Multicolor imaging material

A multicolor imaging material comprises a substrate, a capsule layer made up of a plurality of heat-meltable microcapsules including color former and a developer material layer. When the laser beams having wavelengths of .lambda..sub.1, .lambda..sub.2, and .lambda..sub.3 are applied to the multicolor imaging material according to the signals corresponding to three primary colors, the heat-meltable microcapsules for individual colors independently generate heat, thereby causing the heat-meltable substance to be melted. This brings about the reaction of the color formers for individual colors with the developer to developer colors, thereby forming a color image comprised of cyan, magenta and yellow.

BACKGROUND OF THE INVENTION 
1 Field of the Invention 
The present invention relates to an imaging material and more particularly, 
to multicolor imaging material for imaging multicolor images utilizing a 
plurality of infrared rays having different wavelengths. 
2. Description of the Prior Art 
Recording systems such as electron photography, electrostatic recording, 
current application recording, heat-sensitive recording, ink jet, etc. 
have been heretofore known for forming multicolor images. Further, much 
research has been conducted to develop recording systems utilizing 
microcapsules, and various systems such as a pressure sensitive recording 
system, a heat-sensitive recording system and so on have already been 
invented. A number of patents concern such recording system are disclosed, 
for example, in U.S. Pat. Nos. 4,399,209, 4,440,849, 4,501,809, 4,621,040 
and so on. 
U.S. Pat. No. 4,399,209 is directed to a transfer imaging system which 
comprises a layer of microcapsules wherein a chromogenic material is 
encapsulated with a photosensitive composition. The photosensitive 
composition comprises a radiation-curable composition which upon exposure 
causes an increase in its viscosity thereby preventing diffusion of the 
chromogenic material upon rupture of the capsule. Upon rupture of the 
capsules, those capsules in which the radiation-curable material is not 
activated will release the chromagenic material which will transfer to a 
developer sheet and react with the developer material to from the image. 
Similar imaging systems, i.e., a so-called self-contained imaging sheet 
wherein the developer and the photosensitive encapsule are carried on a 
single substrate, is are described in U.S. Pat. No. 4,440,846. 
A color imaging system employing the aforementioned photosensitive 
composition encapsulated in pressurerupturable microcapsules is described 
in British Pat. No. 2113860. 
British Pat. No. 2113860 discloses a photosensitive material useful in full 
color imaging comprising a support having on the surface thereof 
microcapsules which individually contain cyan, magenta and yellow color 
formers and photosensitive compositions having distinctly different 
sensitivities. A uniform mixture of the microcapsules is distributed over 
the surface of the support. Images are formed by separating the red, green 
and blue components of the image to be reproduced and translating these 
components into different wavelengths of actinic radiation to which the 
photosensitive compositions are distinctly sensitive. The photosensitive 
material is image-wise exposed to the translated radiation and thereafter 
it is subjected to a uniform rupturing force, such as pressure, which 
causes the microcapsules in the underexposed and unexposed areas to 
rupture and release the color formers. The color formers then react with a 
developer material which is contained on the same or a different support 
and produce a full color image. 
In these conventional techniques, the ink jet method involves a problem of 
clotting and is not sufficiently reliable, the other recording methods 
require many complicated steps for recording the three primary colors 
repeatedly from CRT, etc. In particular, since the conventional recording 
material using capsules coloration recording is carried out by reacting 
one coloring component incorporated in the capsules with the other 
coloring component present outside the capsules through the rupture of 
capsule walls caused by applied pressure, a pressure roll which has a 
force of 200-400 pounds per linear inch to break the capsules is needed. 
SUMMARY OF THE INVENTION 
In order to solve such disadvantage, the present invention aims at 
providing multicolor imaging materials from which multicolor images can be 
obtained in a simple process at a high speed utilizing a plurality of 
infrared rays having different wavelengths. 
Therefore, an object of the present invention is to provide an imaging 
material which causes color formation utilizing a plurality of infrared 
rays having different wavelengths. 
Another object of the present invention is to provide an imaging material 
from which multicolor images can be obtained in a simple process at a high 
speed. 
Another more particular object of the present invention is to provide a 
method for forming an image which is feasible without rupturing capsules 
by pressure application. 
An imaging material in accordance with the present invention comprises a 
substrate having on one surface thereof, a capsule layer comprising a 
plurality of heat-meltable microcapsules and a developer material on the 
substrate. 
