JPH06317982A - Multicolor image forming device - Google Patents

Abstract

PURPOSE:To provide a multicolor image forming device capable of eliminating a pressurizing/positioning mechanism by using the rotational attitude control mechanism of a developing cartridge, for pressurizing and positioning. CONSTITUTION:The developing cartridge D of each color is constituted so as to freely rotatably house a developing unit 12 having a rotary center shaft 14 in a shell 13, the rotary center shaft 14 is projected from the shell 13 and held by the rotary gear 10 of the rotational attitude control mechanism provided on the driving side plate 7 of the rotary unit 108 of a switching mechanism and the developing unit 12 is rotated centering the shaft 14 and the attitude of the rotation is kept constant, in accordance with the rotary action of the developing cartridge D to a developing position by the unit 108. After the movement to the developing position is completed, the developing unit 12 is further rotated centering the shaft 14, to pressurize/position the developing unit 12 on the image carrier. Thus, the pressurizing control mechanism for positioning the developing unit 12 can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an electrophotographic system or the like, and more particularly to a multicolor image forming apparatus such as a full color image.

[0002]

2. Description of the Related Art FIGS. 8 to 15 show a conventional multicolor image forming apparatus for obtaining a multicolor image by utilizing an electrophotographic system.

As shown in FIG. 8, the image forming apparatus has an image carrier 1 substantially in the center thereof, and an image is exposed on the image carrier 1 by an optical unit 107 to sequentially form a latent image for each color. It is formed. Each time a latent image of each color is formed, the image carrier 1
The developing cartridges D for the respective colors, that is, the yellow developing cartridge Dy, the magenta developing cartridge Dm, the cyan developing cartridge Dc, and the black developing cartridge Db, which are arranged around the image bearing member 1, are sequentially developed to develop the image carrier 1.
Toner images of respective colors are sequentially formed on the top.

A transfer drum 103 is installed on the opposite side of the image carrier 1 from the developing cartridge D, and the paper 102 is fed from the paper feed section 101 to the transfer drum 103. Paper 102
Grips the tip of the gripper 103 on the outer periphery of the transfer drum 103.
It is gripped by f, and is held and conveyed on the outer periphery thereof by the rotation of the transfer drum 103. The toner images of the respective colors formed on the image carrier 1 are sequentially superposed and transferred onto the paper 102 held on the outer periphery of the transfer drum 103 at the image transfer portion facing the transfer drum 103, and the paper 10 is transferred.
A multicolor image consisting of four color toner images is obtained on 2.

Paper 102 on which four color toner images have been transferred
Is then separated from the transfer drum 103 and conveyed to a fixing unit 104, where the toner images are fixed to mix the toners of the respective colors and fix the toner on the paper 102 to form a full-color permanent image. It is discharged onto a paper discharge tray 106 via 105. It has a rotation spindle 14.

The developing cartridge D is shown in FIGS.
As shown in FIG. 2, the developing device 12 and a cylindrical shell 13 that covers the developing device 12 and rotatably (rotatably) accommodates the developing device 12 inside the developing device 12 have shells at both ends. It has a rotary support shaft 14 protruding from 13. Each developing cartridge D is held by the holding member (rotary unit) 108 of the developing cartridge switching mechanism so that the developing device 12 can rotate about the rotation support shaft 14, and FIG.
As shown in FIG. 3, with the posture of the developing device 12 maintained constant, the developing cartridge is rotated toward the developing position facing the image carrier 1 for selecting and switching the developing cartridge.

The rotary unit 108 is in the shape of a four-leaf clover, and has an accommodating hole 108b having a substantially semicircular cutout for accommodating the developing cartridge D at four locations along the circumferential direction. Is provided. As shown in FIG. 11, the developing cartridge D of each color is housed in the housing hole 108 b of the rotary unit 108 and is detachably mounted on the rotary unit 108.

