JPH10278328A - Thermal head - Google Patents

Abstract

(57) [Problem] To provide a thermal head capable of linearly configuring a transport path of printing paper in a high-speed printing color printer. A stainless steel plate of a thermal head with a preheating function is mounted on a surface of a heat sink by screws. Reference numeral 12Y denotes a control IC, which controls a heating resistor (not shown) to generate Joule heat necessary for printing. The stainless steel plate 52 has a curved heat sink 51.
It is fixed with a screw 90 by a long screw hole in the stainless steel plate 52 so as to crawl. Therefore, the deformation of the stainless steel plate 52 caused by the difference in linear thermal expansion coefficient between the heat sink 51 and the stainless steel plate 52 is prevented by the sliding operation of the stainless steel plate 52 on the heat sink 51 by the long screw holes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermal head suitable for use in a thermal printer.

[0002]

2. Description of the Related Art FIG. 10 is a side view showing a schematic structure of a conventional color printer. In this figure, reference numeral 1 denotes a storage case for storing a roll-shaped color thermal paper 2, which is configured to block external light and maintain the inside at a constant humidity. The color thermal paper 2 is wound around a delivery reel 3 and is fed in a direction indicated by an arrow Z in FIG.

The color thermal paper 2 comprises a base material, and a yellow recording layer, a magenta recording layer, a cyan recording layer,
And each layer formed in the order of the heat-resistant protective layer. The yellow recording layer develops a yellow color by a chemical reaction when energy equal to or higher than a certain heat energy (hereinafter, referred to as yellow color development start energy) is applied. Further, the magenta recording layer develops a magenta color by a chemical reaction when energy equal to or higher than a certain heat energy (hereinafter, referred to as magenta coloring start energy) is applied. Further, the cyan recording layer develops a cyan color by applying energy equal to or higher than a predetermined thermal energy (hereinafter, referred to as cyan coloring start energy). The yellow color start energy, the magenta color start energy, and the cyan color start energy described above are the yellow color start energy TBY <the magenta color start energy TBM <
It has a relationship of cyan color start energy TBC.

In FIG. 10, reference numerals 9 and 9 denote feed rollers disposed in the vicinity of the paper feed port 1a, respectively, so that their outer peripheral surfaces are in contact with each other. It serves to transport in the direction of arrow Z shown in the figure.
Reference numeral 10 denotes a platen roller disposed to the right of the feed rollers 9 and 9. Reference numeral 11Y denotes a yellow thermal head disposed above the platen roller 10, and is used when printing yellow. The yellow thermal head 11 </ b> Y controls a plurality of heating resistors (not shown) arranged at a fixed interval corresponding to a plurality of dots and a data signal to be supplied to the plurality of heating resistors. And a control IC (Integrated Circuit) 12Y.

In FIG. 10, reference numerals 20 and 20 denote guide rollers disposed on the right side of the platen roller 10 and at a position lower than the position of the platen roller 10, respectively. They are provided so as to be in contact with each other.
That is, the guide rollers 20, 20 are connected to the color thermal paper 2
And serves to bend the transfer path of the color thermal paper 2 to the lower right of the platen roller 10 so that the color thermal paper 2 does not contact the control IC 12Y. 21Y is the guide rollers 20, 20
Is the yellow fixing lamp located at the upper right of
The above-mentioned light having a peak wavelength of 0 nm is transferred to the color thermal paper 2
Irradiate the surface of This yellow fixing lamp 21Y is
It serves to fix the yellow color in the yellow recording layer of the color thermal paper 2 described above.

Reference numerals 22 and 22 denote yellow fixing lamps 21Y.
The guide rollers are disposed at the lower right side of the table and at the same height as the height of the guide rollers 20, 20, and are provided so that their outer peripheral surfaces are in contact with each other.
These guide rollers 22, 22 serve to guide the color thermal paper 2 while sandwiching it. 23 is the right side of the guide rollers 22 and 22 and the platen roller 10
Is a platen roller disposed at a position which is the same height as the height of the platen. Reference numeral 11M denotes a magenta thermal head disposed above the platen roller 23, and is used for printing magenta color. This magenta thermal head 1
1M has the same configuration as the yellow thermal head 11Y, and has a control IC 12M.

[0007] Reference numerals 24, 24 denote guide rollers disposed on the right side of the platen roller 23, respectively, such that their outer peripheral surfaces come into contact with each other. These guide rollers 24 guide the color thermal paper 2 while sandwiching them, and the color thermal paper 2 is controlled by the control IC 12M.
And serves to bend the transport path of the color thermal paper 2 to the lower right from the platen roller 23 so as not to contact with the paper. 2
Reference numeral 1M denotes a magenta color fixing lamp disposed on the upper right of the guide rollers 24, 24, and irradiates light having a peak wavelength of 365 nm to the surface of the color thermal paper 2. That is, the magenta fixing lamp 21M serves to fix the magenta color on the magenta recording layer of the color thermal paper 2 described above.

Reference numerals 25 and 25 shown in FIG. 10 denote lower right of the magenta fixing lamp 21M and guide rollers 2
The guide rollers are arranged at the same height as the heights 4 and 24, and are provided so that their outer peripheral surfaces come into contact with each other. The guide rollers 25 serve to guide the color thermal paper 2 while sandwiching it. 26 is
The platen roller is disposed on the right side of the guide rollers 25, 25 and at the same height as the platen roller 23. Reference numeral 11C denotes a cyan thermal head disposed above the platen roller 26, and is used for cyan printing. This thermal head 1 for cyan
1C has the same configuration as the above-described yellow thermal head 11Y, and has a control IC 12C.

Reference numerals 27, 27 denote guide rollers disposed at the lower right of the platen roller 26 and at the same height as the height of the guide rollers 24, 24, respectively.
Each outer peripheral surface is provided so as to abut. These guide rollers 27 guide the color thermal paper 2 while sandwiching the same.
It serves to bend the transport path of the color thermal paper 2 to the lower right from the platen roller 26 so as not to come into contact with C and 12C. Reference numeral 21C denotes a bleaching lamp disposed above and to the right of the guide rollers 27, and irradiates light of a predetermined wavelength to the surface of the color thermal paper 2. This bleaching lamp 21C
Functions to bleach the non-colored portion of the color thermal paper 2.

Reference numerals 28, 28 denote feed rollers provided on the lower right side of the bleaching lamp 21C, respectively, such that their outer peripheral surfaces are in contact with each other. Reference numeral 29 denotes a cutter disposed to the right of the feed rollers 28, 28, which cuts the end of the color thermal paper 2 into a predetermined length. Reference numeral 30 denotes a storage case disposed on the right side of the cutter 29,
9 are stacked and stored.

Next, the operation of the above-described conventional color printer will be described. In FIG. 10, when power is supplied to each unit of the apparatus, the feed rollers 9, 9 and the like are driven,
The color thermal paper 2 is transported in the direction of arrow Z shown in FIG.
When the leading end of the color thermal paper 2 is located immediately below the yellow thermal head 11Y, the yellow thermal head 11Y is moved via the color thermal paper 2 to the platen roller 1Y.
Press against 0.

Next, when print data is input to the control IC 12Y, the control IC 12Y applies a pulse voltage having a fixed pulse width to the plurality of heating resistors. As a result, Joule heat is generated in the plurality of heating resistors, and as a result, the energy of one line portion of the color thermal paper 2 increases. Then, when the energy of one line portion of the color thermal paper 2 is equal to or more than the above-described yellow coloring start energy, a yellow color is generated in the yellow recording layer of the color thermal paper 2. Hereinafter, the printing of the yellow color described above proceeds, and accordingly, the color thermal paper 2 is conveyed line by line.

Then, the yellow printing described above proceeds, and the end of the color thermal paper 2 is moved to the yellow fixing lamp 21Y.
Is located just below the yellow color fixing lamp 21Y, the light generated by the yellow color fixing lamp 21Y hits the yellow color portion of the color thermal paper 2, and the yellow color is fixed.

