JPH03149587A - Color image forming device - Google Patents

Abstract

PURPOSE:To use a device in a long term by positioning and sticking the leading end part of a belt in a belt-like image forming body moving direction under the trailing end part of the belt and making a cleaning means provided with an abutting and releasing mechanism oppose to the image forming body moving direction. CONSTITUTION:The leading end part E1 of the belt in the belt-like image forming body 1 moving direction is stuck after being positioned under the trailing end part E2 of the belt, and the cleaning direction of the cleaning means 13 provided with the abutting and releasing mechanism is opposed to the belt- like image forming body 1 moving direction. Thus, there is no chance that a blade 13A abuts on the stuck part of a photosensitive belt 1, so that the blade 13A and the photosensitive belt 1 are not damaged, and also the conveying performance is not reduced even in the case that a sheet-like elastic member is used as the blade 13A, and an effective cleaning action can be obtained in a long term.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a color image in which a toner image is formed on a belt-like image forming member by an electrophotographic method and transferred onto a transfer material to obtain an image. The present invention relates to a forming device.

[Background of the invention]

There are many ways to obtain color images using electrophotography.
A device has been proposed. For example, JP-A-61-10077
As disclosed in Publication No. 0, a latent image is formed and developed in accordance with the number of separated colors of an original image on a photoreceptor drum serving as an image forming member, and is transferred onto a transfer drum each time the development is performed. There is a method of forming a multicolor image on a paper and then transferring it onto recording paper to obtain a color copy. A device using this method requires a transfer drum large enough to transfer one sheet of image onto its circumferential surface in addition to the photoreceptor drum, and the device does not have a large and complicated structure. Inevitable.

For example, as disclosed in Japanese Patent Laid-Open No. 61-149972, a latent image is formed and developed on a photoreceptor drum according to the number of separated colors of the original image, and is transferred onto a transfer material each time it is developed. This is a method of obtaining multicolor copies. With this method, it is difficult to overlay multicolored images with high precision.
It is not possible to obtain a good quality color copy.

Another method is to repeatedly form a latent image on a photoreceptor drum according to the number of separated colors of an original image and develop it with color toner, and then overlap the color toner images on the photoreceptor drum and then transfer the images to obtain a color image. The basic process of forming a multicolor image is disclosed in Japanese Patent Application Laid-open No. 60-75850 and No. 60-7 by the present applicant.
No. 6766, No. 60-95456, No. 60-9545
No. 8, No. 60-158475, etc.

In a multicolor image forming apparatus that obtains a color image through such superimposition, a plurality of developing units containing different color toners are arranged around the periphery of the photoreceptor drum. The photoreceptor drum is rotated multiple times to develop the latent image on the photoreceptor drum to obtain a color image.

As for image forming bodies, as explained above, there are photosensitive drums with a photoconductor coated or vapor-deposited on the circumferential surface of the drum, and belt-shaped image forming bodies with a photoconductor coated or mounted on a flexible belt. has also been proposed. The shape of the belt-shaped image forming body (hereinafter also referred to as a photoconductor belt) is determined by stretching it between rotating rollers including a drive roller, so it is possible to effectively utilize space and create a compact color image forming apparatus. It is effective when configured. Also, since the photoreceptor belt can run along a small curvature,
By using a rotating roller with a small diameter and separating the transfer material using this curvature, it is also possible to prevent poor separation of the transfer material.

[Purpose of the invention]

Such a belt-like image forming member is a thin sheet-like photoreceptor with a bent conductive layer between a substrate and an organic photoreceptor layer, and since it is used in an endless form, its production requires a lot of effort. A method of obtaining a ring-shaped photoreceptor by forming the photoreceptor into a cylindrical shape by casting and cutting it into the required width has also been used, but there are problems in practice. The thickness of the photoreceptor is extremely thin, about 0.101 mm, and requires precision in thickness, so it is technically difficult to mold it, and it is quite difficult to obtain a belt-shaped image forming member of satisfactory quality. It was considered difficult.

