JP2004181952A - Ink storage, inkjet head structure body having the same, and ink jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To raise an amount of filled ink and a usage efficiency of the ink when the initial filling of the ink to an ink container having an ink absorption member is carried out and the refilling of the ink is repeated. <P>SOLUTION: The ink absorption member 37 capable of absorbing and holding the ink is provided in a sub-tank 3 of an inkjet recording head 1, and a space V2 of a region in which the ink absorption member 37 is not placed, is formed by a first wall face 36a of the ink container 36 and the ink absorption member 37 in the sub-tank 3. A gas-liquid separation member 33 which is made of a porous member, allows a gas to pass therethrough and dose not allow a liquid such as an ink to pass therethrough, is provided to a cover member 35 having a ventilating hole 15. The volume of the space V2 and a total volume V1 of an amount of the ink ejected from an ejection nozzle of an inkjet recording element 38 in one time of a recovery operation and an amount of the ink ejected in the initial preliminary ejection are represented by the relationship of 0.7×V1≤V2≤V1. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an ink storage unit that stores ink to be replenished in a print head used in the ink jet printing field, an ink jet head structure including the ink storage unit, and an ink jet printing apparatus, and particularly to an ink jet recording head. An ink storage unit mounted on a carriage of the ink jet recording apparatus and preferably used in an ink jet recording apparatus employing an intermittent ink supply system which is connected to a main ink tank as necessary and receives intermittent ink replenishment. The present invention relates to an inkjet head structure and an inkjet recording device.

  As shown in FIG. 12, in an ink jet recording apparatus that performs recording while scanning an ink jet recording head, an ink jet recording head 201 having nozzles for discharging ink and an ink to be supplied to the head 201 are stored and held. A cartridge state in which an ink tank having an air communication portion that opens the inside to the atmosphere is connected to and detachable from the carriage (the recording head and the ink tank are inseparable from each other, A so-called on-carriage system is known, in which the carriage is mounted on a carriage and the carriage scans the head cartridge along a guide shaft 208 to perform recording.

  As shown in FIG. 13, only an ink jet recording head 301 is provided on a carriage 301a, a tank cartridge 301c containing ink is provided on the main body side, and a flexible ink cartridge is provided between the ink jet recording head 301 and the tank cartridge 301c. There is also a so-called tube supply type in which ink is supplied by connecting with a supply tube 301d.

  However, the on-carriage system as shown in FIG. 12, inevitably the weight becomes heavy because it has a head cartridge 201b for holding ink therein on a carriage 201a, or in some cases hinder fast scan carriage 201a Further, when the size of the head cartridge 201b is reduced in order to reduce the weight, the number of recordable images may decrease.

  On the other hand, in the tube supply system as shown in FIG. 13, since the ink cartridge 301c and the ink jet recording head 301 on the main body side are connected by the ink supply tube 301d, the mechanism becomes complicated and it may be difficult to reduce the size of the apparatus. Was.

  Therefore, a recording head having a sub-tank is provided on the carriage, and when necessary, the sub-tank on the carriage is connected to a main tank provided in the apparatus main body when the carriage is at a home position or a predetermined position. An intermittent ink supply method for supplying a predetermined amount of ink to a predetermined amount (hereinafter, also referred to as a pit-in method for convenience) has been proposed.

FIG. 14 shows a schematic diagram of an example of a pit-in type ink jet recording apparatus. (See Patent Document 1)
A recording head 401 that performs recording on recording paper 420 conveyed by a paper feed roller 421 is mounted on a carriage 401a. The carriage 401a is configured to be guided by a guide shaft 408. A main tank 404 for refilling the sub-tank of the recording head 401 with ink is arranged at the home position 423, and the main tank 404 is provided with a supply pipe 410 which is connected to the ink supply port 411 of the sub-tank 403. A dummy cap 406 for sealing and protecting the ink jet recording element, a suction cap 405 for sucking ink from a nozzle of the ink jet recording element, a negative pressure generator 407, and a suction cap for sucking air from a vent 415 of the sub tank 403. 422 is provided in communication with the negative pressure generator.

  Next, a pit-in operation in the pit-in type inkjet recording apparatus shown in FIG. 14 will be described.

  At the time of non-printing, the inkjet print head 401 is waiting at a home position 423 which is a position connectable to the suction cap 405, the suction cap 422, the dummy cap 406, and the main tank 404. When a print signal is sent to the main body of the printing apparatus, the dummy cap 406 seals a discharge port (not shown) of the ink jet print element, and the supply pipe 410 of the main tank 404 and the ink supply port 411 of the sub tank are connected. Then, the intake cap 422 is connected to the vent 415 of the sub tank 403, the negative pressure generator 407 is operated, and the pressure in the sub tank 403 is reduced, whereby ink is supplied from the main tank 404 to the sub tank 403.

