JP5285986B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that adjusts the rotational speed of a photosensitive drum.

This type of image forming apparatus has a photosensitive drum, and toner is supplied to the surface of the drum from a developing device to develop a toner image. Then, this toner image is transferred indirectly to a sheet via a transfer belt, or directly transferred to a sheet conveyed on the transfer belt.
Here, a technique is known in which the drum is driven by a motor, and its rotational speed is detected and controlled by a sensor (see, for example, Patent Document 1).

JP 2005-91400 A

  By the way, in the above-described prior art, the sensor and the control board are electrically connected, and the driving power is supplied to the sensor. However, when the board is disposed at a position away from the sensor. However, there is a problem that the wiring for connecting the sensor and the substrate becomes long, which is disadvantageous in terms of productivity and cost of the image forming apparatus. This is because the wiring is easily caught around and a long wire is required.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus that solves the above-described problems and requires a short wiring for connecting a sensor and a control board.

  A first invention for achieving the above object has a photosensitive drum and a motor for driving the drum, and also has a sensor for controlling the rotational speed of the motor. The drum drive unit to be formed on the outside, the control board for supplying the drive power to the sensor, and the drive unit are mounted on the outside of the drum drive unit, relaying the wiring from the sensor, And a relay board connected to the control board together with the wiring.

According to the first invention, the sensor and the control board are not directly connected via the wiring, and the wiring from the sensor is connected to the relay board mounted on the drive unit. Therefore, the wiring for connecting the sensor and the control board can be shortened as compared with the conventional case.
Further, since the wiring from the relay board is integrally processed with the wiring from the motor and connected to the control board, the drum drive unit can be easily stored, and the assembly can be easily performed. This is advantageous in terms of cost.

A second invention is characterized in that, in the configuration of the first invention, the relay board is contained within the range of the outer shape of the drive unit.
According to the second invention, in addition to the operation of the first invention, the outer dimension of the relay board is not made larger than the outer dimension of the drive unit, so that the breakage of the relay board can be avoided.

According to a third invention, in the configuration of the first or second invention, the drive unit has a holding portion that holds a wiring from the sensor to the relay substrate.
According to the third invention, in addition to the effects of the first and second inventions, the drum driving unit is further provided with the holding portion, and the wire processing from the sensor to the relay board is performed. The unit fits even better.

According to a fourth aspect of the present invention, in the configuration of the first to third aspects, the drum drive unit has a unit casing that rotatably supports the drive shaft of the drum, and the control board is It is attached from the outside so as to cover a part thereof.
According to the fourth invention, in addition to the operation of the first to third inventions, a drum drive unit having a motor and a sensor is used, but the control board is separated from the motor, and the unit housing Since it is attached so as to cover a part thereof from the outside, it contributes to miniaturization of the drum drive unit itself, and the degree of freedom of layout of this drive unit is increased.

  According to the present invention, it is possible to provide an image forming apparatus in which a relay board is provided in the drive unit and the wiring for connecting the sensor and the control board is shortened.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of the tandem color printer according to the present embodiment as viewed from the front, and the right and left directions in FIG.
As shown in the figure, a sheet cassette 3 is disposed at the bottom of the apparatus body 2, and sheets P before image formation are accommodated in the cassette 3 in a stacked state. Are separated one by one through the cassette 3 and sent out from the cassette 3 toward the left in FIG.

  The paper P delivered from the cassette 3 is conveyed upward along the left side surface of the main body 2. Inside the main body 2, a feed roller 22, a registration roller 24, an image forming unit 4, and a transfer unit 71 are sequentially arranged on the downstream side in the sheet conveyance direction. An exposure unit 20 is provided below the image forming unit 4, and laser light is irradiated from the unit 20 toward the photosensitive drum 5 of the image forming unit 4.

