JP2011056874A - Line printer and control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent heat storage of a heating element when printing a symbol image such as a ladder bar code or a two-dimensional code, thereby printing the symbol image which can be exactly read. <P>SOLUTION: The control method for the line printer includes a step 35 of determining whether a command received from a host computer 200 is a symbol command D for printing the ladder bar code, and a step S41 of printing the ladder bar code by decreasing printing speed when printing the ladder bar code, if it is determined that the command is the symbol command D (Yes: step S35). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a line printer communicably connected to a host computer and a control method thereof.

  A thermal head having a heating element is provided, and the printing paper is conveyed while being pressed against the heating element (printing element) of the thermal head, and a voltage is selectively applied to the heating element to generate heat so that any part of the printing paper A line thermal printer is known that forms a print image on a printing paper by heating (see Patent Document 1).

  A line thermal head in which one heating element is arranged in the width direction orthogonal to the printing paper conveyance direction can print the printing dots formed by one heating element by applying a single voltage in the width direction. .

  Incidentally, some of the line thermal printers described above print symbol images such as barcodes and two-dimensional codes. The bar code displays predetermined information by a combination of a bar and a space (interval between bars), and is restored (decoded) into information by being read by a bar code scanner. Therefore, when printing a barcode, it is necessary to convert (encode) information to be displayed into a barcode and print the barcode pattern. The same applies to a two-dimensional code displayed by a matrix or the like. In order to display predetermined information by a combination of black and white patterns arranged in a matrix, the information to be displayed is converted into a matrix code pattern and printed.

As described above, when printing a symbol image, it is necessary to ensure a certain print quality so that a reading error does not occur when it is read by a barcode scanner.
There is also an increasing demand for a free layout of barcodes on printed materials. For example, as shown in FIG. 12, a bar code in which a plurality of bars are formed in a direction orthogonal to the conveyance direction X of the print medium P, or a so-called ladder bar code 300 in which bars are arranged in a ladder-like direction. There is also a request to make a simple print.

JP 2007-55239 A

However, when the ladder barcode 300 is printed by the line head H in which the heating elements (printing elements) are arranged in the direction orthogonal to the transport direction X, that is, the same direction as the direction in which the heating elements of the line head H are arranged. When printing a bar in the direction, the same heating element Ha is always driven continuously for the width of the bar. Furthermore, since the ladder barcode 300 is formed to be relatively long by the number of characters and numbers encoded along the transport direction X, the drive time for the same heating element Ha becomes long although a space is included in the middle. For this reason, the heat generating element Ha in the portion where the bar is printed easily stores heat, and in the final printing stage of the ladder barcode 300, the printing paper is colored to the periphery of the heating element due to the heat storage, resulting in the bar becoming thick and accurate. In some cases, a bar having a small thickness cannot be formed. That is, although a thin bar should be printed, a bar thicker than usual may be printed due to the heat storage of the heat generating element Ha.
If the thickness of the bar changes, a reading error occurs when it is read by a barcode scanner.

  The above situation often occurs especially when printing a ladder barcode bar or a two-dimensional code dot, but it may also occur when printing a normal barcode as well as a ladder barcode. There is.

  The present invention has been made in order to solve the above-described problems, and when printing a symbol image such as a ladder bar code or a two-dimensional code, the heat generating element is prevented from accumulating heat and accurately read. An object of the present invention is to provide a line printer capable of printing a symbol image that can be printed and a control method for the line printer.

The present invention capable of solving the above problems is a line printer including a print head that is connected to a host computer so as to be communicable and includes a plurality of printing elements in a direction orthogonal to a conveyance direction of a print medium.
It is determined whether a command received from the host computer is a specific command for printing a specific symbol image. If it is determined that the command is the specific command, the printing speed is reduced when the symbol image is printed. And a print control unit for printing.
According to the above configuration, when it is determined that the received command is a specific command for printing a symbol image such as a ladder bar code or a two-dimensional code, when printing the symbol image, the printing speed or characters so far The printing speed is reduced compared to when printing. For this reason, it is possible to increase the cooling time by extending the drive interval for the printing element (heat generating element). Therefore, when printing a symbol image such as a ladder barcode or a two-dimensional code, it is possible to prevent the heat generating elements from accumulating heat and print a symbol image having a bar or dot size that can be read accurately. it can.

In the invention, it is preferable that the print control unit performs printing at a reduced printing speed in a print area including the symbol image.
According to the above configuration, since the area where the printing speed is reduced is limited, it is possible to prevent the throughput of the printing process from being extremely reduced.

