JP5896880B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus that performs recording on a recording medium such as paper by ejecting ink from nozzles.

In general, an ink jet recording apparatus includes a plurality of recording heads having nozzles for ejecting ink, and a waste ink tray (waste liquid tray) that receives ink ejected from the plurality of recording heads (for example, a patent). Reference 1).
The ink received in the waste ink tray is sent to the waste ink tank through the ink discharge hole (ink discharge portion) of the waste ink tray and stored.

JP 2002-103649 A

  However, in the ink jet recording apparatus described in Patent Document 1, the ink received on the waste ink tray (waste liquid tray) is dried and the viscosity of the ink is increased, so that the ink is deposited and solidified on the waste ink tray. There is a problem. In addition, when the ink is accumulated near the ink discharge hole of the waste ink tray and solidified, the ink discharge hole may be clogged with the accumulated and solidified ink.

  The present invention provides an ink jet recording apparatus that includes a plurality of recording heads and a waste liquid tray that receives ink discharged from the plurality of recording heads, and that can reduce the accumulation of ink received on the waste liquid tray. With the goal.

  The present invention relates to a plurality of recording heads that discharge ink, a waste liquid tray that receives ink discharged from the plurality of recording heads, an ink discharge unit that discharges ink to the outside of the waste liquid tray, and the plurality of the plurality of recording heads A waste tray that is disposed below the recording head and that inclines so as to guide the received ink to the ink discharge portion, and the drying rate of the ink among the plurality of recording heads is A recording head that discharges ink having a high dry viscosity, which is the viscosity of the ink in the same case, relates to an ink jet recording apparatus that is disposed closer to the ink discharge portion than a recording head that discharges ink having a low dry viscosity.

  According to the present invention, there is provided an ink jet recording apparatus that includes a plurality of recording heads and a waste liquid tray that receives ink discharged from the plurality of recording heads, and can reduce accumulation of ink received on the waste liquid tray. can do.

1 is a longitudinal sectional view schematically showing an outline of an inkjet recording apparatus 1 according to a first embodiment of the present invention from the front side. FIG. 2 is a front view showing a peripheral portion of the recording unit 20 and the conveyance unit 30 in the inkjet recording apparatus 1 of the first embodiment. 2 is a plan view showing peripheral portions of a recording unit 20, a transport unit 30, and a cap unit 50 in the inkjet recording apparatus 1 of the first embodiment. FIG. It is a front view which shows the state which the cap 51 moved below the inkjet recording device 1 shown in FIG. 2 is a longitudinal sectional view schematically showing the entire structure of a cap unit 50. FIG. 2A and 2B are diagrams illustrating a waste ink tray 60 according to the first embodiment, in which FIG. 1A is a plan view, FIG. 1B is a cross-sectional view of a first valley inclined portion 65 as viewed from a paper conveyance direction P, and FIG. It is sectional drawing seen from. 6A and 6B are diagrams illustrating a waste ink tray 60A in an ink jet recording apparatus according to a second embodiment of the present invention, where FIG. 5A is a plan view, and FIG. C) is a cross-sectional view viewed from the paper width direction Y. FIG. 4A and 4B are views showing a waste ink tray 60B in an ink jet recording apparatus according to a third embodiment of the present invention, where FIG. 5A is a plan view, FIG. It is sectional drawing seen from. 6A and 6B are views showing a waste ink tray 60C in an ink jet recording apparatus according to a fourth embodiment of the present invention, where FIG. 5A is a plan view, FIG. 5B is a cross-sectional view viewed from a paper transport direction P, and FIG. It is sectional drawing seen from. FIG. 10 is a view showing a state where a waste ink tray 60D is provided in a wiping unit 70 in an ink jet recording apparatus according to a fifth embodiment of the present invention, and is a longitudinal sectional view schematically showing the entire structure of the wiping unit 70. It is a top view which shows the peripheral part of the recording part 20, the conveyance unit 30, and the wiping unit 70A about the inkjet recording device 1 of 6th Embodiment of this invention. It is a figure which shows the state by which the waste ink tray 60E in the inkjet recording device of 6th Embodiment of this invention is provided in the wiping unit 70A, and is a longitudinal cross-sectional view which shows typically the whole structure of the wiping unit 70A. FIG. 6 is a diagram illustrating a configuration of Experiment 1 of the present invention, and is a diagram illustrating a configuration when a first ink discharge hole 64 is at one end of a waste ink tray 60. FIG. 6 is a diagram illustrating a configuration of Experiment 2 of the present invention, and is a diagram illustrating a configuration when a first ink discharge hole 64 is on the center side of a waste ink tray 60.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
The outline of the overall structure of the inkjet recording apparatus 1 according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view schematically showing the outline of the ink jet recording apparatus 1 according to the first embodiment of the present invention from the front side. FIG. 2 is a front view illustrating the peripheral portion of the recording unit 20 and the transport unit 30 in the inkjet recording apparatus 1 of the first embodiment. FIG. 3 is a plan view showing peripheral portions of the recording unit 20, the transport unit 30, and the cap unit 50 in the inkjet recording apparatus 1 of the first embodiment. FIG. 4 is a front view showing a state where the cap 51 is moved below the ink jet recording apparatus 1 shown in FIG.

As shown in FIGS. 1 to 4, the inkjet recording apparatus 1 according to the first embodiment includes a recording unit 20, a transport unit 30, an elevating device 40 for the transport unit 30, a cap unit 50, and a main body 2. And a wiping unit 70.
The ink jet recording apparatus 1 of the first embodiment further includes a paper feed cassette 3, a paper feed roller 4, a paper transport path 5, a registration roller pair 6, a drying device 7, a paper discharge roller pair 8, and a discharge roller. A paper slot 9 and a paper discharge tray 10 are provided.

  As shown in FIGS. 1 to 4, the transport unit 30 includes a drive roller 32, a driven roller 33, a transport belt 31 that is stretched over the drive roller 32 and the driven roller 33, and a tension that adjusts the tension of the transport belt 31. A roller 34 and an air suction unit 36 are provided. A large number of suction through holes (not shown) are provided on the upper surfaces of the transport belt 31 and the air suction unit 36, respectively.

When the driving roller 32 and the driven roller 33 rotate counterclockwise when viewed from the front, the transport surface 31A formed by the upper surface portion of the transport belt 31 is one of the paper transport directions P in the horizontal plane (XY plane). To the other side in the horizontal direction. That is, on the conveyance surface 31 </ b> A of the conveyance belt 31, the sheet conveyance direction P substantially coincides with the horizontal direction X. The air suction unit 36 is disposed on the lower side (opposite side) of the conveyance surface 31 </ b> A of the conveyance belt 31.
As the conveyor belt 31, a belt in which both ends are overlapped and joined to form an endless shape, a seamless belt (seamless), or the like can be used.

  As shown in FIGS. 2 and 3, during a predetermined recording, the paper T as a recording medium is introduced onto the transport surface 31 </ b> A of the transport belt 31 from one side in the paper transport direction P. With the operation of the air suction unit 36, a suction force acting on the transport belt 31 is generated on the transport surface 31A through the suction through hole (not shown). The paper T introduced onto the transport surface 31A of the transport belt 31 is attracted to the transport surface 31A by the suction force and transported toward the other side in the paper transport direction P. Thus, an image or the like is recorded on the paper T by ejecting ink from the recording head 22 of the recording unit 20 to be described later toward the paper T being transported while being attracted to the transport surface 31A of the transport belt 31. (Printed).

  As shown in FIG. 1, the paper feed cassette 3 accommodates the paper T in a stacked state, and is disposed on the upstream side of the paper transport direction P of the transport unit 30 below the inside of the main body 2. The paper feed roller 4 is disposed above the paper feed cassette 3. The paper feed roller 4 feeds the paper T toward the upper right of the paper feed cassette 3 in FIG.

  The sheet conveyance path 5, the registration roller pair 6, the recording unit 20, and the conveyance unit 30 are disposed on the downstream side in the sheet conveyance direction P of the sheet feeding cassette 3. The paper T sent out from the paper feed cassette 3 reaches the registration roller pair 6 through the paper transport path 5. The registration roller pair 6 corrects the oblique feeding of the paper T and feeds the paper T again. A paper leading edge detection sensor (not shown) is provided in the paper conveyance path 5 between the recording unit 20 and the registration roller pair 6. The front end portion of the paper T is detected by the paper front end detection sensor, and based on the detected timing, the recording unit 20 performs an ink ejection operation as described later.

  As shown in FIG. 1, the drying device 7 is arranged on the downstream side in the paper transport direction P of the transport unit 30 above the inside of the main body 2. The drying device 7 dries the ink on the paper T after being recorded by the ink ejected by the recording unit 20.

  The paper discharge roller pair 8, the paper discharge port 9, and the paper discharge tray 10 are arranged in this order on the downstream side in the paper transport direction P of the drying device 7. The paper T, which has been dried by the drying device 7, is sent to the downstream side in the paper transport direction P by the paper discharge roller pair 8, and passes through the paper discharge port 9 to a paper discharge tray 10 provided outside the main body 2. Sent to the outside of the main body 2.

