JP2789042B2 - Color image forming equipment - Google Patents

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-shaped image forming body by an electrophotographic method and transferred to a transfer material to obtain an image. The present invention relates to a forming apparatus.

[Background of the Invention]

Many methods and apparatuses have been proposed for obtaining a color image using electrophotography. For example, as disclosed in JP-A-61-100770, a latent image is formed and developed on a photosensitive drum as an image forming body according to the number of separation colors of a document image,
There is a method in which a multicolor image is formed on a transfer drum by transferring the image on a transfer drum each time an image is transferred, and then transferred onto recording paper to obtain a color copy. In the apparatus according to this method, it is necessary to provide a transfer drum having a size capable of transferring one image on the peripheral surface in addition to the photosensitive drum, and the apparatus has a large and complicated structure. Inevitable.

Further, as disclosed in, for example, JP-A-61-149972, a latent image is formed and developed on a photosensitive drum in accordance with the number of separated colors of an original image, and is transferred onto a transfer material each time development is performed. This is a method of obtaining a multi-color copy. In this method, it is difficult to accurately superimpose multi-color images, and a high-quality color copy cannot be obtained.

In addition, there is a method in which a latent image is formed on the photosensitive drum in accordance with the number of separated colors of the original image and development with color toner is repeated, and a color image is obtained by superimposing and transferring a color toner image on the photosensitive drum. The basic process of this multicolor image formation is described in Japanese Patent Application Laid-Open Nos. 60-75850 and 60-76766 by the present applicant,
Nos. 60-95456, 60-95458, 60-158475 and the like.

In a multi-color image forming apparatus that obtains a color image by such superposition, a plurality of developing devices that store color toners of different colors are arranged on the periphery of the photosensitive drum. Rotates the photoconductor drum several times,
The color image is obtained by developing the latent image on the photosensitive drum.

As for the image forming body, a belt-shaped image forming apparatus in which a photoconductor is applied or mounted on a flexible belt together with a photosensitive drum having a photoconductor applied or deposited on the drum peripheral surface as described above. The body has also been proposed. The shape of the belt-shaped image forming body (hereinafter also referred to as a photoreceptor belt) is determined by being stretched between rotating rollers including a driving roller.
This is effective when a compact color image forming apparatus is configured by effectively utilizing the space. Further, since the photoreceptor belt can be executed along a small curvature, the transfer material can be separated by using a small-diameter rotating roller and utilizing the curvature portion, thereby preventing the transfer material from being separated poorly. .

[Object of the invention]

Such a belt-shaped image forming body is generally used by being stretched over a pair of rotating rollers provided in a horizontal direction in order to effectively use the volume of the apparatus main body, whereby the apparatus main body is formed in a drum shape. Although the vertical direction is reduced as compared with the apparatus having the photoreceptor described above, the horizontal direction is unavoidably increased considerably, so that there is a disadvantage in that the floor area is increased when installing.

The present invention solves this problem, and as a result, by using a belt-shaped image forming body, it is possible to particularly improve the transfer material separating function and to minimize the floor area of the apparatus as much as possible to easily install a compact color in a narrow space. It is intended to provide an image forming apparatus.

[Configuration of the invention]

The object is to provide a plurality of rotating rollers, a belt-shaped image forming member that is stretched and rotated between the rotating rollers, and a back side of the belt-shaped image forming member and the belt-shaped image forming member. And a support having a curvature formed to support the belt-shaped image forming body, and a plurality of developing units are arranged substantially horizontally to face the support, and the developing units maintain a gap. This is achieved by a color image forming apparatus having means for forming a gap between a developing device and a belt-shaped image forming body by directly contacting and facing the gap holding means with the support.

〔Example〕

One embodiment of the color image forming apparatus of the present invention is shown in FIGS.

In FIG. 1, reference numeral 1 denotes a flexible photoreceptor belt serving as a belt-shaped image forming member, and the photoreceptor belt 1 is suspended between rotating rollers 2, 3 and 21 disposed in a vertical direction. The sheet is conveyed clockwise by the driving of the moving roller 2.

