Printing device and control method of printing device

Abstract

To inhibit sticking from occurring to improve a printing quality.SOLUTION: A control device is provided with: a driving voltage supply part that supplies driving voltages to a printing head; a heating voltage supply part that supplies heating voltages lower than the driving voltages to the printing head; driving voltage supply lines through which the driving voltages are supplied from the driving voltage supply part to the printing head; a connecting part that connects the heating voltage supply lines, through which the heating voltages are supplied from the heating voltage supply part to the printing head, to each other, so as to supply voltages on which the driving voltages and the heating voltages are superimposed to the printing head; and a control part that stops supply of the driving voltages to the driving voltage supply lines by the driving voltage supply part, while continuing the supply of the heating voltages from the heating voltage supply part, on the basis of printing data for driving the printing head, so as to supply heating currents generated by the heating voltages to the printing head.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a printing device and a printing method. [Background technology]

[0002] Conventionally, line printers equipped with thermal heads have been known. Line printers move the thermal paper one line after printing one line. Such printers print by applying heat to the thermal head to color the thermal paper. However, if the temperature of the thermal head drops, the thermal agent on the thermal paper may stick to the thermal head, resulting in smeared prints. This print defect caused by the sticking of the thermal agent is called "sticking." A technology has been disclosed that suppresses this sticking and also suppresses degradation of print quality by varying the applied energy based on print data, temperature, and drive voltage conditions after a predetermined number of lines (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-068289 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technique described in Patent Document 1 has problems such as uneven print density.

[0005] The present invention has been made in view of the above circumstances, and has an object to prevent sticking from occurring and improve print quality. [Means for solving the problem]

[0006] A printing device according to one aspect of the present invention comprises a drive voltage supply unit that supplies a drive voltage to a print head; a heating voltage supply unit that supplies a heating voltage that is lower than the drive voltage to the print head; a connection unit that connects a drive voltage supply line that supplies the drive voltage from the drive voltage supply unit to the print head and a heating voltage supply line that supplies the heating voltage from the heating voltage supply unit to the print head, and supplies a voltage that is a superimposition of the drive voltage and the heating voltage to the print head; and a control unit that supplies a heating current generated by the heating voltage to the print head by continuing to supply the heating voltage from the heating voltage supply unit while stopping the supply of the drive voltage to the drive voltage supply line by the drive voltage supply unit based on print data that drives the print head.

[0007] A printing method according to one aspect of the present invention includes supplying a drive voltage to a print head; supplying a heating voltage to the print head that is lower than the drive voltage; supplying a voltage that is a superposition of the drive voltage and the heating voltage to the print head via a connection that connects a drive voltage supply line that supplies the drive voltage from a drive voltage supply unit to the print head and a heating voltage supply line that supplies the heating voltage from a heating voltage supply unit to the print head; and supplying a heating current due to the heating voltage to the print head based on print data that drives the print head by continuing to supply the heating voltage from the heating voltage supply unit while stopping the supply of the drive voltage to the drive voltage supply line by the drive voltage supply unit. [Effects of the Invention]

[0008] According to the present invention, it is possible to prevent sticking from occurring and improve print quality. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view of a printer device according to an embodiment of the present invention. [Figure 2] FIG. 3 is a diagram illustrating an example of print data according to the present embodiment. [Figure 3]5A and 5B are diagrams illustrating the correspondence between print data and print results according to the present embodiment. [Figure 4] FIG. 2 is a diagram illustrating an example of a functional configuration of a control unit according to the present embodiment. [Figure 5] FIG. 10 is a diagram illustrating an example of print data that is the target of divided driving. [Figure 6] 5A and 5B are diagrams illustrating an example of divided driving of the thermal head according to the present embodiment. [Figure 7] FIG. 2 is a diagram illustrating an example of the configuration of a head driving circuit according to the present embodiment. [Figure 8] 5A and 5B are diagrams illustrating an example of a supply pattern of a driving voltage and a heating voltage according to the present embodiment. [Figure 9] FIG. 10 is a diagram showing a modified example of the configuration of the head drive circuit of the present embodiment. [Figure 10] 10A and 10B are diagrams illustrating modified examples of the supply pattern of the driving voltage and the heating voltage according to the present embodiment. [Figure 11] FIG. 4 is a diagram illustrating an example of the flow of operations of a control unit according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, components having the same or similar functions will be denoted by the same reference numerals. Duplicate descriptions of those components may be omitted.

