KR0141116B1 - Video printing apparatus and method - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video printer apparatus and a method thereof, comprising: a printer apparatus for introducing an image signal from a signal input source and expressing an energization factor to a thermal transfer head composed of a heating element after comparing gray levels and preset gray values in units of lines; The heating period is variable in response to the temperature change of the TPH, including a temperature sensor for detecting the temperature of the thermal head and a temperature compensator for generating a strobe signal for controlling the heating period in response to the result of the temperature sensor and supplying the thermal head. In this case, the density of the color for each gray level is constantly expressed, thereby making it possible to print a high quality image and to reduce the amount of hardware.

Description

Video printer device and method

1 is an overall block diagram of a conventional video printer apparatus.

2 is a block diagram according to an embodiment of a video printer apparatus according to the present invention.

3A to 3C are waveform diagrams of signals generated in the strobe signal generator shown in FIG.

4 is a block diagram according to another embodiment of a video printer apparatus according to the present invention.

* Explanation of symbols for main parts of the drawings

110: image signal processing circuit 120: image display circuit

130: selection unit 140: color converter

150: line memory 160: intermediate tone converter

170: temperature compensation unit 180: TPH

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video printer apparatus, and more particularly, to a video printer apparatus and a method for printing in high quality by varying a heat generation period of a thermal transfer head in response to a temperature change of the thermal transfer head.

Conventionally, as shown in FIG. 1, the red, green, and blue signals of an analog image signal transmitted from a signal input source such as a video camera or a television in the A / D conversion unit 11 are displayed. To enter the digital signal format.

In the first selector 12, a signal output from the A / D converter 11 is transmitted from a digital signal input source such as a personal computer or a graphic computer through a protocol such as GP-IB, SCSI, CENTORNICS, or the like. Select digital graphic image data.

The memory controller 15, which controls the writing and reading timing of data, stores the selection signal of the first selection unit 12 in the memory 13 on a frame or field basis under the control of the microcomputer 14.

The D / A converter 21 converts the data stored in the memory 13 into an analog signal, and the encoder 22 converts the data into an analog signal and displays it on a display unit (not shown) such as a monitor and a TV receiver.

The second selector 31, which is composed of a multiplexer, sequentially switches one signal for the R, G, and B data stored in the memory 13, and the second converter 32 converts the Y ( Yellow), M (Magenta) signal complementary to the G signal, and C (Cyan) signal to the R signal.

The line memory 34 stores the data output from the color converter 32 as lines, and the intermediate tone converter 35 compares a preset gray level with a gray level, and then generates a strobe signal corresponding to a heating time for each gray level. Is generated and the TPH 36 is driven during this heat generation time period to perform color printing.

On the other hand, the shift register 36a of the TPH 36 shift-stores the grayscale-compared data DATA from the halftone converter 35 by one bit, and the latch 36b intermediate-controls the output of the shift register 36a. Temporary storage is performed according to the latch signal LATCH output from the affected part 35, and the heating element 36c generates the output of the latch 36b according to the strobe signal STROBE having a different time width for each gray level.

Here, the internal temperature change of the TPH 36 is changed by the heat generation during the operation of the TPH 36, which immediately leads to the result that the color density of the screen printed by the TPH 36 is different from the original. In most video printer apparatuses, the temperature compensator 33 is connected between the color converter 32 and the line memory 34 to compensate for temperature, thereby preventing distortion of color density due to temperature change.

In the temperature compensating unit 33, the temperature compensation of the TPH 36 is made to vary the value of the image data so as to compensate for the temperature.

For example, assuming that the value of arbitrary image data is 51 and the image data has 256 gray scale resolution, the temperature compensator 33 changes the temperature value by changing the values according to the current TPH temperature as follows. To be

Original image data value: 51

Just as having different data values depending on the TPH temperature, all image data values have variable values for each temperature. By the way, the variable value for temperature compensation does not change linearly according to the size of the image data value, but varies linearly. In other words, the variable value is composed of extracted values by statistical values. It is stored in the same memory.

