JPH0473787A - Cleaning device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of unevenness in the rotation of an image carrier from occurring and to eliminate irregularity in an image formed on a transfer paper by allowing a cleaning roller only to rotate by following the image carrier in a period from starting image exposure to the image carrier until finishing transfer to a transfer material. CONSTITUTION:Since the cleaning roller 11 only rotates by following the image carrier 2 during the period from starting the image exposure to the image carrier 2 until finishing the image transfer to the transfer material, the uneven rotation of the image carrier 2 does not occur. Meanwhile, the roller 11 has a speed difference from the image carrier 2 in a period except the above period, so that the surface of the image carrier 2 corresponding to the period is forcibly rubbed and cleaned completely by the roller 11. Even though the unevenness occurs in the rotation of the image carrier at such a time, there is no effect on the image formed on the transfer material because the transfer is finished.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cleaning roller used in an image forming apparatus, and more particularly, to an improvement in a cleaning roller provided with a cleaning roller.

(Prior art) Conventionally, a cleaning roller was equipped with a rotatable leaning roller that was in pressure contact with the surface of an image carrier, and used as a cleaning roller to remove toner remaining on the image carrier after transfer. (Refer to Japanese Unexamined Patent Application Publication No. 60-33582); ■ A method in which the cleaning roller is forcibly rotated at a speed different from the moving speed of the image carrier surface. However, in the cleaning roller of (1) above, the frictional force between the image carrier and the cleaning roller is small. For this reason, residual toner that has fused and solidified on the image carrier, paper dust, filler in the paper powder (talc, kaori, etc.), or discharge generated on the image carrier due to corona discharge from the charging charger or transfer charger. Products etc. remain without being removed.

(Hereinafter, these are collectively referred to as residual toner, etc.) And,
As a series of image forming operations is repeated, residual toner and the like that remain without being removed accumulate on the image carrier, and the image is smudged by this residual toner and the like.

On the other hand, in the above cleaning roller (2), since the cleaning roller has a speed difference with respect to the image carrier being driven, the frictional force between the image carrier and the cleaning roller is large. Therefore, residual toner and the like on the image carrier are also removed. However, since the frictional force acts as resistance to the rotation of the image bearing member, it causes uneven rotation of the image bearing member, and this rotational unevenness has an adverse effect on the image. The density of the formed image may become uneven.

To solve this problem, it is conceivable that the surface of the roller be made of a material with a small coefficient of friction so that the frictional force between the image carrier and the cleaning roller does not become large. However, it is difficult to select a material that can ensure cleanability and provide a frictional force that does not create resistance to the rotation of the image carrier.

In view of the above problems, it is an object of the present invention to provide a cleaning roller that can sufficiently clean an image carrier without causing image disturbance due to uneven rotation of the image carrier even when the cleaning roller is used. purpose.

(Means for Solving the Problems) In order to achieve the above object, the present invention exposes an image on an image bearing member which is negatively charged and is driven to rotate to form an electrostatic latent image. In a cleaning roller used in an image forming apparatus that converts an image into a toner image and transfers the image,
a cleaning roller that is in pressure contact with the surface of the image carrier and is rotatably supported; during an image forming operation;
The cleaning roller is driven by the image bearing member at least during a period from the start of image exposure to the image bearing member until the transfer of the toner image is completed. The present invention is characterized in that it includes a drive switching means that provides a speed difference to the carrier.

(Function) During the period from the start of image exposure to the image carrier until the end of image transfer to the transfer material, the cleaning roller only rotates following the image carrier, so uneven rotation of the image carrier occurs. do not.

On the other hand, during periods other than the above period, the cleaning roller has a speed difference with respect to the image bearing member, so the surface of the image bearing member corresponding to this period is forcibly rubbed by the cleaning roller and is sufficiently cleaned. At this time, even if unevenness occurs in the rotation of the image carrier, it will not affect the image formed on the transfer material because it is after the transfer has been completed.

(Example) Next, an example of the cleaning roller according to the present invention will be described using the drawings.

FIG. 2 is a schematic cross-sectional view showing the main parts of an image forming apparatus using a cleaning roller (1).

First, the photoreceptor (2) from which the residual potential has been removed by the eraser run (3) is charged in a negative manner by the charger (4), and then a light image (5) corresponding to the image information is irradiated. An electrostatic latent image is formed. This electrostatic latent image is then visualized by toner supplied by a developing device (6). This toner image is transferred by a transfer charger (8) onto a transfer material (30) which is conveyed by a timing roller (7). After that, the transfer material is transferred to a separate charger (9
) is separated from the photoreceptor (2) by a conveyor belt (10
) is transferred to the next process.

On the other hand, the toner remaining on the photoconductor (2) without being transferred in the transfer process is removed by the cleaning roller (1) together with foreign matter such as paper dust, and the photoconductor (2) is prepared for the next copying process. .

