Abstract: In an image forming apparatus including multiple light emitting elements, upon receiving an instruction from a user to execute correction (first correction) of a phase shift due to a shift in the relative positions of an optical scanning apparatus and the photosensitive member, a CPU executes correction (second correction) of a phase shift due to temperature change in the image forming apparatus. Thereafter, the CPU performs image formation control such that a phase adjustment image is formed on a recording medium, and determines a phase adjustment value based on an adjustment value input by the user. The CPU sets the phase adjustment value in the optical scanning apparatus to correct the phase shift. Thus, when the first correction is to be executed, the CPU executes the second correction before executing the first correction.

Abstract: In an image forming apparatus including multiple light emitting elements, upon receiving an instruction from a user to execute correction (first correction) of a phase shift due to a shift in the relative positions of an optical scanning apparatus and the photosensitive member, a CPU executes correction (second correction) of a phase shift due to temperature change in the image forming apparatus. Thereafter, the CPU performs image formation control such that a phase adjustment image is formed on a recording medium, and determines a phase adjustment value based on an adjustment value input by the user. The CPU sets the phase adjustment value in the optical scanning apparatus to correct the phase shift. Thus, when the first correction is to be executed, the CPU executes the second correction before executing the first correction.

Abstract: A color image forming apparatus configured to form a combination toner pattern including a second toner image formed downstream in a conveying direction of an intermediate transfer belt on a first toner image and a third toner image formed upstream in the conveying direction of the intermediate transfer belt on the first toner image so that the second and the third toner images cover at least a portion of the first toner image.

Abstract: An image forming apparatus capable of ensuring a sufficient difference between amounts of light reflected from a base such as a transfer material and from a toner pattern in the detection of the toner pattern for registration correction control by a reflective optical sensor. The image forming apparatus includes a pattern generator for generating a toner pattern, a pattern detection sensor for detecting the toner pattern formed on the intermediate transfer belt, a pattern density decider for determining the density of the toner pattern that makes the amount of light received by the sensor in detection of the toner pattern equal to or less than a predetermined value.

Abstract: An image forming apparatus which is capable of improving the accuracy of detecting the amount of misregistration. A control unit controls a plurality of image forming units so as to form a color registration pattern on a image bearing member. A detection unit detects diffusely reflected light reflected on the image bearing member and the color registration pattern. The control unit compares a first output value output by the detection unit detecting the surface of the image bearing member with a second output value output by the detection unit detecting a low-reflectivity toner pattern formed on the image bearing member, and determines a density of the color registration pattern corresponding to the low-reflectivity toner pattern based on a result of the comparison.

Abstract: An image forming apparatus includes an air ejecting portion that ejects air toward a gap between the top end of a sheet having passed through a nip of the heating roller and a pressure roller, and the circumference of the heating roller. The air ejecting portion includes a plurality of air nozzles and a plurality of electromagnetic valves being respectively connected thereto and ejects air selectively from a plurality of air ejection positions arranged in the width direction perpendicular to the sheet conveying direction.

Abstract: A pattern detection sensor receives light diffused by a pattern image, and it is difficult for the pattern detection sensor to detect a low-reflectance black pattern. Considering this, a high-reflectance yellow pattern is formed as the background of the low-reflectance black pattern. Even the diffused light reception type pattern detection sensor can detect the black pattern. The yellow pattern formed as the background is also used as a yellow pattern for detecting a color misalignment amount with respect to a pattern of magenta working as a reference color. The consumption amount of yellow toner is reduced while maintaining the color misalignment correction precision.

Abstract: An image forming apparatus includes a pattern forming unit which forms a light amount adjustment pattern on an image carrier belt, a light amount control unit which controls the amount of light irradiating the image carrier belt and pattern, a detection sensor which detects reflected light amounts from the image carrier belt and pattern with respect to the irradiating light amount and stores the detection results in a storage unit, a calculation unit which calculates the correspondence between the irradiating light amount and the reflected light amounts from the image carrier belt and pattern on the basis of the detection results and stores the calculation results in the storage unit, and a light amount decision unit which decides, on the basis of the calculation results, a light amount at which the difference between the reflected light amounts from the image carrier belt and pattern exhibits a value set in advance.

Abstract: A color image forming apparatus configured to form a combination toner pattern including a second toner image formed downstream in a conveying direction of an intermediate transfer belt on a first toner image and a third toner image formed upstream in the conveying direction of the intermediate transfer belt on the first toner image so that the second and the third toner images cover at least a portion of the first toner image.

Abstract: A low density area is caused at a trailing edge of an image formed on a photosensitive drum. This low density area is less likely to be caused when the density of the image is higher and the humidity is lower. To prevent generation of such low density area, if a color misregistration detection toner pattern having a high density is formed, in a low humidity environment, an excessively large amount of toner is consumed unnecessarily. In response, the density of the color misregistration detection toner pattern is adjusted based on the humidity.

Abstract: An image forming apparatus includes a pattern forming unit which forms a light amount adjustment pattern on an image carrier belt, a light amount control unit which controls the amount of light irradiating the image carrier belt and pattern, a detection sensor which detects reflected light amounts from the image carrier belt and pattern with respect to the irradiating light amount and stores the detection results in a storage unit, a calculation unit which calculates the correspondence between the irradiating light amount and the reflected light amounts from the image carrier belt and pattern on the basis of the detection results and stores the calculation results in the storage unit, and a light amount decision unit which decides, on the basis of the calculation results, a light amount at which the difference between the reflected light amounts from the image carrier belt and pattern exhibits a value set in advance.

