HP OJ Pro 7740 set up to use black ink only still depletes color cartridges

[SPS_Jay]

I have an Officejet Pro 7740 printer that is set up to use Black Ink only.  The printer is connected to via a home network.  Despite these settings, the printer continues to deplete new color cartridges in a short period of time.   To set up as black ink only, I went to Settings -> Devices and Printers -> HP Officejet Pro 7740 -> Manage -> Printing Preferences -> then selected the "Paper/Quality" tab, under "Print in greyscale" I selected "Black Ink Only".   Despite printing no more than 1000 pages with 99% + printed with black ink only, my color cartridges have run out of ink in less than 6 months.  

Is there another setting, or a different way to set up this printer so it uses less color ink?  

Thanks in advance for your guidance.

[Bob_Headrick · Accepted solution]

The document here describes how ink is used.  Some ink is used for servicing before, during and after each print job.  Even when printing black only the printhead (which has both the black and color nozzles) is waving around in the open air.  Servicing is needed to prevent the nozzles from clogging.

There are some things that can be done to minimize ink usage due to servicing:

• Always leave the printer connected to a live outlet.  Do not use an external power switch to power off the printer.  If the printer is powered off with an external switch more ink is used in the startup process whenever the printer is turned back on.
• I would suggest leaving the printer turned on and allow it to go to sleep.  This will put the printer in a very low power standby mode which will minimize the startup servicing required.

[SPS_Jay]

Bob,

Thanks for the reply.  I let the printer go to sleep and rarely power it down, and when I do I use the power button on the front panel.  I suppose that I am just surprised at the rate of color ink that is consumed for servicing.  I probably print no more than 10-12 color pages per month and I have to replace the color cartridges every 6 months.   That is no more than 150 color pages from cartridges that claim ~700 page capacity.    It sounds like this is how HP has programmed this printer and that there is not much I can do to alter the rate of consumption.   Thanks!