# US 5,702,858 A · Toner > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,702,858 A - Document ID: US5702858A - Status: Granted - Kind: A - Application number: 08/679,130 - Filed: 1996-07-12 - Granted: 1997-12-30 - Earliest claimed: 1994-04-22 - Assignees: Matsushita Electric Industrial Co., Ltd. - Inventors: Yasuhito Yuasa; Noriaki Hirota; Akinori Toyoda; Hideki Tatematsu - Web page: https://patentgrep.com/patent/US5702858A ## CPC - G03G 15/1605: {using at least one intermediate support (G03G15/1625 takes precedence)} - G03G 9/09708: {Inorganic compounds} - G03G 9/09716: {treated with organic compounds} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract Toner used for electrophotographic development includes additives such as inorganic fine particles, having a particular particle diameter and specific surface area, and hydrophobic silica having a particular specific surface area and surface treatment, so that the toner can provide images of high quality without generating photoconductor filming. The toner is applied to the electrophotographic method including the developing step of forming electrostatic latent images on a photoconductor containing a stationary magnet, magnetically attracting the toner to the surface of the photoconductor in a toner sump, and collecting toner at a non-image section by an electrode roller; the transferring step of transferring the toner to transfer paper; the cleaning step of removing residual toner left on the photoconductor in the transferring step; and the recycling step of recycling the residual toner. Toner used for an electrophotographic method using an intermediate transfer member includes additives such as inorganic fine particles, having a particular particle diameter and specific surface area, arid hydrophobic silica having a particular specific surface area and surface treatment, so that the toner can provide images of high quality and high transfer efficiency without generating photoconductor and intermediate transfer member filming. ## Claims ### Claim 1 A toner comprising toner base particles comprising a binder resin, and an additive comprising inorganic fine particles of 0.05-4 .mu.m volume-average particle diameter and 0.1-40 m.sup.2 /g specific surface area, and negatively charged hydrophobic silica fine particles having 50-350 m.sup.2 /g specific surface area and surface treated with a silicone oil, wherein the inorganic fine particles are prepared by a hydrothermal method or an oxalate thermal decomposition method and comprise at least one compound selected from the group consisting CaSiO.sub.3, LaCrO.sub.3, AlPO.sub.4, NbP .sub.3 O.sub.4, LaFeO.sub.3, LiNbO.sub.3, SrTiO.sub.3, BaTiO.sub.3, MgTiO.sub.3, AlTiO.sub.3, CaTiO.sub.3, PbTiO.sub.3, FeTiO.sub.3, SrZrO.sub.3, BaZrO.sub.3, MgZrO.sub.3, AlZrO.sub.3, CaZrO.sub.3, PbZrO.sub.3, MnSiO.sub.3, MgSiO.sub.3, CaSiO.sub.3, MoO.sub.2, SnO.sub.2, ZnO.sub.2, MgO.sub.2, NiO, V.sub.2 O.sub.5, Nb.sub.2 O.sub.5, WO.sub.2, Nb.sub.2 O.sub.3 --TiO.sub.2, Ta.sub.2 O.sub.5 --TiO.sub.2, and V.sub.2 O.sub.5 --ZnO.sub.2. ### Claim 2 (depends on 1) The toner as in claim 1, wherein the inorganic fine particles are prepared by a hydrothermal method selected from the group consisting of a hydrothermal oxidation method, a hydrothermal precipitation method, a hydrothermal composition method, a hydrothermal dispersion method, a hydrothermal crystallization method, a hydrothermal hydrolysis method, a hydrothermal agitate-mixing method, and a hydrothermal mechano-chemical method. ### Claim 3 (depends on 1) The toner as in claim 1, wherein the inorganic fine particles are titanate fine particles prepared by a hydrothermal method or zirconate fine particles prepared by a hydrothermal method. ### Claim 4 (depends on 1) The toner as in claim 1, wherein the inorganic fine particles are titanate fine particles prepared by an oxalate thermal decomposition method or zirconate fine particles prepared by an oxalate thermal decomposition method. ### Claim 5 (depends on 1) The toner as in claim 1, wherein the inorganic fine particles are present in an amount of 0.1-5.0 weight parts relative to 100 weight parts of the toner base particles. ### Claim 6 (depends on 1) The toner as in claim 1, wherein the negatively charged hydrophobic silica fine particles are present in an amount of 0.1-5.0 weight parts relative to 100 weight