JPH04119369A - Rotary color development device - Google Patents

Abstract

PURPOSE:To decrease the number of components and to improve the assembly by providing an attachment/detachment restriction member which restricts the attachment and detachment of development units to and from a unit support body integrally with bearing members which supports the unit support body rotatably. CONSTITUTION:This device is equipped with the unit support body 14 which is supported rotatably on support shafts 12 and 13 supported rotatably on the bearing members 39 and 40 fixed to front and rear side plates 4 and 5 and the development units 15-17 which are supported detachably on the unit support body 14. Then when the development units 15-17 rotate to a development position A, the units 15-17 are pressed against a photosensitive body l by a pressing member 38 and restrained by the attachment/detachment from being attached to and detached from the unit support body 14. Namely, the attachment/ detachment restriction member 37 which restricts the attachment and detachment of the development units 15-17 is provided integrally with the bearing member 39 which supports the unit support body 14 rotatably. Consequently, the number of components is decreased and the assembly is improved.

Description

[Detailed description of the invention] (Industrial application field) This invention relates to an electrophotographic copying machine and printer.

The present invention relates to a rotary color developing device for facsimiles and the like.

(Prior Art) As one type of color developing device, a rotary color developing device is known, in which a plurality of developing units are rotatably arranged around a drum-shaped photoreceptor. 61
The device described in Japanese Patent No. 103175 is one in which a plurality of developing units are detachably supported on a unit support that is rotatable about a rotation center axis that is parallel to the rotation center axis of a photoreceptor. At the development position, development units containing developers of different colors are successively positioned according to the image forming process. Such a rotary developing device is advantageous in reducing the size of the photoreceptor and the device, and is characterized by good operability in terms of maintenance because the developing unit is detachable.

In the case of a rotary color developing device, a structure is required that prevents a developing unit supported by a unit support from being easily removed from the support. In response to this demand, a technique has been proposed in which an attachment/detachment regulating member is provided to restrict attachment/detachment of a unit placed at a developing position.

Furthermore, in the case of a system in which the unit support is rotated to replace the developing unit facing the photoconductor, when the unit support rotates, the developing roller, which partially protrudes from the development unit, comes into contact with the photoconductor. There is a problem with the developer falling and scattering. As a technology to deal with this,
] There is one described in the -59372 publication. In this technique, when the support unit is rotated, the support is moved in a direction in which the developing unit moves away from the photoreceptor.

The uniformity of the so-called development gap, which is the gap between the photoreceptor and the developing roller, means that a visible image formed by layering three or four colors of developer on the photoreceptor is transferred to transfer paper in a single transfer process. In the so-called non-contact flying development method in which full-color images are obtained, this is extremely important in obtaining uniform image quality. In particular, in a non-contact non-magnetic component development system in which a thin layer of non-magnetic developer is formed on the surface of a developing roller to perform non-contact development, it is required to maintain gap accuracy against image unevenness. As a technique to deal with this, the developing unit is rotatably supported on the unit support, and the developing unit that has rotated to the developing position is pressed by a pressing means to bring the developing roller close to the photoreceptor. something is proposed. In this technique, a gap maintaining ring is provided on the developing roller, and when the unit is pressed, this ring comes into contact with the surface of the photoreceptor to maintain a constant distance between the developing roller and the surface of the photoreceptor.

(Problems to be Solved by the Invention) The pressing means that presses the developing unit toward the photoreceptor at the developing position and the member that restricts the attachment and detachment of the developing unit are
Since they are each provided independently, there is a problem that the structure is complicated and the number of parts is large.

In addition, although consideration has been given to preventing toner scattering when the unit support is rotated when it is placed in the developing position or in the standby position, it is not effective in preventing toner scattering when the developing unit is attached or removed. No technology proposals have been made. This poses a problem in terms of operability when a user attaches and detaches the developing unit and maintainability for a service person.

