IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD

• Main Authors: NISHIMURA KEIYA, IMANAKA YOSHITAKA, ISHINO MASATO, FUJITA TOSHIKI
• Format: Patent
• Language: English; Japanese
• Published: 18.02.2021
• Subjects: BEARINGS; BLASTING; CINEMATOGRAPHY; ELECTROGRAPHY; ELECTROPHOTOGRAPHY; ELEMENTS OR CRANKSHAFT MECHANISMS; ENGINEERING ELEMENTS AND UNITS; FLEXIBLE SHAFTS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; HEATING; HOLOGRAPHY; LIGHTING; MAGNETOGRAPHY; MECHANICAL ENGINEERING; PHOTOGRAPHY; PHYSICS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; SHAFTS; THERMAL INSULATION IN GENERAL; WEAPONS

To provide, in the present invention, an image forming apparatus that can prevent the occurrence of a ghost image and uneven charging.SOLUTION: An image forming apparatus of the present invention comprises: an image carrier; and a charging roller that charges a peripheral surface of the image carrier to a positive polarity. The image carrier includes a conductive substrate and a single-layer photosensitive layer and satisfies the formula (1). The photosensitive layer contains a charge generating agent, a hole transport agent, an electron transport agent, and a first binder resin. The charging roller includes a conductive shaft, a base layer that covers a surface of the conductive shaft, and a surface layer. The volume resistivity of the surface layer is 13.0 logΩ cm or more at a temperature of 32.5 degrees and a humidity of 80%RH. (Q represents the amount of electrified charge of the image carrier, S the area of charging of the image carrier, d the thickness of the photosensitive layer, εr the dielectric constant of the first binder resin contained in the photosensitive layer, ε0 the dielectric constant of vacuum, and V a value calculated from V=V0-Vr.)SELECTED DRAWING: Figure 12 【課題】本発明は、ゴースト画像及び帯電ムラの発生を抑制できる画像形成装置を提供する。【解決手段】本発明の画像形成装置は、像担持体と、像担持体の周面を正極性に帯電させる帯電ローラーとを備える。像担持体は、導電性基体と、単層の感光層とを備え、かつ式（１）を満たす。感光層は、電荷発生剤と、正孔輸送剤と、電子輸送剤と、第１バインダー樹脂とを含有する。帯電ローラーは、導電性シャフトと、導電性シャフトの表面を被覆する基層と、表層とを備える。表層の体積抵抗率は、温度３２．５度、湿度８０％ＲＨにおいて、１３．０ｌｏｇΩ・ｃｍ以上である。（Ｑは像担持体の帯電電荷量を、Ｓは像担持体の帯電面積を、ｄは感光層の膜厚を、εrは感光層に含有される第１バインダー樹脂の比誘電率を、ε0は真空の誘電率を、Ｖは式Ｖ＝Ｖ0−Ｖrから算出される値を表す。）【選択図】図１２