JPH0531937A - Control method of printing electric conduction of sublimation type video printer - Google Patents

Abstract

PURPOSE:To shorten a total printing period by detecting each maximum gradation number of each scanning line from printing data before each scanning line is printed and variably setting the repeated number of the electric conduction of each heating element corresponding to one line in response to the detecting values. CONSTITUTION:A thermal transfer type sublimation type video printer repeatedly conducts electricity through N heating elements corresponding to one line of a thermal head installed to a head driving section 11 on the basis of the printing data of each gradation of each scanning line regarding each three primary color of Y, M, C, and regenerates the gradation of each scanning line. An extension-number setting counter 23 and a comparator 24 for limiting transfer are annexed to such a video printer while a maximum gradation-number detecting means, etc., are added to a control processing circuit 10. Each maximum gradation number of each scanning line is detected from printing data before each scanning line is printed, the repeated number of the electric conduction of each heating element corresponding to one line is variably set to number corresponding to the maximum gradation number detected when each scanning line is printed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print energization control method for a sublimation type video printer in which each scanning line is printed by a thermal head.

[0002]

2. Description of the Related Art Conventionally, a thermal transfer type sublimation type video printer using a thermal head is disclosed in, for example, Y, M, and C as disclosed in Japanese Patent Application Laid-Open No. 2-33347 (B41J 2/36). For each primary color, the N heating elements for one line of the thermal head provided in the head driving section are repeatedly energized based on the printing data of each gradation of each scanning line to reproduce the gradation of each scanning line. ..

Next, the structure of a conventional video printer will be described with reference to FIGS. 1 and 2 corresponding to one embodiment of the present invention. As shown in FIG. 1, a video signal of a color image at the input terminal 1 is separated into a luminance signal Y and a carrier color signal C by a YC separation circuit 2, and the carrier color signal C is separated by a decoder 3 into color difference signals RY, B. Demodulated to -Y. Further, the luminance signal Y and the color difference signals RY and BY are converted into digital data by the A / D converter 4 and written in the frame memory 5 as the data of the printed image.

Then, the data in the memory 5 is read by the D / A converter 6 for analog display for monitor display.
By this conversion, the luminance signal Y and the color difference signals RY and BY are reconstructed, and the color difference signals RY and BY are modulated by the encoder 7 to reconstruct the carrier color signal C. Further, the luminance signal Y of the D / A converter 6 and the carrier color signal C of the encoder 7 are superposed and combined by the YC superposing circuit 8 to reconstruct a video signal, which is output from the output terminal 9 to the monitor C.
It is supplied to the RT or the like and the printed image of the memory 5 is displayed on the monitor.

Then, when the printing is instructed by button operation or the like,
The control processing circuit 10 of the microcomputer configuration forms the printing data of each primary color of Y, M and C from the data of the memory 5. Further, the print data of each primary color is transferred to the head drive unit 11 in scanning line units for each primary color in order to sublimate the dye of each primary color of the printing paper.

At this time, the head drive unit 11 for each primary color
Since the N heating elements for one line of the thermal head, which will be described later, are energized for each scanning line according to the print data, the print data for each primary color is set to 1 by the switching of the bus switch 12. Each scanning line is alternately transferred to and written in the first and second line memories 13 and 14, and is alternately read from both memories 13 and 14, and is transferred to the line data latch circuit 15 in line order and temporarily held. It

By the way, since each heating element of the thermal head is repeatedly energized and controlled in accordance with each gradation in each scanning line to reproduce the gradation of each primary color, the printing data of each scanning line for each primary color generates heat. It changes according to the number of gradations for each body. On the other hand, the head drive unit 11 is configured as shown in FIG. 2, and in the case of N = 512, the thermal head 16 outputs NO.
1, NO. 2, ..., NO. 511, NO. 512 N =
It is formed by providing 512 heating elements 17.

