JPS61240271A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent blade rolling-up, cleaning failures, filming, etc., and to form an image of good quality by providing a part which has been made longer than the length of an opposed side, on a part of a carrier side, in a holding means for holding the end part of a cleaning member by the carrier side and its opposed side. CONSTITUTION:The upper part of a cleaning blade 66 consisting of a plate-shaped body is held by an inserting and holding part of the end part of a bent suspending part of two pieces of plate-shaped blade holders 67. As for the blade holder 67, projecting parts 67A1, 67A1 are provided on the part corresponding to non-developed image corresponding areas (a), (a) of both ends in the front suspending part of a member 67A of the side facing a photosensitive drum 20, and made longer than other suspending part 67A2. A rear suspending part 67B1 is set to the length which is equal to that of a shorter suspending part 67A2. In a developed image area (x) in the photosensitive drum 20, a toner is formed by a copy cycle until the previous time, it serves as a lubricant, and the frictional resistance on the abutting surface of the cleaning blade 66 is low. Also, as for the non-developed image corresponding areas (a), (a) of the cleaning blade, its front length and rear length are different from each other, therefore, it can be prevented that the blade 66 is rolled up to the photosensitive drum 20 side.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image forming apparatus equipped with a cleaning device.

[Technical background of the invention and its problems] Generally, in an image forming apparatus such as an electronic copying machine, a cleaning blade (cleaning member) is used to remove untransferred toner (developer) remaining on a photoreceptor drum serving as an image bearing member. It is designed to be scraped off.

By the way, if a large frictional force exists between the photoreceptor drum and the cleaning blade, the photoreceptor drum surface may be damaged, toner may be filmed on the drum, and the blade may not be able to maintain its original contact form due to stress. As a result of investigation, it has been found that due to curling and the electrostatic influence caused by friction, for example, a uniform surface potential cannot be obtained during the charging process, resulting in image unevenness and fogging. Further, in order to reduce the frictional force, the pressure of the cleaning blade may be reduced, but in this case, the original function of cleaning cannot be achieved, resulting in poor cleaning and filming.

Therefore, in the past, attempts have been made to add a lubricant such as wax to the developer as a measure to reduce the frictional force between the blade and the photoreceptor. However, in this case, there are disadvantages in that the lubricant such as wax in the toner deteriorates the toner's fixing properties and causes so-called filming, which is the formation of a thin toner film on the photoreceptor. This makes the image quality highly unstable and prevents its practical use.

In addition, it has been known to apply a lubricant such as wax to the surface of the photoreceptor, but the thickness of the lubricant on the photoreceptor must be set to a level that does not impede the electrostatic properties of the photoreceptor. There was no way to maintain the thickness below about 100 angstroms for a long period of time. Attempts have also been made to improve the blades by using materials with a lower coefficient of friction, but the problem still remains that additives reduce other properties, especially mechanical strength. In addition, conventionally, in blade cleaning type copying machines, the hardness of the photoreceptor is much smaller than that of Fe, At, etc.
(around 112), when a blade or the like comes into contact with a stationary drum, a situation often arises in which the photoreceptor is deformed by pressure over time, which significantly deteriorates image quality and reliability.

For this reason, conventional means have been practically used to release the contact between the blade and the drum when the drum is stationary.

However, the method in which the blades are brought into contact and released has a drawback in that the blades themselves become stained with toner, resulting in poor images.

Further, when the cleaning blade is located above the photoreceptor, there is a drawback that when the blade is released, the toner that cannot be cleaned often stains the inside of the machine. Furthermore, as a result of imparting such movement to the blade, there is a problem in that the accuracy of contact with the photoreceptor is likely to be disturbed.

Additionally, during the initial installation of the photoreceptor drum, there are cases in which operators or service personnel generally scatter lubricating powder such as polyvinylidene fluoride with a thickness of about 5 μm on the drum to reduce the friction between the drum and the blade. ,
Because the work is done manually, there is frost and there are problems with reliability as the drums are touched during the work.

Other attempts have been made to form a single layer of toner on the photoreceptor during initial setting. As shown in FIG. 6, first the drum is rotated, and at the same time, the developing bias is reversed to form a single layer of toner on the photoreceptor during AJIII, and then BJIJI during the second rotation of the drum.
By bringing the blade into contact with Ifl, the toner layer is used as a lubricant. However, in the contact area between the photoreceptor and the blade, where a single layer of toner is not formed, the 1II11j resistance is still large, and there is a problem that the blade turns over and damages the photoreceptor.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and its object is to provide an image cleaning device that has a relatively simple configuration and is capable of solving the above-mentioned problems. An object of the present invention is to provide a forming device.

