JPH0211672A - Ink medium for printer - Google Patents

Abstract

PURPOSE:To obtain the title medium improved in an efficiency of transfer to paper of a low surface smoothness, sharpness of print, etc., by forming a thermoplastic magnetic ink layer containing a binder and at least two specified magnetic powders on the surface of a heat-resistant base. CONSTITUTION:A magnetic powder 3b (e.g., magnetite) is obtained by mixing at least two magnetic powders comprising 1-60wt.% larger-diameter magnetic powder (i) of a BET specific surface area of, desirably, 0.5-4m<2>/g and 20-99wt.% smaller-diameter magnetic powder (ii) of a BET specific surface area of 3-80m<2>/g, said at least two powders having different BET specific surface areas and being used in a ratio of 1:2.20. A thermoplastic magnetic ink layer 3 obtained by dispersing the magnetic powder 3b in a binder 3a (e.g., paraffin wax) is applied to the surface of a heat-resistant base 2 (e.g., polyester film) to obtain an ink medium 1 for printer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an ink medium for a printer used in a method of transferring and recording using magnetic attraction after heating and melting.

<Prior Art> Recently, many non-impact printing methods using magnetic ink have been proposed, and magnetic inks used in these non-impact printing methods have been developed.

As an example of the above-mentioned magnetic ink, for example, JP-A-61-
No. 215088 and Japanese Unexamined Patent Publication No. 63-130387. This ink has a thermoplastic magnetic ink layer containing ferromagnetic fine particles formed on the support layer.

In such ink media for printers, attempts have been made to print by using ferromagnetic particles of magnetic fluid as the ferromagnetic particles of thermoplastic magnetic ink and causing the ink to fly due to magnetic attraction.

<Problem to be solved by the invention> The inventions described in the above-mentioned patent publications both use a printer ink medium in which a single magnetic powder is dispersed, and a comparison of the average particle diameter of several microns is Printer ink media in which large magnetic powder is dispersed can provide large magnetization, but the sedimentation rate of the magnetic powder is high, making it difficult to manufacture printer ink media, or the magnetic powder may absorb the binder agent during transfer. #There was a problem that the transfer efficiency was low because the transfer was performed while remaining on the surface of the thermal base material.

On the other hand, printer ink media in which fine magnetic powder is dispersed have good dispersion stability, but because sufficient magnetization cannot be obtained, transfer cannot be achieved in a short time, making it difficult to perform high-speed printing. The problem was that it required more magnetic energy.

Therefore, the present inventors developed an ink medium for printers in which a magnetic powder with a relatively large particle size of several microns and a small specific surface area and a magnetic powder with a relatively small particle size and a large specific surface area were dispersed. When used, it was discovered that the ink had good dispersibility, the transfer efficiency was high, and the transfer was possible in a short time even with low energy, leading to the completion of the present invention.

The purpose of the present invention is to obtain high transfer efficiency and clear prints at high speed even on paper with low surface smoothness in a method of transferring and recording using magnetic attraction when heated and melted. An object of the present invention is to provide an ink medium for printers that makes it possible. The term "transfer" here refers to printing by adhering the ink on the printer ink medium to the recording paper, and includes cases where the printer ink medium and the recording paper do not need to be in contact with each other.

Means for Solving the Problems> To further specifically explain the present invention, the present invention is an ink medium for a printer comprising a thermoplastic magnetic ink layer provided on the surface of a heat-resistant base material, The plastic magnetic ink layer includes a binder agent and two or more types of magnetic powders having different BET specific surface areas, and the above two types of magnetic powders have a BET specific surface area.
The present invention relates to an ink medium for printers, which has a T-specific surface area ratio of 1:2 to 1:20.

<Example> Hereinafter, an example of the ink medium for printers of the present invention will be described in detail.

FIG. 1 is an enlarged cross-sectional view showing how the ink medium 1 for printers of the present invention is used.

The ink medium 1 of the present invention has a thermoplastic magnetic ink R3 on one side of a heat-resistant base material 2, and a thermoplastic magnetic ink layer 3 formed by a thermal spatula 4 facing the other side of the heat-resistant base material 2. is locally heated and melted, and the heated and melted thermoplastic magnetic ink layer 3 is attracted and transferred onto the recording paper 4 by the magnetic force of the Mizuku magnets 6 facing each other with the recording paper 5 in between. be.

FIG. 2 is an enlarged detailed view of an uninvented ink body I for printers. Basically, a thermoplastic magnetic ink layer 3 is formed on the surface of a heat-resistant base material 2, and the thermoplastic magnetic ink layer 3 is , is composed of a plurality of types of magnetic powders 3b and a binder agent 3a, and the magnetic powder 3b is dispersed within the binder agent 3a.

