JPS6249194B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a double-sided recording device that is capable of simultaneously recording on both sides of a recording medium in a thermal transfer recording device using an ink donor sheet.

A conventional double-sided recording device is shown in FIG. Figure 1 shows a double-sided recording device using thermal transfer recording technology.
a, 1b are ink donor sheet supply rolls, 2
a, 2b are thermal recording heads, 3a, 3b are ink donor sheets, 4a, 4b are winding rolls, 5a,
5b is an electric (video) signal, 6a and 6b are opposing rolls, 7 is a recording paper supply tray, 8 is a recording paper transport path, and 9 is a recording paper storage tray.

As is clear from the above-mentioned apparatus, in the conventional double-sided recording apparatus, thermal recording heads 2a and 2b are provided on both sides of the recording paper conveyance path 8. This has resulted in disadvantages in that the size of the device increases and the price of the device increases.

The object of the present invention is to eliminate the above-mentioned drawbacks, to enable recording on both sides simultaneously with one thermal recording head, and to provide a simple, compact and inexpensive double-sided recording device.

The present invention will be explained below by way of examples. First, the schematic structure of the present invention will be explained with reference to FIG. A video signal is input to the thermal recording head 11 from a terminal 17, and the thermal recording head is heated to a predetermined temperature based on the video signal. Ink donor sheets 12 and 13 are provided on both sides of the recording paper conveyance path 16.
The recording paper 15 has a thermal recording head 11 and an opposing roll 14.
An ink donor sheet 12,
Recorded by 13.

An embodiment of the invention will be explained in more detail with reference to FIG. FIG. 3A shows a cross-sectional view of the recording paper 15 in the width direction, and the thermal recording head 11 includes an insulating substrate 19 and heating elements 11a to 11i disposed on the substrate 19.
It consists of

A first ink donor sheet 12 is installed on the thermal recording head 11 side of the recording paper 15 (hereinafter referred to as the B side), while an ink donor sheet 13 is installed on the opposite side of the recording paper 15 (hereinafter referred to as the A side). is set up. The heating elements 11a to 11i correspond to pixels recorded on the recording paper 15.

FIG. 3B shows each heating head 1 of the thermal recording head 11.
An example of energy applied to 1a to 11i is shown. The energy applied to the heat generating heads 11a to 11i is divided into four stages: P ₀ , P _B , P _A+B and P _A . Here, the applied energy P ₀ is the recording paper 15
It is an energy that does not give any record on both sides of the plane, and is preferably set to P ₀ (≈0). The applied energy P _B is the energy for recording only the B side of the recording paper 15. Also, the applied energy P _{A + B} is the energy for recording both sides of the recording paper 15, and P _A is A
This is the energy that contributes to recording only the surface. Note that the energy applied to the thermal recording head 11 can be switched between four levels by changing the applied pulse width or voltage (power).

With reference to FIGS. 4A and 4B, the reason why any surface of the recording paper can be recorded with the above-mentioned four levels of applied energy will be explained. Now, ink donor sheet 1
2 and 13 have the same recording characteristics, and the recording characteristics are as shown in A in the figure. That is,
The energy applied to the ink donor sheet is P _B ,
If P _A+B , it is assumed that the ink on the ink donor sheet is transferred to the recording paper 15. On the other hand, if the energy applied to the ink donor sheet is Pr, Ps, the ink on the ink donor sheet is transferred to the recording paper 1.
5 shall not be transferred. An ink donor, as shown in FIG. 4A, which has the characteristic of being able to record within a certain temperature range and not being able to record outside that temperature range (low temperature side and high temperature side) can be produced using the following principle. In other words, the applied energy at the start of recording is
If Pr and the applied energy at the trailing edge of recording are Ps, ink transfer starts near Pr, and above Ps, the decoloring agent of the ink starts to react with the ink, causing decolorization. Alternatively, by allowing the ink to sublimate at temperatures above Ps, it is possible to prevent ink from remaining and recording at temperatures above Ps.

As an example of such an ink, a combination of a basic colorless dye and bisphenol A can be used. A guanidine derivative can be used as a decolorizing agent. In order to make the ink disappear at energy Ps or higher, the guanidine derivative must be contained in microcapsules with a melting point of energy Ps, or
A guanidine derivative is mixed in a binder wax having a melting point of Ps, and this is provided as a layer below the ink.

FIG. 4B shows the relationship between the energy applied to the thermal recording head 11 and the recording density of the ink donor sheet, where the solid line a represents the recording density on side B of the recording paper 15, and the dotted line b represents the recording density on side A of the recording paper 15. Indicates concentration. Now, if energy P _B or P _A+B is applied to the thermal recording head, the energy P _B or P _A+B is directly applied to the first ink donor sheet 12. The ink is on recording paper 1
It is transferred to the B side of 5. However, since thermal energy is applied to the second ink donor sheet 13 via the recording paper 15, the thermal energy applied to the second ink donor sheet is less than the energy of the thermal recording head. Therefore, when the energy applied to the thermal recording head 11 is P _B , there is no thermal energy on the second ink donor sheet 13.
When the energy applied to the thermal recording head is P _{A + B} , it becomes almost P _B. Therefore, when energy P _B is applied to the thermal recording head, only side B of the recording paper 15 is recorded, and side A is not recorded. Also, when the energy applied to the thermal recording head is P _A+B , both sides are recorded.

