JP2614755B2 - 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 using an electrophotographic method, and more particularly, to a color image forming apparatus that is reduced in size to improve maintenance performance and to enhance jam processing performance. .

[Conventional technology]

In an electrophotographic image forming apparatus that forms a full-color image or a monochrome image, a charger that charges a photosensitive drum,
Image exposure means for exposing an image on the photoconductor drum, a developing device for developing an electrostatic image on the photoconductor drum with toner, a transfer device for transferring a toner image on the photoconductor drum to recording paper, and the like are provided on the photoconductor drum. It is arranged around.

Of these, a developing device in a full-color image electrophotographic image forming apparatus includes three or four developing units that respectively store black (BK) toner for yellow (Y), magenta (M), and cyan (C) toners. During the three rotations of the photosensitive drum, yellow (Y),
For magenta (M) and cyan (C), black (BK) toner images are formed on the photosensitive drum, and the toner images are transferred to recording paper to obtain a full-color image. According to such an image forming method, the color image forming apparatus can be made compact by arranging three or four developing devices in a thin and close arrangement.

Japanese Patent Application Laid-Open No. 61-55661 proposes a color image forming apparatus using such an image forming method, in which a latent image is formed by three lasers corresponding to three developing units, respectively, and a photosensitive drum is developed. The apparatus and the cleaning means are integrated into a unit so that they can be taken out of the apparatus body. Further, in the color image forming apparatus described in JP-A-61-55661, although it contributes to improving the maintainability, the developer tends to be spilled or mixed when the unit is inserted and removed. .

Japanese Patent Application Laid-Open No. 58-72159 discloses an example in which a unit around a photosensitive drum is used in a color image forming apparatus that transfers a toner image of each color to recording paper using a transfer drum.

[Problems to be solved by the invention]

However, in the color image forming apparatus described in JP-A-58-72159, (1) the image forming section extends not only around the photosensitive drum but also to the transfer drum.

(2) It is necessary to maintain the peripheral speed and the gap between the photosensitive drum and the transfer drum with high accuracy.

(3) A release mechanism is required to remove the photosensitive drum.

As described above, in a color image forming apparatus using a transfer drum, not only the mechanism is complicated and expensive as described in (2) and (3), but also a monochrome image forming apparatus which does not require a transfer drum. The image forming means is not concentrated around the photoreceptor and the image forming unit is unitized (process unit)
Was not fully obtained.

The present invention improves the maintainability by integrating the developing unit, the image bearing member, and the cleaning unit, or by using a cartridge configuration in which two of them are integrated and the other is independently insertable and removable. When a scale and a plurality of developing units are unitized and the unit is inserted into and removed from the apparatus main body, especially when the developing unit is inserted and removed, the developer spills out to the outside, or the developer is transferred to another developing unit. It is an object of the present invention to provide a color image forming apparatus which is configured to prevent the recording paper from being mixed, and in which, when a conveyance failure of the conveyed recording paper occurs, the jam processing is facilitated.

Still another object of the present invention is to provide a color image forming apparatus by a process of forming a synthetic toner image such as a color toner image composed of a plurality of color toners on the surface of a photoreceptor drum and collectively transferring the resultant onto a transfer sheet. For compactness, for example, a plurality of developing devices and cleaning means as image forming means are concentrated around the photosensitive drum, and in particular, the developing devices are substantially flattened on one side around the photosensitive drum. It is loaded and arranged as a shape. On the other hand, an object of the present invention is to provide a color image forming apparatus in which an opening direction of an upper housing of a main body is set to a direction excellent in operability because a developing unit side including a plurality of developing devices becomes heavy.

