Homebrew PCBs

I've been looking at Volkan's tutorial and I'd like some clarification
on a few points:

1- why does the paper needed to be emulated... won't the PCB tray act
like paper?

2- which sensors will need to be emulated?

3- Are there any more specifics on what needs to be monitored?

4- how is the moved optical sensor used.

Any other clarification would be helpful as well.

I have the repair manual for this printer, but I'd like a little bit
more on the theory behind the electronics modifications.  If I can get
a bit more information, I'd be interested in releasing a step-by-step
how-to on the printer, complete w/ my own source code and
schematics/pcb layout to help others create functioning PCB printers.

On Sat, 26 Aug 2006 19:15:28 +0200, purdueee_06  
<nathanael.huffman@...> wrote:

> I've been looking at Volkan's tutorial and I'd like some clarification
> on a few points:
> 1- why does the paper needed to be emulated... won't the PCB tray act
> like paper?

If you look at my mod, i've done just that. The tray has a cutout on the  
side so you can put it in the printer before printing and the traction  
roller already grabs it. I simply moved the optical sensor so it senses  
the "delayed" leading edge directly, where the cutout is.

> 2- which sensors will need to be emulated?

Depends on printer. With mine it was only the paper detection sensor on  
the back. In the service util there is talk about a paper sensor on the  
head, but i couldn't confirm that so far nor did it give me grief.

> 3- Are there any more specifics on what needs to be monitored?
> 4- how is the moved optical sensor used.

Dunno what you mean with the last two.

> Any other clarification would be helpful as well.
> I have the repair manual for this printer, but I'd like a little bit
> more on the theory behind the electronics modifications.  If I can get
> a bit more information, I'd be interested in releasing a step-by-step
> how-to on the printer, complete w/ my own source code and
> schematics/pcb layout to help others create functioning PCB printers.

I dunno why volkan needed the electronics for the 4200, i do not know that  
printer. All i can say is with the c84 it worked nicely the way i did it.  
The trick is to get the cutout the right length so the time delay between  
the motor starting to pull and the edge triggering the sensor is right. I  
worked that length out by fixing the sensor and making a very far back  
cutout at first (actually i just used tape protruding over the edge  
instead of a cutout). Now you can manually pre-feed the carrier into the  
printer variable distances and find for which starting positions the  
printer will detect a successful feed. When you know the valid distance  
you can make the final cutout just the right length so you only need to  
feed a few mm.

BTW i found the optical sensor is less precise than the timing/number of  
steps of the paper feed. So to get accurate repeatability i made a stop to  
push the carrier against. If you always put the tray in the same starting  
position there is zero error.

ST

I tried to answer your questions. Keep in mind that
this is my way of doing you can find much easier ways.


> 1- why does the paper needed to be emulated... won't
 the PCB tray act like paper?
On CX4200/CX4800 printers there is a paper sensor to
detect objects around the printing area and to find
the edge of the paper. Tray itself can not be used
like paper since you need to feed tray before starting
printing. You need to be sure that tray is aligned
properly before starting printing. Another issue is,
since tray is a metal part you can easily destroy
abrasive roller during feeding. In my solution tray
always exist below printing area. So you need to find
a method to emulate behavior of the paper otherwise
you will get paper jam error. 
What I am doing is very easy, I am counting signals
coming from x and y axis optical encoders and
depending on position of head (x-axis) and y-axis
(tray/paper) I am sending high/low signal  in parallel
to paper sensor. Both of paper end and paper sensor
have open collector/drain output so no problem to
drive for a short period of time.

> 2- which sensors will need to be emulated?
Paper sensor on inkjet head and paper end sensor need
to be emulated
> 3- Are there any more specifics on what needs to be
> monitored?
No.
> 4- how is the moved optical sensor used.
If you look at the behavior of the printer during
initial paper feeding, it takes the paper (checks
paper end sensor) and checks whether there is a
reflection from the paper in defined x/y axis range,
after then it moves the paper in reverse direction
(-y) slowly till finding edge of the paper by this way
printer sets it origin precisely.  
I am using optical sensor to detect the slot on the
tray and control the paper sensor. Otherwise it is not
easy to minimize the y axis alignment errors in double
side PCB or solder resist printing.  This method works
very well.
 
> Any other clarification would be helpful as well.
> 
> I have the repair manual for this printer, but I'd
> like a little bit  more on the theory behind the 
> electronics modifications.  If I can get
> a bit more information, I'd be interested in
> releasing a step-by-step
> how-to on the printer, complete w/ my own source
> code and
> schematics/pcb layout to help others create
> functioning PCB printers.
Having service manual that's great. I got it a few
weeks a go . I will also give the schematic and
program but I need to touch a little bit to the
schematic and code. There are so many unnecessary
things exist on schematic and in the code coming from
early tests.
If you are in USA or time difference in an acceptable
range we can communicate using messanger I will be
happy to help you during your modifications.  
Good luck,
Volkan

Thanks for your responses, I think I have a clearer view about how
your modifications work.  I wanted to get a better understanding of
the work involved before I started modifying things.  I'm hoping to
put the hooks in for my circuit and make the mechanical modifications
this week, but we'll see.

I am in the US so if I have more questions, I'll try to catch you on
messenger.  I expect I'll have more questions about the process as I
get more into it.  

One last general question is about the ink carts.  Can the origial
ones be refilled or will I need to buy another type?

Thanks,

purdueee

You can refill original ones no problem but before
refilling be sure that it is empty.
Volkan 

--- purdueee_06 <nathanael.huffman@...> wrote:

> Thanks for your responses, I think I have a clearer
> view about how
> your modifications work.  I wanted to get a better
> understanding of
> the work involved before I started modifying things.
>  I'm hoping to
> put the hooks in for my circuit and make the
> mechanical modifications
> this week, but we'll see.
> 
> I am in the US so if I have more questions, I'll try
> to catch you on
> messenger.  I expect I'll have more questions about
> the process as I
> get more into it.  
> 
> One last general question is about the ink carts. 
> Can the origial
> ones be refilled or will I need to buy another type?
> 
> Thanks,
> 
> purdueee
> 
> 
> 
>