When the end of the color thermal paper 2 is located immediately below the magenta thermal head 11M, the operation is similar to that of the yellow thermal head 11Y described above.
A pulse voltage is applied to the plurality of heating resistors of the magenta thermal head 11M from the control IC 12M. As a result, Joule heat is generated in the plurality of heating resistors, and as a result, the energy of one line portion of the color thermal paper 2 increases.

When the energy of one line portion of the color thermal paper 2 becomes equal to or greater than the above-described magenta color development start energy, a color magenta is generated on the magenta recording layer of the color thermal paper 2. When the printing of the above-described magenta color proceeds and the end of the color thermal paper 2 is located immediately below the magenta fixing lamp 21M, the magenta fixing lamp 2
The light generated by 1M hits the magenta portion of the color thermal paper 2 and the magenta color is fixed.

When the end of the color thermal paper 2 is located immediately below the thermal head 11C for cyan, a plurality of heating elements of the thermal head 11C for cyan are operated in the same manner as the operation of the yellow thermal head 11Y. In
A pulse voltage is applied from the control IC 12C. As a result, Joule heat is generated in the plurality of heating resistors, and as a result, the energy of one line portion of the color thermal paper 2 increases.

When the energy of one line portion of the color thermosensitive paper 2 is equal to or higher than the above-described cyan color development start energy, a cyan color is generated in the cyan recording layer of the color thermosensitive paper 2. Then, the printing of cyan described above proceeds,
When the end portion of the color thermal paper 2 is located directly below the bleaching lamp 21C, the light hits the cyan color portion of the color thermal paper 2 and the cyan color is fixed.

[0018]

By the way, in the above-described thermal head with a preheating function and a double-line thermal head (Japanese Patent Application No. 8-313966, the applicant of which filed the application earlier), the IC12Y,
In order to prevent the color thermal paper 2 from coming into contact with the ICs 12M and 12C, a guide roller is used to complicately bend the transport path of the color thermal paper 2. For this reason, there has been a problem that the mechanism of the color printer is complicated and the size of the printer is increased. In addition, since the transport path of the printing paper is bent in a complicated manner, it is not possible to accurately position the color thermal paper 2 in each thermal head, and there is a disadvantage that a displacement of a printed portion occurs.

In order to solve the above-mentioned drawback, a method of devising the shape of the substrate of the thermal heads 11Y, 12M and 12C is conceivable. However, there is a problem that the thermal head substrate is deformed due to the difference in the thermal expansion coefficient. The present invention has been made under such a background, and an object of the present invention is to provide a thermal head capable of linearly configuring a printing paper transport path in a high-speed printing color printer.

[0020]

According to the first aspect of the present invention,
In the thermal head, a heat sink having a curved surface and a screw hole formed in the surface, a substrate having a hole with a diameter larger than the screw hole, a heating resistor formed on the surface of the substrate, And a screw that penetrates the hole and is screwed into the screw hole to attach the substrate along the upper surface of the heat sink.

According to a second aspect of the present invention, in the thermal head of the first aspect, a heat sink having a curved upper surface and a screw hole formed on the surface, and a substrate having a hole having a diameter larger than the screw hole is formed. A long electrode protrudingly formed on the surface of the substrate, a heating resistor formed on the surface of the substrate, and passing through the hole and being screwed into the screw hole to place the substrate on the heat sink. Along with a screw which is slidably attached to the electrode portion in a direction parallel to the electrode portion.

According to a third aspect of the present invention, in the thermal head according to the first or second aspect, the hole is formed as an ellipse having a longer diameter in a direction parallel to the electrode portion. Features. According to a fourth aspect of the present invention, in the thermal head according to any one of the first to third aspects, an output terminal thereof is connected to one end of the heating resistor, and the one end of the heating resistor includes: Control means for applying a pulse voltage having a pulse width corresponding to print data between the heating resistor and the other end of the heating resistor which is grounded.

According to a fifth aspect of the present invention, in the thermal head according to any one of the first to fourth aspects, the substrate is formed of a stainless steel material. According to a sixth aspect of the present invention, in the thermal head according to the first to sixth aspects, the thickness of the substrate is more than 0 and 1 mm or less. According to a seventh aspect of the present invention, in the thermal head according to any one of the first to sixth aspects, the width of the common electrode portion is more than 0 and 2 mm or less. The invention according to claim 8 is the thermal head according to claim 1 or 7, wherein the first insulator and the second insulator are both formed of a glass material.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a color printer using a thermal head according to an embodiment of the present invention. In this figure, reference numeral 2 denotes a color thermal paper, which is wound around a feed reel 3 and is fed in the direction of arrow Z shown in FIG.

Here, the above-described color thermal paper 2 has a cyan recording layer, a magenta recording layer, a yellow recording layer, and a heat-resistant protective layer formed in this order on the surface of the base material. The cyan recording layer is composed of a cyan developer, cyan microcapsules, and a cyan leuco dye. A large number of cyan microcapsules each containing a cyan leuco dye are arranged in the cyan developer. The cyan developer has a chemical property of emitting cyan by a chemical reaction with a cyan leuco dye.

The above-mentioned cyan microcapsules are softened when energy equal to or higher than a predetermined heat energy (hereinafter, referred to as cyan coloring start energy) is applied, and an external cyan color developing material is transmitted to an internal cyan leuco dye side. It has the physical property of: The transmittance of the cyan leuco dye increases in proportion to the applied energy.

The above-described magenta recording layer is composed of a magenta coupler, a magenta microcapsule and a magenta diazo dye. A large number of magenta microcapsules each containing a magenta diazo dye are arranged in the magenta coupler. This magenta coupler has a chemical property of emitting a magenta color by a chemical reaction with a magenta diazo dye. Further, the magenta diazo dye has a chemical property that when it receives light having a peak wavelength of 365 nm, it is decomposed so as not to emit a magenta color.

The above-mentioned magenta microcapsules are softened when energy equal to or higher than a predetermined heat energy (hereinafter, referred to as magenta coloring start energy) is applied, so that an external magenta coupler is transmitted to an internal magenta diazo dye. Has physical properties. The transmittance of the magenta coupler increases in proportion to the applied energy.

Further, the above-mentioned yellow recording layer is composed of yellow couplers, yellow microcapsules and yellow diazo dyes. A large number of yellow microcapsules each containing an yellow diazo dye are arranged in the yellow coupler. The yellow coupler has a chemical property of emitting a yellow color by a chemical reaction with the yellow diazo dye. Further, the yellow diazo dye also has a chemical property that, when it receives light having a peak wavelength of 420 nm, it is decomposed to stop emitting yellow color.

The above-mentioned yellow microcapsules are softened when an energy equal to or higher than a certain heat energy (hereinafter referred to as yellow coloring start energy) is applied, so that an external yellow coupler is transmitted to the inside yellow diazo dye side. Has properties. The transmittance of this yellow coupler is
It increases in proportion to the energy applied.

Here, for example, in the above-described relationship between the yellow coloring start energy, the cyan coloring start energy, and the yellow coloring start energy, and the relationship between the yellow coloring start energy and the like and the color density of yellow and the like, the yellow coloring start energy is determined. The energy etc. is the yellow color start energy TBY <
There is a relationship of magenta coloring start energy TBM <cyan coloring start energy TBC. (In the present description, the coloring energy has the above relationship, but the intensity of the coloring energy differs depending on the material used. Therefore, the coloring order is changed according to the coloring energy of the material. Therefore, the printing process is changed in accordance with the coloring energy.)

That is, among the yellow microcapsules, the magenta microcapsules and the cyan microcapsules, the yellow microcapsules begin to soften with the lowest energy (yellow coloring start energy TBY), and the cyan microcapsules have the highest energy (cyan coloring start energy). It starts to soften due to energy TBC). In addition, the magenta microcapsules have a yellow coloring start energy TBY.
, And begins to soften at an intermediate energy (magenta coloring start energy TBM) between cyan and cyan coloring start energy TBC.

