JPH02294672A - Color image forming device - Google Patents

Abstract

PURPOSE:To stabilize the quality of color and to make a device compact by adopting a process cartridge for color and appropriately arranging an image forming equipment. CONSTITUTION:A photosensitive drum 2, an electrostatic charger 3, a color developing unit 4, a cleaning device 10, a discharged toner collecting container 15 are included in the process cartridge 1. The developing unit 4 is integrated with respective developing devices, a Y developing device 5, an M developing device 6 and a C developing device 7, by mutually using a part of the wall surface in common. The respective developing devices 5-7 are provided with developing rolls 5a-7a, stirring rolls 5b, 5c-7b, 7c and layer thickness regulating rolls 5d-7d. The developing roll and the stirring roll are vertically arranged in the developing device. The respective developing devices are arranged below the photosensitive drum 2 so that they surround the circumferential surface of the photosensitive drum. Thus, the quality of a color image is stabilized and the device is made compact.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color image forming apparatus such as a color printer or a color copying machine, and particularly to a color image forming apparatus such as a color printer or a color copying machine, and in particular, it is possible to stabilize color quality by adopting a color process cartridge and appropriately arranging image forming equipment. The present invention relates to a color image forming apparatus that can be made smaller and more compact, and that can also meet the demand for black and white images.

[Conventional technology]

Conventional image carrier drum, yellow (Y). Magenta (M)
．． A color image forming system that includes a color process cartridge that integrally includes a group of color developers such as cyan (C), a cleaning device, etc., and a black and white process cartridge that is replaceable and includes a black (BK) developer. A device is known, for example, as described in Japanese Unexamined Patent Publication No. 58-72159.

[Problem that the invention seeks to solve]

However, in the color image forming apparatus described in the above publication,
During image formation, when changing from color to black and white or from black and white to color, a dedicated cartridge must be replaced each time, making operations complicated, costly, and time-consuming. There were some drawbacks, such as:

However, with the spread of printers, copiers, etc., there is a demand for smaller and lighter devices, and especially with colorization, it has become important to make devices more compact. However, in the color image forming apparatus described in each of the above-mentioned publications, the arrangement of the plurality of developing devices, transfer means, and other image forming devices is not necessarily appropriate;
This sometimes hinders the compactness of the device and the stabilization of color quality.

[Means for solving problems]

(Object of the Invention) The present invention has been proposed in view of the above circumstances! The purpose of this product is to stabilize the quality of color images by adopting a color process cartridge, to make the device more compact by optimizing the arrangement and configuration of the image forming equipment, and to make it easier to process color images. An object of the present invention is to provide a color image forming device that can easily convert an image into a black and white image without being restricted by cartridges.

(Structure and operation of the invention) The above-mentioned object is to provide an image bearing drum, a charging device on its periphery, a developing device group including a color toner developing device and a black toner developing device, a cleaning device, and a transfer paper transfer means. In the color image forming apparatus, the color toner developing device is integrated with the image bearing drum and the cleaning device to form a process cartridge cartridge that can be freely inserted into and removed from the device main body, and the black toner developing device is installed on the device main body side. This is achieved by a color image forming apparatus in which the developing device group including the color toner developing device and the black toner developing device is disposed below the image bearing drum, and the transfer conveyance means is disposed above the image bearing drum.

The color image forming apparatus of the present invention mainly includes an image bearing drum, a charger, Y, M, and C developing devices, a cleaning device #. J: A waste toner collection container, etc. is integrally contained within the process cartridge, and the cartridge is removably installed in the main body of the apparatus, and a BK developer is independently installed in the main body of the apparatus in a removable manner. There are some characteristics. With this configuration, by adopting a process cartridge, the quality of color images can be stabilized, and the device can be made more compact, and the BK developer can be used without being restricted by the process cartridge.
It can be inserted and removed freely according to toner consumption or developer fatigue.
It became replaceable, making it possible to stably supply large amounts of black and white images in addition to color image formation.

Further, in the color image forming apparatus of the present invention, Y, M
, C and BK developing units are arranged below the image bearing drum, and the transfer paper transfer/conveying means is arranged above,
It is characterized by the stabilization and compactness of the device configuration as well as the improvement of the quality of color or monochrome images.

