iGen3 principles

[realrdp]

Would like to know the exact Xerography principles on the iGen3, Please be as technical as possible.

 

[Stiv]

It is magic.

 

[ddigen3]

No, Stiv, the unicorns & wizards who live inside ARE MAGIC. Don't confuse the guy. He's new.

 

[igen jim]

Once upon a time there was a big bang.

 

[archipelago]

Direct magic is good.

I've never been lucky enough to be able to work with an igen; I'm enough of a geek that I always enjoy finding someone who feels like talking about "theory and practice." I know what parts go where and what they do real-world basically, but going from the idea of how it works to a working machine is magic to me. Maybe a half dozen major principles but a half million tweaks to get to where we are today! It would be fun if you get the service manuals and schematics for every machine built and page through them It would be really fun to get to page through the files of what worked and what didn't and how things were modified as each press came from idea to practice. Could lose a lot of time though in that library.

Somewhat related broad-brush-stroke older thread -> http://www.colorprintingforum.com/xerox-iGen/igen3-vs-docucolor-technology-291.html

 

[realrdp]

Thanx! Knowing that the principle is Xerography(well ingrained at RIT in the 70's!), I am just wondering the steps of and how the image is generated on the belt, and then transfered to the substrate. I also am trying to understand the benefits of "image positioning" on the sheet on the iGen, compared to "sheet positioning", which is the "gripper/side-guide" principle of offset. Why can't the gppr/sdgd function be used, instead of the image being positioned on a given sheet. It seems that we are trapped into relying on the tolerances of mill trimmed digital size sheets. If any of them are off by thousands of an inch, any given image on the sheet may or may not fit the die strike, which could and HAS presented issues. OF COURSE the mill trimmed digital sheets can be pre-trimmed, before loading the draw, but isn't that an extra step in production OR is it just "production as usual"?

 

[igen jim]

realrdp
WOW how long have you been in the trade?

 

[David M. Baker]

He had me at "hello!"

 

[ddigen3]

realrdp,

I feel your pain! When I was introduced to the iGen3 and was told there are no grippers, I just about called them liars. Then the process was explained and shown to me, and it took me about a year to get comfortable with the idea.

We do have to check every ream that comes in, even from the mill, and re-cut to size, if necessary. Its a bother, to say the least.

The good news is, in most cases, it IS "close enough" for our general audience. When there's a die involved, we typically reduce the size of the sheet down to 8.5 x 11 or so, in order to have less "fish tailing" or registration issues.

Good luck!!

 

[iGenTech]

iGen Xerographics Process

Xerographics relies on five steps.
Charging, discharging, the development of the latent image on the photoconductor,
transferring the image from the photoconductor to a sheet of paper, clean the photoconductor.

The iGen relies on the same five steps.
Xerographics starts with Magenta then Yellow, Cyan and Black.
The process is the same for each color all on a single pass one after another.
First the P/R belt is charged then its discharged with at LED ROS then developed.
Pretransfer Dicorotron helps loosens up the toner for transfer.
Transfer tab blade is used to help transfer the image from the P/R to the paper.
Transfer Dicorotron As its name suggest it transfers the image to the paper.
Detack loosens the paper up to keep it from sticking to the P/R.
Preclean Dicorotron loosens toner up that was left behind from transfer.
The Cleaner cleans off toner that whats left behind.

I don't know that you need to know the exact voltages for Charge, Development, transfer, and cleaning and so on.
If you were having some xerographic problem I might could help you with that.


Registration: LOL The Real "Magic"
IOI (Image to Image) alignment is set by the MOB Sensors:
MOB Sensors detect the IOI Registration Marks that are xerographically placed in none print areas on the P/R Belt.

IOP (Image on Paper) alignment is from the regtransport:
Registration Sensor Bar Assembly has 10 Process Edge Sensor and 3 CCD Sensors used to calculate alignment.
As it uses 15 Registration Drive Rolls to place the page in the correct location and put it in time to meet the image
on the P/R belt.

 

[ddigen3]

This is all very accurate. However, there need be mention of the pixie dust used during the "Please Wait: Adjusting Print Quality" phase.

Hey iGenTech, thanks for all the great info...and in such detail. Welcome to the forum!!