Image forming apparatus and image erasing apparatus

An image forming apparatus comprising:

• a tray in which sheets are stacked;
• a detecting sensor which detects whether a mark indicating a reusable sheet is assigned to the sheets in the tray;
• a cumulative unit which cumulates the sheets of which the mark is not detected by the detecting sensor;
• a sheet cassette which receives the sheets of which the mark is detected by the detecting sensor;
• a color erasing unit which erases a color of an erasable image forming material attached onto the sheets taken out from the sheet cassette;
• and
• an image forming unit which forms an image by attaching the image forming material onto the sheets of which the image forming material is erased by the color erasing unit.

An image erasing apparatus comprising:

• a heat source which heats a sheet on which an image is formed with an image forming material erasable by heating;
• a belt which applies heat supplied from the heat source to the sheet being brought into contact with the belt while being transported;
• and
• a sheet cassette which receives the sheet to which the heat supplied from the heat source is applied through the belt.

A sheet processing method used in an image forming apparatus, comprising:

• detecting whether a mark indicating a reusable sheet is assigned to a sheet;
• cumulating the sheet of which the mark is not detected in a cumulative unit;
• erasing an image forming material attached to the sheet of which the mark is detected;
• receiving the sheet of which the image forming material is erased in a sheet cassette;
• and
• forming an image by attaching the image forming material to the sheet received in the sheet cassette.

An image forming apparatus comprising:

• a first sheet holding section holding a sheet;
• a first sheet transporting section which transports the sheet held by the first sheet holding section;
• a detecting sensor which detects whether the sheet transported by the first sheet transporting section has a mark indicating a reusable sheet;
• a second sheet transporting section which transports the sheet detected as the reusable sheet by the detecting sensor;
• a image erasing unit which erases an image on the sheet transported by the second sheet transporting section;
• and
• a second sheet holding section which holds the sheet which the image is erased by the image erasing unit.

An image forming method comprising:

• transporting a sheet held by a first sheet holding section;
• detecting whether the sheet has a mark indicating a reusable sheet while transported;
• erasing an image on the sheet detected as a reusable sheet;
• and
• holding the sheet which the image is erased.