Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-07-10
2002-01-22
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S010000
Reexamination Certificate
active
06340217
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet recording apparatus and a recovery method thereof, and more particularly to an ink jet recording apparatus for performing the color recording and a recovery method thereof.
2. Related Background Art
The ink jet recording apparatuses are typically provided with a variety of mechanisms for maintaining the ink discharge condition excellent by preventing the viscosity of ink from increasing due to evaporation of water content of the ink at or around discharge ports where the ink makes contact with the air, or removing viscous ink or bubbles produced.
Therefore, this type of ink jet recording apparatus is provided with a capping mechanism for preventing evaporation of water content of the ink from the discharge ports by sealably enclosing (or capping) the face where the discharge ports of the recording head are provided while the recording is not performed to discharge ink droplets.
Also, in order to effect the stabler ink discharge, a so-called “predischarge” is conducted to renew the ink in the discharge ports not particularly involving recording by discharging the ink from all the discharge ports or the desired discharge ports of the recording head at a predetermined location periodically, such as during the recording operation, or the ink suction or ink pressurization is performed to expel the thickened ink or produced bubbles by sucking the ink on and within the discharge ports at the start of recording or at every desired time interval.
FIG. 36
is a perspective view illustrating the construction of a main portion of a conventional ink jet recording apparatus.
In
FIG. 36
,
921
is an ink jet recording cartridge (hereinafter simply referred to as a cartridge) integrally comprising a recording head having a nozzle portion for jetting the ink mounted on a carriage
922
and an ink supply unit having an ink tank for storing the ink and a supply passageway.
This cartridge
921
is detachably secured to the carriage
922
to use either a cartridge dedicated for Bk (black) ink recording or a cartridge dedicated for color ink recording by replacement. The carriage
922
and the cartridge
921
is electrically connected to a contact pad, not shown.
923
is an electrical substrate for controlling the ink discharge from the cartridge
921
, and
924
is a flexible cable for connecting the electrical substrate
923
to the carriage
922
.
925
is a sheet feeding motor, in which the recording sheet P can be conveyed in a direction of the arrow f as shown by a pair of rollers
926
by the driving of this sheet feeding motor
925
.
927
is a roller for regulating the recording sheet P flat in cooperation with the rollers
926
and forming the recording plane for the recording cartridge
921
.
928
is a carriage driving belt connected to the carriage
922
,
929
is a motor for driving that belt in a direction of S as shown, and
930
is a pair of guide rails for the carriage
922
. The carriage
922
is moved along the guide rails
930
in the direction of S as shown by the driving of the motor
929
to effect the recording on the recording plane.
The cartridge
921
is mounted on the carriage
922
, which is driven along the recording sheet P in the direction of S as shown in
FIG. 36
by the motor
929
. The recording sheet P is conveyed in a direction of the arrow f as shown via the roller
927
by the driving of the sheet feeding motor
925
. Thereby, the two-dimensional scanning by the recording head
921
can be effected. Then, the recording head
921
can perform the recording on the recording sheet P by jetting ink droplets under control of a control unit.
931
is a recovery device, opposed to the recording cartridge
921
, for effecting the recovery operation of the recording cartridge
921
at a home position H of the recording cartridge
921
. The recovery device
931
is comprised of a predischarge receiving portion
1311
for capturing ink droplets discharged at the predischarge as previously described to lead them to an ink reservoir (not shown), a wiping blade
1312
for wiping out ink droplets or foreign matter such as paper powder adhering to the discharge port face of recording head, and capping means
1313
having a cap for enclosing the discharge port face of recording head when the recording operation is not performed, or in the suction recovery operation.
The wiping blade
1312
and capping means
1313
are disposed movable back and forth with respect to the cartridge
921
, and is capable of wiping or capping the discharge port face at desired timings. Also, capping means is connected to a suction pump (not shown) via a tube to be able to produce a negative pressure within the cap at desired timings.
A flowchart exemplifying a sequence of suction recovery operation in the recovery device as above constructed is shown in FIG.
37
. If the suction recovery operation is instructed, the carriage
922
is moved to a home position (HP) (step S
701
), and the capping means covers the discharge port face to complete the capping (step S
702
). Next, the suction pump is activated to produce a negative pressure within the cap to suck the ink from the discharge ports to effect the suction operation, until the suction operation is completed by stopping the activation of suction pump at a predetermined timing (step S
703
).
Then, the cap in the capping means is separated away from the discharge port face, so that the interior of the cap is in communication with the atmosphere (step S
704
). Then, the suction pump is activated again to remove the ink within the pump, the tube and the cap (step S
705
). Then, the wiping blade advance to the discharge port face (step S
706
), and further the carriage
22
is moved in a direction toward the blade to allow the wiping blade to rub against the discharge port face to effect wiping to remove the ink adhering to the discharge port face (step S
707
).
Further, the carriage
922
continues to be moved in the same direction, and executes the predischarge upon reaching a position at which the discharge ports are opposed to the predischarge receiving portion, to expel the unnecessary ink or small bubbles out of the nozzles (step S
708
). By the suction recovery comprising such a series or a repetition of operations, the filling of the ink into the discharge ports, the removal of bubbles or unnecessary ink out of the ink flow passages, or the removal of foreign matter on the discharge port face, can be effectively made.
However, in recent years, the recording heads allows the discharge ports and the liquid channels in communication with them to be constructed quite finely and at high density, for which the prior suction recovery methods as heretofore used have become less effective in some cases.
FIGS. 38A and 38B
are schematic views illustrating how the ink within liquid passageway is parted into a plurality of sections, as an example of the above cases.
FIG. 38A
is a typical view showing the constitution of cartridge
921
, and
FIG. 38B
is a cross-sectional view of cartridge
921
taken along a plane V including an array of discharge ports, representing an ink filled state.
In
FIG. 38A
,
811
are nozzles each of which at the end is an ink discharge port, and internally provided with driving means for discharging each of the inks.
812
is a liquid chamber commonly provided to each nozzle (referred to as a common liquid chamber), and
813
is an ink flow passageway for connecting an absorbing member
814
containing the ink to the common liquid chamber
812
.
In
FIG. 38B
, the solid painted portion indicates the ink filled state, wherein the ink is parted into four sections
813
a,
813
b,
813
c,
813
d
in the figure.
With such a head in the ink filled state, it is impossible to continue the printing, for which the suction recovery is needed.
FIG. 39
is a typical view showing the state of a head cartridge at the time of starting the suction.
1313
is capping means as previously described to produce a negative pressure P
0
within t
Arai Atsushi
Ebisawa Isao
Kanda Hidehiko
Yaegashi Hisao
Hsieh Shih-wen
Le N.
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