Cleaning and liquid contact with solids – Processes – Hollow work – internal surface treatment
Reexamination Certificate
1998-12-14
2001-08-14
Gulakowski, Randy (Department: 1746)
Cleaning and liquid contact with solids
Processes
Hollow work, internal surface treatment
C118S302000, C347S028000, C347S036000, C347S073000, C347S076000
Reexamination Certificate
active
06273103
ABSTRACT:
TECHNICAL FIELD
The present invention relates to continuous ink-jet printing and, more particularly, to the cleaning of printhead orifices and charging leads.
BACKGROUND ART
Continuous ink jet printheads utilize a series of orifices separated from charging leads by a small gap. Fluid is forced through the orifice while the printhead is in operation. Upon shutdown, the ink floods the leads and the area around the orifices. This fluid then dries, leaving behind non-volatile components in the form of solids or gels. Depending on the ink chemistry, this ink may polymerize as it dries, rendering it insoluble. Upon subsequent startups, the failure to remove or redissolve all of this material in the orifice and gap creates disturbances in the shape or direction of the emerging jet. Heavy deposits may block the orifice altogether. Deposits left on the charging leads may leave films which impair the proper charging of the drops as they form, causing insufficient deflection of the drop.
Current ink jet systems consist of a fluid module with a removable printhead. In the course of operation it may become necessary to move a printhead from one system to another. Ink residue remaining in the printhead from the previous system may contaminate the second system if the ink color or chemistry is incompatible.
This problem has been addressed in the prior art. For example, U.S. Pat. No. 5,706,039 distributes a cleaning fluid externally, in the plane of the orifices, not through them. This requires the use of a two layer construction, or forming internal passages within the orifice plate. The vacuum used to remove cleaning fluid in the vicinity of the orifice may also carry external debris into the orifices. U.S. Pat. Nos. 5,570,117 and 5,555,461 utilize wipers to remove ink from the orifices, with no additional cleaning fluid used. U.S. Pat. No. 5,557,307 uses a cleaning thread to wipe the orifices. Ink is adsorbed onto the thread, removing it before it dries.
Unfortunately, mechanical devices such as wipers and thread need replacement or maintenance from time to time and may serve to push particles into the orifices. It is seen, then, that there is a need for a system and/or method for cleaning a printhead which will avoid the problems associated with the prior art.
SUMMARY OF THE INVENTION
This need is met by the printhead flush and cleaning system and method according to the present invention. In accordance with the present invention, there is provided a means for cleaning a printhead which avoids the formation of deposits. The present invention removes dried deposits by providing a cleaning fluid with a low surface tension to dissolve or flush material away from the orifices, all without mechanical contact which could abrade or damage the orifices.
In accordance with one aspect of the present invention, a system and method are provided for cleaning the printhead of a continuous ink jet printing system. A cleaning fluid is introduced and used to flush ink residues and debris from the interior of the drop generator, the exterior of the orifice plate, the charge plate face and the catcher face. This system and method removes dried ink residues and other debris and deposits by providing a cleaning fluid with a low surface tension to dissolve or flush away the unwanted material from the orifices.
Other objects and advantage of the present invention will be apparent from the following description and the appended claims.
REFERENCES:
patent: 4296418 (1981-10-01), Yamazaki et al.
patent: 4528996 (1985-07-01), Jones
patent: 4542389 (1985-09-01), Allen
patent: 4623897 (1986-11-01), Brown et al.
patent: 4928114 (1990-05-01), Fagerquist et al.
Blum John N.
Enz Richard T.
Loyd John C.
Lyman Dan C.
Simon Robert J.
Gulakowski Randy
Haushalter Barbara Joan
Scitex Digital Printing, Inc.
Wilkins Yolanda
LandOfFree
Printhead flush and cleaning system and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Printhead flush and cleaning system and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Printhead flush and cleaning system and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2544619