JPH03219959A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To vibrate a meniscus formed in a dummy delivery port independently of a liquid drip delivery operation of a recording delivery port to easily remove ink mist applied to a delivery port surface at and around the recording delivery port by a construction wherein at least a part of dummy delivery ports communicate with a liquid chamber other than a liquid chamber communicating with the recording delivery port. CONSTITUTION:Dummy liquid paths 7 and dummy delivery ports 10 formed on the upper surface of a substrate 1 are provided for the air vent of an upper liquid chamber 11. At the time of recording, based on a recording signal, a heating element 8 in a recording liquid path 6 is driven to generate a vapor bubble. Subsequently to a liquid drip delivery from a recording delivery port 9 by the pressure of the bubble, ink is supplied from the liquid chamber 11 into the recording liquid path 6. On the other hand, in lower dummy liquid paths 12 and dummy delivery ports 13, at the time of recording an electrostrictive element 15 applies a required pressure to ink in the dummy liquid path 12 independently of the pressure state in the recording liquid path 6, and a meniscus 17 previously formed in the dummy delivery port 13 is projected outside the delivery port. Ink in the dummy liquid path 12 is vibrated so that the ink temporarily covers the recording delivery port 9 and thereabouts.

Description

Detailed Description of the Invention (Graduation Field of Application) The present invention is capable of ejecting ink droplets from the ejection ports by driving pressure generating means provided at each of the ejection ports of the print head based on print information. The present invention relates to an inkjet recording device that performs recording by causing ejection to fly.

[Prior Art] Recording devices such as printers, copiers, and facsimile machines drive an energy generator in a recording head based on transferred image information to print on a recording material such as paper or a thin plastic plate. The camera is configured to record images consisting of patterns of 1 and 7.

The recording device may be an inkjet type,
It can be divided into wire dot type, thermal type, laser beam type, etc. Among them, the inkjet type (inkjet recording bag W) ejects ink (recording liquid) droplets from the ejection opening of the recording head and sprays them onto paper, etc. It is configured to be attached to a recording material for recording.

The inkjet recording apparatus has an excellent advantage over other recording apparatuses in that it can record high-definition images at high speed because it ejects ink into minute droplets.

However, as the density of ejection ports increases, the influence of ink mist generated when droplets are ejected from the ejection ports or when the droplets land on a recording material is increasing.

That is, as a result of the increase in the number of ejection ports per unit area of the ejection port surface of the print head, the ink mist floating in the space between the print head and the recording material (recording medium such as paper or thin plastic plate) and the surrounding space is reduced. The frequency of adhesion to the ejection port surface near the ejection port of the recording head is increasing.

FIG. 9 is a schematic diagram showing an ink droplet flying state when ink mist 33 adheres to the ejection port surface 32 near the recording ejection port 31.

In FIG. 9, when ink mist 33 adheres to the vicinity of the recording outlet 31 on the outlet surface 32 where the liquid path 34 opens, the flying direction of the droplet 35 discharged from the recording outlet 31 is bent by the ink mist 33. Or, in some cases,
A so-called wet ejection failure phenomenon occurs that makes it impossible to eject droplets from the recording ejection port 31, which causes a decrease in the quality of the recorded image.

This tendency is particularly noticeable when the droplet volume is set small in order to obtain a high-definition image.

Therefore, several methods have been proposed to prevent or remove floating ink mist from adhering to the ejection port surface.

For example, a method of providing an ink mist adhesion prevention member between the recording head and the recording material (Japanese Patent Laid-Open No. 54101322)
, a method of installing a member to actively attract
207066) and a method of removing floating ink mist by creating an air flow using a fan or the like (Japanese Patent Application Laid-Open No. 57-84857).

[Technical Problems to be Solved by the Invention] However, when these conventional methods are adopted, there is a technical problem that the recording apparatus becomes large in size.

Furthermore, since the distance between the ejection orifice surface of an inkjet recording head and the recording material is usually narrow, 2 to 3 meters or less, it is extremely difficult to provide the above-mentioned ink mist removal or prevention member in these locations where the density of ink mist is high. It was difficult.

The present invention has been made in view of these technical problems, and does not require extra space, and even if floating ink mist adheres to the ejection port surface, it can be removed in a short time. An object of the present invention is to provide an inkjet recording device that can always maintain good quality of recorded images.

[Means for Solving the Problem] The invention according to claim 1 provides an inkjet recording head having a size capable of holding a meniscus in the vicinity of a recording discharge opening for discharging droplets onto a recording material, and a recording In an inkjet recording device in which a dummy ejection port is arranged that does not eject droplets for printing, at least a part of the dummy ejection port communicates with a liquid chamber different from a liquid chamber communicating with the recording ejection port. To provide an inkjet recording device in which a meniscus formed in the dummy discharge port is vibrated independently of droplet discharge from the recording discharge port, and ink mist attached to the vicinity of the recording discharge port on the discharge port surface can be easily removed. It is.

In addition to the above structure, the invention according to claim 2 provides at least one of a liquid path leading to the dummy ejection port, the liquid chamber with which only the liquid path of the dummy ejection port communicates, and a supply path for supplying ink to the cough liquid chamber. A pressure generating means is disposed on one side, and when a droplet is ejected from the recording ejection port, the pressure generating means causes the meniscus formed in the dummy ejection port to protrude outside the ejection port, and the ink is applied to the recording surface of the ejection port. By applying pressure to the ink in the liquid path of the dummy ejection port to create vibrations with an amplitude that temporarily covers the vicinity of the ejection port, floating ink mist can be generated on the ejection port surface without increasing the size of the device. An object of the present invention is to provide an inkjet recording apparatus that can remove the deposits in a short time even if they are deposited, and can always maintain good quality of recorded images.

〔Example〕

The present invention will be specifically described below with reference to the drawings.

FIG. 1 is an exploded perspective view of a recording head of an inkjet recording apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. 1 is a cross-sectional opening along line 1[[-[[1].

In FIGS. 1 to 3, liquid path walls 2 are formed of photosensitive resin on both sides (upper and lower surfaces) of a substrate 1, and the substrate l
By joining the top plate member 3 and the pace plate member 4 from both sides of the front plate (
A recording head is constructed, which has an ejection port surface 5 on its face (face surface) and is provided with a liquid path and a liquid chamber inside thereof as will be described later.

In this recording head, a plurality of recording liquid passages 6 for recording and one dummy liquid passage 7 on each side of the recording liquid passages 6 are formed on the upper surface of the substrate 1, and these liquid passages 6.7 on the upper surface side are formed.
Each of them is provided with a heating element 8 as a pressure generating means for ejecting droplets.

Each of the recording liquid paths 6 communicates with a recording discharge port 9 that opens on the discharge port surface 5, and each of the dummy liquid paths 7 communicates with a dummy discharge port 10 that opens on the discharge port surface 5.
is connected to.

The recording discharge port 9 discharges droplets for recording, but the dummy discharge port 10 does not discharge droplets for recording.

Further, a liquid chamber 11 is formed on the upper surface side, and all of the upper liquid passages 6.7 communicate with the liquid chamber 11.

On the other hand, a plurality of dummy liquid paths 12 are formed on the lower side of the substrate l, and each of these dummy liquid paths 12 is
It communicates with a dummy discharge port 13 that opens in the discharge port surface 5 .

A liquid chamber 14 is formed on the lower side of the substrate 1, and all of the lower dummy liquid paths 12 communicate with the liquid chamber 14.

Furthermore, an electrostrictive element 15 is provided in the lower liquid chamber 14 .

The dummy ejection port 13 also does not eject droplets for recording.

Ink is supplied to each of the liquid chambers 11.14 from a main ink tank (not shown) through a supply pipe (not shown).

Note that 16 in FIG. 2 indicates the meniscus of the recording ejection port 9, and 17 in FIG. 3 indicates the meniscus of the dummy ejection port 13.

In the above configuration, the dummy liquid path 7 and the dummy ejection ports 10 formed on the upper side of the substrate l are provided partly for the sake of simplicity in manufacturing the inkjet recording head, but from a functional point of view. is provided to vent air from the upper liquid chamber 11, and is designated by the Japanese Patent Publication Publication No. 59/139.
It has the same effect as those described in No. 89 and JP-A-61-35966.

During recording, vapor bubbles are generated on the surface of the heating element 8 in the recording liquid path 6 based on the recording signal, and droplets are ejected from the recording outlet 9 by the pressure of the vapor bubbles, and an image is recorded. Ru.

As the droplets are ejected, ink is supplied from the liquid chamber 11 into the recording liquid path 6 by capillary force.

On the other hand, in the lower dummy liquid path 12 and dummy ejection port 13, the electrostrictive element 15 applies a predetermined pressure to the ink in the dummy liquid path 12, independently of the pressure state in the recording liquid path 6 during recording. is applied.

The driving pressure by the electrostrictive element 15 is applied in advance to the inside of the dummy liquid path 12 so that the meniscus 17 formed in the dummy ejection port 13 protrudes outside the ejection port and the ink temporarily covers the periphery of the recording ejection port 9. The ink is set to vibrate.

FIGS. 4A to 4E are schematic cross-sectional views of the ejection port portion for explaining the driving state of the recording head described in FIGS. 1 to 3. FIGS.

In FIG. 4, the discharge port 9 of the recording liquid path 6 is
(state A) where the meniscus 16 extends out of the discharge port 9)
, the meniscus 17 formed at the dummy ejection port 13 of the dummy liquid path 12 immediately before separating and flying as a recording droplet 18 (state B) is a dummy ejection port due to ink pressure applied by driving the electrostrictive element 15. 13 Extend it outside.

The meniscus 17 of this dummy ejection port 13 reaches the maximum extended state (state D) after the droplet 18 from the recording ejection port 9 separates and flies (state C).

Due to the protrusion of the meniscus 17 of the dummy ejection port 13, the vicinity of the recording ejection port 9 on the ejection port surface 5 is covered with protruding ink, and the ink mist 19 adhering to the ejection port surface 5 is shown in (B) to (D). It is incorporated into the ink as shown in FIG.

Thereafter, as the pressure in the dummy liquid path 12 decreases, the ink that overflows onto the ejection port surface 5 is absorbed into the dummy liquid path 12 through the dummy ejection port 13, resulting in the state shown in (E). The meniscus 16 returns to its original state.

Note that the separation and ejection of the recording droplets 18 is performed as shown in (C) in the illustrated example.
As shown in FIG. 3, this is carried out immediately after the meniscus 17 of the dummy ejection port 13 absorbs and combines the ink mist 19 on the ejection port surface 5.

Setting the driving frequency of the electrostrictive element 15 in the liquid chamber 14 in accordance with the driving conditions for recording of the inkjet recording head so as not to affect the desired flight state of the droplet 18,
By repeating the operation process explained above in Figure 4,
Ink mist 19 attached to the ejection port surface 5 of the inkjet recording head can be removed.

FIG. 5 is an exploded perspective view showing the recording head 20 of another embodiment of the inkjet recording apparatus according to the present invention, and FIG. 6 is a sectional view taken along the line Vl--Vl in FIG.
This figure is a schematic block diagram showing the ink supply system of the recording head 20 of FIG. 5, and FIG. 8 is a schematic perspective view of an inkjet recording apparatus equipped with the recording head of FIG. 5.

In the embodiments shown in FIGS. 5 to 8, parts corresponding to those in the embodiments shown in FIGS. 1 to 4 are designated by the same numbers.

5 and 6, a liquid channel wall 2 is formed of photosensitive resin on a substrate l joined to a base plate member 4, and a discharge port plate 21 joined to the substrate 1 has a liquid passage wall 2 formed in the center thereof. a plurality of recording ejection ports 9 arranged in a section, dummy ejection ports IO arranged one at each end of the recording ejection ports 90, and dummy ejection ports 13 arranged in a row on each side of the recording ejection ports 9. is formed.

The upper surface of the discharge port plate 21 forms the discharge port surface 5 .

Each recording discharge port 9 communicates with a corresponding recording liquid path 6, and a heating element 8 as a pressure generating means for recording is provided in each recording liquid path 6.

The dummy discharge ports 10 at both ends communicate with dummy liquid passages 7 at both ends, and a heating element 8 is provided in the dummy liquid passages 7.
A is provided.

The dummy discharge ports 13 formed in the two rows on both sides communicate with the dummy liquid paths 12, respectively.

The recording liquid path 6 and the dummy liquid path 7 are separated from the dummy liquid path 12 by the liquid path wall 2.

The recording ejection port 9 ejects droplets for recording, but the dummy ejection port 10 and the dummy ejection port 13 do not eject droplets for recording.

In addition, liquid chambers 11 partitioned from each other are provided in the recording head 20.
．． 14, the recording ejection ports 9 and the dummy ejection ports 10 all communicate with the liquid chamber 11, and the dummy ejection ports 13 in the two rows on both sides all communicate with the liquid chamber 14. .

In the above configuration, the dummy ejection ports 10 provided at both ends of the recording ejection port 9 are provided in part for the convenience of manufacturing the inkjet recording head, but from a functional standpoint, Liquid chamber 1 with which each recording discharge port 9 communicates
It is installed to vent the air in
It has the same effect as those described in No. 9-13989 and JP-A No. 61-35966.

Further, in FIG. 6, 16 indicates a meniscus of the recording ejection port 9, and 17 indicates a meniscus of the dummy ejection port 13.

In FIG. 7, the recording head/domain 20 is mounted on a carriage 22 that reciprocates along a recording medium such as paper (FIG. 8).

The eighth view is a schematic overall perspective view of the ink jet recording apparatus equipped with the recording gutter 20 shown in FIG. 7, and in the figure, the carriage 22 on which the recording gutter 20 is mounted is
It is configured to reciprocate along a guide shaft 28 installed to extend left and right in front of the recording medium 27.

Further, a main ink tank 25 for supplying ink to the recording head 20 on the carriage 22 is arranged on the main body side of the inkjet recording apparatus.

In FIG. 7, the liquid chambers 11 and 14 in the recording head 20 are connected to a main ink tank 25 on the recording apparatus main body side through ink supply tubes 23 and 24 made of ethylene vinyl acetate resin, respectively. .

By the way, in the inkjet recording apparatus as shown in Part 7, during recording, the ink supply tubes 23 and 24 are bent when the carriage 22 moves.
The ink pressure supplied through these tubes 23,24 will vary widely.

However, since a sub-tank 26 having an air buffer effect is connected in the middle of one of the ink supply tubes 23, fluctuations in ink pressure due to bending of the tube 23 are absorbed by the sub-tank 26.

Therefore, stable droplet discharge can be performed from the recording discharge port 9 communicating with one of the liquid chambers 11 in the recording head 20.

Since the ink pressure fluctuation due to the bending of the ink supply tube 24 directly acts on the other liquid chamber 14, meniscus vibration occurs in the meniscus 17 of the dummy ejection port 13.

Therefore, depending on the magnitude of this ink pressure fluctuation, the liquid chamber 14
By appropriately determining the volume and the shape of the dummy outlet 13, the meniscus 17 of the dummy outlet 13 can be set to vibrate as follows.

That is, the meniscus 17 can be set to have an amplitude such that the meniscus 17 extends outward from the dummy ejection port 13 and the ink temporarily covers the periphery of the recording ejection port 9 due to the meniscus vibration.

By setting the vibration of the meniscus 17 in this way, the ink mist removal operation and the substantially overlapping operation described in FIG. The attached ink mist 19 (FIG. 4) can be combined with the overhanging ink and removed.

That is, during recording, the recording liquid path 6 is
By driving the heating element 8 inside, vapor bubbles are generated on its surface, and the pressure causes droplets to be ejected from the recording ejection port 9, thereby recording an image.

As the droplets are ejected, ink is supplied from the liquid chamber 11 into the recording liquid path 6 by capillary force.

On the other hand, during recording, the ink in the dummy liquid path 12 is maintained at a predetermined pressure by pressure fluctuations in the liquid chamber 14 based on the movement of the carriage 22, independently of the pressure state in the recording liquid path 6. is applied.

The driving pressure of the dummy liquid path 12 due to the movement of the carriage 22 causes the meniscus 17 formed in the dummy ejection port 13 to overhang outside the ejection port, and the ink is transferred to the recording ejection port 9.
The ink in the dummy liquid path 12 is set to vibrate so as to temporarily cover the periphery of the dummy liquid path 12.

The plurality of recording ejection ports 9 are selectively driven by a print signal to eject ink droplets (droplets) for recording, and the dummy ejection ports 13 eject ink droplets for recording. Instead, as described above, the meniscus 17 is made to protrude outside the ejection port to remove ink mist attached to the ejection port surface 11.

〔Effect of the invention〕

As is clear from the above description, according to the invention of claim 1, the inkjet recording head has a size that can hold a meniscus in the vicinity of the recording discharge opening that discharges 'a droplets onto the recording material. and an inkjet recording apparatus in which dummy ejection ports that do not eject droplets for recording are arranged, at least a part of the dummy ejection ports communicating with a liquid chamber different from a liquid chamber communicating with the recording ejection ports. By vibrating the meniscus formed at the dummy ejection port independently of droplet ejection from the recording ejection port, ink mist attached to the ejection port surface near the recording ejection port can be easily removed. An inkjet recording device capable of recording stable, high-quality images is provided.

In addition to the above structure, the invention according to claim 2 provides at least one of a liquid path leading to the dummy ejection port, the liquid chamber with which only the liquid path of the dummy ejection port communicates, and a supply path for supplying ink to the cough liquid chamber. A pressure generating means is disposed on one side, and when a droplet is ejected from the recording ejection port, the pressure generating means causes the meniscus formed in the dummy ejection port to protrude outside the ejection port, and the ink is applied to the recording surface of the ejection port. The structure is configured to apply pressure to the ink in the liquid path of the dummy ejection port to generate vibrations having an amplitude that temporarily covers the vicinity of the ejection port.
Furthermore, even if floating ink mist adheres to the ejection port surface, it can be removed in a short time without increasing the size of the device, and inkjet recording can always maintain good quality of recorded images. Equipment is provided.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing a -★ embodiment of a recording head of an inkjet recording apparatus according to the present invention, FIG. 2 is a partial sectional view taken along the line ■-■ in FIG. 1, and FIG. Line in the diagram■
4 (A) to (E) are schematic sectional views for explaining the driving operation of the recording head in FIG. 1, and FIG. 5 is an inkjet recording apparatus according to the present invention. FIG. 6 is an exploded perspective view showing another embodiment of the recording head of FIG. A schematic diagram showing the configuration of the supply system; FIG. 8 is a schematic perspective view of an inkjet recording apparatus equipped with a carriage equipped with the recording head shown in FIG. 5; FIG. It is a longitudinal section opening schematically showing a state in which droplets are ejected and flying. 1----One substrate, 2---One liquid path wall, 5---One discharge port surface, 6---Recording liquid path, 7.12---Dummy liquid path, 8 Heat generating element, 9----1 recording ejection port, 10'---
---Dummy discharge port, 11--Liquid chamber, l 2----
Dummy liquid path, 13--Dummy discharge port, 14----One liquid chamber, 15-----Electrostrictive element, 16.17--Meniscus, 1B----One droplet, 19-----Ink mist, 20---One recording head, 21--One discharge port plate, 22-----Carriage, 23.24-----
Ink supply tube, 25-----Main ink tank, 26--Sub tank, 27--Recording medium.

Claims (2)

[Claims] (1) A dummy ejection port that is large enough to maintain a meniscus in the ejection port and does not eject droplets for recording is installed near the print ejection port that ejects droplets onto the recording material of the inkjet recording head. In the inkjet recording apparatus, at least a part of the dummy ejection opening communicates with a liquid chamber different from a liquid chamber communicating with the recording ejection opening. (2) Pressure generating means is disposed in at least one of the liquid path leading to the dummy ejection port, the liquid chamber with which only the liquid path of the dummy ejection port communicates, and the supply path that supplies ink to the liquid chamber. When ejecting droplets from the recording ejection port,
The pressure generating means applies pressure to the dummy ejection port to cause the meniscus formed in the dummy ejection port to protrude outside the ejection port and cause the ink to vibrate with an amplitude that temporarily covers the vicinity of the recording ejection port on the ejection port surface. 2. The inkjet recording apparatus according to claim 1, wherein the ink is applied to the ink in the liquid path.