JP3659382B2 - Transfer device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transfer device that transfers a toner image formed on an image carrier onto a recording material to be conveyed.
[0002]
[Prior art]
The prior art will be described with reference to FIGS. In FIG. 2, the surface of the photosensitive drum 1 passes through a charger and an exposure scanning device (not shown), whereby an electrostatic latent image is formed on the surface. The electrostatic latent image is visualized as a toner image by the developing device 2. The toner image formed on the photosensitive drum 1 is transferred onto the continuous paper 5 conveyed by the conveying tractor 4 by the transfer device 3. Thereafter, the continuous paper 5 is sent to the fixing device 6 where the toner image is fixed and discharged.
[0003]
A transfer device 3 of a printing apparatus using such continuous paper as a recording medium generally has a retractor 3b for bringing the continuous paper 5 into close contact with the photosensitive drum 1 and a toner image formed on the photosensitive drum 1 onto the continuous paper 5. And a transfer device 3a for transferring.
[0004]
The transfer unit 3a is fixed to the surface of the photosensitive drum 1 at a predetermined distance. Further, the retractor 3b approaches the photosensitive drum 1 so that the continuous paper 5 is in close contact with the photosensitive drum 1 only during printing, and is away from the photosensitive drum 1 so that the continuous paper 5 does not contact the photosensitive drum 1 when not printing. Is provided with an operating mechanism that is spaced apart from each other.
[0005]
As shown in FIG. 3, the retractor 3b is provided with a hinge 9 serving as a center of rotation, and as an operating mechanism of the retractor 3b, the retractor 3b is connected by a movable arm 10 to a motor 12 to which an eccentric shaft 11 is attached. . By the rotation of the motor 12, the retractor 3b moves up and down with the hinge 9 as a fulcrum and maintains the position with the photosensitive drum 1.
[0006]
Since the transfer device 3 transfers the toner image on the photosensitive drum 1 to the continuous paper 5, the relative position between the retractor 3b and the photosensitive drum 1 during printing must always be constant. When the stop position of the retractor 3b during printing is fluctuated, the print density may be uneven or the printing itself may be chipped. The stop position of the retractor 3b is very important. Therefore, the sensor 13 is provided so that the stop position of the retractor 3b during printing is always constant, and the sensor 13 controls and manages the stop position.
[0007]
[Problems to be solved by the invention]
However, the retractor 3b is constantly vibrated because the continuous paper 5 is pulled and conveyed at a certain tension or more on the retractor 3b so as not to be loosened. This vibration is also affected by the difference in paper quality such as the amount of continuous paper. When the vibration is large, the printing density is uneven as described above, or the printing itself is chipped.
[0008]
An object of the present invention is to provide a transfer device that can solve the above-described problems and can realize stable toner image transfer with an inexpensive configuration.
[0009]
[Means for Solving the Problems]
A transfer device for transferring a toner image formed on an image carrier to a recording material to be conveyed, the transfer device provided facing the surface of the image carrier, and installed behind the transfer device. And a retractor that extends from the base and has a recording material guide portion provided upstream and downstream in the recording material conveyance direction with respect to the transfer device, and a retractor that causes the retractor to approach / separate from the image carrier In the transfer device including the moving means, the elastic member is provided between the back surface of the transfer device and the base portion facing the back surface.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to FIG. In addition, the same code | symbol is attached | subjected about the member similar to FIG. 3, and the description is abbreviate | omitted.
[0011]
Reference numeral 1 denotes a photosensitive drum serving as an image carrier, and 3 denotes a transfer device that transfers a toner image on the photosensitive drum 1 onto a sheet 5 to be conveyed. The transfer device 3 includes a transfer device 3a provided opposite to the surface of the photosensitive drum 1, and a retractor 3b. Here, the retractor 3b includes a base portion 31 installed behind the transfer device 3a, and guide portions 32 and 33 extending from the base portion 31 and provided upstream and downstream in the sheet transport direction with respect to the transfer device 3a. Yes.
[0012]
In the present invention, the elastic member 14 is provided between the back surface of the transfer device 3a and the base portion 31 facing the back surface. The elastic member 14 is configured by, for example, a leaf spring, one end is fixed to the back surface of the transfer device 3 a, and the other end is provided as a free end that can contact the base portion 31.
[0013]
In the above configuration, the retractor 3b is spaced apart from the photosensitive drum 1 so that the paper 5 does not contact the photosensitive drum 1 when not printing. At the start of printing, the retractor 3 b is raised to bring the paper 5 into close contact with the photosensitive drum 1. At this time, the elastic member 14 fixed to the transfer device 3a contacts the base 31 of the retractor 3b. The retractor 3b is given a constant load by the elastic member 14. Since the retractor 3b is subjected to a load, the vibration when the paper 5 is conveyed is absorbed by the elastic member 14. Therefore, stable holding of the retractor 3b is realized without being affected by the difference in paper quality such as the continuous amount of paper.
[0014]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a transfer device capable of realizing stable toner image transfer with an inexpensive configuration.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a transfer apparatus of the present invention.
FIG. 2 is a schematic configuration diagram of a printing apparatus.
FIG. 3 is a cross-sectional view of a conventional transfer device.
[Explanation of symbols]
1 is a photosensitive drum (image carrier), 3 is a transfer device, 3a is a transfer device, 3b is a retractor, 5 is continuous paper (recording material), 31 is a base, 32 and 33 are guide portions, and 14 is an elastic member. .

Claims (2)

A transfer device for transferring a toner image formed on an image carrier to a recording material to be conveyed, the transfer device provided facing the surface of the image carrier, and installed behind the transfer device. And a retractor that extends from the base and has a recording material guide portion provided upstream and downstream in the recording material conveyance direction with respect to the transfer device, and a retractor that causes the retractor to approach / separate from the image carrier A transfer device comprising a moving means;
A transfer apparatus comprising an elastic member between a back surface of the transfer device and the base portion facing the back surface. The transfer apparatus according to claim 1, wherein one end of the elastic member is fixed to a back surface of the transfer unit, and the other end is provided as a free end capable of contacting the base.

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