JP2008126449A - Liquid discharge apparatus, inkjet recorder and its recovery processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid as much as possible leakage and scattering of a liquid at a joining part etc., without a stand-by time being prepared by not smaller than necessary in a liquid suction discharge apparatus which sucks and holds a waste liquid if necessary in a waste liquid absorber that absorbs the waste liquid. <P>SOLUTION: According to a passed time after the discharge action last time and a discharge amount, a waste ink suction amount, and a timing or stroke speed of the drain action are changed. In other words, when the risk of overflow and scattering of the waste liquid is high, the timing or speed of draining the waste liquid is delayed. When the risk of overflow and scattering is low, the discharge action is controlled to complete more quickly. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid discharge device that discharges waste liquid intermittently to a waste liquid holding unit such as a waste ink tank of an ink jet recording apparatus. In particular, the present invention relates to a liquid discharging apparatus having a configuration in which the waste liquid holding means can be replaced.

  An ink jet recording apparatus forms an image by ejecting ink from a plurality of nozzles provided in a recording head in accordance with input image data and recording a plurality of dots on a recording medium. In such an ink jet recording apparatus, in a nozzle that is not frequently ejected, ink that has increased in viscosity due to evaporation of volatile components accumulates in the vicinity of the ejection port, or foreign matter such as dust is present in the ejection port that is open to the atmosphere. Or stick. The presence of such thickening ink or foreign matter affects the ejection state of the nozzle, causing non-ejection and deflection in the ejection direction. Therefore, in a general ink jet recording apparatus, a maintenance process (hereinafter also referred to as a recovery operation) for the recording head is performed periodically or as necessary in order to keep the ink ejection state appropriate.

  The maintenance process mainly includes a suction recovery process, a preliminary discharge process, a wiping process, and the like. In the suction recovery process, the face surface on which the discharge ports of the recording head are arranged is covered with a cap, and negative pressure is generated inside the cap by pump means such as a tube pump or piston pump, and ink is forced from each discharge port. This is a process of discharging. By performing the suction recovery process, it is possible to remove thickened ink and foreign matters that cause problems in the ejection operation from the inside of the head.

  The preliminary discharge process is a preliminary discharge operation for enabling stable discharge from each discharge port. The wiping process is a process of wiping off ink adhering to the face surface of the recording head with a suction recovery process, a preliminary ejection process, or a general recording operation using a wiping member or the like. In general, after the suction recovery process is executed, the preliminary discharge process and the wiping process are continuously performed.

  In an ink jet recording apparatus that performs such maintenance processing, waste ink holding means for collecting and holding waste ink generated by suction recovery processing and preliminary discharge processing is provided. If the recording apparatus is relatively large, a waste ink holding unit having a large capacity can be provided. However, an inkjet recording apparatus that has been miniaturized so as to be portable as in recent years cannot provide a waste ink holding unit that is too large, and the waste ink holding capacity is reduced due to the reduction of the waste ink holding unit. There are concerns.

  In order to cope with such a problem, an ink jet recording apparatus has been proposed in which the waste ink holding means can be attached and detached so that it can be replaced with a new one when the amount of waste ink stored reaches a predetermined amount. However, in the case of this configuration, it is an important issue to reliably suppress the leakage and scattering of the waste ink at the joint portion between the waste ink holding unit and the ink jet recording apparatus.

  Japanese Patent Application Laid-Open No. 2004-151867 absorbs waste ink while gripping the end of the waste ink tube at a portion of the waste ink holding means to which the end of the waste ink tube that transports waste ink from the recording apparatus main body is joined. A configuration in which members are provided is disclosed. With such a configuration, even if a certain amount of ink overflows at the joint, the overflowed ink is absorbed by the absorbing member, so that ink leakage and scattering at this portion are avoided.

JP-A-3-5159

  However, even in the case where the configuration disclosed in Patent Document 1 is adopted, there is a limit to the amount of the absorber that can be provided at the joint, and in a situation where ink overflows from the joint too frequently. As a result, ink leakage and flying are invited. Therefore, apart from the configuration described in Patent Document 1, a suction recovery operation is required so that ink overflow from the joining portion does not occur as much as possible.

  According to the study by the present inventors, the overflow of ink at the joint portion is caused by the flow rate of the waste ink transported from the recording apparatus toward the waste ink holding means and the absorber contained in the waste ink holding means. It occurs depending on the absorption rate. For example, if the next waste ink is discharged relatively soon after a large amount of waste ink is discharged, the waste ink tends to leak from the joint. This is because the next waste ink flows into the absorber provided inside the waste ink holding means before the previous waste ink penetrates sufficiently, so that the inflow speed of the waste ink exceeds the absorption speed of the absorber. This is because a special situation occurs. On the other hand, if sufficient time is taken between the discharge of the waste ink and the discharge of the second time, the penetration time into the waste ink holding means can be secured, so the inflow speed of the waste ink exceeds the absorption speed. However, even if the same amount of waste ink as described above is discharged, ink leakage does not occur.

Therefore, it is desirable to perform the suction recovery operation while always ensuring a sufficient standby time. However, since the length of the standby time affects the throughput of the printing apparatus, it is generally preferable to provide a sufficient standby time. It can not be said.
The present invention has been made in view of the above-described problems, and the object of the present invention is to avoid as much as possible the leakage or scattering of ink (liquid) at a joint or the like without providing a standby time longer than necessary. And a control method for a liquid suction / discharge device.

