JP2019181819A - Thermal printer - Google Patents

Abstract

To reduce burden of adjustment in printing setting including printing density by a user.SOLUTION: A thermal printer includes: a thermal head in which a plurality of heating elements are arranged in a line in a direction orthogonal to a conveyance direction of a sheet developing colors by itself at a prescribed temperature or more and printing is performed by heating the heating elements and being brought into contact with the conveyed sheet; a temperature measurement section which measures a temperature in the vicinity of the sheet; and heating control section which heats the thermal head by the number of heating times of the first time per prescribed time and performs printing when the thermal head becomes almost even temperature slightly higher than a color developing temperature of the sheet on condition that the temperature measured by the temperature measurement section is determined to be a high temperature higher than a prescribed temperature, and heats the thermal head by the number of heating times of the second times which is less than the first time per prescribed time and performs printing when the thermal head becomes almost constant temperature slightly higher than the color developing temperature of the sheet on condition that the temperature measured by the temperature measurement section is determined to be a low temperature which is lower than the prescribed temperature.SELECTED DRAWING: Figure 8

Description

  Embodiments described herein relate generally to a thermal printer.

  2. Description of the Related Art Conventionally, there is a thermal printer that performs printing on a sheet such as a label using a thermal head in which heating elements are arranged in a line. In this type of thermal printer, the thermal head generates heat, and the paper is colored by applying heat to the paper conveyed by contacting the paper. In this way, the thermal printer prints on the paper.

  Recently, for example, products such as lunch boxes sold at convenience stores or the like are required to have a large label on which a lot of information related to the products is printed. When a large label is attached to a product, it becomes difficult to see the contents of the product. For this reason, recently, there is a label attached with a transparent paper so that the contents of the product can be understood even if a lot of information is printed. Such transparent paper is composed of, for example, a transparent film. When the thermal printer generates heat, the paper in contact with the thermal head is colored.

  By the way, for example, a paper such as a transparent paper has a high smoothness of the contact surface with the thermal head (smooth). Therefore, in such paper, the frictional force between the thermal head and the paper is high, especially in a humid environment, and the bite between the paper and the head is strong. There is a problem in that printing is not smoothly performed and print quality is impaired. In this humid environment, the environmental temperature is often high. The biting between the thermal head and the paper due to heat at the print location is called sticking.

  The problem to be solved by the present invention is to provide a thermal printer in which sticking hardly occurs even when the environmental temperature is high.

  In the thermal printer according to the embodiment, a plurality of heating elements are arranged in a line in a direction orthogonal to a conveyance direction of a sheet that develops a color by itself at a predetermined temperature or more, and the heating element generates heat to contact the sheet to be conveyed. A thermal head that performs printing, a temperature measuring unit that measures an environmental temperature near the paper, and the thermal head that has been determined that the temperature measured by the temperature measuring unit is higher than a predetermined temperature. Heat is generated at the first number of heat generations per predetermined time, the thermal head is printed at a substantially uniform temperature slightly higher than the coloring temperature of the paper, and the temperature measured by the temperature measuring unit is a low temperature lower than the predetermined temperature. The thermal head is caused to generate heat at a second number of times less than the first number per predetermined time on the condition that it is determined that And a heating control unit for printing the color temperature of the sheet at a substantially constant temperature slightly above.

FIG. 1 is a perspective view illustrating an example of an external configuration of a label printer according to the present embodiment. FIG. 2 is a diagram illustrating an example of a configuration of a printing mechanism housed in the label printer. FIG. 3 is a block diagram illustrating an example of a hardware configuration of the label printer. FIG. 4 is a memory map showing an example of a table for storing the number of strobes stored in the ROM of the label printer. FIG. 5 is a functional block diagram showing the functional configuration of the label printer. FIG. 6 is a diagram showing the relationship between the temperature of the thermal head and the number of strobes in a high temperature environment. FIG. 7 is a diagram showing the relationship between the temperature of the thermal head and the number of strobes in a low temperature environment. FIG. 8 is a flowchart showing the flow of control processing of the label printer.

