JP3029631B2 - Transfer paper - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper to be used for repeated thermal transfer printing.

2. Description of the Related Art Conventionally, recording devices such as printers and facsimile machines that use thermal transfer have been widely used as devices capable of reducing the size, cost, and maintenance of the device.
A thermal transfer recording medium used in a thermal transfer recording apparatus is a medium in which a thermal transferable ink layer is simply provided on a base material.
Since the heated portion of the ink layer is transferred every time and cannot be used repeatedly, there is a problem in running cost. Therefore, a thermal transfer recording medium that can be used repeatedly is required, and various methods have been proposed until now.

Conventionally known examples include JP-A-54-68253 and JP-A-55-1.
What provided the microporous ink layer on the base material disclosed in 05579 publication so that the heat-fusible ink oozed out little by little, the base material disclosed in JP-A-58-212993 A method in which a porous film is provided on the upper ink layer to control the amount of ink flowing out.
Japanese Patent Application Laid-Open No. 127192 proposes a method in which an ink layer is provided via an adhesive layer and the ink is peeled off little by little and transferred.

However, when thermal transfer printing is repeatedly performed on these thermal transfer recording media using a general-purpose transfer receiving paper, there is a disadvantage that the image density decreases and the image density change of the print is large.

For the receiving paper, JP-A-57-182487, JP-A-61-61487
JP-217289, JP-A-61-248791, JP-A-61-2662
96 publication, JP-A-61-284486, JP-A-62-162590, JP-A-62-202788, JP-A-62-160287, JP-A-62-257888, JP-A-62-278808 , JP 63
-19289 gazette, JP-A-63-69685, JP-A-63-17808
2. As disclosed in JP-A-1-188392, a support having a highly oil-absorbing coating layer on a support has been proposed.

However, even when a highly oil-absorbing transfer receiving paper is used in repeated thermal transfer printing, high-resolution thermal transfer recording with a high print density and little decrease in density cannot be obtained.

Also, when the roughness index (Vr) of the Bristow method (J. TAPPI, paper pulp test method No. 51-87) described in JP-A-2-9688 is 5 ml or more,
It is disclosed that satisfactory recording is obtained, but in repetitive printing, high-density thermal transfer recording with low density reduction was not obtained even with such a transfer-receiving paper while maintaining high printing density. .

[Problems to be Solved by the Invention] In view of such circumstances, the present invention provides a transfer paper that maintains a high print density even after repeated thermal transfer printing, forms a low-density drop, and forms a high-resolution thermal transfer record. Is what you do.

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, the absorption characteristics of the first-class liquid paraffin, which is close to the physical properties of the ink on the thermal transfer recording medium when melted, are specified. Have been found to be effective as paper to be transferred, and have led to the present invention.

That is, the present invention relates to a transfer paper for thermal transfer recording for a large number of times, wherein the absorption coefficient measured under a pressure of 0.1 MPa by the Bristow method (J. TAPPI No. 51-87) using reagent grade liquid paraffin. The paper to be transferred having a (Ka) of 0.05 to 0.75.

As described above, the transfer paper of the present invention has an absorption coefficient (Ka) of reagent first-grade liquid paraffin of 0.05 to 0.1 under a pressure of 0.1 MPa.
75, preferably 0.10 to 0.50.

When Ka is less than 0.05, the ink receptivity is inferior, and the amount of transfer of the ink to the receiving paper in one printing operation is small, so that the density is small but the high printing density cannot be obtained. Ka is 0.75
If it is larger, the amount of ink transferred to the transfer receiving paper in one printing operation is large, and the ink held by the thermal transfer recording medium is squeezed out. The density is remarkably low, which is not suitable for repeated printing.

When the Ka is 0.05 to 0.75, the Beck smoothness is 200 to 2
If it is 000 sec, a higher resolution image can be obtained.

If it is shorter than 200 seconds, image blur occurs. Also, 2
If it is over 000 seconds, a high-resolution image will be obtained,
Sufficient image density cannot be obtained.

Ka is controlled by the density, coating amount, coating physical properties, etc., and any processing may be performed on the receiving paper as long as it has a Ka in this range.

EXAMPLES Next, the present invention will be described in more detail with reference to examples. The amounts (parts) of the components described in the examples are parts by weight.

Example 1 Coating liquid Calcined clay 100 Styrene butadiene polymer 20 Sodium polyacrylate 20 Coated to a high quality paper with a wire bar at a coating amount of 30 g / m ² , calendered, and Beck smoothness 165se
c, transfer paper of ka 0.51 was obtained.