  Therefore, in the present invention, in the liquid discharge device that discharges the waste liquid intermittently to the waste liquid holding means provided with the absorber that absorbs the liquid, the liquid discharge device includes a means for acquiring the waste liquid discharge amount each time, and the previous waste liquid discharge amount Alternatively, at least one of the next waste liquid discharge timing or the discharge speed to the waste liquid holding means is made different according to at least one of the next waste liquid discharge amount.

  In addition, a recording head having a nozzle for ejecting ink, and a second piston opposite to the first direction that sucks ink from the nozzle by moving a piston disposed therein in the first direction. A cylinder pump for discharging the ink sucked by moving the piston in the direction of, a waste ink holding means having an absorber for absorbing the ink discharged from the cylinder pump, and the direction of the second direction in the second direction. An ink jet recording apparatus comprising: means for acquiring a discharge amount of ink discharged with one movement of a piston; and means for measuring an elapsed time from the previous discharge, wherein the elapsed time, the previous time In response to at least one of the discharge amount and the next discharge amount, the timing or discharge of the next ink discharge to the waste ink holding unit And wherein varying at least one of degree.

  Furthermore, by moving a piston disposed inside the cylinder pump in the first direction, the step of sucking ink from the nozzle that discharges ink according to the discharge data, and the second direction opposite to the first direction An ink jet recording apparatus comprising: a step of discharging the ink sucked by the suction step by moving the piston in a direction to a waste ink holding unit having an absorber; and a step of measuring an elapsed time from the discharge step And a timing for executing the next discharge step according to at least one of the elapsed time, the ink discharge amount in the previous discharge step, and the ink discharge amount in the next discharge step, or It is characterized in that at least one of the discharge speeds is made different.

  According to the present invention, when there is a strong concern about overflowing and scattering of ink, the timing of draining ink to the waste ink tank is delayed or the speed is reduced, and when there is little concern about overflowing and scattering, it is quicker. The drain operation can be controlled to be completed. As a result, it is possible to avoid leakage and scattering of ink as much as possible without providing standby time more than necessary.

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

  FIG. 1 is a diagram for explaining a schematic configuration of an ink jet recording apparatus applicable to the present invention. The recording head unit 1 is mounted on a carriage 2, and the carriage 2 is guided and supported so as to be capable of reciprocating along a guide shaft 3 extending in the main scanning direction. The carriage 2 is driven by a main scanning motor 4 through a transmission mechanism such as a motor pulley 5, a driven pulley 6, and a timing belt 7, and its position and movement are controlled. The carriage 2 is provided with a home position sensor 10 in the form of, for example, a transmissive photointerrupter, while the shielding plate 11 can shield the optical axis of the transmissive photointerrupter at a fixed portion of the printer corresponding to the home position of the carriage. Is arranged. Thus, when the carriage 2 moves and the home position sensor 10 passes the shielding plate 11, the home position of the carriage is detected, and the carriage position and movement can be controlled with reference to the home position.

  The driving force of the feeding motor 15 rotates the pickup roller 13 via a gear, whereby the recording medium 8 such as paper or plastic thin plate mounted on the auto sheet feeder (ASF) 14 is separated and fed one by one. Is done. Thereafter, the recording medium 8 is conveyed (sub-scanned) through the position (recording unit) facing the ejection port forming surface of the recording head unit 1 by the rotation of the conveying roller 9. The driving force of the conveying roller 9 is obtained from a line feed (LF) motor 16 via a gear.

  Judgment as to whether or not paper feeding has been performed and cueing at the time of paper feeding are performed based on the output of the paper end sensor 12 for detecting the presence / absence of the recording medium disposed on the upstream side of the recording position on the recording medium conveyance path. Is called. The paper end sensor 12 is also used for detecting the rear end of the recording medium 8 and determining the final recording position on the recording medium in the sub-scanning direction based on the detection output.

  Note that the back surface of the recording medium 8 is supported by a platen (not shown) so as to form a flat recording surface in the recording unit. In this case, the recording head unit 1 mounted on the carriage 2 is held so that its discharge port forming surface protrudes downward from the carriage 2 and is parallel to the recording medium 8.

  Reference numeral 210 denotes a cap for sucking ink from the recording head unit 1 and protecting the ejection port forming surface of the recording head. The cap 210 is connected to a syringe pump or the like (not shown in FIG. 1), and performs a recovery process of the recording head. Reference numeral 106 denotes an ink supply port to the recording head unit 1. The ink jet recording apparatus according to the present embodiment employs a so-called pit-in method in which ink is supplied from the ink tank 110 fixed to the main body to the recording head unit 1 as necessary, instead of mounting the ink tank on the carriage. . The ink supply port 106 provided in the recording head unit 1 and the rubber plug 112 attached to the inlet of the ink tank 110 are combined, so that an appropriate amount of ink stored in the ink tank 110 is sent to the recording head unit 1. It is. Contact of the cap 210 to the ejection port surface and joining of the ink supply port 106 and the rubber plug 112 can be performed with the carriage 2 positioned at the home position.

  FIG. 2 is a block diagram for explaining a control configuration in the ink jet recording apparatus of the present embodiment. Reference numeral 400 denotes a controller that controls the entire apparatus by acquiring information from each mechanism in the apparatus and transmitting a command. In addition to the CPU 401, the controller 400 includes a ROM 402 that stores various programs and a RAM 403 that is used as a work area for the CPU 401. In addition to the above programs, the ROM 402 stores tables and fixed data necessary for various controls, and stores a threshold value for a recovery sequence and a standby time for realizing the present invention.

  A host device 404 connected to the outside of the recording apparatus is a supply source of image data. Image data, other commands, status signals, and the like are transmitted / received to / from the controller 400 via the interface (I / F) 405.

