JP2010194829A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the discharge defect of a recording head occurs, in stopping the operation when a detachable waste liquid tank is detached during maintaining restoring movement. <P>SOLUTION: Waste liquid discharging channels are constituted of a tube 310 connected to a suction pump 220, a tube 311 connected to the exchangeable first waste liquid tank 101, and a tube 312 connected to the second waste liquid tank 102, a three-way solenoid valve 300 is arranged for shifting the discharging channels between tube 310 and tubes 311, 312, the tubes 310, 311 are put in communication and the waste liquid discharging channel is formed in the first waste liquid tank 101 side and the second waste liquid tank 102 side is blocked when the first waste liquid tank 101 is installed, the waste liquid discharging channel is shifted to the second waste liquid tank 102 side, and the first waste liquid tank 101 side is blocked when the first waste liquid tank 101 is detached. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus including a waste liquid tank that stores a waste liquid generated by a maintenance recovery operation of a recording head that discharges droplets.

  As an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, a plotter, and a complex machine of these, for example, an ink jet recording apparatus is known as an image forming apparatus of a liquid discharge recording method using a recording head for discharging ink droplets. . This liquid discharge recording type image forming apparatus ejects ink droplets from a recording head onto a conveyed paper to form an image (recording, printing, printing, and printing are also used synonymously). Serial type image forming device that forms an image by ejecting droplets while the recording head moves in the main scanning direction, and a line type that forms images by ejecting droplets without the recording head moving There is a line type image forming apparatus using a head.

  In the present application, “image forming apparatus” means an apparatus for forming an image by landing ink on a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. "Image formation" is not only the application of images with meanings such as characters and figures to the medium, but also the addition of images with no meaning such as patterns to the medium (simply applying droplets to the medium) Also means landing). The “ink” is not limited to the ink, but is used as a general term for all liquids that can perform image formation, such as a recording liquid, a fixing processing liquid, and a liquid. The term “paper” is not limited to paper, but includes the above-described OHP sheet, cloth, and the like, and means that ink droplets adhere to the recording medium, recording medium, recording paper, recording It is used as a general term for what includes what is called paper.

  In such an image forming apparatus (hereinafter, also simply referred to as “inkjet recording apparatus”), the recording head is caused by the evaporation of the solvent from the nozzle because of recording by discharging ink from the nozzle onto the paper. Maintenance and recovery to maintain and recover the performance of the print head due to problems such as increased ink viscosity, ink solidification, dust adhesion, and bubble failure due to air bubbles. It has a mechanism.

  For example, a cap (also referred to as a capping unit or a cap member) that seals the nozzles of the recording head is provided, and capping of the recording head is performed when the apparatus is not in operation, thereby suppressing drying and thickening of ink in the nozzles. To be able to. In addition, before and after the recording operation or during the recording operation, ink droplets that do not contribute to the recording operation (empty ejection, refreshing, etc.) are performed, or the recording head is capped with a cap when left for a predetermined time. By operating the suction pump, negative pressure is generated in the cap, ink is sucked from the nozzle, and the dried and thickened ink is discharged in the nozzle to recover and maintain the discharge performance. .

  In general, the waste liquid of ink generated in such a maintenance and recovery operation is stored in a dedicated waste liquid tank or shared with an ink cartridge. For example, in order to increase the absorption efficiency of the absorbing member in the waste liquid tank, a branch part is provided in the waste liquid path, and the waste liquid is discharged by distributing it to a plurality of waste liquid tanks (Patent Document 1), and a branch part is provided in the waste liquid path. A configuration in which one is connected to a waste liquid tank and the other is connected to an ink tank (Patent Document 2) is known. Patent Document 1 also discloses that when the waste liquid tank is removed, the image recording operation or the maintenance / recovery operation is interrupted, and when the waste liquid tank is attached, a sequence of restarting the operation is performed.

JP 2007-98777 A JP 2002-86763 A

  The waste liquid tank preferably has a volume larger than the capacity of the ink discharged before the lifetime of the image forming apparatus. However, increasing the capacity of the waste liquid tank leads to an increase in the size of the image forming apparatus. The waste liquid tank is detachably (replaceable) from the image forming apparatus main body.

  However, when the waste liquid tank is made detachable, if the waste liquid tank is removed during the image recording operation or the maintenance recovery operation, the waste liquid may be discharged into the image forming apparatus and the inside of the apparatus may be contaminated with the waste liquid.

