EP0826512A1 - Thermal transfer recording material heving an intermediate adhesive layer - Google Patents
Thermal transfer recording material heving an intermediate adhesive layer Download PDFInfo
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- EP0826512A1 EP0826512A1 EP97114863A EP97114863A EP0826512A1 EP 0826512 A1 EP0826512 A1 EP 0826512A1 EP 97114863 A EP97114863 A EP 97114863A EP 97114863 A EP97114863 A EP 97114863A EP 0826512 A1 EP0826512 A1 EP 0826512A1
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- Prior art keywords
- adhesive layer
- intermediate adhesive
- thermal transfer
- heat
- weight
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
- B41M5/00—Duplicating or marking methods; Sheet materials for use therein
- B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
- B41M5/40—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography
- B41M5/42—Intermediate, backcoat, or covering layers
- B41M5/44—Intermediate, backcoat, or covering layers characterised by the macromolecular compounds
Definitions
- the present invention relates to a thermal transfer recording medium. More particularly, it relates to a thermal transfer recording medium which does not cause the so-called "ink-falling" and is capable of providing printed images with high definition.
- thermal transfer recording system has been widely applied because thermal transfer printers used therein have characteristics such as easy maintenance, availability of small-sized and lightweight ones and low-cost.
- respective plural heating elements (dots) of a thermal head are allowed to selectively generate heat in response to picture signals, thereby selectively transferring the heat-meltable ink layer of a thermal transfer recording medium in dots to give a printed image on a receptor. Therefore, improved dot-reproducibility is required to obtain printed images with high definition.
- This dot-reproducibility refers to the coincidence of the shape of dots of the transferred heat-meltable ink with that of the heating elements.
- Measures for improving the dot-reproducibility include selection of a heat-meltable material showing a sharp peak in its DSC (differential scanning calorimetry) curve for the vehicle of the heat-meltable ink layer.
- a heat-meltable material showing a sharp peak in its DSC (differential scanning calorimetry) curve for the vehicle of the heat-meltable ink layer.
- carnauba wax penetration: 1
- a heat-meltable ink layer containing carnauba wax as a vehicle thereof offers printed images with improved dot-reproduction because the wax shows a sharp peak in its DSC curve.
- the term "ink-falling” refers to a phenomenon in which, during traveling of the thermal transfer recording medium, which is loaded in a cassette, in a thermal transfer printer, portions of the heat-meltable ink layer are peeled off from the foundation when the recording medium comes into sliding contact with guide members of the cassette, the thermal head, etc. and, hence, is subjected to external force.
- the ink-falling phenomenon is remarkable in using the recording medium in low-temperature environments.
- the ink-falling phenomenon is undesirable because portions of the recording medium wherein the ink layer is peeled off cannot be used to form printed images and the generated ink powder is accumulated in the thermal head, resulting in a decrease in image quality or contamination in the inside of the printer.
- Conventional measures for preventing the ink-falling phenomenon include (1) a method wherein the content of a resin component in the heat-meltable ink layer is increased to improve adhesion of the ink layer, and (2) another method wherein a wax having a greater penetration is used in combination with carnauba wax to impart flexibility or softness to the heat-meltable ink layer.
- the method (1) involves a problem that the viscosity of an ink coating liquid is increased with increasing content of the resin component and, hence, the application property of the coating liquid becomes poor, resulting in failure to form a uniform ink layer.
- the method (2) involves a problem that during exchange of the recording medium in using it in low-temperature environment, the ink thereof sticks to the hand.
- an object of the present invention is to provide a thermal transfer recording medium which causes no ink-falling in low-temperature environments and exerts excellent dot-reproducibility to form printed images with high definition.
- the present invention provides a thermal transfer recording medium comprising a foundation having thereon a heat-meltable ink layer, and an intermediate adhesive layer provided between the foundation and the heat-meltable ink layer, the intermediate adhesive layer comprising 20 to 80 % by weight of a polyester resin having a glass transition temperature of not higher than 20°C, and 20 to 80 % by weight of at least one of a body pigment and carbon black.
- the polyester resin has a glass transition temperature of not higher than 0°C.
- the heat-meltable ink layer comprises a coloring agent and a vehicle, the vehicle comprising not less than 40 % by weight of caranuba wax.
- the vehicle comprises not less than 50 % by weight of carnauba wax.
- the intermediate adhesive layer comprises 40 to 70 % by weight of a polyester resin having a glass transition temperature of not higher than 20°C and 30 to 60 % by weight of at least one of a body pigment and carbon black.
- Fig. 1 is a schematic view illustrating a measuring device for examining the ink-falling of a thermal transfer recording medium.
