JP2001315358A - Ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a quantity of ink passing a filter increases proportional to the elongation of a product life and impurities pile up in the filter in accordance with the lapse of use years to clog the filter and obstruct the circulation of the ink in many cases, whereby the ink cannot be normally supplied to a recording head, an image quality is deteriorated and eventually the recording head is broken in some cases because of null discharging of the ink. SOLUTION: The ink jet recording apparatus has the recording means for discharging the ink thereby recording to recording sheets, an ink-storing means for storing the ink to be supplied to the recording means, an ink-collecting means for collecting the ink discharged from ink discharge ports of the recording means and supplying the ink again to the ink-storing means, a viscosity reducing means for reducing a viscosity of the collected ink, a detachable foreign matter-removing means for removing foreign matters included in the collected ink, and a flowmeter for measuring a flow rate of the collected ink.

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, and more particularly to reusing ink in an ink jet recording apparatus. It is.

[0002]

2. Description of the Related Art A recording apparatus having functions such as a printer, a copying machine, a facsimile, or a multifunction machine including a computer or a word processor, and a recording apparatus used as an output device of a workstation are made of paper or plastic based on image information. An image is recorded on a recording sheet such as a thin plate (for example, used for an OHP). Such a recording apparatus is classified into an ink jet type, a wire dot type, a thermal type, a thermal transfer type, a laser beam type, and the like according to a recording method of a recording unit to be used.

[0003] Among these methods, an ink jet recording apparatus (ink jet recording apparatus) performs recording by discharging ink from a recording head, which is a recording means, onto a recording sheet. It is easy, can record high-definition images at high speed, can record on plain paper without requiring special processing, running cost is low, and because it is a non-impact method, there is little noise, In addition, it has an advantage that it is easy to record a color image using multicolor inks.

FIG. 3 is a schematic diagram showing an ink flow path in an ink jet recording apparatus which is a conventional printer.

[0005] As shown in FIG. 3, 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 is closed, and the excess ink is
b is returned to the ink cartridge 103. At the time of ejection of the recording head 101, the air communication port 103a is opened.

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 is removed from the first buffer tank 10.
The liquid is sent to the recording head 101 via the recording head 101. 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]

In such a conventional ink jet recording apparatus, the ink discharged from the ink cartridge to the recording head and discharged from the discharge port of the recording head for recording or discharge recovery is reused. In such a case, it is necessary to suppress or compensate for changes in physical properties such as thickening due to evaporation of volatile components, and to remove impurities in the ink such as precipitates and dust caused by evaporation of the volatile components. Regarding the removal of these impurities, see, for example,
There are techniques disclosed in Japanese Patent Application Laid-Open No. 314705 and Japanese Patent Application Laid-Open No. 9-131895. However, in these conventional techniques, although effective in filtering impurities,
It cannot compensate for evaporated water and other volatile components. Therefore, when a color image, particularly a photographic image, is recorded, color reproducibility may be poor.

Further, when a filter is used as a foreign matter removing means used for removing impurities, for example, in a conventionally used system, the filter is immediately clogged, and the ink flow path resistance is reduced. It can increase and cause the system to malfunction. In such a case,
The filter must be replaced while the hands are dirty, and if the filter is replaced too frequently, it requires a great deal of effort, is less economical, and results in a long printing interruption. .

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 the 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 print head is not performed, and the print quality may be degraded, and the print head may be destroyed due to idle discharge of ink.

[0013] Accordingly, an object of the present invention is to solve such a problem in the prior art, to cope with the prolongation of the product life, to surely filter the impurities of the ink to be reused, and to use them for removing the impurities. The replacement life of the foreign matter removal means is long,
In addition, the present invention provides an ink jet recording apparatus capable of accurately knowing the replacement time, thereby preventing the deterioration of the image quality by keeping the ink circulation system normal, and preventing the destruction of the recording head due to idle discharge. is there.

Another object of the present invention is to provide an ink jet recording apparatus in which, even when water and other volatile components in the ink evaporate, the ink to be reused has no impurities and further improves color reproducibility. Is to do.

