JPS60169885A - Cleaning device of image forming device - Google Patents

Abstract

PURPOSE:To delay displacement and prevent a cleaning blade from oscillating by providing a member which absorbs the operation energy of the blade when the blade is separated from a photosensitive drum. CONSTITUTION:The blade 1 is pressed against the surface of the photosensitive drum 2 with a weight 34 fitted to a blade holder 33. When a solenoid 5 is turned off, an armature 6 stops pressing an arm 7, so the arm 7 is rotated by being drawn by a spring 9 and the blade 1 leaves the surface of the photosensitive drum 2. The armature 6 is pressed against an oil damper 31, so it is never displaced abruptly, so that the blade 1 does no oscillates during movement.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement of a cleaning device in an image forming apparatus such as an electrophotographic apparatus or an electronic printing apparatus.

[Technical background of the invention and its problems]

In an image forming apparatus, for example, an electrophotographic apparatus, a developer image (toner image) formed on the surface of an image carrier (hereinafter referred to as a photoreceptor) is transferred onto a transfer paper, and then the developer image is fused by a fixing device. It is configured so that it can be placed on the transfer paper.

After the developer image is transferred, a small amount of developer remains on the surface of the photoreceptor without being transferred, and this residual developer is completely removed from the surface of the photoreceptor in order to adversely affect the next copy. It is necessary to do so.

For this reason, this type of image forming apparatus is generally provided with a cleaning device for removing residual developer from the surface of the photoreceptor. As one such device, a cleaning device using a cleaning blade (hereinafter simply referred to as blade) 1 shown in FIG. 1 has been put into practical use. This blade type cleaning device presses the tip of a blade 1 against the surface of a photoreceptor 20 to peel residual developer TfL from the surface, and sends the peeled residual developer T through a collection blade 3 into a spiral for collecting the developer. A shaped O is led to 4, and this O is configured to be conveyed by 4 to an external developer collection box (toner box) not shown.

On the other hand, when the blade 1 is constantly pressed against the photoreceptor 2 in this type of blade-type cleaning device, changes in the environment,
Due to the contact pressure of the blade and the condition of the edge of the blade, the portion of the photoreceptor 2 that contacts the blade 1 may be deformed or damaged, resulting in white or black streaks appearing in the copied image. A method is adopted in which the photoreceptor 2 is pressed into contact with the photoreceptor only at certain times, and separated while the photoreceptor 2 is stopped.

Conventionally, the one shown in FIGS. 2 and 3 is known as an example of this blade contact/separation mechanism.

The solenoid 5 causes the armature 6 to push down the L-shaped arm 7, causing the cam 8 to fall downward, and the blade 1 to be pressed against the photoreceptor 2. Further, when the solenoid 5 is disconnected, the spring 9 causes the L-shaped arm 7 to push the cam 8 upward and separate the blade 1 from the photoreceptor 2. Note that the method of moving the blade 1 toward and away using the solenoid 5 is faster than the method using a motor drive.
This is an excellent method because the blade 1 is always separated even if the power switch is turned off during copying.

It has been confirmed that the conventional method described above has the following drawbacks.

First of all, as the blade 1 is suddenly separated, the blade 1 itself suddenly recovers its elasticity, causing the photoreceptor 2 to move as shown in FIG. 4 (a).
) , (b) I As shown in (c), it can be slightly rotated by four dimensions in the forward direction, so it is shown in Fig. 5 (a).
, As shown in (b), the developer T remaining on the edge 1a of the blade 1 during pressure contact (the state shown in FIG. 5(a)) is removed during separation (
The state shown in Figure 5(b)) is separated into the forward direction -\
If it advances slightly, the next time the blade 1 comes into pressure contact, the developer T will be caught between the edge of the blade 1 and the back surface of the blade 1 and the photoreceptor 2, resulting in the occurrence of black streaks in the image and the development. At the same time as the agent T, scraps of paper or the like may be caught, resulting in poor cleaning or scattering of the developer onto the static eliminator lamp or charger. As a result, the developer T entered the back side of the blade 1, causing the above-mentioned problem.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and its object is to provide a cleaning cloth.

An object of the present invention is to provide a cleaning device for an image forming apparatus, which can prevent developer from going around to the back surface of the radar, thereby preventing black streak images from occurring, and preventing contamination of the periphery H by the developer. be.

[Summary of the invention]

In order to achieve the above-mentioned line of sight, when the blade is separated from the image carrier by a blade contact/separation means for moving the blade toward and away from the image carrier, the present invention does not do it instantaneously, but over a predetermined period of time. This configuration includes a separation time adjusting means separated from the image carrier.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIGS. 6 to 8.