  Hereinafter, embodiments of a printer will be described in detail with reference to the accompanying drawings. In the embodiment, an example in which the thermal printer is applied to a label printer that prints on a label will be described. In the embodiment, an example in which the paper is applied to a transparent label that is a transparent film-like label paper will be described.

  FIG. 1 is a diagram illustrating an example of an external configuration of a label printer according to the present embodiment. The label printer 1 shown in FIG. 1 includes a front panel 10a in a housing 10 and a display unit 11 and an operation unit 12 provided on the front panel 10a. The display unit 11 is configured by a display device such as a liquid crystal display. The operation unit 12 includes buttons 13 that are, for example, operation buttons for mode selection and operation buttons for instructing up / down / left / right. Further, the label printer 1 includes a printing mechanism 20 (see FIG. 2) inside, and a printed label is issued from a label issuing port 14 provided in one half 10b of the housing 10.

  The label printer 1 has a structure in which the printing mechanism 20 housed in the housing 10 is exposed by lifting the half 10b on one side of the housing 10 with two hinges 15 as fulcrums. The roll paper 90 (see FIG. 2) set in the printing mechanism 20 can be attached and detached. When the roll paper 90 is exchanged, the label printer 1 according to the present embodiment lifts the half half 10b. A large number of transparent labels 90 a attached to the mount are wound around the roll paper 90.

  FIG. 2 is a side view showing an example of the configuration of the printing mechanism 20 housed in the label printer 1. As shown in FIG. 2, the printing mechanism 20 includes a paper transport unit 21, a printing unit 22, a paper holding unit 23, and the like.

  The paper transport unit 21 mainly includes a paper transport roller 31, a support unit 32, a leaf spring 33, and a pinch roller 34. The paper transport roller 31 is rotatably attached to the frame 35a, and is rotated by the power of the transport motor 116 (see FIG. 3). The roll paper 90 is held by the paper holding unit 23.

  The support portion 32 is swingably attached to the frame 35b and supports the pinch roller 34 at one end. The pinch roller 34 is rotatably attached to one end of the support portion 32. The pinch roller 34 is provided at a position facing the paper transport roller 31. The plate spring 33 has one end attached to the frame 35 b and the other end in contact with the pinch roller 34. However, the pinch roller 34 is urged by the leaf spring 33 and pressed against the paper transport roller 31. The transparent label 90a drawn from the roll paper 90 is sandwiched between the paper transport roller 31 and the pinch roller 34 and transported in the direction of arrow P. The transparent label 90a is affixed continuously at equal intervals on a long mount.

  The printing unit 22 mainly includes a thermal head 41 and a platen 42. The thermal head 41 is fixed to a head holding portion 44 that is rotatably attached to the guide frame 25. The thermal head 41 is a line-type thermal printer head in which a large number of heating elements are arranged in a line. Each heating element generates heat when energized. When the heat of the heating element that has generated heat above the predetermined temperature is transferred to the transparent label 90a, the transparent label 90a at the position where the heat is transferred changes from a transparent color to a visible color (for example, black). That is, the transparent label 90a develops color on the condition that the thermal head 41 has reached a predetermined color development temperature or higher. The platen 42 is rotatably attached to the frame 35a and is rotated by the power of the platen motor 115 (see FIG. 3). A transparent label 90 a is sandwiched between the thermal head 41 and the platen 42. When the platen 42 rotates, the drawn transparent label 90a is conveyed in the direction of the label issuing port 14 described later. The thermal head 41 prints characters and figures by transferring heat to the transparent label 90a sandwiched between the platen 42 and the thermal head 41.

