JP3327626B2 - Image forming device - Google Patents

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 multi-color 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 using an electrophotographic system.

As shown in FIG. 8, the image forming apparatus has an image carrier 1 at a substantially central portion. An image is exposed on the image carrier 1 by an optical unit 107, and latent images of respective colors are sequentially formed. It is formed. Each time a latent image of each color is formed, the image carrier 1
Are developed in order by the developing cartridges D of 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 disposed around the image carrier 1.
A toner image of each color is sequentially formed thereon.

A transfer drum 103 is provided on the side of the image carrier 1 opposite to the developing cartridge D, and a sheet 102 is fed from the sheet feeding unit 101 to the transfer drum 103. Paper 102
, The tip of the gripper 103 on the outer periphery of the transfer drum 103
The transfer drum 103 is conveyed while being held on its outer periphery by the rotation of the transfer drum 103. The toner images of the respective colors formed on the image carrier 1 are sequentially superimposed and transferred onto a sheet 102 held on the outer periphery of the transfer drum 103 in an image transfer section facing the transfer drum 103, and are transferred to the sheet 10.
Thus, a multicolor image composed of four color toner images on 2 is obtained.

[0005] Paper 102 onto which four color toner images have been transferred
Then, the toner image is separated from the transfer drum 103 and transported to the fixing unit 104, where the toner image is fixed to fix the toner mixture of each color and the paper 102 to form a full-color permanent image. The paper 105 is discharged onto a paper discharge tray 106 via the paper tray 105 .

FIG. 12 and FIG.
As shown in, the developing device 12 constituting the cartridge body
And a protective member that covers the developing device 12 and rotatably (rotatably) accommodates the developing device 12 therein, that is, a cylindrical shell 13. The developing device 12 protrudes from the shell 13 at both ends. Rotating shaft 14. Each of the developing cartridges D is provided with the rotation support shaft 14 which is a rotation center axis.
The developing device 12 is rotatably held by a holding member (rotary unit) 108 of the developing cartridge switching mechanism, and as shown in FIG. 8, the image carrier is maintained in a state where the attitude of the developing device 12 is kept constant. The rotation for selecting and switching the developing cartridge is performed toward the developing position opposite to the developing cartridge 1.

The rotary unit 10 as a rotating body
Reference numeral 8 has a four-leaf clover shape, and is provided with a storage hole 108b formed of a substantially semicircular cutout for storing the developing cartridge D at four locations along the circumferential direction. As shown in FIG. 11, the developing cartridges D of the respective colors are housed in the housing holes 108b of the rotary unit 108 and are detachably mounted on the rotary unit 108.

The developing device 12 of the developing cartridge D is shown in FIG.
As shown in Fig. 2 , development that contains developer
Containing portion, i.e., composed of a toner containing portion 19 thereof adjacent the developing section 20., the toner containing portion 19, agitating and transporting member 18 for transporting and agitating the toner in the developing unit 20 is provided, the developing unit Reference numeral 20 denotes a developer carrier 15, a supply / peeling member 17 for supplying toner to the developer carrier and removing undeveloped toner thereon, and a layer thickness of the toner carried on the developer carrier 15. A regulating member 16 that regulates and imparts electric charge is provided.

As shown in FIGS. 12 and 13, both ends of the shell 13 of the developing cartridge D correspond to step portions 108a provided in the storage holes 108b of the rotary unit 108 shown in FIG. The leg 13a is provided, and when the leg 13a contacts the step 108a, the shell 13 of the developing cartridge D housed in the housing hole 108b is held non-rotatably with respect to the rotary unit 108.

When the developing cartridge D is moved to the developing position, the developer carrier 15 of the developing unit 12 in the shell 13 faces the image carrier 1 on the surface of the shell 13 opposite to the leg 13a. An opening 13b is provided for this purpose.

In each of the developing cartridges D, the developing device 12 is placed in a predetermined posture, in this embodiment, the toner storing portion 19 and the developing portion
In a horizontal position (the wall 12a separating the toner storage unit 19 and the developing unit 20 is vertical), that is, the parallel unit 14a of the rotating shaft 14 is horizontal. It is housed and mounted in the housing hole 108b.

