# US 7,611,816 B2 · Process for producing toner particles > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,611,816 B2 - Document ID: US7611816B2 - Status: Granted - Kind: B2 - Application number: 11/459,613 - Filed: 2006-07-24 - Published: 2008-10-02 - Granted: 2009-11-03 - Earliest claimed: 2005-07-29 - Assignees: Canon Kabushiki Kaisha - Inventors: Yoshinori Tuji; Hidekazu Fumita; Minoru Omura - Web page: https://patentgrep.com/patent/US7611816B2 ## CPC - G03G 9/0815: {Post-treatment} - G03G 9/0804: {whereby the components are brought together in a liquid dispersing medium} - G03G 9/0817: {Separation; Classifying} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract In a process for producing toner particles through granulation by a wet process, a process for producing toner particles is provided that enables reduction of water content in wet toner particle cakes obtained by separating toner particles from a toner particle dispersion in a good efficiency, followed by washing, and enables efficient wash-away of impurities remaining on the toner particle surfaces so as to promise superior image characteristics. The toner particles are produced through a filtering step in which a slurry which contains toner particles is subjected to solid-liquid separation by means of a belt filter having a pressing aeration means which carries out aeration with pressing, to form wet toner particle cakes. ## Claims ### Claim 1 A process for producing toner particles in a liquid dispersion medium; the process being a toner particle production process comprising: (a) forming a slurry which contains toner particles; and (b) subjecting the slurry to a filtering step for solid-liquid separation by means of a belt filter having a pressing aeration means which carries out aeration with pressing, to form wet toner particle cakes, wherein said filtering step which forms the wet toner particle cakes comprises the steps, in sequence, of (i) dehydrating the slurry which contains toner particles, to obtain toner particle cakes; (ii) washing the resultant toner particle cakes to obtain wash-water-containing toner particle cakes; and (iii) subjecting the wash-water-containing toner particle cakes to aeration with pressure by said pressing aeration means to obtain said wet toner particle cakes. ### Claim 2 (depends on 1) The process for producing toner particles according to claim 1, which comprises a drying step for drying the wet toner particle cakes obtained through said filtering step. ### Claim 3 (depends on 2) The process for producing toner particles according to claim 2, wherein said drying step is the step of airborne drying in which said wet toner particle cakes are dispersed in hot-air streams and in the form of powder particles so as to be dried while being sent in flows parallel with the hot-air streams. ### Claim 4 (depends on 1) The process for producing toner particles according to claim 1, wherein said pressing aeration means has a perforated portion with holes through which at least aeration is performed, and has an elastic portion having elasticity, which surrounds the perforated portion and is so provided as to come into contact with a filter cloth of said belt filter at the time of aeration. ### Claim 5 (depends on 4) The process for producing toner particles according to claim 4, wherein a member constituting said elastic portion is formed of a soft rubber, and has rubber hardness F (degree) of: 10≦F≦40. ### Claim 6 (depends on 5) The process for producing toner particles according to claim 5, wherein said member constituting said elastic portion is formed of chloroprene rubber. ### Claim 7 (depends on 4) The process for producing toner particles according to claim 4, wherein compressed air is passed through said perforated portion. ### Claim 8 (depends on 7) The process for producing toner particles according to claim 7, wherein said compressed air has pressure P1 (kPa) of: 10≦P1≦900. ### Claim 9 (depends on 7) The process for producing toner particles according to claim 7, wherein said perforated portion affords aeration rate G per unit area and unit time (m3/m2·s) of: 0.01≦G≦0.50. ### Claim 10 (depends on 4) The process for producing toner particles according to claim 4, wherein, at the time of aeration, said elastic portion is kept in pressure contact with said filter cloth so that the air passed through said perforated portion does not leak from the pressing aeration part; the pressure contact being at pressure P2 (kPa) of: 20≦P2≦1,000. ### Claim 11 (depends on 1) The process for producing toner particles according to claim 1, wherein said liquid dispersion medium for dispersing the toner particles therein is an aqueous dispersion medium. ### Claim 12 (depends on 1) The process for producing toner particles according to claim 1, wherein said toner particles contained in said slurry are toner particles formed by polymerizing in an aqueous medium a polymerizable monomer composition containing at least a polymerizable monomer and a colorant. ### Claim 13 (depends on 12) The process for producing toner particles according to claim 12, wherein said colorant is constituted of a non-magnetic material. ### Claim 14 (depends on 12) The process for producing toner particles according to claim 12, wherein said colorant is a magnetic fine powder having been treated with a silane coupling agent. ### Claim 15 (depends on 1) The process for producing toner particles according to claim 1, wherein said belt filter is a vacuum belt filter in which, at the time of vacuum filtration, a filter cloth and a vacuum tray do not rub against each other in the state of being evacuated. ### Claim 16 (depends on 1) The process for producing toner particles according to claim 1, wherein said belt filter is a filter cloth intermittent movement type belt filter. ### Claim 17 (depends on 16) The process for producing toner particles according to claim 16, wherein said pressing aeration means is capable of coming into contact with and separating from the wet toner particle cakes, and said pressing aeration means interlocks with intermittent movement of the filter cloth of said filter cloth intermittent movement type belt filter. ### Claim 18 (depends on 4) The process for producing toner particles according to claim 4, wherein said elastic portion has width D (mm) around the perforated portion, of: 30≦D≦300. ### Claim 19 (depends on 1) The process for producing toner particles according to claim 1, wherein said wet toner particle cakes after the filtering step making use of said belt filter has a water content of 30% or less. ### Claim 20 (depends on 1) The process for producing toner particles according to claim 1, wherein the matter to be filtered that is to be fed to the filtering step is a slurry containing the toner particles having been subjected to defoaming treatment in a defoaming step. ### Claim 21 (depends on 20) The process for producing toner particles according to claim 20, wherein said defoaming treatment is the step of feeding to an evacuatable container the slurry containing the toner particles, to carry out vacuum treatment. ### Claim 22 (depends on 20) The process for producing toner particles according to claim 20, wherein said vacuum treatment is carried out under a reduced pressure of from 5 to 50 kPa. ### Claim 23 (depends on 20) The process for producing toner particles according to claim 20, wherein said defoaming treatment is the step of so treating the slurry as to satisfy the following relationship of: 1.05≦A/C≦3.00 where the bulk density of the toner-particle-containing slurry before defoaming treatment is represented by C (kg/l), and the bulk density of the toner-particle-containing slurry after defoaming treatment by A (kg/l).