Image forming method and apparatus using charged particles

An image forming apparatus for developing an electrostatic latent image on an electrostatic latent image support by use of mist-like charged particles and thereby making visible the electrostatic latent image, the apparatus comprising a developing electrode provided at a space from the electrostatic latent image support to extend substantially in parallel to the surface of the electrostatic latent image support on which the electrostatic latent image is formed,

• a gap control member provided on at least a part of the perimeter of the developing electrode to extend toward the surface of the electrostatic latent image support from the periphery of the developing electrode so that the space between the gap control member and the surface of the electrostatic latent image support is smaller than the space between the developing electrode and the surface of the electrostatic latent image support, thereby forming a developing space defined by the electrostatic latent image support, the developing electrode and the gap control member,
• a mist supply means for introducing mist-like charged particles into the developing space,
• an electric voltage application means which applies an electric voltage to the developing electrode to form an electric field between the electrostatic latent image support and the developing electrode, and
• a drive means for moving the electrostatic latent image support and the developing space relative to each other.

An image forming method of developing an electrostatic latent image on an electrostatic latent image support by use of mist-like charged particles and thereby making visible the electrostatic latent image, the method comprising the steps of

• providing a mist supply passage which has an opening in a position opposed to the electrostatic latent image support,
• forming a laminar flow of mist-like charged particles in the mist supply passage,
• forming a laminar flow of gas such as air free from the mist-like charged particles between the laminar flow of the mist-like charged particles and the inner surface of the mist supply passage at least on the side nearer to the electrostatic latent image support at least at a part of the mist supply passage near the opening,
• providing a first bias electrode near the opening of the mist supply passage,
• providing a second bias electrode on the inner surface of the mist supply passage opposite to the opening, and
• applying electric potentials to the first and second bias electrodes so that an electric field is formed in a direction perpendicular to the laminar flow of the mist-like charged particles and the mist-like charged particles are moved by the electric field toward the electrostatic latent image support passing through the laminar flow of the gas and the opening of the mist supply passage to adhere to the electrostatic latent image support and develop the electrostatic latent image.

An image forming apparatus for developing an electrostatic latent image on an electrostatic latent image support by use of mist-like charged particles and thereby making visible the electrostatic latent image, the apparatus comprising

• a mist supply passage which has an opening in a position opposed to the electrostatic latent image support,
• a means for forming a laminar flow of mist-like charged particles in the mist supply passage, and
• a means for forming a laminar flow of gas such as air free from the mist-like charged particles between the laminar flow of the mist-like charged particles and the inner surface of the mist supply passage at least on the side nearer to the electrostatic latent image support along at least a part of the mist supply passage near the opening,
• wherein the mist-like charged particles are moved toward the electrostatic latent image support passing through the laminar flow of the gas and the opening of the mist supply passage to adhere to the electrostatic latent image support and develop the electrostatic latent image.