Abstract: A liquid discharge head includes: multiple nozzles; multiple individual chambers respectively communicating with the multiple nozzles; a common chamber communicating with each of the multiple individual chambers; multiple fluid restrictors between each of the multiple individual chambers and the common chamber; and multiple actuators driven to cause a liquid in the multiple individual chambers to be discharged from the multiple nozzles, a meniscus formed at each of the multiple nozzles has a natural period of vibration different from each of: a resonant period of the common chamber; half of the resonant period of the common chamber; and a quarter of the resonant period of the common chamber.

Abstract: A liquid discharge head includes a nozzle to discharge a liquid, a pressure generation chamber facing the nozzle, a common liquid chamber to supply the liquid to the pressure generation chamber, a fluid restrictor communicating with the pressure generation chamber, and a guide channel communicating with the fluid restrictor and the common liquid chamber. The guide channel includes a first adjacent portion communicating with the fluid restrictor. The pressure generation chamber has a first resonance period, and the guide channel has a second resonance period different from the first resonance period.

Abstract: A liquid discharge head includes a nozzle to discharge a liquid, an individual chamber communicating with the nozzle, a supply channel communicating with the individual chamber to supply the liquid to the individual chamber, and a discharge channel communicating with the individual chamber to discharge the liquid in the individual chamber. A fluid resistance of the supply channel is greater than a fluid resistance of the discharge channel.

Abstract: A liquid circulating apparatus includes a circulation route configured to circulate liquid through a liquid ejecting head, the circulation route including: a supply-side tank leading to a supply port of the liquid ejecting head; and a discharge-side tank leading to a discharge port of the liquid ejecting head, wherein the liquid is circulated by setting pressure in the supply-side tank higher than pressure in the discharge-side tank, and a sum of the pressure in the supply-side tank and the pressure in the discharge-side tank is set smaller when initial filling for filling the circulation route with the liquid is performed than when the liquid is circulated.

Abstract: A liquid discharge head includes a nozzle to discharge a liquid, an individual chamber communicating with the nozzle, a supply channel communicating with the individual chamber to supply the liquid to the individual chamber, and a discharge channel communicating with the individual chamber to discharge the liquid in the individual chamber. A fluid resistance of the supply channel is greater than a fluid resistance of the discharge channel.

Abstract: A liquid discharge head includes a nozzle to discharge a liquid, an individual chamber communicating with the nozzle, a supply channel communicating with the individual chamber to supply the liquid to the individual chamber, and a discharge channel communicating with the individual chamber to discharge the liquid in the individual chamber. A fluid resistance of the supply channel is greater than a fluid resistance of the discharge channel.

Abstract: A liquid discharge head includes a plurality of nozzles to discharge a liquid, a plurality of individual chambers communicating with the plurality of nozzles, a plurality of discharge channels communicating with the plurality of individual chambers, a plurality of supply-side common chambers connected to the plurality of individual chambers, and a plurality of discharge-side common chambers connected to the plurality of discharge channels. The plurality of discharge-side common chamber has a same fluid resistance.

Abstract: An ink discharge device is provided including an ink, an ink discharge head, and a circulator. The ink discharge head includes a nozzle, an individual liquid chamber communicated with the nozzle, a flow-in channel, and a flow-out channel. The circulator circulates the ink by letting the ink flow into the individual liquid chamber via the flow-in channel and flow out from the individual liquid chamber via the flow-out channel. A flow rate of the circulated ink is 0.10 to 1.50 times a maximum dischargeable rate of the ink discharge head. A dynamic surface tension A of the ink at 25° C. is 34.0 mN/m or less when measured by a maximum bubble pressure method at a surface lifetime of 15 msec, and the dynamic surface tension A and a static surface tension B of the ink at 25° C. satisfy the following relation: 10.0(%)?[(A?B)/(A+B)]×100?19.0(%).

Abstract: A liquid discharge head includes a plurality of nozzles from which liquid is discharged, a plurality of individual-liquid-chambers communicating with the plurality of nozzles, respectively, a plurality of individual-drainage-channels communicating with the plurality of individual-liquid-chambers, respectively, a drainage-side common-liquid-chamber communicating with each of the plurality of individual-drainage-channels, a filter having filter holes and disposed between the plurality of individual-drainage-channels and the drainage-side common-liquid-chamber, and an intermediate-drainage-channel disposed between the filter and the plurality of individual-drainage-channels. The intermediate-drainage-channel faces the filter and communicates with two or more of the plurality of individual-drainage-channels.

Abstract: A liquid circulating apparatus includes a circulation route configured to circulate liquid through a liquid ejecting head, the circulation route including: a supply-side tank leading to a supply port of the liquid ejecting head; and a discharge-side tank leading to a discharge port of the liquid ejecting head, wherein the liquid is circulated by setting pressure in the supply-side tank higher than pressure in the discharge-side tank, and a sum of the pressure in the supply-side tank and the pressure in the discharge-side tank is set smaller when initial filling for filling the circulation route with the liquid is performed than when the liquid is circulated.

Abstract: A liquid discharge head includes a nozzle to discharge a liquid, an individual chamber communicating with the nozzle, a supply channel communicating with the individual chamber to supply the liquid to the individual chamber, and a discharge channel communicating with the individual chamber to discharge the liquid in the individual chamber. A fluid resistance of the supply channel is greater than a fluid resistance of the discharge channel.

