JP2009274410A - Thermal head and thermal transfer printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal head capable of achieving highly accurate temperature detection with no influence on a printing speed, and to provide a thermal transfer printer equipped with the thermal head. <P>SOLUTION: The thermal head 4 includes: a plurality of heat generating elements 29 arrayed in a predetermined direction; and a plurality of thermal-sensitive elements 30 arrayed between the heat generating elements 29, and also, arrayed together with the heat generating elements 29 at both the ends of the array. The width of the heat generating element 29 in the arraying direction is ≤1/3 of the array pitch-width of the heat generating elements 29. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thermal head having an element for detecting temperature, and a thermal transfer printer provided with the thermal head.

  In a general thermal transfer printer, a heat generating element of a thermal head is pressed against an ink sheet brought into contact with the recording paper, and the heat generating element generates heat to melt or sublimate the ink on the ink sheet and transfer it to the recording paper. Information such as images and characters. The amount of ink transferred to the recording paper is large when the temperature of the heating element is high, and is small when the temperature is low.

  Since it is necessary to transfer the desired amount of ink to the paper in order to obtain high-quality printed matter, a thermal element such as a thermistor is placed near the heating element, and the amount of heat generated by the heating element based on the measured value of the thermal element Is controlling. Although it is desirable to place the thermal element and the heating element closely in order to perform high-precision control, the thermal element is placed at a predetermined distance from the heating element to avoid contact with the ink sheet and recording paper. Has been. Therefore, there is a difference between the measured value of the heating element and the measured value of the thermal element, and the temperature response is delayed according to the heat capacity of the member between the temperature sensors of the heating element and the thermal element, thereby achieving high accuracy. There was a problem that control was impossible.

  As countermeasures against this problem, there are a heat-sensitive element formed on a heat-generating element (for example, see Patent Document 1) and a heat-generating element itself used as a heat-sensitive element (for example, see Patent Document 2).

JP 2007-301722 A Japanese Patent No. 3567241

  In Patent Document 1, since the heat sensitive element is formed on the heat generating element, there is a problem that the thermal resistance between the heat generating element and the ink sheet is increased by the heat sensitive element and the thermal efficiency is lowered. In addition, since the insulating film protective layer, the thermal element, the wiring electrode of the thermal element, and the protective layer are sequentially laminated on the formed heating element, there is a problem that the manufacturing process increases.

  In Patent Document 2, since the heat generating element itself is also used as a heat sensitive element, control is performed for switching between an operation of generating heat by printing the heat generating element and an operation of detecting temperature without generating heat by the heat generating element. Takes a long time to affect the printing speed. In addition, since the ratio of the time during which heat generation can be controlled with respect to the printing time decreases, the control accuracy also decreases. Furthermore, since temperature measurement is performed while the heating element is rapidly cooled after heat generation, there is a problem that variations in temperature detection values increase due to minute variations in the measurement timing, resulting in reduced control accuracy. .

  The present invention has been made to solve these problems, and relates to a thermal head capable of detecting temperature with high accuracy without affecting printing speed and a thermal transfer printer including the thermal head.

  In order to solve the above problems, a thermal head according to the present invention includes a plurality of heating elements arranged in a predetermined direction, and a plurality of thermal elements arranged together with the heating elements between each heating element and at both ends of the arrangement. It is characterized by providing.

  According to the present invention, the plurality of heat generating elements are arranged in a predetermined direction, and the plurality of heat sensitive elements are arranged together with the heat generating elements between the heat generating elements and at both ends of the array. Is possible.

  Embodiments of the present invention will be described below with reference to the drawings.

