Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02304520 2000-03-22
LARGE FORMAT INK-JET COLOUR PRIr.ITER
Field of the Invention
The inverition rE~iates to the field of ink-jet
printers used for colour printing of large format
articles used, in particular, in the advertisement
industry.
Background Art
A specific feature of the utilization of ink-jet
printers used for colour printing of large format
articles is the ;producaion of large size images (up to
tens of square meters) of sufficiently high quality at
relatively low cost, which is attained by creating
highly-productive machines with relatively low
resolution of the produced images (usually 18-36 lines
per inch ). In a principle respect these devices are
riot distinctive over ordinary printers that are widely
used as documenting devices in personal computers (PC) .
typical re~reser~tative of such devices- is an ink-
jet printing head and a printer cornpri~ing a paper
feeding device, a carriage executing reciprocal movement
along a paper substrate, and a removable jet head with a
reserve of ink that i~a mounted on zhe car_wiage (EP, ?~2
X400652, 1990, B 41 ,T 2/07) . The head is made in the
form of an autonomou:5 unit having an electronic unit in
which information relating to the mutual p ositioninu of
the drawing nozzles ir: the head is entered_ these
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nozzles are used by the control program of the PC when-
information is feed ~ro:m the PC to the prir_ter .
The prOCesS Of drawing is carried out by supplying
energy to each ;ZOZZle~ of the head in the form of an
S electrical pulse which is ccnverted into heat sufficient
to discharge a portion of ink from the nozzle.
Furthermore, a system for synchronizing the position of
the head relativ~s to the substrate anti the information
being presented is used in the printer.
From a principlsa point of view, all printers
operate according to t:zis arrangement,. differing only by
the method of applying the image (eithe~~ by heat, or
hydraulic impact, or b.Last of air, etc _ ) _
z~ll of the basic: elements of such printers are
present in the device: disclosed in the patent US, A
4999651, 1991, G Ol D :15/16. In a colour recorder, in k
cartridges are positioned on a common carriage that
effects reclproc_al mo~rement. There are also
intermediate wor~:ing cartridges in which the level of
the ink is maintained virtually constant, which ensures
the highest quality of the ~mages being reproduced.
Furthermore, the device contains an electronic unit
which holds the i:magn b eir_g reproduced in its memory and
controls the oper~~tion modes of Lhe device.
The presence of ein intermediate unit for Stori.rig
the information to be applied makes it possible to
separate in time the generation of images in a PC (for
example, by scanning photographic imagas and then
Editing them, or producing images by machine graphic
methods, etc.) and their transfer to tr.e substrate.
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Furthermore, the volume of the informzstior: stored in the
device only depends or~ its own capabilities and is in no
wc~y related to the PC, which makes it possible to use
this device in network systems.
The presencE~ of ink cartridges d~~ectly on the
carriage simplifies t;he construction of the device,
ensuring at the same tame the possibility of obtaining a
larger volume of graphic material without frequently
recharging the device., As already noted above, the
presence of an intermediate service cartridge er_sureS a
constant level of the ink, which promotes effective
operation of the jet elements and a high duality of the
images being reproduced.
A device is known that serves to obtain a direct
image on one side: of a sheet and a mirror' image on the
_other side, which makes it possible to obtain a high
quality image or.~ a semi-transparent material (US, A
5376957, 1994, B 41 J 2/095) . This device is provided
with an ink-feeding mechanism with two carriages
2o positioned on opposite sides of a substrate. Control
of the operation of tree device and, in p~.rticular, tr.e
carriages and heads, is carried out with the aid of a
unit for control and storage of the dire~~t and mirror
images being formed. Hy means of a Scanner,
?S information is er..tered into a computer wh ich edits the
image and encodes> the print density of each colour in
the form of els:ctrical current pulses of different
width, which control e7_ectric valves of the atomizers ef
the jet heads of each colour, which are on. the ink-jet
30 printing device. Thus, the density of each colour is
~.
