JP2006056114A - Recorder and method of recovering inkjet recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recorder capable of reducing a processing time period before recording relating to a recovery operation for an inkjet recording head and improving a total throughput relating to recording of an image, and a method of recovering the inkjet recording head. <P>SOLUTION: One of the plurality of recovery operations having different filling amounts of ink is selected in order to recover the inkjet recording head based on a detected residual amount of the ink and a time period elapsed from the previous recording operation. When the selected recovery operation is carried out, an ink-filling speed for filling the ink is varied depending on the selected recovery operation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a recording apparatus and an ink jet recording head recovery method, and in particular, uses two ink tanks having different capacities and intermittently supplies ink from a large capacity ink tank to a small capacity ink tank directly connected to the recording head. The present invention relates to a recording apparatus and an ink jet recording head recovery method that employ an intermittent ink supply method.

  An ink jet recording apparatus (hereinafter referred to as a recording apparatus) that forms an image on a recording medium by ejecting ink onto the recording medium using an ink jet recording head (hereinafter referred to as a recording head) includes a recording head fixed to the apparatus. On the other hand, image formation is performed by ejecting ink in the process while transporting and moving the recording medium, or ink ejection is performed in the process while moving the recording head to the fixed recording medium, and then the recording medium is moved In some cases, image forming is performed by so-called serial scanning, which is repeated a plurality of times, but recently, the serial scanning type has become mainstream.

  In a serial scan type recording apparatus, many means have been proposed and put to practical use as means for supplying ink to a recording head. However, as one of the ink supply methods, an ink tank on the recording apparatus side is used. There is a method for supplying ink to a recording head mounted on a carriage via a tube (hereinafter referred to as a tube supply method). However, according to such a tube supply method, the movement of the tube accompanying the movement of the carriage may affect the flow of ink in the tube in the movement direction of the carriage, and ink ejection from the recording head may become unstable. is there. For this reason, in order to shorten the discharge interval from the predetermined nozzle of the recording head and increase the recording speed, it is necessary to suppress the oscillation of the ink in the tube so that the ink discharge does not become unstable.

  In addition, the tube supply method has various disadvantages associated with the necessity of a tube having a length that allows the carriage to reciprocate.

  For example, when the recording apparatus is not used for a long period of time, in order to avoid problems due to air intrusion into the tube during that period, when using the recording apparatus, first the tube from an ink supply source such as an ink tank is used. It was necessary to distribute a large amount of ink inside. On the other hand, such a tube merely forms a path for supplying ink from the ink tank to the recording head. For a small added value, the size and cost of the recording apparatus are increased. The problem was that the structure was complicated.

  The so-called head tank-on-carriage system proposed to eliminate the ink supply tube is inseparably integrated with the recording head mounted on the carriage of the recording apparatus and reciprocating. Alternatively, an ink tank is attached so as to be separable, and ink is supplied from the ink tank to the recording head. Hereinafter, when referring to the head tank on carriage system, the carriage refers to the entire moving body including the recording head and the ink tank unless otherwise specified.

  Under such a head tank on carriage system, an ink supply path for supplying ink directly is formed between the recording head and the ink tank, so there is no need for an ink supply path using a tube. The configuration of the supply path can be made extremely simple. In addition, since the ink supply path is integrally included in the recording head or the ink tank, it is possible to reduce the size and cost. Furthermore, the ink supply path itself can be designed to be short, and the distance of the ink supply path that is parallel to the carriage movement direction in the ink supply path can be greatly reduced. It is possible to effectively suppress the situation where the ink ejection becomes unstable due to the oscillation of the ink in the path.

  However, such a head tank-on-carriage system increases the size and weight of the entire carriage including the recording head and the ink tank when the capacity of the ink tank is increased or the number of ink colors used for recording is increased. In other words, this leads to an increase in the size of a motor serving as a drive source for the carriage, an increase in driving power, and an increase in the size and weight of the entire recording apparatus.

  That is, the inertial force at the time of carriage movement increases in proportion to the increase in the carriage weight. Therefore, in order to move the carriage at a high speed against the inertial force, the driving power of the carriage is large. It is necessary to provide a high output device, leading to an increase in the price of the entire recording apparatus. As the carriage weight increases, the force for stopping the carriage increases against the inertial force when reversing the moving direction in carriage reciprocating scanning, and the entire recording apparatus vibrates greatly due to the reaction force of the force. Problem arises.

  On the other hand, if the printing device is to be reduced in size, price, or thickness, it is essential to make the carriage lighter or thinner. If the ink capacity of the ink tank is reduced, the frequency of ink tank replacement In the extreme case, the ink tank may need to be replaced during the recording operation. Also, considering the environment, frequent ink tank replacement is not preferable.

  As an ink jet supply system capable of solving these problems, an ink jet supply system that employs an intermittent ink supply system is known.

  For example, an intermittent ink supply method applied to a serial scan type printing apparatus includes a sub ink tank that accommodates a relatively small amount of ink and a printing head mounted on the carriage, and separately from this, the carriage of the printing apparatus. There is a main ink tank that accommodates a relatively large volume of ink in a portion other than the above, and the supply mechanism is configured so that ink is supplied from the main ink tank to the sub ink tank at an appropriate timing.

  Further, during carriage scanning, the ink supply system between the sub ink tank and the main ink tank is spatially separated, or the ink flow path is blocked by a valve or the like, so that the sub ink tank and the main ink tank A configuration that fluidly insulates them is employed. By adopting such a system, the occurrence of various problems due to tube swinging can be basically solved, and the sub ink tank on the carriage can be reduced in size, but the main ink tank is frequently used. The convenience of the user is not impaired without exchanging the password.

  One recording apparatus that employs such an intermittent ink supply method is disclosed in Patent Document 1. According to this prior art, a sealed biased bag type ink container is connected to the recording head, and if necessary, an auxiliary ink container is connected to the biased bag type ink container. Ink is supplied to the mold ink container. The bias bag type ink container is provided with a bag for containing ink, and the ink is contained in the bag under a negative pressure that suppresses leakage of ink from the ink discharge port of the recording head. Using this negative pressure, ink is supplied from the auxiliary ink container to the biased bag type ink container.

  The bag in this biased bag type ink container is crushed according to the amount of ink discharged from the recording head, that is, the amount of ink used, and the volume is reduced. When the volume of the bag is reduced to a predetermined amount or less, the supply port provided in the biased bag type ink container and the auxiliary ink container are connected. As a result, ink is supplied from the auxiliary ink container to the bag by the negative pressure in the bag of the biased bag type ink container. When the ink capacity in the bag becomes maximum, the negative pressure in the bag becomes “0”, and the ink supply is automatically stopped. Therefore, according to this prior art, it is possible to automatically stop the ink supply using the negative pressure without requiring control using a pressure sensor, a capacitance detection sensor, or the like.

  Incidentally, the upper limit of the negative pressure in the biased bag type ink container is determined by the balance with the ink ejection force when the recording head ejects ink. This is because if the negative pressure is too large, the ink discharge force of the recording head decreases due to the negative pressure, and ink cannot be discharged. Therefore, it is necessary to determine the negative pressure within the range of the best ink discharge conditions in the recording head. Also, the ink head position in the auxiliary ink container needs to be set lower than the ink head position in the biased bag type ink container. If the head difference is too large, the biased bag type ink is used. Even if the negative pressure in the container is determined in accordance with the ink discharge conditions of the recording head, ink cannot be supplied.

  Therefore, in this prior art, a special device is provided for setting the vertical height position of the auxiliary ink container relative to the biased bag type ink container. However, the provision of such an apparatus causes a problem that the recording apparatus main body is increased in size and cost. In addition, when a situation occurs in which air enters the ink flow path from a part of the ink flow path connecting the auxiliary ink container and the biased bag type ink container during ink replenishment, the air is biased. It moves into the bag of the bag type ink container, and the ink capacity of the biased bag type ink container decreases. Further, when the amount of air intrusion is large, there is a problem that the inside of the biased bag type ink container is filled with air, and it becomes impossible to supply ink again.

