JPH0679877B2 - Granular polypropylene wax for dye-donor element used for thermal transfer of dye - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dye-donor element used for thermal transfer of a dye. More specifically, it relates to the use of particulate polypropylene wax in the dye layer to reduce various defects that occur in the printing operation without compromising gloss.

(Prior Art) In recent years, thermal transfer systems have been developed for the purpose of printing images produced electrically by color video cameras. According to one of the developed methods, first, the color of the electric image is divided by a color filter, and the image of each color is converted into an electric signal. Thereafter, cyan, magenta, and yellow electrical signals are generated from these electrical signals and the electrical signals are sent to the thermal transfer device. In a thermal transfer machine, cyan, magenta and yellow dye-donor elements are placed in close proximity to the dye-receiving element for printing.
These two elements are inserted between the thermal transfer head and the platen roller so that the linear thermal transfer head applies heat from the back of the dye-donor sheet. The linear thermal transfer head has many heating elements and is continuously heated in response to electric signals of cyan, magenta and yellow. In this way, a color hard copy corresponding to the image on the screen is obtained. This process and the apparatus for performing this process are described in US Pat. No. 4,62,62 entitled "Thermal Printing Device Steering Method and Device Therefor" by Brownstein.
Further details are given in No. 1,271 (November 4, 1986).

Column 6 of US Pat. No. 4,720,480, Japanese Patent No. 62/283,
176 and EP 210,838 include silicone oils,
The use of various materials such as polyalkylene glycols, paraffin waxes, fluorocarbon resins, solid particle lubricants and polyethylene waxes in the dye layer of dye-donor elements is described.

(Problems to be Solved by the Invention) When thermal dye transfer is performed, print defects are often found. For example, small non-transferred areas called "mottle" may be observed on the dye-receiving layer, or "ripple defects" resembling ripples that can be seen from a boat against the flow may be found on the dye-receiving layer. .
The "wavy defect" is due to the non-uniform speed at which the dye-donor element passes through the nip formed by the dye-receiving element and the thermal printhead. Also, the dye occasionally crystallizes on the dye-donor element, which makes it difficult to distinguish images in low-density areas, or the maximum density becomes low.

As will be apparent from the comparative tests described below, the above prior art materials are unable to eliminate or mitigate the various print defects described above, and are well-suited for reflective printing in particular. Many do not have excellent gloss.

The present invention is therefore directed to the use of particles in the dye layer of the dye-donor element so that the above-described print defects can be eliminated, mitigated, and sufficient gloss can be produced.

(Means for Solving the Problems) The above objects and other objects have been achieved by the present invention. The present invention relates to a dye-donor element used for thermal transfer of a dye, which has a dye layer containing a dye dispersed in a polymer binder other than wax, which does not transfer by heat. The dye layer has an average particle size of less than 30 μm. Yes Melting point 125
One or more types of granular polypropylene wax higher than 0 ° C.
The present invention provides a dye-donor element characterized by containing 005-0.2 g / m ² .

As used herein, "wax" refers to a plastic that is solid at ambient temperature and that melts with increasing temperature and has a viscosity in the liquid state of less than 8000 cps.

Examples of granular polypropylene waxes that can be used in the present invention include the following.

Compound 1) Micropowder polypropylene particles such as Micropro-400 ^R from Micropowder having a melting point of 140 to 143 ° C Compound 2) Ultrafine pulverization such as Micropro-600 ^{R from} Micropowder having a melting point of 146 to 149 ° C Polypropylene particles Compound 3) Ultra-finely ground polypropylene particles such as Shamrock Technology's Non-Skid 5389 ^R having a melting point of 140 to 155 ° C Compound 4) Epolene N-15 ^R of Eastman Chemical Products, which has a melting point of 163 ° C Polypropylene particles such as: The dye used in the dye-donor element of the invention is dispersed in a polymeric binder other than a wax. Examples of the polymer binder include cellulose acetate hydrogen phthalate, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose triacetate and cellulose derivatives such as the substances described in US Pat. No. 4,700,207; polycarbonate; poly (styrene). -Co-acrylonitrile), poly (sulfone) and poly (phenylene oxide) can be used.

In a preferred embodiment of the invention, cellulose acetate butyrate or cellulose acetate propionate is used as the dye binder. The amount of acetyl is 1.5 to 31
%, Propionyl is 38-48% and butyryl 15-56%.