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determined by the - width of the pulse ge_zerated by the
FC. Specific features of the operation of ink-jet
e-~ements of the heads are that the air stream entering
the working nozzle of the jet element consists of twe
S streams : one - continuous, creating a cor_stant s Cream of
air in the nozz7_e, which ensures that the ink ir: the
supply channel does not dry and hir_ders the formation of
parasitic drops at the end of that channel, and the
seccnd - controlled with the aid of an air valve which
cpens ar_ additional si~ream of air, ensur=ng the supply
ef ink to the substrate in accordance with the width of
the control pul;;es. In order to ensure reliable
adhesion arid drying and to exclude smearing of the ink,
the substrate is heated with spiral heaters which are
mounted below and above the carriages in the direction
of movement of the substrate. Sponges are also
disposed on the carriages, the sponges wiping the
substrate before the ink is applied ~~hereon, this
ensuring removal of foreign contaminants and also
enhancing application of the ink onto the ~ubstrate.
However, ths~ presence of lines in each moving
car riage should be noted in This construcv.ion . These
lines consist of a plurality of electrical cables, for
control of the valves in the heads, amd tubes for
feeding zhe ink. Th:~s line increases as the width of
the substrate, along which the carriage moves,
increases, and this line has to move toge~:.her with the
carriage, which creates a number of technological
difficulties and :reduces the reliability of operation of
the device. -
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. Reciprocal movement of the carriages presumes
acceleration to ~~he nominal speed, braking and stopping
fox each working cycle, which reduces the productivit y
of the devioe and requires increased power of the drive
mechanisms and corresponding braking dampers.
Furthermore, with horizontal positioning of the heads of
different colour;; from the left to the right and from
the right to the left, the sequence in which the primary
colours are applied is disturbed, whiciZ results in
"striping" (by shade) of the obtained irnag8s. There is
also a problem in obtaining quality- two~sided images,
the solution. to this problem not being found in prior
art. In particular, dzfferen~ heads, positioned on
different carriages, a re used in the making of d~.rect
ar.d mirror image's . It is virtually impossibly to
ensure ~cheir complete identicality in operation.
Therefore, when two-sided images are being produced,
distortions inevitably occur in the colour reproduction,
and this affects the quality of the article:.
Disclosure of the Invention
The problems be:W c~ solved in the invention are the
fcllow.ing:
- liquidatio:n of the lines connecting the carriage
to the systems for supplying control signals, air and
ink:
- ensure the suc:Cessive application o- the primary
colours
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- suppression of colour aberrations where printing -a
semi-transparent substrate on both sides:
- ensure the precise application of the ink onto
the substrate;
- ensure the possibility of simultaneously
performing one-sided printing on two substrates.
In order t o achieve the aforesaid technical
results, the construction of a large format ink-jet
colour printer is proposed which comprises a subsi:rate
feeding system, an ink feeding mechanism which is
movable along a closed guiding rail relative to the
substrate, this making it possible for heads to travel
around the substrate on two sides, and a printer con trol
unit. Shafts. in the substrate feedi.zg system are
positioned in a vertical plane, wherein tensioning
shafts, connected ._o reversible motors by means of
magnetic clutches, are positioned above ~~nd below the
feeding shaft provided with a reversible motor. The
ink feeding mechanism, movable along the closed guiding
rail is provided with at least one carriage with brushes
for supplying electric power, with a rE~eiver -~o be
filled with air from an external source by means of a
rapidly-released catch, with a controller provided with
a transceiver, and with an optical sensor electrically
?5 coupled to the contr oiler. The guiding rail is
provided with busbars for supplying elect=is power and
with a hatched ruler for exactly positioning the
carriage. Wherein, electrical valves connected to the
printer control 'unit are mounted between the charging
cartridges,- positioned on the carriage and having a
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level sensor, and the rapidly-released catches of the
system for recharging those cartridges. The rapidly-
released catches are positioned in places where the
guiding rail turns. In order to increase the productivity
there may be two and more of such carriages. The
carriages move at a constant speed, which reduces the
power of the drive mechanisms and eliminates the need for
dampers, since movement of the carriages takes place in
one direction (for example, in the clockwise direction),
removes the question of "striping" in the obtained
images, and the colour palette of the direct and mirror
images is also the same. Wherein, full autonomy of the
carriage is ensured upon its movement over the working
sections of the substrates.
The printer may have a second substrate feeding
system, independent of the first, wherein both parallel
positioned substrate systems are encompassed by the
closed guiding rail. Thus, an image may be obtained
simultaneously on two substrates which are inside the
closed guiding rail, this substantially expanding the
consumer properties of the device and enhancing its
productivity.
