U.S. patent number 3,918,568 [Application Number 05/287,373] was granted by the patent office on 1975-11-11 for printing mechanism.
This patent grant is currently assigned to Kabushiki Kaisha Suwa Seikosha, Shinshu Seiki Kabushiki Kaisha. Invention is credited to Tadayoshi Shimodaira.
United States Patent |
3,918,568 |
Shimodaira |
November 11, 1975 |
PRINTING MECHANISM
Abstract
An improved printer including striking means positioned within
striking distance of a rotatable print drum, camming means for
oscillating the striking means in a swing arc less than the
striking distance between the print drum and striking means, and
regulating means for causing the striking means to strike the print
drum for printing contact therewith. The striking means is provided
with one axis of oscillation at a non-printing time and a second
axis of oscillation at printing time.
Inventors: |
Shimodaira; Tadayoshi
(Matsumoto, JA) |
Assignee: |
Kabushiki Kaisha Suwa Seikosha
(Tokyo, JA)
Shinshu Seiki Kabushiki Kaisha (Nagoya, JA)
|
Family
ID: |
13422123 |
Appl.
No.: |
05/287,373 |
Filed: |
September 8, 1972 |
Foreign Application Priority Data
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|
|
|
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Sep 10, 1971 [JA] |
|
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46-70112 |
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Current U.S.
Class: |
400/157.2;
101/93.48; 400/157.3; 101/93.3; 400/152; 400/166 |
Current CPC
Class: |
B41J
9/28 (20130101) |
Current International
Class: |
B41J
9/28 (20060101); B41J 9/00 (20060101); B41J
009/28 () |
Field of
Search: |
;101/93C,93R,94
;197/49,18,28 ;74/55,116 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bagwill; Robert E.
Assistant Examiner: Pieprz; William
Attorney, Agent or Firm: Blum, Moscovitz, Friedman &
Kaplan
Claims
I claim:
1. A printer comprising a rotatable print drum having an array of
print characters on the peripheral surface thereof, oscillatable
striking means for selectively striking said print drum for
carrying a printable material interposed therebetween into printing
contact with said peripheral surface of said print drum, said
striking means comprising a reciprocable print hammer having a
print face arranged opposite a predetermined portion of said print
drum and within striking distance thereof, a stopper guide groove
substantially opposite said print hammer face and extending
substantially laterally a predetermined distance toward said print
face, an interior cam slot substantially perpendicular to said
print face and stopper guide groove, and a tooth remote from said
print hammer depending downwardly from said striking means; a
stopper engageable in said stopper guide groove for limiting a
reciprocal return stroke of said print hammer after an imprint is
effected, said stopper being fixed relative to the reciprocable
movement of said print hammer; means for normally biasing said
print hammer against said stopper; a rotatable eccentric cam
mounted in said interior cam slot, said cam being unidirectionally
rotatable counter to the print stroke direction of said
reciprocable print hammer, said cam being arranged to oscillate
said striking means about said stopper in a nonprint position of
said printer; an impulse responsive trigger lever engageable with
said tooth of said striking means for driving said print hammer of
said striking means into printing contact with said print drum;
biasing means for normally biasing said trigger lever out of
engagement with said tooth of said striking means; and means for
generating an impulse to which said trigger lever is responsive for
driving said trigger lever oppositely of said normal bias thereon
for driving said print hammer; said striking means being
oscillatable about a point of contact between said trigger lever
and said tooth of said striking means in a print position of said
printer and said print hammer thereof being simultaneously
reciprocable between said print drum and said stopper.
Description
BACKGROUND OF THE INVENTION
This invention relates to an improved compact printing mechanism of
the type utilized in electronic desk calculators and other
numerical read out devices. More particularly, this invention
relates to a printer which generates little or no noise at printing
time.
Conventional printing mechanisms employ a high speed ratchet rotor
to impel a print hammer against a rotating print drum and the
impulsive engagement of the ratchet with the print hammer generates
a great deal of noise. Moreover, such printing mechanisms are
usually complex, insufficiently durable and difficult to
maintain.
Accordingly, the improved printing mechanism of this invention
includes a minimum number of interengaging and moving parts and is
substantially noiseless during the operation thereof.
SUMMARY OF THE INVENTION
Generally speaking, in accordance with the invention, a rotatable
print drum arranged for receiving an array of print characters on
the peripheral surface thereof is positioned within striking
distance of a striking means for selectively striking the print
drum and carrying a printable material interposed between the print
drum and striking means into printing contact with the peripheral
surface of the print drum. The striking means is provided with an
interiorly slotted mid portion defined by a continuous interior
edge thereof for receiving a camming means therein. Camming means
for oscillating the striking means in a swing arc less than the
striking distance between the peripheral surface of the print drum
is provided and the striking means engage at least a portion of the
continuous interior edge defining the interiorly slotted mid
portion of the striking means and regulating means are provided for
causing the striking means to strike and engage the peripheral
surface of the print drum for printing contact therewith for
selected periods of time.
When not in printing contact with the print drum, the striking
means is provided with a first axis of oscillation. Upon being
driven into printing contact with the print drum by the action of
the regulating means, the striking means is provided with a second
axis of oscillation. However, while in printing contact with the
print drum, the striking means undergoes little or no oscillation
whereby a clear, concise character is striken in the printable
material interposed between the striking means and print drum.
Therefore, a principal advantage of the improved printing mechanism
of this invention is the elimination of smudged printing during the
operation thereof. Additionally, the printable material, usually
paper, on which printing occurs is not ripped during the printing
process. Further, the noise which usually occurs during the
printing process is substantially reduced since this improved
printing mechanism does not utilize a high speed ratchet rotor as
an element thereof.
