JPH06320745A - Ink tank, head cartridge integrally constituted of ink tank and printing head and ink jet printer - Google Patents

Abstract

PURPOSE:To obtain an ink tank structure capable of well supplying ink to a printing head performing high frequency emitting driving when melamine foam is used as the ink absorbing member of the ink tank used in an ink jet printer. CONSTITUTION:The longitudinal length (c) of the melamine foam 12 received in an ink tank housing 11 is made larger than the longitudinal length C of the housing 11. By this constitution, the foam 12 is compressed in the direction of the ink supply port 13 to a printing head 14, that is, in an ink supply direction in the state received in the housing. As a result, in the melamine foam 12, ink holding force by capillary force is not increased in the compression direction and an ink supply property can be enhanced and the ink holding force in the direction crossing the compressed direction at a right angle is increased to enable predetermined ink holding.

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 ink tank integrated head cartridge in which the tank and an ink jet print head are integrally formed, and an ink jet printing apparatus including the ink tank or the head cartridge. In particular, the present invention aims to improve the configuration in which an ink holding absorber is provided in the ink tank.

Printing includes ink application to all ink supports that receive various inks such as cloth, thread, paper, and sheet material, and includes all types of information processing devices or printers as output devices thereof. However, the present invention can be applied to these.

[0003]

2. Description of the Related Art Conventionally, many absorbers contained in this type of ink tank are made of urethane resin foam. When such a urethane foam is formed, a film is formed so as to include a cavity (pore) at the time of its formation, and a large number of pores are isolated from each other, so that they can function as an absorber for ink impregnation. Heating,
Film removal treatment such as washing is performed.

However, when the urethane foam is used as an absorber in the ink tank, the urethane foam is stored in a compressed state in the storage space of the ink tank, or it is suitable at the communicating portion with the ink lead-out connection member. Although that part may be compressed due to the provision of the negative pressure gradient, it is extremely difficult to completely remove the film even by the above film removal treatment, and in reality, a considerable amount of film residue is attached to the pores. For this reason, the residue of the film complements between adjacent pores during compression, which hinders the ink flow inside the absorber that should occur as ink is consumed, that is, the ink supply to the outside of the ink tank is reduced. May cause trouble.

[0005]

[Related Art] On the other hand, an absorbent body made of a foam made of a melamine-formaldehyde condensate which is completely different from such a urethane foam is an international publication number WO91 / 0265.
No. 4,501,392 corresponding to No. 2 is proposed. Since the absorbent body has an inherently net-like structure, which is formed of a completely skeleton network in which no thin film exists in the gaps of the foam network, it does not require film removal treatment, Since the fibers that make up the circuit network are fine, it is possible to fill a larger amount of ink than urethane foam, and the initial filling of ink because it is water-repellent to urethane foam that exhibits water repellency. Advantages such as easy processing, ink is not left behind by the film or its residue like urethane foam when ink is consumed because it does not originally have a film, and therefore ink can be used up efficiently. have.

[0006]

However, it is said that the absorber made of the melamine-formaldehyde condensate disclosed in the above-mentioned publication is basically preferably used in an uncompressed state. Ink is supplied to the ink lead-out section provided in the. That is, since the ink supply direction to the ink lead-out portion is fixed only to the lower side in the vertical direction, there is a problem that the posture when the ink tank is used is limited. Further, when it is in a preferable uncompressed state, it is difficult to bring the absorber into close contact with the inner wall of the storage part, and therefore, a gap is created between the absorber and the inner wall of the storage part, so that the space is provided in the storage part. When the air taken in from the atmosphere communication port or the ejection port of the ink head stays in the void, air bubbles are mixed in the ink supplied to the ink head as the ink is ejected, and the quality of recording is remarkably increased. Will be disturbed. In particular, in an apparatus of a form in which an ink tank portion and an ink head are integrated and printing is performed by reciprocally scanning the integrated product with respect to a print medium or the like, the ink tank portion is shaken by the reciprocal scanning. Such problems are likely to occur. In addition, if there are effects of such vibrations,
When there is a member that comes into contact with the absorber in the vicinity of the ink lead-out portion, deterioration of the absorber with time occurs in the vicinity of the ink lead-out portion, and there is a risk that voids may be formed there.
It is conceivable that the adverse effect due to the retention of air will become more significant. In a further severe case, it is predicted that the atmosphere communication port and the void near the outlet part will communicate with the atmosphere, and if such a situation occurs, not only the desired ejection operation becomes impossible, but also the ink supply path. The ink existing in the ink will leak from the ink discharge port and stain the inside of the apparatus.

Further, since the ink is supplied to the ink outlet by utilizing the effect of gravity, if the print head or the like is driven at a high frequency which is particularly desired recently, there is a possibility that the ink supply cannot follow this. . Therefore, it is conceivable to increase the pore size to some extent and reduce the flow resistance in order to improve the followability, but in this case, the ink holding capacity of the absorber decreases and ink leakage from the atmosphere communication port etc. occurs. There is a risk.

