JP4565724B2 - Thermal printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermal printer that performs thermal recording on a recording medium such as thermal paper using a thermal head.
[0002]
[Prior art]
In the conventional thermal printer, for example, as shown in FIG. 3, a glaze layer 13 having a mountain-like cross section having a convex portion 13 a at the top is deposited on the upper surface of the substrate 12, and heat is generated on the convex portion 13 a of the glaze layer 13. A thermal head 11 in which a resistor 14 is disposed and covered with a protective film 15, and a cylindrical shape that is disposed on the thermal head 11 and presses a recording medium such as thermal paper against the convex portion 13 a of the glaze layer 13. The platen roller 16 is provided, and while the recording medium is conveyed onto the thermal head 11 by the platen roller 16, the heating resistor 14 of the thermal head 11 is selectively Joule-heated based on the image data. The generated heat is conducted to the recording medium to form a predetermined print on the recording medium, thereby functioning as a thermal printer.
[0003]
The glaze layer 13 of the thermal head 11 is formed of a low thermal conductivity material such as glass, and the thermal response of the thermal head 11 is accumulated and dissipated in part of the heat generated by the heating resistor 14. Good characteristics are maintained.
[0004]
Further, the convex portion 13a of the glaze layer 13 is for effectively increasing the pressing force of the recording medium against the heating resistor 14 during printing. When the convex portion 13a is formed, first, a “smooth” cross section is formed. An arc-shaped glaze layer is formed by applying and baking a glass paste, and then a portion of the glaze layer surface except the top is etched away to a predetermined depth, leaving a substantially trapezoidal convex portion 13a on the top. For example, it was formed in the thickness of 2 micrometers-4 micrometers.
[0005]
[Problems to be solved by the invention]
However, in the conventional thermal printer described above, the heating resistor 14 of the thermal head 11 is provided on the convex portion 13a of the glaze layer 13, and the pressing force from the platen roller 16 is concentrated near the convex portion 13a. It has become. For this reason, if the height of the convex portion 13a varies due to the processing accuracy of the glaze layer 13, the pressing force of the platen roller 16 against the thermal head 11 becomes non-uniform. Disadvantages such as “sticking” that is conveyed while being caught causes printing to become unclear, or that the recording medium is conveyed in a state of being strongly pressed against the thermal head 11 to generate large noise. Had.
[0006]
Therefore, in order to eliminate such drawbacks, it is conceivable to finely adjust the mounting position of the platen roller 16 in the vertical direction to optimize the pressing force of the platen roller 16 against the thermal head 11. The adjustment work requires a lot of labor and labor, leading to a drawback that the productivity of the thermal printer is significantly reduced.
[0007]
The present invention has been devised in view of the above drawbacks, and its purpose is to be able to form a clear print on a recording medium, and to reduce the noise associated with the conveyance of the recording medium. The object is to provide an excellent thermal printer.
[0008]
[Means for Solving the Problems]
Thermal printer of the present invention, the upper surface of the substrate, the cross-sectional mountain shape of the glaze layer having a convex portion at the top along with the depositing, by attaching the heating resistor to the glaze layer, the on the convex portion arranged a heating resistor, a thermal head formed by connecting a pair of electrodes to the heating resistor at a position sandwiching the convex portion, is disposed on the thermal head, the convex portion of the recording medium said glaze layer in platen Toka Ranaru thermal printer that presses a, the upper surface of the heating resistor positioned on the convex portion, with which also is protruded upward from an end portion of the pair of electrodes facing each other across the protruding portion , the upper surface of the glaze layer having the convex portion, and on both sides of the convex portion to form a pair of ridges is raised the portion of the glaze layer, the pressing force of the platen with respect to the glaze layer Convex It is characterized in that no to apply by dispersing fine pair of ridges.
[0011]
According to the thermal printer of the present invention, a pair of raised portions in which a part of the glaze layer is raised on the upper surface of the glaze layer provided on the substrate of the thermal head and on both sides of the convex portion on which the heating resistor is disposed. Since the pressing force from the platen is distributed and applied to the three portions of the convex portion and the pair of raised portions, the platen is favorably supported on both sides of the convex portion by the pair of raised portions. Even if the height of the convex portion varies due to the processing accuracy of the glaze layer, an appropriate pressing force is applied to the convex portion regardless of the height of the convex portion. Will be able to. Therefore, the recording medium is always stably conveyed on the thermal head at the time of printing, and it becomes possible to form a clear image on the recording medium while effectively suppressing the occurrence of sticking and large printing noise.
[0012]
In addition, according to the thermal printer of the present invention, the above-mentioned appropriate pressing force can be obtained without finely adjusting the mounting position of the platen in the vertical direction. There is also an advantage that the productivity of the printer can be improved.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an exploded perspective view showing a configuration of a thermal printer according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the thermal printer of FIG. 1, 1 is a thermal head, and 7 is a platen roller (platen). is there.