According to an aspect of the present invention,
there is provided a large format ink-jet color printer
comprising:
at least one ink feeding mechanism that is movable
along a closed guiding rail for moving relative to a
substrate;
a printer control unit for sending instructions to
said ink feeding mechanism;
a substrate feeding system having a plurality of
feeding shafts and a plurality of tensioning shafts, said
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substrate feeding system for feeding the substrate
adjacent to a portion of said closed guiding rail;
wherein said plurality of feeding shafts are for
feeding the substrate into the color printer;
wherein said plurality of tensioning shafts are
positioned above and below said feeding shafts for
maintaining a desired amount of tension within the
substrate; and
wherein said plurality of feeding shafts and said
plurality of tensioning shafts are positioned so as to
maintain the substrate in a generally substantially
vertical plane.
According to another aspect of the present
invention, there is provided a large format ink-jet color
printer comprising:
a closed guiding rail adapted to surround a
substrate; and
at least one ink feeding mechanism that is movable
along said closed guiding rail relative to the substrate,
wherein said ink feeding mechanism receives electrical
power from said closed guiding rail.
According to a further aspect of the present
invention, there is provided a large format ink-jet color
printer comprising:
a closed guiding rail;
at least one ink feeding mechanism movable along
said closed guiding rail relative to said substrate,
wherein said ink feeding mechanism receives electrical
power from said guiding rail;
a printer control unit for sending instructions to
said ink feeding mechanism;
at least one receiver on said ink feeding mechanism;
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7b
and
at least one rapidly released catch adapted to
intermittently communicate with said receiver for
delivering air to said receiver.
According to another aspect of the present
invention, there is provided a large format ink-jet color
printer including:
a closed guiding rail;
at least one ink feeding mechanism movable along
said guiding rail relative to a substrate, wherein said
ink feeding mechanism receives electrical power from said
closed guiding rail;
a printer control unit for sending instructions to
said ink feeding mechanism; and
a controller on said ink feeding mechanism that
receives signals from said printer control unit and which
controls operation of said ink feeding mechanism.
According to a further aspect of the present
invention, there is provided a large format ink-jet color
printer comprising:
a closed guiding rail;
at least one ink feeding mechanism that is movable
along said closed guiding rail for moving relative to a
substrate;
a printer control unit for sending instructions to
said ink feeding mechanism;
a controller on said ink feeding mechanism, said
controller receives signals from said printer control
unit, said controller controls operation of said ink
feeding mechanism;
a hatched ruler on said closed guiding rail; and
at least one sensor on said ink feeding mechanism
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for reading said hatched ruler to determine an exact
position of said ink feeding mechanism, said sensor in
communication with said controller.
According to another aspect of the present
invention, there is provided a large format ink-jet color
printer comprising:
a closed guiding rail;
at least one ink feeding mechanism that is movable
along said closed guiding rail for moving relative to a
substrate;
a printer control unit for sending instructions to
said ink feeding mechanism;
at least one charging cartridge on said ink feeding
mechanism for receiving ink;
an electronic controller on said ink feeding
mechanism for receiving instructions from said printer
control unit;
at least one electrical valve on said charging
cartridge for receiving instructions from the electronic
controller; and
at least one rapidly-released catch adapted to
intermittently engage said charging cartridge for
recharging said charging cartridge, said rapidly-released
catch positioned proximate said closed guiding rail.
Brief Description of the Drawings
Figures l, 2, 3, 4, 5 illustrate the construction of
the device.
Fig. 1 shows a general perspective of a device with
one substrate feeding system;
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Fig. 2 shows tile mutual positioning cf the guiding
rail, busbars and substrate;
Fig. 3 shows the arrangement of the main units of
the ink feeding m.echan:ism;
Fig. 4 shows a p~:rspective of the rapidly-released
connections in the device;
Fig. 5 shows a general diagram of a davice with two
substrate feeding systems.
Hest Method of Carrying Out the Invention
The large format ink-j et colour printer ( Fig . 1 )
consists of a frame (1) , rollers (2) for feeding a
carrier, tension=~ng shafts (3) , a feeding shaft (4) ,
guiding rollers (5), pressing rollers (6), a receiving
shaft (7), a carriage (8), a guiding rail (9). The
tensioning shafts for the substrate are connected to
reducers (11) and reversible electric mcvtors (10) by
means of magnetic clutches ( 12 ) . Th~a shafts for
receiving and feeding the substrate are connected to
reversible drive elec:tz:ic motors via r~ducExs (not shown
in Fig. 1). The carriage (8) (Fig. 2) is placed on the
closed guiding rail (9) to which copper busbars (14) are
secured by means of supports (13) made of a
nonconductor. Electrical current is applied to the
busbars. By means of brushes (15), electric current is
applied to the power supply of the carriage (not shown
in the Fig.) and to other power consuming devices. The
ink feeding mechanism i.s shown in Fig. 3. A:~ electric
drive ( 16 ) f or ensuring movement of the carriage ( 8 ) , a
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receiver (17) for storing high pressure air for ensuring
operation of the jet elements, an assembly of heads (18)
with jet elements and charge cartridges (19) for storing
ink with level sensors (not shown in Fig. 3), an electric
drive control unit (20), an electronic controller (21)
for communication over a radio channel with a control
unit (not shown in the Fig.) and for ensuring operation
of all units of the carriage in the process of developing
images, an optical sensor (22) for positioning the
carriage relative to the substrate along a hatched ruler
(23) positioned on the guiding rail, a brush holder (24)
with brushes (15) for supplying power to the carriage are
disposed on the carriage (8). Diagrams showing the
positioning of rapidly released connections used to
recharge the carriages with air and ink are shown in Fig.
4. The air recharging system includes a pipe (25), a
supply coupling (26) with a movable tip (27) sitting on
the coupling with the possibility of rotating thereon, a
carrier arm (28) on which a rapidly-released catch (29)
for butt-joining and disengaging with a pipe (30) for
charging the carriage receiver is secured. In the initial
position the carrier arm (28) is held by a spring (31)
secured on the movable tip (27). The ink recharging
system is set up in a similar manner, except that ink
charging electric valves (33), connected to the charge
cartridges for the ink (19), are mounted on a carrier
(32). Rapidly released catches (34) are secured to a
lower (output) part of the electric valves (33) and
during the recharging are located opposite the necks of
the
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i0 .
charging cartridges (19) and the assembly o' heads with
cartridges for :ink (L8) , which are disposed or: the
carriage ( 8 ) _
The device o~~erates in the following manner.
In accordance with commands from the control unit
of the device, th.e feeding shaft (4~ moves the substrate
one working step eaual to the width of a line of the
image being produced, When the position of the
carriage (8) in the process of its uniform movement is
in the inoperative zon.e3 of the device ( Zones I and II,
See Fig_ 2), recharging of the carriages with air and
ink is Carried out, and also information, which should
be reproduced on the substrate, is transmitted over the
radio channel. When the controller (21), disposed on
the carriage, enters the working zone in the process of
- movement of the carriage, it effects autonomous control
of the process o:f putt:ing the information (in this case
by operation of the _jet elements) onto the substrate.
Upon exit from the working zone, the Control unit of
the device determine:; the condition of the de~crice,
effects control of tl2e operation of the air and ink
recharging syster:~s, effects movement of the substrates,
carries out additional servicing actions, czetermines the
wcrking capacity of t;he device, tests selrarate units,
brings out a message to the operate~r onto the
reproducing systs:m and effects the subseqU~nt operation
cycle. Gdhere there is one substrate present, the
device in accordance with the described algorithm may
effect the structuring of images from two sides, both
with the aid of one carriage and with the aid of two or
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more, and where 'there are two independent systems for
feeding substrates, the device has the possibility of
effecting the stew cturing of images on two substrates.
Tr.e general diagram of a device with two systems for
feeding a substrate and with two carriages is shown in
Fig. S.
I:zdustrial Applicability
The proposed technical solution makes it possible
to create large format: printers for producing printed
articles, ir. part:icular, in the production of outside
advertising obj ect~s .
Realization of this invention enhance3 the quality
of a produced art_~cle (i . a . the quality of an images and
increases the producti~,rity of printers by at least two
times.
