Bar code printing device

The disclosure concerns a bar code printing device for use with the printing head of a portable label printing and applying machine, or the like. A plurality of juxtaposed index rings are selectively turned by a selecting member and each index ring turns a corresponding meshing bar code type ring into a selected printing position. The type rings are also juxtaposed. A rotary member is also turned by the selecting member for causing straight line reciprocating movement of an actuating member across the axis of the rotary member and this in turn moves a thrust member in the axial direction of the type rings. The thrust member is moved to bias the type rings during the printing operation so that the type rings are forced into close contact. The thrust member is also moved to permit the type rings to be left as they are, during the imprintable type selecting operation, so that the type rings are spaced by gaps which facilitate the selective rotation of the rings by the selecting member.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a printing device for printing bar codes 
which can be omnidirectionally read out in an automatic manner by means of 
an optical reader, and more particularly to improvements in a bar code 
printing device which is used with a portable label printing and applying 
machine or a table type automatic label printer, or the like, so that it 
can print bar code on a series of composite labels each composed of a 
label and a sheet of backing paper. 
2. Description of the Prior Art 
Representative printing devices of this kind are disclosed in U.S. Pat. 
Nos. 4,018,157 and 4,155,302, both by the inventor hereof. 
Recently, the so-called "POS" (Point-of-Sale) system has been put into 
practice in large size supermarkets. In one type of bar code, as shown on 
label L in FIG. 1 of the drawings hereof, one numeral is composed, in 
combination, of two dark bars having a height of 14 mm and two light 
spaces, both of which are arranged in parallel to constitute one character 
(or seven modules). The character thus constituted is required to have a 
width of 2.31 mm with an allowance of .+-.0.101 mm. 
The bar code printing device has a plurality of bar code rings juxtaposed 
side by side on a common axis of rotation. Each of the bar code type rings 
is formed with a set of numerals. Each numeral is composed of dark and 
light bars having sizes selected to correspond to the particular numeral. 
The bar code numeral is made highly accurate. 
However, there are problems in establishing precise gaps between the type 
rings, which are axially juxtaposed. Even the one light space which is 
left at one end of each bar code type ring plays an important role as a 
symbol. Therefore, an unnecessary gap between two adjacent type rings 
would cause an incorrect number to be read out by the optical reader. On 
the other hand, when the respective bar code type rings are pushed 
together in fixed contact, a desired ring cannot be selectively turned to 
change the numeral thereon. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide a printing 
device which is free from the disadvantages of the prior art. 
Another object of the present invention is to provide a highly precise 
printing device. 
A further object of the invention is to assure that the gaps required for 
ensuring smooth rotation of the bar code type rings are established 
between the adjacent type rings, when any of them is to be selectively 
turned. 
Yet another object of the invention is to assure that the gaps for smooth 
rotation of the type rings are eliminated when the bar code type rings are 
to be used for printing purposes, thereby to force the type rings into 
fixed close contact so that widthwise errors in the printed multi-numeral 
bar code may be minimized. 
The present invention provides a bar code printing device. There is a 
plurality of index rings axially juxtaposed to one another in a manner to 
rotate independently of one another. A selecting member selectively turns 
any of the index rings into a desired position. There is a corresponding 
plurality of bar code type rings which are juxtaposed to one another, and 
each meshes with a respective index ring. Any type ring can be rotated to 
a selected position by the corresponding index ring. A rotary member is 
disposed at the end of the row of index rings. The rotary member is 
adapted to be turned by the selecting member. There is an actuating member 
that is adapted to be moved, preferably in straight line reciprocating 
motion across the axis of the rotary member, by the rotary member. There 
is a thrust member having an elasticity and adapted to be actuated in the 
axial direction of the row of bar code type rings by the actuating member. 
During the printing operation, the thrust member elastically thrusts the 
bar code type rings into close contact. During the bar code selecting 
operation, the thrust member leaves the bar code type rings as they are, 
so that said bar code type rings are spaced by gaps for facilitating 
selective rotation of any type ring.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION 
The bar code printing device according to the present invention is now 
described. Referring to FIGS. 2 and 3, the shell of a bar code printing 
head 10 is comprised of a casing 11 and a cover frame 12, in which are 
accommodated both a group of eight bar code type rings 17 axially 
juxtaposed to one another and a group of eight index rings 13 also axially 
juxtaposed to one another and meshing with the type rings 17, 
respectively, thereby to make it possible to print the bar codes. 
The index rings are disposed at an upper portion of the printing head 10. 
Each of the rings 13 is formed on its outer circumference with ten 
external teeth 14, and on the remainder of the outer circumference or 
between the external teeth 14 with ten index numerals 15 from "0" to "9". 
At its center each index ring 13 has a hole through it which is defined 
and surrounded by internal teeth 16. The teeth can mesh with the pinion 
gear 30 of a selecting member 29, described below. 
