US-12617213-B2 - Liquid supply apparatus and liquid application apparatus

US12617213B2US 12617213 B2US12617213 B2US 12617213B2US-12617213-B2

Abstract

A liquid supply apparatus includes a compressed air supply source, a pressurizing tank, a feeder, a discharge head, a mitigation device, and a circulation path. The compressed air supply source compresses air. The feeder feeds liquid accumulated in the pressurizing tank to a liquid flow path. The discharge head includes an internal flow path through which the liquid fed from the liquid flow path flows. The discharge head has a nozzle to discharge the liquid from the internal flow path. The mitigation device is installed on the liquid flow path at a position downstream from the pressurizing tank and upstream from the discharge head, and absorbs a fluctuation in pressure of the liquid flowing through the liquid flow path. In the circulation path, the feeder circulates the liquid in the liquid flow path in an order of the pressurizing tank, the mitigation device, the discharge head, and the pressurizing tank.

Inventors

Tomofumi Yoshida

Assignees

Tomofumi Yoshida

Dates

Publication Date: 20260505
Application Date: 20231220
Priority Date: 20221228

Claims (20)

1 . A liquid supply apparatus comprising: a compressed air supply source to compress air; a pressurizing tank to be supplied with the compressed air from the compressed air supply source and accumulate liquid pressurized by the compressed air; a feeder to feed the liquid accumulated in the pressurizing tank to a liquid flow path; a discharge head including an internal flow path through which the liquid fed from the liquid flow path flows, the discharge head having a nozzle to discharge the liquid from the internal flow path; a mitigator on the liquid flow path at a position downstream from the pressurizing tank and upstream from the discharge head, the mitigator to absorb a fluctuation in pressure of the liquid flowing through the liquid flow path; and a circulation path in which the feeder circulates the liquid in the liquid flow path in an order of the pressurizing tank, the mitigator, the discharge head, and the pressurizing tank, wherein the mitigator is a piston presser that includes an accumulator, a subtank, or a shock absorber.
2 . The liquid supply apparatus according to claim 1 , wherein: the feeder circulates the liquid in the circulation path both when the discharge head is discharging the liquid and when the discharge head is not discharging the liquid.
3 . The liquid supply apparatus according to claim 1 , wherein: the feeder is a pump that is on the liquid flow path at a position downstream from the pressurizing tank and upstream from the mitigator, to pressure-feed the liquid in the pressurizing tank toward the mitigator and to the liquid flow path.
4 . The liquid supply apparatus according to claim 3 , further comprising: a pressure gauge that is on the liquid flow path at a position downstream from the mitigator and upstream from the discharge head, to measure the pressure of the liquid flowing through the liquid flow path; and control circuitry configured to control speed of rotation of the pump so that a pressure measured by the pressure gauge be a predetermined value.
5 . The liquid supply apparatus according to claim 3 , wherein: the pump is a diaphragm pump.
6 . The liquid supply apparatus according to claim 3 , further comprising: a filter on the liquid flow path at a position downstream from the pump and upstream from the mitigator, to remove foreign matter from the liquid.
7 . The liquid supply apparatus according to claim 1 , wherein: the pressurizing tank includes a first pressurizing tank from which accumulated liquid is fed toward the mitigator by the feeder, and a second pressurizing tank from which accumulated liquid is supplied to the first pressurizing tank.
8 . The liquid supply apparatus according to claim 7 , further comprising: a first regulator to reduce a pressure of the compressed air supplied from the compressed air supply source to the first pressurizing tank to a first pressure; a second regulator to reduce a pressure of the compressed air supplied from the compressed air supply source to the second pressurizing tank to a second pressure smaller than the first pressure; and a pump to convey the liquid accumulated in the second pressurizing tank to the first pressurizing tank.
9 . The liquid supply apparatus according to claim 8 , wherein: the liquid flowing out from the internal flow path of the discharge head is conveyed to the second pressurizing tank via the liquid flow path, and the feeder includes the first pressurizing tank, the second pressurizing tank, the first regulator, the second regulator, and the pump, to feed the liquid accumulated in the first pressurizing tank to the liquid flow path.
