JPH0396976A - Color image forming device - Google Patents

Abstract

PURPOSE:To obtain invariably high picture quality by providing a scorotron charger with a wire cleaning device, uniting a grid with a beltlike image forming body and attaching it to an image forming device main body detachably. CONSTITUTION:The scorotron charger 6 consists of a discharging electrode device 6A wherein the charged wire 162 is stored and the grid 6B provided at its front. Then the device 6A is fitted on the device main body side while the grid 6B is divided into the side of a process cartridge 30. The grid 6B is fitted directly to a guide member 4 through a protection cover 60 and a grid fitting member 61, so it is positioned with high accuracy about the photosensitive surface of the photosensitive body belt. The device 6A has projections T formed on electrode blocks 161A and 161B and the projections T are pressed against the guide member 4 by a leaf spring 166 outside the grid 6B. Therefore, the charged wire 162 is also positioned with high accuracy about the photosensitive surface of the photosensitive body belt, and consequently the photosensitive body can securely be charged electrostatically to a specific potential.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a color image forming apparatus in which a toner image is formed on a belt-shaped image forming body by electrophotography and transferred onto a transfer material to obtain an image. The present invention relates to an image forming apparatus, and particularly to a color image forming apparatus configured to apply an electric charge to the bell-shaped image forming member by a scorotron charger.

[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 above publication, a latent image is formed and developed on a photoreceptor drum, which is an image form, according to the number of separated colors of the original image, and each time the development is performed, the latent image is transferred onto a transfer drum. 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. 149972/1983, a latent image is developed on a photosensitive 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 method is used to obtain 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 2 according to the number of separated colors of the original image and develop it with color toner, and then transfer the color images after superimposing them on the photoreceptor drum to obtain a color image. There is. The basic process of forming a multicolor image is disclosed in Japanese Patent Application Laid-open No. 60-75850 and No. 60 No. 75850 by the present applicant.
-76766, 60-95456, 60-95
No. 458, No. 60-158475, and the like.

In a multicolor image forming apparatus that obtains a color image through such superposition, a plurality of developing units containing color 1 and toner of different colors are arranged around the periphery of the photoreceptor drum. , generally the photoreceptor drum is rotated multiple times,
A color image is obtained by developing the latent image on the photosensitive drum.

Regarding the image-forming body, as explained above, in addition to the photoconductor drum with a photoconductor coated or vapor-deposited on the circumference of the drum, a belt-shaped image formation with the photoconductor coated or attached on a flexible belt is considered. The body is also suggested. Since the shape of the bell 1-shaped image forming body (hereinafter referred to as photoconductor bell) is determined by being stretched between rotating rollers including a drive roller, the color is made into a compact shape by effectively utilizing the space. This is effective when configuring an image forming apparatus.

[Purpose of the invention]

For such an image forming body, such as a photoreceptor such as PC, a scorotron charger is used, in which a grid is arranged near the surface of the photoreceptor in order to apply a uniform potential regardless of the presence or absence of toner on the photoreceptor layer or previous charging. .

However, in the above-mentioned image forming device that forms a color image by superimposing a color image, there is charge from the top of the toner image, so the grinder and the wire of the charger are easily contaminated, which can lead to uneven discharge and uneven discharge. Application of potential becomes impossible. Particularly when the charger is installed below the photoreceptor, the dirt is particularly noticeable.

Regarding the wire of the charger, are chargers with a built-in wire cleaning device already available so that dirt can be cleaned while attached to the device body? 4. Furthermore, there was a problem in that it was difficult to clean it easily, partly because it was disposed close to the surface of the photoreceptor.

As a result of solving and improving this problem, the present invention provides a color image forming apparatus that can stably obtain high-quality images by making cleaning and maintenance of the entire charger including the grid extremely easy. This is the purpose.

[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. In the color image forming apparatus for forming a color image forming apparatus, a wire cleaning device is provided, and the grid is integrated with the belt-shaped image forming body and is detachable from the image forming apparatus main body. This is achieved by a color image forming apparatus having the following characteristics.

〔Example〕

An embodiment of the color image forming apparatus of the present invention is shown in FIGS. 1 to 7.

