KR100503075B1 - Cartridge for ink-jet printing head - Google Patents

Abstract

According to the present invention, a cartridge for an inkjet printing head is disclosed. The inkjet printing head cartridge includes a rigid outer body; A rigid base frame fixed to the outer body; Ink reservoirs formed with holes for supplying and discharging ink, preventing inflow of air and leakage of ink, and fixed to the baseframe; And negative pressure holding means attached to both sides of the ink storage bag and elastically deformed according to the consumption of ink to maintain the negative pressure inside the ink storage bag.

Description

Cartridge for inkjet printing head {Cartridge for ink-jet printing head}

TECHNICAL FIELD The present invention relates to the field of printing engineering, and more particularly, to a printing apparatus, that is, a printer, having an ink-jet printing head including an ink tank therein.

In a known inkjet printer based on the use of a working fluid such as ink, the printing process is performed by supplying ink droplets ejected from the jet of the printing head. Ink is stored inside the ink tank, which protects the ink from drying out and allows the ink to flow evenly to the printing head.

In numerous technical solutions known in the art (see US Pat. No. 5,767,882, US Pat. No. 5,757,406), the cartridge has a rigid body that is relatively hardly deformed relative to the ink tank. The rigid body protects the internal ink tank made of film that ink and air cannot pass through, and serves to secure the cartridge on the carriage of the printer. An ink tank inside the ink tank, which prevents leakage of ink, is provided with an injection hole closed by a plug after injecting ink, a mesh filter, and discharges an appropriate amount of ink toward the jet. A discharge passage is formed. Therefore, the first task, that is, protecting the ink from drying out, is easily solved by introducing an ink tank which prevents the leakage of ink, and the outer body protecting the ink tank from external impact.

The second task is a bit more difficult. In fact, in order to provide a uniform flow of ink, it is necessary to consider factors such as atmospheric pressure, capillary force in the jet of the printing head, the volume of the working fluid, its viscosity, and the like. Intensive research has shown that Hewlett-Packard will maintain a constant pressure drop inside the ink tank, preventing the working fluid from flowing out of control through a capillary jet for optimal operation of the inkjet printing head. We have come to the conclusion that it is necessary to create and maintain a region of depression, ie backward pressure. This is embodied by a system of spiral springs and toggles or a system of leaf springs and toggles.

Similar design is disclosed in US patent N576886. The disclosed cartridge has a twisted spring system that is installed in a rigid frame, is sealed and has an elastic ink tank and a spreader for maintaining return pressure. However, since the ink tank cannot be completely emptied, it is disadvantageous that all stored working fluids cannot be used and difficult to apply industrially due to the complexity of the design in which at least 12 design elements are used.

A further improved design is disclosed in US patent N5757406. The disclosed cartridge has a rigid frame and a flexible ink tank. In the ink tank, a negative pressure is maintained to promote stable flow of the ink as the ink decreases, and to prevent the ink from leaking in the inactive state. In order to perform this function, the flexible ink tank is provided with a pair of leaf springs having a curved shape, that is, a crescent shape, which support the ink tank with the concave sides facing each other and not fixed. The leaf spring makes it possible to keep the required negative pressure level stable. The cartridge thus designed can significantly solve the problem of maintaining the negative pressure inside the ink tank during operation, but the problem remains that the design is complicated because there are at least 15 design elements.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and an object thereof is to provide a cartridge for an inkjet printing head which can not only stably maintain negative pressure inside the ink tank but also improve manufacturability in mass production.

In order to achieve the above object, the cartridge of the inkjet printing head according to the present invention comprises: a rigid outer body; A rigid base frame fixed to the outer body; An ink reservoir bag formed with holes for supplying and discharging ink, preventing inflow of ink and leakage of ink, and fixed to the base frame; And an arch-shaped elastic plate coupled to an outer wall of the ink storage bag and elastically deformed according to the consumption of ink to maintain a negative pressure inside the ink storage bag. It is provided.

The cartridge of the inkjet printing head according to the present invention may further include a reinforcing plate coupled to a portion of an outer wall of the elastic plate to partially reinforce the elastic plate and having elasticity.

In addition, the reinforcing plate is preferably attached only on both ends of the elastic plate, more preferably the center portion may protrude in a wave toward the center portion of the elastic plate.

Moreover, the elastic plate may be formed to a uniform thickness.

In addition, s is a variable defining the position of the elastic plate, Is the radius of curvature of the elastic plate at the position of s, k and n are selected from conditions for providing optimum control characteristics of the pressure operating inside the ink reservoir and are respectively of complete thickness with respect to the elastic plate and the reinforcement plate. Coefficients defining a given contour of change and thickness change, Q is a coefficient that depends on the maximum working pressure inside the ink reservoir and indicates a property that is characteristic of the material and thickness of the reinforcement plate, the elastic plate and the reinforcement plate Is an equation The volume of the inside of the ink reservoir may be changed by deforming accordingly.

Meanwhile, the ink reservoir bag may be formed of at least two film layers. Here, preferably, the inner film layer in contact with the ink is metalized, and the outer film layer to which the elastic plate is attached may be made of thermoplastic material.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view showing an inkjet printing head cartridge according to an embodiment of the present invention, Figure 2 is a side view seen from the "X" direction of Figure 1, Figure 3 is a cross-sectional view taken along the line III-III of FIG. .

Referring to Fig. 1, a cartridge for an inkjet printing head according to a preferred embodiment of the present invention includes an outer body 7 that is rigid (relatively hardly deformed as compared to an elastic ink tank), and the outer body. A rigid base frame (1) fixed to (7) and having an ink inlet (4) for supplying ink and a discharge passage (5) for ejecting ink toward a jet (not shown), An ink reservoir bag 10 fixed to the base frame 1 to prevent leakage is provided.

On both sides of the ink storage bag 10, there are attached negative pressure maintaining means for elastically deforming according to the consumption of ink to maintain the negative pressure inside the ink storage bag 10. The ink injection hole 4 is sealed by a sealing plug 2, and a mesh filter 3 is installed in the discharge passage 5.

As shown in Figs. 2 and 3, the negative pressure holding means includes an arch-shaped elastic plate 6 coupled to the outer wall of the ink reservoir bag 10 and having elasticity, and the elastic plate 6 A reinforcing plate 9 coupled to a portion of the outer wall to partially reinforce the elastic plate 6 and to be elastic.

The ink reservoir bag 10 may be made of a polymer film which cannot pass air or ink, and may be preferably formed of at least two film layers. Here, the inner film layer in contact with the ink is preferably metalized to prevent leakage of the ink, and the outer film layer to which the elastic plate 6 is attached is made of thermoplastic and is easy to weld. It is preferable. This ink reservoir bag 10 is fixed to the base frame 1 by fixing the edge flange 8 to the rigid base frame 1. On the other hand, through-holes (not shown) are formed in the ink storage bag 10 to face the ink inlet 4 and the discharge passage 5. Thus, in the embodiment of the present invention, by using the seamless ink reservoir 10, it is possible to reliably prevent leakage of ink or penetration of air through the ink reservoir 10, so that the ink reservoir 10 ) Can be ensured faithfully.

  The elastic plate 6 may be made of a polymer material having elasticity. This elastic plate 6 is preferably formed in a thin, uniform thickness and has the shape of an arch. This elastic plate 6 is attached on the wide outer wall of the ink reservoir 10 using suitable attachment means (not shown).

Meanwhile, a reinforcing plate 9 for partially reinforcing the elastic plate 6 is attached to a portion of the outer wall of the elastic plate 6. This reinforcing plate 9 may also be made of an elastic polymer material. The reinforcing plate 9 prevents the ink reservoir 10 from collapsing prematurely, and reinforces a portion of the elastic plate 6 so that the negative pressure can be stably maintained in the ink reservoir 10. For this purpose, the reinforcing plate 9 is preferably arranged only on both ends except for the central portion of the elastic plate 6. More preferably, similar to the Greek letter "omega", the central portion of the reinforcing plate 9 may be projected in a wave towards the central portion of the elastic plate 6.

According to the embodiment of the present invention configured as described above, the elastic plate 6 together with the reinforcing plate 9, provides a non-uniform elasticity so that the negative pressure inside the ink reservoir 10 can be stably maintained. do.

The stable negative pressure range to be maintained inside the ink storage bag 10 depends on the control chip provided, and in the embodiment of the present invention, the negative pressure P range within the reservoir is equal to the lower limit P as shown in Equation 1 below. _min ) and an upper limit (P _max ) range, in which the "relatively stable negative pressure" is defined in the range of 250 Pa to 3000 Pa.

P _min <P <P _max , where P _min = 0.97 P _o and P _max = 0.99 P _o .

Where P _o represents atmospheric pressure.

 According to mathematical simulations and experimental results performed to satisfy the negative pressure conditions in the ink storage bag 10 described above, the shape of the reinforcing plate 9 and the curvature of the elastic plate 6 according to the following equation Determined by 2.

here,

s is a variable defining the position of the elastic plate 6 (see FIG. 4),

Is the radius of curvature of the elastic plate 6 at the position of s,

k and n are selected from the conditions for providing an optimum control characteristic of the pressure operating inside the ink reservoir 10, and with respect to the elastic plate 6 and the reinforcement plate 99, respectively, a complete thickness change and a thickness change Coefficients defining a given contour of

Q is a coefficient which depends on the maximum working pressure inside the ink reservoir 10 and shows the characteristics of the material and thickness of the reinforcing plate 9.

The operation of the inkjet printing head cartridge according to the preferred embodiment of the present invention configured as described above will be described with reference to FIGS. 1 to 3.

First, the working fluid is supplied into the ink reservoir 10 through the ink inlet 4 so as to fill a working fluid such as ink in the cartridge, and the ink inlet 4 after the ink reservoir 10 is filled with ink. ) Is closed with a sealing plug (2). Next, air is drawn out of the space of the ink reservoir 10 in which ink is not filled by using a vacuum pump to generate negative pressure inside the ink reservoir 10.

As the ink is consumed through the discharge passage 5 via the mesh filter 3, the pressure difference between the inside and the outside of the ink reservoir 10 is increased. However, the resilient elastic plate 6 and the reinforcing plate 9 prevent the hasty collapse of the ink reservoir 10 and maintain an optimum negative pressure inside the ink reservoir 10. Thus, the external pressure, ie atmospheric pressure, is balanced by the elastic plate 6 and the reinforcement plate 9.

Therefore, in the process of consuming ink, the end walls of the ink reservoir 10 not reinforced by the elastic plate 6 and the reinforcement plate 9 behave indefinitely by the pressure of the ink and the external atmospheric pressure. On the other hand, the center portion of the portion of the elastic plate 6 attached on the side wall of the ink storage bag 10, which is not reinforced by the reinforcement plate 9, is deformed relatively much compared with both ends reinforced by the reinforcement plate 9. Approach each other.

In particular, when the central portion of the reinforcing plate (9) is formed to protrude in a wave toward the central portion of the elastic plate 6, the elastic plate 6 having an arch shape is the upper and lower portions of the arch It is relatively more deformed than the site and approaches each other.

According to the embodiment of the present invention described above, the uniform and complete flow of ink from the ink reservoir 10 is ensured. In addition, not only can the negative pressure be stably maintained inside the ink storage bag 10, but also the manufacturability in mass production is improved.

 According to the inkjet printing head cartridge according to the present invention, not only can the negative pressure be stably maintained inside the ink reservoir, but also the productivity in mass production is improved.

Although the present invention has been described with reference to the embodiments illustrated in the accompanying drawings, it is merely an example, and those skilled in the art may realize various modifications and equivalent other embodiments therefrom. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is an exploded perspective view showing a cartridge for an inkjet printing head according to an embodiment of the present invention;

FIG. 2 is a side view seen from the “X” direction of FIG. 1;

3 is a cross-sectional view taken along line III-III of FIG. 2;

4 is a reference diagram for explaining a change in curvature of the elastic plate and the reinforcement plate shown in FIGS. 1 to 3.

<Description of Symbols for Major Parts of Drawings>

1 ... base frame 2 ... sealing plug

3.Mesh filter 4 ... Ink inlet

5.Exhaust passage 6 ... Elastic plate

7.Outer body 8 ... Edge flange

9.Reinforcement plate 10 ... Ink reservoir

Claims (8)

Rigid outer body; A rigid base frame fixed to the outer body; An ink reservoir bag formed with holes for supplying and discharging ink, preventing inflow of ink and leakage of ink, and fixed to the base frame; And An arch-shaped elastic plate coupled to an outer wall of the ink storage bag and elastically deformed according to the consumption of ink to maintain a negative pressure inside the ink storage bag; Cartridge for an inkjet printing head, characterized in that it comprises a. The method of claim 1, And a reinforcing plate coupled to a portion of an outer wall of the elastic plate to partially reinforce the elastic plate and having elasticity. The method of claim 2, And the reinforcing plate is attached only on both ends of the elastic plate. The method of claim 3, The center portion of the reinforcing plate is an inkjet printing head cartridge, characterized in that protruding in a wave toward the center portion of the elastic plate. The method according to any one of claims 1 to 4, The elastic plate is an inkjet printing head cartridge, characterized in that formed in a uniform thickness. The method of claim 2, s is a variable defining the position of the elastic plate, Is the radius of curvature of the elastic plate at the position of s, k and n are selected from conditions for providing optimum control characteristics of the pressure operating inside the ink reservoir and are respectively of complete thickness with respect to the elastic plate and the reinforcement plate. Coefficients defining a given contour of change and thickness change, Q is a coefficient that depends on the maximum working pressure inside the ink reservoir and indicates a property that is characteristic of the material and thickness of the reinforcement plate, the elastic plate and the reinforcement plate Is an equation The inkjet printing head cartridge of claim 1, wherein the volume of the ink reservoir bag is changed. The method of claim 1, And the ink reservoir is formed of at least two film layers. The method of claim 5, An inner film layer in contact with ink is metallized, and an outer film layer to which the elastic plate is attached is made of a thermoplastic material.