JP2817734B2 - Multicolor thermal printing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicolor thermal printing apparatus such as a thermal recording type using a multicolor thermal paper or a thermal transfer type multicolor printing thermal printer using an ink ribbon having a multicolor thermal layer.

[0002]

2. Description of the Related Art One of the typical methods for performing multicolor printing with a conventional thermal printer is to use basic colors of yellow, magenta, and so on.
In order to print the three colors of cyan, first the first color is printed on the recording paper, and then the recording paper is conveyed in the reverse direction to return to the printing position of the first color, and the second color is overlaid thereon to form the color. Further, the same operation is repeated for the third color to realize multi-color printing.

[0003] For example, Japanese Patent Publication No. Sho 59-190867 discloses an energizing signal as shown in FIG. 7 such that the application time for one fixed dot line is sufficient for each color to develop. A method of applying the applied pulse by time division control is disclosed.

For example, Japanese Patent Application Laid-Open No. Hei 7-117251 discloses a method of selecting and applying an application pulse for producing each color for each heating element as shown in FIGS.

FIG. 8 is a circuit diagram of a thermal recording circuit, FIG. 9 is a circuit diagram of one of a plurality of driving circuits used in the thermal recording circuit,
FIG. 10 is a time chart showing the operation of the thermal recording circuit.

In FIG. 8, a thermal recording circuit latches shift registers 30 and 31 for accumulating one line of first color data a1 and a2 respectively from a memory (not shown), and latches parallel outputs from the shift registers 30 and 31. A latch circuit 32, 33 for latching with a pulse d, a shift register for accumulating one line of second color data b from the memory 2, and a register and latch circuit 34 having a latch circuit for latching a parallel output of the shift register; A first time indicating an energizing time of a heating resistor of a thermal head for printing each color of yellow, magenta, cyan, and black based on outputs 101 and 102 of latch circuits 31 and 32 and outputs of shift register and latch circuit 34; To a fourth energization time signal (hereinafter abbreviated as first to fourth signals) 1
One of the driving circuits 35 is selected from among the driving circuits 11 to 114 to drive the heating resistor and not to be energized in the case of white.
-1, 35-2,... 35-n (n is the number of pixels for one line).

The first color data a1, a2 from the memory 2
Are shifted and stored in the shift registers 30 and 31 one pixel at a time in synchronization with the shift pulse c, and the first register of one line is
Is accumulated, all the first color data are output to the latch circuits 32 and 33 and latched. Assuming that one line has 1024 pixels, the shift registers 30 and 31 accumulate 1024-bit data and output the data in parallel. Shift registers 30, 3
1 indicates that the latch circuits 32 and 33 are parallel data 101 and
, The accumulation of the first color data of the next line is started. On the other hand, the second color data b from the memory 2 is stored and latched in the register and latch circuit 34 at the same timing as the first color data a1 and a2. The outputs of the latch circuits 32 and 33 and the register and latch circuit 34 are simultaneously supplied to the drive circuits 35-1 to 35-n.

As shown in FIG. 10, latch circuits 32, 3
3 and the register and latch circuit 34 output one line of the first and second color data in parallel, respectively, while two cycles of the first to fourth signals 111 to 114 correspond to the drive circuit 35-1.
~ 35-n. First one of first to fourth signals
In the cycle, the drive signal 35-
1 to 35-i are selected, and in the next cycle of the first to fourth signals, the driving circuit 35-i is selected by the selection signal 141-2.
(I + 1) to 35-n are selected. Here, i = n /
2. Thus, the selection signals 141-1 and 141-
The reason why the driving of the driving circuit is divided according to 2 is that if the heating resistor arrays for one line are driven simultaneously, a large amount of current flows at once and the power supply capacity must be increased.

