JPS5850567A - Cleaning device - Google Patents

Abstract

PURPOSE:To prevent a sludge-like toner from raid into a developing electrode, and to improve a quality of an image, by providing a delay time for interposing a suitable time until a pressurizing means is released after an electric power supply has been turned off. CONSTITUTION:An arm 32 supported by a supporting shaft 24, and a cleaning blade 21 are usually detached from a photosensitive drum 1 by a spring 26. In case of cleaning, when the electric power supply is turned on, a solenoid 27 is electrically conducted, an end part 21a of the blade is pressed against the circumferential surface of the photosensitive drum 1, simultaneously, a liquid flows into a cylinder 41 of a delay means 40, and a piston 42 is made to press-contact with the arm 32. When a descending speed of the piston 42 is adjusted by changing a sectional area of a liquid discharge port 45 of the cylinder 41, it is possible to select a delay time required for detaching the blade 21 from the drum 1 when the electric power supply has been turned off. During that time, a liquid developer which has collected between the blade and the cleaning roller is removed, a sludge-like toner does not raid into the developing electrode, and a quality of an image is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a cleaning method in which toner, developer, etc. adhering to the flannel cleaning surface is removed using a blade in an electrophotographic copying machine, an electrostatic recording device, etc. having a wet developing device. It is related to the device.

An example of a copying process of an electrophotographic copying machine having a conventional wet developing device will be described. In FIG. 1, reference numeral 1 indicates a photoreceptor drum, and around the photoreceptor drum 1, which is rotated counterclockwise in the figure, a charger 2, a charger 2,
An exposure device 3, a developing device 4, a paper feed device 5, a transfer device 6, a separation device 7, and a cleaning device 8 are provided.

The circumferential surface of the photosensitive drum 1 is uniformly charged by corona discharge from the charger 2. An optical image of the document is projected onto the peripheral surface of the drum by the exposure device 3, and only that portion loses potential, forming a so-called electrostatic latent image. It consists of four developing devices, a developer container 9, a developer electrode 10, a squeeze roller 11, a developer pump 12, and the like. The developer 13 is stored in the developer container 9 and supplied to the gap between the developing electrode 10 and the photosensitive drum 1 by the image forming barrel 12 . The electrostatic latent image is made visible by toner transfer at a position opposite the image electrode 10. When the squeeze roller 11 disposed on the side of the developing electrode 10 facing the drum rotational force comes into contact with the photosensitive drum 1, excess developer is removed. code 14
indicates an erase lamp.

The paper feeding device 5 includes sheet trays 15A and 15B: paper feeding rollers 16, 16: a pair of registration rollers 17, and the like. For example, for A size sheets, sheet tray 15A
The sheet is placed on the sheet, and is sent to the pair of registration rollers 17 by the frictional feeding of the sheet feed roller 16, where it is temporarily put on standby.

In synchronization with the movement of the visible image without removing all the excess developer and negative solution by the squeeze roller 11,
The visible image is fed to the photosensitive drum 1 through the operation of the o-ra pair 17, and the visible image is transferred onto the sheet via the transfer device 6.

The transferred / - side end is held by the separating device 7 and separated from the photosensitive drum 1 to the fixing device 18 .
and is discharged to the paper discharge tray 19.

Now, on the peripheral surface of the photosensitive drum 1 from which the notes have been separated, the toner T that was transferred and adhered during storage remains. Therefore, a cleaning device 8 is provided to remove this residual toner. The cleaning device 8 includes a cleaning/growler 20, a cleaning blade 21, and the like. The multi-leaning roller 20 has a surface made of a liquid-absorbing elastic material such as sponge rubber, for example, and is pressed against the photosensitive drum 1 while rotating in the same direction. The function of the cleaning roller 20 is to absorb liquid from the circumferential surface of the photoreceptor drum 1, and to move the absorbed liquid (part of the developer) to both sides of the photoreceptor drum 1 and collect it. The toner on the circumferential surface of the photoreceptor drum 1 from which liquid has been removed by the cleaning roller 20 is removed by a cleaning blade (
It is scraped off and removed by a blade 21 (hereinafter simply referred to as a blade).

