Some older model HPPCL printers have a limit of 16 fonts per page. If you send a page that contains more than 16 fonts to an HPPCL printer, a warning message appears.
An Error 20 message might appear on the front panel of the HPPCL printer when printing a document that contains soft fonts. This also indicates that you tried to download more fonts than the printer's memory can hold. You can recover from this error by pressing the Continue button on the printer control panel. The soft font that caused the error is not downloaded and will not print.
To avoid this error, reduce the number of fonts that you try to download, or add more memory to your printer. Also make sure you haven't downloaded any permanent soft fonts that are taking up memory in the printer.