JPH0398061A - Color image forming device - Google Patents

Abstract

PURPOSE:To facilitate processing for jamming and maintenance, to make a device small in size and light in weight and to stably supply a high-quality color image by providing a lower housing provided with an attachable/ detachable process cartridge and an attachable/detachable transfer drum and obtaining a clamshell structural body consisting of an upper housing which can open to the lower housing. CONSTITUTION:The upper housing 2 is provided so that it can open to the lower housing 1 and the process cartridge 3 including an image carrier drum 30, a cleaning device 40 and plural developing devices 36-39 arranged under the drum 30 is mounted in the lower housing 1 so that it can be attached to and detached from the housing 1. Then, the transfer drum 50 is mounted in the upper housing 2 so that it can be attached to and detached from the housing 2. The upper housing 2 including the transfer drum 50, etc., is provided so that it can open to the lower housing 1 including the process cartridge 3, etc., so that the clamshell structure is obtained. Thus, the processing for jamming and the maintenance are facilitated, the device is made small in size and light in weight and the high-quality color image is stably supplied.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a transfer drum, and has a lower housing and an upper housing that is openable to the lower housing, and has a talum shell structure. The present invention also relates to a color image forming apparatus such as a color printer or a color copying machine that employs a process cartridge.

[Conventional technology]

As a conventional color image-forming device using a transfer drum,
For example, there is Japanese Unexamined Patent Publication No. 123257/1983.

In this publication, a document image is read, and a laser beam is modulated using the obtained digital signal to write on an image carrier to form an electrostatic latent image, which is developed using a rotary color developing device. The toner images of each color are sequentially layered, transferred and fixed onto transfer paper wound around a transfer drum to form a color image.

In this device, an image carrier drum, a rotary developing device, a transfer drum, etc. are each independently incorporated into the device.
The equipment is large and complex.

For example, Japanese Patent Application Laid-Open No. 58-72159 discloses a transfer drum type color image forming system having a color process cartridge that integrally incorporates an image bearing drum, a charging device, a plurality of developing devices, a cleaning device, etc. A device has been proposed.

In this case, the image forming equipment is housed in a process cartridge that can be inserted into and removed from the device, and can be replaced depending on the usage limit, making it possible to stabilize the quality of color images and make the device more compact. , weight reduction is realized.

[Problem that the invention seeks to solve]

However, since none of the color image forming apparatuses described in the above-mentioned publications have a divided structure, there are problems such as troublesome parts replacement and jam removal. In addition, in conventional color single-image forming devices that use transfer drums, the problem of inserting and removing the transfer drum from the device is that extra space is required for this purpose, and it is difficult to set the position when installed, which tends to cause color misalignment in the image. It is one of the extremely troublesome and important RMs because it damages other image forming equipment when it is inserted and removed. In particular, this is an important issue in the color image forming apparatus of the present invention, which aims to be small and lightweight.

Furthermore, in particular, in the color image forming apparatus described in the above-mentioned Japanese Patent Application Laid-open No. 57-72159, since a plurality of thin developing devices are provided in a horizontally stacked manner, it is difficult to stir and mix the developer in the developing devices. Frictional charging tends to be insufficient due to
Furthermore, color mixing of toners between adjacent developing units is likely to occur, resulting in a decrease in the quality and resolution of color images. Furthermore, since the transfer means including the transfer drum is disposed below the image bearing drum, the cleaning device, and the plurality of developing devices, it is easily contaminated by toner leakage from the cleaning device and the developing devices, resulting in poor image quality. This may cause negative effects such as a decrease in

[Means for solving problems]

(Objective of the Invention) The object of the present invention is to provide a color system that facilitates maintenance such as parts replacement and jam removal, that is small, lightweight, and compact, and that is capable of stably supplying high-quality color images. The purpose is to provide an image type or device.

(Structure and operation of the invention) The above object has a lower housing and an upper housing that is openable to the lower housing, and the lower housing includes an image carrier drum, a cleaning device, and an upper housing. A process cartridge containing a plurality of developing devices arranged below the drum is removably inserted into the housing, and a transfer drum is inserted into the upper housing. This is achieved by a color image forming device which is characterized by being removably attached.

