The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 23, 2026
Filed:
Aug. 22, 2023
Fujifilm Business Innovation Corp., Tokyo, JP;
FUJIFILM Business Innovation Corp., Tokyo, JP;
Abstract
An electrostatic charge image developer contains a toner including toner particles that contain a binder resin and a carrier including magnetic particles and a resin layer that adheres to a surface of the magnetic particles, in which, in a dynamic viscoelasticity measurement of the toner, in a case where a loss tangent tanδ at a temperature of 90° C. and a strain of 1% is represented by D1 (90), a loss tangent tanδ at a temperature of 90° C. and a strain of 50% is represented by D50 (90), a loss tangent tanδ at a temperature of 150° C. and a strain of 1% is represented by D1 (150), and a loss tangent tanδ at a temperature of 150° C. and a strain of 50% is represented by D50 (150), each of D1 (90), D50 (90), D1 (150), and D50 (150) is 0.5 or more and 2.5 or less, a value of D50 (150)−D1 (150) is less than 1.5, and a value of D50 (90)−D1 (90) is less than 1.0, and in the surface of the magnetic particles, an average unevenness interval Sm and an arithmetic mean roughness Ra satisfy 0.5 μm≤ Sm≤2.5 μm and 0.3 μm≤ Ra≤1.2 μm.