In FIG. 1, ■ is a flexible photoreceptor bell 1 which is a bell-shaped image forming body, and the photoreceptor bell 1 is a rotating roller 2.
and 3, and is conveyed clockwise by the drive of a rotating roller 2 consisting of a rubber roller.

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 peripheral surface of the photoreceptor belt 1 are always maintained at a fixed relative position with respect to the surface of the guide member 4 even during conveyance, making it possible to maintain 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 opposite to the outer peripheral surface of the photoreceptor bell I.1 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.

Each of the developing units 8 , 9 . 10 and II contain developer sleeves of yellow magenta, cyan, and black, respectively, and are provided with developing sleeves 8A, 9A, IOA, and IIA that maintain predetermined gaps with the photoreceptor bells 1 and 1, and It has the function of making the latent image on the bell 1.1 visible 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.

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 used to form an image or a photoconductor bell!・1
The photoreceptor bell 1-1 is kept in a position apart from the surface of the photoreceptor bell 1-1, and is pressed against the surface of the photoreceptor bell l-1 as shown in the figure only during cleaning after image transfer.

A color image forming process by the color image forming apparatus is performed as follows.

First, the multicolor image formation according to this embodiment or the image formation system shown in FIG. 2 is performed. In other words, the color image data input section (Figure 2 (a)) where the image sensor scans the original image.
) is subjected to arithmetic processing in an image data processing section (Fig. 2 (portion)) to create image data, which is temporarily stored in an 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 (2)).
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 passed through a tθ 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 1, which has been charged in advance by a charger 6, which is a charging means, to form a bright line.

7 8 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, a latent image corresponding to the first color is formed on the circumferential surface of the photoreceptor belt 1 by main scanning by the laser beam and sub-scanning by the conveyance of the photoreceptor belt 1. This latent image is produced by yellow (Y) 1.
A toner image is formed on the surface of the bell 1 by a developing device 8 loaded with a toner image medium (8 image media). The obtained toner image passes under a cleaning device 13, which is a cleaning means, which is separated from the peripheral surface of the photoreceptor belt 1 while being held on the belt surface, 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 unit 7, and the second color signal is inputted to the writing system unit 7, and the second color signal is inputted to the writing system unit 7. In the same manner, writing is performed on the drum surface to form a latent image. The latent image is developed by a developing device 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.

Reference numeral 10 denotes a developing device having cyan (C) 1.toner, which forms a cyan (C) toner image on the belt surface based on a control signal generated by a signal processing section.

Furthermore, II is a developing device having black toner, and a black toner image is superimposed and formed on the drum surface by the same process. These developing units 8, 9, 10 and 1l
A direct current or even alternating current bias is applied to each sleeve, and jumping development is performed using a two-part developer, which is a developing means, and non-contact development is performed on the photoreceptor belt 1 whose base is grounded. It looks like this. Incidentally, in the development step 1, non-contact development using a certain amount of developer can also be used.

The color toner image thus formed on the circumferential surface of the photoreceptor belt 1 is sent from the paper feed cassette l4 via the paper feed guide 15 at the transfer section and is transferred onto a transfer material.

That is, the transfer material accommodated in the paper feed force sets 1 and 14 is conveyed out by the rotation of the paper feed roller 16, and is conveyed via the timing roller 17 to the photoreceptor bells 1 and 1. are combined and supplied to the transfer device 12.

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 1, which suddenly changes direction along the direction, and moves upward, and after welding the image to the fixing roller 18, it is ejected onto the tray 20 via the ejection roller 19.

On the other hand, the photoconductor bell 1, which has completed the transfer to the transfer shrine, continues to be conveyed to the blade 13A and the toner conveying roller 13B.
The remaining 1.toner was removed in the cleaning device 13, which was brought into pressure contact with the blade +3A, and after that, the blade +3A was separated again using a ball, and a little later, the toner supply roller 13B was deposited on the tip of the blade 13A!
- After smoothing out the toner, 1. Separate the na supply roller 13B and start a new image forming process.