The multicolor imaging material of the present invention comprises 
microcapsules having double capsule walls, the inner capsule wall being a 
porous membrane, the outer capsule wall being composed of a heat-meltable 
substance or a porous membrane. The microcapsule contains an infrared 
absorbent which is present in either the inner capsule wall or the outer 
inner wall. The multicolor imaging material comprises a substrate coated 
on one surface thereof with an encapsulated composition consisting 
essentially of an electron donating chromogenic material (hereinafter 
referred to as "color former") dissolved in an organic solvent. The color 
former may be soaked in a micro-globule. The micro-globule may be 
contained in the heat-meltable substance and is wrapped in the infrared 
absorbent. That is, the infrared absorbent can be present in the porous 
membrane or in the heat-meltable substance. The imaging material of the 
present invention is stable during normal handling and under general 
conditions, but if it is exposed to the infrared ray which is translated 
from red, green and blue images, the microcapsule is heated through 
adsorption of the infrared rays and the outer capsule wall is melted. As a 
result of the melting of the outer capsule wall, the color former 
contained in the internal phase passes through the inner capsule wall 
composed of the porous membrane and oozes out, or the coloring component 
(hereinafter referred to as "developer material") present outside the 
capsules passes through the capsule wall and permeates into the inside of 
individual capsules. Whether in the former case or in the latter case, 
color formation takes place. Accordingly, forming color can be caused by 
heating in the heated area.

DETAILED DESCRIPTION OF THE INVENTION 
The imaging material according to the present invention comprises a 
substrate having provided thereon a capsule layer comprising a plurality 
of heat-meltable microcapsules and a developer material for reacting with 
a color former contained in the microcapsules to form colors. The 
heat-meltable microcapsule has a capsule wall including an infrared 
absorbent. The capsule has double capsule walls comprising an inner and 
outer capsule wall. The inner capsule wall is composed of porous membrane 
or heat-meltable substance. The infrared absorbent to be used in the 
present invention includes a substance which absorbs an infrared ray of 
specified wavelength for causing coloring reaction but which subslantially 
does not absorb an infrared ray of different wavelength for causing 
another coloring reaction. That is, the color former such as leuco dye 
reacts with the developer material to produce the color by absorbing the 
infrared ray of specified wavelength. The imaging material according to 
the present invintion enables production of multicolor images at high 
speed in a simple process utilizing a plurality of infrared rays, 
characterized by using multicolor imaging materials comprising a substrate 
having provided thereon at least two microcapsules or porous 
micro-globules separately containing therein leuco dyes of respective 
colors capable of forming at least two different colors and color 
developers for reacting with the leuco dyes to form colors and, also 
characterized in that these at least two microcapsules or porous 
micro-globules contain infrared absorbents having different wavelengths 
for the respective colors in the inner capsule wall wrapping leuco dyes or 
in the outer capsule wall comprising a porous membrane or a heat-meltable 
substane. 
Hereafter the present invention will be described with reference to the 
drawings. 
FIG. 1 illustrates an example of microcapsules according to the present 
invention. The microcapsule contains a lueco dye as core material 1, an 
infrared absorbent 3 and a heat-meltable substance 4. The heat-meltable 
microcapsule has double capsule walls comprising a porous membrane 2 as an 
inner capsule wall and the heat-meltable substance 4 as an outer capsule 
wall. The outer capsule wall may be a porous membrane. FIG. 2 shows a 
heat-meltable microcapsule which has an inner capsule wall formed by a 
porous membrane 2 including an infrared absorbent 3. In FIG. 2, the 
capsule wall 2 is enwrapped with a porous membrane or a heat-meltable 
substance. FIG. 3 illustrates an example of porous micro-globules in 
accordance with the present invention. In FIG. 3, the porous 
micro-globules 5 contain a lueco dye 1 enwrapped in a porous membrane or a 
heat-meltable substance 6. The porous membrane or heat-meltable substance 
contains an infrared absorbent 3. 
