JPS6244467A - Perforated type thermal head and its preparation - Google Patents

Abstract

PURPOSE:To provide a perforated type thermal head capable of obtaining good image quality when adapated to thermography, by providing a large number of ink passing holes to a heat generator substrate composed of a material having high rigidity and good heat conductivity so as to pierce through the groove part of flat surface part of said substrate and mounting a heat generator onto the substrate the peripheral edge of each ink passing hole. CONSTITUTION:A perforated type thermal head is prepared as follows. A groove 15 adjusting the thickness of a heat generator ceramic substrate having a thickness of 1mmm to 100mum is formed to the region including a heat generator forming scheduled position on said substrate 10. The output of laser beam is enhanced by a lens to form seven clear columnar ink passing holes 7 each having a diameter of 10mum and free of the formation of a molten substance at the heat generator forming scheduled position. Next, the substrate is washed and a SiO2 film 14 is subsequently adhered onto the heat generator forming scheduled surface of the heat generator substrate 10 in a thickness of 1-10mum. This SiO2 film 14 functions as the insulating layer of the heat generator substrate 10 when said substrate 10 has electric conductivity. A resistance film 11 is formed o the SiO2 film 14 and a lead film 12 comprising, for example, Ni, Cr or Au is formed on said resistance film 11.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a new recording method, thermal rheophotography, which makes it possible to remove the ink film that is necessary in thermal transfer recording methods used in recording devices such as facsimiles and printers. The present invention relates to a porous thermal head suitable for photography and a method for manufacturing the same.

(Prior Art) Fig. 11 is an explanatory diagram showing the principle of a conventional thermal transfer recording method, in which 1 is a transfer film, 2 is a recording paper (recording medium), 3 is a thermal head, 4 is a heating element, and 5 is a pressure roller. It is. As shown in the figure, the transfer film 1 is a base film 1a such as Mylar film or capacitor paper coated with ink ff1b, and the thermal head 3, transfer film 1, and recording paper 2 are pressed together by a pressure roller 5. When the heating element 4 in the thermal head 3 generates heat in response to the image signal, the ink layer 1b adjacent to the heating element 4 melts, and the ink is transferred onto the recording paper 2. As a result, an ink layer is formed on the recording paper 2. Note that at the same time as the recording paper 2 runs, the transfer film 1 also runs, and a new ink layer is always fed out.

By the way, in the case of this conventional thermal transfer recording method, since the transfer film 1 is constantly fed out, a used transfer film is generated every time a desired recording surface is obtained. Therefore, it is necessary for the device to have a built-in mechanism for winding up the used transfer film 1, or to dispose of the used transfer film 1 after each transfer outside the device. Furthermore, although the recording paper 2 is plain paper and is often inexpensive, the transfer film 1 is expensive, and the recording cost per copy is high, and there are problems in that it takes time and effort to attach and dispose of the transfer film 1. there were.

Therefore, the present inventors invented a new recording method that allows the transfer film to be removed first (hereinafter referred to as thermal rheography).

FIG. 12 shows an example of the configuration of thermal rheography. In the figure, 6 is a porous thermal head, 7 is an ink passage hole, 8 is an ink container, and 9 is ink.

The porous thermal head 6 has holes formed in the heating element of the thermal head to allow ink to pass through.
An enlarged view of an example of the configuration is shown in FIG. In Figure 13, 1
0 is a substrate, 11 is a resistor, 12 is a lead, and 13 is a protective film. Ink 9 is a semi-solid ink whose fluidity changes significantly upon heating. The pressure roller 5 presses the recording paper 2
It is used to bring the ink passage hole 7 of the porous thermal head 6 into contact with the ink passage hole 7 of the porous thermal head 6.

The recording principle of thermal rheography will be explained using FIG. 12. Normally, the semi-solid ink 9 is held by the ink container 8 and the porous thermal head 6, and the semi-solid ink 9 is not transferred onto the recording paper 2, but the heating element 4 of the porous thermal head 6 responds to the image signal. By selectively applying electricity and heating, the semi-solid ink 9 near the heating element 4 is heated and melted, its fluidity is significantly improved, and the molten ink passes through the ink passage hole 7 and is deposited on the recording paper 2. Attaches and absorbs. With this, a desired recording surface can be obtained. In addition, after recording, the heating element 4
There is a shortage of semi-solid ink 9 in the vicinity of , but this is replenished from surrounding ink. For this purpose, a semi-solid ink is used which has some fluidity at room temperature. Further, in order to smoothly replenish the ink, pressure is applied to the semi-solid ink 9 from above the ink container 8.

