JP3511713B2 - Electrophotographic equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus which develops an electrostatic latent image formed on a photosensitive member with toner, transfers the toner image onto a sheet and discharges it.

[0002]

2. Description of the Related Art Recently, in a transfer type color electrophotographic apparatus,
A method has been used in which color toner images of different colors are sequentially formed on an electrostatic carrier such as a photoconductor and the color toner images of the respective colors are multiple-transferred onto a transfer body.

For example, in JP-A-55-90972, as a transfer method, yellow, cyan and magenta color toner images formed on an image bearing member such as a photosensitive drum or an insulating drum are intermediate image bearing members. Alternatively, a method has been proposed in which the color toner images of the three colors formed on the intermediate image bearing member are collectively transferred to the transferring member by transferring the toner images on the belt in an overlapping manner.

FIG. 3 is a schematic diagram of a conventional color electrophotographic apparatus. Hereinafter, a conventional color electrophotographic apparatus will be described with reference to FIG.

In FIG. 3, a process unit 80 is detachably provided in the main body 71 of the electrophotographic apparatus.
The process unit 80 includes a photoconductor (photoconductor belt).
51 and the intermediate transfer belt portion are integrated. The photoconductor 51 is supported by support rollers 77a, 77b, 77c. The support roller 77a is biased by a spring 81.

A charger 52 for charging the photoconductor 51 is provided in the vicinity of the photoconductor 51. Process unit 8
An optical system 53 is arranged above 0. Optical system 53
Exposes the surface of the charged photoconductor 51 with a light beam corresponding to image data. Further, developing units 54a, 54b, 54c, 54d are arranged on the side of the process unit 80. These developing devices 54a, 54b, 54c,
54d develops the electrostatic latent image formed on the photoconductor 51 with cyan, magenta, yellow, and black color toners, respectively. Developing devices 54a, 54b, 54c, 54
d is brought into contact with and separated from the photoconductor 51 by cams 75a, 75b, 75c and 75d, respectively.

In the process unit 80, there is provided an intermediate transfer body belt 55 which sequentially superimposes the developed color toner images on the photosensitive body 51. The intermediate transfer belt 55 is supported by support rollers 78a, 78b, 78c. The first transfer device 56 transfers the color toner image on the photoconductor 51 to the intermediate transfer belt 55. The first cleaning device 57 removes the residual toner after the transfer of the photoconductor 51. Further, the static eliminator 58 initializes the potential of the photoconductor 51.

A position marker 7 is provided on the intermediate transfer belt 55.
4 are provided. The position detector 73 detects the position of the intermediate transfer belt 55 based on the position marker 74. Below the process unit 80, a paper cassette 68 that stores paper 69 is mounted. Paper cassette 6
The paper 69 in 8 is transported by the transport system 70.

The second transfer device 59 is an intermediate transfer belt 5.
The color toner image of No. 5 is transferred onto the sheet 69 conveyed by the conveying system 70. The second cleaning device 60 removes the residual toner on the intermediate transfer belt 55. The second cleaning device 60 is provided with a blade 61. The blade 61 is held by a holding member 62 having a shaft 63, and is brought into contact with and separated from the intermediate transfer belt 55 by a cam 64 provided in the electrophotographic apparatus main body 71. Drive source 66
Rotates the shaft 65 of the cam 64.

The fixing device 67 fixes the color toner image transferred on the paper 69. The paper 69 fixed by the fixing device 67 is ejected to the paper ejection tray 79.

Next, the operation of the above-mentioned conventional electrophotographic apparatus will be described. First, when a print start instruction is given to the electrophotographic apparatus main body 71, the photoconductor 51 starts rotating in the direction of arrow A. The surface of the rotating photoconductor 51 has a charger 52.
Are uniformly charged by. The surface of the charged photoconductor 51 is optically scanned by the optical system 53. Since the photoconductor 51 has an insulating property in a dark portion and has a property of removing the electric charges charged only in the light-irradiated portion, light irradiation corresponding to image data is performed on the charged photoconductor 51. For example, an electrostatic latent image of an image can be formed on the surface.

