JP2008049503A - Printing apparatus and thermal head apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a delay of transmitting speed even when a data size of compression data becomes large. <P>SOLUTION: A printing apparatus and a thermal head apparatus are characterized by being equipped with: a printing part (30) having a plurality of heat emitting elements arranged in a line; a first storing part (38) for storing printing data for a line for printing at the printing part; a controlling part (52) for selecting either that the printing data are transmitted to the first storing part as transmitting data or that compression data which keeps the printing data compressed are transmitted to the first storing part as the transmitting data when the printing data are printed in the printing part; and a selecting part (40) which directly stores the transmitting data in the first storing part or restores the transmitting data to the printing data and then, or stores them in the first storing part, based on selection information indicating that the controlling part selects either the printing data or the compression data. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a printing apparatus and a thermal head apparatus, and more particularly to a printing apparatus and a thermal head apparatus having a plurality of heating elements arranged in a line.

As a printer (printing apparatus), there is a thermal printer that prints data on printing paper by generating heat from a plurality of heating elements arranged in a line. Japanese Patent Application Laid-Open No. H10-228561 discloses a technique having a decoder that restores compressed data of image information for one line in a control device that controls a thermal head. According to Patent Document 1, when data for one line is transmitted to the control device, it can be transmitted as compressed data, so that the data transmission speed can be increased with a simple configuration.
JP 61-30173 A

  However, depending on the content of the print data that is data to be printed, the compressed data obtained by compressing the print data may have a larger data size than the original print data. In this case, the transmission speed is reduced by compressing the print data. An object of the present invention is to suppress a decrease in transmission speed even when the data size of compressed data increases.

  The present invention includes a printing unit having a plurality of heating elements arranged in a line, a first storage unit for storing print data for one line for printing by the printing unit, and the printing data to the printing unit A control unit that selects whether to transmit the print data as transmission data to the first storage unit or to transmit compressed data obtained by compressing the print data to the first storage unit as the transmission data when printing with And based on the selection information as to whether the control unit has selected either the print data or the compressed data, the transmission data is stored directly in the first storage unit, or the transmission data is restored to the print data. And a selection unit stored in the first storage unit. According to the present invention, the control unit can select whether the print data is compressed and transmitted in consideration of the transmission speed of the transmission data or the like, and transmitted without being compressed.

  In the above configuration, the control unit compares the data size of the compressed data and the data size of the print data, and transmits the print data as transmission data to the first storage unit according to a comparison result, The compressed data obtained by compressing the print data can be selected to be transmitted as the transmission data to the first storage unit. According to this configuration, when transmission data is transmitted from the control unit, it can be determined whether or not to compress the transmission data so as to increase the transmission speed.

  In the above-described configuration, a second storage unit that stores the transmission data is provided, and the selection unit stores the transmission data stored in the second storage unit directly in the first storage unit based on the selection information. Alternatively, the transmission data stored in the second storage unit can be restored to the print data via a decoder, and the print data can be stored in the first storage unit. According to this configuration, the transmission data can be reliably stored in the first storage unit as the print data without being restored or restored depending on whether or not the transmission data is compressed data.

  In the above configuration, the selection unit stores the restored print data in a first storage unit, and transmits a development completion signal indicating that the restoration of the transmission data is completed to the control unit. Based on the development completion signal, the print unit can be configured to print the print data. According to this configuration, the print data can be printed after the transmission data is reliably restored.

  In the above configuration, the control unit selects one of a plurality of compression methods, compresses the print data, and transmits it as the transmission data, and the selection information is information indicating which one of the plurality of compression methods is selected. The selection unit can restore the transmission data to the print data based on the selection information. According to this configuration, it is possible to select a compression method with a higher transmission speed depending on the type of print data.

  The present invention includes a printing unit having a plurality of heating elements arranged in a line, a first storage unit for storing print data for one line for printing by the printing unit, and the printing data to the printing unit Selection information for selecting whether to transmit the print data as transmission data to the first storage unit or to transmit compressed data obtained by compressing the print data as the transmission data to the first storage unit And a selection unit that stores the transmission data directly in the first storage unit or restores the transmission data and stores it in the first storage unit. According to the present invention, the transmission data is converted into the print data based on the selection information even when the transmission data is selected in consideration of the transmission speed or the like to transmit the print data with or without being compressed. Can be restored.