Abstract: A liquid discharge head includes a plurality of nozzles to discharge a liquid, a plurality of individual chambers communicating with the plurality of nozzles, a plurality of discharge channels communicating with the plurality of individual chambers, a plurality of supply-side common chambers connected to the plurality of individual chambers, and a plurality of discharge-side common chambers connected to the plurality of discharge channels. The plurality of discharge-side common chamber has a same fluid resistance.

Abstract: A liquid discharge head includes a plurality of nozzles from which liquid is discharged, a plurality of individual-liquid-chambers communicating with the plurality of nozzles, respectively, a plurality of individual-drainage-channels communicating with the plurality of individual-liquid-chambers, respectively, a drainage-side common-liquid-chamber communicating with each of the plurality of individual-drainage-channels, a filter having filter holes and disposed between the plurality of individual-drainage-channels and the drainage-side common-liquid-chamber, and an intermediate-drainage-channel disposed between the filter and the plurality of individual-drainage-channels. The intermediate-drainage-channel faces the filter and communicates with two or more of the plurality of individual-drainage-channels.

Abstract: An ink discharge device is provided including an ink, an ink discharge head, and a circulator. The ink discharge head includes a nozzle, an individual liquid chamber communicated with the nozzle, a flow-in channel, and a flow-out channel. The circulator circulates the ink by letting the ink flow into the individual liquid chamber via the flow-in channel and flow out from the individual liquid chamber via the flow-out channel. A flow rate of the circulated ink is 0.10 to 1.50 times a maximum dischargeable rate of the ink discharge head. A dynamic surface tension A of the ink at 25° C. is 34.0 mN/m or less when measured by a maximum bubble pressure method at a surface lifetime of 15 msec, and the dynamic surface tension A and a static surface tension B of the ink at 25° C. satisfy the following relation: 10.0(%)?[(A?B)/(A+B)]×100?19.0(%).

Abstract: A liquid discharge head includes a channel plate. The channel plate includes a fluid restrictor, a channel, a first plate member, and a second plate member. The channel is disposed on at least one of an upstream side and a downstream side of the fluid restrictor in a direction of flow of liquid. The channel has a greater width than a width of the fluid restrictor in a direction perpendicular to the direction of flow of liquid in an in-plane direction. The first plate member has a through hole including at least one broad portion and a narrow portion. The narrow portion is the fluid restrictor. The second plate member includes at least one through hole constituting part of the channel with the broad portion. The through hole is disposed opposite an end of the narrow portion at which the narrow portion is connected to the broad portion.

Abstract: A liquid discharge head includes a channel plate. The channel plate includes a fluid restrictor, a channel, a first plate member, and a second plate member. The channel is disposed on at least one of an upstream side and a downstream side of the fluid restrictor in a direction of flow of liquid. The channel has a greater width than a width of the fluid restrictor in a direction perpendicular to the direction of flow of liquid in an in-plane direction. The first plate member has a through hole including at least one broad portion and a narrow portion. The narrow portion is the fluid restrictor. The second plate member includes at least one through hole constituting part of the channel with the broad portion. The through hole is disposed opposite an end of the narrow portion at which the narrow portion is connected to the broad portion.

Abstract: A developing device includes a developer bearer, a developer regulator, a casing including an opposing face to oppose the developer bearer upstream from a developing range in a direction of rotation of the developer bearer, and first, second, and third seals. The first seal includes a first end secured to the casing and a second end to contact a latent image bearer upstream from the developing range in a direction of rotation of the latent image bearer. The second seal includes a first end secured to the opposing face of the casing, and a second end to contact the first seal upstream from the developing range. The third seal includes a first end secured to the opposing face of the casing, and a second end to contact developer on the developer bearer between the developer regulator and the developing range in the direction of rotation of the developer bearer.

Abstract: A developing device to develop a latent image on a rotatable image bearer includes an upstream developing roller disposed opposite the image bearer at a first developing position, and a downstream developing roller disposed adjacent to and downstream from the upstream developing roller in a direction of rotation of the image bearer, disposed opposite the image bearer at a second developing position. Each of the upstream developing roller and the downstream developing roller has a most approachable surface that approaches closest to the image bearer and a most withdrawn surface that withdraws farthest from the image bearer. In a state in which a reference surface point of the image bearer is disposed opposite the most approachable surface of the upstream developing roller at the first developing position, the reference surface point opposes the most withdrawn surface of the downstream developing roller at the second developing position.

Abstract: An image forming apparatus includes a removable unit to be removably installed in the image forming apparatus, having a unit-side opening, a connectable device having an apparatus-side opening to be connected to the unit-side opening to send developer from one of the removable unit and the connectable device to the other, a receptacle disposed below the unit-side opening and the apparatus-side opening to receive and store developer dropping from above, and a drawer unit to be retractably drawn out from the image forming apparatus. The receptacle is united with the drawer unit to be drawn out from the image forming apparatus together with the drawer unit.

Abstract: A developing unit includes a developer bearer to bear developer on a surface thereof, first and second developer conveyors each having a spiral blade mounted on a rotary shaft thereof parallel to a rotary axis of the developer bearer to convey developer in opposite directions to each other. A developer drain hole is provided at a given height in a side wall of a second developer conveyance channel to face a communication opening across the second developer conveyor. The first developer conveyor rotates in a direction with its spiral blade rising between the rotary shaft of the first developer conveyor and the communication opening. Rotational phases of the first developer conveyor and the second developer conveyor are fixed and synchronized with each other to weaken momentum of developer flow generated by the first developer conveyor toward the developer drain hole via the second developer conveyor.