Printer, printer program, and storage medium

Abstract

Clean the thermal head without applying any stress that could potentially damage it. [Solution] A printer that prints on a sheet of paper by heating elements arranged on a thermal head, comprising: print data acquisition means for acquiring print data to be printed on the sheet of paper; pattern acquisition means for acquiring a cleaning print pattern in which a plurality of print settings for cleaning the heating elements by printing on the sheet of paper are defined in the paper feed direction; and print control means for heating the heating elements according to the acquired print data or cleaning print pattern and printing on the sheet of paper, wherein the cleaning print pattern acquired by the pattern acquisition means is defined as a print pattern that prints a dark color at a density that causes the dirt attached to the heating elements to exceed the melting temperature by continuously printing a predetermined length L or less.

Description

[Technical Field]

[0001] The present invention relates to a printer, a printer program, and a storage medium, and more particularly to a printer provided with a thermal head. [Background Art]

[0002] Printers that include a thermal head and perform printing on paper by heat generated from heating elements disposed on the thermal head are widely used. In printers installed in restaurants, contamination from oily fume may accumulate on the thermal head. Contamination from oily fume impedes printing when the thermal head performs printing, resulting in the problem that white voids occur in portions where the contamination adheres. As a cleaning method for a thermal head in such cases, for example, Patent Document 1 describes a method that uses an abrasive-containing cleaning sheet to remove deposits on the thermal head by polishing. [Related Art] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2008-80508 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] However, in the method described in Patent Document 1, the protective film covering the heating elements is worn away by polishing, such that the heating elements directly come into contact with paper during printing, which may damage the heating elements. As another method, since contamination caused by oily fume melts when heat is applied, a method of melting and removing the contamination using heat generated by the heating elements is also conceivable. However, in the method of melting contamination by heat generated from the heating elements, generating heat for a long time may cause electronic components on the thermal head including the heating elements to deteriorate due to heat and become damaged.

[0005] This invention has been made in view of the above-mentioned problems, and aims to provide a method for cleaning a thermal head without applying stress such as the possibility of damage. [Means for solving the problem]

[0006] The present invention provides a printer that prints on a sheet of paper by generating heat from heating elements arranged on a thermal head, A print data acquisition means for acquiring print data to be printed on the paper to be printed, A pattern acquisition means for acquiring a cleaning print pattern in which multiple print settings are defined in the paper feeding direction for cleaning the heating element by printing on the paper to be printed, The system includes a printing control means that generates heat in the heating element according to the acquired print data or cleaning print pattern, and prints on the paper to be printed, The cleaning print pattern acquired by the pattern acquisition means is defined as a print pattern that prints a dark color at a density that causes the dirt adhering to the heating element to exceed its melting temperature by continuously printing a predetermined length L or less. The present invention provides a printer characterized by the following features. [Effects of the Invention]

[0007] According to the present invention, a cleaning print pattern is obtained and printed, which is defined as a print pattern that prints a dark color at a density that causes the dirt adhering to the heating element to exceed its melting temperature by continuously printing a predetermined length L or less. This provides a printer that can easily and inexpensively clean the thermal head without putting a load on the thermal head, and also provides a program to control the printer. [Brief explanation of the drawing]

[0008] [Figure 1] A diagram showing an example of the printer configuration according to the first embodiment. [Figure 2] A diagram showing an example of a thermal head according to the first embodiment. [Figure 3]A diagram showing an example of the electrical configuration of a printer according to the first embodiment. [Figure 4] This figure shows an example of printing using the first cleaning print pattern of the first embodiment. [Figure 5] This figure shows an example of printing using the second cleaning print pattern of the first embodiment. [Figure 6] This figure shows an example of printing using the third cleaning print pattern of the first embodiment. [Figure 7] This figure shows an example of printing using the fourth cleaning print pattern of the first embodiment. [Figure 8] This figure shows an example of printing using the fifth cleaning print pattern of the first embodiment. [Figure 9] Figure 5(a) shows a modified version of the cleaning print pattern. [Figure 10] This figure shows an example of printing using the cleaning print pattern of the second embodiment. [Figure 11] A diagram showing an example of printing a cleaning print pattern in the second embodiment. [Modes for carrying out the invention]

[0009] Hereinafter, preferred embodiments and modified examples of the printer 1 of the present invention will be described in detail with reference to the drawings. The embodiments of the present invention include, but are not limited to, those shown in the figures. In the following descriptions of each figure, parts that are common to parts already described are denoted by the same reference numerals, and some redundant explanations are omitted.

[0010] Details of the embodiment <About the printer configuration> Figure 1 shows an example of the configuration of printer 1 according to the first embodiment of the present invention. Printer 1 comprises a printer mechanism 10, a paper storage unit 20, and a paper output unit 30. The printer mechanism 10 includes a transport unit 101, a thermal head 102, and a cutting unit 103. The conveyance unit 101 is a mechanism that conveys the printing paper 201 toward the paper discharge unit 30 in synchronization with printing performed by the thermal head 102. The conveyance unit 101 rotates two upper and lower rollers in contact with each other in the same direction, thereby conveying the printing paper 201 sandwiched between the two rollers to the downstream side thereof (toward the thermal head 102 and the paper discharge unit 30). The thermal head 102 is a printing functional unit that performs printing by causing a plurality of heating elements to generate heat and heating the conveyed printing paper 201, and details thereof will be described later.

[0011] The cutting unit 103 cuts the printing paper 201 after printing. The cutting method may be either a partial cut, in which cutting leaves a small uncut portion, or a full cut, in which the paper is completely cut off. Although the cutting unit 103 of the present embodiment performs partial cutting, it can also be configured to perform full cutting. Furthermore, it can also be configured such that either partial cutting or full cutting can be selected by switching between the two.