If the printing data for each heating element 17 of each gradation is D1, D2, ..., D511, D512, efficient data transfer during the printing period is performed using an inexpensive shift register or the like that is not of high speed operation type. In order to perform the above, the 512 print data D1 to D512 of each gradation of each scanning line are set to NO. D1 to D2 supplied to the heating elements 17 of 1 to 256
56 data A and NO. It is divided into data B of D257 to D512 to be supplied to the heating elements 17 of 257 to 512 and is supplied in parallel to the shift registers 18 and 19. At this time, the control processing circuit 10 synchronized with the supply of both data A and B
In response to the clock pulse CK for fetching data from, the shift registers 18 and 19 fetch and temporarily hold the data A and B, respectively.

Further, when the data A and B are taken into the shift registers 18 and 19, the latch signal L for taking in the data supplied from the control processing circuit 10 to the output latch circuit 20 is inverted and shifted to the latch circuit 20. Register 18, 1
The data A and B of 9 are simultaneously taken in, and the data D1 to D51 are output from the latch circuit 20 to the output gate 21 of each heating element 17.
Each two are supplied.

Next, from the control processing circuit 10 to the drive unit 11
When the low-active strobe signal ST for simultaneous energization supplied to the output signal ST1 is inverted to the low level, the signal ST is logically inverted by the inverter 22 and supplied to each output gate 21, and is supplied to each output gate 21 during the low level period of the strobe signal ST. The heating elements 17 are simultaneously energized in accordance with the data D1 to D512 of the latch circuit 20, and, for example, the first second gradation printing is performed. Further, during the printing of the second gradation, the data A and B of the next third gradation are taken into the shift registers 18 and 19 and temporarily held.

After the strobe signal ST is inverted to the high level, the latch signal L is inverted and the third gradation data A and B are taken into the latch circuit 20, and the strobe signal ST is next changed to the low level. When inverted, each heating element 1
7 is simultaneously energized according to the data D1 to D512 of the third gradation, and the printing of the third gradation is performed.

Thereafter, printing is performed by simultaneous energization of the fourth gradation, ... In the same manner. When printing each gradation, each heating element 17 is transferred from the control processing circuit 10 to the thermal head 16.
An energization control signal VH having a common line cycle is also supplied.

When the printing up to the set maximum gradation number is completed, the process moves to the printing of the next scanning line. Incidentally, JP-A-62-152763 (B41J3 / 2)
0) etc., the optimum energization period for each gradation differs depending on the gradation. Therefore, the energization period based on the strobe signal ST of each gradation of the second gradation, the third gradation, ... Is variably set for each gradation so that the optimum energization period is.

[0014]

In the case of the conventional sublimation type video printer, the gradation number of each scanning line is set to a prescribed maximum gradation number, for example, 128 and fixed, and is set for every scanning line. The maximum number of gradations specified above (=
128) The printing energization is repeated sequentially. Therefore, the data input (writing) and data output (reading) periods of the first and second line memories 13 and 14 and the printing period of one line have the same fixed length for every scanning line as shown in FIG. It will be a period.

Incidentally, in FIG. (M-1),
NO. m, NO. (M + 1) indicates the (m-1) th, mth, and (m + 1) th scan lines. Also, αi,
βi indicates a data input execution period and a timing adjustment standby period, αo and βo indicate a data output execution period and a timing adjustment standby period, and γ indicates a one-line printing period.

On the other hand, the actual maximum number of gradations of each primary color of each scanning line differs depending on the respective primary color densities. For example, even in the case of a maximum of 128 gradations, the maximum gradation of each scanning line has a maximum gradation. It may be less than that. Therefore, if the printing energization with the maximum number of gradations is repeated for every scanning line as in the conventional art, a large number of wasteful printing energizations in which printing is not actually performed occur and all scanning lines are scanned. The time until the printing is completed (total printing time) becomes extremely long, and there is a problem that it takes a long time from printing the command to printing.

