JPH02203358A - Color picture forming device - Google Patents

Abstract

PURPOSE:To increase the degree of freedom when each developing unit is attached to and detached from a main body by providing a means detecting the position and type of attached developing unit and altering a picture forming control mode by an input from the detecting means. CONSTITUTION:The developing units 36 to 38 are added with marks indicating the type of developing unit and identified by the color of contained developer. When each developing unit is loaded in any position of a developing unit loading part, a position mark for each loading position and the type of loaded developing unit are read by readers 70 to 72 as digital signals, which are stored in a RAM 62, etc., via a CPU 60. As copying starts, the CPU reads a picture forming mode and the position and type of developing unit required for executing the picture forming mode from a ROM 61 and the RAM 62, and controls picture formation. Consequently, the degree of freedom in operating the developing unit is expanded, and a stable color copy free of color turbidity can be obtained constantly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color image forming apparatus, and more particularly to a color image forming apparatus in which flexibility in replacing a developing device is ensured and color turbidity is prevented.

[Background of the invention]

As a conventional color image forming apparatus, for example,
As described in Japanese Patent No. 76766, a color toner image is formed on an image carrier by repeating writing in each color with a color scanner using a laser beam and development with a developer containing color toner, and this is transferred to a transfer material. A technique is known in which a corona discharger is used to electrostatically transfer and fix a color image all at once. According to this technique, since the toner images of each color are superimposed on the image carrier, there are advantages such as excellent superposition accuracy.

[Problem that the invention seeks to solve]

In the color image forming apparatus of the present invention, each time an electrostatic latent image is formed on the image carrier, the plurality of developing devices are sequentially operated to repeat development. When the later color toner image is superimposed by the later development on the previous color toner image obtained by the previous development, the toner of the light color toner image gets mixed into the developing device that performs the later development. However, there are problems in that a clear color image cannot be obtained due to color mixing caused by the toner image and scattering of the toner image during image exposure.

Further, when the toner contained in the developer contained in the plurality of developing devices is consumed or the carrier becomes fatigued, the developing device is replaced with a developing device containing new developer, and copying is continued. In addition, in the plurality of developing devices, each developing device is arranged at a predetermined position on the machine body according to the type of developer contained therein (in particular, the color WR of toner), and development is repeated in accordance with that order to produce an image. Formation takes place. This is because if the setting positions of the respective developing devices are bent, the development sequence of color toner will change, and the tone of the resulting color image will change.

Particularly in a color image forming method in which toner images are superimposed on an image carrier, the change in color tone becomes even greater because the potential of the previous toner image influences the potential of the next latent image.

Therefore, when replacing the plurality of developing devices, it is troublesome to check the setting position of each developing device and install it in the machine body.

[Means for solving problems]

(Object of the Invention) An object of the present invention is to reduce color turbidity of a copy image due to color mixing of color toners when forming toner images of each color superimposed on an image carrier, and to prevent the development devices from being restricted in the arrangement order. The purpose of this is to increase the degree of freedom in inserting and removing each developing device into the machine body, thereby making it easier to handle the device as copying continues.

(Structure of the Invention) The above object is to provide a color image forming apparatus in which a plurality of removable developing units for developing a latent image on the image bearing member are disposed at the peripheral edge of the image bearing member. This is achieved by a color image forming apparatus characterized in that it has a detection means for detecting the type and position of a developing device, and changes the image formation control mode based on input from the detection means.

(Specific Structure of the Invention and Its Effects) The color image forming apparatus of the present invention forms a toner image of each color on an image carrier, transfers the same in batch, and fixes it to form a color image. The plurality of developing devices for forming the toner images of each color are replaceable individually or integrally, and there is no restriction on the arrangement order when installing the developing devices in the machine body, and the developing devices can be arbitrarily selected. It has characteristics. Furthermore, as mentioned above, the order in which the developing units are arranged in the machine is arbitrary, but the order in which the toner images of each color are formed for color image formation, that is, the developing sequence, is maintained constant by providing a control means. It is characterized by the fact that it is In other words, even if the arrangement order of each developing device changes, the optimum development sequence is always maintained, thereby preventing fluctuations in image quality and color turbidity and tone deterioration of copied images due to color mixture during development. There is.