If it is a dye that can be transferred to the dye receiving layer by the action of heat,
Any dye can be used in the dye layer of the dye-donor element of the invention. The following structural formula: Sublimable dyes such as compounds represented by and US Pat.
Particularly good results are obtained with any of the dyes disclosed in 1,830. These dyes may be used alone or in combination to form a single color image. The dye is preferably hydrophobic and the coverage is
It may be 0.05 to 1 g / m ² .

The dye layer of the dye-donor element may be coated or printed on the support by printing techniques such as gravure printing.

Any material can be used for the support for the dye-donor element of the invention provided it is dimensionally stable and can withstand the heat of the thermal printhead. As such a substance,
For example, poly (ethylene terephthalate), polyamide,
Polycarbonates, glassine paper, condenser paper, cellulose esters, fluoropolymers, polyethers, polyacetals, polyolefins and polyesters such as polyimides are mentioned. The thickness of this support is usually 2 to
The thickness may be 30 μm, and if necessary, an undercoat layer made of the substances described in US Pat. Nos. 4,695,288 and 4,737,486 may be coated.

The backside of the dye-donor element may be coated with a slipping layer to prevent the dye-donor element from sticking to the printhead. The synovial layer may contain any of the materials disclosed in U.S. Pat. Nos. 4,717,711, 4,717,712 and 4,738,950. As the polymer binder used for the sliding layer, poly (vinyl alcohol-co-butyral), poly (vinyl alcohol-co-acetal), poly (styrene), poly (vinyl acetate), cellulose acetate butyrate, cellulose acetate pro Pionate, cellulose acetate, ethyl cellulose and the like are suitable.

The amount of lubricating material used in the lubricious layer varies widely depending on the type of lubricating material, but is usually 0.001 to ² g / m ² . When using a polymeric binder, the lubricant material
0.1 to 50% by weight, preferably 0.5 to 40% by weight are used.

The dye-receiving element that is used with the dye-donor element of the invention comprises a support having a dye image-receiving layer on its surface. The support is a transparent film such as poly (ether sulfone), polyimide, cellulose ester such as cellulose acetate, poly (vinyl alcohol-co-acetal).
Alternatively, it may be poly (ethylene terephthalate). Further, the support for the dye receiving element has a reflective property such as baryta-coated paper, polyethylene-coated paper, white polyester (polyester mixed with white pigment), ivory paper, condenser paper or synthetic paper such as duPont Tyvek ^R. It may be one.

The dye image receiving layer includes, for example, polycarbonate, polyurethane, polyester, polyvinyl chloride, poly (styrene-).
Co-acrylonitrile), poly (caprolactone) or mixtures thereof. The dye image-receiving layer may be present in an amount which effectively achieves the objects of the invention. Usually, good results are obtained with a concentration of 1 to 5 g / m ² .

As mentioned above, dye-donor elements are used to form the dye transfer image. Transfer of the dye image is accomplished by heating the dye-donor element into the image as described above and transferring the dye image onto the dye-receiving element to form the dye transfer image.

The dye-donor element of the invention may be used in sheet, continuous roll or ribbon form. When using a continuous roll or ribbon, even if only one color of dye is used,
Dyes other than the above dyes such as sublimable cyan and / or magenta and / or yellow and / or black may be used alternately. For such dyes, U.S. Patent Nos. 4,541,830, 4,698,651, 4,695,287
No. 4,701,439, 4,757,046, 4,743,582,
No. 4,769,360 and 4,753,922.
Such single color, two color, three color or four color (or more) elements are included within the scope of the present invention.

In a preferred embodiment of the present invention, the dye-donor element comprises a support of poly (ethylene terephthalate) in which yellow, cyan and magenta are repeatedly coated in sequence, and the three operations described above are carried out for each of these three colors. To obtain a dye transfer image of. It goes without saying that this step may be performed with a single color to transfer a single color dye image.

The thermal dye transfer material using the present invention comprises (a) the above-mentioned dye-donor element and (b) the above-mentioned dye-receptive element, and since the dye-receptive element is superposed on the dye-donor element, the dye of the dye-donor element is The layer is in contact with the dye image receiving layer of the dye receiving element.

EXAMPLES The present invention will be described below with reference to examples.

Example 1-Print Defect Test A cyan dye-donor element was prepared by coating the following layers on a 6 [mu] m poly (ethylene terephthalate) support.