[0014]
The thermal head 1 has a structure in which a glaze layer 3 having a mountain-like cross section is deposited in a strip shape on an upper surface of a rectangular substrate 2 and a number of heating resistors 4 are mounted on the glaze layer 3. Have.
[0015]
The substrate 2 is made of an electrically insulating material such as alumina ceramics, and functions as a support base material for supporting the glaze layer 3, a large number of heating resistors 4, electrodes 5, a protective film 6, and the like on its upper surface.
[0016]
When the substrate 2 is made of alumina ceramics, an appropriate organic solvent and solvent are added to and mixed with ceramic raw material powders such as alumina, silica, and magnesia to form a slurry, and this is made into a conventionally known doctor blade method or calender roll. A ceramic green sheet is obtained by adopting a method or the like, and then the ceramic green sheet is punched into a predetermined shape and then fired at a high temperature.
[0017]
Further, the glaze layer 3 provided on the upper surface of the substrate 2 is formed so as to have a mountain-shaped cross section with a low thermal conductivity material such as glass, and a convex portion 3a is formed on the top thereof, and the sub-scanning direction of the convex portion 3a is formed. A pair of raised portions 3b, 3b are provided on both sides in the direction (perpendicular to the arrangement direction of the heating resistors 4) at substantially the same height as the convex portions 3a.
[0018]
The convex portion 3a of the glaze layer 3 is formed to have a width of 50 μm to 200 μm and a thickness of 2 μm to 4 μm, for example, by raising a part of the glaze layer 3, and the heating resistor 4 is formed on the convex portion 3a. Is provided, and the heating resistor 4 is projected upward by the convex portion 3a.
[0019]
The glaze layer 3 effectively increases the pressing force against the recording medium by protruding the heating resistor 4 upward, and stores and dissipates a part of the heat generated by the heating resistor 4 in the thermal head. The heat response characteristic of 1 is maintained well.
[0020]
Further, the pair of raised portions 3b, 3b provided on both sides of the convex portion 3a has a height substantially equal to the convex portion 3a described above by raising a part of the glaze layer 3 by 2 μm to 4 μm. For example, when the platen roller 7 is disposed on the thermal head 1, the pressing force of the platen roller 7 is placed at a position separated from the edge of the portion 3 a by, for example, 30 μm to 500 μm. When applied, the platen roller 7 is supported together with the convex portion 3a.
[0021]
The glaze layer 3 is formed by first printing a predetermined glass paste obtained by adding and mixing an appropriate organic solvent to glass powder in a band shape with a thickness of 30 to 200 μm on the upper surface of the substrate 2 by screen printing or the like. -A glass layer having an arc-shaped cross section is formed by applying and baking at a high temperature, and then a part of the surface of the obtained glass layer is etched to a predetermined depth, for example, a region having a depth of 2 μm to 4 μm. It is formed by removing and leaving the convex portion 3a and the raised portion 3b at a predetermined position.
[0022]
The heating resistors 4 arranged on the convex portions 3a of the glaze layer 3 are arranged in a straight line in the main scanning direction at a density of, for example, 300 dpi (dot per inch). 4 is made of an electric resistance material such as TaSiO, TiSiO, TiCSiO, etc., so that when power is applied through the electrodes 5 connected to both ends, Joule heat is generated, and print dots are formed on the recording medium. It becomes a predetermined temperature necessary for this, for example, a temperature of 150 ° C. to 300 ° C.
[0023]
Such a heating resistor 4 and electrode 5 are deposited and formed to form a predetermined thickness and a predetermined pattern by employing a conventionally well-known thin film forming technique, for example, a sputtering method, a photolithography technique, an etching technique or the like. .
[0024]
Further, a protective film 6 is deposited on the upper surface of the heating resistor 4 and the electrode 5, and the surface of the heating resistor 4 and the electrode 5 is covered with the protective film 6.
[0025]
The protective film 6 is formed of an inorganic material such as silicon nitride or silicon carbide, and the heating resistor 4 and the electrode 5 are worn by sliding contact with a recording medium or corroded by contact with moisture contained in the atmosphere. It works to protect against.
[0026]
The protective film 6 is formed on the upper surface of the heating resistor 4 or the like by applying the above-described inorganic material to a thickness of 3 μm to 13 μm, for example, using a well-known thin film forming technique such as sputtering or vacuum deposition. Is done.
[0027]
The protective film 6 obtained in this way has a substantially constant thickness and a surface shape corresponding to the base, so that the platen roller 7 is formed on the convex portions 3a and the raised portions 3b, 3b of the glaze layer 3. The shape protrudes to the side.
[0028]
A platen roller 7 is disposed on the thermal head 1 described above.