On the other hand, attempts have also been made to create an endless photoreceptor by bonding the ends of a sheet-like photoreceptor produced using a stretched thin film, etc., but this method results in a difference in level due to the adhesion of the ends. This cannot be avoided, and therefore it is not only inappropriate to form an image on the bonded material, but also cause the photoreceptor to slip due to contact with the cleaning member, and in extreme cases, the bonded material may peel off. This has caused problems in terms of durability.

The present invention solves and improves this point, and as a result, even when elastic cleaning is applied to a belt-shaped image forming body formed by bonding, it can be used for a long period of time without impairing its conveyability or durability. The object of the present invention is to provide a color image forming apparatus that can be used in various situations.

[Structure of the invention]

The above object is a color image forming apparatus in which a belt-like image-forming body, in which the belt ends are bonded vertically, is stretched between a plurality of rotating rollers, and a toner image is formed by overlapping the belt-like image-forming body on the belt-like image-forming body. In the above, the belt-like image forming body is bonded to each other in the moving direction l, with the leading end of the belt at the bonding portion located below the rear end of the belt, and the cleaning means has an abutting/releasing mechanism. This is achieved by a color image forming apparatus characterized in that the cleaning direction of the cleaning means is opposite to the moving direction of the belt-like image forming member.

〔Example〕

An embodiment of the color image forming apparatus of the present invention is shown in FIGS. 1 to 3.

In FIG. 1, l is a flexible photoreceptor belt which is a belt-like image forming member, and the photoreceptor belt l is installed between a rotating roller 2 made of a rubber roller and a rotating roller 3 made of a metal roller. and is conveyed clockwise by the rotation roller 2.

Reference numeral 4 denotes a guide member that is inscribed in the photoreceptor belt l, and the photoreceptor belt l is brought into a tensioned state by the action of the tension roller 5 that is urged outward, so that its inner circumferential surface is guided by the tension roller 5. The member 4 is rubbed.

Therefore, the photoreceptors on the outer circumferential surface of the photoreceptor belt 1 are always maintained at a constant position relative to the surface of the guide member 40 even during conveyance, making it possible to form a stable image forming surface.

6 is a scorotron charger which is a charging means; 7 is a laser writing system unit which is an image exposure means; and 8 to 11 are developing devices which are a plurality of developing means each containing a developer of a specific color. is arranged at a position facing the guide member 4 of the photoreceptor belt l. In order to maintain a gap without interfering with the movement of the photoreceptor belt 1, the guide member 4 is brought into contact with the guide member 4 on the outside of the photoreceptor belt 1 with a gap maintaining means.

In addition to the optical system shown in the drawings, the laser writing system unit may also include an optical system that integrates a light emitting section and a convergent light transmission body.

Each of the developing units 8.9 and 10.11 is for example yellow.

The developing sleeves 8A, 9A, IOA, and LLA each accommodate magenta, cyan, and black developers and maintain a predetermined gap with the photoreceptor belt 1, and the latent image on the photoreceptor belt 1 is provided. It has the function of converting into a head image using a non-contact development method. Unlike contact development, this non-contact development has the advantage of not interfering with the movement of the photoreceptor belt.

Reference numeral 12 denotes a transfer device, 12A denotes a static elimination bar, and 13 denotes a cleaning device as cleaning means, in which a blade 13A and a toner collecting roller 13B are kept at a position apart from the surface of the photoreceptor belt 1 during image formation. Only during post-transfer cleaning, it is pressed against the surface of the photoreceptor belt l as shown.

The process of forming a color image by the color image forming apparatus 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. In other words, the color image data input section (Figure 2 (a)) where the image sensor scans the original image.
) is processed in the image data processing section (Figure 2 (B)) to create image data, which is temporarily stored in the image memory (Figure 2 (C)). . Then, the image memory is taken out at the time of recording and sent to the recording section (FIG. 2 (d)).
For example, the image data is input to the color image forming apparatus shown in the embodiment of FIG.