The group of developing devices is vertically arranged so as to surround the outer periphery of the image carrier drum, and in particular, the Y, M, and C color developing devices have an integrated unit structure that shares a part of the wall surface with each other. It is preferable that The developer used in the Fuki developing device group may be a one-component developer containing magnetic toner as a main component or a two-component developer containing non-magnetic toner and a magnetic carrier.

However, the two-component developer is preferred in order to obtain a clear color tone of the colorant contained in the toner.

The above. The process cartridge continues to be used for image formation until it reaches its usable limit due to fatigue of the carrier in the developer or the photoreceptor, and is inserted/removed/replaced when the usable limit is reached. Further, since there is not enough space in the developing chamber of the color developing device in the cartridge, it is preferable that toner be supplied to the color developing device from a toner replenishing device provided on the front or rear side of the device. The BK developing device installed on the main body side of the device has a toner chamber inside the developing device, and toner is replenished from the toner chamber into the developing chamber, and the developing device can be inserted and removed as the toner is consumed. It's okay. Further, toner may be replenished by inserting and removing a toner container filled with toner into the developing chamber, and the developing device may be inserted and removed as the developer, particularly the carrier, becomes fatigued.

Furthermore, a toner replenishment hopper may be provided to replenish i-toner into the developing chamber from the outside.

By arranging the developing device group as described above, the process cartridge can be made more compact, and the arrangement is structurally stable.Also, thick triboelectric charging is performed by stirring and mixing the developer, and excellent developing performance is achieved. It is possible to obtain high-quality color images. Furthermore, since the transfer and conveyance means for the recording transfer paper is disposed above the image carrier drum, there are advantages such as no contamination of the transfer paper due to leakage or scattered toner from the developing device group.

In addition, in order to efficiently continue producing color or monochrome images over a long period of time, it is preferable to provide a waste toner collection container in the process cartridge, and use a cleaning device to scrape and collect residual toner on the surface of the image bearing drum. The obtained waste toner is preferably collected into the collection container by a waste toner transport pipe having, for example, a screw conveyor or a coil. Instead of the waste toner collection container, the waste toner may be collected in the cavity of the image carrier drum.

Next, to switch between monochrome image formation and color image formation during image formation, store the color image formation process and monochrome image formation process in the program memory in advance, and select either process by operating the program operation keys provided on the main body of the apparatus. Image formation is performed by the selected process via the control device.

(Example) FIG. 1 is a sectional view of a color printer explaining this example. In the figure, l denotes a process cartridge, and the cartridge contains a photosensitive drum 2, a charger 3, a color developing unit 4, a cleaning device lO, and a waste toner collection container l5. In the developer unit 4, each of the Y developer 5, M developer 6, and C developer 7 is integrated with each other by sharing a part of the wall surface with each other. Further, the developing rollers 5a, 6a, 7a. Stirring roll 5
b, 5c, 6b, 6c, 7b, 7c and layer thickness regulating rolls 5d, 6d, 7d. These developing rollers and stirring rolls are arranged vertically in the developing device, and each developing device is arranged below the photoreceptor drum 2 so as to surround the circumferential surface of the photoreceptor drum. Ru.

The cleaning device 10 includes a waste toner collection pipe 10a,
[z--Jnl"'ilm IOb, cleaning brake
The waste toner scraped off by the blade toe is collected in a collection tube tOa via a waste toner collection film IOb. The collection pipe 10a is connected to one end of the waste toner transport pipe l2 installed at the front of the device, and the other end (the collection pipe 1.5a of the waste toner collection container 15 is connected to the collection pipe 1.5a of the waste toner collection container 15, and the cleaned waste toner is collected from the front of the apparatus. The waste toner is collected into a collection container l5 via a waste toner transport pipe l2.

Next, the BK developing unit 8 is detachably installed in the main body of the apparatus separately from the process cartridge 1, so that it can meet the demand for large-scale black and white image formation without being restricted by the cartridge. , is an important feature of the present invention.