In the above publication, while maintaining the useful or preferable characteristics in the uncompressed state, the gap space of the structure is adjusted.
Therefore, it is said that the compressive force may be desirable in a specific application example for the sake of convenience.
Line to line 21).

It is considered that the above description is made by paying attention to the balance between the inner size of the storage space and the outer size of the absorber, but the present inventors have found the advantage of the absorber made of the melamine-formaldehyde condensate. It has been found that, while making good use of it, it is sufficient to appropriately compress and use the absorber for smooth and reliable ink supply regardless of the posture of the ink tank. However, the inventors of the present invention should perform compression in an appropriate direction in order to perform smooth supply corresponding to the structure of the absorbent body, and the absorbent body has a so-called "" They have also found technical problems such as "sagging" or destruction may occur, and if "sagging" occurs, the compressed state cannot be maintained and the above-mentioned problems may occur in the same manner as the non-compressed state.

In addition, a filter for removing foreign matter is generally provided at the ink outlet portion from the absorber, and the opening area of the outlet portion is determined according to the desired supply amount. However, the thermosetting melamine condensate has a structure. It was also found as a technical subject that peeling may occur during processing, storage, or subsequent use due to its brittleness, and the peeled pieces may clog the filter, making it impossible to maintain a desired supply amount.

None of these technical problems has been suggested in the above publication, and the present invention provides a condensation product of a compound having an amino group and a formaldehyde in the form of a porous body having a three-dimensional network structure. The present invention aims to solve at least one of the above-mentioned technical problems while utilizing the advantages of an absorbent body made of a foam based on.

[0012]

Therefore, according to the present invention,
As an ink tank configuration, in an ink tank for storing ink, a housing provided with a supply port for supplying the stored ink, and an ink absorber housed in the housing to hold the ink Which is a porous body having a three-dimensional network structure, and an ink absorber made of a foam based on a condensation product of a compound having an amino group and formaldehyde, and the ink absorber to the supply port. And a compressing means for compressing toward.

Further, in the ink tank for storing the ink, a housing provided with a supply port for supplying the stored ink, and an ink absorber housed in the housing to hold the ink And
An ink absorber made of a foam based on a condensation product of a compound having an amino group and formaldehyde, which is a porous body having a three-dimensional network structure, and the ink absorber is at least one direction inside the housing. And a compressing means for compressing.

More preferably, the ink absorber for holding the ink contained in the housing is a foam having less cell membrane than the urethane resin foam or a condensation product of a compound having an amino group and formaldehyde. The base foam is characterized by having a storage foam deformation storage mechanism for compensating or suppressing the characteristic deterioration of the ink absorber.

Further, the ink absorber for holding the ink contained in the housing is based on a condensation product of formaldehyde and a foam having less cell membrane than the urethane resin foam or a compound having an amino group. It is a foam, and is characterized in that at least a part of the ink absorber housed in the housing and holding the ink is subjected to a pretreatment for compensation.

Further, at least the ink supply side surface or the sliding surface at the time of loading of the ink absorber is shaped by water jet processing.

In a head-integrated cartridge structure, the head cartridge integrally includes a print head for ejecting ink and an ink tank for storing ink to be supplied to the print head, and the ink tank is stored. A housing provided with a supply port for supplying ink, and an ink absorber housed in the housing for holding ink, which is a porous body having a three-dimensional network structure and has an amino group It is characterized in that it has an ink absorber made of a foam based on a condensation product of the compound and formaldehyde, and a compression means for compressing the ink absorber toward the supply port.

Further, in a head cartridge integrally provided with a print head for ejecting ink and an ink tank for storing ink to be supplied to the print head, the ink tank supplies the stored ink. A housing provided with a supply port, an ink absorber housed in the housing for holding ink, a porous body having a three-dimensional network structure, and a compound having an amino group and formaldehyde. An ink absorber comprising a foam based on the condensation product of
Compression means for compressing the ink absorber in at least one direction inside the housing.

In the ink jet printing apparatus, a print head for ejecting ink is used, and in the ink jet printing apparatus for performing printing by ejecting ink from the print head to the printing material, the ink to be supplied to the print head is supplied. An ink tank for storing, a housing provided with a supply port for supplying the stored ink, and an ink absorber housed in the housing for holding ink, An ink absorber which is a porous body having an original network structure and which is a foam based on a condensation product of a compound having an amino group and formaldehyde, and compression for compressing the ink absorber toward the supply port Means and
It is characterized by comprising an ink tank having.

Further, in an ink jet printing apparatus that uses a print head for ejecting ink and ejects ink from the print head onto a printing material to print, ink for storing ink to be supplied to the print head. A tank, a housing having a supply port for supplying the stored ink, and an ink absorber housed in the housing for holding the ink, having a three-dimensional mesh structure An ink absorber made of a foam which is a porous body and is based on a condensation product of a compound having an amino group and formaldehyde; and a compression means for compressing the ink absorber in at least one direction inside the housing. And an ink tank having.

