U.S. patent number RE29,832 [Application Number 05/810,440] was granted by the patent office on 1978-11-14 for printing mechanism.
This patent grant is currently assigned to Matsushita Electric Industrial Co., Ltd.. Invention is credited to Toshio Hayakawa.
United States Patent |
RE29,832 |
Hayakawa |
November 14, 1978 |
Printing mechanism
Abstract
A mangle wheel having first and second toothed portions arranged
in outer and inner arcuate paths forming a continuous loop is
rotatably mounted on a support which is pivotally mounted within a
housing. A gear is engaged with the continuous loop of teeth to
drive the mangle wheel in one direction at a low speed and in the
opposite direction at a high speed. A printer head unit is slidably
mounted on a guide shaft pivotally mounted on the side walls of the
housing. Rotation of the mangle wheel is transmitted to
longitudinal movement of the printer head unit to thereby move the
same in one direction to effect scanning and in the opposite
direction to quickly return the same to the original position. The
printer head unit is also movable transversely between an active
position in which the head unit is in contact with the plane of a
sheet of recording paper and an inactive position disengaged from
contact with the paper surface. The support is movable within a
limit of travel as the mangle wheel changes its direction of
rotation and arranged to move the printer head unit to the inactive
position during its return movement.
Inventors: |
Hayakawa; Toshio (Kadoma,
JP) |
Assignee: |
Matsushita Electric Industrial Co.,
Ltd. (JP)
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Family
ID: |
27582132 |
Appl.
No.: |
05/810,440 |
Filed: |
June 27, 1977 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
513068 |
Oct 8, 1974 |
03929215 |
Dec 30, 1975 |
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Foreign Application Priority Data
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Oct 12, 1973 [JP] |
|
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48-115241 |
Oct 12, 1973 [JP] |
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48-115242 |
Oct 12, 1973 [JP] |
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48-115243 |
Oct 12, 1973 [JP] |
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48-119322[U]JPX |
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Current U.S.
Class: |
400/320.1;
400/314; 400/320; 400/328 |
Current CPC
Class: |
B41J
19/20 (20130101); B41J 19/70 (20130101) |
Current International
Class: |
B41J
19/68 (20060101); B41J 19/70 (20060101); B41J
19/20 (20060101); B41J 003/04 () |
Field of
Search: |
;197/1R,16,18,55,82,84R,84B,49,90,89,114R,120 ;346/76R
;101/93.16,93.05 ;74/30 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Sewell; Paul T.
Attorney, Agent or Firm: Burns; Robert E. Lobato; Emmanuel
J. Adams; Bruce L.
Claims
What is claimed is:
1. A mechanism .[.for moving a writing unit of a nonimpact type
along a straight path to scan across each of a plurality of line
paths within a sheet of recording paper, comprising, a housing
having a bottom wall and a pair of opposing side walls, a support
rotatably mounted on said bottom wall, a mangle wheel rotatably
mounted on said support and having first and second toothed
portions arranged in an outer and an inner arcuate path to form a
continuous loop, a gear engaged with said loop of teeth, drive
means for driving said gear whereby said mangle wheel is rotated in
one direction at a first speed and in the opposite direction at a
second speed higher than said first speed, first guide means
arranged to guide said writing unit along said straight path, means
for connecting said writing unit with said mangle wheel to cause
said writing unit to move in opposite directions, second.].
.Iadd.according to claim 16, including additional .Iaddend.guide
means for guiding said recording paper .[., and.]. .Iadd.in a
direction normal to said straight path; and shifting .Iaddend.means
engageable with said support for .[.stepwisely.]. shifting said
paper .[.in a direction normal to the direction of movement of said
writing unit,.]. .Iadd.stepwise along said second guide means
.Iaddend.when said writing unit moves at said second speed.
2. The mechanism of claim .[.1.]. .Iadd.16.Iaddend., wherein said
.[.first.]. .Iadd.writing unit .Iaddend.guide means is movable
transverse to the direction of movement of said writing unit
between an active position in which said writing unit is in contact
with the surface of said paper and an inactive position disengaged
from contact with said paper surface and said support is engageable
with said .[.first.]. .Iadd.writing unit .Iaddend.guide means to
move said writing unit to said inactive position when said mangle
wheel changes direction of rotation.
