JP2007284192A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accomplish reduction of action sound by suppressing vibration of a pick roller in an image forming device. <P>SOLUTION: A pick roller housing 23 is constituted by a housing body part 30; a bearing part 31 for supporting a shaft member; and a reinforcement rib 32 for reinforcing bonding of the bearing part 31 and the housing body part 30. The eight reinforcement ribs 32 are formed so as to be radially spaced from the bearing part 31 with an angle of approximately 45°. Among them, the reinforcement rib 32a is arranged in a direction that recording paper is advanced from a paper feed tray 9 to a picking area by the pick roller 21, The reinforcement rib 32b is arranged in a direction that the pick roller 21 is pressed by a separation pad 24, and the reinforcement rib 32c is arranged in a direction that the recording paper is fed out from the picking area by the pick roller 21. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a printer that forms an image on recording paper.

  2. Description of the Related Art Conventionally, an image forming apparatus is provided with a recording paper transport mechanism that transports recording paper held in a paper feed tray to an image forming unit. As an example of a conventional recording paper transport mechanism, for example, a pick roller that feeds the uppermost recording paper held in a paper feed tray, a pick roller housing that rotatably supports the pick roller, and a pick roller Some of them are configured by a separation pad or the like that presses the sent recording paper against a pick roller and separates it from other recording paper held in a paper feed tray.

Patent Document 1 discloses an image forming apparatus including a feed roller that conveys recording paper delivered by a pick roller to an image forming unit and a coil spring that attenuates vibration of a retard roller.
JP 2000-168972 A

  However, in the recording paper transport mechanism described above, when a plurality of recording papers are interposed between the separation pad and the pick roller, the pick roller excessively vibrates and the operation sound of the image forming apparatus increases. There is. Even if the coil spring disclosed in Patent Document 1 is used, vibration of the pick roller cannot be suppressed.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of reducing operation noise by suppressing vibration of a pick roller.

  In order to achieve the above object, the invention according to claim 1 is a photoconductor drum having a photoconductor coated on the surface, a charging means for uniformly charging the surface of the photoconductor drum, and a laser beam scanned on the surface of the photoconductor. Exposure means for forming a latent image by irradiation, developing means for forming a toner image by attaching toner to a portion of the surface of the photosensitive member where the latent image is formed, and development in the rotational direction of the photosensitive drum A transfer means provided to face the surface of the photosensitive drum at a predetermined transfer position downstream of the means, and for transferring the toner image formed on the surface of the photosensitive drum onto the recording paper; and a toner image A fixing means for fixing the toner image on the recording paper by applying predetermined heat and pressure to the recording paper on which the toner is transferred, a recording paper holding means for holding the loaded recording paper, and a recording held by the recording paper holding means Transport paper to transfer position In the image forming apparatus including the recording paper transport mechanism, the recording paper transport mechanism supports the pick roller that feeds the top one of the recording papers held by the recording paper holding unit, and the pick roller. A shaft member that rotates integrally, a pick roller housing that rotatably supports the shaft member, and another recording paper that is held by the recording paper holding mechanism by pressing the recording paper fed by the pick roller against the pick roller. A separation pad for separating from the recording paper, and an urging means for urging the separation pad toward the pick roller; the shaft member is formed hollow by bending the metal plate into a U-shape; The pick roller housing is formed radially from the housing main body, a bearing that rotatably supports the shaft member, and the bearing, thereby strengthening the coupling between the bearing and the housing main body. A plurality of reinforcing ribs, and at least the direction in which the recording paper enters the pick area by the pick roller from the recording paper holding means and the pick roller is pressed by the separation pad through the recording paper. And the direction in which the recording paper is sent out from the pick area by the pick roller, vibration of the pick roller when a plurality of recording papers are interposed between the separation pad and the pick roller. It suppresses and reduces operating noise.

