JP2748162B2 - Color image forming equipment - Google Patents

Description

The present invention relates to a color printer using a transfer drum, a clamshell structure having an apparatus main body and an upper housing openable to the apparatus main body, and employing a process cartridge. Alternatively, the present invention relates to a color image forming apparatus such as a color copying machine.

[Conventional technology]

As a conventional color image forming apparatus using a transfer drum, there is, for example, JP-A-61-123257. In this publication, an original image is read, a laser beam is modulated by an obtained digital signal and written on an image carrier, an electrostatic latent image is formed, and this is developed with a rotary color developing device. A color image is formed by sequentially superimposing and transferring and fixing each color toner image on transfer paper wound around a transfer drum. In this apparatus, an image carrier drum, a rotary developing device, a transfer drum, and the like are independently incorporated in the apparatus, and the apparatus is large and complicated.

For example, Japanese Patent Application Laid-Open No. 58-72159 discloses a transfer drum type color image forming apparatus having a color process cartridge integrally incorporating an image carrier drum, a charger, a plurality of developing units, a cleaning device, and the like. Proposed.

In this case, since the image forming equipment is assembled in a process cartridge that can be inserted into and removed from the apparatus and can be replaced according to the use limit, the quality of color images can be stabilized, and the apparatus can be reduced in size. , Weight reduction is realized.

[Problems to be solved by the invention]

However, none of the color image forming apparatuses described in the above-mentioned publications has a divided structure, so that there is a problem in that it is troublesome to replace parts or perform jam processing. In particular, replacement of the transfer drum requires an extra space between the transfer drum and the image carrier drum, and it is difficult to align the transfer drum at the time of mounting, resulting in transfer misregistration and color misregistration.

In particular, in the color image forming apparatus described in JP-A-58-72159, since a plurality of developing devices are provided in a thin and horizontally stacked manner, the stirring and mixing of the developer in the developing devices and the triboelectric charging due thereto are performed. Tends to be insufficient, and color mixing of toners between adjacent developing units is apt to occur, and the quality and resolution of a color image deteriorate. Further, since the transfer unit including the transfer drum is disposed below the image carrier drum, the cleaning device, and the plurality of developing devices, the transfer device is easily contaminated by leakage of toner from the cleaning device and the developing device,
There are adverse effects such as a decrease in image quality.

Further, the transfer paper may be jammed particularly around the transfer drum, and it is necessary to separate or return the transfer drum from the image carrier drum each time. At that time, the positioning becomes inaccurate, and the image quality and the resolution are reduced.

Therefore, it is conceivable to incorporate the transfer drum into the cartridge integrally with the image forming equipment. In this case, there is a problem that it is difficult to remove the jam around the transfer drum.

[Means for solving the problem]

(Object of the Invention) An object of the present invention is to adopt a process cartridge including an image forming device and a transfer drum, thereby stably disposing each component device in the apparatus, reducing the size and weight, and facilitating jam processing. Thus, a color image forming apparatus capable of stably supplying a high-quality color image is provided.

(Constitution of the invention and its operation) The object of the present invention is to provide a color image forming apparatus having an image carrier drum, a plurality of developing units, a cleaning device, and a transfer drum. A process cartridge containing a plurality of developing units arranged on the peripheral surface and a transfer drum arranged above the process unit is provided in the apparatus main body so as to be freely inserted into and removed from the apparatus main body, and the housing is provided so as to be openable to the apparatus main body. This is achieved by the jam image forming apparatus in which the transfer drum is separated from the image carrier drum when the upper housing is opened.

In a preferred embodiment of the present invention, the transfer drum is pivoted upward about a hinge provided on a support frame supporting the other shaft of the drum with one shaft thereof as a fulcrum, and is separated from the image carrier drum. This is achieved by a color image forming apparatus.

In the color image forming apparatus of the present invention, the housing can be opened to an apparatus main body having a writing device for writing color data on the image carrier drum and a process cartridge including a plurality of image forming equipment and a transfer drum. And has a so-called clamshell structure.

