JPH11157090A - Ink jet printer with backup mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet printer having a backup mechanism for effectively preventing drying of a nozzle surface of a print head at a low cost with small number of components with a simple constitution. SOLUTION: The ink jet printer comprises a print head for injecting an ink from a nozzle portion to print on a recording medium, and a backup unit 10 having a tray container 11, a sponge 12 made of a fibrous or porous material contained in the container and a non-volatile fluid impregnated into the sponge 12. In this case, the nozzle portion of the head can be brought into pressure contact with or separated from the sponge 12. At the time of bringing into pressure contact with the sponge 12, the nozzle portion of the head is surrounded by the non-volatile fluid 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink-jet printer which is a kind of information processing apparatus.
The present invention relates to an ink jet printer having a backup mechanism for protecting a nozzle portion of a print head from drying when the print head is at rest. Ink-jet printers that record by spraying ink particles directly onto a print medium have no significant restrictions on the print medium, are fast, have low noise, and are easy to colorize in printing. There is something, and the price is going down. At the same time, means for ensuring printhead reliability in inkjet printers is becoming increasingly important.

[0002]

2. Description of the Related Art The nozzles of a print head in an ink-jet printer increase the viscosity of the ink when the print head is in a resting state, or the air bubbles in the ink make it difficult for the ink to come out when printing is started. During printing, bubbles may enter the nozzles and print dots may be missing.Therefore, when turning on the power or at other times, the nozzle part on the head surface is covered with a cap to prevent drying of the nozzles. Are known.

FIG. 1 shows a print head backup device (nozzle protection mechanism) of a conventional ink jet printer of this kind. In FIG. 1, 1 is a print head, 2 is a carriage on which the print head is mounted, 3 is a guide shaft for guiding the carriage, 4 is a feed screw for moving the carriage, 5 is a print medium, 6 is a print area, and 7 is a rubber material. And the like.

A print head 1 mounted on a carriage 2
Prints on the print medium 5 by discharging ink (liquid) by a print pulse while moving in the print area 6. The backup device 7 arranged outside the printing area 6 has a function of covering the nozzle portion on the surface of the print head 1 and preventing the nozzle from drying when printing is stopped or when the power is turned off.

That is, when printing is suspended or the power is turned off, the print head 1 is brought to a predetermined rest position (shown by a broken line) outside the range of the printing area 6 by the carriage 2. At this rest position, the cap-shaped backup device 7 moves to the nozzle side of the print head 1 to cover the nozzle portion and prevent the nozzle from drying. Start printing or power on
At times, after the backup device 7 has retreated from the nozzle portion of the print head 1, the print head 1 is brought to a predetermined print start position in the print area 6 by the carriage 2.

[0006] In the above case, there is also proposed a backup device for performing a suction purge to remove ink with increased viscosity or air bubbles while the backup device (ink suction cap) 7 is placed over the nozzles of the print head 1. Have been. In Japanese Patent Application Laid-Open No. 5-84918, dot printing is performed on a medium by ejecting ink from nozzles of a print head, and when a power supply is turned on or when necessary, an opening of a cap is brought into close contact with the nozzle and suction provided on the cap is provided. In an ink jet printer that sucks ink in the nozzle from a mouth, a material that is housed inside the cap, protrudes from the opening by a predetermined dimension, and has elasticity or porosity so that the protruding surface covers at least the nozzle. There is proposed an ink suction cap having a configuration in which a foam formed by the above is provided, and when the opening of the cap is brought into close contact with the nozzle, the foam is compressed by the predetermined dimension.

According to this conventional ink jet printer, when power is supplied to the apparatus, or when ink is to be sucked from the nozzles of the print head when necessary, the cap is advanced and the foam is pressed against the nozzles and compressed. When the openings are brought into close contact with each other, the foam is compressed by a predetermined dimension. When ink is sucked from the suction port, the ink in the nozzle passes through the foam and is sucked. At this time, the internal pressure decreases, and ink that cannot be completely sucked remains.

Therefore, when the cap is retracted and the opening is separated from the nozzle by a gap that can be ventilated, the inside of the cap becomes atmospheric pressure, the foam is loosely compressed while contacting the nozzle, and the residual ink is sucked. Therefore, if the ink is further sucked, the remaining ink can be sucked without dripping.

[0009]

However, in order to increase the speed of the ink jet printing system, many measures are taken to increase the number of nozzles of the print head. Therefore, enlargement of the print head surface is induced, and the backup device is enlarged based on the enlargement. However, since the conventional backup device is made of a rubber material and is pressed against the gap, a gap is generated due to a variation in parts, causing a problem that the nozzle surface of the print head comes into contact with air from the gap and dries. Was.

[0010] In order to avoid such an obstacle, a method of replacing the print head has been frequently adopted. However, the burden on the user is constantly increasing. Means were required. Therefore, the present invention provides a backup system capable of effectively preventing drying of the nozzle surface of a print head even when the number of nozzles of the print head is increased, with a simple configuration, a small number of parts, and low cost. It is an object to provide an inkjet printer having a mechanism.

[0011]

According to the present invention, there is provided a tray container, a sponge made of a fibrous or porous material contained in the tray container, and a sponge impregnated in the sponge. A backup device made of a non-volatile fluid, a print head that ejects ink from a nozzle portion to print on a recording medium, and at least one of the backup device and the print head is movable to the other side, An ink jet printer having a backup mechanism is provided, wherein a nozzle portion of a print head can be pressed against or separated from the sponge, and the nozzle portion is surrounded by a non-volatile fluid at the time of pressing.

According to the present invention, when the printer is stopped for printing or when the power is turned off, one of the backup device and the print head is moved to the other side, and the nozzle portion of the print head is pressed against the sponge to make the nozzle portion non-volatile. Enclosed with fluid to prevent contact with air and prevent drying of the nozzle. Also, when the printer starts printing or when the power is turned on, the backup device and the print head are separated from each other, and the backup device is in an initial state, but the nozzle portion of the print head is shut off from the air, and drying is prevented, Good printing can be performed without excess fluid adhering to the nozzle portion.

In the initial state where the nozzle is separated from the sponge, the upper surface of the sponge is exposed above the liquid surface of the non-volatile fluid, and the nozzle is pressed against the sponge. The upper surface of the sponge is characterized in that it has a compression ratio reaching the lower part of the liquid surface of the nonvolatile fluid. According to this, in the initial state, the non-volatile fluid descends and sinks due to its gravity, and its liquid level is located below the upper surface of the sponge. Thereby, the holding of the non-volatile fluid by the sponge is completed. When the nozzle portion is in pressure contact with the sponge, the nozzle portion is completely surrounded by the non-volatile fluid and completely shut off from the air.

The non-volatile fluid has a viscosity of 1 to 10 centipoise and a surface tension of 70 dyn / cm or more. Since the non-volatile fluid has an appropriate viscosity and surface tension, the ink liquid can be completely retained by the sponge. The non-volatile fluid may be formed of an oily material having a hydrophobic group as a main component that retains an affinity between an OH group (—OH), an amino group (NH ₃ ), and an alkoxyl group (—COOH). Features. Since the non-volatile fluid has incompatibility with the OH group (-OH), the amino group (NH ₃ ), and the alkoxyl group (-COOH), the non-volatile fluid does not mix with the ink or other liquid, The surrounding of the part shall be stable.

[0015]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 2 is a schematic perspective view of an embodiment of an ink jet printer having the backup device of the present invention, and FIG. 3 shows a positional relationship between the backup device and a printing area in the embodiment. 2 and 3, the portions corresponding to those in FIG. 1 are denoted by the same reference numerals. 1 is a print head, 2 is a carriage on which the print head is mounted, 3 is a guide shaft for guiding the carriage, 4
Is a feed screw for moving the carriage, 5 is a printing medium, 6
Is a print area, 7 is a home position, 8 is a platen, 1
0 is a backup device.

As in the conventional apparatus, the print head 1 mounted on the carriage 2 is reciprocated in a print area 6 in a direction perpendicular to the direction of movement of the print medium 5 in a printing state, while being printed by a print pulse. The ink (liquid) is ejected, and printing is performed on the print medium 5. When printing is stopped or the power is turned off, the print head 1 is brought to a predetermined rest position (home position) 7 outside the range of the printing area 6 by the carriage 2.

The backup device 10 according to the present invention comprises:
It is arranged at a position corresponding to a predetermined position (home position) 7 outside the range of the print area 6. The backup device 10 includes, as shown in FIG. 4, a tray container 11, a sponge 12 housed inside the tray container 11,
The non-volatile fluid 13 impregnated in the sponge 12.

The sponge 12 is made of a porous or fibrous material having a relatively high porosity. The non-volatile fluid 13 includes, for example, an OH group (—OH), an amino group (N
H ₃ ), a non-volatile material such as an oily material which is not mixed with the alkoxyl group (—COOH), that is, has a hydrophobic group having incompatibility as a main component, and is 1 to 10 centipoise (for example, 3 Centipoise) and 70
It is preferable to have a surface tension of dyn / cm or more.

Non-volatile fluid 1 impregnated in sponge 12
The amount of 3 is such that the liquid level of the non-volatile fluid 13 does not reach the upper part of the sponge 12 when the print head 1 is in the printing state, that is, when the backup device 10 is in the non-operation state. Since the non-volatile fluid 13 has an incompatibility with OH groups and the like, if the amount is appropriately selected, the non-volatile fluid 13 accumulates in the lower region inside the sponge 12 by the action of the gravity of the non-volatile fluid 13 itself. As shown in FIG. 4, the liquid surface 13a is located below the upper surface 12a of the sponge 12.

FIG. 5 shows the behavior when the print head 1 is at the home position and the interlocking operation of the backup device. (A), the print head 1 moves downward to the backup device 10 side, and the print head 1
FIG. 4 is a cross-sectional view of a state in which it is in pressure contact with. When the print head is in the pause state or when the power of the ink jet printer is turned off, the print head 1 moves to the home position as described above, but immediately after reaching the home position, the print head 1 descends. It moves to the state of (a). In this state, the nozzle surface of the print head 1 is completely shut off from the air, and the nozzle is prevented from drying.

FIG. 2B shows a state in which the print head 1 has escaped upward from the backup device 10 at the start of printing or at the initial stage when the power is turned on. As the print head 1 moves upward, which is a process, the sponge 12
And expands upward. At this time, the sponge 12 absorbs and removes the non-volatile fluid 13 adhering to the nozzle surface of the print head 1, and supports the print head 1 to smoothly print at the start of printing.

If the removal of the non-volatile fluid 13 is incomplete at this time, a rubber plate or an absorbent (not shown) may be disposed around the periphery of the tray container 11 to more completely remove the non-volatile fluid. The fluid 13 can be removed. As described above, in the process of stopping the print head 1, the air that promotes drying of the nozzle portion is completely shut off, and it is possible to avoid the replacement of the print head due to clogging due to nozzle drying. .

At the start of printing or when the power is turned on, after the print head 1 is completely separated from the backup device 10, the print head 1 is moved from the home position by the carriage 2 to a predetermined print start position in the print area 6. Is done. As described above, the embodiments of the present invention have been described in detail with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various forms, modifications, and corrections are made within the spirit and scope of the present invention. It should be noted that the like is possible.

For example, in the above-described embodiment, the configuration is adopted in which the print head 1 moves up and down at the home position. However, a structure in which the backup device 10 side moves up and down may be adopted.

[0025]

As described above, according to the present invention, there is provided a backup device which has a simple structure, is low in cost, and can effectively prevent drying of a nozzle portion of a print head to improve print quality. An ink jet printer is obtained.

[Brief description of the drawings]

FIG. 1 shows a print head backup device (nozzle protection mechanism) of a conventional inkjet printer.

FIG. 2 is a schematic perspective view showing an embodiment of an ink jet printer having the backup device of the present invention.

FIG. 3 shows a positional relationship between a backup device and a print area in the embodiment.

FIG. 4 is a sectional view showing the backup device according to the embodiment;

FIG. 5 is a cross-sectional view showing the behavior when the print head is at the home position and the interlocking of the backup device.
(A) shows a state where the print head is pressed against the backup device, and (b) shows a state where the print head is retracted from the backup device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Print head 2 ... Carriage 3 ... Guide shaft 4 ... Feed screw 5 ... Printing medium 6 ... Printing area 10 ... Backup device 11 ... Tray container 12 ... Sponge 13 ... Non-volatile fluid

Claims (4)

[Claims] 1. A backup device comprising: a tray container; a sponge made of a fibrous or porous material contained in the tray container; a non-volatile fluid impregnated in the sponge; A print head that prints on a recording medium, and at least one of the backup device and the print head can be moved to the other side, and a nozzle portion of the print head can be pressed against or separated from the sponge. An ink jet printer having a backup mechanism, wherein the nozzle portion is sometimes surrounded by a non-volatile fluid. 2. The sponge is in an initial state in which a nozzle portion is separated from the sponge, an upper surface thereof is exposed above a liquid surface of a non-volatile fluid, and the nozzle portion is in pressure contact with the sponge. The ink jet printer according to claim 1, wherein the upper surface of the sponge has a compression ratio reaching a lower portion of the liquid surface of the non-volatile fluid. 3. The ink-jet printer according to claim 1, wherein the non-volatile fluid has a viscosity of 1 to 10 centipoise and a surface tension of 70 dyn / cm or more. 4. The method according to claim 1, wherein the non-volatile fluid is an OH group (—O
H), an amino group (NH ₃ ), an arboxyl group (—COO
2. The ink jet printer according to claim 1, wherein the ink jet printer is made of an oil-based material having a hydrophobic group that maintains incompatibility with H) as a main component.