WO2007135785A1

WO2007135785A1 - Thermal printer and driving method of thermal printer

Info

Publication number: WO2007135785A1
Application number: PCT/JP2007/050894
Authority: WO
Inventors: Masaji Iwata
Original assignee: Citizen Holdings Co., Ltd.
Priority date: 2006-05-19
Filing date: 2007-01-22
Publication date: 2007-11-29
Also published as: JP2007307808A

Abstract

A thermal printer, comprising a sheet feed means for conveying a thermal sheet, and a thermal head having a plurality of heating elements arranged linearly on a line intersecting the sheet feed direction perpendicularly, is further provided with a means for selecting heating elements to be energized, wherein the selection means switches between a plurality of dispersion patterns for selecting heating elements to be energized from among the plurality of heating elements, and selects heating elements to be energized by ANDing a pattern with a line of print data sequentially. Heating elements energized and heated on one line are dispersed using a dispersion pattern and biased temperature distribution due to cooling after heating is corrected thus suppressing occurrence of sticking due to biased temperature distribution. Consequently, biased temperature distribution is corredted in the entire head, and sticking and degradation in print quality are suppressed.

Description

Specification

Thermal printer and thermal printer driving method

Technical field

The present invention relates to a thermal printer that performs thermal recording with a thermal line head and a driving method, and more particularly to prevention of sticking.

Background art

[0002] Thermal printers that record images and characters on thermal paper using a thermal line head configured by linearly arranging a plurality of heating elements are known. In this thermal printer, when all the heating elements in the line are energized and driven simultaneously, a large drive power is required, and the power supply device is also enlarged, so the thermal line head is divided into a plurality of blocks. Drive control in units of blocks is employed (see, for example, Patent Document 1).

[0003] In such a thermal printer, the ratio of the heating elements that are driven to generate heat among all the heating elements of the thermal line head is high! (High !, printing rate) or when the temperature is low. It is known that when driving in an environment, a phenomenon called stateking occurs! In this sticking, when a thermal paper made by laminating a thermal layer and an overcoat layer on a base paper is heated with a heating element, the molten overcoat layer solidifies, so that the surface of the heating element becomes a thermal paper. This sticking phenomenon, when this staging occurs, makes it difficult to accurately feed the thermal paper, causing pitch irregularities and reducing print quality.

FIG. 19 and FIG. 20 are explanatory diagrams and flowcharts for explaining a printing operation by a conventional thermal printer. A single line is energized by sequentially dividing the heating elements of multiple blocks. Fig. 19 shows a state where three blocks are driven by three energizations, and Fig. 20 shows a state where six blocks are energized sequentially. In Fig. 20, all blocks are printed sequentially in a time-division manner within the period Tc of one step operation of the stepping motor. At this time, since the head of block 1 is heated and printing is completed, it takes a relatively long time tl from the end of printing by the head of block 6 to the next step operation by the motor. Heat sensitivity melted by heating the heads of Block 1 and Block 2 to Block 5 The paper overcoat layer cools and solidifies, and staging occurs.

[0005] Therefore, in order to prevent such sticking, it has been proposed to melt the overcoat layer by applying a short pulse to the heads of all blocks again after the energization of all blocks is completed. .

[0006] In addition, when a short pulse is reapplied to the heads of all the blocks described above, there is a problem in that sticking occurs if the application interval of the short pulse to each block is long. The heating element of the thermal line head is divided into a plurality of blocks, and a group is formed by a plurality of blocks. This group is driven sequentially, and the paper is fed by fewer than 1 dot after each drive. It has been proposed to prevent this (see Patent Document 2).

FIGS. 21 and 22 are a flow chart and an operation explanatory diagram for explaining an operation example in which sequential driving of groups and paper feeding less than one dot after each driving are performed. Fig. 21 (a) shows an example in which each block is driven alternately in a group consisting of two blocks, and paper feed (ul, u2, u3, u4, ...) is performed after the group is driven. Fig. 21 (b) shows an example in which two blocks in a group are driven simultaneously, and paper feed (ul l, ul2, ul3, ul4, ...;) is performed after group driving. Here, an example is shown in which six blocks are grouped into three groups.

[0008] When driving and paper feeding in units of groups are repeated, as shown in FIG. 22, in the printing for the whole line, the end portion for starting the scanning and the end portion for ending the scanning In between, there is a step that adds the amount of movement of each paper feed.

Patent Document 1: Japanese Patent Laid-Open No. 03-266657

Patent Document 2: JP 2001-63124 A

Disclosure of the invention

Problems to be solved by the invention

[0009] When energization is performed on a block-by-block basis as in the prior art, in the scanning direction of the line head, the first block is printed from the end of printing in that block until the last block is printed. In the meantime, it is in contact with the thermal paper, and when the printing of the last block is completed, the temperature drops and sticking is likely to occur.