In the present invention, the print head is divided into a plurality of blocks in which a printing element of at least one dot line can be varied,
The print control unit drives one dot line in a plurality of blocks.
According to the above configuration, since one dot line is driven in a plurality of blocks, the number of blocks of printing elements that are driven simultaneously is reduced, and power consumption is not increased rapidly. In particular, when printing a symbol image having a high density, since a relatively large number of printing elements tend to be driven at a time, a voltage drop or a voltage fluctuation is likely to occur due to a sudden increase in power consumption. These result in a printing result with low density or unevenness. According to the present invention, the printing element is divided and driven, so that power consumption can be dispersed and printing thinness and unevenness due to power drop and voltage fluctuation can be prevented.

Further, in the present invention, the symbol image is a ladder barcode in which each bar is printed in a direction orthogonal to a conveyance direction of the print medium,
The specific command includes a first command for designating a predetermined data development area on a memory and for developing data including the ladder barcode in the designated data development area.
Specify the specified data development area on the memory, replace the memory address with the XY coordinates in the printing mode after dot data (data that can be driven by the print head) is developed in the specified data development area. This is called a page mode because data is developed at a predetermined position on the page. Printing a ladder bar code or a two-dimensional code with a line printer is often performed in a normal page mode because it can be developed in a free layout at an arbitrary position on the page. On the other hand, a mode in which printing is started when dot data for one dot line is expanded is called a standard mode. In the page mode, unlike the standard mode, a data development area can be defined in advance and the print direction and the like can be designated, so that a free layout can be printed. Therefore, this mode is also used when printing a special symbol image such as a ladder bar code or a two-dimensional code. In particular, when a character or image is printed next to a ladder barcode or a two-dimensional code, the development process can be facilitated by using the page mode.
According to the above configuration, a specific data expansion area is designated on the memory, the specific command including the first command for expanding the data including the ladder barcode in the designated data expansion area is received, and the ladder is received. When printing the barcode, the printing speed is reduced. Therefore, it is possible to ensure the printing quality of the ladder barcode and prevent the reading error from occurring.

In the present invention, the symbol image is a two-dimensional code,
The specific command includes a first command for designating a predetermined data development area on a memory and developing data including the two-dimensional code in the designated data development area.
According to the above configuration, the two-dimensional code can be printed with a free layout in the page mode, and the printing speed is reduced when the two-dimensional code is printed. Therefore, it is possible to ensure the printing quality of the two-dimensional code and suppress the occurrence of a reading error.

In addition, the present invention that can solve the above-described problems is a control of a line printer that includes a print head that is communicably connected to a host computer and includes a plurality of printing elements in a direction perpendicular to the conveyance direction of the print medium. A method,
A step of determining whether a command received from the host computer is a specific command for printing a specific symbol image; and if it is determined that the command is the specific command, the printing speed is reduced when the symbol image is printed. And printing.
According to the above configuration, if it is determined that the specific command is for printing a symbol image such as a ladder bar code or a two-dimensional code, the print speed is automatically increased as compared with the previous print speed or character printing. To reduce. For this reason, it is possible to increase the cooling time by increasing the drive interval for the printing element, and it is possible to prevent the printing element from accumulating heat. Therefore, when printing a symbol image such as a ladder barcode or a two-dimensional code, it is possible to prevent the heat generating elements from accumulating heat and print an accurate symbol image having a bar or dot size.

1 is an external perspective view of a printer according to the present invention. FIG. 2 is a perspective view illustrating a state where a roll paper cover of the printer illustrated in FIG. 1 is opened. FIG. 2 is a block diagram illustrating an internal configuration of the printer according to the embodiment. It is the figure which showed the allocation table of the effective data element which comprises each division | segmentation block. It is a block diagram which shows the heat generating element of a print head, and its control circuit. FIG. 6 is a schematic diagram illustrating a heating element and a printing result when the print head is not driven in a divided manner. It is the schematic diagram which showed the heat generating element at the time of driving a print head divided into 2 parts, and the printing result. It is the schematic diagram which showed the heat generating element at the time of driving a print head divided into 3 parts, and the printing result. It is the schematic diagram which showed the heat generating element at the time of driving a print head divided into four, and a printing result. It is a flowchart which shows the process performed when the printer of this embodiment receives the symbol command which prints a two-dimensional code. 4 is a flowchart illustrating processing performed when the printer of the present embodiment receives a symbol command for printing a ladder barcode. It is the figure which showed an example of the ladder barcode.

