JPH03288880A - Multicolor image recorder - Google Patents

Abstract

PURPOSE:To reduce the size and cost of the multicolor image recorder and to obtain images of high quality having no ununiformity of density by fixing plural developing devices and cleaning means, displacing a carrier and controlling intervals among respective means. CONSTITUTION:Since the developing devices 7 to 10 and the cleaning device 13 are respectively held at prescribed positions, the carrier 1 is moved by interval regulating rollers 14a to 14d and the rollers 14a to 14d and developing rollers for the devices 7 to 10 are pressed through a spacer 42, the carrier 1 can be prevented from coming into contact with the devices 7 to 10, the speed of the carrier 1 is not changed and images of high quality can be obtained. In addition, the carrier 1 can be carried as a flat shape by providing the carrier 1 with flexibility. Thereby, plural developing devices 7 to 10 having the same shape can be used in common and the size and cost of the recorder can be reduced. Since the devices 7 to 10 and the means 13 are fixed, their driving mechanisms are simplified and the reliability of the recorder is sharply improved.

Description

[Detailed description of the invention] Industrial application field This invention (Dai) Conventional technology related to a multicolor image recording device that records a multicolor image using an electrostatic image carrier (hereinafter referred to as a carrier) It is used as a multicolor image recording device that records multicolor images by repeating charging, exposure, and development at the same location on the body to form images of different colors overlappingly, and then transferring them all at once to a transfer material. This technique is disclosed in Japanese Patent Publication No. 103665/1982.As shown in FIG.
One color image is formed each time the carrier 101 rotates, and this process is repeated multiple times to form a multicolor image on the carrier, which is then transferred all at once to recording paper. In order to prevent color mixing and image disturbance, the developing device is constructed so as to be separated from the carrier.A specific technique for separating the developing device from the carrier is disclosed in Japanese Patent Laid-Open No. 63-261283.

As shown in FIG. 5, a plurality of developing devices 104 each having a thin layer of developer formed on a developing roller 103 are arranged around the outer periphery of a drum-shaped carrier 101.
The cleaning means is configured to rotate an eccentric cam 105 provided on the back side of the device to press it against the carrier 101 during development, release the eccentric cam 105 by half a turn during non-development, and move it away from the carrier 101 using a return spring 106. A specific technique for separating and separating C and t is shown in, for example, Japanese Unexamined Patent Publication No. 62-242984. In this technique, as shown in FIG. 6, a cleaning device 108 equipped with a fur brush roller 107 that rotates at high speed is pressed into contact with the carrier 101 by a plunger 109 to sweep away the developer remaining on the surface. However, the problem to be solved by the invention is that the plate is configured to be separated from the spring 110. However, with the above configuration, it is possible to move a plurality of developing devices and cleaning means toward and away from the carrier (and to drive them). The mechanism and detachment mechanism were complicated.Also, when the carrier is rigid and drum-shaped, multiple developing units are arranged on the curved part of the outer circumference of the drum-shaped carrier, resulting in a radial arrangement. The different shapes of developing devices in some parts make compatibility and common use difficult, which can lead to problems with increased costs.
On the other hand, the spacing ii between the carrier and the developing device, which affects the density and resolution of the image, must be regulated with high precision. Conventionally, the carrier and the developing roller were configured to come into contact with each other via a spacing regulating member during development. When a developing device with a large load is placed close to or separated from the developing device, the speed of the carrier will vary greatly, and the image may be distorted during image formation (for example, when a laser beam is scanned with a rotating polygon mirror to expose the carrier to light and form an electrostatic latent image). In view of this problem, the present invention has been developed to reduce the size of the device by fixing the developing device and cleaning means and controlling the spacing by displacing the carrier. It is an object of the present invention to provide a multicolor image recording device that can reduce costs and obtain high-quality images without uneven density. A flexible, endless carrier for carrying an electrostatic image that is stretched across rollers and conveyed in one direction is provided, and an electrostatic image forming means and developers of different colors are housed on the outer peripheral surface of the carrier. A plurality of developing means, a transfer means for transferring the developed image onto a transfer material, and a cleaning means for removing the developer on the carrier are arranged in order in the moving direction of the carrier, and the inner peripheral surface side of the carrier At a position facing each of the developing means and the cleaning means, a spacing regulating roller having a cutout portion having a D-shaped cross section in a wider range than the carrier is thrown; and the carrier is displaced by the spacing regulating roller. According to the present invention, with the above-described structure, the developing device and the cleaning device are held at predetermined positions, and the carrier is moved by the spacing regulating roller. By pressing the interval regulating roller and the developing roller of the developing device through a spacer, the carrier and the developing device do not come into contact with each other, and high quality images can be obtained without fluctuations in the speed of the carrier. By making it flexible, it can be transported in a flat shape, and multiple developing devices with the same shape can be used in common, making the device more compact and cost-effective, while fixing the developing device and cleaning means. This simplifies the drive mechanism and significantly improves reliability.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1, 2, and 3.

