JP6255803B2 - Liquid ejection device - Google Patents

Description

  The present invention relates to a liquid ejection apparatus that ejects a liquid such as ink.

  In a liquid ejecting apparatus, a technique is known in which images are recorded on both a first surface of a recording medium and a second surface opposite to the first surface. In addition, from the viewpoint of preventing contamination due to liquid adhering to a recording medium in a liquid ejection apparatus, a technique is known in which heat is applied to a recording medium after image recording by a roller to dry the recording medium. For example, in Patent Document 1, the paper 3 is conveyed while being sandwiched between the roller 46 and the roller 72 including the heater 73, and heat is applied to the paper 3 on which an image is recorded on the first surface to thereby remove the paper 3. dry. Then, after the rollers 46 and 72 hold the rear end of the sheet 3, the rotation of the rollers 46 and 72 is temporarily stopped, and then the rotation direction of the rollers 46 and 72 is reversed to perform refeeding. An image is recorded on the second side.

JP 2001-063019 (see paragraphs 0040 and 0041 and FIG. 10)

  Generally, a roller that applies heat to a recording medium is configured to contact the other roller with a relatively large pressure in order to increase the contact area with the recording medium from the viewpoint of improving the drying efficiency. Therefore, when the rotation direction of the rollers 46 and 72 is reversed as in Patent Document 1, a load applied to a mechanism (belt, gear, etc.) for rotating the roller is increased, and the mechanism is easily fatigued.

  An object of the present invention is to provide a liquid that records an image on both sides of a recording medium and can reduce the load on a mechanism that rotates the roller in a configuration in which the recording medium after image recording is dried by the heat of the roller. It is to provide a discharge device.

To achieve the above object, according to the present onset bright, it has a plurality of discharge ports for discharging liquid, a liquid discharge head, the recording medium toward the recording position facing the plurality of discharge ports first A first transport unit configured to transport in the direction, and a recording medium disposed downstream of the recording position in the first direction and transported by the first transport unit in the first direction and the first direction. A second conveying unit configured to convey in a second direction opposite to the one direction, a first roller configured to rotate in one direction, the downstream side in the first direction from the recording position, and A second roller that contacts the first roller at a first contact point on the upstream side in the first direction with respect to the second transport unit ; and a downstream side in the second direction with respect to the second transport unit and the recording position. before the second contact also in the second direction upstream side Including a third roller in contact with the first roller, and the recording medium transported by the first transport unit is directed to the transport path of the second transport unit by the first roller and the second roller in the first direction. And the second roller by the first roller and the third roller to re-feed the recording medium conveyed in the second direction by the second conveyance unit to the conveyance path of the first conveyance unit. configured to convey the direction, and a third conveying section, wherein configured to first heat the low la, heater and the liquid discharge head, the first conveyor, the second conveying unit, A control unit configured to control the third transport unit and the heater, and the control unit records the image on the first surface of the recording medium so as to record the image. A first step of controlling one transport unit; After the first step, the second step of controlling the second transport unit so as to transport a recording medium having an image recorded on the first surface in the first direction and the second direction; After the second step, the third transport unit is controlled so that the recording medium transported in the second direction is transported toward the recording position. After the third step, the recording is performed after the third step. Performing the fourth step of controlling the liquid ejection head and the first transport unit so as to record an image on the second surface opposite to the first surface of the medium, and in the second step When the recording medium on which the image is recorded on the first surface is transported in the first direction and passes through the first contact, the heated first roller contacts the second surface, The heat of the first roller is applied to the second surface, and then the front When the recording medium having an image recorded on the first surface is conveyed in the second direction and passes through the second contact, the heated first roller contacts the first surface, and A liquid ejecting apparatus is provided , wherein the heater is controlled so that heat of the first roller is applied to a first surface .
According to the present invention, when images are recorded on both sides of a recording medium, heat is applied to the recording medium while the recording medium is conveyed by the first roller and the second roller that rotate in one direction, and then, Heat can be applied to the recording medium while the recording medium is conveyed by the first roller and the third roller that rotate in the direction. That is, according to the present invention, it is not necessary to reverse the rotation direction of the heated roller in the configuration in which the image is recorded on both sides of the recording medium and the recording medium after image recording is dried by the heat of the roller. The load applied to the mechanism for rotating the roller can be reduced.
Moreover, according to the present invention, the drying efficiency of the recording medium can be improved by heating the first roller that contacts the recording surface with the heater.
Since the first roller contacts both the second roller and the third roller, the heat of the first roller is quickly transmitted to the second roller and the third roller by heating the first roller with a heater. .

According to the reference example of the present invention, the liquid ejection head having a plurality of ejection openings for ejecting liquid and the recording medium are conveyed in the first direction toward the recording position facing the plurality of ejection openings. A configured first transport unit and a recording medium that is disposed downstream of the recording position in the first direction and transported by the first transport unit in the first direction, and the recording medium A second transport section configured to transport the recording medium in a second direction opposite to the first direction and pass the recording position; a first roller configured to rotate in one direction; A recording medium that includes a second roller in contact with one roller and a third roller in contact with the first roller, and that has been transported in the second direction by the second transport unit and has passed through the recording position; Conveyed by the roller and the second roller, The recording medium conveyed by the first roller and the second roller is configured to be conveyed by the first roller and the third roller in order to send the recording medium again to the conveying path of the first conveying unit. A liquid ejection device comprising: a third transport unit; and a heating unit configured to heat at least one of the first roller, the second roller, and the third roller. An apparatus is provided.

According to the above reference example , as in the present invention, when an image is recorded on both sides of the recording medium, heat is applied to the recording medium while the recording medium is conveyed by the first roller and the second roller that rotate in one direction. Then, further, heat can be applied to the recording medium while the recording medium is conveyed by the first roller and the third roller that rotate in one direction. That is, according to the first and second aspects, in the configuration in which an image is recorded on both surfaces of the recording medium and the recording medium after image recording is dried by the heat of the roller, the rotation direction of the heated roller is reversed. Since it is not necessary, the load applied to the mechanism for rotating the roller can be reduced.

  At least the first roller may be a driving roller. Since the first roller contacts both the second roller and the third roller, the rotation of the first roller is easily transmitted to both the second roller and the third roller. Therefore, as described above, if at least the first roller is a driving roller, the second roller and the third roller rotate in accordance with the rotation of the first roller even if the second roller and the third roller are driven rollers. Slip is unlikely to occur between the recording medium and each of the first roller, the second roller, and the third roller. Thereby, the disturbance of the image resulting from slip can be suppressed.

