JPH0679881A - Ink-jet recording device - Google Patents

Abstract

PURPOSE:To realize an ink-jet recording device, which enables normal recording and in which the efficiency of usage of ink is improved, at low cost. CONSTITUTION:A valve means 12 is closed previously by a controller, a recovery pump 9 for a recovery means 8 connected to an ink vessel 3 through an opening 6 and a connecting means 11 is operated and the inside of the ink vessel 3 is brought to negative pressure, and the valve means 12 is opened and closed so that a pressure value detected by a negative-pressure detecting means 13 is kept within the range of an upper limit value and a lower limit value set when a negative pressure value in the ink vessel 3 is lowered by starting the recording of a recording head 1, and air is flowed into the ink vessel 3.

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 an ink jet recording head for ejecting ink to record on a recording material by using an energy converter, an ink container for storing the ink, and the ink. The present invention relates to an inkjet recording apparatus including a supply unit that connects a container and an inkjet recording head to supply ink to the inkjet recording head.

[0002]

2. Description of the Related Art Conventionally, in this type of ink jet recording apparatus, in order to maintain the performance of the ink jet recording head and prevent ink leakage from the ejection port of the recording head, the ink liquid level of the ink container is arranged at a position lower than the ejection port. By doing so, the ink supply pressure applied to the inkjet recording head is maintained at a negative pressure of a predetermined value. But with this method,
Since there is a restriction on the arrangement position of the ink container with respect to the inkjet recording head, it is difficult in space to arrange the ink container on the carriage in the serial scan type recording apparatus.

As a means for solving the above restrictions, it has been proposed to provide a means for generating a negative pressure in the ink container itself, and the following (a), (b), (c), etc. are known. There is.

(A) An opening of an ink container is covered with a flexible member 200 as shown in FIG. 4, and the flexible member 200 is elastically deformed in response to a negative pressure in the container (Japanese Patent Laid-Open No. Hei 3). -24900).

(B) As shown in FIG. 5, in the ink container body 201, a movable wall that moves toward the ejection port 203 according to the amount of ink ejected from the ejection port 203 is provided.
The negative pressure of the ink in the ink container body 201 is controlled by the frictional force at the contact interface between the movable wall and the inner surface of the ink container body 201. A movable wall 204 provided with an O-ring 202 around the periphery as shown in FIG. 4 and a movable wall 304 made of a diaphragm-like elastic material as shown in FIG.
4355).

(C) As shown in FIG. 6, ink is held in a porous body 400 such as a sponge in the ink container body 401, and a negative pressure is generated by utilizing the capillary force of the porous body.

However, these conventional examples have the following problems. That is, in the conventional technique (a), since the opening of the container that stores the ink is elastically deformed and crushed, the flexible member 200 is largely deformed when the ink is consumed to some extent. Becomes
The distortion increases. Then, further deformation is hard to occur, the negative pressure generated in the flexible member 200 suddenly increases, and the ink is not supplied. Further, since the flexible member 200 is deformed from the side surface portion, the flexible member cannot be deformed at the opening of the container in which the flexible member 200 is attached, so that ink can be supplied. It has the drawback of disappearing.

According to the experiment, the ink use efficiency in the configuration (a) is only about 50% at maximum, and the ink use efficiency is low. In addition, in the case of the configuration (a) in which the structure can be separated from the ink ejection portion, the flexible member may be restored and air may be sucked into the flexible member 200. When the air is sucked in this way, the ink may not be ejected normally again, and there is a risk that ink may run out.

By the way, in Japanese Utility Model Application Laid-Open No. 61-93246, as a means for improving the use efficiency of ink, the thickness t ₁ and t ₂ of the flexible member 200 are made different from each other so that the thickness t ₂ side is smaller. There is a configuration that can be actively collapsed. However, even in this case, the use efficiency of the ink does not improve to a satisfactory level.

Regarding the prior art (b), in order to maintain the airtightness of the movable wall 204 and the ink container main body 201 and prevent the movable wall 204 from collapsing, the rigidity of the O-ring 202 and the diaphragm is set to be large, It is necessary to increase the thickness of the O-ring 202 and the diaphragm to increase the contact area with the ink container. As a result, the movable wall 204
The frictional force at the contact interface between the ink and the inner surface of the ink container body 201 becomes large, and the starting pressure of the movable wall 204, that is, the differential pressure required to start the movement of the movable wall 204 from the stationary state becomes large. There is a drawback that it is difficult to set the necessary conditions for adjusting the ink negative pressure with high accuracy.