SUMMARY OF THE INVENTION Accordingly, a first object of the present invention is to provide a rotary color developing device that has a reduced number of parts and is easy to assemble.

A second object of the present invention is to provide a rotary color developing device that prevents toner from scattering when the developing unit is attached and detached.

(Means for Solving the Problems) A first object of the present invention is to provide a plurality of unit supports rotatably about a rotation center axis disposed parallel to the rotation center axis of a photoreceptor. A predetermined developing unit is rotated to the developing position of the photoreceptor, and the developing unit rotated to the developing position is pressed by a suppressing member to the photoreceptor. In a rotary color developing device that performs development in close proximity, an attachment/detachment regulating member for regulating attachment/detachment of the development unit placed at the development position from the unit supporter is provided with an attachment/detachment regulating member that rotatably supports the unit supporter and is immovable. This is achieved by a rotary color developing device characterized by being provided integrally with a bearing member fixed to the member.

The present invention can also be achieved by a device in which both the attachment/detachment regulating member and the pressing member are integrally provided on a bearing member.

A second object of the present invention is to allow a plurality of developing units to be freely attached and detached in the axial direction to a unit support that is rotatably provided around a rotation center axis that is arranged parallel to the rotation center axis of a photoreceptor. A rotary color developing system in which a predetermined developing unit is rotated to the developing position of the photoreceptor, and the developing unit rotated to the developing position is pressed by a pressing member to bring it close to the photoreceptor to perform development. In the apparatus, the developing unit rotatably supports the unit support and is fixed to an immovable member, and the developing unit is placed at the developing position and the developing unit whose opening does not face upward is attached to and detached from the unit support. a bearing member integrally provided with an attachment/detachment regulating member for regulating the development unit and a pressing member for pushing the developing unit;
a one-way clutch that is provided in a part of the drive path for rotating the unit support and that enables the support to rotate in a fixed direction; and a one-way clutch that rotates the unit support to an arbitrary rotational position. This is achieved by a rotary color developing device characterized by having a unit rotating means.

(Function) When the developing unit supported by the unit support rotates to the developing position, the unit is pressed toward the photoreceptor by the pressing member, forming a gap between the photoreceptor and the developing roller. Ru. The developing unit that has been rotated to the developing position is restricted by the attachment/detachment regulating member and cannot be attached or detached from the unit support body.

When attaching or detaching the developing unit to or from the unit support, the unit rotating means is operated to rotate the unit support to a position where the opening of the developing unit to be attached or detached faces upward. At this time, the attachment/detachment of the other developing units 1 to 1 is regulated by the attachment/detachment regulating member.

(Example) Hereinafter, the present invention will be described in detail based on the illustrated example.

In FIGS. 1 and 2, reference numeral 1 indicates a drum-shaped photoreceptor, and reference numeral 2 indicates a rotary color developing device. The photoreceptor 1 is rotatably supported by a support shaft 3 supported by a front side plate 4 and a rear side plate 5 of the apparatus main body. A part of the front side plate 4 can be attached to and removed from an immovable main body side plate (not shown).

Around the photoconductor 1, along the direction of rotation thereof, there is a charger 6, an optical device (only the optical axis is shown) 7.degree. rotary color developing device 2. A transfer charger 82, a separation charger 9, and a cleaning device 1O are provided, respectively. The rotary color developing device 2 has a developing property of 31A.
At the transfer/separation position B, there is a registration roller 11 facing the
The transfer paper is fed in. The symbol ○ indicates the path of the transfer paper.

The rotary color developing device 2 is rotatably supported by a support shaft 12 rotatably supported by a bearing member 39 fixed to the front side plate 4 and a bearing member 4o fixed to the rear side plate 5. The unit support 14 is rotatably supported by a support shaft 13, and a plurality of developing units 15°1.6 and 1.7 are detachably supported on the unit support. The support shafts 1.2 and 1.3 are coaxial and arranged parallel to the support shaft 3 of the photoreceptor 1. In the illustrated example, the unit support 14 has three parts extending radially in three directions.
The developing unit 15, 16, 17 is supported between adjacent supporting parts 18, 19, 20, respectively. Each developing unit stores a developer of a different color. For example, unit 15 is a cyan developing unit that stores hasian developer, unit 16 is a magenta developing unit that stores magenta developer, and unit 17 is a yellow developer. This refers to the yellow developing unit that houses the agent.

