Abstract: An ultrasound treatment tool that includes: a probe that includes a main body and a treating portion; and a first tubular portion. The first tubular portion includes at least one through hole that is formed in a wall of the first tubular portion so as to be in fluid communication with a liquid channel in the first tubular portion, and an opening that is formed at a distal end of the first tubular portion. A total opening area of the through hole(s) is larger than a cross-sectional opening area of the liquid channel at the opening.

Abstract: An image forming apparatus includes a drive device including a first drive transmission passage through which a driving force of a drive source is transmitted to a developer bearer via a first joint and a second drive transmission passage through which the driving force is transmitted to a rotary body via a second joint. The first drive transmission passage and the second drive transmission passage are defined such that one of a first drive transmission ratio to the first joint of the first drive transmission passage and a second drive transmission ratio to the second joint of the second drive transmission passage is an integral multiple of the other of the first drive transmission ratio from the drive source to the first joint of the first drive transmission passage and the second drive transmission ratio from the drive source to the second joint of the second drive transmission passage.

Abstract: An image forming apparatus includes a drive device including a first drive transmission passage through which a driving force of a drive source is transmitted to a developer bearer via a first joint and a second drive transmission passage through which the driving force is transmitted to a rotary body via a second joint. The first drive transmission passage and the second drive transmission passage are defined such that one of a first drive transmission ratio to the first joint of the first drive transmission passage and a second drive transmission ratio to the second joint of the second drive transmission passage is an integral multiple of the other of the first drive transmission ratio from the drive source to the first joint of the first drive transmission passage and the second drive transmission ratio from the drive source to the second joint of the second drive transmission passage.

Abstract: An image forming apparatus includes a drive device including a first drive transmission passage through which a driving force of a drive source is transmitted to a developer bearer via a first joint and a second drive transmission passage through which the driving force is transmitted to a rotary body via a second joint. The first drive transmission passage and the second drive transmission passage are defined such that one of a first drive transmission ratio to the first joint of the first drive transmission passage and a second drive transmission ratio to the second joint of the second drive transmission passage is an integral multiple of the other of the first drive transmission ratio from the drive source to the first joint of the first drive transmission passage and the second drive transmission ratio from the drive source to the second joint of the second drive transmission passage.

Abstract: A drive transmission device includes a rotation shaft, a drive transmitter attached to the rotation shaft to slide in an axial direction and including an engaging portion extending in the axial direction, and a coil spring to bias the drive transmitter to one side in the axial direction, and a shaft-side drive transmitter disposed on the rotation shaft. The coil spring includes a sparse portion and a dense portion. The shaft-side drive transmitter engages the engaging portion to prevent the drive transmitter from disengaging from the rotation shaft. The coil spring and the engaging portion satisfy C>A?B where A represents a length of the coil spring in a state in which the shaft-side drive transmitter retains the drive transmitter, B represents a compressed height of the coil spring, and C represents a length of the coil spring in the axial direction.

Abstract: A power transmission device includes coaxially a first rotary body including a first gear on a drive source side, a second rotary body including a second gear on a driven side, a third rotary body including a third gear movably held to transmit a driving force, and a guide member disposed at one of the first gear, the second gear, and the third gear to contact a first end surface of a gear tooth of another of the first gear, the second gear, and the third gear, serving as a mating gear, to guide the first end surface between teeth of the one of the first gear, the second gear, and the third gear. The guide member extends toward the mating gear and a tip of the guide member is placed at a distance from an end of the one of the gears in the axial direction.

Abstract: An image forming apparatus includes a drive device including a first drive transmission passage through which a driving force of a drive source is transmitted to a developer bearer via a first joint and a second drive transmission passage through which the driving force is transmitted to a rotary body via a second joint. The first drive transmission passage and the second drive transmission passage are defined such that one of a first drive transmission ratio to the first joint of the first drive transmission passage and a second drive transmission ratio to the second joint of the second drive transmission passage is an integral multiple of the other of the first drive transmission ratio from the drive source to the first joint of the first drive transmission passage and the second drive transmission ratio from the drive source to the second joint of the second drive transmission passage.

Abstract: A rotary drive device includes a drive motor and drive transmission portion, which transmits a rotational drive force of the motor to a driven rotor and includes three or more drive transmission members. A high stiffness member is attached to a low-stiffness drive transmission member, which is one, lower in stiffness, of two of the drive transmission members, to increase stiffness of the low-stiffness drive transmission member. The two form a drive transmission point corresponding to a resonant point of a lowest resonance frequency among frequencies at a plurality of resonance points in frequency response characteristics derived from rotation information. One drive transmission point, which is on either a drive-transmission input side or output side, other than the drive transmission point corresponding to the resonant point of the lowest resonance frequency, of the low-stiffness drive transmission member is configured to transmit the rotational drive force through the high stiffness member.

Abstract: A drive transmission device includes a rotation shaft, a drive transmitter attached to the rotation shaft to slide in an axial direction and including an engaging portion extending in the axial direction, and a coil spring to bias the drive transmitter to one side in the axial direction, and a shaft-side drive transmitter disposed on the rotation shaft. The coil spring includes a sparse portion and a dense portion. The shaft-side drive transmitter engages the engaging portion to prevent the drive transmitter from disengaging from the rotation shaft. The coil spring and the engaging portion satisfy C>A?B where A represents a length of the coil spring in a state in which the shaft-side drive transmitter retains the drive transmitter, B represents a compressed height of the coil spring, and C represents a length of the coil spring in the axial direction.

Abstract: A driving force transmission device that transmits a driving force to a rotation body includes a flange member provided in the rotation body, a through shaft that is connected to the flange member to transmit the driving force to the rotation body via the flange member, and an intermediate transmission member that is provided in the through shaft to transmit the driving force to the flange member from the through shaft.

Abstract: A rotary drive device includes a drive motor and drive transmission portion, which transmits a rotational drive force of the motor to a driven rotor and includes three or more drive transmission members. A high stiffness member is attached to a low-stiffness drive transmission member, which is one, lower in stiffness, of two of the drive transmission members, to increase stiffness of the low-stiffness drive transmission member. The two form a drive transmission point corresponding to a resonant point of a lowest resonance frequency among frequencies at a plurality of resonance points in frequency response characteristics derived from rotation information. One drive transmission point, which is on either a drive-transmission input side or output side, other than the drive transmission point corresponding to the resonant point of the lowest resonance frequency, of the low-stiffness drive transmission member is configured to transmit the rotational drive force through the high stiffness member.

Abstract: A driving force transmission device that transmits a driving force to a rotation body includes a flange member provided in the rotation body, a through shaft that is connected to the flange member to transmit the driving force to the rotation body via the flange member, and an intermediate transmission member that is provided in the through shaft to transmit the driving force to the flange member from the through shaft.

Abstract: A power transmission device includes coaxially a first rotary body including a first gear on a drive source side, a second rotary body including a second gear on a driven side, a third rotary body including a third gear movably held to transmit a driving force, and a guide member disposed at one of the first gear, the second gear, and the third gear to contact a first end surface of a gear tooth of another of the first gear, the second gear, and the third gear, serving as a mating gear, to guide the first end surface between teeth of the one of the first gear, the second gear, and the third gear. The guide member extends toward the mating gear and a tip of the guide member is placed at a distance from an end of the one of the gears in the axial direction.