JP2808305B2 - Color image forming equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus such as a color printer or a color copying machine, and more particularly, to the use of a disposable process cartridge to reduce the size, weight, and image quality of the apparatus. The present invention relates to a color image forming apparatus in which stabilization is achieved.

[Conventional technology]

Conventionally, for example, JP-A-58-72159 discloses a color process cartridge including an image carrier drum, a charger, a plurality of color developing units and a cleaning device,
A color copier having a black-and-white process cartridge containing a black (BK) developing device as a spare for the cartridge is known.

[Problems to be solved by the invention]

However, since the cartridge contains a plurality of color developing units, the cartridge becomes large,
The structure becomes complicated and expensive.

Therefore, in order to provide the cartridge with practicality in terms of cost at the time of disposable use, for example, image formation is continued until the use limit of the long-life image carrier drum is reached, and then the cartridge is replaced and discarded. Is preferred.

As a result of the improvement, the image carrier drum can withstand 50,000 to 100,000 image formations. On the other hand, in a color developing device, a two-component developer composed of a toner and a carrier is preferably used in order to obtain a clear color image, and the life of the carrier varies depending on the type of the carrier.
It is about 30,000. When a developer containing such a developer is contained in a cartridge, the cartridge is replaced on the basis of a developer having a short life, and its economy is lost.

Further, in the color copying machine described in the above publication, since a plurality of color developing units are provided in a lateral position with respect to the image carrier drum and are provided so as to accumulate, it is easy for color mixing of each color toner to occur, and the apparatus becomes unstable. It has disadvantages such as becoming. Further, since the transfer / transfer means of the transfer paper is left below the image carrier drum, there is a disadvantage that the transfer paper is liable to be contaminated by leakage and scattering of the toner from the developing device.

[Means for solving the problem]

(Object of the Invention) The present invention has been proposed in view of the above circumstances, and stabilizes the quality of a color image by employing a process cartridge including an image carrier drum and a cleaning device, but not including a plurality of developing devices. It is another object of the present invention to make the cartridge economical disposable use, and to optimize the arrangement and configuration of the image forming apparatus to reduce the size of the apparatus and improve the image quality.

(Constitution and Operation of the Invention) The object is to provide a color image forming apparatus having a charger, a plurality of developing units, a cleaning device, and a transfer unit on the periphery of an image carrier drum, wherein the transfer unit uses a transfer belt. A process cartridge integrally including the image carrier drum, a charger and a cleaning device is configured to be detachable from the apparatus main body, and the plurality of developing devices are provided on the apparatus main body side, and the image carrier drum The transfer belt is disposed below, the transfer belt is disposed above the image carrier drum, and when the process cartridge is inserted into or removed from the apparatus main body, the transfer belt is opened upward, and the plurality of developing devices are integrated. A color image forming apparatus, wherein the process cartridge is moved downward as an integrated developing device unit, and then the process cartridge is inserted into and removed from the front side of the apparatus main body. More achieved.

In the color image forming apparatus of the present invention, a charger, a cleaning device, and if necessary, a waste toner collecting container, etc. are integrally contained in a process cartridge around an image carrier drum, and the cartridge is removably inserted into the apparatus main body. The developing units for yellow (Y), magenta (M), cyan (C), and black (BK) are individually or individually removably mounted on the apparatus main body. With this configuration, it is possible to realize a low-cost disposable color process cartridge, and if necessary, convert the image from color to black and white using the BK developing device without replacing the cartridge. Is possible.

Further, the plurality of developing devices are arranged below the image carrier drum, and the transfer belt, which is a means for transferring and transferring the transfer paper, is arranged above, so that the center of gravity of the apparatus main body is located below and stabilized. In addition, even when toner leaks from the developing device or the cleaning device, the transfer paper is prevented from being contaminated. Further, since the developer agitator and the developing roll are vertically arranged in the plurality of developing devices, there is an advantage that the stirring and mixing of the developer and the triboelectric charging therewith are sufficiently performed to improve the image quality. Further, since each of the developing units is upwardly directed, there is an advantage in that the developer is less scattered and scattered and color mixing does not occur. The copy developing device is preferably provided with a toner supply device,
It is preferable that the image can be continuously formed until the usage limit of the carrier in the developer is reached.