In the color image forming apparatus of the present invention, a lower casing including a writing device for writing color data onto an image carrier drum, a process cartridge, a paper feeder, etc., and a transfer drum, its peripheral equipment, and a paper ejecting device are provided. The lower casing including the components is openable and has a so-called clamshell structure.

The image forming equipment included in the F1 process cartridge includes, for example, an image carrier drum, a pre-transfer charger, a charging electrode, a cleaning device, a waste toner collecting device, and waste toner scraped off by a cleaning device. The waste toner transport tube includes a waste toner transport pipe incorporating a waste toner transport screw for collecting waste toner into a waste toner collection device, a plurality of developing devices arranged on the lower circumferential surface of the image carrier drum, and the like.

Preferably, the plurality of developing units are integrated by sharing a part of the wall surface of each developing unit to form a developing unit;
These developing devices are filled with yellow (Y), magenta (M), cyan (C), and black (BK) two-component developers consisting of non-magnetic toner and magnetic carrier.

Preferably, a toner replenishing device is attached to each of the developing devices from outside the process cartridge to replenish toner.

By the way, when the upper housing is opened, the process cartridge is pulled upward from the lower housing and taken out of the apparatus and replaced, based on the usage limit of the image forming equipment. Further, when the upper housing is opened, the transfer drum attached to the upper housing is separated from the image carrier drum, and jam processing is performed. At this time, when the transfer drum needs to be replaced due to toner contamination, damage, etc., it is removed from the housing via guide means provided in the upper housing and replaced. Further, the transfer drum may be integrated with a gripper, a charger, a presser, a transfer pole, a separating claw, etc. provided on its periphery to form a unit structure, in which case fatigue and deterioration of each equipment in the unit may be avoided. Depending on the damage, the unit can be inserted/removed or replaced via guide means provided in the upper housing.

In the present invention, as described above, a transfer drum is used as a transfer means, and Y, M, C, BK
Each time the toner image of each color is formed, it is transferred onto a transfer paper fixed to a transfer drum, and the color toner image is formed and fixed on the transfer paper to form a color image. This image forming method does not use a special image forming method as described in, for example, Japanese Patent Application Laid-Open No. 60-76766,
This method has the advantage that images can be formed using a process similar to that of ordinary black-and-white image forming methods. Further, since the outer circumference of the image carrier drum can be a so-called demand type, which is smaller than the length of the transfer paper in the feeding direction, in that case, the image form Fii. 'A material can be made smaller and lighter,
Compactness of process units and equipment is achieved.

The transfer drum is arranged obliquely above the image carrier drum due to the structure of the apparatus. That is, due to the image forming process, the image forming equipment such as a cleaning device, a charging electrode, a writing device, and a plurality of developing devices are arranged biased to the right side and below the image bearing drum, so that the transfer drum is not able to carry the image. It is located diagonally above the body drum and offset to the left. When the degree of deviation of the transfer drum to the left is expressed by the inclination angle θ0 of a plane passing through the nuclear image carrying drum axis and the transfer drum axis with respect to a horizontal plane passing through the image carrying body transfer drum axis, usually lO''≦θ ≦
80', preferably 20°≦θ≦70″.

In the color image forming apparatus, the drum shaft of the image carrier drum is driven by an external power source, and when the upper housing is closed, the transfer drum is also driven by a gear provided on the drum shaft and the image carrier drum shaft. It is rotationally driven by gear engagement with a provided gear.

Similarly, the plurality of developing devices are rotationally driven by engagement between a gear provided on the developing roll shaft of each developing device and a gear on the image carrier drum shaft.

Since the color image forming apparatus of the present invention has the above-mentioned structure, it is easy to replace parts such as the image forming device and the transfer drum, and jam removal is easy, and there is an advantage that a stable supply of color images is possible. .

