JP5765004B2 - Thermal head and thermal printer - Google Patents

Description

  The present invention relates to a thermal head and a thermal printer.

  A thermal printer is known as one of printing apparatuses. The thermal printer has a thermal head in which heating elements are linearly arranged (see, for example, Patent Documents 1 and 2). The heating elements arranged in the thermal head selectively generate heat when energized. The thermal energy selectively reacts with the color former contained in the thermal paper, thereby printing various information on the thermal paper. This printing method is called a thermosensitive coloring method.

JP-A-9-39282 Japanese Patent Laid-Open No. 5-261957

  In a thermal printer having a thermal head as described in the above document, a printing medium such as thermal paper is sandwiched between a thermal head and a cylindrical member called a platen disposed opposite to the thermal head during printing. Then, the printing is performed while the printing medium is conveyed by rotating the platen around the axis. For this reason, in the area where the thermal head is in contact with the print medium, friction with the print medium always occurs and wears and deteriorates.

  In the conventional configuration, when such deterioration progresses, the wiring provided on the thermal head wears down and the current capacity decreases, so that the required power cannot be supplied to the heating element, or the power is disconnected and energized. There was a risk of disappearing. Therefore, thermal printers are difficult to ensure printing reliability when used over a long period of time, and there has been a demand for longer life of components.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a thermal head whose performance is not easily lowered even when used over a long period of time. Another object of the present invention is to provide a thermal printer with high reliability by having such a thermal head.

In order to solve the above problems, a thermal head of the present invention includes a substrate and a plurality of heating elements provided along an array axis set on the substrate, and the heating element is a heating resistor. And an individual electrode and a common electrode connected to the heating resistor, wherein the common electrode is connected to a common wiring disposed around the plurality of heating elements, and the common wiring is at least the In a region intersecting with the arrangement axis, it extends from the upper surface of the substrate to reach the surface of the side surface of the substrate, and a part of the common wiring that is provided on the surface of the side surface, It has the protrusion part which protruded from the said side surface in planar view, It is characterized by the above-mentioned.
In order to solve the above problems, a thermal head of the present invention includes a substrate and a plurality of heating elements provided along an array axis set on the substrate, and the heating element is a heating resistor. And an individual electrode and a common electrode connected to the heating resistor, wherein the common electrode is connected to a common wiring disposed around the plurality of heating elements, and the common wiring is at least the In the region intersecting with the arrangement axis, there is a protrusion provided to extend to the side surface of the substrate.
According to this configuration, since the common wiring extends to the side surface of the substrate at the protruding portion, the thickness of the common wiring (height in the normal direction of the substrate) decreases due to friction with the print medium. However, it is easy to ensure conduction, and a decrease in current capacity of the common wiring can be suppressed. Therefore, it is possible to provide a thermal head whose performance is hardly deteriorated even when used for a long time.

In the present invention, the substrate includes a base and a planarization layer provided on one main surface of the base and including silicon oxide or silicon nitride as a forming material, and the protruding portion is the planarization. A first wiring layer provided at least in part on the layer, and a second wiring layer formed on the first wiring layer so as not to contact the planarization layer and made of silver. It is desirable to have.
According to this configuration, the current capacity of the common wiring can be effectively increased, and deterioration of the second wiring layer caused by contact between silver and the silicon compound can be suppressed. Therefore, a highly reliable thermal head can be obtained.

In the present invention, the first wiring layer is preferably made of gold.
According to this configuration, it is possible to obtain a common wiring that effectively increases the current capacity and suppresses the deterioration of the second wiring layer.

A thermal printer according to the present invention includes the above-described thermal head, a platen provided opposite to the thermal head, sandwiching a heat-sensitive printing medium between the thermal head and conveying the printing medium, It is characterized by having.
According to this configuration, since the above-described thermal head is provided, the reliability is high.

It is explanatory drawing which shows the thermal printer of this embodiment. FIG. 3 is an enlarged view of a printing unit included in a printer mechanism unit. It is an external appearance perspective view of a thermal head. It is a top view of the head substrate of a thermal head. It is arrow sectional drawing of a thermal head.

  Hereinafter, the thermal head of the present embodiment and a thermal printer including the thermal head will be described with reference to FIGS. In all the drawings below, the dimensions and ratios of the constituent elements are appropriately changed in order to make the drawings easy to see.