In FIG. 1, 1 is a flexible, endless carrier having an organic photoconductive layer such as phthalocyanine on its surface.
2 is a drive roller that conveys the carrier l in the direction A; 3 is a driven roller thereof; 4 is a tensioning means such as a spring that moves the driven roller 3 and tensions the carrier 1; 5 is a tensioning device that charges the carrier 1 uniformly. Scorotron charger 6 is a laser scanner that linearly exposes and scans the carrier 1 in the axial direction according to an input signal to form an electrostatic image; 7 to 10 are Bk (black), Y (yellow), M (magenta) Developing devices 11 each contain a C (cyan) developer and develop the electrostatic image on the carrier 1, and the transfer band tit 12 transfers the developed image to the transfer material.The transfer band tit 12 removes static electricity from the carrier 1 after transfer. A static eliminator 13 is a cleaning device that removes developer remaining after transfer. 1st @
In FIG. 2, ff114 is a spacing regulating roller provided on the inner peripheral surface side of the carrier l, facing the developing units 7 to 10 and the cleaning unit 13, and displaces the carrier l. 13 is variable every 1/2 rotation (FIG. 1 shows a state in which the distance regulating roller 14a brings the carrier 1 close to the black developing device 7, and other distance regulating rollers 14b to 14e are spaced apart. ) Suya 15 is the recording material 1
1F! 6 is a cassette stocked with recording paper 15;
17 is a paper feed roller that feeds the recording paper 15 sheet by sheet;
18 is a timing roller that controls feeding of the recording paper 15 in accordance with the leading edge of the image on the carrier l; 19 is a fixing method that heats and fixes the image on the recording paper 15; and 20 is a discharge roller. 21 is a back roller that keeps the optical path length from the laser scanner 6 to the carrier l constant.

Developing unit 7 to +011 The developer contained in the container 31 is supplied to the developing roller 33 by the supply roller 32 and pressed by the blade 34 made of an elastic material, so that a thin layer of the developer with a thickness of about 30 μm is deposited on the developing roller 33. form a layer. The developing roller 33 is electrically conductive, and its surface is sandblasted to facilitate the formation of a layer of developer. The developer is frictionally charged by the supply roller 32 and the blade 34 so that the surface potential on the developing roller 33 becomes 30 to 50V.

The cleaning device 13 (Dai) The fur brush roller 41, which is flocked with fur having an insulation resistance of 106 to 108 Ωcm, is rotated in contact with the carrier L on a counter, and the developer is removed by applying a bias voltage of opposite polarity to the developer. A spacer ring 42 having a diameter smaller than the outer diameter of the fur brush roller 41 is loosely inserted at both ends of the fur brush roller 41, and contacts both ends of the spacing regulating roller 14e to control the amount of contact between the fur brush roller 41 and the carrier l. Figure 2 shows a detailed configuration example of the interval regulating roller 14 and developing roller 33 shown in Figure 1.
The spacer has a notch with an abbreviated cross section in the axial center of the carrier l in an area wider than the width of the carrier l, and both ends of the spacer are in contact with insulating spacers 35 provided at both ends of the developing roller 33. 35 (When retaining the expression, the carrier 1 and the developing roller 33
Although the rollers 11 are configured to be thicker than the carrier 1 so as to have a gap of 120 μm, an electrically operated half-rotation clutch 36 is connected to one end of the gap regulating roller 14. 1/2 rotation circle rotation control is performed.

