JP2002268410A - Transfer device contact / separation mechanism - Google Patents

Abstract

(57) [Problem] To provide a color laser printer with a simple mechanism for performing an operation of bringing a transfer roller into contact with an intermediate transfer belt and an operation of separating a transfer roller from the intermediate transfer belt. . A contact / separation cam (15) is fixed to one end of a rotating shaft (35), an opposite phase cam (18) is fixed to the other end, and a spring clutch (17) is provided at the center. The anti-phase cam 18 is connected to the contact / separation cam 15.
And 180 ° out of phase. An arm 19 is provided in connection with the contact / separation cam 15, and a load arm 20 is provided in connection with the antiphase cam 18. A flapper type solenoid 22 is provided in connection with the spring clutch 17. The spring clutch 17 rotates half a turn at a time. Transfer roller 10
Moves in response to the movement of the arm 19, and moves toward and away from the intermediate transfer belt 8. The antiphase cam 18 and the load arm 20 apply a braking force to the rotation of the contact / separation cam 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer / contact mechanism of a transfer device applied to an image forming apparatus.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 2000-110906 discloses a "cam rotation control mechanism and an image forming apparatus using the same", an image forming means for forming a latent image on an image carrier, and an image forming means formed by the image forming means. Developing means for developing the latent image to form a developer image, a transfer means having a conductive elastic member in contact with the image carrier, and transferring the developer image to a transfer material; and Contacting / separating means for performing a contact / separation operation with respect to the image carrier, conveying means for conveying the transfer material to the transfer means, detecting means for detecting an abnormal conveyance of the transfer material conveyed by the conveying means, There is shown an image forming apparatus including a separation unit that separates the transfer unit from the image carrier in response to a detection unit. In the invention of Japanese Patent Application Laid-Open No. 2000-110906, the cam is prevented from being rotated by the cam shape and the layout of the shape center. Also, a one-way clutch is used to prevent reverse rotation.

[0003]

However, the cam shape cannot always be made into such a shape depending on the operation timing. In addition, the use of expensive parts such as a one-way clutch is disadvantageous in terms of cost.

Accordingly, an object of the present invention is to provide a contact / separation mechanism for a transfer device which solves the above-mentioned problem.

[0005]

According to the first aspect of the present invention,
The transfer member contacts and separates from the image carrier, and the transfer member contacts and separates the image carrier using a cam mechanism. When the small-diameter side of the cam contacts the transfer member, the transfer member contacts the image carrier. In a contact / separation mechanism of a transfer device having a configuration in which the cam member is in contact with an image carrier, the cam shaft applies a load equal to or more than the torque applied by the transfer mechanism to the cam shaft when the transfer member moves and contacts the image carrier. It is what it was.

By applying a load equal to or more than the torque applied to the camshaft to the camshaft by the force applied from the transfer mechanism, the camshaft is prevented from rotating due to the external force of the cam.

According to a second aspect of the present invention, in the contact / separation mechanism for the transfer apparatus according to the first aspect, a cam having an opposite phase is arranged coaxially with a cam for causing the transfer apparatus to perform a contact / separation operation. is there.

By arranging the cams of the opposite phase on the same axis as the cams that make the transfer device contact and separate, the operation of the cams is ensured by a simple mechanism.

According to a third aspect of the present invention, in the contact / separation mechanism of the transfer apparatus according to the second aspect, a force greater than the force exerted by the contact / separation cam from the transfer member acts on the cam of the opposite phase. is there.

[0010] The operation of the cam is ensured by applying a force greater than that received by the contact / separation cam from the transfer member to the cam of the opposite phase.

[0011]

FIG. 1 is a schematic diagram of a color laser printer according to the present invention. This color laser printer includes a photoreceptor unit, a charging unit, a writing unit, a developing unit, an intermediate transfer unit, a paper supply unit, a paper transfer unit, and a fixing unit.

A photoreceptor belt 1 is provided on the photoreceptor portion, and a charger 2, a developing device 3, and a photoreceptor cleaning device 4 are arranged around the photoreceptor belt 1. This photoreceptor belt 1
Has an organic photosensitive layer formed on its surface. The photoreceptor belt 1 is uniformly charged by applying a high voltage to the charger 2.

