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Re: [Homebrew_PCBs] Forget the clothes iron - get a laminator

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  • Philip Pemberton
    In message ... You can say that again.. Four screws, then it lifts up and out. Very nice. Check the continuity between the
    Message 1 of 12 , Jul 2, 2005
      In message <op.ssntfm02mg0lsf@tu-x2pj5qeyp2u4>
      "Stefan Trethan" <stefan_trethan@...> wrote:

      > The LJIII has the fuser unit easily removeable,

      You can say that again.. Four screws, then it lifts up and out. Very nice.
      Check the continuity between the pins on the lamp connector before you buy
      one though - replacing the thermofuse is very difficult, if not impossible.
      It's even worse if the fuser lamp's burned out.

      > and has a thermistor on it
      > as any fuser (still need meter for initial adjustment). There might even
      > be a triac on that small board on the side, not sure.

      No - there's an optosensor; the triac is in the AC Power Unit (the thing
      that takes the mains inlet connector). ISTR there's a 24V drive circuit for
      the erase lamps, but that's it.

      > I guess you would
      > need to get one of the gears out of the printer too, or find some other
      > way to drive it. I don't remember if it is easy to modify for thicker
      > material.

      It isn't too hard. Remove the front paper guide (2 screws) and the flip-down
      guide at the back (2 more screws). The silver roller is the heated roller,
      the red one is a rubber pressure roller. The big problem is that the fuser
      feeds REALLY thick stuff (e.g. PCBs) at an angle of about 30 degrees, which
      means the fuser needs mounting at an angle. I'll see if it does the same
      thing with 0.8mm laminate in a bit, or if feeding from the back makes any
      difference.

      I need to glue a bit of the plastic on my fuser back together though - I
      slipped and broke one of the mounting arms that holds the AC power connector.
      Next job is to gut the AC power module and pray that the triac and
      zero-crossing optotriac are intact.

      Next job is to find a motor. Something that'll run the fuser so that the
      board gets fed in at about 0.1ips.

      > I'm running my fuser at 160C.

      Exactly the same as the HP recommended temperature then. ISTR the LJ3
      increases the fuser temp to 180C when it's working on thick media and the
      thermofuse trips at 210C.

      Later.
      --
      Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB,
      philpem@... | ViewFinder, 10BaseT Ethernet, 2-slice,
      http://www.philpem.me.uk/ | 48xCD, ARCINv6c IDE, SCSI
      ... Live every day like it's your last, because someday you'll be right.
    • Stefan Trethan
      On Sat, 02 Jul 2005 12:45:44 +0200, Philip Pemberton ... I don t consider the thermofuse a problem, the LJIII has thermoswitch though, which i have replaced on
      Message 2 of 12 , Jul 2, 2005
        On Sat, 02 Jul 2005 12:45:44 +0200, Philip Pemberton
        <philpem@...> wrote:

        >
        > You can say that again.. Four screws, then it lifts up and out. Very
        > nice.
        > Check the continuity between the pins on the lamp connector before you
        > buy
        > one though - replacing the thermofuse is very difficult, if not
        > impossible.
        > It's even worse if the fuser lamp's burned out.

        I don't consider the thermofuse a problem, the LJIII has thermoswitch
        though, which i have replaced on mine once (kapton tape rubbed through).
        Also, i think for PCBs it would be acceptable to bridge the thermofuse.
        Lamp must be good tho.

        > No - there's an optosensor; the triac is in the AC Power Unit (the thing
        > that takes the mains inlet connector). ISTR there's a 24V drive circuit
        > for
        > the erase lamps, but that's it.

        I see. Yes, now i remember seeing the triac in the AC PU when repairing a
        power problem.
        Just remembered a small PCB on the fuser and thought it might be.

        >
        >> I guess you would
        >> need to get one of the gears out of the printer too, or find some other
        >> way to drive it. I don't remember if it is easy to modify for thicker
        >> material.