  A label peeling plate 51 is provided in the vicinity of the label issuing port 14. The label peeling plate 51 bends only the backing sheet at an acute angle just before discharging from the label issuing port 14, peels the transparent label 90 a from the mounting sheet, and discharges the peeled transparent label 90 a from the label issuing port 14. The mount from which the transparent label 90a has been peeled is wound around a winding shaft (not shown).

  The paper holding unit 23 is a shaft that holds the roll paper 90. The roll paper 90 is rotatably held by the shaft when the roll paper 90 is attached to the shaft which is the paper holding unit 23 through the core of the roll paper 90. The transparent label 90 a pulled out from the end of the roll paper 90 passes between the paper transport roller 31 and the pinch roller 34 and is sent to the printing unit 22 side by the rotation of the paper transport roller 31 and the pinch roller 34. In the printing unit 22, the transparent label 90 a passes between the platen 42 and the thermal head 41, is sent to the label issuing port 14, and the transparent label 90 a peeled off from the mount is discharged to the outside of the housing 10.

  A paper sensor 38 for detecting the position of the transparent label 90a is disposed on the transport path of the transparent label 90a. On the mount, the transparent labels 90a are arranged at equal intervals, and the gaps where the transparent labels 90a are not arranged are painted black. The paper sensor 38 is a reflective sensor, and receives light reflected by the blackened portion of the mount. Since the light is transmitted through the non-black portion of the mount, the paper sensor 38 does not receive the light. The paper sensor 38 detects whether the mount is black or not and whether it is black or not depending on whether light is received or not, and the transparent label 90a and the transparent label 90a are detected. Different output when not placed.

  Next, the hardware configuration of the label printer 1 will be described. FIG. 3 is a block diagram illustrating an example of a hardware configuration of the label printer 1. As shown in FIG. 3, the label printer 1 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, and the like. The CPU 101 becomes a control subject. The ROM 102 stores various programs. The RAM 103 expands programs and various data. The CPU 101, ROM 102, and RAM 103 are connected to each other via a bus 114. The CPU 101, the ROM 102, and the RAM 103 constitute the control unit 100. That is, the control unit 100 executes a control process related to the label printer 1 described later by the CPU 101 operating according to a control program stored in the ROM 102 and expanded in the RAM 103.

  The ROM 102 includes a strobe number unit 1021 described later with reference to FIG. The control unit 100 is connected to the communication I / F 105, the display controller 106, the operation unit controller 107, the head driver 108, the motor driver 109, the motor driver 110, the paper sensor controller 111, and the temperature sensor controller 112 via the bus 114. To do.

  The communication I / F 105 is connected to an external processing device (for example, a personal computer) via a wireless or wired communication line. The communication I / F 105 receives (inputs) print information to be printed on a transparent label from an external processing device. The display controller 106 is connected to the display unit 11 and controls display on the display unit 11. The operation unit controller 107 is connected to the operation unit 12 and receives a signal of the button 13 operated by the operation unit 12. The paper sensor controller 111 is connected to the paper sensor 38 and inputs information from the paper sensor 38. The temperature sensor controller 112 is connected to a temperature sensor 39 that is a temperature measurement unit. The temperature sensor 39 is provided at substantially the same position as the paper sensor 38 and measures the environmental temperature in the vicinity of the transparent label 90 a located on the conveyance path conveyed to the thermal head 41. The head driver 108 is connected to each heating element of the thermal head 41, and energizes the printing element to cause the heating element (that is, the thermal head 41) to generate heat. The motor driver 109 is connected to the platen motor 115 and controls the rotation of the platen motor 115. The motor driver 110 is connected to the transport motor 116 and controls the rotation of the transport motor 116.

  The RAM 103 includes a label storage unit 1031 and a temperature storage unit 1032. The label storage unit 1031 stores the paper type (for example, paper size and paper material) of the roll paper 90 mounted on the paper holding unit 23. The temperature storage unit 1032 stores the environmental temperature near the transparent label 90 a measured by the temperature sensor 39.

