JP2013202950A - Printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent inconvenience due to the excessive high temperature of a thermal head while coping with high or low sensitivity of a print layer and high or low print density.SOLUTION: A printer 1 includes a platen roller 111 transporting roll paper S having a thermosensitive layer developing color, a roller driving circuit 244 for driving the platen roller 111, a thermal line head 112 performing printing on the transported roll paper S, a head driving circuit 243 for controlling energization of a plurality of heating elements of the thermal line head 112, and a temperature sensor 151 for detecting a temperature of the thermal line head. When the temperature detected by the temperature sensor 151 is raised and reaches a printing stop temperature T1, printing processing is stopped, and a high or low printing stop temperature T1 is changed and set in accordance with high or low print density D set in printing processing.

Description

  The present invention relates to a printing apparatus that forms a desired print using a thermal head.

  A printing apparatus that forms a desired print using a thermal head is already known (see, for example, Patent Document 1). In this conventional printing apparatus, heat is applied to the print medium (thermal paper) conveyed by the conveying means (platen roller) by the heating element of the thermal head. As a result, the heat-sensitive layer of the printing medium is colored to form a desired print (printing process).

  Here, when printing is performed by the thermal head, the temperature of the thermal head increases as the printing process is continuously or repeatedly executed. When the temperature of the thermal head becomes excessively high, inconvenience due to overheating may occur. In this prior art, attention is paid to the deterioration of the durability of the thermal head as an example of the inconvenience. That is, the above-described conventional printing apparatus is provided with temperature detection means (thermistor) for detecting the temperature of the thermal head. Then, when the temperature of the thermal head detected by the temperature detecting means reaches a predetermined temperature (a temperature set in advance for preventing durability deterioration), the printing process is stopped.

JP 2004-25512 A

  However, when the thermal head becomes excessively hot as described above, there may be another inconvenience other than the above-described deterioration in durability. That is, when the thermal head reaches the color development temperature of the thermal layer of the printing medium (or the transfer temperature of the ink when the transfer is performed from the ink ribbon to the transfer layer, the same applies hereinafter) Regardless of the above, there is a risk of erroneous color development (or erroneous ink transfer) of the heat-sensitive layer. In the prior art described above, consideration was given to durability deterioration due to overheating of the thermal head as described above, but no special consideration was given to the erroneous color development or erroneous transfer as described above.

  On the other hand, a plurality of types of printing media having different color development sensitivities (or ink transfer sensitivities) of the thermosensitive layer may be used as printing media. In such a case, for example, when a printing medium having a relatively high sensitivity printing layer (heat-sensitive layer or transfer layer) is used, good color development (or transfer) can be obtained even at a relatively low temperature. Therefore, normally, the energy applied to the heating element is set to be small (in other words, the print density is low). Conversely, when a printing medium having a relatively low-sensitivity printing layer (heat-sensitive layer or transfer layer) is used, good color development (or transfer) cannot be obtained unless the temperature is set at a relatively high temperature. Usually, the energy applied to the heating element is set to be large (in other words, the print density is high). As described above, the level of the print density and the level of the sensitivity of the layer to be printed usually have a correlation.

  As a result, in order to prevent the printing layer from reaching the color development temperature (or transfer temperature) as described above, for example, the printing layer is provided with a relatively high sensitivity (in other words, the printing density is set lower). When a printing medium is used, it is necessary to stop the printing process at a relatively low temperature. On the other hand, for example, when a printing medium having a printing layer having a relatively low sensitivity (in other words, the printing density is set high) is used, it is sufficient to stop the printing process after continuing the printing process to a relatively high temperature. . In the prior art described above, no particular consideration has been given to the influence on the temperature control of the thermal head due to the high or low sensitivity of the printing layer and the high or low printing density.

  An object of the present invention is to provide a printing apparatus that can reliably prevent inconvenience due to an excessively high temperature of a thermal head while corresponding to high and low sensitivity of a printing layer and high and low printing density.

  In order to achieve the above object, the present invention provides a conveying means for conveying a printing medium comprising a printing layer comprising a heat-sensitive layer that develops color by receiving a predetermined amount of heat or a transfer layer that receives thermal transfer from an ink ribbon. And a driving means for driving the conveying means, a plurality of heating elements, a thermal head for printing on the printing medium conveyed by the conveying means, and a plurality of the heating elements of the thermal head. Energizing means for controlling energization, and a printing apparatus for executing a printing process for forming a desired print on the printing medium, the temperature detecting means for detecting the temperature of the thermal head, and the printed matter When the temperature detected by the temperature detecting means rises and reaches the limit temperature with the creation, the driving means and the energizing means are linked so that the printing process is stopped. The density control means for setting the print density in the printing process by variably setting the energy applied to the heat generating element by the stop control means, the density setting means, and the density setting means. And a limiting temperature setting means for setting the limiting temperature by changing it between high and low according to the print density.