In addition, a fixing unit 72 and a discharge branching unit 74 are sequentially arranged on the downstream side of the transfer unit 71 as viewed in the paper transport direction. In the case of single-sided printing, the paper P discharged from the fixing unit 72 is discharged from the discharge branching unit. The sheet is discharged to the sheet discharge tray 76 through 74.
On the other hand, a duplex printing unit 78 is disposed between the discharge branching unit 74 and the cassette 3. In this unit 78, the sheet P discharged from the fixing unit 72 is returned to the registration roller 24, and the image forming unit 4. Send again towards

  Here, the image forming unit 4 according to the present exemplary embodiment includes four image forming units 4a, 4b, 4c, and 4d. These units 4a to 4d are arranged in order from the front side to the back side of the printer 1, and are provided corresponding to images of four different colors (yellow, magenta, cyan and black), and are respectively charged and exposed. The yellow, magenta, cyan and black images are sequentially formed through the development and transfer processes.

  Specifically, each of the units 4a to 4d is provided with drums 5a, 5b, 5c, and 5d that carry visible images (toner images) of the corresponding colors. The drums 5a to 5d are connected to the drum drive units 26Y, 26M, 26C, and 26B of FIG. 2 when the back side of FIG. It is rotatably installed and is driven counterclockwise in FIG. 1 by each drive motor 32 in FIG.

  Returning to FIG. 1 again, the appropriate chargers 6a, 6b, 6c, 6d, developing units 7a, 7b, 7c, 7d, and rubbing rollers 8a, 8b, 8c are located at appropriate positions around the drums 5a-5d. , 8d and intermediate transfer rollers 9a, 9b, 9c, 9d.

  In the chargers 6a to 6d, the surfaces of the color drums 5a to 5c and the black drum 5d are uniformly charged. In the developing units 7a to 7d, yellow, magenta, cyan, and black toners are supplied via a toner container and a hopper (not shown), and electrostatically applied to the surfaces of the drums 5a to 5d using the toner. Adhere to.

  Thereby, toner images corresponding to the electrostatic latent images by the exposure unit 20 are developed on the surfaces of the drums 5a to 5d. In this embodiment, the toner images formed on the drums 5a to 5d are sequentially transferred onto the transfer belt 10 and synthesized as a toner image for one page.

  Specifically, the belt 10 is an endless belt in which both end portions of a dielectric resin sheet material are overlapped and joined, or a seamless belt without a seam, and includes a driving roller 12 and a conveying roller 11. It is hung around. And it drive | works clockwise of the figure with the drive motor which is not shown in figure arrange | positioned in the vicinity of this drive roller 12.

The belt 10 travels between the drums 5a to 5d and the intermediate transfer rollers 9a to 9d, whereby the toner images formed on the drums 5a to 5d are primarily transferred onto the belt 10. Then, the rubbing rollers 8a to 8d remove the toner remaining on the drums 5a to 5d, respectively.
The transfer unit 71 described above is provided adjacent to the driving roller 12, and when the paper P passes between the roller of the transfer unit 71 and the belt 10, the toner image transferred onto the belt 10 is secondary to the paper P. The paper P is transferred and conveyed toward the fixing unit 72.

By the way, the drum drive units 26Y, 26M, 26C, and 26B described above drive the corresponding drums 5a to 5d separately.
Specifically, as shown in FIG. 2, each of these units 26Y, 26M, 26C, and 26B is disposed in a unit housing 80, and this housing 80 is screwed to the main body 2 via a connecting portion 82 or the like. ing.

  The housing 80 has a gear case (not shown), and a gear train is disposed in the case. On the other hand, in the vicinity of the case, drum drive shafts 44 extending from the drive units 26Y, 26M, 26C, and 26B are respectively installed through the housings 80 (FIG. 4). The unit casing 27 is rotatably supported, and is driven as each driving motor 32 described above rotates.

  Further, around each drive shaft 44, the drive shafts of the corresponding developing devices 7 a to 7 d and the corresponding drive shafts of the rubbing rollers 8 a to 8 d are rotatably supported by the housing 80. The color drive shafts mesh with the gear train in the case, and the drive force of a color dedicated motor (not shown) is transmitted and driven. On the other hand, each drive shaft for black is driven by the drive force of a dedicated motor for black (not shown).

