Abstract: An image recording apparatus includes a first pullout unit, a second pullout unit, and a first lock mechanism. The first unit is movable along a first axis between a first retracted position where the first unit is fully retracted in the apparatus, and a first exposed position where at least one side surface thereof is fully exposed to the front of the apparatus. The second unit is movable along a second axis, which is perpendicular to the first axis, between a second retracted position where the second unit is fully retracted in the first unit, and a second exposed position where the second unit is exposed to a side of the side surface of the first unit. The first lock mechanism prevents movement of the second unit from the second retracted position to the second exposed position when the first unit is not in the first exposed position.

Abstract: A belt unit is provided with an endless belt, a driving roller, and a pair of guide ribs. The driving roller is disposed on an inner peripheral surface side of the endless belt and drives the endless belt. The pair of guide ribs is placed on each opposite widthwise end of the inner peripheral surface of the endless belt and contacts both end faces of the driving roller, thus preventing meandering of the endless belt. Additionally, the driving roller is equipped with a low friction region at both opposite lengthwise ends in a predetermined width and the low friction region is configured to have a friction coefficient that is lower than a friction coefficient of a region adjacent to the low friction region.

Abstract: An image forming apparatus (100) is equipped with a plurality of photoreceptor drums (31A to 31D), an intermediate transfer belt (41), a separating and contacting mechanisms (20), a tension roller (44), a meandering correction mechanism, and a controller. The separating and contacting mechanism (20) displaces the intermediate transfer belt (41). The meandering correction mechanism increases and decreases a biasing force applied to each of the opposite end portions of the tension roller (44) according to the amount of movement of the intermediate transfer belt (41) in the axial direction (94) of the tension roller (44). The controller, during a non-image forming period, at a predetermined timing during rotation of the intermediate transfer belt (41), executes a belt displacement process in which the intermediate transfer belt (41) is displaced from a predetermined reference position and then returned to the reference position.

Abstract: An image recording apparatus includes a first pullout unit, a second pullout unit, and a first lock mechanism. The first unit is movable along a first axis between a first retracted position where the first unit is fully retracted in the apparatus, and a first exposed position where at least one side surface thereof is fully exposed to the front of the apparatus. The second unit is movable along a second axis, which is perpendicular to the first axis, between a second retracted position where the second unit is fully retracted in the first unit, and a second exposed position where the second unit is exposed to a side of the side surface of the first unit. The first lock mechanism prevents movement of the second unit from the second retracted position to the second exposed position when the first unit is not in the first exposed position.

Abstract: An image forming apparatus (100) is equipped with a plurality of photoreceptor drums (31A to 31D), an intermediate transfer belt (41), a separating and contacting mechanisms (20), a tension roller (44), a meandering correction mechanism, and a controller. The separating and contacting mechanism (20) displaces the intermediate transfer belt (41). The meandering correction mechanism increases and decreases a biasing force applied to each of the opposite end portions of the tension roller (44) according to the amount of movement of the intermediate transfer belt (41) in the axial direction (94) of the tension roller (44). The controller, during a non-image forming period, at a predetermined timing during rotation of the intermediate transfer belt (41), executes a belt displacement process in which the intermediate transfer belt (41) is displaced from a predetermined reference position and then returned to the reference position.

Abstract: An image forming apparatus determines the amount of cleaning toner that is supplied to each of an intermediate transfer belt 31 and a secondary transfer belt 42 based on the number of sheets that have been fed with the pick-up side of the sheet opposed to the intermediate transfer belt 31 and the number of sheets that have been fed with the pick-up side of the sheet opposed to the secondary transfer belt 42; integrally forms on the intermediate transfer belt 31 cleaning toner images that are supplied to each of the intermediate transfer belt 31 and the secondary transfer belt 42; and switches the application and the stop application of the transfer voltage for transferring the toner image from the intermediate transfer belt 31 to the secondary transfer roller 41 at a timing corresponding to the determined amount of toner.

