99% of inkjet cartridges are foam based cartridges and do not leak in to the printer. It is physically impossible for a foam based cartridge to leak as the foam holds the ink and requires the printer to “pull” the ink out.
The ink that you notice in your printer is caused from frequent turning on/off of your printer, cartridge replacement, alignment & automatic cleaning cycles. The cleaning cycles draw ink out of the cartridge to clean the print-head. Overtime, the reservoir (area under the printer which is covered by thick cardboard or foam) gets filled with this ink and needs to be cleaned or the printer will need to be replaced. This happens especially if the printer is turned on and off every day or is a high usage printer. Some Canon printers will literally shut down if this tray gets full.
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