IMAGE READING APPARATUS HAVING FIRST MOTOR FOR ROTATING FEED ROLLER, AND SECOND MOTOR FOR ROTATING CONVEYANCE ROLLER AND REVERSE ROLLER

摘要

In an image reading apparatus, in a first process, first and second motor rotate feed and conveyance rollers with circumferential speeds of first and second speeds, respectively. In the first process, the reverse roller has a first separation performance for separating a sheet from another sheet. In a second process, after a detector detects a leading edge of the sheet, the controller stops the first motor, and decelerates the second motor, and the reverse roller has a second separation performance lower than the first separation performance. In a third process, after a trailing edge of the sheet reaches a specific position, the first motor starts rotating the feed roller with the circumferential speed of the first speed. In a fourth process, after the trailing edge of the sheet passes through a reading end position, the controller accelerates the second motor.

主权项

1. An image reading apparatus comprising:
a first motor; a second motor; a feed roller configured to rotate in a rotational direction by torque generated by the first motor so as to convey a sheet to in a conveyance direction; a reverse roller configured to be in peripheral contact with the feed roller, and configured to rotate in the rotational direction by torque received from the second motor via a torque limiter; a conveyance roller disposed downstream of the feed roller in the conveyance direction, and configured to rotate in the rotational direction by torque from the second motor so as to convey the sheet from the feed roller in the conveyance direction, a circumferential speed of the conveyance roller varying depending on a circumferential speed of the reverse roller; a reader disposed downstream of the conveyance roller in the conveyance direction and configured to read an image on the sheet at a reading position; a detector disposed between the conveyance roller and the reading position in the conveyance direction and configured to detect the sheet; and a controller comprising hardware configured to perform processes comprising: a first drive process in which the controller is configured to control the first motor and the second motor to rotate the feed roller with the circumferential speed of a first speed and the conveyance roller with the circumferential speed of a second speed, wherein the reverse roller is configured to be rotated with the circumferential speed of a third speed in the first drive process so that the reverse roller has a first separation performance for separating a sheet from other sheets, which are in an overlapped state, together with the feed roller with the circumferential speed of the first speed, wherein the feed roller conveys a specific sheet in the conveyance direction through the first drive process; a second drive process in which, in response to detection of a leading edge of the specific sheet by the detector after performing the first drive process, the controller is configured to stop the first motor, and to decelerate the second motor to rotate the conveyance roller with the circumferential speed of a fourth speed slower than both the first speed and the second speed, wherein when the circumferential speed of the conveyance roller is the fourth speed in the second drive process, the reverse roller is configured to be rotated with the circumferential speed of a fifth speed so that the reverse roller has a second separation performance for separating a sheet from other sheets which are in an overlapped state, wherein the fifth speed is slower than the third speed and the second separation performance is lower than the first separation performance, wherein the conveyance roller conveys the specific sheet through the second drive process; a third drive process in which, in response to conveying the specific sheet through the second drive process so that a trailing edge of the specific sheet reaches a first position after the detector detects the trailing edge of the specific sheet, the controller is configured to control the first motor to start rotating the feed roller with the circumferential speed of the first speed, wherein the first position is located between the detector and the reading position, and the first position is separated from the detector by a prescribed distance; and a fourth process in which, in response to passage of the trailing edge of the specific sheet through a reading end position after performing the third drive process, the controller is configured to accelerate the second motor to rotate the conveyance roller with the circumferential speed of the second speed while the circumferential speed of the feed roller is maintained to the first speed, the reading end position being downstream of the first position in the conveyance direction.