JPH04282292A - Thermal multi-color recording method - Google Patents

Abstract

PURPOSE:To record a multi-color image through one thermosensitive recording processing. CONSTITUTION:In a thermosensitive color recording sheet 11, a thermosensitive cyan-forming layer, a thermosensitive magenta-forming layer, and a thermosensitive yellow-forming layer are successively provided from a substrate side. At the time of thermal recording, while a platen drum 10 is fully rotated once, the thermosensitive color recording sheet 11 is passed through positions of a thermal head 18 and an optical fixer 20 only once. Each heating element of the thermal head generates a thermal energy in accordance with a color to be recorded. The thermosensitive yellow-forming layer is singly allowed to form a color. The thermosensitive yellow-forming layer and the thermosensitive magenta-forming layer are simultaneously allowed to form a color. The thermosensitive yellow-forming layer, the thermosensitive magenta- forming layer, and the thermosensitive cyan-forming layer are simultaneously allowed to form a color. The thermosensitive color recording sheet forms a color in the range of yellow, orange, red, and black in accordance with the thermal energy.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive multicolor recording method that is easy to record.

0002

2. Description of the Related Art There are two types of thermal recording: a thermal recording method and a thermal transfer recording method. The thermal recording method is widely used because it does not generate waste and has low running costs. Recently, for example, JP-A-61-21316
As described in Publication No. 9, a color thermosensitive recording material in which a magenta thermosensitive coloring layer, a cyan thermosensitive coloring layer, and a yellow thermosensitive coloring layer are successively layered on a support to directly record a full-color image. is proposed.

When recording a multicolor image on the color thermosensitive recording material, a yellow image is thermally recorded on the yellow thermosensitive coloring layer using a thermal head, and after this thermal recording, only the uncolored diazo substance in the yellow layer is decomposed. The yellow thermosensitive coloring layer is photofixed by irradiating light from a light source through a filter that passes light of the same wavelength. Next, a cyan image is thermally recorded on the cyan thermosensitive coloring layer, and then light from a light source is irradiated through a filter that passes light with a wavelength that decomposes only the uncolored diazo substance in the cyan layer. Fix with light. lastly,
After thermally recording the magenta thermosensitive coloring layer, the magenta thermosensitive coloring layer is photofixed through a filter that passes light of a wavelength that decomposes only the uncolored diazo substance in the magenta layer.

0004

The above-mentioned thermosensitive multicolor recording method requires three thermal recordings and three optical fixations, so there is a problem in that thermal recording takes a long time. Also,
Since one light source is used and the wavelength to be transmitted is selected by a filter, there is a problem in that the light energy cannot be used effectively and the fixing time becomes longer due to the decrease in light energy. On the other hand, in OHP hard copies and false color hard copies, continuous tone color images are often unnecessary. Even when these hard copies are produced exclusively, three thermal recordings are still required using the above-mentioned thermal multicolor recording method. SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal multicolor recording method that allows a multicolor image to be recorded in one thermal recording.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides that, in one thermal recording, only the surface heat-sensitive coloring layer,
Alternatively, a plurality of heat-sensitive coloring layers may be simultaneously colored to record a multicolor image. If optical fixing is required, it may be carried out once after one thermal recording.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a platen drum 10 holds a color thermosensitive recording sheet 11 on its outer periphery and is continuously rotated in the sub-scanning direction indicated by the arrow by a pulse motor (not shown) during thermal recording. The leading end of the color thermosensitive recording sheet 11 is fixed to the platen drum 10 by a gate-shaped clamp member 12. This clamp member 12 is
The long holes 12a and 12b fit into the platen shaft 13 and pin 14, respectively. Normally, it is in a clamped state with a spring 15, and when the solenoid 16 is energized, the clamp member 12 moves forward to release the clamped state.

