JPH04166846A - Electrostatic thermal printing method - Google Patents

Abstract

PURPOSE:To prevent a deposition layer from being separated partially to cause inconveniency in repeated use by composing an electrostatic thermal recording layer of a polymer material with the thermal deformation temperature of 150 deg.C or more. CONSTITUTION:An electrostatic thermal recording layer 1 is composed of a polymer material with the thermal deformation temperature of 150 deg.C or more and a characteristic of leaking electric charge at 100 - 250 deg.C by performing writing from a thermal head. As such a polymer, there are polyethylene naphthalate, ethylenepropylene polyfluoride and aromatic polyamide. With this constitution, it is possible to use the material repeatedly as no thermal deformation occurs on the surface upon recording and no separation of conductive layer is generated when writing is made on the rear side.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrostatic thermal recording method, and a method for transferring an image developed on an electrostatic thermal recording medium to a receiver is a printer, facsimile, digital OHP is a method that is applied to copying and uses an electrostatic thermal recording medium as an image receptor.
It is applied to display devices such as electronic whiteboards, information boards, etc.

[Prior Art] A resin layer that reduces electrical resistance by heating, such as a resin layer made of polyvinyl chloride, polyethylene, polyester, polystyrene, styrene-maleic acid copolymer, etc., is provided on an electrically conductive substrate, and this layer is A method of forming an electrostatic latent image by electrostatically charging and irradiating with heat rays according to the original image (Japanese Patent Publication No. 85-14722), or using polyester, chlorinated polyvinyl chloride, vinyl chloride, etc. A copying method in which an electrothermographic material that is sufficiently transparent to heat rays is placed on the original image to be copied, an electrostatic charge is applied, and then an electrostatic latent image is created by the action of heat rays, which is then reversely developed and fixed using dry toner. It is known as Kosho 38-14347).

In these techniques, infrared rays are irradiated while the document is in close contact with the document, resulting in poor image resolution and the required recording energy. Another problem is that since the material is a chargeable material or directly used as a recording material for images, the royalty cost is high.

Furthermore, Tokuko Sho 35 (4722, Tokko Sho 3g-14347
All of the polyesters exemplified above have a low heat distortion temperature, and even the highest polyesters are heat distorted at 130 to 150°C.

On the other hand, since the temperature required for recording is 130 to 180[deg.] C., the disadvantage is that repeated use causes the surface to become uneven and the recording characteristics to change.

Separately, a method using polypropylene as the recording layer material proposed has a heat deformation temperature of ]20 to 130°C.
The temperature required for recording is 100 to 150°C, which is slightly lower than that of polyester, but the surface changes with repeated use.

In addition, when writing with a thermal head from the back side (Al conductive layer side), a portion of the AI vapor deposited layer peels off, which poses a problem in repeated use.

[Problems to be Solved by the Invention] The problem of the present invention is to solve the above-mentioned drawbacks, namely: (1) The surface is not thermally deformed during recording; (2) The Al conductive layer does not peel off even when writing on the back side. It is an attempt to provide a method using a recording medium.

[Means for Solving the Problems] The structure of the present invention for solving the above problems is an electrostatic thermal recording method as described in the claims.

The present invention will be specifically described with reference to the drawings.

FIG. 1 shows the structure of the electrostatic thermal recording medium used in the present invention.

The electrostatic thermal recording layer 1 is mainly composed of a polymeric substance having a heat distortion temperature of 150° C. or higher, and may contain various additives (lubricants, plasticizers, etc.). The thickness is 5 to 100 μm, preferably 1
It is 5 to 50 μm. This layer must also have the property of leaking charge at 100 to 250°C due to writing from a thermal head.

As a polymer material that has both of these properties, ■ Polyethylene naphthalate heat distortion temperature (Ts) 155°C ■ Polyfluorinated ethylene propylene heat distortion temperature (Ts) 200°C ■ Aromatic polyamide heat distortion temperature (Ts) 230° We found three types of C.

-5= Furthermore, polyimide with better heat resistance (Ts=300°C
) and Teflon (T s = 260 °C), the normal recording energy (0,5-2 n+J/dot)
(estimated recording temperature of 120 to 250°C), sufficient images could not be obtained.

The conductive layer may be a metal thin layer such as an A1 vapor deposited layer, an organic conductive phase, or the like.

