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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Photocopier - paper scratches on the OPC
ie the normal paper or dust slight scratches , not down to the metal drum
from loose screw or swarf. All quite normal for any OPC. Usually this is ok but the original toner for this m/c not available, requiring second 1 only source, supposed compatible, formulation. Very fine scratches seem to hold the toner , ie exposed bits of latent image retain the toner in the scratches and so deposit as fine lines on the paper. If too much toner passed to the OPC then more and more lines appear, so only possible to produce grey rather than black output. The ac cleaning voltage is now at maximum of 2.5 KV but some lines are still present with a grey image rather than black. Anyone happen to know what needs adding to the toner to make it less sticky or whatever ? or some other procedure. I'm assuming the narrow scratches are physically holding the toner but thats only guessing really, decreasing the transfer voltage of course produces a lighter image and still transfers the lines, so not an option. Physically cleaning the OPC or leaving the background heater on all the time makes no difference. I'm wondering if the toner is too oily and decanting to a tumbler with blotting paper lining would remove some of the oiliness, before returning to the hopper. Anyone know of a test for oiliness that gives some sort of numerical result ? Incidently anyone know what the marking B stands for, on the preset for adjusting the 200 to 250V dc voltage of the OPC relative to frame and what this voltage is called ? The other presets are marked TR for transfer and AC for the ac cleaning voltage |
#2
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Photocopier - paper scratches on the OPC
N_Cook wrote in message
... ie the normal paper or dust slight scratches , not down to the metal drum from loose screw or swarf. All quite normal for any OPC. Usually this is ok but the original toner for this m/c not available, requiring second 1 only source, supposed compatible, formulation. Very fine scratches seem to hold the toner , ie exposed bits of latent image retain the toner in the scratches and so deposit as fine lines on the paper. If too much toner passed to the OPC then more and more lines appear, so only possible to produce grey rather than black output. The ac cleaning voltage is now at maximum of 2.5 KV but some lines are still present with a grey image rather than black. Anyone happen to know what needs adding to the toner to make it less sticky or whatever ? or some other procedure. I'm assuming the narrow scratches are physically holding the toner but thats only guessing really, decreasing the transfer voltage of course produces a lighter image and still transfers the lines, so not an option. Physically cleaning the OPC or leaving the background heater on all the time makes no difference. I'm wondering if the toner is too oily and decanting to a tumbler with blotting paper lining would remove some of the oiliness, before returning to the hopper. Anyone know of a test for oiliness that gives some sort of numerical result ? Incidently anyone know what the marking B stands for, on the preset for adjusting the 200 to 250V dc voltage of the OPC relative to frame and what this voltage is called ? The other presets are marked TR for transfer and AC for the ac cleaning voltage I should have said the voltage on the centre of the revolving magnet developer drum , not to the OPC, the retraction voltage ? The votage that means the toner powder on the OPC that has become discharged from the exposure light is pulled off, back to the toner supply side, leaving the latent image. These fine line toner deposits are adhering more than the 250V "retraction voltage ?" will pull off but will pull off with the 7.3KV transfer voltage to the paper. Anyone know of a source of plain carbon black, fine ground, without silicone oil/surfactants added , to dilute the supposed proper toner. |
#3
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Photocopier - paper scratches on the OPC
In that are is what looked like an afterthougt 1W resistor to ground,
marked brown black brown. Surely not if a few hundred volts there. With a good light brought into the area I could then see it is brown black purple. Just an ordinary looking MO resistor, enamelled ,no glass encapsulation, but 1 Gigohm. |
#4
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Photocopier - paper scratches on the OPC
In that are is what looked like an afterthougt 1W resistor to ground,
marked brown black brown. Surely not if a few hundred volts there. With a good light brought into the area I could then see it is brown black purple. Just an ordinary looking MO resistor, enamelled ,no glass encapsulation, but 1 Gigohm. Wouldn't that be 100M? (10 x 10^7) |
#5
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Photocopier - paper scratches on the OPC
"William Sommerwerck" wrote in
