JPS6142638B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A dry pressure-sensitive transfer copying method was previously described in Canadian Patent No. 800319 and US Patent No. 3595683.
Various methods are known, including those disclosed by No. One of the most well-known methods is to form a frangible image that is coated on carbon paper or ribbon and pressed onto a master sheet in mirror image relation to the original image, which is then broken up and transferred to a copy sheet. The invention includes the use of a frangible transfer composition that is continuously transferred onto a copy sheet by being pressed into a copy sheet to form a continuously readable copy image. The number of clear copies that can be obtained is limited to a maximum of 15 or 20, and the images tend to become blurred or smeared when rubbed.

All of the methods described in these patents eliminate the aforementioned problems by providing frangible transfer compositions. That is, when the composition is pressure-transferred to a master sheet, it is not brittle in the pressure-sensitive copying process and is formed of a porous, spongy network of resinous binder material containing the pressure-extrusion ink therein. form an image that can be read. Such master sheets are capable of making relatively large numbers of copies under pressure, and the legible image formed on each copy sheet is absorbed by the surface of the copy sheet, causing blurring and smearing. It has resistance to

A critical drawback of the method described in said patent is the necessity of forming an image on the master sheet by means of an imaging pressure applied to the coated transfer sheet. This involves a first step of coating a transfer sheet or ribbon with an imaging composition that forms a brittle, pressure-sensitive transferable solid layer, followed by contacting the coated transfer sheet or ribbon with a master sheet. It requires applying an imaging pressure to the transferred portion of the solid layer to form an image on the master sheet. Such methods are time-consuming and expensive because only a small amount of the transfer composition is actually used, and sometimes the transfer to the master sheet is performed using a roll press or the like, so the master sheet becomes unnecessary. The imaging composition may be inadvertently transferred to areas and become smudged, especially when used continuously in high speed printing presses.

It is an object of the present invention to provide a novel semi-solid printing ink composition which is clean to the touch, non-staining, and capable of solidifying into a liquid ink-wet image.

Another object of the present invention is to provide a simple and efficient method for quickly producing an imaging master sheet suitable for forming a copy image in a dry pressure sensitive copying process.

Yet another object of the invention is to print an image on a master sheet using said printing ink composition and to apply a fluid ink continuously to a copy sheet under the influence of pressure when said composition is solidified. To provide a method for forming a clean and stain-free master image that can be leached.

These and other objects and advantages of the present invention will become apparent to those skilled in the art from the following disclosure, including the drawings.

That is, FIG. 1 is a schematic enlarged sectional view of a master sheet showing a state in which an image is formed on the master sheet by the pressure copying composition via the stencil sheet. In FIG. 1, the master sheet and stencil sheet are shown spaced apart for convenience of explanation.

FIG. 2 is a schematic enlarged sectional view of a master sheet having a solidified printing pressure copy image.

The objects and advantages of the present invention are to print a master image on a master sheet using a pressure-sensitive copying printing composition, allow it to harden, and then transfer it successively to a copy sheet for making multiple copies. This is accomplished by a method containing a pressure extrusion ink that can be used to form a porous, spongy image that is clean to the touch and does not smudge.

Silk screen printing method uses silk, nylon,
A common name for stencil printing methods that use ink-permeable screens constructed from monofilament or polyfilament threads such as polyester or stainless steel. Most of the screen is treated or masked to make it impermeable to the ink, leaving ink permeable or printed areas corresponding to the image to form the stencil. The stencil screen is placed on the copy sheet and printed, and the printing ink is drawn from the surface of the screen using means such as a rubber roller, passing through the ink-permeable areas and applying the ink to the copy sheet placed on the underside. bring it out. The printed copy sheet is dried to evaporate the volatile vehicle. Such methods can repeatedly produce multiple copies from the same stencil screen by repeating the inking step using multiple new copy sheets.

Typical screen printing inks are prepared by adding ground, highly pigmented colorants to a vehicle consisting of dehydrated castor oil, a compatible synthetic resin, boiled linseed oil and a solvent such as kerosene or solvent naphtha, and are easily To provide a short-running ink that passes through a screen and wets the surface of a copy sheet with a small amount of ink, and allows the screen and the printed copy sheet to be easily separated. The printed image is absorbed into the copy paper and dried on the copy sheet by evaporation of the solvent and binding of the oil and resinous binder.