Further, in the prior art (C), since a negative pressure is generated by the capillary force, the high density porous body 400 is used.
Therefore, the amount of ink that can be filled with respect to the volume of the ink container is reduced. Also, the control of the ink supply pressure will not work well, and it will not be possible to use the ink while leaving the ink in the ink container. Therefore, the amount of ink that can actually be used is less efficient than the ink container, and since the porous body 400 is discarded together with the ink container after use, it may have an adverse effect on the environment, or may be recovered / regenerated. Has the disadvantage that it costs a lot of money.

In view of the above problems of the prior art, an object of the present invention is to provide an ink container so that normal recording can be performed when a positive pressure due to a head difference is applied to a recording head mounted on a carriage. An ink jet recording device that can maintain a predetermined negative pressure value and can be applied to a serial scan type, has a simple ink container structure, has good ink use efficiency, and is advantageous in terms of cost and environment. Is to provide.

[0013]

An ink jet recording apparatus according to the present invention includes an air suction means for sucking air in an ink container, and the air suction means to control the pressure in the ink container to a predetermined negative pressure value. Pressure control means for maintaining

In the ink jet recording apparatus of the present invention, a recovery pump for sucking air from the ejection port of the ink jet recording head to recover the deteriorated function of the ink jet recording head may be shared as the air suction means.

Further, in the ink jet recording apparatus of the present invention, the pressure control means detects the pressure inside the ink container, the negative pressure detection means, the fluid resistor, and the air in the ink container through the fluid resistor. Valve means for flowing into
When the air suction unit is operated to suck the air in the ink container and the pressure in the ink container detected by the negative pressure detection unit becomes zero negative pressure, after stopping the air suction unit, When the negative pressure value detected by the negative pressure detection means reaches a predetermined upper limit value as the recording progresses, the valve means is opened to allow air to flow into the ink container, and the negative pressure detection means When the detected negative pressure value reaches a predetermined lower limit value, the valve means is closed to maintain the pressure in the ink container within the predetermined negative pressure value.

In the ink jet recording apparatus of the present invention, the air suction means may be constantly connected to the ink container mounted in the carriage and the pressure control means arranged outside the carriage.

Further, in the ink jet recording apparatus of the present invention, the ink container and the pressure control means connected to the ink container are mounted in the carriage, and when the air suction means tries to suck the air in the ink container. , A unit that abuts the opening of the pressure control unit by the movement of the carriage to suck the air in the ink container.

[0018]

Since the air in the ink container is sucked by the air sucking means to maintain the pressure in the ink container at a predetermined negative pressure value, normal recording can be performed with the ink container having a simple structure. Thus, an ink jet recording apparatus can be realized which has good ink usage efficiency and is advantageous in terms of cost and environment.

When the recovery pump is also used as the air suction means, it can be manufactured at a lower cost.

When the air suction means moves the carriage during suction and comes into contact with the opening of the pressure control means, it is possible to eliminate the circulation of the connecting means for circulating the air.

[0021]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a vertical sectional view of a first embodiment of an ink jet recording apparatus of the present invention.

This ink jet recording apparatus comprises a recording head 1, a supply means 2, an ink container 3, a carriage 7, a connecting means 11, a valve means 12, a negative pressure detecting means 13 and a fluid resistor 1.
4, a recovery unit 8 and a control unit (not shown).

The recording head 1 is mounted on a carriage 7,
It has an energy converter for ejecting ink, and an ejection port is provided in the downward direction, and the ejection port is arranged under a positive pressure due to the head difference h of the ink container 3. The supply unit 2 connects the recording head 1 and the ink container 3 and supplies the ink in the ink container 3 to the recording head 1. The ink container 3 is provided with a flexible member 5 formed of a bag or thin rubber inside the ink container body 4. The ink is stored inside the flexible member 5 and is liquid-tightly connected to the supply means 2 by a joining member such as a rubber stopper. Further, the opening 6 provided in the ink container body 4 has a sealing member 10 provided in the carriage 7.
Are airtightly connected, and are connected to the negative pressure detecting means 13 and the valve means 12 by the connecting means 11. Fluid resistor 1
Reference numeral 4 is provided on the atmosphere communication side of the valve means 12 and adjusts the inflow speed of the air flowing in when the valve means 12 is open.
The recovery means 8 has a recovery pump 9 connected to the cap 15, and the cap 15 is closely attached to the ejection port of the recording head 1 to operate the recovery pump 9 and is used for recovery of the recording head 1 such as clogging. The recovery pump 9 is further connected to a negative pressure detecting means 13 and a valve means 12 via a connecting means 11.

