Abstract: In the image forming apparatus, a controller applies a collection voltage to a cleaning roller by a voltage application part in image formation process. The controller adjusts the collection voltage applied to the cleaning roller on bases of uncollected toner quantity of a toner image and residual charge of an image carrier, the uncollected toner being part of after-transfer remaining toner which results after formation of the toner image on an outer circumferential surface of the image carrier and transfer of the toner image onto a transfer-objective member, and which has missed being collected by the cleaning roller so as to remain even after one-round rotation of the image carrier.

Abstract: In the image forming apparatus, a controller applies a collection voltage to a cleaning roller by a voltage application part in image formation process. The controller adjusts the collection voltage applied to the cleaning roller on bases of uncollected toner quantity of a toner image and residual charge of an image carrier, the uncollected toner being part of after-transfer remaining toner which results after formation of the toner image on an outer circumferential surface of the image carrier and transfer of the toner image onto a transfer-objective member, and which has missed being collected by the cleaning roller so as to remain even after one-round rotation of the image carrier.

Abstract: In the image forming apparatus, a controller makes a reference image formed on an outer circumferential surface of an image carrier and transferred to a belt. Then, uncollected toner of the reference image, which is part of after-transfer remaining toner of the reference image that has missed being collected so as to remain even after one-round rotation of the image carrier, is transferred to the belt. The controller measures a collectable toner quantity corresponding to an applied voltage of the cleaning roller on a basis of an uncollected toner quantity estimated based on a toner concentration of the uncollected toner, and executes such adjustment that the collectable toner quantity becomes equal to or larger than a maximum value of the after-transfer remaining toner quantity and moreover the applied voltage becomes equal to or lower than a maximum applicable voltage.

Abstract: In the image forming apparatus, a controller applies a collection voltage to a cleaning roller by a voltage application part in image formation process. After making a toner image formed on an outer circumferential surface of an image carrier and transferred to a transfer-objective member, the controller predicts a toner charging level of after-transfer remaining toner which results after the transfer of the toner image, and changes at least either one of absolute value or polarity of the collection voltage applied to the cleaning roller in response to the toner charging level.

Abstract: An image forming apparatus includes an image bearing member and a charging roller that charges a circumferential surface of the image bearing member to a positive polarity. The image bearing member includes a conductive substrate and a photosensitive layer of a single layer, and satisfies formula (1) shown below. The photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. 0.60 ? V ( Q / S ) × ( d / ? r · ? 0 ) ( 1 ) In formula (1), Q represents a charge amount [C] of the circumferential surface of the image bearing member, S represents a charge area [m2] of the charged circumferential surface of the image bearing member, d represents a film thickness [m] of the photosensitive layer, co represents vacuum permittivity [F/m], and V represents a value calculated in accordance with formula V=V0?Vr.

Abstract: An image forming apparatus includes an image bearing member and a charging roller that charges a circumferential surface of the image bearing member to a positive polarity. The image bearing member includes a conductive substrate and a photosensitive layer of a single layer, and satisfies formula (1) shown below. The photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. 0.60 ? V ( Q / S ) × ( d / ? r · ? 0 ) ( 1 ) In formula (1), Q represents a charge amount [C] of the circumferential surface of the image bearing member, S represents a charge area [m2] of the charged circumferential surface of the image bearing member, d represents a film thickness [m] of the photosensitive layer, co represents vacuum permittivity [F/m], and V represents a value calculated in accordance with formula V=V0?Vr.

Abstract: An image forming apparatus includes an image bearing member and a charging roller that charges a circumferential surface of the image bearing member to a positive polarity. The image bearing member includes a conductive substrate and a photosensitive layer of a single layer, and satisfies formula (1) shown below. The charging roller includes a conductive shaft, a base layer covering a surface of the conductive shaft, and a surface layer covering a surface of the base layer. 0.60 ? V ( Q / S ) × ( d / ? r · ? 0 ) ( 1 ) In formula (1), Q represents a charge amount of the circumferential surface of the image bearing member. S represents a charge area of the circumferential surface of the image bearing member. d represents a film thickness of the photosensitive layer. ?r represents a specific permittivity of a binder resin contained in the photosensitive layer. ?0 represents a vacuum permittivity. V represents a value calculated according to formula (2) V=V0?Vr.

Abstract: An image forming apparatus includes an image bearing member and a charging roller that charges a circumferential surface of the image bearing member to a positive polarity. The image bearing member includes a conductive substrate and a photosensitive layer of a single layer, and satisfies formula (1) shown below. The charging roller includes a conductive shaft, a base layer covering a surface of the conductive shaft, and a surface layer covering a surface of the base layer. 0.60 ? V ( Q ? / ? S ) × ( d ? / ? ? r · ? 0 ) ( 1 ) In formula (1), Q represents a charge amount of the circumferential surface of the image bearing member. S represents a charge area of the circumferential surface of the image bearing member. d represents a film thickness of the photosensitive layer. ?r represents a specific permittivity of a binder resin contained in the photosensitive layer. ?0 represents a vacuum permittivity. V represents a value calculated according to formula (2) V=V0?Vr.