Doctor Blade Tone Variation.

The conclusions reached were: (1) At least half of the so-called doctor blade tone variation is not caused primarily by the doctor blade or its mechanism. These variations can be cured by using better fitting sleeves and bearings. (2) Local wear of the doctor blade in image areas, variable speed of blades, and small angle of bridge to cylinder are not major causes of cyclic variations. (3) The purely cyclical variation found in the study could only be attributed to cylinders having a high end, traceable to electroplating conditions. (4) No other causes of cyclic tone variation have as yet been definitely identified from these measurements.