FIG. 6 is a schematic longitudinal sectional front view showing an embodiment of an electrophotographic apparatus using the cleaning device of the present invention. In the figure, reference numeral 10 denotes a document table fixed to the main body 11 of the apparatus, and an exposure device 12 is provided below the document table. In this structure, a lamp 13 and a first mirror 14 move together to sequentially illuminate the surface of the document placed on the document table 10 while optically operating (scanning) it. Furthermore, a second mirror 16 is provided to reflect the reflected light from the first mirror 14 and make it enter a lens 15 provided beyond the first mirror 14. This second mirror 16 can be moved while keeping the optical path length from the first mirror 14 to the lens 15 constant. Further, a fixed mirror 18 is provided to irradiate the light transmitted through the lens 15 onto the surface of a photoreceptor 20 serving as an image carrier provided approximately at the center of the apparatus main body 11, and the light irradiated by the lamp 13 is provided. The image of the original is formed on the surface of the photoreceptor 2 by the exposure device 12 . The charging device 1 is still in the vicinity of the photoreceptor 2.
9 is provided, and an electrostatic latent image is formed on the surface of the photoreceptor 2 charged by this charging device N19 by illumination during the image formation. Then, toner (developer) is attached to this electrostatic latent image by the developing device 20, and the image is visualized. Further, on the side of the apparatus main body 11, a cassette 21 containing paper P and a transport roller 2 are provided.
A paper feed device 23 consisting of a pair of registration rollers 24 is provided, and the paper P sent out by this device passes through a pair of registration rollers 24.
After being brought into contact with and aligned, the developer constituting the developed image is transported to the circumferential side of the developed image formed on the surface of the photoreceptor 2, and then transferred by the transfer device 25. is transferred onto the transported paper P, and then the fixing device 26
The image is fixed thereon and then taken out onto a tray 27.

A cleaning device 28 is provided near the photoreceptor 2, and the photoreceptor 2 of the transfer machine is cleaned by this cleaning device 28. In addition, the 1゛ dot-dashed line in the figure indicates the conveyance path of the paper P.Furthermore, the main body 11 of the apparatus is pivotally supported at one end by the upper frame 11 and the lower frame IIB. The other ends of IIA and IIB are configured so that they can be opened at a desired angle, for example, 25 degrees. A photoreceptor 2, a cleaning device 28, a developing device 20, a document table 10, etc. are attached to the 11 upper frames, respectively, and constitute an upper unit.
Further, a cassette 21, a transfer device 25, a fixing device 26, a tray 27, etc. are respectively attached to the lower frame JIB to constitute a lower unit, and 11 copies of copy paper P are transferred via an opening/closing device (not shown) to the main body of the apparatus. It is configured so that it can be opened and closed in the direction of arrow y (vertical direction in the drawing) with reference to the conveyance path. Therefore, when copy paper P becomes jammed on the conveyance path, it can be easily taken out.

The cleaning device 28 is arranged in a casing 29 so that the cleaning blade 1 comes into contact with the surface of the photoreceptor 2. A spiral-shaped orifice 4, which is a conveying member for conveying the collected developer (toner) to the toner box, is arranged below the blade 1.
A collection blade 3 is arranged between the photoreceptor 2 and the auger 4.

Further, as shown in FIGS. 7 and 8, the blade 1 is brought into contact with and separated from the photoreceptor 2 by a blade contact/separation mechanism 30, and the blade 1 is separated from the photoreceptor 2 by a separation time adjustment means 31. When the two are separated, they are not separated instantaneously but gradually over a predetermined period of time, that is, at least 0.5 seconds.

That is, the blade 1 is held by a swingable blade holder 33 that is integrally attached to a shaft 32 that is horizontally suspended parallel to the axis of the photoreceptor 2 . A weight 34 is attached to the lower play holder 33 and is always biased clockwise in a predetermined direction, that is, in the state shown in FIG. The structure is such that it can be pressed against the surface of the body with appropriate pressure.

Further, a cam 8 is attached to the shaft 32 to which the blade holder 33 is attached, and its free end faces the upper surface of the horizontal piece 7a of the L-shaped arm 7, which is rotatable about the support shaft 35. The situation is as follows.

A coil spring 9 is connected to the lower end of the vertical piece 7b of the above-mentioned arm 7, and urges the L-shaped arm 7 to always rotate in a predetermined direction (counterclockwise in the state shown in FIG. 7). The cam 8 attached to the shaft 32 is pushed up by the horizontal piece 7a.

The blade holder 3 is integrally connected to the cam 8.
3, the blade 1 is held apart from the photoreceptor 2 against the biasing force of the weight 34.

Further, the free end of the armature 6 rests on the upper surface of the free end side of the horizontal piece 7a of the L-shaped arm 7, and as the armature 6 is attracted by the solenoid 5, the above-mentioned armature is 7 is rotated against the biasing force of the coil spring 9, and the L-shaped arm 7 is separated from the cam 8.

