JPS58184978A - Cleaning device - Google Patents

Abstract

PURPOSE:To improve the durability of a cleaning blade to increase the number of guaranteed copies, by controlling the pressing force of a cleaning blade to the surface of an electrostatic latent image carrier by a controlling means so that this pressing force is weak in the early stage and is increased in accordance with wear of the cleaning blade thereafter. CONSTITUTION:A blade holder 12 holding a cleaning blade 7 is attached pivotally to one end of a pressure applying lever 20 through a pin 13, and the cleaning blade 7 energizes the blade holder 12 in the direction where the cleaning blade 7 is always pressed to the surface of a photoreceptor 1. A motor 24 is arranged on the upper face of a casing 21, and its output shaft extends upward, and a driving gear 26 is mounted fixedly to the output shaft 25, and the driving gear 26 is engaged with a transmission gear 27, and the transmission gear 27 is moved vertically. The transmission gear 27 is fixed to a screw shaft 28 extending downward, and the tip of the screw shaft 28 presses the other end part of a coil spring 23. Since the tip of the blade is not in the direction of escape but in the direction of biting in spite of the trailing system, a high cleaning capacity is obtained even if the pressing force of the blade is restrained to a low value in the early stage, and a minimum pressing force can be set.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blade-type cleaning device for wiping the surface of an electrostatic m@ carrier incorporated in an electrophotographic copying machine or an electrostatic recording device.

A conventional blade-type cleaning device will be explained using an electrophotographic copying machine as an example. In FIG. 1, reference numeral 1 indicates a photoreceptor which is an electrostatic latent image carrier.

The photoreceptor 1 is formed into a drum shape and rotates in the direction of the arrow force plane. On the outer periphery of the photoreceptor 1, charging parts 2. Dew base 3. Developing section 4. A transfer section 5 and a cleaning device 6 are arranged.

Then, the surface of the photoreceptor 10 is uniformly charged with H by the charging unit 2.
4;: '- After the document image is irradiated with a light image corresponding to the original image through the basket base portion 3, an electrostatic latent image is formed.

The developing section 4 is configured to supply a powder developer called toner to the surface of the photoreceptor l via, for example, a rotating sleeve containing a magnet, so that the electrostatic latent image is developed in the developing section 4. The agent is transferred and b] becomes an image. on the other hand,
A paper feeding means (not shown) feeds the transfer paper S to the photoreceptor l in synchronization with the movement of the visible image. The fed transfer paper S has a visible image transferred to it when passing through m between the photoreceptor 1 and the transfer section 5, and is further discharged through a fixing device (not shown). The developer attached as a visible image on the surface of the photoreceptor 1 is transferred to the transfer paper in the transfer section 5, but normally some amount of the developer remains on the surface of the photoreceptor 1. This residual developer is completely wiped off using cleaning device No. 6)
- removed and the photoreceptor 1 is used again θ for this copying process.

The cleaning device f&6 has a cleaning blade 71
Pressurizing means8. Branrolla9. It consists of a discharge coil IO and a casing 11 containing these. The cleaning blade 7 is made of polyurethane rubber or natural rubber, for example, and is fixed to the blade holder 12 with a double-sided adhesive or the like. Blade holder 1
2 is pivotally attached to one end of the pressure lever 14 via the pin 13. A spring (not shown) winds around the bottle 13', and both ends of the spring are latched to one end of the blade holder 12 and one end of the pressure lever 14, respectively, and are oriented f in a direction that constantly presses the cleaning blade 7 against the surface of the photoreceptor l.・] It is in force. The pressurizing lever 14 has an abbreviated cross section, and the center portion is connected to the casing 11 via the bottle 15.
It is pivotally attached to the lateral roots of. A spring 16 is interposed between the other end 14a of the pressure lever 14 and a protrusion 11a planted on the inner wall of the casing 11, and the pressure lever 14 is rotated counterclockwise in the figure with the pin 15 at the center. It is biased in the direction of rotation. A brush roller 9 is arranged upstream of the cleaning blade 7. The brush roller 9 is a roller whose outer periphery is flocked with soft bristles of animal hair or synthetic fibers, and is rotated in a direction opposite to the direction of the photoreceptor 1 while contacting the surface of the photoreceptor 10 . Then, the residual developer is removed from the surface of the photoreceptor 1 by tapping with the tip of the tip and transported. Further, residual developer that cannot be completely removed is wiped off by the cleaning blade 7 and falls, so this fallen developer is received by the brush roller 9 and conveyed. The discharge coil IO is disposed at the bottom of the casing 11 and collects the developer conveyed by the brush roller 9.
It is designed to be discharged outside the casing 11.