By the way, when a plurality of color toner images are formed on the image carrier by multiple rotations of the image carrier drum, the toner of the color toner image formed by the previous developer is transferred to the developer that forms the next color toner image. This causes color mixing and muddying of the copied image. According to the inventor's experimental results, color turbidity due to color mixing occurs when a light color toner image is formed first and a darker color toner image is formed later, regardless of the development method. , color turbidity due to color mixing is not noticeable and does not pose a practical problem. Further, when the toner image on the image carrier is subjected to image exposure, scattering of the toner image is observed. Such image quality deterioration is relatively less noticeable when a light color toner image is formed first than a dark color toner image. Further, the potential of the previous toner image influences the potential of the subsequent latent image.

As described above, when a relatively bright color toner image is formed first and a dark color toner image is formed later, color turbidity and toner image scattering due to color mixing are less noticeable, which is a practical problem. I found out that it will happen.

Therefore, in the color image forming apparatus of the present invention, a Y developing device containing Y (yellow) developer, an M developing device containing M (magenta) developer, and a C developing device containing C (cyan) developer are used. When attaching it to any position on the machine to form a full-color image, use Y-M- as the development sequence.
Preferably, the order is C. In addition, an R developing device containing R (red) developer, a C developing device containing G (green) developer, a B developing device containing B (blue) developer, a BK developing device containing BK developer, etc. When forming a two-color or three-color functional color image, the development sequence is R→B-BK or R-G.
-BK, etc. is preferable.

In the color image forming apparatus of the present invention, a full color copy mode and various functional color modes suitable for the present invention are stored in advance in a ROM, etc., and these modes can be changed by operating keys on the operation panel provided on the top surface of the machine when starting a copy operation. Which copy mode to use is specified via the CPU.

On the other hand, marks such as those shown in Table 1 are provided on the developing device mounting portion of the machine body to indicate the mounting position of the developing device. Further, each developing device is provided with marks such as those shown in Tables 1 to 6 in advance to indicate the type of developing device, which is distinguished by the color of the developer stored therein. When the developing unit is installed at an arbitrary position on the unit, the position mark for each installation position and the mark for each type of the installed developing device are read as digital signals by a reader and stored in a RAM or the like via the CPU.

When the copy starts, the ROM and RA are
The image forming mode and the type, class, and position of the developing device necessary for carrying out the image forming mode are read from M, and image forming is controlled.

(R, G Table 3 BK functional colors) (R Table 4 BK funkun ternary colors) Table 1 (Full color) Table 2 (R, B, BK functional colors) Table 5 (B , BK 7 Ankh/!! Null Color) Table 6 B Functional Color) Next, in the color image forming apparatus of the present invention, an image bearing drum, a plurality of color developing devices, a cleaning device, a charger, etc. It is preferable to integrate the image forming device into a process cartridge that can be inserted into and removed from the machine body. Such a configuration has the advantage of avoiding unnecessary use of the device and ensuring the quality of color copies. In addition, the device is made more compact, making it possible to develop a color popularization machine that has recently been desired in the copying industry. Further, the adoption of a process cartridge has advantages such as ease of jam removal and parts replacement.

〔Example〕

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the embodiments of the present invention are not limited thereto.

(Example 1) Figure 1 shows the main configuration of a color image forming apparatus according to this example, including Y, M, and C full color developing units, OPC
This is a digital color image forming apparatus that incorporates an image bearing drum made of a photoreceptor, a cleaning device, and a process cartridge containing a charger. The developing devices for each color are arranged horizontally in parallel in the developing device mounting portion of the process cartridge, and the order of the parallel arrangement is random, but as a result, from the top, the M developing device (position 1), the Y developing device (Position 2
), and C developing unit (position 3). Full-color copying was performed by a control mechanism to be described later in accordance with an image forming program including a full-color Y-+M-+C development sequence.

The configuration, image forming program, control mechanism, etc. of the color image forming apparatus of this embodiment will be explained below.

