JP2001315359A - Ink jet recording device - Google Patents

Abstract

(57) [Summary] [Problem] When a product has a long service life, the amount of ink passing through the filter increases in proportion to it, and as the years of use elapse, impurities accumulate on the filter and clogging occurs. However, since the circulation of the ink is hindered, the normal supply of the ink to the recording head is not performed, and the recording head is destroyed due to the deterioration of the image quality and the idle discharge of the ink. SOLUTION: In an ink jet recording apparatus having recording means for discharging ink to perform recording on a recording sheet, and ink storage means for storing ink to be supplied to the recording means, the ink discharged from the ink discharge port of the recording means is provided. An ink recovery means for recovering the recovered ink and supplying the ink to the ink storage means again, wherein a path for supplying the ink from the storage means to the recording means is an ink supply path, and the path from the ink discharge port to the ink storage means is provided. With the ink flow path as an ink recovery path, a first filter is provided in the ink supply path, and a second filter is provided in the ink recovery path.

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 for recording an image or the like by discharging ink from a recording means onto a recording sheet.
The present invention relates to a filter provided in an ink path for removing impurities, precipitates, and the like mixed in ink.

[0002]

2. Description of the Related Art An ink jet recording apparatus performs recording by discharging ink from a recording head as recording means onto a recording sheet, and is provided with an ink storage means such as an ink tank and a filter on the recording head and its peripheral portion. The filter is generally used to prevent ink clogging due to dissolved gas, eluted material, and the like generated in the ink, and is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-29837.

On the other hand, in order to reuse and use the ink generated at the time of recovery of the discharge of the recording head, a mechanism for collecting the ink once discharged from the discharge port and sending it to the ink storage means again is used. Some have.

FIG. 4 is a schematic configuration diagram showing an ink flow path in an ink jet recording apparatus such as a conventional printer having an ink recovery path for reusing ink.

[0005] As shown in FIG. 4, a conventional ink jet recording apparatus includes a recording head 101 as recording means for discharging ink to perform recording, an ink cartridge 102 for storing a large amount of ink, and storing ink. A sub-tank 103, a first buffer tank 104 and a second buffer tank 105, a collecting tub 106 for receiving and collecting ink ejected from the recording head 101, a filter kit 107 for removing foreign matter, first, second, and It has an ink circulation system formed by the third pumps 108, 109 and 110.

In the ink circulation system of such a conventional ink jet recording apparatus, when the first pump 108 is rotated for a predetermined time in the direction of the arrow CCW (counterclockwise) shown in FIG.
The ink stored in the ink cartridge 102 is supplied to the sub-tank 10 via the first buffer tank 104.
3 is supplied. At this time, the air communication port 103a of the sub tank 103 is closed, and surplus ink is returned to the ink cartridge 103 from the surplus ink discharge port 103b. At the time of ejection of the recording head 101, the air communication port 103a is open.

On the other hand, when the first and second pumps 108 and 109 are rotated in the illustrated CW direction (clockwise), the ink stored in the sub-tank 103 passes through the first buffer tank 104 and the recording head 101. Liquid. The fed ink is returned to the sub tank 103 via the second buffer tank 105 again.

[0008] The ink discharged from the recording head 101 is received by an ink collecting tub 106 and is supplied to a third pump 11.
After removing foreign matter such as dust by the filter kit 107 according to 0, the dust is returned to the sub tank 103.

[0009]

However, in such a conventional ink jet recording apparatus, the ink that has reached the recording head from the ink cartridge and is discharged from the discharge port of the recording head for discharge or discharge recovery for recording. When reusing, it is necessary to remove impurities such as thickened ink due to evaporation of volatile components. These impurities are water and other volatile components of the ink which evaporate, are thickened ink adhered to the ink flow path, deposits of the ink flow path forming member, and the like, and are often dissolved in the recovered ink. . Regarding the removal of these impurities, for example, JP-A-7-314705 and JP-A-9-131895
There is a technique disclosed in Japanese Unexamined Patent Publication (Kokai) No. H10-26095.

[0010] On the other hand, interest in environmentally conscious products has been increasing along with an increase in environmental protection consciousness, and contrivances have been made to extend the life of products and suppress generation of wastes as well as power saving and recycling. .

