FI65113C - ARMMATERIAL MED MAERKFIGUR OCH FOERFARANDE FOER DESS FRAMSTAELLNING - Google Patents

Abstract

An unobtrusive image is applied to paper or other sheet material by means of a charged droplet printer, for example an ink jet printer. The unobtrusive image applied may perform the function usually associated with a watermark in paper, but in contrast to a watermark, may be applied to papers during their production on high speed wide deckle machines or to coated papers. The method is particularly suitable for unobtrusively imaging pressure sensitive copying material.

Description

1 65113

The present invention relates to a sheet material having a weak character pattern and to a method for producing the same. The material can be provided with a weak character pattern, for example to indicate origin. This invention relates in particular, but not exclusively, to paper sheet material.

10 Watermarks made with a wire roll, and the so-called

false rubber markings made by embossing on a press roll are well known for providing an inconspicuous or faint pattern on paper to indicate its origin.

15 However, watermarks and false watermarks significantly increase the price of paper and are therefore mainly used in high-quality papers, such as high-quality correspondence papers. Watermarks and false watermarks are usually unprofitable in papers with high production speeds and / or made on wide web paper machines. Another problem is that areas of the watermark or false watermark affect some properties of the paper, e.g., density, absorbance, porosity, and smoothness. This can be detrimental in some circumstances, for example if the paper is subsequently coated and a flat surface is desired for the coating. In any case, in the case of coated papers, the use of watermarks and false watermarks is limited by the fact that they may be obscured by the coating. offers the possibility of printing an inconspicuous or faint mark on coated or uncoated paper or other sheet material even in the case of high production speeds or wide webs. Such printing techniques, which include ink-jet printing (also known in Finland as "jet printing", but the name is not established) and electro-static diagrammatic printing, are hereinafter referred to as charged droplet printing techniques. It is known per se. Ink-jet printing is described in an article entitled "Jet Set" in the British Printer, June 1980, and in UK patents 10,354,890, 1,432,366, 1,461,385, 1,462,193, 1,464,370, 1,479,963, 1 491,234, 1,500,908 and 1,533,659.

First, the present invention relates to a sheet material having a weak character pattern printed by printing a charged particle, preferably by ink-jet printing. Secondly, the present invention relates to a method of manufacturing a sheet material with weak markings, characterized in that the pattern is printed on the sheet material using a charged particle printing device, preferably an ink-jet printing device.

20 The sheet material may be, for example, paper or coated paper. In a preferred embodiment of this method, the printing device is mounted on a paper or paper coating machine whose paper or coated paper is produced, wherein the web speed in the printing device is the same as the web speed in the machine. Usually a set of printing equipment is used in the transverse direction of the track.

The marking agent used to provide an inconspicuous or faint mark pattern may be an ink or other material that provides a contrast to the sheet material, for example, a resin or other material that makes the paper sheet material translucent at the point where it is applied.

The invention can be used particularly suitably in connection with a pressure-sensitive recording material, since the recording material is not subjected to pressure during the printing phase (changes in the local properties of the base material caused by water-35 or incorrect watermarking can be

II

3 651 1 3 very harmful to the operation of the pressure-sensitive recording material). The recording material is preferably one in which the labeling takes place as a result of a reaction between two alone colorless reactants. These are brought into contact with each other by means of patterned pressure to form a colored mark. In the most commonly used system as described above, one of the reactants (color former) is in solution in microcapsules that break under pressure, releasing their contents into contact with the other reactant (color developer).

Pressure sensitive storage systems using microcapsules as described above may be self-contained or transfer type. In transfer types, the lower surface of the upper 15 sheets is coated with a microcapsule coating whose microcapsules contain a color-forming solution, and the upper surface of the lower sheet is coated with a color developer. If more than one copy is required, intermediate sheets are used, the upper surfaces of which are coated with a color developer and the lower surfaces with microcapsules containing a color-forming solution. In the self-contained type, one surface of the sheet has a coating composition that contains both microcapsules and a color developer. Alternatively, the microcapsules and the color developer may both be included in the structure of the sheet. As an alternative to the use of microcapsules (except in the latter form), the color-forming solution may be in the form of spheres under pressure in a frangible coating such as gelatin or wax.

This method can be used to print an inconspicuous or faint pattern on either surface of the upper, lower or intermediate sheet of the transfer system described above or the self-contained sheet described above.

The reactants of the pressure sensitive recording material to which the weak character pattern is formed by this method may be conventional, for example, the color formers may be fluorans, phthalides or spirobipyrans and the color developers may be acid clays, phenolic resins or salts of certain aromatic acids. Alternatively, the second reactant may be Ν, Ν'-di-benzyl-di-thiooxamide-5 di and the second nickel cholefone derivative. Since the properties of pressure-sensitive recording materials are already well known and are described very extensively in the patent literature, they will not be discussed in more detail here.

Of course, care must be taken that the ink or other marking material used for the inconspicuous or faint marking pattern does not sensitize the reactants of the pressure-sensitive storage system or otherwise impair the performance of the storage system. The same, of course, applies to other sheet materials and their functional coatings.

15 Although emphasis has been placed here on the use of the invention in pressure-sensitive recording materials, it should be emphasized that the invention may be used in other fields to inform not only the manufacturer's customer but also the purchaser of the final product 20 (e.g. previous products have reached). In this respect, it should be noted that since paper and other similar products reach the end user through printing or other processing step 25, less often directly from the manufacturer, the end user receives the product more usually in the processor's packaging and labeling than the manufacturer.

