JP2014177048A - Droplet discharge device, and droplet-discharge image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a droplet discharge device which suppresses heat from a wiring formed on an actuator substrate, suppresses temperature unevenness of an ink between individual liquid chambers, does not generate variation in ink discharge property between nozzles, has high reliability, and can be miniaturized.SOLUTION: The droplet discharge device includes nozzles 1 for discharging the ink, a nozzle plate 2 in which at least one nozzle 1 is formed, a channel plate 101 forming individual liquid chambers 3 partitioned by partition walls, and a pressure generating substrate 14 where pressure generating means 15 for making the nozzle 1 discharge the ink is arranged. A high heat transmitting member 200 is formed between the channel plate 101 and the pressure generating substrate 14.

Description

  The present invention relates to a droplet discharge apparatus and a droplet discharge image forming apparatus that perform recording by discharging a liquid onto a recording medium.

As one of the image forming apparatuses, an image pattern is formed by ejecting minute droplets of ink from a droplet ejecting apparatus and landing on a recording medium while reciprocating a carriage equipped with the droplet ejecting apparatus in the main scanning direction. A droplet discharge device for forming is known.
In the droplet discharge device for color printing, each color ink is supplied from the yellow, magenta, cyan, and black ink tanks to the common liquid chamber for each color via the ink supply hole. It is supplied from the liquid chamber to the nozzle via each individual liquid chamber.

  Recently, an on-demand type droplet discharge apparatus configured to discharge a minute droplet of ink only when recording is necessary has become mainstream. The liquid droplet ejection device equipped in this includes a piezoelectric type in which the pressure in the individual liquid chamber is increased by the displacement of a piezoelectric element provided as a pressure generation source in the individual liquid chamber and ink is ejected from the nozzle, and a heater is used for the liquid chamber. It is distinguished from a thermal method in which ink is ejected by generating bubbles in the ink. In any method, a pressure generation source is driven by a drive signal from a drive IC chip for driving a droplet discharge device, and ink droplets are discharged from discharge ports to land on a recording medium.

  In recent years, there has been an increasing demand for a reduction in size and cost of the droplet discharge device, and various attempts have been made to incorporate a drive IC chip in the droplet discharge device in order to meet this requirement. As a specific countermeasure, a configuration in which a drive circuit is flip-chip bonded to the inside of a droplet discharge device has been proposed.

  For example, a configuration has been proposed in which a droplet discharge device is miniaturized by flip-chip bonding between a drive circuit actuator substrate and a holding substrate laminated thereon (see, for example, Patent Document 1). In such a configuration, in order to output a drive signal to the drive circuit, it is necessary to pass a current from an external wiring through an FPC (flexible printed circuit board), a bonding wire, a drive signal input pad, and a wiring formed on the actuator substrate. There is.

  When current flows from the external wiring to the drive circuit, heat is generated by electrical resistance from each electrical wiring and electrical element. Among them, the heat generated by the wiring formed on the actuator substrate is transmitted to the ink in the individual liquid chamber via the actuator substrate. The ink in the individual liquid chamber whose temperature has risen due to heat from the wiring formed on the actuator substrate is ejected to the outside through the nozzle. Thereby, the heat from the wiring formed on the actuator substrate is dissipated to the outside.

  By the way, the current from the drive signal input pad flows in the order of the wiring far from the wiring close to the drive signal input pad, so that a high current flows in the wiring close to the drive signal input pad. A relatively low current flows through the wiring at a distant position. Therefore, the amount of heat generated from the wiring varies depending on the position of the wiring formed on the actuator substrate. That is, the wiring near the drive signal input pad generates a relatively larger amount of heat than the wiring located far away. As a result, the ink in the individual liquid chamber close to the drive signal input pad has a relatively higher temperature than the ink in the individual liquid chamber located far from the drive signal input pad.

On the other hand, the ink discharged from the individual liquid chamber is replenished from the ink tank to the individual liquid chamber through the ink supply hole and the common liquid chamber. However, since the common liquid chambers formed along the rows of the individual liquid chambers are elongated, when ink is supplied from the common liquid chamber to the individual liquid chambers, the ink is located at a position far from the individual liquid chambers close to the ink supply holes. It moves sequentially to the liquid chamber. The ink supplied from the ink tank through the ink supply hole is room temperature ink. For this reason, the individual liquid chambers close to the ink supply holes are supplied with ink at a room temperature, whereas the individual liquid chambers far from the ink supply holes flow into the individual liquid chambers when flowing from the ink supply holes. A relatively high temperature ink whose temperature is locally increased by the heat generated from the wiring is supplied.
Such uneven temperature of the ink between the individual liquid chambers causes unevenness of the viscosity of the ink, resulting in variations in the ink discharge characteristics between the discharge ports.

