JPH11334126A - Heat-generating resistance body, thermal head and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously satisfy the conflicting requirements of heat dispersion and heat concentration by setting a gap at a center of a heat-generating resistance body on the occasion of sublimation type printing thereby dispersing heat, and setting a heat concentration area on the occasion of thermal melt type printing thereby concentrating heat. SOLUTION: A slit 4 of a breadth 10 μm is formed at a center in a sub scan direction of a heat-generating resistance body 1 of a size of 170 μm in a main scan direction and 270 μm in the sub scan direction. At the same time, a heat-generating resistance body missing part 3 of a square of 40 μ×90 μm is formed to free heat both at the upper right side of a heater where a paper feed is started, and at the lower left side of the heater where the paper feed is finished. Moreover, the heat-generating resistance body missing part 3 at the side where the paper feed is finished is set continuously with the slit 4. A distance in the sub scan direction between the two heat-generating resistance body missing parts 3 is one paper feed pitch of 300 dpi, i.e., approximately 90 μm. A heat concentration area of a part other than the heat-generating resistance body missing parts becomes a current clog part. Supposing that a current runs from the upper side to lower side, resistance values of a pair of right and left heat-generating resistance bodies become equal structurally and therefore the current runs uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating resistor suitable for use in a full-color printer for both a fusion type and a sublimation type, and a thermal head to which the heating resistor is applied.

[0002]

2. Description of the Related Art A thermal head has advantages such as low noise, low maintenance cost and low running cost. Therefore, a thermal head is widely used for a thermal recording apparatus of various type A equipment such as a facsimile, a video printer and a plate making machine. It has become.

Generally, a thermal head has the following configuration. That is, after a heating resistor layer and a conductive layer such as aluminum are formed on an alumina substrate, a plurality of heating resistors and electrode patterns are formed by a photoetching process. Further, a protective layer for protecting the plurality of heating resistors and the electrode patterns is formed by a thin film forming method such as a sputtering method. In many cases, a glass glaze layer whose main purpose is to improve surface smoothness and heat storage is provided between the alumina substrate and the heating resistor layer.

Conventionally, as a halftone recording method of a thermal transfer recording apparatus for printing and printing image data using such a thermal head, there are sublimation type thermal transfer recording and fusion type thermal transfer recording.

[0005] In the fusion type thermal transfer recording, realizing the density gradation on a pixel-by-pixel basis is particularly difficult because a stable pixel cannot be formed in a low gradation region, and it is difficult to control the shape and size. There has been proposed a method of expressing image points in a sparse and dense manner, such as a dither method which is a matrix method. However, in this method, since a plurality of (n × n) heating resistors are regarded as one pixel, the resolution is reduced to 1 / n. Therefore, in order to compensate for this, a method has been proposed in which the shape of the heating resistor of the thermal head is devised so that heat is concentrated at the center of the heating, thereby stabilizing the image point in the low gradation area.

On the other hand, in the sublimation type system, as shown in FIG. 4, a slit is provided at the center of the heating resistor so as to prevent shading inside the image point. The device has been devised to reduce it.

That is, since the structure required for the heat generating resistor of the thermal head is essentially opposite between the heat melting type and the sublimation type, the heat generating resistance suitable for the sublimation type is currently used in the sublimation / melting full-color printer. Do you give up improving the image quality of the fusion mold by incorporating the body,
Or, conversely, there is no alternative but to give up a sublimation type image quality by incorporating a heating resistor suitable for a melting type.

[0008]

As described above, in the conventional thermal head of a conventional full-color printer for both sublimation and heat melting, in the case of the heat melting type, the shape of the heat generating resistor is such that heat is concentrated at the center. In the case of the sublimation type, a heating resistor that simultaneously satisfies the conflicting requirements of dispersing heat in the shape of the heating resistor has been desired.

Therefore, the present invention contradicts the image quality in a fusion type / sublimation type printer having a shape that simultaneously satisfies the concentration of heat generated during the fusion transfer and the heat distribution during the sublimation type without compromising the image quality. It is an object of the present invention to provide a heating resistor, a thermal head, and a method of manufacturing the same, which simultaneously satisfy requirements.

