JPS6083072A - Image forming device provided with image carrying belt - Google Patents

Abstract

PURPOSE:To enable to maintain the space between an image carrying belt and an image forming device always constant by holding movably the image forming device by a pair of independent holding member and making the image forming device have degree of freedom against a space forming device. CONSTITUTION:A developing device 30 is normally deviated in counterclockwise direction by repulsive force of a spring 45, and a developing roller 31 is kept standstill keeping prescribed small space (d) to a belt 9. An image is formed on the surface of the belt by passing of the belt 9 between the small space (d). A developing roller 31, bottom board 54 etc. provided between side boards of the developing device 30 are loosely fitted or flexibly structured to side boards to allow side boards 39, 40 to rotate to some degree against a fixed axis 44 as the center of rotation of the developing device, and deviated independently by compression springs 45. Accordingly, the space (d) between the photosensitive belt 9 and developing roller 31 can be kept constant always even after repeated operation for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an image forming apparatus that supports an image carrying belt, and more specifically, an image forming apparatus which has an image carrying belt, and more specifically, has an image forming apparatus which has an image carrying belt which is made into an endless shape by joining both ends thereof, and where this joining part is larger than the other image holding part. This image forming apparatus is provided with an image carrying belt having a shape similar to that shown in FIG. .

Conventionally, there are two types of endless image bearing belts (hereinafter simply referred to as belts) such as photosensitive belts: those using metal and those using resin film. In the case of metal, Nisokur is generally used.

Metal-based belts have good durability and accuracy, but because they are opaque, they cannot be used in devices that provide image exposure from inside the belt. On the other hand, in the case of a belt using a resin film as a base, a transparent belt can be manufactured, which is convenient for an apparatus that applies image exposure from inside the belt. However, it is difficult to manufacture a completely endless belt having the same thickness and characteristics on all sides from the beginning using this transparent resin film, and even if it were possible, it would be extremely expensive.

On the other hand, when this endless belt is used as a photosensitive belt, it is necessary to provide a transparent conductive layer on the surface of the belt, making it even more difficult to manufacture a completely endless belt. Generally, when manufacturing an endless belt using transparent resin film, a long transparent sheet is made conductive by vapor-depositing a thin metal film on its surface, and then cut to a predetermined length. Endless belts were made by joining the ends together. However, the endless belt produced in this way is thicker at the joint than at other parts. Particularly, in the case of an endless belt formed using an elastic member such as rubber, the joint portion becomes thick.

When a photoreceptor belt with such a thick joint is rotated, developer (hereinafter referred to as toner) is pushed each time the joint passes through the developing section (image forming section). The particles tend to aggregate, and the deterioration of the toner is also accelerated.

If the toner aggregates, there will be insufficient development, resulting in black or white streaks, resulting in a very sharp image.

Further, the toner pressed at the joint portion adheres to this portion and rotates together with the photosensitive belt, causing toner scattering and toner waste. Furthermore, in the case of a developing process in which the gap between the photosensitive belt and the developing roller (the negative component of the image forming means) is very narrow (about 1 mm to 2 mm), the joint portion passes through the developing section. At times, it is unavoidable that the joint portion contacts or collides with the developing roller. If this contact or collision occurs, not only will the rigidity of the joint be significantly impaired, but it will also cause the photoreceptor belt to meander. Furthermore, since the speed of the photosensitive belt momentarily slows down, the image positioning control mechanism becomes complicated.

Furthermore, the impact may cause toner adhering to the image bearing surface of the photoreceptor belt to fall.

Therefore, in order to eliminate this inconvenience, when the joint comes to the image forming section, the image forming means is already retracted to a non-contact position to prevent contact between the joint and the image forming means. I can think of something to do. However, if the image forming means is allowed to operate in this manner, it becomes difficult to maintain a constant gap between the photosensitive belt and the image forming means during image formation. This is repeated over a long period of time! Hard adhesion appears after IIJ rT+, and becomes even more difficult when an endless belt is used as the photoreceptor.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide an image forming apparatus in which the gap between the image carrying belt and the image forming means can be maintained constant at all times.

An object of the present invention is to structure the image forming means so that both image forming means have a degree of freedom relative to the gap forming means by holding the image forming means in a pair of independent holding parts. achieved by.

The present invention will be described below based on embodiments shown in the drawings.

Figures 1 to 3 show the entire image display device as an example of an image recording (forming) device, with Figure 1 being an external oblique view, Figure 2 being a perspective cross-sectional view, and Figure 3 being a vertical cross-section. It is a front view.

