JPH0540394A - Color recording device - Google Patents

Abstract

PURPOSE:To obtain an image of high quality by preventing color slurring, blurring, and transfer absence at the time of transfer. CONSTITUTION:A squeezing device 18 for transfer paper is provided opposite to a dielectric film on a transfer drum 10 on the attraction side for the transfer paper 16 and right in front of a transfer position for a toner image. The transfer paper squeezing device 18 consists of a roller member and freely leaves and contacts the dielectric film to place a tension-directional frictional load toward the tail end side of the transfer paper.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a color recording apparatus. For example, it is applied to a printer of a digital copying machine or a digital color copying machine.

[0002]

2. Description of the Related Art In a color recording apparatus using a conventional electrophotographic system, image forming means for yellow (Y), magenta (M), cyan (C), and black (BK) are arranged in series to obtain a yellow image. In the forming means, a yellow toner image is formed on the transfer drum and transferred to the recording paper by the transfer discharger. Then, similarly, magenta, cyan, and black toner images are sequentially transferred onto the recording paper, and the color image is transferred. I will get it. In such a multi-drum type color recording device,
Although it is easy to increase the recording speed, it is difficult to match the transfer position of each color toner image on the recording paper.
It has been a big problem to convey the recording paper accurately and stably.

In order to solve this point, for example, a "recording paper conveying mechanism" has been proposed in Japanese Patent Laid-Open No. 2-79058. In order to ensure that the recording paper is conveyed at a constant speed, the one disclosed in this publication ensures the method of attaching the recording paper to the front end holding means for holding the front end of the recording paper and the endless belt for driving the front end holding means in the conveying direction. A support shaft rearward in the transport direction is provided on the same line as the recording paper holding boundary, which is the boundary between the front end holding means and the recording paper, or above the recording paper holding boundary. However, when the recording paper is simply placed on the insulating wire and there is curl or the like, color misregistration easily occurs and there is a problem in color overlay accuracy.

As one of the technical problems for improving the quality of color hard copy, Y (yellow), M (magenta),
Color overlay accuracy of each toner of C (cyan) and BK (black) can be mentioned. Poor color overlay accuracy causes problems such as color reproduction and color unevenness. In the conventional method using a plurality of photosensitive drums or belts, the color superposition accuracy is 150 due to variations in the scanning position of the writing beam and variations in the transfer position of the toner image.
The limit was about μm. This factor was caused by variations in the precision of mechanical elements such as gear belts and pulleys, and variations in the electrical timing such as writing start and transfer start.

[0005]

An object of the present invention is to provide a color recording apparatus which has been made in view of the above-mentioned circumstances, and which mainly prevents color misregistration, blurring, and transfer blurring during transfer to obtain a high-quality image. It was made for that purpose.

[0006]

In order to achieve the above object, the present invention provides (1)
The toner image formed from the color-separated image signals for each color on the image carrier is conveyed to the transfer paper that is electrostatically attracted to the dielectric film or belt in synchronization with the linear speed of the image carrier. In an electrophotographic color recording apparatus that obtains a color image by performing a transfer, a transfer paper ironing device is provided immediately before the transfer position of the toner image on the suction side of the transfer paper, facing the dielectric film or belt. Further, (2) the transfer paper squeezing device is composed of a roller member, can be brought into contact with and separated from the dielectric film or the belt, and applies a frictional load in a pulling direction toward the rear end side of the transfer paper. (3) In (1) or (2) above, in the roller member of the transfer paper ironing device, a core material is connected to a high-voltage power source, and a conductive rubber is used as a charge supply layer outside the core material. Is covered It is obtained by said being. Hereinafter, description will be given based on examples of the present invention.

FIG. 1 is a block diagram for explaining an embodiment of a color recording apparatus according to the present invention. In the figure, 1 is a scanner unit, 2 is an optical writing unit, 2a is a polygon mirror, and 2b is an image formation. Lens (fθ lens), 2c bending mirror, 3 photoconductor drum, 4 charger, 5 BK (black) developing device, 6 C (cyan) developing device, 7 M (magenta) developing device, 8 Is a Y (yellow) developing device, 9 is a photoconductor cleaner, 10 is a transfer drum, 11 is a transfer drum cleaner, 12 is a transfer charger, 13 is a separation charger,
Reference numeral 14 is a separating claw, 15 is a fixing device, 16 is a transfer paper, 17 is a clamper, and 18 is an ironing roller.

