JPH0378771A - Color image forming device - Google Patents

Abstract

PURPOSE:To make each image forming means freely attachable/detachable without interfering with each other by providing a means moving a belt-like image forming body in an upstream direction in which the body is separated from plural developing units and a means parallel-moving the body in a direction perpendicular to the above-mentioned direction. CONSTITUTION:Image forming means such as a photosensitive belt 1, a guide member 4, an electrifying part 6 and a cleaning device 13 are incorporated into a process cartridge composed of front and back substrates 30A and 30B inserted into a device main body as a unit. In a cartridge 30, the substrates 30A and 30B are formed integrally via the guiding member 4 and two stays 31, and the cartridge is inserted into the device main body in a horizontal posture from the front of the device and housed therein. To load the cartridge 30, a back engaging pin P2 is inserted into the oblong hole 111 of a back side plate 110B, and a slope 112A is pushed to slide a pressure plate 112 upward. After engagement, the cartridge is brought into press-contact with the lower edge of the oblong hole 111 by the pressure of the pressing plate 112. Thus, each image forming means can be freely attached/detached without interfering with each other.

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, Japanese Patent Publication No. 61100770
As disclosed in the publication, a latent image is formed and developed on a photosensitive drum, which is an image carrier, according to the number of separated colors of the original image, 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 photoconductor drum according to the number of separated colors of the original image and develop it with color 1 to toner, and then transfer the color toner images after superimposing them on the photoconductor drum to obtain a color image. be. The basic process of forming a multicolor image is disclosed in Japanese Patent Application Laid-open No. 60-75850 and No. 60-75850 by the present applicant.
No. 76766, No. 60-95456, No. 60-954
No. 58, No. 60-158475, 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 that include all drive rollers, so this color image forming device is compact in size and makes effective use of space. It is effective when configuring . In addition, since the photoreceptor bell i can travel along a small curvature, a rotating roller with a small diameter is used to separate the transfer material by utilizing this curvature to prevent defects in the separation of the transfer material. You can also do that.

[Purpose of the invention]

In the color image forming apparatus using the above-mentioned photoreceptor belt, each image forming means such as a charging means, an image exposure means, a plurality of developing device groups, and a cleaning means are located mainly below the outer peripheral surface of the photoreceptor belt. Although these image forming means are installed facing the peripheral surface, each of these image forming means, including the photoreceptor belt, is housed as a unitized process cartridge in an independent form and can be freely attached to and detached from the main body of the apparatus.

However, when such many image forming means are integrated, the cartridge becomes large and heavy, and not only is it difficult to attach and remove it from the main body of the apparatus, but also each image forming means may have different service life and maintenance frequency. This is considered to be inconvenient from a maintenance and management perspective; 3 points are common.

As a result of solving this problem and improving the present invention, the present invention forms a color image that allows each image forming means, including the photoreceptor belt, to be attached to and detached from the main body of the apparatus without interfering with each other by extremely easy operation in response to maintenance inspection. The purpose is to provide equipment.

[Structure of the invention]

The above object is to provide a color image forming apparatus in which a plurality of developing units are disposed facing each other on the lower periphery of a moving belt-like image forming body stretched between two rotating rollers disposed in the horizontal direction. This is achieved by a color image forming apparatus characterized in that it has means for moving the belt-shaped image forming body upward away from the plurality of developing devices and means for moving it in parallel in a direction perpendicular thereto.

〔Example〕

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

In FIG. 1, reference numeral 1 denotes a flexible photoreceptor belt which is a belt-like image forming member. transported to.

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 inner peripheral surface of the photoreceptor belt (1) is brought into tension by the action of the tension roller (5). 4. Rub it. Note that the guide member 4 is provided with a recessed portion in an area unnecessary for image formation to reduce resistance due to rubbing. Of course, this recess does not need to be provided if the sliding resistance is low. In addition, in order to reduce the sliding resistance between the photoreceptor belt l or the guide member 4, a low friction member such as Teflon coating is provided on the surface of either the photoreceptor belt l-1 or the guide member 4, or the low friction member described above is provided. Preferably, it is made up of members.