  FIG. 1 is an explanatory diagram showing a thermal printer 100 according to the present embodiment, and is a side sectional view showing a side section of a printer mechanism unit 300 that is a main part of the thermal printer 100. FIG. 2 is an enlarged view of the printing unit 70 included in the printer mechanism unit 300.

  As shown in FIG. 1, the printer mechanism unit 300 is provided with a main body frame 60 that accommodates roll paper R, a cover frame 10, a roll paper holder 30, and the thermal head 1 of the present invention, and is pulled out from the roll paper holder 30. A printing unit 70 that prints on the thermal paper S, and a paper cutting unit 20 that is provided behind the printing unit 70 in the paper feed direction and cuts the printed thermal paper S for each predetermined printing unit.

The thermal paper S has a printing surface composed of a coloring layer in which a coloring agent is held by a binder or the like. In the thermal printer 100, the thermal paper S is stored inside as a roll paper R wound up in a roll shape with the printing surface as an outer surface, and is sent to the printing unit 70 (thermal head 1) and printed while being sequentially drawn out. The
Hereinafter, each configuration of the printer mechanism unit 300 will be described along the paper feeding direction of the thermal paper S.

  The main body frame 60 is formed in a box shape having an opening on the upper side, and the cover frame 10 is provided above the main body frame 60 so as to cover the opening of the main body frame 60. A roll paper holder 30 is provided inside the main body frame 60.

  The cover frame 10 is attached so as to be openable and closable around a support shaft 68 provided at one end portion above the main body frame 60. The cover frame 10 is provided with an arcuate lid portion 15 for avoiding contact with the roll paper R when the cover frame 10 is closed. The lid 15 also functions as a holding member that receives the roll paper R when the installation angle of the thermal printer 100 is changed, that is, for example, when the thermal printer 100 is placed vertically.

  The roll paper holder 30 is formed of resin or the like. The roll paper holder 30 has a substantially arc-shaped depression corresponding to the maximum diameter of the roll paper R at the center, and is attached to the bottom of the main body frame 60 so that the substantially arc-shaped depression protrudes downward. It has been.

  When the roll paper R is arranged in the roll paper holder 30 provided in this way, the roll paper holder 30 holds the roll paper R in a rotatable manner. At the same time, both side surfaces on the inner side of the main body frame 60 function as side surface guide portions of the roll paper R to restrict the movement of the roll paper R in the width direction.

  As shown in FIG. 2, the printing unit 70 holds the thermal head 1, a platen 71 provided so as to be opposed to the thermal head 1 and in which the thermal paper 1 is in close contact with the thermal head 1, and the thermal head 1. And a head holding mechanism 77 that biases 1 toward the platen 71.

  The thermal head 1 includes a head substrate (substrate) 110 provided with a plurality of heating elements for printing on the thermal paper S, and a heat radiating plate 106 that is provided in close contact with the head substrate 110 and radiates heat accumulated in the head substrate 110. And a head support shaft 102 provided on the side surface of the heat radiating plate 106 and an FPC 108 connected to the head substrate 110 for inputting signals. Details of the thermal head 1 will be described later.

  The platen 71 is formed in a cylindrical roller shape by an elastic member such as rubber and is rotatably supported by the cover frame 10 via a platen bearing 73. Further, a paper feed mechanism (not shown) for rotating the platen 71 is provided on the side surface of the main body frame 60. The paper feed mechanism (not shown) is connected to the platen bearing 73 in a state where the cover frame 10 is closed. Drive to rotate. Thus, when the platen 71 rotates, the thermal paper S is transported downstream of the transport path D.

  The head holding mechanism 77 includes a head pressing plate 72 and a spring 75 having one end fixed to the head pressing plate 72 and the other end contacting the back surface of the thermal head 1. The cutout portion 62 is detachably provided.

  The spring 75 fixed to the head pressing plate 72 is in contact with the back surface of the thermal head 1 and biases the thermal head 1 toward the platen 71. Thereby, the thermal head 1 presses the thermal paper S in the direction of the platen 71 from the printing surface S1 side. On the other hand, the platen 71 presses the thermal paper S in the direction of the thermal head 1 from the back surface S2. As a result, the thermal paper S is sandwiched between the thermal head 1 and the platen 71. The thermal paper S is printed by the thermal head 1, and the printed thermal paper S is transported downstream of the transport path D as the platen 71 rotates.