The photoconductor bell }I is the same as the cleaning device 13.
As an independent unit incorporated into a process cartridge 30 as shown in FIG. 3, it is attached to and detached from the main body of the apparatus.

That is, the process force-1 ridge 30 is applied to the rotary rollers 2 and 3 with the photoreceptor belt 1 stretched between the front and rear substrates 30A and 30B, which are integrated by two stays 31 and the guide member 4. The rotary roller 3
A cleaning device 13 is sandwiched and supported at a position opposite to the circumferential surface of the cleaning device 13.

The guide member 4 has a part of its volume as a toner collection container 4A, and the toner removed from the circumferential surface of the photoreceptor belt l in the cleaning device l3 is transferred to the toner transport pipe 4.
It is designed to be transported and recovered via B.

The process cartridge lithography 30 has each substrate 30A and 30B.
A pair of engagement 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.

The scorotron charger 6 is composed of a discharge electrode device 6A containing 12 charging wires and a grid 6B disposed in front of the discharge electrode device 6A. 6A to the apparatus main body side, and the grid 6B to the process force -1.
- Install it separately on the ridge 30 side (1).

FIG. 4 is an exploded view of the principal part of the process carriage 30 in the plane shown in the direction of arrow D in FIG.

Reference numeral 60 in FIG. 4 is a protective cover that covers the photosensitive surface of the photosensitive belt l that is attached to the guide member 4, and is fixed by adhesive or the like to the raised portion 4C of the guide member 4 while being slightly spaced 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 forms or means described above, and the image forming process by each image form or means is performed with the protective cover 60 attached. It looks like this.

Reference numeral 6l denotes a grid mounting member fixed to both ends of the square hole 60A by adhesive or the like, and a grid wire is wound around the protrusion on the grid mounting member 61 to form the grid 6B.
will be considered.

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 are electrode blocks 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.
This is a sub-piece rotatably supported on 3A.

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 block 161A.
60A.

The gear device includes a worm W connected to the power shaft, and a stage gear Gl that integrates a worm gear that meshes with the worm W.
and the 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 bronck 161B on the opposite side around a coaxially integrated cylinder S a plurality of times to create a tensioned state, and one of the drive wires 165 that is sheared in parallel. is held between the pins 164A on the sub-piece 164.

When the main slide piece 163 is not being cleaned, it is located on the electrode block 161B side as shown by the broken line and is retracted outside the maximum effective screen width L on the photosensitive surface. Due to the force, the →knob piece 164 is slightly rotated counterclockwise, and as a result, each of the square columns 164B is released from pressure contact with the charging wire 162 and is maintained at a spaced angle.

During cleaning, the gear device is activated by the rotation of the power shaft to rotate the gear G2 or the cylinder S counterclockwise.

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
2. Removal and cleaning of l-ner and foreign matter adhering to 2 is performed.

Thus, the color image forming device of the present invention has a scoro 1
- The Ron charger 6 can be cleaned with the grid 6B removed from the device main body, while the charging wire 6B can be cleaned with the charging wire 6B still attached to the device main body.

FIG. 6 shows the setting of the relative position of each image forming means related to the present invention with respect to the photoreceptor belt 1. As for the charging means, its main part is shown in FIG. Regarding the developing means, the main part is shown in FIG. 6(B) with a cross section indicated by the arrow BB, and as for the image exposure means, an optical system having a convergent light transmitting body in place of the laser optical system is shown in a similar cross section. Figure 6 (C
).

In FIG. 6(A), the grid 6B is directly attached to the guide member 4 via the aforementioned protective cover 60 and the grid attachment part 61, so that a highly accurate position can be maintained with respect to the photosensitive surface of the photosensitive belt l. .

On the other hand, regarding the discharge electrode device 6A, the electrode bronck 161A
and 161B are each formed with a protrusion T, and the guide member 4 is provided with the protrusion T on the outside of the grid 6B.
It is urged by an elastic member 166, such as a plate bar, so as to come into pressure contact with the plate.

Therefore, the charging wire 162 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. 6(B), 9A is a developing sleeve of the developer a1], and 9B is an abutting member, which is an abutting roller, and the abutting roller 9B is rotatably supported by a bearing on the rotating shaft 9C of the developing sleeve 9A. has been done.