[0015]

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. Storage means for storing ink, ink recovery means for recovering the ink discharged from the ink discharge port of the recording means and supplying the ink to the ink storage means again, and thickening mitigation for reducing the viscosity of the recovered ink Means, removable means for removing foreign matter contained in the collected ink, and a flow meter for measuring the flow rate of the collected ink.

Further, in the ink jet recording apparatus of the present invention, the thickening alleviating means, the foreign matter removing means, and the flow meter have an ink flow path from the ink discharge port to the ink storage means as an ink recovery path, and an ink discharge port located upstream of the ink discharge port. In this case, the thickening alleviating means, the foreign matter removing means, and the flow meter are provided in this order from upstream in the ink recovery path.

Further, the ink jet recording apparatus of the present invention further comprises an ink flow rate comparing means for comparing the measurement result of the flow meter with a preset limit flow rate value, and a method in which the integrated flow rate of the flow meter exceeds the limit flow rate value. And a notifying means for notifying the user.

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

[0019]

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, ink recovery means for recovering the ink discharged from the ink discharge port of the recording means and supplying the ink to the ink storage means again, thickening alleviating means for reducing the viscosity of the recovered ink, A detachable foreign matter removing unit included in the ink, and a flow meter for measuring a flow rate of the collected ink. Assuming that the ink flow path leading to the storage means is an ink recovery path and the ink ejection port is upstream, the thickening alleviating means, the foreign matter removing means, and the flow meter are provided in this order from the upstream in the ink recovery path. The apparatus further includes an ink flow rate comparing means for comparing the measurement result of the flow meter with a preset limit flow rate value, and a notifying means for notifying when the integrated flow rate of the flow meter exceeds the limit flow rate value. Therefore, it is possible to reuse ink that has once passed through the ink discharge port at a higher level. Further, by providing the thickening reducing means in front of the foreign matter removing means, for example, when using a constitutional means of adding a suitable amount of volatile components of the ink as the thickening reducing means,
The impurities precipitated by the evaporation of the volatile components of the ink are redissolved and the impurities are reduced, so that the replacement life of the foreign matter removing means can be extended.

By compensating for the volatile components in the ink that have been lost by evaporation, the quality of the ink can be reused at a high level equivalent to that of virgin ink, and the color reproducibility of the recording apparatus can be improved to a high level. And can be kept at
By providing a flow meter for measuring the flow rate of the ink downstream of the thickening alleviating means and the foreign matter removing means with respect to the ink flow direction, as described above, the properties such as physical properties and the like at a high level equivalent to virgin ink The flow rate can be measured with stable ink, and the flow rate can be measured more accurately.
Further, it is preferable to include an ink flow rate comparing means for comparing the measurement result of the flow meter with a preset limit flow rate value, and a notifying means for notifying when the integrated flow rate of the flow meter exceeds the limit flow rate value. By filtering the ink, the amount of impurities deposited on the filter can be estimated, and the filter replacement time can be easily grasped.

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 a configuration of an ink circulation system of 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.
1, a suction pump 2 for sucking ink, an ink cartridge 3 for storing ink, a pressure sensor 4 for detecting the presence or absence of ink, and a print head 1 for receiving ink discharged from the print head 1. A cap 5 provided so as to be able to abut, a thickening moderator adding device 6 for replenishing a thickening moderating agent so as to mitigate an increase in viscosity of the ink, and a filter 7 for removing foreign substances contained in the ink A drive motor 8 for operating the cap 5 and the suction pump 2, a flow meter 9 provided downstream of the filter 7 with respect to the ink flow direction, and an ink flow comparing means 10 having an LED 10 '. It has an ink flow path as a circulation system.

In the ink circulation system of the ink jet recording apparatus according to 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, a suction pump 2 for sucking ink from a cap 5 for receiving ink discharged from an ink discharge port 13 of the recording head 1, a thickening moderator adding device 6, a filter 7 The ink flow path which reaches the ink cartridge 3 via the flow meter 9 having the ink flow rate comparing means 10 with the LED 10 'is the ink recovery path.