  The head driver 406 drives an electrothermal transducer (discharge heater) provided in each nozzle of the recording head 100 according to the discharge data. The recording head 100 of the present embodiment has a mechanism in which a voltage pulse is applied to the electrothermal transducer to cause film boiling in the ink in the nozzle, and the ink is ejected as droplets by the generated bubble energy. It has become. In addition to the ejection for recording, the above-described preliminary ejection is performed by such a mechanism. However, such a discharge method does not limit the present embodiment. Whatever ejection method is employed, any configuration that can eject ink from individual nozzles provided in the recording head 100 in accordance with the ejection signal can be applied to the present embodiment.

  The main scanning motor driver 407 is a driver for driving the main scanning motor 4, and the line feed motor driver 408 is a driver for driving the line feed motor 16.

  A pump motor driver 409 is a motor for driving a pump motor 410 serving as a drive source for various mechanisms in the ink supply system and recovery system of the present embodiment. Further, the suction timer 412 is a timer for measuring an elapsed time after the pump motor 410 performs a suction operation on the recording head 100. The CPU 401 compares the elapsed time obtained from the suction timer 412 with various threshold values stored in the ROM 402, and controls various recovery system mechanisms including the pump motor 410 according to the comparison result.

  FIG. 3 is a schematic diagram for explaining an ink supply system and a recovery system mechanism in the present embodiment. Here, the carriage 2 is located at the home position, and the cap 210 can contact the recording head unit 1 and the pit-in cap 261 can be joined to the pit-in port 105.

  Reference numeral 100 denotes a recording head that serves as an ink discharge portion of the recording head unit 1 and has a nozzle port surface 101 on which a plurality of ink discharge ports (nozzle ports) are formed.

  The recording head 100 of this embodiment has a pit-in chamber 107 therein, and the pit-in chamber 107 is divided into two chambers by a gas-liquid separation film 108 as shown in the figure. The lower chamber serves as a reserve tank 104 for storing ink stored from the ink tank 110, and stores an ink absorbing member 103 for holding ink. The ink supply port 106 provided on the reserve tank 104 side has a pit-in needle 102 provided at the tip thereof. On the other hand, a pit-in port 105 serving as an opening is also provided on the gas chamber side of the pit-in chamber 107 of the recording head unit 1, and the pit-in port 105 can be connected to a cylinder pump 230 described later.

  The ink tank 110 according to the present embodiment is configured to be detachable from the ink jet recording apparatus, and includes an ink bag 111 containing ink therein. The ink tank 110 is controlled to move in the vertical direction (J direction or K direction) in the figure, and the pit-in needle 102 of the recording head unit 1 punctures a rubber plug 112 provided in the ink tank 110 while moving in the J direction. . As a result, the inside of the ink bag 111 containing ink and the reserve tank 104 in the recording head unit 1 are connected.

  The cap 210 is generally made of an elastic material such as rubber in order to ensure adhesion with the nozzle mouth surface 101, and an ink absorber 215 made of a porous material or the like is provided inside the cap 210. Yes. The cap 210 is controlled to move up and down in the direction of arrow C in the figure, the upper position is a capping position for sealing the nozzle mouth surface 101, and the lower position is an open position. Connected to the cap 210 are an atmosphere communication tube 250 for communicating with the atmosphere and a suction tube 220 for discharging waste ink. The atmosphere communication tube 250 is provided with an atmosphere communication valve 251 for controlling the atmosphere communication in the cap 210. On the other hand, the suction tube 220 is connected to a cylinder pump 230 as suction / discharge means, and a check valve 221 is provided in the middle of the path so that ink is transported only in the arrow Q direction (cylinder pump direction). Is provided.

  A piston 231 provided with a piston shaft 232 is installed in the cylinder pump 230, and the piston shaft 232 can be reciprocated by forward / reverse rotation driving of the pump motor 410 via a gear train, a lead screw, or the like. ing. As the piston shaft 232 moves, the piston 231 also moves in the cylinder in the direction of arrow S or D, and the space on both sides of the piston in the cylinder pump 230 is pressurized or depressurized by this operation. In the ink jet recording apparatus of this embodiment, such pressurization / decompression is used to suck ink from the nozzle opening or supply new ink to the recording head 1.

  The cylinder pump 230 has a drain (discharge) tube 240 for further transporting waste ink stored in the cylinder pump 230 to the waste ink tank 300 and a pit-in tube 260 for circulating air between the pit-in chamber 107. Is connected. The drain tube 240 is provided with a check valve 241 so that ink is transported only in one direction, that is, in the arrow H direction. On the other hand, a pit-in cap 261 made of an elastic material such as rubber for connecting to the pit-in port 105 of the pit-in chamber 107 is provided at the tip of the pit-in tube 260. The pit-in cap 261 is controlled to be movable in the T direction or the P direction in the figure.

  The waste ink tank 300 includes a waste ink absorber 310 made of a porous material or the like, and is detachably attached to the ink jet recording apparatus. At the time of mounting, the drain needle 242 attached to the tip of the drain tube 240 is punctured into the waste ink absorber 310 from the opening 301 of the waste ink tank 300. Further, the waste ink tank 300 is provided with an opening 302 so that the evaporation component in the waste ink absorbed and held by the waste ink absorber 310 is easily evaporated.

  In the present embodiment, the movement of the piston shaft 232, the vertical movement of the cap 210, the vertical movement of the ink tank 110, and the movement of the pit-in cap 261 can all be realized by driving the same pump motor 410. By connecting a plurality of gear trains, lead screws, and the like to the pump motor 410 while being connected in various combinations, the forward / reverse rotation drive of the pump motor is transmitted to each part according to the purpose.

  Here, a pit-in sequence for supplying a predetermined amount of ink from the ink bag 111 to the recording head 1 will be described. At the start of the pit-in sequence, each component is located at the position shown in FIG. However, it is assumed that the piston 231 is located in the rightmost direction (arrow S direction) in the drawing. Hereinafter, this piston position is referred to as bottom dead center. The air communication valve 251 is in a valve open state.

  When the pit-in sequence is started, the ink tank 110 moves in the arrow J direction. As a result, the pit-in needle 102 pierces the rubber stopper 112, and the inside of the ink bag 111 and the reserve tank 104 in the recording head unit 1 are brought into communication. Such a position of the ink tank 110 is referred to as a joint position. At the same time, the pit-in cap 261 also moves in the direction of the arrow P and comes into close contact with the periphery of the pit-in port 105 of the recording head unit 1. Thereafter, the piston 231 is moved in the drain direction (D direction) by rotating the pump motor 410 in the forward direction.

  By the movement of the piston 231, the pressure on the right side of the piston 231 in the cylinder 230 is reduced, and the air in the pit-in chamber 107 of the recording head 100 is sucked into the cylinder pump 230. Accordingly, the pressure in the pit-in chamber 107 is also reduced, and the ink in the ink bag 111 is supplied to the reserve tank 104 through the pit-in needle 102. However, since the supplied ink cannot spread above the gas-liquid separation film 108, the supply of ink stops in a state where the reserve tank 104 is filled with ink.

  Thereafter, the ink tank 110 is returned to the arrow K direction and the pit-in cap 261 is returned to the arrow T direction with the position of the piston 231 unchanged. In this way, the ink in the ink bag 111 is supplied into the reserve tank 104 of the inkjet recording head 100.

  As in this embodiment, supplying ink to the recording head by the pit-in method, or making the ink tank or waste ink tank for supplying the ink replaceable with the recording apparatus reduces the size of the recording apparatus. This is an extremely effective configuration. In this case, by integrating the ink tank 110 and the waste ink tank 300, the user's labor can be further simplified.

  Next, a recovery sequence that is a characteristic matter of the present invention will be described. The recovery sequence of the present embodiment is characterized in that the method is changed according to the elapsed time from the previous suction operation counted by the suction timer 412.

  FIG. 4 is a flowchart for explaining that the recovery sequence of this embodiment is controlled according to the elapsed time. When the recovery sequence starts, the controller 400 of the recording apparatus acquires the count value of the suction timer 412 and executes one of the three types of recovery sequences prepared according to the obtained elapsed time. When the elapsed time obtained from the suction timer 412 is less than 1200 hours, the recovery sequence 1 is executed. When the elapsed time is 1200 hours or more and less than 2400 hours, the recovery sequence 2 is executed. Further, when the elapsed time is 2400 hours or more, the recovery sequence 3 is executed.

  FIG. 5 is a flowchart for explaining each process executed by the controller 400 in the recovery sequence 2 of the present embodiment. When this sequence is started, each mechanism is assumed to be arranged at each position shown in FIG.

  When the recovery sequence 2 is started, first, the controller 400 closes the atmospheric communication valve 251 in step 21, and then rotates the pump motor 410 in the forward direction (CW direction) in step 22 to move the piston 231 to the bottom dead center. To do. Hereinafter, this operation is referred to as a suction direction stroke. The suction direction stroke at this time is completed in 4 seconds by the constant speed movement of the piston 231. In other words, the pump motor 410 is rotated at a constant speed so that the suction direction stroke is completed in 4 seconds. When the suction direction stroke is completed, the process waits for 10 seconds (step 23), and then the atmospheric communication valve 251 is opened (step 24). Through steps 21 to 24 described above, substantially all of the ink stored in the reserve tank 104 is sucked (total suction) by the cylinder pump 230.

  The recovery sequence 2 is a recovery process for the print head that has passed 1200 hours or more since the previous suction operation. Therefore, it is expected that evaporation from the nozzle port, the pit-in needle 102 and the pit-in port 105 proceeds, and the ink in the reserve tank 104 has a considerably high density and high viscosity. Therefore, in the recovery sequence 2, once the ink in the reserve tank 104 is completely sucked, the stability of the ejection operation of the recording head 100 is ensured.

  After almost all the ink in the reserve tank 104 has been discharged, the above-described pit-in sequence is executed in order to inject new ink into the reserve tank again. However, in the recovery sequence 2 of the present embodiment, the operation of discharging the ink stored in the syringe pump 230 to the waste ink tank 300 by the above-described total suction (hereinafter referred to as drain) is also performed simultaneously. As a previous stage, in step 25, the ink tank 110 is moved to the joint position described above, and the pit-in cap 261 is moved to the pit-in position described above.

  By the way, this embodiment changes the subsequent recovery operation according to the amount of ink (total suction amount) accommodated in the cylinder pump after full suction. The total suction amount can be obtained by always counting and managing the amount of ink stored in the reserve tank 104 (hereinafter referred to as QRT). A specific management method of QRT will be briefly described below.

  In the ink jet recording apparatus of this embodiment, 3 ml obtained by subtracting the volume of the ink absorbing member 103 from the volume of the reserve tank 104 is the QRT immediately after the pit-in sequence is executed. Thereafter, when ink suction is performed from the nozzle orifice surface according to the normal recovery sequence 1, the predetermined ink suction amount is reduced from QRT. In the recording operation, the multiplication value of the ejection amount per droplet and the number of ejections from the nozzle is reduced from QRT. Further, the time during which the suction operation or the recording operation is not performed is acquired from the suction timer 412, a multiplication value with the ink evaporation amount per unit time measured in advance is obtained, and this is subtracted from QRT.

  Thus, since the inkjet recording apparatus of this embodiment always manages QRT, the QRT before the total suction performed in Steps 21 to 24, that is, the amount of ink accommodated in the cylinder pump after the total suction ( The total suction amount) can be grasped.

  In step 26, the total suction amount (QRT) is referred to, and when the total suction amount is less than 1 ml, the process proceeds to step 210, and when it is 1 ml or more, the process proceeds to step 220.

  In step 210, the pump motor 410 is rotated in the direction opposite to the CW direction (hereinafter referred to as CCW direction), and the piston 231 is moved from the bottom dead center to the original position (top dead center). This operation is called a drain direction stroke. Note that the rotation of the pump motor at this time is a constant speed rotation equivalent to performing a full drain direction stroke in 8 seconds. In the present embodiment, when the piston 231 is stroked from the bottom dead center to the top dead center in the drain direction, the amount of fluid (ink + air) drained from the cylinder pump 230 is 4 ml. Therefore, in the drain direction stroke of 8 seconds performed in step 220, the fluid composed of ink and air is discharged from the cylinder pump 230 to the waste ink tank 300 at a speed of 0.5 ml / second.

  With this stroke in the drain direction, ink in the cylinder pump 230 is discharged into the waste ink tank 300, and at the same time, ink is supplied from the ink tank 110 to the reserve tank 104.

  On the other hand, if it is determined in step 26 that the total suction amount is 1 ml or more, the stroke in the drain direction by the piston 231 is performed in two stages. Specifically, first, in step 220, the pump motor 410 is rotated in the CCW direction, and the piston 231 is moved to a half position from the bottom dead center to the top dead center. Hereinafter, this operation is referred to as a drain direction half stroke. The rotation of the pump motor at this time is a constant speed rotation equivalent to a half stroke in the drain direction in 8 seconds. That is, the rotation of the pump motor 410 and the movement of the piston 231 are performed for 8 seconds at half the speed of the stroke in the drain direction performed in step 210.

  Thereafter, after waiting for 4 seconds in step 221, the remaining half stroke in the drain direction is performed in step 222. The rotational speed and operating time of the pump motor in step 222 are the same as in step 220.

  The ink in the cylinder pump 230 is discharged to the waste ink tank 300 by intermittent strokes in the drain direction in steps 220 to 222, and at the same time, the ink is supplied from the ink tank 110 to the reserve tank 104.

  In this embodiment, the method of the drain direction stroke is made different according to the amount of ink drained from the cylinder pump 230, that is, according to the total suction amount. That is, if the amount of ink to be discharged is small (less than 1 ml), the ink in the cylinder pump is discharged in one stroke. On the other hand, in a single stroke, if the amount of discharged ink is large (1 ml or more) to the extent that waste ink overflows or scatters in the vicinity of the drain opening 301, there is a low-speed stroke divided into two. Drain the ink in the cylinder pump. As described above, in this embodiment, while avoiding the overflow and scattering of ink accompanying the drain operation, the waiting time is not increased more than necessary when the amount of waste ink is small.

  When step 210 or step 222 ends, the end time is stored in the suction timer 412 (step 250). Further, in step 251, the ink tank 110 is moved in the direction of arrow K and the pit-in cap 261 is moved in the direction of arrow T to return to the original position shown in FIG.

  Next, of the ink filled in the reserve tank 104, ink that is not absorbed by the ink absorbing member 103 (hereinafter referred to as free ink) is sucked from the nozzle opening of the recording head 100 using the cylinder pump 230. . This is because if the free ink is not sucked, the free ink may leak from the pit-in needle 102 of the inkjet recording head 100 during the recording operation. In this embodiment, the amount of free ink is about 0.4 ml, and a slightly larger 0.5 ml is sucked with a margin when sucking.

  For this reason, first, in step 252, the atmosphere communication valve 251 is closed. Next, the pump motor 410 is rotated in the CW direction, and a stroke in the suction direction of the piston 231 is performed. The rotation of the pump motor 410 at this time is the same as the rotation speed at the time of full suction described above, that is, constant speed rotation equivalent to performing a suction direction stroke in 4 seconds. The free ink is gradually sucked to the syringe pump 230 side by this stroke, but the atmosphere communication valve 251 is opened at a predetermined timing (a timing at which the amount of sucked ink becomes 0.5 ml) during the suction direction stroke. (Step 253). At the time when the atmosphere communication valve 251 is opened, air is sucked into the cylinder pump 230, so that ink in the reserve tank 104 is not discharged any more. That is, approximately 2.5 ml is accommodated.

  In step 254, the cap 210 is moved down to the separated position. Thereafter, after performing a wiping operation or the like (step 255), the recording medium 8 is fed and the recording operation is started (step 2000).

  In subsequent steps 2010 to 2012, the total suction amount (previous drain amount) discharged in step 22 is classified into four stages. The drain operation for the second time, that is, the discharge of free ink, is performed after the standby by providing an appropriate standby time according to the previous drain amount.

  If the previous drain amount is less than 0.5 ml, the process proceeds to step 2020 to determine whether or not the elapsed time from the end time of the previous drain stored in step 250 has exceeded 10 seconds. When the time exceeds 10 seconds, the process proceeds to Step 2100.

  When the previous drain amount is 0.5 ml or more and 1 ml, the process proceeds to Step 2030, and it is determined whether or not the elapsed time from the last drain end time stored in Step 250 has exceeded 15 seconds. Then, when the time exceeds 15 seconds, the process proceeds to Step 2100.

  If the previous drain amount is 1 ml or more and 2 ml or less, the process proceeds to step 2040 to determine whether or not the elapsed time from the end time of the previous drain stored in step 250 has exceeded 30 seconds. When the time exceeds 30 seconds, the process proceeds to Step 2100.

  If the previous drain amount is 2 ml or more, the process proceeds to step 2050, and it is determined whether the elapsed time from the end time of the previous drain stored in step 250 has exceeded 40 seconds. Then, when the time exceeds 40 seconds, the process proceeds to Step 2100.

  In step 2100, the pump motor 410 is rotated in the CCW direction to perform a drain direction stroke. The rotation of the pump motor 410 at this time is the same speed rotation as the rotation speed in step 210. Therefore, the time required to execute step 2100 is 8 seconds. The ink sucked into the cylinder pump 230 is discharged to the waste ink tank 300 by the stroke in the drain direction in step 2100.

  In the following step 2200, the suction timer 412 stores the time when the current drain operation is completed. Thereafter, in step 2300, it is determined whether or not the recording operation started in step 2000 has been completed. If it is not completed, it waits until the recording operation is completed. If completed, this process is terminated.

  Here, the relationship between the drain operation and the recording operation performed in parallel will be described in detail for each case classified into four stages according to the total suction amount. The time required to execute the above steps 251 to 255 is about 7 seconds, and the time until the recording operation started in step 2000 is completed is about 14 seconds with the size of the recording medium 8 as the name card size.

  If the previous drain amount was less than 0.5 ml, 18 seconds including the waiting time of 10 seconds until drain start and the drain execution time of 8 seconds is stored in step 250, and the last drain time is stored. Elapsed time until is finished. On the other hand, since the recording is started after 7 seconds have elapsed since the last drain end time was stored in step 250, 11 seconds obtained by subtracting 7 seconds from 18 seconds is the recording operation in step 2000. Is the time from the start to the end of the current drain. Therefore, if this value is compared with the actual recording operation time of 14 seconds, it can be seen that the recording operation ends after 3 seconds have elapsed since the drain operation executed in step 1200 is completed. That is, since the drain operation is completed while the recording operation is being performed, no extra time is consumed by the drain operation.

  Considering similarly when the previous drain amount was 0.5 ml or more and less than 1 ml, in this case, the drain operation is completed 2 seconds after the recording operation is completed. Also, if the previous drain amount was 1 ml or more and less than 2 ml, the drain operation was completed 17 seconds after the recording operation was completed, and if the previous drain amount was 2 ml or more, the recording operation was completed. The drain operation is completed 27 seconds later.

  In the recovery sequence 2, taking into account that the time during which the previous waste ink is absorbed by the waste ink absorber 310 differs depending on the amount of waste ink (previous drain amount), the larger the previous drain amount, the more until the next drain is performed. The waiting time is set longer. As a result, while avoiding overflow and scattering of ink at the drain opening 301, it is expected that the absorption of the waste ink will be completed relatively early, for example, when the previous drain amount was less than 0.5 ml. In such a case, the waiting time is not set longer than necessary.

  In an actual recording operation, it is common to perform a preliminary ejection operation or a wiping operation of the recording head 100 immediately before the start of the recording operation. Therefore, when performing the recording operation continuously, the above operation is performed after the recording on the first recording medium is completed and before the recording on the next recording medium is started. At this time, if the drain operation is being executed at the time when the recording operation is completed such that the previous drain amount is 0.5 ml or more, the preliminary ejection operation or wiping using the recovery system mechanism is performed even if the recording operation is completed. The action cannot be executed immediately. As a result, after the current drain operation is completed, the preliminary ejection operation and the wiping operation are performed, and then the next page recording operation is started. In other words, from the viewpoint of throughput, the drain operation is completed at a timing earlier than the recording operation as much as possible, and even if the drain operation is longer, the drain operation is performed in a short time from the point when the recording operation is completed as much as possible. Is desired to be completed.

  FIG. 6 is a flowchart for explaining each process executed by the controller 400 in the recovery sequence 3 of the present embodiment. The recovery sequence 3 is a sequence executed when the elapsed time from the previous suction operation is 1400 hours or more. Therefore, compared with the case where the recovery sequence 2 is executed, evaporation from the nozzle port, the pit-in needle 102 and the pit-in port 105 further proceeds, and the ink in the reserve tank 104 has a higher density and higher viscosity. It is expected that. Therefore, in the recovery sequence 3, after all the ink in the reserve tank 104 is sucked and the pit-in sequence is executed, the second suction amount to be further sucked is 1.8 times (0.9 ml) of 0.5 ml of the recovery sequence 2. ). As a result, in the second suction operation, in addition to free ink, high-viscosity ink remaining in the ink absorbing member 103 (high-concentration ink that cannot be removed only by full suction) is also reliably suctioned, and thereafter The stability of the ejection operation of the recording head 100 can be maintained.

  Also in the recovery sequence 3, steps 31 to 352 are the same as those in the recovery sequence 2. Also in step 353, the pump motor 410 is rotated in the CW direction as in step 253, and the stroke in the suction direction of the piston 231 is performed at a rotational speed equal to that in step 253. However, in the recovery sequence 3, 0.9 ml of ink is sucked by this suction operation. Therefore, opening the air communication valve during the suction direction stroke is delayed from the recovery sequence 2 step 253.

  Each process from step 354 to step 3012 is also equivalent to step 254 to step 2012 of the recovery sequence 2.

