JPH03136083A - Cleaning mechanism for image forming device - Google Patents

Abstract

PURPOSE:To prevent dust which sticks on the surface of a stopped photosensitive body, from being brought to an exposure device side when the photosensitive body is restarted by carrying a blade to a retreat position after it is carried from an operating position to a cleaning position in contact with a cleaning brush while it is made contact with the surface of the photosensitive body, after the photosensitive body is stopped. CONSTITUTION:On the completion of an image formation cycle, the photosensitive body 1 is stopped rotating in a direction that its surface traces the exposure device, a developing device, a transfer device and a cleaning mechanism in this order. Afterward, the blade 4 is carried to the cleaning position C in contact with the cleaning brush 2 along the surface of the photosensitive body 1. Then, the residual dust is rubbed off from the surface of the photosensitive body 1 by the blade 4 with respect to an area extending from the cleaning brush 2 to the exposure device side. Therefore, the blade 4 is carried to the retreat position A after the dust sticking on the blade 4 is cleaned by the cleaning brush 2. Thus, the powdery smoke sticking on the surface of the stopped photosensitive body can be surely prevented from being brought to the exposure device side when the photosensitive body is restarted.

Description

[Detailed Description of the Invention] [Summary] Regarding the cleaning mechanism of an image forming apparatus, an object of the present invention is to reliably prevent dust attached to the surface of a photoreceptor that has been stopped from being carried into the exposure apparatus when restarting. A cleaning brush that cleans dust remaining on the surface of the photoreceptor after image transfer in an electrophotographic image forming device, a suction device that sucks up the dust swept from the surface of the photoreceptor by the cleaning brush, and a cleaning brush that cleans the photoreceptor surface with a cleaning brush. A blade that scrapes residual dust from the surface of the photoconductor that has been removed, a blade that moves the blade to a retracted position away from the surface of the photoconductor when the photoconductor is stopped, and a blade that moves the blade to a predetermined position on the photoconductor when the photoconductor is activated. and a blade retracting device for returning the blade to an operating position where it comes into contact with the blade, the blade retracting device cleaning the blade from the operating position after the photoreceptor has stopped due to the end of an image forming cycle. The brush is moved to a cleaning position in contact with the surface of the photoreceptor, and then moved to a retracted position.

Further, after the photoreceptor is stopped at the end of the image forming cycle, it is configured to run in the opposite direction in synchronization with the movement of the blade from the operating position to the cleaning position.

[Industrial application field]

The present invention relates to a cleaning mechanism for an image forming apparatus applied to, for example, a laser printer.

[Conventional technology]

Generally, in an image forming apparatus that applies electrophotographic theory, a drum-shaped photoreceptor is rotated, a latent image is formed on the surface of the photoreceptor by an exposure device at a predetermined position, and a latent image is formed on the surface of the photoreceptor at another predetermined position by a developing device. Develop the image by attaching toner to the latent image,
Furthermore, the image forming apparatus is configured to transfer an image (toner image) developed at another position onto a sheet of paper using a transfer device. Approximately 5 to 20% of toner remains on the surface of the photoreceptor after transfer, and paper powder may adhere for some reason. If such dust such as toner, paper dust, etc. is carried over to the next cycle, the dust will interfere with the exposure at the stage of exposing the photoreceptor to form a latent image, and a portion of the latent image will not be formed. In addition, dust other than toner, such as paper powder, rubs against the developer during the development stage and causes a negative effect of triboelectric charging on the toner, or enters the developing device and causes a malfunction. . In particular, when forming a color image, dust gets mixed into toners of different colors during the development stage, impairing color reproducibility.

For this reason, conventional image forming apparatuses are provided with a cleaning mechanism that removes dust remaining on the surface of the photoreceptor after transfer.

