JP2006110900A - Ink-jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink-jet recorder hardly causing the problem such as an ink leakage and poor delivery even if the recorder equipped with a valve mechanism changing the communication state of an ink feeding passage making a recording head and an ink tank communicated is arranged in the state of inclination. <P>SOLUTION: The ink feeding passage making the recording head and the ink tank communicated is composed with including a first liquid way 5c and a second liquid way 5d, and the passage is provided with a cut-off valve 10. The cut-off valve 10 makes the passage opened and closed by moving a diaphragm 10a upward and downward with a lever 11, and the lever 11 is composed of a horizontal member 11a and a perpendicular member 11b. The perpendicular member 11b is retained with a second rotary shaft 12 in freely pivoting, and the lower part side of the member 11b is always kept downward in the perpendicular direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording apparatus in which ink is supplied from an ink tank to a recording head through an ink supply flow path constituted by a tube or the like, and a valve mechanism is disposed on the ink supply flow path.

  Conventionally, as a general ink jet recording apparatus (also simply referred to as a recording apparatus), a carriage on which an ink jet recording head (also simply referred to as a recording head) is mounted, a conveying means for conveying a recording medium such as recording paper, and driving thereof And a serial type that performs recording while moving the carriage.

  In this type of recording apparatus, as a method for supplying ink to the recording head, a so-called “head tank integrated supply method” in which an ink tank for containing ink is integrated with the recording head, or an ink tank and a recording head are used. A so-called “tube supply system” connected by a tube, an ink tank and a recording head are provided separately, and if necessary, the recording head is moved to the position of the ink tank to connect them. A so-called “pit-in method” in which ink is supplied to a recording head is known. For the serial type recording apparatus, the “tube supply method” and the “pit-in method” are often adopted, and in particular, the “tube supply method” needs to stop the recording operation for ink supply. Has the advantage of not.

  FIG. 7 is a schematic diagram for explaining the configuration of a conventional ink jet recording apparatus disclosed in, for example, Patent Document 1. In FIG.

  The ink jet recording apparatus 250 shown in FIG. 7 is roughly divided into a recording head 201 for ejecting ink, an ink supply unit 205 for supplying ink to the recording head 201, and a recovery operation for the recording head 201. The recovery unit 207 is divided.

  The recording head 201 has a plurality of ejection nozzles 201g for ejecting ink on the lower surface thereof. The recording head 201 is also disposed at a relatively high position with a height difference with respect to the main tank 204, and is configured so that the inside of the recording head 201 is in a predetermined negative pressure state.

  The ink supply unit 205 includes an ink supply needle 205a for taking out ink from the main tank 204, and an air introduction needle 205b for introducing air into the main tank 204. As shown in FIG. Each tip of the needles 205 a and 205 b is configured to communicate with the inside of the main tank 204 in the mounted state.

  The lower end of the air introduction needle 205b is configured to communicate with the inside of a buffer chamber 205f disposed below the main tank 204. As a result, the inside of the main tank 204 and the inside of the buffer chamber 205f are in communication with each other via the atmosphere introduction needle 205b. A passage formed in an inverted U shape is provided on the other end side of the buffer chamber 205f, and a lower end portion of the passage serves as an air communication port 205g. The buffer chamber 205f configured in this manner temporarily stores ink when the ink overflows from the main tank 204 due to, for example, a change in external atmospheric pressure. Therefore, the buffer chamber 205f has an internal space of a predetermined size so that a predetermined amount of ink corresponding to the capacity of the main tank 204 can be stored. The height difference between the lower surface of the discharge nozzle 201g and the liquid level (water head surface) in the buffer chamber 205f is a water head difference, and the ink forms a meniscus on the discharge nozzle surface 201g. The height of the internal space of the buffer chamber 205f is such that the meniscus is optimized in the discharge nozzle 201g so that outside air does not enter the nozzle and ink leakage other than during discharge from the head does not occur. Is set as appropriate in consideration of the positional relationship between the buffer chamber 205f and the ink pressure difference based thereon.

  On the other hand, the lower end of the ink supply needle 205a is connected to an ink supply channel for transferring ink to the recording head 201a. A shutoff valve 210 for controlling the opening and closing of the flow path is disposed on the ink supply flow path. In the ink supply flow path, the downstream side (the recording head 201 side) of the shutoff valve 210 is constituted by a supply tube 206 having flexibility.

  The shutoff valve 210 is configured to be switched between an open state and a closed state by an inverted L-shaped lever 211 that is rotatably supported by a support shaft. A drive source for moving the lever 211 is a cam control motor 207 g provided as a component of the recovery unit 207. That is, the rotational power of the cam control motor 207g is converted into the horizontal movement of the link 207e via the second cam 207f, and the lever 211 is pushed up when the link 207e moves to the right side in the figure. The cam control motor 207g also serves as a drive source for the vertical movement of the suction cap 207a.

