Improvements in Stencil Printing Machines.
Year: 1899

page_text: Date of Application, 20th July, 1899-Accepted, 7th Oct., 1899
COMPLEIN DIVIFICATION.
Improvements in Stencil Printing Machines.
I, BENJAMIN JOSEPII BARNARD MILLS, of 23, Southampton Buildings, in the
County of London, Patent Agent, do hereby declare the nature of this invention,
(a communication to me from A. B. Dick Company, of 154, Lake Street, Chicago,
Illinois, one of the United States of America) and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement: -
My invention relates to new and useful improvements in machines for print-
ing from stencil sheets, and particularly from mimeographic work, wherein the
stencil is formed in a wax-coated, fibrous sheet. The object of the invention is
to provide a cheap and efficient stencil printing machine, which will be capable
of being easily operated and which will turn out very perfect copies.
In order that the invention may be better understood, attention is directed
to the accompanying drawings, forming a part of this specification, and in which
Figure 1 is a plan view;
Figure 2, a side elevation;
Figure 3, a longitudinal section;
Figure 4, a transverse section;
Figure 5, a detail perspective view of the bearings for the oscillating stencil-
carrier, illustrating the mechanism for moving said bearings:
Figure 6, a detail section of the carriage, illustrating the mechanism for opera-
ting the paper gripping fingers and one of the latches for holding the impression-
roller out of engagement on the negative stroke, the carriage being in its outer-
most position with the paper gripping fingers open; and
Figure 7, a similar view showing the carriage in its innermost position with
the paper gripping fingers closed.
In all of the above views, corresponding parts are represented by the same
numerals of reference.
Each
1 is a rectangular bed to which the side-frames 2, 2, are secured. The side-
frames 2, 2, are formed with tracks 3, and working on said tracks is a frame 4,
the side members of which are provided with racks 5, 5. The sheets to be
printed are carried on a table 6, having preferably a hinged extension 7, which
can be turned over to shorten the length of the machine when not in use.
of the side-frames 2 is provided with a cast extension 8 formed with a slotted
bearing 9 on its top. Mounted in each of these bearings is a bearing-box 10
for the spindle 11 of a toothed disk 12, two of these disks being used. Connect-
ing the toothed disks 12 is a perforated, metallic sheet 13, which, together with
the said disks, constitutes an oscillating stencil-carrier. In order to oscillate
this stencil carrier, I provide the spindle 11 of one of the disks 12 with a gear 14,
with which meshes a pinion 15 operated from a crank 16. The shaft of the
pinion is provided with a serrated disk 17 and the crank 16 is provided with a
corresponding disk 18, a thumb-screw 19 being employed to hold the said ser-
rated disks in engagement. By loosening the screw 19, it will be observed that
the handle 16 may be adjusted to any position with respect to the oscillating

page_text: stencil-carrier. Carried upon the perforated plate 13 is a sheet or pad 20 of
suitable textile material. One end of this sheet is stitched over upon a bar or
rod to secure the sheet, and the other end of said sheet is passed through a longi-
tudinally slotted shaft 21, extending beyond one of the disks 12 and formed
with a rectangular head 22 for the reception of a key. A spring-pressed pawl 23
is employed to lock the shaft 21 normally in any position to which it may be
turned. By turning the shaft 21 with a suitable key, the sheet or
pad 20 can be
stretched very tightly upon the perforated sheet 13. The stencil sheet is placed
in position over the pad 20 and held in any suitable way, as, for instance, by
the ordinary clips 24.
