Abstract: A DLL circuit includes a delay line (CDL) (10) that delays a clock signal at a relatively coarse adjustment pitch, a delay line (FDL) (20) that delays the clock signal at a relatively fine adjustment pitch, and phase detecting circuits and counter control circuits that control delay amounts of the delay lines (10, 20). The counter control circuits control the delay line (10) by a linear search method, and control the delay line (20) by a binary search method. As a result, even when the number of bits of the count signal for adjusting the delay line (20) is increased, a delay amount can be determined at a high speed.

Abstract: A fixing apparatus that firmly adheres unfixed toner onto a recording sheet includes a first cleaning unit for cleaning up toner adhering to a surface of a heating roller by using a belt-shaped cleaning member, and a second cleaning unit for cleaning up toner adhering to a surface of a pressurizing roller by using a roller-shaped member, wherein oil for promoting releasability is not supplied from the first cleaning unit whose cleaning member is an oilless member to the heating roller, and the oil is supplied only from the roller-shaped member of the second cleaning unit to the pressurizing roller.

Abstract: A duty detection circuit includes discharge transistors, charge transistors, detection lines, and a comparator circuit that detects a potential difference of these detection lines, and also includes a gate circuit that controls the discharge transistors and the charge transistors in response to the internal clock signal of an even cycle. As a result, the detection lines are charged and discharged in response to the internal clock signal of the even cycle. Consequently, the duty detection circuit can be applied to a multi-phase DLL circuit, and a potential difference appearing in the detection line can be sufficiently secured.

Abstract: A movable sheet stacking device including: a sheet receiving section which is provided with respect to a sheet exit section of an image forming apparatus and is for receiving ejected sheets being ejected from the sheet exit section in an ejecting direction and moving the sheets in a direction opposite to the ejecting direction; an end-portion restriction plate which comes into contact with a front end of the sheets moving in the opposite direction to stop the movement of the sheets; and a restriction-plate driving section which sets a position of the end-portion restriction plate according to a sheet type.

Abstract: A sheet feeding device is adapted to feed a sheet to a sheet processing apparatus. The sheet feeding device has a stacking plate, a first guiding member, and an angle adjustment mechanism. The stacking plate is adapted for sheets to be stacked thereon. The first guiding member is adapted to move on the stacking plate along a width dimension thereof perpendicular to a sheet feeding direction. The first guiding member is also adapted to rotate around a vertical axis. The first guiding member has a vertical guiding surface for positioning the sheets disposed on the stacking plate. The angle adjustment mechanism is adapted to rotate the guiding member around the vertical axis, for slanting the guiding member with the vertical guiding surface at an angle with the sheet feeding direction.

Abstract: A paper press member 240 configured to be capable of advancing and retracting with respect to a paper guide 220 is provided between a paper feed roller 234 and the front end in the paper feed direction of paper loaded in a manual feed tray 230. When a plurality of sheets of paper enter into the press-contact section between the paper feed roller 234 and a reverse roller 235, the reverse roller 235 is rotated in the reverse direction to retract the sheet on the reverse roller side to the manual feed tray 230. At this time, by causing the paper press member 240 to project from the upper surface of the paper guide 220, the sheet to be retracted and the paper press member 240 come into contact with each other, so that the travel amount of the sheet when retracting the sheet is reduced.

Abstract: A sheet feeder has a feed passage and includes feed roller pairs, sensors, and a controller. The feed roller pairs are arranged along the feed passage and feed sheets of paper in a feed direction along the passage by nipping the sheets. Each of the sensors is fitted at or near one of the feed roller pairs and senses a specified point on each of the sheets when the sheet is nipped by at least the associated roller pair. The controller includes a memory for storing reference feed timings as proper feed timings at each of which the specified points on the sheets should pass one of the sensors. The controller finds the real feed timing when each of the sensors senses the specified point on the sheet nipped by at least the associated roller pair.

Abstract: In one embodiment, a predetermined period different from a fixing process period in which fixing of toner to recording paper is carried out is set as a toner removal period, and during the toner removal period a hot roller and a pressure roller are intermittently rotated, and separation claws in contact with the rollers are caused to vibrate by the intermittent rotation of the rollers such that toner adhered to the separation claws is caused to drop due to this and is removed. Also, faces of the separation claws that oppose the surfaces of the hot roller and the pressure roller are set in a convex shape.

Abstract: A phase comparing circuit includes a first storage circuit for reading an external clock signal based on a control clock signal; first and second inverters for inverting a signal from the first storage circuit based respectively on first and second threshold levels; third and fourth inverters for inverting respective signals output from the first and second inverters; a delay circuit for delaying the control clock signal by a specific time; a coincidence control circuit for setting the delayed control clock signal to be active when the signals from the third and fourth inverters coincide with each other, and setting it to be inactive when the signals from the third and fourth inverters do not coincide with each other; and a second storage circuit for reading a signal output form the first storage circuit when the delayed control clock signal is active, and outputting the read signal as the control signal.

Abstract: The purpose is to provide a control method of driving toner containers for use in an apparatus including a plurality of toner containers each filled with toner and detachably mounted thereinto from a toner container covering structure; and a toner supply device for supplying toner to a developing unit while rotating the plurality of toner container. This method includes the step of detecting a first toner container whose toner has run out, among the plurality of toner containers. When the first toner container has been detected, this method makes a control including the steps of: opening the toner container covering structure; stopping the rotational motion of the first toner container; and continuing the rotational motion of a second toner container or containers other than the first toner container.

