JP2012016958A - Inkjet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording apparatus for printing an image on a recording medium in which foreign substances do not tend to adhere to a recording head.SOLUTION: An inkjet printer 1 includes an inkjet head 2a for monochrome, three inkjet heads 2b for color, a conveying mechanism 40 which defines a conveyance path including positions opposed to the heads 2a and 2b, and a bypass conveying mechanism 60. The conveying mechanism 40 has a first unit 41 and a second unit 51. The bypass conveying mechanism 60 defines a bypass path that is connected at a position between the first and second units 41 and 51, for permitting paper P to be conveyed so as to bypass the position where the paper P is opposed to the head 2b.

Description

  The present invention relates to an ink jet recording apparatus that prints an image on a recording medium.

  Patent Document 1 describes an ink jet printer including four ink jet heads that eject magenta, cyan, yellow, and black inks, and a maintenance unit that performs maintenance of these heads. In this inkjet printer, when performing maintenance of the inkjet head, first, the four inkjet heads are raised from the printing position to the head maintenance position, and the ink is purged from the four inkjet heads to the tray. Thereafter, the ink attached to the ejection surface of each head is wiped with a wiper, whereby the maintenance of the inkjet head is completed.

JP 2008-213202 A

  In the ink jet printer described in Patent Document 1, even when a monochrome image is printed on a sheet, the sheet passes through a position facing the color head. For this reason, foreign matter such as paper dust also moves in the vicinity of the discharge surface (for example, nozzle) of the color head that does not contribute to printing, and the foreign matter tends to adhere to the nozzle. For this reason, it is necessary to maintain all the heads, and as a result, there arises a problem that the ink consumption due to the maintenance cannot be suppressed.

  Accordingly, an object of the present invention is to provide an ink jet recording apparatus that makes it difficult for foreign matter to adhere to the recording head.

  The inkjet recording apparatus of the present invention includes first and second recording heads each having an ejection port for ejecting ink, a first position facing the ejection port of the first recording head, and the ejection of the second recording head. A transport mechanism that defines a transport path of the recording medium including a second position facing the exit, and the first position and the second position so that the recording medium is transported around the second position. And a detour conveyance mechanism that defines a detour path connected to the conveyance path.

  According to this, when printing is performed on the recording medium only by ink ejection from the first recording head, the recording medium can be transported through the recording medium to the detour path so that the recording medium is transported while bypassing the second position. Become. This makes it difficult for foreign matter (dust such as paper dust) to adhere to the second recording head. As a result, ink consumption due to maintenance of the second recording head can be suppressed.

  In the present invention, the transport mechanism includes a transport belt that faces the second recording head and transports the recording medium to the second position. An annular cap disposed around the second recording head so as to surround the second recording head, and a position where the cap is in close contact with the conveying belt and a position where the cap is separated from the conveying belt. It is preferable to further include a cap mechanism having a moving mechanism for moving the cap. Accordingly, the external space that communicates with the ejection port of the second recording head can be made a sealed space (that is, capped) by moving the cap to a position where it is in close contact with the transport belt. For this reason, it is possible to suppress the viscosity of the ink in the vicinity of the ejection port from increasing. In addition, it is not necessary to move the second recording head when capping the second recording head. For this reason, it is not necessary to secure a space for moving the second recording head, the apparatus main body can be downsized, and the configuration of the moving mechanism is simpler than the mechanism for moving the second recording head. Become.

  In the present invention, between the position where the sealed space is formed with the cap and the surface of the second recording head on which the discharge port is formed as a part of the inner wall surface, and the position where the sealed space is not formed. 2 further includes a cap mechanism having a moving mechanism for moving the cap, and a distribution unit that distributes the recording medium to either the transport path or the detour path. When the sorting unit directs the recording medium to the detour path, the cap is preferably disposed at a position where the sealed space is formed. As a result, when the recording medium is directed to the detour path, the external space leading to the ejection port of the second recording head can be a sealed space. For this reason, it is possible to suppress the viscosity of the ink in the vicinity of the ejection opening of the second recording head from increasing.

  In the present invention, the transport path is defined by the transport mechanism so that the first and second positions are horizontally aligned along the transport direction of the recording medium, and upstream of the transport mechanism, It is preferable that a registration roller for correcting the skew of the recording medium is provided. Thereby, since the first and second positions are arranged horizontally, skewing is unlikely to occur between the first position and the second position. Therefore, it is not necessary to provide another registration roller between the first and second positions.

  The present invention further includes a reverse transport mechanism that reverses the recording medium transported by the transport mechanism or the detour transport mechanism and defines a retransmission path for retransmission to the transport mechanism. And it is preferable that the said reverse conveyance mechanism and the said detour conveyance mechanism share a part of mutual path | route. Thereby, even if the reverse conveyance mechanism and the detour conveyance mechanism are provided, the apparatus configuration is simplified by sharing a part of the both paths.

  In the present invention, it is preferable that the first recording head ejects black ink, and the second recording head ejects color ink other than black ink. Accordingly, the black ink is ejected from the first recording head and the color ink is ejected from the second recording head.

  In the present invention, each of the first and second recording heads has an ejection region in which a plurality of ejection ports are formed, and the ejection region is related to a direction perpendicular to the conveyance direction of the recording medium. The recording medium preferably has a length equal to or longer than the length of the recording medium. This makes it possible to print on the recording medium without moving the first and second recording heads in the direction orthogonal to the transport direction.

  In the present invention, it is preferable that the first and second recording heads, the transport mechanism, and the detour transport mechanism are arranged in one direction. Thereby, it becomes an apparatus configuration in which the first and second recording heads, the transport mechanism, and the detour transport mechanism are arranged in one direction.

  Further, in the present invention, one or more recording media can be accommodated, and a sheet feeding unit that supplies the recording medium to the transport mechanism or the bypass transport mechanism; and at least one of the transport mechanism and the bypass transport mechanism And a paper discharge unit that accommodates the conveyed recording medium. Preferably, the paper discharge unit, the first and second recording heads, the transport mechanism, the detour transport mechanism, and the paper feed unit are arranged in the one direction. As a result, an apparatus configuration in which the paper discharge unit, the first and second recording heads, the transport mechanism, the detour transport mechanism, and the paper feed unit are arranged in one direction.

  In the present invention, the first recording head discharges black ink, the second recording head discharges color ink other than black ink, and performs maintenance for recovering the discharge of the first and second recording heads. The apparatus further includes a maintenance unit and a control unit that controls the maintenance unit. The control unit controls the maintenance unit to perform maintenance of the first and second recording heads after printing a color image on a recording medium, and prints the first recording after printing a monochrome image on the recording medium. It is preferable to control the maintenance unit so that only the head is maintained. Thereby, when a monochrome image is printed on the recording medium, ink consumption due to maintenance of the second recording head is not performed, so that it is possible to more reliably suppress ink consumption.

