JPH02143263A - Color picture forming device - Google Patents

Abstract

PURPOSE:To easily load or remove a process cartridge on or from a color picture forming device and, at the same time, to miniaturize the device itself by using an exchangeable process cartridge housing a developing unit of 1st to 3rd developing devices, image carrier, and cleaning means. CONSTITUTION:Engaging sections 40a-40c provided on the outer wall surface of a process cartridge 40 housing a photosensitive drum 11, developing unit 30, and cleaning device 20 are respectively engaged with supporting arms 140a-140c provided on a main body 100 side and the cartridge 40 is clamped by means of a clamping means. Developing devices 31Y, 31M, and 31C in the developing unit 30 respectively carry developing agent layers formed on their developing sleeves to a thickness thinner than the gap between the developing sleeves and the drum 11 and development is performed under a non-contacted developing condition under which toner scattered from the developing agent layers is adhered to an electrostatic image on the drum 11. Therefore, the process cartridge 40 can be mounted on or removed from the device main body and, at the same time, the device itself can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color image forming apparatus using electrophotography, and more particularly to a color image forming apparatus that is downsized and has improved maintenance performance.

[Conventional technology]

An electrophotographic image forming apparatus that forms a full-color image or a monochrome image includes a charger that charges a photoreceptor drum that is an image carrier, an image exposure unit that exposes an image to the photoreceptor drum,
A developing device that develops the electrostatic image on the photosensitive drum with toner, a transfer device that transfers the toner image on the photosensitive drum onto recording paper, and the like are arranged around the photosensitive drum.

Japanese Unexamined Patent Publication No. 61-55661 discloses three developing devices and three
A color image forming apparatus that forms a full-color toner image on a photoreceptor by forming a latent image and developing it using a book laser, and then transfers the latter toner image to recording paper all at once. It is described that the cleaning means is integrated into a unit and can be taken out from the main body of the apparatus.

The developing devices in this electrophotographic image forming apparatus for full-color images are yellow (Y), magenta (M), and cyan (C).
) toner, and during one rotation of the photoreceptor drum, it produces yellow (Y) toner.
), magenta (M), and cyan (CC) toner images are formed on a photoreceptor drum, and these toner images are transferred to recording paper to obtain a full-color image.

In such a full-color electrophotographic image forming apparatus, especially when trying to form a black image, yellow (Y),
The mixing ratio of each magenta (M) and cyan (C) toner is
Since it is not always in a perfect state, the black image may become reddish or bluish, and the black image may not be clear.

Therefore, in order to obtain a clear black image, yellow (Y),
In addition to magenta (M) and cyan (C), black (BK)
), and black images can be developed with black (BK) toner instead of mixing three colors: yellow (Y), magenta (M), and cyan (C). It is being done.

However, since a developing device containing black (BK) toner in addition to yellow (Y), magenta (M), and cyan (C) toner must be provided, there is a problem in that the apparatus becomes large.

Therefore, a dedicated monochrome development unit that integrates a photoreceptor drum, a corona discharger for uniformly charging the surface of the photoreceptor drum, a developer, and a cleaning device was made removable from the main unit, and in place of that unit, A dedicated color development unit that integrates a photoconductor drum, a corona emitter, a yellow developer, a magenta developer, and a cyan developer arranged in order in the rotational direction of the photoconductor drum, and a cleaning device. A transfer drum type image forming apparatus having a loadable structure is described in Japanese Patent Laid-Open No. 58-72159.

[Problem that the invention seeks to solve]

However, in the color image forming apparatus described in JP-A-58-72159, a transfer drum is used to
Since the configuration is such that each color toner image is transferred to the recording paper, (1) the image forming section III is not only in contact with the area around the photoreceptor drum but also with the transfer drum.

(2) The circumferential speed and gap between the photosensitive drum and the transfer drum must be maintained with high precision.

(3) A release mechanism is required to take out the photoreceptor drum.

As described above, color image forming apparatus 1 using a transfer drum
In this case, not only is the mechanism complicated and expensive as in (2) and (3) above, but also the image forming means is concentrated around the photoreceptor, as in a monochrome image forming apparatus that does not require a transfer drum. The main body device was also enlarged, and the advantages of unitizing the image forming section (process unit) could not be fully obtained.

In addition, in the color image forming apparatus described in the above-mentioned Japanese Patent Application Laid-Open No. 61-55561, the reproducibility of the black Wi image is poor, and the latent image formation is performed using three lasers. In addition to increasing the cost of the device due to parts and positioning, it also required the photosensitive drum to be larger, making it impossible to obtain a compact color image forming device.