In the ink jet recording apparatus 250 configured in this way, during the recording operation, the suction cap 207a is retracted from the recording head 201, and the shutoff valve 210 is opened by the link 207e moving to the right side in the figure. It will be in the state. By doing so, both the ejection of ink from the recording head 201 and the ink supply from the main tank 4 to the recording head 1 can be performed.
Japanese Patent Application Laid-Open No. 2002-248777

  However, in the configuration of Patent Document 1 as described above, if the recording apparatus is disposed in an inclined state, the following problem may occur. That is, in the ink jet recording apparatus 250 of FIG. 7, the magnitude of the negative pressure at the lower end of the discharge nozzle 201g varies depending on the height of the gas-liquid interface of the ink stored in the buffer chamber 205f. Accordingly, the height dimension of the buffer chamber 205f is also set so that the magnitude of the negative pressure in the discharge nozzle 201f falls within a predetermined range. However, the setting of the height dimension is normally performed on the assumption that the recording apparatus 250 is arranged in a horizontal posture. When the horizontal posture of the recording apparatus 250 is maintained, it is possible to maintain a state in which a water head difference that is a difference between the lower surface of the discharge nozzle 201g and the liquid surface (water head surface) in the buffer chamber 205f is maintained. However, when the recording device 250 is disposed in an inclined state, the water head surface in the buffer chamber 205f changes, and as a result, the water head difference formed by the difference in height between the lower surface of the discharge nozzle 201g and the buffer chamber. Can not be maintained. In order to ensure the necessary water head difference, it is necessary to change the water head surface of the buffer chamber 205f, which may lead to a situation where the height of the buffer chamber is insufficient. As a result, the ink in the buffer chamber 205f may overflow from the atmosphere communication port 205g.

  For example, during a recording operation, that is, when the shutoff valve 210 is open and the recording head 201 and the main tank 204 are in communication, and a predetermined amount of ink has already been stored in the buffer chamber 205f. When the recording apparatus 250 is tilted, the water head difference collapses, so that external air flows into the sub tank from the discharge nozzle 201g side and leaks to the head side. As a result, the ink in the sub tank and the air that has flowed in flow into the main tank 204 through the supply tube 206 through the opened shutoff valve 210. Then, the ink in the main tank 204 is pushed out from the atmosphere introduction needle 205b, the ink flows backward into the buffer chamber 205f, and the ink overflows from the atmosphere communication port 205g. Once the ink overflows, the ink head surface becomes lower than the normal head surface height (corresponding to the lower ends of the needles 205a and 205b), and therefore overflows until all the ink in the main tank 204 is exhausted. Sometimes.

  In addition, the recording apparatus 250 is tilted, there is no ink in the recording head 201 or the supply tube 206, a predetermined amount of ink is stored only in the buffer chamber 205f, and the main tank 204 is attached to the needle portion. If the recording head 201 or the supply tube 206 is to be filled with ink when it is not in the state, when the new main tank 204 is attached to the needle portion, the recording device 250 is tilted. In some cases, the recording head 201 is positioned below the state of FIG. 7, and the recording head 201 is positioned above the state of FIG. At this time, since the ink is present only in the buffer chamber 205f and the main tank 204, when the ink tank 204 is attached, the liquid level of the supply needle 205a and the liquid level in the buffer chamber 205f are changed from the reference surface of the water head difference. Become. Since the apparatus is inclined, if the liquid level in the buffer chamber 205f is lower than the liquid level in 205a, the ink in the main tank 204 flows toward the buffer chamber 205f, and the atmosphere communication port 205g. A large amount of ink may overflow. It is possible to cope with the problem of ink overflow from the atmosphere communication port 205g by increasing the volume in the buffer chamber 205f. However, increasing the volume of the buffer chamber 205 in this way is possible. There is also a risk of increasing the size of the recording apparatus.

  As described above, taking the configuration of Patent Document 1 shown in FIG. 7 as an example, the problem when the recording apparatus is tilted has been described. However, the above-described problems caused by the tilting of the apparatus are as follows. It is believed that this can occur in other types of recording devices. Further, the problem in that case is not limited to the ink leakage as described above, and there is a possibility that, for example, ejection failure may occur due to the ink pressure in the recording head being out of the desired range.

  In any case, the cause of the above problem is that the valve mechanism is opened while the apparatus is tilted. Therefore, in order to prevent this, an appropriate valve mechanism is used according to the tilt of the recording apparatus. It is desirable to be able to control this.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a recording apparatus having a valve mechanism for switching a communication state of an ink supply flow path that connects a recording head and an ink tank, even if the recording apparatus is disposed at an inclination, ink leakage or ejection. An object of the present invention is to provide an ink jet recording apparatus which is unlikely to cause problems such as defects.

  In order to achieve the above object, an ink jet recording apparatus of the present invention is provided with an ink supply channel for supplying ink contained in an ink tank to a recording head for ejecting ink, and the ink supply channel provided in the ink supply channel. In an ink jet recording apparatus having a valve mechanism that opens and closes a flow path and a driving means that is a drive source for opening and closing the valve mechanism, the valve mechanism is freely rotated and displaced according to the inclination of the ink jet recording apparatus. It has a rotation member and is opened and closed through the rotation member.

  According to the ink jet recording apparatus of the present invention, by using a rotating member that is provided as an element constituting the valve mechanism and that freely rotates and displaces according to the inclination of the recording apparatus, the ink jet recording apparatus can respond to the inclination of the recording apparatus. Appropriate opening / closing control of the valve mechanism can be performed, and as a result, problems such as ink leakage and ejection failure are less likely to occur even when the recording apparatus is tilted.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram for explaining the basic principle of ink supply in an ink jet recording apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view schematically showing the configuration of the ink jet recording apparatus according to the embodiment of the present invention. FIG. 3 is a schematic diagram for explaining an ink supply channel for one color in the ink jet recording apparatus of FIG.

  The characteristic part of the present invention is mainly the shut-off valve and its peripheral structure, which will be described with reference to FIG. 4, and the other structural parts have the same or similar structure as a conventionally known ink jet recording apparatus.

  First, the basic principle of ink supply to the recording head 1 in the inkjet recording apparatus 50 of the present embodiment will be described with reference to FIG.