Next, 20 is a laser optical device for image exposure, which includes a polygon mirror 20a1, a collimating lens 20b1, reflection mirrors 20c, 20d, 20e, an f-theta lens 20f1, and a dustproof glass 20g; be.

Semiconductor laser light modulated by an external video signal is introduced into the optical device 20, and image exposure light L is irradiated from the device 20 onto the photoreceptor drum to form an electrostatic latent image.

Reference numeral 30 denotes a paper feed cassette, and the transfer paper P fed from the cassette 30 by a paper feed roll 3l is transported to the transfer area via a transport path 32 and upper and lower rolls 33a and 33b of the transport roll 33.

40 is a transfer conveyance device, 40a is a transfer conveyance bell}, 4
0b and 40c are drive rollers of the belt 40a, 40d
is a vent tension roll, and 40e is a transfer pole.

4H Press roll with fixing device 4. The transfer paper after fixing is discharged to a paper discharge tray 43 by the upper and lower rollers 42a and 42b of the delivery roll 42.

The main body of the device is the upper roller 33 of the transfer paper transport roll 33.
Pressure roller 4 of a1 transfer conveyance device 40 and fixing device 4l
1a, an upper casing K containing the upper roll 42a of the delivery roll 42; a lower casing K containing the process cartridge and cartridge 1;
For p. - Open P2 as a boundary and transfer/
It is possible to dispose of jams that occur in the conveyance system.

Also, the insertion and removal of the paper feed cassette 30 is performed using the side cover K that includes the paper ejection tray 43.
3 through the boundary Pz-Pt. Also, jam processing 1 in the transfer paper conveyance process is performed by opening the side cover K6 including one side of the conveyance path with Pg Pi as the boundary.

Further, an example of inserting and removing the process cartridge 1 from the main body of the apparatus will be explained with reference to FIG. 1 and 2rgJ.

In the figure, a lower housing K containing a process cartridge L is shown.
, the upper casing K is opened with P, - P as the boundary and centered around the axis Q. Next, move the front door A to the axis Q
, grip the handle M with the handles M in the center and tilt it toward you to open the front of the main body of the apparatus, and while moving the lower end protrusions 11a and llb of the process cartridge L along the guide rails 12a and 12b, remove the cartridge. The l is pulled out to the front and replaced. Next, BK, which is one of the features of the present invention,
Similarly, in the case of the developing unit 8, the drawer is replaced while the front door A is folded forward and the retainers 13a and 13b fitted to the rails are slid along the rails 14aj; and 14b.

Inside the BK male imager 8, there are a developing roll 8a and a stirring roll 8.
b, 8c, and layer thickness regulating rolls 8d and 8e.

I; The Y, M, and C color developing devices 5, 6.7 are provided with a toner replenishing device 5e.7 provided at the rear of the device. Toner is replenished from 6e and 7e.

Image formation in this example was performed in the following manner using the color image forming apparatus having the above configuration. The color process specification key 48 of the process specification keys 47 is operated in advance to read out the color process stored in the memory 45, and the CP
A color process is specified via tl46, and Y, M in the process cartridge is specified based on the color video signal.
, a C color developer and a BK developer attached to the main body of the apparatus.

First, during the first rotation of the photosensitive drum 2 with the cleaning device released, the charger 3 applies a uniform charge of -700V to the drum 2, and then the Y signal, which is the first video signal, applies a uniform charge to the photosensitive drum 2. The laser beam oscillated from the laser device 22 is modulated, and the obtained modulated laser beam passes through the laser optical device 20 including the polygon mirror 20a to f! 'f The Y developing device 5 is imagewise exposed to form an electrostatic latent image on the drum 2, contains a two-component developer, has a DC component of -600V, an AC component of 3KHz, and has a developing bias of 500V applied. The image was developed in a non-contact, reversal manner, and a Y toner image was formed on the photoreceptor drum.

The photoreceptor drum 2 is then rotated, and the charger 3 charges it to -70
After being recharged to 0 V, image exposure with a laser beam modulated by the M signal and similar development using the M developing device 6 were performed to form an M toner image superimposed on the Y toner image. Similarly, in the third and fourth rotations of the photosensitive drum 2, image exposure by laser light modulated by the C signal and BK signal, and reversal development by the C developer 78 and the BK developer 8 are repeated, and the navigation Y A color toner image is formed by superimposing a C toner image and a BK toner image on the M toner image.