[0013] Color image information, for example, a color image signal from a computer is converted into an optical signal, and Bl
ack (hereinafter referred to as Bk), Cyan (same as C), Ma
The optical writing corresponding to the image signals of genta (same, M) and Yellow (same, Y) is performed via the polygon mirror 5, the f / θ lens 6, and the reflection mirror 7, and the electrostatic latent image is formed on the photosensitive belt 1. To form

This electrostatic latent image is composed of Bk, C, and Bk having toner charged with a charge opposite to that of the electrostatic latent image on the photosensitive belt 1.
The development is performed by electrostatically adsorbing the charged toner by each developing device 3 for each of M and Y. At the contact portion between the intermediate transfer belt 8 and the photosensitive belt 1, the toner image is transferred onto the intermediate transfer belt 8 by applying a charge opposite to that of the toner to the intermediate transfer belt 8. After the toner is transferred to the intermediate transfer belt 8, the photosensitive belt 11 is cleaned of residual toner and the like by the photosensitive member cleaning device 4, and is ready for the next image formation. In this embodiment, full-color four-color development is performed. By performing this operation four times, a four-color superimposed image is formed on the intermediate transfer belt 8, and this is transferred onto the transfer paper fed by the transport roller 9. The transfer is performed by applying a charge opposite to that of the toner to the toner. This transfer paper is conveyed to the fixing device 11, where the toner image is fused and fixed. Intermediate transfer belt 8
After the toner image is transferred to the transfer paper, the residual toner and the like are cleaned by the intermediate transfer cleaning device 12, and this color laser printer for the next image forming is such that the transfer member passes on the right side when viewed from the front of the machine. The right cover 13 is openable and closable. If a paper jam or the like occurs, the right cover 13 is opened to release the transfer path of the transfer member and to remove the transfer member having the paper jam. Can be.

Next, the mechanism around the paper transfer roller 10 will be described with reference to FIGS.

The paper transfer roller 10 is separated from the intermediate transfer belt 8 when a multi-color image is superimposed on the intermediate transfer belt 8, so that the intermediate transfer is completed immediately before the transfer paper is fed after the stacking is completed. Image transfer is performed by contacting the transfer belt 8 and passing the transfer member between the paper transfer roller 10 and the intermediate transfer belt 8. When forming a monochrome image, the paper transfer roller 10 remains in contact with the intermediate transfer belt 8.

The operation of contacting and separating the paper transfer roller 10 from the intermediate transfer belt 8 is performed by a cam 15. Paper transfer roller 10
Is attached to the holding member 14, and the holding member 14 itself is attached to the right cover 13 of the printer body. The holding member 14 is held on both sides by a shaft 30 protruding from the right cover 13, and can swing about the shaft 30. A spring 16 is sandwiched between the right cover 13 and the holding member 14 to generate a contact pressure when the paper transfer roller 10 contacts the intermediate transfer belt 8.

Next, the mechanism for contacting and separating the paper transfer roller will be described with reference to FIGS.

The paper transfer roller 10 is swingable by a cam mechanism. As shown in FIG. 5, the contact / separation cam 15 is fixed to one end of the rotating shaft 35, the antiphase cam 18 is fixed to the other end of the rotating shaft 35, and the spring clutch 17 is provided at the center of the rotating shaft 35. It is provided. An arm 19 is provided in connection with the contact / separation cam 15, a load arm 20 is provided in connection with the reverse phase cam 18, and a flapper type solenoid 22 is provided in connection with the spring clutch 17.

The contact / separation cam 15 and the reverse phase cam 18 are controlled to rotate halfway by a spring clutch 17 having a half-turn step. This half rotation operation of the spring clutch 17 is performed by a flapper type solenoid 22. As shown in FIG. 3, when the solenoid 22 is turned on, that is, when the solenoid 22 is pulled, the cam 15 is moved in the direction (X2 direction) for bringing the paper transfer roller into contact with the intermediate transfer belt. As shown in FIG. 4, when the solenoid 22 is in the OFF state, the paper transfer roller 10 moves in a direction in which the paper transfer roller 10 escapes (X1 direction).

The transfer roller 10 is brought into and out of contact with the intermediate transfer belt 8 by a contact / separation cam 15 which is in contact with an arm 19 fixedly attached to the transfer roller holding member 14 and is rotated. At the time of separation, as shown in FIG. 6A, the large-diameter side of the contact / separation cam 15 pushes the arm 19 to separate the paper transfer roller 10 from the intermediate transfer belt 8. At the time of contact, through the state shown in FIG. 6B, as shown in FIG.
The opposite is true. Here, when the spring 16 makes contact, the rotational force of the spring clutch 17 is supplied by a drive motor 41 via a gear train 40.

The anti-phase cam 18 is coaxial with the contact / separation cam 15 and the spring clutch 17,
° Out of phase. The load arm 20 is in contact with the antiphase cam 18. The load arm 20 is pressed against the reverse phase cam 18 by a tension spring 21.