The relationship between the energy in the yellow recording layer and the color density of yellow is that the color density of yellow is
Yellow coloring start energy TBY + yellow gradation energy TGY
In response to the increase in darkness, the darker gray energy TGY
Is changed by changing.

The relationship between the energy in the magenta recording layer and the color density of the magenta color is such that the color density of the magenta color becomes darker in accordance with the increase of the magenta color start energy TBM + the magenta gradation energy TGM, and the magenta gradation It changes by changing the energy TGM.

Further, the relationship between the energy in the cyan recording layer and the color density of cyan is such that the color density of cyan becomes darker in response to the increase of the cyan color start energy TBC + cyan tone energy TGC, and the cyan tone is increased. Energy T
It changes by changing the GC. Further, the heat-resistant protective layer is formed on the surface of the yellow recording layer, and serves to protect the surface of the yellow recording layer.

In FIG. 1, reference numerals 9 and 9 denote feed rollers disposed in the vicinity of a paper feed roll, respectively, such that their outer peripheral surfaces are in contact with each other. And has the role of transporting in the direction of arrow Z. 1
Reference numeral 0 denotes a platen roller disposed to the right of the feed rollers 9 and 9. Reference numeral 11YN denotes a yellow thermal head disposed above the platen roller 10, and is used when printing yellow. 12Y, 12M and 12C
Is an integrated circuit (IC), which controls a heating resistor on each thermal head.

The yellow thermal head 11
The detailed configuration of YN will be described. FIG. 2 is a perspective view in a state where the yellow thermal head 11YN is turned upside down. In this figure, 51 is a heat sink for heat dissipation. Reference numeral 52 denotes a stainless steel plate-like substrate of a thermal head having a preheating function, which is fixed to the surface of the heat sink 51 by screws 90.

Next, the thermal head substrate will be described in detail. FIG. 3 is a plan view of a thermal head substrate constituting the yellow thermal head 11YN. In this figure, reference numeral 52 denotes a thermal head substrate made of stainless steel. Reference numerals 54, 54,... Denote heating resistors for gradation, which are formed in a long shape at regular intervals on the surface of the grace raised portion. These gradation heating resistors 54, 5
4,... Are provided corresponding to one dot at the time of printing, and heat generated according to the pulse width of the supplied pulse voltage for gradation control is transferred to a color thermal paper 2 (not shown).
(See FIG. 1).

Reference numerals 55, 55,... Denote a plurality of heating resistors for preheating, each of which is formed in a long shape at regular intervals on the surface of the raised portion of the grace. Are respectively provided corresponding to one dot at the time of printing, and the heat generated according to the pulse width of the supplied preheating pulse voltage is not shown. Each is applied to color thermal paper 2 (see FIG. 1).

Reference numeral 56 denotes a common electrode portion formed on the surface of the stainless steel plate 52. The common electrode 56 includes printing heating resistors 54, 54,... And preheating heating resistors 55, 55,. .. one end of which is electrically common electrode 57
Are connected to each other. Are provided on the surface of the stainless steel plate 52 as heating elements for gradation 54, 54,
Are respectively formed corresponding to the plurality of individual lead electrodes 58, 58,..., And one end is electrically connected to the other end of the printing heating resistors 54, 54,. Are connected to each other. Reference numerals 59 are lead electrodes formed on the surface of the stainless steel plate 52 corresponding to the heating resistors 55, 55,... For preheating, respectively, and are electrically connected to the emitter terminal of the power transistor 60 in common. I have.

Each of the other ends of the individual lead electrodes 58, 58,... Has a lead pad 61. Reference numeral 62 denotes a lead pad, which is connected to each terminal of the control IC 12Y. The terminals of the control IC and the other ends of the gradation heating resistors 54, 54,...
1, electrically connected via a lead wire 63 and a lead pad 62.

Further, the control IC 12Y is
A pulse voltage is applied to the heating resistors 54, 54,... Based on the print data of yellow printing supplied from the flexible wiring board via the connection terminal pattern 64 and the lead pad 65 from a control unit (not shown). Is supplied.

Next, the heating resistor portion of the thermal head substrate will be described with reference to FIG. FIG. 4 is a cross-sectional view taken along line AA ′ of the thermal head substrate of FIG. In this figure, 52 is a stainless steel plate. 53a and 53b
Is a grace formed by swelling on the surface of the stainless steel plate 52, and its cross section has a semi-spindle shape. The graces 53a and 53b serve as heat storage materials. 53c is a flat grace. 54 is
The heating resistor for gradation is formed on the grace 53a.

Reference numeral 55 denotes a heating resistor for preheating,
It is formed on the grace 53b. One end of each of the gradation heating resistor 54 and the preheating heating resistor 55 is electrically connected to a common electrode portion 56 and a common electrode 57. The other end of the gradation heating resistor 54 is electrically connected to the individual lead electrode 58. The other end of the heating resistor 55 for preheating is electrically connected to the lead electrode 59. Reference numeral 92 denotes a resistor layer that forms the gradation heating resistor 54 and the preheating heating resistor 55. Reference numeral 93 denotes a protective film for protecting the gradation heating resistor 54 and the preheating heating resistor 55. 94
Is a back surface grace glass.

Here, the thickness of the stainless steel plate 52 is “1”.
mm or less ". The stainless steel plate 52
Is preferably formed at "0.5 mm or less", and more preferably at "0.3 mm or less" if possible. further,
The width of the common electrode section 56 is set to “2 mm or less”. The width of the common electrode portion 56 is preferably “500
μm or less ”and, if possible,“ 100 μm or less ”.

Next, attachment of the thermal head substrate shown in FIG. 3 to a heat sink will be described with reference to FIG. FIG. 5 is a conceptual diagram of a thermal head showing how to attach a thermal head substrate to a curved heat sink. In this figure, 12Y is the control I
C. 51 is a curved heat sink. The stainless plate 52 is fixed by an oval hole 91 by screws 90 so as to follow the curved heat sink. Reference numeral 95 denotes a flexible wiring board, and a signal for controlling the control IC 12Y is sent from a printer control unit (not shown).

A screw fixing portion for fixing the stainless steel plate 52 to the heat sink 51 will be described with reference to FIG.
FIG. 6 is a sectional view taken along line BB ′ of the thermal head of FIG. The stainless steel plate 52 is fixed to the heat sink 51 by tightening the screw 90 to the threaded heat sink 51 through the hole 91 of the stainless steel plate 52. Reference numeral 96 denotes a spacer, which is provided in the hole 91 of the stainless steel plate 52.

The screw 90 is fastened to the screw hole of the heat sink 51 via the spacer 96. 97 is a washer,
The stainless plate 52 is pressed so as not to come off the heat sink 51. 98 is a spring washer,
The screw 90 is fixed so as not to be loosened.

Here, the length of the spacer 96 is slightly longer than the thickness of the stainless steel plate 52, for example, 〜100.
Use a spacer that is about μ long. For this reason, the stainless steel plate 52 is not completely fixed to the heat sink 51 by the screws 90. The stainless plate 52 is pressed against the heat sink 51 by the washer 97. That is, the tightening and tightening of the screw 90 causes the stainless steel plate 52
The upper limit of the force that presses the heat sink 51 onto the heat sink 51 is adjusted.

Since the hole 91 has an elliptical shape, if both dimensions are different from the initial state due to the bimetal effect due to the difference in linear expansion coefficient between the stainless steel plate 52 and the heat sink, the screw is fixed. The stainless steel plate 52 slides on the heat sink 51 with 90 as a reference position.
Therefore, the stainless steel plate 52 slides on the heat sink 51 during operation, so that the stress due to the stress applied to the stainless steel plate 52 is reduced.

