Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-12-27
2003-09-16
Hsieh, Shih-wen (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S023000, C347S029000
Reexamination Certificate
active
06619783
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a flushing position controller incorporated in an inkjet recording apparatus and a flushing method used for the same. More particularly, the present invention relates to an ink-jet recording apparatus comprising an ink-jet recording head which is mounted on a carriage so as to travel in the widthwise direction of recording paper and which forms an image on a recording medium by ejecting jets of ink droplets via nozzle orifices, and a flushing region provided on the path along which the recording head travels for receiving ink droplets to be jetted when a flushing drive signal is supplied to the recording head; a flushing method for use with such an ink-jet recording apparatus; and a flushing position controller for use with the ink-jet recording apparatus.
Ink-jet recording apparatus can print small dots at a comparatively low noise level at high density, and hence they have recently been used in many printing applications, including color printing.
Such an ink-jet recording apparatus comprises an ink-jet recording head which receives ink supplied from an ink cartridge, and a paper feeder for feeding recording paper relative to the recording head. Text or an image is recorded on the recording paper by causing the recording head to eject ink droplets toward the recording paper while the recording head travels together with a carriage in the widthwise direction of the recording paper.
For example, a black recording head for ejecting black ink and a color recording head capable of ejecting various colors of ink, such as yellow, cyan, and magenta, are mounted on a single recording head. The ink-jet recording apparatus enables full-color printing through use of black ink and other colors of ink, as well as printing of text, by means of changing the proportions of color inks to be ejected.
Such an ink-jet recording head performs a printing operation by ejecting ink, which is pressurized in a pressure generating chamber, in the form of ink droplets by way of nozzles. The ink-jet recording head suffers problems such as printing failures, which are caused by an increase in the viscosity of ink due to evaporation of a solvent by way of nozzle orifices, solidification of ink, adhesion of dirt or dust to the nozzles, or mixing of air bubbles into ink.
In order to prevent the printing failures, the ink-jet recording apparatus is equipped with a capping member for sealing the nozzle orifices of the recording head while the recording apparatus is in a non-printing mode, and a cleaning device for cleaning a nozzle plate, as required.
The capping member acts as a cap for preventing ink from being dried by way of the nozzle orifices while the recording apparatus is in a non-printing mode. Further, in the event that the nozzle orifices become clogged, the capping member seals the nozzle plate and eliminates clogging in the nozzle orifices caused by solidification of ink or an ink ejecting failure caused by mixing of air bubbles into the ink flow channel, by suctioning ink by way of the nozzle orifices and by means of negative pressure imparted by a suction pump.
Forced discharging operation, which is performed in order to eliminate clogging in the recording head or air bubbles mixed into the ink flow channel, is usually called cleaning operation. The cleaning operation is performed when a printing operation is resumed after the recording apparatus has remained in an idle mode for a long period of time or when the user actuates a cleaning switch for eliminating degradation in the quality of a recorded image. The cleaning operation involves removal of ink droplets from the recording head by means of negative pressure applied through suction, and wiping of the surface of the recording head by means of a wiping blade formed from rubber or an elastic plate.
The capping member also has a capability of ejecting ink droplets by application to the recording head of a drive signal that is irrelevant to printing. This function is usually called flushing operation. The flushing operation is performed at predetermined cycles for the purposes of: recovering meniscuses, which are formed irregularly in the vicinity of nozzle orifices of the recording head as a result of wiping action of the wiping blade during the cleaning operation; discharging mixed ink which has flowed back from the nozzles as a result of wiping operation; and preventing clogging in the nozzle orifices from which a small amount of ink droplets is ejected during a printing operation, which would otherwise be caused by an increase in the viscosity of ink.
The schematic configuration of an ink-jet recording apparatus capable of effecting a flushing operation and a cleaning operation such as those mentioned previously will now be described by reference to FIG.
23
.
In
FIG. 23
, reference numeral
1
designates a carriage. The carriage
1
is configured so as to travel back and forth along a carriage shaft
4
which is horizontally supported by side frames
2
and
3
, by way of movement of a timing belt driven by an unillustrated carriage motor.
An ink-jet recording head
5
is mounted on the carriage
1
so as to face downward, and a black ink cartridge
6
for supplying black ink to the recording head
5
and a color ink cartridge
7
are removably mounted on the top of the carriage
1
.
A paper guide member
8
is situated below the recording head
5
and extends in the same direction as that in which the recording head
5
scans, and recording paper
9
serving as a recording medium is placed on the paper guide member
8
. The recording paper
9
is fed in the direction orthogonal to the scanning direction of the recording head
5
, by means of an unillustrated paper feeder.
Reference numeral
10
designates a capping member disposed in a non-print region (i.e., the home position). When the recording head
5
has moved to a position immediately above the non-print region, the capping member
10
can seal a nozzle plate serving as a nozzle forming surface of the recording head
5
.
A suction pump
11
is disposed below the capping member
10
so as to impart negative pressure to the interior space of the capping member
10
.
The capping member
10
acts as a cap for preventing drying of the nozzle orifices of the recording head
5
while the inkjet recording apparatus is in a non-print mode, and as a member for sucking ink by imparting negative pressure supplied from the suction pump
11
to the recording head
5
.
A wiping member
12
formed from rubber or an elastic plate is provided in the vicinity of the capping member
10
. When the carriage
1
travels back and forth toward the capping member
10
, the wiping member
12
wipes a nozzle forming surface of the recording head
5
.
A flushing region
13
A is provided in another non-print region which is located opposite the non-print region where the capping member
10
is provided, with a center print region located therebetween.
The flushing region
13
A is defined by an aperture
13
a
formed in the paper guide member
8
.
An ink-absorbing member
14
is disposed behind the aperture
13
a
(or on the inner bottom of the recording apparatus) and doubles as a member for absorbing and retaining the ink discharged by the suction pump
11
from the interior space of the capping member
10
. The ink-absorbing member
14
is housed in an ink-absorbing material housing case disposed along the paper guide member
8
; i.e., a waste-ink tank
15
.
In the recording apparatus, nozzles are periodically flushed in order to prevent ejecting failures, which would otherwise be caused by an increase in the viscosity of ink remaining in the nozzles which are not used during the printing operation.
Particularly, a recent large-scale model of the ink-jet recording apparatus performs flushing of ink at an average rate of several tens of droplets per nozzle every several seconds.
After a cleaning operation, at the beginning of a printing operation, or periodically during a printing operation, thousands of droplets or even tens of thousands of dropl
Fukasawa Shigenori
Hara Kazuhiko
Kanaya Munehide
Kobayashi Atsushi
Suzuki Kazunaga
Hsieh Shih-wen
Logan Smalls
LandOfFree
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