# US 7,194,229 B2 · Method and apparatus for forming superimposed toner images of a plurality of colors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,194,229 B2 - Document ID: US7194229B2 - Status: Granted - Kind: B2 - Application number: 11/234,089 - Filed: 2005-09-26 - Published: 2006-03-30 - Granted: 2007-03-20 - Earliest claimed: 2004-09-28 - Assignees: Kabushiki Kaisha Toshiba - Inventors: Koichi Ishii - Web page: https://patentgrep.com/patent/US7194229B2 ## CPC - G03G 15/11: Removing excess liquid developer, e.g. by heat - G03G 15/0157: {with special treatment between monocolour image formation} - G03G 15/0173: {plural rotations of recording member to produce multicoloured copy, e.g. rotating set of developing units (G03G15/0163 takes precedence)} - G03G 2215/018: Linearly moving set of developing units, one at a time adjacent the recording member - G03G 2215/0187: Multicoloured toner image formed on the recording member - G03G 2221/0036: Oil and other liquid matter - G03G 2221/0063: Cleaning device for foreign matter separate from residual toner cleaning device - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract When superimposing toner images of a plurality of colors on an image supporting member to form a color image, a free phase ion in a precedent image is removed without distorting the toner image precedently formed on the image supporting member, thereby improving reproducibility of image dots of the toner images having second and subsequent colors to obtain a high-definition color image with high contrast. ## Claims ### Claim 1 A color image forming apparatus comprising: an image supporting member which includes a photoconductive layer configured to hold an electrostatic latent image; a first image forming section, arranged around the image supporting member, which forms and visualizes an electrostatic latent image on the photoconductive layer to form a first developed image, the first image forming section having a charging device which gives a first potential to the photoconductive layer, an exposure device which forms a first electrostatic latent image corresponding to an image of a first color on the photoconductive layer, and a development device which supplies a developer of the first color to the first electrostatic latent image to form a first developed image; a second image forming section, arranged around the image supporting member, which forms and visualizes an electrostatic latent image formed on the photoconductive layer to form a second developed image, the second image forming section having a charging device which gives a second potential to the photoconductive layer, the charging device electrostatically fixing the developer of the first color to the photoconductive layer and applying potential to the photoconductive layer so as to form a second electrostatic latent image to the photoconductive layer, an exposure device which forms the second electrostatic latent image corresponding to an image of a second color on the photoconductive layer, and a development device which supplies a developer of the second color to the second electrostatic latent image to form a second developed image at least partially overlapping the first developed image; and a carrier liquid quantity reducing device which is arranged around the image supporting member, and removes part of a carrier liquid contained in the first developed image formed by the first image forming section after a second charging with the charging device of the second image forming section and before the second developed image is formed by the second image forming section. ### Claim 2 (depends on 1) The color image forming apparatus according to claim 1, wherein the second image forming section removes the carrier liquid supplied by the first image forming section, during second and subsequent revolutions of the image supporting member after the first developed image is formed by the first image forming section. ### Claim 3 (depends on 1) The color image forming apparatus according to claim 1, wherein the carrier liquid quantity reducing device includes a roller member formed to selectively come into contact with a surface of the image supporting member. ### Claim 4 (depends on 1) The color image forming apparatus according to claim 1, wherein the carrier liquid quantity reducing device includes a blower device which provides an air current to a surface of the image supporting member. ### Claim 5 (depends on 4) The color image forming apparatus according to claim 4, wherein the blower device does not come into contact with the surface of the image supporting member. ### Claim 6 (depends on 1) The color image forming apparatus according to claim 1, wherein the charging device and the exposure device are configured to be shared in the second image forming section and the first image forming section. ### Claim 7 A color image forming apparatus which forms a second toner image on a first toner image formed on an image supporting member in a superimposing manner by using a liquid carrier containing toner particles and a carrier liquid, comprising: a charging device which charges a surface of the image supporting member on which the first toner image is formed, and the charging device preventing the first toner image from being damaged, and applying potential to the image supporting member so as to form the second toner image on the image supporting member; a carrier liquid quantity reducing device which reduces the carrier liquid on the charged surface of the image supporting member; and an image forming unit which includes an exposure device and a development device, the exposure device forming an electrostatic latent image on the surface of the image supporting member from which the carrier liquid is reduced, the development device developing the electrostatic latent image to form the second toner image, the carrier liquid quantity reducing device being configured to reduce the carrier liquid from the first toner image before the second toner image is formed. ### Claim 8 (depends on 7) The color image forming apparatus according to claim 7, wherein the image forming unit removes the carrier liquid contained in the first toner image during second and subsequent revolutions of the image supporting member. ### Claim 9 (depends on 7) The color image forming apparatus according to claim 7, wherein the carrier liquid quantity reducing device includes a roller member formed to selectively come into contact with the surface of the image supporting member. ### Claim 10 (depends on 7) The color image forming apparatus according to claim 7, wherein the carrier liquid quantity reducing device includes a roller member formed to selectively come into contact with the surface of the image supporting member. ### Claim 11 (depends on 7) The color image forming apparatus according to claim 7, wherein the charging device and the exposure device are configured to be shared in forming of the second toner image and forming of the first toner image. ### Claim 12 An image forming method comprising: charging a surface of an image supporting member; forming a first electrostatic latent image on the image supporting member; supplying a first liquid developer containing toner particles and a carrier liquid to the first electrostatic latent image on the image supporting member to form a first toner image; charging the surface of the image supporting member including the first toner image to electrostatically fix the first toner image on the image supporting member and to form a second electrostatic latent image on the image supporting member; reducing the carrier liquid in the first toner image on the image supporting member; forming a second electrostatic latent image on the first toner image on the image supporting member; and supplying a second liquid developer containing toner particles and a carrier liquid to the second electrostatic latent image onto the first toner image to form a second toner image in a superimposing manner after the reducing of the carrier liquid. ### Claim 13 (depends on 12) The image forming method according to claim 12, further comprising: charging a surface of the image supporting member including the first and second toner images; forming a second electrostatic latent image on the image supporting member after the charging of the image supporting member including the first and second toner images; reducing the carrier liquid in the second toner image having a second charging potential given thereto in the charging of the image supporting member including the first and second toner images; and supplying a third liquid developer containing toner particles and a carrier liquid onto the first and second toner images to form a third toner image in a superimposing manner after the reducing of the carrier liquid in the second toner image. ### Claim 14 (depends on 12) The image forming method according to claim 12, wherein the charging is performed at a point on the surface of the image supporting member.