleaning sleeve 32 is rotated at a speed of 300 mm / sec. During the filming removing operation, the cleaning sleeve 32 is driven at a low speed and the photoconductor 18 is driven at a high speed. 3 differs from FIG. 3 only in that the photoconductor 18 is rotated at a high speed during the filming removing operation.

In the above description, the cleaning sleeve 32 of the cleaning device 27 is taken as an example of the agent carrier, and the cleaning agent C is carried on the cleaning sleeve 32, and the filming is removed by using the cleaning agent C. Developing device 21 illustrated in FIG.
Like Y, 21M, 21C, 21B, there is a developing sleeve 50Y, 50M, 50C, 50B that carries and conveys a developer composed of a mixed powder of toner and carrier by magnetic force, and regulates the amount of developer conveyed. When the doctor blade 51 is provided, filming of the photoreceptor can be removed by using the doctor blade 51 in the same manner as in the respective configuration examples described above.

That is, the developer forms an agent for scraping filming, the developing sleeve constitutes an agent carrier for carrying the agent, and the doctor blade portion is transported to an area between the latent image carrier and the agent carrier. And a regulating means for regulating the amount of the cleaning agent, the cleaning agent C, the cleaning sleeve 32 and the doctor blade of each of the constitution examples described above.
If you correspond to each 36, each of the preceding configuration examples,
It can be applied to a developing device.

For example, in order to apply the first configuration example to a developing device, at least one of the developing sleeves 50Y, 50M, 50C, and 50B constituting the agent carrier is operated at a low speed during a filming removing operation other than the image forming operation. By rotating the photoconductor 18, a large amount of the developer (in this example, the developer) is conveyed to the facing region between the photoconductor 18 and the developing sleeve to remove the filming of the photoconductor 18. The same applies to other configuration examples.

It goes without saying that the above-described respective configuration examples using the cleaning device or the developing device can be employed in a single-color copying machine having only one developing device.

At this time, the agent C carried on the cleaning sleeve 32
Is generally lower in toner concentration than the developer on the developing sleeve.
The configuration in which the filming is removed by rubbing with the toner increases the probability that the carrier particles in the agent hit the photoreceptor, and the filming removal effect can be further enhanced.

As the carrier of the cleaning agent C, as described above, it is advantageous to use irregular carrier, that is, angular carrier particles in order to enhance the cleaning effect of the photoconductor. The effect of scraping filming from is also increased. Since the carrier particles in the developer on the developing sleeve are usually spherical, the effect of scraping the filming on the photoreceptor is slightly reduced.

As described above, the present invention can be applied to both the cleaning device and the developing device, but the application to the former is more effective.

If the filming is removed by both the developing device and the cleaning device, the filming can be effectively scraped off in a shorter time.

In the configuration example described above, an example is shown in which the cleaning sleeve 32 or the developing sleeve is driven to rotate and the magnet provided therein is fixed, but the cleaning sleeve or the developing sleeve is fixed as is well known per se. The cleaning agent C or the developer can be conveyed by rotating the magnet inside thereof or by rotating both the magnet and the sleeve. The present invention can be applied to such a case. Also in this configuration, the amount of the cleaning agent C or the developer conveyed to the region between the sleeve and the photosensitive member 18 can be controlled by controlling the rotation speed of the magnet or the sleeve.

In each of the above configuration examples, the cleaning sleeve 32
In this example, a large amount of the cleaning agent C is fed to the region X by lowering the rotation speed of the cleaning agent. However, instead of transporting a large amount of the cleaning agent to the region X by such a means, as shown in FIG. A doctor blade 136 corresponding to the doctor blade portion 36 is supported so as to be able to approach or separate from the cleaning sleeve 32, and during a normal cleaning operation, the blade 136 is fixed at a position shown by a solid line. 136 may be separated from the cleaning sleeve 32 as shown by a dashed line, and a gap between them may be widened so that a large amount of the cleaning agent is sent to the region X. As a driving device for operating the blade 136 as described above, for example, a solenoid or a motor can be used. Thus, with the movable blade 136,
By means of a device for driving the same, when the filming removing operation is performed, a means for transporting a large amount of the cleaning agent to the region X or when the rotation speed of the agent carrier or the latent image carrier becomes zero or less than a predetermined value, It is also possible to configure control means for controlling the amount of the agent to be conveyed so as to reduce the amount of the agent to be conveyed. The same applies to the case where the filming is removed by the developing device. The blade 51 shown in FIG. 1 may be movably supported and actuated by a driving device.

The present invention can be applied not only to a copying machine but also to various image forming apparatuses such as a printer and a facsimile, and can be applied to a case where a latent image carrier is a belt-shaped one or a case where an agent carrier is a belt-shaped one. It is possible.

The idea shown in the fourth configuration example in which the amount of agent transported is reduced in order to eliminate the adverse effects of the blocking state can also be employed during a normal cleaning operation. That is, when the cleaning sleeve 32 is performing the cleaning operation, the cleaning agent is clogged between the sleeve 32 and the photosensitive member 18 for any reason, and the cleaning sleeve 32
When the number of rotations of the photoconductor 32 or 32 has decreased, this is detected, for example, by increasing the number of rotations of the cleaning sleeve 32, the amount of the cleaning agent in the region X is reduced,
The overload applied to the sleeve 32 and the photoreceptor 18 is removed.