[0010] In addition, a configuration in which energization and paper feeding are repeated for each block in order to prevent occurrence of staging However, since current is applied in units of blocks, the temperature distribution is biased when viewed from the whole head. Therefore, it is necessary to shorten the block length in order to prevent sticking satisfactorily. However, if the block length is shortened in this way, the number of paper feeds increases, and the end of scanning and the scanning end. There is a problem that the level difference between the ends becomes large.

[0011] Therefore, the present invention aims to solve the above-described problems and suppress staging, and thereby suppress a decrease in print quality.

It is another object of the present invention to reduce the temperature distribution bias in the entire head.

Means for solving the problem

[0013] The present invention suppresses the deviation of the temperature distribution of the head, in particular, the deviation of the temperature drop portion after heating in the head, by energizing the heating element dispersed throughout the head of the thermal printer. Suppress the occurrence of stateking. In the following, it is assumed that the thermal printer performs the printing operation based on the print data sent by the host. Here, the print data includes not only character data but also image data, and includes both character data and image data.

The present invention includes a thermal printer driving method as a first aspect, and a thermal printer as a second aspect.

[0015] The first aspect of the present invention is the driving of a thermal printer that performs thermal recording on thermal paper that is fed by a thermal head that linearly arranges a plurality of heating elements on a line that is orthogonal to the paper feeding direction. This method has a plurality of dispersion patterns for selecting a heating element to be energized from among a plurality of heating elements, and energizes the heating element in one line by taking the logical product of this dispersion pattern and one line of print data. Select the heating element to be used. The selected heating element is selected by each dispersion pattern from the dots printed on one line, and a part of the print data is printed by energizing the heating element. With only one distributed pattern, only a part of one line data is printed. However, by combining printing with a plurality of distributed patterns, all of one line data is printed.

[0016] Further, the second aspect of the thermal printer of the present invention includes a paper feeding means for conveying thermal paper, a thermal head that linearly arranges a plurality of heating elements on a line orthogonal to the paper feeding direction, and Is a thermal printer. The thermal printer selects the heating element to be energized A selection unit is provided, and the selection unit switches between a plurality of dispersion patterns for selecting a heating element to be energized from among the plurality of heating elements, and sequentially generates a logical product with one line of print data to generate energization. Select the body.

[0017] By using the dispersion pattern, it is possible to disperse the heating elements that are energized and heated on one line, and to reduce the temperature distribution bias due to cooling after heating. Thereby, it is possible to suppress the occurrence of sticking due to the uneven temperature distribution.

[0018] The dispersion pattern can be in a plurality of modes. The first aspect of the distribution pattern can be applied to a form in which the thermal head is divided into a plurality of blocks. The dispersion pattern of this aspect is a pattern for selecting a heating element to be energized from among the heating elements included in each block. Each distribution pattern selects one or more heating elements in the block. These dispersion patterns have a plurality of patterns with different heating elements to be selected, and a total dispersion pattern can be configured by combining these dispersion patterns. By using this total dispersion pattern, all the heating elements on one line of the thermal head are selected only once. Therefore, by using each dispersion pattern, it is possible to print while dispersing the print data.

[0019] In this form of division into blocks, the dispersion pattern is selected as a heating element for energizing one or more heating elements included in each block. In the case of a dispersion pattern in which one heating element is selected in a block having n heating elements, all the heating elements can be selected by the n dispersion patterns. In addition, in a block having n heating elements, in the case of a distributed pattern in which m heating elements are selected, there are C distribution patterns that are the number of combinations in which n forces m are selected without duplication.

n m

All the heating elements can be selected. In addition, a dispersion pattern for selecting a plurality of heating elements can be selected as a heating element for energizing the same number of heating elements in each block.

[0020] When a plurality of dispersion patterns are applied to print data, each dispersion pattern is switched and applied. One aspect of applying the plurality of dispersion patterns is to record the dispersion pattern in advance and switch the dispersion pattern to be used by sequentially reading the recorded plurality of dispersion pattern forces. In another aspect, a plurality of dispersion patterns are The print data of one line is sequentially formed avoiding duplication, and the dispersion pattern is switched by using the dispersion pattern that is formed sequentially.

[0021] The recording unit records a plurality of dispersion patterns. The dispersion pattern is switched by sequentially circulating and reading out a plurality of dispersion patterns from the recording means. The dispersion pattern forming means sequentially forms a plurality of dispersion patterns. The dispersion pattern is switched by sequentially forming a plurality of dispersion patterns from the dispersion pattern forming means.

[0022] In addition to conveying the thermal paper after each energization, the paper feeding means may transport the thermal paper after printing of one line of print data is completed.

The invention's effect

[0023] According to the thermal printer and the thermal printer driving method of the present invention, sticking can be suppressed, and deterioration in print quality can be suppressed. In addition, the temperature distribution in the entire head can be reduced.

Brief Description of Drawings

FIG. 1 is a diagram for explaining a schematic configuration of a thermal printer of the present invention.

