JPS6338315B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a thermal recording device.

In a transfer-type thermal recording device, image information is recorded by applying a heat pulse from the thermal recording medium side with the thermal recording medium and recording paper stacked on top of each other.

FIG. 1 shows the cross-sectional structure of a conventionally used thermal recording medium. The thermal recording medium 1 is composed of a thin base paper 1A made of capacitor paper or the like, and a thermally transferable ink layer 1B coated on one side of the thin base paper 1A. The thermally transferable ink layer 1B is made of ink that is fluidized or sublimated by heating. Such a thermal recording medium is also called an ink donor sheet.

To perform two-color recording using ink donor sheets, two types of ink donor sheets that perform recording in different recording colors and two thermal heads that apply heat pulses to these sheets are prepared. Then, the recording paper (plain paper) is first superimposed on the ink donor sheet on which recording is to be performed, and is passed directly above the heating element of the thermal head provided correspondingly. Due to the selective transfer of ink, recording in the first recording color is thereby performed. Next, after separating the recording paper from this ink donor sheet, it is overlapped with an ink donor sheet for the next recording color,
It passes directly above the heating element of the thermal head provided correspondingly. As a result, recording is performed in the next recording color.

If two-color recording is to be performed using this type of ink donor sheet, two sets of thermal heads are required. Therefore, two sets of drive circuits and the like are required for each of these heads, resulting in the disadvantage that the apparatus becomes expensive and large.

In contrast, FIG. 2 shows the cross-sectional structure of a conventionally used thermal recording medium capable of recording on two sheets at the same time. The thermal recording medium 2 has a thermally transferable ink layer 1B formed on one side of a base paper 1A, and a thermosensitive layer 2A formed on the remaining side. The heat-sensitive layer 2A is a layer coated with a coloring agent that develops color at a predetermined temperature higher than room temperature. Recording paper (plain paper) is placed on the ink layer 1B side of this thermal recording medium 2, and a thermal pulse is applied to it by a thermal head. After that, the recording paper is separated from the thermal recording medium 2.
As a result, a recorded image using the thermal transfer ink is obtained on the recording paper side, and a recorded image using the coloring agent is obtained on the thermal recording medium 2 side.

However, with such a thermal recording medium, not only is it impossible to record only on plain paper, but also a negative image appears on the ink layer 1B side of the thermal recording medium that has already been recorded, which is not good-looking. .

The present invention was made in view of these circumstances, and is capable of printing two sheets of plain paper using one thermal head.
An object of the present invention is to provide a heat-sensitive recording device capable of color recording or two-sheet copying.

In the present invention, the thermal recording device has the following configuration.

(i) Between the thermal head 4 and the back roller 5, there is a first
An ink donor sheet having ink layers 3A, 12A on the back roller 5 side of the base paper, and second ink layers 3B, 12B on the thermal head 4 side of the base paper, which can be transferred by the output of the thermal head 4. 3 and 12, and the first ink layer 3 is applied to the sheets 11 and 13 supplied between the ink donor sheets 3 and 12 and the back roller 5.
A first recording in which the inks of A and 12A are transferred and the inks of second ink layers 3B and 12B are transferred to the ink image carrier 9 supplied between the ink donor sheets 3 and 12 and the thermal head 4. Part A.

(ii) Sheet 1 supplied to the ink image side of the ink image carrier 9 on the downstream side of the first recording section A
1 and 14 and the ink image on the ink image carrier 9, the second recording unit B brings the ink images onto the ink image carrier 9 into thermal contact with each other and transfers the images.

This enables two-color recording on plain paper or two-sheet copying.

The present invention will be explained in detail with reference to Examples below.

FIG. 3 shows the cross-sectional structure of an ink donor sheet for two-color recording. The ink donor sheet 3 has a first ink layer 3 for performing black recording.
A and a second ink layer 3B for red recording are combined with capacitor paper (base paper) 3C with a thickness of 8 to 10 μm.
It is formed on each side of the. Each ink layer has black or red pigment dispersed in thermally transferable wax, and the coating amount thereof is adjusted to 3.5 to 4.0 g/m ² . 1st
The melting point of the second ink layer 3A is set to 60°C, and the melting point of the second ink layer 3B is set to 60°C or slightly higher.