[0011] 1 is a schematic cross-sectional view of a printer device 1 according to this embodiment. The printer device 1 includes a thermal printer mechanism 10, a control unit 20, a paper storage unit 30, and a paper discharge unit 40. The paper storage unit 30 stores thermal paper 310. In this embodiment, the thermal paper 310 is, for example, roll paper. The thermal paper 310 is coated with a heat-sensitive agent, and when heat equal to or greater than the coloring threshold th1 is applied, the heated portion develops color. The paper discharge unit 40 discharges the paper printed by the thermal printer mechanism 10 (that is, the printed thermal paper 310) to the outside of the printer device 1. The thermal printer mechanism 10 includes a motor 110, a thermal head 120, and a platen roller .

[0012] The motor 110 drives and rotates the platen roller 130 under the control of the control unit 20. The platen roller 130 rotates in conjunction with the rotation of the motor 110 while pressing the color-developing surface of the thermal paper 310 against the thermal head 120, thereby moving the thermal paper 310. As a result, the thermal paper 310 moves relative to the thermal head 120. That is, the motor 110 moves the thermal paper 310 relative to the thermal head 120 via the platen roller 130. In the following description, the movement of the thermal paper 310 by the motor 110 relative to the thermal head 120 is also referred to as paper feeding.

[0013] Here, relative movement refers to the relative movement between the thermal paper 310 and the thermal head 120. That is, relative movement includes a case where the thermal head 120 is fixed and the thermal paper 310 moves, a case where the thermal paper 310 is fixed and the thermal head 120 moves, and a case where both the thermal paper 310 and the thermal head 120 move. In this embodiment, the thermal head 120 is fixed, and the thermal paper 310 moves relative to the thermal head 120.

[0014] The thermal head 120 is a so-called line-type thermal head in which multiple heating elements H are arranged in a line. Based on the control of the control unit 20, the thermal head 120 applies heat to the thermal paper 310 pressed against the platen roller 130, causing the thermal paper 310 to develop color at desired positions.

[0015] The control unit 20 includes a computer device. The control unit 20 controls the motor 110 and the thermal head 120 based on a program stored in a storage unit (not shown) and print data stored in the storage unit (not shown) or print data provided from an external device (not shown). An example of the print data will be described with reference to FIG. 2.

[0016] 2A and 2B are diagrams showing an example of print data according to this embodiment. Fig. 2A shows an example of a character or graphic to be printed (hereinafter simply referred to as the print object). In this example, the print object is the letter "E."

[0017] 1B shows an example of print data. The print data is composed of a matrix of pixels PX and lines LN. In this example, each pixel PX is binary data that represents the print target using two values: black and white. Note that the print data being binary data is just an example. The print data may be multi-value data in which each pixel PX is expressed in multiple gradations between black and white.

[0018] In the example shown in Figure 1B, the print data indicates the letter "E" to be printed. Of the pixels PX indicating the letter "E," the portions that cause the thermal paper 310 to develop a black color are also referred to as black pixels PX-BK. Also, of the pixels PX indicating the letter "E," the portions that do not cause the thermal paper 310 to develop a color are also referred to as white pixels PX-WH. In other words, in binarized print data as in this embodiment, the print object is represented by black pixels PX-BK and white pixels PX-WH. Where necessary in the following description, the coordinates of the print data are indicated by the number of the line LN in the vertical direction in the figure (lines LN1 to LNn; n is a natural number) and the number of the pixel PX in the horizontal direction in the figure (pixel PX1 to pixel PXm; m is a natural number).

[0019] 1C is a diagram showing an example of the configuration of the heating element H portion of the thermal head 120 of this embodiment. The thermal head 120 is made up of multiple heating elements H corresponding to the pixels PX. In the example shown in the figure, the thermal head 120 is equipped with heating elements H1 to Hm corresponding to one line of pixels PX1 to PXm.

