JPS60110489A - Thermal transfer recording paper and thermal transfer recording apparatus using the same - Google Patents

Abstract

PURPOSE:To enhance the transfer probability of ink, by providing a coating layer on a support as an ink receiving layer and specifying the compositional ratio of the binder of said coating layer to the pigment thereof. CONSTITUTION:A coating layer 34 is provided on base paper such as high grade paper. The ratio of the binder and the pigment for forming said coating laer 34 is specified so as to adjust the binder to 10-50 to 100 of the pigment on a solid basis. A delivered ink ribbon 40 and paper 43 are contacted with a platen roller 48 by an ink ribbon-paper press contacting means 49 constituted of rollers 46, 47 and the platen roller 48 through the ink of the ink ribon 40 and heated by a heating means 50 while the ink ribbon 40 is peeled off from the paper 43 at the point of the roller 47 to perform the transfer of ink.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a thermal transfer recording paper and a thermal transfer recording device using the thermal transfer recording paper, and particularly relates to a thermal transfer recording paper suitable for high-speed color recording and a thermal transfer recording paper using the thermal transfer recording paper. The present invention relates to a thermal transfer recording device used.

[Technical Background of the Invention and Problems Therewith] Thermal transfer recording devices, which have the advantages of no maintenance, *-r, and low noise, are attracting attention among office automation systems.

This thermal transfer recording device is based on the principle of forming a recorded image by thermally transferring ink, and therefore has a very simple structure. However, because the principle is simple, the accuracy of ink transfer does not have a significant effect on the quality of recorded images.

However, when thermal transfer recording is performed at high speed, as shown in Figure 1 (
A missing pixel 1o occurs as shown in a), or when color recording is performed by overlapping multiple inks, a missing pixel 11 occurs as shown in FIG. 1(b). It happened. Furthermore, in high-resolution recording, the above-mentioned problem becomes more pronounced, resulting in the problem that a single character lacks sharpness and color unevenness occurs in a color image.

[Object of the Invention] It is an object of the present invention to eliminate the above-mentioned drawbacks and provide a thermal transfer recording paper with a higher probability of ink transfer.

At the same time, it is an object of the present invention to provide a thermal transfer recording device that produces high quality recorded images.

[Summary of the Invention] In the thermal transfer recording method, the setting of ink on paper remains on the surface of the paper. This is because the ink heating time is generally short, so the time it takes for the ink to become flowable is shorter.
This is because the time taken to penetrate the paper is shorter. After this setting, dots are formed by separating the ink ribbon from the paper, so the degree of adhesion of the ink to the paper and the strength of the adhesion are key points in determining the quality of the dots.

The various factors governing these will be explained using FIG. When the paper surface is smooth (Fig. 2 (a)), under proper heating conditions, the ink will adhere to the paper 21 in the adhesion area Z, which has an almost one-to-one relationship with the heating area η, but the ink carrier If the surface characteristics of the film and paper are similar, the probability of transfer is 50%, and stable dot formation is not guaranteed. Also, if the surface roughness of the paper is large (see Figure 2)
b)) The ink is applied only to some places on the paper 21, as shown by the adhesion areas, and no image dots corresponding to the heated areas 22 are formed. In addition, if the paper 21 is poorly wetted with ink (see Fig. 2 (C)), the adhesion area Z5
Even if it is secured, the strength of adhesion will be weakened, or there will be some areas where no adhesion will occur, and similarly it will be difficult to form dots in accordance with the heating area B.

That is, the characteristics required of recording paper for thermal transfer recording are not just the smoothness of the paper surface. What is truly required is true contact of the ink with the recording paper and ensuring a sufficient contact area. To be more precise, the determining factors are different between the case of contact between solid ink and recording paper and the case of contact between at least molten ink and recording paper. Consideration is necessary.

