JP2002234265A - Thermal transfer recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer recording sheet capable of appropriately recording a printed image. SOLUTION: This thermal transfer recording sheet 16 comprises a base material 16a, a dye layer 16b formed on one of he sides of the base material 16a and a back layer 16c formed on the other side of the base metier 16a. In addition, a thermal head 11 is arranged on the back layer 16 side. The coefficient of friction between the back layer 16 are the thermal head 11 is A<0.13 when the maximum value-the minimum value in a single line period is given as A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording sheet, and more particularly to a thermal transfer recording sheet excellent in printing.

[0002]

2. Description of the Related Art A thermal transfer recording sheet having a substrate, a dye layer provided on one surface of the substrate, and a back layer provided on the other surface of the substrate has been known. In such a thermal transfer recording sheet, the back layer side is heated by the thermal head, and the heated dye layer is transferred to the photographic paper side.

In the printing operation using such a thermal transfer recording sheet, thermal transfer is performed while the thermal transfer recording sheet moves relatively to a thermal head. Therefore, inexpensive substrates such as polyethylene terephthalate and polyethylene naphthalate are used. Only with insufficient heat resistance and lubricity,
Good recording cannot be performed. Therefore, the heat transfer recording sheet is provided with a heat-resistant back layer on the other surface of the substrate as described above.

[0004] Such a back layer is generally formed using a polymer resin as a main binder. When heated by a thermal head, the back layer is heated to a temperature exceeding the melting or softening point, and its physical properties are deteriorated. Will change. Along with this, the back friction fluctuates, and this fluctuation causes print wrinkles and print unevenness. In order to solve such a problem, it has been proposed to eliminate the difference between the friction value during printing and the friction value during non-printing, and various devices have been devised.

[0005]

However, there are many cases where the above problems cannot be solved even with a thermal transfer recording sheet having a back layer produced as described above.

For example, a method for accurately measuring the coefficient of friction between the back layer and the thermal head has not been realized. Conventionally, a friction coefficient is obtained by applying a measured value to a low-pass filter, or a friction coefficient is obtained from an average value of measured values in 0.1 second to 1 second.

However, in actual thermal transfer, the amount of heat printed by the thermal head is controlled by adjusting the ON / OFF time ratio of the intermittent pulse in units of the line cycle. Therefore, the friction coefficient between the back layer and the thermal head appears as a vibration fluctuation having a constant amplitude in synchronization with the line cycle. However, in general, the line cycle differs depending on the printer, but it is approximately 50 msec.
Since it is as short as about 0.5 msec, it is not possible to accurately determine the vibration fluctuation. For this reason, even in the development of the backing material, the fact is that even the vibration fluctuation accompanying the line cycle of the friction between the backing layer and the thermal head is not considered.

The present invention has been made in view of the above points, and provides a thermal transfer recording sheet capable of accurately determining a coefficient of friction between a back layer and a thermal head so as to enhance printability. With the goal.

[0009]

The present invention comprises a substrate, a dye layer provided on one surface of the substrate, and a back layer provided on the other surface of the substrate. In a thermal transfer recording sheet that is heated to thermally transfer a dye layer to photographic paper, A = the maximum value of the coefficient of friction between the back layer and the thermal head during one line cycle of the thermal head−the back surface of the thermal head during one line cycle A thermal transfer recording sheet characterized in that, when the coefficient of friction between the layer and the thermal head is a minimum value, A <0.13 in the entire density region of the print.

According to the present invention, the fluctuation of friction during one line period can be eliminated, and by suppressing the amplitude of the fluctuation of friction in this way, a thermal transfer recording sheet excellent in printing can be obtained.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 11 are diagrams showing an embodiment of the present invention. First, the thermal transfer recording sheet (ink ribbon) 16 according to the present invention will be described with reference to FIG. Thermal transfer recording sheet (ink ribbon) 16
Is a film substrate 16a of polyethylene terephthalate having one surface subjected to an easy adhesion treatment,
6a includes a dye layer 16b provided on one surface and a back layer 16c provided on the other surface of the film base 16a.