  The first roller and the second roller may be driving rollers. A roller that comes into contact with the recording surface of the recording medium (the surface on which an image has been recorded; that is, the surface to which the liquid ejected from the ejection port adheres) contacts the recording surface through the liquid that has adhered to the recording surface. When a slip occurs between the roller and the recording surface, the liquid spreads on the recording surface and the image is likely to be disturbed. The first roller and the second roller are in contact with the recording surface. The third roller does not contact the recording surface. According to the above configuration, since the second roller is a driving roller in addition to the first roller, not only the slip between the first roller and the recording surface but also the second roller and the recording surface Slip can also be suppressed and image disturbance can be more reliably suppressed.

  A one-way clutch may be provided on the second roller. In this case, when the second roller slips with respect to the recording medium, the transmission of the driving force to the second roller is released by the action of the one-way clutch, and the second roller rotates in accordance with the conveyance of the recording medium (recording). It rotates at a speed corresponding to the conveyance speed of the medium (that is, it rotates with the recording medium). As a result, slippage between the second roller and the recording surface can be more reliably suppressed, and image distortion can be more reliably suppressed.

  The third roller may be a driven roller. Since the third roller does not contact the recording surface, there is no need to use the third roller as a driving roller from the viewpoint of suppressing image disturbance. Therefore, in this case, the configuration can be simplified.

  At least the outer peripheral surface of the first roller may have higher water repellency than the outer peripheral surface of the third roller. When the water repellency of the outer peripheral surface of the roller in contact with the recording surface is low, the liquid adhering to the recording surface easily moves to the outer peripheral surface of the roller, which may cause stains on the recording medium. The first roller contacts the recording surface. The third roller does not contact the recording surface. According to the above configuration, at least the outer peripheral surface of the first roller has higher water repellency than the outer peripheral surface of the third roller, so that the liquid adhering to the recording surface is difficult to move to the outer peripheral surface of the first roller. Dirt can be suppressed.

  The outer peripheral surfaces of the first roller and the second roller may have higher water repellency than the outer peripheral surface of the third roller. The first roller and the second roller are in contact with the recording surface. According to the above configuration, since the outer peripheral surface of the second roller in addition to the first roller has higher water repellency than the outer peripheral surface of the third roller, the liquid adhering to the recording surface is applied to the outer peripheral surface of the first roller. Not only the movement but also the movement of the second roller to the outer peripheral surface can be suppressed, and the contamination of the recording medium can be more reliably suppressed.

  The second roller may be configured to have a smaller contact area with the recording medium than the third roller. The second roller contacts the recording surface. The third roller does not contact the recording surface. According to the above configuration, it is possible to suppress the liquid adhering to the recording surface from moving to the second roller.

  The second roller may include a plurality of rotating bodies arranged at intervals with respect to the first direction and an orthogonal direction orthogonal to the second direction. In this case, the contact area with the recording medium can be reduced with a relatively simple configuration.

  According to the present invention, in the configuration in which an image is recorded on both sides of the recording medium and the recording medium after image recording is dried by the heat of the roller, it is not necessary to reverse the rotation direction of the heated roller. The load applied to the rotating mechanism can be reduced.

It is a schematic side view which shows the inside of the inkjet printer which concerns on one Embodiment of this invention. It is a top view which shows the inkjet head contained in the printer of FIG. FIG. 3 is a partial enlarged view showing a region III surrounded by a one-dot chain line in FIG. 2. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 2 is a block diagram illustrating an electrical configuration of the printer of FIG. 1. It is a flowchart which shows the control content which the controller of a printer performs. It is a flowchart which shows the content of the double-sided recording control of FIG. (A) is the elements on larger scale for demonstrating the conveyance aspect by a 1st roller, a 2nd roller, and a 3rd roller. (B) is a side view of a 1st roller, a 2nd roller, and a 3rd roller. It is a schematic side view which shows the inside of the inkjet printer which concerns on the reference example of this invention. It is the elements on larger scale for demonstrating the conveyance aspect by the 1st roller, the 2nd roller, and the 3rd roller in the reference example of this invention.

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

First, an overall configuration of an inkjet printer 1 according to an embodiment of the present invention will be described with reference to FIG.

  The printer 1 includes a rectangular parallelepiped casing 1a. A paper discharge unit 31 is provided on the top of the casing 1a. An ink jet head 10, a platen 7, a transport unit 20, a sensor 32, a paper feed unit 1c, a controller 1p, and the like are accommodated in the internal space of the housing 1a. In the internal space of the housing 1a, a transport path for transporting the paper P is formed from the paper feed unit 1c toward the paper discharge unit 31 along the thick arrow shown in FIG. The housing 1a is detachably provided with a cartridge (not shown) that stores black ink supplied to the head 10. The cartridge is connected to the head 10 via a tube or the like and supplies ink to the head 10.

  The head 10 is a line head that is long in the main scanning direction (direction perpendicular to the paper surface of FIG. 1). The lower surface of the head 10 is a discharge surface 10x in which a plurality of discharge ports 14a are opened (see FIGS. 3 and 4).

  The platen 7 is made of a flat plate and is disposed at a position facing the discharge surface 10x. A predetermined gap suitable for recording is formed between the surface 7x of the platen 7 and the ejection surface 10x.

  The transport unit 20 includes a first transport unit 20a, a second transport unit 20b, and a third transport unit 20c. The first transport unit 20a is configured to transport the paper P sent out from the paper feed unit 1c toward the recording position X in a first direction (direction indicated by a black arrow in FIG. 1) D1, and a roller It includes pairs 22, 23 and guides 29a, 29b. The recording position X is a position facing the plurality of ejection openings 14 a on the surface 7 x of the platen 7. The second transport unit 20b is disposed downstream of the recording position X in the first direction D1, and the sheet P transported by the first transport unit 20a is in the second direction opposite to the first direction D1 and the first direction D1. (The direction indicated by the white arrow in FIG. 1) It is configured to be conveyed to D2, and includes a pair of rollers 26 and 27 and a guide 29e. The roller pairs 26 and 27 are forward / reverse roller pairs capable of forward / reverse rotation. The third transport unit 20c transports the paper P transported by the first transport unit 20a in the first direction D1 toward the transport path of the second transport unit 20b by the first roller 25a and the second roller 25b, and The paper P transported in the second direction D2 by the second transport unit 20b is transported in the second direction D2 by the first roller 25a and the third roller 25c in order to send it again into the transport path of the first transport unit 20a. It is configured. The third transport unit 20c includes a roller group 25 including three rollers 25a to 25c, roller pairs 24 and 28, guides 29c, 29d, 29f, 29g, and 29h, and a cassette 21. Here, the first direction D1 is a direction in which the paper P is conveyed from the paper feed tray 1c1 through the recording position X to the paper discharge unit 31. The second direction D2 is a direction in which the paper P is transported after passing through the recording position X until it is sent again to the transport path of the first transport unit 20a (upstream in the first direction D1 from the recording position X). .

