JPH02262674A - Color image forming device - Google Patents

Abstract

PURPOSE:To prevent a developer from falling and entering a developing device by providing a toner recovery box in front of a process unit formed by uniting an image formation body, a developing device group, and a cleaning device together. CONSTITUTION:Respective devices, i.e. four developing devices which contains the image formation body, a cleaning device 40 with a pressing and releasing mechanism for the image formation body, and an electrostatic charger are stored in one process cartridge and unitized, and the process cartridge can be inserted into and extracted from a device main body. Further, the process cartridge 3 is equipped with toner supply boxes 36A - 39A in front of the corresponding developing devices and a toner recovery box 47 is provided further in front of them. Then waste toner which is removed by the cleaning device 40 is conveyed and collected in the toner recovery box 47 with the thrust of a toner conveyance screw 48 running through a toner conveyance pipe 49. Consequently, toner is supplemented and the waste toner is processed without making hands and clothes dirty.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a color image forming apparatus using electrophotography, and the present invention relates to a color image forming apparatus that is miniaturized, has improved maintenance performance, and has improved jam processing performance. , regarding.

[Conventional technology]

An electrophotographic image forming apparatus that forms a multicolor image such as a full color image or a functional color image includes a charger that charges a photoreceptor drum that is an image forming member, an image exposure unit that exposes an image to the photoreceptor drum, A developing device that develops the electrostatic image on the photosensitive drum with toner, a transfer device that transfers the toner image on the photosensitive drum onto recording paper, and the like are arranged around the photosensitive drum.

Among these, the developing units in full-color electrophotographic image forming apparatuses are comprised of three or four developing units each containing yellow (Y), magenta (M), cyan (C) toner, and sometimes black (BK) toner. It consists of a developing device, and while the photosensitive drum rotates three or four times,
Yellow (Y), magenta (M), cyan (C), and black (BK) toner images are formed on the photoreceptor drum, and these toner images are transferred to recording paper to obtain a full-color image. ing. When using such an image forming method, the color image forming apparatus can be made compact by making three or four developing units thin and arranging them close to each other.

Japanese Unexamined Patent Publication No. 61-55661 proposes a color image forming apparatus using such an image forming method, in which latent images are formed by three exposure devices corresponding to three developing devices, and a photoreceptor drum and The developing device and the cleaning means are integrated into a unit and can be taken out from the main body of the apparatus. In addition, a patent application published in 1982-32 used two exposure devices, arranged the developing devices one on top of the other, and made it into a unit that could be taken out from the main body of the device.
It is described in the specification of No. 0596.

The above-mentioned Japanese Patent Application Laid-Open No. 61-55661 and Japanese Patent Application No. 1983-
The color image forming apparatus described in the specification of No. 320596 contributes to improving the maintainability, but when the unit is inserted or removed, Jj! It was easy for the image agent to crumble or get mixed in.

Furthermore, Japanese Patent Application Laid-open No. 72159/1983 describes an example in which the area around the photosensitive drum is made into a unit for a color image forming apparatus that uses a transfer drum to transfer each color toner image to a recording paper.

[Problem that the invention seeks to solve]

However, in the color image forming apparatus described in JP-A-58-72159, the (+) image forming section extends not only around the photosensitive drum but also onto the transfer drum.

(2) The circumferential speed and gap between the photosensitive drum and the transfer drum must be maintained with high accuracy.

(3) A release mechanism is required to take out the photoreceptor drum.

As described above, in a color image forming apparatus using a transfer drum, the mechanism is not only complicated and expensive as described in (2) and (3) above, but also the image forming apparatus is difficult to form, as in a monochrome image forming apparatus that does not require a transfer drum. Since the means are not concentrated around the photoreceptor, the advantages of unitization (process unit) in the image forming section cannot be fully obtained.

The present invention improves maintainability by integrating the developing unit, the image forming body, and the cleaning means, or by forming a cartridge structure in which two of them are integrated and the remaining one is independently insertable and removable. , and to prevent the developer from spilling outside or getting mixed into other developing units when a plurality of developing units are combined into a unit and the process unit is inserted into and removed from the main body of the apparatus. Another object of the present invention is to provide a color image forming apparatus which facilitates jam handling when a conveyance failure occurs in the conveyed recording paper.

Another object of the present invention is to reduce the size of a color image forming apparatus using a process of forming a composite toner image such as a color toner image made of toners of multiple colors on the surface of a photoreceptor drum and transferring the same to recording paper at once. In addition, in order to make the photoreceptor drum more compact, image forming means such as multiple developing devices and cleaning means are concentrated around the photoreceptor drum. On the other hand, it is an object of the present invention to provide a color image forming apparatus which is arranged so that the left and right weight balance is maintained and has excellent operability such that a process unit can be easily inserted and removed from the apparatus main body.

