JP2005186510A - Line type thermal printer and its divide driving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose a divide driving method of a line type thermal printer which can print a printing pattern consisting of repetitions of a character font and non-printing feeding, without a pitch disorder of printing dots accompanied at a leading part of the character font. <P>SOLUTION: In the line type thermal printer 1, in the case of printing the printing pattern in which rows of the character font and non-printing feeding are repeated, the non-printing feeding is carried out by fast forwarding (up to a time point t1). At the time of printing the row of the character font where a leading one dot line is a non-printing dot line without printing dots, a motor energization switching period of the leading one dot line (blank dot line) is made longer than a motor energization switching period at the fast forwarding time, and a motor speed is switched to a low speed (period of time T2). Accordingly, an actual feeding speed of a recording paper at the time of printing of a next dot line (period of time T3) can be nearly agreed with the motor speed, so that the pitch disorder of the printing dots can be prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention divides a line thermal head into one or a plurality of printing blocks based on the total number of printing dots for one dot line, and drives these printing blocks sequentially to perform printing for each dot line. The present invention relates to a divided drive method for a printer. More specifically, the present invention relates to a divisional driving method for a line-type thermal printer that can suppress disturbance in the print dot pitch of a character font when printing a character font and a print pattern in which no-print feed is repeated.

  In a line-type thermal printer, when energizing each heating element of the line thermal head and printing one dot line, the maximum power consumption increases, so it is necessary to install a large drive power supply. Since handy-type small thermal printers are equipped with small battery power supplies, the line thermal head is divided into multiple printing blocks to reduce the maximum power consumption. I have to. In this case, if all the printing blocks are always driven sequentially regardless of the total number of printing dots of one dot line, the overall printing speed is lowered.

  Therefore, when the total number of print dots in one dot line is large, all the print blocks are sequentially divided and driven, and when the total number of print dots is small, only one print block or a small number of print blocks are driven to increase the print speed. I try to increase it. In this case, since the feeding pitch of one dot line of the recording paper is constant, if the number of divisions increases, it is necessary to reduce the feeding speed of the recording paper accordingly. A stepping motor is generally used as the transport motor, and the step feed speed of the stepping motor is adjusted by increasing or decreasing the motor energization switching period as the number of divisions increases or decreases. A line-type thermal printer that performs such division driving is disclosed in, for example, the following Patent Documents 1 and 2.

Here, when printing a print pattern in which character font lines and non-print lines are repeated by the division drive method, in order to reduce throughput (issue time of one transaction), sending non-print lines is Fast forward is performed faster than the feed speed when printing a character font line. For example, in the case of a print pattern in which a 12 × 24 dot character font line is printed, an operation of printing a 12 × 24 dot character font line is repeated with a space between 6 dot lines (no print line). is there. In this case, the inter-line feed of 6 dot lines increases the speed of the stepping motor for conveying the recording paper, that is, shortens the motor energization switching period and fast-forwards the recording paper.
JP 2000-246943 A Japanese Patent Laid-Open No. 2002-19171

  However, in the case of a print pattern in which character font and non-print feed are repeated, the following problems occur when non-print feed is performed by fast feed. That is, the feeding speed of the recording paper that has been fast-forwarded during non-print feeding is suddenly switched to low speed when the next character font is printed. Even if the stepping motor speed is switched to a low speed in order to switch the feed speed to a low speed, the recording paper being transported cannot be immediately switched to a low speed due to inertia. A time lag occurs. As a result, the recording paper is still fast-forwarded when the head portion of the character font, particularly the first one-dot line is printed.

  Since the driving of the line thermal head is synchronized with the energization switching cycle of the stepping motor, when the stepping motor is switched to a low speed, the driving speed of the line thermal head is also switched to a low speed. As a result, at the time of printing each dot line at the beginning of the character font, the recording paper is still fast fed despite the slow driving speed of the line thermal head. For this reason, the pitch between the dot lines at the head of the character font is wider than the pitch between the other dot lines. As a result, pitch irregularities occur in the print dots at the beginning of the character font, and the print quality of the character font printed on the recording paper is lowered as a whole.

  Conventionally, in order to give priority to the improvement of the throughput of the line-type thermal printer, the deterioration of the print quality of the character font due to such fast-forwarding is ignored and the print quality is sacrificed.

