JP5212302B2 - Image recording device - Google Patents

Description

  The present invention relates to an image recording apparatus that forms an image or characters by discharging a liquid.

  2. Description of the Related Art Conventionally, there is an inkjet printer as an image recording apparatus that forms an image or characters on a recording medium by discharging a liquid. In such an ink jet printer, ink stored in a cartridge is supplied to a recording head, and minute ink droplets are ejected from nozzles of the recording head. If foreign matter is contained in the ink supplied to the recording head, foreign matter may be clogged in a small portion of the flow path cross section such as a nozzle, and ink may not be ejected. For this reason, a filter is disposed in the middle of the ink flow path from the cartridge to the recording head to capture foreign matter contained in the ink, thereby preventing ink non-ejection.

  However, as the cumulative amount of ink that has passed through the filter increases, the amount of foreign matter captured by the filter increases, resulting in clogging of the filter. When the filter is clogged, the flow path resistance of the filter portion increases, and the time until ink is supplied to the recording head after ink droplets are ejected increases. If an attempt is made to eject the next ink droplet before the ink is supplied to the recording head, the volume of the ejected ink droplet is reduced or no ink droplet is ejected at all.

  Therefore, in the droplet discharge device described in Patent Document 1, one end of the first ink flow path provided with the first filter is communicated with the ink tank, and the other end is communicated with the common flow path in the head. One end of the provided second ink flow path is connected to a connection portion between the first filter and the ink tank in the first ink flow path, and the other end is connected to a common flow path in the head. An ink flow rate pump is provided for circulating the ink in the flow path, the second ink flow path, and the common flow path in the head. Then, during maintenance of the droplet discharge device, the ink flow pump is driven so that the ink flows backward in the direction opposite to the direction in which the ink passes through the first filter in the first ink flow path when the head performs the discharge operation. Thus, the dust adhering to the ink tank side of the first filter is moved to the second filter. This prevents the flow path resistance from increasing in the first filter when the head performs an ejection operation.

JP 2008-238750 A (see FIG. 8)

  However, the droplet discharge device described in Patent Document 1 requires an ink flow rate pump for moving dust adhering to the first filter to the second filter, which may increase the size of the droplet discharge device. It also leads to cost increase.

  Therefore, an object of the present invention is to provide an image recording apparatus that can remove dust accumulated on a filter through which ink passes during an image recording operation without separately installing a pump in the image recording apparatus.

  An image recording apparatus according to a first aspect of the present invention includes a recording head that has a nozzle from which liquid is discharged, and that records an image on the recording medium by discharging the liquid from the nozzle toward the recording medium, and the recording A liquid tank for storing a liquid to be supplied to the head; a first flow path for communicating the recording head and the liquid tank; a first filter provided in the middle of the first flow path; and the first flow path. The second flow for communicating the first branch portion provided on the liquid tank side with respect to the first filter and the second branch portion provided on the recording head side with respect to the first filter of the first flow path. A second filter provided in the middle of the second flow path, the liquid tank, or a third branch section provided closer to the liquid tank than the first branch section of the first flow path. , The second branch of the first flow path and the first flow A third flow path that communicates with a fourth branch portion provided between the filter and a liquid that has flowed out of the liquid tank through only the first flow path to reach the recording head; A first passage path through which liquid passes through the first filter from a first surface of the first filter on the liquid tank side toward a second surface of the first filter on the recording head side; and the liquid tank After the liquid flowing out from the first flow path passes through the third flow path, it passes through the portion of the first flow path where the first filter is provided, and then passes through the second flow path to reach the recording head. A liquid passes through the first filter of the first flow path from the second surface toward the first surface and then passes through the second filter of the second flow path. Switching means for switching to the second passage route; Control means for controlling the switching means, and the control means controls the switching means when the liquid is ejected from the recording head toward the recording medium and an image is recorded. When the liquid is discharged from the recording head to a position other than the recording medium, the switching means is controlled to switch to the second passage path, and the foreign matter accumulated on the first filter. Is moved to the second filter. Here, the liquid is discharged from the recording head even if the recording head drives the recording head to discharge the liquid, and the liquid is forcibly discharged from the recording head by driving a component other than the recording head. Something to be included is also included.

  In general, ink jet printers have dust or bubbles near the nozzles, or ink that has increased in viscosity due to evaporation of moisture from the nozzles. Failure to do so may occur. In order to solve these problems, a recovery operation is performed in which dust, bubbles, or ink with increased viscosity is discharged by ejecting ink to other than the recording medium. According to the present invention, when the liquid is discharged from the recording head toward the recording medium, the liquid passes through the second passage path through which the liquid passes when the liquid is discharged from the recording head toward a position other than the recording medium. Since the liquid that has passed through the first filter in the direction opposite to the direction of passing through the first filter in the first passage path through which the ink passes passes through the second filter, at the same time as the liquid is discharged from the recording head in the recovery operation. The foreign matter accumulated on the first filter can be moved to the second filter.