  As shown in FIGS. 1 to 3, the recording unit 20 includes recording heads 22 corresponding to four colors. The recording heads 22 corresponding to the four colors are a recording head 22Y for yellow, a recording head 22K for black, a recording head 22C for cyan, and a recording head 22M for magenta. These four color recording heads 22Y, 22K, 22C and 22M extend long along the paper width direction Y perpendicular to the paper transport direction P (horizontal direction X). The recording heads 22 </ b> Y, 22 </ b> K, 22 </ b> C, and 22 </ b> M are arranged in order from the upstream side to the downstream side in the paper transport direction P along the paper transport direction P of the transport belt 31. In the first embodiment, in each of the four color recording heads 22Y, 22K, 22C, and 22M, one recording head per one color recording head is linearly arranged along the paper width direction Y.

  As shown in FIG. 1, below the transport unit 30, four ink tanks 23Y, 23K, 23C, and 23M are arranged corresponding to the four color recording heads 22Y, 22K, 22C, and 22M, respectively. . The four color inks are supplied from the four ink tanks 23Y, 23K, 23C, and 23M to the corresponding recording heads 22Y, 22K, 22C, and 22M through supply tubes (not shown). .

  In the following description, unless otherwise specified, “Y” is an identification symbol of the four color recording heads 22Y, 22K, 22C and 22M and the four ink tanks 23Y, 23K, 23C and 23M. ”,“ K ”,“ C ”, and“ M ”are omitted, and are simply referred to as“ recording head 22 ”and“ ink tank 23 ”. The same applies to “cap 51”, “wiper member 72”, “wiper case 73” and the like, which will be described later.

  Each recording head 22 of the recording unit 20 is a sheet placed on the conveying surface 31A of the conveying belt 31 based on image data information (for example, characters, figures, patterns) received from an external computer (not shown). Four colors of ink are ejected toward T. As shown in FIGS. 2 and 3, each recording head 22 is supported by a recording head support member 21, and is fixed to the main body 2 together with the recording head support member 21. Then, along with the rotational movement of the conveyor belt 31, four color inks are sequentially ejected from each recording head 22 at a predetermined timing. As a result, the four color inks of yellow, black, cyan, and magenta are superimposed on the paper T, and a color ink image is printed.

  As an ink discharge method from the recording head 22, for example, a piezo method in which ink is pushed out using a piezo element (not shown), or bubbles are generated by a heating element (not shown), and ink is discharged by applying pressure. Various discharge methods such as a thermal ink jet method can be employed.

  As shown in FIG. 1, the lifting device 40 of the transport unit 30 is disposed below the transport unit 30. The lifting device 40 moves the transport unit 30 up and down (moves) with respect to the recording head 22 in a direction Z (hereinafter also referred to as “vertical direction Z”) perpendicular to the horizontal plane (XY plane). By the movement of the transport unit 30 in the vertical direction Z by the lifting device 40, the transport surface 31 </ b> A of the transport belt 31 is configured to be relatively close to or away from the nozzle surface 221 (see FIG. 5) of the recording head 22. ing.

  As shown in FIG. 1, the lifting device 40 includes two eccentric cams 41 disposed on the upstream side and the downstream side in the paper transport direction P below the transport belt 31. A total of four eccentric cams 41 are provided, two on each of the front side and the back side of the transport unit 30. The eccentric circumferential surface of the eccentric cam 41 approaches the outer bottom surface of the transport unit 30 from below. As shown in FIG. 1, each eccentric cam 41 includes a shaft portion 42 that extends in the paper width direction Y, and is configured by a cam having a rotational axis that is unevenly distributed. The eccentric cam 41 is rotated around the shaft portion 42 via a motor (not shown). The eccentric cam 41 includes a plurality of bearings 43 at the peripheral edge thereof. A part of the peripheral surface of the bearing 43 protrudes outward from the peripheral surface of the eccentric cam 41.

  The bearing 43 is rotatable about an axis parallel to the rotation axis of the eccentric cam 41. The bearings 43 are sequentially arranged from the distal end side of the eccentric cam 41 toward the rotation axis side. In a normal printing state, as shown in FIG. 1, the bearing 43 farthest from the shaft portion 42 contacts the outer bottom surface of the transport unit 30 from below. Thereby, the conveyance unit 30 is moved upward to the highest position shown in FIG.

From this state, the eccentric cam 41 on the upstream side in the paper transport direction P is rotated counterclockwise in front view, and the eccentric cam 41 on the downstream side in the paper transport direction P is rotated clockwise in front view. Accordingly, the plurality of bearings 43 sequentially contact the outer bottom surface of the transport unit 30 in order of the bearing 43 farthest from the shaft portion 42 to the bearing 43 closest to the shaft portion 42. Therefore, the transport unit 30 can be lowered.
The plurality of bearings 43 are arranged at intervals such that when the eccentric cam 41 rotates, the two bearings 43 adjacent in the peripheral direction simultaneously have a period of contact with the outer bottom surface of the transport unit 30.

  By rotating the eccentric cam 41 of the elevating device 40 and lowering the conveyance unit 30, the conveyance surface 31 </ b> A of the conveyance belt 31 in the conveyance unit 30 is separated downward with respect to the recording head 22 as shown in FIG. 4. The As a result, the cap unit 50 is detached from the recording head 22. In the state where the cap unit 50 is detached from the recording head 22, ink is discharged from an ink discharge nozzle (not shown) of the recording head 22, thereby discharging high viscosity ink remaining in the nozzle. It is possible to execute discharge recovery processing for eliminating ink clogging, that is, purge.

  On the other hand, as shown in FIG. 2, the conveyance unit 30 is returned to the normal recording position (printing position) by rotating the eccentric cam 41 of the elevating device 40 in the direction opposite to the above to raise the conveyance unit 30. . As a result, the cap unit 50 can be attached to the nozzle surface 221 of the recording head 22.

As shown in FIGS. 2 to 4, the cap unit 50 is disposed at a position on the side of the recording unit 20 (outside the sheet conveyance area) and at a lower position during image formation. Further, the cap unit 50 moves below the recording unit 20 as necessary. The cap unit 50 includes a cap 51, a waste ink tray 60 as a waste liquid tray, a cap base member 52, a slide mechanism 53, and a vertical drive mechanism (not shown). The cap unit 50 is configured to be horizontally movable in the paper transport direction P by a slide mechanism 53 (see FIG. 3). 2 and 4, the drawing of the slide mechanism 53 of the cap unit 50 is omitted.
The cap unit 50 is disposed above the transport unit 30 and is configured to be lifted and lowered together with the transport unit 30 by the lifting device 40. Therefore, the cap unit 50 can detach the cap 51 from the recording head 22.

  As shown in FIG. 3, the cap 51 is arranged for each color (four colors) along the paper conveyance direction P (X), and further, one recording head 22 formed linearly in the paper width direction Y. In total, four are provided, one for each color.

The waste ink tray 60 is formed in a rectangular shape including all of the four recording heads 22 corresponding to the four colors in plan view.
The cap base member 52 holds the cap 51 and the waste ink tray 60.

  As shown in FIG. 3, the slide mechanism 53 extends in the paper width direction Y perpendicular to the paper transport direction P from the position where the recording unit 20 and the transport unit 30 are arranged toward the back side. The slide mechanism 53 is provided with two endless transfer belts 54 arranged at intervals in the paper transport direction P.

  The transfer belt 54 supports the cap base member 52 so as to straddle between the two transfer belts 54. Accordingly, as shown in FIG. 3, the slide mechanism 53 positions the cap base member 52 on the mounting position (indicated by a two-dot chain line) immediately below the recording unit 20 and on the back side of the arrangement location of the recording unit 20. It can be slid between the retracted position. That is, with the slide mechanism 53, the cap 51 can take two positions with respect to the recording head 22, that is, a mounting position below the recording head 22 and a retracted position located on the back side of the recording unit 20.

The cap 51 is attached to the recording head 22 by the cap unit 50. The operation will be described below.
When the cap 1 is attached to each recording head 22, the printer 1 uses the lifting device 40 (see FIG. 1) to lower the transport unit 30 from the position during normal printing, as shown in FIG. Thereby, a gap is formed between the recording unit 20 including the recording head 22 and the transport unit 30.

  Thereafter, the cap base member 52 is inserted into a gap formed between the recording head 22 of the recording unit 20 and the transport unit 30 using the slide mechanism 53. Then, the cap base member 52 is disposed below the recording head 22 and raised by a vertical drive mechanism (not shown). As a result, the cap 51 is mounted in contact with the nozzle surface 221 (see FIG. 5) on the bottom surface of the recording head 22. As the vertical drive mechanism, for example, a mechanism that synchronously drives cams and the like disposed at the four corners of the cap base member 52 is used.

The wiping unit 70 is configured to be disposed below the cap unit 50 and above the transport unit 30 (between the cap unit 50 and the transport unit 30).
As shown in FIG. 3, the wiping unit 70 includes a wiper support plate 71, a wiper member 72, and a wiper case 73.

The wiper member 72 cleans the nozzle surface 221 of the recording head 22. The wiper member 72 is disposed corresponding to the recording head 22.
Each wiper member 72 is formed in a plate shape by an elastic body. Two wiper members 72 are erected on the bottom of the wiper case 73 on the inner side of the wiper case 73 so as to be perpendicular to the paper width direction Y, two for each color, so as to extend vertically (extend in the vertical direction Z). Yes.

The wiper support plate 71 extends along the paper transport direction P, and is formed in a rectangular shape that is long in the paper transport direction P in plan view.
The wiper case 73 is formed in a square tube shape with a bottom that opens upward in the vertical direction Z. The wiper case 73 is fixed to the wiper support plate 71.

