JPH0327066A - Rotary developing device - Google Patents

Abstract

PURPOSE:To surely set the distances between respective developing rollers and a photosensitive body and to easily transfer developer containers at the same time with the aid of simple constitution by arranging the developing rollers at prescribed positions and simultaneously disposing the circular developer containers to prescribed positions. CONSTITUTION:Developer chambers 92A - 92C respectively having the hollow cylinder-shaped developer containers where toner for respective colors are housed are formed in a developer device 9. Then, the developing rollers 9A - 9C which project to the outside every chamber are arranged at the position where they are brought into contact with the inside of a prescribed circle which is crossed to the surface part of the photosensitive body in a developing area. On the other hand, the respective containers 92A - 92C are disposed so that the outside circumference part of the hollow cylinder thereof makes the prescribed circle which is separated from the surface part of the photosensitive body by a fixed quantity in the developing area. By such simple constitution, the distances between the respective developing rollers and the photosensitive body in the developing area are surely set and the developer containers are easily rotated and transferred at the same time.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a photosensitive material in which one of a plurality of developing rollers carries an electrostatic latent image by rotationally moving a hollow cylindrical developer container. The present invention relates to a rotary developing device that is selectively conveyed to a developing area that faces a body.

[Prior Art] In general, in various image forming devices such as copying machines and printers, an electrostatic latent image corresponding to an image is formed on a photoreceptor, and an electrostatic latent image is formed on a developing roller provided in a developing device. A two-component developer or a two-component developer is held in the
The developer on the developing roller is carried into the developing area, which is the area facing the photoreceptor, by the conveying action of the developing roller. In the developing area, toner in the developer is supplied to the electrostatic latent image to perform a developing operation, so that a visible toner image is obtained. As a developing device used in such an image forming apparatus,
Rotary types have been known for some time.

This rotary developing device is equipped with a hollow cylindrical developer container, and a plurality of developer chambers are formed inside the developer container to accommodate the developer. A developing roller, a portion of which protrudes toward the developer, is arranged in each of the developer chambers. As the developer container is rotated, one of the developing rollers is transported to a developing area, and the developing roller is selectively placed at a predetermined position for development. Such a rotary developing device has the advantage that a plurality of developing units can be accommodated in a small space, and the image forming apparatus can be downsized.

[Problems to be Solved by the Invention] However, in such a rotary developing device, each developing roller must be placed at a predetermined position in the developing area by rotating the entire device. It is difficult to position the developing roller and the photoreceptor at the same position, so it has been a challenge to maintain a constant distance between the developing roller and the photoreceptor at all times.

In the apparatus described in Japanese Patent Application Laid-Open No. 61-105565, after a designated developing unit is arranged facing the photoreceptor side, the developing roller is pushed outward, that is, toward the photoreceptor side. The distance between the photoreceptor and the developing roller is set constant. However, with this device. Since the distance 111 setting step must be executed every time the developing roller is switched, smooth developing operation is difficult and the device mechanism becomes complicated.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rotary developing device that can reliably set the distance between each developing roller and a photoreceptor using a simple mechanism. [Means for Solving the Problem] In order to achieve the above object, the invention described in claim 1 is characterized in that a plurality of developer chambers for storing a developer are formed inside a hollow cylindrical developer container. In addition, each of the above developer chambers has a. Each developing roller is arranged so that a part thereof protrudes outward from the developer container. In a rotary developing device in which one of the developing rollers is selectively disposed at a predetermined position for development by rotational movement of a container, each of the developing rollers is arranged in contact with the surface of the photoreceptor in the developing area. The hollow cylindrical developer containers are arranged at positions that are inscribed in predetermined intersecting circles, and the outer circumferential portion of the hollow cylindrical developer container is formed to form a predetermined circle that is spaced a certain amount from the surface of the photoreceptor in the development area. It has a structure in which Further, in the invention described in claim 2, a plurality of developer chambers for accommodating the developer are formed inside a hollow cylindrical developer container, and each of the developer chambers has a developer container. The developing rollers are arranged so that a part of the developing rollers protrudes outward, and the rotation of the developer container is performed with respect to the developing area formed in the area facing the photoreceptor carrying the electrostatic latent image. In a rotary developing device in which one of the developing rollers is selectively disposed at a predetermined position for development by movement, one of the developing rollers is pressed against the back side of the portion corresponding to the developing area of the photoreceptor, and a distance between the photoreceptor and the developing roller and a backup roller that is movable in a direction perpendicular to the conveying direction of the photoreceptor so as to advance and retreat a portion of the photoreceptor corresponding to the development area toward the developer container side; and a roller positioning member provided in the developer container so as to receive the backup roller at a predetermined position with a constant value. [Function] In the means having the configuration described in claim 1, when each developing roller is arranged to face the surface portion of the photoreceptor to perform development, the outer surface portion of the developing roller is placed on the photoreceptor side. The surface of the photoreceptor is displaced by pressure contact. At this time, the developing position is set at the pressure contact portion between the developing roller and the photoreceptor, and the developing position is the same for each developing roller. In addition, while each developing roller is being conveyed to the developing area, the outer periphery of the developer container is rotated a certain amount away from the surface of the photoreceptor, thereby ensuring smooth rotational transfer of the developer container. It is supposed to be done.

