JPH03100569A - Color image forming device - Google Patents

Abstract

PURPOSE:To automatically clean a wire in an appropriate cycle by incorporating a wire cleaning device in an electrifier and operating this wire cleaning device by means of attaching and detaching the paper feed part of a paper feed cassette. CONSTITUTION:A scorotron electrifier 6 is disposed opposite to the outer periphery of a photosensitive belt 1 behind a guide member 4, as well as a laser write system unit 7, plural developing units 8 to 11, etc. The scorotron electrifier 6 is composed of a discharge electrode device housing an electrifying wire and a grid 6B disposed in front of the electrode device. The electrode device incorporates the wire cleaning device which is automatically operated by removing the paper feed cassette 14 from a device main body. Thus, the electrifying wire of the electrifier 6 is automatically cleaned in an appropriate cycle.

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 color image forming apparatus, and particularly to a color image forming apparatus equipped with a charger incorporating a wire cleaning device.

[Background of the invention]

There are many ways to obtain color images using electrophotography.
A device has been proposed. For example, Japanese Patent Publication No. 61100770
As disclosed in the publication, a latent image is formed and developed in accordance with the number of separated colors of the original image on a photosensitive drum serving as an image forming member, and is transferred onto a transfer drum each time it is developed. There is a method of forming a multicolor image 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 overlap multicolor images with high precision, and it is impossible to obtain high-quality color copies.

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, 60-! This is disclosed in Japanese Patent No. 58475 and the like.

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.

Regarding image forming bodies, as explained above, there are photosensitive drums in which a photoconductor is coated or deposited on the drum circumference, as well as belt-shaped image forming bodies in which a photoconductor is coated or mounted on a visible belt. 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.

[Purpose of the invention]

A scorotron charger in which a grid is disposed near the surface of the photoreceptor is used for a photoreceptor such as an OPC, which is an image forming member, in order to apply a negative potential regardless of the presence or absence of toner on the photoreceptor layer or previous charging.

However, in the above-mentioned image forming apparatus that forms a color image by superimposing a color image, charging occurs from the top of the toner image, so the grid and charger wire are easily contaminated, and if the wires of the charger become dirty, uneven discharge may occur. becomes impossible. Particularly when the charger is installed below the photoreceptor, the dirt is particularly noticeable.

As for the wire of the charger, a charger with a built-in wire cleaning device is already available, and dirt can be cleaned while the wire is attached to the main body of the device.

However, in the conventional method of cleaning the wire of the charger, it is operated arbitrarily by pressing a manual button etc. between copies, etc., so the interval is not constant, and sometimes people forget to operate the wire even though it is necessary to clean it. There was a problem in maintaining the charging performance in the best condition.

In order to solve this problem, Japanese Patent Application Laid-open Nos. 62-86375 and 61-29 related to automatic cleaning of electrodes or its control.
Although methods such as those disclosed in Japanese Patent No. 2655 have been proposed, they have not yet provided fool-proof automatic cleaning for users.

The present invention solves this problem and improves the image forming apparatus, thereby providing a color image forming apparatus that can automatically perform wire cleaning at appropriate intervals without requiring any special operations.

[Structure of the invention]

The above object is to produce a color image by disposing a scorotron charger having at least a plurality of developing devices, a grid, and a charging wire around the periphery of a belt-like image forming body that moves while being stretched between two rotating rollers. This is achieved by a color image forming apparatus characterized in that a wire cleaning device provided in the scorotron charger is activated by an operation of attaching and detaching a paper feed cassette to and from a paper feed section.

〔Example〕

An embodiment of the color image forming apparatus of the present invention is shown in FIGS. 1 to 9.

In FIG. 1, l is a visible photoreceptor belt that is a belt-like image forming member, and the photoreceptor belt l is installed between rotating rollers 2 and 3, and is driven by the rotating roller 2, which is a rubber roller. Transported clockwise.

Reference numeral 4 denotes a guide member fixed to the main body of the apparatus so as to be inscribed in the photoreceptor belt 1, and the photoreceptor belt 1 is brought into tension by an upward mechanical action of the tension roller 5, so that its inner circumferential surface is rubbed against the guide member 4.

Therefore, the photoreceptors on the outer circumferential surface of the photoreceptor belt 1 are always maintained in a fixed position relative to the surface of the guide member 4 even during conveyance, making it possible to form a stable image forming surface.