[0021]

With the above construction, the foam forming the ink absorber in the ink tank is compressed in the direction of the supply port, so the size of the foam pore facing this direction does not change,
The pore size in the direction perpendicular to the compression direction is reduced. Here, if the pore size is made large in advance, the capillary force in the compression direction, that is, the direction toward the supply port can be relatively weak and can be made strong in the vertical direction. As a result, it is possible to improve the ink supply property by reducing only the holding force in the ink supply direction while maintaining the predetermined ink holding force.

Further, since the ink absorber is stored in the housing in a compressed state, the absorber and the housing can be kept in close contact with each other at all times, and in particular, the absorber is brought into close contact with the ink supply port. No gap such as an air layer is created in the ink supply path.

[0023]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(First Example) The melamine foam used as an ink absorber in this example is a porous body having a three-dimensional network structure and is based on a condensation product of a compound having an amino group and formaldehyde. 1 of the foam
Is one. Such a foam generally has a three-dimensional network structure formed by relatively fine single fibers and has no cell wall (membrane). Single fibers have a relatively large length relative to their width. As a result, the volume ratio of the cavity of the cell (hereinafter, also referred to as pore) is high, the volume density of the foam is small, and the porosity is large. The pore size is relatively uniform and the proportion of pores of significantly smaller size than the average pore size is relatively small. In order to preferably use the foam of this example, the porosity is 95% or more, the volume density is 0.024 g / cm or less, and the average pore size is 20.
It is preferably 0 μm or more, and such a foam can be manufactured by a known method.

In an embodiment of the invention, the foam is compressed at least in the direction of the supply port for supplying ink to the printhead.

This will be described in more detail below. The print head has a relatively high frequency (3 kHz or more) due to high-speed recording of inkjet printing devices.
Therefore, the amount of ink ejected from the orifice increases within a unit time. In this case, an optimum image cannot be formed when the ink in the ink tank is not supplied to the print head following high frequency driving.

On the other hand, in this example, by increasing the pore size of the melamine foam, the capillary force is reduced and the flow resistance of the ink in the foam is reduced. However, when the capillary force decreases, the amount of ink that can be held without causing ink leakage decreases, and the number of printable sheets decreases.

This problem is solved by compressing the foam in the ink tank at least in the direction of the ink supply port as described above.

FIGS. 1 (A) and 1 (B) are schematic views showing a part of the melamine foam structure for explaining the compression structure.

FIG. 1A schematically shows the melamine foam 12 before being compressed, and each cell of the foam has a horizontal single fiber 120h and a vertical single fiber 120v in the figure. And has openings 121h and 121v for the respective pores.

In FIG. 1B, the melamine foam 12 is shown in FIG.
(A) shows a state of being compressed in the direction of arrow A. As is clear from the figure, the compression direction (arrow A in FIG. 1A)
The opening 121v facing in the direction perpendicular to the (direction) direction has its opening area reduced by compression, and the opening 121h facing the compression direction does not reduce the area.

In the melamine foam which is in the compressed state as described above, the capillary force has a directional characteristic or is reinforced. That is, when the ink held in the pores tries to move to the supply port side by the action of the negative pressure or the atmospheric pressure on the print head side, the ink holding force by the capillary force acting as a resistance against the ink is Due to the change or invariance of the area, it increases in the direction perpendicular to the compression direction and hardly changes in the compression direction.

As a result, in the ink supply direction, it is possible to obtain the necessary holding force in the other directions while increasing the pore size and decreasing the ink holding force so that the ink can be quickly supplied.

By the way, even if the same compression structure is adopted for the conventional urethane foam, not so remarkable holding force directionality or strengthening occurs. This, as mentioned above,
This is because the thin films that remain on the structural member of the urethane foam and remain unremoved overlap due to the compression, and the area (projected area) of the opening facing the compression direction is also reduced, which also increases the holding force in the compression direction.

FIG. 2 is a schematic exploded perspective view showing the ink tank according to the first embodiment of the present invention.

A print head 14 is connected to the front end portion of the housing 11 of the ink tank. This connection may be configured to be detachable from each other, as is conventionally known, or may be a fixed connection in which the print head 14 and the housing 11 are integrally formed. Further, a supply port 13 for supplying ink from the ink tank to the print head is provided in a part of the connecting portion.
The print head used in this example is one in which thermal energy is applied to ink to generate bubbles and the ink is ejected by the acting force of bubble generation.

The melamine foam 12 forming the ink absorber is housed in the housing 11, and the length C of the housing portion in the ink supply direction is shorter than the length C of the melamine foam 12 in the same direction. ing. Accordingly, when the melamine foam 12 is housed in the housing 11 and covered with the housing lid 15, the melamine foam 12 is compressed in the ink supply direction.

