JP2750901B2 - Color image forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is provided with a plurality of developing devices that contain colored toners of different colors, and by selectively operating these developing devices on an image forming body. The present invention relates to a color image forming apparatus that outputs a monocolor print of a desired color, or a multicolor print or a full color print of two or three colors.

[Prior art] The above-described image forming apparatus has been put into practical use as an electrophotographic color copying machine. In recent years, in particular, in addition to an analog copying machine, it can be used as an output printer of an electronic filing system or a CAD system. Digital copiers have been put to practical use. Conventionally, as a developing device of such an image forming apparatus, (1) colored toners of different colors (for example, yellow, magenta, cyan, and black) along a drum-shaped or belt-shaped image forming body that carries a latent image; Are arranged in parallel, only the developing device of the desired color is located at the working position close to the image forming body, and the other developing devices are retracted to the non-working position retracted from the image forming body. The configuration is known, or (2) the developing device containing the four differently colored toners is provided on four sides in the circumferential direction of the rotating body, and the rotating body is intermittently rotated in one direction at the time of exposure. There is known a turret type configuration in which a developing device corresponding to an exposure color is caused to face an image forming body.

[Problem to be Solved by the Invention] In such a conventional apparatus, in the former configuration, while one selected developing unit is used, another developing unit is pulled away from the image forming body. Therefore, there is a problem that a large space for arranging the developing device must be provided. Further, a mechanism for preventing toner particles scattered due to rotation of the magnetic brush or the like from being mixed into the adjacent developing device of another color, such as a suction duct, must be separately provided.

On the other hand, the latter configuration has a problem in replenishing toner to each developing device. That is, conventionally, the toner replenishing device is arranged at a position independent of the rotating body, and the toner replenishing device is provided with a toner replenishing device for each color via a tube or the like at a predetermined position close to the shaft end of the rotating body from the toner tank of each color. The supply port is extended. On the other hand, the shaft of the rotating body is hollow, and a supply port for each color that communicates with each developing device through the hollow section is provided at the shaft end, and the supply port of the same color is provided. The toner can be replenished only when the toner is replenished with the replenishing port. As described above, in the conventional configuration, replenishment of toner cannot be performed at an arbitrary position, and the rotating body is rotated before the replenishment so that the replenishing port of the developing device of the color is positioned at the replenishing port of the same color. Must be efficient.

Further, although the space for the arrangement of the developing device can be reduced, even when it is not necessary to use all the developing units as in the case of performing two-color or three-color printing, the rotating body is changed from yellow to black. , The operation of intermittently rotating in one direction so as to sequentially perform the development steps up to and stopping in the order of arrangement for each development unit is repeated, which is not time efficient.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and can reduce a space for disposing a developing device, facilitate toner replenishment, and have good time efficiency for switching a developing device. It is an object to provide an image forming apparatus in a simple form.

Means for Solving the Problems To solve the above problems, a color image forming apparatus according to the present invention develops a plurality of developing devices accommodating developers of different colors by arranging them adjacently in a fan shape when viewed from the side. The developing unit is configured to be rotatable at the base so that one of the developing units can be stopped at the developing position of the photosensitive drum, and is arranged independently of the developing unit. The toner tank of each color and each developing device of the toner replenishing device are connected directly by a flexible tube, so that toner can be supplied regardless of the position of the developing device.

