JPH02267580A - Image forming device - Google Patents

Abstract

PURPOSE:To effectively eliminate residual toner, to be heighten image quality and to facilitate an operation and a maintenance work by mounting an elastic thin plate which is press-contacted and released with respect to an image forming body on the down stream side of a cleaning member. CONSTITUTION:The press-fixing and releasing operations of a cleaning blade 41 and a shielding plate 42 and the identical operations of the elastic thin plate 43 with respect to the periphery of the image forming body 30 are performed according to the on-off condition of a solenoid S1 and to the on-off condition of a solenoid S2 respectively. Then, the lump of the residual toner generated when the blade 41 is retreated from the periphery of the image forming body 30 is dragged up by the leading part of the thin plate 43 in the press-contact condition and removed. Besides, the periphery of the image forming body 30 is released from cleaning action by each retreating and separating action of the blade 41 and the plates 42 and 43. Thus toner image formation is newly attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus in which an image transfer section is arranged horizontally above an image forming member.

[Background of the invention]

An electrophotographic image forming apparatus that forms a color image such as a full color image or a funky color image includes a charger that charges a photoreceptor drum that is an image forming member, an image exposure unit that exposes an image to the photoreceptor drum, and a photoreceptor. A developing device that develops the electrostatic image on the photosensitive drum with toner, a transfer device that transfers the toner image on the photosensitive drum onto recording paper, and the like are arranged around the photosensitive drum.

Among these, the developing units in full-color electrophotographic image forming apparatuses are comprised of three or four developing units each containing yellow (Y), magenta (M), cyan (C) toner, and sometimes black (BK) toner. It consists of a developing device, and while the photosensitive drum rotates three or four times,
Yellow (Y), magenta (M), cyan (C), and black (BK) toner images are formed on the photosensitive drum, and these toner images are transferred to recording paper to obtain a full-color image. There is. When using such an image forming method, the color image forming apparatus can be made compact by making three or four developing units thin and arranging them close to each other.

Japanese Unexamined Patent Publication No. 61-55661 proposes a color image forming apparatus using such an image forming method, in which latent images are formed by three lasers corresponding to three developing devices, and the photosensitive drum and developing device are connected to each other. The container and the cleaning means are integrated into a unit and can be taken out from the main body of the device.

Japanese Patent Application No. 62-320596 discloses one exposure device in which developing devices are placed one on top of the other, and the unit is made into a unit in the same manner and can be taken out from the main body of the device.

The above-mentioned Japanese Patent Application Laid-Open No. 61-55661 and Patent Application No. 62-32
Although the color image forming apparatus described in Japanese Patent No. 0596 contributes to improved maintainability, the developer is likely to spill or get mixed in when the unit is inserted or removed.

Furthermore, Japanese Patent Application Laid-Open No. 72159/1983 describes an example in which the area around the photosensitive drum is formed into a unit in a color image forming apparatus that uses a transfer drum to transfer each color toner image to a recording paper.

In this way, various color image forming methods have been developed for copying color images, each with its own special color, but each method requires an image forming body, a developing device, a cleaning device, etc., as described above. By storing the paper in one cartridge and making it into a unit, it is possible to simplify its handling and maintenance work such as jam removal.

On the other hand, looking at the layout of each of the above-mentioned equipment in a unitized cartridge, the developing unit group is arranged at the bottom of the drum-shaped image forming body, and therefore the image transfer section is configured at the top of the image forming body. An image forming apparatus that has the following configuration can be considered.

With this type of device, the image is transferred to the lower surface of the transfer material, so there is less risk of it being smudged by falling toner, and a high-quality image can be provided. It is also possible to open the door, which has the advantage of further improving the workability of jam removal and maintenance.

[Problem that the invention seeks to solve]

However, when looking at the function of a cleaning device that cleans the residual toner on the image forming body after image transfer, conventional cleaning devices usually perform the cleaning function on the aspect of the image forming body that rotates from the bottom to the top. In contrast, in the image forming apparatus described above, the cleaning device is installed facing the circumferential surface of the image forming body that rotates from above to below. The problem remains that it is not possible to obtain a sufficient leaning effect with this function.

Particularly when the cleaning device is installed at a position above the rotation axis of the image forming body, the cleaning efficiency is significantly reduced in many cases when the image forming body is transported in a state in which it remains after being removed.

As a result of solving this problem and improving the present invention, the present invention provides an image forming apparatus having a cleaning device that can efficiently remove and clean residual toner even when the image forming body rotates in the opposite direction to the normal case. It is intended for the purpose of providing.

