JP2000352853A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing a rotary type developing unit from being inadvertently rotated by generating a rotation preventing torque in the case of replenishing a developing device with toner. SOLUTION: The rotary type developing unit 21 is provided with a 1st gear 23 fixed on the center shaft 22 of the unit 21 and rotating together with the shaft 22, a shaft member 24 whose rotation is regulated while it is pivotally supported by a device main body 100 in parallel with the shaft 22, and a 2nd gear 26 capable of moving in the axial center direction while it is meshed with the member 24 and regulated by the rotating direction of the member 24. Then, the rotation preventing torque is generated when the 1st gear 23 is meshed with the 2nd gear 26. Thus, a rotation preventing mechanism works even though a main power source is turned off.

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 such as a copying machine, a facsimile, and a printer.
The present invention relates to an image forming apparatus that performs development by moving a desired developing device to a developing position by rotating a rotary developing device unit rotatably supported by an apparatus main body.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus of this type, a rotary developing device provided rotatably in proximity to a photosensitive member as a latent image carrier and having a plurality of developing devices around a rotation center is known. Some units have a rotary developing device in which a unit is rotated so that each developing unit is sequentially positioned at a developing position facing the photoconductor, so that a latent image on the photoconductor is developed with each color toner. Such a rotary developing device is provided with a so-called positioning mechanism for sequentially moving each developing device to a developing position and accurately positioning the developing device. As this positioning mechanism, for example, a mechanism that uses a stepping motor to drive a rotary unit and adjusts a minute rotation angle by detecting a reference position by a sensor and controlling the number of pulses applied to the stepping motor is known.

[0003] In this type of rotary developing device, a toner cartridge as a developer container for accommodating a developer to be supplied to the developing device is attached to each developing device. The toner is supplied from the toner cartridge according to the amount of the developer. When a toner near end or a toner end occurs in a certain developing device in the rotary developing device unit and all the toner in the toner cartridge is consumed, the toner cartridge corresponding to the consumed color is filled with the toner. , The toner supply to the developing device is performed again. In addition, in this type of rotary developing device, when replenishing toner to the developing device, the rotary developing device unit is inadvertently rotated by an external force to prevent the inconvenience of toner spilling from a gap or dropping the toner cartridge. In order to do so, a so-called rotation prevention mechanism is employed.

For example, in a rotary developing device having a positioning mechanism using a stepping motor, when replenishing toner to a desired developing device, a predetermined phase of the stepping motor is excited, and the rotary developing device is driven by the static torque of the motor. An anti-rotation mechanism has been proposed in which the unit is prevented from rotating by external force (see Japanese Patent Application Laid-Open No. H10-260581). Further, as a rotation prevention mechanism, a rotation prevention mechanism is known in which a lock member is provided on a cover member which is opened when replenishing toner, and the rotary type developing unit is completely fixed by a lock member interlocked with the cover member.

[0005]

However, as described above, when the predetermined phase of the stepping motor is excited and the rotation of the rotary developing unit is prevented by the stationary torque of the motor, the main power supply is turned off. There is a problem that it does not work if it is set. Further, in the case where the rotation of the rotary developing unit is prevented by the lock member interlocking with the cover, if the rotary developing unit is rotated with an excessive force, the apparatus may be damaged.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to adopt a configuration different from the conventional anti-rotation mechanism so that when replenishing toner to the developing device, An object of the present invention is to provide an image forming apparatus capable of surely replenishing a developer while preventing a rotary developing unit from rotating carelessly.

[0007]

According to a first aspect of the present invention, there is provided an image forming apparatus comprising: a rotating type developing unit rotatably supported by an apparatus main body; In an image forming apparatus which performs development by moving a developing device to a developing position, a rotation preventing torque is generated in conjunction with a mechanical operation at the time of replenishing toner to a desired developing device, and the rotary developing device unit is actuated by an external force. A rotation preventing mechanism for preventing rotation is provided.

