Image reader, and method and computer-readable medium for the same

摘要

An image reader including a document table having a reference point, a first region of a sheet having a predetermined size when a vertex of the sheet is positioned on the reference point, and a second region, a changing mechanism changing a reading position in a sub scanning direction, and a controller configured to control the changing mechanism to change the reading position to a first position such that a distance in the sub scanning direction between the reference point and the first position corresponds to a length of the predetermined sheet size in the sub scanning direction, acquire specific digital data of the second region through image reading in the first position with a light source turned off, compare a particular value of the specific digital data with a criterion value within the second region, and determine a state of a document cover based on the comparison.

主权项

1. An image reader comprising:
a document table configured to support a document placed thereon, the document table having:
a reference point on which a vertex of the document is positioned;a first region defining an area of a predetermined sheet size with respect to the reference point; anda second region different from the first region; a document cover movable between an open state and a closed state, the document cover being configured to cover an upper surface of the document table when the document cover is in the closed state; a reading unit comprising a light source configured to emit light toward the document placed on the document table, the reading unit being configured to perform image reading on a line-by-line basis along a main scanning direction, and output analog data as read data; a converter configured to convert the analog data output from the reading unit into digital data; a changing mechanism configured to change a reading position where image reading is performed, in a sub scanning direction perpendicular to the main scanning direction; a reference member attached to the document table; and a controller configured to:
control the changing mechanism to change the reading position to a first position, the first position being such a position that a distance in the sub scanning direction between the reference point and the first position corresponds to a length of the predetermined sheet size in the sub scanning direction;acquire specific digital data of the second region through image reading in the first position with the light source turned off, including acquiring black data by controlling the reading unit to perform image reading of the reference member;compare a particular value of the specific digital data with a predetermined criterion value within the second region to determine a maximum value of the black data within the second region in the main scanning direction and determine the predetermined criterion value based on the determined maximum value;determine an open/closed state of the document cover, based on the comparison of the particular value of the specific digital data with the predetermined criterion value within the second region, including when determining that the particular value of the specific digital data is higher than the predetermined criterion value within the second region in the main scanning direction, determine that the document cover is in the open state; andafter determining that the document cover is in the open state, when determining that the particular value of the specific digital data becomes equal to or lower than the predetermined criterion value within the second region, determine that the document cover is in a state immediately before brought into the closed state.