The pressure sensitive copy printing composition of the present invention is a solvent-based composition having wax and/or resin as the binder material. Such printing compositions are applied to a master sheet with a relatively high deposit in image form so that the composition does not run or migrate on the master sheet, forming a wide or distorted printed image. In any case, it is necessary that it be in a semi-solid state under the conditions of use such that it forms. However, wax-based compositions contain a sufficient amount of volatile vehicle to maintain a semi-solid state throughout the printing operation. On the other hand, resin-based compositions contain a sufficient amount of volatile solvent relative to the resin so that they are semisolid or thixotropic, ie, do not run off in the absence of an external force that can be applied.

The compositions of the present invention include a settable binder material such as a wax and/or resin, a soluble colorant such as a soluble dye, and a non-volatile, substantially immiscible binder material and a solvent for the colorant. In all cases, it is preferred that the ink vehicle is comprised of a liquid, pressure-flow type ink vehicle.

The volatile solvent or vehicle used is one having an evaporation temperature of 93.3°C (200°C) or higher, such as naphtha, mineral spirits, kerosene, toluene, xylene, and the like.
The boiling point is preferably between about 93.3 and 238°C (200 and 460°C). High boiling point solvents are necessary to prevent the solvent composition from drying on the printing screen and sealing the screen due to too rapid evaporation of the volatile solvent.

In the drawings, FIG. 1 shows a silk screen 11 and a conventional master sheet 20 covered with an impermeable masking layer 12, some parts of which are in mirror image relation to the reproduced image. (In FIG. 1, for convenience of explanation, the master sheet 20 and the silk screen 11 are shown spaced apart from each other.)

The semi-solid copying composition 14 is applied to the masking layer 12 using a conventional silk screen squeegee 15.
, a certain part 16 of the composition is forced into the open area 13 and a printed image 21 corresponding to the open area of the stencil sheet 10 is formed on the surface of the master sheet 20 via the silk screen 11.
to form.

The stencil sheet 10 is then carefully peeled from the imaged master sheet 20 and the master sheet is processed to solidify the semi-solid image 21. Such processing is accomplished by drying the master sheet using such means as heat and/or forced circulation of air to evaporate volatile solvents or vehicles from the image.

As shown in FIG. 2, the solid compression image 22 formed on the master sheet is composed of a microporous structure whose skeleton is composed of a binder material such as wax and/or resin, and the binder material is the master sheet. bond to the surface of the sheet,
The pores contain an extrusion type fluid ink consisting of an oily substance that is incompatible with the binder substance and a coloring agent, preferably a small amount of dye dissolved in the oily substance.

According to one embodiment of the invention, the ink vehicle, which is incompatible with the binder materials such as resins and/or waxes and which contains the colorant to form the extrusion type ink, is free from the effects of heating or ultraviolet irradiation. includes or consists of a liquid material that is cured or polymerized to form a solid, durable deposit. Such ink vehicles may consist of any of the conventionally known monomers or prepolymers which can be polymerized under the influence of ultraviolet radiation, such as, for example, pentaerythritol triacrylate, which is commonly used in conventional ultraviolet curable printing inks. Furthermore, as the heat-polymerizable monomer or prepolymer, a heat-polymerizable monomer or prepolymer such as trimethylolpropane triacrylate, which can be suitably used at the temperature used to dry the microporous ink layer, is preferably used. be done. In either case, a small amount of a polymerization inhibitor such as pyrogallol is included to prevent polymerization at room temperature;
It is common to contain a polymerization initiator or catalyst such as 9,10-anthraquinone or lauroyl peroxide to accelerate the polymerization reaction under conditions that allow sufficient irradiation with ultraviolet rays, infrared rays, or other heating means.