Even when the foam 12 is compressed in the supply port direction in this way, since the pore size of the foam facing the supply direction is not reduced as described above, the capillary force in the ink supply direction does not rise, The ink flow resistance does not increase. On the other hand, since the pore size facing the direction orthogonal to the ink supply direction becomes smaller, the capillary force in the ink supply direction increases and the desired ink holding force can be obtained. As a result, the initial ink filling amount does not decrease, and there is no risk of ink leakage through the atmosphere communication hole 16 or the like.

FIG. 3 is a diagram showing another configuration example of the ink tank, which is the same as FIG.

In the example shown in FIG. 3, thin grooves radially extending from the ink supply port 13 are provided on the inner wall of the front end portion of the housing 11 to promote the movement of the ink to the supply port 13.

The relationship between the pore size of the foam that can be used in this example, the compressibility of the foam for obtaining a predetermined ink holding force, and the ink flow resistance at that time is shown in Table 1 below. Show.

[0042]

[Table 1]

As shown in Table 1, in this embodiment, when a melamine foam having an uncompressed pore size of 200 to 320 (μm) was used at a compression ratio of 1.4 to 2.2, a predetermined ink was used. It is possible to obtain a holding force, that is, an ink holding force that can secure a desired ink filling amount without causing ink leakage, and the ink flow resistance in the compression direction is about 83% or less of that when not compressed (compression rate 1). It becomes possible to do.

Even when the pore size is out of the above range, the pore size which can exert a predetermined effect by the application of the present invention is 150 to 450 (μm) in the uncompressed state.
And more preferably 200 to 400 (μm).

When the pore size is increased within this range, it is possible to secure a certain pore size even if the single fiber is partially damaged, and it is possible to minimize the deterioration of ink supply.

When the pore size is 100 μm or less,
The desired reduction in current resistance cannot be obtained, and high-frequency driving cannot be achieved. Further, in the case of 500 μm or more, the compression rate must be 3 or more in order to obtain a desired ink holding force,
In such a case, not only is it unrealistic in terms of the ink tank structure, but also many single fibers forming the melamine foam may be damaged, which leads to mechanical deterioration of the foam.

Melamine constituting the foam used in this example is a compound having an amino group, and similar compounds include, for example, urea, carboxylic acid amide, dicyandiamide, guanidine, sulfurylamide, sulfonic acid amide, and fat. At least one of the group amine, benzoguanamine and its derivatives can be used. Further, in addition to formaldehyde, at least one of acetaldehyde, trimethylolaldehyde, acrolein, benzaldehyde, furfurol, glyoxal, phthalaldehyde, and terephthalaldehyde may be contained.

The ink absorber formed is a porous body having a three-dimensional network structure, and is an elastic foam based on the condensation product of melamine and formaldehyde, and is described in, for example, US Pat. No. 4,540,717. It can be manufactured by the method described above. More preferably, 80%
It is an elastic foam containing the above melamine-formaldehyde condensate.

As the melamine-formaldehyde condensation product, a compound having another amino group up to 50 to 20% by weight is condensed in addition to melamine, and another aldehyde is condensed up to 50 to 20% by weight in addition to formaldehyde. May be included.

As described above, the settling and the like can be compensated or suppressed. The embodiment of the present invention solves the above-described novel problem by providing a storage foam deformation storage mechanism in the tank by improving the absorber structure itself.

(Second Embodiment) This embodiment is optimal with respect to the melamine foam having the structure of the first embodiment, further considering the material characteristics of the foam, the ink supply direction, the ink holding amount and the like. It is intended to be.

FIG. 4 is an exploded perspective view showing an ink tank according to the second embodiment of the present invention.

In FIG. 4, a melamine foam (hereinafter also referred to as melamine foam) 12 is an ink housing 11.
Is stored in. The opened foam insertion port of the ink housing 11 is closed by a housing cover 15, and an air communication port 16 is opened in the housing cover 15 so that the used ink is replaced with the atmosphere. Print head 14
Ejects ink droplets by the same ejection method as in the first embodiment, and printing is performed on paper or the like. As the print head 14 ejects the ink, the ink is supplied from the ink tank to the recording head through the ink supply port 13 slightly protruding inward, which is in contact with the melamine foam 12 holding the ink, to the recording head.

As shown in FIG. 4, the height, width, and vertical inner dimensions of the ink housing 11 are A, B, and C, and the same dimension of the melamine foam 12 is a, respectively.
When b and c are set, they have the following relationship.

First, c / C indicates the compression ratio in the ink supply direction as shown in the first embodiment, and Table 2 shows the relationship between the compression ratio and the print quality in this embodiment. Shown in.

[0056]

[Table 2]

As shown in Table 2, in the case of this example, the relationship with other dimensions, that is, when the dimensions a and b are compressed, c
Good printing can be performed when / C is 1 or more (1.5 or less).

Secondly, the dimensions a, b and A, B are

[0059]

## EQU00002 ## The relationship of 0.8.ltoreq.a / A.times.b / B.ltoreq.1.7 is satisfied. Table 3 shows data comparing the performances by changing these dimensional ratios (c / C is c / C>
Fixed to a predetermined value of 1.0). That is, the inner dimensions of the ink housing 11 are A = 3 cm, B = 2 cm, and C =, respectively.
It was fixed at 4.5 cm and the dimensions a and b of the melamine foam were changed.

