Thermal printheads and thermal printers

Abstract

We provide a thermal print head capable of printing at two different resolutions. [Solution] The thermal print head (1) comprises a common electrode (20), a plurality of individual electrodes (31, 32), and a plurality of heating elements (41, 42) respectively positioned between the common electrode (20) and the plurality of individual electrodes (31, 32). The plurality of individual electrodes include a plurality of first electrodes (31) whose Y-axis dimension of the portion adjacent to their respective heating element is width W1, and a plurality of second electrodes (32) whose Y-axis dimension of the portion adjacent to their respective heating element is width W2, which is shorter than width W1. The plurality of individual electrodes are arranged in a pattern in which a basic pattern C, in which one first electrode (31), two second electrodes (32), and one first electrode (31) are arranged in this order along the X-axis, is repeated multiple times along the X-axis.

Description

Technical Field

[0001] The present disclosure relates to a thermal print head and a thermal printer equipped with the thermal print head.

Background Art

[0002] Conventionally, Japanese Unexamined Patent Application Publication No. 2023-30169 (Patent Document 1) discloses a thermal print head that includes a common electrode, a plurality of individual electrodes, and a plurality of heat generating portions respectively disposed between the common electrode and the plurality of individual electrodes. This thermal print head can perform printing on a printing medium by causing the heat generating portions to generate heat by energizing the plurality of heat generating portions.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0004] [Summary] The mainstream resolutions of print data from thermal print heads are 200 dpi (dot per inch) or 300 dpi. When the resolution required for print data varies depending on the use of the print data, set manufacturers and users of thermal printers equipped with thermal print heads need to prepare respective thermal heads matching the resolution of the print data according to the use, and the selection is complicated. Under such circumstances, it is desired that two types of resolutions, 200 dpi and 300 dpi, can be realized simultaneously with a single thermal head.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a thermal print head and a thermal printer capable of printing at two types of resolutions (for example, 200 dpi and 300 dpi).

[0006] The thermal print head according to this disclosure comprises a substrate, a common electrode disposed on the surface of the substrate so as to extend in a first direction, a plurality of individual electrodes arranged on the surface of the substrate in a first direction and positioned at a predetermined distance from the common electrode in a second direction perpendicular to the first direction, and a plurality of heating elements disposed between the common electrode and the plurality of individual electrodes. The plurality of individual electrodes include a plurality of first electrodes, each having a first value for the dimension of the portion adjacent to its corresponding heating element in the first direction, and a plurality of second electrodes, each having a second value for the dimension of the portion adjacent to its corresponding heating element in the first direction, which is shorter than the first value. The plurality of individual electrodes are arranged in a pattern in which a basic pattern of one first electrode, two second electrodes, and one first electrode arranged in this order in the first direction is repeated a plurality of times along the first direction.

[0007] The thermal printer of this disclosure comprises the thermal print head described above and a control device that performs printing on a printing medium by supplying power to a plurality of heating elements. [Brief explanation of the drawing]

[0008] [Figure 1] This diagram schematically shows the configuration of a thermal printer equipped with a thermal printhead. [Figure 2] This diagram shows the printing process using a thermal printhead. [Figure 3] This is a schematic plan view of a thermal print head. [Figure 4] This is a magnified plan view (part 1) of a key part of the thermal print head. [Figure 5] This diagram shows the control image in the first mode (300 dpi). [Figure 6] This figure shows the control image in the second mode (200 dpi). [Figure 7] This diagram shows the print image in the first mode (300 dpi) and the print image in the second mode (200 dpi). [Figure 8]This flowchart shows an example of the process procedure for the control device to set the control mode of the thermal printer. [Figure 9] This figure shows an image illustrating the control of the number of power-on cycles in the second mode (200 dpi). [Figure 10] This is a magnified plan view (part 2) of a key part of the thermal print head.