  According to a second aspect of the present invention, there is provided an image recording apparatus having a nozzle from which a liquid is discharged, and recording the image on the recording medium by discharging the liquid from the nozzle toward the recording medium, and the recording A liquid tank for storing a liquid to be supplied to the head; a first flow path for communicating the recording head and the liquid tank; a first filter provided in the middle of the first flow path; and the first flow path. The second flow for communicating the first branch portion provided on the liquid tank side with respect to the first filter and the second branch portion provided on the recording head side with respect to the first filter of the first flow path. A path, a second filter provided in the middle of the second flow path, and a path through which the liquid flowing out from the liquid tank passes only through the first flow path to reach the recording head, The first filter is connected to the first filter. A first passage that passes from the first surface on the body tank side toward the second surface on the recording head side of the first filter, and the liquid that has flowed out of the liquid tank and the first flow path A path through which the liquid passes through the two flow paths to the recording head, where the liquid passes through the first surface of the first filter of the first flow path in a direction parallel to the surface; A switching unit configured to switch the second passage of the second flow path passing through the second filter; and a control unit configured to control the switching unit, wherein the first branching unit includes the liquid tank from the first filter. When the liquid that has flowed out of the liquid tank passes through the second passage in the vicinity of the first filter in the first flow path on the side, the first surface of the first filter is set to the surface. Passed in parallel direction At a position where the liquid that has passed through the second filter flows into the second flow path, and the control means is configured to record an image when the liquid is ejected from the recording head toward the recording medium. Controls the switching means to switch to the first passage path, and when the liquid is discharged from the recording head toward a place other than the recording medium, the switching means is controlled to enter the second passage path. It is characterized in that the foreign matter accumulated on the first filter is moved to the second filter by switching. As in the first aspect of the invention, the liquid is discharged from the recording head because the recording head drives the recording head to discharge the liquid. It also includes those that forcibly discharge.

  According to the present invention, the liquid that has passed through the first filter in a direction parallel to the surface of the first filter in the second passage path through which the liquid passes when the liquid is discharged from the recording head toward a place other than the recording medium. However, since it passes through the second filter, in the recovery operation, the liquid is discharged from the recording head, and at the same time, the foreign matter accumulated on the first filter can be moved to the second filter.

  According to a third aspect of the present invention, there is provided the image recording apparatus according to the first or second aspect, wherein a cap that seals a space contacting the surface of the recording head on which the nozzle is formed, and a space sealed by the cap. A suction means for sucking the air inside, and when the liquid is discharged from the recording head to a medium other than the recording medium, the suction means sucks the liquid from the recording head together with the air in the space. The liquid is ejected from the recording head.

  According to this invention, the foreign matter deposited on the first filter can be moved to the second filter using the suction means for sucking the air in the space sealed with the cap. Furthermore, when the liquid in the recording head is sucked together with air by the suction means, the flow velocity of the liquid in the liquid flow path can be increased as compared with the case where the recording head is driven and the liquid is ejected. It is possible to move the foreign matter to the second filter more efficiently.

  According to a fourth aspect of the present invention, there is provided the image recording apparatus according to any one of the first to third aspects, wherein the flow rate measuring means for measuring the flow rate of the liquid per unit time passing through the first passage path and the measured flow rate are used. The apparatus further comprises resistance calculation means for calculating the flow path resistance of the first passage path, and the control means has the calculated flow path resistance equal to or greater than a predetermined value and the liquid from the recording head is other than the recording medium. When discharging toward the first position, the switching means is controlled to switch to the second passage path, and foreign matter accumulated in the first filter is moved to the second filter.

  According to the present invention, whether or not the control means switches to the second passage flow path when the liquid is discharged from the recording head toward a place other than the recording medium according to the flow path resistance of the first passage path. Therefore, the number of times of switching the switching means can be reduced, and as a whole, the time required for the operation in which the liquid is discharged from the recording head toward other than the recording medium can be shortened.

  In the image recording apparatus according to the present invention, when the liquid is discharged from the recording head toward a place other than the recording medium, the liquid is discharged from the recording head, and at the same time, the foreign matter accumulated in the first filter is removed from the second filter. Can be moved to.

1 is a schematic configuration diagram of an inkjet printer according to an embodiment. It is a conceptual diagram of a flow-path switching valve. FIG. 2 is a block diagram illustrating an electrical configuration of a printer. It is explanatory drawing regarding the flow of the ink of an ink supply system. It is a flowchart regarding switching of a flow path. It is explanatory drawing equivalent to FIG. 4 of a 1st modification. It is explanatory drawing equivalent to FIG. 4 of a 2nd modification. It is explanatory drawing equivalent to FIG. 4 of a 3rd modification. It is explanatory drawing equivalent to FIG. 4 of a 4th modification.

  Next, a preferred embodiment of the present invention will be described. In the present embodiment, the present invention is applied to an ink supply system of an ink jet printer that ejects ink toward a recording sheet and records an image or the like on the recording sheet as an image recording apparatus.

  FIG. 1 is a schematic configuration diagram of an ink jet printer according to the present embodiment. As shown in FIG. 1, the printer includes a recording head 1, an ink tank 2 (liquid tank), first flow paths 101a to 101c, a second flow path 102, a third flow path 103, and a flow path switching valve 5 (switching). Means), a suction device 50 and the like.

  The recording head 1 includes an actuator (not shown), an ink supply port, a pressure chamber, a nozzle, and the like. The actuator applies pressure to the ink supplied from the ink tank 2 through the ink supply port. Then, ink is ejected from the nozzle. This actuator can adopt a form such as an electromechanical transducer such as a piezo element or an electrothermal transducer such as a heating element having a heating resistor. The recording head 1 and the ink tank 2 communicate with each other via a first flow path 101, a second flow path 102, and a third flow path 103, which will be described later, and the ink ejected from the nozzles is transferred from the ink tank 2 to the recording head 1. To be supplied.

  The ink tank 2 communicates with one end of the first flow path 101a, and the other end of the first flow path 101a communicates with the flow path switching valve 5a. The first flow path 101b, the second flow path 102, and the third flow path 103 communicate with the flow path switching valves 5a and 5b, respectively. The first flow path 101b and the second flow path 102 are provided with a first filter 3 and a second filter 4, respectively. One end of the first flow path 101c is in communication with the flow path switching valve 5b, and the other end of the first flow path 101c is in communication with the recording head 1. The recording head 1 and the ink tank 2 communicate with each other through the first flow path 101, the second flow path 102, and the third flow path. Here, the flow path switching valve 5a corresponds to the first branching section and the third branching section, and the flow path switching valve 5b corresponds to the second branching section and the fourth branching section.

  The flow path switching valve 5 includes a rotating member 15. The rotating member 15 is rotatable and switches communication of a plurality of flow paths connected to the flow path switching valve 5 according to the position. Specifically, as shown in FIG. 2 (a), the rotation member 15 of the flow path switching valve 5a has a first position where the first flow path 101a and the first flow path 101b communicate with each other, and FIG. ), The first flow path 101a and the third flow path 103, and the first flow path 101b and the second flow path 102 can be switched to the second position. Similarly, as shown in FIG. 2A, the rotating member 15 of the flow path switching valve 5b is also shown in FIG. 2B, in a first position where the first flow path 101b and the first flow path 101c are communicated. As described above, the first flow path 101b and the third flow path 103, and the first flow path 101c and the second flow path 102 can be switched to the second position.

  The suction device 50 includes a cap 6, a waste liquid tank 7, a waste liquid flow path 8, a suction pump 9, a moving stage 10, and a stage moving motor 11. The cap 6 and the waste liquid tank 7 communicate with each other via the waste liquid flow path 8. The cap 6 is installed on the moving stage 10, and the cap 6 comes in contact with and separates from the nozzle surface on which the nozzles of the recording head 1 are formed when the moving stage 10 is moved by the stage moving motor 11. A suction pump 9 is provided in the middle of the waste liquid flow path 8. When the cap 6 comes into contact with the nozzle surface, the suction pump 9 sucks the air in the space in front of the capped nozzle surface. The ink in the recording head 1 is simultaneously sucked and poured into the waste liquid tank 7.

  Next, the control device 20 that controls the entire printer will be described with reference to FIG. The control device 20 includes a central processing unit (CPU), a ROM (Read Only Memory) storing various programs and data for controlling the overall operation of the printer, and data processed by the CPU. And a microcomputer including a RAM (Random Access Memory) or the like for temporarily storing them. Alternatively, the control device 20 may be a hardware device in which various circuits including an arithmetic circuit are combined.

  Further, the control device 20 includes a recording control unit 21 and a maintenance control unit 22. The recording control unit 21 controls the flow path switching valve 5, a transport motor 30 (not shown) that transports the recording paper, and the head driver 40 of the recording head 1 to record an image or the like on the recording paper. Specifically, the conveyance motor 30 is controlled to convey the recording paper to a position facing the nozzle surface of the recording head 1. Thereafter, the head driver 40 is controlled to drive the actuator, thereby ejecting ink from the nozzles onto the recording paper to record an image or the like on the recording paper. At this time, the flow path switching valve 5 is controlled in advance to switch the rotating member 15 of the flow path switching valve 5 to the first position.

  On the other hand, the maintenance control unit 22 controls the flow path switching valve 5, the stage moving motor 11, the suction pump 9, and the head driver 40 of the recording head 1 to perform the maintenance operation of the recording head 1. In general, ink jet printers have dust or bubbles near the nozzles, or ink that has increased in viscosity due to evaporation of moisture from the nozzles. Failure to do so may occur. As a maintenance operation for solving these problems, a flushing operation in which an actuator is driven to eject a large amount of ink from a nozzle and a purge operation in which the nozzle surface is capped and suctioned are performed. Also, when the ink tank 2 is replaced, a purge operation may be performed to supply ink from the ink tank 2 to the recording head 1.