  In addition, for the problem of air mixing into the above-described biased bag type ink container, a method of reducing the gas and air permeability of the bag itself is also conceivable. Has also been proposed. According to this technique, in an intermittent ink supply method using a biased bag type ink container, after making the ink supply possible state, the air mixed in the bag is pressurized into the auxiliary ink container by pressurizing the bag from the outside. The ink is once back-flowed, and then normal ink supply is performed. In addition, since the ink is drawn by applying a negative pressure to the outside of the bag at the time of normal ink supply, the above-mentioned water head difference problem does not become a big problem.

  However, it is clear that the ink supply operation takes time if such a method is used. In addition, the biased bag type ink container is configured by using a movable member such as a spring member for inflating the bag member, or using an elastic bag member having low gas or air permeability as a stretchable bag member forming the bag. Therefore, there are limits to the cost reduction and miniaturization. As a result, while using the intermittent ink supply method, it is difficult to reduce the size of the apparatus and the structure is complicated, resulting in an increase in weight and cost of the apparatus.

  On the other hand, a recording apparatus as described in Patent Document 3 has also been proposed. In the configuration disclosed in this document, an air suction port is provided in the sub-tank above the recording head in addition to the ink supply port, and a semi-permeable membrane-like gas that allows air to pass but does not allow liquid to pass through the air suction port. A liquid separation member is provided, and when ink is supplied, the air in the sub tank is sucked from the suction port through the gas-liquid separation membrane with a suction pump or the like, and the pressure in the sub tank is reduced to supply ink from the main tank. Yes.

  According to this method, since the ink is supplied by suction using a suction pump or the like, the above-described problem of water head difference is not a big problem. Furthermore, since this gas-liquid separation member functions as a full valve, ink replenishment is automatically performed using a gas-liquid separation membrane without the need for separate control using a pressure sensor, a capacity detection sensor, or the like. Can be stopped. That is, when the ink is sufficiently supplied, the negative pressure in the sub-tank is eliminated and the ink supply is completed. However, since the gas-liquid separation film does not pass the ink, the ink in the sub-tank does not flow out from this film.

  Even when air is mixed into the sub tank, as in the case of using a biased bag type ink container, air is discharged from the sub tank through the gas-liquid separation film when supplying ink, and this adversely affects ink supply due to air mixing. This problem does not occur in principle. Further, the ink supplied into the sub tank is held by a negative pressure generating member such as a sponge. However, since the technique for generating the negative pressure by the sponge is often used in an ink jet recording apparatus, the negative pressure in the sub tank is There is also an advantage that there is a lot of knowledge in pressure management.

As a technique for actually realizing a small and thin recording apparatus using such a gas-liquid separation membrane, techniques described in Patent Document 4 and Patent Document 5 have been proposed.
Japanese Patent Laid-Open No. 9-24698 JP 2002-370374 A Japanese Patent Laid-Open No. 2000-334982 Japanese Patent Laid-Open No. 2004-74781 Japanese Patent Laid-Open No. 2004-74782

  However, in the prior art using the intermittent ink supply method, as an ink supply method, there are many methods in which the pressure in the sub tank is reduced and ink is introduced. Therefore, as disclosed in Patent Document 3, when the sub tank is depressurized to fill with ink, air enters the sub tank from the nozzle of the recording head where the meniscus should have been formed by the ink, and the meniscus is destroyed. It may be done. Even if the nozzle is sealed with a cap during the ink supply operation, if there is a space in the cap, the air in the space enters the sub tank from the nozzle.

  For such a problem, Patent Document 3 proposes to apply a predetermined negative pressure to the cap member side of the nozzle simultaneously with the ink supply operation.

  Alternatively, as proposed in Japanese Patent Application No. 2002-373443, when the negative pressure increase during ink filling is expected to be large, that is, in a low temperature environment where the ink viscosity is high and the ink flow resistance is large, It has also been proposed to change the control so that the ink is filled in such a way that the negative pressure does not easily rise when the amount of ink to be filled is large due to the small amount of residual ink. Specifically, control is performed so that the negative pressure does not increase excessively by slowing the suction speed of the air suction pump that decompresses the sub tank and supplying ink slowly.

  Further, when the intermittent ink supply method is used, the main tank and the sub tank are not connected except when ink is supplied, and naturally they are not connected even when the printing apparatus is not used. Therefore, if the recording apparatus is left for a long period of time with a small amount of ink held in the sub tank, the volatile component of the ink in the sub tank evaporates and the ink is concentrated. Since only a small amount of ink is stored in the sub-tank and is not connected to the main tank that stores a large amount of ink compared to the sub-tank, the degree of ink concentration in the sub-tank accompanying evaporation is normal. It becomes more remarkable than the recording apparatus of the head tank on carriage.

  Therefore, in Japanese Patent Application No. 2003-272069, when the ink in the sub tank is excessively concentrated, when the image is formed using the ink in the sub tank as it is, and when the image is formed using the ink that is not concentrated Since the color of the image is greatly different, the entire amount of concentrated ink in the sub-tank is once discharged, and then the non-concentrated ink (hereinafter also referred to as fresh ink) in the main tank is filled again. We have proposed a technique such as image formation after that. Furthermore, if the ink is left for a longer period of time, the ink viscosity in the sub tank will increase drastically, and normal recovery cannot recover the nozzle. Therefore, before the recovery, fill the sub tank with fresh ink in the main tank and then the nozzle. There has also been proposed a recovery method in which a suction recovery operation is performed, and the ink having increased viscosity in the vicinity of the nozzle is re-dissolved with the fresh ink and washed with friends.

  In order to reduce the amount of ink required for the recovery operation when performing the recovery method for washing with friends, instead of discharging all of the added fresh ink, the ink with increased viscosity is dissolved and the ink above the predetermined level is dissolved. It is sufficient to discharge only the ink having the density of. However, when the recording apparatus is left for a long time, if the ink viscosity in the vicinity of the nozzle is very increased, the ink with increased viscosity is difficult to flow, and the nozzle is clogged with the increased viscosity ink, Ink is not discharged. For this reason, it is difficult to accurately control the suction amount, and therefore, concentrated / unconcentrated mixed in the sub tank without discharging only high concentration ink or a predetermined amount (small amount) of the added fresh ink. The total amount of ink is sucked.

  The technology related to ink filling control for holding the meniscus of the nozzle during ink filling and the technology for recovery operation of the nozzle are essentially not correlated with each other, and the control is determined independently. It is good.

  However, for example, in the following cases, a series of pre-recording operations from ink filling to completion of the recovery operation may take time.

  Conventionally, if the nozzles need to be washed for a long time, the ink is first filled. If the temperature is low at this time, the ink is filled at a lower suction speed to protect the nozzle meniscus. It was. Thereafter, the ink is sucked and recovered from the nozzle, and the ink with increased viscosity near the nozzle is washed with fresh ink. At this time, the entire concentrated / unconcentrated mixed ink in the sub tank is sucked from the nozzle. Thereafter, the sub-tank is filled again with ink, and then a predetermined small amount of suction amount is restored to start actual recording.

  As can be seen from the above example, in the low temperature environment, even if the ink filling is performed so as to protect the meniscus by slowing down the suction speed of the pump, all the ink in the sub tank is discharged in the next nozzle washing process. Therefore, the meniscus is destroyed, and there is a case where it is meaningless to perform ink filling over a slow time because of a low temperature environment.

  Thus, the ink filling control that originally protects the meniscus and the nozzle recovery control are not correlated with each other, but when ink filling is used as part of the recovery sequence, The optimal ink filling method should be adopted according to the recovery method used in the recovery sequence and the order of recovery, and no proposal from such a viewpoint has been made conventionally. As a result, there is a case where the time required for ink filling and recovery before recording is unnecessarily long, and the total recording speed is lowered.

