JPH02293159A - Electric conduction head - Google Patents

Abstract

PURPOSE:To perform a high-speed, high-sensitivity full color recording by a method wherein in an electric conduction head formed by embedding a pair of electrodes opposed to each other in an insulating substrate a thermal diffusivity of the insulating substrate inside of the electrode pair is determined to be less than that of the insulating substrate outside the electrode pair. CONSTITUTION:With the application of a signal current to an electrode pair 23a, 23b, a large thermal diffusivity of an insulating substrate 21 outside the electrode pair 23a, 23b causes heat pulses converging on and around the electrode pair 23a, 23b in a resistant sheet 11 to diffuse along the outer insulating substrate 21. As a result, a recording head to be produced has a uniform rectangular form suitably for obtaining a high color density. Simultaneously, an excessive heat accumulated in the resistant sheet 11 is accordingly released. Thus, a turbidity of color and a reduction of resolving power can be avoided even in a high-speed recording. At this time, the reduction of sensitivity can be inhibited by a heat insulating effect resulting from a small thermal diffusivity of an insulating substrate 22 inside the electrode pair 23a, 23b.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an energizing head used in the image forming field that provides high-speed, high-sensitivity, and high-quality images.

BACKGROUND ART In order to realize full-color images at high speed, an electric dye transfer technique using an ink sheet in which ink containing a sublimable dye is provided on a resistive sheet and an electric foot is suitable.

The insulating support that holds the electrode array (multi-stylus) of the current-carrying head is generally made of alumina, quartz, thermosetting resin, etc.
The same material is used regardless of whether the electrode pair is inside or outside.

Problems to be Solved by the Invention When performing gradation recording at high speed using sublimable dye as a coloring material in order to obtain full-color, high-quality images, the recording I energy is high, so conventional current-carrying heads have the following problems. There are many challenges.

The thermal diffusion coefficient of the insulating support of the head has not been optimized, and the high speed, high sensitivity, and recording shaft have not been optimized. If an insulating support with a small thermal diffusion coefficient is used, the sensitivity will be improved, but the recorded image will be clouded in color and the resolution will be reduced due to heat accumulation. On the other hand, if an insulating support with a large thermal diffusion coefficient is used, the sensitivity will decrease and the characteristics of electrical transfer will be lost. Further, the thermal rush generated as a result of applying a signal current to the electrode pair is concentrated near the electrodes of the resistive sheet, making it impossible to obtain a homogeneous recording pad.

The present invention aims to solve the problems of the prior art.

Means for Solving the Problems In an energized head in which a pair of opposing electrodes is embedded in an insulating support, the thermal diffusion coefficient of the insulating support inside the electrode pair is made smaller than that of the outside.

When a signal current is applied to the working electrode pair, the thermal diffusion coefficient of the insulating support outside the electrode pair is large, so the concentrated thermal flux in the resistor sheet near the electrode pair is diffused along the insulating support outside the electrode pair. . As a result, the formed recording medium has a uniform rectangular shape and has a high color density. At the same time, excess heat accumulated in the resistor can be properly dissipated, which prevents color turbidity and resolution degradation even during high-speed recording. At this time,
A decrease in sensitivity can be suppressed due to the heat retention effect due to the small thermal diffusion coefficient of the insulating support inside the electrode pair.

Example FIG. 1 shows a sectional view of the structure of an embodiment of the present invention.

1 is an ink sheet, 2 is a current-carrying head, 3 is an image receiving paper, and 4 is a filen.

The ink liquid 1 has a coloring material layer 12 formed on the resistance liquid 1.11. As the resistive film 11, a resistive film formed by mixing conductive particles such as carne into a heat-resistant resin is used. This heat-resistant resin has wood imprint,
Resins capable of forming a film such as aramid, nery carnenate, nylyester, nylyphenyl sulfide, and nylyetherketone are used. These resistive films are about 4~ thick! The film is formed to have a surface resistance of about 5 μm and a surface resistance of about IK ohm.

The coloring material layer I2 is formed of at least a sublimable dye and a binder resin.

The image receiving paper 3 has a dye layer 3l provided on a base paper 32.

The current-carrying shaft 2 has seven electrode pairs {23a, 23b embedded in the insulating supports 2, 22, and is constructed as a river shaft.

The electrodes are made of copper, phosphor bronze, tank steel, titanium, brass, etc. The resolution of the electrode is 6 IG tofts/sm.

