JPH05185603A - Ink-jet recorder - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide an inkjet recording apparatus capable of realizing stable printing. An inkjet head 200 that ejects ink at a right angle to a carrying direction of a carriage 203, an ink tank 201 that supplies ink to the inkjet head 200, and an ink path between the inkjet head 200 and the ink tank 201 are provided. Pressurizing pump 2 provided with check valves 3 and 4 and a diaphragm 7 as pressure generating means.
In the ink jet recording apparatus 02, both of which are mounted on the carriage 203, a material having elasticity is used for the diaphragm 7, and the opening / closing direction of the check valves 3 and 4 and the direction of the ink path passing through the check valves 3 and 4 are set. Carriage 203
It is characterized in that it is substantially perpendicular to the conveying direction of.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly to a pressure pump.

[0002]

2. Description of the Related Art Conventionally, ink jet printer pumps of this type cannot print due to ink being filled from the ink tank to the head at the start of use of the printer, the head being mixed with air bubbles and foreign matter, and dust being attached to nozzles. It has been aimed at recovery in the case of. Especially for the purpose of recovering the printable state of the head, it is essential for the ink jet printer. For this reason, many general inkjet printers are equipped with a pressurizing pump that pressurizes the ink supply system from the inside and a suction pump that is external to the ink supply system and that sucks the ink from the head nozzle by negative pressure. .. Furthermore, most of these pumps have a variable internal volume of the pump for generating pressure and are equipped with a valve mechanism.

As a conventional ink jet printer pump, there is one disclosed in, for example, Japanese Unexamined Patent Publication No. 2-188261 shown in FIGS. 8, 9, and 10. As shown in FIGS. 8 and 9, the ink is taken in by the small diameter portion 100 having the V-shaped groove 104 and the valve member 101 slidably attached to the small diameter portion 100.
Is guided to the liquid chamber 103 without flowing back. Furthermore, FIG.
As shown in FIG. 0, there is also an example in which the valve plate 105 is used as a member having the same function as the valve member 101 described above.

[0004]

However, in the above-mentioned prior art, since the direction of the ink path between the ink jet head and the ink tank is the same as the carrying direction of the carriage,
An unstable pressure is generated by the inertia of the ink due to the acceleration when the inkjet head is serially conveyed. Therefore, there is a problem that the ink supply pressure to the inkjet head changes, the inkjet head cannot stably eject the ink, and good printing cannot be obtained. When the printing speed is increased, the acceleration is increased and the printing quality is deteriorated. Therefore, in order to stabilize the ink supply pressure, a pressure buffer device (hereinafter referred to as a damper) is installed between the pump and the inkjet head. As a matter of course, the damper is installed on the carriage, and the weight of the damper increases the load on the carriage drive motor, and conversely, there is a problem that the printing speed decreases. When the valve plate is provided, the valve plate opening / closing direction and the carriage transport direction are the same, and therefore the valve plate is opened / closed due to the inertia of the valve plate due to acceleration, resulting in insufficient supply of ink to the inkjet head. However, there is a problem that the printing becomes unstable and finally the printing becomes impossible.

The present invention has been made to solve the above problems, and an object thereof is to provide an ink jet recording apparatus capable of realizing stable printing.

[0006]

In order to achieve the above-mentioned object, an ink jet recording apparatus of the present invention comprises an ink jet head for ejecting ink at a right angle with respect to the carriage carrying direction, and an ink jet for the ink jet head. An ink jet recording apparatus in which a supply ink tank and a pressurizing pump interposed in an ink path between the ink jet head and the ink tank and provided with a check valve and pressure generating means are both mounted on a carriage. It is characterized in that a material having elasticity is used for the pressure generating means. Further, in the pressurizing pump, the opening / closing direction of the check valve is substantially perpendicular to the carriage conveying direction, and the direction of the ink path passing through the check valve is substantially perpendicular to the carriage conveying direction. Is characterized by.

[0007]

According to the above construction of the present invention, since a member having elasticity is used for the pressure generating means of the pressurizing pump and the pump itself has a buffering function, it is not necessary to separately arrange a pressure buffering device. The ink supply system of the inkjet recording device is simplified.

Further, the check valve is arranged at right angles to the moving direction of the carriage to prevent the influence of the acceleration of the carriage on the ink flow.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a perspective view of an ink jet printer equipped with the pressure pump of the present invention. The pump shown in this embodiment is of a pressure type using a diaphragm. Reference numeral 200 denotes an inkjet head, and 201 denotes an ink tank. A pressure pump 202 is arranged below the inkjet head 200 and the ink tank 201 so that they communicate with each other, and each is mounted on a carriage 203. The carriage 203 guides the guide shaft 20 in the recording scanning direction of the recording paper 204.
Guided by 5, it reciprocates in the direction of arrow A. 12, 13
Is a cam having linear cam leads 12a and 13a, which engages with the piston pin 9b of the pressurizing pump 202 as the carriage 203 moves to drive the pressurizing pump 202. 2, 3 and 4 are diagrams showing the configuration of the pressurizing pump of this embodiment. FIG. 2 is a cross-sectional view showing the structure of the pressurizing pump 202 arranged on the carriage 203.
FIG. 3 is an exploded perspective view showing the configuration in FIG. 2 in detail. The configuration of this embodiment will be described with reference to FIGS. 2 and 3.
The ink inlet 1a penetrates from the upper surface of the upper cover 1 to the lower surface with a cylindrical hole having the same diameter. Top cover 1
Is provided with an ink outlet port 1b, from which an ink flow path is constituted by a supply pipe or the like to the head 200. The ink outlet 1b is similar to the ink inlet 1a in the upper cover 1
A hole penetrates from the upper surface to the lower surface, but has a conical shape from the middle to the diameter of the O-ring hole 1c having a diameter substantially the same as the diameter of the O-ring 2.

The pump frame 6 is provided with an O-ring hole 6a communicating with the ink inlet 1a and having the same size as the O-ring hole 1c, and further, the ink inlet 6b is connected by a conical shape. Further, the pump frame 6 is provided with an ink outlet 6c having the same diameter as the ink inlet 1a. The center distance between the ink inlet 1a and the ink outlet 1b of the upper cover 1 and the ink inlet 6b of the pump frame 6
And the center distance of the ink outlet 1c are the same. Further, the two O-ring holes 1c and 6a have the same depth. The ink inflow port 6b and the ink outflow port 6c communicate with each other through a groove 6e, and a spherical ink pressurizing portion 6d is provided in the lower part. During normal printing, the ink tank 2
The ink supplied from 01 enters the pressurizing pump 202 from the ink inflow port 1a, passes through the groove 6e from the check valve 3, passes through the check valve 4, and is supplied from the ink outflow port 1b to the head 200. Since the check valves 3 and 4 can be opened by the pressure generated by the ink flow, they do not hinder the ink flow. Further, from the above description, the opening / closing direction of the check valves 3 and 4 and the direction of the ink path passing through the check valves 3 and 4 are substantially perpendicular to the transport direction of the carriage 203.

At the time of assembly, the O-ring 5 is inserted into the O-ring hole 6a.
Is inserted and the check valve 3 is laminated from above. O-ring hole 1
In c, the O-ring 2 and the check valve 4 are laminated so that the vertical position of the O-ring hole 6a is reversed. O-ring holes 1c and 6
The depth of a is such that the O-rings 2 and 5 are compressed and fully sealed when assembled.

A diaphragm 7 having a spherical surface portion 7a having the same shape as that of the ink pressurizing portion 6d is engaged with the lower portion of the pump frame 6. A protrusion 7b is provided on the spherical surface portion 7a so as to face the ink pressurizing portion 6d. Since the material of the diaphragm 7 has elasticity such as rubber, it can be deformed by a slight internal pressure or external force and can maintain a high sealing property. A lower cover 8 is laminated from below the diaphragm 7. This compresses the side portion 7c of the diaphragm 7 to seal the ink path. Lower cover 8
The piston guide 8a is integrally provided in the. The piston 9 is inserted from below the piston guide 8a, and the hole 7a in the upper portion of the piston 9 is engaged with the projection 7b of the diaphragm 7. Further, the piston 9 is slidable inside the piston guide 8a. Since the piston pin 9b is attached to the piston 9 at a right angle to the moving direction of the carriage 203, the piston guide 8a is provided with a groove 8b for preventing interference with the piston pin 9b.

As described above, the pressurizing pump 202 has a laminated structure, and when assembled, the pump frame 6 and the upper cover 1 are moved upward along the guide pins 14 standing vertically from the lower cover 8. Insert from. Therefore, simple and reliable assembly can be realized. The upper cover 1, the pump frame 6, and the lower cover 8 have screw holes, and the screws 10 are penetrated from the upper cover 1 to the lower cover 8 all at once, and the nuts 11 are tightened to complete the assembly. The two O-rings 2 and 5 and the diaphragm side portion 7c are compressed and tightened with a torque sufficient for sealing.

FIG. 4 is a plan view showing the check valves 3 and 4. The check valves 3 and 4 have a circular portion having a diameter d3, which is concentric with the ring-shaped portion inside the ring-shaped portion having an outer diameter d1 and an inner diameter d2. The material is polytetrafluoroethylene, polyamide, etc., and the thickness is about 0.1 mm. d1 must be slightly smaller than the diameter of the O-ring holes 1c and 6a, and d3 must be smaller than the inner diameter of the O-rings 3 and 4. Since the material itself is flexible, the state shown in the figure is restored even if the outer diameter portion is fixed and the inner diameter portion is displaced by an arbitrary amount. Figure 5
6 and 7 are sectional views showing the pressurizing pump of this embodiment. FIG. 5 shows a state where the pressure pump 202 is filled with ink for discharge for the purging operation. By moving the piston 9 downward by the external force B, the spherical surface portion 7a of the diaphragm 7 is also pulled down,
It will be almost inverted. At this time, since the volume inside the pressurizing pump 202 rapidly increases, the pressure inside the pressurizing pump 202 becomes a negative pressure, and the ink is filled from the ink tank 201 into the space formed by reversing the ink pressurizing portion 6d and the spherical surface portion 7a. It Since the inside of the pressurizing pump 202 has a negative pressure, the check valve 4 is closed, the close contact between the check valve 4 and the pump frame 6 is ensured, and there is no backflow of ink from the head side.
The flow direction of the ink when passing through the check valve 3 and the opening / closing direction of the check valve 3 are substantially the right angle to the carrying direction of the carriage 203, that is, the arrow A direction in FIG. Since the check valve 3 itself is flexible, the opening / closing when ink flows is slight, and the opening / closing direction is always substantially perpendicular to the carriage transport direction. Therefore, the influence of the inertia of the ink due to the acceleration during carriage conveyance on the opening and closing of the check valves 3 and 4 is small.

FIG. 6 shows how the ink filled in the pressure pump 202 is discharged. When the piston 9 is pushed up by the external force D, the pressure pump 20
The ink inside 2 becomes a positive pressure, passes through the check valve 4, and passes through the head 2
It flows to the 00 side. At this time, the check valve 3 is closed, and due to the close contact between the check valve 3 and the upper cover 1, there is no backflow of ink to the ink tank 201 side. The flow direction of the ink when passing through the check valve 4 and the opening / closing direction of the check valve 4 are substantially perpendicular to the carrying direction of the carriage 203, that is, the direction of arrow A in FIG. It becomes the direction of arrow E. The external force B in FIG. 5 and the external force D in FIG.
2 and 13 are generated by the operation of the carriage 203.

FIG. 7 is a side view showing means for operating the piston 9 in the pressurizing pump of this embodiment. When the carriage moves in the direction of arrow F when the purging operation is required, the piston pin 9b moves downward along the cam lead 13a, and the pressure pump 202 is filled with ink. That is, the state shown in FIG. 5 is obtained. Next, when the carriage 203 moves in the direction of arrow G, the piston pin 9b is pushed up,
The ink is pressurized and discharged from the head 200. That is, the state shown in FIG. 6 is obtained.

[0017]

As described above, according to the present invention, since the elastic material is used for the pressure generating means of the pressurizing pump, the fluctuation of the ink supply pressure due to the acceleration during the serial conveyance of the carriage can be suppressed by the elastic pressure. Since there is no need for a pressure stabilizing device such as a damper, the carriage can be reduced in weight because it can be buffered by the generating member, which contributes to an improvement in the printing speed, and stable printing can be performed. Further, in the pressurizing pump, since the opening / closing direction of the check valve is substantially perpendicular to the carriage carrying direction and the direction of the ink path passing through the check valve is substantially perpendicular to the carriage carrying direction, Thus, it is possible to prevent an unprintable state from occurring due to a shortage of supply of the ink.

[Brief description of drawings]

FIG. 1 is a perspective view showing a printer equipped with an inkjet printer pump of the present invention.

FIG. 2 is a sectional view showing an embodiment of the present invention.

FIG. 3 is an exploded perspective view showing a component structure of an embodiment of the present invention.

FIG. 4 is a plan view of one component of one embodiment of the present invention.

FIG. 5 is a sectional view showing the operation of the embodiment of the present invention.

FIG. 6 is a sectional view showing the operation of the embodiment of the present invention.

FIG. 7 is a sectional view showing the operation of the embodiment of the present invention.

FIG. 8 is a sectional view showing the operation of the conventional technique.

FIG. 9 is a sectional view showing a conventional technique.

FIG. 10 is a sectional view showing a conventional technique.

[Explanation of symbols]

 1 Upper cover 2 O-ring 3 Check valve 4 Check valve 5 O-ring 6 Pump frame 7 Diaphragm 8 Lower cover 9 Piston 9b Piston pin 200 Inkjet head 201 Ink tank 202 Pressurizing pump 203 Carriage

Claims (2)

[Claims] 1. An ink jet head for ejecting ink at right angles to a carriage carrying direction, an ink tank for supplying ink to the ink jet head, and an ink path interposed between the ink jet head and the ink tank. An ink jet recording apparatus in which a pressure pump having a stop valve and a pressure generating means is both mounted on a carriage, wherein an elastic material is used for the pressure generating means of the pressure pump. 2. In the pressurizing pump, the opening / closing direction of the check valve is substantially perpendicular to the carrying direction of the carriage,
2. The ink jet recording apparatus according to claim 1, wherein the direction of the ink path passing through the check valve is substantially perpendicular to the carriage transport direction.