The electrostatic latent image formed on the photosensitive member 51 has developing units 54a and 54 having toners of designated colors.
b, 54c, 54d develop as a color toner image. The developing devices 54a, 54b, 54c, 54d are brought into contact with the photoconductor 51 by the cams 75a, 75b, 75c, 75d rotating half a turn, and when the development is completed, the cams 75a, 75b, 75c, 75d rotate half a turn again. Then, it is separated from the photoconductor 51.

The developed color toner image on the photoconductor 51 is transferred to the intermediate transfer belt 55 by the first transfer device 56. The residual toner on the surface of the photoconductor 51 after the transfer is removed by the first cleaning device 57, and the charge on the surface of the photoconductor 51 is initialized by the static eliminator 58. After this,
The photoconductor 51 is charged again by the charger 52, and images can be continuously formed by repeating the image forming process described above.

The cyan, magenta, yellow, and black monochromatic color toner images formed on the photoconductor 51 are sequentially transferred to the intermediate transfer belt 55 by the first transfer device 56, and all the color toner images are intermediately transferred. When superposed on the body belt 55, the second transfer device 59 collectively transfers the superposed color toner images onto the sheet 69 to be conveyed.

After the color toner images on the intermediate transfer belt 55 are collectively transferred onto the paper 69, the cam 64 is rotated by the rotation of the shaft 65, and the blade 61 provided in the second cleaning device 60 causes the intermediate transfer belt 55 to move. Abutted against. The contact of the blade 61 removes the residual toner on the intermediate transfer belt 55, and prepares for the transfer of the color toner image formed on the photoconductor 51 next.

After cleaning the intermediate transfer belt 55 for a specified length, the blade 61 is separated from the surface of the intermediate transfer belt 55 by the rotation of the cam 64, so that the toner image can be held again. The paper 69 to which the color toner image has been transferred is guided to the fixing device 67 and fixed.
The fixed paper 69 is discharged face-up on the paper discharge tray 79.
Is discharged to.

When the process unit 80 reaches the end of its life,
The old process unit 80 is an electrophotographic apparatus main body 71.
And is replaced with a new process unit 80. Thereby, the operability is enhanced. Further, when the paper 69 is jammed in the main body 71 of the electrophotographic apparatus, the jam of the paper 69 is facilitated by pulling out the process unit 80. As described above, an electrophotographic apparatus that outputs a high quality color image and that has good operability is provided.

[0018]

However, in the above-mentioned conventional electrophotographic apparatus, the paper can be discharged only by face-up. In order to discharge the paper face down, it is necessary to further provide a carrying system for carrying the paper to the upper part of the electrophotographic apparatus main body 71.

If the power supply to the main body 71 of the electrophotographic apparatus is cut off for some reason during printing, the user sets the process unit 80 while the developing devices 54a to 54d are in contact with the photoconductor 51. When the action of detaching is performed, the photoconductor 51 of the process unit 80 is moved to the developing device 54a.
Trailed to ~ 54d. As a result, the photoconductor 5
There is a problem in that the photoconductor 51 and the developing devices 54a to 54d are damaged by rubbing between the developing roller of the developing device 54a to 54d and the developing roller.

The present invention solves the above-mentioned problems of the prior art. Paper can be discharged face-up and face-down, and the photoconductor and the developing device may be damaged when the process unit is attached or detached. It is an object of the present invention to provide a protected electrophotographic device.

[0021]

An electrophotographic apparatus according to a first aspect of the present invention is an electrophotographic apparatus including a photoconductor provided in a main body of the apparatus and a developing device for developing an electrostatic latent image on the photoconductor. A first unit that integrates a contact / separation mechanism for contacting and separating the developing device with the photoconductor and a switchback mechanism for switching back and discharging the sheet on which the toner image has been transferred and fixed , The first unit is the device body
It can be opened and closed freely in the opening of the
Is mounted on the main body of the device .

[0022]

An electrophotographic apparatus according to a third invention is the same as the electrophotographic apparatus according to the first invention, except that the photoconductor is the second one.
Removably provided as a unit in the apparatus main body, the second
This unit is not removable when the first unit is closed.
It is detachable when it is stopped and the first unit is opened .

[0024]

[0025]

In the electrophotographic apparatus according to the first and second aspects of the present invention, the developing unit is brought into and out of contact with the photosensitive member by the first unit which is formed by integrating the contact and contact mechanism and the switchback mechanism. It is possible to eject paper face down. Further, since the contact / separation mechanism and the switchback mechanism are unitized as the first unit, the handling in assembly of the device becomes easy. Furthermore
In addition, the developing device can be attached to the main body of the device through the opening.
As a result, the mounting of the developing device becomes easy.