  Embodiments of a line printer and a method for controlling the line printer according to the present invention will be described below with reference to the drawings.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A line thermal printer 100 according to the present embodiment (hereinafter referred to as “printer 100”) includes a roll paper cover 13 in the printer main body 11. The printer main body 11 is covered with a main body case 15 as an exterior. The main body case 15 and the roll paper cover 13 are each formed in a substantially box shape using resin. The printer 100 can select either a vertical installation or a horizontal installation. The printer 100 shown in FIG. 1 and FIG. 2 shows a state in which it is placed horizontally. In the present embodiment, the printer main body 11 is referred to as a bottom portion 17, one side wall is referred to as a front wall portion 19, and the other side wall is referred to as a rear wall portion 21 on the basis of a horizontally placed state. In addition, when the printer 100 is set vertically, the rear wall portion 21 is placed on the bottom side, and the front wall portion 19 becomes the top surface.

  The upper surface portion 23 of the printer 100 is provided with a paper discharge port 25 as an outlet, and the end portion of the printed roll paper is discharged from the paper discharge port 25. The upper surface portion 23 includes a roll paper cover 13 and a front portion 27 of the printer main body 11. The outer wall surface 13a of the roll paper cover 13 and the outer wall surface 27a of the front portion 27 are coplanar. The roll paper cover 13 is attached to the printer body 11 so as to be openable and closable around the rear wall 21 side. The paper discharge port 25 is formed between the open / close tip of the roll paper cover 13 and the front portion 27.

FIG. 2 is a perspective view showing a state in which the roll paper cover of the printer shown in FIG. 1 is opened.
Of the peripheral edge portion of the roll paper cover 13, bearing portions 29 are formed at both end portions on the rear wall portion 21 side. The bearing portion 29 constitutes a hinge 31 of the roll paper cover 13 together with a shaft portion on the printer main body 11 side (not shown) on both sides thereof. Thereby, the roll paper cover 13 is supported by the printer body 11 so as to be freely opened and closed.

  Inside the printer main body 11, a roll paper holder 33 capable of storing roll paper is provided. The roll paper holder 33 has a curved bottom portion and a pair of flat side portions 35 formed so as to sandwich the bottom portion, and is formed in a substantially box shape. A tension member is provided at the end of the roll paper holder 33 on the front portion 27 side. The tension member is configured to be swingable so as to give a predetermined tension to the piece of paper to be delivered drawn from the roll paper.

  A platen roller 37 is provided on the lower surface of the roll paper cover 13. A print head 44 (see FIG. 3) is provided in front of the roll paper holder 33. The print head 44 is disposed in a portion between the roll paper holder 33 and the front portion 27 in the printer main body 11. The platen roller 37 is disposed so as to face the print head 39 in a state where the roll paper cover 13 is closed, and sandwiches the sending paper piece. By driving the print head 44 in this state, the printer 100 performs printing on the roll paper.

  The platen roller 37 is provided on the platen holder 38 of the platen unit 39. The platen unit 39 has a release lever mechanism 32 (see FIG. 1). The release lever mechanism 32 includes a pair of engagement claws 36, 36 that swing on the platen holder 38 via a support shaft, and a release lever 34 that can be interlocked with one of the engagement claws 36, 36 (FIG. 1). Reference). The release lever mechanism 32 engages or disengages the roll paper cover 13 with respect to the main body case 15 in a closed state.

The internal configuration of the printer 100 according to this embodiment will be described.
As shown in FIG. 3, the printer 100 includes a paper transport device 41, a printer control unit 42, a print head 44, a temperature detection device 46, a voltage detection device 48, and an interface 50. The printer 100 is connected to the interface 201 of the host computer 200 via the interface 50.

  From the host computer 200, print data to be executed by the printer 100, control commands for controlling the printer 100, various setting values of the printer 100, and the like are transmitted.

  The paper transport device 41 includes a platen roller 37 that contacts a roll paper that is a print paper together with the print head 44 and transmits a transport force, and a paper transport motor 45 that drives the platen roller 37 via a transmission mechanism. . The print head 44 is a line thermal head in which a plurality of heating elements 44a (printing elements) are arranged in a straight line (one dot line), and generates heat by applying a predetermined energizing time voltage to the heating elements 44a. The portion of the roll paper that is in contact with the heating element 44a is heated and colored to form a printed image. The temperature detection device 46 measures the environmental temperature of the printer 100, particularly the temperature of the atmosphere of the print head 44. The temperature detection device 46 may be mounted on the print head 44. The voltage detection device 48 measures the voltage applied to the print head 44. The printer control unit 42 performs overall control of the components such as the print head 44 and the paper transport device 41 that constitute the printer 100 and the operation of each device.

  The printer control unit 42 includes a command analysis unit 47, a print buffer 49, a print control unit 51, a symbol data storage unit 52, a setting storage unit 53, an energization time determination unit 55, a transport control unit 57, and a transport. A motor drive unit 59 and a print head drive unit 61 are provided.