[0020] 3A and 3B are diagrams showing the correspondence between print data and print results in this embodiment. (A) in FIG. 3A shows print data similar to the print data shown in (B) in FIG. 2. (B) in FIG. 3B shows an example of the result printed on thermal paper 310 based on the print data. As described above, the thermal head 120 has multiple heating elements H corresponding to the pixels PX of the print data. The thermal head 120 heats the heating elements H that correspond to the black pixels PX-BK among the pixels PX of the print data. The thermal head 120 applies heat equal to or greater than the coloring threshold th1 to the target print positions on the thermal paper 310 that correspond to the black pixels PX-BK by using the heat generated by the heating elements H, thereby causing the thermal paper 310 at the target print positions to color. In the following description, heating the heating element H corresponding to the black pixel PX-BK and causing the thermal paper 310 at the target print position to develop color is also referred to as "printing with the thermal head 120" or simply "printing."

[0021] The thermal head 120 of this embodiment is a so-called line-type thermal head, and performs printing line by line LN. In the example shown in the figure, two lines LN, line LN1 and line LN2, are printed. In the following description, of the multiple lines LN included in the print data, the lines LN printed on the thermal paper 310 are referred to as "printed lines," and the lines LN not yet printed on the thermal paper 310 (but to be printed) are referred to as "unprinted lines." The control unit 20 that controls printing by the thermal head 120 will be described in detail with reference to FIG.

[0022] 4 is a diagram showing an example of the functional configuration of the control unit 20 of this embodiment. The control unit 20 includes a print data acquisition unit 210, a drive plan generation unit 220, a motor drive unit 230, a head drive unit 240, and a heating voltage supply unit 250.

[0023] The print data acquisition unit 210 acquires print data from a storage unit (not shown) or an external device (not shown). As described above, print data is composed of multiple lines LN, and is data that indicates the color development state of each pixel PX included in the line LN. As described above, the print data is composed of a matrix of pixel PX directions and line LN directions. In one example of this embodiment, the print data is binarized data in which each pixel PX expresses the print object using two values, black and white. The print data expresses the print object using black pixels PX-BK and white pixels PX-WH.

[0024] That is, the print data acquisition unit 210 acquires print data that is made up of a plurality of lines LN and indicates the color development state of each pixel PX included in the lines LN.

[0025] The drive plan generation unit 220 generates information on a plan for driving the motor 110 and the thermal head 120 (i.e., a motor drive plan and a head drive plan; hereinafter, these are collectively referred to simply as drive plans) based on the print data acquired by the print data acquisition unit 210. An example of the motor drive plan will be described with reference to FIG. 6.

[0026] The drive plan generator 220 generates a motor drive plan to control the relative movement speed of the thermal paper 310 moved by the motor 110. In other words, the drive plan generator 220 functions as a speed controller that controls the movement speed of the thermal paper 310. The motor driving unit 230 supplies the motor 110 with a driving current for step driving for each line LN based on the motor driving plan generated by the driving plan generating unit 220. The head driving unit 240 supplies the thermal head 120 with a current (that is, a head driving current) that heats the thermal head 120 for each pixel PX.

[0027] As described above, the printer 1 of this embodiment is a so-called line printer. For each line LN of print data, the printer 1 moves the thermal paper 310 by one line, stops the movement of the thermal paper 310, and drives the thermal head 120 to color the thermal paper 310. This operation is repeated to sequentially print multiple lines LN.

[0028] [About split drive of thermal head] Here, we will explain the divided driving of the heating elements H of the thermal head 120. The heating elements H generate heat when a driving current is supplied to them. When multiple heating elements H are driven simultaneously, the total driving current may exceed the power supply capacity of the printer device 1 (or a current limit value based on conditions such as the structure and driving circuit of the thermal head 120; the same applies in the following explanation). In such cases, the driving plan generation unit 220 reduces the number of heating elements H driven simultaneously and the driving current by printing one line LN in a time-divided manner. Printing one line LN in a time-divided manner is also called "time-divided driving" or simply "divided driving."