parts of the toner base particles. ### Claim 7 (depends on 1) The toner as in claim 1, wherein the inorganic fine particles have oppositely chargeable properties with respect to the toner base particles, and have from +3 .mu.C/g to +30 .mu.C/g charge amount with respect to said toner base particles. ### Claim 8 (depends on 1) The toner as in claim 1, further comprising at least one magnetic component. ### Claim 9 (depends on 1) The toner as in claim 1, further comprising at least one pigment. ### Claim 10 An electrophotographic method which comprises: forming electrostatic latent images on a movable photoconductor containing a stationary magnet, magnetically attracting a toner to a surface of said photoconductor positioned in a toner sump, said toner comprising a binder resin, and an additive comprising inorganic fine particles of 0.05-4 .mu.m volume-average particle diameter and 0.1-40 m.sup.2 /g specific surface area, and negatively charged hydrophobic silica fine particles having 50-350 m.sup.2 /g specific surface area and surface treated with a silicone oil, holding said toner on the surface of said photoconductor, shifting said photoconductor so as to face a toner collecting electrode roller which has an internal magnet and is positioned at a predetermined position from the surface of said photoconductor, and leaving said toner at an image section of said photoconductor and collecting said toner at a non-image section of said photoconductor by said toner collecting electrode roller to develop an image; transferring said toner from said photoconductor to transfer paper by electrostatic force; and removing residual toner left on said photoconductor from said transferring step to clean the photoconductor, wherein the inorganic fine particles are prepared by a hydrothermal method or an oxalate thermal decomposition method and comprise at least one compound selected from the group consisting CaSiO.sub.3, LaCrO.sub.3, AlPO.sub.4, NbP .sub.3 O.sub.4, LaFeO.sub.3, LiNbO.sub.3, SrTiO.sub.3, BaTiO.sub.3, MgTiO.sub.3, AlTiO.sub.3, CaTiO.sub.3, PbTiO.sub.3, FeTiO.sub.3, SrZrO.sub.3, BaZrO.sub.3, MgZrO.sub.3, AlZrO.sub.3, CaZrO.sub.3, PbZrO.sub.3, MnSiO.sub.3, MgSiO.sub.3, CaSiO.sub.3, MoO.sub.2, SnO.sub.2, ZnO.sub.2, MgO.sub.2, NiO, V.sub.2 O.sub.5, Nb.sub.2 O.sub.5, WO.sub.2, Nb.sub.2 O.sub.3 --TiO.sub.2, Ta.sub.2 O.sub.5 --TiO.sub.2, and V.sub.2 O.sub.5 --ZnO.sub.2. ### Claim 11 (depends on 10) The electrophotographic method as in claim 10, wherein the inorganic fine particles are prepared by a hydrothermal method selected from the group consisting of a hydrothermal oxidation method, a hydrothermal precipitation method, a hydrothermal composition method, a hydrothermal dispersion method, a hydrothermal crystallization method, a hydrothermal hydrolysis method, a hydrothermal agitate-mixing method, and a hydrothermal mechano-chemical method. ### Claim 12 (depends on 10) The electrophotographic method as in claim 10, wherein the inorganic fine particles are titanate fine particles prepared by a hydrothermal method or zirconate fine particles prepared by a hydrothermal method. ### Claim 13 (depends on 10) The electrophotographic method as in claim 10, wherein the inorganic fine particles are titanate fine particles prepared by an oxalate thermal decomposition method or zirconate fine particles prepared by an oxalate thermal decomposition method. ### Claim 14 (depends on 10) The electrophotographic method as in claim 10, wherein the inorganic fine particles are present in an amount of 0.1-5.0 weight parts relative to 100 weight parts of the toner base particles. ### Claim 15 (depends on 10) The electrophotographic method as in claim 10, wherein the negatively charged hydrophobic silica fine particles are present in an amount of 0.1-5.0 weight parts relative to 100 weight parts of the toner base particles. ### Claim 16 (depends on 10) The electrophotographic method as in claim 10, wherein the inorganic fine particles have oppositely chargeable properties with respect to the toner base particles, and have from +3 .mu.C/g to +30 .mu.C/g charge amount with respect to said toner base particles. ### Claim 17 (depends on 10) The electrophotographic method as in claim 10, wherein the toner further comprises at least one magnetic component. ### Claim 18 (depends on 10) The electrophotographic method as in claim 10, wherein