JPH04233557A - Image recorder - Google Patents

Abstract

PURPOSE:To allow the moving speed of a photosensitive drum to coincide with that of an intermediate transfer drum, to eliminate slip or vibration and to obtain an excellent image without jitter by transferring the rotational driving of a driving part which is provided in either of the photosensitive drum and the intermediate transfer drum to the other drum by frictional force. CONSTITUTION:The driving part 3 for driving the drum is provided in either the photosensitive drum 1 or the intermediate transfer drum 2. The other drum where the driving part 3 is not provided is brought into contact with the outer peripheral surface of the drum which is driven to be rotated by the driving part 3, so that it is driven to be rotated by the frictional force.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image recording apparatus, and more particularly, a photoreceptor drum on which a toner image is formed, and an intermediate transfer drum that presses the photoreceptor drum and transfers and holds the toner image. The present invention relates to an image recording device having the following.

0002

2. Description of the Related Art As shown in FIG.
The image forming means 20Y, 20M, 20C, and 20K for each color of M), cyan (C), and black (K) are connected to the intermediate transfer drum 2.
There were some placed around the. The image recording device sequentially transfers the toner images formed on the photoreceptor drums 1Y, 1M, 1C, and 1K of the respective image forming means 20Y, 20M, 20C, and 20K to the intermediate transfer drum 2 in an overlapping manner, and then transfers the toner images to the recording paper 12.
A color image is obtained by transferring the image to a computer. That is,
The intermediate transfer drum 2 rotates clockwise, and the surfaces of the photosensitive drums 1Y, 1M, 1C, and 1K are in contact with the intermediate transfer drum 2. Each photosensitive drum 1 rotates counterclockwise in synchronization with the clockwise rotation of the intermediate transfer drum 2. At this time, the toner image formed on the surface of the photosensitive drum 1 is transferred to the intermediate transfer drum 2 due to the potential difference applied between both drums. In the case of color, toner images of different colors (yellow, magenta, cyan, black) are formed on each photoreceptor drum 1Y, 1 by a plurality of toner image forming means.
After being formed on M, 1C, and 1K and sequentially superimposed and transferred onto the intermediate transfer drum 2, the combined color toner image is transferred from the back side of the recording paper to a transfer roller to which a voltage of opposite polarity to the toner is applied. By pressing it, it is transferred to the recording paper,
The image is fixed by the fixing device 8. In a color image recording device in which such photosensitive drums are arranged around an intermediate transfer drum, for example, as shown in FIG. 4 as a first conventional example, each drum 1, 2 is rotated. Either separate motors 31 and 32 are provided to drive the intermediate transfer drum 2, or as a second conventional example, as shown in FIG. A gear 40 is provided, and the intermediate transfer drum 2
The rotational driving force for the photosensitive drum 1 is transmitted through the gear 33.
It was used for driving.

0003

However, in these image recording apparatuses, the circumferential speed of the drum changes due to the eccentricity of each drum or due to a change in the diameter of the drum due to the pressing of the drum. Therefore, even if the reduction ratios of the gears are matched or the individual drive motors are controlled so that the rotational speeds of each drum are the same, the circumferential speeds on the drum surfaces differ slightly and the drums have relative speeds. Therefore, the surfaces on which the drums are pressed may slip, or the positioning control of the drive motors for each drum may lose synchronization, causing chatter vibrations in the drums.
Jitter) occurs, which has a negative effect on the image. The present invention has been made to solve the above problems, and it is possible to match the moving speeds of the surfaces of the photoreceptor drum and the intermediate transfer drum, eliminate vibrations caused by slippage and step-out of the drive source, and reduce jitter. The purpose of this invention is to provide an image recording device that can obtain good images.

0004

[Means for Solving the Problems] In order to solve the above-mentioned technical problems, the present invention, as shown in FIG. In an image recording apparatus having an intermediate transfer drum 2 that transfers and holds a toner image, only one of the photosensitive drum 1 and the intermediate transfer drum 2 is provided with a drive section 3 that drives the drum, and a drive section 3 that drives the drum is provided. The other drum, which is not provided with the section 3, is brought into contact with the drum rotated by the drive section 3 on its outer peripheral surface, thereby being rotationally driven by frictional force.

[0005]

[Operation] In the present invention, either the photosensitive drum 1 or the intermediate transfer drum 2 is rotated by the drive section 3 provided on the drum for driving the drum. Driven. Then, the other drum, which is not provided with the drive section 3, comes into contact with the outer peripheral surface of the drum that has been rotationally driven by the drive section 3, and is thereby rotationally driven by frictional force. Therefore, even if the drum diameter changes slightly due to drum eccentricity or drum pressing, both drums transmit rotational force through contact, so regardless of the eccentricity or change in diameter, the circumferential speed can be kept the same. The image is transferred in this state.