<Embodiment 1>
FIG. 1 is a schematic configuration diagram of a printer according to an embodiment of the present invention. As shown in FIG. 1, the shaft 1 is provided on a frame (not shown), and the head arm 2 is rotatably supported by the shaft 1. The pressure spring 3 is attached between the upper frame and the lower frame of the head arm 2, and the thermal head 4 is attached to the lower frame of the head arm 2. The head arm vertical movement mechanism 5 is provided on a frame (not shown) above the head arm 2. The supply bobbin 6 and the take-up bobbin 7 are rotatably supported by a frame (not shown), respectively, and ink supplied from the supply bobbin 6 by a take-up bobbin drive mechanism 8 that engages with the take-up bobbin 7. The sheet 9 is wound on the winding bobbin 7. The platen roller 10 is rotatably supported by a frame (not shown) below the thermal head 4, and the image receiving paper 11 is wound around the platen roller 10 and guided. The conveying roller 12 engaged with the conveying roller driving mechanism 13 is pressure-bonded to the pinch roller 14, and the image receiving paper 11 is sandwiched between the conveying roller 12 and the pinch roller 14 and is separated from the platen roller 10 by the conveying roller driving mechanism 13. Be transported.

  FIG. 2 is a configuration diagram of the thermal head 4 according to the first embodiment of the present invention, and FIG. 2A shows a cross-sectional view of the thermal head. As shown in FIG. 2A, the heat radiating plate 15 is attached to the lower frame of the head arm 2, and the substrate 16 and the mounting substrate 17 are provided adjacent to each other on the heat radiating plate 15. A glaze layer 18 having rib-like glaze protrusions 19 is formed on the substrate 16, and a resistor pattern layer 20, an electrode pattern layer 21, and a protective film layer 22 are sequentially formed on the glaze layer 18. On the other hand, an integrated circuit 23 is installed on the mounting substrate 17.

  FIG. 2B is a view of the thermal head 4 as viewed from the platen 10 side. As shown in FIG. 2B, the integrated circuit 23 installed on the mounting substrate 17 is provided with a plurality of integrated circuit output terminals 24. The integrated circuit 23 is mounted on the mounting substrate 17 in the vicinity of the electrode pattern 21. A side common electrode pattern 25 is formed. The lower electrode pattern 26 is disposed so as to pass below the integrated circuit 23, and is provided on the side facing the relay terminal 27 across the integrated circuit 23 and the relay terminal 27 provided near the electrode pattern layer 21. The output terminal 28 is connected.

  The electrode pattern layer 21 is formed in a strip shape between the first electrode terminal 21 a formed near the mounting substrate 17 and exposed from the protective film layer 22, and between the first electrode terminal 21 a and the glaze protrusion 19. A plurality of first individual electrodes 21b and a U-shaped folded electrode arranged so as to face the individual electrodes 21b across the apex of the glaze protrusion 19 so that the two first individual electrodes 21b are arranged in parallel. 21c, a common electrode 21d disposed so as to surround the plurality of folded electrodes 21c, and the first individual electrodes 21b in units of pairs by the folded electrodes 21c, in parallel with the first individual electrodes 21b. A second individual electrode 21e arranged in a strip shape, and a second electrode terminal 21f formed near the mounting substrate 17 of the second individual electrode 21e and exposed from the protective film layer 22, Common electric 21d a vicinity mounting substrate 17 composed of a common electrode terminal 21g which is formed and exposed from the protective film layer 22.

  The heating element 29 is in the vicinity of the glaze protrusion 19 between the individual electrode 21b and the folded electrode 21c, and the resistor pattern layer 20 is formed up to just below the protective film layer 22, and in a predetermined direction (FIG. 2B). In the vertical direction). Here, the heating element 29 is a pair of heating elements connected by the folded electrode 21c. The thermal element 30 is in the vicinity of the glaze protrusion 19 between the second individual electrode 21e and the common electrode 21d, and the resistor pattern layer 20 is formed up to just below the protective film layer 22. The heat sensitive elements 30 are provided between the heat generating elements 29 and at both ends where the heat generating elements 29 are arranged, and are arranged together with the heat generating elements 29 in the predetermined direction. The wire bond wiring 31 is a wiring for connecting a terminal on the substrate 16 and a terminal on the mounting substrate 17, and specifically, the second electrode terminal 21f, the relay terminal 27, the common electrode terminal 21g, The mounting side common electrode pattern 25 is connected, and the integrated circuit output terminal 24 and the mounting side common electrode pattern 25 are alternately connected to the first electrode terminal 21a.

  Next, the operation of the printer in the first embodiment will be described.