  In the printing apparatus of the present invention, heat is applied to the print medium conveyed by the conveying means by the heating element of the thermal head. As a result, the heat-sensitive layer as the print layer of the print medium develops color, or the ink thermal transfer from the ink ribbon is performed on the transfer layer as the print layer, and a print process for forming a desired print is executed. Is done. As the printing process is continuously or repeatedly executed, the temperature of the thermal head increases. When the temperature of the thermal head becomes excessively high, various inconveniences may occur.

  As an example of the inconvenience, when the thermal head reaches the color development temperature (or ink transfer temperature) of the heat sensitive layer of the printing medium, the erroneous color development of the heat sensitive layer (or the ink of the ink) regardless of the formation of the desired print. Erroneous transfer) may occur. In order to prevent this, it is necessary to stop the printing process before the temperature of the thermal head reaches the color development temperature (or transfer temperature). Therefore, in the present invention, the temperature of the thermal head is detected by the temperature detection means, and the print processing is stopped by the stop control means when the detected temperature reaches the limit temperature.

  In the present invention, the limit temperature at which the stop control means stops the printing process is variable. That is, the limit temperature is changed between high and low depending on whether the print density is set higher or lower by the density setting means that variably sets the energy applied from the energization means to the heating element. Is set. Accordingly, when a printing medium having a high-sensitivity printing layer is used, the printing process can be surely stopped at a low temperature by using a lower limit temperature. Conversely, when a printing medium having a low-sensitivity printing layer is used, the printing process can be continued without stopping to a relatively high temperature while using a higher limit temperature. As a result, it is possible to avoid inconveniences caused by excessively high temperature of the thermal head while sufficiently responding to the high / low sensitivity of the print layer and the corresponding high / low print density settings.

  According to the present invention, it is possible to reliably prevent inconvenience due to an excessively high temperature of the thermal head while dealing with high and low sensitivity of the printing layer and high and low printing density.

1 is a system configuration diagram illustrating a print processing system including a printer according to an embodiment of the present invention. 1 is a perspective view illustrating a schematic configuration of a printer. FIG. 3 is a perspective view of the printer shown in FIG. 2 as viewed obliquely from above in a state where the top cover of the housing is removed. It is sectional drawing by the FF cross section in FIG. 2, and sectional drawing by a GG cross section. It is a functional block diagram showing the control system of an external terminal and a printer. 6 is a flowchart illustrating a control procedure executed by the CPU of the printer. It is a table showing the setting of printing stop temperature according to printing density.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

<Print processing system>
A print processing system including the printer of this embodiment will be described with reference to FIG.

  In FIG. 1, in this print processing system LS, an external terminal 400 for operating the printer 1 (printing apparatus) and the printer 1 for executing printing corresponding to the print data received from the external terminal 400 are In the example, they are connected by a USB (Universal Serial Bus) cable 9.

  The external terminal 400 is, for example, a general-purpose personal computer that is generally commercially available, and includes a display unit 401 such as a liquid crystal display and an operation unit 402 such as a keyboard and a mouse. In addition, a host socket 419 (see FIG. 5 described later) to which the first connector 9H at the end of the USB cable 9 is detachably attached is provided at an appropriate location (for example, the back portion) of the external terminal 400. Yes.

  The side surface of the printer 1 is provided with a target socket 109 (see FIG. 3 to be described later) on which the second connector 9T at the end opposite to the first connector 9H of the USB cable 9 is detachably attached. Yes.

  The USB cable 9 is the first connector 9H (for example, a USB connector which is a so-called series A plug) that causes the connecting device to function as a host, and the second connector 9T (for example, a so-called series B plug) that allows the connecting device to function as a target. USB connectors) (see each enlarged view in FIG. 2). In this example, the USB cable 9 has a second connector 9T attached (connected) to the target socket 109 of the printer 1 (with an internal USB port), and is connected to the host socket 419 of the external terminal 400. One connector 9H is attached.

<Printer configuration>
Next, the configuration of the printer 1 will be described with reference to FIGS. 2 to 4, the lower right direction in FIG. 2 is defined as right, the upper left direction is defined as left, the upper right direction is defined as rear, the lower left direction is defined as forward, the upper direction is defined as upward, and the lower direction is defined as downward. (Refer to the illustration of arrows in each figure).

  As shown in FIGS. 2 to 4, the printer 1 includes a substantially box-shaped casing 100 that constitutes the outline of the apparatus. The housing 100 includes a top cover 101 that constitutes the upper part of the apparatus outer shell and an under cover 102 that constitutes the lower part of the apparatus outer shell. The top cover 101 includes a fixed portion 101A and an opening / closing lid 101B.

  A roll storage unit 161 is provided below the opening / closing lid 101B of the top cover 101 (inside the housing 100) (see FIGS. 3 and 4). In this roll storage portion 161, roll paper S (print medium) is rotatably supported at both ends by a support member 162 (see FIG. 3), and thus, continuously from the roll storage portion 161. The roll paper S can be supplied. At this time, the opening / closing lid 101B is rotatably connected to the rear end portion of the under cover 102 through the hinge portion H, and the roll storage portion 161 is exposed to the outside of the apparatus by opening the opening / closing lid 101B. Thus, the roll paper S can be easily mounted or replaced. A discharge port 107 for discharging the printed roll paper S is provided at a substantially central portion of the top cover 101 in the front-rear direction.

