JPH0330954A - Ink jet printer - Google Patents

Abstract

PURPOSE:To prevent the clogging of a nozzle due to the drying and solidifica tion of ink at the leading end of the nozzle by sending steam to a cap from a ink tank at the time of capping by allowing the cap and the ink tank to communicate with each other by a pipe. CONSTITUTION:An ink jet head 1 reciprocally moves on guide shafts 3 along a platen 13 and, when the printing of the head 1 is completed, a current is supplied to a solenoid 5 to move a cap 4 in a direction getting away from the guide shafts 3. During this time, the head 1 on a carriage 2 moves to the front surface of the cap 4 and, when the supply of a current to the solenoid 5 is cut off, a capping state is formed. In the capping state, the nozzle opening end 12 containing the orifice of the nozzle 11 of the head 1, the small chamber formed by the cap 4 and the upper part of the ink tank 6 become a communica tion state by a communication tube 9 and the steam in the ink tank 6 is sent in the small chamber of the cap 4. An elastomer such as a seal rubber 10 having ink resistance is bonded to the pressing surface to the head 1 of the cap 4 to keep the airtightness in the cap 4 high.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet printer equipped with a head protection mechanism and an ink supply mechanism, and particularly relates to an inkjet printer having a cap and an ink tank.

[Conventional technology]

2. Description of the Related Art In recent years, with the spread of office automation, there has been an increasing demand for creating and printing documents in the office or at home, and there is a particular need for printers with low noise and good print quality. Inkjet printers are being put into practical use as printers that meet these demands. However, since liquid ink is used, the ink may dry and solidify at the nozzle opening end, causing nozzle clogging.
There is a problem in that the ink in the ink tank evaporates and physical properties such as viscosity change, making it impossible to obtain stable ink droplet ejection properties.

FIG. 4 is a configuration diagram of a head protection mechanism and an ink supply mechanism of an inkjet printer, which is an example of a conventional inkjet printer.

As shown in FIG. 4, in order to solve the above-mentioned problem, the conventional inkjet printer has an inkjet printer mounted on a carriage 2 that moves on a guide shaft 3. The capping structure that seals the nozzle end face 12 of the head 1 into the small chamber of the cap 4 at the provided home position prevents the nozzle opening end 14 from drying out and retains moisture to keep the small chamber of the cap 4 at high humidity. Humidifying tank 1
6 and a humidifying tube 17, and an ink bag 15 made of polyethylene or the like that is closed except for the connection part of the ink supply tube 8.
This prevents the ink 7 from evaporating more than the ink bag. In addition, if the ink bag is a box-shaped ink tank, it should be opened to the atmosphere to prevent negative pressure from being transmitted to head 1 when ink is supplied to head 1, and a solenoid valve should be closed when not printing to prevent evaporation. Alternatively, a one-way valve is used in the ink tank. Note that 5 is a solenoid for driving the cap 4.

[Problem to be solved by the invention]

In the conventional inkjet printers mentioned above, there is a limit to the amount of moisture that can be held in the humidifying tank even if a head protection mechanism, that is, a capping mechanism is used, and the moisture evaporates from the cap that is opened during printing. , it will be necessary to replenish the water or replace the humidifying tank. In other words,
It is necessary to have as much space as possible to secure the capacity of the humidification tank, and the structure must be easy to replace.
Another disadvantage is that running costs increase due to the increase in consumable parts.

In addition, regarding the ink supply mechanism in the inkjet printer mentioned above, when a polyethylene bag is used as an ink tank, negative pressure is transmitted to the head during the shrinking and deforming process of the bag as ink is consumed, resulting in defects such as ink droplet failure. This method has the drawback that it causes problems, and it is also difficult to detect the amount of remaining ink, making it unreliable. On the other hand, when the ink tank is box-shaped, a valve mechanism is required as described above, which is a drawback in that it becomes an obstacle to lowering the price.

The objects of the present invention are to prevent ink from drying out, to provide stable ink supply that prevents the generation of negative pressure during ink supply, to detect the remaining amount of ink with high reliability, to facilitate maintenance, and to reduce the size and cost of the device. An object of the present invention is to provide an inkjet printer that can realize the following.

[Means to solve the problem]

The inkjet printer of the present invention includes an inkjet head mounted on a carriage that moves on a guide shaft, and a cap that forms a small chamber closed with the nozzle opening end of the head during non-printing and is driven by a solenoid. An ink tank that supplies ink to the head via an ink supply tube, and an opening formed in the cap and an opening formed in the upper part of the ink tank and connected to an opening in the upper space of the ink. A head protection mechanism and an ink supply mechanism are formed by these communication tubes.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a head protection mechanism and an ink supply mechanism of an inkjet printer showing one embodiment of the present invention.

As shown in FIG. 1, this embodiment includes an inkjet head 1 mounted on a carriage 2 that moves on a guide shaft 3, and a small chamber that is closed with the nozzle opening end of the head 1 during non-printing and a solenoid. an ink tank 6 that supplies ink 7 to the head 1 through an ink supply tube 8; It has a communication tube 9 connected to an opening opening into the space, and these form a head protection mechanism and an ink supply mechanism.

That is, in this embodiment, the ink tank 6 has no openings other than the ink supply port to the spatula 1 and the connection port to the cap 4, and the cap 4 has no openings other than the ink supply port to the head 1 and the connection port to the cap 4. The cap 4 and the ink tank 6 are connected to each other by a tube 9.

FIG. 2 is an enlarged sectional view of the tip and cap of the head shown in FIG. 1.

As shown in FIG. 2, a plurality of nozzles 11 are formed at the tip of the head 1, and the cap 4 has an open opening connected to the communication tube 9 and a seal rubber lO corresponding to the tip of the spatula 1. is forming.

The nozzle opening surface 12 of the head 1 and the cap 4 form a closed chamber.

FIG. 3 is a schematic diagram of the printing section showing the position of the cap on the inkjet printer in FIG. 1.

As shown in FIG. 3, the inkjet heater 1 is fixed on a carriage 2 that is slidably mounted on a guide shaft 3, and moves parallel to the guide shaft 3.

A printing paper 14 is wound around a platen 13 arranged to face the head 1, and the printing paper 14 is fed as the platen 13 rotates. By ejecting ink from the head 1 in synchronization with the movement of the carriage 2 and the rotation of the platen 3, characters or images are output on the printing paper 14. Further, a cap 4 is provided alongside the platen 13, and the head position opposite to the cap 4 is called a home position, which is the head standby position during non-printing.

Next, the operations of the head protection mechanism and ink supply mechanism in the inkjet printer of this embodiment will be described with reference to FIGS. 1 to 3.

First, the head 1 moves back and forth on the guide shaft 3 along the platen 13, and when the printing of the head 1 is completed, the solenoid 5 is energized and the intervening link mechanism moves the cap 4 in the direction away from the guide shaft 3. .

During this time, the head 1 on the carriage 2 moves to the front of the cap 4, and then the power to the solenoid 5 is cut off, thereby forming the capping state shown in FIGS. 1 and 2.

In such a capping state, the small chamber formed by the nozzle opening end 12 including the nozzle 11 opening of the head 1 and the cap 4 is connected to the upper part of the ink tank 6 through the communication tube 9, so that the vapor in the ink tank 6 is It is sent into the small chamber of cap 4.

In addition, the cap 4 is pressed against the spatula l by adhering an ink-resistant sealing rubber 10 to the surface, such as an elastic material such as fluorocarbon rubber or silicone rubber.
I try to keep the interior airtight.

In addition to the communication port of the tube 9 and the communication port of the ink supply pipe 8 to the head 1, the ink tank 7 has an ink supply port (not shown) that opens only when replenishing ink.

In short, the feature of this embodiment is that a capping mechanism is formed to cover the nozzle opening end at the tip of the head during non-printing, and the ink tank is communicated with the small chamber closed by this capping and facing the nozzle opening end through a pipe or the like. In particular, the connection port on the ink tank side of the tube connecting the cap and the ink tank is provided at a position where it does not directly touch the ink on the top surface of the ink tank. Also,
The ink tank has no openings other than the connection port with the cap and the ink supply port to the head except when replenishing ink, and the cap also has no openings other than the head pressing surface and the connection port with the ink tank. do not have. Therefore, during capping, the ink tank, head, and cap form a completely closed thread, and the nozzle opening end of the head is isolated from the outside air.

〔Effect of the invention〕

As explained above, in the inkjet printer of the present invention, by communicating the cap and the ink tank through a pipe, steam is sent from the ink tank to the cap during capping, so the inside of the cap is kept at high humidity, and the nozzle tip is This has the effect of preventing clogging due to ink drying and solidification, and preventing changes in the physical properties of the ink due to evaporation of the ink in the ink tank.

Also, since the cap is open when printing,
The inside of the connected ink tank is also opened to the atmosphere, so that the pressure is always maintained at 1 atmosphere while ink is being supplied to the head, and a stable ink supply can be realized.

In addition, the amount of ink remaining in the ink tank can be detected by determining the liquid level, so it is possible to use a float or
This has the effect of making it possible to detect the remaining amount with high reliability using various simple means such as using an electrode or a phytosensor.

Furthermore, according to the present invention, the only consumable item is ink, which makes maintenance easier and reduces running costs compared to the case where humidifying liquid or the like is used, and also reduces the number of parts and equipment. This has the effect of realizing miniaturization.

FIG. 2 is a configuration diagram of a head protection mechanism and an ink supply mechanism of the inkjet printer shown in FIG.

1...Inkjet head, 2...
Carriage, 3... Guide shaft, 4...
...Cap, 5...Solenoid, 6...
...Ink tank, 7...Ink, 8...
... Ink liquid tube, 9 ... Communication tube, 10 ... Seal rubber, 11 ... Nozzle nozzle 13 ... Platen, 14 ... Printing paper, 12... Nozzle opening end.

Claims (1)

[Claims] An inkjet head mounted on a carriage that moves on a guide shaft, a cap that forms a closed chamber with the nozzle opening end of the head during non-printing and is driven by a solenoid, and an ink supply tube to the head. an ink tank through which ink is supplied, and a communication tube connected to an opening formed in the cap and an opening formed in an upper part of the ink tank and opening into the upper space of the ink. An inkjet printer characterized in that these constitute a head protection mechanism and an ink supply mechanism.