  As shown in FIG. 1, when the head arm 2 applies a downward force to the thermal head 4 side by the head arm vertical movement mechanism 5, the upper frame of the head arm 2 rotates about the shaft 1, and the pressing spring 3. The thermal head 4 pushed downward by the pressure is pressed against the platen roller 10 via the ink sheet 9 and the image receiving paper 11. The contact pressure at the glaze protrusion 19 of the thermal head 4 is the largest, and the heat generated from the heating element 29 arranged near the apex of the glaze protrusion 19 is efficiently transmitted to the ink sheet 9 and the image receiving paper 11. .

  When the transport roller 12 is rotated by the transport roller driving mechanism 13, the image receiving paper 11 sandwiched between the transport roller 12 and the pinch roller 14 receives a frictional force and is transported from the platen roller 10 toward the transport roller 12. Is done. The ink sheet 9 is supplied from the supply bobbin 6, is brought into close contact with the image receiving paper 11, and is conveyed between the thermal head 4 and the platen roller 10. The ink sheet 9 that has passed through the platen roller 10 receives tension by the take-up bobbin 7 driven by the take-up bobbin drive mechanism 8 and is taken up after leaving the image receiving paper 11.

  As shown in FIG. 2, in the thermal head 4, in order from the integrated circuit output terminal 24, the wire bond wiring 31, the first electrode terminal 21 a, the first individual electrode 21 b, the heating element 29, the folded electrode 21 c, and the heating element 29. A circuit passing through the path of the first individual electrode 21b, the first electrode terminal 21a, and the mounting side common electrode pattern 25 is formed. That is, each heat generating element 29 in the present embodiment includes a pair of heat generating elements 29 connected by a folded electrode 21c folded in a U shape. Therefore, by inputting a predetermined control signal to the integrated circuit 24 and switching each integrated circuit output end 24, the pair of heat generating elements 29 can be selectively heated. Further, although the resistance value of the thermal element 30 varies depending on the temperature, the resistance value of the thermal element 30 can always be measured as the resistance value between the output terminal 28 and the mounting side common electrode pattern 25. The temperature can always be detected.

  When the heat generating element 29 is selectively heated in synchronization with the conveyance of the image receiving paper 11, the ink is selectively transferred from the ink sheet 9 onto the image receiving paper 11, and a desired image or Letters can be formed.

  FIG. 3 is an isotherm diagram showing a temperature distribution in the vicinity of the heating element 29 according to the first embodiment of the present invention. 3A is an isotherm diagram when three pairs of heating elements 29 are caused to generate heat, and FIG. 3B is an isotherm diagram when one pair of heating elements 29 is caused to generate heat. Although not shown, a heat sensitive element 30 is disposed between the heat generating elements 29. Here, the power supplied to the pair of heating elements 29 is 0.18 W, the applied pulse period is 1.3 milliseconds, the applied pulse duty is 50%, and the dimension of the heating element 29 in the short direction is 0. 0. 031 mm, the longitudinal dimension of the heating element 29 is 0.31 mm, and the spacing between the heating elements 29 is 0.011 mm.

  As shown in FIG. 3A, the temperature distribution when the three pairs of heat generating elements 29 are heated is a uniform distribution in the arrangement direction of the heat generating elements 29. Accordingly, the temperature between the heat generating elements 29 in which the heat sensitive elements 30 are disposed is equal to the temperature of the heat generating elements 29, and therefore the temperature detected by the heat sensitive elements 30 is equal to the heat generating elements 29. This is because both the heat generating element 29 and the heat sensitive element 30 are formed on the glaze protrusion 19, and the heat generated in the heat generating element 29 is along the glaze protrusion 19, that is, the heat generating element 29 and the heat sensitive element. This is because the element 30 tends to spread in the arrangement direction. Further, the dimension of the thermal element 30 in the short direction is equal to or smaller than the dimension of the heat generating element 29, and the material of the heat sensitive element 30 is the same as that of the heat generating element 29 and is a thin metal system of about 1 μm or less and has a small heat capacity. The temperature responsiveness is high and follows the temperature change of the heating element 29.

  On the other hand, as shown in FIG. 3B, when a pair of heat generating elements 29 is heated, the temperature detected by the heat sensitive element 30 is the temperature of the heat generating element 29 that has generated heat and the heat generated adjacent thereto. It becomes an intermediate value with the temperature of the non-heating element 29.