- the thermal transfer recording medium of the present invention is characterized in that between the foundation and the heat-meltable ink layer is provided an intermediate adhesive layer comprising 20 to 80 % by weight of a polyester resin having a glass transition temperature of not higher than 20°C, and 20 to 80 % by weight of at least one of a body pigment and carbon black.
- the intermediate adhesive layer maintains flexibility or softness even in low-temperature environments wherein the temperature is lower than nornmal temperature because a polyester resin having a glass transition temperature of not higher than 20°C is used as the resin component and, hence, serves as some type of a buffer layer between the foundation and the heat-meltable ink layer, thereby causing no ink-falling even in the case that the heat-meltable ink layer is relatively hard.
- the use of a polyester resin having a glass transition temperature of higher than 20°C as the resin component for the intermediate adhesive layer results in ink-falling because the polyester resin crystallizes in low-temperature environments and the function of the intermediate adhesive layer as a buffer layer is lost. From the viewpoint of retaining the flexibility or softeness of the intermediate adhesive layer in low-temperature environments, a polyester resin having a glass transition temperature of not higher than 0°C is preferable.
- the intermediate adhesive layer is incorporated with at least one of a body pigment and carbon black (hereinafter, in some cases, referred to as "particulate material") in addtion to the polyester resin.
- a body pigment and carbon black hereinafter, in some cases, referred to as "particulate material”
- the incorporation of the particulate material produces fine unevenness on the surface of the intermediate adhesive layer to increase the contact area between the intermediate adhesive layer and the heat-meltable ink layer. As a result, the ink-falling can be more sufficiently prevented.
- the intermediate adhesive layer in accordance with the present invention contains 20 to 80 % by weight, preferably 40 to 70 % by weight, of a polyester resin having a glass transition temperature of not higher than 20°C, and 20 to 80 % by weight, preferably 30 to 60 % by weight, of a particulate material.
- a polyester resin having a glass transition temperature of not higher than 20°C is lower than the above range or the content of the particulate material is higher than the above range, the function of the intermediate adhesive layer as a buffer layer is degraded to fail to sufficiently exert the effect of preventing the ink-falling and a problem that the application property of a coating liquid for the intermediate adhesive layer is degraded is further invited.
- the contact area between the intermediate adhesive layer and the ink layer is not increased due to the lower content of the particulate material to fail to sufficiently exert the effect of preventing the ink-falling and the so-called "layer-like transfer” which refers to the phenomenon wherein an excess portion of the ink layer that is not heated during the thermal transfer is also transferred, is prone to further occur, resulting in deterioration of the dot-reproducibility.
- polyester resin there can be used linear saturated polyester resins which are obtained by polycondensation of a dibasic acid and a diol compound and have a glass transition temperature of not higher than 20°C, preferably not higher than 0°C.
- dibasic acid examples include adipic acid, azelaic acid, sebacic acid, phthalic acid and Het acid (chlorendic acid). These dibasic acids can be used either alone or in combinations of two or more species thereof.
- diol compounds examples include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A and dibromoneopentylene glycol. These diol compounds can be used either alone or in combinations of two or more species thereof.
- body pigments as the particulate material are silica, calcium carbonate, magnesium carbonate, barium sulfate and aluminium silicate. These body pigments can be used either alone or in combinations of two or more species thereof.
- the body pigment and carbon black may be used either alone or in combiantion as the particulate material.
- the particulate material preferably has an average particle size of about 0.5 to about 10 ⁇ m.
- the intermediate adhesive layer may be incorporated with a small amount of a dispersing agent or the like in addition to the aforesaid ingredients.
- the thickness of the intermediate adhesive layer is preferably from 0.3 to 1.0 ⁇ m from the viewpoint of the adhesiveness and the transfer sensitivity.
- the intermediate adhesive layer can be formed by applying onto a foundation a coating liquid which is prepared by dissolving or dispersing the polyester resin and the particulate material into an appropriate solvent, followed by drying.
- the heat-meltable ink layer in accordance with the present invention there can be used conventional ones without particular limitation so long as they are one-time type heat-meltable ink layers each comprising a coloring agent and a heat-meltable vehicle as main ingredients.
- a heat-meltable ink layer whose vehicle component contains not less than 40 % by weight, especially not less than 50 % by weight, of carnauba wax to form printed images having excellent durability with excellent dot-reproducibility as well as to prevent the ink-falling in combination with the aforesaid intermediate adhesive layer.
- the content of carnauba wax in the vehicle component is lower than the above range, the dot-reproducibility is prone to be deteriorated to fail to produce printed images with high definition and the durability of printed images is also prone to be decreased.
- waxes other than carnauba wax and/or resins are waxes other than carnauba wax and/or resins.