[0009] [Detailed explanation] The details of the embodiments of this disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts will be given the same reference numerals, and their descriptions will not be repeated. At least some of the configurations of the embodiments described below may be combined in any way.

[0010] <Overall Structure> Figure 1 is a schematic diagram showing the configuration of a thermal printer 100 equipped with a thermal print head 1 according to this embodiment. The thermal printer 100 includes a thermal print head 1, a control device 101, a platen roller 102, a winding device 103, and a power supply 104. The power supply 104 supplies current to the thermal print head 1 and the control device 101.

[0011] The thermal printhead 1 prints on the printing medium by generating heat. Generally, thermal printheads are classified into types such as thick film type, thin film type, and special type in which the heating substrate has a three-dimensional shape due to special processing, depending on the manufacturing method, the substrate that forms the heating element, other constituent materials, and product structure. However, the thermal printhead 1 according to this embodiment can be applied to any of these types.

[0012] The thermal print head 1 includes a driver circuit 5. The driver circuit 5 includes multiple switching elements for controlling the supply of power to multiple heat-generating parts. The driver circuit 5 performs printing on the printing medium by switching the state of the multiple switching elements to an on (conducting) or off (non-conducting) state based on a signal from the control device 101 to control the supply of power to the multiple heat-generating parts.

[0013] The platen roller 102 is controlled by the control device 101 and is a component that is pressed against the thermal print head 1 via the printing medium when the thermal print head 1 transports the printing medium from the paper feed side to the paper discharge side and prints onto the printing medium. Thermal printers have two types of printing methods: thermal printing, which uses the heat of the printing medium to produce color, and thermal transfer printing, which uses an ink ribbon in between. In the case of thermal transfer printing, the winding device 103 is controlled by the control device 101 and is a mechanism for winding up the ink ribbon after the transfer.

[0014] The control device 101 includes an arithmetic unit 111 and a storage unit 112. The arithmetic unit 111 is an arithmetic entity (computer) that performs predetermined processing. The arithmetic unit 111 is composed of a processor such as an MCU (Micro Controller Unit), CPU (Central Processing Unit), MPU (Micro-Processing Unit), TPU (Tensor Processing Unit), or GPU (Graphics Processing Unit).

[0015] The storage unit 112 is implemented by non-volatile memory such as RAM (Random Access Memory), ROM (Read Only Memory), and flash memory, and storage devices such as magnetic disks. The storage unit 112 stores programs executed by the arithmetic unit 111, or data used by the arithmetic unit 111. The storage unit 112 may also be interpreted as a processing circuitry that has the function of holding data or signals.

[0016] The calculation unit 111 calculates the power supply signal to be sent to the driver circuit 5 based on the information stored in the memory unit 112. The power supply signal is a command signal for controlling the power supply to multiple heat-generating parts (the state of the switching elements of the driver circuit 5), which will be described later. The thermal print head 1 prints on the printing medium based on the power supply signal transmitted from the control device 101 to the driver circuit 5.

[0017] Figure 2 is a diagram showing a state of printing using the thermal print head 1. The thermal print head 1 is disposed to face the cylindrical platen roller 102. The print medium is disposed between the heat generating portion 40 of the thermal print head 1 and the platen roller 102. As shown in Figure 2(A), the print medium according to the present embodiment is composed of an ink ribbon 201 and a paper 202, and is conveyed from the paper feed side to the paper discharge side by the rotation of the platen roller 102. The ink ribbon 201 melts the ink by thermal energy generated by the heat generating portion 40 of the thermal print head 1 and transfers the ink to the paper. The winding device 103 is a device for winding up the ink ribbon 201 after transfer. The print medium may be a thermal paper coated with a chemical that changes color by causing a chemical reaction upon sensing heat. When the print medium is a thermal paper as shown in Figure 2(B), the ink ribbon 201 and the winding device 103 are not required.