[Means for solving the problem]

An object of the present invention is to provide an apparatus main body including an upper housing and a lower housing, each of which has Y, M, and C developers, and includes a plurality of developing devices including at least three developing devices arranged so as to overlap in a vertical direction. Wherein the upper housing having a rotatable image carrier and a cleaning means is parallel to a rotation axis of the image carrier with respect to the lower housing, and the developing unit is arranged with respect to the rotation axis. And a pressing member for pressing the plurality of developing devices toward the image carrier side is provided in the developing unit, and the device main body is configured to be openable about a shaft disposed near the side wall of the apparatus main body. When the developing unit is opened, the developing unit is separated from the image carrier. When the developing unit is separated from the image carrier, the image carrier and the cleaning unit are integrally formed. The unit is configured to be independently insertable into and removable from the apparatus main body with the sleeve side facing upward, and when forming an image having a plurality of colors, the non-contact development is performed a plurality of times by the plurality of developing units. A color image forming apparatus is characterized in that a color developed image is formed by superimposing a plurality of developed images on the image carrier and is transferred onto a transfer material at a time.

〔Example〕

The color image forming apparatus according to the present invention has a so-called clamshell structure that can be divided into an upper housing and a lower housing, and a process member for forming a color image is unitized and attached to the housing. Prior to the description of the structure, the members related to the process and the outline of the operation will be described. FIG. 1A is a schematic configuration diagram showing a first embodiment of the color image forming apparatus of the present invention.

In the figure, reference numeral 11 denotes a photosensitive drum which is an image carrier having a photoconductor layer such as an organic semiconductor, and 12 a charger which uniformly charges the surface of the photosensitive drum 11 which rotates in the direction of an arrow.

Original placed on platen glass 21 (not shown)
Is read by the image reading device 22, and the image reading device
The image data of the document read at 22 is supplied to the laser exposure device 23 after the image processing. Laser exposure equipment 23
After that, the image light modulated based on the image data of the document is irradiated on the photosensitive drum 11, and the image light forms an electrostatic latent image on the surface of the photosensitive drum 11 uniformly charged by the charger 12. Is done.

The electrostatic latent image is supplied to a first developing device 31Y having a yellow (Y) color developer provided in the developing unit 30, a second developing device 31M having a magenta (M) color developer, and a cyan (C) A) A toner image is formed on the surface of the photosensitive drum 11 by the third developing device 31C having a color developer.

13 is a transfer material supply means, 14 is a transfer device for transferring the toner image formed on the photosensitive drum 11 to the transfer material sent by the supply means 13, and 15 is a photosensitive material for transferring the transfer material onto which the toner image has been transferred. A separator for separating the transfer material from the body drum 11, a transport means 16 for feeding the separated transfer material to a fixing device 17, a discharge tray 18 for receiving the transfer material on which the toner image is fixed by the fixing device 17, and a toner image 19 A pre-cleaning static eliminator 20 for facilitating removal of residual toner on the transferred photosensitive drum 1;
Reference numeral denotes a cleaning device that removes residual toner from the surface of the photosensitive drum 11.

In the color image forming apparatus of the first embodiment,
At least there is a process cartridge 40 including the photosensitive drum 11, the developing unit 30, and the cleaning device 20, and the process cartridge 40 has engaging portions 40a, 40b, 4c provided on the outer wall surface thereof, and a support arm 140a provided on the main body 100 side. , 140b, 140
c and are locked by locking means (not shown). The developing units 31Y, 31M, and 31C in the developing unit 30 form a developer layer thinner than the gap between the developing sleeve and the photosensitive drum 11 on the developing sleeves of the developing units and convey the developing layers.
The development under the non-contact development condition in which the toner flies from the developer layer and adheres to the electrostatic image on the photoconductor drum 11 does not disturb the toner image previously formed on the photoconductor drum 11. Switching between the state in which development is performed and the state in which development is performed and the inoperative state can be easily performed by switching the bias voltage applied to the developing sleeve, and the like. This is preferable because it is not necessary to move the developing device when switching.

Developing units 31Y, 31M, 31 mounted in the developing unit 30
The main body of C has a thin structure, and the developing units have substantially the same structure and are arranged substantially parallel to the photosensitive drum 11, and are compactly unitized. FIG. 2 discloses the developing device 31Y.

