Abstract: For an electrostatic latent image formed on an image carrier (31b), besides an operation forming an “image forming electrostatic latent image” used to form the primary image, an operation is executed that forms an “electrostatic latent image for removing developer” for removing developer that resides on a developer supply member (53a) for a predetermined time period onto the image carrier (31b). Thus, developer is nearly eliminated from residing on this developer supply member (53a) in an overcharged state for a long period of time, and generation of a fogged image is avoided as much as possible.

Abstract: A fixing device of the present invention includes: an external heating belt which is to contact with a surface of a fixing roller so as to heat up the fixing roller; and a cleaning member (a scraper and/or cleaning pad) which is to contact with the external heating belt. The cleaning pad which is impregnated with silicone oil is to contact with a surface of the external heating belt, thereby applying the silicone oil (release agent) to the surface of the external heating belt. This makes it possible to prevent generation of an offset.

Abstract: No covering layer is provided onto that abutting surface of an external heating belt which has contact with a cleaning member. Accordingly, a belt substrate is exposed and has contact with the cleaning member. This suppresses the occurrence of offset in a fixing device including (i) the external heating belt for having contact with the surface of the fixing roller so as to heat a fixing roller, and (ii) the cleaning member having contact with the external heating belt.

Abstract: In a fixing device including (i) an external heat belt which abuts against a surface of a fixing roller so as to heat the fixing roller and (ii) a cleaning member which abuts against the external heat belt, a fixing temperature, which is a surface temperature of the fixing roller during a fixing process, is set per group into which recording media to be subjected to the fixing process are divided according to their widths in a direction of a rotary axis of the fixing roller, in such a way that the fixing temperature is set to a lower temperature for a group of narrower widths. This makes it possible to prevent a reduction in releasability of the fixing roller caused by a material, which is scraped off from the external heat belt by the cleaning member and then adhered to the fixing roller, thereby preventing the high-temperature offset.

Abstract: A charging apparatus having a corona electrode is provided which exhibits high durability against ozone and moisture in the air, which can charge a surface of a photoreceptor drum stably throughout the life of an image forming apparatus, and which can be manufactured at a low cost. In a charging apparatus including corona electrode having a flat plate section and a pointed projection section, a support member, a shield case, and a grid electrode, a coating layer including a material different from the material of the corona electrode is formed at least on part of the surface of pointed projections constituting the pointed projection section.

Abstract: An electrostatic charger according to the present invention includes a needle electrode, a support, and a cleaning member. The needle electrode has a linear array of needles. The support can move along the linear array. The cleaning member is supported by the support rotatably on an axis perpendicular to the linear array. While the support is moving with the cleaning member along the linear array, the cleaning member rotates, with the needles sinking in order into and subsequently coming in order out of the cleaning member. When the cleaning member makes each rotation while moving with the support, some of the needles sink in positions into the cleaning member where any other needles did not sink when the cleaning member made the previous rotation.

Abstract: An image forming apparatus includes a photoreceptor, a cleaning unit, an exposing unit, a developing unit, and a control section. On a circumferential surface thereof, the photoreceptor has an image area to have contact with a record medium in an image forming process, and a non-image area. The cleaning unit has a blade in contact with the image and non-image areas. The exposing unit forms an electrostatic latent image on the surface by irradiating the surface along a fast scanning direction with light modulated according to image data supplied by the control section. The data includes primary image data for modulating light to irradiate the image area with. The developing unit develops the latent image by applying developer to the surface. The control section performs an image addition processing in which secondary image data for modulating light to irradiate the non-image area with is added to the primary image data.

Abstract: A developer collecting apparatus includes a positioning frame for determining a mounting position of a photoreceptor onto a casing; a waste developer container in which waste developer eliminated by cleaning section is stored; and a container mounting section for mounting the waste developer container so as to be removable from the positioning frame and holding the waste developer container so as to be angularly displaceable with respect to the positioning frame. Further, the container mounting section includes a container holding member that is disposed so as to be angularly displaceable with respect to the positioning frame, for holding the waste developer container; a cam member disposed so as to be movable in a direction orthogonal to a direction in which the container holding member is angularly displaced; and an elastic member for biasing the cam member to the container holding member with an elastic force.

Abstract: An image forming apparatus includes a transfer belt unit which has an intermediate transfer belt for supporting toner images and primary transfer rollers for pressing the intermediate transfer belt against corresponding photoreceptor drums and moves the intermediate transfer belt along the surface of each photoreceptor drum to transfer the toner images to the intermediate transfer belt. The intermediate transfer belt is formed so as to be 30 ?m to 50 ?m in average thickness, each primary transfer roller is arranged at a position, along the moving direction of the intermediate transfer belt, which is deviated downstream with respect to the moving direction from the position where the intermediate transfer belt is in contact with the photoreceptor and which is projected toward the photoreceptor drum side so as to press the intermediate transfer belt against photoreceptor with a nip pressure ranging from 10 gf/cm2 to 40 gf/cm2.

Abstract: An electrophotographic image forming apparatus is provided with a developer collecting device which collects developer removed from an image bearing member and an intermediate transfer body by a cleaning section. The developer collecting device comprises a positioning frame for determining a mounting position of the image bearing member onto an image forming apparatus main body; a waste developer container detachably mounted on the positioning frame 4, for accommodating waste developer collected by the cleaning section; and an integrated container detection section for detecting whether or not the waste developer container is mounted on the positioning frame and whether or not the waste developer container is filled up with the waste developer.