FIG. 2 is a schematic diagram for explaining the formation of a print pattern using the dispersion pattern of the invention.

FIG. 3 is a schematic diagram for explaining a more detailed configuration example of the thermal printer of the present invention.

FIG. 4 is a diagram illustrating data stored in ROM and RAM included in the control unit of the present invention.

FIG. 5 is a flowchart for explaining the operation of the thermal printer.

FIG. 6 is a time chart for explaining the operation of the thermal printer.

FIG. 7 is an explanatory diagram for explaining the operation of the gate array.

FIG. 8 is a diagram showing an example of a dispersion pattern in which printing is performed by selecting one dot in a block.

FIG. 9 is a diagram showing an example of a dispersion pattern for printing by selecting two dots in a block.

FIG. 10 is a diagram showing an energized state by a dispersion pattern. FIG. 11 is a flowchart for explaining a switching operation between distributed energization and block energization.

FIG. 12 is a flowchart for explaining a switching operation between distributed energization and block energization.

13] This is a diagram for explaining the state of printing by switching between block energization and distributed energization.

FIG. 14 is a diagram showing an example of forming a dispersion pattern for each dot line data of each line.

FIG. 15 is a diagram illustrating data stored in ROM and RAM included in the control unit of the present invention.

圆 16] An explanatory diagram for explaining another operation of the gate array.

FIG. 17 is a diagram showing an example of a dispersion pattern in which printing is selected in a block.

FIG. 18 is a flowchart for explaining a mode in which printing is performed by a formed dispersion pattern.

FIG. 19 is an explanatory diagram for explaining a printing operation by a conventional thermal printer.

FIG. 20 is a flowchart for explaining a printing operation by a conventional thermal printer.

21] This is a flowchart for explaining an operation example in which sequential driving of groups and paper feeding less than one dot after each driving are performed.

[22] This is a flowchart for explaining an operation example in which sequential driving of groups and paper feeding less than one dot after each driving are performed.

Explanation of symbols

1 Thermal printer

2 CPU

3 Thermal line head

4 Dispersion pattern

10 Host computer

20 Control unit

21 ROM 22 RAM

23 Gate array

24 motor dryer

25, 26, 27 connectors

28 AZD Converter

30 Printer mechanism

31 1st buffer

32 Second buffer

33 Head

34 Motor

35 Head sensor

36 Media sensor

37 Temperature sensor

BEST MODE FOR CARRYING OUT THE INVENTION

First, an embodiment of the thermal printer of the present invention will be described.

FIG. 1 is a diagram for explaining a schematic configuration of a thermal printer of the present invention. In FIG. 1, the thermal printer 1 generates a plurality of heat generations on a line perpendicular to the paper feed direction with respect to thermal paper (not shown) fed by the paper feed motor 34 by the processing of the CPU 2. Thermal recording is performed by driving a thermal line head 3 in which a body (not shown) is linearly arranged.

The CPU 2 inputs print data from the host 10 and converts it into a signal form that can be processed by the thermal line head 3 based on the print data and the dispersion pattern 4. CPU2 sends the converted print data signal (DATA) to thermal line head 3 in the cycle of the clock signal (CLOCK), holds the print data signal (DATA) by the latch signal (LATCH), and then strobe signal (STB1 to STB3,...) Etc. perform printing operation for each block. Further, the CPU 2 drives the paper feed motor 34 by the driver 24.

The thermal printer 1 of the present invention forms a print pattern using the dispersion pattern 4 for the print data input from the CPU 2. Using a dispersion pattern during printing The printing dots in the printing pattern are dispersed so as not to be biased, thereby preventing the temperature distribution from being biased.

FIG. 2 is a schematic diagram for explaining the formation of a print pattern using the dispersion pattern of the present invention. FIG. 2 shows an example in which four dispersion patterns are used. When four distribution patterns are used, one line of print data is converted into four print patterns by four distribution patterns. Among the plurality of heat generating elements arranged on the thermal line head, energization is performed on the heat generating elements corresponding to each print pattern to perform dot printing. Here, four printing patterns with four dispersion patterns are provided, so printing is performed with one line of print data by four energizations from the first energization to the fourth energization.

[0031] After the printing of one line is completed, the next one line of print data is energized four times from the first energization to the fourth energization in the same manner as the previous printing process. Print one line of print data.

[0032] Here, in addition to a mode in which paper feeding is performed during energization of each print pattern, a mode in which paper feeding is not performed may be employed. According to the mode in which the paper is fed during energization of each printing pattern, the previous energized location and the next energized location are different line positions on the same line by the moving pitch, so that the sticking can be reduced. it can. By setting the movement pitch to 1Z4 for one line, misalignment due to movement of the print location is reduced.