Furthermore, replacing each processing section, for example, the developing device, the cleaning means, and the image carrier individually, poses a problem in that handling is troublesome and leads to a decrease in reliability. Furthermore, if such a structure is adopted that allows each processing section to be removed individually, the color image forming apparatus itself must become large in size.

[Means for solving problems]

The present invention solves the above problems, and consists of a first developer having a yellow developer, a second developer having a magenta developer, and a third developer having a cyan developer. a replaceable process cartridge having a developing unit, an image carrier, and a cleaning means; This is achieved by a color image forming apparatus having: a control means for forming a developed image and transferring it onto a transfer material at one time;

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1(a) is a schematic configuration diagram showing an example of a color image forming apparatus of the present invention.

In the figure, 11 is a photosensitive drum having a photoconductor layer such as an organic semiconductor, and 12 is a photosensitive drum 1 rotating in the direction of the arrow.
This is a charger that uniformly charges the surface of 1.

A document placed on the platen glass 21 (not shown)
However, the image data of the document read by the image reading device 22 and read by the image reading/receiving device R22 is supplied to the laser exposure device 23 after being subjected to image processing. The laser exposure device 23 irradiates the photoreceptor drum 11 with image light modulated based on the image data of the document, and this image light creates an electrostatic charge on the surface of the photoreceptor drum H, which is uniformly charged by the charger 12. A latent image is formed.

Each electrostatic latent image is generated by a first developing device 31Y having a yellow (Y) color developer provided in the developing unit 30, a second developing device 311J having a magenta (M) color developer, and a cyan CC). They are each developed by a third developing device 3IC having a color developer to obtain a toner image on the surface of the photosensitive drum 11.

13 is a transfer material supply means; 14 is a transfer device that transfers the toner image formed on the photoreceptor drum 11 onto the transfer material sent by the supply means 13; and 15 is a transfer material onto which the toner image has been transferred, which is exposed to light. a separator for separating from the body drum 11;
Reference numeral 6 denotes a conveying means for sending the separated transfer material to the fixing device I7, 18 a paper discharge plate for receiving the transfer material to which the toner image has been fixed by the fixing device 17, and 19 a remainder on the photoreceptor drum IJ to which the toner image has been transferred. A pre-cleaning static eliminator 20 that facilitates toner removal is a cleaning device that removes residual toner from the surface of the photoreceptor drum +1.

In this color image forming apparatus, a photoreceptor drum 11, a developing unit 30, and a cleaning device 2 are provided.
0, the process cartridge 40 has an engaging portion 40a provided on its outer wall surface.
, 40b, and 40c engage with support arms 140a, 140b, and 140c provided on the main body 100 side, respectively;
It is locked by a locking means (not shown). The developing devices 31Y, 311J, and 31C in the developing unit 30 form a developer layer thinner than the gap between the developing sleeve and the photoreceptor drum II on the developing sleeve of these developing devices, and transport the developer layer, and remove toner from the developer layer. The development is performed under non-contact development conditions in which the toner is caused to fly and adhere to the electrostatic image on the photoreceptor drum 11, so that the toner image previously formed on the photoreceptor drum 11 is developed without being disturbed. This is preferable because switching between the state and the non-operating state can be easily performed by switching the bias voltage applied to the developing sleeve, and there is no need to move the developing device when switching.

A developing device 31Y installed inside the developing unit 30.

The main bodies of 31M and 31C are constructed as shown in FIG. However, FIG. 2 discloses the current device 31Y.

In FIG. 2, 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 inside the developing device 31Y. "Developer 31Y"
The second part is provided with a lid part 319, which includes a toner storage device 310, a stirring impeller 311, a stirring impeller 312,
By covering the developing sleeve 313, magnet roll 314, and toner supply roller 315, toner is prevented from scattering. Note that the developing sleeve 313 and the photosensitive drum 1.1
The gap is maintained by a roller (not shown) f that is provided coaxially with the developing sleeve 313 and contacts the photosensitive drum 11.

Toner T is stored at the bottom of the toner storage device 310,
The toner T is scooped up toward the upper left in FIG. 2 by rotating the wiper plate 310a clockwise.

L・ner T scooped up by the cleaning plate 310a
is moved to the left in FIG. 2 by the rotation of the toner supply roller 315 and is supplied to the stirring impeller 311. The stirring impeller 311 stirs the magnetic carrier and the toner T together with the stirring impeller 312 . The stirring impeller 31.1 and the stirring impeller 312 are rotated in opposite directions, thereby increasing the conveyance distance and sufficiently stirring and mixing the magnetic carrier and toner. The two-component developer consisting of the magnetic carrier and toner T is stirred and mixed and then supplied to the developing sleeve 313.