  Next, a recovery operation is performed to prevent the ink in the nozzle from flowing backward to the sub tank 403 side when the pressure in the sub tank 403 is reduced, or to prevent a discharge failure caused by the thickened ink clogging the nozzle due to long-term storage. In this recovery operation, the ventilation port 415 and the ink supply port 411 of the sub tank 403 are opened, the suction cap 405 is connected to the ink jet recording element, and the ink in the nozzle is suctioned by the negative pressure generator 407. Further, after suction of the ink, wiping of the ink adhering to the ejection port surface of the ink jet recording head 401 (wiping) is performed, and then, preliminary discharge is performed to remove the mixed color ink pushed into the nozzle by the wiping, and then recording is started. .

  As described above, the pit-in method has only the ink jet recording element and the sub-tank 403 on the carriage 401a, so that the carriage 401a can be lightened, so that the ink jet recording head 401 can be scanned at high speed. Therefore, the number of recorded images can be increased. Further, since the carriage and the tank are not connected by the ink supply tube unlike the tank cartridge system, there is an advantage that the configuration of the apparatus is greatly simplified.

  As a mechanism for replenishing ink from the main tank to the sub-tank in the pit-in type ink jet recording apparatus, there is a method of detecting the amount of ink that can be supplied to the sub-tank at the time of pit in with a sensor and controlling the supply system for supplying ink (for example, And Patent Document 1).

  However, such mechanisms can be very complex, delicate and expensive.

  In order to solve this, a pit-in system in which a gas-liquid separation member is arranged in a sub tank has been proposed. FIG. 15 is a schematic view of a cross section of an example of an ink jet recording head used for a gas-liquid separation member type pit-in.

  This ink jet recording head is mounted on an ink jet recording apparatus as shown in FIG. An ink absorbing member 437 is arranged in an ink container 436 in which ink is stored, and a gas-liquid separating member 433 is arranged on a lid member 435 in the middle of communicating with a vent 415. The gas-liquid separation member 433 is a porous member made of PTFE (polytetrafluoroethylene) or the like that transmits gas but blocks liquid such as ink.

  Next, an ink replenishment operation for the pit-in type inkjet recording head shown in FIG. 15 will be described.

  When a recording signal is sent to the recording apparatus main body, the dummy cap 406 seals the ejection port of the ink jet recording element 438, and the supply pipe 410 of the main tank 404 and the ink supply port 411 of the sub tank are connected. Then, the suction cap 405 and the vent 415 of the sub-tank 403 are connected, and the negative pressure generator operates to discharge the air in the ink container 436 from the vent 415 through the gas-liquid separation member 433. Accordingly, the pressure in the sub tank 403 is reduced, and ink is supplied from the main tank 404 through the supply pipe 410 and the ink supply port 411 until the inside of the ink container is full. Immediately after the supply of the ink, as described with reference to FIG. 14, the recovery operation for preventing the ejection failure, the wiping operation, and the initial preliminary ejection are performed, and the recording material can be recorded.

  If the amount of intake air of the negative pressure generator 407 is equal to or larger than the inner volume of the sub-tank 403, the air in the ink container 436 is separated into air and liquid regardless of the state of the amount of ink remaining in the ink container 436. The ink is discharged through the member 433, and instead, the new ink is replenished. As described above, in order to fill the ink with ink, it is completed if a certain amount of air is sucked out.In principle, if a negative pressure generator is designed with a sufficient margin without having to perform air suction control. It is easily achievable.

As described above, in the pit-in type ink jet recording apparatus using the gas-liquid separation member, the ink can be easily and stably replenished. Also, if ink is replenished each time one sheet is printed, the usable ink capacity held in the sub tank will be the required amount of ink used for printing one sheet of recording paper, the amount of ink used for the recovery operation, and the preliminary ejection. It is necessary and sufficient if the total amount of ink used in the ink container is sufficient, and the ink container may be designed to be able to inject this amount of ink. Therefore, the size of the ink jet recording head can be reduced as compared with the conventional head cartridge type.
JP 08-112913 A

  As described above, in the pit-in type inkjet recording apparatus using the gas-liquid separation member, the head and the apparatus can be reduced in size as compared with the related art.

  However, in order to further reduce the size of the inkjet recording apparatus, there is a demand for further downsizing of the inkjet recording head, that is, downsizing of the sub tank.

  As a means of downsizing, it is conceivable to reduce the amount of ink mounted on the sub-tank. However, the amount of ink required for recording on the same recording material, the recovery operation for preventing ejection failure, and the ink required for preliminary ejection The amount is constant regardless of the device, and it is difficult to reduce the amount of ink. As another means for downsizing, there is a method of reducing the volume of the sub-tank by increasing the use efficiency of the ink filled in the sub-tank as much as possible.