Incidentally, a brushless motor is used for each drive motor 32 described above. Specifically, as shown in FIG. 3, each of the drive units 26Y, 26M, 26C, and 26B has a plate-like unit housing 27, and a brushless motor 32 is disposed together with a speed reducer at a substantially central portion thereof. Has been.
Here, each drive unit 26Y, 26M, 26C, 26B of the present embodiment is configured to be able to measure the rotational speed of each motor 32.

  Specifically, one drum drive unit among the drive units 26Y, 26M, 26C, and 26B shown in FIG. 3 will be described as an example. As shown in FIGS. 4 to 7, the unit housing of the drive unit 26 is shown. 27 includes a resin case 28 that bulges toward the housing 80, and a drum drive shaft 44 extends from the case 28.

Further, an encoder 36 and sensors 38 and 39 for controlling the rotational speed of the motor 32 are disposed around the drum drive shaft 44 (FIG. 5).
On the other hand, the unit housing 27 includes a sheet metal lid 30 on the back side of the case 28. Further, in this embodiment, the relay board 46 is mounted on the sheet metal lid 30, and the motor 32 is housed via the relay board 46. 27 (FIG. 4).

The relay board 46 is formed in a size that does not protrude from the outer shape of the sheet metal lid 30, and a wiring connector 47 is disposed at an appropriate position at the lower end portion of the relay board 46. 49 are provided.
Specifically, the relay connector 48 is connected to the wiring 40 from the sensor 38 (FIGS. 4 and 6). The wiring 40 is pulled out from the inside of the cover 34 and is vertically moved by the side surface of the resin case 28. Four guides (holding portions) 29 formed along the direction extend so as to sew, and are connected to the connector 48 from the lower side of the relay board 46.

Further, the relay connector 49 is connected to the wiring 41 from the sensor 39 (FIGS. 5 and 7), that is, the wiring 41 is also drawn out from the inside of the cover 34 and formed on the side surface of the resin case 28. It extends by engaging with one guide 29 and saddle 83 and is connected to the connector 49 from the left side of the relay board 46.
On the other hand, a control board 50 that supplies driving power (for example, 5 V) to the sensors 38 and 39 is disposed at an appropriate position of the housing 80, for example, above each motor 32. The substrate 50 of the present embodiment also has a motor drive control function, and controls the drive of each motor 32 by counting the pulse signals fed back from the encoder 36, and is independent of each motor 32. It is formed (FIG. 2).

Specifically, the substrate 50 extends along the back surface of the printer 1 and is provided so as to cover a part of the unit housing 27 from the outside over the drive units 26Y, 26M, 26C, and 26B. It is installed in the vicinity of each motor 32.
A power supply circuit and an IC chip (not shown) are mounted on the substrate 50, and the drive control of the motors 32 for driving the drums 5a to 5d and the motors for driving the belt 10 are integrated on the substrate 50.

The relay board 46 that relays the wirings 40 and 41 from the sensors 38 and 39 consolidates the wiring from the motor 32 and the wirings 40 and 41 from the sensors 38 and 39 into one wiring, and connects the wiring connector 47. To the substrate 50.
Thereby, the IC chip and the motors 32 of the drums 5a to 5d and the motor of the belt 10 are electrically connected, and the drive control of the drums 5a to 5d and the belt 10 can be performed.

  In the printer 1 described above, the paper P is separated and sent from the cassette 3 one by one, and the paper P reaches the registration roller 24. The roller 24 sends the paper P to the transfer unit 71 while correcting the oblique feeding of the paper P and measuring the timing with the toner image formed by the image forming unit 4.

  Further, based on image data from a controller (not shown), the printer 1 controls the irradiation of the laser beam by the exposure unit 20. As a result, an electrostatic latent image of the original image is created on each of the drums 5 a to 5 d in the image forming unit 4, and then a toner image is formed on each of the drums 5 a to 5 d from the latent image and transferred to the transfer belt 10. Synthesized. Subsequently, the toner image transferred and synthesized on the belt 10 is transferred to the paper P by the transfer unit 71.