1) Titanium alkoxide (duPont Tyzor) coated from a mixed solvent of n-propyl acetate and n-butanol
TBT ^R ) (0.12 g / m ² ) undercoat layer 2) Cellulose acetate propionate (2.5% acetyl, 45% propionyl) binder (0.44 g) coated from a mixed solvent of toluene, methanol and cyclopentanone
/ m ²⁾ above cyan dye in (0.28g / m ^2), and first
A dye layer containing the granular material (0.08 g / m ² ) shown in the table.

On the back surface of this device, a titanium alkoxide (duPo) was prepared from a mixed solvent of toluene, methanol and cyclopentanone.
nt Tyzor TBT ^R ) (0.12 g / m ² ) undercoat layer, on which Henzel et al. US Application No. 062,797 (1
(September 16, 987 application) coated with a synovial layer similar to that disclosed.

The dye receiving element comprises the following layers on a support of poly (ethylene terephthalate) colored with titanium dioxide subbed with poly (acrylonitrile-co-vinylidene chloride-co-acrylic acid) (weight ratio 14: 79: 7). Produced by coating: Makrolon 5705 ^R coated from methylene chloride (Bayer AG
Polycarbonate resin (2.9 g / m ² ), 1,4-didecoxy-2,6-dimethoxyphenol (0.38 g / m ² ), FC-431
^A dye receiving layer comprising ^R surfactant (3M Company) (0.016 g / m ² ) and DC-510 ^R surfactant (0.011 g / m ² ).

A combined dye transfer was made such that the dye side of the dye-donor element strip having an area of about 10 cm x 13 cm was in contact with the dye image-receiving layer of the dye-receiving element in the same area. The dye transfer body was attached to a take-up device driven by a rubber roller having a diameter of 60 mm. TDK Thermal Head L-231 (Thermostat 26
8.0) from the dye-donor element side toward the rubber roller.
It was pressed with a force of pound (3.6 kg).

The imaging electronics were activated to draw the dye transfer between the printhead and roller at 6.9 mm / sec. At the same time, the resistive elements of the thermal print head were pulse heated 29 microseconds every 128 microseconds for a print time of 33 milliseconds per dot. Images with varying densities were drawn by increasing the number of pulses per dot from 0 to 255. The power supplied to the thermal print head is approximately 23.5V
As a result, the instantaneous peak power was 1.3 watts / dot, and the maximum total supply energy was 9.6 milligires / dot.

The dye-receiving element was separated from the dye-donor element and the unprinted area was examined. The evaluation was performed in the following four stages.

0-no unprinted area 1-slightly unprinted area 2-medium unprinted area 3-very many unprinted area The results are shown below. there were.

Control compound 1 DLX-6000 ^R polytetrafluoroethylene micropowder (duPont) with particle size <1 μm Control compound 2 Zeo 49 ^R (JM Huber) precipitated amorphous silica with average particle size 9 μm Control compound 3 Average particle size 7 μm Zeofree 153 ^R (JM Huber) precipitated amorphous silica Control compound 4 Zeosyl 200 ^R (JMHuber) precipitated amorphous silica Control compound 5 Zeothix 177 ^R (JMHuber company) Average particle size is 5 μm ) Precipitated amorphous silica Control compound 6 Microfine M8-F (Astor Wax) polyethylene wax with a melting point of 104-110 ° C This material is disclosed in Japanese patent 62 / 238,176.

Control Compound 7 MPP620XF ^R Polyethylene Wax with a melting point of 114-116 ° C. (Micro Powders) When granular polyethylene wax or polypropylene wax is added to the dye layer, there are less unprinted areas than when using conventional granular materials It is clear from the above results. However, as shown in Example 3, polyethylene wax has another problem.

Example 2-Print Defects Example 1 except that the amount of particulate matter shown in Table 2 was included.
A dye-donor element was prepared by the same method as described above. Also,
The subbing layer was coated with 0.16 g / m ^2, using the above yellow dye (0.16 g / m ²⁾ instead of cyan dyes, the amounts shown in Table 2 using the binder at 0.29 g / m ² A control yellow dye-donor element was also prepared in the same manner as in Example 1, with the presence of each of the particulate materials in Example 1.

Poly (acrylonitrile-co-vinylidene chloride-co-acrylic acid) (14: 79: 7% by weight) coated from 2-butanone (0.08 g / m ² ) layer of titanium dioxide pigmented polyethylene coated paper stock A dye receiving element was prepared by coating the following layers in the following order.

