Abstract: The image forming apparatus comprises a photoconductor, a latent electrostatic image forming unit for forming a latent electrostatic image on the photoconductor, a developing unit for developing the latent electrostatic image using a developer comprising a toner to form a visible image, a transfer unit for transferring the visible image to a recording medium, a cleaning unit for removing the developer remained on the photoconductor surface and a developer amount detection unit for detecting developer amount adhering to the photoconductor surface by a reflecting photosensor, wherein the developer stirring time per copy when one copy is made from an original, is 2 to 6 times the developer stirring time per copy when two or more copies are made from the original, wherein the toner comprises at least a binder resin and a wax, and the dynamic frictional coefficient of the toner is 0.15 to 0.45.

Abstract: A carrier and a dummy toner are stored in a developing unit of a process cartridge in a brand new status. A plurality of process cartridges corresponding to a plurality of color toners is used in common. The color toners are respectively supplied to the developing unit from toner supply units after the process cartridges in the brand new status are installed in installation sections in a main unit of an image forming apparatus.

Abstract: A process cartridge is provided with a frame body made up of at least first and second frame bodies that are movable relative to each other to form a space, a frame body positioning member positioning the first and second frame bodies, a latent image bearing member supported by the frame body and replaceable via the space formed by the first and second frame bodies, a developing unit supplying a developing agent to the latent image bearing member, and a developing position determining member. The developing position determining member is disposed at a non-overlapping position relative to the frame body positioning member, and positions the developing unit with respect to the frame body.

Abstract: An ultra high-strength hydraulic cement composition contains a binder, fine aggregates, coarse aggregates, an antifoaming agent, water and a specified admixture and has a unit amount of the binder in the range of 480-1800kg/m3. Water and the binder are contained at a ratio of 10-25% and the admixture is contained in the amount of 0.2-3.5 weight parts per 100 weight parts of the binder. The binder may be cement or a mixture of cement and a microscopic powder admixture. The admixture is one or more selected from reaction mixtures obtained by specified two processes and partially or completely neutralized substances obtained from such a reaction mixture through these two processes and also a specified third process.

Abstract: A multi-functional admixture for concrete, having improved fluidity for providing hardened materials with improved early strength, smaller shrinkage rate, improved resistance against freezing and thawing action and slower carbonation speed, contains a specified kind of graft copolymer and/or its salt, a specified kind of (poly)alkyleneglycol monoalkyl ether and a specified kind of organic phosphate at specified ratios.

Abstract: A high-strength hydraulic cement composition contains cement, fine aggregates, coarse aggregates, water and a specified admixture and has a unit amount of water in the range of 120-185 kg/m3. Water and the cement are contained at a ratio of 20-40% and the admixture is contained in the amount of 0.1-3.0 weight parts per 100 weight parts of the cement. The admixture is one or more selected from reaction mixtures obtained by specified two processes and partially or completely neutralized substances obtained from such a reaction mixture through these two processes and also a specified third process.

Abstract: Cement dispersants made of graft copolymers of a specified type and/or their salts are produced by using as an intermediate product allyletherester monomers prepared by an esterification reaction of ?-allyl-?-hydroxy-polyoxyalkylene refined so as to have peroxide value less than 5.0 meq/kg and aliphatic monocaboxylic acid under a specified condition in the absence of solvent and in the presence of an antioxidant.

Abstract: A multi-functional admixture for simultaneously providing specified characteristics to hydraulic cement compositions such as concrete contains one or more of specified reaction mixtures obtained by specified two processes as well as partially or completely neutralized substances obtained from such a reaction mixture through a specified third process. The specified two processes include initiating a radical copolymerization process of a radical polymerizable monomer mixture containing maleic anhydride and a monomer of a specified kind in a non-aqueous system in the presence of a non-aqueous radical initiator and stopping the radical copolymerization reaction in its midst while the inversion rate of polymerization is at a specified level by adding water to the reaction system to thereby obtain a reaction mixture. The specified third process is for partially or completely neutralizing the reaction mixture.

Abstract: Allyletherester monomers to be used as an intermediate product for the production of graft copolymers and/or their salts for use as cement dispersants are prepared by an esterification reaction of ?-allyl-?-hydroxy-polyoxyalkylene refined so as to have peroxide value less than 5.0 meq/kg and aliphatic monocaboxylic acid under a specified condition in the absence of solvent and in the presence of an antioxidant.

Abstract: A carrier and a dummy toner are stored in a developing unit of a process cartridge in a brand new status. A plurality of process cartridges corresponding to a plurality of color toners is used in common. The color toners are respectively supplied to the developing unit from toner supply units after the process cartridges in the brand new status are installed in installation sections in a main unit of an image forming apparatus.

Abstract: A gypsum slurry composition contains gypsum, a dispersant and water. A graft copolymer substance of a specified kind, which is one or more of graft copolymers and their salts obtained by specified processes, is contained as the dispersant in an amount of 0.01-1.0 weight %.