  In the present invention, the transport path is defined by the transport mechanism so that the first and second positions are arranged in order along the transport direction of the recording medium, and the bypass path is defined by the first and second paths. It is preferable to branch from the transport path between two positions and join the transport path downstream of the second position.

  In the present invention, the image forming apparatus further includes a paper discharge unit that stores the recording medium conveyed from the conveyance mechanism. The transport path is defined by the transport mechanism so that the first and second positions are arranged in order along the transport direction of the recording medium, and the bypass path is between the first and second positions. In this case, it is preferable to branch from the transport path and connect to the paper discharge unit.

  In the present invention, the image forming apparatus further includes a paper feeding unit that can store one or more recording media and supplies the recording media to the transport mechanism. The transport path is defined by the transport mechanism so that the second and first positions are arranged in order along the transport direction of the recording medium, and the bypass path extends from the paper feeding unit to the transport path. It is preferable to branch from a path connected to the upstream and join the transport path between the first and second positions.

  According to the ink jet recording apparatus of the present invention, when printing is performed on the recording medium only by ink ejection from the first recording head, the recording medium is transported through the detour path so that the recording medium is detoured to the second position. It becomes possible to do. This makes it difficult for foreign matter (dust such as paper dust) to adhere to the second recording head. As a result, ink consumption due to maintenance of the second recording head can be suppressed.

1 is a schematic side view showing an internal structure of an ink jet printer according to a first embodiment of the present invention. It is a top view of four inkjet heads, a conveyance mechanism, and a maintenance unit which are shown in FIG. FIG. 2 is a partial side view of the ink jet printer shown in FIG. 1, (a) is a situation diagram showing a state where four ink jet heads are not capped by a maintenance unit, and (b) is a situation where four ink jet heads are capped by a maintenance unit. It is a situation figure which shows the state made. FIG. 2 is a partial side view of the ink jet printer shown in FIG. 1, and is a situation diagram showing a state where three ink jet heads on the downstream side are capped by a maintenance unit. It is a schematic side view which shows the internal structure of the inkjet printer by 2nd Embodiment of this invention. It is a schematic side view which shows the internal structure of the inkjet printer by 3rd Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
As shown in FIG. 1, the ink jet printer 1 according to the first embodiment of the present invention has a rectangular parallelepiped casing 1a, and a paper discharge unit 5 is provided on the top thereof. The inside of the housing 1a is divided into two spaces A and B in order from the top. In the space A, a monochrome inkjet head (first recording head) 2a that discharges black ink is arranged in parallel along the sub-scanning direction with the head 2a, and discharges magenta, cyan, and yellow inks 3 respectively. Two color ink-jet heads (second recording heads) 2b are arranged. In the space A, a transport mechanism 40, a detour transport mechanism 60, and a retransmission mechanism (reverse transport mechanism) 70 are sequentially disposed below the heads 2a and 2b. In the space B, a paper feeding unit (paper feeding unit) 10 is arranged. Furthermore, the inkjet printer 1 includes a control unit 100 that controls these operations.

  As shown in FIGS. 1 and 2, the four inkjet heads 2 a and 2 b have a substantially rectangular parallelepiped shape that is long in the main scanning direction. That is, the ink jet printer 1 is a line printer. In the present embodiment, the sub-scanning direction is a direction parallel to the conveyance direction C of the paper P, and the main scanning direction is a direction perpendicular to the sub-scanning direction and along the horizontal plane.

  The inkjet head 2 has a laminated body (both not shown) in which a flow path unit in which an ink flow path including a pressure chamber is formed and an actuator that applies pressure to ink in the pressure chamber are bonded together. Are the ejection surfaces 3a and 3b for ejecting ink. On the discharge surfaces 3a and 3b, discharge regions 4b including a plurality of discharge ports 4a for discharging ink are formed. The ejection region 4b is formed slightly longer than the paper P in the main scanning direction, and an image can be formed on the entire surface of the paper P (marginless printing).

  Inside the ink jet printer 1, a printing path, a retransmission path, and a bypass path for monochrome printing are formed. The print path is a path along which the paper P is transported along the thick arrow (black arrow) shown in FIG. 1 and passes from the paper supply unit 10 to the paper discharge unit 5 through the transport path defined by the transport mechanism 40. This is the path to go. The conveyance path here is a path between the four inkjet heads 2a, 2b and the conveyance mechanism 40 and is a substantially linear path extending along the sub-scanning direction. The detour path is a path defined by the detour transport mechanism 60, and is substantially in the middle of the transport path (the first position and the second position) so as to bypass the position (second position) facing the color inkjet head 2b. This is a path that branches from the position (to be described later) and merges downstream of the transport path along the thick arrow (open arrow) shown in FIG. The retransmission path is a path along which the sheet P transported along either the transport path or the detour path is transported along the thick arrow (hatched arrow) shown in FIG.

  The paper feeding unit 10 is configured to feed a plurality of stacked paper sheets P, a paper feeding roller 12 that feeds the paper P from the paper feeding cassette 11, and a control unit 100 to control the paper feeding roller 12 to rotate. A sheet feeding motor (not shown).

  The paper feeding roller 12 feeds the paper P by rotating and contacting the uppermost paper P accommodated in the paper feeding cassette 11. 1 on the left side of the transport mechanism 40 in FIG. 1, the transport guides 15a and 15b extending while curving from the paper feed cassette 11 toward the transport mechanism 40, and both transport guides 15a and 15b upstream of the transport mechanism 40. A feed roller pair 16 disposed between them is provided. The transport guides 15a and 15b and the feed roller pair 16 define a paper transport path that extends from the paper supply unit 10 to the upstream of the transport path. Note that one roller of the feed roller pair 16 is rotated by a feed motor (not shown) controlled by the control unit 100, and the other roller is a driven roller that rotates as the one roller rotates. Further, the feed roller pair 16 also serves as a registration roller that corrects the skew of the paper P when the paper P is fed to the transport mechanism 40.

  In this configuration, the paper feed roller 12 and the feed roller pair 16 are rotated by the control of the control unit 100, whereby the paper P is sent out to the transport guide 15 a, and then the paper P is sandwiched between the feed roller pair 16. The skew is corrected and sent to the transport mechanism 40 through the transport guide 15b.