  SUMMARY OF THE INVENTION An object of the present invention is to propose a line type thermal printer and its divided driving method capable of preventing the pitch irregularity of the print dots of the character font even if the non-print feed is performed by the fast feed.

  In order to solve the above-mentioned problem, in the divided drive method of the line type thermal printer of the present invention, paying attention to the fact that the first dot line of the character font is generally composed of spaces (blank dots), no-print feed Switch the feed speed for the first dot line of the character font later to slower than fast feed, and the actual feed speed of the recording medium when printing the second and subsequent dot lines from the beginning of the character font. Thus, it is possible to carry out at a speed corresponding to the speed of the stepping motor determined according to the above, thereby preventing the pitch irregularity of the print dots at the head portion of the character font.

  That is, according to the division driving method of the line type thermal printer of the present invention, the line thermal head is divided into one or a plurality of printing blocks based on the total number of printing dots for one dot line; Based on this, the motor energization switching period of the stepping motor for conveying the recording medium for one dot line is determined; the printing block is sequentially divided and driven on the recording paper conveyed by the stepping motor. When printing a line of a character font in which the first dot line is a non-print dot line with no print dots after a non-print feed of a predetermined number of dot lines, the non-print feed is The motor energization switching of the first dot line in the character font line is performed at a speed. The period, so that longer than the motor energization switching period of time of the non-printing feed.

  The line-type thermal printer of the present invention includes: a line thermal head; a stepping motor for transporting a recording medium via a printing position of the line thermal head; and a head energization pulse control for driving the line thermal head in a divided manner. A motor energization pulse control unit for driving and controlling the stepping motor; and dividing the line thermal head into one or a plurality of printing blocks based on the total number of printing dots for one dot line; Based on the number of divisions, a motor energization switching period of a stepping motor for conveying the recording medium for one dot line is determined, the printing block is sequentially divided and driven on the recording paper conveyed by the stepping motor. In order to print one dot line, the head An energization pulse control unit and a drive control unit that drives and controls the motor energization pulse control unit; the drive control unit is configured to mark the first dot line with no print dots after the non-print feed of a predetermined number of dot lines. The motor energization switching period is set such that when a character font line that is a character dot line is printed, the feed speed of the first dot line in the character font line is slower than the non-print feed. It is characterized by switching.

  In the line type thermal printer of the present invention, when printing a print pattern in which character font lines and non-print feed are repeated, throughput can be increased by performing non-print feed by fast feed. Also, when printing a character font after fast-forwarding, the energization switching cycle of the stepping motor for sending one dot line, which is the leading blank dot, is set longer than the energization switching cycle during non-print feeding. . That is, the feed speed for the first dot line of the character font is switched to a lower speed than the feed speed at the time of non-print feed. In this way, the stepping motor energization switching cycle is lengthened in spite of blank dots, and the recording medium feed speed is switched to a low speed in advance, so that the stepping determined by the number of divisions at the time of the next one-dot line printing is performed. The recording medium can be conveyed at a speed corresponding to the motor speed (energization switching cycle). Therefore, according to the present invention, the print quality of the character font that has been sacrificed to improve the throughput can be maintained in a good state.

  Embodiments of a line type thermal printer to which the present invention is applied will be described below with reference to the drawings.

  FIG. 1 is a schematic block diagram showing the main part of the line type thermal printer of this example. As shown in this figure, a line-type thermal printer 1 includes a line thermal head 2, a platen roller 3 that conveys recording paper (not shown) via the printing position of the line thermal head 2, and a platen roller 3. And a printer control device 10 for driving and controlling the line thermal head 2 and the stepping motor 4.

  The printer control apparatus 10 is mainly configured of a microcomputer, and includes a drive control unit 20 including a CPU 11, a ROM 12 that stores various control programs, and a RAM 13 that is used as a work area. In addition, a head energization pulse controller 14 that drives the line thermal head 2 and a motor energization pulse controller 15 that drives the stepping motor 4 are provided. Print data is supplied to the printer control device 10 from the host device (not shown) via the data input unit 16. Under the control of the CPU 11, the stepping motor 4 is driven via the motor energization pulse control unit 15, and the line thermal head 2 is driven via the head energization pulse control unit 14.