  According to a second aspect of the present invention, an image forming means for forming an image on a recording paper, a recording paper holding means for holding a loaded recording paper, and a recording paper held on the recording paper holding means are conveyed to the image forming means. In an image forming apparatus provided with a recording paper transport mechanism, the recording paper transport mechanism is integrated with a pick roller for feeding the uppermost recording paper held by the recording paper holding means, and supporting the pick roller. Rotating shaft member, a pick roller housing that rotatably supports the shaft member, and other recordings held by the recording paper holding means by pressing the recording paper fed by the pick roller against the pick roller The shaft member is formed hollow by bending a metal plate into a U-shape, and the pick roller housing can freely rotate the housing main body and the shaft member. A bearing portion to be supported and a reinforcing rib formed radially from the bearing portion to reinforce the coupling between the bearing portion and the housing main body, and a plurality of recording papers are interposed between the separation pad and the pick roller In this case, the vibration of the pick roller is suppressed.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the reinforcing rib includes a direction in which the recording paper enters the pick area by the pick roller from the recording paper holding means, and the pick roller passes through the recording paper. The recording paper is disposed in the direction pressed by the separation pad and in the direction in which the recording paper is sent out by the pick roller from the pick area.

  According to the first aspect of the present invention, since a plurality of reinforcing ribs that reinforce the coupling between the bearing portion and the housing body portion are formed radially around the bearing portion of the pick roller housing, the force applied to the pick roller Is distributed to the housing body through the reinforcing ribs. In particular, the reinforcing rib includes at least the direction in which the recording paper enters the pick area by the pick roller from the recording paper holding means, the direction in which the pick roller is pressed by the separation pad through the recording paper, and the recording paper in the pick area. Therefore, when the paper is fed by the pick roller, the coupling between the bearing portion and the housing main body portion can be strengthened in the direction in which a load is applied. Thereby, the vibration of the pick roller when a plurality of recording sheets are interposed between the separation pad and the pick roller can be suppressed, and the operation sound of the image forming apparatus can be reduced. Therefore, while using a hollow shaft member formed by bending a metal plate into a U-shape, the operation sound of the image forming apparatus can be suppressed to a level that does not cause a problem in practice, and the image forming apparatus can be easily used. Cost reduction.

  According to the second aspect of the present invention, since the reinforcing ribs that reinforce the coupling between the bearing portion and the housing main body are formed radially around the bearing portion of the pick roller housing, the force applied to the pick roller is increased by the reinforcing rib. It is distributed to the housing main body via Thereby, while using a hollow shaft member formed by bending a metal plate into a U-shape, the operation sound of the image forming apparatus can be suppressed, and the cost of the image forming apparatus can be easily reduced. Can do.

  According to the invention of claim 3, the reinforcing rib is at least a direction in which the recording paper enters the pick area by the pick roller from the recording paper holding means, and a direction in which the pick roller is pressed by the separation pad through the recording paper. Since the recording paper is disposed in the direction in which the recording paper is sent out from the pick area by the pick roller, when the paper is fed by the pick roller, the coupling between the bearing portion and the housing main body portion can be strengthened in the direction in which a load is applied. And vibration of the pick roller can be further suppressed.

  A laser beam printer according to the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 shows a configuration example of the laser beam printer 1. A laser beam printer 1 includes a photosensitive drum 2, a cleaner 3, a charger 3, a charger (charging means) 4, a laser scanning unit (exposure means) 5, a developing brush (developing means) 6, and a transfer roller. (Transfer means) 7, fixing roller (fixing means) 8 disposed downstream of the transfer roller 7 in the conveying direction of the recording paper P, paper feed tray 9 loaded with the recording paper P, printed recording A paper discharge unit 10 on which the paper P is deposited, a recording paper transport mechanism 11 that transports the recording paper P loaded in the paper feed tray 9 to the position of the photosensitive drum 2, a housing 14 that accommodates the above parts, and the like. ing.

  The cleaner 3 removes toner and paper dust before one stroke (one rotation) adhering to the surface of the photosensitive drum 2 and cleans the drum surface. The charger 4 uniformly charges the surface of the photosensitive drum 2 cleaned by the cleaner 3. The laser scan unit 5 forms a latent image by irradiating the surface of the photosensitive drum 2 charged by the charger 4 while scanning the laser beam L. The developing brush 6 is mounted on a toner cartridge 15 filled with toner, and forms a toner image by attaching toner to a portion of the surface of the photosensitive drum 2 where a latent image is formed. The transfer roller 7 is provided so as to face the surface of the photosensitive drum 2, and charges the surface of the recording paper P while pressing the recording paper P against the surface of the photosensitive drum 2, so that the surface of the photosensitive drum 2 is charged. The formed toner image is transferred onto the recording paper P. The recording paper P on which the image is formed on the surface by the transfer roller 7 is conveyed to the fixing roller 8. The fixing roller 8 fixes the toner by applying heat and pressure while sandwiching the recording paper P together with the pressing roller 16 disposed opposite to the fixing roller 8. Heat for fixing the toner is supplied from a heater (for example, a halogen lamp) built in the fixing roller 8. As described above, the photosensitive drum 2, the charger 4, the laser scan unit 5, the developing brush 6, the transfer roller 7, the fixing roller 8, and the like constitute an image forming unit.