  As shown in FIGS. 1 and 2, the transport mechanism 40 defines the above-described transport path including a position (first position) facing the inkjet head 2a and a position (second position) facing the inkjet head 2b. At the same time, it is a device that transports the paper P in the transport direction C (the direction of arrow C in FIG. 1) in this transport path. The transport mechanism 40 includes a first unit 41 disposed at a position facing the monochrome inkjet head 2a, a second unit 51 disposed at a position facing the color inkjet head 2b, and the heads 2a and 2b. A plate-shaped conveyance guide 43 disposed between the units 41 and 51 and a conveyance guide 44 disposed in parallel with the conveyance guide 43 and disposed between the units 41 and 51 are provided. The first unit 41 and the second unit 51 are arranged so that the position facing the head 2a and the position facing the head 2b in the transport path are aligned horizontally along the transport direction C. In FIG. 2, the conveyance guide 43 is omitted for easy understanding of the drawing.

  The first unit 41 supports two belt rollers 42, 43, an endless transport belt 45 wound around the rollers 42, 43, and an upper loop of the transport belt 45 from the inner peripheral side. A suction platen 46 that rotates the belt roller 43, and a power source (not shown) that applies a voltage to the suction platen 46. Both the transport motor and the power source are controlled by the control unit 100.

  The suction platen 46 has a pair of comb electrodes (not shown) in which a plurality of long portions that are long along the conveyance direction C are alternately arranged along the main scanning direction. Is a device that adsorbs the paper P onto the conveyor belt 45 by applying the voltage.

  Similar to the first unit 41, the second unit 51 includes two belt rollers 52 and 53, an endless conveyance belt 55 wound around the rollers 52 and 53, and a conveyance belt 55. An adsorption platen 56 that supports the upper loop from the inner periphery side, a conveyance motor (not shown) that rotates the belt roller 53, and a power source (not shown) that applies a voltage to the adsorption platen 56 are provided. These transport motor and power supply are also controlled by the control unit 100. The suction platen 56 has the same configuration as the suction platen 46, and is a device that sucks the paper P onto the transport belt 55 by applying a voltage to a pair of comb electrodes.

  Further, a detour conveyance mechanism 60 is provided around the second unit 51. The detour conveyance mechanism 60 includes a conveyance guide 61, a conveyance roller pair 62 provided in the middle of the conveyance guide 61, a part of the conveyance guide 77 c of the retransmission mechanism 70, conveyance guides 77 a and 77 b, and conveyance roller pairs 74 and 75. And defines the above-mentioned detour route. That is, the detour conveyance mechanism 60 and the retransmission mechanism 70 share some constituent members. In other words, the detour transport mechanism 60 and the retransmission mechanism 70 share a part of the detour path and the retransmission path. Therefore, the structure of these mechanisms is simplified. The conveyance guide 61 extends obliquely downward to the right in FIG. 1 from between the units 41 and 51 on the conveyance path and joins the conveyance guide 77c. One roller of these three transport roller pairs 62, 74, and 75 is rotated by a transport motor (not shown) controlled by the controller 100, and the other roller is a driven roller that rotates as the one roller rotates. It is.

  As shown in FIGS. 1 and 2, a pressing roller 6 is disposed at a position facing the belt roller 42 with the conveyance belt 45 interposed therebetween. The pressing roller 6 presses the sheet P sent out from the sheet feeding unit 10 against the conveying surface on the conveying belt 45. A paper sensor 8 is provided between the pressing roller 6 and the ink jet head 2a. The sheet sensor 8 detects the front end of the sheet P pressed by the pressing roller 6.

  In this configuration, the conveyor belts 45 and 55 are rotated by rotating the belt rollers 43 and 53 clockwise in FIG. 1 under the control of the control unit 100. At this time, the belt rollers 42 and 52 and the pressing roller 6 also rotate as the conveying belts 45 and 55 rotate. At this time, if different potentials are applied to the pair of comb electrodes of the suction platens 46 and 56 under the control of the control unit 100, positive or negative is applied to the portions of the conveyor belts 45 and 55 facing the paper P. Charge is generated, and a charge having a polarity different from that of the previous charge is induced on the surface of the paper P facing the transport belts 45 and 55, and these charges attract each other to attract the paper P to the transport belts 45 and 55. . Thus, the paper P sent out from the paper supply unit 10 is first transported in the transport direction C while being attracted to the transport belt 45. Then, it passes between the transport guides 43 and 44 and is transported in the transport direction C while being attracted to the transport belt 55. Further, at this time, when the sheet P conveyed while being attracted to the conveying belts 45 and 55 passes immediately below the respective ink jet heads 2a and 2b, the control unit 100 controls the ink jet heads 2a and 2b, Ink of each color is ejected toward P. Thus, a desired color image is formed on the paper P.

  On the other hand, when the conveyance roller pair 62, 74, and 75 rotate under the control of the control unit 100, a sorting mechanism 65 (described later) operates to guide the sheet P conveyed by the first unit 41 to the conveyance guide 61. The paper P is transported to the detour path from approximately the middle of the transport path. In this case, since the paper P does not pass through the position facing the color inkjet head 2b, only a desired monochrome image is formed on the paper P.

  As shown in FIG. 1, on the right side of the inkjet head 2b, there are two conveyance guides 71a and 71b that form a part of the retransmission mechanism 70 and extend while curving from the conveyance mechanism 40 toward the paper discharge unit 5. A pair of feed rollers 72 and 73 is provided. These members 71a, 71b, 72, and 73 define a part of the retransmission path and the print path. In addition, one roller of each of the feed roller pairs 72 and 73 is rotated by a feed motor (not shown) controlled by the control unit 100, and the other roller is a driven roller that rotates as the one roller rotates. . A paper sensor 79 is provided in the vicinity of the feed roller pair 72. The sheet sensor 79 detects the trailing edge of the sheet P conveyed from the conveyance mechanism 40.

  In this configuration, when the feed roller pairs 72 and 73 rotate in a predetermined direction under the control of the control unit 100, the paper P transported from the transport mechanism 40 and the detour transport mechanism 60 is fed to the feed roller pairs 72 and 73. 1 is passed through the conveyance guides 71a and 71b while being sandwiched between the sheets, and is sent upward in FIG. At this time, when forming an image on the back surface of the paper P (the back surface of the paper P having a color image formed on the front surface) without discharging the paper P to the paper discharge unit 5, the paper is controlled by the control unit 100. When the rear end of P reaches the vicinity of the feed roller pair 72, each of the feed roller pairs 72 and 73 rotates in the direction opposite to the predetermined direction, thereby transporting the paper P in the reverse direction (downward in FIG. 1).