Reference numeral 4 denotes a support member for supporting the photoreceptor belt, that is, a guide member that is in contact with the photoreceptor belt 1. The photoreceptor belt 1 is tensioned by the action of a tension roller 5 so that the inner peripheral surface thereof is formed. The guide member 4 is rubbed.

Accordingly, the photosensitive member on the outer peripheral surface of the photosensitive belt 1 is always kept at a fixed relation to the surface of the guide member 4 even during the conveyance, so that a stable image forming surface can be formed.

6 is a scorotron charger as charging means, 7 is a laser writing system unit as image exposing means, and 8 to 11 are developing devices as a plurality of developing means each containing a developer of a specific color. Is disposed on the photosensitive belt 1 at a position in contact with the rotating roller 2 or the guide member 4.

As the laser writing system unit 7, in addition to the optical system shown in the figure, an optical system or the like in which a light emitting unit and a converging light transmitter are integrated is used.

Each of the developing units 8, 9, 10, and 11 contains, for example, each of yellow, magenta, cyan, and black developers, and each developing sleeve that maintains a predetermined gap from the photosensitive belt 1.
8A, 9A, 10A, and 11A, and has a function of visualizing development on the photoreceptor belt 1 by a non-contact development method. Unlike the contact development, the non-contact development has an advantage of not hindering the movement of the photosensitive belt.

Reference numeral 12 denotes a transfer unit, 12A denotes a static elimination bar, 13 denotes a cleaning device, and a blade 13A and a toner conveying roller 13B of the cleaning device 13 are kept at a position separated from the surface of the photoreceptor belt 1 during image formation. It is pressed against the surface of the photoreceptor belt 1 only during cleaning, 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. That is, the data obtained by the color image data input unit (FIG. 2A) in which the image sensor scans the original image is converted into an image data processing unit (2
The image data is created by performing arithmetic processing in FIG. 2B, and is temporarily stored in the image memory (FIG. 2C). Next, the image memory is taken out at the time of recording and inputted to a recording section (FIG. 2 (d)), for example, 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 unit 7, the laser writing unit 7 generates a laser beam generated by a semiconductor laser (not shown). Is rotated by a polygon mirror 7B rotated by a drive motor 7A, the optical path is bent by mirrors 7D and 7E via an fθ lens 7C, and the photoreceptor belt 1 is charged in advance by a charger 6 as a charging means. Is projected on the peripheral surface of the substrate 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 is transmitted to the photosensitive belt 1.
Is scanned on the peripheral surface of. Therefore, a latent image corresponding to the first color is formed on the peripheral surface of the photosensitive belt 1 by the main scanning by the laser beam and the sub-scanning by the conveyance of the photosensitive belt 1. This latent image is developed by a developing unit 8 loaded with yellow (Y) toner (a visual medium) in the developing means.
A toner image is formed on the belt surface. The obtained toner image passes under the cleaning device 13 as cleaning means 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 unit is input to the writing system unit 7. Similarly, writing is performed on the drum surface to form a latent image. The latent image is developed by the developing device 9 loaded with magenta (M) toner as the second color.

The 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) toner, and forms a cyan (C) toner image on the belt surface based on a control signal generated by a signal processing unit.

Further, reference numeral 11 denotes a developing device having a black toner, which forms a black toner image on the drum surface by the same processing. A DC or further AC bias is applied to each sleeve of each of these developing devices 8, 9, 10 and 11, and a jumping development is performed by a one-component developer or a two-component developer as a visualization means, and the base is formed. Development is performed on the grounded photosensitive belt 1 in a non-contact manner.

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

That is, one of the uppermost layers of the transfer material accommodated in the paper feed cassette 14 is carried out by the rotation of the paper feed roller 16, and the transfer material is transferred to the transfer device 12 via the timing roller 17 in synchronization with the image formation on the photosensitive belt 1. Supplied to.

The transfer material to which the image has been transferred is surely separated from the photoreceptor belt 1 which suddenly changes its direction along the rotating roller 2 and heads to the left, where the image is fused by the fixing roller 18 and then discharged. The sheet is discharged to the tray 20 via the rollers 19.

