JPH06286200A - Thermal sublimation type recorder - Google Patents

Abstract

PURPOSE:To provide a thermal sublimation type recorder in which a high maximum density can be set, and stable image quality of a black level is printed without deteriorating a printed state of a print sheet. CONSTITUTION:A thermal sublimation type recorder 20 is constructed to color- print by generating heat from a heat generator of a thermal line head 21 in response to image data of information source, sequentially sublimating dye circularly coating in a prescribed order and transferring it to a record sheet 22. When the sheet 22 in A6 size and the head having 512 pixels (6 dots/mm) are used, a margin of 27 pixels at maximum can be formed. A color regulating pattern 22b is printed on a color regulating pattern 22a of the margin, the pattern 22b immediately after printing is emitted from a white light source 23, converted to an electric signal via a photoreceiver 26 though a color filter 25, its reflection density is measured to decide whether it is the maximum density or not, and printing density is regulated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive sublimation recording apparatus for color-printing a television image or the like in high definition.

[0002]

2. Description of the Related Art Conventionally, images from a personal computer, a camera-integrated video tape recorder, an electronic still camera, and the like have been soft-copied by a display device or the like capable of displaying high resolution. However, in recent years, a color printing apparatus has been developed that is capable of displaying images of these information sources as a full-color, high-definition hard copy. In the color printing apparatus, for example, a dye in which three colors of yellow, cyan, and magenta are cyclically applied in a predetermined order is subjected to sublimation transfer of three colors one by one by a thermal head that generates heat in accordance with a video signal of an information source. Thus, the one-screen color printing on the recording paper is completed.

By controlling the time width of current applied to the thermal head, the amount of dye sublimated is adjusted so that gradation can be performed.

As shown in FIG. 3, the image data 2 of the information source input to the thermal sublimation type recording apparatus 1 is first subjected to color correction / level correction for correction of the color mixture component of the ink used and gradation density characteristics. It is supplied to the tone correction means 3. In the color correction / gradation correction unit 3, the gradation characteristics are corrected by the supplied image data 2 and the data of the look-up table provided in the printer control circuit 4.

Next, the image signal corrected by the color correction / gradation correction means 3 is transferred to the line memory 5 as an image signal for each line corresponding to the thermal line head. Then, the image signal stored in the line memory 5 is transferred to the parallel / serial conversion circuit 6, converted into a single data string, and output to the data comparison circuit 7 pixel by pixel.

Here, the data for each pixel output from the parallel / serial conversion circuit 6 to the data comparison circuit 7 is, for example, 0 to 255 if the image data output from the gradation counter 8 is 8 bits. The energizing pulse corresponding to the number of gradations is selected in comparison with the colors up to and the energizing pulse is output to the shift register 10 of the thermal line head 9 as heat generation data. Since the heat generation data output from the data comparison circuit 7 is sequentially input to the shift register 10, the heat generation data is once fixed to the latch circuit 11 and then output to the gate circuit 12. The gate circuit 1
2, the heating element 13 is energized for a time pulse corresponding to the heating data input to the gate circuit 12 to print a predetermined density on the recording paper.

In order to perform high-speed processing, the shift register 10 stores, for example, 128 lines of image data for one line.
The data is divided into pixel units and input as parallel heat generation data. In addition, the heating element 13
Prints data corresponding to the heat generation data fixed in the latch circuit 11 while the heat generation data is being sent from the data comparison circuit 7 to the shift register 10.

However, as shown in FIG. 4, the relationship between the energization time for energizing the heating element 13 of the thermal line head 9 and the print density is that the substrate temperature of the thermal line head 9 is 30 ° C. even when the energization time is the same. The print density also changes at 40 ° C. and 50 ° C. Further, as shown in FIG. 5, even when printing yellow, magenta, and cyan sequentially, the surface temperature of the thermal line head 9 becomes higher when printing magenta than when printing yellow,
Since the temperature when printing cyan becomes even higher than when printing magenta, the substrate surface temperature gradually rises corresponding to the surface temperature of the heating element 13 of the thermal line head 9.