  As shown in FIG. 1, the re-transmission mechanism 70 includes three pairs of feed rollers 74 to 76 and four pairs of feed rollers in addition to the above-described transport guides 71a and 71b and two pairs of feed rollers 72 and 73. 72, 74 to 76, and conveyance guides 78a to 77c arranged between the feed roller pair 76 and the feed roller pair 16, and a conveyance guide 78 that joins the conveyance guide 15a. One roller of the feed roller pair 76 is also rotated by a feed motor (not shown) controlled by the control unit 100, and the other roller is a driven roller that rotates as one roller rotates. Further, a part of the conveyance guide 77c, the conveyance guides 77a and 77b, and the feed roller pair 74 and 75 also serve as components of the detour conveyance mechanism 60 described above.

  In this configuration, as the feed roller pairs 74 to 76 rotate under the control of the control unit 100, the sheet P conveyed in the reverse direction from the paper discharge unit 5 side is sandwiched between the feed roller pairs 74 to 76. While being conveyed through the conveyance guides 77 a to 77 c and 78, the conveyance rollers are conveyed to the feed roller pair 16. Then, under the control of the control unit 100, the sheet P on which the image is formed on the surface by the rotation of the feed roller pair 16 is transported upstream (paper transport path) in the transport direction C of the transport mechanism 40. The paper P at this time is transported to the transport mechanism 40 in a state where the front and back of the paper P are reversed from when the paper P is sent out from the paper feeding unit 10.

  As shown in FIGS. 1 and 2, a maintenance unit 80 for maintaining the inkjet heads 2 a and 2 b is provided in the printer 1. The maintenance unit 80 suppresses the thickening of the ink in the vicinity of the discharge port 4a of the monochrome inkjet head 2a and the increase in the viscosity of the ink in the vicinity of the discharge port 4a of the color inkjet head 2b. And a second cap mechanism 91. Further, the maintenance unit 80 includes a cleaning member that cleans ink adhering to the conveyor belts 45 and 55 and a wiper mechanism (both not shown) that wipes ink adhering to the ejection surfaces 3a and 3b.

  2 and 3, the first cap mechanism 81 includes an annular first cap 82 disposed around the inkjet head 2a, and a first moving mechanism 83 that moves the first cap 82 in the vertical direction. And have. The first cap 82 surrounds the inkjet head 2a and is in contact with the side peripheral surface of the inkjet head 2a only near the upper end of the inner peripheral surface. Moreover, the lower end part of the 1st cap 82 is formed from elastic members, such as rubber | gum.

  The first moving mechanism 83 includes two flanges 84a and 84b fixed to the side surface of the first cap 82, a guide 85 that slidably supports the flange 84a, a shaft 86 having an external thread formed on the outer peripheral surface, and a control. And a motor 87 that is controlled by the unit 100 and rotates the shaft 86. The guide 85 is fixed to the housing 1a and is passed through a hole formed in the center of the flange 84a. The shaft 86 is screwed into a screw hole formed at the center of the flange 84b and having an internal thread formed on the inner peripheral surface thereof.

  In this configuration, when the shaft 86 rotates forward under the control of the control unit 100, the lower end of the first cap 82 is transported from the retracted position (the position shown in FIG. 3A) where the first cap 82 is separated from the transport belt 45. It moves to the close contact position (position shown in FIG. 3B) in close contact with the belt 45. The retreat position is a position where a sealed space having the discharge surface 3a as a part of the inner wall surface is not formed, and a sealed space surrounded by the discharge surface 3a, the first cap 82 and the conveyor belt 45 is not formed. It is. On the other hand, the close contact position is a position where a sealed space having the discharge surface 3a as a part of the inner wall surface is formed, and a sealed space surrounded by the discharge surface 3a, the first cap 82 and the conveyor belt 45 is formed. is there. At this time, since the upper end of the first cap 82 and the side peripheral surface of the inkjet head 2a are in contact with each other, the space surrounded by the discharge surface 3a, the transport belt 45 and the first cap 82 (external space communicating with the discharge port 4a). ) Is a sealed space. That is, the inkjet head 2 a can be capped with the first cap 82. In this way, it is possible to suppress the thickening of the ink in the vicinity of the ejection opening of the inkjet head 2a. On the other hand, when the shaft 86 rotates reversely under the control of the control unit 100, the first cap 82 moves from the contact position to the retracted position.

  2 and 3, the second cap mechanism 91 includes an annular second cap 92 disposed around the three inkjet heads 2b, and a second movement for moving the second cap 92 in the vertical direction. And a mechanism 93. The second cap 92 surrounds the three inkjet heads 2b, and the upper end of the inner peripheral surface is in contact with the side peripheral surface formed by the three inkjet heads 2b. The lower end portion of the second cap 92 is formed of an elastic member such as rubber. A protruding portion 92a protruding along the sub-scanning direction is formed at the lower left corner of the second cap 92 in FIG.

  The second moving mechanism 93 includes two flanges 94a and 94b fixed to the side surface of the second cap 92, a guide 95 that slidably supports the flange 94a, a shaft 96 having a male screw formed on the outer peripheral surface, and a control. And a motor 97 that is controlled by the unit 100 and rotates the shaft 96. The guide 95 is fixed to the housing 1a and is passed through a hole formed in the center of the flange 94a. The shaft 96 is screwed into a screw hole formed at the center of the flange 94b and having an internal thread formed on the inner peripheral surface thereof.

  In this configuration, when the shaft 96 rotates forward under the control of the control unit 100, the lower end of the second cap 92 is transported from the retracted position (the position shown in FIG. 3A) where the second cap 92 is separated from the transport belt 55. It moves to the close contact position (position shown in FIG. 3B) in close contact with the belt 55. The retreat position is a position where a sealed space having the discharge surface 3b as a part of the inner wall surface is not formed, and a sealed space surrounded by the discharge surface 3b, the second cap 92 and the transport belt 55 is not formed. It is. On the other hand, the close contact position is a position where a sealed space having the discharge surface 3b as a part of the inner wall surface is formed, and a sealed space surrounded by the discharge surface 3b, the second cap 92 and the transport belt 55 is formed. is there. At this time, since the upper end of the second cap 92 is also in contact with the side peripheral surfaces of the three inkjet heads 2b, the space surrounded by the three ejection surfaces 3b, the transport belt 55, and the second cap 92 (the ejection port 4a and The external space that leads to it becomes a sealed space. That is, the inkjet head 2 b can be capped with the second cap 92. In this way, it is possible to suppress the thickening of the ink in the vicinity of the ejection opening of the inkjet head 2b. On the other hand, when the shaft 96 rotates reversely under the control of the control unit 100, the second cap 92 moves from the contact position to the retracted position.