The negative pressure detecting means 13 detects the air pressure in the ink container 3 and is electrically connected to a controller (not shown) together with the valve means 12 and the recovery pump 9.

In the time chart of FIG. 2, (a) shows the change in the pressure applied to the recording head 1 depending on the recording time, and (b) shows the on / off state of the recovery pump 9. Further, (c) represents opening and closing of the valve means 12.

When the new ink container 3 is replaced at the recording time T ₁ , the controller does not have a negative pressure generating means in the ink container 3 itself, so that the controller initially becomes a positive pressure state corresponding to the head pressure difference h. Therefore, the valve means 12 is closed to seal the ink container 3. Next, the recovery pump 9 is operated by the signal indicating that there is an ink container output from the ink container replacement detection means (not shown) to suck the air in the ink container 3 and the pressure inside the ink container 3 decreases. When the negative pressure detecting means 13 receives a signal notifying that the detected value has become zero negative pressure, the operation of the recovery pump 9 is stopped.
The recording by the recording head 1 is started from this state (the state where the recording time is 0), the negative pressure value is increased by the air expansion of the ink consumption due to the recording, and the value detected by the negative pressure detecting means 13 is the negative pressure value P. _When it reaches _max , the valve means 12 is opened, and air flows into the ink container 3 through the fluid resistor 14 to reduce the negative pressure value, and the value detected by the negative pressure detecting means 13 reaches P _min . Sometimes the valve means 12 is closed.
By the control as described above, the negative pressure value applied to the recording head 1 can be maintained within a certain range. Here, the negative pressure value P
_The values of _max · P _min are values that do not hinder the recording of the recording head 1, and the negative pressure detection means 13 is set to that value.

A pressure sensor using a diaphragm is suitable for the negative pressure detecting means 13, and its position is shown in FIG.
There is no functional problem even in the middle of the supply means 2 other than the position. As the fluid resistor 14, a filter made of resin, paper, ceramic, fiber or the like having fine pores is suitable. The connecting means 11 is preferably one having good flexibility and good gas barrier properties, and a tube made of an ethylene / vinyl alcohol copolymer resin, an aluminum vapor deposition polyethylene tube, or the like is suitable as a material. In addition, ordinary polyethylene or vinyl chloride alone can be used by using the following method even if it has a poor gas barrier property. That is, in order to prevent the leakage of ink from the ejection port due to the shift from negative pressure to positive pressure due to gas permeation that occurs during long-term storage, the cap 15 is pressed against the recording head 1 for sealing. Then, at the start of printing, the pressure inside the ink container 3 is detected by the negative pressure detection means 13, and when it is P _min (or 0) or less, normal printing can be performed by performing the sequence at the time of ink container replacement. it can.

The ink container body 4 also preferably has a good gas barrier property, and the same material as that of the connecting means 11 is suitable. Further, the evaporation of ink can be reduced by laminating polyethylene / polypropylene having a water vapor barrier property.

The flexible member 5 has gas / water vapor barrier properties and is required to have ink resistance. As the material,
From the ink side, a three-layer structure of polyethylene / vinylidene chloride / nylon or a two-layer structure of polypropylene / polyethylene terephthalate is suitable.