  The roller pairs 22 to 24 and 26 to 28 are arranged at appropriate intervals in the transport path of the paper P. One roller of each of the roller pairs 22 to 24 and 26 to 28 is a driving roller that is rotated by driving of the transport motor 20M (see FIG. 5) under the control of the controller 1p. The other roller of each of the roller pairs 22 to 24 and 26 to 28 is a driven roller that rotates as the one roller rotates. In each of the roller pairs 22 to 24 and 26 to 28, one roller and the other roller rotate in opposite directions while sandwiching the paper P. Thereby, the paper P is conveyed. All the roller pairs 22 to 24 and 26 to 28 are composed of rollers having the same diameter, and rotate at the same speed according to the driving of the transport motor 20M. Each guide 29a-29h includes a pair of plates. The pair of plates are separated from each other in a direction orthogonal to the plane of the plates, and define a space through which the paper P can pass. The cassette 21 is disposed above the paper feed tray 1c1 and below the platen 7, and defines a space through which the paper P can pass.

  Among the three rollers 25a to 25c constituting the roller group 25, the second roller 25b and the third roller 25c have substantially the same diameter as the rollers constituting the roller pairs 22 to 24 and 26 to 28. 25a has a slightly larger diameter than these rollers.

  The 2nd roller 25b and the 3rd roller 25c are arranged in the position which contacts the 1st roller 25a, respectively. The first contact C1, which is a contact point between the first roller 25a and the second roller 25b, is disposed downstream of the recording position X and upstream of the second transport unit 20b with respect to the first direction D1. The second contact point C2, which is the contact point between the first roller 25a and the third roller 25c, is disposed downstream of the second transport unit 20b and upstream of the recording position X in the second direction D2.

  As shown in FIG. 8A, the first roller 25a and the second roller 25b rotate in opposite directions while holding the paper P at the first contact C1. The first roller 25a and the third roller 25c rotate in opposite directions while sandwiching the paper P at the second contact C2. Thereby, the paper P is conveyed. Each of the three rollers 25a to 25c is configured to rotate in one direction.

  The first roller 25a and the second roller 25b are driving rollers that are rotated by driving of the transport motor 25M (see FIG. 5) under the control of the controller 1p. The third roller 25c is a driven roller that rotates as the first roller 25a rotates.

  A one-way clutch 25bC is provided on the second roller 25b (see FIG. 5). That is, the second roller 25b is connected to the transport motor 25M via the one-way clutch 25bC. The second roller 25b tends to slip with respect to the paper P because the conveyance speed by the first roller 25a is larger than the conveyance speed by the second roller 25b. At this time, the transmission of the driving force from the transport motor 25M to the second roller 25b is released by the action of the one-way clutch 25bC, and the second roller 25b rotates in accordance with the transport of the paper P (at the transport speed of the paper P). Rotate at the corresponding speed (ie, follow the paper P).

  The first roller 25a is heated by a heater 25ah (see FIG. 5). When the heater 25ah is turned on under the control of the controller 1p, the first roller 25a is heated, and the heat of the first roller 25a is transmitted to the second roller 25b and the third roller 25c. As a result, heat is applied to the portions of the paper P disposed at the contact points C1 and C2, and the portions are dried.

  As shown in FIG. 8B, the second roller 25b includes four rotating bodies 25b1 arranged at intervals with respect to the main scanning direction (the orthogonal direction orthogonal to the first direction D1 and the second direction D2). Including. These rotators 25b1 are fixed to a shaft 25bx extending in the main scanning direction, and rotate as the shaft 25bx rotates. Each of the first roller 25a and the third roller 25c is composed of one rotating body that is long in the main scanning direction, and is fixed to the shafts 25ax and 25cx extending in the main scanning direction, and accompanying the rotation of the shafts 25ax and 25cx. Rotate. Thus, the second roller 25b is configured to have a smaller contact area with the paper P than the third roller 25c.

  The outer peripheral surfaces of the first roller 25a and the second roller 25b have higher water repellency than the outer peripheral surface of the third roller 25c. For example, the material of the first roller 25a and the second roller 25b may be a material having higher water repellency than the material of the third roller 25c. Alternatively, the outer peripheral surfaces of the first roller 25a and the second roller 25b may be water-repellent.

  The guide 29d is branched to define two paths: a first path connecting the roller pair 26 and the first contact C1, and a second path connecting the roller pair 26 and the second contact C2. A selection plate 25x is provided at the branch point in the guide 29d (see FIG. 8A). The selection plate 25x rotates around the shaft 25x1 under the control of the controller 1p. As a result, either the first route or the second route is selected.

  The sensor 32 outputs a signal based on the presence / absence of the paper P, and is arranged upstream of the roller pair 26 in the first direction D1 and downstream of the roller group 25 in the first direction D1.

  The paper feed unit 1c includes a paper feed tray 1c1 and a paper feed roller 1c2. The paper feed tray 1c1 is detachable from the housing 1a. The paper feed tray 1c1 is a box whose upper surface is open and can accommodate a plurality of papers P. The paper feed roller 1c2 is rotated by the drive of a paper feed motor 1cM (see FIG. 5) under the control of the controller 1p, and feeds the uppermost paper P in the paper feed tray 1c1.

  The controller 1p includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory: including a nonvolatile RAM), an ASIC (Application Specific Integrated Circuit), and an I / F (Interface). , I / O (Input / Output Port), timer, etc. The ROM stores programs executed by the CPU, various fixed data, and the like. The RAM temporarily stores data (such as image data) necessary for executing the program. The ASIC performs rewriting and rearrangement of image data (for example, signal processing and image processing). The I / F performs data transmission / reception with an external device (for example, a PC connected to the printer 1). I / O inputs / outputs detection signals of various sensors. Note that the controller 1p does not include an ASIC, and image data may be rewritten and rearranged by a program executed by the CPU.

  Next, a more detailed configuration of the head 10 will be described with reference to FIGS. In FIG. 3, the pressure chamber 16 and the aperture 15 which are located below the actuator unit 17 and should be indicated by dotted lines are indicated by solid lines.

  The head 10 includes a flow path unit 12, a reservoir unit, eight actuator units 17, eight FPCs (flat flexible substrates) 19, a circuit board, and the like.

