Konica Minolta, Inc.

Konica Minolta Business Technologies, Inc.

Yuta Tachibana

Hiroyuki Yoshikawa

Daichi Suzuki

Yuji Kobayashi

Yasuhiro Koide

Hiroshi Yamaguchi

Yuhei Tatsumoto

Takaki Kato

Kazumichi Yoshida

Tomonobu Tamura

Katsuhide Sakai

Harumitsu Fujimori

Satoshi Teshima

Norihiko Nakano

Hiroyuki Watanabe

Kouei Cho

Katsunori Takahashi

Toru Kasamatsu

Yoshiyuki Toso

Yutaka Otsuka

Satoshi Miyajima

Akimasa Ishikawa

Teruhiko Fujikura

Makoto Shimazoe

Shoichi Tsuge

Kou Yamada

Provided is an image forming system capable of accurately detecting the resistance of a recording material. The image forming system includes an application roller that applies a voltage to a recording material on a conveyance path, and a controller that calculates the electric resistance of the recording material from a relationship between the voltage applied to the application roller and a current. The controller calculates the resistance of the recording material based on first profile information that is acquired by changing the applied voltage and corresponds to a change in the resistance of the application roller, and second profile information that is acquired by changing the applied voltage in a state where the recording material is sandwiched and corresponds to the change in the resistance of the application roller.

Image forming system, resistance detection device, resistance detection method, and program

A rotation detector includes a motor, a current detector and a hardware processor. The motor includes coils of two or more phases and a rotor. The current detector detects currents flowing in coils of at least two phases among the coils of two or more phases. The hardware processor estimates an initial position of the rotor based on current values of the currents detected by the current detector to start the motor, controls an energization pattern on the phases to rotate and start the motor based on the estimated initial position, and determines whether the rotor stops or is rotating before completing the estimation of the initial position.

Rotation detector and image forming apparatus

A motor controller estimates an initial position of a magnetic pole of a rotor of a brushless DC motor in an inductive sensing scheme. The motor controller controls a drive circuit to apply an AC voltage to a stator winding at a first energization angle, and subsequently to apply an AC voltage to the stator winding at a second energization angle before a residual current flowing through the stator winding returns to zero. At each energization angle, the motor controller corrects a peak value of a current in the stator winding based on the residual current detected immediately before a voltage is applied to the stator winding or at a time when voltage application to the stator winding is started. Based on the corrected peak value, the control circuit estimates the initial position of the magnetic pole of the rotor.

Motor controller and image forming apparatus

A control circuit of a motor control device estimates an initial magnetic pole position of a rotor using an inductive sensing scheme. When estimating the initial magnetic pole position, a drive circuit applies a voltage to a stator winding at each of L electrical angles (L&#x2265;5) while changing the L electrical angles. An absolute value of an electrical angle difference of the voltage applied to the stator winding between an i-th time (2&#x2264;i&#x2264;L) and an i&#x2212;1st time is 180&#x2212;360/L degrees or more and 180+360/L degrees or less. An absolute value of an electrical angle difference of the voltage applied to the stator winding between a 1st time for initial position estimation and a last time before starting initial position estimation is 180&#x2212;360/L degrees or more and 180+360/L degrees or less.

Motor control device, image forming apparatus, and method for estimating initial position of magnetic pole of rotor

In a motor control device that controls a sensorless-type motor, a controller estimates an initial magnetic pole position of a rotor of a motor by an inductive sensing scheme while sequentially setting a plurality of energization angles. At each of the set energization angles, the controller converts peak values of currents flowing through a plurality of phases of a stator winding into a first current component having an electrical angle that is equal to a corresponding one of the set energization angles and a second current component that is different in electrical angle by 90 degrees from the first current component, to correct the first current component based on the second current component. The controller estimates the initial magnetic pole position of the rotor based on the corrected first current component that is obtained at each of the set energization angles.

Motor control device, method of estimating initial position of magnetic pole of rotor, and image forming apparatus

In a motor control device in one embodiment, an initial position estimation unit estimates an initial position of a magnetic pole of a rotor of a motor in an inductive sensing scheme. At each of energization angles, the initial position estimation unit multiplies a &#x3b3;-axis current component I&#x3b3; corresponding to a peak value of a current flowing through a stator winding by each of a cosine value and a sine value of a correction angle obtained by correcting each of the energization angles. The initial position estimation unit estimates the initial position of the magnetic pole of the rotor based on a ratio between an integrated value of a multiplication result about the cosine value and an integrated value of a multiplication result about the sine value.

In a motor control device, when estimating an initial position of a magnetic pole of a rotor of a motor, a drive circuit continuously or intermittently applies a voltage to a stator winding at each of a plurality of energization angles while sequentially changing the energization angles, and at a voltage value and for an energization time period, the voltage value and the energization time period being set such that the rotor does not rotate. An initial position estimation unit calculates an estimated initial position of the magnetic pole of the rotor based on a phase angle of a trigonometric function curve that approximates a change of a &#x3b3;-axis current I&#x3b3; with respect to each of the energization angles. The trigonometric function curve has a cycle equal to one electrical cycle of the motor.