  As shown in FIG. 1, in the ink jet recording apparatus 50, the recording head 1 and the main tank 4 communicate with each other through the supply tube 6, and the flow path from the main tank 4 to each discharge nozzle 1 g of the recording head 1 is made of ink. be satisfied. The discharge nozzle 1g of the recording head 1 is disposed at a position higher than the liquid level of the ink accommodated in the main tank 4 by a height H, and the pressure in the recording head 1 is set to a negative pressure of the water head difference of the height H. It has been kept. A certain amount of ink is stored in the recording head 1.

  The discharge nozzle 1g of the recording head 1 is provided as a fine hole. Since the inside of the recording head 1 has a negative pressure as described above, the inside of the discharge nozzle 1g is also a negative pressure, and as a result, the ink in the nozzle is in a state where a meniscus is stretched on the nozzle tip side. Yes. As a result, it is possible to prevent ink from leaking from the discharge nozzle 1g and air from entering the discharge nozzle 1g from the atmosphere. The ink is ejected by pushing out the ink in the ejection nozzle 1g by the film boiling energy of a heater (not shown) disposed inside the ejection nozzle 1g. After the ink is discharged, a cycle in which the nozzle fills the ink again by the capillary force of the discharge nozzle 1g is repeated, and the ink is sucked up again from the main tank 4 to the recording head 1 through the supply tube 6.

  As shown in FIG. 2, the ink jet recording apparatus 50 performs reciprocal movement (main scanning) of the recording head 1 in the main scanning direction and conveyance (sub scanning) of the recording sheet S in the sub scanning direction for each predetermined pitch. A serial type that forms characters, symbols, images, and the like by repeatedly ejecting ink from a plurality of ejection nozzles 1g of the recording head 1 and adhering them to the recording sheet S while synchronizing with these movements. It is a recording device.

  The recording head 1 is detachably mounted on a carriage 2 that is slidably supported by two guide rails and is reciprocated along the guide rails by driving means such as a motor (not shown). The recording sheet S is opposed to the ink ejection surface of the recording head 1 by the conveyance roller 3 and crosses the moving direction of the carriage 2 so as to maintain a constant distance from the ink ejection surface (for example, It is conveyed in the direction of arrow A, which is a direction that goes straight. The nozzle row of the recording head 1 extends in a direction substantially orthogonal to the main scanning direction of the recording head 1. A plurality of independent main tanks 4 are configured to be detachably attached to the ink supply unit 5 in accordance with the color of ink ejected from the recording head 1. The ink supply unit 5 and the recording head 1 are connected by a plurality of supply tubes 6 corresponding to the respective ink colors, and the main tank 4 is attached to the ink supply unit 5 so that the ink is stored in the main tank 4. It is possible to independently supply the inks of the respective colors to the nozzle rows of the recording head 1.

  The recovery unit 7 faces the ink ejection surface of the recording head 1 in a non-recording area that is within the reciprocating movement range of the recording head 1 and outside the passing range of the recording sheet S. The ink supply unit 5 is disposed adjacent to the ink supply unit 5. The recovery unit 7 is a mechanism for forcibly sucking out ink or air in each nozzle from each ejection nozzle 1 g of the recording head 1 to perform cleaning of the ejection nozzle 1 g and ink filling operation to the recording head 1.

  As shown in FIG. 3, the inkjet recording apparatus 50 performs a recovery operation on the recording head 1 for ejecting ink, an ink supply unit 5 for supplying ink to the recording head 1, and the recording head 1. It is roughly divided into a recovery unit 7. Hereinafter, each configuration of the recording head 1, the ink supply unit 5, and the recovery unit 7 will be described in order.

  On the upper side of the recording head 1, there is provided a sub-tank portion 1b configured as an ink chamber for holding a certain amount of ink. A liquid chamber 1f that directly supplies ink to a plurality of discharge nozzles 1g arranged in parallel is formed below the sub tank portion 1b (the lower side in the drawing). A connector insertion port 1a to which the supply tube 6 is connected is provided on the side surface of the sub tank 1b. A partition 1e having an opening 1d is provided at the boundary between the sub tank 1b and the liquid chamber 1f, and the filter 1c is installed on the partition 1e. In this way, the sub tank 1b is connected to each discharge nozzle 1g via the filter 1c, the opening 1d, and the liquid chamber 1f. In the ink passage path inside the recording head 1, the ink supplied to the recording head 1 from the connector insertion opening 1a passes through the sub-tank portion 1b, the filter 1c, and the liquid chamber 1f to each discharge nozzle 1g. Supplied. Further, the space from the connector insertion port 1a to the discharge nozzle 1g is kept airtight with respect to the atmosphere.

  An opening is formed on the upper surface of the sub tank portion 1b, and this opening is covered with a dome-shaped elastic member 1h fixed to the upper surface of the recording head 1. The space (pressure adjusting chamber 1i) surrounded by the elastic member 1h communicates with the inside of the sub tank portion 1b through the opening, and the volume changes according to the pressure in the sub tank portion 1b. It has a function of adjusting the pressure in 1b.

