JP2014177045A5

JP2014177045A5 -

Info

Publication number: JP2014177045A5
Application number: JP2013052835A
Authority: JP
Filing date: 2013-03-15
Publication date: 2017-01-12
Anticipated expiration: 2033-03-15

Description

以上に説明したものは一例であり、本発明は、次の態様毎に特有の効果を奏する。
（態様１）
駆動ＩＣ３０２等の駆動部から圧電素子３０４に駆動波形を供給する回路上のアナログスイッチ３０３等の抵抗体の電気抵抗値を切換え可能に構成した。これによれば、上記実施形態について説明したように、加熱電圧を印加されるようなヒータなどの加熱手段を加圧液室毎に設けることでなく、微駆動波形を圧電素子に供給することでもなく、液滴吐出のとき駆動波形が圧電素子に供給されたときの電気抵抗値を切換えられる抵抗体を構成した。抵抗体の電気抵抗値を切換えられるので、駆動波形の供給によって発熱する抵抗体の発熱量を切換え、加圧液室の液体温度を制御することができる。例えば、加圧液室毎に設けた温度センサによって加圧液室の液体温度を測定したり、あるいは装置内部の温度を検出して液滴吐出ヘッドの駆動履歴から加圧液室の液体温度を推定したりする。その検出又は推定した加圧液室の液体温度に基づき、低い温度の加圧液室に対応する抵抗体の電気抵抗値を高めに切換えてその抵抗体の発熱を高めて加圧液室の液体を、低めの電気抵抗値の場合よりも上昇させる。駆動部からの駆動波形が抵抗体を介して圧電素子に供給されるが、抵抗体の電気抵抗値が変化しても、圧電素子内の電圧値及び電流値は、略変化しない電気抵抗値の変化範囲が存在することが実験からわかっている。この変化範囲内で電気抵抗値を切換えれば、圧電素子の変形に影響を与えることは少なく、液滴の吐出特性に影響を及ぼすことは少ない。以上説明のように、本発明によれば、従来の微駆動波形よりも電圧値が大きい駆動波形を用いて加圧液室毎の液体の温度を制御でき、ヘッド全体における温度分布を従来に比して良好に低減することができる。
（態様２）
（態様１）において、抵抗体は、電気抵抗値を切換え可能なスイッチング手段である。これによれば、上記実施形態について説明したように、液滴吐出のとき駆動波形が圧電素子に供給されたときの電気抵抗値を切換えられる。
（態様３）
（態様２）において、スイッチング手段は複数のスイッチング素子で構成され、少なくともいずれかのスイッチング素子を介して駆動部から駆動波形を圧電素子に供給する。これによれば、上記実施形態について説明したように、複数のスイッチング素子を切換えて、液滴吐出のとき駆動波形が圧電素子に供給されたときの電気抵抗値を切換えられる。
（態様４）
（態様３）において、複数のスイッチング素子は、並列接続されている。これによれば、上記実施形態について説明したように、簡単な構成で、液滴吐出のとき駆動波形が圧電素子に供給されたときの電気抵抗値を切換えられる。
（態様５）
（態様１）において、加圧液室の液体温度を検出する温度検出手段をそれぞれ設け、温度検出手段によって検出した複数の加圧液室内の液体温度のうち、最も高い液体温度との温度差が減るように、加熱対象の加圧液室に対応する抵抗体の電気抵抗値を切換える。これによれば、上記実施形態について説明したように、圧電素子に供給される駆動波形を用いて加圧液室毎の液体を加熱でき、ヘッド全体における温度分布を低減することができる。
（態様６）
（態様５）において、温度検出手段が、複数の加圧液室を複数のグループに分割してグループ毎の加圧液室の液体温度を検出し、検出した液体温度が低いグループ内の抵抗体の電気抵抗値を切換える。これによれば、上記実施形態について説明したように、温度検出手段の数を削減できる。
（態様７）
（態様６）において、液体温度が高いグループ内の抵抗体の電気抵抗値より、液体温度が高いグループ以外のグループ内の抵抗体の電気抵抗値を大きくなるように切換える。これによれば、上記実施形態について説明したように、温度検出手段及び制御回路を削減できる。
（態様８）
（態様６）又は（態様７）において、複数のグループ間の温度差によって抵抗体の電気抵抗値を大きくするグループにおけるノズル孔の数を変更する。これによれば、上記実施形態について説明したように、これによれば、上記実施形態について説明したように、低温のグループの全てのノズルではなく、電気抵抗値を上げる抵抗体に対応する加圧液室のノズル孔の数を制御することにより、さらに細かい加熱制御ができる。
（態様９）
（態様１）において、圧電素子の静電容量成分と抵抗体の抵抗成分とで構成されるローパスフィルタに駆動波形を通過させたときの駆動波形の変形とほぼ同じ形状になるよう抵抗体に供給する駆動波形を予めなまらせる。これによれば、上記実施形態について説明したように、抵抗体の電気抵抗値の変化による吐出特性の変化を最小限に抑えることができる。
（態様１０）
（態様１）〜（態様９）のいずれかの液滴吐出装置が備える液滴吐出ヘッドで記録液剤を媒体に吐出して画像形成を行う。これによれば、上記実施形態について説明したように、これによれば、上記実施形態について説明したように、吐出特性に優れ、安定した画像形成を行うことができる。 What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect 1)
The electrical resistance value of the resistor such as the analog switch 303 on the circuit for supplying the drive waveform to the piezoelectric element 304 from the drive unit such as the drive IC 302 can be switched. According to this, as described in the above embodiment, a heating means such as a heater to which a heating voltage is applied is not provided for each pressurized liquid chamber, but a fine driving waveform is supplied to the piezoelectric element. In addition, a resistor capable of switching the electric resistance value when the drive waveform is supplied to the piezoelectric element during droplet discharge is configured. Since the electrical resistance value of the resistor can be switched, the amount of heat generated by the resistor that generates heat by supplying the drive waveform can be switched to control the liquid temperature in the pressurized liquid chamber. For example, the liquid temperature in the pressurized liquid chamber is measured by a temperature sensor provided for each pressurized liquid chamber, or the liquid temperature in the pressurized liquid chamber is determined from the driving history of the droplet discharge head by detecting the temperature inside the apparatus. Or estimate. Based on the detected or estimated liquid temperature of the pressurized fluid chamber, the electrical resistance value of the resistor corresponding to the pressurized fluid chamber at a low temperature is switched to a higher value to increase the heat generation of the resistor, thereby increasing the fluid in the pressurized fluid chamber. Is increased as compared with the case of a lower electric resistance value. The drive waveform from the drive unit is supplied to the piezoelectric element through the resistor. However, even if the electric resistance value of the resistor changes, the voltage value and current value in the piezoelectric element do not substantially change. Experiments have shown that there is a range of change. If the electric resistance value is switched within this change range, the deformation of the piezoelectric element is hardly affected, and the ejection characteristics of the droplet are hardly affected. As described above, according to the present invention, the temperature of the liquid in each pressurized liquid chamber can be controlled using a driving waveform having a voltage value larger than that of the conventional fine driving waveform, and the temperature distribution in the entire head can be compared with the conventional one. And can be reduced satisfactorily.