A magnet roll 3]4 having fixed magnetic poles is disposed inside the developing sleeve 313, and this developing sleeve 3
+3 and the magnet roll 314 form the above-described magnetic plan by the developer.

A thin layer of developer is formed on the surface of the developing sleeve 313 by the above-mentioned magnetic brush. Developer thin layer forming means 3 such as a magnetic cylindrical rod provided opposite to the magnetic pole of the roll 314
17 is pressed against the developing sleeve 313, the developer layer is shaped into an even thin layer. From the surface of the thin layer of developer, the toner T is transferred to the photoreceptor drum 11 by an alternating current bias.
The electrostatic latent image formed on the surface of the photoreceptor drum 11 is developed to obtain a toner image.

During this development, a bias voltage consisting of a direct current component and an alternating current component is applied to the developing sleeve 313, and by controlling the bias voltage as described later, variations in developing conditions between the developing devices are adjusted. I try to do that.

Figure 3(a) shows developing units 31C, 311J, and 31Y inside.
This figure shows a cross section of the developing unit 30 with the
The developing unit 30 constitutes a part of a process cartridge 40. The developing unit 30 includes the photosensitive drum 11
It is a housing with an opening on the side, and a guide member 39 consisting of a roller etc. is provided inside, and the developing units 31C931M, 3
1Y is guided by a guide member 39 and is pressed toward the photosensitive drum 11 by an elastic member 32 provided behind the developing unit and urged, and the developing sleeve 313 is pressed by an abutting roller provided coaxially with the developing sleeve 313. The set distance from the photoreceptor drum 11 is maintained.

In addition to the photosensitive drum 11, the developing unit 30, and the cleaning device 20, the process cartridge 40 is equipped with a charger 12 and a pre-cleaning static eliminator 19 in this embodiment. Further, when a separation pawl is used, this separation pawl is also attached to assist in separating the transfer material from the photoreceptor drum 1.1. A motor that is a driving source for the process cartridge 40 is provided in the main body 100, and when the process cartridge 40 is attached to the main body 1.00, power transmission and electrical connection are made by a coupling or the like. . Of course, a motor serving as a driving source may be provided in the process cartridge 40. In this case, the process cartridge 40 only needs to be electrically connected to the main body 100.

The process cartridge 40 is compatible with the main body 10.
It is inserted and removed from 0. The process cartridge 40 has yellow (Y) and magenta (M) as described above.

Developing device 3 with built-in developers for three cyan (C) colors
In addition to the full-color process cartridge 40 (1) that handles IC, 31M, and 31Y, it also has a built-in color developer such as red, blue, and green (31Rc31B, 31G) and a black (BK) developer. A twin color process cartridge 40 ([) having a developing device 31BK and a monochrome process cartridge 40 (I [I) having only a developing device 318 containing a black (BK) developer.
Seeds are available. FIG. 3(b) shows the developing unit portion of the twin-color process cartridge 40(II), and FIG. 3(C) shows the developing unit portion of the monochrome process cartridge 40(I[[). The structure of the developing device 318 is the same as that of the previously explained developing device 31Y, and will not be described here.
K) Since the amount of toner consumed is large compared to other color toners, a toner replenishing section 321 is provided in the space inside the developing unit to enable toner replenishment to the toner storage device 310. It is said that

Increasing the amount of black (BK) toner stored in this manner has the effect of reducing the frequency of replacing the process cartridge.

Process cartridge 40(1), 40(n), 40
(Ill) is a marker portion 41 (1) corresponding to the detected portion, which is displayed with a protrusion of a different shape and color, respectively;
41 (ff).

41Cm), and when the process cartridge 40 is installed in the main body 100, it is detected by a detection member 141 such as a photocoupler or a microswitch provided in the main body 100, and the process cartridge 40(I) is detected.

It is detected which one of 40(I[) and 40(II[)] is attached. Process cartridge 40 (ff),
In 40 (! [1), the developing device drive and bias voltage are set to be located at the same position as any developing device in the developing unit 31 in the process cartridge 40 (I) so that they can be shared. is preferable.

When reading a document placed on the platen glass 21 with the image reading device eL22, the colors are separated through the filter 9 and then read with a COD, or with a color image sensor without using a filter or the like. etc. are available. An example using a filter will be explained below. As shown in FIG. 4, the filter 9 is a filter 9R1 and a filter 9G.

Consisting of filter 9B and filter 9ND,
When reading the original, use filter 9R and filter 9.
Reading is performed after passing through either the C1 filter 9B or the filter 9ND.

