JPH05100444A - Electrostatic thermal recording method - Google Patents

Abstract

PURPOSE:To enable improving S/N of recording, sharp printing at a high density, initializing of the surface of the recording layer with a simple operation and improving repetitive characteristics by using a shape memory resin for an electrostatic thermal recording layer. CONSTITUTION:The electrostatic thermal recording medium contg. the shape memory resin in the recording layer 2 is used in electrostatic thermal recording. Namely, the electrostatic thermal recording layer 2 is a resin layer and the base layer 1 may be commonly used for the electrostatic thermal recording layer 2 for which a film formable material is used for its supporting member. The electrostatic thermal recording material is constituted of the shape memory resins, such as polynolbornane having 30 to 100 deg.C glass transition temp., trans-1, 4-polyisoprene, styrene-butadiene copolymer, polyurethane, and polyester polymer alloy, etc. The S/N of the recording in the electrostatic thermal recording is improved in this way and the bright printing of the high density is obtd. In addition, the repetitive recording characteristics are improved as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses a dielectric as a latent image body,
The present invention relates to a transfer type electrostatic thermal recording method (electrothermography) for forming a latent image by heating and a recording medium used therefor. In addition, a printer using this recording method,
It concerns fax machines and digital copiers.

[0002]

2. Description of the Related Art A method of visualizing an electrically conductive substrate by providing a resin layer whose electric resistance decreases with temperature by heating, electrostatically charging the layer, and applying heat by infrared irradiation is known. 35-14722, 37-1587
8, known in Japanese Examined Patent Publication No. 38-14347. It is described that these use a substance having a property that the electric resistance of the resin layer (macromolecular compound) decreases or increases with temperature. JP-A-51-68233, JP-A-52-
19534 discloses a technique of using a thermal signal to be applied instead of a thermal head. However, it lacks the disclosure of specific technical means and requires a lot of related technical development in order to be put to practical use. In fact, an image forming apparatus that forms an electrostatic latent image by heating is still commercialized. Not not.

On the other hand, there are many products of the image forming apparatus adopting the electrophotographic method. However, the electrophotographic method has a problem due to the photosensitive member. One is that the cost is increased due to the manufacturing of the photoconductor, and the cost is increased because the light-shielding property of the photoconductor is required as the device configuration. In addition, there is a problem in that the optical unit has a lot of space and the irradiation direction is restricted, which impairs the degree of freedom in the mechanical configuration. In addition, Japanese Patent Application No. 2 applied for by the applicant
No. 213756 uses a thermal head for heating,
A description of applying a bias voltage to a precharged thermal head, or a thermal head, and a recording layer having lubricity, polypropylene, polypropylene-based copolymer, fluorinated acrylic-acrylic copolymer, perfluoroalkyl It is described that the recording medium is an acrylate, a silicone polymer, or a mixture thereof.
Moreover, in Japanese Patent Application No. 2-28806, the glass transition temperature of the material is equal to or higher than the operating environment temperature, and the heat deformation temperature is higher than the glass transition temperature due to the characteristics of the above-mentioned resin layer dielectric. It is described that the deformation temperature is higher than the thermal writing temperature.

[0004]

However, in electrostatic thermal recording, it is an important technique to improve the S / N of recording by rapidly eliminating the charge on the recording layer at a predetermined temperature. The materials proposed have not been sufficient. Further, the recording medium proposed in Japanese Patent Application No. 2-213756, etc., allows sharp and high-density printing to be repeatedly recorded if conditions are selected, but in order to improve the performance of repeated recording, the thermal history after recording is improved. It is important to return the deformation due to the condition to the initial state, and the usable temperature range was narrow in the materials proposed previously. The present invention is based on these circumstances.
To provide an electrostatic heat recording method capable of improving recording S / N in electrostatic heat recording, obtaining clear and high density printing, and excellent in repeated recording characteristics, and an electrostatic heat recording material therefor. It is intended.

[0005]

[Means for Solving the Problems] As described above,
In electrostatic thermal recording, it is an important technology to improve the S / N of recording by being able to rapidly eliminate the charge on the recording layer at a predetermined temperature. However, the materials proposed as being usable conventionally are not yet sufficient. There wasn't. Further, if the repetition is continued, there is a concern that the deformation due to the thermal history during recording remains and the recording characteristics change. Therefore, in the present invention, a shape memory resin in which the aggregated state of molecules rapidly changes at the glass transition temperature was examined as a material for electrostatic thermal recording, and sufficient characteristics were obtained. That is, the present invention comprises an electrostatic thermal recording method characterized by using an electrostatic thermal recording medium containing a shape memory resin in a recording layer in electrostatic thermal recording, and a shape memory resin having a glass transition temperature of 30 to 100 ° C. The present invention relates to an electrostatic heat recording material. The structure of the recording medium used in the electrostatic thermal recording method of the present invention will be described with reference to the drawings. FIG. 1 shows an example of the recording medium, and FIG. 2 shows another example. 1 and 2, 1 is a base layer, 2 is an electrostatic thermal recording layer, and 3 is a conductive layer. The electrostatic heat recording layer 2 is a resin layer, and the base layer 1 may also be used as an electrostatic heat recording layer in which a film-forming material is used as a supporting member thereof.