  Next, the strobe number unit 1021 will be described. FIG. 4 is a memory map showing an example of the strobe number unit 1021 that stores the number of strobes stored in the ROM 102 of the label printer 1. The strobe number section 1021 stores the strobe number for each of the three types of papers 1, 2, and 3 with different paper types. The type of paper varies depending on the thickness and material of the paper. The number of strobes is the number of times the heating element is heated within a predetermined time required for the thermal head to print one line of characters or figures. In other words, a transistor is connected to each heating element, and the number of strobes is the number of times the L signal and the H signal are alternately transmitted to the gate to each transistor within a predetermined time. When an L signal is input to the gate of each transistor, the transistor becomes conductive, and a voltage of 24 V, for example, is applied to the heat generating element to generate heat. In addition, when an H signal is input to the gate of each transistor, the transistor is cut off, no voltage is applied to the heating element, and the heating element stops generating heat and enters a non-heating state.

  When the environmental temperature in the vicinity of the transparent label 90a of the embodiment is high, the number of strobes A that is the first number of strobes is stored, and in the case where the environmental temperature in the vicinity of the transparent label 90a is lower than the high temperature, the number of strobes is stored. When B is stored and the environmental temperature in the vicinity of the transparent label 90a is a low temperature lower than the intermediate temperature, the strobe number C, which is the second number of strobes, is stored. The high temperature means that the environmental temperature near the transparent label 90a is, for example, 30 degrees or more. The medium temperature refers to, for example, an environmental temperature in the vicinity of the transparent label 90a of 10 degrees to less than 30 degrees. The low temperature means that the environmental temperature near the transparent label 90a is less than 10 degrees, for example. The strobe number A is larger than the strobe number B. Further, the strobe number B is larger than the strobe number C (third number). That is, the number of strobes at a high temperature is larger than the number of strobes at a medium temperature or a low temperature. Further, the number of strobes at the medium temperature is larger than the number of strobes at the low temperature.

  As the number of strobes increases, the thermal head 41 repeats a heat generation state and a non-heat generation state at shorter intervals. Therefore, heat hardly accumulates in the thermal head 41. As the number of strobes decreases, the heat generation state of the thermal head 41 becomes longer, and the non-heat generation state decreases accordingly, so that heat tends to accumulate in the thermal head 41.

  Further, when the environmental temperature in the vicinity of the paper 2 is high for the paper 2 which is opaque paper and has a high surface smoothness, the strobe number D is stored, and the environmental temperature in the vicinity of the paper 2 is higher than the high temperature. The strobe number E is stored when the temperature is low, and the strobe number F is stored when the environmental temperature near the sheet 2 is lower than the medium temperature. The strobe number D is larger than the strobe number E. Further, the strobe number E is larger than the strobe number F.

  Further, when the environmental temperature in the vicinity of the paper 3 is high with respect to the paper 3 which is an opaque paper and the surface smoothness is not as high as that of the paper 2, the strobe number G is stored, and the environment in the vicinity of the paper 3 is stored. When the temperature is an intermediate temperature lower than the high temperature, the strobe number H is stored, and when the environmental temperature near the sheet 3 is a low temperature lower than the intermediate temperature, the strobe number J is stored. The strobe number G is larger than the strobe number H. The strobe number H is larger than the strobe number J.

  Next, the functional configuration of the label printer 1 will be described. FIG. 5 is a functional block diagram showing the functional configuration of the label printer. As shown in FIG. 5, the control unit 100 functions as a temperature measurement unit 1001, a strobe extraction unit 1002, a heating control unit 1003, a print information input unit 1004, and a label determination unit 1005.

  The print information input unit 1004 determines whether print information is input to the communication I / F 105 from an external processing device. Further, the print information input unit 1004 stores the print information determined to be input to the communication I / F 105 in the RAM 103.