The command analysis unit 47 analyzes the data received from the host computer 200. If the command is a control command, the command analysis unit 47 transfers the print command to the print control unit 51. Expand to.
A page buffer 49a and a line buffer 49b are allocated to the print buffer 49 of this embodiment. The page buffer 49a is a memory, and is a buffer in which a predetermined data development area is defined in units of pages by a page mode command received from the host computer 200. On the other hand, the line buffer 49a is a buffer in which dot data for at least one dot line of the heating element 44a provided in the print head 44 is developed. A print line unit may be used.

The print control unit 51 constitutes a standard mode print processing unit 56 and a page mode print processing unit 58. In the initial setting, the standard mode print processing unit 56 can process. In response to the control command, the standard mode print processing unit 56 controls the driving of the paper transport device 41 via the transport control unit 57 and the transport motor drive unit 59 to transport the roll paper. Further, the drive of the print head 44 is controlled via the print head drive unit 61 to form print dots on the roll paper, and a print image is formed on the roll paper. That is, printing and conveyance are repeated for each dot line based on the dot data developed in the line buffer 49b.
On the other hand, when a page mode command (first command) is received from the host computer 200, the page mode print processing unit 58 can be processed. The page mode command is expressed as, for example, (ESC P X, Y), where (ESC) is a command, (P) is a page mode designation, and (X, Y) is an argument that defines a data development area. The page mode print processing unit 58 defines the page size in the XY direction of the data development area in the page buffer 49a based on the argument of the page mode command, and the received data at the designated position in the XY direction of the data development area. After all are expanded, print processing is executed in units of pages. That is, the page mode print processing unit 58 controls the transport control unit 57, the transport motor drive unit 59, and the print head drive unit 61 to take out each dot line based on the dot data developed in the page buffer 49a. Repeat printing and transport. When the standard mode is set, for example, it is expressed as (ESC S), (ESC) is a command, and (S) is configured by specifying the standard mode.

  The symbol data storage unit 52 stores symbol data corresponding to the symbol code. When a symbol command (a specific command including a page command) for printing a symbol image such as a two-dimensional code or a ladder barcode is received from the host computer 200, the standard mode print processing unit 56 or the page mode print processing unit 58 displays the symbol. Data is read out, dot data is generated and developed in the print buffer 49. The command analysis unit 47 may encode and generate symbol data of a two-dimensional code, bar code, or ladder bar code to be printed based on the received symbol command.

The setting storage unit 53 stores a table for distributing the heating elements 44a to the respective divided blocks according to the number of divisions. Here, the print head 44 has 576 heating elements 44a per dot line, and each heating element 44a corresponds to one of a plurality of variable divided blocks.
Specifically, as shown in FIG. 4, when one dot line is not divided, that is, when one dot line is divided, all the heat generating elements 44a of # 1 to # 576 are effective data elements (heat generating elements 44a corresponding to blocks). It becomes.
When one dot line is divided into two, the heating element 44a is provided in the first divided block in which # 1 to # 288 are effective data elements and in the second divided block in which # 289 to # 576 are effective data elements. Allocated.
In the case of three divisions, the first divided block having effective data elements from # 1 to # 192, the second divided block having effective data elements from # 193 to # 384, and the effective data elements from # 385 to # 576 The heating element 44a is allocated to the third divided block.
In the case of four divisions, the first divided block with effective data elements from # 1 to # 144, the second divided block with effective data elements from # 145 to # 288, and the effective data elements from # 289 to # 432 The heating element 44a is allocated to the third divided block, and the fourth divided block having # 433 to # 576 as effective data elements.

  Upon receiving a division drive command (ESC An) designating the number of divisions from the host computer 200, the print control unit 51 recognizes that the command is a command at (ESC), and determines that it is a division drive command at (A). And the number of divisions is recognized in (n). Each division block corresponding to the division number (n) can be acquired from the distribution table in the setting storage unit 53 in correspondence with the effective data element information. The print control unit 51 assigns the heating element 44a to each divided block based on the effective data elements corresponding to the number of divisions. (N) can be specified to be divided into 1 to 4 blocks as described above, and corresponds to the number of divisions, each block divided according to the number of divisions, and each block. The effective data element thus identified can be specified.

  The energization time determination unit 55 determines the temperature of the atmosphere of the print head 44 measured by the temperature detection device 46, the voltage applied to each heating element 44a of the print head 44 measured by the voltage detection device 48, and the divided drive command (ESC). An energization time for energizing each heating element 44a by applying a voltage is determined from the number of divisions specified by An). In consideration of applying the same energy, the energization time is shortened as the temperature measured by the temperature detection device 46 is higher, and the energization time is shortened as the voltage measured by the voltage detection device 48 is higher. When the number of divisions is small, the energization interval is shortened, and the time for the print head 44 to cool is shortened, so that the energization time can be shortened.

