Abstract: An image forming apparatus includes an image bearing member, a conductive member, a bias application device, and a control portion. The image bearing member has a photosensitive layer formed on an outer peripheral surface thereof. The conductive member is disposed so as to make contact with an inner peripheral surface of the image bearing member and has a dielectric property. The bias application device applies a bias including an alternating current bias to the conductive member. The control portion controls the bias application device. The image forming apparatus is capable of executing a heating-up mode in which an alternating current bias having a peak-to-peak value twice or more as large as a discharge start voltage between the conductive member and the image bearing member is applied to the conductive member to cause the surface of the image bearing member to be heated up.

Abstract: An image forming apparatus includes an image bearing member, a first conductive member, a bias application device, and a control portion, and performs image formation on a surface of the image bearing member while making the image bearing member rotate. The image forming apparatus is capable of executing a heating-up mode in which, at the time of non-image formation, in a state where the image bearing member is made to rotate at a velocity lower than that used at the time of image formation, an alternating current bias having a frequency higher than that used at the time of image formation and a peak-to-peak value twice or more as large as a discharge start voltage between the first conductive member and the image bearing member is applied to the first conductive member to cause a surface of the image bearing member to be heated up.

Abstract: An image forming apparatus has an image carrying body, a first electrically conductive member, a bias application device, and a controller. The first electrically conductive member makes contact with the photosensitive layer of the image carrying body The bias application device applies a bias containing an AC bias to the first electrically conductive member. The controller controls the bias application device. The image forming apparatus can execute, while no image formation is being performed, a temperature raising mode in which, with the first electrically conductive member in contact with the image carrying body outside the image formation region, an AC bias having a peak-to-peak value twice as high as the discharge start voltage between the first electrically conductive member and the image carrying body is applied to the first electrically conductive member to raise the temperature of the surface of the image carrying body.

Abstract: The present invention provides an image forming apparatus, including: an image carrier configured by a positively charged single-layer electrophotographic photosensitive body; a charging device which is based on a contact charging method for charging a circumferential surface of the image carrier while making contact with the circumferential surface of the image carrier; and a transfer unit which transfers a toner image on the circumferential surface of the image carrier to a transfer receiving body by gripping the transfer receiving body with the image carrier, wherein the transfer unit includes an application unit to which a transfer bias is applied, and a region having a volume resistivity of 107 to 109 ?·cm exists between the image carrier and the application unit.

Abstract: An image forming apparatus includes a positively-charged single layer type electrophotographic photoreceptor, a charging device with a contact charging roller for charging a surface of the photoreceptor and an exposure device for exposing the charged surface of the photoreceptor to light to form an electrostatic latent image thereon. A developing device develops the electrostatic latent image into a toner image and a transfer device transfers the toner image to a transferred body. The charging roller is made of electrically conductive rubber having an Asker-C rubber hardness of 62 to 81°. A roller surface roughness of the charging roller has an average distance (Sm) between asperity peaks on a cross-sectional curve of 55 to 130 ?m and that a ten-point average roughness (Rz) is 9 to 19 ?m. The image forming apparatus is capable of preventing carrier trapping, film peeling and uneven charging in the photoreceptor.

Abstract: An image-forming apparatus is equipped with a neutralization light source that is disposed between a primary transfer position and the cleaning unit, in a direction of rotation of the first image carrier that composes the image-forming unit; irradiates a first neutralization light from a position opposing the primary transfer position on a first image carrier up to a position opposing the cleaning unit; and irradiates a second neutralization light from a position opposing the developer unit for a second image carrier that composes an image-forming unit disposed adjacent to the image-forming unit at a downstream side in the direction of transfer belt rotation, up to a position opposite the primary transfer position.

Abstract: An image forming apparatus includes an image carrier, a charge roller, a cleaning brush and a distance changing mechanism. The charge roller includes a surface having protrusions and depressions and to electrically charge the image carrier. The cleaning brush includes a brush part cleaning the surface of the charge roller and a main body part supporting the brush part. The brush part includes a top end part and a belly part being nearer to the main body part than the top end part. The distance changing mechanism changes a distance between the charge roller and main body part so that, by adjusting the distance to a first distance, the top end part contacts with the depression and, by adjusting the distance to a second distance shorter than the first distance, the belly part contacts with the protrusion.