Returning to FIG. 1, the paper cutting unit 20 includes a movable blade 21, a fixed blade 24 provided to face the movable blade 21, and a fixed blade cover 25 that covers the fixed blade 24. It is provided at the paper exit G through which the thermal paper S after printing passes. In the paper cutting part 20, the thermal paper S is cut | disconnected by the movable blade 21 and the fixed blade 24 crossing in scissors shape.
The thermal printer 100 of the present embodiment has the schematic configuration as described above.

(Thermal head)
Next, the thermal head 1 will be described with reference to FIGS. FIG. 3 is an external perspective view of the thermal head. FIG. 4 is a plan view of the head substrate of the thermal head, FIG. 4 (a) is an overall view of the head substrate, and FIG. 4 (b) is a partially enlarged view of FIG. 4 (a). FIG. 5 is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 3, the thermal head 1 includes a head substrate 110, a heat radiating plate 106, a head support shaft 102, a driver IC 120, and an FPC 108.

  The head substrate 110 has a long rectangular shape in plan view. A plurality of heating elements 145 are formed on one main surface of the head substrate 110 on one end side in the short direction, and the plurality of heating elements 145 are arranged in the longitudinal direction of the head substrate 110 to form a heating element array. 145a is formed. A plurality of driver ICs 120 for driving the heat generating elements 145 are arranged in parallel with the heat generating element rows 145a.

  The heat sink 106 is formed by drawing a metal material such as aluminum, and the head substrate 110 is fixed to the locking surface 106 a of the heat sink 106. As a fixing method of the head substrate 110, for example, a method such as sticking using a double-sided tape can be employed.

  In the heat radiating plate 106, a guide slope portion 104 is formed at the end of the head substrate 110 on the side where the heat generating element array 145 a is provided over the longitudinal direction of the heat radiating plate 106. When the cover slope 10 shown in FIG. 1 is closed, the guide slope portion 104 slides the platen 71 to guide it to a predetermined position. At this time, the inclination of the guide slope portion 104 has a predetermined angle so that the platen 71 does not collide with the head substrate 110. Further, the end of the guide slope portion 104 on the head substrate 110 side is set so that the height of the locking surface 106a in the normal direction is substantially the same as the height of the head substrate 110 attached to the locking surface 106a. Has been.

  The head support shaft 102 is a cylindrical round pin, and is press-fitted into holes provided in the left and right side portions of the heat radiating plate 106.

(Head substrate)
As shown in FIG. 4A, the head substrate 110 has a belt-like heating element (heating resistor) 140 in the longitudinal direction along the edge (one side edge 110a) on the guide slope portion 104 side in FIG. Is provided.

  The other side edge 110b of the head substrate 110 is provided with a plurality of external connection terminals 112 for electrical connection with the outside. Further, a strip-shaped common wiring pattern (common wiring) 114 is formed in a frame shape on the peripheral edge of the head substrate 110, and both ends of the common wiring pattern 114 are connected to the external connection terminals 112 at the other side edge 110b. It is connected. Further, the common wiring pattern 114 is provided so as to overlap with the end of the heating element 140.

  In the approximate center of the head substrate 110, an IC mounting portion 120a for mounting the driver IC 120 is disposed in parallel with the belt-like heating element 140 for each driver IC 120.

  As shown in FIG. 4B, a plurality of comb-like common electrodes 114 a extending in the center direction of the surface of the head substrate 110 are formed from the common wiring pattern 114. The common electrode 114 a is provided so as to intersect with the belt-like heating element 140.

  A plurality of individual electrodes 118 are provided at the center of the head substrate 110. Each individual electrode 118 is provided so as to intersect with the belt-like heating element 140 so that one end thereof enters between the comb-like common electrodes 114a. The other end portion of each individual electrode 118 extends to an IC mounting portion 120a provided on the head substrate 110, and an electrode pad 115 as a mounting terminal is formed at the end portion.

  On the other hand, an electrode pad 116 as a mounting terminal is formed on the other side edge 110b side of the head substrate 110 of the IC mounting portion 120a. The electrode pad 116 is electrically connected to the external connection terminal 112 shown in FIG.

  The FPC 108 shown in FIG. 3 is attached to the external connection terminal 112, and is connected to a main circuit board (not shown) constituting a control unit that controls the thermal printer 100 via the FPC 108. Further, the driver IC 120 shown in FIG. 3 is mounted on the electrode pad 115 and the electrode pad 116, and an input signal such as print data, a drive current, and the like are input from a control unit of a thermal printer (not shown).