[0012] The paper storage unit 20 stores the printing paper 201. In the present embodiment, the printing paper 201 is wound into a roll, and for example, thermal paper having a thermosensitive layer formed on one surface is used. Printing is performed on the thermal paper by conveying it while the thermosensitive layer is heated by the thermal head 102. The thermosensitive layer develops color deeper as the applied temperature is higher, and develops color lighter as the applied temperature is lower. In the present embodiment, the printing paper 201 having a thermosensitive layer that develops black color is used, but printing paper 201 that develops other colors, such as dark blue or sepia, can also be used. The paper discharge unit 30 is an opening provided in the housing of the printer 1, and the printing paper 201 printed by the printer mechanism 10 is discharged outward of the printer 1 from the paper discharge unit 30.

[0013] Next, the configuration of the thermal head 102 will be described. FIG. 2 is a diagram showing an example of the thermal head 102 according to the present embodiment. As shown in Figure 2, the thermal head 102 is equipped with a heating element 1021. The heating element 1021 consists of N heating elements 1021n (n=1, 2, ...N: N is a natural number). Here, the number of N is, for example, 512. The N heating elements 1021 are arranged in a line on the thermal head 102 in a direction perpendicular to the paper feeding direction indicated by the arrow. Multiple heating elements 1021 are connected to a single driver IC 1022 and electrically controlled. In Figure 2, six heating elements 1021 are connected to one driver IC 1022, but in reality, tens to hundreds of heating elements 1021 may be connected to a single driver IC 1022. The number of heating elements 1021 connected to a single driver IC varies depending on the number of bits in the driver IC 1022; for example, a 64-bit driver IC 1022 can be connected to a maximum of 64 heating elements 1021.

[0014] The heating element 1021 generates heat when a voltage is applied by the drive IC 1022. The temperature of the heating element 1021 changes depending on the applied voltage. In other words, the lower the voltage applied to the heating element 1021, the lower the temperature of the heating element 1021, and the lighter the color of the paper to be printed on 201. Conversely, the higher the voltage applied to the heating element 1021, the higher the temperature of the heating element 1021, and the darker the color of the paper to be printed on 201. Furthermore, when the thermal head 102 prints on the paper 201, the heating element 1021 comes into contact with the paper 201. For this reason, the heating element 1021 is covered with a protective film (not shown) to prevent wear due to friction with the paper 201 during printing.

[0015] Figure 3 shows an example of the electrical configuration of printer 1 according to an embodiment of the present invention. The printer 1 according to an embodiment of the present invention comprises a control unit 40, a storage unit 50, a display unit 60, an input unit 70, a communication unit 80, and a printer mechanism 10 as described in Figure 1. The transport unit 101, thermal head 102 (drive IC 1022), and cutting unit 103, which constitute the printer mechanism 10, are each connected via interfaces (not shown) for input and output of control data.

[0016] The control unit 40 is comprised of a computer system equipped with a CPU, ROM, and RAM (not shown). The control unit 40 functions as part or all of the print data acquisition means, cleaning print pattern acquisition means, and print control means for printing print data and cleaning print patterns onto the paper to be printed 201, by having the CPU, which is the central processing unit, execute the normal printing program and thermal head cleaning program stored in the memory unit 50. Various programs such as the thermal head cleaning program may be distributed to the printer 1 via a communication line, and the control unit 40 of the printer 1 that receives this distribution may execute the program.

[0017] ROM is read-only memory that stores the basic programs and parameters necessary for the CPU to operate. RAM is a read / write memory such as SRAM or SDRAM, which functions as working memory when the CPU performs various processes such as printing. In the printing process in this embodiment, various data such as print data to be printed and cleaning print patterns are temporarily stored. In this embodiment, the print data and cleaning print patterns temporarily stored in RAM are read from the storage unit 50, which will be described later. As a modification, it is also possible to target data that is input from the input unit 70, further acquired from an external source via the communication unit 80, and further read from a storage medium such as an SD card or USB memory.

[0018] The memory unit 50 consists of a read / write storage medium and a drive device for reading and writing various types of information, such as programs and data, to the storage medium. The storage medium used as this memory unit 50 is a semiconductor storage device such as eMMC (embedded Multi Media Card), but it is also possible to use other semiconductor memory such as magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and SSDs (Solid State Drives). The memory unit 50 stores various programs, such as a normal printing program and a thermal head cleaning program, as well as various data, such as standard printing data used for normal printing (store name, telephone number, etc.) and cleaning printing patterns used for thermal head cleaning. The various programs stored in the memory unit 50 may implement some of the functions of a normal printing program or a thermal head cleaning program. Furthermore, the normal printing program, etc., may be a so-called differential file (differential program) whose functions can be implemented in combination with a program already stored in the control unit 40. The cleaning print patterns stored in the memory unit 50 will be described later.

[0019] The display unit 60 is a display device that displays various menu screens, input data, and print data, and in this embodiment, a liquid crystal display device is used. The menu screen displays a cleaning print button for performing the cleaning print in this embodiment. The input unit 70 consists of a touch panel and a numeric keypad, and accepts selections from menus displayed on the display unit 60 and input operations for the printer 1. The input unit 70 accepts, for example, an input operation (selection of the cleaning print button) to print the cleaning print pattern in this embodiment to clean the thermal head 102. The control unit 40 controls the operation of the printer 1 according to the various operations input from the input unit 70. The communication unit 80 communicates with an external device (not shown) and functions as part of the print data acquisition means by acquiring print data transmitted from the external device. The external device is, for example, a host terminal acting as a management device. Communication between the communication unit 80 and the external device may be conducted via wired or wireless connection. The print data received by the communication unit 80 is temporarily stored in RAM by the control unit 40, and then printed onto the paper to be printed 201 by controlling the printer mechanism 10 according to the normal printing program.

[0020] <How to clean the thermal head> Next, a method for cleaning the thermal head 102 of the printer 1 in this embodiment will be described. In this embodiment, the control unit 40 executes a thermal head cleaning program and prints a cleaning print pattern onto the paper to be printed 201, thereby cleaning the thermal head 102. The thermal head cleaning program is executed when the user detects printing defects such as blank spaces during normal printing by printer 1, or when the user selects the cleaning print button displayed on the menu screen of the display unit 60 from the input unit 70 before printing defects occur. In addition, if periodic cleaning is selected and set from the menu screen, the thermal head cleaning program is automatically executed at predetermined intervals.