Of these, the dye layer 16b is located on the photographic paper 17 side described later, and the back layer 16c is located on the thermal head 11 side described later.

A thermal transfer recording sheet 16 shown in FIG. 11 is set together with a printing paper 17 in a thermal transfer printer 10 having a frictional force measuring function shown in FIG. The thermal transfer recording sheet 16 is the thermal head 11
, The dye layer 16b is thermally transferred to the photographic paper 17 side.

In FIG. 1, during the thermal transfer step, the thermal transfer sheet 16 moves relatively to the thermal head 11,
During this time, a frictional force is generated between the back layer 16c of the thermal transfer sheet 16 and the thermal head 11.

The frictional force between the back layer 16c of the thermal transfer sheet 16 and the thermal head 11 is represented by: A = the maximum value of the coefficient of friction of the thermal head 11 during one line cycle−the friction of the thermal head 11 during one line cycle. When the coefficient has the minimum value, A <0.13 in the entire density region of the print.

As described above, in the entire density region of the print, A
<0.13, the thermal transfer recording sheet 16
The variation in the coefficient of friction between the printing of the image and the non-printing of the thermal transfer recording sheet 16 can be eliminated, and the printing aptitude for the printing paper 17 can be improved.

Incidentally, the coefficient of friction between the back layer 16c of the thermal transfer recording sheet 16 and the thermal head 11 can be measured using the thermal transfer printer 10 with a frictional force measuring function while using the thermal transfer printer 10 as an actual machine. it can.

Next, the thermal transfer printer 10 with the frictional force measuring function will be described.

As shown in FIG. 1, a thermal transfer printer 10 having a frictional force measuring function includes a printer main body 10a slidably supported by a support shaft 12, a thermal head 11 attached to the printer main body 10a, and a thermal head 11 And a platen roller 14 provided so as to face the image forming apparatus.

The printer body 10a includes a support shaft 1
The thermal head 11 has a substantially triangular shape centered at 2
Is provided at the lower end A of the printer main body 10a, and near the right end C of the printer main body 10a, there is provided a detection unit 13 which comes into contact with the swinging printer main body 10a and obtains the oscillating power of the printer main body 10a. Note that the support shaft 12 of the printer main body 10a is disposed at a point B.

The platen roller 14 is pressed toward the thermal head 14 by a pressing mechanism 18 provided on the base 20, and presses the thermal transfer recording sheet (ink ribbon) 16 and the printing paper 17 with the thermal head 14 at a constant pressure. It is designed to be pinched.

As described above, the thermal transfer recording sheet (ink ribbon) 16 comprises a substrate 16a, a dye layer 16b provided on one surface of the substrate 16a, and a back layer provided on the other surface of the substrate 16a. 16c, the dye layer 16b is heated by the thermal head 11 from the back layer 16c side.
Can be transferred to the photographic paper 17 side.

Further, the ink ribbon 16 and the printing paper 17 are shown in FIG.
Of when conveyed in the arrow _{L 1} direction, the printer main body 10a
Abuts the detecting unit 13 swings in the arrow L ₂ direction about the support shaft 12. At this time, the oscillating power of the printer body 10a is obtained by the detection unit 13, and a signal from the detection unit 13 is transmitted to the conditioner 13a, and the conditioner 13a reduces the frictional force between the thermal head 11 and the ink ribbon 16. You can ask.

As such a detecting section 13, a piezo element type load cell or a strain gauge type load cell can be used.

In the vicinity of the lower end of the printer body 10a,
Release plate 15 for separating ink ribbon 16 discharged from thermal head 11 of printer body 10a from photographic paper 17
Is provided. Further, the thermal transfer printer has an ink ribbon winding / unwinding mechanism (not shown) and an image receiving paper transport mechanism (not shown). Each mechanism other than the printer main body 10a shown in FIG. 1 is independently fixed so as not to interfere with the swing of the printer main body 10a, and does not affect the measurement.

