JPH01251069A - Transfer device - Google Patents

Abstract

PURPOSE:To optimize an image by using two motors of a high precision motor and a high torque motor, rotating a photosensitive drum by means of the high precision motor when a toner image is formed and rotating the photosensitive drum and a transfer drum by means of the high torque motor when the toner image is transferred. CONSTITUTION:When the toner image is formed, the transfer drum 8 is separated from the photosensitive drum 2 and the photosensitive drum 2 is rotated by means of the high precision motor 4. When the toner image is transferred to an image receiving sheet, the transfer drum 8 is made to press-contact with the photosensitive drum 2 and both the drums 2 and 8 are rotated by means of the high torque motor 7. Thus, when the toner image is transferred, stable transferring can be achieved by securing a necessary high torque. When the toner image is formed, the rotating precision of the photosensitive drum 2 is heightened, thereby obtaining an appropriate toner image without irregularity.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention develops an electrostatic latent image obtained by electrophotography or electrostatic recording to obtain a toner image, and transfers the toner image to an image receiving sheet. The present invention relates to a transfer device that performs transfer.

<Prior art and its problems> Conventionally, an electrostatic latent image is formed by irradiating a −-like charged photoconductor with a light beam modulated based on an image signal that carries a continuous tone image, and then Image recording methods are known in which a hard copy of the image is formed by a conventional electrophotographic process.

Furthermore, various electrophotographic methods have been proposed in the past that allow continuous-tone images to be recorded with good gradation reproducibility. For example, in Japanese Patent Publication No. 49-38172 by the present applicant, after an electrostatic latent image formed on a photoconductor is developed into a toner image using a liquid developer (developing solution), this toner image is adhered (adhesive).
An electrophotographic process is disclosed in which a tape is crimped to remove the toner image and the tape is then adhered to a final support.

The above developer is made by dispersing fine toner particles with an electric charge in an insulating liquid, and the toner particle diameter is usually 0.1 to 1.0 μm, which is smaller than that of a dry developer. , which is advantageous for recording continuous tone images.

As a method of transferring the toner image formed on a photoconductor to a support such as paper, electrostatic transfer using a corotron is widely used. There is a problem in that the transfer efficiency is poor between high-density areas and low-density areas. On the other hand, the so-called adhesive transfer method in which a toner image is transferred to the adhesive layer described above has a transfer efficiency of nearly 100% regardless of the image density, and is therefore also advantageous for recording continuous tone images.

On the other hand, various methods of recording color images using electrophotography have been proposed. This color image recording method basically forms electrostatic latent images on a photoconductor as described above based on three or four color image signals, and each time each electrostatic latent image is formed, Then, it is developed into color toner images of individual colors corresponding to the image signals, and these color toner images of different colors are sequentially aligned and transferred onto a sheet of transfer paper.

If the above-mentioned wet development method and adhesive transfer method are applied to such a color image recording method, a color continuous tone image with excellent gradation reproducibility can be recorded. That is,
Color toner images of different colors obtained by wet development are
If you transfer the toner onto an adhesive image-receiving sheet pressed against the photoconductor and repeat this operation three or four times for each image-receiving sheet, that is, for the number of color toner images, a color image will be recorded on the image-receiving sheet. be able to.

In addition, the color toner images obtained by the above-mentioned wet development method are adhesively transferred to separate transparent image-receiving sheets for each color, and the thus obtained three or four transparent sheets each carrying a color toner image of a different color are used. A color image recording method has also been disclosed in which image-receiving sheets are adhesively laminated via respective adhesive layers (Japanese Patent Application No. 73750/1983).

A conventional apparatus for forming a toner image and adhesively transferring the toner image to an image receiving sheet in these methods will be described with reference to FIG.

In the apparatus shown in FIG. 3, a photoconductor 11 is provided on the outer peripheral surface 2a.
The photosensitive drum 2 provided with the photosensitive drum 1 is rotated in the direction of the arrow by a high torque motor, and a toner image is formed on the outer circumferential surface 2a by a toner image forming means 120 disposed facing the outer circumferential surface 2a. . This toner image forming means 120 includes a charger 121, an exposure section 122, a developing device 123, and a charger 121, an exposure section 122, a developing device 123, and
Drying means 124, static eliminator 125, cleaning roller 1
26, a cleaning blade 127, etc., and the photoconductor 111, which is uniformly charged by the charger 121, rotates the photosensitive drum 2 (sub-scanning) and deflects and irradiates the light beam 122b in the exposure section 122 (main-scanning). ) is scanned two-dimensionally by the light beam 122b to form an electrostatic latent image, and then this electrostatic latent image is wet-developed by the developer 123 to obtain a toner image. It is dried by a drying means 124 such as.