- waxes there can be appropriately selected and used those conventionally used in this field, such as paraffin wax, microcrystalline wax, oxidized wax, ester wax, candelilla wax, rice wax and montan wax.
- resins there can be appropriately selected and used those conventionally used in this field, such as polyethylene, ethylene-vinyl acetate resin, polyamide resins, polyester resins, epoxy resins and acrylic resins.
- Carbon black as well as usual pigments and dyes can be appropriately selected and used as the coloring agent.
- Suitable ranges for the contents of the foregoing ingredients in the heat-meltable ink layer in accordance with the present invention are as follows: Ingredient % by weight Carnauba wax 40 to 95 (preferably 50 to 90) Other waxs 0 to 40 (preferably 10 to 30) Resin 0 to 40 (preferably 10 to 30) Coloring agent 5 to 20
- the heat-meltable ink layer in accordance with the present invention can be formed by applying an ink of the foregoing formulation onto the aforesaid intermediate adhesive layer by means of a hot-melt coating method or a solvent coating method.
- the thickness of the heat-meltable ink layer is preferably from 1 to 5 ⁇ m from the viewpoint of the optical density of images and the transfer sensitivity.
- an overcoat layer may be provided on the heat-meltable ink layer.
- the overcoat layer is provided for the purpose of preventing smearing or the like.
- the overcoat layer is an uncolored layer comprising a wax as a main ingredient.
- the foundation in the present invention are highly heat-resistant plastic films such as polyethylene terephthalate film, polycarbonate films, polyimide films and nylon films, and cellophane, parchment paper and condenser paper.
- the thickness of the foundation is usually from 2 to 10 ⁇ m, preferably from 3.5 to 6 ⁇ m. From the viewpoint of good adhesion to the intermediate adhesive layer, polyethylene terephthalate film is especially preferred.
- a heat-resistant layer comprising one or more resins selected from silicone resins, fluorine-containing resins, acrylic resins, epoxy resins, phenol resins, cellulose resins, and the like.
- each composition for intermediate adhesive layer of the formulation shown in Table 1 was added into a mixed solvent of tolune/methyl ethyl ketone so that the total solid concentration became 10 % by weight.
- the resulting mixture was agitated at a high speed in an attritor for 60 minutes to give a coating liquid for intermediate adhesive layer.
- Onto one side of a 6 ⁇ m-thick polyethylene terephthalate film which was provided on the other side thereof with a heat-resistant layer composed of a silicone resin was applied the coating liquid by means of a solvent coater so that the coating amount after drying was 0.5 g/m 2 , followed by drying to give an intermediate adhesive layer.
- the resulting coating liquid failed to form a uniform layer due to its poor application property and, hence, subsequent treatments were not performed.
- Each composition for heat-meltable ink layer of the formulation shown in Table 1 was sufficiently kneaded by means of a 3-roll mill to give a heat-meltalbe ink.
- the ink was applied in a coating amount of 3.0 g/m 2 onto the intermediate adhesive layer by means of a hot-melt coater to give a heat-meltable ink layer.
- Each of the thermal transfer recording media was used to form a printed image under the printing conditions mentioned below.
- the printed image was observed with a metallograph (XF(U)NR made by NIKON CORPORATION) at a magnification of 50 to determine the ratio of the area of one dot of the image to that of one dot of the heating elements (area of one dot of the image/area of one dot of the heating elements).
- the dot-reproducibility was evaluated according to the following criterion:
- the degree of ink-falling was examined in a low-temperature environment (dry room at 0°C ) with use of a measuring device as shown in Fig. 1.
- This test is a substitute for a test for examining the degree of ink-falling when the thermal transfer recording medium is squeezed through a thermal head.
- a glass plate 3 was fixed to a support member 2 which was mounted on a table 1 with projecting out from an edge of the table 1.
- a ribbon-like thermal transfer recording medium 4 (width: 12.7 mm) was arranged so that it lay upward on the ink layer side and was brought into contact with the end surface of the glass plate 3 on the back side thereof.
- a weight 5 was attached to one end of the recording medium that hung down and a movable member 6 was attached to the other end of the recording medium.
- the movable member 6 was moved at a speed of 1.3 m/minute in the direction indicated by the arrow to examine whether the ink-falling occurred. This examination operation was repeated while successively replacing the weight 5 with a heavier one by 50 g within the range of 50 to 300 g.
- the ink-falling was evaluated according to the following criterion:
- the thermal transfer recording medium of the present invention does not cause ink-falling when used in low-temperature environments and exerts excellent dot-reproducibility to give printed images with high-definition and excellent durability.
