Sheet feeder and image forming system

An image forming system, comprising:

• a sheet feeder, the sheet feeder comprising:
• a tray;
• a feeder roller configured to contact an object sheet being a topmost one of the plurality of sheets in the stack in the tray to feed the object sheet in a feeding direction by rotating;
• a guide disposed downstream of the feeder roller in the feeding direction to adjoin the tray, the guide comprising a guiding surface extending from a bottom of the tray in a predetermined direction, the predetermined direction containing a direction of the sheets to be stacked in the tray and the feeding direction, and the guiding surface being arranged to incline at an obtuse angle with respect to the object sheet fed to contact the guiding surface by the feeder roller;
• a separator arranged on the guide to protrude from the guiding surface toward a space in the tray to accommodate the plurality of sheets to align with the predetermined direction, the separator being configured to separate the object sheet fed by the rotation of the feeder roller from the other of the plurality of sheets;
• a motor configured to drive the feeder roller to rotate;
• a controller configured to control the motor;
• and
• a sensor configured to input a signal corresponding to a remaining volume of the plurality of sheets in the tray to the controller, and
• an image forming apparatus configured to form an image on the object sheet fed by the sheet feeder,
• wherein the controller of the sheet feeder is configured to:
• based on the signal input by the sensor, determine the remaining volume of the plurality of sheets in the tray;
• generate a velocity profile defining a target velocity to feed the object sheet from a start to an end of a sheet-feeding operation, so that the object sheet is fed at a lower velocity in a first period than a velocity in a second period, the second period being later than the first period, in the sheet-feeding operation;
• based on the determined remaining volume of the plurality of sheets, modify at least one of a length of the first period and the target velocity in the first period of the velocity profile;
• and
• after a modification of the velocity profile, control the motor in compliance with the modified velocity profile.

A method adapted to be implemented on a controller coupled with a sheet feeder, the method comprising:

• based on a signal input to the controller by a sensor of the sheet feeder, determining a remaining volume of a plurality of sheets stacked in a tray of the sheet feeder;
• generating a velocity profile defining a target velocity to feed a topmost sheet which is one of the plurality of sheets stacked in the tray from a start to an end of a sheet-feeding operation, so that the topmost sheet is fed at a lower velocity in a first period than a velocity in a second period, the second period being later than the first period, in the sheet-feeding operation;
• based on the determined remaining volume, modifying at least one of a length of the first period and the target velocity in the first period of the velocity profile;
• and
• after a modification of the velocity profile, controlling a motor in the sheet feeder in compliance with the modified velocity profile.