Abstract: A stopper member is included in a linear actuator comprising a stator assembly, a rotor assembly, an output shaft, and a stopper pin which is fixedly disposed at a frontward portion of the output shaft, and which is adapted to axially control the mode and amount of movement of the output shaft initiated by rotation of the rotor assembly. The stopper member is disposed fixedly with respect to the stator assembly and stops the axial movement of the output shaft without making it happen that the stopper pin which moves together with the output shaft touches the rotor assembly.

Abstract: The image forming apparatus comprises a photoconductor, a latent electrostatic image forming unit for forming a latent electrostatic image on the photoconductor, a developing unit for developing the latent electrostatic image using a developer comprising a toner to form a visible image, a transfer unit for transferring the visible image to a recording medium, a cleaning unit for removing the developer remained on the photoconductor surface and a developer amount detection unit for detecting developer amount adhering to the photoconductor surface by a reflecting photosensor, wherein the developer stirring time per copy when one copy is made from an original, is 2 to 6 times the developer stirring time per copy when two or more copies are made from the original, wherein the toner comprises at least a binder resin and a wax, and the dynamic frictional coefficient of the toner is 0.15 to 0.45.

Abstract: A gypsum slurry composition contains gypsum, a dispersant and water. A graft copolymer substance of a specified kind, which is one or more of graft copolymers and their salts obtained by specified processes, is contained as the dispersant in an amount of 0.01-1.0 weight %.

Abstract: Allyletherester monomers are prepared by an esterification reaction of &agr;-allyl-&ohgr;-hydroxy-polyoxyalkylene refined so as to have peroxide value less than 5.0 meq/kg and aliphatic monocaboxylic acid under a specified condition in the absence of solvent and in the presence of an antioxidant. Allyletherester monomers thus prepared are used as an intermediate produce for the production of graft copolymers and/or their salts to be used as cement dispersant.

Abstract: A multi-functional cement dispersant contains a graft copolymer obtained by a graft reaction of one or more selected from polyoxyalkylene monoalkylester, polyoxyalkylene monoalkylether and polypropyleneglycol of specified kinds to a copolymer obtained by radical polymerization of a mixture of radical polymerizable monomers containing maleic anhydride and monomers of a specified kind at a specified ratio. Hydraulic cement compositions produced with such a multi-functional cement dispersant have a superior fluidity with reduced loss over time and hardened objects produced from such a composition exhibit a superior early strength and have a low dry shrinkage and a high resistance against freezing and thawing.

Abstract: An agent for stabilizing air content of hydraulic cement compositions includes graft copolymers obtained by a first step in which copolymers with average numerical molecular weight 5000-50000 are obtained by radical polymerization of a mixture of radical polymerizable monomers containing anhydrous maleic acid and monomers of a specified form, together in an amount of 80 molar % or more and at molar ratio of 40/60-60/40 and a second step in which graft copolymers are obtained by a graft reaction of 100 weight parts of the copolymers obtained in the first step and 7-60 weight parts of polyoxyalkylene monoalkylether and/or polyoxyalkylene monoalkenylether with a block addition of a total of 23-70 moles of ethylene oxide and propylene oxide per 1 mole of aliphatic alcohol with 8-20 carbon atoms. A hydraulic cement composition is produced with cement, aggregates, water, a cement dispersant, an agent for controlling air content and contains an agent for stabilizing air content as described above in the amount of 0.

Abstract: Allyletherester monomers are prepared by an esterification reaction of &agr;-allyl-&ohgr;-hydroxy-polyoxyalkylene refined so as to have peroxide value less than 5.0 meq/kg and aliphatic monocaboxylic acid under a specified condition in the absence of solvent and in the presence of an antioxidant. Allyletherester monomers thus prepared are used as an intermediate produce for the production of graft copolymers and/or their salts to be used as cement dispersant.

Abstract: An apparatus including a development agent carrying member, a toner container having an opening, an initial development agent container, a flexible member, and a stopper. The flexible member rotates to cyclically transfer toner to the carrying member via the opening. The stopper locates the flexible member at a closed position where the opening is closed. The flexible member is initially located at the closed position and releases the opening when the development agent is present on a surface of the carrying member facing the opening. A method of image forming is provided that includes sealing the opening by engaging the flexible member with the stopper, filling the toner container, supplying a development agent to the carrying member at a surface of the development agent facing the opening, and releasing the opening to start supplying the toner to the carrying member through the opening by rotation of the flexible member.

Abstract: A multi-functional cement dispersant contains a graft copolymer obtained by a graft reaction of one or more selected from polyoxyalkylene monoalkylester, polyoxyalkylene monoalkylether and polypropyleneglycol of specified kinds to a copolymer obtained by radical polymerization of a mixture of radical polymerizable monomers containing maleic anhydride and monomers of a specified kind at a specified ratio. Hydraulic cement compositions produced with such a multi-functional cement dispersant have a superior fluidity with reduced loss over time and hardened objects produced from such a composition exhibit a superior early strength and have a low dry shrinkage and a high resistance against freezing and thawing.