That is, when a color signal output from an image reading device separate from the printer is input to the laser writing system unit, a laser beam generated by a semiconductor laser (not shown) is driven in the laser writing system unit. The peripheral surface of the photoreceptor belt l is rotated and scanned by a polygon mirror 78C rotated by a motor 7A, the optical path is bent by mirrors 7D and 7E via an fθ lens 7C, and the peripheral surface of the photoreceptor belt l is charged in advance by a charger 6 serving as a charging means. It is projected upward and forms 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 photoreceptor belt l. Therefore, a latent image corresponding to the first color is formed on the circumferential surface of the photoreceptor belt l by the main scanning by the laser beam and the sub-scanning by the conveyance of the photoreceptor belt l. This latent image is reversely developed in a non-contact state by a developing device 8 loaded with yellow (Y) toner (developing medium) of the developing means, and a toner image is formed on the belt surface. The obtained toner image, while being held on the belt surface, passes under a cleaning device 13, which is a cleaning means, which is separated from the circumferential surface of the photoreceptor belt 1, and enters the next copy cycle.

That is, the photoreceptor belt l is charged again by the charger 6, and then the second color signal outputted from the signal processing section is input to the writing system unit, and the second color signal is inputted to the writing system unit, and the second color signal is then charged again by the charger 6. In the same manner, writing is performed on the drum surface to form a latent image. The latent image is reversely developed in a non-contact manner by a developing device 9 loaded with toner of magenta (CM) as the second color.

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

IO is a developing device having cyan (C) toner, and forms a cyan (C) toner image on the belt surface based on a control signal generated by a signal processing section.

Further, numeral 11 denotes a developing device having black toner, which forms a black toner image superimposed on the drum surface using the same momentum. Direct current or even alternating current bias is applied to each of the sleeves of these developing devices 8°9, 10, and 11, and jumping development is performed using l component or 2 component 5 developer, which is the developing means, and the substrate is grounded. Reversal development is performed on the photoreceptor belt l in a non-contact manner.

The color toner image thus formed on the circumferential surface of the photoreceptor belt 1 is transferred to a transfer material fed from the paper feed force set 14 via the paper feed guide 15 at the transfer section.

That is, the transfer material housed in the paper feed force set 14 is conveyed by the rotation of the paper feed roller 16, and the top layer is conveyed through the timing roller 17 to the transfer device in synchronization with the image formation on the photoreceptor belt l. It is supplied to the 12° static elimination bar 12A.

The transfer material that has undergone image transfer and charge removal is reliably separated from the photoreceptor belt l, which suddenly changes direction along the rotating roller 2, without being affected by image quality such as toner scattering due to the charge removal effect. After the image is fused by the fixing roller 18, the sheet is discharged onto the tray 20 via the discharge roller 19.

On the other hand, the photoreceptor belt l, which has completed the transfer to the transfer material, continues to be conveyed, and a blade 13A facing the rotating roller 3 and a toner collection roller 13B consisting of a rotating sponge member
The remaining toner is removed in the cleaning device 13 which is brought into pressure contact with the blade 13A, and after the cleaning is finished, the blade 13A is separated again, and a little later, the toner collection roller 13B is separated and a new image forming process begins.

The photoreceptor belt l has a thickness of 30 to 1 mm as shown in FIG.
00 μm pET (polyethylene tereftate) is used as the substrate IA, and an OPC layer (c) with a thickness of 10 to 30 μm consisting of a charge generation layer and a charge transfer layer is applied as a photoreceptor layer with a conductive layer IB sandwiched thereon. A sheet of photoreceptor with a total thickness of about 0.1 m is cut into a specific shape and the ends are pasted together to form a ring. It is stretched and conveyed endlessly in the direction of arrow A.

With respect to the moving direction of the photoreceptor belt L, that is, the direction of arrow A, the belt leading end El is overlapped with the belt rear end E2 within a range of 0.3 to 3 m from the inside of the ring, and is connected by ultrasonic bonding. There is.

Further, the edge of the belt rear end E2 is obliquely chamfered, and the conductive layer IB exposed at the chamfer is sealed with a high-resistance sealant.

However, in the method of forming an endless photoreceptor by ultrasonically bonding the ends of a sheet-like photoreceptor to each other, it is impossible to avoid the formation of a level difference due to the adhesion of the ends. Not only is it unsuitable to form an image, but contact with the cleaning member may cause damage to the cleaning member, the photoreceptor may slip, or in extreme cases, the bond may peel off, reducing durability. There is a problem with this point.

