JPS60147361A - Recording correction of thermal transfer type color printer - Google Patents

Abstract

PURPOSE:To make it possible to obtain high quality color print and to enhance the efficiency of recording energy, with due regard to the past recording number of times, by controlling electric energy applied to the corresponding heat generation element of a thermal head used in recording this time. CONSTITUTION:A control circuit 4b has two line buffers 11a, 11b, a recording number operator 12 and an image signal operator 13 while a control circuit 4c has three line buffers 14a, 14b, 14c, a recording number operator 12 and an image signal operator 13. The recording number operators 12 of the control circuits 4b, 4c calculate the recording number of times of this time recording to the position of each picture element and output the calculated result to the image signal operators 13 as information for determining the width of a recording pulse. Because electric energy applied to a heat generation element for the purpose of this time recording to the position of the previous picture element is controlled on the basis of said calculation, good quality color print can be always obtained and energy efficiency can be enhanced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses at least one thermal head having a plurality of heating elements to perform multiple recordings on recording paper by superimposing them in different colors. The present invention relates to a recording correction method for a thermal transfer color printer.

[Prior art]

2. Description of the Related Art Conventionally, a thermal transfer color printer using a plurality of thermal heads has been used, for example, as shown in the schematic diagram of FIG. That is, with respect to the recording paper 1 running from left to right in the figure, three thermal heads 2a, 2 are placed at a predetermined distance from each other along the running direction of the recording paper 10.
b and 2C, and the first thermal head 2a
is brought into sliding contact with the recording paper 1 via an ink donor film 3 & capable of transferring yellow ink onto the recording paper 1, and the thermal head 2b of the second tube is capable of transferring magenta ink onto the recording paper 1. The third thermal head 2c is brought into sliding contact with the recording paper 1 via the ink donor film 3b, and the third thermal head 2c is brought into sliding contact with the recording paper IK via the ink donor film 3@ capable of transferring cyan ink onto the recording paper i. It has a similar configuration. Note that 4m+4b and 4c are control circuits for each of the thermal heads 2m, 2ti, and 20.

Thermal head 2m + 2b and 2c has recording paper 1
1 to correspond to the number of pixels in the main scanning direction! ! i! number of heating elements (for example, the number of heating elements required when recording image information on Japanese Industrial Standards A column 4 recording paper is 172)
(2048 pieces in the case of the recording paper number 4 in column B), and the recording paper l By applying electrical energy and generating heat in synchronization with the running of
Color printing is performed by sequentially superimposing and transferring three colors of ink: , magenta, and cyan.

By using multiple thermal heads like this,
When recording multiple times on the recording paper l with different colors superimposed on each other, when looking at one pixel position on the recording paper l, the pixel position where the ink is transferred by penetrating the wall multiple times is The state of the recording paper l differs depending on the number of times of recording. For example, at a pixel position where recording was performed by the heating element of the first thermal head 21, the smoothness of the recording paper l is improved compared to an area where no recording was performed. When the same electrical energy as that applied to the heating element of the first thermal head 2a is applied to the corresponding heating element of the second thermal head 2b in order to perform the second recording in a superimposed manner,
The transfer range expanded and the image quality deteriorated, resulting in a drawback that the print quality deteriorated. This phenomenon is noticeable when the third recording is performed at the same pixel position.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a recording correction method that enables the production of high-quality color prints and improves recording energy efficiency.

[Structure of the invention]

Therefore, in this invention, the electrical energy applied to the corresponding heating element of the do is transferred to the thermal used for rounding the current recording, taking into account the number of recordings made in the past for the pixel position to be recorded this time. The above objectives are achieved through control.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A recording correction method for a thermal transfer type printer according to the present invention will be described in detail below with reference to embodiments shown in the accompanying drawings.

FIG. 2 shows a schematic diagram of a thermal transfer type color printer to which the recording correction method according to the invention is applied, and parts corresponding to those in FIG. Although omitted, in the case of FIG. 2, only yellow image information is given to the control circuit 4a for the first thermal head 2a, as in the case of FIG. The control circuit 4b for 2b is supplied with not only black and magenta image information but also yellow image information.