On the other hand, the transfer drum 8 moves eight times in the direction of the arrow B1, and has a position where it presses against the photoconductor 111 on the outer circumferential surface of the photosensitive drum, and a position B2
The image-receiving sheet supplying means 13, which will be described later,
0, the supplied image-receiving sheet 101 is transferred to the transfer drum 8 with its adhesive surface facing outward (towards the outer peripheral surface of the photosensitive drum 2).
wrapped around. Note that the image receiving sheet supply means 130
An image-receiving sheet supply roller 131 that winds and stores a transparent image-receiving sheet 101 having a belt-shaped release paper or release film 102 adhered to its adhesive surface, and a release paper or Nip roller 1 that pinches the image receiving sheet 101 with a release film
32A, 132B and their nip rollers 132A, 13
Image-receiving sheet 10 at the position sandwiched by 2B! It consists of a release paper or release film winding roller 133 that winds up the release paper or release film 102 peeled off from the release paper or release film 102 .

When it is detected or determined that the toner-developed portion on the photoconductor 111 has been conveyed to just before the position facing the transfer drum 8, the transfer portion that had been detached from the photosensitive drum 2 until then is The drum 8 (wrapped with the image receiving sheet 101 from which the ml pattern paper or the release film 102 has been peeled off) moves in the 81 direction so as to press against the photosensitive drum 2 at a position P1. As the transfer drum 8 moves in this manner and comes into pressure contact with the photosensitive drum 2, the transfer drum 8 rotates as a result of the photosensitive drum 2, and the image receiving sheet lO1, which has been wrapped around the outer peripheral surface 8a, has its adhesive surface side photoconductive. It is continuously pressed against the body 111.

In this way, the toner image formed on the photoconductor 111 is adhesively transferred to the adhesive surface of the image receiving sheet 1o1.

When the transfer is completed, the transfer drum moves in the B2 direction and separates from the photosensitive drum 2.

Thereafter, the image receiving sheet 101 to which the toner image has been transferred is bonded to the support sheet 104 sent out from the support sheet supply roller 141 between the pressure rollers 140A and 140B, and further cut by the cutter 142.
By the way, in the above-described adhesive transfer, if uneven rotation of the photosensitive drum 2 occurs, the resulting toner image will be uneven due to fluctuations in the sub-scanning speed in the exposure section 122 and uneven development time. arise.

In this regard, the conventional adhesive transfer device described above has the following drawbacks due to the drive source that rotates the photosensitive drum 2. That is, the photosensitive drum is driven and rotated by the motor 7, and the transfer drum freely rotates. However, when transferring the toner image, the transfer drum around which the image receiving sheet 101 is wrapped is pressed against the photosensitive drum 2 as described above, and the photosensitive drum is rotated by the motor 7. The rotational force of the drum 2 is transmitted to the transfer drum to rotate both drums simultaneously. In order to prevent the photosensitive drum 2 and the image-receiving sheet 101 from slipping at the position Pl, a considerably large force must be applied to resist the tension of the image-receiving sheet 101 equal to the force required to pull out the image-receiving sheet 101 from the sheet supply roller 131. It is necessary to press the photosensitive drum 2 and the transfer drum together with force, and therefore, it is necessary to use a high-torque motor as the drive source for the photosensitive drum 2 in order to rotate both drums against this large pressure force. there were.

However, because the main purpose of existing high-torque motors (e.g., induction motors, pulse motors) is to output high torque, they all have relatively poor rotational accuracy (wow and flutter -1% or more). During toner image formation, the photosensitive drum 2 rotates unevenly, resulting in the above-mentioned drawbacks.

<Objective of the Invention> An object of the present invention is to eliminate the drawbacks of the prior art described above, to improve the rotation accuracy of the photosensitive drum during toner image formation while ensuring high torque during toner image transfer, and to improve the resulting image. An object of the present invention is to provide a transfer device that can be optimized.

<Configuration of the Invention> The present invention uses two motors, a high-precision motor and a high-torque motor. When forming a toner image, the high-precision motor rotates the photosensitive drum, and when transferring the toner image, the high-torque motor rotates the photosensitive drum. The above object is achieved by rotating the transfer drum.