Next, the configuration of the cleaning roller (1) will be explained using FIGS. 1 and 2.

FIG. 1 is a perspective view schematically showing a cleaning roller (]).

The cleaning roller (1) generally includes a cleaning blade (21), a cleaning roller (11), and a toner collection section (28).

The cleaning blade (21) is held by a blade holder (22) on the side that does not come into contact with the photoreceptor (2), and the blade holder (22) is attached to a shaft (2) provided on the frame (15).
The holder holder (19
) is maintained.

A lever (27) is provided on the upper surface of the holder holder (19) at the center in the longitudinal direction. The other end of a tension spring (16) fixed to the rear toner collection section (28) is fixed to the note bar (27), and the lever (27) is attached downward by this tension spring (16). Forced. With the above configuration, the cleaning blade (21) is brought into pressure contact with the photoreceptor (2).

On the other hand, the cleaning roller (11) has its rotating shaft (1
2) is rotatably supported around support shafts (26), (26) and supported at the ends of a pair of roller pressing members (18) (18). The roller pressure contact member (18), (
A spring (17), (17) whose one end is fixed to the frame body (15) is connected to the other end of 18), and this pie (17), (17) is a roller pressure contact member. (18),
(18) is biased clockwise in FIG. 2 in the direction of rotation. With the above configuration, the cleaning roller (11) is brought into pressure contact with the photoreceptor (2). A gear (23) is fixed to one end of the rotating shaft (12) of the cleaning roller (11).
is engaged with a gear (25) fixed to the output shaft of a clutch (24) serving as drive switching means.

A scraper (13) for scraping off toner adhering to the cleaning roller (11) is in pressure contact with the side of the cleaning roller (11) opposite to the side that comes into contact with the photoreceptor (2). A toner collecting section (28) is provided on the opposite side of the cleaning roller (11) across the scraper (13), and the toner scraped by the scraper (28) is collected by the toner collecting section (28). Ru. This toner collecting section (28) is hollow and has an opening (29) formed in a portion facing the scraper (13).

In addition, a frame body (15) is provided in the hollow part of the toner collection section (28).
A recovery spiral (14) is rotatably supported by the retrieval spiral (14).

Next, the operation of the cleaning roller (1) will be explained using the time chart shown in FIG. Here, clutch ON represents the connected state of the clutch (24), and clutch O
FF represents a disconnected state of the clutch (24).

First, according to the time flow in Figure 3, the clutch (24)
Explain the timing to intermittent.

(i) The image forming apparatus is powered on, warm-up of the fixing device (not shown) is completed, and the clutch (24) is connected at the timing when a warm-up completion signal is output from the CPU (not shown).

Thereafter, after the photoreceptor (2) has preliminarily rotated for a predetermined period of time, the clutch (24) is disconnected at the same time as the photoreceptor (2) stops.

(i) A print switch (not shown) is turned on and the clutch (24
) is connected, and the photoreceptor (2) starts rotating.

Thereafter, the clutch (24) is disconnected at the timing when exposure of the photoreceptor (2) is started.

(ii) After the transfer of the image to the transfer material is completed, the clutch (24) is connected at the timing when the rear end of both images passes the position facing the cleaning roller (l l), and then the photoreceptor (2) At the same time as the clutch (24) stops,
is cut off.

(iv) When performing continuous image formation, after the previous transfer is completed, the clutch (24) is connected at the timing when the trailing edge of the image passes the position facing the cleaning roller (11), and the next exposure is performed. The clutch (24) is disengaged at the timing when this starts.

Next, the cleaning operation of the cleaning roller (1) when the clutch (24) is disconnected and connected will be explained using FIG.

First, when the clutch (24) is in a disengaged state, the gear (25) can rotate freely, so the cleaning roller (11) in pressure contact with the photoreceptor (2) follows the rotation of the photoreceptor (2). and rotate in the direction of arrow A. Then, the photoreceptor (
2) rotates, the photoreceptor (2) and cleaning roller (
A portion of the residual toner passing through the pressure contact portion (11) adheres to the surface of the cleaning roller (11). The toner adhering to the surface of the cleaning roller (l l) is conveyed to the side opposite to the photoreceptor (2) as the cleaning roller (11) rotates, and is scraped off by the scraper (13), leaving the opening (29). It passes through and falls into the toner collection section (2nd cup). The toner in the toner collection section (28) is collected by the cleaning roller (1) by rotation of the collection spiral (14).
) is provided outside the waste toner storage section, and is transported to the waste toner storage section shown in the figure.

Toner remaining on the photoreceptor (2) without being removed by the cleaning roller (l l) is scraped off by the cleaning blade (21). Since the cleaning roller (l l) merely follows the photoreceptor (2) and does not obstruct the rotation of the photoreceptor (2), uneven rotation of the photoreceptor (2) does not occur.

