Homebrew_PCBs

> congratulation
> cold you post some picture of the equipment? and some schematics maybe?
> the fuser works ok even if you dont use it at full power.think of him as
> a light bulb.
> the new type fusers work at a lower temperature (around 120 celsis) the
> older around 180 celsius.youu could use the original stepper motor to
> drive the fuser.just make a driver for the stepper with L297 and 4 power
> fet transistors.(search the net for milling machines)
>

> Stefan,
>
> I know that the same approach is used in HP (and others) Laserjet
> Printers,
> meaning that for HP they 'cycle' the heater-bulb on-then-off to keep the
> fuser at a certain temperature while idle, using a thermostat
> arrangement.
> Some others just keep the light bulb at partial voltage to keep it
> warm. A
> partial-on bulb can last a very long time, but you use a lot of
> electricity
> and give off a lot of heat. HP (those engines are actually made by
> Cannon
> for HP) cycles the bulb to keep the temperature, then turns it on full
> blast
> during the fusing pass as the material "pulls the heat out of the fuser".
>
> Your process sounds exciting. I will look forward to pictures if you can
> share them.
>
>
> Sincerely,
>
> Larry Miner
> larry.miner@...
> Sandcarving / Glass Awards / Digital Photography
>
>

>Stefan,
>
>I know that the same approach is used in HP (and others) Laserjet Printers,
>meaning that for HP they 'cycle' the heater-bulb on-then-off to keep the
>fuser at a certain temperature while idle, using a thermostat arrangement.
>Some others just keep the light bulb at partial voltage to keep it warm. A
>partial-on bulb can last a very long time, but you use a lot of electricity
>and give off a lot of heat. HP (those engines are actually made by Cannon
>for HP) cycles the bulb to keep the temperature, then turns it on full blast
>during the fusing pass as the material "pulls the heat out of the fuser".
>
>Your process sounds exciting. I will look forward to pictures if you can
>share them.
>
>
>Sincerely,
>
>Larry Miner
>larry.miner@...
>Sandcarving / Glass Awards / Digital Photography
>
>
>
>-----Original Message-----
>From: Stefan Trethan [mailto:stefan_trethan@...]
>Sent: Sunday, February 08, 2004 12:31 PM
>To: Homebrew_PCBs@yahoogroups.com
>Subject: [Homebrew_PCBs] Fuser as Laminator - Result
>
>
>Hi all,
>
>Good news, the Fuser works perfectly.
>
><snip>
>
>(does anyone know if it harms the quartz heater lamp running
>on "orange" half power, because then i will add some hysteresis to get it
>either full on of full off....??)
>
>
><snip>
>
>
>
>Be sure to visit the group home and check for new Bookmarks and files:
>http://groups.yahoo.com/group/Homebrew_PCBs
>Yahoo! Groups Links
>
>
>
>

> Hi Larry,
>
> I am working in the same. I have a fuser of a HP 4L. Do you have
> information over the exactly frequency of operation for this fuser??
>
> When the paper (or the pcb) is running inside the fuser, then the fuser
> is
> all the time On or ever the fuser is on and off ?
>
> Thanks, and sorry by my english.
>
> Esteban Arias
> earias@...
>

> In my infinate wisdom, I built my pic programmer to program _only_

> 16F627 and '628 (both 28 pin). Now I am looking at other projects

> going to need more IO, so I need to built an "adapter" for these

> chips. I am looking for DIL pins that I can solder to the bottom of

> adapter and will plug into the 28 pin socket. Sort of like how the

> stamp does. I have no idea to their name or where to find them.
>
> Any ideas?
>
> Thanks