  In addition, between the first unit 41 and the second unit 51 and in the vicinity of the upper end of the conveyance guide 61, the paper P is placed in either the conveyance path or the detour path in conjunction with the operation of the second cap 92. A sorting mechanism 65 for sorting is provided. As shown in FIGS. 2 and 3, the distribution mechanism 65 is fixed to a plate-shaped conveyance guide 66 disposed between the upper end of the conveyance guide 61 and the conveyance guide 44, and both ends of the conveyance guide 66 in the main scanning direction. Two rotating shafts 67 and a lever 68 are provided. The end of each rotation shaft 67 is rotatably supported by the housing 1a.

  As shown in FIG. 2, the lever 68 is fixed on a protruding portion 66 a formed at one end (lower end in the figure) of the transport guide 66 in the main scanning direction. Further, as shown in FIG. 3A, the lever 68 extends obliquely upward to the right from the protruding portion 66a so that the upper end of the lever 68 contacts the protruding portion 92a of the second cap 92 in the retracted position. .

  In this configuration, when the second cap 92 moves from the retracted position to the contact position, the lever 68 swings downward and the transport guide 66 tilts from the horizontal state. In other words, the conveyance guide 66 is inclined so that the position where the paper P faces the color inkjet head 2b is detoured and passed through the detour path from approximately the middle of the transport path. In other words, when the sorting mechanism 65 turns the paper P to the detour path, the second cap 92 is disposed at the close contact position. On the other hand, when the second cap 92 moves from the contact position to the retracted position, the lever 68 swings upward and the conveyance guide 66 becomes horizontal from the tilted state. In this way, the sheet P can pass through the position facing the color inkjet head 2b without passing through the detour path.

  Subsequently, double-sided color printing and double-sided monochrome printing operation of the printer 1 will be described below. The color and monochrome printing operations on one side of the paper P are simply discharged to the paper discharge unit 5 after an image is formed on one side in a double-sided printing operation to be described later. .

  When print data for forming color images on both sides (that is, the front surface and the back surface) of the paper P is transmitted from a PC (personal computer) or the like to the control unit 100, the control unit 100 transfers the conveyance guides 15a and 15b from the paper feed cassette 11. The paper feed unit 10 and the feed roller pair 16 are controlled so that the paper P is fed to the transport mechanism 40 through the paper feed unit 10.

  Next, the control unit 100 controls the transport mechanism 40 so that the paper P is transported in the transport direction C while being attracted to the transport belt 45 and the transport belt 55. At this time, ink is ejected from the inkjet heads 2a and 2b after a predetermined time has elapsed since the control unit 100 detects the front end of the sheet P by the sheet sensor 8 and the sheet P passes through the area facing the inkjet heads 2a and 2b. As described above, the inkjet heads 2a and 2b are controlled. Thus, a color image is formed at a desired position on the surface of the paper P.

  Next, the control unit 100 controls the feed roller pairs 72 and 73 so that the paper P is transported from the transport belt 55 through the transport guides 71a and 71b to the paper discharge unit 5 side. When the trailing edge of the paper P is detected by the paper sensor 79, the control unit 100 controls the feed roller pairs 72 and 73 so as to rotate in the direction opposite to the previous rotation direction.

  Next, the control unit 100 controls the three pairs of feed rollers 74 to 76 so that the paper P is transported to the feed roller pair 16 through the transport guides 77a to 77c and 78. The paper P conveyed to the feed roller pair 16 is in a state where the front and back of the printing surface are turned over, and the paper P is conveyed again to the conveyance mechanism 40 as it is.

  Thereafter, the control unit 100 controls the ink jet heads 2a and 2b in the same manner as when an image is formed on the front surface of the paper P, and a desired color image is formed on the back surface of the paper P. Then, the control unit 100 controls the pair of feed rollers 72 and 73 so that the paper P on which images are formed on both sides is discharged to the paper discharge unit 5. Thus, the double-sided color printing operation on the paper P is completed.

  Also in the case of forming monochrome images on both sides of the paper P, when print data for forming monochrome images on both sides of the paper P is transmitted from the PC or the like to the control unit 100, the control unit 100 sends the conveyance guide 15a from the paper feed cassette 11. , 15b, the paper feed unit 10 and the feed roller pair 16 are controlled so that the paper P is fed to the transport mechanism 40.

  At this time, as shown in FIG. 4, the control unit 100 controls the motor 97 to move the second cap 92 from the retracted position to the contact position. Then, in conjunction with the operation of the second cap 92, the conveyance guide 66 of the distribution mechanism 65 is inclined from the horizontal state, and the position where the sheet P conveyed by the first unit 41 faces the color inkjet head 2b is set. It becomes possible to carry to the detour route so as to detour. Further, since the color ink-jet head 2b that does not contribute to the current printing can be capped with the second cap 92, it is possible to suppress the viscosity increase of the ink in the vicinity of the ejection port 4a of the head 2b. .

  Next, the control unit 100 controls the transport mechanism 40 so that the paper P is transported in the transport direction C while being attracted to the transport belt 45. At this time, the control unit 100 ejects ink from the inkjet head 2a after a predetermined time has elapsed since the front end of the sheet P is detected by the sheet sensor 8 and the sheet P passes through the region facing the inkjet head 2a. The inkjet head 2a is controlled. In this way, a monochrome image is formed at a desired position on the surface of the paper P.

  Next, the control unit 100 controls the feed roller pairs 62 and 72 to 75 so that the paper P on which the monochrome image is formed is conveyed to the paper discharge unit 5 side through the detour path. When the trailing edge of the paper P is detected by the paper sensor 79, the control unit 100 controls the feed roller pairs 72 to 75 so as to rotate in the direction opposite to the previous rotation direction. At this time, the feed roller pair 76 is also controlled so that the paper P is transported to the feed roller pair 16 through the transport guides 77c and 78. The feed roller pair 62 is rotated in the same direction as it is.

  The paper P that has been transported to the feed roller pair 16 is in a state in which the front and back of the printing surface are turned over, and the feed roller pair 16 transports the paper P to the transport mechanism 40 as it is. Thereafter, the control unit 100 controls the inkjet head 2a in the same manner as when an image is formed on the front surface of the paper P, and a desired monochrome image is formed on the back surface of the paper P. Then, the control unit 100 controls the feed roller pairs 62 and 72 to 75 so that the paper P on which images are formed on both sides is discharged to the paper discharge unit 5. After discharging the paper P to the paper discharge unit 5, the control unit 100 controls the motor 97 to move the second cap 92 from the contact position to the retracted position. Then, in conjunction with the operation of the second cap 92, the transport guide 66 of the sorting mechanism 65 becomes horizontal from the tilted state. Thus, the double-sided monochrome printing operation on the paper P is completed.