The developing cartridge switching mechanism is shown in FIG.
As shown in FIG. 11, the disk-shaped driving side plate 7 rotates integrally with the rotary unit 108 around the non-rotating central axis 110 of the rotary unit 108.
Gears 9 and 10 that constitute a rotation attitude control mechanism of the developing device 12 are provided inside the driving side plate 7 in correspondence with each of the developing cartridges D. Further, each gear ( Gear (sun gear) meshing with planetary gear 9
Are fixedly mounted non-rotatably, and these gears 8, 9 and 10 constitute a planetary gear mechanism. Each of the above gears 10
A concave member 11 having a groove 11a whose one end is open is attached to the side of the developing cartridge D. In this embodiment, the groove 1a of the concave member 11 is horizontal.
The rotation support shaft 14 of the developing device 12 in the developing cartridge D mounted on the rotary unit 108 is fitted into the rotary shaft 1a with its parallel portion 14a horizontal. Normally, the gear 10 and the gear 8 are set to a reduction ratio of 1: 1.

According to the above-mentioned control mechanism, in order to move the developing cartridge D , a driving mechanism (not shown)
When the rotary unit 108 is rotated around the central axis 110 toward the developing position, the driving side plate 7 rotates in the same direction, whereby the gears 8, 9 and 10 perform planetary motion, and the concave shape of the driving side plate 7 is formed. The member 11 rotates in the opposite direction, and its groove 11a is kept horizontal. Therefore, the developing device 12 in which the rotating shaft 14 is fitted is used as the developing cartridge D.
The developing unit 12 is always kept in a horizontal position regardless of the movement of the developing cartridge D.

The developing cartridge D moved to the developing position
The pressing 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,
Are engaged. A pulley 29 is fixedly installed on a central shaft (pressing control shaft) 110 of the rotary unit 108, and a belt 30 is wound around the pulley 29 and a pulley 31 of a pressing control motor 32. The pressure control shaft 110 is rotated.

On the other hand, as shown in FIGS. 14 and 15, the rotary unit 108 is provided with a semi-cylindrical member 46 fixed to the apparatus body surrounding the pressure control shaft 110. A frame-shaped pressure member 111 rotatable around the shaft 47 is provided in the shape member 46, and the pressure member 111 is urged by a pressure spring (not shown) attached to the member 46. The developing cartridge D is pressed toward the image carrier 1. The cam 48 is fixed to the pressurizing control shaft 110, and the pressurizing and non-pressurizing of the developing cartridge D by the pressurizing member 111 is controlled by the rotation stop position of the control shaft 110.

At the time of pressurization, as shown in FIG. 14, the cam 48 does not contact the projection 49 provided on the pressurizing member 111, and the pressurizing member 111 applies the pressing force by the above-mentioned pressing spring to the developing cartridge D. As a result, the developing cartridge D is pressed and moved in the direction of the image carrier 1, and the developer carrier 15 is positioned with respect to the image carrier 1. At the time of non-pressurization, as shown in FIG. 15, the rotation of the pressurization control shaft 110 causes the cam 48 to rotate, comes into contact with the projection 49, and
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-described conventional image forming apparatus, a slide pressing mechanism for the developing cartridge is required in addition to the developing device rotation attitude control mechanism for the developing cartridge D, which raises the problem of cost increase. In order to slide the entire developing cartridge, it is necessary to press the developing cartridge D against the image carrier 1 with a pressing force greater than the weight of the developing cartridge, and a high torque is required for the driving source 32 for controlling the pressing. There was a problem that was.

