JP2003053989A - Ink tank, ink jet print head using it and printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink tank exhibiting high durability even when it is filled with ink repeatedly and having such a structure as exhibiting excellent ink use efficiency without having any effect on the ejection performance of a print head. SOLUTION: A negative pressure generating member deforming depending on the displacement or deformation of a movable section (106) which displaces or deforms depending on the quantity of ink being contained and bringing about a negative pressure state between ink containing spaces by urging the movable section is provided in the ink tank. The negative pressure generating member is a pair of leaf springs (107) having substantially U-shape combined by engaging the opposite end parts with each other while facing the open side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink tank, an inkjet printhead using the ink tank, and a printing apparatus.

[0002]

2. Description of the Related Art In an inkjet printing apparatus that forms an image on a print medium by applying ink to the print medium using the ink jet print head, the print head is moved relative to the print medium and ink is ejected in the process. There is a method for forming an image by performing the above, and a method for forming an image by ejecting ink in the process while moving the print medium with respect to a fixed print head, on the contrary.

As a method of supplying ink to a print head applied to such an ink jet printing apparatus, a supply system is provided so that an amount of ink corresponding to the ejected ink amount is always continuously supplied to the print head. There is a system configured as follows (hereinafter referred to as a continuous supply system). Then, for example, it is applied to an inkjet printing apparatus of a so-called serial type in which a print head reciprocally scans a print medium in a predetermined direction and the print medium is conveyed in a direction substantially orthogonal to the print medium to form an image. The continuous supply method includes an on-carriage method in which an ink tank is inseparably or separably attached to a print head mounted on a carriage or the like and reciprocally moved (main scanning) to supply ink. In addition, an ink tank is fixedly installed in another part of the printing apparatus separately from the print head mounted on the carriage, and the ink tank and the print head are connected via a flexible tube to transfer ink. There is also a so-called tube supply system for supplying, but this also includes a form in which a second ink tank that functions as an intermediate tank between the ink tank and the print head is mounted on the print head or carriage. .

Further, as another ink supply system, a print head is provided with a storage portion (sub-tank or second ink tank) for storing a predetermined amount of ink, and an ink supply source (main tank or second tank) is supplied to the storage portion. 1
There is also a system (hereinafter, referred to as an intermittent supply system) in which a supply system is configured to supply ink intermittently at appropriate timing from an ink tank.

In these systems, when an ink tank for directly supplying ink to the print head is used,
While the ink tank has a movable portion that can be displaced or deformed according to the amount of ink stored, in the ink tank,
A configuration is known in which a spring member is provided that generates a negative pressure in a range in which the ink ejection operation of the print head is balanced with the holding force of the meniscus formed in the ink ejection portion of the print head.

As a form of such a spring, a coil spring and a leaf spring are mainly mentioned. Regarding the coil spring, the coils overlap when the movable portion is deformed and closed and compressed according to ink consumption, and the coil wire diameter x Since the thickness corresponding to the number of windings is generated, the dead space in the ink tank becomes large, which affects the ink use efficiency. On the other hand, JP 2000-
Japanese Patent Laid-Open No. 103078 proposes a configuration in which a leaf spring having a plurality of bent portions is provided. However, when a plurality of bent portions and a leaf spring are used, the spring load increases, and the ink tank is particularly compact. In this case, it is not preferable that the generated negative pressure becomes larger than an appropriate value.

On the other hand, Japanese Unexamined Patent Publication No. 6-226993 proposes an arc spring. According to the publication, the shape of the bow spring is not complicated, and the spring load can be set to some extent by using the plate thickness and the material as parameters.

[0008]

In the arc-shaped spring described in the above publication, it is not always clear whether it is a plate-shaped spring or a linear spring, but in any case, the spring of one member is bent near the central portion. A spring force is generated by the bending, and when a deformation load is repeatedly applied to the spring, the bent portion may be fatigued and may eventually break. In addition, the bending requires a radius of curvature to some extent, and as in the case of using a coil spring, a dead space corresponding to the radius of curvature is generated when the spring is completely compressed.

That is, the bow spring is not suitable for an ink tank in which ink is repeatedly filled and used, and there is a point to be solved in terms of ink use efficiency. further,
The publication discloses a configuration in which a movable portion is formed symmetrically with an arcuate spring in between. However, the presence of the bent portion causes an unbalanced force that acts to deform the movable portion, causing the movable portion to move. It is possible that the deformation of the part becomes unstable, or the variation of the deformation of the movable part on one side also affects the movable part on the symmetrical side via the arc spring. It is also conceivable that the fluctuation acts on the print head via the ink supply path and adversely affects the ejection performance thereof.

The present invention has been made in view of the above problems, and has high durability even when repeatedly filled with ink and is excellent in ink use efficiency, and also affects the ejection performance of the print head. It is an object of the present invention to provide an ink tank having a structure that does not apply.

Another object of the present invention is to contribute to the construction of an ink jet print head and a printing apparatus capable of stable ejection operation.

[0012]

To this end, the ink tank of the present invention has a movable portion which is displaced or deformed in accordance with the amount of ink contained in at least a part thereof, and is deformed in accordance with the displacement or deformation of the movable portion. A negative pressure generating member for bringing the ink containing space into a negative pressure state by urging the movable portion, the negative pressure generating member being a pair of leaf springs having a substantially U shape, Is characterized by having the pair of leaf springs that are combined by making the open sides of the two opposite and engaging both ends of each other.

Here, the pair of leaf springs may be combined by engaging a concave portion formed at each of the both end portions with a convex portion fitted into the concave portion.

Further, each of the pair of leaf springs has one end portion in which the concave portion is formed and the other end portion in which the convex portion is formed, and the pair of leaf springs are provided with the concave portion and the convex portion. Can be combined by engaging the parts.