- a thermal transfer recording medium which causes no ink-falling and is capable of providing printed images with high definition is disclosed which comprises a foundation having thereon a heat-meltable ink layer, and an intermediate adhesive layer provided between the foundation and the heat-meltable ink layer, the intermediate adhesive layer comprising 20 to 80 % by weight of a polyester resin having a glass transition temperature of not higher than 20°C, and 20 to 80 % by weight of at least one of a body pigment and carbon black.
Abstract
A thermal transfer recording medium which
causes no ink-falling and is capable of providing printed
images with high definition is disclosed which comprises
a foundation having thereon a heat-meltable ink layer,
and an intermediate adhesive layer provided between
the foundation and the heat-meltable ink layer, the
intermediate adhesive layer comprising 20 to 80 % by
weight of a polyester resin having a glass transition
temperature of not higher than 20°C, and 20 to 80 % by
weight of at least one of a body pigment and carbon black.
Description
The present invention relates to a thermal
transfer recording medium. More particularly, it relates
to a thermal transfer recording medium which does not
cause the so-called "ink-falling" and is capable of
providing printed images with high definition.
Recently thermal transfer recording system has
been widely applied because thermal transfer printers used
therein have characteristics such as easy maintenance,
availability of small-sized and lightweight ones and low-cost.
In such a thermal transfer recording system,
respective plural heating elements (dots) of a thermal
head are allowed to selectively generate heat in response
to picture signals, thereby selectively transferring the
heat-meltable ink layer of a thermal transfer recording
medium in dots to give a printed image on a receptor.
Therefore, improved dot-reproducibility is required to
obtain printed images with high definition. This dot-reproducibility
refers to the coincidence of the shape of
dots of the transferred heat-meltable ink with that of the
heating elements.
Measures for improving the dot-reproducibility
include selection of a heat-meltable material showing a
sharp peak in its DSC (differential scanning calorimetry)
curve for the vehicle of the heat-meltable ink layer. For
example, carnauba wax (penetration: 1), which is a very
hard wax, was used as a vehicle of the heat-meltable ink
layer, as a result of further consideration given to the
scratch resistance of printed images and the like. A
heat-meltable ink layer containing carnauba wax as a
vehicle thereof offers printed images with improved dot-reproduction
because the wax shows a sharp peak in its DSC
curve. However, the incorporation of a large amount of
carnauba wax into a heat-meltable ink layer results in a
problem that the so-called "ink-falling" phenomenon
occurs. The term "ink-falling" refers to a phenomenon in
which, during traveling of the thermal transfer recording
medium, which is loaded in a cassette, in a thermal
transfer printer, portions of the heat-meltable ink layer
are peeled off from the foundation when the recording
medium comes into sliding contact with guide members of
the cassette, the thermal head, etc. and, hence, is
subjected to external force. The ink-falling phenomenon
is remarkable in using the recording medium in low-temperature
environments.
The ink-falling phenomenon is undesirable
because portions of the recording medium wherein the ink
layer is peeled off cannot be used to form printed images
and the generated ink powder is accumulated in the
thermal head, resulting in a decrease in image quality
or contamination in the inside of the printer.
Conventional measures for preventing the ink-falling
phenomenon include (1) a method wherein the
content of a resin component in the heat-meltable ink
layer is increased to improve adhesion of the ink layer,
and (2) another method wherein a wax having a greater
penetration is used in combination with carnauba wax to
impart flexibility or softness to the heat-meltable ink
layer. However, the method (1) involves a problem that
the viscosity of an ink coating liquid is increased with
increasing content of the resin component and, hence,
the application property of the coating liquid becomes
poor, resulting in failure to form a uniform ink layer.
The method (2) involves a problem that during exchange
of the recording medium in using it in low-temperature
environment, the ink thereof sticks to the hand.
In view of the foregoing, an object of the
present invention is to provide a thermal transfer
recording medium which causes no ink-falling in
low-temperature environments and exerts excellent
dot-reproducibility to form printed images with high
definition.
This and other objects of the present invention
will become apparent from the description hereinafter.
The present invention provides a thermal
transfer recording medium comprising a foundation having
thereon a heat-meltable ink layer, and an intermediate
adhesive layer provided between the foundation and the
heat-meltable ink layer, the intermediate adhesive layer
comprising 20 to 80 % by weight of a polyester resin
having a glass transition temperature of not higher than
20°C, and 20 to 80 % by weight of at least one of a body
pigment and carbon black.
In an embodiment of the present invention, the
polyester resin has a glass transition temperature of not
higher than 0°C.
In another embodiment of the present invention,
the heat-meltable ink layer comprises a coloring agent and
a vehicle, the vehicle comprising not less than 40 % by
weight of caranuba wax.
In still another embodiment of the present
invention, the vehicle comprises not less than 50 % by
weight of carnauba wax.