〔Example〕

Figures 1 to 5 are diagrams for explaining this embodiment.
The figure is a cross-sectional view of the printer of this embodiment when the lid is closed, Figure 2 is a cross-sectional view showing the configuration for inserting and removing the process cartridge in the printer when the lid is open, and Figure 3 is the attachment of the transfer drum unit to the upper housing. An explanatory diagram of the mechanism, FIG. 4 is a diagram showing the arrangement angle of each image forming device with respect to the image carrier drum, and FIG. 5 is a time chart during image forming.

The printer of this embodiment includes an image bearing drum 30, a pre-transfer charger 9, a charging electrode 35, a cleaning device 40, a waste toner collection device 70, a waste toner transport pipe 70a containing a waste toner transport screw 70b, and Y, M , C, and BK developing units 36, 37, 38, and 39 are removably attached to the lower housing 1.

Further, the lower housing l ratio is the process cartridge 3.
In addition to the above, a writing device B for writing color data on the image carrier drum 30, a paper feed device 01, a lower half 8lb of the fixing device, etc. An upper housing 2 including a half 81a and a paper discharge device D is provided so as to be openable upward via a hinge 1a.

When the upper housing 2 is opened from 45'' to 90'', the process cartridge 3 is pulled out upwardly or diagonally upward by gripping the handles 3a and 3b using the space between the upper housing 2 and the lower housing l. It is removed from the equipment and replaced with a new one. The transfer drum unit 4 attached to the upper housing 2 includes a transfer drum 50, a gripper 6l1 which is peripheral equipment thereof, a drive device 62 for the gripper 6l, a transfer pole 63, and a gripper 6l.
A pusher 64 for uniformly adhering the wound transfer paper to the transfer drum 50, a charger 65 for electrostatically adhering the transfer paper to the transfer drum 50, a transfer paper separation claw 66, and a drive for the separation claw 66. A device 67 is included.

As shown in FIG. 2, the transfer drum unit 4 can be separated from the upper housing 2 and pulled out by moving in parallel in the eight directions of arrows after opening the upper housing 2 upward with respect to the lower housing l. It is said to be a structure. Note that FIG. 3 shows a side surface of the transfer drum unit in FIG. 2 in the direction of arrow B.

The transfer drum unit 4 has a rail 200A and a rail 200B having a symmetrical L-shaped cross section on the back side as shown in FIG.
A rail member 200 arranged in parallel is attached and fixed, and on the other hand, the upper housing 2 has a guide member 100 having parallel U-shaped symmetrical guides IOOA and IOOB arranged in parallel on the inner surface of the upper housing 2, corresponding to the rail member 200. It is set up.

Further, a release lever 301 biased counterclockwise by a tension spring 303 is pivotally attached to the same inner surface, and the tip of a book member 300 rotatably attached to one end of the release lever 301 is attached to one end of the release lever 301 as one guide of the guide member lOO. It engages with the hole 100B and its host surface protrudes. The release lever 301 is rotated within a range sandwiched between a pair of stop bins 304 by a knob 302 at the other end.

The transfer drum unit 4 engages the rail member 200 with the guide member 100, slides diagonally downward, is housed in the upper housing 2, abuts the stopper 2A, and the rail member 20
A notch 201 provided in one of the rails 200B of the rail 200B is engaged with the hook member 300 to be supported and locked in a predetermined position.

On the other hand, when the release lever 301 is rotated clockwise using the knob 302, the hook member 300 is attached to the rail member 20.
0 is released, the transfer drum unit 4 can slide diagonally to the upper left, that is, in the direction of arrow A in FIG.
can be separated and removed from the upper housing 2. Note that this work can be made easier if a handle or the like is provided on the top surface of the unit.

Thus, when the transfer drum or its peripheral equipment needs to be replaced due to toner contamination, fatigue deterioration, damage, etc., it can be easily pulled out and replaced.