Here, the leaf spring is formed with a curvature, and with respect to a curved surface formed in the biasing force acting direction of the leaf spring, the convex portion with respect to a tangent line drawn from the root of the convex portion and the root of the opening of the concave portion. The amount of deflection a at the tip of the recess can be greater than 0 and less than or equal to the thickness of the leaf spring.

Further, in the above, as the movable part,
A pair of flexible thin film members facing each other, wherein the negative pressure generating member has a pair of plate-shaped members respectively joined to the pair of thin film members, the pair of plate springs by the pair of members. The urging force may be applied to the pair of thin film members, and the displacement or deformation of the pair of thin film members facing each other may be performed while maintaining a substantially parallel relationship.

Here, the member and the leaf spring may be integrally formed by welding separate members.

Alternatively, the member and the leaf spring may be formed by processing an integral plate material.

Further, the print head unit of the present invention is
It is characterized by comprising a print head for performing printing by ejecting ink onto a print medium, and an ink tank of any one of the forms described above.

Further, the ink jet printing apparatus of the present invention is characterized by performing printing on a print medium using the print head unit.

Furthermore, the present invention is an ink jet printing apparatus for performing printing using a print head for ejecting ink onto a print medium, and the ink jet printing apparatus according to any one of the above-mentioned forms for supplying ink to the print head. It is characterized by using an ink tank.

In these print head units or ink jet printing apparatuses, the print head has a heating element for generating heat energy that causes film boiling in the ink as energy used for ejecting the ink. Can be

In the present specification, the term "print" is used not only to form significant information such as characters and figures, but also to be visually perceptible regardless of whether it is significant or insignificant. Regardless of whether it is a material or not, it refers to a case where an image, a pattern, a pattern, etc. are widely formed on a print medium or a case where the print medium is processed.

The "print medium" is not limited to paper used in a general printing apparatus, but is widely applicable to ink such as cloth, plastic film, metal plate, glass, ceramics, wood and leather. In the following, the term "paper" or simply "paper" will be used.

Further, "ink" (sometimes referred to as "liquid") is to be broadly construed in the same way as the definition of "print", and when applied to a print medium, an image or a pattern is formed. , A liquid used for forming a pattern or the like, processing a print medium, or treating an ink (for example, solidifying or insolubilizing a coloring material in the ink applied to the print medium).

In the print head to which the present invention is applied, the heat energy generated by the electrothermal converter is used to cause film boiling in the liquid to form bubbles, and the liquid is ejected by the electromechanical converter. There are various forms proposed for inkjet recording, such as a form, a form of forming and discharging a droplet by using static electricity or an air flow, and a form using an electrothermal converter is preferably used from the viewpoint of miniaturization. To be

Further, the "nozzle" is a general term for an element such as the above-mentioned electrothermal converter which generates energy used for ejecting an ink or a liquid path communicating with the ejection opening and ink, unless otherwise specified. And

[0028]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings.

(Structural Example of Inkjet Printing Device)
FIG. 1 is a schematic plan view showing the overall configuration of an inkjet printing apparatus that employs an intermittent ink supply system as an embodiment of the present invention.

In the configuration of FIG. 1, the print head unit 1 is mounted on the carriage 2 in a replaceable manner.
The print head unit 1 is an ink tank that houses a plurality of print heads and a plurality of ink tanks that supply ink directly to the print heads (hereinafter, referred to as a second ink tank or a sub tank in relation to a first ink tank described later). And a connector (not shown) for transmitting and receiving a signal for driving the print head to cause the nozzles to perform the ink ejection operation. The print head unit 1 is mounted on the carriage 2 so as to be positioned and replaceable.
Is provided with a connector holder (electrical connection portion) for transmitting a drive signal or the like to each print head via the connector.

The carriage 2 is guided and supported so as to be able to reciprocate along a guide shaft 3 which extends in the main scanning direction and is installed in the apparatus main body. The carriage 2 is driven by the main scanning motor 4 via a transmission mechanism such as a motor pulley 5, a driven pulley 6 and a timing belt 7, and its position and movement are controlled. Further, the carriage 2 is provided with a home position sensor 10 in the form of, for example, a transmissive photointerrupter, and a shield plate 11 capable of shielding the optical axis of the transmissive photointerrupter at a fixed portion of the device corresponding to the home position of the carriage. Is provided. As a result, the home position is detected when the carriage 2 moves and the home position sensor 10 passes through the shield plate 11, and the carriage position and movement can be controlled with the detected position as a reference.

The print medium 8 such as a print sheet or a plastic thin plate is separated and fed one by one from the auto sheet feeder (ASF) 14 by rotating the pickup roller 13 via the gear by the feeding motor 15. Further, by the rotation of the carrying roller 9, the paper is carried (sub-scanning) through a position (print unit) facing the ejection port forming surface of the print head. The conveyance roller 9 is driven by transmitting the rotation of the line feed (LF) motor 16 via a gear.

At this time, the determination as to whether or not the paper is fed and the cueing at the time of feeding (determination of the print start position on the print medium in the sub-scanning direction) are upstream of the print position on the print medium conveyance path. This is performed based on the output of the paper end sensor 12 for detecting the presence or absence of the print medium arranged on the side. The paper end sensor 12 is also used to detect the rear end of the print medium 8 and determine the final print position on the print medium in the sub-scanning direction based on the detection output.

The print medium 8 has its back surface supported by a platen (not shown) so as to form a flat print surface in the print portion. In this case, the print head unit 1 mounted on the carriage 2 is held so that the ejection port forming surface of the print head projects downward from the carriage 2 and is parallel to the print medium 8. The print head is, for example, an ink jet head that ejects ink by using heat energy, and includes an electrothermal converter for generating heat energy that causes film boiling of the ink. That is, the print head of the print head unit 1 uses the pressure of the bubbles generated by the film boiling of the ink due to the heat energy applied by the electrothermal converter to eject the ink from the ejection port for printing. is there. Of course, other methods such as a method of ejecting ink by a piezoelectric element may be used.

Reference numeral 50 denotes a recovery system mechanism, which has a cap member used for sucking and recovering ink from the print head side and for protecting the ejection port forming surface of the print head. The cap member can be set to a joining / separating position with respect to the discharge port forming surface by a motor (not shown),
In the joined state, a suction pump (not shown) or the like generates a negative pressure inside the cap member, so that the suction recovery operation of the print head or the like is performed. Further, the ejection port forming surface of the print head can be protected by keeping the cap member in the joined state even when the printing apparatus is not in use.

Reference numeral 51 is a valve unit on the print head unit side for connecting the first ink tank to the second ink tank on the print head unit 1 side. 54
Is a valve unit on the ink supply side that forms a pair with the valve unit 51. Reference numeral 52 is a valve unit on the print head unit 1 side for similarly coupling an air pump. Reference numeral 53 is a valve unit on the air pump unit side that forms a pair with the valve unit 52.

These valve units 51 to 54 are set at a home position where the carriage 2 is located outside the print area in the main scanning direction or at a position near the home position.
By connecting the corresponding valve units at that position, the flow of ink or air through the valve units is allowed. Further, when the carriage 2 is separated from the position in the print area direction, the corresponding valve units are disconnected from each other, but the valve units 51 and 54 are automatically closed as the connection is released. I shall. On the other hand, the valve unit 52 is always in the open state.

Reference numeral 55 denotes a tube member, which is connected to a first ink tank (hereinafter also referred to as a main tank) 57 provided at a fixed portion of the apparatus and supplies ink to the valve unit 54. Reference numeral 56 is a tube member for a pneumatic circuit, and a pump unit 58 for pressurizing and depressurizing.
Is bound to. Reference numeral 62 is an intake / exhaust port of the pump unit 58.

The tube members do not have to be integrally formed, but may be formed by connecting a plurality of tube elements. A plurality of first and second ink tanks and tubes and valve units connecting them are provided in correspondence with the number of print heads.

The apparatus shown in FIG. 1 employs an intermittent ink supply system. That is, the print head unit 1 having the ink tank housing chamber that houses the relatively small second ink tank on the carriage 2 and the print head.
While having a relatively large first ink tank 57 in a portion other than the carriage of the printing device.
From the ink tank 57 of the second ink tank to the second ink tank at a proper timing, the carriage 2 is set to a position such as a home position and the valve unit is coupled to the ink supply system so that the ink can be supplied. . Also,
During the main scanning of the carriage 2, the ink supply system between the first and second ink tanks is spatially separated so that the first and second ink tanks are fluidly insulated.

Here, a system in which a supply system is configured so that an amount of ink corresponding to the amount of ejected ink is always continuously supplied to the print head (hereinafter, referred to as
In the case of adopting an on-carriage system that supplies ink by integrally attaching an ink tank to a print head that is mounted on a carriage or the like and reciprocally moves (main scanning), and is separable from the continuous supply system, However, there is a problem with respect to the projected area and volume of the members (print head and ink tank) that move with the carriage in the direction perpendicular to the main scanning direction. That is, when a large-capacity ink tank is used, the printing apparatus becomes large, and conversely, when a small, particularly portable printing apparatus is configured, only an extremely limited capacity ink tank can be used. As a result, the frequency of replacing the ink tank integrated print head or the ink tank becomes very high.

Further, in the continuous supply system, the ink tank is fixedly installed in another part of the printing apparatus separately from the print head mounted on the carriage, and the ink tank is connected via the flexible tube. When a tube supply system that supplies ink by connecting the print head and the print head is adopted, the member that moves together with the carriage during main scanning can be downsized to some extent, but the print head on the carriage and the outside of the carriage can be reduced. A space is required for the tube member that supplies ink by connecting with the ink tank at the position of (1) and follows the carriage, and thus it is difficult to reduce the size accordingly. Further, in recent years, the carriage tends to be scanned at high speed in response to the speeding up of the printing operation, and the pressure of the ink in the ink supply system with respect to the print head fluctuates due to the violent swinging of the following tube. It is highly desirable to provide various complicated pressure buffering mechanisms in order to suppress the above, and it is difficult to miniaturize in that respect as well.

On the other hand, according to the intermittent supply method as in the above example, there are various problems due to the size of the moving member such as the ink tank, which has been a limitation of downsizing in the continuous supply method, and the rocking of the tube. You can basically solve the occurrence of dots.

(Other Configuration Example of Inkjet Printing Apparatus) In the intermittent supply system of FIG. 1, the valve unit is connected only when the ink is filled in the first ink tank, while the first unit is connected during the printing operation. Also, the ink supply system between the second ink tanks is spatially separated. On the other hand, an intermittent supply system having a configuration in which the first and second ink tanks are fluidly insulated by blocking the ink flow path by a valve or the like without performing such separation is adopted. You can also

FIG. 2 schematically shows an ink jet printing apparatus to which an intermittent supply system using a tube mechanism which is always connected is applied. In FIG. 2, parts that can be configured similarly to FIG. 1 and are not related to the description of the supply system of this example are omitted for simplification.

In FIG. 2, 70 is a flexible tube for a pneumatic circuit, one end of which is connected to the second ink tank of the print head unit, and the other end is for the electromagnetic valve unit 72 and the pneumatic circuit. It is connected via a tube member 56 to a pump unit 58 for pressurization and decompression. 71
Is a flexible tube member for ink supply whose one end is connected to the second ink tank of the print head unit, and the other end is the first ink via the electromagnetic valve unit 72 and the ink supply tube member 55. Tank 5
Connected to 7.

That is, even when using the tube mechanism which is always connected as described above, the electromagnetic valve unit 72 is used.
The intermittent supply system can be configured by interposing a flow path opening / closing means such as the above, and appropriately controlling the opening / closing of the flow path opening / closing means during the ink filling operation and the printing operation in the second ink tank.

(Sub-Tank and Manufacturing Method Thereof) According to the intermittent supply method as exemplified above, due to the size of the moving member such as the ink tank, which has been a limitation of downsizing in the continuous supply method, or the swing of the tube. The generation of various problems can be basically solved.

In the present embodiment, even when there are a plurality of types of ink used for dealing with colorization, by appropriately configuring the ink tank accommodating chamber, the structure can be made compact and simple. Moreover, the size of the print head unit and the printing apparatus can be further reduced thereby.

Here, the sub-tank (in this section, simply referred to as "ink tank") arranged in the ink tank accommodating chamber according to the embodiment of the present invention and its manufacturing method will be described.

FIG. 3 is a perspective view of an ink tank 127 manufactured by the following steps, which is a frame 1 having a rectangular frame shape.
In the upper and lower openings of 15, the upper and lower spring / seat unit 1
It has a sealed structure with 14 attached. The spring / seat unit 114 includes a spring unit 112 including a spring 107 and a pressure plate 109, and a flexible tank sheet (flexible member) 106, as described later. The frame 115 is formed with a first ink supply port 128 and a second ink supply port 129 that communicate with the inside of the ink tank 127.

4 to 8 are views for explaining a method of manufacturing such an ink tank 127.

First, FIGS. 4 (a), 4 (b) and 4 (c) are explanatory views of a process of molding the flexible tank sheet 106 into a convex shape.

The sheet material 101 as a forming material of the tank sheet 106 is formed from a raw material into a large size sheet, and the sheet material 101 occupies an important factor of ink tank performance. This sheet material 101 has low permeability of gas and ink components,
In addition, it is required to have flexibility and durability against repeated deformation. Suitable materials include PP, PE, PV
It may be DC, EVOH, nylon or the like, and as the composite material, a material such as aluminum or silica vapor-deposited may be used, and these may be laminated and used. Particularly, by stacking and using PP or PE having excellent chemical resistance and PVDC having excellent gas / water vapor barrier performance, excellent ink tank performance can be exhibited.
Further, the thickness of such a sheet material 101 is preferably about 10 μm to 100 μm in view of flexibility and durability.

Such a sheet material 101 is shown in FIG.
As shown in (a), the convex portion 103 and the vacuum hole 10
4 and a convex mold using a molding die 102 having a temperature adjusting mechanism (not shown). That is, the sheet material 101 is adsorbed to the vacuum holes 104, and the molding die 1
It is molded into a convex shape along the convex portion 103 by the heat from 02. The sheet material 101 is formed into a convex shape as shown in FIG. 4B, and then the tank sheet 1 is formed as shown in FIG. 4C.
It is cut out into a predetermined size as 06. The size may be any size suitable for the manufacturing apparatus in the next step, and can be set according to the volume of the ink tank 127 that stores the ink.

FIG. 5A is an explanatory view of the manufacturing process of the spring unit 112 used for making the inside of the ink tank 127 a negative pressure. Spring 1 preformed in a semi-circle shape
07 is attached to the spring receiving jig 108, and from above,
Pressure plate 10 by spot welding using welding electrode 111
Attach 9. A thermal adhesive material 110 is attached to the pressure plate 109. The spring 107 and the pressure plate 109 form a spring unit 112.

FIG. 5B is an explanatory view of a process of attaching the spring unit 112 to the tank seat 106. The spring unit 112 is positioned and arranged on the inner surface of the tank seat 106 placed on a receiving jig (not shown). Then, the heat adhesive 113 is heated by using the heat head 113, so that the spring unit 112 and the tank sheet 106 are bonded to each other to form the spring / seat unit 114.

FIG. 6A shows the spring / seat unit 11
It is explanatory drawing of the process of welding 4 to the frame 115. The frame 115 is fixed to the frame receiving jig 116. Sheet suction jig 117 surrounding the frame 115
After the frame 115 is positioned and arranged, the spring / seat unit 114 is attracted to the vacuum hole 117A to hold the unit 114 and the frame 115 relatively without displacement. Then, the heat head 118 heat-welds the annular joint surfaces of the peripheral portion of the frame 115 on the upper side in the drawing and the tank seat 106 of the spring / seat unit 114. The sheet suction jig 117 makes the peripheral edge of the upper side of the frame 115 in FIG. 6A and the peripheral edge of the tank sheet 106 of the spring / seat unit 114 evenly face each other, so that the joint surface thereof is extremely high. It will be heat-welded and sealed uniformly. Therefore, the sheet suction jig 117 is important for heat welding so as to ensure uniform sealing.

FIG. 6B shows the tank sheet 1 protruding outside the frame 115 by a cutter (not shown).
It is explanatory drawing of the process of cutting out the part of 06. In this way, the spring / seat / frame unit 119 is completed by cutting off the portion of the tank seat 106 that protrudes from the frame 115.

FIGS. 7 and 8A and 8B show such a spring / seat / frame unit 119 in which another spring / seat unit 114 manufactured by the above-described steps is manufactured.
It is explanatory drawing of the process of heat-welding.

As shown in FIG. 7, the spring / seat / frame unit 119 is attached to a receiving jig (not shown),
A suction jig 12 whose position is defined relative to the receiving jig 12
The outer periphery of the spring / seat / frame unit 119 is surrounded by 0. The receiving jig makes surface contact with the flat surface portion 106A of the outer surface of the tank seat 106 of the spring / seat / frame unit 119, and the flat surface portion 106A.
Are held as shown in FIGS. 8 (a) and 8 (b). In the other spring / seat unit 114, the flat surface portion 106A of the outer surface of the tank seat 106 is suction-held by the pressing jig 121, and the pressing jig 121 is lowered,
The tip part 1 of the spring 107 on the side of the spring / seat unit 114
07A and 107B and the tip portions 107A and 107B of the spring 107 on the side of the spring / seat / frame unit 119 are fitted substantially at the same time. That is, one tip portion 107A of the spring 107 has a convex shape and the other tip portion 107B has a concave shape so that they are fitted into each other by self-alignment. One spring member is formed by joining as a structure.

Further, the pressing jig 121 is lowered to
As shown in FIG. 8A, the pair of springs 107 are compressed. At this time, the pressing jig 121 widely presses the flat portion 106A on the upper side in FIG. 7 of the spring / seat unit 114, that is, the flat region on the upper side of the tank seat 106 formed on the convex portion. As a result, the position of the flat portion 106A of the tank seat 106 is regulated, and the spring / seat unit 114 approaches the lower unit 119 and the jig 120 while being kept in parallel. Therefore,
As shown in FIG. 8B, the peripheral edge portion of the tank seat 106 of the spring / seat unit 114 contacts the surface of the suction jig 120 and is suction-held in the vacuum hole 120A.
The welding surface of the frame 115 (the upper bonding surface in the figure) is evenly faced. And in this state,
By the heat head 122, a peripheral edge portion on the upper side in the drawing of the frame 115 of the spring / seat / frame unit 119,
The tank seat 106 of the spring / seat unit 114,
The annular joint surfaces of are heat-welded to each other.

Thus, the flat portion 106A of the tank seat 106 of the upper unit 114 and the lower unit 1
The flat portions 10 of the pair of tank seats 106 are compressed by compressing the pair of springs 107 while maintaining parallelism with the flat portion 106A of the tank seat 106.
The ink tank 127 having a high parallelism of 6 A can be stably mass-produced. Also, a pair of springs 107
8 is compressed and deformed uniformly in the left and right direction in FIGS. 8A and 8B, a force that tilts the spring / seat unit 114 is not generated, and the parallelism of the flat portions 106A of the pair of tank seats 106 is not generated. It is possible to more stably produce the ink tank 127 having a high price. Further, as the volume inside the ink tank 127 changes, a pair of springs 10 is formed.
8 is compressed and deformed uniformly in the left and right in FIGS. 8A and 8B, the flat portion 106 of the pair of tank seats 106.
In A, the facing distance changes while maintaining high parallelism, and as a result, ink can be stably supplied. In addition, the flat portion 106 of the flexible tank sheet 106
Since an unreasonable force such as tilting A is not applied, the ink tank 127 has improved sealability, pressure resistance, and durability.

After that, the ink tank 127 of FIG. 3 is completed by cutting off the portion of the tank sheet 106 protruding to the outside of the frame 115. Ink tank 12
The inside of 7 has a sealed structure in which the first ink supply port 128 and the second ink supply port 129 communicate with the outside.

FIG. 9 is an explanatory diagram of a process of attaching the ink tank 127 to the recording head.

Head chip 133 constituting the recording head
Is attached to the ink tank storage chamber 130, and a plurality of ink tanks 127 are attached inside the ink tank storage chamber 130. The ink tank 127 is attached to the ink tank attachment portion 131 by welding or adhesion. Further, the ink tank 127 of this example is attached with the ink supply ports 128 and 129 facing downward. After that, the lid 132 is attached to the opening of the ink tank accommodating chamber 130 by welding or adhesion, and the ink tank accommodating chamber 13
The inside of 0 is a semi-closed space. Thus, the recording head including the ink tank is configured. The head chip 133 may constitute an inkjet recording head, and as the inkjet recording head, for example,
A configuration including an electrothermal converter for ejecting ink droplets from the ink ejection port can be adopted. In other words, it is possible to adopt a configuration in which the ink is film-boiling by the heat generation of the electrothermal converter and the bubbling energy is used to eject the ink droplet from the ink ejection port. An ink jet cartridge can be constructed by connecting such an ink jet recording head and an ink tank.

FIG. 10 is a sectional view of the ink tank accommodating chamber 130 of FIG. 9 having an ink tank.

Ink can be stored in the ink tank 127, and the ink is supplied from the first ink supply port 128 of the ink tank 127 to the supply path 136 via the filter 137 and further to the head chip 133. Supplied. In the head chip 133 of this example, a heater board 134 is bonded so as to form an ink jet recording head. The heater board 134 is provided with an ink discharge channel and an orifice, and an electrothermal converter (heater). ) Is provided, and the ink supplied from the ink tank 127 can be ejected. It is possible to fill the ink tank 127 with ink from the second supply port 129. That is, a joint seal 139 is fixed to the second supply port 129 by a joint seal plate 139 so as to prevent ink leakage and allow ink filling so as to seal the lower opening 141 of the tank storage chamber 130. Joint seal 13
The joint seal 138 is provided with a slit opening into which a needle-shaped supply pipe can be inserted. Ink tank 1
At the time of supplying the ink to the inside of 27, the needle-shaped supply pipe is inserted into the slit opening of the joint seal 138, and the ink is supplied into the ink tank 127 through the supply pipe. When ink is not supplied into the ink tank 127, ink is not leaked because the slit opening is closed by the elasticity of the joint seal 138. Reference numeral 140 denotes a communication passage communicating with the second supply port 129, which can be formed in advance inside the frame 115.

Further, the ink tank accommodating chamber 130, which has a semi-closed structure by the lid 132, has a communication port 142 of a small hole.
It communicates with the outside only by. The inside of the ink tank storage chamber 130 is depressurized by blocking the inside of the ink tank storage chamber 130 from the atmosphere by closing the communication port 142 or discharging the air inside the ink tank storage chamber 130 from the communication port 142. It is possible to increase the negative pressure in the ink tank 127.

Further, by repeating the pressure reduction and pressure increase in the ink tank accommodating chamber 130, the second ink supply port 129
It is also possible to automatically suck and replenish ink into the ink tank 127. At that time, the ink tank storage chamber 13
Since the spring 107 elastically deforms with good responsiveness according to the pressure change within 0, it can be suitably used as a small ink tank to which ink is frequently replenished.

(Structure and Operation of Spring) FIGS. 11A and 11B are schematic sectional views of the above-described ink tank (sub-tank). Further, FIGS. 12A to 12C are schematic perspective views showing the deformed state of the pair of spring units 112 according to the present embodiment step by step.

In FIGS. 11A and 11B, one spring 107 is connected to the pressure plate 109 by spot welding as described above, and the tank sheet 10 is connected via the pressure plate 109.
6, which is adhesively fixed to the tank seat 106 and the frame 11
It is welded to 5. The opposite side has the same configuration symmetrically. The spring 107 exerts a force in the direction of expanding the tank sheet 106 to the outside, and gives a negative pressure in the ink tank. In this embodiment, a pair of springs 107 are combined to form a negative pressure generating member, and each spring 107 is engaged at a joint 159.

As shown in FIG. 12, the pair of spring units 112 are arranged in the order shown in FIG. 12C from the state shown in FIG. When the ink is deformed and is filled with ink on the other hand, the state returns from the state shown in FIG. 6C to the state shown in FIG. In this way, the spring is repeatedly deformed in accordance with the repeated discharge and filling of the ink.

FIGS. 13A and 13B show a pair of springs 1 corresponding to the states of FIGS. 12A and 12C, respectively.
It is an enlarged view of the engagement part 159 of 07. In any state, the engaging portions are fitted at both ends due to the concavo-convex shape of each other. As in the arc spring disclosed in Japanese Patent Laid-Open No. 6-226993, at least one engaging portion is integrally formed as one.
When a negative pressure generating member formed by bending parts is used, the bending portion may be fatigued during repeated deformation operation and fatigue fracture may occur, but in the present embodiment, a pair of negative pressure generating members is used. The two springs are combined to form a two-part structure, and the engaging portions of the springs are formed by concavo-convex parts to disperse the stress generated in the spring member during deformation,
It is possible to avoid fatigue destruction.

In the present embodiment, the convex width of the convex portion is made smaller than the opening width of the concave portion by, for example, 0.1 mm or more so that the engaging portion can move relative to both ends. . With this configuration, the stress distribution described above is performed more efficiently.

Further, in the structure in which the movable portion is formed symmetrically with the arcuate spring interposed, the force for deforming the movable portion acts unbalanced due to the presence of the bent portion, and the deformation of the movable portion is unstable. Or the variation of the deformation of the movable part on one side also affects the movable part on the symmetrical side via the arcuate spring, and the pressure plate and the tank seat of the movable part on the opposite side are also tilted, and other members such as the frame. May interfere with. On the other hand, the conditions of the engaging portion of the present embodiment are the same at both ends, and the pair of movable portions (pressure plate 109 or tank seat 106) can be displaced while maintaining a substantially parallel state. Even if the movable part is deformed in a state where the pressure plate is tilted from the equilibrium state, this fear can be avoided because the two parts of the engaging part are less restricted from each other. In addition, the pressure fluctuations in the ink tank can be effectively reduced by these, and the possibility that the ejection performance of the print head is adversely affected is extremely reduced.

FIG. 14 is a schematic diagram showing the material 107 'of the spring 107 in this embodiment. As is clear from this figure, in the present embodiment, the end shape of the spring material 107 'is one end 152 having a concave shape and the other end 153 having a convex shape. Therefore, if one kind of spring material 152 is prepared, the rest is bent to form the spring 107,
Since it is sufficient to combine the pair of springs 107, the manufacturing cost is advantageous.

FIG. 15 is a schematic diagram for explaining the shape of the end portion of the spring in this embodiment. FIG. 7A is a schematic side view showing a state where the spring 107 is curved, and FIG. 7B is a schematic enlarged view of an end portion of the spring 107 (A portion in FIG. 7A). is there. In the present embodiment, the amount of deflection a of the tip of the uneven portion with respect to the tangent at the root position of the uneven portion of the surface on the spring force acting side is 0 <a ≦ t (plate thickness).
Are formed to have a relationship of. With this configuration,
As shown in FIG. 7C, even when the pair of springs 107 are completely closed, the concave portion 153 and the convex portion 154 overlap each other, and the engaging portion does not come off.

The structure of the spring and the like is not limited to the above-mentioned embodiment, but various structures can be adopted.

16 (a) and 16 (b) are schematic sectional views showing a liquid container according to another embodiment, and FIG. 16 (c) is a perspective view of a negative pressure generating member. In the above embodiment, the spring has a shape having a curvature over the entire length, but in the present embodiment, the spring 207 is formed by straight lines and bending.
Is formed. The combination of the pair of springs and the shapes of the engaging portions thereof are the same as in the above embodiment.

In this embodiment, the pressure plate 1 of the spring 207 is
Since it is possible to secure a wide bonding area with respect to 09, the bonding of both is stable and the bonding accuracy can be improved. Although the durability of the bent portion against repeated deformation is inferior to that of the above-described embodiment, the inner angle of the bent portion is 90 degrees or more, and therefore, the Japanese Patent Laid-Open No. 6-226993.
Compared with the durability in the case of using a one-member spring whose central portion is turned by 180 degrees or more like the bow-shaped spring disclosed in the publication, it has much more durability.

FIGS. 17A, 17B and 17C are a schematic plan view, a side view and a perspective view, respectively, for explaining a spring unit according to still another embodiment. In the above description, the separate pressure plate and spring are integrated by spot welding or the like to form a spring unit, but in the present embodiment, the spring unit is formed of a material that integrally has a portion functioning as a pressure plate and a spring in advance. Is. The spring unit 112 can be manufactured by the following steps.