  FIG. 2 shows the recording paper transport mechanism 11. The recording paper transport mechanism 11 rotates integrally while supporting the pick roller 21 and the pick roller 21 that sends the uppermost recording paper held in the paper feed tray 9 to the vicinity of the photosensitive drum 2. Shaft member 22 that rotates, a pick roller housing 23 that rotatably supports the shaft member 22, and other recordings that are held on the paper feed tray 9 by pressing the recording paper delivered by the pick roller 21 against the pick roller 21 A separation pad 24 that separates from the paper and a coil spring (biasing means: see FIG. 4) 25 that urges the separation pad 24 toward the pick roller 21 are configured.

  The shaft member 22 is formed in a hollow structure with an open cross section by bending a metal plate into a U-shape. Therefore, as compared with a solid shaft member that is normally used, the vibration associated with the rotation and feeding of the pick roller 21 increases, and the operation sound of the laser beam printer 1 increases accordingly. Therefore, when such a shaft member 22 is applied to the recording paper transport mechanism 11 of the laser beam printer, it is necessary to take measures for suppressing the vibration of the pick roller 21 on the pick roller housing 23.

  FIG. 3 shows the pick roller housing 23. The pick roller housing 23 is formed of, for example, a synthetic resin, and includes a housing main body portion 30, a bearing portion 31 that rotatably supports the shaft member 22, and a reinforcing rib that reinforces the coupling between the bearing portion 31 and the housing main body portion 30. 32.

  FIG. 4 shows the arrangement of the reinforcing ribs 32. Eight reinforcing ribs 32 are radially spaced from the bearing portion 31 at an angle of approximately 45 °. Among these, the reinforcing ribs 32a, 32b, and 32c are particularly effective for strengthening the synthesis of the bearing portion 31. The reinforcing rib 32 a is disposed in the direction A in which the recording paper enters the pick area X from the paper feed tray 9 by the pick roller 21, and downstream of the bearing portion 31 in the recording paper entry direction. . Further, the reinforcing rib 32b is disposed in a direction B in which the pick roller 21 is pressed by the separation pad 24 via the recording paper and in a direction opposite to the separation pad 24 with respect to the bearing portion 31. . Further, the reinforcing rib 32 c is disposed in the direction C in which the recording paper is sent out from the pick area X by the pick roller 21, and downstream of the bearing portion 31 in the recording paper sending direction.

According to the laser beam printer 1 configured as described above, the eight reinforcing ribs 32 that reinforce the coupling between the bearing portion 31 and the housing body portion 30 are radially formed around the bearing portion 31 of the pick roller housing 23. Thus, the force applied to the pick roller 21 is distributed to the housing body 30 via the reinforcing rib 32. As a result, vibration of the pick roller 21 when a plurality of recording papers are interposed between the separation pad 24 and the pick roller 21 can be suppressed, and operation noise of the laser beam printer 1 can be reduced. Further, the reinforcing rib 32a is in the direction A in which the recording paper enters the pick area X by the pick roller 21 from the paper feed tray 9, and the reinforcing rib 32b is in the direction B in which the pick roller 21 is pressed by the separation pad 24. Since the reinforcing ribs 32c are respectively arranged in the direction C in which the recording paper is sent out from the pick area X by the pick roller 21, when the paper is fed by the pick roller 21, the bearing portion 31 and the housing main body in the direction in which a load is applied. The bond with the part 30 can be strengthened,
The vibration of the pick roller 21 can be further suppressed. Thereby, while using the shaft member 22 formed by bending the metal plate into a U-shape, the operation sound of the laser beam printer 1 can be suppressed to a level that does not cause a problem in practice, and the laser beam can be easily obtained. The cost of the printer can be reduced.

  Note that the present invention is not limited to the configuration of the above-described embodiment, and at least around the bearing portion 31 of the pick roller housing 23, three reinforcing ribs 32a that reinforce the coupling between the bearing portion 31 and the housing main body portion 30; 32b and 32c should just be formed radially. Further, the reinforcing rib 32 may be added at a position opposite to the reinforcing ribs 32a, 32b, 32c with the bearing portion 31 interposed therebetween. The present invention can be modified in various ways. For example, the recording paper transport mechanism 11 can be widely applied to an image forming apparatus such as an ink jet printer.

