[Misc] Can anyone explain the copier process like what type of charge is genrated

[Sahil102]

Helo

Can somone explain me the copier process like what type of charge (positive or negative charge) is generated by corona and what charge is on drum and toner so it attracts each other.
I want to know when would black dots appear from where the drum sparks and where white dots come.

[Phil B.]

Re: Can anyone explain the copier process like what type of charge is genrated

Helo

Can somone explain me the copier process like what type of charge (positive or negative charge) is generated by corona and what charge is on drum and toner so it attracts each other.
I want to know when would black dots appear from where the drum sparks and where white dots come.

Stop posting this problem multiple times

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[Hishamawada]

Re: Can anyone explain the copier process like what type of charge is genrated

Do you have a test you need to take ?

My friend Canon manuals explains everything in details for you .

But u need to know that not all printers work with the same technology.




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[nathicana]

Re: Can anyone explain the copier process like what type of charge is genrated

In section 2 technology of the Canon 8500 series service manual this is explained. The laser writes to the non image areas of a positively charged drum . We would describe that as "Write to white".

If the drum is chipped that machine should represent the chip as a white mark. Maybe someone could test this to verify. It is a good question.

Many other machines write to black so a chipped drum surface would tend to produce black marks.

Canon 8500 series white writer.pdf

I don't think it is 100 percent predictable whether drum surface chips will show as black or white regardless of polarity

[fchu5959]

Re: Can anyone explain the copier process like what type of charge is genrated

Helo

Can someone explain me the copier process like what type of charge (positive or negative charge) is generated by corona and what charge is on drum and toner so it attracts each other.
I want to know when would black dots appear from where the drum sparks and where white dots come.

This is ,in fact, a very good question that most of the Canon trainers skip to answer nowadays because most of them have not got the proper training to explain that.
Yes,Hishamawada is right to say that evrything is explained in the manuals but it is not easy to understand.
It is all a matter of positive and negative charges or attraction and repulsion between like and unlike charges and if the laser "writes" or "erase"(that's the way i learned it from Canon France training camp 25 years back)
So,of course,you can predict the result of a chip on the drum.
To make it simple,if the drum is Amorphous Silicon(which is the case on high speed black and white models),the result will be a white dot.But since you do not have white toner,the white here is the color of the paper.if you want to check it,make a full page black on a yellow paper,the color of the dot will be yellow.In other words,the chip on the drum will not attract toner.
On the other hand,if the drum is OPC(Organic photoconductor),the chip on the drum will result in a black or color dot(on color copiers).

Always remember that,Amorphous silicon drum is charged positively by the corona grid and the laser writes on non image area whereas the OPC drum is negatively charged by the corona grid or primary roller and the laser writes on image areas.

It's always interesting to know and understand the theoretical fundamentals of Xerography but even without that knowledge,you could be a smart tech with experience and common sense.

[BillyCarpenter]

Re: Can anyone explain the copier process like what type of charge is genrated

This is ,in fact, a very good question that most of the Canon trainers skip to answer nowadays because most of them have not got the proper training to explain that.
Yes,Hishamawada is right to say that evrything is explained in the manuals but it is not easy to understand.
It is all a matter of positive and negative charges or attraction and repulsion between like and unlike charges and if the laser "writes" or "erase"(that's the way i learned it from Canon France training camp 25 years back)
So,of course,you can predict the result of a chip on the drum.
To make it simple,if the drum is Amorphous Silicon(which is the case on high speed black and white models),the result will be a white dot.But since you do not have white toner,the white here is the color of the paper.if you want to check it,make a full page black on a yellow paper,the color of the dot will be yellow.In other words,the chip on the drum will not attract toner.
On the other hand,if the drum is OPC(Organic photoconductor),the chip on the drum will result in a black or color dot(on color copiers).

Always remember that,Amorphous silicon drum is charged positively by the corona grid and the laser writes on non image area whereas the OPC drum is negatively charged by the corona grid or primary roller and the laser writes on image areas.

It's always interesting to know and understand the theoretical fundamentals of Xerography but even without that knowledge,you could be a smart tech with experience and common sense.

Very good. Too many people fail to learn what I consider to be foundational knowledge. A house can't stand if it doesn't have a strong foundation.

[nathicana]

Re: Can anyone explain the copier process like what type of charge is genrated

This is ,in fact, a very good question that most of the Canon trainers skip to answer nowadays because most of them have not got the proper training to explain that.
Yes,Hishamawada is right to say that evrything is explained in the manuals but it is not easy to understand.
It is all a matter of positive and negative charges or attraction and repulsion between like and unlike charges and if the laser "writes" or "erase"(that's the way i learned it from Canon France training camp 25 years back)
So,of course,you can predict the result of a chip on the drum.
To make it simple,if the drum is Amorphous Silicon(which is the case on high speed black and white models),the result will be a white dot.But since you do not have white toner,the white here is the color of the paper.if you want to check it,make a full page black on a yellow paper,the color of the dot will be yellow.In other words,the chip on the drum will not attract toner.
On the other hand,if the drum is OPC(Organic photoconductor),the chip on the drum will result in a black or color dot(on color copiers).

Always remember that,Amorphous silicon drum is charged positively by the corona grid and the laser writes on non image area whereas the OPC drum is negatively charged by the corona grid or primary roller and the laser writes on image areas.