The toothed disks 12 engage the rack portions 5 of the side pieces of the
frame 4, whereby the oscillating movement, first in one direction and then in
the other, of the disks 12 will provide for a reciprocation of the frame 4, and by
properly proportioning the disks 12 the movement of the frame 4 will correspond
exactly with the surface velocity of the stencil. In order to hold the toothed
disks 12 normally in engagement with the racks 5 of the paper-carrying frame 4,
I employ links 25 and 26, which engage with the pins 27 formed on the bearing-
blocks 10. The link 25 connects with a finger-lever 28, which is carried upon a
rock-shaft 29 having a crank 30 at its opposite end to which the link 26 is con-.
nected. By elevating the lever 28, the links 25 and 26 will elevate the bearing-
blocks 10 so as to disengage the toothed disks 12 from the racks 5. The stencil-
carrying frame may now be moved to bring the stencil to any desired position
of adjustment relative to the paper-carrying frame, when the parts will be again
engaged by depressing the finger-lever 28. The lever 28 is normally locked in
its lower position to maintain the engagement of these parts by a pin 31 engag
ing an opening in one of the side-frames. By removing the upper ends of the
links 25 and 26 entirely from the pins 27, the oscillating stencil-carrier as a
whole may be removed for any purpose.
Pivoted to each of the side-frames 2. is a bell-crank 32, and mounted in these
bell-cranks is an impression-roller 33, made preferably principally of rubber.
The spindle 34 of the impression-roller is carried at its ends in open bearings
in the bell-cranks 32, whereby the impression-roller may be removed for any
purpose. Each of the bell-cranks 32 is operated by a spiral spring 35, by which
the impression-roller will be elastically impelled upward into contact with the
stencil or the sheet in engagement therewith when an impression is desired.
The springs 35 are adjusted by the adjusting screws 36 of ordinary construction.
In order to move the impression-roller 35 out of engagement with the stencil,
I employ an eccentric 37, engaging with each of the bell-cranks, as shown, said
eccentrics being carried on a rock-shaft 38, to the outer end of which is keyed
a finger-lever 39. By operating the finger-lever, the rock-shaft will be turned,
engaging the eccentrics with the vertical arms of the two bell-cranks and moving
the impression-roller positively downwards. The impression-roller 33 is provided
at each end on its spindle 34 with an anti-friction roller 40, with which the under
surfaces of the sides of the frame 4 normally engage. At each end of the stroke
of the frame 4, a cam 41 or 42 engages each of the anti-friction rollers 40 to move
the impression-roller downwards out of engagement with the stencil sheet or with
the sheet being printed. Co-operating with the horizontal arm of each of the
bell-cranks 32 is a latch 43, having a shoulder 44 thereon, with which a pin 45
carried on each of the cams 41 is adapted to engage, whereby when the cams 4.1
have engaged the anti-friction rollers 40 to depress the impression-roller the
pins 45 will engage the lugs 44 of the slides 43 to move the latter over the hori-
zontal arm of each of the bell-cranks 32 to lock the latter in their depressed posi-
tion. Each of the cams 42 is provided with a pin 46 adapted to engage the lug 44
of the corresponding lock 43 when the frame 4 rears the completion of its negative
stroke, i.c., the stroke upon which a printing operation does not take place. By
the arrangement of cams which I have described, the frame 4 when it approaches
the end of its positive stroke causes the cams 41 to depress the impression-roller

page_text: and after such impression-roller has been depressed the pins 40 on the cams 41
will engage the latches 43 to hold the impression-roller locked downwards.
During the entire negative stroke therefore, the impression-roller will remain
locked in its depressed position. Near the completion of the negative stroke,
the cams 42 engage the anti-friction rollers 40, so as to depress the impression-
roller to a very slight further extent, and the pins 46 engage the latches 43 to
release them from the bell-cranks 32. Upon the starting of the positive stroke,
the cams 42 will allow the impression-roller to be forced upwards into contact
with the sheet being printed by the tension of the springs 25. In this way it
will be observed that the impression-roller is maintained in an inactive condi-
tion during the entire negative stroke, and is allowed to be impelled upwards
always at the same instant in the travel of the paper-carrying frame 4 during its
positive stroke.