[0033] Further, according to the aspect in which paper feeding is not performed during energization of each print pattern, the previous energization location and the next energization location are the same line position on one line, but by using the dispersion pattern, Since the vicinity is heated in each energization, the degree of cooling after heating can be suppressed, and sticking can be reduced.

Next, a more detailed configuration example of the thermal printer of the present invention will be described with reference to FIG. In FIG. 3, the thermal printer 1 includes a control unit 20 including a CPU 2 and a printer mechanism 30 including a line head unit 33. Here, print data is input from the host computer 10 and converted into a print pattern that can be printed by the line head unit 33 by the control unit 20, and printed by the line head unit 33 of the printer mechanism 30 based on this print pattern. Example to Show.

The control unit 20 inputs print data from the host computer 10 connected via the connector 25. The control unit 20 is connected to ROM 21, RAM 22, gate array 23, motor driver 24, and the like. The ROM 21 stores a print control program for controlling the print operation, distributed patterns, etc., and the RAM 22 is obtained by converting the print data (first print data) input from the host computer 10 or this print data. Stores dot line data (second print data), etc. The gate array 23 also sends distributed data to the printer mechanism 30.

[0036] The control unit 20 sends the distributed data from the gate array 23 to the printer mechanism 30 through the connector 26, the converted print pattern data C, and the clock signal B for sending the data C, Send latch signal A to printer mechanism 30.

The control unit 20 has a motor driver 24 and drives and controls the paper feed motor 34 of the printer mechanism 30 via the connector 27. The connector 27 inputs sensor signals from the sensors such as the head sensor 35, the paper sensor 36, and the temperature sensor 37 included in the printer mechanism 30 and sends them to the CPU 2. The head sensor 35 detects the pressure contact or separation of the thermal line head 3 from the thermal paper, the paper sensor 36 detects the transport position or presence of the paper, and the temperature sensor 37 detects the temperature of the line head 33. To detect.

The control unit 20 includes an AZD conversion unit 28, and converts an analog signal (not shown) received from the printer mechanism 30 via the connector 26 into a digital signal.

FIG. 4 is a diagram illustrating data stored in the ROM 21 and RAM 22 included in the control unit 20 of the present invention.

In FIG. 4, the ROM 21 stores a print control program, a character generator (font data), distributed data, and the like. The print control program is a control program for causing the CPU to execute control related to the printing operation. For example, the control of data exchange performed through each connector 25, 26, 27, the print data fetched from the host computer 10 Various controls such as control to convert (first print data) into dot line data (second print data) for driving the dot line head 33 and control of the motor driver 24 are performed. The character generator is font data for forming a print on the dot line head 33.

[0041] Further, the distributed data is a distributed pattern in which dot line data is distributed on a line and printed. Pattern data for forming a pattern. Here, the pre-formed pattern data is stored in the ROM 21, and sequentially read out and used. The distributed data may be stored in the ROM 21 or may be formed for each process and temporarily stored in the RAM 22. The configuration for forming and using this dispersion pattern will be described later.

The RAM 22 stores print data (first print data) input from the host computer 10 and dot line data (second print data) obtained by converting the print data. The first print data includes character code data and image data representing print contents, print control code data, etc., and the second print data is dot line data and strobe data developed on each line. Read and analyze the first print data written in RAM22, then write it in RAM22. The written second print data is sequentially read out by the CPU 2 and sent to the first buffer 31 of the printer mechanism 30 via the gate array 23.

In FIG. 3, the printer mechanism 30 includes a first buffer 31, a second buffer 32, and a line head unit 33, a paper feed motor 34 for feeding paper, a head sensor 35, a paper sensor 36, and a paper sensor 36. Each paper sensor such as temperature sensor 37 is provided. The first buffer 31, the second buffer 32, and the line head unit 33 constitute a thermal line head 3.

The CPU 2 reads the dot line data stored in the RAM 22 for each line and sends it from the connector 26 to the first buffer 31. The first buffer 31 sequentially takes in the dot line data for one line based on the clock signal. In FIG. 3, the dot line data is indicated by data C, and the clock signal is indicated by clock B. Also, the second buffer 32 transfers the dot line data stored in the first buffer 31 based on the latch signal A from the control unit 20. The second buffer 32 is a temporary memory that holds dot line data for driving the line head unit 33. The dot line data held in the first buffer 31 is transferred to the second buffer 32. The present invention performs this data transfer in a distributed manner without simultaneously performing all data. In this data transfer from the first buffer 31 to the second buffer 32, the dot line data held in the first buffer 31 is selected by the distributed data sent from the ROM 21 or RAM 22 via the gate array 23. To do. The line head unit 33 performs printing using the dot line data transferred to the second buffer. [0045] As described above, only the dot line data selected by the distributed data is transferred to the second buffer 32, and only the transferred dot line data is printed. Dot line data that is not transferred remains in the first buffer, and printing will not be completed if it remains as it is. Using a plurality of different distributed data that covers all dots, each of these distributed data is used in sequence to perform data transfer and printing. All dot line data can be printed by repeating.

