Note: Descriptions are shown in the official language in which they were submitted.
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PRINTING TYPE ORIENTING DEVICE FOR LABEL PRINTING MACHINE
sackground of the Invention
Field of the Invention
This invention relates to a means for maintaining the
orientation of the type faces of a printing device for a
portable label printing and dispensing machine (hereinafter
referred to as "label printing machine") and more particularly,
for maintaining the type faces always parallel to the surface of
a label to be printed, so that highly precise printing without
any fluctuation in the depth of the printed figures can be
attained.
Description of the Prior Art
There are generally two ways to attach a printing
device to a label printing machine. In one method, the printing
device is attached to yoke arms which are disposed at the front
portion of a hand lever and the printing deviae is swung ~p
and down by the operation of the hand lever. When the printing
device is moved down by squeezing of the hand lever to the hand
grip, the type faces on the underside of the printing device are
brought into contact with the label that is then on a fixed
platen. In the other method, the printing device is directly
fixed to the label printing frame. Since the printing device is
stationary, the platen that supports a label thereon is moved up
by the squeezing of the hand lever to the hand yrip so as to
bring the label into contact with the type faces that are
disposed on the underside of the fixed printing device.
A printing device with which the present invention is
used comprises a plurality O r endless stamp belts that are
stretched between rotatable selector wheels and positioning
gears and that are arrayed side by side. The desired type on
each stamp belt is shifted to the printing position by
manipulating a selector knob which rotates the respective
selector wheel. The positioning gears are supported by spring
actuated supporting members, which maintain the types on the
stamp belts parallel to the surface of a label to be printed.
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The spring actuated supporting members all include a
single bridging member that is secured to the frames of the
printing device. Each spring actuated supporting member also
comprises a plurality of pins, compression springs and pushing
members which are urged down by the compression spring toward
the positioning gears. This conventional structure will be
further described with reference to the accompanying drawings.
Because the undersurfaces of the pushing members
always press against the outer surfaces of the positioning gears
under the force of compression springs, the positions of the
gears and of the type faces on the stamp belt are set to the
printing position and are held at a predetermined angular
orientation with respect to the label being printed.
Each pushing member is moved vertically along its pin
as its positioning gear is rotated. Therefore, the pushing
members are liable to become loose and may rock owing to the
wearing of the engaging surfaces of the pin and pushing members.
Accordingly, the type faces cannot be maintained parallel to the
surfaces of the labels to be printed. Labels printed by type
faces that are not parallel to the label causes the depth of the
printed figures to be uneven, and the printed figures are
difficult to be read.
In the past, figures that were not printed clearly
have still been accepted because they have only had to be
readable with the naked eye when customers buy commodities and
cashiers add up the sales.
In recent years, what is called the P.O.S. (point of
sales) system has become widely employed. Machine readable bar
codes or optically readable characters which are printed on
labels are read out by optical character reading machines that
are connected to electronic computers, and sales data and
management data such as stock, proceeds, customers relative to
commodities and gains are processed and stored by the computers.
For optical character readers, it is necessary to print labels
more clearly and precisely as compared with characters that are
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to be read wlth the naked eye.
Summary of the Invention
The present invention seeks to provide an improved
printing device for a label printing machine, in which the type
faces on stamp belts can be held parallel with the surface of a
label to be printed.
The present invention further seeks to provide a
printing device, which enables clear and precise printing, which
can be used for a long period of time without deterioration of
its performance, which is not complicated in structure and which
can be produced easily at low cost.
The printing device is comprised of a plurality of
spring actuated supporting mernbers. There is a bridging member
serving all of the supporting members and that is disposed in
the space between the stationary frames that are on and that
define both sides of the printing device. There are a
plurality of pins, the top portions of which are fixed to the
bridging member. There are pushing members which ea~h have a
sliding recess to receive therein the bridging member. A
sliding hole is formed in the bottom surface of each sliding
recess. The pushing members have an undersurface which is
brought into contact with the top of the positioning gear. A
compression spring is disposed around each pin and spans the
space between the bridging member and the bottom surface of the
sliding recess for always pressing the pushing member into
contact with the positioning gear and for depressing that gear.
The pushing members in the present invention are
taller than those in the prior art device, and the pushing
member is vertically supported by both the spring actuated pin
and the side walls of the bridging member. Therefore, the
pushing member is always moved vertically without any play and
the undersurface of the positioning gear together with the type
faces on the undersurface of the pushing member can always be
maintained horizontal and parallel to the label surface.