[Means for solving problems]

The above purpose is to form a plurality of toner images on a rotating image forming body by repeating charging, image exposure and development multiple times on the image forming body, and transfer the toner images to recording paper. In a color image forming apparatus for transferring, an image forming body, a developing device group provided below the image forming body, and a cleaning device are integrated to form a process unit, and the toner collected from the cleaning device is This is achieved by a color image forming apparatus characterized in that a toner collection box for accommodating the toner is provided in front of the Zorocess unit.

〔Example〕

An embodiment of the present invention is shown in FIGS. 1 to 5.

FIG. 1 shows an embodiment in which the present invention is applied to a printer.

The printer has a Talamusiel-type structure divided into an upper casing 1 containing a transfer belt and an apparatus main body 2 containing a process unit, and the upper casing 1 is opened at a predetermined angle by a hinge connected to the apparatus main body 2. and can be held as
Further, in the closed state, it is integrated with the main body 2 of the device by means of a locking metal fitting.

An image forming body 30 constituting an image forming section of the printer, developing devices 36, 37, 38, and 39 containing yellow, magenta, cyan, and black developers, and a cleaning device having a pressure releasing mechanism for the image forming body. 40 and charger 35
Each of the equipment is housed in a unitized process cartridge 3 and is removably inserted into the apparatus main body 2 via a pair of guide members 4 that engage on the left and right outer surfaces of the unit. However, in particular, in the present invention, the developing units 36, 37, 38, 39 are disposed below the image forming member 30 and arranged vertically and sequentially from the upstream direction of the image forming member 30 so as to face the surface thereof.

That is, the process cartridge 3 is inserted and mounted in the depth direction of the apparatus main body 2 by holding the handle provided on the front side and being engaged with the guide member 4, and when pulled out toward the front, the engagement of the guide member 4 is released and the process cartridge 3 is inserted into the apparatus main body 2. However, since each developing unit is kept with its opening facing upward, there is no possibility of the developer leaking out and falling or getting mixed into other developing units. nothing happens.

The printer has a laser writing system unit B in a space on the side of the process cartridge 3, and a recording paper conveying surface in a part above the process cartridge 3 that spans both the upper housing 1 and the apparatus main body 2. We have set up
The image forming body 30 is subjected to laser scanning by the laser writing system unit B from diagonally downward, and a color toner image formed on the circumferential surface thereof is superimposed and transferred to the lower surface of the recording paper.

The process of color image copying by the printer is performed as follows.

First, the formation of a multicolor image in this embodiment is performed according to the image forming system shown in FIG. That is, the data obtained from the color image data input unit (FIG. 4 (a)) in which an image sensor scans the original image is input to the image data processing unit (
Image data is created through arithmetic processing in FIG. 4(b)), and is then stored in the image memory (FIG. 4(c)). Then, the image memory is taken out during recording and transferred to the recording section (fourth
For example, the image data is input to the color image forming apparatus shown in the embodiment of FIG. 1 as shown in 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 B, the laser writing system unit B outputs a laser beam generated by a semiconductor laser (not shown). is rotated and scanned by a polygon mirror 32 rotated by a drive motor 31, the optical path is bent by a mirror 34 via an fθ lens 33, and the peripheral surface of the image forming body 30 is charged in advance by a charger 35 serving as a charging means. It is projected upward and forms a bright line.

On the other hand, when scanning is started, the beam is detected by the index sensor, modulation of the beam by the first color signal is started, and the modulated beam scans the circumferential surface of the image forming body 30. Therefore, a latent image corresponding to the first color is formed on the circumferential surface of the image forming body 30 by the main scanning by the laser beam and the sub scanning by the rotation of the image forming body 30. This latent image is developed by a developing device 36 loaded with yellow (Y) toner (a image medium) of the developing means, and a toner image is formed on the drum surface. The obtained toner image passes under a cleaning device 40, which is a cleaning means, which is separated from the peripheral surface of the image forming body 30 while being held on the drum surface, and enters the next copy cycle.

That is, the image forming body 30 is charged again by the charger 35, and then the second color signal output from the signal processing section is input to the writing system unit B, and the second color signal is inputted to the writing system unit B, and the second color signal is inputted to the writing system unit B. In the same manner, writing is performed on the drum surface to form a latent image.

The latent image is developed by a developer 37 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 38 has cyan (C) toner, and forms a cyan (C) toner image on the drum surface based on a control signal generated by the call processing section.