The present invention was made from the above-mentioned viewpoints, that is, to secure an adhesion area according to the heating area and to improve the adhesion strength. The composition ratio (solid content) of the pigment and binder in the layer is limited to 100% of the pigment and 50% of the binder. Furthermore, even better effects have been found by using pigments with an average particle size of 0.5 μm or less. Furthermore, a thermal transfer recording device compatible with high speed and color printing is constructed using the recording paper of the present invention as a component.

[Effects of the Invention] With the thermal transfer recording paper of the present invention, even high-resolution pixels can be formed clearly and with sufficient image density, thereby eliminating missing or missing pixels. In addition, it is possible to form dots with less thermal energy than conventional methods.

Furthermore, by using the thermal transfer recording paper of the present invention, a thermal transfer recording apparatus that outputs recorded images with high speed, high resolution, and high density can be obtained. Furthermore, a thermal transfer recording device that outputs color recorded images with excellent color reproducibility can be obtained. Furthermore, a thermal transfer recording device that saves energy and is highly economical can be achieved. Furthermore, a thermal transfer recording device can be provided which can be used for both an ink adhesive type thermal transfer recording method in which ink is melted or made sticky and adhered to paper, and an ink sublimation type transfer recording method in which ink is sublimated and adhered to paper.

[Embodiments of the Invention] A thermal transfer recording paper according to the present invention and a thermal transfer recording apparatus using the same will be described in detail with reference to the drawings. FIG. 3 shows the structure of the thermal transfer recording paper according to the present invention.

A coating layer containing a pigment 32 and a binder okara is provided on the surface of the base paper 31. Base paper 31 generally includes NBKP,
Bleached chemical pulp such as LBKP, NB8P, LB8P, mechanical pulp such as GP, RGP, TMP fi, semi-chemical pulp, chemical ground pulp, etc., appropriately sized or unsized medium-quality paper, wood-free paper, or polyester, polystyrene. A thermoplastic resin film or synthetic paper such as, for example, can be used, but the composition of the base paper itself is not particularly limited. Alternatively, a base paper smoothed by a supercalender or the like may be used.

As the pigment 32, acicular inorganic pigments such as acicular light calcium carbonate, preferably having an average major axis of less than 0.5 μm, or powdered urea formaldehyde resin, powdered polystyrene resin, etc., preferably having an average particle size of 0.5 μm are used. Particulate synthetic resins with an average particle size of less than 0.5μ, or synthetic silicas such as natural or white carbon, clays, talc, aluminum sulfate, nitrogen dioxide, zinc oxide, etc., can be used, preferably with an average particle size of less than 0. Synthetic silica such as white carbon of .1 μm or less, and inorganic pigments such as light or heavy calcium carbonate can be used.

The pigments used in the present invention are inorganic pigments and granular synthetic resins with the above-mentioned shapes and particle sizes, but if these specific pigments are contained as pigment components in an amount of 30% or more, other pigments with shapes other than the above may be used. , may be used in combination with pigments of particle size. Also,
Treatment of inorganic pigments with nonionic, cationic, or amphoteric activators such as funnel oil, sodium dodecyl sulfate, organic amines, metal soaps, and sodium lignin sulfonate improves wetting of the ink ribbon with the ink, making it suitable. Can be used for

Vine f33 is styrene-butadiene rubber (88B)
Rubber-based materials such as nitrile rubber (NBR), vinyl chloride-
Vinyl acetate copolymer, acrylic resin, methacrylic resin,
Adhesives made of water-insoluble polymers such as urethane resin, vinyl acetate-ethylene copolymer, ethyl cellulose, petroleum resin, etc., or vegetable waxes such as carnauba wax and book wax, and animal waxes such as beeswax and Serratus wax. , petroleum waxes such as microcrystalline wax and paraffin wax, and solid waxes such as synthetic waxes such as oxidized waxes and ester waxes.