FIG. 4 shows an example of constructing a multicolor imaging material of 
the present invention using the microcapsules shown in FIG. 1 or 2, or the 
porous micro-globules shown in FIG. 3. A developer material layer 40 which 
reacts with the lueco dyes to form colors is coated on substrate 41 and, 
three kinds of microcapsules or porous micro-globules containing cyan 
lueco dye 44, magenta lueco dye 45 and yellow lueco dye 46 are coated as a 
homogeneous mixture thereon. The microcapsules or porous micro-globules of 
cyan, the microcapsules or porous micro-globules of magenta and the 
microcapsules or porous micro-globules of yellow contain infrared 
absorbent 47 having a wavelength of .lambda..sub.1, infrared absorbent 48 
having a wavelength of .lambda..sub.2 and infrared absorbent 49 having a 
wavelength of .lambda..sub.3, respectively, at the respective walls or 
surfaces thereof. 
FIG. 5 shows an example of a sketchy multicolor recording using the 
multicolor imaging material shown in FIG. 4. Upon exposure to infrared 
rays having wavelengths of .lambda..sub.1, .lambda..sub.2 and 
.lambda..sub.3 in response to signals of the three primary colors from a 
CRT, etc., the microcapsules or porous micro-globules 43 of cyan, magenta 
and yellow are heated correspondingly to the respective wavelengths, 
whereby the leuco dyes contained in the respective microcapsules or porous 
micro-globules react with the color developers 42 and cyan color portion 
50, magenta color portion 51 and yellow color portion 52 are thus recorded 
to facilitate recording of multicolor images. In other words, when the 
infrared rays having wavelengths of .lambda..sub.1, .lambda..sub.2, and 
.lambda..sub.3 are applied to the imaging material according to the 
signals corresponding to the three primary colors, e.g., a CRT, the 
heat-meltable microcapsules for individual colors independently generate 
heat, thereby causing the heat-meltable substance to be melted. This 
brings about the reaction of the color former for individual colors with 
the developer to develop colors, thereby forming a color image comprised 
of cyan, magenta, and yellow. Three primary colors, i.e., red, green and 
blue component images translate into infrared rays having wavelength of 
.lambda..sub.2, and .lambda..sub.3, infrared rays having wavelength of 
.lambda..sub.1 and .lambda..sub.3 and infrared rays having wavelength of 
.lambda..sub.1 and .lambda..sub.2, respectively. 
As methods for producing the microcapsules or porous micro-globules of the 
present invention, there can be employed known microencapsulation and 
surface modification, for example, coacervation method (a phase separation 
method from an aqueous solution such as disclosed in U.S. Pat. Nos. 
2,800,457 and 2,800,458), an interfacial polymerization method, an in situ 
method by monomer polymerization, spray drying proposed in U.S. Pat. No. 
3,111,407, inorganic wall microencapsulation and a 
fusion-dispersion-cooling method such as disclosed in British Pat. No. 
952807. Other suitable methods may be optionally employed. In particular, 
interface polymerization, in situ polymerization, etc. are preferred as 
the method for forming the porous membrane. An example of the method for 
producing double well microcapsules includes a method which comprises 
microencapsulating an organic solvent containing leuco dyes by interface 
polymerization, then mixing the microcapsules with a synthetic resin 
emulsion containg the infrared absorbents to make capsule slurry and then 
spray drying the slurry to effect double-wall microencapsulation. Further 
an example of the surface modification of the porous micro-globules 
includes a method which comprises mixing porous micro-globules immersed in 
an organic solvent containing leuco dyes with a synthetic resin emulsion 
containg infrared absorbents to make a capsule slurry and then spray 
drying the slurry to modify the surface. 
Examples of the substances which construct the microcapsules in the present 
invention include polyamide, polyester, polyurea, polyurethane, 
urea-formaldehyde resin, melamine resin, etc. as the porous membrane and 
as the heat-meltable substance, resins having a low melting point such as 
ethylene-acrylate copolymers, butadiene-styrene copolymers, polyvinyl 
acetate, etc. Further examples of the porous micro-globules include nylon, 
polyethylene, etc. 
Examples of the infrared absorbents in the present invention include 
organic compounds such as cyanine dyes, diamine type metal complexes, 
dithiol type metal complexes, etc. and inorganic compounds such as zinc 
silicate, magnesium silicate, barium sulfate, barium carbonate, etc. 