As shown in Figure 2, the recording method is (A) charging (e in the figure), (B) writing with a thermal head, and (C) regular development (P/P development) with toner of opposite polarity (■ in the figure). ), and as shown in FIG. 3, there is a method of performing reversal development (N/P development) using toner of the same polarity (■ in the figure) as (A) charging (■ in the figure).

Alternatively, as shown in FIG. 4, a method may be used in which (A) after charging, (B) thermal writing is performed from the back side (Al conductive layer side), and (C) the front side (electrostatic thermal recording layer side) is developed.

In this case, it is also possible to carry out development simultaneously with thermal writing as shown in FIG.

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 A polyethylene naphthalate film with a thickness of 25 μm
1 was charged to e550V using a 500-person deposition port, and 8 do
t/mm thermal head with recording energy of 0.5 mJ/dot for Ricoh V40 (wet type P
Development was performed using liquid developer e (for PC).

Next, layer it with Ricoh PPC paper (type 6000) and
When the transfer was performed while applying a corona of 6 KV, a sharp image with an image density of 1.3 was obtained. After cleaning the remaining toner with a urethane foam rubber roller containing a developer carrier liquid (isoparaffin), this recording medium could be used again in the above recording cycle.

Even after repeating this process 500 times, images of substantially the same quality were obtained.

Example 2 AI applied to polyfluorinated ethylene propylene with a thickness of 50 μm
was charged to θ1.000 V using a 500-person deposition port, and Example 1 was thermally written with a recording energy of 1.0 mJ/dat using the same thermal head.・Magenta・
When color recording was performed using yellow and black developing units, clear full-color images were obtained.

This medium was repeatable 1000 times.

Example 3 After charging an 8 μm thick aromatic polyamide film with Al to θ500V using a 300-person evaporation port, recording energy of 1.5 mJ/dot was applied from the A1 conductive layer side using the same thermal head as in Example 1, and recording was performed at the same time. The surface of the layer was developed using the same liquid developer as in Example 1 while applying a θ bias of 500 V, and transferred to PPc paper while applying 500 V to the transfer roller, resulting in a sharp image with an image density of 1.2. I got it.

Even when this cycle was repeated 500 times, images of the same quality were obtained.

[Effects of the Invention] As explained above, since the heat deformation temperature of the electrostatic thermal recording layer used in the present invention is 150'C or higher, the recording energy of a commonly used thermal head (0.5 to 2.0 mJ
/dot; 8 dot/mm head → 2~4J /
500 to 1000 repeated recordings (equivalent to ct)
times can be used.

(2) Polyethylene naphthalate has a heat distortion temperature (Ts)
Although the temperature is slightly low at 155°C, it is possible to record at 0.5 mJ/dat (estimated recording temperature 120'C), so similar repetitions are possible.

(3) For polyfluorinated ethylene propylene, Ts = 200°
C and high < , 1.0 mJ/dat (recorded estimated temperature 1
It can be used repeatedly even at 80°C.

(4) Aromatic polyamide has a higher Ts of 230'C (L, 5 mJ/dot (estimated recorded temperature 200°C)) and can be used repeatedly.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view showing the structure of the electrostatic thermal recording medium used in the present invention, Figs. 2 to 4 are explanatory diagrams of specific examples of the method of the present invention, and Fig. 5 is an implementation of the method of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Electrostatic thermal recording layer, 2... Conductive layer, 3... Charging means, 4... Thermal head, 5... Toner, 6... Paper,

Claims (4)

[Claims] (1) After uniformly charging the electrostatic thermal recording layer, which is chargeable at room temperature and becomes non-chargeable or weakly chargeable under heating,
In an electrostatic thermal recording method in which a thermal signal corresponding to an image signal is applied to form an electrostatic latent image, and the electrostatic latent image is developed with toner of opposite polarity, this electrostatic thermal recording layer has a heat distortion temperature of 150°C or higher. An electrostatic thermal recording method characterized by comprising a polymer material of (2) The polymer material forming the electrostatic thermal recording layer is one or more polymer materials selected from polyethylene naphthalate, polyfluorinated ethylene propylene, and aromatic polyamide. Electrostatic thermal recording method. (3) The electrostatic latent image according to claim (1) is developed with a toner of opposite polarity or is reversely developed with a toner of the same polarity, and the medium having an electrostatic thermal recording layer having the visualization information is used as an image as it is. An electrostatic thermal recording method characterized in that it is used as a display. (4) Claims (1) to (3) characterized in that the thermal signal corresponding to the image signal is applied from the surface opposite to the developing surface.
The electrostatic thermal recording method according to any one of.