SUMMARY OF THE INVENTION It is an object of the present invention to shorten the time from the command of printing to the printing out, thereby shortening the printing time of a sublimation type video printer.

[0018]

In order to achieve the above-mentioned object, in the printing energization control method for a sublimation type video printer of the present invention, each printing line is scanned from printing data before printing each scanning line. The maximum number of gradations is detected, and the number of times of energization of each heating element for one line of the thermal head during printing of each scanning line is variably set to a number according to the detected maximum number of gradations.

[0019]

In the printing energization control method for the sublimation type video printer of the present invention configured as described above, the number of times of energization of printing for each scanning line is the actual value of each scanning line detected from the printing data. Since it is variably set according to the maximum number of gradations, the total printing period until printing of all scanning lines is significantly shorter than before, and the time from the command of printing to the printing out. It will be significantly shorter.

[0020]

EXAMPLE One example will be described with reference to FIGS. First, FIG. 1 showing the configuration of the video printer.
The difference from the conventional method is that the gradation number setting counter 2
3, a transfer limiting comparator 24 is additionally provided, and the maximum gradation number detecting means shown in FIG. 3 is added to the control processing circuit 10.

The printing of the m-th (NO.m) scanning line will be described. The printing data of this scanning line is written in the first line memory 13 "NO.
During the period of “m data input” α i ^* , the control processing circuit 10 executes the processing of FIG.
O. The actual maximum gradation number K of the m scanning lines is obtained. That is, the nth thermal head 16 (NO.
n) the gradation number of the printing data for the heating element 17 is G
(N) and the maximum number of gradations detected is Gmax,
Initially, n = 1, Gmax = 0 and NO. Heating element 1
No. 7 is checked, and the number of bits of the print data D1 is checked. The gradation number G (1) for one heating element 17 is detected.

Then, the detected gradation numbers G (1) and Gma
x is compared, and if G (1) ≦ Gmax, Gmax is left unchanged, and if G (1)> Gmax, Gmax is changed to G (1). Next, with n = 2, NO. The gradation number G (2) for the second heating element 17 is detected, and G
(2) is compared with Gmax, and Gmax is changed to G (2) only when G (2)> Gmax.

Thereafter, each heating element 17 is set to n = 3, ..., N.
, G (N) are detected, and Gmax is set to NO. The maximum number of gradations of the scanning line of m is set, and this value is set to the maximum gradation number K.
To detect as.

Further, during the "NO.m data output" period .alpha.o ^* of the first line memory 13 of FIG. The printing data of each gradation of m is read from the memory 13 to the line data latch circuit 15 and taken into the latch circuit 15, and the detected NO. Maximum number of gradations of m scanning lines K
Is set in the counter 23. Then, “NO.
In the period γm of “m printing”, the latch circuit 15 to the comparator 24
No. transferred to the head drive unit 11 via the NO. The printing of this scanning line is executed based on the printing data of each gradation of the m scanning lines.

At this time, the printing data transferred to the head drive unit 11 is actually printed by comparing and limiting the transfer gradation number of the comparator 24 based on the maximum gradation number K of the counter 23. The gradation is limited to the Kth gradation. Also,
Based on the maximum gradation number K of the counter 23, the control processing circuit 1
0 is the period γm, which is the period required for printing from the second gradation to the Kth gradation, and the head drive unit 11 receives the clock pulse CK, the latch signal L, and the strobe signal ST necessary for printing each gradation in this period. Supply to.

Then, the periods T2, T3, ..., TK in FIG.
The heating elements 17 of the thermal head 16 are energized in accordance with the printing data of the second gradation, the third gradation, ... Printing of m scan lines is performed. In addition,
In order to perform the optimum energization of each gradation, the periods T2, T3, ..., TK based on the low level of the strobe signal ST are set so that the energization period of each heating element 17 becomes the optimum period of each gradation.
It is variably set according to the gradation by the control processing circuit 10.

