Abstract: Provided is a piezoelectric actuator that can reduce a risk of air leakage due to weakening of pressing force of a valve element against a valve seat surface and airtightness. The piezoelectric actuator is used for a piezoelectric valve that opens and closes a valve utilizing displacement of a laminated piezoelectric element. The piezoelectric actuator includes: a valve element; a laminated piezoelectric element that generates a driving force, required for operation of the valve element, as a displacement; and a displacement enlargement mechanism that enlarges a displacement of a laminated piezoelectric element and causes the enlarged displacement to act on the valve element. In the piezoelectric actuator, a surface of the valve element to be in contact with a valve seat of the piezoelectric valve is made flat and smooth in a state in which a tensile load is applied to the laminated piezoelectric element.

Abstract: An imaging unit including a line sensor reads a film image to produce color decomposition data by scanning a plurality of lines on the film image in a stepped prescanning operation. During the prescanning operation, the color decomposition data of a plurality of pixels at each of a plurality of sampling points are sampled and added up on a line-by-line basis, and the added color decomposition data are averaged, where corrections including a shading correction are performed concurrently with the adding and averaging operations. During a period of from the end of the prescanning operation to the start of a main scanning operation, on the basis of the averaged color decomposition data, a density correction amount is determined and parameters to be used for correcting the film image in a succeeding actual image processing operation are calculated. The calculated parameters are set in a line memory.