  The discharge nozzle 1g has a fine cylindrical structure with a cross-sectional diameter of about 20 μm, and discharges ink from the discharge nozzle 1g by applying discharge energy to the ink in the discharge nozzle 1g. After discharging the ink, the discharge nozzle 1g The discharge nozzle 1g is filled with ink by the capillary force. Usually, for the purpose of high-speed image formation, this discharge operation is repeated at a cycle of 20 kHz or more. In order to give ejection energy to the ink in the ejection nozzle 1g, the recording head 1 has energy generating means for each ejection nozzle 1g. In the present embodiment, a heating resistance element that heats the ink in the ejection nozzle 1g is used as the energy generation means, and a command (drive signal) from a head control unit (not shown) that controls the drive of the recording head 1 is used. The heating resistance element is selectively driven to cause the ink in the desired ejection nozzle 1g to boil, and the ink is ejected from the ejection nozzle 1g using the pressure of bubbles generated thereby.

  As described above, the ink fills the discharge nozzle 1g in a state where a meniscus is formed. To achieve this, the inside of the recording head 1, particularly the discharge nozzle 1g, is maintained at a negative pressure. Yes. Here, if this negative pressure is too small, when foreign matter or ink adheres to the tip of the discharge nozzle 1g, the ink meniscus may collapse and the ink may leak out of the discharge nozzle 1g. On the other hand, if the negative pressure is too large, the force that pulls the ink back into the ejection nozzle 1g becomes stronger than the energy given to the ink during ejection, which causes ejection failure. Therefore, the negative pressure in the discharge nozzle 1g is preferably maintained in a certain range slightly lower than the atmospheric pressure. The range of the negative pressure varies depending on the number of discharge nozzles 1g, the cross-sectional area, the performance of the heating resistance element, and the like, but, for example, −40 mmAq (about −0.0040 atm = −4.053 kPa) to −200 mmAq (about −0.0. 0200 atm = −2.0265 kPa) (however, the specific gravity of ink≈the specific gravity of water is preferable).

  The filter 1c is for preventing foreign matter that clogs the discharge nozzle 1g from flowing into the liquid chamber 1f from the sub-tank portion 1b, and has a fine hole of 10 μm or less that is smaller than the cross-sectional width of the discharge nozzle 1g. It is comprised with the metal mesh which has. In the filter 1c, the ink contacts with only one surface of the filter 1c, so that an ink meniscus is formed in each fine hole by capillary force. Thereby, in the filter 1c, ink is easily transmitted, but air is not easily transmitted. Note that the smaller the micropore size, the stronger the meniscus, and the more difficult it is to pass air.

  A predetermined amount of air exists in the liquid chamber 1 f located downstream of the filter 1 c in the ink moving direction in the recording head 1. In other words, the liquid chamber 1f is not completely filled with ink, and an air layer exists between the ink in the liquid chamber 1f and the filter 1c. The amount of ink stored in the liquid chamber 1f is a minimum amount necessary to fill the discharge nozzle 1g with ink. If the air from the liquid chamber 1f enters the discharge nozzle 1g, ink may not be replenished to the discharge nozzle 1g after ink discharge, which may cause discharge failure. In particular, it is preferable that the ink is contained so that the discharge nozzle 1g is not exposed to the air in the liquid chamber 1f even when the entire recording apparatus 50 is tilted.

  The ink in the sub tank 1b is in contact with the upper surface of the filter 1c, and the area in contact with the ink is the effective area of the filter 1c. The pressure loss due to the filter 1c depends on the effective area of the filter 1c. The area of the filter 1c is set so that the pressure loss is less than the allowable value. The pressure loss increases as the mesh of the filter 1c becomes finer and the ink flow rate increases, and conversely, it is inversely proportional to the area of the filter 1c. In recent multi-nozzle and small dot printers, the pressure loss tends to be high, and the size of the filter is as large as about 10 × 20 mm, for example, the sub-tank portion upstream of the filter and the liquid chamber space downstream. Need. In this embodiment, the filter 1c is arranged so as to be horizontal in the usage state of the recording head 1c, and the ink is brought into contact with the entire upper surface of the filter 1c to maximize the effective area of the filter and reduce the pressure loss. .

  The pressure adjustment chamber 1i is a chamber whose volume decreases as the internal negative pressure increases. When the pressure adjustment chamber 1i is constituted by the elastic member 1h, a rubber material or the like is preferable as the elastic member 1h. Moreover, you may comprise by the combination of a plastic sheet and a spring other than the elastic member 1h. When the pressure adjusting chamber 1 i is not provided, the pressure in the sub tank 1 b directly receives resistance due to pressure loss when ink passes through the main tank 4, the ink supply unit 5, and the supply tube 6. Therefore, in the case of a so-called high duty that discharges ink at a high rate, such as discharging ink from all the discharge nozzles 1g, the pressure in the sub-tank portion 1b is applied to the supply tube 6, the ink supply unit 5, and the main tank 4. Since the ink is subjected to resistance due to pressure loss when the ink passes, the ink supplied to the recording head 1 is insufficient with respect to the ejected ink, and the negative pressure rapidly increases. If the negative pressure of the discharge nozzle 1g exceeds the aforementioned limit value of −200 mmAq (about −2.0265 kPa), the discharge becomes unstable, which is inconvenient in image formation. In the serial type recording apparatus, there is a state in which the ejection of ink is interrupted when the carriage 2 (see FIG. 2) is reversed after image formation with a high duty. In this case, the pressure adjustment chamber 1i plays a role like a capacitor by reducing the volume during ink discharge to relieve the increase in the negative pressure in the sub-tank portion 1b and restore at the time of inversion. As described above, the pressure adjustment chamber 1 i stabilizes ink ejection and suppresses the influence of pressure loss in the ink supply flow path from the main tank 4 to the recording head 1. For this reason, the supply tube 6 driven by the carriage 2 can also have a small diameter, which contributes to reducing the load of movement of the carriage 2.