[0026]

[0027]

[0028] In the electrophotographic apparatus according to the second invention, in conjunction with opening and closing of the first unit, attachment and detachment of the second unit is prevented when closing the first unit, open the first unit Since the second unit can be attached and detached when the developing device is in contact with the photoconductor, the removal of the second unit is blocked when the developing device is in contact with the photoconductor, and the developing device is separated from the photoconductor. Sometimes it is possible to remove the second unit.
Therefore, the user is prevented from removing the second unit while the developing device is still in contact with the photoconductor, and the photoconductor and the developing device are prevented from being damaged when the second unit is detached from the apparatus main body. .

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an electrophotographic apparatus according to an embodiment of the present invention.

In FIG. 1, the process unit 12 is detachably provided in the main body 21 of the electrophotographic apparatus. The process unit 12 includes at least the photoconductor belt 1, the intermediate transfer belt 7, the first cleaning device 10, and the second cleaning device 11 integrated with each other.

The photosensitive belt 1 is supported by a supporting roller 8. Close to the photoconductor belt 1, the photoconductor belt 1
A charging device 2 for uniformly charging the battery is provided. An optical exposure system 3 that forms an electrostatic latent image on the photosensitive belt 1 is arranged above the process unit 12. Further, on the side of the process unit 12, developing devices 4a, 4b, 4c, 4 for developing the electrostatic latent image formed on the photosensitive belt 1 are provided.
d is attached.

The intermediate transfer belt 7 is supported by a supporting roller 9. The first transfer device 6 transfers the developed color toner image on the photosensitive belt 1 to the intermediate transfer belt 7. The first cleaning device 10 cleans the photosensitive belt 1 after transfer.

Below the process unit 12, the paper 1
A paper cassette 14 for storing 5 is attached. Second
The transfer device 13 collectively transfers the color toner images of the respective colors superposed on the intermediate transfer belt 7 onto the paper 15 conveyed from the paper cassette 14. Second cleaning device 11
Cleans the intermediate transfer belt 7 after the batch transfer. The fixing device 16 fixes the color toner image transferred on the paper 15.

In the electrophotographic apparatus of this embodiment, the side unit 25 is provided beside the developing devices 4a, 4b, 4c and 4d.
Is provided. The side unit 25 is formed by integrating the contact / separation mechanism unit 5 and the switchback mechanism unit 30. The separating / contacting mechanism section 5 includes developing units 4a, 4b, 4 respectively.
A cam 5 for bringing the c and 4d into and out of contact with the photosensitive belt 1.
It consists of a, 5b, 5c and 5d. The switchback mechanism unit 30 includes a paper discharge roller 17, a paper conveyance change tab 18, a sensor 19 for confirming the conveyance of the paper, and a switchback conveyance path 27. The paper is ejected face down onto the paper ejection tray 20. Switch back. The side unit 25 is attached to the opening of the electrophotographic apparatus main body 21 so as to be openable and closable around the rotation shaft 26.

A lock mechanism 31 for preventing the process unit 12 from being pulled out is provided above the developing device 4a. The lock mechanism 31 includes a shaft 22, a guide 23, and a spring 24. The shaft 22 is guided by a guide 23 so as to be movable in the contact / separation direction with respect to the photosensitive belt 1, and is biased by a spring 24 in the direction of arrow B.

Next, the operation of the electrophotographic apparatus in this embodiment will be described. Since the operation related to image formation is the same as that of the conventional example, the operation related to the side unit 25 and the lock mechanism 31 will be described here.

As described above, in the electrophotographic apparatus of this embodiment, the contact / separation mechanism 5 for contacting / separating the developing devices 4a, 4b, 4c, 4d with the photosensitive belt 1 and the paper 15 are discharged face down. In order to do so, a switchback mechanism section 30 for switching back the paper 15 is incorporated as a side unit 25.