In order to continue image formation efficiently, a waste toner collecting container is provided in the cartridge, and a cleaning device scrapes residual toner on the surface of the image carrier drum and collects and collects the waste toner, for example, using a screw conveyor or a spring coil. It is preferable that the waste toner is collected in the collection container by a waste toner transport pipe using the above. Further, instead of the waste toner collecting container, the waste toner may be collected in the cavity of the image carrier drum.

The plurality of developing devices are supplied with toner from a toner replenishing hopper provided in the apparatus main body or a toner replenishing cylinder inserted into and removed from a developing chamber of the developing device, and development for image formation is continued. The plurality of developing units may be replaced individually or as a unit depending on the usage limit of the carrier.

If necessary, the image formation can be changed from color to black and white or from black and white to color.For example, a color and black and white image forming program is stored in a memory in advance, and by operating keys on a panel provided on the apparatus main body. The image formation may be performed by selecting a corresponding program without being restricted by the process cartridge.

〔Example〕

1 and 2 are cross-sectional views of a printer for explaining the present embodiment, and FIG. 3 is a perspective view of the printer.

The printer has a clamshell structure divided into an apparatus main body 2 and an upper housing 1, and as shown in FIG. 2, the upper housing 1 can be opened at a predetermined angle (30 ° C.) with the rotation axis P as a fulcrum. When the cover is in the closed state, it is integrated with the apparatus main body 2 by a stopper (not shown).

The image carrier drum 30, the cleaning device 0, the charger 35, the pre-transfer charger 9, and the waste toner collecting container 47, which are a part of the image forming device of the printer, include the process cartridge 3.
The cartridge 3 is integrally contained in the apparatus main body 2.
It is removably inserted into the apparatus main body 2 via guide members 3A and 3B arranged at a horizontal position.

A Y developing device 36, an M developing device 37, a C developing device are provided on the lower surface of the image carrier drum 30 included in the process cartridge 3.
38, a BK developing device 39 is arranged so as to surround the image carrier drum 30, and the developing devices are integrated by sharing a part of an outer wall with each other, are included in a unit 45, and
Reference numeral 45 is removably inserted into the apparatus main body 2 via a guide member 46. The guide member 46 penetrates one end thereof,
And it is rotatable about an axis P ₂ which is supported by the apparatus main body 2. That is, the eccentric cam 47, which is normally fixed at a fixed position by the lock member 48, is released in the same direction by releasing the lock member 48 and rotating the handle 49 clockwise, and at the same time, the guide member 46 It is rotated downwardly to the axis P ₂ as the center, a developing unit 45 which is fitted to the guide member
Is separated from the image carrier drum 30.

Meanwhile the To detach the process cartridge 3 from the apparatus main body 2 is upwardly open upper housing 1 including a transfer belt 50 around the axis P _1, then the front door of FIG. 3 H
Is opened to H 'by the knob M, and the guide member 46 of the developing unit 45 is rotated downward in accordance with the above-mentioned procedure, thereby separating the developing unit 45 from the image carrier drum. Next, the process cartridge 3 is pulled out toward the front via the guide members 3A and 3B with the handle provided on the front surface, disengaged from the guide member, and detached from the apparatus main body 2.

The developing device unit 45 also rotates the handle 49 counterclockwise to return the cam 47 to the home position (horizontal position), locks it with the lock member 48, and then holds the guide member 46 with the handle provided with the unit 45 on the front surface. Similarly, the guide member is pulled out toward the user, and is released from the apparatus main body 1 by releasing the engagement of the guide member.

Next, when the developing unit 45 and the process cartridge 3 are mounted on the apparatus main body 2, the reverse operation may be performed with the front door H opened. That is, the developing unit 45 is inserted and mounted in the depth direction of the apparatus main body 2 via the guide member 46 at a fixed position with the upper housing 1 opened. Next, the process unit 3 is mounted while the developing unit 45 is separated from the image carrier drum 30 by rotating the cam clockwise, and then the developing unit 45 is rotated by rotating the cam 47 counterclockwise. Is returned to the home position, and a predetermined developing gap with respect to the image carrier drum 30 is secured via the abutting member. Next, upper housing 1
Is closed, and is engaged with the apparatus main body 2 by an engaging member (not shown). At the same time, the positions of the image carrier drum 30 and the transfer belt 50 are set. It is in a formable state.

