EP-4613487-B1 - LIQUID JETTING APPARATUS AND CONTROL METHOD OF LIQUID JETTING APPARATUS

EP4613487B1EP 4613487 B1EP4613487 B1EP 4613487B1EP-4613487-B1

Inventors

MIYAGISHI, AKIRA
Okui, Hiroaki
ITO, NOBUAKI

Dates

Publication Date: 20260513
Application Date: 20250304

Claims (13)

A liquid jetting apparatus comprising: a liquid jetting head that includes a nozzle (N) which jets a liquid, a piezoelectric element which corresponds to the nozzle, a vibration plate (14) which vibrates by driving the piezoelectric element, and a detection portion (19) which detects residual vibration of the vibration plate caused by driving of the piezoelectric element; and a control portion (40), wherein the control portion is configured to perform minute vibration driving in which the piezoelectric element is driven with a minute vibration pulse for not jetting the liquid from the nozzle and vibration driving in which the piezoelectric element is driven with a vibration pulse for generating, at the vibration plate, vibration larger than vibration of the vibration plate caused by the minute vibration driving, causes the detection portion to detect, as first residual vibration, the residual vibration caused by continuously performing the vibration driving, causes the detection portion to detect, as second residual vibration, the residual vibration caused by continuously driving the piezoelectric element in order of the minute vibration driving and the vibration driving, and evaluates a variation in a jetting characteristic of the nozzle between a case where the vibration driving is continuous and a case where the vibration driving is not continuous based on the first residual vibration and the second residual vibration detected by the detection portion.
The liquid jetting apparatus according to claim 1, wherein the control portion evaluates the variation in the jetting characteristic of the nozzle based on a phase of the first residual vibration and a phase of the second residual vibration.
The liquid jetting apparatus according to claim 2, wherein the control portion determines that the jetting characteristic of the nozzle varies when the phase of the second residual vibration is not included in a range based on the phase of the first residual vibration.
The liquid jetting apparatus according to claim 1, wherein the control portion evaluates the variation in the jetting characteristic of the nozzle based on an amplitude of the first residual vibration and an amplitude of the second residual vibration.
The liquid jetting apparatus according to claim 4, wherein the control portion determines that the jetting characteristic of the nozzle varies when an amplitude of a first peak of the second residual vibration is not included in a first range based on an amplitude of a first peak of the first residual vibration.
The liquid jetting apparatus according to claim 5, wherein the control portion determines that the jetting characteristic of the nozzle varies when an amplitude of a second peak of the second residual vibration is not included in a second range based on an amplitude of a second peak of the first residual vibration.
The liquid jetting apparatus according to claim 6, wherein the first range is a range in which a value obtained by multiplying the amplitude of the first peak of the first residual vibration by a first coefficient is subtracted from or added to the amplitude of the first peak of the first residual vibration, the second range is a range in which a value obtained by multiplying the amplitude of the second peak of the first residual vibration by a second coefficient is subtracted from or added to the amplitude of the second peak of the first residual vibration, and the second coefficient is smaller than the first coefficient.
The liquid jetting apparatus according to claim 1, wherein the control portion evaluates the variation in the jetting characteristic of the nozzle with a first minute vibration pulse as the minute vibration pulse, and further evaluates the variation in the jetting characteristic of the nozzle with a second minute vibration pulse having a pulse width different from a pulse width of the first minute vibration pulse as the minute vibration pulse.
The liquid jetting apparatus according to claim 1, wherein the control portion evaluates the variation in the jetting characteristic of the nozzle with a first minute vibration pulse as the minute vibration pulse, and further evaluates the variation in the jetting characteristic of the nozzle with a second minute vibration pulse having an amplitude different from an amplitude of the first minute vibration pulse as the minute vibration pulse.
The liquid jetting apparatus according to claim 1, wherein the control portion performs the minute vibration driving by applying the minute vibration pulse to the piezoelectric element at a first timing within a unit period for driving the piezoelectric element and evaluates the variation in the jetting characteristic of the nozzle, and further performs the minute vibration driving by applying the minute vibration pulse to the piezoelectric element at a second timing different from the first timing within the unit period and evaluates the variation in the jetting characteristic of the nozzle.
The liquid jetting apparatus according to claim 1, wherein the control portion evaluates the variation in the jetting characteristic of the nozzle with a first minute vibration pulse including at least one pulse as the minute vibration pulse, and further evaluates the variation in the jetting characteristic of the nozzle with a second minute vibration pulse including the number of pulses different from the number of pulses included in the first minute vibration pulse as the minute vibration pulse.
The liquid jetting apparatus according to claim 1, wherein the control portion causes the detection portion to detect the residual vibration caused by continuously performing the vibration driving for three times as the first residual vibration, causes the detection portion to detect, as the second residual vibration, the residual vibration caused by continuously driving the piezoelectric element in order of the minute vibration driving, the minute vibration driving, and the vibration driving, causes the detection portion to detect, as third residual vibration, the residual vibration caused by continuously driving the piezoelectric element in order of the minute vibration driving, the vibration driving, and the vibration driving, and evaluates the variation in the jetting characteristic of the nozzle based on the first residual vibration, the second residual vibration, and the third residual vibration detected by the detection portion.
The liquid jetting apparatus according to claim 1, wherein the vibration pulse is a pulse for jetting the liquid from the nozzle.