10 . The liquid supply apparatus according to claim 8 , further comprising: a pressure gauge on the liquid flow path at a position downstream from the mitigator and upstream from the discharge head, to measure the pressure of the liquid flowing through the liquid flow path; and control circuitry configured to control a pressure reduction operation by the first regulator and the second regulator so that the pressure measured by the pressure gauge be a predetermined value.
11 . The liquid supply apparatus according to claim 7 , further comprising: a flow rate control valve on the liquid flow path at a position downstream from the first pressurizing tank and upstream from the mitigator, to control the flow rate of the liquid on the liquid flow path.
12 . The liquid supply apparatus according to claim 11 , further comprising: a flow meter on the liquid flow path at a position downstream from the first pressurizing tank and upstream from the discharge head, to measure the flow rate of the liquid flowing through the liquid flow path; and control circuitry configured to control an opening degree of the flow rate control valve on a basis of the flow rate measured by the flow meter.
13 . The liquid supply apparatus according to claim 1 , further comprising: another mitigator on the liquid flow path at a position downstream from the discharge head and upstream from the pressurizing tank, to absorb the fluctuation in pressure of the liquid flowing through the liquid flow path.
14 . The liquid supply apparatus according to claim 13 , wherein: said another mitigator is a piston presser that includes an accumulator, a subtank, or a shock absorber.
15 . The liquid supply apparatus according to claim 13 , wherein: said another mitigator is immediately downstream from the discharge head on the liquid flow path.
16 . The liquid supply apparatus according to claim 1 , wherein: the discharge head is an inkjet head to operate a needle using an actuator to open and close the nozzle.
17 . The liquid supply apparatus according to claim 1 , wherein: the pressurizing tank is supplied with air compressed by the compressed air supply source to a pressure equal to or greater than atmospheric pressure.
18 . The liquid supply apparatus according to claim 1 , further comprising: a stirrer disposed within the pressurizing tank to stir the liquid accumulated therein.
19 . A liquid application apparatus, comprising: a liquid supply apparatus to discharge liquid onto an installation surface; a carrying device to move the liquid supply apparatus; and a support to support the liquid supply apparatus, the liquid supply apparatus including: a compressed air supply source to compress air; a pressurizing tank to be supplied with the compressed air compressed by a compressed air supply source and accumulate liquid pressurized by the compressed air; a feeder to feed the liquid accumulated in the pressurizing tank to a liquid flow path; a discharge head including an internal flow path through which the liquid fed from the liquid flow path flows, the discharge head having a nozzle to discharge the liquid from the internal flow path; a mitigator on the liquid flow path at a position downstream from the pressurizing tank and upstream from the discharge head, the mitigator to absorb a fluctuation in pressure of the liquid flowing through the liquid flow path; and a circulation path in which the feeder circulates the liquid in the liquid flow path in an order of the pressurizing tank, the mitigator, the discharge head, and the pressurizing tank, wherein the mitigator is a piston presser that includes an accumulator, a subtank, or a shock absorber.
20 . A liquid supply apparatus comprising: a compressed air supply source to compress air; a pressurizing tank to be supplied with the compressed air from the compressed air supply source and accumulate liquid pressurized by the compressed air; a feeder to feed the liquid accumulated in the pressurizing tank to a liquid flow path; a discharge head including an internal flow path through which the liquid fed from the liquid flow path flows, the discharge head having a nozzle to discharge the liquid from the internal flow path; a mitigator on the liquid flow path at a position downstream from the pressurizing tank and upstream from the discharge head, the mitigator to absorb a fluctuation in pressure of the liquid flowing through the liquid flow path; a circulation path in which the feeder circulates the liquid in the liquid flow path in an order of the pressurizing tank, the mitigator, the discharge head, and the pressurizing tank; and another mitigator on the liquid flow path at a position downstream from the discharge head and upstream from the pressurizing tank, to absorb the fluctuation in pressure of the liquid flowing through the liquid flow path, wherein said another mitigator is a piston presser that includes an accumulator, a subtank, or a shock absorber.