Improvements in Preparing Zinc Plates for Zincographic Printing Purposes.
Year: 1894

page_text: Date of Application, 10th Jan., 1894
Complete Specification Left, 9th Oct., 1894-Accepted, 24th Nov., 1894
PROVISIONAL SPECIFICATION.
Improvements in Preparing Zinc Plates for Zincographic Printing
Purposes.
I GUSTAV HENRY BLOCK of 20 Afghan Road Battersea S.W. in the County
of Surrey, Lithographer, do hereby declare the nature of this invention to be as
follows:-
This invention consists in a new process for rendering zinc plates of all kinds fit
for use for zincographic printing purposes without applying any coating.
This process is performed as follows: The zinc plate is first cleaned from grease
in the usual way (by means of pumice powder & water etc.). Subsequently the
plate is placed in a bath composed of 50 quarts of water, 1 quart of nitric acid,
3 lbs. of alum, in about the proportions mentioned in order to oxidise the surface
of the zinc plate. When the plate has been in the bath as described above for
about half a minute the plate is taken out of bath & rinsed with water so as to
remove the oxide which has formed, hereafter the zinc plate is placed again in the
above bath & is well rubbed over with a sponge or flannel to remove oxide which
may form till the plate ceases to form any more oxide. This operation gives the
plate the necessary grain which is required. Finally the plate is rubbed over
with carbonate of magnesia to neutralize any acid and remove any particle of
oxide which may adhere to the zinc plate. After rinsing with water and drying
the surface is ready for use.
Dated this Ninth day of January 1894.
Improvements in Preparing Zinc Plates for Zincographic Printing
Purposes.
I, GUSTAV HENRY BLOCK, formerly of 20, Afghan Road, Battersea, in the
County of London, but now of 18, De Grey Street, Hull, in the County of York,
Lithographer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :-
This invention relates to the preparation of zinc plates for printing purposes,
and consists in the novel treatment of the same as hereinafter described, whereby
the use of a coating upon the plate, which is now generally employed, is rendered
unnecessary.
In carrying out my invention I clean the zinc plate in any usual manner, for
instance, by rubbing it with pumice powder and water. The plate thus cleaned is
placed in a bath or solution composed of nitric acid, alum and water, in about the
following proportions, videlicet,

page_text: which time the bath should be shaken or kept in motion) it is taken out and rinsed
with clean water and rubbed with a sponge or flannel to remove the oxide which is
formed.
If any foreign matters, which have not been removed by the treatment last
described and which treatment has rendered them visible, the plate may be
sponged over with a solution of nitric acid and alum 50% stronger than that
described, and if after rinsing the plate the impurities still remain it is necessary
to planish or rub off such impurities which project above the surface of the plate
and would interfere with the subsequent use of the same.
The plate is now again placed in the bath and rubbed over with a sponge or
flannel to remove any oxide which forms thereon, until the plate ceases to form
any more oxide. This operation imparts or gives to the plate a grain such as is
necessary for a printing plate. The plate is finally rubbed over with carbonate of
magnesia to neutralize any acid which may remain thereon and to remove any
particle of oxide which may adhere in the grain.
The plate when rinsed with water and dried is then ready for use.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The preparation of zinc plates for printing purposes, consisting in first
cleaning the plate, then treating it in a bath or solution of nitric acid and alum in
the manner before described and then rubbing the plate with carbonate of magnesia
and finally rinsing and drying the same, substantially as described.
2. Zinc plates for printing nurnoses substantially as hereinhofora desnuibad
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
.
1. The preparation of zinc plates for printing purposes, consisting in first
cleaning the plate, then treating it in a bath or solution of nitric acid and alum in
the manner before described and then rubbing the plate with carbonate of magnesia
and finally rinsing and drying the same, substantially as described.
2. Zinc plates for printing purposes, substantially as hereinbefore described.
Dated the sh
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.