There are two problems with this temperature compensation.

First, subdividing the steps of temperature in detail for accurate temperature compensation increases the burden on hardware. That is, as the amount of temperature compensation data increases, a large amount of memory (RAM, ROM) must be used. For example, when 9-bit 256-gradation image data is compensated for temperature, each time one temperature step is increased, 256 bytes or 3 colors of memory (3 x 256 BYTE) are required when considering Y, M, and C colors.

Second, accurate real-time temperature compensation is difficult. This is because there are many time intervals at the time of reading image data and performing temperature compensation and at the time of actual printing.

That is, the TPH has the most significant temperature change when printing with the gray scale comparison in the halftone conversion section 35, but reads the image data from the memory 13 and compensates the temperature in the temperature compensating section 33 so that the line memory 34 It is outputted to the real-time temperature compensation.

Therefore, in order to overcome the above-described problems, an object of the present invention is to video in which the density of the color for each gray level is constant by varying the heating period in response to the temperature change of the thermal transfer head (TPH) in the sublimation thermal transfer printer device To provide a printer device.

It is also an object of the present invention to provide a video printer method in which the heat generation period is varied in response to a temperature change of the TPH, whereby the color density of each gray level is constantly expressed.

In order to achieve the above objects, the video printer device according to the present invention is a printer device for introducing the image signal from the signal input source and expressing the energization factor to the thermal transfer head composed of a heating element after the gray level value preset in line units and gray level comparison In:

Detecting means for detecting a temperature of the thermal transfer head;

And a temperature compensating means for generating a strobe signal for controlling the heat generation period corresponding to the result of the detecting means and supplying the strobe signal to the thermal transfer head.

In addition, the video printer method according to the present invention is a printing method in which an image signal is inputted from a signal input source, and a conduction factor expression is performed on a thermal transfer head composed of a heating element after comparing gray levels and preset gray values in units of lines:

A detecting step of detecting a temperature of the thermal transfer head;

And a temperature compensation step of generating a strobe signal indicative of the heat generation period and supplying the strobe signal to the thermal transfer head according to the detection result of the detection step.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of a video printer device and method according to the present invention.

2 is a block diagram according to an embodiment of a video printer apparatus according to the present invention.

2 shows an image signal processing circuit 110 for storing an image signal flowing from a signal input source in frames as a digital signal, and a result of signal processing in the image signal processing circuit 110. The image signal display circuit 120 to be displayed on the display, the selection unit 130 for selecting the R, G, and B signals read out from the image signal processing circuit 110, and the selection unit 130 selected by the selection unit 130. The R, G, and B data includes a color converter 140 for converting C, M, and Y color signals having a complementary color relationship, a line memory 150 for storing the output of the color converter 140 on a line basis, and a line memory ( The data is compensated by inputting the halftone conversion unit 160 for controlling the data writing and reading of the data 150 and the gray level comparison of the read data, and the TPH temperature data and the section data output from the halftone conversion unit 160 as addresses. Look-up table for storing data (171), in 1 heat cycle A strobe signal generator 173 for generating a strobe signal of a heat generation period corresponding to a result of comparing and comparing the counter 172 and the output of the look-up table 171 with the counter 172 for counting a corresponding time. The temperature compensator 170, the shift register 181 for storing bit-wise data DATA compared from the halftone converter 160, and the output of the shift register 181. The latch 182 temporarily stores according to the latch signal LATCH output from the 160, and the heating element 183 generates heat in response to the strobe signal output from the strobe signal generator 173. do.

In another embodiment of the present invention, as shown in FIG. 4, a subtractor 174 for detecting a difference between the TPH temperature data and the reference temperature data, a comparator 175 for comparing the output of the subtractor 174 with a reference value, and a comparator A first counter 176 including an up / down counter for counting an output signal of 175, a second counter 177 for counting a time corresponding to one heating period, and an output of the first counter 176; The output of the two counters 177 has the same configuration except that the strobe signal generator 176 which generates the strobe signal of the heating period corresponding to the result of the comparison is compared.