As a specific example shown in FIG.
-116685 and Japanese Patent Application No. 59-197964, he invented a porous thermal head in which the substrate 10 is made of Si and polyimide resin, respectively, and a method for manufacturing the same.

(Problems to be Solved by the Invention) However, in the case of the above-mentioned porous-type multi-head, when the substrate 10 is 3i, the single crystal wafer has a cleavage property and must be carefully handled during its cracking and manufacturing. In the case of polyimide resin, its thermal conductivity is low, and in order to improve heat dissipation to the substrate 10, the thickness of the substrate 10 must be made thin, but this is accompanied by technical difficulties; In the conventional manufacturing method of a porous thermal head, when the substrate 10 is 3i, the shape of the ink passage hole 7 is changed due to the generation of molten material etc., because the melt processing method is simply irradiating the substrate 10 with a laser beam. It is difficult to form the heating element 4 in this area because it is not clear and molten material (oxide) tends to accumulate at the frontage of the ink passage hole 7. Also, if the heating element 4 is processed after formation, a part of the heating element may be damaged. When the substrate 10 is made of polyimide resin, side etching occurs due to non-directional etching using hydrazine or the like as an etching solution, and the pores in the substrate 10 become dovetail-like. Therefore, there is a problem that it is difficult to form fine ink passage holes 7 of arbitrary shapes in one heating element 4, and there is a problem that image quality deteriorates.

(Object of the Invention) In order to eliminate these problems, the object of the present invention is to provide a porous thermal head that can be applied to thermal photography and obtain good image quality, and a method for manufacturing the same.

(Means for Solving the Problems) In order to achieve the above object, the first invention includes a heating element substrate made of a material having high rigidity and good thermal conductivity, and a heating element substrate made of a material having high rigidity and good thermal conductivity, The invention is characterized by comprising a large number of ink passage holes provided, and a heating element made of an insulating film, a resistive film, and a lead film connected to the resistive film provided on a substrate at least at the periphery of each ink passing hole. . Further, the second invention includes a step of forming a groove or a flat surface on one side of a heating element substrate made of a material with high rigidity and good thermal conductivity, and forming an ink passage hole at a position where the heating element is formed on the heating element substrate. a step of forming an insulating film on one side of the heating element substrate, a step of attaching a resistive film and a lead film on the insulating film, and alignment with the ink passage holes, and then inserting the eight heating elements. and the step of forming a lead group, and the process of protecting the heating element group.
The method is characterized by comprising a step of forming a wear protection film.

(Function) According to the porous thermal head according to the first invention, since the substrate is made of a material with high rigidity and good heat conduction, the shape of the ink passage holes, which are minute holes, is not deformed and is clearly defined. At the same time, since the heating element has a good heat decay, a recording side with good image quality can be obtained. According to the method for manufacturing a porous thermal head according to the second invention, oxidation or corrosion of the heating element does not occur, fine ink passage holes are clearly formed at desired positions in the heating element, and the shortest possible time is achieved. In a time process, a porous thermal head can be produced that can be used to obtain good image quality.

(Example) FIG. 1 is a sectional view illustrating a first example of a porous thermal head manufactured according to the present invention, and the same components as those of the conventional example are denoted by the same reference numerals.

That is, 7 is an ink passage hole, 8 is an ink container, and 10 is a heating element substrate, which is made of Si3N4. For example, 14 is 5i
An insulating film made of 0.02 is provided on the lower surface of the substrate 10.

11 is a heating element made of a resistive film, for example Ta-8iO2
etc., and is provided on the insulating film 14. 12 is a lead film formed on the resistive film 11, for example, AI, Au.
, Ni, etc. 13 is a wear-resistant protective film such as TaO2,
15 is a groove. FIG. 2 is a bottom view with the protective film 13 of FIG. 1 removed.

To avoid this, it is necessary to pass the heating element 1 through the lead film 12.
1, and the recording principle has already been described. Although not shown in the figure, a heating element driving IC is mounted on the heating element substrate 10, and selectively energizes a large number of heating element groups according to image signals through a large number of lead film groups. drive

Next, FIG. 3 for explaining the manufacturing method of the above-mentioned porous thermal head shows grooves 15 or ink passage holes 7 in the heating element substrate 10.
This is one configuration example of an apparatus used to form a . 16
17 is an etching liquid reservoir, 17 is a laser oscillator, 18 is a translucent mirror, 19 is a convex lens; 20 is a television motor, 21 is an etching processing container, 22 is a table, 23 is an XY stage, 24 is a barrier pull valve, and 25 is a branch pipe. , 26 is an etching liquid delivery pipe, 27 is a pump, 28 is a barrier pull valve,
29 is an etching liquid supply pipe, and 30 is an etching liquid. For example, KO day solution is used as the etching solution. If the chemical atmosphere is a gas, remove the pump 27 and etching liquid storage tank 16 and directly supply the etching liquid to the etching liquid delivery pipe 26.
A pressure reducing valve and a gas cylinder are connected to the etching liquid insertion tube 29, and a valve and a vacuum pump are connected, respectively.