  By the way, in the conventional ink jet recording head shown in FIG. 15, a porous ink absorbing member 437 is arranged over almost the entire ink containing portion. Thus, by using the capillary force of the porous body to keep the pressure of the ink acting on the ejection port negative, the amount of ink ejected from the ink jet recording head can be controlled well during recording, and the ink can be discharged from the ejection port during standing. Prevents ink leakage. On the other hand, since the ink absorber is disposed in the ink container, the ink filling amount is reduced by the volume of the ink absorbing member, and ink that is not used in the ink absorbing member after recording is generated, and ink is generated. There was a problem that the use efficiency was deteriorated (see FIG. 16A).

  Further, as a problem peculiar to the pit-in method in which recording and ink refilling are repeated, there is a phenomenon that an air pocket is formed in the ink absorbing member at the time of ink refilling, and the amount of ink filling decreases when recording and refilling are repeated. (See FIGS. 16B and 16C).

  In order to solve these problems, if an ink absorbing member is not provided in the ink container, a mechanism for generating a negative pressure in the ink container is required, which may increase the cost or increase the size of the structure depending on the structure. Invitation may occur.

  Accordingly, the present invention provides a smaller and less expensive ink storage unit having a large ink filling amount and high ink use efficiency even at the time of initial filling and repeated refilling, and a recording head structure including the ink storage unit. It is an object to provide a body and an ink jet recording apparatus.

  In order to achieve the above object, the ink storage section of the present invention is an inkjet head, an ink storage section configured to house an ink absorbing member that is attached to the inkjet head and stores ink to be refilled into the inkjet head, A decompression unit connected to the ink storage unit at a specific timing to decompress the inside of the ink storage unit; and a decompression unit connected to the ink storage unit at a specific timing and decompressed by the decompression unit to replenish the ink storage unit. An ink tank containing ink, and after ink is replenished to the ink storage unit using the pressure reducing means and the ink tank, a specific amount of ink is discharged from the inkjet head to perform an ink filling operation. An ink storage section of an ink jet recording apparatus, wherein an ink absorbing member is provided. And an ink absorbing member non-arranged area which is a space in which the ink absorbing member is not arranged and temporarily stores ink. Where V3 is the volume of V2, and V3 is the area in the ink storage portion where the ink is stored immediately after the ink is replenished, and V3 ≦ 20 · V1 and 0.7 · V1 ≦ V2 ≦ V1. .

  In addition, the ink jet head structure of the present invention includes an ink jet head, an ink storage unit configured to house an ink absorbing member attached to the ink jet head and storing ink to be refilled into the ink jet head, and an ink storage unit. And a decompression unit connected to the ink storage unit at a specific timing to reduce the pressure in the ink storage unit, and ink replenished to the ink storage unit by the decompression state by the decompression unit connected to the ink storage unit at a specific timing. An ink jet recording apparatus, comprising: an ink tank; and an ink filling operation by discharging a specific amount of ink from an ink jet head after the ink is replenished using a pressure reducing means and the ink tank with respect to an ink storage unit. An ink-jet head structure provided with an ink storage section, An ink absorbing member is disposed, and an ink absorbing member is not disposed, and has an absorbing member non-arranging region which is a space for temporarily storing ink without the ink absorbing member being provided. V3 ≦ 20 · V1 and 0.7 · V1 ≦ V2, where V1 is the amount of ink discharged, V2 is the volume of the non-absorbing member-arranged area, and V3 is the area in the ink storage section where ink is stored immediately after ink replenishment. It is characterized by having an ink storage section within a range of ≦ V1.

  Further, the inkjet recording apparatus of the present invention is an inkjet recording apparatus including a main tank for storing ink, a negative pressure generating device for generating a negative pressure, and an inkjet recording head having an ink discharge port for discharging ink. In addition, the ink jet recording head includes a sub-tank for storing the ink replenished from the main tank, and the sub-tank accommodates an ink absorbing member for holding the ink impregnated therein. A gas-liquid separation member for separating the air from the outside air is provided, and a ventilation port for discharging air in the sub-tank via the gas-liquid separation member and an ink filling section for refilling ink are provided. The generator is connected to the vent and discharges air from the sub-tank so that the sub-tank can be discharged from the main tank via the ink filling section. In an ink jet recording device that refills ink inside and discharges a specified amount of ink from the ink discharge port immediately after ink refilling, the area in the sub tank where ink is stored immediately after ink refilling An ink-absorbing member disposition region where the member is disposed, and an absorbing member non-disposition region which is a space where the ink absorbing member is not disposed and temporarily stores ink, and is a specified amount in ink discharge. When the amount is V1, the volume of the absorption member non-arranged area is V2, and the area in the sub tank where the ink is stored immediately after ink replenishment is V3, the range of V3 ≦ 20 · V1 and 0.7 · V1 ≦ V2 ≦ V1 It is characterized by being in.