Next, the operation of FIGS. 2 and 3 will be described.

According to FIG. 2, the image signal processing circuit 110 and the image display circuit 120 have the same configuration as the image signal processing circuit 10 and the image display circuit 20 shown in FIG.

In the selector 130, the R, G, and B data are sequentially switched one by one. In the color converter 140, the B signal is a Y signal having a complementary color relationship, and the G signal is an M signal having a complementary color relationship. The signal is converted into a C signal having a complementary color relationship.

In the line memory 150, the output of the color converter 140 is written in lines.

The data read from the line memory 150 is compared in gray scale by the halftone conversion unit 160 and shift-stored bit by bit in the shift register 181.

When one line of gray level data is stored in the shift register 181, the data is temporarily stored in the latch 182 according to the latch signal LATCH output from the halftone converter 160.

Meanwhile, in the look-up table 171, digital TPH temperature data is input to an address from a temperature sensor (not shown) for detecting the temperature of the TPH 180, and the Y / M / C from the halftone conversion unit 160 is changed according to the address. Input color data to access and output temperature data compensated for each gradation in the corresponding color. Then, the memory location in which data corresponding to the temperature-compensated heat generation time corresponding to the applied temperature and color is stored is accessed and output.

The counter 172 counts the time corresponding to one heat generation cycle.

The strobe signal generator 173 is configured as a comparator and generates a strobe signal having a different heating time according to a result of comparing and comparing the data output from the lock-up table 171 with the data output from the counter 172. Supply to 183.

That is, if the TPH temperature is high, the output of the look-up table 171 outputs data lower than the current TPH temperature, and the time corresponding to the heat generation period is constant at the counter 172, and according to the output of the look-up table 171. Since the comparison values differ, the strobe signal is output for a long time or a short time according to the difference.

The waveforms shown in FIGS. 3A to 3C show that the heating period varies with the temperature of the TPH.

T1 to the next T1 is one cycle of heat generation. During one cycle of exotherm, it is divided into time of exothermic time and time of non-heating. The low section of T1 to T2 generates heat, and the high section of T2 to T1 does not generate heat. Based on the exothermic time when the temperature is appropriate (Fig. 3A), the temperature is compared with when it is lower than the appropriate temperature. That is, when the temperature is low, as shown in FIG. 3B, the heat generation time (T1-T2) is long, and when the temperature is high, as shown in FIG. 3C, the heat generation time (T1-T2) is short.

The heating element 183 generates the output of the latch 182 during the active period of the strobe signal STROBE output from the strobe signal generator 173.

Therefore, when the temperature of the TPH 180 is low, the heat generation time is increased, and when the temperature of the TPH 180 is high, the heat generation period is shortened to compensate for the difference in color density according to the temperature change and to print at a constant temperature.

In summary, the first embodiment described above is a method in which an alarm corresponding to a different heating time for each temperature is stored in a ROM or RAM, and temperature information is applied to its address input to read and use information corresponding to the heating time. . In this case, the required memory size is about a byte of the temperature step. Furthermore, if the heating time is compensated differently for each color, the information corresponding to the number of temperature steps is stored in each of R, G, and B. It is about.

That is, a byte of (number of temperature steps x number of colors) is required, which is very small compared to the size of the memory of the temperature compensating part of the existing video printer apparatus.

And controlling the heating time is done at the time of printing itself, so real-time temperature compensation.

4 is another embodiment of the video printer device according to the present invention. Since the same components of FIG. 2 are already described with reference to FIG.

Referring to FIG. 4, the subtractor 174 of the temperature compensator 170 calculates a difference between the temperature data detected by a temperature sensor (not shown) and a reference temperature data that detects the temperature of the TPH 180.