Therefore, as shown in FIG. 3, the heating element 1
The temperature detecting means 14 for detecting the substrate temperature of No. 3 was provided. Then, the temperature data detected by the temperature detecting means 14 is input to the printer control circuit 4, compared with the environmental temperature data group, and appropriate gradation data is extracted and output to the strobe pulse generation circuit 15. Further, the strobe pulse generation circuit 15 responds to changes in the substrate temperature, and outputs a control signal, which sets an energization time suitable for the surface temperature of the heating element 13, to the gate circuit 12 for printing to correct the printing density. Was going to do.

[0010]

However, in the method of detecting the substrate surface temperature of the thermal line head to control the energization time to the heating element to perform the density correction, the surface temperature of the heating element and the substrate Due to the large temperature difference from the surface temperature, the concentration could not be sufficiently stabilized. For this reason, when printing the same screen a plurality of times, there is a problem in that a high density portion (black portion) varies and the print screen becomes rough due to excessive heat, resulting in a poor-looking print state. Had occurred.

Further, since the maximum density cannot be set high, an unclear image having an unstable black level and an unclear contrast is obtained, so that the user cannot be satisfied with the image quality.

The present invention has been made in view of the above circumstances, and provides a thermal sublimation type recording apparatus capable of setting a maximum density high and performing stable printing at a black level without deteriorating the printing condition of a printing screen. Is intended.

[0013]

A thermal sublimation recording apparatus according to the present invention changes the sublimation transition amount of a dye applied to an ink sheet by controlling a current pulse applied to a heating element of a thermal line head. In a thermal sublimation recording apparatus that performs gradation recording on recording paper, a color adjustment pattern printed on the empty portion of the recording paper with color adjustment data,
A white light source that irradiates a color adjustment pattern immediately after printing, a color filter that transmits the reflected light of the white light source that irradiates the color adjustment pattern, and a light receiving element that converts the reflected light that has passed through this color filter into an electrical signal. And a printer control circuit for determining the density based on the electric signal converted by the light receiving element and supplying the density adjustment information from the determination result.

[0014]

With this configuration, first, the color adjustment pattern based on the color adjustment data is printed on the empty portion of the recording paper. Next, a white light source is irradiated on the printed color adjustment pattern. At this time,
The light from the white light source is reflected by the color adjustment pattern and transmitted through the color filter. Then, the light passing through the color filter is converted into an electric signal by the light receiving element, while the reflection density is judged to control the current imprinting time to the thermal head.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 relate to an embodiment of the present invention, and FIG. 1 is a block diagram illustrating gradation control of a thermal sublimation recording apparatus,
FIG. 2 is an explanatory diagram showing a schematic configuration of the thermal sublimation recording apparatus.

As shown in FIG. 2, the thermal sublimation type recording apparatus 20.
Causes the heating element of the thermal line head 21 to generate heat in response to the video signal of the information source, and sublimates dyes that are cyclically applied to an ink sheet (not shown) in the order of, for example, yellow, magenta, and cyan. Then, the color printing is performed by transferring the recording paper 22 to the recording paper 22. That is, first, a yellow dye is sublimated and transferred onto the recording paper 22 for printing. Then, a magenta dye is sublimated and transferred onto the recording paper 22 on which the yellow color has been printed, and the magenta dye is superimposed and printed. Finally, the recording paper 2 on which the yellow and magenta are printed
Color printing is completed by superimposing a cyan dye on 2 and sublimation transfer.

At this time, for example, the photographic printing paper 22 is A6 paper and the thermal line head 21 has 512 pixels (6 dots /
mm) is used, the number of scanning lines of the NTSC signal is 525, while the number of scanning lines is 4 during the vertical recovery period.
Since 0 lines are used, a maximum of 2 obtained by subtracting 485 scanning lines from the 512 pixels of the thermal line head
A blank portion of 7 pixels can be formed on the photographic printing paper 22.
In the present invention, the blank portion of the printing paper 22 is used as the color adjustment pattern portion 22a, and the color adjustment pattern is printed here to detect the maximum density of the desired color and perform color correction. I am able to do it.

