JP2016198882A - Inkjet recording device - Google Patents

Abstract

An ink jet recording apparatus capable of suppressing the occurrence of image defects by suppressing the recording medium from being influenced by a second transport unit on a first transport unit.
A printer (inkjet recording apparatus) includes a first transport unit 30 and a second transport unit 40 that suck and transport paper S. The 1st conveyance unit 30 contains the 1st conveyance belt 33 in which the 1st through-hole was formed, and the 1st suction part 34 in which the 1st suction port 35a was provided. The 2nd conveyance unit 40 contains the 2nd conveyance belt 43 in which the 2nd through-hole was formed, and the 2nd suction part 44 provided with the 2nd suction port 45a. When the paper S is straddling the first transport unit 30 and the second transport unit 40, the suction force of the first transport unit 30 with respect to the paper S is larger than the suction force of the second transport unit 40 with respect to the paper S.
[Selection] Figure 2

Description

  The present invention relates to an ink jet recording apparatus including a first transport unit and a second transport unit that suck and transport paper (recording medium).

  2. Description of the Related Art Conventionally, a first transport unit that is disposed below a recording head and sucks and transports paper and a second transport unit that is disposed on the downstream side of the first transport unit in the paper transport direction and sucks and transports paper are provided. Inkjet recording apparatuses are known. In such an ink jet recording apparatus, the first transport unit and the second transport unit are disposed inside the transport belt having a through-hole formed for adsorbing and transporting the paper, and the paper is transported to the transport belt. And a suction part for sucking air to be adsorbed on.

  Note that an ink jet recording apparatus including a first transport unit that is disposed below the recording head and sucks and transports paper is disclosed in, for example, Patent Document 1 and Patent Document 2.

Japanese Patent Laid-Open No. 9-220837 JP 2003-118908 A

  However, in the conventional inkjet recording apparatus including the first transport unit and the second transport unit, when the paper is transported from the first transport unit to the second transport unit, the paper is transported from the first transport unit and the second transport unit. It will be in a state straddling. In this state, if the suction force of the second transport unit with respect to one sheet of paper straddled is larger than the suction force of the first transport unit, an image defect may occur. Specifically, when the transport speed of the second transport unit is higher than the transport speed of the first transport unit, the paper is pulled by the second transport unit, and the transport speed of the second transport unit is the transport speed of the first transport unit. When the speed is smaller than the speed, the recording medium bends between the first transport unit and the second transport unit. For this reason, an image defect may occur.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to suppress the recording medium from being affected by the second transport unit on the first transport unit, An object of the present invention is to provide an ink jet recording apparatus capable of suppressing the occurrence of image defects.

  In order to achieve the above object, an ink jet recording apparatus according to a first configuration of the present invention includes a recording head that ejects ink onto a recording medium, and a lower part of the recording head that adsorbs and conveys the recording medium. And a second transport unit that is disposed downstream of the first transport unit in the recording medium transport direction and sucks and transports the recording medium. The first transport unit is disposed inside the first transport belt and an endless first transport belt formed with a plurality of first through holes, and sucks air to adsorb the recording medium to the first transport belt. A first suction section provided with a first suction port, and the second transport unit includes an endless second transport belt in which a plurality of second through holes are formed, and an inner side of the second transport belt. And a second suction part provided with a second suction port for sucking air to adsorb the recording medium to the second transport belt, and the first transport unit and the second transport unit have the recording medium When straddling the first transport unit and the second transport unit, the suction force of the first transport unit with respect to the recording medium is configured to be larger than the suction force of the second transport unit with respect to the recording medium. The suction port is from the first suction port It is arranged at a minimum size length than the length of the recording medium in the recording medium conveying direction.

  According to the first configuration of the present invention, it is possible to suppress the occurrence of image defects by suppressing the recording medium from being affected by the second transport unit on the first transport unit.