  The wiper support plate 71 is connected to a wiper moving unit (not shown). The wiper moving unit moves the wiper member 72 along the paper width direction Y by moving the wiper support plate 71 along the paper width direction Y. Thus, the wiper member 72 moves along the paper width direction Y after the tip abuts against the corresponding recording head 22 to clean the nozzle surface 221 of the recording head 22.

  The wiping unit 70 is configured to be horizontally movable in the paper width direction Y (see FIG. 1) by a horizontal movement mechanism (not shown). The wiping unit 70 is switched to a wiping position where the wiping unit 70 is disposed below the recording head 22 and can clean the recording head 22 or moved away from the wiping position in the horizontal direction by a moving operation by a horizontal movement mechanism. During a recording operation in the recording unit 20 or when the cap unit 50 is mounted on the nozzle surface 221 of the recording head 22, the wiping unit 70 is disposed at the retracted position.

  The wiping unit 70 can be moved up and down by a vertical drive mechanism (not shown) in a state where the wiping unit 70 is disposed below the recording head 22 by a horizontal movement mechanism and is disposed at a wiping position where the recording head 22 can be cleaned. Configured.

Next, with reference to FIGS. 3, 5, and 6, the configuration related to the characteristic part in the inkjet recording apparatus 1 of the first embodiment will be described in detail.
FIG. 5 is a longitudinal sectional view schematically showing the entire structure of the cap unit 50. 6A and 6B are views showing the waste ink tray 60 in the first embodiment, in which FIG. 6A is a plan view, FIG. 6B is a cross-sectional view of the first valley inclined portion 65 viewed from the paper transport direction P, and FIG. FIG. 6 is a cross-sectional view viewed from the paper width direction Y.

  As shown in FIG. 5, the cap unit 50 includes a cap 51 (51Y, 51K, 51C, 51M), a waste ink tray 60, a waste ink container 561, tubes 562, 563, and an ink collection pump 564. .

  As shown in FIG. 3, four caps 51 (51 Y, 51 K, 51 C, 51 M) are provided, one for each of the four recording heads 22, and can be arranged below each recording head 22. Composed. The waste ink tray 60 has a size including all of the four recording heads 22 in a plan view, and is disposed below the four caps 51. The waste ink container 561 is disposed at a position where it does not interfere with the transport unit 30. The tube 562 communicates a first ink discharge hole 64 (ink discharge portion) of the waste ink tray 60 described later with a waste ink container 561. The pump 564 communicates with the waste ink container 561 through the tube 563.

  As shown in FIG. 5, the cap 51 receives ink ejected (discharged) from an ink ejection nozzle (not shown) of the recording head 22. Each cap 51 has a bottom wall portion 512 formed with a bottom surface 511, a peripheral wall portion 513, and a second ink discharge hole 514.

As shown in FIG. 5, the bottom surface 511 of each cap 51 faces the nozzle surface 221 of the recording head 22 in a state where the caps 51 (51 </ b> Y, 51 </ b> K, 51 </ b> C, 51 </ b> M) are disposed below each recording head 22. And is inclined so as to descend from the peripheral wall portion 513 toward the second ink discharge hole 514.
The peripheral wall portion 513 rises upward from the peripheral edge portion of the bottom wall portion 512. The second ink discharge hole 514 is formed at the center of the bottom surface 511 and is a hole for discharging the ink received by the bottom surface 511 to the waste ink tray 60 positioned below.

  In other words, the cap 51 can be disposed between the recording head 22 and the waste ink tray 60 in the vertical direction Z corresponding to each of the plurality of recording heads 22. The cap 51 directly receives the ink discharged from the ink discharge nozzles and discharges the received ink from the second ink discharge hole 514 to the waste ink tray 60. The four caps 51 are integrated by connecting the outer surfaces of the peripheral wall portions 513 via a connecting plate 515 to form a second cap unit 516.

  Further, as shown in FIG. 5, a seal material 57 is interposed between the outer peripheral edge portion of the connecting plate 515 of the second cap unit 516 and the inner surface of the side wall portion 66 of the waste ink tray 60. Thereby, the seal part is formed. By interposing the sealing material 57, the outer peripheral edge portion of the second cap unit 516 is brought into close contact with the inner surface of the side wall portion 66 of the waste ink tray 60. As a result, the ventilation between the second cap unit 516 and the waste ink tray 60 is inhibited, and the ink is smoothly discharged.

Next, the waste ink tray 60 will be described in detail.
The waste ink tray 60 receives ink ejected from the four recording heads 22. As shown in FIG. 6, the waste ink tray 60 is formed in a size including all of the recording heads 22 (four colors) in a plan view, and can be arranged below the recording heads 22Y, 22K, 22C, and 22M. Has been.
The waste ink tray 60 includes a first ink guide inclined portion 62, a first valley inclined portion 65, a first ink discharge hole 64 as an ink discharge portion, and a side wall portion 66.

  The first ink guiding inclined portion 62 is disposed below the four recording heads 22. The first ink guiding inclined portion 62 is a portion inclined so as to guide the ink ejected from the four recording heads 22 received in the waste ink tray 60 to the first ink discharge hole 64 in the paper transport direction P. is there. The first ink guiding inclined portion 62 is inclined so as to be lowered toward the one end portion on the downstream side in the paper transport direction P. In other words, the first ink guiding inclined portion 62 is inclined downward toward the first ink discharge hole 64 described later in the direction in which the four recording heads 22 are arranged (paper conveyance direction P).

The ink received by the first ink guiding inclined portion 62 flows along an inclination direction (ink flowing direction) Q1 that is a direction in which the first ink guiding inclined portion 62 is inclined.
The inclination angle α1 of the first ink guiding inclined portion 62 with respect to the horizontal direction is, for example, in the range of not less than 2.5 degrees and not more than 15.0 degrees.

  As shown in FIG. 6, a plurality of grooves 623 extending along the direction in which the four recording heads 22 are arranged (paper conveyance direction P) are formed in the first ink guiding inclined portion 62. In the present embodiment, the first ink guiding inclined portion 62 is formed in a shape in which a plurality of V-shaped grooves 623 are continuous in the paper width direction Y when viewed from the paper transport direction P (X). The plurality of V-shaped grooves 623 extend along the ink flow direction Q1.

  The first valley inclined portion 65 is disposed adjacent to the lower end portion of the first ink guide inclined portion 62 in the inclination direction Q1. The first valley inclined portion 65 has a predetermined width and extends linearly over the entire area of the waste ink tray 60 in the paper width direction Y. The first valley inclined portion 65 is inclined so as to be lowered toward the first ink discharge hole 64. In other words, the first valley inclined portion 65 is inclined toward one end portion side in the paper width direction Y in the waste ink tray 60.

Ink that has flowed through the first ink guide inclined portion 62 is introduced into the first valley inclined portion 65. The ink introduced into the first valley inclined portion 65 flows along the flow direction R <b> 1 that is the direction in which the first valley inclined portion 65 is inclined, and is guided toward the first ink discharge hole 64.
The inclination angle β1 of the first valley inclined portion 65 with respect to the horizontal direction is, for example, in the range of not less than 2.5 degrees and not more than 15.0 degrees.

  The first ink discharge hole 64 discharges ink to the outside of the waste ink tray 60. The first ink discharge hole 64 is provided at a position on one end side of the first valley inclined portion 65 on the downstream side in the paper transport direction P (X) and on one end side in the paper width direction Y. In other words, the first ink discharge hole 64 is arranged on one end side in the direction (sheet width direction Y) in which the four recording heads 22 are arranged in the waste ink tray 60. The first ink discharge hole 64 discharges the four types of ink received by the waste ink tray 60 together.

  The side wall portion 66 stands upward from the upper end portion in the tilt direction of the first ink guide tilt portion 62. The side wall portion 66 is formed so as to surround the waste ink tray 60 and the first valley inclined portion 65 along the outer peripheral edges of the waste ink tray 60 and the first valley inclined portion 65.

  As shown in FIG. 5, the tube 562 is connected to the first ink discharge hole 64 of the waste ink tray 60 at one end (upper end). Further, the tube 562 is connected to the waste ink container 561 at the other end (lower end), and is opened inside the waste ink container 561. As a result, the ink received in the waste ink tray 60 and discharged from the first ink discharge hole 64 can be circulated and stored in the waste ink container 561 via the tube 562.

  Further, as shown in FIG. 5, the compression spring 58 is arranged between each cap 51 and the waste ink tray 60 in the vertical direction Z. The compression spring 58 moves the cap 51 in the state where the cap unit 50 is lifted to the recording head 22 side together with the transport unit 30 by the lifting device 40 and the cap 51 covers the nozzle surface 221 of the corresponding recording head 22. It is biased to move elastically toward the nozzle surface 221.

Next, the dry viscosity of the ink ejected from the four recording heads 22 in this embodiment will be described.
The ink drying viscosity is the viscosity of the ink when the ink drying rate of the inks ejected from the four recording heads 22 is the same.
The method for measuring the ink drying rate is as follows. First, ink is put into a container having a volume of 50 ml, and the initial ink weight is measured. Then, it puts in a 60 degreeC thermostat, measures an ink weight for every predetermined time, and measures a dry weight. The ink drying rate is obtained by the following equation.
Ink drying rate [%] = ((initial ink weight−ink weight after drying) / initial ink weight) × 100

In general, when the drying rate of the ink is the same, the ink is more solidified when the viscosity of the ink is high than when the viscosity is low, and the ink is harder to solidify when the viscosity of the ink is low than when the viscosity is high. .
In the present invention, the ink drying viscosity when the ink drying rate is 45% is preferably 60 mPa · s or more and less than 250 mPa · s.
The reason why the ink dry viscosity when the ink dry rate is 45% is preferably 60 mPa · s or more is that, in order to perform printing at a high density, the solid component pigment and resin contributing to the dry viscosity This is because a certain amount is necessary.
The reason why the ink dry viscosity when the ink dry rate is 45% is preferably less than 250 mPa · s is that when the ink dry rate is 45%, the ink dry viscosity becomes 250 mPa · s or more. This is because the fluidity of the ink deteriorates.