The thermal sublimation type recording apparatus 20 includes:
A white light source 23 for irradiating the color adjustment pattern portion 22a, a condenser lens 24 for condensing the reflected light, a color filter 25 for transmitting the condensed light, and a light transmitted through the color filter 25 is converted into an electric signal. The respective light receiving elements 26 are provided on the optical axis.

That is, as shown in FIG.
The image data 31 of the information source recorded in the B frame memory or the like is the image / color adjustment data switching circuit 32.
Input to the color adjustment pattern portion 22a of the recording paper 22.
The image data 31 is switched so that the color adjustment pattern 22b can be printed.

Next, the image signal generated by the image / color adjustment data switching circuit 32 is supplied to the color correction / gradation correction means 33 for correcting the color mixture component of the used ink and the gradation density characteristic. To be done. In the color correction / gradation correction means 33, the supplied image signal and the printer control circuit 3
The gradation characteristic is corrected by comparing with the data of the lookup table of No. 4. The image signal generated by the color correction / gradation correction means 33 is the thermal line head 2
An image signal for each one vertical (or one horizontal) line corresponding to 1 is transferred to the line memory 35. The image signals transferred to and stored in the line memory 35 are
The data is converted into a single data string by the serial conversion circuit 36 and then output to the data comparison circuit 37 pixel by pixel.

Next, the data for each pixel output to the data comparison circuit 37 is compared with the number of gradations stored in the printer control circuit 34, and the energizing pulse corresponding to the pixel is supplied to the gradation counter 38. As heat generation data from the shift register 3 of the thermal line head 21
9 is output. In order to process the heat generation data output from the data comparison circuit 37 at high speed, the shift register 39 divides, for example, one line of image data into 128 pixel units or the like and inputs them as parallel heat generation data. Then, the heat generation data input to the shift register 39 is once fixed to the latch circuit 40 and then output to the gate circuit 41. In the gate circuit 41, the energization time is controlled so that the heating element 42 of the thermal line head 21 generates heat for a time width corresponding to the heat generation data input to the gate circuit 41. When a current having a predetermined time width is applied to the thermal line head 21, the heating element 42 generates heat and prints on the recording paper 22 with a predetermined density.

That is, the recording paper 22 is printed in color by sequentially printing yellow, magenta, and cyan. At this time, first, the highest density yellow dye, which is the first color, is printed on the color adjustment pattern portion 22a of the recording paper 22. Next, magenta with the highest density, which is the second color, is printed on the portion where the highest density yellow is printed. The color adjustment pattern portion 22a of the recording paper is in a state in which a red color having a red reflection characteristic is printed by superimposing the maximum density yellow and the maximum density magenta. Finally, the third color, the highest density cyan, is printed on the portion printed in red. The color adjustment pattern portion 2
By superimposing the highest density cyan on the red-printed portion of 2a, black having a black reflection characteristic is printed.

Further, since the color adjustment pattern portion 22a, which is sequentially superimposed as described above, is illuminated by the white light source 23, the color adjustment pattern portion 22a emits the first color yellow and the second color yellow. Since the reflected light having the reflection characteristics of red in which the color is superimposed and black in which the third color is superimposed on the red is reflected, the reflected light is collected by the lens 24 and passed through the desired color filter 25. As a result, light having a desired wavelength can be extracted.

For example, while yellow is being printed, a blue filter 25b, which is a complementary color of yellow, is provided to transmit reflected light, so that light of a yellow wavelength can be extracted. If the magenta color is being printed, the color adjustment pattern portion 22a is red, so that a cyan filter 25c, which is a complementary color of red, is provided to transmit the reflected light, and It is possible to extract light of the wavelength.

From this, as shown in FIG. 1, the yellow, red, and red color filters 25 of desired colors are arranged and taken out.
Light having a reflection characteristic such as black is converted into an electric signal by the light receiving element 26, amplified by the amplifier 27, converted into a digital signal by the analog / digital conversion circuit 28, and input to the printer control circuit 34. There is.
The electric signal obtained by converting the reflection characteristics of each color is judged by the printer control circuit 34 as to whether or not the reflection density is the highest. When the printer control circuit 34 determines that the reflection density exceeds the maximum value, the strobe pulse generating circuit 44 causes the thermal line head 21 to detect the temperature and the reflection density of the heating element 42 detected by the temperature detecting means 43. The print density is adjusted by transmitting a control signal for shortening the energization time to the heating element 42.