  Therefore, as described above, when the waste liquid tank is removed, the image recording operation or the maintenance / recovery operation is interrupted, and when the waste liquid tank is attached, a sequence of restarting the operation can be performed.

  However, even when such a sequence is performed, if the operation is interrupted during the operation of sucking and discharging ink from the recording head in the maintenance and recovery operation, a negative pressure may not be formed in the recording head. If the apparatus is left in this state for a long period of time, ink may drip from the recording head, which may cause ejection failure or ejection failure of the recording head.

  The present invention has been made in view of the above problems, and even when the waste liquid tank is removed during the image recording operation or the maintenance recovery operation, the operation can be continued without contaminating the inside of the image forming apparatus with the waste liquid. The purpose is to be able to.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
A recording head having nozzles for discharging ink droplets;
A cap for capping the nozzle surface of the recording head;
Suction means for forming a negative pressure in the space sealed with the cap;
A first waste liquid tank for storing ink waste liquid;
A second waste liquid tank for storing ink waste liquid;
A waste liquid discharge path through the suction means and the first and second waste liquid tanks;
When the first waste liquid tank is attached, the waste liquid discharge path to the first waste liquid tank side is cut off from the waste liquid discharge path to the second waste liquid tank side,
A discharge path switching means for setting the waste liquid discharge path to the second waste liquid tank side and shutting off the waste liquid discharge path to the first waste liquid tank side when the first waste liquid tank is removed. The configuration.

  Here, the waste liquid discharge path has a branch portion branched into the first waste liquid tank side and the second waste liquid tank side, and the discharge path switching means is a solenoid valve provided in the branch portion. it can.

  Further, the waste liquid discharge path has a branch portion branched into the first waste liquid tank side and the second waste liquid tank side, and the discharge path switching means is between the branch portion and the first waste liquid tank and the It can be set as the structure which is a solenoid valve each provided between the branch part and the said 2nd waste liquid tank.

  Further, the discharge path switching means can be configured to switch the waste liquid discharge path in conjunction with the attaching / detaching operation of the first waste liquid tank.

  Further, the waste liquid discharge path is formed of an elastic member, and has a branch portion branched into the first waste liquid tank side and the second waste liquid tank side, and the discharge path switching means includes the branch portion and the first waste liquid. A member may be provided between the tank and between the branch portion and the second waste liquid tank to crush the waste liquid discharge path.

  In addition, at least one of the first waste liquid tank and the second waste liquid tank may have a substantially sealed structure and an absorption member is provided inside.

  According to the image forming apparatus of the present invention, when the first waste liquid tank is attached, the waste liquid discharge path is set to the first waste liquid tank side, the waste liquid discharge path to the second waste liquid tank side is shut off, and the first waste liquid is When the tank is removed, there is provided a discharge path switching means for setting the waste liquid discharge path to the second waste liquid tank side and blocking the waste liquid discharge path to the first waste liquid tank side. Even when the first waste liquid tank is removed, the operation can be continued without contaminating the inside of the image forming apparatus with the waste liquid.

1 is a configuration diagram showing an outline of a mechanism part of an image forming apparatus according to the present invention. It is principal part plane explanatory drawing of the mechanism part. It is a schematic model side surface explanatory view of a maintenance recovery mechanism. Similarly it is principal part plane explanatory drawing. It is a perspective explanatory view similarly. It is side explanatory drawing of FIG. It is a cross-sectional perspective explanatory view of the waste liquid tank. It is typical explanatory drawing with which it uses for description of 1st Embodiment of this invention. It is typical explanatory drawing with which it uses for description of the embodiment. It is typical explanatory drawing with which it uses for description of 2nd Embodiment of this invention. It is typical explanatory drawing with which it uses for description of the embodiment. It is typical explanatory drawing with which it uses for description of 3rd Embodiment of this invention. It is typical explanatory drawing with which it uses for description of the embodiment. It is typical explanatory drawing with which it uses for description of 4th Embodiment of this invention. It is typical explanatory drawing with which it uses for description of the embodiment.

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an example of an image forming apparatus according to the present invention will be described with reference to FIGS. FIG. 1 is an explanatory side view for explaining the overall configuration of the image forming apparatus, and FIG. 2 is an explanatory plan view of a main part of the apparatus.
This image forming apparatus is a serial type ink jet recording apparatus, and a carriage 33 is slidable in a main scanning direction by main and sub guide rods 31 and 32 which are guide members horizontally mounted on the left and right side plates 21A and 21B of the apparatus main body 1. It is held and moved and scanned in the direction indicated by the arrow (carriage main scanning direction) in FIG. 2 via a timing belt by a main scanning motor (not shown).