The bar code type rings 17 are disposed at a lower portion of the printing 
head 10. Each type ring 17 has indentations 18 on its outer circumference 
which mesh with the external teeth 14 of the rings 13. On the remaining 
outer circumference of the ring 17 or between the indentations 18, the 
ring 17 has printing surfaces which are formed with bar codes 19. 
There are ten printing surfaces giving the ring 17 a decagonal shape. Each 
side of the ring 17 is formed with a respective bar code 19 and each such 
bar code corresponds to a respective index numeral 15 of the 
afore-mentioned index ring 13. The bar codes 19 and the respective 
numerals 15 are so placed that when a particular numeral on the index ring 
is at a viewing location, described below, the corresponding bar code is 
at a printing location at a printing surface. Moreover, each side of the 
ring 17 has a printing surface which is set to protrude from a bar code 
printing aperture 59 that is positioned just below the printing head 10. 
The bar code type ring 17 has an opening through its center which is 
defined by and surrounded by internal teeth 20, and in which is fitted a 
respective bearing member 21 that is mounted rotatably on a main shaft 56. 
Each bearing member 21 includes a first pair of elastic, circumferentially 
extending, oppositely directed top retaining arms 23 and includes a second 
pair of circumferentially extending, oppositely directed and opposed, 
lower elastic arms 24 which are separated at a cut portion 25. Each of 
arms 23 and 24 are sized and shaped to elastically mesh and engage with 
the inner circumference of and the inner teeth of the corresponding bar 
code type ring 17. The paired retaining arms 23 ensure there is indexed 
rotation of the corresponding type ring 17 when the type ring is to be 
selectively turned because the lobes at the ends of the arms 23 engage in 
the teeth of the ring 17. The paired elastic arms 24 absorb the impact on 
the corresponding type ring 17 when the ring is moved to print. For this 
purpose, the arms 24 extend around the bottom of the ring 17. Further 
details of the bearing members 21 are described below. 
Each bearing member 21 has pair of pins 26 formed on one side thereof and a 
corespondingly shaped and positioned pair of holes 27 on the other side 
thereof so that the adjoining bearing members 21 are formed into a block 
by the engagements of the pins 26 and the holes 27. The bearing member 21 
has a center hole therethrough, in which is fitted the main shaft 56. That 
shaft is fastened to the side frame of the casing 11 and to the cover 
frame 12 by screws. As a result, the bearing members 21 are supported on 
the main shaft 56 so that the bar code type rings 17 and accordingly the 
afore-mentioned index rings 13 are made rotatable. 
The type selecting member is in the form of a sleeve shaped shaft 29. It is 
to be brought into engagement with a desired one of the index rings 13 for 
selectively turning it. The selecting sleeve shaft 29 is fitted on a guide 
shaft 28 which is mounted on the casing 11, and the shaft 29 can slide in 
the axial direction of the shaft 28. The selecting sleeve shaft 29 has a 
pinion gear 30 at its leading end and the gear 30 is brought into meshing 
engagement with the internal teeth 16 of the selected index ring 13. The 
stem portion of the selecting sleeve shaft 29 extends through a guide hole 
31 which is formed in the cover frame 12. On the other end of the sleeve 
shaft 29 from the gear 30, there is a selecting knob 34. An indicator 32 
is rotatably supported on the shaft 29. The indicator includes a pointer 
33 for indicating the index numeral 15 of the index ring 13 selected. 
The index numerals 15 of the index rings 13 and of a later-described rotary 
member 39 are manually rotated by knob 34 while being observed through an 
index aperture 38 which is formed in the top of the printing head 10. The 
pointer 33 is guided to indicate the selected numeral showing at the 
aperture 38. 
The selecting sleeve shaft 29 has a plurality of circumferential grooves at 
spaced intervals along its length which regulate the axial movement of the 
sleeve shaft 29 to any preset axial position. Regulation of the axial 
movement of the sleeve shaft 29 is effected by selective engagement 
between one of the grooves and a pressure member which is mounted in an 
upper portion of the cover frame 12. The pressure member is comprised of a 
steel ball 35 which is urged against the shaft 29 by a coil spring 36 that 
pushes off a stop screw 37 in the cover frame 12. 
At the opposite side of the index ring group 13 from the knob 34 and 
coaxial with the selecting sleeve shaft 29, there is disposed the rotary 
member 39 which is made coactive with the sleeve shaft 29. The rotary 
member 39 has an opening through it which is formed with internal teeth 40 
that are sized and shaped to mesh with the pinion gear 30 of the sleeve 
member 29. The rotary member 39 has the indications "Select" 41 and 
"Print" 42 formed on its outer circumference. 
An actuating arm 44 is mounted on the rotary member 39 to rotate therewith. 