The developing unit 12 of the developing cartridge D is shown in FIG.
As shown in FIG. 2, the toner storage portion 19 is roughly divided into a toner storage portion 19 and a developing portion 20 adjacent to the toner storage portion 19.
An agitating / conveying member 18 that agitates the toner and conveys the toner to the developing unit 20 is provided.
Supplying / peeling member 17 for supplying toner to this and peeling off undeveloped toner thereon, and regulating member 16 for regulating the layer thickness of the toner carried on the developer carrying member 15 and for imparting electric charge thereto. Is provided.

At both ends of the shell 13 of the developing cartridge D, the rotary unit 108 shown in FIG.
The leg portion 13a corresponding to the step portion 108a provided in the accommodation hole 108b is provided, and the leg portion 13a abuts the step portion 108a, whereby the developing cartridge D accommodated in the accommodation hole 108b is The shell 13 is held non-rotatably with respect to the rotary unit 108.

On the surface of the shell 13 opposite to the leg 13a side, when the developing cartridge D is moved to the developing position, the developer carrier 15 of the developing device 12 in the shell 13 faces the image carrier 1. The opening 13b is provided for this purpose.

Each developing cartridge D has the developing device 12 in a predetermined posture, in this embodiment, the toner storage portion 19 and the developing portion 20.
Are horizontally adjacent to each other in a horizontal direction (the wall 12a partitioning the toner storage portion 19 and the developing portion 20 is vertical), that is, the parallel portion 14a of the rotary support shaft 14 is horizontal, and the rotary unit It is accommodated and mounted in the accommodation hole 108b of 108.

The developing cartridge switching mechanism is shown in FIG.
And as shown in FIG. 11, the disc-shaped drive side plate 7 that rotates integrally with the rotary unit 108 around the non-rotating central axis 110 of the rotary unit 108.
Gears 9 and 10 that form a rotation posture control mechanism of the developing device 12 are provided inside the driving side plate 7 corresponding to each developing cartridge D, and the center shaft 110 has each gear 10. A gear 8 that meshes with is fixedly installed non-rotatably, and these gears 8, 9 and 10 constitute a planetary gear mechanism. Developing cartridge D for each gear 10 described above
A concave member 11 having a groove 11a having one end opened is attached to the side, and in this embodiment, the rotary unit 108 is mounted in the groove 11a with the groove 11a of the concave member 11 being horizontal. The rotary support shaft 14 of the developing device 12 in the developing cartridge D is fitted with its parallel portion 14a horizontal. Normally, the gear 10 and the gear 8 have a reduction ratio of 1: 1.
Is set to.

According to the above control mechanism, when the rotary unit 108 is rotated around the central axis 110 toward the developing position in order to move the developing cartridge D, the driving side plate 7 is rotated in the same direction, which causes The gear 8, the gear 9, and the gear 10 make a planetary motion, and the concave member 1 of the driving side plate 7
1 rotates in the opposite direction, keeping its groove 11a horizontal. Therefore, the developing device 12 fitted with the rotation support shaft 14 is rotated in the developing cartridge D in the same direction as the concave member 11 and in the opposite direction, and the developing device 12 is always maintained in the horizontal posture regardless of the movement of the developing cartridge D. To be done.

The developing cartridge D moved to the developing position
The pressurization and positioning of the image carrier 1 are performed as follows.

That is, as shown in FIG. 10, a pressurizing control motor 32 is provided on the apparatus main body side, and a pulley 31 is attached to this.
Are engaged. A pulley 29 is fixedly installed on a central shaft (pressure control shaft) 110 of the rotary unit 108, and a belt 30 is wound around the pulley 29 and a pulley 31 of a pressure control motor 32. The pressure control shaft 110 is rotated.

On the other hand, the rotary unit 108 is provided with a semi-cylindrical member 46 fixed to the apparatus main body side surrounding the pressure control shaft 110, and the shaft 47 is used as a fulcrum in the semi-cylindrical member 46. Rotating frame-shaped pressing member 11
1, the pressing member 111 is biased by a pressing spring (not shown) attached to the member 46, and the developing cartridge D is pressed toward the image carrier 1 by the pressing member 111. Then, the cam 48 is fixed to the pressurizing control shaft 110, and the control shaft 1
Pressing and non-pressurizing the developing cartridge D of the pressing member 111 is controlled by the rotation stop position of 10.

As shown in FIG. 14, the cam 48 does not come into contact with the projection 49 provided on the pressing member 111 during the pressing operation, and the pressing member 111 acts on the developing cartridge D by the pressing force of the pressing spring (not shown). As a result, the developing cartridge D is moved by pressure in the direction of the image carrier 1, and the developer carrier 15 is positioned with respect to the image carrier 1. When the pressure is not applied, the cam 48 is rotated by the rotation of the pressure control shaft 110 as shown in FIG.
1 is rotated in the direction of the arrow in the figure to separate the developing cartridge D from the image carrier 1 against the pressing force of the pressing spring.

[0018]

However, in the above-mentioned conventional image forming apparatus, in addition to the developing device rotation posture control mechanism of the developing cartridge D, the slide pressing mechanism of the developing cartridge is required, which causes a problem of cost increase. In order to slide the entire developing cartridge, it is necessary to pressurize the developing cartridge D against the image carrier 1 with a pressure greater than the weight of the developing cartridge, and a high torque is required for the drive source 32 for pressurizing control. There was a problem of being done.

It is an object of the present invention to pressurize and position the developing device by utilizing the rotating attitude control mechanism of the developing device of the developing cartridge, and to omit the pressing and positioning mechanism, thereby reducing the cost. The object is to provide an image forming apparatus that is capable of some extent.

[0020]

The above object can be achieved by an image forming apparatus according to the present invention. In summary, the present invention provides a developing cartridge of each color including a developing unit having at least a developing unit having a developer carrier and a developer accommodating unit accommodating a developer, and a support container accommodating the developing unit. , The developing cartridges of the respective colors are detachably mounted on a holding member, and are rotated around an axis parallel to the axis of the image carrier to move to a developing position facing the image carrier, and A developing cartridge switching mechanism for switching the developing cartridge for developing the latent image on the image carrier by pressing and positioning the developer carrier of the developing cartridge moved to the apparatus toward the image carrier. In the color image forming apparatus, the developing unit of each developing cartridge has a rotation center axis, and the rotation center axis rotatably supports the development unit in the support container, and It is held by a drive transmission member provided on the holding member so that the developing device rotates about the rotation center axis independently of the rotation operation of the developing cartridge by the holding member. Its posture is variable,
Then, after the completion of the movement of the developing cartridge to the developing position, the developer carrying member of the developing device is pressed against the image carrying member by rotating the developing device at that position.
A multicolor image forming apparatus characterized by being positioned.

[0021]

Embodiment 1 FIG. 1 is a sectional view showing a developing cartridge positioning mechanism in an embodiment of the multicolor image forming apparatus of the present invention.

As shown in FIG. 9, the central gear 8 of the drive side plate 7 for rotation control is a rotary unit (holding member).
Although it is fixed to the central axis 110 of the rotation center of 108,
In this embodiment, as shown in FIG. 1, a gear 121 having a torque limiter that extends the central shaft 110 and slips when a torque of a specific torque or more is applied to the central shaft 110 is provided. Pressurized rotation control motor 13
The feature is that it is connected to 2 and driven.

Since the other construction of the image forming apparatus of this embodiment is basically the same as that of the conventional image forming apparatus described with reference to FIGS. 8 to 15, a drawing of the image forming apparatus itself and its description will be given. Is omitted.

In the present embodiment, the rotary unit 108 for selecting and switching the developing cartridge D.
When the pressurizing rotation control motor 132 is rotated in one direction after the rotation operation of, the developing device 12 in the shell 13 of the developing cartridge D is rotated (rotated) as shown in FIG.
As shown in FIG. 3, the developer carrier 15 is the image carrier 1.
Is pressed and positioned. Usually, spacer rollers are provided at both ends of the developer carrier 15, and the spacer rollers come into contact with both ends of the image carrier 1 by positioning, so that the image carrier 1 and the developer carrier 15 are separated from each other. Opposed with a certain gap.

At this time, the control motor 132 is rotated so that the developing device 12 rotates about an angle larger than the contact of the developer carrying member 15 with the image carrying member 1. Since the limiter causes a slip, the developer carrier 15 is held in a positioning state with a certain gap with the image carrier 1. After that, the motor 132 holds the stop position until the end of the development, and is rotated in the opposite direction by a certain amount when the development is completed, and the developing device 12 returns to the state of FIG.

As shown in FIG. 2, the image carrier 1 and the developer carrier 15 are provided with a gear 114 and a gear 113, respectively, and the gear 114 and the gear 113 are connected by a positioning operation. , The developer carrier 15 is driven in association with the image carrier 1, but the gear 113 and the gear 1
In order to prevent pressurization failure when the 14 tooth tips interfere,
At the end of the rotation drive of the developing device 12 by the control motor 132, the rotation drive of the developing device 12 is performed such that the developing device 12 is overlapped by a certain amount of time after the driving operation of the developer bearing member 15 is started by the image bearing member 1. finish.

As described above, according to this embodiment, the rotation posture control mechanism of the developing device 12 of the developing cartridge D causes
Since the developer carrier 15 can be pressed and positioned with respect to the image carrier 1, the pressure positioning mechanism can be omitted, and the cost can be reduced.

In the above embodiment, the gear 121 driven by the motor 132 is provided with the torque limiter, but the same limitation may be imposed by the step out of the motor 132.

Embodiment 2 FIG. 4 is a sectional view showing a positioning mechanism of a developing cartridge in another embodiment of the multicolor image forming apparatus of the present invention, FIG.
Is also a front view.

In this embodiment, as shown in FIGS. 4 and 5, a notch gear 125 is integrally provided at a position opposite to the gear 120 of the rotation pressure control shaft (central shaft) 110, and the developing cartridge D is provided. The developing device 12 is also characterized by being provided with a gear 126 that meshes with the gear 125.

The shell 13 of the developing cartridge D is provided with an opening 13c for meshing the gear 125 and the gear 126. Since the developing cartridge D is attached to and detached from the rotary unit 108 in the direction of the arrow in the figure,
The cutout portion 1 is formed over substantially half the circumference of the gear 125 so that the developing cartridge D can be attached and detached by rotating the gear 1215 a half turn.
25a is provided.

According to this embodiment, the developing device 12 rotates the control motor 132 to cause the gear 10 and the gear 1 to rotate.
The developer carrying member 15 is rotated by 25 and pressed at both ends of the developing device 12 to position the developer carrying member 15 on the image carrying member 1.

Embodiment 3 FIG. 6 is a plan view showing a positioning mechanism of a developing cartridge in still another embodiment of the image forming apparatus of the present invention, FIG.
Is also a front view.

In this embodiment, the rotary unit 10 is associated with the rotation center shafts 14 at both ends of the developing cartridge D.
8 is also characterized in that a rotation control mechanism is provided at both ends thereof.

As in the first embodiment, the rotation pressing control shaft 110 is rotated by the motor 132, so that the developing device 12 in the shell 13 of the developing cartridge D is rotated toward the image carrier 1 to develop. The developer carrier 15 of the container 12 is pressed and positioned on the image carrier 1.

Further, in this embodiment, each developing cartridge D
Is provided with a cover 127 that covers the developing unit 20 of the developing unit 12, and the developing unit cover 127 is rotatably attached to the rotation center shaft 14 of the developing unit 12.

The developing cartridge D to which the developing unit cover 127 is attached is attached to and detached from the rotary unit 108 in the direction of the arrow in FIG. By mounting the developing cartridge D, the developing unit cover 127 is held by the unit 108, and only the developing device 12 can rotate with respect to the cover 127.

[0038]

As described above, in the multicolor image forming apparatus of the present invention, the developing cartridge for each color, which is mounted on the holding member of the switching mechanism and is conveyed to the developing position facing the image carrier, is provided in the support container. A developing device having a rotation center axis is rotatably accommodated therein, and the rotation center axis is projected from the support container and held by a drive transmission member provided on a holding member, and the holding member rotates the developing cartridge. As a result, the developing device is rotated about the rotation center axis to maintain its posture constant, and after the completion of the movement of the developing cartridge to the developing position, the developing device is further rotated about the rotation center axis at the developing position. By doing so, the developer carrying member of the developing device is pressed and positioned on the image carrying member, so that the pressurizing control mechanism for positioning the developing device can be omitted and the cost can be reduced. It is. Further, since the developing cartridge does not slide, the holding accuracy of the developing cartridge on the holding member is improved, and vibration due to reduction of rattling,
It is also effective in reducing noise.

[Brief description of drawings]

FIG. 1 is a sectional view showing a positioning mechanism of a developing cartridge in an embodiment of a multicolor image forming apparatus of the present invention.

2 is a front view showing a state before the positioning of the developing cartridge by the positioning mechanism of FIG. 1. FIG.

FIG. 3 is a front view showing a state after the same positioning.

FIG. 4 is a cross-sectional view showing a positioning mechanism of a developing cartridge in another embodiment of the multicolor image forming apparatus of the present invention.

5 is a front view showing a state after the developing cartridge is positioned by the positioning mechanism of FIG.

FIG. 6 is a sectional view showing a developing cartridge positioning mechanism in still another embodiment of the image forming apparatus of the present invention.

FIG. 7 is a front view showing the developing cartridge cover of FIG. 6 provided with a developing section cover.

FIG. 8 is an overall configuration diagram showing a conventional multicolor image forming apparatus.

9 is a front view showing a drive side plate and a developing device rotation posture control mechanism provided on one side of a rotary unit of the switching mechanism of the image forming apparatus of FIG.

FIG. 10 is a front view showing a rotation method of a pressure control shaft for positioning the developing cartridge.

FIG. 11 is a side view showing how to attach the developing cartridge to the rotary unit.

FIG. 12 is a sectional view showing a developing cartridge.

FIG. 13 is a perspective view of a developing cartridge.

FIG. 14 is a front view showing the positioning mechanism of the developing cartridge.

FIG. 15 is a front view showing the cancellation of the positioning of the developing cartridge.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image carrier 12 Developing device 19 Toner storage unit 108 Rotary unit 110 Central axis (rotation pressure control axis) 132 Pressure control motor D Development cartridge

Claims (1)

[Claims] 1. A developing device having at least a developing section having a developer carrier and a developer accommodating section accommodating a developer,
By attaching the developing cartridge of each color including the supporting container accommodating the developing device and the developing cartridge of each color to the holding member in a detachable manner, the cartridge is rotated about an axis parallel to the axis of the image carrier. While moving to the developing position facing the image carrier, the developer carrier of the developing cartridge moved to the developing device is pressed and positioned in the direction of the image carrier to detect the latent image on the image carrier. In a multicolor image forming apparatus having a developing cartridge switching mechanism for switching a developing cartridge for developing an image, a developing device of each developing cartridge has a rotation center axis, and the rotation center axis has the development in the support container. While supporting the vessel rotatably,
The developing device is held by a drive transmission member provided on the holding member so as to project from the supporting container, whereby the developing device is centered on the rotation center axis independently of the rotation operation of the developing cartridge by the holding member. And its posture is variable, and after the completion of the movement of the developing cartridge to the developing position, the developing device is rotated at that position so that the developer carrying member of the developing device is moved to the image carrying member. A multi-color image forming apparatus characterized in that it is pressed and positioned to.