[0018] Figure 3 is a plan view schematically showing the thermal print head 1. The thermal print head 1 has a flat plate shape that is rectangular in a plan view. Hereinafter, when the thermal print head 1 is viewed in a plan view, the longitudinal direction of the thermal print head 1 is also referred to as "X-axis direction", the lateral direction of the thermal print head 1 is also referred to as "Y-axis direction", and the thickness direction of the thermal print head 1 is also referred to as "Z-axis direction". The X-axis direction is also referred to as "main scanning direction", and the Y-axis direction is also referred to as "sub scanning direction".

[0019] The thermal print head 1 includes, in addition to the driver circuit 5, a substrate 11, a circuit board 12, a connector 13, a wiring 14, a pad portion 15, a wire portion 16, a common electrode 20, an individual electrode portion 30, and a heat generating portion 40. The connector 13 includes a control connector 13A and a power supply connector 13B. The thermal print head 1 is connected to the control device 101 via the connector 13A, and is connected to the power supply 104 via the connector 13B.

[0020] The substrate 11 and the circuit substrate 12 are flat plate-shaped members extending long in the X-axis direction. On the substrate 11, a common electrode 20, individual electrode portions 30, heat generating portions 40, wirings 14, and pad portions 15 are provided. A wire portion 16 is provided extending across from the substrate 11 to the circuit substrate 12, and a driver circuit 5 is provided on the circuit substrate 12. Although not shown in FIG. 3, the wire portion 16 and the driver circuit 5 are covered and protected by a resin.

[0021] The common electrode 20 and the individual electrode portions 30 are formed of a conductive material, and constitute a conduction path for supplying current to the heat generating portions 40. The heat generating portions 40 are formed of a resistor, and generate heat when current flows therethrough. The common electrode 20 and the individual electrode portions 30 are made of a metal material with lower resistance than the heat generating portions 40. For example, the common electrode 20 and the individual electrode portions 30 may include a layer made of copper (Cu), aluminum (Al), or gold (Au), and a layer made of titanium (Ti). The heat generating portions 40 may be made of tantalum nitride (TaN).

[0022] The common electrode 20 has a base portion 23 disposed on the surface of the substrate 11 so as to extend in the X-axis direction. The individual electrode portions 30 are disposed at positions spaced a predetermined distance from the base portion 23 of the common electrode 20 in the Y-axis negative direction. The heat generating portions 40 are disposed between the common electrode 20 and the individual electrode portions 30.

[0023] Although not shown in FIG. 3, the individual electrode portions 30 are constituted by a plurality of individual electrodes arranged in the X-axis direction at predetermined intervals. The wirings 14 are constituted by a plurality of conductive members that respectively connect the plurality of individual electrodes and the plurality of connection pads constituting the pad portions 15. The heat generating portions 40 are constituted by a plurality of heat generating portions respectively disposed between the common electrode 20 and the plurality of individual electrodes constituting the individual electrode portions 30. The details of the shapes and arrangements of the common electrode 20, the individual electrode portions 30, and the heat generating portions 40 will be described in detail later with reference to FIG. 4.

[0024] The wire section 16 is composed of multiple connecting wires that connect the multiple connecting pads constituting the pad section 15 to the multiple switching elements included in the driver circuit 5. As a result, the individual electrode section 30 is connected to the multiple switching elements included in the driver circuit 5 via the wire section 16.

[0025] Figure 4 is an enlarged plan view of a portion of the main part of the thermal print head 1 (common electrode 20, individual electrode section 30, and heating section 40). As shown in Figure 4, the individual electrode section 30 is composed of a plurality of individual electrodes arranged in the X-axis direction at predetermined intervals. Each of the plurality of individual electrodes extends in the Y-axis direction. The plurality of individual electrodes are connected to a plurality of switching elements included in the driver circuit 5 via wiring 14.

