Missing Nozzle Diagnosis; Definitions - Epson Stylus pro 7900 Repair Manual

Pro 7900 and 9900 Field Repair Guide
Note: It is important to completely clean the Printer before following the troubleshooting advice in this
chapter. This is because a dirty printer will cause any of the symptoms listed. Follow the cleaning
advice in the Service Procedure chapter in the reference section.

Definitions

Channel: a column of 360 nozzles.
Color Pair: 2 channels that share a Cap on the Cleaning Station.
Reverse Flow: a term describing a condition that exists after a strong cleaning cycle. The Ink System pulls back-
wards drawing air into the Print Head's Nozzle Plate. The air in the Nozzle Plate causes missing
nozzles until the air is expelled.
Overview
There are 5 categories of Missing Nozzles. Read them all, and decide which scenario fits the issue.
1 Channel Missing (completely, or almost completely).
The most likely cause is an Ink supply issue. The ink is not reaching the Print Head effectively.
1. Test the Ink Cartridge.
1.1 To test the Ink Cartridge, manually pressurize the Cartridge, and manually open the Valve to verify that
ink will flow. See the INK CARTRIDGE ERROR: REPLACE INK CARTRIDGE chapter in the
Troubleshooting section.
2. Replace the related Damper. It is recommended that you replace all 5 Dampers.
3. Replace the Print Head.
Note: If this symptom is caused by the Print Head, then the ink inlet for the missing channel is clogged.

Missing Nozzle Diagnosis

Missing Nozzle Diagnosis
Printer Component, Software Item, LCD Display, Printer Button
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