JPH05188827A - Wet magnetic printer - Google Patents

Abstract

(57) [Abstract] [Purpose] To realize a magnetic printer having a simple structure capable of transferring a toner image on a magnetic drum onto a recording paper without changing the surface properties of the recording paper including the recording paper having low surface smoothness. .. To realize a magnetic printer that can stably obtain high-quality toner images. [Structure] A wet latent developer 47 is used to develop a magnetic latent image on the magnetic drum 1. The developing is an elastic developing drum 20.
With the magnetic drum 1 in contact. The magnetic drum 1 is composed of a magnetic layer 43 supported by an elastic layer 42.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic printer which forms a toner image according to a magnetic latent image on a magnetic latent image carrier and then transfers the toner image onto recording paper to obtain the toner image on the recording paper.

[0002]

2. Description of the Related Art Conventionally, various methods have been known as magnetic printers (for example, Small Blacksmith, The Electrophotographic Society of Japan, 2
6, 3, p63 (1987)).

In the first method, as a magnetic latent image carrier, a magnetic head is used to form a magnetic latent image on the outer circumference of a hard magnetic drum such as Co-Ni-P, and the latent image is developed with a dry developer. Image. The magnetic drum and recording paper are brought into contact with each other, and the toner image charged by the electrostatic field is transferred onto the recording paper. Further, the recording paper carrying the toner image is passed through a thermal pressure roller to be fixed. The structure of this device is shown in FIG. Reference numeral 41 is a magnetic drum, and 42 is a developing device.

In the second method, the toner image on the magnetic drum obtained in the same manner as in the first method is applied with pressure from the back of the recording paper which is in contact with the toner image, so that the toner image is transferred onto the recording paper and fixed at the same time. The structure of this device is shown in FIG. Reference numeral 51 is a magnetic drum, 52 is a developing device, and 53 is a transfer roller that presses the recording paper.

As a method of forming a magnetic latent image, a method of scanning a uniformly magnetized magnetic roller with a magnetic head and a method of selectively heating to obtain a magnetic latent image (USP-4458252) are known.

[0006]

The above-mentioned conventional magnetic printer has the following problems.

In the apparatus of the first system, since the development is performed magnetically and the transfer is performed electrostatically, the dry toner needs to have both magnetic characteristics and electrostatic characteristics, and it is difficult to obtain stable characteristics. Met.

The second type apparatus has a problem that the image quality at the time of transfer is deteriorated on a recording sheet having a low smoothness. Further, a large pressure is applied to the recording paper in the transfer process. Therefore, there is a problem in that the surfaces of the recording paper and the toner image that have undergone the transfer process are smoothed, have gloss, and have a poor appearance. For the same reason, there are problems that the pressure applying mechanism is complicated and wrinkles are easily generated on the recording paper during transfer.

Further, these magnetic printers have a problem that the quality of the toner image on the magnetic drum is low. In the toner image formation on the magnetic drum, the leakage magnetic field generated by the magnetization pattern selectively adsorbs the toner on the magnetic drum, and in the non-image portion, the magnetic force acts on the side facing the magnetic drum with a predetermined gap. It is carried out as follows. At this time, the magnetic flux is emphasized in the area where the toner particles (magnetic particles) are present, so that the toner is attracted in a chain shape, which deteriorates the toner image shape.

The present invention solves these problems.
It is an object of the present invention to realize a magnetic printer having a simple structure capable of transferring a toner image on a magnetic drum onto a recording paper without changing the surface properties of the recording paper. Still another object is to realize a magnetic printer which can stably obtain a high quality toner image.

[0011]

The wet magnetic printer of the present invention is a wet magnetic printer in which a magnetic latent image on a magnetic latent image carrier is developed with a wet developer and transferred to recording paper. A magnetic layer is provided on the surface of the elastic layer, and after the toner image is formed on the magnetic latent image carrier, the toner image is brought into contact with the recording sheet to transfer the toner image to the recording sheet.

