JPH03210574A - Electrostatic thermal recording method - 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 field] The present invention relates to an electrostatic thermal recording method and apparatus.

Specifically, an electrostatic charge image is formed on a specific recording medium, which is then reversely developed and fixed as is. Alternatively, a toner image that has been reversely developed is transferred and fixed onto a recording paper such as plain paper, and then the toner image is transferred to the specific recording medium again. The present invention relates to an electrostatic thermal recording method and apparatus for recording.

[Conventional technology]

Various recording methods have been proposed, including (1) providing a resin layer that reduces electrical resistance by heating on an electrically conductive substrate, and electrostatically charging this layer;
A method of forming an electrostatic latent image of an image by irradiating heat rays according to the original image (Japanese Patent Publication No. 35-14722), or (2) placing an electrothermographic material that sufficiently transmits heat rays on the original image to be copied. , after giving an electrostatic charge,
A copying method in which an electrostatic latent image is created by the action of heat rays, reversal development is performed using dry toner, and then the image is fixed by scanning (Special Publication Publication No. 38-14
347 Publication), etc. are known. However, these methods still have unresolved problems, such as poor image resolution and high recording energy requirements because infrared rays are irradiated while the document is in close contact with the document.

[Problem to be solved by the invention]

The present invention solves the above-mentioned unresolved problems, and provides a method and apparatus that are simpler in process than conventional techniques and that allow digital information to be recorded on plain paper if necessary. .

[Means to solve the problem]

The first aspect of the present invention is to uniformly charge a recording medium having an electrostatic thermal recording layer that is chargeable at room temperature and becomes non-conductive or weakly chargeable under heating, and then generates a thermal signal corresponding to an image signal. This electrostatic thermal recording method is characterized in that an electrostatic latent image is formed by applying a toner to form an electrostatic latent image, and the electrostatic latent image is reversely developed with a toner having the same polarity as the uniformly charged polarity to form an image on the recording layer. .

The second aspect of the present invention is to use a rolled sheet as a recording medium having an electrostatic thermal recording layer that is chargeable at room temperature and becomes non-chargeable or weakly chargeable under heating, and is transferred from the sheet supply side by a sheet feeding means. After the recording medium is conveyed and used for one cycle of charging, thermal writing, reversal development, and transfer to recording paper, the used recording medium is again wound to the sheet winding side by a sheet winding means. This is a transfer type electrostatic thermal recording method characterized by the following.

The third aspect of the present invention is to use a roll-shaped recording medium having an electrostatic thermal recording layer that is chargeable at room temperature and becomes non-chargeable or weakly chargeable under heating, and the recording medium sheet is fed from the sheet supply side. After being used for one cycle of charging, thermal writing, reversal development, and transfer to recording paper while being conveyed,
The used recording medium sheet is wound up again to the sheet winding side, and is characterized in that at least a thermal writing means, a developing means, and a transfer means are arranged on one platen drum. This is a transfer type electrostatic thermal recording device. This transfer type electrostatic thermal recording device is particularly useful for carrying out the second method of the present invention.

The present inventors have so far carried out research and examination on various recording media (recording media) that are chargeable at room temperature and become non-chargeable or weakly chargeable under heating. According to the use of electrostatic thermal recording media).

It was confirmed that high-quality images could be obtained without any troublesome operations. The present invention has been achieved thereby.

In the following, the invention will be explained in more detail with reference to the additional drawings.

First, the electrostatic thermal recording medium used in the present invention has an electrostatic thermal recording layer 15 on the surface of the base layer 14, as shown in FIG.
is formed, and a conductive layer 16 is formed on the back surface of the base layer 14. However, if the back surface of the base layer 14 is in contact with a conductive drum or the like, the conductive layer 16 may not be intentionally formed. As shown in FIG.
The conductive layer 16 may not be provided.

Similarly, if the platen drum 13 is electrically conductive and grounded, as in the device shown in FIG. 4 (corresponding to the third embodiment of the present invention), electrostatic thermal recording The medium 1 does not need to be intentionally provided with the conductive layer 16.

The base layer 14 is a support for the electrostatic thermal recording layer 15, and is made of a film (approximately 1-30 mm thick) made of polyester, polyvinyl chloride, polyethylene, polypropylene, etc., which has a voltage resistance other than 101 Ωc at room temperature. If the base layer 14 meets the requirements for the electrostatic thermal recording layer 15, the base layer 14 can also serve as the electrostatic thermal recording layer.

The electrostatic thermal recording layer 15 is a thermoplastic layer (with a thickness of about 1 to 3
0I@), and the electrical resistance is 101@ΩC at room temperature.
■It is more than 109Ωcm when the heating signal is received.
The following materials are suitable. Specifically, polyvinyl chloride, cellulose acetate, polyacetal, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, acrylic polymer, styrenic polymer, polyester, polyamide, polyethylene, polypropylene, fluorinated acrylic Examples include acrylic copolymers and styrene-acrylic copolymers.

The material for the conductive layer 16 is a vapor deposited layer (100 to 200
The thermal head side platen drum 13' shown in FIG. 3 or the platen drum 13 shown in FIG.
If a material with a thickness of 0.09 Ωam or less, preferably 10"0 cm or less) is used, it can also serve as a base layer.

