I provide pre and post sales technical support to Canon Production Print Solutions customers in GA/AL/TN and have 2 current iX customers in my area, along with a 3rd in SC that I've helped out at. Though I do work for Canon I spent 15 years prior in print production running most major digital printers with the exception of the Indigo.
The above listed specification of 4500 4/4 printed 12"x18" sheets per hour for the varioPRINT iX3200 is correct. There is a slower "SpecialtySpeed" setting that is enabled (or not) in each media catalog that on the i300 and i300+ is used to provide extra drying time for some heavy weight and coated papers. So for it hasn't been necessary to enable that speed within any of the 350+ media catalogs available currently for the iX, including some 130lb uncoated cover stocks and 120lb coated cover stocks.
Two things that will eat into the number of printed sheets being produced are any QC sheets printed and any automatic cleaning cycles triggered during a run. By default, a single QC sheet used to detect individual nozzle failures is printed every 100 sheets, though that interval can be changed up or down by the operator depending on a customer's tolerance level for potential jetouts in the prints. In addition, a set of 4 QC sheets used to dynamically correct color uniformity across the print width are printed every 2000 sheets by default. With those QC sheets set to their default intervals you would lose 53 sheets per hour. During continuous running there would also be an automatic purge and wipe of the print heads that would take about 45 seconds every 3.5 hours. Averaged out by hour that would be another 19 sheets.
With multiple paper drawers assigned to the job media in use and a single stacker that ejects a full stack while stacking another, a good operator can keep the printer running continuously. There are only a few things that could stop the printer for maintenance during a run - the one most likely would be to change the tissue wipe cassettes. One other thing that would cut into the productivity would be any sheets of paper with defects bad enough to be rejected by the sentry unit, which is a set of 3D cameras that inspect every sheet for things like nicks, wrinkles, bent edges, etc. that have the potential of striking the heads. New sheets with defects would be rejected individually; a sheet with a defect that has already been printed on one side would force a flush of the entire paper path to maintain job integrity.
Being a former operator I know that some people may not take my words at face value so I would be more than happy to put you in contact with one of the operators in my customers or refer you to one of my counterparts in your area who could do the same.
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