To operate the apparatus shown in FIG. 3, it is sufficient to irradiate laser light onto the heating element substrate 10 from the laser oscillator 17 while circulating the etching liquid 30. As a result, the irradiated area is processed at a predetermined processing speed. For example, X-Y stage 2
3, by moving the laser irradiation location on the substrate 10, grooves and ink passage holes of arbitrary shapes can be formed.

The porous thermal head shown in FIGS. 1 and 2 is manufactured, for example, in the following manner. A ceramic heating element substrate 10 with a thickness of 1 mm is processed according to the processing procedure as explained in FIG.
First, a groove 15 is formed on the substrate 10 so that the thickness of the substrate 10 is 100 μm in an area that includes the planned position of the heating element, and then the laser beam diameter is narrowed down using a lens 19, and the laser beam output per unit area is reduced. By increasing the height and processing according to the procedure shown in Figure 3, as shown in Figure 2, seven well-ordered cylindrical ink passage holes 7 with a diameter of 10 μm and no molten material are formed in the position where the heating element is to be formed. was able to form. The processed substrate 10 is removed from the apparatus shown in FIG.
The groove machining and ink passage hole machining processes are completed. Next, after cleaning the substrate, 1 to 1
A SiO2 film 4 with a thickness of 10 μm is attached. This S
When the heating element substrate 10 is electrically conductive, the iO2 film 14 functions as an insulating layer thereof. 5i02 membrane 1
4, a resistive film 11 is formed by sputter-depositing, for example, Ta-3h02, etc. to a thickness of several thousand, and on top of this, a resistive film 11 is formed, for example, Ni.
A lead film 12 made of , Cr, Au, etc. is formed on a sheet or alone, and processed to form individual heating element groups and lead groups. Furthermore, in order to prevent oxidation and wear of the heating elements, for example, Wear-resistant protective film 13 made of 5i02 etc.
Then, the driving IC is connected to each lead, and the ink container 9 is bonded to the substrate 10, thereby producing a porous thermal head with 18 heating elements and an effective recording width of about 4 mm. done.

As is clear from the above manufacturing process, according to the method for manufacturing a porous thermal head of the present invention, first, processing can be performed on a ceramic heating element substrate. Secondly, since no melt or the like is generated in the step of forming ink passage holes, clear openings can be formed, and ink passage holes with a small aperture of any shape can be formed. Thirdly, there is no need for a drilling process for the 8+02 film 14, the resistive film 11, and the wear-resistant protective film 13. That is, when the manufacturing process of the present invention is used, the above-mentioned three films are not formed at the positions of the ink passage holes 7 of the substrate 10, and the process can be reduced.Fourthly, prior to the formation of the heating element Since the grooves and ink passage holes are processed, the manufacturing process can be separated and the process is simpler, making it easier to manage the manufacturing process.

When a recording experiment was conducted using this porous thermal head in the configuration shown in FIG. 12, good recorded images were obtained with no trailing or fogging.

In addition, in conventional porous thermal heads that use polyimide resin as a substrate, the substrate has poor heat resistance, so if the heating element 4 is energized (dry operation) without ink 9 in the ink container 8, the substrate will melt. However, there was a risk of damaging the porous thermal head.

However, in the porous thermal head of the present invention, the melting point of the substrate is very high (1000° C. or higher), and there is almost no risk of damage to the porous thermal head due to the dry firing operation. Moreover, when we measured the temperature change at the heating element by applying pulsed current to the heating element without ink in the porous thermal head of the present invention, the fall of the thermal pulse sufficiently followed the recording speed. I found out that it is possible. This is because, in the present invention, the heating element substrate is made of ceramic, which is a good thermal conductor, and the grooves and ink passage holes are formed in the desired shape, and can be manufactured satisfactorily using the manufacturing method of the present invention.

(Example 2) FIG. 4 is a sectional view of a second example of a porous thermal head manufactured according to the present invention, and FIG. 5 is a view similar to FIG. 2. The heating element substrate 10 in the figure is made of At203'TiC with a thickness of 0.7 mm, which is the same ceramic as in Example 1, and the thickness of the substrate 10 at the groove 15 is 100 μm1.
Three elongated holes of about 150 μm x 20 t1 m are formed in one heating element 11. By forming the elongated ink passage holes 7 and adjusting their intervals, there is an advantage that the temperature distribution within the heating element 11 can be adjusted and the leakage of heat to the adjacent heating element 11 can be adjusted. . With the configuration shown in FIG. 5, a good recording side without trailing or fogging was obtained.

