JPH0470831A - Charging member - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to an image recording device using powder.

[Prior Art] Conventionally, as a type of color copying machine, a microcapsule paper is exposed to light, the microcapsule paper is superimposed on a developer paper, and then a desired image is recorded on the developer paper by pressure development. has been put into practical use, but the color developer paper used in this color copying machine was commercially available color developer paper coated with a color developer in advance.

However, since using commercially available color developer paper is not versatile enough, the applicant has developed a powder that allows users of color copiers to easily create color developer paper using plain paper, etc. A body coating device is proposed, for example, in the specification and drawings attached to the application of Japanese Patent Application No. 2-13885.

The device first stirs a powdered color developer.

Then, the charging roller serving as the charging member and the color developer are charged by contact friction. The charged color developer is supported on a carrier such as a roller, and is opposed to a support such as plain paper in a non-contact state. This is a device that generates an electric field and applies a color developer onto the support using electrostatic force.

[Problems to be Solved by the Invention] However, the developer coating device configured as described above has the following drawbacks. That is, when a color developer is electrostatically applied to a support, the application time is extremely long. In addition, unevenness occurred on the coated surface on the support.

The inventor investigated the cause of this. As a result, it was found that the amount of charge of the color developer on the carrier roller was small and very unstable. That is, since the amount of charge was small, the color developer on the carrier roller could not fly due to electrostatic force. It was also found that the developer was either aggregated or flying. Therefore, even if some of the color developer is able to fly, the electrostatically coated surface cannot be made homogeneous. As a result, the final output image has a slow output speed and has defects, which is a serious problem.

A number of improvements were attempted to increase the amount of charge. It turned out that the material of the charging roller was the problem.

However, the charging roller needs to be made of an elastic material such as sponge or rubber. This is because it is pressed against the carrier roller, which is a rigid roller, and is charged by friction. Therefore, it was not possible to use a so-called positively charged member, and the color developer could not be sufficiently negatively charged.

The present invention has been made to solve the above-mentioned problems. That is, the purpose is to electrostatically apply a color developer onto a support consistently and at high speed. A further objective is to provide an elastic charging roller that is inexpensive and has excellent charging performance.

[Means for Solving the Problems] In order to achieve this object, the charging member of the present invention has the following features. That is, the charging member frictionally charges the powder. A feature is that an insulator with excellent charging properties is placed on the surface of the core.

Further, the powder may be a color developer. Further, the core may be an elastic cylinder. Then, a positively chargeable insulating film may be provided around it.

[Operation] According to the present invention having the above-described configuration, the charging member can impart sufficient charging properties to the powder. Moreover, it can be formed at low cost even in an elastic charging roller, which conventionally could not use a positively charging member. Therefore, an elastic charging roller for negatively charged powder can be created. As a result, it becomes possible to apply the color developer stably and quickly.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a copying machine to which the charging roller of the present invention is applied.

A document table 22 is provided on the upper surface of the apparatus outer frame 20, and an output outlet 23 is provided on the side surface.

Internally, the following process takes place. That is, after the capsule sheet 33, which is a photosensitive pressure-sensitive medium, is exposed, the color developer 44 is electrostatically applied. Thereafter, plain paper 51, which is an image receptor, and capsule sheet 33 are brought into contact with each other, and pressure development and fixing are performed.

The capsule sheet exposure conveyance unit 30 is arranged at the top of the apparatus. The capsule sheet exposure conveyance unit 30, which is a conveyance means, includes a cassette 31 and a guide roller 3.
4, an exposure lamp 36, and a lens 37. The cassette 31 includes a roll 32 of a capsule sheet 33 and a take-up roll 35. The guide roller 34 conveys the capsule sheet 33. The exposure section includes an exposure lamp 36 and a lens 37. Further, a power source E capable of applying a voltage of about 1 kilovolt to the capsule sheet 33 is connected to the winding roll 35.

The color developer application unit 40 is arranged below the exposure section. A color developer 44 , a charging roller 42 , and a carrying roller 41 are arranged inside the toner case 41 . A charging roller 42, which is a charging member, is arranged close to the carrying roller 41. The carrying roller 41, which is a carrying means,
It is made of metal materials such as steel and aluminum. The surface of the carrying roller 41 is provided with a conveying groove or a satin finish.

FIG. 2 is a detailed perspective view of a charging roller, which is a charging member. The charging roller 42 includes a shaft 45 and an elastic body 46.
and an insulator 47. The shaft 45 is made of steel, aluminum, or the like. Around the shaft 45, an elastic body 46 such as rubber or sponge is formed to a thickness of several millimeters. Furthermore, an insulator 4 is provided on the surface of the elastic body 47.
7 films are arranged. The material of the insulator 47 may be any material as long as it is a positively charged member. That is,
Nylon, acrylic, polycarbonate, melanin formalin resin, cellulose acetate, polyethylene glycol, acetal, etc. are selected.

The insulator 47 preferably has a thickness of several tens of microns.

Further, the surface of the insulator 47 is subjected to a satin finish 48 for conveying the color developer 44.

