公开(公告)号：US5212524A

公开(公告)日：1993-05-18

申请号：US937114

申请日：1992-08-31

申请人： Hirohide Tanikawa ,  Yasutaka Akashi ,  Masaki Uchiyama ,  Makoto Unno ,  Masaaki Taya

发明人： Hirohide Tanikawa ,  Yasutaka Akashi ,  Masaki Uchiyama ,  Makoto Unno ,  Masaaki Taya

IPC分类号： G03G9/08 ,  G03G9/083 ,  G03G9/087

CPC分类号： G03G9/0819 ,  G03G9/0835 ,  G03G9/0838 ,  G03G9/08733

摘要： A toner for developing electrostatic images, comprises a binder resin and a colorant, wherein the binder resin comprises a vinyl copolymer having an acid anhydride group, and the binder resin has a total acid value (A) of 2-100 mgKOH/g and a total acid value (B) attributable to acid anhydride group of below 6 mgKOH/g so that [(B)/(A)].times.100 is 60% or less. Because the binder resin has a specified acid value partly attributable to acid anhydride group, the toner is provided with an adequate balance between chargeability and dischargeability, so that the toner shows a stable performance under various environmental conditions. The toner is particularly advantageously constituted as a magnetic toner of fine particle sizes suitably used under application of unsymmetrical alternating bias electric field.

摘要翻译： 用于显影静电图像的调色剂包括粘合剂树脂和着色剂，其中粘合剂树脂包括具有酸酐基的乙烯基共聚物，并且粘合剂树脂的总酸值（A）为2-100mgKOH / g，和 归因于酸酐基团的总酸值（B）低于6mgKOH / g，使得[（B）/（A）]×100为60％以下。 由于粘合剂树脂具有部分归因于酸酐基团的特定酸值，因此调色剂在带电性和放电性之间具有足够的平衡，使得调色剂在各种环境条件下显示出稳定的性能。 调色剂特别有利地构成为适用于不对称交流偏压电场的细粒度的磁性调色剂。

公开(公告)号：US5175070A

公开(公告)日：1992-12-29

申请号：US588436

申请日：1990-09-26

申请人： Hirohide Tanikawa ,  Yasutaka Akashi ,  Masaaki Taya ,  Kuniko Kobayashi ,  Masaki Uchiyama

发明人： Hirohide Tanikawa ,  Yasutaka Akashi ,  Masaaki Taya ,  Kuniko Kobayashi ,  Masaki Uchiyama

IPC分类号： G03G9/08 ,  G03G13/09 ,  G03G15/09

CPC分类号： G03G13/09 ,  G03G15/0907 ,  G03G9/0819

摘要： An image forming apparatus is formed by providing a latent image-bearing member for holding an electrostatic image thereon and a toner-carrying member for carrying a prescribed magnetic toner comprising a binder resin and magnetic powder and having a particle size distribution including 12% by number or more of magnetic toner particles of 5 microns or smaller, 33% by number or less of magnetic toner particles of 8-12.7 microns and 2% by volume or less of magnetic toner parcitles of 16 microns or larger so as to provide a volume-average particle size of 4-10 microns. At the developing station, an alternating bias voltage comprising a DC voltage and an unsymmetrical AC voltage in superposition is applied between the toner-carrying member and the latent image-bearing member to provide an alternating bias electric field comprising a development-side voltage component and a reverse-development side voltage component. The development-side voltage component has a magnitude equal to or larger than that of the reverse development-side voltage component and a duration smaller than that of the reverse-development side voltage component, so that the magnetic toner on the toner-carrying member, particularly fine powdery fraction thereof effective for high-quality development, is effectively transferred to the latent image-bearing member to develop the electrostatic image thereon at the developing station.

公开(公告)号：US5169738A

公开(公告)日：1992-12-08

申请号：US604207

申请日：1990-10-29

申请人： Hirohide Tanikawa ,  Yasutaka Akashi ,  Masaki Uchiyama ,  Makoto Unno ,  Masaaki Taya

发明人： Hirohide Tanikawa ,  Yasutaka Akashi ,  Masaki Uchiyama ,  Makoto Unno ,  Masaaki Taya

IPC分类号： G03G9/08 ,  G03G9/083 ,  G03G9/087

CPC分类号： G03G9/0819 ,  G03G9/0835 ,  G03G9/0838 ,  G03G9/08733

摘要： A toner for developing electrostatic images, comprises a binder resin and a colorant, wherein the binder resin comprises a vinyl copolymer having an acid anhydride group, and the binder resin has a total acid value (A) of 2-100 mgKOH/g and a total acid value (B) attributable to acid anhydride group of below 6 mgKOH/g so that [(B)/(A)].times.100 is 60% or less. Because the binder resin has a specified acid value partly attributable to acid anhydride group, the toner is provided with an adequate balance between chargeability and dischargeability, so that the toner shows a stable performance under various environmental conditions. The toner is particularly advantageously constituted as a magnetic toner of fine particle sizes suitably used under application of unsymmetrical alternating bias electric field.

公开(公告)号：US4978597A

公开(公告)日：1990-12-18

申请号：US316802

申请日：1989-02-28

申请人： Toshiaki Nakahara ,  Hirohide Tanikawa

发明人： Toshiaki Nakahara ,  Hirohide Tanikawa

IPC分类号： G03G13/08 ,  G03G9/08 ,  G03G9/083 ,  G03G13/09 ,  G03G15/08 ,  G03G15/09

CPC分类号： G03G13/09 ,  G03G15/0928 ,  G03G9/0819

摘要： An image forming apparatus, comprises an electrostatic image-bearing member for holding an electrostatic charge image and a toner-carrying member having a surface for carrying a magnetic toner thereon, wherein the surface of the toner-carrying member has an unevenness comprising sphere-traced concavities formed by blasting with particles with a definite spherical shape; the magnetic toner comprisaes 17-60% by number of particles of 5 microns or smaller, 1-23% by number of particles of 8-12.7 microns, and 2.0% by volume or less of particles of 16 microns or larger and has a volume-average particle size of 4-11 microns; the electrostatic image-bearing member and the toner-carrying member are disposed with a prescribed gap therebetween at a developing station; means for forming a magnetic toner layer on the toner-carrying member in a thickness which is thinner than the prescribed gap; and means for applying an alternating electric field for development with the magnetic toner at the developing station. The surface of the toner-carrying member comprising the sphere-traced concavities allows the forming of a uniform thin toner layer thereon when combined with the magnetic toner having a specific particle size distribution while the soiling of the surface is prevented for a long period of use.