Why laser length limits?

  • Thread starter Thread starter Richard Galli
  • Start date Start date
R

Richard Galli

Here's an amateur question?

Why can't color laser printers use paper lengths longer than (for
example) 17 inches?

The carriage limits the width, of course. But if the carriage is 11"
wide (the printer takes at least 11X17 paper) what is the reason why I
cannot print an image 24" long or longer -- either custom cut or on a
roll? Why can't I print an image 11"X24" instead of just 11"X17" ?

What prevents a laser from printing "banner" images on long paper,
assuming I can get paper packaged or cut to the length I want?


Why can't laser printers do what inkjet printers do?


I need to print images on paper 11" X 24" or on 11" wide rolls. Is there
a quality laser printer that could do it?

Thanks!
 
Richard Galli said:
Here's an amateur question?

Why can't color laser printers use paper lengths longer than (for
example) 17 inches?

The carriage limits the width, of course. But if the carriage is 11"
wide (the printer takes at least 11X17 paper) what is the reason why I
cannot print an image 24" long or longer -- either custom cut or on a
roll? Why can't I print an image 11"X24" instead of just 11"X17" ?

What prevents a laser from printing "banner" images on long paper,
assuming I can get paper packaged or cut to the length I want?


Why can't laser printers do what inkjet printers do?


I need to print images on paper 11" X 24" or on 11" wide rolls. Is there
a quality laser printer that could do it?

Thanks!
Click to expand...

Richard
The issue is that laser printers cannot stop the paper whilst its memory is
being updated. Once the paper starts to move the page has to be completed. So
basically the memory size in a laser determines the maximum amount of data that
can be printed on a page and this in turn affects the maximum length. OKI
colour lasers will print up to1.2 (Ithink) metres in length.
Tony
 
Richard Galli said:
Why can't color laser printers use paper lengths longer than (for
example) 17 inches?
Click to expand...

They can.

http://www.xerox.com/igen3

Other, smaller laser printers can do 13x19.

And then there are the continuous feed laser printers.

It's simply a design decision, that's all.
 
Richard Galli said:
The carriage limits the width, of course. But if the carriage is 11"
wide (the printer takes at least 11X17 paper) what is the reason why I
cannot print an image 24" long or longer -- either custom cut or on a
roll? Why can't I print an image 11"X24" instead of just 11"X17" ?

What prevents a laser from printing "banner" images on long paper,
assuming I can get paper packaged or cut to the length I want?
Click to expand...

Memory, fuser, and a few other things.
 
Tony <?@?.?.invalid> said:
The issue is that laser printers cannot stop the paper whilst its memory is
being updated. Once the paper starts to move the page has to be completed. So
basically the memory size in a laser determines the maximum amount of
data that
can be printed on a page and this in turn affects the maximum length. OKI
colour lasers will print up to1.2 (Ithink) metres in length.
Click to expand...

Does not the circumference of the image drum come into it?
 
[email protected] said:
Does not the circumference of the image drum come into it?
Click to expand...

Not really Timothy, the drum is refreshed in real time by the high voltage
charging process and by the laser or the LED array.
An A4 (portrait) page is refreshed anywhere between 3 and 4 times during the
printing of the page depending on the drum diameter and this equates to 3-4
rotations of the drum.
If a longer page is printed then more refreshes are required.There are
exceptions to this but it is the most common laser printing process. If you
were to gouge a small hole in the surface of a drum you would find this would
manifest itself as 3 or 4 marks on an A4 page, not suggesting you should try
this of course!
Tony
 
Tony <?@?.?.invalid> said:
Not really Timothy, the drum is refreshed in real time by the high voltage
charging process and by the laser or the LED array.
An A4 (portrait) page is refreshed anywhere between 3 and 4 times during the
printing of the page depending on the drum diameter and this equates to 3-4
rotations of the drum.
If a longer page is printed then more refreshes are required.There are
exceptions to this but it is the most common laser printing process.
Click to expand...
And of course, to be awkward I think my machine is one of the
exceptions! For an A4 (c. 12"x8") printer it doesn't need a very large
drum (diameter c. 4") to do it in one go.
If you
were to gouge a small hole in the surface of a drum you would find this would
manifest itself as 3 or 4 marks on an A4 page, not suggesting you should try
this of course!
Click to expand...

Funnily enough, mine has a little spot of dirt somewhere inside it that
causes a little black splot[1] once on an A3 sheet, which means it
appears on every other A4 sheet, I could print at A4-R which would mean
the spot would be off the A4 page but it would reduce speed, or I could
strip the thing down and find it, but at the moment its not worth the
effort.


[1] Highly technical word there
 
There is an Oki Data that apparently can do it, although I am still not
quite clear on how.

To explain as simply as possible, inkjet printers have a small memory
buffer because they only need to be aware of one or two lines of
information at a time, since the head is moving back and forth and the
information is rasterized as an image on the hard drive and slowly
transferred to the printer and printed, line by line.