[0029] 5 is a diagram showing an example of print data that is the target of divided driving. In the example shown in the figure, the kth (k is a natural number) line LN, line Lk, has pixels PX1 to PXm for one line that are all set to black pixels PX-BK. When printing this line Lk, all of the heating elements H1 to Hm corresponding to pixels PX1 to PXm for one line must be heated.

[0030] A large number of black pixels PX-BK per line LN is also referred to as a "high printing rate." In other words, when printing a line LN with a high printing rate, if all of the heating elements H corresponding to the black pixels PX-BK are heated simultaneously, the total drive current may exceed the power capacity of the printer device 1.

[0031] 6 is a diagram showing an example of divided driving of the thermal head 120 of this embodiment. In the example shown in the figure, the thermal head 120 is divided and driven in order from [A] to [D] in the figure. For example, in [A] in the figure, heating elements H1 to H3 are driven. In [B] in the figure, heating elements H4 to H6 are driven. In [C] in the figure, heating elements H7 to H9 are driven. In [D] in the figure, heating elements H(m-2) to Hm are driven. Although the figure shows a case where three adjacent heating elements H are driven simultaneously, this is just an example. The number of heating elements H that are driven simultaneously is determined arbitrarily based on the power capacity of the printer device 1.

[0032] The print data for divided driving includes a block print pattern in which one line is divided into a plurality of blocks and printed.

[0033] Generally, when the thermal head 120 is heated to melt the thermal agent applied to the thermal paper 310 and the temperature of the thermal head 120 drops, the melted thermal agent may solidify and stick to the thermal head 120. When the thermal agent sticks to the thermal head 120, it can cause print quality degradation, such as smeared print. This printing defect caused by the thermal agent sticking to the thermal head 120 is called sticking. When the divided drive described above is performed, the heating element H after driving is finished will be in contact with the thermal paper 310 for a longer period of time than when the divided drive is not performed. In general, when the divided drive is performed, sticking is more likely to occur than when the divided drive is not performed.

[0034] In order to prevent sticking, it is effective to apply heat to the thermal agent from the heating element H of the thermal head 120 so that the thermal agent that has once melted does not resolidify, or so that the thermal agent that has resolidified remelts. Therefore, the printer device 1 of this embodiment includes a head drive circuit 22 for applying a voltage to the heat generating element H of the thermal head 120 to generate heat below the coloring threshold th1 of the heat sensitive agent. In the following description, generating heat equal to or greater than the coloring threshold th1 of the thermal agent is referred to as "driving the head," whereas generating heat less than the coloring threshold th1 of the thermal agent is referred to as "heating the head." A specific example of the head drive circuit 22 will be described with reference to FIG.

[0035] [Head drive circuit] 7 is a diagram showing an example of the configuration of the head drive circuit 22 of this embodiment. The head drive circuit 22 is a circuit that connects the head drive unit 240 and the heating voltage supply unit 250 to the thermal head 120, and supplies voltage to the thermal head 120 from a power source (not shown). The head drive circuit 22 includes a drive voltage supply line C1 that supplies a drive voltage from a power source to the thermal head 120 based on the control of the head drive unit 240, and a heating voltage supply line C2 that supplies a heating voltage to the thermal head 120 based on the control of the heating voltage supply unit 250. The driving voltage supply line C1 and the heating voltage supply line C2 are connected to each other at a connection portion 226.

[0036] On the drive voltage supply line C1 side, the head drive circuit 22 includes a head drive transistor 221 and a pull-up resistor 222. The head drive transistor 221 is, for example, a p-channel field effect transistor. The head drive transistor 221 has a source terminal connected to a power supply and the pull-up resistor 222, a gate terminal connected to the head drive unit 240 and the pull-up resistor 222, and a drain terminal connected to the connection unit 226. The head drive transistor 221 performs an on / off operation under the control of the head drive unit 240, and controls whether or not a drive voltage is supplied to the thermal head 120. When the head drive transistor 221 is turned on, a drive voltage is supplied to the thermal head 120.

