OK, where's the developer (dc 242)

[Island]

Can someone give me a rundown of how the xerox trickle charge developer system works in my new dc242? (or have a little schematic they could share?)

(I'm just a printer, but want to have a basic understanding of how the machine works; up until this month I've used only canons since 2002)

[kalindd]

Nothing new or special. Just adding developer with toner. And taking some amount of the old developer out of the dev. cartridge.

[Island]

Thanks kalindd. I don't know if I have to return the empty toner carts yet to xerox so they can remanufacture them, so I can't cut one open to look Is the dev actually mixed with toner in the cart itself (only seeing one egress)? Is the old dev then flushed out to the waste toner container?

[kalindd]

Is the dev actually mixed with toner in the cart itself ?

Yes it is.

Is the old dev then flushed out to the waste toner container?

Yes it is

[mdsavage]

Just spoke to an ex xerox engineer today and I asked him where the developer goes. He said it attaches to drum to carry the toner on the drum. Once toner is transferred to belt the dev returns to developer tank. The reason it needs changing at approx 1 million copies is that it loses the ability to keep its magnetic charge. It will still be there, just exhausted needing a complete clean out and fresh developer adding. 1 million is just a guide. Patchy prints might mean it needs doing earlier. Mark

[Caffeine]

Just spoke to an ex xerox engineer today and I asked him where the developer goes. He said it attaches to drum to carry the toner on the drum. Once toner is transferred to belt the dev returns to developer tank. The reason it needs changing at approx 1 million copies is that it loses the ability to keep its magnetic charge. It will still be there, just exhausted needing a complete clean out and fresh developer adding. 1 million is just a guide. Patchy prints might mean it needs doing earlier. Mark

Haha, that's a bizarre, and significantly incorrect, explanation they gave you... The developer never leaves the developer assembly, except as waste to the waste container. Not in a properly operating system, anyway. The developer does indeed "carry" the toner, on a magnetic roll which is part of the developer assembly, and that roll come in close proximity to the drum. The toner being charged one way and the drum being charged another (thanks to being bombarded by the laser) causes the toner to "jump" from the weak grip of the developer on the magnetic roller onto the drum, in those areas which the laser unit charged only, of course. The magnetics of the roll and developer prevent the developer from jumping as well. (Not that it would in a normal situation. Each particle of developer is an order of magnitude heavier than each particle of toner.)

Once the toner is on the drum, the drum then rotated to come in contact with the accumulator belt. Again, static charges are used to cause the toner to transfer from the drum onto the belt. (This time they are in direct contact. No jumping.) A little bit of residual toner is left behind on the drum and this is cleaned off by a wiper blade and after a long trek makes its way to the waste container.

Once all four colors are collected on the belt, the complete image is then transferred to the paper again with static charges, this time between the belt and the 2nd BTR roller. The 2nd BTR roller is "pulling" the toner towards itself, but the machine slips a piece of paper in there first, so the paper gets it. (Again, direct contact, no jumping.) Once again, a little residual toner is left behind on the belt, it isn't a "perfect" transfer" and this also makes it to the waste container.

Toner occasionally gets onto the 2nd BTR roller, too, and it has a brush and a wiper blade to clean itself. The toner it cleans, however, stays inside the cavity of the 2nd BTR assembly. It isn't plumbed to the waste container.

To answer the original question, the developer and toner are mixed in the cartridge and fed together. The ratio of toner to developer is specific, but it can be fed in unevenly (since it is just loosely mixed in the cartridge) but this doesn't cause problems. To avoid developer build up in the developer assembly, a little bit of developer is sloughed off continuously, to the waste container. There is no way for the machine to differentiate between worn developer and new developer, so sometimes it is new stuff that gets dumped, but with a continuous supply coming in, it is still much much longer lasting.

Developer particles don't lose their magnetic properties, though that is commonly believed to be the reason they stop working well. The real reason is that they are very spiky, with lots of points and edges, when they are new. This gives lots of specific points for toner particles to "stick" to. As developer ages, abrasion of constantly going round and round smoothes them out and with fewer sharp edges and spikes, they can't carry as much toner, or as well. Yet they still take just just as much "space" in the dev assembly. Transfer quality is more affected the smoother it gets.