In a further embodiment of the present
invention, the intermediate adhesive layer comprises
40 to 70 % by weight of a polyester resin having a glass
transition temperature of not higher than 20°C and 30 to
60 % by weight of at least one of a body pigment and
carbon black.
Fig. 1 is a schematic view illustrating a
measuring device for examining the ink-falling of a
thermal transfer recording medium.
The thermal transfer recording medium of the
present invention is characterized in that between the
foundation and the heat-meltable ink layer is provided an
intermediate adhesive layer comprising 20 to 80 % by
weight of a polyester resin having a glass transition
temperature of not higher than 20°C, and 20 to 80 % by
weight of at least one of a body pigment and carbon black.
In the present invention, the intermediate
adhesive layer maintains flexibility or softness even in
low-temperature environments wherein the temperature is
lower than nornmal temperature because a polyester resin
having a glass transition temperature of not higher than
20°C is used as the resin component and, hence, serves as
some type of a buffer layer between the foundation and the
heat-meltable ink layer, thereby causing no ink-falling
even in the case that the heat-meltable ink layer is
relatively hard. The use of a polyester resin having a
glass transition temperature of higher than 20°C as the
resin component for the intermediate adhesive layer
results in ink-falling because the polyester resin
crystallizes in low-temperature environments and the
function of the intermediate adhesive layer as a buffer
layer is lost. From the viewpoint of retaining the
flexibility or softeness of the intermediate adhesive
layer in low-temperature environments, a polyester resin
having a glass transition temperature of not higher than
0°C is preferable.
In the present invention, the intermediate
adhesive layer is incorporated with at least one of a body
pigment and carbon black (hereinafter, in some cases,
referred to as "particulate material") in addtion to the
polyester resin. The incorporation of the particulate
material produces fine unevenness on the surface of the
intermediate adhesive layer to increase the contact area
between the intermediate adhesive layer and the heat-meltable
ink layer. As a result, the ink-falling can be
more sufficiently prevented.
The intermediate adhesive layer in accordance
with the present invention contains 20 to 80 % by weight,
preferably 40 to 70 % by weight, of a polyester resin
having a glass transition temperature of not higher than
20°C, and 20 to 80 % by weight, preferably 30 to 60 % by
weight, of a particulate material. When the content of
the polyester resin having a glass transition temperature
of not higher than 20°C is lower than the above range
or the content of the particulate material is higher
than the above range, the function of the intermediate
adhesive layer as a buffer layer is degraded to fail to
sufficiently exert the effect of preventing the ink-falling
and a problem that the application property of a
coating liquid for the intermediate adhesive layer is
degraded is further invited. When the content of the
polyester resin is higher than the above range or the
content of the particulate material is lower than the
above range, the contact area between the intermediate
adhesive layer and the ink layer is not increased due to
the lower content of the particulate material to fail
to sufficiently exert the effect of preventing the
ink-falling and the so-called "layer-like transfer" which
refers to the phenomenon wherein an excess portion of the
ink layer that is not heated during the thermal transfer
is also transferred, is prone to further occur, resulting
in deterioration of the dot-reproducibility.
As the aforesaid polyester resin there can be
used linear saturated polyester resins which are obtained
by polycondensation of a dibasic acid and a diol compound
and have a glass transition temperature of not higher than
20°C, preferably not higher than 0°C. Examples of the
dibasic acid are adipic acid, azelaic acid, sebacic acid,
phthalic acid and Het acid (chlorendic acid). These
dibasic acids can be used either alone or in combinations
of two or more species thereof. Examples of the
diol compounds are ethylene glycol, propylene glycol,
1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol,
hydrogenated bisphenol A and dibromoneopentylene glycol.
These diol compounds can be used either alone or in
combinations of two or more species thereof.
Examples of body pigments as the particulate
material are silica, calcium carbonate, magnesium
carbonate, barium sulfate and aluminium silicate. These
body pigments can be used either alone or in combinations
of two or more species thereof.
The body pigment and carbon black may be
used either alone or in combiantion as the particulate
material. From the viewpoint of producing fine unevenness
on the surface of the intermediate adhesive layer, the
particulate material preferably has an average particle
size of about 0.5 to about 10 µm.
The intermediate adhesive layer may be
incorporated with a small amount of a dispersing agent or
the like in addition to the aforesaid ingredients.
The thickness of the intermediate adhesive layer
is preferably from 0.3 to 1.0 µm from the viewpoint of the
adhesiveness and the transfer sensitivity.
The intermediate adhesive layer can be formed by
applying onto a foundation a coating liquid which is
prepared by dissolving or dispersing the polyester resin
and the particulate material into an appropriate solvent,
followed by drying.