[0037] The head driver 240 controls the heating elements H corresponding to the black pixels PX-BK among the heating elements H1-Hm to the ON state by individually driving the control lines (not shown) individually connected to the heating elements H1-Hm of the thermal head 120. When the heating elements H are controlled to the ON state while a driving voltage is being supplied to the thermal head 120, heat equal to or greater than the coloring threshold th1 is applied to the target printing position on the thermal paper 310. As a result, the target printing position on the thermal paper 310 develops color.

[0038] That is, the head driver 240 (drive voltage supply unit) supplies a drive voltage to the thermal head 120 (print head).

[0039] On the heating voltage supply line C2 side, the head drive circuit 22 includes a head warming transistor 223, a pull-up resistor 224, and a current-limiting resistor 225. The head warming transistor 223 is, for example, a p-channel field-effect transistor. The head warming transistor 223 has a source terminal connected to a power supply and the pull-up resistor 224, a gate terminal connected to the heating voltage supply unit 250 and the pull-up resistor 224, and a drain terminal connected to a connection unit 226 via the current-limiting resistor 225. The head heating transistor 223 performs an on / off operation under the control of the heating voltage supply unit 250, and controls whether or not a heating voltage is supplied to the thermal head 120. When the head heating transistor 223 is turned on, a heating voltage is supplied to the thermal head 120.

[0040] The heating voltage supply line C2 has a current limiting resistor 225, which causes a voltage drop, making the heating voltage lower than the voltage of the power supply. If the power supply connected to the head driving transistor 221 (i.e., the power supply for the driving voltage) and the power supply connected to the head heating transistor 223 (i.e., the power supply for the heating voltage) are the same, the heating voltage will be lower than the driving voltage. The heating voltage is a voltage that, when the heating element H generates heat, causes the temperature applied to the thermal paper 310 to be less than the color-developing threshold th1, and is also a voltage that is higher than the temperature at which the thermal agent attempting to adhere to the thermal head 120 melts (or re-melts; the same applies below). That is, the heating voltage is a voltage that makes the temperature of the heating element H equal to or higher than the melting temperature of the heat-sensitive agent and lower than the coloring threshold value th1.

[0041] The head driver 240 controls all of the heating elements H1 to Hm of the thermal head 120 to the ON state by driving control lines (not shown) individually connected to the heating elements H1 to Hm. When the heating element H of the thermal head 120 is controlled to the ON state while a heating voltage is being supplied, the heat applied to the thermal paper 310 is less than the coloring threshold th1. As a result, the thermal paper 310 does not develop color, and the heat-sensitive agent that attempts to adhere to the thermal head 120 melts. This prevents sticking from occurring.

[0042] That is, the heating voltage supply unit 250 supplies a heating voltage lower than the drive voltage to the thermal head 120 (print head).

[0043] FIG. 8 is a diagram showing an example of a supply pattern of the driving voltage and the heating voltage in this embodiment. The period during which one line LN is printed includes a driving period and a heating period. In the example shown in the figure, the period during which the head driving unit 240 turns on the head driving transistor 221 (i.e., the driving period) and the period during which the heating voltage supply unit 250 turns on the head heating transistor 223 (i.e., the heating period) alternate. In other words, in this example, the on state of the head driving transistor 221 and the on state of the head heating transistor 223 are exclusively controlled. The exclusively controlled driving voltage and heating voltage are superimposed at the connection 226 (in this example, either the driving voltage or the heating voltage is supplied to the thermal head 120 at the connection 226).

[0044] That is, the connection section 226 of the head driving circuit 22 connects a driving voltage supply line C1 that supplies a driving voltage from the head driving section 240 (driving voltage supply section) to the thermal head 120 (printing head) and a heating voltage supply line C2 that supplies a heating voltage from the heating voltage supply section 250 to the thermal head 120 (printing head), and supplies a voltage that is a superimposition of the driving voltage and the heating voltage to the thermal head 120 (printing head).

[0045] According to the printer device 1 configured in this manner, when the driving voltage is not supplied to the thermal head 120, the heating voltage is supplied, so that the occurrence of sticking can be prevented.