[0021] When the thermal head cleaning program is executed, the control unit 40 reads the cleaning print pattern stored in the memory unit 50 and temporarily stores it in RAM. Based on this cleaning print pattern, the drive IC 1022 applies a voltage to each heating element 1021, causing the heating elements 1021 to generate heat. The heat generated by the heating element 1021 warms up the dirt adhering to the thermal head 102. The dirt melts due to the heat generated by the voltage applied when printing at a predetermined density or higher (hereinafter referred to as dark color printing). When a cleaning print pattern is printed on the paper to be printed 201, the paper to be printed 201 is transported by the transport unit 101, which wipes away the melted dirt and cleans the thermal head 102. Here, the predetermined concentration at which the dirt dissolves refers to a print density of 95% or higher and 100% or lower, where, for example, a non-printed state (no application state) where no printing is performed on the paper to be printed on 201 is defined as a print density of 0%, and printing at the highest density is defined as a print density of 100%.

[0022] The heating element 1021 generates heat when a voltage is applied, and if a high voltage is applied continuously for a long period of time, it is highly likely to be damaged by heat. Furthermore, the conductor connecting the heating element 1021 and the drive IC 1022 is also highly likely to be damaged by heat. A high voltage refers, for example, to the voltage used for printing at 100% density. Hereafter, "high voltage" will refer to this voltage. In this way, a state in which the heating element 1021 or the conductor may be damaged due to the application of a high voltage for a long period of time is sometimes referred to as a state in which the thermal head 102 is under load. The possibility of damage to the heating element 1021 and other components increases the longer the high voltage is applied to the heating element 1021, and decreases the shorter the time.

[0023] Thus, when cleaning the thermal head 102 by melting the dirt attached to it, it is necessary to heat the heating element 1021 to a high temperature before printing. However, if the heating element 1021 is heated to a high temperature and printed continuously for a long period of time, the heating element 1021 and other components are likely to be damaged. The inventors have determined a range of continuous printing time using dark ink that allows for the melting of attached dirt while avoiding damage to the heating element 1021 and other components due to thermal load. This continuous printing time can be expressed as another physical quantity, the length of continuous printing L (hereinafter referred to as the cleaning printing length L), that is, a length greater than or equal to the length required for the melting of the dirt, and not exceeding the length at which damage to the heating element 1021 may occur. For example, the cleaning printing length L is within the range of 20 mm ≤ L ≤ 100 mm.

[0024] However, the 20 mm required for the dissolution of the dirt is the print length when the temperature of the dirt reaches the same temperature as the heating element 1021 during dark-color printing. Therefore, if we add the printing length of 30 mm, which is the time it takes for the temperature of the dirt to reach the same temperature as the heating element 1021 during dark-color printing, that is, the printing length L required for the dirt to melt becomes 50 mm from the start of printing. In the printer 1 of this embodiment, a cleaning print length L of L = 50 mm is adopted.

[0025] In the printer 1 of this embodiment, in order to reduce the load on the heating element 1021, the dirt is preheated by printing with a voltage lower than the voltage for dark color printing for the first 30 mm from the start of printing (hereinafter referred to as preheating printing), and the last 20 mm is used for melting the dirt with dark color printing. In this embodiment, preheat printing refers to printing at a density of 60% or more and less than 95%. However, it is also possible to clean the thermal head 102 by printing a dark color over the entire cleaning print length L.

[0026] Alternatively, the heating element 1021 may be divided into multiple groups, and the dark-colored printing locations for each group may be staggered. In this way, by staggering the timing of the dark-colored printing so that not all heating elements 1021 perform dark-colored printing at the same time, it is possible to prevent the overall temperature of the thermal head 102 from rising. In this case, the group of heating elements 1021 may be based on the connection unit to the drive IC 1022, or it may be divided into any number of elements. For example, in Figure 2, six heating elements 1021 are connected to one drive IC 1022, but one group may consist of three heating elements 1021. Also, the number of heating elements 1021 belonging to each group does not have to be equal. It is also possible to print dark ink on all heating elements 1021 simultaneously (or after preheating) without dividing the heating elements 1021 into multiple groups. In this case, in order to suppress damage to the entire thermal head 102, the cleaning print length L should be 20 mm or more, 50 mm or less, preferably 30 mm.

[0027] In the printer 1 of this embodiment, by printing the cleaning print pattern stored in the memory unit 50, all heating elements 1021 are subjected to dark printing of a cleaning print length L, or preheating printing followed by dark printing, at any position along the longitudinal direction of the paper to be printed on 201, thereby cleaning the thermal head 102. Furthermore, while the cleaning print pattern is being printed, the user may be shown, for example, by displaying a string such as "Cleaning in progress" on the display unit 60, to indicate that the printing is not due to a malfunction of the printer 1.

[0028] <About the cleaning print pattern> Next, various cleaning printing patterns in this embodiment will be described using Figures 4 to 9. Of the cleaning print patterns described below, one will be stored in the storage unit 50, but multiple cleaning print patterns may be stored. When saving multiple cleaning print patterns, it is possible to save them separately as a default pattern and a backup pattern. Furthermore, when cleaning the thermal head 102, the control unit 40 can change the order of printing each time cleaning is performed using multiple cleaning print patterns.