[Means for solving problems]

The above object is to form an image characterized by having an image forming body, a cleaning member having a function of releasing pressure on the image forming body, and an elastic thin plate located downstream of the cleaning member that also performs pressure bonding and release. achieved by the device.

〔Example〕

An embodiment of the present invention is shown in FIGS. 1 to 5.

FIG. 1 shows a printer to which the present invention is applied.

The printer has a clamshell structure divided into an upper casing 1 and an apparatus main body 2, and the upper casing 1 can be held at a predetermined open angle using a hinge IA connected to the apparatus main body 2 as a fulcrum. In the closed state, it is integrated with the main body 2 of the device by means of a stopper (not shown).

An image forming body 30 constituting an image forming section of the printer, developing devices 36, 37, 38, and 39 containing yellow, magenta, cyan, and black developers, and a cleaning device 40.
In addition, the charger 35, pre-transfer charger 9, and toner collection box 47 are housed in the integrated process cartridge 3 to form a unit, and a guide member 4 provided on the bottom
Particularly in this embodiment, each of the above-mentioned developing units 36.
The housings 37, 38, and 39 are integrally constructed and are arranged in order downward from the image forming body 30 and facing upward from the rotational upstream direction.

That is, the process cartridge 3 is inserted and mounted in the depth direction of the apparatus main body 2 by engaging the guide member 4 with the handle provided on the front surface, and when pulled out toward the front, the guide member 4 is released and the process cartridge 3 is inserted into the apparatus main body 2. However, since each developing unit is kept with its opening facing upward, there is no possibility of the developer leaking out and falling or getting mixed into other developing units. nothing happens.

The printer has a laser writing system unit B in a space on the side of the process cartridge 3, and a transfer material conveying surface in a part above the process cartridge 3 that spans both the upper housing 1 and the main body 2. We have set up
The image forming body 30 is subjected to laser scanning by the laser writing system unit B from diagonally downward, and is formed by overlapping the circumferential surface of the image forming body 30. A color toner image is transferred to the lower surface of the recording paper.

In this way, the transfer material is transferred to the process cartridge 3.
Since the toner is conveyed horizontally on the upper part of the toner and the transfer surface faces downward, even if the toner spills or scatters from the cleaning device 40 or the like, it will not stain the image surface.

In addition, this device has the following advantages: (1) The paper feeding system is located below, and the center of gravity is set further below, which has great advantages in terms of the structure of the machine.

(2) The transport system can be easily opened in the event of a jam.

Benefits include:

The process of color image copying by the printer is performed as follows.

First, the formation of a multicolor image according to this embodiment is performed according to the image forming system shown in FIG. That is, the color image data input section (Fig. 3 (a)) where the image sensor scans the original image.
) is processed in an image data processing unit equipped with a computer (Figure 3 (b)) to create image data, which is then stored in the image memory (Figure 3 (c)). Stored. Then, the image memory is taken out during recording and stored in the recording section (
For example, the color image forming apparatus shown in FIG. 1 is inputted as shown in FIG. 3(d)).

That is, when a color signal output from an image reading device separate from the printer is input to the laser writing system unit B, the laser writing system unit B outputs a laser beam generated by a semiconductor laser (not shown). is rotated and scanned by a polygon mirror 32 rotated by a drive motor 31, and passes through an fθ lens 33 to three mirrors 34A,
An image forming body 30 whose optical path is bent by 34B and 34G and to which a charge is applied in advance by a charger 35 serving as a charging means.
is projected onto the circumferential surface to form a bright line.

On the other hand, when scanning is started, the beam is detected by the index sensor, modulation of the beam by the first color signal is started, and the modulated beam scans the circumferential surface of the image forming body 30. Therefore, a latent image corresponding to the first color is formed on the circumferential surface of the image forming body 30 by the main scanning by the laser beam and the sub scanning by the rotation of the image forming body 30. This latent image is developed by a developing device 36 loaded with yellow (Y) toner (developing medium) of the developing means, and a toner image is formed on the drum surface. The obtained toner image, while being held on the drum surface, passes under a cleaning device 40, which is a cleaning means, which is separated from the surface of the image forming body 30, and enters the next copy cycle.

That is, the image forming body 30 is charged again by the charger 35, and then the second color signal output from the signal processing section is input to the writing system unit B, and the second color signal is inputted to the writing system unit B, and the second color signal is inputted to the writing system unit B. In the same manner, writing is performed on the drum surface to form a latent image.

The latent image is developed by a developer 37 loaded with magenta (M) toner as a second color.

This magenta (M) toner image is formed in the presence of the previously formed yellow (Y) toner image.

A developing device 38 has cyan (C) toner, and forms a cyan (C) toner image on the drum surface based on a control signal generated by a signal processing section.