  A platen roller 111 (conveying means; see FIG. 4) is rotatably supported at the front end of the opening / closing lid 101B. The platen roller 111 conveys the roll paper S when the opening / closing lid 101B is in the closed state.

  A thermal line head 112 (thermal head; see FIGS. 3 and 4) is provided to contact the platen roller 111 with a predetermined pressure contact force with the roll paper S conveyed as described above. At this time, the roll paper S is provided with a heat-sensitive layer (printed layer) that develops color by receiving a predetermined amount of heat on the surface on the thermal line head 112 side, although detailed illustration is omitted. When a plurality of heating elements (not shown) provided in the thermal line head 112 are driven by a head drive circuit 243 (see FIG. 5 described later) to generate heat, the heat sensitive layer is formed by receiving a predetermined amount of heat from the heating elements. Color develops. As a result, a desired print is formed on the roll paper S by the thermal line head 112.

  At this time, a driving motor that generates a driving force for rotationally driving the platen roller 111 is provided in the housing 100. When the open / close lid 101B is closed, the driving force of the motor is driven by a gear mechanism (not shown). It is transmitted to the platen roller 111. The drive of the drive motor is controlled by a roller drive circuit 244 (see FIG. 5 to be described later) provided on a control board 170 (see FIG. 4A) disposed behind the housing 100. . Below the control board 170 in the housing 100, a battery power storage unit 163 (see FIG. 4A) in which a battery power is inserted from the lower surface side of the under cover 102 is provided.

<Overview of printer operation>
In the above configuration, at the time of printing, print data is transmitted from the external terminal 400 to the printer 1 via the USB cable attached to the target socket 109 (see FIG. 3) provided on the under cover 102. Further, the roll paper S is fed out from the roll storage portion 161 by the rotation of the platen roller 111 based on the driving force of the driving motor. The fed roll paper S is inserted between the thermal line head 112 and the platen roller 111, and printing of a desired mode based on the print data is performed on the roll paper S by the heating element of the thermal line head 112. Done. The printed roll paper S is discharged from the discharge port 107 to the outside of the housing 100. At this time, fixed teeth 160 are attached to the main chassis member 150 (see FIG. 3) provided in the housing 101 so as to follow the discharge port 107 inside the discharge port 107. The operator can manually cut the end portion of the roll paper S that has been printed as described above and discharged from the discharge port 107 using the fixed teeth 160.

<Electrical configuration>
Next, the electrical configurations of the external terminal 400 and the printer 1 having the above-described configuration will be described with reference to FIG.

<Electrical configuration of printer>
As shown in FIG. 5, the printer 1 stores a CPU 231 that controls the entire apparatus, a control program (including a print processing program for executing processing shown in FIG. 6 described later), and the like, and is rewritable. FLASH ROM 234, which is a non-volatile storage element that does not lose data even when the power is turned off, SRAM 233, which is a volatile storage element in which temporary data generated when CPU 231 executes a control program, and printer 1 and EEPROM 235 which is a non-volatile storage element that stores parameter information, history information, a table shown in FIG. The CPU 231 is connected to each other via a bus so that information stored in the FLASH ROM 234, the SRAM 233, and the EEPROM 235 can be referred to.

  The printer 1 also includes an input / output interface 236. The input / output interface 236 is inserted between the CPU 231 and various devices connected to the CPU 231 (a head drive circuit 243, a roller drive circuit 244, a USB controller 242, a temperature sensor 151, and a paper sensor 152 described later). Then, by performing voltage conversion processing between input and output signals, impedance conversion processing, timing adjustment processing, etc., signals output from the CPU 231 to the various devices can be recognized by various devices, and from various devices. A signal transmitted to the CPU 231 can be recognized by the CPU 231.

  The printer 1 also includes the head drive circuit 243 (energization unit) that can control the energization of the heat generating element of the thermal line head 112. The head drive circuit 243 is electrically connected to the thermal line head 112 so as to control the thermal line head 112 and print data on the roll paper S. The head driving circuit 243 is electrically connected to the input / output interface 236 so that the CPU 231 can control the head driving circuit 243.

  Although not shown in FIGS. 1 to 4, a temperature sensor 151 (temperature detection means) having a known configuration capable of detecting the temperature of the thermal line head 112 is provided at this time. The detection result of the temperature sensor 151 is input to the CPU 231 via the input / output interface 236.

  The printer 1 also includes a roller drive circuit 244 (drive means) that can control the drive of the platen roller 111 by the drive motor. The roller drive circuit 244 is electrically connected to the drive motor so that the roll paper S can be conveyed by controlling the platen roller 111 when printing data on the roll paper S by the thermal line head 112. Yes. The roller drive circuit 244 is electrically connected to the input / output interface 236 so that the CPU 231 can control the roller drive circuit 244.

