# US 5,708,939 A · Developing apparatus and process for an electrophotographic process > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,708,939 A - Document ID: US5708939A - Status: Granted - Kind: A - Application number: 08/438,491 - Filed: 1995-05-10 - Granted: 1998-01-13 - Earliest claimed: 1994-05-16 - Assignees: Hitachi, Ltd. - Inventors: Akiko Oikawa; Toshiya Satoh; Toru Miyasaka - Web page: https://patentgrep.com/patent/US5708939A ## CPC - G03G 15/0887: {Arrangements for conveying and conditioning developer in the developing unit, e.g. agitating, removing impurities or humidity} - G03G 15/0855: {the concentration being measured by optical means} - G03G 15/0865: {Arrangements for supplying new developer} - G03G 15/0877: {Arrangements for metering and dispensing developer from a developer cartridge into the development unit} - G03G 15/0891: {for conveying or circulating developer, e.g. augers} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract An image forming apparatus for an electrophotographic process utilizes an agglomerate of toner powder so as to avoid scattering of toner powder. When the agglomerate is crushed or de-agglomerated to fine toner powder, only toner powder having a proper particle size for electrophotography is selected by a mesh member through which the toner must pass. The process can be utilized for a single component toner developing system and a component toner developing system. ## Claims ### Claim 1 A developing apparatus for an electrophotographic process which comprises: a photoconductor; a charger for uniformly charging the surface of the photoconductor; an exposer for forming a latent electrostatic image on the surface of the charged photoconductor; and a developing unit for visualizing the latent electrostatic image by causing fine toner powder to adhere to the latent electrostatic image, wherein the developing unit comprises: (a) de-agglomerate means for de-agglomerating toner agglomerate to form said fine toner powder, and (b) classifying means for classifying and selecting toner powder usable for development according to particle size. ### Claim 2 (depends on 1) The developing apparatus according to claim 1, wherein the toner agglomerate is a solid member. ### Claim 3 A developing apparatus for an electrophotographic process which comprises: a photoconductor; a charger for uniformly charging the surface of the photoconductor; an exposer for forming a latent electrostatic image on the charged surface of the photoconductor; and a developing unit for visualizing the latent electrostatic image by causing fine toner powder to adhere to the latent electrostatic image, wherein the developing unit comprises: (a) supply means for supplying a toner agglomerate, (b) de-agglomerate means for de-agglomerating the toner agglomerate to form said fine toner powder, and (c) classifying means for classifying and selecting toner powder usable for development according to particle size. ### Claim 4 (depends on 3) The developing apparatus according to claim 3, wherein the toner agglomerate is a solid member. ### Claim 5 (depends on 3) The developing apparatus according to claim 3, wherein a void fraction .epsilon.(%) is 5 to 80, where the void fraction is a volume of the toner agglomerate occupying a space per unit volume. ### Claim 6 (depends on 3) The developing apparatus according to claim 3, wherein a void fraction .epsilon.(%) is 20 to 70, where the void fraction is a volume of the toner agglomerate occupying a space per unit volume. ### Claim 7 (depends on 3) The developing apparatus according to claim 3, wherein a void fraction .epsilon.(%) is 40 to 60, where the void fraction is a volume of the toner agglomerate occupying a space per unit volume. ### Claim 8 (depends on 3) The developing apparatus according to claim 3, wherein the de-agglomeration means includes at least one rotating wing for crushing the toner agglomerate. ### Claim 9 (depends on 3) The developing apparatus according to claim 3, wherein said de-agglomeration means comprises a rotating member having a predetermined surface roughness and pressure means for biasing the toner agglomerate into contact with the rotating member. ### Claim 10 (depends on 3) The developing apparatus according to claim 3, wherein the developing unit operates in accordance with a non-magnetic one component toner method. ### Claim 11 (depends on 3) The developing apparatus according to claim 3, wherein the developing unit operates in accordance with a two component toner method utilizing a magnetic brush. ### Claim 12 An electrophotographic process for an image forming apparatus which comprises the steps of: preparing an agglomerate of toner powder; supplying the agglomerate to a developing unit; de-agglomerating the agglomerate in the developing unit to form fine toner powder; and classifying and selecting toner powder usable for development according to particle size. ### Claim 13 (depends on 12) The electrophotographic process according to claim 12, wherein the step of preparing an agglomerate of toner powder provides a solid member as the agglomerate of toner powder. ### Claim 14 (depends on 12) The electrophotographic process according to claim 12, wherein the developing unit is part of a developing apparatus including a photoconductor, a charger for uniformly charging the surface of the photoconductor, an exposer for forming a latent electrostatic image on the surface of the charged photoconductor, and the developing unit enables visualizing of the latent electrostatic image by causing fine toner powder to adhere to the latent electrostatic image. ### Claim 15 (depends on 12) The electrophotographic process according to claim 12, wherein the developing unit of the electrophotographic process includes a photoconductor, a charger for uniformly charging the surface of the photoconductor, an exposer for forming a latent electrostatic image on the surface of the charged photoconductor, and the developing unit enables visualizing of the latent electrostatic image