  As a countermeasure against such a problem, a proposal has been made to equalize the ink temperature in the individual liquid chamber by providing a cooling channel in the individual liquid chamber forming member. For example, in the droplet discharge device described in Patent Document 2, a circulation path between the outermost end portion of the flow path plate in which the individual liquid chamber is formed and the individual liquid chamber, a circulation fluid that flows through the circulation path, and a circulation Equipped with a circulation pump for flowing the fluid through the circulation path and a cooler for cooling the circulation fluid, and discharges the heat of the ink in the individual liquid chambers to the circulation fluid, thereby suppressing ink temperature unevenness between the individual liquid chambers A configuration has been proposed. In this configuration, when the heat from the ink in the individual liquid chambers is transmitted to the circulation fluid, the circulation fluid is sent to the cooler provided outside the droplet discharge device by the circulation pump. The ink temperature can be made uniform quickly.

  However, in the configuration described in Patent Document 2, a circulation path between the outermost end of the flow path plate and the individual liquid chamber, a pump for allowing the circulation fluid to flow, and a cooler for cooling the circulation fluid are provided. Therefore, there is a limit to downsizing the droplet discharge device.

  The present invention is for solving the above-described problems in the prior art, and suppresses heat from the wiring formed on the actuator substrate, suppresses ink temperature unevenness between the individual liquid chambers, It is an object of the present invention to provide a highly reliable and small-sized droplet discharge device that does not cause variations in ink discharge characteristics.

  In order to solve the above problems, a liquid droplet ejection apparatus according to the present invention forms a nozzle for ejecting ink, a nozzle plate on which at least one nozzle is formed, and an individual liquid chamber partitioned by a partition wall. A flow path plate and a pressure generation substrate provided with pressure generation means for discharging the ink from the nozzle, and a high heat transfer member is formed between the flow path plate and the pressure generation substrate. It is characterized by.

  According to the present invention, the heat from the wiring formed on the actuator substrate is suppressed, the ink temperature unevenness between the individual liquid chambers is suppressed, and the ink ejection characteristics between the nozzles do not vary. It is possible to provide a droplet discharge device that can be miniaturized with high reliability.

1 is a schematic perspective view showing a configuration in a first embodiment of a droplet discharge device according to the present invention. It is sectional drawing which follows the A-A 'line of FIG. It is sectional drawing which follows the B-B 'line of FIG. It is a schematic sectional drawing which shows the structure in 2nd Embodiment of the droplet discharge apparatus which concerns on this invention, and is a cross section in alignment with the A-A 'line of FIG. It is a schematic sectional drawing which shows the structure in 3rd Embodiment of the droplet discharge apparatus which concerns on this invention, and is a cross section which follows the B-B 'line | wire of FIG. It is a schematic sectional drawing which shows the structure in 4th Embodiment of the droplet discharge apparatus which concerns on this invention, and is a cross section which follows the B-B 'line | wire of FIG. 1 is a perspective view of a droplet discharge image forming apparatus equipped with a droplet discharge device according to the present invention.

  The droplet discharge device according to the present invention includes a nozzle 1 for discharging ink, a nozzle plate 2 on which at least one nozzle 1 is formed, and a flow path plate that forms an individual liquid chamber 3 partitioned by a partition wall. 101 and a pressure generating substrate 14 provided with pressure generating means 15 for discharging the ink from the nozzle 1, and a high heat transfer member 200 is provided between the flow path plate 101 and the pressure generating substrate 14. It is formed.

Next, the droplet discharge apparatus according to the present invention will be described in more detail with reference to the drawings.
Although the embodiments described below are preferred embodiments of the present invention, various technically preferable limitations are attached thereto, but the scope of the present invention is intended to limit the present invention in the following description. Unless otherwise described, the present invention is not limited to these embodiments.

  FIG. 1 is a schematic separated perspective view showing the configuration of the first embodiment of a droplet discharge apparatus according to the present invention. 2 is a sectional view taken along the line A-A 'in FIG. 1, and FIG. 3 is a sectional view taken along the line B-B' in FIG.

