In an automatic feeder and an image acquiring apparatus, a cover is rotatably connected to a body through a first pin and openable and closable with respect to the body. The invention also relates to a process for the preparation of alkylene oxide using such catalyst. The inner housing is rotatably mounted inside the outer housing to permit rotation of the inner housing along with the axle within the outer housing. Each linear graduation mark, when aligned with a proximal end of the measurement tube, provides a linear measure of the distance between a distal end of the measurement tube and a cutting member of the retrograde reamer positioned so that its central axis is disposed at a non-zero angle relative to a longitudinal axis of the tubular shaft. The inner ring of the bearing portion is fixed to the cylindrical portion of the hub shaft. Efficient distribution of workload may improve the performance of the image processing system.