  The carriage 33 is provided with recording heads 34a and 34b composed of liquid ejection heads for ejecting ink droplets of yellow (Y), cyan (C), magenta (M), and black (K). The “recording head 34” is arranged in a sub-scanning direction orthogonal to the main scanning direction, and the ink droplet ejection direction is directed downward.

  Each of the recording heads 34 has two nozzle rows. One nozzle row of the recording head 34a has black (K) droplets, the other nozzle row has cyan (C) droplets, and the recording head 34b has one nozzle row. One nozzle row ejects magenta (M) droplets, and the other nozzle row ejects yellow (Y) droplets.

  The carriage 33 is equipped with sub tanks 35a and 35b (referred to as “sub tanks 35” when not distinguished) for supplying ink of each color corresponding to the nozzle rows of the recording head 34. The sub tank 35 is replenished and supplied with ink of each color from the ink cartridges 10 y, 10 m, 10 c, and 10 k of each color that is detachably attached to the cartridge loading unit 4 via the supply tube 36 of each color by the supply pump unit 5. Is done.

  On the other hand, as a paper feeding unit for feeding the papers 42 stacked on the paper stacking unit (pressure plate) 41 of the paper feeding tray 2, a half-moon roller (feeding) that separates and feeds the papers 42 one by one from the paper stacking unit 41. A separation pad 44 made of a material having a large friction coefficient is provided facing the paper roller 43) and the paper feed roller 43, and the separation pad 44 is urged toward the paper feed roller 43 side.

  In order to feed the paper 42 fed from the paper feeding unit to the lower side of the recording head 34, a guide member 45 for guiding the paper 42, a counter roller 46, a transport guide member 47, and a tip pressure roller. And a holding belt 48 which is a conveying means for electrostatically attracting the fed paper 42 and conveying it at a position facing the recording head 34.

  The transport belt 51 is an endless belt, and is configured to wrap around the transport roller 52 and the tension roller 53 and circulate in the belt transport direction (sub-scanning direction). Further, a charging roller 56 that is a charging unit for charging the surface of the transport belt 51 is provided. The charging roller 56 is disposed so as to come into contact with the surface layer of the transport belt 51 and to rotate following the rotation of the transport belt 51. The transport belt 51 rotates in the belt transport direction of FIG. 2 when the transport roller 52 is rotationally driven through timing by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 42 recorded by the recording head 34, a separation claw 61 for separating the paper 42 from the conveying belt 51, a paper discharge roller 62, and a spur 63 that is a paper discharge roller. And a paper discharge tray 3 below the paper discharge roller 62.

  A duplex unit 71 is detachably mounted on the back surface of the apparatus body 1. The duplex unit 71 takes in the paper 42 returned by the reverse rotation of the conveyance belt 51, reverses it, and feeds it again between the counter roller 46 and the conveyance belt 51. The upper surface of the duplex unit 71 is a manual feed tray 72.

  Further, as shown in FIG. 2, a maintenance / recovery mechanism 81 for maintaining and recovering the state of the nozzles of the recording head 34 is disposed in the non-printing area on one side of the carriage 33 in the scanning direction. The maintenance / recovery mechanism 81 includes cap members (hereinafter referred to as “caps”) 82a and 82b (hereinafter referred to as “caps 82” when not distinguished from each other) for capping the nozzle surfaces of the recording head 34, and nozzle surfaces. A wiper member (wiper blade) 83 for wiping the recording medium, an empty discharge receiver 84 for receiving liquid droplets when performing empty discharge for discharging liquid droplets that do not contribute to recording in order to discharge the thickened recording liquid, and a carriage And a carriage lock 87 for locking 33.

  Further, the second waste liquid tank 102 that is not exchanged for storing the waste liquid generated by the maintenance recovery operation is exchanged on the lower side of the maintenance recovery mechanism 81 from the front side of the apparatus main body on the side of the maintenance recovery mechanism 81. Each possible first waste liquid tank 101 is provided.

  In addition, as shown in FIG. 2, in the non-printing area on the other side in the scanning direction of the carriage 33, idle discharge is performed to discharge liquid droplets that do not contribute to recording in order to discharge the recording liquid thickened during recording or the like. An empty discharge receiver 88 for receiving the liquid droplets at the time is disposed, and the empty discharge receiver 88 is provided with an opening 89 along the nozzle row direction of the recording head 34.

  In this image forming apparatus configured as described above, the sheets 42 are separated and fed one by one from the sheet feed tray 2, and the sheet 42 fed substantially vertically upward is guided by the guide 45, and includes the transport belt 51 and the counter. It is sandwiched between the rollers 46 and conveyed, and the leading end is guided by the conveying guide 37 and pressed against the conveying belt 51 by the leading end pressing roller 49, and the conveying direction is changed by approximately 90 °.

  At this time, a positive output and a negative output are alternately repeated with respect to the charging roller 56, that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 51 alternates, that is, in a sub-scanning direction that is a circumferential direction. , Plus and minus are alternately charged in a band shape with a predetermined width. When the paper 42 is fed onto the conveyance belt 51 charged alternately with plus and minus, the paper 42 is attracted to the conveyance belt 51, and the paper 42 is conveyed in the sub-scanning direction by the circular movement of the conveyance belt 51.

  Therefore, by driving the recording head 34 according to the image signal while moving the carriage 33, ink droplets are ejected onto the stopped paper 42 to record one line, and after the paper 42 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 42 has reached the recording area, the recording operation is finished and the paper 42 is discharged onto the paper discharge tray 3.

  When performing the maintenance and recovery of the nozzles of the recording head 34, the nozzle 33 performs the suction from the nozzles by moving the carriage 33 to a position facing the maintenance and recovery mechanism 81 which is the home position and performing capping by the cap member 82. By performing a maintenance and recovery operation such as idle ejection for ejecting droplets that do not contribute to image formation, image formation by stable droplet ejection can be performed.

Next, the maintenance / recovery mechanism 81 in this image forming apparatus will be described with reference to FIGS. 3 is a schematic schematic configuration diagram of the maintenance and recovery mechanism, and FIG.
In the maintenance / recovery mechanism 81, caps 82 a and 82 b held by the cap holder 212, a wiper member 83 including an elastic body, and a wiper cleaner 86 as a first wiper cleaning unit can be moved up and down on the maintenance device frame 211. (Can move up and down).

  The cap 82 is a box-shaped member having an opening on the side facing the nozzle surface of the recording head 34. The cap 82 has an elastic portion on the upper surface portion of the opening, and the opening of the nozzle can be sealed (capped) by bringing the elastic portion into contact with and closely contacting the nozzle surface. In the cap 82, an absorbent member (not shown) that is a porous sponge-like member is disposed. Accordingly, the capillary force of the absorbing member holds the ink in the cap 82 in a uniform state, and at the same time, the negative pressure discharged when the ink in the cap 82a is discharged by the suction pump 220 described later is transmitted to the entire cap. Can be made.

  A cylindrical empty discharge receiver 84 is disposed between the wiper member 83 and the suction cap 82a. The upper end of the empty discharge receiver 84 on the wiper member 83 side scrapes ink adhering to the wiper member 83. A wiper cleaner portion 85 is formed as a second wiper cleaning means for dropping and removing. When cleaning the wiper member 83, the wiper member 83 is lowered while the wiper member 83 is pressed against the wiper cleaner portion 85 by the wiper cleaner 86, so that the ink adhering to the wiper member 83 is scraped off to the empty ejection receiver 84 side. .

  Further, a tubing pump (suction pump) 220 as suction means is connected to the cap 82a closest to the printing area via a flexible suction tube 219 made of an elastic member as a tube member, and only the cap 82a is suctioned. (Recovery) and moisturizing cap (hereinafter simply referred to as “suction cap”), and the cap 82b is merely a moisturizing cap. Therefore, when performing the recovery operation of the recording head 34, the recording head 34 that performs the recovery operation is selectively moved to a position where it can be capped by the suction cap 82a.

  The suction pump 220 generates suction force on the tube 210 by repeatedly pressing and moving the suction tube 219 with a plurality of pressure members.

  On the other hand, below the caps 82a and 82b, the wiper member 83 and the like, a cam shaft 221 rotatably supported by the frame 211 is disposed, and on this cam shaft 221, a cap cam 222 for raising and lowering the cap holder 212, A wiper cam 224 for raising and lowering the wiper member 83, a roller 226 as a rotating body to which droplets discharged in the idle discharge receptacle 84 are applied, a cleaner cam 228 for swinging the wiper cleaner 86, and a carriage lock 87 are provided. A carriage lock cam 229 for raising and lowering is provided.

