Abstract: An image forming apparatus is constituted by an image bearing member; a corona charging member including a wire; a heat generating member for generating heat by energization; a shielding member, including the heat generating member, capable of shielding a portion of the corona charging member opposing to the image bearing member from the image bearing member by being moved between the corona charging member and the image bearing member; an energization control member for controlling energization of the heat generating member; and moving member for moving the shielding member to a first position at which the shielding member shields the portion and a second position retracted from the first position. When the shielding member is located at the first position, at least a part of the heat generating member is disposed between the corona charging member and the image bearing member.

Abstract: In an image forming apparatus, an exposure device performs exposure on a non-image area of image pattern, performs an exposure on the image area in an exposure amount lower than the non-image area or does not perform exposure, and an exposure amount control device controls, with respect to pixels having the same density data, an exposure amount given by an exposure device to be smaller in a first portion, which is a thin-line of a width that is equal to or less than a predetermined number of pixels or which is an isolated dot of widths that are equal to or less than the predetermined number of pixels in two directions substantially orthogonal to each other, than in a second portion which is a line of a width exceeding the predetermined number or a surface of widths that exceed the predetermined number in two directions substantially orthogonal to each other.

Abstract: An image forming apparatus with a plurality of reading units, which is capable of easily adding a recording sheet type usable for calibration. Calibration is executed using a specific recording sheet. Gradation patterns are formed on a recording sheet of a sheet type to be added, and are read by a reader unit. A first conversion table is configured based on information on the read image. A second conversion table is configured based on the first conversion table. When the reader unit is used to perform calibration using the added recording sheet, image forming conditions are set based on information on the image read by the reader unit and the first conversion table, and when the color sensor is used, the image forming conditions are set based on information on the image read by the color sensor and the second conversion table.

Abstract: A determination unit determines density correction characteristics to be applied to correct density characteristics based on a reading result obtained by a reading unit. A measuring unit measures a density value of the image pattern formed on the image carrier by the image forming unit at the first image forming speed by applying the density correction characteristics. A reference density value storage unit stores, as a reference density value, the density value of the image pattern measured by the measuring unit. A creation unit creates modification data to modify the density correction characteristics for a second image forming speed from a difference between a density value of an image pattern formed on the image carrier by the image forming unit at the second image forming speed by applying the density correction characteristics, and the reference density value stored in the reference density value storage unit.

Abstract: In an image forming apparatus, an exposure device performs exposure on a non-image area of image pattern, performs an exposure on the image area in an exposure amount lower than the non-image area or does not perform exposure, and an exposure amount control device controls, with respect to pixels having the same density data, an exposure amount given by an exposure device to be smaller in a first portion, which is a thin-line of a width that is equal to or less than a predetermined number of pixels or which is an isolated dot of widths that are equal to or less than the predetermined number of pixels in two directions substantially orthogonal to each other, than in a second portion which is a line of a width exceeding the predetermined number or a surface of widths that exceed the predetermined number in two directions substantially orthogonal to each other.

Abstract: An image forming apparatus comprising an exposure device for exposing an image bearing member to light in accordance with monochromatic image data provided by color separation of inputted multi-color image data to form an electrostatic latent image; a control device for calculating an exposure amount of each pixel of the monochromatic image data to expose the image bearing member with the calculated exposure amount; wherein the control device includes a monochromatic correcting device for calculating a correction amount in accordance with a pixel value of a pixel around a target pixel of the monochromatic image data to correct an exposure amount of the target pixel on the basis of the calculated amount; wherein the control device includes a multi-color correcting device for providing a coefficient for correction of the exposure amount on the basis of the multi-color image data; wherein the monochromatic correcting device controls the exposure amount using the coefficient and the correction amount provided by

Abstract: This invention provides an image forming apparatus capable of outputting, without using any special device, an image which is free from changes in density and tint even upon crisscross rotation and exhibits good proportion of a small character. To accomplish this, the pulse width of a laser emission signal is controlled at 16 levels for one dot at 600 dpi, controlling an actual image in the main scanning direction. When adjusting vertical and horizontal line widths, patch data are created by rotating an anisotropic pattern through 0° and 90° (S1 in FIG. 5). Then, a reader/scanner (15) reads each patch as density data (S2 in FIG. 5). A pulse width, that is, line width correction value at which the densities of the patch patterns rotated through 0° and 90° become equal to each other is obtained (S3 in FIG. 5).