[Summary of the Invention] To achieve the above object, the present invention provides an image forming apparatus including a cleaning device that performs cleaning by bringing the tip of a cleaning member held by a holding means into contact with an image carrier.
The holding means holds the end of the cleaning member on the image carrier side and the opposite side thereof, and includes a portion in which at least a portion of the image carrier side is longer than the opposite side. It is characterized by this.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 to 3 show the external appearance of an electronic copying machine to which the image forming apparatus of the present invention is applied. In the figures, 1 is a copying machine body with a built-in copying mechanism, and 2 is attached to the right side of the copying machine body 1. A paper feed cassette 3 is a paper discharge tray mounted on the left side of the main body 1 of the copying machine. Further, on the top surface of the copying machine main body 1, there is provided a document table 4 that can freely reciprocate in the left-right direction (in the direction of arrow a'). ..., exposure setting key 7a,
7b, an operation panel 10 on which input keys including a print key 8 and the like are arranged is provided.

The document table 4 has a structure including an original loading plate (glass plate) 12 on which a document 11 is placed and a document cover 13 covering the upper surface thereof.

Further, the cassette cover 14 of the paper feed cassette 2 has a third
As shown in the figure, there is provided a manual paper feed tray 15 for manually feeding paper P- as appropriate. In addition, 16 shown in Figure 3
is the power switch.

Next, the internal mechanism of the electronic copying machine will be explained with reference to FIG. In the figure, reference numeral 20 denotes a drum-shaped photoreceptor (photoreceptor drum) disposed approximately in the center of the copying machine main body 1. The photoreceptor drum 20 is synchronized with the document table 4 in the direction of arrow b' by a drive mechanism (not shown). It is driven by First, a document image uniformly charged by a charger 21 and uniformly irradiated by an exposure lamp 22 is formed on a photoreceptor drum 20 by a focusing light transmitter (product name: Self-Oak Lens Array) 23. An electrostatic latent image is formed.

The formed electrostatic latent image is converted into toner acid by a developing device 24 including a developing roller 24A and sent to the transfer charger 25 side.

Automatically or manually fed paper P or P' is in the paper feeder! 26, and the toner image previously formed on the photosensitive drum 20 is transferred onto the paper P or P' by the transfer charger 25. Furthermore, the toner image is peeled off from the photoreceptor drum 20 by a peeling charger 27 using AC corona discharge, passes through a conveyance path 28, and is melted and fixed onto a paper P (P'') by a fixing device 29, and is then moved to a tray that can be attached or detached by an ejection roller 30. 3. On the other hand, paper P (
After the toner image is transferred onto the photoreceptor drum 20, the residual toner remaining on the photoreceptor drum 20 is removed by a cleaning device (cleaning device f).
) 31 and the photoreceptor drum 20 is cleaned by the bypass slit light 32 which branches the light from the exposure lamp 22.
The upper potential is lowered to a partial level or lower to make the next copy operation possible.

A fan 33 serves as a cooling device, and exhausts heat generated from the heat-generating exposure lamp 22 and the fixing device 29 inside the machine.

Inside the copying machine main body 1, an upper frame and a lower frame (not shown) are pivotally supported at one end via a support shaft 37, and the other ends of both frames are configured to be opened at a desired angle, for example, 25 degrees. ing. The upper frame is provided with a charger 21, a focusing light transmitter 23, an exposure lamp 22, a developing device 24, etc. around the photoreceptor drum 20. Each device such as a cleaning device 131 and a snow removal lamp 32 is attached by appropriate means, and a fan 33 as a cooling device, a paper feed roller 38 of the paper feed device 26, and a document table 4 are also attached to the frame and the upper unit. It constitutes 1A. Also, paper feed cassette 2, transfer charger 25, peeling charge? 27, a conveying path 28, a forming guide plate 39, a fixing device 29, a pair of discharge rollers 30, a tray 3, and other mechanisms are attached by appropriate means to constitute the lower unit 1B. Then, the front cover 1a of the copying machine main body 1
After rotation and removal, the structure is such that the paper P (P-) can be opened and closed along the transport path 28 of the paper P (Pl) via a housing opening/closing device (not shown). Even if paper gets jammed, it can be easily retrieved.

In addition, 50.50 in FIG. 3 corrects the inclination of the leading edge of automatically fed paper P or manually fed paper P- in the paper feed cassette 2, and forms a toner image on the photoreceptor drum 20. Paper P or P according to the timing of the movement.
' is a pair of registration rollers that supplies the paper to the transfer charger 25, and 51 is a paper detection switch disposed immediately before the pair of registration rollers 50 and 50.