  The channel unit 12 is a laminated body in which nine rectangular metal plates 12a, 12b, 12c, 12d, 12e, 12f, 12g, 12h, and 12i having substantially the same size are stacked, and a channel is formed therein. ing. The flow path includes a manifold flow path 13, a sub-manifold flow path 13 a, and an individual flow path 14. An opening 12 y is formed on the upper surface 12 x of the flow path unit 12. The manifold channel 13 is a channel having an opening 12y at one end. The sub manifold channel 13 a is a channel branched from the manifold channel 13. The individual flow path 14 is provided for each discharge port 14a, and reaches from the outlet of the sub-manifold flow path 13a to the discharge port 14a via the aperture 15 and the pressure chamber 16 that are flow-path resistance restrictors. It is a flow path. The lower surface of the flow path unit 12 opposite to the upper surface 12x is the discharge surface 10x.

  The pressure chamber 16 is provided for each discharge port 14a. That is, one pressure chamber 16 is connected to one discharge port 14a. The openings of the pressure chambers 16 have a substantially rhombus shape and are arranged in a matrix in the fixed region of each actuator unit 17 on the upper surface 12x (see FIG. 3). In the area facing the fixed area of each actuator unit 17 on the lower surface (discharge surface 10x) of the flow path unit 12, the discharge ports 14a are arranged in a matrix with the same arrangement pattern as the pressure chambers 16.

  A flow path including a reservoir is formed inside the reservoir unit. The reservoir temporarily stores the ink supplied from the cartridge. One end of the flow path is connected to the cartridge via a tube or the like, and the other end is connected to the flow path of the flow path unit 12. Irregularities are provided on the lower surface of the reservoir unit. The convex portion is fixed to a region on the upper surface 12x that does not overlap with the actuator unit 17 (a region surrounded by a two-dot chain line including the opening 12y shown in FIG. 2). The end of the flow path is open at the tip end surface of the convex portion (the surface fixed to the upper surface 12x). The recess faces the upper surface 12x, the surface of the actuator unit 17, and the surface of the FPC 19 with a slight gap therebetween.

  As shown in FIG. 2, the eight actuator units 17 are arranged in a zigzag pattern in two rows along the main scanning direction, and are fixed to the upper surface 12x. Each actuator unit 17 has a trapezoidal outer shape and covers openings of a plurality of pressure chambers 16 formed in a fixed region of the actuator unit 17. Each actuator unit 17 includes a piezoelectric layer, a common electrode, and an individual electrode. Among the members described above, the piezoelectric layer and the common electrode have a trapezoidal shape having a size that defines the outer shape of the actuator unit 17. The individual electrode is provided for each pressure chamber 16 and is disposed at a position overlapping with each pressure chamber 16 in the vertical direction on the upper surface of the piezoelectric layer. A portion corresponding to each individual electrode of the actuator unit 17 functions as one piezoelectric actuator. Each actuator can be deformed independently by application of a voltage via the FPC 19 and changes the volume of the corresponding pressure chamber 16 to apply energy to the ink in the pressure chamber 16. Thereby, ink is discharged from the discharge port 14a.

  The eight FPCs 19 are connected to each of the eight actuator units 17. Each FPC 19 has one end fixed to the actuator unit 17 and the other end fixed to the circuit board. Each FPC 19 has wiring and terminals corresponding to each electrode of the actuator unit 17, and a driver IC is mounted in the middle thereof. Each wiring is connected to the output terminal of the driver IC. The circuit board adjusts the signal input from the controller 1p, and outputs the adjusted signal to the driver IC via the wiring of the FPC 19. The driver IC converts a signal input from the circuit board into a drive signal, and transmits the drive signal to each electrode of the actuator unit 17 through the wiring of the FPC 19.

  Next, the control content executed by the controller 1p will be described with reference to FIGS.

  First, as shown in FIG. 6, the controller 1p determines whether or not a recording command has been received from an external device (S1). When the recording command is not received (S1: NO), the controller 1p repeats the process of S1. When the recording command is received (S1: YES), the controller 1p turns on the heater 25ah (S2).

  After S2, the controller 1p refers to the recording command and determines whether or not single-sided recording is performed (S3). The recording command includes a single-sided recording or a double-sided recording command. Single-sided recording refers to recording an image on the surface of the paper P (the surface facing downward in the paper feed tray 1c1). Double-sided recording refers to recording an image on both the front surface and the back surface of the paper P (the surface facing upward in the paper feed tray 1c1). The front surface is an example of the first surface of the present invention, and the back surface is an example of the second surface of the present invention.

  In the case of single-sided recording (S3: YES), the controller 1p controls the paper feed motor 1cM, the conveyance motors 20M and 25M, the head 10, and the selection plate 25x to execute control related to single-sided recording (S4).

  In S4, the controller 1p first sends the uppermost paper P in the paper feed tray 1c1 from the paper feed unit 1c, and transports it in the first direction D1 by the first transport unit 20a. The controller 1p ejects ink from the ejection port 14a toward the surface of the paper P when the paper P passes through the recording position X. As a result, an image is recorded on the surface of the paper P. Thereafter, the controller 1p conveys the paper P in the first direction D1 by the first roller 25a and the second roller 25b, and moves the paper P toward the conveyance path of the second conveyance unit 20b, and further by the second conveyance unit 20b. The sheet is conveyed in the first direction D1 and discharged from the opening 30 formed in the upper part of the housing 1a to the sheet discharge unit 31.

  The controller 1p maintains the selection plate 25x in the state indicated by the solid line in FIG. 8A during S4.

  In the case of double-sided recording (S3: NO), the controller 1p controls the paper feed motor 1cM, the transport motors 20M and 25M, the head 10, and the selection plate 25x to execute control relating to double-sided recording (S5).

  In S5, the controller 1p first executes control related to recording on the surface of the paper P as shown in FIG. 7 (S11).

  In S11, the controller 1p first sends the uppermost paper P in the paper feed tray 1c1 from the paper feed unit 1c, and transports it in the first direction D1 by the first transport unit 20a. The controller 1p ejects ink from the ejection port 14a toward the surface of the paper P when the paper P passes through the recording position X. As a result, an image is recorded on the surface of the paper P. Thereafter, the controller 1p conveys the paper P in the first direction D1 by the first roller 25a and the second roller 25b, and moves the paper P toward the conveyance path of the second conveyance unit 20b, and further by the second conveyance unit 20b. It is conveyed in the first direction D1.

  After S11, the controller 1p determines whether or not the trailing edge of the paper P has reached the detection position of the paper P by the sensor 32 based on the signal from the sensor 32 (S12). The controller 1p determines that the trailing edge of the paper P has reached the detection position when the signal from the sensor 32 is switched from a signal indicating the presence of the paper P to a signal indicating the absence of the paper P. When the trailing edge of the paper P has not reached the detection position (S12: NO), the controller 1p repeats the process of S12.

  When the trailing edge of the paper P reaches the detection position (S12: YES), the controller 1p outputs a drive stop command to the transport motor 20M (S13). At this time, the paper P is sandwiched between the roller pairs 26 and 27, and the rear end of the paper P is in the detection position.

  After S13, the controller 1p outputs a reverse rotation drive command to the transport motor 20M (S14). As a result, the roller pairs 26 and 27 rotate in the reverse direction, and the paper P is conveyed in the second direction D2.

  During S5, the controller 1p does not output a reverse rotation drive command to the transport motor 25M, and continues to rotate the rollers 25a to 25c of the roller group 25 in a certain direction.

  After S14, the controller 1p executes control related to recording on the back surface of the paper P (S15).

  In S15, the controller 1p first transports the paper P transported in the second direction D2 by the second transport unit 20b in the second direction D2 by the first roller 25a and the third roller 25c, and the first transport unit. It is fed again into the transport path 20a (on the upstream side in the first direction D1 from the recording position X and immediately upstream in the first direction D1 of the roller pair 22). Then, the controller 1p transports the paper P again in the first direction D1 by the first transport unit 20a, and ejects ink from the ejection port 14a toward the back surface of the paper P when the paper P passes the recording position X. Let Thereby, an image is recorded on the back surface of the paper P. Thereafter, the controller 1p conveys the paper P in the first direction D1 by the first roller 25a and the second roller 25b, and moves the paper P toward the conveyance path of the second conveyance unit 20b, and further by the second conveyance unit 20b. The paper is conveyed in the first direction D1 and discharged from the opening 30 to the paper discharge unit 31.

  The controller 1p maintains the selection plate 25x in a state indicated by a solid line in FIG. 8A during S11 to S13. The controller 1p rotates the selection plate 25x after S13 and before S14 to bring it into the state indicated by the dotted line in FIG. 8A, and the first time point in S14 to S15 (the sheet conveyed in the second direction D2). Until the rear end of P passes through the second contact C2, the selection plate 25x is maintained in the state indicated by the dotted line in FIG. The controller 1p follows the first time point in S15 and before the second time point in S15 (when the leading edge of the sheet P conveyed again in the first direction D1 by the first conveying unit 20a passes through the first contact C1). Then, the selection plate 25x is rotated to the state indicated by the solid line in FIG. 8A, and after the second time point of S15, the selection plate 25x is maintained in the state indicated by the solid line in FIG.

  After S15, the controller 1p ends the routine and shifts the processing to S6 in FIG. After S4 and after S5, the controller 1p turns off the heater 25ah (S6). Thereafter, the controller 1p ends the routine.

  S11 is an example of the first step of the present invention, S12 to S14 are examples of the second step of the present invention, and S15 is an example of the third step and the fourth step of the present invention.

  During S2 to S6, the controller 1p performs ON / OFF control of the heater 25ah so that the temperature of the first roller 25a is maintained within a certain range suitable for drying the paper P. Specifically, the controller 1p determines whether the temperature of the first roller 25a is equal to or higher than the predetermined temperature B based on a signal from a sensor that outputs a signal indicating the temperature of the first roller 25a every predetermined time A. Determine whether. When the temperature of the first roller 25a is lower than the predetermined temperature B, the controller 1p turns on the heater 25ah. When the temperature of the first roller 25a is equal to or higher than the predetermined temperature B, the controller 1p turns off the heater 25ah. The predetermined time A may be set to an arbitrary time.

  The temperature control of the first roller 25a is not limited to the control by the ON / OFF operation as described above. For example, the temperature control of the first roller 25a may be a proportional operation, an integral operation, a control by a differential operation, a PID control (a control in which a proportional operation, an integral operation, and a differential operation are combined) or the like. Further, the predetermined temperature B may be set arbitrarily. The predetermined temperature B is a temperature suitable for drying the paper P in single-sided recording (S4), and in a stage (before S15) before recording is performed on the back surface of the paper P in double-sided recording (S5). It is desirable to set a temperature suitable for drying the paper P. The predetermined temperature B may be set to the same temperature for single-sided recording and double-sided recording, or may be set to different temperatures for single-sided recording and double-sided recording. Further, different temperatures may be set according to the type of recording medium, the image to be recorded on the paper P, and the like.

  By maintaining the temperature of the first roller 25a within a certain range in this way, the paper P passes through the contacts C1 and C2 in both single-sided recording (S4) and double-sided recording (S5). Sometimes, heat is applied to the paper P.

  As described above, according to the present embodiment, when images are recorded on both sides of the paper P, the paper P is moved in the first direction D1 by the first roller 25a and the second roller 25b that rotate in one direction. Heat is applied to the paper P while being conveyed, and then heat is further applied to the paper P while being conveyed in the second direction D2 by the first roller 25a and the third roller 25c that rotate in one direction. it can. That is, according to the present embodiment, in the configuration in which images are recorded on both sides of the paper P and the paper P after image recording is dried by the heat of the rollers 25a to 25c, the rotation direction of the heated rollers 25a to 25c is changed. Since it is not necessary to reversely rotate, the load concerning the mechanism which rotates roller 25a-25c can be reduced.

  Moreover, according to the present embodiment, the number of rollers can be reduced and the configuration can be simplified by sharing the first roller 25a with two paths (the first path and the second path).

  Further, when images are recorded on both surfaces of the paper P, if the paper P after the front surface recording and before the back surface recording is insufficiently dried, the surface contacts the members constituting the third transport unit 20c, and the members Ink may adhere to the surface. On the other hand, in this embodiment, when images are recorded on both sides of the paper P, the first roller 25a and the second roller 25b are used to place the paper P in the first direction with respect to the paper P after front surface recording and before back surface recording. Heat is applied to the paper P while being transported to D1, and further, heat is applied to the paper P while being transported in the second direction D2 by the first roller 25a and the third roller 25c. Thereby, the paper P after front surface recording and before back surface recording can be sufficiently dried to prevent ink from adhering to the member.

