US1750754A - Hectograph blanket - Google Patents

Description

March 18, 1930. w. HosKlNs, JR

HECTOGRAPH BLANKET Filed July 2, 1928 Patented Mu. ,18, 1930 UNITED STATES PATENT OFFICE WILLIAM HOSXINS, JR., 0F CHICAGO, IITLIII'OISJ, ASSIGNOR TO DITTO INCORPORATED,

OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS HECTOGRAPH BLANKET Application filed July 2,

This invention relates to hectograph sheets or blankets or similar means which embody the same characteristic principles of operation.

The principal object of the present invention is to provide a hectograph sheet or blanket having the customary coating of suitable material for the absorption of ink, which will produce a large number of good coples, will not harden or dry out and which is substantially opaque whereby the ink absorbed inwardly from the surface renders it visibly clean.

The use of hectograph sheets or blankets is well known for reproducing copies of typed, written or other like matter, and is known to involve the use of a coating usually of a mixture of glue and glycerin applied on a backing sheet. The written matter to be reproduced is produced originally in a special kind of ink adapted for this use which 1s absorbed by and maintained on the surface of the glue and glycerin coating when the sheet is pressed in contact therewith. Relatlvely large numbers of copies may be made by placing additional sheets in contact with the blanket which gives up the ink to produce reproductions of the original thereon.

After periods of standing the glue-glycerin coating possesses a characteristic of absorbing the ink inwardly from the surface whereby the surface is' rendered clean and fresh and capable of reuse for producing additional and different copies.

In order to produce good copies it is found desirable, after the original has been oset on to the glue-glycerin blanket, to ascertain by inspection the quality of the offset, that is to make sure that the copy has been accurately transferred and is in proper condition to take additional copies from. It is also found, however, that the ink which .has been absorbed inwardly of the surface as occasioned by former use of the blanket becomes diiused throughout the volume of the coating material, and due to the transparent nature of the glue-glycerin coating, is readily visible presenting a background similar in color to that of the ink employed. The presence of the ink v colored background renders it very diiiicult 1928. Serial No. 290,037.

because the absorbed inkilickly forms the background against whic contrast can be made.

no substantial It has been found desirable,therefore, to

incorporate Ain the blanket ,coating material, a pigment whichwill have suicient hiding power to render the blanket substantially opaque and of such contrasting color that the freshly inked surface will be readilyv detectable upon inspection. This involves considerable difficulty, however, on account of the fact that many pigments or inert powdered substances which might be employed for this purpose tend to dilute the ink absorbing medium with a consequent diminishin of the eiect and functiomng of the blanet, and further tend to render the coating short or crumbly in character and to cause premature dr ing or hardening thereof.

t has been only through long experimenting that a substance having the desirable properties has been found, that is, having such high hiding power that it will produce a coating substantially opaque when employed in quantities proportionall so small that its presence has substantia ly no eiiect on the properties of the blanket.

The present invention accordingly involves the use'of titanium oxide which is a white inert powdered substance having an extremely high hiding power. Titanium oxide is found in practice to produce white blankets f troduction of the titanium oxide by any desited method, it being found well in practice to mix it in with the glue-glycerin composition by the use of mixing ro s, it being found that the pulverizing and mixing action of 5 the rolls produces superior results. The small amount necessary to, produce the desirable opaque character of the coatingl is found to have substantially no effect on t e properties of the blanket material and consequently rem sults in a blanket having all of the usual dcsirable properties of hectogra h blankets plus that of ready visibility of t e fresh im- A print on its surface.

order to better understand this invenfwgtion, reference is here made to the accom- 44i) backing sheet and ah panying drawing which discloses a hecto- 1 gr ph roll constructed in accordance with the present invention in Which--v Figure 1 is an enlarged cross sectional view 2o with the materials employed indicated on the drawing, and l ?j;

Figure 2 is a perspectivegview-of-aroll. As shown in the drawing, the'coatin ofthe described kind is applied ltogthe tlexib e l'iaffll-lV ing sheet in a mannerpdisclosed. :Jj It is to-be understoodffktliatithe above disclosure is merely given byway; of example as one form of the inventiort'and is' not` to be considered as limitingthe invention in'ny f The true scope of the` invention will be aS- certained from'an understandngof th-0peration of advantages of the present disclosure with the knowledge that itis one embodiment thereof. The scope of the invention is particularly pointed out in the appended claims. Y

I claim: A 1. A hectograph blanket, i comprising, a

on `one -face thereof of the usual g l: ycerine compol sition, said coatingc titanium'oxide.

2. A hectografliflanketcomprising, a

backing sheet an a eating on one face -thereof the usual glue and` glycerin com osition -said coating containing substantia yfl/Z of 1% of titanium oxide.

Signed at Chicago, Illinois, this 23rd day of J une,l 1928.

. WILLIAM HOSKINS, JR.

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