[0029] Figure 4 shows the printing status using the first cleaning printing pattern. This first cleaning print pattern is a pattern that performs preheating print and dark-color print with the cleaning print length L for all heating elements 1021 being the same position in the longitudinal direction of the paper to be printed on 201. As shown in Figure 4, the first cleaning printing pattern is a printing pattern in which the printing density is gradually increased by preheating printing. In this printing pattern, a continuous gradient-like printing is performed. The arrows in Figure 4 indicate the paper feeding direction. As the paper to be printed, 201, flows from left to right, printing proceeds from left to right. The range La to Le shown in the diagram represents the cleaning print length L (=50mm), with La to Le each representing a length of 10mm. The first cleaning printing pattern shown in Figures 4(a) and (b) performs preheat printing of La at 70% printing density, Lb at 80% printing density, and Lc at 90% printing density within the cleaning printing length L, followed by dark color printing of Ld and Le at 100% printing density, thereby creating a continuous gradient-like printing.

[0030] As mentioned above, in order to melt the dirt adhering to the thermal head 102, heat needs to be transferred to the dirt. Since the dirt heats up gradually, it does not immediately reach the same temperature as the heating element 1021 when voltage is applied to it. Therefore, in the first cleaning printing pattern, preheating is performed by gradually increasing the voltage applied to the heating element 1021 through preheating printing from La to Lc, in accordance with the time it takes for heat to be transferred to the dirt. This shortens the time during which the heating element 1021 is driven at a voltage that prints with a density of 95% or more (the time for dark color printing), thereby reducing the load on the thermal head 102. The printing on the paper 201 becomes darker as the voltage applied to the heating element 1021 increases. Therefore, in this case, a gradient print from light to dark is produced. The voltage used for preheating and printing should be any voltage that allows printing at a print density of 60% or more and less than 95%, preferably a voltage that allows printing at a print density of 70% or more and less than 95%. In the first cleaning print pattern, the printing before and after the cleaning print length L may be non-printed (printed at 0% density) as shown in Figure 4(a), or it may be printed at a density greater than 0% but less than 60% (hereinafter referred to as light-colored printing) as shown in Figure 4(b).

[0031] Although the first embodiment has been described above, as a variation of the first cleaning print pattern, it is also possible to set the print density in the preheating print range La to Lc, and the print density in the dark color print range Ld and Le to different densities. For example, preheat printing can be started at the minimum value, and then the density values ​​can be appropriately selected within the preheat printing range (60% or more, less than 95%), such as La at 60% density, Lb at 75% density, and Lc at 90% density. Furthermore, for dark-colored printing, the ranges Ld and Le may be set to a density of 95%, or range Ld may be set to a density of 95% and range Le to a density of 100%, allowing for appropriate selection of density values ​​within the dark-colored printing range (density of 95% or more and 100% or less). Furthermore, although preheat printing is defined as being performed in three ranges from La to Lc, it is also possible to perform preheat printing in two parts, La2 and Lb2. In this case, for example, the first La2 would be preheated and printed at a density of 70%, and the next Lb2 at a density of 85%. Furthermore, in this embodiment, the ranges Ld and Le were targeted for dark printing, but dark printing may be performed starting from an earlier point. For example, the ranges La and Lb may be preheated and printed, while Lc to Le may be dark printed. Furthermore, the above variations regarding preheat printing are the same for other cleaning printing patterns described later.

[0032] Next, the second cleaning print pattern will be explained with reference to Figure 5. In this second cleaning printing pattern, the heating elements 1021 are classified into N groups, and the cleaning printing length L for each group is positioned so as not to overlap with the cleaning printing length L of the adjacent group. The pattern is such that the heating elements 1021 of each group are printed in a dark color over the entire cleaning printing length L. Figure 5 shows an example of a second cleaning print pattern. In the second cleaning print pattern, when a certain group performs dark-colored printing with a cleaning print length L, the groups adjacent to that group perform light-colored printing or no printing at all. By having groups adjacent to groups performing non-printing or light-colored printing, the areas where the temperature of the thermal head 102 rises are dispersed, thereby reducing the load on the thermal head 102.

[0033] Here, as shown in Figure 5, the heating element 1021 is divided into six groups g1 to g6, and the positions of the cleaning print length L are designated as L1 to L3 in the length direction of the paper to be printed on 201 (the same applies hereafter). In the second cleaning print pattern, the first cleaning print length L1 is used for dark printing of groups g1 and g4, the next cleaning print length L2 is used for dark printing of groups g2 and g5, and the final cleaning print length L3 is used for dark printing of groups g3 and g6. In the second cleaning marking pattern shown in Figures 5(a) to 5(c), dark markings are printed in two diagonal, stepped rows. Specifically, the first row consists of stepped markings using dark markings (g1, L1), (g2, L2), and (g3, L3), and the second row consists of stepped markings using dark markings (g4, L1), (g5, L2), and (g6, L3). The cleaning print pattern in Figure 5(d) is a pattern where the dark print is not in a stepped shape with two rows.

[0034] Figures 5(a) and (d) show the case where all areas that are not printed in dark color are not printed, (b) shows the case where all areas other than the dark-colored printed areas are printed in light color of the same density, and (c) shows the case where the light color printing on one side of the dark-colored area is of different densities to the other side. The area surrounding the dark-colored print may be left blank, as shown in Figure 5(a), or light-colored print may be applied, as shown in Figure 5(b). When light-colored print is applied around the dark-colored print, multiple shades of light-colored print may be applied, as shown in Figure 5(c).

[0035] In the second cleaning print pattern illustrated in Figure 5, the case where the heating element 1021 is classified into N=6 groups is explained, but it may be classified into any number of groups. The number of classifications is the same for the third to fifth cleaning print patterns described later. Furthermore, although we have described the case where dark printing is performed at three locations with cleaning print lengths L1 to L3 in the longitudinal direction, it is also possible to have odd-numbered groups g1, g3, ... perform dark printing at cleaning print length L1, and even-numbered groups g2, g4, ... perform dark printing at cleaning print length L2. This makes it possible to shorten the overall print length of the second cleaning print pattern. Furthermore, while the second cleaning print pattern illustrated in Figure 5 describes the case where all groups print in dark color across the entire cleaning print length L, as explained in the first cleaning print pattern and its modified examples, it is also possible to preheat and print La to Lc and print in dark color across L within each cleaning print length L.