FIGS. 6A to 6C and FIGS.
(C) shows the operation of the contact / separation cam 15 and the reverse phase cam 18. When the contact / separation cam 15 pushes the arm 19 on the large diameter side. The anti-phase cam 18 is in contact with the load arm 20 on the small diameter side. Next, when the solenoid 22 is turned on and the spring clutch 17 starts rotating, the contact / separation cam 15 receives a force from the arm 19 pressed together with the paper transfer roller holding member 14 by the spring 16, so that the direction in which the contact / separation cam 15 is rotated. Will be applied. In this case, since the internal spring of the spring clutch 17 opens, the brake does not work, and the output shaft is rotated by the force applied to the contact / separation cam 15, and the output shaft is rotated at a speed higher than the original rotation speed of the input gear. Try to. If the rotation continues, the paper transfer roller 10 comes into contact with the intermediate transfer belt 8 earlier than the intended timing. In addition, the impact at the time of contact becomes strong, and the vibration and rotation unevenness of the intermediate transfer belt 8 fluctuate. However, in the configuration of the present invention, the contact / separation cam 1
5. A cam 18 having a phase opposite to that of the contact / separation cam 15 is mounted coaxially with the spring clutch 17, and a load torque is applied to the opposite phase cam 18 by the load arm 20, so that the contact / separation cam 15 is likely to be rotated. However, the load torque applied to the opposite phase cam 18 (see FIG. 7A) plays a role of a brake, and the contact / separation cam 15 and the opposite phase cam 18 can rotate at the desired rotation speed. At this time, the tension spring 21 applied to the load arm is set so that a torque greater than the torque applied to the contact / separation cam is applied to the antiphase cam. If the torque by the load arm 20 becomes larger than the torque applied to the contact / separation cam, the paper transfer roller 10
Is opposite to the reverse phase cam 1 when the
Although 0 is turned, there is no problem even if the speed of separation of the paper transfer roller 10 is increased because the separation timing is not affected.

As described above, according to the first aspect of the present invention, the transfer member contacts and separates from the image carrier, and the transfer member contacts and separates from the image carrier by the cam mechanism. In the contact / separation mechanism of the transfer device, in which the transfer member contacts the image carrier when the small diameter side of the transfer member is in contact with the transfer member, the cam shaft moves when the transfer member moves and contacts the image carrier. Since the configuration is such that a load greater than the torque applied by the transfer mechanism is applied to the camshaft, the camshaft can be prevented from rotating due to the external force of the cam. So,
The operation of moving the transfer member toward and away from the image carrier can be stably performed.

According to a second aspect of the present invention, in the contact / separation mechanism of the transfer device according to the first aspect, a cam having an opposite phase is arranged coaxially with a cam for causing the transfer device to perform a contact / separation operation. Therefore, the operation of the cam can be ensured by a simple mechanism.

According to a third aspect of the present invention, in the contact / separation mechanism of the transfer device according to the second aspect, a force greater than the force exerted by the contact / separation cam from the transfer member acts on the cam of the opposite phase. Therefore, the operation of the cam can be ensured.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a color laser printer to which a contact / separation mechanism of a transfer device of the present invention is applied.

FIG. 2 is a perspective view of a contact / separation mechanism of the transfer device according to one embodiment of the present invention.

FIG. 3 is a diagram showing a state of a spring clutch when a flapper type solenoid is ON in FIG. 2;

FIG. 4 shows a flapper type solenoid OFF in FIG.
FIG. 7 is a diagram illustrating a state of the spring clutch when the state is.

FIG. 5 is a perspective view showing a contact / separation cam, a spring clutch, and an anti-phase cam.

FIG. 6 is a diagram showing a change in the position of an arm accompanying rotation of a contact / separation cam.

FIG. 7 is a diagram showing a relationship between the anti-phase cam and the load arm corresponding to FIG. 6;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor belt 2 charger 3 developing device 4 photoconductor cleaning device 8 intermediate transfer belt 9 transport roller 10 paper transfer roller 12 intermediate transfer cleaning device 13 cover 14 holding member 15 contact / separation cam 16 spring 17 spring clutch 18 reverse phase cam 19 Arm 20 Load arm 21 Extension spring 30 Axis 35 Rotation axis 41 Motor

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2H071 CA01 CA05 CA07 CA09 DA09 DA26 EA04 2H200 GA24 GA47 GA50 HA02 HB12 HB22 JA02 JB10 JB32 JC03 JC07 LA17 LA24 3J062 AA35 AB31 AC09 BA11 BA22 CC12 CC25

Claims (3)

[Claims] And a transfer mechanism that moves the transfer member toward and away from the image carrier by using a cam mechanism. A contact mechanism of the transfer device having a structure in which the cam shaft contacts the image carrier. When the transfer member moves and comes into contact with the image carrier, the cam shaft applies a load equal to or more than the torque applied by the transfer mechanism. A contact / separation mechanism for a transfer device, characterized in that the mechanism acts on a shaft. 2. The contact / separation mechanism of a transfer device according to claim 1, wherein a cam having an opposite phase is disposed coaxially with a cam that causes the transfer device to perform a contact / separation operation. . 3. The contact / separation mechanism of a transfer device according to claim 2, wherein a force greater than the force exerted by the contact / separation cam from the transfer member acts on the cam of the opposite phase. .