The figure which shows the structure of the laser beam printer by one Embodiment of this invention. FIG. 3 is a perspective view showing a recording paper transport mechanism of the printer. The perspective view which shows the pick roller housing of the mechanism. The side view which shows arrangement | positioning of the reinforcement rib of the pick roller housing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser beam printer 2 Photosensitive drum 4 Charger (charging means)
5 Laser scan unit (exposure means)
6 Developing brush (Developing means)
7 Transfer roller (transfer means)
8 Fixing roller (fixing means)
9 Paper feed tray (recording paper holding means)
DESCRIPTION OF SYMBOLS 11 Recording paper conveyance mechanism 21 Pick roller 22 Shaft member 23 Pick roller housing 24 Separation pad 25 Coil spring (biasing means)
30 Housing Body 31 Bearing 32 Reinforcing Rib

Claims (3)

A photoreceptor drum having a photoreceptor coated on the surface;
Charging means for uniformly charging the surface of the photosensitive drum;
Exposure means for forming a latent image by irradiating the surface of the photoconductor while scanning with a laser beam;
Developing means for forming a toner image by attaching toner to a portion of the surface of the photoreceptor where a latent image is formed;
A toner image formed on the surface of the photosensitive drum is recorded at a predetermined transfer position downstream of the developing unit in the rotational direction of the photosensitive drum so as to face the surface of the photosensitive drum. Transfer means for transferring onto paper,
Fixing means for applying a predetermined heat and pressure to the recording paper on which the toner image has been transferred to fix the toner image on the recording paper;
Recording paper holding means for holding the loaded recording paper;
In an image forming apparatus comprising a recording paper transport mechanism for transporting the recording paper held by the recording paper holding means to the transfer position,
The recording paper transport mechanism includes a pick roller for feeding the uppermost recording paper held by the recording paper holding means, a shaft member that rotates integrally while supporting the pick roller, and the shaft A pick roller housing that rotatably supports a member; a separation pad that presses the recording paper delivered by the pick roller against the pick roller and separates it from other recording paper held by the recording paper holding mechanism; Biasing means for biasing the separation pad toward the pick roller;
The shaft member is formed hollow by bending a metal plate into a U-shape,
The pick roller housing includes a housing main body, a bearing that rotatably supports the shaft member, and a plurality of reinforcements that are formed radially from the bearing and reinforce the coupling between the bearing and the housing main body. Ribs,
The reinforcing rib includes at least a direction in which the recording paper enters the pick area by the pick roller from the recording paper holding means, a direction in which the pick roller is pressed by the separation pad through the recording paper, and the recording paper By being arranged in the direction of being sent out by the pick roller from the pick area, vibration of the pick roller when a plurality of recording sheets are interposed between the separation pad and the pick roller is suppressed. An image forming apparatus that reduces operation noise. Image forming means for forming an image on recording paper;
Recording paper holding means for holding the loaded recording paper;
In an image forming apparatus comprising a recording paper transport mechanism for transporting the recording paper held by the recording paper holding means to the image forming means,
The recording paper transport mechanism includes a pick roller for feeding the uppermost recording paper held by the recording paper holding means, a shaft member that rotates integrally while supporting the pick roller, and the shaft A pick roller housing that rotatably supports a member; and a separation pad that presses the recording paper delivered by the pick roller against the pick roller and separates it from other recording paper held by the recording paper holding means. Have
The shaft member is formed hollow by bending a metal plate into a U-shape,
The pick roller housing includes a housing main body, a bearing that rotatably supports the shaft member, and a reinforcing rib that is formed radially from the bearing and reinforces the coupling between the bearing and the housing main body. Have
An image forming apparatus, wherein vibration of the pick roller is suppressed when a plurality of recording sheets are interposed between the separation pad and the pick roller.   The reinforcing rib includes a direction in which the recording paper enters the pick area by the pick roller from the recording paper holding means, a direction in which the pick roller is pressed by the separation pad through the recording paper, and the recording paper in the pick. The image forming apparatus according to claim 2, wherein the image forming apparatus is disposed in a direction in which the pick roller is fed from a region.

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