Examples of other products to which this invention can be applied include heat-sensitive recording material and a variety of printing and writing papers, photographic base paper, automotive air and oil filter papers, and flexible insulating and bonding material.

The invention will now be illustrated by the following examples: 5 6 51 1 3 EXAMPLE 1 Described herein is the use of a static test ink-jet printing apparatus (schematic side view in Figure 1) to produce sheets with a weak mark-5 pattern for use in a pressure sensitive recording system. The device had a nozzle head 1 with one nozzle 2 adapted to emit a color particle jet 5 in a conventional manner. The nozzle 2 was generally placed above the paper support base 3. The substrate was movable in two directions x-y, which were at right angles to each other, and in a direction z which was the direction of the particle jet emission. The movement of the support base (3) was controlled by a perforated strip so that the color particles hitting the paper formed the desired character pattern. The nozzle was about 15 to 75 microns in diameter and had the ability to produce a pulse-shaped color jet. Deflection plates 4 were placed near the nozzle to deflect certain particles from the color particles 5 on paper (only one deflected particle 7 is shown). Collector 6 was placed under nozzle 20 to collect non-deflected color particles.

Arikki clay-coated color developer paper ("Idem '' CF57, supplied by Wiggins Teape) was placed (clay-coated side up) on a backing pad and the machine was used to create a faint character pattern on the sheet. The pulse frequency was 64 KHz, which gave a color particle diameter of about 140 microns, and the deflection voltage was adjusted to obtain the desired deflection angle.

30 The deflection voltage was kept constant so that each deflected particle was deflected by the same amount. The arrangement was such that only about one in a thousand emitted particles was deflected. The path of the deflected particle onto the paper was about 70 mm. It was found that the diameter of the dot formed on the paper-35 was about 400 microns.

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The method was then repeated first with two microcapsule-coated sheets ("Idem" VB56, supplied by Wiggins Teape), in the first case with an uncoated surface facing upwards and in a second with a coated surface facing upwards, and then with two sheets, one surface of each coated with Idem "CFB53, supplied by Wiggins Teape). In the first case, the clay-coated surface was facing up, and in the second, the microcapsule-coated surface was facing up. The desired weak character pattern was obtained in each case. When arranging the sheets to form a pressure-sensitive recording set and using the set in normal use, it was found that the weak character pattern did not interfere with the formation of good and clear copies.

EXAMPLE 2 This describes the use of an ink-jet press in a paper coating machine. The ink-jet printing apparatus described in Example 1 was mounted parallel to the track after the drying apparatus of the coating machine near the vapor current anti-warping apparatus. Support 3 was, of course, not used. A variable deflection voltage was used to deflect the color particles according to the requirements of the desired character pattern. Voltage fluctuations were controlled by perforated tape. A number of coated and uncoated papers were run on the machine at speeds up to 750 m / min, and a successful weak character pattern was obtained each time. It was found that at web speeds as high as 750 m / min, the airflow caused by the web did not affect the trajectory of the particles and thus led to a distortion of the character pattern, and during the rolling phase the color did not stick to the back pepper of the next pepper. Surrounding steam was not found to affect the pattern despite the color being water soluble.

The papers on which the weak patterns were printed were as follows: -2 a) standard 49 gm base paper, similar to that used to make the commercial Idem pressure sensitive recording paper 7 65113.

(b) clay-coated color developer paper ("Idem" CF46, supplied by Wiggins Teape). At some times the coated surface was patterned and at others the uncoated surface.

(c) "Idem" CF46, the surface of which, without a clay coating, is coated with a microcapsule-containing color former and a special protective material (ground cellulose fiber floc) to protect the microcapsules from premature rupture during paper handling and storage (microcapsulation). , where the printing device was installed). At some times a clay-coated surface was patterned and at others a micro-coated surface.

-2 d) a standard 49 gm base paper such as (a), but one surface of which is coated with a microcapsule coating such as (c). At some times the coated surface was patterned and at others the uncoated.

When the printed coated papers described above were assembled into a pressure-sensitive recording set, it performed well.

"Idem" is a registered trademark.

Claims (4)

1. Arkmaterial med en svag märkfigur, känne-t e c k n a t därav, att den är applicerad medelst 30 tryckning med laddade partiklar. A sheet material with a weak character pattern, characterized in that it is printed by printing a charged particle. 2. The material according to claim 1, wherein the ink is used to apply ink-jet printing. The sheet material of claim 1, wherein the weak character pattern is printed by ink-jet printing. 3. The sheet material according to claim 1 or 2, and the sheet material is paper. The sheet material according to claims 1 or 2, wherein the sheet material is paper. A sheet material according to any preceding claim, wherein the sheet material is a pressure sensitive recording material. A method of manufacturing a sheet material having a weak character pattern, characterized in that the pattern is printed on the sheet material using a particle printing device 15 charged. The method of claim 5, wherein the image is printed on the sheet material using an ink-jet printing apparatus. A method according to claims 5 or 6, wherein the sheet material is a paper or coated paper web, and the printing device is mounted on the paper or paper coating machine where the web is made, wherein the web speed through the printing device is the same as the machine web speed. A sheet material made by the method according to any one of claims 5 to 7, having a weak character pattern. 4. The material referred to in the patent is a patented material, which includes an articulated material and printed copying material. (I