JPH03190739A - video printer equipment - Google Patents

Abstract

PURPOSE:To reduce not only the temp. difference of a thermal head between respective lines but also the density difference between the images subjected to printing output by controlling the application time of the current to the thermal head of a printing part corresponding to the count value in a counter part. CONSTITUTION:A control part 9 outputs the strobe signal of each reference time set at every density gradation from a memory part 8 on the basis of the discrimination of gradation due to a density gradation signal converting part 4 at each time when the writing of the data of each gradation in the line memory of a printing part 5 is completed. However, when the written data is the first gradation of each line, the strobe signal preset at every line on the basis of the count value of the reading line of the image data read from a memory part 3 due to a counter part 7 is added to the reference strobe time of the first gradation to output the strobe signal of the total time. On and after the second gradation, the current corresponding to image data is allowed to flow to a thermal head by the strobe signal of the reference strobe time at every gradation in each line.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video printer device, and relates to an apparatus that reduces the difference in density of a printed image between when printing is started and after printing is started.

[Prior Art] In a video printer device that prints out television images, etc. on paper, etc., first, an analog video signal such as a television image to be printed is separated into color-specific signals if the image is a color image, and then digital data is generated. (A/D conversion), the converted data for one image is stored in a memory, and the data stored in this memory is sequentially read line by line and printed out on paper or the like by a printer. Printers include, for example, impact type printers that print on paper by applying an impact force to a ribbon using a wire dot head, and non-impact type printers that print using a head that does not contact or makes soft contact with the paper, such as thermal type printers. , an inkjet type that jets ink, and an electrophotographic type that uses a laser beam or the like. In the case of a thermal printer head (soft contact type), the thermal head generates Joule heat by passing a current through a resistor, and this heat is applied to thermal paper or a thermal ink ribbon, and the coloring agent of the thermal paper is heated. Printing is performed by melting the ink to develop color (direct color development), or printing is performed by sublimating or melting the ink agent on the ink ribbon and developing color with dye ink (thermal transfer). In this way, printing is performed by generating heat by passing current through the thermal head, so in one image, the temperature of the printer head differs between the beginning of current flow, that is, the start of printing, and the time after sufficient current has flowed, that is, the end of printing. There will be a difference in temperature. If there is a difference in the temperature of the printer head, there will be a difference in the degree of sublimation or melting of the dye ink.
As a result, for example, as shown in the characteristic shown in FIG. 3, the print density of the printed image differs between the first part where data is added and the second part.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned problems, and the time for applying current based on image data on the thermal head is set to be longer than a predetermined time on the printing start line11. Thereafter, the application time is gradually shortened until it approaches a predetermined time, thereby reducing the temperature difference in the head between each line (and reducing the density difference in the printed image). .

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a video printer device that converts an analog video signal into digital data and prints it out on paper or the like via a printer section. , a memory unit that stores the digital data;
A density gradation signal converter that determines the gradation of data read from the memory section and outputs data a number of times corresponding to the number of gradations, and a thermal head etc. using a current corresponding to the data from the density gradation signal converter. A printer section that outputs a printout on paper or the like, a drive section that drives the printer section, a counter section that counts the number of read lines of data read from the memory section and outputs a signal, and a program for controlling the device. It consists of a storage unit for storing data, and a control unit for controlling the memory unit, density gradation signal conversion unit, printer unit, drive unit, counter unit, and storage unit, and controls the printer unit according to the count value in the counter unit. The present invention provides a video printer device configured to control the time of application of current to a thermal head or the like.

[Operations] As configured as above, in the video printer device according to the present invention, the time for which the current for one gradation is passed through the thermal head is made longer in the first line when print output is started, and in each subsequent line. Control is performed to gradually shorten the time during which the current flows through this one gradation aperture, thereby reducing the temperature difference in the thermal head between lines, thereby reducing the density difference in the printed image.

[Embodiment] Hereinafter, an embodiment of a video printer device according to the present invention will be described in detail based on the drawings.

FIG. 1 is a bronch diagram of a main part of an embodiment of a video printer apparatus according to the present invention. In the figure, l is a video signal processing unit that processes analog video signals such as input television images,
For example, in the case of a color image, it is separated into three colors, red, green, and blue, and output after adjusting to the required signal level. 2 is A/
The D conversion section converts the analog video signal from the video signal processing section 1 into digital image data. 3 is a memory unit that stores the digital image data from the A/D converter 2 in, for example, a DRAM (dynamic random access memory).
is written to a frame memory that can store one image using . Reference numeral 4 denotes a density gradation signal converter that determines the gradation of the digital image data read out from the memory unit 3, and converts the data of each gradation 64 times in a 64-gradation printer according to the gradation. Output. Reference numeral 5 denotes a printer unit, which has a built-in line memory that can record data for one line (for example, 480 pieces), and each gradation level read out from the memory unit 3 via the density gradation signal conversion unit 4 is stored in this line memory. Input and record the data for each gradation. Then, it is ANDed with a strobe signal (a signal for applying current to the thermal head) from the control unit 9, which will be described later, and the currents corresponding to the processed data are arranged in one line perpendicular to the image, for example. A current is applied to the plurality of heat-sensitive heads, causing a current to flow through each resistor to generate Joule heat. This heat is applied to, for example, a heat-sensitive sublimation type ink ribbon that is in contact with paper or the like, sublimates the dye ink, develops color, and prints out on paper or the like. Reference numeral 6 denotes a drive unit that feeds paper, etc. to be printed out by the printer unit 5.