FIG. 3(a) shows the cross-sectional shape of the central part of the spacing regulating roller 14, and as shown in FIG. 3(b), the displacement amount δ of the contacting carrier 1 reaches a maximum within the range of α angle. The other angles are shaped to be smoothly displaced by making the displacement of the carrier l parabolic with respect to the rotation angle.When the spacing regulating roller 14 is rotated as shown in FIG. The carrier 1 approaches the developing roller 33 with a gap equal to the difference in thickness between the spacer 35 and the carrier l.
A rigid material such as iron-based metal is preferable in order to cope with the tension and keep the gap with high precision.Also, since it comes into frictional contact with the inner surface of the carrier 1 that is continuously conveyed, a fluorine-based resin with excellent wear resistance is used on the surface. The operation of this structure will be explained with reference to FIG. To form an electrostatic latent image corresponding to the color black, the spacing regulating roller 14a facing the black developing device 7 is rotated half a turn to bring the carrier l close to the developing roller 33, and the non-contact image of the carrier 1 is placed on the developing roller 33. When a bias voltage of approximately the same potential as the exposed area is applied, the developer flies toward the exposed area of the carrier 1 and the potential has attenuated, and the latent image is developed (negative/positive reversal development). The interval regulating roller 14a is rotated half a turn to move the carrier 1 away from the black developing device 7. When the carrier l rotates once, the black image is charged again by the scorotron charger 5, and an electrostatic latent image corresponding to, for example, yellow is formed by the laser scanner 6.
rotates half a rotation, brings the carrier l close to the developing roller 33, and develops yellow. Thereafter, magenta, cyan and magenta images are formed in the same manner as in step 1. X, to form a multicolored image on carrier 1
During cyan development, the recording paper 15 is conveyed to the transfer section in alignment with the leading edge of the image, and is transferred onto the recording paper by a transfer charger. Even though the recording paper 14 is fixed by the fixing device and ejected from the machine, the carrier l after the transfer is neutralized by the static eliminator and comes into contact with the fur brush roller by half a rotation of the spacing regulating roller 14e facing the cleaning device, and the remaining developer is removed. After the cleaning is completed, the spacing regulating roller 14e rotates half a turn and separates from the fur brush roller to prepare for recording the next image again.

The distance between the carrier and the developing roller is maintained with high accuracy by disposing the plurality of developing units (i.e., on the upstream side of the drive roller 2, that is, on the tension side of the carrier) between the drive roller 2 that conveys the carrier and the driven roller 3. As described above, according to the multicolor image recording apparatus of this embodiment, the flexible carrier is moved by the interval regulating roller provided at a position facing the developing device and the cleaning means. It is possible to provide a highly reliable device in which the developing device and the cleaning means can be held at predetermined positions, the driving mechanism thereof and the mechanism for bringing the carrier into and out of contact are simple and highly reliable.

Furthermore, since the carrier does not come into direct contact with the heavily loaded developing device, there is no impact, and speed fluctuations of the carrier are significantly reduced, making it possible to obtain high-quality images.

By making the carrier in the form of a sheet, it is possible to convey the carrier flatly, which reduces the overall size of the device and improves the accuracy of the gap between the developing roller and the carrier. Although this can be achieved by improving accuracy and reducing costs, in this embodiment, the developing means uses a developing device that develops without contacting the carrier.At least the color to be initially formed (
For example, it is possible to use a two-component magnetic brush developing device that develops by contacting the carrier, but it is also possible to use a fur brush roller as a cleaning means and to separate it from the carrier with a spacing regulating roller. Instead of a fur brush roller, a rubber blade made of elastic material is used that can remove fine powder developer and developer filmed on the carrier.

It is also possible to move the blade into contact with and away from the carrier by rotating the blade (°C. At this time, it is preferable to provide a flat back plate instead of the spacing regulating roller at the position facing the blade. In order to remove the streaky residual developer that occurs, it is more preferable to use a blade/fur brush roller in combination. Also, it is better to arrange multiple developing devices in a straight line on the carrier. to reduce costs by
Furthermore, it is easily possible to separate and independently replace each one according to the frequency of use.

Effects of the Invention By making the carrier flexible, the carrier can be brought close to or in contact with the developing units or cleaning means while holding a plurality of developing units or cleaning devices at predetermined positions. It is possible to provide a highly reliable device with a simple drive mechanism and carrier separation mechanism, and it is also possible to reduce the size and cost of the device.

