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Патент USA US2404689

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Jy 23, 1946.
Filed Jan. 15, 1945
Patented July 23, 1946
2,404,689 l
"z_.smr Es rar-sur orricsf
rI_faftville; Conn., assigners to The Aspiriook Cor
poration, Jewett City, Conn., `a‘ corporation' of
V Delaware
` Applicaticn January 16, 1945,-seria1’No. 572,998A
l Claim. (C1. lOl-#153)
u i
The‘present invention relates to Ydoctor blades
for use in textile printing machines and similar
usesyf" More particularly, l it relatesto a -doctor
blade that is protected from corrosion from the
width from two to three inches, in thickness from
à to als’ of aninch, and in length according Ato
the length of the engraved roller, beingusually
action 'of the constituentscflt'he printing pastes
edge, i. e., the edge- that contacts the‘rollentis
used'inj such printing, and which may be sharp
some two inches longer. Their top or working
' filed to a suitable bevel and then sharpened by
en‘edwhen such doctor becomes corroded without
hand with anoil stone> to a Vrazor-like keenness.
Their bottom edges `are ñrmly clamped between
undue wear from the sharpening operation. ,
In printing textile fabrics, a copper roller that
two brass holdersor one ofbrassand `one of4 iron,
is engraved with the’d'esign `,to be printed rotates 10 tightlyscrewed together and furnished at` each
against apress cylinder’and prints the design
end with a supporting pivot that rests on a _brack
upon a' cloth passing over the cylinder. _The color
et attached to the bearingrof the rollen anda D110-,
paste'is‘supplied by `a `furnisher roll _that rotates
jecting lever by means of >weights or screws serves
againstfthe " engraved copper roller. |I‘he fur
topress the blade on the roller.
-. .
nisherroll rotates‘în` afont containing the'print 15 In` order to prevent the unequal wearing of
ing pasteand,v as it contacts the engraved roll,
their sharp edges, which would occur if they >were
deposits the color thereon. The engraved roll,
allowed'to rest continuously in one position on
however, when it rotates against the cloth to’ be
the roller, the doctor blades are given a fslight :to
printed, should have this color paste only in the
and iro movement in a direction parallel to the
depressions of the engraving,"b`ut the‘furnisher 20 axis of the roller. Notwithstanding all thesepre
roll deposits color not only in the'engraving but
cautions, however, the edge ofthe doctor blade
also wherever it contacts the engraved roll,` both
in a comparativelyI short time becomes uneven
within andwithout the engraved design through
dueto corrosionr and when this happens, streaks
out its'lenfgth.“ Accordingly, a sharp doctor blade
oit color` pass under the doctor and cause smears
is provided to `‘clean the engraved roll, that is, to a up‘oriìthe -cloth that is being printed. They‘then
scrape off all the paste deposited thereon except
must be removed and resharpened. '
where it is contained in the intaglio design.
Here, again, frequent sharpening of the doctors
This doctor blade is a razor sharp steel blade
causes a Wearing down and ñnally a Wearing out
which is kept pressed against the engraved roll
of the blades. In sharpening, the printer not
only goes over the bevelled face of the doctor with
a file and stone, but he also must “face” it, that
is, he must file and stone the bearing face that
rests on the roller. This “facing” or filing of
the bearing face wears down the original thick
and which scrapes the excess paste therefrom so
that it ilows back into the font.
In general, textile fabrics are printed with vat
colors, commercial colors (basics and alizarine)
or aniline blacks. In printing with vat colors,
the paste is alkaline whereas with commercial or
aniline colors, the paste is on the acid side. 'I'hese
ness of the blade and, after a certain amount of
such wear is reached, the doctor blade must be
pastes are very corrosive and especially so the an
discarded as it no longer will fulñll its purpose.
ilines, so that the edge of the doctor blade be
comes eroded and uneven and unsuitable for per
forming its function.
`The sharpening or “getting up” of the edge
of the doctor blade is one of the most difficult
and most important parts of the machine print
As a result of this the doctor blade must be
er’s work. The quality of this edge depends not
removed from the machine and refiled to sharpen
only upon the weight and scale of the engraving
its edge some times several times during a day’s
also upon the thickness and hardness of the
operation. This causes considerable loss of time
in printing. Moreover, no matter what kind of 45 doctor blade, the angle at which' it rests upon
the roller, the pressure applied to it, and upon
paste is used, the moisture in the paste and in the
the viscosity and density of the printing
air will have a corrosive action on the doctor
color which it has to clean oiî. Generally speak
blade, and it is common practice to remove all
ing, the edge of the Well sharpened cleaning doc
doctor blades at night and, before setting up the
be ñled to a razor sharp edge and replaced, an
tor is perfectly straight, absolutely smooth
throughout its entire length, and bevelled to a
operation that takes ordinarily an hour or two, all
depending upon the number of rollers used.