In the figure, 1 is a vertical device outer box, 2 is a display image viewing hole formed in the front panel of the outer box, and 3 (1
An operation panel with a lower part of the control board protruding forward and a VC installed on the upper surface; 4 is a display window glass placed in the window hole 2; 5, 6, 7
．． Reference numeral 8 denotes a belt support body, which is attached to the upper and lower parts of the outer box 1, respectively.
Consisting of four bearings arranged in parallel with each other with their axes running in the left-right direction of the outer box, and individually rotatably supported, an endless belt-type sensing body 9 (hereinafter abbreviated as a belt) ).

At both ends of the supporting rows 25, 6, 7, 8, there are sprocket wheels 10, 11° 12, +3 coaxially with the rollers.
(The rear end side is omitted) are provided, and a chain 14 that rotates in parallel with the belt 9 and is a drive transmission means for the belt is suspended around these sprocket wheels. This chain/14 and bell) are connected by a connecting means using a 9Vi elastic member system, and this point will be described later.

The belt 9 has, for example, a transparent sheet such as a polyester sheet as a base layer, a very thin layer of metal is vapor-deposited on the outer surface thereof to provide conductivity while substantially maintaining the transparency, and the metal-deposited surface side is provided with conductivity. Photosensitive material layer (photoconductive layer) such as CdS
It is entirely flexible and is suspended and supported by the above four rollers with the photosensitive material layer side facing outside.

Then, among the four rollers, roller 5 is used as a driving roller, and the rotational force of the motor M (Fig. 3) is transmitted to this roller, and at least one of the other three driven rollers, for example, roller 6, is , is provided as a belt tension roller to give tension to the suspended belt. As a result, the drive roller 5 is rotationally driven by the motor M in the counterclockwise direction in FIG. The belt 9 is rotated counterclockwise without any rotation. With this rotation, the outer surface of the belt between the rollers 5 and 8 (the outer surface of the belt on the tension side) moves from the bottom to the top and passes through the display surface image viewing hole 2 portion of the front panel of the outer box.

Reference numeral 24 denotes a laser beam scanning type image exposure means fixedly arranged inside the suspension belt 9, and includes a semiconductor laser oscillator 25. Polygon/mirror scanner 26, f-theta/z 2
7. Two thin exposure strips are placed in pressure contact with the inner surface of the track of the stretched belt section between the fixed reflector 28 and the two belt m-times support rollers 7°8 at the bottom of the device outer box, with moderate force. It consists of a roller 29.

This image exposure means 24 oscillates an intermittent laser beam L corresponding to time-series electric pixel signals outputted from an electric computer, image reading device, etc. from a semiconductor laser oscillator 25 toward a borigo/mirror scanner 26, and The laser beam LVi incident on the belt width direction VCm is incident on the inner surface of the belt portion between the rollers 7.8 on the path from the f-θ lens 27 to the reflecting mirror 28 and the exposure roller 29, and the inner surface of the belt portion is in the belt width direction. The laser beam is scanned in the direction. Then, this laser beam scanning is used as main scanning and the belt 9
The belt 9 is exposed to optical information light in the form of an image by a laser beam from the inner surface of the belt, with the zero-turn movement serving as a sub-scan.

Reference numeral 30 denotes a toner developing device disposed close to the outer surface of the belt portion between the rollers 7 and 8, and the structure of this toner developing device 30 will be described later together with the connection structure of the belt 9 and the chain/14.

Then, by operating the operation panel 3, when necessary conditions such as calling the surface image information and specifying the display position are set and a display start command is input, the rotation of the motor M causes the belt 90, which is a photoreceptor, to rotate at a predetermined speed. At the same time, the laser beam scanning exposure of designated image information to the belt 9 by the exposure means 24 is started on the inner side surface of the belt between the rollers 7.8. A toner developing device 30 is disposed on the belt outer surface side of the exposure section, and toner acts on the belt outer surface at the same time as exposure, so that toner images corresponding to the outer surface Vcll image of the belt 9 are sequentially formed. As the belt rotates, the toner image sequentially formed on the outer surface of the belt rotates from the bottom to the top of the display image viewing window on the front panel of the outer box and moves to the specified window hole range position. Then, the rotation of the -H belt 9 is stopped. As a result, an image is displayed in the window hole 2, and the image is visually recognized through the display window glass 4. Next, when the belt is rotated again by the belt re-rotation operation, the next display image moves to the window hole range position 7, and the next screen is displayed.

The image forming method in which optical information is applied to the belt from the inside without light and simultaneously developed from the outside is disclosed in Japanese Patent Application Laid-open No. 58-98746 and Japanese Patent Application Laid-Open No. 58-987 by the present applicant.
The disclosure is in No. 48, and the explanation here will be omitted.

The toner image on the outer surface of the belt after being displayed reaches the toner developing device 30 again as the belt rotates, where it is cleaned and removed by a developing brush, and immediately after this cleaning, it is newly subjected to simultaneous exposure and development. As a result, a new toner image is formed.