Furthermore, since the carrier does not come into direct contact with the heavily loaded developing roller, there is no impact, and speed fluctuations of the carrier are significantly reduced, making it possible to obtain high-quality images.

[Brief explanation of the drawing]

Fig. 1 shows the overall structure of a multicolor image recording apparatus according to an embodiment of the present invention; Fig. 2 shows a perspective view showing the relationship between the spacing regulating roller and the developing roller; Fig. 3(a) shows a cross section of the spacing regulating roller. Figure 3(b) shows the characteristics showing the displacement amount of the carrier with respect to the rotation angle of the spacing regulating roller. l... Electrostatic image carrier 3... Driven roller, 5... Device 6... Laser scanner, image droplet 11... Transfer charging method 13... Cleaning device roller, 15... Recording grade

Claims (7)

[Claims] (1) A flexible and endless electrostatic image carrier is provided that carries an electrostatic image stretched by at least a plurality of rollers and conveyed in one direction, and an electrostatic image carrier that forms an electrostatic image on its outer peripheral surface is provided. an electrostatic image forming means, a plurality of developing means each containing a developer of a different color to develop the electrostatic image, a transfer means for transferring the developed image to a transfer material, and a plurality of developing means for developing the electrostatic image; and cleaning means for removing attached developer are arranged in order in the moving direction, and the electrostatic image carrier is displaced at a position facing each of the developing means on the inner peripheral surface side of the electrostatic image carrier. A multicolor image recording device equipped with an interval control means for controlling an interval between the developing means and the developing means. (2) At least one of the plurality of developing means applies a bias voltage having the same polarity as the developer to a conductive developing roller carrying a non-magnetic developer, and the developing roller 2. The multicolor image recording device according to claim 1, wherein the multicolor image recording device is configured to contact the spacing control means via an insulating spacer that is thicker than the electrostatic image carrier. (3) Provide a flexible, endless electrostatic image carrier that carries an electrostatic image stretched by at least a plurality of rollers and conveyed in one direction; an electrostatic image forming means, a plurality of developing means each containing a developer of a different color to develop the electrostatic image, a transfer means for transferring the developed image to a transfer material, and a plurality of developing means for developing the electrostatic image; and cleaning means for removing attached developer are arranged in order in the moving direction, and the electrostatic image carrier is placed at a position facing each of the developing means and the cleaning means on the inner peripheral surface side of the electrostatic image carrier. A multicolor image recording device comprising interval control means that is displaced and controls intervals between the developing means and the cleaning means. (4) Claim 3, wherein the cleaning means comprises a conductive fur brush roller to which a voltage of opposite polarity to that of the toner is applied, and the electrostatic image carrier is brought into contact with and separated from the fur brush roller by the interval control means. multicolor image recording device (5) The spacing control means includes a spacing regulating roller having a notch portion having a D-shaped cross section at least in an area wider than the width of the electrostatic image bearing member in the axial center thereof, and a plurality of developing means that control the spacing regulating roller. The multicolor image recording apparatus according to claim 1 or 3, further comprising a control means for controlling the rotation according to a selection signal of the cleaning means. (6) A flexible, endless electrostatic image carrier is provided that carries an electrostatic image that is stretched between at least one pair of driving rollers and a driven roller and is conveyed in one direction, and the electrostatic image is formed on the outer peripheral surface of the flexible electrostatic image carrier. a plurality of developing means each containing a developer of a different color and developing the electrostatic image; a transfer means transferring the developed image to a transfer material; Cleaning means for removing developer attached to the image carrier are disposed in order in the moving direction, and the plurality of developing means are disposed between the drive roller and the driven roller on the upstream side of the drive roller, and the electrostatic image A multicolor image recording apparatus, comprising: an interval control means for displacing the electrostatic image carrier and controlling a distance between the electrostatic image carrier and the developing means, at a position facing each of the developing means on the inner peripheral surface side of the carrier. (7) The multicolor image recording apparatus according to any one of claims 1 to 6, wherein the transfer means is disposed at a position facing an inner driving roller of at least one pair of rollers for conveying the electrostatic image carrier.