[Operation] When an image input signal for specifying a color to be printed is input as an output of, for example, an electronic filing system or a CAD system, an appropriate control drive unit rotates the developing unit by a predetermined angle. Then, the developing units of 1 to 4 colors to be printed are successively carried to the developing operation position on the image forming body and stopped, and are applied to the surface of the image forming body, so that the desired color mono-color, multi-color or full-color printing is performed. To form When the toner concentration of the developer in the developing device of any color falls below a predetermined range, the toner supply device operates to supply the toner of the color into the developing device via the flexible tube. At this time, toner is supplied regardless of the position of the developing device by arranging the developing device in a fan shape and directly connecting the original device and the toner replenishing device with a flexible tube.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a drum-shaped image forming body provided with a photoconductor such as Se capable of forming an electrostatic latent image on an outer peripheral surface,
When activated, it rotates in the direction indicated by arrow A. Around the image forming body 1, a charging device 2, an image exposure device 3, a developing device 4, a transfer device 6, a cleaning device 7, and an erase lamp 8 are sequentially arranged. The image forming body 1 is uniformly charged by a charging device 2 to a specific polarity, for example, a positive polarity when a photoconductor such as Se is used, and then an image signal corresponding to a first color is formed by an exposure device 3. To form a latent image. This latent image is developed by a developing device containing a color toner of a color corresponding to the image signal to form a first color toner image. The toner image is transferred onto an appropriate transfer material P by the transfer device 6, and the surface of the image forming body after the transfer is cleaned by the cleaning device 7, and is prepared for the next image formation by the action of the erase lamp 8. Then the first
A colored toner image of a different color is formed in a similar process based on an image signal of a second color different from the first color, and this toner image is formed of a transfer material P carrying the toner image of the first color.
A two-color image is formed superimposed on the top. In three-color or full-color printing, this process is repeated for the third and fourth colors. Although not shown, in order to accurately perform the registration (registration) of the toner on the transfer material P, a transfer material is applied to the peripheral surface of the transfer drum as described in Japanese Patent Publication No. 59-37505. Means are provided for firmly clamping and circulating the transfer material at a timing exactly coincident with the movement of the image forming body. Instead of superimposing the toner images of each color on the transfer material as described above, the toner images of each color are sequentially superimposed on the image forming body (that is, the toner images are not transferred to the transfer material every development of each color). A configuration in which an image is finally transferred onto a transfer material may be used. The transfer material carrying the superimposed final color image is conveyed to a heat fixing device (not shown, a pressure fixing device depending on the toner), where the toner image is fixed to form a color print.

The exposure device 3 is preferably a laser beam scanner that exposes and scans a color image in a digital dot form for each color based on a digital image signal input from an electronic filing system or a CAD system, but is similar to a general analog color copying machine. A configuration in which slit exposure is filtered by a filter for each color to perform exposure may be employed. still,
In the former case, the digital image signal is read by a known color separation means and a photoelectric conversion element such as a CCD instead of a digital output device such as a CAD system, and the color image information of the analog original is read for each color, and converted into an electric signal. It can also be obtained by conversion.

The developing device 4 is provided with a plurality of developing devices that store different color toners. In this example, the developing devices 10, 20, 30, and 40 that store the yellow, magenta, cyan, and black color toners are fans. The developing unit 100 is arranged adjacent to the shape. The developing device unit 100 has a pair of parallel outer frames 51 (only one is shown), and the developing devices 10, 20, 30, and 40 are substantially angularly spaced between the outer frames along the outer peripheral side thereof. It is provided at intervals. The developing device unit 100 is provided so as to be able to reciprocate in an angular direction about the base 52 thereof, and a selected one of the plurality of developing devices can be stopped at a position where a developing action to the image forming body 1 is performed. It is configured as follows. The developing unit 100 is reciprocated by a suitable motor via a gear device or a crank mechanism. The motor is preferably an instantaneous braking motor that can rotate forward and reverse, but is not limited to this. For example, a constant speed motor that rotates in one direction is used, and an appropriate clutch is arranged in a drive transmission unit to turn the clutch on and off. Thus, the connection and disconnection of the drive to the developing unit may be performed. In the example of FIG. 1, although schematically shown, a crank having one end pivotally mounted on the outer peripheral side of a disk 53 rotated by an instantaneous braking motor that rotates in one direction (not shown).
By driving the other end of 54 to the outer frame 51 of the developing unit 100, the driving of the motor is given to the developing unit 100. Accordingly, the movement of the selected developing device to the developing operation position can be controlled by the biasing time of the motor. The operation of the developing unit will be described later. The turning range of the developing unit is sufficient as long as the standby portion 80 and the endmost developing unit 40, which will be described later, can be located with respect to the position where the developing operation on the image forming body is performed.