The conveyance control unit 57 controls the operation of the paper conveyance device 41 via the conveyance motor drive unit 59 in accordance with a command from the print control unit 51. When the number of divisions is designated by the division drive command (ESC An), the transport amount corresponding to the number of divisions is calculated.
The transport motor drive unit 59 drives the paper transport motor 45 in accordance with a command from the transport control unit 57 to transport the roll paper.
The print head drive unit 61 drives the print head 44 by applying a voltage to the heating element 44 a of the print head 44 in accordance with a command from the print control unit 51.
In addition, a division drive command for designating the number of divisions may be transmitted from the host computer 200, such as when changing from logo to text printing during printing. The print control unit 51 divides the heating element 44a into each divided block based on the effective data elements corresponding to the number of divisions, and performs energization control. The conveyance control unit 57 controls the conveyance amount of the paper conveyance device 41 via the conveyance motor drive unit 59 based on a command according to the number of divisions from the print control unit 51. In this case, if the carry amount is suddenly changed, the paper carry motor 45 may vibrate or step out in some cases. The conveyance control unit 57 smoothly changes the conveyance amount for a predetermined distance according to the division number, such as slowing up or slowing down when the division number changes.

Next, the function of the print head drive unit 61 will be described.
As shown in FIG. 5, each of the heat generating elements # 1 to #n indicates one of the heat generating elements 44a of the print head 44 to which the print head driving unit 61 is connected.

  In the print head 44, resistors R1 to Rn are connected to a common electrode 63, and each resistor R serves as a heating element 44a. The common electrode 63 is connected to the head supply power source 71. Each resistor R is individually connected to the heating element 44a through the individual electrode 65 to the switching elements A1 to An in the driver IC 67. The output terminal of each switching element A is connected to the STROBE terminal of the control circuit 69. L1 to Ln are latch circuits corresponding to the respective resistors R, and are connected to the LATCH terminal. Each of S1 to Sn is a shift register cell corresponding to each resistor R, and is connected in series to constitute a shift register. The shift register is connected to the CLOCK terminal and the DATA IN terminal.

A serial print signal designating ON (energized) or OFF (non-energized) of the heating element 44a for one dot line is developed in the print buffer 49, and the dot data developed in the print buffer 49 is the DATA of the head control circuit 69. Input from IN to shift registers S1 to Sn. The shift registers S1 to Sn convert the input serial print signal into a parallel print signal in synchronization with the CLOCK signal input from the clock terminal CLOCK, and output the parallel print signal to the latch circuits L1 to Ln. The latch circuits L1 to Ln latch parallel data for one dot line by a pulse signal input from the latch input terminal LATCH. Switching elements A1 to An are connected to the respective heating elements 44a, and the heating elements 44a are driven by the strobe signal input from the STROBE terminal and the latch outputs output from the latch circuits L1 to Ln. More specifically, a voltage is applied to the heating element 44a that is ON-designated by the latch outputs that are output from the latch circuits L1 to Ln, and the energization is performed while the strobe signal is applied.
The head control circuit 69 is configured by a logic circuit that can select the latch circuits L1 to Ln and the switching elements A1 to An in units of blocks according to the designated number of divisions. Specifically, the number of latch outputs and strobe signals corresponding to the number of divisions can be output, and each latch output and strobe signal are output sequentially for each selected block in a predetermined order, corresponding to each block. Resistors R1 to Rn that are energized generate heat.

Next, the heating element 44a of the print head 44 and the printing dots formed by the heating element 44a will be described with reference to FIGS.
As shown in FIG. 6A, the heating elements 44a indicated by white circles are arranged in a line extending in a direction substantially orthogonal to the roll paper conveyance direction indicated by an arrow X.

  A heating element 44a indicated by a black circle in FIGS. 6B, 7A, 7B, 8A, 8B, 9C, 9A, 9B, 9C, 9D is shown. This indicates that the heating element 44a at that position is energized. FIG. 6B shows a case where the number of divisions is set to 1 and shows a state in which a strobe signal is applied to all 576 heating elements 44a and energized. When all of the 576 heating elements 39a are energized, as shown in FIG. 6 (c), a dot line 75 in which printing dots formed by energizing all the heating elements 44a are connected in a substantially straight line is printed. The Actual printing dots are substantially circular or substantially oval, and minute irregularities are formed on both sides of the dot line 75 that cannot be distinguished with the naked eye. By repeating the printing of one dot line, the solid print 75a is formed.