A control device of a permanent magnet synchronous motor that is a control device of a sensorless-type permanent magnet synchronous motor in which a rotor using a permanent magnet rotates by a rotating magnetic field caused by a current flowing in an armature includes: a driver that applies a voltage to the armature and drives the rotor; an initial position estimator that estimates an initial position which is a magnetic pole position of the rotor that is stopped; and a controller that controls the driver so as to apply a pulse train including a voltage pulse for searching the initial position for each of n angle positions dividing a search range of an electrical angle of 360 degrees to the armature, wherein the pulse train includes a first pulse and a second pulse.

Control device of permanent magnet synchronous motor and image forming device

A motor controller includes: a velocity calculation unit for obtaining an angle &#x3b8;(n), which shows a rotation position, and an angular velocity &#x3c9;(n) of a rotor at a time point n; a compensation amount calculation unit for calculating a compensation angle &#x394;&#x3b8; by which the rotor advances from the time point n to a (n+1)th control cycle (a control cycle starting from a time point n+1), based on an angular acceleration a(n) of the rotor, an angular velocity &#x3c9;(n) of the rotor at the time point n and a time length T of the control cycle; and a PWM inverter for controlling a voltage to be applied to a coil such that a rotating magnetic field based on a rotation position of the rotor advanced by the compensation angle &#x394;&#x3b8; from the rotation position of the rotor at the time point n is formed in the (n+1)th control cycle.

Motor controller, image forming apparatus and motor controlling method

A controller for a sensorless permanent magnet synchronous motor having a rotor using a permanent magnet, the rotor rotating by a rotating magnetic field caused by a current flowing through an armature is provided. The controller is configured to apply a pulse voltage for generating a magnetic field vector for searching for the initial position to each of search sections obtained by dividing a target range, narrow down a target range in such a manner that a search section in which a largest amount of current flows through the armature by application of the pulse voltage is selected as a subsequent target range, and repeat the application processing and the narrow-down processing to estimate the initial position.

Controller for permanent magnet synchronous motor, and control method for estimating initial position of rotor

A method for controlling a permanent magnet synchronous motor having a rotor using a permanent magnet, the rotor rotating by a rotating magnetic field caused by a current flowing through an armature is provided. The method includes: presuming, based on a target speed and an estimated speed that is an estimated value of a rotational speed of the rotor, whether or not a step-out occurs; correcting, when it is presumed that a step-out occurs, an estimated angle that is an estimated value of a position of magnetic poles of the rotor; and controlling, based on a post-correction estimated angle that is the estimated angle after the correction, a current flowing through the armature to cause the rotating magnetic field rotating at the target speed.

Controller for permanent magnet synchronous motor, control method, and image forming apparatus

A sheet feeder picking up and transporting sheets includes a transport unit transporting sheets along a sheet transport path one by one, a gap occurrence detection unit detecting, within a predetermined section of the sheet transport path, occurrence of a gap between sheets, and a controller controlling a timing of the transport of sheets according to a result of the detection. The gap occurrence detection unit includes a first detection unit and a second detection unit. The first detection unit is configured to detect light that is emitted toward the predetermined section, reaches a converging surface thereof across the predetermined section, and converged on a receiving element thereof. The second detection unit is configured to detect light reflected by a sheet passing through the predetermined section. The occurrence of the gap is detected based on outputs from the first detection unit and the second detection unit.

Sheet feeder, document reader, and image forming apparatus

A control method for a three-phase DC brushless motor including a rotor that includes a plurality of magnetic poles and that is rotatable, a stator that includes a plurality of magnetic field generation parts to generate a magnetic field to be a driving source of the rotor, and a sensor to detect a magnetic pole of the rotor which pole passes through a first position in the stator is provided, the method including: detecting in which the sensor detects a first magnetic pole of the rotor which pole passes through the first position; estimating, based on a result of the detection of the first magnetic pole, time until the first magnetic pole reaches a second position in the stator; and controlling the plurality of magnetic field generation parts in such a manner that a suitable magnetic field is generated when the first magnetic pole passes through the second position.

Control method for three-phase dc brush less motor, control device, and image forming device

A controller for a permanent magnet synchronous motor includes an estimating portion configured to determine an estimated value of a rotational speed of the rotor and an estimated value of a position of magnetic poles of the rotor based on a value of the current detected by the current detector and a parameter value indicating an interlinkage magnetic flux caused by the permanent magnet across the winding; a control unit configured to control the drive portion to cause the rotating magnetic field based on the estimated value of the rotational speed and the estimated value of the position of the magnetic poles; and a correction portion configured to correct the parameter value indicating the interlinkage magnetic flux based on correction information, the correction information being determined based on a temperature of the winding and a relationship between the temperature of the winding and a temperature of the permanent magnet.

Controller for permanent magnet synchronous motor, image forming apparatus, and control method

In a device for controlling a motor mounted on a system with different operation modes, a controller unit calculates an input value for the motor based on an output value of the motor and a target value depending on operation modes of the system, and instructs a driver circuit of the motor to apply the input value to the motor. An estimation unit estimates an amount of rise in temperature of the motor by applying the input value for the motor to a thermal model of the motor. A notification unit compares a value estimated by the estimation unit with a threshold value. When the estimated value exceeds the threshold value, the notification unit sends a request for change of operation mode to the system.

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Toyokawa, Japan

Yuta Tachibana