JPH0428559A - Ink jet recording device - Google Patents

Abstract

PURPOSE:To remove foreign matters such as dirt or the like promptly without fail out of ejection ports of a recording head when the same are clogged up with the foreign matters by a method wherein a fluid injecting means is provided, and the injection of the fluid is made at specified times into the inside of the recording head through the ejection ports. CONSTITUTION:In an ink-jet recording device that makes recording with ink ejected from a recording head 2 to a recording matter, fluid (air) is injected at a specified timing into the inside of the recording head 2 through ejection ports 31 provided to the recording head 2, and is made to flow through the inside of the recording head 2 for circulation of ink. When the recording head 2 is positioned facing a malfunction-recovery device 14 for ejection, the malfunction-recovery device 14 is pressed against the faces of the ejection ports and after this, highly compressed air is ejected through air exhausts 18 so that the compressed air is injected into the inside of the recording head 2 through the ejection ports 31. After injection of the compressed air is accomplished, circulation of the ink is made through a route running from and coming back to an ink supply tank 13 through an ink supply tube 11, a liquid chamber 30, and an ink return tube 12 with an ink delivery device 24 for the ink operated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet recording apparatus that performs recording by ejecting ink from a recording head onto a recording material.

[Conventional technology]

2. Description of the Related Art Recording devices such as printers, copying machines, and facsimile machines are configured to record images consisting of dot patterns on recording materials such as paper and thin plastic plates based on image information.

The recording device may be an inkjet type,
It can be divided into wire dot type, thermal type, laser beam type, etc. Among them, inkjet type (inkjet recording apparatus) is configured to perform recording by ejecting ink onto a recording material.

Inkjet recording apparatuses have advantages such as low noise because they are non-impact type, and the ability to easily record color images using multicolored inks.

However, since inkjet recording devices perform printing by directly ejecting ink from fine ejection orifices in the print head, the ejection orifices can become clogged with paper dust, dust, etc., resulting in ejection failure or even making recovery difficult. This may result in non-ejection.

Conventionally, measures have been taken to prevent ejection failure due to dust clogging of the ejection port, such as increasing the diameter of the ejection port or providing a mesh filter in the ink supply path.

[Technical problem to be solved by the invention] However,
The method of increasing the diameter of the ejection port results in a corresponding decrease in recording density, and therefore cannot be an essential countermeasure.

In addition, with the method of installing a mensch filter or the like in the ink supply path, even if it is possible to prevent foreign matter from entering from inside, there is a technical problem that if foreign matter enters from outside the ejection port, it becomes increasingly difficult to remove it. The present invention has been made in view of these technical problems, and when foreign matter such as dust becomes clogged in the discharge port, it can be quickly and reliably removed, and the discharge port is clogged. It is an object of the present invention to provide an inkjet recording device that can be efficiently recovered.

[Means for solving problems]

The present invention provides an inkjet recording apparatus that performs recording by discharging ink from a recording head onto a recording material, which is configured to include a fluid injection means for injecting fluid from an ejection port of the recording head into the recording head at a predetermined timing. As a result, when the ejection port is clogged with foreign matter such as dust, it is possible to quickly and reliably remove the foreign matter, thereby providing an inkjet recording apparatus that can efficiently recover from the ejection port clogging.

In the above configuration, if ink circulation means for circulating ink through the recording head is provided in addition to the fluid injection means, foreign matter pushed into the recording head can be quickly removed.

In the above configuration, by applying an ejection drive pulse to perform idle ejection after injecting the fluid, foreign matter pushed into the recording head can be quickly ejected from the ejection port.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the drawings.

FIG. 3 is a schematic perspective view illustrating the main part configuration of an inkjet recording apparatus to which the present invention is applied.

In FIG. 3, l is a head unit mounted on a carriage 3, and the head unit 1 includes a plurality of (four in the illustrated example) recording heads 2A, 2B, 2C, 2D.
have.

Each of the recording heads 2A to 2D has an ejection port (usually
A plurality of inks) are formed, and inks of different colors are ejected from the rads 2A to 2D to each recording.

For example, in the case of a color ink side recording apparatus, each of the recording heads 2A to 2D can be made to correspond to ink colors of yellow mine ink, cyan, and black, for example.

In FIG. 3, a carriage 3 on which the head unit 1 is mounted is movably supported along a guide rail 4, and a timing belt 5 is driven by a carriage drive motor 6.
It is driven reciprocally through the

A recording material 7 made of paper, a thin plastic plate, etc. is moved along a predetermined path at a predetermined timing and at a predetermined pitch by a pair of transport rollers 9 driven by a transport motor 8 and a pair of holding rollers 10 working together. The paper is transported (paper is fed) by

While this recording material 7 is held flat at the recording position facing the recording heads 2A to 2D, the recording material 7 is
Recording is performed while performing main scanning in ~2D, and when recording for one line is completed, the recording material 7 is pitch-fed in the direction of arrow f, and the next line is recorded.

The carriage 3 includes an ink supply tank 1 for supplying ink of a color corresponding to each recording head 2A to 2D.
3A to 13D are installed interchangeably.

Further, a home position H is set at a predetermined position within the movement range of the carriage 3 and outside the recording area, and a non-ejection recovery device 14 facing the recording heads 2A to 2D is disposed at the home position H. ing.

FIG. 4 is a perspective view schematically showing the plurality of recording rads 2A to 2D mounted on the carriage 3.

In FIGS. 3 and 4, each recording head 2A to 2D
An ink supply pipe 1 for supplying ink to the recording head is provided between the corresponding ink supply tanks 13A to 13D.
1 and an ink return pipe 12 for returning ink to the ink supply tank.

The non-ejection recovery bag N14 is movable back and forth, and when the carriage 3 reaches the home position H, moves forward to seal (cap) the ejection opening surfaces of the rads 2A to 2D for each recording.
Then, fluid is injected into the ejection port of each recording head (pressurized supply).
It is configured to suction and discharge ink from the ejection port as necessary, or to receive and receive ink that has not been ejected from the ejection port at the ejection port surface sealed position or the ejection port surface open position.

Example I: FIG. 1 is a schematic diagram showing a schematic configuration of a non-discharge recovery system of Example I of an inkjet recording apparatus according to the present invention.

FIG. 1 shows the recording head 2A at the home position H.
This shows a state in which the ejection port surface of 2D is sealed with the sealing member of the non-ejection recovery device 14, and the ejection ports 31 of the recording heads 2A to 2D are sealed.

Note that the recording head 2 and ink supply tank 13 in FIG. The head and any ink supply tank will be referred to as 2 and 13, respectively.

In FIG. 1, an ink supply tank 13 and a recording head 2
The liquid chamber 30 is connected to the ink supply pipe 11 and the ink return pipe 12, and a recovery pump 24 as an ink pressure feeding means is provided in the middle of the ink supply pipe 11.

A plurality of ejection ports 31 are formed on the ejection port surface (face surface) of the recording head 2, and each ejection port 31 connects to a respective liquid path 33.
It communicates with the liquid chamber 30 through.

An electrothermal converter (heating element) 32 is disposed inside each discharge port 31, that is, in each liquid path 33, along the wall surface thereof.

This electrothermal converter 32 generates heat when an ejection drive pulse (pulse voltage) is applied to impart ejection energy to the ink.

That is, the recording head 2 has a liquid path 33 in each ejection port 31.
An electrothermal converter 32 such as a heating element arranged along the
By applying a pulse voltage (ejection driving pulse) according to image information, the ink is brought to film boiling with thermal energy generated from the electrothermal converter, and the ink is ejected with the pressure at that time.

Therefore, each of the recording heads 2A to 2D is an inkjet recording head that discharges ink using thermal energy, and an electrothermal converter 32 for generating thermal energy is connected to a liquid path leading to each discharge port 31. 33.

Further, each of the recording disks 2A to 2D performs recording by ejecting ink from the ejection port 31 by the growth of bubbles due to film boiling caused by the thermal energy applied by the electrothermal converter 32.

A sealing member 16 is provided on the front surface of the ejection failure recovery device 14 and is in close contact with the periphery of the ejection port surface (the surface on which the ejection ports 31 are formed) of the recording head 2.
17 is formed.

Inside the cap 17, fluid discharge ports are provided for injecting fluid at a predetermined pressure from each discharge port 31 into the recording head 2 in a close contact state as shown in FIG.

As the fluid that is pressurized and injected (pushed) through the discharge port 31, for example, air, clear ink (desired liquid other than for recording), ink, or the like is used.

In this way, in an inkjet recording apparatus that performs recording by discharging ink from the recording pad 2 onto the recording material 7,
a fluid injection device that injects fluid (in this embodiment, air) into the recording pad 2 from the ejection port 31 of the recording head 2 at a predetermined timing; an ink circulation device that circulates ink through the recording pad 2; An inkjet recording apparatus is configured.

Next, a non-discharge recovery operation (operation for eliminating clogging of the discharge port 31) according to this embodiment will be described.

When the recording head 2 is in a position facing the non-ejection recovery device 14, after the non-ejection recovery device is pressed against the ejection port surface, strong compressed air is injected from the air outlet 18, and the air is removed from the ejection port. The liquid is injected so as to enter the recording head 2 from 31.

As shown in the figure, the air is injected at an injection angle that is parallel or nearly parallel to the discharge port 31, and foreign matter clogged in the discharge port 31 and the liquid path 33 is removed from the liquid chamber 30 by the air injection. being pushed back towards.

The fluid to be injected may be a desired liquid (such as clear ink) or ink (recording ink) in addition to the above-mentioned air.

After injecting air under pressure, by operating the ink pressure feeding means 24, the ink supply tank 13 → ink supply pipe 1 is
1 → Liquid chamber 30 → Ink return pipe 12 → Ink supply tank 1
The ink is circulated along the path No. 3.

Due to this ink circulation, the foreign matter pushed back into the recording pad 2 (liquid chamber 30) is either discharged together with the ink from the ejection port 31 at a different angle than when it was clogged in the liquid path 33, or the ink is returned It is discharged through tube 12.

In some cases, the ink circulation after the air injection described above may be omitted, and the non-ejection recovery operation may be completed simply by injecting a fluid such as air.

According to the embodiment described above, when ejection failure occurs due to clogging of the print head 2, fluid such as air is injected under pressure into the print head from outside the ejection port 31 along the liquid path 33. removes foreign matter clogged in the liquid path 33 etc. from the liquid chamber 30.
The foreign matter is pushed back into the RAD 2 for recording, and then the ink is circulated through the RAD 2 for recording to discharge the foreign matter, so conventional negative pressure suction recovery operation or empty discharge recovery operation cannot recover due to clogging. An inkjet recording device was obtained that can reliably recover the product even if ejection occurs.

Example 2: FIG. 2 is a schematic diagram showing a non-discharge recovery system of Example H of the inkjet recording apparatus according to the present invention.

In FIG. 2, a branch passage 19 is located in the middle of the ink return pipe 12.
is connected, and the other end of the branch path 19 is connected to a waste ink tank 36.
It is connected to the.

A circulation path pulp 34 is provided on the downstream side of the connection portion of the branch path 19 of the ink return pipe 12, and a branch path valve 35 is provided near the inlet of the branch path 19.

The configuration in Figure 2 differs from the configuration in Figure 1 in the above points, and the other parts are substantially the same as in Figure 1.
Corresponding parts are indicated by the same reference numerals, and detailed explanation thereof will be omitted.

In Example 3, air was injected through the discharge port 31, and then ink was circulated between the ink supply tank 13 and the ink.
In this embodiment, by providing a path 19 to the waste ink tank 36 in the middle of the ink return pipe 12, foreign matter is discharged into the waste ink tank 36 and disposed of during ink circulation.

That is, in FIG. 2, after the ejection failure recovery device 14 is brought into close contact with the recording head 2 and air (fluid) is injected into the recording head 2 from the ejection port 31, the circulation path valve 34 in the middle of the ink return pipe 12 is closed. At the same time, the branch valve 35 is opened, and the foreign matter is discharged together with the ink into the waste ink tank 36 during ink circulation, thereby disposing of the foreign matter.

When the non-discharge recovery operation is completed, the branch path valve 35 is closed and the circulation path valve 34 is opened to return to the original state.

In this embodiment, as in the case of Embodiment I, if ejection failure occurs due to clogging of the recording head 2, the ejection port 31
By injecting fluid such as air under pressure into the inside of the recording head along the liquid path 33 from the outside of the recording head 2, foreign objects clogged in the liquid path 33, etc. are pushed back into the inside of the recording head 2, such as the liquid chamber 30, and then the recording head 2.The ink is circulated through the interior and the foreign matter is discharged, so even if non-discharge occurs due to clogging, which is difficult to recover with conventional negative pressure suction recovery operation or empty discharge recovery operation, this can be easily and reliably fixed. A recoverable inkjet recording device was obtained.

Example (2): In the above-mentioned Examples (2) and (2), the foreign matter was discharged by ink circulation, but instead of this ink circulation, the foreign matter may be discharged by idle ejection in which the discharge is driven outside the recording area.

Therefore, in this embodiment, after air (fluid) is pressure-injected into the liquid chamber 30 from the ejection port 31 in the same way as described above, the foreign matter is ejected by performing dry ejection instead of ink circulation. Ru.

According to such a configuration, foreign matter such as dust that is clogged in the discharge port 31 or the liquid path 33 is first removed by the injected air (pressure fluid).
After that, the foreign matter is returned to the liquid chamber 30, and then, by performing idle ejection, the foreign matter causes a change in state, that is, a change in shape and angle, and is discharged to the outside from the ejection port 31 together with the ink.

According to this embodiment, as in the cases of Embodiments I and 2, it is possible to easily and reliably recover from clogging, which is difficult to recover with conventional negative pressure suction recovery operation or empty discharge recovery operation. Ta.

In each of the above embodiments, air is mainly used as the fluid injected into the recording pad 2 from the ejection port 31, but the injected fluid may be any desired liquid (such as clear ink). In addition to ink (for recording), various fluids can be used, such as desired gases other than air.

In the above embodiments, the present invention was explained by taking as an example a case in which the present invention is applied to a serial scan type inkjet recording apparatus in which the recording head 2 is mounted on the central ridge 3. The present invention can be similarly applied to inkjet recording devices using other recording methods, such as line-type inkjet recording devices that use a line-type recording head that covers the recording area in the paper width direction of the material, and similar effects can be achieved. It is something.

Further, in the above embodiment, a case of a color inkjet recording apparatus using four recording pads 2 was explained.
The present invention uses one recording head for monochromatic recording, or multiple recording heads with the same color but different densities! The present invention can be similarly applied to an inkjet recording device for Im recording, regardless of the number of recording heads, and can achieve similar effects.

The present invention brings about excellent effects particularly in an inkjet recording apparatus using an inkjet recording head of the bubble jet method proposed by Canon Co., Ltd. among inkjet recording methods.

As for typical configurations and principles thereof, it is preferable to use the basic principles disclosed in, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740,796.

This method can be applied to both the so-called on-demand type and the continuous type, but especially in the case of the on-demand type, it is necessary to place the liquid (ink) on the sheet or liquid path where it is held. By applying at least one drive signal that corresponds to recorded information and causes a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, the electrothermal transducer generates thermal energy, and the recording head This is effective because it causes film boiling on the heat acting surface of the liquid (ink), resulting in the formation of bubbles in the liquid (ink) in one-to-one correspondence with this drive signal.

Due to the growth and contraction of these bubbles, liquid (
ink) to form at least one droplet.

If this drive signal is in the form of a pulse, bubble growth and contraction will occur immediately and appropriately, so liquids with particularly excellent responsiveness (
As a more preferable pulse-shaped drive signal that can achieve ejection of ink, those described in US Pat. No. 4,463,359 and US Pat. No. 4,345,262 are suitable.

Further, if the conditions described in US Pat. No. 4,313,124 concerning the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be achieved.

The configuration of the recording head includes, in addition to the combined configuration of ejection ports, liquid paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, a heat acting section. US Pat. No. 4,558,333 and US Pat. No. 4,459,600 disclose a configuration in which the
The present invention also includes a configuration using the specification of the above specification.

In addition, Japanese Patent Application Laid-open No. 123670 of 1982 discloses a configuration in which a common slit is used as a discharge part for a plurality of electrothermal converters, and a hole that absorbs pressure waves of thermal energy is disclosed. The present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 138461 of 1981, which discloses a configuration in which a discharge portion corresponds to a discharge portion.

Furthermore, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length can be increased by combining multiple recording heads as disclosed in the above-mentioned specification. Either a configuration that satisfies the above requirements or a configuration as a single recording head formed integrally may be used, but the present invention can more effectively exhibit the above-mentioned effects.

In addition, a replaceable chip-type recording head that is attached to the device body enables electrical connection to the device body and ink supply from the device body, or a chip-type recording head that is installed integrally with the recording head itself. The present invention is also effective when a cartridge type recording head is used.

Further, it is preferable to add recovery means, preliminary auxiliary means, etc. for the recording head, which are provided as a configuration of the recording apparatus of the present invention, because the effects of the present invention can be further stabilized.

Specifically, these include a camping means, a cleaning means, a pressurizing or suction means, an electrothermal transducer or a separate heating element, or a preheating means for the recording head using a combination thereof. It is also effective to perform a preliminary ejection mode in which ejection is performed separately from printing in order to perform stable printing.

Furthermore, the recording mode of the recording device is not limited to a recording mode in which only the mainstream color such as black is used; the recording head may be configured integrally or in combination with a plurality of recording heads; The present invention is also extremely effective for devices equipped with at least one full color image.

In the embodiments of the present invention described above, the ink is explained as a liquid, but it is an ink that solidifies at room temperature or lower, and is softened or liquid at room temperature, or in the above-mentioned inkjet, the ink itself is heated at 30°C or higher. It is common to adjust the temperature within a range of 70°C or less so that the viscosity of the ink is within the stable ejection range.
Any ink may be used as long as the ink is in a liquid state when the recording signal is applied.

In addition, it is possible to proactively prevent temperature rise caused by thermal energy by using it as energy to transform the ink from a solid state to a liquid state, or to prevent ink from evaporating by preventing ink from solidifying when left unused. In any case, the ink may be liquefied by applying thermal energy in accordance with the recording signal and ejected as liquid ink, or it may already begin to solidify when it reaches the recording material. It is also applicable to the present invention to use ink that is liquefied only by thermal energy.

In such a case, as in Japanese Patent Application Laid-open No. 54-56847, the ink is held as a liquid or solid in the recesses or through holes of the porous sheet and is placed facing the electrothermal transducer. It may be in any form.

In the present invention, the most effective method for the above-mentioned ink is the one that implements the above-mentioned film boiling method.

(Effects of the Invention) As is clear from the above description, according to the present invention, in an inkjet recording apparatus that performs recording by discharging ink from a recording head onto a recording material, recording is performed from the ejection ports of the recording head at a predetermined timing. Since the recording head is configured to include a fluid injection means for injecting fluid into the head, if the ejection port becomes clogged with foreign matter such as dust, the foreign matter can be quickly and reliably removed by pushing the foreign matter back into the recording head. Provided is an inkjet recording device that can efficiently recover from clogging of ejection ports.

In addition to the above structure, in addition to the fluid injection means, an ink VIi ring means for circulating ink through the recording head may be provided, or after the fluid is injected, an ejection drive pulse may be applied to perform idle ejection. If configured to perform this, an inkjet recording apparatus is provided that can more quickly and reliably remove foreign matter pushed back into the recording head.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of main parts of an embodiment of an inkjet recording apparatus according to the present invention, Part 2 is a schematic diagram showing the composition of main parts of another embodiment of an inkjet recording apparatus according to the invention, and FIG. 4 is a schematic perspective view of an inkjet recording apparatus to which the present invention is applied, and FIG. 4 is a perspective view schematically showing the arrangement of the recording heads in FIG. 3. Below, symbols representing main components in the drawings are listed. 1--head unit, 2 (2A, 2B, 2C. 2D)--recording head, 3--carriage, 6--carriage drive motor, ? ------ Recorded material, 8-- Recorded material conveyance motor, 11--
Ink supply pipe, I2...-Ink return pipe, 13 (1
3A, 138113c, 13D) ---- Ink supply tank, 14 Non-discharge recovery device, 17 - Cap, ] 8 - Fluid discharge port, 19 - Branch path,
31--discharge port, 32--electrothermal converter, 33-
・-Liquid path, 34-...-Circulation path valve, 35-...
-・Diversion valve, 36-・Waste ink tank, H-・
−・−Home position.

Claims (7)

[Claims] (1) An inkjet recording apparatus that performs recording by discharging ink from a recording head onto a recording material is characterized by having a fluid injection means for injecting fluid into the recording head from an ejection port of the recording head at a predetermined timing. Inkjet recording device. (2) The inkjet recording apparatus according to claim 1, further comprising an ink circulation means for circulating ink through the recording head. (3) The inkjet recording apparatus according to claim 2, wherein the ink that has circulated within the recording head is guided to a waste ink tank separate from the ink supply tank. (4) The inkjet recording apparatus according to claim 1, wherein after injecting the fluid, an ejection drive pulse is applied to perform idle ejection. (5) The inkjet recording apparatus according to claim 1, wherein the fluid is air, ink, or a desired liquid. (6) A claim characterized in that the recording head is an inkjet recording head that ejects ink using thermal energy and is equipped with an electrothermal converter for generating thermal energy. Item 1. The inkjet recording device according to item 1. (7) The inkjet recording apparatus according to claim 6, wherein the recording head discharges the ink from the discharge port by the growth of bubbles due to film boiling caused by the thermal energy applied by the electrothermal converter. .