On the other hand, the photoreceptor belt 1 which has finished transferring to the transfer material turns upward and continues to be conveyed, and the toner remaining in the cleaning device 13 in which the blade 13A and the toner conveying roller 13B are pressed against the rotating roller 21 is pressed. After the removal, the blade 13A is separated again after the completion, and the toner transport roller 13B is separated a little later, and a new image forming process is started.

The photoreceptor belt 1, the guide member 4 and the charger 6,
The cleaning device 13 is, as shown in FIG.
Seven units are housed between 30A and 30B, and are attached to and detached from the apparatus main body as independent cartridges 30.

That is, the substrates 30A and 30B are integrated via the guide member 4 and the stay 31, and the photosensitive belt 1 is interposed therebetween.
The bearings support the rotating rollers 2, 3, and 21, and the tension roller 5, and further sandwich the charger 6 and the cleaning device 13.

The guide member 4 has a hollow toner collecting container therein.
4A, an end of a toner transport pipe 34 for transporting waste toner collected from the cleaning device 13 is connected to an upper portion of the toner recovery container 4A.

The cartridge 30 is inserted horizontally into the apparatus main body from the front and mounted. At the time of insertion, a handle 35 attached to the front surface is used.

Inside the main body of the apparatus, there are provided two drive and fixed shafts which are fitted to the respective shaft cores of the rotating rollers 2 and 3, and by externally fitting the rotating rollers 2 and 3, respectively. The cartridge 30 is supported and mounted on the apparatus main body.

FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3, in which the rotary rollers 2 and 3 are each formed of a ring-shaped rib R1 formed on the inside of each of the substrates 30A and 30B in the cartridge 30 alone. And R2 are supported in a loosely fitted state.

On the other hand, a drive shaft 2A having a gear G connected to the power system of the device and a fixed shaft 3A protrude from the main body of the device, and the rotating rollers 2 and 3 are respectively attached to the drive shaft 2A and the fixed shaft 3A. When the cartridge 30 is fitted, the position and the interval of the rotating rollers 2 and 3 are determined at the same time as the cartridge 30 is supported, so that the photosensitive surface of the photosensitive belt 1 is also set at a predetermined position.

The drive shaft 2A and the fixed shaft 3A are inserted through the respective rotation rollers 2 and 3, and then the nut 2B is tightened to drive the rotation roller 2 into the drive shaft.
The rotary roller 3 is fixed to and integrated with 2A, and the rotating roller 3 is rotatably held with respect to the fixed shaft 3A by attaching a nut 3B.

In addition, it is assumed that the cartridge 30 itself is held by locking either the substrate 30A or 30B to the apparatus main body after the cartridge 30 is mounted on the apparatus main body.

The cartridge 30 has a toner conveying pipe 34 having a built-in flexible toner conveying screw 33 on its front surface. One end is formed at the bottom of the cleaning device 13 and the other end is formed inside the guide member 4. Toner recovery container 4A
And a toner collection port 34A is opened.

The toner conveying screw 33 is driven and rotated by the power of the apparatus main body, and thereby sends the collected toner of the cleaning device 13 to the toner collecting container 4A via the toner conveying pipe 34 and stores the toner.

The collected waste toner is stored in the toner collection container 4A by its own weight.
The toner collecting container 4A can store a large amount of waste toner until it reaches its full capacity without causing local accumulation.

FIG. 5 shows a structure for setting the relative positions of the respective image forming means with respect to the photoreceptor belt 1, and FIG.
Fig. 5 (A) shows the main part with the XX cross section in the figure.
FIG. 5 (B) shows an essential part of the developing means with an arrow YY section, and FIG. 5 (C) shows an optical system having a converging light transmitting body with an ZZ section of an image exposing means. Show.

Backplate 6A in FIG. 5 (A) charger 6, 6B each electrode blocks attached to both ends of the back plate 6A, W ₁ is a wire electrode that is stretched between the electrode block 6B . W ₂ is the grid.

