JPS62164580A - Thermal recording method - Google Patents

Abstract

PURPOSE:To improve the transparency of the background of recording paper, by treating a thermal recording material wherein a thermal recording layer forming a color under heating and fixed by light with a specific wavelength is provided on a support in the order of thermals recording, optical fixing and re-heating. CONSTITUTION:A coating solution containing a diazo compound and a coupler generating the coupling reaction with said diazo compound at the time of heating to form a color as essencial components and further containing a solid base and waxes is prepared. The aforementioned coating solution is applied to a support to obtain a thermal recording material provided with a thermal recording layer forming a color under heating and fixed by light with a specific wavelength. This thermal recording material is recorded thermally and subsequently subjected to optical fixing using a light source emitting light having a wavelength in the vicinity of the light absorption wavelength of a diazonium salt, for example, a fluorescent lamp. Next, the treated thermal recording layer is reheated to temp. melting the fine particles in said thermal recording layer, pref. 70-200 deg.C to substantially enhance the light transmissivity of a non-printed part.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a thermal recording method, and more particularly to a light-transmissive original that can be used in a copying system using a light-transmissive original such as so-called diazo copy paper. The present invention relates to a method for recording original documents for use with an overhead projector, etc., using a heat-sensitive recording layer.

(Prior art) Conventionally, thermal recording paper has been made by dispersing fine particles of a colorless or light-colored dye called a color former and a color developer that causes a color reaction by eutectic melting when heated. It is obtained by coating on paper or film together with a mouthwash agent and a binder. However, since these heat-sensitive layers themselves have low transparency to light, no matter how transparent the support is,
Transmission Amount The light transmittance is insufficient for a copy machine manuscript, and it cannot be used. Also, it cannot be used at all for applications such as r-bar head projectors, which require higher transparency of unprinted areas.

However, in recent years, systems for thermally recording various types of information using, for example, facsimile machines, CAD% CAMs, printers, etc., have become widespread, and overhead projectors have become popular, allowing these thermal recording papers to be used directly for copying multiple copies of manuscripts. -There has been an increasing demand to use it for manuscripts.

(Objective of the Invention) Therefore, the object of the present invention is to enable recording with a conventional thermal head or thermal pen, and to create a document that can be used as a second original. The goal is to find a way to increase the transparency of the recording paper background to a level where it can be used for printing or overhead manuscripts.

(Structure of the Invention) An object of the present invention is to provide a fixable heat-sensitive recording material having a heat-sensitive recording layer on a transparent or translucent support that develops color by heating and is fixed by light of a specific wavelength. This was achieved using a transmission type heat-sensitive recording method characterized by substantially increasing the light transmittance of the unprinted area by processing it as a thermal recorder, optical fixing, and reheating.

In the present invention, the heat-sensitive recording layer contains as essential components a diazo compound and a coupler which causes a coupling reaction with the diazo compound and develops color when heated. form. Next, by irradiating the printed recording paper with light from a light source having a photodecomposition wavelength of the diazonium salt, the diazonium salt in the unprinted area is photodecomposed and a coloring reaction occurs during subsequent heating. There will be no. In other words, fixation has been performed. Furthermore, in this state, the unprinted area is cloudy and the light from the light source for copying does not pass through sufficiently, so there is no contrast between it and the printed area after passing through, and it cannot be used as a manuscript. do not have. The key point of the present invention is that by further heating the entire surface of the recording paper with an iron, a hot roll, etc., the light transmittance of the unprinted areas can be improved. The reason why the transparency of the unprinted area is significantly improved by post-heating is probably due to the color forming agent and/or developer and/or sensitizer and/or other waxes that were present in the layer in the form of fine particles. It can be inferred that the heat-fusible components such as these melt and form a solid solution in which the individual particle surfaces disappear.

The diazo compounds used in the present invention include diazonium salts, diazosulfonate compounds, diazoamino compounds, etc., and their coupling reaction ability is deactivated by irradiation with light of a specific wavelength. Specifically, S# open open y-iyotrt, special request show! Tar/6231. / etc. are detailed. Further, as for couplers which develop a color by causing a thermal coupling reaction with the diazo compound, those detailed above can be preferably used. In addition, the heat-sensitive layer contains these diazo compounds, couplers, and, if necessary, solid bases, waxes, sensitizers, etc., but at least one of these is a thermofusible component. Therefore, the present invention can be achieved if the average particle size is about 0.2 to IOμ.

Particularly preferably, among the above-mentioned additives, when a diazo compound is contained in the microcapsules, the microcapsules have high resistance to aging, aging after printing, and contact with chemicals.

Photofixing is effectively carried out by irradiation for several seconds with a light source near the light absorption wavelength of the diazonium salt, such as a fluorescent lamp, flash, strobe, cold cathode discharge tube, etc. In some cases, it can be fixed by simply leaving it exposed to sunlight, indoor lighting, etc., but it takes time.

To make it transparent, you can press it with an iron or the like for a few seconds in an off-machine after fixing, or you can heat it in an on-machine by exposing it to a hot roll or hot air after the fixing light source.