When the life of a product is prolonged, the amount of ink passing through the filter increases proportionally. In the related art, there are many cases in which impurities accumulate on the filter as the years of use elapse, causing clogging and preventing the circulation of ink. For this reason, normal supply of ink to the printhead is not performed, and the print quality may be degraded, or the printhead may be broken due to idle discharge of ink.

In order to prevent these problems, it is necessary to replace the filter when the filter reaches the limit. However, in an ink jet recording apparatus having a complicated structure, the replacement of the filter is very troublesome. It is a tedious and time-consuming task.

[0013] Accordingly, an object of the present invention is to solve such a problem in the prior art, in order to cope with the prolongation of the life of a product and to surely filter out impurities in the ink to be reused. To reduce the degree as much as possible, for that purpose, the filter provided in the ink path is composed of a plurality of filters having different fiber diameters, and when filtering impurities and precipitates, etc., a filter corresponding to the size is used. It is an object of the present invention to provide an ink jet recording apparatus in which the degree of clogging of one filter due to impurities, precipitates, and the like is reduced to extend the durable time.

[0014]

Therefore, in order to achieve the above-mentioned object, an ink jet recording apparatus according to the present invention comprises a recording means for discharging ink to record on a recording sheet, and an ink supplied to the recording means. And an ink storage unit for storing ink. The ink storage unit further includes an ink recovery unit that recovers ink discharged from an ink discharge port of the recording unit and supplies the ink to the ink storage unit again. A first filter in the ink supply path, wherein a path for supplying ink to the recording means is an ink supply path, and an ink flow path from the ink discharge port to the ink storage means is an ink recovery path; A second filter is provided in the path.

Further, in the ink jet recording apparatus according to the present invention, the average diameter of the first filter is smaller than the average diameter of the second filter.

Further, the ink jet recording apparatus of the present invention is characterized in that the second filter comprises a plurality of filter members.

Still further, in the ink jet recording apparatus according to the present invention, the second filter constituted by the plurality of filter members is arranged in the ink recovery path in the order from the ink ejection port to the filter member having the larger average diameter. It is characterized by being arranged.

An ink jet recording apparatus according to the present invention is characterized in that the ink collecting path has a means for relaxing the thickened ink.

Further, in the ink jet recording apparatus according to the present invention, the easing means may be configured so that the second means in the ink recovery path is provided.
The filter is disposed closer to the ink ejection port than the filter.

Further, the ink jet recording apparatus of the present invention is characterized in that the first filter and the second filter are made of a fibrous substance.

Still further, in the ink jet recording apparatus according to the present invention, the recording means may include an electric heat generating element for generating energy used for discharging the ink, the element generating heat energy for causing film boiling of the ink. A converter is provided.

[0022]

According to the ink jet recording apparatus of the present invention configured as described above, recording means for discharging ink to perform recording on a recording sheet, and ink storage for storing ink to be supplied to the recording means Means for recovering ink ejected from an ink discharge port of the recording means and supplying the ink to the ink storage means again, and supplying the ink from the storage means to the recording means. A supply path is an ink supply path, an ink flow path from the ink discharge port to the ink storage means is an ink recovery path, a first filter is provided in the ink supply path, and a second filter is provided in the ink recovery path. , The average diameter of the first filter is smaller than the average diameter of the second filter, and the second filter
Is composed of a plurality of filters, and a second filter composed of the plurality of filters is arranged in the ink recovery path in order from a filter having a larger average diameter from the ink discharge port side. ,further,
In the ink recovery path, there is provided a means for mitigating the thickened ink, wherein the relief means is disposed closer to an ink ejection port than the second filter in the ink recovery path, and And the second filter are both made of a fibrous substance.

With such a configuration, in the ink jet recording apparatus of the present invention, the service life of each filter is prolonged, and the number of replacements of each filter can be extremely reduced as a whole of the recording apparatus. The impurities deposited by evaporation are re-dissolved to reduce the impurities, thereby extending the replacement life of the filter, and compensating for the volatile components in the ink that have been evaporated and lost, thereby improving the quality of the ink at a high level. It becomes reusable, and color reproducibility as a recording device can be maintained at a high level.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of several embodiments of the present invention taken in conjunction with the accompanying drawings.

Hereinafter, the ink jet recording apparatus of the present invention will be described in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic diagram showing the configuration of an ink circulation system in an ink jet recording apparatus according to the present invention.

