Abstract: A power transmission device includes an armature that is shaped into a circular ring form. The armature is configured to be coupled with a rotor by an electromagnetic attractive force of an electromagnet at a time of energizing the electromagnet and is configured to be decoupled from the rotor at a time of deenergizing the electromagnet. The armature has an armature-side friction surface that is configured to contact a rotor-side friction surface of the rotor at the time of energizing the electromagnet. The armature-side friction surface has a plurality of grooves, each of which extends from a radially inner end portion of the armature-side friction surface to a location that is on a radially inner side of a radially outer end portion of the armature-side friction surface.

Abstract: A characteristic detector includes two electrodes facing each other to form a passage through which a medium passes, a cover disposed between the two electrodes, a current generator to supply a current between the two electrodes, a capacitance gauge to measure a capacitance generated between the two electrodes, and circuitry. The two electrodes have a shape or an arrangement in which at least two points on a leading end of the medium enter the passage with a time lag. The cover covers one of the two electrodes in connection with a size of the medium. The capacitance gauge detects the size of the medium based on the measured capacitance. The circuitry calculates a characteristic of the medium based on the capacitance measured by the capacitance gauge and the size of the medium detected by the capacitance gauge.

Abstract: A water content measuring device measures water content of an object to be measured. The water content measuring device includes two plate members that are disposed facing each other, a current generating unit, a measuring unit, and an arithmetic processing unit. The current generating unit generates current supplied between the two plate members. The measuring unit measures electrostatic capacitance generated by the current supplied between the two plate members. The arithmetic processing unit is configured to convert the electrostatic capacitance measured by the measuring unit to water content. Two plate members each have a shape or are disposed such that at least two points on a leading edge of the object enter between the two plate members at different timings in a direction perpendicular to a passing direction in which the object passes through the two plate members.

Abstract: A powder-amount detection device includes a first electrode, a second electrode, a third electrode and a voltage detector with the second electrode adjacent to the first electrode on the powder container and have a smaller surface area than a surface area of the first electrode. The third electrode is on a side opposite to the second electrode with the powder container interposed between the third electrode and each of the first electrode and the second electrode. The voltage detector detects voltages of the first electrode and the second electrode by detecting charging and discharging behaviors of the first electrode and the second electrode when a voltage is applied between the third electrode and each of the first electrode and the second electrode for a short time, and detects the amount of powder in the powder container based on the voltages of the first electrode and the second electrode.

Abstract: A thickness detector includes a rotator having different shape marks, disposed at different positions in a rotation direction; an opposing member disposed opposite the rotator; a detector to detect and output a displacement amount of the rotator or the opposing member in a sheet thickness direction; and a controller. The controller is configured to acquire first output values for one rotation from the detector, in a state without sheet; determine, based on a value output from the detector, whether one of the plurality of marks is detected in a state with the sheet held; acquire a predetermined number of second output values after one of the marks is detected; extract, from the first output values, values corresponding to the second output values, based on the value corresponding to the detected mark; and calculate a sheet thickness based on the second output values and the extracted first output values.

Abstract: A remaining powder amount detection device includes: a powder moving portion configured to change a distribution of powder in an inner space of a powder container containing the powder; a drive unit configured to drive the powder moving portion; a change value detector configured to detect a change value indicating a positional change of the powder container; and a remaining powder amount detector configured to detect a remaining amount of the powder contained in the powder container, based on the change value. The drive unit is configured to drive the powder moving portion so as to move the powder to near the change value detector. The remaining powder amount detector is configured to detect the remaining amount based on the change value in a state where the powder is moved to near the change value detector.

Abstract: A powder-amount detection device includes an outer electrode, an inner electrode, and a detector. The outer electrode is disposed outside a powder container to be replaceably installed to an image forming apparatus. The inner electrode is disposed inside a powder supply port of the powder container. The detector is configured to apply an electric field between the outer electrode and the inner electrode to detect a capacitance between the outer electrode and the inner electrode.

Abstract: A power transmission device includes an armature that is shaped into a circular ring form and is configured to be coupled with a rotor by an electromagnetic attractive force of an electromagnet at a time of energizing the electromagnet and is configured to be decoupled from the rotor at a time of deenergizing the electromagnet. The armature has an armature-side friction surface that is configured to contact a rotor-side friction surface of the rotor at the time of energizing the electromagnet. Grooves are formed at the armature-side friction surface such that each of the grooves extends in a form of slit from a radially inner side toward a radially outer side of the armature-side friction surface. A different type of material, which is different from a material of the armature-side friction surface, is placed in the grooves.