The drive circuits 35-1 to 35-n have gates 121 to 126 and a heating resistor 140, respectively, as shown in FIG. The first to fourth signals 111, 112, 113, 114 supplied to the gates 121 to 124 are
As shown in FIG. 10, the energization times t1, t2, t3, and yellow respectively correspond to yellow, magenta, cyan, and black.
A signal indicating t4 is supplied to each of the gates 121 to 124 so as to rise at the same time in a fixed cycle. On the other hand, the gate 12
The first color data 101 and 102 for one pixel from the latch circuits 32 and 33 are stored in the first to fourth signals 11 to 124, respectively.
The first color data 10 is supplied for two periods of
When 1, 102 are yellow “0, 0”, the gate 121
Open, gate 122 when magenta "1, 0", gate 123 when cyan "0, 1", black "1, 1"
At this time, the gates 124 open. Each gate 121-
The output of 124 is supplied to an AND gate 126 via an OR gate 125.

Therefore, the OR gate 125 outputs one of the first to fourth signals 111 to 114. A
The ND gate 126 inputs the output of the OR gate 125, the second color data from the register and latch circuit 34, and the selection signal 141-1 (or 141-2).
The AND gates 126 of the driving circuits 33-1 to 33-i are connected to the selection signal 141-1 and the driving circuits 33 (i + 1) to 33-n.
Of the driving circuits 33- (i + 1) to 33-n is selected by the selection signal 114-2. In addition, when white, that is, when no color is added, the second
Becomes “0”, the AND gate 126
Is closed, and the heating resistor 140 does not generate heat.

As described above, the selection signals 141-1 and 141-1
The drive circuit selected by 1-2 is the latch circuit 3
One of the first to fourth signals 111 to 114 indicating the energizing time is selected in accordance with the first color data 101 and 102 from the second and third color data 33, and the white signal is selected in accordance with the second color data from the circuit 34. At times, the energization time of the heating resistor 140 is controlled so as not to energize.

In addition to the above-described application time control, there is a conventional method in which the applied energy is adjusted by further varying the voltage or current.

[0013]

In the above-described conventional multicolor printing method, the method of reversely transporting the recording paper has a problem that the recording speed is slow because the positioning precision and the recording paper are reciprocated. The reason is that in the method of overwriting by reversing the conveyance, a slight misalignment is likely to occur depending on the set position of the paper in the process of conveying the recording paper, and
This is because it takes twice or more times as long as the transport operation time in one direction in normal black printing.

There is also a method of varying the voltage.
This must be provided for each printing color. Further, in the current variable control method, a variable resistor is required for each heating element. Therefore, in the variable voltage control, when the number of different voltages increases, the power supply circuit becomes complicated and the price increases. Also,
The variable current control has a problem that a large number of heating elements such as a line thermal head require a small variable resistor, and the switching time cannot be ignored.

In the time-sharing control method of the applied pulse shown in FIG. 7, since the applied pulses of the first to third colors are always serially input within a fixed application time, there is a time problem. That is, even if only the third color is printed, 1
There is a problem that high-speed printing cannot be performed because the time is set for the application pulse time for the color and the second color.

Further, in the method shown in FIGS. 8 to 10 in which different applied pulses are selected and input for each heating element, different applied pulses need to be input in synchronization with each other. Therefore, there is a problem that the number of strobe signals serving as the energization signal increases, and it is necessary to always adjust the energization signal to the same recording timing.

An object of the present invention is to provide a multicolor printing thermal printer capable of realizing high-speed printing without changing a voltage or current and using a high-speed device in multicolor printing.

[0018]

According to the present invention, in order to achieve the above object, a recording having a multicolor heat-sensitive layer formed by applying a plurality of heat-meltable inks having different melting points on a substrate in a layered manner. In a multi-color thermal printing apparatus that performs printing with a print head in which a plurality of heating elements are arranged on paper, a plurality of print data corresponding to a color to be printed by each of the plurality of heating elements is input in parallel. And a plurality of selecting means for selecting one of the plurality of heating elements in accordance with the selection signal to provide heat to each of the plurality of heating elements, and a common energizing signal is given to each of the plurality of heating elements. A plurality of driving means configured to apply the energization signal to the heating element corresponding to the selected print data by masking the energization signal for a time corresponding to the selected print data; And to generate and the energizing signal is provided and a control means for controlling the said selection means and said plurality of drive means.