  When a color image is formed on the front surface of the paper P and a monochrome image is formed on the back surface, the color sensor is formed on the front surface of the paper P as described above, and then the rear edge of the paper P is detected by the paper sensor 79. At this time, the control unit 100 controls the motor 97 to move the second cap 92 from the retracted position to the contact position. The paper P returned to the transport mechanism 40 through the retransmission path forms a monochrome image on the back surface of the paper P as described above, and is then discharged to the paper discharge unit 5 through the detour path.

  Further, when a monochrome image is formed on the front surface of the paper P and a color image is formed on the back surface, a monochrome image is formed on the front surface of the paper P as described above, and then the trailing edge of the paper P is detected by the paper sensor 79. When this is done, the control unit 100 controls the motor 97 to move the second cap 92 from the contact position to the retracted position. Then, the paper P returned to the transport mechanism 40 through the retransmission path forms a color image on the back surface of the paper P as described above, and is then placed in the paper discharge unit 5.

  Next, a maintenance operation for recovering the ejection of the inkjet heads 2a and 2b by the maintenance unit 80 will be described below.

  When a color image is formed on the paper P, the paper passes through a position facing both the heads 2a and 2b, so that foreign matter that has been swollen by the conveyance at this time may adhere to the ejection surfaces 3a and 3b. If foreign matter adheres to the ejection surfaces 3a and 3b, particularly the ejection port 4a, the ink ejection may be disturbed or become unable to be ejected, so that the inkjet heads 2a and 2b need to be recovered. Therefore, after the color image is formed on the paper P, the control unit 100 controls the motors 87 and 97 to move the first and second caps 82 and 92 to the contact positions. Then, after the ink is purged from the inkjet heads 2a and 2b, the control unit 100 controls the motors 87 and 97 to move the first and second caps 82 and 92 to the retracted positions. Thereafter, the control unit 100 controls the wiper mechanism to wipe off ink and foreign matter adhering to the ejection surfaces 3a and 3b. Thus, the maintenance operation for recovering the ejection of both heads 2a and 2b is completed. Ink adhering to the conveyor belts 45 and 55 by purging from both heads 2a and 2b is cleaned by a cleaning member.

  On the other hand, when a monochrome image is formed on the paper P, the paper P passes through the detour path, so that foreign matters such as paper dust are less likely to adhere to the ejection surface 3b of the color inkjet head 2b. Furthermore, since the inkjet head 2b is capped by the second cap 92, foreign matter is more difficult to adhere to the ejection surface 3b. For this reason, it is not necessary to maintain the three inkjet heads 2b after the monochrome printing operation is completed.

  That is, after the monochrome image is formed on the paper P, the control unit 100 controls only the motor 87, moves the first cap 82 to the contact position, and purges ink from the inkjet head 2a. At this time, the second cap 92 is disposed at the close contact position in the previous monochrome printing, and foreign matter does not adhere to the ejection surface 3b, so that ink is not purged from the inkjet head 2b. Thereafter, the control unit 100 controls the motor 87 to move the first cap 82 to the retracted position. Then, the control unit 100 controls the wiper mechanism to wipe away ink and foreign matters attached to the ejection surface 3a. Thus, the maintenance operation for recovering the ejection of the inkjet head 2a is completed. Thereby, when a monochrome image is printed on the paper P, ink consumption by purging of the three inkjet heads 2b is not performed, so that it is possible to more reliably suppress ink consumption.

  As described above, according to the ink jet printer 1 of the present embodiment, when monochrome printing is performed on the paper P (printing only by ink ejection from the ink jet head 2a), the position where the paper P faces the ink jet head 2b in the transport path is determined. The paper P is conveyed through the detour path so as to be detoured. Therefore, it becomes difficult for foreign matter to adhere to the inkjet head 2b. As a result, it is possible to suppress ink consumption due to maintenance (purge) of the inkjet head 2b.

  Further, since the second cap mechanism 91 is provided, it is not necessary to move the inkjet head 2b when capping the inkjet head 2b. For this reason, it is not necessary to secure a space for moving the inkjet head 2b, the apparatus main body can be downsized, and the configuration of the second moving mechanism 93 is simpler than the mechanism for moving the inkjet head 2b. become.

  Further, when the sorting mechanism 65 directs the paper P to the detour path, the cap 92 is disposed at a position where the external space communicating with the discharge port 4a of the inkjet head 2b is a sealed space. For this reason, it is possible to suppress the viscosity of the ink in the vicinity of the ejection port of the inkjet head 2b from increasing. In addition, since the distribution mechanism 65 is provided, the path through which the paper P passes is automatically distributed in conjunction with the operation of the second cap 92. Therefore, it is not necessary to provide a control means for distributing the route.

  Further, a pair of feed rollers 16 that also serve as registration rollers is disposed upstream of the transport mechanism 40, and the first unit 41 and the second unit 51 are disposed so as to be horizontally aligned along the transport direction C (that is, in the transport path). Since the position facing the head 2a and the position facing the head 2b are arranged horizontally), skewing is less likely to occur between these positions on the transport path. Therefore, it is not necessary to provide another registration roller between the first and second units 41 and 51.

  Since the ejection region 4b of each inkjet head 2a, 2b is longer than the paper P in the main scanning direction, it is possible to print on the paper P without moving the inkjet heads 2a, 2b in the main scanning direction. .

  The ink jet printer 1 according to the present embodiment has a device configuration in which the paper discharge unit 5, the four ink jet heads 2 a and 2 b, the transport mechanism 40, the detour transport mechanism 60, and the paper feed unit 10 are arranged in order from the top. In addition, the inkjet printer 1 in this embodiment may be provided horizontally. In this case, the apparatus configuration is such that the paper discharge unit 5, the four inkjet heads 2a and 2b, the transport mechanism 40, the detour transport mechanism 60, and the paper feed unit 10 are arranged along the horizontal direction. That is, the ink jet printer 1 has an apparatus configuration in which the paper discharge unit 5, the four ink jet heads 2 a and 2 b, the transport mechanism 40, the detour transport mechanism 60, and the paper feed unit 10 are arranged along one direction.

[Second Embodiment]
Next, an inkjet printer 201 according to a second embodiment of the present invention will be described below with reference to FIG.

  In the ink jet printer 201 of the present embodiment, the retransmission mechanism 70 is not provided, and the detour conveyance mechanism 260 and the sorting mechanism 265 are disposed between the heads 2a and 2b. Components similar to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. Moreover, although the conveyance guide 71a shown in FIG. 5 differs in part from the shape in 1st Embodiment by not having the resending mechanism 70, since it is substantially the same, it has shown with the same code | symbol.