  The printer 1 also includes a USB controller 242. The USB controller 242 is a controller device for performing voltage conversion processing and impedance conversion processing so that communication with the external terminal 400 can be performed via the USB cable 9 attached to the target socket 109. The signal received from the external terminal 400 via the USB cable 9 can be recognized by the CPU 231, or the signal transmitted from the CPU 231 can be transmitted to the external terminal 400 via the USB cable 9. As described above, the USB controller 242 and the input / output interface 236 are electrically connected.

  The CPU 231, SRAM 233, FLASH ROM 234, EEPROM RPM 235, head drive circuit 243, roller drive circuit 244, USB controller 242, etc. are provided on the control board 170.

<Electrical configuration of external terminal>
Next, the electrical configuration of the external terminal 400 will be described. The external terminal 400 includes a CPU 410 that performs overall control, a ROM 403 that stores a BIOS program that is read when the CPU 410 is activated, a hard disk drive (HDD) 406 that stores an execution file of an OS and applications, and the CPU 410. The RAM 404 and the like, which are volatile storage elements that store temporary data and the like necessary when the OS and applications are executed. The CPU 410 is connected to the CPU 410 via the bus 409 so that the information stored in the ROM 403, RAM 404, and HDD 406 can be referred to by the CPU 410.

  The external terminal 400 includes a display control unit 407. The display control unit 407 includes a display RAM (not shown) for storing display data. The display control unit 407 is electrically connected to the display unit 401 to transmit a control signal to the display unit 401 to display the display data. It is connected. In addition, the display control unit 407 is electrically connected to the bus 409 so that display control from the CPU 410 is possible.

  The external terminal 400 includes a USB controller 408. The USB controller 408 is a controller device for performing voltage conversion processing and impedance conversion processing so that a peripheral device can communicate with the CPU 410 via the USB interface. In the example shown in FIG. 5, the printer 1 is connected to the USB controller 408 via the USB cable 9 attached to the host socket 419, and the operation unit 402 is also connected to the USB controller 408. . The USB controller 408 and the bus 409 are electrically connected so that the operation content of the operation unit 402 can be detected by the CPU 410 and communication between the printer 1 and the CPU 410 is possible. .

<Features of this embodiment>
As described above, the present embodiment is characterized in that the printing process is stopped when the temperature sensor 151 detects an excessively high temperature state of the thermal line head 112. Hereinafter, the details will be described in order.

<Preventing miscoloration due to high temperatures>
As described above, in the printer 1 of the present embodiment, heat is applied to the roll paper S conveyed by the platen roller 111 by the heating elements of the thermal line head 112, and the above-mentioned heat-sensitive layer of the roll paper develops color and is desired. Is formed. As the printing process is continuously or repeatedly executed, the temperature of the thermal line head 112 increases.

  When the temperature of the thermal line head 112 becomes excessively high and reaches the coloring temperature of the heat sensitive layer, there is a possibility that erroneous color development of the heat sensitive layer may occur regardless of the formation of the desired print. In the present embodiment, in order to prevent this, the printing process is stopped when the temperature of the thermal line head 112 detected by the temperature sensor 151 reaches a printing stop temperature (details will be described later) variably set in advance. (Refer to the flow of FIG. 6 described later).

<Relationship between print density and color temperature>
Here, in the printer 1 of the present embodiment, a plurality of types of roll paper S having different color development sensitivities of the thermosensitive layer can be used. In such a case, for example, when a roll paper S having a relatively high-sensitivity heat-sensitive layer is used, good color development can be obtained even at a relatively low temperature. Is set. Conversely, when roll paper S having a relatively low-sensitivity heat-sensitive layer is used, good color development cannot be obtained unless the temperature is set to a relatively high temperature. (If the print density is high).

  In the present embodiment, the magnitude setting of the energy to the heating element is performed in the form of “print density setting”. That is, the operator can manually set the print density D to 10 levels through the operation unit 402 of the external terminal 400 (see FIG. 7 described later). If the print density D is set low, the energy applied to the heat generating element of the thermal line head 112 becomes smaller. If the print density D is set high, the energy applied to the heat generating element of the thermal line head 112 increases. . Therefore, in the present embodiment, when the roll paper S having a relatively low-sensitivity heat-sensitive layer is mounted on the roll storage unit 161 by itself, the operator manually operates the operation unit 402 to increase the print density D. Set to. On the contrary, when the roll paper S having a relatively high sensitivity heat-sensitive layer is mounted on the roll storage unit 161 by itself, the operator manually operates the operation unit 402 to set the print density D low.

  As described above, the level of print density D and the level of sensitivity of the heat sensitive layer are usually correlated. As a result, when the stop control of the printing process is performed before the heat-sensitive layer reaches the color development temperature as described above, in the case of the roll paper S having a relatively high-sensitivity heat-sensitive layer (in other words, the print density D is set by the operator). If it is set lower), it is necessary to stop the printing process at a relatively low temperature. Conversely, for example, in the case of the roll paper S having a relatively low-sensitivity heat-sensitive layer (in other words, when the print density D is set higher by the operator), after the printing process is continued to a relatively high temperature, It is enough to stop.