  As described above, in the ink storage section, the inkjet head structure, and the inkjet recording head of the present invention, the area for storing the ink in the sub-tank has the absorption member arrangement area where the ink absorption member is arranged, and the ink absorption member is arranged. And an absorption member non-arranged region that is not provided. In other words, since the proportion of the ink absorbing member in the ink storing area is smaller than that in the configuration in which the entire ink storing area is occupied by the ink absorbing member, the ink absorbing member remains in the ink absorbing member without being used. The amount of ink can be reduced by the reduced amount of the ink absorbing member, and further, the reduced amount of the ink absorbing member also reduces the amount of air trapped in the ink absorbing member when refilling the ink. Therefore, the ink filling amount in the sub tank can be increased. Thus, the ink jet recording head of the present invention can increase the ink filling amount.

  Further, in the ink storage section, the inkjet head structure and the inkjet recording head of the present invention, the area in the sub-tank where the ink is stored immediately after the ink is replenished has an absorption member arrangement area where the ink absorption member is arranged, and an ink absorption area. An absorbing member non-arranged area which is a space where the member is not arranged and temporarily stores ink, the ink discharge amount which is a specified amount in ink discharging is V1, the volume of the absorbing member non-arranged area is V2, Assuming that the area in the sub-tank in which the ink is stored immediately after refilling the ink is V3, V3 ≦ 20 · V1 and 0.7 · V1 ≦ V2 ≦ V1 are satisfied. In this way, by providing an absorbing member non-arranged space equivalent to the amount of ink discharged in the ink discharging operation immediately after ink replenishment, so-called raw ink that is not impregnated and held in the ink absorbing member, Since the ink is quickly discharged by the ink discharging operation, an appropriate negative pressure is maintained for the ink discharge port when necessary, and there is no occurrence of discharge failure at the time of recording and ink leakage from the ink discharge port at the time of non-recording.

  As described above, according to the present invention, the area for storing ink in the sub tank has an absorbing member arrangement area where the ink absorbing member is arranged and an absorbing member non-arranging area where the ink absorbing member is not arranged. It has a configuration. In other words, the amount of ink remaining in the ink absorbing member that has not been used can be reduced by the amount of the ink absorbing member reduced, and the amount of ink absorbed by the ink absorbing member can be reduced when the ink is refilled. Also, the amount of air stagnation in the ink absorbing member can be reduced, so that the ink filling amount in the sub-tank can be increased, so that the usable ink amount can be increased without increasing the size of the sub-tank. . Also, the relationship between the total amount of ink V1 discharged from the discharge port in the ink discharging operation immediately after the ink filling, the volume V2 of the space without the ink absorbing member 37, and the volume V3 in the sub-tank in which the ink is stored immediately after refilling the ink. Are preferably V3 ≦ 20 · V1 and 0.7 · V1 ≦ V2 ≦ V1. As a result, the so-called raw ink that is not impregnated and held in the ink absorbing member is immediately discharged by the ink discharging operation immediately after the ink is filled. And no ink leakage from the ink ejection port during non-printing. Therefore, a smaller and more reliable inkjet recording apparatus can be provided at low cost.

Next, embodiments of the present invention will be described with reference to the drawings.
(1st Embodiment)
FIG. 1 is a partially schematic perspective view of a pit-in type ink jet recording apparatus of the present embodiment, and FIG. 2 is a gas-liquid separating member type ink jet recording head mounted on the ink jet recording apparatus shown in FIG. The side sectional view of each is shown.

  The ink jet recording apparatus according to the present embodiment replenishes a carriage 1a on which an ink jet recording head 1 for ejecting ink onto recording paper 20 conveyed by a paper feed roller 21 to perform recording and a sub tank 3 of the ink jet recording head 1. It has a main tank 4 for storing ink and a recovery mechanism 9 for recovering the ink ejection characteristics of the ink jet recording head 1.

  A carriage 1a on which the inkjet recording head 1 is mounted is guided by a guide shaft 8 and is reciprocally scanned in the direction of arrow A.

  The main tank 4 is arranged at a home position 23, and the main tank 4 is provided with a supply pipe 10 connected to the ink supply port 11 of the sub tank 3.

  The recovery mechanism unit 9 includes a dummy cap 6 for sealing and protecting the ink jet recording element 38, and a negative pressure generating device for sucking ink from the nozzle of the ink jet recording element 38 and sucking the ink from the vent 15 of the sub tank 3. And 7. The negative pressure generating device 7 comes into contact with the ink jet recording element 38 and sucks ink from the nozzles of the ink jet recording element 38, and the sub tank 3 comes into contact with the vent 15 provided in the sub tank 3. 3 is connected to a suction cap 22 for suctioning the inside.

  The ink jet recording head 1 includes a sub-tank 3 in which an ink absorbing member 37 for absorbing and storing ink is stored, a lid member 35 and a cover member 34 forming an upper surface of the sub-tank 3, and a lower surface of the sub-tank 3. And an ink jet recording element 38 for discharging ink supplied from the sub tank 3 to perform recording on the recording paper 20.

