JPS5911285A - pressure sensitive copying material - Google Patents

Abstract

PURPOSE:To provide a pressure-sensitive transfer material improved in ground contamination without lowering printed density and free from oil bleeding, which is comprised of a film base, an adhesive layer and a special ink layer comprising a resin, an oil, a colorant and a specified pigment. CONSTITUTION:The adhesive layer is provided, as required, on the film base such as a plastic film, then a coating liquid comprising a resin (e.g., a copolymer of vinyl chloride and vinyl acetate), an oil incompatible with the resin (e.g., rape- seed oil), a colorant (e.g., carbon black) and a pigment having a relatively large particle size with a number average particle size of not smaller than 5 (e.g., calcium carbonate) is applied onto the adhesive layer, and the liquid is dried to obtain the objective transfer material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overstrike type pressure-sensitive copying material that does not cause scumming.

In recent years, with the development of high-speed typewriters, word processors, office computers, etc., film-based multi-strike typewriter ribbons have replaced the conventional 7-print ribbon (cloth ribbon) with high print quality, with clear characters and less background stains. Ribbon required. However, with conventional ribbons, when printing, the area around the characters is often smudged, that is, background smearing occurs. Therefore, various methods for preventing scumming have been proposed. For example, it was proposed in 1983 that a thin layer of resin that is incompatible with the ink oil be provided on the ink layer.
Japanese Patent Publication No. 47-51738 discloses that a porous layer is formed by coating an ink layer with a resin solution containing a foaming agent. Further, Japanese Patent Publication No. 47-10779 discloses providing a layer of fine particles of thermoplastic resin on an ink layer. In the first two methods, the holes from which the ink comes out are blocked, which reduces background smearing, but there is a problem in that the print density decreases accordingly. Furthermore, the latter method has a problem in that it is not suitable for multi-purpose trikes because the ink particles peel off once the ink is struck.

The present invention was made in view of the above problem, and includes a pigment with a relatively large particle size in the ink layer, and the surface smoothness of the ink layer is improved by 10 to 100 seconds (as measured by an Oken type smoothness meter).
This goal was achieved by doing so.

An object of the present invention is to improve background smearing without lowering print density. Another object of the present invention is oil bleed (
This is to prevent the ink from oozing out and adhering to the back side of the ribbon if the ribbon pancake is left at high temperatures, causing poor conveyance within the cassette.

According to the present invention, a film is made of a film base material, an adhesive layer provided as necessary on the base material, and an ink layer whose main components are a resin and an oil and a colorant that are poorly compatible with the resin. Furthermore, there is provided a pressure-sensitive copying material in which the ink layer contains a pigment having a relatively large particle size and the surface smoothness of the ink layer is adjusted to 10 to 100 seconds.

Pigments used to adjust the surface smoothness of the ink layer in the present invention include inorganic pigments such as calcium carbonate, silica, clay, alumina, titanium oxide, glass powder, iron oxide, carbon, iron powder, aluminum powder, etc. , and organic pigments such as hardened melamine powder, polyvinyl chloride powder, polyethylene powder, polyacrylonitrile powder, starch, methylcellulose, and various rubber powders.

Not limited to these, any pigment can be used as long as it does not dissolve in the solvent of the ink liquid. It is preferable to use a pigment having a relatively large particle size, with a number average particle size of 5 microns or more, preferably 5 to 20 microns. The surface smoothness of the ink layer is measured using an Oken type smoothness meter and adjusted by selecting the particle size and content of the pigment within 10 to 100 seconds. If the surface smoothness of the ink layer exceeds 100 seconds, it is difficult to obtain the desired effect of the present invention, while if the surface smoothness is less than 10 seconds, the print density will decrease or voids (white spots) may occur in the characters.
may occur. The amount of the pigment used in the present invention is desirably adjusted within the range of 10 to 300% by weight based on the colorant.

The pressure-sensitive copying material of the present invention can be produced by a conventionally known method.