Abstract: An image recording apparatus includes a first pullout unit, a second pullout unit, and a first lock mechanism. The first unit is movable along a first axis between a first retracted position where the first unit is fully retracted in the apparatus, and a first exposed position where at least one side surface thereof is fully exposed to the front of the apparatus. The second unit is movable along a second axis, which is perpendicular to the first axis, between a second retracted position where the second unit is fully retracted in the first unit, and a second exposed position where the second unit is exposed to a side of the side surface of the first unit. The first lock mechanism prevents movement of the second unit from the second retracted position to the second exposed position when the first unit is not in the first exposed position.

Abstract: A displacement mechanism for a secondary transfer unit (40) includes a first eccentric cam (71), a second eccentric cam (72) and a shaft member (73). The first eccentric cam (71) and the second eccentric cam (72) are in contact with either edge portion of the secondary transfer unit (40) in width direction of a primary transfer belt (31), and rotate in phase with each other. The shaft member (73) supports the first eccentric cam (71) and the second eccentric cam (72). The first eccentric cam (71) is configured in such a manner that any radius in a peripheral portion (711) is of magnitude not less than a radius at a segment of the second eccentric cam (72) that is in phase with a segment of the peripheral portion (711).

Abstract: A belt unit is provided with an endless belt, a driving roller, and a pair of guide ribs. The driving roller is disposed on an inner peripheral surface side of the endless belt and drives the endless belt. The pair of guide ribs is placed on each opposite widthwise end of the inner peripheral surface of the endless belt and contacts both end faces of the driving roller, thus preventing meandering of the endless belt. Additionally, the driving roller is equipped with a low friction region at both opposite lengthwise ends in a predetermined width and the low friction region is configured to have a friction coefficient that is lower than a friction coefficient of a region adjacent to the low friction region.

Abstract: An image forming apparatus includes a waste toner box, a base, a detection sensor, a counter and a controller. The waste toner box collects toner not transferred to a sheet but remaining on a surface of a photoreceptor. The base is for placing the waste toner box thereon, and a position of the base changes with a weight of the waste toner box placed thereon. The detection sensor detects the position of the base to detect an amount of toner in the waste toner box placed on the base. The counter counts the number of sheets with images formed thereon. The controller determines whether or not to continue image formation on a sheet on a basis of a signal from the detection sensor and the counter.

Abstract: A transfer device includes a plurality of primary transfer rollers, a second link member and a regulatory member. The regulatory member restrains the second link member from moving further than a predetermined position toward the second direction. The second link member causes the primary transfer rollers to be displaced as it moves. The second link member is split into a plurality of link arms of which overall length is variable within a predetermined range; and its joint portion includes an elastic member urging the plurality of link arms toward a direction to which the overall length gets longer in a state where the second link member is most separate from a cam shaft, and a first locking section and a second locking section engaging the plurality of link arms with one another for the overall length not to get longer beyond a maximum value.

Abstract: A belt unit is provided with an endless belt, a driving roller, and a pair of guide ribs. The driving roller is disposed on an inner peripheral surface side of the endless belt and drives the endless belt. The pair of guide ribs is placed on each opposite widthwise end of the inner peripheral surface of the endless belt and contacts both end faces of the driving roller, thus preventing meandering of the endless belt. Additionally, the driving roller is equipped with a low friction region at both opposite lengthwise ends in a predetermined width and the low friction region is configured to have a friction coefficient that is lower than a friction coefficient of a region adjacent to the low friction region.

Abstract: An image forming apparatus includes: an image bearing element that bears a toner image to be transferred to a sheet; an image forming portion that forms the toner image on the image bearing element; a cleaning element that cleans the surface of the image bearing element; a storage portion that stores a history of print coverage; a control portion that makes the image forming portion form a cleaning toner image to be supplied to the image bearing element at time of cleaning by the cleaning element; and a print coverage calculating portion that calculates the print coverage of the sheet. The control portion obtains an average value of the print coverage in a period from after a previous cleaning by the cleaning element until before a current cleaning, and determines an amount of toner for the cleaning toner image supplied to the image bearing element based on the average value.