The plurality of image forming devices housed in the process cartridge include, for example, an image carrier drum, a pre-transfer charger, a band electrode for uniformly charging the image carrier drum, a cleaning device, and waste toner collection. Device
These may be integrated and stored as a unit in the process cartridge.

Further, as the image forming equipment, there are four kinds of developing units filled with yellow (Y), magenta (M), cyan (C), and black (BK) color developing agents. However, it is preferable that the toner replenishing device be integrated and housed as a developing device unit, and that a toner replenishing device is provided for each of the developing devices. It is preferable that the process cartridge is integrally provided as an extension and can be inserted into and removed from the apparatus main body together with the process cartridge. Next, the developer used in each of the developing devices may be a one-component developer containing a magnetic toner as a main component, or a two-component developer composed of a non-magnetic toner and a magnetic carrier. This is a two-component developer with excellent color tone reproduction.

The transfer drum housed in the process cartridge may be housed alone in the cartridge, but preferably, peripheral equipment such as a gripper, a band electrode, a pressing device, and a separator for winding the transfer paper around the transfer drum. May be stored as a unit including

The transfer drum is configured such that one shaft end of the drum can be rotated upward via a hinge provided on a support frame that supports the other shaft end. For this reason, it is easy to perform the jam processing of the transfer paper related to the transfer drum, and it is easy to set the position on the image carrier drum by rotating the transfer drum around the fulcrum and returning to the original position after the jam processing. Is done.

To remove the process cartridge from the apparatus main body, open the upper housing 45 ° to 90 ° upward, then pull up the cartridge vertically upward along the guide provided on the apparatus main body, and install it in the extension of the guide on the way. What is necessary is just to pull out and remove it diagonally upward and horizontally along the inclined part and the horizontal part. The removed process cartridge may be replaced with a new cartridge, or the transfer drum may be pivoted about one end thereof upward at the other end to separate it from the image carrier drum, and then the image carrier drum or The unit including the image carrier tail ram may be pulled out and replaced.

Further, after the upper housing is opened upward, the transfer drum is rotated and separated from the image carrier drum while the process cartridge is mounted, jam processing is performed, and the section of the image carrier drum is performed. Is also good.

Next, the process cartridge is housed in the apparatus main body by the reverse operation to the above, and the upper housing is closed so that an image can be formed.

At the same time as the lid of the upper housing is closed, the image carrier drum shaft is connected to the power source, and the gear provided on the drum shaft engages with the gear provided on the shaft of the transfer drum, the developing roll, etc., and each is rotated and driven to rotate the image. The formation takes place.

Further, the transfer drum is rotated to separate or press against the image carrier drum, and at the same time, the gears connected to them are released or meshed.

Since the color image forming apparatus of the present invention has the above-described configuration, it is possible to stably supply a color image, and it is possible to easily perform jam processing and to easily exchange image forming equipment.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to examples, but embodiments of the present invention are not limited thereto. 1 to 4 are diagrams for explaining the present embodiment.
1 is a cross-sectional view of the printer of this embodiment, FIG. 2 is a cross-sectional view taken along line XX of FIG. 1, FIG. 3 is a layout diagram of peripheral devices with respect to an image carrier drum, and FIG. It is.

In the printer of this embodiment, the image carrier drum 30, the pre-transfer charger 9, the band electrode 35, the cleaning device 40, the waste toner collecting device 70, and the waste toner transport pipe 70a containing the waste toner transport screw 70b are integrated. Y, M, C, and BK developing units integrated with the image carrier unit I and a part of the wall surface
A developing unit II including 36, 37, 38, and 39 is included in the process cartridge 3. Further, the developing device unit
The toner replenishing devices 356, 357, 358, and 359 are integrally connected to II, and can be inserted into and removed from the apparatus main body 1 together with the cartridge 3. Furthermore, the cartridge 3
A transfer drum unit is provided above the image carrier drum.
The unit III includes a transfer drum 50 and a gripper 61, a transfer pole 63, a pressing device 64, a pre-gripper charger 65, a separation claw 66, and the like, which are arranged on the periphery of the drum.