As shown in FIG. 1, an ink jet recording apparatus according to the present invention comprises a recording head 1 as recording means for performing recording by discharging ink, a cap 5 and a sub tank 1.
Suction pump 2 provided for sucking ink from 1
An ink cartridge 3 for storing ink, a pressure sensor 4 for detecting the presence or absence of ink, a cap 5 provided to be able to abut against the recording head 1 so as to receive ink ejected from the recording head 1, A thickening / mitigating means 7 for replenishing a thickening agent so as to mitigate an increase in viscosity of the ink from the suction pump 2, a cap 5, and a suction pump 2
, A first filter 9 for removing foreign substances contained in the ink supplied from the sub tank 11 to the recording head 1, and ink supplied from the suction pump 2 via the thickening alleviating means 7. And a sub-tank 11 for supplying ink from the ink cartridge 3 to the recording head 1 as an ink circulation system.

In the ink circulating system of the ink jet recording apparatus of the present invention, the recording head 1 is moved from the ink cartridge 3 as the ink storage means via the pressure sensor 4.
Is an ink supply path, and the ink cartridge 3 passes through the suction pump 2, the thickening alleviating means 7, and the second filter 10 from the cap 5 that receives the ink discharged from the ink discharge port 13 of the recording head 1. Is an ink recovery path.

In the ink jet recording apparatus according to the present invention, first, the recording head 1 is an ink jet recording means for discharging ink using thermal energy, which is provided with an electrothermal converter for generating thermal energy. It is. In addition, the recording head 1 performs recording by discharging ink from the ink discharge port 13 by utilizing a pressure change generated by growth and shrinkage of bubbles caused by film boiling generated by thermal energy applied by the electrothermal transducer. Things.

FIG. 2 is a partial perspective view schematically showing the structure of such an ink ejection section of the recording head 1. As shown in FIG. In FIG. 2, a plurality of ink discharge ports 1 are disposed at a predetermined pitch on a discharge port surface 12 facing a recording sheet (not shown) at a predetermined interval (for example, about 0.5 to 2.0 mm).
3 are formed, and an electrothermal converter 16 such as a heating resistor for generating energy for ink discharge along a wall surface of each liquid path 15 communicating the common liquid chamber 14 and each ink discharge port 13.
Are arranged. In this embodiment, the recording head 1
Are mounted on the carriage in a positional relationship such that the ink discharge ports 13 are arranged in a direction crossing the scanning direction of the carriage (not shown). In this way, by energizing and driving the corresponding electrothermal transducer 16 based on the image signal or the ejection signal, the ink in the liquid passage 15 is film-boiling, and the ink generated from the ink ejection port 13 by the pressure generated at that time. A printing head 1 that performs printing by discharging is configured.

Referring again to FIG. 1, in the ink circulation system of the ink jet recording apparatus of the present invention, an ink recovery means for receiving and recovering the ink discharged from the ink discharge port 13 of the recording head 1 by the cap 5. The suction pump 2 is for circulating the ink in the circulation path in the present ink circulation system, and has two suction ports 21,
22 and one outlet 23.

A suction tube 33 is attached to the suction port 22 of the suction pump 2 so that the sub tank 1
1, and a suction tube 34 is attached to the other suction port 21 and is connected to the cap 5. A connection tube 35 is attached to the outlet 23 of the suction pump 2, and the connection tube 35 is first connected to the thickening / mitigating means 7 such as a thickening / mitigating agent adder, and then Immediately from the thickening alleviating means 7, it is connected to the second filter 10, and further connected to the ink cartridge 3 via a connection tube 36 and a drain tube 37. In addition, these suction tubes 3
Like the supply tubes 31 and 32, the connection tubes 35 and 36, the drain tubes 37, and the like are made of a rubber-like elastic body such as silicone rubber, that is, a flexible body.

Further, the ink cartridge 3 is connected via a supply tube 31, a pressure sensor 4 and a supply tube 32 to a sub-tank 11 on a carriage (not shown) on which the recording head 1 is disposed. The supply tubes 31 and 32 are made of a rubber-like elastic body such as silicone rubber having flexibility and elasticity, that is, a flexible body.

The pressure sensor 4 detects the presence or absence of ink in the ink supply path, and detects a change in ink flow as a change in pressure.