[0026] The individual electrode section 30 includes multiple individual electrodes, namely multiple first electrodes 31 and multiple second electrodes 32. The width (dimension in the X-axis direction) of each first electrode 31 and the width of each second electrode 32 are different from each other. The width of each first electrode 31 is set to a width W1 that corresponds to the width of one dot when the printing resolution is 300 dpi. The width of each second electrode 32 is set to a width W2 that is narrower than the width W1. When the width of the gap between adjacent individual electrodes is called "gap G", the width W2 of each second electrode 32 is set to a value such that the relationship "W2 + G + W2 = W1" holds true (i.e., the sum of a value greater than the width W2 (more specifically, twice the width W2) and the gap G is approximately equal to the width W1 of each first electrode 31). Note that as long as the above relationship holds true, the shape of each first electrode 31 and each second electrode 32 is not limited to a rectangular shape; they may also be irregularly shaped.

[0027] The multiple individual electrodes constituting the individual electrode section 30 are arranged in a pattern in which a basic pattern C, in which one first electrode 31, two second electrodes 32, and one first electrode 31 are arranged in this order along the X-axis, is repeated multiple times along the X-axis. Each basic pattern C includes a first pattern A in which one first electrode 31 and one second electrode 32 are arranged in this order along the positive X-axis, and a second pattern B in which one second electrode 32 and one first electrode 31 are arranged in this order along the positive X-axis. The first pattern A and the second pattern B are symmetrical with respect to a line extending in the Y-axis direction through the center of the basic pattern C in the X-axis direction.

[0028] The heating element 40 is composed of multiple heating elements, each positioned between the common electrode 20 and the multiple individual electrodes. Specifically, the heating element 40 includes multiple first heating elements 41 and multiple second heating elements 42. The multiple first heating elements 41 are each positioned between the common electrode 20 and the multiple first electrodes 31. The width (dimension in the X-axis direction) of each first heating element 41 is the same as the width W1 of each first electrode 31. The multiple second heating elements 42 are each positioned between the common electrode 20 and the multiple second electrodes 32. The width (dimension in the X-axis direction) of each second heating element 42 is the same as the width W2 of each second electrode 32.

[0029] The common electrode 20 shown in Figure 4 is composed of a base portion 23 extending in the X-axis direction, a plurality of first protrusions 21 each extending in the Y-axis direction from the base portion 23 toward the first heating portion 41, and a plurality of second protrusions 22 each extending in the Y-axis direction from the base portion 23 toward the second heating portion 42. The width (dimension in the X-axis direction) of each first protrusion 21 is width W1, and the width (dimension in the X-axis direction) of each second protrusion 22 is width W2.

[0030] The thermal print head 1 according to this embodiment, having the configuration described above, is capable of printing at two resolutions, 200 dpi and 300 dpi. Below, we will describe the control of printing a print pattern that alternates between black and white in the X-axis direction (main scanning direction) at two resolutions, 200 dpi and 300 dpi, using the thermal print head 1.

[0031] <Printing at two different resolutions using thermal print head 1> The control device 101 according to this embodiment is configured to switch the control mode of the thermal printer 100 equipped with a thermal print head 1 between a first mode in which the print resolution is 300 dpi (first resolution) and a second mode in which the print resolution is lower than 300 dpi, at 200 dpi (second resolution).

[0032] Figure 5 shows a control image in the first mode with a printing resolution of 300 dpi. Figure 6 shows a control image in the second mode with a printing resolution of 200 dpi. In Figures 5 and 6, for the sake of simplicity, eight individual electrodes included in two basic patterns C are shown as individual electrode sections 30, and eight switching elements Q1 to Q8 of the driver circuit 5 connected to each of the eight individual electrodes are also shown.