  The line thermal head 2 has a configuration in which a plurality of heat generating elements, for example, heat generating elements for 432 dots, are arranged in a line, and are divided and driven for each printing block having a maximum of 128 dots, for example. In this case, when the total number of print dots for one dot line is 128 dots or less, all the print dots can be printed simultaneously, so the time required for printing one dot line (when the number of divisions is 1) is one. It is only necessary to apply a single period of energization pulse to one print block. Accordingly, since the printing time for one dot line can be shortened, the energization switching period for driving the stepping motor for feeding one dot line is also shortened (the driving speed is increased). When the total number of printing dots exceeds 128 dots, printing for one dot line is performed with the minimum number of divisions within the range of 2 to 4 divisions. For example, in the case of driving in two divisions (when the number of divisions is 2), in order to drive two printing blocks, it is necessary to sequentially apply energization pulses of a fixed period, so that a single printing block The printing time for one dot line is doubled as compared with the case of driving. Therefore, the energization switching period of the stepping motor for feeding one dot line is also doubled. That is, the driving speed is reduced to ½.

  Next, with reference to FIGS. 2 and 3, an operation in the case of printing a print pattern in which character font lines and non-print feed are repeated will be described. FIG. 2 is an explanatory diagram showing an example of a character font, and FIG. 3 is a timing chart showing a printing operation.

  First, as shown in FIG. 2, the character fonts F1, F2, F3... Are composed of, for example, 12 × 24 dots, and the leading one dot line L1 is a blank dot. In the printing operation of the printing pattern P in which the character font line R1 and the non-printing feed R2 are repeated, the non-printing feed R2 is performed by fast-forwarding. In the printing of the character font line R1, the total number of print dots of each dot line is obtained. The line thermal head 2 is divided and driven with the number of divisions calculated based on the division number.

  FIG. 3A is a graph showing the recording paper feed distance. A solid line A shows an ideal recording paper feed distance, and a broken line B shows an actual recording paper feed distance. 3B is a signal waveform diagram showing a head energization strobe pulse signal supplied from the head energization pulse control unit 14 to the line thermal head 2, and each print block (No. 1) of the line thermal head 2 divided into four. To No. 4), a head energization strobe pulse signal is supplied. FIG. 3C is a signal waveform diagram showing an energization pulse signal for driving the motor supplied from the motor energization pulse control unit 15 to the stepping motor 4.

  3, the stepping motor 4 is stepped at a speed corresponding to the energization switching periods T1, T2, T3, T4... By the energization pulses of each phase, and the recording paper is fed at a feed pitch for one dot line, for example, 0. It is transported at a pitch of 125 mm. The energization switching period T1 in the period up to the time point t1, which is the non-print feeding period, is the shortest, for example, 2 ms, and the stepping motor 4 is driven at a high speed to rapidly feed the recording paper.

  Next, in the printing operation of the line of the character font after the time point t1, the leading one line dot is a blank dot (see FIG. 2), and conventionally the stepping motor 4 is driven at the same speed as the fast forward speed. However, in this example, blank dots are fed at a low speed that is slower than the driving speed during fast-forwarding. That is, the energization switching cycle T2 of the stepping motor 4 is switched to a cycle longer than the energization switching cycle T1 at the time of the fast forward, for example, 5 ms.

  Thereafter, the printing operation of the first dot line of the second line from the beginning of the line of the character font is started from time t3. In this example, one pixel formed on the recording paper is constituted by 2-dot printing, and at the time t3 when the stepping motor 4 is switched to energization, an energization pulse for printing the first half dot for forming one pixel is applied, and the next energization is performed. At the switching time t4, an energization pulse for printing the latter half dot for forming one pixel is applied. For this reason, in the printing period T3 of one dot line, the head energization pulse having the same cycle is applied twice to the same printing block of the line thermal head 2.

  In the example of FIG. 3, in the period T4, the number of divisions of the line thermal head 2 is “4”, and all four printing blocks (No. 1 to No. 4) are driven to be printed for one dot line. In the periods T4 and T5, the number of divisions is “2”, and the two print blocks (No. 1 and No. 2) are driven to be divided to perform printing for one dot line. For example, the period in which the number of divisions is “1” is 2 ms, the periods T5 and T6 in which the number of divisions is “2” is 4 ms, which is twice that, and the period T3 in which the number of divided drives is “4” is four times that in the period T3. 8 ms.