Abstract: An image forming apparatus has: a positively-charged single layer type electrophotographic photoreceptor; a charging device with a contact charging roller for charging a surface of the photoreceptor; an exposure device for exposing the charged surface to light to form an electrostatic latent image on the surface of the photoreceptor; a developing device for developing the electrostatic latent image into a toner image; and a transfer device for transferring the toner image to a transferred body. The photoreceptor has a conductive substrate and a photosensitive layer that contains a charge generating agent, a charge transport agent and a binder resin. The binder resin has a yield point strain of 9 to 29%, and the contact charging roller has a conductive layer with a thickness of 1 mm to 3 mm. The image forming apparatus is environmentally responsive and having a long-lasting positively-charged single layer type photoreceptor and charging roller.

Abstract: An image forming apparatus includes a positively-charged single layer type electrophotographic photoreceptor, a charging device with a contact charging roller for charging a surface of the photoreceptor and an exposure device for exposing the charged surface of the photoreceptor to light to form an electrostatic latent image thereon. A developing device develops the electrostatic latent image into a toner image and a transfer device transfers the toner image to a transferred body. The charging roller is made of electrically conductive rubber having an Asker-C rubber hardness of 62 to 81°. A roller surface roughness of the charging roller has an average distance (Sm) between asperity peaks on a cross-sectional curve of 55 to 130 ?m and that a ten-point average roughness (Rz) is 9 to 19 ?m. The image forming apparatus is capable of preventing carrier trapping, film peeling and uneven charging in the photoreceptor.

Abstract: A cleaning device includes a rotary member, a sheet member, and a toner conveying member. The rotary member is held in contact with a cylindrical surface of an image carrier above a rotation axis of the image carrier. The sheet member is in contact at a distal end thereof with the cylindrical surface of the image carrier above the rotation axis of the image carrier and upstream of a contact position of the rotary member with the cylindrical surface of the image carrier in a direction of rotation of the image carrier. The toner conveying member is disposed above the sheet member and facing the peripheral surface of the rotary member.

Abstract: An image forming apparatus includes a positively-charged single layer type electrophotographic photoreceptor, a charging device with a contact charging roller for charging a surface of the photoreceptor and an exposure device for exposing the charged surface of the photoreceptor to light to form an electrostatic latent image thereon. A developing device develops the electrostatic latent image into a toner image and a transfer device transfers the toner image to a transferred body. The charging roller is made of electrically conductive rubber having an Asker-C rubber hardness of 62 to 81°. A roller surface roughness of the charging roller has an average distance (Sm) between asperity peaks on a cross-sectional curve of 55 to 130 ?m and that a ten-point average roughness (Rz) is 9 to 19 ?m. The image forming apparatus is capable of preventing carrier trapping, film peeling and uneven charging in the photoreceptor.

Abstract: An image forming apparatus has first and second image carriers that are configured by positively-charged single layer type electrophotographic photoreceptors, and a controller that controls an operation for charging or destaticizing circumferential surfaces of these image carriers. The controller switches between a first mode for causing the first and second image carriers to perform image formation while rotating these image carriers, and a second mode for causing only the first image carrier to perform image formation while rotating the first and second image carriers. In the second mode, the second image carrier is applied with a charging bias and subjected to a destaticizing operation without undergoing a developing operation. The first image carrier is applied with the charging bias and subjected to the developing operation and the destaticizing operation.

Abstract: An image forming apparatus, having: an image carrier configured by a positively charged single-layer electrophotographic photosensitive body; a charging device which is based on a contact charging method for charging a circumferential surface of the image carrier while making contact with the circumferential surface of the image carrier; a developing roller which is disposed so as to oppose the image carrier and carry and convey toner on the circumferential surface; and a voltage application unit which applies a developing bias to the developing roller, wherein the frequency of an AC component of the developing bias applied by the voltage application unit is 2.6 to 4.2 kHz.