Further, the control circuit 4c for the 3rd vi'th thermal head is supplied with image information of three colors: yellow, magenta, and cyan.

FIG. 3 shows the recording state of pixels D1 to D1 recorded by the heating elements of each thermal head 2m, 2b, and 2C. Z b and 2c scan lines are shown, and the scan line L1 moves to the scan line Lb as the recording paper l travels, and then the scan line Lc
This shows a state in which superimposed recording is performed by moving 1jc.

Note that the number within each pixel indicates the number of recordings at that pixel position.

Now, regarding the pixel D1, the first recording in yellow is performed in the scanning line L, and then the second recording in cyan is performed in the scanning line L0. Also, if we look at the pixel DsllC, the first recording of yellow is done on the scanning line L,
A second printing is performed using magenta on the scanning line Lb, and a third printing using cyan is performed on the scanning line L0. Further, regarding the pixel D3, it is shown that the first recording is performed for the first time on the scanning line Le. Here, regarding recording by the thermal head 2b on the scanning line Lb, the electric energy applied to each heating element is
Is it the first recording like I, or is it pixel D!
and D7, which differ depending on whether it is the second record. That is, in the second recording,
5-30 for the first record. Electrical energy as small as ts is applied to the heating element. Similarly, regarding the recording by the thermal head 2C on the scanning line Le, whether the recording is the first recording like the pixels D3 and Ds, the second recording like the pixels D1 and Ds, or The electric energy applied to the heating element is varied depending on whether it is the third recording, such as pixels DI and Dl.

In Jin's embodiment, the recording voltage 9 applied to each heating element is
The stain energy is controlled by increasing/decreasing the /4 lus width of the lus. For example, the thermal heads 2m, 2b and 2c are each a thick film type thermal head equipped with a heating element of 8 dots/wi, and the ink donor film 3
a r 3 b and 3c are yellow with a melting point of 63°C;
In the case of an ink layer including magenta and cyan ink layers, the suitable recording width for the first recording is set at 1.25 mg@a, but the width for the second recording is 1.25 mg@a. Nodame's pulse width was 1.1m 1lee, and the third record Nodame's pulse width was 1.0m5aa.
That's fine.

FIG. 4 shows a control circuit constructed based on the recording correction method described above.

In FIG. 4, the control circuit 4b includes two line buffers l1m and llb, a recording number calculation unit 12, and an image signal calculation unit 13. The control circuit 4c also includes three line buffers 14m, 14b and 14.times., a recording number calculation unit 12, and an image signal 2 calculation unit 13. Line buffer l1m.

11b and 14-14a to each thermal.

The line buffer l1m of the control circuit 4b has a storage area corresponding to the total number of heating elements (total number of dots) of the cards 2a to 2c.

Image information for one line corresponding to scanning line L recorded in mode 2a is stored, and image information for one line corresponding to scanning line Lb to be recorded this time in mode 2b is stored in line buffer llb. to remember. Further, the line buffers 14m and 14b of the control circuit 4C are made to store one line of image information corresponding to the scanning lines L and Lb recorded by the first and second thermal heads 2a and 2b, respectively, Line buffer 14 (+ has
Image information for one line corresponding to the scan line L0 to be recorded this time is stored by the thermal head 2C. Each control circuit 4b
The recording number calculation unit 12 of 4C calculates how many times the current recording is for each pixel position, and records the calculation result.) The image signal calculation unit 13 uses information for determining the pulse width. Output to.

Now, if we look at the image signal calculator 13 of the control circuit 4C,
The image signal calculator 13 receives the recording number information T from the recording number calculator 12 and also inputs the line buffer γ.
14a, image information of the scanning line L0 to be recorded this time is input. When recording one line, the image signal calculator 13
First, the image information from the line buffer 14a is output as is. Output to. Next, the image signal calculator 13 extracts pixel positions whose number of recordings is the second or lower, based on the recording number information T inputted from the recording number calculator 12, and sets only that pixel position as a logical value "1". Output ■. Output to.