Next, referring to FIG.
Reference numeral 9 serves to guide the color thermal paper 2 while sandwiching it. Reference numeral 21Y denotes a yellow fixing lamp disposed above the surface of the color thermal paper 2 and irradiates the light having a peak wavelength of 420 nm to the surface of the color thermal paper 2. That is, the yellow fixing lamp 21Y serves to fix yellow in the yellow recording layer.

Reference numeral 11MN downstream of the yellow fixing lamp 21Y shown in FIG. 1 is a magenta thermal head disposed above the platen roller 23, and is used for printing magenta. This thermal head 11 for magenta
The structure of the MN is the same as that of the yellow thermal head 11Y described above.
N (see FIG. 2, FIG. 3, or FIG. 4).

Reference numeral 21M downstream of the magenta thermal head 11MN is a magenta fixing lamp disposed above the surface of the color thermal paper 2, and the above-mentioned light having a peak wavelength of 365 nm is applied to the surface of the color thermal paper 2. Irradiation. That is, the magenta fixing lamp 21M serves to fix the magenta color on the magenta recording layer.

Reference numeral 26 shown in FIG. 1 is a platen roller disposed downstream of the magenta fixing lamp 21M. 11
CN is a thermal head for cyan disposed above the platen roller 26, and is used at the time of cyan printing. The configuration of the cyan thermal head 11CN is the same as the configuration of the yellow thermal head 11YN described above (see FIG. 2, FIG. 3, or FIG. 4).

21C is a thermal head 11C for cyan.
This is a bleaching lamp disposed downstream of N and irradiates light of a predetermined wavelength to the surface of the color thermal paper 2. The bleaching lamp 21C has a function of bleaching a non-colored portion of the color thermal paper 2.

Reference numerals 28, 28 denote feed rollers provided at the lower right of the bleaching lamp 21CN, respectively, such that their outer peripheral surfaces are in contact with each other. Reference numeral 29 denotes a cutter disposed to the right of the feed rollers 28, 28, which cuts the end of the color thermal paper 2 into a predetermined length. Reference numeral 30 denotes a storage case disposed on the right side of the cutter 29, in which the color thermal papers 2a, 2a,... Cut by the cutter 29 are stacked and stored.

Next, the operation of the above-described first conventional color printer will be described with reference to FIGS. First, in FIG. 1, when power is supplied to each unit of the apparatus, the feed rollers 9, 9 are driven to rotate by a motor (not shown). As a result, the color thermal paper 2 is conveyed in the direction of arrow Z shown in FIG. Then, when the end of the color thermal paper 2 is positioned on the platen roller 10, the feed rollers 9 are stopped, and the yellow thermal head 11 </ b> YN is pressed against the platen roller 10 via the color thermal paper 2. That is, the end portion of the color thermal paper 2 is in pressure contact with the heating resistors 55, 55,... For preheating of the yellow thermal head 11YN shown in FIG. 3 and the platen roller 10 shown in FIG. It is in.

Then, the IC 12Y reads the print data of the first line related to the yellow color at the timing of the clock signal for printing one line, and then latches the print data in the latch circuit (not shown) at the timing of the latch signal. The print data is data corresponding to each dot in one line.

Now, a preheating operation is performed in which the energy immediately before softening is applied to the yellow microcapsules of the yellow recording layer. That is, the preheating operation refers to an operation of applying the energy immediately before the yellow coloring start energy TBY to the yellow microcapsules, in other words, an operation of bringing the yellow microcapsules into a state immediately before the external yellow coupler is transmitted to the inside.

That is, for example, a “high” switching control signal is input to the base terminal of the NPN-type power transistor 60. As a result, the power transistor 60 is turned on, and the preheating heating resistors 55, 5
, A preheating pulse voltage is applied.
As a result, Joule heat is generated in the preheating heating elements 55, 55,..., So that the energy of the yellow microcapsules in the yellow recording layer increases with time.

Then, the switching control signal is "low".
It is said. As a result, the power transistor 60 is turned off, and the preheating pulse voltage supplied to the preheating heating resistors 55, 55,... Becomes zero. That is, a preheating pulse voltage having a pulse width PBY is applied to the preheating heating resistors 55, 55,..., And the yellow microcapsules of the yellow recording layer are supplied with yellow coloring start energy TBY during this time. Immediate energy is applied.

The platen roller 10 shown in FIG.
The color thermosensitive paper 2 is driven to rotate by an angle corresponding to one line, and is conveyed by one line in the arrow Z direction shown in FIG. As a result, the one-line portion of the color thermal paper 2, that is, the portion to which the energy immediately before the cyan coloring start energy TBC is applied is the printing heating resistor 54 shown in FIG.
54,... At the same time, the two-line portion of the color thermal paper 2 is located immediately adjacent to the preheating heating resistors 55, 55,.

Further, the IC 12Y receives the clock signal.
After reading the print data of the second line relating to the yellow color at the timing, the print data of the second line is latched by the latch circuit at the timing of the latch signal.

When the strobe signal is input to the IC 12Y, the IC 12Y generates the print heating resistors 54, 54,... Based on the print data latched in the latch circuit at the timing of the strobe signal. Control is performed to apply a gradation pulse voltage to.

For example, assuming that the print data is data for instructing printing of a 180-gray yellow color, the IC 12Y includes the gray-scale heating resistors 54, 54,
.. Perform a switching operation in which the gradation heating resistor and a DC power supply (not shown) are conducted. Thus, the gradation heating resistors 54, 54,.
Are applied with a gradation pulse voltage, and the heating pulse resistors 54, 54,... Generate Joule heat by the gradation pulse voltage.

Then, the energy of the yellow microcapsules in the yellow recording layer gradually rises above the yellow coloring start energy TBY by the Joule heat. As a result, the yellow microcapsules begin to soften, and an external yellow coupler passes through the yellow microcapsules.

Further, a chemical reaction occurs between the yellow diazo dye and the yellow coupler, and a yellow color is generated on the color thermal paper 2. Then, as the energy of the yellow microcapsules increases with the passage of time, the above-described chemical reaction proceeds, and as a result, the gradation of the yellow color increases.

In parallel with the above-described yellow printing operation on the first line, a preheating operation is performed on the two lines of the color thermal paper 2. That is, when a high-level switching control signal is input to the base terminal of the power transistor 60, the power transistor 60 is turned on, and the heating resistor 5 for preheating is turned on.
, 55,... Generate Joule heat. This allows
Similarly to the above-described operation, the energy of the yellow microcapsules in the yellow recording layer increases with time.

The IC is a heating resistor 5 for printing.
The gradation pulse voltages supplied to 4, 54,... Are set to zero. As a result, the energy increase of the yellow microcapsules in the yellow recording layer stops, and the chemical reaction between the yellow microcapsules and the yellow coupler stops. That is,
The heating resistors 54, 54,... For printing have a pulse width PGY.
Is applied. In other words, the energy of the yellow microcapsules in the yellow recording layer is set to a value of yellow coloring start energy TBY + yellow gradation energy TGY corresponding to the pulse width PGY. Therefore,
At this point, a yellow color of 180 gradations has been generated in the yellow recording layer.

At the same time as the above operation, the switching control signal is set to "low", whereby the power transistor 60 is turned off. As a result, the preheating pulse voltage applied to the preheating heating resistors 55, 55,... Is made zero, and the two-line portion of the color thermal paper 2 is set to the energy immediately before the yellow coloring start energy TBY. . Further, in the same manner as the operation described above, IC1
2Y latches the print data of the third line for the yellow color in the latch circuit.

In addition, the platen roller 10 shown in FIG. 1 is driven to rotate by an angle corresponding to one line. As a result, the above-described two-line portion of the color thermal paper 2 is located immediately adjacent to the heating resistors for printing 54, 54,... Are located immediately adjacent to the resistors 55, 55,.

Then, similarly to the above-described operation, the IC 12Y includes the heating resistors for printing 54, 54,.
, A gradation pulse voltage is applied. This allows
The energy of the two-line portion of the color thermal paper 2, which is the energy immediately before the yellow color formation start energy TBY, increases, and a yellow color is generated in the yellow recording layer by a chemical reaction.

