JPH02306277A - Toner image transfer mechanism - Google Patents

Abstract

PURPOSE:To shorten the operating time and to reduce transfer irregularity by providing a transfer plate and a link mechanism transmitting drive to the transfer plate. CONSTITUTION:When the rotation of a photosensitive drum 1 is controlled to a prescribed speed, an electrostatic latent image is written with a laser beam 13. When a toner image moves close to a transfer position, a tractor 8 is driven, and a recording medium 6 is accelerated to a prescribed speed. When the speed of the recording medium is made equal to that of the drum 1, a DC motor 4 is driven to operate the transfer plate 2 via a link 3, and the drum 1 is brought into contact with the recording medium 6. Simultaneously, a voltage is applied to a transfer unit 9, and the toner image is transferred onto the recording medium 6. At the end of a printing action, the similar procedures are carried out reversely. In this configuration, the transfer plate 2 can be turned on/off at 20msec or below, and brake is applied to the DC motor with a reverse voltage, thereby reducing a shocking sound produced in operation. The operational angle of the DC motor is set to 180 deg., and the link 3 is used, whereby the play of the transfer plate can be reduced.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a toner image transfer mechanism, and particularly to a toner image transfer mechanism for transferring a toner image formed on a photosensitive drum of an electrophotographic printer to a recording medium such as continuous form paper. It relates to an image transfer mechanism.

[Conventional technology]

Conventionally, this type of toner image transfer mechanism has been constructed using a rotary solenoid and a link mechanism.

FIG. 6 is a configuration diagram of a toner image transfer mechanism portion for explaining an example of such a conventional method.

As shown in FIG. 6, in the conventional transfer mechanism, an intermediate link 22 is connected to a drive shaft 21 of a DC rotary solenoid, and a transfer plate 23 is connected to the other end of this intermediate link 22. During the transfer operation, the transfer plate 23 is in contact with the photosensitive drum (not shown), but the transfer plate 23 is in contact with the intermediate link 2 even during the transfer operation.
2 is in contact with the photosensitive drum.

[Problem to be solved by the invention]

The conventional toner image transfer mechanism described above uses a rotary solenoid as a driving source, so there is a limit to its operating speed.
Moreover, since the operating angle is determined, there is no degree of freedom in the link configuration, and there is a drawback that the influence of link rattling is large.

Further, unlike a DC motor, the rotary solenoid in the conventional toner image transfer mechanism cannot be braked by the applied voltage, so there is a drawback that the rotary solenoid is unstable during operation.

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner image transfer mechanism that can shorten the operating speed, reduce the squeaks and squeaks that occur during production, and reduce transfer blur.

[Means to solve the problem]

The toner image transfer mechanism of the present invention includes a transfer plate that brings a recording medium into contact with a photosensitive drum, and a link mechanism that transmits information to the transfer plate.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a toner image transfer mechanism showing an embodiment of the present invention.

As shown in FIG. 1, the toner image transfer mechanism of this embodiment is as follows:
A transfer plate 2 that brings the recording medium 6 into contact with the photosensitive drum 1
, a DC motor 4 that drives the transfer plate 2 , and a link arm 3 that transmits the drive of the DC motor 4 to the transfer plate 2 . The recording medium 6 is run by a bin tractor 8, and the running surface is formed by a paper guide 5, a shirt door, and a transfer plate 2.

Further, during the printing operation, the recording medium 6 is in contact with the photosensitive drum 1, and the charged toner 10 is transferred to the recording medium 6 at a transfer point 11 by the electric field generated by the transfer device 9. At this time, the speeds of the photosensitive drum 1 and the recording medium 6 are controlled to be constant. Note that 12 is a phenomenon device, and 13 is a laser beam.

On the other hand, if a speed difference occurs when the printing operation is started or when the printing operation is stopped, and the surface of the photosensitive drum 1 and the recording medium 6 rub against each other, the image may be smudged by uncharged toner existing on the drum surface, or the recording medium 6 may be damaged due to friction. The transferred image may become blurred.

FIG. 2 is an enlarged view of the vicinity of the transfer plate shown in FIG. 1.

As shown in FIG. 2, in order to prevent the recording medium 6 from becoming blurred, in this embodiment, the transfer plate 2 is separated from the photosensitive drum 1 except during the transfer operation, so that the recording medium 6 is exposed to the photosensitive drum 1. It is made so that it does not come into contact with drum 1.

FIG. 3 is an operation timing diagram of the rotating drum, recording medium, etc. shown in FIG. 1.

As shown in FIG. 3, at the time of starting the printing operation, the rotational speed of the photosensitive drum 1 first increases and when it reaches a specified speed, it is controlled to a constant speed. Next, writing of an electrostatic latent image using the laser beam 13 is started, and the developing device 12 starts forming a toner image. When this toner image approaches the transfer point, the bin tractor 8 is driven to accelerate the recording medium 6 to a predetermined speed. Thereafter, when the speed of the recording medium 6 becomes equal to that of the photosensitive drum 1, the transfer plate 2 is operated to bring the photosensitive drum 1 into contact with the recording medium 6. At this time, a voltage is simultaneously applied to the transfer device 9 to transfer the toner image onto the recording medium 6. Furthermore, this can be realized by performing the same procedure in reverse when the printing operation is finished.

During the time period 14 from the start of the running of the recording medium 6 to the end of the operation of the transfer plate 2 in the above transfer operation, normal toner image transfer is not performed.

This is called the so-called non-transferable time.

Therefore, the distance (referred to as X) that the recording medium 6 travels during the transfer impossible time 14 remains on the medium as an unprintable margin. In order to reduce this distance X, it is necessary for the transfer plate 2 to operate in a short time.

FIGS. 4(a) and 4(b) are diagrams showing printing stop and start operations of the link mechanism and transfer plate shown in FIG. 1, respectively.

It is shown as the amount of movement.

Such a DC motor starts rotating at a constant acceleration when a forward voltage is applied, and shifts to decelerated rotation at a constant acceleration and stops when a reverse voltage is applied. At this time, the transfer plate rotates with greater acceleration via the link arm.

That is, as can be seen by comparing FIGS. 5(a) and 5(b), the time taken to move the transfer plate appears to be shorter than the time taken for the DC motor to rotate. However, this is due to the structure of the link mechanism, and the transfer plate is B1
The operation is almost completed in the time from 82 to 82.

〔Effect of the invention〕

As explained above, the toner image transfer mechanism of the present invention has D
20m5eC by driving by C motor
It is possible to turn the transfer plate ON or OFF in the following short time, and furthermore, by applying a brake using a reverse voltage, it is possible to reduce shock noise during operation.

Further, the toner image transfer mechanism of the present invention uses a link mechanism to
By setting the operating angle of the C motor axis to 180°,
This has the effect of reducing rattling of the transfer plate due to rattling of the links.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a toner image transfer mechanism showing an embodiment of the present invention, FIG. 2 is an enlarged view of the vicinity of the transfer plate shown in FIG. 1, and FIG. 3 is a rotating drum and recording medium shown in FIG. 1. Fig. 4, camellia (a). (b) is a configuration diagram of a toner image transfer mechanism portion for explaining an example of a mechanism showing printing stop and start operations of the link mechanism and transfer plate shown in FIG. 1, respectively. 1...Photosensitive drum, 2...Transfer plate, 3...Link arm, 4...DC
Motor, 5...Paper guide, 6...
・Recording medium, 7...Shaft, 8...
Bin tractor, 9...Transfer machine, 10...
・Toner, 11...Transfer point, 12...
...Developer, 13...Rede light, 14...
...Transfer impossible time.

Claims (1)

[Claims] A toner image transfer mechanism comprising: a transfer plate that brings a recording medium into contact with a photosensitive drum; and a link mechanism that transfers information to the transfer plate.