By suitably adjusting the position of the stencil relative to the reciprocating
frame 4 as I have described, it becomes possible to secure the printing of stencil
matter within very close limits of adjustment. Where finer adjustment is neces-
sary, I provide the regulation of the length of the limiting fingers which deter-
mine the position of the sheet as fed by the operator. These fingers preferably
comprise a forklike head, the outer times, 47, of which bear upon the surface
of the table 6 around an opening 48, and the central line 49 being provided
with a downturned finger, as shown, which forms an adjusting stop to the sheet.
The shank 50 passes through a rock-shaft 51, as shown, and a spring 52 main-
tains the fingers in their outermost position, a very fine adjustment being per-
mitted by the adjusting screw 53. By regulating the distance of the limiting
fingers 49 with respect to the shaft 51, an accurate adjustment of the sheet will
be permitted. In order to regulate the position of the sheets sidewise, I employ
the usual gauge 54, the position of which is regulable by an adjusting screw 50
working in a slot, as is common. When the sheet of paper to be printed has been
moved by the operator into engagement with the fingers 49 and the gauge 54,
and the frame 4 returns on its negative stroke to grasp the paper and draw it
through the machine between the stencil and the impression-roller, it is neces-
sary to elevate the fingers 49 from the sheet to permit this to be done, and to
accomplish this result I employ an arm 56, which is carried on the rock-shaft 51
and which engages a cam 57 formed integrally with the cam 42, as shown. A
rearwardly extending arm 58 prevents overthrow of the rock-shaft 51.
The grippers for engaging the sheets and drawing them through the machine
are carried on the frame 4. Each comprises preferably a stationary top mem-
ber 60, having the two prongs 61, 61, and the bottom member 62 pivoted thereto.
The members 62 are normally pressed upwards into engagement with the
prongs 61 by a leap-spring 63, as shown. In order to separate the grippers, I
extend the movable member 62 backwards, as shown, and engage it in a cut-
away portion of a rock-shaft 64, which, when partially turned, will obviously
elevate the rear ends of the members 62 to separate their forward extremities.
This rock-shaft 64 carries an arm 65 at one of its extremities, which arm is
adapted to be moved in one direction or the other by the engagement with it of
pins 66 and 67 carried on a slide 68, which extends parallel to one of the side
members of the frame 4. The slide 68 carries a pin 69 adapted to engage the
lower end of a lever 70, which is normally held in engagement with a stop-
pin 71 by a spring 72. The pin 67 is extended through the slide 68 and is adapted
to engage a lug 73 on the side-frame 2, almost at the very end of the completion
of the negative stroke, whereby at that moment the paper-carrying frame 4 will
be moved relatively to the slide 68, causing the rock-shaft 64 to be partially rota-
ted and allowing the fingers 61 and 62 to grip the sheet through the pressure of
the spring 63. The movement of the paper-carrying frame 4 is limited both at
the end of its positive and negative strokes by the engagement of pins 74 with
an elastic stop or buffer 75 carried on each of the side-frames 2.
The operation will be as follows:-The stencil sheet or of her stencil is secured

page_text: by the clips 24, or in any suitable way, smcothly and evenly upon the cloth sheet
or pad 20 around the oscillating stencil-carrier. A suitable, relatively thin ink
is now applied to the interior of the perforated sheet 13 by means of a brush or
sponge, to form a comparatively thin film or coating. This ink exudes through
the pad or sheet 20 and passes through the perforations in the stencil. As it is.
consumed in the making of the copies, I find that the atmospheric pressure to
which it is subjected will maintain a very uniform and effective supply of ink at
all times in the stencil sheet. As the ink becomes exhausted, it is a matter of
only a few seconds to apply a fresh coating. I find in practice that a compara-
tively thin film of suitable ink, applied with a brush, will enable several hundred
copies of mimeograph matter to be secured without renewals.