[0060]

[Table 3]

In Table 3, the usable ink amount is

[0062]

[Equation 3] (Usable ink amount) = (Injectable ink amount) − (Remaining amount of ink)

In Table 3, when the product a / A × b / B is smaller than 0.8, the volume of the foam 12 itself is considerably reduced, and accordingly, the amount of ink that can be initially held is reduced, and as a result, the ink can be used. The amount of ink decreases. If this value is set to be larger than 1.75, the ink holding power of the foam 12 becomes large and the ink supply property is deteriorated to make it unsuitable for high frequency driving, and it becomes difficult to supply the ink to the print head 14. The remaining amount of ink increases and the amount of usable ink decreases.

Next, regarding the print density and the quality, when the product is larger than 2.0, the ink supply property similarly decreases and the print density becomes thin.

The dust shown in Table 3 at the time of storage is due to the fact that melamine foam is relatively hard and brittle, and is generated by rubbing between the melamine foam 12 and the ink housing 11 during and after storage. It is a scraped piece of.

In order to prevent the foam from being damaged during and after storage of the melamine foam 12, a surfactant and a lubricant may be added to the inner wall of the ink tank housing and the outer wall of the melamine foam.

That is, the present invention solves the above-mentioned problems and various types of ink tank housings and / or foams are used to prevent damage to the foams or to compensate or suppress deterioration of the properties of the foams. Treatment, for example, to provide the sliding surface with slipperiness when the foam is stored in the case, or to improve the cut surface to prevent damage to the foam itself due to sliding, and further A treatment for compensating the ink absorber, which is represented as a decrease (including any of those for imparting water repellency to the hydrophilic foam to achieve strengthening of its structure, improvement of durability, etc.) be able to.

As the pretreatment, it is preferable to add a surfactant, a lubricant, a water repellent and the like.

As the surfactant, any of anionic, positive ink, amphoteric and nonionic surfactants can be used, and fluorine-based surfactants can also be used.

Further, it is possible to use a general lubricating oil as a lubricant, and for example, dibasic acid ester, silicone and the like can be preferably used. Further, graphite, molybdenum disulfide, talc can be used as a solid substance, and grease can be used as a semisolid substance. Examples of the water-soluble lubricant include polyethylene glycol and the like, which are suitable because they have little influence on the ink used. It should be noted that water and the ink itself used can also serve as a lubricant.

As the water repellent, those of a relatively high molecular type with the above-mentioned surfactant correspond, and a fluorine-containing high molecular compound is preferable.

By processing at least the foam surface facing the supply port side of the ink tank housing with a water jet, the generation of dust and the like can be significantly reduced and a suitable print can be obtained.

From the data shown in Table 3 above, the effective inner dimensions of 11 of the ink housing of this example are A,
When the outer dimensions of B and foam 12 are a and b, respectively, the dimension ratio is

[0074]

## EQU00004 ## The respective dimensions are defined so as to satisfy the relationship of 0.8.ltoreq.a / A.times.b / B.ltoreq.1.7.

FIG. 5 shows a comparative example of this embodiment, and shows a case where the urethane foam 22 is used as an absorber and the volume is compressed when it is housed in the ink housing 21 (compression rate). 3-5).

The reason why the compression rate is increased in this way is to ensure reliability against ink leakage and the like, and in general, the urethane foam 22 having a small ink holding force in a non-compressed state.
To reduce the internal pore size to increase the capillary force against the ink and achieve the desired ink holding force.

On the other hand, when the melamine foam is used as in this example, as described above, the melamine foam is more hydrophilic than the urethane absorber even if the compressibility is not increased. It becomes possible to have holding power.

FIG. 6 shows an example in which the function of the embodiment shown in FIG. 4 is further improved, and a rib 67 extending toward the ink supply port 63 side is formed on the inner wall of the ink housing 61.
A plurality of are provided. As a result, the atmosphere communication passage is secured to the innermost portion of the tank, and the replacement of the ink held by the melamine foam 62 and the atmosphere flowing in from the atmosphere communication port 66 with the consumption of ink can be further stabilized. In this case, the substantial height dimension of the ink housing 61 is A in the figure (the distance between the tips of the ribs 67). Also,
By providing the ribs 68 on the housing lid 65, it becomes easier for air to enter from the outside to the inside of the ink housing 61.

As described above, as shown in the second embodiment, the ink absorber is housed in the housing in a compressed state in at least one direction, and the compression rate is appropriately determined so that the initial ink filling amount and the ink supply property are simultaneously obtained. This is satisfactory, and damage to the melamine foam due to rubbing against the housing can be reduced.

(Modification 1 of Embodiment 2) FIG. 7 is an exploded perspective view showing an ink tank configuration according to a modification of the second embodiment.

In FIG. 7, the melamine foam 32 is configured such that when it is stored, the dimension a2 of the portion far from the ink supply port 33 is made smaller than the dimension a2 of the portion farther from the ink supply port 33, and the dimension between them has a gradient. As a result, the cell size distribution of the foam 32 is forcibly formed so as to become smaller toward the ink supply port 33 side during storage. As a result, the ink holding force becomes stronger on the ink supply side, and the ink supply to the print head 34 is stabilized.

On the contrary, the same effect can be obtained by changing the inner dimension of the ink housing 31 so as to be smaller on the ink supply side.

(Modification 2 of Embodiment 2) FIG. 8 is an exploded perspective view of another modification of the second embodiment.

In FIG. 8, the melamine foam 42 is provided therein with a hole 47 extending from the atmosphere communication port 43 toward the ink supply port 43. As a result, the lattices (fibers) forming the cells of the melamine foam 42 are separated, and the portion where the pore size becomes large is forcibly formed.
As a result, the ink supply to the print head 44 is stabilized. The hole 47 extends from the atmosphere communication port 43 to the ink supply port 4
The reason for extending toward 3 is that the ink moves through the portion of the hole 47 and facilitates the movement of the ink toward the ink supply port 43.

FIG. 10 shows the degree of improvement in variations in print density between manufacturing lots before and after punching. According to this, it is understood that the concentration variation after forming the holes 47 is reduced.

(Modification 3 of Embodiment 2) FIG. 9 shows still another modification of the second embodiment.

In FIG. 9, the melamine foam 52 is provided inside with a slit 57 extending from the atmosphere communication port 56 toward the ink supply port 53. This allows
The lattice forming the cells in the melamine foam 52 is cut off, and the pore size of this slit portion is forcibly formed to be large, as in the above modification. This stabilizes the ink supply to the print head 54.

In each of the above embodiments, the improvement of the adhesion for preventing the separation of the adhesion areas mentioned above,
An elastic pressurizing means such as a spring (coil, plate) or the like may be provided for maintaining the foam in the tank.

FIG. 11 shows an embodiment of an ink jet device to which the head cartridge shown in each of the above embodiments can be applied.

Here, 109 is a head cartridge in which an ink tank and a print head are integrated, and 111 is a carriage for mounting the head cartridge and scanning in the S direction in the drawing. Reference numeral 113 denotes the head cartridge 109 and the carriage 1
Reference numeral 115 is a hook for attaching to 11, and 115 is a lever for operating the hook 113. This lever 115 has
A marker 11 for instructing a scale or the like provided on a cover (not shown) of the printing apparatus so that the print position or set position by the print head of the head cartridge can be read.
7 is provided. 119 is a head cartridge 10
9 is a support plate that supports an electrical connection portion for the connection 9. 121
Is a flexible cable for connecting the electric connection part and the main body control part.

Reference numeral 123 is a guide shaft for guiding the carriage 111 in the S direction, and is inserted into a bearing 125 of the carriage 111. 127 is a timing belt to which the carriage 111 is fixed and which transmits power for moving the carriage 111 in the S direction, and is stretched around pulleys 129A and 129B arranged on both sides of the apparatus. The driving force is transmitted from the carriage motor 131 to one pulley 129B via a transmission mechanism such as a gear.

Reference numeral 133 denotes a carrying roller for controlling the print surface of a print medium such as paper and carrying the same during printing or the like, and is driven by the carry motor 135. Reference numeral 137 is a paper feed tray 104 for the print medium.
Paper pan for guiding the print position from the side 139
Is a feed roller which is disposed in the middle of the feeding path of the print medium to press the print medium toward the transport roller 133 and transport the print medium. Reference numeral 134 denotes a platen that faces the ejection port of the head cartridge 109 and regulates the print surface of the print medium. Reference numeral 141 denotes a paper discharge roller that is arranged on the downstream side of the print position in the print medium conveyance direction and discharges the print medium toward a paper discharge port (not shown). Reference numeral 142 is a spur provided corresponding to the paper discharge roller 141, and the roller 1 is provided via a print medium.
41 is pressed, and the conveyance force of the print medium by the paper discharge roller 141 is generated. Reference numeral 143 denotes a feed roller 139, a holding plate 145, and a spur 1 when setting a print medium.
42 is a release lever for releasing the respective biases.

Reference numeral 145 is a holding plate for suppressing the floating of the print medium in the vicinity of the printing position and for ensuring the close contact with the conveying roller 133. In this example, a print head that prints by ejecting ink is used. Therefore, the distance between the ink ejection port forming surface of the print head and the printed surface of the print medium is relatively small, and the distance must be strictly controlled to avoid contact between the print medium and the ejection port forming surface. It is effective to dispose the holding plate 145. 1
Reference numeral 47 is a scale provided on the pressing plate 145, and 149 is a marker provided on the carriage 111 corresponding to the scale.
With these, the print position and the set position of the print head can be read.