Abstract: An image forming apparatus includes: a transfer portion that transfers a toner image from a first image forming element to a second image forming element when transfer voltage is applied; and a control portion, at time of cleaning the plurality of image forming elements, after integrally forming a cleaning toner image to be supplied to the first image forming element and the second image forming element on the surface of the photoreceptor along a revolving direction, that controls the application of the transfer voltage to the transfer portion to transfer the toner image in a manner such that the toner image is divided into at least four sections along the revolving direction, out of which at least two sections that are not adjacent to each other are transferred from the first image forming element to the second image forming element.

Abstract: A belt conveyor member includes an endless belt and a cleaning blade. The cleaning blade is configured to remove residual toner remaining on a surface of the endless belt which is processed into a smooth surface. The endless belt has a first region and a second region. The first region is a region in contact with the cleaning blade which is located outside a region for a recording sheet of a maximum usable width to pass therethrough. The second region is located outside the first region. A contact surface between the cleaning blade and the first region is in a rough condition free from intimate contact.

Abstract: An image forming apparatus is provided with an image bearing unit, an intermediate transfer unit, a primary transfer unit, a pre-transfer charger, and a control portion. The pre-transfer charger is located downstream of the primary transfer unit and upstream of the secondary transfer unit in a revolving direction, faces the outer peripheral surface of the intermediate transfer unit along a perpendicular direction perpendicular to the revolving direction, and charges the intermediate transfer unit when voltage is applied. The control portion, at time when determination is made as to the necessity of cleaning the pre-transfer charger, secondarily transfers a cleaning assessment toner image by switching between a state in which the voltage is applied to the pre-transfer charger and a state in which the voltage is not applied to the pre-transfer charger, the cleaning assessment toner image being in a uniform density.

Abstract: A secondary transfer unit stretches a transfer belt in an endless form over a driving roller, a driven roller, a transfer roller, an auxiliary roller, and a support roller therebetween. The transfer belt moves, by rotation of the driving roller, along a circulation path which passes through a transfer position. The transfer roller and the auxiliary roller press the transfer belt from the inner peripheral surface of the transfer belt toward an intermediate transfer belt in the transfer position. The transfer belt has an outer peripheral surface thereof which is pressed against the intermediate transfer belt and is roughened so that the surface roughness of the outer peripheral surface becomes 6 ?m to 10 ?m.

Abstract: A displacement mechanism for a secondary transfer unit (40) includes a first eccentric cam (71), a second eccentric cam (72) and a shaft member (73). The first eccentric cam (71) and the second eccentric cam (72) are in contact with either edge portion of the secondary transfer unit (40) in width direction of a primary transfer belt (31), and rotate in phase with each other. The shaft member (73) supports the first eccentric cam (71) and the second eccentric cam (72). The first eccentric cam (71) is configured in such a manner that any radius in a peripheral portion (711) is of magnitude not less than a radius at a segment of the second eccentric cam (72) that is in phase with a segment of the peripheral portion (711).

Abstract: A transfer device includes a transfer belt, a transfer roller and a tension roller over which the transfer belt is passed in a tensioned condition and which is made to be in an electrically floated state; it also includes a guide member that is installed in the vicinity of the tension roller. A control section, in transfer processing, controls a first switch so that the guide member is in a grounded state while controlling a second switch so that an electric current being caused to flow to the transfer roller becomes a first electric current; and in cleaning processing, controls the first switch so that the guide member is in an electrically floated state while controlling the second switch so that an electric current being caused to flow to the transfer roller becomes a second electric current.

Abstract: A transfer device includes a transfer belt, a plurality of rollers, and meandering preventive ribs. The plurality of rollers entrain the transfer belt thereabout. The meandering preventive ribs are provided at opposite widthwise ends of an inner peripheral surface of the transfer belt for preventing the transfer belt from meandering on the plurality of rollers. The plurality of rollers include at least one hollow roller having a central shaft and a plurality of internal ribs connecting the central shaft with an inner periphery of the hollow roller in a radial manner. The internal ribs are located so as not to come into contact with the meandering preventive ribs.