Image Forming Apparatus and Image Forming Method

An image forming apparatus comprising:

• a latent image holder that holds an electrostatic latent image in which an image portion to which toner is to be adhered and a non-image portion to which toner is not to be adhered have different potentials;
• a toner carrying roller that has a roller shape to be opposed to the latent image holder with a predetermined gap therebetween, and carries a toner layer including both the contact toner which directly contacts a surface of the roller and non-contact toner which contacts the contact toner but does not contact the surface of the roller;
• and
• an electric field forming unit that forms an alternating electric field to cause the toner on a surface of the toner carrying roller to fly between the latent image holder and the toner carrying roller, as a toner fly electric field,
• wherein the non-contact toner is caused to fly, but the contact toner is not caused to fly, between the non-image portion on the surface of the latent image holder and the surface of the toner carrying roller, at a position where the latent image holder and the toner carrying roller are opposed to each other.

An image forming method comprising:

• disposing a latent image holder that holds an electrostatic latent image and a toner carrying roller having a roller shape to be opposed to each other with a predetermined gap therebetween;
• forming an electrostatic latent image in which an image portion to which toner is to be adhered and a non-image portion to which toner is not to be adhered have different potentials, on a surface of the latent image holder;
• forming a toner layer including both contact toner which directly contacts a surface of the roller and non-contact toner which contacts the contact toner but does not contact the surface of the roller on a surface of the toner carrying roller to be transported to a position opposed to the latent image holder;
• forming an alternating electric field to cause toner on the surface of the toner carrying roller to fly between the latent image holder and the toner carrying roller, as a toner fly electric field, thereby developing the electrostatic latent image with the toner;
• and
• causing the non-contact toner to fly and the contact toner not to fly between the non-image portion on the surface of the latent image holder and the surface of the toner carrying roller, at a position where the latent image holder and the toner carrying roller are opposed to each other.