JPH05104755A - Image printer - Google Patents

Abstract

PURPOSE:To solve such a problem that no desired density is obtained because the wrinkles due to heat strain are generated in an ink sheet or the surface of recording paper is thermally deformed when the heating quantity of ink due to a thermal head is increased in order to obtain high density. CONSTITUTION:In the transfer of ink to recording paper 5, a control circuit 13 controlling a printer so as to perform the transfer of ink of the same color two or more times is provided and, since the quantity of the ink sublimed and transferred by performing the transfer of the ink of the same color two or more times becomes two or more times, the density of the ink becomes two or more times as compared with that due to one transfer and sufficiently high density is obtained. The density developed by one transfer may be several times smaller than the desired one and sufficient allowance can be taken with respect to the heating quantity to wrinkles or the surface deformation of recording paper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image printing apparatus for printing an image by causing a thermal head to generate heat to sublimate ink and successively transfer the ink onto recording paper.

[0002]

2. Description of the Related Art An image printer using sublimable ink realizes full-color printing by sequentially transferring yellow, magenta, and cyan inks onto recording paper. This is done by making changes. Specifically, the amount of heat applied to the ink is controlled by changing the energization time to the thermal head for each dot, and the amount of ink sublimated and transferred to the recording paper is changed, resulting in a change in density. I am letting you.

[0003]

A high maximum density leads to a wide range of gradation and is a major factor in achieving high image quality of a print image. With the conventional configuration, it is possible to obtain a high density. And when the energizing time to the thermal head is lengthened, the ink sheet itself in that part expands due to heat,
Because the amount of elongation with the part that is not heated so much in the surroundings, that is, the part that is not elongated much, becomes uneven,
There are problems that wrinkles are generated on the ink sheet and transfer is not performed well, or that the surface of the dyeing layer provided on the surface of the recording paper is deformed by heat and a desired density cannot be obtained.

The present invention solves the above-mentioned conventional problems, and provides an image printing apparatus capable of high density transfer without generation of wrinkles of an ink sheet or thermal deformation of a recording paper surface. To aim.

[0005]

In order to achieve this object, the image printing apparatus of the present invention uses an ink sheet having a thermally sublimable ink and heats according to a signal to sublimate the ink of the ink sheet for recording. A thermal head for transferring to paper, an ink sheet drive means for moving an ink sheet, a recording paper drive means for moving a recording paper, a signal to the thermal head, an ink sheet drive means, and a recording paper drive means And a control means for controlling the transfer of the ink of the same color a plurality of times in the transfer of the ink to the recording paper.

[0006]

With this configuration, since the ink is transferred to the recording paper in a state of being superposed a plurality of times, the transfer amount of the ink to the recording paper is a multiple of one time, and as a result, the maximum density is That is, a plurality of times of one transfer will be obtained. Therefore, even if the transfer density at one time is lowered, a sufficient density can be obtained after a plurality of times, so that the heat generation amount of the thermal head can be made small, and wrinkles and thermal deformation of the recording paper surface as in the past can be eliminated. It is possible.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a thermal head, 2 is an ink sheet, 3 is an ink sheet take-up reel, 4 is an ink sheet supply reel, 5 is recording paper, and 6 is recording paper 5 pressed against the thermal head 1. A platen roller 7 for performing stable transfer is a capstan roller, and the recording paper 5 is rotated by sandwiching the recording paper 5 with the pinch roller 8 to move the recording paper 5. A thermal head drive circuit 9 energizes the thermal head 1 based on a command from the control circuit 13 to generate heat. Reference numeral 10 denotes a thermal head elevating / lowering unit which elevates and lowers the thermal head 1 based on a command from the control circuit 13. Reference numeral 11 is a take-up reel driving means for rotating the ink sheet take-up reel 3. A capstan roller drive circuit 12 drives the capstan roller 7 to rotate based on a command from the control circuit 13 to move the recording paper 5. A video input terminal 14 serves as an input terminal for an image signal to be printed. 15 is a video circuit, 16
Is an A / D converter, 17 is an image memory, and 18 is an operation unit.