The blade 21 is made of an elastic material such as urethane rubber, and has a rectangular shape with approximately the same length as the photoconductor tram 1. Half of the blade 21 is fixed to one side of the support plate 22. The support plate 22 is fixed to the holding member 23 via screws. The support shaft 24 is horizontally suspended and swingably supported by an immovable base plate, and fixes the holding member 23 and one end of the arm 25. A sprung ring 26 is interposed between the approximate center of the arm 25 and the immovable base plate, and the blade 21
is given the habit of keeping its free end spaced apart from the photosensitive drum 1 at all times. A lunoid 27 is arranged on the opposite side of the spring 26 in the vertical direction, and the arm 2
5 at the free end. During cleaning, the blade 27 is energized, and the arm 25 and the holding member 23 swing clockwise around the support shaft 24 against the action of the spring 26, allowing the blade 21 to move freely. The end of the blade 21 is pressed against the circumferential surface of the photoreceptor drum 1, and when not cleaning, the free end of the blade 21 is pressed against the spring 26.
Due to this action, it is immediately detached from the photoreceptor drum 1.

However, since the cleaning roller 20 is in pressure contact with the photoreceptor drum 1, when the developing solution is squeezed out on the delayed side in the direction of one rotation of the contact area between the two, it is squeezed out on the opposite side, that is, on the plate 2.
The peripheral surface of the photoreceptor drum 1 past the contact area becomes dry due to the liquid absorption ability exerted on the side of the photosensitive drum 1. However, in the case of long copying work, the contact area inevitably becomes dry. The photoreceptor drum 1 of the blade 21 may get wet even if you plow it.
Sludge-like toner containing liquid collects on the free end that is in contact with the toner.

Therefore, when the blade 21 immediately separates from the photoreceptor drum 1 during non-cleaning, the toner-like toner flows down the circumferential surface of the photoreceptor drum 1, and the developing cathode 1
When the toner enters into the 1IIi image and is copied next time, the toner transfers to the 1IIi image and appears as a black streak.

Further, there are drawbacks such as a decrease in image quality due to the flow down to the eraser/glue 14 and staining of the lamp case, and troublesome maintenance.

The purpose of the present invention is to solve the conventional drawbacks, and to prevent the liquid accumulated between the blade and the cleaning roller from forming on both sides of the reeling surface (
An object of the present invention is to provide a cleaning device in which a plate separates from a cleaning surface after flowing down from a till end.

Such a purpose is to
When the power is turned on, the blade is urged to come into pressure contact with the surface to be cleaned; The cleaning device has a pressure means for releasing the pressure so as to separate it from the surface to be cleaned, and the cleaning device is provided with a delay means for intervening an appropriate time after the power is turned off and the pressure means is released. This is achieved by a cleaning device characterized by:

According to the present invention, the delay means allows an appropriate amount of time between when the power is turned off and when the pressure means is released. The toner can flow down from both sides of the surface, and sludge-like toner does not enter the developing electrode or flow down to the erase lamp, so the quality can be improved without creating black streaks on the image. , and can also be freed from the hassle of maintenance.

The illustrated embodiment will be specifically described below.

FIG. 2 shows a main part of an embodiment of the present invention. In this figure, the free end 21a of the blade 21 is pressed against the circumferential surface of the photosensitive drum 1, which is the surface to be cleaned. The figure shows the state during cleaning. As in the conventional case, half of the blade 21 is fixed to one side of the support plate 22.