  In the present embodiment, the drying viscosity of the ink when the drying rate of the magenta ink ejected by the recording head 22M is 45% is, for example, 219 mPa · s. The drying viscosity of the ink when the drying rate of the cyan ink ejected by the recording head 22C is 45% is, for example, 189 mPa · s. The drying viscosity of the ink when the drying rate of the black ink ejected by the recording head 22K is 45% is, for example, 144 mPa · s. The drying viscosity of the ink when the drying rate of the yellow ink ejected by the recording head 22Y is 45% is, for example, 108 mPa · s.

  The four recording heads 22 move away from the recording head 22 that ejects ink having a high dry viscosity when the drying rate of the ejected ink is 45% as it goes away from the side closer to the first ink discharge hole 64. The recording heads 22 are arranged so as to be arranged in the order of ejecting ink having a low dry viscosity. Of the four recording heads 22, the recording head 22 that discharges ink having a high dry viscosity is disposed closer to the first ink discharge hole 64 than the recording head 22 that discharges ink having a low dry viscosity.

  In the present embodiment, the four recording heads 22 are sequentially arranged from the side closer to the first ink discharge hole 64 toward the side away from the upstream side in the paper transport direction P from the higher ink dry viscosity side to the lower side. Magenta recording head 22M (dry viscosity of ink when the drying rate is 45%: 219 mPa · s), cyan recording head 22C (dry viscosity of ink when the drying rate is 45%: 189 mPa · s), black Recording head 22K (dry viscosity of ink when the drying rate is 45%: 144 mPa · s) and yellow recording head 22Y (dry viscosity of ink when the drying rate is 45%: 108 mPa · s) are arranged in this order. The

The distance from the first ink discharge hole 64 to each recording head 22 in the present embodiment is, for example, as follows.
The distance L1 in the paper transport direction X from the first ink discharge hole 64 to the magenta recording head 22M is, for example, 0 mm or more and 20 mm or less as shown in FIG. The distance L2 in the paper transport direction X from the first ink discharge hole 64 to the cyan recording head 22C is, for example, 30 mm or more and 65 mm or less. The distance L3 in the paper transport direction X from the first ink discharge hole 64 to the black recording head 22K is, for example, 60 mm or more and 110 mm or less. The distance L4 in the paper transport direction X from the first ink discharge hole 64 to the yellow recording head 22Y is, for example, 90 mm or more and 155 mm or less.

Next, the ejection recovery process (purge) and the ink flow at that time will be described.
When the cap unit 50 is attached to the recording head 22, each cap 51 of the cap unit 50 covers the nozzle surface 221 of the recording head 22. Accordingly, when the recording head 22 is not used, it is possible to prevent the residual ink from drying and clogging of the nozzles, and foreign matters from entering the recording head 22 through the nozzles.

  Then, before starting the recording by the recording head 22 next, the cap unit 50 is lowered together with the transport unit 30 by the lifting device 40 so that the cap 51 is separated from the nozzle surface 221 of the recording head 22. Moved downwards.

  When the cap unit 50 is lowered below the recording head 22 in this way, each cap 51 in the cap unit 50 is disposed corresponding to a position immediately below the nozzle surface 221 of the recording head 22. In this state, the ejection recovery process is executed by ejecting ink from an ink ejection nozzle (not shown) of each recording head 22. The ejection recovery process is a process for preventing the occurrence of defective ink ejection by ejecting high-viscosity ink remaining in the nozzles when the recording unit 20 is stopped for a long time (not using the recording head 22). is there.

  The ink ejected (discharged) from the ink ejection nozzles of each recording head 22 as the ejection recovery process is executed is received by the bottom surface 511 of each cap 51 and then the second ink along the inclination of the bottom surface 511. It flows toward the discharge hole 514 side. Thereafter, the ink is discharged from the second ink discharge hole 514 of each cap 51 to the waste ink tray 60 positioned below.

  The ink discharged downward from each of the second ink discharge holes 514 of each cap 51 is received by the waste ink tray 60 and then flows along the inclination of the first ink guiding inclined portion 62 to be inclined to the first valley. Head to part 65. Then, the ink that has flowed along the inclination of the first ink guiding inclined portion 62 reaches the first valley inclined portion 65.

  Here, the dry viscosity of the ink used for the recording head 22 on the first ink discharge hole 64 side is high. Therefore, in the first ink guiding inclined portion 62, the ink having a high dry viscosity is pushed away toward the first ink discharge hole 64 by the ink having a low dry viscosity that is subsequently introduced. Therefore, ink having a high dry viscosity is washed away by ink having a low dry viscosity. Thereby, it is possible to reduce the accumulation of the ink ejected from the plurality of recording heads 22 on the waste ink tray 60.

In the first valley inclined portion 65, the four colors of ink that have flowed in from the first ink guiding inclined portion 62 merge. The ink merged in the first valley inclined portion 65 is guided toward the first ink discharge hole 64 by flowing along the first valley inclined portion 65, and is discharged together from the first ink discharge hole 64. The The ink discharged from the first ink discharge hole 64 is stored (stored) in the waste ink container 561 through the tube 562.
The ink stored in the waste ink container 561 is collected at a predetermined location (not shown) through the tube 563 in accordance with the operation of the pump 564.

According to the ink jet recording apparatus 1 of the first embodiment, for example, the following effects are exhibited.
In the inkjet recording apparatus 1 according to the first embodiment, a plurality of recording heads 22 that eject ink and a waste ink tray 60 that receives ink ejected from the plurality of recording heads 22, A first ink discharge hole 64 for discharging the ink to the first ink discharge hole 64 and a first ink guide inclined portion 62 which is disposed below the plurality of recording heads 22 and is inclined so as to guide the received ink to the first ink discharge hole 64. A recording head 22 that discharges ink having a high drying viscosity, which is the viscosity of the ink when the ink drying rate is the same, among the plurality of recording heads 22. It is arranged closer to the first ink discharge hole 64 than the recording head 22 to be ejected.

  Therefore, the recording head 22 that uses ink having a high dry viscosity is disposed near the first ink discharge hole 64, so that even if the ink having a high dry viscosity stays near the first ink discharge hole 64, the recording head 22 is dried. The low viscosity ink can push the high dry viscosity ink toward the first ink discharge hole 64 side. Thereby, the accumulation of the ink received by the waste ink tray 60 on the waste ink tray 60 can be reduced.

  Further, in the present embodiment, the plurality of recording heads 22 receives ink having a low drying viscosity from the recording head 22 that discharges ink having a high drying viscosity as it moves away from the side closer to the first ink discharge hole 64. The recording heads 22 to be ejected are arranged in order. Therefore, since the ink having a high dry viscosity is sequentially washed away toward the first ink discharge hole 64 by the ink having the low dry viscosity, a plurality of types of ink having different dry viscosities can be efficiently discharged from the first ink discharge hole 64. it can. Thereby, the accumulation of the ink received by the waste ink tray 60 on the waste ink tray 60 can be further reduced.

  The first ink discharge hole 64 is disposed on one end side in the direction in which the plurality of recording heads 22 are arranged in the waste ink tray 60 (paper transport direction P (X)), and the first ink guide inclined portion 62 is In the direction in which the plurality of recording heads 22 are arranged, the recording heads 22 are inclined downward toward the first ink discharge holes 64. Therefore, the ink ejected from the plurality of recording heads 22 can be smoothly moved to the first ink discharge hole 64 side along the inclination of the first ink guiding inclined portion 62 in the paper transport direction P. This further reduces the accumulation of ink ejected from the plurality of recording heads 22 on the waste ink tray 60.

  In the present embodiment, the first ink guide inclined portion 62 is formed with a plurality of grooves 623 extending along the direction in which the plurality of recording heads 22 are arranged (paper transport direction P (X)). Therefore, the ink ejected from the plurality of recording heads 22 can be smoothly moved to the first ink discharge hole 64 side along the plurality of grooves 623 extending along the paper transport direction P.

  In this embodiment, the ink drying viscosity when the ink drying rate is 45% is less than 250 mPa · s. Therefore, since the fluidity of the ink can be ensured, the ink received by the first ink guiding inclined portion 62 can be smoothly moved toward the first ink discharge hole 64.

  Next, another embodiment of the present invention will be described. The other embodiments will be described mainly with respect to differences from the first embodiment, the same reference numerals are given to the same configurations as those of the first embodiment, and detailed descriptions thereof will be omitted. In other embodiments, the description of the first embodiment is appropriately applied to points that are not particularly described. Also in other embodiments, the same effects as in the first embodiment can be obtained.

Second Embodiment
The second embodiment will be described with reference to FIG. 7A and 7B are views showing a waste ink tray 60A in the ink jet recording apparatus according to the second embodiment of the present invention. FIG. 7A is a plan view, and FIG. 7B is a view of the first valley inclined portion 65 as viewed from the paper transport direction P. Sectional view, (C) is a sectional view viewed from the paper width direction Y. FIG.

