JP2008012788A - Line printer and printing control method for line printer - Google Patents

Abstract

A line printer for setting an appropriate printing speed based on a baud rate of a communication interface and a printing control method for the line printer are proposed.
A line thermal printer includes a baud rate detecting means for detecting a baud rate of a communication interface. When the low baud rate is detected by the baud rate detecting means (step ST1), the upper limit value setting means sets a low printing speed as the upper limit value of the printing speed of the line thermal head (step ST3). Further, the drive control means controls the printing speed of the line thermal head and the conveyance speed of the recording paper so that the printing speed is equal to or lower than the set upper limit value, and performs printing (step ST5). When the baud rate is low, the printing speed of the line thermal head is slowed down, so that it is possible to avoid interruption of printing for every printing of one line of the line thermal head in order to wait for reception of print data.
[Selection] Figure 2

Description

  The present invention relates to a line printer that changes a printing speed according to a baud rate of a communication interface.

  As a printer that is connected to a register device in a store and prints an account statement or a coupon, a line thermal printer that performs printing line by line while conveying roll paper is widely used. In recent years, since the printing speed of line thermal printers has improved, when the communication speed of the communication interface connecting the register device and the line thermal printer is low, the print data transmitted from the register device is printed on the line. In some cases, the line thermal printer stops in a waiting state for receiving print data because the type print head is not ready for printing for each line.

When print data reception waits frequently and the line thermal printer repeats printing and stopping, the roll paper feed amount fluctuates before and after that. As a result, the printing pitch is disturbed and the printing density is changed to cause uneven printing, resulting in a deterioration in printing quality. In order to avoid such a problem, for example, Japanese Patent Application Laid-Open No. H10-228707 describes a technique for controlling the printing speed of a line printer from a host computer to prevent waiting for receiving print data. For example, Japanese Patent Application Laid-Open No. 2003-228561 describes a method in which a host computer controls the communication clock of a line printer to maintain a high communication speed between the two to prevent waiting for receiving print data.
JP 2003-50777 A JP-A-9-146724

  However, in the method of controlling the printing speed and communication clock of the line printer from the host computer side, it is necessary to install an application and hardware for controlling the line printer in the host computer.

  In view of these points, an object of the present invention is to provide a print control method for a line printer in which the line printer itself controls the print speed so that printing does not stop due to waiting for reception of print data. It is to propose. Another object of the present invention is to propose a line printer that performs printing by the printing control method.

  In order to solve the above problems, the present invention provides an initialization after driving power is turned on in a print control method of a line printer that prints print data received from the outside via a communication interface line by line by a line type print head. The line printer detects the baud rate of the communication interface at the point of time and / or at the start of reception of print data, and a print interruption state for waiting for reception of print data does not occur every print for one line. As described above, the line printer sets an upper limit value of the printing speed of the line type print head based on the baud rate.

According to the present invention, when a low baud rate is detected as the baud rate of the communication interface, the line printer itself sets the upper limit value of the print speed of the line type print head to slow down the print speed of the line type print head. be able to. As a result, it is possible to prevent printing from being interrupted every time one line of the line-type print head is waiting for reception of print data received via the communication interface. This prevents the printing pitch from being disturbed and the printing density from changing and causing printing unevenness, thereby maintaining the printing quality at a high quality.

  In the present invention, the line printer sets the upper limit value of the print speed of the line type print head to the first upper limit speed regardless of the baud rate when printing in a print mode that does not require reception of print data. Is preferred. In such a print mode, there is no need to wait for reception of print data, so that the first upper limit speed can be set to, for example, the maximum print speed originally provided in the line printer, and printing can be performed at high speed.

  In the present invention, when at least the first baud rate and the second baud rate lower than the first baud rate can be set as the baud rate of the communication interface, the upper limit value is preset in the case of the first baud rate. The second upper limit speed is set to a preset third upper limit speed in the case of the second baud rate, and the second upper limit speed is set to be lower than the first upper limit speed. The third upper limit speed may be lower than the two printing speeds.

  Here, as a print mode that does not require waiting for reception of the print data, there is a mode in which printing is started after the print data received via the communication interface is stored in the print buffer up to the break of the print data.

  In the present invention, the line type print head may be a line type thermal head. In the case of a thermal head, the print quality is significantly deteriorated due to the interruption of printing. Therefore, by adopting the present invention, such an adverse effect can be surely prevented.

