Incremental printing of symbolic information – Ink jet – Combined
Reexamination Certificate
2001-01-23
2002-04-16
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Combined
C101S036000
Reexamination Certificate
active
06371585
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a ring-mark printing device for identifying electrical cables. When ring marks are to be painted on the circular surface of an electrical cable, the operation is preferably carried out under non-contact conditions. The electrical cables painted with ring marks are usually employed in the automobile industry, and the ring marks serve to distinguish the quality and/or size of such cables.
2. Description of Background Information
Known ring-mark printing devices usually employ either a printing system in which ink is ejected through ink nozzles under pressure and painted on a cable surface, or a system in which a marking drum is provided with a tubular surface having ink nozzles, through which ink is ejected by the centrifugal force exerted by drum rotation.
An example of the former (first) printing system is disclosed in a Japanese utility model application published under No. SHO 61-60413, and an example of the latter (second) system is disclosed in a Japanese utility model application published under No. HEI 7-25517.
FIG. 1
shows process steps performed by the second printing system, in which an electrical cable is manufactured and then painted with ring-like marks. In this system, a conductor wire
2
is continuously supplied from a supply reel
1
along a predetermined path. The conductor wire
2
is then passed through an extruding machine
3
and coated while being extruded, thereby yielding a coated electrical cable
4
. The coated electrical cable
4
is guided into a printer machine
5
, in which the cable is painted with ring-like marks used for cable identification. The marked electrical cable
4
is cooled in a cooling bath
6
, withdrawn through a withdrawal unit
7
, and reeled continuously around a receiving reel
8
.
FIGS. 2
,
3
and
4
illustrate the following device units: a printer box
10
, in which the electrical cable
4
is subjected to a printing operation; a pair of marking drums
11
and
12
mounted in the printer box
10
, the two marking drums being arranged sequentially along the cable's feed axis, and in staggered positions and at some distance relative to the feed axis; a driving mechanism for rotating both marking drums
11
and
12
(not shown in the figures); an ink tank
13
for storing marking ink; an ink-supply mechanism for feeding ink from the ink tank
13
to inside the marking drums
11
and
12
through a supply pipe
14
; and an ink return pipe
15
for forwarding the ink contained in the printer box
10
to the ink tank
13
.
As shown in
FIGS. 5 and 6
, the marking drums
11
and
12
respectively include a plurality of ink-jet nozzles (six nozzles in the illustrated example) arranged at a given interval in the circumferential direction of the tubular surface. The ink
16
stored in the marking drum
11
is ejected through each ink-jet nozzle, by virtue of the centrifugal force generated by the rotating drum, so that each half side face of the electrical cable
4
, when advancing along the feed axis P, is painted with ejected ink.
FIGS. 3
to
7
show the marking process in detail. When the electrical cable
4
advances along the feed axis P of the cable and passes in front of a first marking drum
11
, a first semicircular side face of the cable
4
is painted with ink
16
ejected from the marking drum
11
placed upstream, and is printed with a semicircular mark
17
a
(FIG.
5
). Likewise, when the electrical cable
4
advances further and passes in front of a second marking drum
12
placed downstream, a second semicircular side face of the cable
4
is painted with ink
16
ejected from the marking drum
12
, and is printed with a semicircular mark
17
b
(FIG.
6
). In this manner, the outer circular face of the electrical cable
4
can be printed with complete ring marks
17
(or band marks) at a given interval.
In order to match the position of the first semicircular mark
17
a
with that of the second semicircular mark
17
b
, the marking drums
11
and
12
are driven in synchronization.
In such a centrifugal printing system, equipment is designed with the presumption that the ink
16
continues to be ejected correctly. Accordingly, when electrical cables
4
with and without ring marks are produced in the same production line, either the printer device
5
is cut off, or a special ink-shield is installed for deviating ejected ink
16
from the electrical cable
4
.
Thus, when the centrifugal printing system is applied, the printer device
5
may optionally be turned off when the electrical cables are to be processed without printing. However, this switching off process involves a certain time lag before the rotational speed of the marking drums
11
and
12
can be lowered to a point where the ink
16
stops jetting out. As a result, the portion of electrical cables
4
processed during the switching off time must be cast aside as a substandard product. Conversely, when the marking drums
11
and
12
are again put into motion, it takes a while to regain full rotational speed and stability. The portion of electrical cables
4
produced during this period must also be cast aside as a substandard product. Those substandard products formed during the restarting period may reach several kilometers of the electrical cable
4
, which is cast aside as a length loss.
When the marking drums
11
and
12
are immobile for a long time (the standstill duration limit being several minutes to some fifteen minute), ink
16
solidifies inside the ink-jet nozzles. The disassembling and cleaning of the nozzles will thus become necessary when the marking drums are to be started.
When a special ink shield is used, it must be replaced during a replacement standstill. Such a standstill incurs of course the production of substandard electrical cables, resulting in a length loss of several hundred meters. Moreover, ink
16
may be spattered around from the marking drums
11
and
12
while the shield is replaced, and may smear peripheral equipment. As the ink
16
contains organic solvents, the working environments are also deteriorated.
Moreover, when the shield is replaced, it may inadvertently thrust the electrical cable
4
, and cut it off.
In order to reduce such accidents, prior art solutions usually opted for preparing different production schedules, depending on whether electrical cables
4
are printed with ring marks or not. However, such production methods are not well suited to small-lot production and suffer from a low running rate of the production line.
SUMMARY OF THE INVENTION
In order to solve the above-noted problems, the present invention provides a ring-mark printing device for identifying electrical cables, which reduces the length loss of the electrical cables, improves the running rate of the production line of the cables, and is suited to small-lot production.
To this end, there is provided a ring-mark printing device for identifying electrical cables. The device includes a printer box having a feed axis and configured to pass an electrical cable along the feed axis and a pair of marking drums with a respective outer circular face. The marking drums are contained in the printer box and arranged in staggered positions along the feed axis and at a given distance away therefrom. Further, the marking drums include ink-jet nozzles at the outer circular face. Further yet, the marking drums are respectively adapted to contain ink and eject the ink through the ink-jet nozzles by virtue of centrifugal forces exerted by drum rotation, in order to print the ring-mark around the circular surface of the electrical cable.
According to the present invention, the printer box is provided with an ink shield including substantially concentrically positioned outer and inner tubular bodies which are configured to surround the electrical cable from a given distance. The outer tubular body further includes at least one outer ink-orifice at a position facing one of the marking drums and the inner tubular body includes at least one inner ink orifice.
The inner
Barlow John
Greenblum & Bernstein P.L.C.
Stephens Juanita
Sumitomo Wiring Systems Ltd.
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