By the way, when the upper housing 2 including the transfer drum unit 4 is closed with respect to the lower housing l, the engaging metal fitting 87a of the upper housing 2 is engaged with the locking metal fitting 87b of the lower housing l, The position of the transfer drum 50 is set with respect to the image carrier drum 30, and at the same time, the transfer drum shaft 50 is set with respect to the gear attached to the image carrier drum shaft 30a at the back of the apparatus.
The transfer drum is also driven to rotate by meshing the gears attached to the drum shaft 30a and driving the drum shaft 30a to rotate by the power source. Further, as the image carrier drum shaft 30a rotates, the gear of the drum shaft 30a meshes with the gear provided on the developing roll shaft of each developing device, so that the developing roll is also rotationally driven. Each of the developing devices includes toner replenishing devices 36a, 37a, . 38a,
Toner is replenished from 39a and image forming continues. As described above, the waste toner scraped from the image carrier drum 30 by the cleaning device [40] is transported by the waste toner conveying pipe 70a installed on the back surface of the drum 30, and is collected by the waste toner collecting device 70. Ru.

The waste toner transport pipe 70a includes a flexible waste toner transport screw 70 that is rotated by the power system of the lower casing l.
b is built in, and is transported to the waste toner recovery device by the propulsive force generated by its rotation.

By the way, each developing device 36 in the process cartridge 3
, 37, 38, and 39 are integrated by sharing the wall surface of the housing between adjacent developing devices, and are arranged so as to surround the lower surface of the image carrier drum. Further, the developing roll 36a.
37a, 38a. The opening on the side 39a faces upward and is arranged vertically.

In addition, the developing units 36, 37, 38, and 39 are distributed to the left and right with respect to the center line of the image carrier drum, that is, the developing units 36 and 37 are on the right side with respect to the axis of the drum 30. I; The developing units 38 and 39 are arranged at symmetrical positions on the left side, and furthermore, the developing sleeves of the developing units 36 and 37 arranged on the right side are arranged clockwise, and the developing units 38 and 39 are arranged on the left side. The developing sleeves of the containers 38 and 39 are rotated counterclockwise to develop the respective images.

By arranging the developing device group in this manner and further rotating the developing sleeve in the opposite direction, the process cartridge 3 and the entire device are balanced from left to right in terms of weight and power transmission, making them easy to handle. This also prevents harmful vibrations from occurring.

In addition, each developing device 36, 37, 3 placed at a symmetrical position on the left and right.
8.39 can have the same structure, and the toner scraping off from the developing sleeve after the development is completed is extremely efficient due to the action of gravity, so that an appropriate amount of fresh toner is always available. Can supply toner.

Next, using the above-mentioned color printer, the image formation of this example was carried out as follows. The laser beam of the semiconductor laser device 400 was modulated based on the video signal A, and the modulated laser beam was input to the laser writing system unit B.

First, during the first rotation of the image carrier drum 30, a charger 35 applies a uniform charge of -700V to the drum, and then a Y signal, which is the first video signal, causes laser light from the semiconductor laser device It 400 to be applied. was modulated, and the obtained laser light was incident on laser writing unit B.

In unit B, the laser beam is scanned by a polygon mirror 32 rotated at high speed by a motor 3l, and is scanned by a collimating lens 33a, a reflecting mirror 34a . 34b. 3
The laser beam has a diameter of 1 through the 4cSr-θ lens 33b.
00 mm image carrier drum 30 was irradiated, and an electrostatic latent image was formed on the drum.

This electrostatic latent image contains a two-component developer, and the DC component is -
A Y toner image was formed on the image carrier drum 30 by non-contact, reversal development using a Y developing device 36 to which a developing bias of 500 V, AC component of 3 KHz, and IKV was applied. This Y toner image was fed from the paper feed cassette 75 and transferred onto a transfer paper wound and fixed on the transfer drum 50. By the way, the transfer paper is stored in the paper feed cassette 7.
After being sent out from the paper feed roll 76 from the paper feed roll 76, the toner was fed to the transfer drum 50 via a conveyance roll 77 and a timing roll 78 in synchronization with the timing of forming a toner image on the image bearing drum 30.