[mdsavage]

Haha, that's a bizarre, and significantly incorrect, explanation they gave you... The developer never leaves the developer assembly, except as waste to the waste container. Not in a properly operating system, anyway. The developer does indeed "carry" the toner, on a magnetic roll which is part of the developer assembly, and that roll come in close proximity to the drum. The toner being charged one way and the drum being charged another (thanks to being bombarded by the laser) causes the toner to "jump" from the weak grip of the developer on the magnetic roller onto the drum, in those areas which the laser unit charged only, of course. The magnetics of the roll and developer prevent the developer from jumping as well. (Not that it would in a normal situation. Each particle of developer is an order of magnitude heavier than each particle of toner.)

Once the toner is on the drum, the drum then rotated to come in contact with the accumulator belt. Again, static charges are used to cause the toner to transfer from the drum onto the belt. (This time they are in direct contact. No jumping.) A little bit of residual toner is left behind on the drum and this is cleaned off by a wiper blade and after a long trek makes its way to the waste container.

Once all four colors are collected on the belt, the complete image is then transferred to the paper again with static charges, this time between the belt and the 2nd BTR roller. The 2nd BTR roller is "pulling" the toner towards itself, but the machine slips a piece of paper in there first, so the paper gets it. (Again, direct contact, no jumping.) Once again, a little residual toner is left behind on the belt, it isn't a "perfect" transfer" and this also makes it to the waste container.

Toner occasionally gets onto the 2nd BTR roller, too, and it has a brush and a wiper blade to clean itself. The toner it cleans, however, stays inside the cavity of the 2nd BTR assembly. It isn't plumbed to the waste container.

To answer the original question, the developer and toner are mixed in the cartridge and fed together. The ratio of toner to developer is specific, but it can be fed in unevenly (since it is just loosely mixed in the cartridge) but this doesn't cause problems. To avoid developer build up in the developer assembly, a little bit of developer is sloughed off continuously, to the waste container. There is no way for the machine to differentiate between worn developer and new developer, so sometimes it is new stuff that gets dumped, but with a continuous supply coming in, it is still much much longer lasting.

Developer particles don't lose their magnetic properties, though that is commonly believed to be the reason they stop working well. The real reason is that they are very spiky, with lots of points and edges, when they are new. This gives lots of specific points for toner particles to "stick" to. As developer ages, abrasion of constantly going round and round smoothes them out and with fewer sharp edges and spikes, they can't carry as much toner, or as well. Yet they still take just just as much "space" in the dev assembly. Transfer quality is more affected the smoother it gets.

Thanks caffeine for such a detailed summary. I only believed the engineer because of the comparison to toner and dev life. He quoted the copy count of toner against developer so it did sound feasible that developer stayed in tank. Already learnt something i did not know. Seeing that i bought the xerox 242 to go it alone on looking after it, i can see the forum will be incredibly helpful and the moment i can give something useful back, i will. Currently doing a fiery repair install so no doubt that might be another separate post either for help or hopefully to mention any usefull observations.

[knightfall]

Haha, that's a bizarre, and significantly incorrect, explanation they gave you... The developer never leaves the developer assembly, except as waste to the waste container. Not in a properly operating system, anyway. The developer does indeed "carry" the toner, on a magnetic roll which is part of the developer assembly, and that roll come in close proximity to the drum. The toner being charged one way and the drum being charged another (thanks to being bombarded by the laser) causes the toner to "jump" from the weak grip of the developer on the magnetic roller onto the drum, in those areas which the laser unit charged only, of course. The magnetics of the roll and developer prevent the developer from jumping as well. (Not that it would in a normal situation. Each particle of developer is an order of magnitude heavier than each particle of toner.)

Once the toner is on the drum, the drum then rotated to come in contact with the accumulator belt. Again, static charges are used to cause the toner to transfer from the drum onto the belt. (This time they are in direct contact. No jumping.) A little bit of residual toner is left behind on the drum and this is cleaned off by a wiper blade and after a long trek makes its way to the waste container.

Once all four colors are collected on the belt, the complete image is then transferred to the paper again with static charges, this time between the belt and the 2nd BTR roller. The 2nd BTR roller is "pulling" the toner towards itself, but the machine slips a piece of paper in there first, so the paper gets it. (Again, direct contact, no jumping.) Once again, a little residual toner is left behind on the belt, it isn't a "perfect" transfer" and this also makes it to the waste container.

Toner occasionally gets onto the 2nd BTR roller, too, and it has a brush and a wiper blade to clean itself. The toner it cleans, however, stays inside the cavity of the 2nd BTR assembly. It isn't plumbed to the waste container.