As the heat-meltable ink layer in accordance
with the present invention there can be used conventional
ones without particular limitation so long as they are
one-time type heat-meltable ink layers each comprising a
coloring agent and a heat-meltable vehicle as main
ingredients. However, preferred is a heat-meltable ink
layer whose vehicle component contains not less than 40 %
by weight, especially not less than 50 % by weight, of
carnauba wax to form printed images having excellent
durability with excellent dot-reproducibility as well as
to prevent the ink-falling in combination with the
aforesaid intermediate adhesive layer. When the content
of carnauba wax in the vehicle component is lower than the
above range, the dot-reproducibility is prone to be
deteriorated to fail to produce printed images with high
definition and the durability of printed images is also
prone to be decreased.
Usable as the vehicle component other than
carnauba wax are waxes other than carnauba wax and/or
resins. As the waxes there can be appropriately selected
and used those conventionally used in this field, such as
paraffin wax, microcrystalline wax, oxidized wax, ester
wax, candelilla wax, rice wax and montan wax. As the
resins there can be appropriately selected and used those
conventionally used in this field, such as polyethylene,
ethylene-vinyl acetate resin, polyamide resins, polyester
resins, epoxy resins and acrylic resins.
Carbon black as well as usual pigments and dyes
can be appropriately selected and used as the coloring
agent.
Suitable ranges for the contents of the
foregoing ingredients in the heat-meltable ink layer in
accordance with the present invention are as follows:
| Ingredient | % by weight |
| Carnauba wax | 40 to 95 (preferably 50 to 90) |
| Other waxs | 0 to 40 (preferably 10 to 30) |
| Resin | 0 to 40 (preferably 10 to 30) |
| Coloring agent | 5 to 20 |
The heat-meltable ink layer in accordance with
the present invention can be formed by applying an ink of
the foregoing formulation onto the aforesaid intermediate
adhesive layer by means of a hot-melt coating method or a
solvent coating method. The thickness of the heat-meltable
ink layer is preferably from 1 to 5 µm from the
viewpoint of the optical density of images and the
transfer sensitivity.
In the present invention, as required, an
overcoat layer may be provided on the heat-meltable ink
layer. The overcoat layer is provided for the purpose of
preventing smearing or the like. Usually the overcoat
layer is an uncolored layer comprising a wax as a main
ingredient.
Usable as the foundation in the present
invention are highly heat-resistant plastic films such
as polyethylene terephthalate film, polycarbonate films,
polyimide films and nylon films, and cellophane, parchment
paper and condenser paper. The thickness of the
foundation is usually from 2 to 10 µm, preferably from 3.5
to 6 µm. From the viewpoint of good adhesion to the
intermediate adhesive layer, polyethylene terephthalate
film is especially preferred.
As required, on the back side (the side adapted
to come into slide contact with a thermal head) of
the foundation may be formed a heat-resistant layer
comprising one or more resins selected from silicone
resins, fluorine-containing resins, acrylic resins, epoxy
resins, phenol resins, cellulose resins, and the like.
The present invention will be more fully
described by way of Examples and Comparative Examples.
It is to be understood that the present invention is
not limited to the Examples, and various changes and
modifications may be made in the invention without
departing from the spirit and scope thereof.
Into a mixed solvent of tolune/methyl ethyl
ketone was added each composition for intermediate
adhesive layer of the formulation shown in Table 1 so that
the total solid concentration became 10 % by weight.
The resulting mixture was agitated at a high speed
in an attritor for 60 minutes to give a coating liquid
for intermediate adhesive layer. Onto one side of a
6 µm-thick polyethylene terephthalate film which was
provided on the other side thereof with a heat-resistant
layer composed of a silicone resin was applied the coating
liquid by means of a solvent coater so that the coating
amount after drying was 0.5 g/m2, followed by drying to
give an intermediate adhesive layer. In Comparative
Example 3, the resulting coating liquid failed to form a
uniform layer due to its poor application property and,
hence, subsequent treatments were not performed.
Each composition for heat-meltable ink layer of
the formulation shown in Table 1 was sufficiently kneaded
by means of a 3-roll mill to give a heat-meltalbe ink.
The ink was applied in a coating amount of 3.0 g/m2 onto
the intermediate adhesive layer by means of a hot-melt
coater to give a heat-meltable ink layer.
Each of the thus obtained thermal transfer
recording media was evaluated for dot-reproducibility and
ink-falling. The results are shown in Table 1.