Furthermore, 39 is a developing device having black toner, and a black toner image is superimposed and formed on the drum surface by the same process. Direct current or even alternating current bias is applied to each sleeve of each of these developing devices 36, 37, 38 and 39, and jumping development is performed using a two-component developer serving as a developing means to form an image with the substrate grounded. body 30
Development is now possible without contact.

The color image thus formed on the circumferential surface of the image forming body 30 is re-charged by the charger 9 and transferred to the lower surface of the recording paper fed from the paper cassette C via the paper feed roller and the paper feed guide in the transfer l54Q. transcribed.

That is, after this multicolor toner image is charged by the pre-transfer charger 9 to be easily transferred, the transfer belt 50, which has been rotating since the start of transfer, is brought into contact with the image forming body 30, and the paper is fed from the paper feed cassette C. The image is transferred to the supplied recording paper via the roller 12 and the timing roller 13 in synchronization with the image formation.

The structure of the transfer belt 50 is such that an elastic layer with a thickness of 0.5 am is provided on the outer periphery of a comb belt containing conductive cloth as a base, and an insulating layer (dielectric layer) with a thickness of 50 μm is further provided on the outer periphery. The transfer belt 50 comes into contact with or separates from the image forming body 30 as the roller 60a rotates by driving the roller 60a, and the roller 60b moves up and down. The transfer belt 50 is charged by a charging brush 65 or a corotron.
1.5KV~3. Transfer is performed by applying a transfer charge having a polarity opposite to that of the toner of about OKV.

Note that 66 is a cleaning device for the transfer belt that cleans the top of the transfer belt 50.

On the other hand, the blade 40A of the cleaning device 40 comes into contact with the image forming body 30 from which the recording paper has been separated from the drum surface to remove the remaining toner, and after that, the image forming body 30 is separated from the drum surface again and is replaced with a new one. Enter the process of color image format.

In this way, the recording paper is conveyed horizontally over the top of the process cartridge 3, and the transfer surface is also facing downward, so even if toner spills or scatters from the cleaning device R40, it will not stain the image surface. I never get to the point where I do it.

FIG. 2 is a front view of the process cartridge 3 taken out from the main body of the apparatus, and the handle 5 on the front side is used to take it out.

In the process cartridge 3, the developing units 36, 37, 38, and 39 are distributed to the left and right with respect to the center line of the image forming body 30, that is, the developing units 36, 37, 38, and 39 are separated from each other across the axis of the image forming body 30. 37 is on the right side, and developer unit 38 and 3
9 are arranged at symmetrical positions on the left side.

As a result, the weight of the process cartridge 3 is well balanced on the left and right sides, making it easier to handle, and it is also possible to make the developing devices placed in symmetrical positions on the left and right sides have a common structure.

Further, the process cartridge 3 has toner replenishment boxes 36A, 37A, 38A containing toner of a specific color to be supplied to each developing device at a position on the front surface corresponding to each developing device 36, 37, 38, 39 housed inside.
, 39A, and a toner collection box 47 for collecting waste toner removed by the cleaning device 40 is provided in front of each toner supply box.

Since the toner collection box 47 can have a large volume that covers the entire surface of each toner supply box, it is possible to accommodate a large amount of waste toner, and the frequency of disposal can be significantly reduced. be.

FIG. 3 shows a cross-sectional structure of the inside of the toner collection box 47 and the connecting portion between the developing device 37 and the toner replenishment box 37A as viewed from the arrow AA in FIG.

The developing device 37 is provided concentrically at both axial ends of the developing sleeve 3703; it is positioned so as to press against the image forming body 30 with a pair of abutting rollers 3703A, and an extension of its housing 3702 is connected to the toner replenishing box 37A. connected to the bottom of the

The developing device 37 is equipped with a pair of toner conveying screws that agitate the contained toner by using propulsive forces in opposite directions, as will be described later. Toner transport screw 370
7 is extended to the inside of the toner supply box 37A.

Therefore, when the developing sleeve 3703 starts rotating, the toner conveying screw 3707 rotates via the gear pair Gl, and when the toner concentration decreases, the toner supply box 3 rotates via the electromagnetic clutch MC.
The sponge roller 37B included in the sponge roller 37B rotates and drops the stored toner, and the toner is transported into the developing device 37 by the driving force of the toner transport screw 3707.

On the other hand, the toner collection box 47 has an opening on its upper surface connected to the bottom of the cleaning device 40 via a toner conveying pipe 49, and a toner conveying screw that passes the waste toner removed by the cleaning device through the toner conveying pipe 49. Toner collection box 47 by the thrust of 48
Transport and collect within.

Therefore, the work of replenishing each toner to each toner supply box and the work of disposing of the waste toner collected in the toner collection box 47 can both be performed on the front side of the process cartridge 3. There is no need to remove the toner from the main body of the apparatus, and toner can be easily replenished or the box replaced simply by opening the upper casing l.