[0010]

According to a first aspect of the present invention, there is provided a heating resistor, comprising: a first heating resistor portion having a first heat concentration region and a first heat relaxation region; And a second heat-generating resistor portion having a heat-concentration region and a second heat-mitigation region, and a first heat-generating resistor portion and a second heat-generating resistor portion are provided between the first heat-generating resistor portion and the second heat-generating resistor portion. There is a gap, and the first thermal relaxation region and the second thermal relaxation region have substantially the same area.

According to the heating resistor according to the present invention, in sublimation printing, a gap is provided at the center of the heating resistor.
By disposing the slits, it is possible to disperse the heat generated when the heat generating resistor generates heat. Further, depending on the manufacturing conditions, the slit may be provided not only in the heating resistor but also in the electrode. Further, by providing the thermal relaxation region, an excessive thermal gradient of the heating resistor is prevented from being generated in the sublimation printing, and the image quality is not deteriorated. On the other hand, in the heat melting type printing, by providing a heat concentration region, that is, a current bottleneck, heat concentration required for the heat melting type printing can be realized, and a stable image point can be obtained in a low gradation region. Therefore, it is possible to have a gradation for each image point. In this manner, conflicting requirements in sublimation printing and hot-melt printing can be simultaneously satisfied.

According to a second aspect of the present invention, in the heating resistor, the first or second thermal relaxation region is formed by the first or second thermal relaxation region.
Characterized in that it is formed by removing the heat-generating resistor portion.

According to the heat generating resistor according to the present invention, by removing the heat generating resistor portion to form a heat relaxation region, an excessive heat gradient of the heat generating resistor is prevented in sublimation printing. The image quality is not degraded. on the other hand,
In the hot-melt printing, by providing a heat-concentration area, that is, a current bottleneck, heat concentration required for hot-melt printing can be realized, and a stable pixel can be obtained in a low gradation area. Therefore, it is possible to have a gradation for each pixel. In this manner, conflicting requirements in sublimation printing and hot-melt printing can be simultaneously satisfied.

According to a third aspect of the present invention, in the heat generating resistor according to the first aspect of the present invention, the first heat relaxing region is provided on a side of the first heat generating resistor portion on which the recording medium is conveyed, and the second heat generating resistor is provided. The distance between the first thermal relaxation area and the second thermal relaxation area in the transport direction of the recording medium is provided on the body portion on the transport end side of the recording medium. The length of the first thermal relaxation region in a direction that is equal to the minimum distance to be performed and that is orthogonal to the transport direction of the recording medium is half the length of the first heating resistor portion, and is orthogonal to the transport direction of the recording medium. The second in the direction of
Is characterized in that the length of the heat relaxation region is half the length of the second heating resistor portion.

According to the heating resistor according to the present invention, the distance between the first thermal relaxation area and the second thermal relaxation area is set such that the recording medium is conveyed in the direction in which the recording medium is conveyed (sub-scanning direction). And the direction perpendicular to the direction in which the recording medium is conveyed (main scanning direction) is defined as a half length of the first and second heating resistors, respectively. By arranging them at equal intervals, the influence of the interaction between the first heating resistor portion and the second heating resistor portion can be reduced. The gap may be formed continuously with either the first thermal relaxation region or the second thermal relaxation region.

In the heating resistor of the present invention, the distance of the heating resistor in the sub-scanning direction is L0, the distance of the heat relaxation region in the sub-scanning direction is L, and the distance of each heating resistor in the main scanning direction is L. Is W0, and the distance in the main scanning direction of the thermal relaxation area or the heat concentration area is W, the configuration is such that the following equation is satisfied.

[0017]

(Equation 1)

(Equation 2) The smaller the width of the gap in the heating resistor of the present invention, the larger the area of the heat relaxation region becomes, that is, it is preferable because the temperature gradient can be made gentler. However, with the current etching technology, it is formed at the center of the heating resistor. The width of the gap must be at least 10 μm or more.

