JP2002137427A - Thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal printer which can read out printing data for at least two colors corresponding to one line of a thermal head at a time, when an article to be printed is printed with at least two colors. SOLUTION: A RAM containing a picturing buffer region which stores a red image of 1-dot as '10' and stores a black image of 1-dot as '11' in a memory resion for 2-bits in a line, a printing head which can prints the article to be printed with a specified color among a plurality of colors and a control means which specifies a color expressed by printing data and controls printing motion of the printing head are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a thermal printer, and more particularly, to a thermal printer having a function of printing characters, bar codes, and the like in two or more colors on an object to be printed such as paper or a label.

[0002]

2. Description of the Related Art In recent years, thermal printers having a function of performing two-color printing on an object to be printed have been commercialized. For example, Japanese Patent Application Publication (JP-A-61-192568) discloses a thermal printer including a memory including two drawing buffer areas of the same capacity for separately storing print data of two colors. I have. In this method, print data for one line is alternately read from each drawing buffer area, and a process of alternately printing each color on one line of the print object is repeated, thereby printing two colors on the print object.

[0003]

However, in such a conventional thermal printer, a drawing buffer area for each color is used. Therefore, when two-color printing is performed on an object to be printed, one line of a thermal head is printed. On the other hand, it is necessary to alternately read the print data for each color from one line in each drawing buffer area. In view of the above circumstances, the present invention provides a thermal printer that can read out print data for two or more colors corresponding to one line of a thermal head at a time when printing on a print target in two or more colors. The purpose is to provide.

[0004]

In order to solve the above-mentioned problems, a thermal printer according to the present invention includes a plurality of memory areas arranged two-dimensionally in a memory area for two bits in one line. A memory including a drawing buffer area for storing print data for one dot which can take one of the colors; a print head capable of printing on a print target in one of a plurality of colors designated; Control means for controlling a printing operation of the print head by designating a color represented by the print data.

According to the present invention, print data for one dot which can take one of a plurality of colors is stored in a memory area for two bits in one line in a drawing buffer area of a memory. Therefore, by calling one line of the drawing buffer area, two lines corresponding to one line of the print head are read.
It is possible to read out print data for more than one color at a time.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram illustrating an overall configuration of a thermal printer according to an embodiment of the present invention. In the present embodiment, a thermal printer used for printing a label will be described as an example. In the thermal printer 10, the label continuum 13 is connected to the supply shaft 14.
It is wound. The label continuum 13 is formed by temporarily attaching the label 11 to the mount 12 so as to be peelable. The label 11 is a two-color thermal paper capable of emitting red and black, for example, an upper layer that emits red when the first temperature is reached, and a second temperature that is higher than the first temperature. Then, it is constituted by the lower layer that develops black.

The stepping motor 16 drives the platen roller 15 via the belt 17 so that
2 is transported from right to left. The transport of the mount 12 is controlled based on the detection result of the sensor 19, and the label 11 is printed by the thermal head 18. In the present embodiment, the head width of the thermal head 18 is set to 108 mm.
, And printing up to 864 dots at a time is possible. In such a printing operation, the control unit 20 controls the operation of each unit.

FIG. 2 is a block diagram showing the configuration of the control unit of the thermal printer shown in FIG. RO of control unit 20
An M (read only memory) 21 stores a control program for the operation of each unit in advance. On the other hand, RAM (random a
The ccess memory 22 temporarily stores various data such as print data and setting data. These data are
For example, from the computer 28, the external interface 27
Via the RAM 22. CPU of control unit 20
The (central processing unit) 23 controls the motor control unit 24, the sensor control unit 25, and the thermal head control unit 26 according to a control program stored in the ROM 21. Then, under the control of the CPU 23, the motor control unit 24
Operates the stepping motor 16 and the sensor control unit 2
5 activates the sensor 19. Each unit of the control unit 20 operates by being supplied with power from the power supply unit 29.

FIG. 3 is a diagram showing the division of the memory area of the RAM shown in FIG. A part of the memory area of the RAM 22 is used as a drawing buffer area 30. In the present embodiment, the maximum printable area in the transport direction of the label 11 (the direction perpendicular to the width direction of the thermal head 18) is set to 200 mm using data stored in the drawing buffer area 30 at one time. Up to 1600
The goal is to print lines. In this case, the number of vertical lines required in the drawing buffer area 30 is 1600.