  As shown in FIG. 7, the waste ink tray 60A of the second embodiment has a position in the paper transport direction P of the first valley inclined portion 65A and a paper transport direction of the first ink discharge hole 64A, as compared with the first embodiment. The position of P, the configuration of the first ink guiding inclined portion 62A, the order of the four recording heads 22 and the like are mainly different.

  The first ink guiding inclined portion 62A has two inclined portions 621 and 622 that are spaced apart in the paper transport direction P with the first valley inclined portion 65A disposed in the center of the paper transport direction P interposed therebetween. Inclined portions 621 and 622 of the first ink guiding inclined portion 62A are symmetrical in the paper transport direction P with the first valley inclined portion 65A interposed therebetween.

The inclined portions 621 and 622 of the first ink guiding inclined portion 62A are inclined upward toward the upstream side and the downstream side in the paper transport direction P as the distance from the first valley inclined portion 65A increases.
The inclination angle α2 of the inclined portions 621 and 622 of the first ink guiding inclined portion 62A with respect to the horizontal direction is, for example, not less than 1.5 degrees and not more than 15.0 degrees.

  A plurality of continuous V-shaped grooves 623 extending along the paper transport direction P are formed in the first ink guiding inclined portion 62A, as in the first embodiment.

The first valley inclined portion 65A of the second embodiment differs from the first valley inclined portion 65 of the first embodiment in the position in the paper transport direction P.
As shown in FIG. 7, the first valley inclined portion 65A has an inclination direction Q21, Q22 of each of the inclined portions 621, 622 of the first ink guiding inclined portion 62A at the center position in the paper transport direction P in the waste ink tray 60A. Arranged adjacent to the lower end.

The first valley inclined portion 65 has a predetermined width and extends linearly over the entire area in the paper width direction Y of the waste ink tray 60. The first valley inclined portion 65 </ b> A is inclined in the inclination direction R <b> 1 so as to be lowered toward the first ink discharge hole 64. Therefore, the ink introduced into the first valley inclined portion 65 </ b> A is guided toward the first ink discharge hole 64.
The inclination angle β1 of the first valley inclined portion 65A with respect to the horizontal direction is the same angle as the inclination angle β1 of the first valley inclined portion 65 of the first embodiment.

  The first ink discharge hole 64A is provided at a central position in the paper transport direction P (X) in the first valley inclined portion 65A and at a position on one end side in the paper width direction Y. The first ink discharge hole 64 </ b> A discharges four types of ink received by the waste ink tray 60 together with the first ink discharge hole 64 of the first embodiment.

  The four recording heads 22 are separated from the side closer to the first ink discharge hole 64A toward the upstream side and the downstream side in the paper transport direction P around the first valley inclined portion 65A in the paper transport direction P. The recording heads 22 are arranged in order from the recording head 22 that ejects ink having a high dry viscosity to the recording head 22 that ejects ink having a low dry viscosity.

  In the present embodiment, the four recording heads 22 are directed from the first valley inclined portion 65A side to the upstream side in the sheet conveying direction P on the upstream side in the paper conveying direction P with respect to the first valley inclined portion 65A. In this order, cyan recording head 22C (dry viscosity of ink when drying rate is 45%: 189 mPa · s), black recording head 22K (dry viscosity of ink when drying rate is 45%: 144 mPa · s) Is placed. The cyan recording head 22C (dry viscosity of ink when the drying rate is 45%: 189 mPa · s) is more than the black recording head 22K (dry viscosity of ink when the drying rate is 45%: 144 mPa · s). The first valley inclined portion 65A (the first ink discharge hole 64A) is disposed in the vicinity.

  Further, the four recording heads 22 are magenta in order from the first valley inclined portion 65A side to the downstream side in the sheet conveying direction P on the downstream side in the sheet conveying direction P with respect to the first valley inclined portion 65A. Recording head 22M (dry viscosity of ink when the drying rate is 45%: 219 mPa · s) and yellow recording head 22Y (dry viscosity of ink when the drying rate is 45%: 108 mPa · s) are arranged. . The magenta recording head 22M (dry viscosity of ink when the drying rate is 45%: 219 mPa · s) is more than the yellow recording head 22Y (dry viscosity of ink when the drying rate is 45%: 108 mPa · s). The first valley inclined portion 65A (the first ink discharge hole 64A) is disposed in the vicinity.

The distance from the first ink discharge hole 64A to each recording head 22 in the present embodiment is, for example, as follows.
As shown in FIG. 7, the distance L11 in the paper transport direction X from the first ink discharge hole 64A to the cyan recording head 22C and the paper transport direction X from the first ink discharge hole 64A to the magenta recording head 22M. The distance L12 is, for example, 0 mm or more and 20 mm or less. The distance L13 in the paper transport direction X from the first ink discharge hole 64A to the black recording head 22K and the distance L14 in the paper transport direction X from the first ink discharge hole 64A to the yellow recording head 22Y are, for example, 30 mm or more. 65 mm or less.

  As described above, in the second embodiment, the recording head 22 that ejects ink having a high dry viscosity is disposed on the first ink discharge hole 64A side. Therefore, according to the second embodiment, similarly to the first embodiment, it is possible to reduce the accumulation of the ink ejected from the plurality of recording heads 22 and received by the waste ink tray 60A on the waste ink tray 60A. .

<Third Embodiment>
A third embodiment will be described with reference to FIG. 8A and 8B are views showing a waste ink tray 60B in the ink jet recording apparatus according to the third embodiment of the present invention. FIG. 8A is a plan view, FIG. 8B is a cross-sectional view as viewed from the paper transport direction P, and FIG. FIG. 6 is a cross-sectional view viewed from the paper width direction Y.

  In the third embodiment, as shown in FIG. 8, the second valley inclined portion 68, the first ink discharge hole 64 </ b> B, and the second ink guide inclined portion 67 are configured as compared with the first embodiment and the second embodiment. Etc. are mainly different. Further, regarding the order of the four recording heads 22 of the third embodiment, the position of the first ink discharge hole 64B of the third embodiment in the paper transport direction P is the same as the first ink discharge hole 64A of the second embodiment. Since it is the central position in the paper transport direction P, the order is the same as in the second embodiment.

  In the third embodiment, the first ink guiding inclined portions 62 and 62A in the first and second embodiments are inclined so as to guide the ink to the first ink discharge holes 64 and 64A. The second valley inclined portion 68 as the inclined portion is different from the first and second embodiments in that the second valley inclined portion 68 is inclined so as to guide the ink to the first ink discharge hole 64B.

  The waste ink tray 60C of the third embodiment includes a second ink guide inclined portion 67, a second valley inclined portion 68 as an inclined portion, a first ink discharge hole 64B as an ink discharge portion, a side wall portion 66, Have

  The second ink guiding inclined portion 67 has two inclined portions 671 and 672 that are spaced apart in the paper width direction Y across the second valley inclined portion 68 disposed at the center in the paper width direction Y. The inclined portions 671 and 672 of the second ink guiding inclined portion 67 are symmetrical in the paper width direction Y with the second valley inclined portion 68 interposed therebetween.

The inclined portions 671 and 672 of the second ink guiding inclined portion 67 are inclined in the inclined direction R31 and the inclined direction R32 so as to go upward in the paper width direction Y as they are separated from the second valley inclined portion 68.
The inclination angle β3 of the inclined portions 671 and 672 of the second ink guiding inclined portion 67 with respect to the horizontal direction is, for example, not less than 1.5 degrees and not more than 15.0 degrees.

  A plurality of continuous V-shaped grooves 673 extending along the paper width direction Y are formed in the second ink guiding inclined portion 67.

  The second valley inclined portion 68 has a predetermined width and extends linearly over the entire area of the waste ink tray 60 in the paper transport direction P (X). The second valley inclined portion 68 has two inclined portions 681 and 682 that are separated from each other in the paper transport direction P (X) with the first ink discharge hole 64B interposed therebetween. The inclined portions 681 and 682 of the second valley inclined portion 68 have a symmetric shape with respect to the first ink discharge hole 64B in the paper transport direction P.

  The inclined portions 681 and 682 of the second valley inclined portion 68 are inclined in the inclined direction Q31 and the inclined direction Q32 so as to go upward as they move away from the first ink discharge hole 64B on the upstream side and the downstream side in the paper transport direction P. Inclined.

Ink that has flowed through the second ink guiding inclined portion 67 is introduced into the second valley inclined portion 68. The ink introduced into the second valley inclined portion 68A flows along the inclined directions Q31 and Q32 that are directions in which the second valley inclined portion 68 is inclined, and is guided toward the first ink discharge hole 64B.
The inclination angle α3 of the inclined portions 681 and 682 of the second valley inclined portion 68 with respect to the horizontal direction is, for example, not less than 1.5 degrees and not more than 15.0 degrees.

  The first ink discharge hole 64B is provided at the center position in the sheet transport direction P (X) in the second valley inclined portion 68 and at the center position in the sheet width direction Y. The first ink discharge hole 64B discharges four types of ink received by the waste ink tray 60 together with the first ink discharge hole 64 of the first embodiment.

  The four recording heads 22 are separated from the side closer to the first ink discharge hole 64B toward the upstream side and the downstream side in the paper transfer direction P around the first ink discharge hole 64B in the paper transfer direction P. The recording heads 22 are arranged in order from the recording head 22 that ejects ink having a high dry viscosity to the recording head 22 that ejects ink having a low dry viscosity.