That is, the transfer device of the present invention includes a photosensitive drum capable of forming a toner image on its outer circumferential surface, an image receiving sheet wound around the photosensitive drum, and movable relative to the photosensitive drum so as to press against and separate from the photosensitive drum. A transfer device comprising: a transfer drum; a high-precision motor connected to a rotating shaft of the photosensitive drum; and a high-torque motor connected to a rotating shaft of the transfer drum; When the drum is separated from the photosensitive drum, the photosensitive drum is rotated by the high precision motor, and when the toner image is transferred to the image receiving sheet, the transfer drum is brought into pressure contact with the photosensitive drum, and the high torque motor rotates the photosensitive drum. This device is characterized by a configuration in which both drums are rotated.

The rotation accuracy of the high precision motor is 0.0 with wow and flutter.
It is preferably 1% or less.

Further, the maximum torque of the high torque motor is 10Kg-
It is preferable that it is C11 or more.

Forming a toner image in the present invention means exposing the outer peripheral surface of the photosensitive drum to form an electrostatic latent image, and then wet-developing this electrostatic latent image with a developer and drying it to form a toner image. This refers to all the steps from exposure to just before transfer, from exposure to light to just before transfer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the transfer apparatus of the present invention shown in the accompanying drawings will be described in detail below.

FIG. 1 is a perspective view showing a configuration example of a transfer device 1 of the present invention. As shown in the figure, the transfer device 1 includes a photosensitive drum 2, and a photoconductor 11 is disposed on the outer peripheral surface 2a of the photosensitive drum 2.
1 is provided, an electrostatic latent image is formed as described below, and the electrostatic latent image is further developed to form a toner image.

The photosensitive drum 2 has a rotating shaft 3, and a rotor of a high-precision motor 4 is connected to one end of the rotating shaft 3, and is further controlled to keep the rotational speed of the high-precision motor 4 constant. A rotary encoder 5 is installed. This high-precision motor 4 is characterized by relatively low torque but high rotational precision.

Examples include AC or DC servo motors, synchronous motors, and the like.

In the present invention, the rotation accuracy is 0.1 with wow and flutter.
It is preferable to use a high-precision motor with a wow and flutter of less than 0.1%, because if the rotational precision exceeds 0.1%, uneven scanning will occur on the image.

The transfer drum 8 has a rotating shaft 6, which is rotatably supported by U-shaped support members 9 at both ends thereof, and further has a rotor of a high torque motor 7 at one end of the rotating shaft 6. are connected. Although the high-torque motor 7 has lower rotational precision than the high-precision motor 4, it has a feature of large output torque, and examples thereof include an induction motor, a pulse motor, and a DC motor.

In the present invention, particularly when adopting an adhesive transfer method, it is preferable to use a high torque motor having a maximum torque of 10 g'cm or more. The reason for this is that if the maximum torque is less than 1.0 g'cm, the load during transfer will exceed the motor torque and drive will be stopped.

The transfer drum 8 has an image receiving sheet 101 on its outer peripheral surface 8a.
(For example, an image-receiving sheet having an adhesive layer) is wound and moved to press against and separate from the outer circumferential surface 2a of the photosensitive drum 2.

That is, a feed screw 11 rotated by a pressure contact motor 1o is attached near the center of a support member 9 that supports the transfer drum 8, and the pressure contact motor 10 is driven to rotate the feed screw in a predetermined direction. The transfer drum 8 moves in the direction of the arrow Bl or B2 in FIG. 1, and is brought into pressure contact with or separated from the photosensitive drum 2.

The pressure motor 10 is equipped with a detection plate 12 and a photosensor 13 as positioning means for detecting the state of pressure contact or separation of the transfer drum 8 or for detecting the amount of feed. Its structure is such that a detection plate is provided at the rear end of the motor shaft, and a photo sensor detects the recess or hole in the detection plate, and the position is detected by rotating the motor in the forward and reverse directions.

It goes without saying that the means for moving the transfer drum 8 is not limited to the structure described above.

Further, in the present invention, since it is sufficient that the photosensitive drum 2 and the transfer drum 8 are relatively movable, the photosensitive drum 2 may be moved in the opposite manner to the above, or the photosensitive drum 2 and the transfer drum 8 may be moved.
It may be configured such that both drums are brought into contact with each other and separated by moving the two drums, respectively.