Filter 9R1 Filter 961 Filter 9B,
To select which filter 9ND to select, move the filter 9 in the left and right direction in Figure 4 (in the direction perpendicular to the page in Figure 1).
This is realized by moving the filter selection device 22a, which will be described later. Note that the filters 9R, 9G, and 9B are filters that allow red light, green light, and blue light to pass through, respectively, and the filter 9ND is a neutral filter that allows all three color lights to pass through.

Process cartridge 40 (1) for main body 100
is installed, the detection member) 41 detects this, and the control circuit shown in FIG.
The discrimination signal obtained through the input signal is input. The developing unit 30 contains cyan (C), magenta (M), and yellow (
Developing units 31C and 31M contain toner Y).

31Y are arranged at predetermined positions, each time the photoreceptor drum 11 rotates three times, yellow (Y),
Magenta (M) and cyan (C) toner images are sequentially formed on a latent image portion formed by image light irradiated onto the photoreceptor drum II from the laser exposure device 4.

The toner image formed in this manner is transferred by a transfer device 14 onto recording paper (not shown) supplied from a paper feeding device 13. The transferred toner image is heated and fixed in a fixing device 17, and after being fixed, it is discharged outside the machine.

In developing with each toner, the filter 9 is selected in accordance with the developing device to be operated.

That is, in FIG. 5, the determination result of the process cartridge determination circuit 60 from the detection member 14+ is supplied to the CPU 61. In response to this determination result, the CPU 61 issues a command to the image reading device 22 and the prohibition mode setting circuit 67.

A command is issued to the image reading device 22 as follows.

That is, the filter 9R is used to develop cyan (C) toner in the developer 31C, the filter 9G is used to develop magenta (M) toner in the developer 31M, and the filter 9G is used to develop yellow (Y) toner 631 and Y. issues a command for the filter 9B to respond, and filter settings are made by the filter selection circuit 22a.

Also, the process cartridge 40 (I
II) is attached, the detection member 141 detects this,
A determination signal obtained through the process cartridge determination circuit 60 is input to the CPIJ 61 . Developing unit 30
Since the developing device 318K containing black (BK) toner is provided, a monochrome image is developed. C
When the PU 61 receives a determination signal indicating that the process cartridge 40 (III) is installed, it issues a command to the image reading device 22 to select the green filter 9G or 9ND.

The green filter has spectral characteristics close to human visual perception and can be used in place of filter 9ND. In this case, it is not necessary to provide the filter 9ND.

Similarly, process cartridge 40 (
When [) is attached, the detection member 141 detects this and C
A determination signal obtained through the process cartridge determination circuit 60 is input to the PU 61 . The developing unit 30 includes, for example, a developing device 31R containing red (R) toner and a developing device 318K containing black (BK) toner. Developing is done. Developing device 31 using red (R) toner
When developing R or using black (BK) toner in the developing device 318, filter 9G or filter 9 is used.
The filter selection circuit 22 issues a command to select an ND.
Filter settings are made according to a.

When a process cartridge is set in the prohibition mode setting circuit 67, depending on the type of the cartridge, in the prohibition mode among the image forming modes described below, the image reading device 22, the photoconductor if laser A setting signal is issued to prevent devices such as the exposure device 23 and the developing device from operating.

(a) When Process Car 1-Ridge 40 (I) is installed Color mode (Y, M, C) Available Semi color mode (R, BK) Not available Single color mode (B, G, R) Available single color mode (Y, M, C) Available single color mode (B) Available (b) Color mode (Y, M, C) available when process cartridge 40(n) is installed Not available in semi-color mode (R, BK) Available in single color mode (B, G, R) Available in single color mode (Y, LC) Not available in single color mode (BK) Available (C) Process cartridge 40 (! II) is installed: Color mode (Y, M, C) Unusable semi-color mode (CR, BK) Unusable single color mode (B, G, R) Unusable single color mode (Y, M, C) ) Cannot be used in single color mode (BK) Can be used in color mode (
Y, M, C) are the developing device 31G, the developing device 31M,
This is a mode in which a color toner image is formed using developer unit 3 ], Y, and monochromatic color mode (B, G, R
, ) means that the developing device 31C1 is the developing device 31 for the same latent image.
A mode in which toners of any two colors are superimposed to form a single color (M, developing device 31Y), or a developing device having the above specific color toner (B, G, R), for example, the process cartridge 40 (II) If there is a developing device 31R, this is a mode in which a single color is formed by using that developing device. In addition, in the monochromatic color mode (BK), for the same latent image, developer 31C1 developer 31M, developer 31Y
This refers to both the case where a monochromatic color (black) is formed by overlapping three toner colors, and the case where a monochromatic color (black) is formed independently using the developing device 31BK.

