JP5510313B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus that records an image on a sheet by ejecting ink from nozzles of a recording head, and more particularly to an ink jet recording apparatus having a flushing function for recovering or maintaining ink ejection performance of a recording head.

  In an ink jet recording apparatus, so-called flushing that ejects ink from all nozzles is performed at a predetermined timing in order to maintain good ink ejection performance of the nozzles of the recording head. A flushing position is determined at a position outside the image recording area, and an ink receiving portion is provided on the platen corresponding to the flushing position. When the recording head is disposed at the flushing position, ink is ejected from the nozzle, and the ejected ink is received by the ink receiving portion. An ink tank for storing ink is provided below the ink receiving portion. The ink received by the ink receiving part flows down to the ink tank through the guide hole provided at the bottom of the ink receiving part, and is stored in the ink tank.

  When the ink tank is full of ink, the ink overflows and the ink leaks to the outside. As means for preventing such ink leakage, the conventional ink jet recording apparatus is provided with a function of integrating the amount of ink ejected from the recording head and outputting an alarm when the ink amount exceeds a reference value. Yes. Further, in Patent Document 1, the reference value is increased as the usage time of the apparatus increases, the changed reference value is compared with the integrated ink amount, and an alarm is issued when the ink amount exceeds the reference value. A recording apparatus for outputting is disclosed.

JP 2004-136550 A

  However, in the conventional recording apparatus described in Patent Document 1 and the like, the amount of ink ejected from the recording head is calculated based on the count value of the number of ink ejections. Therefore, when highly viscous ink adheres to the nozzles of the recording head or when the nozzles themselves are clogged, the ink may not be ejected even if the ink ejection operation is actually performed. For this reason, the ink amount calculated based on the count value is larger than the ink amount actually ejected. For this reason, in the conventional method for determining the overflow of the ink tank based on the ink amount calculated based on the count value, the ink exceeds the reference amount even when a sufficient storage capacity remains in the ink tank. There is a problem that a warning indicating that the ink tank is to be replaced or a message to replace the ink tank is output.

  The present invention has been made in view of the above problems, and an object thereof is to provide a mechanism that can accurately determine that ink of a reference value or more has been stored in an ink tank.

(1) The present invention is configured as an ink jet recording apparatus including a platen, a recording head, a carriage, an ink receiving portion, and an ink tank. The platen supports the recording medium transported in the first direction. The recording head is disposed above the platen and is configured to be able to eject ink droplets from a nozzle row composed of a plurality of nozzle holes. The carriage supports the recording head so as to be able to reciprocate in the second direction along the platen and perpendicular to the first direction. The ink receiving portion is provided outside the support area of the recording medium in the platen. The ink receiving portion has a first opening on the upper surface through which ink droplets ejected from the recording head enter during flushing to restore the ink ejection performance of the recording head. The ink tank is provided below the ink receiving portion. The ink tank is filled with the first liquid absorbing member. The ink receiving portion has a first guide path, a second opening, and a second guide path. The first guide path guides the ink ejected from the recording head to the first opening to the ink tank. The second opening is provided at a position separated from the first opening on the upper surface of the ink receiving portion. The second guide path is filled with a second liquid absorbing member capable of sucking up ink held by the first liquid absorbing member to the second opening.

  In this configuration, when flushing is performed, ink flows into the ink tank through the first opening and the first guide path. The ink that has flowed in is absorbed by the first liquid absorbing member. When the amount of ink flowing into the ink tank increases and the amount of ink held in the upper layer portion of the first liquid absorbing member increases, the weight of the ink wins against the holding force for holding the ink in the upper layer portion. The ink absorption range by the first liquid absorbing member gradually moves to the lower layer while expanding downward. On the other hand, when a certain amount of ink is absorbed by the first liquid absorbing member, the ink held by the first liquid absorbing member is gradually sucked up through the second liquid absorbing member of the second guide path by capillary action. Then, when the first liquid absorbing member is in a state where ink of a reference value or more is held, the sucked ink reaches the upper exposed surface of the second liquid absorbing member. At this time, the same color as the ink appears on the upper exposed surface which was the same color as the second liquid absorbing member. Thus, the user confirms the ink color appearing on the upper exposed surface of the second liquid absorbing member from the second opening, or causes the ink tank to detect the color density of the upper exposed surface by a sensor or the like, thereby causing the ink tank to exceed the reference value. It is possible to accurately determine that the ink has been stored.

(2) The inkjet recording apparatus of the present invention further includes a sensor provided on the carriage and a control unit. The sensor outputs a first detection signal corresponding to a change in color density of the upper exposed surface of the second liquid absorbing member that appears in the second opening. The control unit determines an ink storage state in the ink tank based on the first detection signal output from the sensor.

  Thereby, it is automatically determined by the control unit that ink of a reference value or more has been stored in the ink tank. A specific example of the sensor is a reflective type that includes a light emitting element and a light receiving element, and outputs a first detection signal by receiving the reflected light emitted from the light emitting element and reflected by the detection target by the light receiving element. An optical sensor is conceivable.