Reference numeral 6 denotes a scorotron charger as a charging means, 7 a laser writing system unit as an image exposure means, and 8 to 11 a plurality of developing means, that is, developing devices, each containing a developer of a specific color. The means is disposed facing the outer peripheral surface of the photoreceptor belt l with the guide member 4 on the back side.

In addition to the optical system shown in the drawings, the laser writing system unit 7 may also include an optical system that integrates a light emitting section and a convergent light transmission body.

The developing units 8.9.10.11 contain, for example, yellow magenta, cyan, and black developers, respectively, and each of the developing sleeves 8A, 9A, IOA, and 11A maintains a predetermined gap with the photoreceptor belt 1. and a photoreceptor bell l-
It has a function of making the latent image on 1 visible using a non-contact development method. This non-contact development differs from contact development in that it does not interfere with the movement of the photoreceptor belt.

12 is a transfer device, 12A is a static elimination bar, 13 is a cleaning device, and the blade 13A and toner conveying roller 13B of the cleaning device 13 are kept at a position apart from the surface of the photoreceptor belt (2) during image formation, and after image transfer. Only during cleaning, it is pressed against the surface of the photoreceptor belt 1 as shown in the figure.

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 by the image data processing section (FIG. 2 (b)) to create image data, which is then stored in the image memory (FIG. 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 7, the laser writing system unit 7 outputs a laser beam generated by a semiconductor laser (not shown). is rotated and scanned by a polygon mirror 7B rotated by a drive motor 7A, and passes through an fθ lens 7C to mirrors 7D and 7E.
The optical path is bent by this, and the light is projected onto the circumferential surface of the photoreceptor belt l, which has been charged in advance by a charger 6 serving as a charging means, 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 photoreceptor belt 1. Therefore, during the main scanning by the laser beam and the sub-scanning by the conveyance of the photoreceptor belt l, the photoreceptor belt l is
A latent image corresponding to the first color is formed on the peripheral surface of =1. This latent image is created using yellow (Y) toner (
The toner image is developed by the developing device 8 loaded with a developing medium (developing medium), 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 peripheral surface of the photoreceptor belt 1, and enters the next copy cycle.

That is, the photoreceptor belt 1 is charged again by the charger 6, and then the second color signal output from the signal processing section is input to the writing system uni-node 7, and the above-mentioned first color signal is Writing is performed on the drum surface in the same manner as in the case of the drum surface, and a latent image is formed. The latent image is developed by a developer 9 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.

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 the signal processing section C.

Further, numeral 11 denotes a developing device having black toner, which forms a black toner image superimposed on the drum surface by the same process. These developing devices 8, 9° IO and 11
DC or even AC bias is applied to each sleeve, and jumping development is performed using a two-component developer as a developing means, and the photoreceptor bell I-1 whose base is grounded
Development is now possible without contact. Note that for development, non-contact development using an l-component developer can also be used.

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

That is, the top layer of the transfer material stored in the paper feed cassette 14 is carried out by the rotation of the paper feed roller 16, and transferred to the transfer device 12 via the timing roller 17 in synchronization with the image formation on the photoreceptor belt l. supplied to.

The transfer material that has undergone image transfer and static electricity removal is transferred to the rotating roller 2.
The image is reliably separated from the photoreceptor belt l, which suddenly changes direction along the direction, and moves upward, and after the image is fused by the fixing roller 18, it is ejected onto the tray 20 via the ejection roller 19.

On the other hand, the photoreceptor bell l-1, which has completed the transfer to the transfer material, continues to be transported and is moved by the blade 13^ and the toner transport roller 13.
The remaining toner is removed by the cleaning device 13 with the blade B in pressure contact, and after the cleaning is finished, the blade 13A is separated again, and a little later, the toner supply roller 13B removes the toner accumulated on the tip of the blade 13A. After that, the toner supply roller 13B is separated and a new image forming process begins.

The photoreceptor belt 1 is incorporated together with the cleaning device 13 into a process cartridge 30 as shown in FIG. 3, and is attached to and removed from the main body of the apparatus as an independent unit.

That is, in the process cartridge 30, the bearings support the rotary rollers 2 and 3, on which the photoreceptor belt 1 is stretched between the front and rear substrates 30A and 30B, which are integrated by two stays 31 and the guide member 4. Furthermore, a cleaning device 13 is sandwiched and supported at a position facing the circumferential surface of the rotating roller 3.