The print data may be generated as print mask data indicating the masking time for each color, and the print mask data may be generated by the control means.

Further, a storage means for storing the print data may be provided, and the selection means may select one of the print data from the storage means in accordance with the selector signal.

[0021]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIG. 1, a preferred embodiment of the present invention is a control unit 100 which generates print mask data for each color and outputs the data.
A print mask data storage unit 400 for storing print mask data of each color in five stages; a gate unit 300 for selecting print mask data for each stage and connecting the selected print mask data to a driving portion of each heating element; It comprises a heating element driving section 200 for driving the heating elements, and a thermal print head 500 in which a number of heating elements are arranged.

Next, a schematic operation will be described. When printing is performed, the control unit 100 first converts multi-line print data for one line into print mask data i to m indicating masking time of a strobe signal, which will be described later, and outputs it to the print mask data storage unit 400. The print mask data i to m may be serial or parallel. However, the print mask data i to m must be input by the number of the heating elements. Is desirably subjected to serial-parallel conversion of the print mask data i to m input to the printer.

Next, the control unit 100 outputs the print mask data i to m to the print mask data storage unit 400, and then outputs a select signal f to the gate unit 300, so that the data is input to the heating element drive unit 200. Print mask data can be selected. Here, select signal f
Are switched over at a constant time width that is sufficient energy to cause each color to be developed by the control unit 100.
Further, during the printing operation for all the colors of one line, the printing mask data for the next line is set in the printing mask data storage unit 400, and the same operation is repeated.

Next, a specific configuration example of FIG. 1 will be described in detail with reference to FIG. 2 includes a clock generation circuit 1, a pulse width control circuit 2, a sampling signal generation circuit 3, a CPU 4, a line memory 5, a control signal generation circuit 6,
A print mask data generation circuit 7, a data selection circuit 8,
The circuit includes latch circuits 9 to 13 for yellow, magenta, cyan, and black, shift register circuits 14 to 18, heating elements 19, driving transistors 20, and gate elements 21. FIG. 2 shows a circuit for driving one heating element 19. In addition, here, a multi-color thermal printing of a thermo-recording type using a multi-color thermal paper having a thermo-sensitive layer in which thermo-meltable inks of four colors of yellow, magenta, cyan, and black having different melting points are coated on a substrate in a layered manner. The case of a device is shown as an example.

The control unit 100 shown in FIG. 1 includes a clock generation circuit 1, a pulse width control circuit 2, a sampling signal generation circuit 3, a CPU 4, a line memory 5, a control signal generation circuit 6, and a print mask data generation circuit shown in FIG. 7. The heating element driving unit 200 in FIG. 1 includes the driving transistor 20 and the gate element 21 in FIG. 2, and the gate unit 300 in FIG. 1 includes the data selector circuit 8 in FIG. The print mask data storage unit 400 in FIG. 1 stores the latch circuits 9, 10, 11, 1 in FIG.
2, 13, shift register circuits 14, 15, 16, 1
7, 18 and the print head 500
It is composed of a heating element 19.

Next, the operation will be described. When receiving a print request, the CPU 4 operated by the clock generation circuit 1 reads one line of print data e from the line memory 5 and outputs it to the print mask data generation circuit 7. The print mask data generation circuit 7 generates print mask data i, j, k, l, m capable of multicolor printing from the input print data, and generates five shift register circuits 14, 15, 16, 1
Output to 7 and 18. At that time, the CPU 4 controls the control signal generating circuit 6 to shift the shift register circuits 14, 15, 1
The print mask data i, j, k,
A shift lock signal h serving as a synchronous capture signal of l and m is output. Here, as the print mask data of each color, data for all the heating elements 19 is serially inputted for one line.