For example, a cleaning mechanism of a conventional image forming apparatus has a fifth cleaning mechanism.
As shown in the figure, after the toner image is electrostatically transferred to the paper, a cleaning brush 2 is brought into contact with the surface of the photoreceptor 1 at a predetermined cleaning position, and by rotating the cleaning brush 2, the toner image remains on the surface of the photoreceptor 1. The dust swept from the surface of the photoreceptor 1 by the cleaning brush 2 is suctioned by the suction device 3 to remove the dust remaining on the surface of the photoreceptor 1. In order to remove dust that remains after cleaning the photoreceptor 1 with the cleaning brush 2, a blade 4 made of rubber such as polyurethane is placed at a predetermined wiping position on the lower side in the rotational direction of the photoreceptor 1 than the cleaning position. in contact with the surface of the photoreceptor l,
It is configured to scrape off residual dust on the surface of the photoreceptor 1.

In this case, if the blade 4 is fixedly installed, the contact between the photoreceptor l and the blade 4 may become impossible due to wear of the blade 4, or the contact between the surface of the photoreceptor l and the blade 4 may occur due to creep (sagging) of the blade 4. In addition, while the photoconductor 1 is stopped for a long period of time, the surface of the photoconductor 1 that comes into contact with the blade 4 may locally deteriorate, or the tip of the blade 4 may deteriorate. It is known that there are problems such as adhesion to the photoreceptor 1, which may leave scratches on the surface of the photoreceptor 1 that adversely affect image formation.

Conventionally, in order to solve these problems, a blade retracting device 25 is provided to move the blade 4 to a retracted position away from the surface of the photoreceptor 1 while the photoreceptor 1 is stopped. When restarting, move the blade 4 to the photoconductor l.
The device is configured to return to a predetermined operating position in contact with the surface of the device.

In this case, the cleaning mechanism includes a simple retraction type cleaning mechanism that keeps the photoreceptor 1 stopped in response to the retraction of the blade 4, and a cleaning mechanism that contacts the blade 4 of the photoreceptor 1 when the blade 4 is retracted. The cleaning mechanism can be classified into a photoconductor reversal type cleaning mechanism that moves the previously used parts back to the cleaning position.
A reversal priority type that reverses the photoreceptor l before retracting the
It can be classified into a retraction priority type in which the photoreceptor 1 is reversed after the blade 4 is retracted.

[Problem to be solved by the invention]

In the simple retraction type cleaning mechanism, when the photoreceptor 1 is restarted, rotation of the photoreceptor 1 and movement of the blade 4 from the retraction position to the working position are started simultaneously. Therefore, before the blade 4 returns to the working position, the photoreceptor 1
A portion of the surface of the photoreceptor 1 where the residual dust has not been scraped off by the blade 4 passes through the contact position with the blade 4 and moves toward the exposure device, and the residual dust on the surface of the photoreceptor 1 is brought into the exposure device. become. In addition, the blade 4 may be left with a portion of the scraped dust attached to the tip of the blade 4.
is moved to the retracted position, and the blade 4 moved to the retracted position
There is also the problem that, due to mechanical vibrations, dust falls and adheres to the dust-free surface area of the photoreceptor l on the exposure apparatus side, rather than the area that will be next contacted by the blade 4, and is brought into the exposure apparatus.

In a photoconductor reversal type cleaning mechanism, when image formation is completed and the photoconductor 1 is stopped, dust remaining on the surface of the photoconductor 1 between the cleaning brush 2 and the blade 4 causes the photoconductor 1 to reverse. This will cause it to be cleaned again with the cleaning brush.

However, in the case of a reversal priority/photoreceptor reversal type cleaning mechanism, the blade is attached to the surface portion of the photoreceptor l that is moved backward between the contact position with the blade 4 and the contact point with the cleaning brush 2 due to this reversal. The dust dammed up by the blade 4 is dispersed, or a portion of the dust attached to the blade 4 is rubbed against the surface of the photoreceptor 1.

The amount of dust adhering to this part is compared to the amount of dust adhering to the surface of the photoreceptor 1 between the contact position with the blade 4 and the contact position with the cleaning brush 2 in a simple retraction type cleaning mechanism. Although it is small, there remains some dissatisfaction in that it is not possible to reliably prevent residual dust from being scraped off by the blade 4 and brought into the exposure device at the start of the next image forming cycle, so-called dust carryover.