  The paper P after front surface recording in the case of single-sided recording and the paper P after front and back surface recording in the case of double-sided recording are conveyed while being heated by the first roller 25a and the second roller 25b, and then the third conveyance. The paper is discharged to the paper discharge section 31 without being transported by the section 20c and the first transport section 20a. It is considered that there is a low possibility that the paper P discharged to the outside of the housing 1a is strongly held between members and the like constituting the transport unit. On the other hand, the paper P after front side recording and before back side recording in the case of double-sided recording is conveyed while being heated by the first roller 25a and the second roller 25b, and then heated by the first roller 25a and the third roller 25c. Be transported. Thereafter, the sheet P is sandwiched by a pair of rollers that configure the third transport unit 20c, and is further sandwiched by a pair of rollers that configure the first transport unit 20a. Therefore, if the paper P is not sufficiently dried, ink can be particularly attached to the pair of rollers constituting the third transport unit 20c and the first transport unit 20a. When ink adheres to the pair of rollers constituting the third transport unit 20c and the first transport unit 20a, the ink may adhere to the paper P that is transported thereafter. In the present embodiment, the paper P after front surface recording and before rear surface recording in the case of double-sided recording is conveyed while being heated by the first roller 25a and the second roller 25b, and then by the first roller 25a and the third roller 25c. It is conveyed while being heated. That is, the paper P is the paper P after the front surface recording in the case of single-sided recording, and the paper P after the front and back recording in the case of double-sided recording (that is, the recording position X again after being recorded at the recording position X). As compared with the paper P) discharged to the paper discharge unit 31, there are many opportunities to be heated. Therefore, in the present embodiment, it is possible to increase the degree of drying of the paper P after front surface recording and before back surface recording in the case of double-sided recording.

  Further, in the case where heat is applied to the paper P by the rollers constituting the second transport unit 20b (for example, the rollers constituting the roller pairs 26 and 27), the rollers rotate while the rollers sandwich the paper P. Since the direction is reversed, a large amount of heat is applied to a part of the paper P, and the degree of dryness of the paper P may be uneven. On the other hand, in the present embodiment, heat is applied to the paper P by the rollers 25a to 25c constituting the third transport unit 20c, and the rollers 25a to 25c hold the paper P while the rollers 25a to 25c sandwich the paper P. Since it is not necessary to reverse the rotation direction, the entire paper P can be dried without unevenness.

  At least the first roller 25a is a drive roller. Since the first roller 25a contacts both the second roller 25b and the third roller 25c, the rotation of the first roller 25a is easily transmitted to both the second roller 25b and the third roller 25c. Therefore, as described above, if at least the first roller 25a is a driving roller, the second roller 25b and the third roller 25c are the first roller 25a even if the second roller 25b and the third roller 25c are driven rollers. It is easy to rotate in accordance with the rotation of the sheet P, and slip hardly occurs between the paper P and each of the first roller 25a, the second roller 25b, and the third roller 25c. Thereby, the disturbance of the image resulting from slip can be suppressed.

  The first roller 25a and the second roller 25b are drive rollers. The roller that comes into contact with the recording surface of the paper P (the surface on which the image is recorded, i.e., the surface to which the ink ejected from the ejection port 14a has adhered) comes into contact with the recording surface via the ink that has adhered to the recording surface. When a slip occurs between the roller and the recording surface, ink spreads on the recording surface and the image is likely to be disturbed. The first roller 25a and the second roller 25b are in contact with the recording surface. The third roller 25c does not contact the recording surface. According to the above configuration, since the second roller 25b is a driving roller in addition to the first roller 25a, not only the slip between the first roller 25a and the recording surface, but also the second roller 25b and the recording surface The slippage between the two can also be suppressed, and the disturbance of the image can be more reliably suppressed.

  A one-way clutch 25bC is provided on the second roller 25b. In this case, when the second roller 25b tries to slip with respect to the paper P, the transmission of the driving force to the second roller 25b is released by the action of the one-way clutch 25bC, and the second roller 25b is synchronized with the conveyance of the paper P. It rotates (rotates at a speed corresponding to the conveyance speed of the paper P. That is, it rotates with the paper P). Thereby, the slip between the 2nd roller 25b and a recording surface can be suppressed more reliably, and disorder of an image can be suppressed more reliably.

  The rollers 25a and 25b are designed to have the same rotational speed. However, practically, since a design error occurs, it is difficult to make the rotation speeds of the rollers 25a and 25b the same. Therefore, in the present embodiment, when the conveyance speed by the first roller 25a becomes larger than the conveyance speed by the second roller 25b, the second roller 25b is moved to the sheet P conveyed by the first roller 25a. Try to turn. Thereby, the slip between the 2nd roller 25b and a recording surface can be suppressed.

  The third roller 25c is a driven roller. Since the third roller 25c does not contact the recording surface, there is no need to use the third roller 25c as a drive roller from the viewpoint of suppressing image disturbance. Therefore, in this case, the configuration can be simplified.

  At least the outer peripheral surface of the first roller 25a has higher water repellency than the outer peripheral surface of the third roller 25c. If the water repellency of the outer peripheral surface of the roller in contact with the recording surface is low, the ink adhering to the recording surface easily moves to the outer peripheral surface of the roller, which may cause the paper P to become dirty. The first roller 25a contacts the recording surface. The third roller 25c does not contact the recording surface. According to the above configuration, at least the outer peripheral surface of the first roller 25a has higher water repellency than the outer peripheral surface of the third roller 25c, so that the ink adhering to the recording surface hardly moves to the outer peripheral surface of the first roller 25a. Contamination of the paper P can be suppressed.

  The outer peripheral surfaces of the first roller 25a and the second roller 25b have higher water repellency than the outer peripheral surface of the third roller 25c. The first roller 25a and the second roller 25b are in contact with the recording surface. According to the above configuration, the outer peripheral surface of the second roller 25b in addition to the first roller 25a has higher water repellency than the outer peripheral surface of the third roller 25c, so that the first roller 25a of the ink adhered to the recording surface Not only the movement to the outer peripheral surface but also the movement of the second roller 25b to the outer peripheral surface can be suppressed, and the contamination of the paper P can be more reliably suppressed.

  The printer 1 includes a heater 25ah configured to heat at least one of the first roller 25a and the second roller 25b. In this case, the drying efficiency of the paper P can be improved by heating at least one of the first roller 25a and the second roller 25b that are in contact with the recording surface.

  The heater 25ah is configured to heat the first roller 25a. In this case, the configuration can be simplified as compared with the case where both the first roller 25a and the second roller 25b are heated. Further, since the first roller 25a contacts both the second roller 25b and the third roller 25c, the heat of the first roller 25a is quickly transmitted to the second roller 25b and the third roller 25c.

  The second roller 25b is configured to have a smaller contact area with the paper P than the third roller 25c. The second roller 25b contacts the recording surface. The third roller 25c does not contact the recording surface. According to the above configuration, it is possible to suppress the ink adhering to the recording surface from moving to the second roller 25b.