the toner further comprises at least one pigment. ### Claim 19 An electrophotographic method which comprises: forming electrostatic latent images on a movable photoconductor containing a stationary magnet, magnetically attracting a toner to a surface of said photoconductor positioned in a toner sump, said toner comprising a binder resin, and an additive comprising inorganic fine particles of 0.05-4 .mu.m volume-average particle diameter and 0.1-40 m.sup.2 /g specific surface area, and negatively charged hydrophobic silica fine particles having 50-350 m.sup.2 /g specific surface area and surface treated with a silicone oil, holding said toner on the surface of said photoconductor, shifting said photoconductor so as to face a toner collecting electrode roller which has an internal magnet and is positioned at a predetermined position from the surface of said photoconductor, and leaving said toner at an image section of said photoconductor and collecting said toner at a non-image section of said photoconductor by said toner collecting electrode roller to develop an image; passing transfer paper between said photoconductor and a conductive elastic roller which is in contact with said photoconductor, and transferring said toner from said photoconductor to said transfer paper by transfer bias voltage applied to said conductive elastic roller; and subsequently removing residual toner left on said photoconductor in said transferring step to clean the photoconductor, wherein the inorganic fine particles are prepared by a hydrothermal method or an oxalate thermal decomposition method and comprise at least one compound selected from the group consisting of CaSiO.sub.3, LaCrO.sub.3, AlPO.sub.4, NbP .sub.3 O.sub.4, LaFeO.sub.3, LiNbO.sub.3, SrTiO.sub.3, BaTiO.sub.3, MgTiO.sub.3, AlTiO.sub.3, CaTiO.sub.3, PbTiO.sub.3, FeTiO.sub.3, SrZrO.sub.3, BaZrO.sub.3, MgZrO.sub.3, AlZrO.sub.3, CaZrO.sub.3, PbZrO.sub.3, MnSiO.sub.3, MgSiO.sub.3, CaSiO.sub.3, MoO.sub.2, SnO.sub.2, ZnO.sub.2, MgO.sub.2, NiO, V.sub.2 O.sub.5, Nb.sub.2 O.sub.5, WO.sub.2, Nb.sub.2 O.sub.3 --TiO.sub.2, Ta.sub.2 O.sub.5 --TiO.sub.2, and V.sub.2 O.sub.5 --ZnO.sub.2. ### Claim 20 (depends on 19) The electrophotographic method as in claim 19, wherein the inorganic fine particles are prepared by a hydrothermal method selected from the group consisting of a hydrothermal oxidation method, a hydrothermal precipitation method, a hydrothermal composition method, a hydrothermal dispersion method, a hydrothermal crystallization method, a hydrothermal hydrolysis method, a hydrothermal agitate-mixing method, and a hydrothermal mechano-chemical method. ### Claim 21 (depends on 19) The electrophotographic method as in claim 19, wherein the inorganic fine particles are titanate fine particles prepared by a hydrothermal method or zirconate fine particles prepared by a hydrothermal method. ### Claim 22 (depends on 19) The electrophotographic method as in claim 19, wherein the inorganic fine particles are titanate fine particles prepared by an oxalate thermal decomposition method or zirconate fine particles prepared by an oxalate thermal decomposition method. ### Claim 23 (depends on 19) The electrophotographic method as in claim 19, wherein the inorganic fine particles are present in an amount of 0.1-5.0 weight parts relative to 100 weight parts of the toner base particles. ### Claim 24 (depends on 19) The electrophotographic method as in claim 19, wherein the negatively charged hydrophobic silica fine particles are present in an amount of 0.1-5.0 weight parts relative to 100 weight parts of the toner base particles. ### Claim 25 (depends on 19) The electrophotographic method as in claim 19, wherein the inorganic fine particles have oppositely chargeable properties with respect to the toner base particles, and have from +3 .mu.C/g to +30 .mu.C/g charge amount with respect to said toner base particles. ### Claim 26 (depends on 19) The electrophotographic method as in claim 19, wherein the conductive elastic roller used in the transferring step comprises a urethane foaming material, to which a conductive additive is added, as an elastic member. ### Claim 27 (depends on 26) The electrophotographic method as in claim 26, wherein the conductive additive is lithium salt. ### Claim 28 (depends on 19) The electrophotographic method as in claim 19, wherein the toner further