JPH091847A - Multicolor thermal recording system - Google Patents

Abstract

PURPOSE: To improve the printing speed in a multicolor thermal recording system by simultaneously supplying a plurality of strobe signals having different duty ratios to the blocks of a thermal head by strobe signal generating means. CONSTITUTION: A thermal head 3 having a plurality of heating elements 11 to 1N, 21 to 2N arranged for one line is divided into two blocks 1, 2, and which are driven by first and second driving circuits 4, 5 corresponding thereto. The circuits 4, 5 selectively drive the elements corresponding to data signal DATA when strobe signals STB1, STB2 having ON periods proportional to the energies for color developing red and black are ON. The blocks are simultaneously driven to print the different colors, and since the blocks of print pause state are eliminated, the printing speed is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicolor thermosensitive recording system for performing color recording by applying several kinds of thermal energy to a color thermosensitive recording paper which develops a color according to applied energy.

[0002]

2. Description of the Related Art Generally, in this type of multicolor thermosensitive recording system, for example, a plurality of thermosensitive materials are laminated as a coloring layer to form a thermosensitive paper which develops different colors in respective temperature regions as shown in FIG. 6 (a). Color recording is performed by adding heat energy corresponding to each color. FIG. 7 is a diagram showing a configuration of a main part of a conventional thermal recording apparatus for printing two colors of red and black. Multiple heating elements 1
₁ to 1 _N, 2 ₁ to 2 thermal head _{3 N} formed by one line distributed set to, from the viewpoint of suppressing the temperature rise and current increase due to power concentration, these heating elements 1 ₁ to 1 _N, 2
_{1 to} 2 _N are 2 in the first block 1 and the second block 2
Each of the blocks 1 and 2 is divided and driven by the first and second drive circuits 4 and 5, respectively. First and second
Drive circuits 4 and 5 energize the heating elements 1 ₁ to 1 _N and 2 ₁ to 2 _N corresponding to the data signal DATA only while the strobe signals STB1 and STB2 are on.

As the strobe signals STB1 and STB2, a multi-pulse strobe signal as shown in FIG. 8 is used in order to apply necessary energy without raising the head temperature so much. That is, the print cycle tcy for one line is divided into the red print cycle tcyr and the black print cycle tcyb, and STB1 and STB2 are divided in the red print cycle tcyr.
In this order, a pulse signal with a long ON period (L level period) is sequentially supplied to the first and second drive circuits 4 and 5, and in the black printing cycle tcyb, a pulse signal with a short ON period is first supplied in the order of STB1 and STB2. And to the second drive circuits 4 and 5 sequentially.

As shown in FIG. 6 (b), the duty ratio of these pulse signals determines the temperature rise curves of the heating elements 1 ₁ to 1 _N and 2 ₁ to 2 _N of the thermal head 3, so that black printing is performed. In the case of, the heating elements 1 ₁ to 1 _N and 2 ₁ to
2 _N temperature T is T _L <T <T _H next to, in the case of red printing, the heating elements _{1 1 ~1 N, 2 1 ~2} N temperature T of T _H <
The application period of each pulse is determined so that the temperature T <T _C , which is T and does not reach the region A in which the life of the head is reduced.

[0005]

However, in the above-described conventional multicolor thermal recording system, since printing is performed for one line, printing is performed for each block for each color.
There is a problem that the printing time becomes long.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a multicolor thermal recording system capable of improving the printing speed.

[0007]

A multicolor thermosensitive recording system according to the present invention comprises a plurality of heating elements for applying heat energy to a color thermosensitive recording paper which develops a color according to the magnitude of applied energy. Along with a thermal head in which the plurality of heating elements are divided into a plurality of blocks, a strobe signal generating means for sequentially supplying several types of pulsed strobe signals necessary for developing each color in each block of the thermal head. In the multi-color thermal recording method, the strobe signal generating means outputs a plurality of strobe signals having different duty ratios that do not overlap each other's ON periods and generate energy for producing different colors. It is characterized in that it is supplied to each block of the thermal head at the same time.

More specifically, the strobe signal generating means outputs a first duty signal whose ON period is longer than the OFF period and a second duty signal obtained by inverting the first duty signal in the first period. The second and first strobe signals are simultaneously supplied to the respective blocks of the thermal head, and in the second period following the first period via the off period, the first and second strobe signals are respectively supplied. The thermal head is supplied to each block of the thermal head.

In the multicolor thermal recording system according to the present invention, a duty signal switching means for sequentially switching a plurality of sets of the first and second duty signals having different duty ratios and supplying the strobe signal generating means with the duty signal switching means. It is further characterized by being provided.