Furthermore, 39 is a developing device having black toner, and a black toner image is superimposed and formed on the drum surface by the same process. Direct current or even alternating current bias is applied to each sleeve of each of these developing devices 36, 37, 38 and 39, and jumping development is performed using a two-component developer serving as a developing means to form an image with the substrate grounded. body 30
Development is now possible without contact.

The color image thus formed on the circumferential surface of the image forming body 30 is transferred to the lower surface of the transfer material fed from the paper feed cassette C via the paper feed roller and the paper feed guide in the transfer section.

That is, after this multicolor toner image is charged by the pre-transfer charger 9 to be easily transferred, the transfer belt 50 used as a transfer means, which has been rotated since the start of transfer, is brought into contact with the image forming body 30 and fed. Paper feed roller 1 from paper cassette C
2 and the timing roller 13, the image is transferred onto the supplied recording paper in synchronization with the image formation.

The transfer belt 50 is stretched between rollers 59 and 60,
The roller 60 is rotated in synchronization with the circumferential speed of the image forming body 30, and as the roller 58 moves up and down, it is moved away from or in contact with the image forming body 30.

The roller 58 is attached to a lever 57 that can swing around the axis of the roller 60 as a fulcrum, and is held in the upper position shown by the solid line by an elastic member that biases the lever 57. The transfer belt 50 is moved downward as indicated by a dashed line by the power of a solenoid or the like which operates at the timing of , that is, to a position where the transfer belt 50 is brought into pressure contact with the surface of the image forming member 30 .

As the transfer belt 50, a rubber belt containing conductive cloth is used as a base, and a high resistance layer or an insulating layer having an elastic body with a thickness of 0.5 m+m is provided on the outer periphery.

The transfer belt 50 is charged by a transfer device 51, and a transfer charge having a polarity opposite to that of the toner is applied to perform the transfer. Note that the toner adhering to the transfer belt 50 is removed and cleaned by a transfer belt cleaning device 50A.

The transfer material to which the multicolor toner image has been transferred in this way is an image forming body 3.
It is separated from the circumferential surface of the fixing roller 8 and transported to the fixing device.
After the toner is melted and fixed by 0, the toner is discharged to the outside of the machine via the paper discharge roller 90.

On the other hand, the image forming body 30 from which the transfer material has been separated is cleaned by removing residual toner by the cleaning device 40 according to the present invention.

21st! 1 shows the details of each member constituting the cleaning device 40, and each member described below is housed in a housing 40A and is rotated in a clockwise direction relative to the circumferential surface of the image forming body 30. As shown, it is installed diagonally in the upper right position.

Reference numeral 41 denotes a blade which is a cleaning member that presses against the surface of the image forming body 30 to peel off the residual toner, and 42 denotes a shielding plate located above the blade 41 to prevent the residual toner from scattering to the outside of the housing 40A. , 43 are elastic thin plates located on the downstream side of the blade 41 with respect to the rotational direction of the image forming body 30.
This is for removing toner lumps on the circumferential surface that are generated when moving toward and away from zero.

As is well known, the blade 41 is a plate-shaped member made of hard urethane rubber or the like, and is connected to a blade holder 41a.
An arm 4 held by the blade holder 41a and protruding from the blade holder 41a.
The torsion spring 44 that biases the torsion spring 1b always biases the support shaft 41c in a counterclockwise direction using the support shaft 41c as a fulcrum, that is, it has the habit of pressing the peripheral surface of the image forming body 30 with its tip.

The shielding plate 42 is made of a very thin plate material such as a microphone or a brush, and like the blade 41, the arm 42
It is held by a holder 42a that protrudes from b and is attached so that it can freely rotate around a support shaft 42C.

The arms 41b and 42b of the holders 41a and 42a are both protruded close to the inner wall surface in the rear direction of the housing 40A, and each elongated end thereof is engaged with a pin on the plunger of the solenoid SL.

On the other hand, the thin elastic plate 43 is made of an elastic material such as Mylar, which has low hardness and some rigidity.
A torsion spring 45 biases the arm 43b held by the holder 43a and protrudes from the holder 43a, and the arm 43b is always biased counterclockwise around the support shaft 43c, i.e., like the blade 41, the tip of the arm 43b biases the image forming body 30. It has been given the habit of pressing the situation.

Arm 43b of holder 43a in elastic thin plate 43
Similarly to the arms 41b and 42b of the blade 41 and the shielding plate 42, the arms protrude close to the inner wall surface in the rear direction of the housing 40A, and a part thereof protrudes outside the housing 40A, and the long tip is connected to the solenoid S2.
is engaged with a pin on the plunger.