On the other hand, in the case of the evacuation priority/photoreceptor reversal type cleaning mechanism, the dust that has been blocked by the blade 4 is sent back to the cleaning brush 2 position and removed without being dispersed. Most of the dust that falls from the blade 4 when removing the cleaning brush 2
It is sent back to the position and removed. Therefore, photoreceptor 1
When the reversal of the cleaning brush 2 is stopped, a dust-free surface area from which dust has been previously removed by the blade 4 spreads between the contact position with the blade 4 and the contact position with the cleaning brush 2. Therefore, by making the distance between the contact position of the blade 4 and the contact position of the cleaning brush 2 sufficiently large, the dust-free surface area of the photoreceptor 1 that starts rotating at the start of the next image forming cycle can be removed. The blade 4 can be brought into contact with the photoreceptor 1, and dust can be prevented from passing through the blade 4 and being carried into the exposure apparatus.

However, whether it is a reversal priority type or an evacuation priority type,
Even in a photoconductor reversal type cleaning mechanism, the dust falls from the retracted blade 4 onto a dust-free surface area of the photoconductor 1 that is closer to the exposure device than the area where the blade 4 will next contact.
Unable to prevent so-called dust spillage,
This is still unsatisfactory in terms of preventing residual dust from entering the exposure device.

The present invention has been made in view of the above circumstances, and
An object of the present invention is to provide a cleaning mechanism for an image forming apparatus that can reliably prevent dust attached to the surface of a stopped photoreceptor from being carried into an exposure apparatus when restarting.

[Means to solve the problem]

For example, as shown in FIG. 1, the present invention includes a cleaning brush 2 for cleaning dust remaining on the surface of a photoreceptor 1 after image transfer in an image forming apparatus applying electrophotographic theory; a suction device 3 that suctions dust swept from the surface of the cleaning brush 2;
A blade 4 scrapes residual dust off the surface of the photoconductor 1 that has been cleaned with
while moving it to a retreat position A spaced M away from the surface of the
A blade retraction device 5 that returns the blade 4 to an operating position B where it contacts the photoreceptor 1 at a predetermined position when the photoreceptor 1 is activated.
In order to achieve the above object, the following measures are taken on the assumption that the cleaning mechanism of the image forming apparatus is equipped with the following.

That is, the blade retracting device 5 moves the blade 4 along the surface of the photoreceptor from the operating position B to the cleaning position C in contact with the cleaning brush 2 after the photoreceptor 1 has stopped due to the end of the image forming cycle. It is configured to move from to the retracted position A.

Further, after the photoreceptor 1 is stopped at the end of the image forming cycle, the blade 4 is moved from the operating position B to the cleaning position C.
It is configured to run in the opposite direction in synchronization with the movement to.

[Effect]

In the present invention, after the surface of the photoreceptor 1 stops rotating in the direction of sequentially following the exposure device, the developing device, the transfer device, and the cleaning mechanism at the end of the image forming cycle, the blade 4 starts cleaning. The cleaning brush 2 is moved along the surface of the photoreceptor 1 to a cleaning position C in contact with the brush 2, and the remaining dust on the surface area of the photoreceptor 1 on the exposure device side is scraped off by the blade 4 from the cleaning brush 2. Then, after the dust adhering to the blade 4 is cleaned by the cleaning brush 2, the blade 4 is moved to the retracted position A.