In the image forming apparatus according to the first aspect, when replenishing toner to a desired developing unit, the rotation preventing torque is applied to the rotary type developing unit in conjunction with a mechanical operation at the time of toner replenishment such as opening a cover. As a result, the rotary developing unit does not rotate carelessly.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the rotation preventing mechanism is fixed to a central axis of the rotary developing unit and rotates with the central axis. A shaft member which is supported by the apparatus main body in parallel with the central axis and whose rotation is regulated, and a second gear which is fitted in the shaft member and is regulated in the rotation direction of the shaft member and movable in the axial direction. And generating a rotation preventing torque when the first gear and the second gear mesh with each other.

In the image forming apparatus according to the second aspect, when replenishing toner to a desired developing device, the second gear moves in the axial direction in conjunction with a mechanical operation during toner replenishment such as opening a cover. And mesh with the first gear. Since the rotation of the second gear is restricted by the shaft member, the first gear and the second gear
When the gears mesh with each other, a rotation preventing torque is generated in the developing unit. Therefore, when the toner is supplied, the rotary developing unit does not rotate carelessly.

According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the shaft member rotates when the torque exceeds a predetermined torque.

In the image forming apparatus according to the third aspect,
Since the shaft member that rotates when the torque exceeds a certain level is used, when a large force is applied to the developing unit, the regulation of the second gear is released and the second gear can be rotated, and no rotation preventing torque is generated.

According to a fourth aspect of the present invention, in the image forming apparatus of the second aspect, the shaft member is fixed to the apparatus main body in a non-rotatable state.

In the image forming apparatus according to the fourth aspect, since the shaft member is fixed to the apparatus main body in a non-rotatable state, when a large force is applied to the developing unit, the first gear and the second gear are connected. Only the gear is damaged.

According to a fifth aspect of the present invention, in the image forming apparatus of the second aspect, the second gear moves in the axial direction of the shaft member by elastic force.

In the image forming apparatus according to the fifth aspect, when replenishing toner to a desired developing device, the second gear is resiliently driven by the second gear in conjunction with a mechanical operation during toner replenishment such as opening a cover. It is pushed up in the direction that meshes with the gear. As a result, the first gear and the second gear mesh with each other to generate a rotation preventing torque, so that the rotary developing unit does not rotate carelessly.

According to a sixth aspect of the present invention, in the image forming apparatus of the second aspect, a projection member for moving the second gear in the axial direction is attached to a cover member that is opened when toner is supplied. It is assumed that.

In the image forming apparatus according to the sixth aspect, in a normal operating state, that is, when the cover is closed, the projection member attached to the cover member pushes the second gear up to the apparatus body. From the first gear and the second gear
The gears do not mesh, and the rotary developing unit is in a rotatable state. On the other hand, when toner is supplied to a desired developing device, that is, when the cover member is open,
The protruding member attached to the cover member is not pushing the second gear. As a result, the first gear and the second gear
Since the gears mesh with each other to generate a rotation preventing torque, the rotary developing unit does not rotate carelessly.

According to a seventh aspect of the present invention, there is provided the image forming apparatus according to the first aspect, further comprising a rotation preventing mechanism releasing member which can release the rotation preventing mechanism even when a cover member which is opened when supplying toner is opened. It is characterized by being provided.

In the image forming apparatus according to the present invention, since the rotation preventing mechanism releasing member is provided, the developing device unit can be rotated as necessary even when the cover member that is opened when supplying toner is opened. Can be.

According to an eighth aspect of the present invention, in the image forming apparatus according to the second aspect, a pull-in preventing member for preventing pull-in is provided around a meshing portion where the first gear and the second gear mesh with each other. It is characterized by having.