<Control details>
In the present embodiment, from the above viewpoint, the temperature at which the printing process is stopped as described above is variably set according to the print density D. Hereinafter, the control executed by the CPU 231 of the printer 1 based on the print processing program in order to realize this technique will be described with reference to FIGS. 6 and 7.

  In the flow shown in FIG. 6, for example, this flow is started when the operator gives a print start instruction through an appropriate operation of the operation unit 402 of the external terminal 400. First, in step S110, the CPU 231 determines whether or not the print density D has been set by the operator via the operation unit 402. As described above, in this example, the operator sets the print density D in 10 stages of D = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 (see FIG. 7 described later). Can be set. As the value of the print density D increases (closer to 10), the energy applied to the heating element of the thermal line head 112 increases, and the color development in the heat sensitive layer of the roll paper S increases. The smaller the value of the print density D (closer to 1), the smaller the energy applied to the heating element of the thermal line head 112, and the color development on the heat sensitive layer of the roll paper S becomes lighter.

  While the print density D is not manually set by the operator, the determination in step S100 is not satisfied (S100: NO), and a loop standby is performed. When the operator manually sets the print density D, the determination at Step S100 is satisfied (S100: YES), and the routine goes to Step S105. The step S100 functions as a density instruction acquisition unit described in each claim. Note that the operator may perform the density setting input operation by an operation unit separately provided in the printer 1 instead of the density setting input operation by the external terminal 400 as described above.

  In step S105, the CPU 231 sets the D setting value (any integer value from 1 to 10) input from the operation unit 402 of the external terminal 400 in step S100 as the print density setting value. This step S105 functions as the density setting means described in each claim. Thereafter, the process proceeds to step S110.

  In step S110, the printing stop temperature T1 for stopping the printing process and the restarting temperature T2 for restarting the printing process after the stop are set according to the printing density D set in step S105. This setting is performed using the table shown in FIG. 7A previously stored in the EEPROM 235 according to the magnitude of the print density D (the table shown in FIG. 7B as described later). May be used).

  As shown in FIG. 7A, in this table, the print stop temperature T1 and the restart temperature T2 corresponding to each value of the print density D are defined. In this example, the energization time t of the corresponding thermal line head 112 is also defined for controlling the energy to the heating element described above. That is, when the print density D = 1 is set, the printing process is stopped when the temperature detected by the temperature sensor 151 reaches the print stop temperature T1 = 50 [° C.], and the temperature sensor is used for subsequent cooling (natural cooling). It is set so that the printing process is resumed when the temperature detected by 151 reaches the restart temperature T2 = 40 [° C.].

  Similarly, when the print density D = 2, the print process is stopped at the print stop temperature T1 = 55 [° C.], and the print process is restarted at the restart temperature T2 = 44 [° C.]. When the print density D = 3, the print process is stopped at the print stop temperature T1 = 60 [° C.], and the print process is restarted at the restart temperature T2 = 48 [° C.]. When the print density D = 4, the print process is stopped at the print stop temperature T1 = 65 [° C.], and the print process is restarted at the restart temperature T2 = 52 [° C.]. When the print density D = 5, the print process is stopped at the print stop temperature T1 = 70 [° C.], and the print process is restarted at the restart temperature T2 = 56 [° C.]. When the print density D = 6, the print process is stopped at the print stop temperature T1 = 75 [° C.], and the print process is restarted at the restart temperature T2 = 60 [° C.]. When the print density D = 7, the print process is stopped at the print stop temperature T1 = 75 [° C.], and the print process is restarted at the restart temperature T2 = 60 [° C.]. When the print density D = 8, the print process is stopped at the print stop temperature T1 = 75 [° C.], and the print process is restarted at the restart temperature T2 = 60 [° C.]. When the print density D = 9, the print process is stopped at the print stop temperature T1 = 75 [° C.], and the print process is restarted at the restart temperature T2 = 60 [° C.]. When the print density D = 10, the print process is stopped at the print stop temperature T1 = 75 [° C.], and the print process is restarted at the restart temperature T2 = 60 [° C.].

  That is, basically, when the print density D set in step S105 is relatively high (that is, the heat sensitive layer of the roll paper S has low sensitivity), the print stop temperature T1 is set relatively high, When the set print density D is relatively low (that is, the heat sensitive layer of the roll paper S has high sensitivity), the print stop temperature T1 is set relatively low. Here, as a feature of the present embodiment, the value of the print stop temperature T1 shown in FIG. 7A is a color development prevention temperature TA [° C.] that is predetermined from the viewpoint of preventing erroneous color development of the heat-sensitive layer (each claim). This is equivalent to the color development limit temperature or transfer limit temperature described in the paragraph (which is set to a value slightly lower than the color development temperature of the actual heat-sensitive layer described above), and is due to the high heat of the thermal line head 112, which is a different viewpoint. It is set by selecting the lower one of the head deterioration prevention temperature TB [° C.] (corresponding to the deterioration limit temperature described in each claim) determined in advance from the viewpoint of preventing durability deterioration (see FIG. 7 (b)).