The shift register circuits 14, 15, 16, 1
When the print mask data for all the heating elements 19 is input to the registers 7 and 18, the latch signal g is simultaneously output from the control signal generation circuit 6 to the latch circuits 9, 10, 11, 12 and 13, and the shift register circuit 14 is output. , 15, 16, 17, 18
, Print mask data i, j, k, l,
m are simultaneously stored in the latch circuits 9, 10, 11, 12, and 13, respectively, and are subjected to serial-parallel conversion. CP
When the print mask data is stored in the latch circuits 9, 10, 11, 12, and 13, U 4 outputs a strobe signal “c” as an energization signal of the heating element 19 to the gate element 21 of the heating element driving unit 200. When the strobe signal c is actively output, the sampling signal generation circuit 3 generates a sampling signal b using the clock a from the clock generation circuit 1.

The pulse width control circuit 2 selects a select signal f for switching the print mask data n to r stored in the five latch circuits based on the sampling signal b.
Is output to the data select circuit 8. During the period when the strobe signal c is active in accordance with the print mask data selected by the data select circuit 8, the gate element 21 is turned off.
By performing N · OFF, the drive signal s in which the strobe signal is masked is obtained. By controlling the current by turning on / off the drive transistor 20 in accordance with the drive signal s, the heating element 19 generates heat and printing is performed. Here, multi-color printing can be realized by appropriately controlling the time interval of the select signal f for switching the print mask data.

Next, the principle of the printing operation will be described. FIG. 3 shows a printing example focusing on a certain heating element block. At the first start, if there is print data of any color, all the heating elements 19 are turned on. Next, after t1 seconds,
If there is yellow print data, this heating element 1
9 is turned off first. Next, after t2 seconds, if there is magenta print data, the heating element 19 in that portion is turned off.
It becomes F. Similarly, after t3 seconds, the heating element 19 with the cyan print data is turned off, and after t4 seconds, the heating element 19 with the black print data is turned off.
The strobe signal is sequentially masked for a time corresponding to the selected print mask data. Note that the heating element in a white area where no printing is performed is turned off at the start of energization and does not apply color since no applied energy is applied from the beginning.

FIG. 4 shows the energization time required for the multicolor thermal recording paper to develop four colors of yellow, magenta, cyan and black. The energization time for each color is yellow <magenta <cyan <black. The relationship is large and small. Therefore, each color is sequentially developed after t1, t2, t3, and t4 seconds from the start of energization.

In the multi-color thermal printing apparatus of the present invention, the print mask data is switched every t1, t2, t3, and t4 seconds in FIG. 4 within the effective time of the strobe signal c for printing one dot line. The time during which power is supplied to each heating element 19 changes according to the content of the data, and finally, the applied energy can be varied to perform multicolor printing.

Next, the operation of the embodiment of the present invention will be described with reference to FIG. First, the control unit 100 generates print mask data from print data (step 201). The generated print mask data i to m are input to and stored in the print mask data storage unit 400 (step 202). Next, the control unit 100 outputs the strobe signal c to the heating element driving unit 2 so as to be active (step 203). At the same time, the control unit 10
0 determines whether there is print data for the next line (step 204), and if so, generates print mask data for the next line (step 206).
The print mask data of the next line is stored in 00 (step 209). If there is no print data for the next line, only one processing process is performed.

In the other process after the strobe signal c is activated and output, the control unit 100 has an applied energy sufficient to cause the colors of yellow, magenta, cyan, and black to be developed. The select signal f is output to the gate unit 300 at a certain fixed time interval, and the print mask information stored in the print mask data storage unit 400 is switched (step 205). After selecting all the print mask information, the control unit 100 returns the strobe signal c to make it inactive (step 208), and determines whether or not all lines have been printed (step 210).

When printing on all lines is completed, a series of processing processes is completed, and printing is completed. If printing on all lines is not completed, the thermal recording paper is conveyed by one line to perform a line feed process (step 207). Then, the control unit 100 makes the print mask data of the next line valid again and applies the strobe signal c. At the same time, print mask data for the next line is generated and stored in the print mask data storage unit 400, and the same operation is repeated thereafter.