Now, the above is a general description of the image forming apparatus according to the present invention.Next, the configuration of the main parts will be described in detail.

First, the structure of the joint will be explained based on FIG. 4. In FIG.
One of the many link plates 14a making up the link plate 4 is provided with protrusions 15 that face each other and extend in the direction of the belt 9, and a flat elongated stay 16 is provided across the pair of opposing protrusions 15. The elastic member 18 is fixed to the middle part of the stay 16 so as to wrap around the stay 16, and extends from the elastic member 18 to the front and rear parts in the belt traveling direction. The end portions of the belt-shaped photoreceptor belt 9 are bonded to the thin plate portions 18a and 18bK, which have sufficient elasticity, using an adhesive or the like.

On the other hand, the connection with the stay 16 is made / Kuzurate 1
4 aK is adjacent to the front side of the chain/14 in the rotational direction,
A rectangular glue/kuzurate 14b with rounded corners is connected, and an ordinary link plate 14c is further connected by a bottle 19 next to it. Two rollers 22 and 23 are provided at the lower end (orbital outer end) 20 of this rectangular glue/straight plate 14b with a groove 1/21 at the rotation point. Note that the outer circumferences of the rollers 22 and 23 protrude 2 from the lower end 20.

Further, the lower part of the outer periphery of the roller 22 is provided so that the bend of the protrusion J5 protrudes from the lower surface and the lower surface of the thick portion 18c of the elastic member 18, and the roller 23t is located slightly above the roller 22. It is being

Next, the structure of the developing device will be explained based on FIGS. 5 and 6.

5 and 6, the above-mentioned developing device 30 includes a developing roller 31, a toner container 33 for storing toner 32, and a magnet 3 which is a component of the developing roller 31.
a motor 35 that rotates the magnet 34;
7, a left side plate 39 and a right side plate 40 that integrally support each of the above-mentioned members.

More specifically, the above-mentioned developing roller 31 that supplies toner to the belt 9 includes a cylindrical magnet 34 and a sleeve 47 that is disposed outside the rotating shaft 46 and the magnet 34 in a non-contact state. Of these, the magnet 34 is fixedly and integrally connected to the rotating shaft 46, and is rotatably connected to the sleeve 47 via a ball bearing 48.

Furthermore, at one end of the rotating shaft 46 (the left end in FIG. 6),
A driven pulley 37 around which the timing belt 38 described above is suspended is fixedly provided.

Support shaft portions 49.50 are formed in the sleeve 47 from both ends toward the outside in the axial direction, and these support shaft portions 49.50 are connected to the left side plate 39 and the right side plate 4 (
lζ is fitted. Note that one of the support shaft portions is fixed to one side plate. Further, spacer rollers 51 and 52 are fitted to the outer ends of the support shaft portions 49 and 50, and a plate grip 53 is provided with a stopper. Left and right side plates 39
, 40°0 opening, a bottom plate 54 is installed, and the toner 3
A hopper 33 for storing 2 is formed. This bottom plate 5
4 has a low rigidity such that the left and right side plates can rotate slightly independently around the fixed shaft 44.
9, 40 or as a separate part.
9 and 40 so that lζ is fitted.

On the other hand, rails 56 are attached to the left and right side plates 39, 40 at positions corresponding to the chains/14 by support columns 55. The rail 56 has a flat center portion 56a and a front end 5
6b and the rear end 56c form a slope.

These side plates 39, 40 and bottom plate 54 constitute a kind of box-shaped flexible unit, and the motor 35 rotates the magnet 34, and the rotational force of the motor is transmitted to the pulley 37 via the drive pulley 36. A timing belt 38 and the like for transmission are housed within this unit, and the entire flexible unit is rotatably supported by a fixed shaft 44 parallel to the developing roller 31 passing through both left and right side plates 39,40. There is.

Furthermore, compression springs 45 are provided between the developing side plates 39, 40 and the developing tray 410, and apply rotational force in the counterclockwise direction (FIG. 3) to each side plate 39, 40 independently. There is. Therefore, the spacer rollers 51 and 52 fitted to both ends of the sleeve 470 of the developing device 30 are connected to the exposure roller 29.
A gap d is formed between the belt 9 and the sleeve 470.

The exposure roller 29 is rotatably supported on a support plate 57 by a bearing 58, and this support plate 57 is attached to the apparatus outer box 1.
It is fixed to a U-shaped stay 59 provided between the holes.

Further, the stay 59 is provided with a pore 60 through which laser light passes.The structures of the joint portion and the developing portion are as described above, and their operations will be explained next.

As described above, in the developing device 30, the image lawn 31 of the spring 45 is normally aligned and stationary with a predetermined small gap d maintained relative to the belt 9. As the belt 9 passes through this small gap d, an image is formed on the belt surface.