[0033] In the first mode (300 dpi), the control device 101 turns on (conducts) one switching element connected to one first electrode 31, or two switching elements connected to two adjacent second electrodes 32, respectively, to print one dot at 300 dpi. For example, as shown in Figure 5, the control device 101 turns on switching element Q1, thereby heating one first heating element 41 connected to switching element Q1 and printing a character with width W1. The control device 101 also turns on switching element Q4, thereby heating the first heating element 41 connected to switching element Q4 and printing a character with width W1. Furthermore, the control device 101 turns on switching elements Q6 and Q7, thereby heating two adjacent second heating elements 42 connected to switching elements Q6 and Q7 and printing a character with width W1. Furthermore, the distance between the centers of the area corresponding to one dot size enclosed by the dashed line in Figure 5 (the length of each thick arrow) in the X-axis direction corresponds to the resolution in the X-axis direction in the first mode (300 dpi). At 300 dpi, the distance between the centers shown in Figure 5 is approximately 0.0847 mm.

[0034] In the second mode (200 dpi), the control device 101 performs printing of one dot at 200 dpi by making two switching elements connected to adjacent first electrodes 31 and 32 conduct electricity. For example, as shown in Figure 6, the control device 101 turns on switching elements Q1 and Q2, thereby heating adjacent first heating elements 41 and 42 connected to switching elements Q1 and Q2, and performing printing of width W3. Width W3 is the sum of width W1, gap G, and width W2. The control device 101 also turns on switching elements Q5 and Q6, thereby heating adjacent first heating elements 41 and 42 connected to switching elements Q5 and Q6, and performing printing of width W3. Furthermore, the distance between the centers of the area corresponding to one dot size enclosed by the dashed line in Figure 6 (the length of each thick arrow) in the X-axis direction corresponds to the X-axis resolution in the second mode (200 dpi). At 200 dpi, the distance between the centers shown in Figure 6 is approximately 0.125 mm.

[0035] Figure 7 shows the print image in the first mode (300 dpi) and the print image in the second mode (200 dpi). In Figure 7, the shaded area represents the print of one dot. As shown in Figure 7, the thermal printer 100 according to this embodiment can perform both 300 dpi and 200 dpi printing by having one thermal print head 1. Figure 7 also shows an example in which the print speed (the speed at which the printing medium is transported in the sub-scanning direction) is set to a print speed V1 based on 300 dpi in both the first and second modes.

[0036] Figure 8 is a flowchart showing an example of the process procedure by which the control device 101 sets the control mode of the thermal printer 100. This flowchart is executed repeatedly at predetermined intervals while the thermal printer 100 is operating. Note that Figure 8 shows an example based on a resolution of 300 dpi.

[0037] First, the control device 101 determines whether or not there is a request to switch to a resolution of 200 dpi (step S10). For example, the control device 101 determines that there is a request to switch to a resolution of 200 dpi if it detects that the user of the thermal printer 100 has performed an operation to set the print resolution to 200 dpi.

[0038] If there is no request to switch to a resolution of 200 dpi (NO in step S10), the control device 101 sets the control mode of the thermal printer 100 to the first mode (300 dpi) described above (step S20).

[0039] If there is a request to switch to a resolution of 200 dpi (YES in step S10), the control device 101 sets the control mode of the thermal printer 100 to the second mode (200 dpi) described above (step S30).

[0040] As described above, the thermal print head 1 according to this embodiment includes a plurality of individual electrodes, each having a width W1 equivalent to the width of one 300 dpi dot, and a plurality of second electrodes 32 each having a width W2 shorter than the width W1. These plurality of individual electrodes are arranged in a pattern in which a basic pattern C, in which one first electrode 31, two second electrodes 32, and one first electrode 31 are arranged in this order in the X-axis direction, is repeated multiple times along the X-axis direction.

[0041] With this configuration, printing with a width of one dot at 300 dpi can be performed by energizing one first electrode 31 or two adjacent second electrodes 32. Alternatively, printing with a width of one dot at 200 dpi can be performed by energizing one adjacent first electrode 31 and one adjacent second electrode 32.

[0042] Furthermore, in the second mode (200 dpi), if printing is simply performed at the same printing speed V1 as in the first mode (300 dpi), as shown in Figure 7 above, the printed dimensions in the printing direction (sub-scanning direction) become shorter than the dimensions of one dot at 200 dpi, and gaps may occur between dots.

