Collation described

In printing, the term Collate refers to the arranging of individual sheets into a pre-determined sequence.  

For example, a perfect bound book needs its pages to be collated in numerical order before it can be bound. 

If you have a 3 page job and want to print 3 copies of that job there are two basic ways to do this: collated and uncollated.

(You can skip to the diagram below)

As shown below, a collated job will print the entire job in numerical order until all pages of that job are complete, and then start the next copy over from page 1 again.  An uncollated job will print the requested number of copies of the first page, and then move on to the next page.

Calculating the number of pages you can collate.

The Aspen system architecture has the RIP delivering pages in RAM to the Durango spooler.  The Durango spooler fills it's Page Pool (RAM buffer) and, from there, delivers it to the printhead controller system.

Collated jobs need to fit entirely within the Durango Page Pool. On a 1-Aspen system it is straightforward to calculate because there will only be one computer.   On a multiple Aspen system you need to figure total RAM across all the RIP computers in order to calculate how many pages your system is capable of collating. 

At 1375x1600 dpi resolution Aspen pages fit ten (10) A4 or Letter pages per gigabyte of RAM.  

Each RIP computer needs 8gb of its own RAM for the RIP, the OS, etc. You can configure the Durango Page Pool to use the remainder of the RAM available on a computer.  

The calculation to figure number of Letter-size pages your system can collate is [ ((RAM in GB) - 8) x (# of RIPcomputers)  10 ]

Therefore a 1-Aspen configuration with 16gb of RAM can collate (16-8)x1x10 = 80 pages.

Therefore a 4-Aspen configuration (as of Nov., 2015, configured with 4 computers) with 16gb of RAM can collate (16-8)x4x10 = 320 pages.

To collate more pages, add RAM and configure the Durango Page Pool accordingly.

Converting for other page dimensions

What about a different size page?  For example, if you want to print short run paperback books.

The calculation is easily alterable for physical dimensions.  It scales up and down linearly.

For example, mass market paperbacks measuring 110×178 mm or 4.4" x 7" or alternate sized "B-format" paperbacks measuring 130mm×198mm or 5.12"×7.8" will fit about 20 pages per gigabyte.  They are about half of a letter page so twice as many will fit in RAM.

The calculation for paperback books is therefore:

[ ((RAM in GB) - 8) x (# of RIPcomputers)  20 ]

Converting for other resolutions

page size resolution pages / GB
8.5"x11" or A4 1375x1600 10
8.5"x11" or A4 1135x1600 12
8.5"x11" or A4 725x1600 19
8.5"x11" or A4 555x1600 25

Changing the Durango Page Pool

In the Durango spooler application, click "configure"

That will bring up a window like this:

You have to stop the spooler in order to change the Page Pool size.  The Page Pool is measured in MB. 4096MB is 4GB.  The current setting of 4096 will give us a collate count of 40 Letter or A4 pages.  

When the spooler is stopped you can edit the Page Pool size.

The new setting will take place after you click "start spooler".  8192MB/8GB will give us a collate count of 80 A4 or Letter pages.

Configuring the system to collate more pages

As of this writing, our computers ship with 16GB of RAM.

32GB of additional RAM will allow you to collate 400 Letter sized pages.

You would have 48GB of RAM in the computer and could allocate 40Gb to the Durango Page Pool.

On a 1-Aspen system that would allow you to collate jobs of 400 pages.

On a 4-Aspen system that would allow you to collate jobs of 1600 pages.

64GB of additional RAM will allow you to collate 720 Letter sized pages.

You would have 80GB of RAM in the computer and could allocate 72Gb to the Durango Page Pool.

On a 1-Aspen system that would allow you to collate jobs of 720 pages.

On a 4-Aspen system that would allow you to collate jobs of 2880 pages.

While we have never done this, in theory you can install 128GB of total RAM in each computer.

This would allow a current theoretical maximum collation of 1200 Letter sized pages on a 1-Aspen press and 4800 pages on a 4-Aspen press.

The computers we ship as of Nov., 2015 come with 16GB RAM and are capable of holding 128GB of RAM.  Check with Xitron if you suspect our computer specification has changed.

 November 17, 2015.

Appendix.  "Old" Collate

Warning.  Not recommended for anyone other than press manufacturers.

Before we moved the collate system into RAM, collate worked like this:

We used postscript commands to repeat the job over and over again until the requested copy count had been satisfied.

This means that there was no page count limitation at all.  However, it also means that we ripped the job over and over again and risked not being able to keep up with the speed of the press, causing job underrun errors. 

For comparision:

Old Collate: RIPs each job one time for every copy count requested, going through each job from start to finish again and again.  No limitation on pages, but a possibility for job underrun errors.

Collate:  RIPs each job one time only and stores it in RAM, sending it to the printhead as many times as the copy count requires.  The page count is limited to what can fit in RAM.  There is no possibility for underrun errors.  

If you know how to edit the Navigator Server .ini file you can enable "old collate".

This setting controls whether or not we manage the collate option by repeating to RIP using PS or whether we handle it in RAM.  To manage the collate option with postscript commands, set CollateInPS value to 1, otherwise leave it as zero or delete the option to collate in RAM

In the Server .ini file