These doctor blades are made of the best qual
rather obtuse angle. It is sharp as a razor and
any roughness, unevenness or the slightest break
in the edge is suñicient to allow color to escape
machines in the morning, all doctors must again
ity of medium tempered steel.
They vary in 55 under it with the result that the ñnished print
exhibits serious defects in the form of streaks or
cloudy patches of color.
It is an object of the present invention to pro
vide a doctor blade _which will be protected
against corrosion to the greatest possible degree.
and which, nevertheless, can be maintained at the
required razor sharpness of the present doctor
doctor will not be worn thin under the sharpening
In the drawing, Fig. I represents schematically
the arrangement of the rolls on a textile printing
machine with the doctor blade in place; Fig. II
_shows a doctor blade ofthe invention indetail.
" KReferring to Fig. I, is the cylinder around
which the blanket 2 is iap'p'ed. The cloth 3 which .
It isa further object of the invention -to provide
is being printed passes between the blanket 2 and
a doctor blade that will not wear -down readily
" the engraved roll 4. The furnisher roll 5 rotates
under the sharpening operation and that as a; jin Vthefont 6 andcontacts the engraved roll 4
consequence retains its thickness and hence its
eiliciency over a very long period of time.
By use of the doctor bladesof'the present in
vention, frequent resharpening is unnecessaryV and
furthermore the doctor blade may be left in place
on thev printing machine all night andthe Work
which rotates in reverse direction to the rotation
of furnisher roll 5. 'I'he doctor blade 'I' presses
with' its plated ‘face I 0 bearing against the en->
graved rollfd, thus scraping the color from said
roll except where it fills the depressions of the
of printing can be resumed immediately in the
In Fig. II is shown the doctor blade With its
morning. This results in a saving of many hours
holder or sheath 8, its steel body 9 and chromium
a day in printing operations and a substantially 20 or tantalum plating l0 on one side of the steel
greater output of workïfrom each machine.
'- ~Brieily`"described, the invention consists of pro
>It will be apparent that when a doctor of the
viding ay doctor blade having an edge bevelled in
present invention is sharpened by the printer,l
theusual manner to an obtuse angle and sharp
only the bevelled side of the blade Will be filed and.AV Y
enve‘d'toa razor edge and having the face of the 25 stoned, as neither the ñle nor the stone will make
blade, that is, that side of the blade that rests on
the roller', plated With a hard, smooth, corrosion
resisting metal such as chromium or tantalum.
Theplatingis carried to the razor edge of the
any impression on the hard, smooth chromium
or tantalum coating on the bearing Aface. Asa
result; there will be little wear on the plated’face
and thersurface on that side will always remain
doctor blade on the bearing side so that the cor 30 the same without loss of thickness of the blade.
rosive acids in the printing paste do not alïect the
Such a plated doctor blade will have a life several
steel edge of the blade. On the other hand, if
times as long as the ordinary doctor blades> now
afterl use, some small amount of corrosion ofthe
in use and in addition Will retain >its sharpness
edge of the doctor'does take place, the master
much longer, thus requiring fewer sharpenings.
printer may remove it and V-resharpeh it in the 35
Having thus described -our invention,> what wel
usual‘manner’sin'ce' the bevelled face of the'blade
is not'ïplated.> The-plated side> of the blade, how
ever,'wil1 not wear under this sharpening, as the
platingefgives a very hard and smooth surface on
which the file and stone will glide Without biting
into .the metal. Thecoatings used forV this pur
pose should be metals that are not only resistant
to. thepactionjof acids. but should have a very.
hard-„smoothsurface so that the bearing face
cannotbe ñled vor stoned. When so coated, the
A doctor blade comprising a steel backing
beveled down to a razor sharp edge and a plating. .
of chromium on the unbeveled underside extend
ing to the edge, the plated side of said edge being
a adapted andarranged to bear on a
of aÍtextile- printing machine.
printing roller.
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