[0046] Thus, by printing dot line data by a plurality of operations using the distributed data, the power supplied to the line head unit can be reduced, and the heating elements arranged in a line shape On the other hand, by dispersing the heating elements to be driven, it is possible to prevent the head portion from being locally cooled due to the increase of the driving interval, and to suppress the occurrence of the sticking.

[0047] It should be noted that the heating elements actually arranged in a line shape are not determined only by the dispersion pattern determined by the dispersion data. The heat distribution is not necessarily determined by the dispersion pattern because it is an overlap part obtained by the logical product of the above, but the dispersion power of the print data is statistically avoided in the direction of local cooling of the head part. .

FIG. 3 shows an example in which the line head unit 33 is divided into a plurality of blocks (block 1, block 2,..., Block n). In the case of the line head section 33 having a plurality of blocks, a force capable of forming a dispersion pattern in each block is a combination of a plurality of blocks that do not necessarily need to form a dispersion pattern in units of blocks. A dispersion pattern may be formed as a unit, or a dispersion pattern may be formed for dots (heating elements) provided in a line head unit that does not depend on blocks. In the case where a dispersion pattern is formed using a combination of a plurality of blocks as a unit, the plurality of blocks are not limited to adjacent blocks but may be dispersed.

Next, the operation of the thermal printer of the present invention will be described with reference to FIGS. 1 and 5 to 7. 5 is a flowchart for explaining the operation of the thermal printer, FIG. 6 is a time chart for explaining the operation of the thermal printer, and FIG. 7 is an explanatory diagram for explaining the operation of the gate array. It is. Print data is transmitted from the host computer 10 to the control unit 20 of the thermal printer 1. Here, the print data is data for printing by a thermal printer, and includes not only character data but also image data. The terminology used for printing shall include images as well as characters (Sl). The CPU 2 of the control unit 20 stores the print data input via the connector 25 in the RAM 22 as the first print data (S2).

[0051] CPU 2 reads and analyzes the character code data and print control code data included in the first print data from RAM 22, and forms dot line data and strobe data for printing on the paper by the line head. (S3), the formed second print data is stored in RAM22. Since this data analysis is a generally known process, a description thereof is omitted (S4).

[0052] CPU 2 reads dot line data (data C in Fig. 6) (shown in Fig. 6 (a)) from RAM 22 for one line and passes it through connector 26 to clock B (shown in Fig. 6 (b)). Synchronously, sequentially send to the first buffer 31 and store (S5, S6). For the dot line data latched in the first buffer 31 by the latch signal (shown in Fig. 6 (c)), only the data determined by the distributed data sent from the gate array 23 is selected and transferred to the second buffer 32. (S7).

FIG. 7 shows the operation of the gate array and the selective transfer operation of the dot line data from the first buffer 31 to the second buffer 32 based on the distributed data. Fig. 7 shows an example of setting distributed data in units of blocks, and shows an example of a distributed pattern that determines driving for 4 dots as distributed data.

The CPU 2 selects distributed data (S8), fetches the selected distributed data (here, data for 4 bits) from the ROM 21, and sends it to the gate array 23 (S9). The gate array 23 sends the distributed data (distributed data (d) to (g) in FIG. 6) to the buffer in synchronization with the latch signal A ((h) in FIG. 6). Here, an example of [1000] distributed data is shown.

The second buffer 32 takes in the dot line data selected based on the distributed data sent from the first buffer 31. Here, of the data stored in the first buffer 31, only the bit portion data determined by the distributed data is transferred to the second buffer 32. In FIG. 7, in each block, only the dot line data of the first bit determined by [1000] distributed data is transferred to the second buffer 32, and the dot line data of the second to fourth bits are The data is not transferred to the second buffer 32, and no data is maintained. Here, the second notifier 32 is cleared after each printing operation and returns to the initial state.

FIG. 7 shows an example in which the dot line data stored in the first buffer has data (indicated by 參) that enables printing in the bit portion corresponding to all dots. Data (indicated by 參) is stored in the first bit portion (left end in the figure) of each of the 32 blocks. If the dot line data in the first bit portion is data that disables printing, the initial state is substantially the same as the bit portion that was selected in the distributed data (S10). The data stored in the second buffer 32 is sent to the line head unit 33 (Sl l). The line head unit 33 performs dot printing in each block. Printing with one distributed data prints only a part of all dot line data, and printing for one line is performed by performing all printing with the remaining distributed data. Figure 6 (i) corresponds to printing with the first distributed data.

[0057] As shown in FIG. 7, when four pieces of distributed data are provided, the printing of one line is completed by repeating the steps S9 to S12 while changing the distributed data in the step S8. Fig. 6 (j) to Fig. 6 (1) correspond to printing with the second to fourth distributed data (S12).