comprises at least one magnetic component. ### Claim 29 (depends on 19) The electrophotographic method as in claim 19, wherein the toner further comprises at least one pigment. ### Claim 30 The electrophotographic method which comprises: forming electrostatic latent images on a movable photoconductor containing a stationary magnet, magnetically attracting a toner to a surface of said photoconductor positioned in a toner sump, said toner comprising a binder resin, and an additive comprising inorganic fine particles of 0.05-4 .mu.m volume-average particle diameter and 0.1-40 m.sup.2 /g specific surface area, and negatively charged hydrophobic silica fine particles having 50-350 m.sup.2 /g specific surface area and surface treated with a silicone oil, holding said toner on the surface of said photoconductor, shifting said photoconductor so as to face a toner collecting electrode roller which has an internal magnet and is positioned at a predetermined position from the surface of said photoconductor, and leaving said toner at an image section of said photoconductor and collecting said toner at a non-image section of said photoconductor by said toner collecting electrode roller to develop an image; passing transfer paper between said photoconductor and a conductive elastic roller which is in contact with said photoconductor, and transferring said toner from said photoconductor to said transfer paper by transfer bias voltage applied to said conductive elastic roller; removing residual toner left on said photoconductor in said transferring step to clean the photoconductor; and recycling said residual toner in said developing step, wherein the inorganic fine particles are prepared by a hydrothermal method or an oxalate thermal decomposition method and comprise at least one compound selected from the group consisting CaSiO.sub.3, LaCrO.sub.3, AlPO.sub.4, NbP .sub.3 O.sub.4, LaFeO.sub.3, LiNbO.sub.3, SrTiO.sub.3, BaTiO.sub.3, MgTiO.sub.3, AlTiO.sub.3, CaTiO.sub.3, PbTiO.sub.3, FeTiO.sub.3, SrZrO.sub.3, BaZrO.sub.3, MgZrO.sub.3, AlZrO.sub.3, CaZrO.sub.3, PbZrO.sub.3, MnSiO.sub.3, MgSiO.sub.3, CaSiO.sub.3, MoO.sub.2, SnO.sub.2, ZnO.sub.2, MgO.sub.2, NiO, V.sub.2 O.sub.5, Nb.sub.2 O.sub.5, WO.sub.2, Nb.sub.2 O.sub.3 --TiO.sub.2, Ta.sub.2 O.sub.5 --TiO.sub.2, and V.sub.2 O.sub.5 --ZnO.sub.2. ### Claim 31 (depends on 30) The electrophotographic method as in claim 30, wherein the inorganic fine particles are prepared by a hydrothermal method selected from the group consisting of a hydrothermal oxidation method, a hydrothermal precipitation method, a hydrothermal composition method, a hydrothermal dispersion method, a hydrothermal crystallization method, a hydrothermal hydrolysis method, a hydrothermal agitate-mixing method, and a hydrothermal mechano-chemical method. ### Claim 32 (depends on 30) The electrophotographic method as in claim 30, wherein the inorganic fine particles are titanate fine particles prepared by a hydrothermal method or zirconate fine particles prepared by a hydrothermal method. ### Claim 33 (depends on 30) The electrophotographic method as in claim 30, wherein the inorganic fine particles are titanate fine particles prepared by an oxalate thermal decomposition method or zirconate fine particles prepared by an oxalate thermal decomposition method. ### Claim 34 (depends on 30) The electrophotographic method as in claim 30, wherein the inorganic fine particles are present in an amount of 0.1-5.0 weight parts relative to 100 weight parts of the toner base particles. ### Claim 35 (depends on 30) The electrophotographic method as in claim 30, wherein the negatively charged hydrophobic silica fine particles are present in an amount of 0.1-5.0 weight parts relative to 100 weight parts of the toner base particles. ### Claim 36 (depends on 30) The electrophotographic method as in claim 30, wherein the inorganic fine particles have oppositely chargeable properties with respect to the toner base particles, and have from +3 .mu.C/g to +30 .mu.C/g charge amount with respect to said toner base particles. ### Claim 37 (depends on 30) The electrophotographic method as in claim 30, wherein the conductive elastic roller used in the transferring step comprises a urethane foaming material, to which a conductive additive is added, as an elastic member. ### Claim 38 (depends on 37) The electrophotographic method as