A thermal head 18 in which a large number of heat generating elements are arranged in a line is disposed around the outer periphery of the platen drum 10, and the heat generation amount of these heat generating elements is controlled by a head drive unit 19 according to the image data of the pixels. is controlled. The optical fixing device 20 includes a lamp 21 and a reflector 22, and is configured to apply electromagnetic waves such as ultraviolet rays to the color thermosensitive recording sheet 11.
The heat-recorded heat-sensitive coloring layers are simultaneously photofixed.

In FIG. 2 showing the layer structure of the color thermosensitive recording sheet 11, a cyan thermosensitive coloring layer 2 is placed on a support 25.
6, Magenta thermosensitive coloring layer 27, Yellow thermosensitive coloring layer 28
are arranged in successive layers. As this support 25, opaque coated paper or plastic film is used. Furthermore, when producing an OHP sheet, a transparent plastic film is used.

The cyan thermosensitive coloring layer 26 contains an electron-donating dye precursor and an electron-accepting compound as main components, and develops a cyan color when heated. Magenta thermosensitive coloring layer 2
No. 7 contains a diazonium salt compound having a maximum absorption wavelength of about 365 nm and a coupler that thermally reacts with the diazonium salt compound to develop a magenta color. When this magenta thermosensitive coloring layer 27 is irradiated with ultraviolet light around 365 nm, the diazonium salt compound photodecomposes and the coloring ability is lost. The yellow thermosensitive coloring layer 28 has a maximum absorption wavelength of approximately 420 nm.
It contains a diazonium salt compound, which is a diazonium salt compound, and a coupler that develops a yellow color by thermally reacting with the diazonium salt compound. This yellow thermosensitive coloring layer 28 loses its coloring ability when it is irradiated with near ultraviolet light around 420 nm. In addition, each heat-sensitive coloring layer 2
The specific configurations of Nos. 6 to 28 are explained in detail in Japanese Patent Application No. 2-89384 previously filed by the present applicant.

FIG. 3 shows the coloring characteristics of each of the thermosensitive coloring layers 26 to 28. The horizontal axis represents the coloring heat energy generated by the heating element of the thermal head 18, and the coloring heat energy of the yellow thermosensitive coloring layer 28 is the smallest.
The coloring heat energy of the cyan thermosensitive coloring layer 26 is the highest. Note that under normal storage conditions, the cyan coloring layer 26 does not have any photofixability because it does not reach the coloring heat energy of cyan. If necessary, a diazonium salt compound and a coupler fixed by light in a different wavelength range may be used.

Next, the operation of the above embodiment will be explained. After energizing the solenoid 16 to move the clamp member 12, the leading end of the color thermosensitive recording sheet 11 is inserted between the clamp member 12 and the platen drum 10. When the solenoid 16 is turned off, the clamp member 12 is moved back by the spring 15 and clamps the leading end of the color thermosensitive recording sheet 11.

After setting the color thermosensitive recording sheet 11,
Rotate the platen drum 10. When the leading edge of the color thermosensitive recording sheet 11 reaches the position of the thermal head 18, the head driving section 19 drives the thermal head 18 to start thermal recording. In this thermal recording, each heating element of the thermal head 18 generates heat in accordance with image data, causing each pixel of the color thermosensitive recording sheet 11 to develop a desired color. For example, if the thermal energy of the heating element is small,
Only the yellow thermosensitive coloring layer 28 develops color, when the color is medium, the yellow thermosensitive coloring layer 28 and the magenta thermosensitive coloring layer 27 develop color, and when the color is large, the three types of thermosensitive coloring layers 28, 2
7 and 26 develop color at the same time.

When the area on which the multicolor image is recorded reaches the optical fixing device 20, it is irradiated with ultraviolet rays of about 365 to 420 nm. The ultraviolet rays photodecompose the diazonium salt compound contained in the yellow thermosensitive coloring layer 28 and the magenta thermosensitive coloring layer 27, so that the coloring ability of each thermosensitive coloring layer 28, 27 is lost. In this way, the platen drum 10
Thermosensitive recording and optical fixing are performed in one rotation of the drum. After this,
The solenoid 16 is energized to move the clamp member 12 to the clamp release position, and the thermally recorded color thermosensitive recording sheet 11 is removed from the platen drum 10.