by causing fine toner powder to adhere to the latent electrostatic image. ### Claim 16 A developing apparatus for an electrophotographic process which comprises: a photoconductor; a charger for uniformly charging the surface of the photoconductor; an exposer for forming a latent electrostatic image on the surface of the charged photoconductor; and a developing unit for visualizing the latent electrostatic image by causing fine toner powder to adhere the latent electrostatic image, wherein the developing unit comprises: (a) de-agglomerate means for de-agglomerating toner agglomerate to form said fine toner powder, (b) classifying means for classifying and selecting toner powder usable for development according to particle size, and (c) collection means for collecting ultra-fine toner powder which was not classified and selected as toner powder usable for development in the developing apparatus. ### Claim 17 A developing apparatus for an electrophotographic process which comprises: a photoconductor; a charger for uniformly charging the surface of the photoconductor; an exposer for forming a latent electrostatic image on the surface of the charged photoconductor; and a developing unit for visualizing the latent electrostatic image by causing fine toner powder to adhere the latent electrostatic image, wherein the developing unit comprises: (a) supply means for supplying a toner agglomerate, (b) de-agglomerate means for de-agglomerating toner agglomerate to form said fine toner powder, (c) classifying means for classifying and selecting toner powder usable for development according to particle size, and (d) collection means for collecting ultra-fine toner powder which was not classified and selected as toner powder usable for development in the developing apparatus. ### Claim 18 An electrophotographic process for an imaging forming apparatus having a photoconductor, a charger for uniformly charging the surface of the photoconductor, an exposer for forming a latent electrostatic image on the surface of the charged photoconductor, and a developing unit for visualizing the latent electrostatic image by causing fine toner powder to adhere to the latent electrostatic image, the developing unit including de-agglomerate means for de-agglomerating toner agglomerate to form the fine toner powder, and classifying means for classifying and selecting toner powder usable for development according to particle size, the electrophotographic process including the steps of: de-agglomerating the toner agglomerate to form the fine toner powder utilizing the de-agglomerate means; and classifying and selecting toner powder usable for development according to particle size utilizing the classifying means. ### Claim 19 (depends on 18) The electrophotographic process according to claim 18, further comprising the step of visualizing the latent electrostatic image by causing fine toner powder to adhere to the latent electrostatic image. ### Claim 20 (depends on 18) The electrophotographic process according to claim 18, wherein the toner agglomerate is a solid member. ### Claim 21 An electrophotographic process for an image forming apparatus having a photoconductor, a charger for uniformly charging the surface of the photoconductor, an exposer for forming a latent electrostatic image on the surface of the charged photoconductor, and a developing unit for visualizing the latent electrostatic image by causing fine toner powder to adhere to the latent electrostatic image, the developing unit including supply means for supplying a toner agglomerate, de-agglomerate means for de-agglomerating the toner agglomerate to form the fine toner powder, and classifying means for classifying and selecting toner powder usable for development according to particle size, the electrophotographic process comprising the steps of: supplying toner agglomerate utilizing the supply means; de-agglomerating the toner agglomerate to form the fine toner powder utilizing the de-agglomerate means; and classifying and selecting the toner powder usable for development according to particle size utilizing the classifying means. ### Claim 22 (depends on 21) The electrophotographic process according to claim 21, further comprising the step of visualizing the latent electrostatic image by causing the fine toner powder to adhere to the latent electrostatic image. ### Claim 23 (depends on 21) The electrophotographic process according to claim 21, wherein the toner agglomerate is a solid member. ### Claim 24 (depends on 21) The electrophotographic process according to claim 21, wherein a void fraction .epsilon.(%) is 5 to 80, where the void fraction is a volume of the toner agglomerate occupying a space per unit volume. ### Claim 25 (depends on 21) The electrophotographic process according to claim 21, wherein a void fraction .epsilon.(%) is 20 to 70, where the void fraction is a volume of the toner agglomerate occupying a space per unit volume. ### Claim 26 (depends on 21) The electrophotographic process according to claim 21, wherein a void fraction .epsilon.(%) is 40 to 60, where the void fraction is a volume of the toner agglomerate occupying a space per unit volume. ### Claim 27 (depends on 21) The electrophotographic process according to claim 21, wherein the step of de-agglomerating means includes at least one rotating wing for crushing the toner agglomerate. ### Claim 28 (depends on 21) The electrophotographic process according to claim 21, wherein the de-agglomeration means comprises a rotating member having a predetermined surface roughness and pressure means for biasing the toner agglomerate into contact with the rotating member. ### Claim 29 (depends on 21) The electrophotographic process according to claim 21, wherein the developing unit operates in accordance with a non-magnetic one component toner method. ### Claim 30 (depends on 21) The electrophotographic process according to claim 21, wherein the developing unit operates in accordance with a two component toner method utilizing a magnetic brush.