        > It isn't too hard. Remove the front paper guide (2 screws)

        Really? Then i must have done something wrong - work on the front always
        required me to take of about 15 screws (the whole front "panel" thing),
        even for getting out the DC PSU. I thought that is the more nasty section
        of the printer. Maybe i missed a easy way to do it.
        But still - how many of todays printers still work if you remove ALL
        plastic and a good deal of steel? If you take off a side-panel on a new
        printer the unit usually falls apart into a thousand pieces.

        > and the flip-down
        > guide at the back (2 more screws). The silver roller is the heated
        > roller,
        > the red one is a rubber pressure roller. The big problem is that the
        > fuser
        > feeds REALLY thick stuff (e.g. PCBs) at an angle of about 30 degrees,
        > which
        > means the fuser needs mounting at an angle. I'll see if it does the same
        > thing with 0.8mm laminate in a bit, or if feeding from the back makes any
        > difference.

        Maybe you can remove some guard? why is it feeding at such an odd angle.
        (it sounds almost as if it is a sick animal..... ;-)

        > I need to glue a bit of the plastic on my fuser back together though - I
        > slipped and broke one of the mounting arms that holds the AC power
        > connector.
        > Next job is to gut the AC power module and pray that the triac and
        > zero-crossing optotriac are intact.
        > Next job is to find a motor. Something that'll run the fuser so that the
        > board gets fed in at about 0.1ips.

        Chicken grill motor ;-)

        >
        >> I'm running my fuser at 160C.
        > Exactly the same as the HP recommended temperature then. ISTR the LJ3
        > increases the fuser temp to 180C when it's working on thick media and the
        > thermofuse trips at 210C.

        My PCB fuser is from a ricoh copier, and it had "thermal cutoff 160°C"
        written on top, so that's what i used.
        The copier fusers often have a knob on the lower roller, which you can
        turn by hand to remove a jam. Neat to override the drive motor. I don't
        think i will ever use the LJIIID fuser for PCBs, 'cause that beast just
        isn't going to die any time soon.

        ST
      • Philip Pemberton
        In message ... Only if you don t mind causing a fire if/when the temperature controller jams on :) ... ISTR you only need
        Message 3 of 12 , Jul 2, 2005
          In message <op.staas3yqmg0lsf@tu-x2pj5qeyp2u4>
          "Stefan Trethan" <stefan_trethan@...> wrote:

          > Also, i think for PCBs it would be acceptable to bridge the thermofuse.

          Only if you don't mind causing a fire if/when the temperature controller jams
          on :)

          > Really? Then i must have done something wrong - work on the front always
          > required me to take of about 15 screws (the whole front "panel" thing),
          > even for getting out the DC PSU. I thought that is the more nasty section
          > of the printer. Maybe i missed a easy way to do it.

          ISTR you only need to open the flip-out section, then remove the four screws
          that hold the fuser in place. I'm not 100% sure about that though - I'd need
          to check the service manual.
          Getting the top cover off is difficult, but it's worth it for the big, meaty
          stepper motor. Shame it's got such an odd shaft shape though - sort of a
          spiral. Never seen anything like it.

          > But still - how many of todays printers still work if you remove ALL
          > plastic and a good deal of steel? If you take off a side-panel on a new
          > printer the unit usually falls apart into a thousand pieces.

          :)

          > Maybe you can remove some guard? why is it feeding at such an odd angle.
          > (it sounds almost as if it is a sick animal..... ;-)

          Dunno.. Might have something to do with trying to feed it 1.6mm PCB laminate.
          Or the fact that the rollers are slightly offset from each other - the red
          rubber roller is slightly further back inside the casing.

          > Chicken grill motor ;-)

          If I can find one.

          Later.
          --
          Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB,
          philpem@... | ViewFinder, 10BaseT Ethernet, 2-slice,
          http://www.philpem.me.uk/ | 48xCD, ARCINv6c IDE, SCSI
          ... Some people are, through no fault of their own, sane.
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