Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2002-03-20
2004-04-06
Hsieh, Shih-Wen (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S029000, C347S030000, C347S092000
Reexamination Certificate
active
06715855
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet recording device and a bubble removing method.
2. Description of the Related Art
In an ink jet recording head mounted on the carriage of an ink jet recording device, a measure to image quality deficiency due to a bubble (ink droplet non-discharge) has been taken.
Image quality deficiency due to a bubble is caused in such a manner that a bubble larger than the cross-sectional size of an individual channel is attached to a portion for opening the edge of the individual channel in a common liquid chamber to clog the opening portion, resulting in inhibition of ink supply.
To remove the bubble, typically, an ink discharge opening is capped for negative-pressure suction so as to be discharged outside together with ink in the recording head.
Other than the ink discharge opening for printing, also typical is a method in which several to several tens of large dummy nozzles are provided to suction ink from the dummy nozzles, thereby suctioning and removing a bubble in the recording head.
To recover image quality deficiency due to a bubble produced in the recording head with respect to the related art, various proposals have been made. Some examples will be described hereinbelow.
Japanese Published Unexamined Patent Application No. Sho 63-224958 (hereinafter, referred to as related art
1
) discloses that an elastic cap is pressed against an ink discharge opening to increase the internal pressure which is released into the atmosphere, and then, a suction recovery operation is performed.
Japanese Published Unexamined Patent Application No. Hei 2-78567 (hereinafter, referred to as related art
2
) disclose that a pressurizing heater is provided aside from a recording heater, and the pressurizing heater can provide a dummy jet to reduce the ink consumption for discharge recovery, thereby shortening the recovering time.
Japanese Published Unexamined Patent Application No. Hei 4-219253 (hereinafter, referred to as a related art
3
) discloses that a heater of an ink discharge opening adjacent to the ink discharge opening for discharge recovery is driven to discharge a bubble.
Japanese Published Unexamined Patent Application No. Hei 4-363253 (hereinafter, referred to as related art
4
) discloses that in a recovery mode, an energy 1.48 times or more larger than a minimum energy which can form a bubble to perform ink discharge is supplied to perform preliminary discharge 1000 times or more.
Japanese Published Unexamined Patent Application No. Hei 5-155035 (hereinafter, referred to as related art
5
) discloses that when a bubble is small and is diffused into ink within a predetermined time, printing is stopped corresponding to the diffusion time in ink.
Japanese Published Unexamined Patent Application No. Hei 7-195711 (hereinafter, referred to as related art
6
) discloses that a bubble producing heater is provided aside from a recording heater, wherein a produced bubble and remaining bubbles are integrated to be suctioned reliably.
Japanese Published Unexamined Patent Application No. Hei 8-58095 (hereinafter, referred to as related art
7
) discloses that an ink channel section between a recording head and an ink reservoir part is of a shape in which at least 90% of the entire length defines a circle having a diameter below 1 mm as a circumcircle so as to increase the flow velocity of the ink channel, thereby reliably removing a bubble when ink is suctioned.
Japanese Published Unexamined Patent Application No. Hei 8-169124 (hereinafter, referred to as related art
8
) discloses that a discharge signal having a frequency higher than that of a discharge signal at recording is added at a recover operation, and then, suction is performed for recovery.
The following measures have been taken to the ink jet recording device in order to prevent nozzle clogging due to printing stop or permit recovery from clogging.
Japanese Published Unexamined Patent Application No. Sho 62-211150 (hereinafter, referred to as related art
9
) discloses that pressurizing ink is supplied to an ink supply passage to flow the ink from a nozzle, thereby eliminating ink clogging and removing a bubble.
Japanese Published Unexamined Patent Application No. Sho 63-53047 (hereinafter, referred to as related art
10
) discloses that a nozzle and a reciprocating pump are communicated to each other to perform a suction operation, thereby suctioning ink from the nozzle for a recovery operation.
Japanese Published Unexamined Patent Application No. Hei 5-229138 (hereinafter, referred to as related art
11
) discloses an ink jet recording device using conductive ink, wherein when ink non-discharge is detected, the voltage of an ink discharge power source is increased to recover ink non-discharge.
Japanese Published Unexamined Patent Application No. Hei 7-186402 (hereinafter, referred to as related art
12
) discloses that a nozzle part is brought into contact with a cap to be driven in a closed state so as to permit head temperature rise and recovery without wasting ink.
Japanese Published Unexamined Patent Application No. 2001-38925 (hereinafter, referred to as related art
13
) discloses that a capping unit has a suction opening and a suction pump disposed in at least two spaced positions, allowing a closed valve to be in an open state while the upstream side valve of a recording head is opened and driving the suction pump selectively or simultaneously.
The related art for removing a bubble by negative-pressure suction including the related arts
1
and
6
to
8
has the following disadvantages.
Since the suction unit is necessary, the mechanism is complicated and the waste ink amount is increased.
To realize highly fine image quality such as a picture, a recording head for discharging a small amount of ink droplet is necessary. In such a recording head, the section of the ink discharge opening and the individual channel is a circle having a diameter of about several &mgr;m to several tens of &mgr;m or a rectangle having one side of about several &mgr;m to several tens of &mgr;m.
The cross-sectional area of the individual channel is reduced to increase the channel resistance. Unless the negative-pressure suction force is increased considerably, an ink flow velocity enough to suction and remove a bubble from the recording head cannot be obtained.
The related art for removing a bubble by the dummy nozzles has the following disadvantages.
The recording head is larger since the ink discharge opening not contributing to printing is formed. When the negative pressure in the recording head is high, a bubble is suctioned into the common liquid chamber from the ink discharge opening for the dummy nozzle with a large cross-sectional area.
The construction of the related art
2
has the disadvantage that the pressurizing heater is necessary so that the device is complicated.
In the construction of the related art
3
, it is difficult to detect the ink discharge opening (individual channel) for discharge recovery, and more bubbles may be suctioned into the head from the ink discharge opening recovered by ink discharge from the adjacent ink discharge opening.
In the construction of the related art
4
, since the heater is driven by an excessive energy as compared with ink discharge for normal printing, there arises the problem in the reliability of the electric circuit and the life of the heater.
In the construction of the related art
5
, since printing is stopped together with bubble production, the printing processing ability is lowered.
The related art for preventing clogging has the following disadvantages.
In the construction of the related art
9
, since the pressurizing unit is necessary, the device is larger and the device cost is increased. Ink can be leaked from the ink supply passage connection part by pressure at pressurization.
In the construction of the related art
10
, a pump and solenoid are necessary for a suction operation. The device is larger and the device cost is increased.
In the construction of the related art
11
, the pow
Fujii Masahiko
Ikeda Kenji
Oda Kazuyuki
Takeuchi Takayuki
Yoneyama Takeshi
Fuji 'Xerox Co., Ltd.
Hsieh Shih-Wen
Oliff & Berridg,e PLC
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