  The ink jet recording element 38 that performs recording by discharging ink onto the recording paper 20 has a common liquid chamber (not shown), a plurality of nozzles (not shown) communicating with the common liquid chamber, and discharge energy generated in these nozzles. It is generally constituted by a heater as a means. The ink supplied from the sub-tank 3 and in contact with each heater causes a state change accompanied by a steep volume change (generation of bubbles) due to the input of electric energy to each heater. Ink is ejected from an ejection port (not shown) communicating with each nozzle by force. Then, an image is formed on the recording material while being reciprocally scanned along the guide shaft 8.

  A lid member 35 and a cover member 34 are attached to the upper part of the sub tank 3. The lid member 35 is provided with a vent 15 on the lid side surface 35a and a communication portion 39 on the lid lower surface 35b side in order to communicate the inside of the sub tank 3 with the atmosphere. The gas-liquid separation member 33 is disposed on the lower surface 35b of the cover so as to close the communication portion 39. The gas-liquid separation member 33 is a porous member made of PTFE (polytetrafluoroethylene) or the like that transmits gas but blocks liquid such as ink. Are separated. That is, a communication path 40 to be described later and an area for storing ink in the sub tank 3 are spatially separated by the gas-liquid separation member 33.

  The cover member 34 is attached to the lid member 35 to form a communication path 40 connecting the ventilation port 15 and the communication portion 39.

  The area for storing the ink in the sub-tank 3 is formed between the area where the ink absorbing member 37 capable of impregnating and holding the ink is stored and the ink absorbing member 37 and the first side surface 36 a of the ink container 36. The ink absorbing member 37 is not provided, and has a space V2 in which so-called raw ink can be temporarily stored. The ink absorbing member 37 is made of a porous member such as polyurethane or polypropylene.

  In the present embodiment, the volume of the space V2 formed between the ink absorbing member 37 and the first side surface 36a of the ink container 36 is the amount of ink discharged from a discharge port (not shown) by a discharging operation immediately after ink replenishment. The amount is set to 0.021 cc, which is equivalent to the amount, and the capacity of the ink container filled with ink is set to 0.12 cc.

  Next, a recovery operation of the ink jet recording head in the ink jet recording apparatus of the present embodiment will be described with reference to FIGS.

  Before and immediately after the power of the printing apparatus main body is turned on, the ink jet print head 1 is waiting at the home position 23.

  When a recording signal is sent to the recording apparatus main body, the dummy cap 6 seals the ejection port of the ink jet recording element 38, and the supply pipe 10 of the main tank 4 and the ink supply port 11 of the sub tank 3 are connected. Then, the suction cap 22 is connected to the vent 15 of the sub-tank 3, the negative pressure generator 7 sucks a fixed amount of 0.15 cc, and discharges the air in the ink container 36 from the vent 15 through the gas-liquid separating member 33. . Accordingly, the pressure in the sub tank 3 is reduced, and ink is supplied from the main tank 4 into the ink container 36 through the supply pipe 10 and the ink supply port 11. Since the suction amount of the negative pressure generator 7 is larger than the ink container inner volume of 0.12 cc, the ink is filled up to the gas-liquid separating member 33 irrespective of the ink remaining amount in the ink container (FIG. 3). reference).

  Next, a recovery operation is performed to prevent the ink in the nozzle from flowing backward to the sub tank 3 side when the pressure in the sub tank 3 is reduced, or to prevent a discharge failure caused by the thickened ink clogging the nozzle due to long-term storage. This recovery operation is performed by keeping the ventilation port 15 and the ink supply port 11 of the sub tank 3 in an open state, connecting the suction cap 5 to the ink jet recording element 38, and operating the negative pressure generating device 7 by a fixed amount to cause the ink in the nozzle to move. Is sucked by V1a (= 0.02 cc) (see FIG. 4).

  Further, after the ink is sucked by a wiping device (not shown), the ink adhered to the ejection opening surface of the ink jet recording element 38 is wiped off by wiping. Then, in order to remove the mixed color ink pushed into the nozzles by the wiping, the ink is ejected by the preliminary ejection by an initial preliminary ejection amount V1b (= 0.001 cc) (see FIG. 5).

  After the above-described recovery operation and preliminary ejection are completed, the recording operation is started. At the start of recording, the so-called raw ink (raw ink portion 90 shown in FIG. 4) which is not absorbed by the ink absorbing member 37. Does not exist, an appropriate negative pressure can be generated. In addition, since a series of operations of the recovery operation and the preliminary ejection are immediately performed immediately after the ink is filled, the raw ink portion 90 that is not held by the ink absorbing member 37 exists for a very short time. No ink leakage occurs.

  Note that the numerical values used in the above description are V3 for the internal volume of the sub-tank in which ink is stored immediately after ink replenishment, V2 for the space without the ink absorbing member 37, and ink is discharged from the ejection port by one recovery operation. Assuming that the total volume of the amount V1a (= 0.02 cc) and the initial preliminary discharge amount V1b (= 0.001 cc) is V1, this is an example of the case of V2 = V1, V3 = 6 · V1, and is limited to this value. It is not done. It is sufficient that there is a space V2 having no ink absorbing member equal to or less than the total ink amount V1 discharged from the discharge port in a series of discharge operations performed immediately after ink filling.

  V2 = V1, V2 = 0.7V1, V2 = 0.5V1, V2 = 0 (conventional example) And the amount of usable ink (recovery ink + preliminary discharge ink + recording ink) was measured when recording and ink refilling were performed 2000 times. FIG. 6 shows the result.

  As can be seen from the graph, when the ink refilling is performed 2000 times, the improvement in the ink use efficiency with respect to the conventional example is about 0.008 cc increase (about 16% increase) when V2 = 0.5 · V1. On the other hand, when V2 = 0.7 · V1, it increases by 0.028 cc (about 56% increase), and when V2 = V1, it increases by 0.035 cc (about 70% increase) and V2 = 0. At 7.V1 or more, a remarkable increase in ink use efficiency was observed. This is a measurement result in which the volume of V2 is changed so that the relationship of V3 = 6 · V1 is obtained. When V3 is set to 20 · V1 and V3 = 25 · V1, and V2 is changed in the same manner as in the above test, That is, the same test was performed when the volume ratio of V3 to V2 was larger. At this time, each parameter, the ink usable amount after 2000 times of refilling of the ink, and the improvement ratio for V2 = 0 are shown in Table 1, and the improvement ratio for V2 = 0 is shown in a graph in FIG. As can be seen from FIG. 7, when V3 = 20 · V1, V2 / V1 ≧ 0.7, a remarkable increase in the ink use efficiency was observed, but when V3 = 20 · V1, V2 was maximized (V2 = V1). Even so, the increase was about 8%, indicating that the effect of the present case was extremely small. From the above results, the total amount of ink V1 discharged from the discharge port in the ink discharging operation immediately after the ink filling, the volume V2 of the space without the ink absorbing member 37, the sub-tank volume V3 in which the ink is stored immediately after the ink replenishment is obtained. Is preferably V3 ≦ 20 · V1 and 0.7 · V1 ≦ V2 ≦ V1.

  In the case of the present embodiment, as shown in FIG. 8, the proportion of the ink absorbing member 37 in the ink container 36 reduced due to the formation of the space V <b> 2, the ink absorbing member was arranged almost entirely over the ink container. Compared to an ink jet recording head (the conventional example shown in FIG. 8), the ink filling amount can be increased, and the remaining ink that is not used in the ink absorbing member after recording can be reduced. .

  Further, as shown in FIG. 9, the air pool at the time of refilling (in FIG. 9, the state where refilling has been performed 30 times) can be reduced.

  As described above, the configuration of the sub-tank in the ink jet recording head of the present embodiment can significantly improve the ink use efficiency for an ink jet recording head having a small ink capacity such as used in the pit-in system.

Further, since the ink use efficiency can be improved only by processing the ink absorbing member small under the above conditions, there is almost no increase in cost.
(Second embodiment)
FIGS. 10A to 10C are side sectional views of the ink jet recording head, each showing an example of an ink absorbing member applicable to the sub tank in the ink jet recording head of the present invention. In this embodiment, since the configuration of the ink jet recording head is the same as that shown in the first embodiment except for the shape of the ink absorbing member, the detailed description will be omitted. Also, the same constituent members will be described using the same reference numerals used in the first embodiment.

  The ink absorbing member 37a shown in FIG. 10A has an ink absorbing member such that a space V2 without the ink absorbing member is formed on the side of the second side surface 36b of the ink container 36 where the ink supply port 11 is provided. Has a shape in which the second side surface 36b side is obliquely cut.

  The ink absorbing member 37b shown in FIG. 10B has a configuration in which a space V2 without the ink absorbing member is formed at a corner of the ink container 36 defined by the first side surface 36a and the bottom surface 36c. Has a shape in which the lower right corner of the ink absorbing member is cut.

  The ink absorbing member 37c shown in FIG. 10C is formed such that a space V2 without the ink absorbing member is formed at a corner of the ink container 36 formed by the first side surface 36a and the gas-liquid separating member 33. 10 (c), the upper right corner of the ink absorbing member has a cut shape.

The shape of the ink absorbing member may be such that the space V2 arranged in the ink container may be a space closed by the ink absorbing member 37 and the inner wall of the ink container 36 as shown in the present embodiment. A space closed by the ink absorbing member 37 and the gas-liquid separating member 33 or a space closed by the ink absorbing member 37 and the inner wall of the ink container 36 and the gas-liquid separating member 33 may be used. However, the present invention is not limited to these, and any form can be selected as long as the ink absorbing member 37 is in contact with the communication port to the discharge port to generate a negative pressure at the discharge port.
Also in this example, the total ink amount V1 discharged from the discharge port in the ink discharging operation immediately after the ink filling, the volume V2 of the space without the ink absorbing member 37, and the sub-tank internal volume in which the ink is stored immediately after the ink refilling It is preferable that the relationship with V3 is V3 ≦ 20 · V1 and 0.7 · V1 ≦ V2 ≦ V1.
(Third embodiment)
FIG. 11 is a side sectional view of the ink jet recording head of this embodiment.

