Abstract: An image forming apparatus performs a serviceman call detection mode during its idling time. In this time, a control portion controls upper and lower pressuring rollers to be clamped, controls a driving motor, and controls a change-over mechanism to switch a braking motor off. A torque detection portion detects a torque value Y of the driving motor at this time. The control portion then controls the upper and lower pressuring rollers to be clamped, controls the driving motor, and controls the change-over mechanism to switch the braking motor on. The torque detection portion detects a torque value Z of the driving motor at this time. The control portion subtracts the torque value Y from the torque value Z to calculate a difference value. The control portion determines that the breaking motor is broken down when the difference value does not exceed the threshold value.

Abstract: A fixing apparatus comprises a fixing nip width adjustment unit configured to adjust the fixing nip width of a fixing nip portion; a braking force generation motor configured to generate an effective braking force in the direction to hinder rotation of an upper pressure roller; and a control unit configured to perform restore control for rotating the upper pressure roller and a lower pressure roller by driving a drive motor and speed keeping control for keeping the rotational speed of the braking force generation motor no higher than a predetermined speed during the restore control in a non-fixing period in which the fixing nip width adjustment unit is controlled to decrease the fixing nip width smaller than in a fixing period and a braking force is applied to the fixing side member by the braking force generation motor.

Abstract: A fixing apparatus includes an upper pressure roller, a fixing belt, a lower pressure roller which cooperates with the upper pressure roller and the fixing belt for forming a fixing nip portion which holds and conveys a sheet with a toner image therebetween; a drive motor which rotates the lower pressure roller; a plurality of motors each of which is capable of generating a braking force in the direction to hinder rotation of the upper pressure roller and an assist force in the direction to assist rotation of the upper pressure roller; a torque generation unit which generate an effective braking force in the direction to hinder rotation of the fixing side member as a combination of the braking and assist forces; and a control unit which switches the motor used to generate the braking force among the plurality of motors in accordance with a predetermined condition.

Abstract: A paper feed apparatus is capable of correcting the skew of a sheet irrespective of a differential conveyance distance. The paper feed apparatus is provided with a first large volume paper feed apparatus 100A having a control unit 130 which performs first correction control to correct the skew of a sheet by controlling a first conveyance unit 110 and forming a loop of the sheet P before a paper stop rollers 110d, and also performs second correction control to correct the skew of a sheet by controlling a second conveyance unit 120 and forming a loop of the sheet before a paper stop rollers 110d. In this case, the control unit 130 controls the first conveyance unit 110 and the second conveyance unit 120 in order that the skew correcting ability of the second correction control becomes greater than the skew correcting ability of the first correction control.

Abstract: An image forming apparatus comprises a drive motor configured to rotate the lower pressure roller, a torque generation unit for generating a breaking force in the direction to hinder rotation of a fixing belt in order to adjust the differential speed between the surface speed of the fixing belt and the surface speed of the lower pressure roller 64, and a control unit for adjusting the breaking force generated by the torque generation unit. The control unit adjusts the breaking force generated by the torque generation unit to decrease if the rotational torque of the drive motor is larger than a predetermined target torque, and increase if the rotational torque of the drive motor is smaller than the predetermined target torque.

Abstract: An image forming apparatus acquires sheet information indicating paper weight or the like of a transported sheet of paper. The apparatus also has a control portion and shifts a reference position which has been previously set to a direction orthogonal to a transporting direction of the sheet of paper based on the paper weight or the like of the transported sheet of paper. A deviation sensor detects a deviation of the sheet of paper with regard to the shifted reference position along the direction orthogonal to the transporting direction of the sheet of paper. A sheet shift portion shifts the sheet of paper to the shifted reference position based on the deviation detected by the deviation sensor.

Abstract: When conveying an envelope, a posture of the envelope is corrected by hitting a closed portion of the envelope, which is opposite side of an opened portion of the envelope, against a nip portion between upper and lower rollers of the pre-registration rollers and the envelope is then conveyed with the envelope being nipped by the upper and lower rollers of the pre-registration rollers. The upper and lower rollers of the pre-registration rollers nip the envelope to remove air from the envelope. When setting an envelope mode to control a conveying speed of the envelope based on a coverage rate of an image to be formed on the envelope, the conveying speed of the envelope is controlled by adjusting a rotation speed of the registration rollers based on the coverage rate of the set envelope mode.