A counter section 7 counts the number of read lines of image data read out from the memory section 3 and outputs a signal. 8
is a storage unit that stores programs for controlling each part of this apparatus, data of a reference strobe time set for each gradation of image data read out from the memory unit 3, and the like. Reference numeral 9 denotes a control section that controls each section of this device, adds additional strobe time data based on the count of the number of read lines from the counter section 7 to the reference strobe time from the storage section 8, and outputs a strobe signal. Output.

Next, the operation of the video printer device according to the present invention will be explained. A video signal such as a television image is input to the video signal processing unit 1 by operating a "memory" button, for example, and if this video signal is a color image, it is divided into three colors of red, green, and blue. , adjust the signal level to the required level, and convert the A/D converter 2 to the desired signal level.
Add to. The A/D converter 2 converts the input analog video signal into digital image data. This digital image data is input to the memory section 3, and is, for example, a DRA.
Write one screen worth of data to a frame memory such as M. Note that the memory in the memory section 3 is erased by the next input of image data or by a clear operation. Memory section 3
The image data stored in the image data is read line by line and input to the density gradation signal converting unit 4 in response to a command from the control unit 9 based on the operation of a "print" button or the like, for example. The density gradation signal converter 4 determines the gradation of the input image data, and according to the gradation, if the printer has 64 gradations, for example, it sequentially outputs data of each gradation 64 times. . After outputting up to 64 gradations, each data from the second line onward is sequentially read out from the memory section 3 in response to a command from the control section 9, processed in the same manner as the first line, and sequentially output. These data for each gradation are input to the printer section 5 and written into the built-in line memory. When writing of the data for the first gradation is completed, these data are ANDed with a strobe signal from the control unit 9, which will be described later.
A current corresponding to each AND-processed data is applied to the resistance element of the thermal head, and the thermal head generates heat. When the first gradation is completed, the data of the second gradation is further processed, and from then on, the process is completed up to the 64th gradation, and then the process proceeds to the second and subsequent lines, and all the lines required for one image, for example, 640 lines, are processed. , repeat these steps. The heat generated by the thermal head is
For example, it is added to a heat-sensitive sublimation type ink ribbon to sublimate dye ink to develop color and print it on paper or the like.

Each time the control section 9 finishes writing data for each gradation into the line memory of the printer section 5, the control section 9 reads the density gradation ( A strobe signal of each reference time set for each of the above 64 gradations is output. However, if the written data is the first floor exit of each line, the strobe time set in advance for each line is set to 1 based on the count value of the read line of the image data read from the memory unit 3 by the counter unit 7. It is added to the standard strobe time of the gradation, and a strobe signal of the total time is output.

For example, as shown in FIG. 2, these strobe times are, for the first line, the reference strobe time t (for example, 1 millisecond) for the first gradation stored in the storage unit 8 plus 300 microseconds, and for the second line, For example, t plus 270 microseconds for the third line, t plus 250 microseconds for the third line, etc.
In the first line, the strobe signal is long, and thereafter it is gradually shortened to approach the reference time. From the second gradation onwards, a current corresponding to the image data is caused to flow through the thermal head in response to a strobe signal having a reference strobe time for each gradation (for example, 300 microseconds for the second gradation) for each line. This is because the thermal head is warmed by the current in the first layer, so there is almost no difference in density between lines after the second layer.

The drive section 6 corresponds to each strobe time via the control section 9, and each time one line of print output is completed, the drive section 6 outputs one line.
Paper is fed through the printer section 5 line by line. The above printing operation for all lines and all gradations is performed for each color, but in the case of a color image, each data of red, green, and blue is converted to complementary colors of yellow, magenta, and cyan, and ink of each of these complementary colors is Repeat printing 3 times in order with the ribbon, 1
Outputs two print images. If it is a black and white image, printing is completed with one printing operation using a black ink ribbon.

Note that the reference strobe time stored in the storage section 8 and the strobe time for each line based on the count of the counter section 7 are set for each color of yellow, magenta, and cyan so that the tone of the printed image is appropriate. Set each at an appropriate time. FIG. 3 shows the relationship between print density and normal density, where ■ is an example of print density characteristics according to the present invention, and ■ is an example of print density characteristics when the present invention is not applied.

[Effects of the Invention] As explained above, in the video printer according to the present invention, the time for applying data to the thermal head is long at the start of printing, and the time for applying data is gradually shortened thereafter. In the printed image, the printing density is approximately equal between the first part to which the video signal is applied and the second part, and the quality of the printed image is improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a main part of an embodiment of a video printer according to the present invention, and FIGS. 2 and 3 are diagrams for explaining the operation of the video printer. In the figure, 1 is a video signal processing section, 2 is an A/D conversion ridge, 3 is a memory section, 4 is a density gradation signal conversion section, 5 is a printer section, 6 is a drive section, 7 is a counter section, and 8 is a storage section , 9 is a control section.

Claims (1)

[Claims] In a video printer device that converts an analog video signal into digital data and prints it out on paper etc. via a printer section, there is a memory section that stores the digital data, and a gradation level of the data read out from the memory section. a density gradation signal converter that determines the number of gradations and outputs data for the number of times corresponding to the number of gradations, and a printer unit that prints out a printout on paper or the like using a thermal head or the like using a current that corresponds to the data from the density gradation signal converter. and a drive section that drives the printer section;
a counter section that counts the number of read lines of data read out from the memory section and outputs a signal; a storage section that stores a program for controlling the apparatus, etc.; the memory section, a density gradation signal conversion section, a printer section; The printer comprises a control section that controls a drive section, a counter section, and a storage section, and is configured to control the application time of current to a thermal head or the like of the printer section according to the count value in the counter section. video printer equipment.