The invention accordingly comprises the features of construction,
combinations of elements, and arrangement of parts which will be
exemplified in the constructions hereinafter set forth, and the
scope of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the invention, reference is had to
the following description taken in connection with the accompanying
drawings, in which:
FIG. 1 is a semi-schematic representation of one type of printing
mechanism constructed in accordance with the invention; and
FIG. 2 is a semi-schematic representation of another striking means
embodiment which may be used in connection with the improved
printing mechanism of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, print drum 1 has an array of print
characters spaced apart on the peripheral surface thereof and is
mounted for rotation on a print drum shaft. Striking means 2
provided with a print hammer portion 5 thereof opposing print drum
1 and having an engaging tooth 4 at the opposite end thereof is
positioned adjacent print drum 1 for selectively striking print
drum 1 under the action of regulating means 8, hereinafter
described in detail.
Oval slot 3 is interiorly defined in the mid portion of striking
means 2 wherein camming means 7, preferably an eccentric cam, is
received and engages at least a portion of the continuous interior
edge defining interior slot 3 of striking means 2. Striking means 2
is further provided with guide groove 6 opposed to print hammer
portion 5 for receiving stopper 10 for limiting the oscillatory
movement of striking means 2 along a first axis of oscillation,
hereafter described. Striking means 2 is normally biased against
stopper 10 by the action of spring bias 11 thereon, one end of
spring bias 11 being connected to striking means 2 and the other
end thereof being connected to a fixed mounting. As striking means
2 strikes print drum 1, under the influence of regulating means 8,
ink ribbon 16 engages printable material 15, for instance, a paper
web, and both ink ribbon 16 and printable material 15 are
sandwiched between print hammer 5 and print drum 1 whereby a print
character is formed and inked on printable material 15.
Regulating means 8 includes a pair of lever arms, one arm
terminating in integrally formed pawl 9 arranged for engaging tooth
4 of striking means 2 for causing the print hammer portion 5 of
striking means 2 to strike and engage the peripheral surface of
print drum 1 for printing contact therewith. The other lever arm of
regulating means 8 is provided with an electro-conductive material
responsive to the electrical impulses generated by solenoid 13. The
trigger member or regulating means 8 including the lever arms and
pawl 9 is pivotably mounted on trigger shaft 14 proximate striking
means 2. Spring bias 12 connected at one end to a nub extension of
the trigger lever and at its other end to a fixed mounting normally
biases the trigger lever out of engagement with tooth 4 of striking
means 2 and against stopper 19. When solenoid 13 is activated an
electromagnetic field is provided thereby and the
electro-conductive lever arm of the trigger member is attracted
thereto whereby pawl 9 of the other lever arm of the trigger member
engages tooth 4 of striking means 2 urging it uppwardly and
outwardly thereby causing print hammer portion 5 to strike print
drum 1 and sandwich printable material 15 and ink ribbon 16
therebetween.
In an operational but non-printing interval, eccentric cam 7
continuously rotates in the direction of the arrow shown in FIG. 1
whereby tooth 4 of striking means 2 oscillates between phantom
positions 4' and 4", as shown in FIG. 1, while the innermost
defining edge of guide groove 6 constantly engages stopper 10 for
pivoting striking means 2 therearound and thereby providing a first
axis of oscillation for striking means 2 when in a non-printing
condition. When solenoid 13 is actuated thereby causing pawl 9 to
engage tooth 4 of striking means 2 causing print hammer 5 to strike
print drum 1, striking means 2 may undergo some slight oscillation
under the influence of eccentric cam 7 and the line of
inter-engagement between pawl 9 and tooth 4 become the axis of
oscillation therefor whereby striking means 2 is provided with a
second axis of oscillation which occurs during printing intervals
thereof. However, during a printing interval, substantially no
oscillation occurs because print drum 1 and eccentric cam 7 are
synchronized in movement and as eccentric cam 7 urges tooth 4
counter-clockwise pawl 9 continues to bias against tooth 4 to
maintain print hammer portion 5 in striking position against print
drum 1. The sequence of operation is such that printing terminates
as eccentric cam 7 urges tooth 4 into position 4" and tooth 4 is
simultaneously released by pawl 9 through the deactivation of
solenoid 13 whereby the trigger lever of regulating means 8
reassumes its normally biased position against stopper 19. For
instance, when print drum 1 rotates X times per minute eccentric
cam 7 rotates NX times per minute, and solenoid 13 will activate
pawl 9 for causing print hammer portion 5 to strike print drum 1 at
1/NX.
Referring now to FIG. 2, wherein an alternate striking means
embodiment 2' is shown, legs 17 and 18 of striking means 2' are
elastically deformable and securely engage eccentric cam 7 as it
rotates in slot 3. By providing striking means 2' with elastically
deformable legs which securely engage eccentric cam 7 even after
long periods of use a more uniform printing pressure of print
hammer portion 5 against print drum 1 is achieved during printing
intervals.
It will thus be seen that the advantages set forth above, among
those made apparent from the preceding description, are efficiently
attained and, since certain changes may be made in the above
constructions without departing from the spirit and scope of the
invention, it is intended that all matter contained in the above
description or shown in the accompanying drawings shall be
interpreted as illustrative and not in a limiting scope.
It is also to be understood that the following claims are intended
to cover all of the generic and specific features of the invention
herein described, and all statements of the scope of the invention
which, as a matter of language, might be said to fall
therebetween.
* * * * *