FIG. 4 shows one of the drawing buffer areas shown in FIG.
It is a figure showing division of a line. One line of the drawing buffer area has a capacity of 1728 bits (216 bytes) for storing print data having a bit number twice as large as the number of dots of the thermal head. Here, 8 bits (1 byte) constitute one block. Since the number of vertical lines in the drawing buffer area is 1600, the capacity of the drawing buffer area is 216 bytes × 160.
0 lines = 345,600 bytes (1 kilobyte = 10
If it is 24 bytes, it is 337.5 kilobytes). Such a drawing buffer area can be realized by doubling the horizontal direction and halving the vertical direction of a conventionally used drawing buffer area.

As shown in FIG. 4, one of the drawing buffer areas
In one block, by using a memory area for two consecutive bits, non-printing dots are stored as 2-bit print data "00", and dots printed in red are stored as 2-bit print data "10". The dot that is stored and printed in black is the 2-bit print data “1”.
1 ". The print data “01” is
Although it is not used at present, it can be used for printing three colors in the future.

Here, a process of storing print data in the drawing buffer area will be described with reference to FIG. First, in step S10, it is desirable to reset the drawing buffer area and set all data to "0". After that, print data and color data are input. In the print data, dots to be printed are represented by “1”, and dots that are not printed are represented by “0”. In the color data, dots printed in black are represented by “1”, and dots printed in red are represented by “0”.

Next, in step S12, the input print data is enlarged twice in the horizontal direction. That is, when printing is performed on the first dot of the first line of the label, the print data “1” corresponding to that dot is set to “11”,
When not printing on a dot, the print data “0” corresponding to the dot is set to “00”.

Further, in step S13, it is determined based on the color data whether the color of the first dot of the first line of the label is red or black. If it is determined that the color is red, the print data "11" is converted to "10" in step S14. This conversion can be performed, for example, by calculating the logical product of the print data “11” and the 2-bit data “10”. Then, in step S15, the first of the drawing buffer area
"10" is stored in the memory area of the first bit and the second bit in the first block of the line.

On the other hand, if it is determined in step S13 that the color of the image to be printed on the first dot of the first line of the label is black, then in step S16, the first block of the first line of the drawing buffer area is determined. "11" is stored in the memory area of the first bit and the second bit in. Thereafter, the second dot to the sixteenth dot on the first line of the label
By repeating the same process up to the 864th dot of the 00 line, all information on printing of this label is stored in the drawing buffer area.

Steps S13 and S14
In the processing in, the logical product may be obtained between the lower bits of the print data and the color data. If the color of the dot is red, the print data "11" is converted to "10" by taking the logical product of the lower bit "1" of the print data "11" and the color data "0". . On the other hand, when the color of the dot is black, the print data remains "11" even when the logical product of the lower bit "1" of the print data "11" and the color data "1" is obtained.

In the present embodiment, the case of printing in two colors of red and black has been described. However, "0" is stored in the memory area for two consecutive bits in the block of the drawing buffer area.
By storing "1", it is possible to print in a third color other than red and black. Therefore, it is possible to cope with a case where a printing function using the third color is added in the future without increasing the capacity of the drawing buffer area.

Referring again to FIG. The thermal head controller 26 drives the thermal head 18 based on the print data read from the drawing buffer area under the control of the CPU 23. More specifically, when printing in red on a label, the thermal head control unit 26 stores the 2-bit print data read from the drawing buffer area in one.
The data is converted into red print data of bits and converted to the thermal head 18.
Transfer to At this time, the thermal head controller 2
6 supplies a first electric energy (for example, 0.2 mJ) to a heating element of the thermal head 18 for performing printing. By these operations, the dots printed on the label are heated to the color development temperature of red, and the color red is developed.

On the other hand, when printing on a label in black, the thermal head controller 26 converts the 2-bit print data read from the drawing buffer area into 1-bit black print data and sends it to the thermal head 18. Forward. At this time, the thermal head control unit 26 supplies the second heating element, which is larger than the first electric energy, to the heating element of the thermal head 18 for performing printing.
(For example, 0.5 mJ). By these operations, the dots printed on the label are heated to the black color development temperature, and develop black color.

Here, referring to FIG. 6 and FIG.
A method of converting bit print data into red or black 1-bit print data will be described. For example, if the binary number stored in the first to eighth bit memory area of the block in the drawing buffer area is “00100011”
, The binary number “0010” stored in the upper 4-bit memory area corresponds to the hexadecimal “2”, and the binary number “00” stored in the lower 4-bit memory area.
"11" corresponds to hexadecimal "3".