  The present invention has been made in view of the above-described conventional example, and a recording apparatus and an ink jet capable of shortening the pre-recording processing time related to the recovery operation of the ink jet recording head and improving the total throughput related to image recording. It is an object of the present invention to provide a recording head recovery method.

  In order to achieve the above object, the recording apparatus of the present invention has the following configuration.

  That is, a recording apparatus that performs recording using an inkjet recording head, wherein the first ink tank has a small capacity for supplying ink to the inkjet recording head, and is intermittently connected to the first ink tank, A large-capacity second ink tank that supplies ink to the first ink tank; suction means for performing suction to fill the first ink tank from the second ink tank; Detecting means for detecting the remaining amount of ink in one ink tank; measuring means for measuring the environmental temperature of the recording apparatus; timing means for measuring an elapsed time from a previous recording operation by the recording apparatus; and the detecting means In order to recover the ink jet recording head, the ink filling amount differs according to the remaining ink amount detected by the time and the elapsed time measured by the time measuring means. Select one of a plurality of recovery operations and control the suction unit to change the ink filling speed by the suction unit according to the selected recovery operation and the recovery unit that performs the selected recovery operation And a suction control means.

  Here, the ink filling speed further changes according to the detected remaining ink amount and the measured environmental temperature.

  Further, the ink jet recording head includes preliminary ejection means for performing preliminary ejection of ink, and the recovery means includes a plurality of recovery operations including the preliminary ejection according to the detected remaining ink amount and the measured elapsed time. It is desirable to select one of these and perform the recovery operation of the ink jet recording head.

  Further, when the recovery means selects preliminary ejection as the inkjet recovery operation, the suction control means fills ink by the suction means during the preliminary ejection according to the detected remaining ink amount and the measured environmental temperature. It is desirable to control the suction means to change the speed.

  The suction means includes a suction pump, and after the first ink tank and the second ink tank are connected, the suction pump depressurizes the inside of the first ink tank, so that the first ink tank removes the first ink tank from the first ink tank. Fill the ink tank with ink.

  The plurality of recovery operations include a first recovery operation involving suction of a part of the first ink tank, a second recovery operation involving suction of the entire amount of ink in the first ink tank, and a second recovery operation. Ink supply from the ink tank and a third recovery operation involving suction of the entire amount of ink in the first ink tank.

  Furthermore, the ink filling speed has a characteristic that the lower the environmental temperature and the lower the ink remaining amount, the lower the speed, and the higher the environmental temperature and the higher the ink remaining amount, the higher the speed. .

  Further, the intermittent connection between the first ink tank and the second ink tank is made between recording operations on the recording medium by the ink jet recording head.

  According to another invention, an ink jet recording head, a first ink tank having a small capacity for supplying ink to the ink jet recording head, and the first ink tank are intermittently connected to the first ink tank. Ink jet in a recording apparatus having a large-capacity second ink tank that supplies ink to the ink tank, and a suction mechanism that performs suction to fill the first ink tank from the second ink tank A method for recovering a recording head, wherein a detecting step for detecting a remaining amount of ink in the first ink tank, a time measuring step for measuring an elapsed time from a previous recording operation by the recording device, and a detection in the detecting step In order to recover the ink jet recording head according to the amount of ink remaining and the elapsed time measured in the timing step, A selection step of selecting one of a plurality of recovery operations having different amounts, and selecting an ink filling speed in the suction mechanism according to the selected recovery operation, the recovery operation selected in the selection step, and the ink And a recovery control step of performing recovery operation and driving and controlling the suction mechanism in accordance with the filling speed.

  Therefore, according to the present invention, according to the detected ink remaining amount and the elapsed time from the previous recording operation, one of a plurality of recovery operations with different ink filling amounts is selected for recovery of the ink jet recording head, Although the selected recovery operation is performed, the ink filling speed for ink filling is changed according to the selected recovery operation, so that it is possible to shorten the pre-recording operation related to the recovery operation. .

  This contributes to an improvement in recording throughput.

  Furthermore, even when the recovery operation includes preliminary ejection, the ink filling speed at the preliminary ejection is changed according to the detected remaining ink amount and the measured environment temperature, so that the pre-recording processing time for the recovery operation is shortened. And the reduction of ink consumption.

  Hereinafter, preferred embodiments of the present invention will be described more specifically and in detail with reference to the accompanying drawings.

  In this specification, “recording” (sometimes referred to as “printing”) is not only for forming significant information such as characters and figures, but also for human beings visually perceived regardless of significance. Regardless of whether or not it has been manifested, it also represents a case where an image, a pattern, a pattern, or the like is widely formed on a recording medium or the medium is processed.

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  Furthermore, “ink” (sometimes referred to as “liquid”) is to be interpreted broadly in the same way as the definition of “recording (printing)” above. It represents a liquid that can be used for forming a pattern or the like, processing a recording medium, or processing an ink (for example, solidification or insolubilization of a colorant in ink applied to the recording medium).

  Furthermore, unless otherwise specified, the “nozzle” collectively refers to an ejection port or a liquid channel communicating with the ejection port and an element that generates energy used for ink ejection.

  Furthermore, the recording head applicable to the present invention employs an ink jet recording method, and as a specific form thereof, film boiling occurs in the liquid using the thermal energy generated by the electrothermal transducer. Various forms such as a form for generating bubbles to form, a form for discharging liquid by an electromechanical transducer, and a form for forming and discharging liquid droplets using static electricity or air flow can be mentioned. Those using a converter are preferably used.

<Description of Inkjet Recording Apparatus (FIG. 1)>
1 and 2 are sectional views of an ink jet recording apparatus which is a typical embodiment of the present invention.

  As shown in FIG. 1, the carriage 40 integrated with the recording head ejects ink while reciprocatingly scanning in the arrow A direction. Here, the recording medium is conveyed in a direction substantially orthogonal to the direction of arrow A (in the drawing, from the back of the paper to the front). An ink tank 12 is mounted below the platen 9 that supports the recording medium. FIG. 1 shows a state where the ink tank 12 is lifted down so that the carriage 40 can be scanned.

  On the other hand, FIG. 2 is a view showing a state in which the ink tank 12 is lifted up by rotating around the fulcrum 7 as a rotation center.

  Here, the ink bags 86, 87, and 88 contain yellow (Y), magenta (M), and cyan (C) inks, respectively, and rubber plugs are inserted into these ink bags, respectively. A hollow ink supply needle is inserted into the rubber stopper. 2 is a side sectional view, a rubber plug 91 and an ink supply needle 94 for the ink bag 88 are shown, and those for the ink bags 86 and 87 are not shown. However, hereinafter, when referring to the rubber plugs and ink supply needles corresponding to the ink bags 86 and 87, they are referred to as rubber plugs 92 and 93 and ink supply needles 95 and 96, respectively.

  As can be seen from FIG. 2, only when ink supply is necessary, the ink bag in the ink tank 12 and the carriage 40 are connected to create an ink supplyable position.

  FIG. 3 is a cross-sectional view of the carriage at the ink supplyable position shown in FIG. 2 as seen from the carriage scanning direction.

  The air suction joint 48 shown in FIG. 3 is in contact with the carriage 40 to form an air suction path, and is connected to an air suction pump (not shown). A gas-liquid separation film 55 is provided above the sub-tanks 40b, 40c, 40d, and an air suction pump sucks air in the sub-tanks 40b, 40c, 40d through the air suction joint 48 and the gas-liquid separation film 55. The subtank in which each color ink is stored can be depressurized to supply the ink to the subtank. The sub tanks 40b, 40c, and 40d are filled with a negative pressure generating member such as a sponge, and a gas-liquid separation membrane is provided on the upper part thereof.

  Hereinafter, for convenience, the state in which the ink supply needle of the carriage is inserted into the ink tank as shown in FIG. 2 is referred to as “ink supplyable position”, and the state in which the air suction joint is in contact with the carriage as shown in FIG. It will be referred to as “a suckable state”.