That is, a gradation pulse voltage having a pulse width PGY is applied to the printing heating resistors 54, 54,... Shown in FIG. In other words, the energy of the yellow microcapsules in the yellow recording layer is set to a value of yellow coloring start energy TBY + yellow gradation energy TGY corresponding to the pulse width PGY.

As a result, in the yellow recording layer, a yellow color of 64 tones corresponding to the pulse width PGY is generated. Less than,
By repeating the above-described operation, the yellow printing operation for the third line and the subsequent portions of the color thermal paper 2 and the preheating operation for the fourth and the subsequent portions of the color thermal paper 2 are performed.

Then, when the above-described yellow printing proceeds and the end of the color thermal paper 2 shown in FIG. 1, that is, the portion where the yellow color is generated, is conveyed to just below the yellow fixing lamp 21Y. Then, yellow fixing is performed in the same manner as the above-described operation.

When the end of the color thermal paper 2 is pressed between the magenta thermal head 11MN and the platen roller 23, the yellow thermal head 11
The magenta printing operation is performed in the same manner as the yellow printing operation in YN. That is, in the magenta printing operation, after performing a preheating operation on one line portion of the color thermal paper 2, an operation of actually printing magenta color on the one line portion is performed, and two lines are printed. The preheating operation is performed on the portions in parallel.

That is, during the preheating operation,
A preheating pulse voltage having a pulse width PBM (> pulse width PBY) corresponding to the magenta coloring start energy TBM is simultaneously applied to the preheating heating resistors 55, 55,.... Thus, the energy immediately before the magenta coloring start energy TBM is applied to the magenta microcapsules of the magenta recording layer.

On the other hand, in the operation for actually printing the magenta color described above, the gradation pulse voltage of the pulse width PGM corresponding to the gradation designated by the print data is set to the level shown in FIG.
Are applied to the printing heating resistors 54, 54,... Shown in FIG. As a result, the magenta microcapsules in the magenta recording layer are provided with energy having a value of magenta coloring start energy TBM + magenta gradation energy TGM.

As a result, the magenta coupler transmits through the magenta microcapsules. As a result, a magenta coupler and a magenta diazo dye cause a chemical reaction in the magenta recording layer, and a magenta color is generated. And FIG.
When the end portion of the color thermal paper 2 shown in FIG. 3, that is, the portion where the magenta color is generated is located immediately below the magenta fixing lamp 21M, the magenta color is fixed on the magenta recording layer.

Then, the printing of the yellow and magenta colors described above proceeds, and the end of the color thermal paper 2 shown in FIG.
6, the printing operation of cyan color on the color thermal paper 2 is performed. That is, after the first line of the color thermal paper 2 is positioned immediately adjacent to the preheating heating resistors 55, 55,... Shown in FIG. 3, the preheating pulse voltage having a pulse width PBC becomes the preheating pulse voltage shown in FIG. Are simultaneously applied to the heating resistors 55, 55,...

The pulse width PBC corresponds to the cyan color development start energy TBC. Therefore, the Joule heat generated in the preheating heating resistors 55, 55,... Shown in FIG. 3 moves to one line portion of the color thermal paper 2, and as a result, the one line portion has cyan color. The energy immediately before the start energy TB is applied.

The one-line portion of the color thermal paper 2 corresponds to the preheating heating resistors 55, 55, shown in FIG.
.. Are moved to the vicinity of the printing heating resistors 54, 54,..., And at the same time, the two-line portions of the color thermal paper 2 are placed immediately near the preheating heating resistors 55, 55,. To position.

Then, for example, a gradation pulse voltage having a pulse width PGC corresponding to 180 gradations is applied to the heating resistor 54 for printing shown in FIG. The pulse width PGC corresponds to the cyan gradation energy TGC.

As a result, Joule heat of cyan gradation energy TGC corresponding to the gradation pulse voltage having the pulse width PGC is generated in the heating resistor 54 for printing shown in FIG.
Therefore, the energy of one line portion of the color thermal paper 2 is
Cyan coloring start energy TBC + cyan gradation energy TGC
Value. Thereby, in the cyan recording layer,
The cyan developer transmits through the cyan microcapsules and causes a chemical reaction with the cyan leuco dye. As a result, a 180-color cyan color is generated.

At the same time as the above-described cyan printing, the pulse width P
The BC preheating pulse voltage is applied to the preheating heating resistors 55, 55,... In FIG. Thus, in the same manner as in the above-described operation, the energy immediately before the cyan coloring start energy TBC is applied to the two lines of the color thermal paper 2. Thereafter, in the same manner as the above-described operation, the cyan printing operation for the second line of the color thermal paper 2 and the preheating operation for the third and subsequent lines are performed.

When the printing of the yellow, magenta, and cyan colors described above proceeds and the end of the color thermal paper 2 shown in FIG. 10 is located immediately below the bleaching lamp 21C,
Bleaching is performed on the unprinted portion of the color thermal paper 2 described above. Then, the end of the color thermal paper 2 is conveyed toward the cutter 29 by the feed rollers 28, 28, and the end of the color thermal paper 2 for a fixed length is cut by the cutter 29 and then stored in the storage case 30. Is done.

According to the above-described color printer, for example, in parallel with the printing operation for one line portion heated in advance, the preheating operation for at least two line portions to be printed next is performed on the color thermal paper 2. High-speed printing is possible.

As shown in FIG. 7A, there is almost no difference in the life between the thermal head using the stainless steel substrate of the first embodiment and the thermal head using the conventional alumina substrate. It turns out that there is no problem in practical use. FIG. 7A shows the results of life tests of the thermal head of the conventional example and the thermal head of the first embodiment. The horizontal axis of FIG. 7A indicates the number of gradation control pulses applied to the thermal head. The vertical axis in FIG.
The energy value per pulse is shown, and the thermal head is marked with broken energy. Further, FIG. 7B shows the test results of the effect of applying heat to the thermal head substrate fixed on the heat sink and affecting the wiring pattern on the thermal head. In the conventional partial grace alumina substrate, the wiring pattern on the thermal head substrate is broken at 460 ° C. However, the thermal head substrate of the above embodiment broke at 800 ° C. That is, in the above-described embodiment, the characteristic corresponding to the temperature change is significantly improved as compared with the conventional partial grace substrate.

Next, a second embodiment of the present invention will be described. FIG. 1 is a configuration diagram of a color printer using a thermal head according to a second embodiment of the present invention. In this figure, reference numeral 2 denotes a color thermal paper,
And is fed in the direction of arrow Z shown in FIG.

In FIG. 1, reference numerals 9 and 9 denote feed rollers disposed in the vicinity of the paper feed rolls, respectively, so that their outer peripheral surfaces are in contact with each other. And has the role of transporting in the direction of arrow Z shown in FIG. 1
Reference numeral 0 denotes a platen roller disposed to the right of the feed rollers 9 and 9. Reference numeral 11YN denotes a yellow thermal head disposed above the platen roller 10, and is used when printing yellow. 12Y, 12M and 12C
Is an IC, which controls a heating resistor on each thermal head. (IC12YD, IC12
MD and IC12CD are mounted on stainless plate 52)

Here, the yellow thermal head 11Y
The detailed configuration of D will be described with reference to FIG. In this figure, the yellow thermal head 11 shown in FIG.
It is a perspective view in the state where YD was turned upside down. The thermal head shown in FIG. 8 is a double-line thermal head. Yellow thermal head 11 shown in this figure
In the YD, reference numeral 52 denotes a stainless steel substrate, which is disposed so as to crawl on the surface of the heat sink 51.

Next, the thermal head substrate will be described in detail. FIG. 9 is a plan view of a thermal head substrate constituting the yellow thermal head 11YD. In this figure, reference numeral 52 denotes a thermal head substrate made of stainless steel. Reference numerals 54, 54,... Denote heating resistors for gradation, which are formed in a long shape at regular intervals on the surface of the grace raised portion. These printing heating resistors 54, 5
4,... Are provided corresponding to one dot at the time of printing, and heat generated according to the pulse width of the supplied pulse voltage for gradation control is transferred to a color thermal paper 2 (not shown).
(See FIG. 1).