That is, after forming the outer shape of a spring portion by wire cutting or etching from a spring unit material which is a single metal plate, the spring 30 is bent by bending.
Mold to 7. The remaining flat portion becomes the pressure plate 309. When there is a possibility that burrs or edges are present on the adhesive surface side of the sheet 106 and the sheet 106 is damaged, the outer shape of the spring may be punched by performing press working from the adhesive surface side. . The concavo-convex shape of the spring end portion that becomes the engaging portion is the same as in the above example.

According to this embodiment, when manufacturing the sub tank, the number of parts can be reduced and the welding process of the spring and the pressure plate can be omitted, so that the manufacturing cost can be reduced. Further, when the spring is completely closed, the spring 307 is housed in the pressure plate cutout portion,
The volume of the spring unit 312 occupying in the ink tank is substantially only the material volume, and the storage or use efficiency of ink is also improved.

Since the pressure plate has a function of appropriately controlling the displacement of the sheet, it is required to have a certain degree of rigidity. Therefore, when the elastic force of the spring formed of the same material becomes high, a notch or It is also possible to generate a desired negative pressure by forming the spring portion such as punching.

(Structure and operation of ink tank accommodating chamber and sub tank) As is apparent from FIG. 9, the ink tank accommodating chamber of this embodiment has four independent sub tanks 127 for storing inks of four tones. They are accommodated in parallel in the direction corresponding to the main scanning direction without interposing partitions or partitions.

Further, the four sub-tanks 127 have a structure for changing the shape according to the amount of ink stored and changing the internal volume, and for independently maintaining the shape. That is, each of the four sub-tanks 127 has a sealed ink storage structure in which a pair of flexible thin film members (tank sheets) 106 facing each other are provided, and the inside of each sub-tank 127 consumes ink and has a minimum internal volume. Up to the point where the holding force of the meniscus formed in the nozzle is balanced to generate an appropriate negative pressure within a range in which ink can be ejected from the nozzle, and a pair of springs facing each other when the internal volume changes. And a pressure plate 109 for restricting the displacement or deformation of the tank seat while maintaining a substantially parallel relationship.

Further, the inside of the ink tank accommodating chamber has a small hole 142 as an intake / exhaust port. The valve unit 52 is connected to the small hole 142, and the valve unit 52 is normally open in a state where it is not connected to the valve unit 53 on the air pump unit side (during a printing operation or the like). Inside the small hole 14
2 through the valve unit 52 to communicate with the atmosphere.
Therefore, the deformation (contraction) operation of the sub tank 127 due to the ink consumption due to the ejection operation or the like is not hindered.

The shapes of the four sub-tanks 127 change independently as ink is consumed. That is, the remaining amount of ink is unbalanced for each type of ink in accordance with the amount of ink of each color tone used according to the image to be formed, and the ink has various shapes. For example, when ink filling is performed from this state, the carriage 2 is set to a home position located outside the print area in the main scanning direction or a position near the home position, and the corresponding valve units are connected at that position. , Allow the flow of ink and air between the valve units. And the pump unit 58
When the pressure in the ink tank accommodating chamber is reduced by depressurizing the ink, each sub-tank 127 expands while sucking ink from the corresponding first ink tank 57. Even if the ink remaining amount in the sub-tank 127 is different for each type of ink as shown in FIG. 12, each expansion is blocked when the ink is sufficiently filled and the decompression force is balanced with the tension of the tank sheet 106. . That is, according to the present embodiment, it is theoretically unnecessary to perform fine control for filling the specified amount of ink in accordance with the difference in the remaining ink amount for each type.

Since the mixed gas may be accumulated (accumulated) in each sub-tank 127 due to some factor, the operation of pressurizing the inside of the ink tank accommodating chamber is performed prior to the ink filling operation, and the sub-tank 127 is It is also possible to discharge the gas staying in the upper part toward the first ink tank side.

If the spring 107 is deformed to the neutral position or the pressurizing side in a state where the ink is sufficiently filled and the sub-tank 127 is completely expanded, the pressurizing operation is performed for a short time after the ink filling operation. , The ink in the sub-tank 127 is slightly pushed back to the first ink tank 57 side to contract the sub-tank 127, and the leaf spring member 1
It is also possible to perform an operation for causing 07 to generate a proper negative pressure.

(Others) With the above-described configuration of the ink tank housing chamber and the sub tank, the valve unit is connected when the ink is filled in the sub tank, while the ink is supplied between the first ink tank and the sub tank during the printing operation. The system is not limited to the printing apparatus of FIG. 1 in which the system is spatially separated, and an intermittent supply system having a configuration in which the first and second ink tanks are fluidly insulated without performing such separation is adopted. It can also be applied to the printing apparatus of FIG.

Further, although the ink tank integrated with the print head has been described in the above example, the both may be separable or separate. Further, the case where the present invention is applied to a printing apparatus that employs an intermittent supply system that is preferable for making the printing apparatus small and portable, that is, the case where ink tanks (sub-tanks) are repeatedly filled with ink has been described. Even in a printing apparatus that adopts the continuous supply method, it is preferably applicable in that it is possible to use an ink tank that is repeatedly filled with ink and that a stable ejection operation is obtained. It can also be expected to improve the recyclability of the ink tank.

The printing apparatus of the present invention is different from the image data supply source in the form of a computer for creating and processing data such as images relating to printing, a reader unit for image reading, or a digital camera. It may be configured in the body or may be separable or inseparable integrally.