1 is a diagram illustrating a structure of a printer according to a first embodiment of the present invention. FIG. 2 is a diagram illustrating a structure around a recording unit, a first transport unit, and a second transport unit of the printer of FIG. 1. FIG. 2 is a diagram of a first transport unit and a recording unit of the printer of FIG. 1 viewed from above. It is the figure which looked at the recording part of the printer of FIG. 1 from diagonally upward. FIG. 2 is a diagram illustrating a recording head constituting a line head of a recording unit of the printer of FIG. 1. FIG. 2 is a diagram of the recording head of the printer of FIG. 1 viewed from the ink ejection surface side. FIG. 3 is a diagram of a first transport unit and a second transport unit of the printer of FIG. 1 viewed from above. It is the figure which looked at the 1st conveyance unit and the 2nd conveyance unit of the printer of a 2nd embodiment of the present invention from the upper part.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
An ink jet printer 100 (ink jet recording apparatus) according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the printer 100 has a paper feed cassette 2 that is a paper storage unit disposed below the inside of the printer main body 1. A sheet S, which is an example of a recording medium, is accommodated inside the sheet feed cassette 2. A paper feeding device 3 is disposed downstream of the paper feeding cassette 2 in the paper conveyance direction, that is, above the right side of the paper feeding cassette 2 in FIG. The paper feeding device 3 separates and feeds the paper S one by one toward the upper right of the paper feeding cassette 2 in FIG.

  Further, the printer 100 includes a first paper transport path 4a therein. The first paper transport path 4a is located at the upper right, which is the paper feed direction in the paper feed cassette 2. The paper S sent out from the paper feed cassette 2 is transported vertically upward along the side surface of the printer main body 1 by the first paper transport path 4a.

  A registration roller pair 13 is provided at the downstream end of the first paper transport path 4a with respect to the paper transport direction. Further, a first transport unit 30 and a recording unit 9 are disposed in the immediate vicinity of the registration roller pair 13 on the downstream side in the paper transport direction. The paper S sent out from the paper feed cassette 2 reaches the registration roller pair 13 through the first paper transport path 4a. The registration roller pair 13 corrects the oblique feeding of the paper S and measures the timing of the ink ejection operation performed by the recording unit 9 and sends the paper S toward the first transport unit 30.

  As shown in FIG. 2, the recording unit 9 includes line heads 11 </ b> C, 11 </ b> M, 11 </ b> Y, and 11 </ b> K that record images on the paper S that is sucked and held by the first transport unit 30 and transported. Corresponding to the information of the image data received from an external computer or the like, the paper S is sequentially ejected from each of the line heads 11C to 11K toward the paper S attracted to the first transport belt 33 described later. A full-color image in which four colors of yellow, magenta, cyan, and black are superimposed is recorded.

  A second transport unit 40 is disposed on the downstream side (left side in FIG. 1) of the first transport unit 30 with respect to the paper transport direction. The paper S on which the ink image is recorded by the recording unit 9 is sent to the second transport unit 40, and the ink ejected on the surface of the paper S while passing through the second transport unit 40 is dried.

  As shown in FIG. 1, a decurler unit 14 is provided on the downstream side of the second transport unit 40 in the paper transport direction and in the vicinity of the left side surface of the printer body 1. The paper S on which the ink has been dried by the second transport unit 40 is sent to the decurler unit 14, and the curl generated on the paper S is corrected.

  A second paper transport path 4b is provided on the downstream side (upper side in FIG. 1) of the decurler unit 14 with respect to the paper transport direction. When the double-sided recording is not performed, the paper S that has passed through the decurler unit 14 is discharged from the second paper conveyance path 4b to a paper discharge tray 15 provided outside the left side surface of the printer 100.

  A maintenance unit 19 is disposed below the second transport unit 40. The maintenance unit 19 moves below the recording unit 9 when purging, wipes ink ejected from ejection nozzles 18 (see FIG. 3) of recording heads 17a to 17c, which will be described later, and removes the wiped ink. to recover.

  A reverse conveyance path 16 for performing double-sided recording is provided above the printer body 1 and above the recording unit 9 and the second conveyance unit 40. When performing double-sided recording, the recording on the first surface and the paper S that has passed through the second transport unit 40 and the decurler unit 14 are sent to the reverse transport path 16 through the second paper transport path 4b. The paper S sent to the reverse conveyance path 16 is subsequently switched in the conveyance direction for recording on the second side, passes through the upper part of the printer main body 1 and is sent to the right side, and the first paper conveyance path 4a. , And the registration roller pair 13, and the second surface is sent again to the first transport unit 30 with the second surface facing upward.

  As shown in FIGS. 3 and 4, the recording unit 9 includes a head housing 10 and line heads 11 </ b> C, 11 </ b> M, 11 </ b> Y, and 11 </ b> K held by the head housing 10. These line heads 11 </ b> C to 11 </ b> K are supported at such a height that a predetermined interval (for example, 1 mm) is formed with respect to a conveyance surface 33 a of the first conveyance belt 33 to be described later, and a sheet width perpendicular to the sheet conveyance direction. A plurality (three in this case) of recording heads 17a to 17c are arranged in a staggered manner along the direction (vertical direction in FIG. 3).

