Sheet transport device and non-transitory computer readable medium

1. A sheet transport device comprising a processor configured to change lifting control for lifting sheets on a tray, which are to be floated up and handed over, from normal state control to small-quantity state control in a case where it is detected that a remaining number of sheets on the tray is small, wherein

the processor lifts the sheets by a small-quantity state lifting amount, which is larger than a lifting amount during the normal state control, in a case where it is detected that the remaining number of sheets has decreased by a predetermined number during the small-quantity state control, and

the processor executes a lifting amount adjusting processing in a case where the tray is at a position higher by a predetermined amount than a reference height for detecting that the number of sheets is small before start of transport of the sheets from the tray,

during the lifting amount adjusting processing, the processor lifts the sheets by adjusting a lifting amount by which the tray is lifted based on a relative difference value of a current height of the tray with respect to the reference height, wherein the processor subtracts the reference height from the current height of the tray to obtain an excess amount and subtracts the excess amount from the small-quantity state lifting amount to obtain a subtracted amount, and the processor set the subtracted amount as the lifting amount by which the tray is lifted.

2. The sheet transport device according to claim 1 , wherein

the processor detects that the remaining number of sheets is small and that the remaining number of sheets has decreased by the predetermined number by different methods.

3. The sheet transport device according to claim 2 , wherein

the processor detects that the remaining number of sheets has decreased by the predetermined number on a basis of the number of sheets transported from the tray after the change to the small-quantity state control.

4. The sheet transport device according to claim 3 , wherein

the number of sheets used for the detection is larger in a case where a thickness of the sheets is small than in a case where the thickness of the sheets is large.

5. The sheet transport device according to claim 4 , wherein

during the small-quantity state control, the processor lifts the sheets by controlling an air blow amount for floating up the sheets.

6. The sheet transport device according to claim 3 , wherein

during the small-quantity state control, the processor lifts the sheets by controlling an air blow amount for floating up the sheets.

7. The sheet transport device according to claim 2 , wherein

during the small-quantity state control, the processor detects that the remaining number of sheets has decreased by the predetermined number on a basis of a lifting amount by which the tray is lifted in accordance with a height of the sheets on the tray.

8. The sheet transport device according to claim 7 , wherein

during the small-quantity state control, the processor lifts the sheets by controlling an air blow amount for floating up the sheets.

9. The sheet transport device according to claim 2 , wherein

during the small-quantity state control, the processor lifts the sheets by controlling an air blow amount for floating up the sheets.

10. The sheet transport device according to claim 1 , wherein

during the small-quantity state control, the processor lifts the sheets by controlling an air blow amount for floating up the sheets.

11. The sheet transport device according to claim 1 , wherein

during the small-quantity state control, the processor makes the lifting amount by which the tray is lifted larger in a case where a thickness of the sheets is large than in a case where the thickness of the sheets is small.

12. The sheet transport device according to claim 1 , wherein

during the small-quantity state control, the processor makes the lifting amount by which the tray is lifted larger in a case where a width dimension of the sheets is large than in a case where the width dimension of the sheets is small.

13. The sheet transport device according to claim 1 , wherein

during the small-quantity state control, the processor makes the lifting amount by which the tray is lifted larger in a case where a length dimension of the sheets is large than in a case where the length dimension of the sheets is small.

14. A non-transitory computer readable medium storing a program causing a computer to execute a process comprising:

changing lifting control for lifting sheets on a tray, which are to be floated up and handed over, from normal state control to small-quantity state control in a case where it is detected that a remaining number of sheets on the tray is small, wherein

the sheets are lifted by a small-quantity state lifting amount, which is larger than a lifting amount during the normal state control, in a case where it is detected that the remaining number of sheets has decreased by a predetermined number during the small-quantity state control, and

a lifting amount adjusting processing is executed in a case where the tray is at a position higher by a predetermined amount than a reference height for detecting that the number of sheets is small before start of transport of the sheets from the tray,

during the lifting amount adjusting processing, the sheets are lifted by adjusting a lifting amount by which the tray is lifted based on a relative difference value of a current height of the tray with respect to the reference height, wherein the reference height is subtracted from the current height of the tray to obtain an excess amount and subtracts the excess amount from the small-quantity state lifting amount to obtain a subtracted amount, and the subtracted amount is set as the lifting amount by which the tray is lifted.