Next, the image signal calculator 13 extracts only the pixel position recorded the first time based on the recording number information T0, and outputs only that pixel position as the logical value "l" to the output ve.

FIG. 5 shows an example of the overall configuration of the thermal head.

In Fig. 5, a plurality of heating elements RI+R1...Rn
Each has a rectifying diode m11 ml...m
Power is supplied to the terminal E through n to generate heat in each heating element. In addition, each heating element R1+ J...R
The other ends of n are connected to the output terminals of Nant gates GI, G, . . . , Gn, respectively. These Nantes Gate G,
l G,...Gn are, for example, oven collector type, and each dart G! +G Note: Operates to draw the recording current applied from terminal E to each heating element only when the AND condition of Gn is satisfied.

The internal configuration of the control circuit 4c is as shown in FIG.
Output■. Then, the image information v0 in the order described above is output to the shift register 20. The shift register 20 is a serial input/parallel output shift register, and performs the operation of shifting the serially input image information vc to a predetermined bit position at which each resistor is to be heated based on an appropriate transport lock. After a predetermined shift operation is performed by the shift register 20, this image information is temporarily held in the buffer 21. This buffer 21 holds the previous image information during the shift operation by the shift register 20, and stores each 5') G
t#Gt...Adding to Gn prevents each heating resistor from dissipating heat during the interval between recording and pulse application. The recording pulse application circuit 22 is connected to each group)
Gn... Performs an operation to variably control the recording pulse width applied to Gn. The variable control first outputs a pulse with the shortest pulse width of 1.0ms@e, then outputs a pulse with a pulse width of 0.
．． Output additional pulse of 1m5ec, then 0.15rr
This is a control that adds H and C, and outputs the pulse.

Next, a specific example of the operation of the apparatus shown in FIG. M5 will be explained with reference to the time chart shown in FIG. Figure 6 is a record/4
'The pulse applying circuit 22 outputs each ?? It shows the russ.

When recording one scanning line, the control circuit 4c first sends all the heating resistors to be recorded this time (wjJ element DS r Dg + Ds * on the scanning line L0 in FIG. 3).
DB 1 (corresponding to DB and D7) only as a logical value “
The image information vc1, that is, the image information of the scan line L0 to be recorded this time, is sequentially input to the shift register 20JC. Hereinafter, this will be referred to as first picture information.

The shift register 2o appropriately shifts this to a predetermined bit position, and then transfers this first image information to the buffer 21. The buffer 21 inputs this first image information r information in parallel to the signal F (x s + G!...). Along with this input, the recording/f pulse applying circuit 22 outputs the shortest recording pulse width. A record/base with 1.0 mmec is added to each ?-) (see Figure 7(,)). As a result, only all the heating resistors corresponding to the first image information are energized for 1.0 m5ec.

Next, the first image information is transferred from the shift register 2o to the i4 buffer 21, and at the same time, the next second image information is transferred to the shift register 20/Cl-corporate. This second image information is obtained by extracting image information to which a recording pulse width of 1.1 m5ec or more should be added from the first image information, and setting only this extracted information □ to a logical value "lj". After this second image information is transferred to the buffer 21 in the same manner as described above, it is input to each gate G, , G, . . . Gn.

Along with this input, the recording pulse application circuit 22 outputs 0
．． A pulse having a recording pulse width of 1 m5 ec is input to each dart (see FIG. 6(b)). As a result, the heating resistor corresponding to the 2'th information (corresponding to the pixel D!t Ds r DB Oyohi Ds K on the scanning line L0 in FIG. 3) is 1.1 m5ec.
(1,0+0.1) The operation of the control circuit 4e, shift register 20, buffer 21, and recording pulse application circuit 22 is appropriately synchronized. Of course, it is annoying that the next record number is added before heat dissipation begins.