It's always interesting to know and understand the theoretical fundamentals of Xerography but even without that knowledge,you could be a smart tech with experience and common sense.

What you say may be true of Canons and I realize this is a Canon thread. Most of what you wrote is not a rule though.

OPC drums are not always negatively charged as you can read on this page from the Kyocera M2535dn service manual.

OPC positive charged.pdf

Drum chips can show as image or non image depending on circumstances. This is shown on these two prints from the very same machine, an M2535dn.

Black and White marks.pdf

Though it may be uncommon plenty of machines have written to the image areas of Amorphous Silicon drums, why wouldn't they be able to? An example would be the Kyocera 820.

[anothertech]

Re: Can anyone explain the copier process like what type of charge is genrated

Very good. Too many people fail to learn what I consider to be foundational knowledge. A house can't stand if it doesn't have a strong foundation.

I can never seem to remember what charge is on the drum or if you block the slit glass will it be white or black on the paper. I don't think remembering all of that is necessary to service MFP's these days. Day to day problems are pretty straightforward and when I do run into a difficult problem, I can just look it up at that time. There are just too many variables to try to remember.

[ReproKev]

Re: Can anyone explain the copier process like what type of charge is genrated

You can also get black "pepper spots" across the page (looks like someone sprinkled pepper on the paper) on those same Canon high speed copiers with the ASI duums. That comes from not replacing the primary charge wires. If you let it go long enough, the primary corona will arc to the drum, permanently damaging the ASI surface and causing the white spots in the black image areas.

[copier tech]

Re: Can anyone explain the copier process like what type of charge is genrated

Helo

Can somone explain me the copier process like what type of charge (positive or negative charge) is generated by corona and what charge is on drum and toner so it attracts each other.
I want to know when would black dots appear from where the drum sparks and where white dots come.

Read the service manual for your unknown machine

[BillyCarpenter]

Re: Can anyone explain the copier process like what type of charge is genrated

I can never seem to remember what charge is on the drum or if you block the slit glass will it be white or black on the paper. I don't think remembering all of that is necessary to service MFP's these days. Day to day problems are pretty straightforward and when I do run into a difficult problem, I can just look it up at that time. There are just too many variables to try to remember.

That method works, too. Years ago an old wise electronics tech asked me why I was memorizing so much information. He went on to say that he preferred to use his brain to think and not to store a bunch of data and said that if he needs to know something that the information was at his fingertips.

[Hishamawada]

Re: Can anyone explain the copier process like what type of charge is genrated

Most techs I see works in a trial and test method . They try something here , someting there until they solve the issue . And this is the wrong way to service any printer it could be .

First thing is that you need to understand how everything works in the printer, its technology , mechanism , control .... Everything but never need to memorize anything , since it all there in the manual u can always return and read again .

My experience in working on production printers and sometimes I get to face issues that are not common and it is not a matter of changing parts and testing . It could be a small adjustment mechanically or a value in the service mode . These cases where your knowledge will help .

Getting back to the point were talking about . Some machines get there drum positive and the toner in negative and some are vise versa. Some printers works on the difference of the value , ex +1000mv drum charge and ,200v for toner and this way they also got attracted. (Not sure which should be larger ). oce dp line doesn't have laser nor corona , its drum have around 6000 tracks to draw the image directly .



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[fchu5959]

Re: Can anyone explain the copier process like what type of charge is genrated

What you say may be true of Canons and I realize this is a Canon thread. Most of what you wrote is not a rule though.

OPC drums are not always negatively charged as you can read on this page from the Kyocera M2535dn service manual.

[ATTACH]50228[/ATTACH]

Drum chips can show as image or non image depending on circumstances. This is shown on these two prints from the very same machine, an M2535dn.

[ATTACH]50229[/ATTACH]

Though it may be uncommon plenty of machines have written to the image areas of Amorphous Silicon drums, why wouldn't they be able to? An example would be the Kyocera 820.

i have no doubt about what you write about the technology Kyoceera uses in his MFP.;but, Canon uses a different technology and applies it to all its range of MFP including production image press such as C10000 vp.So let us stick to Canon since 'as you say,this is a Canon thread.

[Drivee]

Re: Can anyone explain the copier process like what type of charge is genrated

Charge on OPC?

All printers which have PCR will charge OPC with negative charge and printers with corona wire will charge OPC with positive charge. The laser will do oposite always. I am not sure if this is answer for your question..

[Vincent128]

Re: Can anyone explain the copier process like what type of charge is genrated

New manuals and instructors do not explain things anymore - why waste time and manual space on people that don't really care to know/troubleshoot/think/understand.

There are those out there that still seek knowledge that is no longer taught.

When was the last time you went to a class and they drew out on the chalk/white board how dithering works or charted out how MMR works ?
Schools used to be 2 weeks and they were HARD, you went over EVERYTHING.

I like to have my new techs read OLD manuals that actually explain shit.
Currently I am using the Toshiba ES6530 but I am sure there is still better explanations of the processes going on in the copier.
Also pre-knowledge of how electrons whizz and how electronical do-dads work and what magic smoke does is required to understand the source materials.

I would be happy to accept any training materials or manuals to use as future training materials.