Abstract: An image forming apparatus includes a pattern forming unit which forms a light amount adjustment pattern on an image carrier belt, a light amount control unit which controls the amount of light irradiating the image carrier belt and pattern, a detection sensor which detects reflected light amounts from the image carrier belt and pattern with respect to the irradiating light amount and stores the detection results in a storage unit, a calculation unit which calculates the correspondence between the irradiating light amount and the reflected light amounts from the image carrier belt and pattern on the basis of the detection results and stores the calculation results in the storage unit, and a light amount decision unit which decides, on the basis of the calculation results, a light amount at which the difference between the reflected light amounts from the image carrier belt and pattern exhibits a value set in advance.

Abstract: The image forming apparatus prevents poor imaging caused by temperature decrease of the fixing rotating member due to ejected air and reduces cost and power consumption. When a sheet passes though the nip portion of the heat roller 202 and the pressure roller, the air ejecting portion 204 ejects air toward a gap between the top end of the passing sheet and the circumference of the heat roller 202. The air ejecting portion 204 includes a plurality of air nozzles 505a to 505d and a plurality of electromagnetic valves 504a to 504d being respectively connected thereto and ejects air selectively from a plurality of air ejection positions arranged in the width direction being perpendicular to the sheet conveying direction.

Abstract: An image forming apparatus includes a pattern forming unit which forms a light amount adjustment pattern on an image carrier belt, a light amount control unit which controls the amount of light irradiating the image carrier belt and pattern, a detection sensor which detects reflected light amounts from the image carrier belt and pattern with respect to the irradiating light amount and stores the detection results in a storage unit, a calculation unit which calculates the correspondence between the irradiating light amount and the reflected light amounts from the image carrier belt and pattern on the basis of the detection results and stores the calculation results in the storage unit, and a light amount decision unit which decides, on the basis of the calculation results, a light amount at which the difference between the reflected light amounts from the image carrier belt and pattern exhibits a value set in advance.

Abstract: An image forming apparatus includes a pattern forming unit which forms a light amount adjustment pattern on an image carrier belt, a light amount control unit which controls the amount of light irradiating the image carrier belt and pattern, a detection sensor which detects reflected light amounts from the image carrier belt and pattern with respect to the irradiating light amount and stores the detection results in a storage unit, a calculation unit which calculates the correspondence between the irradiating light amount and the reflected light amounts from the image carrier belt and pattern on the basis of the detection results and stores the calculation results in the storage unit, and a light amount decision unit which decides, on the basis of the calculation results, a light amount at which the difference between the reflected light amounts from the image carrier belt and pattern exhibits a value set in advance.

Abstract: An image forming apparatus performing development using light toner of a first color and dark toner of the first color includes a control unit configured to control tone in order to set gradation characteristics of an image developed with the light toner; a determination unit configured to determine whether the gradation characteristics of the light toner image are in a desirable state as a result of the tone control by the control unit; and a shift unit configured to shift an area where mixture of the light toner with the dark toner is started, the area corresponding to the desirable state, responsive to the determination unit determining that the gradation characteristics of the light toner image are not in the desirable state.

Abstract: An image forming apparatus capable of ensuring a sufficient difference between amounts of light reflected from a base such as a transfer material and from a toner pattern in the detection of the toner pattern for registration correction control by a reflective optical sensor. The image forming apparatus includes a pattern generator for generating a toner pattern, a pattern detection sensor for detecting the toner pattern formed on the intermediate transfer belt, a pattern density decider for determining the density of the toner pattern that makes the amount of light received by the sensor in detection of the toner pattern equal to or less than a predetermined value.

Abstract: An image forming apparatus includes a pattern forming unit which forms a light amount adjustment pattern on an image carrier belt, a light amount control unit which controls the amount of light irradiating the image carrier belt and pattern, a detection sensor which detects reflected light amounts from the image carrier belt and pattern with respect to the irradiating light amount and stores the detection results in a storage unit, a calculation unit which calculates the correspondence between the irradiating light amount and the reflected light amounts from the image carrier belt and pattern on the basis of the detection results and stores the calculation results in the storage unit, and a light amount decision unit which decides, on the basis of the calculation results, a light amount at which the difference between the reflected light amounts from the image carrier belt and pattern exhibits a value set in advance.

Abstract: An image forming apparatus includes a plurality of image forming stations each having an image carrier and forming an image on the image carrier; a mark detecting unit for detecting a plurality of registration correction marks formed on a recording medium by the plurality of image forming stations; a correction mechanism for correcting a position difference between images formed by the plurality of image forming stations in accordance with a detection result by the mark detecting unit; and a controller for independently controlling an image forming operation of each of the plurality of the image forming stations so that the image density of each of the registration correction marks formed by the plurality of image forming units has a different predetermined image density.

Abstract: An image forming apparatus has a fixing unit for heat fixing an unfixed image formed on a recording material at a nip, with the fixing unit having a rotary fixing member disposed for contacting with the recording material; a heating member for externally heating the rotary fixing member; and a control for stopping revolution of the rotary fixing member in association with a door opening in the image forming apparatus, wherein the heating unit is controlled in association with the door opening and the contact state of the heating member and fixing member.