Thereafter, the paper P is fed toward the fixing unit 72 while carrying an unfixed toner image. Next, the paper P discharged from the fixing unit 72 is discharged to the tray 76 through the discharge branching unit 74.
When double-sided printing is performed in contrast to this single-sided printing, the paper P discharged from the fixing unit 72 is pulled back to the unit 78 side by the discharge branching unit 74, and this paper P passes through the registration roller 24 and is again transferred to the transfer unit. Sent to 71. In this case, the toner image is transferred to the surface of the paper P that has not been printed.

  As described above, according to the present embodiment, the sensors 38 and 39 and the control board 50 outside the drive unit 26 are not directly connected via the wiring, and the wiring from the sensors 38 and 39 is connected to the drive unit. 26 is connected to a relay board 46 mounted on the H.26. Therefore, the wiring for connecting the sensors 38 and 39 and the substrate 50 can be shortened as compared with the conventional case where the sensor and the substrate are directly connected.

Further, since the wiring from the relay board 46 is integrally processed with the wiring from the motor 32 and connected to the board 50, the drum drive unit 26 can be easily accommodated, and the assembly can be easily performed. This is advantageous in terms of performance and cost.
Further, since the outer dimension of the relay board 46 is not made larger than the outer dimension of the drive unit 26, specifically, the unit casing 27, the relay board 46 does not protrude from the casing 27, and damage to the relay board 46 is avoided. It becomes possible.

Furthermore, since the guide 29 is formed on the side surface of the unit casing 27, more specifically, the resin case 28, and the wire rod processing from the sensors 38 and 39 to the relay substrate 46 is performed, the drum drive unit 26 is accommodated. It gets even better.
Further, although four drum drive units 26 having a motor 32 and sensors 38 and 39 are used, the substrate 50 that also serves as a drive control function is not mounted on the motor 32 and is separated from the motor 32. Since the unit casing 27 is attached so as to cover a part from the outside, it contributes to downsizing of the drive unit 26 itself, and the degree of freedom of layout of the drive unit 26 is increased.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the claims.
For example, the number of photosensitive drums of the present invention is not limited to four, and the toner image on this drum is transferred directly to the paper conveyed on the belt in addition to being indirectly transferred to the paper via the belt. May be.

  Further, in the above embodiment, an example in which the image forming apparatus is embodied in a printer is shown. However, the image forming apparatus of the present invention is naturally applicable to a multifunction machine, a copier, a facsimile machine, and the like.

1 is a schematic configuration diagram of an image forming apparatus of an embodiment. It is the perspective view which looked at the inside of the device of Drawing 1 from the back. FIG. 3 is a perspective view of each drum drive unit with a drive control board removed from FIG. 2. It is the perspective view which showed one drum drive unit of FIG. 3, and was seen from the left side surface of the apparatus. It is the perspective view which looked at FIG. 4 from the front of the apparatus. FIG. 5 is a perspective view including wiring from a sensor in FIG. 4. It is the perspective view which looked at FIG. 6 from the right side surface of the apparatus.

Explanation of symbols

1 Printer (image forming device)
5 Photosensitive drum 26 Drum drive unit 27 Unit housing 29 Guide (holding part)
32 Motor 38, 39 Sensor 40, 41 Wiring 46 Relay board 50 Control board

Claims (4)

A photosensitive drum;
A drum driving unit having a motor for driving the drum and a sensor for controlling the rotational speed of the motor, and for forming a toner image on the drum by the driving;
A control board disposed outside the drum drive unit and supplying the sensor with drive power;
It is mounted on the drive unit, includes a relay board that relays the wiring from the sensor and connects to the control board together with the wiring from the motor ,
The control board is
An image forming apparatus , wherein a plurality of the relay boards are connected . The image forming apparatus according to claim 1,
The image forming apparatus according to claim 1, wherein the relay substrate is contained within a range of an outer shape of the drive unit. The image forming apparatus according to claim 1, wherein
The image forming apparatus according to claim 1, wherein the driving unit includes a holding unit that holds wiring from the sensor to the relay substrate. The image forming apparatus according to any one of claims 1 to 3,
The drum drive unit has a unit housing that rotatably supports the drive shaft of the drum,
The image forming apparatus, wherein the control board is attached to the unit housing from the outside so as to cover a part thereof.

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