Each developing unit has the same structure, except for the developer contained therein and the mounting position to the support 14. Therefore, the structure will be explained using the cyan developing unit 15 as a representative. As shown in FIGS. 1, 3, and 4, the cyan developing unit I5 includes a hopper 21 containing cyan developer and end plates 2 provided at both ends of the hopper.
2 (only one is shown), a fulcrum hole 24 formed in this end plate, which forms the center of rotation of the unit that is inserted into the outer end of the support portion 19 and fitted to the pivot shaft 23, and the end plate. 22 and a guide groove 26 that loosely fits into a guide rail 25 formed in the support part 19 in the axial direction, a guide groove 28 that loosely fits into a guide rail 27 formed in the support part 18, and A developer supply roller 2 rotatably provided in
9, a developing roller 30 made of an elastic material such as polyurethane foam and having a part of its peripheral surface protruding from the opening of the hopper; A developer thin layer forming plate 31 that forms a developer thin layer with a uniform thickness, and gap retaining rings 32 and 32 rotatably provided at both ends of the developing roller 30 (see FIG. 2). It has become. As shown in FIG.
The outer diameter of the developing roller 30 is larger than the diameter of the developing roller 30 by a predetermined dimension.

The cyan developing unit 15 is inserted into the support along the guide rail 25.27 formed on the unit support 14 by loosely fitting the guide groove 26.28 into the guide rail 25.27 formed on the unit support 14.
The support shaft 23 is rotatably mounted by fitting the support hole 24 into the support shaft 23.

In FIGS. 1 and 2, a bearing member 39 that rotatably supports the support shaft 12 is mounted so as not to rotate with respect to the front plate 4, and a detachable regulating member 37 is integrally attached to the bearing member 39. It is provided. As shown in FIG. 1, this attachment/detachment regulating member 37 faces the end plate 22 of the cyan developing unit 15 placed at the developing position and the magenta developing unit 16 whose hopper opening faces downward. , and prevents both units from being attached to and detached from the unit support body 14. The attachment/detachment regulating member 37 does not restrict attachment/detachment to the developing unit at the position where the yellow developing unit 17 in FIG. 1 is placed. Cams 38 and 38 as pressing members are integrally fixed to the bearing members 39 and 40, respectively.

In FIG. 2, the support shaft 13 of the unit support body 14 is
It is connected to the output shaft of a pulse motor 36 via gears 34 and 3.5 that mesh with each other, and rotates 120 degrees in accordance with the image forming process to position a predetermined developing unit at a developing position A (see FIG. 1). It looks like this.

On the back side of the cyan developing unit 15, leaf springs 33, 33 are fixed as elastic members that come into contact with the cams 38, 38 when the unit is placed at the developing position A. The magenta developing unit 16 and the yellow developing unit 17 are also provided with leaf springs as indicated by numerals 33A and 33B. A plate spring (not shown) is interposed between the guide groove 28 of the cyan developing unit 15 and the guide rail 27 of the support portion 18 into which it is loosely fitted, and the cyan developing unit 15 is removed from the photoreceptor 1. However, when the unit is rotated by the cam 38 at the developing position A, rotation in this direction is allowed. That is, the elasticity of the temporary spring (not shown) is set smaller than that of the leaf spring 33. Therefore, the magenta developing unit 16 and the yellow developing unit I7, which are placed at positions other than the developing position A, are moved from their respective fulcrums 1 to 1 by leaf springs (not shown).
6a and 17a as rotation centers and are urged to rotate in a direction away from the photoreceptor. This rotation is limited by the clearance between the kite rail and the guide groove.