On the transfer paper 16 which is electrostatically adsorbed and wound on the transfer drum 10, a toner image formed from color-separated image signals separated into respective colors on the photoconductor drum 3 is formed on the photoconductor. A color image is obtained by sequentially superposing and transferring at the contact position between the drum 3 and the transfer drum 10. The transfer paper 16 fed from the paper supply unit is transferred to the clamper 17 on the transfer drum 10.
The tip is gripped by and is electrostatically attracted and wound by the transfer charger 12 on the dielectric film 19 (FIG. 2). At that time, the winding step is performed in a state where the photoconductor drum 3 and the transfer drum 10 are in contact with each other, but the winding of one rotation may cause incomplete contact between the dielectric film 19 and the transfer paper 16. Then, after exposure and development, in the process of transferring the toner image formed on the photoconductor drum 3 to the transfer paper 16, transfer defects such as white spots or image blurring occur.

Further, when the color toner images of four colors are superposed and transferred, as shown in FIG. 3, there is a difference in the amount of color misregistration depending on the presence or absence of the ironing mechanism. In particular, there is a tendency that a large color misregistration occurs when transferring the first color to the second color, and after the third color, the colors are overlapped at the position of the second color. This is because the adhesion between the dielectric film of the transfer drum 10 and the transfer paper 16 becomes stable every time the transfer process is repeated. The present invention pays attention to this point, and in the winding process of the transfer paper, the squeezing roller 1 is provided between the position of the clamper 17 and the transfer position.
8 is arranged, and a contact / separation mechanism is provided so that the ironing roller 18 and the transfer drum 10 are contacted with each other only during the winding step.

FIGS. 4 (a) and 4 (b) are structural views of the drive portion of the photosensitive drum and the transfer drum, FIG. 4 (a) is a plan view, and FIG. 4 (b) is a side view. In the figure, 20a and 20b are frames and 2
1 is a photoconductor drive motor, 22 is a coupling, 23 is a transfer drum motor (drum in motor), 24a (24b)
Is a swing lever, 25 is an eccentric cam, and 26 is a drive motor. The photoconductor drum 3 is directly driven by the photoconductor drive motor 21 via the coupling 22. Further, the transfer drum 10 is driven by a transfer drum motor 23 arranged inside the transfer drum. The transfer drum motor 23
The shaft is fixed, and the outer rotor and the frames 20a and 20b rotate integrally. The transfer drum 10 is brought into and out of contact with a swing lever 2 that rotatably locks the transfer drum.
4a (24b) is rocked using the eccentric cam 25.

FIG. 5 is a block diagram of the ironing roller.
27 is a compression spring. The squeezing roller 18 has a compression spring 27 fitted to one end of a longitudinal axis thereof and a swing lever 24.
A predetermined friction torque can be obtained by holding a and 24b.

According to the above-described embodiment, the transfer paper 16 sent from the feeding portion has its leading end gripped by the clamper 17, and when it rotates, it crosses the ironing roller 18. The transfer paper 16 receives the pressure force of the ironing roller 18 and the tangential force in the rear end direction to enhance the adhesion with the dielectric film 19, and the transfer charger 12 electrostatically adsorbs the adhesion while maintaining the adhesion. When the winding process of the transfer paper is completed, the ironing roller 18 is moved away from the transfer drum 10 by swinging the swing levers 24a and 24b by the eccentric cam 25.
After that, exposure, development, and transfer are repeated for each color to obtain a full-color image.

FIG. 6 is a diagram showing another embodiment of the color recording apparatus according to the present invention, in the case of using a photosensitive belt. In the figure, 31 is a scanner unit, 32 is an optical writing unit, 33 is a photoconductor belt, 34 is a charging device, 35 is a developing unit, 35a to 35d are developing devices, 36 is a neutralization device, 37 is a cleaner, and 38 is neutralization. Device, 39a, 39b
Is a photoconductor belt driving roller, 40 is a fixing device, 41 is a paper feeding device, 42 is an ironing roller, 43 is a transfer paper transport belt, 44 is a transport belt drive roller, and 45 is a roller.