The comparator 175 compares whether the subtracted value of the subtractor 174 is greater than or equal to the reference value 0, and outputs a signal E1 if greater than zero, and outputs a signal E2 if less than zero. The signal E1 is a low logic signal, and the signal E2 is a high logic signal.

The first counter 176 counts down when the E1 signal is output from the comparator 175, and counts up when the E2 signal is output from the comparator 175 to output the strobe signal to the strobe signal generator 178.

For example, when the comparison result shows that the TPH temperature is higher than the reference value, the state of the first counter 176 goes down through the signal E1. In this case, the larger the difference between the comparison results, the more the down operation of the first counter 176 proceeds. The first counter 176 is down via the signal E1 until the TPH temperature is lowered to approach the reference temperature.

On the other hand, when the temperature of the TPH is lower than the reference temperature, the first counter 176 is up through the signal E2. Likewise, if the difference between the results is large, the first counter 176 is made to proceed up a lot, and the temperature of the TPH is increased so that the first counter 176 is up until the temperature of the TPH approaches the reference temperature.

The second counter 177 counts the time corresponding to one heating cycle.

The strobe signal generator 178 generates a strobe signal according to a result of comparing and comparing the output of the first counter 176 with the output of the second counter 177.

That is, when the TPH temperature is high, the output of the first counter 176 outputs data lower than the current TPH temperature and the time corresponding to the heat generation period in the second counter 177 is constant, so that the output of the first counter 176 is output. The comparison value differs depending on the length of the strobe signal.

In the above-described second embodiment, when the TPH temperature is higher than the reference temperature, the strobe signal continues to decrease the active section, and thus the heating time is shortened, thereby inducing the temperature of the TPH to be lowered. If the TPH temperature is lower than the reference temperature, the active period of the strobe signal continues to increase, resulting in a long heat generation time, leading to an increase in the temperature of the TPH. Through such control, distortion of the temperature compensation can be reduced by maintaining the TPH temperature at an appropriate temperature (reference temperature) at all times.

As described above, the video printer apparatus and the method according to the present invention can print a high-quality image by varying the heat generation period in response to the temperature change of the TPH and expressing the density of color for each gradation uniformly. The amount is reduced.

Claims (5)

A printer apparatus for introducing an image signal from a signal input source and expressing an energization factor in a thermal transfer head composed of a heating element after comparing a gray level value preset in line units with a gray level value; A memory for storing information on a heat generation time according to the temperature of the thermal transfer head; Counter means for counting a time corresponding to one fever cycle; Detecting means for detecting a temperature of the thermal transfer head; Strobe for generating information about the heat generation time corresponding to the temperature of the thermal transfer head output from the detection means in the memory, and generating a strobe signal for varying the heat generation time of the heating element in comparison with the output of the counter means A video printer device comprising a signal generator. The video printer apparatus as claimed in claim 1, wherein the strobe signal generator comprises a comparator. A printer apparatus for introducing an image signal from a signal input source and expressing an energization factor in a thermal transfer head composed of a heating element after comparing a gray level value preset in line units with a gray level value; Detecting means for detecting a temperature of the thermal transfer head; A subtractor for detecting a difference between the temperature data detected by the detection means and reference temperature data at which the thermal transfer head can operate optimally; First counter means for up / down heating time of input section data according to a predetermined control signal; A comparator outputting a control signal for up / down the state of the first counter as a result of the operation of the subtractor; Second counter means for counting a time corresponding to one heating period; And a strobe signal generator for generating a strobe signal for controlling the heat generation time of the heating element by comparing the output of the first counter means and the output of the second counter means. 4. The video printer apparatus as claimed in claim 3, wherein the strobe signal generator comprises a comparator. A printing method in which an image signal is input from a signal input source, and a conduction factor expression is performed on a thermal transfer head composed of a heating element after comparing a gray level value preset in line units with a gray level value; A detecting step of detecting a temperature of the thermal transfer head; And a temperature compensating step of generating a strobe signal representing a heat generation period and supplying the strobe signal to the thermal transfer head according to the detection result of the detecting step.