[0036] Next, the third cleaning print pattern will be explained with reference to Figure 6. In this third cleaning print pattern, the heating elements 1021 are classified into groups g1 to g6, and along the length of the printed paper 201, only one of the groups is printed in a dark color for a cleaning print length L. Figure 6 shows an example of a third cleaning print pattern. The third cleaning print pattern prevents the overall temperature of the thermal head 102 from rising and reduces the load because it prints one group at a time in dark ink, rather than multiple groups printing dark ink simultaneously.

[0037] The cleaning print patterns shown in Figures 6(a) and 6(b) have a single, diagonally arranged, staircase-like row of areas where dark-colored printing is performed (hereinafter referred to as the dark-colored printing area). For cleaning the thermal head 102, all groups only need to print a dark color at any one of the cleaning print lengths L1 to L6, and as shown in Figure 6(c), the dark color printing area does not need to be formed in a diagonal, stepped line.

[0038] Furthermore, the printing around the dark-colored printing may be left blank, as shown in Figure 6(a), or light-colored printing may be performed, as shown in Figure 6(b). When printing light-colored text around dark-colored text, it is acceptable to use multiple shades of light-colored text.

[0039] Next, the fourth cleaning print pattern will be explained with reference to Figure 7. In this fourth cleaning printing pattern, multiple groups do not print in dark color simultaneously, but rather one group at a time. Furthermore, immediately after one group prints in dark color, the groups adjacent to that group do not print in dark color. This fourth cleaning print pattern prevents the overall temperature of the thermal head 102 from rising, and also reduces the load on the thermal head 102 by providing cooling time for the areas to which groups adjacent to the group whose temperature has risen due to dark-color printing belong.

[0040] Figure 7 shows an example of the fourth cleaning print pattern. As shown in Figure 7, the areas surrounding the dark-colored print—front, back, left, right, and diagonally—are either unprinted (a) or lightly printed (b). The area surrounding the dark-colored print may be left blank, as shown in Figure 7(a), or light-colored print may be applied, as shown in Figure 7(b). When light-colored print is applied around the dark-colored print, multiple densities of print may be used.

[0041] Next, the fifth cleaning print pattern will be explained with reference to Figure 8. The fifth cleaning printing pattern is a printing pattern in which, in each of the six groups g1 to g6 of the heating element 1021, a preheating printing region (hereinafter referred to as the preheating printing region) and a dark-colored printing region are formed in a gradient. By gradually increasing the voltage applied to the heating element 1021 and performing preheat printing in accordance with the time it takes for heat to be transferred to the dirt, the time during which the heating element 1021 is driven at the voltage required for dark-color printing is shortened, thereby reducing the load on the thermal head 102. In the fifth cleaning printing pattern shown in Figure 8, (a) and (b) the preheating printing area is formed in a comb-like manner with a gradient by each group, while (c) and (d) the preheating printing area is formed in a staircase-like manner with a gradient by each group, arranged diagonally in a single row.

[0042] In this way, in the fifth cleaning print pattern, the positions of the cleaning print lengths L (L1 to L6) are shifted longitudinally so that the dark-colored print portions of the group do not appear adjacent to each other. This prevents the temperature of the thermal head 102 from rising and reduces the load on the thermal head 102. Regarding the preheating printing area, as shown in Figures 8(a) to (d), the printing areas may be adjacent to each other or they may not be adjacent.

[0043] The gradation produced by the cleaning print patterns shown in Figures 8(a), (b), (c), and (d) is the same as that of the first cleaning print pattern, and is a print pattern consisting of preheat printing with a print density of 70% and a print length of 10 mm, a print density of 80% and a print length of 10 mm, and a dark print with a print density of 100% and a print length of 20 mm. For areas other than the cleaning print length L where gradient printing is performed, printing may be omitted as shown in Figures 8(a) and (c), or light-colored printing may be performed as shown in Figures 8(b) and (d). When light-colored printing is performed around dark-colored printing, printing may be performed at multiple densities.

[0044] Next, the sixth cleaning print pattern will be explained with reference to Figure 9. The sixth cleaning print pattern shown in Figure 9 is a modified version of the second cleaning print pattern shown in Figure 5(a). In the sixth cleaning printing pattern shown in Figure 9, similar to the cleaning printing pattern shown in Figure 5(a), the heating element 1021 is divided into six groups and printed in dark color, so that the dark color printing area is formed in two diagonal, stepped rows. This sixth cleaning print pattern differs from Figure 5(a) in that the fifth group from the bottom, g5, performs a non-printing or light-printing section of length α in the middle of the dark-printing, and then resumes dark-printing. It also differs in that there is a break of length α between the dark-printing of the first group from the bottom, g1, and the dark-printing of the second group from the bottom, g2, and they are not continuous. In this way, by performing non-printing or light-colored printing of length α during or before / after dark-colored printing, the lengths of groups g2 and g5 become cleaning print length L + α, which is α longer than the cleaning print lengths L1 and L3 of the other groups.

[0045] Thus, instead of continuously driving the thermal head 102 at a voltage suitable for dark printing, a voltage lower than the voltage required for dark printing may be applied midway through to print no-print or light-colored print, thereby lowering the temperature of the thermal head 102. When multiple groups perform dark printing simultaneously at the same position along the longitudinal direction of the paper to be printed on 201, the start or end times of the dark printing for each group may be staggered. Furthermore, if one group performs dark-color printing and then another group performs dark-color printing, the end of dark-color printing for the first group and the start of dark-color printing for the other group do not have to be consecutive. Also, the print length of the dark-color printing does not have to be the same for all groups. Such modifications can be applied not only to the second cleaning print pattern shown in Figure 5, but also to other cleaning print patterns and their variations.