In the image forming apparatus according to the present invention, since the pull-in preventing member for preventing the pull-in is provided around the meshing portion where the first gear and the second gear mesh, the developing unit is covered. Even when the cover member is opened, the operator's finger or the like is not drawn between the first gear and the second gear.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A color electrophotographic printer (hereinafter, referred to as a printer) as an image forming apparatus according to the present invention will be described below.
An embodiment applied to (1) will be described. First, the configuration and operation of the entire printer according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram of the entire printer. In FIG. 1, a photosensitive drum 1 as a latent image carrier is uniformly charged by a charging charger 2 as a uniform charging unit while being driven to rotate in the direction of arrow A, and then image information is obtained by a laser optical device 3. And an electrostatic latent image is formed on the surface. The laser optical device 3 includes a laser diode 3a, an fθ lens 3b, a polygon mirror 3
c. Here, the image information to be exposed is monochromatic image information obtained by decomposing a desired full-color image into yellow, cyan, magenta, and black color information. Photoconductor drum 1
The electrostatic latent image formed on the rotary developing device 4 is described later.
Are developed with yellow, cyan, magenta, and black toners, respectively, as predetermined developers, thereby forming respective color images on the photosensitive drum 1.

Each color image formed on the photosensitive drum 1 is sequentially transferred to the intermediate transfer belt 5 rotating in the direction of arrow B in FIG. 1 in synchronization with the photosensitive drum 1 for each of the single colors of yellow, cyan, magenta and black. Overprinted. The transfer onto the intermediate transfer belt 5 is performed by the photosensitive drum 1 and the intermediate transfer belt 5.
In this contact state, a predetermined bias voltage is applied to the transfer bias roller 51. The yellow, cyan, magenta, and black images superimposed on the intermediate transfer belt 5 are transferred from the double-sided copying / automatic paper feed cassette 7 or the manual paper feed tray 7a to the transfer unit via the paper feed rollers 8, 8a and the registration rollers 9 to the transfer unit. The batch transfer is performed by the secondary transfer charger 11 on the transported transfer paper 10. After the transfer, the transfer paper 10 is fixed to the toner image by the fixing device 12, and is discharged out of the apparatus as a full-color print.

The residual toner on the photosensitive drum 1 that has not been transferred onto the intermediate transfer belt 5 is removed from the photosensitive drum 1 by the photosensitive cleaner 13. Further, residual toner on the intermediate transfer belt 5 that has not been transferred onto the transfer paper 10 is removed from the intermediate transfer belt 5 by an intermediate transfer belt cleaner (not shown).

On the front side of the apparatus main body 100, a front cover 101 is provided as a door member which is attached so as to be openable and closable. The front cover 101 is opened to expose the inside of the printer during toner supply operation or maintenance. Is available.

Next, the rotary developing device 4 according to the present embodiment is described.
Will be described. FIG. 2 is a schematic configuration diagram of the rotary developing device 4. The rotary developing device 4 includes an apparatus main body 1.
00, four developing units 4K, 4Y, 4Y having substantially the same shape in the circumferential direction are provided in a developing unit 21 having a substantially cylindrical outer periphery which is rotatably mounted around a central axis 22.
M and 4C are arranged. In the illustrated example, the black developing device 4K containing the black toner and the carrier is located at the developing position facing the photosensitive drum 1, and the yellow developing device containing the yellow toner and the carrier is arranged in the counterclockwise direction in the drawing. 4Y, a magenta developing device 4M containing magenta toner and carrier, and a cyan developing device 4C containing cyan toner and carrier. Here, four developing devices 4K,
Since the internal structures of 4Y, 4M, and 4C are exactly the same, the internal structure will be described below by taking the black developing device 4K at the developing position as an example. In the drawing, the same reference numerals as those in the black developing device are attached with subscripts of Y, M, and C for distinguishing yellow, magenta, and cyan developing devices, and description thereof is omitted.

The black developing unit 4K includes a developing roller 41K as a developer carrier in a developing chamber 40K having an opening toward the photosensitive drum 1, and black toner and a carrier housed in the developing chamber. First and second stirring screws 42K for stirring a two-component developer (hereinafter, referred to as a developer);
43K. In the transport process, a part of the developer circulated and transported in the developing chamber 40K is pumped up and transported by the developing roller 41K. The developer carried and conveyed by the developing roller 41K is thinned by a developing doctor (not shown) and then conveyed to a developing area, where the electrostatic latent image on the photosensitive drum 1 is converted into a toner image in the developing area.