  The comb-like common electrodes 114a and individual electrodes 118 that are alternately arranged adjacent to each other and the heating element 140 that is partitioned by the common electrodes 114a and the individual electrodes 118 define a heating element 145. That is, when the selected individual electrode 118 is turned on by the driver IC 120, a current flows through the heating element 140 in a region surrounded by the individual electrode 118 and the comb-like common electrode 114a, and that portion is the heating element 145. Function as. The heating element 145 defined as described above is arranged along the extending direction of the heating element 140 with the belt-like heating element 140 as an array axis.

  As shown in FIG. 4B, the common wiring pattern 114 of the thermal head 1 protrudes from the side surface 110c of the head substrate 110 in a plan view in a portion overlapping the area AR where the platen 71 and the thermal head 1 are in contact. The protruding portion 114x is formed.

  FIG. 5 is a cross-sectional view of the thermal head 1 and includes a protrusion 114x. The thermal head 1 includes a head substrate 110, a common electrode 114 a and individual electrodes 118, a common wiring pattern 114, a heating element 140, a first protective film 170, and a second protective film 180.

  The head substrate 110 includes a base 110x formed using a ceramic material such as alumina ceramic, and a planarization layer 110y provided on one main surface of the base 110x. The planarization layer 110y is provided to planarize the surface unevenness of the base 110x. The planarization layer 110y is formed using silicon oxide or silicon nitride (an inorganic silicon compound such as silicon oxide, silicon oxynitride, or silicon nitride).

  On the planarization layer 110y, the common electrode 114a and the individual electrode 118, and the heating element 140 provided to overlap the common electrode 114a, the individual electrode 118, and the common wiring pattern 114 are provided. Further, a common wiring pattern 114 is provided so as to extend from the end of the upper surface of the planarizing layer 110y to the side surface of the base 110x.

  The common wiring pattern 114 is provided on the first wiring layer 150 and the first wiring layer 150 provided to extend from the end of the upper surface of the planarizing layer 110y to the end of the base 110x. And a second wiring layer 160 provided to extend from the end of the upper surface of 110y to the side surface of the base 110x (side surface 110c of the head substrate 110).

  The first wiring layer 150 is made of gold (Au) as a forming material, and is provided in the same layer as the common electrode 114 a and the individual electrode 118.

  The second wiring layer 160 has a function of decreasing the resistance value of the entire common wiring pattern 114 by being stacked on the first wiring layer 150. Silver (Ag) is used as a material for forming the second wiring layer 160.

  Further, since the common wiring pattern 114 has such a laminated structure, the heat capacity is increased as compared with the conventional structure. For this reason, the common wiring pattern 114 stores heat generated in the heat generating element 145, and the effect of assisting the temperature increase of the heat generating element 145 can be expected.

  That is, in the thermal head 1, when the energization of the heat generating element 145 is switched to the resting state, the heat generation of the heat generating element 145 is stopped, and the heat remaining in the heat generating element 145 is quickly radiated to the heat radiating plate 106. However, if the thermal head 1 is provided with a wiring having a large heat capacity, such as the common wiring pattern 114 of the present embodiment, heat can be stored around the heating element 145 that is not in the printing region. The heat storage can be used to assist heating during heating.

  The first protective film 170 and the second protective film 180 are both inorganic films, and have a function of protecting structures such as the common wiring pattern 114 and the heating element 140 from damage due to friction with the thermal paper S. ing. In order to suppress frictional charging with the thermal paper S, the first protective film 170 and the second protective film 180 may be provided with conductivity by adding a conductive material, and the charge may be removed.

  In the thermal head 1 having such a configuration, it is possible to obtain an effect that the performance of the common wiring pattern 114 is hardly deteriorated even when used for a long time.

  Conventionally, the common wiring pattern 114 has a two-layer structure of a first wiring layer 150 and a second wiring layer 160. Therefore, as shown in FIG. 5, the portion where the common wiring pattern 114 is provided protrudes in the normal direction on the upper surface of the head substrate 110 from the portion where the other common electrode 114a and the individual electrode 118 are provided.