In the ink jet recording apparatus of the present invention, first, the recording head 1 is an ink jet recording means for discharging ink by 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 the ink ejection section of the recording head 1. As shown in FIG. In FIG. 2, the discharge port face 1 faces a recording sheet (not shown) at a predetermined interval (for example, about 0.5 to 2.0 mm).
2, a plurality of ink discharge ports 13 are formed at a predetermined pitch, and generate 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. An electrothermal converter 16 such as a heating resistor is provided. In this embodiment, the recording head 1 is mounted on the carriage in such a manner that the ink ejection ports 13 are arranged in a direction intersecting 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 collecting means for receiving and collecting 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 and 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. Further, 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 moderator adding device 6, and then,
The thickener is added to the filter 7 via the connection tube 36 from the thickener, and further connected to the flowmeter 9 via the connection tube 37, and to the ink cartridge 3 via the drain tube 38 and the like. ing. Further, the flow meter 9 is connected to an ink flow rate comparing means 10 having an LED 10 ′. Further, the suction tubes 33 and 34, the connection tubes 35, 36 and 37, and the drain tube 38 are made of a rubber-like elastic body such as silicone rubber having flexibility and elasticity, that is, a flexible body.

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. Further, the pressure sensor 4 detects the presence or absence of ink in the ink supply path, detects a change in ink flow as a change in pressure, and is connected to the ink cartridge 3 by a supply tube 31 and , From the pressure sensor 4 to the sub tank 11 by a supply tube 32. The supply tubes 31 and 32 are also formed of a rubber-like elastic body such as silicone rubber having flexibility and elasticity, that is, a flexible body.

The cap 5 for receiving the ink ejected from the recording head 1 is provided so as to be able to switch between contact and separation with the recording head 1 by driving a drive motor 8. Therefore, at the time of recording, the cap 5 is separated from the recording head 1 at a predetermined interval,
During the recovery process, the cap 5 was brought into contact with the recording head 1, the capping was performed, and the suction pump 2 was operated to apply a negative pressure to the ink ejection port 13 of the recording head 1 to increase the viscosity. Foreign matter such as ink, air bubbles, dust and the like is sucked out from the recording head 1 together with the ink, and is discharged. As described above, 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 cut off from the outside air. Can be prevented.

The sucked ink includes thickened ink that has dried and adhered around 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 filter 6 is for filtering and removing such foreign matter from the ink, and can be suitably formed from a fibrous material, a mesh-like material, or another appropriate material. The filter 6 is preferably provided detachably so that it can be replaced.

An ink jet recording ink is disclosed in, for example, Japanese Patent Publication No. 7-119378. This ink is composed of 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, the thickening moderator adding device 6 is for supplementing such an evaporating component, and a thickening moderating 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.

Since the replenishment position of the thickening agent is preferably immediately before the filter 7, the thickening agent adding device 6 for replenishing the thickening agent is provided immediately upstream of the filter 7. It is provided on the side. As described above, the filter 7 is for filtering foreign substances as impurities in the ink. In order to enhance the effect of removing the filter 7, it is best to keep the transmittance of the filter 7 high. Therefore, if the thickening moderating agent does not cause any inconvenience when replenished, it can be replenished before passing through the filter 7 to reduce, for example, deposits deposited by evaporation of volatile components of the ink. Filtration accuracy can be maintained as high as possible.

Further, the flow meter 9 is provided downstream of the thickening moderator adding device 6 and the filter 7 with respect to the ink flow direction. If the flow meter 9 is provided upstream of the thickening moderator addition device 6 and the filter 7, foreign substances such as thickened ink and impurities accumulate on the flow meter 9, so that an accurate ink flow rate cannot be measured. Instead, the flowmeter itself may be stuck and hinder the circulation of ink. Therefore, by providing the flow rate meter 9 downstream of the thickening moderator adding device 6 and the filter 7, it is possible to measure the flow rate of the ink which is close to the virgin ink which is not thickened and whose impurities are filtered by the filter 7. And the conventional problems can be prevented. Further, as the flow meter 9, other similar flow meters such as a magnetic flow meter and an electrode flow meter can be suitably used.

Ink flow rate comparing means 10 with LED 10 '
Indicates that the durable ink amount of the filter 7 is set in advance,
When the ink flow rate measured by the flow meter 9 is equal to or exceeds the durable ink amount of the filter 7, the ink flow rate comparing means 10 turns on the LED 10 'to urge the filter 7 to be replaced.

