Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-04-02
2001-07-10
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S023000, C347S005000
Reexamination Certificate
active
06257696
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet recorder, such as an ink jet printer having a purging apparatus for sucking ink from a ink jet head and a purging method therefor.
2. Description of Related Art
Ink jet printers are known generally as ink jet recorders for recording on recording media, such as sheets of paper, by ejecting ink onto them.
FIG. 9
of the accompanying drawings shows part of a conventional ink jet printer, which includes a recording head unit P
3
having a recording head P
2
. The head P
2
has four ejection nozzles P
4
, each of which has ejection holes (not shown) opening in its front surface P
5
. The ejection nozzles eject different colored inks including black, yellow, cyan and magenta, respectively. Four ink cartridges P
1
containing the respective colored inks are mounted replaceably on the head unit P
3
, and each connected to the corresponding nozzle P
4
. After each cartridge P
1
is replaced with a new one, ink is supplied from the new cartridge to the head P
2
, and can be ejected from the associated nozzle P
4
.
The printer is provided with a purging device having a cap P
6
and a suction pump (not shown) in order to purge the nozzles P
4
. The purging may be started manually by the user operating a switch on the printer, or automatically if a predetermined condition is satisfied. The purging is performed to prevent the defective ejection of ink which may be caused if the ink in or on the recording head P
2
dries, or if air bubbles are produced in the ink, or if droplets of ink stick to the nozzle surfaces P
5
. Specifically, the purging of each nozzle P
4
involves covering its nozzle surface P
5
with a suction cap P
6
, and then developing negative pressure in the cap P
6
by means of a suction pump (not shown), in order to suck ink from the head P
2
through the cap P
6
and discharge the sucked ink outside.
Conventionally, when the purging operation is performed for all four ejection nozzles P
4
successively, the nozzle for ejecting black ink is purged last. Namely, the purging operation has been done in order of lighter color inks. However, when the purging operation is performed in order of lighter color inks, there is a problem that some color inks tend to dry during the operation, because only one nozzle can be capped by the cap p
6
at a time.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an ink jet recorder which can prevent the ejection nozzles from drying during the purging operation.
According to a first aspect the invention, an ink jet recorder comprising:
a recording head having a plurality of ejection surfaces each containing a nozzle for ejecting a different ink;
a purging device for purging the nozzle of one ejection surface at a time within the plurality of ejection nozzles; and
a controller for controlling the purging device in such a manner that a nozzle having an ink with higher dry resistance is purged before a nozzle having an ink with lower dry resistance is provided.
Inks used for the ink jet recorder are different from each other in a tendency of drying depending on component and composition of wetting agent, dye and like included therein. Accordingly, in the present invention, the purging operation for the plurality of ejection nozzles are performed in such manner that the nozzle for ejecting the ink with higher dry resistance is purged before the other nozzles ejecting the inks with lower dry resistance. Namely, as the ink has lower dry resistance, the corresponding nozzle to the ink is purged later. Therefore, each nozzle can be prevent from drying during the purging operation and an excellent recording can be maintained, especially in an initial recording stage subsequent to the purging operation.
In the recorder according to the invention, the purging device may comprise a suction cap to cover the one ejection surface at a time and a suction pump to suck the ink in the recording head though the nozzle and the suction cap, and the recorder may further comprise a moving device for moving the suction cap relative to the nozzle. The inks may be different each other in terms of color. As different inks in color have different dry resistance characteristics, a nozzle for ejecting a colored ink with higher dry resistant is purged first. The different inks may be magenta, cyan, yellow and black inks. In this case, it is preferable that the nozzle ejecting black ink is purged last because black ink generally tends to dry first among the colored inks. However, as described above, the dry resistance characteristic of ink can be determined by the components included therein and the composition thereof rather than the color.
The ink jet recorder according to the invention may further comprise a memory storing information on dry resistance characteristics of the different inks. In the ink jet recorder, the ejection surfaces may be arranged so as to be lined up from one end of the recording head according to the dry resistance characteristics of inks ejected from the ejection surfaces. Thereby, movement of the recording head relative to the purging device can be minimum and time for the purging operation can be shortened.
According to a second aspect of the invention, a purging method for an ink jet recorder comprising a recording head having a plurality nozzles for ejecting a plurality of colored inks and a purging device capable of purging one of nozzles at time, characterized in that a nozzle having an ink with higher dry resistance is purged before a nozzle having an ink with lower dry resistance is provided. Thereby, the nozzles of a recording head can be prevented from drying to ensure high recording quality.
REFERENCES:
patent: 5726692 (1998-03-01), Yamaguchi et al.
Brother Kogyo Kabushiki Kaisha
Hsieh Shih-Wen
Le N.
Oliff & Berridg,e PLC
LandOfFree
Ink jet recorder does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink jet recorder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet recorder will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2444928