Reference numerals 54D, 54D,... Denote second gradation heating resistors, which are formed in a long shape at regular intervals on the surface of the raised portion of the grace. Are provided corresponding to one dot at the time of printing, and generate heat generated according to the pulse width of the supplied pulse voltage for gradation control. Each is applied to color thermal paper 2 (not shown) (see FIG. 1).

Reference numeral 56 denotes a common electrode portion formed on the surface of the stainless steel plate 52. One end of each of the common electrodes 56 is electrically connected via the common electrode 57. Are a plurality of individual lead electrodes 58, 58,... Formed on the surface of the stainless steel plate 52 in correspondence with the gradation heating resistors 54, 54,. Are electrically connected to the other ends of the gradation heating resistors 54, 54, respectively. 58D, 58
Are a plurality of lead electrodes formed on the surface of the stainless steel plate 52 so as to correspond to the gradation heating resistors 54D, 54D, respectively. One end of each of the lead electrodes is a gradation heating resistor. 54D, 54D,... Are electrically connected to each other.

The other ends of the lead electrodes 58, 58,...
It has a lead pad section 61. Reference numeral 62 denotes a lead pad, which is connected to each terminal of the control IC 12Y. The terminal of the control IC 12Y and the other end of the gradation heating resistors 54, 54,...
1, electrically connected via a lead wire 63 and a lead pad 62.

Further, the control IC 12Y includes:
A pulse voltage is applied to the heating resistors 54, 54,... Based on the print data of yellow printing supplied from the flexible wiring board via the connection terminal pattern 64 and the lead pad 65 from a control unit (not shown). Is supplied.

The other ends of the lead electrodes 58D, 58D,... Have a lead pad 61D. A lead pad 62D is connected to each terminal of the control IC 12YD. The gradation heating resistors 54D, 54D,.
・ The other end and the terminal of the control IC 12YD
They are electrically connected via a lead pad portion 61D, a lead wire 63D, and a lead pad 62D.

Further, the control IC 12YD
Are connected to a connection terminal pattern 64D and a lead pad 65 from a flexible wiring board by a control unit (not shown).
.. Are controlled based on the print data of yellow printing supplied via D. The pulse voltages are respectively supplied to the heating resistors for printing 54D, 54D,.

Next, the heating resistor portion of the thermal head substrate will be described with reference to FIG. FIG. 4 is a cross-sectional view of the thermal head substrate of FIG. In this figure, 52 is a stainless steel plate. 53a and 53b
Is a grace formed by swelling on the surface of the stainless steel plate 52, and its cross section has a semi-spindle shape. The graces 53a and 53b serve as heat storage materials. 53c is a flat grace. 54 is
The heating resistor for gradation is formed on the grace 53a.

Numeral 54D denotes a gradation heating resistor, which is formed on the grace 53b. Heating resistor for gradation 54
One end of each of the gradation heating resistors 54D is electrically connected to the common electrode portion 56 and the common electrode 57. The other end of the gradation heating resistor 54 is connected to the individual lead electrode 5.
8 is electrically connected. Heating resistor for gradation 54D
Is electrically connected to the lead electrode 58D. Reference numeral 92 denotes a resistor layer that forms the gradation heating resistor 54 and the preheating heating resistor 55. 93
Are the gradation heating resistor 54 and the gradation heating resistor 54
This is a protective film for protecting D. 94 is a backside grace glass.

Here, the thickness of the stainless steel plate 52 is “1”.
mm or less ". In some cases, the thickness of the stainless steel plate 52 is “0.5 mm or less” or
Created with “0.3 mm or less”. Further, the width of the common electrode section 56 is set to “2 mm or less”. Also,
In some cases, the width of the common electrode portion 56 is created to be “500 μm or less” or “100 μ or less”.

Next, the attachment of the stainless steel plate shown in FIG. 9 to the heat sink will be described with reference to FIG. FIG. 5 is a conceptual diagram of a thermal head showing how to attach a stainless steel plate to a curved heat sink. In this figure, 12Y is a control IC. 5
1 is a curved heat sink. Stainless steel plate 52
Is fixed by screws 90 by an oval hole 91 so as to follow the curved heat sink. Reference numeral 95 denotes a flexible wiring board, and a signal for controlling the control IC 12Y is sent from a printer control unit (not shown).

The screwing portion for fixing the stainless steel plate 52 to the heat sink 51 will be described with reference to FIG.
FIG. 6 is a sectional view taken along line BB ′ of the thermal head of FIG. The stainless steel plate 52 is fixed to the heat sink 51 by tightening the screw 90 to the threaded heat sink 51 through the hole 91 of the stainless steel plate 52. Reference numeral 96 denotes a spacer, which is provided in the hole 91 of the stainless steel plate 52.

The screw 90 is fastened to the screw hole of the heat sink 51 via the spacer 96. 97 is a washer,
The stainless plate 52 is pressed so as not to come off the heat sink 51. 98 is a spring washer,
The screw 90 is fixed so as not to be loosened.

Here, the length of the spacer 96 is slightly longer than the thickness of the stainless steel plate 52, for example, up to 100 mm.
Use a spacer that is about μ long. For this reason, the stainless steel plate 52 is not completely fixed to the heat sink 51 by the screws 90. The stainless plate 52 is pressed against the heat sink 51 by the washer 97. That is, the tightening and tightening of the screw 90 causes the stainless steel plate 52
The upper limit of the force that presses the heat sink 51 onto the heat sink 51 is adjusted.

Since the hole 91 has an elliptical shape, if the dimensions of the stainless steel plate 52 and the heat sink are different from the initial state due to the bimetal effect due to the difference in linear expansion coefficient between the stainless steel plate 52 and the heat sink, the screw is fixed. The stainless steel plate 52 slides on the heat sink 51 with 90 as a reference position.
For this reason, since the stainless steel plate 52 slides on the heat sink 51 during operation, the stress due to the stress applied to the stainless steel plate 52 is reduced.

Next, referring to FIG.
Numerals 0 and 20 serve to guide the color thermal paper 2 while sandwiching it. Reference numeral 21Y denotes a yellow fixing lamp disposed above the surface of the color thermal paper 2 and irradiates the light having a peak wavelength of 420 nm to the surface of the color thermal paper 2. That is, the yellow fixing lamp 21Y serves to fix yellow in the yellow recording layer.

The reference numeral 11MD downstream of the yellow fixing lamp 21Y shown in FIG. 1 is a magenta thermal head disposed above the platen roller 23, and is used for printing magenta. This thermal head 11 for magenta
The configuration of the MD is the yellow thermal head 11Y described above.
D (see FIG. 4, FIG. 8, or FIG. 9).

Reference numeral 21M downstream of the magenta thermal head 11MD is a magenta color fixing lamp disposed above the surface of the color thermal paper 2, and the above-mentioned light having a peak wavelength of 365 nm is applied to the surface of the color thermal paper 2. Irradiation. That is, the magenta fixing lamp 21M serves to fix the magenta color on the magenta recording layer.

Reference numeral 26 shown in FIG. 1 is a platen roller disposed downstream of the magenta fixing lamp 21M. 11
The CD is a cyan thermal head disposed above the platen roller 26, and is used when printing cyan. The configuration of the cyan thermal head 11CD is the same as the configuration of the yellow thermal head 11YD (see FIG. 4, FIG. 8, or FIG. 9).

Reference numeral 21C denotes a cyan thermal head 11C.
A bleaching lamp disposed downstream of D. The bleaching lamp irradiates the surface of the color thermal paper 2 with light of a predetermined wavelength. The bleaching lamp 21C has a function of bleaching a non-colored portion of the color thermal paper 2.