On the other hand, after that, when the thick joint 18c of the belt 9 reaches this developing section, first, the rollers 23 on the chain 714 side come into contact with the center portion 56a of the rail 56 and push the rail 56 down. In conjunction with this pressing down, the developing device 30 moves to the fixed shaft 44.
It rotates clockwise around the axis (FIGS. 3 and 5), and is moved away from the developing roller 31 or the exposure roller 29. Thereafter, as the belt 90 runs, the rollers 23 come into contact with the slope 56b, while the rollers 22 come into contact with the center portion 56aK.

Therefore, the gap between the developing roller 31 and the exposing roller 29 is maintained sufficiently large until the thick joint portion 18c passes through.

First, after the thick joint 18c has passed through the developing section, the roller 22 separates from the slope section 56b, and the developing device 30Vi returns to the upward position by the restoring force of the spring 45, resulting in the state shown in FIG. Become.

In the developing device 30 of this embodiment, the developing roller 3 is installed between the side plates so that the side plates 39 and 40 can rotate somewhat independently of the fixed shaft 44 as the center of rotation of the developing device.
Since the bottom plate 54 and the like have a loosely fitted or flexible structure with respect to the side plates, and are each independently biased by compression springs 45, the gap d between the photosensitive belt 9 and the developing roller 31 can be maintained even after repeated operations over a long period of time. It is possible to always maintain a constant value.

That is, the gap d between the photosensitive belt 9 and the desk image roller 31 is determined by the radius of the spacer rollers 51 and 52, and the accuracy of the developing unit 30 does not affect the gap dK. Therefore, even if the assembly accuracy of the developing device unit 30 is slightly poor, or even if the developing device unit 30 is slightly twisted due to repeated operations over a long period of time, the spacer rollers 51. Ri2
As long as the accuracy of the image roller 31 is good, the gap d can be
This makes it possible to always guarantee a constant value over the thrust direction). Further, even when the developing device unit 30 is taken out of the machine for cleaning or maintenance and then set back into the machine, images can be produced immediately without adjusting the gap between the photosensitive belt 9 and the developing roller 31. Deheru.

The above is a description of one embodiment of the image forming apparatus according to the present invention, but it goes without saying that the present invention is not limited to this embodiment.

For example, in this embodiment, an image display device is used as the image forming device. Furthermore, it is applicable to image forming apparatuses having a function of transferring onto transfer paper or the like.

In history, in addition to those using laser scanning optical systems as exposure means, exposure means such as light emitting dimer arrays, liquid crystal shutter arrays, and exposure means used in copying machines that expose light reflected from Vi originals have been used. May be used.

Furthermore, the structure of the developing device 30 can be changed in various ways, and the developing device 30 may be moved up and down in the vertical direction.

As described above, the image forming apparatus according to the present invention has a structure in which the image forming means is movably held on the side of a pair of independent holding parts and has a degree of freedom with respect to the gap forming means. Since the deviation of the means is absorbed, there is an effect that the gap between the image bearing belt and the image forming means is always kept constant.

[Brief explanation of the drawing]

Fig. 1 is an external perspective view of the image display device, Fig. 2 is a cross-sectional perspective view, Fig. 3 is a vertical cross-sectional view, Fig. 4 is a perspective view showing a part of the chain configuration, and Fig. 5 is a perspective view of the image display device. A perspective view of the developing device, and FIG. 6 is a sectional view of the developing roller. 9... Endless belt type photoreceptor belt (image bearing belt),
14°° Chain, 14a, 14b, 14c...' Link plate, 16... Stay, 18... Elastic part (joint part), 22.23... Roller (biasing means), 29
...Lightning roller, 30・Developer (image forming means), 3
1... Developing roller, 39, 40... Side plate (holding member), 42. 43... Support plate, 44... Fixed shaft, 45
... Compression spring (gap forming means), 51.52... Spacer roller (gap forming means), 54... Bottom plate, 56.
...Rail, 57...Support plate (gap forming means) Fig. 3

Claims (2)

[Claims] (1) In an apparatus comprising an endless image carrying belt having a joint part and forming an image on one carrying part of the image carrying belt by passing the image forming means through an image forming means, the image forming apparatus a pair of independent retainers A for holding the means Vζ in an operable manner; and a pair of retainers A for retracting the image forming means out of the approach path of the joint in response to the joint entering the image forming area. A biasing means on the image carrying belt side, and a gap forming means that acts to form a gap between the image forming means and the image holding bevel. , an image forming device comprising an image bearing belt. (2) The gap forming means includes an elastic body that restores the image forming means from the retracted position, and a fixing member that prevents the image forming means from restoring. An image forming apparatus equipped with the image carrying belt described in VC. 2.) An image forming apparatus comprising the imager carrying belt according to item 1.