Next, the cleaning operation of the six cleaning rollers (1) in a state where the clutch (24) is connected will be explained.

When the clutch (24) is connected, the rotation of the gear (25) is stopped, and the rotation of the cleaning roller (l l) is also stopped. Therefore, a speed difference occurs between the rotating photoreceptor (2) and the cleaning roller (11), and a frictional force is generated at the pressure contact portion between the two.

This frictional force ensures that the toner passing through the pressure contact portion falls downward. In this way, when the clutch (24) is connected, toner is removed not only by the cleaning blade (2J) but also by the cleaning roller, so the clutch (24)
Toner is removed more effectively than when the toner is disconnected. However, the cleaning roller (
11) and the cleaning blade (21) do not cover the entire area of the photoreceptor (2). However, since the area cleaned by the cleaning roller (11) and cleaning blade (2I) differs for each copying operation, the entire area of the photoreceptor (2) is sufficiently cleaned within a predetermined number of copying operations. . Therefore, toner remaining on the photoreceptor (2) without being cleaned does not accumulate to the extent that it affects the image.

Further, the frictional force acting between the cleaning roller (11) and the photoreceptor (2) acts as resistance to the rotation of the photoreceptor (2), causing uneven rotation of the photoreceptor (2). However, since the clutch (24) is connected during a period other than the period from the start of exposure to the completion of transfer as described above, it does not adversely affect the image formed on the transfer material.

Further, in this embodiment, after the trailing edge of the toner image passes the position facing the cleaning roller (11), the clutch (24)
Since the toner remaining on the image bearing member after transfer is not scraped off by the cleaning roller (11), the toner is transferred to the toner collecting section (28).
) will not fall to any other position.

In the above embodiment, an example was explained in which the cleaning roller is stopped during a period other than the period from the start of exposure to the completion of transfer. The image carrier may be forcibly driven in a direction opposite to the rotational direction of the image carrier. At this time, if the cleaning roller is driven in the opposite direction at the part where it contacts the image carrier, the frictional force increases.
Cleaning is more effective. Further, in the above embodiment, the cleaning roller has a relative speed difference with respect to the image carrier at the timing when the most downstream part of the toner image on the image carrier passes the position facing the cleaning roller. A cleaning roller speed difference may be provided to the image carrier at the timing when the transfer is completed.

In this case, it is necessary to adopt a structure that collects the toner that has been forcibly rubbed and scraped off by the cleaning roller, for example, a structure in which the toner collecting section is disposed below the rough cleaning roller.

Further, in the above embodiment, an example was explained in which the cleaning roller was arranged upstream of the cleaning blade with respect to the rotational direction of the image bearing member, but a cleaning roller in which the cleaning roller was arranged downstream of the cleaning blade, or a cleaning blade The present invention can also be applied to a cleaning roller that does not use a fur brush or a cleaning roller that uses a fur brush. When the cleaning roller is disposed downstream of the cleaning blade, the cleaning roller can effectively remove only residual toner etc. that have not been removed by the cleaning blade.

(Effects of the Invention) The cleaning roller provided in the cleaning roller of the present invention only rotates following the image carrier during the period from the start of image exposure to the image carrier until the completion of transfer to the transfer material. Therefore, uneven rotation of the image carrier does not occur, and the image formed on the transfer paper is not disturbed.

On the other hand, during periods other than the above period, there is a relative speed difference between the cleaning roller and the image carrier, so the image carrier is forcibly rubbed against the cleaning roller, and this rubbing causes the image carrier to be sufficiently Clinic.

[Brief explanation of the drawing]

[No.] U1! :J is a perspective view schematically showing a cleaning roller for carrying out the present invention, FIG. 2 is a schematic cross-sectional view showing main parts of an image forming apparatus using a cleaning roller according to the present invention, and FIG. 3 is a schematic perspective view of a cleaning roller. It is a time chart showing operation timing. 2... Image carrier 11... Cleaning roller 23, 24, 25... Drive means patent applicant Minolta Camera Co., Ltd.

Claims (1)

[Claims] A cleaning device used in an image forming apparatus that exposes an image to a uniformly charged and rotationally driven image carrier to form an electrostatic latent image, and transfers the electrostatic latent image as a toner image. a cleaning roller that is in pressure contact with the surface of the image carrier and is rotatably supported;
During the image forming operation, the cleaning roller is driven by the image carrier at least during the period from the start of image exposure to the image carrier until the transfer of the toner image is completed, while the cleaning roller is driven by the image carrier during the period other than the above period. A cleaning device comprising a drive switching means for causing a cleaning roller to have a speed difference with respect to the image carrier.