[0010]

According to the present invention, a plurality of strobe signals having different ON periods and different duty ratios are simultaneously supplied to the respective blocks of the thermal head. That is, by inserting another pulse-like strobe signal ON period into the pulse-like strobe signal OFF period, the respective blocks of the thermal head are simultaneously driven for printing different colors. Therefore, the blocks are driven simultaneously for printing different colors, and the blocks that are in the print suspension state are eliminated, so that the printing speed is improved. Moreover, according to the present invention, even when each block is driven simultaneously,
Since each block does not turn on at the same time, there is no need to increase the power supply capacity.

In the case of two-color printing such as red and black, for example, a first duty signal whose ON period is longer than the OFF period and a second duty signal obtained by inverting the first duty signal are used in the first period. By supplying each block as the second and first strobe signals, and in the second period as the first and second strobe signals, respectively, the printing speed can be increased without increasing the current value and the temperature. Can be improved. If the off period of both strobe signals is provided between the first period and the second period, it is possible to prevent the temperature of the thermal head from rising more than necessary, and the temperature control becomes easy. .

Further, by sequentially switching a plurality of sets of the first and second duty signals having different duty ratios and supplying them to the strobe signal generating means, it is possible to control printing of more colors.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a main configuration of a thermal recording apparatus for printing two colors (for example, red and black) according to an embodiment of the present invention.

A thermal head 3 having a plurality of heating elements 1 ₁ to 1 _N and 2 ₁ to 2 _N arranged for one line is divided into two blocks 1 and 2, and a first drive circuit corresponding to these blocks. 4 and the second drive circuit 5, respectively. The first and second drive circuits 4 and 5 have heating elements corresponding to the data signal DATA when the strobe signals STB1 and STB2 having ON periods proportional to the energies for producing the colors red and black, respectively, are ON. Drive selectively. The strobe signals STB1 and STB2 are generated by the strobe signal generation circuit 6.

FIG. 2 is a circuit diagram showing the structure of the strobe signal generating circuit 6, and FIG. 3 is a waveform diagram of each section. The strobe signal generation circuit 6 inputs the selection signal SEL, the first duty signal DUTY, and the strobe signal STB, generates the first strobe signal STB1 and the second strobe signal STB2 from these signals, respectively, and drives the drive circuit 4 , 5 respectively.

As shown in FIG. 3, the first duty signal DUTY is a pulsed signal having an ON period t _L longer than the OFF period t _H and is input to the OR circuit 11 and inverted by the inverter 12. And becomes the second duty signal / (negative symbol, the same applies hereinafter) DUTY and is input to the OR circuit 13. In the first half Tcy1 of the printing cycle Tcy for one line, the OR circuits 11 and 13 use the second duty signal based on the selection signal SEL having a cycle equal to the printing cycle Tcy for one line and the inverted signal / SEL by the inverter 14 thereof. / DUTY, and print cycle Tc for one line
In the second half Tcy2 of y, the first duty signal DUTY is passed.

These duty signals DUTY and / DU
The TYs are combined by the AND circuit 15 and supplied to the OR circuit 16, and also inverted by the inverter 17 and supplied to the OR circuit 18. The OR circuits 16 and 18 have a period Tcy.
At the switching timing of 1 and Tcy2, the first and second off periods toff ₁ and toff provided to the output of the AND circuit 15 and its inverted output by the strobe signal STB.
Insert ₂ . As a result, the OR circuits 16 and 18 output the first and second strobe signals S as shown in FIG.
TB1 and STB2 are output.

According to this embodiment, as shown in FIG.
The printing period Tcy for one line is divided into four periods of a first period t ₁ , a first off period toff ₁ , a second period t ₂ , and a second off period toff ₂ . Then, the first strobe signal STB1 is a multi-pulse strobe signal whose ON period is shorter than the OFF period in the first period t ₁ ,
In the second period t ₂ , a multi-pulse strobe signal whose ON period is longer than OFF period is supplied to the first drive circuit 4, respectively. On the other hand, the second strobe signal STB
2 is a multi-pulse strobe signal whose ON period is longer than the OFF period in the first period t _{1 and a} multi-pulse strobe signal whose ON period is shorter than the OFF period in the second period t _{2 and} is the second drive, respectively. It is supplied to the circuit 5.

Therefore, in the first period t ₁ , black printing by the block 1 of the thermal head 3 and red printing by the block 2 are simultaneously executed, and in the second period t ₂ , red printing by the block 1 of the thermal head 3 is performed. The printing and the black printing by the block 2 are executed at the same time. For this reason,
The printing time is only the time spent for the red printing or the black printing, and the printing speed is remarkably faster than the conventional one.