  According to the present invention, the present invention can suppress a decrease in transmission speed even when the data size of compressed data increases.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram of the printing apparatus according to the first embodiment. The printing apparatus 10 includes a thermal head unit 20 (thermal head device) and a control device unit 50. The thermal head unit 20 has a function of printing print data on print paper, and includes a printing unit 30, a selection unit 40, a paper transport unit 22, a decoder 24, and a second storage unit 26.

  The printing unit 30 includes a plurality of heating elements 32 arranged in a line for dot printing on a printing paper by generating heat. The first storage unit 38 is a volatile memory such as SRAM, for example, and can store print data corresponding to the heating elements 32 for one line. In the print data, the bit corresponding to the dot corresponding to the dot that prints black on the print paper by the heat generating element 32 is “0”, and the bit corresponding to the dot that the heat generating element 32 does not generate heat and does not print the black dot (still white) The data is “1”. The plurality of heating elements 32 are divided into a plurality of blocks that are energized at once.

  The NAND circuit 36 receives a signal from the first storage unit 38 and a block selection signal from the MCU 52. When the block selection signal is “1”, the NAND circuit 36 outputs “1”, and when the block selection signal is “0”, the NAND circuit 36 outputs the print data in the first storage unit 38. The driver 34 supplies current to the heat generating element 32 when the output of the NAND circuit 36 is “0”, and does not supply current when the output is “0”. One line is divided into, for example, four blocks. The print data held in the first storage unit 38 corresponding to the block can be selectively printed by the block selection signal of the MCU 52. By printing for each block, the current supplied to the heating element 32 at a time can be limited.

  The selection unit 40 stores the transmission data as it is in the first storage unit 38 or returns the transmission data to the print data via the decoder 24 depending on whether the transmission data received from the MCU 52 is print data or compressed data obtained by compressing the print data. This is a circuit for selecting whether to store in the first storage unit 38. The selection unit 40 includes a data reception circuit 42, a data confirmation determination circuit 44, a selection circuit 46, and a development completion signal output circuit 48. The function of each circuit will be described when the flowcharts of FIGS. 2 and 3 are described. The paper transport unit 22 has a function of transporting print paper. The decoder 24 has a function of restoring compressed data. The second storage unit 26 is a volatile memory such as an SRAM, for example, and stores transmission data received from the MCU 52.

  The control device unit 50 converts image data from an external host PC (Personal Computer) 70 into print data that can be printed by the thermal head unit 20, and outputs the print data or compressed data obtained by compressing the print data as transmission data. To do. Further, it has a function of controlling the thermal head unit 20. The control device unit 50 includes an MCU (Micro Controller Unit) 52 (control unit), a volatile memory 54, a non-volatile memory 56, an interface circuit 58, and a paper transport unit drive circuit 60.

  The MCU 52 controls the entire printing apparatus 10 according to a program stored in the nonvolatile memory 56. Specifically, image data and various print control data input from the interface circuit 58 are received, and printing is executed while controlling the operation of the thermal head unit 20.

  The volatile memory 54 is configured by SRAM or the like, and temporarily stores various data necessary for controlling the MCU 52 and data to be printed. The nonvolatile memory 56 is composed of an EEPROM or the like, and stores various data necessary for print control. The data stored in the nonvolatile memory 56 does not disappear even when the power is turned off. When the power is turned on, the data is read by the MCU 52 and written in a predetermined area of the volatile memory 54. The paper transport drive circuit 60 controls the paper transport unit 22 according to an instruction from the MCU 52.

  Next, control of the printing apparatus according to the first embodiment will be described with reference to the flowcharts of FIGS. FIG. 2 shows operations performed by the MCU 52. Referring to FIG. 2, the process waits until image data to be printed is received from host PC 70 (step S10). When the image data is received, the image data is converted into print data that is dot data for one line and stored in the volatile memory 54 (step S12). The print data is converted into compressed data (step S14). It is determined whether the data size (the number of compressed data) of the compressed data is smaller than the data size (the number of print data) of the original print data (step S16). If the data size of the compressed data is smaller than the data size of the print data, the compressed data is used as transmission data (step S22). Selection information, which is a signal indicating that the compressed data has been transmitted, is output to the selection circuit 46 of the selection unit 40 (step S24). If the data size of the compressed data is equal to or larger than the data size of the print data in step S16, the print data is set as transmission data (step S18). Selection information, which is a signal indicating that uncompressed print data has been transmitted, is output to the selection circuit 46 (step S20).