[0046] <Regarding printing for checking for printing defects> Next, a second embodiment of printer 1 will be described in detail with reference to Figures 10 and 11. In the first embodiment of the printer 1, the user discovers a printing defect (such as a blank space) in the normally printed area of ​​the print data, and by operating the cleaning print button, the thermal head 102 is cleaned by printing a cleaning print pattern. In contrast, the printer 1 of the second embodiment makes it easier to detect printing defects by printing a printing defect confirmation line 203 on the paper to be printed on 201. Specifically, all heating elements 1021 are heated to print a print defect confirmation line 203 on the paper to be printed 201. If there is dirt on the thermal head 102, the areas where the dirt is present will experience print defects such as white spots or smudges. Therefore, by printing the print defect confirmation line 203 with all heating elements 1021 heated, it is possible to check whether or not there is dirt on the thermal head 102.

[0047] Figure 10 shows an example of the second embodiment. In Figure 10, as an example, a receipt 202 for a restaurant "Ristorante ●●" printed on a printable paper 201 is shown. As shown in Figure 10, the receipt 202 has standard printable data 202a, such as the store name and telephone number, printed at the top, followed by (downstream) food and beverage data (printable data) 202b, such as the date and time, food and beverages, and prices. Further downstream from the food and beverage data 202b, a line 203 for checking printing defects due to heat generation from all heating elements 1021 is printed. Considering the load on the thermal head 102, the density of the print defect detection line 203 is preferably less than 95%. Visibility must also be considered. Therefore, the print density of the print defect detection line 203 is appropriately selected, for example, between 30% and 60%. In the receipt 202 shown in Figure 10, the print defect detection line 203 is printed at a density of 50%. Furthermore, the print width (length in the paper feeding direction) of the print defect confirmation line 203 is a predetermined width β (for example, β = 5 mm, 8 mm, 10 mm, etc.). In this way, by printing the print defect detection line 203 lightly, defects such as white spots occur earlier than in the normally printed areas at 100% density. This allows the thermal head 102 to be cleaned before print defects occur in the normally printed areas.

[0048] In the second embodiment, the heating element 1021 is divided into multiple groups, a number is assigned to each group, and the group number 204 and the group dividing line 205 are printed before or after the print defect confirmation line 203. In the example shown in Figure 10, the heating element 1021 is divided into six groups, and each group is assigned a number from 1 to 6. Before printing for checking for printing defects, the group number is printed. Note that the numbers to be printed are not limited to numbers, as long as they correspond to each group; letters or other symbols may also be used.

[0049] If a user of printer 1 performs a printout for printout confirmation using the printout defect confirmation line 203 and finds printout defects in a specific group, they can specify the group requiring cleaning via the input unit 70 and have the control unit 40 print a cleaning printout pattern for the heating element 1021 corresponding to that group for cleaning. In the case of receipt 202 illustrated in Figure 10, a white gap 206 is observed in group 4. In such cases, the user of printer 1 designates group 4 as the group that needs cleaning. In the second embodiment, the menu screen of the display unit 60 displays not only the cleaning print button but also group selection buttons corresponding to each group of heating elements 1021. The user of the printer 1 selects the group selection button corresponding to the group in which the white area has been identified, and then selects the cleaning print button. Multiple groups can be specified to correspond to the areas with white areas. If the area with a white area is on or near the group divider line 205, the user selects the group selection buttons corresponding to the groups on both sides of the group divider line 205. The cleaning print button and group designation button are selected by operating the input unit 70. However, selection is not limited to the menu screen; selection may also be made from other screens, or a dedicated selection button (hard button) that functions as part of the input unit 70 may be provided, allowing selection to be made using this dedicated selection button.

[0050] The data for printing the print defect confirmation line 203, group number 204, and group divider line 205, which are printed in the second embodiment, is stored in the storage unit 50. It can be stored as part of the standard print data 202a or separately.

[0051] Figure 11 shows an example of printing a cleaning print pattern in a second embodiment of the present invention. Figure 11 shows the cleaning print pattern when the group selection button corresponding to group 4, where white areas occurred in Figure 10, is selected. As cleaning marking patterns, the markings shown in Figure 11(a) are dark-colored markings, while the markings shown in Figure 11(b) are gradient markings created by preheat markings and dark-colored markings. In both Figures 11(a) and 11(b), the cleaning print length L, dark color printing, preheating print, and dark color printing are the same as the cleaning print patterns described in the first embodiment and its modified versions. As with the first embodiment, it is also possible to perform light color printing before or after dark color printing, or before preheating print. Furthermore, if the groups corresponding to multiple selected group buttons are adjacent, the longitudinal position of the target cleaning print length L may be shifted. For example, for dark-colored printing, the position of the cleaning print length L may be shifted in the same way as the second cleaning print pattern in Figure 5, and for gradient printing, the position may be shifted in the same way as the fifth cleaning print pattern in Figure 8.

[0052] According to the second embodiment, printing a printing defect confirmation line 203 makes it possible to more reliably confirm printing defects such as white areas. Furthermore, by reducing the print density of the print defect detection line 203, white spots will occur earlier than in the normally printed areas, making it possible to predict white spots in the normally printed areas in advance. By writing group number 204 before or after the print defect confirmation line 203, it is possible to check for white areas and specify the group. By printing a cleaning print pattern for the areas that need cleaning, the load on the thermal head 102 can be reduced.

[0053] In the second embodiment described, it is also possible to print only the print defect confirmation line 203 and not print the group separator line 205 and the group number 204. In this case, only the Clean Print button is displayed on the menu screen, and the Group Selection button is not required. When the Clean Print button is selected, the control unit 40 cleans the thermal head 102 by printing one of the cleaning print patterns described in the first embodiment.

[0054] In the second embodiment, the case in which the print defect confirmation line 203 is printed after (downstream of) normal printing was described, but it is also possible to print it before (upstream of) normal printing, or to print the print defect confirmation line 203 separately from normal printing. Furthermore, while Figure 10 describes the case where the receipt 202 shown is output from the paper output unit 30 with the normal printing portion (standard printing data 202a, food and drink data 202b) and the printing portion for checking for printing defects (printing defect check line 203, group number 204, group separator line 205) printed consecutively, the normal printing portion and the printing portion for checking for printing defects can be separated by partially cutting between them.