These reheating steps are performed at temperatures above the temperature at which the fine particles in the heat-sensitive layer melt, and are usually 70°C to 20°C.
about, more preferably rO°C~/! It is sufficient if it is 0°C.

(Example of the invention) The present invention will be explained in more detail in the following examples.

Example 7 (1) Preparation of solid dispersion of diazo compound The above composition was pulverized and dispersed in a ball mill for 24 hours. Average particle size/! Atsushi in μ.

(2) Preparation of solid dispersion of coupling component The mixture was ground and dispersed in a ball mill for 2 hours. The average particle size was 2μ.

(2) Preparation of solid dispersion of basic substance 2 was pulverized and dispersed in a poly mill for a period of time. Average particle size λμ
Met.

■ Composition of heat-sensitive layer coating liquid After drying, apply the above composition carefully! , j? /y12
I painted it on semi-transparent tracing paper so that it looked like this.

This material was thermally printed using a facsimile (UF-2 manufactured by Matsushita Electronics Co., Ltd.), and then photofixed using a Ricopy High Start≠ type (Ricoh ■!2 type) light source.

One sheet of this recording paper will be used as a manuscript, and the other sheet will be
After reheating with a 8u0C iron for 5 seconds, use it as a manuscript and place it on the Ricoh High Start Hiroo (manufactured by Ricoh ■). Please make sure to use this to copy onto diazo copy paper.

In the copy obtained from the next original after reheating, the printed area was a clear blue color, and the background area was a clear, clean image. On the other hand, in copies obtained from originals that were not reheated, the background part also had the same blue color as the printed part, and was almost impossible to read.

Example 2 The following diazo compound @ λ part and 11 parts of an adduct of xylylene diisocyanate and trimethylolpropane (J:/) were added and dissolved in a mixed solvent of 2 parts of didutyl phthalate and 5 parts of ethyl acetate. This diazo compound solution was mixed with an aqueous solution containing 3.3 parts of polyvinyl alcohol, 7 parts of gelatin, and 1 part of water, and emulsified and dispersed at 206C to obtain an emulsion with an average particle size of 3μ. . Water i to the obtained emulsion
o.

After adding the parts, the mixture was heated to 0°C while stirring, and after 2 hours, the following diazo compound was added to the core substance to obtain a capsule liquid.

(Diazo compound) Next, add 20 parts of naphthol A s and μ parts of the following amide compound! In addition to 100 parts of a polyvinyl alcohol aqueous solution, about 211 was dispersed for a period of time in a sand mill to obtain a dispersion of coupling components with an average particle size of 3μ. 47'? .

(Amide Compound) Next, 20 parts of triphenylguanidine were added to 100 parts of an aqueous polyvinyl alcohol solution and dispersed in a sand mill for about -≠ hours to obtain a dispersion 2 of triphenylguanidine with an average particle size of 3 μm.

Further, 0 parts of p-benzylhydroquinone λ0 parts and 10 parts of 1tJ-% aqueous polyvinyl alcohol solution were dispersed in a sand mill for about 2 hours to obtain a dispersion of p-benzylhydroquinone with an average particle size of 3μ. Obtained.

Capsule liquid of diazo compound obtained by the above process
Dispersion of coupling component in o part/! 1 part, 75 parts of a dispersion of triphenylguanidine, and 3 c parts of a successful product of p-benzylhydroquinone were added to prepare a coating liquid. This liquid,
! Coat it on a transparent polyethylene terephthalate film of Qμ so that it becomes j Ot/TrL2, and
After drying for 0 minutes, a fixed heat-sensitive recording film was prepared.

On the other hand, as a recording device, 7Aximi 1JU manufactured by Matsushita Electronics
Immediately after the paper discharge port of F-J, the fixing light source used in Example 1 was installed, and immediately after that, a heating roll with a diameter of 1OOrrLφ was installed, and the temperature of the heating roll was controlled to t-/xo'C. friend. A specific image is printed, fixed, and reheated by passing the fixing type heat-sensitive recording film through this device.

The image area of the resulting film was black, and the non-image area was almost transparent. On the other hand, when the heating roll was passed through the heating roll at the above i& position without applying heat, a recording film was obtained in which the image area was black and the non-image area was white.

When both were used as manuscripts and subjected to OHP, a clear image was obtained on the screen for the former, but no image could be seen for the latter.

Claims (1)

[Claims] 1. On a transparent or translucent support, color is developed by heating,
A fixable heat-sensitive recording material having a heat-sensitive recording layer that is fixed by light of a specific wavelength is processed in the order of thermal recording, light fixing, and reheating to substantially increase the light transmittance of unprinted areas. Transmission type thermal recording method. 2. Develops color by heating on a transparent or translucent support,
In an apparatus for thermally recording a fixable heat-sensitive recording material having a heat-sensitive recording layer fixed by light of a specific wavelength, the heat recording, optical fixing, and reheating parts are arranged in the order in which the recording material travels. A transmission type heat-sensitive recording device characterized by being arranged in an array.