摘要:
A two-component type developer for developing an electrostatic image is constituted by at least a toner and a magnetic carrier. The toner has a weight-average particle size D4 of at most 10 .mu.m and a number-average particle size D1 satisfying D4/D1.ltoreq.1.5. The magnetic carrier comprises composite particles comprising magnetic iron compound particles, non-magnetic metal oxide particles, and a binder comprising a phenolic resin. The composite particles contain the magnetic iron compound and the non-magnetic metal oxide in a total proportion of 80-99 wt. %. The magnetic iron compound particles have a number-average particle size ra, and the non-magnetic metal oxide particles have a number-average particle size r.sub.b satisfying r.sub.b /r.sub.a >1.0.
摘要:
A two-component type developer for developing an electrostatic image is constituted by at least a toner and a magnetic carrier. The toner has a weight-average particle size D4 of 1-10 .mu.m, a number-average particle size D1 and such a particle size distribution that particles having size of at most D1/2 occupy at most 20% by number and particles having sizes of at least D4.times.2 occupy at most 10% by volume. The magnetic carrier has a number-average particle size of 1-100 .mu.m and contains at most 20% by number of particles having sizes in the range of at most a half of the number-average particle size, the magnetic carrier has a resistivity of at least 1.times.10.sup.12 ohm.cm and has a core having a resistivity of at least 1.times.10.sup.10 ohm.cm, and the magnetic carrier has a magnetization at 1 kilo-oersted of 30-150 emu/g.
摘要:
A magnetic coated carrier suitable for constituting a two-component type developer for use in electrophotography is composed of magnetic coated carrier particles comprising magnetic coated carrier particles comprising magnetic carrier core particles each comprising a binder resin and metal oxide particles, and a coating layer surface-coating each carrier core particle. The metal oxide particles have been subjected to a surface lipophilicity-imparting treatment. The magnetic carrier core particles have a resistivity of at least 1.times.10.sup.10 ohm.cm, and the magnetic coated carrier has a resistivity of at least 1.times.10.sup.12 ohm.cm. The magnetic coated carrier has a particle size distribution such that (i) it has a number-average particle size Dn of 5-100 .mu.m, (ii) it satisfies a relationship of Dn/.sigma..gtoreq.3.5, wherein .sigma. denotes a standard deviation of number-basis particle size distribution of the carrier, and (iii) it contains at most 25% by number of particles having particle sizes of at most Dn.times.2/3.
摘要:
A toner is comprised of toner particles composed of at least a binder resin and a clorant, wherein the toner particles each have a coating layer formed on their surfaces in a state of particulate matters being stuck to one another. The particulate matters contains at least a silicon compound.
摘要:
A developing method including the steps of: stirring a two component-type developer which contains a toner and a carrier; conveying the developer to a developing section with a conveying screw and a developer carrying member; and developing an electrostatic latent image on an image holding member by forming a magnetic brush on a developing magnetic pole, wherein the carrier is a magnetic material dispersion-type resin carrier containing a binder resin and a metal oxide, has a low coercive force and has been previously exposed and magnetized in a specific magnetic field and has stable residual magnetization, thereby imparting a high durability to the developer and making it usable for a long time to reproduce a large number of images having stable qualities.
摘要:
A two-component type developer for developing an electrostatic image is constituted by at least a toner and a magnetic carrier. The toner has a weight-average particle size D4 of at most 10 .mu.m and a number-average particle size D1 satisfying D4/D1.ltoreq.1.5. The magnetic carrier comprises composite particles comprising magnetic iron compound particles, non-magnetic metal oxide particles, and a binder comprising a phenolic resin. The composite particles contain the magnetic iron compound and the non-magnetic metal oxide in a total proportion of 80-99 wt. %. The magnetic iron compound particles have a number-average particle size ra, and the non-magnetic metal oxide particles have a number-average particle size r.sub.b satisfying r.sub.b /r.sub.a >1.0.
摘要:
A carrier for use in electrophotography has carrier particles. The carrier particles each comprise a carrier core particle and a resin for coating the carrier core particle and having a resistivity of 10.sup.10 .OMEGA..multidot.cm or above under conditions of a temperature of 23.degree. C. and a humidity of 50% RH. The carrier particles have an average particle diameter of not larger than 100 .mu.m and a resistivity of 10.sup.10 .OMEGA..multidot.cm or above. The carrier particles comprise not less than 80% by number of resin-coated carrier particles whose carrier core particles are each coated with a resin in a coverage of not less than 90%.
摘要:
A toner is comprised of toner particles composed of at least a binder resin and a clorant, wherein the toner particles each have a coating layer formed on their surfaces in a state of particulate matters being stuck to one another. The particulate matters contains at least a silicon compound.
摘要:
A process for producing toner particles is conducted by:preparing toner precursor particles containing at least binder resin and coloring agent; andspherizing the toner precursor particles to obtain toner particles;wherein spherizing steps include;(1) dispersing the toner precursor particles in an aqueous medium containing a dispersant, thereby preparing a disperse system (a);(2) dispersing oil droplet particles containing a softening agent into an aqueous medium, thereby preparing a disperse system (b);(3) preparing a mixed disperse system (c) by adding the disperse system (a) to the disperse system (b), and causing the softening agent to be absorbed by the toner precursor particles in the mixed disperse system (c); and(4) removing the softening agent from the toner precursor particles.
摘要:
A magnetic coated carrier suitable for constituting a two-component type developer for use in electrophotography is composed of magnetic coated carrier particles comprising magnetic carrier core particles and a resinous surface coated layer coating the magnetic carrier core particles. The carrier is suitably constituted so as to satisfy the condition of: (a) the magnetic carrier core particles has a resistivity of at least 1.times.10.sup.10 ohm.cm, and the magnetic coated carrier has a resistivity of at least 1.times.10.sup.12 ohm.cm, (b) the magnetic coated carrier has a number-average particle size of 1-100 .mu.m and has such a particle size distribution that particles having particle sizes of at most a half of the number-average particle size occupy an accumulative percentage of at most 20% by number, (c) the magnetic coated carrier has a shape factor SF-1 of 100-130, (d) the magnetic coated carrier has a magnetization at 1 kilo-oersted of 40-250 emu/cm.sup.3, and (e) the resinous surface coating layer comprises a coating resin composition which in turn comprises a straight silicone resin and a coupling agent. The straight silicone resin includes trifunctional silicon and difunctional silicon in an atomic ratio of 100:0-40:60.