3. The mechanism of claim .[.2.]. .Iadd.17.Iaddend., wherein said
.[.first.]. .Iadd.writing unit .Iaddend.guide .Iadd.means
.Iaddend.includes a shaft pivotally supported at .[.the.]. opposite
ends .Iadd.thereof .Iaddend.by said side walls.
4. The mechanism of claim .[.1.]. .Iadd.16.Iaddend., wherein the
center of rotation of said mangle wheel is located at a distance
from a pivot about which said support is rotatably mounted so that
said support is rotated about said pivot when the engagement of
said gear with said loop changes from said first toothed portion to
said second toothed portion.
5. The mechanism of claim 4, wherein said .[.first.]. .Iadd.writing
unit .Iaddend.guide means has an elongated guide frame, and wherein
said .[.rotatable.]. support .[.is provided with.]. .Iadd.has
.Iaddend.a first pulley rotatable in unison with said mangle wheel,
and second and third pulleys on said pivot, .[.and.]. said
elongated frame .[.is provided with.]. .Iadd.having
.Iaddend.fourth, fifth and sixth pulleys at one end thereof
adjacent said mangle wheel remote from said pivot and a seventh
pulley at the opposite end adjacent said pivot remote from said
mangle wheel, and .[.wherein.]. a length of wire .[.runs.].
.Iadd.running .Iaddend.from said first pulley, second pulley,
fourth pulley and seventh pulley .[.through.]. .Iadd.via
.Iaddend.said sixth pulley, fifth pulley to said third pulley and
finally to said first pulley, said third pulley being coaxially
rotatable with said second pulley and said fourth and fifth pulleys
being coaxially rotatable.
6. The mechanism of claim 4, wherein said pivot carries a pulley
.[.and.]., .Iadd.means being provided for transmitting
.Iaddend.said rotational movement of said mangle wheel .[.is
transmitted.]. via said pulley to said writing unit.
7. The mechanism of claim .[.1.]. .Iadd.16.Iaddend., wherein the
direction of movement of said support is substantially
perpendicular to the direction of movement of said writing
unit.
8. The mechanism of claim 1, wherein said shifting means comprises
first and second rollers rotatably mounted on said side walls in
contact with the circumferential periphery of one another, and a
ratchet wheel mounted for rotation with said first roller and
engageable with a ratchet pawl mounted on said support.
9. The mechanism of claim 7, .[.wherein.]. .Iadd.including
.Iaddend.a manual knob .[.is.]. coupled to said second roller for
rotation therewith, .[.and.]. said manual knob .[.includes.].
.Iadd.including .Iaddend.a one-way clutch means to prevent damage
occuring .[.on.]. .Iadd.to .Iaddend.said ratchet wheel when rotated
in a direction opposite to the direction of movement of said
paper.
10. The mechanism of claim 8, wherein .[.the.]. .Iadd.an
.Iaddend.intermediate portion of said second roller has a larger
diameter than .Iadd.have portions of the second roller .Iaddend. at
the opposite ends thereof.
11. The mechanism of claim 1, wherein said .[.second.].
.Iadd.additional .Iaddend.guide means includes a guide channel,
.Iadd.and .Iaddend.an elongated plate pivotally supported at
.[.the.]. opposite ends thereof within .[.the.]. .Iadd.a
.Iaddend.housing .[.and arranged to be in.]. .Iadd.for
.Iaddend.contact .Iadd.of the plate .Iaddend.with the .[.plane of
said.]. recording paper.
12. The mechanism of claim .[.1.]. .Iadd.16.Iaddend., including a
pulse generating mechanism which includes a second gear driven by
said drive means .Iadd.and similar to the gear engaged with said
loop, .Iaddend.a magnetic core one end of which .[.being.].