Each of the thermal transfer recording media
was used to form a printed image under the printing
conditions mentioned below. The printed image was
observed with a metallograph (XF(U)NR made by NIKON
CORPORATION) at a magnification of 50 to determine the
ratio of the area of one dot of the image to that of one
dot of the heating elements (area of one dot of the
image/area of one dot of the heating elements). The
dot-reproducibility was evaluated according to the
following criterion:
- Thermal printer
- : line printer (B-30 made by TEC Corporation
- Thermal head
- : line head type
- Head pressure
- : 700 g/25.4 mm (1 inch)
- Printing energy
- : 19.0 mJ/mm2
- Printing speed
- : 10.2 cm (4 inches)/second
- Receptor paper
- : TPKB (Bekk smoothness: 200 seconds)
- 3
- Area ratio: 0.95 to 1.05
- 2
- Area ratio: 0.90 to less than 0.95
- 1
- Area ratio: less than 0.90
With respect to each of the thermal transfer
recording media, the degree of ink-falling was examined in
a low-temperature environment (dry room at 0°C ) with use
of a measuring device as shown in Fig. 1. This test
is a substitute for a test for examining the degree of
ink-falling when the thermal transfer recording medium is
squeezed through a thermal head.
As shown in Fig. 1, a glass plate 3 was fixed to
a support member 2 which was mounted on a table 1 with
projecting out from an edge of the table 1. A ribbon-like
thermal transfer recording medium 4 (width: 12.7 mm) was
arranged so that it lay upward on the ink layer side and
was brought into contact with the end surface of the glass
plate 3 on the back side thereof. A weight 5 was attached
to one end of the recording medium that hung down and a
movable member 6 was attached to the other end of the
recording medium. In such a state, the movable member 6
was moved at a speed of 1.3 m/minute in the direction
indicated by the arrow to examine whether the ink-falling
occurred. This examination operation was repeated while
successively replacing the weight 5 with a heavier one by
50 g within the range of 50 to 300 g. The ink-falling was
evaluated according to the following criterion:
- 4
- Ink-falling does not occur when a 300-gram weight is used.
- 3
- Ink-falling occurs when a 250-gram weight is used.
- 2
- Ink-falling occurs when a 200-gram weight is used.
- 1
- Ink-falling occurs when a 100-gram weight is used.
| EX.1 | EX.2 | EX.3 | COM. EX.1 | COM. EX.2 | COM. EX.3 | |
| Composition of intermediate adhesive layer (% by weight) | ||||||
| Polyester resin A | 60 | 60 | 90 | 10 | ||
| Polyester resin B | 60 | 60 | ||||
| Polyester resin C | ||||||
| Aluminium silicate | 40 | 40 | 40 | 40 | 10 | 90 |
| Composition of heat-meltable ink-layer (% by weight) | ||||||
| Carnauba wax | 60 | 60 | 40 | 60 | 60 | - |
| Ester wax | 20 | 20 | 40 | 20 | 20 | - |
| Ethylene-vinyl acetate | 10 | 10 | 10 | 10 | 10 | - |
| copolymer | ||||||
| Carbon black | 10 | 10 | 10 | 10 | 10 | - |
| Evaluation | ||||||
| Dot-reproducibility | 3 | 3 | 2 | 2 | 2 | - |
| Ink-falling | 4 | 3 | 4 | 1 | 1 | - |
In addition to the materials and ingredients
used in the Examples, other materials and ingredients can
be used in the Examples as set forth in the specification
to obtain substantially the same results.
As has been described, the thermal transfer
recording medium of the present invention does not cause
ink-falling when used in low-temperature environments and
exerts excellent dot-reproducibility to give printed
images with high-definition and excellent durability.
A thermal transfer recording medium which
causes no ink-falling and is capable of providing printed
images with high definition is disclosed which comprises
a foundation having thereon a heat-meltable ink layer,
and an intermediate adhesive layer provided between
the foundation and the heat-meltable ink layer, the
intermediate adhesive layer comprising 20 to 80 % by
weight of a polyester resin having a glass transition
temperature of not higher than 20°C, and 20 to 80 % by
weight of at least one of a body pigment and carbon black.
Claims (5)
- A thermal transfer recording medium comprising a foundation having thereon a heat-meltable in layer, and an intermediate adhesive layer provided betwee the foundation and the heat-meltable ink layer, the intermediate adhesive layer comprising 20 to 80 % by weight of a polyester resin having a glass transition temperature of not higher than 20°C, and 20 to 80 % by weight of at least one of a body pigment and carbon black
- The thermal transfer recording medium of Claim 1, wherein the polyester resin has a glass transition temperature of not higher than 0°C
- The thermal transfer recording medium of Claim 1, wherein the heat-meltable ink layer comprises a coloring agent and a vehicle, the vehicle comprising not less than 40 % by weight of caranuba wax.
- The thermal transfer recording medium of Claim 3, wherein the vehicle comprises not less than 50 % by weight of carnauba wax.