Each of the developing units 10, 20, 30 and 40 has the same structure except for the color of the color toner contained therein.
The drawing shows the developing device 10. The developing device 10 has a casing 12 with an opening at the front, and a magnetic sleeve 11 is provided at this opening so as to be rotatable in the direction of arrow B. The magnetic sleeve 11 extends parallel to the image forming body 1,
The magnet assembly 13 is disposed inside the magnet assembly. A developer formed by mixing a yellow colored toner and a magnetic carrier is contained in the casing 12, and is adhered onto the sleeve 11 by the magnetic force of the magnet assembly 13 and transported. Reference numeral 14 denotes a scraper for scraping the developing material on the sleeve 11, and reference numeral
Reference numerals 15 and 16 denote screws for transporting the developer in the directions perpendicular to the plane of the paper, respectively, and mix the colored toner and the magnetic carrier. The edge of the opening of the casing 12 is relatively close to the surface of the magnetic sleeve 11, thereby preventing the developer from spilling out of the gap therebetween. At the rear of the casing 12, a cylindrical connecting portion 17 having a supply port 17a for supplying colored toner into the casing is formed, and one end of a flexible tube 18 is connected to this connecting portion 17. I have. The other end of the tube 18, as shown in FIG.
The toner supply device 60 is arranged independently of the developing unit 100 and is connected to a toner tank 61 for storing yellow toner. In the tube 18, a flexible transfer coil 19 is provided continuously from the toner tank 61 to the supply port 17a. When the toner concentration detector disposed in the developing device 10 detects that the toner concentration of the developer has dropped below a predetermined appropriate range, the transport coil 19 is rotated by an operation of an appropriate driving device, and the toner tank 61 is rotated. Is supplied into the casing 12.

The above configuration is the same for the developing units 20, 30, and 40. As shown schematically in FIG. 1, the developing unit 20 stores the magenta toner in a toner tank 62, and the developing unit 30 stores the cyan toner. The developing device 40 is connected to a toner tank 63 for storing black toner by tubes 28, 38 and 48, respectively.

The sleeves 11, 21, 31 and 41 of each developing device are arranged such that when they are located at the developing action position X on the image forming body 1, the gap with the image forming body 1 is the same in any developing device. Is set.

The driving of each developing unit is performed by a common driving motor 70 in this example. As shown schematically in FIG. 1, the drive of the drive motor 70 is driven by a chain 71, a sprocket 72, a chain
Power is transmitted by 73 to the drive gears of the electromagnetic clutches 73, 74, 75 and 76 for each developer. Electromagnetic clutch 73,
The driven gears of 74, 75 and 76 are developer units 10, 20,
The drive parts 30 and 40 are connected to a magnetic sleeve, a screw or the like. The electromagnetic clutches 73, 74, 75 and 76 are energized when the corresponding developing device is located at the developing operation position X to operate the developing device, and deactivated when the corresponding developing device is at any other position to deactivate the developing device. Keep in state.

A standby portion 80 is provided at a position deviated downward from the developing device 10 of the developing device unit 100, and the standby portion 80 is configured to be located at the developing operation position during non-printing operation, that is, during standby. The standby portion 80 is not limited to the illustrated position, and may be, for example, a position deviated downward from the outer frame 51.

A click mechanism 90 is provided on the outer frame 51 so that each developing unit can be stopped at an accurate position at the developing operation position X.
The click mechanism 90 has a receiving plate 91 fixed to the outer frame 51. The receiving plate 91 extends continuously in the circumferential direction of the developing unit 100, and has concave portions 92 to 96 formed at substantially equal intervals. On the other hand, a positioning roller 97 that is rotatable about the axis is provided so as to be movable in such a manner as to come in contact with and separate from the surface of the receiving plate 91, and is provided by a suitable spring means 98 in a direction of pressing the surface of the receiving plate. Being energized. Roller 97 has a receiving plate at that position
A part of the peripheral surface is immersed in the 91 recess when it is located.
This immersion has a negligible braking effect when the developing unit 100 is being driven, but is sufficient to prevent overrun due to its inertia when the driving of the developing unit 100 is deactivated. Function. As described above, each of the concave portions 92, 93, 94, 95, and 96 is provided with the standby portion 80, the developing devices 10, 20, 3 when the roller 97 is immersed therein.
0 and 40 are accurately positioned at the developing operation position X.

Each of the developing units 10 to 40 and the standby portion 8 of the developing unit 100
In order to detect that 0 is located at the developing operation position X,
Optical or mechanical position detection means are provided,
A predetermined signal is sent to the drive control unit when each developing unit or the standby unit is located at the developing operation position, and the control unit responds accordingly when the developing unit relates to a color designated for printing. Deactivates the driving of the developing unit 100.

Next, the operation of the developing unit 100 will be described with reference to FIGS.

