KR0138139B1 - Printer device - Google Patents

Abstract

A printer apparatus capable of compensating for variations in resistance of each of the heat generating elements (TPH) in a printer apparatus that performs energization factor expression through a heat generating head is described. The present invention relates to a printer device in which a composite image signal is input from a signal input source, and a conduction factor expression is performed on a heat generating element (TPH) composed of a heating element after preparatory gray level value and gray level comparison. A heating element correction unit is provided for compensating the heating element correction unit, and the heating element correction unit generates a constant heating energy of each resistor by the heating energy determined by multiplying the application time by the square ratio of the resistance of the heating element and the applied voltage to the deviation of each resistance. Compensation value is calculated so that the memory is stored for each gradation.

Therefore, according to the present invention, a correction is performed using a memory in which a correction value is stored for the deviation of each resistance of the TPH, so that each resistance is expressed with a constant energy for each gray level, thereby displaying a clear image.

Description

Printer device

1 is a block diagram of a conventional color video printer device.

2 is a block diagram of a color video printer device according to the present invention.

3 is a concrete diagram of the resistance maintenance shown in FIG.

4 is a detailed circuit diagram of the TPH shown in FIG.

* Explanation of symbols for the main parts of the drawings.

10 ... frame memory 20 ... color converter

30 ... γ Compensation 40 ... Resistance Compensation

50 ... line memory 60 ... system controller

70 Manufacturing counter 80 Comparison

90 ... T.P.H (Thermal Print Head)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer apparatus, and more particularly, to a printer apparatus having a heat generating element made of a resistor, and to a printer apparatus for correcting the deviation of each of the heat generating elements with a constant energy for each gray level.

Generally, a color video printer, a color copying machine, a fax (faximile), and the like are used as a device for expressing an energization factor by using a heat generating element (called a thermal print head (TPH)).

Especially. In the conventional color video printer (hereinafter referred to as CVP), as shown in FIG. 1, A / D conversion of an image signal flowing from a signal input source is stored in the frame memory 1 frame by frame.

Here, the signal input source may be a television, a video cassette recorder, a video camera, a personal computer (PC) or the like that generates a composite video signal.

In the color converter 2, data of the red (R), green (G), and blue (B) signals read out from the frame memory (1) are C (Cyan), M (Magenta), and Y (Yellow) in complementary colors. After conversion to the color signal, gamma correction is performed by the gamma correction unit 3 and stored in the line memory 4 in line units.

The comparator 7 compares the data stored in the line memory 4 with the set gradation data output from the manufacturing counter 6 under the control of the system controller 5, and then sends them to the TPH 8 for expression of energization factors. do.

Here, the TPH 8 is composed of a heating element (resistance) for generating heat when current flows to sublimate the dye attached to the ink ribbon to ignite the recording paper.

However, in an ideal case, the resistance of each heating element should be equal, but in general, each resistance has a deviation due to manufacturing problems.

That is, even if the voltage V applied to each dot DOT and the application time T are the same, the applied energy ENERGY: E

E + (V ² / R) T ... ①

As shown in the above equation, since the resistance (R) values are different, the energy generated by each resistor is also different. Therefore, even if the same time is applied to obtain the same density image, the same density is not achieved. There was a problem.

In order to overcome the above-mentioned problems, it is an object of the present invention in a printer apparatus using a heat generating element (TPH) composed of a resistor to correct a correction for the variation of each resistor at the same density using a memory in which a correction value is stored. The present invention provides a printer apparatus capable of expressing a clear image by generating heat with energy.

In order to achieve the above object, the printer apparatus according to the present invention receives an image signal from a signal input source and stores the image signal in line units and expresses the energization factor in the heating element (TPH) composed of a heating element after comparing the gray level with a predetermined gray level. In a printer apparatus that performs

And a heating element correction means for compensating for the deviation of the heating element of the TPH.

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

2 is a block diagram of a color video printer according to the present invention.

2, a frame memory 10 for storing image data in units of frames, a frame memory 10 for storing image data in units of frames, and a color converter for converting image signals into color holes for printing. (20), a gamma correction unit (30) for performing gamma correction (γ), a bottom correction unit (40) in which a correction value for compensating for the deviation of each resistance of the TPH (90) is stored, and the resistance correction unit ( The line memory 50 for storing the output of the line 40 and the data writing and reading of the frame memory 10 and the line memory 50 are controlled, and the inverse gamma correction for the gamma correction of the gamma correction unit 30 is performed. And a system controller 60 for outputting position control information for each resistor of the TPH 90 that generates heat in response to the data read from the frame memory 10 to the resistance compensator 40. Under the control of the system controller 60, a predetermined number (m) of gradation data The gradation counter 70 for outputting the gradation data of the gradation counter 70 and the data read out from the line memory 50, and the output of the comparison unit 80 in the form of a current signal. The TPH 90 is formed by printing a resistor by generating heat.

Next, the operation of FIG. 2 will be described with reference to FIGS. 3 and 4.

According to FIG. 2, a video signal flowing from a signal input source is subjected to A / D conversion and then stored in the frame memory 10 in units of frames as a digital signal.

Here, the video signal processing system for signal processing to convert the signal input from the signal input source to the A / D conversion and R, G, B form and the video display system for displaying the signal processed signal is filed by the applicant of the present applicant Korean Patent Application Nos. 91-1875 and 92-2127, so detailed description thereof will be omitted.

The image data stored in the frame memory 10 is read under the control of the system controller 60. At this time, the image data to be read is R, G, and B, and the color converter 20 has C, M, and Y having complementary colors. The color signal is converted.