Next, the operation of the present embodiment having the above configuration will be described.

First, the printing paper 17 and the ink ribbon 16 are
While being nipped by the thermal head 11 and the platen roller 14, it is conveyed in the arrow L ₁ direction in FIG.

At this time, a drive control circuit (not shown)
The energization of the thermal head 11 is performed, and the dye layer 16b of the ink ribbon 16 is transferred to the printing paper 17 to perform printing.

The printing paper 17 and the ink ribbon 16 are separated from each other by the release plate 15 after leaving the thermal head 11.

During this time, as shown in FIGS. 2 (a), 2 (b) and 2 (c), the power supply time to the thermal head 11 is controlled by the drive control circuit in units of one line cycle. Is adjusted. The thermal head 11 moves relative to the printing paper 17 and the ink ribbon 16 by the size of one dot (thickness of one line) during one line cycle.

Here, as shown in FIG. 2 (a), if no current is supplied to the thermal head 11, the printing result becomes white. As shown in FIGS. 2B and 2C, the print density increases as the energizing time increases.

In practice, the drive control circuit often performs more detailed energization control for the sake of the drive control circuit or for efficient heat control. In any case, one line cycle is taken as the control repetition unit, and the print density of the dot (line) is determined by the ratio of the heating time of the thermal head 11 (pulse duty) within the line cycle. Further, even in the printing of the high density portion, the ON / OFF control of the heating is performed by providing the non-energization time at a fixed rate from the viewpoint of protection of the thermal head 11.

The one-line cycle varies depending on the printer, but is about 50 msec to 0.5 msec, and the size of one dot (thickness of one line) is about 10 μm.
m to 200 μm.

While the thermal head 11 repeats the heating ON / OFF as described above, a frictional force is generated between the thermal head 11 and the back layer 16c of the ink ribbon 16.

[0035] When the frictional force between the back surface layer 16c of this thermal head 11 and the ink ribbon 16 occurs, the printer main body 10a is swung in the arrow L ₂ in Fig. 1 about the support shaft 12, the printer The main body 10a contacts the detection unit 13. At this time, the detecting unit 13 detects the swinging power of the printer main body 10a.

As shown in FIG. 1, the distance between the thermal head 11 provided at the lower end (one end) A of the printer main body 10a and the support shaft 12 located at the point B is represented by AB, Assuming that the distance between the right end (the other end) C and the support shaft 12 is BC, the thermal head 11 and the back layer 16 c of the ink ribbon 16 are controlled by the conditioner 13 a based on the swinging power obtained by the detection unit 13. The frictional force between

(Equation 1) Is required.

Next, based on the frictional force between the thermal head 11 and the back layer 16c, the coefficient of friction between the thermal head 11 and the back layer 16c can be obtained.

In this apparatus, since the thermal head 11 itself swings, there is a concern that the swing may affect printing. In this case, the distance B between the support shaft 12 and the right end C
If C is made larger than the distance AB between the support shaft 12 and the lower end A, the swing distance of the thermal head 11 can also be suppressed by the leverage principle.

This time, it was confirmed by a preliminary experiment conducted in advance that no difference was observed between the printing result of this apparatus and the printing result of each commercially available printer.

As described above, using the thermal transfer printer 10 as an actual machine, the ink ribbon 16 is heated by the thermal head 11 and printed while the ink ribbon 16 and the printing paper 17 are held between the thermal head 11 and the platen roller 17. Necessary printing can be performed on the paper 17. At this time, the frictional force and the friction coefficient between the back layer 16c of the ink ribbon 16 and the thermal head 11 can be measured with high accuracy. Therefore, the frictional force between the back layer 16c of the ink ribbon 16 and the thermal head 11 is reliably measured according to the actual situation, and an appropriate material for the ink ribbon 16 can be selected based on the frictional force. .

(Examples) Hereinafter, specific examples of the present invention will be described. First, the following was produced as the ink ribbon 16.