.Iadd.is .Iaddend.in proximity to one of the .Iadd.teeth toothed
portions .Iaddend.of .Iadd.the mangle wheel engaged by
.Iaddend.said .Iadd.second .Iaddend.gear; a coil wound on said
magnetic core, a permanent magnet adjacent said coil, and a
generally L-shaped member one end of which .[.being.]. .Iadd.is
.Iaddend.magnetically coupled to said permanent magnet and the
other end of which .[.being.]. .Iadd.is .Iaddend.in proximity to
another of said .[.teeth.]. .Iadd.toothed portions of the mangle
wheel engaged by said second gear .Iaddend.to thereby form a magnet
circuit, whereby a train of pulses are generated from said coil due
to variation of magnetic flux in said magnet circuit.
13. The mechanism of claim .[.1.]. .Iadd.16.Iaddend., including a
pair of switch contacts operable when said writing unit is in a
predetermined position to de-energize said drive means.
14. The mechanism of claim .[.10.]. .Iadd.13 .Iaddend.including a
cam rotatable in unison with said mangle wheel and a cam follower
resiliently supported .[.on said bottom wall.]. to operate said
switch contacts.
15. The mechanism of claim 5, wherein said writing unit is carried
on a support having a slot extending parallel with the direction of
movement of said writing unit and an eccentric cam having its
camming surface knurled and received in said slot, .[.and.]. an
extent of said wire between said sixth and seventh pulleys .[.is.].
.Iadd.being .Iaddend.engaged between the adjacent wall of said slot
and the knurled surface of said eccentric cam. .Iadd. 16. A writing
mechanism comprising; a writing unit of a non-impact type; means
for moving the writing unit along a straight path to scan across
each of a plurality of line paths within a sheet of recording
paper; a rotatably mounted support; a mangle wheel rotatably
mounted on said support and having first and second toothed
portions arranged in an outer and an inner arcuate path to form a
continuous loop; a gear engaged with said loop of teeth; drive
means for driving said gear whereby said mangle wheel is rotated in
one direction at a first speed and in the opposite direction at a
second speed higher than said first speed; writing unit guide means
for guiding said writing unit along said straight path; and means
connecting said writing unit with said mangle wheel to cause said
writing unit to move in opposite directions. 17. A mechanism for
moving a writing unit of a nonimpact type along a straight path to
scan across each of a plurality of line paths within a sheet of
recording paper, comprising; a housing having a bottom wall and a
pair of opposing side walls; a support rotatably mounted on said
bottom wall; a mangle wheel rotatably mounted on said support and
having first and second toothed portions arranged in an outer and
an inner arcuate path to form a continuous loop; a gear engaged
with said loop of teeth, drive means for driving said gear whereby
said mangle wheel is rotated in one direction at a first speed and
in the opposite direction at a second speed higher than said first
speed; writing unit guide means for guiding said writing unit along
said straight path; and means for connecting said writing unit with
said mangle wheel to cause said writing unit to move in opposite
directions.
Description
.Iadd.This is a reissue of U.S. Pat. No. 3,929,215, which patent
was based on applications filed on:
Oct. 12, 1973 Japan 48-115241
Oct. 12, 1973 Japan 48-115242
Oct. 12, 1973 Japan 48-115243
Oct. 12, 1973 Japan 48-119322[U]
Oct. 12, 1973 Japan 48-119324[U]
Oct. 12, 1973 Japan 48-119323[U]
Oct. 12, 1973 Japan 48-119325[U]
Oct. 12, 1973 Japan 48-119326[U]
Aug. 20, 1974 Japan 49-99926[U]
Aug. 20, 1974 Japan 49-99927[U]
The benefit of the priority of those applications is claimed
herein. .Iaddend.
The present invention relates generally to printing mechanisms for
use as a terminal equipment of a data processing machine, and more
particularly to a scanning mechanism in which a writing unit of the
nonimpact type is moved in opposite directions along a straight
path in proximity with or in contact with a writing surface.
The speed of recording data on paper in a data processing machine
is limited for one thing by the capability of the writing
mechanism, which in many cases is substantially less than that of
the data processing machine. Then, too, a substantial portion of
the costs of the data processing machine can be attributable
directly to the speed of the writing mechanism. Furthermore, the
mechanisms for these rapid writers are heavy, operate clumsily and
produce annoying noise.
One type of writing mechanism is, for example, the so-called impact
printer in which hammers print symbols on paper with the aid of
printing type or a type head.