  Thus, it can be seen that the thermal element 30 can detect a value close to the average value of the temperatures of the heating elements 29 arranged on both sides of the thermal element 30.

  FIG. 4 is a diagram showing a temperature distribution when the three pairs of heat generating elements 29 according to the first embodiment of the present invention generate heat. As shown in FIG. 4, E0 to E6 schematically show the position and arrangement of the heating elements 29, and t0 to t6 show the temperatures of the heating elements 29 located at E0 to E6. S1 to S6 schematically show the position of the thermal element 30, and T1 to T6 show temperatures detected by the thermal element 30 located in S1 to S6. Here, it is assumed that the heating elements 29 located at E2, E3, and E4 are generating heat.

  Since the heat generating element 29 also has a temperature distribution inside, it is reasonable to evaluate the temperature using a representative temperature such as an average temperature or a maximum temperature. In this embodiment, the heat sensitive element 30 is used. A value close to the average temperature of the heating elements 29 calculated by the above is regarded as the temperature of the heating elements 29 and is applied to the temperature control.

  Next, a method for calculating the temperature of the heating element 29 from the thermal element 30 will be described.

  In the case of character printing, it is rare to form a line or a point with only one dot except for the end portion, and a character is usually formed using a line or a dot composed of a plurality of dots. When calculating the temperature of the heat generating element 29, first, a portion where the plurality of heat generating elements 29 generate heat is extracted. Then, the temperature of the heat sensitive element 30 positioned between the extracted heat generating elements 29 is detected, and the detected temperature is regarded as the temperature of the heat generating elements 29 adjacent to the heat sensitive element 30. Specifically, the thermal element 30 located at S3 shown in FIG. 4 is extracted to detect the temperature T3, and the detected temperature T3 is regarded as the temperatures t2 and t3 of the heating element 29 located at E2 and E3. Next, the temperature T2 detected by the thermal element 30 located at S2 is approximated to the average value (t1 + t2) / 2 of the temperature of the heating element 29 located at E1 and E2, and t2 is regarded as T3 as described above. Therefore, the temperature t1 of the heat generating element 29 located at E1 can be calculated. By repeating the above processing, the temperatures of all the heating elements 29 provided in the thermal head 4 can be calculated.

  Further, when three or more pairs of adjacent heating elements 29 are generating heat, by calculating the temperature of the heating elements 29 located in the center as an average value of the temperatures detected by the thermal elements 30 located on both sides, More accurate temperature detection is possible. Specifically, the temperature t3 of the heating element 29 located at E3 shown in FIG. 4 is calculated as an average value of the temperatures T3 and T4 detected by the thermal element 30 located at S3 and S4. Then, t2 and t4 can be calculated from t3, T3, and T4 that have become known. By repeating the above processing, the temperatures of all the heating elements 29 provided in the thermal head 4 can be calculated.

  In the case of image printing, the portion corresponding to the end portion is smaller than the character, and adjacent pixels have a size and density close to each other and gradually change to form an image. The target temperatures to be controlled are close to each other. Therefore, as described above, it is possible to accurately detect the temperature by calculating the temperature of the heating element 29 as the average value of the temperatures detected by the thermal elements 30 located on both sides.

  FIG. 5 is a graph showing a ratio of the dimension of the heating element 29 and the dimension of the transfer ink with respect to the application time of the thermal head 4 according to the first embodiment of the present invention. Here, the dimension in the short direction of the heating element 29 is 0.013 mm, the dimension in the longitudinal direction of the heating element 29 is 0.06 mm, and the power applied to the heating element 29 is 0.07 W, and the application time is changed. The relationship of the size of the ink transferred to the image receiving paper 11 when measured is measured. For simplification of description, the size of the ink transferred to the image receiving paper 11 is set to 1 in the short direction of the heating element 29. As shown in FIG. 4, the temperature of the heating element 29 at the time of transfer increases as the power application time to the heating element 29 increases. As shown in FIG. 5, when the power application time is increased with respect to the heat generating element 29, the size of the transferred ink becomes large, which is more than three times the dimension of the heat generating element 29 in the arrangement direction.