(3) The sensor is a reflective optical sensor. This sensor is also for detecting the presence or absence of a recording medium on the platen, and outputs a second detection signal corresponding to the presence or absence of the recording medium on the platen. The control unit determines whether a recording medium exists on the platen based on the second detection signal from the sensor.

  Thereby, since the sensor is used for each of the two determination functions (determination of the storage state and determination of the presence of the recording medium) that the control unit has, the number of installed sensors can be reduced.

(4) The upper exposed surface of the second liquid absorbing member coincides with a support position of the recording medium by the platen.

  A reflective optical sensor includes a light emitting element and a light receiving element, and the focal distance (distance to the detection target) and the emission angle of the light emitting element are received when light emitted from the light emitting element is reflected from the detection target. It is set to enter the element. As described above, when the distance from the sensor to the upper surface of the platen matches the distance from the upper exposed surface, the use for detecting the color density of the upper exposed surface and the presence or absence of the recording medium on the platen are determined. When the sensor is used for the purpose of detection, each detection target can be accurately detected without changing the focal length of the sensor (the distance to the detection target).

(5) The first liquid absorbing member includes a first absorbing portion on the first guide path side and a second absorbing portion on the second guide path side. In this case, it is preferable that a partition plate having a communication hole on the bottom side of the ink tank is provided between the first absorbing portion and the second absorbing portion.

  The ink absorbed in the upper layer portion of the first absorption portion also moves in the lateral direction by capillary action. However, since there is the partition plate, the ink is prevented from moving directly from the upper layer portion of the first absorption portion to the upper layer portion of the second absorption portion. That is, the ink reaches the bottom of the first absorption part, then moves to the second absorption part through the communication hole on the bottom side, and the ink is gradually absorbed from the bottom to the entire second absorption part by capillary action. . Therefore, unless the first liquid absorbing member is filled with ink, the ink does not reach the second liquid absorbing member of the second guide path. That is, when the first liquid absorbing member is filled with ink, an ink color appears on the upper exposed surface of the second liquid absorbing member. This makes it possible to reliably determine that the first liquid absorbing member is filled with ink.

(6) The first liquid absorbing member includes a first absorbing portion on the first guide path side and a second absorbing portion on the second guide path side. In this case, either one of the first absorption unit and the second absorption unit is a coating that delays the inflow of ink from the first absorption unit to the second absorption unit on a side surface that forms a boundary surface of each absorption unit. It is preferable that the treatment is performed.

  Thereby, even if the ink absorbed by the upper layer part of the 1st absorption part also moves to a horizontal direction by a capillary phenomenon, it becomes difficult for an ink to flow into the upper layer part of a 2nd absorption part. As a result, the ink color is prevented from appearing on the upper exposed surface of the second liquid absorbing member before the ink exceeding the reference value is stored in the ink tank.

(7) The first liquid absorbing member includes a first absorbing portion on the first guide path side and a second absorbing portion on the second guide path side. In this case, it is preferable that a thin film sheet that delays the inflow of ink from the first absorption unit to the second absorption unit is provided at the boundary between the first absorption unit and the second absorption unit.

  Thereby, even if the ink absorbed by the upper layer part of the 1st absorption part also moves to a horizontal direction by a capillary phenomenon, it becomes difficult for an ink to flow into the upper layer part of a 2nd absorption part. As a result, the ink color is prevented from appearing on the upper exposed surface of the second liquid absorbing member before the ink exceeding the reference value is stored in the ink tank.

  According to the present invention, it is accurately determined that ink of a reference value or more has been stored in the ink tank. Thereby, it is possible to accurately notify the storage time of the ink that is equal to or greater than the reference value and the replacement time of the liquid absorbing member. As a result, the liquid absorbing member in the ink tank can be effectively used without waste.

FIG. 1 is a perspective view of a multifunction machine 10 as an example of an embodiment of the present invention. FIG. 2 is a longitudinal sectional view schematically showing the internal structure of the printer unit 11. FIG. 3 is a plan view schematically showing the peripheral mechanism of the recording unit 24. FIG. 4 is a cross-sectional view taken along the section line IV-IV in FIG. 3, and the structure of the ink tank 140 is shown in detail. FIG. 5 is a block diagram of the control unit 100 included in the multifunction machine 10. FIG. 6 is a flowchart illustrating a procedure of color density detection processing executed by the control unit 100. FIG. 7 is a schematic diagram for explaining the moving position of the recording unit 24 and the flushing timing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. The embodiment described below is merely an example of the present invention, and it is needless to say that the embodiment of the present invention can be changed as appropriate without departing from the gist of the present invention. In the following description, the vertical direction 7 is defined with reference to a state in which the multifunction machine 10 is installed (the state shown in FIG. 1), and the side where the opening 13 is provided is the front side (front side). 8 is defined, and a left-right direction 9 is defined when the multifunction machine 10 is viewed from the front side (front side).

  As shown in FIG. 1, the multifunction machine 10 is generally formed in a thin rectangular parallelepiped, and a printer unit 11 of an ink jet recording system is provided at the lower part. The multifunction machine 10 has various functions such as a facsimile function and a print function. The presence or absence of functions other than the print function is arbitrary. Therefore, in this embodiment, descriptions of functions other than the print function and components that realize the functions are omitted.

[Configuration of Printer Unit 11]
As shown in FIG. 2, the printer unit 11 picks up the recording paper from the tray 20 (see FIG. 2) on which recording paper of various sizes (an example of the recording medium of the present invention) can be placed. A feeding section 15 that feeds ink, an ink jet recording type recording section 24 that performs image recording using ink, and a conveyance path 65. The printer unit 11 includes a casing 14 (see FIG. 1) having an opening 13 formed on the front surface, and the tray 20 is provided so as to be able to be inserted and removed from the opening 13 in the front-rear direction 8. That is, the tray 20 can be attached to and removed from the multifunction machine 10. In the present embodiment, the recording unit 24 is described as recording a color image with four colors of ink, specifically, pigment-based black ink, and dye-based yellow, cyan, and magenta inks. .

[Feeding unit 15]
As shown in FIG. 2, the feeding unit 15 is provided above the tray 20 and below the recording unit 24. The feeding unit 15 includes a paper feed roller 25, a paper feed arm 26, and a drive transmission mechanism 27 in which a plurality of gears are engaged. The paper feed roller 25 is pivotally supported at the tip of the paper feed arm 26. The paper feed arm 26 rotates in the direction of an arrow 29 about a support shaft 28 provided at the base end thereof. As a result, the paper feed roller 25 can come into contact with the recording paper placed on the tray 20 and can be separated from the tray 20. The sheet feeding roller 25 is rotated by the driving force transmitted from the sheet feeding motor 112 (see FIG. 5) by the drive transmission mechanism 27. The paper feed roller 25 rotates while being in contact with the uppermost recording paper among the recording papers stacked on the tray 20, thereby removing the recording paper from the other recording paper on the lower side. Separated and fed to a curved path 65A described later.

[Conveyance path 65]
As shown in FIG. 2, a conveyance path 65 is formed in the printer unit 11 from the front end (rear end) of the tray 20 to the paper discharge holding unit 79 through the recording unit 24. The conveyance path 65 is divided into a curved path 65 </ b> A formed between the leading end of the tray 20 and the recording unit 24, and a paper discharge path 65 </ b> B formed between the recording unit 24 and the paper discharge holding unit 79. .

  The curved path 65 </ b> A is a curved path extending from the vicinity of the upper end of the separation inclined plate 22 provided in the tray 20 to the recording unit 24. The curved path 65 </ b> A is generally formed in an arc shape centering on the inside of the printer unit 11. The recording paper fed from the tray 20 travels along the curved path 65A along the conveyance direction (the direction indicated by the one-dot chain line in FIG. 2) in the first conveyance direction (the direction of the arrow attached to the one-dot chain line in FIG. (Corresponding to the first direction of the invention) and guided directly below the recording unit 24. The curved path 65A is defined by an outer guide member 18 and an inner guide member 19 that face each other with a predetermined interval. Each of the outer guide member 18 and the inner guide member 19 extends in a direction perpendicular to the paper surface in FIG. 2 (the left-right direction 9 in FIG. 1).

  The paper discharge path 65 </ b> B is a linear path extending from directly below the recording unit 24 to the paper discharge holding unit 79. The recording paper is guided through the paper discharge path 65B in the first transport direction. The paper discharge path 65B is formed by the recording unit 24 and the platen 42 facing each other at a predetermined interval at a location where the recording unit 24 is provided, and at a location where the recording unit 24 is not provided. The upper guide member 82 and the lower guide member 83 are opposed to each other at a predetermined interval.

  As shown in FIG. 2, a pair of conveying rollers 59 including a driving roller 60 and a pinch roller 61 are provided on the upstream side of the recording unit 24 in the first conveying direction. A pair of paper discharge rollers 62 including a driving roller 63 and a pinch roller 64 is provided on the downstream side of the recording unit 24 in the first conveyance direction. The recording sheet fed from the tray 20 by the feeding unit 15 is moved through the conveyance path 65 by the conveyance roller pair 59 and the discharge roller pair 62 that rotate by receiving the driving force of the conveyance motor 113 (see FIG. 5). It is transported in one transport direction.

[Recording unit 24]
As shown in FIG. 2, the recording unit 24 is disposed above the tray 20. Below the recording unit 24, a platen 42 for horizontally supporting the recording sheet conveyed in the first conveying direction is provided. That is, the recording unit 24 is disposed above the platen 42. A plurality of narrow and long ribs 43 (see FIG. 3) extending along the front-rear direction 8 are provided on the upper surface of the platen 42. For this reason, the recording paper conveyed to the platen 42 is horizontally supported at a position slightly lifted from the surface of the platen 42 by the upper ends of the plurality of ribs 43 (position indicated by a wavy line in FIG. 7A). . The platen 42 is a dark color having a lower reflectance than white recording paper or a white form 91 described later. The recording unit 24 includes an ink-jet recording type recording head 38 (an example of the recording head of the present invention) that ejects ink droplets of four colors (black, yellow, cyan, and magenta) to record an image on recording paper, and a recording head. And a carriage 37 (an example of the carriage of the present invention) that supports 38.