Abstract: A feeding device according to the present invention includes a box, paper holders, and a shifting mechanism. The box is open at Its top. The paper holders are open at their tops and positioned in the box. Each of the paper holders holds a pile of sheets of paper in it. The shifting mechanism so shifts at least one of the paper holders that the top sheet in one of the paper holders is positioned in a single freed position in the box according to selection data output from the apparatus with which the feeding device is used.

Abstract: A voltage controlled oscillator that is a differential ring oscillator type voltage controlled oscillator that, by connecting in cascade differential delay elements to which differential clock signals of a mutually reverse phase are input and controlling the current that flows to the differential delay elements by a bias voltage, controls a delay amount of this differential clock signal, having a phase detection portion that outputs a detection signal by comparing an output voltage of the differential output of any differential delay element and a reference voltage that is set to a voltage that detects an abnormal operation, and a cross-coupled circuit that is provided at each of the differential delay elements and, when the detection signal is input, amplifies the potential difference between the pair of differential output terminals.

Abstract: A transport path switching unit is provided between transport rollers and pre-registration rollers, and control is performed to switch between a main transport path and an extended transport path of the transport path switching unit such that either the main transport path or the extended transport path is interposed as the part of the paper transport path between the transport rollers and the pre-registration rollers to vary a total length of the paper transport path.

Abstract: A developer collecting apparatus for collecting waste developer which is generated by cleaning residual developer remained on a photoreceptor and an intermediate transfer body, includes: a waste developer container for accommodating the waste developer; a stirring member rotatably provided in the waste developer container, for stirring the waste developer; and a driving section for giving a rotary driving force to the stirring member. The driving section of the stirring member has: a driving source; a first driving force transmitting path and a second driving force transmitting path which are coupled on the driving source, for transmitting the rotary driving force to the stirring member, and when a rotational load on the first driving force transmitting path reaches a predetermined level or more, a switch-over of transmitting path can be performed from the first driving force transmitting path to the second driving force transmitting path.

Abstract: A delay circuit includes a first delay line circuit having a plurality of stages of delay units, a second delay line circuit having a plurality of stages of delay units, a plurality of transfer circuits provided in association with respective stages of the delay units of the first delay line circuit, the transfer circuits controlling the transfer of the outputs of the delay units of the first delay line circuit to associated stages of the delay units of the second delay line circuit. The delay units of respective stages of the first delay line circuit inverting input signals. Each stage delay unit of the second delay line circuit includes a logic circuit receiving an output signal of the transfer circuit associated with the delay unit in question and an output signal of a preceding stage to send an output signal to a following stage. The duty ratio is rendered variable by independently selecting the rising edge of the input signal and a propagation path of the falling edge.

Abstract: One embodiment of the present invention involves a roller drive control method for a fixing apparatus in which a separation claw for separating a recording paper and a cleaning unit for removing toner that has become residual on a surface of a heat roller are arranged near a surface of the heat roller that fixes toner onto the recording paper, wherein a predetermined period different from a fixing process period in which fixing of toner onto the recording paper is carried out is set as a toner removal period for removing toner that has adhered to the separation claw, and the heat roller is rotationally driven so that the rotation velocity of the heat roller is different in the fixing process period and the toner removal period.

Abstract: A delay circuit includes a first delay line circuit having a plurality of stages of delay units, a second delay line circuit having a plurality of stages of delay units, a plurality of transfer circuits provided in association with respective stages of the delay units of the first delay line circuit, the transfer circuits controlling the transfer of the outputs of the delay units of the first delay line circuit to associated stages of the delay units of the second delay line circuit. The delay units of respective stages of the first delay line circuit inverting input signals. Each stage delay unit of the second delay line circuit includes a logic circuit receiving an output signal of the transfer circuit associated with the delay unit in question and an output signal of a preceding stage to send an output signal to a following stage. The duty ratio is rendered variable by independently selecting the rising edge of the input signal and a propagation path of the falling edge.

Abstract: A delay circuit includes a first delay line circuit having a plurality of stages of delay units, a second delay line circuit having a plurality of stages of delay units, a plurality of transfer circuits provided in association with respective stages of the delay units of the first delay line circuit, the transfer circuits controlling the transfer of the outputs of the delay units of the first delay line circuit to associated stages of the delay units of the second delay line circuit. The delay units of respective stages of the first delay line circuit inverting input signals. Each stage delay unit of the second delay line circuit includes a logic circuit receiving an output signal of the transfer circuit associated with the delay unit in question and an output signal of a preceding stage to send an output signal to a following stage. The duty ratio is rendered variable by independently selecting the rising edge of the input signal and a propagation path of the falling edge.

Abstract: A paper feeder comprises an acquiring device, a driving roller, driven rollers, a driven roller supporter, a driver, and a controller. The acquiring device acquires thickness information on a sheet of paper. The driving roller rotates by being supplied with torque. The driven rollers rotate with the driving roller when in compressive contact with the driving roller. The driven roller supporter so supports the driven rollers that each of them can rotate under a different rotational load. The driver changes the position of the driven roller supporter relative to the driving roller. The controller selects one of the driven rollers on the basis of the thickness information and so activates the driver as to bring the selected roller into compressive contact with the driving roller.

Abstract: In one embodiment of the invention, in an image forming apparatus that reverses the front and back of recording paper by performing switchback transport of the recording paper to perform duplex printing of the recording paper, the image forming apparatus is provided with a control means that, when performing duplex printing of the recording paper, forms a void area at a leading end and a trailing end of the recording paper, the void area preventing curling of the recording paper around a roller.