An image of each color is formed on the photoconductor belt 33, and these images are transferred onto the transfer paper on the transfer paper conveying belt 43 so as to form a color image, and the transfer paper conveying belt 43 is conveyed. When the image of each color is transferred by the belt driving roller 44, the photosensitive belt 33 is rotated in the forward direction in synchronization with the rotation of the photosensitive belt 33, and is switched back by the reverse rotation until the transfer of the next color image. Even in this method, poor adhesion between the transfer paper and the transfer paper transport belt 43 causes color misregistration.

FIG. 7 is a partially enlarged view of FIG.
Is a swing lever, 52 is a solenoid, 53 is a swing lever,
54 is a solenoid. Immediately before the transfer charger 36, a pair of conductive rubber rollers 42 (ironing rollers), 45
A transfer belt switching roller (also used as a transfer belt switching roller) is arranged to electrostatically adsorb the transfer paper conveyed from the paper feeding section to the transfer paper conveyance belt 43 by roller charging. Pair of conductive rubber rollers 42, 4
By electrostatically adsorbing while applying pressure by 5, and further applying a frictional load to the rear end side of the transfer paper by the ironing effect of the roller, the adhesion is improved.

In the transfer paper suction mode, the swinging lever 51 of the ironing roller is rotated clockwise by the solenoid 52 to give an appropriate pressure, and the swinging lever 53 of the transfer belt switching roller 45 is rotated counterclockwise. It is in a state of being
At the time of transfer, the swing lever 51 of the ironing roller 42 rotates counterclockwise to be sufficiently away from the transfer paper transport belt 43, and the swing lever 53 of the transfer belt switching roller rotates clockwise to transfer the transfer paper. The transport belt 43 is lifted upward, and the transfer paper and the photoconductor belt 33 are brought into contact with each other, and the transfer is performed. Further, at the time of switchback, the toner image is separated from the photosensitive belt 33 and the squeezing roller 42 is kept in the escaped state, so that the toner image before fixing is not disturbed.

[0017]

[Effect] As is apparent from the above description, the present invention has the following effects. (1) Since the adhesion between the transfer paper and the dielectric film is improved by a mechanical ironing device, the adhesion failure due to curling of the transfer paper is prevented, and a high-quality color image without white spots, blurring, or color misregistration is obtained. Obtainable. (2) By applying friction torque to the ironing roller with a simple structure, it can be applied to any system of the photoconductor drum and the photoconductor belt, and a high quality color image can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of a color recording apparatus according to the present invention.

FIG. 2 is a configuration diagram of a transfer drum.

FIG. 3 is a diagram showing the presence or absence of an ironing mechanism and the amount of color misregistration.

FIG. 4 is a configuration diagram of a driving unit of a photosensitive drum and a transfer drum.

FIG. 5 is a configuration diagram of an ironing roller.

FIG. 6 is a diagram showing another embodiment of the color recording apparatus according to the present invention.

7 is a partially enlarged view of FIG.

[Explanation of symbols]

1 ... Scanner unit, 2 ... Optical writing unit, 2a ... Polygon mirror, 2b ... Imaging lens (f.theta. Lens), 2c
… Bending mirrors, 3… photosensitive drums, 4… chargers,
5 ... BK (black) developing device, 6 ... C (cyan) developing device,
7 ... M (magenta) developing device, 8 ... Y (yellow) developing device, 9 ... Photoconductor cleaner, 10 ... Transfer drum, 11 ... Transfer drum cleaner, 12 ... Transfer charger, 13 ... Separation charger, 14 ... Separation claw, 15 ... Fixing device, 16 ... Transfer paper, 17 ... Clamper, 18 ... Ironing roller.

Claims (3)

[Claims] 1. A linear velocity of an image carrier is obtained by transferring a toner image formed from color-separated image signals separated into respective colors on the image carrier to a transfer paper electrostatically attracted to a dielectric film or a belt. In an electrophotographic color recording apparatus that obtains a color image by conveying and transferring in synchronization with the transfer, the toner image is transferred immediately before the transfer position of the toner image on the suction side of the transfer paper, facing the dielectric film or belt. A color recording device characterized by being provided with a paper ironing device. 2. The transfer paper squeezing device is composed of a roller member, can be brought into contact with and separated from the dielectric film or the belt, and applies a frictional load in a pulling direction toward a rear end side of the transfer paper. The color recording device according to claim 1. 3. The roller member of the transfer sheet ironing device,
3. The color recording apparatus according to claim 1, wherein the core material is connected to a high-voltage power source, and a conductive rubber is coated on the outside of the core material as a charge supply layer.