The operation of the image printing apparatus configured as described above will be described. The image signal input from the video input terminal 14 passes through the video circuit 15 and A / D
It is converted into a digital signal by the converter 16. Now, when the storage operation is performed at the image to be printed on the operation unit 18, the image memory 1 is sent through the control circuit 13.
A command is sent to 7, and the digital image signal is stored in the image memory 17.

Next, when a printing operation is performed by the operation section 18, a command is sent to the thermal head elevating section 10 through the control circuit 13 to raise the thermal head 1. At this point, the recording paper 5 is not in the position shown in the figure,
Most of them are located on the left side of the capstan roller 7. Here, a command is sent from the control circuit 13 to the capstan roller drive circuit 12, and the capstan roller 7
Rotate clockwise. As a result, the recording paper 5 moves to the right, and when the recording paper 5 reaches the position shown in the figure, the rotation of the capstan roller 7 stops and the recording paper 5 also stops.

Next, a command is sent again from the control circuit 13 to the thermal head elevating / lowering section 10, and the thermal head 1
Moves down and stops at the position shown. Although the transfer starts from now on, the control circuit 13 sends a command to transfer the yellow color to the thermal head drive circuit 9 based on the signal stored in the image memory 17, and the thermal head 1 is energized. The ink of the ink sheet 2 is sublimated according to the heat generated by the thermal head 1 and is transferred onto the recording paper 5. At the same time, a command is sent from the control circuit 13 to the capstan roller drive circuit 12 and the take-up reel drive circuit 11, the capstan roller 7 rotates counterclockwise, and the ink sheet take-up reel 3 rotates clockwise. The recording paper 5 and the ink sheet 2 move in accordance with the sequential transfer.

The arrangement of the ink on the ink sheet 2 is, as shown in FIG. 2, the yellow ink 2a, the magenta ink 2b, and the cyan ink 2c, which are sequentially arranged. By sequentially transferring these three colors. Full color printing is possible. Currently, the yellow ink 2a is being transferred. When the transfer of the first color is completed, the rotation of the capstan roller 7 and the ink sheet take-up reel 3 is stopped, and the recording paper 5
And the ink sheet 2 is stopped. Here, a command is sent from the control circuit 13 to the thermal head elevating unit 10, the thermal head 1 is moved up, and a command is also sent from the control circuit 13 to the capstan roller drive circuit 12 to move the capstan roller 7 in the clockwise direction. The recording paper 5 is rotated to the right, is moved to the right, and is stopped at the position shown.

Here, again, a command is sent from the control circuit 13 to the thermal head elevating / lowering section 10, and the thermal head 1 descends and stops at the position shown in the figure. Then, based on the signal stored in the image memory 17, a command for transferring magenta color is sent from the control circuit 13 to the thermal head drive circuit 9 this time, and the thermal head 1 is transferred.
Is energized, and the ink of the ink sheet 2 is sublimated according to the heat generation of the thermal head 1 and transferred to the recording paper 5. At this time, the magenta ink 2b on the ink sheet 2 is transferred. Thereafter, the same operation as described above is performed until the transfer is completed, the recording paper 5 is returned to the illustrated state, and the setting of the thermal head 1 to the illustrated state is completed.

Next, based on the signal stored in the image memory 17, a command for transferring cyan color is sent from the control circuit 13 to the thermal head drive circuit 9, and the thermal head 1 is energized. The ink of the ink sheet 2 is sublimated in accordance with the heat generated by the thermal head 1 and transferred to the recording paper 5. Thereafter, the same operation as described above is performed until the transfer is completed, the recording paper 5 is returned to the illustrated state, and the setting of the thermal head 1 to the illustrated state is completed.

Up to this point, the first transfer of the three colors of yellow, magenta, and cyan has been completed. However, the next yellow ink, magenta ink, and cyan ink of the ink sheet 2 are used to transfer the three colors of the first color. The same operation as the transfer is repeated once again, and when the transfer of the last cyan ink 2c is completed, the capstan roller 7 is rotated counterclockwise by a command from the control circuit 13 to the capstan roller drive circuit 12, and the recording paper is transferred. 5 is discharged to the left, and printing is completed.