An object of the present invention is to pressurize and position the developing device by using the developing device rotation attitude control mechanism of the developing cartridge, and to omit the pressing and positioning mechanism, thereby achieving cost reduction. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

[0020]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides a cartridge body having a developer accommodating portion for accommodating a developer and a rotatable developer carrier, and a relative movement with respect to the cartridge body at a position covering and exposing the developer carrier. A developing cartridge having a protective member, a rotating body for holding a plurality of developing cartridges, and an image carrier on which a latent image to be developed by the developer is formed. In an image forming apparatus in which a developing cartridge opposed to an image carrier is switched to form an image on an image carrier with a developer contained in each developing cartridge, the rotating body includes a rotation center shaft provided on the cartridge body. A rotating gear provided coaxially, a planetary gear engaged with the gear, and fixed so as not to rotate with respect to the rotating body during rotation of the rotating body. And a sun gear arranged at the rotation center position of the rotating body and engaged with a planetary gear, wherein the cartridge body maintains the fixed posture regardless of the position in the rotating direction of the rotating body. It revolves around the sun gear,
The apparatus further has a driving unit for rotating the sun gear, and the cartridge body of the developing cartridge facing the image carrier rotates by the force of the driving unit via the sun gear and the planetary gear. By this rotation, the spacers provided at both ends of the developer carrier are
The image forming apparatus is characterized in that the developer carrier is positioned with respect to the image carrier by abutting on both ends of the image carrier.

[0021]

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

As shown in FIG. 9, the center gear 8 of the rotation control drive side plate 7 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, by extending the central axis 110, a gear 121 having a torque limiter to slip provided when torque above a specified torque to the central axis 110 is applied, the gear 121 Is connected to and driven by a pressurizing rotation control motor 132 as driving means .

Other configurations of the image forming apparatus of this embodiment are basically the same as those of the conventional image forming apparatus described with reference to FIGS. Is omitted.

In this embodiment, the rotary unit 108 for selecting and switching the developing cartridge D is used.
When the pressurizing rotation control motor 132 is rotated in one direction after the rotation operation, 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
Is pressed and positioned. Usually, a space roller is provided at both ends of the developer carrier 15, and the space roller contacts the both ends of the image carrier 1 by positioning, so that the image carrier 1 and the developer carrier 15 are brought into contact with each other. They are opposed with a certain gap.

[0025] At this time, the control motor 132 by an angle of more than the developer carrying member 15 abuts against the image bearing member 1, although the developing unit 12 is adapted to be rotated to rotate, the torque of the gear 121 Since the slip occurs in the limiter, the developer carrier 15 is held in a positioning state with a certain gap from the image carrier 1. After that, the motor 132 holds the stop position until the development is completed, and after the development is completed, the motor 132 is rotated by a fixed amount in the reverse direction, 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 115 , respectively, and the gear 114 and the gear 115 are connected by a positioning operation. The developer carrier 15 is driven in conjunction with the image carrier 1, and the gear 115 and the gear 1 are driven.
In order to prevent poor pressurization when 14 tooth tips interfere,
At the end of the rotation driving of the developing device 12 by the control motor 132, the rotation driving of the developing device 12 is overlapped by a certain amount of time after the driving operation of the developer carrier 15 by the image carrier 1 is started. finish.

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

In the above embodiment, the torque limiter is provided on the gear 121 driven by the motor 132, 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 developing cartridge positioning mechanism in another embodiment of the image forming apparatus of the present invention, and FIG.
FIG.

In this embodiment, as shown in FIGS. 4 and 5, a notch gear 125 is further provided integrally with the rotation pressure control shaft (central shaft) 110 at a position opposite to the gear 8 so that the developing cartridge D The developing device 12 is characterized in that a gear 126 meshing with the gear 125 is also provided.

The shell 13 of the developing cartridge D is provided with an opening 13c for meshing the gears 125 and 126. Further, since the developing cartridge D is attached to and detached from the rotary unit 108 in the direction of the arrow in FIG. 4 , the gear 125 is turned over half the circumference of the gear 125 so that the gear 125 can be rotated by half to allow the attaching and detaching of the developing cartridge D. A notch 125a is provided.

According to the present embodiment, the developing device 12 rotates the control motor 132 to rotate the gear 10 and the gear 1.
The developer carrier 15 is positioned at the image carrier 1 by being pressed by both ends of the developing device 12.

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

In the present embodiment, the rotary units 10 correspond to the rotation center shafts 14 at both ends of the developing cartridge D.
8 is also characterized in that rotation control mechanisms are provided at both ends thereof.

