JPH07102737B2 - Energization transfer recording method and energization head - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current-carrying transfer recording method and a current-carrying head used in the field of image formation for providing high-quality images with high speed and high sensitivity.

2. Description of the Related Art In a current transfer recording technique that uses a melted ink as a color material, which is generally known, a film containing carbon in a polycarbonate resin is used as a resistance sheet. The thermal diffusion coefficient of this resistance sheet is about 10 ⁵ m ² / s. Also, in order to reduce the contact resistance between the energizing head and the resistance sheet,
A conductive thin film is formed as a second resistance layer on the surface of the resistance sheet (first resistance layer) by a PVD (Pee-Vee) method. Literature (K.K.C, T.C.Chu,
Proceedings of the SId, 28/1, pp.87-91 (1987)) shows that when a Cr-N thin film with a specific resistance of 0.03 ohm · cm or less is formed at 1000 A ° or less as a second resistance layer, It is said that it can be expected to reduce resistance. The thermal diffusion coefficient of the multilayer resistance sheet thus formed is at most 10 ⁶ m ² / s. In addition, ceramics such as alumina, glaze, and thermosetting resin are used for the insulating support that holds the electrode array (multi-stylus) of the commonly used energizing head.

However, when gradation recording is performed by using a sublimable dye as a color material in order to obtain a full-color high-quality image, the recording energy is high, and therefore the conventional energization transfer recording method is as follows. Have some challenges.

(1) When a resistance sheet containing carbon in polycarbonate is contacted with an energizing head for recording, the heat resistance and the thermal sliding property are poor, and the head surface becomes dirty and the image quality is deteriorated. The contact resistance is also reduced when the second inorganic thin film resistance layer is provided by the PVD method, but the thermal sliding characteristics are particularly poor, and the reduction of the friction coefficient between the resistance sheet and the head has not been achieved. It causes dirt. This tendency is large in the relative speed type multi-time recording (a recording method in which the transfer member traveling speed is slowed with respect to the recording paper), and the thermomechanical and electrical characteristics of the resistance sheet are significantly deteriorated.

(2) When a stylus electrode and a common electrode are opposed to each other as a current-carrying head and the signal current is recorded in parallel with the heating substrate, the current density distribution is concentrated in the vicinity of the stylus to obtain a large and uniform recording dot. It is not suitable for gradation recording because it does not exist.

(3) The thermal diffusion coefficient of the insulating support of the head and the resistance sheet has not been optimized, and high speed and high sensitivity have not been made in consideration of heat storage control.

The present invention aims to solve such problems of the conventional technology.

Means for Solving the Problems The present invention is an electric transfer recording method in which an electric head is brought into contact with a resistance sheet for recording, and the thermal diffusion coefficient of the resistance sheet is (1-100) × 10 ⁶ m ² / s. In the range of (0.1-50) × 10 ⁶ m ² / s, the thermal diffusion coefficient of the insulating support of the energizing head is a combination of the energizing transfer recording method, and the resistance sheet on one surface of the energizing head is used. This is a current transfer recording method characterized in that the friction coefficient between and is 0.2 or less.

When the thermal diffusion coefficient of the insulating support of the energizing head is large, the high speed response is good but the thermal efficiency is poor. If the thermal diffusion coefficient is small, the thermal efficiency will be good, but high-speed recording will not be possible because of heat storage. However, even with such a current-carrying head having a small thermal diffusion coefficient, if the thermal diffusion coefficient of the resistance sheet in contact with the head is increased, the heat storage of the head and the resistance sheet is suppressed, and high-speed, high-sensitivity recording with good thermal efficiency becomes possible. Further, the heat pulse from the head is not concentrated in the vicinity of the stylus electrode and is homogenized between the opposing electrodes, which enables smooth gradation recording.

Further, by reducing the friction coefficient between the head and the resistance sheet at high temperature, the head stain due to the melting of the resin of the resistance sheet is reduced, and uniform recording dots can be obtained.

EXAMPLE FIG. 1 shows a sectional view of the structure of an example of the present invention, and FIG. 2 shows a comparison between a conventional example and a characteristic example according to the present invention.

In the figure, 1 is a resistance sheet, 2 is a current-carrying head, 3 is a color material layer, 4 is a transfer member, 5 is image receiving paper, and 6 is a platen.