  As shown in FIGS. 5 and 6, a nozzle region R in which a large number of ejection nozzles 18 (see FIG. 3) are arranged is provided on the ink ejection surfaces F of the recording heads 17a to 17c. Since the recording heads 17a to 17c have the same shape and configuration, the recording heads 17a to 17c are shown in one drawing in FIGS.

  In the recording heads 17a to 17c constituting the line heads 11C to 11K, inks of four colors (cyan, magenta, yellow, and black) stored in ink tanks (not shown) are respectively stored in the line heads 11C to 11K. Supplied for each color.

  Each of the recording heads 17a to 17c discharges ink from the discharge nozzle 18 toward the paper S that is sucked and held by a first transport belt 33 (to be described later) in accordance with image data received from an external computer or the like. As a result, a color image in which four colors of cyan, magenta, yellow, and black are superimposed is formed on the sheet S on the first transport belt 33.

  Next, a detailed structure around the first transport unit 30 and the second transport unit 40 will be described.

  As shown in FIG. 2, the first transport unit 30 includes an endless first transport belt 33 that is wound around a first drive roller 31 and a first driven roller 32. The first conveyor belt 33 is rotated counterclockwise in FIG. 2 by the first drive roller 31. The sheet S sent out by the registration roller pair 13 is sucked and held on the transport surface 33a (upper surface in FIG. 2) of the first transport belt 33, and is transported in the arrow X direction (right to left) in FIG.

  A first suction unit 34 is provided at a location inside the first transport belt 33 and facing the back side of the transport surface 33 a of the first transport belt 33. The first suction part 34 has a first duct 35 provided with a plurality of first suction ports 35a (see FIG. 7) for air suction on the upper surface, and discharges the air in the first duct 35 to the outside for the first duct. And a fan 36 that makes the inside of the space 35 a negative pressure space. Air can be sucked downward from the upper surface. The first transport belt 33 is provided with a number of first through holes 33b for air suction (see FIG. 7). With the above configuration, the first transport unit 30 transports the sheet S while adsorbing and holding the sheet S on the transport surface 33 a of the first transport belt 33. The upper surface of the first duct 35 functions as a conveyance guide that supports the inner surface of the first conveyance belt 33.

  The second transport unit 40 includes an endless second transport belt 43 wound around a second drive roller 41 and a second driven roller 42. The second conveyor belt 43 is rotated counterclockwise in FIG. 2 by the second drive roller 41. The sheet S on which an image is recorded by the recording unit 9 and conveyed in the direction of the arrow X by the first conveyance unit 30 is transferred to the second conveyance belt 43 and conveyed on the conveyance surface 43a (upper surface in FIG. 2) of the second conveyance belt 43. And is conveyed in the direction of arrow Z in FIG.

  A second suction portion 44 is provided at a location inside the second transport belt 43 and facing the back side of the transport surface 43 a of the second transport belt 43. The second suction part 44 has a second duct 45 provided with a plurality of second suction ports 45a (see FIG. 7) for air suction on the upper surface, and discharges the air in the second duct 45 to the outside to discharge the second duct. And a fan 46 that makes the inside of the space 45 a negative pressure space. Air can be sucked downward from the upper surface. The second conveyor belt 43 is provided with a number of second through holes 43b (see FIG. 7) for air suction. With the above configuration, the second transport unit 40 transports the sheet S while adsorbing and holding the sheet S on the transport surface 43 a of the second transport belt 43. The upper surface of the second duct 45 functions as a conveyance guide that supports the inner surface of the second conveyance belt 43.

  As shown in FIG. 7, the plurality of first suction ports 35 a of the first transport unit 30 are formed over substantially the entire upper surface of the first duct 35, while the plurality of second suction ports of the second transport unit 40. 45a is formed only on a part of the upper surface of the second duct 45 (here, the portion on the left side (downstream in the transport direction)).

  7 indicates the most upstream end of the first suction port 35a, the position P2 indicates the most downstream end of the first suction port 35a, and the suction action of the first duct 35 is the position from the position P1. It affects the area up to P2. The recording heads 17a to 17c are disposed inside a facing area that faces the area from the position P1 to the position P2. The position P3 indicates the most upstream end of the second suction port 45a, the position P4 indicates the most downstream end of the second suction port 45a, and the suction action of the second duct 45 is from the position P3 to the position P4. Act on the area.