Having placed the stencil in position upon the stencil-carrier, it next becomes
necessary to adjust the position of the stencil relative to the sheets to be printed,
in order that the matter may be properly displayed upon the copies. This is
an operation which depends largely upon practical experience, and the proper
alignment of the copy is effected, as before stated, by operating the lever 28 to
elevate the stencil and to disengage the toothed disks 12 from the racks 5, thus
permitting the stencil to be turned to any position that may be desired, without
effecting the movement of the frame 4 which carries the paper.
The proper
alignment can be very conveniently made by experimenting with one or two
copies, and by changing the relative position of the oscillating stencil-carrier to
the paper-carrying frame. The parts being in correct alignment, a number of
sheets of paper are placed upon the bed 6 and are advanced one at a time by the
operator until they come into contact with the fingers 49. The handle 16 is
moved by the operator first in one direction and then in the other, the engage-
ment of the pins 74 with the elastic buffers 75 acting effectively as limiting stops
to these movements. Upon the negative stroke of the machine, assuming a sheet
of paper to be in engagement with the fingers 49, the rotating of the handle 16
will move the racks 5 and frame 4 rearwardly until the arm 56 of the rock-
shaft 51 engages the cam 57, at which time the fingers 49 will be elevated from
the sheet. At about this time, however, the grippers 61 and 62 will be opened
and will enter the notches 48 of the bed 6, so as to engage over the sheet, while
at the completion of the negative stroke the engagement of the pin 67 with the
stop 73 will rotate the rock-shaft 64 to permit the springs 63 to operate the
grippers 61, 62, to close upon the sheet and to draw it by the movement of the
frame 4 beneath the stencil. In this movement, the sheet will be engaged by
the stencil and will. be held up in contact with the stencil by the impression-
roller. At the completion of the positive stroke, however, after the
printing has been effected, the pin 69 the slide 68 engages the
lever 70 and the slide is moved in the reverse direction to
separate the grippers 61 and 62 and permit the sheet to fall flatwise in a
suitable receiving box placed at one sile of the machine. During the negative
stroke of the machine, it is, of course, necessary that the impression-roller should
be withdrawn from the stencil, in order that it may not become smeared with
ink, and also to permit the grippers 61 and 62 to pass between the impression-
roller and the stencil to grasp the new sheet. This movement of the impression-
roller is effected, as explained, by the cams 41 and 42, the former depressing
the impression-roller, which will be locked by the latches 43, while the latter
cams 42 depress the impression-roller and subsequently withdraw the latches,
so that upon the positive stroke the impression-roller may be again moved up-
wards by the springs 35, to force the sheet against the stencil and effect the
printing operation.
on
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. A machine for making copies from flexible stencils, characterized by the

page_text: employment of an oscillating stencil-carrier and a frame which reciprocates back
and forth adjacent to the carrier, the frame and carrier being geared or otherwise
connected together, whereby sheets of paper may be engaged by grippers con-
nected to the frame and drawn between the stencil and an impression-roller.
2. A stencil printing machine of the type described in Claim 1 and further
characterized by the employment of mechanism for operating the impression-
roller to force the sheet against the stencil as the frame is moved away from the
stencil-carrier but to move the impression-roller away from the stencil upon the
return movement of the frame.
3. A stencil printing machine such as is described in Claim 1 and further
characterized by the employment of gripping fingers which engage the sheets
to be printed one at a time and draw them between the stencil and the impres-
sion-roller and which release the sheets to allow them to be deposited in a recep-
tacle after the printing has been effected.
4. A stencil printing machine such as is described in Claims 1 and 3 and
further characterized by the employment of limiting stops against which the
sheets to be printed are preliminarily adjusted but which are elevated out of the
way of the sheets as the gripping fingers engage the sheets to draw them into
engagement with the stencil.
5. In a stencil printing machine, the employment of an oscillating stencil-
carrier having a perforated foundation over which a sheet of fabric is placed, one
edge of said fabric being wound around an adjusting roller, by which the fabric
may be placed under the desired tension.
Dated this on day 01 July 19.
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.