In the means having the structure recited in claim 2, when each developing roller is arranged facing the surface portion of the photoreceptor to perform development, it is pressed against the back side of the portion of the photoreceptor corresponding to the development area. The backup roller is moved toward the developer container in a direction perpendicular to the conveying direction of the photoreceptor, thereby also moving the portion of the photoreceptor corresponding to the development area toward the developer container. The backup roller is received by a roller positioning member at a predetermined position, so that the distance between the photoreceptor and the developing roller is kept constant, and the same developing gap is maintained for each developing roller. It has become so.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 3 shows a color copying machine to which the present invention is applied. In this figure, an endless transfer belt 1 is stretched around a rotating roller 2 and a driven roller 3 in a substantially horizontal direction, and the transfer paper S fed in the direction of the arrow by a paper feed roller 4 is The image is conveyed on a transfer belt 1.

Further, the document table 5 is provided parallel to the direction in which the transfer belt 1 is disposed, and is configured to be driven back and forth in the directions indicated by arrows a and b.

An original (not shown) is set on the original platen 5, and a light image corresponding to a color image of the original is transmitted through a convergent light transmitting array 6, a filter 7, etc., and is transmitted as a latent image carrier. The image is formed and dispensed onto the photoreceptor belt 8, thereby forming an electrostatic latent image on the photoreceptor belt 8. Such electrostatic latent images are formed for each color separation. The photoreceptor belt 8 is stretched across twelve support rollers 8a, 8b, and 8c placed in an immovable state.

On the other hand, corresponding to the electrostatic latent images of each color, developing rollers 9A, 9B, and 9G for toner of each color provided as developer carriers in the rotary developing device 9 are used as developing rollers 9A, 9B, and 9G, which are opposed to the photoreceptor belt 8. Each color electrostatic latent image is developed by each color toner supplied from each developing roller 9A, 9B, and 9C, and a toner visible image corresponding to each color is obtained. It looks like this. In the photoreceptor belt 8, a developing area is formed between the support rollers 8a and 8b.

As described above, when the transfer paper S carried by the transfer belt 1 passes through the transfer section 1l, the visible toner image of the first color on the photoreceptor belt 8 is transferred to the transfer paper by the transfer charger 12. Transferred to S. During this transfer, the transfer belt 1 is driven in the eight directions of arrows, that is, in the opposite direction to the forward movement direction of the document table 5, and after the document table 5 completes its forward movement, it is moved backward. When the rear end of the transfer paper S passes through the transfer section 1, the transfer belt L is reversed, and the upper belt portion is moved in the direction of arrow B, which is opposite to the direction of arrow 8, in preparation for the next transfer. ．． Then, by repeating the same transfer process, the visible toner image of the second color and the visible toner image of the third color are transferred onto one sheet of transfer paper in such a manner that they are superimposed on each other so that no positional deviation occurs. Ru.

After the final color toner visible image is transferred, the transfer paper S passes between a pair of static elimination chargers 13 and is received into a transfer paper fixing system 14 consisting of a pair of heating and pressure rollers, where it is fixed and then machined. It will be discharged outside. Next, as shown in FIG. 1, the copying device 9 is equipped with a developer container 92 made of a cylindrical hollow frame. It is set up so that it can be moved. In addition, the developer container 9
2 is divided into three developer chambers 92A and 92B by a partition wall extending in a radial curve from the rotation center o1.
, 92C, and each of these developer chambers 92A,
Yellow (Y), magenta (M) in 92B, 92C,
Each cyan (C) color developer is stored separately. Further, within each of the developer chambers 92A, 92B, and 92C, developing rollers 9A, 9B, and 9G are provided, respectively, so that a portion thereof protrudes outside the developer container 92. The respective distances connecting the rotation centers of these developing rollers 9A, 9B, and 9C and the rotation center 0e of the developer container 92 are set to match each other. Further, each of the developing rollers 9A, 9B, and 9C is arranged at a position where it can come into contact with the photoreceptor belt 8, so that a developing area is formed in the opposing contact portion between the two. That is, the developing rollers 9A, 9B, and 9G are arranged so as to be inscribed in a predetermined circle C1, and the predetermined circle Cl is set to intersect with the surface of the photoreceptor belt 8 in the developing area. ing. At this time, the outer periphery of the hollow cylindrical developer container 92 is formed as a predetermined circle C2, and the predetermined circle C2 is set to be a certain amount away from the surface of the photoreceptor belt 8 in the development area. has been done.