  1, 2, and 3, the droplet discharge device includes a nozzle plate 2 on which nozzles 1 (1 y, 1 m, 1 c, 1 k) for discharging ink are formed, and individual nozzles provided for each nozzle. The flow path plate 101 in which the liquid chambers 3y, 3m, 3c and 3k are formed, the high heat transfer substrate 200 as a high heat transfer member patterned in the same shape as the flow path plate 101, and the individual liquid chambers 3y, 3m, 3c, Actuators 15y, 15m, 15c and 15k as pressure generating means for pushing ink in 3k and ejecting ink from nozzle 1, and drive circuits 105a and 105b for outputting ejection signals to actuators 15y, 15m, 15c and 15k , 105c, 105d are protected from the actuator substrate 14 (pressure generating substrate 14) and the drive circuits 105a, 105b, 105c, 105d. A holding substrate 102 for a common liquid chamber forming substrate 103, the liquid supply hole 107y, 107m, 107c, and manifold 104 107k is formed, the housing 106 are stacked in this order. Further, a nozzle cover 113 is provided to protect the nozzle plate. The high heat transfer substrate 200 extends in the X1 direction and the X2 direction, and is in contact with the nozzle cover 113. Further, in order to send a drive signal from the external wiring to the drive circuits 105a, 105b, 105c, and 105d, the FPC 111 is bonded to the end of the holding substrate 102, and the bonding wire 112 and the drive signal input pad 110 are electrically connected to each other. It is connected. In addition, a liquid contact film by atomic layer deposition is formed on the surface of each component in contact with the ink in order to prevent corrosion due to the ink. The subscripts y, m, c, and k correspond to yellow, magenta, cyan, and black colors, respectively.

  When driving signals are sent from the driving circuits 105a, 105b, 105c, and 105d to the actuators 15y, 15m, 15c, and 15k, the FPC 111, the bonding wire 112, the driving signal input pad 110, and the actuator substrate 14 are formed from the external wiring. The drive current flows through the wiring. At that time, heat is generated by electric resistance from the wiring. Heat from the wiring is transferred to the high heat transfer board 200 through the actuator board 14. The heat transmitted to the high heat transfer substrate 200 is cooled by the room temperature liquid supplied from the liquid supply holes 107y, 107m, 107c, and 107k.

  Further, in the present embodiment, the high heat transfer substrate 200 extends in the X1 direction and the X2 direction and is in contact with the nozzle cover 113, and thus is generated from wiring at both ends in the X1 direction and the X2 direction. The heat is transferred to the nozzle cover through the high heat transfer substrate 200 and dissipated to the outside. As a result, the temperature of the ink in the individual liquid chambers 3y, 3m, 3c, and 3k can be maintained substantially constant.

Here, the high heat transfer substrate 200 is preferably made of a metallic material having high thermal conductivity in order to efficiently transfer heat from the wiring to the nozzle cover 113.
Moreover, it is preferable that the heat conductivity of the high heat transfer substrate 200 as the high heat transfer member is higher than the heat conductivity of the flow path plate 101.
For example, when the flow path plate 101 is formed of silicon having a thermal conductivity of 168 W / (mK), the material of the high heat transfer substrate 200 is copper (398 W / (mK)), aluminum, which has a higher thermal conductivity than silicon. (236 W / (mK)) and the like are preferable.

  FIG. 4 is a schematic cross-sectional view showing the configuration of the droplet discharge device according to the second embodiment of the present invention, and corresponds to a cross section taken along the line A-A ′ of FIG. 1.

Referring to FIG. 4, the high heat transfer substrate 200 is provided in a groove formed on a surface of the flow path plate 101 facing the actuator substrate 14 that is a pressure generating substrate.
In the present embodiment, since the high heat transfer substrate 200 is provided in the groove formed in the flow path plate 101, it does not contact the ink. Therefore, the heat from the wiring can be quickly transmitted to the nozzle cover without being transmitted to the ink, so that there is an advantage that heat can be radiated more efficiently than in the first embodiment.

  FIG. 5 is a schematic sectional view showing the configuration of the third embodiment of the droplet discharge apparatus according to the present invention, and corresponds to a section taken along line B-B ′ of FIG. 1.

Referring to FIG. 5, the high heat transfer substrate 200 extends in the Z2 direction along the surface of the nozzle cover 113 and is in contact with the nozzle cover 113.
In the present embodiment, since the high heat transfer substrate 200 extends along the Z2 direction of the nozzle cover 113, the area of the high heat transfer substrate 200 in contact with the nozzle cover 113 is increased. Therefore, there is an advantage that the heat transfer efficiency is higher than that of the first embodiment.

  FIG. 6 is a schematic cross-sectional view showing the configuration of the droplet discharge apparatus according to the fourth embodiment of the present invention, and corresponds to a short plane along the line B-B ′ of FIG. 1.

  Referring to FIG. 6, a second high heat transfer member 201 is provided between the high heat transfer substrate 200 and the nozzle cover 113, and heat from the high heat transfer substrate 200 is transmitted to the second high heat transfer member 201. . Further, the heat from the second high heat transfer member 201 is dissipated to the outside through the nozzle cover 113.