  Next, the present invention provides a baud rate detecting means for detecting a baud rate of the communication interface in a line printer capable of printing print data received from the outside via a communication interface on a recording medium line by line by a line type print head; Upper limit setting means for setting an upper limit value of the printing speed of the line-type print head based on the detected baud rate so that a print interruption state for waiting to receive print data does not occur every time one line is printed; Drive control means for driving the line-type print head at a printing speed equal to or lower than a set upper limit value, and for carrying out printing by conveying the recording medium at a conveyance speed corresponding to the printing speed. And

  According to the line printer of the present invention, when the baud rate detecting unit detects a low baud rate, the upper limit value setting unit sets the upper limit value of the printing speed of the line type print head to be low. The drive control unit controls the printing speed of the line type print head and the conveyance speed of the recording medium so that the printing speed is equal to or lower than the set upper limit value. In this way, when the baud rate is low and the print data transfer speed is low, the line printer itself slows down the print speed, so printing is performed for each line of the line-type print head waiting to receive print data. Can be avoided. Therefore, it is possible to keep the printing quality high by avoiding fluctuations in the recording paper feed amount, disturbing the printing pitch, or changing the printing density and causing uneven printing.

Here, there is provided a print mode detection unit that detects whether or not the print mode does not require waiting for reception of print data, and the upper limit setting unit detects that the print mode is in effect. Regardless of the baud rate, it is preferable to set the upper limit value of the printing speed of the line type print head to the first upper limit speed set in advance. In such a print mode, there is no need to wait for reception of print data, so that the first upper limit speed is set to the maximum print speed originally provided by the line printer, for example, and printing can be performed at high speed. it can.

  The present invention stores and holds at least three types of upper limit values, ie, the first upper limit speed, the second upper limit speed lower than the first upper limit speed, and the third upper limit speed lower than the second upper limit speed. The communication interface can set the baud rate to at least a first baud rate and a second baud rate lower than the baud rate, and the upper limit setting means is configured to use the first baud rate. Preferably, the upper limit value is set to the second upper limit speed, and in the case of the second baud rate, the upper limit value is set to the third upper limit speed. When the upper limit value setting means sets the upper limit value of the printing speed, it can be selected from the first upper limit speed, the second upper limit speed, and the third upper limit speed printing speed that are stored in advance in the upper limit value storage unit. It becomes easy. In addition, by rewriting the upper limit value stored in the upper limit value storage unit, the upper limit value can be flexibly changed depending on the intended use of the line printer.

  Here, the print mode that does not require waiting for reception of the print data includes a mode in which the print data received via the communication interface is stored in the print buffer up to the end of the print data and then printing is started. be able to.

  In addition, when the communication interface includes a dip switch for setting the baud rate, the baud rate detecting means can detect the baud rate from the state of the dip switch. If the baud rate is detected from the state of the dip switch, it is not necessary to detect the baud rate by communicating with an external device connected via the communication interface. Therefore, the line printer itself can perform from the detection of the baud rate to the setting of the upper limit value of the printing speed of the line type print head without interposing an external device.

  Furthermore, the present invention can be applied to a line thermal printer provided with a line type thermal head as the line type print head.

  According to the line printer and the print control method of the line printer of the present invention, when it is detected that a low value is set as the baud rate of the communication interface, the line printer itself sets the upper limit of the print speed of the line type print head. The value can be set to slow down the printing speed of the line type print head. As a result, it is possible to prevent printing from being interrupted every time one line of the line-type print head is waiting for reception of print data received via the communication interface. This prevents the printing pitch from being disturbed and the printing density from changing and causing printing unevenness, thereby maintaining the printing quality at a high quality.

  Hereinafter, an embodiment of a line thermal printer to which the present invention is applied will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a line thermal printer of this embodiment. FIG. 2 is a flowchart showing an operation in which the line thermal printer sets the printing speed of the line thermal head based on the baud rate.

(Configuration of line thermal printer)
As shown in FIG. 1, the line thermal printer 1 of this embodiment is connected to a register device (host computer) 30 via a communication interface 2, and is based on thermal roll paper (recording) based on print data transmitted from the host computer 30. (Paper) 4 is used for printing accounting statements and coupons.

  The communication interface 2 is an RS-232C serial interface, and one of the baud rates defined as the RS-232C serial interface standard is selected and connected to the host computer 30. Yes. The baud rate is set in advance by a dip switch 5 provided in the main body of the line thermal printer 1. In this embodiment, baud rates that can be set include, for example, 57600 bps, 38400 bps, and 9600 bps.