  FIGS. 7A and 7B show the case where the number of divisions is set to two. A strobe signal is applied to the heating elements 44a of 1 to 288 included in the first divided block, and the roll paper is conveyed by a half conveyance amount for one dot line. Next, a strobe signal is applied to the heating elements 44a of 289 to 576 included in the second divided block adjacent to the first divided block driven immediately before. For example, when the length L in the carrying direction of one dot is 0.125 [mm], the dot is applied by 0.125 / 2 [mm] and then applied to the heating element 44a of the second divided block. By thus driving the heating element 44a by dividing it into two divided blocks, as shown in FIG. 7C, the printing dots formed by energizing one heating element 44a are arranged in a substantially straight line. Dot lines 77 and 79 are printed.

  FIGS. 8A, 8B, and 8C show a case where the number of divisions is set to 3. FIG. A strobe signal is applied to the heating elements 44a of 1 to 192 included in the first divided block, and the roll paper is transported by a transport amount that is 1/3 of one dot line. Next, a strobe signal is applied to the heat generating elements 44a of 193 to 384 included in the second divided block adjacent to the first divided block that is driven immediately before, and again, only one third of the carry amount for one dot line is conveyed. Roll paper is conveyed. Further, a strobe signal is applied to the heating elements 44a of 385 to 576 included in the third divided block adjacent to the second divided block driven immediately before. That is, in the case of three divisions, the second divided block is energized after being conveyed by 0.125 / 3 [mm], and the third divided block is energized again after being conveyed by 0.125 / 3 [mm] again. . By thus driving the heating element 44a by dividing it into three divided blocks, as shown in FIG. 8D, the printing dots formed by energizing one heating element 44a are substantially linear. The continuous dot lines 81, 83, and 85 are printed.

  Similarly, FIG. 9A, FIG. 9B, FIG. 9C, and FIG. 9D show the case where the number of divisions is set to four. A strobe signal is applied to the heating elements 44a 1 to 144 included in the first divided block, and the roll paper is conveyed by a conveyance amount of a quarter of one dot line. Next, a strobe signal is applied to the heating elements 44a of 145 to 288 included in the second divided block adjacent to the first divided block that was driven immediately before, and again, only one-fourth of the carry amount for one dot line. Roll paper is conveyed. A strobe signal is applied to the heating elements 44a of 289 to 432 included in the third divided block adjacent to the second divided block that has been driven immediately before, and the roll paper is again transported by a quarter of the conveyance amount for one dot line. Be transported. Further, a strobe signal is applied to the heating elements 44a of 433 to 576 included in the fourth divided block adjacent to the third divided block driven immediately before. That is, in the case of four divisions, the second divided block is energized after being conveyed by 0.125 / 4 [mm], and the third divided block is energized again after being conveyed by 0.125 / 4 [mm] again. Then, after conveying again by 0.125 / 4 [mm], the fourth divided block is energized. By thus driving the heating element 44a by dividing it into four divided blocks, as shown in FIG. 9E, the printing dots formed by energizing one heating element 44a are substantially linear. The continuous dot lines 87, 89, 91, 93 are printed.

As described above, the printer 100 according to the present embodiment can reduce the printing speed by reducing the transport amount per time as the number of divisions increases. By performing the division driving, stepped bumps are formed between the dot lines formed by the divided blocks. However, if the number of divisions is increased, the bumps can be suppressed.
Furthermore, the strobe signal is not applied to all the heating elements 44a at a time, but is applied to each divided block, thereby preventing an increase in power consumption.

  Next, processing performed when the printer 100 of the present embodiment receives a symbol command from the host computer 200 will be described with reference to FIG. FIG. 10 shows a symbol image printing process when no page mode command is received, that is, in the standard mode.

  First, when the command analysis unit 47 of the printer 100 analyzes the data received from the host computer 200 and analyzes it as a control command by (ESC), it is transferred to the print control unit 51. When the standard mode print processing unit 56 determines that the received control command is a division drive command (An) that specifies the number of divisions of the heat generating element 44a (step S11: Yes), the distribution stored in the setting storage unit 53 is determined. By referring to the table, the effective data element information of each divided block is acquired according to the number of divisions (n) designated by the division drive command. In response to the instruction from the standard mode print processing unit 56, the transport control unit 57 calculates the transport amount of the roll paper from the designated number of divisions (step S13).