The apparatus main body 1 of the printer includes a writing device B, a paper feeding system C, and a lower half 81b of the fixing device 81 in addition to the process cartridge. An upper housing 2 including a paper discharge system D is provided so as to be openable upward through a hinge 1a (see an open view indicated by a chain line in FIG. 1). When the upper housing 2 is opened upward, the process cartridge 3 is attached to the side wall 3 of the cartridge 3.
Through the vertical portions of the guides 5a and 5b extending from the base along the a and 3b, the handles 4a and 4b are gripped and pulled upward, and thereafter removed out of the apparatus through the inclined portions and the horizontal portions of the guides. You.

Thereafter, as shown in FIG. 2, the unit III including the transfer drum 50 is connected to a hinge 1b provided on the front wall 3c of the cartridge 3.
A vertical groove 3e with the drum shaft 50b provided on the rear wall 3d with the fulcrum as a fulcrum.
The transfer drum 50 and the transfer drum around the transfer drum 50 and the peripheral edge of the transfer drum 30 are removed from the image carrier drum 30 by rotating.

At the same time as the unit II including the transfer drum 50 is separated from the image carrier drum, the gears 50c and 30c mounted on the two drum shafts 50b and 30b and in the meshing state are released from the meshing state, and the transfer drum unit is Separated with II. At this time, in addition to performing the jam processing as described above, the transfer drum unit II is rotated by 90 ° or 120 ° and separated, and then the unit I including the image carrier drum 30 is provided on the front wall 3c by the vertical groove. 3f and the vertical groove 3g provided in the rear wall 3d
A and 30b may be pulled up and replaced while sliding. Next, Y, M, C, and BK developing units are installed in developing unit II.
36, 37, 38, and 39 are integrated with a part of the wall surface being shared and integrated so as to surround the lower surface of the image carrier drum 30 with the opening facing upward. Further, the unit II includes toner replenishing devices 356, 357, 358, and 359 coupled to the respective developing devices. FIGS. 2A and 2B are sectional views of the developing device 37 and the toner replenishing device 357 thereof. I have.

In the figure, reference numeral 373 denotes a developing roller.
The toner is supplied from the toner supply device 357 by the screw conveyor 378. Reference numeral 372 denotes an abutting roller for setting the distance between the image carrier drum 30 and the developing roll 373. The developing roller 373 and the toner supply screw 378 are rotated by 38a and 38b which engage with the gear 30c of the image carrier drum shaft.
The housing of the toner replenishing device 357 is connected to an extension of the developing device housing to be integrated.

In FIG. 2 (a) and FIG. 2 (b), which is a sectional view taken along line AA of FIG. 2, reference numeral 3571 denotes a toner replenishing portion, and 3572 denotes a toner whose bottom portion is removably fitted to an upper opening of the toner replenishing portion. It can be replaced in the replenishment box as the toner is consumed. Reference numeral 3573 denotes a shutter that opens and closes when the toner supply box is replaced. Reference numeral 3574 denotes a toner supply roller.
According to a signal from a toner concentration detection sensor (not shown),
When the electromagnetic clutch MC operates, the gears 38c and 38d mesh with each other, and the toner supply roller 3574 rotates to supply toner.

The replacement of the toner supply box 3572 is performed by opening the front door 6c forward with a hinge 6d provided on the front substrate 6a of the apparatus main body 1 as a fulcrum.

By the way, in the printer of the present embodiment, when a jam occurs at the peripheral edge of the transfer drum or when the image carrier unit needs to be replaced, the transfer drum unit when the upper housing is opened can be removed without removing the process cartridge 3 from the apparatus. It may rotate to perform necessary treatment.

The mounting of the process cartridge 3 to the apparatus main body may be performed by performing the reverse operation at the time of removal. That is, when the upper housing 2 is opened, the side wall 3a of the process cartridge 3 is connected to the substrate guide 5a.
The upper housing 2 is closed by being fed from the obliquely upward direction along the inclined portion of the substrate guide 3a, 3b, and dropped along the vertical portion of the substrate guides 3a and 3b and placed on the bottom substrate 6c.