In the configuration example shown in FIG. 1, the rotating shaft 3 of the photosensitive drum and the rotor of the high-precision motor 4, and the rotating shaft 6 of the transfer drum and the rotor of the high-torque motor are directly connected, respectively.
In the present invention, a clutch, a coupling, a joint, a reduction gear train, etc. may be interposed between these.

For example, a clutch may be interposed between the transfer drum 8 and the high-torque motor 7 to control whether or not the rotational force of the high-torque motor 7 is transmitted to the transfer drum 8. However, this clutch is not essential.

The type and structure of this clutch are not particularly limited, but it is preferable to use a clutch that can be controlled to engage or disengage from the outside, such as an electromagnetic clutch, a powder clutch,
An example is an oil clutch.

Next, the structure and operation when the transfer device 1 of the present invention is applied to a print image forming apparatus using an adhesive transfer method will be explained.

FIG. 2 is a conceptual diagram schematically showing a configuration example of a print image forming apparatus 100 loaded with the transfer device 1 of the present invention.

In an apparatus 100 shown in the figure, a photosensitive drum 2 having a photoconductor 111 provided on its outer circumferential surface 2a is rotated by a high-precision motor 4 in six directions of arrows, and toner particles are arranged facing each other along the outer circumferential surface 2a. The image forming means 120 forms a toner image on the outer circumferential surface 2a.

This toner image forming means 120 includes a charger 121 and an exposure section 122 arranged along the rotation direction A of the photosensitive drum 2.
, a developing device 123, a drying means 124, a static eliminator 125, a cleaning roller 126, a cleaning blade 127, and the like.

The exposure section 122 is, for example, a semiconductor laser, a He-Ne laser, etc.
A laser light source 122a made of a laser or the like, and a light beam (laser beam) 1 emitted from this laser light source 122a.
An optical modulator 122C, such as an AOM (acousto-optic modulator), which modulates the intensity of the optical beam 22b, a modulation circuit 122d that drives the optical modulator 122C, and a modulated optical beam 12.
2b is reflected and deflected by a polygonal mirror surface, and the outer circumferential surface 2a of the photosensitive drum is scanned in a direction substantially perpendicular to the drum rotation direction (direction of arrow A). It includes a light deflector 122e such as a polygon mirror, and a scanning lens 122f such as an fθ lens that focuses the light beam 122b to a uniform beam diameter on the outer peripheral surface 2a of the photosensitive drum.

On the other hand, the transfer drum 8 moves in the direction of arrow B1 to a position where it comes into pressure contact with the photoconductor 111 on the outer peripheral surface of the photosensitive drum, and a position B2
It can move in the direction B and take a position away from the photoconductor 111, and the image receiving sheet supplying means 13 described later
0, the supplied image-receiving sheet 101 is wound around the transfer drum 8 with its adhesive surface facing outside (If!, the outer peripheral surface side of the optical drum 2). The image-receiving sheet supply means 130 includes an image-receiving sheet supply roller 131 that winds and stores a transparent image-receiving sheet 101 having a strip of release paper or release film 102 attached to its adhesive surface; Nip rollers 132A, 132B that sandwich the released image receiving sheet 101 with release paper or release film, and the nip roller 132A
, 132B, and a take-up roller 133 that winds up the release paper or release film 102 peeled off from the image-receiving sheet 101 at a position sandwiched by the image-receiving sheet 101. , 132B.

On the downstream side of the transfer drum 8, as support sheet pasting means, there are a support sheet supply roller 141 that winds and stores the support sheet 104, and a pair that presses the support sheet 104 sent out from the support sheet supply roller 141 and the image receiving sheet 101. pressure rollers 140A, 140B and a cutter 142 are provided. These pressure rollers 140A, 1
A heat source is installed inside each of 40B, and the outer peripheral surface thereof is heated to a predetermined temperature, and each of them is rotationally driven in the direction of the arrow by a driving means (not shown).

The print image forming apparatus 100 as described above operates as follows to form a print image.

When forming a toner image on the outer circumferential surface 2a of the photosensitive drum, the pressure contact motor 10 is driven to move the transfer drum 8 in the B2 direction, and the transfer drum 8 is kept on standby at a position separated from the photosensitive drum 2. 4 to rotate the photosensitive drum 2 in the six directions of arrows. Since the photosensitive drum 2 is rotated by a high-precision motor 4 with excellent rotational accuracy, the sub-scanning speed is kept constant, so that a proper toner image without unevenness can be obtained. Furthermore, since the transfer drum 8 is separated from the photosensitive drum 2 during toner image formation, the photosensitive drum 2 can be rotated even by the high-precision motor 4 with relatively low torque.