  As shown in FIG. 3, the recording head 38 has a nozzle row 39 including a plurality of nozzle holes on a nozzle surface 40 (see FIG. 2) facing the platen 42. The carriage 37 supports the recording head 38 with the nozzle surface 40 exposed to the paper discharge path 65B. The recording head 38 has four nozzle rows 39K, 39Y, 39C, and 39M corresponding to four colors of black, yellow, cyan, and magenta, respectively. Each nozzle row 39 is arranged from right to left with respect to the nozzle surface 40 in the order of black, yellow, cyan, and magenta. Each nozzle row 39 is arranged at a predetermined interval in the left-right direction 9. In the present embodiment, the intervals between the nozzle rows 39Y, 39C, and 39M are D1, whereas the interval between the nozzle row 39K and the nozzle row 39Y is set to D2, which is longer than D1.

  The carriage 37 is movably supported by two guide rails 30 and 31 provided in a frame (not shown) extending in the left-right direction 9 (corresponding to the second direction of the present invention). Specifically, the carriage 37 is supported so as to be able to reciprocate in the direction perpendicular to the first transport direction and along the upper surface of the platen 42, that is, in the left-right direction 9. As the carriage 37 moves, the recording head 38 supported by the carriage 37 also moves in the same direction.

  A reciprocating mechanism 44 is provided on the guide rail 31. The reciprocating mechanism 44 includes a driving pulley 45 provided at one end of the guide rail 31 in the left-right direction 9, a driven pulley 46 provided at the other end, a belt 47 wound between the pulleys, a guide A carriage motor 111 (see FIG. 5) is connected to the drive pulley below the rail 31. The carriage 37 is moved in the left-right direction 9 by the driving force of the carriage motor 111 of the reciprocating mechanism 44 being transmitted through the driving pulley 45 and the belt 47.

  The guide rail 31 is provided with an encoder strip 51 of a linear encoder 116 (see FIG. 5). The encoder strip 51 is formed in a band shape, and light transmitting portions and light shielding portions are alternately arranged at a predetermined pitch along a longitudinal direction extending in the left-right direction 9. The carriage 37 is provided with an optical sensor 35 that is a transmissive sensor. The optical sensor 35 is arranged corresponding to the encoder strip 51 and detects the pattern of the encoder strip 51 when the carriage 37 reciprocates. A detection signal of the optical sensor 35 is output to the control unit 100 as a pulse signal from a head control board (not shown) mounted on the carriage 37. Based on this pulse signal, the control unit 100 calculates the moving direction and speed of the carriage 37, and the constant speed control and acceleration / deceleration control during the reciprocating movement of the carriage 37 are accurately performed.

  The recording unit 24 is transported on the platen 42 by ejecting ink of each color supplied from an ink cartridge (not shown) from a nozzle hole in a reciprocating movement in the left-right direction 9 under movement control by the control unit 100. Land on the recording paper. As a result, an image is recorded on the recording paper conveyed through the conveyance path 65.

  As shown in FIG. 3, the carriage 37 includes a media sensor 86 (an example of the sensor of the present invention). The media sensor 86 is used for detecting the presence / absence of recording paper on the platen 42, and for detecting the color density of the exposed surface 91A (see FIG. 4) of the form 91 from the opening 138 as will be described later. Used. The media sensor 86 includes a light emitting element such as an LED and a light receiving element such as a phototransistor. The light emitting element can emit light downward.

  When the media sensor 86 is used as an application for detecting the presence or absence of a recording sheet on the platen 42, the light emitted from the light emitting element is applied to the recording sheet conveyed on the platen 42. When the recording paper is not conveyed up to the platen 42, the light is applied to the platen 42. The light applied to the recording paper or the platen 42 is reflected and enters the light receiving element. The light receiving element receives the reflected light and outputs an electrical signal (corresponding to the second detection signal of the present invention) corresponding to the amount of received light. As the carriage 37 is moved as described above, the media sensor 86 scans the platen 42. Then, the control unit 100 determines whether or not the recording sheet exists on the platen 42 based on the change in the value of the electric signal. Specifically, the reflectance of the upper surface of the platen 42 is lowered with respect to the recording paper, and when the electric signal is smaller than a predetermined threshold, it is determined that there is no recording paper on the platen 42, and the electric signal is If it is greater than the predetermined threshold, it is determined that there is a recording sheet on the platen 42. The operation when the media sensor 86 is used as an application for detecting the color density of the exposed surface 91A (see FIG. 4) will be described later.

[Purge mechanism 130]
As shown in FIG. 3, a purge mechanism 130 is provided on one side of the platen 42 in the left-right direction 9 (right side in FIG. 3). The purge mechanism 130 is disposed outside the recording paper support area of the platen 42, that is, outside the ink ejection area. Specifically, it is provided at the right end of the platen 42.