  During the flushing operation, the cap moving motor 11 is controlled to move the cap 6 to the vicinity of the nozzle surface. At this time, the cap 6 and the nozzle surface may or may not be in contact. Thereafter, the head driver 40 is controlled to drive the actuator so that ink is ejected from the nozzle toward the cap. The ink discharged to the cap 6 is sucked by controlling the suction pump 9 to flow into the waste liquid tank 7. As a result, dust or bubbles remaining in the vicinity of the nozzle are discharged from the nozzle. The flushing operation is not limited to ejecting ink toward the cap 6, and the ink may be ejected toward an absorbent body such as a sponge. When an image or the like is not recorded on the recording paper, the recording head Any form may be used as long as the actuator is driven and ink is ejected to maintain 1.

  In the purge operation, the cap moving motor 11 is controlled to bring the cap 6 into contact with the nozzle surface. Thereafter, the suction pump 9 is controlled to suck the air in the space in front of the capped nozzle surface, thereby simultaneously sucking the ink in the recording head 1 and flowing the ink into the waste liquid tank 7. As a result, when the dust or bubbles remaining in the vicinity of the nozzle are discharged from the nozzle or the ink tank 2 is replaced, ink can be supplied from the ink tank 2 to the recording head 1.

  The flushing operation is automatically performed when a predetermined time has elapsed after the recording operation on the recording paper is completed or before the recording operation is started. The purge operation may be performed when a user presses a maintenance switch (not shown) or automatically when the ink tank 2 is replaced. During these maintenance operations, the control device 20 controls the flow path switching valve 5 in advance to switch the rotating member 15 of the flow path switching valve 5 to the second position.

  Next, the relationship between the flow path through which ink passes in the recording operation and the maintenance operation and the flow path switching valve 5 will be described. During the recording operation, the rotating member 15 of the flow path switching valve 5 is switched to the first position as shown in FIG. 1, and the ink discharged from the ink tank 2 along the flow of the arrow A is The first flow paths 101a, 101b, and 101c reach the recording head 1 (first passage path). On the other hand, during the maintenance operation, the rotary member 15 of the flow path switching valve 5 is switched to the second position as shown in FIG. 4 and comes out of the ink tank 2 along the flow of the arrow B. The ink reaches the recording head 1 through the first flow path 101a, the third flow path 103, the first flow path 101b, the second flow path 102, and the first flow path 101c (second passage path).

  Next, the control in the recording operation and the maintenance operation will be described with reference to the flowchart of FIG. The control device 20 stores the time when ink was ejected from the recording head 1 last time. Then, when image data is input to the control device 20 (S11, Yes), it is determined whether or not a predetermined time has elapsed since the previous ink ejection (S12). Here, when the predetermined time has elapsed (S12, Yes), foreign matter has settled in the ink in the vicinity of the nozzle, or the water content of the ink from the nozzle evaporates and the viscosity of the nozzle increases. Therefore, there is a possibility that the ink cannot be ejected normally. Therefore, the rotary member 15 of the flow path switching valve 5 is switched to the second position to communicate the second passage (S13), the cap 6 is moved to the vicinity of the nozzle surface of the recording head 1, and the head driver 40 is controlled. Then, the actuator is driven to perform a flushing operation for ejecting ink from the nozzles (S14). Thereafter, the rotation member 15 of the flow path switching valve 5 is switched to the first position to communicate the first passage path (S14), the conveyance motor 30 is controlled to convey the recording sheet to a position facing the nozzle surface, Ink is ejected from the recording head 1 to record an image on recording paper (S16). If the predetermined time has not elapsed since the previous ink discharge (S12, No), the rotating member 15 of the flow path switching valve 5 is switched to the first position without performing the flushing operation, and the first passage is performed. The route is communicated (S14), and an image is recorded (S16).

  On the other hand, when the purge switch is pushed (S17, Yes) when no image data is input (S11, No), the control device 20 switches the rotating member 15 of the flow path switching valve 5 to the second position. Then, the second passage route is communicated (S18). Thereafter, the stage moving motor 11 is driven to bring the cap 6 into contact with the nozzle surface of the recording head 1, and the suction pump 9 is controlled to suck the air in the front surface of the nozzle surface. A purge operation for sucking ink is performed (S19).

  Even if the purge switch is not pressed (S17, No), when the ink tank 2 is replaced, the recording head 1 may not be filled with ink. Therefore, it is necessary to fill the recording head 1 with ink. Therefore, when the ink tank 2 is replaced (S20, Yes), similarly to when the purge switch is pressed, the control device 20 switches the rotating member 15 of the flow path switching valve 5 to the second position. The two passage paths are communicated (S18), and then a purge operation is performed (S19). When the ink tank 2 is replaced, air may enter the first flow path 101a, and the air mixed in the flow path can be removed by performing a purge operation.

  In these maintenance operations such as the flushing operation and the purge operation, the direction in which the ink of the first filter 3 flows in the first passage path is opposite to the direction in which the ink of the first filter 3 flows in the second passage path. Further, the ink that has passed through the first filter 3 passes through the second filter 4 in the second passage path. Therefore, the dust accumulated on the first filter 3 can be moved to the second filter 4 by the ink that has passed through the second passage path during the maintenance operation.

  In general, an ink supply system of an ink jet printer is provided with a filter for capturing dust contained in ink in an ink flow path. However, as the integrated amount of ink passing through the filter increases, the ink is captured by the filter. As the amount of waste increases, the filter becomes clogged. When the filter is clogged, the flow path resistance of the filter portion is increased, and the time until ink is supplied to the recording head after the ink is ejected is increased. If ink is further ejected before ink is supplied to the recording head, the volume of the ejected ink may be reduced, or no ink may be ejected at all.

  However, in the present embodiment, during the maintenance operation, the ink passes through the second filter 4 after passing through the first filter from the direction opposite to the direction in which the ink passes during the recording operation. The accumulated dust can be moved to the second filter 4. Thereby, the first filter 3 through which ink passes during the recording operation can be kept in an unclogged state, and it is possible to prevent an insufficient supply of ink during the recording operation. Here, by moving the dust accumulated on the first filter 3 to the second filter 4, the second filter 4 through which ink passes during the maintenance operation may be clogged. As described above, it is an operation for removing dust and bubbles near the nozzles and supplying ink to the recording head 1, and has a higher ink flow rate and a larger amount of ink used than in the recording operation. Therefore, even if the second filter is somewhat clogged, the flow of the ink is not hindered by the flow path resistance of the second filter 4, and the maintenance operation is not hindered. In addition, when a predetermined amount of ink ejected from each nozzle is not ejected due to clogging of the filter during the recording operation, the quality of the image recorded on the recording paper deteriorates, but the maintenance operation However, even if the ink discharged from each nozzle is not ejected by a predetermined amount, it is sufficient that dust or bubbles can be removed, which is not a problem compared to the recording operation. That is, dust or the like of the first filter 3 is moved to the second filter 4 during the maintenance operation, and the second filter 4 is used only during the maintenance operation, so that the second filter 4 used during the recording operation is used. It can be said that this is the best method for preventing clogging of one filter 3.

  In addition, in an ink jet printer, when a maintenance operation is performed, an ink flow generated when an ink is ejected by driving an actuator that is generally performed in a flushing operation, or ink generated by a suction pump that is performed in a purge operation. In order to move the dust accumulated on the first filter 3 to the second filter 4 because the dust accumulated on the first filter 3 can be moved to the second filter 4 during the recording operation. There is no need to install a separate pump. That is, since a conventionally used pump or the like is used, the printer is not increased in size and the cost is not increased.

  Next, modified embodiments in which various changes are made to the present embodiment will be described. However, the same reference numerals are given to those having the same configuration as in the above embodiment, and the description thereof is omitted as appropriate. In the following drawings, the illustration of the suction device 50 is omitted for simplicity.

  In the first modification, as shown in FIG. 6, the ink tank 2 communicates with one end of the first flow path 101a, and the other end of the first flow path 101a communicates with the gate valve 12a. The first flow path 101b communicates with the gate valves 12a and 12b. A first filter 3 is provided in the first flow path 101b. Furthermore, one end of the first flow path 101 c communicates with the gate valve 12 b and the other end of the first flow path 101 c communicates with the recording head 1. Further, between the gate valve 12a of the first channel 101b and the first filter 3, one end of the second channel 102 communicates, and the other end of the second channel 102 communicates with the first channel 101c. ing. The second flow path 102 is provided with a second filter 4. One end of the third flow path 103 communicates with the first flow path 101a, and the other end of the third flow path 103 communicates between the first filter 3 and the gate valve 12b of the first flow path 101b. ing. The third flow path 103 is provided with a gate valve 12c. These gate valves 12 may be any valves as long as they switch between connecting or blocking two connected flow paths. Here, the portion where the first channel 101b and the second channel 102 are connected is the first branch portion, and the portion where the first channel 101c and the second channel 102 are connected is the second branch portion. The part where the first flow path 101a and the third flow path 103 are connected is the third branch part, and the part where the first flow path 101b and the second flow path 102 are connected is the fourth branch part. It hits.