- The thermal transfer recording medium of Claim 1, wherein the intermediate adhesive layer comprises 40 to 70 % by weight of a polyester resin having a glass transition temperature of not higher than 20°C and 30 to 60 % by weight of at least one of a body pigment and carbon black.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP226785/96 | 1996-08-28 | ||
| JP22678596A JP3825842B2 (en) | 1996-08-28 | 1996-08-28 | One-time type thermal transfer recording medium |
| JP22678596 | 1996-08-28 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0826512A1 true EP0826512A1 (en) | 1998-03-04 |
| EP0826512B1 EP0826512B1 (en) | 2000-03-22 |
Family
ID=16850584
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP19970114863 Expired - Lifetime EP0826512B1 (en) | 1996-08-28 | 1997-08-27 | Thermal transfer recording material heving an intermediate adhesive layer |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0826512B1 (en) |
| JP (1) | JP3825842B2 (en) |
| DE (1) | DE69701496T2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0955181A1 (en) * | 1998-05-08 | 1999-11-10 | Pelikan Produktions Ag | Thermal transfer ribbon with a release layer |
| FR2785566A1 (en) * | 1998-11-11 | 2000-05-12 | Ricoh Kk | IMAGE THERMAL TRANSFER RECORDING MATERIAL |
| US7745065B2 (en) * | 2005-06-02 | 2010-06-29 | Dai Nippon Printing Co., Ltd. | Volume hologram transfer foil, and volume hologram multilayer structure |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001341431A (en) | 2000-05-31 | 2001-12-11 | Fujicopian Co Ltd | Heat sensitive transfer recording medium |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60212393A (en) * | 1984-04-06 | 1985-10-24 | Fujitsu Ltd | Ink sheet for thermal transfer recording |
| JPS61169283A (en) * | 1985-01-22 | 1986-07-30 | Fujitsu Ltd | Thermal transfer ink ribbon |
| EP0363929A2 (en) * | 1988-10-11 | 1990-04-18 | Fujitsu Limited | Thermal imprint ink sheet |
| JPH02141286A (en) * | 1988-11-24 | 1990-05-30 | Fujitsu Ltd | Thermal transfer ink sheet |
| EP0410724A2 (en) * | 1989-07-26 | 1991-01-30 | Konica Corporation | Heat-transfer image recording medium |
-
1996
- 1996-08-28 JP JP22678596A patent/JP3825842B2/en not_active Expired - Fee Related
-
1997
- 1997-08-27 DE DE1997601496 patent/DE69701496T2/en not_active Expired - Fee Related
- 1997-08-27 EP EP19970114863 patent/EP0826512B1/en not_active Expired - Lifetime
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60212393A (en) * | 1984-04-06 | 1985-10-24 | Fujitsu Ltd | Ink sheet for thermal transfer recording |
| JPS61169283A (en) * | 1985-01-22 | 1986-07-30 | Fujitsu Ltd | Thermal transfer ink ribbon |
| EP0363929A2 (en) * | 1988-10-11 | 1990-04-18 | Fujitsu Limited | Thermal imprint ink sheet |
| JPH02141286A (en) * | 1988-11-24 | 1990-05-30 | Fujitsu Ltd | Thermal transfer ink sheet |
| EP0410724A2 (en) * | 1989-07-26 | 1991-01-30 | Konica Corporation | Heat-transfer image recording medium |
Non-Patent Citations (3)
| Title |
|---|
| PATENT ABSTRACTS OF JAPAN vol. 10, no. 378 (M - 546) 17 December 1986 (1986-12-17) * |
| PATENT ABSTRACTS OF JAPAN vol. 10, no. 66 (M - 461) 15 March 1986 (1986-03-15) * |
| PATENT ABSTRACTS OF JAPAN vol. 14, no. 379 (M - 1012) 16 August 1990 (1990-08-16) * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0955181A1 (en) * | 1998-05-08 | 1999-11-10 | Pelikan Produktions Ag | Thermal transfer ribbon with a release layer |
| FR2785566A1 (en) * | 1998-11-11 | 2000-05-12 | Ricoh Kk | IMAGE THERMAL TRANSFER RECORDING MATERIAL |
| US7745065B2 (en) * | 2005-06-02 | 2010-06-29 | Dai Nippon Printing Co., Ltd. | Volume hologram transfer foil, and volume hologram multilayer structure |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0826512B1 (en) | 2000-03-22 |
| JPH1067184A (en) | 1998-03-10 |
| JP3825842B2 (en) | 2006-09-27 |
| DE69701496D1 (en) | 2000-04-27 |
| DE69701496T2 (en) | 2000-08-24 |
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