Each of the electrode blocks 6B is integrally formed with a projection 6C having a predetermined height as a contact member, and each projection 6C of the charger 6 is pressed against the rotating roller 3 outside the photoreceptor belt 1. It is urged by an elastic member 6D such as a leaf spring.

Thus the electrode wire W ₁ and grid W ₂ is always relative to the peripheral surface of the photosensitive belt 1 is located kept a certain distance, it is possible to reliably charge the photosensitive member to a predetermined potential.

In FIG. 5B, reference numeral 9A denotes a developing sleeve of the developing device 9, and 9B denotes an abutting roller serving as a spacing means.
B is rotatably supported by a rotating shaft 9C of the developing sleeve 9A.

The abutting roller 9B is formed from the developing sleeve 9A so that when pressed against the guide member 4, the peripheral surface of the developing sleeve 9A can form a gap corresponding to the developing gap between the peripheral surface of the photosensitive belt 1 and the developing sleeve 9A. It has a slightly larger outer diameter.

Accordingly, the developing sleeve 9A forms a constant developing interval (0.3 to 1 mm) suitable for non-contact development between the developing sleeve 9A and the outer peripheral surface of the photoreceptor belt 1, and the developing device 9 can normally perform an appropriate developing process. . The same applies to the other developing devices 8 and 10, and each of the built-in abutting rollers is pressed against the guide member 4 by an urging mechanism described later.

The structure and function of each developing device will be described using the developing device 9 as an example.

FIG. 6 shows a cross section of the developing device 9. 9A is a developing sleeve containing a magnet roller and a coaxial abutting roller.
9B, the photosensitive drum 1 is driven and rotated counterclockwise while maintaining a predetermined developing interval between the photosensitive belt 1 and the peripheral surface thereof. Reference numeral 19A is a rigid and magnetic thin layer forming member which is pressed against the developing sleeve 9A with a predetermined load in a state where no developer is interposed. 19
B and 19C have a screw structure, and are a pair of toner transport screws for transporting and circulating the developer in opposite directions to each other. The toner transport screw has a function of sufficiently stirring and mixing the toner and the carrier and sending the developer to the developing sleeve 9A. .

The toner transport screw 19B and the toner transport screw 19C are members that also serve as a stirring member that rotates in directions opposite to each other. Then, the drawing is conveyed to the near side by the thrust, and the homogeneous developer triboelectrically charged by the mixing action of the toner and the carrier between them is formed into a layer on the peripheral surface of the developing sleeve 9A via the supply roller 19E. Adhere to.

This developer layer adhered on the peripheral surface of the developing sleeve 9A to form a thin layer is used to transfer a latent image on the peripheral surface of the photoreceptor belt 1 conveyed in the time direction in the development area at a distance of the development interval described above. Develop by contact to form a toner image.

During this non-contact development, a developing bias including an AC component is applied to the developing sleeve 9A from a power source (not shown), and as a result, only the toner in the developer is selectively transferred to the surface of the latent image on the developing sleeve 9A. Is attached.

The developer having consumed the toner component has a high carrier ratio and is conveyed by the developing sleeve 9A to be scraped by the scraper 19D.
And the developer with a high toner ratio is mixed again.

On the other hand, reference numeral 17 shown in FIG. 5 (C) denotes an image exposure means, which comprises an optical system in which a convergent light transmitting body 17A and a light emitting portion 17B corresponding to an LED are integrated, and the light emitting portion 17B protrudes from both ends of the casing. As the member, a projection 17C having a predetermined height is integrally formed.

The optical system 17 is urged by an elastic member such as a leaf spring so that each of the projections 17C is pressed against the rotating roller 3 outside the photoreceptor belt 1 as in the case of the charger 6.

Therefore, the optical system 17 is also always located at a constant distance from the peripheral surface of the photoreceptor belt 1 so that an image can be accurately formed on the photoreceptor.

4 and 5, a pair of continuous guide rails 1A are integrally formed on the inner periphery of the photoreceptor belt 1, and the guide rails 1A are engaged with the guide grooves 4B of the guide member 4. Further, by engaging with the same guide grooves 3B and 2B of the rotating roller 3 or the driving roller 2, meandering of the photosensitive belt 1 which is likely to occur during conveyance is prevented.