The actuating arm has a mounting stud 45 which is fitted in the mounting 
hole 43 in the member 39. The other end of the actuating arm 44 is 
profiled to define a pinion 46 for meshing with the rack 48 of an 
actuating member 47, and the actuating member 47 is moved up and down with 
respect to the printing head 10. Such motion either forces the bar code 
type rings 17 into close contact for printing or leaves those rings as 
they are, with gaps between them. 
The actuating member 47 is arranged at the opposite end of the bar code 
type ring group 17 from the knob 34. The actuating member has a slot 49 
formed at its lower portion, in which the main shaft 56 is loosely fitted. 
The side surface of the actuating member 47 facing the type ring group 17 
is formed with upraised land surfaces 51a and 51b which are each formed at 
both of their top and bottom sides with tapered surfaces 50a and 50b. 
A thrust member 52 is sandwiched between the actuating member 47 and the 
end of the bar code type ring group 17. On the side of the thrust member 
52 facing toward the actuating member 47, tapered surfaces 55a and 55b are 
formed (see FIG. 8). They taper, in the thickness dimension of the member 
52, toward the periphery of that member. The surfaces 55a and 55b are 
sized and shaped and oriented to engage with the tapered surfaces 50a and 
50b of the actuating member 47. 
On its outer surface facing toward the type ring group, the thrust member 
carries two pairs of elastic flaps 53 which are punched out from the 
thrust member and apply an elastic thrust to the aforementioned type ring 
group 17. For this purpose, the elastic flaps 53 are formed with 
projections 54 at their leading ends. 
The actuating member 47 is received in and guided for sliding movement in 
the vertical direction by a vertical guide groove 58, which is defined by 
the crescent shaped thrust pads 57 that are mounted on the side frame of 
the casing 11. 
Since the bar codes must be highly precisely and clearly printed, a 
cleaning member 60 is attached to the printing head 10 for removing ink or 
dust. The cleaning member 60 has a brush 61 at its center and has two 
attaching portions 62 at both sides, at which the member 60 is removably 
attached to the frames of the printing head 10. Thus, the brush 61 is 
brought into abutment against the selected bar codes 19 of the respective 
bar code type rings 17 so that the bar codes 19 may be cleaned when the 
respective type rings 17 are selectively turned. 
The selecting and printing operations of the bar code type rings 17 are now 
described. The selecting operation for the bar code type rings 17 is 
described with reference to FIGS. 4 and 6 to 8. Start with the printing 
head in the printing condition. The pinion gear 30 of the selecting sleeve 
shaft 29 is in meshing engagement with the internal teeth 40 of the rotary 
member 39 and the "Print" indication 42 is being pointed at by the pointer 
33 of the indicator 32. This is the condition shown in FIG. 4. The 
selecting sleeve shaft 29 is manually turned clockwise, as viewed in FIG. 
6, by a preset angle so that the rotary member 39, now meshing with the 
shaft 29, is accordingly turned clockwise until the pointer 33 indicates 
the "Select" indication 41. This rotation of the rotary member 39 raises 
the actuating member 47 with respect to the printing head 10, as shown in 
FIGS. 6 and 7, in synchronism with the rotations of the rotary member 39 
and the actuating arm 44. 
As a result, the tapered surfaces 50a and 50b of the actuating member 47 
engage the corresponding tapered surfaces 55a and 55b of the thrust member 
52, which had been thrusting the bar code type rings 17 together, thereby 
to release the thrust force so that gaps G are established between 
adjacent bar code type rings 17 which are juxtaposed to one another. The 
gaps G permit individual type rings 17 to be selected and rotated without 
difficulty by moving the selecting knob 34 in the axial direction until 
the teeth on the pinion 30 mesh with the teeth inside a selected index 
ring 13 and by then turning the knob 34 which turns the index ring 13 and 
its corresponding type ring 17 so that the desired bar code on that ring 
17 can be rotated into the printing position. 
The selecting knob 34 is slid in the axial direction, until the pointer 33 
of the indicator 32 indicates the index ring 13 to be selected. The knob 
34 is then turned which turns the selected index ring, until the pointer 
33 comes to indicate the desired index numeral 15. This thereby selects 
the desired bar code 19 on the ring 17. 
To thereafter perform the printing operation, after the selection of the 
desired types on the type rings 17, the selecting knob 34 is forced, as 
shown in FIG. 4, all the way into the printing head 10 so that the rotary 
member 39 is engaged by the gear 30. The knob 34 is turned 
counter-clockwise as viewed in FIG. 6, by a preset angle until the pointer 
33 indicates the "Print" indication 42 on member 39, which locks all the 
bar code type rings 17 in position. 