The guide member 4 has a part of its volume connected to the toner collection container 4.
A, the toner removed from the circumferential surface of the photoreceptor belt l in the cleaning device 13 is transferred to the toner transport pipe 4B.
It is designed to be transported and collected via the

The process cartridge 30 has each substrate 3OA and 30B.
A pair of retaining holes H are provided that pass through the device body, and the device is mounted on the device body by engaging with a pair of support shafts protruding from the device body side.

On the other hand, the scorotron charger 6 is composed of a discharge M and IL pole device 6A that accommodates a charging wire, and a grid 6B disposed in front of the device. The discharge electrode device 6A is attached to the main body of the device, while the grid 6B is attached to the process cartridge 30 side.

FIG. 4 is an exploded view of the essential parts of the process cartridge 30 in the plane shown in the direction of the arrow in FIG.

Reference numeral 60 in FIG. 4 denotes a protective cover that covers the photosensitive surface of the photosensitive belt l in contact with the guide member 4.

It is fixed by adhesive or the like to the raised portion 4C of the guide member 4 while being slightly spaced apart from the photosensitive surface to protect the photosensitive surface.

The protective cover 60 has rectangular holes 60A, 60B, and 60C opened in the portions facing each of the image forming means described above, so that the image forming process by each image forming means is performed with the protective cover 60 attached.・61 is the square hole 6
Grid attachment members are fixed to both ends of the grid attachment member 61 by adhesive or the like, and a grid wire is wound around the protrusion on the grid attachment member 61 to form the grid 6B.

FIG. 5 shows the structure of the discharge electrode device 6A.
60 is a back plate that also serves as a chassis, 161A and 161B are electrode blocks attached to both ends of the back plate 160, and 162 is the electrode block 161A and 1
A pair of charging wires are stretched between the wires 61B and 61B.

The electrode device 6A has a built-in wire cleaning device. As a wire cleaning device, the patent application filed by the applicant in 1983-28
The technical measures according to document No. 8371 are used. 163
164 is the shaft 16 of the main slide piece 163. 164 is a main slide piece that can slide in the left-right direction by engaging with a slit-shaped guide groove 160A provided in the back plate 160.
Rotatably supported on 3A 1. It is a sub-piece.

The sub-piece 164 projects from four square columns 164B, and by rotating clockwise about the shaft 163A, each square column 164B can be brought into pressure contact with the charging wire 162.

The main slide piece 163 and the sub-piece 164 are connected to the guide groove 1 by a gear device incorporated in the electrode pro 7 slide 161A.
60A.

The gear device is composed of a worm W connected to a power shaft, a utility gear Gl that is integrated with a worm gear that meshes with the worm W, and a gear G2 that meshes with the gear Gl.

The gear G2 has an endless drive wire 165 wound around a pulley P provided on an electrode block 161B on the opposite side around a coaxially integrated cylinder S a plurality of times to create a tensioned state, and parallel drive wires 1.65 One side is clamped to the bottle 164A on the sub-piece 164.

When the main slide piece 163 is not cleaning, it is located on the electrode block 161B side as shown by the broken line and is retracted to the outside of the maximum effective screen width on the photosensitive surface. Sub piece 1
64 is slightly rotated in the counterclockwise direction, and as a result, each of the square columns 164B is released from pressure contact with the charging wire 162 and is maintained at an angle apart from the charging wire 162.

The wire cleaning device is automatically activated when the paper feed cassette 14 is removed from the main body of the device.

FIG. 6 is an explanatory diagram showing the relationship between the operation of the paper feed force cellar 1-14 and the operation of the cleaning device. The paper feed cassette 14 is mounted parallel to the back of the apparatus main body from the front surface thereof, and is inserted from the position shown by the dotted chain line to the position shown by the solid line in the figure.

Upon insertion, the paper feed cassette 14 passes through each optical path of a pair of 7 sensors SA and SB arranged in the main body of the apparatus using a light shielding plate 14A protruding from the side in the order of 7 sensors 5A = 7 sensors SB, but when the signal is received, the control is performed. The function of the section keeps the power source of the cleaning device in a stopped state.

On the other hand, when taking out the attached paper feed cassette 14 from the apparatus, the light shielding plate 14A is held by the photo sensor S.
Photosensor 5B-7 Otosensor S connects each optical path of B and SB.
By completing the sequence A, the power source of the cleaning device starts operating according to the function of the control section.