  Here, in the present embodiment, when the sheet S straddles the first transport unit 30 and the second transport unit 40, the first transport unit 30 and the second transport unit 40 apply to one sheet S straddled. The suction force of the first transport unit 30 is configured to be always greater than the suction force of the second transport unit 40.

  In order to realize this, for example, the output of the fan 36 may be configured to be larger than the output of the fan 46. More fans 36 may be installed than fans 46. The diameter of the first through hole 33b may be formed larger than the diameter of the second through hole 43b. The first through holes 33b may be formed so that the number per unit area is larger than that of the second through holes 43b. The first suction port 35a may be formed larger than the second suction port 45a (for example, at least one of the length in the paper transport direction and the length in the paper width direction is larger). The number of first suction ports 35a (here, nine) may be formed to be larger than the number of second suction ports 45a (here, three).

  In addition, the second suction port 45a is disposed at a distance L1 that is greater than or equal to the length of the minimum size paper S in the paper transport direction from the most downstream end (position P2) of the first suction port 35a.

  As shown in FIG. 1, the decurler unit 14 disposed downstream of the second transport unit 40 in the paper transport direction nips and transports the paper S between the correction roller (transport roller) 14a and the correction roller 14a. And a third driving roller 14c and a third driven roller 14d around which the correction belt 14b is wound. The nip portion between the correction roller 14a and the correction belt 14b is disposed at a distance less than the length of the maximum size sheet S in the sheet conveyance direction from the most downstream end (position P2) of the first suction port 35a. ing.

  In the present embodiment, as described above, the first transport unit 30 and the second transport unit 40 perform the first transport on the paper S when the paper S straddles the first transport unit 30 and the second transport unit 40. The unit 30 is configured such that the suction force of the second transport unit 40 with respect to the paper S is greater. Thereby, before the printing operation by the recording heads 17a to 17c is completed, the sheet S can be prevented from being pulled or bent due to the influence of the second transport unit 40. For this reason, it is possible to suppress the occurrence of image defects.

  If the suction force of the second transport unit 40 with respect to the paper S is greater than the suction force of the first transport unit 30 with respect to the paper S, the transport speed of the second transport unit 40 is greater than the transport speed of the first transport unit 30. In this case, the sheet S is pulled by the second transport unit 40. On the other hand, when the transport speed of the second transport unit 40 is lower than the transport speed of the first transport unit 30, the sheet S bends between the first transport unit 30 and the second transport unit 40. For this reason, an image defect may occur.

  Further, the second suction port 45a is disposed at a distance L1 that is equal to or longer than the length of the minimum size paper S in the paper transport direction from the first suction port 35a. Accordingly, when the paper S of the minimum size is transported in the paper transport direction, the front end of the paper S is sucked by the second transport unit 40 while the rear end of the paper S is sucked by the first transport unit 30. Can be prevented. For this reason, before the printing operation by the recording heads 17a to 17c is completed, it is possible to prevent the sheet S from being affected by the second transport unit 40 and causing an image defect. When the paper S is a small size, in the final phase of the paper conveyance by the first conveyance unit 30 (only the rear end portion of the paper S is positioned on the first conveyance unit 30), the first conveyance unit The adsorption power of 30 is small. This embodiment is particularly effective because it is possible to suppress the influence of the second transport unit 40 in that state (a state where the suction force of the first transport unit 30 is small).

  Further, as described above, the correction roller 14a disposed on the downstream side in the sheet conveyance direction of the second conveyance unit 40 and the correction belt 14b that nips and conveys the sheet S between the correction roller 14a are provided. As a result, the paper S can be transported with a smaller nip pressure than when the paper S is nipped and transported using the transport roller pair. For this reason, even when the ink of the paper S that has passed through the second transport unit 40 is not sufficiently dried, it is possible to suppress the deterioration of the image.