Exposure control in the exposure section 122 is performed as follows. A digital image signal Sd representing a continuous tone image is sent from an image signal supply device 161 through a correction table 162 to a D/A converter 163, and an image signal S converted into an analog by the D/A converter 163 is subjected to the above-mentioned modulation. circuit 1
Sent to 22d. The modulation circuit 122d drives a light modulator 122c based on the image signal S, whereby the intensity of the light beam 122b is modulated in accordance with the image signal S.

As the photosensitive drum 2 rotates in the six directions of the arrows as described above, the photoconductor 111 is rotated 8 times relative to the charger 121.
At this time, the charger 121 uniformly charges the battery.

- The photoconductor 111 charged in the same manner has a laser light source 12
A light beam 122b emitted from 2a and deflected by a light deflector 122e is irradiated. This light beam 122
b is one-dimensional scanning on the photoconductor 111 by the above deflection (main scanning), and by rotating the photosensitive drum 110 in six directions, the light beam 122b is sub-scanned, and eventually the photoconductor 111 is exposed to light. It is scanned two-dimensionally by the beam 122b. As mentioned earlier, this light beam 12
2b is modulated based on the image signal S, and therefore, an electrostatic latent image of the image carried by the image signal S is formed on the photoconductor 111 irradiated with the light beam 122b.

This electrostatic latent image is developed into a toner image by a wet developer 123. This wet type developing device 123 brings a liquid developer F, which is made by dispersing fine charged toner particles in an insulating liquid, into contact with the photoconductor 111, and causes the toner particles to be attached to the photoconductor 111 by electrostatic attraction. By attaching
The electrostatic latent image is developed with toner.

The toner image thus formed is produced by a high-intensity light beam 1.
The portion irradiated with 22b has a lower density than the other, and the gradation of the continuous tone image carried by the image signal Sd is reproduced. After this development, the photosensitive drum 2 further rotates in the direction of arrow A, and the toner image is dried by a drying means 124 such as a dryer.

On the other hand, the image receiving sheet 101 is sent out from the sheet supply roller 131 with a belt-shaped release paper or release film 102 attached thereto, and is fed to nip rollers 132A and 132B.
Release paper or release film 1 at the position sandwiched by
02 and the peeled release paper or release film 1
02 is wound up by the winding roller 133. Then, the image receiving sheet 101 from which the release paper or film 102 has been peeled off is wound around the transfer drum 8 with the adhesive side facing outward.

When it is detected or determined by any means that the toner-developed portion on the photoconductor 111 has been sent just before the position facing the transfer drum 8, the toner image is transferred. For this purpose, the drive source is switched and the transfer drum 8 is brought into pressure contact. That is, the high-precision motor 4, which had been driven up until then, is stopped, and the high-torque motor 7 is driven to rotate the transfer drum in the direction of arrow C in the figure. At the same time, the pressure contact motor 10 is driven to move the transfer drum 8, which had been detached from the photosensitive drum 2, in the B1 direction, and the second
As shown in the figure, the transfer drum 8 with the image-receiving sheet 101 wound thereon is pressed against the photosensitive drum 2 .

As the transfer drum 8 comes into pressure contact with the photosensitive drum 2 in this way, the photosensitive drum 2 rotates as a result of the transfer drum 8, and the image receiving sheet 101, which has been wrapped around the outer peripheral surface 8a of the transfer drum, has its adhesive side facing the photosensitive drum. It is continuously pressed against the photoconductor 111 on the outer peripheral surface.

In this way, the toner image formed on the photoconductor 111 is adhesively transferred to the adhesive surface of the image receiving sheet 101.

In order to perform proper adhesive transfer without slipping between the photosensitive drum 2 and the image receiving sheet 101 at the position Pl, the pressure with which the transfer drum 8 is brought into contact with the photosensitive drum 2 must be considerably large (for example, contact pressure 5k per 3001
g), but the driving source that operates during such transfer is a high-torque motor (in particular, the maximum torque of 10 and g-0
1 or more), it is possible to rotate both drums 2.8 against the contact pressure of both drums 2.8. Note that during transfer, no rotational precision is required when forming a toner image, and therefore a high-torque motor whose rotational precision is inferior to that of the high-precision motor 4 may be used as the drive source for transfer.

When the transfer is completed, the rotation of the transfer drum 8 is stopped by stopping the driving of the high torque motor 7, and the transfer drum 8 is moved in the B2 direction again and separated from the photosensitive drum 2, and is kept on standby.

The image receiving sheet 101 on which the toner image on the photoconductor 111 has been adhesively transferred is transferred to the pressure roller 140A whose outer peripheral surface is heated.
, 140B, and the support sheet 10 fed out from the image receiving sheet 101 and the support sheet supply roller 141.
4 are bonded together. The image receiving sheet 101 and the supporting sheet 104 that are stuck to each other are then cut by the cutter 142.

As described above, a toner image is recorded as a continuous tone image on the support sheet 104 which is a support, and a printed image is obtained with the transparent image receiving sheet 101 that functions as a protective layer for the toner image being adhered thereon. .

Note that after the toner image has been adhesively transferred to the image receiving sheet 1o1, the photoconductor 111 is neutralized by a static eliminator 125.
Further, it is cleaned by a cleaning roller 126 and a cleaning plate 127, and is brought into a hanging state for use in the next image recording.

Also, ON/Off of high precision motor 4 and high torque motor
The operations of F and the pressing motor 1o (pressing and separating the transfer drum 8) may be controlled by using, for example, a signal from the rotary encoder 5 as a position detecting means.

Note that the transfer device of the present invention can be applied not only to printers using the above-mentioned adhesive transfer method but also to printers using a normal electrostatic transfer method.

Furthermore, the present invention is applicable not only to monotone image recording but also to three-dimensional image recording.
It can also be applied to a color image recording method (for example, Japanese Patent Application No. 73750/1983) in which toners of one color or four colors are replaced one after another.

<Effects of the Invention> The transfer device of the present invention includes a high-precision motor that rotates the photosensitive drum and a high-torque motor that rotates the transfer drum, and when forming a toner image, the high-precision motor rotates the photosensitive drum and transfers the toner. By using a high-torque motor to rotate the transfer drum and photosensitive drum during image transfer, the necessary high torque is ensured during transfer to enable stable transfer, and the rotation accuracy of the photosensitive drum is increased during toner image formation. , it is possible to obtain a proper toner image without unevenness.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a preferred configuration example of the transfer device of the present invention. FIG. 2 is a conceptual diagram schematically showing a configuration example of a print image forming apparatus using an adhesive transfer method, in which the transfer device of the present invention is loaded. FIG. 3 is a conceptual diagram schematically showing the configuration of a print image forming apparatus using a conventional adhesive transfer method. Explanation of symbols 1... Transfer device, 2... Photosensitive drum, 3... Rotating shaft, 4... High precision motor, 5... Rotary encoder, 6... Rotating shaft, 7... High torque motor, 8... Transfer drum, 9... Support member, 10... Pressure contact motor, 11... Feed screw, 12... Detection plate, 13... Photo sensor, 100... - Print image forming device, 101... Image receiving sheet, 102... Release paper or release film, 104...
- Support sheet, 111... Photoconductor, 120... Toner image forming means, 121... Charger, 122... Exposure section, 123... Developing device, 124... Drying means, 125 ... Static eliminator, 126... Cleaning roller, 127... Cleaning blade, 130... Image receiving sheet supply means, 131... Image receiving sheet supply roller, 132A, 132B... Nip roller, 133...
Winding roller, 140A, 140B... Pressure roller, 141... Support sheet supply roller, 142... Cutter, 161... Image signal supplier, 162... Correction table, 163... D/ A converter 12□ノ'

Claims (1)

[Claims] (1) a photosensitive drum capable of forming a toner image on its outer peripheral surface; a transfer drum around which an image-receiving sheet is wound; and movable relative to the photosensitive drum so as to press against and separate from the photosensitive drum; and the photosensitive drum. A transfer device comprising: a high-precision motor connected to a rotating shaft of a drum; and a high-torque motor connected to a rotating shaft of the transfer drum, wherein when forming a toner image, the transfer drum is moved away from the photosensitive drum. At the same time, the photosensitive drum is rotated by the high precision motor, and when the toner image is transferred to the image receiving sheet, the transfer drum is brought into pressure contact with the photosensitive drum, and both drums are rotated by the high torque motor. A transfer device characterized by comprising: