JP2013056518A - Liquid droplet discharge device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid droplet discharge apparatus that prevents a part thereof from getting dirty by an inadvertent dropping of ink reserved in a predetermined location due to the corrosion of the liquid droplet discharge surface when employing a recording head unit in which a liquid droplet discharge surface is arranged in a direction opposite to the direction of gravitational force, such as in an upward direction, and has a configuration for simple procedures by decreasing the frequency of replacement of the corroded liquid reservoir.SOLUTION: For a configuration in which a nozzle surface 105 of a recording head 7 mounted on a carriage 3 is arranged in an upward direction opposite to the direction of gravitational force, a reservoir part 101 having an opening on a surface flush with the nozzle surface 105, and a space with a depth along the direction of gravitational force includes a suction member 300 that is operable simultaneously with a capping member 160 that hermetically seals the nozzle surface 105, and sucks up liquid droplets entered and reserved therein and discharges the sucked liquid droplet into a waste liquid tank 220.

Description

  The present invention relates to a droplet discharge device and an image forming apparatus, and more particularly to a maintenance structure for a droplet discharge portion.

  As is well known, ink jet recording by a liquid discharge recording method using a recording head that discharges ink droplets in one of image forming apparatuses such as a printer, a facsimile machine, a copying machine, a plotter, or a multifunction machine having these functions. There is a device.

  This liquid ejection recording type ink jet recording apparatus ejects ink droplets from a recording head to a recording medium using a transported paper or the like (hereinafter, the recording medium may be expressed as a recording paper). Image formation (recording, printing, printing, and printing are also used synonymously) can be performed. As a model, there are a serial type that forms an image by ejecting droplets while the recording head moves in the main scanning direction, and a line type head that forms images by ejecting droplets without moving the recording head. There is a line type to use.

The liquid discharge recording type image forming apparatus according to the present invention forms an image by landing ink on a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics. Means a device to do.
In addition, image formation not only applies an image having a meaning such as a character or a graphic to a medium, but also applies an image having no meaning such as a pattern to the medium (simply landing a droplet on the medium). Meaning).

  Further, the ink used in the description of the present invention is not limited to what is referred to as ink, but can be used for image formation such as recording liquid, fixing processing liquid, resin, chemicals, and liquid. What is used as a general term for the liquids of

  In addition, the paper mentioned in the present invention is not limited to paper, but includes the above-described OHP sheet, cloth, and the like, and means that ink droplets adhere to the recording medium, recording medium, recording paper It is used as a generic term for what includes what is called recording paper.

As this liquid ejection method, the following method is known.
In other words, a part of the wall of the liquid chamber filled with ink is vibrated and displaced by a piezoelectric actuator or the like to increase the pressure in the liquid chamber and then discharge the ink.
As other methods, there is known a method in which a heating element that generates heat when energized is provided in the liquid chamber, and the pressure in the liquid chamber is increased by bubbles generated by the heat generation of the heating element to discharge ink.

  This type of ink jet recording apparatus is currently widely used because it has advantages such as high speed and low noise, few restrictions on the type of recording medium including recording paper, and easy colorization.

Here, the serial type and line type described above will be described in more detail as follows.
The serial type uses a carriage equipped with a droplet discharge head, serially scans the carriage in a direction perpendicular to the recording paper conveyance direction, and conveys the recording paper intermittently according to the recording width, thereby conveying and recording. (That is, droplet discharge) can be alternately repeated.

  The line type can use a line head in which droplet discharge nozzles are arranged corresponding to the entire area of one side of the recording paper. Since it only needs to be transported, the speed can be increased compared to the serial method.

  On the other hand, it is important to maintain and recover the performance of the recording head unit in order to stabilize the ink discharging operation from the recording head unit used as the above-described droplet discharging head. That is, it is desired to maintain a state in which residual ink due to dry solidification or the degree of adhesion does not adhere to the liquid discharge surface of the recording head unit, that is, the nozzle surface, so that liquid discharge is not hindered.

Therefore, a nozzle function maintenance / recovery device for maintaining and recovering the ink ejection function to a normal state has been proposed.
The functions set in the nozzle function maintenance / recovery device include a cap function that covers the nozzle surface with a moisturizing cap that provides high airtightness in order to suppress ink evaporation, and ejection using bubbles generated in the nozzle holes. There are a discharge recovery function that discharges defects by filling and feeding a recording liquid, and a wiping function that wipes off residual ink that adheres to the nozzle surface and causes the droplet flight state to change.

  The wiper blade used for wiping moves in a direction crossing the nozzle surface in order to wipe off ink adhering to the nozzle surface, and the ink adhering to the nozzle surface can be wiped away by this movement. .

  The ink wiped by the wiper blade is collected by the blade and absorbed by the absorber, or is collected and scraped off from the blade to be stored and discarded at one place.

  In the one-point recovery structure described above, a storage unit for collecting ink scraped by the wiper blade is provided adjacent to the base of the wiper blade in a part of the wiping unit including the wiper blade, and the inside of the storage unit is negatively charged. A configuration has been proposed in which ink in the reservoir is sucked by pressure (for example, Patent Document 1).

As disclosed in the above-mentioned Patent Document 1, the recording head unit has a configuration in which the nozzle surface is the upper surface of the recording medium, in other words, with the horizontal direction as a reference, and the wiper blade is downward. It is adapted to abut against the nozzle surface.
Accordingly, ink is ejected from the nozzle surface in the gravitational direction. However, when air bubbles are accumulated in the ink supply path on the recording head unit side, for example, excessive ink is contained in a sub tank provided for supplying ink. When the pressure is supplied, the pressure state that tends to be a negative pressure in the supply path except during discharge may change to a positive pressure tendency.
For this reason, there is a risk that the ink may inadvertently drip from the nozzle surface regardless of the ejection time. When the ink drips, the non-printing area of the transport section and the recording paper is soiled.

Therefore, in order to solve such a problem, there is a method for preventing the ink from dripping carelessly by setting the direction of the nozzle surface upward instead of downward.
When the nozzle surface is directed upward, the wiper blade and the storage portion or the absorbing member for storing ink wiped from the nozzle surface by the blade are disposed downward so as to face the nozzle surface. In particular, in the ink storage portion wiped by the wiper blade, the opening serving as the intake portion for the wiped ink faces downward.

When the opening of the storage part is downward, the ink stored in the storage part may flow to the nozzle surface side due to gravity.
Further, when the ink attached to the carriage used in the recording head unit becomes highly viscous and accumulates, the deposition amount becomes higher than the nozzle surface of the recording head. When the carriage moves in this state, the accumulated ink may come into contact with the recording medium and contaminate the recording medium.

On the other hand, when the ink wiped by the wiper blade is absorbed, the ink can be collected regardless of the orientation of the nozzle surface, but it takes up a large installation space because it is arranged in the vicinity of the recording head and the wiper blade. I can't.
For this reason, the volume of the absorbing member is also reduced, and there is a limit to the storage capacity that can be absorbed. As a result, not only does it take time and effort to be replaced over time, but the user cannot easily perform replacement work during replacement due to problems such as installation space.

  In view of the problems in the conventional droplet discharge device, the object of the present invention is wiped from the droplet discharge surface when using a recording head unit in which the droplet discharge surface is disposed in the direction opposite to the gravity direction such as upward. In addition to preventing the ink from being stored at a predetermined location from dripping inadvertently, it is possible to simplify the work procedure by reducing the frequency of replacement of the storage portion of the wiped liquid droplets. It is to provide a droplet discharge device.

  In order to achieve this object, the present invention provides a recording head having a nozzle surface capable of ejecting droplets with the droplets directed upward, and supports the recording head movably along the surface of a recording medium such as recording paper. Nozzle function maintaining / recovering means comprising: a holding member that moves; a wiping member that can move in a direction to wipe the nozzle surface facing the nozzle surface; and a capping member that can seal the nozzle surface facing the nozzle surface A storage portion having an opening adjacent to the nozzle surface of the holding member, and having a space for storing droplets scraped from the nozzle surface by the wiping member, and provided in the wiping member for the storage. A suction member capable of advancing and retreating with respect to the inside of the unit, and the wiping member is set in a direction of wiping in a direction of passing through the nozzle surface and reaching the storage unit, and the suction member is disposed in the storage unit. Enter In a droplet discharge device, characterized in that the discharge from the reservoir to suck a droplet, which is stored.

According to the present invention, the storage unit for storing the liquid droplets scraped off by the wiping member is provided adjacent to the nozzle surface capable of discharging the liquid droplets upward, so that the liquid droplets are scraped from the upward nozzle surface. The droplets can be introduced into the reservoir using the fact that they fall in the direction of gravity.
Moreover, since the storage portion is provided with a suction member that can suck the liquid droplets that have entered and stored therein, the liquid droplets scraped off by the wiping member thereby reattach to the nozzle surface. It is prevented.
As a result, unlike the case of using a member with limited capacity, such as an absorbing member, the structure for preventing reattachment to the nozzle surface eliminates the need for maintenance such as component replacement and the vicinity of the nozzle surface and nozzle surface. It is possible to reliably prevent contamination on the slipping surface or its peripheral portion by preventing inadvertent reattachment of droplets to the portion.

1 is a diagram for explaining an embodiment of an image forming apparatus. FIG. 2 is a view showing a droplet discharge device used in the image forming apparatus shown in FIG. 1 from the bottom side of the apparatus. FIG. 2 is a diagram for explaining a wiping mechanism used in a nozzle function maintenance / recovery device of a droplet discharge device equipped in the image forming apparatus shown in FIG. 1. It is a figure for demonstrating the capping mechanism and droplet suction mechanism which are used for the nozzle function maintenance recovery apparatus of the droplet discharge apparatus shown in FIG. It is a figure for demonstrating another Example regarding the capping mechanism and droplet suction mechanism shown in FIG. It is a figure for demonstrating the modification regarding the capping mechanism and droplet suction mechanism shown in FIG. It is a figure for demonstrating another Example regarding the droplet suction mechanism shown in FIG. It is a figure for demonstrating another Example of the wiping mechanism shown in FIG. It is a figure for demonstrating the other Example regarding the droplet suction mechanism shown in FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to illustrated embodiments.
FIG. 1 shows a droplet discharge recording apparatus, which is one of image forming apparatuses according to an embodiment of the present invention, that is, printing by causing droplets to land on a sheet S which is one of so-called recording media. 1 shows an ink jet recording apparatus.

In FIG. 1, the ink jet recording apparatus 100 includes the following apparatuses.
That is, the recording head unit 7 that is mounted on the carriage 3 as the holding unit that is slidably supported by the rods 90 and 91 and is used as the image forming unit, and the conveyance belt 21 that conveys the recording sheet that is used as the recording medium. A sheet feeding apparatus 10 having a sheet feeding cassette 11 in which recording sheets 12 are stacked and stored, a sheet discharge tray 54 from which printed recording sheets are discharged, and a nozzle function maintenance and recovery apparatus 500 (see FIG. 2). ing.

The carriage 3 is a main member of the droplet discharge device, and as shown in FIG. 2, the recording paper 12 is fed by a timing belt 5 stretched between a driving roller 6a and a driven roller 6b driven by a main scanning motor 4. Printing is performed by ejecting ink droplets from the nozzle surface while performing serial scanning in a direction perpendicular to the transport direction.
A recording head 7 having a nozzle surface for discharging droplets of a plurality of colors such as yellow (Y), cyan (C), magenta (M), and black (Bk), that is, ink droplets, is main-scanned on the carriage 3. It is arranged along the direction.

  A plurality of nozzle surfaces of the recording head 7 are arranged in a direction orthogonal to the main scanning direction, and in this embodiment, the nozzle surfaces are arranged in the direction facing the gravitational direction with the nozzle surface facing upward, as shown in FIG. It faces the lower surface of the recording paper.

As the recording head 7 used in the present embodiment, a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes film boiling of a liquid using an electrothermal transducer such as a heating resistor, and a shape that uses a metal phase change due to a temperature change. A storage alloy actuator, an electrostatic actuator using an electrostatic force, or the like provided as energy generating means for discharging ink (recording liquid) can be used.
The carriage 3 is equipped with sub-tanks (not shown) for each color for supplying ink of each color to the recording head 7. This sub tank is constructed integrally with the recording head 7 so that ink is replenished and supplied to the sub tank from an unshown main tank (ink cartridge) via an ink supply tube.

On the other hand, since the nozzle surface provided on the carriage 3 is liable to cause nozzle clogging due to drying, the carriage 3 is in operation even during non-printing such as when the machine is stopped due to an error during printing or when the power is turned off. It is designed to be moisturized by being sealed with a cap 160 when not present.
For this reason, the carriage 3 faces the nozzle function maintenance / recovery device 500 disposed on the side in the width direction of the transport belt 21 in addition to the movement in the main scanning direction with respect to the recording paper 12 at the time of printing. Move to the position.

As shown in FIG. 2, the nozzle function maintenance / recovery device 500 includes a cap 160 that is a number of capping members corresponding to the nozzle surface of the recording head 7, and is a wiping member that can move in the direction of wiping the nozzle surface. A wiper blade 150 is provided.
The nozzle function maintenance / recovery device 500 moves toward the nozzle surface using a slider in the insulator city in conjunction with the movement of the carriage 3 to a position facing this (for convenience, it may be expressed as a standby position). The cap 160 seals the nozzle surface of each color. The internal space of the cap 160 is made negative pressure so that bubbles in the nozzle surface can be discharged.

  On the other hand, the wiper blade 150 is a member that can move in a direction in which the nozzle surface can be wiped, and is used as a member that forms a meniscus on the nozzle surface by wiping ink droplets adhering to the nozzle surface.

  In the paper feeding device 10 described above, the printing paper 12 loaded in the paper feeding cassette 11 is separated and fed out one by one by the cooperation of the feeding roller 13 and the separation pad 14 made of a high friction coefficient member that contacts and faces the feeding roller 13. It is.

  The recording paper 12 fed out from the paper feed cassette 1 passes through the paper guide 15, and then passes through the paper presence / absence detection sensor 200 using a reflection type optical sensor, and is conveyed toward the conveyance belt 21.

The conveyor belt 21 is an endless belt that is wound between a conveyor roller 27 and a tension roller 28 so that the surface of the conveyor belt 21 is charged by a charging roller 26 that is in contact with the surface, and the recording paper can be conveyed while being electrostatically attracted. It has become.
The rotation of the conveyance belt 21 is performed by transmitting rotation from the sub-scanning motor 31 to the conveyance roller 27 via the timing belt 32, and the rotation control is provided on the tension roller 28 side as shown in FIG. Control is based on a detection signal of a rotation detection sensor 36 using the encoder 34 and the optical sensor 35.

The features of the present embodiment will be described below for the inkjet recording apparatus 100 having the above configuration.
In the present embodiment, an opening is provided on the same side as the nozzle surface adjacent to the recording head 7 in which the nozzle surface is disposed upward, and ink droplets from the nozzle surface wiped by the wiper blade 150 can be stored. The storage unit 101 is provided, and the ink droplets stored in the storage unit 101 are sucked and discharged.

Hereinafter, this configuration will be described.
FIG. 3 is a diagram showing an arrangement configuration of the carriage 3 and the recording head 7 shown in FIG. 1, in which the nozzle surface 105 corresponding to the liquid ejection in the recording head 7 is arranged upward facing the direction of gravity. Has been.

As shown in FIG. 3A, a cross-sectional shape having an opening in the same direction as the nozzle surface 105 is concave at a position corresponding to the downstream side in the wiping direction of the wiper blade 150 at a position adjacent to the side of the recording head 7. The storage part 101 which consists of these spaces is provided.
In FIG. 3, the reservoir 101 is positioned so that the opening in the height direction of the carriage 3 is substantially the same height as the nozzle surface of the recording head 7. As a result, there is no step in the process of moving the wiper blade 150, so that it is possible to prevent ink droplets that have been wiped off from the stepped portion from accumulating and prevent ink droplets from remaining on the nozzle surface.

  The wiper blade 150 is made of a flexible elastic body to enhance the adhesion to the nozzle surface, has a size that can cover the entire area of the nozzle surface, and is in the direction indicated by the arrow in FIG. In the process of moving, the ink droplets 110 adhering to the nozzle surface 105 are wiped off. Further, the wiper blade 150 is set to a movement amount that can pass through the opening of the storage unit 101 (a movement amount that provides the state shown in FIG. 3C) as the movement amount in the direction indicated by the arrow.

FIG. 3B shows a state where the wiper blade 150 has finished moving on the nozzle surface 105.
The ink 110 collected at the tip of the blade by the wiping operation of the wiper blade 150 is stored in the storage hole 110 provided integrally with the carriage 3. At this time, the end of the storage hole 110 is formed on substantially the same plane as the droplet discharge surface 105, and the ink 110 can be easily stored in the storage hole 101.

FIG. 3C shows a state where the wiper blade 150 drops the ink 110 into the storage hole 101 and is separated from the storage hole 100.
The ink 110 attached when the wiper blade 150 wipes the droplet discharge surface 105 falls and is stored in the storage unit 101 from the opening of the storage hole 101, and further, the movement of the wiper blade 150 at the opening of the storage hole 101 is performed. The ink adhering to the surface of the wiper blade 150 is removed by the edge on the downstream side in the direction. Thereby, even if a restoring force is generated in the wiper blade 150 in a bent state, the ink does not scatter in the recording apparatus.
The shape of the storage hole 101 may be any shape such as a square or a circle. However, since the wiper blade 150 after wiping the nozzle surface 105 can be effectively cleaned, it is desirable to avoid the circle. It is desirable that a plane parallel to the width direction corresponding to a direction perpendicular to the 150 moving direction is formed.
Further, the installation position of the storage unit 101 with respect to the recording head 7 is not only a position adjacent to the nozzle surface in the sub-scanning direction of the recording head 7 but also a position adjacent to the nozzle surface in the main scanning direction of the recording head 7. It is also possible to do.

In the configuration as described above, when a configuration in which the nozzle surface is arranged upward is targeted, the ink droplets wiped by the wiper blade 150 and scraped off from the nozzle surface are transferred from the wiper blade 150 to the storage unit 101. Therefore, the ink droplet does not drop when it remains attached to the wiper blade 150.
As a result, the occurrence of contamination on the nozzle surface and the vicinity of the nozzle surface due to reattachment to the nozzle surface due to the fall of the wiped ink droplet is eliminated.

On the other hand, FIG. 4 is a diagram showing a configuration for sucking and discharging ink droplets accumulated in the storage unit 101, which is one of the features described above.
In FIG. 4, a cap 160 is supported by a cap holder 210 and is supported in a state where adhesion to the nozzle surface is improved by correcting a biasing spring 210 disposed between them.

  The cap holder 210 is a member that can be fitted and slid into a guide member 212 that guides the cap 160 toward the nozzle surface. The guide hole 225 formed in a part of the guide member 212 includes a cap holder 210 and a cap holder 210. The integrated suction member holder 223 is inserted.

  The suction member holder 223 has a suction port 300 supported by a portion projecting outward from a guide hole 225 formed in the guide member 212, and the suction port 300 is connected to the suction member holder 223 in conjunction with the cap holder 221. Accordingly, the front end facing the storage unit 101 can be advanced and retracted into the storage unit 101.

The cap holder 210 uses an elliptical cam 211 and a cam follower 230 provided on the cap holder 210 side as a drive unit mechanism for sealing and capping the nozzle surface.
The cam follower 230 slides the cap holder 210 within the guide member 212 in accordance with the rotation of the cam 211, and in conjunction with this sliding, the cap 160 is brought into contact with or separated from the nozzle surface, and the suction member holder 223 is also the same. Move in the direction.

Thereby, when the cap holder 210 moves in the direction in which the cap 160 is brought into close contact with the nozzle surface, the suction member holder 223 also moves in the same direction, so that the suction port 300 can enter the storage unit 101.
The moving stroke for causing the suction port 300 to enter the storage unit 101 is preferably a moving stroke that allows the suction port 300 to be closest to the bottom while avoiding the collision of the suction port 300 with the bottom of the storage unit 101. The amount setting is set by the cam profile of the cam 211. The length of the suction port 300 is also set based on the above-described conditions according to the movement stroke. As a result, it is possible to suck even a small amount of ink droplets accumulated in the storage unit 101.

A pump 222 serving as a suction source communicates with the suction port 300 via a pipe 215 that forms a flow path for sucking ink droplets stored in the storage unit 101, and the pump 222 is connected via the pipe 216. It is connected to the waste liquid tank 220.
The inside of the waste liquid tank 220 is filled with a large capacity absorber. This reduces the frequency of replacement due to long-term use of the ink jet recording apparatus, and improves the workability of replacement by allowing work to be performed at a position different from the limited space in the ink jet recording apparatus during replacement. ing.

  The pump 222 that is a suction source is a tube pump such as a tube pump that reliably generates a negative pressure even when there is no ink when driven.

Since the present embodiment is configured as described above, when the ink 110 is collected in the storage unit 101 by the wiper blade, it is transferred to the waste liquid tank 220 by the suction port 300 provided at a position facing the storage unit 101.
That is, as shown in FIG. 3A, when the cam follower 230 is positioned on the short axis side of the cam 211, the cap holder 210 is raised and the cap 160 is separated from the recording head 7. In this state, the suction member holder 223 is also detached from the storage unit 101 in conjunction with the cap holder 210.

  When the cam follower 230 is positioned on the long axis side of the cam 211, the cap holder 210 is lowered as shown in FIG. When the cap holder 210 is lowered, the cap 160 comes into close contact with the nozzle surface of the recording head 7 to seal the nozzle surface, and the suction member holder 223 is also lowered to cause the suction port 300 to enter the storage unit 101. At this time, by driving the pump 222, the ink droplets accumulated in the storage unit 1010 are sucked and discharged toward the waste liquid tank 220.

  In the above configuration, ink droplets accumulated in the storage unit 101 from the nozzle surface by wiping the wiper blade 150 as a wiping member on the nozzle surface of the recording head 7 arranged upward are wiped off the wiper blade 150. Since suction is performed by the suction port 300 that continuously enters the storage unit 101, ink droplets can be removed from the nozzle surface over a long period of time without using a component that has a use limit such as an absorber. As a result, maintenance work such as component replacement can be eliminated.

The configuration of the suction port 300 is preferably based on the following conditions.
If the inner diameter of the suction port 300 is too small, the resistance when ink flows through the suction port is increased. Therefore, it is necessary to set the inner diameter so that the ink can be carried to the waste liquid tank with a negative pressure that can be generated by the suction pump. is there.
In addition, the cap holder 210 and the supply port holder 223 are configured to operate integrally, but the cap holder 210 and the supply port holder 223 may be configured to operate independently. Further, if the size of the tip of the suction port 300 is too close to the size of the hole of the storage unit 101, when the suction port 300 is inserted into the storage unit 101, there is no air leak path in the storage hole, and the storage unit The pressure in 101 increases. Therefore, the suction port 300 is not normally inserted into the storage unit 101. In order to prevent this, it is desirable that the tip of the suction port 300 is sufficiently smaller than the size of the hole in the reservoir 101.
The suction member holder 223 is not limited to being integrated with the cap holder 210, and may be configured to operate independently.

Next, another embodiment relating to the droplet discharge device will be described with reference to FIG.
The embodiment shown in FIG. 5 is characterized in that the ink suction operation of the cap 160 and the suction port 300 is used in combination by driving one suction pump 222.
5A shows a tube 215 constituting a flow path communicating with the internal space of the cap 160 with respect to the suction pump 222, and a tube constituting a flow path communicating with the suction port 300 that can enter the storage portion 101. FIG. 217 is connected.
In this figure, a switching mechanism 299 that connects only one flow path is connected to each of the tubes 215 and 217.

When one suction pump 222 uses both cap suction and suction from the suction port 300, if one of them is connected to the atmosphere, the suction pump 222 sucks air from the atmosphere. Become. That is, the suction function cannot be achieved.
Therefore, when either one performs the suction operation by the switching mechanism 299, the other flow path is closed and blocked from the atmosphere.

In the switching mechanism 299 shown in FIG. 5, a mechanism is used in which one of the flow paths is communicated and the other is closed.
FIG. 5B shows the configuration in this case. In FIG. 5B, the switching mechanism 299 shows a case where an electromagnetic valve 260 is used as a driving source for opening and closing each flow path.

In FIG. 4B, the tube 215 side is in an open state, and the tube 217 is in a closed state. In the tube 215, the valve body 255 in the electromagnetic valve 260 is separated from the displacement part 270, and the flow path is opened. On the other hand, in the tube 217, the valve body 255 pushes the displacement part 270, and interrupts | blocks a flow path. In the figure, reference numeral 277 denotes an opening urging member such as a spring. When pressed by the valve body 255, the spring wires are brought into close contact with each other to close the tube 215, and the valve body 255 is electromagnetic. When sucked by the valve 260, the interval between the spring wires is widened to open the tube 215.
When the tube 215 is closed and the tube 217 is communicated, the operation of the valve body 255 may be reversed from that when the tube 215 is opened.

With such a configuration, for example, when the ink 110 is collected in the storage unit 101 and the ink 110 is sucked by the suction port 300, the electromagnetic valve 240 in the tube 215 is opened and the electromagnetic wave in the tube 217 is opened. The valve 241 is closed. By driving the suction pump 222 in this state, the ink 110 can be transferred to the waste liquid tank.
It is desirable that the displacement portions 270 and 270 ′ in the tubes 215 and 218 are made of a material that is flexible and can be deformed unevenly in order to smoothly perform the switching operation of the open / close state.

  Further, the state of the carriage 3 shown in FIG. 5 shows an example of the state in which the nozzle surface 105 of the recording head 7 is arranged upward and faces the direction of gravity, similarly to the case shown in FIG. The nozzle surface 105 is not limited to be positioned in the horizontal direction, and if the nozzle surface 105 faces upward, the storage unit 101 and the suction mechanism described above can be used for this state.

Next, another embodiment relating to the configuration for switching the open / close state of the flow path shown in FIG. 5 will be described with reference to FIG.
The configuration shown in FIG. 6 is characterized in that a convex sealing portion 320 that can make the tip of the suction port 300 is provided to switch the open / close state between the tubes 215 and 217 constituting the flow path.
As shown in FIG. 6A, the carriage 3 is provided with the nozzle surface 105 of the recording head 7 facing upward, and a tube 215 communicating with the suction port 300 and a tube communicating with the internal space of the cap 160. Each of the 217 is connected to the suction pump 222.
As shown in FIG. 6B, the bottom of the storage part 101 into which the suction port 300 enters, as shown in FIG. 6B, a sealing part 320 made of a convex part having a triangular cross section that can have a centering function with the suction port 300. Is provided.
The tip opening of the suction port 300 has a cone shape with an enlarged diameter so as to correspond to the shape of the sealing portion 320.

In this embodiment, the switching mechanism 299 shown in FIG. 5A does not exist, but the open / close state of the tubes 215 and 217 is switched by providing the sealing portion 320 having the above-described configuration. ing.
FIG. 6C shows a state where the ink 110 is stored in the storage unit 101 and the suction port 300 is further inserted into the storage unit 101. At this time, the cap 160 caps the droplet discharge surface 105. When the suction pump 222 is driven in this state, since the cap 160 is blocked by the droplet discharge surface 105, the ink in the storage unit 101 is carried from the suction port 300 to the waste liquid tank 220.

  Thereafter, when the cap 160 further bites into the droplet discharge surface 105 side, the suction port 300 moves toward the bottom of the storage unit 101 as shown in FIG. At this time, the opening of the suction port 300 is sealed with the sealing part 320. When the suction pump 222 is driven in this state, since the opening of the suction port 300 is closed by the sealing portion 320, the ink that has passed through the droplet discharge surface 105 is carried from the cap 160 to the waste liquid tank 220. The nozzles arranged on the droplet discharge surface 105 can be cleaned.

As described above, by disposing the sealing portion 320 at the bottom of the storage portion 101 and closing the suction port by the sealing portion 320, the ink can be discharged from the storage portion 101 without using a switching mechanism. Ink can be selectively discharged from the cap 160.
In the present embodiment, the cap 160 and the suction port 300 operate as one body, but a configuration in which each of them operates independently is also applicable. In that case, it is not necessary to further bite the cap 160 toward the droplet discharge surface 105 in a state where the cap 160 has capped the droplet discharge surface 105, and only the suction port 300 is sealed with the sealing portion 320 while maintaining the capping operation. The opening may be sealed by moving in the direction.

Next, another embodiment relating to the storage section will be described with reference to FIGS.
The storage section shown in FIGS. 7 and 8 (indicated by reference numeral 101 ′ for convenience) is characterized by the shape of the inner wall surface from the opening to the bottom of the space.
That is, in the embodiment shown in FIGS. 3 to 6, the liquid level of the collected ink 110 is low because the area of the bottom of the reservoir 101 is relatively large.
Therefore, in order for the suction port 300 to suck out the ink 110 in the storage unit 101 ′, it is necessary to repeat the wiping operation so that the ink 110 is stored in the storage unit 101 ′ to some extent. However, since the amount of ink stored in the storage unit 101 ′ by a single wiping is small, it takes time to reach a liquid level that can suck the ink 110 in the storage unit 101. There is a risk that the ink will thicken over time. In addition, when the viscosity of the ink is increased, there is a possibility that even if the suction pump 222 is driven and the ink 110 is discharged from the suction port 300, the fluid resistance is high and the suction cannot be performed.

Therefore, in the present embodiment, in a space having a depth along the direction of gravity from the opening in the reservoir 101 ′, the cross-sectional area between the inner wall surfaces from the opening on the side facing the suction port 300 to the space bottom becomes small. Thus, as shown in FIG. 6, the cross-sectional shape in the depth direction forms a space that is recessed so that the bottom side becomes narrow along the direction of gravity, and the area in which the ink droplets 110 are stored is reduced. It was.
With such a configuration, even when the number of wiping operations is small, the liquid level of the ink 110 that wipes the nozzle surface 105 can be increased. Accordingly, it is possible to discharge the ink 110 from the storage unit 101 ′ in a state where time has not passed after wiping. Note that. The shape of the sealing portion 320 provided at the bottom of the storage portion 101 ′ is preferably a shape that easily fits into the opening of the suction port 300, and may be, for example, a hemispherical shape as illustrated.

  On the other hand, in the embodiment shown in FIG. 8, in order to reduce the area at the bottom of the reservoir 101 ′ as in the case shown in FIG. 7, the inner side surface from the opening to the bottom of the space (the surface indicated by γ in the figure). ) Is inclined along the direction of gravity so that the bottom of the space becomes narrow, and is formed in a tapered shape when viewed from a direction perpendicular to the direction of movement of the wiper blade 150.

In such a configuration, when the nozzle surface 105 is wiped by the wiper blade 150, the ink droplets 110 attached to the nozzle surface 105 are scraped off toward the storage portion 101 ′ (see FIG. 8A). .
When the wiping of the nozzle surface 105 is completed and the wiper blade 150 reaches the storage portion 101 ′, the ink droplet 110 wiped by the wiper blade 150 flows along the inner surface of the storage portion 101 ′ toward the bottom of the space.

  When the water repellent treatment (indicated by reference numeral 400 in FIG. 8C) is applied to the inner wall surface or the inner side surface where the ink droplets wiped off in the storage unit 101 ′ flow down, the ink droplets wiped by the wiper blade 150 110 moves to the bottom of the reservoir 101 ′ without stagnation on the inclined surface 400. Thereby, the ink 110 thickens and adheres to the inside of the storage portion 101 ′, and the discharge of the ink 110 from the hole bottom by the suction port can be prevented. Note that the inclination angle of the inclined surface 400 is desirably an angle at which the ink 110 can be moved to the center of the space bottom of the storage unit 101.

On the other hand, in this embodiment, a device for preventing ink droplets from remaining on the suction port 300 is also employed, and the configuration and the reason for this configuration will be described with reference to FIG.
That is, if the sucked ink remains attached to the inside of the suction port 300, the fluid resistance rapidly increases due to thickening of the ink.
If the ink jet recording apparatus is continuously used as it is, there is a possibility that the ink is clogged inside the suction port 300 and the suction operation cannot be performed.

In order to prevent this, it can be dealt with by increasing the inner diameter of the suction port 300, but if the suction port 300 is made larger in diameter, the hole of the storage part 101 also becomes larger.
When the storage unit 101 becomes large, the carriage 3 becomes large, and the load on the drive motor increases when scanning during printing.

In view of such technical problems, in this embodiment, the inner diameter of the suction port 300 is not increased, and the ink in the suction port 300 is removed before the ink thickens.
Hereinafter, this configuration will be described.
In FIG. 8, the suction pump 222 is configured such that the built-in roller can rotate forward and backward (in the state indicated by reference numerals R1 and R2 in the figure), and the inside of the tube 215 is made negative pressure or positive depending on the rotation direction. It can be compressed.

In the above configuration, after the suction pump 222 is driven in the R2 direction to perform the suction operation in the waste liquid tank 220 direction, the ink in the suction port 300 is discharged by rotating in the reverse direction in the R1 direction (indicated by an arrow in the figure). (Shown state) The operation is performed.
By this operation, ink is not left inside the suction port 300, and the ink discharge operation from the suction port 300 can be realized for a long time.
When performing reverse rotation, it is desirable to retract the opening of the suction port 300 from the nozzle surface side in order to prevent ink ejected from the suction port 300 from adhering to the nozzle surface 105 of the recording head 7. .

DESCRIPTION OF SYMBOLS 3 Carriage 7 Recording head 100 Inkjet recording device 105 Nozzle surface 101, 101 'Reserving part 110 Ink droplet 150 Wiper blade 160 Cap 215, 217 Tube 222 Waste liquid tank 222 Suction pump 255 Valve body 260 Electromagnetic valve 270, 270' Displacement of tube Part 299 switching mechanism 400 water repellent treatment part

JP 2009-172952 A

Claims (10)

A recording head provided with a nozzle surface capable of discharging the liquid droplets upward,
A holding member for supporting the recording head movably along the surface of a recording medium such as recording paper;
A nozzle function maintaining / recovering means comprising a wiping member that can move in the direction of wiping the nozzle surface facing the nozzle surface, and a capping member that can seal the nozzle surface facing the nozzle surface;
A storage portion having an opening adjacent to the nozzle surface of the holding member, and having a space for storing liquid droplets scraped from the nozzle surface by the wiping member;
A suction member provided on the wiping member and capable of advancing and retracting with respect to the inside of the storage portion;
The wiping member is set in the direction of wiping in the direction of passing through the nozzle surface and reaching the reservoir,
When the suction member is connected to a suction source and enters the storage section, the suction member sucks the stored liquid droplets and discharges them from the storage section.   The suction member is provided with a flow channel capable of communicating with the internal space of the capping member in addition to a flow channel capable of entering the storage portion, and each of the flow channels can be switched between a communication state with a suction source. The droplet discharge device according to claim 1, wherein the droplet discharge device is connected to a simple flow path switching mechanism.   The suction member is provided with a flow path that can communicate with the internal space of the capping member in addition to a flow path that can enter the storage portion, and each of the flow paths is connected to a suction source, and Of the paths, a flow path that can enter the storage section is provided with a closed section that can close the flow path as the amount of entry into the storage section increases, and the closed section can enter the storage section. 2. The droplet discharge device according to claim 1, wherein when a simple flow path is closed, only the flow path communicating with the inside of the capping member maintains a communication state with the suction source.   The storage portion is configured by a space having a depth along the direction of gravity on the nozzle surface side, and the cross-sectional area between the inner surfaces is reduced in the space from the opening to the space bottom. The droplet discharge device according to claim 1.   5. The liquid according to claim 4, wherein in the storage portion, the inner side surfaces are inclined along the direction of gravity so that a cross-sectional area of an inner wall surface from the opening to the bottom of the space is reduced in the space. Drop ejection device.   The liquid droplet ejection device according to claim 5 or 6, wherein a water repellent finish is applied to an inner wall surface of the space in the storage section.   4. The droplet discharge device according to claim 1, wherein the suction source is capable of driving control capable of generating a positive / negative pressure. 5.   2. The liquid according to claim 1, wherein the capping member and the suction member are integrated, and the suction member enters the storage portion in conjunction with the capping member sealing the sliding surface. Drop ejection device.   The droplet discharge device according to claim 1, wherein the opening of the reservoir and the nozzle surface are arranged on the same plane.   A droplet discharge device having a recording head having a plurality of nozzle surfaces, and performing a printing operation for discharging droplets from the nozzle surfaces while the recording head moves in a direction perpendicular to the conveyance direction of the recording medium An image forming apparatus using the droplet discharge device according to claim 1 as the droplet discharge device.

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