  In the recovery sequence 3, when the previous drain amount is less than 0.5 ml, the process proceeds to step 3020, and it is determined whether or not the elapsed time from the end time of the previous drain stored in step 350 has exceeded 15 seconds. When the time exceeds 15 seconds, the process proceeds to step 3100.

  If the previous drain amount is 0.5 ml or more and 1 ml, the process proceeds to step 3030 to determine whether or not the elapsed time from the last drain end time stored in step 350 has exceeded 20 seconds. When the time exceeds 20 seconds, the process proceeds to step 3100.

  When the previous drain amount is 1 ml or more and 2 ml or less, the process proceeds to step 3040 to determine whether or not the elapsed time from the end time of the previous drain stored in step 350 has exceeded 40 seconds. When the time exceeds 40 seconds, the process proceeds to step 3100.

  If the previous drain amount is 2 ml or more, the process proceeds to step 3050 to determine whether or not the elapsed time from the end time of the previous drain stored in step 350 has exceeded 50 seconds. When the time exceeds 50 seconds, the process proceeds to step 3100.

  In step 3100, the pump motor 410 is rotated in the CCW direction at the same rotational speed as in the recovery sequence 2 to perform a drain direction stroke. Therefore, the time required to execute step 3100 is also 8 seconds. The ink sucked into the cylinder pump 230 is discharged to the waste ink tank 300 by the stroke in the drain direction in step 2100.

  In the following step 3200, the time when the current drain operation is completed is stored in the suction timer 412. Thereafter, in step 3300, it is determined whether or not the recording operation started in step 3000 has been completed. If it is not completed, it waits until the recording operation is completed. If completed, this process is terminated.

  Here, the relationship between the drain operation and the recording operation performed in parallel will be specifically described for each case classified into four stages according to the total suction amount in the recovery sequence 3. If the previous drain amount was less than 0.5 ml, the drain operation is completed 2 seconds after the recording operation is completed. Also, if the previous drain amount was 0.5 ml or more and less than 1 ml, the drain operation was completed 7 seconds after the recording operation was completed, and if the previous drain amount was 1 ml or more and less than 2 ml, the recording operation was completed. The drain operation is completed 27 seconds after the operation is completed. Furthermore, if the previous drain amount was 2 ml or more, the drain operation is completed 37 seconds after the recording operation is completed.

  Also in the recovery sequence 3, taking into account that the time during which the previous waste ink is absorbed by the waste ink absorber 310 differs depending on the amount of waste ink (previous drain amount), the larger the previous drain amount, the more until the next drain is performed. The waiting time is set longer. Furthermore, since the amount of ink sucked in step 353 is larger than in the case of the recovery sequence 2, the standby time until the next drain is performed is set to be relatively longer than in the cases of the recovery sequence 2. As a result, even when there is a greater concern about the overflow or scattering of ink at the drain opening 301, this is avoided and at the same time, the standby time is not set longer than necessary.

  Referring to FIG. 4 again, when the elapsed time obtained from the suction timer 412 is less than 1200 hours, the recovery sequence 1 is executed. The recovery sequence 1 is a recovery process for a recording head in which a time of 1200 hours or more has not elapsed since the previous suction operation. Therefore, unlike the recovery sequence 2 and the recovery sequence 3, it can be predicted that the ink in the reserve tank 104 has not changed so much. Therefore, in the recovery sequence 1, the total suction is not performed, and the process can be started from step 252 or step 352 shown in FIG. 5 or FIG. 6. Then, after the recording operation is started in step 2000 or step 3000, it is possible to immediately shift to the stroke in the drain direction (step 2100 or step 3100) regardless of the previous drain amount. When there is no concern about the change in the ink density in the reserve tank or the overflow and scattering of the vicinity of the drain opening 301, the simple suction operation with a low ink consumption and time cost as in the recovery sequence 1 can be used. Discharge stability can be ensured.

  As described above, in the present embodiment, the ink suction amount to the cylinder pump and the timing or stroke speed of the drain operation from the cylinder pump to the waste ink tank according to the elapsed time and the suction amount from the previous suction operation. Has changed. In other words, when there is a strong concern about overflow or scattering of ink at the drain opening, the timing of draining ink from the cylinder pump to the waste ink tank is delayed, and when there is little concern about overflow or scattering, the drain operation is performed more quickly. Control to complete. This makes it possible to avoid leakage and scattering of ink as much as possible without providing standby time more than necessary.

(Other embodiments)
In the above embodiment, the recovery includes the step of changing the stroke speed according to the current drain amount (steps 210 to 222) and the step of changing the next drain timing according to the previous drain amount (steps 2010 to 2050). The sequence has been described. However, the ink absorption capacity in the waste ink tank does not depend only on the previous or current drain amount. For example, if a sufficient time has elapsed since the previous drain operation, it is expected that the absorption capacity of the absorber is sufficiently recovered even if the drain amount of the previous time or this time is large to some extent. In other words, not only by adjusting the drain timing of the previous time or current time but also by adjusting the next drain timing and drain speed according to the elapsed time from the previous drain operation (the elapsed time stored in step 250 or 2200). The object of the invention can be realized. In this case, specifically, as the elapsed time from the previous drain operation is smaller, the next drain timing is delayed or the next drain speed is decreased.

  Further, in the above, for the sake of simplicity of explanation, the configuration of the ink jet recording apparatus using one recording head 100 and one ink tank 110 has been described. However, the present invention can also be applied to a color ink jet recording apparatus including a plurality of recording heads that eject different inks and a plurality of ink tanks that store the respective inks. In this case, a cylinder pump and a waste ink tank common to a plurality of recording heads may be prepared, or a separate cylinder pump and a waste ink tank may be prepared for each ink color. When the waste ink tank is prepared for each color, the waste ink tank and the ink tank can be configured integrally.