As the leuco dyes which can be employed in the present invention there can 
be fluorane derivatives, triphenylmethane derivatives, phenothiazine 
derivatives, auramine derivatives, spiropyrane derivatives, etc. and 
specific examples include crystal violet lactome, 
3,3-bis(p-dimethylaminophenyl)phthalide, 
3,3-bis(p-dimethylaminophenyl)-6-aminophthalide, 
3,3bis(p-dimethylamino-phenyl)-6-nitrophthalide, 
3,3-bis(p-dimethylamino-phenly)-6-chlorophthalide, 
3-dimethylamino-6-methoxyfluorane, 3-dimethylamino-5,7-dimethylfluorane, 
3-diethylamino-5,7-dimethylfluorane, 3-diethylamino-5,7-dimethylfluorane, 
3-diethylamino-7-methylfluorane, 3,6-bis-.beta.-methoxyethoxyfuluorane, 
3,6-bis-.beta.-cyanoethoxyfluorane, benzoyl leuco methylene blue, 
rhodamine B lactam, 3-CP-aminophenyl-phthalide, etc. 
Examples of the organic solvent which can dissolve the leuco dyes of the 
present invention include alkylated naphthalenes, alkylated biphenyls, 
alkylated terphenyls, chlorinated paraffins, etc. 
Examples of the developer material which can be used in the present 
invention include phenolic compounds such as .alpha.-naphthol, 
.beta.-naphthol, resorcine, hydroquinone, catechol, pyrogallol, etc., 
activated clay, organic carboxylic acid metal salts, etc. 
As the substrate used in the present invention, there are paper, synthetic 
paper, synthetic resin films, etc. 
The multicolor imaging material of the present invention can be coated onto 
the substrate using a binder. 
Examples of the binder include polyvinyl alcohol, methyl cellulose, 
carboxymethyl cellulose, styrene-butadiene latex, etc. 
For coating the multicolor imaging material of the present invention, there 
can be employed a bar coater, a roll coater, a blade coater, an air knife 
coater, etc. 
As infrared rays for recording in accordance with the present invention, 
there can be employed a solid laser such as YAG laser, etc.; a gas laser 
such as a carbon dioxide laser, etc.; an infrared laser such as a 
semi-conductor laser, etc. 
Hereafter the present invention will be described referring to the examples 
below but is not deemed to be limited thereto. 
EXAMPLE 1 
Microcapsules A 
To 45 parts by weight of diisopropylnaphthalene having dissolved therein 5 
parts by weight of terephthalic acid dichloride were added 1.4 parts by 
weight of benzoyl leuco methylene blue to dissolve. The benzoyl leuco 
methylene blue solution was mixed with an aqueous solution of 3 parts by 
weight of polyvinyl alcohol in 97 parts by weight of water and the mixture 
was emulsified and dispersed with a homogenizer to give a dispersion 
having a mean particle diameter of 10.mu.. An aqueous solution of 3 parts 
by weight of diethylene triamine and 3 parts by weight of sodium carbonate 
in 24 parts by weight of water was added to the dispersion. The mixture 
was allowed to stand for 24 hours while stirring to give a capsule 
solution containing benzoyl leuco methylene blue as a core substance. 
Next, the microcapsules were collected by filtration and, 50 parts by 
weight of the microcapsules were mixed with 50 parts by weight of zinc 
silicate, 10 parts by weight of styrene-butadiene latex and 150 parts by 
weight of water. The mixture was stirred to give a capsule slurry. The 
capsule slurry was subjected to spray drying using a spray drier for 
experimental use under conditions of an inlet temperature at 130.degree. 
C., an outlet temperature at 80.degree. C., a pressure of 3.0 kg/cm.sup.2 
and a solution feed rate of 7 ml/min to obtain Microcapsules A containing 
zinc silicate in the wall and benzoly leuco methylene blue as the core 
substance. 
Microcapsules B 
To 45 parts by weight of diisopropylnaphthalene having dissolved therein 5 
parts by weight of terephthalic acid dichloride were added 1.4 parts by 
weight of rhodamine B lactam to dissolve. The rhodamine B lactam solution 
was mixed with an aqueous solution of 3 parts by weight of polyvinyl 
alcohol in 97 parts by weight of water and the mixture was emulsified and 
dispersed with a homogenizer to give a dispersion having a mean particle 
diameter of 10.mu.. An aqueous solution of 3 parts by weight of diethylene 
triamine and 3 parts by weight of sodium carbonate in 24 parts by weight 
of water was added to the dispersion. The mixture was allowed to stand for 
24 hours while stirring to give a capsule solution containing rhodamine B 
lactam as a core material. 