[0055] In the second embodiment, the case in which the print defect confirmation line 203 is printed in a light color with a density of 30% to 60% was described, but dark color printing is also acceptable. In this case, in order to suppress damage to the thermal head 102, the width (length in the paper feed direction) of the print defect detection line 203 is set to 2 mm or more, 8 mm or less, preferably 5 mm. In this way, by reducing the density of the print defect check line 203 with light-colored printing, or by shortening the print length with dark-colored printing of 2mm to 8mm, damage to the thermal head 102 can be effectively suppressed even if the print defect check line 203 is printed frequently, such as with each receipt issuance.

[0056] <Regarding reading the printout for checking for printing defects> Next, a third embodiment of printer 1 will be described. In the first and second embodiments, the user of the printer 1 discovers a blank space in the print, and a cleaning print pattern is printed by the user pressing the cleaning button. In contrast, the third embodiment automatically detects white areas in the print and automatically performs cleaning prints using a cleaning print pattern. In contrast, the printer 1 of the third embodiment automatically detects white gaps in the printed print defect confirmation line 203, similar to the second embodiment and its modified form, and automatically performs cleaning printing using a cleaning print pattern. Please note that group number 204 and group divider line 205 will not be printed due to automatic recognition.

[0057] The printer 1 of the third embodiment includes a reading unit for detecting white areas. The reading unit is located between the cutting unit 103 and the paper ejection unit 30 (see Figure 1) and is, for example, an optical sensor or a reflective sensor. Alternatively, the reading unit may be located between the thermal head 102 and the cutting unit 103. Furthermore, a print defect confirmation program is stored in the storage unit 50 of the printer 1 and is executed by the control unit 40 each time a print defect confirmation line 203 is printed. In other words, the reading unit reads the print defect confirmation line 203 printed on the paper to be printed 201 and temporarily stores it in RAM. The control unit 40 determines whether or not there are any blank spaces in the reading result stored in RAM (functioning as a non-print detection means). The control unit 40 prints a cleaning print pattern if it detects a white gap in the print defect confirmation line 203. At this time, the control unit 40 identifies the group corresponding to the area that needs cleaning from the detected white gap and prints the cleaning print pattern described in Figure 11 for that group. Alternatively, the heat-generating element 1021 that is the target of the white defect may be identified, and a cleaning print pattern may be printed on that heat-generating element 1021, or on that heat-generating element and several heat-generating elements on either side of it. According to the third embodiment, by automatically detecting areas that need cleaning and printing a cleaning pattern for the corresponding areas, the burden on the user in detecting white spots and the load on the thermal head 102 can be reduced.

[0058] Based on the embodiments and modifications described above, the printer 1 can be configured as follows. (Configuration 1) A printer that prints on paper by generating heat from heating elements arranged on a thermal head, A print data acquisition means for acquiring print data to be printed on the paper to be printed, A pattern acquisition means for acquiring a cleaning print pattern in which multiple print settings are defined in the paper feeding direction for cleaning the heating element by printing on the paper to be printed, The system includes a printing control means that generates heat in the heating element according to the acquired print data or cleaning print pattern, and prints on the paper to be printed, The cleaning print pattern acquired by the pattern acquisition means is defined as a print pattern that prints a dark color at a density that causes the dirt adhering to the heating element to exceed its melting temperature by continuously printing a predetermined length L or less. A printer characterized by the following features. (Configuration 2) The dark color printing is such that the density is 95% or more and 100% or less, when the highest density printing by the thermal head is considered to be 100%. The printer according to configuration 1, characterized by the features described above. (Configuration 3) The predetermined length L to be printed continuously by the dark color printing is a length that reaches the temperature necessary for the dissolution of the dirt and does not exceed a length that may damage the heating element. A printer according to configuration 1 or configuration 2, characterized by the above. (Configuration 4) The predetermined length L to be continuously printed by the dark color printing is 20 mm or more, which is necessary for the dissolution of the dirt, and is within the range of 100 mm or less, which does not exceed the length that may damage the heating element. A printer according to configuration 1, configuration 2, or configuration 3, characterized by the above. (Configuration 5) The cleaning print pattern is, Preheat printing with a concentration of 60% or more and less than 95% to preheat the aforementioned stain is specified before the dark-colored printing. The combined length of the preheated printing and the dark-colored printing is 100 mm or less, preferably 50 mm or less. A printer according to any one of the configurations 1 to 4, characterized by the above. (Configuration 6) The pattern acquisition means acquires a cleaning print pattern having a print pattern for each heating element that is divided into a plurality of groups. A printer according to any one of the configurations 1 to 5, characterized by the above. (Configuration 7) The cleaning print pattern is defined such that the dark prints in each group of print patterns do not overlap in a direction perpendicular to the paper feed direction. A printer according to the configuration described in configuration 6, characterized by the features described therein. (Configuration 8) The cleaning print pattern is defined such that, with respect to the dark print in each group's print pattern, the areas located in front of, to the left, to the right, and diagonally are defined as prints with a lower density than the dark print or no print at all. The printer according to configuration 6 or configuration 7, characterized by the above. (Configuration 9) The print control means further generates heat from all heating elements simultaneously to print on the paper to be printed for confirmation of printing defects. A printer according to any one of configurations 1 to 8, characterized by the above. (Configuration 10) The print control means performs printing for checking for printing defects before or after printing using the acquired print data. The printer according to configuration 9, characterized by the features described therein. (Configuration 11) The configuration includes a non-printing detection means for detecting the presence of non-printed areas in the printed print for checking printing defects, The print control means, when it detects a non-printed area using the non-printing detection means, prints on the paper to be printed using the cleaning print pattern. The printer according to configuration 9 or configuration 10, characterized by the above. (Configuration 12) The non-printing detection means detects non-printed areas in the printed print for checking printing defects, The printing control means performs printing on the heating element corresponding to the detected non-printed area according to the printing pattern. The printer according to configuration 11, characterized by the features described above. (Configuration 13) comprising a designation means for designating one or more of the aforementioned groups, The print control means performs printing according to the print pattern corresponding to the designated group. The printer according to configuration 6, characterized by the features described above. (Configuration 14) The printer is used in restaurants, A printer according to any one of configurations 1 to 13, characterized by the features described above. (Configuration 15) The computer is made to function as a printer as described in any one of Configurations 1 to 13. A printer program characterized by the following features. (Configuration 16) A storage medium characterized by storing a program for causing a computer to function as a printer according to any one of Configurations 1 to 13. (Configuration 17) A printer that prints on paper by generating heat from heating elements arranged on a thermal head, A print data acquisition means for acquiring print data to be printed on the paper to be printed, The system includes a printing control means that generates heat in the heating element according to the acquired printing data, thereby printing on the paper to be printed, The print control means performs a printout on the paper to be printed by heating all heating elements either before or after the printing area based on the print data, or separately from the printing based on the print data, to check for printing defects. A printer characterized by the following features. (Configuration 18) The configuration includes a pattern acquisition means for acquiring a cleaning print pattern in which multiple print settings are defined in the paper feeding direction for cleaning the heating element by printing on the paper to be printed, The printing control means generates heat in the heating element according to the acquired printing data or cleaning printing pattern, and prints on the paper to be printed. The printer according to configuration 17, characterized by the features described above. [Explanation of Symbols]