  The temperature measuring unit 1001 outputs the output from the temperature sensor 39 on condition that the print information is input to the print information input unit 1004 (that is, at the timing when the print information is input to the print information input unit 1004). Based on this, the ambient temperature near the paper is measured. The temperature measurement unit 1001 stores the measured ambient temperature near the paper in the temperature storage unit 1032.

  The strobe extraction unit 1002 is stored in the strobe number unit 1021 based on the environmental temperature measured by the temperature measurement unit 1001 and the information on the type of the roll paper 90 determined by the label determination unit 1005 and stored in the label storage unit 1031. Extract one strobe number. In the embodiment, the strobe extraction unit 1002 extracts the strobe number A on condition that the environmental temperature measured by the temperature measurement unit 1001 is high. The strobe extraction unit 1002 extracts the strobe number B on the condition that the environmental temperature measured by the temperature measurement unit 1001 is an intermediate temperature. The strobe extraction unit 1002 extracts the strobe number C on the condition that the environmental temperature measured by the temperature measurement unit 1001 is low.

  The label determination unit 1005 determines whether the roll paper 90 is set in the paper holding unit 23. The label determination unit 1005 determines the type of the roll paper 90 held by the paper holding unit 23. The label determination unit 1005 determines the type of the roll paper 90 based on the type of the roll paper 90 input from the operation unit 12. Alternatively, a sensor (not shown) determines the type of the roll paper 90 held by the paper holding unit 23, and the label determination unit 1005 determines whether the roll paper 90 held by the paper holding unit 23 is output by the output from the sensor. Determine the type. The label determination unit 1005 stores the determined type of the roll paper 90 in the label storage unit 1031.

  The heating control unit 1003 generates a strobe signal based on the extracted number of strobes, and controls the thermal head 41 to control printing on the paper. For example, when the environmental temperature stored in the temperature storage unit 1032 is 35 degrees and the type of the roll paper 90 stored in the label storage unit 1031 is the transparent label 90a, the heating control unit 1003 A strobe signal is generated based on the strobe number A extracted by the extraction unit 1002, and the thermal head 41 is controlled to perform printing on the transparent label 90a.

  The heating control unit 1003 generates a strobe signal based on the strobe number A, and performs one line printing on the transparent label 90a as shown in FIG. As shown in FIG. 6, among the heating elements arranged in the thermal head 41, the strobe signal applied to the gate terminal of the transistor connected to the heating element used for printing is H signal at timing 1 based on the printing signal. To L signal. Then, a current flows through the heating element, and the heating element starts to generate heat. Eventually, at timing 2, the temperature of the thermal head 41 (that is, the heating element) exceeds the coloring temperature at which the transparent label 90a develops color. The time T1 required from the timing 1 to the timing 2 is an empirically determined time based on the environmental temperature in the vicinity of the transparent label 90a and the number of heat generating elements.

  At timing 3 when the temperature rise curve of the thermal head 41 of the heating element becomes gentle after timing 2, the strobe signal repeats the H signal and the L signal at a predetermined time T3. In the example of FIG. 6, the H signal and the L signal are repeated six times at an interval of a predetermined time T3. These six times correspond to the first number of times. Note that the time T2 required from the timing 1 to the timing 3 at which the temperature of the thermal head 41 becomes gentle is an empirically determined time depending on the environmental temperature in the vicinity of the transparent label 90a and the number of heat generating elements. The temperature of the thermal head 41 is an estimated value. That is, the heating control unit 1003 performs printing for the first number of times on condition that the temperature of the thermal head 41 is equal to or higher than the color development temperature of the transparent label 90a.

  At timing 3, the number of strobes A repeats the H signal and the L signal at intervals of time T3, so that the temperature of the thermal head 41 changes at a substantially constant temperature slightly exceeding the coloring temperature of the transparent label 90a.