>On Tue, 10 Feb 2004 17:32:42 -0300, Esteban Arias <earias@...> wrote:
>
>>Thanks Stefan. I am writing directly to you, no to the list.
>>
>>Then, when your say:
>>
>>"i made a simple thermostat with a relais and a potentiometer, nothing
>>else needed"
>>
>>Do you are working with the temperature sensor inside of fuser ?
>>the original sensor?
>>
>>It is possible see a diagram of your circuit ?
>>
>>I am very interested in this project.
>>
>>Thanks,
>>
>
>it is very possible.
>you could write this on-list, it would not be off topic (as i know steve).
>especially when it is silent around he allows pretty far OT topics...
>
>
>i have drawn a quick schematic.
>attached.
>
>It is a shame that is is so simple (i went to a school for control
>engineering).
>it could be much better, but it works so perfectly that i have no
>intention to change it.
>because the Fuser is such a big mass it works as integrating element and
>the simple on/off approach
>has such good results.
>
>with a mechanical relais you would need to add some hysteresis.
>if you have no solid state relais you can simply take a scr, triac, or a
>FET, or whatever you like
>most.
>
>If you need help with the thermostat i will gladly help..
>
>ST
>
>

--- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> wrote:
> I thought the 628 was an 18 pin chip. :)
>
> You might want to look at mill-max dip IC sockets. They make
fairly
> long soldertail sockets. the pins are 20 mils wide and 170 mils
> long. That might work though its a hack. mouser has them. p789
of
> current catalog.
>
> I'd suggest you skip the socket stuff altogether and build an ICSP
> header on your target hardware. You could get an 18 pin socket and
> solder on the 5 wires you need for the 5 (or 10) pin ISCP socket.
> ICSP is 10X easier than prying the chip out of its socket and
> sticking it into a programmer *every* *time* you make a change.
> Also, you can just ICSP to a seperate socket.
>
> Another approach is to get a "dip clip" and connect the appropriate
> pins to the ISCP pins on your programmer. Then to program a chip
in
> circuit, you just clip on and program away.
>
> Phil
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "Anthony Toft" <toftat@c...>
> wrote:
> > In my infinate wisdom, I built my pic programmer to program
_only_
> the
> > 16F627 and '628 (both 28 pin). Now I am looking at other projects
> and I am
> > going to need more IO, so I need to built an "adapter" for these
> bigger
> > chips. I am looking for DIL pins that I can solder to the bottom
of
> my
> > adapter and will plug into the 28 pin socket. Sort of like how
the
> basic
> > stamp does. I have no idea to their name or where to find them.
> >
> > Any ideas?
> >
> > Thanks

----- Original Message -----
From: "Anthony Toft" <toftat@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, February 11, 2004 1:26 AM
Subject: [Homebrew_PCBs] DIL pins


> In my infinate wisdom, I built my pic programmer to program _only_ the
> 16F627 and '628 (both 28 pin). Now I am looking at other projects and I am
> going to need more IO, so I need to built an "adapter" for these bigger
> chips. I am looking for DIL pins that I can solder to the bottom of my
> adapter and will plug into the 28 pin socket. Sort of like how the basic
> stamp does. I have no idea to their name or where to find them.

They are called turned-pin SIL headers. Preci-DIP makes the ones I use,
available from Rapid Electronics, Farnell, etc. They come in 32-way strips
and are cut to the required length.

Leon
--
Leon Heller, G1HSM
Email: aqzf13@...
My low-cost Philips LPC210x ARM development system:
http://www.geocities.com/leon_heller/lpc2104.html

> Thanks Stefan for the schematic. Now I have a good idea over the circuit.
>
> Today I search in my house and find the main board of the printer. I
> review
> the pcb and find the components asocciates to the fuser; BCR8PM a 8A,
> 600V
> triac. I think use the same triac for driver the fuser but with your
> circuit.
>
> The service manual say over the internal thermistor: "TH901". I think it
> is
> a 10 K thermistor. it is ok for your circuit ?
>
> Thanks,
>
> Esteban Arias
> earias@...
>

>On Tue, 10 Feb 2004 21:19:48 -0600, Esteban Arias <earias@...>
>wrote:
>
> > Thanks Stefan for the schematic. Now I have a good idea over the circuit.
> >
> > Today I search in my house and find the main board of the printer. I
> > review
> > the pcb and find the components asocciates to the fuser; BCR8PM a 8A,
> > 600V
> > triac. I think use the same triac for driver the fuser but with your
> > circuit.
> >
> > The service manual say over the internal thermistor: "TH901". I think it
> > is
> > a 10 K thermistor. it is ok for your circuit ?
> >
> > Thanks,
> >
> > Esteban Arias
> > earias@...
> >
>
>hi,
>
>10k thermistor is well posible.
>
>you want to use a triac, this needs to be triggered.
>
>
>it will work with my circuit but would need 1 more component.
>
>You can't connect the triac to my circuit without isolation.
>The temperature sensor in the fuser is not isolated for 220V you may
>damage the sensor and endanger yourself.
>
>The common procedure would be to use a optocoupler.
>
>(this is the same as in my solid state relais. it is just
>a optocoupler and a triac.)
>
>There are Triac optocouplers (consisting of a light-sensitive triac and a
>diode).
>these are nice for such applications. (but any other optosiolator will do).
>
>Tell me what you have at hand, i think the HP printer triggers the triac
>with a opto
>too so this will not be a problem.
>
>If you need help with a circuit tell me which parts you have.
>
>The printer has powered the fuser - so it must contain all components you
>need
>(spare the potentiometer). No need to go shopping i think.
>
>
>
>ST

> Why the hell did it print on the aluminium foil?
> simple standard kitchen foil.
>
> (i tried with a old toner cartridge containing tha drum also, the sharp
> edges could possibly harm the drum.).
> looks promising printing on copper, doesn't it?
>

> Stefan Trethan wrote:
>
>
>> Why the hell did it print on the aluminium foil?
>> simple standard kitchen foil.
>>
>> (i tried with a old toner cartridge containing tha drum also, the sharp
>> edges could possibly harm the drum.).
> > looks promising printing on copper, doesn't it?
>>
>
>
> Note the surface has to hold an electrostatic image to pick up the
> toner.

> Most oxides aren't that conductive, so would hold an image well enough
> for the
> time required. Copper oxide is a lot more conductive than most though.

>
> Really it is worth trying though, may well be even the aluminum it's
> not
> really an oxide layer but fluxes etc from making the foil, although if
> the
> aluminum is bare it surface oxidizes very readily. Anything that is
> insulative
> enough to let it hold the image that will not later interfere with the
> etching
> after the toner is applied should work. It's something I've had on a
> list of
> things to try for a long time, but the paper toner method works great
> and I just
> haven't bothered. And to get the best bang out of this, modifying a
> laser
> printer to print straight on board would be idea. I have a spare laser
> printer
> or two just for this, but it's way on down the list of things to do for
> me. The
> paper method works and only leaves one laser printer sitting on my desk
> so it's
> hard to work on having two sitting there.. :) But laser straight to
> board would
> be excellent in the long run, I have a good spare 1200 DPI laser on hand.
>
> Alan
>

> Pictures? Please?
>
> Sounds cool.
>
> - Robert

> I wonder which numbers we are talking here - how many
> volts are normally on the different wires?
>
> thanks
>
> st

>-----Original Message-----
>From: Stefan Trethan [mailto:stefan_trethan@...]


>Its just a piece of aluminium foil with X-es on it.
>if you don't trust me i can scan it (which i yould fake of course)
>but it is really like on paper.

> 5 to 15KV says my faulty memory.
>
> OK, not faulty just disorganized.
>
> Steve
>

>
> It's not that I don't trust you, but I feel that I can judge the quality
> of
> the transfer better by seeing pictures than by you describing it... A
> picture's worth a couple thousand words.
>
> I was just wondering if the toner adhered completely (due to the
> different
> coefficients of thermal expansion and conductivity of the aluminum as
> compared to paper), whether there were pinholes, approximately how thick
> the
> toner layer was, etc.
>
> - Robert
>

> No. The paper "charges" in the laser-printer just like your PLASTIC
> (non-conductive) comb charges on a very dry day when you comb your
> hair. The copper
> is obviously a GOOD conductor, a dead-short to ground, so NO "charge"
> will
> build up, which would attract the toner-powder.
>

----- Original Message -----
From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, February 25, 2004 3:40 AM
Subject: Re: [Homebrew_PCBs] Laser printer - experts please explain


>
> > No. The paper "charges" in the laser-printer just like your PLASTIC
> > (non-conductive) comb charges on a very dry day when you comb your
> > hair. The copper
> > is obviously a GOOD conductor, a dead-short to ground, so NO "charge"
> > will
> > build up, which would attract the toner-powder.
> >
>
> Well then, i thought the same.
>
> BUT why then works Aluminium foil?
>
>
> What i wanted to do is isolate the PCB so there is no short to ground.
> i want to put it on a carriage, of teflon or such, which has the
> appropriate
> HV source connected to it. To charge the whole board.
> The copper conducts, correct, but it can still hold a charge.
>
>
> I wonder how bad/good a printer will work if the first corona wire is
> completely
> off.
> I looked further and the aluminium foil has to short it out, it just has
> to, there
> is a grounded area just in front of this wire where it passes between a
> metal roller and
> bar.
>
>
> I will try to unplug the corona wire somehow, and see what happens, but
> this HV wiring is pretty
> well covered....
>
> ST
>
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
> Yahoo! Groups Links
>
>
>
>
>

> Dude, all this talk inspired me to shove a pcb thru the 4019 ... It
> works.
> err - well mostly

> I don't think it matters if it shorts to ground, The whole corona wire
> assembly is metal. I believe the static charge is so influential that it
> can
> overcome any grounding, It only makes the toner come off the drum. any
> substrate, Paper, copper, aluminum, or otherwise, If it's between the
> drum,
> and the discharge corona - it's getting toner'd
>

>
> it has not to hold the image i think.
> the electrostatic image is only at the drum.
> the paper is charged the whole surface the same, no matter if black or
> white.
> then this charge attracts the toner from the drum (which is only present
> where the black is).
>

>
> Yes I was thinking more the direct draw method than what's going on
> in a
> laser printer. There are printable foil sheets etc, but I'd assume
> they're
> coated to both protect the drum and cut the conduction. It's still an
> evenly
> conductive surface coming into contact with a surface trying to hold a
> charged
> image, supposed to cause image smearing and other problems. Still it
> was on my
> own list of things to try eventually too. Be sure and try oxide layers
> etc on
> the PCB, may improve the image and or adhesion.
>

> As noted in the later messages, the fuser wasn't made for this and is
> much
> too cool to heat up the board fully. Might be able to heat the board to
> say
> 120F then pass it through, don't want to go over 140F or so though since
> that's
> headed towards the toner melt point and you also don't want to damage
> the drum,
> not sure what it's coating could handle.

>
> Can always bake the board for a few minutes later to get a better
> melt and
> adhesion. Since it's much easier to control the temp and time after the
> fact it
> should be possible to melt it just enough to stick well without
> spreading.

>
> Expect to ruin the drum etc in the short term, but find a cheap
> cartridge
> printer and it's only $60 or $80, so if it lasts well enough for 100 or
> 200
> boards with care it's still little more than a 50 cent paper etc.
>

----- Original Message -----
From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, February 25, 2004 6:49 PM
Subject: [Homebrew_PCBs] Distance Paper/Drum in a Laser


>
>
> I just tried to figure out if the paper needs to be touching the drum.

From what I remember of my days at Rank-Xerox, with Xerox photocopiers the
paper was always in close contact with the drum. It was in fact stuck to it
by the electrostatic charge on the drum, and had to be released after
exposure and toner transfer by a sort of air knife, IIRC.