The charging roller 42 is manufactured by the following method. That is, one surface of the seamless insulating film 47 is formed with a satin finish. This satin finish is formed by blasting with abrasive grains, etching, etc. Such an insulating film 47 is placed over the shaft 45 provided with the elastic body 46. Thereafter, by heating the whole, the insulating film 47, which is a thermoplastic member, expands and comes into close contact with the shaft 45 after being cooled. As a result, an elastic roller having an insulator 47 disposed on its surface can be formed. This forming method simply involves wrapping a pre-processed insulating film, and is a very inexpensive process. By this method, a charging roller having an insulating member with excellent charging performance disposed on an elastic body can be formed at low cost.

A paper conveyance unit 50 is arranged at the bottom of the apparatus.

Plain paper 51 is stored inside the paper cassette 52. Also, the plain paper 51 kicked out by the paper feed roller 53
reaches the pressure developing unit 60 along the conveyance guide 54.

The pressure developing unit 60 includes a pair of opposing developing rollers 6.
1. Furthermore, downstream in the paper transport direction,
A fixing unit 70 is provided.

Next, the operation of the present invention will be explained.

A document (not shown) placed on document table 22 is illuminated with light from exposure lamp 36 . The reflected light forms an image on the capsule sheet 33 by the lens 37. Therefore, a latent image is formed on the capsule sheet 33. The capsule sheet 33 on which the latent image has been formed is conveyed as it is and approaches the developer coating unit 40 .

When a motor (not shown) is driven, the carrying roller 41 and the charging roller 42 rotate counterclockwise in FIG. 1.

The stored color developer 44 is rotatably conveyed while being placed on the charging roller 42 .

Further, the charging roller 42 has a surface structure made of a positively charging insulating material. The color developer 44 is given negative chargeability by frictionally charging with the positively chargeable insulating material. As a result, the color developer 44 is transferred to the charging roller 4 having an insulator.
2, stable triboelectric charging is achieved.

Therefore, the charging roller 42 always supplies sufficiently charged fine particles of the color developer 44 to the carrying roller 41 . the result,
A good supporting layer of the color developer 44 is formed on the supporting roller 41 .

Further, a positive voltage is applied to the conductive layer of the capsule sheet 33. The negatively charged color developer 44 flies in a DC electric field formed between the microcapsule sheet 33 and the carrier roller 41. The color developer 44 then adheres onto the capsule sheet 33. At this time, the carrying roller 41 carries the sufficiently charged layer of color developer 44, as described above. Therefore, electrostatic coating can be performed extremely efficiently and rapidly. On the capsule sheet 33, a uniform electrostatically coated surface with a thickness of about 40 microns is obtained.

A good and uniform color developer coating layer is stably formed on the microcapsule sheet 33. The capsule sheet 33 coated with the color developer 44 is further coated with a guide roller 34.
and reaches the pressure developing unit 50.

Further, the plain paper 51 stored in the paper cassette 52 is kicked out by the paper feed roller 53.

Plain paper 51 is fed into pressure development unit 60 along conveyance guide 54 . At this position, the plain paper 51 is brought into contact with the capsule sheet 33 coated with the color developer 44, and pressure development is performed by the developing roller 61. The developer layer is
Reacts with the dye precursor encapsulated within the microcapsules. At the same time, the color developer layer is transferred to the plain paper 51 side.

Furthermore, the plain paper 51 on which the image has been formed is thermally fixed by the fixing unit 70. Thereafter, the plain paper 51 is outputted from the outlet 23 as image recording paper.

It should be noted that the present invention is not limited to the above embodiments, and changes can be made within the scope of the invention. That is, the gist of the present invention is to provide an elastic charging roller by disposing a charging member on an elastic member. In this example, the elastic body was covered with a seamless insulating film. For example, a configuration as shown in FIG. 3 can achieve similar effects at low cost. That is, an insulating film 47 is spirally wound around the surface of the elastic member 46. It is preferable that the seam 49 between the volumes is as small as possible. With this configuration, the charging roller can be produced at a very low cost.

In addition, in this example, it was used only for the charging roller, but
Needless to say, it is also effective when applied to a carrier roller.

[Effects of the Invention] As is clear from the detailed description above, according to the present invention, the charging member can impart sufficient chargeability to powder. Moreover, it can be formed at low cost even in an elastic charging roller, which conventionally could not use a positively charging member.

Therefore, an elastic charging roller for negatively charged powder can be created. As a result, it becomes possible to apply the color developer stably and quickly.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1 to 3 show embodiments embodying the present invention. FIG. 1 is a sectional view of an image recording apparatus to which the present invention is applied, and FIG. 3 is a detailed perspective view of a charging roller of the present invention, and FIG. 3 is a detailed perspective view of a charging roller of another embodiment of the present invention. In the figure, 42 is a charging roller, 44 is a color developer, 45 is a shaft, 46 is an elastic body, 47 is an insulator, and 48 is a satin finish.

Claims (1)

[Scope of Claims] 1. A charging member for frictionally charging powder, characterized in that an insulator with excellent charging properties is disposed on the surface of a core. 2. The charging device according to claim 1, wherein the powder is a color developer, the core is an elastic cylinder, and a positively charging insulating film is provided around the core. Element.