[0043] Therefore, in the first mode (300 dpi), the control device 101 sets the printing speed to a printing speed V1 based on 300 dpi, and the number of times the heat-generating element is energized per dot is set to 1. On the other hand, in the second mode (200 dpi), the control device 101 maintains the printing speed at the same printing speed V1 as in the first mode, while setting the number of times the heat-generating element is energized per dot to 2.

[0044] Figure 9 shows an image illustrating the control of the number of power-on cycles in the second mode (200 dpi). In the second mode, the number of times power is applied to the heating element per dot is set to two. Specifically, after the first power-on (printing) cycle, the second power-on (printing) cycle is performed when the printing medium has been transported by 0.5 dots. As a result, the printing dimension in the sub-scanning direction per dot in the second mode becomes longer compared to when the number of power-on cycles is set to one, and is adjusted to the dimension of one dot at 200 dpi. Consequently, gaps between dots are suppressed, allowing for proper printing at 200 dpi.

[0045] Furthermore, after the first power-on, if the printing medium is transported by 0.5 dots before the second power-on, some overlapping areas will occur. However, this is not expected to be a problem if the color reproduction in these areas is good. In addition, the transport in the sub-scanning direction may be 0.75 dots twice.

[0046] As a result, a single thermal print head 1 can print at two different resolutions, 200 dpi and 300 dpi. Consequently, users of the thermal printer 100 can print at two different resolutions, 200 dpi and 300 dpi, without having to replace the thermal print head 1.

[0047] Furthermore, the thermal print head 1 according to this embodiment can reduce manufacturing costs and manufacturing load compared to a case where only fine second electrodes 32 are provided as multiple individual electrodes. That is, a thermal print head that only has fine second electrodes 32 as multiple individual electrodes can print fine details equivalent to 600 dpi by energizing one second electrode 32, and can support two different resolutions, 200 dpi and 300 dpi, by energizing two adjacent second electrodes 32 or three pairs of second electrodes 32. However, in order to create a fine pattern equivalent to 600 dpi, a more expensive control circuit is required, and the number of connecting wires also increases, resulting in a considerably higher manufacturing cost. In addition, the number of connecting wires to be processed also increases, and the difficulty of processing also increases, thus increasing the manufacturing load. In contrast, the thermal print head 1 according to this embodiment mixes wider first electrodes 31 in addition to the second electrodes 32. Therefore, the thermal print head 1 according to this embodiment can reduce the number of fine second electrodes 32 compared to the case where only the second electrode 32 is provided, thereby reducing manufacturing costs and manufacturing load.

[0048] [Example 1] Figure 10 is an enlarged plan view of a part of the main section of the thermal print head 1A according to this modification 1. The thermal print head 1A has multiple slits 50 added to the thermal print head 1 described above. The other configurations of the thermal print head 1A are the same as those of the thermal print head 1 described above.

[0049] Multiple slits 50 are formed in each of the multiple first heating elements 41. Each slit 50 is formed in the center of each first heating element 41 in the X-axis direction and extends in the Y-axis direction. This reduces the difference between the temperature distribution of the first heating element 41 in contact with the first electrode 31 and the temperature distribution of the second heating element 42 in contact with the second electrode 32.

[0050] In other words, the temperature distribution of both the first heating element 41 and the second heating element 42 is circular or elliptical in shape, with the center being the hottest part where heat is difficult to escape and the temperature decreasing as you approach the periphery. However, in the absence of the slit 50, the width W1 of the first heating element 41 is about twice as large as the width W2 of the second heating element 42, so the temperature distribution of the first heating element 41 may be more non-uniform overall than the temperature distribution of the second heating element 42.