The cap 5 is provided so as to be able to switch between contact and separation with the recording head 1 by driving the drive motor 8. Therefore, this cap 5
By operating the suction pump 2 to apply a negative pressure to the ink ejection port 13 of the recording head 1 in a state where the ink is in contact with the recording head 1, that is, in a capped state, the ink, the air bubbles, and the dust having increased viscosity And the like are sucked out from the recording head 1 together with the ink, and are discharged. In this way, the cap 5 covers the ink ejection port 13 of the recording head 1 when not in use, and the surface of the ink ejection port 13 of the recording head 1 is shut off from the outside air to prevent thickening of the ink and ink sticking due to natural evaporation. Is what you can do.

The sucked ink includes thickened ink that has dried and adhered to the periphery of the ink discharge port 13 of the recording head 1, paper powder that has been sprayed during conveyance of the recording sheet and adhered to the recording head 1, Various foreign substances such as ink deposits are included. The second filter 10 is for removing such foreign matter by filtering from the ink, and such a second filter 10 is preferably provided detachably so that it can be replaced.

An ink for ink jet recording is disclosed in, for example, Japanese Patent Publication No. 7-119378. This ink comprises a plurality of dyes, glycerin, urea, isopropyl alcohol (hereinafter referred to as "IPA"), and pure water. Have been.

The main reason for the thickening of the ink is evaporation of water and the like. However, as described above, volatile components such as IPA are also contained. It is necessary to supplement the ingredients. For example, a thickening / mitigating means 7 such as a thickening / mitigating agent adder is provided to compensate for the evaporation component, and a thickening / mitigating agent suitable for the ink composition is set and replenished here. In the case of the ink, the main volatile components are water and IPA, and a mixture of pure water and IPA is replenished according to the evaporation ratio.

The replenishment position of such a thickening agent is the second position.
It is preferred immediately before the filter 10, that is, a thickening-mitigating means 7 for replenishing the thickening-mitigating agent is provided immediately upstream of the second filter 10. As described above, the second filter 10 is for filtering foreign substances as impurities in the ink, and it is best to maintain high transmittance of the second filter 10 in order to enhance the removal effect. is there. Therefore, if the thickening agent is not replenished and has no inconvenience, by replenishing it before passing through the second filter 10, it is possible to reduce the precipitate deposited by evaporating the volatile component of the ink, for example. The filtering accuracy of the filter 10 can be maintained as high as possible, which is even more preferable.

The first filter 9 is provided between the recording head 1 and the sub tank 11. Therefore, the ink
The ink is supplied from the ink cartridge 3 to the sub-tank 11 via the supply tube 31, the pressure sensor 4, and the supply tube 32 in the ink supply path.
When the ink is supplied to the recording head 1 through the filter 9, foreign matter such as impurities contained in the ink is removed from the first filter 9.
Is removed by filtration.

Further, the sub-tank 11 supplies ink to the recording head 1 via the first filter 9 and is connected to the above-mentioned suction pump 2 via a suction tube 33. As a result, the ink level in the sub-tank 11, that is, the water level can be kept constant, a negative pressure within a certain range can always be secured, and good recording by the recording head 1 can be maintained.

Next, the diameter of the first filter 9 and the second filter 10, that is, the size of the mesh of the filter will be described. Hereinafter, the diameter of the filter refers to the size of the eye of the filter.

First, with respect to the first filter 9, the recording head 1 from the ink cartridge 3 via the ink supply path is used.
Is the last filter until the ink reaches.

For the second filter 10, the ink cartridge 3 passes from the ink discharge port 13 of the recording head 1 through the cap 5 in the ink recovery path, the suction pump 2, the viscosity increasing means 7, and the second filter 10. This is a filter for filtering the ink before the ink is stored until it is stored, and is for filtering the ink collected by suction. As described above, the thickened ink dried and adhered around the ink ejection port 13 of the recording head 1 and the paper powder adhered to the recording head 1 by spraying during conveyance of the recording sheet are applied to the sucked ink. And various foreign substances such as ink deposits and the like, and there is generally a high possibility that impurities are mixed in.