  Although not shown in FIG. 2, on the side surface of the recording head 1, an electric board is connected to a contact (not shown) provided on the carriage 2 when the recording head 1 is mounted on the carriage 2. (Not shown) is attached. The electric board is formed with a plurality of terminals such as a terminal for supplying power from the recording apparatus main body and a terminal for exchanging signals between the recording apparatus main body and the recording head 1. Some of these terminals are short-circuited between the two terminals. If the contact corresponding to these terminals is open, the recording head 1 is not attached (“no head”). If it is closed, it is determined that the recording head 1 is mounted on the carriage 2 (“with head”). If it is determined that “there is a head”, then the power supply to the recording head 1 and the exchange of signals between the recording apparatus main body and the recording head 1 are started.

  Next, the ink supply unit 5 and the main tank 4 connected thereto will be described.

  The main tank 4 is configured to be detachable from the ink supply unit 5, and has two rubber plugs 4b and 4c attached to the lower part of a rigid case 4a. The main tank 4 is a sealed container by itself, and ink is stored in the main tank 4 as a liquid.

  The ink supply unit 5 has an ink supply needle 5 a for taking out ink from the main tank 4 and an air introduction needle 5 b for introducing air into the main tank 4. That is, the attachment portion of the main tank 4 is composed of the ink supply needle 5a and the air introduction needle 5b. The ink supply needle 5a and the air introduction needle 5b are both hollow needles, and are arranged with the needle points facing upward corresponding to the positions of the ink supply port and the air introduction port of the main tank 4. Is attached to the ink supply unit 5 so that the tip of the ink supply needle 5a and the tip of the air introduction needle 5b penetrate the rubber plugs 4b and 4c and enter the main tank 4, respectively. Thereby, the flow path in the main tank 4 and each needle can be communicated.

  The ink supply needle 5a is connected to the supply tube 6 through the first liquid path 5c, the shut-off valve 10, and the fifth liquid path 5d, and further communicates with the recording head 1. The “ink supply flow path” described in the claims corresponds to a flow path from the ink supply needle 5 a to the supply tube 6. The atmosphere introduction needle 5b communicates with the atmosphere via the liquid path 5e, the buffer chamber 5f, and the atmosphere communication port 5g. Also, the first liquid passage 5c at the lowest position among the ink supply passages from the ink supply needle 5a to the supply tube 6 and the highest passage among the passages from the air introduction needle 5b to the atmosphere communication port 5g. Both of the liquid passages 5e in the lower position are at the same height. For the ink supply needle 5a and the air introduction needle 5b, in order to suppress the flow resistance of the ink, for example, a relatively thick one having a diameter of about 1.6 mm is selected, and the ink flows at the tip of the needle. There is a lateral hole on the side of the needle, and ink flows through the needle through the needle hole. The diameter of the needle hole is preferably about 1 to 1.5 mm.

  The buffer chamber 5f connected to the atmosphere communication needle 5b is a space for temporarily holding ink flowing out from the main tank 4, and the lower end of the atmosphere introduction needle 5b and the bottom of the buffer chamber 5f have substantially the same height. It has become. The outflow of ink from the main tank 4 is caused when the air in the main tank 4 expands due to, for example, an increase in environmental temperature or a decrease in external air pressure.

  Thus, if the shutoff valve 10 is closed when the air in the main tank 4 expands, the ink in the main tank 4 is not supplied to the recording head 1 side, and the air introduction needle 5b and the liquid path It flows into the buffer chamber 5f through 5e. On the contrary, when the air in the main tank 4 contracts, the ink existing in the buffer chamber 5f is drawn into the main tank 4. Further, when ink is ejected from the recording head 1 in a state where the shutoff valve 10 is open and ink is present in the buffer chamber 5f, first, the ink in the buffer chamber 5f returns to the main tank 4 and is buffered. Air is introduced into the main tank 4 after the ink in the chamber 5f runs out.

  The volume Vb of the buffer chamber 5f having such a function may be set so as to satisfy the use environment (temperature environment) of the product. For example, if the product is intended to be used within a temperature range of 5 ° C. (278 K) to 35 ° C. (308 K), when the capacity of the main tank 4 is 100 ml, Vb = 100 × (308-278) / It may be set as 308 = 9.7 ml or more.

  Each of the ink supply needle 5a and the air introduction needle 5b is connected to a detection circuit 5h that measures the electrical resistance of the ink, thereby detecting the presence or absence of ink in the main tank 4. That is, the detection circuit 5h detects an electrical close because an electric current flows to the detection circuit 5h through the ink in the main tank 4 in a state where the ink is present in the main tank 4, and no ink is present. When the main tank 4 is not attached, an electrical open is detected. Since the detection current is weak, it is important to insulate between the ink supply needle 5a and the air introduction needle 5b. Therefore, the flow path from the ink supply needle 5a to the recording head 1 and the air introduction needle 5b are important. To the atmosphere communication port 5g is made completely independent so that the electrical resistance of only the ink in the main tank 4 can be measured.

  Next, the structure around the shutoff valve 10 will be described. As shown in FIG. 4C, the shut-off valve 10 has a diaphragm 10a made of a rubber material, and the first liquid path 5c and the second liquid path 5d are communicated by displacing the diaphragm 10a up and down. Done. A cylindrical spring holder 10b for holding a pressing spring 10c is attached to the upper surface of the diaphragm 10a, and the diaphragm 10a is pressed by the center of the diaphragm 10a by the pressing spring 10c to crush the diaphragm 10a. The opening surface of the fifth liquid passage 5d is closed by the lower surface of 10a. The spring holder 10b has a flange with which a lever 11 operated by a link 7e of the recovery unit 7 described later is engaged. By operating the lever 11 and lifting the spring holder 10b against the spring force of the pressing spring 10c, the first liquid path 5c and the second liquid path 5d communicate with each other.