When cleaning the surface of the image forming body 30, the image forming body is de-charged in advance by a device comprising a lamp 46 and a light guide section 47 installed at the upper part of the housing 40A, so that residual toner is easily removed. Ru.

The operation of pressing and releasing the pressing of the blade 4l and the shielding plate 42 against the surface of the image forming body 30 is performed by turning the solenoid SL OFF and ON, while the elastic thin plate 4
The crimping and crimping release operations in step 3 are performed by the solenoid S2.
This is done by turning OFF and ON, respectively.

That is, in FIG. 2(a), the solenoid S1 is turned off at the start of cleaning and the plunger is in a free state, and the blade 4l is in a free state due to the action of the torsion spring 44.
This shows a state in which both the shielding plate 42 and the shielding plate 42 are in pressure contact with the surface of the image forming body 30, and the residual toner is peeled off and the scattering of the residual toner is prevented. In this state, solenoid S
2 is in the ON state, the plunger is attracted, and the elastic thin plate 43 is placed in a position retracted from the surface of the image forming body 30.

When the residual toner in the image area is completely removed by rotating the image forming body 30 in the state shown in FIG. The plate 42 is rotated counterclockwise to move it away from each tip and the surface of the image forming body 30, as shown in FIG. 2(b). On the other hand, at the same time, the solenoid S2 is turned off, the plunger becomes free, and the elastic thin plate 43 is rotated counterclockwise by the action of the torsion spring 45, so that its tip is brought into pressure contact with the circumferential surface of the image forming body 30.

The elastic thin plate 43 is in pressure contact with at least the image forming member 30.
After this phase continues for the time it takes for the blade 4l to pass between each pressure contact point of the elastic thin plate 43, it returns to the retracted position again by turning on the solenoid S2.

Therefore, the lump of residual toner generated when the blade 4l retreats from the surface of the image forming member 30 is scooped up and removed by the tip of the elastic thin plate 43 that is in pressure contact. If the cleaning is not complete at a position on the image forming body where there is a lump of residual toner, it is preferable to avoid that position and perform the next toner image formation.

In this manner, the circumferential surface of the image forming member 30 is released from the cleaning action by the retracting and separating actions of the blade 41, the shielding plate 42, and the elastic thin plate 43, and a new toner image can be formed by overlapping.

FIG. 4 shows each developing device, each charging and transfer electrode, and the blade 41 in the cleaning device 40.
, the shielding plate 42, and the elastic thin plate 43 with respect to the image forming body 30. In this example, the image forming process by the printer is performed as shown in the time chart of FIG. VI5. By the end of five rotations, the pressing operation of the elastic thin plate 43 against the image forming body 30 is completed, and one cycle of image copying is completed. Furthermore, in order to avoid the influence on the image when the cleaning member is crushed, 4
It is preferable to start pressing the cleaning member after the second image exposure.

The residual toner removed by the cleaning device 40 is collected into a toner collection box 70 attached to the process cartridge 3 via a toner transport pipe 7l installed on the front surface of the process cartridge 3.

A visible toner conveying screw 72 that is rotated by the power system of the main body 2 of the apparatus is built in the toner conveying pipe 7l, and residual toner is conveyed by the driving force generated by the rotation of the screw.

Note that the toner conveying pipe 7l is a pipe member molded from a synthetic resin material with high lubricity so as not to provide resistance to the operation of each toner conveying screw 72.

〔Effect of the invention〕

The present invention provides a cleaning device that can effectively remove and clean residual toner on an image forming body after image transfer for an image forming apparatus in which an image transfer portion is provided above the image forming body. As a result, an extremely useful image forming apparatus for users, which has good image quality and is easy to handle and maintain, has been realized.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the image forming apparatus of the present invention, FIG. 2 is a sectional view of the cleaning device of the apparatus, FIG. 3 is a block diagram of the image forming system, and FIG. 4 is a diagram of each equipment in the image forming apparatus. An explanatory diagram showing an arrangement example, and FIG. 5 is a time chart of image formation according to the arrangement example. 3... Process cartridge 9... Pre-transfer charger 30... Image forming body 35.
...Charger 36.37.38...Developer 40...Cleaning device 41...Blades 41b, 42b, 43b...Arm 43...Elastic thin plates S l, S 2... Solenoid

Claims (2)

[Claims] (1) An image forming apparatus characterized by having an image forming body, a cleaning member having a function of releasing pressure on the image forming body, and an elastic thin plate located downstream of the cleaning member that also performs pressure bonding and release. . (2) The image forming apparatus according to claim 1, wherein the elastic thin plate is pressed against the image carrier when the cleaning member is released.