Example 2 Coating liquid Silica 100 Water-soluble polyester resin 40 Casein 10% aqueous solution 100 Calcium stearate 2 Water 63 Coated on a high quality paper with a wire bar at a coating amount of 10 g / m ² , calendered and Beck smoothed Degree 530sec,
A transfer paper of Ka0.15 was obtained.

Example 3 LBKP 80 with 350 ml of C.S.F. freeness NBKP 20 with 350 ml of freeness CCA 3 water 7 cationized starch 0.02

5% aqueous solution of Kuraray PVA217 Waterproofing agent Polyfix 203 Keep the hand-made sheet at 70 ° C, immerse the hand-made sheet for 5 minutes, put it on a press after standing, dry at 60 ° C, and perform Beck smoothness 36
Transfer paper having 0 sec and Ka of 0.26 was obtained.

Comparative Example 1 TRW-1 of Jujo Paper, which is currently commercially available, was used as a transfer paper. Ka = 1.01, Beck smoothness = 205 sec.

Comparative Example 2 A commercially available art paper was used as a transfer target. Ka = 0.03, Beck smoothness 2050 sec, and evaluation was performed by the following method.

<Thermal transfer recording medium> Carbon black 15 parts Candelilla wax 60 parts Oxidized polyethylene wax 23 parts Terpene resin (dispersant) 2 parts After the above components were charged into a sand mill vessel, they were dispersed at 110 ° C to obtain a uniform ink. Then set the system to 65 ° C,
10 parts of a low melting point oil-soluble dye benzol black and 675 parts of methyl ethyl ketone / toluene (2/1 ratio) were added, and redispersion was performed at 32 ° C. The dispersion was allowed to cool at room temperature to obtain a hot-melt gelled ink. Using this ink, the following ink layer coating solutions were prepared, and each ink layer was prepared.

<Preparation of first ink layer> Heat-meltable gelled ink 10 parts 20% solution of vinyl chloride-vinyl acetate copolymer in methyl ethyl ketone / toluene (2/1 ratio) 3 parts Azobisisobutyronitrile 0.1 part The above components After mixing, a 4.5 μm-thick PET film was coated on one side of a heat-treated base material to a thickness of 8 μm and dried at 75 ° C. to form a first ink layer.

<Preparation of Second Ink Layer> Hot-melt gelled ink 10 parts 20% solution of vinyl chloride-vinyl acetate copolymer in methyl ethyl ketone / toluene (2/1 ratio) 3 parts After mixing the above components, the first ink layer The film was applied thereon to a thickness of 2 μm and dried and foamed at 110 ° C. to form a second ink layer to obtain a thermal transfer recording medium.

<Printing test> The thermal transfer recording medium obtained as described above was mounted on a line printer, and the same position of the thermal transfer recording medium was repeatedly printed four times, and the image density of each time was measured with a reflection densitometer (RD Macbeth RD). -914). Table 1 shows the results.

Printing conditions: Thermal head: Line thin film head type Platen pressure: 230 gf / cm Peeling angle of transfer recording medium: 45 ゜ (relative to specific transfer paper) Applied energy: 23 mJ / mm ² Printing speed: 2 inches / sec [ Effect] As described above, the transfer paper of the present invention has a Ka of 0.05 to 0.1.
By maintaining a high print density in repeated thermal transfer printing by setting it to 75, an image with a small decrease in density is formed, and further, Ka is set to 0.05.
With a Beck smoothness of 200 to 2000 sec, a high-resolution image can be formed, and an optimum transfer paper for repeated thermal transfer printing can be obtained.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-9688 (JP, A) JP-A-2-3394 (JP, A) JP-A-61-284486 (JP, A) JP-A-62-1986 282982 (JP, A) JP-A-60-110488 (JP, A) JP-A-62-66988 (JP, A) JP-A-61-89888 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) B41M 5/38-5/40

Claims (2)

(57) [Claims] 1. A Bristow method (J. TAPPI) using a first-grade liquid paraffin as a transfer paper for thermal transfer recording a number of times.
No. 51-87), a transfer paper characterized in that the absorption coefficient (Ka) measured under a pressure of 0.1 MPa is 0.05 to 0.75. 2. An absorption coefficient (Ka) measured under a pressure of 0.1 MPa by a Bristow method (J. TAPPI No. 51-87) using primary liquid paraffin reagent is 0.05 to 0.75, and 2. The receiving paper according to claim 1, wherein the smoothness is 200 to 2000 sec.