HP InkJet question regarding speed of system
Steve Rennells
Posts: 40
I have an idea for a project using the HP InkJet kit, but I'm not sure if the system is fast enough. The material would be traveling past the printhead at 155 inches per second, each piece separated by approximately 3 inches. Printing would be triggered via a photocell. Anybody have an idea if the serial board can keep up with the material traveling that fast? Or if the bs2/sx/propeller board can process the photocell blocking/unblocking and sending of print command to the serial board that quickly? The message to be printed would be static, and consist of 21 characters (including 3 spaces.)
Thanks,
Steve
Thanks,
Steve
Comments
According to the manual:
[noparse][[/noparse]quote]
Inter-column delay (ASCII 067) or “feed rate” of the inkjet nozzle, between 0.1 and 25.5 ms (i.e., a value of 15 is 1.5 ms)
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21 characters that don't change is no problem at all. Just load the data into the EPROM directly through a USB cable.
There is a quick and easy mode to start out, then there are lots of DIY options. In some ways, it is a 'tell all' of how the InkJet came to be and how it works.
It can do vertical surfaces[noparse][[/noparse]I had doubts about that] because there apparently is a collasping bladder and a sponge that feed the ink via capillary forces. I still suspect horizontal surfaceswill be less problematic and the output faces down.
The little guy will shoot a bit of ink about 4 inches, but don't expect it to be clear at that distance.
The book that comes with the package can explain about movement versus clarity in great detail.
155 inches per second seems a bit of a blur on any printer.
I imagine it would be better if you could get momentary syncohronized stops or slow downs in that flow. Sustain the overall output speed but have it in some way be pulsing. Or if the head could nearly keep up and then jump back after each printing, you would probably sustain quality. {I know, that is all mechanical stuff}.
Basically the HP InkJet kit comes with a nice little board that can load a reasonably long string into ROM. I am not sure, but I think the text said·64 or 32·characters. Then you can just repeat that. There are timing controls available to synchronize movement.· You can even add a RTO and do a date stamp!
Areodynamics is your biggest dilema. This is an ink 'jet' and the little bubbles of ink that burst from it are subject to turbulence in the air.
With this unit you have 12 jets. Only to can fire two at the same time because of the turbulence. It is a burst, then wait situation.
Gadgetman provided the key number. This is all background info.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Post Edited (Kramer) : 3/7/2006 5:31:07 AM GMT
The Sx board is much faster and will print out a whole string of 32 characters from one triggering. It has to juggle all the printing activities [noparse][[/noparse]retaining a string in RAM, looking up in ROM, proper cycling, proper spacing.
Since you have only 21 characters in mind, it is well within range of RAM.· The narrow font would fit more easily within your 3" limitation.
The real questions is if you intend to use 12 or 6 dot column width as there are two character fonts.· The narrow font uses less ink, is less legible, and much faster to print [noparse][[/noparse]as line are one dot wide rather than two dots wide].
Still that 155inches per second / 3 inches comes out to printing 52 images per second.
Each image has 21 characteres [noparse][[/noparse]52x21= 1092] 1092 characters/second.
With your column firing at 0.1 mil second optimal, I see how you can just maybe·get the output speed to print a string that long.· In other words, I think you are right near the limit of the controller and the print head's output if you use the narrow font.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Post Edited (Kramer) : 3/5/2006 3:43:24 PM GMT