As described above, in the thermal sublimation type recording apparatus 20 of the present embodiment, the margin portion of the recording paper 22 is subjected to the color adjustment pattern portion 2.
2a, the color adjustment pattern portion 22a is subjected to color adjustment printing, and the color adjustment pattern portion 22a immediately after printing is irradiated with the white light source 23.
By receiving the reflected light of No. 3 by the light receiving element 26 through the filter 25, the maximum density of each color of yellow, red, and black immediately after printing can be measured and more appropriate correction can be performed.

Further, since it is possible to always print with the maximum density of each color, the black level of the image is stable, and images with clear contrast can be continuously printed.

Further, it is possible to print with a higher maximum density, and when the measured reflection density value exceeds the maximum density value, the maximum density can be changed by shortening the energization time to the thermal line head 21. Since the printing is performed without the need, the temperature of the thermal line head 21 can be prevented from increasing more than necessary.

Therefore, since the temperature of the thermal line head 21 does not rise more than necessary, the heat of the photographic printing paper 22 is not excessively applied, so that the surface condition of the photographic printing paper 22 is always improved.

In the measurement of the reflection density, three kinds of the color filters 25 and the light receiving elements 26 are prepared and combined to obtain an electric signal, and three kinds of only the color filters 25 are prepared and sequentially switched. There are ways.

When it is determined that the reflection density of the electric signal input to the printer control circuit 34 exceeds the set value, the density adjustment on the recording paper 22 is performed by, for example, the count number of the gradation counter 38. The density can be adjusted by subtracting the ratio, and the set time of the strobe pulse determined according to the value of the gradation counter 38 is 95%, 90%, 85%, etc. The density is adjusted by subtracting with.

Further, due to the difference in the chemical composition of the sublimation dye, there is also a subtle difference in the maximum reproducible densities of the respective colors of yellow, magenta and cyan, so that the setting data of the maximum densities of the respective colors are slightly changed.

[0033]

As described above, according to the present invention, it is possible to provide a thermal sublimation type recording apparatus capable of printing a stable black level image quality without deteriorating the printing condition of the printing screen by setting the maximum density high. it can.

[Brief description of drawings]

1 and 2 relate to an embodiment of the present invention.
Is a block diagram illustrating gradation control of a thermal sublimation type recording apparatus.

FIG. 2 is an explanatory diagram showing a schematic configuration of a thermal sublimation type recording apparatus.

3 to 5 are related to a conventional example, and FIG. 3 is a block diagram illustrating gradation control of a thermal sublimation recording apparatus.

FIG. 4 is a diagram showing a relationship between a temperature of a heating element of a thermal head, an energization time width and a concentration.

FIG. 5 is a diagram showing a relationship between a temperature of a heating element of a thermal head and a color, and a change with time of a temperature of the heating element of the thermal head and a substrate surface temperature.

[Explanation of Codes] 20 ... Thermal sublimation type recording device 21 ... Thermal line head 22a ... Color adjustment pattern portion 22b ... Color adjustment pattern 23 ... White light source 25 ... Color filter 26 ... Light receiving element 34 ... Printer control circuit 42 ... Heat generation body

Claims (1)

[Claims] 1. A thermal sublimation recording apparatus for gradation recording on a recording paper by changing a sublimation transfer amount of a dye applied to an ink sheet by controlling a current pulse applied to a heating element of a thermal line head. , A color adjustment pattern that is printed by the color adjustment data on a vacant part of the recording paper, a white light source that irradiates the color adjustment pattern immediately after printing, and a reflected light of the white light source that irradiates the color adjustment pattern is transmitted. A color filter, a light-receiving element that converts the reflected light that has passed through the color filter into an electric signal, a printer control circuit that determines the density based on the electric signal converted by the light-receiving element, and supplies density adjustment information from the result of the determination. A heat-sensitive sublimation recording device comprising: