no it used a hardware counter which fired interrupts then optical strip state was checked and the motor switched on or off to advance/retard for the next interrupt, the astute will notice a lack of true control and a vertical line would show error noise.
Dave Caroline On Mon, Jun 7, 2010 at 4:22 AM, Neil Baylis <neil.bay...@gmail.com> wrote: > 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 > <dave.thearchiv...@gmail.com>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 <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 >> > > > > -- > 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 > 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
