Sheet folder, image forming apparatus incorporating the sheet folder, and image forming system incorporating the sheet folder

A sheet folder comprising:

• a conveyor to convey a sheet along a main conveyance path in a conveyance direction;
• a pair of a first folding roller and a second folding roller downstream from the conveyor in the conveyance direction, the first folding roller and the second folding roller contactable with each other to form a first nip in the main conveyance path;
• a third folding roller:
• between the conveyor and the first nip in the conveyance direction;
• away from the main conveyance path;
• and
• contactable with the second folding roller to form a second nip in a branch conveyance path branched from the main conveyance path, the second nip between the conveyor and the first nip in the conveyance direction;
• a first guide between the conveyor and the first nip in the conveyance direction, the first guide movable between:
• a first guide posture to guide the sheet to the first nip;
• and
• a first retracted posture to guide the sheet to the second nip;
• a second guide between the conveyor and the first nip in the conveyance direction and facing the first guide, the second guide being farther from the third folding roller than the first guide, the second guide movable between:
• a second guide posture to guide the sheet to the second nip;
• and
• a second retracted posture to guide the sheet to the first nip;
• and
• a motor to:
• rotate the second folding roller in a forward direction to convey the sheet toward the first nip;
• rotate the second folding roller in a reverse direction to convey the sheet toward the second nip;
• move the first guide to arrange the first guide in one of the first guide posture and the first retracted posture;
• and
• move the second guide to arrange the second guide in one of the second guide posture and the second retracted posture,
• the sheet folder further comprising a driving-force transmission to transmit a rotational driving force of the motor to the first guide and the second guide,
• wherein the driving-force transmission:
• rotates the first guide from the first retracted posture to the first guide posture and rotates the second guide from the second guide posture to the second retracted posture, in conjunction with rotation of the second folding roller in the forward direction, and
• rotates the first guide from the first guide posture to the first retracted posture and rotates the second guide from the second retracted posture to the second guide posture, in conjunction with rotation of the second folding roller in the reverse direction,
• wherein the sheet folder further comprises circuitry configured to:
• control the conveyor to convey the sheet toward the first nip in the conveyance direction;
• control the first folding roller, the second folding roller, and the third folding roller to rotate in the reverse direction;
• control the first guide to be arranged in the first retracted posture;
• and
• control the second guide to be arranged in the second guide posture,
• to convey the sheet to the second nip to form a first fold portion in the sheet;
• and
• control the first folding roller, the second folding roller, and the third folding roller to rotate in the forward direction;
• control the first guide to be arranged in the first guide posture;
• and
• control the second guide to be arranged in the second retracted posture,
• to convey a portion of the sheet different from the first fold portion to the first nip to form a second fold portion in the sheet.

A sheet folder, comprising:

• a conveyor to convey a sheet along a main conveyance path in a conveyance direction;
• a pair of a first folding roller and a second folding roller downstream from the conveyor in the conveyance direction, the first folding roller and the second folding roller contactable with each other to form a first nip in the main conveyance path;
• a third folding roller:
• between the conveyor and the first nip in the conveyance direction:
• away from the main conveyance path;
• and
• contactable with the second folding roller to form a second nip in a branch conveyance path branched from the main conveyance path, the second nip between the conveyor and the first nip in the conveyance direction:
• a first guide between the conveyor and the first nip in the conveyance direction, the first guide movable between:
• a first guide posture to guide the sheet to the first nip;
• and
• a first retracted posture to guide the sheet to the second nip:
• a second guide between the conveyor and the first nip in the conveyance direction and facing the first guide, the second guide being farther from the third folding roller than the first guide, the second guide movable between:
• a second guide posture to guide the sheet to the second nip;
• and
• a second retracted posture to guide the sheet to the first nip;
• and
• a motor to:
• rotate the second folding roller in a forward direction to convey the sheet toward the first nip;
• rotate the second folding roller in a reverse direction to convey the sheet toward the second nip;
• move the first guide to arrange the first guide in one of the first guide posture and the first retracted posture;
• and
• move the second guide to arrange the second guide in one of the second guide posture and the second retracted posture,
• the sheet folder further comprising a driving-force transmission to transmit a rotational driving force of the motor to the first guide and the second guide,
• wherein the driving-force transmission:
• rotates the first guide from the first retracted posture to the first guide posture and rotates the second guide from the second guide posture to the second retracted posture, in conjunction with rotation of the second folding roller in the forward direction, and
• rotates the first guide from the first guide posture to the first retracted posture and rotates the second guide from the second retracted posture to the second guide posture, in conjunction with rotation of the second folding roller in the reverse direction,
• wherein the sheet folder further comprises circuitry configured to:
• control the conveyor to convey the sheet toward the first nip in the conveyance direction;
• control the first folding roller, the second folding roller, and the third folding roller to rotate in the reverse direction;
• control the first guide to be arranged in the first retracted posture;
• and
• control the second guide to be arranged in the second guide posture,
• to convey a leading edge of the sheet to the second nip;
• and
• control the first folding roller, the second folding roller, and the third folding roller to rotate in the forward direction;
• control the first guide to be arranged in the first guide posture;
• and
• control the second guide to be arranged in the second retracted posture,
• to convey a portion of the sheet different from the leading edge of the sheet to the first nip to form a fold portion in the sheet.