Ricoh Company, Ltd.

Tatsuya Ohsugi

Junpei Fujita

Kazuki Yogosawa

Yuuji Wada

Kenji Sugiura

Naohiro Kumagai

Seiichi Kogure

Takehide Mizutani

Hiroyoshi Haga

Hirokazu Ishii

Naoto Kochi

Shinya Tanaka

Toshitaka Yamaguchi

Mitsuru Takahashi

Kenji Sengoku

Masayoshi Nakayama

Jyunya Sakuraba

Ryo Hasegawa

Masaharu Furuya

Osamu Ichihashi

Tsutomu Kato

Masakazu Imai

Katsuhito Haruno

Kenji Sugirua

A toner conveyance device includes a conveyance path including a flowing-in portion to receive toner and a discharge portion to discharge the toner, a conveying screw to convey the toner from the flowing-in portion to the discharge portion, and a toner loosener disposed in at least one of the flowing-in portion and the discharge portion. The toner loosener includes at least one loosening portion to be vibrated by contact with the conveying screw and a support to cantilever the loosening portion. The loosening portion includes a first contact portion and a second contact portion disposed farther than the first contact portion from the support. A distance from the support to the second contact portion is longer than a distance from the support to the first contact portion in a longitudinal direction of the conveying screw.

Toner conveyance device including a toner loosener and image forming apparatus including the toner conveyance device

An image forming apparatus includes a belt-shaped image bearer, a transferer, a guide, two rotators, and a support. The image bearer has an image bearing surface to bear an image thereon. The transferer forms a transfer section between the transferer and the image bearer, to transfer the image onto a recording medium. The guide is disposed upstream from the transfer section in a delivery direction of the recording medium, to guide the recording medium toward the transfer section. The two rotators are disposed upstream from the transfer section in a moving direction of the image bearer and in contact with a non-image bearing surface of the image bearer opposite to the image bearing surface, a first rotator being closer to the transfer section than a second rotator. The support supports the first rotator and the guide and adjusts a position of the first rotator and a position of the guide.

Image forming apparatus with a support to adjust a rotator and a guide

A roller member includes a cored bar, an elastic layer, a first high resistance member, and a second high resistance member. The elastic layer is disposed on an outer circumferential face of the cored bar. The cored bar has a projecting portion projecting beyond a range in which the elastic layer is disposed, toward an axial end of the cored bar. The first high resistance member is made of a high-resistance material having a higher electrical resistance than an electrical resistance of the cored bar. The first high resistance member is fitted to the projecting portion. The second high resistance member is made of a high-resistance material having a higher electrical resistance than an electrical resistance of the cored bar. The second high resistance member fills a space between the first high resistance member and the elastic layer.

Roller member including a first and second high resistance member and image forming apparatus including the roller member

An image forming apparatus includes an image bearer; a toner image forming device; an intermediate transferor; a primary transfer power source; a secondary transfer nip forming device; and a secondary transfer power source to output a secondary transfer bias. One of two peak values of the secondary transfer bias is a transfer peak value to provide a greater transfer-directional force to move toner from the intermediate transferor toward the recording medium in the secondary transfer nip. An absolute value of the transfer peak value is greater than an absolute value of the primary transfer bias.

Image forming apparatus and transfer bias control

An image forming apparatus includes a plurality of image bearers, a transfer bias member, and a power source. When the transfer bias member transfers a color toner image onto a recording sheet, a second peak value of a peak-to-peak of a transfer bias, which is smaller than a first peak value of the peak-to-peak in an electrostatic force to move toner from the image bearers or an intermediate transfer body to the recording sheet, is zero or has a first polarity to generate the electrostatic force in a transfer direction to move toner from the image bearers or the intermediate transfer body to the recording sheet. When the transfer bias member transfers a monochromatic toner image including only black toner onto the recording sheet, the second peak value is zero or has a second polarity to generate an electrostatic force in an opposite direction to the transfer direction.

Image forming apparatus

An image forming apparatus includes a rotatable image bearer, a toner image forming device, a transfer device, a transfer bias power source, and a cleaner. The toner image forming device is to form a toner image on the image bearer. The transfer device contacts a surface of the image bearer to form a transfer nip between the transfer device and the image bearer. The transfer bias power source is to output a transfer bias to transfer the toner image from the image bearer onto a recording medium in the transfer nip. The cleaner is disposed downstream from the transfer nip in a direction of rotation of the image bearer, to electrostatically attract and remove toner from the surface of the image bearer to a surface of the cleaner. The transfer bias includes an alternating current component.

An image forming apparatus, including an image bearer configured to bear a toner image; a transfer device disposed opposing to the image bearer; and a transfer bias power source. The transfer bias power source is configured to output a transfer bias to transfer the toner image onto a recording medium. The transfer bias is a superimposed bias that cyclically alternates between a transfer-directional bias to transfer the toner image from the image bearer onto the recording medium and an opposite-directional bias in an opposite direction of the transfer direction. A ratio of a time period of application of the opposite-directional bias to a total time period of one cycle of the output transfer bias is greater than 50%. The transfer bias power source changes a value of a direct current voltage in the superimposed bias according to a linear velocity of the image bearer.