[0059] 1 Printer 10 Printer mechanism 20 Paper storage section 30 Paper output section 101 Conveyor unit 102 Thermal head 103 Cutting section 201 Printing paper 1021 Heating element 1022 Driver IC 40 Control unit 50 Storage unit 60 Display unit 70 Input unit 80 Communication section L, L1~L6 Cleaning print length Groups g1-g6, 202 receipts 202a Standard print data 202b Food and beverage data 203 Print defect check line 204 Group number 205 Group dividing line 206 White space

Claims

1. A printer that prints on paper by generating heat from heating elements arranged on a thermal head, A print data acquisition means for acquiring print data to be printed on the paper to be printed, A pattern acquisition means for acquiring a cleaning print pattern in which multiple print settings are defined in the paper feeding direction for cleaning the heating element by printing on the paper to be printed, The system includes a printing control means that generates heat in the heating element according to the acquired print data or cleaning print pattern, and prints on the paper to be printed, The cleaning print pattern acquired by the pattern acquisition means is defined as a print pattern that prints a dark color at a density that causes the dirt adhering to the heating element to exceed its melting temperature by continuously printing a predetermined length L or less. A printer characterized by the following features.

2. The aforementioned dark-colored printing has a density of 95% or more and 100% or less, when the maximum density printing by the thermal head is considered to be 100%. The printer according to feature 1.

3. The predetermined length L to be continuously printed by the dark-color printing is a length that reaches the temperature necessary for the dissolution of the dirt and does not exceed a length that may damage the heating element. The printer according to feature 1.

4. The predetermined length L to be continuously printed by the dark-colored printing is 20 mm or more, which is necessary for the dissolution of the dirt, and is within the range of 100 mm or less, which does not exceed the length that may damage the heating element. The printer according to feature 1.

5. The aforementioned cleaning print pattern is: Preheat printing with a concentration of 60% or more and less than 95% to preheat the aforementioned stain is specified before the dark color printing. The combined length of the preheated printing and the dark-colored printing is 100 mm or less, preferably 50 mm or less. The printer according to feature 1.

6. The pattern acquisition means acquires a cleaning print pattern having a print pattern for each heating element that is divided into multiple groups. The printer according to feature 1.

7. The cleaning print pattern is defined such that the dark prints in each group of print patterns do not overlap in a direction perpendicular to the paper feed direction. The printer according to feature 6.

8. The cleaning print pattern is defined such that, with respect to the dark print in each group of print patterns, the areas located in front of, to the left, right, and diagonally are defined as having a lower density of print or being unprinted. The printer according to feature 6.

9. The print control means further generates heat from all heating elements simultaneously to print on the paper to be printed for confirmation of printing defects. The printer according to feature 1.

10. The print control means performs the printing for checking for printing defects before or after printing using the acquired print data. The printer according to feature 9.

11. The system includes a non-printing detection means for detecting the presence of non-printed areas in the printed print for checking printing defects, The print control means, when it detects a non-printed area using the non-printing detection means, prints on the paper to be printed using the cleaning print pattern. The printer according to feature 9.

12. The non-printing detection means detects non-printed areas in the printed print for checking printing defects, The printing control means performs printing on the heating element corresponding to the detected non-printed area according to the printing pattern. The printer according to feature 11.

13. The system includes a designation means for designating one or more of the aforementioned groups, The print control means performs printing according to the print pattern corresponding to the designated group. The printer according to feature 6.

14. The aforementioned printer is used in restaurants. The printer according to any one of claims 1 to 13, characterized in that it is the same as the printer described in claim 1.

15. A computer is made to function as a printer according to any one of claims 1 to 13. A printer program characterized by the following features.

16. A storage medium characterized by storing a program for causing a computer to function as a printer according to any one of claims 1 to 13.

17. A printer that prints on paper by generating heat from heating elements arranged on a thermal head, A print data acquisition means for acquiring print data to be printed on the paper to be printed, The system includes a printing control means that generates heat in the heating element according to the acquired printing data, thereby printing on the paper to be printed, The print control means performs a printout on the paper to be printed by heating all heating elements either before or after the printing area based on the print data, or separately from the printing based on the print data, to check for printing defects. A printer characterized by the following features.

18. The system includes a pattern acquisition means for acquiring a cleaning print pattern in which multiple print settings are defined in the paper feeding direction for cleaning the heating element by printing on the paper to be printed, The printing control means generates heat in the heating element according to the acquired printing data or cleaning printing pattern, and prints on the paper to be printed. The printer according to feature 17.

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