Leon
--
Leon Heller, G1HSM
Email: aqzf13@...
My low-cost Philips LPC210x ARM development system:
http://www.geocities.com/leon_heller/lpc2104.html

>>own list of things to try eventually too. Be sure and try oxide layers
>>etc on
>>the PCB, may improve the image and or adhesion.
>>
>
>
> i do really think there is no need to isolate the surface.
>

> I would rather not use a fuser at all but a infrared heater lamp.
> it is simple to set up if you already converted it to a carriage (flatbed)
> printer.
> just take the quartz lamp out of the fuser and move the pcb past (slow).
> there can be no smearing of the image then.
>

>
> spreading is mostly a effect of pressure, not heat alone.
> if you just heat it without pressure i assume there will be no spreading
> at all.
> (to be tried in experiment)

> I'm looking for a printer for very cheap, i would buy myself another for
> the normal
> printing stuff and convert the LJiiiD, but it is only 300DPI.
> Especially printers with problems like "pulls in several pages at once"
> or "always a paper jam" are very cheap, and this is not really something
> important
> for printing on pcbs.
>
> still, i want it really cheap, as i am not sure if it works at all, so
> this will take a while.
>

> if the attachment comes thru its of a laser printing onto copper foil
> about 1/2 of it got toner to stick and a few spots the toner stuck then
> peeled back off and a few other places hardly got any at all
>
> there might be some tricks to get better results but a quicky
> experement didnt turn out as well as expected YMMV
>
> Brian

> if the attachment comes thru its of a laser printing onto copper foil
> about 1/2 of it got toner to stick and a few spots the toner stuck then
> peeled back off and a few other places hardly got any at all
>
> there might be some tricks to get better results but a quicky
> experement didnt turn out as well as expected YMMV
>
> Brian

> I'll take a look at what that takes, I've always assumed it's just
> higher charging voltage to attract more toner etc but could be done in
> other
> ways. It may just be a set charging voltage then the laser just
> partially
> discharges even the black areas too. Simply upping the high voltage a
> bit may
> be all it takes.
>
> Alan
>
>

>
> Using the same post in multiple groups, are you? (not this one).
> clever....
>

>
> How do i make a copper oxyde layer (not that i say i will do it but just
> in case.....)
>

>
> but you could try to make it as wide as possible.
>
> A schematic of the power supply would be useful to figure out how it
> works, but i guess
> it can be done with some back engineering. I think a 20 or 30 percent more
> will certainly
> work without arcing or such.
>

>
>
> What i suggest to test:
>
> let the copper stripe through the printer halfway, and then switch off the
> power.
> now open the cover and take out the drum (with the cartridge).
>
> Now see how much toner is left on the drum after the point of contact, and
> how much
> is there before. compare to the areas where paper is.
>

>
> I did execute the described experiment.
>
> i taped a stripe of aluminium foil on one half ot the page.
> then i printed a page with X all over.
> cut the power as it was halfway through.
>
>
> Inspection of the srum shows just what i thought.
>
> before point of contact:
> clear image, thick.
>
> after point of contact on paper half:
> very faint residue, if you don't know what it is you couldn't read it.
>
> on aluminium half:
> about half the amount of toner still on the drum.
> image printed on aluminium foil but not as dense as on paper (holes too).
>
>
> for me this shows my guess with "charge shorted but some toner still
> transferring"
> was very close, even the 50/50 is about what i see here.
>

>
> After reading through the HowStuffWorks, the copper/aluminum being
> conductive
> is the problem. The paper isn't oppositely charged from the drum. The
> toner is
> positive, the drum is negative to pick up, and the paper is then more
> negative
> to attract the toner from the drum. The paper has first the charging
> corona and
> then another discharging after to unstick the paper from the drum.

> The paper
> underneath will keep the copper from directly shorting the
> charge/discharge
> wires as long as they are on the underside,

> but the copper on top will equalize
> the charge on that side or short if they're on top, so once it gets to
> the detac
> wire it'll have both neg and pos and be whatever shade of neutral the
> relative

> charges on the wire make. 50% less sounds about right, they may not
> need as
> much opposite on the detac just to unstick the paper.
>
> Note with a copper board there would be no tendency to wrap around
> the drum,
> you could remove the detac wire and possibly get an excellent print with
> a fully
> charged copper plate, just watch out for the static charge near any
> electronics
> afterwards since it's not being discharged during the printing.