Then, for each scanning line, the above-mentioned NO.
Similar to the case of m scanning lines, the thermal head 1 is detected by detecting the actual maximum gradation number K and performing the number of times corresponding to this gradation number K.
Each heating element 17 of 6 is repeatedly energized. Therefore, as is clear from FIG. 4, the printing period of each scanning line ... γ (m−2), γ (m−1), γm, γ (m +
Each of 1), ... varies in length depending on the actual maximum gradation number K, and both are periods necessary for actual printing energization.

In FIG. 4, the data input (write) and data output (read) execution periods of the first and second line memories 13 and 14 corresponding to αi and αo in FIG. 6 are fixed length periods. αi ^* (= αi), αo ^* (≧ αi
^{* And} ≤ αo) is set. Also, βim, βi
(M + 2) is the NO. m, NO.
A waiting period for timing adjustment of data input of the (m + 2) line is shown, and βo (m−1), βo (m), and βo (m
+1) is a NO. (M-1), N
O. m, NO. The standby period for adjusting the timing of the data output of the (m + 1) th line is shown, and each has a variable length.

Further, γ (m-2), γ (m-1), γ
m, γ (m + 1) is NO. (M-2), NO. (M-
1), NO. m, NO. This is the printing period of the scanning line of (m + 1), and changes in accordance with the maximum gradation number K within the range of αi ^{* to} γ. Then, in FIG. 4, in order to facilitate the comparison with the conventional example, NO. m scan line data output period αo ^* and NO. The start timing is matched with the period αi ^* of the data input of the scanning line (m + 1).

Further, NO. For the scanning line of (m-2), the maximum gradation number K is small and the actual printing period is αi.
^{* Because} it becomes shorter, waiting period γ for timing adjustment
(M−2) ^* is provided and adjusted to γ (m−2) = αi ^* . Each waiting period and Shirushiutsushi period, the execution period .alpha.i ^*, based on the maximum gradation number K, etc. .alpha.o ^* and the scanning lines, is set by the timing control of control processor 10. The circuit configuration, the maximum gradation number K detection method, and the like are not limited to those in the embodiment.

[0031]

Since the present invention is configured as described above, it has the following effects. The maximum number of gradations of each scanning line is detected, and the number of energization of each heating element for one line of the thermal head at the time of printing of each scanning line is variably set according to the detected maximum number of gradations. The number of times the lines are energized is limited to the number of times required for the actual gradation reproduction, and the total printing period until the printing of all scanning lines is completed is significantly shortened compared with the conventional method. The time until printing is greatly shortened, and the printing period of the sublimation type video printer can be shortened.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a printing energization control method for a sublimation type video printer according to the present invention.

2 is a detailed block diagram of a portion of FIG. 1. FIG.

FIG. 3 is a flowchart of maximum gradation number detection in FIG.

FIG. 4 is a timing chart for explaining the operation of FIG.

5 is a detailed timing chart of part of FIG. 4. FIG.

FIG. 6 is a timing chart for explaining the operation of the conventional example.

[Explanation of symbols]

 10 Control Processing Circuit 11 Head Drive Unit 15 Line Data Latch Circuit 16 Thermal Head 17 Heating Element 23 Gradation Number Setting Counter 24 Transfer Limiting Comparator

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 9113-2C B41J 3/20 115 D

Claims (1)

Claim: What is claimed is: 1. A printing head of a sublimation type video printer which reproduces gradation of each scanning line by repeatedly energizing each heating element for one line of a thermal head according to the printing data for each scanning line. In the image energization control method, the maximum gradation number of each scanning line is detected from the imprint data before imprinting each scanning line, and the energization of each heating element for one line is performed at the time of imprinting each scanning line. A printing energization control method for a sublimation type video printer, wherein the number of repetitions is variably set to a number corresponding to the detected maximum gradation number.