Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-04-20
2002-05-07
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06382766
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image forming apparatus such as an ink jet printer for forming an image by using ink, and more particularly, to an ink jetting nozzle maintenance apparatus of an image forming apparatus capable of preventing a blockage in an ink nozzle while a service station device, which is driven by the reciprocal movement of a carriage, is in the standby mode.
2. Description of the Related Art
Generally, when an ink cartridge is in the standby mode in an image forming apparatus, a jetting nozzle is exposed to the atmosphere and ink vaporizes, producing a sludge. Accordingly, contaminants such as dust block an inlet of the nozzle approximately of 20-40 &mgr;, deteriorating the print quality during a printing operation.
Accordingly, it has been suggested that the image forming apparatus employ a structure for preventing vaporization of the ink by sealing the nozzle surface of the ink cartridge in the standby mode. Such a structure includes a structure for wiping the nozzle surface with a wiper, and a structure for suctioning the nozzle surface with a pump.
Accordingly, as shown in
FIG. 1
, this suggested structure requires a separate pump for sucking in the ink, and a driving source for driving the pump.
Referring to
FIG. 1
, the conventional image forming apparatus includes a vaporization prevention cap
3
with a pump
5
which is connected to the vaporization prevention cap
3
through a tube
4
, for suctioning the nozzle surface of the ink cartridge
1
and thus for preventing inefficient ink jetting from occurring due to a blockage in the nozzle
2
by sludge and dust, and a motor
6
for serving the function of a driving source for driving the pump
5
.
Accordingly, the pump
5
is driven by the driving force from the motor
6
to suck in, and to waste the ink to an ink absorbing pad or a waste ink bin
7
. The conventional ink forming apparatus, however, has a disadvantage in view of an economical manner since it requires a separate driving source, complicating the structure and increasing the unit price. Further, since the ink is sucked and wasted in every printing operation, a considerable amount of ink is wasted when considering the actual ink amount used for the printing operation. As a result, a user has to go to great expense for the ink consumption.
Further, since the ink is sucked in only after the nozzle is sealed by the vaporization prevention cap
3
, the printing operation time is lengthened.
Due to the above-mentioned problems, image forming apparatuses rarely employ an ink pumping structure. resulting in the problems of nozzle blockage by the sludge and dust.
In other words, even though it is recognized that there is printing deterioration by the nozzle blockage due to the sludge and dust, the disadvantages such as increased cost and operation time result in most of the ink forming apparatus manufacturers doing nothing to correct the problem. The ink forming apparatus manufactures only perform a capping operation to seal the nozzle, wiping operation to scratch the nozzle, and spitting operation for a preliminary jetting, all by a service station apparatus (or so-called ‘home assembly’). The service station is driven by a carriage carrying the ink cartridge and reciprocating for the printing operation. Such a service station apparatus has already been disclosed and open to the public by the Korean Utility Model Publication No. 97-28155.
Although the above-mentioned service station apparatus has the advantage of low manufacturing cost, it has the disadvantage of nozzle blockage low printing quality, and reliability deterioration.
SUMMARY OF THE INVENTION
The present invention has been developed to overcome the above-mentioned problems and disadvantages of the prior art, and accordingly, it is an object of the present invention to provide an improved ink jetting nozzle maintenance apparatus capable of preventing nozzle blockage and performing an ink suctioning without delay.
The above object is accomplished by an image forming apparatus according to the present invention, including an ink cartridge holding ink for a printing operation, for jetting the ink toward an ink nozzle when receiving a printing command; a carriage for reciprocally moving on a paper in a horizontal direction while carrying an ink cartridge for a printing operation, the carriage for moving to a service area during the standby mode or a power-off period. A service station device driven by the reciprocal movement of the carriage a suction diaphragm formed in the cap for preventing the nozzle from drying by sucking out a certain amount of ink from the ink nozzle by using the cap; and a diaphragm lowering section driven by the reciprocal movement of the carriage for driving the service station device, for generating a pulling force for pulling the suction diaphragm to generate a negative pressure to suction the ink from the ink nozzle. The service station device having a cap for sealing the ink nozzle to prevent the drying of the ink nozzle of the ink cartridge; and a wiper for wiping the nozzle during a printing operation or during a paper feeding operation.
According to the features of the present invention, the ink droplets that are sucked out under the negative pressure remain at the ink nozzle prevent the nozzle from drying, and the ink-nozzle is wiped out by the wiper during the wiping operation for the printing operation.
Further, the cap, which includes the suction diaphragm, is formed of a rubber member having a certain elasticity for the extending of the suction diaphragm.
The diaphragm lowering section according to the present invention includes a suction rod for pulling the suction diaphragm; a rod guide connected to the suction rod for a lowering movement of the suction rod; and a cam groove formed on an inner wall of the housing for guiding upward and downward the movement of the rod guide.
It is another feature of the present invention that the cam groove is in a predetermined trajectory for a lowering operation which is to pull the suction diaphragm from the point when the cap seals the nozzle.
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Barlow John
Tran Ly T
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