An image forming apparatus includes a toner image forming unit, a nip formation member, a transfer power source, an information acquisition device, and a controller. The information acquisition device acquires specific information that specifies whether a recording sheet as a transfer target of a toner image is an uneven surface sheet having an uneven surface. The controller outputs a bias including a superimposed voltage, in which an alternating current (AC) voltage is superimposed on a direct current (DC) voltage, as a transfer bias from the transfer power source when the specific information acquired by the information acquisition device is not information corresponding to the uneven surface sheet and to output a bias including only the DC voltage as the transfer bias from the transfer power source when the specific information is the information corresponding to the uneven surface sheet.

Image forming apparatus that adjusts a transfer bias according to surface properties of a transfer target

An image forming apparatus includes an image bearer, a transfer member, and a power source. The image bearer includes a plurality of layers. The transfer member forms a transfer nip between the image bearer and the transfer member. The power source outputs a transfer bias to transfer a toner image from the image bearer onto a recording sheet in the transfer nip. The transfer bias alternates between a transfer-side bias that causes the toner image to move from the image bearer to the recording sheet, and an opposite-side bias different from the transfer-side bias. A duty ratio of a time period, during which the opposite-side bias is output, relative to one cycle of a waveform, is greater than 50%.

An image forming apparatus includes an image bearer having an image bearing face to bear an image thereon; a transferer disposed opposing the image bearer, to transfer the image from the image bearing face onto a recording medium at a transfer section between the transferer and the image bearer; a first guide disposed upstream from the transfer section in a direction of delivery of the recording medium, to guide the recording medium to the transfer section; and a second guide upstream from the first guide and spaced away from the first guide, to guide the recording medium to the transfer section. Each of the first guide and the second guide extends in a lateral direction perpendicular to the direction of delivery. A leading end of the second guide in the direction of delivery is inclined from one end to the other end of the second guide in the lateral direction.

A cleaning device includes an upstream cleaner, an upstream cleaner, and a collection member. The upstream cleaner is configured to remove toner from a surface of a cleaning target. The downstream cleaner is disposed downstream from the upstream cleaner in a direction of movement of the surface of the cleaning target. The downstream cleaner is configured to remove toner from the surface of the cleaning target. The collection member is configured to collect toner from the downstream cleaner.

Cleaning device and image forming apparatus incorporating same

An image forming apparatus includes a belt-shaped image bearer, a transferer, a guide unit, and a plurality of contact members. The belt-shaped image bearer has an image bearing surface to bear an image thereon. The transferer forms a transfer section between the transferer and the image bearer, to transfer the image onto a recording medium. The guide unit is disposed upstream from the transfer section in a delivery direction of the recording medium, to guide the recording medium toward the transfer section. The plurality of contact members are disposed side by side at positions opposing the guide unit and in contact with a non image bearing surface of the image bearer opposite to the image bearing surface.

Image forming apparatus including contact members disposed side by side at positions opposing a guide unit

An image forming apparatus includes an image bearer, a transfer device contacting the image bearer to form a transfer portion, a transfer bias power source, and a controller. A ratio of a time period of application of the opposite-directional bias to a total time period of one cycle of the AC component of the superimposed bias is greater than 50%. A ratio of a value of the DC component of the superimposed bias output within a region ranging from a leading end of the recording medium to a predetermined length to a value of the DC component of the superimposed bias output outside the region is greater than a ratio of a value of the AC component of the superimposed bias output within the region to a value of the AC component of the superimposed bias output outside the region.

An image forming apparatus includes an image bearer, a toner image forming device, a nip forming device, a power source, a controller, and a temperature-and-humidity detector. The toner image forming device forms a toner image on the image bearer. The nip forming device contacts the image bearer to form a transfer nip. The power source outputs a transfer bias, in which an alternating current component is superimposed on a direct current component, to transfer the toner image onto a recording medium interposed in the transfer nip. The temperature-and-humidity detector detects a temperature and humidity. The controller controls the power source to output the transfer bias including the direct current component with a smaller absolute value as at least one of the detected temperature and humidity increases.

Image forming apparatus controlling transfer bias based on temperature and humidity

A cleaning device includes a cleaner, a casing, and an exit seal. The cleaner is configured to remove toner from a cleaning target. The casing accommodates the cleaner. The exit seal is attached to the casing and has a free end contacting the cleaning target at a position downward from the cleaner in a direction of movement of the cleaning target and an attached end attached to the casing. A space is disposed between a surface of the cleaning target and an opposite face of the exit seal opposite the cleaning target. The space includes an opening at a lateral end of the exit seal. The exit seal contacts the cleaning target from a trailing direction of the exit seal and seals the opening at at least an attached end side of the exit seal.

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Kanagawa, Japan

Tatsuya Ohsugi