A modification of this writing mechanism is the mosaic writer in
which pins and striking tools are used to record a symbol on paper
in the form of dots with the aid of a colored ribbon. An
arrangement is also known in which electrodes act on a special heat
sensitive paper. Another type of non-impact writing mechanism
utilize a stream of charged liquid droplets ejected by pressure
produced by electrical pulses.
One object of the invention is to provide a novel mechanism for
moving such non-impact type writing unit in opposite directions
along a straight path to sequentially scan across each of a
plurality of line paths within a sheet of recording paper.
Another object of the invention is to provide an improved scanning
mechanism which is simple in construction and compact in size.
A further object of the invention is to provide an improved
printing mechanism in which the writing unit is energized by
electrical pulses generated by a novel mechanism.
Still another object of the invention is to provide a novel quick
return mechanism in which a mangle wheel is provided with first and
second teeth arranged in an arcuate continuous path and a drive
gear engaged with the teeth to rotate the wheel in one direction at
a low speed and in the opposite direction at a high speed.
Briefly stated, an elongated support member is pivoted at one end
on the bottom wall of a housing. A mangle wheel having inwardly
facing teeth arranged in an arcuate path along its outer periphery
and outwardly facing teeth arranged inwardly of and in parallel
with the inwardly facing teeth forming a continuous loop is
pivotally mounted at the other end of the support. A drive gear is
engaged with the loop of teeth to rotate the mangle wheel in one
direction at a low scanning speed and in the opposite direction at
a high return speed. A writing unit of the non-impact type is
slidably mounted on a guide shaft which is pivoted at the opposite
ends to the side walls of the housing. A connection is provided
between the mangle wheel and the writing unit to transmit the
bidirectional rotation of the wheel to bidirectional linear
movement of the writing unit. The elongated support is swivelled as
the drive gear changes its engagement with the inwardly facing
teeth to the engagement with the outwardly facing teeth to rotate
the guide shaft about its axis. A sheet of recording paper is fed
into a guide mechanism. As the mangle wheel is rotated at a low
scanning speed, the writing unit moves along the guide shaft to
scan across the paper to produce visual image in accordance with an
output signal received, for example, from a data processing
machine. At the end of a line scan, the mangle wheel changes its
direction of rotation and moves the writing unit in the opposite
direction at a high speed to the original position. A pair of
switch contacts may be actuated in response to the movement of the
mangle wheel to stop rotation of the drive gear which may
subsequently be driven by signals provided by the data processing
machine. A pulse generator may be provided which comprises a gear
wheel of a magnetic material driven at a constant speed, a magnetic
core, a winding mounted on the core, a permanent magnet and an
L-shaped member of a magnetic material. The magnetic core has one
end disposed in proximity to one of the gear teeth with a
predetermined air gap and the L-shaped member has its short arm
portion coupled to magnet and its long arm portion directed to
another of the gear teeth so that a magnetic circuit is formed in a
loop including the gear wheel, the magnetic core and the L-shaped
member. As the gear wheel is rotated a train of electrical pulses
is generated across the terminal leads of the winding. When the
writing unit is a dot matrix type to record a symbol in the form of
dots, the electrical pulses are used to drive the writing unit in
timed relation with the output signal from the data processing
machine.
The invention will be described in detail in the following
description taken in connection with the accompanying drawings, in
which:
FIG. 1 is a plan view of a scanning mechanism of the invention;
FIG. 2 is a side view of the mechanism of FIG. 1;
FIG. 3 is a perspective view of a mangle wheel shown mounted on a
support;
FIG. 4 is a plan view of the mangle wheel and the support of FIG.
