JPH09193409A - Ink tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink tank good in ink holding capacity by providing a capillary tube member to the ink supply part of the ink tank equipped with an ink holding chamber having an ink holding negative pressure generation member housed therein and the hole communicating with the atmosphere formed to the ink holding chamber. SOLUTION: An ink tank 80 is divided into an ink supply liquid chamber 100 and an ink holding chamber 101 by a partition rib 102 and a communication hole 105 is provided to the partition rib 102 so as to allow the ink supply liquid chamber 100 to communicate with the ink holding chamber 101. The ink holding chamber 101 is almost closely packed with a negative pressure generation member 103 in a compressed state and allowed to communicate with the atmosphere by the atmosphere communication hole 104 provided to the upper part of the ink holding chamber. The ink supply liquid chamber 100 is closely filled with ink and a capillary tube member 61-1 is inserted in an ink supply port 58-1 under pressure in a hermetically closed state and the ink supply liquid chamber 100 is held to an almost simple hermetically closed state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink tank which is incorporated in a recording device such as an inkjet recording device and stores ink which is a used liquid.

[0002]

2. Description of the Related Art Conventionally, in a recording apparatus for recording on a recording medium using ink, an ink tank for supplying ink to a print head is roughly classified into two types according to an ink holding system.

One of them is a system in which an ink tank for holding ink is built in the main body of the recording apparatus, and ink is supplied to the ink supply path from the ink tank to the recording head by using a tube or the like. In this method, the ink supply system between the ink tank and the recording head becomes large, and it is difficult to reduce the size and cost of the recording apparatus main body. In addition, the ink in the supply system is likely to be interrupted, the amount of ink consumed for recovery increases, and the running cost of the ink tank increases. In order to maintain the meniscus of the ink ejection unit, the ink tank is placed at a position lower than the recording head,
Since the negative pressure due to the water head difference is used, the meniscus fluctuates due to the water head difference of the ink tank, which causes deterioration of print quality. Also, when trying to reduce the head difference,
The shape of the ink tank is greatly restricted.

The second method is to arrange an ink absorber in the entire ink tank, hold the ink by its capillary force, and balance it with the capillary force of the ink ejection hole of the recording head to form a meniscus of the ink ejection hole. Is a method of maintaining. This all-absorber ink tank system holds less ink than the maximum ink holding capacity of the absorber, and uses the capillary force at the gas-liquid interface between the atmosphere and the ink in the atmosphere communicating hole side that does not hold the ink. In order to maintain the above, the head pressure changes by the amount of the fluctuation of the liquid surface due to the consumption of ink. That is, the negative pressure is changed by the amount of change in the head pressure, the meniscus of the ejection hole is changed, the print quality is deteriorated, and the shape of the ink tank is greatly restricted. Further, in this method, the amount of ink consumed from the ink ejection holes is small relative to the amount of ink held by the absorber. In other words, a large amount of ink remains in the absorber, resulting in a very high running cost. In particular, when detecting the remaining amount of ink, it is possible to detect the presence or absence of ink using the conductivity of the ink by providing two electrodes inside the ink absorber and outside the ink absorber. Since a large amount of ink remains, it is impossible to detect the remaining amount of ink every time the ink is consumed. Further, since the electrode is constantly immersed in the ink, there is a problem that the ink is likely to be deteriorated due to deterioration such as oxidation of the electrode.

On the other hand, JP-A-56-67269 and JP-A-59-98857 disclose a spring bag ink tank system using an ink bag biased by a spring in the ink tank. The spring bag method is a method that adjusts the pressing force of the spring with respect to the ink consumption so that the negative pressure change is small, but the spring shape is greatly restricted to obtain a predetermined internal negative pressure, and it is fixed so that the bag is sealed in the ink tank. Must be done and the process becomes very complicated and the ink tank becomes very expensive.

Further, in Japanese Patent Laid-Open No. 2-214666, a divided ink chamber ink tank system in which the inside of the ink tank is divided into a plurality of ink chambers and the respective ink chambers are communicated by a fine communication passage capable of generating negative pressure Is disclosed.

In this divided ink chamber ink tank system,
Compared to the spring bag method, the structure can be simplified and stable generation of internal negative pressure can be realized, but if the holding posture of the ink tank is changed, the internal negative pressure will decrease depending on the state of the remaining ink, and ink leakage will occur. There is a restriction on the attitude of the ink tank. Further, Japanese Patent Application Laid-Open No. 6-040043 discloses an improved type ink chamber ink tank system that is an improved type of the ink chamber ink tank system and is excellent against environmental changes. In this method, a negative pressure generation accommodating portion that accommodates a negative pressure generation member and an ink accommodating portion that accommodates ink adjacent to the negative pressure generation member accommodation portion are connected by a passage, and a passage that introduces the atmosphere is connected to the communication passage. It is formed up to the vicinity.

Here, the structure of the improved division chamber ink tank system and the internal negative pressure change for each ink consumption will be described with reference to FIGS. 12 and 13.

FIG. 12 is a block diagram of a conventional improved divisional ink chamber ink tank. An ink supply liquid chamber 71 containing a negative pressure generating member 70 for holding ink for supplying ink to the print head is provided, and the ink supply liquid chamber 71 is provided.
Are in communication with the ink in the ink holding chamber 72 through a communication passage 73 formed in the lower part.

When the ink in the ink tank 74 is consumed, the atmosphere is introduced from the atmosphere communicating hole 75 provided for communicating the ink supply liquid chamber 71 with the atmosphere, and a sudden change in the internal negative pressure does not occur.

Next, a change in internal negative pressure due to ink consumption will be described. First, the back pressure of the ink tank 74 is held in a state where the ink head pressure of the ink supply liquid chamber 71, the capillary force of the negative pressure generating member 70 and the ink head pressure of the ink holding chamber 72 are balanced. Here, the ink supply hole 76
When more ink is supplied, the ink held in the negative pressure generating member 70 in the ink supply liquid chamber 71 is consumed.

The relationship between the remaining amount of ink and the internal negative pressure, that is, the back pressure at this time can be expressed by the slope of the section AB in FIG. The back pressure at 74 rises. Further, when the ink is consumed from the ink supply hole 76, the ink is held with the atmosphere of the ink supply liquid chamber introduced from the atmosphere communication hole 75 in the communication passage 73 communicating between the ink supply liquid chamber 71 and the lower portion of the ink holding chamber 72. The gas-liquid interface of the ink in the chamber 72 is broken, the ink in the ink supply liquid chamber 71 is consumed, and the atmosphere is replaced by the ink holding chamber 72 by the ink consumption amount. The relationship between the remaining amount of ink and the back pressure here can be expressed by the slope of B-C in FIG. 13, and the back pressure rises up to a slight back pressure fluctuation when the atmosphere is replaced with ink, that is, until the gas-liquid interface is broken. The back pressure after fracture is low. However, the back pressure of the ink tank 74 remains substantially constant.

When the ink in the ink holding chamber 72 is completely consumed, the ink remaining in the ink supply liquid chamber 71 is consumed. The relationship between the back pressure and the remaining ink amount at this time is shown in FIG.
Can be expressed by the inclination of the CD section, and the head pressure of the ink holding chamber 72 is completely absent, and the balance between the capillary force of the negative pressure generating member 70 and the head pressure of the ink supply liquid chamber 71 is expressed. , The back pressure changes rapidly with respect to the remaining amount of ink.

That is, the back pressure change from when the ink tank 74 is used to when ink cannot be supplied is very large.
When high-speed printing is performed, a large obstacle to ink supply to the head, that is, the meniscus of the ink ejection hole greatly changes with respect to the remaining ink amount, and the ink ejection amount from the beginning to the end of use of the ink tank 74 greatly changes. as a result,
The image quality formed on the paper surface is extremely deteriorated. Further, since the ink supply hole 76 holds the ink only by the negative pressure generating member 70, if a shock is applied from the outside with the ink tank removed from the head portion, ink leakage easily occurs, and further ink supply is performed. If the ink in the ink holding chamber 72 near the communication passage 73 on the liquid chamber 71 side is completely cut off, the ink cannot be supplied despite the presence of the ink in the ink holding chamber 72.

[0015]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an ink tank having a good ink holding performance.

[0016]

An ink tank of the present invention comprises an ink supply liquid chamber for supplying ink to a print head,
An ink tank having an ink holding chamber, which internally communicates with an ink supply liquid chamber at a lower portion and holds ink, and which has an atmosphere communicating hole provided in the ink holding chamber so as to communicate with the atmosphere. A capillary member is provided in the ink supply section.

[0017]

According to the first aspect of the invention, the ink contained in the ink tank can be efficiently supplied to the recording head with a lower back pressure and less back pressure fluctuation, and the ink supply for high speed printing of the head is insufficient. Can be resolved.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an ink tank according to an embodiment of the present invention. In FIG. 1, the recording head 50, the head block 63, and
The connection state of the ink tank 19 and the carriage 14 is shown. The recording head 50 according to the present embodiment uses an ink itself, which is a resistor, as an actuator for generating bubbles, and uses an electrode that energizes the ink according to an electric signal to generate thermal energy for causing a boiling phenomenon in the ink itself. It is an energized bubble jet system that records by recording.

In FIG. 1, the recording head 50 is located on the head block 63, and the positioning grooves 57 provided in the head block 63 in the vertical, horizontal, and rotational directions are fitted and inserted into the positioning projections 56 of the carriage 14.

The electrodes for supplying electric power to the ink and the electric wiring are formed into a plurality of rows on the glass substrate by a known method such as sputtering, vapor deposition, ion plating, etc., and a desired pattern is formed by etching. Formed. The wiring of the flexible substrate 53 fixed on the aluminum plate 51 for heat dissipation, which has the pad portion 68 for receiving an electric signal, is connected to this pattern by wire bonding or TAB bonding.

The flexible substrate 53, to which the glass substrate is connected, is positioned and inserted into the protrusion 52 of the head block based on the positioning hole 55 on the flexible substrate 53, and the ink flow passage 62 of the head block 63 and the flow passage on the glass substrate. Are sealed and joined with an adhesive such as epoxy or silicon.
A filter 61 is provided at the ink inlet port 58 of the head block 63 on the ink tank 19 side to prevent dust and extra bubbles from entering the recording head 50.

From the ink tank 19 to the head block 6
The ink that has passed through the third ink flow path 62 and the flow path on the glass substrate has a common liquid chamber laser-processed on polyimide, a plurality of ink flow paths corresponding to a pair of electrodes required for boiling, and ink ejection holes. The polyimide, which is supplied in this order and processed into a flow path, is bonded onto a glass substrate with a thermosetting adhesive or the like to form an ink discharge flow path.

The ink tank 19 includes a left and right ink tank positioning groove (not shown) of the carriage 14 and the carriage 1.
4 is pressed toward the head block 63 side by a leaf spring 65 provided to press the ink tank 19 against the head block 63. At this time, the capillary member 61-1 provided in the ink tank 19 and the filter 61 of the head block 63 are pressure-bonded to each other, and the ink inflow hole portion of the head block 63 and the ink supply hole 58 of the ink tank 19 are further connected.
The -1 joint is completely coupled and sealed by an elastic body 59 provided at the ink inlet 58 in order to prevent the invasion of the atmosphere from the both joints.

As described above, in the present embodiment, the replacement ink tank 19 is facilitated, bubbles can be prevented from being mixed from the joint portion of the ink tank 19 and the head block 63, and the replacement can be reliably carried out. Can be improved.

Here, the arrangement and operation of the recording head 50 in the ink jet recording apparatus in this embodiment will be described with reference to FIG.
The horizontal printing posture will be described below.

In FIG. 2, the recording medium 1 is fed from the lower side to the upper side of the platen 21 by the pickup roller 11, and the recording medium 1 is fixed to the platen 21 by the paper presser 10 that presses in the moving direction of the carriage 14.

The carriage 14 includes a carriage guide 20 and a cage shaft 18 arranged parallel to the printing surface.
Is fixed to a part of a timing belt 23 that is connected to a pulley 7 and a drive pulley 17 that are rotatably supported by a main frame 22, and is moved in the left-right direction with respect to the recording medium 1 fed from a pickup roller 11. Move back and forth.

The timing belt 23 is driven by the drive motor 15 via the drive pulley 17 and is driven in conjunction with the forward and reverse rotation of the drive motor 15.

Reference numeral 8 is a photocoupler, which is a carriage 14.
Carriage 14 at any position near photo coupler 8
The home position detecting means detects the protrusion 13 and switches the rotation direction of the drive motor 15.

The image recording signal is sent to the recording head 50 in synchronism with the movement of the carriage 14 carrying the recording head 50, and ink droplets are ejected at a predetermined position on the recording medium 1 for recording.

Reference numeral 5 is a member for supporting the cap member 6, and the ink ejection portion of the recording head 50 is clogged with dried ink through the opening in the cap, and the ink in the ink tank 19 is supplied to the ink ejection portion. The suction recovery of the recording head 50 for the purpose is performed.

Reference numeral 9 is a cleaning blade, and 4 is a member that enables the cleaning blade 9 to move vertically with respect to the recording head 50. Reference numeral 3 denotes a cam gear drivingly connected to each of the support members of the cap support member 5 and the cleaning support member 4 for performing suction recovery, cleaning operation, and the like at a predetermined position. The cam gear 3 is provided on the main body support plate 24 separately from the carriage motor 15. It rotates in conjunction with the rotation of the supported motor 2. The suction operation, the blade operation, and the like need not be in this form, and may be a conventionally known method. Suction recovery,
The timing of the blade operation is configured such that when the carriage 14 reaches the home position side area, the photo coupler 8 detects the home position detection signal, and the rotation operation of the motor 2 is controlled at a predetermined timing by a desired process. ing.

Next, the ink tank of this embodiment will be described in detail. (First Embodiment) FIG. 3 is a configuration diagram of an ink tank according to the first embodiment of the present invention.

The ink tank 80 is divided into an ink supply liquid chamber 100 and an ink holding chamber 101 by a partition rib 102, and the ink supply liquid chamber 10 is located below the partition rib 102.
A communication hole 105 is provided so that 0 and the ink holding chamber 101 communicate with each other.

The ink holding chamber 101 includes the negative pressure generating member 10
3 is compressed and enclosed with almost no space, and the ink holding chamber 101 is communicated with the atmosphere by the atmosphere communicating hole 104 provided in the upper portion.

The ink supply liquid chamber 100 is filled with ink without any gap, and the capillary member 6 is provided in the ink supply hole 58-1.
1-1 is hermetically sealed and inserted, and the ink supply liquid chamber 100 is in a substantially simple hermetically sealed state.

FIG. 4 shows the initial state of ink filling. The ink supply liquid chamber 100 is filled with ink without a gap, and the negative pressure generating member 103 near the atmosphere communication hole 104 of the ink holding chamber 101 absorbs the ink absorbed by the negative pressure generating member 103 above the negative pressure generating member 103. In order to ensure that the ink is consumed evenly in the direction of gravity within the range of the projection surface, the ink unfilled portion 1
06 is formed.

At this time, the negative pressure inside the ink tank 80 is
The water head pressure of the ink supply liquid chamber 100, the capillary force of the negative pressure generating member 103 and the water head pressure of the ink holding chamber 101 are substantially balanced, and the negative pressure of the ink tank 80 is slightly negative.

Next, the ink consumption process will be described with reference to FIGS. When ink is supplied to the recording head 50 from the initial ink filling state as shown in FIG.
The ink held in the negative pressure generating member 103 of No. 1 starts to be consumed, and the head position of the ink holding chamber 101 decreases as shown in FIG.

Here, A'in FIG. 5 shows the initial ink filling position, in which the ink in the ink holding chamber 101 is consumed as much as possible and the ink holding chamber 101 is in communication with the atmosphere. At this time, the negative pressure of the ink tank 80 can be expressed by the model diagram of FIG. 7, and the fine hole diameter r1 = the communication hole diameter or the fine hole diameter radius of the negative pressure generating member 103, and the fine hole diameter r2 = the capillary member 61- of the ink supply unit When the maximum hole radius is 1, the tank has a relationship of r1 >> r2. The head of ink is h, the density of ink is ρ, the surface tension of ink is γ, the contact angle between the ink container or the negative pressure generating member and the ink. Is represented by θ, r
It may be 1 = 2γCOSθ.

A desired back pressure can be set by reducing the radius r1, that is, the diameter of the communication hole 105 or the pore diameter radius of the negative pressure generating member 103 so that the above relationship holds.

Further, when the ink is consumed, the meniscus formed in the communication hole 105 is curved toward the ink supply liquid chamber 100 side, and when the ink is further supplied, the air in the ink holding chamber 101 is changed to the ink at the same time when the meniscus is broken. Will be replaced.
The negative pressure of the ink supply liquid chamber 100 slightly increases and decreases by the change of the meniscus.

In the position C'in FIG. 6, the ink supply liquid chamber 1 is
In 00, the state is before the replacement of the ink with the atmosphere is started. C '
When the ink is further supplied from the state described above, the replacement of the ink with the atmosphere is repeated and the negative pressure of the ink tank is maintained in a substantially constant state, and the ink is supplied until all the ink in the ink supply liquid chamber 100 is consumed as shown in position D ′. It

Here, the relationship between the negative pressure change in the ink tank 80 and the ink remaining amount will be described with reference to FIG. 8'of FIG.
5 shows a state where the ink in FIG. 5 reaches the position A ′, and the position B ′ where the back pressure is reduced corresponds to the position B ′ where the ink is consumed in the ink holding chamber 101 in FIG. This change means that the back pressure is increased by the amount of the decrease in the head pressure of the ink holding chamber from the state in which the head pressure of the ink supply liquid chamber 100, the capillary force of the negative pressure generating member 103, and the head pressure of the ink holding chamber 101 are balanced. doing.

Further, the positions of C'and D'in FIG. 8 show the positions of C'and D'in FIG. 6, and the head pressure of the ink holding chamber 101 and the meniscus of the communication hole 105 are in balance with each other.
Ink tank 80 by replacing the atmosphere with ink each time the ink decreases
Back pressure is generally constant.

Here, since the head pressure of the ink supply liquid chamber 100 does not decrease until all the ink in the ink holding chamber 101 is supplied, the change in ink back pressure is smaller than that in the conventional improved divided ink chamber system. In particular, in order to prevent ink leakage due to an external impact in the initial state of ink filling of the ink tank 80, if the capillary force of the negative pressure generating member 103 is increased, the back pressure change from the start of ink use to the end of ink supply is conventionally changed. Can be significantly reduced compared to the method of.

(Second Embodiment) In the second embodiment, in the ink tank system of the first embodiment, the capillary member 61-1 of the ink supply section holds the ink in the ink supply liquid chamber 100, The mixture of foreign matter and air from the outside is prevented, and in particular, the ink from the ink holding chamber 101 is supplied to the ink supply liquid chamber 100 before the ink leaks from the ink supply hole 581 due to the impact from the outside. Therefore, the reliability is further improved by using the fibers obtained by bundling the fibrous polyester fibers 110 shown in FIG. 10 and sealing and curing the surface layer with the thermosetting adhesive 111.

A metal filter having a maximum filtration particle size of about 10 μm, which is formed by twilling a wire material having a wire diameter of about 30 μ such as SUS316, may be used. Further, a material having extremely high water repellency with respect to the used ink is more preferable.

In general, the negative pressure generating member 80 is formed by foaming a main component of polyether polyol, toluene diisocyanate, a tertiary amine and silicone as a foam stabilizer by an explosion method using oxygen and hydrogen. After performing the film removal treatment, a multi-communicating ether foaming polyurethane having pores 120 as shown in FIG. 12 is used.
And the number of cells (hole 1 per inch that has been removed)
The number of 20) and the wettability of the material and the ink define the capillary force.