In the heating resistor according to the present invention, the minimum transport unit of the recording medium, which is the distance between the first thermal relaxation area and the second thermal relaxation area, depends on the printing resolution. The resolution of printing performed on the recording medium is not particularly limited, and examples thereof include printers of 150 dpi, 300 dpi, 600 dpi, and the like.

According to a fourth aspect of the present invention, there is provided a thermal head including the above-described heating resistor formed on a supporting base, and electrodes connected to the heating resistor.

According to the thermal head of the present invention, in the sublimation type printing, the gap, that is, the slit is provided at the center of the heating resistor, thereby realizing the dispersion of the heat generated when the heating resistor is heated. Can be. In addition, the provision of the thermal relaxation region prevents an excessive thermal gradient of the heating resistor from occurring, and prevents image quality from deteriorating. On the other hand, in the heat melting type printing, by providing a heat concentration region, that is, a current bottleneck, heat concentration required for the heat melting type printing can be realized, and a stable image point can be obtained in a low gradation region. Therefore, it is possible to have a gradation for each image point. In this manner, conflicting requirements in sublimation printing and hot-melt printing can be simultaneously satisfied.

The resolution of the thermal head formed by using the heat generating resistor of the present invention is not particularly limited, but is 140 to 30.
0 dpi.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a thermal head, comprising the steps of: forming a heating resistor on a supporting base; forming an electrode layer on the heating resistor; Patterning the support base on which the electrodes are formed, forming a gap in the heating resistor and equally dividing the heating resistor into a first heating resistor having a first heat concentration region and a first heat relaxation region Patterning the heating resistor by forming a second heating resistor portion having a portion, a second heat concentration region and a second heat relaxation region; and the patterned heating resistor Forming a protective layer so as to cover at least the heat-generating portion.

According to the method of manufacturing a thermal head according to the present invention, in sublimation printing, by providing a gap, that is, a slit in the center of the heating resistor, the heat generated when the heating resistor generates heat is dispersed. Can be realized.
Further, depending on the manufacturing conditions, the slit may be provided not only in the heating resistor but also in the electrode. Further, by providing the thermal relaxation region, an excessive thermal gradient of the heating resistor is prevented from being generated in the sublimation printing, and the image quality is not deteriorated. On the other hand, in hot-melt printing,
By providing a heat concentration area, that is, a current bottleneck, heat concentration required for hot-melt printing can be realized,
Since a stable image point can be obtained in a low gradation area, it is possible to have a gradation for each image point. In this manner, conflicting requirements in sublimation printing and hot-melt printing can be simultaneously satisfied.

According to a sixth aspect of the present invention, in the method of manufacturing a thermal head, the first or second thermal relaxation region is formed by removing the first or second heating resistor portion. And

According to the method of manufacturing a thermal head according to the present invention, an excessive heat gradient of the heating resistor is generated in the sublimation printing by removing the heating resistor portion to form a heat relaxation region. Preventing the image quality from deteriorating. On the other hand, in hot-melt printing, the heat concentration area,
That is, by providing a current bottleneck, heat concentration required for hot-melt printing can be realized, and a stable image point can be obtained in a low gradation area. Becomes possible. In this manner, conflicting requirements in sublimation printing and hot-melt printing can be simultaneously satisfied.

According to a seventh aspect of the present invention, in the method of manufacturing a thermal head, the first thermal relaxation region is provided on a recording medium conveyance start side of the first heating resistor portion, and The thermal relaxation area is provided on the second heating resistor portion on the side of the recording medium transport end position, and the first thermal relaxation area and the second thermal relaxation in the transport direction of the recording medium. The distance of the area is equal to the minimum distance at which the recording medium is conveyed by the conveyance mechanism, and the length of the first thermal relaxation area in a direction orthogonal to the conveyance direction of the recording medium is equal to the first heating resistor portion. And the length of the second thermal relaxation region in a direction orthogonal to the transport direction of the recording medium is half the length of the second heating resistor portion.