  By using such an intermittent ink supply method, the sub-tanks 40b, 40c, and 40d above the recording head can be reduced in capacity with a simple configuration. Therefore, the carriage 40 itself can be made thinner, and the size and thickness can be reduced. An ink jet recording apparatus can be realized.

  Furthermore, since the waste ink absorber 23 shown in FIGS. 1 to 2 is contained in the ink tank 12, it is discarded simultaneously with the replacement of the ink tank 12. For this reason, it is not necessary to provide a large-capacity waste ink absorber in the main body of the recording apparatus, so that the apparatus can be further reduced in size and thickness.

  Further, in the above configuration, the rubber plugs 91, 92, 93 are provided on the ink tank 12 side which is a consumable, and the ink supply needles 94, 95, 96 penetrating the rubber are provided on the recording apparatus main body side. It is advantageous for the deterioration of the rubber plug by repeating the above. That is, since the rubber plug that has deteriorated due to repeated insertion and removal of the needle becomes a new one every time the ink tank 12 is replaced, it is not necessary to use a complicated configuration with excessive deterioration and an expensive rubber plug. Contributes to cost reduction.

  In the following description, the recording medium feeding, conveying and discharging, the image forming method by carriage scanning, and the removal and mounting of the ink tank are not directly related to the present invention, and these techniques are publicly known. Therefore, detailed description thereof is omitted.

  1-3 again, FIG. 1 also shows a state in which the carriage 40 is in a recordable position. The platen 9 and the ink tank 12 are in a position without lift-up, and the ink tank 12 is an arrow. It is loaded under the main platen from the B direction. In this state, after the recording medium is supplied, an image can be formed on the recording medium by repeating scanning of the carriage 40 in the arrow A direction. Then, after the recording on the recording medium is completed, an ink remaining amount detection mechanism (not shown) is used for recording between the next recording medium, that is, between successive recording media. When the amount of ink is estimated and it is determined that the amount of ink is small (for example, when the amount is less than the amount necessary for recording on one sheet of recording paper), the state of the recording apparatus is “ink” shown in FIG. Transition to “supplyable position”.

  The ink supply position is as described above. Further, as shown in FIG. 3, the suction joint 48 is brought into contact with the carriage 40 to form an air flow path, and the state of the recording apparatus is set to the “air suckable state”. .

  Here, the ink supply operation when the state of the recording apparatus shown in FIG. 3 is in the “ink supplyable position” and is in the “air suckable state” will be described.

  As shown in FIG. 3, the joint port 48a of the suction joint 48 comes into contact with the carrier 40, and an air flow path is formed from the suction port 40a to the sub tanks 40b, 40c, 40d. Thereafter, when the air in the sub tank is sucked out by an air suction pump (not shown), ink of each color is sucked out of the sub tank by the ink supply needles 94, 95, and 96 due to the negative pressure.

  Since each sub tank is provided with a gas-liquid separation film 55 for separating gas and liquid, when each sub tank is filled with ink, the ink comes into contact with the gas-liquid separation film, and all the inks are in this state. Then, since it becomes impossible to suck out air from the suction port 40a, the ink supply is automatically stopped. As for the negative pressure in the sub tanks 40b, 40c, 40d, a predetermined negative pressure is generated when ink is supplied, but when the ink supply is stopped, the negative pressure is canceled and the pressure returns to the atmospheric pressure.

  As shown in FIGS. 1 and 2, a protection / suction cap (hereinafter referred to as a suction cap) for protecting the recording head and sucking ink from the ejection port takes a mechanism that moves up and down simultaneously with lift-up. Yes.

  When the sub tanks 40b, 40c, and 40d are filled with ink in the ink supply operation described with reference to FIG. 3, the platen 9, the ink tank 12, and the suction cap 60 are set at intermediate positions between the lift-up position and the flat position. Is done.

  FIG. 4 is a cross-sectional view showing a state where the ink tank 12 is in the intermediate position.

  This intermediate position is a position where a recovery operation for removing bubbles remaining in the recording head 68 is performed. During the recovery operation, the suction cap 60 is kept sealed against the recording head 68 by the spring 63, but the ink supply needles 94, 95, and 96 are removed from the joint rubbers 91, 92, and 93.

  Since the recovery operation of the recording apparatus adopting the intermittent ink supply method has been proposed in detail in Japanese Patent Application No. 2003-272069, a detailed description thereof will be omitted. This is performed by sucking from the suction tube 67 in a state in which the atmosphere communication portion 66 is closed with capping. Ink is sucked in accordance with the negative pressure in the suction cap until the air communication portion is opened or until the negative pressure in the suction cap becomes almost zero. Further, at the same position, the state in which the atmosphere communicating portion 66 of the suction cap 60 is opened is set as the leaving position of the recording apparatus.

  Note that the recovery operation of the recording head includes maintaining a good ink discharge state by discharging ink that does not contribute to image recording from the recording head toward a suction cap, an ink receiving portion, or the like. Alternatively, the recovery performance and the ejection performance can be further stabilized by controlling the temperature of the recording head using a preheating means, but these are generally performed in conventional recording apparatuses. Since there is, further explanation is omitted.

  When the recovery operation is completed, the suction cap 60 is pulled away from the carriage 40 against the urging force of the spring 63, and the platen 9 and the ink tank 12 are returned to the same flat position that is not lifted up during the recording operation.

  In this state, that is, in the state shown in FIG. 1, after the carriage 40 is once moved to the right side, the wiper blade 106 is raised, and then the carriage 40 is moved leftward at a predetermined speed. Unnecessary ink adhering to the discharge port forming surface can be wiped off.

  FIG. 1 shows a state where the wiper blade 106 is set at the initial standby position and the recording head is ready for recording. In this state, the recording medium is supplied and the carriage 40 is reciprocated in the direction of arrow A shown in FIG. 1, while ink corresponding to the image data is ejected from the recording head 68 onto the paper to form an image.

<Control Configuration of Inkjet Recording Apparatus (FIG. 5)>
FIG. 5 is a block diagram showing a control configuration of the recording apparatus shown in FIGS.

  As shown in FIG. 5, the controller 600 includes an MPU 601, a program corresponding to a control sequence to be described later, a required table, a ROM 602 storing other fixed data, control of the carriage motor M1, control of the transport motor M2, and maintenance motor M3. Special purpose integrated circuit (ASIC) 603 for generating a control signal for controlling the recording head 68 and the recording head 68, a RAM 604, an MPU 601, an ASIC 603 provided with a development area for image data, a work area for program execution, and the like. A system bus 605 that connects the RAMs 604 to each other to exchange data, an analog signal from a sensor group described below is input, A / D converted, and an A / D converter 606 that supplies a digital signal to the MPU 601 Etc.

  In FIG. 5, reference numeral 610 denotes a computer (or a reader for image reading, a digital camera, or the like) serving as a supply source of image data, and is collectively referred to as a host device. Image data, commands, status signals, and the like are transmitted and received between the host device 610 and the recording device via an interface (I / F) 611.

  Reference numeral 620 denotes a switch group, which instructs to start a power switch 621, a print switch 622 for instructing the start of recording, and a process (recovery process) for maintaining the ink ejection performance of the recording head 3 in a good state. For example, a recovery switch 623 for receiving a command input from the operator. Reference numeral 630 denotes a sensor for detecting an apparatus state including a position sensor 631 such as a photocoupler for detecting a home position, a temperature sensor 632 provided at an appropriate position of the recording apparatus for detecting an environmental temperature, and the like. Is a group.

  Further, 640 is a carriage motor driver that drives a carriage motor M1 for reciprocating scanning of the carriage 40 in the direction of arrow A, 642 is a conveyance motor driver that drives a conveyance motor M2 for conveying a recording medium, and 644 is a maintenance motor M3. Is a maintenance motor driver for performing a recovery operation such as driving the air suction pump, operating the air suction pump, operating the wiper blade 106, and wiping the discharge port forming surface of the recording head.

