JPH02264280A - Wet image forming device - Google Patents

Abstract

PURPOSE:To always obtain a satisfactory transfer image without being affected with the surface roughness of recording paper by confronting a toner image temporarily transferred onto a transfer roll with the recording paper and pressure-transferring the image onto the recording paper. CONSTITUTION:A potential difference is produced between the transfer roll 4 and the aluminum raw tube of a photosensitive drum 5 to transfer the toner image on the photosensitive drum onto a transfer drum owing to an electrostatic field. Since the face of the transfer drum is smoothed, the toner image on the photosensitive drum is faithfully transferred onto the transfer drum. Then, the transfer roll 4 abuts on the recording paper, which is pressed by a pressure roll 13, and accordingly the toner image is transferred onto the recording paper. Consequently, even the recording paper is rugged, transfer is performed with the surface of the paper smoothed by pressure. Therefore, deterioration in a transfer image due to the type of paper can be prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a method for developing a latent image formed on a drum-shaped image carrier such as electrophotography or ionography with liquid toner, and then transferring it to a recording medium such as recording paper. The present invention relates to a recording device that forms an image.

[Conventional technology]

A conventional transfer-type wet image forming apparatus is configured so that the toner image on a cylindrical carrier is brought into contact with a recording medium and transferred by an electrostatic field.

(Mochizuki et al. Changes and trends in dual-quality copying machines, Journal of the Electrophotographic Society,
26.3 (1987) pp. 270-276) [Problems to be Solved by the Invention] In the above-mentioned prior art apparatus, the problem is that the characteristics are affected by the smoothness of the recording paper in the transfer process, and high quality images cannot be obtained. It had

An object of the present invention is to solve this problem and realize an image forming apparatus that can obtain high image quality without depending on the smoothness of recording paper.

[Means to solve the problem]

The wet image forming apparatus of the present invention develops an electrostatic latent image on an image carrier with a liquid toner image and transfers it to a recording medium, and electrostatically transfers the toner image on the image carrier to an intermediate transfer medium. The toner image is transferred onto the recording paper by bringing the intermediate transfer medium into contact with the recording paper and pressing the toner image thereon.

[Effect]

In the above configuration of the present invention, the intermediate recording medium and the recording paper come into contact with each other with high pressure during transfer, so that good transfer is performed regardless of the smoothness of the surface of the recording medium.

〔Example〕

Next, the present invention will be explained based on examples. FIG. 1 is a diagram showing the configuration of a printer showing an embodiment of the present invention. The figure shows an electrophotographic printer. In the figure, recording paper (not shown) sent out from a paper feeder 1 is conveyed to a transfer position by a timing roller 2 in synchronization with the rotations of a photosensitive drum 5 and a transfer roller 4. A charging device 7 and an exposure device (laser scanner in the case of the figure) are installed around the photosensitive drum 5.
9, developing device 3, transfer drum 4, cleaning device N6,
A static eliminator 8 is provided. The recording paper onto which the toner image has been transferred is sent to a stacker 11 via a fixing device 10 by a conveyor belt 12.

In the above configuration, development is a wet development using a liquid developer in which a charged resin is dispersed in an insulating carrier liquid solvent, and the application roller 13 applies the developer in the developing device 3, and the squeeze roller 14 removes the excess developer. Remove. Photosensitive drum 15
is constructed by providing a photosensitive layer on an aluminum tube. The transcription is performed as follows. - A potential difference is provided between the transfer roller 4 and the aluminum tube of the photosensitive drum 5, and the toner image on the photosensitive drum is transferred to the transfer drum by an electrostatic field. Since the transfer drum has a smooth surface, the toner image on the photosensitive drum is faithfully transferred to the transfer drum. Since there is no need to apply pressure, the photosensitive drum will not be damaged.

Next, the transfer roller 4 and a recording paper (not shown) come into contact with each other and are pressed by the pressure roller 13, so that the toner image is transferred onto the recording paper. Therefore, since the image is transferred onto recording paper having unevenness in a smoothed state due to pressure, the transferred image does not deteriorate due to the quality of the paper unlike in the past.

Next, FIG. 2 shows only the structure of the transfer drum used in the second embodiment. The other parts are the same as those in the previous embodiment and will be omitted. It is constructed by providing rubber scraps 22 around a metal tube 21 and further providing a conductive layer 23 on the outermost periphery. The conductive layer can be created by a method of providing a resin layer containing a conductive compound on rubber, a method of plating a thin metal layer on the rubber, a method of vapor deposition, or the like. The toner image transfer between the transfer drum and the photosensitive drum is performed electrostatically as in the previous embodiment, and the toner image transfer between the transfer roller and the recording paper is performed by applying pressure. Since the transfer roller has an elastic layer, even when the smoothness of the recording paper is low, the toner image is transferred well because it is pressed by the pressure roller. That is, since the toner also comes into contact with and is transferred to the recessed portions of the recording paper, the toner image on the transfer roller is faithfully transferred onto the recording paper without leaving any portions where the toner is not transferred to the recessed portions of the surface of the recording paper.

Next, a third embodiment is shown in FIG. In this embodiment, the transfer roller is constructed by providing a conductive rubber layer 32 on a hollow metal tube 31. Since rubber has conductivity, there is no need to provide a conductive layer, and elastic pressure can be applied while providing an effective transfer electric field. Other configurations, operations, etc. are the same as in the first embodiment, and will therefore be omitted.

〔Effect of the invention〕

As described above, according to the above structure of the present invention, since the toner image once transferred to the transfer roller is transferred by pressing it while facing the recording paper, a good transferred image is obtained without being affected by the surface roughness of the recording paper. This has the effect that the following can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a printer showing an embodiment of the present invention. FIG. 2 is a sectional view of a transfer roller used in a printer according to another embodiment of the present invention. FIG. 3 is a perspective view of a transfer roller used in yet another embodiment of the invention. 21. Developing device transfer roller Photosensitive drum pressure roller 31 Metal tube elastic layer conductive layer conductive rubber layer and above Applicant Seiko Epson Corporation

Claims (1)

[Claims] In a wet image forming apparatus that develops an electrostatic latent image on an image carrier with a liquid toner image and transfers it to a recording medium, the toner image on the image carrier is electrostatically transferred to an intermediate transfer medium, and then the intermediate transfer is performed. A wet image forming apparatus characterized in that the toner image is transferred to the recording paper by bringing a medium and recording paper into contact with each other and pressing them.