  Wait until data can be transmitted (step S26). After the data can be transmitted, 1-byte transmission data is transmitted to the data receiving circuit 42 (step S28). It is determined whether transmission of data for one line has been completed (step S30). In No, it returns to step S26. In the case of Yes, a signal indicating that transmission of transmission data for one line has been completed is output to the data determination circuit (step S32). It waits until a data expansion completion signal is input from the expansion completion signal output circuit 48 (step S34). After the data development completion signal is input, a block selection signal is output to the printing unit 30 (step S36).

  FIG. 3 is a flowchart showing an operation performed by the thermal head unit 20. The data decision determination circuit 44 determines whether or not the transmission completion signal output in step S32 of FIG. 2 has been received (step S40). In the case of No, in step S28 of FIG. 2, the data reception circuit 42 determines whether one byte of the transmission data transmitted by the MCU 52 has been received (step S42). In No, it returns to step S40. If Yes in step S42, the second storage unit 26 stores the received 1-byte transmission data (step S44). In this way, data for one line is received.

  In the case of Yes in step S40, that is, when transmission of transmission data for one line is completed in steps S26 to S30 in FIG. 2, the selection circuit 46 determines whether the selection information indicates transmission of compressed data (step S46). . In the case of Yes, that is, when the compressed data of the print data is set as the transmission data in step S22 of FIG. 2, the decoder 24 restores the transmission data in the second storage unit 26 and stores the restored print data in the second storage unit 26. Store (step S48). The second storage unit 26 transfers the print data to the first storage unit 38 (step S50). In the case of No in step S46, that is, in the case where the print data is not compressed and transmitted data in S18 of FIG. 2, the second storage unit 26 transfers the print data to the first storage unit 38 (step S50). The development completion signal output circuit 48 outputs to the MCU 52 a development completion signal indicating that the development of the print data in the first storage unit 38 has been completed (step S52). The printing unit 30 prints the print data in units of blocks based on the block selection signal output by the MCU 52 in step S36 of FIG. 2 (step S54).

  Next, an example of compressed data will be described. FIGS. 4 and 5 are examples of compression using the Packed Bits method as a compression method, and show an example (FIG. 4) and an example (FIG. 5) where the data size of the compressed data is smaller than the data size of the original print data. . The print data and the compressed data in FIGS. 4 and 5 are described in hexadecimal notation and are divided every byte (8 bits). Data for each byte from the top of the print data is indicated by d1, d2,. The compressed data consists of headers S1, S2,. In the case of discontinuous data, a value obtained by subtracting 1 from the number of discontinuous data is used as a header. For example, when the number of discontinuous data is 6, the header is [05]. In the case of continuous data, a minus value obtained by subtracting 1 from the number of continuous data is used as a header. For example, when the number of consecutive is 6, the header is [FB].

  Referring to FIG. 4, the print data includes six [55] continuous and six discontinuous data. When this print data is compressed, the compressed data includes six consecutive data as the header S1 [FB], continuous data d1 to d6 [55], and discontinuous data as the header S2. [05] indicating that 6 are arranged, d7 to d12 which are discontinuous data are arranged. Thus, in the case of FIG. 4, 12 bytes can be compressed to 9 bytes by compressing print data.

  Referring to FIG. 5, the print data includes two [00], one [01], two [02], one [03], two [04], and [05]. One is lined up. When this print data is compressed, the compressed data is [FF] indicating that the header S2 is continuous 2 [FF], the data d1 and d2 are [00], and the header S2 is 1 discontinuous data. [00], data d3 [01], and thereafter, headers and data are alternately arranged. In the case of FIG. 5, by compressing the print data, 9 bytes become 12 bytes.

  As described above, there is a case where the data size can be compressed by compressing the print data.