In the figure, A is an image reading system, B is a semiconductor laser writing system,
C is an image forming section, D is a paper feeding section, and image formation was performed by the following image forming process.

In the reading system A, 11 is a document table;
1 is illuminated by a halogen lamp 13 attached to a carriage 12 that slides horizontally, and a movable mirror unit 15 has mirrors 16 and 1.
7 is attached to the mirror 14, which also slides in the horizontal direction, and in combination with the mirror 14 attached to the carriage 12, an optical image of the document is guided to the image reading section 22.

The carriage 12 and the movable mirror unit 15 are connected to a stepping motor by wires (both not shown).
and slid in the same direction at speeds of V and 1/2V, respectively. In order to read the document placed on the platen glass II in the image reading section 22, first, the N
The light image of the manuscript was separated into colors.

A Yozu B filter was set, and the light image that passed through the B filter was converted into an electrical signal by a CCD photoelectric conversion device, and further A/D converted to obtain an image signal, which was output to the next image processing section 23. . In this image processing section 23, a Y signal separated by color according to the color of the toner is output, and inputted to the laser writing system unit B, which is an exposure means.

In the laser writing system unit B, a laser beam generated by a semiconductor laser (not shown) is rotated and scanned by a polygon mirror 32 rotated by a drive motor 31, passes through an fθ lens 33, and has an optical path bent by a mirror 34. The circumferential surface of the image carrier drum 30 to which a charge was previously applied by a charger 35 serving as a charging means was scanned.

On the other hand, when scanning is started, the beam is detected by the index sensor, modulation of the beam by the Y signal is started, and the modulated beam is scanned over the circumferential surface of the image carrier drum 30. Therefore, a latent image corresponding to the Y signal was formed on the circumferential surface of the image carrier drum 30 by main scanning by the laser beam and sub-scanning by the rotation of the image carrier drum 30.

This latent image was developed by a developing device 37 loaded with yellow (Y) toner (developing medium) of the developing means, and a toner image was formed on the drum surface. The obtained Y toner image is separated from the circumferential surface of the image carrier drum 30 while being held on the drum surface by a cleaning device 39, which is a cleaning means.
The next copy cycle was performed.

That is, the image carrier drum 30 is charged again by the charger 35, and then the M signal outputted from the image processing section 23 is input to the writing system unit B, and the drum is charged in the same way as in the case of the Y signal described above. The surface was written and a latent image was formed. This latent image was developed by a developing device 361 loaded with magenta (M) toner. The obtained magenta (M) toner image was formed in the presence of the previously formed yellow (Y) toner image.

Reference numeral 38 denotes a developing device containing the toner (C), and a toner image (C) was formed on the drum surface based on the image signal generated by the image processing section. Each of these developing devices 36
, 37 and 38, AC and DC biases were applied to the sleeves, and development was performed without contacting the image carrier drum 30 with a 2fR developer serving as a developing means.

The color image thus formed on the circumferential surface of the image carrier drum 30 is transferred to a recording medium fed from the paper feed section by a paper feed belt and a feed roller 42 at a transfer pole 40 provided as a transfer means. Transferred onto barrel recording paper. The recording paper onto which the toner image has been transferred is separated from the drum surface by a separation pole 43 and sent to the fixing device 4 via a conveyance bell 1-44.
5, and the image was fixed.

On the other hand, the blade 39A of the cleaning device 39 is attached to the image carrier drum 30 from which the recording paper is separated from the drum circumferential surface.
The remaining toner is removed by contact with the drum, and after that, the drum is separated from the peripheral surface of the drum again and prepared for a new color image forming process.

Next, to explain the layout of each of the main components mentioned above, as shown in FIG. .

The main body 2 incorporates an image recording system consisting of the writing system B5, image forming section C1, paper feeding section, etc., and receives data from the image reading system A via a group of flexible cables connected to the housing 1. It is designed to receive color signals.