Under the control of the system controller 60, the gamma correction unit 30 performs gamma correction on the Y, M, and C data output from the color converter 20, and also matches the temperature of the TPH 90 with the external temperature. In order to prevent heat storage during each gray scale display, temperature correction may be performed.

As shown in FIG. 3, the resistance compensator 40 is composed of erasable and programmable ROM (EPROM), and the position information control signal CON for each resistance of the TPH 90 output from the system controller 60 is shown. In response to this, data output from the redundancy unit 30 is inputted as an address signal, and the data for each gray level corrected according to the deviation of each resistance stored at this address are output. This EPROM can be implemented in SRAM or a look-up table (LUT).

Here, since the resistance correction unit 40 determines the deviation value of each resistance of the TPH 90 at the time of manufacture, assuming that the resistance correction coefficient is αi for each gray level m to be expressed, αi is determined for the deviation of each resistance Ri. When the corrected data is outputted, this is expressed as Di, and the output becomes αi Di.

In addition, the position control signal CON can represent the position of each resistor as n bits if the number of dots representing a line is 2 ⁿ .

That is, as shown in FIG. 4, the resistance of the TPH 90 is composed of 416 resistors and is represented by 256 gradations, and αi varies according to the deviation of 416 resistances ranging from 1 to 255 gradations. ^Since the energy must be constant with respect to the deviation of each resistance Ri of the TPH 90 according to the formula of ² / R) × T, the resistance correction coefficient αi can be calculated.

For example, when the applied voltage is 22V, the resistance is R1 = 3000 OHMS (Ω), and R2 = 3500Ω, the power of each dot is 0.1613W (Watt) and 0.138W, respectively. . At this time, when 5msec coin is used to express FULL OPTTCAL DENSITY, the energy applied to the resistor R1 is E _R1 = 0.806mJ (Joule), and the energy applied to the resistor R2 (E _R2 ) = 0.69mJ (Joule )to be.

Therefore, when the reference resistance is R2, R1 overheats. Here, about 19 mu sec is used to represent one gray level, and the energy at this time is 0.0027 mJ.

The difference in applied energy between the resistor R1 and the resistor R2 is 0.1115 mJ, and even the system is about 42 gradations. Therefore, in the EPROM of the resistance compensator 40, when an input image signal enters the binary 11111111, the resistor R2 is output as it is to the line memory 50 as 11111111, and the resistor R1 is 11010101 as a line memory. Output to 50.

In the line memory 50, data corrected from the resistance compensator 40 is written in units of lines, and the written data is output from the gradation counter 70 under the control of the system controller 60 in the comparator 80. Gray level comparison is performed with preset gray level data, i.e., 1 to 255 gray level data. When the comparison value of the comparator 80 is at a high level, the gradation data at that time is converted into a current signal form to generate heat to the TPH 90 to obtain an image of a desired gradation.

As mentioned above. The printer device according to the present invention has the effect of expressing a clear image by correcting a deviation of each resistance stored in a memory according to a correction value in a printer device using a TPH composed of resistors to express a desired gray scale.

Claims (5)

In a printer apparatus which inputs an image signal from a signal input source and expresses energization factor to a heat generating element (TPH) composed of a heating element after comparing the gray level preset in line units with the gray level. Comprising a memory for calculating the correction value and stores for each gradation so that the heating energy of each resistor provided in the TPH is kept constant, further comprising a heating element correction means for accessing the memory to compensate for the deviation of the heating element of the TPH Printer apparatus characterized in that. A video signal processor for converting a composite video signal from a signal input source into red, green, and blue signals, a video display unit for displaying a signal processed by the video signal processor, and a signal processed signal in the video signal processor. A color video printer apparatus comprising a video printer unit for performing energization factor expression on a heat generating element (TPH) composed of a heating element after comparing gray levels and preset gray values in units, The video printer unit may include a frame memory for storing data output from the video signal processor in units of frames; And TPH control means for compensating for the deviation of the heating element generated by the TPH in response to the data read out from the video printer and expressing an energization factor in the TPH. The method of claim 2, wherein the TPH control means A color converter for converting red, green, and blue signals read from the frame memory into cyan (C), magenta (M), and yellow (Y) color signals in complementary relation; Γ correction unit for performing gamma correction (γ), etc .: In order to compensate for the deviation for each resistance of the TPH, a resistance correction is stored: Line memory for storing the output of the resistance correction unit by line: Control of writing and reading the frame memory and line memory data, controlling to perform gamma correction for gamma correction of gamma correction, and position control for each resistor that generates heat in TPH in response to data read from the frame memory. A system controller for outputting information to the resistance correction unit: Gradation counter that outputs a predetermined number of m-gezo data preset under the control of the system controller: And a comparator for comparing the data read from the line memory with the gradation data of the gradation counter and outputting the data when a specific logic level signal is output to the TPH. 4. The resistance compensation unit according to claim 3, wherein the resistance correction unit corrects each of the resistors so that the heating energy is constant by the heating energy determined by multiplying the application time by the square ratio of the resistance of the heating element and the applied voltage to the deviation of each resistance. Color video printer, characterized in that consisting of the memory is stored for each gradation. The memory of claim 4, wherein a correction value is stored according to a deviation of each resistor for representing dots for each m gradation, and each resistor of the TPH output from the sound system controller corresponding to data read from the frame memory is stored. And data for each gray level corrected according to the deviation of each resistance stored at this address by inputting data output from the gamma correction unit in accordance with the position information control signal.