JP2010047014A - Inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain stable recording quality by preventing a recording part from coming into contact with a recording sheet material, when double side recording is performed using the recording sheet material with warping. <P>SOLUTION: In the double side recording, the fed recording sheet material is carried to the recording part. Recording is conducted on a front surface, followed by carrying the sheet material to a sheet material turning part 2, and then the turned sheet material is carried back to the recording part, so that the recording can be applied to a back surface. An interval between an end surface of a recording head 11 of the recording part and the recording sheet material is adjusted so that it becomes larger when the back surface is recorded, than when the front surface is recorded. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inkjet recording apparatus that is a double-sided recording apparatus for automatically recording on both front and back sides of a recording sheet material that is a recording medium, and in particular, a sheet that inverts a recording medium on which only one side is printed. The present invention relates to an ink jet recording apparatus which is a double-sided recording apparatus provided with a material reversing unit.

  Conventionally, several types of apparatuses have been implemented or proposed as a configuration for performing automatic double-sided recording in a recording apparatus such as an inkjet recording apparatus. After the recording on the front side surface (first surface) of the recording sheet material which is a recording medium, the recording sheet material is conveyed to a sheet material reversing unit (front and back reversing device), and the sheet After the recording sheet material is reversed by the material reversing unit, the recording sheet material is conveyed again to the recording unit, and recording is performed on the back surface (second surface) of the recording sheet material. Among such double-sided recording apparatuses, the inventions disclosed in Patent Document 1 and Patent Document 2 cannot adjust the interval between the recording sheet material and the recording unit, and are always fixedly fixed. . In addition, there is a recording apparatus that can adjust the interval between the recording sheet material and the recording unit and needs to determine the interval between the recording sheet material and the recording unit in advance before starting the recording operation.

US Pat. No. 6,332,068 JP 2002-067407 A

  In any of the above-described conventional examples, the interval between the recording sheet material and the recording portion cannot be changed during the recording operation on one recording sheet material. However, the state of the recording sheet material may not always be the same when recording on the front side surface of the recording sheet material and when recording on the back side surface. In this case, if the recording apparatus is set in an optimum state for recording on the front side surface of the recording sheet material, there is a possibility that the optimum state is not necessarily obtained when recording on the back side surface. The difference in the state of the recording sheet material that is the cause is based on the warp resulting from the recording operation on the first surface of the recording sheet material.

  As in the conventional example described above, the distance between the recording sheet material and the recording portion is constant during recording on the front side surface of the recording sheet material and when recording on the back side surface of the recording sheet material after reversal. If this is the case, there may be a problem when recording on either side. For example, when the interval between the recording portion and the recording sheet material is set to be relatively narrow, the recording portion and the recording sheet material come into contact with each other due to warpage of the recording sheet material, and the recording sheet material is not intended. Ink adhesion may occur, or an external force that impedes accurate conveyance of the recording sheet material may be applied. On the other hand, when the warpage of the sheet material is anticipated in advance and the interval between the recording portion and the recording sheet material is set wider than necessary, the recording quality may be deteriorated, particularly when performing inkjet recording. The recording quality is likely to deteriorate.

  Therefore, the present invention solves the above technical problem, and even when the recording sheet material is warped as a result of the recording operation on the front side surface (first surface), the recording sheet material can be used. An ink jet recording apparatus that is a double-sided recording apparatus that can prevent unintentional ink adhesion and a decrease in the conveyance accuracy of a recording sheet material and can perform a stable recording operation without deteriorating recording quality. The purpose is to provide.

  The present invention relates to a carriage for mounting and moving a recording head for recording on a sheet material by discharging ink, a guide shaft for guiding the movement of the carriage, and conveyance of the sheet material when recording is performed by the recording head. A conveyance roller that conveys the sheet material on the upstream side of the recording head, and a sheet material reversing unit that reverses the front and back of the sheet material on which recording is performed on the first surface by the recording head. By rotating the recording material in the direction opposite to that when recording is performed by the recording head, the sheet material recorded on the first surface is conveyed to the sheet material reversing unit, and recording is performed on the second surface of the sheet material by the recording head. In the ink jet recording apparatus to be performed, the distance between the recording head and the sheet material when recording on the second surface is recorded on the first surface by moving the guide shaft. Characterized by greater than the distance between the recording head and the sheet material when performing the.

  The structure which a guide shaft moves may be sufficient by rotating the cam distribute | arranged to the guide shaft.

  The guide shaft may be supported by the chassis, and movement in the sheet material conveyance direction and carriage movement direction may be restricted.

  The sheet material reversing unit is a second double-side roller for reversing the front and back of the sheet material by contacting the first surface of the sheet material recorded by the recording head, and for reversing the front and back of the sheet material A first double-sided roller disposed on the downstream side of the second double-sided roller in the advancing direction of the sheet material to contact the first surface and reverse the front and back of the sheet material.

  According to the present invention, even when the recording sheet material to be subjected to the automatic double-side recording operation is warped during the recording operation on the first surface, the recording onto the first surface is performed when recording on the second surface. The interval between the recording unit and the recording sheet material can be increased from the time of recording, and unintentional ink adhesion to the recording sheet material is prevented, and stable recording operation is performed without deteriorating the recording quality. be able to.