[0051] In the thermal print head 1A of this modified example 1, a slit 50 is made in the center of the first heating element 41 in the X-axis direction, thereby dividing the first heating element 41 into two parts. This makes it easier to make the temperature distribution of the first heating element 41 uniform and reduces the difference between the temperature distribution of the first heating element 41 and the temperature distribution of the second heating element 42. As a result, the difference between the printed shape produced by the first heating element 41 and the printed shape produced by the second heating element 42 can be reduced.

[0052] Although Figure 10 shows an example in which slits 50 are formed in all of the multiple first heat-generating parts 41, slits 50 may be formed in only some of the multiple first heat-generating parts 41. For example, in the first heat-generating part 41 located at the end in the X-axis direction of the multiple first heat-generating parts 41, heat tends to escape more easily than in the other first heat-generating parts 41, so slits 50 may not be provided.

[0053] [Differentiation 2] In the above-described embodiment, an example is shown in which the width of the first electrode 31 (dimension in the X-axis direction) is constant at width W1 regardless of the position in the Y-axis direction, and the width of the second electrode 32 is constant at width W2 regardless of the position in the Y-axis direction.

[0054] However, if the width of the portion of the first electrode 31 adjacent to the first heating element 41 is width W1, and the width of the portion of the second electrode 32 adjacent to the second heating element 42 is width W2, then the width of the first electrode 31 is not necessarily limited to being constant at width W1 regardless of its position in the Y-axis direction, nor is it necessarily limited to the width of the second electrode 32 being constant at width W2 regardless of its position in the Y-axis direction. For example, the width of the first electrode 31 may be configured to become narrower as it approaches the end in the negative Y-axis direction (as it approaches the driver circuit 5), or the width of the second electrode 32 may be configured to become narrower as it approaches the end in the negative Y-axis direction (as it approaches the driver circuit 5).

[0055] The various aspects of this disclosure are summarized below as an appendix.

[0056] [Note] [Note 1] circuit board and A common electrode is arranged on the surface of the substrate so as to extend in a first direction, A plurality of individual electrodes are arranged on the surface of the substrate in the first direction and are positioned at a predetermined distance from the common electrode in a second direction perpendicular to the first direction, The system comprises a plurality of heating elements, each positioned between the common electrode and the plurality of individual electrodes. The aforementioned plurality of individual electrodes are A plurality of first electrodes, each having a first value for the dimension in the first direction of the portion adjacent to the corresponding heating element, It includes a plurality of second electrodes, each of which has a second value, where the dimension in the first direction of the portion adjacent to the corresponding heating element is shorter than the first value, The plurality of individual electrodes are arranged in a thermal print head in a pattern in which a basic pattern in which one first electrode, two second electrodes, and one first electrode are arranged in this order in the first direction is repeated multiple times along the first direction.

[0057] [Note 2] The thermal print head as described in Appendix 1, wherein the first value is approximately equal to the sum of a value greater than the second value and the dimension of the gap between adjacent individual electrodes in the first direction.

[0058] [Note 3] The aforementioned multiple heating elements are A plurality of first heating elements are disposed between the common electrode and the plurality of first electrodes, A thermal print head according to Appendix 1 or 2, comprising a plurality of second heating elements, each disposed between the common electrode and the plurality of second electrodes.

[0059] [Note 4] The thermal print head according to Appendix 3, wherein a slit portion extending in the second direction is formed in the center of at least one of the plurality of first heating elements in the first direction.

[0060] [Note 5] A thermal print head according to any one of the appendices 1 to 4, further comprising a driver circuit having a plurality of switching elements connected to each of the plurality of individual electrodes.

[0061] [Note 6] The thermal print head described in Appendix 5, A thermal printer comprising a control device that performs printing on a printing medium by controlling the state of the plurality of switching elements of the driver circuit and supplying power to the plurality of heating elements.