This is because the cleaning means acts in a direction opposite to the moving direction of the photoreceptor. When the tip of the blade 13A is arranged toward the upstream side in the moving direction of the photoreceptor as shown in the figure, the bonded portion at the rear end of the belt should be placed at the tip of the belt so that the tip of the blade does not get wedged in the step of the bonded portion. It needs to be configured so that it is above the bonded part.

If the pasting is done in the opposite direction, the above problem will be exacerbated.

On the other hand, if the tip of the blade 13A is disposed toward the downstream in the direction of movement of the photoreceptor, the degree of the above problem is reduced, but the cleaned toner is difficult to be discharged from the upper surface of the blade, resulting in a decrease in cleaning performance. occurs.

Therefore, when using the blade 13A, the photoreceptors are bonded together with the leading end of the belt at the bonding portion positioned below the rear end of the belt in the moving direction, and the blade 13A
It is preferable that the tip abuts toward the upstream side.

Of course, when forming a toner image of each color, the timing of image formation with respect to the conveyance cycle of the photoreceptor belt I is controlled so that the above-mentioned bonded portion is not located within the screen.

On the other hand, the blade 131 and the toner conveying roller 13B, which are the cleaning means of the cleaning device 13, are as follows:
It has a function that allows it to come into contact with and release from contact with the photoreceptor belt l, and the toner releases contact and retreats from the circumferential surface of the photoreceptor belt l during image formation and superimposition. After the toner image has been transferred, the contact state is brought into contact only when the residual toner faces the image surface, and the contact state is immediately returned to the released state after passing the image surface.

In particular, at the belt bonding portion, the blade 13A has already been released, while the toner collection roller 13B has been released from the blade 1.
It is preferable that the pressure contact state is released after the belt passes through the bonding portion in order to remove the toner accumulated on the belt 3A.

In this way, both blades 13A have no chance of coming into contact with the above-mentioned bonded portion of the photoreceptor belt l, and even if a plate-shaped elastic member is used for the blade 13A, further damage may occur to the blade 13A and the photoreceptor belt l. It is possible to obtain an effective leaning action without causing any damage or deterioration of its transportability.

Figure 4 shows another embodiment, in which a fur brush 113A with bristles implanted in the cylindrical part is used as a retractable cleaning means, or a cylinder with a magnetic force inside is rotated, and iron powder is applied to the surrounding area by the magnetic force. Magnetic brush (2
13a) is rubbed against the photoreceptor belt 1, and cleaning is performed by contacting the photoreceptor belt 1 with a brush. In this case as well, the fur brush l13A
Alternatively, by rotating the magnetic brush 213A in a counter direction with respect to the moving direction of the photoreceptor belt 1 as shown in the figure, the bonded portion of the photoreceptor belt 1 can be cleaned without any problem. In addition, 113 on the diagram
B is a toner adsorption roller, and a fur brush l13
This is a roller that electrostatically attracts and removes the toner cleaned by A or the magnetic brush 213A.

〔Effect of the invention〕

The zero invention was to put into practical use a high-quality belt-shaped image forming body using a simple manufacturing method, and to make it possible to use a more powerful leaning method.As a result, it was possible to produce a compact, low-cost, high-quality color image. obtained. A color image forming apparatus is now provided.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram of a color image forming apparatus of the present invention, FIGS. 3 and 4 are views of its main parts, and FIG. 2 is a block diagram showing an image forming system.

Claims (2)

[Claims] (1) In a color image forming apparatus in which a belt-like image forming body with belt ends stuck together vertically is stretched between a plurality of rotating rollers, and a toner image is formed by overlapping the belt-like image forming body on the belt-like image forming body. The belt-shaped image forming body is bonded together with the leading end of the belt at the bonding portion positioned below the rear end of the belt in the moving direction, and the cleaning means is in contact with and
1. A color image forming apparatus, comprising a release mechanism, and a cleaning direction of said cleaning means is opposite to a moving direction of a belt-shaped image forming member. (2) The color image forming apparatus according to claim 1, wherein the cleaning means is a plate-shaped elastic member, and a tip of the plate-shaped elastic member abuts toward the upstream side.