FIG. 4 shows the main parts of a thermal recording apparatus in a first embodiment using this ink donor sheet 3. The thermal recording device includes a first recording section A consisting of a thermal head 4 and a back roller 5.
A second recording section B including a pressure roller 6 and a heat roller 7 is provided. The ink donor sheet 3 is fed out from a supply roll (not shown), passes through the first recording section A with the first ink layer 3A facing the back roller 5, and is taken up by the take-up roll 8. ing. 1st
A set of closed-loop capacitor paper 9 is circulated between the recording section A and the second recording section B while maintaining contact with the thermal head 4 or the heat roller 7.

When a recording operation is started with this thermal recording device,
Recording paper (plain paper) 11 is supplied to the first recording section A from a supply tray (not shown). The recording paper 11 is
The thermal head 4 and the back roller 5 are in contact with the first ink layer 3A of the ink donor sheet.
pass between. At this time, the back roller 5 presses the ink donor sheet 3, the capacitor paper 9 and the recording paper 11 stacked on both sides thereof against the thermal head 4, and integrally moves them in the sub-scanning direction (direction of the second recording section B). be transported to
The thermal head 4 is driven in this conveyance state.

The thermal head 4 generates heat at a relatively low temperature at a portion where red is recorded, and at a relatively high temperature at a portion where black is recorded. These amounts of heat generation are switched by changing the voltage applied to the thermal head 4 or by changing the width of the drive pulse. When relatively low-temperature heat generation occurs,
Only the second ink layer 3B becomes fluidized or sublimated, and the ink in that area is transferred to the capacitor paper 9. Furthermore, when heat is generated at a relatively high temperature, the first ink layer 3A also becomes fluidized or sublimated at the same time. At this time, the ink at that part of the first ink layer 3A is transferred to the recording paper 11, and the ink at the same part of the second ink layer 3B is transferred to the capacitor paper 9. Note that the ink of the second ink layer 3B is made of capacitor paper 3C made of the same material,
It is transferred between 9 and 9. Such transfer can be performed with extremely high reliability by appropriately adjusting the contact pressure and peeling angle of both capacitor papers 3C and 9.

The capacitor paper 9 and the recording paper 11 that have passed through the first recording section A reach the second recording section B after the same transport time has elapsed. In the second recording section B, the pressure roller 6 presses the condenser paper 9 and the recording paper 11 in a stacked state against the heat roller 7, and uniformly heats the ink transferred to the condenser paper 9.
The image is retransferred onto the recording paper 11. As a result, black and red inks are superimposed on the recording paper 11 in the area where black recording is performed, and visually black recording is performed. Further, in the area where red recording is performed, only red ink is transferred onto the recording paper 11, and red recording is performed. The recording paper on which two-color recording has been performed in this manner is discharged to a paper discharge tray (not shown).

FIG. 5 shows the cross-sectional structure of an ink donor sheet for simultaneous recording. The ink donor sheet 12 includes a first and a second ink donor sheet, both of which record in black.
Ink layers 12A and 12B are formed on each surface of capacitor paper (base paper) 12C. The melting point of the ink of the first ink layer 12A is 55~
60°C, and that of the second ink layer 12B is 60~
The temperature is set at 70℃. The thickness of the capacitor paper 12C and the amount of ink applied to each ink layer 12A, 12B are the same as in the case of the ink donor sheet described above.

FIG. 6 shows the main parts of a heat-sensitive recording apparatus in a second embodiment using this ink donor sheet 12. The thermal recording device is provided with a first recording section A and a second recording section B, which have the same configuration as the thermal recording device in the first embodiment. A loop-shaped capacitor paper 9 is similarly circulated in the first recording section A and the second recording section B.

When a recording operation is started with this thermal recording device,
From the first supply tray (not shown) to the first recording section A
Recording paper 13 is supplied. The recording paper 13 is
It passes between the thermal head 4 and the back roller 5 in contact with the first ink layer 12A of the ink donor sheet. At this time, the cross crawler 5 is
The ink donor sheet 12, the capacitor paper 9 and the recording paper 13 superimposed on both sides thereof are pressed against the thermal head 4, and are conveyed integrally in the sub-scanning direction (toward the second recording section B). The thermal head 4 is driven in this conveyance state.