  Then, in order to rotationally drive the suction pump 220 and the cam shaft 221, the rotation of the maintenance and recovery motor 231 is meshed with the motor gear 232 provided on the motor shaft 231a and the pump gear 233 provided on the pump shaft 220a of the suction pump 220, Further, an intermediate gear 236 with a one-way clutch 237 is engaged with an intermediate gear 234 integrated with the pump gear 233 via an intermediate gear 235, and the cam shaft 221 is connected to an intermediate gear 238 coaxial with the intermediate gear 236 via an intermediate gear 239. The cam gear 240 fixed to the mesh is engaged. The intermediate shaft 241 that is the rotation shaft of the intermediate gears 236 and 238 with the clutch 237 is rotatably held by the frame 211.

  In this maintenance / recovery mechanism 81, when removing ink and impurities adhering to the surface (nozzle surface) where the nozzles of the recording head 34 are formed, the motor 231 is driven and the wiper member 83 is raised via the wiper cam 224. In this state, by moving the carriage 33 in the main scanning direction, the wiper member 83 wipes the nozzle surface of the recording head 34 to wipe away impurities and the like.

  Further, if the nozzles of the recording head 34 are left exposed to the outside air, the ink in the inside dries and thickens and adheres, and the ink ejection performance is deteriorated. To prevent this, the recording head 34 is prevented. When the nozzle surface is covered with the cap 82, the motor 231 is rotated, the cap 82 is raised via the cap cam 213, and the nozzle surface of the recording head 34 is capped.

  In addition, before and after the recording operation and during the recording operation, ink droplets that do not contribute to the recording operation are ejected (preliminary ejection) to the cap 82a to maintain the nozzle ejection performance.

Next, the waste liquid tank will be described with reference to FIGS. 5 is a perspective view of the maintenance and recovery mechanism and the waste liquid tank, FIG. 6 is a side view of the same, and FIG. 7 is a sectional perspective view of the waste tank.
In this image forming apparatus, as described above, the fixed second waste liquid tank 102 that stores and holds the waste liquid (waste ink) from the idle discharge receiver 84 of the maintenance recovery mechanism 81 and the waste liquid discharged from the cap 82a are stored and held. The first waste liquid tank 101 is detachably attached to the maintenance / recovery mechanism 81.

  The first waste liquid tank 101 is a substantially sealed container formed by a container body 111 and a lid member 112, and is a fibrous nonwoven fabric or sponge-like absorber that absorbs and retains ink (waste liquid) inside. An absorption member 113 having a multilayer structure (here, a three-layer structure) is provided. A part of the absorbing member 113 is cut out to form an input space 114 for supplying the waste liquid. Further, the absorbing member 113 has a space 115 formed through three layers on the back side with respect to the charging space 114, and an air vent hole 116 is formed in the lid member 112 corresponding to the space 115.

  The suction tube 219 of the maintenance / recovery mechanism 81 is connected to the waste liquid tank 101 by inserting the joint portion 120 into the elastic member 118 provided in the introduction port portion 117 of the waste liquid tank 101. The joint portion 120 has a hollow needle shape, and discharges the waste liquid sent from the suction tube 219 through the opening 121 formed at the distal end portion into the input space 114.

  As described above, the waste liquid tank 101 is mounted so as to be detachable from the front surface of the main body of the image forming apparatus, and can be replaced by the user. When replacing the waste liquid tank 101, in order to prevent the waste liquid from overflowing or seeping out from the waste liquid tank 101, the waste liquid tank 101 has a small number of openings and is in a state that is almost as close as possible (substantially sealed). It is configured to hold waste liquid. Further, by holding the waste liquid in a substantially sealed state, it is possible to prevent water evaporation of the waste liquid.

Next, a waste liquid discharge path switching mechanism according to the first embodiment of the present invention applied to such an image forming apparatus will be described with reference to FIGS.
The suction tube 219 forming the waste liquid discharge path includes a tube 310 connected to the suction pump 220, a tube 311 connected to the first waste liquid tank 101, and a tube 312 connected to the second waste liquid tank 102. Between the tube 310 and the tubes 311, 312, there is provided a three-way solenoid valve 300 which is a waste liquid discharge path switching means for switching the discharge path.

  This three-way solenoid valve 300 is switched by the switching drive control unit 400 according to the detection result of the waste liquid tank detection means 306 that detects whether or not the first waste liquid tank 101 is attached, and the tube 310 and the tubes 311 and 312 are communicated with each other. Switch. The waste tank detection means 306 is configured by reading means for reading information on an ID chip provided in the first waste liquid tank 101, or a photo sensor or mechanical switch means.