>
> Now I really want to find a good upright printer as in their drawing
> that has
> a straight mechanical path with a little case modification. I'm now
> fairly sure
> the direct to copper can be made to work, and the fusing part is just a
> matter
> of heat and slower speed to get that working so should be easy enough.
> As good
> as toner transfer is damn it'd still be nice to not mess with the
> paper. The
> amount of toner etc on a normal page would be fine if it were all on the
> copper
> and fused well, so I don't think other mods would really be necessary.
>
> Alan
>

> Stefan Trethan wrote:
>
> >
> > I did execute the described experiment.
> >
> > i taped a stripe of aluminium foil on one half ot the page.
> > then i printed a page with X all over.
> > cut the power as it was halfway through.
> >
> >
> > Inspection of the srum shows just what i thought.
> >
> > before point of contact:
> > clear image, thick.
> >
> > after point of contact on paper half:
> > very faint residue, if you don't know what it is you couldn't read it.
> >
> > on aluminium half:
> > about half the amount of toner still on the drum.
> > image printed on aluminium foil but not as dense as on paper (holes
> too).
> >
> >
> > for me this shows my guess with "charge shorted but some toner still
> > transferring"
> > was very close, even the 50/50 is about what i see here.
> >
>
>
> After reading through the HowStuffWorks, the copper/aluminum being
> conductive
> is the problem. The paper isn't oppositely charged from the drum.
> The toner is
> positive, the drum is negative to pick up, and the paper is then more
> negative
> to attract the toner from the drum. The paper has first the charging
> corona and
> then another discharging after to unstick the paper from the drum.
> The paper
> underneath will keep the copper from directly shorting the
> charge/discharge
> wires as long as they are on the underside, but the copper on top will
> equalize
> the charge on that side or short if they're on top, so once it gets to
> the detac
> wire it'll have both neg and pos and be whatever shade of neutral the
> relative
> charges on the wire make. 50% less sounds about right, they may not
> need as
> much opposite on the detac just to unstick the paper.
>
> Note with a copper board there would be no tendency to wrap around
> the drum,
> you could remove the detac wire and possibly get an excellent print
> with a fully
> charged copper plate, just watch out for the static charge near any
> electronics
> afterwards since it's not being discharged during the printing.
>
> Now I really want to find a good upright printer as in their
> drawing that has
> a straight mechanical path with a little case modification. I'm now
> fairly sure
> the direct to copper can be made to work, and the fusing part is just
> a matter
> of heat and slower speed to get that working so should be easy
> enough. As good
> as toner transfer is damn it'd still be nice to not mess with the
> paper. The
> amount of toner etc on a normal page would be fine if it were all on
> the copper
> and fused well, so I don't think other mods would really be necessary.
>
> Alan
>
>
>
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
>
> ------------------------------------------------------------------------
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>
> Basic operation, in most laser printers, is based on electrostatics a
> old art, thanks to zerox. The drum or image roll is coated with a
> photoconductive coating. Which is charged with a high voltage as it
> rotates. The laser beam is modulated with the data image and shot
> onto the drum. That beam causes the photoconductor on the drum to
> conduct and discharge thru the coating to the drum ground. The next
> step in the drums path is the developer which lightly dusts the drum
> surface with toner. While there are several styles in this
> operation, the end result is the toner sticks to the drum where it is
> held by the remaining charge. Then next step is the image transfer.
> Or whats known as the transfer station in the drums path. The drum
> now meets up with the paper, both moving at the same speed so the
> image remains stable and clear. With the paper between the drum and a
> high voltage charge on a corona wire, the toner jumps off the drum
> thru the air toward the charge and ends up landing on the paper. The
> paper then travels to the preheater and into the fuser area of the
> printer and is pressed into the paper using a hot roll along with a
> backup roll. The hot toner melts into the paper. What us home pc
> makers are trying to do is keep the toner from sticking to the paper
> so well. Fuser oil or coatings on the paper keep the toner from
> locking down. Getting that drum image transfered to a sheet of
> copper will be a feat. The copper has to be moving at the same speed
> as the paper would be. The electrostatics for image transfer are
> critical for focus. The sheet of copper will be like a brick wall to
> the corona wire charge. After transfer takes place the left over
> toner and charge have to be removed. Sometimes another corona wire
> with a diffrent charge is in the drums path, some times a cleaner
> station to brush the left overs of the image off the drum. Then the
> drum is ready for a repeat for the next scan from the laser. While I
> don't know how to get that image on to a pc blank, I do know that is
> won't be easy or quick.