According to the method of manufacturing a thermal head according to the present invention, the distance between the first thermal relaxation area and the second thermal relaxation area is determined by changing the distance (sub-scanning direction) in which the recording medium is conveyed. Is the minimum unit distance (paper feed pitch) that is conveyed, and in the direction (main scanning direction) orthogonal to the direction in which the recording medium is conveyed, the length is half the length of the first and second heating resistors, respectively. By arranging them at equal intervals, the influence of the interaction between the first heating resistor portion and the second heating resistor portion can be reduced.
The gap may be formed continuously with either the first thermal relaxation region or the second thermal relaxation region.

In the method of manufacturing a thermal head according to the present invention, the distance between the heating resistor and the heating resistor in the sub-scanning direction is L.
0, the distance in the sub-scanning direction of the thermal relaxation area is L, and the distance in the main scanning direction of each heating resistor portion is W0.
Assuming that the distance in the main scanning direction between the thermal relaxation region and the heat concentration region is W, the configuration is such that the following equation is satisfied.

[0029]

(Equation 3)

(Equation 4) In the method for manufacturing a thermal head according to the present invention, the narrower the width of the gap in the heating resistor is, the larger the area of the thermal relaxation region is, that is, the temperature gradient can be made gentler. The width of the gap formed in the center of the body needs to be at least 10 μm or more.

In the method of manufacturing a thermal head according to the present invention, the minimum unit for transporting the recording medium, which is the distance between the first thermal relaxation area and the second thermal relaxation area, depends on the printing resolution. The resolution of printing performed on the recording medium is not particularly limited, but may be, for example, 150 dpi, 300 dpi, 60 dpi.
A printer such as 0 dpi is exemplified.

The method of manufacturing the heating resistor and the thermal head according to the present invention will be specifically described.

First, a glass glaze layer is formed on a ceramic supporting substrate. Next, the heating resistor layer of the present invention is formed on the glaze layer by a sputtering method. The sputtering is performed in an atmosphere of an inert gas and oxygen with a pressure, an applied power, and time appropriate for the sputter target material. Heat treatment may be performed for the purpose of stabilizing the heat generating resistor layer.

Subsequently, an electrode layer is formed on the heating resistor layer, and a lead electrode including an individual electrode and a common electrode is formed by a photoetching process so as to form a heating section on the heating resistor layer.

Next, a slit having a width of 10 μm is formed in the heating resistor in the sub-scanning direction, which is the paper feeding direction, to divide the heating resistor equally.
Two heating resistor portions are formed. Further, a defective portion for releasing heat is provided in each heating resistor portion. One defect is provided on the paper feed start side, and the other is provided on the paper feed end side.
Further, one missing portion is provided continuously with the slit, and the other missing portion is provided apart from the slit. The distance between the two defective portions in the sub-main inspection direction is equal to one pitch of the paper feed (depending on the printing resolution). The length of the defective portion in the main scanning direction orthogonal to the sub-main inspection direction is half the length of each heating resistor portion.

The slit formed in the sub scanning direction extends to the lead electrode in the paper feeding direction beyond the sub scanning direction of the heating resistor. Similarly, the defect provided continuously with the slit extends to the lead electrode.

The above-mentioned slits and defective portions are formed simultaneously with the patterning of the electrodes. Therefore, it is impossible to provide a slit and a defect only in the heating resistor,
A slit and a deficient portion are inevitably formed also in the electrode portion.

Examples of the shape of the defective portion include a square and a rectangle, and those having rounded corners.

Finally, a protective layer 7 is formed thereon to form a thermal head.

Hereinafter, materials used for the heating resistor and the thermal head of the present invention will be described.

The material of the heating resistor of the present invention is not particularly limited. For example, a nitride of a highly stable metal material such as nickel, chromium, tantalum or the like, or Ta-Si-
Cermets such as O-based and Nb-Si-O-based are exemplified.
The specific resistance value of the heating resistor is about 100 mΩ · cm,
Especially when used in video printers, the change in resistance
1% or less. Further, the thickness of the heating resistor of the present invention is about 0.02 to 0.2 μm.

