Sheet inverting unit and an imaging forming apparatus employing the same

A double-side image forming apparatus, for forming images on both sides of a sheet, comprising:

• an image forming device for forming an image on one surface of a sheet, the image forming device having
• a sheet cassette for retaining sheets,
• an image forming mechanism provided above the sheet cassette for forming an image on one side of a sheet supplied from the sheet cassette;
• a stacker provided above the image forming mechanism for holding an image bearing sheet,
• a feeding path along which the sheet supplied from the sheet cassette is conveyed first to the image forming mechanism and then to the stacker,
• a manual inserting port for manual sheet insertion, and
• a manual inserting path along which a manually inserted sheet is conveyed from the manual inserting port to the upstream origin of the feeding path for the image forming mechanism;
• and
• a sheet inverting unit for inverting and feeding a sheet bearing an image on one side to the image forming device, the sheet inverting unit having
• a switching lever provided downstream along the feeding path of the image forming mechanism for selectively guiding the image bearing sheet either toward the stacker or upward of the image forming device,
• switchback rollers for feeding, upward of the stacker, the image bearing sheet that is guided upward by said switching lever and then inversely feeding the image bearing sheet,
• a guide path that extends from the switchback rollers to a terminus in the vicinity of the manual inserting port of the image forming device, and
• feeding rollers provided along the guide path for feeding the image bearing sheet to the image forming device.

A double-side image forming apparatus, for forming images on both sides of a sheet, comprising:

• an image forming device for forming an image on one surface of a sheet, the image forming device having
• a sheet cassette for retaining sheets,
• an image forming mechanism provided above the sheet cassette for forming an image on one side of a sheet supplied from the sheet cassette,
• a stacker provided above the image forming mechanism for holding an image bearing sheet,
• a feeding path along which the sheet supplied from the sheet cassette is conveyed first to the image forming mechanism and then to the stacker,
• an insertion port for sheet insertion, and
• an insertion path along which an inserted sheet is conveyed from the insertion port to the upstream origin of the feeding path for the image forming mechanism;
• and
• a sheet inverting unit for inverting and feeding a sheet bearing an image on one side to the image forming device, the sheet inverting unit having
• a switching lever provided downstream along the feeding path of the image forming mechanism for selectively guiding the image bearing sheet either toward the stacker or upward of the image forming device,
• switchback rollers for feeding, upward of the stacker, the image bearing sheet that is guided upward by the switching lever and then inversely feeding the image bearing sheet,
• a guide path that extends from the switchback rollers to a terminus in the vicinity of the insertion port of the image forming device, and
• feeding rollers provided along the guide path for feeding the imager bearing sheet to the image forming device.

A double-side image forming apparatus, for forming images on both sides of a sheet, comprising:

• a sheet cassette for retaining sheets;
• an image forming mechanism, provided above the sheet cassette, for forming an image on one side of a sheet supplied from the sheet cassette;
• a stacker, provided above the image forming mechanism, for holding an image bearing sheet;
• a feeding path, along which the sheet supplied from the sheet cassette is conveyed first to the image forming mechanism and then to the stacker;
• an insertion port for sheet insertion;
• an insertion path, along which an inserted sheet is conveyed from the insertion port to the upstream origin of the feeding path for the image forming mechanism;
• a sheet exit port provided downstream along the feeding path of the image forming mechanism;
• a switching lever, provided downstream along the feeding path of the image forming mechanism, for selectively guiding the image bearing sheet either toward the stacker or toward the sheet exit port;
• switchback rollers for feeding, upward of the stacker, the image bearing sheet guided toward the sheet exit port by the switching lever and then inversely feeding the image bearing sheet;
• a guide path that extends from the switchback rollers to a terminus in the vicinity of the insertion port;
• and
• feeding rollers, provided along the guide path, for feeding the image bearing sheet to the insertion port.