(Embodiment 3) FIG. 6 is a diagram similar to FIG. 5 for explaining a third embodiment of the porous thermal head. The heating element substrate 10 uses <AI□03・TiC, which is the same as in the actual flow example. 200μm x 3
By forming three ink passage holes 7 in the form of elongated holes of 0 μm, the shape is such that four heating elements 11 are connected in parallel to one lead 12. In the head of this example,
When a recording experiment was conducted, good recorded images with no trailing or fogging were obtained as in Examples 1 and 2.

Grooves and ink passage holes were formed in the heating element substrate 10 using the following procedure. First, using an apparatus similar to that shown in FIG. 3, a mask is prepared in advance in which perforations having the same shape, pitch, and arrangement as the ink passage holes 7 shown in FIG. 6 are formed in a thin PZT plate. It is desirable that the material of this mask is a material whose processing speed is slower than that of the material of the heating element 10 of the porous thermal head.

From this point of view, PZT was selected as the material for the mask, but
As long as the thickness of the mask is thicker than the depth of the ink passage hole 7, a material for the mask that can be processed at the same speed as the mask may be used. Next, the heating element substrate 10 is processed. First, a thin plate of △1□03・TiC was polished to a thickness of 20μ.
The substrate is finished to a thickness of m, and grooves are processed using a processing apparatus having the basic configuration shown in FIG. 3 until the substrate thickness reaches 30 μm. Next, after alignment, the PZ described above is placed on the unprocessed surface of the groove of the substrate 10.
Adhere the T-mask with an adhesive (for example, trade name: Cerabond). It is also effective to cover the surface of the heating element substrate 10 with a chemically stable and opaque film instead of adhering the PZT mask. On the PZT mask side, a laser beam is irradiated and the XY stage 2 is
3 to scan the entire surface of the mask with a laser beam, ink passage holes 7 are formed in the heating element substrate 10 only in the perforated portions on the mask. The heating element substrate 10 is taken out from the etching solution, the adhesive is removed with a release agent, the heating element substrate 10 and the mask are separated, and the mask is washed. 11. After depositing the lead film 12, the individual heating elements and leads are processed, and the wear-resistant protective film 13 is deposited to complete head manufacture.

In this example, a PZT mask was used to manufacture the porous thermal head, but the advantage of this is that once the PZT mask is manufactured with high precision, a large number of porous thermal heads with the same precision can be manufactured with high efficiency. be. Also, the ink passage hole 7
In order to accurately and easily align the heating element at the position shown in FIG. It is also effective to form grooves or cross grooves to serve as alignment markers in the heating element substrate 10 using perforations on the mask.

(Embodiment 4) FIG. 7 is a sectional view of a fourth embodiment of the porous thermal head according to the present invention, in which TiC is used as the material of the substrate 10. FIG. 8 shows a plan view with the protective film 13 removed. In this way, the elongated ink passage hole 7 of 100 μm x 50 μm could be formed in the heating element 11.

The manufacturing process is as follows. First, after polishing the substrate 10 to a thickness of 30 μm, ink passage holes 7 are formed, and after attaching the SiO2 film 4, the resistive film 11, and the lead film 12, the individual heating elements and leads are processed. After that, a wear-resistant protective film 13 is attached, a drive IC is connected to each lead, and an ink container 8 is adhered to the wear-resistant protective film 13 side to complete a porous thermal head. According to this embodiment, the heating element faces the ink container side, that is, the ink side, and is characterized in that the recording energy is small. In addition to Figure 7,
It is also effective to adopt a structure in which grooves 15 are formed as shown in FIG.

In the method of manufacturing a porous thermal head of the present invention, the material of the heating element substrate 10 may be ceramics such as SiC, metals such as Ta, Fe, Ni, etc., or semiconductors such as $1, etc.
It can be used in addition to the ceramic materials shown above.

Furthermore, CF, SF6, etc. can be used as the reactive gas.

(Embodiment 5) FIG. 10 is a sectional view of a fifth embodiment of the present invention. The substrate 10 is a photosensitive material (eg, trade name: PEG-3, Photoceram, Photoform, etc.). In manufacturing, first, a groove 15 is formed on the substrate 10 by exposure to a thickness of 50 μm, and then the substrate 10 is exposed from the side opposite to the 7M15 to form a groove 15 with a diameter of 30 μm.
Ink passage holes 7 of .mu.m are formed by exposure and development processing is performed. Furthermore, S + 02 IJl 4, resistive film 11. After attaching the lead film 12, processing the individual heating element groups and lead groups, and attaching the abrasion resistant WIII 113, the drive IC is connected to each lead, and the ink container 8 is bonded to finish. When a recording experiment was conducted using the porous thermal head of this example, good image quality could be obtained as in the other examples.