〔The invention's effect〕

According to the configuration of the first aspect, filming can be effectively removed without significantly shortening the life of the latent image carrier and at low cost.

According to the configuration described in claim 2, in addition to the above-described effects, it is possible to prevent an excessive load from being applied to the latent image carrier and the agent carrier due to the accumulation of the agent between the latent image carrier and the agent carrier. The possible benefits are obtained.

According to the configuration of the third aspect, the same effect as that of the first aspect can be obtained. In addition, the filming removal operation time becomes excessively long, and the deterioration of the carrier is accelerated. Can be prevented.

According to the configuration of the fourth aspect, in addition to the effect of the first aspect, it is possible to eliminate a problem that causes the operator to feel inconvenience,
In addition, there is no shortage of the filming removal operation time.

According to the configuration described in claim 5, filming can be more effectively removed.

According to the configuration described in claim 6, the time efficiency of the filming removing operation can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a copying machine to which the present invention is applied.
FIG. 2 is an enlarged view of the cleaning device, FIG. 3 is a timing chart showing an example of a series of operations including a filming removal operation in the first configuration example, and FIG. 4 is a drawing showing the linear velocity of the cleaning sleeve and the cleaning agent. FIGS. 5 and 6 are graphs showing the relationship with the amount of conveyance, FIGS. 5 and 6 are diagrams similar to FIG. 3 in the second and third configuration examples, and FIG. 7 is an example of a control system of the fourth configuration example. FIG. 8 is a schematic cross-sectional view similar to FIG. 2, showing a fifth configuration example, FIG. 9 is an explanatory view showing main members of the fifth configuration example, and FIG. 11 (a) to 11 (c) are diagrams showing the relationship between the operation time of the developing device and the filming removal operation time, illustrating a configuration example. FIGS. 11 (a) to (c) are timing charts illustrating a seventh configuration example. FIG. 13 is a block diagram showing control means of the sixth and seventh configuration examples, and FIG. , FIG. 14 illustrates the configuration example of the ninth, Figure 3 similar to the timing chart, FIG. 15 is an explanatory diagram showing another example of a means for regulating the transport of agents. C: agent, X: area

──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number Japanese Patent Application No. 1-73475 (32) Priority date Hei 1 (1989) March 24 (33) Priority claim country Japan (JP) (31) Priority Claim No. Japanese Patent Application No. Hei 1-203459 (32) Priority Date Hei 1 (1989) August 5, (33) Priority Country Japan (JP) (72) Inventor Kazuyuki Sugihara 1-3-3 Nakamagome, Ota-ku, Tokyo No. 6 Inside Ricoh Co., Ltd. (72) Inventor Yuji Sawai 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-59-55468 (JP, A) 54-147044 (JP, A) Fully open sho 59-126257 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 21/10-21/12 G03G 15/08 507

Claims (6)

(57) [Claims] A latent image carrier on which a toner image is formed at the time of image formation, and an agent for carrying the agent while being opposed to the carrier and carrying an agent by a magnetic force to form a magnetic brush made of the agent. An image forming apparatus comprising: a toner carrier on a latent image carrier; and a regulating unit configured to regulate an amount of the agent conveyed to an area between the latent image carrier and the carrier. At the time of filming removal operation other than at the time, with the latent image carrier
An image forming apparatus comprising: a control unit configured to control the transport and stop of the agent so that the transport of the agent and the transport operation of the agent are each repeated at least once. 2. A latent image carrier on which a toner image is formed at the time of image formation, and a carrier which is opposed to the carrier, carries the agent by magnetic force, and conveys the agent while forming a magnetic brush made of the agent. An image forming apparatus comprising: a toner carrier on a latent image carrier; and a regulating unit configured to regulate an amount of the agent conveyed to an area between the latent image carrier and the carrier. At the time of filming removal operation other than the time, the amount of the agent that can scrape the filming on the latent image carrier is transported to the area between the latent image carrier and the agent carrier, and Detecting means for detecting the number of rotations of at least one of the body and the latent image carrier, and at the same time, at the time of the filming removing operation, the number of rotations of at least one of the agent carrier and the latent image carrier becomes zero or a predetermined value or less. Was detected by the detecting means. The image forming apparatus further includes a control unit that controls a transport amount of the agent such that an amount of the agent transported to the area decreases. 3. The execution time of the filming removing operation is as follows:
The image forming apparatus according to claim 1, further comprising a control unit configured to set the image forming operation time to be longer as the image forming operation time before performing the operation is longer. 4. When the filming removing operation is executed for a predetermined time after the image forming operation is completed, and when an image forming command is input, the filming removing operation is interrupted and the image forming is prioritized. 4. The image forming apparatus according to claim 1, further comprising: a controller configured to execute the filming removal operation by adding a shortage time of the filming removal operation after the image formation is completed. 5. 5. A dosage conveying the said supported body Ueno agent by the carrier is driven to rotate, when the linear speed of the linear velocity of the time-carrying member v _s latent image bearing member was set to v _p, Phil when conveying the amount of agent that can be scraped off filming during zooming removal operation is _{0 <| v s / v p} | < claims comprising a control means for setting a v _s and v _p to satisfy 0.5 Item 5. The image forming apparatus according to any one of Items 1 to 4. 6. The image forming apparatus according to claim 1, further comprising control means for making the linear speed of the latent image carrier faster during the filming removing operation than during the image forming operation.