  As described above, even if the space between the heat generating elements 29 is widened and the thermal element 30 and the insulating portion formed between the adjacent heat generating elements 29 and the thermal element 30 are provided therebetween, the ink can be transferred without being spaced at the time of printing. You can see that you can. In addition, since the size of the transferred ink can be three times or more the arrangement direction of the heat generating elements 29, the dimension in the arrangement direction of the heat sensitive elements 30 is formed between the heat generating elements 29 and the heat sensitive elements 30. In addition, the total dimension with the distance between the insulating portions may be equal to or smaller than the dimension in the arrangement direction of the heating elements 29. Therefore, in the present embodiment, the width in the arrangement direction of the heat generating elements 29 can be realized as long as it is 1/3 or less of the arrangement pitch width (printer resolution) of the heat generating elements 29. No manufacturing equipment is required.

  In the first embodiment, the case where the heating element 29 and the thermal element 30 are formed from the same resistor pattern layer 20 has been described. However, the thermal element 30 is more resistant than the material of the resistor pattern layer 20 such as a thermistor material. You may form with a material with a large temperature coefficient.

  From the above, since the plurality of heat sensitive elements 30 are arranged together with the heat generating elements 29 between the heat generating elements 29 and at both ends of the arrangement of the heat generating elements 29, heat transfer between the heat generating elements 29 and the ink sheet 9 is performed. The temperature of the heating element 29 can be detected without hindering. In addition, since the heating element 29 and the thermal element 30 can be formed at the same time in a single process, the manufacturing process can be reduced. Further, since the power feeding circuit to the heating element 29 and the detection circuit of the thermal element 30 are configured in parallel, the temperature detection operation does not become a time constraint on the control of the heat generation, and the heating element 29 By constantly controlling the heat generation, efficient printing is possible, which is advantageous for high-speed printing, and it is possible to suppress variations in detection values due to a decrease in heat generation control accuracy and variations in temperature detection timing.

<Embodiment 2>
FIG. 6 is a configuration diagram of the thermal head 4 according to the second embodiment of the present invention. In the second embodiment, as shown in FIG. 6, the longitudinal direction of the heat generating elements 29 is arranged so as to be inclined at a predetermined angle from the direction orthogonal to the arrangement direction of the heat generating elements 29 (the left-right direction in FIG. 7). It is characterized by that. Since other configurations are the same as those of the first embodiment, description thereof is omitted here.

  As shown in FIG. 6, the ink sheet 9 and the image receiving paper 11 are conveyed in the direction of the arrow A, and the ink is transferred to the image receiving paper 11 by the heat generated by the heating element 29. In the second embodiment, the first individual electrode 21b and the folded electrode 21c are formed so that the heating element 29 has a rectangular shape.

  From the above, in the second embodiment, since the heat generating elements 29 are disposed at a predetermined angle, the passage width of the portion where no heat is generated between the heat generating elements 29 when the image receiving paper 11 is conveyed is narrowed. Therefore, it is possible to transfer the ink without a gap with a smaller amount of heat generation. Further, by adopting the structure as in the second embodiment, the adaptability to the sublimation transfer method and the thermal recording method in which the spread of the ink is smaller than the melt transfer method is improved.

<Embodiment 3>
FIG. 7 is a configuration diagram of the thermal head 4 according to the third embodiment of the present invention. In the third embodiment, as shown in FIG. 7, the longitudinal direction of the heating elements 29 is arranged at a predetermined angle from the direction orthogonal to the arrangement direction of the heating elements 29, and the inclination of the heating elements 29 is The deviation width δ due to is characterized by being larger than the width W of the heating elements 29 in the arrangement direction. Since other configurations are the same as those of the second embodiment, the description thereof is omitted here.

  As shown in FIG. 7, the ink sheet 9 and the image receiving paper 11 are conveyed in the direction of arrow A, and the ink is transferred to the image receiving paper 11 by the heat generated by the heating element 29. In the third embodiment, the first individual electrode 21b and the folded electrode 21c are formed so that the heating element 29 forms a parallelogram. Since the heat generating element 29 is disposed at a predetermined angle, the passage width of the portion that does not generate heat between the heat generating elements 29 when the image receiving paper 11 is transported can be reduced, and the ink is spaced with a smaller heat generation amount. It is possible to transfer without leaving a gap. However, since the current flowing inside the heat generating element 29 is concentrated on a path with a small resistance, the amount of heat generated may be reduced depending on the inclination condition of the heat generating element 29.

