# US 2019/0317430 A1 · Developing device and image forming device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0317430 A1 - Document ID: US20190317430A1 - Status: Published application - Kind: A1 - Application number: 16/455,033 - Filed: 2019-06-27 - Published: 2019-10-17 - Earliest claimed: 2016-12-27 - Assignees: Hewlett-Packard Development Company, L.P. - Applicants: Hewlett-Packard Development Company, L.P. - Inventors: Kiyofumi MORIMOTO - Web page: https://patentgrep.com/patent/US20190317430A1 ## CPC - G03G 15/0942: {with means for preventing toner scattering from the magnetic brush, e.g. magnetic seals} - G03G 9/10: characterised by carrier particles - G03G 15/0815: {characterised by the developer handling means after the developing zone and before the supply, e.g. developer recovering roller} - G03G 15/163: {using the force produced by an electrostatic transfer field formed between the second base and the electrographic recording member, e.g. transfer through an air gap} - G03G 21/1676: {for the developer unit} - G03G 15/0921: {Details concerning the magnetic brush roller structure, e.g. magnet configuration} - G03G 21/206: {Conducting air through the machine, e.g. for cooling, filtering, removing gases like ozone} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract A developing device includes a latent image carrier to form an electrostatic latent image is formed on a surface of the latent image carrier, a developing agent carrier to carry a developing agent including toner on a surface of the developing agent carrier, the developing agent carrier facing the latent image carrier, and a roll-shaped member facing the developing agent carrier to form a first gap and facing the latent image carrier to form a second gap, to form a suction air flow through the first gap and the second gap, to suction toner particles scattered to the first gap between the roll-shaped member and the developing agent carrier and the second gap between the roll-shaped member and the latent image carrier. ## Claims ### Claim 1 A developing device comprising: a latent image carrier to form an electrostatic latent image on a surface of the latent image carrier; a developing agent carrier to carry a developing agent including toner on a surface of the developing agent carrier, the developing agent carrier facing the latent image carrier; and a roll-shaped member facing the developing agent carrier to form a first gap and facing the latent image carrier to form a second gap, to form a suction air flow through the first gap and the second gap, to suction toner particles scattered to the first gap between the roll-shaped member and the developing agent carrier and the second gap between the roll-shaped member and the latent image carrier. ### Claim 2 (depends on 1) The developing device of claim 1, wherein a first interval (interval A) of the first gap between the roll-shaped member and the developing agent carrier and a second interval (interval B) of the second gap between the roll-shaped member and the latent image carrier satisfy a relation of 0.5 mm≤interval A≤1.1 mm and 0≤interval B/interval A≤0.9. ### Claim 3 (depends on 2) The developing device of claim 2, wherein the developing agent carrier is to transfer the developing agent to a developing area where the developing agent carrier faces the latent image carrier to transfer the developing agent to develop the latent image on the latent image carrier, and wherein a transfer amount of the developing agent that is transferred to the developing area from the developing agent carrier is 300 g/m2 or more and 700 g/m2 or less. ### Claim 4 (depends on 1) The developing device of claim 1, wherein the developing device further comprises a carrying amount regulating member to regulate a carrying amount of the developing agent that is carried on the developing agent carrier. ### Claim 5 (depends on 2) The developing device of claim 2, wherein the second interval is more than 0 mm and 1.0 mm or less. ### Claim 6 (depends on 2) The developing device of claim 2, further comprising a developing case to accommodate the developing agent; wherein the developing agent carrier is to carry a developing agent from the developing case; and wherein a third interval (interval C) between the developing agent carrier and the developing case satisfies a relation of: interval C/interval A≥1.4 at least in a proximity of the roll-shaped member. ### Claim 7 (depends on 1) The developing device of claim 1, wherein the developing agent carrier comprises: a developing sleeve to form a surface layer of the developing agent carrier; and a magnet to be disposed inside the developing sleeve and includes a plurality of magnetic poles in a circumferential direction, wherein the plurality of magnetic poles includes: a first magnetic pole adjacent to a circumferential direction, and a second magnetic pole having a polarity opposite to the first magnetic pole, and wherein the roll-shaped member is positioned at a gap between the first magnetic pole and the second magnetic pole. ### Claim 8 (depends on 7) The developing device of claim 7, wherein the roll-shaped member is positioned within a range of ±20°, in a circumferential direction of the developing agent carrier, from a position in which an absolute value of a magnetic force component in a normal line direction of the developing agent carrier becomes a minimum value in a gap between the first magnetic pole and the second magnetic pole. ### Claim 9 (depends on 1) The developing device of claim 1, wherein the roll-shaped member is made of a non-magnetic member. ### Claim 10 (depends on 1) The developing device of claim 1, wherein an arithmetic average roughness Ra of a surface of the roll-shaped member is 10 μm or less. ### Claim 11 (depends on 1) The developing device of claim 1, wherein an end of the roll-shaped member is interleaved to a cylindrical member that is in contact with a surface of the latent image carrier. ### Claim 12 (depends on 1) The developing device of claim 1, further comprising: a bias applying unit to apply a bias voltage to the roll-shaped member. ### Claim 13 (depends on 12) The developing device of claim 12, wherein the bias applying unit is to apply, to the roll-shaped member, a bias voltage having an absolute value larger than a bias voltage applied to the developing agent carrier and a bias voltage having a smaller absolute value than a surface potential of the latent image carrier. ### Claim 14 (depends on 1) The developing device of claim 1, wherein the developing agent includes a carrier; and an average particle diameter of the carrier is 20 μm or more and 40 μm or less. ### Claim 15 An image forming apparatus comprising: a developing device including a latent image carrier to form an electrostatic latent image on a surface of the latent image carrier; a developing agent carrier to carry a developing agent including toner on a surface of the developing agent carrier, the developing agent carrier facing the latent image carrier; and a roll-shaped member facing developing agent carrier to form a first gap and facing the latent image carrier to form a second gap, to form a suction air flow through the first gap and the second gap, to suction toner particles scattered to the first gap between the roll-shaped member and the developing agent carrier and the second gap between the roll-shaped member and the latent image carrier.