Further, the recording head 1 is an inkjet recording head for recording by forming flying droplets by utilizing thermal energy among the inkjet recording methods, and its typical configuration and principle are as follows. For example, it is preferable to use the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796. This method is applicable to both so-called on-demand type and continuous type, but in particular,
In the case of the on-demand type, the electrothermal converter arranged corresponding to the sheet or liquid path where the liquid (ink) is held corresponds to the recorded information and the temperature rises rapidly beyond the nucleate boiling. By applying at least one drive signal to generate heat energy in the electrothermal converter, causing film boiling on the heat-acting surface of the recording head, resulting in a one-to-one correspondence with this drive signal. This is effective because bubbles can be formed in the liquid (ink). The growth of this bubble,
The contraction causes the liquid (ink) to be ejected through the ejection opening to form at least one droplet. It is more preferable to make the driving signal into a pulse shape because bubbles can be grown and contracted immediately and appropriately, and thus a liquid (ink) with excellent responsiveness can be ejected.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise of the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head 1, a combination constitution of a discharge port, a liquid passage, and an electrothermal converter as disclosed in the above-mentioned respective specifications (straight liquid passage or right-angled liquid passage).
In addition, a configuration using US Pat. No. 4,558,333 or US Pat. No. 4,459,600, which discloses a configuration in which a heat acting surface is arranged in a bending region, is also included.

In addition, JP-A-59-123670, which discloses a structure in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and a pressure wave of thermal energy is absorbed. It is also effective in the configuration based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration in which the opening corresponds to the ejection portion.

Further, as a full line type recording head having a length corresponding to the width of the maximum recording medium which can be recorded by the recording apparatus, the length can be increased by combining a plurality of recording heads as disclosed in the above-mentioned specification. Either of the structure satisfying the requirement or the structure as one recording head integrally formed may be used.

Further, it is preferable to add recovery means, preliminary auxiliary means, etc. to the recording head because the effect can be further stabilized. Specific examples thereof include capping means, cleaning means, pressurizing or suctioning means for the recording head, preheating means using an electrothermal converter or another heating element or a combination thereof, and recording. It is also effective to perform a stable recording by performing a preliminary discharge mode in which another discharge is performed.

Further, as the recording mode of the recording apparatus, not only the mainstream color such as black is recorded but also the recording head may be integrally formed or a plurality of them may be combined. Alternatively, the apparatus may be provided with at least one of full colors by color mixing.

Although the ink used in the recording head 1 is a liquid, it is an ink that solidifies at room temperature or below and that softens at room temperature or is a liquid, or the ink itself in the ink jet system described above. Generally, the temperature is controlled in the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature of the ink so that the viscosity of the ink is in a stable ejection range. Good.

In addition, the temperature rise due to the thermal energy is positively prevented by using it as the energy for changing the state of the ink from the solid state to the liquid state, or the ink is solidified in a standing state for the purpose of preventing evaporation of the ink. In some cases, such as ink that is liquefied by applying heat energy according to a recording signal and ejected as a liquid ink, or one that has already started to solidify when it reaches a recording medium. It is also possible to use an ink that has the property of being liquefied only by heat energy. In such a case, the ink is as described in JP-A-54-56847 or JP-A-60-71260.
It may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the concave portion or the through hole of the porous sheet. The most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In the ink jet recording apparatus of this embodiment, the recording head is mounted on the carriage and is of the serial scan type. However, since the inside of the ink container is maintained at a predetermined negative pressure value, the structure of the ink container is simple. Despite this, normal recording is possible, ink usage efficiency is good, the cost is low, and the environmental impact is good.

FIG. 3 shows a vertical sectional view of a second embodiment of the ink jet recording apparatus of the present invention.

In this ink jet recording apparatus, the line shown in FIG.
Connection means 11, valve means 12 and
And the negative pressure detecting means 13 instead of the connecting means 11 respectively.₁ ,
Valve means 12₁ , And negative pressure detection means 13₁ Are all
Carriage 7₁ Disposed inside the valve means 12₁ Is hole 1
6 and the fluid resistor 14₁ Through the sky
Open and close the passage of qi. Also, a recovery means instead of the recovery means 8
8₁ Is the carriage 7 ₁ Press around the aperture 16 of
Cap 15₁ Only rotary pump 9₁ Connected to
There is.

[0043] In this inkjet recording apparatus, a controller (not shown) at the time of replacement of the ink container 3, opening 16 the carriage ₇₁ is moved to a position that meets the cap 15 ₁ recovery means 8 _1, cap 15 ₁ After pressed against the periphery of the aperture 16, to operate the rotary pump 9 ₁ by sucking air in the ink container 3 by a negative pressure in, it causes the operation shown in the time chart of subsequent Figure 2.

