JPH05107902A - Recording device - Google Patents

Abstract

PURPOSE:To provide a recording device where an image is not disturbed when a roller body such as a developing roller contacts with/separates from an image forming body such as a photosensitive drum as a recording device in which the roller body such as the developing roller contacts with/separates from the image forming device such as the photosensitive drum. CONSTITUTION:This device is constituted by providing the image forming body (photosensitive drum) 1 where the image which is to be transferred to another medium is formed on its surface and which is constantly turned at a 1st specified circumferential speed, the roller body (developing roller) 5 which is allowed to contact with/separate from the image forming body 1 and driven to be rotated at a 2nd specified circumferential speed different from that of the image forming body 1 in the case that it contacts with the image forming body 1, and a circumferential speed control means (control part) 50 which sets the circumferential speed of the roller body 5 to the circumferential speed at which load fluctuation given to the image forming body 1 is smaller than the 2nd specified circumferential speed in the case that the roller body 5 contacts with the image forming body 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus in which a roller body such as a developing roller is brought into contact with and separated from an image forming body such as a photosensitive drum.

In a color printer or the like, a full-color image is obtained by sequentially developing and developing each color by sequentially contacting and separating each developing roller of a plurality of developing devices for developing with each color toner from an outer peripheral surface of a photosensitive drum. There are things that I tried to get.

[0003]

2. Description of the Related Art As a method of rotating a developing roller, there are a so-called counter method and a with method.

In the counter method, the contact surfaces of the developing roller and the photosensitive drum are driven to rotate in opposite directions. Even in the case of the with method in which the contact surface is driven to rotate in the same direction, the movement of the peripheral surface of the developing roller does not match the movement of the peripheral surface of the photosensitive drum. The peripheral speed of the developing roller is driven so as to move at a higher speed (for example, three times) than the peripheral speed of the photosensitive drum so that a large amount of toner can be supplied.

[0005]

However, in the case where the developing roller is brought into contact with and separated from the photosensitive drum, if the peripheral speed of the photosensitive drum and the peripheral speed of the developing roller are significantly different, At the time of contact / separation, particularly when the developing roller is brought into contact with the photosensitive drum, the load applied to the photosensitive drum changes abruptly, causing uneven rotation of the photosensitive drum and disturbing the image.

This image disturbance occurs in both the exposure portion for forming an electrostatic latent image on the surface of the photosensitive drum and the transfer portion for transferring the toner image from the surface of the photosensitive drum, and the image quality is significantly deteriorated. Cause

Therefore, an object of the present invention is to provide a recording apparatus in which an image is not disturbed when a roller body such as a developing roller comes into contact with or separates from an image forming body such as a photosensitive drum.

[0008]

In order to achieve the above object, a recording apparatus of the present invention will be described with reference to FIG.
As shown in FIG. 3, the image formed on the surface on which an image to be transferred to another medium is formed, and the image forming body 1 rotated at a constant first speed at a predetermined first peripheral speed is contacted with the image forming body 1. A roller body 5 that is separated and is rotationally driven at a predetermined second peripheral speed different from the peripheral speed of the image forming body 1 when in contact with the image forming body 1;
When the roller body 5 comes into contact with the image forming body 1, the peripheral speed of the roller body 5 is set to a peripheral speed that causes less load fluctuation to be applied to the image forming body 1 compared to the predetermined second peripheral speed. The peripheral speed control means 50 is provided.

The peripheral speed of the roller body 5 set by the peripheral speed control means 50 may be substantially the same as the predetermined first peripheral speed of the image forming body 1,
Further, when the roller body 5 separates from the image forming body 1, the peripheral speed control means 50 sets the peripheral speed of the roller body 5 to the image forming body 1 as compared with the predetermined second peripheral speed. You may make it set to the peripheral speed with which the load fluctuation given is small.

[0010]

When the roller body 5 comes into contact with or separates from the image forming body 1, the load of the image forming body 1 is reduced so that, for example, the peripheral speed of the image forming body 1 becomes equal to the peripheral speed of the image forming body 1. The peripheral speed is set by the peripheral speed control means 50.

[0011]

Embodiments will be described with reference to the drawings. Figure 2
Yellow (Y), magenta (M), cyan (C) and black (B)
4 shows a full-color printer configured to perform full-color printing with the four color toners.