  Note that the drying efficiency of the paper P at the first contact point C1 is reduced by the small contact area between the second roller 25b and the paper P. However, since the second roller 25b is in contact with the recording surface immediately after recording and the contact area between the second roller 25b and the paper P is large, the image is likely to be disturbed. Therefore, in this embodiment, the image is disturbed more than the drying efficiency. Priority is given to suppression. On the other hand, since the third roller 25c does not contact the recording surface, the contact area between the third roller 25c and the paper P is increased to improve the drying efficiency. The first roller 25a is in contact with the recording surface, but is in contact with the heated recording surface, not the recording surface immediately after recording, so that even if the contact area between the first roller 25a and the paper P is large, the image Disturbance is less likely to occur than in the case of the second roller 25b.

  The second roller 25b includes four rotating bodies 25b1 arranged at intervals in the main scanning direction (see FIG. 8B). In this case, the contact area with the paper P can be reduced with a relatively simple configuration.

Next, an inkjet printer 101 according to a reference example of the present invention will be described with reference to FIGS. 9 and 10.

The printer 101 has the same configuration as the printer 1 according to the above-described embodiment except for the configuration of the transport unit. Hereinafter, the same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

The transport unit 120 of this reference example includes a first transport unit 20a, a second transport unit 20b, and a third transport unit 120c. The second transport unit 20b is disposed downstream of the recording position X in the first direction D1, transports the paper P transported by the first transport unit 20a in the first direction D1, and transports the paper P to the first direction D1. It is configured to be conveyed in a second direction (direction indicated by a white arrow in FIG. 9) D2 opposite to the direction D1 and to pass through the recording position X, and the roller pairs 24, 26, 27 and guides 29e, 129c. including. The third transport unit 120c transports the paper P, which has been transported in the second direction D2 by the second transport unit 20b and passed the recording position X, in the second direction D2 by the first roller 25a and the second roller 25b, and The paper P transported by the first roller 25a and the second roller 25b is transported in the first direction D1 by the first roller 25a and the third roller 25c in order to send it again to the transport path of the first transport unit 20a. It is configured. The third transport unit 120c includes a roller group 25 including three rollers 25a to 25c, a roller pair 128, and guides 129e, 129f, 129g, and 129h.

  Selection plates 125x and 125y are respectively provided at the branch points of the guide 29b to the guides 129e and 129h (see FIG. 10). Each selection plate 125x rotates around the shafts 125x1 and 125y1 under the control of the controller 1p.

In this reference example , in addition to the roller pairs 26 and 27, the roller pairs 23 and 24 are forward / reverse roller pairs that can rotate forward and backward. When the controller 1p outputs a reverse rotation drive command to the conveyance motor 20M in S14, the roller pairs 23, 24, 26, and 27 rotate in the reverse direction. As a result, the paper P is transported in the second direction D2 by the second transport unit 20b, then sent to the third transport unit 20c, and transported in the second direction D2 while being sequentially sandwiched by the roller pairs 24 and 23. . Thereafter, in S15, the controller 1p conveys the paper P in the second direction D2 by the first roller 25a and the second roller 25b, and guides it to the roller pair 128. Then, the controller 1p sandwiches the paper P by the roller pair 128, and further transports the paper P in the second direction D2 by the first roller 25a and the third roller 25c, thereby transporting the transport path (recording position X) of the first transport unit 20a. In the first direction D1 upstream of the roller pair 23 and immediately upstream of the first direction D1 of the roller pair 23). Then, the controller 1p transports the paper P again in the first direction D1 by the first transport unit 20a, and ejects ink from the ejection port 14a toward the back surface of the paper P when the paper P passes the recording position X. Let Thereby, an image is recorded on the back surface of the paper P. Thereafter, the controller 1p transports the paper P in the first direction D1 by the second transport unit 20b and discharges the paper P from the opening 30 to the paper discharge unit 31.

  The controller 1p maintains the selection plates 125x and 125y in the state indicated by the solid line in FIG. 10 during S4 and during S11 to S13. The controller 1p rotates the selection plate 125x after S13 and before S14 to bring it into a state indicated by a dotted line in FIG. 10, and is conveyed by the third time point (first roller 25a and second roller 25b in S14 to S15). The selection plate 125x is maintained in the state indicated by the dotted line in FIG. 10 until the trailing edge of the sheet P to be passed passes through the first contact C1. After the third time point in S15 and before the fourth time point in S15 (the time point when the leading edge of the paper P conveyed by the first roller 25a and the third roller 25c passes through the second contact C2), the controller 1p The selection plate 125y is rotated to the state indicated by the dotted line in FIG. 10, and the selection plate 125y is maintained in the state indicated by the dotted line in FIG. 10 after the fourth time point of S15.

According to the printer 101 of the present embodiment, although the transport route is different from the printer 1 of the embodiment described above, it is possible to obtain the same effect by the same configuration as the above-described embodiments. Specifically, according to this reference example , when images are recorded on both sides of the paper P, the paper P is heated while being conveyed by the first roller 25a and the second roller 25b that rotate in one direction. After that, the sheet P can be further heated while being conveyed by the first roller 25a and the third roller 25c rotating in one direction. That is, according to this reference example , in the configuration in which images are recorded on both sides of the paper P and the paper P after image recording is dried by the heat of the rollers 25a to 25c, the rotation direction of the heated rollers 25a to 25c is changed. Since it is not necessary to reversely rotate, the load concerning the mechanism which rotates roller 25a-25c can be reduced.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims.

About the transport section:
The conveyance path of the recording medium formed by the conveyance unit is not limited to that shown in the above-described embodiment, and may be arbitrarily changed.
-A conveyance motor and a drive transmission mechanism may be arbitrary structures.
-The several roller pair which comprises a conveyance part does not need to be the same size mutually. For example, the roller pairs 22 to 24 and 26 to 28 in the above-described embodiment do not have to have the same diameter. In this case, it is desirable to control the conveyance speeds of the roller pairs 22 to 24 and 26 to 28 to be the same.
The conveyance unit may include a conveyance belt in addition to the roller pair and the guide.
-A 2nd roller is not limited to including a some rotary body. For example, the second roller may be composed of one rotating body that is long in the main scanning direction, like the first roller 25a and the third roller 25c. In this case, the contact area between the second roller and the recording medium may be reduced by adjusting the contact pressure with the first roller. Further, the second roller may not be configured to have a smaller contact area with the recording medium than the third roller.
-The 1st roller, the 2nd roller, and the 3rd roller do not need to be rotatable only in one direction, and may be rotatable in two directions.
-The water repellency in the outer peripheral surface of a 1st roller, a 2nd roller, and a 3rd roller is not limited to what was shown by the above-mentioned embodiment, You may change arbitrarily.
Which of the first roller, the second roller, and the third roller is a driving roller and which is a driven roller is arbitrary.
-The one way clutch does not need to be provided in the 2nd roller.
-The size of a 1st roller, a 2nd roller, and a 3rd roller is not limited to what was shown in the above-mentioned embodiment, You may change arbitrarily. For example, the diameter of the first roller 25a may not be larger than the diameters of the other rollers 25b and 25c. Further, the diameters of the second roller 25b and the third roller 25c may be different from each other. The diameters of the second roller 25b and the third roller 25c may be different from the diameters of the roller pairs 22-24 and 26-28.
In the above-described embodiment, the first transport unit 20a reverses the direction of the paper P once (that is, reverses so that the surface facing downward in the paper feed tray 1c1 faces upward at the recording position X). However, the present invention is not limited to this. For example, the first transport unit may be configured not to reverse the direction of the recording medium, or may be configured to reverse the direction of the recording medium a plurality of times. For example, when the first transport unit 20a does not reverse the direction of the paper P and when the direction of the paper P is reversed even number of times, the first transport unit 20a does not face downward in the paper feed tray 1c1 but in the paper feed tray 1c1. The surface facing upward is directed upward at the recording position X (that is, it corresponds to “surface” in single-sided recording and double-sided recording). In these cases, not the surface facing upward in the paper feed tray 1c1, but the surface facing downward in the paper feed tray 1c1 corresponds to the “back surface” in double-sided recording.