As an adhesive, the requirements are film-forming properties and a small, preferably 40
The surface energy should be greater than d yn/clft. The ratio of solid wax to adhesive is 5-50
H, preferably 5 to 25%. This means that if it is less than 5%, the effect of wax combination will be lost, and if it is more than 50qb,
This is because problems arise in film formability. The ratio of the pigment 32 and the binder 330 forming the coating layer is 10 to 50 parts of the binder to 100 parts of the pigment in terms of solid content, as shown in the examples. Preferably, the amount is 15 to 40 per 100 of the pigment. The coating liquid that forms the coating layer 34 includes various auxiliary agents, agents for making the coating layer waterproof, fluidity improvers during coating, gloss finishing agents, preservatives, antifoaming agents, dyes, etc. The coating layer can be formed by a conventional coating machine such as a blade coater, air knife coater, roll coater, or bar coater, or by a size press, a gate roll device, or the like. Furthermore, since the surface of paper with only a coating layer is poor in smoothness and uniformity, after coating and drying, it is compressed using a super calender or the like to adjust the smoothness. The thermal transfer recording paper according to the present invention has a Beck smoothness of 300 seconds or more and 2500 seconds or less, an average surface roughness of 0.5 μ or more and 5 μ or less, preferably a Beck smoothness of 500 seconds or more and 2000 seconds, and an average surface roughness of 1 μ or less and 3 μ or less. It has surface properties of

This is because if the Bekk smoothness is less than 300 seconds and the average surface roughness is more than 5μ, the ink will not come into contact with the paper uniformly, or the dots will be chipped. In many cases, the adhesion is insufficient and the ink is not transferred. This is particularly likely to occur when the paper surface becomes uneven due to previously transferred inks, such as in a color thermal transfer recording device that creates a color image by sequentially transferring a plurality of inks onto paper.

Next, FIG. 4 shows the basic configuration of the thermal transfer recording apparatus according to the present invention. The ink ribbon 4o is an ink ribbon supply reel 41
The ink ribbon is fed out by the ink ribbon supply roller 42. The paper 43 is fed out from a paper supply reel 44 by an ink ribbon supply roller 45 .

The fed-out ink ribbon 40 and paper 43 are moved to a roller 46
The ink ribbon is pressed onto the platen roller 48 via the ink (not shown) of the ink ribbon by an ink ribbon-sheet pressure contact means 49 composed of an ink ribbon and a platen roller.

The ink ribbon mallet in the press-contact state is heated from the side opposite to the paper 43 by a driving circuit (not shown) between heating means that selectively generates heat in time and space according to recorded information. . The heating means can be in contact or non-contact with the dielectric, depending on its specific method. After the heating recording, the ink ribbon is removed from the paper 43 at the point of the roller 47 by the drive of the ink ribbon discharge port roller 51.
Then, the ink is transferred. The paper 43 is discharged to the outside of the apparatus by the paper discharge roller 52. Through this series of processes, thermal transfer recording is completed.

In the case of color printing, this process is repeated depending on the number of colors, although paper and ink ribbon conveyance control differs depending on whether plane sequential printing or line sequential printing. Ink Ribo 740 is 4~20μ
Resin films such as polyester, base films such as paper such as condenser paper, solid waxes such as carnauba wax and paraffin wax, low molecular weight polyethylene, and petroleum resins with melting points of 65 to 150'O and easily meltable under heat. Adhesives made of resins, etc., include pigments and dyes commonly used in the printing field such as carbon black and phthalonanine blue, or dispersed monoazo dyes, dispersed anthraquinone dyes, and anthracene dyes with a sublimation temperature of 65 to 200°C. An ink that is solid at room temperature and containing a sublimable dye dispersed therein is applied at a coating amount of 2 to 20 g/m2. In addition, the form of ink application is a single color ribbon, a color ink ribbon in which multiple ink layers of different colors for one screen are repeatedly provided in the longitudinal direction, or a color ink ribbon in which color ink areas are divided in the longitudinal direction. There is,
Ribbon width and length can also be determined arbitrarily. Paper 43 is the paper according to the present invention. It can be used in the form of roll paper, cut paper, etc.