Therefore, in the conversion table shown in FIG. 6, "41" in the column at the intersection of the column whose "upper" column is "2" and the row whose "lower" column is "3" is selected. I do. Here, the hexadecimal number “4” located above “41” corresponds to the binary number “0100”, and is a red print indicating that the second dot out of four consecutive dots is to be printed in red. Data. Also, a hexadecimal “1” located below “41” corresponds to a binary “0001”, and is black print data indicating that the fourth dot of four consecutive dots is to be printed in black. It has become. When red printing is performed first, only red printing data for one line is accumulated and transferred to the thermal head.

Similarly to the above, in the conversion table shown in FIG. 7, "14" of the column at the intersection of the column whose "upper" column is "2" and the row whose "lower" column is "3". Select ". Here, a hexadecimal “1” located above “14” corresponds to a binary “0001”, and is a black print indicating that the fourth dot out of four consecutive dots is printed in black. Data. Also, a hexadecimal number “4” located below “14” corresponds to a binary number “0100”, and is red print data indicating that the second dot of the continuous four dots is to be printed in red. It has become. When black printing is performed after red printing for one line is completed, only black printing data for one line is accumulated and transferred to the thermal head.

Next, the operation timing of two-color printing of the thermal printer according to the present embodiment will be described with reference to FIGS. FIG. 8 is a timing chart showing the operation timing of two-color printing of the thermal printer. First, red print data to be printed on the first line of the label 11 is transferred to the thermal head 18. Then, by generating a latch clock to fix the red print data and setting the strobe signal to low level, the designated dot on the first line of the label 11 is printed in red.

Next, black print data to be printed on the first line of the label 11 is transferred to the thermal head 18. Then, by generating a latch clock, fixing the black print data, and setting the strobe signal to low level,
The designated dot on the first line of the label 11 is printed in black. Note that, in synchronization with the end of black printing, the label 11
The transfer of the red print data to be printed on the second line to the thermal head 18 may be started. At this time, by driving the stepping motor 16, the second
The backing paper 12 is conveyed so that the line comes to the printing position of the thermal head 18, and the same operation is repeated for the second and subsequent lines of the label 11, whereby the label 11 is printed in two colors.

According to this embodiment, by using a memory area for two consecutive bits of the drawing buffer area,
The one-dot red image is stored as “10”, and the one-dot black image is stored as “11”. That is, print data for two colors to be printed on each line of the label is stored in a mixed manner on each line of the drawing buffer area. Therefore, by calling each line of the drawing buffer area, print data of two colors corresponding to each line of the printing object can be read at a time.

[0026]

As described above, according to the present invention,
When printing in two or more colors on a printing object, print data for two or more colors corresponding to one line of the print head can be read at a time.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall configuration of a thermal printer according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a control unit of the thermal printer shown in FIG.

FIG. 3 is a diagram showing a division of a memory area of a RAM shown in FIG. 2;

FIG. 4 is a diagram showing a section of one line of a drawing buffer area shown in FIG. 3;

5 is a flowchart showing a process of storing print data in a drawing buffer area shown in FIG.

6 is a diagram showing an example of a conversion table used when converting 2-bit print data stored in the drawing buffer area shown in FIG. 4 into red or black 1-bit print data.

FIG. 7 is a diagram showing another example of a conversion table used when converting 2-bit print data stored in the drawing buffer area shown in FIG. 4 into red or black 1-bit print data.

FIG. 8 is a timing chart showing two color printing operation timings of the thermal printer according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Thermal printer 11 Label 12 Backing paper 13 Label continuous body 14 Supply axis 15 Platen roller 16 Stepping motor 17 Belt 18 Thermal head 19 Sensor 20 Control part 26 Thermal head control part 30 Drawing buffer area

Claims (3)

[Claims] A print data for one dot which can take one of a plurality of colors is stored in a memory area for two bits in one line among a plurality of memory areas arranged two-dimensionally. A memory including a drawing buffer area, a print head capable of printing on a printing object in one color specified from a plurality of colors, and a printing operation of the print head by specifying a color represented by the print data. And a control means for controlling the thermal printer. 2. The printing apparatus according to claim 1, wherein the memory stores print data for one dot in a memory area for two consecutive bits in one line of the drawing buffer area.
The described thermal printer. 3. The printing apparatus according to claim 2, wherein the control unit creates print data for one line for a plurality of colors based on print data read from a memory area for one line in a drawing buffer area of the memory, and 3. The thermal printer according to claim 1, wherein the print data for one line is transferred to the print head in a time-division manner.