Description

The present application is based on, and claims priority from JP Application Serial Number 2024-031829. BACKGROUND 1. Technical Field The present disclosure relates to a liquid jetting apparatus and a control method of a liquid jetting apparatus. 2. Related Art A liquid jetting apparatus that prints an image by causing a nozzle to jet a liquid such as an ink using a piezoelectric element is known. For example, the liquid jetting apparatus includes a liquid jetting head that jets the liquid filling a pressure chamber from the nozzle by causing the piezoelectric element to vibrate a vibration plate that constitutes a part of the pressure chamber. In this type of liquid jetting apparatus, it is known that a change in viscosity of the liquid affects jetting characteristics of the liquid from the nozzle. For this reason, for example, JP-A-2013-163290 discloses a liquid ejecting apparatus including a control unit that supplies a minute vibration drive signal for generating minute vibration of a liquid in a pressure generating chamber without jetting the liquid from a nozzle opening to a pressure generating unit. Depending on a printed image, continuous jetting in which an ink is continuously jetted to a plurality of pixels and single jetting in which the ink is jetted to only one pixel among the plurality of pixels may be mixed in some cases. In the continuous jetting, jetting driving in which the piezoelectric element is driven with a drive signal including a jetting waveform for jetting the liquid from the nozzle is continuously performed. On the other hand, in the single jetting, the jetting driving described above is not continuous. For this reason, the jetting characteristics of the nozzle vary between the continuous jetting and the single jetting. As described above, it is known that thickening of the liquid is suppressed by performing non-jetting driving in which the piezoelectric element is driven with a drive signal including a minute vibration waveform for not jetting the liquid from the nozzle. Therefore, for example, even in the single jetting, in order to suppress the thickening of the liquid, performing the non-jetting driving instead of the jetting driving in a period when the jetting driving is not performed is considered. In this aspect, variations in the jetting characteristics between the continuous jetting and the single jetting can be reduced by adjusting the minute vibration waveform. Herein, for example, a business model in which a head manufacturer that manufactures the liquid jetting head sells the liquid jetting head to a printing apparatus manufacturer, and the printing apparatus manufacturer assembles the liquid jetting apparatus is considered. In the business model, in many cases, usage conditions of the liquid jetting head such as ink conditions are determined by the printing apparatus manufacturer, not the head manufacturer. When the head manufacturer assembles the liquid jetting apparatus, the head manufacturer also determines the usage conditions and thus can appropriately evaluate the variations in the jetting characteristics described above. On the other hand, in the business model described above, there is a possibility in which the head manufacturer cannot appropriately evaluate the variations in the jetting characteristics in a stage where the head manufacturer manufactures and sells the liquid jetting head. In this case, it is difficult for the head manufacturer to determine an appropriate minute vibration waveform for reducing the variations in the jetting characteristics. For this reason, in the business model described above, the printing apparatus manufacturer needs to appropriately evaluate the variations in the jetting characteristics and to appropriately determine the minute vibration waveform for reducing the variations in the jetting characteristics, and there is a possibility in which this may cause an excessive load on the printing apparatus manufacturer. For this reason, in the business model described above, it is desired that the evaluation of the variations in the jetting characteristics and the determination of the appropriate minute vibration waveform for reducing the variations in the jetting characteristics can be appropriately and easily performed. In particular, it is desired that the variations in the jetting characteristics can be appropriately and easily evaluated. The problems described above are desired to be relatively small even when the manufacturer that manufactures the liquid jetting apparatus and the manufacturer that manufactures the liquid jetting head have the same business model. For example, it is also considered that a user uniquely sets usage conditions different from the usage conditions assumed in advance by the manufacturer of the liquid jetting head or the liquid jetting apparatus, and in this case, the same problems occur. US9649838 discloses a liquid jetting head that detects two types of residual vibrations and evaluates a variat