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HP Forum Archive 08

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HP Thermal Printers
Message #1 Posted by Juergen Rodenkirchen on 6 June 2002, 3:52 a.m.

I have several HP Thermal Printers and I usually keep the paper in place even if I do not work with the machine(s) in a long time. Now I wondered if this could damage the pinter (head) in any way. Can someone answer my question? Any advice is appreciated. Thanks for your time!

      
Re: HP Thermal Printers
Message #2 Posted by David Smith on 6 June 2002, 5:21 p.m.,
in response to message #1 by Juergen Rodenkirchen

Since most non-archival papers are rather acidic and the thermal paper contains chemicals, there is a possibility that over time it could corrode the rather small and delicate print head resistors.

I have seen several machines that sat unused for many years. After cleaning them up and installing new paper, they print just fine for a few lines and then a dot or two in the print head opens up. I have attributed this to corrosion of the resistors in the print head. I don't know if the paper had anything to do with it or not, but it probably did not help.

            
Re: HP Thermal Printers
Message #3 Posted by Tony Duell (UK) on 6 June 2002, 7:54 p.m.,
in response to message #2 by David Smith

Are you sure it's the resistor that opens? I've had several printheads that get clogged with dirt, and I've had the flexiprint cable go open-circuit. I've had the printhead physically cracked. But I've never had a printhead heater resistor go open-circuit. Have you actually checked the resistance of the heaters at the printhead end of the flexiprint (i.e. between the traces on the ceramic substrate)?

                  
Re: HP Thermal Printers
Message #4 Posted by David Smith on 7 June 2002, 5:04 p.m.,
in response to message #3 by Tony Duell (UK)

Yes, I even checked heads under a microscope and they are definitely bad. I have two '19C's, 2 97's, and three or four HP41 printers missing dots in their heads. I have not had any problems with the flex cables opening up.

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