Next, the microcapsules were collected by filtration and, 50 parts by 
weight of the microcapsules were mixed with 50 parts by weight of barium 
sulfate, 10 parts, by weight of styrene-butadiene latex and 150 parts by 
weight of water. The mixture was stirred to give a capsule slurry. The 
capsule slurry was subjected to spray drying using a spray drier for 
experimental use under conditions of an inlet temperature at 130.degree. 
C., an outlet temperature at 80.degree. C., a pressure of 3.0 kg/cm.sup.2 
and a solution feed rate of 7 ml/min to obtain Microcapsules A containing 
barium sulfate in the wall and rhodamine B lactam as the core material. 
Microcapsules C 
To 45 parts by weight of diisopropylnaphthalene having dissolved therein 5 
parts by weight of terephthalic acid dichloride were added 1.4 parts by 
weight of 3-CP-aminophenyl phthalide to dissolve. The 3-CP-aminophenyl 
phthalide solution was mixed with an aqueous solution of 3 parts by weight 
of polyvinyl alcohol in 97 parts by weight of water and the mixture was 
emulsified and dispersed with a homogenizer to give a dispersion having a 
mean particle diameter of 10.mu.. An aqueous solution of 3 parts by weight 
of diethlene triamine and 3 parts by weight of sodium carbonate in 24 
parts by weight of water was added to the dispersion. The mixture was 
allowed to stand for 24 hours while stirring to give a capsule solution 
containing 3-CP-aminophenyl phthalide as a core material. 
Next, the microcapsules were collected by filtration and, 50 parts by 
weight of the microcapsules were mixed with 50 parts by weight of 
magnesium silicate, 10 parts by weight of styrene-butadiene latex and 150 
parts by weight of water. The mixture was stirred to give a capsule 
slurry. The capsule slurry was subjected to spray drying using a spray 
drier for experimental use under conditions of an inlet temperature at 
130.degree. C., an outlet temperature at 80.degree. C., a pressure of 3.0 
kg/cm.sup.2 and a solution feed rate of 7 ml/min to obtain Microcapsules A 
containing magnesium silicate in the well and 3-CP-aminophenyl phthalide 
as the core material. 
Dispersion 
To 100 parts by weight of 5% polyvinyl alcohol aqueous solution were added 
30 parts by weight of bisphenol A. The mixture was dispersed for 24 hours 
in a ball mill to give a dispersion of bisphenol A. 
To 40 parts by weight of the bisphenol A dispersion were added 20 parts by 
weight of Microcapsules A and 20 parts by weight of Microcapsules B thus 
obtained. The mixture was mixed and made a coating solution. The coating 
solution was coated onto wood free paper of 50 g/m.sup.2 in an amount of 
20 g/m.sup.2 (dry weight) using a wire bar, which was dried to give a 
multicolor imaging material. 
Recording was made on the multicolor imaging material at an output of 1.0 W 
and a scanning rate of 2 m/sec using a carbon dioxide laser having a 
wavelength of 10.6.mu. to give color images having a clear cyan color. 
Next, recording was made at an output of 1.0 W and a scanning rate of 2 
m/sec using a carbon dioxide laser having a wavelength of 9.2.mu. to give 
color images having a clear magenta color. The cyan and magenta color 
images showed no color contamination at all. 
EXAMPLE 2 
A multicolor imaging material was obtained in a manner similar to Example 1 
except that Microcapsules C were used in place of Microcapsules B. 
Recording was made on the multicolor imaging material under the same 
conditions as in Example 1 using a carbon dioxide laser having a 
wavelength of 10.6.mu. and then using a carbon dixode laser having a 
wavelength of 9.6.mu. to give color images having clear cyan and yellow 
colors. The cyan and yellow color images showed no color contamination at 
all. 
EXAMPLE 3 
A multicolor imaging material was obtained in a manner similar to Example 1 
except that Microcapsules C were used in place of Microcapsules A. 
Recording was made on the multicolor imaging material under the same 
conditions as in Example 1 using a carbon dioxide laser having a 
wavelength of 9.2.mu. and then using a carbon dioxide laser having a 
wavelength of 9.6.mu. to give color images having clear magenta and yellow 
colors. The magenta and yellow color images showed no color contamination 
at all. 