However, when the solenoid 5 is in the energized state, the ldL type arm 7 is separated from the cam 8, and the blade 1 is in the weight 34.
When the solenoid 5 is brought into pressure contact with the photoconductor 2 by the biasing force of the coil spring 9, the L-shaped arm 7 is rotated by the biasing force of the coil spring 9, pushes up the cam 8, and pushes the blade 1 against the photoconductor. The operating rod 36a of the oil damper 36 as the separation time adjusting means 31 is in contact with the upper surface of the free end side of the armature 6 of the blade contact/separation means 30 configured in this way. It is in a state of being

However, in the above configuration, after the solenoid 5 is electrically turned off, the coil spring 9 engages the L-shaped arm 7 to prevent the cam 8 from being suddenly raised upwards, thereby preventing the blade 1 from suddenly moving upward. Also, when the solenoid 5 attracts the armature 6, the damper 36 does not hinder the movement of the armature 6 at all, but comes into contact with the upper part of the armature 6 with a slight delay. It has been experimentally found that the damper 36 is most preferably set so that it takes 0.5 seconds or more for the blade 1 to separate from the photoreceptor 2.

That is, the blade 1 is made of rubber, and if the pushed blade 1 is suddenly released, the restoring force of the blade 11 causes the tip 1a of the blade 1 to return too far in the direction of the photoreceptor 2. , at that time, the photoreceptor 2 is pushed too far. To prevent this, it is necessary to gradually return the rear end side of the blade 1, and the time required for this return is 0.5 seconds or more.

The above device eliminates the slight rotation of the photoreceptor 2 in the forward direction and the vibration of the blade 1, preventing black streak images and developer scattering.
It was confirmed that cleaning defects can be prevented.

It should be noted that the above embodiment is merely an example, and it goes without saying that each member can be replaced with another member having the same function. For example, in the above embodiment, the cleaning device is applied to an electrophotographic device in which the optical system moves, but the present invention is not limited to this, and the cleaning device can also be applied to an electrophotographic device in which the document table moves. Needless to say.

In addition to the oil damper, an air damper or another energy absorbing member such as a sponge may be used as the distance adjusting means 31 in the same manner.

In addition, it goes without saying that the present invention can be modified in various ways without departing from the gist of the invention.

〔Effect of the invention〕

Since the present invention is configured as described above, it is possible to prevent a black streak image from occurring due to developer falling from both ends of the cleaning device and developer flowing around or as a result of the developer to the back side of the blade, and to use a static eliminator lamp and a charging device. It is possible to prevent contamination of the surrounding area by the developer, and also to prevent poor cleaning of the photoreceptor caused by paper scraps being caught in the blade. In addition, the structure is extremely simple, inexpensive, and the drive mechanism is simple, which are excellent effects.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram of a cleaning device, Fig. 2 is a longitudinal sectional front view showing a blade pressure contact mechanism in a conventional cleaning device, Fig. 3 is a side view, and Fig. 4 (a)
l (b) and (e) are schematic explanatory diagrams showing how the photoreceptor advances when the blade is separated, and Figures 5 (a) and (b)
6 to 8 show an embodiment of the present invention, and FIG. 6 shows an electronic device to which the cleaning device of the present invention is applied. FIG. 7 is a schematic longitudinal sectional front view showing the photographic apparatus, FIG. 7 is a longitudinal sectional front view showing a blade approaching and separating mechanism, and FIG. 8 is a side view. T...Developer, 1...Blade, 2...Image carrier (photoreceptor), 28...Cleaning device, 30...
Blade contact/separation means, 31... Separation time adjustment means. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (4)

[Claims] (1) A cleaning device for an image forming apparatus that removes residual developer on the image carrier by bringing a blade into contact with the surface of the image carrier, and separates the blade from the image carrier after the cleaning operation is completed. , a blade approaching/separating means for bringing the blade into contact with and separating from the image carrier, and a blade approaching/separating means that separates the blade from the image carrier not instantaneously but over a predetermined period of time. 1. A cleaning device for an image forming apparatus, comprising a separation time adjusting means for separating the cleaning device from the image forming apparatus. (2) A cleaning device for an image forming apparatus according to claim 1, wherein the separation time adjustment means is constituted by an energy absorbing member that absorbs operational energy to an operating body that transmits movement to the blade. (3) In the image forming apparatus according to claim 1, the separation time during which the blade is separated from the image carrier is at least 0.5 seconds or more at which no vibration occurs in the blade. Device. (4) The cleaning device for an image forming apparatus according to claim 3, wherein the energy absorbing portion side is comprised of a toothed damper or an air damper.