>>backup roll. The hot toner melts into the paper. What us home pc
>>makers are trying to do is keep the toner from sticking to the paper
>>so well. Fuser oil or coatings on the paper keep the toner from
>>locking down.

>>copper will be a feat. The copper has to be moving at the same speed
>>as the paper would be.

>>critical for focus. The sheet of copper will be like a brick wall to
>>the corona wire charge.

>>toner and charge have to be removed. Sometimes another corona wire
>>with a diffrent charge is in the drums path, some times a cleaner
>>station to brush the left overs of the image off the drum. Then the
>>drum is ready for a repeat for the next scan from the laser. While I
>>don't know how to get that image on to a pc blank, I do know that is
>>won't be easy or quick.

> Stefan Trethan wrote:
>
>
> Be damned if my LaserJet 6L didn't just print onto a taped on piece of
> aluminum foil just like it was paper. Next to try a much larger piece
> and full
> circuit this evening, but what just came out looks great.
>
> Alan
>

>
> my IIID is known for producing very low toner thickness.
> maybe your printer produces enough even without charging anything...
>
> ST

>
>>
>> my IIID is known for producing very low toner thickness.
>> maybe your printer produces enough even without charging anything...
>>
>> ST
>
>
> My LJ4 did poor solids, but if I use Acrobat files, the fills come
> out much more solid.
>
> Dave
>
>

> Still, that is impressively good for just a simple straight shot at it.
> Solid prints should be well within striking distance with a little work
> from that good of a starting point.
>
> I'm still thinking an oxide layer would be the best thing to try.
> Simple to make, less conductive, tend to be more 'sticky' than bare metal,
> and unlike most coatings etc the copper oxide will still etch easily. Just
> the brown like old PCB or a penny not the true green stuff of course..
>
> And that turned out way better than I'd have expected for just bare
> copper, all things considered. Looks like print density might even fix it,
> I'm assuming you had the 'Black' checked off in Eagle but make sure it's
> also set highest in your print driver too, some will interfere. We're
> going to be screwing up the printers for normal use anyway, even if it took
> a simple mod to make the printer print 'super black' beyond what it's
> normal settings could do it'd still be well worth it. I'll take a look at
> what that takes, I've always assumed it's just higher charging voltage to
> attract more toner etc but could be done in other ways. It may just be a
> set charging voltage then the laser just partially discharges even the
> black areas too. Simply upping the high voltage a bit may be all it takes.
>
> Alan

> that was printed from a PDF of the GameBoy PIO cartridge here
> http://marc.rawer.de/Gameboy/ top layer
>
> I ran it with just the default settings on a HP LJ1200 from a cold start
> the copper foil is a strip of 1.25" wide slug and snail tape from
> the lawn and garden dept. ,for some reason slugs wont crawl over
> copper but they love aluminum especially if its a beer can
> (mmmmm... beer :)
> once it was on the paper I gave it a scrub with a scotchbrite pad
> to rough it up a bit to hold the toner and gave it a swipe with acetone
> to clean off any oil
>
> offhand I'm thinking something smaller might work better
> maybe the Pic sip from the Eagle single sided tutorial or a
> basic stamp clone or SIMM Stick format board ,something like that
>
> or it might just take a tew tweaks to the settings like you say
> I was thinking of puting the tape on a transparency sheet to make
> a sort of home brew flex circuit
>
> Brian