EXAMPLE 4 
To 60 parts by weight of a bisphenol A dispersion were added 20 parts by 
weight of Microcapsules A, 20 parts by weight of Microcapsules B and 20 
parts by weight of Microcapsules C in Example 1. The mixture was mixed and 
made a coating solution. The coating solution was coated onto wood free 
paper of 50 g/m.sup.2 in an amount of 20 g/m.sup.2 (dry weight) using a 
wire bar, which was dried to give a multicolor imaging material. 
Recording was made on the multicolor imaging material under the same 
conditions as in Example 1 using carbon dioxide lasers having wavelengths 
of 10.6.mu., 9.2.mu. and 9.6.mu. to give color images having clear cyan, 
magenta and yellow colors. The cyan, magenta and yellow color images 
showed no color contaminating at all. 
EXAMPLE 5 
FIG. 6 is a schematic view of an imaging material according to the present 
arrangement which comprises a substrate coated with porous micro-globules 
each impregnated with a heat-meltable substance containing either one of 
cyan magenta, and yellow color forming lueco dyes dispersed therein, 
enclosed in a material which absorbs a laser beam of a wavelength which 
varies according to the kind of color, and homogeneously mixed with each 
other through the medium of a binder in which a developer material is 
dispersed. 
FIG. 7 is an illustration of the process of recording a multicolor image 
through the exposure of the imaging material as shown in FIG. 6 to laser 
beams. 
When the laser beams having wavelengths of .lambda..sub.1, .lambda..sub.2, 
and .lambda..sub.3 are applied to the imaging material according to the 
signals corresponding to three primary colors, e.g., a CRT, the porous 
micro-globules for individual colors independently generate heat, thereby 
causing the heat-meltable substance to be fused. This brings about the 
reaction of the leuco dyes for individual colors with the developer 
material to develop colors, thereby forming a color image comprised of 
cyan, magenta, and yellow. 
The lueco dyes and developer materials which may be used in the present 
arrangement include the same compounds as given above. 
Examples of the heat-meltable substance include waxes such as paraffin wax, 
montan wax, and polyethlene wax, and low-boiling resins such as 
ethylene-acrylate copolymer and butadiene-styrene copolymer. 
Examples of the laser beam absorbing material include inorganic oxides, 
phthalocyanines, and quaternary ammonium salts. 
In FIG. 6, the developer material and binder 64 which react with the lueco 
dyes 65 to form colors are coated on substrate 62 and, three kind of 
porous micro-globules 63 containing cyan leuco dye, magenta leuco dye and 
yellow lueco dye are coated as a homogeneous mixture thereon. The porous 
micro-globules of cyan, magenta or yellow contain a material 66 capable of 
absorbing a laser beam having a wavelength of .lambda..sub.1, a material 
67 capable of absorbing a laser beam having a wavelength of .lambda..sub.2 
or a material 68 capable of absorbing a laser beam having a wavelength of 
.lambda..sub.3, respectively. The porous micro-globules 63 include the 
lueco dyes and the heat-meltable substance as a core material. In FIG. 7, 
the reference numerals 710, 711 and 712 indicate an oscillator for a laser 
beam having a wavelength of .lambda..sub.1, .lambda..sub.2 and 
.lambda..sub.3, respectively. The reference numerals 79 and 713 indicate 
pinch rollers. An imaging sheet 71 is exposed to three kind of laser beams 
having mutually different wavelengths from the oscillators 710, 711 and 
712, thereby forming a multicolor image in one process. 
EXAMPLE 6 
The other arrangement of the present invention will be described as 
follows. The arrangement directed to a method of exposing a substrate 
coated with a homogeneous mixture of three kinds of microcapsules 
respectively containing either one of cyan, magenta and yellow dyes to a 
laser beam, thereby forming a multicolor image having a high quality at a 
high speed in one process. 