Abstract: A power transmission device includes an armature that is shaped into a circular ring form. The armature is configured to be coupled with a rotor by an electromagnetic attractive force of an electromagnet at a time of energizing the electromagnet and is configured to be decoupled from the rotor at a time of deenergizing the electromagnet. The armature has an armature-side friction surface that is configured to contact a rotor-side friction surface of the rotor at the time of energizing the electromagnet. The armature-side friction surface has a plurality of grooves, each of which extends from a radially inner end portion of the armature-side friction surface to a location that is on a radially inner side of a radially outer end portion of the armature-side friction surface.

Abstract: A characteristic detector includes two electrodes facing each other to form a passage through which a medium passes, a cover disposed between the two electrodes, a current generator to supply a current between the two electrodes, a capacitance gauge to measure a capacitance generated between the two electrodes, and circuitry. The two electrodes have a shape or an arrangement in which at least two points on a leading end of the medium enter the passage with a time lag. The cover covers one of the two electrodes in connection with a size of the medium. The capacitance gauge detects the size of the medium based on the measured capacitance. The circuitry calculates a characteristic of the medium based on the capacitance measured by the capacitance gauge and the size of the medium detected by the capacitance gauge.

Abstract: A powder-amount detection device includes an outer electrode, an inner electrode, and a detector. The outer electrode is disposed outside a powder container to be replaceably installed to an image forming apparatus. The inner electrode is disposed inside a powder supply port of the powder container. The detector is configured to apply an electric field between the outer electrode and the inner electrode to detect a capacitance between the outer electrode and the inner electrode.

Abstract: A remaining powder amount detection device includes: a powder moving portion configured to change a distribution of powder in an inner space of a powder container containing the powder; a drive unit configured to drive the powder moving portion; a change value detector configured to detect a change value indicating a positional change of the powder container; and a remaining powder amount detector configured to detect a remaining amount of the powder contained in the powder container, based on the change value. The drive unit is configured to drive the powder moving portion so as to move the powder to near the change value detector. The remaining powder amount detector is configured to detect the remaining amount based on the change value in a state where the powder is moved to near the change value detector.

Abstract: A powder-amount detection device includes a first electrode disposed on one side of a powder container to be replaceably installed to an image forming apparatus; a second electrode disposed adjacent to the first electrode and having a smaller surface area than the first electrode, an influence of an amount of powder in the powder container to a capacitance of the second electrode being as small as negligible; a third electrode disposed on a side opposite to the second electrode with the powder container interposed between the third electrode and each of the first electrode and the second electrode; and a voltage detector configured to detect charging and discharging behaviors of the first electrode and the second electrode when a voltage is applied between the third electrode and each of the first electrode and the second electrode for a short time, to detect the amount of powder in the powder container.

Abstract: A water content measuring device measures water content of an object to be measured. The water content measuring device includes two plate members that are disposed facing each other, a current generating unit, a measuring unit, and an arithmetic processing unit. The current generating unit generates current supplied between the two plate members. The measuring unit measures electrostatic capacitance generated by the current supplied between the two plate members. The arithmetic processing unit is configured to convert the electrostatic capacitance measured by the measuring unit to water content. Two plate members each have a shape or are disposed such that at least two points on a leading edge of the object enter between the two plate members at different timings in a direction perpendicular to a passing direction in which the object passes through the two plate members.

Abstract: A thickness detector includes a rotator having different shape marks, disposed at different positions in a rotation direction; an opposing member disposed opposite the rotator; a detector to detect and output a displacement amount of the rotator or the opposing member in a sheet thickness direction; and a controller. The controller is configured to acquire first output values for one rotation from the detector, in a state without sheet; determine, based on a value output from the detector, whether one of the plurality of marks is detected in a state with the sheet held; acquire a predetermined number of second output values after one of the marks is detected; extract, from the first output values, values corresponding to the second output values, based on the value corresponding to the detected mark; and calculate a sheet thickness based on the second output values and the extracted first output values.