(Aspect 2)
In (Aspect 1), the resistor is a switching means capable of switching an electric resistance value. According to this, as described in the above embodiment, the electric resistance value when the driving waveform is supplied to the piezoelectric element when the droplet is discharged can be switched.
(Aspect 3)
In (Aspect 2), the switching means includes a plurality of switching elements, and supplies a drive waveform from the drive unit to the piezoelectric elements via at least one of the switching elements. According to this, as described in the above embodiment, the electrical resistance value when the drive waveform is supplied to the piezoelectric element at the time of droplet discharge can be switched by switching a plurality of switching elements.
(Aspect 4)
In (Aspect 3), the plurality of switching elements are connected in parallel. According to this, as described in the above embodiment, the electric resistance value when the drive waveform is supplied to the piezoelectric element when the droplet is discharged can be switched with a simple configuration.
(Aspect 5)
In (Aspect 1), temperature detecting means for detecting the liquid temperature in the pressurized liquid chamber is provided, and the temperature difference from the highest liquid temperature among the liquid temperatures in the plurality of pressurized liquid chambers detected by the temperature detecting means is The electric resistance value of the resistor corresponding to the pressurized liquid chamber to be heated is switched so as to decrease. According to this, as described in the above embodiment, the liquid for each pressurized liquid chamber can be heated using the drive waveform supplied to the piezoelectric element, and the temperature distribution in the entire head can be reduced.
(Aspect 6)
In (Aspect 5), the temperature detecting means divides the plurality of pressurized liquid chambers into a plurality of groups to detect the liquid temperature in the pressurized liquid chambers for each group, and the resistor in the group with the detected low liquid temperature Switches the electrical resistance value. According to this, as described in the above embodiment, the number of temperature detecting means can be reduced.
(Aspect 7)
In (Aspect 6), the electrical resistance value of the resistor in the group other than the group having the high liquid temperature is switched to be larger than the electrical resistance value of the resistor in the group having the high liquid temperature. According to this, as described in the above embodiment, the temperature detecting means and the control circuit can be reduced.
(Aspect 8)
In (Aspect 6) or (Aspect 7), the number of nozzle holes in the group in which the electrical resistance value of the resistor is increased is changed by a temperature difference between the plurality of groups. According to this, as described in the above embodiment, according to this, as described in the above embodiment, not all the nozzles of the low temperature group, but the pressurizing corresponding to the resistor that increases the electric resistance value. By controlling the number of nozzle holes in the liquid chamber, finer heating control can be performed.
(Aspect 9)
In (Aspect 1), the drive waveform is supplied to the resistor so as to have substantially the same shape as that of the drive waveform when the drive waveform is passed through a low-pass filter composed of the capacitance component of the piezoelectric element and the resistance component of the resistor The drive waveform to be smoothed in advance. According to this, as described in the above embodiment, it is possible to minimize the change in the ejection characteristics due to the change in the electrical resistance value of the resistor.
(Aspect 10)
An image is formed by discharging a recording liquid onto a medium by a droplet discharge head provided in any of the droplet discharge apparatuses according to (Aspect 1) to (Aspect 9). According to this, as described in the above-described embodiment, according to this, as described in the above-described embodiment, it is possible to perform stable image formation with excellent ejection characteristics.