FIG. 4 shows the relationship between the heat energy for color development and the color developed. When the coloring heat energy is small, only the yellow coloring layer 28 is colored, and the color ranges from light yellow to deep yellow depending on the coloring heat energy. When the coloring energy is medium, the yellow thermosensitive coloring layer 28 develops color to the maximum density, and the magenta thermosensitive coloring layer 27 develops color in accordance with the thermal energy. Therefore, the yellow thermosensitive coloring layer 28 and the magenta thermosensitive coloring layer 27 produce colors in the range of orange to red. When the coloring heat energy is high, the cyan thermosensitive coloring layer 26 starts to develop color, so the color changes from red-black to black.

In the above embodiment, the yellow thermosensitive coloring layer 28, the magenta thermosensitive coloring layer 27, and the cyan thermosensitive coloring layer 26 are arranged in order from the surface layer, but this order is preferably determined depending on the required color. For example, if the uppermost layer is a yellow thermosensitive coloring layer and the next layer is a cyan thermosensitive coloring layer, the colors change from yellow to green to black depending on the coloring heat energy. Further, if the uppermost layer is a cyan thermosensitive coloring layer and the next layer is a magenta thermosensitive coloring layer, the color changes from cyan to blue to black depending on the coloring heat energy. In addition,
There are six combinations of coloring layers.

FIG. 5 shows a color thermosensitive recording sheet having a two-layer structure. In the example shown in (A), the support 3
0, a magenta thermosensitive coloring layer 31 and a cyan thermosensitive coloring layer 32
are layered one after another, and the color develops in the range of cyan to blue depending on the coloring heat energy. The embodiment shown in (B) is used as an OHP sheet, for example, and has a magenta thermosensitive coloring layer 35 and a cyan thermosensitive coloring layer 36 layered on the upper side of a transparent support 34. This color thermosensitive recording sheet develops colors in the range of magenta to blue depending on the heat energy for color development. There are six types of color thermosensitive recording sheets with this two-layer structure, and the colors produced differ depending on the type.

[0017]

[Effects of the Invention] As explained above, the thermal multicolor recording method of the present invention records a multicolor image in one thermal recording by applying thermal energy according to the color to be developed. ,
Hard copies with a limited number of colors can be produced quickly and easily. In addition, when optical fixing is required, optical fixing is simple as only one electromagnetic wave irradiation is required, and there is no need to select the wavelength with a filter, so optical energy can be used effectively. can.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a thermal multicolor recording apparatus that implements the present invention.

FIG. 2 is an explanatory diagram showing a color thermosensitive recording sheet with a three-layer structure.

3 is a graph showing the coloring characteristics of the color thermosensitive recording sheet shown in FIG. 2. FIG.

FIG. 4 is an explanatory diagram showing the relationship between color development heat energy and color.

FIG. 5 is an explanatory diagram showing a color thermosensitive recording sheet having a two-layer structure.

[Explanation of symbols]

10 Platen drum 11 Color thermosensitive recording sheet 18 Thermal head 20 Optical fixing device 25, 30, 34 Support body 26, 32, 36 Cyan thermosensitive coloring layer 27, 31, 3
5 Magenta thermosensitive coloring layer 28 Yellow thermosensitive coloring layer

Claims (1)

[Claims] [Claim 1] At least two types of thermosensitive coloring layers that develop different colors are sequentially formed on a support, and these thermosensitive coloring layers use a color thermosensitive recording material in which coloring heat energy is higher as the layer goes deeper. By applying coloring thermal energy corresponding to the color to be recorded to this color thermosensitive recording material and coloring only the surface thermosensitive coloring layer or two types of thermosensitive coloring layers at the same time, it is possible to perform coloring once with a thermal head. A thermal multicolor recording method characterized in that a multicolor image is recorded by thermal recording.