  The ASIC 603 transfers drive data (DATA) of the printing element (ejection heater) to the printing head 68 while directly accessing the storage area of the RAM 602 during printing scanning by the printing head 68.

  Next, some examples of ink supply and recovery operations executed with the above-described configuration as a common configuration will be described.

<First embodiment>
FIG. 6 is a diagram schematically illustrating the outline of the ink supply operation according to this embodiment.

  FIG. 6 is a diagram for simplifying and simplifying FIG. 3, and the relative positional relationship between the suction joint 48 and the sub tank is different from that in FIG. 3.

  In FIG. 6, (a) shows a state in which the ink is consumed and the ink in the sub-tank becomes an intermediate amount. (B) is an “ink supplyable position” in which the ink tank is lifted up and the ink supply needle 94 is inserted into the rubber plug 91 to form an ink supply flow path, and the suction joint 48 is in the carriage 40. Shows an “air suckable state” in which an air suction flow path is formed in contact with. (C) shows that an air suction pump (not shown) sucks air in the sub-tank 40 through the suction joint 48 and the gas-liquid separation membrane 55 in the direction of the broken arrow to depressurize the sub-tank 40, and into the sub-tank. A state in which the ink is flowing as indicated by a dashed-dotted arrow is shown.

  Here, for comparison with the processing in this embodiment, (1) the ink filling control for protecting the meniscus, and (2) the intermittent ink supply method, the recording apparatus is employed. The recovery control for coping with the increase in the ink viscosity in the sub-tank due to the storage of the above will be described.

(1) Ink Fill Supply Control for Meniscus Protection FIG. 7 is a diagram showing a table used for controlling the pump speed during ink filling.

  First, sub tank capacity, pump capacity, and ink physical properties will be described. The sub tank in this embodiment can be filled with 0.5 cc of ink of each color. Therefore, in order to fill three colors of ink from empty to full, the pump needs to draw 1.5 cc of air. Actually, a larger pump capacity is required to shorten the ink filling time. In this embodiment, a pump capable of sucking 2.0 cc is used. As the ink, an ink having a viscosity of about 2.2 mPa · sec at 25 ° C., about 3.5 mPa · sec at 10 ° C., and about 4.5 mPa · sec at 5 ° C. is used. The surface tension is less dependent on temperature and is about 35 dyne / cm.

  In the above configuration, in this embodiment, the pump speed at the time of ink filling and supply is selected as shown in FIG. 7 according to the environmental temperature and the current amount of ink in the sub tank.

  Among the five pump speeds shown in FIG. 7, the pump speed 5 is 0.5 cc / sec at the maximum, that is, 2.0 cc of the pump stroke is sucked in 4 seconds. The pump speed 4 is 0.4 cc / second, and the entire stroke is sucked in 5 seconds. Hereinafter, the pump speed 3 is 0.3 cc / second, the suction time is about 6.7 seconds, and the pump speed 2 is 0.2 cc / second. The suction time is 10 seconds in seconds, the pump speed 1 is 0.133 cc / second at the lowest speed, and the suction time is 15 seconds.

  The environmental temperature is detected by a temperature sensor 632 using a diode provided on a substrate (not shown) of the recording apparatus main body. The temperature sensor 632 is preferably attached to a portion having a correlation with the temperature of the ink tank attached to the recording apparatus. In addition, the description regarding the technique regarding the accuracy improvement of temperature detection is abbreviate | omitted here.

  Further, the ink amount in the sub tank is obtained by counting the ink consumption (ink discharge amount and ink suction amount) since the previous ink filling. Here, the ink amount of the smallest color among the ink amounts of the three colors is used. Note that ink evaporation when the recording apparatus is left for a long period of time should be taken into consideration, but since a detailed description thereof is disclosed in Japanese Patent Application No. 2003-272069, it is omitted here.

  As shown in FIG. 7, in this embodiment, the pump speed is controlled in accordance with the environmental temperature and the amount of ink in the sub-tank, but this increases the ink viscosity and increases the flow resistance at low temperatures. Therefore, the inflow speed of the ink into the sub tank is slowed, and as a result, the negative pressure in the sub tank is increased and the meniscus of the nozzle is prevented from being destroyed.

  Also, when the amount of ink remaining in the sub-tank before ink filling is small and the amount of ink to be supplied is large, the negative pressure in the sub-tank is likely to rise similarly, so that the pump speed is reduced.

  In addition to the subtank capacity, pump capacity, and ink physical properties, the pump speed is determined by the meniscus of the nozzle in consideration of the initial volume of the air suction channel and the overall flow resistance of the ink supply system including the ink supply needle. The speed can be appropriately changed so as not to be destroyed.

  In this embodiment, by controlling the pump speed as described above, it is possible to supply ink filling without destroying the meniscus of the nozzle.

(2) About the recovery method of the nozzle of the recording head when the recording apparatus is left, if the system is a normal head tank on carriage, the ink corresponding to the evaporated amount is supplied from the ink tank even when the ink is not used. Therefore, the degree of ink concentration and viscosity increase is slight. However, when the intermittent ink supply method is adopted, the sub tank is separated from the main tank when the recording apparatus is not used. Therefore, when the volatile component of the small amount of ink in the sub tank evaporates, It becomes very concentrated and the viscosity increases, and it is necessary to execute special recovery control to recover this.

  FIG. 8 is a view showing a recovery sequence table suitable for the case where the intermittent ink supply method is used.

  In FIG. 8, the number of days left is the period during which the recording device is left unused, using an internal timer that is operated by a power source such as a coin battery (not shown) built in the recording device, The neglected time from the end of the previous recording is measured. The ink amount is the amount of ink in the sub-tank at the start of standing, that is, at the end of the previous recording, and is the ink amount of the smallest color among the three colors of ink. The ink amount calculation method is as described above.

  As shown in FIG. 8, the recovery sequence when the recording apparatus is operated next time is selected according to the leaving period and the ink amount at the start of the leaving. There are three types of recovery sequences: “small suction”, “first-step suction”, and “ink replacement”.

  FIG. 9 is a flowchart showing three types of recovery sequences that are generally performed.

  9A shows a small suction sequence, FIG. 9B shows a pre-sampling sequence, and FIG. 9C shows an ink replacement sequence.

  First, recovery by the small suction sequence will be described.

  According to FIG. 9A, first, in step S13, ink is filled to replenish ink for image formation, and then in step S14, a predetermined amount of ink is sucked to recover the nozzle, Next, wiping of the nozzle surface of the recording head is performed in step S15, and finally, in step S16, preliminary ejection for discharging ink mixed in the nozzle at the time of suction or wiping is performed. Thereafter, the process proceeds to image formation in step S40.

  The ink filling in step S13 fills the ink up to the gas-liquid separation film, and the ink suction amount at the time of suction recovery in step S14 is 0/10 of the sub tank capacity (0.5 cc). .05cc.

  As can be seen from FIG. 8, the small suction sequence is operated when the number of days left for a short period is short and the ink in the sub-tank has not evaporated much and the degree of increase in viscosity is small. Alternatively, even if the ink is left for a certain period of time, the amount of ink in the sub-tank before leaving is originally large, so that it is used even when it is expected that the ink concentration is not severe for evaporation.

  Next, the recovery by the advance suction sequence will be described.

  According to FIG. 9B, first, in step S22, suction for discharging the entire amount of ink in the sub-tank (this is called full suction) is performed. This is because the ink in the sub-tank evaporates to increase the viscosity and is concentrated, which is not suitable for the next image formation. Thereafter, similarly to the small suction sequence, ink filling in step S23, nozzle suction recovery in step S24, wiping in step S25, and preliminary ejection in step S26 are executed. Thereafter, the process proceeds to image formation in step S40.