In the present embodiment, the four recording heads 22 are directed from the first ink discharge hole 64B side to the upstream side in the paper transport direction P on the upstream side in the paper transport direction P with respect to the first ink discharge hole 64B. In this order, cyan recording head 22C (dry viscosity of ink when drying rate is 45%: 189 mPa · s), black recording head 22K (dry viscosity of ink when drying rate is 45%: 144 mPa · s) Is placed.
Further, the four recording heads 22 are magenta in order from the first ink discharge hole 64B toward the downstream side in the paper transport direction P on the downstream side in the paper transport direction P with respect to the first ink discharge hole 64B. Recording head 22M (dry viscosity of ink when the drying rate is 45%: 219 mPa · s) and yellow recording head 22Y (dry viscosity of ink when the drying rate is 45%: 108 mPa · s) are arranged. .

  As described above, in the third embodiment, the recording head 22 that ejects ink having a high dry viscosity is disposed on the first ink discharge hole 64B side. Therefore, according to the third embodiment, as in the first and second embodiments, the ink ejected from the plurality of recording heads 22 and received by the waste ink tray 60B is deposited on the waste ink tray 60B. Can be reduced.

<Fourth embodiment>
The fourth embodiment will be described with reference to FIG. 9A and 9B are views showing a waste ink tray 60C in the ink jet recording apparatus according to the fourth embodiment of the present invention. FIG. 9A is a plan view, FIG. 9B is a cross-sectional view as viewed from the paper transport direction P, and FIG. FIG. 6 is a cross-sectional view viewed from the paper width direction Y.

As shown in FIG. 9, the fourth embodiment is mainly different from the third embodiment in the position of the first ink discharge hole 64C in the paper transport direction P, the configuration of the second valley inclined portion 68A, and the like.
As for the order of the four recording heads 22 of the fourth embodiment, the position of the first ink discharge hole 64C of the fourth embodiment in the paper transport direction P is the same as that of the first ink discharge hole 64 of the first embodiment. Since this is the downstream end in the paper transport direction P, the order is the same as in the first embodiment.

  As shown in FIG. 9, the second valley inclined portion 68 </ b> B of the fourth embodiment has a predetermined width in the paper transport direction P (X) of the waste ink tray 60 at the center position in the paper width direction Y of the waste ink tray 60. It extends linearly over the entire area. The second valley inclined portion 68A is inclined in the inclination direction Q4 so as to be lowered toward the first ink discharge hole 64C disposed at the downstream end portion in the paper transport direction P (X).

The ink that has flowed through the second ink guiding inclined portion 67 is introduced into the second valley inclined portion 68A. The ink introduced into the second valley inclined portion 68A flows along the inclined direction Q4 that is the direction in which the second valley inclined portion 68A is inclined, and is guided toward the first ink discharge hole 64C.
The inclination angle α4 of the second valley inclined portion 68A with respect to the horizontal direction is, for example, in the range of not less than 2.5 degrees and not more than 15.0 degrees.

  The first ink discharge hole 64B is provided at the position of the downstream end of the second valley inclined portion 68 in the paper transport direction P (X) and at the center position in the paper width direction Y. Similarly to the first ink discharge hole 64 of the first embodiment, the first ink discharge hole 64C discharges four types of ink received by the waste ink tray 60 together.

The four recording heads 22 are arranged in the order of the recording head 22 that discharges ink having a low drying viscosity from the recording head 22 that discharges ink having a high drying viscosity toward the side away from the side near the first ink discharge hole 64C. Are arranged as follows.
In the present embodiment, the four recording heads 22 are, as in the first embodiment, the ink dry viscosity from the side closer to the first ink discharge hole 64C toward the upstream side in the paper transport direction P. The magenta recording head 22M (dry viscosity of ink when the drying rate is 45%: 219 mPa · s) and cyan recording head 22C (drying of ink when the drying rate is 45%) are sequentially from the higher side to the lower side. Viscosity: 189 mPa · s), black recording head 22K (dry viscosity of ink when the drying rate is 45%: 144 mPa · s), yellow recording head 22Y (dry viscosity of the ink when the drying rate is 45%: 108 mPa · s).

  As described above, in the fourth embodiment, the recording head 22 that ejects ink having a high dry viscosity is disposed on the first ink discharge hole 64C side. Therefore, according to the fourth embodiment, as in the first to third embodiments, the ink discharged from the plurality of recording heads 22 and received by the waste ink tray 60C is deposited on the waste ink tray 60C. Can be reduced.

<Fifth Embodiment>
The fifth embodiment will be described with reference to FIG. FIG. 10 is a view showing a state where the waste ink tray 60D is provided in the wiping unit 70 in the ink jet recording apparatus according to the fifth embodiment of the present invention, and is a longitudinal sectional view schematically showing the entire structure of the wiping unit 70.

In the fifth embodiment, as shown in FIG. 10, the waste ink tray 60D is provided in the wiping unit 70 in place of the configuration in which the waste ink tray 60 is provided in the cap unit 50 in the first embodiment. Different.
As shown in FIG. 10, the wiping unit 70 includes a wiper support plate 71, a wiper member 72 (72Y, 72K, 72C, 72M), a wiper case 73 (73Y, 73K, 73C, 73M), and a waste ink tray 60D. A waste ink container 561, tubes 562 and 563, and a pump 564 for collecting ink.

  As shown in FIGS. 3 and 10, a total of eight wiper members 72 (72Y, 72K, 72C, 72M) are provided corresponding to each of the four recording heads 22, and below each recording head 22. It can be arranged in The wiper member 72 (72Y, 72K, 72C, 72M) is erected on the bottom of the wiper case 73 (73Y, 73K, 73C, 73M) substantially vertically (so as to extend in the vertical direction Z) on the bottom. Yes.

  As shown in FIGS. 3 and 10, the bottom portion of the wiper case 73 is formed with a third ink discharge hole 731 that passes through the bottom portion of the wiper case 73 and opens downward in the vertical direction Z. The third ink discharge hole 731 discharges the ink cleaned from the nozzle surface 221 of the recording head 22 by the wiper member 72 to the waste ink tray 60D.

  The waste ink tray 60D receives the ink discharged from the third ink discharge hole 731 of the wiper case 73. The waste ink tray 60D is formed in a rectangular shape that is long in the paper transport direction P in plan view. The waste ink tray 60D is disposed below the four wiper cases 73 (73Y, 73K, 73C, 73M).

In the fifth embodiment, the configuration of the waste ink tray 60D is the same as that of the waste ink tray 60 of the first embodiment except that the length in the paper width direction Y is shorter than that of the waste ink tray 60 in the first embodiment. The configuration is the same. Therefore, the description of the waste ink tray 60 of the first embodiment is applied or used, and the description of the waste ink tray 60D of the fifth embodiment is omitted.
The configurations of the waste ink container 561, the tube 562, and the pump 564 are the same as those in the first embodiment, and thus the description thereof is omitted.

  In the wiping unit 70 configured as described above, the ink scraped off from the nozzle surface 221 of the recording head 22 by the wiper member 72 is temporarily stored in the wiper case 73 and discarded via the third ink discharge hole 731. The ink is discharged toward the ink tray 60D. The waste ink tray 60 </ b> D receives the ink discharged from the third ink discharge hole 731 of the wiper case 73.

  As described above, in the fifth embodiment, the waste ink tray 60D is provided in the wiping unit 70. According to the fifth embodiment, similarly to the first to fourth embodiments, accumulation of ink discharged from the plurality of recording heads 22 and received by the waste ink tray 60D on the waste ink tray 60D is reduced. be able to.

<Sixth Embodiment>
The sixth embodiment will be described with reference to FIGS. 11 and 12. FIG. 11 is a plan view showing the periphery of the recording unit 20, the transport unit 30, and the wiping unit 70A in the inkjet recording apparatus 1 according to the sixth embodiment of the present invention. FIG. 12 is a view showing a state in which the waste ink tray 60E is provided in the wiping unit 70A in the ink jet recording apparatus according to the sixth embodiment of the present invention, and is a longitudinal sectional view schematically showing the entire structure of the wiping unit 70A.

In the sixth embodiment, as shown in FIGS. 11 and 12, instead of the configuration in which the waste ink tray 60 is provided in the cap unit 50 in the first embodiment, the waste ink tray 60E is provided in the wiping unit 70A. Mainly different. Further, the sixth embodiment differs from the fifth embodiment in the configuration of the wiping unit 70A.
As shown in FIGS. 11 and 12, the wiping unit 70A includes a wiper stay 75, a wiper member 72 (72Y, 72K, 72C, 72M), a waste ink tray 60E, a waste ink container 561, and tubes 562 and 563. And a pump 564 for collecting the ink. The sixth embodiment also includes the cap unit 50 shown in FIG. 3 in the first embodiment, but the illustration of the cap unit 50 is omitted in FIG. 11.

  As shown in FIGS. 11 and 12, four wiper members 72 (72Y, 72K, 72C, 72M) are provided, one for each of the four recording heads 22, and below each recording head 22. It can be arranged in The wiper member 72 (72Y, 72K, 72C, 72M) is erected on the wiper stay 75 substantially vertically (so as to extend in the vertical direction Z).

  The wiper stay 75 extends along the paper transport direction P, and is formed in a straight line shape that is short in the paper width direction Y and long in the paper transport direction P in plan view.

  The wiper stay 75 is connected to a wiper moving unit (not shown). The wiper moving unit moves the wiper member 72 along the paper width direction Y by moving the wiper stay 75 along the paper width direction Y. Thus, the wiper member 72 moves along the paper width direction Y after the tip abuts against the corresponding recording head 22 to clean the nozzle surface 221 of the recording head 22.