  Therefore, when printing while sandwiching the thermal paper S between the thermal head 1 and the platen 71, the common wiring pattern 114 is in a region where the platen 71 and the thermal head 1 are in contact (region AR in FIG. 4B). A higher pressure is applied to the portion overlapping with the other portions. Therefore, in the portion overlapping the common wiring pattern 114, damage due to friction with the thermal paper S at the time of printing is more severe than in other portions, and the common wiring pattern 114 may be disconnected when the damage progresses.

  Furthermore, when manufacturing the platen 71, the surface of the platen 71 is trimmed to make the cross section of the platen 71 substantially circular. However, since the platen 71 is formed using an elastic material, the shape is adjusted. The later platen 71 is wound in a bobbin shape, that is, the end of the platen 71 tends to have a larger radius. When the platen 71 having such a shape is used, damage to the portion overlapping the common wiring pattern 114 is likely to be more severe.

  However, in the thermal head 1 of the present embodiment, the second wiring layer 160 of the common wiring pattern 114 is formed so as to extend to the side surface 110c of the head substrate 110 at the protruding portion 114x. Therefore, even if the common wiring pattern 114 is further damaged due to friction with the thermal paper S, conduction is ensured and the current capacity of the common wiring pattern 114 is unlikely to decrease.

  In addition, when silver, which is a forming material of the second wiring layer 160, comes into contact with an inorganic silicon compound, which is a forming material of the planarization layer 110y, the interface deteriorates and is easily peeled off at the interface. However, in the present embodiment, the first wiring layer 150 is provided between the planarization layer 110y and the second wiring layer 160, and is separated from the planarization layer 110y and the second wiring layer 160 so as not to contact each other. Therefore, the occurrence of such a problem can be suppressed.

  Therefore, even if the thermal head 1 having the above-described configuration is used for a long period of time, the current capacity of the common wiring pattern 114 is not easily lowered, and the reliability is improved.

  Further, since the thermal printer 100 having the above-described configuration includes the thermal head 1 described above, it has high reliability.

  In the present embodiment, at least the protrusion 114x has the first wiring layer 150 and the second wiring layer 160. However, the common wiring pattern 114 may be worn even if only one layer is formed. The effect which suppresses the performance fall by is obtained.

  In the present embodiment, the protruding portion 114x is provided in part on the side surface 110c. However, the protruding portion 114x may be provided over the entire side surface 110c.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Thermal head, 71 ... Platen, 100 ... Thermal printer, 110 ... Head board | substrate (board | substrate), 110x ... Base | substrate, 110y ... Planarization layer, 114 ... Common wiring pattern (common wiring), 114a ... Common electrode, 114x ... Projection 118, individual electrodes, 140, heating element (heating resistor, array axis), 145, heating element, 150, first wiring layer, 160, second wiring layer, S, thermal paper (printing medium)

Claims (6)

A substrate,
A plurality of heating elements provided along an array axis set on the substrate,
The heating element has a heating resistor, and an individual electrode and a common electrode connected to the heating resistor,
The common electrode is connected to a common wiring disposed around the plurality of heating elements,
The common wiring is at least Oite in cross areas of said array axis, it provided extending from the upper surface of the substrate to reach the surface side of the substrate, and the side a part of the common wiring A thermal head characterized in that a portion provided on the surface has a protruding portion protruding from the side surface in plan view . The substrate includes a base and a planarization layer provided on one main surface of the base and including silicon oxide or silicon nitride as a forming material,
The portion where the common wiring is provided protrudes in the normal direction of the upper surface of the substrate from the portion where the common electrode and the individual electrode are provided,
The protruding portion includes a first wiring layer provided at least in part on the planarizing layer;
The provided so as not to contact the planarization layer, it possesses a second wiring layer to silver forming material, the in on the first wiring layer,
The second wiring layer overlaps with an end of the upper surface of the planarization layer in a plan view;
2. The thermal head according to claim 1, wherein the second wiring layer is formed so as to extend from an upper surface of the substrate to a side surface of the substrate .   The thermal head according to claim 2, wherein the first wiring layer is made of gold.   4. The thermal head according to claim 1, further comprising a protective film that uses an inorganic material as a forming material and covers the plurality of heating elements and the common wiring. 5.   The thermal head according to claim 4, wherein a conductive material is added to the protective film. The thermal head according to any one of claims 1 to 5 ,
A thermal printer comprising: a platen that is provided opposite to the thermal head and sandwiches a heat-sensitive printing medium between the thermal head and conveys the printing medium.

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