Further, in the present invention, when the photoreceptor 1 is moved backward in synchronization with the movement of the blade 4 from the operating position B to the cleaning position C, residual dust on the surface portion of the photoreceptor 1 from the cleaning brush 2 to the blade 4 can be removed. is cleaning brush 2 again.
In addition, when the reverse movement of the photoreceptor 1 is stopped, the dust-free surface area of the photoreceptor 1 that has already been scraped off by the blade 4 is located on the forward side from the cleaning brush 2 at the position of the cleaning brush 2. is reversed until. Moreover, the dust attached to the blade 4 is carried as it is to the position of the cleaning brush 2 together with the blade 4, is swept out by the cleaning brush 2, is sucked into the suction device 3, and is removed from the photoreceptor 1 and the blade 4. After that, the blade 4, which has been cleaned and becomes dust-free, is moved to the retracted position A.
will be moved to

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a longitudinal sectional side view of the cleaning mechanism of the image forming apparatus for a laser printer according to an embodiment of the present invention;
The figure is a plan view thereof, and FIG. 4 is a front view thereof.

This cleaning mechanism includes a cleaning brush 2 that is in rolling contact with the upper outer circumferential surface of the photoreceptor l;
a suction device 3 that sucks dust swept from the surface of the photoreceptor 10 and sends it to a filter device; and a cleaning brush 2.
The blade 4 contacts the surface of the photoconductor I in the forward direction.
and a blade retraction device 5.

The cleaning brush 2 is also called a fur brush because it has a fur-like surface with densely packed flexible bristles, and it continuously cleans the photoreceptor 1 from the start of forward rotation until a predetermined period of time has elapsed after the photoreceptor 1 stops rotating. It rotates in the same direction as the body 1 and cleans the surface of the photoreceptor 1.

The suction device 3 has a cleaning brush 2 above the photoreceptor 1.
a suction duct 31 that covers the
2, and an intake fan 33 provided in the middle of the guide duct 32, and the intake fan 33 is continuously operated from the start of rotation of the cleaning brush 2 until a predetermined period of time has elapsed after the rotation of the cleaning brush 2 ends.

The blade 4 is made of, for example, synthetic resin such as polyurethane, rubber, or the like, and is formed into a long strip in the direction of the rotation axis of the photoreceptor 1 (in the figure, the front and back directions of the page).

The blade retraction device 5 includes a frame 51, a blade holder 52 that holds the base end of the blade 4, and a frame 51.
The blade holder 52 can be moved within a predetermined range in the vertical direction (top of the same figure, vertical direction) and the front-back direction (top of the same figure, horizontal direction), and the blade holder 52 can be returned to a predetermined standby position. It is provided with a suspension spring mechanism 53 for suspending the device. The blade retraction device 5 also includes a solenoid 54a that drives the blade holder 52 rearward (upper left in the figure) and a solenoid 54a that drives the blade holder 52 downward (lower in the upper figure).
The blade holder 52 includes a solenoid 54b that is driven to move the blade holder 52, and a guide mechanism 55 that guides the movement of the blade holder 52.

The suspension spring mechanism 53 is, for example, as shown in FIG.
It is also possible to configure it with a return spring 53a that biases the blade holder 52 upward and a return spring 53b that biases the blade holder 52 backward.

However, this embodiment simplifies the configuration and
In order to maintain the blade holder 52 and the blade 4 supported therein in a constant posture by moving the blade holder 52 in parallel in the vertical direction and the front-back direction, the blade holder 5
The suspension spring mechanism 53 is constituted by four return springs that connect the front and rear parts of the frame 1.51 to the frame 1.51 at two locations on the left and right at appropriate intervals.

The guide mechanism 55 includes a pair of upper and lower pins 55a connected to the blade holder 52, and a pair of upper and lower cam holes 55b formed in the frame 51 corresponding to each pin 55a. The upper side of the peripheral surface of each cam hole 55b is horizontal,
A substantially trapezoidal guide cam surface 55c with a front side shorter than a rear side and an inclined lower side is configured. The lower side may be formed in a straight line, but here it is formed in a curved line parallel to the surface of the photoreceptor 1 so as not to change the contact pressure of the blade 4 to the photoreceptor 1. Then, in response to the movement of the blade 4 from the retracted position A to the operating position B to the cleaning position C to the raised position and to the retracted position A, the pin 55a moves toward the guide cam surface 55.
It is designed to move along c. In addition, the guide cam surface 55 corresponding to each position A, B, C, D of the blade 4
The same reference numerals are given to predetermined positions of c.