  The waste ink tray 60E receives the ink scraped off from the nozzle surface 221 of the recording head 22 by the wiper member 72 (72Y, 72K, 72C, 72M). Similar to the waste ink tray 60 of the first embodiment, the waste ink tray 60E is formed in a rectangular shape including all of the four recording heads 22 corresponding to the four colors in plan view. The waste ink tray 60E is disposed below the area where the wiper stay 75 moves.

In the sixth embodiment, the configuration of the waste ink tray 60E is the same as the configuration of the waste ink tray 60 of the first embodiment. Therefore, description of the waste ink tray 60E of the sixth embodiment is omitted by applying or using the description of the waste ink tray 60 of the first embodiment.
The configurations of the waste ink container 561, the tube 562, and the pump 564 are the same as those in the first embodiment, and thus the description thereof is omitted.

  In the wiping unit 70A configured as described above, the ink scraped off from the nozzle surface 221 of the recording head 22 by the wiper member 72 is dropped toward the waste ink tray 60E. The waste ink tray 60E receives the ink scraped off from the nozzle surface 221 of the recording head 22 by the wiper member 72.

  As described above, in the sixth embodiment, the waste ink tray 60E is provided in the wiping unit 70A. According to the sixth embodiment, as in the first to fifth embodiments, accumulation of ink discharged from the plurality of recording heads 22 and received by the waste ink tray 60E on the waste ink tray 60E is reduced. be able to.

As mentioned above, although preferred embodiment of this invention was described, this invention can be implemented with a various form, without being limited to embodiment mentioned above.
For example, in the first embodiment and the second embodiment, a plurality of V-shaped grooves 623 are formed in the first ink guiding inclined portions 62 and 62A of the waste ink trays 60 and 60A. Is not limited to. For example, it may be formed in a planar shape that does not have a plurality of V-shaped grooves.

  In the above embodiment, the first ink discharge hole 64 is disposed at the end or the center of the waste ink tray 60 on the downstream side in the paper transport direction P. However, the present invention is not limited to this. For example, the first ink discharge hole 64 may be disposed, for example, at an upstream end of the waste ink tray 60 in the paper transport direction P.

  In the above-described embodiment, the four recording heads 22 are arranged so as to be arranged in descending order of the drying viscosity when the ink drying rate is 45%. However, the present invention is not limited to this. For example, the four recording heads 22 may be arranged in order of increasing drying viscosity when the ink drying rate is 50%.

  Further, in the embodiment, as the four recording heads 22 are moved away from the side closer to the first ink discharge hole 64, the ink having a lower drying viscosity is discharged from the recording head that discharges the ink having a higher drying viscosity. Although the recording heads are arranged in order of ejection, the present invention is not limited to this. Of the four recording heads 22, the recording head that discharges ink having a relatively high ink dry viscosity may be disposed in the vicinity of the first ink discharge hole 64.

  In the embodiment, the example in which one recording head is arranged in each of the four color recording heads 22Y, 22K, 22C, and 22M has been described. For example, in the four color recording heads 22Y, 22K, 22C, and 22M, three recording heads may be arranged in a zigzag pattern along the paper width direction Y, for example.

Next, examples and comparative examples of the present invention will be described. However, the present invention is not limited to the following examples.
The composition and preparation method of the ink used in this example, the evaluation methods of the examples and comparative examples, and the evaluation results of the examples and comparative examples are shown below.

<Ink composition>
(Contains pigment dispersion)
The pigment dispersion formulation of the ink is as shown in Table 1.

表１において、顔料に対する樹脂量の比率は任意に変化させることができる。
樹脂に関しては、水溶性（アルカリ可溶性樹脂）であり、ＫＯＨで等量中和している。

In Table 1, the ratio of the resin amount to the pigment can be arbitrarily changed.
As for the resin, it is water-soluble (alkali-soluble resin) and is neutralized with an equivalent amount of KOH.

(Synthesis of acrylic resin)
The used acrylic resin will be described.
As a synthesis method, a macromonomer synthesis method which is an easy and stable polymerization method was adopted.
An oligomer (Mn = 6000, trade name: AS-6, manufactured by Toa Gosei Co., Ltd.) with a (meth) acryloyl group bonded to one molecular end of polystyrene is used, and other monomers are added to match the resin ratio. did.
The monomer was polymerized in MEK with a known initiator such as 2,2′-azobisisobutyronitrile and azo compounds such as 2,2′-azobis (2,4-dimethylvaleronitrile). . After completion of the reaction, the solvent was distilled off under reduced pressure.
Moreover, the molecular weight of the obtained resin was confirmed by gel filtration chromatography, the weight average molecular weight was confirmed, and the acid value was also confirmed by titration.
The resin used has a molecular weight (weight average) of about 50,000 and an acid value of 150.

(Ink creation method)
The ink was prepared by adjusting the materials shown in Table 2.

※１：顔料％が４〜９％になるように調整した
※２：インクの粘度は、６ｍＰａ・ｓになるように、グリセリンとイオン交換水で調整した。

* 1: The pigment% was adjusted to 4 to 9%. * 2: The viscosity of the ink was adjusted with glycerin and ion-exchanged water so as to be 6 mPa · s.

(Dry viscosity of ink)
Regarding the dry viscosity of the ink, the viscosity was measured when the initial viscosity and the drying rate were 30%, 40%, 45%, and 50%. In the following, three types of ink were selected from the inks used this time (see Table 4), and Table 3 shows the viscosity values and the increasing tendency during drying.

(How to determine the ink drying rate)
The ink is put into a container having a volume of 50 ml, and the initial ink weight is measured. Then, it puts in a 60 degreeC thermostat, measures an ink weight for every predetermined time, and measures a dry weight. Then, the ink weight drying rate (drying rate) is obtained by the following equation.
Ink weight drying rate [%] = {(initial ink weight−ink weight after drying) / initial ink weight} × 100

  From Table 3, it can be seen that the viscosity tends to increase from the time when the drying rate is about 30%. However, when the drying rate is 30 to 40%, there is not much difference in the type of ink. On the other hand, when the drying rate is 45%, the tendency of the drying viscosity of each ink appears remarkably. Therefore, in order to grasp the difference in the characteristics of each ink, the drying viscosity when the drying rate is 45% is used as an index for the examination.

(Ink used and its dry viscosity)
Table 4 below shows the pigment concentration of the ink used and the drying viscosity when the drying rate is 45%. In Table 4, it was confirmed that there was a correlation between the total solid content (pigment + resin amount) of each ink used and the drying viscosity at a drying rate of 45%.

表４は、樹脂量・顔料比率が０．５５の場合である。

Table 4 shows the case where the resin amount / pigment ratio is 0.55.

  Here, the evaluation method and the contents of the experiment will be described with reference to FIGS. 13A and 13B. FIG. 13A is a diagram showing the configuration of Experiment 1 of the present invention, and is a diagram showing the configuration when the position of the first ink discharge hole 64 is at one end of the waste ink tray 60. FIG. 13B is a diagram illustrating the configuration of Experiment 2 of the present invention, and is a diagram illustrating the configuration when the position of the first ink discharge hole 64 is on the center side of the waste ink tray 60.

(Evaluation method)
When the position of the recording head 22 and the ink set to be used are changed according to the order of the drying viscosity, how many g of ink is deposited on the waste ink trays 60 and 60A after the experiment, and how much the accumulated ink amount is by experiment. Evaluate based on whether the number has increased.

As for the position of the recording head 22, as an example, the recording heads 22 are arranged in the order of ink having a high dry viscosity from the side closer to the first ink discharge holes 64 and 64A. In addition, as a comparative example, an experiment was performed on the recording heads 22 arranged in the reverse order.
Regarding the print density, when the print density is 1.2 for all colors, two types of ink sets were used, in which only Bk was 1.3 and the other colors were 1.0.

  The positions of the first ink discharge holes 64 and 64A will be described. For the example and the comparative example, an experiment was performed on two types of waste ink trays in which the positions of the first ink discharge holes 64 and 64A are on one end and the center side of the waste ink trays 60 and 60A.

  In the case where the position of the first ink discharge hole 64 is at one end of the waste ink tray 60, as shown in the configuration of Experiment 1 (described later) in FIG. 13A in the configuration described in the first embodiment, The positions where the four recording heads 22 can be arranged are sequentially from the first ink discharge hole 64 side (in order from the downstream side to the upstream side in the paper transport direction P), the first position D1, the second position D2, the second position. Assume that the third position D3 and the fourth position D4. At these positions D1 to D4, the recording head 22 that discharges ink having different dry viscosities is arranged.

  When the position of the first ink discharge hole 64A is on the center side of the waste ink tray 60A, in the configuration described in the second embodiment, as shown in the configuration of Experiment 2 (described later) in FIG. The positions at which the recording heads 22 can be arranged are defined as a first position E1, a second position E2, a third position E3, and a fourth position E4 in order from the downstream side to the upstream side in the paper transport direction P. At these positions E1 to E4, the recording head 22 that discharges ink having different dry viscosities is arranged.

  As an evaluation method, first, purge and wipe operations are performed 30 times continuously, and then the ink remaining on the waste ink tray and the waste ink tray is dried for 12 hours in a constant temperature bath at 60 ° C. The above purge / wipe and drying steps are repeated seven times as one cycle. At the end of each cycle, the total weight of the waste ink tray and the ink remaining on the waste ink tray is measured. By subtracting the tray weight from the total weight value, the amount of ink remaining on the waste ink tray at the end of each cycle is calculated.