3;
FIG. 5 is a perspective exploded view of a paper guide mechanism of
the invention;
FIG. 6 is a cross-sectional view taken along line 6--6 of FIG. 5,
together with a writing unit located adjacent the front face of the
guide mechanism;
FIG. 7 is a perspective view showing an alternative arrangement of
the guide mechanism of FIG. 5;
FIG. 8 is a perspective view of a guide mechanism for two
directional slide movement of the writing unit showing relation
with the mangle wheel and its support;
FIG. 9 is an elevational view of the writing unit;
FIG. 10 is an end view of the writing unit;
FIG. 11 is a perspective view of an eccentric cam with a knurled
ring;
FIG. 12 is a side view of a pulse generator according to the
invention;
FIG. 13 is a view showing an alternative arrangement of rollers
arranged to guide and shift the recording paper;
FIG. 14A is a cross-sectional view of a manual knob for driving the
paper guide roller with a one-way clutch mechanism;
FIG. 14B is a cross-sectional view taken along line A--A of FIG.
14A;
FIGS. 15A to 15H are sequential views of a cam and cam follower
arrangement arranged to operate a reed switch with rotation of the
mangle wheel and
FIG. 16 is a schematic view showing various positions of the
writing unit in correspondence with the rotation of the cam of FIG.
15.
Reference is now made to FIGS. 1 and 2, a scanning mechanism of the
present invention is shown and comprises a housing 1 having a
bottom wall 2 and a pair of opposing side walls 3 and 3', a support
member 6 mounted on posts 4 and 4', and an electric motor 7 fixed
to a side plate of the support member 6 by screws 8. A spur gear 10
is mounted on the rotating shaft 9 of the motor 7. A gear 13 formed
of a magnetic material is mounted on the upper end of a shaft 12
rotatably supported by a bearing 11 mounted on the support member
6. A gear 14 is mounted on the lower end portion of the shaft 12
for rotation with the magnetic gear 13 and for engagement with the
gear 10 of the motor 7 and a gear 16 is integrally formed with the
gear 14 to engage a gear 20 mounted on the lower end of a shaft 18
rotatably supported on a bearing 17 mounted on the support 6. A
gear 21 is integrally formed with the gear 20. Rotation of the
motor 7 is therefore transmitted through the gear train to the
gears 14, 15 and gears 20, 21. A pulse generator 16 is mounted on
the support 6 by screw 33 and comprises a magnetic core 25 mounted
on a central bore 23 of a bobbin or spool 22 (see also FIG. 12) on
which is mounted a winding 24. The screw 33 is threaded through the
inner end of the core 25. The outer end of the core 25 is in
spacedly opposed relation with one of the teeth of the gear 13, the
air gap therebetween being adjustable by means of the screw 33. The
pulse generator 16 further comprises a magnetic plate 27, a
permanent magnet 28, an L-shaped magnetic member 29 and an elastic
member 30, all of which are mounted in side-by-side relation on the
screw 33 as a one-piece construction with the winding 24. The long
arm portion of the L-shaped member 29 extends parallel with the
longitudinal axis of the magnetic core 25 and the extreme end
thereof is disposed in spacedly opposed relation with one of the
teeth of the gear 13. A magnetic loop circuit is thus formed
through a path including the magnet 28, core 25, an air gap across
the core 25 and one of the teeth of gear 13, another air gap across
the extreme end of the L-shaped member 29 and another tooth of the
gear 13. Upon rotation of the gear 13, a train of electrical pulses
is generated in the winding 24 as the magnetic flux density is
fluctuated due to the variation of the air gaps. The electrical
pulses are utilized as a timing pulse as will be described later.
The elastic member 30 permits adjustment of the air gap between the
core end and the gear teeth while the screw holds the components
together. A swivel support 40 is rotatably mounted on a pivot 41
fixed to the bottom wall 2 (FIGS. 3 and 4). Pulleys 42 and 43 are
rotatably supported on the pivot 41. A pulley 49 and a quick return
mechanism or a mangle wheel 48 mounted on a pivot 47 rotatably
mounted on the swivel support 40 at a distance from pivot 41. The
mangle wheel 48 includes an inwardly formed or inner toothed
portion 50 on the outer peripheral edge and an outwardly formed or
outer toothed portion 51 on the outer wall of a peninsular 51a
which extends inwardly from the outer periphery. The inner and
outer toothed portions are at equal pitch and form a continuous
loop of teeth to mesh with the gear 21. The mangle wheel 48 is
further provided with a continuous arcuate guide groove 52.