In FIG. 2, inside the developing device 31Y, a toner storage device 310, a stirring impeller 311, a stirring impeller 312, a developing sleeve 313, a magnet roll 314, and a toner supply roller 315 are provided.
Is provided. A lid portion 319 is provided on the upper part of the developing device 31Y, and the toner storage device 310 and the stirring impeller 31 inside the lid portion 319 are provided.
1. The scattering of the toner is prevented by covering the stirring impeller 312, the developing sleeve 313, the magnet roll 314, and the toner supply roller 315. The gap between the developing sleeve 313 and the photosensitive drum 11 is maintained by a roller (not shown) provided coaxially with the developing sleeve 313 and abutting on the photosensitive drum 11.

The toner T is stored at the bottom of the toner storage device 310,
The toner T is scooped in the upper left direction in FIG. 2 by the clockwise rotation of the wiper plate 310a. The toner T scooped by the scooping plate 310a is supplied to a toner supply roller.
By the rotation of 315, it is moved to the left in FIG. 2 and supplied to the stirring impeller 311. The stirring impeller 311, the stirring impeller 31
2 and the magnetic carrier and the toner T are stirred, and the stirring impeller 3
The two-component developer D composed of the magnetic carrier and the toner T is attached to the developing sleeve 313 by rotating the counterclockwise direction of 12. Inside the developing sleeve 313, there is a magnet roll 314 having a fixed magnetic pole, and the developing sleeve 313 and the magnet roll 314 constitute a magnetic brush made of the developer D described above.

On the surface of the developing sleeve 313, a thin layer of the developer D is formed by the above-described magnetic brush, and the thickness of the thin layer is set to be smaller than the gap between the developing sleeve 313 and the photosensitive drum 11 by, for example, a magnet. By pressing the developer thin layer forming means 317 such as a magnetic cylindrical bar provided to face the magnetic pole of the roll 314 against the developing sleeve 313, the developer D is shaped into an even thin layer. From the thin layer surface of the developer, the toner T flies toward the electrostatic latent image on the photosensitive drum 11 by an AC bias, and develops the electrostatic latent image formed on the surface of the photosensitive drum 11 to form a toner. Get an image.

During this development, a bias voltage composed of a DC component and an AC component is applied to the developing sleeve 313, and by controlling the bias voltage as described later, the fluctuation of the developing conditions between the developing devices is adjusted. I am trying to do it.

FIG. 3 shows a cross section of the developing unit 30 in which the developing units 31Y, 31M, 31C are mounted. The developing unit 30 constitutes a part of the process cartridge 40. The developing unit 30 is a housing having an opening on the photosensitive drum 11 side, and a guide member 39 including a roller or the like is provided therein, and the developing devices 31C, 31M, and 31Y arranged in parallel are guided by the guide member 39. The developing sleeve 313 is pressed toward the photosensitive drum 11 by an elastic member 32 provided behind the developing device and urged, so that the developing sleeve 313 is maintained at a set distance from the photosensitive drum 11.

In the present embodiment, in addition to the photosensitive drum 11, the developing unit 30, and the cleaning device 20, the process cartridge 40 is provided with a charger 12 and a pre-cleaning static eliminator 19.
When a separation claw is used to separate the transfer material from the photosensitive drum 11, the separation claw is also attached. The motor that is the driving source of the process cartridge 40 is
0, and the process cartridge 40 is
When mounted on a vehicle, power transmission and electrical connection are made by a coupling or the like. Of course, a motor as a drive source may be provided in the process cartridge 40. In this case, the process cartridge 40 may be attached to the main body 100 and may be electrically connected.

When reading an original placed on the platen glass 21 by the image reading device 22, color separation is performed via the filter 9. The filter 9 includes a filter 9R, a filter 9G, and a filter 9 as shown in FIG.
When reading an original, the original is read after passing through any one of the filters 9R, 9G, 9B, and 9ND. The filter 9R, the filter 9G, the filter 9B, and the filter 9ND can be selected by setting the filter 9 in the left-right direction of FIG. 4 (in FIG. 1, the direction perpendicular to the paper).
Then, it is realized by moving by a filter selecting device 22a described later. The filters 9R, 9G, and 9B are filters that pass red light, green light, and blue light, respectively.
Is a neutral filter, which allows all three colors of light to pass.