The support is made of t-lamifux, which has a small coefficient of friction and is slightly more abrasive than the electrodes. At this time, it is important that the thermal diffusion coefficient A of the support inside the electrode pair is smaller than that outside. The value of A=k/dc (k: thermal conductivity, d: density, C: specific heat) is 1 x 106 ta"/s, and the inner support 22 is less than 5 x lO", and IXlG
"The following is more preferable. Also, A on the outside of the electrode pair is lxl
O' or more, more preferably sx+os or more. The material of such a support body has various types of scratches, etc. inside the electrode pair.
Minerals such as mica lamifuchus, ramifukusu, crystallizing ramifukus, kaolin, and talc are used. On the outside of the electrode pair, BN or ALN-based lamifux (for example, ALN-BN composite material), alumina, laminate, or solid lubricants with high electrical resistance are also used.

Note that, although one of the electrode pairs is an individual signal electrode and the other is a common electrode, the common electrode does not necessarily have to be divided.

Next, the driving method will be described.

A signal current path applied between electrodes 23a and 23b flows through the resistive layer parallel to the membrane. The recording conditions at this time were that the applied pulse width for one shift was 1 ms, the recording period for one line was 4 ms, and the heat generating part's peak temperature was 300-40 x 106.
Reach C. Generally, the current density distribution, ie, the peak temperature distribution, is particularly large in the vicinity directly below the stylus electrode, but in the configuration of the present invention, the temperature distribution becomes uniform between the electrode pair, and a nearly rectangular recording tip can be obtained. Furthermore, since the 8° distance between head heat storage and heat radiation can be removed, high-sensitivity, high-quality images can be obtained. Under such high temperature and pressure (3Kg/loOc
m) Underneath, the ink cartridge 3 and the image receptor 4 are
Travel between Heft°. In order to make effective use of the liquid as needed, the relative velocity is recorded between the image receiving paper and the sheet. It has been experimentally found that in order to be able to record smooth running between the heft and the φ, the coefficient of friction between the two is required to be 0.2 or less at room temperature. In order to promote this, the head may be configured so that the lubricant flows out from the head surface at high temperatures, or conversely, the lubricant may flow out from the resistive liquid.

More specific examples will be described below.

(1) Current-carrying head: A6 line head, resolution 8 ft/am (stylus electrode material is tank stainless steel), electrode pair inside (mica laminate insulating support, electrode pair outer support material is BN)
-ALNI combination lamifukus. Innokawa Harus width 1
ms1 Recording cycle 4ms/line, Pressure 3Kg
/100mm constant velocity recording and relative velocity recording. (Speed ratio n=1-10) (2) Resistance sheet: A film made of aramid resin mixed with carne and having a thickness of lOμ and a surface resistance of IKI.

(3) Coloring material layer: Formed to a thickness of 2 μm with a solid weight ratio of 1 part indaniline-based cyan sublimable dye to 1 part polymeric wood nate resin.

(4) Image receptor: 100μ milky white PET film with 1 part Nyester resin and 0.2 parts silica in a solid weight ratio of 8μ
Formed to a thickness of

As a result of recording experiments under the above conditions, the recording period was 4 m.
There was no fog in the image when recording at 12 degrees with s/5 medium and 2J/ClI12, and smooth gradation recording characteristics were obtained using the relative speed method. This recorded image has an image quality equivalent to that of dye transfer recording using No. 1 square foot as the recording means. In addition to the above-mentioned dyes, a full-color image of AB size could be obtained in about 10 seconds by using 10 colors of maternity and black.

Effects of the invention (l) High-speed, high-sensitivity full-color recording with a 1-line recording speed of 4 ffls1 and a recording energy of 2 J/cm has become possible.

(2) A large and homogeneous recording shaft can be formed.

(3) There is no color turbidity and the image is sharp.

(4) A relative speed ratio of 10 is obtained under the above recording conditions.

[Brief explanation of drawings]

The figure is a sectional view showing a state of recording using a current-carrying head in an embodiment of the present invention. 2... Current carrying head', 21.22... Insulating support, 23a, 23b... Electrode pair.

Claims (3)

[Claims] (1) A current-carrying head in which a pair of opposing electrodes is embedded in an insulating support, characterized in that the thermal diffusion coefficient of the insulating support inside the electrode pair is smaller than that of the outside. (2) Thermal diffusion coefficient of the insulating support inside the electrode pair is 5×10
2. The current-carrying head according to claim 1, wherein the current-carrying head is less than ^6 m^2 s^-^1. (3) Thermal diffusion coefficient between the electrode and the outer insulating support is 1×10
2. The current-carrying head according to claim 1, wherein the current-carrying head is ^6 m^2 s^-^1 or more.