(Effects of the Invention) As explained above, according to the first invention, since the substrate is made of a material with high rigidity and good heat conduction, the shape of the ink passage hole, which is a fine hole, is not deformed. It has the advantage that it is possible to obtain a good recording side without trailing, fogging, or scumming because the heating element has a good heat decay.

Further, according to the second invention, oxidation or corrosion of the heating element does not occur, fine ink passage holes are clearly formed at desired positions in the heating element, and the process is the shortest.
There is an advantage that a porous thermal head that can be used to obtain good image quality can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a porous thermal head showing a first embodiment of the present invention, and FIG. 2 is a cross-sectional view of a porous thermal head showing a first embodiment of the present invention. ! 3 is a schematic configuration diagram of the apparatus used in manufacturing the porous thermal head, FIG. 4 is a sectional view of the porous thermal head showing the second embodiment, and FIG. 5 is a bottom view with the membrane removed. FIG. 6 is a cross-sectional view of a porous thermal head showing the third embodiment; FIG. 7 is a cross-sectional view of the porous thermal head showing the fourth embodiment. , FIG. 8 is a plan view of the fourth embodiment with the protective film removed, and FIG. 9 is a plan view of the fourth embodiment.
10 is a sectional view of a porous thermal head showing the fifth embodiment, FIG. 11 is a basic configuration diagram of a thermal transfer recording method, and FIG. 12 is a diagram of a thermal transfer recording method. FIG. 13 is a basic configuration diagram of a porous thermal head. 7... Ink passage hole, 8... Ink container, 9...
Semi-solid ink, 10... Heating element substrate, 11... Resistance film, 12... Lead film, 13... Wear-resistant protective film, 1
4... Insulating film, 15... Groove, 16... Etching liquid storage tank, 17... Laser oscillator, 18... Semi-transparent mirror, 19... Convex lens, 20... Television motor, 2
1... Etched container, 22... Table, 2
3... XY stage, 24... Barrier pull valve, 25
... Branch pipe, 26... Etching liquid delivery pipe, 27.
... Pump, 28... Barrier pull valve, 29... Etching liquid supply pipe, 30... Etching liquid.

Claims (7)

[Claims] (1) A heating element substrate made of a material with high rigidity and good thermal conductivity, a large number of ink passage holes provided so as to pass through the grooves or plane parts of the substrate, and a substrate at least at the periphery of each of the ink passage holes. A porous thermal head comprising: an insulating film provided thereon, a resistive film, and a heating element formed of a lead film connected to the resistive film. (2) A porous thermal head according to claim 1, characterized in that ceramic is used as the heating element substrate. (3) A porous thermal head according to claim 1, characterized in that a photosensitive material is used as the heating element substrate. (4) forming grooves or flat surfaces on one side of a heating element substrate made of a material with high rigidity and good thermal conductivity, and forming an ink passage hole at a position where the heating element is formed on the heating element substrate; After forming an insulating film on one surface of the heating element substrate, attaching a resistive film and a lead film on the insulating film, and aligning with the ink passage holes, a heating element group and a lead group are formed. 1. A method for manufacturing a porous thermal head, comprising: a step of forming a wear-resistant protective film for protecting the heating element group. (5) In the groove machining, flat surface machining, or ink passage hole machining process for the heating element substrate, the heating element substrate is fixed in a chemical atmosphere, and the surface of the substrate is scanned with a laser beam to form grooves and flat surfaces of a predetermined shape. 5. The method of manufacturing a porous thermal head according to claim 4, further comprising forming ink passage holes. (6) In the groove, plane processing or ink passage hole processing process for the heating element substrate, on the surface of the heating element substrate,
a desired groove made of chemical, stable and opaque material;
A mask or film is coated with a plane or a pattern of ink passage holes, and then the heating element substrate is fixed in a chemical atmosphere, and a laser beam is irradiated and scanned from above,
5. The method of manufacturing a porous thermal head according to claim 4, wherein grooves, planes, or ink passage holes having a predetermined shape are formed. (7) A porous type thermal sensor according to claim 4, wherein a photosensitive material is used for the heating element substrate, and grooves, flat surfaces, or ink passage holes are formed on the heating element substrate by photolithography. Head manufacturing method.