The third image information outputted from the control circuit '4 and the shift register 5 and 20. buffer 2
1 to each dart. This third image information is obtained by extracting image information to which a recording pulse width of 1.25 m'sec should be added from the second image information, and using the extracted □
Only the logical value rx is taken as nine-dimensional image information. This secretion 3'ii! When the i7 information is input to each group)
ec O additional pulse is output (see Figure 7 (,))
. Therefore, the heating resistor (third
Pixel D in the figure! and □ru corresponding to Ds result in 1.25 m5ec (1', ”, 1 move 0
．． 15) It will be energized.

In addition, in this example, the cicada performs recording i by variable control of the pulse width (energization time) of the i self-record/main pulse applied to the heat generating element, for example, a high frequency pulse is applied to each heating element. However, the deity of this high frequency/f pulse may be changed. Further, the applied voltage may be variably controlled. The key is to variably control the electrical energy applied to each heating element.

Furthermore, although this embodiment is a case of a thermal transfer plate color printer using a so-called one-pass method using a plurality of thermal heads, the present invention uses a so-called multi-pass method using a single thermal head. It can also be applied to thermal transfer plate color printers. In this case, the ink donor film has a first part that can transfer, for example, yellow ink onto the recording paper and a second part that can transfer magenta ink.
A single film having a part and a third part to which cyan ink can be transferred. First, a yellow image is recorded while the recording paper is running with the first part superimposed on the recording paper. Then, return the recording paper to its original position, run the recording paper with the second portion superimposed on the recording paper, and record the magenta image superimposed on the yellow image while performing the above-mentioned correction, Further, the recording paper may be run with the third portion superimposed on the recording paper, and the cyan image may be recorded superimposed on the yellow image and the magenta image while performing the above-described correction.

〔Effect of the invention〕

As explained above, according to the recording correction method for a thermal transfer color printer according to the present invention, the number of recording times for the pixel position on the recording paper is calculated from the current and past recording information for the pixel position to be recorded this time. Since the electric energy applied to the heating element for the current recording for the pixel position is controlled based on this calculation, high-quality color prints can always be obtained. Furthermore, since the electrical energy for the second and third recordings is reduced compared to the first recording, energy efficiency can be improved. It goes without saying that the recording correction method and apparatus according to the present invention can be applied not only to color printers but also to copying machines.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a conventional thermal transfer color printer, Fig. 2 is a schematic diagram of a thermal transfer color printer to which the recording correction method according to the present invention is applied, and Fig. 3 shows the recording state of pixels on recording paper. FIG. 4 is a block diagram showing an apparatus according to an embodiment of the invention, and FIG. 5 is a diagram showing a thermal system according to an embodiment of the invention. FIG. 6 is a time chart for explaining the operation of FIG. 5. 1... paper e, 2 m + 2 by 2 e...
・Thermal head, 3ay3b+351... Ink donor film, 4 m, 4 b, 4 e-...
Control circuit, 11m+11b+14m 114b
r 14 e... Line buffer, 12... Recording number calculator, 13... Image signal calculator, 2o... Shift register, 21... Buffer, 22... Recording nozzle application circuit . 6th m (C)-11111” ■

Claims (2)

[Claims] (1) Using at least one thermal head having a plurality of heating elements activated by electric energy corresponding to each pixel position on the recording paper, multiple recordings are performed on the recording paper at different times. In the recording correction method of 2-Norinta, which is a thermal transfer type that performs color superimposition, the number of times of recording for the pixel position is determined from the current and past recording information for the pixel position to be recorded this time on the recording paper souvenir. A recording correction method for a thermal transfer color printer, characterized in that the electric energy applied to a corresponding heating element for the current recording at the pixel position is controlled based on the calculation. (2) The electrical energy is applied to each of the heating elements. Claim 1 (1) characterized in that the method is controlled by increasing or decreasing the width of the recording/gusus/brachia to be applied.
) Recording correction method for a thermal transfer color printer.