Abstract: The present invention aims to reduce the time period of the start up operation of an image forming apparatus corresponding to an image forming apparatus operating environment. The present invention provides an image forming apparatus includes an image bearing member; a toner image forming unit for forming a toner image on the image bearing member; an image condition detection member for detecting an image condition of the image bearing member; a setting unit for setting a plurality of toner image forming conditions determined based on the output of the image condition detection member; an environment detection member for detecting an environment condition of outside air of the image forming apparatus; and a selection unit for selecting the toner image forming conditions set by the setting unit based on the output of the environment detection device from when the power is turned on to when transitioned to an image formable state.

Abstract: An image forming apparatus includes first and second image forming devices each including a rotatable drum, a charging device for charging the drum, an exposure device for exposing the drum to light, and a developing device for developing with toner an electrostatic image formed on the drum, each of the image forming devices being configured to form an image on a sheet; a gradation pattern forming device for forming a first gradation pattern on a sheet by the first image forming device and forming a second gradation pattern on the sheet by the second image forming device; a density detecting device for detecting a density of the gradation patterns formed on the sheet; a correcting device for correcting an image forming condition of each of the toner image forming means depending on an output of the density detecting device; and a potential detecting device, selectively provided to the first image forming means, capable of detecting potential of a part of an area of the drum with respect to a rotational axis d

Abstract: An image forming apparatus is constituted by an image bearing member; a corona charging member including a wire; a heat generating member for generating heat by energization; a shielding member, including the heat generating member, capable of shielding a portion of the corona charging member opposing to the image bearing member from the image bearing member by being moved between the corona charging member and the image bearing member; an energization control member for controlling energization of the heat generating member; and moving member for moving the shielding member to a first position at which the shielding member shields the portion and a second position retracted from the first position. When the shielding member is located at the first position, at least a part of the heat generating member is disposed between the corona charging member and the image bearing member.

Abstract: In an image forming apparatus, an exposure device performs exposure on a non-image area of image pattern, performs an exposure on the image area in an exposure amount lower than the non-image area or does not perform exposure, and an exposure amount control device controls, with respect to pixels having the same density data, an exposure amount given by an exposure device to be smaller in a first portion, which is a thin-line of a width that is equal to or less than a predetermined number of pixels or which is an isolated dot of widths that are equal to or less than the predetermined number of pixels in two directions substantially orthogonal to each other, than in a second portion which is a line of a width exceeding the predetermined number or a surface of widths that exceed the predetermined number in two directions substantially orthogonal to each other.

Abstract: An image forming apparatus is constituted by an image bearing member; a corona charging member including a wire; a heat generating member for generating heat by energization; a shielding member, including the heat generating member, capable of shielding a portion of the corona charging member opposing to the image bearing member from the image bearing member by being moved between the corona charging member and the image bearing member; an energization control member for controlling energization of the heat generating member; and moving member for moving the shielding member to a first position at which the shielding member shields the portion and a second position retracted from the first position. When the shielding member is located at the first position, at least a part of the heat generating member is disposed between the corona charging member and the image bearing member.

Abstract: An image heating apparatus has a coil for generating magnetic flux, a rotatable heat generation member which generates heat by magnetic flux, a temperature detecting member for detecting a temperature of the heat generation member, an energization controller portion for controlling energization to the coil on the basis of an output of the temperature detecting member, a first magnetic flux shielding portion for blocking, in a first magnetic flux adjustment position, the magnetic flux directed toward a central portion of heat generation member, while permitting the magnetic flux directed to an end portion, and a second magnetic flux shielding portion for blocking, in a second magnetic flux adjustment position, the magnetic flux directed toward an end portion of the heat generation member, a moving unit for moving the first magnetic flux shielding portion and the second magnetic flux shielding portion, and a recovery operation controller portion for retracting the second magnetic flux shielding portion from the

Abstract: This invention provides an image forming apparatus capable of outputting, without using any special device, an image which is free from changes in density and tint even upon crisscross rotation and exhibits good proportion of a small character. To accomplish this, the pulse width of a laser emission signal is controlled at 16 levels for one dot at 600 dpi, controlling an actual image in the main scanning direction. When adjusting vertical and horizontal line widths, patch data are created by rotating an anisotropic pattern through 0° and 90° (S1 in FIG. 5). Then, a reader/scanner (15) reads each patch as density data (S2 in FIG. 5). A pulse width, that is, line width correction value at which the densities of the patch patterns rotated through 0° and 90° become equal to each other is obtained (S3 in FIG. 5).