Thus broadly the present invention comprehends a
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device for orienting the type faces on a stamp belt of a
printing device, which is used for a label printing machine, or
the like. The printing device comprises a plurality of stamp
belts, each having an exterior and each carrying a plurality of
types along its exterior. The printing device further comprises
a respective selector wheel for each of the belts and around
which each of the belts passes and which each of the belts
engage. A respective positioning gear for each belt, and around
which each belt passes, engages each belt. The positioning gear
is multisided, includinq a first side enqaqeable with a
positioning member and out of engagement with the belt. A
second side points in a printing direction and in engagement
with the belt, such that a type at the positioning gear second
side will be printed. The stamp belt is drawn securely around
the positioning gear, thereby acting in opposition to an elastic
means. The printing device also comprises a bridging member
supported stationary with respect to the printing device. The
bridging member has two oppositely facing, upstanding sides,
each extending generally parallel to the axis of rotation of the
positioning gear. The bridging member has a bottom side. The
type face orienting device comprises the bridging member and a
respective pin for each belt. Each pin is secured to and
immovable with respect to the bridging member and each pin
projects below the bridging member. Each belt has a respective
positioning member. The positioning member has two upstanding
walls which are spaced apart and are of a height to extend up
past the oppositel~ facing sides of the bridging member. The
upstanding walls of the positioning member define a sliding
recess between them and each positioning member wall extends up
past and in engagement with the opposed side of the bridging
member. The sliding recess is of a width defined between the
upstanding walls to slidingly receive and engage the oppositely
facing sides of the bridging member in the recess. Thus the
positioning member may be slidingly guided to move along the
bridging member. The recess has a bottom and the bridging
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member bottom side faces toward and is spaced from the bottom of
the sliding recess. A sliding hole at the bottom of the sliding
recess may be shaped and positioned for slidingly receiving and
engaging the projecting pin, thereby further guiding the motion
of the positioning member with respect to the bridging member.
Alternately, guide pin means extending and projecting from one
of the positioning members and the bridging member into the
other of these elements may further guide the respective motion
of these elements. The positioning member includes an engaging
side for engaging and pressing against the first side of the
positioning gear. A spring is located in the sliding recess
engaging the bottom of the sliding recess and the bottom side of
the bridging member. The spring is chargeable by movement of the
bridging member into the sliding recess. The spring is for
biasing the positioning member engaging side against the
positioning gear first side and for biasing the positioning
member away from the bridging member, while the pin is in the
sliding hole and the bridging member is in the sliding recess.
Brief Description of the Drawings
The foregoing and other objects and features of the
invention will be more apparent from the following description
taken in conjunct:ion with the accompanying drawings, in which:
Fig. 1 is an enlarged, cross-sectional, elevational
view of the main part of a printing device in the prior art;
Fig. 2 is a partially exploded side elevational view
of a label printing machine which has a printing device of the
present invention;
Fig. 3 is a partly exploded, side elevational view of
the printing device of the invention;
Fig. ~ is a vertical cross-sectional view of the
printing device;
Fig. 5 is an enlarged perspective view of the main
portion of the printing device;
Fig. 6 is an enlarged cross-sectional, elevational
view of the main part of the printing device of the invention;
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Figs. 7a and 7b are plan views of printed labels in
which the former is printed clearly and the latter is printed
unclearly/ appearing with Fig. S.
Des~ tion of a Preferred Embodiment
A portable label printing machine is equipped with
either a conventional printing device or with the one of the
present invention. In one known label printing machine, as
shown in Fig. 2, there is a printing head 3 that is attached
to forwardly extending yoke arms 4, and the arms 4 are swung
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downwardly by squee~ing a hand lever 2 toward a hand grip 1.
To print a label, the types or stamps 5 that are disposed on
the underside of the printing head 3 are moved into contact
with the label which is placed on a platen 6 attached to the
machine frames 36 and 36'. In another known label printing
machine, the printing head 3 is immovably secured to the
machine frames 36 and 36' of the label printing machine. In
this type of label printing machine, the platen 6 on which a
label sits is moved up by operation of the hand lever ~ so
that the label is brought into contact with the types or
stamps 5 on the underside of the printing head 3.