Furthermore, toner supply rollers 94A, 94B, 94G are arranged so as to be in contact with the respective developing rollers 9A, 9B, 9C, and the developing chambers 92A, 92B,
The toner of each color stored in 92C is an agitator.
96A, 96B, 96C and toner supply roller 94
The developing roller 9 is
It is supplied to and attached to A, 9B, and 9C.

The toner adhered to the surface portions of the developing rollers 9A, 9B, 9G is moved by the rotational conveyance action of the developing rollers 9A, 9B, 9C, and the toner is transferred to the developing rollers 9A, 9B;
The toner layer is formed into a uniform layer by metering blades 95A, 95B, and 95G for regulating the toner layer, which are pressed against the surface portion of toner layer 9C.

Furthermore, this toner thin layer is applied to the developing rollers 9A, 9B, 9
The material is carried into the development area by the rotational conveyance action of G, and is subjected to the above-mentioned development operation here. Toner remaining on the developing rollers 9A, 9B, 9C after development is removed by toner layer peeling rollers 93A, 93B, 93C that are in pressure contact with the surface portions of the developing rollers 9A, 9B, 9C.
This causes the developing rollers 9A, 9 to be scraped off.
B and 9C will be initialized.

Note that each developer chamber 92A, 92B, 92
Yellow (Y), magenta (M) in G, 92B, 92C
), cyan (C) will be consumed in sequence, but when the amount of stored developer falls below a certain value, a toner end detection device (not shown) will indicate the need for toner replenishment. At the same time the copying machine is displayed, the entire operation of the copying machine is stopped. Further, the outer frame portion of the developer container 92 includes the developer chambers 92A, 92B. 9
An opening for replenishing toner is formed in 2C, and opening/closing lids 91A, 91B, and 91C are attached so as to be openable and closable so as to open or close the toner replenishment opening. This opening/closing lid 91A, 91B, 9C
is hinged to the outer frame of the developer container 92, and is mounted so as to be flipped open radially outward.

In the developing device in such an embodiment, for example, the developing roller 9A among the developing rollers 9A, 9B, and 9C is disposed facing the surface of the photoreceptor belt 8, as shown in FIG. Then, the outer surface of the developing roller 9A is pressed against the photoreceptor belt 8, and the surface of the photoreceptor belt 8 is displaced. At this time, a developing position is formed at the pressure contact portion between the developing roller 9A and the photoreceptor belt 8, and as a result, the developing rollers 9A, 9
The development position is the same for both B and 9G. Further, as shown in FIG. 2, while the developing rollers 9A, 9B, and 9C are being conveyed to the developing area, the outer circumferential portion of the developer container 92 rotates a certain amount away from the surface portion of the photoreceptor belt 8. This allows the developer container 92 to be rotated and transferred smoothly.

Further, in the embodiments shown in FIGS. 4, 5, and 6, a backup roller 81 is disposed so as to be able to press against the back side of the portion of the photoreceptor belt 8 corresponding to the developing area.

This backup roller 81 is rotatably attached to the tip of an arm 83 that swings about a support shaft 84, and is thereby capable of reciprocating movement in a direction perpendicular to the conveyance direction of the photoreceptor belt 8. ing. Furthermore, this backup roller 81 is provided with a moving mechanism (not shown), and by swinging the backup roller 8 through the moving mechanism, the portion of the photoreceptor belt 8 corresponding to the developing area is moved to the developing area. It is designed to move forward and backward toward the drug container 92 side. Further, a small-diameter guide roller 82 is coaxially attached to the backup roller 8l.

On the other hand, a roller positioning member 98 that supports the backup roller 81 is provided on the side plate 97 of the developer container D92.
is formed to protrude radially outward by a predetermined amount. This roller positioning member 98 is provided at a position corresponding to the installation portion of each of the developing rollers 9A, 9B, and 9G, and has a semicircular notch formed at the radial tip portion of each roller positioning member 98. A stop 99 is provided.