  The heating control unit 1003 generates the strobe signal in FIG. 6 based on the strobe number A. Then, the heating control unit 1003 performs strobe control of the heat generation of the heating elements of the thermal head 41 based on the generated strobe signal. Specifically, the heating control unit 1003 causes the thermal head 41 to generate heat at the timing 1 with the strobe signal as an L signal. Then, the heating control unit 1003 executes the strobe control that switches the strobe signal between the H signal and the L signal at an interval of the time T3 when the time T2 elapses. The heating control unit 1003 repeats switching between the H signal and the L signal for the first number of times. Meanwhile, the temperature of the thermal head 41 is kept substantially constant at a temperature slightly higher than the coloring temperature, and the thermal head 41 does not reach a temperature higher than the maintained temperature. Therefore, sticking does not occur between the thermal head 41 and the transparent label 90a. Thereafter, at timing 4, the heating control unit 1003 sets the strobe signal as an H signal and ends the printing process for one line. Then, the temperature of the thermal head 41 is lowered to less than the color development temperature.

  For example, when the environmental temperature stored in the temperature storage unit 1032 is 5 degrees and the type of the roll paper 90 stored in the label storage unit 1031 is the transparent label 90a, the heating control unit 1003 Then, the strobe number C is extracted. Then, the heating control unit 1003 controls the thermal head 41 based on the extracted strobe number C and performs printing on the transparent label 90a.

  The heating control unit 1003 generates a strobe signal based on the strobe number C, and performs printing on the transparent label 90a as shown in FIG. As shown in FIG. 7, the strobe signal applied to the gate terminals of the transistors connected to the heating elements arranged in the thermal head 41 changes from the H signal to the L signal at timing 1. Then, a current flows through the heating element, and the heating element starts to generate heat. Eventually, at timing 5, the temperature of the thermal head 41 (that is, the heating element) exceeds the coloring temperature at which the transparent label 90a develops color. The time T4 required from the timing 1 to the timing 5 is an empirically determined time based on the environmental temperature in the vicinity of the transparent label 90a and the number of heat generating elements.

  At timing 6 when the temperature rising curve of the thermal head 41 of the heating element becomes gentle after the timing 5 has elapsed, the strobe signal outputs an H signal for a time T3, and then for a time T6 longer than the time T3. L signal is output. For example, time T6 is twice as long as time T3. The output of the H signal during time T3 and the output of the L signal during time T6 are repeated. In the example of FIG. 7, the process is repeated three times. These three times correspond to the second number of times. Note that the time T5 required from the timing 1 to the timing 6 at which the temperature of the thermal head 41 becomes gentle is an empirically determined time depending on the environmental temperature in the vicinity of the transparent label 90a and the number of heat generating elements. That is, the heating control unit 1003 performs printing for the second number of times on the condition that the temperature of the thermal head 41 is equal to or higher than the color development temperature of the transparent label 90a.

  At timing 6, the temperature of the thermal head 41 is kept substantially constant at a temperature slightly higher than the coloring temperature by repeating the H signal and the L signal at the interval of the predetermined time T3 and the predetermined time T6. . In this case, although the time T6 during which the thermal head 41 generates heat is longer than the time T3 when the heat generation is stopped, the temperature of the thermal head 41 is maintained at a substantially constant temperature in the vicinity of the transparent label 90a. This is because the environmental temperature is lower than the example of FIG.

  The heating control unit 1003 generates the strobe signal in FIG. 7 based on the strobe number C. The heating control unit 1003 controls the heat generation of the heating elements of the thermal head 41 based on the generated strobe signal. Specifically, the heating control unit 1003 causes the thermal head 41 to generate heat at the timing 1 with the strobe signal as an L signal. Then, the heating control unit 1003 executes the strobe control for switching the strobe signal between the H signal and the L signal at intervals of the time T3 and the time T6 at the timing 6 when the time T5 has elapsed. The heating control unit 1003 repeats switching between the H signal and the L signal for the second number of times. In the meantime, the temperature of the thermal head 41 is maintained at a substantially constant temperature, and the thermal head 41 does not reach a temperature higher than the maintained temperature. Therefore, sticking does not occur between the thermal head 41 and the transparent label 90a. Thereafter, at timing 7, the heating control unit 1003 sets the strobe signal as an H signal and ends the printing process for one line. Then, the temperature of the thermal head 41 is lowered to less than the color development temperature. Timing 4 and timing 7 are the same timing.