Here, the CPU 2 more effectively suppresses the sticking by driving the paper feed motor 34 by the motor driver 24 and feeding the paper every time printing by each distributed data is completed. ((M) in Fig. 6). The feed amount of this paper feed can be obtained by dividing the feed amount for one line by the number of times of distributed processing, so that when a plurality of printing operations by dispersion are completed, it is within the line width. In step S13, one line is printed.

[0059] When printing of one line is completed (S14), the next dot line data is taken into the first buffer, and the next line is printed by repeating steps S6 to S14 (S15).

) o

[0060] Various patterns can be used as the dispersion pattern. Fig. 8 shows an example of a distributed pattern in which one dot is selected in the block, and Fig. 9 shows an example of a distributed pattern in which two dots are selected in the block. [0061] The example shown in FIG. 8 is an example of a dispersion pattern when four dots are one block, and one dot in this block is selected, and shows the same example as the example shown in FIG. . Here, four dispersion patterns are included to select one dot from four dots. The dispersion pattern shown in FIG. 8 includes four dispersion patterns [1000], [0100], [0010], and [0001]. In Figure 8, the first distribution pattern [1000] selects the first bit in the block for printing, and the second distribution pattern [0100] selects the second bit in the block. To print. Similarly, the third distribution pattern [0010] selects and prints the third bit in the block, and the fourth distribution pattern [0001] selects and prints the fourth bit in the block. I do.

[0062] When paper is fed between prints using each of the dispersion patterns, one line is printed in one cycle from tl to t4. The next line is printed in the next t5 to t8 (showing t5 and t6 in Fig. 8). Here, an example in which the dot line data is data to be printed for each dot is shown.

[0063] FIG. 10 (a) shows an energized state according to the dispersion pattern of FIG. Fig. 10 (b) shows the energization state with another dispersion pattern for selecting one dot. The dispersion pattern example in Fig. 10 (a) is an example in which dots are selected in order, and the dispersion pattern example in Fig. 10 (b) is an example in which dots are selected in any order.

[0064] According to the dispersion pattern in Fig. 10 (a), a straight line is printed by repeating diagonal lines in units of blocks. In addition, according to the distribution pattern in Fig. 10 (b), one straight line is distributed and printed.

[0065] The example shown in Fig. 9 is an example of a dispersion pattern when four dots are one block and two dots in this block are selected. Here, 2 dispersion patterns are included to select 1 dot from 4 dots. The dispersion pattern shown in Fig. 9 includes two dispersion patterns [1010] and [0101]. In Figure 9, the first distribution pattern [1010] selects the first and third bits in the block for printing, and the second distribution pattern [0101] displays the second bit in the block. Select the 4th bit and print.

[0066] When paper is fed between prints using each dispersion pattern, one line is printed in one cycle of tl and t2, and the next line is printed in one cycle of t3 and t4. Printing is done The Here, the dot line data is an example of printing data for each dot. Fig. 10 (c) shows the energization state according to the dispersion pattern of Fig. 9. Fig. 10 (d) shows the energization state with another dispersion pattern that selects 2 dots.

[0067] The thermal printer of the present invention includes a mode in which the heating elements of the dots included in each block are dispersed and energized using the dispersion pattern of the present invention described above (hereinafter referred to as distributed energization), and the heat generation of the dots of the blocks. The mode in which the body is energized simultaneously (hereinafter referred to as block energization) can be controlled by switching according to the print data print rate or the line head temperature.

[0068] In an operation mode that combines distributed energization and paper feeding, when dot line data for one line is printed, the printed dots vary according to the dispersion pattern, so the printing state also varies in the paper transport direction. It will be. Even when the block is energized, in the operation mode in which paper is fed each time a block is printed, when one line of dot line data is printed, the printing is shifted in the paper transport direction between adjacent blocks. Happens.

[0069] When the printing states in the two operation modes are compared, the influence of the printing deviation is reduced as the number of dots contained in the block is smaller than the printing deviation in the transport direction at least in the block when the block is energized. However, since block energization energizes in units of blocks, the supply power is limited when the print rate of print data is high. Therefore, the number of blocks that can be energized at the same time is limited, and sticking is likely to occur if the time interval for energization in the same block is long. Therefore, block energization can be applied when sticking is difficult to occur! / And the printing rate is low.

Accordingly, by switching between distributed energization and block energization according to the print rate of the print data, the sticking is suppressed and the deterioration of the print quality is also suppressed. 11 and 12 are flowcharts for explaining the switching operation between the distributed energization and the block energization.

In the flowchart of FIG. 11, the print data transmitted from the host computer is stored in the RAM (S21, S22), and the print data is analyzed to form dot line data (S23). [0072] A print rate is obtained for the dot line data for one line, and compared with a preset print rate (S24). When the printing rate is higher than the set value, distributed energization using a dispersion pattern is performed (S25), and when the printing rate is lower than the set value, block energization is performed in units of blocks (S26). This energization process can be performed for each line.

[0073] Further, since sticking is unlikely to occur when the temperature of the line head portion of the thermal printer is high, block energization is performed when the temperature of the line head portion is high, and the temperature of the line head portion is low. By switching so that distributed energization is performed, the sticking can be suppressed and the deterioration of the print quality can be suppressed.

In the flowchart of FIG. 12, the print data transmitted from the host computer is stored in the RAM (S31, S32), and the print data is analyzed to form dot line data (S33).

Here, the temperature of the line head portion detected by the temperature sensor 37 or the like is compared with a preset temperature (S34). If the temperature of the line head is lower than the set value, perform distributed energization using the distributed pattern (S35). If the temperature of the line head is higher than the set value, block the block. Block energization in units is performed (S36). This energization process can be performed for each line.

FIG. 13 is a diagram for explaining a state in which printing is performed by switching between block energization and distributed energization. FIGS. 13A and 13B show print data, and FIGS. 13C and 13D show the print state. FIG. 13 (a) shows the case where the printing rate is high, and FIG. 13 (b) shows the case where the printing rate is low. When the printing rate is high, distributed energization is performed as shown in Fig. 13 (c), and when the printing rate is low, block energization is performed as shown in Fig. 13 (d).

[0077] In the above-described example, the dispersion pattern is set in advance and stored in the ROM 21, and the dots that are sequentially read out and the dot line data force is selected for printing are also selected. It may be set. FIG. 14 shows an example in which a dispersion pattern is formed for each dot line data of each line. Figure 14 (a) shows the distribution pattern when the first and second lines are energized. Here, each dispersion pattern used in each line is set so that the dots on one line do not leak or overlap. For example, this dispersion pattern can be set using the number of all dots on one line as the number of energization times (in FIG. The number of dots to be energized in each energization operation is determined by dividing by the number of dots. First, the specified number of dots are dispersed and selected from all the dots on one line. A distribution pattern for electricity is formed, and then a predetermined number of dots are dispersed and selected from the remaining dots on one line to form a dispersion pattern for the second energization. Similarly, for the dispersion pattern for the third energization and the dispersion pattern for the fourth energization, a predetermined number of dots are dispersed and selected from the remaining dots on one line to form a dispersion pattern. .

[0078] Figs. 14 (a) and 14 (b) show examples in which a dispersion pattern is formed with one line as a range! / ヽ, but the whole line is divided into a plurality of parts and distributed within the divided range. A pattern may be formed. In Fig. 14 (c) and (d), the entire line is divided into two, and a dispersion pattern is formed within each division range.

[0079] The formation of the dispersion pattern described above can be determined for each line or for each of a plurality of lines. In addition, the formation of a dispersion pattern that covers the entire line, and the formation of a dispersion pattern based on the division range. You can select and combine them according to the print data.

The distribution pattern described above can be stored and used in the RAM 22 every time it is formed by the CPU 2 as shown in FIG. 15, for example.

FIG. 16 shows the operation of the gate array and the selective transfer operation of the dot line data from the first buffer 31 to the second buffer 32 by the distributed data in the mode of forming the distributed pattern. Note that FIG. 16 shows only an example of one formed dispersion pattern.

The CPU 2 forms distributed data (here, [100010010...]) In the distributed pattern forming unit, temporarily stores it in the RAM 22, and sends it to the gate array 23. The gate array 23 sends the distributed data to the buffer in synchronization with the latch signal A. Here, an example of [1000] distributed data is shown.

The second buffer 32 takes in the dot line data selected based on the distributed data sent from the first buffer 31. Here, of the data stored in the first buffer 31, only the bit portion data determined by the distributed data is transferred to the second buffer 32. In Fig. 16, the dot lines of the 1st, 5th, 8th ... th bit defined by the distributed data of [100010010 ...] Only the data is transferred to the second buffer 32, and the dot line data of the other bits is not transferred to the second buffer 32, and no data is maintained. Here, it is assumed that the second buffer 32 is cleared and returns to the initial state after each printing operation.

FIG. 16 shows an example in which the dot line data stored in the first buffer has data (indicated by 參) that enables printing in the bit portion corresponding to all dots. Data (indicated by 參) is stored in the 1st, 5th, 8th,..., Bit portions of 32 (the left end in the figure). If the dot line data of the first bit portion is data that disables printing, the initial state is substantially the same as the bit portion that was selected by this distributed data. The data stored in the second buffer 32 is sent to the line head unit 33, and the line head unit 33 performs dot printing. Printing with one piece of distributed data prints only a part of all dot line data. By printing all of the remaining distributed data, printing for one line is performed.

FIG. 17 shows a case where printing for one line is performed by energization four times. The dispersion pattern forming unit forms a dispersion pattern in each energization. When paper is fed between prints with each dispersion pattern, one line is printed in one cycle from tl to t4. In the next cycle from t5 to t8 (shown in Fig. 17! / ヽ), the next line is printed.