As the support substrate used in the thermal head of the present invention, various ceramic materials such as alumina ceramics can be used. Materials may be added.

Further, when a glass glaze layer is provided on the supporting substrate, it is formed to a thickness of about 30 to 70 μm by a printing method or the like. As the glass glaze layer, SiO ₂
The main component is, for example, Ca, Ba, A
It may be a mixture of impurities such as l and Sr. The glass transition point of the glass glaze layer is desirably 670 ° C. or higher in order to prevent an increase in the resistance value of the thermal head. Si-N- instead of glass glaze layer
A film made of O-based or the like may be formed.

As an electrode, a commonly used A
1, Al-Si, Al-Si-Cu, etc. are used,
There is no particular limitation. The electrode has a thickness of about 1 to 3 μm.

The protective layer formed on the heating resistor array and the electrodes is usually a Si-ON-based protective layer, and a target material composed of silicon nitride and silicon dioxide, which are ordinary components, is used. It is formed by the used sputtering method.

[0045]

FIG. 1 is a plan view of a heating resistor and a thermal head according to an embodiment of the present invention.

In this embodiment, it is assumed that a thermal head of 144 dpi is used at a paper feed of 300 dpi.

Although not particularly shown, a glass glaze layer made of silicon dioxide is formed on a support substrate made of alumina ceramics by a printing method, and then a Ta-SiC-O cermet is used to form a glass glaze layer on the glass glaze layer. S
A target made of iC-SiO ₂ was placed under an atmosphere of Ar and O ₂ (flow rate 50 sccm) at a pressure of 1 × 10 ^{-2 to} 1.5.
The heating resistor layer was formed by high-frequency bipolar sputtering under the conditions of × 10 ^-2 Torr and applied power of 3 to 5 kW for 3 minutes. Heat treatment may be performed for the purpose of stabilizing the heat generating resistor layer.

Subsequently, an electrode layer made of Al-Si is formed on the heating resistor layer, and a lead formed of an individual electrode and a common electrode is formed by a photoetching process so that a heating portion is formed on the heating resistor layer. The electrode 5 was formed.

Next, the width of the heating resistor 1 of 170 μm in the main scanning direction and 270 μm in the sub-scanning direction is set at the center in the sub-scanning direction.
Insert 4 μm slits and 4
The heating element defective portion 3 of 0 μm × 90 μm square is placed on the paper feeding start side,
That is, they are provided on the upper right side of the right heater in FIG. 1 and on the paper feed end side, that is, on the lower left side of the left heater in FIG. Further, the heating element defective portion 3 on the paper feeding end side is provided continuously with the slit 4. The distance between the two heating element defective portions 3 in the sub-main inspection direction is about 90 μm, one pitch for feeding the paper at 300 dpi. The heat concentration region of the remaining portion of the heating resistor defective portion 3 becomes a current bottleneck portion. In the present embodiment, the slit extends to the electrode due to the manufacturing conditions, but this is not an essential component of the heating resistor of the present invention.

In the case of the heater having this shape, if the current flows from the upper side to the lower side in FIG. 1, the resistance values of the left and right heating resistors are structurally the same, so that the current flows evenly. The heat concentration region 2 between the heat generating resistor defective portion 3 and the slit 4 on the upper right side in FIG. 1 and the left side of the heat generating resistor defective portion 3 on the lower left side in FIG.

FIG. 3 is a schematic view showing a simulation of the heat generation state of the heat generating resistor of the first embodiment by the finite element method. It was found that the sample No. 2 was generating heat. Also, from the simulation results, the center of heat generation is isolated according to the shape of the heating resistor,
It was also found that the temperature gradient was not excessive.

FIG. 2 shows a modified embodiment of the present invention.
According to the present invention, as shown in FIG. 2, a structure in which the heat generating resistor defective portion 3 is provided on the opposite side may be adopted.

