US2100436A - Printing - Google Patents

Description

Nov. 30, 1937. w. H. ENGEL 2,100,436

PRINTING Filed March 1, 1937 Patented Nov, 30, 1 937 UNITED STATES PRINTING William H. Engel, Mount Vernon, -hio, assignor to Shellmar Products .Ohio,

Application March 1,

3 Claim The present invention relates to an improved process for printing materials such as Cellophane in which the web to be decorated is of a nonadsorbent character, and has particular reference to a method for preventing offset or smearing of freshly deposited ink.

A principal object of the invention is the provision of a process for preventing offset in a freshly printed web by depositing relatively finely divided particles of an iron-containing material on the freshly deposited ink, drying the ink, and subsequently removing the particles by means of magnetic attraction.

A further object is an improved method of preventing oflset in connection with a freshly printed web in which the printed web is rolled up withrelatively finely divided loose particles which may contact the ink during the drying period to space the ink from the adjacent layer of the rolled web.

Still another object of the invention is to provide an improved process for printing materials of the type described without the necessity of using slip sheets.

These and other objects will be observed upon a consideration of the following description of the invention and by reference to the accompanying drawing, in which Fig. 1 is a somewhat diagrammatic view of apparatus for applying finely divided particles of a ferrous metal to a freshly printed web; and

Fig. 2 is a'diagrammatic view of apparatus for removing the finely divided particles from the web after the same has dried.

Transparent regenerated cellulose and materials of this general character afford a nonfibrous structure which makes the use of relatively slow-drying inks a matter of some difllculty in connection with the printing of the materials. When regenerated cellulose, cellulose acetate or the like are printed with oil base inks or the like several hours time is required for the Company, Mount Vernon,

a corporation of Delaware 1937, Serial No. 128,336

paper breaks are apt to slow down process.

In accordance with the present invention the freshly printed web of Cellophane has deposited on it a quantity of finely divided magnetic metal particles which may be imbedded to some extent in the wet ink. The printed Cellophane is then rerolled with these loose particles which space the freshly printed web from the next adjacent convolution thereof. After the ink has hadtime to dry the Cellophane is unrolled and the particles of metal are removed by magnetic means. .As shown in Fig. 1, the hopper l0 contains a supply of finely divided particles of steel. At the base of the hopper I0 is a roller II which supplies 5 a quantity of finely divided steel particles to the traveling magnetic belt l2. The belt l2 rotates in the' direction shown in the arrow and picks up a layer of steel particles. The magnetic belt I! may be relatively weak and as the particles on the belt I! contact with the belt l3 transfer of the particles is made to the latter, since the belt I! is magnetized to a greater extent than the belt II. The magnetic belt l3 travels in'a direction shown in the arrow and carries a layer of the steel particles adjacent a traveling web ll of freshly printed Cellophane. The web It may come directly from the press and is wound into a roll indicated at l5. Between the roller 16 and the roll I5 is positioned an electromagnet ll of greater strength than the magnetic belt l3. Magnet I] is positioned adjacent the path of travel of the particles on the belt l3 and causes these particles to be transferred from the belt to the face of the Cellophane, thereby forming a somewhat even layer of particles throughout the area of the printed side of the Cellophane. The magnet Il may extend downwardly to a point adjacent the roll l5 so that the even distribution of the particles is maintained until a web is wound into a roll which will hold the particles against slippage.

The magnetic particles may be selected as of a size most suitable for the particular printing ink and surface to be covered. When the parti- 5 cles contact the freshly printed web they may imbed themselves to some extent in the wet ink. Theroll I5 is allowed to dry in the usual manner customary with the use of sandpaper until the ink has dried. Thereafter the roll I 5 is unwound and the printed side thereof is passed adjacent one or more strong electromagnets. A first electromagnet is indicated at I 8 as consisting of a belt which may travel in substantially the same speed as the speed of the web so as to avoid the possithe printing bility of scratching. The magnetic particles are removed from the printed surface of the Cellopbane at this point and are transferred to the magnetic belt. The particles then may be scraped or otherwise removed from the belt after it has left the proximity of the printed sheet so as to present a clean surface to the printed sheet as the belt revolves. A second electromagnetic belt is indicated at l8 and the function of this second belt is to remove any magnetic particles which have escaped from the magnetic belt |8. This belt is similar to belt l8 and may travel in the same direction as the web M at substantially the same speed to prevent scratching. Particles may be removed from the belt l9 adjacent its lower position so as to present a clean surface to the printed sheet. A pan or other suitable receptacle 2!! may be provided adjacent the roll 15 to catch particles falling from the web ll as it leaves the roll. One or more magnets such as shown at 2| may be provided as desired to remove any of the steel particles which may adhere to the unprinted side of the Cellophane. The particles accumulating and adhering to the magnet 2| may be removed in any suitable manner.

After the web l4 passes the second magnet I9 it is again wound into roll form as shown at 22. If desired, the roll may be cut into sheets.

By proceeding in the manner described, it is not necessary to adhere the particles to a P per web as is done in the case of sandpaper and the use of magnetic means as described provides for good distribution of the particles and control of their deposit and removal from the printed web. The particles are readily removed from those portions of the web which are not printed and by employing magnets l8 and IQ of suiilcie'nt strength. The particles are removed from their imbedded position in the inked portions of the sheet. In employing this type of printing it is preferred to print the design in reverse on the under side of the Cellophane.

It will be understood that the mechanism shown in the drawing for depositing and removing the particles of magnetic metal may be varied to a wide extent. The feed roller ll may be provided with depressed portions to assist in removing the proper amount of metallic articles in the hopper. A single magnetic belt such as shown at I! may be employed for depositing the particles on the web. The application of the magnetic metal may be made by sifting devices which do not depend upon a magnetic application. One or more stationary electromagnets may be employed for removing the particles from the web II as the latter is unrolled, as shown in Fig. 2. --A nonmagnetic scraper can be used for removing the particles from the magnets l8 and or from a stationary magnet 2|. Brushing and wiping mechanisms likewise may be utilized to assist in the removal of particles.

After the particles are removed from the printed web as shown in Fig. 2 it is preferred that they be washed in a bath of a suitable solvent which .will remove any adherent ink. Thereafter the particles are dried and replaced in the hopper Ill.

The particles may vary to some extent in their chemical and physical characteristics. To prevent deterioration by rust and the like, it is preferred to use stainless steel particles. The amount of the particles deposited onJthe paper will depend upon such factors as the amount of ink deposited on the web. All of these features are subject to considerable variation and the many changes which are possible from the disclosure hereof are intended tobe included in the appended claims.

I claim:

1. The process of printing a web, which comprises depositing a wet ink on the surface of the web, depositing particles of a magnetic metal on the printed web, drying the ink, and magnetically removing the particles of metal. a

2. The process of printing a web, which comprises printing said web with a relatively slowdrying ink, depositing particles of a magnetic'

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