  During the recording operation, the gate valves 12 a and 12 b communicate the first flow paths 101 a, 101 b and 101 c, and the gate valve 12 c blocks the third flow path 103. As a result, the ink discharged from the ink tank 2 passes through the first flow paths 101a, 101b, and 101c and reaches the recording head 1 (first passage path). On the other hand, during the maintenance operation, the gate valves 12a and 12b block the first flow paths 101a and 101b and the first flow paths 101b and 101c, respectively, and the gate valve 12c allows the third flow path 103 to communicate. As a result, the ink discharged from the ink tank 2 passes through the first flow path 101a, the third flow path 103, the first flow path 101b, the second flow path 102, and the first flow path 101c and reaches the recording head 1. (Second passage route).

  Here, if the channel resistance of the third channel 103 is larger than the channel resistance of the first channel 101b, the gate valve 12c is not necessary. In addition, when the flow path resistance of the second flow path 102 is smaller than the flow path resistance of the first flow path 101b, the second flow path 102 is further provided with a gate valve, and this is performed during the recording operation. The gate valve may block the second flow path 102 so that the ink does not flow into the second flow path 102.

  Also in the first modified embodiment, as in the present embodiment, during the maintenance operation, the ink passes through the second filter 4 after passing through the first filter from the direction opposite to the direction in which the ink passes during the recording operation. Therefore, the dust accumulated on the first filter 3 can be moved to the second filter 4. Thereby, it is possible to prevent the first filter 3 through which ink passes during the recording operation from being clogged.

  In the second modification, as shown in FIG. 7, the ink tank 2 communicates with one end of the first flow path 101a, and the other end of the first flow path 101a communicates with the flow path switching valve 5a. Further, the first flow path 101b and the third flow path 103 communicate with the flow path switching valve 5a. In addition, the first flow path 101b, the second flow path 102, and the first flow path 101c communicate with the flow path switching valve 5b, and the other end of the first flow path 101c communicates with the recording head 1. Yes. The first flow path 101b is provided with the first filter 3, and on the ink tank 2 side of the first filter 3, the second flow path 102 so that ink flows in a direction parallel to the surface of the first filter 3. And the third flow path 103 communicates with each other. Furthermore, a second filter 4 is provided in the second flow path. Here, the portion where the first filter 3 and the second flow path 102 are connected is the first branch portion, and the flow path switching valve 5b corresponds to the second branch portion.

  In the recording operation, the flow path switching valves 5a and 5b communicate the first flow paths 101a, 101b, and 101c. As a result, the ink discharged from the ink tank 2 passes through the first flow paths 101a, 101b, and 101c and reaches the recording head 1 (first passage path). On the other hand, during the maintenance operation, the flow path switching valves 5a and 5b cause the first flow path 101a and the third flow path 103 to communicate with each other, and the second flow path 102 and the first flow path 101c to communicate with each other. The ink passes through the first flow path 101a, the third flow path 103, the second flow path 102, and the first flow path 101c along the flow of the arrow and reaches the recording head 1 (second passage path).

  At this time, the ink that has flowed toward the first filter 3 may flow through the second flow path 102 without providing the third flow path 103 and the flow path switching valve 5a.

  In the second modification, since the ink passes through the second filter 4 after passing through the surface of the first filter in a direction orthogonal to the direction in which the ink passes during the maintenance operation during the maintenance operation, The dust accumulated on the first filter 3 can be moved to the second filter 4 by flowing in a direction parallel to the surface of the filter. Thereby, it is possible to prevent the first filter 3 through which ink passes during the recording operation from being clogged.

  In the third modification, as shown in FIG. 8, the ink tank 2 communicates with one end of the first flow path 101a, and the other end of the first flow path 101a communicates with the gate valve 12a. The first flow path 101b communicates with the gate valves 12a and 12b. A first filter 3 is provided in the first flow path 101b. Furthermore, one end of the first flow path 101 c communicates with the gate valve 12 b and the other end of the first flow path 101 c communicates with the recording head 1. Further, on the gate valve 12 a side of the first filter 3, the second flow path 102 and the third flow path 103 are communicated so that the ink flows in a direction orthogonal to the direction in which the ink passes through the first filter 3. The other end of the second channel 102 communicates with the first channel 101c, and the other end of the third channel 103 communicates with the first channel 101a. The second flow path 102 is provided with a second filter 4. The third flow path 103 is provided with a gate valve 12c. Here, the part where the first filter 3 and the second flow path 102 are connected is the first branch part, and the part where the first flow path 101c and the second flow path 102 are connected is the second branch part. .

  During the recording operation, the gate valves 12 a and 12 b communicate the first flow paths 101 a, 101 b and 101 c, and the gate valve 12 c blocks the third flow path 103. As a result, the ink discharged from the ink tank 2 passes through the first flow paths 101a, 101b, and 101c and reaches the recording head 1 (first passage path). On the other hand, during the maintenance operation, the gate valves 12a and 12b block the first flow paths 101a and 101b and the first flow paths 101b and 101c, respectively, and the gate valve 12c allows the third flow path 103 to communicate. As a result, the ink discharged from the ink tank 2 passes through the first flow path 101a, the third flow path 103, the first flow path 101b, the second flow path 102, and the first flow path 101c along the flow of the arrows. Then, the recording head 1 is reached (second passage route).