[0046] The head warming transistor 223 is also connected to a power supply for the drive voltage supplied to the head drive transistor 221. The drive voltage power supply outputs, for example, 24 V. That is, a drive voltage (for example, 24 V) is supplied to the head warming transistor 223. The warming voltage supply unit 250 supplies a voltage (for example, about 3 V) obtained by dropping the drive voltage to the thermal head 120 (print head) as a warming voltage. The heating voltage needs to be lower than the driving voltage, and with the printer device 1 configured as described above, the driving voltage and the heating voltage can be powered from a common power source, simplifying the device configuration.

[0047] The head heating transistor 223 may be connected to the operating power supply of the control unit 20 instead of the power supply for the drive voltage. The operating power supply of the control unit 20 outputs, for example, 3.3 V. In this case, the heating voltage supply unit 250 reduces the voltage supplied from the operating power supply of the control unit 20 (or supplies it as is without reducing it) to the thermal head 120 as the heating voltage. That is, the heating voltage supply unit 250 supplies the voltage of the operating power supply of the control unit 20 as a heating voltage to the thermal head 120 (print head). According to the printer device 1 configured in this manner, the operating power supply for the control unit 20 and the power supply for the heating voltage can be shared, and the device configuration can be simplified.

[0048] Furthermore, in the example described above, when performing divided driving, a heating voltage is supplied to the heating element H of a block where printing has been completed while the heating element H of another block is being driven (i.e., during divided driving), but this is not limited to this. The control unit 20 may be configured to supply a heating current from the heating voltage to the thermal head 120 (print head) after printing the last block of the divided printing by continuing to supply the heating voltage from the heating voltage supply unit 250 while stopping the supply of the driving voltage to the driving voltage supply line C1 by the head driving unit 240 (driving voltage supply unit). According to the printer device 1 configured in this way, power consumption and printing time can be further reduced.

[0049] [Modification of head driving circuit] 9 is a diagram showing a modified configuration of the head drive circuit 22 of this embodiment. Head drive circuit 22A differs from the head drive circuit 22 described above in that it includes a diode 227 at the connection section 226 described above. Note that the same components as those in the head drive circuit 22 are given the same reference numerals and their description will be omitted.

[0050] That is, the connection unit 226 has a diode 227 whose cathode is connected to a driving voltage supply line C1 that supplies a driving voltage from the head driving unit 240 (driving voltage supply unit) to the thermal head 120 (print head), and whose anode is connected to a heating voltage supply line C2 that supplies a heating voltage from the heating voltage supply unit 250 to the thermal head 120 (print head).

[0051] As described above, the driving voltage is higher than the heating voltage. In this modification, the connection part 226 is provided with the diode 227, so that even if the head driving transistor 221 and the head heating transistor 223 are simultaneously turned on, current can be prevented from flowing from the driving voltage supply line C1 to the heating voltage supply line C2.

[0052] 10 shows a modified example of the supply pattern of the drive voltage and the warming voltage of this embodiment. Unlike the supply pattern shown in FIG. 8, the warming voltage is not turned on and off every time one line is printed, and the head warming transistor 223 remains on even during the drive period. As described above, the warming voltage is lower than the driving voltage, so when the driving voltage is being output (when the head driving transistor 221 is in the on state), the warming voltage is not output to the thermal head 120. On the other hand, when the drive voltage is no longer output (the head drive transistor 221 is turned off), the heating voltage is output to the thermal head 120.

[0053] That is, based on the printing data that drives the thermal head 120 (printing head), the control unit 20 continues to supply the heating voltage from the heating voltage supply unit 250 while stopping the supply of the driving voltage to the driving voltage supply line C1 by the head driving unit 240 (driving voltage supply unit), thereby supplying a heating current due to the heating voltage to the thermal head 120 (printing head).

[0054] With the printer device 1 configured in this manner, the on / off control of the heating voltage can be omitted, simplifying the control and eliminating the time required to keep the head heating transistor 223 in the off state until the drive voltage drops below the heating voltage.