This cleaning mechanism is started at the same time as the forward rotation of the photoreceptor 1 (clockwise rotation in FIG. 2) is started at the start of the image forming cycle.

That is, simultaneously with the start of the forward rotation of the photoreceptor 1, the rotation of the cleaning brush 2 is started and the suction fan 33 of the suction device 3 is started, while the solenoid 54b of the blade retraction device 5 is operated to remove the blade. The tip of the blade 4 is brought into contact with the surface of the photoreceptor 1 by moving the blade 4 from a retracted position A shown by an imaginary line in FIG. 2 to an operating position B shown by a solid line in the same figure. Here, the blade 4 is brought into contact with the photoreceptor 1 from a position on the forward rotation side from the position where the photoreceptor 1 contacts the cleaning brush 2 at the time of startup.

During an imaging cycle, photoreceptor 1 continuously rotates in a forward direction, with each point on its surface passing through an exposure device, a development device, a transfer device, and a cleaning mechanism in turn.

In the cleaning mechanism, a cleaning brush 2 sweeps out dust such as toner paper dust remaining on the surface of the photoreceptor l, and a suction device 3 sucks dust such as toner paper dust remaining on the surface of the photoreceptor l, and the filter device sends it to the filter device. Sent. Dust remaining on the surface of the photoreceptor 1 after cleaning with the cleaning brush 2 is scraped off with the blade 5.
Most of it is suctioned by the suction device 3 and removed from the photoreceptor 1 and the blade 4, and a small portion of the remaining portion is held up by the blade 4 and slides on the surface of the photoreceptor 1 or adheres to the blade 4.

At the end of the image forming cycle, first, the forward rotation of the photoreceptor 1 is stopped. Thereafter, the solenoid 54a of the blade retracting device 5 is activated to move the blade 4 from the operating position B to the cleaning position C shown by the imaginary line in FIG. Rotate it in the opposite direction so that it accompanies you. As a result, when the photoconductor 1 stops moving forward, the dust remaining on the surface of the photoconductor 1 between the cleaning brush 2 and the blade 4 and the dust attached to at least the tip of the blade 4 are removed by the cleaning brush. 2, and is suctioned and removed by a suction device 3. Then, between the operating position B of the blade 4 and the cleaning position C, the dust-free surface area of the photoreceptor 1 that was cleaned by the blade 4 during the previous image forming cycle moves backward. After this, the solenoid 54b of the blade retraction device 5
The blade 4 is moved to the raised position shown by the imaginary line in FIG. 2 above the cleaning position C by the elastic restoring force of the suspension spring mechanism 53, and then the blade retracting device 5
By stopping the operation of the solenoid 54a, the suspension spring mechanism 53 is elastically restored and the blade 4 is returned to the retracted position A shown in FIG. Retreat position? Since at least the tip of the blade 4 returned to &A has been cleaned by the cleaning brush 2 and is dust-free, the blade 4 that has been returned to the retracted position iA will be removed from the blade 4 on the surface of the photoreceptor I in the next image forming cycle. There is no fear that dust will fall to the exposure device side beyond the position where 4 starts to make contact.

Also, when the next image forming cycle is started, the cleaning brush 2 is removed when the previous image forming cycle was stopped.
Since the blade 4 comes into contact with the dust-free surface 6N that has been moved backwards to the position , the dust adhering to the surface of the photoreceptor 10 passes under the blade 4 and moves to the exposure apparatus side, so-called dust carryover occurs. It is possible to reliably prevent dust from being brought into the exposure device due to carryover.