  The detour conveyance mechanism 260 includes conveyance guides 261 and 262 that are curved upward from the middle of the conveyance path and extend upward, and two pairs of feed rollers 263 and 264. (Path indicated by an arrow). The detour path branches from the transport path between the position facing the inkjet head 2a (first position) and the position facing the inkjet head 2b (second position) and is connected to the paper discharge unit 5. One roller of each pair of feed rollers 263 and 264 is a driven roller that is rotated by a feed motor (not shown) controlled by the control unit 100, and the other roller is rotated as one roller rotates. The feed roller pair 264 is disposed at the center of the paper discharge unit 5 in the sub-scanning direction. Therefore, the paper P discharged by the feed roller pair 264 is discharged to the paper discharge unit 5.

  The sorting mechanism 265 includes a shaft 266, a transport guide 267 that is fixed to the side surface of the shaft 266 and defines a part of the detour path between the transport guide 261, and a motor that rotates the shaft 266 under the control of the control unit 100. (Not shown). In addition, a plate-shaped conveyance guide 244 is provided between the first and second units 41 and 51 instead of the conveyance guide 44 of the first embodiment.

  In this configuration, when a color image is formed on the paper P, the control unit 100 controls the paper feed unit 10, three pairs of feed rollers 16, 72, 73, the transport mechanism 40, and the like, as in the first embodiment. The four inkjet heads 2a and 2b are controlled to form a color image on the paper P sent from the paper supply unit 10 to the transport mechanism 40 along the thick arrow (black arrow) in FIG. The paper is discharged to the paper unit 5. At this time, the conveyance guide 267 of the sorting mechanism 265 is positioned at a closed position where one end is in contact with the conveyance guide 261 and closes the detour path.

  On the other hand, when a monochrome image is formed on the paper P, the control unit 100 controls the sorting mechanism 265 so that one end of the conveyance guide 267 is in a position where the conveyance guide 267 is in contact with the conveyance guide 244 and is opened to the open position where the bypass path is opened. The conveyance guide 267 is swung by rotating the H.266. The control unit 100 controls the paper feed unit 10, the three pairs of feed rollers 16, 263, 264, the first unit 41 of the transport mechanism 40, and the inkjet head 2 a, and the first unit from the paper feed unit 10 A monochrome image is formed on the paper P sent to 41, and the paper P is discharged to the paper discharge unit 5 through a detour path. Also in this embodiment, when a monochrome image is formed on the paper P, the three inkjet heads 2 b may be capped with the second cap 92.

  As described above, also in the inkjet printer 201 according to the present embodiment, when monochrome printing is performed on the paper P, the paper P is transferred to the bypass path so that the paper P is transported by bypassing the position facing the inkjet head 2b in the transport path. It is conveyed through the paper P. Therefore, it becomes difficult for foreign matter to adhere to the inkjet head 2b. As a result, it is possible to suppress ink consumption due to maintenance (purge) of the inkjet head 2b. In the same configuration as that of the first embodiment, the same effect can be obtained.

[Third Embodiment]
Next, an inkjet printer 301 according to a third embodiment of the present invention will be described below with reference to FIG.

  The inkjet printer 301 of the present embodiment is also not provided with the retransmission mechanism 70, and the detour conveyance mechanism 360 and the distribution mechanism 365 are arranged around the first unit 41. Furthermore, the inkjet head 2 a and the first cap mechanism 81 are disposed at a position facing the second unit 51, and the inkjet head 2 b and the second cap mechanism 91 are disposed at a position facing the first unit 41. That is, in the present embodiment, the position facing the inkjet head 2a (first position) and the position facing the inkjet head 2b (second position) are interchanged. In addition, about the thing similar to 1st and 2nd embodiment, it shows with the same sign and abbreviate | omits description.

  The detour conveyance mechanism 360 has three conveyance guides 361 to 363 extending so as to merge from a midway portion of the conveyance guide 15a to substantially the middle of the conveyance path, and two pairs of feed rollers 364a and 364b. A detour route (route indicated by a thick arrow (open arrow) in FIG. 6) is defined. The detour path branches off from the paper transport path formed by the transport guide 15a, and joins the transport path between a position facing the inkjet head 2a (first position) and a position facing the inkjet head 2b (second position). ing. One roller of each pair of feed rollers 364a and 364b is rotated by a feed motor (not shown) controlled by the control unit 100, and the other roller is a driven roller that rotates as the one roller rotates. Similarly to the feed roller pair 16, the feed roller pair 364b also serves as a registration roller for correcting the skew of the paper P.

  The sorting mechanism 365 includes a shaft 366, a curved transport guide 367 that is fixed to a side surface of the shaft 366 and can protrude into the transport guide 15a, and a motor (not shown) that is controlled by the control unit 100 and rotates the shaft 366. have.

  In this configuration, when a color image is formed on the paper P, the control unit 100 includes the paper feeding unit 10, three pairs of feed rollers 16, 72, 73, the transport mechanism 40, and the four inkjet heads 2a, 2b. Then, a color image is formed on the paper P sent from the paper supply unit 10 to the transport mechanism 40 along the thick arrow (black arrow) in FIG. 6, and the paper P is discharged to the paper discharge unit 5. At this time, the transport guide 367 of the sorting mechanism 365 is positioned at a retracted position that does not protrude into the transport guide 15a.

  On the other hand, when a monochrome image is formed on the paper P, the control unit 100 controls the sorting mechanism 365, and the shaft 366 is rotated to the projecting position where the transport guide 367 projects into the transport guide 15a. Rock. The control unit 100 controls the paper feed unit 10, the four pairs of feed rollers 364 a, 364 b, 72, and 73, the second unit 51 of the transport mechanism 40, and the inkjet head 2 a, and bypasses the paper feed unit 10. A monochrome image is formed on the paper P sent to the second unit 51 through the path, and the paper P is discharged to the paper discharge unit 5. Also in this embodiment, when a monochrome image is formed on the paper P, the three inkjet heads 2 b may be capped with the second cap 92.

  As described above, also in the inkjet printer 301 according to the present embodiment, when monochrome printing is performed on the paper P, the paper P is transferred to the bypass path so that the paper P is transported by bypassing the position facing the inkjet head 2b in the transport path. It is conveyed through the paper P. Therefore, it becomes difficult for foreign matter to adhere to the inkjet head 2b. As a result, it is possible to suppress ink consumption due to maintenance (purge) of the inkjet head 2b. In the same configuration as in the first and second embodiments, the same effect can be obtained.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. For example, the maintenance unit 80 in the first to third embodiments described above may not be provided. In this case, a controlled motor is provided in the control unit 100 capable of rotating the rotation shaft 67 of the sorting mechanism 65, and the control unit 100 directly controls the sorting mechanism 65 to transport the paper P to the bypass path or the transport path. May be. Even in this case, the same effect as in the first embodiment described above can be obtained. In addition, it is not necessary to provide the protrusion 92a and the lever 68. Further, the position facing the inkjet head 2a (first position) and the position facing the inkjet head 2b (second position) may not be aligned in the horizontal direction. Further, the paper feed unit (paper feed unit) and the paper discharge unit may be arranged at a position sandwiching the conveyance mechanism 40 in the horizontal direction, or only one of them is arranged in parallel with the conveyance mechanism 40. May be. Further, a retransmission path may be formed below the paper feeding unit 10. Further, a registration roller different from the feed roller pair 16 may be provided upstream of the transport mechanism 40.

