JPH1170667A - Ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve the stable supply of an ink to a pressure generating room at the time of high speed printing by providing a buffer tank on a head holder for fixing a recording head unit on a carriage so as to form an ink channel in the head holder, communicating with the buffer tank to the recording head unit. SOLUTION: A recording head comprises a head holder 11 for fixing a recording head unit 10 on a carriage, and a buffer tank 12. The buffer tank 12 is fixed on a step part 24 on the side of the head holder 11 so as to be connected with a channel 25 communicating from the step part 24 to the reserver of the recording head unit 10. As a result, even when a large amount of an ink is consumed in the recording head unit 10, since the ink in the buffer tank 12 immediately above flows into the reserver via the short channel, the ink can be supplied without delay. Moreover, for example, when character data switched to graphic data, a large amount of the ink can be supplied immediately via the channel 25 so as to prevent the water hammer action.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head and a buffer tank mounted on a carriage which moves in the width direction of a recording sheet. The present invention relates to an ink jet recording apparatus that supplies ink to a recording head.

[0002]

2. Description of the Related Art In order to improve print quality in color printing, an ink jet recording apparatus using at least six colors of ink of dark magenta, light magenta, dark cyan, light cyan, yellow, and black has been proposed. .

[0003] In the case of using a multi-color ink as described above, since an ink cartridge for at least six colors is required, the total weight of the carriage becomes large in a recording apparatus in which an ink tank is mounted on the carriage. Therefore, not only is a large output required for the carriage drive motor, but also there are problems such as a large recoil of the carriage upon carriage return.

In order to solve such a problem, as shown in FIG. 9, a buffer tank A as a pressure damper made of a flexible bag is mounted on a carriage, while an ink cartridge B is mounted on a box. A separate ink supply method has been proposed in which ink is pumped into a buffer tank A and ink is supplied to a recording head C via the buffer tank A.

[0005]

According to this, not only can the ink be reliably supplied to the recording head C, but also the overall weight of the carriage can be reduced to achieve high-speed printing and an extended period of ink replenishment. However, since the ink is supplied from the buffer tank A to the recording head C via the ink supply path D such as a tube, the flow path resistance between the buffer tank A and the recording head C increases. In addition, there is a problem that high-speed printing or the like that requires supply of ink at a large flow rate is disadvantageous. The present invention has been made in view of such a problem, and an object of the present invention is to provide an ink jet recording apparatus capable of performing stable printing by stably supplying ink to a pressure generating chamber even during high-speed printing. It is to provide.

[0006]

In order to solve such a problem, according to the present invention, ink of an ink cartridge is supplied to a buffer tank, a part of which is sealed with an elastic film, via an ink supply tube. In an ink jet recording apparatus for performing printing by supplying ink from the buffer tank to a recording head unit, a buffer tank is formed in a head holder for fixing the recording head unit to a carriage, and the recording is performed from the buffer tank to the head holder. An ink flow path communicating with the head unit is formed.

[0007]

The ink is supplied to the recording head unit from a buffer tank provided integrally with the head holder, and the ink flowing backward from the pressure generating chamber of the recording head unit is stored in the buffer tank and the pressure of the adjacent pressure generating chamber is increased. Prevent fluctuations.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a first embodiment of the present invention. FIG. 1 shows an embodiment of the ink jet recording apparatus of the present invention,
The carriage 1 is connected to a motor 3 by a timing belt 2, is configured to be guided by a guide member 4, and moves parallel to a platen 5, and has a recording head 6 mounted thereon.

An ink cartridge 7 is provided on one side of the frame.
And a capping device 9 that is connected to the recording head 6 by an ink supply tube 8 and seals a nozzle plate of the recording head 6 in a non-printing area of a moving path of the recording head 6.

FIG. 2 shows an embodiment of the recording head 1 described above. The recording head 6 includes a recording head unit 10, a head holder 11 for fixing the recording head unit 10 to the carriage 1, a buffer, And a tank 12.

As shown in FIGS. 3 and 4, the recording head unit 10 includes a reservoir 13, an ink supply port 14, a flow path forming substrate 16 for forming a pressure generating chamber 15, and a pressure generating chamber 1.
5, a nozzle opening 17 communicating with
And a resilient plate 20 for sealing the other surface of the flow path forming substrate 16 and receiving the displacement of the piezoelectric vibrator 19.
Is fixed to the lower surface of the head holder 11 with a reservoir 13 communicating therewith.

The buffer tank 12 has a through hole 21 communicating with the reservoir 13 of the recording head unit 10 at a lower portion, and a concave portion 22 opening on a side surface exposed on the surface. A step 23 formed on the side surface of the head holder 11 is formed by sealing with a film 23, and is connected to a flow path 25 communicating from this step 24 to almost the entire region of the reservoir 13 of the recording head unit 10. Is fixed.

The buffer tank 12 has a tube connection port 26 connected to the ink supply tube 8 on the side surface, and receives ink supply from the ink cartridge 7 through a communication hole 28 having an outlet 27 in the recess 22. .

In this embodiment, when printing is performed by supplying a print signal to the recording head unit 10, the pressure generating chamber 15 is pressurized by the displacement of the piezoelectric vibrator 19, and a part of the ink in the pressure generating chamber 15 is removed. The ink is ejected from the nozzle opening 17 as ink droplets, and a part thereof flows backward from the ink supply port 14 to the reservoir 13, and the pressure of the reservoir 13 increases. This increased pressure is applied to the film 2 in the buffer tank 12 immediately above.
3 is deformed and absorbed, thereby preventing the pressure in the other pressure generating chambers 15 from rising.

Even if a large amount of ink is consumed in the recording head unit 10 by this printing, the ink in the buffer tank 12 immediately above flows into the reservoir 13 via a short flow path, so that there is no time delay. Is supplied to the pressure generating chamber 15. Further, even if the ink in the buffer tank 12 becomes wavy due to the movement of the carriage and the pressure fluctuates, the film 23 deforms and absorbs the fluctuation.

Also, even when the data is switched from character data to data that consumes a large amount of ink, such as graphic data, a large amount of ink is supplied from the buffer tank 12 through the flow path 25 having a large opening. ,
The occurrence of the water hammer action is prevented, and the concentration change can be prevented.

In the above-described embodiment, the buffer tank 12 is formed separately and attached to the head holder 11, but as shown in FIG.
A similar effect can be obtained by forming a concave portion 30 having an opening on one side surface and a through hole 31 communicating with the reservoir from the concave portion 30 and sealing the opening of the concave portion 30 with an air-shielding film 32.

FIG. 6 shows another embodiment of the present invention, in which a filter chamber 33 is formed in a region between the tube connection port 26 and the outlet port 27 of the head holder 11, and the tube connection port 26 is formed. Filter 34 so as to separate the
Is provided.

According to this embodiment, the filter 34 can be provided by utilizing the dead space of the head holder 11, and it is possible to eliminate bubbles and foreign matters contained in ink without increasing the size of the recording head. A high recording head can be configured.

In this embodiment, the filter chamber 3
3, the filter is arranged, but the buffer tank 12 and the head holder 1 are arranged as shown in FIG.
By disposing the filter 35 in the connection region with the one opening 25, the filter 35 can be disposed without requiring a significant change in the structure.

FIG. 8 shows another embodiment of the present invention. In this embodiment, the concave portion 22 is provided with the partition member 3.
6, the first and second chambers 22a and 22b connected through a vertical communication channel 37 on one end side.
The first chamber 22a located at the upper part has an ink inlet 27 communicating with the lower end thereof, and the second chamber 22b located at the lower part has the upper surface with the communication channel 37 side facing upward. A slope 22c is formed.

The upper end 37a of the communication channel 37 is positioned so as to be 1/4 to 3/4 of the height h of the first chamber 22a. It is configured to ensure.

According to this embodiment, the bubble E flowing into the second chamber 22b near the through hole 21 for discharging ink to the recording head is communicated along the slope 22c as shown in FIG. Since the air flows backward from 37 to the first room 22a and is trapped in the space F above the first room 22a, it is possible to reliably prevent air bubbles from entering the recording head.

In the above-described embodiment, the recording head unit for pressurizing the pressure generating chamber against the piezoelectric vibrator has been described as an example. However, recording of the type in which the pressure generating chamber is heated and pressurized by vaporization of ink. It is clear that a similar effect can be obtained by using a head unit.