The shaft 18 has the lower end thereof received in the guide groove
52 and the gear 21 mounted thereon is engaged with the inner or
outer teeth of the mangle wheel 48. When the shaft 18 is received
in the outer groove 52a, the gear 21 engages the inner toothed
portion 50 as illustrated in FIG. 4. The rotation of gear 21 causes
the mangle wheel 48 to rotate about the pivot 47 in a clockwise
direction at a low scanning speed. When the shaft 18 comes into
engagement with the inner guide groove 52b, the gear 21 engages the
outer toothed portion 51 and the wheel 48 is caused to rotate in a
counterclockwise direction position at a high speed. During the
transitory period, the support 40 swivels about pivot 41 to permit
the gear 41 to engage the outer teeth 51. Therefore, the gear 21 so
driven by motor 7 in the same direction of rotation causes the
mangle wheel 48 to rotate at a low speed in a clockwise direction
and at a high speed in a counterclockwise direction and causes
swivel movement of the support 40 during transition period. A
ratchet pawl 53 is pivotally mounted on the support 40 and biased
upwardly by a leaf spring 55.
A paper guide mechanism 59 is supported underside of the top wall
113 of the housing 1. The guide mechanism 59 comprises a support
frame 60 mounted at the opposite ends to the side walls 3,3', an
elongated guide plate 65 pivotally mounted within the support 60
and a lower guide member 68. The support frame 60 has a pair of
arcuate paper guides 61, an elongated groove 63 within which the
guide plate 65 is pivotally mounted by a pair of projections 64,
and lower and upper guide surfaces 62a and 62b. The guide plate 65
is provided with a pad 67 on the outer side thereof and a pair of
recesses 66 to engage the projections 64 to cause the guide member
65 to swing about the pivots or projections 64 within the groove 63
(see FIGS. 5 and 6). The lower guide member 68 has a pair of guide
members 69 to define a pair of arcuate guide channels with the
upper guides 61 to permit the forward edge of a sheet of recording
paper to be fed therethrough. A paper deflecting portion 70 is
provided on the inside of lower guide member 68 at a position
slightly lower than the lower edge of the guide member 65 so that
the forward end of the paper is deflected toward the guide member
65 into contact with the pad 67. Pivotal movement of the guide
plate 65 permits it to be brought in a full contact with the
surface of image producing elements or electrodes mounted on a
writing unit to be described later. The guide member 65 has its
lower edge preferably inwardly flared to aid in guiding the forward
edge of the paper to an upper position.
A roller 72 made of an elastic material is mounted on a shaft 71
rotatably supported on the side walls 3,3" and is in contact with
the circumferential periphery of a pinch roller 76 mounted on a
shaft 75 rotatably supported on the side walls 3,3'. A gear 73 is
mounted on the shaft 71 to engage a gear 77 mounted on the shaft
75. One end of the shaft 71 extends through the side wall 3' to
mount thereon a knob 74 to permit the user to manually transport
the paper to a desired position. A ratchet wheel 79 is mounted on
the shaft 75 and is engageable with the ratchet pawl 53 as the
swivel support 40 is rotated about the pivot 41 as referred to
above.
In order to provide resilient contact between the pinch roller 76
and the roller 72, the lower guide member 68 may preferably be
provided with a pair of roller supports 109 each having a recess to
rotatably support the shaft 75 instead of being supported on the
side walls 3,3' to urge the pinch roller 76 into abutment with the
circumferential periphery of the roller 72 (see FIG. 7).
A writing unit guide mechanism 80 is provided which comprises a
generally U-shaped support 81 and a pair of parallel guide shafts
82 and 83 fixedly supported thereby (FIG. 8). The opposite ends of
the shaft 82 extend through the side walls 3 and 3' to permit the
support 81 to swing about the shaft 82. The swingable support 81
has its intermediate portion resiliently connected to the housing
1. An extension arm 44 is provided on the swivel support 40. A
roller 46 is rotatably mounted on a pivot 45 mounted on the extreme
end of the extension arm 44 to engage the support 81. A carriage 35
is slidably supported on the shafts 82 and 83 and provided with a
projection 98, a bore 85, a guide slot 88 on the underside thereof,
a side slot 89, and a rotatable shaft 91 transversely received
therein and may be further provided with a permanent magnet 103
(FIG. 9). A cam 92 is eccentrically secured to one end of the shaft
91 and is provided with a knurled ring 93 to provide a firm
gripping of wires 94 threading through the slot 89 against the slot
wall (FIG. 10). A printer head unit 96 (FIG. 1) is provided, for
example, with a plurality of heat producing electrodes vertically
arranged in a row, and a recess 97 to be engaged with the
projection 98 of the carriage 35 and held in position by a leaf
spring 95. A pipe 86 is fixed to the support 87 through the bore
85. The shaft 82 of the guide mechanism 80 extends through the pipe
86 and the shaft 83 is received in the guide slot 88.