Further, the sub-tank 11 includes the recording head 1
The ink is supplied to the 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 circulation of ink will be described with reference to the ink cartridge 3 in the ink jet recording apparatus according to the present invention thus configured.

In FIG. 1, for example, at a home position of a carriage (not shown), the drive motor 8 is driven to cap the recording head 1 with the cap 5. At the same time, the drive motor 8 drives the suction pump 2, thereby applying a negative pressure to the ink ejection port 13 of the recording head 1. The ink in the ink cartridge 3 passes through the supply tube 31 and the pressure sensor 4 and flows into the recording head 1 via the sub tank 11. The ink exceeding the allowable amount of the sub tank 11 is sent from the suction tube 33 to the suction pump 2.

Of the ink sent from the sub-tank 11 to the recording head 1, the ink which is not used for recording an image but is sucked from the ink discharge port 13 by the negative pressure is also sent from the suction tube 34 to the suction pump 2. Can be

The ink discharged from the discharge port 23 of the suction pump 2 passes through the connection tubes 35, 36, 37 and the drain tube 38, and first, the volatile components in the ink are replenished by the thickening moderator adding device 6. Then, various foreign substances such as thickened ink and ink deposits are filtered by the filter 7, the flow rate is measured by the flow meter 9, and then returned to the ink cartridge 3 via the drain tube 38.

In the above-described embodiment, a pressure adjusting means such as an air communication port may be provided in the ink flow path of the ink cartridge 3. The circulation of ink balances the negative pressure in the ink supply path from the recording head 1 to the ink cartridge 3, the negative pressure in the ink cartridge 3, and the negative pressure in the ink recovery path from the suction pump 2 to the ink cartridge 3. In a system that is When the negative pressure difference is large, or when a sudden change in the negative pressure occurs, normal ink circulation may not be obtained. For example, when the negative pressure in the ink collection path is higher than the negative pressure in the ink cartridge 3, the ink does not flow into the ink cartridge 3 as it tries to stay in the ink collection path.

By providing a pressure adjusting means to balance the ink collection path and the negative pressure in the ink cartridge 3, the ink can be smoothly circulated.

As described above, according to the present invention,
When the ink that has reached the print head from the ink cartridge and is discharged from the discharge port of the print head for printing or is reused by ink recovery is used, replenish the volatile components of the ink containing water and evaporate the ink. By re-dissolving the precipitate deposited from the ink in the ink and filtering the ink, the foreign matter dissolved therein can be economically and effectively removed. Therefore, the quality of the reused ink can be improved, and a high image quality equal to that of the virgin ink can be maintained. Further, it is possible to more accurately determine the replacement time of the filter for removing impurities.

In addition, the reuse of ink reduces waste ink, increases the amount of ink actually used per cartridge,
Needless to say, it is possible to improve the economical efficiency as a result of reducing the running cost and to reduce the capacity of the waste ink absorber or reduce the size of the recording apparatus by eliminating the waste ink absorber.

(Others) The present invention can of course be applied to various ink jet recording apparatuses as long as they use 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 configuration and principle are described in, for example, 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.

The structure of the recording head may be a combination of ink discharge ports, liquid paths, and electrothermal converters (a linear liquid flow path or a right-angle liquid flow path) as disclosed in the above 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, a recording head fixed to the apparatus main body or an electric connection with the apparatus main body or ink from the apparatus main body when mounted on the apparatus main body. 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 a configuration of a printing apparatus to which the present invention can be applied, various forms of 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 type and number of the 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.

Further, as an embodiment of the ink jet recording apparatus applicable to the present invention, in addition to 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.

[0056]