Each of the developing units of the developing unit 45 has an advantage that the openings thereof are directed upward, so that the outflow of the developer, the environmental pollution due to the drop, and the occurrence of color mixing between the toners of the respective colors are not caused. .

As described above, since the process cartridge 3 and the developing unit 45 are provided separately, the process cartridge is light-weight, small-sized, low-cost, and disposable for use as a long-life image carrier drum. It is possible to provide a color printer excellent in structure, economy and image quality.

As shown in FIG. 3, the developing unit 45 is supplied with toner from the toner supply Y hopper 60, M hopper 61, C hopper 62 and BK hopper 63 provided on the back surface thereof, and the development is continued. Developer unit due to the fatigue of
45 are exchanged.

The printer of the present embodiment has a laser writing unit B
In the space beside the process cartridge 3,
Further, the transfer surface of the transfer material is disposed in a portion that straddles both the upper housing 1 and the apparatus main body 2 above the process cartridge 3. Laser scanning by
Further, a color toner image formed by being superimposed on the peripheral surface is transferred to the lower surface of the transfer material.

Thus, in this apparatus, (1) since the paper feed system C including the paper feed cassette and the developing unit 45 are arranged below the image carrier drum, the center of gravity is located below and the structure is stable against mechanical vibration; It is arranged.

(2) In addition, the paper jam of the paper transport system can be easily processed.

Next, using the color printer of FIG. 1, the image formation of this embodiment was performed as follows.

That is, a video signal A composed of Y, M, C, and BK color signals is sequentially output from the image reading device separate from the printer of the present embodiment via the semiconductor laser device 100 for each rotation of the image carrier drum 30. Output to writing system B. First, a Y signal is input to the laser device 100 at the first rotation of the image carrier drum 30, modulates laser light oscillated from the device, and the modulated laser light obtained is a polygon mirror rotated by a drive motor 31. 32, the optical path is bent by the three mirrors 34A, 34B, and 34C through the f-θ lens 33, and the image carrier drum 30 is applied with a charge of 700 V in advance by the charger 35 as charging means. The image was projected on the peripheral surface, and an electrostatic latent image was formed on the image carrier 30. This latent image is subjected to non-contact reversal development by a Y developing device 36 containing a two-component developer composed of a Y toner and a magnetic carrier when a developing bias of a DC component of -600 V and an AC component of 3 KHz and 500 V is applied, and the image bearing member is formed. A Y toner image was formed on the body.

Next, the image carrier drum 30 enters the second rotation in a state where the cleaning device 40 is released, and after being recharged by the charger 35, a laser beam modulated by the next M signal is projected to form an electrostatic latent image. Was formed, and non-contact reversal development was performed by the M developing device 37 to which the same developing bias was applied as described above to form an M toner image on the Y toner image. Similarly, at the third and fourth rotations of the image carrier drum 30, image exposure with laser light modulated by the C signal and the BK signal,
The non-contact reversal development under the same conditions as described above by the C developing device 38 and the BK developing device 39 is repeated, and the Y toner image, the M toner image, the C toner image, and the BK toner image are superimposed on the image carrier in this order. A color toner image was formed.

The color toner image thus obtained was transferred by the paper feed cassette C to the lower surface of the transfer material sent through the paper feed roller 12 and the paper feed guide in the transfer unit.

That is, the color toner image is charged by the pre-transfer charger 9 to facilitate the transfer, and then the transfer belt 50 used as the transfer means rotated from the start of the transfer is brought into contact with the image carrier drum 30 to be supplied. Paper feed roller from paper cassette C
The image was transferred to the transfer material supplied via the roller 12 and the timing roller 13 at the same timing as the image formation.

The transfer belt 50 is stretched between a roller 59 and a roller 60, and is rotated in synchronization with the peripheral speed of the image carrier drum 30 by rotation of the roller 60. It is separated or brought into contact with the image carrier drum 30.