Abstract: A paper feed apparatus is capable of correcting the skew of a sheet irrespective of a differential conveyance distance. The paper feed apparatus is provided with a first Large volume paper feed apparatus 100A having a control unit 130 which performs first correction control to correct the skew of a sheet by controlling a first conveyance unit 110 and forming a loop of the sheet P before a paper stop rollers 110d, and also performs second correction control to correct the skew of a sheet by controlling a second conveyance unit 120 and forming a loop of the sheet before a paper stop rollers 110d. In this case, the control unit 130 controls the first conveyance unit 110 and the second conveyance unit 120 in order that the skew correcting ability of the second correction control becomes greater than the skew correcting ability of the first correction control.

Abstract: Disclosed is an image forming apparatus, which makes it possible to reduce the frequency of image defect occurrences to a level as lower as possible by detecting abnormalities generated with age on the photoreceptor member and/or in the cleaning section, so as to suppress an amount of spoiled paper sheets and material. The image forming apparatus includes: a light source that is disposed at a position located between a cleaning section and a charging section, to emit an inspection light, which is to be irradiated onto a photoreceptor member over a main-scanning direction thereof; a tight-contact type image sensor that has a line image sensor to receive the inspection light reflected from a surface of the photoreceptor member; and a control section to determine a status of a surface of the photoreceptor member, based on a result of analyzing the inspection light receive by the line image sensor.

Abstract: When conveying an envelope, a posture of the envelope is corrected by hitting a closed portion of the envelope, which is opposite side of an opened portion of the envelope, against a nip portion between upper and lower rollers of the pre-registration rollers and the envelope is then conveyed with the envelope being nipped by the upper and lower rollers of the pre-registration, rollers. The upper and lower rollers of the pre-registration rollers nip the envelope to remove air from the envelope. When setting an envelope mode to control a conveying speed of the envelope based on a coverage rate of an image to be formed on the envelope, the conveying speed of the envelope is controlled by adjusting a rotation speed of the registration rollers based on the coverage rate of the set envelope mode.

Abstract: An image forming apparatus contains a transporting unit for transporting a sheet of paper to an image forming section, a deviation detection sensor which detects a passing position of the transported sheets of paper end outputs passing data of the transported sheets of paper for every sheet of paper, a deviation calculation section which generates deviation storage data for evaluating a condition of a transporting section or a detection section by performing statistical processing on the passing data of the transported sheets of paper, and a discrimination section which discriminates between a case in which there is malfunction in the transporting section and a case in which there is malfunction in the detection section by comparing the deviation storage data with deviation characteristics data for discriminating between the malfunction in the transporting section and the malfunction in the detection section.

Abstract: An image forming apparatus acquires sheet information indicating paper weight or the like of a transported sheet of paper. The apparatus also has a control portion and shifts a reference position which has been previously set to a direction orthogonal to a transporting direction of the sheet of paper based on the paper weight or the like of the transported sheet of paper. A deviation sensor detects a deviation of the sheet of paper with regard to the shifted reference position along the direction orthogonal to the transporting direction of the sheet of paper. A sheet shift portion shifts the sheet of paper to the shifted reference position based on the deviation detected by the deviation sensor.

Abstract: Disclosed is an image forming apparatus, which makes it possible to reduce the frequency of image defect occurrences to a level as lower as possible by detecting abnormalities generated with age on the photoreceptor member and/or in the cleaning section, so as to suppress an amount of spoiled paper sheets and material. The image forming apparatus includes: a light source that is disposed at a position located between a cleaning section and a charging section, to emit an inspection light, which is to be irradiated onto a photoreceptor member over a main-scanning direction thereof; a tight-contact type image sensor that has a line image sensor to receive the inspection light reflected from a surface of the photoreceptor member; and a control section to determine a status of a surface of the photoreceptor member, based on a result of analyzing the inspection light receive by the line image sensor.

