Abstract: An image forming apparatus comprising: a controller controlling an image forming unit to form a test image, controlling a measurement unit to measure the test image on an image bearing member, and controlling a transfer unit to transfer the test image formed on the image bearing member to the sheet; a reception unit receiving a user instruction; and a second generation unit generating the conversion condition based on the user instruction and the measurement result of the test image, wherein the test image includes a first test image, a second test image, and an image indicating a position where the sheet is to be bent, and in a case where the sheet is bent along the position, a position of the first test image and a position of the second test image do not overlap with each other.

Abstract: The image forming apparatus including: a controller controlling the image forming unit to form a test image, controlling the measurement unit to measure the test image on the image bearing member, and controlling the transfer unit to transfer the test image to the sheet; a reception unit receiving a user instruction; a second generation unit generating the conversion condition based on the user instruction and the measurement result of the test image, wherein the sample image includes a first sample image, a second sample image, and a third sample image, a color difference between the first and second sample images is smaller than a threshold value, a color difference between the second and third sample images is larger than the threshold value, density of the first sample image is higher than density of the second sample image and density of the third sample image.

Abstract: An image forming apparatus comprising: a controller controlling an image forming unit to form a test image, controlling a measurement unit to measure the test image on an image bearing member, and controlling a transfer unit to transfer the test image formed on the image bearing member to the sheet; a reception unit receiving a user instruction; and a second generation unit generating the conversion condition based on the user instruction and the measurement result of the test image, wherein the test image includes a first test image, a second test image, and an image indicating a position where the sheet is to be bent, and in a case where the sheet is bent along the position, a position of the first test image and a position of the second test image do not overlap with each other.

Abstract: An image forming apparatus includes: a correction unit correcting image data based on a correction condition; an image forming unit forming an image based on the corrected image data; a transfer unit transferring the image onto a sheet; a measuring unit measuring a measuring image on an image bearing member; a converting unit converting a measurement result of the measuring image, based on a conversion condition; a first generating unit generating the correction condition based on the converted measurement result; an acquiring unit acquiring a measurement result of a test image formed on the image bearing member; a controller forming a test image on the sheet; a receiving unit receiving instruction from a user comparison of a sample image and the test image transferred on the sheet; and a second generating unit generating the conversion condition, based on the instruction and the acquired measurement result of the test image.

Abstract: A toner image for measurement of an area coverage modulation of 90% or more is formed on a photosensitive drum in a non-image formation, and a setting condition for defining a developability of a toner image in an image formation is set so that a detection result of an optical sensor detecting the toner image for measurement becomes a preset target value. The target value is set to be lower as a value of the setting condition increases from a lower side to a higher side of the developability. The target value is set so that a color difference ?E of an image having half the maximum image density obtained after the setting condition is set with respect to an image having half the maximum image density obtained after the setting condition is set in a setting mode with use of unused developer is 6.5 or less.

Abstract: An image forming apparatus includes first and second image forming devices each including a rotatable drum, a charging device, an exposure device, and a developing device, 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; a correcting device for correcting an image forming condition of each of the image forming devices; and a potential detecting device, selectively provided to the first image forming device, capable of detecting potential in order to adjust the potential of the drum.

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: 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: An image heating apparatus includes a coil for generating a magnetic flux by a current flowing therethrough; an image heating member having an electroconductive layer in which an eddy current is produced by the magnetic flux by which heat is generated, the image heating member being effective to heat an image on a recording material; an electroconductive magnetic flux adjusting member movable from a first position and a second position to decrease the eddy current produced in the image heating member by the magnetic flux; a temperature sensor for sensing a temperature of image heating member; electric power control means for control electric power supplied to the coil on the basis of an output of the temperature sensor, wherein the electric power control means changes an electric power condition to be supplied to the coil before start of the movement from the first position to the second position of magnetic flux adjusting member.

Abstract: A toner image for measurement of an area coverage modulation of 90% or more is formed on a photosensitive drum in a non-image formation, and a setting condition for defining a developability of a toner image in an image formation is set so that a detection result of an optical sensor detecting the toner image for measurement becomes a preset target value. The target value is set to be lower as a value of the setting condition increases from a lower side to a higher side of the developability. The target value is set so that a color difference ?E of an image having half the maximum image density obtained after the setting condition is set with respect to an image having half the maximum image density obtained after the setting condition is set in a setting mode with use of unused developer is 6.5 or less.

Abstract: An image forming apparatus capable of performing accurate gradation correction in a range of density where measurement by a toner density detection unit is- impossible. A printer unit forms a gradation pattern on an image bearing member. A density detection sensor detects density of the gradation pattern. A first correction value for correcting gradation of the image data is calculated based on density of the gradation pattern, detected by the density detection sensor, and a second correction value for correcting gradation of the image data is calculated based on the estimated condition of toner with which a toner image is formed on the image bearing member. An output gamma correction unit corrects density in a low density range of the toner image based on the first correction value, and corrects density in a high density range of the toner image based on the second correction value.

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: An image heating apparatus includes a coil for generating a magnetic flux by a current flowing therethrough; an image heating member having an electroconductive layer in which an eddy current is produced by the magnetic flux by which heat is generated, to heat an image on a recording material; an electroconductive magnetic flux adjusting member movable from a first position and a second position to decrease the eddy current produced in the image heating member by the magnetic flux; a sensor for sensing the temperature of the image heating member; and a controller for controlling electric power supplied to the coil on the basis of an output of the sensor. The controller changes an electric power condition to be supplied to the coil before start of the movement from the first position to the second position of magnetic flux adjusting 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: 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 includes a coil for generating a magnetic flux by a current flowing therethrough; an image heating member having an electroconductive layer in which an eddy current is produced by the magnetic flux by which heat is generated, to heat an image on a recording material; an electroconductive magnetic flux adjusting member movable from a first position and a second position to decrease the eddy current produced in the image heating member by the magnetic flux; a sensor for sensing the temperature of the image heating member; and a controller for controlling electric power supplied to the coil on the basis of an output of the sensor. The controller changes an electric power condition to be supplied to the coil before start of the movement from the first position to the second position of magnetic flux adjusting member.

Abstract: An image heating apparatus includes a coil for generating a magnetic flux by a current flowing therethrough; an image heating member having an electroconductive layer in which an eddy current is produced by the magnetic flux by which heat is generated, the image heating member being effective to heat an image on a recording material; an electroconductive magnetic flux adjusting member movable from a first position and a second position to decrease the eddy current produced in the image heating member by the magnetic flux; a temperature sensor for sensing a temperature of image heating member; electric power control means for control electric power supplied to the coil on the basis of an output of the temperature sensor, wherein the electric power control means changes an electric power condition to be supplied to the coil before start of the movement from the first position to the second position of magnetic flux adjusting member.

Abstract: An image forming apparatus capable of performing accurate gradation correction in a range of density where measurement by a toner density detection unit is impossible. A printer unit forms a gradation pattern on an image bearing member. A density detection sensor detects density of the gradation pattern. A first correction value for correcting gradation of the image data is calculated based on density of the gradation pattern, detected by the density detection sensor, and a second correction value for correcting gradation of the image data is calculated based on the estimated condition of toner with which a toner image is formed on the image bearing member. An output gamma correction unit corrects density in a low density range of the toner image based on the first correction value, and corrects density in a high density range of the toner image based on the second correction value.

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.