Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2001-09-13
2003-06-17
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S029000, C347S023000, C347S032000, C347S033000
Reexamination Certificate
active
06578949
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording device, in which the ink jet recording device includes an ink jet recording head which is mounted on a carriage and ejects ink drops in accordance with print data, and a capping unit which seals and covers a nozzle forming surface of the recording head and receives a negative pressure from a suction pump to suck ink from the recording head and to discharge the ink outside. More particularly, the invention relates to an ink jet recording device in which a wiping member is mounted on the capping unit, and is brought into sliding contact with the nozzle forming surface of the recording head to wipe the nozzle forming surface, and a method for driving and controlling the ink jet recording device.
Generally, the ink jet recording device includes an ink jet recording head which receives ink from an ink cartridge, and a sheet feeding unit for moving a recording sheet of paper relative to the recording head. The recording device records an image pattern on the recording sheet in accordance with print data, while moving the recording head. A recording head, which is able to eject color inks of colors, such as black, yellow, cyan and magenta color inks, is mounted on a carriage. With use such a recording head, the ink jet recording device is capable of performing the full color printing as well as the text printing by varying a ratio of the color inks to be ejected.
To print by the recording head, ink is pressurized in a pressure generating chamber, and ejected through the nozzle opening of the head in the form of ink droplets onto the recording sheet. For this reason, the recording head has a possibility of causing a printing failure due to trouble regarding ink ejecting effect from the nozzle opening, such as an increase of ink viscosity or solidification of ink due to evaporation of solvent contained in the ink from the nozzle openings, the attaching of dust, and the entering of air bubbles into the head.
To cope with this, this type of ink jet recording device includes a capping unit for sealing and covering the nozzle forming surface of the recording head when the device is in a non-print mode. The capping unit functions as a lid for preventing the ink from drying at the nozzle openings of the recording head. When the nozzle opening or openings are clogged, the capping unit also functions to remove the clogging in a manner that it sucks the ink from the nozzle openings by the utilization of a negative pressure from the suction pump.
The forcible ink sucking operation for removing the clogging is called a cleaning operation. The cleaning operation is performed when the recording device have been left not used for a long time and starts again its operation, when the user recognizes a printing failure and operates a cleaning switch, and in other situations. In the cleaning operation, a negative pressure is applied from the suction pump to the nozzle forming surface of the recording head, and the ink is sucked therefrom and discharged into the capping unit. Then, the nozzle forming surface is wiped out with a wiping member made of rubber or the like.
In the related recording device, the capping unit is mounted on a drive unit which is capable of crawling on the nozzle forming surface of the recording head by the utilization of a drive force of the carriage when it moves to the home position. The wiping member is mounted on a horizontal drive unit which moves to and from a movement region of the recording head within which the recording head is moved with the movement of the carriage. With the cleaning operation, a cleaning sequence is executed in which the wiping member wipes out the nozzle forming surface of the recording head while rubbing lightly the surface.
Thus, in the related recording device, separate drive units are used; the vertical drive unit for vertically driving the capping unit and the horizontal drive units for driving the recording head within the movement region in the horizontal direction. This fact entails the increase of device size and cost to manufacture.
Many recording devices of this type are designed such that the power generated by a sheet feeding motor, which feeds a recording sheet in a direction orthogonal to the moving direction of the carriage, is utilized for the drive force necessary for the horizontal drive unit for driving the wiping member for its forward and backward movement, and the drive force necessary for the suction pump.
To this end, a friction clutch is incorporated into the drive unit for driving the wiping member. In an initial stage of the rotation of the sheet feeding motor to one direction, the wiping member is advanced to the head movement region and is put to a set state. In an initial stage of the rotation of the motor to the other direction, the wiping member is retracted from the head movement region and is put to a reset state through the friction clutch.
Accordingly, if, as the result of the cleaning operation, the friction clutch is smeared with waste ink sucked from the recording head and waste ink wiped from the nozzle forming surface of the recording head, the normal driving of the wiping member is hindered. Further, if the gear, e.g., a drive gear, for transmitting a drive force to the friction clutch, is smeared with the waste ink, solidified waste ink will excessively increase the load of the sheet feeding motor. This will create more serious problems.
An ink jet recording device with a head cleaning mechanism is proposed in JP-A-10-193629. This head cleaning mechanism is operable without the drive unit for moving the wiping member to and from the recording head in the horizontal direction. In the mechanism, a slider is located adjacent to the home position of the recording head. The cap member and the wiping member are supported on the slider. When the recording head moves to the home position, the slider is moved toward the nozzle forming surface of the recording head in connection with the head movement, and the nozzle forming surface of the recording head is sealed and capped with the cap member.
When the recording head is moved apart from the home position, the slider is moved in such a direction as to separate the slider from the nozzle openings of the head, and the sealing of the nozzle forming surface with the cap member is removed. During the slider moves apart from the nozzle openings, the slider is locked to halt its movement. With the subsequent movement of the recording head, the nozzle forming surface of the recording head is wiped out with the cap member.
In the disclosed technique, when the recording head is moved from the home position to the head movement region, the slider is locked and halts its movement. Accordingly, the nozzle forming surface of the recording head is inevitably wiped out with the wiping member. Therefore, also when a flushing operation for idle ink ejection is performed by applying a drive signal not related to the printing to the recording head, the nozzle forming surface is wiped with the wiping member.
During the wiping operation, the solidified ink sticking to the wiping member comes in sliding contact with the nozzle forming surface. As a result, there is the possibility that the solidified ink damages the nozzle forming surface, and the nozzle openings are clogged with the solidified ink. Further, there is possibility that the wiping operation destroys the ink meniscus at the nozzle openings after the ink meniscus have been restored to good condition through the flushing operation.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an ink jet recording device and a method for driving and controlling the same, which solve the problem of the damaging of the nozzle forming surface by the wiping operation and the problem of the hindering of the normal ink ejecting operation by the wiping operation in a manner that the wiping operation by the wiping member is appropriately selected in its execution by the utilization of a mechanical arrangement in which the wiping
Akase Takashi
Hayakawa Hitoshi
Iizuka Kojiro
Okumura Hideki
Ota Mitsugu
Barlow John
Liang Leonard
Sughrue & Mion, PLLC
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