As the film base material, a plastic film having a thickness of about 4 to 20 microns is generally used. For the adhesive layer provided as necessary, apply a solution prepared by dissolving vinyl chloride-vinyl acetate copolymer, linear polyester resin, acrylic resin, etc. in a solvent so that the thickness after drying is approximately O65 to 6μ, and dry. formed by The ink layer is mainly composed of a resin, an oil that is incompatible with the resin, and a colorant, to which a non-exploding pigment is added.When printing, a spacer is added to the ink layer of the transfer paper and ribbon. In addition to preventing background smudges, when the ribbon is reeled, it does not wind up as hard as in conventional ribbons, and even when stored at high temperatures, the ink does not seep out due to capillary action, making the ribbon more durable. The back side is not smeared with ink and transport defects within the cassette are not caused. At this time, it is necessary to prepare the pigment of the present invention by adding the pigment to the dispersed ink liquid afterwards and stirring without dispersing or pulverizing the pigment together with the ink liquid. Conventionally known materials can be used as the material for the ink layer. As the resin, vinyl chloride/vinyl acetate copolymer, polycarbonate, polymethyl methacrylate, polyvinyl butyral, etc. can be used. Further, as the oil, vegetable oils such as rapeseed oil, castor oil, peanut oil, and camellia oil, animal oils such as lanolin, lard tallow, and whale oil, and mineral oils such as spindle oil and liquid paraffin can be used. As the coloring agent, carbon black, iron oxide, alkali blue, cyanine blue, methyl violet, crystal violet, orange red, iozole red, brilliant green, etc. can be used. In addition, wetting agents such as amines and sulfonated vegetable oils may be added. As a solvent for dissolving the resin, methyl ethyl keto/ethyl acetate, methylene toluene chloride, tetrahydrofuran, etc. can be used.

Next, the present invention will be explained in more detail with reference to examples as well as comparative examples, but the present invention is not limited thereto. In the examples, parts are expressed in parts by weight.

Example 1 A 10% solution of polymethyl methacrylate in methyl ethyl ketone was applied to one side of a 7 μm thick polyester film and dried to form an adhesive layer.

The thickness of the adhesive layer was 1.5μ.

Next, lanolin 5 parts rapeseed oil 5# carbon black 4' alkaline blue toner 21VYH)
After dispersing 14' in a ball mill for 24 hours, Rum) was added and dispersed in a homomixer for 5 minutes, and the resulting solution was applied onto the adhesive layer so that the thickness of the ink layer after drying was 15 μm and dried. .

Example 2 Castor oil 10 parts Carbon black 4' Cyanine blue
2' polycarbonate
10'methylene chloride 9
After dispersing 01 in a ball mill for 24 hours, the average particle size was 10.
Two parts of μ silica were added and stirred for 5 minutes using a homomixer.

Example 3 To 100 parts of the ink of Example 1, 5 parts of hardened melamine powder (average particle size 20 μm) was added.

Comparative Example 1 Ribbon 9- was produced in exactly the same manner as in Example 1 except that an ink liquid without Whitener 450 was applied.

Comparative Example 2 A ribbon was prepared in exactly the same manner as in Example 1, except that Whiten÷450 was added from the beginning and dispersed for 24 hours in a ball mill.

Five types of ribbons produced in the above Examples and Comparative Examples were tested for print quality using a Linney printer RP-1600. The results are listed in the table below.

' 2 1.05 Good Very good 75
#' 3 [1,97 Very good Very good
52'' 21.00 Bad Bad 205 10- In the pressure-sensitive copying material of the present invention constructed as described above, the surface of the ink layer is roughened, so the entire ribbon does not adhere to the paper during printing. Therefore, dirt does not occur. In addition, there is little oil bleed after storage at high temperatures, and transportability is good.

Patent applicant: Lico Co., Ltd. -ll- 450-

Claims (1)

[Claims] The ink layer may include a film base material, an adhesive layer provided on the base material as necessary, and an ink layer whose main components are an oil and a colorant that are poorly compatible with the resin and the resin. The ink layer contains a pigment with a relatively large particle size, and the surface smoothness of the ink layer is 10 to 100 seconds.
Pressure sensitive transfer material.