Further, in a wet magnetic printer for developing a magnetic latent image on a magnetic latent image carrier with a wet developer and transferring it to a recording sheet, a drum-shaped magnetic latent image carrier is brought into contact with the magnetic latent image carrier. A magnetic latent image carrier having a drum-shaped developing drum having an elastic layer on the surface thereof, the magnetic latent image carrier is brought into contact with the developing drum, and the wet developer is supplied to the contact portion. It is constructed so that toner is adsorbed on the upper surface in accordance with the magnetic latent image for development.

[0013]

EXAMPLES Examples of the present invention will be described.

The structure of the wet magnetic printer is shown in a block diagram in FIG. A recording head 2, which is a magnetic head, a developing device 3, a transfer roller 4, a cleaning device 5, and an erasing head 6 are arranged around a magnetic drum 1 which is a magnetic latent image carrier. The magnetic drum 1 is configured to rotate in the direction of arrow A.

FIG. 2 shows the structure of the developing device 3. It has a developing drum 20 in contact with the magnetic drum 1, a peeling blade 22, and a developing head 26 for supplying a developer. Developing drum 20
Can be switched between a contact state and a released state (shown by a broken line 21). Similarly, the peeling blade 22 can be switched between the contact state and the released state. The wet developer is supplied from the developer container 24 to the developing head 26 by the pump 25 and discharged. The developer is collected from the developing device 3 in the container 23.
It is collected and stored in.

The structure of the developing head 26 is shown in FIG. The developer contained in the slit is discharged by the pressure of the pump 25.

Wet developer (hereinafter also referred to as developer)
Is a high-resistance low-dielectric-constant aliphatic hydrocarbon solvent (for example, Isopar G manufactured by Exxon Chemical Co., Ltd.) as a carrier liquid that is a dispersion medium. MAT-305 or a processed pigment obtained by coating the surface of iron oxide with a resin or the like) and toner particles composed of ethylene cellulose as a resin and an organic amine as a dispersion stabilizer.

Next, the operation will be described. In FIG. 1, the magnetic head 1 selectively magnetizes the magnetic drum 1 uniformly magnetized in the erasing head 6 to form a magnetic latent image. The magnetic latent image is developed by the wet developer in the developing device 3 and is pressure-transferred onto the recording paper 7.

During the above-described developing operation, the developing drum 20 is brought into contact with the magnetic drum 1 and the peeling blade 22 is kept in a non-contact state. Next, with reference to FIG. 4, the developing drum 20 and the magnetic drum 1
The developing operation will be described in detail with reference to the above configuration. The magnetic drum 1 is configured by providing an elastic layer 42 made of a rubber layer around an aluminum drum 41, and further providing a magnetic layer 43 formed by coating magnetic powder with a binder around the elastic layer 42. The surface of the magnetic layer 43 may be protected by a solvent-soluble fluororesin layer as a solvent resistant coating layer in order to prevent the surface of the magnetic layer 43 from being attacked by the wet developer. The developing drum 20 has a solvent resistant elastic layer 44 made of a rubber layer around an aluminum drum 44 and is pressed against the magnetic drum. Magnetic layer 43
A magnetic latent image 45 is formed on the sheet and is conveyed to the contact portion 46. The developer 47 is supplied on the upstream side of the contact portion 46. The toner particles adhere to the changing portion of the magnetization pattern according to the leakage magnetic field 48. Since the contact portion 46 has a throttling action, the portion where the magnetic attraction force is not generated is separated from the magnetic drum 1 and stays on the upstream side of the contact portion 46. That is, when the toner particles pass through the abutting portion 46, a pressing force is applied to the magnetic drum 1.
Stripped from. Since the toner is removed by this peeling force except for the portion where the strong leakage magnetic field is generated, a toner image without background stain can be obtained.

Next, the toner image is transferred from the magnetic drum 1 to the recording paper 7 by contacting the recording paper 7 pressed by the transfer roller 4.
Is transcribed to.

Next, during non-development, the developing drum 20 is placed in the released state (indicated by 21), and the peeling blade 22 is brought into contact with the magnetic drum 1. As a result, after the developer staying on the upstream side of the contact portion 46 flows down on the downstream side, the peeling blade 22
It is peeled off and stored in the container of the developing device.