Also, semi-color mode (R, BK) is the developing device 31R.
This is a semi-color mode in which a toner image produced by the developer @31BK is superimposed on a black (BK) toner image produced by the developer@31BK.

Further, the monochromatic color mode (Y 2 , M 2 , C) refers to a mode in which a monochromatic color is formed using toner of any one color of the developing device 31G, the developing device 31M, and the developing device 31Y. The developing bias is controlled by the developing bias control circuit (FIG. 5) 1 in accordance with the image forming mode.

The color image forming apparatus according to the present embodiment described above has a structure in the form of a Talam shell, and FIG. It shows what was done.

The lower body lot and the upper body 102 have a hinge 103 at one end that serves as the center for opening and closing the upper body +02, and an opening/closing fitting 104 at the other end, and the lids are opened by closing the opening/closing fitting 104. There is a balancing member and a locking member (not shown) between the lower part 101 and the upper part 102 of the main body.
The lid of the upper part 102 of the main body can be easily opened in the clockwise direction in the figure, and this state can be maintained. When the lid is open, the recording paper conveyance path is exposed, and the process cartridge 40 is attached to the upper part 102 of the main body, and can be taken out by pulling it out toward the front in the drawing as described above. Of course, it can also be configured to be taken out at the bottom in the figure.

Although filter switching control based on mode settings has been described above, process control can also be switched at the same time. In a mode that forms an image consisting of a two-color image depending on the mode setting, the photoreceptor drum rotates twice, during which it is charged and
After the process of image exposure and development is performed for each rotation, the process is controlled so that the image is transferred to the recording paper in the second rotation, and the surface of the photoreceptor after the transfer is cleaned. In addition, in a mode that forms an image consisting of a single color image depending on the mode setting, charging, image exposure, and development are performed during one rotation of the photoreceptor drum, and then the image is transferred to the recording paper, and the photoreceptor drum that has completed the transfer is transferred to the recording paper. Control is provided to ensure that the surface is cleaned.

〔Effect of the invention〕

A color image forming apparatus according to the present invention includes a photosensitive drum;
Process cartridges containing three-color developing devices can be easily attached to and removed from the main body, and process cartridges containing developing devices using black toner can also be interchangeably attached to and removed from the main body. Since the cartridge signal is transmitted, switching between the color copy mode and the black copy mode can be easily performed. Furthermore, since the process cartridges can be easily exchanged, when the developer is consumed or the photoreceptor becomes fatigued, it is possible to cope with the situation by replacing the process cartridges.

Further, in the present invention, since a transfer drum is not used, the process cartridge can be easily attached and detached, and the apparatus is also compact and has the advantage of being low in cost. Furthermore, since the color image forming apparatus according to the present invention forms multicolor images on the photoreceptor drum without using a transfer drum,
It also has the effect of having little color shift and high reliability.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are schematic front views showing an embodiment of a color image forming apparatus according to the present invention, with FIG. 1(a) in a closed state and FIG. 1(b) in an open state. shows. FIG. 2 is a schematic front view showing a developing device of a color image forming apparatus according to the present invention, and FIGS. 3(a), (b), and (c) are process cartridges (1), (n), (I[I) 4 is a front view showing a filter used for color separation in the color image forming apparatus shown in FIG. 1, and FIG. 5 is a block diagram showing a control circuit of the color image forming apparatus shown in FIG. 1. It is a diagram. 9... Filter 1.1... Photosensitive drum 13... Supply means (transfer material) 15... Separator 17... Fixing device 19... Pre-cleaning static eliminator 20... Cleaning device 22... Image @ reading device 30... Developing unit 31M... Second developing device 318K... Black developing device 40... Process carts 40a, 40b, 40c... Engaging portion 41 (I) , old (ff), 41 (Iff)-i identification section 10...image forming unit 12...charger 14...transfer device 16...conveyance means 18...sheet discharge tray (transfer material ) 21...Platen glass 23...Laser exposure device 31Y...First developer 31C...Third developer ridge 100...Main body 102...Main body upper part 104...Opening/closing fitting 140a, 140b, I40cm support arm 101...
・Bottom part 103...Hinge 141...Detection member Fig. 2

Claims (1)

[Scope of Claims] A developing unit consisting of a first developing device having a yellow color developer, a second developing device having a magenta color developer, and a third developing device having a cyan color developer, and an image carrier. and a cleaning means; forming a color developed image in which developed images of three colors are superimposed on the image carrier by sequentially using the first to third developing devices;
A color image forming apparatus comprising: a control means for transferring onto a transfer material at one time;