  As described above, in the line type thermal printer 1 of this example, in the case of a print pattern in which character font lines and non-print feed are repeated, the feed speed of the first line dot (blank dot) of the character font is not printed. The speed is temporarily switched to a speed lower than the speed at the time of feeding (period T2 in FIG. 3). As the driving speed of the stepping motor 4 is switched, the actual recording paper feed speed follows a predetermined time lag. In this example, after the non-print feed (fast feed), the feed speed is once switched to a low speed, and then the division number of the line thermal head 2 is obtained based on the total number of print dots of one dot line, and based on this division number, Printing for each dot line is performed by division driving (after time t3 in FIG. 3).

  If the feed speed of one line dot (blank dot) at the beginning of the character font is set to the same speed as that in the fast feed as in the prior art, it corresponds to one line dot between time t1 and time t2 after 2 ms in FIG. At time t2, printing for one dot line of the second line from the beginning of the character font is started by four-division driving, and the energization switching cycle of the stepping motor 4 becomes four times longer than that at the time of fast-forwarding. Speed drops to ¼. However, the actual recording paper is conveyed at a fast-forward speed for a while due to inertia, and is switched to a low speed after a predetermined time lag (see the one-dot chain line C in FIG. 3A). Therefore, the pitch of the first half dot and the second half dot forming one pixel in the printing of the second one dot line from the head of the character font is disturbed.

  In contrast, in this example, since the first dot line (blank dot) of the character font is sent at a low speed, the actual conveyance speed of the recording paper is also switched to a low speed when printing is started. ing. Therefore, the recording paper can be conveyed at an ideal conveyance state, that is, at a speed corresponding to the driving speed of the stepping motor 4 with almost no time lag, and the pitch fluctuation of the printing dot at the head portion of the character font can be prevented. Can be prevented. Therefore, according to the line type thermal printer 1 of this example, it is possible to print a print pattern composed of repeated character fonts and non-print feeds with a good print quality without substantially reducing the throughput.

1 is a schematic block diagram of a line type thermal printer to which the present invention is applied. It is explanatory drawing which shows the example of a character font. 2 is a timing chart of a printing operation of the line type thermal printer of FIG. 1.

Explanation of symbols

1 line type thermal printer, 2 line thermal head, 3 platen roller, 4 stepping motor, 10 printer control device, 11 CPU, 12 ROM, 13 RAM, 14 head energization pulse control unit, 15 motor energization pulse control unit, 20 drive control Part

Claims (2)

Based on the total number of print dots for one dot line, the line thermal head is divided into one or more print blocks,
Based on the number of divisions of the line thermal head, the motor energization switching period of the stepping motor for conveying the recording medium for one dot line is determined,
The print block is sequentially divided and driven, and the recording paper conveyed by the stepping motor is printed on the one-dot line.
When printing a line of a character font in which the first dot line is a non-printing dot line with no print dots after a non-print feed of a predetermined number of dot lines, the non-print feed is performed at a predetermined speed, and the character A divisional driving method for a line-type thermal printer, wherein the motor energization switching cycle of the first dot line in a font line is longer than the motor energization switching cycle during the non-print feeding. Line thermal head,
A stepping motor for transporting the recording medium via the print position of the line thermal head;
A head energization pulse control section for dividing and driving the line thermal head;
A motor energization pulse controller for driving and controlling the stepping motor;
Stepping for dividing the line thermal head into one or a plurality of printing blocks based on the total number of printing dots for one dot line, and conveying the recording medium for one dot line based on the number of divisions of the line thermal head. The head energization pulse control unit is configured to determine a motor energization switching period of the motor, sequentially divide and drive the print blocks, and perform printing for the one dot line on the recording paper conveyed by the stepping motor. And a drive control unit that drives and controls the motor energization pulse control unit,
The drive control unit prints a character font line in which the first dot line is a non-printed dot line with no print dots after a predetermined number of non-print feeds. A line-type thermal printer that switches the motor energization switching period so that the feed speed of the first dot line is slower than the non-print feed.

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