As the heat-resistant base material 2, for example, a plastic film of polyester, polyethylene, polycarbonate, polyamide, etc. having a thickness of about 1 to 20 p, cellophane, parchment paper, condenser paper, etc. can be used.

The thermoplastic magnetic ink layer 3 formed on the surface of the heat-resistant base material 2 preferably has a thickness of about 2 to 20 JL, and the plasticity temperature of the thermoplastic magnetic ink is preferably in the range of 40 to 200'C. desirable.

The binder agent 3a constituting the thermoplastic magnetic ink layer 3 includes natural waxes such as carnauba wax, candelilla wax, montan wax, beeswax, and lanolin, petroleum waxes such as paraffin wax, microcrystalline wax, oxidized wax, ester wax, Synthetic waxes such as polyethylene wax, higher fatty acids such as lauric acid, stearic acid, myristic acid, palmitic acid, and hehenic acid, higher alcohols such as stearyl alcohol and behenyl alcohol, higher fatty acid esters such as cetyl palmitate and cetyl stearate, and lauryl. Amides such as acid amide, stearic acid amide and oleic acid amide, ester gum, rosin or its derivatives, phenolic resin, terpene resin, xylene resin, polystyrene resin, oil based resin, polyester based resin, epoxy based resin Thermoplastic resins such as resins, polyurethane resins, polyacrylic resins, polyvinyl chloride resins, cellulose resins, polyvinyl alcohol resins, polyamide resins, ethylene vinyl acetate copolymer resins, and ethylene-ethyl acrylate copolymer resins , nitrile rubber, acrylic rubber, styrene-butadiene rubber, natural rubber, and other elastomers, and one or more of these may be used in combination.

Magnetic powder 3 constituting the thermoplastic magnetic ink layer 3 described above
Examples of b include metals of ferromagnetic elements such as iron, corylate, and nickel, alloys containing these elements as main components, and oxides of these elements such as magnetite, γ-hematite, and ferrite.

Among the magnetic powders 3b, the BET specific surface area of the magnetic powder with a large particle size is 0.5 to 4 m2/g, and the BET specific surface area of the magnetic powder with a small particle size is 3 to 80 m2/g, and the ratio is l:
2 to 1:20. The particle size of the magnetic powder 3b described above is B
Magnetic powder with ET specific surface area is 0.5~1oAL, B
The magnetic powder has a small ET specific surface area of 0.01 to 1 l.

In addition, in the case of M of the magnetic powder 3b, 1 to 60% by weight of magnetic powder with a large particle size and 20 to 99% by weight of magnetic powder with a small particle size.
The content of the magnetic powder 3b in the thermoplastic magnetic ink layer 3 is preferably 20 to 90% by weight.

Colorants such as dyes and pigments may be added to the thermoplastic magnetic ink layer 3 to adjust the color density of the ink, but if the magnetic powder is black, dyes and pigments may not be added. You don't have to.

Hereinafter, the ink medium for printers of the present invention will be explained in more detail with reference to Examples.
2 0 (BET specific surface area 2
．． 5m2/g, average particle size 1.2l) Maznedite (//
12 m2/g, // 0,
1 le) 30 paraffinwawagus (mp 6
9℃) 29
carnauba wax
18+1+)-vinyl acetate copolymer (vinyl acetate content 282) 3 Example 2 Mn-Zn7z9ih
l 5 (BET specific surface area 2.5 m2/g, average particle size 1.2 final)zdtL4)
(/l 8.Om'/g, /7 0
．． 2g) 3 5 parafuku 7nwa rqx (mp
69℃)
29Il Lunaba Wax
18 Polyvinyl monoacetate copolymer (vinegar and content 2H) 3 Example 3 Mll-Zll'l Lie)
1 0 (BET specific surface a1.1 m2/g, average particle size 35 islands) Mamudite (t
r 12 m2/g, tr
O, ip) 4 0 Barafinwafukus (mp
69℃)
29 Karnabawa Fukusu
18T-vinyl acetate copolymer (vinyl acetate content 2H) 3 Example 4 Nn-Zn1x94t
2 5 (BET specific surface area 2.5 layers 2/g, average particle size 1.2AL) Marodite (/
/ 11 m2/g, tt 0
．． 1 well) 25 paraffin wax (IMP
69℃) 29
Shikanabawa Tsukuyu
18F-vinyl butyrate copolymer (content 21%) 3 Example 5 Hn-Znlz4t
1 5 (BET specific surface area 1
．． 5m2/g, average particle size 1.8jL) Mac medium tight c
't II m2/g, tt
O, ]g) 3 5 rose in wax (
+ep 69℃)
29 Luna 21 Wax
18 Etilecy Vinyl acetate copolymer (Vinyl acetate containing 2!H)
3 Example 6 7 middle tight
l 0 (BET specific surface M1.2 m2/g, average particle size 2.8 g) magnetite (tt 15 m2/g, tt
0.07g) 4 No. 01 rough-in wax
(IIP 69℃)
29. Urnaba wax
18 Ethylene-vinyl acetate copolymer (vinyl acetate content: 28 $) 3 Example 7 Hn-Zn ferrite
1 5 (BET specific surface area 1
．． la+2/g, average particle size 3.5μ) mappjlq4t(
// 3.0ta2/g, //
0.5 pL) 1 0 n-Zn ferrite