  In the sub tank 103 of the ink jet recording head 101 according to the present embodiment, the inside of the ink container 136 is divided into three ink chambers 106. An ink supply unit 103 is provided below each of the ink chambers 106, and supplies ink to the ink jet recording element 138 of the ink absorbing member 137 housed in each of the ink chambers 106.

  A lid member 135 and a cover member 134 are attached to an upper portion of the ink container 136. The lid member 135 is formed with a communication portion 107 corresponding to each ink chamber 116 and a vent 115 for communicating the inside of the ink chamber 116 with the atmosphere. The cover member 134 is attached to the lid member 135 to form a common communication path 117 that connects the ventilation port 115 and each communication portion 107.

  Each ink chamber 106 has an ink absorbing member 137 large enough to form a space V2 therein, and an ink supply port 111 communicating with the inside of the ink chamber 106 corresponds to each ink chamber 106. It is provided.

  The ink absorbing member 137 according to the present embodiment has a shape in which a space V2 without the ink absorbing member 137 is formed in a space closed by the inner wall of the ink container 136 and the gas-liquid separating member 133 as an example. However, the present invention is not limited to this, and the shapes shown in the first and second embodiments can be applied. The relationship between the total amount of ink V1 discharged from the discharge port in the ink discharge operation immediately after ink filling, the volume V2 of the space without the ink absorbing member 37, and the volume V3 of the sub-tank in which ink is stored immediately after ink refilling is shown. It is preferable that V3 ≦ 20 · V1 and 0.7 · V1 ≦ V2 ≦ V1.

  As described above, an example of the inkjet recording apparatus of the present invention has been described in detail, but the present invention is not limited to this, and a preferred configuration example will be described below.

  In the ink jet recording apparatus, the ink discharge amount V1 is set such that the ink discharged from the ink discharge port by the suction operation of the negative pressure generator, which is performed immediately after the ink is replenished, and the ink discharge amount is preliminarily discharged from the ink discharge port. The total amount of the ink and the ink may be used.

  In the ink jet recording apparatus, the area where the absorbing member is not disposed may be a space closed by the ink absorbing member and the inner wall of the sub tank.

  In the ink jet recording apparatus, the non-absorbing member-arranged region may be formed of a space closed by the ink absorbing member and the gas-liquid separating member.

  In the ink jet recording apparatus, the area where the absorbing member is not disposed may be a space closed by the ink absorbing member, the inner wall of the sub tank, and the gas-liquid separating member.

FIG. 1 is a partial schematic perspective view of a pit-in type ink jet recording apparatus of the present invention. FIG. 1 is a side sectional view of a gas-liquid separation member type inkjet recording head according to a first embodiment of the present invention. FIG. 3 is a side sectional view of the ink jet recording head shown in FIG. 2 in a state where the ink is fully filled. FIG. 3 is a side sectional view of the ink jet recording head shown in FIG. 2 in a state where a suction cap is connected to the ink jet recording element and ink is suctioned. FIG. 3 is a side sectional view of the ink jet recording head shown in FIG. 2 in which preliminary ejection is performed. 6 is a graph showing a change in usable ink amount with respect to the number of times of refilling of ink in Examples and Comparative Examples of the present invention. It is a graph which shows the ink available improvement rate with respect to V2 = 0. FIG. 2 is a schematic diagram comparing the ink filling amount at the time of initial filling and the usable ink amount in the ink jet recording head of the first embodiment of the present invention and a conventional example. FIG. 3 is a schematic diagram comparing the ink filling amount and the usable ink amount after 30 refills in the inkjet recording head of the first embodiment of the present invention and the conventional example. FIG. 7 is a side sectional view of a gas-liquid separation member type inkjet recording head according to a second embodiment of the present invention. FIG. 13 is a side sectional view of a gas-liquid separation member type inkjet recording head according to a third embodiment of the present invention. FIG. 3 is a partial schematic perspective view of an example of a conventional ink jet recording apparatus using a head cartridge system. FIG. 9 is a partial schematic perspective view of an example of a conventional ink jet recording apparatus using a tank cartridge system. It is a partial schematic perspective view of an example of a conventional ink jet recording apparatus using a pit-in system. FIG. 3 is a side sectional view of an example of a conventional pit-in type inkjet recording head. FIG. 9 is a schematic diagram schematically showing a change in usable ink amount due to refilling in a conventional pit-in type inkjet recording head.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1, 101 Ink-jet recording head 1a Carriage 3, 103 Sub-tank 4 Main tank 5 Suction cap 6 Dummy cap 7 Negative pressure generator 8 Guide shaft 9 Recovery mechanism part 10 Supply pipe 11, 111 Ink supply port 15 Vent port 20 Recording paper 21 Roller 22 Intake cap 23 Home position 33, 133 Gas-liquid separation member 34, 134 Cover member 35, 135 Cover member 36, 136 Ink container 36a First side surface 36b Second side surface 36c Bottom surface, 37, 37a, 37b, 37c, 137 Ink absorbing member 38 Ink jet recording element 39, 107 Communication section 40 Communication path 90 Raw ink section 106 Ink chamber 111 Ink supply port 115 Vent port 116 Ink chamber 117 Common communication path

