During my ownership of the Canon i9900 whereupon I upgraded the printer firmware from Canon I noticed something after the upgrade. The printer seemed to hesitate more with added head action and priming cycles. Then it occurred to me what was happening.
The firmware upgrade from Canon was deemed to "protect" the head. Well, my hunch is that this protection was mainly due to more priming cycles ( a smaller head cleaning) to ensure that the nozzle reservoirs was always fully loaded to supply the nozzles with the ink required. Furthermore it is my belief is that the high printing speed of the 9900 meant that the nozzles were using ink at a fast rate and that brought the ink delivery system close to the limits of its delivery rate. If cartridges were not in prime condition (near empty for example) or there was printing where most of the nozzles of a color channel were used then reaching or exceeding thelimits could happen. In this case, the reservoir would starve of ink because the ink would not be delivered as fast as it was being used and nozzle degradation due to kogation (burnout) would occur. The only way to recharge the ink reservoir ( a small trough of ink, the length of the nozzle plate just above the nozzles) is to run a prime cycle where the pump would literally pull ink from the cartridge like a head cleaning and recharge the reservoir instantly.
Looking at this situation, it is likely that during the initial design, the engineers did not anticipate certain printing sequences or maybe did not see cartridges with wider variations of ink deleivery rate. Now because in other countries where the ink consumption rate is published, they must also attempt to minimize the ink consumption as well. Thus the programming of the printer may have involved a tradeoff betwen ink consumption with more prime cycles versus ink economy. Maybe the decision leaned too far on the ink economy side and the firmware revision was to correct that decision as feedback through warranty claims and further testing may have revealed or provided more insight into where the balance was more correct.
Please also note that for there is an internal timer on the printers that can sense whether the printers had been used within a certain interval ( usually 24hrs) and if not it will initiate a prime cycle to ensure that the nozzles have not dried out. The Canon service manuals of the printes point out exactly how often a cleaning is performed, how much ink is used and what interval the cleaning occurs. It's not a secret but it is hard to locate that information.
On Epsons, the amount of priming cycles that occur will also depend on the print quality setting used. Highest print quality will entail more primes to ensure that the nozzles are always full of ink.
I am sure that the amount of priming done is one out of necessity due to printer design and engineers simply don't prime for the heck of it. The pros and cons of various head designs just like all things will involve some level of compromise.
The firmware upgrade from Canon was deemed to "protect" the head. Well, my hunch is that this protection was mainly due to more priming cycles ( a smaller head cleaning) to ensure that the nozzle reservoirs was always fully loaded to supply the nozzles with the ink required. Furthermore it is my belief is that the high printing speed of the 9900 meant that the nozzles were using ink at a fast rate and that brought the ink delivery system close to the limits of its delivery rate. If cartridges were not in prime condition (near empty for example) or there was printing where most of the nozzles of a color channel were used then reaching or exceeding thelimits could happen. In this case, the reservoir would starve of ink because the ink would not be delivered as fast as it was being used and nozzle degradation due to kogation (burnout) would occur. The only way to recharge the ink reservoir ( a small trough of ink, the length of the nozzle plate just above the nozzles) is to run a prime cycle where the pump would literally pull ink from the cartridge like a head cleaning and recharge the reservoir instantly.
Looking at this situation, it is likely that during the initial design, the engineers did not anticipate certain printing sequences or maybe did not see cartridges with wider variations of ink deleivery rate. Now because in other countries where the ink consumption rate is published, they must also attempt to minimize the ink consumption as well. Thus the programming of the printer may have involved a tradeoff betwen ink consumption with more prime cycles versus ink economy. Maybe the decision leaned too far on the ink economy side and the firmware revision was to correct that decision as feedback through warranty claims and further testing may have revealed or provided more insight into where the balance was more correct.
Please also note that for there is an internal timer on the printers that can sense whether the printers had been used within a certain interval ( usually 24hrs) and if not it will initiate a prime cycle to ensure that the nozzles have not dried out. The Canon service manuals of the printes point out exactly how often a cleaning is performed, how much ink is used and what interval the cleaning occurs. It's not a secret but it is hard to locate that information.
On Epsons, the amount of priming cycles that occur will also depend on the print quality setting used. Highest print quality will entail more primes to ensure that the nozzles are always full of ink.
I am sure that the amount of priming done is one out of necessity due to printer design and engineers simply don't prime for the heck of it. The pros and cons of various head designs just like all things will involve some level of compromise.