Reference numerals 28, 28 denote feed rollers provided below and to the right of the bleaching lamp 21CN, respectively, such that their outer peripheral surfaces are in contact with each other. Reference numeral 29 denotes a cutter disposed to the right of the feed rollers 28, 28, which cuts the end of the color thermal paper 2 into a predetermined length. Reference numeral 30 denotes a storage case disposed on the right side of the cutter 29, in which the color thermal papers 2a, 2a,... Cut by the cutter 29 are stacked and stored.

Next, the operation of the above-described first conventional color printer will be described with reference to FIGS. First, in FIG. 1, when power is supplied to each unit of the apparatus, the feed rollers 9, 9 are driven to rotate by a motor (not shown). As a result, the color thermal paper 2 is conveyed in the direction of arrow Z shown in FIG. Then, when the end of the color thermal paper 2 is positioned on the platen roller 10, the feed rollers 9, 9 are stopped, and the yellow thermal head 11 </ b> YD is pressed against the platen roller 10 via the color thermal paper 2. That is, now, the end of the color thermal paper 2 is connected to the gradation heating resistor 54 of the yellow thermal head 11YD shown in FIG.
, And gradation heating resistors 54D, 54D,.
And the platen roller 10 shown in FIG.

The IC 12Y reads the print data of the first line for the yellow color at the timing of the clock signal immediately before the printing of the first line, and then latches the print data at the timing of the latch signal. Latch into circuit. The print data is data corresponding to each dot in one line. Similarly, IC
12YD is an IC that stores print data for printing the second line
It is read at the same clock as 12Y and latched by a latch circuit (not shown) at the timing of the latch signal.

Next, when a strobe signal is input to the IC 12Y, the IC 12Y is turned on.
4, 54,... Are driven, and the generated Joule heat is used to soften the yellow microcapsules of the yellow recording layer and to apply energy for coloring at the designated gradation density. . That is, the printing operation is performed by driving the gray scale heating resistor with a pulse width at which the yellow microcapsules generate the Joule heat of the yellow coloring start energy TBY and the yellow grayscale energy TGY.

At this time, similarly, when a strobe signal is input to the IC 12YD, the IC 12YD drives the gradation heating resistors 54D, 54D,..., And the generated Joule heat causes the yellow recording layer yellow. An operation of softening the microcapsules and applying energy for color development at a designated gradation density is performed. That is, the printing operation is performed by driving the gray scale heating resistor with a pulse width at which the yellow microcapsules generate the Joule heat of the yellow coloring start energy TBY and the yellow grayscale energy TGY.

For example, assuming that the print data to be printed on the first line is data indicating that yellow tones of 180 gradations should be printed, the IC 12Y includes the heating resistors for printing 54, 54,. And performing a switching operation of conducting the heating resistor and a DC power supply (not shown). Thereby, the printing heating resistor 5 is formed.
, 54,..., A gradation pulse voltage is applied, and the gradation heating pulse voltage is applied to the heating resistor 54 for printing.
, Generate Joule heat.

Then, the energy of the yellow microcapsules in the yellow recording layer gradually rises to the yellow coloring start energy TBY or more due to the Joule heat. As a result, the yellow microcapsules begin to soften, and an external yellow coupler passes through the yellow microcapsules.

Further, the yellow diazo dye and the yellow coupler cause a chemical reaction, and yellow color is generated on the color thermal paper 2. Then, as the energy of the yellow microcapsules increases with the passage of time, the above-described chemical reaction proceeds, and as a result, the gradation of the yellow color increases.

[0120] Similarly, in parallel with the above-described yellow printing operation of the first line, a printing operation for the second line portion of the color thermal paper 2 is performed. That is, IC1
The heating resistor 5 for printing has a gradation pulse voltage of a pulse width for generating Joule heat corresponding to the designated gradation 2YD.
4D, 54D,... As a result, the energy of the yellow microcapsules in the yellow recording layer increases with the passage of time in the same manner as the above-described printing operation of the first line portion, and the gradation of the yellow color increases.

Then, the IC 12Y sets the gradation pulse voltage supplied to the print heating resistors 54, 54,... To zero. At the same time, the IC 12YD sets the gradation pulse voltage supplied to the printing heating resistors 54D, 54D,... To zero. As a result, the energy increase of the yellow microcapsules in the yellow recording layer stops, and the chemical reaction between the yellow microcapsules and the yellow coupler stops.
At this point, a yellow color of 180 gradations has been generated in the yellow recording layer. In this printing operation, dot printing of two lines is completed at the same time.

Next, the platen roller 1 shown in FIG.
0 is rotationally driven by an angle corresponding to two lines, and the color thermal paper 2 is transported by two lines in the arrow Z direction shown in FIG. As a result, the third line of the color thermal paper 2 moves to the position of the gradation heating resistors 54, 54,..., And the fourth line of the color thermal paper 2 becomes the gradation heating resistors 54D, 54D, ..

Further, the IC 12Y receives the clock signal.
After reading the print data of the third line relating to the yellow color at the timing, the print data of the third line is latched by the latch circuit at the timing of the latch signal. Similarly,
The IC 12YD reads the print data of the fourth line relating to the yellow color at the timing of the clock signal, and then latches the print data of the fourth line in the latch circuit at the timing of the latch signal.

Then, similarly to the above-described operation, the IC 12Y includes the heating resistors for printing 54, 54,.
, A gradation pulse voltage is applied to the
2YD applies a gradation pulse voltage to the print heating resistors 54D, 54D,. As a result, the energy of the third and fourth line portions of the color thermal paper 2 increases, and a yellow color is generated in the yellow recording layer by a chemical reaction. This gradation pulse voltage is to generate Joule heat having a value of yellow coloring start energy TBY + yellow gradation energy TGY in each gradation heating resistor. By repeating the above operation, color thermal paper 2
Is printed.

Then, when the above-described yellow printing proceeds and the end portion of the color thermal paper 2 shown in FIG. 1, that is, the portion where the yellow color is generated, is conveyed to just below the yellow fixing lamp 21Y. Then, yellow fixing is performed in the same manner as the above-described operation.

When the end of the color thermal paper 2 is pressed between the magenta thermal head 11MD and the platen roller 23, the yellow thermal head 11
The magenta printing operation is performed in the same manner as the yellow printing operation in YD. That is, in the printing operation of the magenta color, the operation of printing the magenta color on the first and second line portions of the color thermal paper 2 is performed in parallel.

That is, the gradation heating resistors 55, 55,...
. And the gradation heating resistors 55D, 55D,... Are simultaneously provided with a magenta color development start energy TBM and a magenta gradation energy TGY corresponding to the gradation specified by the print data. An adjustment pulse voltage is applied. As a result, the magenta microcapsules in the magenta recording layer are provided with energy having a value of magenta coloring start energy TBM + magenta gradation energy TGM.

As a result, the magenta coupler passes through the magenta microcapsules. As a result, a magenta coupler and a magenta diazo dye cause a chemical reaction in the magenta recording layer, and a magenta color is generated. When the portion of the color thermal paper 2 where the magenta color is generated is located immediately below the magenta fixing lamp 21M, the magenta color is fixed in the magenta recording layer.

Then, the printing of the yellow and magenta colors described above proceeds, and the end of the color thermal paper 2 shown in FIG.
Is performed, a cyan printing operation on the color thermal paper 2 is performed. That is, after the first line of the color thermal paper 2 is located immediately near the gradation heating resistors 54, 54,..., The pulse width at which the Joule heat of the cyan coloring start energy TBC and the magenta gradation energy TGC is generated. A gradation pulse voltage is applied.

At the same time, the gradation heating resistor 54
After the second line of the color thermal paper 2 is positioned immediately near D, 54D,..., A gradation pulse voltage of a pulse width at which Joule heat of cyan color start energy TBC and magenta gradation energy TGC is generated is applied. You. By this printing operation, 2
The cyan printing for the lines is performed simultaneously.

