Medium processing device

1. A medium processing device, comprising:

a conveyance guide that forms a conveyance path through which a medium is conveyable, and that guides the medium along the conveyance path in a conveyance direction;

a reference surface guide that is provided at one side of the conveyance path, and that limits a conveyance range of the conveyance path in a width direction which is orthogonal to the conveyance direction of the medium;

a trigger sensor that detects a rear end of the medium in the conveyance direction; and

a first alignment roller and a second alignment roller for aligning the medium with the reference surface guide, each of the first and second alignment rollers being so disposed that an axis direction that extends along a rotation axis thereof is inclined with respect to the conveyance direction, wherein

the first alignment roller is provided at the middle, in a width of the conveyance path, and the second alignment roller is provided between the reference surface guide and the first alignment roller in the width direction,

the second alignment roller is provided at a downstream side of the first alignment roller in the conveyance direction,

a space from the first alignment roller to the second alignment roller in the conveyance direction is longer than a space from the trigger sensor to the first alignment roller in the conveyance direction,

a width of the conveyance path in the width direction is not more than twice of a width of a minimum sized medium in the width direction, the width of the minimum sized medium being a shortest width in the width direction of all media to be handled in the medium processing device,

the minimum sized medium is of a rectangular shape, and has a first side and a second side that are parallel to each other and that are along the conveyance direction when the minimum sized medium is aligned with the reference surface guide, the first side being closer to the reference surface guide than the second side,

when the minimum sized medium is not aligned with the reference surface guide and an upstream end of the first side is closer to the reference surface guide than a downstream end of the first side, the first side abuts on the reference surface guide at an upstream contact point,

the first alignment roller is disposed at the downstream side in the conveyance direction with respect to the upstream contact point, such that the minimum sized medium comes into contact with the reference surface guide when the trigger sensor has detected the rear end of the minimum sized medium, and

the first alignment roller is disposed such that an intersection point of an extension line that extends along the rotation axis of the first alignment roller and the reference surface guide is positioned at the downstream side in the conveyance direction with respect to the upstream contact point.

2. The medium processing device of claim 1 , wherein the second alignment roller is disposed at approximately a center between the reference surface guide and the first alignment roller in the width direction.

3. The medium processing device of claim 2 , wherein

when the minimum sized medium is not aligned with the reference surface guide and the downstream end of the first side is closer to the reference surface guide than the upstream end of the first side, the first side abuts on the reference surface guide at an downstream contact point,

the second alignment roller is disposed at an upstream side in the conveyance direction with respect to the downstream contact point, such that the minimum sized medium comes into contact with the reference surface guide when the rear end of the minimum sized medium passes through the first alignment roller.

4. The medium processing device of claim 1 , further comprising a conveyance roller conveying the medium in the conveyance direction, wherein

a feeding speed of each of the first and second alignment rollers is faster than a feeding speed of the conveyance roller.

5. The medium processing device of claim 4 , wherein, if the feeding speed of each of the first and second alignment rollers is divided into a feeding speed component in the conveyance direction and a feeding speed component in the width direction, the feeding speed in the conveyance direction of each of the first and second alignment roller is approximately equal to the feeding speed of the conveyance roller.

6. The medium processing device of claim 1 , further comprising a detection sensor that is disposed in a vicinity of the reference surface guide, and that detects whether the medium has abutted on the reference surface guide.

7. The medium processing device of claim 6 , wherein

the detection sensor includes two or more detection sensors, and

the two or more detection sensors are disposed so as to detect whether the minimum sized medium has aligned along the reference surface guide, the minimum sized medium having a shortest length in the conveyance direction of all media to be handled in the medium processing device.

8. The medium processing device of claim 7 , wherein

the two or more detection sensors include a first detection sensor and a second detection sensor, and

a space between the first detection sensor and the second detection sensor is shorter than the length of the minimum sized medium in the conveyance direction.

9. The medium processing device of claim 6 , wherein

the detection sensor includes at least two detection sensors, and

the at least two detection sensors are disposed so as to detect whether the minimum sized medium, which is conveyed from a position in the width direction farthest from the reference surface guide by the first and second alignment rollers when the minimum sized medium passes through the trigger sensor, has abutted on the reference surface guide.

10. The medium processing device of claim 1 , wherein a first angle between a first alignment conveyance direction that is orthogonal to the axis direction that extends along the rotation axis of the first alignment roller and the conveyance direction is smaller than a second angle between a second alignment conveyance direction that is orthogonal to the axis direction that extends along the rotation axis of the second alignment roller and the conveyance direction.

11. The medium processing device of claim 1 , wherein the first alignment roller and the second alignment roller are configured to sandwich the medium.

12. The medium processing device of claim 1 , wherein a conveyance roller that conveys the medium in the conveyance direction is disposed outside a portion of the conveyance path that is between the first alignment roller and the trigger sensor.