A definition of the AID function from the Epson specs...
"Epson's AID technology uses a sensor near the print head that counts the electrical charges on the ink droplets as they are fired. A lower than expected electrical charge means insufficient ink was fired, so the print head cleaning process starts automatically".
Automatic Nozzle Verification and Cleaning
•Embedded sensors quickly verify nozzle status without using media
•System automatically performs a head cleaning if required
•Nozzle verification is performed in under 30 seconds
•Nozzle verification process consumes less than 1 ml of ink
•Can be set to automatically perform check before each job; periodically;
or can be turned off.
This is from an article I looked up which is part of press release when the 7900/9900 series was introduced 3 years ago.
Epson has since added more choices to the cleaning routine via firmware
Depending on your settings for Auto Clean selected, there are a number of possible scenerios that will take place
This new firmware update is the 4th one that specifically mentions the phrase,
"This update adds improved AID (Auto Ink Detection) functionality.’'
Seems to me there is still an issue taking place with these machines that Epson is very much aware of and is trying to fix through firmware updates.
Apparrently there is still tweaking of this feature going on and it might mean that ink flow in the nozzles are still being misreported and unnecessary cleanings being done wasting ink.
A couple of articles I was able to find pertaining to the issue.
first one by member Wayne Fox.
http://cwaynefox.com/myBlog/Printing/Entries/2009/10/16_New_firmware_for_epson_79_9900_printers.htmlhttp://www.epson.co.uk/Printers-and-All-In-Ones/Large-Format/Epson-Stylus-Pro-7900/Drivers-Support?target=article&extn=.html&articleId=3804Latest update-
The firmware version reported at the printer’s control panel following this update will be: HN028B7,2.10, A000
Firmware version HN01108170 release notes:
19) Improved AID (Auto Ink Detection) functionality.
Previous updates also included in the above:
18) Improves wake from sleep operations.
17) Resolves SpectroProofer issue with page cut prior to printing verification ticket.
16) The WSD function is added to the Network menu in the printer’s control panel.
15) Improved AID (Auto Ink Detection) functionality.
14) Corrects issue with potential printer port lock up when canceling a print job.
13) Improved AID (Auto Ink Detection) functionality.
12) Overall improved printer functionality.
11) Resolves issue when auto head alignment adjustments are repeated multiple times. Following this firmware update users should perform both uni- and bi-d all auto head alignments.
10) The AID (Automatic Ink Detection) system operation has been improved.
9) Network interface support is improved with this firmware version.
8 ) Resolves front panel paper selections that were not stored after printer restart.
7) Ensures proper print head initialization (vibration) prior to start of print.
6) New Control Panel function added enabling automatic black ink switching.
5) Removes automatic nozzle check from the printers power-on sequence.
4) Added manual modes for uni-direction and bi-direction alignments
3) Improves overall operation when using SpectroProofer.
2) Correction for possible paper handling issue on two specific media types:
Enhanced Adhesive Synthetic Paper
Enhanced Synthetic Paper
1) Added support for the use of 150ml UltraChrome HDR ink cartridges