In the main body portion 2, an image carrier drum 30 is located approximately in the center.
are located and facing the right circumferential surface of each of the developing units 36, 37.
38 were arranged horizontally in that order, while the charger 35 and the cleaning device 39 were arranged on the circumferential surface.

The image carrier drum 30, the charger 35, the developing units 36, 37, 38, and the cleaning device 39 are all housed in the process cartridge 3 and are removably attached to the main body 2 in an integrated state. .

The process cartridge 3, as shown in FIG. The guide member allows for easy removal and installation.

That is, rails 4A are provided on the left and right side edges of the 70 access cartridge 3, and guide rails 4B are provided inside the main body 2 corresponding to the rails 4A, and the rails 4A are slidably engaged with the guide rails 4B. and was attached to the main body 2.

Each of the developing units 36, 37, and 38 had the following configuration.

In this embodiment, the developing devices 36, 37, and 38 all have the same structure and can be installed in any order.
The developing device used in the present invention will be explained with reference to a sectional view of the developing device 37 shown in FIG.

In the figure, 30 is an image carrier drum, 3702 is a housing, 3703 is a developing sleeve, 3704 is a magnet roller 2.3705 is a rigid and magnetic rod-shaped body (cylindrical rod) that regulates the amount of developer, and 3715 is a cylindrical rod. 3
Holder that holds 705 3706 is a cylindrical rod 3705
The cylindrical rod 3705 is a spring member that enables the developer to be conveyed by the pressure between the developing sleeve 3703 and the developing sleeve 3703, and the cylindrical rod 3705 is pressed against the developing sleeve 3703 with a constant load without any developer present. 3707 and 3708 are first and second stirring members, 3709 is a supply roller, 371O is a scraper, and 3711 is a stirring partition plate.

Further, 3721 is a toner box that is incorporated into the housing 3702 and integrated with the developing device, and 3723 is a sponge roller that conveys the toner in the toner box 3.721 to the developing device side. The toner in the toner supply section 3721 is supplied to the developer stirring section by a rotating toner supply roller 3722 and a sponge roller 3723.
.

The toner supplied to the stirring section is thoroughly stirred and mixed with the carrier by a first stirring member 3707 rotating in the direction of the arrow and a second stirring member 3708 rotating in the opposite direction so as to overlap with each other. It is sent as a developer to the developing sleeve 3703 via the supply roller 3709.

The first stirring member 3707 and the second stirring member 3708
is a screw-shaped member with a left-handed helical angle that rotates in mutually opposite arrow directions, and the second stirring member 3708
The toner and carrier are transported to the back side by the thrust of
The stirring partition plate 3 whose upper edge slopes low toward the back of the drawing
711 to the first stirring member 3707, and its thrust transports it to the front side of the drawing, and the toner and carrier mix during this time to form a homogeneous developer that is triboelectrically charged. The developing sleeve 37 is rotated in the direction shown by the supply roller 3709.
03 was attached in a layered manner on the circumferential surface.

In this embodiment, a fixed magnet roller 3704 and a developing sleeve 3 rotating in the direction of the arrow (clockwise) on the outside thereof
This thin developer layer adhered to the circumferential surface of 703 develops the latent image on the image carrier drum 30 rotating in the direction of the arrow toward the development area 3712 at intervals and without contact. It is configured to form a toner image.

During this non-contact development, a developing bias containing an AC component is applied to the developing sleeve 3703 from a power source (not shown), and only the toner in the developer is selectively transferred to the surface of the latent image on the image forming sleeve 3703. attached.

The developer having consumed the toner component has a high carrier ratio, is transported by the developing sleeve 3703, is peeled and collected by the scraper 371O, and is mixed again with the developer having a high toner ratio.

On the other hand, each of the developing devices 36, 37, and 38 has a cartridge 3.
However, it was incorporated so that it could be easily attached and detached using a mounting mechanism as shown in Fig. 3.

The case of the developing device 37 will be explained below.
A pair of upper and lower guide pins 51 each having a compression spring externally fitted thereon are installed between a fixed handle 50A and a holding piece 52, and a movable handle 50B is slidably fitted to each of the guide bins 51. is biased to the right.