Of the developer in the developing device 4K, toner is consumed every time development is performed. When the decrease in the toner density is detected by, for example, a toner density sensor,
Toner is supplied from the toner cartridge 46K that stores toner to be supplied to the black developing device 4K into the black developing device 4K by a toner supply device (not shown). This allows
The toner density is kept at a predetermined density, and the image density is kept constant.

The rotary developing device 4 configured as described above
Moves each developing unit to a developing position opposite to the photosensitive drum 1 by rotation in the direction of arrow C in FIG. 2 to visualize the electrostatic latent image on the photosensitive drum 1.

By the way, during image formation, the toner cartridge 4
When the amount of toner in the toner cartridge 6 decreases and a toner near end or a toner end is detected, it is necessary to supply toner to a desired developing device. In the present embodiment, a rotation prevention mechanism that generates a rotation prevention torque in conjunction with the toner supply operation is provided so that the developer unit 21 does not rotate carelessly during toner supply. Hereinafter, the rotation preventing mechanism will be described.

FIG. 3 is a schematic front view showing the structure of the rotation preventing mechanism of the rotary developing device 4. The four toner cartridges 46 arranged in the developing unit 21 are respectively covered with the inner cover 28, but some of them are omitted in FIG. FIG. 4 is a schematic sectional view showing a normal image forming state of the rotary developing device 4. FIG. 5 shows the front cover 1 when toner is supplied to a desired developing device of the rotary developing device 4.
FIG. 11 is a schematic cross-sectional view showing a state in which 01 is opened and a rotation preventing mechanism is operating. Attached to the device body 100,
The developing unit 21 that can rotate around the central axis 22 includes:
First fixed to the central shaft 22 and rotating with the central shaft 22
A gear 23 and a shaft member 24 which is supported by the apparatus main body 100 in parallel with the central shaft 22 and rotates when a predetermined torque or more is reached.
And a second gear 26 which is fitted in the shaft member 24 and is restricted in the rotation direction of the shaft member 24 and is movable in the axial direction by a spring 25. A hollow cylindrical actuator 27 is attached to the front cover 101, which is opened at the time of toner supply, as a protrusion at a position facing the second gear 26. As the shaft member 24, a so-called free stop hinge that rotates when the torque becomes equal to or more than a predetermined torque is employed. This free stop hinge is shown in FIG.
The friction plate 24b and the leaf spring 24c are attached to the movable shaft 24a via the second gear 26 as shown in FIG.
It has a configuration caulked by d and caulking 24e.

In the normal operation state of the printer, as shown in FIG. 4, the front cover 101 is closed, and the actuator 27 engages the second gear 26 fitted to the shaft member 24 with the main assembly 1 of the apparatus.
00, the first gear 23 and the second gear 26
Are not engaged with each other, so that the rotation preventing torque is not generated in the developing unit 21. Therefore, in the rotary developing device 4, the developing unit 21 is sequentially rotatable, and each color image can be formed on the photoconductor 1.

On the other hand, when replenishing toner to a desired developing unit, as shown in FIG. 5, the front cover 101 is open and the actuator 27 does not push the second gear 26 fitted to the shaft member 24. The second gear 26 is pushed up by the spring 25 to the side opposite to the apparatus main body 100 and moves in the direction in which the second gear 26 meshes with the first gear 23. Second gear 26
Since the rotation is regulated by the shaft member 24,
When the first gear 23 and the second gear 26 mesh with each other, a rotation preventing torque is generated, and the rotation of the developing unit 21 is regulated.

Here, a free stop hinge which does not rotate below a certain torque is used for the shaft member 24. Therefore, below a certain torque, the rotation of the second gear 26 is restricted, and the rotation preventing torque acts on the developing unit 21 to restrict the rotation. Therefore, if the torque value of the shaft member 24 (free stop hinge) is set to a torque value that is considered to be generated in a normal toner supply operation, the developer unit 21 is inadvertently rotated when toner is supplied. It is possible to prevent such a problem that the data is lost. Further, when an operation of the set torque value or more is performed, the shaft member 24 (free stop hinge) is rotated, so that the developing unit 21 can be rotated and damage can be prevented.