Next, the image formation of the present embodiment was performed as follows using the color printer having the above configuration.

By the way, in an apparatus for forming a color image by a transfer method every time using a transfer drum, for example, an image forming drum can be formed as a so-called demand type by using an image carrier drum having a small diameter of 1/2 of the transfer drum diameter. In the present embodiment, since the diameter of the image carrier drum is the same as the diameter of the transfer drum, as shown in a timing chart described later,
Synchronously rotated 5 times to form a color image.

First, in the first rotation of the image carrier drum 30, a uniform charging of -700 V is applied to the drum by the charger 35, and then the semiconductor laser device 100 is supplied by the Y signal which is the first video signal of the video signal A. Was modulated, and the obtained laser light was incident on the laser writing unit B. In the unit B, the laser light is scanned by a polygon mirror 32 rotating at a high speed by a motor 31, and a collimator lens 33a, reflection mirrors 34a, 34b, 34c, f-θ lens 33
Irradiated on the image carrier drum 30 having a diameter of 100 mm through b,
An electrostatic latent image was formed on the drum.

This electrostatic latent image is developed in a non-contact, reversal development method by a Y developing device 36 containing a two-component developer, a DC component of -500 V, an AC component of 3 KHz, and a developing bias of 1 KV,
A Y toner image was formed on the image carrier drum 30. This Y
The toner image is fed from the paper feed cassette 75, and is
The image was transferred onto a transfer paper fixed and wound around 50. By the way, the transfer paper is sent out from a paper feed cassette 75 by a paper feed roll 76, and then is transferred to a transfer drum 50 via a transport roll 77 and a timing roll 78 in accordance with a timing of forming a toner image on the image carrier drum 30. Supplied. The gripper 61 of the transfer drum 50 is driven by a driving device 62 to pinch and fix the leading end of the transfer paper, and is electrostatically attracted to the transfer drum 50 charged in advance by a charger 65 and wound and conveyed. The pressing device 64 is for uniformly winding 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 driven by the driving device 62, and the transfer paper carrying the Y toner image is separated from the separation pawl 66, the charger 65, In a state where the pressing device 64 is not operated, the pressing device 64 is rotated to receive the next color toner image. Note that the image formation was performed while the cleaning blade 40a of the image carrier drum 30 was always on.

In the second rotation of the image carrier drum 30 and the transfer drum 50, a uniform charging is applied to the drum 30 by a charger 35, and then a laser beam modulated by an M video signal is written on the drum 30; It was developed by the M developing device in the same manner as the previous time, and an M toner image was formed. The M toner image is transferred in a state where the separation claw 68 is released and is superimposed on the Y toner image on the transfer paper wound and fixed on the transfer drum 50 rotated in synchronization with the image carrier drum 30, and after the transfer. Image carrier drum
The residual toner on the surface 30 was cleaned by the cleaning device 40 and charged by the charger 35. Next, the C toner image and the BK toner image formed on the drum 30 based on the C video signal and the BK video signal are transferred onto the drum 50 on the three rotation and four rotation surfaces of the image carrier drum 30 and the transfer drum 50. The color toner image was formed by being transferred so as to overlap the Y toner image and the M toner image on the paper. The transfer paper carrying this color toner image is released from the gripper 61 and the separation claw 66 is released.
, And conveyed to the fixing roll 82 by the conveying roll 80, and fixed to form a color image. The transfer paper after fixing is discharged to a paper discharge tray 86 via conveyance rolls 83 and 84 and a guide 85.

FIG. 3 shows the relative positions of the respective image forming devices in the respective process units shown in FIGS. 1 and 2 with respect to the image carrier drum 30.

In the figure, the image carrier drum 30 is rotated clockwise, and the rotation phase at the end of cleaning is set as a reference position S, and the positions of the respective devices clockwise in the rotation are shown at angular intervals.

