CARRIER FOR ELECTROSTATIC CHARGE IMAGE DEVELOPMENT, DEVELOPER FOR ELECTROSTATIC CHARGE IMAGE DEVELOPMENT, DEVELOPER CARTRIDGE, PROCESS CARTRIDGE, AND IMAGE FORMING APPARATUS

• Main Authors: HASEGAWA TOSHIAKI, KAKEHI SOTARO, IIZUKA AKIHIRO, YASUNO SHINTARO
• Format: Patent
• Language: English; Japanese
• Published: 18.01.2016
• Subjects: CINEMATOGRAPHY; ELECTROGRAPHY; ELECTROPHOTOGRAPHY; HOLOGRAPHY; MAGNETOGRAPHY; PHOTOGRAPHY; PHYSICS

PROBLEM TO BE SOLVED: To provide a carrier for electrostatic charge image development, configured to prevent an image defect due to reduction in carrier resistance, while ensuring a high-quality image stably, even after long-term image formation in a high-temperature/high-humidity environment, developer for electrostatic charge image development, a developer cartridge, a process cartridge, and an image forming apparatus.SOLUTION: A carrier for electrostatic charge image development contains: a magnetic core material particle including calcium of at least 0.05 to 1.0 mass%, and having a ratio b/a of 5 between an internal calcium content ratio (a) and a calcium content ratio (b) of a surface section; and a resin coating layer covering a surface of the magnetic core material particle. A ratio c/b between the calcium content ratio (b) and a calcium content ratio (c) of the surface section covered with the resin coating layer is 0.1 to 0.5. 【課題】高温高湿下での長期の画像形成後においても、安定して高画像を確保しつつ、キャリア抵抗の低下に起因する画像欠陥が抑制される静電荷像現像用キャリア、静電荷像現像用現像剤、現像剤カートリッジ、プロセスカートリッジおよび画像形成装置を提供する。【解決手段】少なくとも、０．０５質量％以上１．０質量％以下のカルシウムを含み、内部のカルシウム含有比率（ａ）に対する表面部のカルシウム含有比率（ｂ）の比ｂ／ａが５以上である磁性芯材粒子と、前記磁性芯材粒子の表面を被覆している樹脂被覆層とを含有し、前記カルシウム含有比率（ｂ）に対する、樹脂被覆層で被覆された後の表面部のカルシウム含有比率（ｃ）の比ｃ／ｂが０．１以上０．５以下である静電荷像現像用キャリア。【選択図】図１