Therefore, the photoreceptor on the outer peripheral surface of the photoreceptor belt is always maintained at a fixed position relative to the surface of the guide member 4 during conveyance, making it possible to form a stable image forming surface.

Further, by providing the developing device and the cleaning device below the photoreceptor belt, it is possible to prevent the developer from scattering or spilling.

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 retaining means.

In addition to the optical system shown in the drawings, an optical system that integrates a light emitting part and a convergent light transmitting body may be used as the laser writing system UNINO 1-7.

The developing devices 8.9.10.11 contain, for example, yellow magenta, cyan, and black developers, respectively, and the developing sleeves 8A, 9A, IOA, and IIA maintain a predetermined gap from the photoreceptor belt 1. , photoreceptor bell l-1
It has the function of making the upper latent image 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 plate, 13 is a cleaning device, and a blade 13A and a toner conveying roller 13B of the cleaning device 13 are connected to the photoconductor bell 1-1 during image formation.
The photoreceptor belt 1 is kept in a position apart from the surface of the photoreceptor belt 1, and is pressed against the surface of the photoreceptor belt 1 as shown in the figure only during cleaning after image transfer.

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 as shown in FIG.
It is carried out according to the stem. 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 color signal is generated by a semiconductor laser (not shown) in the laser writing system unit 1-7. The laser beam is rotated and scanned by a polygon mirror 7B rotated by a drive motor 7A, passes through an fθ rereno 7C, and then is sent to mirrors 7D and 7.
The optical path is bent by E, and a charger 6, which is a pre-charging means,
The light is projected onto the circumferential surface of the photoreceptor belt l to which electric charges are applied, forming 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 1 by the main scanning by the laser beam and the sub-scanning by the conveyance of the photoreceptor belt. 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 1-toner image is formed on the belt surface.

The obtained toner image, while being held on the surface of the belt 1, 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 photosensitive belt l is charged again by the charger 6, and then the second
The color signal is input to the writing system unit 7, and writing is performed on the drum surface to form a latent image in the same manner as in the case of the first color signal described above. The latent image is reversely developed in a non-contact manner 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.

A developing device 10 has cyan (C) toner, and forms a cyan (C) toner image on the drum 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 by the same process. A direct current or even an alternating current bias is applied to each sleeve of these developing devices 8, 9° IO, and 11, and jumping development is performed using an l-component or two-component developer as a developing means, and the substrate is grounded. Developing is performed on the photoreceptor belt 1 in a non-contact manner.

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 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 transported, and the cleaning device 13, in which the blade 13A facing the rotating roller 3 and the rotating toner transport roller 13B are brought into pressure contact, removes the remaining toner. After the removal is completed, the blade 13A is separated again by the ball, and a little later, the toner conveying roller 13B is separated from the blade 13A to begin a new image forming process.

The image forming means of the photoreceptor belt 1, the guide member 4, the scorotron charger 6, and the cleaning device 13 are comprised of a process cartridge composed of front and rear substrates 30A and 30B, as shown in FIG. 30 and is attached to and detached from the main body of the apparatus as a unit.

The cartridge 30 integrates the front and rear substrates 30A and 30B via the guide unit 4 and two stays 31, holds each of the image forming means between them, and holds the image forming means in a substantially horizontal direction from the front of the main body of the apparatus. It is inserted and stored in the correct position.

On the other hand, each of the developing units is incorporated in an integral and flexible developing container 41 as shown in FIG. It is attached and detached.

The developing container 41 has a plurality of compression springs 43 disposed in the front and back direction sandwiched between the bottom surface corresponding to the developing devices 8 and 11 and the supporting base 42, so that the circumferential surfaces of the developing sleeves are in contact with each other. The curvature of the curved surface formed by the guide member 4
The photoreceptor belt 1 is inserted horizontally from the front of the main body of the apparatus and stored in a state in which it is locked by the claw portion 42A so that the curvature is smaller than the curvature of the image forming surface of the photoreceptor belt l formed by the above.