Reference numeral 151 denotes a cap formed of an elastic material such as rubber which faces the ink ejection port forming surface of the print head at the home position, and is supported so as to be able to come into contact with and separate from the print head. This cap 15
1 is used for protection of the print head during non-printing, and for suction recovery processing of the print head. The suction recovery process is performed by causing the cap 151 to face the ejection port forming surface and driving an energy generating element provided inside the ink ejection port and used for ejecting ink to eject ink from all ejection ports. This causes bubbles and dust,
Preliminary ejection processing for removing ejection failure factors such as ink that has become thicker and is no longer suitable for printing), or in addition to this, ink is forcibly ejected from the ejection port while being covered with the ejection port formation surface and the cap 151. This is the process of removing the cause of ejection failure.

Numeral 153 acts as a suction force for forcibly discharging the ink, and at the time of the suction recovery process by the forcible discharge and the suction recovery process by the preliminary discharge, the cap 15 is provided.
1 is a pump used for sucking the ink received. 155 is a waste ink tank for storing the waste ink sucked by the pump 153, and 157 is a tube connecting the pump 153 and the waste ink tank 155.

Reference numeral 159 denotes a blade for wiping the ejection port forming surface of the print head. The blade 159 protrudes to the print head side to perform wiping in the course of head movement, and a retreat that does not engage with the ejection port forming surface. It is movably supported in position and. Reference numeral 161 is a motor, and 163 is a cam device for receiving the transmission of power from the motor 161 to drive the pump 153 and move the cap 151 and the blade 159.

In the first and second embodiments described above, the ink supply port provided in the ink tank is at the center of the predetermined surface of the tank housing.
It goes without saying that the application of the present invention is not applied only to the ink tank of such a form.

That is, when the present invention is applied to a form in which the ink supply port is provided at a deviated position on a predetermined surface of the ink tank housing, by appropriately determining the relationship between the shape of the foam and the housing and the size thereof, For example, the foam may be compressed obliquely toward the ink supply port, or the foam may be compressed along a desired ink path in the ink absorber. You can also

[0099]

As is apparent from the above description, according to the present invention, the foam forming the ink absorber in the ink tank is compressed in the direction of the supply port, so that the foam pores facing in this direction are formed. The size does not change and the pore size in the direction perpendicular to the compression direction decreases. Here, if the pore size is formed to be large in advance, the capillary force in the compression direction, that is, the direction toward the supply port is relatively weak and can be increased in the vertical direction. As a result, it is possible to improve the ink supply property by reducing only the holding force in the ink supply direction while maintaining the predetermined ink holding force.

Further, since the ink absorber is housed in the housing in a compressed state, the absorber and the housing can always be in close contact with each other, and in particular, the absorber is in close contact with the ink supply port. No gap such as an air layer is created in the ink supply path.

As a result, even in an ink tank using a melamine foam or the like as an ink absorber, excellent ink supply can be performed especially in high frequency ejection drive.

[Brief description of drawings]

1A and 1B are schematic views of a foam cell for explaining the principle of the present invention.

FIG. 2 is an exploded perspective view showing the ink tank structure according to the first embodiment of the present invention.

FIG. 3 is an exploded perspective view showing an ink tank structure according to a modified example of the first embodiment.

FIG. 4 is an exploded perspective view showing an ink tank structure according to a second embodiment of the present invention.

FIG. 5 is an exploded perspective view showing an ink tank structure of a comparative example using urethane foam.

FIG. 6 is an exploded perspective view showing an ink tank structure of a modified example of the second embodiment.

FIG. 7 is an exploded perspective view showing an ink tank structure according to another modification of the second embodiment.

FIG. 8 is an exploded perspective view showing an ink tank structure according to still another modification of the second embodiment.

FIG. 9 is an exploded perspective view showing an ink tank structure according to still another modification of the second embodiment.

10 (A) and (B) are diagrams for explaining the effect of the structure shown in FIG.

FIG. 11 is a perspective view of an inkjet printing apparatus that can use the print head of each embodiment of the present invention.

[Explanation of symbols]

11, 31, 41, 51, 61 Ink housing 12, 32, 42, 52, 62 Melamine foam (melamine foam) 13, 33, 43, 53, 63 Ink supply port 14, 34, 44, 54, 64 Print head 15, 35, 45, 55, 65 Housing lid 16, 36, 46, 56, 66 Atmosphere communication port 47 hole 57 Slit 67, 68 rib 120h, 120v Single fiber 121h, 121v opening

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Tokuya Ota 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroshi Sugitani 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Kazuaki Masuda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Jun Kawai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroyuki Ishinaga 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yoichi Tanetani 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tora Kinaga 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (19)