On the other hand, when the energy applied to the thermal recording head 11 is P _A , the energy P _A is applied to the first ink donor sheet 12, so that the ink on the first ink donor sheet 12 is decolored and transferred to the recording paper. 15
The B side of is not recorded. However, since thermal energy is applied to the second ink donor sheet 13 via the recording paper 15, energy P _A+B is applied, and side A of the recording paper 15 is recorded.

Returning again to FIG. 3, this embodiment will be explained.
Now, as shown in Figure B, the thermal recording head 1
Energy P _A+B is applied to the heating elements 11a, 11b, and 11g, energy P _B is applied to the heating element 11c, energy P _A is applied to the heating elements 11e, 11f, and 11h, and energy P ₀ is applied to the heating elements 11d and 11i. Suppose that it is applied. Then,
On the recording paper 15, as shown in A of the same figure,
Heating elements 11a, 11b, and 11g perform double-sided recording, heating element 11c records only the B side, and heating elements 11e, 11f, and 11
Only side A is recorded by h. Heat generating element 11
d, 11i, no recording is made on the recording paper 15. Note that 18 in FIG. A indicates ink recorded on the recording paper 15.

By controlling the energy applied to the thermal recording head in accordance with the image information recorded on sides A and B of the recording paper 15 in this way, it is possible to simultaneously record different images on both sides of the recording paper. can.

In the above embodiments, the first and second ink donor sheets have the same recording characteristics, but it is not necessarily necessary that the two have the same recording characteristics, and as shown in FIG. It is sufficient if the recording characteristics of the two partially overlap, as shown in FIG.

In FIG. 5, if the recording characteristic of the ink donor sheet 12 on the thermal recording head 11 side is A, and the recording characteristic of the ink donor sheet 13 on the back side is B, then the recording characteristic B disappears at a certain temperature, for example, T _{A + B} or higher. On the other hand, the recording characteristic B has the characteristic that recording can be obtained at T _A+B or more.

When performing double-sided recording using an ink donor sheet having such recording characteristics, for example, when energy is applied to the thermal recording head 11 to give a temperature of T _B to the ink donor sheet 13, the recording paper 15
The ink of the ink donor sheet 13 is transferred to. At this time, since the temperature applied to the ink donor sheet 12 is below T _{A +B} , the ink on the ink donor sheet 12 is not transferred to the recording paper 15 .

On the other hand, if the energy applied to the thermal recording head 11 is controlled so that the temperature applied to the ink donor sheet becomes T _A , the ink donor sheet 1
Only ink No. 2 is transferred onto the recording paper 15. Furthermore, the temperature applied to the ink donor sheet is T _A+
When set to _B , the inks on the ink donor sheets 12 and 13 are simultaneously transferred to the recording paper 15.

Therefore, by adjusting the energy or temperature applied to the thermal recording head 11 depending on the images to be recorded on both sides of the recording paper 15, different images can be recorded on both sides of the recording paper.

In the above embodiment, the energy applied to the thermal recording head was set in four stages, but it may be set in five stages. In this case, the recording characteristics of the first and second ink donor sheets would not overlap at all. good.

Furthermore, by changing the color of ink on the ink donor sheets disposed on both sides of the recording paper 15, images of different colors can be recorded on the front and back sides of the recording paper.

As described above, according to the present invention, ink donor sheets are provided on both sides of the recording paper, and the energy applied to the thermal recording head is controlled according to the image information recorded on the front and back sides of the recording paper. Different images can be recorded on the front and back sides of recording paper at the same time. Therefore, since it is possible to simultaneously record on both sides of the recording paper with one thermal recording head, the apparatus is simple, compact and inexpensive, and has the advantage of high recording speed.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional double-sided recording device using an ink donor sheet, FIG. 2 is a schematic diagram of an embodiment of the present invention, and FIG. 3 is a diagram of a conventional double-sided recording device using an ink donor sheet. An explanatory diagram showing how double-sided recording is performed, FIG. 4 is a recording characteristic diagram of the ink donor sheet used in one embodiment of the present invention, and FIG. 5 is a diagram showing the recording characteristics of the two ink donor sheets used in the above embodiment. FIG. 7 is another recording characteristic diagram. 11... Thermal recording head, 12, 13... Ink donor sheet, 14... Opposing roll, 15... Recording paper, 17... Terminal.

Claims (1)

[Scope of Claims] 1. A recording paper conveyance path, first and second ink donor sheets provided on both sides of the recording paper conveyance path, and the first ink donor sheet.
A thermal recording head is provided on the side of the ink donor sheet, and the amount of energy required to transfer the ink from the first and second ink donor sheets onto the recording paper is determined as P _A and P _B , respectively. A double-sided recording device characterized in that, when P _A and P _B satisfy the following relationship. P ₁ ≦P _A ≦P ₂ , P ₃ ≦P _B ≦P ₄ However, P ₁ , P ₂ , P ₃ , P ₄ are the magnitudes of energy that satisfy the relationship of P ₁ <P ₃ ≦P ₂ <P ₄ .