  Next, if it is determined that the received control command is a symbol command B (a specific command including a page command) for printing a two-dimensional code (step S11: No, step S15: Yes), it is designated by the symbol command B. The symbol image corresponding to the symbol code is read from the symbol data storage unit 52. The standard mode print processing unit 56 converts the symbol image into dot data, transfers it to the line buffer 49b, and develops it (step S17). The command analysis unit 47 may encode and generate two-dimensional code, bar code, or ladder bar code symbol data to be printed based on the received symbol command.

  On the other hand, when the received data is neither the division drive command (ESC An) nor the symbol command B (step S11: No, step S15: No), other processing is executed. For example, if the received data is a text code, the text data corresponding to the text code is expanded in the line buffer 49b. For other commands such as a line feed command, the print control unit 51 executes processing according to each command.

  In response to an instruction from the print control unit 51, the print head drive unit 61 latches the heating element 44a to be applied in the first divided block of one dot line based on the dot data developed in the line buffer 49b. The output and the strobe signal are selected and applied, the heating element 44a corresponding to the first divided block is selected, energized, and printed on the roll paper.

  After printing the first divided block, the conveyance control unit 57 controls the conveyance motor drive unit 59 to convey the roll paper by the conveyance amount calculated in step S13 (step S19). Next, the second divided block is selected, and the corresponding latch output and strobe signal are selected and applied to energize the heating element 44a corresponding to the second divided block, and after printing, the roll paper is conveyed again. . In this way, printing and conveyance are repeatedly executed for the designated number of divisions.

  Thereafter, steps S17 to S21 are repeatedly executed until all symbol images are developed and printing is completed (step S21: No). That is, the drive timing of each divided block divided into the number of divisions specified by the division drive command (ESC An) is shifted and driven, and the roll paper is conveyed by the conveyance amount corresponding to the number of divisions.

  When printing is completed (step S21: Yes), the heating element 44a can be set as one division in preparation for the next, without being divided.

  As described above, the printer 100 according to the present embodiment can print the two-dimensional code by driving the heating element 44a in accordance with the divided drive command (ESC An) received from the host computer 200. For this reason, the printing speed is reduced in the portion where the symbol image is printed in order to maintain the printing quality, while the normal printing speed can be returned in the portion where the text characters and the like are printed. A specific command including a split drive command (ESC An) can also be used. As described above, the specific command can be configured to include at least one of a symbol command B, a symbol command, a page command, and a divided drive command of a barcode or a two-dimensional code.

  In the above-described flow, the two-dimensional code is printed by driving the heating element 44a in accordance with the division drive command (ESC An). It is also possible to configure so that 44a is automatically divided and driven.

Further, it is not always necessary to perform the division driving, and it may be configured to automatically reduce the printing speed when the symbol command B is received.
For example, it is assumed that the printer 100 of the present embodiment has nine printing speeds and is set to the fastest level 9 in the initial setting. A specific maximum printing speed is set to 200 [mm / s]. Level 8 is 151 [mm / s], Level 7 is 125 [mm / s], Level 6 is 100 [mm / s], Level 5 is 78 [mm / s], Level 4 is 68 [mm / s], Level 3 is 57 [mm / s], Level 2 is 48 [mm / s], and Level 1 is 35 [mm / s]. Of these, if the printing speed suitable for symbol printing is set to a speed that does not exceed 100 [mm / s], for example, the standard mode print processing unit 56 automatically changes to the printing speed of level 5 when receiving the symbol command B. Thus, the printing process may be executed.

  Next, processing performed when the printer 100 of this embodiment receives a symbol command for printing a ladder barcode from the host computer 200 will be described with reference to FIG.

  First, when the command analysis unit 47 of the printer 100 analyzes the data received from the host computer 200 and analyzes it as a control command, it is transferred to the print control unit 51. When the print control unit 51 determines that the page mode command C (ESC P X, Y) is for shifting from the standard mode to the page mode (step S31: Yes), the page mode print control unit 58 is configured. The page mode print control unit 58 sets a data development area having a size (X, Y) designated by the page command in the page buffer 49a (step S33).

When the page mode print control unit 58 determines that the received command is a symbol command D for printing a two-dimensional code or a ladder barcode (step S31: No, step S35: Yes), the page mode print control unit 58 is designated by the symbol command D. The symbol image corresponding to the symbol code is read from the symbol data storage unit 52. Alternatively, the command analysis unit 47 may encode and generate a two-dimensional code, a barcode, or a ladder barcode symbol image to be printed based on the received symbol command. Then, the symbol image is converted into dot data, transferred to the page buffer 49a set in step S33, and developed (step S37).
The symbol command D includes values for specifying the ladder barcode printing position and the width and height of the ladder barcode. Therefore, the page mode print processing unit 58 develops a dot image in the page buffer 49a based on these values.