  The purge mechanism 130 performs an operation of sucking ink from the nozzle holes of the recording head 38 (also referred to as purge), and mainly includes caps 133 and 134 and a suction pump (not shown). The caps 133 and 134 are moved in a direction (up and down direction 7) in contact with and away from the nozzle surface 40 of the recording head 38 by a drive mechanism (not shown). In the present embodiment, the positions of the caps 133 and 134 that do not contact the recording head 38 are referred to as standby positions, and the positions of the caps 133 and 134 that can be in close contact with the recording head 38 are referred to as maintenance positions. That is, the caps 133 and 134 are arranged in the standby position or the maintenance position by being moved in the vertical direction 7 by the drive mechanism.

  When the carriage 37 is disposed above the purge mechanism 130 (position indicated by the wavy line in FIG. 3), the purge mechanism 130 moves from the standby position to the maintenance position. The caps 133 and 134 are in close contact with the nozzle surface 40 to cover the nozzle rows 39 with a sealed space. The cap 133 integrally covers the nozzle rows 39Y, 39C, and 39M that eject color inks of yellow, cyan, and magenta. The cap 134 integrally covers the nozzle row 39K that ejects black ink. The lip portion where each cap 133, 134 is in close contact with the nozzle surface 40 is made of an elastic member such as rubber, and is elastically deformed when each cap 133, 134 is pressed against the nozzle surface 40. By the elastic deformation of the lip portion, the lip portion and the nozzle surface 40 are brought into close contact with each other, and the internal spaces of the caps 133 and 134 become sealed spaces. When the suction pump is operated in this state, ink of each color is sucked into the caps 133 and 134 from the nozzle holes of the recording head 38 by the suction pressure. When ink of each color is sucked from the recording head 38, bubbles, dust, etc. generated in the recording head 38 are sucked into the caps 133 and 134 together with the ink.

[Waste ink tray 132 and ink tank 140]
As shown in FIG. 3, a waste ink tray 132 (an example of an ink receiving portion of the present invention) is provided on the other side of the platen 42 in the left-right direction 9 (left side in FIG. 3). The waste ink tray 132 is disposed outside the recording paper support area of the platen 42, that is, outside the ink ejection area. Specifically, it is provided at the left end of the platen 42.

  The waste ink tray 132 receives ink droplets ejected from the recording head 38 during maintenance. For example, when the above-described purging is performed, there is a possibility that inks of different colors are mixed into the nozzle row 39 or the ink meniscus in the nozzle holes becomes abnormal. In such a case, when ink droplets are ejected from all the nozzle rows 39 of the recording head 38, the mixed ink is discharged or the meniscus of each nozzle hole returns to a normal state. Such an ejection operation is an operation for recovering the ink ejection performance, and is called flushing. When flushing is performed, the recording head 38 is moved above the waste ink tray 132, and ink droplets are ejected from the nozzle row 39 of the recording head 38 toward the waste ink tray 132.

  The waste ink tray 132 is formed in a tray shape corresponding to the nozzle surface 40 of the recording head 38. Below the waste ink tray 132, an ink tank 140 (an example of the ink tank of the present invention) for storing the ink ejected to the waste ink tray 132 is provided. The upper surface of the waste ink tray 132 is provided with an opening 136 (an example of the first opening of the present invention), an opening 137 (an example of the ink tank of the present invention), and an opening 138 (an example of the second opening of the present invention). It has been. The opening 136 arranged on the rightmost side is a portion that receives black ink ejected from the nozzle row 39K. An opening 137 is disposed on the left side of the opening 136. The opening 137 is a portion that receives yellow, cyan, and magenta color inks. In the present embodiment, as shown in FIG. 3, the distance between the opening 136 and the opening 137 (center distance) is set to D2 which is the same as the distance between the nozzle row 39K and the nozzle row 39Y.

  In addition, an opening 138 is arranged at a position separated rearward from the left side of the opening 137. Specifically, the opening 138 is disposed at a position where light from the optical sensor 35 provided on the carriage 37 can be irradiated when the carriage 37 moves in the left-right direction 9. The opening 138 is a portion for exposing the ink stored in the ink tank 140 to the upper surface of the waste ink tray 132 when the ink is sucked as will be described later.

  As shown in FIG. 4, the ink tank 140 has a right ink chamber 141 and a left ink chamber 142 that are divided in the left-right direction. A partition wall 143 (an example of a partition plate of the present invention) is provided between the right ink chamber 141 and the left ink chamber 142. The right ink chamber 141 is provided with a foam 88 (an example of the first absorbent portion of the present invention) made of a nonwoven fabric, sponge, cotton, or the like that can absorb ink. The foam 88 is cut out at the upper right side so that the pigment-based black ink guided downward by a flow path 136A, which will be described later, flows down directly to the bottom of the right ink chamber 141. On the other hand, the upper part of the left portion of the form 88 is in contact with the lower end of a flow path 137A described later, and the dye-based color ink guided downward by the flow path 137A directly flows into the form 88. Yes.

  The left ink chamber 142 is provided with a foam 89 (an example of the second absorbent portion of the present invention) made of a nonwoven fabric, sponge, cotton, or the like that can absorb ink. The foam 89 is packed in the entire left ink chamber 142. The upper part of the foam 89 is in contact with the lower end of a flow path 138A described later.