By the way, the photoreceptors 11j-j of the cleaning blade 7
The pressing force applied to II depends on the set strength of the spring 16 and the spring interposed between the pressure lever 14 and the blade holder 12. Moreover, since the portion of the cleaning blade that comes into contact with the surface of the photoreceptor l is always the same and has a small area, wear progresses. Therefore, even if the pressure contact force is set appropriately, the pressure contact force decreases due to the width increase due to the jlJQ defect, resulting in poor cleaning performance. !
j! The relationship between cleaning performance and pressure force is shown. In this figure, the horizontal axis shows the wear width, and the vertical axis shows the wear width.
I shows the pressure contact force, which is expressed as a force per unit length of the cleaning blade in the longitudinal direction.

The shaded area in the figure shows the range that can be cleaned.
It can be seen that a cleaning blade that was damaged by a pressing force of approximately 129/an at the initial stage cannot exhibit good leaning performance unless a pressing force exceeding 20/an is applied when the cleaning blade wear width is 30 μmK. Third
The reason shows the relationship between the number of sheets passed, the pressing force, and the width of wear. In other words, when the contact force is set to 25yΔ, the number of sheets that pass through until the cleaning blade wear width reaches 20μ+nK is approximately 30,000 sheets, but when the contact force is set to 40'/an, the number of sheets that pass through is approximately 20,000 sheets. With a contact force of 50yΔ, it is approximately 15
10,000 sheet AI (number of sheets). If the setting value of the pressure contact force cannot be changed, it is necessary to set a pressure contact force of 100,000 sheets with a margin in consideration of various conditions. In this case, If cleaning is possible until the abrasion width is 40 μm, the number of sheets that can be passed through is approximately 40,000, which indicates the durability of this cleaning blade.
When guaranteeing 100,000 sheets, it is necessary to increase the contact force to the extent that the cleaning blade can be cleaned by the wear width of the cleaning blade, and this has the drawback that unnecessary excessive pressure is applied in the initial stage, accelerating wear.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning device that can overcome the above-described conventional drawbacks, improve the durability of the cleaning blade, and increase the number of guaranteed sheets.

The purpose of this is to provide a cleaning blade that wipes off residual developer by adhering it to the surface of the rotating electrostatic latent image carrier and wiping off the residual developer. A cleaning device comprising a pressure means for bringing the surface of the latent image carrier into pressure contact with the surface of the latent image carrier, further comprising a control means for controlling the pressure exerted by the pressure means on the surface of the electrostatic latent image carrier (7j) of the cleaning blade. This is achieved by a cleaning device specially designed for this purpose.

According to the present invention, the pressure force of the cleaning blade against the surface of the electrostatic latent image carrier is initially small by the control means, and thereafter
Since the cleaning blade can be increased in size as the size increases to 4A, the durability of the cleaning blade is improved and the guaranteed number of cleaning blades can be increased.

Hereinafter, the embodiment will be described in detail with reference to FIG. 4. In this figure, components that are the same or equivalent to those of the prior art are designated by the same reference numerals and their explanations will be omitted.

This embodiment has a link system similar to that of the cleaning device shown in FIG. The lever 20 has an oval-shaped cross section and is pivotally connected to the casing 21 via the pin 15 at its central portion i. Both ends of a torsion spring 22 wound around the outer periphery of the bottle 13 are respectively engaged with the blade holder 12 and the pressure lever 20. is energized. Pressure lever 2
One end of 0 is a vertically long hole 2 bored in the wall of the casing 21.
It penetrates 1a and protrudes outward, and is adapted to lock one end of the coil spring 23.