[0095]

As described above, according to the present invention,
It is possible to provide an ink tank having a structure that has high durability even when repeatedly filled with ink and is used, is excellent in ink use efficiency, and has a structure that does not affect the ejection performance of the print head. In addition, it is possible to contribute to the configuration of an inkjet print head and a printing apparatus that can perform stable ejection operation.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an overall configuration of an inkjet printing apparatus to which an intermittent supply method according to an embodiment of the present invention is applied.

FIG. 2 is a schematic plan view showing an overall configuration of an inkjet printing apparatus to which an intermittent supply system using a tube mechanism that is always connected is applied to the configuration of FIG.

FIG. 3 is a perspective view of an ink tank applicable to the present invention.

4 (a), (b) and (c) are explanatory views of a process of forming a tank sheet in the ink tank of FIG.

5A is an explanatory diagram of a manufacturing process of a spring unit in the ink tank of FIG. 3, and FIG. 5B is an explanatory diagram of a manufacturing process of a spring / sheet unit in the ink tank of FIG.

6A and 6B are explanatory views of the manufacturing process of the spring, seat, and frame unit in the ink tank of FIG.

FIG. 7 is an explanatory diagram of a process of connecting the spring / seat unit and the spring / seat / frame unit in the ink tank of FIG. 3;

8A and 8B are cross-sectional views of the main part in the joining step of FIG.

FIG. 9 is an explanatory diagram of a mounting process of the ink tank of FIG.

10 is a cross-sectional view of a main part of the ink tank of FIG. 9 in a mounted state.

11A and 11B are schematic cross-sectional views of the ink tank (sub-tank) of FIG.

12 (a) to 12 (c) are schematic perspective views showing the deformed state of a pair of spring units in the sub tank in stages.

13 (a) and (b) are respectively FIG.
It is an enlarged view of the engagement part of a pair of springs corresponding to the state of (a) and (c).

FIG. 14 is a schematic diagram showing a material for forming the spring in FIGS. 11 to 13.

15 (a) to 15 (c) are schematic diagrams for explaining the end shape of the spring in FIGS. 11 to 13.

16A and 16B are schematic cross-sectional views showing an ink tank according to another embodiment, and FIG. 16C is a perspective view of a negative pressure generating member.

17 (a), (b) and (c) are respectively,
It is a typical top view, a side view, and a perspective view for explaining a spring unit concerning other embodiments.

[Explanation of symbols]

1 Print head unit 2 carriage 3 Guide shaft 4 Main scanning motor 8 print media 9 Conveyor rollers 10 Home position sensor 15 Feed motor 16 line feed (LF) motor 50 Recovery system mechanism 51-54 Valve unit 55 Ink tube member 57 First Ink Tank 56 Pneumatic circuit tube member 58 pump unit 59 Atmosphere Communication Department 106 Tank sheet (flexible member) 106A flat part 107,207,307 springs 107A, 107B Tip 109,309 Pressure plate 110 thermal adhesive 112, 312 spring unit 114 Spring / Seat Unit 115 frames 119 Spring, seat, frame unit 121 Holding jig 122 heat head 127 ink tank 128 1st ink supply port 129 Second ink supply port 130 ink tank chamber 133 head chip 142 Intake and exhaust port 152 recess 153 convex 159 Engagement part

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nobuyuki Kuwahara             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Hiroyuki Ishinaga             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2C056 EA21 EA25 KC02 KC09 KC14                       KC27

Claims (12)

[Claims] 1. A movable part that is displaced or deformed in accordance with the amount of ink contained in at least a part, and an ink containing space is formed by deforming and biasing the movable part in accordance with the displacement or deformation of the movable part. And a negative pressure generating member for setting a negative pressure state, the negative pressure generating member being a pair of leaf springs having a substantially U shape, the open sides of which are opposed to each other, and both end portions of both are engaged. An ink tank comprising the pair of leaf springs combined and combined. 2. The pair of leaf springs are combined by engaging a concave portion formed at each of the both end portions with a convex portion that fits into the concave portion. Ink tank described. 3. The pair of leaf springs each have one end portion formed with the concave portion and the other end portion formed with the convex portion, and the pair of leaf springs include the concave portion and the convex portion. The ink tank according to claim 2, wherein the ink tank is combined by engaging with a portion. 4. The leaf spring is formed so as to have a curvature, and with respect to a curved surface formed in the biasing force acting direction of the leaf spring, the protrusion and the tangent line drawn from the root of the protrusion and the root of the opening of the recess, The ink tank according to claim 2 or 3, wherein a deflection amount a of a tip portion of the recess is greater than 0 and is equal to or less than a thickness of the leaf spring. 5. The movable part includes a pair of flexible thin film members facing each other, and the negative pressure generating member has a pair of plate-like members respectively bonded to the pair of thin film members. The biasing force of the pair of leaf springs acts on the pair of thin film members by the pair of members, and the displacement or deformation of the pair of thin film members facing each other is performed while maintaining a substantially parallel relationship. The ink tank according to any one of claims 1 to 4, wherein: 6. The ink tank according to claim 5, wherein the member and the leaf spring are integrally formed by welding separate members. 7. The ink tank according to claim 5, wherein the member and the plate spring are formed by processing an integral plate-shaped material. 8. A print head for performing printing by ejecting ink onto a print medium, and the ink tank according to claim 1.
A printhead unit characterized by including. 9. The print head according to claim 8, wherein each of the print heads has a heat generating element that generates heat energy that causes film boiling in the ink, as energy used to eject the ink. Printhead unit as described. 10. An ink jet printing apparatus for performing printing using a print head for ejecting ink onto a print medium, wherein the ink is supplied to the print head. An inkjet printing apparatus, which uses an ink tank. 11. An ink jet printing apparatus, which prints on a print medium by using the print head unit according to claim 8. 12. The print head according to claim 10, further comprising a heating element that generates heat energy that causes film boiling in the ink, as energy used for ejecting the ink. The inkjet printing apparatus described.