1 Inkjet printer (inkjet recording device)
2a Inkjet head (first recording head)
2b Inkjet head (second recording head)
4a Discharge port 4b Discharge area 16 Feed roller pair (registration roller)
40 transport mechanism 41 first unit 45 transport belt 51 second unit 60, 260, 360 detour transport mechanism 65, 265, 365 distribution mechanism (distribution means)
70 Retransmission mechanism (reverse transport mechanism)
91 Second cap mechanism (cap mechanism)
92 Second cap (cap)
93 Second moving mechanism (moving mechanism)

The inkjet recording apparatus of the present invention includes first and second recording heads each having an ejection port for ejecting ink, a first position facing the ejection port of the first recording head, and the ejection of the second recording head. A transport mechanism that defines a transport path of the recording medium including a second position facing the exit, and the first position and the second position so that the recording medium is transported around the second position. A position where a detour conveyance mechanism that defines a detour path that leads to the conveyance path , a cap, and a sealed space in which a surface on which the discharge port of the second recording head is formed is a part of an inner wall surface is formed And a cap mechanism having a moving mechanism for moving the cap between the position where the sealed space is not formed, and a sorter that distributes the recording medium to either the transport path or the detour path It is equipped with a door. When the sorting unit is in a state of directing the recording medium to the detour path, the cap is preferably disposed at a position where the sealed space is formed.

According to this, when printing is performed on the recording medium only by ink ejection from the first recording head, the recording medium can be transported through the recording medium to the detour path so that the recording medium is transported while bypassing the second position. Become. This makes it difficult for foreign matter (dust such as paper dust) to adhere to the second recording head. As a result, ink consumption due to maintenance of the second recording head can be suppressed. In addition, when the recording medium is turned to the detour path, the external space leading to the ejection port of the second recording head can be a sealed space. For this reason, it is possible to suppress the viscosity of the ink in the vicinity of the ejection opening of the second recording head from increasing.

Claims (13)

First and second recording heads each having an ejection port for ejecting ink;
A transport mechanism that defines a transport path of a recording medium including a first position facing the ejection port of the first recording head and a second position facing the ejection port of the second recording head;
A detour conveyance mechanism that defines a detour path connected to the transport path between the first position and the second position so that the recording medium is detoured and conveyed by the second position. An ink jet recording apparatus. The transport mechanism includes a transport belt that faces the second recording head and transports a recording medium to the second position;
An annular cap disposed around the second recording head so as to surround the second recording head, and the cap between a position where the cap is in close contact with the conveying belt and a position where the cap is separated from the conveying belt The inkjet recording apparatus according to claim 1, further comprising a cap mechanism having a moving mechanism for moving the ink. The cap and the cap are moved between a position where a sealed space having a part of the inner wall surface of which the ejection port of the second recording head is formed is formed and a position where the sealed space is not formed. A cap mechanism having a moving mechanism;
A distribution unit that distributes the recording medium to either the transport path or the detour path;
The inkjet recording apparatus according to claim 1, wherein the cap is disposed at a position where the sealed space is formed when the distribution unit directs the recording medium to the detour path. The transport path is defined by the transport mechanism so that the first and second positions are aligned horizontally along the transport direction of the recording medium,
The inkjet recording apparatus according to claim 1, wherein a registration roller that corrects skew of the recording medium is provided upstream of the transport mechanism. A reverse conveyance mechanism that reverses the recording medium conveyed by the conveyance mechanism and defines a retransmission path to be retransmitted to the conveyance mechanism;
The inkjet recording apparatus according to claim 1, wherein the reverse conveyance mechanism and the detour conveyance mechanism share a part of a mutual path. The first recording head ejects black ink;
The inkjet recording apparatus according to claim 1, wherein the second recording head discharges color ink other than black ink. Each of the first and second recording heads has a discharge region in which a plurality of the discharge ports are formed,
The inkjet recording according to any one of claims 1 to 6, wherein the ejection region has a length equal to or greater than a length of the recording medium in a direction orthogonal to a conveyance direction of the recording medium. apparatus.   The inkjet recording apparatus according to claim 1, wherein the first and second recording heads, the transport mechanism, and the detour transport mechanism are arranged in one direction. A paper feeding unit capable of accommodating one or more recording media and supplying the recording media to the transport mechanism;
A paper discharge unit that accommodates the recording medium conveyed from the conveyance mechanism;
9. The paper discharge unit, the first and second recording heads, the transport mechanism, the bypass transport mechanism, and the paper feed unit are disposed in the one direction. Inkjet recording device. The first recording head ejects black ink;
The second recording head ejects color ink other than black ink,
A maintenance unit for performing maintenance for recovering ejection of the first and second recording heads;
A control unit for controlling the maintenance unit;
The control unit controls the maintenance unit to perform maintenance of the first and second recording heads after printing a color image on a recording medium, and only prints the first recording head after printing a monochrome image on the recording medium. The inkjet recording apparatus according to claim 1, wherein the maintenance unit is controlled to perform maintenance. The transport path is defined by the transport mechanism so that the first and second positions are sequentially arranged along the transport direction of the recording medium;
2. The inkjet recording according to claim 1, wherein the bypass path is branched from the transport path between the first and second positions and merges with the transport path at a position downstream of the second position. apparatus. A paper discharge unit for storing the recording medium transported from the transport mechanism;
The transport path is defined by the transport mechanism so that the first and second positions are sequentially arranged along the transport direction of the recording medium;
The inkjet recording apparatus according to claim 1, wherein the bypass path is branched from the transport path between the first and second positions and connected to the paper discharge unit. One or more recording media can be accommodated, and further includes a paper feeding unit that supplies the recording media to the transport mechanism;
The transport path is defined by the transport mechanism so that the second and first positions are arranged in order along the transport direction of the recording medium;
2. The detour path according to claim 1, wherein the detour path is branched from a path connected to the upstream of the transport path from the paper feeding unit and joins the transport path between the first and second positions. Inkjet recording device.

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