As shown in FIGS. 5 and 6, this locking portion 99 is connected to the guide roller 82 on the backup roller 8l side.
It is designed to be mated to the In this way, the locking portion 99 on the developing device side and the guide roller 82 on the pack-up roller 8 1 side are fitted to each other, so that the photoreceptor belt 8 which is pressed and held by the backup roller 81 and the developing device The distance between the rollers 9A, 9B, and 9G, that is, the development gap, is kept constant.

In the apparatus of this embodiment, for example, a developing roller 9A is placed facing the surface of the photoreceptor belt 8, as shown in FIG. 4, in order to perform development.

Next, the backup roller 8 that was placed at a position away from the back side of the portion corresponding to the developing area of the photoreceptor belt 8
1 is oscillated and moved toward the developer container 92 side, the backup roller 81 is brought into pressure contact with a portion of the photoreceptor belt 8 corresponding to the developing area, and the portion of the photoreceptor belt 8 corresponding to the developing area is close to the developing roller 9A side. be done. Then, the guide roller 82 on the backup roller 81 side is connected to the locking portion 9 on the developing device side.
9, the photoreceptor belt 8 and the developing roller 9A
The distance, that is, the development gap, is set to a preset value. As a result, the developing roller 9
The same development gap is maintained for all of A, 9B, and 9C. As a modification of this embodiment, it is also possible to configure a developing device in which the photoreceptor belt 8 and the developing rollers 9A, 9B, and 9G are brought into contact with each other. [Effect of the invention] As described above, in the invention described in claim 1, the developing position is the same for each developing roller, and the rotational transfer of the developer container is performed smoothly. As shown in FIG. Since the configuration is adopted in which the rollers are formed to form a predetermined circle separated by a certain distance, the distance between each developing roller and the photoreceptor can be reliably set using a simple mechanism.

Further, in the invention described in claim 2, the distance between the photoreceptor and the developing roller is kept constant, and the same developing gap is maintained for each developing roller. A simple structure is adopted in which the backup roller, which is pressed against the back side of the part corresponding to the developing area of the body, is received by the roller positioning member at a predetermined position keeping the distance between the photoreceptor and the developing roller constant. The mechanism can reliably set the distance m between each developing roller and the photoreceptor.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional explanatory diagram showing a schematic structure of a rotary developing device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional explanatory diagram showing a state in the middle of movement of the rotary developing device shown in FIG. 3 is an explanatory side view showing a color copying machine as an example of an image forming apparatus to which the present invention is applied, and FIG. 4 is a schematic configuration of a rotary developing device in another embodiment of the present invention. 5 and 6 are a partially enlarged cross-sectional explanatory view and a partially enlarged external perspective view showing a positioning portion of the rotary developing device shown in FIG. 4. 8... Photoreceptor belt, 9... Developing device, 9A, 9B
, 9C...Developing roller 92... Developer container, 9
2A, 92B, 92G...Developer chamber, 81...Backup roller, 98...Roller positioning member,
99...(stupid name) niδlfi Figure d Figure 9.9 Figure 2 i4

Claims (1)

[Scope of Claims] 1. A plurality of developer chambers for accommodating developer are formed inside a hollow cylindrical developer container. The developing rollers are arranged such that a part of the developing rollers protrudes from the surface of the developing roller, and the developing rollers are arranged so that each of the developing rollers is rotated and moved by the rotational movement of the developer container with respect to the developing area formed in the area facing the photoreceptor carrying the electrostatic latent image. In a rotary developing device in which one of the rollers is selectively disposed at a predetermined position for development, each of the developing rollers is inscribed in a predetermined circle that intersects with the surface portion of the photoreceptor in the development area. and the outer periphery of the hollow cylindrical developer container is formed to form a predetermined circle that is spaced a certain amount from the surface of the photoreceptor in the development area. Rotary developing device. 2. A plurality of developer chambers for accommodating the developer are formed inside the hollow cylindrical developer container, and a portion of each developer chamber protrudes outward from the developer container. One of the developing rollers is arranged as shown in FIG. In a rotary developing device that is selectively disposed at a predetermined position for development, the developing area corresponding portion of the photoreceptor is pressed against the back side of the developing area corresponding portion, and the developing area corresponding portion of the photoreceptor is exposed to the developer. a backup roller that is movable in a direction perpendicular to the conveying direction of the photoconductor so as to advance and retreat toward the container side; and a backup roller that is installed at a predetermined position to maintain a constant distance between the photoconductor and the developing roller. a roller positioning member provided on the developer container so as to receive the roller positioning member.