According to one embodiment of the present invention, the pressure extrusion type ink comprising a liquid polymerizable monomer or prepolymer and a colorant is such that an image formed on a master sheet is formed under the influence of pressure applied over the entire surface. It exists stably as a pressure-flow type liquid ink at room temperature so that the ink continuously oozes onto the copy sheet. The liquid ink copy image formed on each copy sheet is then produced by polymerization based on the properties of the polymerizable monomer and/or prepolymer, such as ultraviolet or infrared rich light sources, hot air, conductive heat, radio frequency heating, electron bombardment, etc. Processed by exposure to initiating means.

The polymerization reaction makes the image formed on each copy sheet so that the image is durable and non-removable to conventional image stripping correction tapes and/or heating equipment used therewith. Let it harden. This is particularly important from the standpoint of preventing tampering when the photocopy is an important document such as a certificate, paper, check, or other valuable document.

The polymerizable monomer and/or prepolymer is a liquid that acts alone as an ink vehicle or is used in combination with a miscible oily liquid ink vehicle. The solid monomers or prepolymers used are also such that they are soluble in the oily ink vehicle with which they are used. Importantly, the monomers or prepolymers within the ink layer are incompatible with the wax and/or resin spongy material that constitutes the microporous structure within the image on the master sheet as a liquid extrusion type. This means that it must exist in

The surface of the master sheet carrying the pressure sensitive copy image preferably does not absorb ink from the image, which would otherwise reduce the capacity of the image for multiple copies. This is particularly important in the case of imaging master sheets which are made two or three copies at a time and are stored between uses and used at intervals. In that case, if a number of imaging master sheets are stored one on top of the other, or if the sheet is a continuous web rolled into a roll for storage, the back side of the master sheet is also stored in contact with it. It is preferable to prevent ink from being absorbed from the image on the surface of the master sheet.

The master sheet is a registered trademark "Quilon"
and an image-receiving continuous oil such as that obtained from an aqueous emulsion of polyvinylidene chloride resin. Preferably, a barrier layer is used to form the surface of the master sheet. It is highly preferred to use master sheets of plastic film, especially those treated to have an image-receptive surface, such as synthetic plastic film "papers."

The imaging master sheet is pressed so that the imaging surface of the master sheet is pressed against a copy sheet, such as a successively fed paper sheet, which absorbs colored ink extruded from the mirror image of the master image to form a true image. It is suitable for use in making up to 50 copies or more on a conventional pressure copying machine. If necessary, during the copying process, the master sheet and/or )
Heat is applied to the copy sheet.

There are two types of reproduction compositions that utilize volatile vehicles according to the present invention. A preferred type is one containing a thermoplastic synthetic resin soluble in a volatile vehicle, and a second type generally has some of the binder material dissolved in the volatile coating vehicle, but primarily dispersed in the vehicle. It contains pulverized particulate wax or thermoplastic synthetic resin. Preferred compositions are solvent-based and include a small amount of a resinous binder material, substantially incompatible with the binder material, a polymerizable monomer and/or prepolymer, and a small amount of a colorant, preferably an oily material. and large amounts of oily substances containing dyes soluble in. The volatile solvent used is a solvent for binder substances and oily substances and is about 93.3 to 238
It has a boiling point within the range of ℃ (200~460〓).
As such a solvent, water, naphtha, kerosene, methanol-denatured alcohol, toluene, xylene, etc. are preferably used. Binder materials include vinyl chloride-vinyl acetate copolymers, although other resinous binder materials, oil vehicles, and colorants disclosed in the aforementioned U.S. Pat. No. 3,595,683 may also be used.

A second type of composition, a composition containing a particulate binder material dispersed in a volatile vehicle which may also be partially a solvent, is a composition containing a particulate binder material dispersed in a volatile vehicle which may also be partially a solvent. It must be crushed to a fine powder.
The particles are thus smaller than 10 microns for large mesh screens and have a size of less than 5 microns for screens up to 250 meshes in size. This applies to solid materials such as pigments or fillers contained in certain compositions according to the invention. The dispersion vehicle is ~93.3~
It must have a boiling point within the range of 238°C (200-460°) and is an excellent liquid as a solvent for solvent compositions. The dispersion vehicle for these two types of compositions is about 20-40% of the total composition.
Contained in a proportion of Therefore, the solid content is 60 to 80
% to form a semisolid or thixotropic composition that is substantially non-flowing except under the influence of an applied external force.