To answer the original question, the developer and toner are mixed in the cartridge and fed together. The ratio of toner to developer is specific, but it can be fed in unevenly (since it is just loosely mixed in the cartridge) but this doesn't cause problems. To avoid developer build up in the developer assembly, a little bit of developer is sloughed off continuously, to the waste container. There is no way for the machine to differentiate between worn developer and new developer, so sometimes it is new stuff that gets dumped, but with a continuous supply coming in, it is still much much longer lasting.

Developer particles don't lose their magnetic properties, though that is commonly believed to be the reason they stop working well. The real reason is that they are very spiky, with lots of points and edges, when they are new. This gives lots of specific points for toner particles to "stick" to. As developer ages, abrasion of constantly going round and round smoothes them out and with fewer sharp edges and spikes, they can't carry as much toner, or as well. Yet they still take just just as much "space" in the dev assembly. Transfer quality is more affected the smoother it gets.

this is why he is an ex xerox employee

[Texiun]

Haha, that's a bizarre, and significantly incorrect, explanation they gave you... The developer never leaves the developer assembly, except as waste to the waste container. Not in a properly operating system, anyway. The developer does indeed "carry" the toner, on a magnetic roll which is part of the developer assembly, and that roll come in close proximity to the drum. The toner being charged one way and the drum being charged another (thanks to being bombarded by the laser) causes the toner to "jump" from the weak grip of the developer on the magnetic roller onto the drum, in those areas which the laser unit charged only, of course. The magnetics of the roll and developer prevent the developer from jumping as well. (Not that it would in a normal situation. Each particle of developer is an order of magnitude heavier than each particle of toner.)

Using Non Genuine Toner is a major Cause for machine parts failing early, (Due to the Toner mixture not being correct for the machine - Incorrect Polarity rates etc, Causes Dev Dumping/Toner Piles)

Once the toner is on the drum, the drum then rotated to come in contact with the accumulator belt

.
Also known as IBT Belt (Intermediate Belt Transfer)

Again, static charges are used to cause the toner to transfer from the drum onto the belt.

This is Done via the 1st BTR (There are 4 of these One for each Color)

(This time they are in direct contact. No jumping.) A little bit of residual toner is left behind on the drum and this is cleaned off by a wiper blade and after a long trek makes its way to the waste container.

The Old Image that has been written onto the Drum from the ROS(Raster Output Scanner) is erased most commonly by Erase lamps (LEDS) Or a Secondary Corona Wire

Once all four colors are collected on the belt, the complete image is then transferred to the paper again with static charges, this time between the belt and the 2nd BTR roller. The 2nd BTR roller is "pulling" the toner towards itself, but the machine slips a piece of paper in there first, so the paper gets it. (Again, direct contact, no jumping.) Once again, a little residual toner is left behind on the belt, it isn't a "perfect" transfer" and this also makes it to the waste container.

To answer the original question, the developer and toner are mixed in the cartridge and fed together. The ratio of toner to developer is specific, but it can be fed in unevenly (since it is just loosely mixed in the cartridge) but this doesn't cause problems. To avoid developer build up in the developer assembly, a little bit of developer is sloughed off continuously, to the waste container. There is no way for the machine to differentiate between worn developer and new developer, so sometimes it is new stuff that gets dumped, but with a continuous supply coming in, it is still much much longer lasting.

Developer particles don't lose their magnetic properties, though that is commonly believed to be the reason they stop working well. The real reason is that they are very spiky, with lots of points and edges, when they are new. This gives lots of specific points for toner particles to "stick" to. As developer ages, abrasion of constantly going round and round smoothes them out and with fewer sharp edges and spikes, they can't carry as much toner, or as well. Yet they still take just just as much "space" in the dev assembly. Transfer quality is more affected the smoother it gets.

The Developer does indeed lose its polarity which causes it to not attach the the Mag Roller, Which results in the Dev Roller not having a uniform layer of Developer on it to carry the toner (Which is why you see Auger Marks in the images some times)

Once you start Seeing Faded PRINTS (Remember there is always a key difference between Copies VS Prints IIT(Image Input Terminal)/IOT (Image Output Terminal) You can start to think Dev, Easiest way is to do a half page of that specific color (CMYK) and you will see wavy patches throughout the image (caused by the Dev Auger - As Explained above)