[0006] The conductive layer 3 serves to make the charge uniform, but since it fulfills this function, it is not always necessary when it is achieved by sandwiching it in a conductive member such as a counter roller or a counter plate. As the material of the conductive layer, an Al vapor deposition layer or various conductive treatment agents are used. Further, it can be composed of a metal drum or a belt. Next, the basic structure of the transfer type electrostatic recording method of the present invention will be described with reference to FIG. Charging process (Fig. 3a) The method using corona discharge provides the most uniform charging, but the method of applying voltage to a metal roller and various methods such as friction charging with a brush having an organic or inorganic material surface or a roller having a sponge material are also available. Can be used. Heating process by thermal signal (Fig. 3b) In the conventional thermal electrostatic recording, the original and the recording medium were superposed, and the absorption-heat generation of the black part by infrared irradiation was used (analog signal). Heating is performed by the digital signal of. As the thermal head, a serial head or a line head having a high resolution of 8 dot / mm to 16 dot / mm is used.

Development Step (FIG. 3c) This is the same as the powder toner development or liquid toner development that is carried out in normal electrophotography, but is reversal development. [Toner that has the same sign as the remaining charge (negative charge in the figure) that does not receive the heat signal

[Equation 1] Development by Repulsive Electric Field] Transfer Step (FIG. 3D) This step is performed in the same manner as in electrophotography. In the case of powder toner, it is heated and fixed by a heat roller after transfer. In the case of liquid toner, it is only necessary to dry the remaining liquid. Cleaning step (Fig. 3e) After transfer, to ensure a good surface for the next image,
The powder or liquid toner left on the electrostatic recording layer must be removed before reuse. Next, the surface is initialized by heating at a temperature higher than the glass transition temperature (Tg) of the shape memory resin as the recording layer while applying pressure with a heat roller or the like. By repeating these steps,
Digital information can be recorded on plain paper.

The shape memory resin used in the recording layer of the electrostatic thermal recording medium of the present invention has a glass transition temperature (Tg) of 30 ° C. to 1 ° C.
The temperature is preferably 00 ° C., and if it is lower than 30 ° C., sufficient charging cannot be obtained, and if it exceeds 100 ° C., the sensitivity becomes insufficient. Specific examples of the shape memory resin include polynorbornene (Tg35 ° C. manufactured by Nippon Zeon) trans 1.4 polyisoprene (Tg67 ° C. manufactured by Kuraray) styrene-butadiene copolymer (Tg70 ° C. manufactured by Asahi Kasei) Polyurethane (Tg30 manufactured by Mitsubishi Heavy Industries)
C.) Polyester polymer alloy (Zeon Sable Tg 40 ° C. to 80 ° C. manufactured by Nippon Zeon) or the like can be used. These shape memory resins can be formed into a desired shape by heating at 120 ° C. to 200 ° C. For example, if they are heated while being pressed by a heating roller, there is fine unevenness caused by thermal deformation during recording. Even if it is repeatedly recorded, it is possible to print with constant sharpness and high density. The recording medium containing the above-mentioned electrostatic thermal recording material of the present invention can be repeatedly used by heating it while applying pressure at a temperature higher than the glass transition temperature after recording.

[0009]

EXAMPLES The present invention will be further described below with reference to examples. Example 1 An electrostatic thermal recording medium having polynorbornene of 50 μm on an Al substrate was charged at −700 V, thermal writing was performed with a thermal head of 8 dots / mm, development was performed with a toner of negative polarity, and the image was transferred to paper. However, sharp and high-density printing was performed. When this recording medium was heated to 150 ° C. while being pressed by a heating roller, the surface was initialized and repeated recording was possible. Example 2 An electrostatic thermal recording medium having a 25 μm styrene-butadiene copolymer (Asmer made by Asahi Kasei) on an Al substrate was charged at −500 V, and thermal writing, development and transfer were performed in the same manner as in Example 1. However, similarly, sharp and high-density printing was performed. This recording medium was similarly heated to 120 ° C.
Repeated recording was possible when heated to.

[0010]

As described above, according to the electrostatic heat recording method of the present invention, the S / N of recording is improved by using the shape memory resin in the electrostatic heat recording layer, and the sharp and high density printing can be performed. In addition, the surface of the recording layer can be initialized by a simple operation, and it has excellent repeatability.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a recording medium used in an electrostatic thermal recording method of the present invention.

FIG. 2 is an explanatory view of another example of a recording medium used in the electrostatic thermal recording method of the present invention.

FIG. 3 is a process explanatory view of the electrostatic thermal recording method of the present invention, in which a
Is a charging step, b is a heating step by a heat signal, c is a developing step, d is a transfer step, and e is a cleaning step.

[Explanation of symbols]

 1 base layer, 2 electrostatic thermal recording layer, 3 conductive layer, 4 corona charging device, 5 thermal head, 6 toner, 7 paper

Claims (3)

[Claims] 1. An electrostatic thermal recording method, wherein in electrostatic thermal recording, an electrostatic thermal recording medium containing a shape memory resin in a recording layer is used. 2. An electrostatic thermal recording material comprising a shape memory resin having a glass transition temperature of 30 to 100 ° C. 3. The electrostatic thermal recording material according to claim 2, wherein the shape memory resin contains any one of polynorbornene, trans-1,4-polyisoprene, styrene-butadiene copolymer, polyurethane and polyester polymer alloy.