The holding member 30 is attached to the supporting member 2 on its upper surface 30a.
2 is fixed via a screw 31, and one end of an arm 32 is fixed via a bolt 33 on its vertical surface 30b. The support shaft 24 is swingably supported on an immovable base plate,
A substantially central portion of the arm 32 is fixed. A spring 26 is interposed between a side plate 32a of the arm 32 opposite to the blade 21 in the longitudinal direction and an immovable base plate.
1 is given the habit of always keeping its free end away from the photoreceptor drum 1. A solenoid 27 serving as a pressure means is disposed on the opposite side of the spring 26 in the vertical direction and is connected to an end (32a) of the arm 32. During cleaning, the solenoid 27 is energized and the arm 32 is rotated clockwise around the support shaft 24 to bring the blade 210's own thread 421a into pressure contact with the circumferential surface of the photoreceptor drum 1. During non-cleaning, the solenoid 27
is demagnetized and the free end 21a of the blade 21 is connected to the spring 2.
6, the photoreceptor drum 1 is moved away from the photoreceptor drum 1 as before.

A feature of the present invention is that the delay means 40 is disposed at a position facing the solenoid 27, that is, along the direction of expansion and contraction of the spring 26.

The delay means 40 includes a cylinder 41. It consists of a piston 42, a hydraulic pump (not shown), etc.

The cylinder 41 has a suction port 43 that sucks liquid discharged from a hydraulic pump, and a suction valve 4 that automatically opens and closes the suction valve 43.
4. It has a discharge port 45 for discharging the liquid that has entered the cylinder 41 into a container (not shown). The cross-sectional area of the discharge port 45 may be configured such that the hydraulic pump is the developer pump 12 (see FIG. 1, the following is omitted), the liquid is the developer 13, and the container is the developer container 9. is easy and cost-effective,
It also has the advantage of being cheaper. The piston 42 is connected to the cylinder 4
1, and a seal ring 4 is fitted on the lower peripheral surface.
6 is fitted to maintain hydraulic pressure. The head of the screw 17420 has a spherical shape so that it can come into smooth contact with the arm 32.

The operation 111 and effects of the heathering device will be explained.

When the switch is turned on, solenoid 27 as before: +fI
? t1. Either the bushing MUM 21a is applied to the circumferential surface of the photoreceptor tram 1 against the action of the spring 26, or at the same time, liquid is sucked in from a hydraulic pump (not shown) through IT143%. The valve 44 is pushed down/entered into the cylinder 41 and the piston 42 is raised.

The screw 1 pin 42 is attached to the arm 3 shown in the position shown in [,;41].
2 (1't rises even more heavily and is stopped by a stopper i=g (not shown) C7. Hydraulic pump, fJ
In the image liquid bottle/Buyoshikane II+, the force/rabbit that is always driven when the power is turned on is 42.
).

Next, when the power goes to 0FFK, solenoid 27 ij
:Although it is immediately demagnetized, since the end 32a of the arm 32 is pressed by the biston 42, the plate 21 is not immediately separated from the photosensitive tram 1.

When the power is turned OFF, the hydraulic pump is stopped and the suction valve 44 closes the suction port 43. Since the liquid in the cylinder 41 is discharged through the discharge port 45, it gradually decreases, and therefore the piston 42 gradually descends. The descending speed of the biston 42 can be adjusted by changing the cross-sectional area of the discharge port 45, and the time required for the plate 21 to separate from the photosensitive drum 1 after the power is turned off can be selected.

In this embodiment, the delay means is a hydraulic pump, a cylinder,
Although a combination of pistons and the like is used, the present invention is of course limited to this.Even if the OFF button is pressed, only the solenoid is energized for a few seconds by a known delay means such as a time relay. Even if you do this, you can achieve one goal.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional cleaning device for extracting an 'if photograph, and FIG. 2 is a block diagram showing the essential parts of an embodiment of the present invention. 1... Photosensitive drum, 21... Blade, 22...
Support plate, 26... Spring, 27... Solenoid,
32...Arm, 40...Delay means.

Claims (1)

[Claims] A blade is positioned either in pressure contact with or apart from the surface to be cleaned that moves in one direction. and the power is OFF'F.
In a cleaning device having a pressurizing means that releases the blade in order to separate the blade from the cleaning surface when the blade is in the L position, an appropriate time is provided between when the power is turned off and when the pressurizing means is released. A cleaning device patented as having a delaying means.