  The operation of this embodiment will be described. As described above, the maintenance / recovery mechanism 81 sucks ink from the nozzles of the recording head 34 by capping the nozzle surface of the recording head 34 with the cap 82a and driving the suction pump 220 to create a negative pressure in the space inside the cap 82a. In addition, the ink is discharged, and idle discharge is performed toward the cap 82a. The ink waste liquid discharged into the cap 82a is discharged through the suction tube 219 when the suction pump 220 is driven.

  Here, when it is detected by the waste liquid tank detection means 306 that the first waste liquid tank 101 is mounted, the three-way solenoid valve 300 is in a state where the tube 310 and the tube 311 are communicated as shown in FIG. The waste liquid discharge path downstream of the suction pump 220 is controlled to the first waste liquid tank 101 side, the second waste liquid tank 102 side is shut off, and the waste liquid is discharged to the first waste liquid tank 101.

  When the waste liquid tank detecting means 306 detects that the first waste liquid tank 101 has been removed, the three-way solenoid valve 300 is controlled to be switched to a state in which the tube 310 and the tube 312 are in communication as shown in FIG. The waste liquid discharge path downstream from the suction pump 220 is on the second waste liquid tank 102 side, the first waste liquid tank 101 side is shut off, and the waste liquid is discharged to the second waste liquid tank 102.

  Therefore, even if the first waste liquid tank 101 is removed during the image recording operation or the maintenance recovery operation in which the idle discharge is performed, the waste liquid discharge path is switched to the second waste liquid tank 102 side, and the waste liquid can be discharged. Various operations can be continued without polluting the forming apparatus with waste liquid.

  Here, although the second waste liquid tank 102 is constituted by a container different from the apparatus main body, it can also be constituted by a frame member of the apparatus main body. Further, the volume of the second waste liquid tank 102 is preferably smaller than the volume of the replaceable first waste liquid tank 101. When the volume of the second waste liquid tank 102 is increased in a limited space, the volume of the first waste tank 101 is reduced, the life of the first waste liquid tank 101 is shortened, and the number of replacements is increased. Further, in normal use, the first waste liquid tank 101 is not frequently removed during the image recording operation and the maintenance / recovery operation. Therefore, the second waste tank 102 is preferably smaller than the first waste liquid tank 101. .

  Moreover, it is preferable that the second waste liquid tank 102 is provided with an absorbing member immediately below or around the discharge of the waste liquid. Further, when the ink is a fast-drying pigment ink or the like, the ink may dry and accumulate like a mountain, and the ink absorption efficiency of the absorbing member also decreases, so the second waste liquid tank 102 is the first waste liquid tank 101. It is preferable that it is a substantially sealed structure similarly to the above. However, when using dye ink or ink that is difficult to deposit, the volume of the open system is expected to be reduced due to drying of the ink itself, so the second waste tank 102 can be further reduced in size. The life of the waste liquid tank 101 can be increased by increasing the volume thereof.

  Thus, when the first waste liquid tank is attached, the waste liquid discharge path is set to the first waste liquid tank side, the waste liquid discharge path to the second waste liquid tank side is shut off, and the first waste liquid tank is removed. The first waste liquid tank is removed during the image recording operation and the maintenance recovery operation by providing a discharge passage switching means for blocking the waste liquid discharge path to the first waste liquid tank side with the waste liquid discharge path as the second waste liquid tank side. Even in such a case, the operation can be continued without contaminating the image forming apparatus with waste liquid.

  As a result, when the first waste liquid tank is removed in the middle of the waste liquid discharge operation, the waste liquid discharge operation is interrupted, that is, no negative pressure is formed in the recording head, and the apparatus remains in this state for a long time. If the ink is allowed to stand and the ink drips from the recording head, it is possible to eliminate the possibility that the ejection failure or the ejection failure of the recording head may occur.

Next, a waste liquid discharge path switching mechanism according to a second embodiment of the present invention will be described with reference to FIGS.
Here, a single tube 310 connected to the suction pump 220 is branched into two tubes 311, 312, and an electromagnetic valve (open / close valve) 301 is provided between the branch 313 and the first waste liquid tank 101. An electromagnetic valve (open / close valve) 302 is provided between the branch portion 313 and the second waste liquid tank 102. These electromagnetic valves 301 and 203 constitute waste liquid discharge path switching means. These solenoid valves 301 and 302 are switched and driven (open / close driven) by the switching drive control unit 400 in accordance with the detection result of the waste liquid tank detecting means 306 that detects whether or not the first waste liquid tank 101 is attached.

  With this configuration, when the waste liquid tank detecting means 306 detects that the first waste liquid tank 101 is mounted, the electromagnetic valve 301 is opened as shown in FIG. 311, and the solenoid valve 302 is closed so that the tube 310 and the tube 312 are shut off, so that the waste liquid discharge path downstream from the suction pump 220 is connected to the first waste liquid tank 101 side. Thus, the second waste liquid tank 102 side is shut off, and the waste liquid is discharged to the first waste liquid tank 101.

  When the waste liquid tank detecting means 306 detects that the first waste liquid tank 101 has been removed, the solenoid valve 301 is closed as shown in FIG. Since the valve 302 is opened and driven and controlled so that the tube 310 and the tube 312 communicate with each other, the waste liquid discharge path downstream from the suction pump 220 is on the second waste liquid tank 102 side. The first waste liquid tank 101 side is shut off, and the waste liquid is discharged to the second waste liquid tank 102.

  Thus, as in the first embodiment, even if the first waste liquid tank is removed during the image recording operation and the maintenance recovery operation, various operations can be completed without causing the image forming apparatus to be contaminated with the waste liquid. it can.

Next, a waste liquid discharge path switching mechanism according to a third embodiment of the present invention will be described with reference to FIGS.
Here, in place of the three-way solenoid valve 300 in the first embodiment, a flow path switching valve 340 is provided as waste liquid discharge path switching means. The flow path switching valve 340 divides the inside of the cylinder 341 into two chambers 343 and 344 by a piston 342 slidably fitted in the cylinder 341, connects the tube 311 to the chamber 343 side, and connects the tube 312 to the tube 312 side. 312 is connected and the tube 310 is connected to the center. Then, the end 345a of the piston rod 345 connected to the piston 342 is disposed at a position where it can contact the first waste liquid tank 101, and the piston 342 is biased toward the chamber 343 between the end 345a and the cylinder 341. A spring 346 as an elastic member is interposed.

  With this configuration, when the first waste liquid tank 101 is mounted, the piston 342 of the flow path switching valve 340 resists the biasing force of the spring 346 in the first waste liquid tank 101 as shown in FIG. Since it is pushed and moved to the chamber 344 side, the tube 310 and the tube 311 are communicated with each other through the chamber 343 and the tube 310 and the tube 312 are blocked, so the waste liquid discharge path downstream of the suction pump 220 is It becomes the first waste liquid tank 101 side, the second waste liquid tank 102 side is shut off, and the waste liquid is discharged to the first waste liquid tank 101.

  When the first waste liquid tank 101 is removed, as shown in FIG. 13, the piston 342 of the flow path switching valve 340 is moved to the chamber 343 side by the urging force of the spring 346, and the space between the tube 310 and the tube 311 is reduced. Since the tube 310 and the tube 312 communicate with each other through the chamber 344, the waste liquid discharge path downstream from the suction pump 220 is the second waste liquid tank 102 side, the first waste liquid tank 101 side is blocked, and the waste liquid is 2 It is discharged to the waste liquid tank 102.

  Thus, as in the first embodiment, even if the first waste liquid tank is removed during the image recording operation and the maintenance recovery operation, various operations can be completed without causing the image forming apparatus to be contaminated with the waste liquid. it can.

  In addition, since the flow path switching valve 340 mechanically switches the waste liquid discharge path in conjunction with the attachment / detachment of the first waste liquid tank 101, the presence / absence detection of the first waste liquid tank 101, the electromagnetic valve, and the like are not required, and the cost can be reduced. .

Next, a waste liquid discharge path switching mechanism according to a fourth embodiment of the present invention will be described with reference to FIGS.
Here, in the second embodiment, instead of the solenoid valves 301 and 302, the tube 311 between the branch part 313 and the first waste liquid tank 101 and the tube 312 between the branch part 313 and the second waste liquid tank 102 are provided. A discharge path switching mechanism 350 that blocks the discharge path by crushing in the middle is provided.

  The discharge path switching mechanism 350 includes a first arm 351 that crushes the tube 311 and a second arm 342 that crushes the tube 312. The first and second arms 351 and 352 are respectively connected to the support shafts 353 and 354. And is swingably supported. The first arm 351 and the second arm 352 are coupled to each other by a link member 355, and the second arm 352 crushes the tube 312 between the second arm 352 and the fixed portion, and the first arm A spring 356 for biasing the tube 311 to a position where the tube 311 is not crushed is interposed. The first arm 351 is disposed at a position that is pushed when the first waste liquid tank 101 is mounted and swings in a direction away from the tube 311.

  With this configuration, when the first waste liquid tank 101 is mounted, the first arm 351 of the discharge path switching mechanism 350 is pushed into the first waste liquid tank 101 and separated from the tube 311 as shown in FIG. As a result, the tube 310 is opened, and the first arm 351 is swung to a position where the second arm 352 crushes the tube 312 through the link member 355, thereby blocking the tube 312. The waste liquid discharge path downstream of the suction pump 220 is on the first waste liquid tank 101 side, the second waste liquid tank 102 side is shut off, and the waste liquid is discharged to the first waste liquid tank 101.

  Further, when the first waste liquid tank 101 is removed, as shown in FIG. 15, the first arm 351 of the discharge path switching mechanism 350 by the first waste liquid tank 101 is released and the first arm is released by the biasing force of the spring 356. When the tube 311 is swung to a position where the tube 311 is crushed, the tube 311 is cut off, and the second arm 352 is also swung to a position away from the tube 312 by the biasing force of the spring 356, thereby Therefore, the waste liquid discharge path downstream of the suction pump 220 is on the second waste liquid tank 102 side, the first waste liquid tank 101 side is shut off, and the waste liquid is discharged to the second waste liquid tank 102.

  Thus, as in the first embodiment, even if the first waste liquid tank is removed during the image recording operation and the maintenance recovery operation, various operations can be completed without causing the image forming apparatus to be contaminated with the waste liquid. it can.

  Further, since the discharge path switching mechanism 350 mechanically switches the waste liquid discharge path in conjunction with the attachment / detachment of the first waste liquid tank 101, the presence / absence detection of the first waste liquid tank 101, the electromagnetic valve, etc. are not required, and the cost can be reduced. .

  The image forming apparatus according to the present invention can be applied to a facsimile machine, a copying machine, a printer / fax / copier multifunction machine, etc., in addition to an inkjet printer. Furthermore, the present invention can also be applied to an image forming apparatus that discharges a liquid (recording liquid) other than ink, such as a resist or a DNA sample in the medical field.

33 Carriage 34, 34a, 34b Recording head (liquid ejection head)
35 Subtank 81 Maintenance / recovery mechanism 82a Suction and moisture retention cap 82b Moisture retention cap 83 Wiper member 84 Empty discharge receptacle 101 First waste liquid tank 102 Second waste liquid tank 219 Suction tube 220 Suction pumps 310, 311, 312 Tube 313 Branch portion 300 Three-way Solenoid valve 301, 302 Solenoid valve 340 Flow path switching valve 350 Discharge path switching mechanism

Claims (6)

A recording head having nozzles for discharging ink droplets;
A cap for capping the nozzle surface of the recording head;
Suction means for forming a negative pressure in the space sealed with the cap;
A first waste liquid tank for storing ink waste liquid;
A second waste liquid tank for storing ink waste liquid;
A waste liquid discharge path through the suction means and the first and second waste liquid tanks;
When the first waste liquid tank is attached, the waste liquid discharge path to the first waste liquid tank side is cut off from the waste liquid discharge path to the second waste liquid tank side,
A discharge path switching means for setting the waste liquid discharge path to the second waste liquid tank side and shutting off the waste liquid discharge path to the first waste liquid tank side when the first waste liquid tank is removed. An image forming apparatus.   The waste liquid discharge path has a branch portion branched into the first waste liquid tank side and the second waste liquid tank side, and the discharge path switching means is an electromagnetic valve provided in the branch portion. The image forming apparatus according to claim 1.   The waste liquid discharge path has a branch portion branched to the first waste liquid tank side and the second waste liquid tank side, and the discharge path switching means is between the branch portion and the first waste liquid tank and the branch portion. The image forming apparatus according to claim 1, wherein the image forming apparatus is an electromagnetic valve provided between the first waste liquid tank and the second waste liquid tank.   The image forming apparatus according to claim 1, wherein the discharge path switching unit switches the waste liquid discharge path in conjunction with an attachment / detachment operation of the first waste liquid tank.   The waste liquid discharge path is formed of an elastic member, and has a branch portion that branches into the first waste liquid tank side and the second waste liquid tank side, and the discharge path switching means includes the branch portion, the first waste liquid tank, 2. The image forming apparatus according to claim 1, further comprising a member that is provided between the first and second branch portions and between the second waste liquid tank and crushes the waste liquid discharge path.   6. The image forming apparatus according to claim 1, wherein at least one of the first waste liquid tank and the second waste liquid tank has a substantially hermetically sealed structure, and an absorbing member is provided therein.

Images