When the process cartridge 40 is mounted on the main body 100, the detection member 141 (FIG. 3) detects the marker 41 attached to the cartridge 40, and inputs it to the CPU 60 by the control circuit shown in FIG. In the developing unit 30, since the developing devices 31C, 31M, and 31Y containing cyan (C), magenta (M), and yellow (Y) toners are located at predetermined positions, the photosensitive drum 11 For each rotation, yellow (Y), magenta (M), and cyan (C) toner images are sequentially formed on the photosensitive drum 11 by image light emitted from the laser exposure device 4 to the photosensitive drum 11. It is formed.

The toner image thus formed is transferred by a transfer unit 14 onto a recording sheet (not shown) supplied from a sheet feeding device 13. The transferred toner image is heat-fixed by the fixing device 17, and is discharged outside the apparatus after the fixing.

In the development with each toner, the selection of the filter 9 is performed in accordance with the developing device in which the filter 9 operates. That is, in FIG. 5, the determination result of the process cartridge determination circuit 60 from the detection member 141 is supplied to the CPU 61. The CPU 61 receives this determination result and issues a command to the image reading device 22. That is, the filter 9R is used for developing the developing device 31C using cyan (C) toner, the filter 9G is used for developing the developing device 31M using magenta (M) toner, and the developing device 31 using yellow (Y) toner.
When developing Y, a command is issued so that the filter 9B corresponds to the development, and the filter setting is performed by the filter selection circuit 22a. The developing device in the process cartridge 40 is not limited to the three color developers of cyan (C), magenta (M), and yellow (Y), but may include black (BK) or another combination. . Process cartridge 40
By differentiating the marker 41 according to the color of the developer and the combination thereof, a filter setting corresponding to the difference is automatically made, and a color copy is made.

In the color image forming apparatus having the functions described above, the process cartridge 40 of this embodiment is mounted on the upper housing 103 and has a two-part structure that can be opened and closed with respect to the lower housing 101. FIG. 1B shows a state in which the upper housing 102 is opened. In the color image forming apparatus of the present invention, the lower housing 101 and the upper housing 102 are parallel to the axis of the photoconductor drum 11 near one end face on the side where the developing units 31Y, 31M, 31C are located with respect to the photoconductor drum 11. A hinge 103 serving as a center of opening and closing is provided. On the other side opposite to the hinge 103, an opening / closing fitting 104 is provided over the upper housing 102 and the lower housing. The opening / closing fitting 104 is unlocked, and the upper housing 102 is lifted clockwise in the drawing to be opened. Between the lower housing 101 and the upper housing 102, there is a balancing member and a lock member made of a biased spring member or the like (not shown), and opening the upper housing 102 in the clockwise direction in the figure does not require excessive force. The open state is held by the lock member, and the open state is maintained even when the hand is released.

In the present embodiment, the process cartridge 40 including the photosensitive drum 11 and the cleaning device 20 and the developing unit 30 on the left and right sides thereof is attached to the upper housing 102. In the located developing devices 31Y, 31M, and 31c, the developing sleeves 313 corresponding to the openings are all in the upward attitude, and are simultaneously located below the toner storage device 310.

An engaging portion 40a provided on the outer wall surface of the process cartridge 40,
40b and 40c are rail-shaped support arms 140 provided on the upper housing 102.
Since the process cartridge 40 is supported by being engaged with each of the a, 140b, and 140c, the process cartridge 40 can be taken out by pulling out the process cartridge 40 in a vertical direction, that is, a horizontal direction. At this time, since the developing devices 31Y, 31M, and 31C are in the upward position, when the process cartridge 40 is taken out or mounted, the shock may cause the developer to spill or the developer may be mixed into another developing device. Never do. Further, the transfer paper supply unit 13, the transfer unit 14, the separator 15 serving as a separation electrode, the transfer material transporting unit 16, and the fixing device 17 are attached to the lower housing 101, so that the upper housing 102 is opened upward. By doing so, the transfer path of the transfer material is exposed, and when a transfer failure of the transfer paper occurs, the jam processing can be easily performed by directly inserting a hand.