[0025]

As described above, according to the present invention, the ink of the ink cartridge is supplied to the buffer tank, a part of which is sealed with an elastic film, via the ink supply tube, and the recording head unit is supplied from the buffer tank. In an ink jet recording apparatus that performs printing by supplying ink to a recording medium, a buffer tank is formed in a head holder that fixes a recording head unit to a carriage, and an ink flow path that communicates from the buffer tank to the recording head unit is formed in the head holder. Therefore, the ink supply path between the buffer tank and the recording head unit can be shortened as much as possible, so that the flow path resistance is reduced and the compliance of the buffer tank is absorbed by the pressure rise due to the backflow from the pressure generating chamber. Can be used effectively.

Further, the reservoir of the recording head unit can be reduced to such an extent that the reservoir can be connected to the buffer tank. When the flow path forming substrate is made of an expensive silicon single crystal substrate, the cost is reduced by reducing the size of the substrate. It can be reduced.

Further, the volume of the head holder can be effectively used, and the carriage can be reduced in size.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of an ink jet recording apparatus of the present invention.

FIG. 2 is a diagram showing an embodiment of an ink jet recording head suitable for the above-described apparatus, in which one buffer tank is moved upward.

FIG. 3 is a front view showing an embodiment of an ink jet recording head suitable for the above apparatus.

FIG. 4 is a diagram showing an ink jet recording head suitable for the above-described apparatus, in a cross-sectional structure in a direction in which pressure generating chambers are arranged.

FIG. 5 is a view showing another embodiment of the ink jet recording head suitable for the above apparatus.

FIG. 6 is a view showing another embodiment of the ink jet recording head suitable for the above apparatus.

FIG. 7 is a view showing another embodiment of an ink jet recording head suitable for the above apparatus.

FIGS. 8A and 8B are a front view showing another embodiment of a buffer tank mounted on an ink jet recording head suitable for the above apparatus, and a cross-sectional structure taken along line AA. (C) is a diagram showing the state of bubble elimination.

FIG. 9 is a diagram illustrating an ink supply path of an ink jet recording apparatus having a buffer tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Carriage 8, 9 Buffer tank 10-13 Ink cartridge 14-17 Ink supply tube 10 Recording head unit 11 Head holder 12 Buffer tank 13 Reservoir 14 Ink supply port 15 Pressure generating chamber 16 Flow path forming substrate 19 Piezoelectric vibrator 20 Elastic plate DESCRIPTION OF SYMBOLS 21 Through-hole 22 Depression 23 Film 24 Step 25 Connection flow path

Claims (11)

[Claims] An ink jet printer for supplying ink from an ink cartridge to a buffer tank partially sealed with an elastic film via an ink supply tube, and supplying ink from the buffer tank to a recording head unit for printing. An ink jet recording apparatus, comprising: a buffer tank in a head holder for fixing the recording head unit to a carriage; and an ink flow path communicating from the buffer tank to the recording head unit in the head holder. 2. The ink jet recording apparatus according to claim 1, wherein the ink flow path has a width substantially corresponding to a size of the recording head unit in a direction in which the pressure generating chambers are arranged. 3. The ink jet recording apparatus according to claim 1, wherein the buffer tank is located immediately above a reservoir of the recording head unit. 4. The ink jet recording apparatus according to claim 1, wherein said buffer tank is formed as a separate body. 5. The ink jet recording apparatus according to claim 1, wherein the buffer tank is formed by forming a recess in the head holder. 6. The ink jet recording apparatus according to claim 1, wherein the elastic film is located on a front side of the head holder. 7. The ink jet recording apparatus according to claim 1, wherein a filter chamber for containing a filter and communicating with the buffer tank is formed in the head holder. 8. The ink jet recording apparatus according to claim 1, wherein a filter is interposed between the ink flow path and the recording head unit. 9. The ink jet recording apparatus according to claim 1, wherein the buffer tank is positioned in a vertical relationship by a partition member, and is separated into first and second chambers connected by a vertical communication flow path. . 10. An ink inlet communicating with a lower end of the first chamber located at an upper portion, wherein an upper end of the communication flow path has a height of １ ／ to ／ of a height of the first chamber. The ink jet recording apparatus according to claim 9, which is located in the area. 11. The ink jet recording apparatus according to claim 9, wherein the second room located at the lower portion has a slope with the communication hole side facing upward.