Here, with respect to the number of the holes 120, the negative pressure value of the tank, the insertability of the negative pressure generating member, the ink filling efficiency (ratio of the ink supply amount to the ink filling amount), the ink leakage amount with respect to the impact from the outside. 11
As shown in, we have found that there is a relationship between the number of cells and the capillary force.

Especially regarding the ink filling efficiency, the number of cells is 6
In the negative pressure generating member 103 of 0 or more, the skeleton 121 forming the pores 120 becomes thick, the residual film around the bone angle after the film removal treatment is remarkably generated, and the retained ink remains in the residual film, and eventually the retained film remains. Although much ink still remains in the ink holding chamber 101, the ink is cut off and the atmosphere is communicated.

If the number of cells of the negative pressure generating member 103 of the ink holding chamber 101 is approximately 100 or less, the negative pressure value of the ink holding chamber 101 can be suppressed to a small value, but the ink is interrupted by an external impact or the like. However, if the pressure is about 200 or more, the negative pressure value becomes high and ink leakage due to an external impact is less likely to occur.
Although the ink contained in the negative pressure generating member 103 remains, the atmosphere is introduced from the boundary between the negative pressure generating member 103 and the inner wall of the ink tank 80.

That is, when the ink tank is used, the range of use of the number of cells of the negative pressure generating member 103 is 60 or less, and the apparent number of cells of the negative pressure generating member inserted in the ink tank is 100 or more. It is preferable to adopt the condition of 200 or less.

[0054]

The ink tank of the present invention is an ink holding chamber having an ink supply liquid chamber for supplying ink to a print head and a negative pressure generating member communicating with the ink supply liquid chamber at a lower portion for holding ink therein. And an ink tank having an air communication hole provided in the ink holding chamber so as to communicate with the atmosphere, and since a capillary member is provided in the ink supply unit, it is possible to reduce the back pressure change of the entire ink tank and It is possible to stabilize the ink supply during printing and the meniscus of the ink ejection holes.

[Brief description of the drawings]

FIG. 1 is a sectional view of an ink tank according to an embodiment of the present invention.

FIG. 2 is a perspective view of a recording apparatus according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of an ink tank according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram of an ink tank according to the first embodiment of the present invention.

FIG. 5 is a configuration diagram of an ink tank according to the first embodiment of the present invention.

FIG. 6 is a configuration diagram of an ink tank according to the first embodiment of the present invention.

FIG. 7 is a model diagram showing the principle of replacement of ink with the atmosphere when the ink in the ink supply liquid chamber is supplied in the embodiment of the present invention.

FIG. 8 is a graph showing the relationship between the ink remaining amount and the back pressure in the divided ink chamber ink tank system according to the embodiment of the present invention.

FIG. 9 is a detailed view of a capillary member according to an embodiment of the present invention.

FIG. 10 is a characteristic diagram of the number of cells of the negative pressure generating member and the ink tank according to the embodiment of the present invention.

FIG. 11 is a partial detailed view of the negative pressure generating member according to the embodiment of the present invention.

FIG. 12 is a configuration diagram of a conventional improved type division ink chamber ink tank.

FIG. 13 is a graph showing the relationship between the remaining ink amount and the back pressure in the conventional divided ink chamber ink tank system.

[Explanation of symbols]

 61-1 Capillary member 100 Ink supply liquid chamber 101 Ink holding chamber 103 Negative pressure generating member

Claims (3)

[Claims] 1. An ink supply liquid chamber that supplies ink to a print head, and an ink holding chamber that accommodates a negative pressure generating member that communicates with the ink supply liquid chamber at a lower portion and holds ink therein.
An ink tank having an atmosphere communication hole provided in the ink holding chamber so as to communicate with the atmosphere, wherein the ink supply section is provided with a capillary member. 2. The ink tank according to claim 1, wherein the capillary member is composed of a polyester fiber and a surface-cured fiber cured with a thermosetting adhesive or a woven stainless steel filter. . 3. The number of cells of the ink holding member (the number of holes per inch) is 60 or less, and the apparent number of cells is 100 to 200.
The described ink tank.