  A communication hole 144 is formed at the lower end of the partition wall 143. Therefore, when the ink that has flowed into the right ink chamber 141 fills the form 88, it flows into the left ink chamber 142 from the communication hole 144. When the amount of ink flowing into the right ink chamber 141 increases, the ink is gradually sucked up from the lower part to the upper part of the foam 89 by capillary action.

  As shown in FIG. 4, the waste ink tray 132 is provided with three flow paths 136A, 137A, and 138A. The flow path 136 </ b> A (an example of the first guide path of the present invention) extends downward from the opening 136, and its lower end reaches an area where the foam 88 on the right upper side of the right ink chamber 141 does not exist. The black ink ejected to the opening 136 flows into the right ink chamber 141 of the ink tank 140 through the flow path 136A and is absorbed by the foam 88 at the bottom of the right ink chamber 141.

  The flow path 137A (an example of the first guide path of the present invention) extends downward from the opening 137, and the lower end thereof reaches the upper end of the foam 88 at the upper left side of the right ink chamber 141. The flow path 137A is filled with a foam 90 made of non-woven fabric, sponge, cotton or the like that can absorb ink. The color ink ejected to the opening 137 flows into the right ink chamber 141 of the ink tank 140 through the flow path 137A while being absorbed by the foam 90 in the flow path 137A, and is absorbed by the foam 88.

  The flow path 138A (an example of the second guide path of the present invention) extends downward from the opening 138, and the lower end thereof reaches the left ink chamber 142. The flow path 138A is filled with a white foam 91 (an example of the second liquid absorbing member of the present invention) made of a nonwoven fabric, sponge, cotton, or the like that can absorb ink. When the ink sucked up from the lower part to the upper part of the foam 89 in the left ink chamber 142 reaches the upper end of the foam 89, the ink is sucked up from the lower end part of the foam 91, and finally the exposed surface 91A on the upper part of the foam 91. Appears in When ink appears on the exposed surface 91A, the exposed surface 91A is dyed in ink color. That is, the color of the exposed surface 91 changes from white, which is the same color as the form 91, to the ink color, and the color density of the exposed surface 91A changes. The color density and the change in the color density are detected by a color density detection process performed by the control unit 100 described later.

  In the present embodiment, as shown in FIG. 7, the form 91 has a wavy line at the height position of the exposed surface 91 </ b> A and the support position of the recording paper supported by the ribs 43 of the platen 42 (FIG. 7A). The position shown in FIG. As a result, the focal length of the media sensor 86 becomes the same when the color density is detected and when the recording paper is detected, and both detections are performed accurately.

  Next, the configuration of the control unit 100 (an example of the control unit of the present invention) will be described with reference to FIG. As illustrated in FIG. 5, the control unit 100 mainly includes a CPU 101, a ROM 102, and a RAM 103. The CPU 101, the ROM 102, and the RAM 103 are connected to each other via a bus line. The control unit 100 is connected to the carriage motor 111, the paper feed motor 112, the transport motor 113, the linear encoder 116 that detects the position of the carriage 37, the optical sensor 35, and the recording paper on the platen 42 via the input / output port 105. And a media sensor 86 that detects the color density of an exposed surface 91A (see FIG. 4) described later.

  The CPU 101 controls each part connected to the input / output port 105 according to the data values stored in the ROM 102 and the RAM 103 and the control program, thereby controlling the movement of the carriage 37, the detection process of the recording paper in the platen 42, and the flushing. Control, color density detection processing described later shown in the flowchart of FIG. 7, and the like are performed. The ROM 102 is a non-rewritable memory that stores a control program executed by the multifunction machine 10. A program for executing the color density detection process is stored in the ROM 102. The RAM 103 is a rewritable volatile memory that temporarily stores various data necessary for the operation of the multifunction machine 10 and stores threshold data used in the above-described processes and controls.

  Hereinafter, the procedure of the color density detection process shown in the flowchart of FIG. 6 executed by the CPU 101 will be described with reference to FIG. 7, and the movement control and flushing operation of the carriage 37 will be described. FIG. 7 is a schematic diagram for explaining the moving position of the recording head 38 and the flushing timing. FIG. 7A shows a state in which the carriage 37 is moving toward the waste ink tray 132. (B) shows a state in which the media sensor 86 has reached the upper side of the opening 138, and (C) shows a state in which the carriage 37 has reached the left end portion of the platen 42. (D) Fig. 9 shows a state in which the nozzle row 39K has reached above the opening 136 and the nozzle row 39Y has reached above the opening 137, and (E) shows a state in which the nozzle row 39C has reached above the opening 137. (F) shows a state in which the nozzle row 39M has reached above the opening 137.

  When the multifunction machine 10 is in a standby state where it can accept an image recording instruction, the carriage 37 is disposed above the purge mechanism 130 (hereinafter referred to as “initial position”). When a recording instruction is input to the multifunction machine 10 (S11), the CPU 101 initializes flag settings in the RAM 103. Specifically, the waste liquid form flag indicating the ink storage state in the ink tank 140 is set to “0” (S12). When the waste liquid form flag is “0”, it means that the ink amount in the ink tank 140 is less than the reference value, and when the waste liquid form flag is “1”, the ink amount in the ink tank 140 is It means that it is less than the reference value.