In the figure, 1 is a predetermined peripheral velocity V in the direction of arrow A.
1 is a photosensitive drum that is rotationally driven at a constant speed, and the surface uniformly charged by the pre-charger 2 is irradiated with image light by the exposure device 3 to form an electrostatic latent image.

4 toners for yellow, magenta, cyan and black
Color developing devices 4Y, 4M, 4C, 4
In B, developing rollers 5Y, 5M, 5C and 5B are rotatably provided.

The developing rollers 5Y, 5M, 5C and 5B are rotationally driven in the width direction by a developing motor, and the toners in the developing devices 4Y, 4M, 4C and 4B for the respective colors are conveyed. Then, each time the photosensitive drum 1 rotates, the developing rollers 5Y, 5Y
M, 5C, and 5B are sequentially brought into contact with the outer peripheral surface of the photosensitive drum 1 one by one, and the electrostatic latent images are sequentially developed with the toners of the respective colors. Development rollers 5Y, 5M, 5 that have completed development
C and 5B are separated from the outer peripheral surface of the photosensitive drum 1.

Numeral 7 is a contact portion with the photosensitive drum 1 in the same direction,
The toner image on the photosensitive drum 1 is an intermediate transfer belt that is rotated at the same speed as the peripheral speed V1 of the photosensitive drum 1. The toner image on the photosensitive drum 1 is transferred onto the surface of the intermediate transfer belt 7 by superposition by discharge of the transfer corotron 8. (Primary transfer). Reference numeral 9 is a cleaner for cleaning the toner remaining on the photosensitive drum 1 without being transferred.

The recording sheet 100 is taken out from the cassette 11 and is temporarily stopped at the nip portion of the stopped registration roller 12 so that the recording sheet 100 is timed with the recording process. After that, the recording paper 100 is sent to the transfer roller 13 by the registration roller 12 which has restarted rotation, and the full-color toner image superposed on the intermediate transfer belt 7 is transferred onto the recording paper 100.

Then, the recording sheet 100 is further sent to the fixing device 14, and the fixing roller 15 and the pressure roller 16 are provided.
The full-color toner image is fixed on the recording paper 100 by the heat and pressure applied from the.

The transfer roller 13 and the cleaner blade 18 are separated from the intermediate transfer belt 7 while the four color toner images are transferred on the intermediate transfer belt 7 in an overlapping manner. When the transfer of the toner image is completed, the transfer roller 13 causes the intermediate transfer belt 7 and the recording paper 1 to move.
00 and 00 are pressed against the inner roller 19 so that the full-color image is collectively transferred to the recording paper 100 (secondary transfer).

When the transfer onto the recording paper 100 is completed, the transfer roller 13 is separated from the inner roller 19. At the same time, the cleaner blade 18 is pressed against the inner roller 20 with the intermediate transfer belt 7 sandwiched therebetween, and the toner remaining on the surface of the intermediate transfer belt 7 is cleaned. After the cleaning is completed, the cleaner blade 18 is separated from the inner roller 20.

FIG. 1 shows four color developing devices 4Y, 4M,
One of the developing devices 4C and 4B and its developing roller 5 are shown, and each of the developing devices 4Y, 4M, 4C and 4B is constructed in this way.

The developing device 4 is provided so as to be movable in a direction of approaching and retreating to the outer peripheral surface of the photosensitive drum 1, and is biased by a compression coil spring 41 in a direction of being pressed against the outer peripheral surface of the photosensitive drum 1. .. The movement of the developing device 4 is restricted by the eccentric cam 42, and depending on the direction of the eccentric cam 42, the developing roller 5 is pressed against the photosensitive drum 1 to come into contact with it and the developing roller 5 is separated from the photosensitive drum 1. Switched to.

The electromagnetic clutch 4 is provided between the eccentric cam 42 and the cam driving motor 43 for rotating the eccentric cam 42.
4 is interposed, the clutch 44 is engaged and disengaged to arbitrarily control the stop angle of the eccentric cam 42, and the developing roller 5 is brought into contact with and separated from the photosensitive drum 1. You can switch to the state.