[0053]

According to the heating resistor of the present invention, the thermal head using the same, and the method of manufacturing the same, in sublimation printing, a gap is provided at the center of the heating resistor so that the heating resistor can generate heat when heated. Dispersion of the generated heat can be realized, and by providing the heat relaxation region, an excessive heat gradient of the heating resistor is prevented from occurring, and the image quality is not deteriorated. On the other hand, in hot-melt printing, by providing a heat-concentration region, heat concentration required for hot-melt printing can be realized, and a stable image point can be obtained in a low gradation region. It is possible to have a gradation for each pixel. In this manner, conflicting requirements in sublimation printing and hot-melt printing can be simultaneously satisfied.

[Brief description of the drawings]

FIG. 1 is a plan view of a heating resistor according to an embodiment of the present invention.

FIG. 2 is a plan view of a heating resistor according to a modified embodiment of the present invention.

FIG. 3 is a diagram showing a result of a heat generation simulation of the heating resistor according to the present invention by a finite element method.

FIG. 4 is a plan view of a heating resistor in a conventional sublimation type printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Heating resistor 2 ... Heat concentration area 3 ... Heating resistor missing part 4 ... Slit 5 ... Lead electrode

Claims (7)

[Claims] 1. A first heating resistor portion having a first heat concentration region and a first heat relaxation region, and a second heating resistor portion having a second heat concentration region and a second heat relaxation region. A heating resistor portion comprising: a first heating resistor portion and a second heating resistor portion; and a gap between the first heating resistor portion and the second heating resistor portion. A heating resistor, wherein the second thermal relaxation region has substantially the same area. 2. The heating resistor according to claim 1, wherein the first or second thermal relaxation region is formed by deleting the first or second heating resistor portion. body. 3. The first heat relaxation area is provided on a recording medium conveyance start position side of the first heating resistor portion,
The second thermal relaxation area is provided on the second heating resistor portion on the side of the recording medium transport end position, and the first thermal relaxation area and the second thermal relaxation area in the transport direction of the recording medium. Is equal to the minimum distance at which the recording medium is conveyed by the conveyance mechanism, and the length of the first heat relaxation area in a direction orthogonal to the conveyance direction of the recording medium is the first heat generation area. 2. The device according to claim 1, wherein a length of the second thermal relaxation region in a direction perpendicular to a conveying direction of the recording medium is a half of the resistor portion, and is half of a length of the second heating resistor portion. Or 2
The heating resistor as described. 4. A thermal head comprising: the heating resistor according to claim 1 formed on a supporting base; and an electrode connected to the heating resistor. 5. A step of forming a heating resistor on a supporting base, a step of forming an electrode layer on the heating resistor, and patterning the supporting base on which the heating resistor and the electrodes are formed, A first heat-generating resistor portion having a first heat-concentrated region and a first heat-mitigating region formed by equally dividing the heat-generating resistor by forming a gap, a second heat-concentrated region, and a second heat-concentrated region; Patterning the heating resistor by forming a second heating resistor portion having a thermal relaxation region; and forming a protective layer so as to cover at least the heating portion of the patterned heating resistor. A method of manufacturing a thermal head. 6. The method according to claim 5, wherein the first or second thermal relaxation region is formed by removing the first or second heating resistor portion. 7. The first heat relaxation area is provided on a side of a recording medium conveyance start position of the first heating resistor portion,
The second thermal relaxation area is provided on the second heating resistor portion on the side of the recording medium transport end position, and the first thermal relaxation area and the second thermal relaxation area in the transport direction of the recording medium. Is equal to the minimum distance at which the recording medium is conveyed by the conveyance mechanism, and the length of the first heat relaxation area in a direction orthogonal to the conveyance direction of the recording medium is the first heat generation area. 6. The length of the second thermal relaxation area in a direction perpendicular to the conveyance direction of the recording medium, which is a half of the resistor portion, is half the length of the second heating resistor portion. 7. Or 6
The manufacturing method of the thermal head described in the above.