On the other hand, a motor 24 is disposed on the upper surface of the casing 21, an output shaft 25 of which extends upward, and a drive gear 26 is fixedly attached thereto. The drive gear 26 is engaged with a transmission gear 27, and as will be described later, the transmission gear 27 moves up and down.
The height of the driving gear 26 is set high so that the engagement with the transmission gear 27 does not come off even during vertical movement. The transmission gear 27 is fixed to a screw shaft 28 extending downward.
The tip of the coil spring 23 is adapted to press the other end of the coil spring 23. Reference numeral 29 denotes a support stand, which is fixed to the upper surface of the casing 21 via legs 29a, and has a hole through which the output shaft 25 of the motor 24 faces and a screw hole that engages with the screw of the screw shaft 28. The rotation of the transmission gear 27 allows the screw @28 to move up and down correctly via the screw pair.

Next, although not shown, means for inputting a rotation command to the motor 24 will be explained. First, there is a method in which a rotation command is issued when a predetermined value is reached by multiplying and calculating the copying machine operation time or the number of copy branches. This is a method of turning on the switch manually by looking at the 4 display that has reached the value. There is also a method of optically detecting the degree of contamination on the surface of the photoreceptor after cleaning and automatically rotating the L/L motor, and a method of manually determining the degree of contamination found on the copy. As for the manual method, a method in which the motor is rotated by a service person may also be considered.

With the above-mentioned configuration, this device has the advantage of link-type cleaning, that is, although the tip of the cleaning blade is a trailing type, when it is activated, it is not in the escape direction but in the biting direction. Is the contact force of the cleaning blade 1O~15J? /cyz
Good leaning performance can be obtained even if the value is kept to a low value.
In addition to being able to set the minimum pressure contact force, the motor can be rotated to lower the screw to compress the coil spring in response to variations in the machine, variety in use, and changes in the environment.
, the pressure contact force of the cleaning blade can be increased, and the durability of the cleaning blade can be dramatically improved. This is illustrated in Figure 5. In this figure, the horizontal axis shows the number of sheets passed, and the vertical axis shows the wear width of the cleaning blade. A variable pressure method that can change to force
It is understood that this has the effect of approximately doubling the number of sheets passed. That is, by the time the maximum abrasion width reaches 40 μm, the number of sheets can be increased from approximately 40,000 sheets according to the conventional method to approximately 75,000 sheets using the present horn method.

In the above explanation, a motor was used to control the pressure contact force of the cleaning blade, but the invention is not limited to the motor; for example, a method of using a solenoid to act on a cam to compress a coil spring may be used. It's okay. Alternatively, it is of course possible to use means for manually compressing the coil spring.

In addition, the object to be cleaned may be not only a photoreceptor but also a dielectric of an electrostatic recording device, and it may be an endless belt rather than a drum.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional cleaning device, FIGS. 2 and 3 are diagrams for explaining the performance of the conventional device, FIG. 4 is a block diagram showing the cleaning device of the present invention, and FIG. It is a diagram for explaining the effect of this device. 1... Photoreceptor, 7... Cleaning blade, 12
...Blade holder, 14, 20...Pressure lever, 22...Torsion spring, 23...Coil spring, 24...
...Motor, 26...Drive gear, 27...Transmission gear. 'Ff) σ A sheet to the monthly pass - rf) The number of water that does not go back 10 times in 4 years -

Claims (1)

[Claims] A cleaning blade that wipes off the residual developer by pressing it against the surface of the rotating electrostatic latent image carrier, which is attached to the surface of the electrostatic latent image carrier, and this cleaning blade is attached to the surface of the electrostatic latent image carrier. In the cleaning device, the cleaning blade has a pressurizing means that presses the surface of the cleaning blade by the pressurizing means. A cleaning device characterized by comprising a control means for controlling a pressing force against the surface of a W image carrier.