A gear 47 connected to the developing motor 46 is rotatably supported by the frame and connected to the developing roller 5.
Is rotatably supported by the developing device 4, and both gears 47, 48
When the developing roller 5 is in contact with the photosensitive drum 1, they mesh with each other, and if the developing roller 5 moves away from the photosensitive drum 1, a gap can be formed between the gears 47 and 48 as shown in FIG. A control unit 50 controls the operation of the clutch 44 and the rotation speed of the developing motor 46.

FIG. 3 is a time chart showing the operation of the above-described embodiment. The developing roller 5 is moved to the photosensitive drum 1 by switching the connection / disconnection state of the electromagnetic clutch 44 in conjunction with the exposure operation by the exposure device 3. The outer peripheral surface of the.

When the developing roller 5 comes into contact with the photosensitive drum 1, the developing motor 46 is rotationally driven by the developing motor 46 at the same slow peripheral speed V1 as that of the photosensitive drum 1, and the rotational speed increases after the contact and before the start of the developing operation. Thus, during the developing operation, it is rotationally driven at a predetermined high peripheral speed V2. Then, when the developing roller 5 is separated from the photosensitive drum 1, the developing roller 5 is again moved to the photosensitive drum 1.
It is dropped to the same peripheral speed as.

Therefore, the developing roller 5 is the photosensitive drum 1
When they are brought into contact with or separated from the outer peripheral surface of the sheet, their peripheral velocities are the same, and the load fluctuation exerted on the photosensitive drum 1 by the developing roller 5 is extremely small. Therefore, uneven rotation does not occur on the photosensitive drum 1, and during development, a sufficient amount of toner is conveyed to the surface of the photosensitive drum 1 by the developing roller 5 rotating at high speed.

The present invention is not limited to the above embodiment, and the peripheral speed when the developing roller 5 is brought into contact with and separated from the photosensitive drum 1 does not necessarily have to be the same as that of the photosensitive drum 1. It is sufficient that the peripheral speed of 5 is smaller than that of the peripheral speed V2 at the time of development when the peripheral speed V2 is small.

Since the load fluctuation during the contact operation is much larger than the load fluctuation during the separation operation, the rotation speed of the developing roller 5 may be changed only during the contact operation. Similarly to the above, the rotation control of the transfer roller 13 may be applied.

The present invention is not limited to color printers,
The present invention can be applied to various devices such as a monochrome printer and other copying machines and facsimile machines.

[0030]

According to the recording apparatus of the present invention, when the roller body comes into contact with or separates from the image forming body, the peripheral speed control means controls the circumference of the roller body so that the load fluctuation applied to the image forming body becomes small. Since the speed is set, the rotation unevenness of the image forming body when the roller body comes into contact with and separates from the roller body is small, and it has an excellent effect that a good quality image without image disturbance or color misregistration can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of an embodiment.

FIG. 2 is an overall configuration diagram of a printer according to an embodiment.

FIG. 3 is a time chart showing the operation of the embodiment.

[Explanation of symbols]

 1 Photosensitive Drum (Image Forming Body) 5 Developing Roller (Roller Body) 50 Control Unit (Peripheral Speed Control Means)

Claims (3)

[Claims] 1. An image forming body (1) having an image transferred on another medium formed on its surface and rotated at a constant first speed at a predetermined first peripheral speed, and the image forming body (1). A roller body (5) that is brought into contact with and separated from the image forming body (1) and is rotationally driven at a predetermined second peripheral speed different from the peripheral speed of the image forming body (1) when in contact with the image forming body (1); When the roller body (5) contacts the image forming body (1), the peripheral speed of the roller body (5) is given to the image forming body (1) as compared with the predetermined second peripheral speed. A recording apparatus provided with a peripheral speed control means (50) for setting a peripheral speed in which load fluctuation is small. 2. The peripheral speed of the roller body (5) set by the peripheral speed control means (50) is the image forming body (1).
2. The recording apparatus according to claim 1, wherein the recording speed is substantially the same as the predetermined first peripheral speed of. 3. The roller body (5) is the image forming body (1).
When the peripheral speed control means (50) separates the peripheral speed of the roller body (5) from the predetermined second peripheral speed, the peripheral speed control means (50) exerts a small load fluctuation on the image forming body (1). The recording apparatus according to claim 1, wherein the recording speed is set to a speed.