1) Makrolon 5705 ^R (Bayer coated from methylene chloride
AG) Polycarbonate resin (2.9g / m ² ), Tone PCL-3
00 ^R Polycaprolactone (Union Carbide) (0.3
8 g / m ² ) and 1,4-didecoxy-2,6-dimethoxyphenol (0.38 g / m ² ) dye receiving layer 2) Methylene chloride coated Tone PCL-300 ^R polycaprolactone (Union Carbide) (0.11 g / m ² ), FC
-431 ^R Surfactant (3M Company) (0.01 g / m ² ) and DC-510 ^R
Topcoat layer consisting of surfactant (Dow Corning) (0.01 g / m ² ) Using the produced dye-donor element and dye-acceptor element,
Printing was performed as in Example 1. It was investigated whether a low density of "wavy defects" was observed, which was caused by unevenness in the speed of passage through the thermal printhead due to the folds on the dye-donor element. The results are shown below.

Control compound 8 Castor oil Control compound 9 Polyethylene glycol having a molecular weight of 1300 to 1600 ° C. Control compound 10 Paraffin wax Compared with the conventional particulate material that causes wavy defects, when polyethylene polyethylene or polypropylene wax is used, generally wavy defects are observed. It is clear from the above results that a non-image can be formed. However, as shown in Example 4, polyethylene wax has another problem.

Example 3-Separation Impairment Testing A cyan and yellow dye-donor element was prepared according to Example 2.

Poly (acrylonitrile-co-vinylidene chloride-co-acrylic acid) (14: 79: 7% by weight) coated from 2-butanone (0.08 g / m ² ) layer of titanium dioxide pigmented polyethylene coated paper stock Dye-receiving elements were prepared by coating the following layers on top: Makrolon 5705 ^R coated from methylene chloride (Bayer AG
Company) Polycarbonate resin (2.9 g / m ² ) and 1,4-didecoxy-2,6-dimethoxyphenol (0.38 g / m ² ) dye-receiving layer Example using the dye-donor element and dye-receiving element produced A print as described in No. 1 was made. After multiple transfer from the dye-donor element to the same area of the dye-receiving element,
The ease of separation of the dye-receiving element from the dye-donor element was compared. The evaluation was performed according to the following stages.

The dye-donor element and the dye-receiving element can be separated cleanly and easily even after multiple printing of less than E-6 degrees. After printing M-2 to 3 times, a part of the area of the dye layer is a dye-receiving layer. It takes a moderate amount of effort to separate the two because they stick to each other.

Since the dye layer adheres to the dye receiving layer after only P-1 printing, great effort is required to separate the two.

The results are shown below.

It is clear from the above results that the separation can be cleaned up more clearly when granular polypropylene wax is used, as opposed to the conventional granular material which is difficult to separate the dye-donor element from the dye-receiving element. Although some of the conventional particulate materials provide good separation, they have other undesirable properties as shown in Examples 2 and 4.

Example 4-Gloss Comparative Test A dye receiving element was prepared as in Example 2.

A cyan dye-donor element was prepared in the same manner as in Example 1, except that the amount of the particulate matter shown in Table 4 was included. Printing was carried out using the dye-donor element and the dye-receiving element by the method described in Example 1 except that a uniform maximum density image was drawn with a power supply of 24.5 V and 255 pulses / dot.

The dye-receiving element was separated from the dye-donor element and the gloss (specular reflectance at a given angle of incidence) was evaluated using a Pacific Scientific (Gardner Laboratory) polygon digital gloss meter. The higher the reflectance, the better the gloss, which is desirable. The results are shown below.

It is clear from the above results that the dye-donor element of the present invention containing polypropylene wax has a higher reflectance than the conventional dye-donor element containing polyethylene wax.

(Effect of the present invention) By using particles in the dye layer of the dye-donor element according to the present invention, defects on the print can be removed and reduced, and sufficient gloss can be obtained on the surface.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor George Bonnart Bodem 55, Monroe Avenue, Pittsford, 14534, New York, United States 55 (56) References JP 62-158093 (JP, A)

Claims (1)

[Claims] 1. A dye layer containing a dye dispersed in a polymer binder other than wax, which does not transfer by heat.
In a dye-donor element used for thermal transfer of a dye; the dye layer has an average particle size of less than 30 μm and a melting point of 125
One or more types of granular polypropylene wax higher than 0 ° C.
005-0.2g / m ² contained in the dye-donor element.