Here, as the shaft member 24, a free stop hinge that rotates when a predetermined torque or more is used is used.
The invention is not limited to this, and a gas shock, an oil tamper, or the like that rotates when the torque exceeds a certain level can be used. From the viewpoint of miniaturization and space saving, a free stop hinge is preferably used.

By the way, as another embodiment, the shaft member 24 that rotates when the torque becomes equal to or more than a predetermined torque is attached to the apparatus body 10.
The shaft member may be completely fixed so as not to rotate to zero.
In this case, even if a large force is applied to the developing unit 21 with the front cover 101 opened, only the first gear 23 and the second gear 26 are damaged, and the entire developing unit 21 is prevented from being damaged. Can be. Further, by using the shaft member 24 as a shaft member fixed to the apparatus main body 100 so as not to rotate, the cost can be reduced.

Further, in this embodiment, FIG.
As shown in (b), a notch 28 a is provided in the inner cover 28 covering the developing unit 21, and a projection 29 is formed on a hollow cylindrical jig having substantially the same diameter as the actuator 27.
The rotation preventing mechanism releasing member 29 provided with a is provided. After inserting the protrusion 29a of the rotation preventing mechanism releasing member 29 into the notch 28a, the rotation preventing mechanism releasing member 2
By rotating 9, the rotation preventing mechanism releasing member 29 pushes the second gear 26 up to the apparatus main body 100 side. As a result, the first gear 23 and the second gear 26 do not mesh with each other, and the rotation preventing mechanism can be released. Therefore, even when the front cover 101 is opened, the developing unit 21 can be rotated, and the operation of the rotary developing device 4 can be performed during service maintenance.

Further, in this embodiment, as shown in FIG. 8, a cross section is formed so as to be close to the meshing portion where the first gear 23 and the second gear 26 mesh with each other and to prevent a finger or the like from entering the meshing portion. The pull-in prevention members 30a and 30b having a substantially triangular shape are provided. When the inner cover 28 is removed for service maintenance, the first gear 23 and the second gear 26 are exposed, but the pull-in preventing members 30a,
Since 0b is provided, even when the inner cover 28 is removed and the work is performed, the operator's finger or the like is not pulled in.

Further, in this embodiment, as shown in FIG. 9, a chamfer C is formed on the tooth tips of both surfaces where the first gear 23 and the second gear 26 mesh. By performing the chamfering C, the first gear 23 and the second gear 26 mesh with each other smoothly and reliably, and the rotation preventing mechanism works reliably.

[0041]

According to the image forming apparatus of the present invention, when toner is supplied to a desired developing device, the rotation preventing torque is applied to the developing device unit in conjunction with the mechanical operation during toner supply. Therefore, the rotation type developing unit can be prevented from being inadvertently rotated, and there is an excellent effect that toner can be reliably supplied to the developing unit. Further, according to these image forming apparatuses, since the method is not a method of generating a rotation preventing torque by exciting a predetermined phase of the stepping motor,
Even if the operator operates with the main power turned off,
There is an excellent effect that a rotation preventing torque can be generated in the rotary developing unit.

Specifically, according to the image forming apparatus of the present invention, when supplying toner to a desired developing device,
The first gear and the second gear mesh with each other in conjunction with the mechanical operation during toner replenishment, and a rotation preventing torque is generated in the developing unit. Therefore, it is possible to prevent the rotation type developing unit from being inadvertently rotated. This has an excellent effect that the toner can be reliably replenished to the developing device.

In particular, according to the image forming apparatus of the third aspect,
Since the shaft member that rotates when the torque exceeds a certain level is used, no rotation preventing torque is generated when the rotary developing unit is rotated with an excessive force. Therefore, even if the rotary type developer unit is rotated with excessive force,
There is an excellent effect of preventing the rotation prevention mechanism and the apparatus main body from being damaged.

According to the image forming apparatus of the fourth aspect,
Since the shaft member is fixed to the apparatus main body in a non-rotatable state, even if the developing unit is rotated with an excessive force, only the first gear and the second gear are damaged, thereby preventing damage to the apparatus itself. There are excellent effects that can be. Further, according to this image forming apparatus, since the fixed shaft member is used, there is an excellent effect that the cost can be reduced as compared with the shaft member of the third aspect.

