Optical Encoders

[Michael GilliganParticipant @michaelgilligan61133]

I have just stripped down a Hewlet Packard 1350 All-in-One Printer/Scanner, for the "Useful Bits".

To my surprise; there are no Stepper Motors in this device.

Scanner Drive, Print-Head Positioning, and Paper Feed are all done with DC Motors.

The Paper Feed has an Encoder Disk on the end, and the Print Head reads a Linear Encoder that runs the full width of the paper. … Both of are printed transparencies … I have not yet checked the resolution, but they are very fine. Both run through Slotted Encoders.

The motors drive through a mix of plastc gears and micro-pitch toothed belts, and there the usual shafts and rollers to salvage.

Definitely one to Recycle … BUT "Caveat Dismantlor" there may be some ink residue inside; so don't wear light coloured Chinos.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Linear and Rotary

[Billy MillsParticipant @billymills]

HP have not used steppers in low cost printers for many years, just cheap brushed DC PM motors and printed plastic encoders. There is some complex gearing in some models with one way devices so that you feed paper one way and do cleaning chores the other way- that's why they often make busy noises without any paper movement after power-up.

Some models have a six channel peristaltic pump which transfers the inks into holding tanks then back- that way you can measure optically how much ink is actually left. You might also find a ccd camera in some all-in-one models.

Billy.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, even the print head in HP A0 printer has a linear encoder, and thats getting on a bit (just like it's owner) not going to bother worrying about it's resolution.

Regards Nick.

[Michael GilliganParticipant @michaelgilligan61133]

Thanks for the comments

The motors do look cheap; although the plastic gears are very well moulded, and I was delighted to find the micro-pitch belts and toothed pulleys [these seem very difficult to buy, and I need some].

What intrigued me was those Encoders [Strip and Disk] … there must be somewhere we could re-use them.

MichaelG.

[Author]

Posts