In this case, the process of charging, forming a latent image, forming a toner image, transferring, and cleaning the remaining toner proceeds according to the time chart shown in FIG.
By the end of the five rotations of the image carrier drum 30, the superposition transfer / separation of each color toner image on the transfer drum, cleaning, and the like were completed, and one cycle was completed. In the image carrier unit I, the waste toner removed from the image carrier drum 30 and scraped off by the cleaning device 40 passes through a waste toner transport pipe 70a provided on the back surface of the image carrier unit I, and the waste toner is transferred to the unit. The waste toner is collected by the waste toner collecting device 70 of I.

The waste toner transport pipe 70a has a flexible waste toner conveying screw 70b rotated by a power system of the apparatus main body 1.
The waste toner is conveyed to the waste toner collecting device 70 by the propulsive force accompanying the rotation.

In the present embodiment, a jam occurs due to a poor winding of the transfer paper onto the transfer drum 50 during the image forming process of 10,000 times, and the upper housing 2
Was opened, and the transfer drum unit was opened upward with the hinge 1b as a fulcrum to perform the jam processing. When the image formation was continued 50,000 times after the jam processing, the image carrier drum 30 was replaced in consideration of the fatigue deterioration of the image carrier drum 30. Further, at the time of forming the image 60,000 times, the process cartridge 3 was removed from the apparatus and replaced with a new cartridge in consideration of the fatigue deterioration of the carrier in the developer and the contamination of the transfer drum to prepare for the next image formation.

In spite of the continuation of image formation over a long period as described above, a high-resolution and high-density color image was stably obtained throughout.

In this embodiment, a color printer is described as an example. However, a color copier may be provided with 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, the process cartridge including the image forming apparatus and the transfer drum, the use of the clamshell structure, and the simple transfer of the transfer drum to the image carrier drum By allowing the device to be separated and returned from the device, it is possible to easily carry out jam clearance and maintenance of the device, achieve downsizing of the device, and stably supply a high-quality color image. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the color printer of the embodiment, FIG. 2 (a) is a cross-sectional view taken along line XX of FIG. 1, FIG. 2 (b) is a cross-sectional view taken along line AA of FIG. FIG. 3 is a diagram showing an arrangement angle of each image forming device with respect to the image carrier drum, and FIG. 4 is an image forming time chart. DESCRIPTION OF SYMBOLS 1 ... Device main body 2 ... Upper housing 3 ... Process cartridge 5a, 5b ... Guide, 1a, 1b, 1c ... Hinge 6a, 6b, 6c ... Substrate, 9 ... Pre-transfer charger 30 ... Image carrier drum 32 Polygon mirror 35 Band electrode 36,37,38,39 Developing unit 30c, 38a, 38b, 50c Gear 356,357,358,359 Toner replenishing device 50 Transfer drum 61 … Gripper 70… Waste toner collecting device, 75… Feeding cassette 81… Fixing device 100… Semiconductor laser device A… Video signal B… Laser optical device C… Feeding system D … Paper ejection system

 ──────────────────────────────────────────────────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-2-262678 (JP, A) JP-A-1-172856 (JP, A) JP-A-63-43170 (JP, A) JP-A-63-29150 (JP, U)

Claims (2)

(57) [Claims] 1. A color image forming apparatus having an image carrier drum, a plurality of developing units, a cleaning device, and a transfer drum, wherein the image carrier drum and a plurality of drums arranged on a lower peripheral surface of the drum are provided. A process cartridge containing a developing device and a transfer drum disposed above the developing device is provided in the apparatus main body so as to be detachable therefrom, and an upper housing is provided so as to be openable with respect to the apparatus main body. A color image forming apparatus wherein a transfer drum is separated from the image carrier drum to perform a jam process. 2. The image forming apparatus according to claim 1, wherein the transfer drum is rotated upward about a hinge provided on a support frame for supporting the other shaft of the drum, and is separated from the image carrier drum. 2. The color image forming apparatus according to claim 1, wherein: