JPH04237082A - Color mixing preventive device of wet process color image forming device - Google Patents

Abstract

PURPOSE:To prevent the color mixing by the intrusion of an excess developer and the toners on images by spraying a developer solvent to the front of a prewetting device and flushing away the excess developer on a drum and the toners of the weak adhesive strength on the images. CONSTITUTION:The developer washing means 1 to 3 which remove the excess developer remaining on the outer peripheral surface of a transporting drum 21 and the toners of the weak adhesive strength on the images by the developer solvent and a developer solvent recovering means which recovers the developer solvent used for the developer washing means 1 to 3 are provided. The developer washing means spray the developer solvent in a developer solvent tank 4 to the transporting drum 21 by a blowing nozzle 1, a supplying pump 2 and a suction pipe 3. The developer washing means and the developer recovering means are disposed integrally with the prewetting device 43. The excess developer and the toners of the weak adhesive strength are surely removed in this way and the intrusion of such developer and toners into the developer of developing device of other colors is prevented. The exact color reproduction is thus possible without color mixing.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention involves forming an electrostatic latent image by charging and exposing photosensitive paper on a photosensitive drum or transport drum, and then supplying a developer to the electrostatic latent image to form a visible image. It relates to a wet color image forming apparatus that forms a color image by repeatedly performing an image forming process using three or four color developers, and more specifically, it relates to a wet color image forming apparatus that forms a color image by repeatedly performing an image forming process using three or four color developers. This invention relates to a color mixing prevention device for preventing color mixing.

0002

2. Description of the Related Art Conventionally, in a wet type color image forming apparatus, a conveying drum 21 holding a sheet-like photosensitive paper 20 on its outer peripheral surface is rotatably supported by a support shaft 40, as shown in FIG. The following devices are provided in order at positions facing the outer peripheral surface of the transport drum 21. First, a corona charger 41 is installed diagonally above and to the left, and applies an electrostatic charge to the sheet-like photosensitive paper 20 to charge it. Next, an exposure device 42 is installed on the left side of the conveyance drum 21, and exposes the sheet-like photosensitive paper 20 charged by the corona charger 41 to form an electrostatic latent image. Further, below the conveyance drum 21, there is a pre-wet roller 4 that contacts the sheet-like photosensitive paper 20 and prevents background smearing with developer solvent.
3, and a developing device 44 (44Y, 44M, 44C,
44B) and a drum cleaning device 45 for removing excess developer and fixed/stacked toner adhering to the outer peripheral surface of the transport drum 21. Furthermore, a static eliminator 46 is provided behind the drum cleaning device 45 for removing the charge remaining on the sheet-like photosensitive paper 20 after development.

[0003] The developing device 44 is configured to handle the sheet-like photosensitive paper 2.
0, a developing electrode 30 that supplies a developer solution, a squeeze roller 31 that removes excess developer remaining on the surface of the sheet-like photosensitive paper 20, and a developer tank 32 that stores the developer. The number of developing solutions required for color image formation (four in this conventional example) are arranged below the transport drum 21. As shown in the figure, each developing device 44 has a developing electrode 30 connected to the conveying drum 2.
1 and can be raised and lowered sequentially to opposite positions with a slight interval between them. At this time, the squeezing roller 31
It is pressed against the bottom surface of 1.

Further, on the upper right side of the conveyance drum, there is a cartridge 47 for storing a roll of photosensitive paper 52, and a cartridge 47 for storing the roll of photosensitive paper 52, which cuts the roll of photosensitive paper 52 into a desired length and transfers it to the conveyance drum 21.
Paper feed roller 48 that supplies sheet-like photosensitive paper 20 to
, a cutter 49, and a guide 50 are arranged in this order in the direction of the conveyance drum 21. A paper discharge belt 51 is disposed at the upper left side for discharging the sheet-like photosensitive paper 20 that has undergone an image forming process and has an image formed thereon.

Next, the operation of the wet color image forming apparatus will be explained.

Rolled photosensitive paper 52 inside cartridge 47
is cut into a desired length by the paper feed roller 48, cutter 49, and guide 50, and fed to the conveyance drum 21 as a sheet-like photosensitive paper 20. The outer circumference of the conveyance drum 21 is cut by a method using negative pressure or the like. held on the surface. In this state, the conveyance drum 21 is rotated in the direction of the arrow by a drive device (not shown), and at the same time, the sheet-like photosensitive paper 20 is first charged with an electrostatic charge applied to its surface by the corona charger 41. Thereafter, an electrostatic latent image is formed on the surface of the photosensitive paper 20 by an exposure device 42, and then the photosensitive paper 20 is wetted with a developer solvent by a pre-wet roller 43. Subsequently, when the sheet-like photosensitive paper 20 passes through a developing electrode 30, it is developed with a developer, and the electrostatic latent image is visualized. After development, the surplus developer remaining on the surface of the sheet-like photosensitive paper 20 is removed and collected by a squeeze roller 31. Further, the sheet-like photosensitive paper 20 is removed by a static eliminator 46 to remove the electric charge remaining on the surface.
After the color is removed, the next color process is started.

[0007] Simultaneously with the above process, a cleaning process of the transport drum 21 is performed. After the rear end of the sheet-like photosensitive paper 20 passes through the aperture roller 31 as the transport drum 21 rotates, the developing device 44 separates from the lower surface of the transport drum 21 as it moves to the next process. The rear end of the sheet-like photosensitive paper 20 is attached to a drum cleaning device 45.
, the drum cleaning device 45 comes into contact with the outer peripheral surface of the transport drum 21 and removes excess developer and adhered/stacked toner on the outer peripheral surface of the transport drum 21.

A color image can be obtained by repeating the image forming process and the cleaning process a necessary number of times, and the sheet-like photosensitive paper 20 is discharged onto the paper discharge belt 51, and all the processes are completed.

[0009]

[Problems to be Solved by the Invention] However, when developing by supplying a developer, the developer adheres not only to the photosensitive paper but also to the conveying drum, and the developer attached to the rear of the photosensitive paper is The developer attached to both sides of the photosensitive paper cannot be completely removed even if it is removed by a squeeze roller. Mixed with developer. Furthermore, among the toners on the photosensitive paper after development and passing through the aperture roller, toners with weak adhesion may peel off from the photosensitive paper during development of other colors and mix with the developer in the next process, resulting in a poor image. The problem was that it became impossible to do so.

The present invention has been made to solve the above-mentioned problems, and the problem is that the excess developer remaining on the outer peripheral surface of the conveying drum and the toner on the image are mixed into the developing device of other colors. An object of the present invention is to provide a color mixture prevention device in a wet color image forming apparatus that can prevent color mixture between liquids and obtain good images.

[0011]

[Means for Solving the Problems] In order to achieve this object, the color mixing prevention device in the wet color image forming apparatus of the present invention prevents excess developer remaining on the outer peripheral surface of the conveying drum.
and a developer cleaning means for removing weakly adhesive toner on the image with a developer solvent, and a developer solvent recovery means for recovering the developer solvent used in the developer cleaning means, The cleaning means and the developer solvent recovery means are arranged integrally with a pre-wet device that moistens the photosensitive paper with the developer solvent to prevent background smearing.

0012

[Operation] In the color mixing prevention device of the wet type color image forming apparatus of the present invention having the above-mentioned configuration, the developer cleaning means removes excess developer remaining on the outer peripheral surface of the conveying drum and toner with weak adhesion on the image. do. The developer solvent recovery means recovers the developer solvent used in the developer cleaning means.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will be described below with reference to the drawings.

The outline of the operation of the wet color image forming apparatus is the same as that of the conventional example explained using FIG. 2, so the explanation will be omitted.

FIG. 1 is a partially enlarged view of a wet color image forming apparatus equipped with a color mixture prevention device of the present invention.

A blowing nozzle 1 for blowing out the developer solvent is installed above the pre-wet roller 43 near the conveying drum. A supply pump 2 for pumping the developer solvent is connected to one end of the blow-off nozzle 1, and a suction pipe 3 for sucking the developer solvent is connected to the supply pump 2. The blowing nozzle 1 and the supply pump 2
, the developer solvent in the developer solvent tank 4 is sprayed onto the conveyance drum 21 through the suction pipe 3, and constitutes a developer cleaning means.

The developer solvent tank 4 is located below the blow nozzle 1, the supply pump 2, the suction pipe 3, and the pre-wet roller 43, and is filled with developer solvent.

Next, the operation of the color mixture prevention device in this embodiment will be explained with reference to FIGS. 1 and 2. When the image forming process starts, the roll of photosensitive paper 5 in the cartridge 47 is removed as in the conventional example.
2 is cut into a desired length by the paper feed roller 48, cutter 49, and guide 50, and fed to the conveyance drum 21 as a sheet-like photosensitive paper 20. Hold on the outer surface. In this state, the conveyance drum 21 is rotated in the direction of the arrow by a drive device (not shown), and the sheet-like photosensitive paper 20 is also rotated at the same time, and at the same time, the color mixture prevention device is activated. First, the supply pump 2 operates, and the developer solvent tank 4
The developer solvent inside is sucked in through the suction pipe 3 and is forced into the blowout nozzle 1. Then, the developer solvent is blown out from the blowing nozzle 1 onto the conveyance drum 21 . The developer solvent blown out from the blowing nozzle 1 onto the conveyance drum 21 washes away excess developer on the conveyance drum 21 or weakly adhesive toner on the photosensitive paper 20. Surplus developer on the conveyance drum 21 or photosensitive paper 20
The developer solvent that has been washed away from the upper toner with weak adhesion is then collected in the developer solvent 4 tank.