  According to the first embodiment, the MCU 52 (control unit) transmits the print data as transmission data to the first storage unit 38 when the print data is printed by the printing unit 30 as in steps S16 to S24 in FIG. Or the compressed data obtained by compressing the print data is transmitted to the first storage unit 38 as transmission data. Then, as in steps S46 to S50 in FIG. 3, the selection unit 40 directly stores the transmission data in the first storage unit 38 based on selection information indicating whether the MCU 52 has selected either print data or compressed data. Alternatively, the transmission data is restored to print data and stored in the first storage unit 38. Thereby, the MCU 52 can select whether or not to transmit the print data from the MCU 52 to the thermal head unit 20 using the compressed data. Therefore, it is possible to select whether the print data is transmitted after being compressed or not compressed in consideration of the transmission speed of the transmission data.

  Further, as in step S16 of FIG. 2, the MCU 52 compares the data size of the compressed data with the data size of the print data, and transmits the print data as transmission data to the first storage unit 38 according to the comparison result. It is preferable to select whether the compressed data is transmitted to the first storage unit 38 as transmission data. Thereby, when transmitting the transmission data from the MCU 52 to the thermal head unit 20, it is possible to determine whether or not to compress the transmission data so as to increase the transmission speed. Although it is possible to select whether or not to compress depending on whether or not the compressed data is smaller than the data size of the print data as in step S <b> 16, for example, the data size of the compressed data is restored in consideration of the time required for restoration. An amount corresponding to the necessary time may be added and compared with the data size of the print data.

  Furthermore, the selection unit 40 stores the transmission data stored in the second storage unit 26 directly in the first storage unit 38 based on the selection information as in step S46, as in the case of No in step S46. As in the case of Yes in step S46, the transmission data stored in the second storage unit 26 is restored to print data via the decoder 24, and the print data is stored in the first storage unit 38. Accordingly, the transmission data can be stored in the first storage unit 38 as print data without being restored or restored reliably depending on whether or not the transmission data is compressed data.

  Further, as in steps S48 and S50 of FIG. 3, the selection unit 40 stores the restored print data in the first storage unit 38, and as in step S52, the development completion signal output circuit 48 restores the transmission data. Is sent to the MCU 52. Then, the MCU 52 causes the printing unit 30 to print the print data based on the development completion signal as in step S34 in FIG. 2 as in step S36. Thus, the print data can be printed after the transmission data is completely restored.

  The second embodiment is an example in which the compression method can be selected from the compression method A and the compression method B. FIG. 6 is a block diagram of the vicinity of the selection unit 40 and the decoder 24a of the printing apparatus according to the second embodiment. In contrast to the first embodiment, the decoder 24a can restore one of the compression methods A and B in accordance with an instruction from the selection circuit 46. Other configurations are the same as those of the first embodiment, and the description thereof is omitted.

  FIG. 7 is a flowchart illustrating the operation of the MCU 52 of the printing apparatus according to the second embodiment. It is determined whether there is a request for compression method selection from the host PC 70 (step S60). In the case of Yes, information indicating which of the compression methods A or B is requested is output to the selection circuit 46 as selection information (step S62). Proceed to step S64. If No in step S60, it is determined in step S64 whether the interface circuit 58 has received image data from the host PC 70 (step S64). In No, it returns to step S60. In the case of Yes, the image data is converted into print data (step S66). The print data is converted into compressed data of the requested compression method A or B (step S68). Step S16 and subsequent steps are the same as those in FIG.

  FIG. 8 is a flowchart showing the operation of the thermal head unit 20. In step S40, when the compressed data is received, the selection circuit 46 selects a compression method to be restored based on the selection information in step S62 of FIG. 7 (step S70). In the case of the compression method A, the decoder 24a decodes the transmission data in the second storage unit 26 by the compression method A, and the second storage unit 26 stores the restored print data (step S74). In the case of the compression method B, the decoder 24a decodes the transmission data in the second storage unit 26 using the compression method B, and the second storage unit 26 stores the restored print data (step S72). Thereafter, the first storage unit 38 stores the print data of the second storage unit 26 (step S50). The other flow is the same as that of FIG.

  According to the second embodiment, the MCU 52 selects one of a plurality of compression methods as in step S68 of FIG. 7, compresses the print data, and transmits it as transmission data to the data reception circuit 42. The selection information includes information indicating which one of a plurality of compression methods has been selected as in step S62 in FIG. 7 and information indicating whether compression has been performed as in steps S20 and S24. The selection unit 40 restores the transmission data to print data based on the selection information as in steps S70 to S74 of FIG. As a result, it is possible to select a compression method with a higher transmission speed depending on the type of image data or print data. For example, the compression method can be selected depending on whether the image data is character data or pattern data. In the second embodiment, the host PC 70 selects the compression method. However, the MCU 52 may recognize the image data received by the interface circuit 58 and select the compression method.