In addition, according to this apparatus, the strobe signals STB1 and STB2 are not turned on at the same time, so that it is sufficient to provide a capacity capable of driving one block of the thermal head 3 as the power capacity. If printing for two colors is continuously performed within one cycle Tcy while the relative feeding with the thermal recording paper is stopped, no printing deviation occurs.

Next, FIG. 4 shows an embodiment in which the present invention is applied to, for example, a four-color printing thermal recording device of black, red, yellow and blue, and FIG. 5 shows a waveform diagram of each part thereof. In this embodiment, in order to generate four kinds of applied energy, the duty ratios are different from each other.
A duty signal switch 7 is provided for switching the duty signals DUTY1 and DUTY2 of various types by the selection signal SEL2 and supplying the duty signal DUTY to the strobe signal generating circuit 6 as the first duty signal DUTY. Select signal SEL
2 is a signal having a cycle equal to the printing cycle Tcy for one line. On the other hand, the selection signal SEL1 supplied to the strobe signal generation circuit 6 is the printing cycle Tcy in this embodiment.
It becomes a signal of 1/2 cycle.

According to this embodiment, the printing cycle Tcy for one line has the first period t ₁ and the first off period toff.
₁ , second period t ₂ , second off period toff ₂ , third
Period t ₃ , third off period toff ₃ , and fourth period t
₄ and the fourth off period toff ₄ are divided into eight. Then, in the first period t ₁ , black printing by the first block and red printing by the second block are simultaneously executed,
In the second period t ₂ , red printing by the first block and black printing by the second block are simultaneously executed, and in the third period t ₃ , yellow printing by the first block and by the second block are performed. Blue printing is executed at the same time, and the fourth period t
_{In 4} , the blue printing by the first block and the yellow printing by the second block are simultaneously executed. Therefore, the printing time is only the time spent for the two colors of the blue printing, the red printing, the black printing and the yellow printing, and the printing speed is remarkably faster than the conventional one.

In the above-described embodiment, the strobe signal ST applied to each block of the thermal head at the same time.
Although B1 and STB2 are signals that are inverted from each other, it suffices that the strobe signals have different ON periods and different duty ratios. Therefore, if, for example, three types of pulses having different duty ratios are simultaneously supplied to three blocks so that the ON periods do not overlap, three-color printing can be performed at the same time.

[0024]

As described above, according to the present invention,
Since each block of the thermal head is supplied with a plurality of strobe signals whose ON periods do not overlap with each other and whose duty ratios are different from each other, each block is simultaneously driven for printing different colors. As a result, there is no block in the print suspension state, and the printing speed can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of a multicolor thermosensitive recording apparatus according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a strobe signal generation circuit in the device.

FIG. 3 is a waveform diagram of a strobe signal in the example.

FIG. 4 is a block diagram showing a main configuration of a multicolor thermal recording apparatus according to another embodiment of the present invention.

FIG. 5 is a waveform diagram of a strobe signal according to another embodiment of the present invention.

FIG. 6 is a diagram for explaining multicolor printing by a thermal head.

FIG. 7 is a diagram showing a main part configuration of a conventional multicolor thermal recording apparatus.

FIG. 8 is a diagram showing a waveform of a conventional strobe signal.

[Explanation of symbols]

1,2 ... block, ₁ 1 to 1 _N, 2 ₁ to 2 _N ... heating element, 3 ... thermal head, 4 ... first driving circuit, 5 ... second driving circuit, 6 ... strobe signal generating circuit, 7 ... Duty signal switcher, 11, 13, 16, 18 ... OR circuit, 12, 14, 17 ... Inverter, 15 ... AND circuit.

Claims (3)

[Claims] 1. A thermal system comprising a plurality of heating elements for applying heat energy to a color thermosensitive recording paper that emits a color according to the magnitude of the applied energy, and the plurality of heating elements are divided into a plurality of blocks. In a multicolor thermal recording system comprising a head and strobe signal generating means for sequentially supplying several types of pulsed strobe signals necessary for developing each color to each block of the thermal head, the strobe signal generating means Is to simultaneously supply to each block of the thermal head a plurality of strobe signals whose ON periods do not overlap with each other and which have different duty ratios for generating energy for producing different colors. Characteristic multicolor thermal recording system. 2. The strobe signal generating means outputs a first duty signal having an ON period longer than the OFF period and a second duty signal obtained by inverting the first duty signal in a second period and a second duty signal in the first period, respectively. The first strobe signal is simultaneously supplied to each block of the thermal head,
The second period following the first period via an off period is supplied to each block of the thermal head as a first strobe signal and a second strobe signal, respectively. Multicolor thermal recording method. 3. A duty signal switching means for sequentially switching a plurality of sets of the first and second duty signals having different duty ratios and supplying the duty signal to the strobe signal generating means. Multicolor thermal recording method described.