FIG. 8 is a schematic view of a laser color imaging material. In FIG. 8, an 
imaging material 81 comprises a substrate 82 coated with a color 
developing layer 83 containing a developer material uniformly dispersed 
therein and then with a homogeneous mixture of three kinds of micrcapsules 
84 respectively containing core material comprised of a combination of 
either one of cyan-, magenta-, and yellow-developing leuco dyes 85, 86 and 
89 with a corresponding decolorizing agent 86, 88 and 810. The leuco dyes 
and the decolorizing agents as the core materials of the microcapsule are 
enclosed in a resin 811 which fuses at a temperature which varies 
according to the kind of colors to be developed. The three kind of 
microcapsules respectively for cyan, magenta, and yellow each have a 
capsule wall containing a laser beam absorbing material which generates 
heat upon being exposed to a laser beam. 
The present arrangement will be described in more detail. 
The microcapsules respectively for cyan, magenta, and yellow are exposed to 
three kinds of laser beams having mutually different energy levels so that 
they develop colors at e.g., temperatures of T.sub.1, T.sub.2, and T.sub.3 
(T.sub.1 &lt;T.sub.2 &lt;T.sub.3), respectively. The microcapsule for cyan is 
formed so that a cyan decolorizing agent does not fuse until the 
temperature reaches T.sub.2 although a cyan leuco dye fuses at a 
temperature of T.sub.1. In this case, the cyan leuco dye reacts with the 
developer at a temperature of T.sub.1 to develop a color. The 
micro-capsule for magenta is formed so that a magenta decolorizing agent 
does not fuse until the temperature reaches T.sub.3 although a magenta 
leuco dye fuses at a temperature of T.sub.2. In this case, the magenta 
leuco dye reacts with the developer at a temperature of T.sub.2 to develop 
a color. At this temperature, the cyan decolorizing agent fuses in the 
microcapsule for cyan, which prevents the cyan leuco dye from developing a 
color. Further, since the microcapsule for yellow does not develop a color 
until the temperature reaches T.sub.3, only magenta is developed at a 
temperature of T.sub.2. The microcapsule for yellow is formed so that a 
yellow decolorizing agent does not fuse until the temperature reaches 
T.sub.4 (&gt;T.sub.3) although a yellow leuco dye fuses at a temperature of 
T.sub.3. In this case, the yellow leuco dye reacts with the developer at a 
temperature of T.sub.3 to develop a color. At this temperature, the 
decolorizing agents in the microcapsules for cyan and magenta fuse, which 
prevents the cyan, magenta, and yellow leuco dyes from developing colors. 
Thus, the microcapsules respectively for cyan, magenta, and yellow 
independently develop colors at different temperatures, which leads to the 
realization of recording of a multicolor image in one process through 
radiation of three kinds of laser beam having mutually different energy 
levels. 
The lueco dyes which may be used in the present arrangement include 
compounds as described above. 
Examples of the decolorizing agent include polyethylene oxide, 
polyoxydecamethylene oleyl ether, tripropylcarbinol, 
2,5-dimethyl-3-hexy-2,5-diol, and pentamethylglycerin. 
Examples of the developer include phenolic compounds such as 
.alpha.-naphthol, .beta.-naphthol, resorcinol, hyroquinone, catechol, and 
pyrogallol, activated clay, and metal salts of organic carboxylec acids. 
Examples of the heat-meltable substance for enclosing the leuco dye and the 
decolorizing agnt therein include waxes such as paraffin wax, montan wax, 
and polyethylene wax, and low boiling resins such as ethylene-acrylate 
coplymer, butadiene and styrene copolymer. 
Examples of the laser beam absorbing material include inorganic oxides, 
phthalocyanines, and quaternary ammonium salts. 
The process for forming color images employing the sheet is similar to that 
above described as shown in FIG. 7. 
When the laser color recording sheet 81 is exposed to laser beams 
.lambda..sub.1, .lambda..sub.2, and .lambda..sub.3 having mutually 
different energy levels to raise the temperatures respectively to T.sub.1, 
T.sub.2, and T.sub.3, the corresponding microcapsule 84 of the laser color 
recording sheet 81 develops a color to record a multicolor image. 
As has been described hereinabove, the present invention enables production 
of multicolor images at high speed in a simple process utilizing a 
plurality of infrared rays, characterized by using multicolor recording 
materials comprising a substrate having provided thereon at least two 
microcapsules or porous micro-globules separately containing therein color 
formers of respective colors capable of forming at least two different 
colors and color developers capable of reacting with the color formers to 
form colors and, also characterized in that these at least two 
microcapsules or porous micro-globules contain infrared absorbents having 
different wavelengths for the respective colors in the wall or at the 
surface thereof.