About the heater :
A heater for heating the second roller may be provided in addition to the heater for heating the first roller. For example, in the above-described embodiment, in the case where a heater for heating the second roller 25b is provided in addition to the heater 25ah for heating the first roller 25a, the first roller 25a that is a roller that contacts the recording surface of the paper P. Since the second roller 25b is directly heated by the heater, high drying efficiency can be ensured .

About the control unit:
The control unit may grasp the position of the recording medium based on the number of rotations of the conveyance motor, and may perform control related to conveyance, based on the signal output from the sensor.
In the above-described embodiment, the control unit selectively performs single-sided recording control and double-sided recording control based on a recording command, but only performs double-sided recording control (does not perform control related to single-sided recording). Also good.
-In the above-mentioned embodiment, a control part judges whether the recording command was received from the external device (S1), and when a recording command was received (S1: YES), it turns ON a heater (S2). However, the control unit may turn on the heater before receiving the recording command. That is, the order of S1 and S2 in the above-described embodiment may be reversed. In this case, for example, the control unit may turn on the heater when the power of the recording apparatus is turned on or when the sleep state of the recording apparatus is released. Further, the control unit may turn on the heater at these times and control the temperature of the roller to be a predetermined temperature C lower than the predetermined temperature B. The control unit may control the temperature of the roller to be a predetermined temperature B after receiving the recording command.

Other:
The liquid discharge head is not limited to the line type, and may be a serial type.
The liquid discharged from the liquid discharge head is not limited to ink, and may be any liquid (for example, pretreatment liquid).
-The actuator for applying energy for discharging liquid from the discharge port is not limited to the piezoelectric type using a piezoelectric element, but other types (for example, a thermal type using a heating element, an electrostatic force is used) (Electrostatic method, etc.).
The number of liquid discharge heads included in the liquid discharge apparatus may be one or more.
The recording medium is not limited to paper and may be any recordable medium.
The liquid ejection apparatus according to the present invention is not limited to a printer, and may be a facsimile machine or a copier.

1: 101 Inkjet printer (liquid ejection device)
1p controller (control unit)
10 Inkjet head (liquid discharge head)
14a discharge port 20a first conveyor 20b second transporter 20c; 120c third conveying unit 25 roller group 25a first roller 25ah heater motor <br/> 25b second roller 25b1 rotator 25c third roller C1 first contact C2 Second contact D1 First direction D2 Second direction P Paper (recording medium)
X Recording position

Claims (9)

A liquid ejection head having a plurality of ejection openings for ejecting liquid;
A first transport unit configured to transport a recording medium in a first direction toward a recording position facing the plurality of ejection ports;
The recording medium is disposed downstream of the recording position in the first direction and is configured to transport the recording medium transported by the first transport unit in the first direction and a second direction opposite to the first direction. A second transport unit;
A first roller configured to rotate in one direction; the first roller at a first contact point downstream of the recording position in the first direction and upstream of the second transport unit in the first direction ; A second roller in contact with the second roller, and a third roller in contact with the first roller at a second contact point downstream of the second transport unit in the second direction and upstream of the recording position in the second direction. The recording medium transported by the first transport unit is transported in the first direction toward the transport path of the second transport unit by the first roller and the second roller, and the second transport A recording medium conveyed in the second direction by the unit is configured to be conveyed in the second direction by the first roller and the third roller in order to send the recording medium again to the conveyance path of the first conveyance unit; A third transport unit;
Configured to heat the first row La, and a heater,
A controller configured to control the liquid ejection head, the first transport unit, the second transport unit, the third transport unit, and the heater ;
The controller is
A first step of controlling the liquid ejection head and the first transport unit so as to record an image on a first surface of a recording medium;
After the first step, controlling the second transport unit so as to transport a recording medium having an image recorded on the first surface in the first direction and the second direction; a second step;
After the second step, controlling the third transport unit to transport the recording medium transported in the second direction toward the recording position; a third step;
After the third step, a fourth step of controlling the liquid discharge head and the first transport unit so as to record an image on a second surface opposite to the first surface of the recording medium. Run,
In the second step, the first roller heated on the second surface when the recording medium having the image recorded on the first surface is conveyed in the first direction and passes through the first contact point. , The heat of the first roller is applied to the second surface, and then the recording medium on which the image is recorded on the first surface is transported in the second direction to pass the second contact. The heater is controlled so that the first roller heated contacts the first surface and heat of the first roller is applied to the first surface when passing. Liquid discharge device.   The liquid ejecting apparatus according to claim 1, wherein at least the first roller is a driving roller.   The liquid ejecting apparatus according to claim 2, wherein the first roller and the second roller are drive rollers.   The liquid ejecting apparatus according to claim 3, wherein a one-way clutch is provided on the second roller.   The liquid ejecting apparatus according to claim 1, wherein the third roller is a driven roller.   The liquid ejection apparatus according to claim 1, wherein at least an outer peripheral surface of the first roller has higher water repellency than an outer peripheral surface of the third roller.   The liquid discharge apparatus according to claim 6, wherein outer peripheral surfaces of the first roller and the second roller have higher water repellency than an outer peripheral surface of the third roller. Said second roller than said third roller, wherein the contact area with the recording medium is configured to be smaller, the liquid ejecting apparatus according to any one of claims 1-7 . The liquid ejecting apparatus according to claim 8 , wherein the second roller includes a plurality of rotating bodies arranged at intervals with respect to the first direction and an orthogonal direction orthogonal to the second direction. .

Images