[0006]

Embodiment Next, an image recording apparatus according to an embodiment of the present invention will be described. FIG. 3 shows the entire color image recording apparatus according to this embodiment. For example, as shown in the figure, the apparatus includes image forming means 10Y for each color of yellow (Y), magenta (M), cyan (C), and black (K).
, 10M, 10C, and 10K are arranged around the intermediate transfer drum 2. The image recording device includes a photosensitive drum 1Y of each image forming means 10Y, 10M, 10C, and 10K.
The toner images formed on 1M, 1C, and 1K are sequentially transferred onto the intermediate transfer drum 2 in an overlapping manner, and then transferred onto the recording paper 12.
This is to obtain a color image. Note that the reference numeral 8 in FIG. 3 indicates a fixing device, which fixes the image transferred to the recording paper 12, and the reference numeral 9 indicates a fixing device that fixes the image transferred to the recording paper 12. It is used to remove residual toner, and reference numeral 11 is a transfer roller provided at a location where the transfer from the intermediate transfer drum 2 to the recording paper 12 is performed. FIG. 2 also shows a photosensitive drum 1 that forms a toner image, which is one of the image forming means for each color;
An intermediate transfer drum 2 that transfers and holds the toner image created on the photosensitive drum 1, a motor 32 that rotationally drives the intermediate transfer drum 2, and a rotational force of the motor 32 that is transmitted to the intermediate transfer drum 2. A gear 33 for transferring the photoreceptor drum 1 to the intermediate transfer drum 2, for example, with a linear pressure of 10 g.
It has a spring 4 for pressing at a pressure of /cm. In addition, each of the image forming means 10 includes, as shown in FIG. 3, a developing device 5, an exposure LED 6, and a charger 7 for uniformly charging the surface of the photosensitive drum 1. The intermediate transfer drum 2 is, for example, a drum made of aluminum, whose surface is lined with 5 mm thick urethane rubber having a hardness of 60 degrees and an electrical resistivity of 10 6 Ω·cm.

Next, the operation of this embodiment will be explained. The photosensitive drum 1 is pressed against the intermediate transfer drum 2 by the spring 4. Due to this pressing, the driving force from the drive motor 32 is first transmitted to the intermediate transfer drum 2. The contact friction coefficient between the surface of the intermediate transfer drum 2 and the surface of the photoreceptor drum 1 is sufficiently large, and the photoreceptor drum 1 is driven by the frictional force between the surface of the intermediate transfer drum and the pressing surface. At this time,
Since both drums rotate in rolling contact, their circumferential speeds are equal,
Rotates smoothly. Along with this rotation, in the toner image forming means 10 of each color, an image is optically projected by the exposure LED 6 onto the photosensitive drum 1 charged by the charger 7, and an electrostatic latent image is formed. Toner of each color supplied from the developing device 5 electrostatically adheres to the electrostatic latent image thus created, thereby making the electrostatic latent image visible and creating a toner image. Thereafter, the toner image on the photoreceptor drum 1 is colored in different colors (yellow, magenta, cyan, black) depending on the potential difference between the voltages applied to each drum at the contact point between the photoreceptor drum 1 and the intermediate transfer drum 2. The toner images are transferred onto the intermediate transfer drum 2 in a superimposed manner, and the combined toner image is transferred onto the recording paper 12 by pressing the transfer roller 11 to which a voltage of opposite polarity to the toner is applied from the back of the recording paper 12. transcribed. Recording paper 1
The toner image on 2 is fixed by a fixing device 8 to obtain a color image.

[0008]

As explained above, in the present invention, by bringing the photoreceptor drum and the intermediate transfer drum into contact with each other on their outer peripheral surfaces, the rotation of the drive unit provided on either the photoreceptor drum or the intermediate transfer drum is improved. The drive is transmitted to the other drum by frictional force. Therefore, the moving speeds of the photoreceptor drum and the intermediate transfer drum match, eliminating vibrations due to slippage and loss of synchronization of the drive source, and making it possible to obtain good images without jitter.

[0009]

[Brief explanation of the drawing]

[Figure 1] Diagram explaining the principle of the invention

[Fig. 2] A diagram showing the main parts of the device according to the embodiment.

FIG. 3 is a diagram showing a color image recording device according to an embodiment.

[Fig. 4] A diagram showing the main parts of the device according to the first conventional example.

[Fig. 5] A diagram showing the main parts of a device according to a second conventional example.

[Explanation of symbols]

1 Photoreceptor drum 2 Intermediate transfer drum 3 Drive section 4 Spring 5 Developing device 6 Exposure LED 7 Charger 8 Fuser 31, 32 Motor

Claims (1)

[Claims] Claim 1: A photosensitive drum (1) on which a toner image is created.
and an intermediate transfer drum (2) that presses against the photoreceptor drum (1) and transfers and retains the toner image, whichever of the photoreceptor drum (1) or the intermediate transfer drum (2) is used. Only one of the drums is provided with a drive section (3) for driving the drum, and the other drum, which is not provided with the drive section (3), is provided with a drive section (3).
1. An image recording device characterized in that the image recording device is rotationally driven by frictional force by contacting the outer circumferential surface of the drum with the drum that is rotationally driven by the drum.