Abstract: An image forming apparatus has: a positively-charged single layer type electrophotographic photoreceptor; a charging device with a contact charging roller for charging a surface of the photoreceptor; an exposure device for exposing the charged surface to light to form an electrostatic latent image on the surface of the photoreceptor; a developing device for developing the electrostatic latent image into a toner image; and a transfer device for transferring the toner image to a transferred body. The photoreceptor has a conductive substrate and a photosensitive layer that contains a charge generating agent, a charge transport agent and a binder resin. The binder resin has a yield point strain of 9 to 29%, and the contact charging roller has a conductive layer with a thickness of 1 mm to 3 mm. The image forming apparatus is environmentally responsive and having a long-lasting positively-charged single layer type photoreceptor and charging roller.

Abstract: The present invention provides an image forming apparatus, including: an image carrier configured by a positively charged single-layer electrophotographic photosensitive body; a charging device which is based on a contact charging method for charging a circumferential surface of the image carrier while making contact with the circumferential surface of the image carrier; and a transfer unit which transfers a toner image on the circumferential surface of the image carrier to a transfer receiving body by gripping the transfer receiving body with the image carrier, wherein the transfer unit includes an application unit to which a transfer bias is applied, and a region having a volume resistivity of 107 to 109 ?·cm exists between the image carrier and the application unit.

Abstract: An image forming apparatus includes a positively-charged single layer type electrophotographic photoreceptor, a charging device with a contact charging roller for charging a surface of the photoreceptor and an exposure device for exposing the charged surface of the photoreceptor to light to form an electrostatic latent image thereon. A developing device develops the electrostatic latent image into a toner image and a transfer device transfers the toner image to a transferred body. The charging roller is made of electrically conductive rubber having an Asker-C rubber hardness of 62 to 81°. A roller surface roughness of the charging roller has an average distance (Sm) between asperity peaks on a cross-sectional curve of 55 to 130 ?m and that a ten-point average roughness (Rz) is 9 to 19 ?m. The image forming apparatus is capable of preventing carrier trapping, film peeling and uneven charging in the photoreceptor.

Abstract: An image forming apparatus of the present invention has first and second image carriers that are configured by positively-charged single layer type electrophotographic photoreceptors, and a controller that controls an operation for charging or destaticizing the circumferential surfaces of these image carriers. The controller switches between a first mode for causing the first and second image carriers to perform image formation while rotating these image carriers, and a second mode for causing only the first image carrier to perform image formation while rotating the first and second image carriers. In the second mode, the second image carrier is applied with a charging bias and subjected to a destaticizing operation without undergoing a developing operation. The first image carrier is applied with the charging bias and subjected to the developing operation and the destaticizing operation.

Abstract: An image forming apparatus, having: an image carrier configured by a positively charged single-layer electrophotographic photosensitive body; a charging device which is based on a contact charging method for charging a circumferential surface of the image carrier while making contact with the circumferential surface of the image carrier; a developing roller which is disposed so as to oppose the image carrier and carry and convey toner on the circumferential surface; and a voltage application unit which applies a developing bias to the developing roller, wherein the frequency of an AC component of the developing bias applied by the voltage application unit is 2.6 to 4.2 kHz.

Abstract: An image-forming apparatus is equipped with a neutralization light source that is disposed between a primary transfer position and the cleaning unit, in a direction of rotation of the first image carrier that composes the image-forming unit; irradiates a first neutralization light from a position opposing the primary transfer position on a first image carrier up to a position opposing the cleaning unit; and irradiates a second neutralization light from a position opposing the developer unit for a second image carrier that composes an image-forming unit disposed adjacent to the image-forming unit at a downstream side in the direction of transfer belt rotation, up to a position opposite the primary transfer position.

Abstract: An image forming apparatus includes: a photoreceptor; a charging portion; an exposure portion; a developing portion; a transfer body; a cleaning portion; and a control portion. The charging portion charges the photoreceptor. The exposure portion forms an electrostatic latent image on the photoreceptor. The developing portion forms a developed image on the photoreceptor. The developed image thus formed is primarily transferred to the transfer body and the transfer body secondarily transfers the developed image thus primarily transferred to a predetermined recording medium. The cleaning portion cleans the transfer body. The control portion performs control to: form a cleaning developed image on the photoreceptor outside of a paper feeding width and inside of a developing width, primarily transfer the cleaning developed image to the transfer body, and make the cleaning portion clean the cleaning developed image thus primarily transferred.