That is, a polyethylene terephthalate base film 16a (5.2 μm in thickness / manufactured by Toray Co., Ltd.) having one surface subjected to an easy adhesion treatment was prepared. Next, a coating solution having the following composition was applied to the other surface of the base film 16a.

In the coating solution, the weight ratio represents the solid content ratio. The coating solution is appropriately diluted with methyl ethyl ketone / toluene, applied to the base film 16a with a bar coder so that the coating amount becomes 1.0 g / m ^2, and thus applied to the other surface of the base film 16a. The back layer 16c was formed.

In the following composition, (* 1)
Aging was performed at 60 ° C. for 3 days to cure the composition.

<Example 1> Polyamideimide resin 50 parts by weight (HR-15ET / Toyobo Co., Ltd.) Polyamideimide silicone resin 50 parts by weight (HR-14ET / Toyobo Co., Ltd.) Zinc stearyl phosphate 10 parts by weight Part (LBT1830 / manufactured by Sakai Chemical Co., Ltd.) Talc (microace P-3 / manufactured by Nippon Talc Co., Ltd.) 10 parts by weight Polyester resin (Byron 220 / manufactured by Toyobo Co., Ltd.) 2 parts by weight <Example 2> Polyamideimide resin 50 parts by weight (HR-15ET / Toyobo Co., Ltd.) Polyamideimide silicone resin 50 parts by weight (HR-14ET / Toyobo Co., Ltd.) Zinc stearyl phosphate 20 parts by weight (LBT1830 / Sakai Chemical Co., Ltd.) )) Talc (Micro Ace P-3 / Nippon Talc Co., Ltd.) 10 parts by weight POLYS Resin (Byron 220 / Toyobo Co., Ltd.) 2 parts by weight <Comparative Example 1> Polyvinyl butyral resin 30 parts by weight (S-REC BX-1 / Sekisui Chemical) Zinc stearyl phosphate 30 parts by weight (LBT1830 / Sakai Chemical) Crosslinked powder of urea resin 4 parts by weight (organic filler (particle size 0.14 μm) / Nippon Chemical) Melamine resin crosslinked powder 5 parts by weight (Eposter S (particle size 0.3 μm) manufactured by Nippon Shokubai Chemical) Comparative Example 2 Acrylic Resin 80 parts by weight (Dianal BR-108 / Mitsubishi Rayon) Amino-modified silicone (KF-857 / Shin-Etsu Chemical) 6 parts by weight Carboxy-modified silicone 6 parts by weight (X-22-102C / Shin-Etsu Chemical) Aerosil Silica (R812 / Nippon Aerosil) 20 parts by weight Silicone resin particles 3 parts by weight (Trefin B7 (30S / Toray Silicone) <Comparative Example 3> (* 1) Polyester polyol 20 parts by weight (Sumitomo Bayer / Dismophen 651) Polyfunctional isocyanate (Nippon Polyurethane / Coronate L) 20 parts by weight Alcohol-modified silicone oil 4 parts by weight Catalyst 0.2 parts by weight <Comparative Example 4> (* 1) 15 parts by weight of polyvinyl butyral (S-LEC BX-1 / manufactured by Sekisui Chemical Co., Ltd.) 35 parts by weight of polyisocyanate (Bernock D450 / manufactured by Dainippon Ink) Phosphate ester surfactant 10 Part by weight (Plysurf A208S / Daiichi Kogyo Seiyaku Co., Ltd.) 3 parts by weight of talc (Micro Ace P-3 / Nippon Talc) The surface was coated with a dye layer 16b having the following composition. Ink ribbons 16 according to 1-2 and Comparative Examples 1-4 were produced.

Dye 1 (MS Red G / Mitsui Toatsu Co., Ltd.) 30 parts by weight Dye 2 (Macrolex RVR / Bayer) 12 parts by weight Polyvinyl acetal resin (KS-5 / Sekisui Chemical) 40 parts by weight Hydrocarbon-based wax 3 parts by weight (Microfine MF-8F / Dura Co., Ltd.) The printing paper 17 is a CANON printer CD.
The printing paper HS-36IP for -300 was used.