The cartridge 30 and the developing unit 40 are
The front cover 100 of the device main body shown in the figure is attached to its support shaft 10.
It is inserted into the inside of the device main body by opening it toward the front side at a substantially right angle with 0A as a fulcrum.

6 and 7 are AA sectional views of the cartridge 30 shown in FIG. 3 and the developing unit 4 shown in FIG. 4, respectively.
0 shows a BB cross-sectional view.

The cartridge 30 is provided with a pair of engagement pins P1 and P2 at opposing positions on the outer surfaces of the front and rear boards 30A and 30B, respectively, and on the other hand, the engagement pins Pi and P2 are provided on the device main body side. Press to remove cartridge 3
A biasing device is provided for biasing the 0 to the storage position within the device body.

In FIG. 6, 101 is a stop plate that regulates the lower limit position of the retention bin P1 of the cartridge 30 attached to the inner surface of the front cover 100, and 102 is a stop plate that has an inclined surface 102A and is guided to slide downward by the action of a tension spring 103. When the pressure bonding plate 102 is inserted and the cartridge 30 is not inserted, the pressure bonding plate 102 is maintained at a position slightly lower than the illustrated position.

On the other hand, 112 is a crimp plate having an inclined surface 112A and guided to slide downward by the action of a tension spring 113, into which the cartridge 30 is inserted. If not, the pressure bonding plate 112 is kept at a position slightly lower than the illustrated position.

On the other hand, the developing unit 40 has a bent portion 42B at the center of the front surface of the support base 42 and a pair of bent portions 42C on the rear surface.
On the other hand, on the device main body side, there are locking pins P that fit into the locking holes 1 on the inner surfaces of the front cover 100 and the back side plate 110B of the main body, respectively.
3 and a pair of engagement pins P4 are attached.

To install the cartridge 30, first insert the retaining pin P2 on the rear surface into the elongated hole ill of the rear side plate 110B. When the engagement pin P2 is inserted into the elongated hole 111, it pushes the inclined surface 112A and slides the crimp plate 112 upward, but after the engagement, it is pressed against the lower end of the elongated hole 111 by the pressing force of the crimp plate 112, As a result, the cartridge 30 receives a clockwise moment about the engagement position with the elongated hole Ill, and maintains its front surface at a position slightly higher than the horizontal state.

Therefore, the cartridge 30 is in an inclined position with the front side facing upward, and can be attached to and removed from the main body of the apparatus without interfering with the developing unit 40 installed below.

The cartridge 30 is automatically set in a predetermined storage position by closing the front cover 100, whereby the image forming surface of the photoreceptor belt 1 is set at a position that forms a predetermined development interval with each of the developing sleeves. be done.

That is, in the process of closing the front cover 100, the crimp plate 102 presses down the engagement pin Pi, which is located at a position slightly higher than the horizontal state, by the inclined surface 102A, and when the lid is closed, the crimp plate 102 crimp the engagement pin Pl as shown in the figure. It is held and supported between the plate 102 and the stop plate 101.

On the other hand, when installing the developing unit 40, first insert the retaining hole H of the rear bent portion 42B into the rear side plate 110B.
By fitting into the retaining pin P4 and supporting the bent portion 42B by the bent portion of the front side plate 110A, and then closing the front cover 100, the engaging pin P3 is fitted into the bent portion 42B. The developing unit 40 is fitted into the retaining hole H and set at a predetermined storage position within the main body of the apparatus.

As a result, the developing unit 40 is held horizontally and is in pressure contact with the cartridge 30, so that the abutting rollers of each developing device, which will be described later, are in pressure contact with the guide member 4, and the developing sleeves and the photoreceptor belt l 5 6 intervals are set. When the developing unit 40 is pressed against the developing unit 40, the abutting rollers of the respective developing sleeves are pressed against the curved surface of the guide member 4 due to the flexibility of the developing container itself and the elasticity of the compression spring 43 acting on the developing container 4I. It is pressed properly with a certain load.