FIG. 18 is a flowchart for explaining a mode in which printing is performed using the formed dispersion pattern.

[0087] First, if the previously formed dispersion pattern remains in the RAM (S41), it is cleared (S41), and a set number of dots is selected from all dots in one line. As described above, the set number can determine the number of dots to be energized in each energization operation by dividing the total number of dots by the number of energizations (S42).

[0088] The selected dot pattern is stored in the RAM as a dispersion pattern (S43), and printing is performed using the dispersion pattern stored in the RAM (S44). Next, the remaining number of dots on one line is selected to form a dispersed pattern for the next energization (S45), and printing is performed using the dispersion pattern stored in the RAM ( S46). Repeat steps S45 and S46 until all the dots on the line are selected (S47). [0089] With the configuration of the present invention described above, the heating element is dispersed over the entire head of the thermal printer and energized, so that it is possible to suppress the bias of the temperature drop portion after heating in the head. Generation of king can be suppressed. In addition, deterioration of print quality can be suppressed by suppressing sticking.

Note that the above configuration examples are examples, and the present invention is not limited to these examples, and includes various modifications.

For example, a circuit for transferring dot line data by distributed data from the first buffer 31 to the second buffer 32 included in the printer mechanism 30 is included in the gate array 23 of the control unit 20. It is also possible.

Claims

The scope of the claims

[1] A method for driving a thermal printer that performs thermal recording on thermal paper fed by a thermal head in which a plurality of heating elements are linearly arranged on a line orthogonal to the paper feeding direction. A plurality of distributed patterns for selecting a heating element to be energized from the one line, and selecting a heating element to be energized from one line of heating element by taking the logical product of the dispersion pattern and one line of print data, and selecting the selected heating element A method for driving a thermal printer, wherein the simultaneous driving is performed by sequentially switching a plurality of distributed patterns.

[2] The dispersion pattern is a pattern for selecting a heating element to be energized from heating elements provided in a block that divides the thermal head,

2. The method for driving a thermal printer according to claim 1, wherein all the heating elements provided in the thermal head are selected only once by the total dispersion pattern.

3. The thermal printer driving method according to claim 2, wherein the dispersion pattern is selected as a heating element that energizes one of the heating elements included in the divided block.

4. The thermal printer driving method according to claim 2, wherein the dispersion pattern is selected as a heating element that energizes a plurality of heating elements included in the divided blocks.

[5] The dispersion pattern is a pattern for selecting a heating element to be energized from all the heating elements included in the thermal head.

6. The thermal printer driving method according to claim 5, wherein each of the dispersion patterns is selected as a heating element for energizing the same number of heating elements.

[7] The thermal printer according to any one of claims 1 to 6, wherein the plurality of dispersion patterns are recorded in advance, and the dispersion pattern to be used is switched by sequentially reading the plurality of dispersion patterns. Driving method.

[8] The plurality of dispersion patterns are sequentially formed while avoiding duplication with respect to one line of print data, and the dispersion patterns are switched by using the sequentially formed dispersion patterns. The driving method of the thermal printer as described in any one of 1 to 6

9. The thermal printer driving method according to any one of claims 1 to 6, wherein in the paper feeding, the thermal paper is conveyed after each energization.

[10] a paper feeding means for conveying the thermal paper;

In a thermal printer comprising a thermal head that linearly arranges a plurality of heating elements on a line perpendicular to the paper feed direction,

A plurality of dispersion patterns for selecting a heating element to be energized from among the plurality of heating elements, switching the plurality of dispersion patterns, and sequentially generating a logical product with print data for one line to generate heat A thermal printer comprising selection means for selecting a body.

[11] The dispersion pattern is a pattern for selecting a heating element to be energized from heating elements provided in a block that divides the thermal head,

11. The thermal printer according to claim 10, wherein all the heating elements provided in the thermal head are selected only once by the total dispersion pattern.

12. The thermal printer according to claim 11, wherein the dispersion pattern is a pattern for selecting one of the heating elements included in the divided block as a heating element to be energized.

13. The thermal printer according to claim 11, wherein the dispersion pattern is a pattern for selecting a plurality of heating elements included in the divided blocks as heating elements to be energized.

[14] The dispersion pattern is a pattern for selecting a heating element to be energized from all the heating elements included in the thermal head,

[15] Each of the dispersion patterns is selected as a heating element for energizing the same number of heating elements. 15. The thermal printer according to claim 14, wherein

[16] The thermal device according to any one of [10] to [15], further comprising recording means for recording the plurality of dispersion patterns and sequentially reading the plurality of dispersion patterns. Printer.

[17] The thermal printer according to any one of [10] to [15], further comprising dispersion pattern forming means for sequentially forming the plurality of dispersion patterns.

18. The thermal printer according to claim 10, wherein the paper feeding means conveys thermal paper after each energization.