Between the heating means, a moving head type thermal head, a line head type thermal head, a laser beam such as a C02 laser or an Ar laser, a thermal wire, a thermal matrix type, etc. can be used. When the platen roller can be heated without contact, such as a thermal head, it is preferably made of an elastic material such as silicone rubber so that the thermal head and the ink ribbon paper can be brought under appropriate pressure conditions. Further, it is preferable that the ink ribbon and the paper move as one between the heating recording point and the peeling point.

Next, a description will be given of the recording results obtained when the apparatus configured as described above is operated. The performance of the thermal transfer recording paper in this example was evaluated as follows using an evaluation device equipped with a thermal head having a heating element density of 12 dots/IIIm and recording images at a resolution of 12 dots/mz in both the horizontal and vertical directions. The following four items were examined. The recording conditions such as the recording voltage and the applied pulse width were kept constant except for the ink ribbons 1 and 4.
In No. 2 and No. 4, a black ink ribbon with the same specifications was used, and in No. 3, a color ink ribbon with the same specifications was used.

1. Transfer probability: A pixel consisting of 2 dots x 2 dots is set to paper feed speed 2.
Recording was made at a speed of 5 m/min, the number of objects with a regular pixel size of 7 A or more was observed, and the percentage of the number of objects observed was calculated.

2.Resolution characteristic A: A checkered pattern with side length n was recorded with n=1.2, 3, and 4.6 (corresponding to resolutions of 12, 6, 4, and 3.2 dots/square, respectively). The transfer density was measured using a Macbeth densitometer RD-2, and the maximum resolution was determined in an area of equal density.

3. Resolution characteristic B: Record the first color by changing the checkered pattern with side length n to n = 1, 2, ... (each corresponding to a resolution of 12.6 dots/I11), After recording in the second color on the empty part of the checkered pattern, the dots of the second color were observed under magnification, and the shape of the dots was evaluated in three grades: A, B, and C. Those that are close to square are rated A, those with slight chips are rated B, and those with significant chips are rated C.

4. High-speed recording performance: Transfer probability evaluation pattern recording at paper feeding speed of 250 cmZ
The transcription probability was calculated using the same evaluation criteria as the transcription probability of 1.

[Evaluation Example 1] 15 parts by weight of talc and 2 parts by weight of aluminum sulfate were added to a mixed valve slurry of 1 part by weight of beaten LBKP 80 weight and 20 parts by weight of NBKP, and paper was made by a conventional method using a Fourdrinier paper machine.
Size press with oxidized starch, 70g/meter tsubo
I made the base paper for fn.

To 100 parts by weight (solid content) of a slurry of acicular light calcium carbonate with an average particle size of 0.3μ, 10.15.2 parts by weight of styrene and butadiene latex solution, 30, 40.50 parts by weight (
solid content) to prepare five types of paints. These paints were applied onto the base paper using an air knife coater in a coating amount of 12 g/m2 on one side, and after drying, they were passed through a super calender to obtain recording paper (Nos. 11 to 6). solution to 5,60
Comparative papers (1) and (2) were obtained by adjusting the paint in parts by weight (solid content) and performing the same process as the above recording paper. Table 1 shows the coating layer composition and evaluation results of these papers. The Bekk smoothness and average surface roughness of the ink-receiving surface of each paper are also listed.

As is clear from Table M1, all of the recording papers according to the present invention exhibit a high transfer probability, and are excellent in transfer characteristics during multiple printing and high-speed recording performance, especially in the Ba-Ingu ratio (
Recording papers with a solid content ratio of 15 to 40 for a pigment of 100 exhibit excellent characteristics of high resolution and high speed (1/C). Due to the lack of binder in comparison paper (1), fine sharpness occurs in the coating layer, deteriorating the resolution characteristics, and in comparison paper (2), the grip characteristics against the feed roller etc. during paper transport are poor. A trend was observed.