For most of the laser printers the full sheet's image is transferred as
a printable file to the laser printer's memory, and then the image is
created wit the laser onto a drum or transfer belt while the paper is
moving and the toner is being transferred to the paper and then fused
onto it as heat is applied. That method drastically speeds up the
process, because the data transfer is one of the slower functions. The
engine can print multiple copies from the rasterized full page in memory
quite quickly, while the inkjet printer needs the data to be sent again
line by line or so, for each copy. The mechanics are also quite
complex, so although continuous laser printers exist, they are made in
small quantities and are very costly, relative to others, in general.

Art
 
[email protected] said:
Tony <?@?.?.invalid> said:
Not really Timothy, the drum is refreshed in real time by the high voltage
charging process and by the laser or the LED array.
An A4 (portrait) page is refreshed anywhere between 3 and 4 times during the
printing of the page depending on the drum diameter and this equates to 3-4
rotations of the drum.
If a longer page is printed then more refreshes are required.There are
exceptions to this but it is the most common laser printing process.
Click to expand...
And of course, to be awkward I think my machine is one of the
exceptions! For an A4 (c. 12"x8") printer it doesn't need a very large
drum (diameter c. 4") to do it in one go.
If you
were to gouge a small hole in the surface of a drum you would find this would
manifest itself as 3 or 4 marks on an A4 page, not suggesting you should try
this of course!
Click to expand...

Funnily enough, mine has a little spot of dirt somewhere inside it that
causes a little black splot[1] once on an A3 sheet, which means it
appears on every other A4 sheet, I could print at A4-R which would mean
the spot would be off the A4 page but it would reduce speed, or I could
strip the thing down and find it, but at the moment its not worth the
effort.


[1] Highly technical word there
Click to expand...

Splot is an industry standard word meaning splodge so feel free to use it!!!
Sounds like you have a printer that uses a transfer belt, (this is a relatively
small part of the laser market) and when they put marks on the paper they often
do so in the same place on each page unlike marks from drums and other rollers
which nearly always vary in placement but invariably repeat on the page.
Cleaning a transfer belt can be a delicate operation and can sometimes result
in more damage. On the other hand the blemish can usually be seen by the naked
eye.
Tony
 
As mentioned before the image drum diameter, the bigger the drum the
longer the print.

Imagine paper round a 12 inch diameter drum and paper round a 24"
diameter drum the paper length is twice as long.

Davy
 
As mentioned before the image drum diameter, the bigger the drum the
longer the print.

Imagine paper round a 12 inch diameter drum and paper round a 24"
diameter drum the paper length is twice as long.

Davy
Click to expand...

Strictly speaking Davy that is not quite right, the circumference of drums used
in the majority of Letter or A4 laser printers is between one quarter and one
third of the length of a sheet of paper. There are some lasers with large
diameter drums of course, some Lexmark lasers come to mind and also some colour
lasers.
So the diameter of the drum is not the limiting factor, the most significant
limiting factor is printer memory.
Tony
 
Tonywrote
quote="Tony"
Strictly speaking Davy that is not quite right, the circumference o drums used
in the majority of Letter or A4 laser printers is between on quarter and one
third of the length of a sheet of paper
Click to expand...

Yeah, got that wrong didn't I, thanks Tony for the correction, wa
just trying to explain in the simplist way

Dav
 
If a standard tabloid laser's base memory is upgraded -- say from 256
megs to 512 or 1 gig -- will it be able to print a document 11 X 24
instead of 11 X 17?

Would be nice to know.

Thanks.

rg
 
Richard Galli said:
If a standard tabloid laser's base memory is upgraded -- say from 256
megs to 512 or 1 gig -- will it be able to print a document 11 X 24
instead of 11 X 17?

Would be nice to know.

Thanks.

rg
Click to expand...

Richard
It will depend on the printer model, the engine has to be capable of handling
longer paper and there are several considerations.
For instance at least one of the paper trays has to be able to handle longer
paper, often tray 1 (usually the top multipurpose tray) can do this provided
the paper is supported during feeding. The engine controller must not have
built in length limitations (a design criteria). The driver has to be capable
of handling longer paper. And there are other considerations like the formatter
which converts data into marks on the paper and which controls the printer
engine.
The quick answer is that it probably will not work unless the printer was
originally designed to permit this and the drivers are written to handle it.
You would need to research the issue with the printer manufacturer or supplier.
Tony
 
As mentioned before the image drum diameter, the bigger the drum the
longer the print.

Imagine paper round a 12 inch diameter drum and paper round a 24"
diameter drum the paper length is twice as long.
Click to expand...

If you have a look in the Troubleshooting section of the user manual, or
maybe the service manual, you'll find that there is usually a chart
showing "repeat" marks or blemishes and how far apart on the page they
occur which acts as a guide to the fault. eg x number of mm apart means
the imageing drum, and y number of mm apart means the fuser etc. x or y
(or z etc) is the circumference of the roller object where the problem is
and in almost all cases is much less than the length of the maximum
size of the paper. A big exception is the printers which use a transfer
belt. EG HP colour lasers
 
Back
Top