As described above, according to this configuration, the ink of the same color is transferred twice, and the amount of the sublimated transferred ink is doubled. Therefore, the density is twice as high as one transfer. And a sufficiently high concentration can be obtained. The density produced by one transfer is almost proportional to the amount of heat applied to the ink. Therefore, if a high density is produced by one transfer, the amount of heat is increased and wrinkles are generated on the ink sheet 2 or the surface of the recording paper is heated. Although it was difficult to obtain a high density due to deformation, the density produced by one transfer is half as desired, and a sufficient margin can be provided for the heating amount against wrinkles and deformation of the recording paper surface.

In this embodiment, the transfer of yellow, magenta and cyan is repeated twice. However, as shown in FIG. 3, the ink sheet 2 has such a size that the ink portion of each color can be repeatedly transferred twice. In this case, the transfer may be performed twice for each color.

In the present embodiment, the first and second transfers are performed in the same manner. However, in this case, it is assumed that the transfer is performed once in the number of gradations of the density (for example, 64 gradations). ) And the number of density gradations after the second transfer is the same (64 gradations after the second transfer), the density at each gradation per transfer is set to half of the final density. Will be done. As another method, one having a gradation of about 1/2 or less of the final maximum density at the first transfer is displayed, and one having a gradation of about 1/2 or more of the final maximum density at the second transfer is displayed. A method of expressing is also conceivable, and this is also good. That is, all the gradation parts exceeding 1/2 of the final maximum density are the maximum gradations in the first transfer, and the gradation parts below that are transferred with a predetermined number of gradations (eg, 64 gradations). In the second transfer, the portion of the highest gradation or higher is transferred in a predetermined gradation (for example, 64 gradations). In that case, the number of gradations of the density finally obtained after the double transfer will be twice as many as the number of gradations of the single transfer, and a fine print image with more gradation can be obtained. Becomes

Further, in the present embodiment, the ink of the same color is transferred twice, but it is needless to say that the ink may be transferred a plurality of times such as three times or four times. In the above, the transfer is always performed twice, but the operation unit 18 transfers only once (high-speed printing).
Needless to say, a configuration may be adopted in which the double transfer (high density print) is selected. In addition, in this embodiment, the ink is composed of three colors, but it is needless to say that one color may be used, or four colors or the like may be used.

[0020]

As described above, according to the present invention, by causing the control means to transfer the ink of the same color a plurality of times, wrinkles of the ink sheet and thermal deformation of the surface of the recording paper do not occur, and high density ink can be obtained. It is possible to realize an excellent image printing apparatus that enables transfer.

[Brief description of drawings]

FIG. 1 is a block diagram of an image printing apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory view of a main part of an ink sheet used in the embodiment.

FIG. 3 is an explanatory view of a main part of another ink sheet used in the embodiment.

[Explanation of symbols]

 1 thermal head 2 ink sheet 3 ink sheet take-up reel 5 recording paper 6 platen roller 7 capstan roller 9 thermal head drive circuit 11 take-up reel drive circuit 12 capstan roller drive circuit 13 control circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B41J 35/16 B 7318-2C

Claims (3)

[Claims] 1. An ink sheet having a thermally sublimable ink, a thermal head for sublimating the ink of the ink sheet by transferring heat to a recording sheet by generating heat according to a signal, and an ink for moving the ink sheet. A sheet driving unit, a recording sheet driving unit that moves the recording sheet, a control unit that controls the signal to the thermal head, the ink sheet driving unit, and the recording sheet driving unit. The image printing apparatus is characterized in that the means controls the transfer of the ink of the same color a plurality of times during the transfer of the ink onto the recording paper. 2. An operation of sequentially transferring the inks of a plurality of colors onto a recording paper using an ink sheet in which sublimable inks of a predetermined plurality of colors (for example, yellow, magenta, cyan) are sequentially arranged, and then this operation is performed. 2. The image printing apparatus according to claim 1, wherein the control means controls the same operation to be performed again on the same recording paper. 3. An ink sheet arranged so that sublimable inks of respective colors (for example, yellow, magenta, and cyan) can be successively transferred to the recording paper a plurality of times, and the inks of the respective colors are sequentially transferred to the recording paper a plurality of times. 2. The image printing apparatus according to claim 1, wherein the control means controls so as to perform the operation.