  For example, when the environmental temperature stored in the temperature storage unit 1032 is 15 degrees and the type of the roll paper 90 stored in the label storage unit 1031 is the transparent label 90a, the heating control unit 1003 Extract the strobe number B. Then, the heating control unit 1003 controls the thermal head 41 based on the extracted strobe number B (third number) and performs printing on the transparent label 90a.

  In addition, the strobe number extraction unit performs the number of strobes corresponding to the paper 2 (strobe number D, strobe number E, strobe number F) and the number of strobes corresponding to the paper 3 (strobe number G, strobe number H, strobe number J). Is extracted, the strobe control corresponding to the number of strobes is executed.

  Next, the control process of the label printer 1 will be described. FIG. 8 is a flowchart showing the flow of control processing of the label printer 1. As shown in FIG. 8, the label determination unit 1005 determines whether the roll paper 90 is set in the paper holding unit 23 (S11). When the label determination unit 1005 determines that the roll paper 90 is set in the paper holding unit 23 (Yes in S11), the label determination unit 1005 determines the type of the roll paper 90 held in the paper holding unit 23. Is determined (S12). Subsequently, the label determination unit 1005 stores the determined type of the roll paper 90 in the label storage unit 1031 (S13). After the process of S13 or when the label determination unit 1005 determines that the roll paper 90 is not set (No in S11), the print information input unit 1004 sends the print information from the external processing device to the communication I / F 105. Is determined (S14). When the print information input unit 1004 determines that the print information is input from the external processing device to the communication I / F 105 (Yes in S14), the print information input unit 1004 stores the input print information in the RAM 103. . When it is determined that the print information is input to the print information input unit 1004, the temperature measurement unit 1001 measures the environmental temperature near the transparent label 90a based on the output from the temperature sensor 39 (S15). In other words, when print information is not input to the print information input unit 1004, the temperature measurement unit 1001 does not measure the environmental temperature near the transparent label 90a.

  Next, the strobe extraction unit 1002 uses the environmental temperature measured by the temperature measurement unit 1001 and the type information of the roll paper 90 (transparent label 90a in the embodiment) determined by the label determination unit 1005 and stored in the label storage unit 1031. Based on this, one strobe number stored in the strobe number section 1021 is extracted (S16).

  Next, the heating control unit 1003 generates a strobe signal based on the extracted number of strobes, and controls the thermal head 41 to perform printing on the transparent label 90a (S18).

  As described above, in the label printer 1 according to the embodiment, a plurality of heating elements are arranged in a line in a direction orthogonal to the transport direction of the transparent label 90a, and printing is performed on the transparent label 90a that is transported by heating the heat generating elements. When it is determined that the thermal head 41, the temperature measuring unit 1001 that measures the environmental temperature near the transparent label 90a, and the environmental temperature measured by the temperature measuring unit 1001 are higher than a predetermined temperature (for example, 30 degrees), The thermal head 41 is heated at the first number of heat generations per predetermined time, and the thermal head 41 is printed at a substantially uniform temperature slightly higher than the coloring temperature of the transparent label 90a, and the environmental temperature measured by the temperature measuring unit 1001 is When it is determined that the temperature is lower than a predetermined temperature (for example, 5 degrees), the thermal head 41 is less than the first number per predetermined time. By heating at a frequency of fever second number, and a, and a heating control unit that performs almost printing as constant temperature slightly above the color temperature of the transparent label 90a of the thermal head 41.

  Therefore, in the label printer 1 of the embodiment, even when the environmental temperature is high (high temperature), sticking hardly occurs between the thermal head 41 and the transparent label 90a.