  In addition, in the above-described embodiment, the description has been given of the configuration in which the ink is sucked and discharged and supplied to the reserve tank by the constant speed movement of the piston 231 provided in one cylinder pump. It does not have to be realized by fast movement. Further, the ink suction / discharge and the ink supply to the reserve tank may be performed by separate pump means.

  Furthermore, in the above-described embodiment, an ink jet recording apparatus that forms an image on a recording medium by ejecting ink according to image data has been described as an example. However, the present invention is not limited to this. According to the present invention, in a configuration in which liquid is intermittently transported toward a unit (for example, a waste ink tank) that holds liquid (for example, ink) to be discharged, according to the elapsed time from the previous transport and the transport amount from time to time. This is because the next transport timing and flow velocity are adjusted.

1 is a diagram for explaining a schematic configuration of an ink jet recording apparatus applicable to the present invention. It is a block diagram for demonstrating the structure of control in the inkjet recording device applicable to this invention. It is a schematic diagram for demonstrating the ink supply system and recovery system mechanism in embodiment of this invention. It is a flowchart for demonstrating controlling a recovery sequence according to elapsed time. It is a flowchart for demonstrating each process which a controller performs in the recovery sequence 2 of embodiment applied by this invention. It is a flowchart for demonstrating each process which a controller performs in the recovery sequence 3 of embodiment applied by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording head unit 2 Carriage 3 Guide shaft 4 Main scanning motor 5 Motor pulley 6 Driven pulley 7 Timing belt 8 Recording medium 9 Conveyance roller 10 Home position sensor 11 Shielding plate 12 Paper end sensor 13 Pickup roller 14 Auto sheet feeder (ASF)
DESCRIPTION OF SYMBOLS 15 Feed motor 16 Line feed motor 100 Recording head 101 Nozzle port surface 102 Pit-in needle 103 Ink absorption member 104 Reserve tank 105 Pit-in port 106 Ink supply port 107 Pit-in chamber 108 Gas-liquid separation film 110 Ink tank 111 Ink bag 112 Rubber plug 210 Cap 215 Ink absorber 220 Suction tube 221 One-way valve 230 Cylinder pump 231 Piston 232 Piston shaft 240 Drain tube 241 One-way valve 242 Drain needle 250 Atmospheric communication tube 251 Atmospheric communication valve 260 Pit in tube 261 Pit in cap 300 Waste ink tank 301 Drain Opening 302 Opening 310 Waste ink absorber 400 Controller 401 CPU
402 ROM
403 RAM
404 Host device 405 Interface 406 Head driver 407 Main scanning motor driver 408 Line feed motor driver 409 Pump motor driver 410 Pump motor 412 Suction timer

Claims (10)

In a liquid discharge device that discharges waste liquid intermittently to a waste liquid holding means having an absorber that absorbs liquid,
Means for acquiring the amount of waste liquid discharged each time, and at least one of the timing of the next waste liquid discharge or the discharge speed to the waste liquid holding means differs according to at least one of the previous waste liquid discharge amount or the next waste liquid discharge amount. A liquid discharging apparatus characterized by having   2. The liquid discharge apparatus according to claim 1, wherein the discharge speed is reduced as the previous waste liquid discharge amount or the next waste liquid discharge amount increases.   The liquid discharging apparatus according to claim 1, wherein the timing of the next waste liquid discharge is delayed as the previous waste liquid discharge amount or the next waste liquid discharge amount increases.   A means for measuring an elapsed time from the previous waste liquid discharge is further provided, and according to at least one of the previous waste liquid discharge amount, the next waste liquid discharge amount, and the elapsed time, 2. The liquid discharge apparatus according to claim 1, wherein at least one of discharge speeds to the waste liquid holding means is made different.   The liquid discharging apparatus according to claim 4, wherein the discharging speed is decreased as the elapsed time is shorter.   The liquid discharging apparatus according to claim 4, wherein the timing of discharging the next waste liquid is delayed as the elapsed time is shorter.   7. The liquid discharging apparatus according to claim 1, wherein the waste liquid holding means is detachable. A recording head having a nozzle for ejecting ink;
Ink sucked from the nozzles by moving a piston disposed therein in a first direction, and sucked by moving the piston in a second direction opposite to the first direction. A cylinder pump for discharging,
Waste ink holding means comprising an absorber for absorbing ink discharged from the cylinder pump;
An ink jet recording apparatus comprising: means for acquiring a discharge amount of ink discharged with one movement of the piston in the second direction; and means for measuring an elapsed time from the previous discharge. And
According to at least one of the elapsed time, the previous discharge amount, and the next discharge amount, at least one of the next ink discharge timing or the discharge speed for the waste ink holding unit is made different. Inkjet recording apparatus.   9. The ink jet recording apparatus according to claim 8, wherein new ink is supplied to the recording head simultaneously with the discharging by moving the piston in the second direction. A step of sucking ink from a nozzle that discharges ink according to discharge data by moving a piston disposed inside the cylinder pump in a first direction;
Discharging the ink sucked by the suction step by moving the piston in a second direction opposite to the first direction to a waste ink holding means having an absorber;
A recovery processing method for an ink jet recording apparatus comprising a step of measuring an elapsed time from the discharging step,
Depending on at least one of the elapsed time, the ink discharge amount in the previous discharge step, and the ink discharge amount in the next discharge step, at least one of the timing of executing the next discharge step or the discharge speed is varied. A recovery processing method for an ink jet recording apparatus.

Images