An image forming apparatus comprises: an image processor to convert image data based on a conversion condition; an image forming unit to form an image based on the converted image data using a replaceable member; a memory to store the image data and the converted image data; a sensor to perform measurement on a test image; and a controller. If the replacement of the replaceable member is detected while forming images, the controller controls the image forming unit to form the test image and generates the conversion condition based on a result of the measurement on the test image. If the replacement of the replaceable member is detected while forming the images, the controller further controls the image processor to convert the image data stored in the memory based on the generated conversion condition.

A photosensitive member unit includes a photosensitive member, a charging roller, a charging roller bearing member, a gear, a separation member having an engagement portion, a guide portion, and a frame to support the photosensitive member. The guide portion guides the charging roller bearing member urged by a urging member to separate the charging roller from the photosensitive member in a state where the engagement portion and the gear are engaged with each other and guides the charging roller bearing member urged by the urging member so that the charging roller comes into contact with the photosensitive member in a state where the engagement portion and the gear are not engaged. A distance between the urged charging roller bearing member and the frame is less than a length in which the engagement portion and the gear are engaged in the state where the engagement portion and the gear are engaged.

In one example, a device includes a flexible roller and an actuator to flex the roller while it is rotating to change the gap between the roller and a surface opposite the roller.

A charging member includes a support, a conductive elastic layer disposed on the support, and a surface layer disposed on the conductive elastic layer. Domains with current values of 2.5 pA or more have an average size of about 300 nm or less in a binary image created using a current value of 2.5 pA as a threshold from current measured by contacting a conical probe having a tip diameter of 20 nm with an outer surface of the surface layer and applying a voltage of 3 V between the conical probe and the support while moving the conical probe.

An image-forming apparatus includes a rotatable developer-bearing member to bear a developer composed of a toner particle and a transfer promoting particle attached to the toner particle. When F denotes pressing force for pressing the developer-bearing member against an image-bearing member, and N denotes a total number of the transfer promoting particles interposed between the toner particle and the image-bearing member, adhesion strength Ft between the transfer promoting particle and the toner particle measured by pressing the transfer promoting particle against the toner particle at a pressing force per unit transfer promoting particle F/N and adhesion strength Fdr between the transfer promoting particle and the image-bearing member measured by pressing the transfer promoting particle against the image-bearing member at the pressing force per unit transfer promoting particle F/N, satisfy Ft<Fdr. Electrical discharge is generated upstream of a transfer portion in a movement direction of an intermediate transfer belt.

An electrophotographic roller includes: a mandrel and an elastic layer on the mandrel, and having a crown shape in which a diameter decreases from a central position O in a longitudinal direction of the mandrel toward an end portion. When a position of the end portion in the longitudinal direction of the elastic layer is defined as X2, a position between the O and the X2 is defined as Xl, a distance between the O and the X1 is defined as L1, and a distance between the X1 and the X2 is defined as L2, L1=0.6×(L1+L2). When outer diameters of the electrophotographic roller at O, X1 and X2 are defined as Do, DX1 and DX2, respectively, and Z1=(Do−DX1)/2 and Z2=(DX1−DX2)/2 are defined, Z1, Z2, L1 and L2 satisfy (Z2/L2)<1.931×(Z1/L1).

An electrophotographic roller includes: a mandrel and an elastic layer on the mandrel, and having a crown shape in which a diameter decreases from a central position O in a longitudinal direction of the mandrel toward an end portion. When a position of the end portion in the longitudinal direction of the elastic layer is defined as X2, a position between the ) and the X2 is defined as X1, a distance between the O and the X1 is defined as L1, and a distance between the X1 and the X2 is defined as L2, L1=0.6×(L1+L2). When outer diameters of the electrophotographic roller at O, X1 and X2 are defined as Do, DX1 and DX2, respectively, and Z1=(Do−DX1)/2 and Z2=(DX1−DX2)/2 are defined, Z1, Z2, L1 and L2 satisfy (Z2/L2)<1.931×(Z1/L1).

Disclosed are an apparatus and method for forming a fine pattern. The apparatus for forming the fine pattern includes a lower electrode disposed on a bottom face of a fluid thin-film; an upper electrode positioned above the lower electrode, and spaced apart from the lower electrode by a first spacing, wherein a master pattern is formed on a bottom face of the upper electrode; and a power device configured to apply a high-voltage to between the lower electrode and the upper electrode, thereby generating an electric field therebetween.

An image forming method includes forming, fixing, and applying. The forming forms a toner image on a recording medium by an image forming device. The fixing fixes the toner image on the recording medium with heat by a fixing device. The applying applies an electric charge by a charge applying device to the recording medium on which the toner image has been fixed by the fixing device, in a state in which an output-adjustable power source for the charge applying device has an electric current that is controlled to be constant.

An image forming apparatus includes a charging unit that charges an image bearing member, a developing unit that forms a toner image on an latent image formed on the image bearing member, a transfer unit that transfers the toner image onto a transfer material, a charge neutralizer that neutralizes a charge of the image bearing member downstream of a transfer portion and upstream of a charging portion in a rotating direction of the image bearing member, a conductive collecting unit that collects a material adhering on the image bearing member downstream of the transfer portion and upstream of the charging portion, wherein the developing unit collects residual toner on the image bearing member, an voltage application unit sets a potential difference between the voltage applied to the collecting unit and the surface electric potential of the image bearing member not more than a discharge threshold.