  Here, the full suction is to discharge all the ink in the sub tank by continuously applying a negative pressure to the nozzle surface for a long time. Specifically, for example, the ink suction pump is operated so as to suck 2.0 cc, which is larger than the maximum ink amount in the sub tank, that is, the total of the three sub tank capacities (0.5 cc × 3). If a procedure that does not allow atmospheric communication for about 10 seconds is taken, negative pressure continues to be applied to the nozzle surface until atmospheric communication, and all the ink in the sub tank is discharged.

  Finally, recovery by the ink replacement sequence will be described.

  According to FIG. 9C, first, in step S31, fresh ink for washing the ink with very high viscosity in the vicinity of the nozzle is filled into the sub tank. Next, in step S32, the recording head is filled. A negative pressure is applied to the nozzle surface to perform the above-described all-out suction and discharge all the ink in the sub tank. At the same time, the ink having a high viscosity near the nozzle is washed away while being redissolved with fresh ink. Thereafter, in step S33, the sub tank is filled with ink for image formation. Thereafter, similarly to the small suction sequence and the pre-drawing suction sequence, the nozzle suction recovery is executed in step S34, the wiping is executed in step S35, and the preliminary discharge is executed in step S36. Thereafter, the process proceeds to image formation in step S40.

  As can be seen from FIG. 8, the ink replacement sequence is a case where the ink is left for a very long period of time, such as one year, and the ink volatile components in the sub-tank are almost evaporated to increase the ink viscosity. It is designed to work in severe cases. Further, even if the number of days to be left is about 100 days, when the ink is left in a state where only a small amount of ink is originally left in the sub-tank, the time for leaving is slightly short, the evaporation amount is at least slightly, and the increase in ink viscosity is severe. Since it is expected, an ink replacement sequence is executed.

  Further, as can be seen from FIG. 8, the pre-suction sequence is executed in the middle state between the small suction sequence and the ink replacement sequence.

Although the ink evaporation amount will not be described in detail, the inner diameter of the ink supply needle is made thin, the device for preventing evaporation from the sub tank itself is devised, the rubber thickness on the cap side or the tube material is improved, It is preferable to reduce as much as possible. In this embodiment, the evaporation amount is suppressed to about 1 mg / day for each color of ink under an environment of normal temperature and humidity.
As described above, when the (1) ink filling control for protecting the meniscus and (2) the intermittent ink supply method are employed, the ink viscosity in the sub tank is increased by leaving the recording apparatus. The recovery control to deal with was explained.

  In the process shown in FIG. 9, regardless of the type of sequence to be executed, ink filling (steps S13, S23, S31, and S33) is set according to the environmental temperature and the ink amount as shown in FIG. Control is performed so that the pump is driven at the determined pump speed.

  Next, ink supply and recovery operations according to this embodiment will be described.

  FIG. 10 is a diagram showing a table used for controlling the pump speed at the time of ink filling in this embodiment. In FIG. 10, the specific numerical values of the pump speed are the same as those described with reference to FIG. As can be seen from a comparison between FIG. 10 and FIG. 7, in this embodiment, the pump speed is not changed according to the change in the environmental temperature at the environmental temperature of 10 ° C. or higher.

  FIG. 11 is a flowchart showing three types of recovery sequences according to this embodiment.

  In FIG. 11, (a) shows a small suction sequence, (b) shows a leading-out sequence, and (c) shows an ink replacement sequence.

  In FIG. 11, the same steps as those already described in the flowchart of FIG. 9 are denoted by the same step reference numerals, and the description thereof will not be repeated.

  As can be seen from a comparison between FIG. 11 and FIG. 9, the table shown in FIG. 10 shows the ink filling control at the time of ink filling (steps S23, S31, S33) when the pre-suctioning sequence or the ink replacement sequence is selected. Used to determine

  In this way, in this embodiment, the ink filling method is optimized according to the type of the recovery sequence, and the time required for the pre-recording process is shortened.

  For example, when the pre-suction sequence is selected, since all the pre-suction is performed in step S22 before filling with ink in step S23, it is unnecessary time to control the pump speed for meniscus protection. Therefore, in this embodiment, with respect to ink filling after full suction that destroys such a meniscus, ink filling is performed with the pump speed fixed at the pump speed 3 at an ambient temperature of 10 ° C. or higher. I have to.

  In this case, according to FIG. 10, since all the ink in the sub-tank has been discharged, a minimum ink amount of less than 0.1 cc is selected for ink filling, and the pump speed 3 is It is selected. When the environmental temperature is lower than 10 ° C., the subtank may not be filled up. Therefore, the ink is charged over a period of time by reducing the pump speed by one rank from the normal temperature.

  Further, in the ink filling in step S31 of the ink replacement sequence, the meniscus is destroyed by the all-out suction in the next step S32. Therefore, it is not necessary to achieve the meniscus protection in step S31. Therefore, if the environmental temperature is normal temperature, as shown in FIG. 10, ink filling is performed in a short time using any one of pump speeds 3 to 5 in step S31 according to the ink amount in the sub tank. . In step S33, the ink filling time is shortened by using the pump speed 3 for the same reason as in step S23, and as a result, the pre-recording processing time is shortened.

  Thus, in this embodiment, by optimizing the control at the time of ink filling according to the type of the recovery sequence, the pre-processing time required for ink filling and recovery operation before recording can be shortened. The recording time is shortened.

  As the air suction pump (or ink suction pump) used in this embodiment, a tube pump can be used in addition to the syringe pump. The syringe pump is a classic one that controls a pump stroke and a pump speed in order to control a suction amount and a suction speed. The tube pump is characterized in that it can freely perform a suction operation using the driving time and speed as parameters. However, in order to ensure the quantitativeness of the suction amount, it is necessary to strictly control the driving time and speed. In this embodiment, the former syringe pump is used because it is relatively compact and the quantitative control is easy.

  Further, the gas-liquid separation film 55 used in this embodiment is a porous body, and the gas-liquid separation action is caused by a capillary force (meniscus force) generated by contact between fine holes and ink. In general, the smaller the hole diameter is, the more difficult it is to pass ink, but at the same time the air permeability (also referred to as Gurley number) deteriorates. At this time, the meniscus force increases and the breakdown voltage of the film also increases. In this embodiment, the gas-liquid separation film 55 is made of PTFE and has a pore size of 0.1 μm to 1 μm, a film thickness of 250 μm, and a pressure resistance of about 100 kPa. Used.

  In addition to this, any material having a gas-liquid separation function may be used, and various materials can be used depending on the type of ink and usage pattern. For example, in addition to a gas permeable film made of a resin porous material similar to tetrafluoroethylene resin, porcelain, ceramic earthenware, ceramic, or the like, or a similar porous material can also be used. Further, a valve having a mechanical configuration that opens when gas passes and closes when liquid tries to pass may be used as the gas permeable member.

  As disclosed in Patent Document 3, the ink supply performance is stabilized by filling the ink from the lower side of the ink containing member and reaching the gas-liquid separation film with a delay. In addition, a space is provided between the gas-liquid separation film and the ink containing member so that a space is formed immediately below the gas-liquid separation film as the ink is consumed from the recording head, and the time for contact with the ink is reduced, so that the next ink supply And the lifetime of the film can be improved.

  In order to prevent the negative pressure from being excessively applied to the gas-liquid separation membrane, the air suction pump is preferably provided with a pressure limiter such as an open valve (not shown).

  The air suction joint 48 for decompressing the air chamber and the sub tank is preferably made of silicon rubber or the like because it needs to be in close contact with the sub tank wall. The sub tank surface to be in close contact is also preferably flat, and the contact pressure may be set appropriately according to the material of the suction joint and the surface roughness of the sub tank surface.

  Further, the ink supply needle 94 is preferably a SUS pipe that is resistant to corrosion against ink, and has an outer diameter / diameter in view of damage to the rubber plug, evaporation from the ink supply needle when the recording apparatus is left, and flow resistance during ink supply. What is necessary is just to set an internal diameter. Of course, a hollow needle or a horizontal hole needle is not a problem.