  For example, when the deviation width δ due to the inclination of the heating element 29 is smaller than the width W in the arrangement direction of the heating elements 29 and there is a portion where the first individual electrode 21b and the folded electrode 21c face each other, a path connecting the facing portions The resistance is minimized and the current is concentrated. Thus, if the current concentrates on a certain path, the passage width of the portion where the heat generating element 29 does not generate heat when the image receiving paper 11 is transported becomes wide. Therefore, in order to widen the heat generation part by the heat generating element 29, it is necessary to make the deviation width δ due to the inclination of the heat generating element 29 larger than the width W in the arrangement direction of the heat generating elements 29.

  From the above, in the third embodiment, the heat generating element 29 is inclined at a predetermined angle, and the deviation width δ due to the inclination of the heat generating element 29 is made larger than the width W in the arrangement direction of the heat generating elements 29 to generate the heat generating portion. Is widened in the arrangement direction of the heat generating elements 29, so that the passage width of the portion that does not generate heat between the heat generating elements 29 when the image receiving paper 11 is conveyed can be narrowed, and the ink is spaced with a smaller amount of heat generation. It is possible to transfer without being transferred. Further, by adopting the structure as in the third embodiment, adaptability to the sublimation transfer method and the thermal recording method in which the spread of ink is smaller than that of the melt transfer method is improved.

1 is a schematic configuration diagram of a printer according to an embodiment of the present invention. It is a block diagram of the thermal head by Embodiment 1 of this invention. It is an isotherm figure which shows the temperature distribution of the vicinity of the heat generating element by Embodiment 1 of this invention. It is a figure which shows temperature distribution when the three pairs of heat generating elements according to Embodiment 1 of the present invention generate heat. It is a graph which shows ratio of the heat generating element dimension with respect to the application time of the thermal head by Embodiment 1 of this invention, and a transfer ink dimension. It is a block diagram of the thermal head by Embodiment 2 of this invention. It is a block diagram of the thermal head by Embodiment 3 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Shaft, 2 Head arm, 3 Pressing spring, 4 Thermal head, 5 Head arm up-and-down moving mechanism, 6 Supply bobbin, 7 Winding bobbin, 8 Winding bobbin drive mechanism, 9 Ink sheet, 10 Platen roller, 11 Image receiving paper , 12 transport roller, 13 transport roller drive mechanism, 14 pinch roller, 15 heat sink, 16 substrate, 17 mounting substrate, 18 glaze layer, 19 glaze protrusion, 20 resistor pattern layer, 21 electrode pattern layer, 21a first Electrode terminal, 21b first individual electrode, 21c folded electrode, 21d common electrode, 21e second individual electrode, 21f second electrode terminal, 21g common electrode terminal, 22 protective film layer, 23 integrated circuit, 24 integrated circuit output Terminal, 25 Mounting side common electrode pattern, 26 Lower layer electrode pattern, 27 Relay terminal 28 an output terminal, 29 heating elements 30 heat sensitive element, 31 wire bonding wirings.

Claims (6)

A plurality of heating elements arranged in a predetermined direction;
A plurality of thermal elements arranged together with the heating elements between the heating elements and at both ends of the arrangement;
A thermal head.   2. The thermal head according to claim 1, wherein a longitudinal direction of the heat generating element is inclined at a predetermined angle from a direction orthogonal to the predetermined direction.   The thermal head according to claim 2, wherein a deviation width due to the inclination of the heating element is larger than a width of the heating element in the predetermined direction.   4. The thermal head according to claim 1, wherein a width of the heating element in the predetermined direction is 1/3 or less of an arrangement pitch width of the heating elements. 5.   4. The thermal head according to claim 1, wherein each of the heat generating elements includes a pair of heat generating elements connected by electrodes folded back in a U-shape.   A thermal transfer printer comprising the thermal head according to any one of claims 1 to 5.

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