The movable handle 50B has a pair of upper and lower boss portions 50C.
A suppression lever 54, which is biased counterclockwise by a torsion spring 53, is pivoted to the lower boss portion 50C.

On the other hand, a guide plate 37A on which the developing unit 37 is mounted is fixed to the cartridge 3, and a "key-shaped" notch 60A is provided at the side end thereof corresponding to the suppressing lever 54.

When the developing device 37 is attached to the cartridge, the pressing lever 54 is pressed against the straight portion 6 of the notch 60A.
It is in a relationship that it is in contact with 1 and is slightly pressed down by the clock,
The developing unit 37 is pressed in the direction of the image carrier drum 30 by the reaction force of the pressing and urging means constructed in this way, and the abutting roller provided coaxially with the developing sleeve 3703 is brought into pressure contact with the drum surface. The configuration is such that the distance (Dsd) between the developing sleeves 37A is maintained at a specified value.

On the other hand, in order to remove the developing device 37 from the cartridge 3, the movable handle 50B is slid to the left against the action of the compression spring so as to grasp the movable handle 50B with respect to the fixed handle 50A, and the suppression lever 54 reaches the slope portion 62A. It returns counterclockwise and in the process brings the protrusion 54A into contact with the movable handle 50B and stops.

Therefore, when the handles 50A and 50B are simultaneously pulled at the position where the boss portion 50C has completely pushed the compression spring, the pressing lever 54 escapes from the opening of the notch 60A and the developing unit 3
7 can be taken out and separated from the cartridge 3.

When installing the developing device 37 into the cartridge, place the front end of the developing device 37 on the guide plate 37A, and hold the fixed handle 50.
When pushed in by A, the pressing lever 54 on the movable handle 50B located at the right end of the guide pin 51 comes into contact with the slope portion 63A on the front side due to the action of the compression spring, and due to the inclination angle, it is pushed together with the movable handle 50B. The guide pin 5
1 Slide the top to the left.

When the pressing lever 54 reaches the opening of the notch 60A and the developing device 37 is further pushed in, the movable handle 50B slides to the right due to the action of the compression spring, and the pressing lever 5
4 is in sliding contact with the slope portion 62AI and reaches the linear portion 61A after being rotated slightly clockwise, thereby obtaining the biased state of the developing device 37 described above. Note that the developing units 36 and 38 are also attached to and detached from the cartridge by a similar attachment mechanism. As explained above, the handle member (50A
, 50B) includes a release/lock mechanism for pushing in and out, and can also be used to hold a small and lightweight developing device, making it more effective in terms of its operability. The position of the handle is not limited to the position of the embodiment, depending on the state when the cartridge is pulled out or the weight balance of the developing device, and it may be provided in the center, or two handles may be provided, one on each side.

Next, as shown in FIG. 1 and FIG.
A developing device 36 (M), a developing device 37 (Y), and a developing device 38 (C) are arranged in this order from the top. On the side surface of the developer mounting portion 53, 2-bit barcodes 73b to 75b shown in Table 7 are provided at the top 1 position, the middle 2 position, and the bottom 3 position. Further, on the side surface of each developing device, Y of the developing device is pre-marked.
3-bit barcode 73a in Table 7 for each type of M and C
~75a was provided. When each developing device is installed in the developing device mounting section 43, a bar code for the position and a bar code for the type of developing device are provided on the outer wall of the mounting section 53 for each developing device mounting position. The read signals of Table 7 are read by the readers 70b-72b and 70a-72a, rol,010'', rlO,100,+.

rll, llO" are stored in the RAM via the CPU 60 in FIG.
It was stored in 62. Note that FIG. 3(b) is an enlarged view of the barcode and the reader.

Table 7 On the other hand, the ROM 61 in Figure 1 stores the full color mode or various funky power modes including the unique development sequence according to the present invention, and a mode designation panel 64 provided on the upper part of the machine. A necessary mode is read out from the ROM 61 by key operation.

In this embodiment, a full-color mode including a Y-M-+C development sequence was specified, and a full-color copy process was performed based on the development position information (read signal in Table 7) in the RAM 62.