When the paper 15 is discharged face-up, the paper 15 that has passed through the fixing device 16 is directly discharged to the paper discharge tray 20 by the paper-conveyance changing claw 18.
When the paper is discharged face down, the paper discharge roller 17 rotates in a predetermined direction, and the paper 15 that has passed through the fixing device 16 has the paper conveyance changing claw 18 and the paper discharge roller 17.
Is sent to the switchback transport path 27. When the sensor 19 detects the trailing edge of the paper 15, the paper discharge roller 17
Rotates in the reverse direction, and the paper 15 is ejected from the switchback conveyance path 27 to the paper ejection tray 20.

In this way, the paper 15 can be discharged to the paper discharge tray 20 by selecting face-up or face-down. In the electrophotographic apparatus of this embodiment, since the contact / separation mechanism section 5 and the switchback mechanism section 30 are configured as one side unit 25, handling at the time of assembly is easy and the number of parts can be reduced.

FIG. 2 is a schematic diagram showing a state in which the side unit 25 of the electrophotographic apparatus in the embodiment of the present invention is opened.

As shown in FIG. 2, the side unit 25
Can be opened with respect to the electrophotographic apparatus main body 21 about the rotation shaft 26. By using the openings formed at this time, it is possible to mount the developing devices 4a to 4d and perform jam processing for the sheet 15 after fixing.

When the side unit 25 is opened, the shaft 22 is moved in the direction of arrow B by the spring 24. Thereby, the lock of the process unit 12 is released, and the process unit 12 can be pulled out to the front. Conversely, when the side unit 25 is closed as shown in FIG.
The end of 2 resists the spring 24 and the process unit 1
Pushed to the side of 2, the shaft 22 moves along the guide 23 toward the process unit 12. As a result, the process unit 12 is locked by the shaft 22,
The withdrawal of the process unit 12 is blocked.

By such a lock mechanism 31, when the power supplied to the electrophotographic apparatus is cut off for some reason during printing, the developing devices 4a to 4d are erroneously kept in contact with the photosensitive belt 1. This prevents the process unit 12 from being pulled out from the electrophotographic apparatus main body 21. Therefore, it is possible to prevent damage due to rubbing between the photosensitive belt 1 and the developing rollers of the developing devices 4a to 4d.

[0044]

As described above, according to the present invention, the paper can be discharged face-up and face-down, the handling at the time of assembly is easy, and the second unit including the photoconductor is detached. It is possible to obtain an electrophotographic apparatus capable of stably outputting a high-quality image in which damage to the photoconductor and the developing device is prevented.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an electrophotographic apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an electrophotographic apparatus according to an embodiment of the present invention with a side unit open.

FIG. 3 is a schematic configuration diagram of a conventional color electrophotographic apparatus.

[Explanation of symbols]

1 photoconductor belt 2 charger 3 light exposure system 4a, 4b, 4c, 4d developing device 5 Contact and separation mechanism 5a, 5b, 5c, 5d cams 6 First transfer device 7 Intermediate transfer belt 8 Support rollers 9 Support roller 10 First cleaning device 11 Second cleaning device 12 process units 13 Second transfer device 14 paper cassettes 15 sheets 16 Fixing device 17 Paper discharge rollers 18 Paper transport change tab 19 sensors 20 Output tray 21 Electrophotographic device body 22 shaft 23 Guide 24 spring 25 side unit 26 rotation axis 27 Switchback transport path 30 Switchback mechanism 31 Lock mechanism

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI G03G 21/00 354 (72) Inventor Yoshiaki Ijima 1006 Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Nobuo Kishiyama 1006 Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Masayoshi Kondo, 1006 Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-6-208269 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 15/00

Claims (2)

(57) [Claims] 1. An electrophotographic apparatus comprising a photoconductor provided in a main body of the apparatus and a developing device for developing an electrostatic latent image on the photoconductor, wherein the developing device is brought into contact with and separated from the photoconductor. A first unit is provided which is integrated with a contact / separation mechanism and a switchback mechanism for switching back and discharging the sheet on which the toner image is transferred and fixed .
The unit is installed in the opening of the device body so that it can be freely opened and closed.
The developing device is attached to the main body of the apparatus through the opening.
An electrophotographic device characterized by being worn . 2. The photosensitive member is detachably attached to the apparatus main body as a second unit, and the second unit is a front unit.
Note When the first unit is closed
The electrophotographic apparatus according to claim 1 , wherein the electrophotographic apparatus is detachable when the first unit is opened .