The manner in which recording is performed using such an electrostatic thermal recording medium 1 will be explained below with reference to FIG.

First, (a) uniform corona charging is applied to the thermoelectrostatic recording layer 14 of the electrostatic recording medium, and (b) a signal corresponding to an image signal is applied to the thermal head 11. By this heating, the resistance value of the heated electrostatic thermal recording layer 14 decreases and the charge disappears.Next, (C) reverse development is performed with a toner having the same polarity as that during uniform corona charging, and the electrostatic thermal recording medium 1 Both images are formed above. It does not matter whether a one-component dry developer, a two-component dry developer, or a liquid developer is used for development.
This will be fixed if necessary. Alternatively, (d) it can also be transferred onto recording paper 7 such as plain paper.

As for the charging operation, as described above, the method using corona discharge is the most uniform means, but a roller charging device using a metal roller or a charging device using a conductive brush may also be used. When charging with a metal roller, one of the rollers should be made of a conductive elastic material, such as synthetic rubber such as silicone, fluorine, or urethane, in order to provide uniform charging to obtain good contact. It is desirable to use a charging device having an elastic roller in which low resistance particles such as carbon are dispersed.

It is also possible to use the electrostatic thermal recording medium repeatedly. In this case, the electrostatic thermal recording medium after the transfer process is wound onto a take-up reel, but is rewound again and used for new recording. However, in repeated use, it is necessary to clean and remove static electricity for each cycle of the electrostatic thermal recording medium.

〔Example〕

Examples will be shown next, but the present invention is not limited thereto.

Example 1 A copying machine as shown in FIG. 3 was prepared. here,
A platen roller with carbon black dispersed on the platen drum 13' on the thermal head side (rubber hardness JISA
40 degrees 1 volume resistivity 1.5 x 10"0 cm) was used. After charging an electrostatic thermal recording medium of a polypropylene sheet with a thickness of about 15 m to a surface potential of -600 V using a roller, 8 dots/m Rad to the thermal of 0.
Applying a character signal with a recording energy of 5 mJ/dot,
Reversal development was carried out using a commercially available developer (liquid developer for wet-type copying machines manufactured by Cuco Co., Ltd.), and a reverse bias was applied at the transfer section to obtain a transferred image on plain paper. The used recording medium was wound onto a take-up reel 6. The printed portion of the electrostatic thermal recording medium sheet after the recording was slightly damaged due to the heating and pressure applied to the writing portion, but this does not affect subsequent printing since it was wound up.

Example 2 Transfer recording was performed under similar conditions using the apparatus shown in FIG. 4 instead of the apparatus shown in FIG.

Results similar to those in Example 1 were obtained.

〔Effect of the invention〕

According to the present invention, (1) toner cleaning, static electricity removal, etc. can be omitted if the electrostatic thermal recording medium is used for only one recording, and (2) since it is disposable, there is no deterioration such as wrinkles, and it is reliable. High quality images can be easily obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an example of an electrostatic thermal recording medium according to the present invention. FIG. 2 is an explanatory diagram of an image obtained by the method of the present invention. 3 and 4 are schematic illustrations of an example of apparatus useful in carrying out the method of the present invention. 1... Electrostatic thermal recording medium (14... Base layer, 15... Electrostatic thermal recording layer, 16
... Conductive layer) 2... Roller for feeding and loading (2'... Corotron for charging) 3... Development roller 4... Take-up reroller 5... Delivery reel 6... Winding Reel 7... Recording paper 8... Platen drum (thermal head side) 8'...
・Platen drum (transfer side) 9... Transfer roller (9'... Transfer corotron) 10... Clamp 11... Thermal head 12... Head driver 13... Platen drum

Claims (3)

[Claims] (1) After uniformly charging a recording medium with an electrostatic thermal recording layer that is chargeable at room temperature and becomes non-chargeable or weakly chargeable under heating, a thermal signal corresponding to the image signal is applied to the recording medium to generate an electrostatic charge. 1. An electrostatic thermal recording method comprising forming a latent image and developing the electrostatic latent image in reverse with toner having the same polarity as the uniformly charged polarity to form an image on the recording medium. (2) A recording medium having an electrostatic thermal recording layer that is chargeable at room temperature and becomes non-chargeable or weakly chargeable under heating is used as a rolled sheet, and the recording medium is conveyed from the sheet supply side by a sheet feeding means. After being used for one cycle of charging, thermal writing, reversal development, and transfer to recording paper,
A transfer electrostatic thermal recording method characterized in that the used recording medium is again wound up on the sheet winding side by a sheet winding means. (3) A recording medium having an electrostatic thermal recording layer that is chargeable at room temperature and becomes non-chargeable or weakly chargeable under heating is formed into a roll-shaped sheet, and the recording medium sheet is conveyed from the sheet supply side. After the used recording medium sheet is used for one cycle of charging, thermal writing, reversal development, and transfer to recording paper, the used recording medium sheet is wound up again to the sheet winding side, and at least thermal writing is performed. 1. A transfer type electrostatic thermal recording device, characterized in that a developing device, a developing device, and a transferring device are arranged on one platen drum.