  As mentioned above, although embodiment of this invention was described, this embodiment is shown as an example and is not intending limiting the range of invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment is included in the scope and gist of the invention, and is also included in the invention described in the claims and the equivalent scope thereof.

  For example, in the embodiment, the transparent label is described as an example of paper. However, the present invention is not limited to this, and paper other than the transparent label may be used.

  In the embodiment, the heating control unit 1003 performs the strobe control at the timing 3 or the timing 6 when the temperature of the thermal head 41 becomes equal to or higher than the coloring temperature. However, the present invention is not limited to this, and the heating control unit 1003 may start the strobe process at a timing when the temperature of the thermal head 41 becomes equal to or higher than a predetermined temperature slightly lower than the coloring temperature. The timing at which the temperature of the thermal head 41 becomes equal to or higher than a predetermined temperature slightly lower than the color development temperature is determined based on empirical rules.

  In the embodiment, the strobe number unit 1021 stores a medium temperature strobe number in addition to a high temperature and a low temperature. When the environmental temperature near the transparent label 90a is an intermediate temperature, the strobe control is executed with the number of strobes corresponding to the intermediate temperature. However, the present invention is not limited to this, and the present invention includes those that do not store the number of strobes for medium temperature and execute strobe control for high temperature and strobe control for low temperature. Further, the medium temperature may not be set at the environmental temperature, and two types of high temperature above a predetermined temperature and low temperature lower than the predetermined temperature may be used.

  In the embodiment, the label printer 1 has been described as an example of a thermal printer. However, the thermal printer may be a thermal transfer printer other than the label printer 1.

DESCRIPTION OF SYMBOLS 1 Label printer 41 Thermal head 90a Transparent label 100 Control part 1001 Temperature measurement part 1002 Strobe extraction part 1003 Heating control part 1004 Print information input part 1005 Label judgment part 1021 Strobe number part 1031 Label storage part 1032 Temperature storage part

JP 2001-96789 A

Claims (6)

A thermal head in which a plurality of heating elements are arranged in a line in a direction orthogonal to the conveyance direction of the paper that develops color at a predetermined temperature or higher, and prints in contact with the paper conveyed by heating the heating elements;
A temperature measuring unit for measuring an environmental temperature in the vicinity of the paper;
On the condition that the temperature measured by the temperature measuring unit is determined to be a high temperature equal to or higher than a predetermined temperature, the thermal head is heated at a first number of heat generations per predetermined time, and the thermal head is moved to the sheet. Printing is performed at a substantially uniform temperature slightly higher than the coloring temperature, and on the condition that the temperature measured by the temperature measuring unit is determined to be a low temperature lower than a predetermined temperature, the thermal head is moved the first number of times per predetermined time. A heating control unit that generates heat at a second number of heat generations that is less frequent and prints the thermal head at a substantially constant temperature slightly above the color development temperature of the paper;
With thermal printer. A print information input unit for inputting print information to be printed on the paper using the thermal head;
The temperature measurement unit measures the temperature near the paper on condition that the print information input unit has input print information;
The thermal printer according to claim 1. The paper itself develops color on the condition that the thermal head has reached a predetermined color development temperature or more,
The heating control unit performs printing at the first number or the second number on the condition that the temperature of the thermal head is equal to or higher than the coloring temperature.
The thermal printer according to claim 1 or 2. The paper itself develops color on the condition that the thermal head has reached a predetermined color development temperature or more,
The heating control unit performs printing at the first number or the second number on the condition that the temperature of the thermal head is equal to or higher than a predetermined temperature slightly lower than the color development temperature.
The thermal printer according to claim 1 or 2. The second number is zero.
The thermal printer as described in any one of Claims 1 thru | or 4. The heating control unit changes the first number of times and the second number of times according to the type of the paper.
The thermal printer as described in any one of Claims 1 thru | or 5.

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