  The shut-off valve 10 is opened when the recording head 1 is ejecting ink, is closed during standby or resting, and is further operated during the ink filling operation. Both the open / closed states are set while matching the timing.

  The configuration of the ink supply unit 5 as described above is provided for each main tank 4 except for the lever 11, that is, for each color ink of black, cyan, magenta, and yellow. The lever 11 is provided in common for all the main tanks 4, and one lever 11 is engaged with the spring holder 10 b of the shutoff valve 10 for each color. Thus, when the lever 11 is driven, the four shutoff valves 10 are controlled to open and close synchronously.

  In the ink supply unit 5 configured as described above, when the ink in the recording head 1 is consumed, the ink is supplied from the main tank 4 to the recording head 1 through the supply tube 6 at any time due to the negative pressure. . At the same time, the same amount of air as the ink supplied from the main tank 4 is introduced into the main tank 4 from the atmosphere communication port 5g through the buffer chamber 5f and the atmosphere introduction needle 5b.

  Next, the recovery unit 7 will be described. The recovery unit 7 has a function of sucking ink or air from the discharge nozzle 1 g and a function of opening and closing the shut-off valve 10. The recovery unit 7 includes a suction cap 7a serving as a cap unit for capping the ink ejection surface of the recording head 1 (a surface where the ejection nozzle 1g is opened), and a link 7e for operating the lever 11 of the shut-off valve 10. is doing.

  A tube is connected to the suction cap 7a, and a suction pump 7c is disposed at an intermediate position of the tube. The suction pump 7c is driven by a pump motor 7d. These suction cap 7a, tube, suction pump 7c, and pump motor 7d suck ink in the recording head 1 from the discharge nozzle 1g at a predetermined time. Is provided as a suction means.

  The suction cap 7a is made of an elastic member such as rubber at least in contact with the ink discharge surface, and also has a cap position that covers and seals the ink discharge surface, and a retreat position that is retracted away from the recording head 1. Are provided so as to be able to reciprocate between. The suction pump 7c is a tube type pump having a plurality of rollers, and can continuously suck ink by driving a pump motor 7d. Further, the suction amount can be changed according to the rotation amount of the pump motor 7d.

  The first cam 7b disposed so as to contact the lower surface of the suction cap 7a moves the suction cap 7a up and down between the two positions by rotating. A cam control 7g is provided in the drive source of the cam 7b. The link 7e is configured to be movable in the horizontal direction (the lateral direction in the figure), and FIG. A second cam 7f is in contact with the left end of the link 7e in the figure, and the second cam 7f is configured to rotate using the cam control motor 7g as a drive source. The first cam 7b and the second cam 7f are arranged on the same axis and are configured to rotate in synchronization.

  The first cam 7b has a part having a relatively small diameter and b and c parts having relatively large diameters. The second cam 7f has a and c portions with relatively large diameters and b portion with a relatively small diameter. The timing at which each of the parts a to c of the first cam 7b comes into contact with the suction cap 7a and the timing at which each of the parts a to c of the second cam 7f comes into contact with the link 7e coincide with each other. Has been.

In the state where the a part of each cam is in contact with the suction cap 7a or the link 7e, the suction cap 7a is positioned away from the ejection port surface of the recording head 1, and the link 7e is moved to the position for pressing the lever 11 (moved to the right side in the figure). Position). That Accordingly, as the lever 11 is described in FIG. 4 (c), and rotated in the arrow R ₁ upward about the rotary shaft 12a, the shut-off valve 10 is opened is pushed up. Further, in a state where the b portion of each cam is in contact, the suction cap 7a is moved upward, and the link 7e is moved to the left in the X direction in FIG. As a result, the ejection port surface of the recording head 1 is capped and the shutoff valve 10 is closed. In a state in which the c portion of each cam is in contact, the suction cap 7a keeps the position moved upward, and the link 7e takes the position where the lever 11 is pressed again. As a result, the shutoff valve 10 is opened while the discharge port surface of the recording head 1 is capped. In other words, in the present embodiment, the capping of the recording head 1 is released and the shut-off valve 10 is opened corresponding to the a part of each cam (referred to as “first state”), and the b of each cam. The recording head 1 is capped corresponding to the portion of the cam, and the recording valve 1 is capped and the shutoff valve 10 is closed (referred to as “second state”) and the c portion of each cam. At the same time, the shut-off valve 10 can be opened. These states are appropriately switched according to the operation state of the recording apparatus. For example, during the recording operation, the state is set to the “first state”, the shutoff valve 10 is opened, the ink is discharged from the discharge nozzle 1g, and the main tank. Ink supply from 4 is enabled. In the non-operating state including standby and rest, the recording head 1 is set to the “second state” to prevent the discharge nozzle 1g from being dried by capping the recording head 1, and the shutoff valve 10 is closed to remove the recording head 1 from the recording head 1. Prevent ink backflow.

