US 5,331,680 AGranted

Position detecting apparatus

AssigneeTokyo Electric Co., Ltd.

InventorShigenori Ueno

Life of this patent

Estimating the term…

Loading patent…

Abstract

A position detecting apparatus comprises a motion detecting section for generating a pulse when a carriage passes each of coordinate points set in a reciprocal movement span thereof at a predetermined pitch, and a counting section for storing position data representing an initial position of the carriage in advance, incrementing the position data in response to a pulse which is generated by the motion detecting section when the carriage is moved in the forward direction, and decrementing the position data in response to a pulse which is generated by the motion detecting section when the carriage is moved in the backward direction. Particularly, the position detecting apparatus further comprises a position data correcting section for controlling the counting section to correct the position data when the carriage is moved in the backward direction so that the position data represents a position shifted in the forward direction by a predetermined amount and to cancel the correction when the carriage is moved in the forward direction.

Claims7

Dependent claims

A position detecting apparatus for use in a bidirectional printer having a carriage and a print head mounted on the carriage, the print head driven to produce printing while the carriage is moving in forward and backward directions along an axis on which coordinate points are set at a predetermined pitch, comprising:

motion detecting means for detecting a first motion of said carriage passing one of the coordinate points during one of forward and backward movements thereof, and for detecting a second motion of said carriage passing one of the coordinate points during the other one of the forward and backward movements thereof;
counting means for storing position data representing a current position of said carriage, for updating the position data by incrementing the position data upon detection of the first motion and by decrementing the position data upon detection of the second motion, thereby causing the print head to be driven each time the position data is updated;
and
correcting means for correcting the position data in said counting means when the moving direction of said carriage is reversed from one of the forward and backward directions to the other of the forward and backward directions, the amount of correction being determined to reduce a difference between printing positions set during said forward and backward movements for the same position data.

1 more element

Dependencies are inferred from the claim text.