Therefore, it is preferable to use a small-diameter filter for the first filter 9 and a large-diameter filter for the second filter 10. In this way, the second filter 10 filters the large volume impurities, and the filtered ink is stored in the ink cartridge 3. Thereby, the first
With respect to the ink filtered by the filter 9, only small impurities having a small volume that cannot be completely filtered by the second filter 10 arrive. That is, as the size, the relationship of the diameter of the first filter <the impurity to be filtered <the diameter of the second filter is established. Accordingly, in the present embodiment, the relationship of the aperture of the first filter <the aperture of the second filter is established in the size of the apertures of the first and second filters. By configuring the first and second filters, large impurities and precipitates that are likely to be generated due to having an ink recovery path can be removed due to the difference in the size of impurities to be filtered by the first and second filters. Second filter 10
Thus, the service life of the first filter 9 and, accordingly, the service life thereof can be further increased.

The diameter of the first filter 9 is about 5 μm.
By doing so, a good filtration effect can be obtained without significantly lowering the fluid resistance. On the other hand, for the second filter 10,
By making the diameter of the filter about 15 μm,
Suitable for removing large impurities. In this case, impurities having a size of about 5 μm to 15 μm are filtered by the first filter 9, and relatively large ones having a size of about 15 μm or more are filtered by the second filter 10. Although it is assumed that the impurities are uniformly filtered by the first and second filters 9 and 10, depending on the size ratio of the impurities, the life of the first and second filters 9, 10 is as follows. The service life is about twice as long. Therefore,
It is preferable to optimize the diameter of each of the first and second filters 9 and 10 in consideration of the configuration of the ink jet nozzle, the ejection amount, the size of impurities due to ejection recovery, and the like.

(Embodiment 2) FIG. 3 is a schematic diagram showing the configuration of an ink circulation system in Embodiment 2 of an ink jet recording apparatus to which the present invention is applied.

The basic configuration of this embodiment is the same as that of the first embodiment.
And the detailed description is omitted. In the ink circulation system according to the second embodiment of the ink jet recording apparatus of the present invention shown in FIG. 3, the ink flow path from the ink cartridge 3 as the ink storage means to the recording head 1 via the pressure sensor 4 and the sub tank 11 is an ink supply path. And the ink ejection port 13 of the recording head 1
The ink flow path from the cap 5 that receives the ink discharged from the ink cartridge 3 through the suction pump 2, the viscosity reducing means 7, and the second filter 40 to the ink cartridge 3 is an ink recovery path.

In FIG. 3, the second filter 40 forms a filter group composed of a plurality of filter members. As shown, the second filter 40 has five filter members 41 and 42. , 43, 44, 45. These filter members 41, 42, 43, 4
4, 45 are each filter member 41, 42, 43, 44,
45 are arranged such that the following relationship is established. That is, each of the filter members 41, 42,
The diameter of 43, 44, 45 is Φ41, Φ42, Φ43, Φ
Assuming that 44 and Φ45, the arrangement is such that Φ41>Φ42>Φ43>Φ44> Φ45. Further, regarding the relationship with the aperture of the first filter 9, when the aperture of the first filter 9 is Φ1, the relationship Φ1 <Φ45 is satisfied.

As described above, in this embodiment, by arranging a multi-stage filter composed of a plurality of filter members, the service life per filter member is prolonged.

In this embodiment, the second filter 40 is composed of five filter members 41, 42, 43, 44, 45. However, when the nozzle used for ejection or the ejection recovery is performed, It is desirable to optimize the number and diameter of the filter members according to the size distribution of impurities and the like mixed into the ink.

As described above, in the ink jet recording apparatus of the present invention, by providing a plurality of filters in the ink circulation path, the service life of one filter is lengthened, and the filter is replaced as a whole of the recording apparatus. The number of times can be extremely reduced.

In addition, since the second filter is constituted by a plurality of filter members, the service life of the filter can be increased in filtering out impurities and precipitates which are likely to be generated in a printer employing an ink recycling path. And
It is possible to drastically reduce the number of filter replacements.

(Others) It should be noted that the present invention can be applied to various ink jet recording apparatuses as long as it uses ink as a recording agent. Among them, the present invention is used for discharging ink. Means for generating thermal energy as energy (for example, an electrothermal converter or a laser beam) are provided, and a superior effect is obtained in a recording head and a recording apparatus of a type in which a change in ink state is caused by the thermal energy. . According to such a method, it is possible to achieve higher density and higher definition of recording.