The platen roller 7 is formed, for example, by winding butadiene rubber or the like around a rotating shaft 8 made of SUS or the like and forming a cylindrical shape, and is attached so that the rotating shaft 8 is positioned directly above the heating resistor 4.
[0029]
The platen roller 7 has a pressing force of 10 N / cm to 50 N / cm against the surface of the thermal head 1, specifically, the surface of the protective film 6 located on the convex portion 3 a and the raised portions 3 b and 3 b described above. The recording medium is sequentially fed between the roller 7 and the thermal head 1 while the platen roller 7 is rotated by a motor (not shown) or the like, so that the recording medium becomes the thermal head 1. It is conveyed in the sub-scanning direction while being pressed against the surface.
[0030]
Since the pressing force of the platen roller 7 is applied in a distributed manner at three locations of the convex portion 3a of the glaze layer 3 and a pair of raised portions 3b, 3b arranged on both sides thereof, The platen roller 7 is satisfactorily supported on both sides of the convex portion 3a by the pair of raised portions 3b, 3b, and the height of the convex portion 3a is increased due to the processing accuracy of the glaze layer 3 when the thermal head 1 is manufactured. Even if the variation occurs, an appropriate pressing force can be applied to the convex portion 3a regardless of the height. Therefore, the recording medium is always stably conveyed on the thermal head 1, and it becomes possible to form a clear image on the recording medium while effectively suppressing the occurrence of sticking and large printing noise.
[0031]
In addition, in this case, since the above-mentioned appropriate pressing force can be obtained without finely adjusting the mounting position of the platen roller 7 up and down, the assembly operation of the thermal printer becomes relatively simple, and the productivity of the thermal printer is increased. It can also be used for improvement.
[0032]
Thus, in the thermal printer of the present embodiment described above, while the recording medium is conveyed onto the heating resistor 4 of the thermal head 1 by the platen roller 7, the heating resistor 4 is selectively and selectively heated based on the image data. The generated heat is conducted to a recording medium pressed by the protective film 6 on the heating resistor 4 to form a predetermined print on the recording medium, thereby functioning as a thermal printer.
[0033]
In addition, this invention is not limited to the above-mentioned form, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention.
[0034]
For example, in the above-described embodiment, the convex portion 3a of the glaze layer 3 is arranged at the center of the pair of raised portions 3b, 3b. Instead, the convex portion 3a is arranged close to one of the raised portions 3a. It doesn't matter if you do.
[0035]
【The invention's effect】
According to the thermal printer of the present invention, a pair of raised portions in which a part of the glaze layer is raised on the upper surface of the glaze layer provided on the substrate of the thermal head and on both sides of the convex portion on which the heating resistor is disposed. Since the pressing force from the platen is distributed and applied to the three portions of the convex portion and the pair of raised portions, the platen is favorably supported on both sides of the convex portion by the pair of raised portions. Even if the height of the convex portion varies due to the processing accuracy of the glaze layer, an appropriate pressing force is applied to the convex portion regardless of the height of the convex portion. Will be able to. Therefore, the recording medium is always stably conveyed on the thermal head at the time of printing, and it becomes possible to form a clear image on the recording medium while effectively suppressing the occurrence of sticking and large printing noise.
[0036]
In addition, according to the thermal printer of the present invention, the above-mentioned appropriate pressing force can be obtained without finely adjusting the mounting position of the platen in the vertical direction. There is also an advantage that the productivity of the printer can be improved.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view illustrating a configuration of a thermal printer according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the thermal printer of FIG.
FIG. 3 is a cross-sectional view showing a configuration of a conventional thermal printer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Thermal head, 2 ... Board | substrate, 3 ... Glaze layer, 3a ... Convex part, 3b ... Raised part, 4 ... Heat generating resistor, 6 ... Protective film, 7 ... Platen (platen roller)

Claims (1)

A glaze layer having a mountain-shaped cross section having a convex portion at the top is deposited on the upper surface of the substrate, and a heating resistor is attached on the glaze layer, and the heating resistor is disposed on the convex portion. A thermal head formed by connecting a pair of electrodes to the heating resistor at a position sandwiching the convex portion;
In a thermal printer comprising a platen disposed on the thermal head and pressing a recording medium against the convex portion of the glaze layer,
The upper surface of the heating resistor located on the convex portion protrudes upward from the ends of the pair of electrodes facing each other across the convex portion, and
A pair of raised portions formed by raising a part of the glaze layer is formed on the upper surface of the glaze layer having the convex portion and on both sides of the convex portion, and the upper surface of the convex portion and the pair of raised portions And the upper surface of the plate is formed along the same circular arc in a cross-sectional view, and the pressing force of the platen against the glaze layer is distributed and applied to the convex portion and the pair of raised portions. Printer.

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