  Transmission of print data from the control device 50 to the thermal head unit 20 may be performed by serial communication or parallel communication. However, when printing data is serially transmitted from the control device unit 50 to the thermal head unit 20 as in the first and second embodiments, the transmission time becomes longer. Therefore, it is effective to apply the present invention. In the first embodiment, the Pack Bits method has been described as an example of the data compression method. For example, the Switched Run Length Encoding method, the LZ77 method, the LZ78 method, the LZW method, the LZH method, and the ZIP method can be used. Further, as the compression method of the second embodiment, for example, two of the above methods can be used.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

FIG. 1 is a block diagram of the printing apparatus according to the first embodiment. FIG. 2 is a flowchart illustrating the operation of the MCU according to the first embodiment. FIG. 3 is a flowchart showing the operation of the thermal head unit of the first embodiment. FIG. 4 is a diagram showing data in which the data size of the compressed data is smaller than the data size of the print data. FIG. 5 is a diagram illustrating data in which the data size of the compressed data is larger than the data size of the print data. FIG. 6 is a block diagram of the vicinity of the selection unit and the decoder of the printing apparatus according to the second embodiment. FIG. 7 is a flowchart illustrating the operation of the MCU according to the second embodiment. FIG. 8 is a flowchart showing the operation of the thermal head unit of the second embodiment.

Explanation of symbols

10 Printing device 20 Thermal head (thermal head device)
24, 24a Decoder 26 Second storage unit 30 Printing unit 32 Heating element 34 Driver 36 NAND circuit 38 First storage unit 40 Selection unit 42 Data reception circuit 44 Data confirmation circuit 46 Selection circuit 48 Development completion signal output circuit 50 Control device unit 52 MCU
54 Volatile memory 56 Nonvolatile memory 58 Interface circuit 60 Paper transport unit drive circuit 70 Host PC

Claims (6)

A printing unit having a plurality of heating elements arranged in a line;
A first storage unit for storing print data for one line for printing by the printing unit;
When the print data is printed by the printing unit, the print data is transmitted as transmission data to the first storage unit, or compressed data obtained by compressing the print data is transmitted as the transmission data to the first storage unit. A control unit for selecting whether to
Based on the selection information indicating whether the control unit has selected the print data or the compressed data, the transmission data is stored directly in the first storage unit, or the transmission data is restored to the print data and And a selection unit stored in the first storage unit.   The control unit compares the data size of the compressed data and the data size of the print data, and transmits the print data as transmission data to the first storage unit or compresses the print data according to the comparison result. The printing apparatus according to claim 1, wherein whether to transmit the compressed data as the transmission data to the first storage unit is selected. A second storage unit for storing the transmission data;
The selection unit stores the transmission data stored in the second storage unit directly in the first storage unit based on the selection information, or the decoder stores the transmission data stored in the second storage unit. The printing apparatus according to claim 1, wherein the print data is restored to the print data and the print data is stored in the first storage unit. The selection unit stores the restored print data in the first storage unit, and transmits a development completion signal indicating that the restoration of the transmission data is completed to the control unit,
The printing apparatus according to claim 3, wherein the control unit causes the printing unit to print the print data based on the development completion signal. The control unit selects one of a plurality of compression methods, compresses the print data, and transmits it as the transmission data.
The selection information includes information on which one of the plurality of compression methods is selected,
The printing apparatus according to claim 1, wherein the selection unit restores the transmission data to the print data based on the selection information. A printing unit having a plurality of heating elements arranged in a line;
A first storage unit for storing print data for one line for printing by the printing unit;
When the print data is printed by the printing unit, the print data is transmitted as transmission data to the first storage unit, or compressed data obtained by compressing the print data is transmitted as the transmission data to the first storage unit. A selection unit that directly stores the transmission data in the first storage unit or restores the transmission data and stores the transmission data in the first storage unit, based on selection information that is selected to be performed. Thermal head device to perform.

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