During cleaning, the gear device is activated by the rotation of the power shaft, and the gear G2 rotates the cylinder S in a counterclockwise direction.

Therefore, the main slide piece 163 is connected to the drive wire 165.
The sub-pieces 164 begin to slide to the left due to the traction force, and at the same time the sub-pieces 164 are urged clockwise.
B is pressed against the charging wire 162 and rubbed against the charging wire 16
Toner and foreign matter adhering to 2 are removed and cleaned.

Thus, in the scorotron charger 6 provided in the color image forming apparatus of this embodiment, the grid 6B is operated in a state in which the cartridge 30 is removed from the apparatus main body, while the charging wire 6B is operated in a state in which it is attached to the apparatus main body. By taking out the paper feed cassette 14, each can be cleaned.

The main slide piece 163 slides from the position shown by the broken line in FIG. 5 to the position shown by the solid line, and then is reversed by the reverse rotation of the power source and returns to the position shown by the broken line again to stop its operation.

Further, the charging wire can be cleaned by mechanically transmitting the operation associated with attaching and detaching the paper feed cassette to and from the main body of the apparatus.

In this case, the discharge electrode device 206A having the structure shown in FIG. 7 or FIG. 8 which is a plan view of the main part thereof is used.
The charging wire 262 is cleaned when it is taken out from the main body of the apparatus No. 14.

The discharge electrode device 206A has a built-in main slide piece 263 and a sub-piece 264 of the same type as the discharge electrode device 6A described above as a wire cleaning device, but one end of the sub-piece 264 is connected to the length of the side of the back plate 260. It penetrates the hole and protrudes to the outside.

- A pair of guide shafts 301 installed in the front and back direction of the blade device main body
A slidable driving member 300 is attached to the arm 300A, which projects above the arm 300A, which holds the sub-piece 264 projecting from the back plate 260.

Further, a reel 302 that is urged to rotate in one direction by a torsion spring 302A is supported by a shaft on the inner wall of the device main body, and one end of a drive wire 303 wound around the reel 302 is attached to a protrusion 300B of the drive member 300. Fixed.

When the paper feed cassette 214 is not attached to the apparatus main body, the driving member 300 slides toward the front side of the apparatus main body due to the rotation of the reel 302, and slides the protrusion 300C.
- It is stopped in contact with the collar 304.

In this position, the sub-piece 264 is urged to rotate slightly clockwise, so that each of the square columns 264B is in pressure contact with the charging wire 262.

When the protrusion 300C is pushed in by mounting the paper feed cassette 214 and the driving member 300 slides toward the back of the apparatus main body, the sub-piece 264 is biased to rotate slightly counterclockwise, so that each square column 264B In both cases, the torsion spring 3 of the reel 302 is released from pressure contact with the charging wire 262 and reaches the position shown by the broken line while maintaining the separated angle.
The installation of the paper feed cassette 214 is completed with 02A in the stored state.

Therefore, after completing the required copying, the paper feed cassette 214
When the reel 302 is taken out from the main body of the apparatus, the reel 302 rotates in the opposite direction due to the release of the stored force of the torsion spring 302A, and the driving force returns the driving member 300 to the initial position.

As a result, the sub-piece 264 is also returned to the position shown by the solid line, but at this time it is urged to rotate slightly clockwise, so that each of the square columns 264B presses against the charging wire 262 and moves while sliding. Toner and foreign matter adhering to the charging wire 262 are automatically removed and cleaned.

FIG. 9 shows the photoreceptor bell l- of each image forming means involved in the color image forming apparatus equipped with the discharge electrode device 6A shown in FIG.
This shows the setting of the relative position with respect to 1, and when using the discharge electrode device 206A shown in FIG. 8, the position is set in exactly the same way.

The main part of the charging means is shown in FIG. 9(A) with the cross section indicated by arrow AA, the main part of the developing means is shown in FIG. 9(B) with the cross section shown by arrow BB, and the image exposing means is shown in FIG. 9(B). An optical system having a convergent light transmitting body instead of the optical system is shown in FIG. 9(C) with a similar cross section.

In FIG. 9(A), the grid 6B is directly attached to the guide member 4 via the above-mentioned protective cover 60 and grid attachment member 61, so that a highly accurate position relative to the photosensitive surface of the photosensitive belt I can be maintained.

On the other hand, regarding the discharge electrode device 6A, the electrode block 161A
and 161B are respectively formed with protrusions T, and the protrusions T are formed on the guide member 4 on the outside of the grid 6B.
It is urged by an elastic member 166 such as a leaf spring so as to come into pressure contact with.