The M toner image, the C+-toner image, and the BKI-toner image were formed under the same image forming conditions as the Y toner image.

Next, according to a predetermined image forming program, the transfer paper is sent out from the paper feed cassette 30 by the paper feed roller 3l, and is conveyed to the transfer area T by the conveyance roller 33 and the transfer belt 40a via the conveyance path 32. The transfer area T
Transcription pole at. 10e, the color toner image on the photosensitive drum 2 is transferred onto the transfer paper, heat-fixed by the heat roll old b of the fixing device 41, and discharged face down to the paper discharge tray 43 by the paper discharge roll 42. . After the colored toner image was transferred to the transfer paper, the cleaning device was turned on to clean the remaining toner on the photoreceptor drum 2 and prepare for the next image formation. The above cycle was continuously repeated iooo times to form a color image.

During this time, the color 1 toner is supplied to the toner replenishing device 5 in FIG.
e (Y). 6 e (M). 7s (C), and the BK} toner is stored in the toner chamber 8e in the BK developing device 8.
High density, clear color images were obtained from beginning to end because of the stable supply from the beginning.

Next, the monochrome (black) process specification key 47 of the process specification key 47 was operated to change the image forming process to a monochrome image forming process, and image formation was performed using the BK developer 8 based on the monochrome video signal. .

With the cleaning blade foe turned on,
A uniform charge of -700V is applied to the photosensitive drum 2 by the band 1!63, and then the laser beam oscillated from the laser device 22 is modulated by the BK video signal, and the modulated laser beam passes through the laser optical device 20. An electrostatic latent image was formed on the drum 2 through imagewise exposure. This electrostatic latent image is
A BK containing a two-component developer, with a DC component of -600V and an AC component of 3K}Iz, and a bias of 500V applied.
The developing device 8 developed the image in a non-contact, reversal manner, and a BK toner image was formed on the photosensitive drum 2. This BK toner image was transferred and fixed onto the transfer paper fed from the paper feed cassette 30 to form a BK image, and after the transfer, the photosensitive drum IO was cleaned by the cleaning device IO.

The above cycle was repeated 5,000 times to form a black and white image. During this time, the BK developer was inserted and removed and replaced independently of the process cartridge 1, and image formation continued.
A clear image was obtained.

Furthermore, in this embodiment, image formation over a long period of time was made possible by collecting the waste toner scraped off by the cleaning device 1O into the collection container 15.

Although a color printer was used in the above embodiment, it can be combined with a color scanner to form a color copying machine, and this case is also included in the present invention.

C. Effects of the Invention] As is clear from the above description, according to the color image forming apparatus of the present invention, compactness of the apparatus 8 and stable arrangement of each image forming device can be achieved. This can be achieved with a single touch without being subject to any restrictions, and it also has the effect of guaranteeing stable image quality.

[Brief explanation of drawings]

FIG. 1 is a sectional view illustrating the structure of a color printer according to an embodiment, and FIG. 2 is a perspective view of the color printer shown in FIG. 1. ■... Process cartridge 2... Photosensitive drum 3... Charger 4... Color developing unit 5, 6. 7...Y, M, C developing units 8...B
K developer lO...Cleaning device l5...
・Waste toner recovery device R 20...Laser optical device 22
... Semiconductor laser device 30 ... Paper feed cassette 40
...Transfer/conveyance means 45...Memory 46...CPU 47...Process key Fig. 2

Claims (1)

[Scope of Claims] A color image forming apparatus comprising an image bearing drum, a charging device, a group of developing devices including a color toner developing device and a black toner developing device, a cleaning device, and transfer paper transfer means on the periphery thereof, A color toner developer is integrated with an image carrier drum and a cleaning device to constitute a process cartridge that can be inserted into and removed from the apparatus main body, and the black toner developer is disposed on the apparatus main body side and is attached to the image carrier drum. On the other hand, a color image forming apparatus characterized in that a developing device group including the color toner developing device and the black toner developing device is disposed below, and the transfer conveyance means is disposed above.