The abutment roller 9B is slightly larger than the developing sleeve 9A so that when pressed against the guide member 4, a gap corresponding to the developing gap can be formed between the circumferential surface of the developing sleeve 9A and the outer circumferential surface of the photoreceptor belt l. It has a large outer diameter.

Therefore, the developing sleeve 9A has a certain developing gap (0.3 to 1
mm), the developing device 9 can always perform proper developing processing. The same applies to the other developing devices 8, 10, and 1.1, and the abutment rollers built in therein are pressed against the guide member 4 by a well-known biasing mechanism.

Furthermore, the reference numeral 70 shown in FIG. 6(C) is an image exposure means, which is composed of an optical system including a convergent light transmitting body 70A and a light emitting section 70B such as an LED, and the light emitting section 70B protrudes from both ends of the casing. A protrusion 70C having a predetermined height is integrally formed as this member.

In the optical system 70, each of the protrusions 70C is a photoreceptor bell}・l
An elastic member 70D, such as a plate spring, is attached to the outside of the charger 6 so as to be in pressure contact with the guide member 4.
"Ni": is being encouraged.

Therefore, the optical system 70 is also positioned at a constant distance from the circumferential surface of the photoreceptor bell l-1, so that an image can be accurately formed on the photoreceptor.

Furthermore, regarding the photoreceptor belt 1, (A) and (B) in FIG.
). As shown in (C), a pair of continuous guide rails LA are integrally formed on the inner periphery of the guide 1J, and the guide rail 1J is engaged with the guide groove 4C of the guide portion 4A, so that the guide rail 1J is engaged with the guide groove 4C of the guide portion 4A. This prevents the photoreceptor bells 1, 1 from meandering, which is likely to occur.

In this embodiment, a device that forms a color image by four rotations of the photoreceptor belt 1 has been described, but the present invention provides an image forming apparatus that forms seven color images by one rotation of the photoreceptor belt 501 as shown in FIG. It can also be applied to formal devices.

Such an image forming apparatus includes a plurality of developing devices 130, 230, 330, . 130, a plurality of chargers 110, 210, 310, 4]'0 and a plurality of image exposure devices 120, 220, 320, 420 are arranged in parallel to form latent images corresponding to respective colors. , photoreceptor belt 50], there are a plurality of grids II corresponding to the chargers described above.
OB, 210B, 310B, and 410B are provided, respectively.

Therefore, as in the previous example, cleaning of the green nozzle is performed by taking out the process cartridge 1 and the litho from the apparatus main body, and the charging wire can be cleaned with the cleaning device built into each charger while it is attached to the apparatus main body. be exposed.

Regarding the cleaning device 513, the blade 513
A and 1/Gner supply roller 5] 3B is always the photoreceptor belt 5
A device of the type that is in pressure contact with the 01 surface is used.

〔Effect of the invention〕

As a result of the present invention, maintenance of the Scoro 1/Ron charger, especially grid cleaning and inspection, can be performed extremely easily and safely, and as a result, high quality images can always be obtained even with easy handling. A color image form or device was provided.

[Brief explanation of drawings]

1 and 7 are cross-sectional views of the color image forming apparatus of the present invention, FIG. 2 is a bronch diagram showing the image forming system, and FIGS. 3 and 4 are front views of the P1:I access cartridge nozzle. FIG. 5 is a structural diagram of a discharge electrode device, and FIG. 6 is a sectional view of a principal part of the image forming apparatus. l...Photoreceptor belt 2, 3-...Rotating roller 4...
- Guide member 6... Charger 6A... Discharge electrode device 6B... Grid 7... Laser writing system units 8, 9, 10.11... Developer l2... Transfer device 13... Cleaning device 14...Paper feeding power center l7...Timing roller l8...Fixing roller 3
0...Process cartridge 60...Protective cover 60A, 60B, 60C...
Square hole 6L...Grid mounting part Hayashi

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. 1. A color image forming apparatus, wherein the scorotron charger is provided with a wire cleaning device, and the grid is integrally attached to the belt-like image forming body and is removable from the main body of the image forming apparatus.