[Claims] 1. An ink tank for storing ink, a housing having a supply port for supplying the stored ink, and an ink absorber housed in the housing to hold the ink. Which is a porous body having a three-dimensional network structure and made of a foam based on a condensation product of a compound having an amino group and formaldehyde; and the ink absorber at the supply port. An ink tank comprising: a compression means for compressing toward. 2. An ink tank for storing ink, a housing provided with a supply port for supplying the stored ink, and an ink absorber housed in the housing for holding the ink. Which is a porous body having a three-dimensional network structure and made of a foam based on a condensation product of a compound having an amino group and formaldehyde, and the ink absorber in the housing. An ink tank, comprising: a compression unit that compresses in at least one direction. 3. The compressing means is characterized in that at least a part of the shape of the ink tank absorber is larger than a part of the shape of the inside of the housing. Ink tank described in. 4. The compound having an amino group is at least one kind of melamine, urea, carboxylic acid amide, dicyandiamide, guanidine, sulfurylamide, sulfonic acid amide, aliphatic amine, benzoguanamine and derivatives thereof. The ink tank according to any one of claims 1 to 3. 5. The ink tank is used in an ink jet print head that performs a printing operation with an ink ejection frequency of 3 kHz or more.
5. The ink tank according to any one of items 4 to 4. 6. A surface parallel to the surface including the supply port of the accommodated ink absorber, wherein A and B are substantially vertical and horizontal inner dimensions of a surface of the housing including the supply port. 2. When the vertical and horizontal external dimensions before storage of a are defined as a and b, the following relationship is established: 0.8 ≦ a / A × b / B ≦ 1.7. Through 5
The ink tank according to any one of 1. 7. The shape of the ink absorber is a /
The ink tank according to claim 6, wherein A and / or b / B is maximum on the surface on the supply port side. 8. The ink tank according to claim 6, wherein a cut slit or hole extending toward the supply port is provided in the ink absorber. 9. The ink tank according to claim 1, wherein a surfactant and a lubricant are applied to a portion where the ink absorber and the inner wall of the housing are in contact with each other. 10. An ink absorber, which is housed in a housing and holds ink, is based on a foam having less cell membrane than a urethane resin foam or a condensation product of a compound having an amino group and formaldehyde. An ink tank, which is a foam and has a storage foam deformation storage mechanism for compensating or suppressing deterioration of the characteristics of the ink absorber. 11. An ink absorber for holding ink contained in a housing is based on a foam having less cell membrane than a urethane resin foam or a condensation product of a compound having an amino group and formaldehyde. An ink tank, which is a foamed body, wherein at least a part of an ink absorber for holding ink contained in the housing is pretreated for compensation. 12. The ink tank according to claim 10, wherein at least an ink supply side surface or a sliding surface at the time of loading of the ink absorber is shaped by water jet processing. 13. A head cartridge integrally comprising a print head for ejecting ink and an ink tank for storing ink to be supplied to the print head, wherein the ink tank supplies the stored ink. A housing provided with a supply port for the ink, an ink absorber housed in the housing for holding ink, which is a porous body having a three-dimensional network structure and having an amino group and formaldehyde. 2. A head cartridge comprising: an ink absorber made of a foam based on the condensation product of <1>, and a compression means for compressing the ink absorber toward the supply port. 14. A head cartridge integrally comprising a print head for ejecting ink and an ink tank for storing the ink to be supplied to the print head, wherein the ink tank supplies the stored ink. A housing provided with a supply port for the ink, an ink absorber housed in the housing for holding ink, which is a porous body having a three-dimensional network structure and having an amino group and formaldehyde. 2. A head cartridge comprising: an ink absorber made of a foam based on the condensation product of <1>, and compression means for compressing the ink absorber in at least one direction inside the housing. 15. The recording head uses the thermal energy to generate bubbles in the ink, and ejects the ink by the action force of the bubbles.
4. The head cartridge according to item 4. 16. An ink-jet printing apparatus that uses a print head for ejecting ink and ejects ink from the print head onto a print material to perform printing, and ink for storing ink supplied to the print head. A tank, a housing provided with a supply port for supplying the stored ink, and an ink absorber housed in the housing for holding the ink, having a three-dimensional mesh structure An ink absorber made of a foam based on a condensation product of a compound having an amino group and formaldehyde, which is a porous body, and a compression means for compressing the ink absorber toward the supply port. An ink jet printing apparatus, which is equipped with an ink tank. 17. An ink-jet printing apparatus that uses a print head for ejecting ink and ejects ink from the print head onto a printing material to perform printing, and ink for storing ink supplied to the print head. A tank, a housing provided with a supply port for supplying the stored ink, and an ink absorber housed in the housing for holding the ink, having a three-dimensional mesh structure An ink absorber made of a foam which is a porous body and is based on a condensation product of a compound having an amino group and formaldehyde; and a compression means for compressing the ink absorber in at least one direction inside the housing. An ink jet printing apparatus comprising an ink tank having: 18. The ejection frequency of the print head is 3
The recording operation is performed at a frequency of kHz or higher.
The inkjet printing apparatus according to 6 or 17. 19. The recording head uses the thermal energy to generate bubbles in the ink, and ejects the ink by the action force of the bubbles.
8. The inkjet printing device according to any one of 8.