[0062] [Note 7] The control device is capable of switching between a first mode in which the printing resolution is a first resolution and a second mode in which the printing resolution is a second resolution lower than the first resolution. The control device is In the first mode, one dot is printed by making one switching element connected to one of the first electrodes, or two switching elements connected to two adjacent second electrodes, conduction. The thermal printer described in Appendix 6, which in the second mode performs printing of one dot by making two switching elements, each connected to one adjacent first electrode and one adjacent second electrode, conductious.

[0063] [Note 8] The control device is In the first mode, the printing speed is set to a first speed, and the number of times power is applied per dot is set to one. The thermal printer described in Appendix 7, wherein in the second mode, the printing speed is maintained at the first speed, and the number of times power is applied per dot is two.

[0064] While embodiments of this disclosure have been described above, it is possible to modify these embodiments in various ways. Furthermore, the scope of this disclosure is not limited to the embodiments described above. The scope of this disclosure is indicated by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims. [Explanation of Symbols]

[0065] 1,1A Thermal print head, 5 Driver circuit, 11 Circuit board, 12 Circuit board, 13 Connector, 14 Wiring, 15 Pad section, 16 Wire section, 20 Common electrode, 21 First protrusion, 22 Second protrusion, 23 Base section, 30 Individual electrode section, 31 First electrode, 32 Second electrode, 40 Heating section, 41 First heating section, 42 Second heating section, 50 Slit, 100 Thermal printer, 101 Control device, 102 Platen roller, 103 Winding device, 104 Power supply, 111 Calculation unit, 112 Memory unit, 201 Ink ribbon, 202 Paper.

Claims

1. circuit board and A common electrode is arranged on the surface of the substrate so as to extend in a first direction, A plurality of individual electrodes are arranged on the surface of the substrate in the first direction and are positioned at a predetermined distance from the common electrode in a second direction perpendicular to the first direction, The system comprises a plurality of heating elements, each positioned between the common electrode and the plurality of individual electrodes. The aforementioned plurality of individual electrodes are A plurality of first electrodes, each having a first value for the dimension in the first direction of the portion adjacent to the corresponding heating element, It includes a plurality of second electrodes, each of which has a second value, where the dimension in the first direction of the portion adjacent to the corresponding heating element is shorter than the first value, The plurality of individual electrodes are arranged in a thermal print head in a pattern in which a basic pattern in which one first electrode, two second electrodes, and one first electrode are arranged in this order in the first direction is repeated multiple times along the first direction.

2. The thermal print head according to claim 1, wherein the first value is substantially equal to the sum of a value greater than the second value and the dimension of the gap between adjacent individual electrodes in the first direction.

3. The aforementioned multiple heating elements are A plurality of first heating elements are disposed between the common electrode and the plurality of first electrodes, The thermal print head according to claim 1, comprising a plurality of second heating elements, each disposed between the common electrode and the plurality of second electrodes.

4. The thermal print head according to claim 3, wherein a slit portion extending in the second direction is formed in the center of at least one of the plurality of first heating elements in the first direction.

5. The thermal print head according to any one of claims 1 to 4, further comprising a driver circuit having a plurality of switching elements connected to each of the plurality of individual electrodes.

6. The thermal print head described in claim 5, A thermal printer comprising a control device that performs printing on a printing medium by controlling the state of the plurality of switching elements of the driver circuit and supplying power to the plurality of heating elements.

7. The control device is capable of switching between a first mode in which the printing resolution is a first resolution and a second mode in which the printing resolution is a second resolution lower than the first resolution. The control device is In the first mode, one dot is printed by making one switching element connected to one of the first electrodes, or two switching elements connected to two adjacent second electrodes, conduction. The thermal printer according to claim 6, wherein in the second mode, printing one dot is performed by making two switching elements, each connected to one adjacent first electrode and one adjacent second electrode, conductive.

8. The control device is In the first mode, the printing speed is set to a first speed, and the number of times power is applied per dot is set to one. The thermal printer according to claim 7, wherein in the second mode, the printing speed is maintained at the first speed, and the number of times power is applied per dot is two.

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