JPH08137208A - Cleaning device for electrifying roller in image forming device - Google Patents

Abstract

PURPOSE: To surely remove a foreign matter from the surface of an electrifying roller and to stably secure uniform electrification for a long time by disposing a cleaning material rubbing the surface of the electrifying roller in the rotating direction and the axial direction of the electrifying roller. CONSTITUTION: A cleaning member is constituted of a supporting body 11 extending in the axial direction of the electrifying roller and the cleaning material 12 wound round the supporting body 11, and is rotated by a driving motor through a gear so as to rub and clean the surface of the electrifying roller 3. The cleaning member is arranged on the surface of the roller 3 so that abutting pressure may be uniform nearly over the entire length in the axial direction. In this case, when the cleaning material 12 is relatively rotated to an image carrier 2, the surface of the cleaning material 12 rubs the surface of the image carrier in a circumferential direction and also in the axial direction, because the cleaning material 12 is wound round in a spiral state. Therefore, the rubbing part of the cleaning material 12 to the image carrier successively arrives at the position of the foreign matter 6, so that the foreign matter 6 is removed.

Description

Detailed Description of the Invention

[0001]

[Object of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrostatic copying machine and a printer, and more particularly to a cleaning device for a charging roller used as a charging means.

[0002]

2. Description of the Related Art In the known image forming apparatus as described above, the surface of the image carrier is uniformly charged prior to image formation. As a charging means therefor, the image carrier is used. A device using a charging member that is in contact with the above has already been proposed, for example, as disclosed in Japanese Patent Laid-Open No. 63-167380.

It has been recognized that such a contact charging means has advantages that a lower applied voltage can be used and less ozone and nitrogen oxides are generated, as compared with a corona discharger which has been frequently used. .

On the other hand, this type of contact charging means is liable to attach various foreign substances such as paper powder, dust, and floating toner in the apparatus during use, which tends to cause irregular charging and further deterioration of image quality. . In order to avoid such problems,
A cleaning device for charging means is disclosed, for example, in Japanese Patent Laid-Open No. 3-1.
It is disclosed in Japanese Patent Publication No. 01768.

Such a known cleaning device will be briefly described with reference to FIG. This figure is a side view showing only the rotating cylindrical image carrier 2 arranged in the image forming apparatus and a portion of the charging roller 3 that is in contact with the image carrier 2. The charging roller 3 is driven and rotated by the rotational driving of the image carrier 2. It shall be.

The charging roller 3 is in contact with a cleaning pad 1 extending in the axial direction and made of polyurethane foam or the like. Since the cleaning member 1 is fixed at a fixed position in the image forming apparatus, the surface of the charging roller 3 is cleaned by rubbing when the charging roller 3 rotates.

At the same time, such a cleaning means can be repeatedly used for a long time (hereinafter referred to as "durability").
The cleaning function deteriorates due to clogging, and at this time, foreign matter that has slipped through the cleaning pad 1 is charged by the charging roller 3.
The stripes adhere to and adhere to the surface of the image carrier, which causes stripe-shaped uneven charging on the surface of the image carrier, which causes vertical stripe-shaped image defects.

The present invention has been made in order to cope with such a situation, and is an image forming apparatus provided with a contact type charging means that comes into contact with an image carrier, and is stable and good for a long period of time. It is an object of the present invention to provide a cleaning means capable of performing cleaning.

[0009]

Configuration of the Invention

In order to achieve the above object, the present invention has an image carrier and a charging roller that abuts against the image carrier, and abuts on the charging roller and rubs the surface thereof. An image forming apparatus having cleaning means for cleaning, wherein the cleaning means comprises a spiral elastic member extending in the axial direction of the charging roller and contacting the surface of the roller,
Alternatively, in the above, the cleaning device for a charging roller is characterized in that the cleaning means is configured in a belt shape made of an elastic material that extends in contact with the surface axis of the charging roller and travels in the direction.

According to this structure, it is impossible to prevent solidification of foreign matter adhering to the charging roller and to always perform stable charging.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention. Only an image carrier 2 of an image forming apparatus, a charging roller 3 abutting on the image carrier 2 and a cleaning member abutting on the charging roller 3 are shown. Is shown.

The cleaning member is composed of a support 11 extending in the axial direction of the charging roller and a cleaning material 12 which will be described later and wound around the support, and is rotated by a drive motor 5 via gears 42 and 41 to be charged. The surface of the roller 3 is rubbed and cleaned.

The support 11 is a cylindrical body made of a rigid material having a diameter of about 2 to 10 mm, and the cleaning material 12 has a width of 2 to 2.
0 mm, preferably 3-10 mm, thickness 1-10 m
m, preferably 2 to 5 mm of elastic material.

As the cleaning material, foamed polyurethane, foamed silicone, foamed styrene butadiene rubber, foamed ethylene propylene rubber, foamed butyl rubber, foamed natural rubber, foamed isoprene rubber, foamed butadiene rubber, foamed chloroprene rubber, foamed acrylonitrile butadiene rubber, foamed. It can be selected and used from fluororubber, artificial leather, non-woven fabric and the like.

The cross-sectional shape of the cleaning material 12 may be rectangular, but may be trapezoidal, triangular, semicircular, or an appropriate curved shape in order to reduce the frictional force with the charging roller 3. Further, the cleaning material 12 forms an angle of less than 90 degrees with respect to the surface running direction of the charging roller 3, preferably 10 to 80.
The angle is 1 to 30 mm, preferably,
It is wound and fixed on the support 11 with a thickness of 3 to 20 mm. Such a cleaning member is arranged on the surface of the charging roller 3 so that the contact pressure is uniform over the entire length in the axial direction.

