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 <neil.bay...@gmail.com> wrote: > On Sun, Jun 6, 2010 at 6:44 PM, Peter C. Wallace <p...@mesanet.com> 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 > Emc-users@lists.sourceforge.net > 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