  Furthermore, as the ink bag of this example, one side of an aluminum sheet was polypropylene coated, a sheet coated with polyethylene on one side was cut into 6 cm × 13 cm, folded with the PP side on the inside, and 3 sides bonded with a width of 5 mm Was used.

  Furthermore, although the rubber plug 91 of this embodiment is made of chlorinated butyl rubber, a rubber material can be selected according to the evaporation of ink in the ink bag and the insertion force of the ink needle at the time of lift-up.

  Furthermore, the sub tanks 40b, 40c, and 40d of this embodiment are filled with a negative pressure generating member for holding ink and generating a predetermined negative pressure. For example, an ink containing member such as a sponge is disposed in the sub tanks 40b, 40c, and 40d. As a material for forming the ink containing member, a high-density foam such as urethane, polypropylene, polyethylene, polytetrafluoroethylene, and cellulose can be used, and a negative pressure is generated by the capillary force of the foam.

  In general, the negative pressure generated by the ink containing member is desirably about −500 Pa or more in order to stabilize the ejection of ink in the recording head, and preferably the negative pressure is small until the ink is used up.

  Furthermore, as the molding material of the carriage 40, polysulfone is used here because of its good formability in processing and good wettability with respect to ink. However, since it is also a material of the sub tank, its thickness can be set in consideration of ink evaporation and gas permeability, or it can be covered with an evaporation suppression member as necessary.

  Furthermore, in this embodiment, a timer built in the recording device is used for the leaving time (number of days left), but based on time information acquired from a device such as a computer connected to the recording device, It is also possible to store the time at the end of recording in a memory in the recording apparatus and measure the standing time from the time when the recovery operation is performed. According to this configuration, it is not necessary to incorporate a timer in the recording apparatus, which contributes to cost reduction of the recording apparatus.

  Furthermore, in this embodiment, based on the ink remaining amount in the sub-tank at the end of recording, an appropriate pump speed and recovery sequence according to the ink state when performing the recovery operation in consideration of the environmental temperature and the leaving time However, in a recording device equipped with a configuration capable of detecting the ink remaining amount and ink density in the sub tank, the ink state is detected before the recovery operation is performed, and the ink state is A recovery operation may be performed. By doing so, it is possible to perform an appropriate recovery operation according to the ink state, and it is possible to reduce the amount of ink required for the recovery operation and to reduce ejection failures after the recovery operation is performed. Become.

  As described above, according to this embodiment, it is possible to shorten the processing time required for ink filling and recovery operation before recording by optimizing the control at the time of ink filling according to the type of the recovery sequence. Can contribute to improving throughput.

<Second embodiment>
In this embodiment, an example in which a preliminary ejection recovery sequence is provided as a recovery sequence in addition to the three types of recovery sequences described in the first embodiment will be described.

  The nozzles of the recording head are filled with ink after the previous image recording, but bubbles may be mixed into the nozzles depending on the leaving period (hereinafter, such bubbles are referred to as “leaving bubbles”). Therefore, before the next image recording, from the standpoint of leaving bubbles, it is preferable to perform ink filling and nozzle suction recovery as in the first embodiment. However, in the case where an image is frequently formed after being left for a short period of time, the suction recovery of the nozzle is also frequently performed. As a result, the ink consumption due to the ink discharge increases due to the suction, and the recording apparatus Increases operating costs.

  Therefore, in this embodiment, if left for a shorter period of time, there is less mixing of left bubbles, so that the nozzle is not recovered by suction but only by preliminary discharge.

  FIG. 12 is a flowchart showing the preliminary ejection recovery sequence.

  FIG. 13 is a diagram showing a recovery sequence table suitable for the case where the intermittent ink supply method according to this embodiment is used.

  As shown in FIG. 13, the preliminary ejection recovery sequence shown in FIG. 12 is used when the recording apparatus is left for a shorter period.

  When the leaving period is short, first, ink is filled in step S3. This ink filling control will be described in detail later.

  Next, in step S4, preliminary discharge is performed to recover the nozzle. The preliminary discharge amount may be merely discharging a small amount of ink in the vicinity of the nozzle, but the number of preliminary discharges may be increased to increase the discharge amount from the following viewpoint.

  At the end of ink filling in step S3, the ink is in a full state up to the gas-liquid separation film in the sub tank. At this time, as shown in FIG. 6C, ink filling is completed while the ink supply needle is also filled with ink. Therefore, the ink in the ink supply needle or the like is free ink that is not constrained by the sponge in the sub-tank, which may cause ink leakage from the needle and is not preferable. Therefore, for example, in the preliminary ejection recovery in step S4, the number of preliminary ejections may be increased so that the ink corresponding to the volume of the ink flow path from the ink supply needle to the sponge is discharged.

  Thereafter, the process proceeds to step S5, and wiping is executed. The wiping here is the same wiping as in steps S15, S25, and S35 already described. On the other hand, regarding the preliminary ejection in step S6 after wiping, the number of preliminary ejections may be significantly reduced from the number of preliminary ejections in steps S16, S26, and S36. This is because the preliminary ejection in steps S16, S26, and S36 is preliminary ejection after the suction recovery of the nozzle, and many other colors of ink are mixed in the nozzle, whereas during preliminary ejection in step S6, This is because only a slight color mixture occurs due to the ink adhering to the nozzle surface of the recording head being pushed into the nozzle by wiping in step S5.

  In this embodiment, the number of preliminary ejections at the time of preliminary ejection in step S4 is the number of preliminary ejections that consumes about 0.015 cc of ink for each color ink. In this embodiment, a recording head having 256 nozzles is assumed. Since the ejection amount of one drop of ink is 2 pl, each nozzle performs about 30,000 preliminary ejections. In the preliminary ejection after wiping in step S6, the number of preliminary ejections is 200.

  For reference, the number of preliminary ejections in steps S16, S26, and S36 described above is 30,000. The number of shots is set as the number of shots to the extent that color mixing after suction is eliminated.

  As described above, in this embodiment, the ink consumption can be reduced because it is not necessary to perform nozzle suction since the recording head is recovered only by preliminary ejection after being left for a short period of time.

  In this preliminary ejection recovery sequence, the ink filling control in step S3 is performed with reference to the table shown in FIG.

  FIG. 14 is a diagram showing a table used for controlling the pump speed during ink filling in the preliminary ejection recovery sequence.

  According to FIG. 14, after the pump speed is determined by the same method as described in FIG. 7, the suction speed is decreased to 1.5 times the speed and ink is slowly filled. Yes.

  In the preliminary ejection recovery sequence, it is most important not to destroy the meniscus of the nozzles of the recording head. This is because it is impossible to recover by the wiping in S5 and the preliminary ejection in Step S6, and ink recovery from the nozzles is necessary to recover.

  Therefore, in this embodiment, when the preliminary ejection recovery sequence is executed, as the ink filling in step S3, the pump speed is further reduced as compared with the first embodiment to improve the reliability of meniscus protection. Yes.

  As can be seen from FIG. 14, the pump speed is controlled by the environmental temperature and the ink amount in the sub-tank. In this embodiment, however, an environmental temperature detection accuracy error, an ink amount count error, and the like are taken into consideration. Even so, the pump speed is made slower so that the meniscus of the nozzle can be reliably protected.

  As described above, according to this embodiment, in addition to the first embodiment, a preliminary ejection recovery sequence is provided in order to cope with a case where the recording apparatus is left unused, and this sequence is included. Since the ink filling control required in accordance with the recovery operation in each recovery sequence is optimized, the reliability of the preliminary ejection recovery sequence can be improved in addition to the effects of the first embodiment.