FIGS. 6 (a) and 6 (b) show a second embodiment, which has the same functions as the first embodiment.
In this embodiment, the photosensitive drum 11 serving as an image carrier and the cleaning device 20 are unitized to form a unitary process cartridge 240, which is independent of the developing unit 230 to which the developing units 31Y, 31M, and 31C are attached. It can be inserted and removed. The process cartridge 240 has engaging portions 240a, 240b, 240c provided on the outer wall thereof engaged with rail-shaped support arms 140a, 140b, 140c provided on the upper housing 102, respectively, and locked by locking means (not shown). Have been. Meanwhile, the developer
The developing unit 230 in which 31Y, 31M, and 31C are housed in the same manner as in the first embodiment is mounted on a unit garage 232 that can be inserted and removed in a direction perpendicular to the paper surface. The unit garage 2
32 is rotatable about a rotation support shaft 231 as a rotation center. A spring member biased in a counterclockwise direction may be provided around the rotation shaft 231 as needed.

FIG. 6A is a configuration diagram in an operating state. Since the center of gravity of the unit garage 232 to which the developing unit 230 is mounted is on the left side of the rotation support shaft 231 in the drawing, the unit garage 232 moves counterclockwise. Energized, stopper 1 provided on upper housing 102
The position 40d is in contact with the locking portion 232d provided in the unit garage 232 to regulate the position, and the internal developing units 31Y, 31M, and 31C have the developing positions set for the photosensitive drum 11 by the elastic members 32, respectively. Is pressed.

FIG. 6 (b) shows the opening / closing fitting 104 from the state of FIG. 6 (a).
Is unlocked and the upper housing 102 is opened.
When the upper housing 102 is lifted clockwise, the center of gravity of the unit garage 232 on which the developing unit 230 is mounted moves to the right of the rotation support shaft 231 in the figure, and the unit garage 232 separates from the photosensitive drum 11 and moves clockwise. , And comes into contact with a stopper pin 132 provided on the upper housing 102. In such an open state, the developing devices 31Y, 31M, and 31C are in a more upward posture as compared with the first embodiment, and the developer does not spill or mix. Further, since the photosensitive drum 11 and the developing units 31Y, 31M, 31C are separated from each other, the process cartridge 240 and the developing unit 230
Can be individually inserted and removed in the open state.

FIG. 7 shows a third embodiment, which has the same functions as the first embodiment, but in this embodiment, the photosensitive drum 11 and the developing units 31Y, 31M, 31C are mounted. The developing unit 30 is a unitized process cartridge 340, which can be inserted and removed independently of the cleaning unit 320 having the cleaning device 20. FIG. 7 shows a state where the upper housing 102 is opened. The process cartridge 340 is provided with engaging portions 340a and 340b provided on the outer wall surface thereof, and engages with the rail-shaped support arms 140a and 140b provided on the upper housing 102, respectively, in a state where the upper housing 102 is opened. It can be taken out in the direction perpendicular to the paper (on the front side of the apparatus body). The cleaning unit 320 is a housing having a U-shaped cross section. The pre-cleaning static eliminator 19 and the cleaning device 20 are located inside the cleaning unit 320, and the cleaning unit 320 is mounted on a rotating support shaft 121 projecting in a rod shape from the upper housing 102. In the operating position, the engaging portion 320a provided on the outer wall of the cleaning unit 320 is restricted in position by the stopper 120a provided on the upper housing 120. Holding. Therefore, when the upper housing 102 is opened, the stopper 102a is released, the cleaning unit 320 is rotated counterclockwise, and then the cleaning unit 320 can be taken out in a direction perpendicular to the paper. The cleaning device 20 includes a cleaning unit 320
The lower side and both sides are surrounded by the cleaning unit 320, so that toner is not scattered when the cleaning unit 320 is taken out.