  That is, in addition to the erroneous color development of the heat-sensitive layer, as another example of inconvenience that may occur when the temperature of the thermal line head 112 becomes excessively high, deterioration of durability of the thermal line head 112 itself due to overheating is assumed. sell. Therefore, in this embodiment, as shown in FIG. 7B, the head deterioration prevention temperature TB (actual thermal line head 112 as an allowable limit that does not cause deterioration in durability according to the specifications of the thermal line head 112. Is set and stored at a value slightly lower than the temperature at which the durability decreases. The head deterioration prevention temperature TB is set to a fixed value regardless of the value of the print density D as shown in the figure, and is set uniformly to TB = 75 [° C.] in this example.

  On the other hand, as shown in FIG. 7B, the coloring prevention temperature TA for preventing erroneous color development of the heat sensitive layer by receiving heat from the thermal line head 112 is relatively higher as the printing density D is relatively higher. Therefore, the lower the print density D, the lower the value. Specifically, when the printing density D = 1, the coloring prevention temperature TA = 50 [° C.], when the printing density D = 2, the coloring prevention temperature TA = 55 [° C.], and when the printing density D = 3, the coloring prevention temperature TA = 60 [° C.]. In the case of the printing density D = 4, the coloring prevention temperature TA = 65 [° C.], in the printing density D = 5, the coloring prevention temperature TA = 70 [° C.], and in the printing density D = 6, the coloring prevention temperature TA = 75 [° C.]. When the printing density D = 7, the coloring prevention temperature TA = 80 [° C.] When the printing density D = 8, the coloring prevention temperature TA = 85 [° C.] When the printing density D = 9, the coloring prevention temperature TA = 90 [° C.] At the density D = 10, the color development preventing temperature TA is 95 [° C.].

  As a result, as shown in FIG. 7B, at the print density D = 1 to 5, the color prevention temperature TA is lower, so this color prevention temperature TA is selected and becomes the print stop temperature T1 (FIG. 7). 7 (a)), at the print density D = 7 to 10, the head deterioration prevention temperature TB is lower, so the color development prevention temperature TB is selected and becomes the print stop temperature T1 (see FIG. 7 (a)). ). Note that, at the print density D = 6, the color development prevention temperature TA and the head deterioration prevention density TB have the same value, so either one is selected and becomes the print stop temperature T1 (see FIG. 7A). At this time, the table shown in FIG. 7B is stored in the EEPROM 235 similarly to the above, and the print stop temperature T1 is set by selectively using the coloring prevention temperature TA and the head deterioration prevention temperature TB as described above. Also good. Alternatively, only the table of FIG. 7A may be used (in this case, the table of FIG. 7B may not be stored).

  The print stop temperature T1, the color development prevention temperature TA, and the head deterioration prevention temperature TB correspond to the limit temperatures described in the claims, and the restart temperature T2 corresponds to the release temperature. In addition, the step S110 functions as a limit temperature setting unit described in each claim and also functions as a release temperature setting unit.

  When the setting of the print stop temperature T1 and the restart temperature T2 is completed as described above, the process proceeds to step S115 in FIG.

  In step S115, the CPU 231 outputs a control signal to the roller drive circuit 244. As a result, the drive motor drives the platen roller 111 and starts transporting the roll paper S.

  In step S120, the CPU 231 outputs a control signal corresponding to the print command already acquired together with the print start instruction at this time to the head drive circuit 243. Thereby, the thermal line head 112 starts printing corresponding to the print command on the roll paper S.

  Thereafter, in step S125, the CPU 231 determines whether or not the tape conveyance has progressed until the thermal line head 112 reaches the conveyance direction position (printing end position) at which all the printing on the roll paper S is completed based on the print command. To do. This determination may be performed by detecting an appropriate identification mark provided on the roll paper S, for example. Alternatively, the transport distance from a certain reference position may be detected by a predetermined known method (such as counting the number of pulses output from the roller drive circuit 244 that drives the drive motor that is a stepping motor). Until the print end position is reached, the determination in step S125 is not satisfied, and the routine goes to step S130.

  In step S130, based on the detection result of the temperature sensor 151, the CPU 231 determines whether the temperature T of the thermal line head 112 has become equal to or higher than the print stop temperature T1 (T ≧ T1). While T <T1, the determination in step S130 is not satisfied (S130: NO), and the process returns to step S125 and the same procedure is repeated. On the other hand, if T ≧ T1, the determination in step S130 is satisfied (S130: YES), and the process proceeds to step S135. In step S135, the CPU 231 outputs a control signal to the head driving circuit 243. As a result, the thermal line head 112 stops printing on the roll paper S. At this time, the CPU 231 stops outputting the control signal to the roller drive circuit 244, for example. Thereby, the rotation of the platen roller 111 is stopped, and the conveyance of the roll paper S is stopped. Thereafter, the process proceeds to step S137. This step S135 functions as a stop control means described in each claim.