  The line thermal printer 1 receives print data transmitted from the host computer 30 via the communication interface 2. The received print data is temporarily stored in the reception buffer 6. The print data stored in the reception buffer 6 includes character data and image data as well as control commands for specifying the print position and size of the print data and controlling the cutting and discharging of the recording paper 4. Therefore, the control unit 7 analyzes these control commands and generates print data for each line according to the print format by the line thermal head 8.

  The generated print data for each line is expanded and stored in the print buffer 9. In parallel with the development of the print data in the print buffer 9, the print data for each line already developed and stored in the print buffer 9 is read into the latch circuit 10. Then, it is sent from the latch circuit 10 to the line thermal head 8, and printing is performed for each line.

  When printing for one line by the line thermal head 8 is completed, the stepping motor 11 drives the platen roller 12 to convey the recording paper 4 for one line. When the conveyance is finished, the line thermal head 8 performs printing for the next one line. These operations are repeated until the print data is completed. The printing speed by the line thermal head 8 and the conveyance speed of the recording paper 4 by the stepping motor are controlled by the drive control means 13 of the control unit 7.

  Here, the control unit 7 has a baud rate detecting means 14 for detecting the baud rate set by the DIP switch 5 and an upper limit value setting for setting the upper limit value of the printing speed of the line thermal head 8 based on the detected baud rate. Means 15 and a print mode detection means 16 for detecting whether or not the print mode does not require waiting for reception of print data. When the upper limit value is set by the upper limit value setting means 15, the drive control means 13 drives the line thermal head 8 at a printing speed equal to or lower than the set upper limit value and controls the stepping motor 11 to record the recording paper 4. Is conveyed at a conveyance speed corresponding to the printing speed of the line thermal head 8.

  Further, inside the line thermal printer 1, an upper limit value storage unit 17 that stores and holds candidates for the upper limit value of the printing speed set by the upper limit value setting means 15, and a routine print when a coupon is issued. The image storage unit 18 stores graphic data such as a logo of a store or an advertisement.

  The upper limit storage unit 17 stores a plurality of printing speeds set as upper limit values for the printing speed of the line thermal head 8. One of the upper limit values is the maximum printing speed (first upper limit speed) that the line thermal head 8 originally has. The upper limit speed, which is another candidate for the upper limit value, is stored and held in a format related to the baud rate defined as the RS-232C serial interface standard.

(Print speed setting operation)
Next, an operation in which the line thermal printer 1 sets the upper limit value of the printing speed of the line thermal head 8 based on the baud rate will be described with reference to FIG.

When the line thermal printer 1 is turned on and the settings are initialized, the baud rate detection means 14 detects the baud rate of the communication interface 2 from the state of the dip switch 5 (step ST1). The timing for detecting the baud rate may be when communication with the host computer 30 is started.

  When the baud rate is detected, the print mode detection unit 16 determines whether or not the print mode does not require the reception of print data (step ST2). For example, there are the following three cases when it is determined that the print mode does not require reception of print data.

  The first case is when the print mode is the page mode. In the page mode, printing is started after the print data received via the communication interface 2 is stored in the print buffer 9 until the break of the print data. Therefore, the print data is not changed between the start of printing and the break when printing ends. Does not require waiting for reception. That is, in the normal print mode, the print data for each line obtained by analyzing the print data is read into the latch circuit 10 in parallel with being developed and stored in the print buffer 9. Printing is performed. For this reason, when the printing speed of the line thermal head 8 is high, the read timing by the latch circuit 10 is earlier than the timing at which the print data for each line is developed into the print buffer 9, and the print data Waiting to receive is required. On the other hand, in the page mode, the print data for each line obtained by analyzing the print data is expanded and stored in the print buffer 9 until the break of the print data, and then read by the latch circuit 10. Since printing is performed, there is no need to wait for reception of print data from the start of printing until the end of printing.

  The page mode is set by a page mode command included in the print data transmitted from the host computer 30. Accordingly, when the control unit 7 detects a page mode command in the print data, the print mode is maintained in the page mode until a page mode cancel command for canceling the page mode command is detected. Examples of commands that indicate print data breaks include a page break command, a recording paper 4 discharge command, and a cut command for cutting the recording paper 4 with an auto cutter. To be judged.

  The second case is a case of printing graphic data stored and held in advance in the image storage unit 18. The graphic data stored and held in the image storage unit 18 is printed by a graphic print command transmitted from the host computer 30.