[0055] In addition, when using either the head drive circuit 22 or the head drive circuit 22A described above, the dot pattern (energization pattern) of the heating element H to which the heating voltage is applied can be set arbitrarily based on the structure of the thermal head 120.

[0056] For example, a heating current may be applied to all the heating elements H of the thermal head 120. Here, the heating current refers to a current based on a heating voltage. That is, the print data may include a first energization pattern that applies a heating current to all dots included in a predetermined area of ​​the thermal head 120 (print head). According to the printer device 1 configured in this manner, the thermal head 120 can be heated evenly and sufficiently, making it more difficult for sticking to occur.

[0057] For example, the heating voltage may be configured to pass a heating current through some of the heating elements H of the thermal head 120. For example, as long as the current value necessary to heat the thermal head 120 to prevent sticking can be secured, the heating current may be passed through every other heating element H arranged on the thermal head 120 or every n heating elements H (n is a natural number). That is, the print data may include a second energization pattern that applies a heating current to a predetermined percentage of the dots contained in a predetermined area of ​​the thermal head 120 (print head). According to the printer device 1 configured in this manner, the current value for heating the thermal head 120 can be kept low, and power consumption can be reduced.

[0058] [Operation flow of the control unit] 11 is a diagram showing an example of the flow of operations of the control unit 20 of this embodiment. With reference to this diagram, the flow of operations of the control unit 20 when performing the heating control for suppressing sticking described above will be described.

[0059] (Step S110) The print data acquisition unit 210 acquires the print data.

[0060] (Step S120) The drive plan generating unit 220 obtains the number of coloring pixels per line PN for the unprinted lines LN of the print data obtained in step S110.

[0061] (Step S130) The drive plan generating unit 220 determines whether or not sticking suppression is necessary. For example, the drive plan generating unit 220 determines that the number of coloring pixels per line PN exceeds a predetermined judgment value and that sticking suppression is necessary. If the driving plan generating unit 220 determines that sticking suppression is not necessary (step S130; NO), the process proceeds to step S150. If the driving plan generating unit 220 determines that sticking suppression is necessary (step S130; YES), the process proceeds to step S140. Generally, sticking occurs due to various conditions such as the ambient temperature of the printer device 1 (particularly the thermal head 120), the drive voltage of the thermal head 120, and the temperature of the thermal head 120. The drive plan generation unit 220 compares the pre-stored conditions for sticking occurrence with the temperature and voltage conditions during printing to determine whether or not sticking suppression is necessary.

[0062] (Step S140) The drive plan generation unit 220 generates a heating plan for suppressing sticking. For example, the drive plan generation unit 220 generates a heating plan for passing a heating current through all of the heat generating elements H in a group for which printing has been completed in divided driving.

[0063] (Step S150) The drive plan generating unit 220 updates the drive plans for the motor 110 and the thermal head 120 (that is, the motor drive plan and the head drive plan) based on the heating plan generated in step S140.

[0064] (Step S160) The motor driving unit 230 drives the motor 110 for one line based on the motor driving plan updated in step S150. (Step S170) The head driver 240 acquires print data corresponding to the line LN indicated by the motor drive plan updated in step S150 from the print data acquired in step S110. The head driver 240 supplies a drive voltage to the heating element H of the thermal head 120 based on the information on the black pixels PX-BK and white pixels PX-WH indicated in the acquired print data. As a result, a color pattern corresponding to one line of print data is printed on the thermal paper 310. Furthermore, the heating voltage supply unit 250 supplies a heating voltage to the heating elements H of the thermal head 120 based on the drive plan for the thermal head 120 updated in step S150.

[0065] (Step S180) The drive plan generating unit 220 determines whether all of the print data acquired by the print data acquiring unit 210 has been printed. If the drive plan generating unit 220 determines that there is an unprinted line LN among the print data acquired by the print data acquiring unit 210 (step S180; NO), the drive plan generating unit 220 returns the process to step S120 and continues the print processing of the next line LN. If the drive plan generating unit 220 determines that all of the print data acquired by the print data acquiring unit 210 has been printed (step S180; YES), the drive plan generating unit 220 ends the series of print processing.