: In that are is what looked like an afterthougt 1W resistor to ground, marked brown black brown. Surely not if a few hundred volts there. With a good light brought into the area I could then see it is brown black purple. Just an ordinary looking MO resistor, enamelled ,no glass encapsulation, but 1 Gigohm. Wouldn't that be 100M? (10 x 10^7) yes. -- Jim Yanik jyanik at kua.net |
#6
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Photocopier - paper scratches on the OPC
Jim Yanik wrote in message
... "William Sommerwerck" wrote in : In that are is what looked like an afterthougt 1W resistor to ground, marked brown black brown. Surely not if a few hundred volts there. With a good light brought into the area I could then see it is brown black purple. Just an ordinary looking MO resistor, enamelled ,no glass encapsulation, but 1 Gigohm. Wouldn't that be 100M? (10 x 10^7) yes. -- Jim Yanik jyanik at kua.net I'm not used to seing that colour combination. Measured about 1000Meg, by comparison with a glass cased 1Gohm , with a high voltage source, it is grey not purple on the third band on rechecking. |
#7
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Photocopier - paper scratches on the OPC
"N_Cook" wrote in
: Jim Yanik wrote in message ... "William Sommerwerck" wrote in : In that are is what looked like an afterthougt 1W resistor to ground, marked brown black brown. Surely not if a few hundred volts there. With a good light brought into the area I could then see it is brown black purple. Just an ordinary looking MO resistor, enamelled ,no glass encapsulation, but 1 Gigohm. Wouldn't that be 100M? (10 x 10^7) yes. -- Jim Yanik jyanik at kua.net I'm not used to seing that colour combination. Measured about 1000Meg, by comparison with a glass cased 1Gohm , with a high voltage source, it is grey not purple on the third band on rechecking. I'm surprised it would stay 1G for any length of time,with an enamel coating. maybe you could post a pic of it.I wonder who makes them? -- Jim Yanik jyanik at kua.net |
#8
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Photocopier - paper scratches on the OPC
Jim Yanik wrote in message
... "N_Cook" wrote in : Jim Yanik wrote in message ... "William Sommerwerck" wrote in : In that are is what looked like an afterthougt 1W resistor to ground, marked brown black brown. Surely not if a few hundred volts there. With a good light brought into the area I could then see it is brown black purple. Just an ordinary looking MO resistor, enamelled ,no glass encapsulation, but 1 Gigohm. Wouldn't that be 100M? (10 x 10^7) yes. -- Jim Yanik jyanik at kua.net I'm not used to seing that colour combination. Measured about 1000Meg, by comparison with a glass cased 1Gohm , with a high voltage source, it is grey not purple on the third band on rechecking. I'm surprised it would stay 1G for any length of time,with an enamel coating. maybe you could post a pic of it.I wonder who makes them? -- Jim Yanik jyanik at kua.net Its just a light blue bodied resistor that looks like any other except for an unusual colour code. It must be there to discharge any accumulated charge inside the developer chamber. A resistor with a crimp eye terminal at either end, looking a bit afterthoughtish. Whether it is 500M or 2000Meg probably does not matter. I imagine it could be difficult to make a high resistivity spiral of metal oxide, from my own attempts at making resistive compound for 1 meg pot tracks, very patchy resistivity As for main thread I got into the generator circuit and temporarily upped the retract ? voltage up to 350V , for a test. Black lines still there and I think the image intensty was reduced as well, ie wanted charged, latent image bits, partially retracted back to the developer, so no solution there. Apparently, from an industrial chemist, it is possible to get fine ground pure carbon black from chemical supply companies for some sort of filters , not activated charcoal. All laser and copier toner these days have silicone oil added , perhaps to avoid the use of silicone oil bath/wicks at the output fuser stage. Enough oil carries through to the output to keep the paper from sticking to the supposed non-stick finish of the fuser roller or its pressure roller. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
#9
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Photocopier - paper scratches on the OPC
N_Cook wrote:
ie the normal paper or dust slight scratches , not down to the metal drum from loose screw or swarf. All quite normal for any OPC. It's perfectly normal for the OPC to have mild scratches on it. As long as it's not down to the metal. (Which will give you white lines along the print.) Usually this is ok but the original toner for this m/c not available, requiring second 1 only source, supposed compatible, formulation. Very fine scratches seem to hold the toner , ie exposed bits of latent image retain the toner in the scratches and so deposit as fine lines on the paper. That's more likely to be due to dirt on the laser window. Give it a wipe & a blow. A stray hair stuck in there, or in the laser window of the cartridge will give you a line down the page. If too much toner passed to the OPC then more and more lines appear, so only possible to produce grey rather than black output. The ac cleaning voltage is now at maximum of 2.5 KV but some lines are still present with a grey image rather than black. Anyone happen to know what needs adding to the toner to make it less sticky or whatever ? or some other procedure. I'm assuming the narrow scratches are physically holding the toner but thats only guessing really, decreasing the transfer voltage of course produces a lighter image and still transfers the lines, so not an option. There's nothing 'sticky' about the toner. It adheres to the drum from electrostatic attraction only. If it's sticking to the drum when it shouldn't be, there's something wrong with the HV, or the IR laser or cleaning light is not wiping the charge from the drum as it should. Physically cleaning the OPC or leaving the background heater on all the time makes no difference. I'm wondering if the toner is too oily and decanting to a tumbler with blotting paper lining would remove some of the oiliness, before returning to the hopper. Anyone know of a test for oiliness that gives some sort of numerical result ? Dry toner is *never* 'oily'. It's micron-sized particles. Incidently anyone know what the marking B stands for, on the preset for adjusting the 200 to 250V dc voltage of the OPC relative to frame and what this voltage is called ? The other presets are marked TR for transfer and AC for the ac cleaning voltage 'B' = Bias. -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- |
#10
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Photocopier - paper scratches on the OPC
N_Cook wrote:
Jim Yanik wrote in message ... "N_Cook" wrote in : Jim Yanik wrote in message ... "William Sommerwerck" wrote in : In that are is what looked like an afterthougt 1W resistor to ground, marked brown black brown. Surely not if a few hundred volts there. With a good light brought into the area I could then see it is brown black purple. Just an ordinary looking MO resistor, enamelled ,no glass encapsulation, but 1 Gigohm. Wouldn't that be 100M? (10 x 10^7) yes. -- Jim Yanik jyanik at kua.net I'm not used to seing that colour combination. Measured about 1000Meg, by comparison with a glass cased 1Gohm , with a high voltage source, it is grey not purple on the third band on rechecking. I'm surprised it would stay 1G for any length of time,with an enamel coating. maybe you could post a pic of it.I wonder who makes them? -- Jim Yanik jyanik at kua.net Its just a light blue bodied resistor that looks like any other except for an unusual colour code. It must be there to discharge any accumulated charge inside the developer chamber. A resistor with a crimp eye terminal at either end, looking a bit afterthoughtish. Whether it is 500M or 2000Meg probably does not matter. I imagine it could be difficult to make a high resistivity spiral of metal oxide, from my own attempts at making resistive compound for 1 meg pot tracks, very patchy resistivity As for main thread I got into the generator circuit and temporarily upped the retract ? voltage up to 350V , for a test. Black lines still there and I think the image intensty was reduced as well, ie wanted charged, latent image bits, partially retracted back to the developer, so no solution there. Apparently, from an industrial chemist, it is possible to get fine ground pure carbon black from chemical supply companies for some sort of filters , not activated charcoal. All laser and copier toner these days have silicone oil added , perhaps to avoid the use of silicone oil bath/wicks at the output fuser stage. Enough oil carries through to the output to keep the paper from sticking to the supposed non-stick finish of the fuser roller or its pressure roller. *NO!* That is NOT correct! Laser/copier toner is totally dry. The silicon oil is applied to the fuser roller by a wiper pad, & serves to prevent the 'cooked' toner on the paper from sticking to the fuser roller as it exits the fuser assembly. -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- |
#11
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Photocopier - paper scratches on the OPC
Bob Larter wrote in message