  In step S137, the CPU 231 determines whether the temperature T of the thermal line head 112 is equal to or lower than the restart temperature T2 (T ≦ T2) based on the detection result of the temperature sensor 151. While T> T2, the determination in step S137 is not satisfied (S137: NO), and a loop waits. If T ≦ T2, the determination in step S137 is satisfied (S137: YES), and the process returns to step S115 described above. Thereafter, the conveyance of the roll paper S and the printing by the thermal line head 112 are resumed. Steps S115 and S120 when returning in this way function as restart control means described in each claim.

  On the other hand, if the conveyance of the roll paper S has progressed until the thermal line head 112 reaches the print end position in step S125, the determination is satisfied, and the routine goes to step S140.

  In step S140, the CPU 231 outputs a control signal to the head drive circuit 243 as in step S135. Thereby, the thermal line head 112 finishes printing on the roll paper S.

  Thereafter, the process proceeds to step S145, and the CPU 231 determines, for example, the roller drive circuit 244, as in step S135, when the roll paper S reaches a predetermined conveyance direction position (a position to be cut by the fixed teeth 160 by the operator). Stops output of control signal to. Thereby, the rotation of the platen roller 111 is stopped, and the conveyance of the roll paper S is stopped. Thereby, the roll paper S which has been printed as described above and discharged from the discharge port 107 is manually cut by the operator using the fixed teeth 160. Thereafter, this flow is terminated.

  As described above, in the present embodiment, the printing stop temperature T1 at which the printing process is stopped is variable. That is, according to whether the print density D is set to be higher or lower in steps S100 and S105, the print stop temperature T1 is set to be changed between high and low in step S110. Thereby, when roll paper S provided with a high-sensitivity heat-sensitive layer is used, a lower printing stop temperature T1 is used, and the printing process can be reliably stopped at a low temperature. Conversely, when roll paper S having a low-sensitivity heat-sensitive layer is used, it is possible to continue the printing process up to a relatively high temperature without stopping while using a higher printing stop temperature T1. As a result of the above, it is possible to avoid inconvenience due to the excessively high temperature of the thermal line head 112 while sufficiently supporting the high / low sensitivity of the thermal layer and the corresponding high / low setting of the print density D. it can.

  Further, in the present embodiment, in particular, the coloring prevention temperature TA from the viewpoint of preventing the coloring of the heat sensitive layer as described above and the head deterioration preventing temperature TB from the viewpoint of preventing the durability deterioration of the thermal line head 112. The print stop temperature T1 in which both are considered is used. That is, when the temperature of the thermal line head 112 detected by the temperature sensor 151 reaches the lower one of the temperatures TA and TB, the printing process is stopped. Thereby, it is possible to reliably prevent both the erroneous color development of the heat sensitive layer and the deterioration of the durability of the thermal line head 112. At this time, in particular, the coloring prevention temperature TA is set to be relatively high when the set print density D is relatively high, and relatively set when the print density D is relatively low. It is set low (see FIG. 7B). Thereby, it is possible to reliably prevent both the erroneous color development of the heat sensitive layer and the deterioration of the durability of the thermal head in response to the high and low sensitivity of the heat sensitive layer of the roll paper S.

  In the present embodiment, in particular, when the temperature T detected by the temperature sensor 151 reaches the restart temperature T2, the printing process that has been stopped in step S135 is resumed (steps S115 and S120 returned from step S135). ). Thereby, it is possible to quickly return to the printing process while avoiding the disadvantages caused by the high temperature of the thermal line head 112 described above. In the present embodiment, the resuming temperature T2 is also set so as to be changed between high and low so as to be linked to the set print density D (see FIG. 7A). As a result, based on the setting of the print stop temperature T1, which is variable according to the high / low print density D as described above, the print process is performed at a lower temperature when the temperature at which the print process is stopped is relatively low. When the temperature at which the printing process is resumed is relatively high, the printing process is resumed at a higher temperature. As a result, it is possible to smoothly and quickly realize the stop of the printing process and the subsequent restart of the printing process for avoiding inconvenience due to the high temperature of the thermal line head 112.

  In the present embodiment, in particular, the print density D in the printing process is set based on the print density setting instruction from the operator acquired from the external terminal 400 in step S100. Thereby, the print density D according to the manual setting by the operator can be variably set.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and technical idea of the present invention. Hereinafter, such modifications will be described in order.

(1) Case where Roll Paper Attribute is Detected and Automatic Density is Set In the above embodiment, the print density D in the printing process is set based on the manual instruction of the operator at the external terminal 400. However, the present invention is not limited to this. For example, a paper sensor 152 (attribute acquisition means; see the imaginary line in FIG. 5) is provided at an appropriate location of the printer 1. In response to this, the print density D may be automatically set in step S105 of FIG. 6 (in this case, step S100 is omitted).

  In this modification, the print density D can be automatically variably set in accordance with the attribute of the roll paper S without the operator manually setting it.