A gripper 61 of the transfer drum 50 is driven by a drive device 62 to support and fix the leading edge of the transfer paper, and the transfer paper is electrostatically attracted to the transfer drum 50, which has been charged in advance by a charger 65, and is wrapped and conveyed. The presser 64 is used to evenly wrap the transfer paper around the transfer drum 50. The Y toner image is transferred onto the transfer paper conveyed together with the transfer drum 50 by the action of the transfer pole 63.
The transfer paper carrying the toner image is separated by a separating claw 66 and a band N. vessel 65
, with the pusher 64 inactive, it was rotated to receive the next color toner image transfer. Note that the image carrier drum 30
Image forming was performed with the cleaning blade 40a in the "on" state from beginning to end.

After being charged by the charger 35 during the second rotation of the image carrier drum 30 and the transfer drum 50, a laser beam is modulated by the M video signal and is written on the drum 30, and M development is performed in the same manner as before. The M toner image was developed using a device. This M toner image is transferred to overlap the Y toner image on the transfer paper which is wrapped around and fixed to the transfer drum 50 which is rotated in synchronization with the image carrier drum 30 with the separating claw 66 being released.

During the third and fourth rotations of the image carrier drum 30 and the transfer drum 50, the C toner image and the BK toner image coated on the drum 30 are transferred to each other based on the C video signal and the BK video signal. A color toner image was formed by superimposing and transferring the Y toner image and the M toner image on the transfer paper.

The transfer paper onto which the toner image is transferred is transferred from the paper feed cassette 75 to the paper feed roll 76 in accordance with the image formation timing.
The leading edge of the transfer paper is supported and fixed on the transfer drum 50 by the gripper 6l, and as the transfer drum 50 rotates, the transfer paper is wound around the drum 50. Note that the transfer drum 50 has a The transfer paper is electrically charged by the band W device 65 and is evenly wound and fixed by electrostatic adsorption, and even more uniform winding is achieved by the rough pressing device 64.

The transfer paper carrying the toner is separated by the separation claw 66 after the gripper 6l is released, and transferred to the transport roll 80.
The image was conveyed to the fixing roll 81 and fixed to form a color image. The transfer paper after fixing is transferred to a conveyor roll 82.
The paper was discharged to a paper discharge tray 85 via a paper discharge tray 83 and a guide 84.

By the way, in an apparatus that uses the transfer drum 50 to form a color image by a transfer method every time, for example, 1/2 of the transfer drum diameter is used.
It is possible to use a so-called demand type image carrier drum using a small diameter image carrier drum, but in this embodiment, the transfer drum diameter and the image carrier drum diameter are the same diameter, as shown in the timing chart of FIG. Both drums were rotated five times in synchronization to form a color image.

In this example, a transfer paper jam occurs at the periphery of the transfer drum after forming a color image 20,000 times.
In addition, the transfer drum was contaminated with toner and the charger and transfer pole on the periphery of the transfer drum were damaged, so the upper housing 2 was opened and the guide IOOA. The drawer was replaced outside the device via IOOB.

After the upper housing 2 was closed and another 40,000 color images were recorded, the upper housing was opened, the process cartridge 3 was replaced, and the next image was created.

During this period, color images with high resolution and high density were consistently obtained.

Although a color printer has been described in this embodiment, a color copying machine incorporating a color scanner may also be used.

〔Effect of the invention〕

As is clear from the above description, the color image forming apparatus of the present invention has a lower housing having a process cartridge that can be inserted and removed, and a transfer drum that can be inserted and removed. Since the upper casing can be opened to create a talum shell structure, it is easy to remove jams, and it is easy to update necessary equipment for maintenance. Effects such as being able to provide a stable supply of

[Brief explanation of drawings]

1 to 3 are cross-sectional views explaining the configuration of the printer of the embodiment, FIG. 4 is a diagram showing the arrangement of each image forming device with respect to the image bearing drum, and FIG. 5 is an image forming time chart. be. l...Lower housing 2...Upper housing 3...
Process cartridge 4...Transfer drum unit 9...Pre-transfer charger

Claims (1)

[Claims] It has a lower housing and an upper housing that is openable to the lower housing, and the lower housing includes an image carrier drum, a cleaning device, and a plurality of developing devices arranged below the drum. A process cartridge comprising a process cartridge is removably installed in the casing, and a transfer drum is removably installed in the upper casing. Device.