Therefore, the charging wire +62 of the electrode device 6A can also be set to maintain a highly accurate position with respect to the photosensitive surface of the photoreceptor belt l, and as a result, the photoreceptor can be reliably charged to a predetermined potential. .

Further, in FIG. 9(B), 9A is a developing sleeve of the developing device 9, and 9B is an abutting roller serving as an abutting member.
A bearing B is rotatably supported by the rotating shaft 9C of the developing sleeve 9A.

If the circumferential surface of the developing sleeve 9A or the photoreceptor belt l
The developing sleeve 9A has an outer diameter slightly larger than that of the developing sleeve 9A so that a gap corresponding to the developing gap can be formed between the developing sleeve 9A and the outer peripheral surface of the developing sleeve 9A.

Therefore, the developing sleeve 9A has a certain developing gap (0.3 to 1
mm), and the developing device 9 can always perform proper developing processing. Note that the same applies to the other developing devices 8 and 10.11, and the abutment rollers incorporated therein are pressed against the guide member 4 by a well-known biasing mechanism.

Furthermore, 70 shown in FIG. 9(C) is an image exposure means, which consists of an optical system that integrates a convergent light transmitting body 70A and a light emitting part 70B such as an LED, and the light emitting part 70B protrudes from both ends of the casing. A protrusion 70C having a predetermined height is integrally formed as this member.

The optical system 70 is equipped with a plate spring or the like, as in the case of the charger 6, so that each protrusion 70G is in pressure contact with the guide member 4 on the outside of the photoreceptor belt l. It is always positioned at a constant distance from the circumferential surface and can accurately form an image on the photoreceptor.

Furthermore, regarding the photoreceptor belt 1, it is shown in FIG. 6(A).

As shown in (B) and (C), a pair of continuous kite rails IA are integrally formed on the inner periphery and the guide rails IA are engaged with the guide grooves 4C of the guide member 4, so that the problem is likely to occur during transportation. This prevents the photoreceptor belt l from meandering.

The cleaning means is described above, which cleans the electrodes at least once every 1,000 copies, and which cleans the electrodes frequently in synchronization with proper loading of the paper feed cassette. Naturally, C, T (large cassette trays), tray paper feeding means, etc. are also mounted as paper feeding means.

Further, the electrode for cleaning is not limited to only a charging electrode, but also includes a corona electrode such as a transfer 9-separation electrode.

〔Effect of the invention〕

Normally, approximately 50 to 500 sheets of paper are inserted into a cassette, and the cassette is inserted and removed to replace paper every 400 to 500 copies on average. A color image forming device is provided in which charging wires can be cleaned automatically at appropriate times, and as a result, it is possible to always apply an even charge to the photoreceptor and obtain high-quality images. To be done and Natsu tko.

[Brief explanation of drawings]

1 and 7 are cross-sectional configuration diagrams of a color image forming apparatus of the present invention, and FIG. 2 is a block diagram showing an image forming system.
3 and 4 are a front view and a plan view of the main parts of the process cartridge, FIGS. 5 and 8 are configuration diagrams of the discharge electrode device, FIG. 6 is an explanatory diagram regarding the operation of the cleaning device, and FIG.
The figure is a sectional view of main parts of an image forming apparatus. ■...Photoreceptor belt 2, 3...Rotating roller 4
... Guide member 6.206 ... Charger 6
A, 206A...Discharge electrode device 6B, 206B
...Grid 7...Laser writing system unit 8.9.10.11...Developer 12...Transfer device 1
3...Cleaning device 14.214...Paper feed cassette/tooth 17...Timing roller 18...Fixing roller 30...Process cartridges 161A, 161B, 261A, 261B...Electrode block 162. 262...Charging wire 163.263...Main slide piece 164.264
...Sub piece 165.303...Drive wire 300...Drive member 301...Guide rail 302...Reel Gl, G2...Gears Fig. 2 (A) (B) (C) ( D)

Claims (1)

[Claims] A color image is formed by disposing a scorotron charger having at least a plurality of developing devices, a grid, and a charging wire around the periphery of a belt-like image forming body that moves while being stretched between two rotating rollers. A color image forming apparatus characterized in that a wire cleaning device provided in the scorotron charger is activated by an operation of attaching and detaching a paper feed cassette to and from a paper feed section.