In the present invention, a color image reading device using a color image sensor can be used. Further, the developing device in the electrophotographic image forming apparatus can be constituted by four developing devices which respectively store yellow (Y), magenta (M), cyan (C) and black (BK) toners. In this case, while the photosensitive drum rotates four times, yellow (Y), magenta (M), cyan (C), and black (BK) toner images are formed on the photosensitive member, and the toner images are formed on recording paper. A full-color image is obtained by transfer.

The image data in the present invention is input from an image reading device, but may be image data created by CAD or the like or output from a frame memory storing transferred image data.

〔The invention's effect〕

The color image forming apparatus according to the present invention is a type in which a developing unit is stacked in three or four stages on one side of a photoreceptor drum, and the developing unit is a flat type as shown in the embodiment and develops in one direction. When the toner storage section is provided on the opposite side, the multi-stage type developing device can be arranged substantially in parallel, and can be arranged in one developing unit, and can be compacted together with the photosensitive drum. Process cartridge,
From the viewpoint of facilitating the removal of the process cartridge or the jam processing, it is advantageous to use a so-called clamshell structure device which is divided into two parts. The present invention has such an effect, and by providing the opening / closing shaft on the developing unit side according to the present invention, the developing unit corresponding to the weight portion is close to the opening / closing shaft. Since the opening of the developing device is in the upward position when the developer is taken out, no spillage of the developer and no mixing of the developer into other developing devices occur.

[Brief description of the drawings]

1 (a) and 1 (b) are schematic front views showing a first embodiment of a color image forming apparatus according to the present invention. FIG. 1 (a) is an operating state, and FIG. 1 (b) is an open state. FIG. 2 is a schematic front view showing a developing unit of the color image forming apparatus according to the present invention, FIG. 3 is a schematic sectional view of a developing unit, FIG. 4 is a front view showing a filter used for color separation, FIG. FIG. 5 is a block diagram showing a control circuit for a color image, and FIGS.
(B) is a schematic front view showing the second embodiment, FIG. 6 (a) shows an operating state, FIG. 6 (b) shows an open state, and FIG. 7 is a schematic front view of the third embodiment. The open state is shown in the figure. 9: Filter, 11: Photoconductor drum 12: Charger, 13: Supply means (transfer material) 14: Transfer device, 15: Separator 16: Transport means (transfer material), 17: Fixing device 18 Discharge tray 19 Static eliminator before cleaning 20 Cleaning device 21 Platen glass 22 Image reading device 23 Laser exposure device 30 Developing unit 31Y, M, C Developing devices 40, 240, 340 Process cartridges 40 (240, 340) a, b, c Engaging portion 41 Marking portion 100 Main body 101 Lower housing 102 Upper housing 103 Hinge 104 ... Opening / closing brackets 140a, 140b, 140c ... Support arm 141 ... Detection member 320 ... Cleaning unit

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shizuo Morita 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Co., Ltd. Examiner Kiyoshige Suemasa (56) References JP-A-62-134654 (JP, A) Akira Mikai 60-191053 (JP, U) Actually open 63-125864 (JP, U)

Claims (1)

(57) [Claims] An apparatus main body comprising an upper housing and a lower housing, each of which has Y, M, and C developers, and includes a plurality of developing units each including at least three developing units arranged so as to overlap in a vertical direction. An upper housing having a developing unit having a container, a rotatable image carrier, and a cleaning unit, wherein the upper housing is parallel to the rotation axis of the image carrier with respect to the lower housing, and The developing unit is configured to be openable about a shaft disposed near a side wall of the apparatus main body on a unit side, and a pressing member for pressing the plurality of developing units toward the image carrier is provided in the developing unit; The developing unit is separated from the image carrier in a state where is opened, and the image carrier and the cleaning unit are integrally formed in a state where the developing unit is separated from the image carrier. The image unit is configured to be independently insertable into and removable from the apparatus main body with the sleeve side facing upward, and when forming an image having a plurality of colors, the non-contact development is performed a plurality of times by the plurality of developing units. A color image forming apparatus comprising: forming a color developed image by superimposing a plurality of developed images on the image carrier; and transferring the color developed image onto a transfer material at a time.