JPS613186A - Cleaning device - Google Patents

Abstract

PURPOSE:To obtain a satisfactory cleaning function over a long period by constituting a blade in such a manner that the friction effect thereof has the tendency to balance always on both sides of a revolving shaft for equalization so that the always uniform blade pressure can be exerted to an image carrying body in the transverse direction thereof. CONSTITUTION:The cleaning blade 1 having an equalizing function of a cleaning device consisting of the blade 1 which is brought into press contact with the surface of a traveling photosensitive body is so constituted as to have a sharp angle theta with the plane in contact with the image carrying body in the contact position of the edge of the cleaning blade with the image carrying body. The cleaning blade consisting of an elastic material such as urethane rubber is used as a cleaning means and is applied to a copying machine in which a rotating cylindrical photosensitive body is used. Then the torque acts to eliminate the unbalance in the friction between the cleaning blade and the image carrying body even if such unbalance arises. The function of maintaining uniformly the blade edge in contact with the surface of the image carrying body at all times is thus obtd.

Description

Detailed Description of the Invention (1) Purpose of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus that uses an electrostatic transfer process, such as an electrophotographic copying machine or a printer, and particularly to a cleaning device therefor. .

(Prior art and issues to be solved) Form transferable toner scratches on the surface of an image carrier that runs endlessly, and after transferring this to a transfer material, remove the residual toner remaining on the surface of the image carrier. In well-known image forming apparatuses, as a cleaning means for removing residual toner, a cleaning blade made of an elastic material such as rubber is brought into pressure contact with the surface of an image carrier to scrape off the toner. It is provided.

Various types of such leaning means have already been proposed, and the present invention particularly provides a cleaning blade that is in pressure contact with the image carrier in the width direction, and a cleaning blade that is rotatably pivoted in the longitudinal center portion of the blade. The blade is supported at this pivot position and has an equalize function that presses the blade toward the image carrier to bring the blade into pressure contact with the image carrier surface as uniformly as possible over the entire length. The present invention relates to a cleaning device having a cleaning blade.

Such a known cleaning device will be briefly described with reference to FIGS. 3 and 4.

These figures are schematic side views of the main parts of the above-mentioned leaning device used in a copying machine.
To explain the figure, a housing of a cleaning device (not shown) is arranged close to a predetermined position of the photoreceptor formed in a rotating cylindrical shape, and a blade is supported on a rotating shaft 4 that is pivotally supported in a proper position of the housing. A cleaning blade 1 made of a suitable elastic material such as urethane rubber is attached to a member 3, and one longitudinal edge (perpendicular to the plane of the paper) of the cleaning blade 1 is fixed to this member. is in contact with the photoreceptor 1. Support member 3. The blade 1 and the like are given a rotational tendency in the counterclockwise direction shown in the figure by an appropriate means (not shown) such as a spring double weight in the cleaning device, so that the edge of the blade is pressed against the surface of the photoconductor with a predetermined pressure. are doing.

The area around the photoconductor is the charger, exposure section, and developer.

It goes without saying that members necessary for forming and transferring a toner image, such as a transfer charger, are arranged, but since they are not directly related to the present invention, a description thereof will be omitted.

Rotating shaft 4. The support member 3 supported by this and having the cleaning blade 1 attached thereto is centered around the rotating shaft 4 as shown in the figure.
It rotates within a plane so that the edge of the cleaning blade 1 is pressed as uniformly as possible over its entire length.

If the tangential plane to the photoreceptor J at the part where the edge contacts the surface of the photoreceptor 1 is α, then the angle θ between the planes γ and α is larger than 90. It was normal.

Although FIG. 3 shows a device equipped with so-called counter type blades, the same applies to a device equipped with a forward type blade arrangement. FIG. 4 shows the forward direction, and the parts corresponding to those shown in FIG. , it will be readily understood that the angle θ between the plane γ and the plane α is larger than 90, which is the same as that in FIG.

When the photoreceptor is configured as described above, a component force F1 in the direction of the plane γ acts on the photoreceptor due to the frictional force F applied to the edge of the blade due to pressure contact and sliding between the photoreceptor and the blade.

Therefore, if there is a difference in the frictional force on both sides of the rotating shaft 4 of the cleaning blade that is in pressure contact across the width of the photoreceptor, this will cause an imbalance in the component force F1, and the component force F will be stronger. A torque is generated on the shaft 4 that tends to force the side to be strongly pressed against the photoconductor, and this torque causes an even stronger frictional force to act on the side that is in stronger contact with the photoconductor, increasing the component force F, and promoting the torque. There is a tendency to

This torque converges to a certain value determined by the friction coefficient and the angle θ, but due to an unbalance of blade pressure on both sides of the rotating shaft 4, there is a difference in blade friction. It was not possible to avoid defects that caused defects.