... N_Cook wrote: ie the normal paper or dust slight scratches , not down to the metal drum from loose screw or swarf. All quite normal for any OPC. It's perfectly normal for the OPC to have mild scratches on it. As long as it's not down to the metal. (Which will give you white lines along the print.) Usually this is ok but the original toner for this m/c not available, requiring second 1 only source, supposed compatible, formulation. Very fine scratches seem to hold the toner , ie exposed bits of latent image retain the toner in the scratches and so deposit as fine lines on the paper. That's more likely to be due to dirt on the laser window. Give it a wipe & a blow. A stray hair stuck in there, or in the laser window of the cartridge will give you a line down the page. If too much toner passed to the OPC then more and more lines appear, so only possible to produce grey rather than black output. The ac cleaning voltage is now at maximum of 2.5 KV but some lines are still present with a grey image rather than black. Anyone happen to know what needs adding to the toner to make it less sticky or whatever ? or some other procedure. I'm assuming the narrow scratches are physically holding the toner but thats only guessing really, decreasing the transfer voltage of course produces a lighter image and still transfers the lines, so not an option. There's nothing 'sticky' about the toner. It adheres to the drum from electrostatic attraction only. If it's sticking to the drum when it shouldn't be, there's something wrong with the HV, or the IR laser or cleaning light is not wiping the charge from the drum as it should. Physically cleaning the OPC or leaving the background heater on all the time makes no difference. I'm wondering if the toner is too oily and decanting to a tumbler with blotting paper lining would remove some of the oiliness, before returning to the hopper. Anyone know of a test for oiliness that gives some sort of numerical result ? Dry toner is *never* 'oily'. It's micron-sized particles. Incidently anyone know what the marking B stands for, on the preset for adjusting the 200 to 250V dc voltage of the OPC relative to frame and what this voltage is called ? The other presets are marked TR for transfer and AC for the ac cleaning voltage 'B' = Bias. -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- This is a conventional copier, not scanner/laser. Silicone oil wick/baths at the output have not been used on photocopiers since the days of sliding top ones, relying on silicones added (sub 1 percent) to the toner instead, not enough to appear oily to the touch but enough to make sure paper does not stick to fuser drum or silicone rubber pressure roller. The first one I came across to fix, was wet process toner in paraffin carrier, 1970s vintage, paper on a roll and a vicious guillotine. The toner these days is mainly carbon/charcoal black but also such as styrene ,styrene acrylic copolymer, polypropylene,metal complex dyes, methylmethacrylate,styrene butylarylate, silicones and oleic acid |
#12
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Photocopier - paper scratches on the OPC
"N_Cook" wrote in
: Jim Yanik wrote in message ... "N_Cook" wrote in : Jim Yanik wrote in message ... "William Sommerwerck" wrote in : In that are is what looked like an afterthougt 1W resistor to ground, marked brown black brown. Surely not if a few hundred volts there. With a good light brought into the area I could then see it is brown black purple. Just an ordinary looking MO resistor, enamelled ,no glass encapsulation, but 1 Gigohm. Wouldn't that be 100M? (10 x 10^7) yes. -- Jim Yanik jyanik at kua.net I'm not used to seing that colour combination. Measured about 1000Meg, by comparison with a glass cased 1Gohm , with a high voltage source, it is grey not purple on the third band on rechecking. I'm surprised it would stay 1G for any length of time,with an enamel coating. maybe you could post a pic of it.I wonder who makes them? -- Jim Yanik jyanik at kua.net Its just a light blue bodied resistor that looks like any other except for an unusual colour code. It must be there to discharge any accumulated charge inside the developer chamber. A resistor with a crimp eye terminal at either end, looking a bit afterthoughtish. Whether it is 500M or 2000Meg probably does not matter. I imagine it could be difficult to make a high resistivity spiral of metal oxide, from my own attempts at making resistive compound for 1 meg pot tracks, very patchy resistivity As for main thread I got into the generator circuit and temporarily upped the retract ? voltage up to 350V , for a test. Black lines still there and I think the image intensty was reduced as well, ie wanted charged, latent image bits, partially retracted back to the developer, so no solution there. Apparently, from an industrial chemist, it is possible to get fine ground pure carbon black from chemical supply companies for some sort of filters , not activated charcoal. All laser and copier toner these days have silicone oil added , perhaps to avoid the use of silicone oil bath/wicks at the output fuser stage. Enough oil carries through to the output to keep the paper from sticking to the supposed non-stick finish of the fuser roller or its pressure roller. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ toner is a wax compound.waxes are also lubricants. -- Jim Yanik jyanik at kua.net |
#13
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Photocopier - paper scratches on the OPC
On 6/13/2009 5:42 AM Jim Yanik spake thus:
toner is a wax compound.waxes are also lubricants. That's not my understanding: from what I've read, toner is basically a mixture of pigment (carbon black or equivalent) and plastic (styrene) that melts onto the printed substrate (paper). Maybe you're thinking of phase-change/sublimation printing (e.g., Xerox/Tektronix Phaser), which does use wax as the carrier. -- Found--the gene that causes belief in genetic determinism |
#14
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Photocopier - paper scratches on the OPC
David Nebenzahl wrote in message
.com... On 6/13/2009 5:42 AM Jim Yanik spake thus: toner is a wax compound.waxes are also lubricants. That's not my understanding: from what I've read, toner is basically a mixture of pigment (carbon black or equivalent) and plastic (styrene) that melts onto the printed substrate (paper). Maybe you're thinking of phase-change/sublimation printing (e.g., Xerox/Tektronix Phaser), which does use wax as the carrier. -- Found--the gene that causes belief in genetic determinism I would agree with that summary but add that there are surfactants added to assist in even distribution of the toner over the OPC, otherwise the coarse distribution of the iron filings transfer process would be rather patchy. |
#15
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Photocopier - paper scratches on the OPC
"N_Cook" wrote in
: David Nebenzahl wrote in message .com... On 6/13/2009 5:42 AM Jim Yanik spake thus: toner is a wax compound.waxes are also lubricants. That's not my understanding: from what I've read, toner is basically a mixture of pigment (carbon black or equivalent) and plastic (styrene) that melts onto the printed substrate (paper). Maybe you're thinking of phase-change/sublimation printing (e.g., Xerox/Tektronix Phaser), which does use wax as the carrier. Heh.I worked for TEK for 21.5 years. their thermal wax process is a sort of wax-jet deposition thru a printhead. I've had pretty good looks at TEK's printer mechanics. just feel the toner that's fused onto the paper;it feels waxy. Googling showed several references to wax for copier toner. -- Found--the gene that causes belief in genetic determinism I would agree with that summary but add that there are surfactants added to assist in even distribution of the toner over the OPC, otherwise the coarse distribution of the iron filings transfer process would be rather patchy. Isn't it done by electrostatics? -- Jim Yanik jyanik at kua.net |
#16
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Photocopier - paper scratches on the OPC
David Nebenzahl wrote:
On 6/13/2009 5:42 AM Jim Yanik spake thus: toner is a wax compound.waxes are also lubricants. That's not my understanding: from what I've read, toner is basically a mixture of pigment (carbon black or equivalent) and plastic (styrene) that melts onto the printed substrate (paper). Correct. Maybe you're thinking of phase-change/sublimation printing (e.g., Xerox/Tektronix Phaser), which does use wax as the carrier. That'd be my guess too. -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- |
#17
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Photocopier - paper scratches on the OPC
Jim Yanik wrote in message
... "N_Cook" wrote in : David Nebenzahl wrote in message .com... On 6/13/2009 5:42 AM Jim Yanik spake thus: toner is a wax compound.waxes are also lubricants. That's not my understanding: from what I've read, toner is basically a mixture of pigment (carbon black or equivalent) and plastic (styrene) that melts onto the printed substrate (paper). Maybe you're thinking of phase-change/sublimation printing (e.g., Xerox/Tektronix Phaser), which does use wax as the carrier. Heh.I worked for TEK for 21.5 years. their thermal wax process is a sort of wax-jet deposition thru a printhead. I've had pretty good looks at TEK's printer mechanics. just feel the toner that's fused onto the paper;it feels waxy. Googling showed several references to wax for copier toner. -- Found--the gene that causes belief in genetic determinism I would agree with that summary but add that there are surfactants added to assist in even distribution of the toner over the OPC, otherwise the coarse distribution of the iron filings transfer process would be rather patchy. Isn't it done by electrostatics? -- Jim Yanik jyanik at kua.net The rotating magnets + iron filings bring the toner close to the OPC and then the electrostatic voltage on the OPC, set up by the corona wire, pulls the toner across the gap. Then there should be an even charge distribution, but although very fine ground, it is finite size and the surfactants can help to allow easier flow. This maybe the key to the problem . What is the charge distribution over a semiconductor surface that instead of being perfectly smooth, has very fine scratches around it ? Maybe it is possible to reduce the corona voltage. Previously mistyped as 7.3KV, actually 8.3KV, I've not looked into that area, separate HV board somewhere, just measured the voltage at the corona housing . |
#18