  When the graphic print command is detected in the print data, the control unit 7 generates print data for each line from the graphic data in the image storage unit 18. The generated print data for each line is developed and stored in the print buffer 9 until the end (separator) of the graphic data, and is then read and printed by the latch circuit 10. Therefore, there is no need to wait for reception of print data from the start of printing until the end of printing. Therefore, after the control unit 7 detects the graphic print command, this print mode is maintained until the graphic data is printed.

  The third case is a case where graphic data transmitted from the host computer 30 is designated and printed in this print mode. The transmitted graphic data is printed in the normal print mode. When a mode designation print command is transmitted from the host computer 30, the graphic data stored and held in advance in the image storage unit 18 is printed. Similarly, after being developed and stored in the print buffer 9 until the end of the graphic data (delimiter), it is read by the latch circuit 10 and printing is performed. Therefore, after the control unit 7 detects the mode designation print command, this print mode is maintained until the graphic data designated by the command is printed.

  In step ST2 for determining the print mode, if it is determined that the print mode does not require the reception of print data, it is determined every time the line thermal head 8 prints for one line in order to wait for reception of the print data. A situation where printing is interrupted does not occur. Therefore, the upper limit setting unit 15 refers to the upper limit storage unit 17 and sets the maximum printing speed as the upper limit value of the printing speed of the line thermal head 8 (step ST4).

  If it is determined in step ST2 for determining the print mode that the print mode requires waiting for reception of print data, the upper limit setting means 15 is based on the baud rate detected in step ST1 for detecting the baud rate. Then, one upper limit speed is selected from a plurality of upper limit value candidates stored in the upper limit value storage unit 17, and is set as the upper limit value of the printing speed (step ST3).

  Here, when the specifications of the line thermal printer 1 of the present embodiment are, for example, resolution 203 dpi, 64 digits / line, 24 dots / line feed, and maximum printing speed 220 mm / s, the upper limit value storage unit 17 stores The following upper limit candidates are stored and held.

Maximum printing speed 220mm / s
Baud rate Maximum speed 57600bps 270mm / s
38400bps 180mm / s
9600bps 45mm / s

  Therefore, the upper limit setting unit 15 sets 270 mm / s as the upper limit if the detected baud rate is 57600 bps. If the detected baud rate is 38400 bps, the upper limit value is set to 180 mm / s. If the detected baud rate is 9600 bps, the upper limit value is set to 45 mm / s. If a page mode command and a graphic print command are detected in the print data, it is determined in step ST2 that determines the print mode that the print mode does not require reception of print data. The upper limit is set to the maximum printing speed of 220 mm / s (step ST4).

  When the upper limit value of the printing speed of the line thermal head 8 is set in the step ST3 or ST4 for setting the upper limit value, the drive control means 13 drives the line thermal head 8 at a printing speed equal to or lower than the set upper limit value. At the same time, the stepping motor 11 is controlled so that the recording paper 4 is conveyed at a conveying speed corresponding to the printing speed of the line thermal head 8 to perform printing (step ST5). When the detected baud rate is 57600 bps, the upper limit value is set to 270 mm / s. However, since the maximum printing speed inherent in the line printer is 220 mm / s, 220 mm / s is set as the upper limit value. Then, printing is performed.

  As described above, according to the line printer of this embodiment, when the baud rate detecting unit 14 detects a low baud rate, the upper limit setting unit 15 sets the upper limit of the printing speed of the line thermal head 8 to a low level (step ST3). The drive control unit 13 controls the printing speed of the line thermal head 8 so that the printing speed is equal to or lower than the set upper limit value, and also controls the conveyance speed of the recording paper 4 to perform printing (step ST5). As described above, when the baud rate is low and the print data transfer speed is low, the line thermal printer 1 itself slows down the print speed, so printing for one line of the line thermal head 8 is awaited to receive the print data. It is possible to avoid that printing is interrupted every time. Therefore, it is possible to keep the printing quality high by avoiding fluctuations in the feed amount of the recording paper 4 and disturbing the printing pitch, or changing the printing density and causing printing unevenness.

Further, according to the line thermal printer 1 of this embodiment, when a page mode command or a graphic print command is detected, printing can be performed at the maximum printing speed regardless of the baud rate set in the communication interface 2. (Steps ST2 and ST4).

  Furthermore, since the upper limit value storage unit 17 stores candidates for the upper limit value of the printing speed in a format associated with the baud rate, the process of setting the upper limit value of the printing speed by the upper limit value setting unit 15 is easy. . Further, when the upper limit value of the printing speed of the line thermal head 8 is changed depending on the application of the line thermal printer 1, it is only necessary to change the value stored in the upper limit value storage unit 17, so that the setting can be easily changed. is there.

