Anyone care to quickly explain a thing?

[Guest]

Hi, I'm a curious enduser looking for a wee explanation if anyone's got the time! What exactly does developer do? I know how to do basic troubleshooting on the printers in terms of deletions and repeating marks and so on, which now and again requires delving into dev tanks to remove a piece of grit or plastic from the mag rollers, but have never been able to find a good explanation of what the developer actually does.

I understand the basic principle of the process my machine uses (drum is charged, laser hits drum selectively, those bits pick up toner from the dev tank, image(s) transferred to IBT Belt from drum(s), image transferred to paper from IBT Belt, fused, paper jam, dammit, why always me, take the finisher off, set up cardboard box catch tray, kick machine) I've heard it's something to do with toner sticking to it - does it end up on the page? If not, at what point and how is it separated from the toner? Does it not have same electrostatic properties? My xerox has trickle charge developer (some mixed into each new toner cart) and I read something on here about 'used' developer being lighter, floating to the top of the dev tank and being sloughed off to the waste toner... so I guess I kinda understand how it can be continually replaced now.

Nevertheless - what does the developer do? Why does it 'wear out'?

[Eric1968]

Re: Anyone care to quickly explain a thing?

Developer is used to transfer toner to the drum. Toner particles adhere to developer particles. Toner transfers to the drum, developer stays in the developer unit. After a while the developer wears out, toner particles will not adhere to the developer particles, and you have to replace the developer.

[c.c]

Re: Anyone care to quickly explain a thing?

Cool, thanks Eric! That's been bugging me on and off for a while

[blackcat4866]

Re: Anyone care to quickly explain a thing?

Developer is used to transfer toner to the drum. Toner particles adhere to developer particles. Toner transfers to the drum, developer stays in the developer unit. After a while the developer wears out, toner particles will not adhere to the developer particles, and you have to replace the developer.

Just to expand a little on Eric's explanation:

Each ferrite particle (or developer particle) has a resin coating. When these ferrite particles are agitated, rubbing against each other, they produce the "triboelectric effect" (aka static electricity). This static charge attracts a layer of toner particles around each ferrite particle. As the toner particles are consumed, they are replenished from the toner supply to maintain the same balance/ratio of toner to developer.

Developer wears out in two ways. The resin coating wears off the individual ferrite particles, producing a weaker triboelectric effect. When the triboelectric effect becomes weaker, ferrite particles are pulled from the developing unit, causing an imbalance in the toner to developer ratio. Too much toner means too dark. Too little toner means too light. It can go either way.

The latest technology has taken an interesting twist. To extend the life of the developer, several manufacturers have started adding small amounts of ferrite to the toner cartridge. So as toner is replenished, the developer is enriched.

Does that help? =^..^=

[mojorolla]

Re: Anyone care to quickly explain a thing?

I refer to developer as "carrier" because that is what it does.

[sdrawkcab]

Re: Anyone care to quickly explain a thing?

Just to expand a little on Eric's explanation:

Each ferrite particle (or developer particle) has a resin coating. When these ferrite particles are agitated, rubbing against each other, they produce the "triboelectric effect" (aka static electricity). This static charge attracts a layer of toner particles around each ferrite particle. As the toner particles are consumed, they are replenished from the toner supply to maintain the same balance/ratio of toner to developer.

Developer wears out in two ways. The resin coating wears off the individual ferrite particles, producing a weaker triboelectric effect. When the triboelectric effect becomes weaker, ferrite particles are pulled from the developing unit, causing an imbalance in the toner to developer ratio. Too much toner means too dark. Too little toner means too light. It can go either way.

The latest technology has taken an interesting twist. To extend the life of the developer, several manufacturers have started adding small amounts of ferrite to the toner cartridge. So as toner is replenished, the developer is enriched.

Does that help? =^..^=

Great, now my version of little people inside the copier writing on the paper as it goes thru looks stupid.

[c.c]

Re: Anyone care to quickly explain a thing?

Fascinating stuff Blackcat, I love understanding the workings of the technology around me (there's so much of it these days too). That explains why it's a mag roller in the dev tank.

Does the dev just make it easier to meter the toner evenly onto the drum or are there other reasons that it's used instead of just toner? How long have machines been using developer and toner? I'd never even heard of liquid toner machines before I came on this site... they sounded like pigs.


One semi-interesting fact for you guys, we run a DC260 and a DCP700 - that's EA-HG and EA-ECO toner respectively, but they use the same developer material (I found that out when I was asking why there isn't a set for each machine in our spares box). Surprisingly efficient for Xerox..

[zed255]

Re: Anyone care to quickly explain a thing?

There exist both 'dual component' and 'mono component' systems, the former using developer and toner, the latter just toner. I think there are advantages and disadvantages to each system, though most of my personal experience lies with dual component systems.

The developer itself is generally of similar composition from one machine to the next. Main differences would be particle size and the type of resin used. For different operating speeds and machine types the resin and toner are paired up to give the desired amount and polarity of charge. This is why one can't just put any toner in a machine and have it work as expected.

[blackcat4866]

Re: Anyone care to quickly explain a thing?

Fascinating stuff Blackcat, I love understanding the workings of the technology around me (there's so much of it these days too). That explains why it's a mag roller in the dev tank.

Does the dev just make it easier to meter the toner evenly onto the drum or are there other reasons that it's used instead of just toner? How long have machines been using developer and toner? I'd never even heard of liquid toner machines before I came on this site... they sounded like pigs.