  Here, if the channel resistance of the third channel 103 is larger than the channel resistance of the first channel 101b, the gate valve 12c is not necessary. In addition, when the flow path resistance of the second flow path 102 is smaller than the flow path resistance of the first flow path 101b, the second flow path 102 is further provided with a gate valve, and this is performed during the recording operation. The gate valve may block the second flow path 102 so that the ink does not flow into the second flow path 102. Further, the ink that has flowed toward the first filter 3 may be allowed to flow in the second flow path 102 without providing the third flow path 103 and the gate valve 12a.

  In the third modified embodiment, similarly to the second modified embodiment, the second pass after the ink passes through the surface of the first filter in the direction perpendicular to the direction in which the ink passes during the recording operation. Since it passes through the filter 4, dust accumulated on the first filter 3 can be moved to the second filter 4 by flowing in a direction parallel to the surface of the filter. Thereby, it is possible to prevent the first filter 3 through which ink passes during the recording operation from being clogged.

  As shown in FIG. 9, the fourth variation is that the ink tank 2 communicates with one end of the first flow path 101a and the third flow path 103, and the other end of the first flow path 101a is a flow path switching valve. The other end of the third flow path 103 communicates with the flow path switching valve 5b. The first flow path 101b communicates with the flow path switching valves 5a and 5b. A first filter 3 is provided in the first flow path 101b. One end of the first flow path 101 c communicates with the flow path switching valve 5 b and the other end of the first flow path 101 c communicates with the recording head 1. Furthermore, one end of the second flow path 102 communicates with the flow path switching valve 5a, and the other end of the second flow path 102 communicates with the flow path switching valve 5b. The second flow path 102 is provided with a second filter 4. The third flow path 103 is provided with a gate valve 12c. Here, the flow path switching valve 5a is the first branch section, the flow path switching valve 5b is the second branch section, the fourth branch section, and the ink tank 2 is the third branch section.

  During the recording operation, the flow path switching valves 5 a and 5 b communicate the first flow paths 101 a, 101 b and 101 c, and the gate valve 12 c blocks the third flow path 103. As a result, the ink discharged from the ink tank 2 passes through the first flow paths 101a, 101b, and 101c and reaches the recording head 1 (first passage path). On the other hand, during the maintenance operation, the flow path switching valve 5a connects the first flow path 101b and the second flow path 102, and the flow path switching valve 5b is connected to the third flow path 103, the first flow path 101b, and the second flow path. The flow path 102 and the 1st flow path 101c are connected, respectively, and the gate valve 12c connects the 3rd flow path. As a result, the ink that has flowed out of the ink tank 2 passes through the third flow path 103, the first flow path 101b, the second flow path 102, and the first flow path 101c along the flow of the arrow to the recording head 1. (Second passage route)

  Also in the fourth modified embodiment, as in the present embodiment, during the maintenance operation, the ink passes through the second filter 4 after passing through the first filter from the direction opposite to the direction in which the ink passes during the recording operation. Therefore, the dust accumulated on the first filter 3 can be moved to the second filter 4. Thereby, it is possible to prevent the first filter 3 through which ink passes during the recording operation from being clogged.

  The third flow path 103 communicating with the ink tank 2 in the fourth embodiment can also be applied to the first to third modifications.

  In the above, the ink is sucked from the outside of the recording head 1 by the suction pump 9 during the purge operation. However, the present invention is not limited to this, and the first flow path 101a, 101b, 101c, the second flow path 102, the second flow path, and the like. A pump is provided in one of the three flow paths 103, and the pump sucks the ink in the ink tank 2 and sends the sucked ink to the recording head 1, thereby pushing out and discharging the ink from the recording head 1. You may do it.

  In the above, during the maintenance operation, the dust is accumulated in the first filter 3 by switching to the second passage route, but this is not limited to this, and during the maintenance operation, The ink may be discharged from the recording head 1 through the first passage path. For example, a flow rate measuring unit that measures a flow rate per unit time when ink passes through the first passage is provided, and the control device 20 determines the area of the first filter 3 and the first flow rate from the measured flow rate. The flow path resistance of the first passage path is calculated based on the cross-sectional area of the passage 101, the length of the first passage path, the viscosity of the ink, and the environmental temperature. Only when the maintenance operation is performed when the calculated flow path resistance is equal to or greater than a predetermined value, the flow path through which the ink passes is switched to the second passage path. A known flow meter can be used as the flow rate measuring means. This flow rate measuring means may always measure the flow rate per unit time flowing through the first passage route, or may measure it every predetermined time.