The following margin [Evaluation Example 2] 100 parts by weight of beaten LBKP was used as raw material pulp,
After adding 10 parts by weight of talc and 2 parts by weight of aluminum sulfate, paper was made using a fourdrinier paper machine in a conventional manner, and size pressing was performed using oxidized starch to produce a base paper with a weight of 50 g'Δ-.

IJ - 100 parts by weight of each pigment of heavy calcium carbonate with an average particle size of 3 μm, light calcium carbonate with an average particle size of 1 μm, light calcium carbonate with an average particle size of 0.5 μm, and synthetic silica with an average particle size of 0.03 μm ( 15.Styrene-butadiene latex solution (solid content). ．． Eight types of paints were prepared by mixing 30 parts by weight (solid content). These paints are applied onto the base paper using an air knife coater so that the coating amount on one side is Bg/ln'', and after drying, the recording paper is coated through a super calender (
(8) was obtained. In addition, as a comparative example, four types of paints were prepared by mixing 100 parts by weight (solid content) of Slur IJ of each of the above pigments and 5 parts by weight (solid content) of a tostyrene-butadiene latex solution, and comparisons were made in the same manner as in the examples. Paper (1) ~
(4) was obtained. Table 2 shows the coating layer composition and evaluation results of these papers.

The Bekk smoothness and average surface roughness of the ink-receiving surface of each paper are also listed.

As is clear from Table 2, even if the type of pigment in the coating layer is changed, any binder with a solid content ratio of 5 to 100 parts of pigment is not suitable for thermal transfer recording paper. Furthermore, recording paper using pigments with a particle size of 0.5 μm or less showed a high transfer probability and good dot shape. Especially the average particle size is 0.
．． The recording paper using synthetic silica of 0.3 μm as a pigment provided good dot shapes even in high resolution patterns.

Margin lc4 [Evaluation Example 3] An embodiment of the thermal transfer color recording apparatus according to the present invention using the recording paper 7 of Evaluation Example 2 will be described with reference to FIG. 5. 1
A thermal head 53 with 2,624 resistive elements arranged in one row and a thermal head 53 supported by 7
A recording head assembly 56 consisting of a supporting plate 54 and an ink ribbon peeling roller 55 attached to the supporting plate 54 is disposed opposite to the recording head assembly 56 by the action of a spring 57 and an electromagnetic lever 58, and is driven by a step motor (Fig. (not shown), it can be in contact with or separated from a silicone rubber ruler 59 having a rubber hardness (JI8 hardness) of 40, which rotates at a predetermined paper feeding speed. A four-color ink ribbon 60 with a width of 210B and on which inks of four colors of yellow, magenta, cyan, and black appear repeatedly at a pitch of 297 m in the longitudinal direction is guided by an ink ribbon supply roll 61 to guide rollers 62 and 63, and is then fed to a recording head. Assembly 56 and platen roller 59
The ink ribbon passes through the separation roller 55 and the guide roller 64, and is then wound onto a take-up roll 65 driven by a motor (not shown).

The recording paper 66 is fed out from the recording paper supply roll 67 and is fed between the recording paper pressure roller 68 and the platen roller 59 in close contact with the circumferential surface of the platen roller 59.

Next, the recording operation of the apparatus will be explained. When a start signal is input, yellow ink is detected by the ink ribbon sensor 69, and the ink ribbon sensor 69 is set so that its leading end is located at the position of the heating element array of the thermal head 530. At this time, the recording head assembly 56 is separated from the platen roller 59, and only the ink ribbon 60 is transported by the drive of the ink ribbon take-up roll 65. Thereafter, the recording head assembly 56 is lowered, the thermal head 53, the ink ribbon ω, the recording paper 66, and the platen roller 59 are brought into pressure contact, and the recording preparation is completed.