  Even in the configuration described in the first embodiment, even if the meniscus of the nozzle may be broken at the time of ink filling in step S13 due to the above-described error, the degree is small, so in the next step S14. This can be recovered at the time of nozzle suction recovery. However, this nozzle suction recovery cannot be recovered if a large amount of air is mixed from the nozzle. In order to cope with this, when ink filling with high reliability related to meniscus protection as described in the second embodiment is applied to step S13 in the first embodiment, the ink filling and recovery operations before recording are always performed. It takes a long time, which is not preferable. Therefore, by changing the ink filling control according to the recovery operation as in the second embodiment, it is possible to achieve both the shortening of the pre-recording processing time and the reduction of the ink consumption. .

  Furthermore, in the above embodiments, the liquid droplets ejected from the recording head have been described as ink, and the liquid stored in the ink tank has been described as ink. However, the storage is limited to ink. It is not a thing. For example, a treatment liquid discharged to the recording medium may be accommodated in the ink tank in order to improve the fixability and water resistance of the recorded image or to improve the image quality.

  The above embodiment includes means (for example, an electrothermal converter or a laser beam) that generates thermal energy as energy used to perform ink ejection, particularly in the ink jet recording system, and the ink is generated by the thermal energy. By using a system that causes a change in the state of recording, it is possible to achieve higher recording density and higher definition.

  In the above embodiment, the serial scan type inkjet recording apparatus has been described as an example. However, the present invention is not limited to this, and inkjet recording using a full line recording head having the maximum width of a recordable recording medium. The present invention can be effectively applied to an apparatus. As such a recording head, either a configuration satisfying the length by a combination of a plurality of recording heads or a configuration as a single recording head formed integrally may be used.

  In addition, even the serial scan type as in the above-described embodiments is mounted on the recording head fixed to the apparatus main body or the apparatus main body so that the electrical connection with the apparatus main body and the ink from the apparatus main body The present invention is also effective when an exchangeable cartridge type recording head that can be supplied is used.

  In addition, the ink jet recording apparatus according to the present invention may be used as an image output apparatus for information processing equipment such as a computer, a copying apparatus combined with a reader, or a facsimile apparatus having a transmission / reception function. It may be one taken.

1 is a cross-sectional view of an ink jet recording apparatus that is a typical embodiment of the present invention. 1 is a cross-sectional view of an ink jet recording apparatus that is a typical embodiment of the present invention. FIG. 3 is a view of a cross section of a carriage at a position where ink can be supplied shown in FIG. 2 as viewed from the carriage scanning direction. FIG. 4 is a cross-sectional view showing a state where the ink tank 12 is at an intermediate position. FIG. 5 is a block diagram illustrating a control configuration of the recording apparatus illustrated in FIGS. 1 to 4. It is a figure which illustrates typically the outline | summary of the ink supply operation | movement according to a 1st Example. It is the figure which showed the table used in order to control the pump speed at the time of ink filling. It is the figure which showed the table of the recovery sequence suitable when the intermittent ink supply system is used. It is the flowchart which showed three types of recovery sequences generally performed. It is the figure which showed the table used in order to control the pump speed at the time of ink filling in a 1st Example. 3 is a flowchart showing three types of recovery sequences according to the first embodiment. It is a flowchart which shows the preliminary discharge recovery sequence according to a 2nd Example. It is the figure which showed the table | surface of the recovery sequence suitable when the intermittent ink supply system according to a 2nd Example is used. It is the figure which showed the table used in order to control the pump speed at the time of ink filling in a preliminary discharge recovery sequence.

Explanation of symbols

9 Platen 12 Ink tank 23 Waste ink absorber 40 Carriage 40b, 40c, 40d Sub tank 48 Suction joint 55 Gas-liquid separation film 55a Air chamber 60 Suction cap 63 Cap spring 86, 87, 88 Ink bag 91, 92, 93 Rubber plug 94 , 95, 96 Ink supply needle 106 Wiper

Claims (11)

A recording apparatus that performs recording using an inkjet recording head,
A small first ink tank for supplying ink to the inkjet recording head;
A large-capacity second ink tank that is intermittently connected to the first ink tank and supplies ink to the first ink tank;
Suction means for performing suction to fill the first ink tank from the second ink tank;
Detecting means for detecting the remaining amount of ink in the first ink tank;
Measuring means for measuring the environmental temperature of the recording device;
Time measuring means for measuring the elapsed time from the previous recording operation by the recording device;
According to the ink remaining amount detected by the detecting means and the elapsed time measured by the time measuring means, one of a plurality of recovery operations with different ink filling amounts is selected for recovery of the ink jet recording head. Recovery means for performing the selected recovery action;
And a suction control unit that controls the suction unit so as to change an ink filling speed by the suction unit in accordance with the selected recovery operation.   The recording apparatus according to claim 1, wherein the ink filling speed further changes in accordance with an ink remaining amount detected by the detection unit and an environmental temperature measured by the measurement unit. The ink jet recording head further includes preliminary ejection means for performing preliminary ejection of ink,
The recovery means selects one of the plurality of recovery operations including the preliminary discharge by the preliminary discharge means according to the ink remaining amount detected by the detection means and the elapsed time measured by the timing means. The recording apparatus according to claim 1, wherein a recovery operation of the inkjet recording head is performed.   When the recovery means selects preliminary ejection by the preliminary ejection means as the inkjet recovery operation, the suction control means includes the remaining ink amount detected by the detection means and the environmental temperature measured by the measurement means. The recording apparatus according to claim 3, wherein the suction unit is controlled to change an ink filling speed by the suction unit during the preliminary ejection. The suction means includes a suction pump;
After the first ink tank and the second ink tank are connected, the suction pump depressurizes the inside of the first ink tank, so that the second ink tank changes to the first ink tank. The recording apparatus according to claim 1, wherein the recording apparatus is filled with ink.   The plurality of recovery operations include a first recovery operation involving suction of a part of the first ink tank, a second recovery operation involving suction of the entire amount of ink in the first ink tank, and the first recovery operation. 6. The recording apparatus according to claim 1, further comprising: a third recovery operation that includes ink supply from two ink tanks and suction of the entire amount of ink in the first ink tank.   The ink filling speed is lower as the environmental temperature is lower and the remaining amount of ink is lower, and is higher as the environmental temperature is higher and the remaining amount of ink is higher. The recording apparatus according to claim 2, wherein the recording apparatus is a recording apparatus.   8. The intermittent connection between the first ink tank and the second ink tank is made between recording operations on the recording medium by the ink jet recording head. The recording device described in 1. An ink jet recording head, a small-capacity first ink tank for supplying ink to the ink jet recording head, and a large capacity for supplying ink to the first ink tank intermittently connected to the first ink tank A method for recovering an ink jet recording head in a recording apparatus, comprising: a second ink tank having a capacity; and a suction mechanism that performs suction to fill the first ink tank from the second ink tank. ,
A detecting step of detecting a remaining amount of ink in the first ink tank;
A time measuring step of measuring an elapsed time from a previous recording operation by the recording device;
According to the ink remaining amount detected in the detection step and the elapsed time measured in the timing step, one of a plurality of recovery operations with different ink filling amounts is selected for recovery of the ink jet recording head. A selection step of selecting an ink filling speed in the suction mechanism according to the selected recovery operation;
A recovery method for an ink jet recording head, comprising: a recovery operation selected in the selection step; and a recovery control step of driving and controlling the suction mechanism according to the ink filling speed. Further comprising a measuring step of measuring the environmental temperature of the recording device;
The ink jet recording head according to claim 9, wherein the selecting step further selects the ink filling speed according to a remaining ink amount detected in the detecting step and an environmental temperature measured in the measuring step. Recovery method. The recording apparatus has preliminary ejection means for causing the inkjet recording head to perform preliminary ejection of ink,
The selection step selects one of the plurality of recovery operations including preliminary ejection by the preliminary ejection means according to the remaining ink amount detected in the detection step and the elapsed time measured in the timing step. The method of recovering an ink jet recording head according to claim 9 or 10.

Images