According to this embodiment, the use of a process cartridge makes it easy to guarantee the quality of color copies, and it also makes it easier to replace parts of the device and clear jams, etc., which makes the device more compact. In addition, when installing each color developing device in the process cartridge and replacing the developing device due to toner consumption, it is possible to install the developing device in any position regardless of the type of developing device, and the optimum method that does not cause color mixing at the same time as the developing device is installed. Since the process mode is automatically selected, there are advantages such as excellent operability and the ability to stably obtain color copies without muddiness.

(Example 2) FIG. 4 is a sectional view of a color image forming apparatus for explaining this example. is R, B, B
It was designed for K functional color. Therefore, in this embodiment, in the reading system A, the optical systems 12 to 17
The optical image obtained through the . is converted into an electrical signal by a reading device 24 including A.
/D conversion, and two systems of R and C image signals were obtained. These two systems of image signals, R and C, are output to the image processing device 25, where they are separated into three color signals, R, B, and BK.
Each color signal was sequentially outputted to the writing device B in this order to form an image.

Further, the process cartridge 3 was the same as that in Embodiment 1, but the built-in developing devices were a B developing device 56 in the top stage (position 1), an R developing device 57 in the middle stage, and a BK developing device 58 in the bottom stage. Ta.

In this embodiment, bar code marks 73b to 75b1 for displaying the position of the developing device shown in FIG. Barcode marks 73a to 75a for displaying the type of developer provided on the side surface and readers 70 to 72 installed on the outer wall of the developer mounting portion 53
Each data is shown in Table 8.

Table 8 The read signals in Table 8 were stored in the RAM 62 via the CPU 60 as in the first embodiment. Furthermore, R, B, and BK functional color modes are designated by key operations on the operation panel 64. The position information of the RAM 62 and the designated process mode of the ROM 61 are CP
An imaging process including a development sequence without color turbidity, which is a feature of the present invention, was carried out through the U60. The other configuration of the color image forming apparatus of this example was the same as that of Example 1.

In this embodiment as well, the mounting position of each developing device in the developing device mounting portion 53 is arbitrary, and even if the mounting position of the developing device changes when replacing the developing device, the mounting position of the developing device and the type of developing device information representing is stored in RAM etc. via the CPU, and
Imaging was carried out automatically based on the process mode of the present invention that does not produce color turbidity as described in M.

〔Effect of the invention〕

As is clear from the above description, according to the color image forming apparatus of the present invention, the developer can be installed and replaced in the machine at any time without being restricted by the installation position, and moreover, the developer can be installed in any position. Since a color copy without color turbidity is automatically achieved regardless of the color difference, the degree of freedom in operating the developing unit is expanded, and stable color copy is always achieved.

Furthermore, when the color image forming apparatus is configured as a process cartridge that can be inserted into and removed from the machine body as in the embodiment,
The device can be made more compact, making it easier to clear jams and replace parts.

[Brief explanation of the drawing]

1 and 4 are cross-sectional views of a color image forming apparatus according to an embodiment, FIG. 2 is a cross-sectional view of a developing device incorporated into the color image forming apparatus, and FIG. 3 is a cross-sectional view of a developing device incorporated into the color image forming apparatus according to an embodiment. FIG. 2 is a perspective view of a process cartridge. A... Image reading system B... Laser writing system C.
...Image forming section D...Paper feeding section 15...Movable mirror unit 9...Switching filter 22, 24...Reading device 2325...Image processing section 3...Process cartridge 30... Image carrier drums 36, 37, 38, 56, 57, 58...
Developer 77.78.79...Barcode reader 35.
... Charger 39 ... Cleaning device 4
0...Transfer device 45...Fixing device 60...
・CPU 61...ROM62...
RAM

Claims (1)

[Claims] Detection for detecting the type and position of the installed developing device in a color image forming apparatus in which a plurality of removable developing devices for developing the latent image on the image bearing member are arranged around the peripheral edge of the image bearing member. 1. A color image forming apparatus, comprising: means for changing an image forming control mode based on input from the detecting means.