Dave, do they use the optical strip transitions to time the firing of the ink droplets, or is it only used to control the print head?
On Sun, Jun 6, 2010 at 7:55 PM, Dave Caroline <[email protected]>wrote: > I was the coder for a version of printer based on the Canon A1210 and > later the PJ1080 they were very early ink jets from the mid 1980's, > they had servo drive and optical strip and we drove them as fast as > possible but were limited by the possibility of burning out the motor. > The optical strip had had two images the one for the servo > loop(regular bars) and the other for home at each end. > Just had to look at my old code to remind myself. Bugs did have the > unfortunate bang when ther head hit the end stop the anti copy code I > put in messed with the timing and a large bang was the result, it kept > the ripoff merchants at bay. > > Dave Caroline > > On Mon, Jun 7, 2010 at 3:10 AM, Neil Baylis <[email protected]> wrote: > > On Sun, Jun 6, 2010 at 6:44 PM, Peter C. Wallace <[email protected]> > wrote: > > > > Umm, not any more, all the inkjets I've seen are really cheap servo > systems > >> (battery toy type motors and a linear mylar strip encoder) > >> > > > > Yes, they really cut the cost out of these things. The motors generally > > don't have ball bearings, just bushings. The worst kind of motor to use > > with continuous radial loads, but there ya go, that's what they use. > > > > One printer I recently gutted (Canon, I think) had no feedback at all. > There > > was just a simple DC motor to drive the carriage. They were depending on > the > > motor moving at constant speed with constant voltage, I guess. No limit > > switches, either. Perhaps they monitor motor current to know when it's at > > the limit. > > > > > >> I think homing against a stop is OK with a torque controlled system > (move > >> slow > >> and limit torque when homing) If your encoder has an index then this > would > >> give an accurate home. > >> > > > > Actually, I hadn't thought of that. My encoder does have an index, but I > > don't have torque control. The drive does have a current limit, so maybe > I > > could use that. > > > > > >> Of course without limit switches, theres nothing to stop such a system > from > >> slamming into the stop at full torque with drive or software error.. > >> > > > > Yes. I was planning to not have drive or software errors ;-) > > > ------------------------------------------------------------------------------ > > ThinkGeek and WIRED's GeekDad team up for the Ultimate > > GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the > > lucky parental unit. See the prize list and enter to win: > > http://p.sf.net/sfu/thinkgeek-promo > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > ------------------------------------------------------------------------------ > ThinkGeek and WIRED's GeekDad team up for the Ultimate > GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the > lucky parental unit. See the prize list and enter to win: > http://p.sf.net/sfu/thinkgeek-promo > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- http://www.pixpopuli.com ------------------------------------------------------------------------------ ThinkGeek and WIRED's GeekDad team up for the Ultimate GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the lucky parental unit. See the prize list and enter to win: http://p.sf.net/sfu/thinkgeek-promo _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