  Depending on the area of the first filter 3, even if the first filter 3 is clogged to some extent, the supply of ink to the recording head 1 will not be in time for the recording operation. That is, in the maintenance operation, it is not always necessary to switch to the second passage route, and it is possible to switch to the second passage route only when the flow passage resistance of the first passage route becomes high. According to this, since the number of times of switching the flow path through which the ink passes to the second passage path can be reduced, the time for switching the flow path through which the ink passes can be shortened during the maintenance operation. Further, since the second passage route has a longer flow path length than the first passage route, it takes a long time for the ink flowing out from the ink tank 2 to reach the recording head 1, but during the maintenance operation, Since the ink flows through the first passage path, the maintenance operation time can be shortened.

DESCRIPTION OF SYMBOLS 1 Recording head 2 Ink tank 3 1st filter 4 2nd filter 5 Flow path switching valve 6 Cap 9 Suction pump 12 Gate valve 101 1st flow path 102 2nd flow path 103 3rd flow path

Claims (4)

A recording head having a nozzle from which liquid is discharged, and recording an image on the recording medium by discharging the liquid from the nozzle toward the recording medium;
A liquid tank for storing liquid to be supplied to the recording head;
A first flow path for communicating the recording head and the liquid tank;
A first filter provided in the middle of the first flow path;
A first branch portion provided on the liquid tank side from the first filter of the first flow path, and a second branch portion provided on the recording head side from the first filter of the first flow path. A second flow path for communication;
A second filter provided in the middle of the second flow path;
The liquid tank, or a third branch portion provided closer to the liquid tank than the first branch portion of the first flow path, and the second branch section and the first filter of the first flow path. A third flow path for communicating with a fourth branch portion provided therebetween;
The liquid flowing out from the liquid tank passes through only the first flow path and reaches the recording head, and the liquid passes through the first filter from the first surface of the first filter on the liquid tank side. A first passage path that passes toward the second surface of the first filter on the recording head side, and the liquid that has flowed out of the liquid tank passes through the third passage, and then the first passage. A path that passes through the portion where the first filter is provided and then passes through the second flow path to reach the recording head, and the liquid passes through the first filter in the first flow path to the second filter. Switching means for switching from a surface to the first surface and then switching to a second passage route passing through the second filter of the second flow path;
Control means for controlling the switching means,
The control means includes
When the liquid is ejected from the recording head toward the recording medium and an image is recorded, the switching unit is controlled to switch to the first passage path,
When the liquid is discharged from the recording head to a position other than the recording medium, the switching unit is controlled to switch to the second passage path, and the foreign matter accumulated on the first filter is removed from the second filter. An image recording apparatus which is moved to a filter. A recording head having a nozzle from which liquid is discharged, and recording an image on the recording medium by discharging the liquid from the nozzle toward the recording medium;
A liquid tank for storing liquid to be supplied to the recording head;
A first flow path for communicating the recording head and the liquid tank;
A first filter provided in the middle of the first flow path;
A first branch portion provided on the liquid tank side from the first filter of the first flow path, and a second branch portion provided on the recording head side from the first filter of the first flow path. A second flow path for communication;
A second filter provided in the middle of the second flow path;
The liquid flowing out from the liquid tank passes through only the first flow path and reaches the recording head, and the liquid passes through the first filter from the first surface of the first filter on the liquid tank side. A first passage path that passes toward the second surface of the first filter on the recording head side, and the liquid that has flowed out of the liquid tank passes through the first flow path and the second flow path. A path to the recording head, in which the liquid passes through the first surface of the first filter of the first flow path in a direction parallel to the surface, and then the second flow path of the second flow path. Switching means for switching between the second passage route passing through the filter;
Control means for controlling the switching means,
The first branch part is
In the vicinity of the first filter in the first flow path on the liquid tank side from the first filter, when the liquid flowing out from the liquid tank passes through the second passage, the first filter The liquid that has passed through the second filter after passing through the first surface in a direction parallel to the surface is provided at a position where the liquid flows into the second flow path,
The control means includes
When the liquid is ejected from the recording head toward the recording medium and an image is recorded, the switching unit is controlled to switch to the first passage path,
When the liquid is discharged from the recording head to a position other than the recording medium, the switching unit is controlled to switch to the second passage path, and the foreign matter accumulated on the first filter is removed from the second filter. An image recording apparatus which is moved to a filter. A cap that seals a space in contact with a surface on which the nozzle of the recording head is formed;
A suction means for sucking air in the space sealed with the cap;
When the liquid is discharged from the recording head to a medium other than the recording medium, the suction unit sucks the liquid from the recording head together with the air in the space, and discharges the liquid from the recording head. The image recording apparatus according to claim 1 or 2. Flow rate measuring means for measuring the flow rate of the liquid per unit time passing through the first passage,
A resistance calculating means for calculating a flow path resistance of the first passage based on the measured flow rate;
The control means includes
When the calculated flow path resistance is equal to or greater than a predetermined value and the liquid is discharged from the recording head toward a position other than the recording medium, the switching unit is controlled to enter the second passage path. The image recording apparatus according to claim 1, wherein the foreign matter accumulated in the first filter is switched to move to the second filter.

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