Abstract: An ozone exhaust system in an image forming apparatus having a multiple number of process printing units, includes: exhaust ducts for exhausting ozone arising in the process printing units. In the ozone exhaust system, the exhaust ducts are mainly constituted of process printing unit's side exhaust ducts provided respectively along multiple charger cases and a main exhaust duct to which the process printing unit's side exhaust ducts are connected, and the process printing unit's side exhaust ducts are constructed so that the air current that flows into the charger cases and the air current that flows from the process printing unit's side exhaust ducts into the main exhaust duct are directed in the same direction.

Abstract: An intermediate transfer unit mounting and dismounting mechanism for an image forming apparatus including a transfer belt unit that is provided as a separate structure from the apparatus body and can be mounted to and dismounted from the apparatus body, includes: a coupling/decoupling manipulator disposed at the coupling portion between the intermediate transfer unit and the apparatus body for coupling/decoupling. The coupling/decoupling manipulator includes a threaded portion to fasten the intermediate transfer unit and the apparatus body and a drive gear for transferring driving force for conveying the intermediate transfer belt. While the threaded portion is rotated to release the fastening between the transfer belt unit and the housing, the transfer belt is conveyed by the drive gear that rotates in linkage with the rotation of the threaded portion.

Abstract: A discharge unit is disposed downstream of a principal transport path of a compound machine, and a shifter function is provided in this discharge unit. By shifting the paper passage position relative to a photosensitive drum when printing the front side and the paper passage position relative to the photosensitive drum when printing the back side, the region in which the surface electric potential of the photosensitive drum increases is diminished, and the region in which photographic fog is generated is made smaller. Thus, when printing the second and subsequent sheets, even when a slight amount of displacement of the transport position of the recording paper occurs, it is possible to suppress that recording paper making contact in the photographic fog region on the photosensitive drum, and defective printing can be prevented.

Abstract: A developer collecting apparatus for collecting waste developer which is generated by cleaning residual developer remained on a photoreceptor and an intermediate transfer body, includes: a waste developer container for accommodating the waste developer; a stirring member rotatably provided in the waste developer container, for stirring the waste developer; and a driving section for giving a rotary driving force to the stirring member. The driving section of the stirring member has: a driving source; a first driving force transmitting path and a second driving force transmitting path which are coupled on the driving source, for transmitting the rotary driving force to the stirring member, and when a rotational load on the first driving force transmitting path reaches a predetermined level or more, a switch-over of transmitting path can be performed from the first driving force transmitting path to the second driving force transmitting path.

Abstract: A color image forming apparatus 1 includes: a multiple number of process printing units 20, each having an photoreceptor drum 21 for bearing a developer image formed with a toner corresponding to a different color of color-separated image information; a transfer belt 31 to which a multiple number of developer images are comprised in layers; and a transfer roller 36 for transferring the developer images that have been comprised in layers on transfer belt 31, all at once, to recording paper, wherein the multiple number of process printing units 20 are arranged along transfer belt 31, and is characterized in that among the developer images to be transferred from the photoreceptor drums 21 of multiple image forming units 20 onto transfer belt 31, the toner for the developer image of the color to be transferred first is specified to produce a base-layer of the color images of information.

Abstract: A cleaning blade for removing residual toner left on the surface of an intermediate transfer belt after the second transfer is supported integrally with movement of a tension roller. In the case where the tension roller moves to make a tension of the intermediate transfer belt constant, then, following this, the cleaning blade moves. Thus, the contact state of the cleaning blade with respect to the surface of the intermediate transfer belt is kept constant, and thus cleaning of the intermediate transfer belt can be performed stably.

Abstract: A color image forming apparatus includes: process printing units each having a photoreceptor drum; a transfer belt to which toner images are transferred; a transfer roller for transferring, as a whole, the toner images on the transfer belt to recording paper; a cleaning unit for collecting the remaining developers that have been left over on the photoreceptor drums and the transfer belt, is constructed such that a positioning sub-frame which is set with a developer collecting container for storing the collected developers and positions the process printing units relative to the housing, on one side of the apparatus body is removably attached to the housing.

Abstract: An image forming apparatus is constituted so as to be equipped with transfer apparatus(es) having transfer roller(s) electrostatically transferring development image(s) from photosensitive drum(s) to transfer medium/media, and so as to be provided with transfer medium guide unit disposed downstream in transfer medium transport path(s) from location(s) at which photosensitive drum(s) oppose transfer roller(s), and such that transfer medium guide location(s) of transfer medium guide means is/are variable.

Abstract: A charging apparatus having a corona electrode is provided which exhibits high durability against ozone and moisture in the air, which can charge a surface of a photoreceptor drum stably throughout the life of an image forming apparatus, and which can be manufactured at a low cost. In a charging apparatus including corona electrode having a flat plate section and a pointed projection section, a support member, a shield case, and a grid electrode, a coating layer including a material different from the material of the corona electrode is formed at least on part of the surface of pointed projections constituting the pointed projection section.

Abstract: An electrostatic charger according to the present invention includes a needle electrode, a support, and a cleaning member. The needle electrode has a linear array of needles. The support can move along the linear array. The cleaning member is supported by the support rotatably on an axis perpendicular to the linear array. While the support is moving with the cleaning member along the linear array, the cleaning member rotates, with the needles sinking in order into and subsequently coming in order out of the cleaning member. When the cleaning member makes each rotation while moving with the support, some of the needles sink in positions into the cleaning member where any other needles did not sink when the cleaning member made the previous rotation.