When the heating element of the thermal head 4 selectively generates heat, the ink in the first and second ink layers at that location becomes fluidized or sublimated, and is transferred to the recording paper 13 and the capacitor paper 9. The melting point of the second ink layer 12B near the thermal head 4 is higher than that of the first ink layer 12A because the ink bleeds or collapses when heated to a higher temperature than the first ink layer 12A. This is to prevent this from occurring.

After recording is started in the first recording section A, the recording paper 14 is supplied from a second supply tray (not shown) to the second recording section B after a predetermined delay time has elapsed. This delay time is set equal to the transport time of the capacitor paper 9 from the first recording section A to the second recording section B. In the second recording section B, the pressure roller 6 presses the overlapping condenser paper 9 and recording paper 14 against the heat roller 7, uniformly heats the ink transferred to the condenser paper 9, and transfers the ink onto the recording paper 14. Retransfer. As a result, the first
An ink image identical to the ink image transferred to the recording paper 13 in the recording section A is also created on the recording paper 14. After the transfer recording is completed, the two recording papers 13 and 14 are
The paper is discharged to the same paper discharge tray (not shown).

This thermal recording device can do two things at the same time, such as creating a slip.
Although it is mainly used when creating one recording image, it is also possible to record only one recording image. In this case, there are two methods: reducing the amount of heat generated by the thermal head 4 and transferring ink only to the capacitor paper 9; and
Alternatively, there is a method of transferring unnecessary ink to the pressure roller 7. In the latter method, ink adheres to the back roller 5 or the pressure roller 7. However, since these inks are not heated to a temperature at which they can be transferred again, there is no possibility that they will be transferred to the recording paper 13 or 14 again.

The ink donor sheet used in each of the examples described above has solid ink that fluidizes or sublimates when heated, coated on both sides of the base paper, so it can be used for long periods of time in high temperature and humid environments. The base paper will not absorb moisture even if left alone. Therefore, wrinkles in the ink donor sheet due to moisture absorption can be completely prevented.

In the second embodiment described above, image information is recorded in the same color on two sheets or only on one sheet, but both ink layers are recorded in different colors, and the image information is recorded in different colors. Of course, it is also possible to do so.

In this way, according to the present invention, one thermal head is used to selectively transfer the ink layers arranged on both sides of the base paper, so the apparatus is more efficient than an apparatus using two thermal heads. This has the advantage that it can be manufactured in a small size and at low cost.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of a thermal recording medium used in a conventional thermal recording device, FIG. 3 is a cross-sectional view of an ink donor sheet used in the first embodiment of the present invention, and FIG. 4 is a cross-sectional view of a thermal recording medium used in a conventional thermal recording device. FIG. 5 is a cross-sectional view of an ink donor sheet used in a second embodiment of the present invention, and FIG. It is a block diagram which shows the principal part of the heat-sensitive recording device in 2nd Example. 3, 12... Ink donor sheet, 3A, 12
A: first ink layer, 3B, 12B: second ink layer, 4: thermal head, 5: back roller, 9: capacitor paper (ink image carrier),
A...first recording section, B...second recording section.

Claims (1)

[Scope of Claims] 1. A first ink layer 3A, 12A that can be transferred by the output of the thermal head 4 is provided between the thermal head 4 and the back roller 5 on the side of the back roller 5 of the base paper, and A second ink layer 3B, 12 that can be transferred by the output of the thermal head 4
The ink donor sheets 3 and 12 having B on the side of the thermal head 4 of the base paper are arranged, and the first Transferring the ink of the ink layers 3A, 12A, and transferring the ink of the second ink layer 3B, 12B to the ink image carrier 9 supplied between the ink donor sheets 3, 12 and the thermal head 4. a first recording section A, which is located downstream of the first recording section A and is supplied to the ink image side of the ink image carrier 9, and sheets 11 and 14 on the ink image carrier 9; A thermal recording device comprising a second recording section B that transfers an ink image by bringing it into thermal contact with the ink image.