The present invention has been made in view of this situation, and it is possible to reduce the friction of the blade by changing the angle θ mentioned above and determining the arrangement of the cleaning blade with respect to the image carrier. To provide a leaning device which prevents the occurrence of balance and can obtain a good IJ-ning effect.

(2) Structure of the invention (technical means for solving the problem and its operation) In order to achieve the above object, the present invention provides a cleaning device in which a cleaning blade having an equalizing function is pressed against the surface of a traveling photoreceptor. The angle θ formed by the equalizing rotating surface of the blade and the plane tangential to the image carrier at the position where the edge of the cleaning blade contacts the image carrier is an acute angle.

As a result, even if there is an unbalance in the friction between the cleaning blade and the image carrier, the torque is applied to eliminate this imbalance, and the plate edge is constantly brought into uniform contact with the surface of the image carrier. It has many functions.

(Explanation of Embodiment) FIGS. 1 and 2 show an embodiment of the present invention, in which a cleaning blade made of an elastic material such as urethane rubber is used as a cleaning means, as in the case of the above-mentioned known one. The present invention is applied to a copying machine using a rotating cylindrical photoreceptor.

In FIG. 3, reference numeral 2 indicates a charger, an exposure means,
It is a rotating cylindrical photoreceptor that is equipped with image forming and transfer means such as a developing device and a transfer charger (both not shown).A cleaning device is arranged downstream of the transfer position when viewed in the direction of rotation. A support member 3 is fixed to a rotating shaft 4 attached to a rotating shaft 4, one edge of a cleaning blade 1 is attached to this support member, and the other edge is in pressure contact with the surface of the photoreceptor 1. . The supporting member and the cleaning blade are integrally oscillated around the rotating shaft 4 on a plane γ to bring the plate edge into contact with the surface of the photoreceptor to perform an equalizing function.

The plane r intersects the tangential plane α to the photoconductor at an angle θ at the contact portion of the plate edge to the photoconductor,
It is assumed that the direction of the rotating shaft 4 is determined so that the angle θ is an acute angle.

Because of this configuration, a component F1 of the frictional force F acting on the plate edge in the plane γ direction acts in a direction away from the photoreceptor, as is clear from the figure.

Therefore, on both sides of the rotating shaft 4 of the cleaning blade 1, if the frictional force on one side is stronger than that on the other side, a torque is applied that causes the blade edge on that side to separate from the photoreceptor, causing friction. The blade edge on the side where the force is smaller tends to come into stronger pressure contact with the photoreceptor. Following this process, the torque disappears when the frictional forces on both sides of the rotating shaft become equal, so that a uniform frictional force is always obtained on both sides of the rotating shaft.

The above description has been made regarding the counter type blade shown in FIG. 3, but the same is true for the forward type shown in FIG. 2. In this figure, parts corresponding to those in Figure 3 are given the same reference numerals, so a detailed explanation of their configuration and operation will be omitted, but their functions are similar to those shown in Figure 1. This is something that can be understood immediately.

Regarding the magnitude of the angle θ, if θ is less than 0, the component force F, which is not shown, will be in the direction of the plane α or again on the photoreceptor.
Since it acts in the direction of contact, it does not have the effect of equalizing the frictional force.

When testing was carried out with a plate pressure of 3 mm, it was found that the known plate in which the angle θ was an obtuse angle had a cleaning defect after 100 sheets were passed continuously, but when θ = 50. 10 for those who did
It was confirmed that no cleaning defects occurred even after passing 00 sheets.

Although the present invention has been described above in the case where it is applied to a copying machine, it goes without saying that the present invention can also be applied to other image forming apparatuses that utilize an electrostatic transfer process.

In addition, as a cleaning link means, there is a function that reciprocates the cleaning link plate in its longitudinal direction with a moderate stroke, and a function that turns the blade on and off using rotation around the rotary shaft for pressurizing the blade. It is easy to understand that it can also be applied to things that have been prepared.

(3) Effects of the Invention The present invention is based on a cleaning blade arranged on the surface of the image carrier so as to have an equalizing function, so that the frictional effect of the plate always tends to be balanced on both sides of the equalizing rotation axis. With this structure, uniform blade pressure can be applied at all times in the width direction of the image carrier, so that a good leaning function can be obtained over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a side view of essential parts of a counter type cleaning mechanism when the present invention is applied to a copying machine, FIG. 2 is a side view of a forward type cleaning mechanism same as above, FIGS. 3 and 4 1 is a side view of main parts of a known cleaning mechanism. 1.Cleaning blade, 2..Photoconductor, 3..
・Support member, 4...Equalize rotation axis.

Claims (1)

[Claims] In a cleaning device in which a cleaning blade equipped with an equalize function is brought into contact with the surface of an image carrier, an equalize rotating surface on the cleaning blade side;
A cleaning device in which the angle formed between the cleaning blade and the plane tangential to the image carrier at the position of contact with the image carrier is an acute angle.