Abstract: Disclosed is an image forming apparatus to form an image on a paper, comprising: a main body section including a housing to house an apparatus to perform processing for the paper, and a control circuit to control the apparatus housed in the housing; and a peripheral apparatus provided separately from the main body section, which includes a hardware module having an electric component, and is connected to the control circuit so that communication therebetween is performed, and which is detachably provided to the housing, wherein a position at which the peripheral apparatus is provided to the housing can be changed, wherein the housing and the peripheral apparatus respectively include a conductive material, and the conductive material of the housing is grounded, and wherein when the peripheral apparatus is provided to the housing, the conductive material of the housing is conductive with the conductive material of the peripheral apparatus.

Abstract: In an image forming apparatus for forming a color image by superposing component color images, a control device obtains position data representing a forming position of each of plural registration mark images for the component color images with respect to a positional reference value arbitrarily determined, divides the position data into each of a unit reference range representing a range in which one mark image is formed, converts the position data divided for each unit reference range into those based on respective reference values representing the front edge of the unit reference ranges, extracts the position data representing ranges common to the mutually overlapping ranges each of which is represented by a couple of position data corresponding to the rising and falling edges of a passage timing pulse as read position data of the mark image of the component color, and calculates the amounts of positional deviations of the component color images from one another on the basis of the position data extracted.

Abstract: In an image forming apparatus for forming a color image by superposing component color images, a control device obtains position data representing a forming position of each of plural registration mark images for the component color images with respect to a positional reference value arbitrarily determined, divides the position data into each of a unit reference range representing a range in which one mark image is formed, converts the position data divided for each unit reference range into those based on respective reference values representing the front edge of the unit reference ranges, extracts the position data representing ranges common to the mutually overlapping ranges each of which is represented by a couple of position data corresponding to the rising and falling edges of a passage timing pulse as read position data of the mark image of the component color, and calculates the amounts of positional deviations of the component color images from one another on the basis of the position data extracted.

Abstract: An image printing apparatus includes a control unit which controls a rotational speed of an image carrier; a detecting unit which detects data of the rotational speed; a storage unit which stores the rotational speeds up to n past rotation cycle of said image carrier; and a determining unit which determines whether a rotational speed difference between a latest rotational speed in a current rotation cycle and a rotational speed in n past rotation cycle before the current rotation cycle at a predetermined interval, which includes the same rotational position in respective rotation cycles and its near position, is more than a predetermined reference value, wherein said control unit controls the rotational speed of said image carrier by using the data of rotational speeds at a predetermined interval including the same rotational position in one or n past rotation cycle before the current rotation cycle, and further said control unit controls a rotational speed in a subsequent rotation cycle next to the current r

Abstract: An image forming apparatus for forming color images may include at least two or more colors, having a function of magnification correction of image size by one page unit, the image forming apparatus including: an image carrier; a polygonal mirror rotator independently provided for each color; and a controller which simultaneously conducts first control for changing rotation speed of the polygonal mirror rotator in order for changing image size in a sub-scanning direction perpendicular to a main scanning direction, and second control for correcting a correction amount for color registration error depending on magnification correction of image size, and for adjusting a rotating phase of the polygonal mirror rotator depending on the corrected correction amount for color registration error.

Abstract: In an image forming apparatus for forming a color image by superposing component color images, a control device obtains position data representing a forming position of each of plural registration mark images for the component color images with respect to a positional reference value arbitrarily determined, divides the position data into each of a unit reference range representing a range in which one mark image is formed, converts the position data divided for each unit reference range into those based on respective reference values representing the front edge of the unit reference ranges, extracts the position data representing ranges common to the mutually overlapping ranges each of which is representing by a couple of position data corresponding to the rising and falling edges of a passage timing pulse as read position data of the mark image of the component color, and calculates the amounts of positional deviations of the component color images from one another on the basis of the position data extracted

Abstract: An image forming apparatus for forming the image based on the image information on the prescribed surface of the transfer material, having an image forming section 8 to form benchmarks for image position identification at prescribed positions on the sheet, benchmark sensors 11 and 12 to detect the position of the benchmarks formed on the sheet and to output position information, a memory section 30 to memorize the position information detected by the mark sensors 11 and 12, and a control section 15 to carry out statistical processing of the position information memorized in the memory section 30 so as to understand tendency and characteristic of displacement amounts of the benchmarks analyzed quantitatively with time.