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2022-211980, filed on Dec. 28, 2022, and Japanese Patent Application No. 2023-189683, filed on Nov. 6, 2023, in the Japan Patent Office, the entire disclosure of each of which is hereby incorporated by reference herein. BACKGROUND Technical Field Embodiments of the present disclosure relate to a liquid supply apparatus and a liquid discharge apparatus. Related Art In an ink supply apparatus that supplies ink and the like, as typified by an inkjet, in order to convey a high-viscosity ink having a large amount of solid components and high settleability in a dispersed state, a technology that relates to an operation is known (which, hereinafter, may be referred to as flow-through) in which the ink is conveyed by being circulated by taking, as part of the flow path, a liquid chamber for the ink in the discharge head. In addition, as technology for discharging a high-viscosity ink (of about 1000 mPa·s, for example) that cannot be discharged by a normal inkjet method, an airless spray is known for which a high pressure is applied to the ink and the ink is vigorously discharged from a spray gun tip hole to atomize and coat the ink. Where the above-described inkjet technology is concerned, in the case of a technology using hydraulic head pressure, it is difficult to convey the high-viscosity ink by circulating same because the circulation structure is under a pressure close to atmospheric pressure. If the conveyance through circulation cannot be performed, there is advancement of ink separation and precipitation, an abnormal image caused by a drop in ink concentration and discharge failure due to nozzle clogging caused by ink solid precipitate occur, and there is a problem that the ink cannot be blown over a distance by using a fluctuating pressure under meniscus control. Furthermore, in the case of an airless spray, there is a problem that, although high-viscosity ink can be discharged over a distance, there is advancement of ink separation and precipitation due to a structure in which the high-viscosity ink cannot flow through the discharge head, and discharge failure occurs due to an abnormal image caused by a drop in ink concentration, nozzle clogging caused by ink solid precipitate, and the like. As such inkjet technology, a configuration is disclosed that includes a degassing unit and wherein a differential pressure is provided between a filling tank upstream of a discharge head and a drain tank downstream thereof to produce flow-through, and in order to supply ink to both tanks so that the ink in the filling tank and the drain tank is not depleted even if large droplets are discharged, a configuration in which, in a case where the ink in the filling tank or the drain tank is depleted, a state where the ink constantly flows through in the discharge head is maintained while a flow path is switched by an electromagnetic valve or the like so that a main tank and the filling tank or the drain tank communicate with each other is implemented using one pump. SUMMARY To solve the above-described problem and achieve the above-described object, according to an embodiment of the present disclosure, a liquid supply apparatus includes a compressed air supply source, a pressurizing tank, a feeder, a discharge head, a mitigation device, and a circulation path. The compressed air supply source compresses air. The pressurizing tank is supplied with the compressed air from the compressed air supply source and accumulates liquid pressurized by the compressed air. The feeder feeds the liquid accumulated in the pressurizing tank to a liquid flow path. The discharge head includes an internal flow path through which the liquid fed from the liquid flow path flows. The discharge head has a nozzle to discharge the liquid from the internal flow path. The mitigation device is installed on the liquid flow path at a position downstream from the pressurizing tank and upstream from the discharge head. The mitigation device absorbs a fluctuation in pressure of the liquid flowing through the liquid flow path. In the circulation path, the feeder circulates the liquid in the liquid flow path in an order of the pressurizing tank, the mitigation device, the discharge head, and the pressurizing tank. According to another embodiment of the present disclosure, a liquid application apparatus includes a liquid supply apparatus, a carrying device, and a support. The liquid supply apparatus discharges liquid onto an installation surface. The carrying device moves the liquid supply apparatus. The support supports the liquid supply apparatus. The liquid supply apparatus includes a compressed air supply source, a pressurizing tank, a feeder, a discharge head, a mitigation device, and a circulation path. The compressed air supply source compresses air. The pressurizing tank is supplied with the com