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Photocopier - paper scratches on the OPC
I found the neat little Murata corona generator, marked 4.55KV, 0.3mA . I
don't know what the o/p voltage should be Corona measured as 8.7KV so something not right there, plenty of room to drop the corona voltage. Not got to the point of monitoring the lines to it yet nor tried the preset yet, lines to it are 2 grounds, supply, control, and one marked REM , any ideas what that one means ? |
#19
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Photocopier - paper scratches on the OPC
N_Cook wrote:
Jim Yanik wrote in message ... "N_Cook" wrote in : David Nebenzahl wrote in message .com... On 6/13/2009 5:42 AM Jim Yanik spake thus: toner is a wax compound.waxes are also lubricants. That's not my understanding: from what I've read, toner is basically a mixture of pigment (carbon black or equivalent) and plastic (styrene) that melts onto the printed substrate (paper). Maybe you're thinking of phase-change/sublimation printing (e.g., Xerox/Tektronix Phaser), which does use wax as the carrier. Heh.I worked for TEK for 21.5 years. their thermal wax process is a sort of wax-jet deposition thru a printhead. I've had pretty good looks at TEK's printer mechanics. just feel the toner that's fused onto the paper;it feels waxy. Googling showed several references to wax for copier toner. -- Found--the gene that causes belief in genetic determinism I would agree with that summary but add that there are surfactants added to assist in even distribution of the toner over the OPC, otherwise the coarse distribution of the iron filings transfer process would be rather patchy. Isn't it done by electrostatics? -- Jim Yanik jyanik at kua.net The rotating magnets + iron filings bring the toner close to the OPC Modern laser printers & copiers use monocomponent toner, which has the magnetic material in each toner particle. You're thinking of older systems, which used a separate magnetic 'developer' powder to carry the toner to the drum. -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- |
#20
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Photocopier - paper scratches on the OPC
On 6/14/2009 7:49 PM Bob Larter spake thus:
N_Cook wrote: The rotating magnets + iron filings bring the toner close to the OPC Modern laser printers & copiers use monocomponent toner, which has the magnetic material in each toner particle. You're thinking of older systems, which used a separate magnetic 'developer' powder to carry the toner to the drum. Reminds me of the old Kodak* copier I had when I owned a print shop; the previous owner had bought it for something ridiculous like less than $1000. The thing was a behemoth, and required lots of maintenance, but when it was running it would whip out good copies all day long and not even breathe hard. I remember having to replace various parts of the "developer" system in it. Very old school. * Actually Kodak/Heidelberg, during their short partnership in imaging systems. -- Found--the gene that causes belief in genetic determinism |
#21
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Photocopier - paper scratches on the OPC
The ps voltage was a bit high but not enough to push the corona voltage from
5.55KV to over 8KV. The preset only varied it a few hundred volts. Put a dropper in line and its now 5.8KV and working , subjectively, just as before - lines on the paper image. But these lines are no longer "burned" onto the OCD. Previously if you removed the corona housing and wire, then the lines still emerged onto the paper for a number of runs because of a build up on the OCD, that failed to clean off with AC and wiper blade. Now if you remove the corona the next output is plain white so the cleaning process can now cope with it. I tried changing the corona housing to a spare one but the lines are in exactly the same place. It is difficult convincing myself that the toner lies in fine lines on the OCD as there is no obvious repeat, coincident with the lines on the paper. There are hundreds of such fine lines with nothing making the most persistently tranferrd ones stand out. If the following makes no difference I will try the earlier OCD that worked fine but the original owner managed to scratch numerous deep lines axial to the drum so produced heavy black lines obscuring the image. If the lines stay in the same position then it will be a total mystery as I've cleaned ,twice now, all surfaces near the OCD path. I should have said these present lines are so fine they are just intrusive rather than blocking information. Going back to my original thinking, as this all started about coincident with forced change of toner supplier. I made up a test batch of some of the toner mixed about 2 :3 of charcoal sieved down to 75 microns, the thinking is it would dilurte an excess of oil/styrene. It takes a while for this to work through the feed system but so far the ratio of blackness of wanted image to tram lines has improved, I think. I can get hold of styrene and have plenty of silicone oil but how do you mix 98 percent sieved charcoal with 2 percent or so of liquids without clumping? At this rate I may as well try formulating my own toner . My set of old brass lab sieves go down to 75 micron, any ideas for a source of mesh of order 30 or 40 micron? |