Next, the ink ribbon 16 and the printing paper 17 in the examples and comparative examples were set on the thermal transfer printer 10.

In the printer body 10a of the thermal transfer printer 10, the distance A between the support shaft 12 and the lower end A is
The relationship between B and the distance BC between the support shaft 12 and the right end C is AB: BC = 1: 1. ∠ABC is 90 °. Further, as the detection unit 13, a strain gauge type LM-5KA-P (manufactured by Kyowa Electric Co., Ltd., capacity 50N
-The rated output was 1.005 mV / V). Detector 13
DCV-700A of DC bridge power supply system with excellent high frequency response as conditioner 13a connected to
(Manufactured by Kyowa Denki) was used.

Finally, the output from the conditioner 13a was weighted and calculated as a frictional force.

The feed speed of the printing paper 17 and the ink ribbon 16 was set to 84 μm / line, and the printing pressure was set to 40 [N]. The resistance value of the thermal head is 1586 ohm / dot, and the number of heating elements of the thermal head is 720 dots (60.
(5 mm width). The applied voltage is 12.5V
And

As shown in FIG. 3, the energization of the thermal head 11 is performed only for 768 lines, the number of gradations is controlled in 12 steps of 0 to 11 gradations, and the pulse duty is 80% at the time of 11/11 gradation. did. The actual print pattern is as shown in FIG.

Each of the ink ribbons 16 described in the above embodiment is used.
Was able to print by cutting and pasting on another ink ribbon that was previously processed into a roll shape.

Next, the line cycle is set to 4 msec, 6 msec.
4 (a) and FIG. 4 (b) are respectively displayed on the output of the detection unit 13 when it is changed. As shown in FIGS. 4A and 4B, in both cases of 4 msec and 6 msec,
When the time axes of the graphs shown in FIGS. 4A and 4B are enlarged and displayed, they become as shown in FIGS. 5A and 5B, respectively.
As shown in FIGS. 5A and 5B, it can be seen that the vibration of the frictional force coincident with the line cycle is captured.

Next, a conventional example of the present invention will be described with reference to FIGS. As shown in FIG. 6, a head mount 25 was set on a movable stage 26, and a platen roller 14 and a thermal head 11 were provided on the head mount 25 to produce a friction force measuring device as a conventional example. Next, the ink ribbon 16 and the printing paper 17 are passed between the platen roller 14 and the thermal head 11, and the ink ribbon 16 and the printing paper
And the ink ribbon 16 and the printing paper 17 were connected to the detection unit 23 via the tension jig 24. It was then measured by the detecting unit 23 a frictional force between the thermal head 11 and the ink ribbon 16 by moving the movable stage 26 in the arrow L ₃ direction in FIG.

FIG. 7 shows the measurement results at this time.

As shown in FIG. 7, for example, when the line cycle is 4
In the case of ms, a waveform like the present invention is not seen. This is because, in the device according to the conventional example, the vibration change accompanying the line cycle is attenuated in the measurement system.

Next, in the present invention, the maximum value, the minimum value, and the average value of the frictional force determined by the detection unit 13 are determined for each line cycle, and the gap between the maximum value and the minimum value is defined as the amplitude ( (FIG. 8).

It is presumed that the conventional measuring method measures the value corresponding to the average value.

Next, the maximum value, the minimum value, the average value, and the amplitude of the frictional force were plotted for the 0 to 768 lines (FIG. 9) and for the 0 to 11 gradations (FIG. 10).

Then, the above Example 1-2 and Comparative Example 1
-4, the frictional force was divided by the printing pressure to determine the coefficient of friction.

The coefficient of friction corresponding to the ink ribbon 16 according to Example 1-2 and Comparative Example 1-4 is the maximum value (Max) in one line cycle for each of the gradations 0-11.
(L)) its minimum value during one line cycle (MIN
(L)) and its average value during one line cycle (Ave
(L)).