The drive circuit (not shown) of the thermal head 53 is driven by a recording signal corresponding to yellow recording from a recording information source (not shown), and the heating element has a pulse width of 1 m5 (maximum) and a pulse/l/span. It selectively generates heat with a cycle of 2 ms and an exothermic energy of 7 omJ/III+2. Since this thermal head 53 is capable of driving all heating elements, the rotation of the platen roller 59 causes the ink ribbon 6 to be
0, the recording paper 66 is conveyed without shifting. Further, the driving of the thermal head 53 is controlled so that the heat generation temperature of the heating element remains constant regardless of the amount of recording signal. The partially adhered ink ribbon 60 and recording paper 66 are separated by a peeling roller 55, and the ink is transferred to the recording paper. At this time, the ink ribbon 60 is stretched by the drive of the ink ribbon take-up roll 65 to prevent the ink ribbon 60 from fluttering, which may cause transfer defects. In this way, one screen is first recorded using yellow ink. During this time, the ink ribbon 60 and the recording paper 66 are transported at a constant speed.

After the yellow recording is completed, the recording head assembly 56 is separated from the platen roller 59. The recording paper 66 causes a step motor connected to the platen roller 59 to rotate in reverse at double speed. By moving the recording paper 66 backward by the same number of forward steps, the recording paper 66 is set at the initial position. During this time, magenta ink is set on the ink ribbon 60 by driving the ink ribbon winding roll 65. After the ink ribbon 60 and recording paper 66 are set, the recording head assembly 56 is lowered, and the thermal head 53, ink ribbon 60, recording paper 66, and platen roller 59 are brought into pressure contact again, and preparation for magenta recording is completed. Similar to yellow recording, the thermal head 53 is driven by a recording signal corresponding to magenta recording from a recording information source (not shown), and magenta ink recording is superimposed on yellow recording.

Similarly, cyan recording and black recording are performed. With this recording device, a high-speed color thermal transfer recording device capable of outputting an A4 size full-color image with a resolution of 12 dots/Im in about 40 seconds was created. The resulting image was an excellent full-color image with clear dots and excellent gradation, with no missing or missing dots.

On the other hand, in the color thermal transfer recording device configured using Comparative Paper 2 of Example 1 and Comparative Paper (5) of Evaluation Example 2, color images with a very rough feel and poor gradation due to missing dots were obtained. Although the embodiments of the present invention have been described above in detail, the present invention is not limited to the above embodiments.

For example, the thermal transfer recording method is not particularly limited as long as it uses heat to change the ink on the ink carrier into a state such as melting, fluidization, sublimation, or evaporation.

Thus, the present invention includes any modifications as long as they do not depart from the spirit of the invention.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the problem of image dot formation in thermal transfer recording, Figure 2 is a diagram for explaining the relationship between the surface characteristics of recording paper and ink transfer, and Figure 3 is an example of an embodiment of the present invention. FIG. 4 is a diagram illustrating the configuration of a recording paper according to an example. FIG. 4 is a diagram illustrating the configuration of a thermal transfer recording device according to an embodiment. FIG. 5 is a diagram schematically showing a color thermal transfer recording device according to an embodiment. It is. 31...Base paper, 32...Pigment, O...Binder,
Tone: Coating layer 1, Xun: Ink ribbon, 43, 6
6... Recording paper, source... Heating source, 5; 3... Thermal head, I... Platen roller, 60... Color ink ribbon. Dimension 1 Miri 7~ Bird

Claims (4)

[Claims] (1) A thermal transfer recording paper in which a coating layer consisting of a pigment and a binder is provided as an ink-receiving layer on a base, and the coating layer has a solid content ratio of 100 parts of the pigment to 1 part of the binder.
A thermal transfer recording paper characterized by having a grade of O to (equity). (2) The thermal transfer recording paper according to claim 1, wherein the pigment has an average particle size of 0.5 μm or less. (3) Recording paper on which a coating layer containing 100 parts of pigment to 10 parts of binder is provided on the substrate, and the ink to be transferred to the coating layer of this recording paper. A thermal transfer recording device comprising an ink carrier and a heating means for selectively applying heat to the ink carrier. (4) The thermal transfer recording device according to claim 3, wherein the pigment has an average particle size of 0.5 μm or less.