When an image input signal designating image information to be printed and color information output from an electronic filing system, a CAD system, an image scanner, or the like is sent to the page memory controller 200 in the image forming apparatus, the controller 200 , A corresponding one of a plurality of memory sets stored in advance is called, and the memory set is sent to the control unit 300. In accordance with the memory set signal, the control unit 300 moves the developing units 10, 20, 30, and 40 to the position where the image forming body is to be developed in the order according to the color information. FIG. 4 shows a case where the developing device is arranged in the standby portion 80 from yellow, magenta,
The correspondence between the memory sets stored in the page memory controller 200 and the order of use of the developing units (developing order) in the case of arrangement in the order of cyan and black is shown. For example, when the color information indicates all colors (full color), the memory set 1 is called up, and the developing unit 100 is controlled by the control unit 300 in accordance with the No. 1 pattern of the developer drive order, ie, on the side closer to the standby portion 80, ie, yellow. , Magenta, cyan, and black developing units in this order so as to act on the image forming body. The developing unit 100 whose standby portion 80 faces the developing position X moves clockwise as viewed in FIG. 1 through the crank 54 by the urging of the brake motor, and the yellow developing device 10 When the motor is located at the developing operation position X, the motor is deenergized, and the positioning roller 97 enters into the concave portion 93 of the receiving plate 90 and stops at an accurate position. Around this time, the electromagnetic clutch 73 is energized, and the sleeve 11 rotates to apply yellow toner to the image forming body. On the other hand, a latent image is formed on the image forming body in accordance with image information (page memory) corresponding to yellow, and the latent image is developed by the developing device 10 to form a yellow toner image. After the formation of the yellow image, the brake motor is re-energized, and the magenta developing device 20 of the developing device unit 100 moves so as to be located at the developing operation position X. At this time, the electromagnetic clutch 73 of the yellow developing device 10 is deenergized and the sleeve 11 stops. In the developing device 20 stopped at the developing operation position X, the sleeve 21 is rotated by the bias of the electromagnetic clutch, and the latent image on the image forming body formed corresponding to magenta is developed to form a magenta image. Similar movement and operation are performed for the cyan and black developing units, and toner images of the respective colors are formed.
This toner image is superimposed on the transfer material as described above, or is superimposed on the image forming body to form a full-color image. The motor 70 for driving the developing device is energized at an appropriate timing with a print signal, and is extinguished after printing is completed. When a plurality of prints are made for the same image, the developing unit 100 moves again so that the yellow developing unit 10 is located at the developing position. When all necessary developments have been completed, the developing unit 100 returns so that the standby portion 80 is located at the development operation position X, and waits for printing of the next image.

Similarly, when the color information of the image input signal indicates only magenta and black, the memory set 8 is called, the designated developing device moves and stops in the order of pattern No. 8, and the image forming body is stopped. Act on. In this case, the movement and stop of the unspecified yellow and cyan developing units to the developing operation position X are ignored, and the developing units jump over yellow according to the arrangement order from the standby portion 80, and the magenta developing unit ranks first. Transported to the developing position to develop the color,
Next, after the operation, the black developing device is carried to the developing operation position, ignoring cyan. Similarly, when the color information specifies magenta and cyan, the memory set 7 is called, and when the color information specifies cyan and black, the memory set 9 is called.

FIG. 3 shows an example of a flowchart for calling such a memory set.

The images formed in the designated colors in this manner are superimposed to form a mono-color, multi-color or full-color print.

[Effects of the Invention] As described above, according to the present invention, since the developing device is configured to be adjacently arranged in a fan shape, the space of the developing device can be reduced, and the developing device unit is reciprocated in a narrow angle range. Therefore, the time efficiency for switching the developing device is good. In addition, the fan shape reciprocates within a predetermined angle range so that it can be directly connected to the toner supply device by a flexible tube at the rear side of the developing device. Can be supplied with toner.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a main part of a color image forming apparatus according to the present invention, FIG. 2 is a block diagram of a print control unit, FIG. 3 is a flowchart of a page memory controller, and FIG. FIG. 5 is a sectional view showing an example of the developing device. DESCRIPTION OF SYMBOLS 1 ... Image forming body, 3 ... Image exposure device, 10, 20, 30, 40 ... Developing device, 18, 28, 38, 48 ... Flexible tube, 60 ... Toner supply device, 61, 62, 63, 64: toner tank, 80: standby part, 90: click mechanism, 100: developing unit, 200: page memory controller, 300: control unit

Claims (1)

(57) [Claims] 1. A developing device unit comprising a plurality of developing devices accommodating developers of different colors arranged side by side in a fan shape when viewed from the side, wherein the developing device unit is rotatably driven at a base. Is configured to be able to be stopped at the developing position of the photosensitive drum, and each of the toner tanks and developing units of each color of the toner supply device arranged independently of the developing unit is connected to a flexible tube. A color image forming apparatus, wherein the toner image can be supplied irrespective of the position of the developing device.