  When the development of the dot data in the page buffer 49a is completed and the print command E for printing the dot image in the page buffer 49 is received (step S31: No, step S35: No, step S39: Yes), the print head drive unit 61 In response to an instruction from the print controller 51, a strobe signal is applied to the heating element 44a to be applied based on the dot data developed in the page buffer 49a, and printing is performed on the roll paper. The conveyance control unit 57 controls the conveyance motor driving unit 59 to convey the roll paper (Step S41). Thereafter, printing and conveyance are repeatedly executed.

  When the received data is not any of the page mode command C, the symbol command D, and the print command E (step S31: No, step S35: No, step S39: No), other processing is executed. For example, if the received data is a text code, the text character corresponding to the code is developed in the page buffer 49a.

Here, in step S41, the page mode print processing unit 58 reduces the printing speed when printing the portion including the ladder barcode. That is, as described above, the heating element 44a is automatically divided and driven by a preset number of divisions to reduce the printing speed.
Further, it is not always necessary to drive the heating element 44a in a divided manner, and the printing speed can be automatically reduced to a predetermined level when a portion including the ladder barcode is printed.
Since the page mode print processing unit 58 knows the position of the ladder barcode in the page buffer 49a from the ladder barcode print position included in the symbol command D, the page mode print processing unit 58 determines whether the portion includes the ladder barcode. can do.

When the printing of all the dot data in the page buffer 49a is finished, the printing process is finished (step S43: Yes).
The specific command described in the claims includes a page mode command C and a symbol command D.

  As described above, the printer 100 according to the present embodiment can reduce the printing speed when the symbol command B for printing a two-dimensional code or the symbol command D for printing a ladder barcode is received. For this reason, the drive interval with respect to the heat generating element 44a can be lengthened and the cooling time can be lengthened, and the heat generating element 44a can be prevented from storing heat. Therefore, when printing a ladder bar code or a two-dimensional code, it is possible to prevent the same heating element 44a from accumulating heat and print a symbol image having an accurate size.

In addition, the area where the printing speed is reduced can be limited to only the portion including the symbol image. The printing speed is reduced by the portion of the ladder barcode 300 in FIG. For this reason, it is possible to prevent the throughput of the printing process from being extremely reduced.
Furthermore, since the plurality of heating elements 44a can be driven in a divided manner, there is no sudden increase or decrease in power consumption. When printing a two-dimensional code or a ladder bar code, it is necessary to drive a relatively large number of heating elements 44a at a time, so that power consumption tends to increase or decrease. By driving the heating element 44a in a divided manner, increase or decrease in power consumption can be suppressed as much as possible, and unevenness in printing thinness due to voltage drop or voltage fluctuation can be prevented.

41: paper transport device, 42: printer control unit, 44: print head, 44a: heating element, 45: paper transport motor, 46: temperature detection device, 47: command analysis unit, 48: voltage detection unit, 49: print buffer , 50, 201: I / F (interface), 51: print control unit, 52: symbol data storage unit, 53: setting storage unit, 55: energization time determination unit, 56: standard mode print processing unit, 57: transport control , 58: page mode print processing unit 58, 59: transport motor drive unit, 61: print head drive unit, 100: printer, 200: host computer.

Claims (6)

A line printer including a print head that is connected to a host computer in a communicable manner and includes a plurality of printing elements in a direction orthogonal to the conveyance direction of the print medium,
It is determined whether a command received from the host computer is a specific command for printing a specific symbol image. If it is determined that the command is the specific command, the printing speed is reduced when the symbol image is printed. A line printer comprising: a print control unit that performs printing.   The line printer according to claim 1, wherein the printing control unit performs printing by reducing the printing speed in a printing region including the symbol image. The print head is divided into a plurality of blocks that can change a printing element of at least one dot line,
The line printer according to claim 1, wherein the print control unit drives one dot line in a plurality of blocks. The symbol image is a ladder barcode in which each bar is printed in a direction perpendicular to the conveyance direction of the print medium,
The specific command includes a first command for designating a predetermined data development area on a memory and developing data including the ladder barcode in the designated data development area. The line printer according to any one of 1 to 3. The symbol image is a two-dimensional code,
The specific command includes a first command for designating a predetermined data development area on a memory and for developing data including the two-dimensional code in the designated data development area. The line printer according to any one of 1 to 3. A control method for a line printer including a print head that is connected to a host computer in a communicable manner and includes a plurality of printing elements in a direction orthogonal to a conveyance direction of a print medium,
Determining whether the command received from the host computer is a specific command for printing a specific symbol image;
And a step of printing at a reduced printing speed when printing the symbol image when it is determined that the command is the specific command.

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