  Here, since the second high heat transfer member 201 has a concave shape, it is easily deformed. Accordingly, the adhesion between the high heat transfer substrate 200 and the second high heat transfer member is increased. As a result, there is an advantage that heat from the high heat transfer substrate 200 can be efficiently transferred to the nozzle cover 113 as compared to the first embodiment.

The second high heat transfer member 201 preferably has a high thermal conductivity. In addition, it is preferable that the heat conductivity of the second high heat transfer member 201 is equal to or higher than the heat transfer coefficient of the high heat transfer substrate 200.
For example, the flow path plate 101 is made of silicon having a thermal conductivity of 168 W / (mK), and the material of the high heat transfer substrate 200 is made of aluminum (236 W / (mK)), which has a higher thermal conductivity than silicon. In this case, the material of the second high heat transfer member 201 is preferably aluminum or copper (398 W / (mK)) having a higher thermal conductivity than aluminum. On the other hand, when the material of the high heat transfer substrate 200 is made of copper, the material of the second high heat transfer member 201 is preferably copper having the same thermal conductivity as that of the high heat transfer substrate 200.
The second high heat transfer member 201 is preferably a flexible member.

  In the present embodiment, the shape of the second high heat transfer member 201 has been described using a concave shape. However, any shape can be used as long as it improves the adhesion between the high heat transfer substrate 200 and the nozzle cover 113. It doesn't matter.

  In the present embodiment, since the adhesion between the high heat transfer substrate 200 and the nozzle cover is increased, the thermal conductivity is increased. Therefore, there is an advantage that the heat from the high heat transfer substrate 200 can be efficiently transmitted to the nozzle cover as compared with the first embodiment.

  FIG. 7 is a schematic perspective view illustrating a configuration of a main part in the droplet discharge image forming apparatus 300. In the droplet discharge image forming apparatus 300, a printing mechanism 302 and the like are accommodated inside the apparatus main body 301. In this printing mechanism 302, an ink cartridge 304 is mounted on a carriage 303 that is movable in the operation direction, and a droplet discharge device of the present invention is mounted under the ink cartridge 304.

  In the above embodiment, the case where the present invention is applied to a droplet discharge device having a four-color integrated form has been described. However, the present invention is applicable to any number of droplet discharge devices of one or more colors. Applicable.

1y, 1m, 1c, 1k: Nozzle 2: Nozzle plates 3y, 3m, 3c, 3k: Individual liquid chambers 4y, 4m, 4c, 4k: Common liquid chamber 14: Actuator substrates 15y, 15m, 15c, 15k: Actuator 101: Flow path plate 102: Holding substrate 103: Common liquid chamber forming substrate 104: Manifold 105a, 105b, 105c, 105d: Drive circuit 106: Housing 107y, 107m, 107c, 107k: Ink supply hole 110: Drive signal input pad 112: Bonding wire 113: Nozzle cover 200: High heat transfer substrate 201: Second high heat transfer member 300: Droplet ejection image forming apparatus 301: Inkjet recording apparatus main body 302: Printing mechanism section 303: Carriage 304: Ink cartridge

JP 2011-167908 A Japanese Patent No. 5045630

Claims (8)

Nozzles from which ink is ejected, nozzle plates on which at least one nozzle is formed, flow path plates that form individual liquid chambers defined by partition walls, and pressure generation for ejecting the ink from the nozzles A pressure generating substrate provided with means,
A droplet discharge device, wherein a high heat transfer member is formed between the flow path plate and the pressure generating substrate. Nozzles from which ink is ejected, nozzle plates on which at least one nozzle is formed, flow path plates that form individual liquid chambers defined by partition walls, and pressure generation for ejecting the ink from the nozzles A pressure generating substrate provided with means,
A groove is formed on the surface of the flow path plate that contacts the pressure generating substrate,
A droplet discharge device, wherein a high heat transfer member is provided in the groove. A nozzle cover for protecting the nozzle plate is provided;
The droplet discharge device according to claim 1, wherein a part of the high heat transfer member is in contact with the nozzle cover.   The droplet discharge device according to claim 3, wherein the high heat transfer member extends along a surface of the nozzle cover.   5. The droplet discharge device according to claim 1, wherein the heat conductivity of the high heat transfer member is higher than the heat conductivity of the flow path plate.   The droplet discharge device according to claim 1, wherein a second high heat transfer member is provided between the high heat transfer member and the nozzle cover.   The liquid droplet ejection apparatus according to claim 6, wherein the second high heat transfer member is a flexible member having high thermal conductivity.   A droplet discharge image forming apparatus on which the droplet discharge device according to claim 1 is mounted.