Toner and two-component developer
First Claim
Patent Images
1. A toner, comprising:
- toner particles each containing a binder resin, a wax, and a coloring agent; and
silica fine particles A and strontium titanate fine particles B present on surfaces of the toner particles,wherein;
the silica fine particles A have a number-average particle diameter (D1) of 60 nm or more and 300 nm or less;
whena coverage rate of the surfaces of the toner particles with the silica fine particles A is defined as a coverage rate X (%) anda coverage rate with the silica fine particles A fixed to the surfaces of the toner particles is defined as a coverage rate Y (%),the coverage rate X is 20% or more and 95% or less, anda ratio [coverage rate Y/coverage rate X] of the coverage rate Y to the coverage rate X is 0.75 or more;
the strontium titanate fine particles B have a fixing rate, measured as indicated in the description, of 0.10 or more and 0.60 or less;
the silica fine particles A are negatively chargeable;
the strontium titanate fine particles B are positively chargeable;
an amount of the silica fine particles A is 2.0 parts by mass or more and 10.0 parts by mass or less when an amount of the toner particles is set to 100 parts by mass; and
an amount of the strontium titanate fine particles B is 0.2 part by mass or more and 1.0 part by mass or less when an amount of the toner particles is set to 100 parts by mass.
1 Assignment
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Accused Products
Abstract
Provided are a toner and a two-component developer each of which: shows a small fluctuation in charge quantity and a small fluctuation in image density even under a high-temperature and high-humidity environment; and does not cause any member contamination even after endurance and hence can stably output an image. The toner and the two-component developer each have a feature in that positively chargeable strontium titanate fine particles are added to toner particles having fixed thereto negatively chargeable silica fine particles.
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Citations
5 Claims
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1. A toner, comprising:
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toner particles each containing a binder resin, a wax, and a coloring agent; and silica fine particles A and strontium titanate fine particles B present on surfaces of the toner particles, wherein; the silica fine particles A have a number-average particle diameter (D1) of 60 nm or more and 300 nm or less; when a coverage rate of the surfaces of the toner particles with the silica fine particles A is defined as a coverage rate X (%) and a coverage rate with the silica fine particles A fixed to the surfaces of the toner particles is defined as a coverage rate Y (%), the coverage rate X is 20% or more and 95% or less, and a ratio [coverage rate Y/coverage rate X] of the coverage rate Y to the coverage rate X is 0.75 or more; the strontium titanate fine particles B have a fixing rate, measured as indicated in the description, of 0.10 or more and 0.60 or less; the silica fine particles A are negatively chargeable; the strontium titanate fine particles B are positively chargeable; an amount of the silica fine particles A is 2.0 parts by mass or more and 10.0 parts by mass or less when an amount of the toner particles is set to 100 parts by mass; and an amount of the strontium titanate fine particles B is 0.2 part by mass or more and 1.0 part by mass or less when an amount of the toner particles is set to 100 parts by mass. - View Dependent Claims (2, 3, 4, 5)
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Specification