In the printing head 3 for either a conventional
printing device or for the printing device of the present
invention, as shown in Figs. 3 and 4, selector wheels 8 are
rotated by means of a selector knob 7 and the stamp belts 9
tra~eling around the selector wheels 8 are supported at
their lower portions by positioning gears 11. The stamp
belts are stretched tightly around the wheels 8 and gears
11. Since the position;ng gears ll are subjected to the
action of spring-actuated supporting members 10, the types 5
of stamp belts 9 are held in their printing positions and
the type faces 5 are maintained parallel to the surface of a
label to be printed.
A conventional positioning and supporting mechanism
for stamp belts is described with reference to Fig. l. A
pi~ot shaft 113 is attached to a pair o-f side frames 120 of
a printing head 103. A plurality of positioning gears 111
are independently pivotally secured side by side to the
shaft 113. There is a respective positioning gear 111 for
each stamp belt 109. The belts 109 travel around the posi-
tioning gears 111 in side by side relationship.
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At the upper sidcs of all of the positioning gears
111 are disposed spring actuated supporting members 110.
The springs are charged by the ~autness of belts 109.
Members 110 are comprised o-f a bridging member 114 that is
immcvably secured to and in the space between the frames
120. Each supporting member includes a pin 115, the top end
of which is securely held in a depression at the top of the
bridging member 114, whereby the pin does not move with
respect to the bridging member. A compression spring 116 is
fitted around each pin 115 and its upper end pushes up
against member 114. There is a pushing member 118 above
each gear 111. The pushing member 118 has a sliding hole
117 at its top end to receive the lower portion of the pin
115. Member 118 is urged downwardly by the compression
spring 116 toward the positioning gear lll.
The undersurface of the pushing member 118 is
always spring pressed against the upper surface ll9 of the
positioning gear 111 by the force of compression spring 116.
The position o-f the positioning gear lll and thus of the
type face 105 oE stamp belt 109 is correctly set at the
printing position and at a predetermined angular orientation.
Each pushing member 118 is lifted every time its
positioning gear 111 turns, and the member 118 slides ~erti-
cally along the pin 115. The pushing members 118 are liable
to become wobbly owing to dimensional errors which result
from the wearing of the outer surfaces of the pins 115 and
of the inner walls of the sliding holes 117. Eventually,
the type faces 105 cannot be ma;ntained parallel to the
surface of a label to be printed on the platen. Label
printîng with such misaligned type faces causes the depth of
printing at one side of the printed figures to be different
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from the depth at the other side of the figures, as
shown in Fig. 7b, which makes reading of the characters
difficult.
The printing device of the present invention
has been designed to overcome the above described
disadvantage of the prior art. The printing device of
the present invention maintains the type faces of stamp
belts at predetermined correct positions and also
attains high precision printing on labels without
unevenness of the depth of the printed figures.
The label printing machine shown in Fig. 2
includes a printing head 3. The rear (or right in Fig.
2) portions of the machine frames 36 and 36' are
elongated to form a hand grip 1. Below the hand grip
1, a hand lever 2 is pivotally secured to grip 1 at a
shaft 35. The front portion of the hand lever 2 is
elongated to form a pair of bifurcated yoke arms 4. In
the space between the free ends of the yoke arms 4, a
printing head 3 is disposed with set screws 34.
As shown in Figs. 3 and 4, the printing head
3 comprises a printing head casing 19, a pair of spaced
apart frames 20 tha~ are attached to head casing 19, a
front cover 21 at one side, a rear cover 22 at the
other side, a printing angle adjusting section Z3 that
is attached to the frames 20 and the -front cover 21,
and side plates 12 that are fixed to a pair of the yoke
arms 4 of the label printing machine. The front cover
21 and rear cover 22 are attached to both side plates
12 by shafts 21a and 22a. The angle at which the type
faces 5 of the stamp belts 9 strike the labels can be
adjusted by manipulating the adjusting screw 24 of the
angle adjusting section 23.
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The group oE endless stamp belts 9 are held within
the printing head casing 19 and are stretched around upper
type face selector wheels 8 that are arrayed side by side
and around lo~er position;ng gears 11 that have spring
actuated supporting members lQ that are disposed between the
frames 20. Each selector wheel 8 has internal gear teeth ~5
which are engageable by an engaging piece 27 that is attached
to a selector shaft 26 having a selector knob 7. By axial
movement of shaft 26 using knob 7, the engaging piece 27 is
moved into a partlcular wheel 8, and rotation of knob 7
rotates the selected wheel 8. With this mechanism, any
desired selector wheel 8 can be rotated so as to move its
stamp belt 9 lengthwise.