The cams 38, 38 are disposed on the rotation locus of the leaf springs 33, 33, and press the cyan developing unit 15 placed at the developing position A toward the photoreceptor 1, as shown in FIG. are doing. The cyan developing unit 15 placed at this development value @A has a gap holding ring 32 of its developing roller 30.
．． 32 in contact with the circumferential surface of the photoreceptor 1.

A gap d (see FIG. 2) between the developing roller 30 and the circumferential surface of the photoreceptor 1 is maintained. It goes without saying that the spreading holding rings 32, 32 come into contact with the circumferential surface of the non-image forming part of the photosensitive woodwork. Other developing port unit 16 y 17 i: R, not shown, the developing roller is moved into the unit support body by being biased in the centripetal direction by a plate flexure (not shown), and is moved into the unit support body 14 without wobbling. Supported.

Let me briefly explain the image forming process here.

A color-separated electrostatic latent image is formed on the photoreceptor 1, which is charged to a predetermined polarity by the charger 6, by the exposure device 7. When this electrostatic latent image rotates to the development position A, the cyan developer in the thin developer layer formed on the circumferential surface of the developing roller 3o flies toward the electrostatic latent image and visualizes it. . When the blue color development with the cyan developer is completed, the unit support 1
4 is rotated 120 degrees counterclockwise, the yellow developing unit 17 is positioned at the developing position A, and the yellow image is exposed and developed.Finally, the magenta developing unit 16 is positioned at the developing position A to develop the red image. Therefore, on one photoreceptor, a color image is formed by superimposing three colors of developer. When the golden color development is complete, the transfer paper is fed towards the surface of the photoreceptor.
The image is transferred to this paper by a transfer charge 〒8.

The transfer paper onto which the color image has been transferred is separated from the surface of the photoreceptor by a separation charger 9, the image is fixed by a fixing device (not shown), and then the paper is discharged outside the machine as a color copy. After completing the transfer process, the surface of the photoreceptor 1 is cleaned by a cleaning device IO in preparation for the next image formation.

When development with the cyan developer is completed, the unit support 14 is rotated 120 degrees counterclockwise in FIG. 1. Then, the cyan developing unit 15 is rotated in the centripetal direction and retracts its developing roller into the support body.
The yellow developing unit 17 is positioned at the developing position A. In FIG. 1, in order to show the position of the developing roller of each unit, a portion of the roller is shown protruding from the peripheral surface of the support. The yellow developing unit 17 is connected to the leaf spring 3
When 3B comes into contact with the cam 33, the support, =Q I
When the developing roller 30 is rotated about 7 a and the developing process for each of the three colors is rotated, the gap retaining ring 32 is brought into contact with one circumferential surface of the photoreceptor to ensure the gap d.
In the developing unit, the plate spring 33 is pressed by the cam 38, so that the gap retaining rings 32 and 32 provided at both ends of the developing unit are brought into contact with the circumferential surface of the photoconductor 1, and the circumference of the photoconductor 1 is brought into contact with the circumferential surface of the photoconductor. The gap d between the two is always kept constant.

When removing the developing unit from the unit support 14,
Insert the developing unit you want to replace into the yellow developing unit (2) in Figure 1.
Rotate it to the unit 17 position. Since this unit is located at a position where it is not prevented from being attached or detached by the attachment/detachment regulating member 37, this unit 1-17 can be easily removed and a replacement unit can be attached. Moreover, since the yellow developing unit 17 is located at a position where the opening C of the unit faces upward, the toner adhering to the developing port 32A will not fall out when the unit is attached or detached. There is no toner scattering. If the attachment/detachment regulating member 40 does not prevent the magenta developing unit 16 from being attached or detached, the toner would fall and scatter when the magenta developing unit 16 is attached or detached because its opening faces downward.

