Abstract: A process cartridge using an image forming apparatus, including a rotatable image bearing member having a circumferential surface; a developing unit configured to supply a developing agent to the image bearing member; and a cleaning member that cleans the circumferential surface, wherein the developing agent contains a toner including toner particles and a metal soap, the image bearing member includes a plurality of grooves formed on the circumferential surface to extend in a circumferential direction of the circumferential surface and to be arranged side by side in a rotation axis direction, and the plurality of grooves and portions between the grooves form concave-convex portions on the circumferential surface. The circumferential surface of the image bearing member had surface roughness Rz of 0<Rz?0.70 ?m and average interval Sm between concave-convex portions on the circumferential surface of 0<Sm?70.0 ?m.

Abstract: An image forming apparatus including: an image bearing member; a developing member to supply a developer to the image bearing member; and a cleaning member to clean a peripheral surface of the image bearing member in contact with the peripheral surface, wherein a plurality of grooves extend in a circumferential direction on the peripheral surface, and have a width in a generatrix direction of the peripheral surface within a range of at least 0.5 ?m and not more than 40 ?m, and are formed to be side by side in the generatrix direction; the number of the grooves is at least 20 and not more than 1000 per a width of 1000 ?m in the generatrix direction of the peripheral surface; and an average depth (Rvk) of a valley of a projection under a core section of a roughness curve of the peripheral surface is 0.08 ?m or less.

Abstract: An image forming apparatus includes an image bearing member, a developer bearing member, a driving unit, a latent image forming unit that forms an electrostatic image having light area potential and a dark area potential, and an application unit that applies a developing bias. The driving unit drives the image bearing member and the developer bearing member in a first peripheral speed ratio and a second peripheral speed ratio larger than the first peripheral speed ratio. The image forming apparatus further includes an acquiring unit acquiring information related to a change in an electrostatic capacitance of the image bearing member and a determining unit determining a developing contrast according to the electrostatic capacitance. The determining unit determines the developing contrast based on the acquired information when the driving unit drives the image bearing member and the developer bearing member in the second peripheral speed ratio.

Abstract: A method for controlling a hydroformylation reaction for producing an aldehyde by subjecting an olefin, a feed oxo gas containing hydrogen and carbon monoxide, and a recycled gas withdrawn from a reactor and returned to the reactor, to a hydroformylation reaction in the reactor in the presence of a catalyst, which comprises:setting out a target value for the partial pressure of carbon monoxide in the reaction system to control the hydroformylation reaction;detecting the partial pressure of carbon monoxide corresponding to the target value; andcomparing the detected partial pressure of carbon monoxide with the target value to adjust a flow rate of a discharged gas from the reactor; orcomparing the detected partial pressure of carbon monoxide with the target value to adjust a flow rate of the feed oxo gas.