(2) Expansion to thermal transfer method In the above, the roll paper S provided with a heat-sensitive layer that develops color by receiving heat from the thermal line head 112 has been described as an example of the printing medium, but is not limited thereto. For example, as another example of the printing medium, a printing medium provided with a transfer layer capable of printing by ink thermal transfer from an ink ribbon interposed between the thermal head and the thermal head may be used. In this case, the print medium includes a transfer layer as a print layer formed of a transfer material that can be printed by thermal transfer from the ink ribbon on the surface of the ink ribbon (in other words, the thermal head side). . Also in this case, when the temperature of the thermal head becomes excessively high and reaches a transfer temperature at which the thermal transfer can be performed, there is a possibility that an erroneous transfer of ink may occur regardless of the formation of the desired print. Therefore, the same effect can be obtained by applying the method of the above-described embodiment.

(3) Others The above has described the case where the present invention is applied to the printer 1 driven by a battery power source as a printing apparatus, but is not limited thereto. That is, as an example of a printing apparatus, for example, a printer that forms an image or prints characters on a normal printing paper (printing medium) such as A4, A3, B4, or B5 size with a thermal head, or a printing tape (covered) The present invention may be applied to a print label producing apparatus for producing a print label by performing desired printing on a print medium) with a thermal head. In this case, the same effect is obtained.

  In addition, in the above, the arrow shown in each figure of FIG. 5 etc. shows an example of the flow of a signal, and does not limit the flow direction of a signal.

  In addition, the flowchart shown in FIG. 6 and the like does not limit the present invention to the procedure shown in the above flow, and the procedure is added / deleted or the order is changed without departing from the spirit and technical idea of the invention. Also good.

  In addition to those already described above, the methods according to the above-described embodiments and modifications may be used in appropriate combination.

  In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

1 Printer (printing device)
111 Platen roller (conveying means)
112 Thermal line head (thermal head)
151 Temperature sensor (temperature detection means)
243 Head drive circuit (energization means)
244 Roller drive circuit (drive means)
D Print density S Roll paper (print medium)
T1 Printing stop temperature

Claims (7)

A transport means for transporting a print medium having a print-receiving layer comprising a heat-sensitive layer that develops color by receiving a predetermined amount of heat or a transfer layer that receives heat transfer from an ink ribbon;
Driving means for driving the conveying means;
A thermal head that includes a plurality of heating elements and that performs printing on the printing medium transported by the transporting unit;
Energization means for controlling energization of the plurality of heating elements of the thermal head;
Have
A printing apparatus that executes a printing process for forming a desired print on the printing medium,
Temperature detecting means for detecting the temperature of the thermal head;
When the temperature detected by the temperature detection means rises with the creation of the printed matter and reaches the limit temperature, the drive means and the energization means are controlled in cooperation so as to stop the printing process. Stop control means;
A density setting means for setting the print density in the printing process by variably setting the energy applied by the energizing means to the heating element;
Limit temperature setting means for setting the limit temperature by changing it to high or low according to the print density set by the density setting means,
A printing apparatus comprising: The printing apparatus according to claim 1.
The limit temperature setting means includes
When the printing density set by the density setting means is relatively high, the limit temperature is set relatively high, and when the printing density set by the density setting means is relatively low A printing apparatus, wherein the temperature limit is set relatively low. The printing apparatus according to claim 1.
The stop control means includes
The temperature detected by the temperature detecting means is the limit temperature for preventing deterioration of the durability of the thermal head as the limit temperature, and the color limit temperature for preventing color development or transfer of the printing layer. Alternatively, when the temperature reaches a lower one of the transfer limit temperatures, the driving unit and the energizing unit are controlled in cooperation so as to stop the printing process.
A printing apparatus characterized by that. The printing apparatus according to claim 3.
The limit temperature setting means includes
Regarding the color limit temperature, when the print density set by the density setting unit is relatively high, the limit temperature is set relatively high, and the print density set by the density setting unit is relatively If the temperature is low, the temperature limit is set relatively low. The printing apparatus according to any one of claims 1 to 4,
After the printing process is stopped by the control of the stop control unit, when the temperature detected by the temperature detection unit falls and reaches the release temperature, the driving is performed so that the stopped printing process is resumed. Restart control means for controlling the means and the energization means in cooperation with each other;
A release temperature setting means for setting the release temperature to be changed between high and low according to the print density set by the density setting means;
A printing apparatus comprising: The printing apparatus according to any one of claims 1 to 5,
Density instruction acquisition means for acquiring density instruction information corresponding to a desired print density instruction input by an operator;
The concentration setting means includes:
A printing apparatus that sets the print density in the printing process based on the density instruction information acquired by the density instruction acquisition unit. The printing apparatus according to any one of claims 1 to 5,
Attribute acquisition means for acquiring attribute information of the printing medium;
The concentration setting means includes:
A printing apparatus that sets the print density in the printing process based on the attribute information of the printing medium acquired by the attribute acquisition unit.

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