Patent ID: 6945721
Filing Date: 2005-09-20
Classification: B41J

Abstract:
1. An edge-detecting device for detecting an edge of a medium, the device comprising: a detecting unit that defines a target detection area, and that detects medium detection data at the target detection area, the medium detection data having a different value depending on whether or not a medium is present in the target detection area; an adjusting unit that performs an adjusting operation by controlling the detecting unit to detect values of the medium detection data at a plurality of locations on the medium, thereby adjusting a determining condition based on the plurality of detected values; and an edge detecting unit that performs an edge detecting operation by controlling the detecting unit to detect a value of the medium detection data while moving the position of the target detection area in relation to the medium and by determining whether or not the medium is present in the target detection area based on the value detected by the detecting unit and by using the adjusted determining condition, thereby detecting an edge position of the medium; wherein the detecting unit includes a reflection-type sensor having a light-emitting element and a light-receiving element, the light-receiving element receiving light reflected from the target detection area when the light-emitting element emits light, the light-receiving element outputting data indicative of an amount of light received by the light-receiving element as the medium detection data; wherein the edge detecting unit determines whether the medium is present in the target detection area based on whether the amount of light received by the light-receiving element exceeds a threshold value; and wherein the adjusting unit includes a light-emitting adjusting unit that adjusts the amount of light emitted by the light-emitting element at the plurality of locations to such a value that causes the light-receiving element to receive light with an amount of a predetermined value.