52 is a paper feed switch, 53 is a total counter, 54 is a paper empty switch that detects when the paper P in the paper feed cassette 2 is empty, and 55 is a developing device 24.
56 is a toner cartridge, 58 is a toner concentration detector, and 59 is a developer upper cover, which prevents the document table 4 from moving unless these are closed. Further, through this opening, the toner cartridge 56 can be replaced and the developing device 24 can be replaced 9 and removed.

Further, 60 is a high voltage transformer, and a shield case for the transfer charger 25 and the peeling charger 27 is formed integrally with the casing of the high voltage transformer. Reference numeral 61 designates a static elimination brush 62 as a handle formed for opening and closing the upper unit 1A, 63 a reflector surrounding the back of the exposure lamp 22, and 64 an auxiliary reflector.

Further, 65 is a weight for bringing a cleaning blade 66, which is a cleaning member of the cleaning device, into contact with the photoreceptor drum 20 at a constant pressure, and a solenoid (not shown) causes the blade to move toward and away from the photosensitive drum 20.

Note that 67 is a blade holder (holding means) that holds the cleaning blade.

Note that the reflector 63, the auxiliary reflector 64, and the convergent light transmission body 23 are assembled as one unit.

Next, the relationship between the cleaning device 31, the photosensitive drum 20, the developing roller 24A, and their surroundings will be explained with reference to FIGS. 4 and 5.

In FIG. 4, a cleaning device 31 is arranged on the left side of the photosensitive drum, a developing roller 24A is arranged on the right side of the photosensitive drum, and an exposure lamp 22. An optical system including a convergent light transmission body 23 and the like is arranged. In addition, 21
25 is a transfer charger, and 27 is a peeling charger.

The cleaning device 31 mainly includes a cleaning blade 66 held by a blade holder 67 and a weight 65 attached to one end of the blade holder 67.

The photosensitive drum 20. The relationship between the cleaning blade 66 and the developing roller 24A is as shown in FIG. 5, which is a plan view thereof. This is an area (non-image area) that does not contribute to image formation. The y area of the developing roller 24A is an area where the developer is conveyed, and the length of the cleaning blade 66 is longer than the length of the developing area X! is usually longer than the regions x and y. Here, a portion of the blade holder 67 and the cleaning blade 66 held therein in the longitudinal direction corresponding to the image development region X is defined as a development region, and the remaining both side portions a and a are defined as non-development region. Define.

Next, the configuration of the cleaning device will be explained.

FIGS. 7 and 8 are perspective views of one embodiment showing the relationship between a blade holder 67 as a holding means and a cleaning blade 66 as a cleaning member held therein. It is facing the front.

The one shown in FIG. 7 is a two-plate blade holder 67.
The upper part of the cleaning blade 66 made of a plate is held in the clamping part at the end of the bent hanging part (67A, 67B). Hanging part of member 67A (front hanging part)
Projecting portions 67A1.67At are provided at both ends of the portions corresponding to the non-image corresponding areas a, and the other hanging portions 67A
It is configured to be longer than 2. A hanging portion (rear hanging portion) 67Bl of the holder portion 67B on the rear side has the same length as the shorter hanging portion 67A2.

In the case shown in FIG. 8, the hanging part is the non-image corresponding area a,
It is provided at both ends with a width corresponding to a, and is configured so that the blade is held by the hanging parts at both ends,
The front hanging parts 67Ar and 67A1 are formed to protrude longer than the opposing rear hanging parts 67B1 and 67Bt.

Various other shapes of the holder may be considered, but in short, it is necessary that a portion of the front hanging portion be longer than the rear hanging portion. Moreover, the width to be protruded does not have to be the entire area a, but may be a part of it.

If the holder with the above configuration is used, at least in the area a, since the photosensitive drum side holder part is long, the bending direction is restricted to be in the direction of the short holder, and the blade tip can be turned over to the long holder side. can be prevented.

Next, the operation of the device will be explained.

The photosensitive drum 20 is moved in the direction of arrow b' by a drive mechanism (not shown).
direction in synchronization with the document table 4.

Then, the original image, which is uniformly charged by the charger 21 and uniformly irradiated by the exposure lamp 22, is imaged on the photoreceptor drum 20 by the focusing light transmitter 23 to form an electrostatic latent image. . The formed electrostatic latent image is transferred to the developing roller 24A.
A developing device 24 including a toner image is formed into a toner image and sent to a transfer charger 25 side.