  In the configuration of the present embodiment, the movement operation of the suction cap 7a and the movement operation of the link 7e are performed by the cam control motor 7g, which is a common drive source, so that the number of drive sources can be reduced. Is preferable. In addition, the moving direction of the suction cap 7a and the moving direction of the shut-off valve 10 are both in the vertical direction. Thus, matching the moving directions of the two members in this way is advantageous for sharing the drive source. is there. Further, since the first cam 7b and the second cam 7f are rotated by the cam control motor 7g on the same axis, the cam control motor 7g is rotated by a predetermined angle in one direction. With this simple control, a series of sequences of the suction cap 7a and the shutoff valve 10 can be executed. A control circuit (not shown) provided as a control means in the main body of the ink jet recording apparatus operates the entire recording apparatus, that is, the operation of the recording head 1, the movement of the carriage 2, the pump motor 7d and the cam control motor 7g. Also controls the drive of the.

  Next, the structure around the shutoff valve 10 which is a characteristic part of the present invention will be described in detail with reference to FIG. 4 is a diagram for explaining the structure around the shutoff valve in the recording apparatus of FIG. 3, and FIGS. 4A and 4B are perspective views showing the configuration and operation of the lever. (C) is an enlarged plan view showing an enlarged periphery of the shutoff valve.

  As shown in FIGS. 4A and 4B, the lever 11 includes a horizontal member 11a (pressing member) arranged to extend in the horizontal direction (X direction in the drawing), and a vertical direction perpendicular to the horizontal member 11a. It is comprised from the vertical member 11b (rotating member) extended in this. In FIG. 4A, a solid line indicates a normal state in which the lever 11 is not pressed by the link 7e, and a dotted line indicates a state in which the lever 11 is pressed and rotated by the link 7e.

Horizontal member 11a is disposed to extend in the X-Y plane direction in the figure, as the rotation around the rotation shaft 12a, one end thereof is rotatably supported in the direction of arrow R ₁ in FIG. One vertical member 11b is attached to the side surface of the horizontal member 11a on the side supported by the rotating shaft 12a, and is arranged extending in the ZY plane direction in the drawing. Upper side of the vertical member 11b is about the rotation shaft 12b, is supported rotatably in the arrow R ₂ direction.

By supporting the upper side of the vertical member 11b in this way, the lower side of the vertical member 11b is configured to always face downward in the vertical direction. If the recording apparatus is tilted, the vertical member 11b, as shown in FIG. 4 (b), rotationally displaced to the illustrated R ₂ direction rotation shaft 12b as the center of rotation. On the other hand, since the link 7e moves integrally with the recording apparatus, the vertical member 11b and the link 7e move relative to each other. In the state shown in FIG. 4B, the link 7e does not contact the vertical member 11b even if the link 7e is advanced. It will be. On the other hand, when the recording apparatus is arranged in a horizontal posture as shown in FIG. 4A, the link 7e can come into contact with the vertical member 11b. Therefore, when advancing the links 7e presses the vertical member 11b, the vertical members 11b and horizontal members 11a rotates displaced integrally with the illustrated R ₁ upward rotation shaft 12a as a rotation center. As a result, as shown by a dotted line in FIG. 4A, the tip end side of the horizontal member 11a moves upward, and thereby the spring holder 10b of the shutoff valve 10 is lifted.

In addition, the rotation locus | trajectory by the inclination of the apparatus of the vertical member 11b is settled in the vertical plane (ZY plane) orthogonal to the axial direction of the rotating shaft 12b. In such a configuration, when the inclination direction of the recording device 50 is a direction about the rotation shaft 12b (R ₂ direction of FIG. 4 (b)), it can be satisfactorily detect the inclination. Further, the axis direction of the rotating shaft 12b does not need to be strictly horizontal (for example, the X direction), and is slightly inclined with respect to the horizontal direction as long as the inclination of the apparatus can be detected by the vertical member 11b. May be. Even if the device is tilted, the mounting structure of the vertical member 11b is not particularly limited as long as the lower side of the vertical member 11b faces downward in the vertical direction.

  If the shutoff valve 10 including the lever 11 configured as described above is used, the ink as described in [Problems to be Solved by the Invention] even when the recording apparatus 50 is tilted. Leakage problems are less likely to occur.

That is, when placing the recording apparatus 50 in a horizontal position, since the vertical member 11b and the link 7e engages, the horizontal member 11a is pushed up in FIG R ₁ upward direction about the rotation axis 12a, resulting in blocking The valve 10 is opened. On the other hand, when the recording apparatus 50 is disposed at an inclination, the vertical member 11b and the link 7e are not engaged, the horizontal member 11a is not pushed up, and as a result, the shut-off valve 10 is kept closed. Thus, in the configuration of the present embodiment, since the opening and closing of the shutoff valve 10 is appropriately controlled according to the inclination of the recording device 50, the valve is opened while the device is inclined as described above. Therefore, problems such as ink leakage due to the occurrence of such problems are less likely to occur.

  In the above description, the shapes of the vertical member 11b and the link 7e are not particularly mentioned, but the vertical member 11b and the link 7e in FIG. 4 are specifically shown in cross section as shown in FIG. The shape is a rectangular member. However, these shapes can be variously changed, and for example, as shown in FIG. The link 17 shown in FIG. 5 (b) has a curved R portion 17a formed at the corner on the tip side. Similarly, the vertical member 21 has R portions 21 a formed on both sides of the surface facing the link 17. According to such a configuration, when the R portion of the link 17 and the R portion 21a of the vertical member 21 are in contact with each other, even if the link 17 is advanced, the vertical member 21 is around the rotation shaft 12b (see FIG. 4). ), The shut-off valve 10 cannot be opened. Therefore, the relationship between the inclination of the recording apparatus and the opening condition of the shut-off valve 10 can be more strictly defined. The R portions 21 a and 17 a that can obtain such advantages may be formed only on one side of the members 17 and 21.