  When the initialization of the flag setting in the RAM 103 is completed, the CPU 101 moves the carriage 37 at the initial position (S13). The carriage 37 is controlled at a constant speed after being accelerated from the initial position. Then, when the platen 42 approaches the other end, it is decelerated, temporarily stopped, and then controlled to move in the opposite direction. When the carriage 37 moves from the initial position, the optical sensor 35 (see FIG. 5) provided on the carriage 37 detects the pattern of the encoder strip 51 (see FIG. 3). The control unit 100 grasps the movement amount of the carriage 37 based on the number of pulse signals based on the detection of the optical sensor 35 and accurately grasps the movement position of the carriage 37 based on the initial position.

  Subsequently, the CPU 101 determines whether or not the carriage 37 has reached the color density detectable position (S14). Specifically, the CPU 101 determines whether the media sensor 86 has reached the upper side of the opening 138 as shown in FIG. 7B based on the amount of movement of the carriage 37 from the initial position. When it is determined that the carriage 37 has reached the color density detectable position, the CPU 101 starts detecting the color density of the exposed surface 91A of the form 91 (S15). Specifically, light is emitted from the light emitting element of the media sensor 86 to irradiate the exposed surface 91A of the form 91, and the reflected light reflected from the exposed surface 91A is received by the light receiving element. At this time, the numerical value of the electrical signal output from the media sensor 86 (hereinafter referred to as “sensor output value”) is stored in the RAM 103.

  Next, the CPU 101 compares the sensor output value stored in the RAM 103 with a predetermined threshold value to determine whether the sensor output value is less than the threshold value (S16). The threshold value is density value information for identifying that the color density of the exposed surface 91A has changed from white to ink. If it is determined that the sensor output value is less than the threshold value, it means that the exposed surface 91A has not yet reached the threshold density value, that is, the ink tank 140 does not store ink above the reference value. . If it is determined that the sensor output value is equal to or greater than the threshold value, it means that the exposed surface 91A has changed to an ink color, that is, ink equal to or greater than the reference value has been stored in the ink tank 140.

  If it is determined in step S16 that the sensor output value is equal to or greater than the threshold value, the waste liquid form flag is set to “1” (S17), and then the color density detection process ends (S18). In the color density detection process (S15) and the sensor output value comparison determination process (S16) by the CPU 101, the sensor output value exceeds a threshold value or the carriage 37 is out of the color density detectable position and the color density cannot be detected. The process is continued until the position (color density detection impossible position) is reached (S19). If the sensor output value is less than the threshold value and the carriage 37 has reached the color density non-detectable position, the color density detection process ends without setting the waste liquid form flag to “1” (S18).

  Next, the CPU 101 determines whether or not the carriage 37 has reached the reverse position (S20). When the carriage 37 reaches the reverse position shown in FIG. 7C, the carriage 37 is temporarily stopped and immediately starts moving in the opposite direction (S21).

  Next, the CPU 101 performs flushing while the carriage 37 is moving in the reverse direction (S22). Specifically, as shown in FIG. 7D, at the timing when the nozzle row 39K reaches above the opening 136 and the nozzle row 39Y reaches above the opening 137, each of the nozzle row 39K and the nozzle row 39Y. Ink is ejected from. The number of ink ejections is not limited to one, and may be performed a plurality of times. Note that if ink is ejected while the carriage 37 is moving, ink droplets fly in the moving direction. In actuality, the ink droplets are opened 136 in consideration of the moving speed and moving position of the carriage 37, the gap with the waste ink tray 132, and the like. , 137, ink is ejected at such a timing. Subsequently, as shown in FIG. 7E, ink is ejected from the nozzle row 39C at the timing when the nozzle row 39C reaches above the opening 137. Further, as shown in FIG. 7F, ink is ejected from the nozzle row 39M at the timing when the nozzle row 39M reaches above the opening 137.

  When the flushing is completed, the CPU 101 returns the carriage 37 to the initial position and then starts image recording. When starting the image recording, if the waste liquid form flag is set to “1” (S 23), the CPU 101 outputs a replacement display message for prompting replacement of the ink tank, and is shown in FIG. It displays on the display part which does not (S24). The exchange display message may be output before the image recording is started, or the image recording may be stopped when the waste liquid form flag is set to “1”.

[Operations and effects of the embodiment]
In the above-described embodiment, when flushing is performed, the ink flows into the right ink chamber 141 through the flow path 136A and the flow path 137A and is absorbed by the foam 88. However, since there is a partition wall 143 between the left ink chamber 142 and the right ink chamber 141, the ink that has flowed into the right ink chamber 141 does not immediately move to the left ink chamber 142, but gradually spreads downward and gradually moves to the lower layer. Move. When a certain amount of ink is absorbed by the foam 88, it moves to the left ink chamber 142 through the communication hole 144 of the partition wall 143, is absorbed by the bottom of the foam 89, and is gradually sucked upward by capillary action. Then, the ink that has reached the upper end of the form 89 is absorbed by the form 91 of the flow path 138A and further sucked up. When this ink reaches the exposed surface 91 </ b> A of the form 91, the same color as the ink appears on the exposed surface 91 </ b> A that was the same color as the form 91. When ink is sucked up to the exposed surface 91A, the ink tank 140 is in a state where ink of a reference value or more is stored. When the control unit 100 determines that the color density of the exposed surface 91 </ b> A has changed based on the electrical signal from the media sensor 86, the control unit 100 outputs a replacement display message for the ink tank 140. For this reason, the user can easily grasp that the ink exceeding the reference value has been stored in the ink tank 140 and the exact replacement timing of the forms 88 and 89.