  Further, the nip portion between the correction roller 14a and the correction belt 14b is arranged at a distance less than the length of the maximum size paper S in the paper transport direction from the first suction port 35a. Thus, when the maximum size paper S is transported, the front end portion side of the paper S is in the state where the rear end portion of the paper S is adsorbed by the first transport unit 30, and the correction roller 14 a and the correction belt 14 b. And nipped by. In the final phase of the sheet conveyance by the first conveyance unit 30 (a state where only the rear end portion of the sheet S is positioned on the first conveyance unit 30), the suction force of the first conveyance unit 30 is small. In the present embodiment, the portion on the front end side of the sheet S is nipped by the correction roller 14a and the correction belt 14b, so that the state of the second conveyance unit 40 in that state (the state where the suction force of the first conveyance unit 30 is small). Since it can suppress being influenced, it is especially effective.

(Second Embodiment)
In the printer 100 according to the second embodiment of the present invention, as illustrated in FIG. 8, the first suction port 35 a is disposed in a passage region Q through which the smallest size paper S passes in the paper width direction. That is, the first suction port 35a is not formed outside the passage region Q.

  Further, the second suction port 45a is disposed in the passage region Q, like the first suction port 35a. That is, the second suction port 45a is not formed outside the passage region Q.

  Other structures of the second embodiment are the same as those of the first embodiment.

  In the present embodiment, as described above, the first suction port 35a is disposed in the passage area Q through which the paper S of the minimum size passes in the paper width direction. Thereby, it is possible to prevent the suction force of the first suction part 34 from being wasted even when the paper S of any size is transported.

  Further, as described above, the second suction port 45a is disposed in the passage area Q through which the paper S of the minimum size passes in the paper width direction. Accordingly, it is possible to prevent the suction force of the second suction unit 44 from being wasted even when the paper S of any size is transported.

  Other effects of the second embodiment are the same as those of the first embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above-described embodiment, an example has been described in which the upper surface of the first duct 35 and the upper surface of the second duct 45 function as a conveyance guide that supports the inner surface of the first conveyance belt 33 and the inner surface of the second conveyance belt 43, respectively. The present invention is not limited to this. A transport guide that supports the inner surface of the first transport belt 33 and the inner surface of the second transport belt 43 is provided separately from the first duct 35 and the second duct 45, and a first suction port for air suction is provided in the transport guide. A second suction port may be provided.

14a Straightening roller (conveyance roller)
14b Straightening belt (third conveyor belt)
17a to 17c Recording head 30 1st conveyance unit 33 1st conveyance belt 33b 1st through-hole 34 1st suction part 35a 1st suction port 40 2nd conveyance unit 43 2nd conveyance belt 43b 2nd through-hole 44 2nd suction part 45a Second suction port 100 Printer (ink jet recording apparatus)
L1 Distance Q Passing area S Paper (recording medium)

Claims (4)

A recording head for discharging ink onto the recording medium;
A first transport unit that is disposed below the recording head and sucks and transports the recording medium;
A second transport unit that is disposed downstream of the first transport unit in the recording medium transport direction and sucks and transports the recording medium;
With
The first transport unit is disposed inside the first transport belt and an endless first transport belt in which a plurality of first through holes are formed, and for adsorbing the recording medium to the first transport belt. And a first suction part provided with a first suction port for sucking air,
The second transport unit is disposed inside an endless second transport belt in which a plurality of second through holes are formed, and inside the second transport belt, so as to attract the recording medium to the second transport belt. A second suction part provided with a second suction port for sucking air,
In the first transport unit and the second transport unit, when the recording medium straddles the first transport unit and the second transport unit, the adsorption force of the first transport unit with respect to the recording medium is the recording medium. It is comprised so that it may become larger than the adsorption power of the 2nd conveyance unit to a medium,
The ink jet recording apparatus, wherein the second suction port is disposed at a distance from the first suction port by a distance equal to or longer than a length of a minimum size recording medium in a recording medium conveyance direction.   2. The ink jet recording apparatus according to claim 1, wherein the second suction port is disposed in a passage region through which a recording medium of a minimum size passes in a recording medium width direction orthogonal to the recording medium conveyance direction. .   3. The inkjet according to claim 1, wherein the first suction port is disposed in a passage region through which a recording medium of a minimum size passes in a recording medium width direction orthogonal to the recording medium conveyance direction. Recording device. A transport roller disposed downstream of the second transport unit in the recording medium transport direction;
A third conveying belt that nips and conveys the recording medium with the conveying roller;
With
The nip portion between the transport roller and the third transport belt is disposed at a distance from the first suction port that is less than the length of the maximum size recording medium in the recording medium transport direction. The inkjet recording apparatus according to any one of claims 1 to 3.

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