  For example, the example upper limit value is the upper limit value that is set when the primary use is the issuance of an accounting statement that prints a list of purchased items and amounts in a fixed font. In the case of frequent use of coupons that include, the control command included in the print data transmitted from the host computer 30 increases, and the control unit 7 prints for each line from the print data. Since the processing speed for generating data decreases, the upper limit value corresponding to the baud rate is set about 10% lower than the illustrated value. In such a case, the printing speed of the line thermal head 8 can be controlled to an appropriate value only by rewriting the upper limit speed stored and held in the upper limit value storage unit 17.

  Although the print head of the line printer of this embodiment is a line type thermal head, the present invention can be applied to a line printer having a print head of another type. The communication interface of the present embodiment is an RS-232C serial interface, but the present invention can also be applied to a line printer having a communication interface other than the communication interface.

1 is a schematic configuration diagram of a line thermal printer to which the present invention is applied. It is a flowchart which shows the operation | movement which sets the upper limit of printing speed based on a baud rate.

Explanation of symbols

1. Line thermal printer 2. Communication interface 4. Recording paper 5. Dip switch 6. Receive buffer 7. Main control unit 8. Line thermal head 9. Print buffer 10. Latch circuit 11. Stepping motor, 12 platen roller, 13 drive control means, 14 baud rate detection means, 15 upper limit setting means, 16 print mode detection means, 17 upper limit storage section, 18 image storage section, 30 host Computer

Claims (11)

In a print control method of a line printer that prints print data received from the outside via a communication interface line by line by a line type print head,
The line printer detects the baud rate of the communication interface at the time of initialization after the drive power is turned on and / or at the start of reception of print data.
The line printer sets an upper limit value of the print speed of the line type print head based on the baud rate so that a print interruption state for waiting to receive print data does not occur every time one line is printed. A print control method for a line printer. In claim 1,
The line printer sets the upper limit of the print speed of the line type print head to a preset first upper limit speed, regardless of the baud rate, when printing in a print mode that does not require reception of print data. A print control method for a line printer. In claim 2,
As a baud rate of the communication interface, at least a first baud rate and a second baud rate lower than the first baud rate can be set.
In the case of the first baud rate, the upper limit value is set to a preset second upper limit speed,
In the case of the second baud rate, the upper limit value is set to a preset third upper limit speed,
The line control printing method, wherein the second upper limit speed is lower than the first upper limit speed, and the third upper limit speed is lower than the second printing speed. In claim 3,
The print mode that does not require waiting for reception of the print data includes a mode in which the print data received through the communication interface is stored in the print buffer up to the break of the print data and then printing is started. A print control method for a line printer. In any of claims 1 to 4,
A line printer print control method, wherein the line type print head is a line type thermal head. In a line printer capable of printing print data received from the outside via a communication interface on a recording medium line by line by a line type print head.
Baud rate detecting means for detecting the baud rate of the communication interface;
Upper limit setting means for setting an upper limit value of the printing speed of the line-type print head based on the detected baud rate so that a print interruption state for waiting to receive print data does not occur every time one line is printed;
Drive control means for driving the line-type print head at a printing speed equal to or lower than a set upper limit value, and carrying the printing by carrying the recording medium at a carrying speed corresponding to the printing speed;
A line printer comprising: In claim 6,
Print mode detection means for detecting whether or not the print mode does not require waiting for reception of print data;
The upper limit setting means sets the upper limit value of the print speed of the line type print head to a preset first upper limit speed regardless of the baud rate when it is detected that the print mode is set. A line printer characterized by that. In claim 7,
At least three types of the upper limit values are stored and held: the first upper limit speed, the second upper limit speed that is lower than the first upper limit speed, and the third upper limit speed that is lower than the second upper limit speed. An upper limit storage unit;
The communication interface can set the baud rate to at least a first baud rate and a second baud rate lower than the first baud rate.
The upper limit value setting means sets the upper limit value to the second upper limit speed in the case of the first baud rate, and sets the upper limit value to the third upper limit speed in the case of the second baud rate. Characteristic line printer. In claim 8,
A print buffer for expanding and storing the received print data into print data for each line;
The print mode that does not require reception of print data includes a mode in which printing is started after the print data received via the communication interface is stored in the print buffer up to the end of the print data. A line printer characterized by that. In claim 9,
The communication interface includes a dip switch for setting the baud rate,
The line printer according to claim 1, wherein the baud rate detecting means detects a baud rate from the state of the dip switch. In claim 10,
The line printer is characterized in that the line type print head is a line type thermal head.

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