The typical structure and principle are described in, for example, US Pat. No. 4,723,129 and US Pat.
It is preferable to use the basic principle disclosed in the specification of US Pat. No. 740,796. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or the liquid path holding the liquid (ink). By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer or the like, heat energy is generated in the electrothermal transducer and recording is performed. This is effective because film boiling occurs on the heat-acting surface of the head, and consequently bubbles in the liquid (ink) can be formed corresponding to this drive signal on a one-to-one basis. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet.
When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. U.S. Pat. No. 4,463,359 describes this pulse-shaped drive signal.
Nos. 4,345,262 are suitable. It should be noted that U.S. Pat.
If the conditions described in the specification of JP-A No. 4 are adopted, more excellent recording can be performed.

As a configuration of the recording head, a combination configuration (a linear liquid flow path or a right-angled liquid flow path) of an ink discharge port, a liquid path, and an electrothermal converter as disclosed in each of the above-mentioned specifications.
In addition to the above, a configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600 which discloses a configuration in which a heat acting portion is arranged in a bending region is also included in the present invention. Included. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads, or a configuration as one integrally formed recording head.

In addition, even in the case of the serial type as described above, when the recording head is fixed to the apparatus main body or is attached to the apparatus main body, the recording head is electrically connected to the apparatus main body and ink from the apparatus main body is discharged. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is provided integrally with the recording head itself is used.

Further, as the configuration of the printing apparatus to which the present invention can be applied, various forms of the ejection recovery means (including preliminary auxiliary means and the like) of the printing head may be used. Specifically, capping means for the recording head,
A cleaning means such as a blade, a means for removing ink from the ink ejection port by pressurizing the ink supply system or suctioning as described above, an electrothermal converter, a separate heating element, or a combination thereof. Any means may be used as long as it includes a preliminary heating means for performing heating by heating and a preliminary ejection means for performing ejection other than recording. When ink adhesion or residue may occur on the head face after such recovery processing, the arrangement of the absorber in the cap as in this example is effective, and the absorber for keeping the blade clean is effective. This is because the arrangement can prevent the ink from dropping to an undesired portion.

Regarding the types and the number of recording heads to be mounted, for example, in addition to the recording head having only one corresponding to a single color ink, a plurality of recording heads having different recording colors and densities as described above are provided. A plurality of recording heads may be provided for each ink. That is, for example, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, but may be any of integrally forming a printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the full-color recording modes using mixed colors.

In addition, in the embodiment of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature may be used. In general, the ink jet method generally controls the temperature of the ink itself within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. Sometimes, the ink may be in a liquid state. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start solidifying when it reaches the recording medium. The present invention is also applicable to a case where an ink that liquefies for the first time is used. In such a case, the ink is disclosed in JP-A-54-56847 or JP-A-60
As described in JP-A-71260, a configuration may be adopted in which a liquid or solid substance is held in a concave portion or through hole of a porous sheet and opposed to an electrothermal converter. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition to the above, examples of the form of the ink jet recording apparatus applicable to the present invention include those used as image output terminals of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and a facsimile having a transmission / reception function. It may be in the form of an apparatus.

[0063]

According to the first aspect of the present invention, there is provided an ink jet recording apparatus comprising: recording means for discharging ink to perform recording on a recording sheet; and ink storing means for storing ink to be supplied to the recording means. The recording apparatus further includes an ink recovery unit that recovers the ink discharged from the ink discharge port of the recording unit and supplies the ink to the ink storage unit again. A first filter is provided in the ink supply path, and a second filter is provided in the ink recovery path. The first filter is provided in the ink supply path, and the ink flow path from the ink discharge port to the ink storage means is used as the ink recovery path. Therefore, the service life of each filter is prolonged, and the number of times of replacement of each filter can be extremely reduced as a whole of the apparatus. The impurities deposited by the evaporation of the solvent are redissolved to reduce the impurities, thereby extending the replacement life of the filter. It becomes reusable, and color reproducibility as a recording device can be maintained at a high level.

In the ink jet recording apparatus according to the second aspect of the present invention, the average diameter of the first filter is smaller than the average diameter of the second filter. And the like can be filtered and removed, and high-quality and clear recording can be performed.

In the ink jet recording apparatus according to the third aspect of the present invention, since the second filter is composed of a plurality of filter members, a filter having good filtration performance can be easily formed and the cost can be reduced. Can be manufactured.

The ink jet recording apparatus according to claim 4, wherein the second filter comprising the plurality of filter members has a filter member having a large average diameter from an ink discharge port in the ink recovery path. Are arranged in this order, so that impurities, precipitates and the like can be satisfactorily filtered and removed.