When cleaning the surplus developer on the conveyance drum 21, the developer solvent remaining on the conveyance drum moves as the conveyance drum 21 rotates, and eventually reaches the position of the drum cleaning device 45, and the developer solvent remaining on the conveyance drum moves as the conveyance drum 21 rotates. Wiped off by a cleaning roller.

Furthermore, when cleaning the toner with weak adhesion on the photosensitive paper 20, the thickness of the developer solvent remaining on the photosensitive paper 20 is made constant by the pre-wet roller 43. At this time, the photosensitive paper 20 is washed and moistened by the developer solvent to prevent scumming. Next, when passing through a developing electrode 30 in a developing device, the electrostatic latent image is developed with a developer to become a visible image, and then sent to a squeeze roller 31 . After removing the excess developer remaining on the surface of the sheet-like photosensitive paper 20, the squeezing roller 31 separates from the outer peripheral surface of the conveying drum 21 as the developing device 44 moves to the next process. When the squeezing roller 31 separates from the conveying drum 21, the excess developer remaining in the wedge-shaped gap formed between the conveying drum 21 and the squeezing roller 31 remains on the outer peripheral surface of the conveying drum 21. The surplus developer remaining on the outer peripheral surface of the transport drum 21 adheres to the outer peripheral surface of the transport drum 21 as the transport drum 21 rotates, reaches the drum cleaning device 45, and is removed.

A color image can be obtained by repeating the image forming process and the cleaning process a necessary number of times, and the sheet-like photosensitive paper 20 is discharged onto the paper discharge belt 51, and all the processes are completed.

That is, by operating the developer cleaning means and developer recovery means of the present invention after each color is developed, it is possible to remove excess developer that adhered to the conveying drum during development and toner with weak adhesion on the photosensitive paper. .

[0023] In the developer solvent tank 4, it is also possible to incorporate an electrodeposition device in the developer solvent tank 4 to remove the removed toner by electrodeposition and to keep the developer solvent clean at all times.

The present invention is not limited to the embodiments detailed above, and various changes can be made without departing from the spirit thereof. In the present invention, the developer solvent is washed by blowing it out of the nozzle, but the developer solvent for cleaning may be supplied by pumping up a large amount of the developer solvent by the pre-wet roller itself. In addition, in this embodiment, the image forming process was explained, but
It is also possible to improve the cleaning effect of the transport drum 21 by operating the developer cleaning means at times other than during the image forming process.

[0025]

[Effect of the invention] As is clear from the detailed description above,
According to the present invention, surplus developer remaining on the outer circumferential surface of the conveying drum and toner with weak adhesion on the photosensitive paper are reliably removed, and the developer of another color developing device is replaced in preparation for the next process. Contamination can be prevented, and accurate color reproduction is possible without color mixing between the developer solutions of each color.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment embodying the present invention, and is a partially enlarged view of a wet color image forming apparatus equipped with a color mixture prevention device.

[Figure 2] Overall schematic side view of wet color image forming apparatus

[Explanation of symbols]

1 Blow nozzle 2 Supply pump 3 Suction pipe 4 Developer solvent tank 20 Sheet photosensitive paper 21 Conveyance drum 32 Developing device 41 Corona charger 42 Exposure device 43 Pre-wet roller

Claims (2)

[Claims] Claim 1: An image forming step in which a photosensitive drum or a photosensitive paper on a transport drum is charged and exposed to form an electrostatic latent image, and then a developer is supplied to the electrostatic latent image to obtain a visible image. In a wet color image forming apparatus that forms a color image by repeatedly using three or four color developers, excess developer remaining on the outer peripheral surface of the conveying drum and toner with weak adhesion on the image are removed by development. 1. A color mixture prevention device for a wet color image forming apparatus, comprising: a developer cleaning means for removing the developer solvent with a developer solvent; and a developer solvent recovery means for recovering the developer solvent used in the developer cleaning means. 2. The present invention is characterized in that the developer cleaning means and the developer solvent recovery means are arranged integrally with a pre-wet device that moistens the photosensitive paper with the developer solvent to prevent scumming. The color mixture prevention device in the wet color image forming apparatus according to item 1.