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; ink storing means for storing ink to be supplied to the recording means; An ink recovery means for recovering the ink discharged from the ink discharge port of the means and supplying the ink to the ink storage means again; a thickening reducing means for reducing the viscosity of the recovered ink; Since the apparatus includes the detachable foreign matter removing means and the flow meter for measuring the flow rate of the collected ink, it is possible to reuse the ink once passed through the ink discharge port at a higher level. Further, by providing the thickening reducing means in front of the foreign matter removing means, for example, impurities precipitated by evaporation of the volatile components of the ink as the thickening relaxing means are redissolved and the impurities are reduced, and the foreign matter removing means is removed. Replacement life can be extended. By compensating for the volatile components in the ink that have been lost by evaporation, the quality of the ink can be reused at a high level equivalent to that of virgin ink, and the color reproducibility of the recording device can be maintained at a high level. Can be. Further, in the above configuration, by providing a flow meter for measuring the flow rate of the ink downstream of the thickening alleviating means and the foreign matter removing means in the ink flowing direction, as described above, the physical properties at the same high level as the virgin ink are provided. The flow rate can be measured with ink that is stable in properties such as the above, and the flow rate can be measured more accurately. Further, it is preferable to include an ink flow rate comparing means for comparing the measurement result of the flow meter with a preset limit flow rate value, and a notifying means for notifying when the integrated flow rate of the flow meter exceeds the limit flow rate value. This makes it possible to estimate the amount of impurities deposited on the filter due to the filtering of the ink, and easily grasp the time for replacing the filter.

According to a second aspect of the present invention, in the ink jet recording apparatus, the thickening alleviating means, the foreign matter removing means, and the flow meter use an ink flow path from the ink discharge port to the ink storage means as an ink recovery path, and If the exit is upstream,
Since the thickening mitigation means, foreign matter removing means, and flow meter are provided in this order from the upstream in the ink recovery path, it is necessary to measure the flow rate with an ink that is as high as virgin ink and that has stable properties such as physical properties. And the flow rate can be measured more accurately.

According to a third aspect of the present invention, there is provided an ink jet recording apparatus, comprising: an ink flow rate comparing means for comparing the measurement result of the flow meter with a preset limit flow rate value; Since there is provided a notifying means for notifying when the amount exceeds the threshold value, it is possible to estimate the amount of impurities deposited on the filter by filtering the ink, and easily grasp the time to replace the filter.

In the ink jet recording apparatus according to a fourth aspect of the present invention, the recording means generates heat energy for causing film boiling in 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 configuration diagram showing 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 6 Thickening agent adder 7 Filter 8 Drive motor 9 Flow meter 10 Ink flow rate comparison means 10 'LED 11 Subtank 12 Discharge port surface 13 Ink discharge port 14 Common liquid Chamber 15 Liquid path 16 Electrothermal converter 21, 22 Suction port 23 Outlet port 31, 32 Supply tube 33, 34 Suction tube 35, 36, 37 Connection tube 38 Drain tube 101 Recording head 102 Ink cartridge 103 Subtank 103 a Atmospheric communication port 103 b Ink outlets 104, 105 Buffer tank 106 Ink recovery tub 107 Filter kit 108, 109, 110 Pump

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsuaki Tsunamoto, Inventor 3- 30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Naofumi Inoue 3- 30-2 Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (72) Inventor Yoji Ara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takehiko Kasamatsu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kenji Kitahata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yoshiyuki Inaka 3-30-2, Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. (72) Inventor Takahiro Oide 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2C056 EA16 EA27 EB16 EB48 EB54 EC26 FA03 JA13 JC04 JC 07 KB16 KB26 KB37 KB40 KC02

Claims (4)

[Claims] A recording unit configured to eject ink to perform recording on a recording sheet; an ink storage unit configured to store ink to be supplied to the recording unit; and a unit configured to collect ink ejected from an ink ejection port of the recording unit. An ink collecting means for supplying the ink to the ink storage means again, a thickening reducing means for reducing the viscosity of the collected ink, a detachable foreign matter removing means included in the collected ink, An ink jet recording apparatus comprising: a flow meter for measuring a flow rate. 2. The method according to claim 2, wherein said thickening alleviating means, foreign matter removing means, and flow meter have an ink flow path from the ink discharge port to the ink storage means as an ink recovery path, and the ink discharge port located upstream, the ink recovery path includes 2. The ink jet recording apparatus according to claim 1, wherein a viscosity increasing means, a foreign matter removing means, and a flow meter are arranged in this order from the upstream. 3. An ink flow rate comparing means for comparing a measurement result of the flow meter with a preset limit flow rate value, and a notifying means for notifying when an integrated flow rate of the flow meter exceeds the limit flow rate value. 3. The ink jet recording apparatus according to claim 1, wherein: 4. An apparatus according to claim 1, wherein said recording means includes an electrothermal transducer for generating thermal 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