A sheet P or P' that is automatically or manually fed is fed by a sheet feeding device 26, and a toner image previously formed on the photosensitive drum 20 is transferred onto the sheet P or P' by a transfer charger 25. Furthermore, the toner image is peeled off from the photoreceptor drum 20 by the peeling charger 27 using AC corona discharge, passes through the conveyance path 28, is fused and fixed onto the paper P (P'') by the fixing device W129, and is transferred to the paper P (P'') by the discharge roller 30.
I is discharged onto a removable tray 3.

On the other hand, after the toner image is transferred onto the paper P (Pl), the photoreceptor 2
The residual toner remaining on the photoreceptor drum 20 is cleaned by a cleaning device (cleaning device) 31, and the bypass slit light 32, which is obtained by branching the light from the exposure lamp 22, is used to clean the residual toner on the photoreceptor drum 20.
The upper potential is lowered to a partial level or lower to make the next copy operation possible.

Here, the operation of the cleaning device will be described.

As mentioned above, this cleaning device
(P') is for cleaning untransferred toner remaining on the photoreceptor drum 20 without being transferred, and the tip of the cleaning blade 66 held in the blade holder 67 rotates the photoreceptor drum 20. The above function is achieved by protruding in the direction opposite to direction b' and making contact.

Based on the above, the operation of the cleaning device will be explained. Since toner has been formed in the developing area X of the photosensitive drum 20 by the previous copy cycle, this acts as a lubricant, and the frictional resistance between this area and the contact surface of the cleaning blade 66 is low. and the non-image corresponding area a of the cleaning blade 66;
Part a is a holder with different lengths at the front and back, and the drum 20 side is held by a particularly long holder, so the blade 66 can be prevented from being rolled over toward the photoreceptor drum 20 side, and the blade and photoreceptor drum can be separated. The contact between the two can be made uniform. As a result, damage to the surface of the photoreceptor drum 20, drum filming, and damage to the surface of the photoreceptor drum 20 due to the curling of the blade 66 caused by the large frictional stress between the blade 66 and the photoreceptor drum 2o as in the conventional case. image defects caused by frictional electrification that exists between the blade and the drum, as well as poor cleaning and drum filming caused by reducing the blade pressure as much as possible in order to reduce the frictional stress between the blade and the drum. All the drawbacks can be solved and the original functions of the cleaning device can be fully enhanced.

Next, a case will be described in which the above-mentioned initial setting method is used.

For example, when using the photoreceptor drum for the first time or replacing the photoreceptor drum, 1 liter is also required for the developing area.
Since no lubricant is formed, there is a problem of large frictional resistance, so as mentioned above, toner is formed in the developing area during the first rotation, but no toner is formed in the non-developing area fA. .

Therefore, the blade is mounted toward the drum. However, according to the present invention, the bending direction of the blade in the non-image corresponding area a is set to one direction to prevent the above-mentioned curling, so that the above-mentioned problem can be solved.

[Effects of the Invention] According to the present invention described in detail above, it is possible to provide an apparatus that has a simple configuration, can solve problems such as blade curling, poor cleaning, and filming, and can form high-quality images. .

[Brief explanation of drawings]

Fig. 1 is an external view of an apparatus according to an embodiment of the present invention, and Fig. 2 (a
) is a diagram of one mode of the operation part, and the same figure (b) is the same figure (a)
FIG. 3 is a schematic sectional view of the device, FIG. 4 is a sectional view of the cleaning device and its surroundings, FIG. 5 is a plan view showing the relationship among the photosensitive drum, cleaning blade, and developing roller, and FIG. The figure is a time chart of the initial setting method, and FIGS. 7 and 8 are schematic enlarged perspective views of one embodiment of the cleaning blade and holder portion. 20... Image carrier, 24A... Developing roller, 31...
...Cleaning device, 66...Cleaning member, 67...
-Cleaning member holding means. Part 1″・
-'1 Agent Patent Attorney Masayoshi Misawa 1. -11 Meals 5 Suki 1S Figure 6

Claims (3)

[Claims] (1) In an image forming apparatus equipped with a cleaning device that performs cleaning by bringing the tip of a cleaning member held by a holding means into contact with an image carrier, the holding means holds an end of the cleaning member between the image carrier and the image carrier. What is claimed is: 1. An image forming apparatus that is held on opposing sides, and includes a portion in which at least a portion of the image carrier side is longer than the opposing side. (2) The image forming apparatus according to claim 1, wherein the holding means on the image carrier side has a longer range corresponding to an area other than the visible image area on the image carrier. (3) The image forming apparatus according to claim 1 or 2, wherein the holding means holds a portion of the cleaning member in the longitudinal direction.