Abstract: An image forming apparatus is constituted by an image bearing member; a corona charging member including a wire; a heat generating member for generating heat by energization; a shielding member, including the heat generating member, capable of shielding a portion of the corona charging member opposing to the image bearing member from the image bearing member by being moved between the corona charging member and the image bearing member; an energization control member for controlling energization of the heat generating member; and moving member for moving the shielding member to a first position at which the shielding member shields the portion and a second position retracted from the first position. When the shielding member is located at the first position, at least a part of the heat generating member is disposed between the corona charging member and the image bearing member.

Abstract: An electromagnetic induction heating apparatus capable of uniformize a temperature distribution in a longitudinal direction of an induction heating member includes: an exciting coil (magnetic flux generation means); a fixation roller (induction heating member) for generating heat by electromagnetic induction heating by action of magnetic flux generated by the exciting coil the induction heating member heating a material to be heated through heat generation thereof by introducing the material to be heated into a heating portion and conveying the material to be heated in contact with the fixation roller; and magnetic flux shielding plate (magnetic flux adjusting means) for changing a distribution of a density of an effective magnetic flux which is the magnetic flux generated by the exciting coil and actable on the fixation roller, in a longitudinal direction of the heating portion perpendicular to a conveyance direction of the material to be heated.

Abstract: A heating apparatus has an induction heat generation member for electromagnetic induction heat generation by the magnetic flux at a heating portion, wherein a material to be heated is introduced to the heating portion and is fed in direct contact with the induction heat generation member or in contact to a heat transfer material for receiving heat from the induction heat generation member; a magnetic flux adjusting unit for changing a distribution of a density of an effective magnetic flux actable on the induction heat generation member with respect to a widthwise direction perpendicular to a feeding direction of the material to be heated; wherein magnetic flux adjusting unit has a plurality of steps which extend in the feeding direction and are selectable to change the distribution of the magnetic flux density in response to a width of the material measured in the widthwise direction, wherein a step of the steps for a largest magnetic flux adjustment region measured in the widthwise direction is largest.

Abstract: An image forming apparatus has an image forming unit; a heating rotatable member; a magnetic flux generator for generating a magnetic flux for induction heat generation in the heating rotatable member; a controller for controlling a temperature of the heating rotatable member; a temperature detector for detecting a temperature of the heating rotatable member at a predetermined region; magnetic flux confinor for confining the magnetic flux from the magnetic flux generator in accordance with an output of the temperature detector; and a moving unit for movement the magnetic flux confinor between a magnetic-flux-confinement position and a n on-magnetic-flux-confinement position, wherein when the output of the temperature detector indicates a temperature outside a predetermined temperature range, an image forming operation is interrupted, and executes operation of the moving unit to move the magnetic flux confinor to the non-magnetic-flux-confinement position and restoring operation to restore the temperature of t

Abstract: An image heating apparatus includes a heating rotatable member for heating an image on a recording material in a heating nip; a magnetic flux generator for generating a magnetic flux for induction heat generation in the heating rotatable member; a magnetic flux confining device for confining the magnetic flux directed toward a predetermined region of the heating rotatable member from the magnetic flux generator; and a moving device for repeatedly moving the magnetic flux confining device during a heating operation between the operating position and a retracted position retracted from the operation position, when the recording material which has a predetermined width overlapping with a part of the predetermined region is continuously heated by the apparatus.

Abstract: An image heating apparatus has a magnetic flux generator for generating a magnetic flux; a heat generation member for generating heat by the magnetic flux generator; a magnetic flux adjustor for adjusting an effective magnetic flux region toward the heat generation member with respect to a widthwise direction which is perpendicular to a feeding direction of a material to be heated, wherein the material to be heated is heated by heat generation of the heat generation means; wherein the magnetic flux adjustor includes a magnetic flux adjusting member and moving member for moving the magnetic flux adjusting member, and wherein a temperature distribution in theat generation member with respect to the widthwise direction is adjusted by moving the flux adjusting member to a predetermined magnetic flux adjusting position by the moving member; and a discriminator for discriminating whether the effective magnetic flux region corresponds to a size of the material to be heated or not when the magnetic flux adjusting mem