In the ink jet recording apparatus of this embodiment, the inside of the ink container is maintained at a predetermined negative pressure value during recording.
It has the same effect as that of the embodiment, but since the connecting means as shown in FIG. 1 does not move around, the periphery of the carriage is neat, and the connecting means is shortened so that the gas blocking property is improved. There is.

[0045]

As described above, according to the present invention, in the ink jet recording apparatus for supplying the ink from the ink container to the ink jet recording head by the supplying means, the pressure controlling means controls the sucking means for sucking the air in the ink container. As a result, the pressure inside the ink container is maintained at a predetermined negative pressure value even in the case where the structure is mounted on the carriage and a positive pressure is applied to the recording head due to the water head difference, so that the structure of the ink container is kept normal without complicating. There is an effect that it can be realized even if the ink jet recording apparatus which is capable of recording, has high efficiency of use of ink, is low in cost and is also advantageous in terms of environment is a serial scan type.

Further, the recovery pump for recovering the function of the ink jet connected to the ejection port is also used as the suction means, so that the pressure in the ink container can be maintained at a negative pressure value more easily and inexpensively. The effect is that the device is realized.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment of an inkjet recording apparatus of the present invention.

FIG. 2A is a time chart showing the pressure applied to the recording head 1 of FIG. (B) is a time chart showing ON / OFF of the recovery pump 52 of FIG. 1.
(C) is a time chart showing opening and closing of the valve means 12 of FIG.

FIG. 3 is a vertical cross-sectional view of a second embodiment of the inkjet recording apparatus of the present invention.

FIG. 4 is a partial cross-sectional side view of a first conventional example in an ink container.

FIG. 5A is a longitudinal sectional view of a second conventional example of an ink container,
(B) is a longitudinal sectional view of a third conventional example of the ink container.

FIG. 6 is a vertical cross-sectional view of a fourth conventional example of an ink container.

[Explanation of symbols]

 1 Recording Head 2 Supplying Means 3 Ink Container 4 Ink Container Main Body 5 Flexible Member 6 Opening 7 Carriage 8 Recovery Means 9 Recovery Pump 10 Sealing Member 11 Connecting Means 12 Valve Means 13 Negative Pressure Detecting Means 14 Fluid Resistor 15 Caps h Head pressure difference

Front Page Continuation (72) Inventor Nori Hattori 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (5)

[Claims] 1. An ink jet recording head for performing recording on a recording material by ejecting ink using an energy converter, an ink container for storing the ink, and the ink container and the ink jet recording head are connected to each other. In an inkjet recording apparatus including a supply unit that supplies ink to an inkjet recording head, an air suction unit that sucks air in the ink container, and a pressure in the ink container that is a predetermined negative pressure by controlling the air suction unit. An ink jet recording apparatus comprising: a pressure control unit for maintaining a value. 2. The ink jet recording apparatus according to claim 1, wherein a recovery pump for sucking air from an ejection port of the ink jet recording head to recover the deteriorated function of the ink jet recording head is also used as the air suction means. 3. A pressure control means, a negative pressure detection means for detecting the pressure in the ink container, a fluid resistor, and a valve means for allowing air to flow into the ink container via the fluid resistor. The air suction means is operated to suck the air in the ink container, and when the negative pressure in the ink container detected by the negative pressure detection means becomes zero, the air suction means is stopped. When the negative pressure value detected by the negative pressure detection means reaches a predetermined upper limit value as the recording progresses, the valve means is opened to allow air to flow into the ink container, and the negative pressure detection means 3. The control unit configured to close the valve means to maintain the pressure in the ink container within a predetermined negative pressure value when the negative pressure value detected by the sensor reaches a predetermined lower limit value. The inkjet recording device described. 4. The ink jet recording apparatus according to claim 1, wherein an air suction means is always connected to an ink container mounted in the carriage and a pressure control means arranged outside the carriage. . 5. An ink container and a pressure control unit connected to the ink container are mounted in a carriage, and when the air suction unit tries to suck the air in the ink container, the pressure is generated by the movement of the carriage. The ink jet recording apparatus according to claim 1, wherein the ink is sucked into the ink container by abutting on the opening of the control unit.