In FIG. 8, a pulley 49 is mounted on the shaft 47 for unitary
rotation with mangle wheel 48 and supports a loop of belt or wire
94 through pulleys 42 and 43 mounted on pivot 41. Pulleys 57 and 58
are rotatably mounted on pivot 56 mounted on the bottom wall 2.
Pulleys 100, 101 and 102 are rotatably mounted at one end of the
U-shaped support 81 and a pulley 99 is mounted at the other end of
the support. The wire 54 extends from pulley 49 to pulleys 43, 58,
101, 99, slot 89 of the head mounting 35, pulleys 100, 102, 56, and
returns to pulley 49. The mounting of pulleys 42 and 43 on pivot 41
about which the swivel support 40 is rotated ensures that the wire
is properly tensioned regardless of the movement of the support 40
without the need to provide a tension compensating means. A reed
switch 105 is mounted on an insulating support 104 attached to the
side wall 3. The reed switch 105 may have its contacts placed in a
circuit for de-energizing the motor 7 when the magnet 103 is
brought into proximity thereto. The motor 7 may be re-started for
subsequent scanning under the control of a signal delivered from a
data processing machine to which the present invention to related.
The carriage 35 is fixed to the wire 94 which extends between
pulleys 99 and 100 so that bidirectional rotation of mangle wheel
48 permits the writing unit 96 to move along the guide shafts 82
and 83.
In operation, the user inserts a sheet of heat-sensitive paper 111
through a slot 114 of top wall 113 into paper guide mechanism 59
and rotates the knob 74 counter-clockwise to feed the paper over
the guide surfaces 62a and 62b until the forward edge of the paper
slightly extends out of outlet 115. The motor 7 is energized to
cause rotation of the gear train comprising gears 14, 15, 20 and 21
at a constant speed. The rotation of gear 21 causes the mangle
wheel 48 to rotate in opposite directions at different speeds as
previously described. When the mangle wheel 48 is rotated in a
clockwise direction at a low speed as the gear 21 engages the inner
teeth 50, the writing unit 96 is moved from a starting position in
which the magnet 103 is in proximity to the reed switch 105 to the
opposite end of the guide shaft 82. While the writing unit 96 is
moved at a low speed, electrodes 112 mounted on the writing unit 96
are in contact with the frontal plane of the recording paper 111 by
spring 106 to record digital information thereon in a conventional
manner. As the writing unit 96 approaches the opposite end of the
guide shaft 82, gear 21 starts to disengage from the inner teeth 50
and to come into engagement with the outer teeth 51 to rotate the
mangle wheel 48 in a counterclockwise direction at a high speed so
that the printer head unit 96 is quickly returned to the starting
position. During the transsitional period, the swivel support 40 is
rotated about pivot 41 in a direction indicated by arrow L in FIG.
4 so that shaft 18 is transferred from engagement with the other
guide groove 52a to engagement with the inner guide groove 52b.
Upon swivel movement of the mangle wheel 48, the roller 46 is urged
into contact with the U-shaped guide 80 to rotate shaft 83 about
shaft 82 toward mangle wheel 48, so that writing unit 96 is moved
away from engagement with the plane of the recording paper 111.
Also, the swivel movement of the support 40 causes ratchet pawl 53
to engage ratchet wheel 79 to drive it a step further so that the
pinch roller 76 is rotated to shift the recording paper 111 by
engagement between the pinch roller 76 and roller 72 by the width
of a line scan. With the writing unit 96 being disengaged from
contact with the surface of the recording paper 111, the carriage
35 is quickly returned to the starting position for subsequent line
scanning.