In the above embodiment, the blade 4 is configured to move in parallel on a trapezoidal trajectory along the guide cam surface 55c.
In the present invention, the blade 4 moves from the operating position B to the cleaning position C while maintaining contact with the surface of the photoreceptor l,
Here, after being cleaned with the cleaning brush 2, the photoconductor l
It suffices if the structure is such that it moves to the retracted position A away from the surface. For example, by simultaneously stopping the operation of the solenoid 54a and the solenoid 54b after cleaning at the cleaning position C, it is possible to control M so as to return from the cleaning position C to the retracted position A without going through the raised position. It is.

Further, in the above embodiment, when the blade 4 moves from the operating position B to the cleaning position C, the photoreceptor 1 is rotated in the opposite direction to match the moving direction of the blade 4. may be stopped. In this case, as the blade 4 moves from the operating position B to the cleaning position C, the remaining dust on the surface of the photoreceptor 1 during this period is scraped off by the blade 4, and this surface becomes dust-free. It is possible to obtain the same effect as in the first embodiment.

〔Effect of the invention〕

As described above, according to the present invention, at the end of an image forming cycle, the blade is moved to the cleaning brush position while keeping it in contact with the photoreceptor, and the blade is moved in synchronization with the direction of the cleaning brush. The photoreceptor is moved in the opposite direction, and the dust-free surface area on the exposure device side than the blade is moved backwards to the cleaning brush position.
Alternatively, you can move the blade to the cleaning brush position while keeping it in contact with the photoreceptor, and while the blade is moving, the blade will scrape away the dust on the surface of the photoreceptor, leaving the surface dust-free. At the beginning of the imaging cycle, the blade can be brought into contact with the surface of the photoreceptor from within a dust-free surface area, and any residual dust that has settled on the photoreceptor before the blade makes contact is removed from the exposure device by the point where the blade makes contact. It is possible to reliably prevent the so-called carryover of dust that is carried to the side, and it is possible to reliably prevent dust from being brought into the exposure apparatus due to carryover of dust.

In addition, at the end of the image forming cycle, the blade is moved to the cleaning brush position, cleaned with the cleaning brush, and then returned to the retracted position, so dust can be removed from the blade that has retreated to the retracted position due to mechanical vibration, etc., and the image formation is completed. There is no risk of so-called dust spillage occurring when the blade falls onto the dust-free surface area cleaned during the cycle (this also reliably prevents dust from being carried into the exposure apparatus due to dust spillage).

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of the present invention, FIG. 2 is a vertical sectional side view of a cleaning mechanism of an image forming apparatus for a laser printer according to an embodiment of the present invention, and FIG. 3 is a plan view thereof. FIG. 4 is a front view thereof, and FIG. 5 is a longitudinal sectional side view of the conventional example. In the figure, 1...photoreceptor, 2...cleaning brush, 3...suction device, 4...blade, 5...blade retraction device.

Claims (1)

[Scope of Claims] [1] A cleaning brush (2) for cleaning dust remaining on the surface of the photoreceptor (1) after image transfer in an electrophotographic image forming apparatus;
1) A suction device (
3) - and a blade (4) that scrapes residual dust from the surface of the photoreceptor (1) that has been cleaned with the cleaning brush (2).
Then, while the photoconductor (1) is stopped, move the blade (4) to the photoconductor (
1) to a retracted position (A) away from the surface of the photoreceptor (1), and return it to an operating position (B) where the blade (4) contacts the photoreceptor (1) at a predetermined position when the photoreceptor (1) is activated. In the cleaning mechanism of the image forming apparatus, the blade retracting device (5) moves the blade (4) above after the photoreceptor (1) stops due to the end of the image forming cycle. The cleaning brush (2) is moved from the operating position (B) to the cleaning position (C) in contact with the cleaning brush (2) while remaining in contact with the surface of the photoreceptor (1), and then moved to the retracted position (A). A cleaning mechanism for image forming apparatuses. [2] After the photoreceptor (1) is stopped at the end of the image forming cycle, it runs in the opposite direction in synchronization with the movement of the blade (4) from the operating position (B) to the cleaning position (C). The cleaning mechanism for an image forming apparatus according to claim 1, wherein the cleaning mechanism is configured to perform cleaning.