In the example shown in FIG. 2, a separate cam 38 is integrally fixed to the bearing member 39, but as shown in FIG.

Both the cam 39a and the attachment/detachment regulating member 37 may be integrally molded into the bearing member 39. In this way, the number of parts can be further reduced.

Next, the second invention will be explained with reference to FIGS. 6 to 8. Components that are the same as those of the invention shown in FIGS. 1 and 2 are given the same reference numerals, and individual explanations will be omitted. The unit support shown in FIG. 1 supports three developing units, so when one unit is placed in the developing position, one unit has its opening facing upward and its toner is Can be attached and detached without scattering. But cyan developer.

When a black developer is used in addition to a magenta developer and a yellow developer, a unit is produced whose opening does not face upward. Second, the invention addresses this problem.

of the support shaft 12 fixed to the unit support 14,
A knob 41 serving as unit rotation means is fixed to a portion protruding from the front side plate 4. A positioning flange 14 is provided at the end of the unit support 14 near the rear plate.
a is formed. The flange 14a has a positioning recess 14b for positioning the developing roller 30 of the cyan developing unit 15 facing the photoreceptor 1, and a positioning recess 14b for positioning the developing roller 30A of the yellow developing unit 17 facing the photoreceptor 1. A positioning recess 14c and a positioning recess 14d for positioning the developing roller 30B of the magenta developing unit I6 facing the photoreceptor 1 are formed, respectively. A positioning pin 43 fixed to one end of the lever 44 engages and disengages from these positioning recesses.

The lever 44 is swingably supported by a shaft 45 which is equivalent to the rear plate 5, and the other end is connected to an actuator 47 of a solenoid 46 fixed to the rear plate 5.

The positioning pin 43 is connected to a spring 48 connected to the lever 44.
It is given a movement habit in the direction of engaging with the positioning recess.

As shown in FIG. 8, the attachment/detachment regulating member 37A, which is integrally formed with the bearing member 39 that rotatably supports the support shaft 12, allows its opening C to move upward when the unit support is rotated. It is formed and arranged in a shape that prevents the attachment and detachment of units 16 and 17 other than the unit that is directed towards the camera (the cyan developing unit 15 in the figure). When four developing units are provided, the attachment/detachment regulating member 37A has a shape and an arrangement position selected so that only one developing unit with an opening facing upward can be freely attached and detached, and the other three units can be prevented from being attached or detached. Ru.

In addition, the support shaft 13 of the unit support body 1-4 and the gears 3 and 1
A one-way clutch 42 is provided between the two.

This one-way clutch 42 is configured so that, although the pulse motor 36 serving as a drive motor transmits a driving force for rotating the unit support 14 counterclockwise to the support shaft 13, when the driving force is cut off, the unit support 14 is rotated counterclockwise. When rotating 14 counterclockwise, it acts in a direction that allows this rotation.

Then, when performing a normal developing operation, the unit support 14 has a positioning recess 14 as shown in FIG.
By engaging one of b-14d with the positioning pin 43, one of the developing units is made to face the photoreceptor 1. - When the color development is completed, the solenoid 46 is energized and the positioning pin 43 is moved to the positioning recess (14b).
Then, the pulse motor 36 and the unit support 14 are rotated 120 degrees so that the next unit, for example, the yellow developing unit 17, is opposed to the photoreceptor 1. Positioning pin 43
After being pulled out from the positioning recess, it rubs the periphery of the flange and engages with the next positioning recess 14c.

Now, for example, if you want to replace the cyan developing unit 5, operate the knob 41 to rotate the unit support 14, and as shown in FIG. Position the unit at the unit attachment/detachment position. At this time, the positioning action of the developing position by the positioning pin 43 may be canceled by turning on the No. 5 solenoid 46. Further, a positioning recess may be added to prevent rotation of the unit support body 14 at this unit attachment/detachment position, and one positioning means may be activated. As shown in FIG. 8, in the unit attachment/detachment position, the opening C of the unit faces upward, so that the toner adhering to the developing roller 30 does not fall and scatter when the unit is attached/detached.