A train of pulses generated by the timing pulse generator 16 may be
supplied to the electrodes 112 through an AND gate (not shown) to
which an output is applied from the data processing system to
record a symbol in the form of dots.
In order to feed the recording paper in a straight line path
exactly normal to the direction of line scan, the roller 72 may be
rounded as illustrated in FIG. 13 so that the paper 111 is
substantially in point contact with the paper surface. If the
roller 72 has a cylindrical surface, any slight difference in
diameter between the opposite ends of the roller 72 will cause the
paper to be moved in different speeds at the opposite edges.
In order for the knob 74 to be manually rotated counterclockwise to
feed the recording paper to a position in which line scanning
proceeds whether the ratchet pawl 53 is in engagement with the
ratchet wheel 79 or not, but to prevent the knob 74 from being
manually rotated clockwise when the ratchet pawl is engaged with
the ratchet wheel 79 so that damage may not occur to the ratchet
wheel 79, the knob 74 may preferably be provided with a one-way
clutch mechanism as illustrated in FIGS. 14A and 14B. The knob 74
may be provided with inner ratchet teeth 124 on the inner side
thereof and a ratchet pawl 121 is mounted on the shaft 71. The
rotation of knob 74 in a clockwise direction permits the pawl 121
to engage the ratchet teeth 120 to rotate the shaft 71 therewith
and the counterclockwise rotation of the knob prevents the pawl to
engage the teeth thereby preventing the unitary rotation of knob 74
and shaft 71 in a counterclockwise direction.
In order to effect switching of the reed switch 105, an alternative
arrangement is shown in FIG. 15. A cam 130 is mounted on the shaft
47 for unitary rotation with the mangle wheel 48, a cam follower
131 is pivotally mounted on a pivot 132 mounted on the bottom wall
2 and urged into abutment contact with cam 130 by spring 135
supported between the cam follower 131 and a post 134 mounted on
the bottom wall 2. A permanent magnet 133 is mounted on one end of
the cam follower 131. The reed switch 105 is disposed in proximity
to the magnet 133 to be operated thereby. The cam 130 is rotated in
unison with the mangle wheel 48 in opposite directions at different
speeds at previously described. In FIG. 16, the writing unit 96 is
shown driven at a high speed to return to the starting position and
as it approaches point A the cam 130 is in abutment with a lug 136
of the cam follower 131 and driven in a counterclockwise direction
at a high speed. As point B is reached in FIG. 16, the swivel
support 40 is started to rotate about pivot 41 as shown in FIG. 15B
with the cam 130 being substantially stopped rotation. At this
moment the quick return movement is completed and the mangle wheel
48 changes its direction of rotation. The swivel support 40 reaches
its limit of travel of movement as indicated by arrow L in FIG. 15C
in which the printing head unit 96 reaches point C as shown in FIG.
16 and magnet 133 is started to move away from reed switch 105 to
de-activate the same. The mangle wheel 48 is rotated at a low speed
to effect scanning and as point D is reached cam 130 is as shown in
FIG. 15D. This condition continues until point F is reached at
which the swivel support 40 is started to return to the original
position and cam 130 is substantially stopped rotation. As point G
is reached, support 40 is returned to the original position and cam
130 is started to rotate in a counterclockwise rotation at a high
speed for quick return to starting position. As point H is reached,
magnet 133 is again brought into proximity to the reed switch 105
to operate the switch contacts.
One of the advantages of the present invention is that a mangle
wheel rotatably supported on a swivel support permits the writing
unit to move in a straight longitudinal path at a low speed, to
return at a high speed and to move in a direction transverse to the
longitudinal path so as to disengage from contact with the paper
surface during its return movement and also permits the paper shift
mechanism to proceed the paper to a step further while the writing
unit is returned to the original position. This results in
compactness in overall size. A further advantage is that the
writing unit being returned to the original position free from
contact with the paper surface, the writing electrodes or writing
elements are ensured to have long usable life. The use of wire as a
means for transmitting movement of components permits them to be
arranged in a small area.
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