Canon Automatic Print Head Alignment... How?

Nifty

Printer VIP
Administrator
Joined
Nov 3, 2004
Messages
3,046
Reaction score
1,405
Points
337
Location
Bay Area CA
Printer Model
CR-10, i560 ,MFC-7440N
I've had this question for a while and thought I'd ask.... how does the Canon do an automatic print head alignment?

I see the paper advance and then pull back as thought it is printing and then examining what it just printed. Any ideas?
 

Grandad35

Printer Master
Platinum Printer Member
Joined
Feb 24, 2005
Messages
1,669
Reaction score
182
Points
223
Location
North of Boston, USA
Printer Model
Canon i9900 (plus 5 spares)
Nifty-Stuff,

I opened the printer cover, held down the "cover closed" switch and watched as it did the automatic portion of the head alignment procedure. My i9900 has a light on the left rear corner of the head assembly, and there must be an associated pickup that senses the presence or absence of ink from the light that is reflected from the white paper. During the automatic head alignment, ink rectangles are printed and the head then scans the light over the edges of the squares to see where they were printed.
 

Nifty

Printer VIP
Administrator
Joined
Nov 3, 2004
Messages
3,046
Reaction score
1,405
Points
337
Location
Bay Area CA
Printer Model
CR-10, i560 ,MFC-7440N
GD, you're a genius. I just did the same (I bent a paperclip and taped it so it would depress the cover switch). Sure enough there is a tiny red LED on the left of the printhead that "scans" the paper after it prints. I wonder what that little LED scanner could be programmed to do... scan B/W 2 color images??? :)

I wonder if printing on black paper would mess up the scanner as I assume it is looking for reflections (or absence of) on the paper.

Also, when mine runs in seems to only print cyan and black. I've not seen it print any of the other colors during auto, but prints them all during manual alignment.

Well I thought this was so cool that I took a video. It is grainy, dark and shaky, but still cool! AVI 1.8 mb.:
http://www.nifty-stuff.com/gallery/albums/inkjet-refill-1/canon_head_alignment.avi
 

BlasterQ

Printer Guru
Joined
Feb 16, 2005
Messages
137
Reaction score
0
Points
109
Yeah, when I did the auto print head alignment, it printed only black and cyan, and I thought I had a clogged printhead, because I was expecting it to use all the cartridges.
 
Top