Claims

A plurality of nozzle holes for discharging droplets, a plurality of pressurized liquid chambers communicating with the nozzle holes, and a pressure change in the pressurized liquid chamber via a vibration plate constituting a part of the pressurized liquid chamber. In a droplet discharge apparatus including a droplet discharge head including a plurality of piezoelectric elements to be applied and a drive unit that supplies a drive waveform to the piezoelectric elements,
A droplet discharge device characterized in that the electrical resistance value of a resistor on a circuit for supplying a drive waveform from the drive unit to the piezoelectric element can be switched.

The droplet discharge device according to claim 1,
The droplet discharge apparatus according to claim 1, wherein the resistor is a switching means capable of switching an electric resistance value.

The droplet discharge device according to claim 2,
The liquid droplet ejection apparatus, wherein the switching unit includes a plurality of switching elements, and supplies a driving waveform from the driving unit to the piezoelectric elements via at least one of the switching elements.

The droplet discharge device according to claim 3.
Wherein the plurality of switching elements, a droplet discharge device, characterized in that connected in parallel.

The droplet discharge device according to claim 1,
Provided temperature detecting means for detecting the liquid temperature of the pressurized liquid chamber respectively, of the previous SL plurality of pressurized liquid chamber of the liquid temperature detected by said temperature detecting means, so that the temperature difference between the highest liquid temperature decreases In addition, the droplet discharge device is characterized in that the electric resistance value of the resistor corresponding to the pressurized liquid chamber to be heated is switched.

The droplet discharge device according to claim 5,
It said temperature detecting means, before Symbol detects the liquid temperature of the liquid room of each group by dividing a plurality of pressurized liquid chamber into a plurality of groups, the electrical of the resistor in the detected liquid temperature is low group A droplet discharge device characterized by switching a resistance value.

The droplet discharge device according to claim 6.
A droplet discharge device, wherein the electrical resistance value of the resistor in a group other than the group having a high liquid temperature is switched to be larger than the electrical resistance value of the resistor in a group having a high liquid temperature.

In the droplet discharge device according to claim 6 or 7,
The droplet discharge device according to claim 1, wherein the number of nozzle holes in the group in which the electric resistance value of the resistor is increased is changed by a temperature difference between the plurality of groups.

The droplet discharge device according to claim 1,
A drive waveform supplied to the resistor so as to have substantially the same shape as the deformation of the drive waveform when the drive waveform is passed through a low-pass filter composed of a capacitance component of the piezoelectric element and a resistance component of the resistor. A droplet discharge device characterized by being smoothed in advance.

An image forming apparatus, wherein a recording liquid agent is ejected onto a medium by a liquid droplet ejection head provided in the liquid droplet ejection apparatus according to claim 1.