Claims (5)

An ink-jet head, an ink storage unit provided with the ink-absorbing member that is attached to the ink-jet head and stores the ink to be replenished to the ink-jet head, and connected at a specific timing to the ink storage unit, A decompression means for decompressing the inside of the ink storage part, and an ink tank containing ink to be replenished to the ink storage part by the decompression state by the decompression means connected to the ink storage part at the specific timing. An ink jet recording apparatus that performs a ink filling operation by discharging a specific amount of ink from the ink jet head after ink replenishment is performed on the ink storage unit using the pressure reducing means and the ink tank. The ink storage unit,
An ink-absorbing member-arranged area in which the ink-absorbing member is arranged, and an absorbent-member-arranged area that is a space in which the ink-absorbing member is not arranged and temporarily stores ink, and has a specific amount in ink discharge Where V1 is the ink discharge amount, V2 is the volume of the absorbing member non-arranged area, and V3 is the area in the ink storage section in which ink is stored immediately after ink replenishment, where V3 ≦ 20 · V1 and 0.7 · V1. An ink storage unit, which is within the range of ≦ V2 ≦ V1. A connection portion of the decompression means and a storage region of the ink absorbing member are spatially separated by a gas-liquid separation member, and the filling of the ink into the ink storage portion is regulated by the gas-liquid separation member. Item 2. An ink reservoir according to Item 1. An ink-jet head, an ink storage unit configured to house an ink absorbing member attached to the ink-jet head and storing ink to be replenished to the ink-jet head, and the ink connected to the ink storage unit at a specific timing. A pressure reducing unit configured to reduce the pressure in the storage unit; and an ink tank connected to the ink storage unit at the specific timing and containing ink to be replenished to the ink storage unit by a reduced pressure state of the pressure reduction unit. An ink-jet recording apparatus for performing an ink filling operation by discharging a specific amount of ink from the ink-jet head after the ink is replenished using the pressure reducing means and the ink tank with respect to the ink storage unit; An inkjet head structure having an ink storage unit,
An absorption member arrangement region where an ink absorption member of the ink storage portion is arranged, and an absorption member non-arrangement region that is a space where the ink absorption member is not arranged and temporarily stores ink, V3 ≦ 20 · V1 where V1 is an ink discharge amount which is a specific amount in ink discharge, V2 is a volume of the area where the absorbing member is not disposed, and V3 is an area in the ink storage section in which ink is stored immediately after ink replenishment. An ink jet head structure provided with an ink storage section, wherein the ink flow rate is within a range of 0.7 · V1 ≦ V2 ≦ V1. The ink storage section spatially partitions a connection section of the decompression means and a storage area of the ink absorbing member by a gas-liquid separation member, and the ink-storage section is filled with ink by the gas-liquid separation member. An inkjet head structure provided with the ink storage section according to claim 3, which is regulated. An ink jet recording apparatus including a main tank that stores ink, a negative pressure generating device that generates a negative pressure, and an ink jet recording head having an ink ejection port that ejects ink, wherein the inkjet recording head is A sub-tank for storing ink replenished from the main tank is provided.In the sub-tank, an ink absorbing member for holding ink by impregnation is stored, and for separating ink stored in the sub-tank from outside air. A gas-liquid separating member is provided, comprising a vent for discharging air in the sub-tank via the gas-liquid separating member and an ink filling section for replenishing ink, the negative pressure generating device The sub-tank is connected to the air vent and discharges the air in the sub-tank from the main tank via an ink filling unit. Ink supplement is performed in the tank, in the ink jet recording apparatus for ink discharge of a specified amount from the ink discharge port immediately after the refilling of the ink is made,
An area in the sub-tank where ink is stored immediately after ink replenishment is an absorption member arrangement area where the ink absorption member is arranged and a space where the ink absorption member is not arranged and temporarily stores ink. V1 denotes the ink discharge amount which is a specified amount in the ink discharge, V2 denotes the volume of the non-absorber member-disposed region, and an area in the sub-tank where the ink is stored immediately after refilling the ink. Where V3 is within a range of V3 ≦ 20 · V1 and 0.7 · V1 ≦ V2 ≦ V1.

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