The fan stops running when my Designjet 30 is turned off. It appears the plastic bladder inside the printhead is the suspect in several cases of premature failures. A tiny crack is developed in the bladder which causes it to be unable to expand enough to open a valve that allows ink to enter the printhead to replenish the used up ink.
Does operating temperature have anything to do with life expectancy of this bladder? I don't really know, but I do feel it may be a good thing to wait for the heads to warm up sufficiently after a period of the machine being turned off. I think plastic is more pliable when warm. This bladder expands when vacuum inside the head develops due to ink being jetted out. The expansion overcomes a spring to open the aformentioned valve. There must be a perfect balance here, if the valve is opened too easily, the head will be flooded, if there is not enough vacuum to cause the expansion, ink will not be replenished. The lack of vacuum may be caused by a certain number of cells (jets) that failed electronically. I believe this design is the reason why the printer requires recalibration so regularly, and the cause of so many premature printhead failures. So far it costs me more to replace my HP printheads than my comparable Epson with a permanent head. --nick --- In [email protected], Morrie Portnoff <[EMAIL PROTECTED]> wrote: > > Yep I always thought there was a heater. But in either case > heater or power supply the heads are warm. The one time I > unplugged the machine for an extended period of time the > yellow print head went on me. Coincidence??? ------------------------------------ Website: http://groups.yahoo.com/group/HPDesignJet_Printers Post message: [email protected] Subscribe: [EMAIL PROTECTED] Unsubscribe: [EMAIL PROTECTED] List owner: [EMAIL PROTECTED] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/HPDesignJet_Printers/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/HPDesignJet_Printers/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