As in the first embodiment, when the rotation pressure control shaft 110 is rotated by the motor 132, the developing unit 12 in the shell 13 of the developing cartridge D is rotated in the direction of the image carrier 1, and the developing cartridge D is developed. The developer carrier 15 of the container 12 is pressed against the image carrier 1 and positioned.

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. 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. When the developing cartridge D is mounted, the developing unit cover 127 is held by the unit 108, and only the developing device 12 can rotate on the cover 127.

[0038]

As described above, the present invention relates to a cartridge body having a developer accommodating portion for accommodating a developer and a rotatable developer carrier, and a position for covering the developer carrier and a position for exposing the cartridge. A developing member having a protection member movable relative to the cartridge body, a rotating body holding a plurality of developing cartridges, and an image carrier on which a latent image developed by the developer is formed. In an image forming apparatus in which the developing cartridge facing the image carrier is switched by rotating the rotating body and an image is formed on the image carrier with the developer contained in each developing cartridge, the rotating body is provided on the cartridge body. A rotating gear provided coaxially with the rotation center axis, a planetary gear engaged with the gear, and fixed so as not to rotate with respect to the rotating body during rotation of the rotating body. A sun gear which is arranged at the center of rotation of the rotating body and engages with the planetary gear; the cartridge body keeps a constant attitude regardless of the position in the rotating direction of the rotating body. The apparatus further includes a driving means for rotating the sun gear; the cartridge body of the developing cartridge facing the image carrier is provided with a driving means via a sun gear and a planetary gear; The developer carrier is rotated by force.
Spacers provided at both ends of the image carrier contact both ends of the image carrier
In addition, since the developer carrier is positioned with respect to the image carrier, a pressure control mechanism for positioning the developing device, which is the cartridge body, can be omitted, and the cost can be reduced. Further, since the developing cartridge does not slide, the holding accuracy of the developing cartridge to the holding member is improved, and the vibration and noise due to the reduction of the backlash are also reduced.

[Brief description of the drawings]

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

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

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

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

FIG. 5 is a front view showing a state after the positioning of the developing cartridge by the positioning mechanism of FIG. 4;

FIG. 6 is a cross-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 a state where a developing unit cover is provided in the developing cartridge of FIG. 6;

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

9 is a front view showing a driving side plate and a developing device rotation attitude control mechanism provided on one side of a rotary unit of the switching mechanism of the image forming apparatus of FIG. 8;

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

FIG. 11 is a side view showing a method of attaching 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 a positioning mechanism of the developing cartridge.

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Image carrier 12 Developing device (cartridge main body) 13 Shell (protection member) 19 Toner storage part (developer storage part) 108 Rotary unit (rotary body) 110 Central axis ( Spinning pressure control axis) 132 Pressure control motor ( Driving means) D developing cartridge

Claims (1)

(57) [Claims] 1. A cartridge body having a developer accommodating portion for accommodating a developer and a rotatable developer carrier, and a movable relative to the cartridge body at positions covering and exposing the developer carrier. A developing cartridge having a protective member, a rotating body for holding a plurality of developing cartridges, and an image carrier on which a latent image to be developed by the developer is formed. In an image forming apparatus in which a developing cartridge facing a body is switched to form an image on an image carrier with a developer contained in each developing cartridge, the rotating body is coaxial with a rotation center axis provided in the cartridge main body. The provided rotating gear, a planetary gear engaged with the gear, and fixed so as not to rotate with respect to the rotating body during rotation of the rotating body, and A sun gear that is disposed at the rotation center position of the rotating body and engages with a planetary gear, wherein the cartridge body maintains a fixed posture regardless of the rotational direction position of the rotating body. The apparatus further includes a driving unit for rotating the sun gear, wherein the cartridge body of the developing cartridge facing the image carrier includes the sun gear and the planetary gear. and rotation by the force of said drive means via the front by the rotation operation
The spacers provided at both ends of the developer carrier bear the image bearing member.
An image forming apparatus, wherein the developer carrier is positioned with respect to the image carrier by contacting both ends of the carrier.