At the same time, A = 1 the maximum value of the friction coefficient during one line cycle minus the minimum value of the friction coefficient during the one line cycle.

Tables 1 and 2 show the results. Here, Table 1 shows the results of Example 1-2, and Table 2 shows Comparative Examples 1-4.
The result is shown.

[0064]

[Table 1]

[Table 2] Next, Example 1-2 and Comparative Example 1 shown in Tables 1 and 2
With respect to -4, the result of printing on the printing paper 17, for example, a ghosting phenomenon and a banding phenomenon caused by uneven feeding were observed.

Table 3 shows the printing results. In Table 3, a
Is Av at OFF (0 gradation) and ON (255 gradation)
e indicates the difference in e (L), b indicates the maximum value of A value, and performance 1
Indicates the result of the ghosting phenomenon, and the performance 2 indicates the result of the banding phenomenon.

[0066]

[Table 3] As is clear from Table 1-3, in Example 1-2, gradation 0
At -12 (all density regions), the A value was 0.13 or less, and it can be seen that the printing results were all good in Example 1-2.

Ghosting is improved in Comparative Examples 1 and 2 in which the difference between the average values estimated to correspond to the measured values in the conventional example is eliminated. This is disclosed in
155162. However, in Comparative Examples 1 and 2, since the A value was large, banding occurred. Finally, to improve banding, A
It is necessary to measure the value and keep it to 0.13 or less.

[0068]

As described above, according to the present invention, the fluctuation of friction during one line cycle can be suppressed small, and the amplitude of friction fluctuation can be suppressed, whereby a thermal transfer recording sheet excellent in printing can be obtained. Obtainable.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a thermal transfer printer with a frictional force measuring function according to the present invention.

FIG. 2 is a diagram showing a state of energization of a thermal head and a printing result.

FIG. 3 is a diagram showing a relationship between the number of lines and the number of gradations and a printing result.

FIG. 4 is a diagram showing a measurement result from a detection unit.

FIG. 5 is an enlarged view of the measurement result shown in FIG.

FIG. 6 is a diagram showing a frictional force measuring device as a comparative example.

FIG. 7 is a diagram showing measurement results of a frictional force measuring device as a comparative example.

FIG. 8 is a diagram showing a maximum value, a minimum value, an average value, and an amplitude of a frictional force;

FIG. 9 is a diagram showing a maximum value, a minimum value, an average value, and an amplitude of frictional force for each line.

FIG. 10 is a diagram showing a maximum value, a minimum value, an average value, and an amplitude of frictional force for each gradation.

FIG. 11 shows a thermal transfer recording sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Thermal transfer printer 10a Printer main body 11 Thermal head 12 Support shaft 13 Detection part 14 Platen roller 15 Release plate 16 Ink ribbon 16a Substrate 16b Dye layer 16c Back layer 17 Printing paper 18 Pressing mechanism

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Taro Suzuki 1-1-1 Ichigaya-Kaga-cho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd. (72) Inventor Junichi Hiroi Ichigaya-Kaga, Shinjuku-ku, Tokyo 1-1-1 cho, Dai Nippon Printing Co., Ltd. F term (reference) 2H111 AA27 AA33 BA03 BA08 BA61 BA65

Claims (2)

[Claims] 1. A photographic paper comprising a substrate, a dye layer provided on one surface of the substrate, and a back layer provided on the other surface of the substrate. A = the maximum value of the coefficient of friction between the back layer and the thermal head during one line cycle of the thermal head—the distance between the back layer and the thermal head during one line cycle of the thermal head. A thermal transfer recording sheet wherein A <0.13 in the entire density region of a print when the friction coefficient is set to a minimum value. 2. The method according to claim 1, wherein the coefficient of friction between the back layer and the thermal head is measured while the thermal transfer sheet is heated by the thermal head to thermally transfer the dye layer to photographic paper. Thermal transfer recording sheet.