On Fri, 27 Feb 2004 17:54:34 -0500, Alan King <alan@...> wrote:

> Stefan Trethan wrote:
>
> Had a thought that we probably need a very high value resistor
> between the
> corona wire and the metal surface. While the voltage is reasonably
> high, the
> capacity of a sheet of paper would be almost nil, it's almost purely a
> static
> charge with almost no current. I can just see a sheet of metal hitting
> the drum
> and not only the contact line transferring but 1/4" up the drum
> discharging and
> a ton of toner falling off. May still work ok really since the drum
> coating has
> to be high resistance to hold the image. But it'd cost almost nothing
> to use a
> good resistor and not depend solely on the drum coating, and it may be
> necessary
> for reliable operation. Maybe even megaohms since the voltage is high
> and the
> current should be very low. Corona wire supply is probably very light
> to begin
> with, but I would still bet it is many times what would possibly come
> off of the
> sheet of paper after passing it.
>
> Alan

> agree completely.
> how about a blade of ESD plastic brushing over the pcb?
> i don't quite remember the resistance but maybe it is reasonably low.
> otherwise a simple resistor will do.
>
> ST

> I have a 1200 DPI older laser in the attic too, got it for $5 at the
> local
> hamfest since it was so heavy and gives an error code. Never even
> really looked
> at it though, only got it because I know the drums cost hundreds for it,
> but
> never sold it off. Time to take a look I think..
>
> Alan
>
>

>>I have a 1200 DPI older laser in the attic too, got it for $5 at the
>>local
>
>
> You see, one can never keep enough stuff....
> I dunno why some other people always need to say "get that ugly stuff out
> of here"
> or "other people throw it out and you drag it home - typical".
> Only because it is a little bit defective it isn't useless, is it?
>

> And would likely be better off to still just sell the drum from the
> 1200 DPI
> and buy two LJ 6L's or similar anyway. The 600 DPI approaches the limit
> of what
> you can do much of by hand. 1200 may be a little sharper etc, but a bit
> of
> overkill for just homemade PCBs.
>
> Alan
>
>

>
> > And would likely be better off to still just sell the drum

> > 1200 DPI
> > and buy two LJ 6L's or similar anyway. The 600 DPI approaches

> > of what
> > you can do much of by hand. 1200 may be a little sharper etc,

> > of
> > overkill for just homemade PCBs.
> >
> > Alan
> >
> >
> i think 600dpi is sufficient...
>
> st

> you can do much of by hand. 1200 may be a little sharper etc, but a

> overkill for just homemade PCBs.
>
> Alan

> please help me understand why 600 is so good. I'm not disputing it,
> mind you but it seems kind of at the edge. If I am doing the math
> correctly, a 10 mil trace on a 600 DPI device is 6 dots wide. 8 mil
> is less than 5 dots. That seems kind of tight to me but maybe its
> ok. With my ink jet (1440 dpi) and copier (not sure what its
> effective DPI is but its pretty high), I get really clean traces even
> at 8 mil. I can get them to transfer but am fighting smearing which I
> believe to be due to poor temperature control.
>

> 600 is not so good, it is just the lower limit i assumed.
> and lower dpi means older, and thus cheaper (especially the toner).

> please help me understand why 600 is so good. I'm not disputing it,
> mind you but it seems kind of at the edge. If I am doing the math
> correctly, a 10 mil trace on a 600 DPI device is 6 dots wide. 8 mil
> is less than 5 dots. That seems kind of tight to me but maybe its
> ok. With my ink jet (1440 dpi) and copier (not sure what its
> effective DPI is but its pretty high), I get really clean traces even
> at 8 mil. I can get them to transfer but am fighting smearing which I
> believe to be due to poor temperature control.
>