In response to the rotation of the selecting sleeve shaft 29, the rotary 
member 39 and the actuating arm 44 move the actuating member 47 down as 
shown in double-dotted lines in FIG. 6 and in FIG. 7. The tapered surfaces 
50a and 50b of the actuating member 47 slide on the tapered surfaces 55a 
and 55b of the thrust member 52, until the former surfaces are disengaged 
from the latter, so that the land surfaces 51a and 51b on the actuating 
member are brought into abutment against the side of the thrust member 52. 
As a result, the projections 54 at the leading ends of the elastic flaps 
53 of the thrust member 52 elastically bias the end of the row of bar code 
type rings 17 to urge the rings together, thereby to eliminate the gaps G, 
which were established during the selecting operations, as shown in FIG. 
7, so that all of the type rings 17 are forced into close contact. This 
provides the precise width light spaces of the complete bar codes. 
Although the actuating arm 44 with the pinion 46 is shown sandwiched 
between the actuating member 47 and the rotary member 39, the present 
invention contemplates a modification in which the rotation of the rotary 
member 39 is sufficiently transmitted even if the rotary member 39 is 
formed with a pinion which is sized and shape to directly mesh with the 
rack 48 of the actuating member 47. 
Referring to FIG. 9, each of the bearing members 21 is made of an elastic 
synthetic resin, and it is fitted in the internal teeth 20 of the 
corresponding one of the bar code type rings 17, which are also made of a 
synthetic resin. The upper or arm portions of each bearing member 21 is 
formed integrally with the paired elastic retaining members 23, which are 
sized and shaped, e.g. by having lobes at the ends thereof, to mesh with 
the internal teeth 20 of the corresponding type ring 17 thereby to ensure 
the reliable indexed rotation of that type ring 17 when the latter is to 
be selectively turned. On the other hand, the lower or leg portions of the 
bearing member 21 integrally carries the paired elastic members 24 which 
are split by the cut portion 25 so that their ends are opposed. They are 
sized and shaped to engage with the internal teeth 20 of the type ring 17, 
thereby to absorb the shocks of the type ring 17 when the latter is to be 
brought into its printing operation. The elastic members 24 are at the 
bottom since printing of the bar codes is accomplished by moving the 
printing device downwardly, and the members 24 are positioned for opposing 
the force upon the bearing member upon movement of the printing device for 
printing a bar code. 
In FIG. 10, the respective bar code rings 17, having been selectively 
turned, now have their selected bar codes 19 arranged on their surfaces 
under more or less irregular conditions. When the label L is printed, the 
resultant print by the floating and/or upraised bar codes is thin, whereas 
the print by the depressed bar codes is crushed, so that the total bar 
code print is incomplete. 
As shown in FIG. 11, therefore, at the instant when the irregularly grouped 
bar code type rings 17 are printed, the printing surfaces of the bar codes 
19 are regularly arranged by the elastically shock-absorbing effects of 
the two elastic members 24 at the bottom sides of the bearing members 21, 
so that desirable uniform prints can be attained. 
Shock-absorbing effects have not been so high according to the prior art 
because the leg portions of the bearing members of similar kinds are not 
split as at 25. With the present invention, however, better 
shock-absorbing effects can be obtained. 
Thus, the present invention produces the following effects. 
(1) To move the plural bar code type rings in the axial direction either to 
force them into close contact or to disengage them, the actuating member 
with the tapered surfaces thereon is made vertically movable in 
cooperation with the selecting member and the rotary member, and these 
vertical movements are transmitted to the thrust plate which is made 
movable in the axial direction of the type ring group. As a result, the 
upward and downward sliding movements of the actuating member can be 
ensured more than in the conventional system of U.S. Pat. No. 4,018,157 in 
which the tapered surface of the knob is brought into engagement with the 
pin of the thrust plate. 
As another result, the thrust application and release of the respective bar 
code type rings in the axial direction are ensured so that the type rings 
can be forced into close contact without difficulty and so that the gaps 
between the type rings for enabling their rotation can also be established 
without difficulty. 
(2) The thrust member is slidable in the axial direction of the bar code 
type ring group to apply and release the thrust to and from the type 
rings. The thrust member is formed with integral elastic flaps. As a 
result, the close contact between the type rings can be stabilized more 
than is possible with the conventional system of U.S. Pat. No. 4,018,157. 
Thus, the desired highly precise prints of the bar codes can be ensured. 
(3) The bar code type ring group is thrust in the axial direction. As a 
result, the close contacts between adjacent type rings can be averaged 
more than with the conventional system of U.S. Pat. No. 4,018,157, in 
which the thrust to be exerted upon the type rings is axially established 
by the turning operation. Thus, better fastening action is attained so 
that more highly precise prints of the bar codes can be obtained. 
The present invention may be embodied in other specific forms without 
departing from the spirit or essential attributes thereof and, 
accordingly, reference should be made to the appended claims, rather than 
to the foregoing specification, as indicating the scope of the invention.