The support 11 is driven by the motor 5 via the gears 41 and 42, and the peripheral speed of the cleaning material 12 at this time is 10 to 300% of the peripheral speed of the charging roller 3.
(Excluding 100%), preferably 50 to 200% (1
(Excluding 00%) is preferable. Further, the rotation direction of the cleaning material 12 may be either forward or reverse to that of the charging roller.

Next, the function of removing foreign matter on the charging roller by the above cleaning device will be described with reference to FIG. The same figure is a partial enlarged view showing the relational arrangement between the charging roller 3 and the cleaning material 12 that contacts the charging roller 3.

When the cleaning material 12 is rotated relative to the image carrier 2, since the cleaning material 12 is spirally wound, its surface rubs the surface of the image carrier 2 in the circumferential direction. At the same time, it also rubs in the axial direction.

Therefore, even if there is a foreign substance 6 that has slipped through the cleaning material 12 at a certain position, the foreign substance 6 will not be present at the position of this foreign substance 6.
Since the portion of the cleaning material 12 that is rubbed against the image carrier sequentially arrives, a force to remove the cleaning material 12 is applied each time, and the action of adhering to the image carrier weakens. Move in the direction and be removed later,
Furthermore, the image is conveyed outside the image area and does not adversely affect the image formation.

The cleaning device as described above is applied to a known printer using a process cartridge.
The results of printing 000 sheets are shown in Table 1 in comparison with the case where a known fixing type cleaning means is used. As can be seen from the table above, when the fixed cleaning material is used, the foreign matter that has slipped through the cleaning material begins to adhere to the surface of the image carrier after 4000 sheets have passed, and the deterioration of the image quality due to the charging failure is caused by this. Appearing, the image quality after passing 6000 sheets became unusable.

On the other hand, when the apparatus according to the embodiment of the present invention is used, the cleaning acts not only in the circumferential direction of the charging roller but also in the axial direction. Since there was no adherence of particles and uniform charging was maintained, no deterioration in image quality was observed even when 6,000 sheets were passed.

FIG. 3 is a front view of essential parts showing another embodiment of the present invention, and FIG. 4 is a plan view. In the figure, the image carrier 2,
Only the charging roller 3 and the cleaning device portion of the charging roller which are in contact with this are shown.

The charging roller 3 contacting the image carrier 2 has
The cleaning material 12 attached to the belt 132 is in contact. The belt 13 is suspended by gears 43 and 44, and has a length such that the cleaning material 12 attached to the belt 13 covers the entire image area in the axial direction of the charging roller 3.

The gear 43 is connected to the motor 5 via the gear 42, and the belt 13 and hence the cleaning material 12 travels in the left-right direction in the figure by the motor 42 so that the surface of the charging roller 3 is rubbed and cleaned. become.

The width of the belt 13 can be appropriately set within the range of 2 to 15 mm. The width of the cleaning material 12 is the belt 13
The same material and cross-sectional shape as those of the cleaning material in the above-described embodiment can be used. In this device, the speed of the portion of the cleaning material 12 that contacts the charging roller is 1 to 60 mm / sec, preferably 2
-30 mm / sec is preferable.

FIG. 5 is a partially enlarged view for explaining the operation of this device. Since the surface of the charging roller is running around the axis of the charging roller 3 extending parallel to the paper surface, and the cleaning material 12 is running in the direction parallel to the paper surface, the foreign matter 6 on the charging roller 3 is charged to the charging roller 3. The rubbing action in both the circumferential direction and the axial direction will be added.

Therefore, the foreign matter 6 on the charging roller, which has once slipped through the cleaning material 12, is also captured again at the next rubbing, or is moved in the axial direction of the charging roller and discharged to the outside of the image area and slipped through. It is possible to preferably avoid a situation in which the foreign matter 6 stagnant and solidifies on the surface of the charging roller and adversely affects the image quality.

Table 2 below shows a comparison between the apparatus of the above-described embodiment and the case where the same printer is used and a known fixing type cleaning material is used. As can be seen immediately from this table, it was confirmed that according to the apparatus of this embodiment, even when 6000 sheets were passed, no streak-like foreign matter adhered and solidified on the charging roller, and the image quality did not deteriorate.

As described above, according to the present invention,
When cleaning the charging roller that is in contact with the image carrier of the image forming apparatus, by disposing a cleaning material that rubs the roller surface in both the rotation direction and the axial direction of the charging roller, The foreign matter can be reliably removed, stable and uniform charging can be secured for a long period of time, and it contributes largely to obtaining a high-quality image.

[Brief description of drawings]

FIG. 1 is a front view of a main part of a charging roller cleaning device according to an embodiment of the present invention.

[Fig. 2] Same as above

FIG. 3 is a front view of a main part of a cleaning device according to another embodiment.

FIG. 4 Same as above

[Fig. 5] Same as above

FIG. 6 is an explanatory view showing a known charging roller cleaning device.

[Explanation of symbols]

 1 Cleaning Pad 2 Image Carrier 3 Charging Roller 5 Motor 11 Support 12 Cleaning Material 13 Belt 41, 42, 43, 44 Gear 6 Foreign Material

Claims (2)

[Claims] 1. An image forming apparatus, comprising: an image carrier and a charging roller that abuts against the image carrier; and an image forming apparatus including a cleaning unit that abuts on the charging roller and cleans the surface thereof by rubbing. A cleaning device for a charging roller, comprising a spiral elastic member extending in the axial direction of the roller and contacting the surface of the roller. 2. The cleaning device for a charging roller according to claim 1, wherein the cleaning means is formed in a belt shape made of an elastic material that extends in contact with the surface of the charging roller in the axial direction and travels in the direction.