in claim 37, wherein the conductive additive is lithium salt. ### Claim 39 (depends on 30) The electrophotographic method as in claim 30, wherein the cleaning is carried out with an elastic urethane blade. ### Claim 40 (depends on 30) The electrophotographic method as in claim 30, wherein the cleaning is carried out with a bias-applied fur brush. ### Claim 41 (depends on 30) The electrophotographic method as in claim 30, wherein the cleaning is carried out with a bias-applied conductive metallic roller. ### Claim 42 (depends on 30) The electrophotographic method as in claim 30, wherein the toner further comprises at least one magnetic component. ### Claim 43 (depends on 30) The electrophotographic method as in claim 30, wherein the toner further comprises at least one pigment. ### Claim 44 An electrophotographic method which comprises: developing an electrostatic latent image formed on a photoconductor using toner, the toner comprising toner base particles comprising a binder resin, and an additive comprising inorganic fine particles of 0.05-4 .mu.m volume-average particle diameter and 0.1-40 m.sup.2 /g specific surface area and negatively charged hydrophobic silica fine particles having 50-350 m.sup.2 /g specific surface area and surface treated with a silicone oil; first transferring the toner to an endless intermediate transfer member which is in contact with the photoconductor; forming a superimposed image of transferred toner by performing the first transfer step more than once; and secondly transferring the superimposed image of transferred toner which is formed on the intermediate transfer member to acceptor paper carried from a feed paper side, wherein the inorganic fine particles are prepared by a hydrothermal method or an oxalate thermal decomposition method and comprise at least one compound selected from the group consisting of CaSiO.sub.3, LaCrO.sub.3, AlPO.sub.4, NbP .sub.3 O.sub.4, LaFeO.sub.3, LiNbO.sub.3, SrTiO.sub.3, BaTiO.sub.3, MgTiO.sub.3, AlTiO.sub.3, CaTiO.sub.3, PbTiO.sub.3, FeTiO.sub.3, SrZrO.sub.3, BaZrO.sub.3, MgZrO.sub.3, AlZrO.sub.3, CaZrO.sub.3, PbZrO.sub.3, MnSiO.sub.3, MgSiO.sub.3, CaSiO.sub.3, MoO.sub.2, SnO.sub.2, ZnO.sub.2, MgO.sub.2, NiO, V.sub.2 O.sub.5, Nb.sub.2 O.sub.5, WO.sub.2, Nb.sub.2 O.sub.3 --TiO.sub.2, Ta.sub.2 O.sub.5 --TiO.sub.2, and V.sub.2 O.sub.5 --ZnO.sub.2. ### Claim 45 (depends on 44) The electrophotographic method as in claim 44, wherein the inorganic fine particles are prepared by a hydrothermal method selected from the group consisting of a hydrothermal oxidation method, a hydrothermal precipitation method, a hydrothermal composition method, a hydrothermal dispersion method, a hydrothermal crystallization method, a hydrothermal hydrolysis method, a hydrothermal agitate-mixing method, and a hydrothermal mechano-chemical method. ### Claim 46 (depends on 44) The electrophotographic method as in claim 44, wherein the inorganic fine particles are titanate fine particles prepared by a hydrothermal method or zirconate fine particles prepared by a hydrothermal method. ### Claim 47 (depends on 44) The electrophotographic method as in claim 44, wherein the inorganic fine particles are titanate fine particles prepared by an oxalate thermal decomposition method or zirconate fine particles prepared by an oxalate thermal decomposition method. ### Claim 48 (depends on 44) The electrophotographic method as in claim 44, wherein the inorganic fine particles are present in an amount of 0.1-5.0 weight parts relative to 100 weight parts of the toner base particles. ### Claim 49 (depends on 44) The electrophotographic method as in claim 44, wherein the negatively charged hydrophobic silica fine particles are present in an amount of 0.1-5.0 weight parts relative to 100 weight parts of the toner base particles. ### Claim 50 (depends on 44) The electrophotographic method as in claim 44, wherein the inorganic fine particles have oppositely chargeable properties with respect to the toner base particles, and have from +3 .mu.C/g to +30 .mu.C/g charge amount with respect to said toner base particles. ### Claim 51 (depends on 44) The electrophotographic method as in claim 44, wherein the toner further comprises at least one magnetic component. ### Claim 52 (depends on 44) The electrophotographic method as in claim 44, wherein the toner further comprises at least one pigment.