#22
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Photocopier - paper scratches on the OPC
N_Cook wrote:
The ps voltage was a bit high but not enough to push the corona voltage from 5.55KV to over 8KV. The preset only varied it a few hundred volts. Put a dropper in line and its now 5.8KV and working , subjectively, just as before - lines on the paper image. But these lines are no longer "burned" onto the OCD. Previously if you removed the corona housing and wire, then the lines still emerged onto the paper for a number of runs because of a build up on the OCD, that failed to clean off with AC and wiper blade. Now if you remove the corona the next output is plain white so the cleaning process can now cope with it. I tried changing the corona housing to a spare one but the lines are in exactly the same place. It is difficult convincing myself that the toner lies in fine lines on the OCD as there is no obvious repeat, coincident with the lines on the paper. There are hundreds of such fine lines with nothing making the most persistently tranferrd ones stand out. If the following makes no difference I will try the earlier OCD that worked fine but the original owner managed to scratch numerous deep lines axial to the drum so produced heavy black lines obscuring the image. If the lines stay in the same position then it will be a total mystery as I've cleaned ,twice now, all surfaces near the OCD path. I should have said these present lines are so fine they are just intrusive rather than blocking information. Going back to my original thinking, as this all started about coincident with forced change of toner supplier. I made up a test batch of some of the toner mixed about 2 :3 of charcoal sieved down to 75 microns, the thinking is it would dilurte an excess of oil/styrene. It takes a while for this to work through the feed system but so far the ratio of blackness of wanted image to tram lines has improved, I think. I can get hold of styrene and have plenty of silicone oil but how do you mix 98 percent sieved charcoal with 2 percent or so of liquids without clumping? At this rate I may as well try formulating my own toner . My set of old brass lab sieves go down to 75 micron, any ideas for a source of mesh of order 30 or 40 micron? Jesus. You're sure trying to do this the hard way! Have you cleaned the laser module window, & tried swapping out the cartridge? -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- |
#23
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Photocopier - paper scratches on the OPC
Bob Larter wrote in message
... N_Cook wrote: The ps voltage was a bit high but not enough to push the corona voltage from 5.55KV to over 8KV. The preset only varied it a few hundred volts. Put a dropper in line and its now 5.8KV and working , subjectively, just as before - lines on the paper image. But these lines are no longer "burned" onto the OCD. Previously if you removed the corona housing and wire, then the lines still emerged onto the paper for a number of runs because of a build up on the OCD, that failed to clean off with AC and wiper blade. Now if you remove the corona the next output is plain white so the cleaning process can now cope with it. I tried changing the corona housing to a spare one but the lines are in exactly the same place. It is difficult convincing myself that the toner lies in fine lines on the OCD as there is no obvious repeat, coincident with the lines on the paper. There are hundreds of such fine lines with nothing making the most persistently tranferrd ones stand out. If the following makes no difference I will try the earlier OCD that worked fine but the original owner managed to scratch numerous deep lines axial to the drum so produced heavy black lines obscuring the image. If the lines stay in the same position then it will be a total mystery as I've cleaned ,twice now, all surfaces near the OCD path. I should have said these present lines are so fine they are just intrusive rather than blocking information. Going back to my original thinking, as this all started about coincident with forced change of toner supplier. I made up a test batch of some of the toner mixed about 2 :3 of charcoal sieved down to 75 microns, the thinking is it would dilurte an excess of oil/styrene. It takes a while for this to work through the feed system but so far the ratio of blackness of wanted image to tram lines has improved, I think. I can get hold of styrene and have plenty of silicone oil but how do you mix 98 percent sieved charcoal with 2 percent or so of liquids without clumping? At this rate I may as well try formulating my own toner . My set of old brass lab sieves go down to 75 micron, any ideas for a source of mesh of order 30 or 40 micron? Jesus. You're sure trying to do this the hard way! Have you cleaned the laser module window, & tried swapping out the cartridge? -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- This is conventional copier with document glass and toner hopper feed. The same problem must apply to cartridge/laser systems for when the original specified cartridges are no longer available and supposed replacement equivalents are not equivalent. Its just that the process (whatever it is) is otherwise going on , unseen , inside the cartridge. |
