HP Original Cartridges

Memory

New Printer

LaserJet M604 M605 and M606 printers all come with 512MB RAM (expandable to 1.5GB)

Reliable Remanufactured Cartridges

One of the merits of the P4014 against a new printer is the low cost of good re-manufactured cartridges.

Error Message 21 for HP P4014, P4015 and P4515 Series Printers.

21 PAGE TOO COMPLEX -alternates with "To Continue Press OK" - not enough memory.

Pressing "Go" or "OK" will print the page, but since the data transfer didn't complete it is likely to be imperfect. If this happens often then the print jobs concerned are too complex for the existing printer memory. These printers ship with a large memory: 96Mb on the base model P4014 and 128MB on all others. That may still not be sufficient to deal with (say) a couple of sides of really detailed imagery at 1200 dpi specified in a complex language like PostScript being queued as another print-job prints.

Explanation

Laser printers are a bit unusual in that once the print process starts it cannot stop. A dot matrix or inkjet printer can simply stop after a page-swath whilst more image is made up, but the laser printer mechanism is a succession of rollers that must all turn together holding precise electric fields; it cannot stop and wait whilst a processor creates more material.

To be sure of printing a page correctly the laser printer needs to be able to make up the page-image or framebuffer in memory before it begins to print. Once the print action has begun and all the rollers in the printer are in motion it will not be able to stop.

Printed pages potentially occupy a great deal of memory. Take an 11 x 8 inch image at 1200 dpi; that comes out at 126,720,000 dot-positions and possibly nearly 128 megabytes if those positions allow for greyscale. In practice there is some overlap between greyscale and dither pattern so memory use may not be quite so dramatic. All the P4014 models except the non-network model actually provide 128MB of memory. Since printers use memory compression techniques like run-lengths to minimise the memory footprint a smaller RAM is usually sufficient for both a highly complex page image and several others being constructed for simultaneous network tasks.

However 128MB may not be enough in all cases. If a page is described in a vector language like PostScript or PDF then the description has to be held in memory at the same time as the framebuffer from which the page will print. Furthermore whilst the printer is working out the conversion from PostScript to the bitmap in framebuffer it may still be getting more data from the network. The complexity of a page can exceed the printer's ability.

Quite commonplace things like a checkerboard of alternating black and white dots looking grey overall can have an alarming impact on memory (and waste a lot of toner); forms designers sometimes don't realise that what looks great printed by offset litho is not so good on a digital printer.

Look at the size of the print job in the spooler. If need be reduce the resolution to 300dpi. If it's a form that probably won't even be noticed, if it's a photo it may spoil it - (but mono laser printers aren't really aimed at digital photography) . If this message is happening often then reduce your ambition for graphics or install more memory in the printer.

Remedies

One possibility to make a job print is to reduce the resolution to 600dpi or 300dpi (the control is in the driver). Another is to split the print job into smaller tasks so that a 40 page graphic heavy report is made into 2 x 20-page reports. Yet another is to select a PCL driver instead of Postscript - it often has a smaller memory footprint.   If the error often happens with jobs that must print at high quality then a DIMM unit needs to be installed to extend the printers on-board memory. There is one DIMM slot available on the formatter. See memory devices like the CE483A . HP memory is rather pricey (and often has a lead time because the distributors don't expect to sell it). Third-party memory costs rather less - however we aren't able to advise what may work well.

Note that there is only one DIMM slot and that whilst the memory used by these printers is industry standard it isn't commonplace. Big memory devices such as 512MB are likely to entirely clear up "Error 21", smaller devices may not do so.

The price of HP original memory is actually higher than that of the successor printers. It might cost less to buy a LaserJet 604dn than the memory - it has a more powerful processor as well - but it doesn't take the same cartridges.

Web Research

"21 errors" are not all that common. Querying Google gave About 389 results (0.24 seconds) which is a sizeable but not huge response.

Copyright G & J Huskinson & MindMachine Associates Ltd 2013, 2015. Some pictures derived from HP User and Service guides. These technical pages do not constitute an offer for sale; just our knowledge at the time of writing. See the catalogue. Sales pages on this Web site use cookies to store user information. We also use Google Analytics to track site usage patterns.