According to the image forming apparatus of the present invention, the developing device unit can be rotated by using the anti-rotation mechanism releasing member as needed even when the cover member opened when supplying toner is opened. Therefore, there is an excellent effect that service maintenance can be improved.

According to the image forming apparatus of the present invention, since the pull-in preventing member is provided, even if the cover member for covering the developing unit is opened, the first gear and the second gear can be connected.
Workers' fingers etc. are not drawn in between the gears,
There is an excellent effect that safety can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a printer according to an embodiment.

FIG. 2 is a schematic configuration diagram showing an internal configuration of a rotary developing device of the printer.

FIG. 3 is a schematic front view showing a configuration of a rotation preventing mechanism of the rotary developing device.

FIG. 4 is a schematic sectional view showing a normal image forming state of the rotary developing device.

FIG. 5 is a schematic cross-sectional view showing a state in which a rotation preventing mechanism of the rotary developing device is acting.

FIG. 6 is a schematic sectional view showing a configuration of a free stop hinge of the rotation preventing mechanism.

FIG. 7A is a schematic cross-sectional view illustrating a state in which a rotation preventing mechanism releasing member is inserted into the rotary developing device. (B)
FIG. 3 is a schematic top view showing a state in which a rotation preventing mechanism releasing member is inserted into the rotary developing device.

FIG. 8 is a front view showing a state where a pull-in preventing member is attached to the rotary developing device.

FIG. 9 is a top view showing a state of a tooth tip on both surfaces of the rotation preventing mechanism where a first gear and a second gear mesh with each other.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 photoreceptor drum 4 rotary developing device 21 developing unit 22 central shaft 23 first gear 24 shaft member 25 spring 26 second gear 27 actuator 28 inner cover 29 rotation preventing mechanism release member 100 main body 101 front cover

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H030 AD01 AD16 BB02 BB24 BB33 BB36 BB38 2H071 BA03 BA14 BA16 CA05 CA07 CA09 DA08 DA15 DA26 EA02 EA06 2H077 AA03 AA15 AA35 AB02 AB14 AB18 AC02 AD02 AD06 AD13 BA02 DA03 DA01 DA16 EA24 GA13

Claims (8)

[Claims] An image forming apparatus for performing development by moving a desired developing device to a developing position by rotating a rotary developing device unit rotatably supported by an apparatus main body. An image forming apparatus, comprising: a rotation preventing mechanism that generates a rotation preventing torque in conjunction with a mechanical operation at the time of replenishing toner and that prevents the rotary developing unit from rotating by an external force. apparatus. 2. An image forming apparatus according to claim 1, wherein said rotation preventing mechanism is fixed to a central axis of said rotary developing unit and rotates with said central axis, said first gear being parallel to said central axis. A shaft member rotatably supported by the main body of the apparatus, the rotation of which is regulated, and a second gear which is fitted into the shaft member, is regulated in the rotation direction of the shaft member, and is movable in the axial direction. An image forming apparatus, wherein a rotation preventing torque is generated when one gear and the second gear mesh with each other. 3. The image forming apparatus according to claim 2, wherein the shaft member rotates when the torque exceeds a predetermined value. 4. The image forming apparatus according to claim 2, wherein the shaft member is fixed to the apparatus main body in a non-rotatable state. 5. The image forming apparatus according to claim 2, wherein the second gear moves in the axial direction of the shaft member by elastic force. 6. An image forming apparatus according to claim 2, wherein a projection member for moving said second gear in the axial direction is attached to a cover member opened when toner is supplied. 7. The image forming apparatus according to claim 1, further comprising a rotation preventing mechanism releasing member that can release the rotation preventing mechanism even when a cover member that is opened when supplying toner is opened. Image forming apparatus. 8. The image forming apparatus according to claim 2, wherein the first gear and the second gear mesh around a meshing portion where the first gear meshes with the second gear.
An image forming apparatus, comprising a pull-in preventing member for preventing pull-in.