In the unit attachment/detachment position shown in FIG.
The relative positions of the two are taken into consideration so that they do not engage with each other.

(Effects of the Invention) According to the first invention, the attachment/detachment regulating member for regulating the attachment/detachment of the developing unit supported by the unit support is provided integrally with the bearing member that rotatably supports the unit support. The number of parts can be reduced and ease of assembly is improved. Further, if a pressing member for pressing the developing unit toward the photoreceptor is integrally provided on the bearing member, the number of parts can be further reduced and ease of assembly can be improved.

According to the second invention, a one-way clutch is provided between the unit support and the separate movement path, and when the support is rotated by the unit support means, the opening of the developing unit supported by the support is rotated. Since the support body can be rotated to the unit attachment/detachment position where the developer unit faces upward, the developing unit can be replaced without scattering toner.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an image forming apparatus to which a rotary color developing device is applied, showing an embodiment of the first invention; FIG. 2 is a plan sectional view of the same as the above, showing an embodiment of the first invention; 3 is a perspective view showing the main parts of the developing unit, FIG. 4 is a perspective view showing the main parts of the unit support, FIG. 5 is a plan sectional view showing another embodiment of the first invention, and FIG. The figure is a plan sectional view of a main part of an image forming apparatus to which a rotary color developing device is applied, showing an embodiment of the second invention, and FIG. 7 is a front view showing the same unit support body.
FIG. 8 is a front view of the same as above showing the unit attachment/detachment position. 1... Photoreceptor, 2... Rotary color developing device, 3...
...Support shaft, 12.13...Support shaft, 15...Cyan developing unit, 16...Magenta developing unit, 1
7...Yellow developing unit, 18, 19.20...
・Support part, 21... hopper, 30... developing roller,
32... Gap retaining ring, 33... Leaf spring, 37
．． 37A... attachment/detachment regulating member, 38... pressing member, 3
9.40...Bearing member, 41...Unit rotation means, 42...One-way clutch. Agent Toru Kabayama (and 1 other person) Condolence δ Kuni 4.5 ) 7?54 Vision 1 [ 1G prisoner

Claims (1)

[Scope of Claims] 1. A plurality of developing units can be freely attached and detached in the axial direction to a unit support that is rotatably provided around a rotational axis that is arranged parallel to the rotational axis of the photoreceptor. A rotary color developing device that rotates a predetermined developing unit to a developing position of a photoconductor, and presses the developed unit that has been rotated to this development position with a pressing member to bring it close to the photoconductor to perform development. A detachment regulating member for regulating attachment and detachment of the developing unit placed at the development position from the unit support body is integrated with a bearing member that rotatably supports the unit support body and is fixed to the immovable member. A rotary color developing device characterized by being provided with. 2. The rotary color developing device according to claim 1, wherein a pressing member for pressing the developing unit is integrally provided with the bearing member provided with the attachment/detachment regulating member. 3. A plurality of developing units are each detachably supported in the axial direction on a unit support that is rotatably provided around a rotational axis disposed parallel to the rotational axis of the photoreceptor, and a predetermined development is performed. In a rotary color developing device in which a unit is rotated to a developing position of a photoreceptor, and the developing unit rotated to this developing position is pressed by a pressing member to perform development by bringing it close to the photoreceptor, the unit support an attachment/detachment regulating member which is rotatably supported and fixed to the immovable member, and which restricts attachment/detachment of the development unit placed at the development position and the development unit whose opening does not face upward from the unit support body; and a pressing member that presses the developing unit, and a bearing member that is provided in a part of a drive path that rotationally drives the unit support,
A rotary color developing device comprising: a one-way clutch that allows the support to rotate in a fixed direction; and a unit rotation means that rotates the unit support to an arbitrary rotational position.