Each of the stamp belts 9 is endless. One-half of
the outer surface of the belt is provided with printing
types 5 and the other half carries visible indicating figures
28. The indicating figures 28 can be observed through a
window 29 that is formed in the upper part of the printing
head casing 19~ Stamp belts 9 are flexible, but essentially
nonstretchable.
Referring to Pig. 6, thre is a positioning and
supporting mechanism or the stamp belts 9 at the lower
portion o~ the printing head 3. The positioning gears 11
are supported in side by side relationship by a pivot shaft
13 which is attached to and extends between the frames 20.
On each of the four outer sides of the square positioning
gear 11, there is an engaging recess 31 which is brought
into engagement with a correspondingly shaped en~aging
projec~ion 30 that is formed on the inside surface of the
stamp belt 9~
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l`here are spring actuated supporting Members 10
which are disposed ~bove the positioning gears 11. Members
10 comprise a s;ngle bridging member 14 which is fixed to
and exten~s completely between the frames 20. There are
pins 15 whose upper ends are attached to the bridging member
14. Compression springs 16 are disposed around the pins 15.
The lower ends of pins 15 project beneath the bridging
member. There are pushing members 18 which are always
pressed toward the positioning gears 11 which are below the
members 18.
Sliding recesses 32 formed in pushing members 18
receive the bridging member 14. Sliding holes 17 in members
18 recei~e the pins 15, and the upper ends of the holes 17
communicate with the sliding recesses 32. The springs 16
press against the top of the bottom recess in bridging
member 14 and against ~he bottoms of the recesses 32.
Pushing members 18 are pushed down by the compression springs
16.
To facilitate the smooth turning of the positioning
gears 11, the undersurface 33 of each pushing member 18 is
rounded concavely.
The operation of this supporting member is now
described. When a selected stamp belt 9 is moved around by
the selector knob 7, the positioning gear 11 is rotated~
because the engaging recesses 31 of the positioning gear 11
; are in engagçmen~ with the engagi~g projections 30 of the
stamp belt 9~ The corner 37 of the positioning gear 11 that
is just belo~ the pushing member 18 pushes up on its concave
undersurface 33. This moves the pushing member 1~ up and,
once a flat side of the gear 11 is again beneath undersurface
33, pushing member 1~ moves down under the force of the
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compression spr;ng 16. Movcment o the pushing member 18 is
along the outer surfac~ o-f the pin 15 and along the side
walls 38 of the bridging member 14. This motion is repeated
until a desired type 5 has been shifted to the printing
position in the lowermost part of the printing head 3.
In comparison with the conventional structure
shown in Fig. 1, the printing head 3 of the present invention
is characterized in that the bridging member 14 is made
thinner from side to side and the pushing members 18 are
made taller. Each pushing member includes upstanding spaced
apart side walls which define the sliding recess 32 between
them and these side walls extend up along the sides of the
bridging member. Furthermore, both the pins 15 and the side
walls 38 of the bridging member 14 are slidably engaged in
the pushing members. Since the areas of the sliding surfaces
of the pushing members 18 are increased and the sliding
surfaces are elongated in the vertical direction, the printing
head 3 can be protected against the influence of the wear of
the engaging surfaces and the dimensional errors in making
the device. In other words, even when the same size gaps
are formed between contact surfaces owing, for example, to
wear, the inclination of the undersur-face of the pushing
member 18 in the present invention relative to the horizontal
plane is very small as compared Wit}l the conventional mechanism
shown in Fig. 1, so that the positioning gear 11 that is
always depressed br this pushing member 18 and the face of
type 5 of the stamp belt 9 in the printing position are
maintained at the correct position and orientation. As a
result, printing of a label can be always performed by a
type face that is parallel to the label on the platen 6 so
that a quite clear and precise imprint, without fluctuation
of printing depth can be obtained, as shown in Fig. 7a.
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Furt]ler, the present invention is especially
advantageous where a vertically tall area must be printed,
such as in bar code printing (shown in Fig. 7) and multiline
printing (not shown).
Although the present invention has been described
in connection with a preferred embodiment thereo~, many
variations and modifications will now become apparent to
those skilled in the art. It is preferred, therefore, that
the present invention be limited not by the specific disclosure
herein, but only by the appended claims.