If it is determined that there is next line print data (step 204), print mask data for the next line is generated and the print mask data storage unit 400
The process of storing the print mask data of the next line must be completed before the strobe signal c becomes inactive in the other processing process (step 208).

The present invention can be applied not only to the thermal recording system but also to a thermal transfer system using an ink ribbon having a multicolor thermosensitive layer. As shown in FIG. 6B, the driving transistor 20 of the driver circuit for driving the heating element is changed from the NPN type of FIG. 6A (the configuration of FIG. 2) to the PNP type, and the base-side gate element 21 is formed. 6A may be changed from the AND element to the NAND element in FIG. Further, in order to reduce the current capacity of the power supply, one-line printing may be divided into two or more.

[0037]

As described above, the first embodiment according to the present invention is described.
The effect of (1) is that it is possible to obtain a printing speed twice or more as compared with the conventional reverse transport overwriting method, and to prevent a printing shift. The reason for this is that there is no reciprocating operation in which reverse conveyance is performed and overwriting is performed for multicolor printing.

The second effect is that the color data of each pixel can be created only by the print mask data, and no high-speed device is required. The reason is that it is not necessary to apply the energizing signal for each color to each pixel at the same recording timing, and all pixels perform multi-color printing by masking one common energizing signal at the same timing using print mask data. Because.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a multicolor thermal printing apparatus according to the present invention.

FIG. 2 is a block diagram showing a specific configuration example of FIG. 1;

FIG. 3 is a configuration diagram for explaining an operation of a certain heating element.

FIG. 4 is a characteristic diagram for explaining a printing principle according to the present invention.

FIG. 5 is a flowchart showing the operation of the embodiment of the present invention.

FIG. 6 is a configuration diagram illustrating a heating element driving unit according to another embodiment of the present invention.

FIG. 7 is a waveform diagram showing the operation of a conventional multicolor thermal printing apparatus.

FIG. 8 is a block diagram of a thermal recording circuit in another conventional multi-color thermal printing apparatus.

FIG. 9 is a configuration diagram showing one drive circuit in the thermal recording circuit.

FIG. 10 is a flowchart showing the operation of the thermal recording circuit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 clock generation circuit 2 pulse width control circuit 3 sampling signal generation circuit 4 CPU 5 line memory 6 control signal generation circuit 7 print mask data generation circuit 8 data select circuit 9 to 13 latch circuit 14 to 18 shift register 19 heating element 20 drive transistor 21 gate element 100 control section 200 heating element driving section 300 gate section 400 print mask data storage section 500 print head c strobe signal f select signal im print mask data nr print mask data s drive signal

Claims (4)

(57) [Claims] 1. A printing head comprising a plurality of heating elements arranged on a recording paper having a multicolor heat-sensitive layer formed by applying a plurality of heat-meltable inks having different melting points on a substrate in a layered manner. A plurality of print data corresponding to a color to be printed by each of the plurality of heating elements is input in parallel, and a selecting means for selecting one of the plurality of print data in accordance with a select signal; A plurality of heating elements are provided to energize each of the heating elements to generate heat, and a common energization signal is given to each of the heating elements, and the energization signal is applied to the heating elements corresponding to the print data selected by the selection means. A plurality of driving means configured to apply the masking at a time corresponding to the selected print data; generating the select signal and the energizing signal to generate the selecting means and the plurality of driving means; A multi-color thermal printing apparatus comprising: 2. The multi-color thermal printing apparatus according to claim 1, wherein the print data is generated as print mask data indicating the masking time for each color. 3. The apparatus according to claim 1, further comprising storage means for storing the print data, wherein the selection means selects one of the print data from the storage means in accordance with the selector signal. Color thermal printing device. 4. The multi-color thermal printing apparatus according to claim 2, wherein said print mask data is generated by said control means.