  5 (c) and 5 (d) may be used. In these configurations, the portions where the link members 7e and 17 and the vertical members 11b and 21 are in contact with each other are rounded. Protrusions 7r, 11r, 17r, and 21r formed in different shapes are formed. Explaining the configuration of FIG. 5C as an example, the protrusions 7r and 11r are not in surface contact but in line contact (or point contact), and in this way, the area where two members come into contact with each other. If the device is set to be smaller, the contact between the two members will be lost if the device is tilted even slightly, and the condition for opening the shut-off valve can be defined more strictly.

  Furthermore, the lever that opens and closes the shut-off valve 10 and its peripheral structure may be as shown in FIG. In the configuration of FIG. 6, reference numeral 31 is a lever that opens the shut-off valve 10, and the lever 31 (pressing member) is integrally formed with a horizontal portion 31 a extending in the horizontal direction and a vertical portion 31 b extending in the vertical direction. At the same time, the lever 31 is configured to be rotatable around the rotation center axis 12c. A protrusion 30a that protrudes toward the link 7e is formed at the lower end of the vertical portion 31b. Between the lever 31 and the link 7e, a vertical member 20 (rotating member) configured to be rotatable around a rotation center axis 12d (see FIG. 6B) is disposed as a separate member. At the lower end of the vertical member 20, a protrusion 20 a that faces the protrusion 30 a is formed.

  The vertical member 20 is configured to be able to move in the moving direction of the link 7e, so that when the link 7e is advanced, the vertical member 20 also moves in synchronization and presses the lower end of the vertical portion 31b of the lever 31. It can be done. In the configuration of FIG. 6 provided as described above, the lower side of the vertical member 20 is always directed downward in the vertical direction (downward in the direction of gravity), and thus the inclination of the recording apparatus is detected in the same manner as in the configuration of FIG. be able to.

  As shown in FIG. 6C, a protrusion 20r as described with reference to FIGS. 5C and 5D may be provided on the side surface where the vertical member 20 contacts the link 7e. Similarly, the protruding portion 7r may be provided at a portion that contacts the vertical member 20 at the tip portion of the link member 7e.

It is a figure for demonstrating the basic principle of the ink supply in the inkjet recording device of one Embodiment of this invention. 1 is a perspective view schematically showing a configuration of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 3 is a schematic diagram for explaining an ink supply channel for one color in the ink jet recording apparatus of FIG. 2. 4A and 4B are diagrams for explaining the structure around the shutoff valve in the recording apparatus of FIG. 3, FIGS. 4A and 4B are perspective views showing the configuration and operation of the lever, and FIG. FIG. 4 is an enlarged plan view showing the periphery of a shutoff valve in an enlarged manner. It is a perspective view which shows the vertical member of FIG. 4, a link, and those modifications. It is a perspective view which shows the other example of the lever which opens and closes a cutoff valve, and its surrounding structure. It is the schematic for demonstrating the structure of the conventional inkjet recording device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording head 1g Discharge nozzle 4 Main tank 5 Ink supply unit 5c 1st liquid path 5d 2nd liquid path 5f Buffer chamber 6 Supply tube 7 Recovery unit 7b, 7f Cam 7e, 17 Link 7r, 11r, 17r, 20a, 20r, 21r Protrusion 10 Shut-off valve 10a Diaphragm 10b Spring holder 10c Pressing spring 11, 31 Lever 11a Horizontal member 11b, 20, 21 Vertical member (rotating member)
12a Rotating shaft 12b Rotating shaft 12c Rotating central shaft 12d Rotating central shaft 17a, 21a R section

Claims (9)

Ink supply flow path for supplying ink stored in an ink tank to a recording head for discharging ink, a valve mechanism provided in the ink supply flow path for opening and closing the flow path, and opening and closing operation of the valve mechanism In an inkjet recording apparatus having a driving means that is a driving source of
The ink jet recording apparatus, wherein the valve mechanism includes a rotating member that freely rotates and displaces according to an inclination of the ink jet recording apparatus, and is opened and closed through the rotating member.   The drive means includes a link member movably provided between a first position where the rotating member is pressed and a second position where the rotating member is not pressed. The inkjet recording apparatus according to claim 1, wherein the valve mechanism is opened when the link member is in the first position.   The inkjet recording apparatus according to claim 1, wherein the rotating member is provided with a rotation center axis on an upper side of the member and has a center of gravity on a lower side of the member.   The inkjet recording apparatus according to claim 3, wherein the rotation center axis is provided in a substantially horizontal direction.   5. The ink jet recording apparatus according to claim 2, wherein the rotating member has a curved portion in at least a part of a portion pressed by the link member.   The inkjet recording apparatus according to claim 2, wherein the link member has a curved portion in at least a part of a portion in contact with the rotating member.   The ink jet recording apparatus according to claim 2, wherein the driving unit further includes a cam for reciprocating the link member within a certain range.   The valve mechanism further includes a channel opening / closing member provided to be openable / closable to open / close the ink supply channel, and a pressing member for moving the channel opening / closing member, and the rotating member is the pressing member. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is attached to the ink jet recording apparatus.   The valve mechanism further includes a channel opening / closing member provided to be openable / closable to open / close the ink supply channel, and a pressing member for moving the channel opening / closing member, and the rotating member includes the pressing member The ink jet recording apparatus according to claim 2, wherein the ink jet recording apparatus is disposed between the pressing member and the link member in a state independent of the member.

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