25 (tt )ls2/g, // O,
1g) 21u7/shi7fukus (mp 69℃)
29 Karnabawa Fukusu
18 Ethylene-vinyl acetate copolymer (vinyl acetate content 5.28%) 3 Comparative example 1 Mn-Zn fiber x 94
5 0 (BET specific surface area 2
．． 5m2/g, average particle size 1.2JL) Paraffin wax (mp 69℃)
29h lunaba wax
l 8 ethylene-vinyl acetate copolymer (vinyl acetate content 2H) 3
Comparative example 2 7zunetite
50 (BET specific surface area 1
2■2/g, average particle size 0. IJL) Paraffin wax (mp 69℃)
296 lunaba wax
8-vinyl acetate copolymer (vinyl acetate content i28%)
) 3 Comparative Example 3 Hn-Zn'7xu4t
20 (BET ratio surface i
ll m2/g, average particle size 0.1 uL) Marodite (/
/ 12 rs2/g, //
0.1 body) 30 parafingugusu (tap
69℃)
29 carnauba wax
l 8 Ethylene-vinyl acetate copolymer (vinyl acetate content 128%) 3
Comparative Example 4 Mn-Zn F = 4
1 5 (BET specific surface area 1
．． 1+e2/g, average particle size 3.5l) Mn-Zn ferra 4t
3 5 (tt 2.5m2/g,
tt 1.2g) Paraffin wax (膓p
69℃) 29
h luna power 7 kes
18 Ethylene-vinyl acetate copolymer (vinyl acetate content i28%) 3 Comparative example 5 Mn-Znyx94
1 0 (BET specific surface area 1.1 m2/g, average particle size 3.5 μ) Manedite (/
150 ml/g, // 0.02 l) 40 paraffin wax (P 69℃)
29 Karnabawawakes
l 8 engineering + Ren monovinyl acetate copolymer (vinyl acetate content 2H) 3 (Values for each of the above examples and comparative examples are parts by weight) The ink components of the above individual examples and comparative examples were heated at 100°C. After heating and stirring, the mixture was further uniformly dispersed using a roll mill. The obtained ink was applied to the surface of a polyester film having a thickness of 4μ using a wire bar to obtain an ink medium for printers of the present invention having an ink layer having a thickness of 8μ.

The obtained printer ink medium was used in a recording device that incorporated a permanent magnet with a maximum energy product of 208 GOe in a part of the platen roller of a thermal printer PC-PR201T manufactured by NEC Corporation, and the distance between the recording paper and the ink layer was set at 400 mm.
Printing was carried out at a printing speed of 35 characters/sec.

As recording paper, city-produced PPC paper (Beck smoothness: 40 seconds) and pound paper (Beckk smoothness: 10 seconds) were used.
Clear prints with sharp edges and no blurring were obtained on C paper, and similar prints were obtained on pound paper.

On the other hand, as shown in Table 1 below, none of Comparative Examples 1 to 5 gave satisfactory results for both PPC paper and pound paper.

Table <Effects of the Invention> As explained above, the ink medium for printers of the present invention contains at least two types of magnetic powders with different BET specific surface areas in the thermoplastic magnetic ink layer. When this process is carried out, the magnetic powder with a large BET specific surface area becomes the core, and the magnetic powders with a small BET specific surface area around the core are connected, and the entire ink is melted in a short time with the heat-melted binder agent. Transcribe. Therefore, the ink medium for printers of the present invention is not affected by the surface condition of the recording paper, and has sharp edges and does not fade even on smooth paper such as PPC paper as well as paper with low surface smoothness such as pound paper. Clear printing is possible.

Furthermore, since the ink medium for printers of the present invention allows printing even when the ink medium for printers and the recording paper are not in contact with each other, problems such as background smearing that occur in conventional thermal transfer do not occur.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an enlarged sectional view showing the ink medium for printers of the present invention in use, and FIG. 2 is an enlarged detailed view of the ink medium for printers of the present invention. It is.

Claims (1)

[Claims] An ink medium for a printer comprising a thermoplastic magnetic ink layer provided on the surface of a heat-resistant base material, the thermoplastic magnetic ink layer containing a binder agent and two or more types of magnetic powders having different BET specific surface areas, The ink medium for printers is characterized in that the two types of magnetic powders described above have a BET specific surface area ratio of 1:2 to 1:20.