Abstract: A charging device includes a charging member disposed so as to rotate in contact with a surface of an image carrier to charge the image carrier surface, a bias voltage applying unit that applies a bias voltage to the charging member, the bias voltage having an AC voltage superimposed on a DC voltage, a DC current detector that detects a DC current flowing between the image carrier and the charging member, a filter that extracts only a specific component from the DC current detected by the DC current detector, and a controller that controls at least one of an AC voltage and an AC current to be applied to the charging member in accordance with an amount of variation of the specific component extracted from the DC current by the filter.

Abstract: An image forming apparatus includes a rotatable image carrying member, on a surface of which an electrostatic latent image is formed, and a charging roll that is in contact with the image carrying member to charge the surface of the image carrying member to a prescribed potential. The charging roll has, in non-image forming areas in both end parts in an axial direction of the charging roll, large diameter parts having a larger outer diameter than an outer diameter of a center part of the charging roll, and small diameter parts having a smaller outer diameter than the outer diameter of the center part inside the large diameter parts in the axial direction. Differences in outer diameter of the large diameter part and the small diameter part from the outer diameter of the center part each is approximately 0.25% or less of the outer diameter of the center part.

Abstract: An image forming apparatus includes a rotatable image carrier, a charging roll and a support member. The image carrier has a surface on which an electrostatic latent image is to be formed. The charging roll follows rotation of the image carrier. The charging roll charges the surface of the image carrier at a predetermined potential. The support member is in contact with the charging roll at a contact point. The contact point is on a downstream of a nip portion between the image carrier and the charging roll in a rotation direction of the charging roll. The contact point is on an upstream of a plane, which contains an axis line of the charging roll and is perpendicular to a plane defined by an axis line of the image carrier and the axis line of the charging roll.

Abstract: A charging device includes a charging member that charges a body to be charged; a detector that detects an AC component of a current flowing through the charging member; an integration section that integrates the AC component of the current detected by the detector; a controller that controls the current flowing through the charging member, according to a result of integration executed by the integration section; a periodic signal generating section that generates a periodic signal having a cycle period corresponding to a cycle period of the AC component; and an integration period adjusting section that adjusts a period of integration executed by the integration section, with reference to the periodic signal.

Abstract: A charging device includes a charging member that charges a body to be charged; a detector that detects an AC component of a current flowing through the charging member; an integration section that integrates the AC component of the current detected by the detector; a controller that controls the current flowing through the charging member, according to a result of integration executed by the integration section; a periodic signal generating section that generates a periodic signal having a cycle period corresponding to a cycle period of the AC component; and an integration period adjusting section that adjusts a period of integration executed by the integration section, with reference to the periodic signal.

Abstract: A charging device includes a charging member disposed so as to rotate in contact with a surface of an image carrier to charge the image carrier surface, a bias voltage applying unit that applies a bias voltage to the charging member, the bias voltage having an AC voltage superimposed on a DC voltage, a DC current detector that detects a DC current flowing between the image carrier and the charging member, a filter that extracts only a specific component from the DC current detected by the DC current detector, and a controller that controls at least one of an AC voltage and an AC current to be applied to the charging member in accordance with an amount of variation of the specific component extracted from the DC current by the filter.

Abstract: An image forming apparatus includes a rotatable image carrier, a charging roll and a support member. The image carrier has a surface on which an electrostatic latent image is to be formed. The charging roll follows rotation of the image carrier. The charging roll charges the surface of the image carrier at a predetermined potential. The support member is in contact with the charging roll at a contact point. The contact point is on a downstream of a nip portion between the image carrier and the charging roll in a rotation direction of the charging roll. The contact point is on an upstream of a plane, which contains an axis line of the charging roll and is perpendicular to a plane defined by an axis line of the image carrier and the axis line of the charging roll.

Abstract: An image forming apparatus includes a rotatable image carrying member, on a surface of which an electrostatic latent image is formed, and a charging roll that is in contact with the image carrying member to charge the surface of the image carrying member to a prescribed potential. The charging roll has, in non-image forming areas in both end parts in an axial direction of the charging roll, large diameter parts having a larger outer diameter than an outer diameter of a center part of the charging roll, and small diameter parts having a smaller outer diameter than the outer diameter of the center part inside the large diameter parts in the axial direction. Differences in outer diameter of the large diameter part and the small diameter part from the outer diameter of the center part each is approximately 0.25% or less of the outer diameter of the center part.

Abstract: Elements of a vector sequence A·&phgr;m are sampled to be stored in a memory. In this sampling, a combination of spatial sampling and local sampling on the basis of physical phenomenon is employed. A residual minimization coefficient &agr;1m (wherein l=1, . . . , L) used for obtaining a corrected approximate value &phgr;m is approximately obtained by using elements of a vector sequence A·&phgr;k (wherein k=m−L+1, . . . , m−1) stored in the memory.

Abstract: A·U+B(U)=f, wherein A is a linear differential operator, B is a nonlinear differential operator, and f is an inhomogeneous term (source term) in a nonlinear partial differential equation to be satisfied by a physical quantity U, is solved by successive approximation. In calculation, (f−A·Um−B(Um)) is given as a nonlinear residual rr of an approximate solution Um, wherein m is the number of repeating times, and the approximate solution Um is repeatedly corrected so as to reduce a norm of a nonlinear residual rm+1 employed in a subsequent step.

Abstract: An image forming member 1 includes an image forming portion 12 for forming an image; a supported portion 10 which is rotatably supported by a bearing 14; and a driven portion 11 which receives a drive force by way of a drive force transmission member. The image forming section 12, the supported portion 10, the driven portion 11 are all made of the same base member having the same diameter. Further, the surface 10' of the supported portion 10 is supported by the bearing 14, and the surface 11' of the driven portion 11 receives the drive force.