[0066] As described above, according to the printer device 1 of this embodiment, when a driving voltage is not supplied to the thermal head 120, a heating voltage is supplied, thereby preventing sticking due to a drop in temperature of the thermal head 120.

[0067] All or part of the functions of the control unit 20 of the printer device 1 described above may be recorded as a program on a computer-readable recording medium, and this program may be executed by a computer system. The computer system includes hardware such as an OS and peripheral devices. Examples of computer-readable recording media include portable media such as flexible disks, optical magnetic disks, read-only memory (ROM), and CD-ROMs, storage devices such as hard disks built into computer systems, and volatile memory (Random Access Memory: RAM) provided in servers on networks such as the Internet. Volatile memory is an example of a recording medium that retains a program for a certain period of time.

[0068] Furthermore, the above-described program may be transmitted to another computer system via a transmission medium, for example, a network such as the Internet, or a communication line such as a telephone line.

[0069] The program may be a program that realizes all or part of the above-described functions. Note that the program that realizes part of the above-described functions may be a so-called differential program, which is a program that can realize the above-described functions in combination with a program pre-recorded in the computer system.

[0070] The above describes an embodiment of the present invention with reference to the drawings, but the specific configuration is not limited to the above-described embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present invention. [Explanation of symbols]

[0071] 1...printer device, 10...thermal printer mechanism, 20...control unit, 30...paper storage unit, 40...paper discharge unit, 110...motor, 120...thermal head, 210...print data acquisition unit, 220...motor drive plan generation unit, 230...motor drive unit, 240...head drive unit, 250...heating voltage supply unit

Claims

1. a drive voltage supply unit that supplies a drive voltage to the print head; a heating voltage supply unit that supplies a heating voltage lower than the driving voltage to the print head; a connection section that connects a drive voltage supply line that supplies the drive voltage from the drive voltage supply section to the print head and a heating voltage supply line that supplies the heating voltage from the heating voltage supply section to the print head, and supplies a voltage that is a superposition of the drive voltage and the heating voltage to the print head; a control unit that supplies a heating current generated by the heating voltage to the print head by stopping the supply of the driving voltage to the driving voltage supply line by the driving voltage supply unit while continuing the supply of the heating voltage from the heating voltage supply unit based on print data that drives the print head; and A printing device comprising:

2. The connection unit has a diode having a cathode connected to a drive voltage supply line that supplies the drive voltage from the drive voltage supply unit to the print head and an anode connected to a heating voltage supply line that supplies the heating voltage from the heating voltage supply unit to the print head. The printing device of claim 1 .

3. The print data includes a first energization pattern for applying the heating current to all dots included in a predetermined area of ​​the print head. The printing device of claim 1 .

4. The print data includes a second energization pattern for applying the heating current to a predetermined percentage of the dots included in a predetermined area of ​​the print head. The printing device of claim 1 .

5. the print data includes a block print pattern in which one line is divided into a plurality of blocks and printed; After printing the last block of the divided printing, the control unit continues to supply the heating voltage from the heating voltage supply unit, while stopping the supply of the driving voltage to the driving voltage supply line by the driving voltage supply unit, thereby supplying a heating current due to the heating voltage to the print head. The printing device of claim 1 .

6. The heating voltage supply unit supplies the voltage of the operating power supply of the control unit as the heating voltage to the print head. The printing device of claim 1 .

7. The heating voltage supply unit supplies a voltage obtained by voltage-dropping the driving voltage to the print head as the heating voltage. The printing device of claim 1 .

8. providing a drive voltage to the print head; supplying a warming voltage to the print head that is lower than the driving voltage; supplying a voltage obtained by superimposing the driving voltage and the heating voltage to the print head by a connection unit that connects a driving voltage supply line that supplies the driving voltage from a driving voltage supply unit to the print head and a heating voltage supply line that supplies the heating voltage from a heating voltage supply unit to the print head; supplying a heating current to the print head by the heating voltage by stopping the supply of the driving voltage to the driving voltage supply line by the driving voltage supply unit while continuing the supply of the heating voltage from the heating voltage supply unit based on print data for driving the print head; A printing method comprising:

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