One semi-interesting fact for you guys, we run a DC260 and a DCP700 - that's EA-HG and EA-ECO toner respectively, but they use the same developer material (I found that out when I was asking why there isn't a set for each machine in our spares box). Surprisingly efficient for Xerox..

Like he said.
The toner itself has only charge properties, but the ferrite has magnetic and charge properties. So the ferrite sticks to the mag (magnetic) roller and the toner sticks to the ferrite, via electrical charge.

There is also the developing bias voltages. An AC voltage is applied to the mag roller to propel the toner towards the charged areas of the drum. A DC voltage is also applied to provide an adjustment to how much toner sticks. Think of it like throwing mashed potatoes at a wall. The harder you throw it, the more sticks.

Monocomponent and dual component toner systems are very similar. The difference is that in monocomponent systems the carrier is not ferrite, it's a polymer with magnetic and charge properties that is completely consumed in the developing process. The benefit to monocomponent toner is that there is no balance/ratio to maintain. It's all consumed. Typically monocomponent toner systems run considerably cleaner than dual component and never needs changing or refreshing. The benefit to dual component systems is it produces a darker or richer black. You'll also find that there are very few monocomponent color copiers. I understand it's very difficult to manufacture, and the color is not as vivid.

Another thing that makes a difference is if your machine recycles toner. Toner left over from the copy process can be dumped in a waste container or put back into the developer and reused. The benefit to recycling is better efficiency-more of the toner makes it to the paper. The benefit to not recycling is that paper dust and other contaminants are not sent to the developing unit, extending developer life. Since the color toner cannot be separated back out into the four colors, it's not possible to recycle color toner. =^..^=

[ddude]

Re: Anyone care to quickly explain a thing?

Just to jump in to this discussion, because I can-

Developer is a carrier, like mojorolla stated- the developer carries the toner particles from the source to the drum for imaging. Think of the drum as the camera film, and the toner as the 'print' on the drum, and the developer is the applicator. There has to be precision to place the toner onto the drum without overdoing it, and without under-performing. This is why each machine has a unique blend of developer and toner engineered to fit the precise machine. The wrong blend would cause smudging, or light copies, or black spots on copies, or a host of other problems.
As the machine produces copies, the developer is subjected to a constant churning, along with an applied charge, to create the static needed to 'carry' the toner through the unit, onto the magnetic roller, where a stronger charge (placed onto the drum by a laserbeam of light 'writing' the image on the drum(camera film)) will cause the toner to release from the developer and cling to the drum to form the print.

This is just a quick overview.....

The development phase is just a small portion of the total Xerographic process- there are other important steps, like applying an electrical charge to the paper that is stronger than the drum charge, so the toner will leave the drum (uniformly and without complaint) and stick to the paper, then removing that charge so the paper will separate from the drum, without disturbing the image on the paper, and then, the toner (the 'developed image' from the drum) that is on the paper needs to be fused into the paper,without smearing or tearing or wrinkling, etc.


This process is quite complicated, which is why we technicians earn the big bucks- we are employed to keep everything running smoothly behind the curtain so all you see is blank paper in, printed page out.......no muss, no fuss!!

[TonerMunkeh]

Re: Anyone care to quickly explain a thing?

This process is quite complicated, which is why we technicians earn the big bucks!

Jesus who do you work for?

[prntrfxr]

Re: Anyone care to quickly explain a thing?

Some of the questions I was asked when teaching others about it was:

How big is the developer versus the toner? What is the shape of the particles?
Toner is very small in comparison and in some cases is shaped specifically to enhance print quality.



For more info, check out these links:

http://en.wikipedia.org/wiki/Toner
http://www.ehow.com/facts_7636719_copier-developer.html
http://en.wikipedia.org/wiki/Laser_p...ocopiers Work"[/URL]

[c.c]

[prntrfxr]

I think when I first learned the xerographic process I was amazed too. I remember coming home and used the big eraseable marker board at home in the hallway to explain it to my mom. I had pictures and everything. The more I explained it the more excited I got and faster I was talking. You'd thought I found the cure for cancer or something. But the time I got to the fuser I was bouncing up and down. They're still my favorite part to teach. She just kept laughing at me all the way through. I soon found out later most people could care less. As for the charges the transfer ones are stronger than the drum ones, but remember they are always opposing the charges of the toner. Most toner gets transferred but some doesn't, which is why there has to be a cleaning process. If you really want to learn something, get a service manual. Most manuals have a theory of operation section that explains the process for that machine. Every machine does things a bit differently but the process is still the same. I used to take a service manual and read it at lunch. Understanding how it works makes fixing them a lot easier. Beats spending all day throwing parts at the machine.

-- Sent from my Palm Pre using Forums

[blackcat4866]

Re: Anyone care to quickly explain a thing?

So:

• It's 'weakly' charged and that picks up the toner.
• It's ferrous and that's why the mag roller can pick up the developer.
• It's constantly being agitated which keeps distribution of toner/dev relatively even
* Sometimes old dev is sloughed off and replaced by new material mixed in the toner
* Not all printer's use it, there's pros and cons to each method
* Sometimes it's used in a toner-recycling system

Excellent synopsis.

Hmm, this is getting away from dev a bit now, but my printer has -

Developer Mag Roller
Drum
IBT Belt
Paper

Does the charge get more and more at each stage to make sure the toner transfers?

A lot of this depends on the model. For example some high speed Canon's used a pre-transfer corona unit, to lessen the charge holding the toner, for more effective transfer and less waste. But generally as a rule, yes. At each stage a progressively larger charge is used to attract or repel the toner as needed. Astute of you to notice.

I'm starting to be even more amazed these machines work at all...

I feel exactly the same way. =^..^=