Dispersible binder substances include carnauba,
Examples include hard waxes such as montane, microstarine, paraffin, and beeswax, and thermoplastic synthetic resins in the form of emulsion, dispersion, latex, and the like. Preferred dispersible resins include polyethylene, polyvinyl acetate, polyacrylate, polyvinylidene chloride, and the like.

Dispersible compositions based on waxes and/or resinous binder materials generally contain large amounts of animal oils,
It contains incompatible oily substances such as vegetable oils, mineral oils, fatty acids such as oleic acid, or fatty acid esters such as butyl stearate, along with small amounts of soluble adhesives.

After passing through the printing step, the dispersible composition is dried by heating to evaporate the volatile vehicle and then preferably coated with wax and/or
Sufficient heat is applied to bond the resin particles to each other and to the master sheet surface.

The amount of heat applied, preferably by exposure to infrared radiation, causes the binder particles to coalesce together and destroys the porosity within the imaging ink layer formed by the spaces between the contacting binder particles. It is considered to be the amount that does not occur. When infrared heating is used, it is preferred to include a small amount of infrared absorbing material, such as carbon black, in the reproduction composition. As mentioned above, if the image formed on the copy sheet contains a polymerizable ink vehicle, the image will be exposed to polymerizing conditions that will harden the image and make it durable.

Next, the solid printing ink composition of the present invention will be explained with reference to Examples. Note that the present invention is not limited only to these Examples.

Example 1 (Ingredients) (Parts by weight) Vinyl chloride-vinyl acetate copolymer 4.5 Polystyrene 6.4 Oleic acid 20.0 Lanolin 3.7 Clay 27.0 Methyl violet dye 6.4 Methyl ethyl ketone 22.0 Toluene 10.0 A resinous binder material is dissolved in a volatile solvent, Oleic acid and dye were then added and stirred to obtain a homogeneous mixture. The mixture was placed in a ball mill, lanolin and clay were added, and stirred for several hours to obtain a semi-solid printing ink suitable for use in the aforementioned printing operations.

Example 2 (Ingredients) (Parts by weight) Montan wax 6.0 Microcrystalline wax 8.0 Carnauba wax 5.0 Ethyl cellulose 6.5 Oleic acid 11.0 Mineral oil 8.0 Lecithin 0.5 Lanolin 4.0 Crystal violet dye 4.0 Clay 18.0 Mineral spirit 29.0 Oleic acid and ethylcellulose were combined in a steam pot. The wax, oil and lecithin were ground in a ball mill along with mineral spirits. The combined oleic acid and ethyl cellulose were then placed in the ball mill and each component was stirred for about 2 hours to obtain a semi-solid printing ink that could be used in the same manner as the ink obtained in Example 1.

Various modifications and improvements may be made within the scope of the claims and such improvements may be used without any difficulty.

[Brief explanation of the drawing]

FIG. 1 is a schematic enlarged sectional view of a master sheet showing a state in which an image is formed by a pressure copy composition on a master sheet via a stencil sheet, and FIG. 2 is a master sheet having a solidified pressure copy image for printing. FIG. 3 is a schematic enlarged sectional view of the sheet. (Main symbols in the drawings), 10: Stencil sheet, 11: Silk screen, 14: Semi-solid copying composition, 20: Master sheet.

Claims (1)

[Claims] 1. A method for producing a master sheet for pressure-sensitive transfer comprising the following steps (a) and (b). (a) an oil-resistant binder material that is a wax, a resin, or a mixture thereof, at least one non-volatile liquid material that is substantially immiscible with the oil-resistant binder material, and that is soluble in the non-volatile liquid material; Colorant and 93.3℃ to 238℃
printing a semi-solid ink composition consisting of a volatile liquid having a boiling point of , and having a substantially non-flowing property at room temperature unless an external force is applied, onto a master sheet in the form of a desired image by means of a screen; (b) solidifying the semi-solid ink composition on the master sheet by evaporating the volatile liquid to form the non-volatile liquid material and the non-volatile liquid material within the pores of the oil-resistant binder material; A step of forming a pressure sensitive transfer ink layer having a microporous structure containing a pressure extrusion type ink consisting of the dissolved colorant.