In the apparatus of the present invention, a toner image is transferred onto a recording sheet by pressure transfer using a wet type developer as a developer. In a conventional magnetic printer using a dry developer, in order to transfer the toner particles that are attracted to the magnetic drum by magnetic attraction to the recording paper, an electrostatic force greater than the magnetic attraction is applied between the recording paper and the toner particles. Alternatively, the recording paper was pressed against the magnetic drum with a large pressure to destroy the toner, and a mechanical adhesion force greater than the magnetic attraction force was applied. On the other hand, in the structure of this embodiment, since the wet type developer is used, the adhesive force between the recording paper and the toner particles can be obtained and the transfer can be performed with a small pressure. At this time, the wet toner image is likely to lose its shape when subjected to pressure in a state where a large amount of carrier liquid is contained.
On the other hand, in the configuration of this embodiment, the excess carrier liquid is squeezed when passing through the contact portion where the contact pressure between the developing drum and the magnetic drum acts during development, and the excess carrier liquid is squeezed upstream of the contact portion. To remain. Since a toner image with a small amount of carrier liquid is obtained on the magnetic drum 1, the image does not collapse during pressure transfer. Therefore, transfer can be performed with a low pressure, and a high quality transferred image can be obtained on the recording paper 7. Further, since the magnetic drum 1 has the elastic layer 42, the magnetic layer 43 is locally deformed according to the unevenness of the recording paper surface even on the recording paper having low smoothness. Therefore, a high-quality transfer image can be obtained even on rough paper. Since the carrier liquid content of the toner image after transfer is small, a fixing process such as heating after transfer is unnecessary.

Further, in the developing device of the present invention, the toner particles are selectively attached to a portion where a magnetic attraction force larger than the peeling force due to the diaphragm action, which is constituted by abutting the elastic drum, is generated. There is no chain-like adhesion of toner on the periphery of the toner image area. Therefore, there is an effect that a high quality toner image can be obtained in the form of a magnetic drum. Further, unlike a developing device using a dry developer, it is not necessary to configure a minute gap between the magnetic drum and the developing drum with high precision. For this reason, the developing device can have a simple structure.

[0024]

According to the present invention, it is possible to transfer a high quality image with a small pressure. Further, it has an effect that a high-quality transferred image can be obtained even on a recording paper having a low smoothness.

Further, since the transfer is carried out at a low pressure, there is an effect that a developing device constitution having a simple constitution can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a wet magnetic printer according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a developing device of a wet magnetic printer according to an embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a developing head used in the wet magnetic printer of the present invention.

FIG. 4 is a diagram illustrating a developing operation of the wet magnetic printer of the present invention.

FIG. 5 is a diagram showing a configuration of a conventional magnetic printer.

FIG. 6 is a diagram showing another configuration of a conventional magnetic printer.

[Explanation of symbols]

 1 magnetic drum (magnetic latent image carrier) 4 transfer roller 7 recording paper 20 developing drum 22 peeling blade 41 magnetic drum aluminum drum 42 magnetic drum elastic layer 43 magnetic drum magnetic layer 44 developing drum aluminum drum 46 contact portion 47 wet developer 49 Development drum elastic layer

Claims (2)

[Claims] 1. A wet magnetic printer which develops a magnetic latent image on a magnetic latent image carrier with a wet developer and transfers it to recording paper, wherein the magnetic latent image carrier has a magnetic layer on the surface of an elastic layer, A wet magnetic printer characterized in that after a toner image is formed on a magnetic latent image carrier, the toner image is brought into contact with and transferred to the recording paper. 2. A wet magnetic printer for developing a magnetic latent image on a magnetic latent image carrier with a wet developer and transferring it to a recording sheet, wherein the drum-shaped magnetic latent image carrier is in contact with the magnetic latent image carrier. A magnetic latent image carrier having a drum-shaped developing drum having an elastic layer on the surface thereof, the magnetic latent image carrier is brought into contact with the developing drum, and the wet developer is supplied to the contact portion. A wet magnetic printer characterized in that toner is adsorbed on the upper surface according to a magnetic latent image and is passed through a contact portion with the developing roller to remove toner in a non-image portion to perform development.