  The form 91 is provided so that the height position of the exposed surface 91A coincides with the support position of the recording paper supported by the ribs 43 of the platen 42 (the position indicated by the wavy line in FIG. 7A). Therefore, the focal length of the media sensor 86 is the same when detecting the color density and when detecting the recording paper, and both detections are performed accurately.

  In the above-described embodiment, the partition wall 143 is provided between the left ink chamber 142 and the right ink chamber 141 of the ink tank 140, but instead of the partition wall 143, the boundary between the foam 88 and the foam 89 is provided. One side of the facing foam 88 may be coated. This coating process is a process in which the speed at which the ink flows from the foam 88 to the foam 89 is slower than the moving speed in the foam 88. For example, when the foam 88 is urethane foam, one side is heat-treated. It is conceivable that the composition is deformed so that the void appearing on one side becomes smaller. Further, a thin film sheet for preventing the inflow of ink may be provided on one side surface except the bottom of the foam 88. Even in such an embodiment, it is difficult for ink to flow from the upper layer portion of the foam 88 to the upper layer portion of the foam 89. As a result, the ink color is prevented from appearing on the exposed surface 91 </ b> A of the form 91 before the ink exceeding the reference value is stored in the ink tank 140.

  The ink tank 140 may have a configuration in which the partition wall 143 is not provided between the left ink chamber 142 and the right ink chamber 141 and the left ink chamber 142 and the right ink chamber 141 are not partitioned. In the first place, since the moving speed in the horizontal direction is slower than the moving speed of the ink in the vertically downward direction, it is possible to grasp the exact replacement timing of the foam without using the partitioning structure.

10: MFP 20: Tray 24: Recording unit 37: Carriage 38: Recording head 39: Nozzle array 40: Nozzle surface 86: Media sensors 88, 89, 90, 91: Form 130: Purge mechanism 132: Waste ink tray 136, 137, 138: Openings 136A, 137A, 138A: Flow path 140: Ink tank 143: Partition wall 144: Communication hole

Claims (6)

A platen that supports the recording medium conveyed in the first direction;
A recording head disposed above the platen and capable of ejecting ink droplets from a nozzle array comprising a plurality of nozzle holes;
A carriage that supports the recording head so as to reciprocate in a second direction along the platen and perpendicular to the first direction;
An ink receiving portion provided on an outer surface of a support area of the recording medium in the platen and having a first opening on an upper surface into which ink droplets ejected from the recording head enter during flushing to restore ink ejection performance of the recording head; ,
An ink tank provided below the ink receiving portion and filled with a first liquid absorbing member;
The ink receiver is
A first guide path for guiding ink ejected from the recording head to the first opening to the ink tank;
A second opening provided at a position separated from the first opening on the upper surface;
A second guide path filled with a second liquid absorbing member capable of sucking up ink held in the first liquid absorbing member to the second opening ,
A sensor that is provided in the carriage and outputs a first detection signal corresponding to a change in color density of the upper exposed surface of the second liquid absorbing member that appears in the second opening;
An ink jet recording apparatus, further comprising: a control unit that determines an ink storage state in the ink tank based on the first detection signal from the sensor. The sensor is a reflective optical sensor that outputs a second detection signal corresponding to the presence or absence of a recording medium in the platen,
The ink jet recording apparatus according to claim 1 , wherein the control unit determines whether or not a recording medium exists on the platen based on the second detection signal from the sensor. The inkjet recording apparatus according to claim 2 , wherein the upper exposed surface of the second liquid absorbing member coincides with a support position of the recording medium by the platen. The first liquid absorbing member has a first absorbing portion on the first guide path side and a second absorbing portion on the second guide path side,
The ink-jet recording apparatus according to any one of claims 1-3, which is provided between the partition plate the first absorption part and the second absorption part having a communicating hole on the bottom side of the ink tank. The first liquid absorbing member has a first absorbing portion on the first guide path side and a second absorbing portion on the second guide path side,
Either one of the first absorption unit and the second absorption unit is subjected to a coating process that delays the inflow of ink from the first absorption unit to the second absorption unit on a side surface that forms a boundary surface of each absorption unit. The inkjet recording apparatus according to any one of claims 1 to 3 . The first liquid absorbing member has a first absorbing portion on the first guide path side and a second absorbing portion on the second guide path side,
The thin film sheet which delays the inflow of the ink from the said 1st absorption part to the said 2nd absorption part in the boundary of the said 1st absorption part and the said 2nd absorption part is provided in any one of Claim 1 to 3 The ink jet recording apparatus described.

Images