Then, for example, a gradation pulse voltage corresponding to 180 gradations is applied to the heating resistor 54 for printing. The Joule heat generated by the gradation pulse voltage having the above-mentioned pulse width corresponds to the cyan coloring start energy TBC + the cyan gradation energy TGC of the designated gradation.

As a result, Joule heat corresponding to the gradation pulse voltage having the above-mentioned pulse width is generated in the heating resistor 54 for printing shown in FIG. Therefore, the energy of one line portion of the color thermal paper 2 is the cyan coloring start energy TBC +
The value is cyan gradation energy TGC. This allows
In the cyan recording layer, the cyan developer passes through the cyan microcapsules and causes a chemical reaction with the cyan leuco dye. As a result, a 180-color cyan color is generated.

Simultaneously with the cyan printing, a gradation pulse voltage having a pulse width corresponding to the designated gradation is applied to the gradation heating resistors 54D, 54D,. Thus, in the same manner as in the above-described operation, cyan is generated at the designated gradation in the second line portion of the color thermal paper 2. Hereinafter, in the same manner as the operation described above, the color thermal paper 2
The cyan printing operation for the third line and the preheating operation for the fourth and subsequent lines are performed.

Then, when the printing of the yellow, magenta and cyan colors described above proceeds and the end of the color thermal paper 2 shown in FIG. 10 is located immediately below the bleaching lamp 21C,
Bleaching is performed on the unprinted portion of the color thermal paper 2 described above. Then, the end of the color thermal paper 2 is conveyed toward the cutter 29 by the feed rollers 28, 28, and the end of the color thermal paper 2 for a fixed length is cut by the cutter 29 and then stored in the storage case 30. Is done. The heating resistors 55, 5 and 5 for preheating shown in FIG.
5,... Have been described in terms of the configuration formed in each dot unit, but they can also be formed as a solid pattern of resistors that are all connected.

According to the above-described color printer, two lines can be printed on the color thermal paper 2 in parallel, so that high-speed printing is possible. Further, it is also possible to use the heating resistor for gradation 54D of the double head for preheating, and then perform the density adjustment with the heating resistor for gradation 54 to perform the same printing operation as in the embodiment. In this case, since the gradation heating resistor 54D for preheating the thermal head can be controlled in dot units, it is possible to perform selection control such as not to perform preheating for dots that do not need to be printed, and to save power. Further, in the above-described embodiment, in printing, a delicate variation in energy per dot can be controlled at the preheating stage, and control for eliminating density unevenness in a printing result becomes possible.

As described above, the first and second embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the first and second embodiments. The present invention includes any design change or the like within a range not departing from the gist of the present invention. For example, the thermal head according to the first and second embodiments has been described using a thermal paper type color printer, but can also be used for a sublimation printer using an ink ribbon or a fusion type color printer.

[0137]

According to the first aspect of the present invention, there is provided a heat sink having a curved surface and a screw hole formed in the surface, and a substrate having a hole having a diameter larger than the screw hole.
A heat generating resistor formed on the surface of the substrate; and a screw that penetrates the hole and is screwed into the screw hole to attach the substrate along the upper surface of the heat sink. Since the line thermal head can be mounted on a curved heat sink having a different coefficient of thermal expansion by screwing, there is an effect that a printer capable of high-speed printing can be produced without twisting the transport path (pass line) of the printing paper.

According to the second aspect of the present invention, a heat sink having a curved upper surface and a screw hole formed on the surface, a substrate having a hole with a diameter larger than the screw hole, A long electrode portion protrudingly formed on the surface, a heating resistor formed on the surface of the substrate, and the substrate is screwed into the screw hole through the hole and the substrate is along the upper surface of the heat sink. Since it is provided with a screw that is slidably mounted in a direction parallel to the electrode portion, a thermal head with a preheating function and a double-line thermal head can be attached to a bent heat sink having a different coefficient of thermal expansion by screwing. Without twisting the printing paper transport path (pass line)
There is an effect that a printer capable of high-speed printing can be created.

Further, according to the third aspect of the present invention, since the hole is formed as an ellipse having a long diameter in a direction parallel to the electrode portion, the thermal expansion between the thermal head substrate and the heat sink is achieved. There is an effect that deformation of the thermal head substrate caused by the bimetal effect due to the difference in rate can be prevented because the thermal head substrate slides on the heat sink. In addition, according to the fifth aspect of the present invention, since the substrate is formed of a stainless steel material, the metal is easily adapted to bending, so that the metal can be mounted so as to crawl on a heat sink having a curved and bent surface. It can be easily formed, and has high thermal conductivity, which has the effect of improving the efficiency of heat radiation by the heat sink.

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic configuration of a color printer using a thermal head according to an embodiment of the present invention.

FIG. 2 is a perspective view of a thermal head according to an embodiment of the present invention.

FIG. 3 is a plan view showing an external configuration of a thermal head according to an embodiment of the present invention.

4 is a cross-sectional view of the thermal head shown in FIG.

FIG. 5 is a perspective view showing attachment of a thermal head to a heat sink according to one embodiment of the present invention.

6 is a sectional view taken along line B-B 'shown in FIG.

FIG. 7 is a diagram comparing reliability between a conventional thermal head and a thermal head according to an embodiment of the present invention.

FIG. 8 is a perspective view of a thermal head according to a second embodiment of the present invention.

FIG. 9 is a plan view showing an external configuration of a thermal head according to a second embodiment of the present invention.

FIG. 10 is a side view showing a schematic configuration of a color printer using a conventional thermal head.

[Explanation of symbols]

2, 2a color thermal paper 3 sending reel 9 feed roller 10 platen roller 11YN, 11MN, 11CN thermal head 11YD, 11MD, 11CD thermal head 12Y, 12M, 12C control IC 12YD, 12MD, 12CD control IC 21Y, 21M, 21C color fixing Lamps (Bleaching lamps) 23, 26 Platen roller 28 Feed roller 29 Cutter 30 Storage case 51 Heat sink 52 Stainless steel plates 53a, 53b, 53c Grace 54, 54D Heating resistor for gradation (heating resistor for printing) 55 Heating resistor for preheating Body 56 Common electrode part 57 Common electrode 58, 58D Individual lead electrode 59 Lead electrode 60 Power transistor 61, 61D Lead pad part 62, 62D Lead pad 63, 3D lead 64,64D connecting terminal patterns 65,65D lead pad 90 Screw 91 Screw hole 94 backside Grace glass 95 flexible wiring board 96 spacer 97 washers 98 spring washer

Claims (8)

[Claims] A heat sink having a curved surface and a screw hole formed in the surface; a substrate having a hole having a diameter larger than the screw hole; a heating resistor formed on the surface of the substrate; A screw that penetrates the hole and is screwed into the screw hole to attach the substrate along the upper surface of the heat sink. 2. A heat sink having a curved upper surface and a screw hole formed in the surface thereof, a substrate having a hole having a diameter larger than the screw hole, and a long shape projecting from the surface of the substrate. An electrode portion; a heating resistor formed on the surface of the substrate; and a screw that penetrates the hole and is screwed into the screw hole to move the substrate along the upper surface of the heat sink in a direction parallel to the electrode portion. The thermal head according to claim 1, further comprising: a screw for slidably mounting the substrate. 3. The thermal head according to claim 1, wherein the hole is formed as an ellipse having a long diameter in a direction parallel to the electrode portion. 4. An output terminal connected to one end of the heating resistor, between the one end of the heating resistor and the other end of the heating resistor grounded according to print data. 4. The thermal head according to claim 1, further comprising control means for applying a pulse voltage having a variable pulse width. 5. The thermal head according to claim 1, wherein the substrate is formed of a stainless steel material. 6. The thermal head according to claim 1, wherein the thickness of the substrate is more than 0 and 1 mm or less. 7. The thermal head according to claim 1, wherein the width of the electrode portion is more than 0 and 2 mm or less. 8. The thermal head according to claim 1, wherein the insulator is formed of a glass material.