Since the ink jet recording apparatus according to the fifth aspect of the present invention has means for relaxing the thickened ink in the ink recovery path, impurities deposited by evaporation of volatile components of the ink are re-dissolved. It will reduce impurities, extend the replacement life of the filter, make up for the volatile components in the ink lost due to evaporation, and re-use the ink quality at the same high level as virgin ink,
Color reproducibility as a recording device can be maintained at a high level.

According to a sixth aspect of the present invention, in the ink jet recording apparatus, since the easing means is disposed closer to the ink ejection port than the second filter in the ink recovery path, the ink ejection port is once used. It is possible to reuse the ink that has passed through the ink at a higher level, and as a means for reducing the viscosity, impurities deposited by evaporation of the volatile components of the ink are redissolved, and the impurities are reduced, thereby extending the replacement life of the filter. be able to.

In the ink jet recording apparatus according to the present invention, since the first filter and the second filter are made of a fibrous substance, the filters can be simply constructed and can be manufactured at low cost. .

According to an eighth aspect of the present invention, in the ink jet recording apparatus, the recording means generates thermal energy for causing film boiling of the ink as an element for generating energy used for discharging the ink. Since the electrothermal transducer is provided, it is possible to discharge ink satisfactorily and record finely.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of an ink circulation system in a first embodiment of an inkjet recording apparatus to which the present invention is applied.

FIG. 2 is an exploded perspective view schematically showing a structure of an ink ejection unit of the recording head shown in FIG.

FIG. 3 is a schematic diagram illustrating a configuration of an ink circulation system in a second embodiment of the inkjet recording apparatus to which the present invention is applied.

FIG. 4 is a schematic configuration diagram illustrating a conventional liquid connection structure of an ink circulation system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording head 2 Suction pump 3 Ink cartridge 4 Pressure sensor 5 Cap 7 Thickening relief means 8 Drive motor 9 1st filter 10 2nd filter 11 Sub tank 12 Discharge port surface 13 Ink discharge port 14 Common liquid chamber 15 Liquid path 16 Electric heat Converter 21, 22 Suction port 23 Drain port 31, 32 Supply tube 33, 34 Suction tube 35, 36 Connection tube 37 Drain tube 40 Second filter 41, 42, 43, 44, 45 Filter member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naofumi Inoue 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Yoji Ara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside (72) Inventor Yoshiyuki Imanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Koichi Okado 3-30-2, Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. ( 72) Inventor Katsuaki Tsunamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Nei Kochi 3-30-2, Shimomaruko 3-chome, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Kenji Kitabatake 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2C056 EA14 EA19 EA21 EA24 EA26 EA27 EB54 FA03 FA10 JA13 JC04 JC20 KB16 KB26 KB37 KB40 KD10

Claims (8)

[Claims] 1. An ink jet recording apparatus comprising: recording means for discharging ink to record on a recording sheet; and ink storage means for storing ink to be supplied to the recording means. An ink collection unit that collects the collected ink and supplies it to the ink storage unit again, wherein a path for supplying the ink from the storage unit to the recording unit is an ink supply path, and the ink discharge port supplies the ink to the ink storage unit. An ink jet recording apparatus, comprising: a first filter in the ink supply path, and a second filter in the ink recovery path, with an ink flow path leading to the ink recovery path. 2. The ink jet recording apparatus according to claim 1, wherein the average diameter of the first filter is smaller than the average diameter of the second filter. 3. The ink jet recording apparatus according to claim 1, wherein the second filter is composed of a plurality of filter members. 4. The filter according to claim 1, wherein the second filter including the plurality of filter members is arranged in the ink recovery path in the order of a filter member having a larger average diameter from an ink discharge port side. The ink jet recording apparatus according to claim 1, wherein 5. The ink jet recording apparatus according to claim 1, further comprising means for relaxing the thickened ink in the ink recovery path. 6. The ink jet recording apparatus according to claim 1, wherein said mitigation means is arranged closer to an ink discharge port than said second filter in said ink recovery path. 7. The ink jet recording apparatus according to claim 1, wherein the first filter and the second filter are made of a fibrous substance. 8. The recording device according to claim 1, wherein said recording means includes an electrothermal transducer for generating heat energy for causing film boiling of the ink as an element for generating energy used for discharging the ink. The ink jet recording apparatus according to claim 1, wherein