The roller 58 is attached to a lever 57 that can swing about the axis of the roller 60 as a fulcrum, and is held at an upper position indicated by a solid line by an elastic member that biases the lever 57. The transfer belt 50 was moved to a position below the dashed line, that is, a position where the transfer belt 50 was pressed against the peripheral surface of the image carrier drum 30 by the power of a solenoid or the like that operates at the timing shown in FIG. As the transfer belt, for example, a special dielectric belt SDB (trade name) manufactured by Yamauchi Rubber Industries Co., Ltd., which is composed of a conductive substrate and a dielectric layer, was used, and a voltage of +2.0 KV was applied to the transfer belt. In this state, the color toner image on the image carrier 30 was transferred onto the transfer paper. After the transfer, the toner image was heated and fixed by the fixing roller 80 to form a color image, and was discharged face-down to the discharge tray 91 by the discharge roller 90. Next, after transferring the color toner image, the cleaning device 40
Is turned on, the residual toner on the image carrier drum 30 is cleaned, and is ready for the next image formation.

An image forming method for forming a color toner image by superimposing toner images of the respective colors on the image carrier and collectively transferring the color toner images onto transfer paper is disclosed in Japanese Patent Application Laid-Open No.
This method is based on the technique described in Japanese Patent No. 76766, and is advantageous in that the transfer of the color toner image onto transfer paper is performed with high transfer efficiency by using the transfer belt.

In this embodiment, an OP having a life of about 60,000 times of a color image
An image carrier drum 30 made of a C photoreceptor was used. After the image formation was continued up to 60,000 times, the process cartridge 3 was replaced. During this time, the developing unit was inserted and removed every 20,000 times of color unit image formation in consideration of the fatigue of the carrier in the 45 developer.

Color image forming in scraping from the image bearing member drum 30 by the cleaning device 40, the collected waste toner is collected in the conveyed waste toner container 47 by the toner conveying pipe 41 which is laid on the front surface of the apparatus body K ₁ Thus, it is possible to continue image formation for a long time. With the configuration of the color printer as described above, a stable color image can always be obtained for a long period of time.

In the above description, a color printer is taken as an example, but a color copier can be made by combining a color scanner.

〔The invention's effect〕

As is apparent from the above description, according to the color image forming apparatus of the present invention, a stable supply of a color image is made possible by employing an economically disposable process cartridge, and a stable arrangement and apparatus of image forming equipment The effects such as the achievement of compactness are achieved.

[Brief description of the drawings]

1 and 2 are sectional views of the color printer of the embodiment, and FIG. 3 is a perspective view of the color printer. DESCRIPTION OF SYMBOLS 1 ... Upper housing, 2 ... Device main body 3 ... Process cartridge 9 ... Pre-transfer charger, 30 ... Image carrier drum 35 ... Charger, 36, 37, 38, 39 ... Developing device 40 … Cleaning device 41… Toner transport tube 45… Developing unit 47… Waste toner collection container 50… Transfer belt 100… Semiconductor laser device A… Video signal B… Laser writing device C: Paper cassette

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor, Seiko Naganuma 2970, Ishikawacho, Hachioji-shi, Tokyo Konica Corporation (72) Inventor, Masahiko 2970, Ishikawacho, Hachioji-shi, Tokyo Konica Corporation Inspector Hideshi Suzuki (56) References JP-A-63-43170 (JP, A) JP-A-64-101561 (JP, A) JP-A-62-294263 (JP, A) JP-A-62-270967 (JP, A) JP-A-63-259576 (JP, A) JP-A-61-151560 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 15/00 550 G03G 21/16-21 / 18 G03G 15/01

Claims (1)

(57) [Claims] 1. A color image forming apparatus having a charger, a plurality of developing devices, a cleaning device, and a transfer unit on a peripheral edge of an image carrier drum, wherein the transfer unit is a transfer unit using a transfer belt, A process cartridge integrally including a drum, a charger, and a cleaning device is configured to be removably insertable into and removable from the apparatus main body; the plurality of developing devices are arranged below the image carrier drum; When the process cartridge is inserted into and removed from the apparatus main body, the transfer belt is opened upward, and the plurality of developing devices are moved downward as an integrated developing device unit. A color image forming apparatus, wherein the process cartridge is inserted into and removed from the front side of the apparatus main body.