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

FIG. 8 shows a cross section of the developing device 9. 9A is a developing sleeve containing a fixed magnet roller, which is held in place by a coaxial abutment roller 9B between it and the circumferential surface of the photoreceptor belt L. It is driven and rotated counterclockwise while maintaining the development interval. 90
A is a rigid and magnetic thin layer forming member that is pressed against the developing sleeve 9A with a predetermined load without the presence of developer. Reference numerals 90B and 90C are a pair of toner conveying screws having a screw structure and conveying and circulating the developer in mutually opposite directions, which function to send the toner and carrier sufficiently stirred and mixed as the main developer to the developing sleeve 9A. .

The toner conveying screw 90B and the toner conveying screw 90C are members that also serve as stirring members that rotate in opposite directions, and the toner and carrier conveyed to the back side by the thrust of the toner conveying screw 90B are transferred to the toner conveying screw 90C. The toner is moved to the side and is conveyed to the front side of the drawing by the thrust, and the toner and carrier are mixed therebetween to form a homogeneous developer that is triboelectrically charged and adheres in a layer on the eight circumferential surface of the developing sleeve 9.

This developer layer, which forms a thin layer by adhering to the circumferential surface of the developing sleeve 9A, forms a latent image on the circumferential surface of the photoreceptor bell 1-1, which is conveyed clockwise in the developing area, by the above-mentioned development interval. A toner image is formed by reversal development in a non-contact manner.

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

The developer that has consumed the toner components has a high carrier ratio and is conveyed by the developing sleeve 9A to the scraper 90.
According to step 1), q11 is separated and collected, and a developer having a high ratio of 'Il> and toner is mixed.

Note that the main body of the apparatus includes the paper feed guide 15. Timing roller 17. Fixing roller 18. One member or roller of each pair of paper ejection rollers 19 and the transfer device 12,
It is supported by an openable and closable horizontal cover 200 that forms the left side of the main body, and when a jam occurs in the transfer material, the horizontal cover 100 is opened as shown by the dashed line in FIG. 9 to remove the transfer material. The structure is such that processing such as these can be easily performed. The horizontal cover 200 may also have a support shaft 200A provided at the upper part of the main body so as to be opened from below.

[Effects of the Invention] The present invention incorporates the cartridge and the developing device group by retracting and separating the process cartridge housing the belt-shaped image forming body from the developing device group using an extremely simple mechanism and easy operation. This allows the developing units to be freely attached to and removed from the main body of the device without interfering with each other, and as a result, each image forming means can be maintained easily, making it possible to consistently obtain high-quality images. An image forming apparatus is now provided.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional configuration diagram of a color image forming apparatus of the present invention, FIG. 2 is a block diagram showing an image forming system, and FIGS. 3 and 4 are front views of a process cartridge and a developing unit housed in the apparatus. , FIG. 5 is a perspective view of the front cover of the device, FIGS. 6 and 7 are sectional views of the cartridge and unit, FIG. 8 is a sectional view of the developing device, and FIG. 9 is a side view of the device. A configuration diagram of the cover. 1... Photoreceptor belt 4... Guide member 6...
Charger 7...Laser writing system unit 8.9, to, 11...Developer 8A, 9A, lOA, llA...Developer sleeve 12.
...Transfer device 13...Cleaning device 14
...Paper feed cassette 17...Timing roller 1
8...Fixing roller 9 0 30...(Process) car 3OA (30B)...Substrate 40...Developing unit 42...Support stand 100...Front cover 102.112...Crimping plate 110A (IIOB)...Side plate 200...Horizontal cover Pl, P2, P3, P Triangle 35...Handle 41...Developer container 43...Compression spring 10)...Stop Plate 103.113...Tension spring ill...Elongated hole H...Retaining hole 4...Retaining pin

Claims (2)

[Claims] (1) In a color image forming apparatus in which a plurality of developing devices are disposed facing each other on the lower periphery of a moving belt-like image forming body stretched between two rotating rollers disposed in the horizontal direction, A color image forming apparatus comprising: means for moving the belt-shaped image forming member upwardly away from the plurality of developing devices; and means for moving the belt-like image forming member in parallel in a direction perpendicular thereto. (2) The color image forming apparatus according to claim 1, wherein the plurality of developing units whose interference is released can be taken out after the belt-shaped image forming member is moved upward.