Note that the toner conveying pipe 49 includes a toner conveying screw 4.
A connecting pipe member molded from a synthetic resin material with high lubricity is used so as not to provide resistance to the operation of the connecting member 8.

Further, in FIG. 3, it is also possible to limit the height of the toner collection box 47 while increasing the height of the toner replenishment box 37A, so that a part of it can be expanded until it reaches the upper part of the toner collection box 47. Accordingly, the amount of replenishment toner that can be accommodated can be further increased. In this case, the toner conveying pipe 49 is connected at the front of the toner collection box 47, and work such as replacing the box for waste toner processing is performed by opening the front door of the main body of the apparatus.

Each developing device used in each embodiment contains a developer of a specific color, and its structure and function are the same as the developing device 37 of the printer described below with reference to FIG. be done.

In FIG. 5, 3702 is a housing, 3703 is a developing sleeve, 3704 is a magnet roller, 3705
is a rigid and magnetic thin layer forming member 3705 that regulates the amount of developer;
It is pressed against 703 with a constant load without the presence of developer. Reference numerals 3707 and 3708 are a pair of toner conveying screws having a screw structure and conveying and circulating the developer in mutually opposite directions, and 3709 is a supply roller.

The toner supplied from the toner supply box 37^ is transferred to one of the toner conveying screws 370, which rotates in the direction of the arrow.
7 and the other toner conveying screw 3708 that rotates in the opposite direction so as to overlap with each other, supply roller 3709 as the upper developer that is sufficiently stirred and mixed with the carrier.
is sent to the developing sleeve 3703 via.

The toner conveying screw 3707 and the toner conveying screw 3708 are members that also serve as stirring members that rotate in opposite directions.
The toner and carrier transported to the back side by the thrust of 8 are transferred to the toner transport screw 3707 side and transported to the front side of the drawing by the thrust, and the toner and carrier are homogeneously charged by friction due to the mixing action of the toner and carrier during this time. The developer is formed into a layer and adheres to the circumferential surface of the developing sleeve 3703 by a sponge-like supply roller 3709 that rotates in the direction of the arrow.

In this embodiment, a fixed magnet roller 3704 and a developing sleeve 3 rotating in the direction of the arrow (clockwise) on the outside thereof
This thin developer layer adhered on the surface 703yIi abuts the latent image on the image forming body 30 rotating in the direction of the arrow in the development area 3712, and is developed in a non-contact manner by reducing the distance formed by the rollers 3703A. It was configured to form a toner image.

During this non-contact development, a developing bias containing an AC component is applied to the developing sleeve 3703 from a power source (not shown), and only the toner in the developer is selectively transferred to the surface of the latent image on the image forming sleeve 3703. attached.

The developer that has consumed the toner component has a high carrier ratio, is transported by the developing sleeve 3703, is peeled off and collected by the scraper 3710, and is again mixed with a developer that has a high toner ratio.

〔Effect of the invention〕

The present invention provides a process cartridge in which process equipment mainly including an image forming body, a plurality of developing devices, a cleaning device, etc. in a color image forming apparatus is unitized, and is connected to each of the developing devices and the cleaning device. By centrally arranging a toner supply box and a toner collection box in the front of the process cartridge, a color image forming apparatus is provided that allows toner replenishment and waste toner disposal through extremely simple operations without staining hands or clothes. was to be provided.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional configuration diagram of a color image forming apparatus of the present invention, FIGS. 2 and 3 are a front view and a sectional view of a main part of a process cartridge housed in the apparatus, and FIG. 4 is a block diagram showing an image forming system. FIG. 5 is a sectional view of a developing device housed in the process cartridge. 3... Process cartridge 4... Guide member 5... Handle 30... Image forming body 36.37.38.39... Developing devices 36A, 37A, 38A, 39A... Toner supply box 37B ...Sponge roller 40...Cleaning device 40A...Blade 47...Toner collection box 4g, 3707.3708...Toner conveyance screw 49...Toner conveyance pipe 370
2...Housing 3703...Developing sleeve

Claims (2)

[Claims] (1) A rotating image forming body; charging, image exposure, and development are repeated multiple times on the image forming body to form a plurality of toner images on the image forming body, and the toner images are transferred to recording paper. In a color image forming apparatus, an image forming body, a developing device group provided below the image forming body, and a cleaning device are integrated to form a process unit, and the toner collected from the cleaning device is stored. A color image forming apparatus characterized in that a toner collection box is provided in front of the process unit. (2) The color image forming apparatus according to claim 1, wherein the toner collection box is arranged in parallel with a toner replenishment box that replenishes toner to the developing device.