h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

http://www.bbc.co.uk/h2g2/guide/A454547

by jecook (he's been away for a while - I know) so, if there is much to add or correct, it's probably going to be problematic.

I think this entry is quite complete and does not need too much retouching. That's why I recommended this to the PR.

HELL

Hell - that's good.

Is there a word missing here?

The paper is then passed TO|THROUGH a fixing or fusing unit that bonds the particles....


How does the paper feed ensure that only one sheet of paper gets picked (he asks, although he has a brother at Xerox who holds some patents in this kind of thing)?

Hey Ausnahmsweise,

That is probably one of the greatest mysteries of the Universe.

As far as I remember the paperpicking is done by a very carefully adjusted rubber-roll blackbox-apparatus labelled "Don't even try to understand this, otherwise it will stop working."

Sorry cannot help more. Anyways: It's presumably out of the entry's scope, methinks. And as for the word missings - That's probably only gonna get fixed in the Sub-Editing process.

Cheers,

HELL

Nice find Hell - I like it

I seem to remember a load of old HP printers at work that stopped picking up any sheets at all after a while but one could fix this problem by roughening the rubber rollers gently with an emery board. I suspect its a finely balanced mixture of grip of the rubber versus grip of the individual pages to each other

Hey Hell,

That's true - paper handling is out of the scope of the entry. It concentrates on the laser printing process. And it does that well.

Awu.
P.S. Vacuum is one way of picking up exactly one (ie not zero and not more) sheets of paper. Unless they stick together.

awu: Which they always do.

A very fine and clear description of the laser printing process - although there might be some work to do (maybe the editors can do that): e.g. formatting (headers and such). My main concern is the first person used in the intro paragraph which probably should be changed into third person.

But nevertheless a very nice article!

Michael

Hmm, is there anyone around who knows how single paper feeds actually do work (in case they do)? This would make a really interesting topic for an article

Michael

I think that replacing the first paragraph:

"If you have ever wondered how a laser printer operates then this is the article to look at. In this article I shall discus both the theoretical and operational aspects of a "modern" monochrome (black and white) laser printer."

By:

"For those who ever wondered how a laser printer operates this is the article to look at. In this article both the theoretical and operational aspects of a "modern" monochrome (black and white) laser printer shall be discussed."

Should be no problem at all.

Cheers,
HELL

Yes, that's exacty what I would have suggested and it should not be a problem to change this in the editing process.

Michael

Single Paper-feed:

It was not a cheap solution! My HP Inkjet uses a carefully calibrated rubber roll to 'take' the paper. To help the paper stack is inclined at the back... Like this:


--------------------------- <- This is the top paper sheet
--------------------------
------------------------
-----------------------

Also there is a 'dam'(I) on the end of the inclined pile. Like this:


--------------------------
------------------------
--------------------- I
--------------------- I
--------------------- I

The first Inkjet printers required manual single sheet feeding. It was indeed a big problem.

Using 'fresh, dry, non-sticking' paper helps. Other sorts of paper (e.g. glossy paper, transparencies etc.) commonly stick together and jam the printer. - *This* problem is not yet completely solved.

Some other 'uncommon' methods to feed single sheets (not widely used in computer printers, but in offset printers):

1 - Presorting sheets:

-------------------- <--- Sheets
____ <--- Separator (plastic, metal)
--------------------
____
--------------------
____
--------------------


2 - Vacuum cups

3 - Ventilators
- perpendicular to the pile:
ventilator + inclined paper-pile = desired effect

- horizontal to the pile:
makes the pile fluffy and easier to pick by the vacuum cups or rubber rolls.

............................


Enough. Bye,

HELL

Ah yes! I wish my HP Deskjet (jet, not laser) had such a single paper feed The manual says so, but the device keeps sucking in the *whole* pile of paper. Err... it *kept* doing so before it completely gave in and went to the Valhalla of printers.

Back on topic... is it true that Laser printers use up the same amount of toner per copy, regardless of how many black pixels they have to leave on the paper?

ceterum censeo: into the Guide with it!

Bossel

into the guide - when the author removes the first person references - or will the Subs do that for him/her?

Ad

Bossel,

I asked an engineer at Xerox in Rochester, NY.
He said that the developer only supplies the toner that's needed - so the toner used is in direct relationship to the amount of black in the copy. Shades of grey are acheived with fewer black dots, just like in newsprint. On the average text page about 7% of the surface is black.

Awu

Oh, thanks for that
The copy machine in my previous office was obviously of a different type: it had a second container for 'used' toner, and it would fill just as fast as the 'new' toner container got empty!

Editorial Note: This conversation has been moved from 'Peer Review' to 'How a Laser Printer operates'.

This thread has been moved out of the Peer Review Forum because your entry has now been recommended for the Edited Guide.

You can find out what will happen to your entry here: http://www.h2g2.com/SubEditors-Process

Congratulations!

Hi just poped in to say I submitted you entry for inclusion, and it has now been passed on to the subeditors.

Heh. Quite a while I think.

Fortunatly I remembered my password...

I'll clear up the thing about the roller now. I can bash out several articles on this vein once I get rolling...

The roller is made of soft rubber. It grips the page, and keeps from grabbing multiple pages via a seperation pad/roller (depending on the printer make or model).

When this rubber gets old or worn, it gets shiny (or hard), and will refuse to grab paper (paper not feeding jams), or if it is the seperation pad that wears out, it will try to grab the entire stack. This is either easy to fix or bloody near impossible, depending on the printer model and or brand. A temporary fix is use a cassette capstan roller cleaner . (Sometimes it's also labeled rubber rejuvinator.) It will get you going for a bit. If the pad is worn out though, it will have to be replaced. Examples of "hard" ones to fix are the HP LaserJet, the LaserJet II/III. "Personal" laser printers such as the LaserJet 4L, 5L, 6L, the LaserJet 3100 MFD (Multi-Function Device) are also hard ones to fix. "Easy" ones are the LaserJet 4,5, and any of the higher volume ones.


Specific for the Deskjets:
These printers use between three and five rollers. Use the cassette cleaner on them. If it does not work, I'd replace the printer at that point. Inkjet printers are pretty much disposable.

Additional edits:

Awu, I did indeed drop a word. 'TO' should be inserted there. and you are right on the money with the toner coverage.

::groans inwardly:: My brain moves faster then my fingers, I'm afraid.

Hell, the edit to the first paragraph is GREAT.

Bossel, the higer volume machines (including the "almost coffin sized" units) are based more on copiers, which use that method of toner disposal. HP, Lexmark, Okidata, Epson, and Brother integrate the toner disposal into the toner cartridge. Copier machines use the two bin process exclusively, I think (correct me if I'm wrong).

Yes, my Deskjet has been disposed of now. The only thing it does is to slam the printhead with full speed onto the other side and then start a lightshow with its LEDs. I won't buy HP printers any more, not only because of the external transformator which constantly produces heat because the power switch is located *after* the trafo.

Oh, and welcome back Nice to see Rupert/blackout/Nowhere2go2 victims returning

It's good to be back.

Epson makes a decent inkjet printer.

I've seen what they are capable off, and for the most part, they are decent printers that can produce stunning output.

There is one quirk, however: if you don't use them, the ink in the head will dry out, and that can get expensive to fix.

Epson uses a seperate head and tank system on their printers.