As shown in the example of the developing device 9 shown in FIG. 6, each of the developing devices has a pair of front and rear moving rollers 29B on the bottom surface of the housing 29A.
And a support table 40 of the developing garage 40 shown in FIG.
It is built so that it can move horizontally on A.

The right side of the developing unit 9 is a toner box 39A.
The supply toner stored in the toner box 39A is supplied to the inside of the developing device by the rotation of the toner supply roller 39B and the sponge roller 39C.

Further, the developing device 9 engages a regulating pin 29D on a projection 29C on the right outside surface of the housing 29A with a groove cam 43 of a cam plate 42 integrated with a rotating shaft 41 provided on the developing garage 40.

When the rotation shaft 41 is in the clockwise rotation position, the groove cam 43 of the cam plate 42 is
Is moved to the left, that is, to the photoreceptor belt 1 side, and the regulating pin 29D is in a free state. As a result, the developing unit 9 is extended with the tension spring 44 extended between the developing unit 9 and the developing garage 40.
The urging roller 9B is urged in the left direction, that is, in the direction of the photoreceptor belt 1 by the action of, so that the abutting roller 9B is brought into contact with the guide member 4 to set the position of the developing sleeve 9A with respect to the photoreceptor belt 1 as described above.

On the other hand, when the rotation shaft 41 is rotated half a counterclockwise direction, the groove cam 43 moves to the right, that is, the direction to retract the developing device 9 away from the photoreceptor belt 1 via the regulating pin 29D, thereby. The cartridge 30 can be attached to and detached from the apparatus main body.

By moving each developing unit individually to the right, the shielding plate 39D can be opened as in the example of the developing unit 9 shown in FIG. 7, so that toner can be supplied to the toner box 39A. Become.

[Effects of the Invention] The present invention provides an image forming surface that constitutes a flexible belt-shaped image forming body in the vertical direction of the apparatus main body,
A color image forming apparatus that is compact and easy to maintain and has excellent practicality as a result of reducing the floor area occupied when installing the apparatus and enabling easy and reliable collection of waste toner inside the image forming body. Will be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of the color image forming apparatus of the present invention, FIG. 2 is a block diagram showing an image forming system, and FIGS.
5 and 5 are a front view, a sectional view, and a sectional view of a main part of the cartridge of the apparatus. FIG. 6 is a sectional view of the developing device.
The figure is a front view of the developing garage. DESCRIPTION OF SYMBOLS 1 ... Photoreceptor belt, 2, 3, 21 ... Rotating roller 4 ... Guide member, 4A ... Toner collection container 2B, 3B, 4B ... Guide groove, 5 ... Tension roller 6 ... Charger 7 … Laser writing system units 8, 9, 10, 11… Developing unit 12… Transfer unit 13… Cleaning device 14… Paper cassette 16… Discharge roller 17… Timing roller 18… Fixing roller, 19: Discharge roller 20: Tray, 30: Cartridge 30A, 30B: Substrate, 31: Stay 33: Toner transport screw 34: Toner transport tube, 35: Handle 40: Development Garage, 40A ... Support 42 ... Cam plate, 43 ... Groove cam

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-133473 (JP, A) JP-A-63-16763 (JP, A) JP-A-63-287975 (JP, A) JP-A-57- 34576 (JP, A) JP-A-60-70470 (JP, A) JP-A-63-125973 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 13/01 G03G 15 / 01-15/01 117 G03G 21/00 340-360

Claims (1)

(57) [Claims] A plurality of rotating rollers; a belt-shaped image forming member which is stretched between the rotating rollers and rotates; and a belt-shaped image forming member which is on the back side of the belt-shaped image forming member. A support having a curvature formed to be wider than the width of the body and supporting the belt-shaped image forming body; and a plurality of developing devices arranged substantially horizontally facing each other with respect to the support. A color image forming apparatus having a holding means, wherein a gap between the developing device and the belt-shaped image forming body is formed by directly contacting and facing the gap holding means with the support.