The resistance sheet 1 comprises a first resistance layer 11 and a second resistance layer 12. As the first resistance layer 11, a resistance film formed by mixing conductive particles 17 such as carbon into a heat resistant resin is used. This heat resistant resin includes polyimide, aramid, polycarbonate, polyester, polyphenyl sulfide,
A resin capable of forming a film such as polyetherketone is used. These resistive films have a thickness of about 4-10u and surface resistance of about 1K.
The film is formed on the ohmic layer, but since it contains 10-30% of carbon and the like, its surface becomes rough and the inside of the film becomes porous, resulting in deterioration of thermomechanical strength.

The second resistance layer 12 compensates for the inconvenience of the first resistance layer and requires heat resistance, lubricity, proper resistance and surface property, and at least the conductive inorganic particles 14, the non-conductive inorganic particles 15 and the heat resistance. It is composed of resin 16. This may include an organic lubricant. The thickness is about 0.2-6 u, and its surface is finely roughened by inorganic particles and has a surface resistance an order of magnitude higher than that of the first resistance layer. A smaller surface resistance is used when the second resistance layer is the main heating layer. The heat-resistant resin 16 is a thermosetting resin, an ultraviolet curable resin, or the like. More specifically, epoxy, melamine, urethane, various acrylates, silicones (organoalkoxysilane hard coat materials) or silanes with acrylates, titanate coupling reaction products, and graft reaction products are used. The conductive inorganic particles 14 are generally carbon black (Ketjen Black), and metal particles having a particle size of submicron or less, and graphite are also used. As the non-conductive inorganic particles 15, abrasives such as silica, alumina, titanium oxide, and silicon carbide having a particle size of submicron or less, and solid lubricants such as molybdenum disulfide and talc are used. As the organic lubricant, reactive type or non-reactive type silicone oil, and silicone type or fluff type surfactant are used.
The second resistance layer composition described above has a weight ratio of 14,15,16 of about
The paint is prepared so that the ratio is 1: 1: 1. However, the weight ratio is not limited to this.

The color material layer 3 is formed of at least a sublimable dye and a binder resin. The transfer body 4 includes the resistance sheet 1 and the color material layer 3.

The current-carrying head 2 is composed of a stylus 21, a common electrode 22, and a support 23 to form a line head. The electrodes 21 and 22 are made of copper, tungsten, titanium, brass, etc., and the ceramic 23 is more wear-resistant than the electrodes and has a large wall-opening property (boron nitride, mica ceramics, etc.). The resolution of the electrode is 6-16 dots / mm.

A signal current path applied between the electrodes 22 and 22 flows vertically through the second resistance layer and parallel through the first resistance layer with the film. The recording condition at this time is that the pulse width applied to one dot is 1 ms, the recording cycle for one line is 4 ms, and the peak temperature of the heat generating portion reaches 300-400 ° C. The current density distribution, that is, the peak temperature distribution is particularly large just below the stylus electrode. Under such high temperature and high pressure (3K
(g / 100 cm), the transfer member 4 and the image receiving member 5 run between the platen and the head. At this time, the electrical contact with the electrodes is made by the slightly roughened conductive inorganic particles 14, and the non-conductive inorganic particles 15 instantly generate the second resistance layer on the head.
Cleans the stains caused by the composition of 12 and imparts the slip property between the head and the resistance interlayer. The organic lubricant contained in the first and second resistance layers springs out to the interface at high temperature to provide lubricity. At this time, since the resistance layer 12 has a large proportion of inorganic particles, the heat resistance is also improved. If dirt is deposited on the head, high-quality gradation recording cannot be obtained. It was experimentally found that the friction coefficient at this time must be 0.2 or less at room temperature to enable smooth running recording between the head and the sheet.
Further, in order to promote this, the head may be configured so that the lubricant is spouted from the surface of the head at a high temperature.

On the other hand, the thermal diffusion coefficient A (A = k / dc,
k: thermal conductivity, d: density, c: specific heat) has a value of 1-100 in the unit of 10 ⁶ m ² / s. The value A of the first resistance layer is 0.2 or less. A value of aramid film without carbon is 0.
In 05, aluminum, copper, tungsten, silicon, silicon carbide, etc. have values of 20-150. In this way, the second resistance layer has an A value close to that of a metal, so that the high peak temperature just below the stylus diffuses and decreases. Therefore, the recording dots become large and uniform, and the thermal load on the first and second resistance layer compositions is reduced.

If the thermal diffusion coefficient of the insulating support of the current-carrying head is large irrespective of the thermal diffusion coefficient of the resistance sheet, the high speed response is good but the thermal efficiency is poor and a large recording energy is required. When a conventional resistance sheet having a small thermal diffusion coefficient is used, the head of an insulating support having a small thermal diffusion coefficient has good thermal efficiency, but fog of a recorded image occurs due to heat storage, which is not suitable for high speed recording. However, at this time, if a resistance sheet having a large thermal diffusion coefficient as described above is used, the heat accumulated on the head is absorbed and high-speed, high-sensitivity recording becomes possible. This is shown in FIG. The figure is a graph on a logarithmic scale. The insulating support with a relatively large thermal diffusion coefficient is boron nitride (A = 15), alumina (A = 6), etc., and the relatively small insulating support is glaze (A = 0.5), mica ceramics (A = 1), etc. is there. The combination of the resistance sheet and the thermal diffusion coefficient of the insulating support shown below is preferable.

A: (1-100) of resistance sheet A: (0.1-50) of insulating support of energizing head Further specific examples will be described.

(1) Energizing head: A6 line head, resolution 6 dots /
mm (stylus electrode material is tungsten), mica ceramics insulating support, applied pulse width 1ms, recording cycle 4ms /
Record constant velocity and relative velocity at line and pressure of 3Kg / 100mm. (Velocity ratio n = 1-10) (2) First resistance layer: A film formed by mixing carbon in aramid resin to a thickness of 6u and a surface resistance of 1K ohm.

(3) Second resistance layer: Ketjen black 1 having a primary particle size of 10 mu, silicon dioxide 1 having a primary particle size of 10 mu produced by vapor phase growth method 1, epoxy resin 0.8, isocyanate 0.2, and dimethyl silicone oil 0.05 weight solid content A film having a thickness of 4u formed on the first resistance layer so as to have a ratio.

(4) Coloring material layer: formed with a thickness of 1 u in terms of the weight solid content ratio of indoaniline-based cyan sublimable dye 1 and polycarbonate resin 1.

(5) Receptor: A 100 u milk white PET film formed to a thickness of 8 u based on the weight solid content ratio of polyester resin 1 and silica 0.2.

As a result of conducting the recording experiment under the above conditions, as shown by the black mark in FIG. ² , there is no fog on the image with the recording energy of 4 ms / line and the recording energy of ² J / cm ² , and the smooth gradation recording characteristic shows the relative speed. It was obtained by law. This recorded image has an image quality equivalent to that of dye transfer recording using a thermal head as a recording unit. In addition to the above dyes, magenta and yellow colors were used to obtain an A6 full-color image in about 10 seconds.

EFFECTS OF THE INVENTION As described above, according to the present invention, (1) 1-line recording speed of 4 ms, high speed of recording energy of ² J / cm ² , and high sensitivity full-color recording are possible. Also, (2) relative speed ratio n =
10 was obtained under the above recording conditions. Further, (3) it is possible to provide a stable resistance sheet without head contamination. Furthermore, (4) large and uniform recording dots can be formed.

[Brief description of drawings]

FIG. 1 is a sectional view of the structure of one embodiment of the present invention, and FIG. 2 is a graph showing a comparison of characteristic examples of the present invention and a conventional structure. 1 ... Resistance sheet, 2 ... Conductive head, 23 ... Insulating support.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location B41M 5/26 5/38 B41J 3/20 117 F (72) Inventor Hiromu Matsuda Kadoma City, Osaka Prefecture Daiji Kadoma 1006 Matsushita Electric Industrial Co., Ltd. (72) Inventor Tetsuji Kawakami Osaka Kadoma City Kadoma 1006 Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A current-carrying transfer recording method for recording by contacting a current-carrying head with a resistance sheet, wherein the current-carrying head has a thermal diffusion coefficient of (1-100) × 10 ⁶ m ² / s. The thermal diffusion coefficient of the insulating support of (0.1−50) × 10 ⁶ m ² / s
An electric current transfer recording method characterized in that the combination is performed in the range of. 2. A current-transfer recording method according to claim 1, wherein the friction coefficient of the single surface of the current-carrying head with the resistance sheet is 0.2 or less. 3. The thermal diffusion coefficient of the insulating support of the head is (0.
The range of 1-50) × 10 ⁶ m ² / s is used, and the coefficient of friction of the single surface of the current-carrying head with the resistance sheet is 0.2 or less. Energizing head.