#24
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Photocopier - paper scratches on the OPC
I tried the original OCD with the deep scratch lines axial to the drum and
there is not the slightest hint of any of the thousands of paper scratch lines on the original, coming through to the paper, just the deep imperfections coming through. That is old OCD with the current toner produces a good black image with no tramlines. I'm wondering if too high a volts/mm in the active layer, from the corona wire being too high a voltage can cause damage. Somehow in conjunction with very fine scratches , give a concentrated charge distribution and very locally damage the germanium or cadmium sulphide or whatever the active layer is. With the problem OCD outside the machine I gave it a very close inspection and I can still not see any correlation between the paper scratch lines that cause tramline output and any of the thousands oif other possible ones. It is a continuum thing. If more toner is allowed through then more and more tramlines appear. I could understand it if some bits of hair conducted straight from corona to OCD to cause a few permanently affected rings but not this situation. |
#25
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Photocopier - paper scratches on the OPC
N_Cook wrote:
Bob Larter wrote in message ... N_Cook wrote: The ps voltage was a bit high but not enough to push the corona voltage from 5.55KV to over 8KV. The preset only varied it a few hundred volts. Put a dropper in line and its now 5.8KV and working , subjectively, just as before - lines on the paper image. But these lines are no longer "burned" onto the OCD. Previously if you removed the corona housing and wire, then the lines still emerged onto the paper for a number of runs because of a build up on the OCD, that failed to clean off with AC and wiper blade. Now if you remove the corona the next output is plain white so the cleaning process can now cope with it. I tried changing the corona housing to a spare one but the lines are in exactly the same place. It is difficult convincing myself that the toner lies in fine lines on the OCD as there is no obvious repeat, coincident with the lines on the paper. There are hundreds of such fine lines with nothing making the most persistently tranferrd ones stand out. If the following makes no difference I will try the earlier OCD that worked fine but the original owner managed to scratch numerous deep lines axial to the drum so produced heavy black lines obscuring the image. If the lines stay in the same position then it will be a total mystery as I've cleaned ,twice now, all surfaces near the OCD path. I should have said these present lines are so fine they are just intrusive rather than blocking information. Going back to my original thinking, as this all started about coincident with forced change of toner supplier. I made up a test batch of some of the toner mixed about 2 :3 of charcoal sieved down to 75 microns, the thinking is it would dilurte an excess of oil/styrene. It takes a while for this to work through the feed system but so far the ratio of blackness of wanted image to tram lines has improved, I think. I can get hold of styrene and have plenty of silicone oil but how do you mix 98 percent sieved charcoal with 2 percent or so of liquids without clumping? At this rate I may as well try formulating my own toner . My set of old brass lab sieves go down to 75 micron, any ideas for a source of mesh of order 30 or 40 micron? Jesus. You're sure trying to do this the hard way! Have you cleaned the laser module window, & tried swapping out the cartridge? -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- This is conventional copier with document glass and toner hopper feed. The same problem must apply to cartridge/laser systems for when the original specified cartridges are no longer available and supposed replacement equivalents are not equivalent. Its just that the process (whatever it is) is otherwise going on , unseen , inside the cartridge. Sorry, I had some sort of brainfart & was thinking that you were talking about a laser, not a copier. You should clean all the mirrors in the optical path, & look for stray hairs or other debris. Your problem is incredibly unlikely to be related to the composition of your toner. -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- |
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