Based on the weight of ink on the waste ink tray at the end of 7 cycles and the rate of increase in the accumulated ink from the end of 1 cycle to the end of 7 cycles, the ink accumulation prevention performance on the waste liquid tray was evaluated. Comparison is made when the position of the first ink discharge hole, the order of the heads, and the ink used are changed.
The increase rate of the deposited ink is obtained by the following equation.
Increase rate of accumulated ink [%] = {(Amount of accumulated ink at the end of the seventh cycle) / (Amount of accumulated ink at the end of the first cycle)} × 100

A method for evaluating the increase rate of the accumulated ink will be described.
The result of the increase rate in this experiment is classified as follows according to three patterns of less than 150%, 150% or more and less than 300%, and 300% or more. In the present invention, a desirable embodiment is when the increase rate is less than 150%.
When the increase rate is less than 150%, the accumulation amount is small, so the first ink discharge hole is not clogged, and there is no problem in fluidity.
When the increase rate is 150% or more and less than 300%, there is no problem with the fluidity on the waste ink tray, but the solidified ink may be clogged in the first ink discharge hole.
When the increase rate is 300% or more, there is a possibility that the ink solidified on the waste ink tray forms a wall and the ink does not flow to the first ink discharge hole.

(Experiment 1)
Experiment 1 was performed when the position of the first ink discharge hole 64 is at one end of the waste ink tray 60 as shown in FIG. 13A.
Table 5 below summarizes the conditions of the experiments conducted by changing the combination of ink sets and the position (order) of the recording heads 22, and patterns A, B, C, and D, respectively.
Patterns A and C are Embodiments 1 and 2 of the present invention, and the four recording heads 22 are arranged so that the first ink discharge hole 64 side is the highest and the lower the order.
Patterns B and D are Comparative Examples 1 and 2, and the four recording heads 22 are arranged such that the first ink discharge hole 64 side is the lowest and the highest.

(Result of Experiment 1)
The experimental results of Experiment 1 using the ink sets used in Patterns A to D are shown in Table 6 below.

(Experiment 2)
Experiment 2 was conducted when the position of the first ink discharge hole 64A was on the center side of the waste ink tray 60A as shown in FIG. 13B.
Table 7 below summarizes the conditions for the experiments conducted by changing the combination of the ink sets and the order of the recording heads, and the patterns were set as patterns E, F, G, and H, respectively.
Patterns E and G are Embodiments 3 and 4 of the present invention, in which the four recording heads 22 are arranged so that the first ink discharge hole 64A side is the highest and lower in order.
Patterns F and H are Comparative Examples 3 and 4, and the four recording heads 22 are arranged in such a manner that the first ink discharge hole 64A side is the lowest and becomes higher in order.

(Result of Experiment 2)
Table 8 below shows the experimental results using the ink sets used in patterns E to H.

(Summary of results of Experiment 1 and Experiment 2)
Comparison between Pattern A (Example 1: Ink increase rate 173.73%) and B (Comparative Example 1: Ink increase rate 339.17%) and Pattern E (Example 3: Ink increase rate 140.95%) ) And F (Comparative Example 3: Ink increase rate 313.07%), the heads arranged in descending order of the dry viscosity from the side closer to the first ink discharge hole were discarded than the ones arranged in reverse. It has been found that the amount of ink remaining on the ink tray and the amount of increase are reduced.
By comparing the pattern A (Example 1: ink increase rate 173.73%) and C (Example 2: ink increase rate 144.41%), the print density is (Bk1.3, other color 1.0). It was found that the amount of ink remaining on the waste ink tray and the amount of increase were smaller in the combination of (2) than in the combination of (all colors 1.2).
By comparing Pattern A (Example 1: Ink increase rate 173.73%) and E (Example 3: Ink increase rate 140.95%), the one with the first ink discharge hole on the center side is the end. It has been found that the amount of ink remaining on the waste ink tray and the amount of increase are less than in the case of the above.
In the condition of pattern G (Example 4: ink set having a Bk density of 1.3, ink having a high dry viscosity on the first ink discharge hole side, and the first ink discharge hole on the center side), the ink accumulation amount was the smallest.

  Further, according to the results of Experiment 1 and Experiment 2, the dry viscosity of both the first ink discharge hole is at the end of the waste ink tray and the first ink discharge hole is at the center of the waste ink tray. It has been found that the amount of ink deposited on the waste ink tray can be reduced by placing high ink near the first ink discharge holes. Therefore, the present invention can also be applied to waste ink trays having different first ink discharge holes.

(Experiment 3)
Next, an experiment was conducted in the case where an ink having a drying rate of 45% and an ink having a dry viscosity outside the predetermined viscosity range was used. The case where the drying rate is within a predetermined viscosity value range of 45% of the ink means that the viscosity of the ink having the highest drying viscosity at a drying rate of 45% is in the range of 180 mPa · s or more and less than 250 mPa · s. Or the viscosity of the ink having the lowest drying viscosity at a drying rate of 45% is in the range of 60 mPa · s or more and less than 130 mPa · s.

When it was out of this range, an experiment was conducted under the following four conditions, and patterns I, J, K, and L were set, respectively.
As an ink set to be compared, a pattern G which is the best embodiment was used, and the position of the first ink discharge hole and the order of the recording head were the same as those of the pattern G. The ink was changed one by one in accordance with the determined conditions, and the same ink was used for the other three.

For pattern I, an ink (Bk3, 253 mPa · s) having a higher viscosity than the range of 180 mPa · s or more and less than 250 mPa · s was used for the ink having the highest dry viscosity.
For pattern J, an ink (Bk4, 177 mPa · s) having a lower viscosity than the range of 180 mPa · s or more and less than 250 mPa · s was used for the ink having the highest dry viscosity.
For pattern K, an ink (Y3, 132 mPa · s) having a viscosity higher than the range of 60 mPa · s or more and less than 130 mPa · s was used for the ink having the lowest dry viscosity.
For pattern L, an ink (Y4, 59 mPa · s) having a lower viscosity than the range of 60 mPa · s or more and less than 130 mPa · s was used for the ink having the lowest dry viscosity.

  The patterns I to L in this experiment and the pattern G to be compared are summarized in Table 9 below.

(Result of Experiment 3)
The experimental results using the ink sets used in patterns G and I to L are shown in Table 10 below.

With respect to the pattern I, the increase amount of the ink on the waste ink tray exceeds 150% (229.36%), so that the object of the present invention is not achieved.
For the pattern J, the printing density of the Bk ink is less than the prescribed density of the ink set in the present invention (1.3 is required for this ink set, but 1.27), so the object in the present invention is not achieved.
With respect to the pattern K, the increase amount of the ink on the waste ink tray exceeds 150% (165.19%), so that the object of the present invention is not achieved.
For the pattern L, the printing density of Y ink is less than the specified density of the ink set in the present invention (1.0 is necessary for this ink set, but 0.96), and therefore the object in the present invention is not achieved.

(Summary of results of Experiment 3)
From the above results, a predetermined viscosity value range with a drying rate of 45% (the highest ink with a drying rate of 45% has an ink viscosity of 180 mPa · s to less than 250 mPa · s, and the lowest ink viscosity of 60 mPa · s). It was confirmed that when the ink outside the range of s to less than 130 mPa · s was used, the object of the present invention could not be achieved with respect to the ink accumulation amount or the print density.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet recording apparatus, 22 (Y, K, C, M) ... Recording head, 60, 60A, 60B, 60C, 60D, 60E ... Waste ink tray (waste liquid tray), 62, 62A ... 1st Ink guide inclined part (inclined part), 68, 68A ... 2nd valley inclined part (inclined part), 64, 64A, 64B, 64C ... First ink discharge hole (ink discharge part), 623 ... groove

Claims (5)

A plurality of recording heads for ejecting ink;
A waste liquid tray for receiving ink ejected from the plurality of recording heads, an ink discharge portion for discharging the ink to the outside of the waste liquid tray; and the ink received and received below the plurality of recording heads A waste liquid tray having an inclined portion that is inclined so as to be guided to the ink discharge portion,
Among the plurality of recording heads, a recording head that discharges ink having a high drying viscosity, which is the viscosity of the ink when the ink drying rate is the same, has a lower ink discharge unit than the recording head that discharges ink having a low drying viscosity. Placed nearby ,
Wherein the inclined portion is an ink jet recording apparatus in which a plurality of grooves Ru is formed to extend along the direction in which the plurality of recording heads are arranged. The plurality of recording heads are arranged in order of a recording head that discharges ink having a high dry viscosity and a recording head that discharges ink having a low dry viscosity as it goes away from a side closer to the ink discharge unit. The ink jet recording apparatus according to claim 1. The ink discharge portion is disposed on an end portion side in the direction in which the plurality of recording heads are arranged in the waste liquid tray,
3. The ink jet recording apparatus according to claim 1, wherein the inclined portion is inclined so as to be directed downward toward the ink discharge portion in a direction in which the plurality of recording heads are arranged. The ink discharge portion is disposed on the center side in the direction in which the plurality of recording heads are arranged in the waste liquid tray,
3. The ink jet recording apparatus according to claim 1, wherein the inclined portion is inclined so as to be directed downward toward the ink discharge portion in a direction in which the plurality of recording heads are arranged. Drying viscosity of the ink when dry rate is 45% of the ink-jet recording apparatus according to any one of claims 1 to 4 is less than 250 mPa · s.

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