1 is a perspective view showing an overall configuration of a double-sided recording apparatus according to an embodiment of the present invention. 1 is a side sectional view showing an overall configuration of a double-sided recording apparatus according to an embodiment of the present invention. It is a principal part perspective view which shows the drive mechanism of each lift mechanism of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the pinch roller release mechanism of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the PE sensor lever release mechanism of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the paper passing guide up-and-down mechanism of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is a perspective view showing a carriage up-and-down mechanism of a double-sided recording apparatus according to an embodiment of the present invention. It is explanatory drawing which shows the carriage up-down mechanism of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is a perspective view which shows the drive mechanism of the lift cam shaft of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows each position of the lift mechanism of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is a timing chart which shows operation | movement of the lift mechanism of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the back feed operation | movement (conveyance to a sheet material inversion part) of the recording sheet material of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is a typical sectional side view which shows the structure of the sheet | seat inversion part (automatic duplex unit) of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows operation | movement of the flap in the sheet material inversion part of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is a typical sectional side view which shows the drive mechanism of the sheet material inversion part of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows operation | movement of the drive mechanism of the sheet material inversion part of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows operation | movement of the other example of the drive mechanism of the sheet material inversion part of the double-sided recording apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the registration operation | movement of the front-end | tip of a back side surface in the case of using a thin recording sheet material in the double-sided recording apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the registration operation | movement of the front-end | tip of a back side surface in the case of using a thick recording sheet material in the double-sided recording apparatus which concerns on one Embodiment of this invention. 6 is a flowchart showing a sequence of automatic double-sided recording operation of the double-sided recording apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a control circuit configuration of a double-sided recording apparatus according to an embodiment of the invention. It is a typical sectional side view which shows the other example of the sheet material inversion part of the double-sided recording apparatus which concerns on one Embodiment of this invention.

  Embodiments of the present invention will be specifically described below with reference to the drawings. Throughout the drawings, the same reference numerals are given to the same or corresponding parts.

  FIG. 1 is a perspective view showing the overall configuration of an embodiment of the double-sided recording apparatus of the present invention, and FIG. 2 is a side sectional view showing the overall configuration of the recording apparatus as seen from the direction of arrow A in FIG. Note that the double-sided recording apparatus of this embodiment is a recording apparatus that employs an ink jet recording system that performs recording by ejecting ink toward a recording medium. As the recording medium, recording sheet material 4 made of various materials such as paper, plastic sheet, cloth, metal sheet, or plate member is used.

  As shown in FIGS. 1 and 2, the basic configuration of the double-sided recording apparatus of the present embodiment, that is, the recording unit main body (recording apparatus main body) 1 includes a base 72 and a chassis 10, a paper feeding unit, a sheet material conveying unit, , A recording unit, a maintenance unit, an electric control unit, a sheet material reversing unit (also referred to as “automatic reversing unit” or “automatic duplex unit”) 2 and various lift mechanisms.

  In the present embodiment, the recording sheet material supplied one by one from the sheet feeding unit is conveyed to the recording unit by the sheet material conveying unit, and recording is performed on the first surface (front surface), and then the sheet The material conveying unit conveys the recording sheet material in the reverse direction and sends it to the sheet material reversing unit. The sheet material reversing unit inverts the recording sheet material from the front to the back and conveys it again to the recording unit. On the surface). The distance between the recording unit and the recording sheet material can be changed by a lift mechanism or the like between recording on the front side and recording on the back side.

[Paper Feeder]
The paper feeding unit is an automatic paper feeding unit that pulls out one recording sheet material 4 at a time for each recording operation from a plurality of recording sheet materials 4 stacked on a pressure plate 41 to be described later, and sends the recording sheet material 4 to the sheet material conveying unit. That is, it is a main ASF (Automatic Sheet Feeder) 37. As shown in FIGS. 1 and 2, the main ASF 37 mainly includes an ASF base 38 serving as a base, a pressure plate 41 on which the recording sheet material 4 is stacked, and a side guide provided on the pressure plate 41 so as to be movable. 42, a sheet feeding roller 39 for feeding the recording sheet material 4 on the pressure plate 41, a separation roller 40 for separating the plurality of recording sheet materials 4 one by one, and a sheet feeding roller 39 during a sheet feeding operation. And a return claw 43 for returning the leading end of the recording sheet material 4 that has advanced beyond the nip portion of the separation roller 40 to a predetermined position, and the traveling direction of the recording sheet material 4 from the main ASF 37 is restricted to one direction. ASF flap 44 is provided.

  The pressure plate 41 is in contact with a cam (not shown) connected to the ASF motor 46 and is urged toward the paper feed roller 39 by a pressure plate spring (not shown). Therefore, the pressure plate 41 can take a state of contacting the paper feed roller 39 and a state of being separated from the paper feed roller 39 by the action of the cam.

  The side guide 42 serves as a reference for the position of the recording sheet material 4 in the width direction, and prevents the recording sheet material 4 to be recorded from being displaced in the width direction and feeds it to a predetermined position. It is a guide member.

  The separation roller 40 is pressed against the paper feed roller 39 and has a predetermined return rotational torque in the direction opposite to the conveying direction of the recording sheet material 4, and a plurality of recording sheets are provided between the separation roller 40 and the paper feed roller 39. When the material 4 has been pulled out, the recording sheet material 4 other than the recording sheet material 4 in contact with the paper feed roller 39 can be pushed back toward the original pressure plate 41.

  The return claw 43 reliably pushes back the recording sheet material 4 remaining in the vicinity of the separation roller 40 and the paper supply roller 39 to a predetermined position on the pressure plate 41 at the end of the paper supply operation.

  The ASF flap 44 is urged so as to narrow the sheet material path by an ASF flap spring (not shown). Since the ASF flap 44 is inclined and can swing, the recording sheet material 4 is allowed to pass through the sheet material path in the forward direction (direction from the sheet feeding unit to the recording unit), and in the reverse direction (recording). Entry in the direction from the printing unit to the paper feeding unit is hindered.

[Sheet material conveying section]
As shown in FIGS. 1 and 2, the sheet material conveying unit includes a paper feed roller (conveyance roller) 21, a pinch roller 22, a pinch roller holder 23, a pinch roller spring 24, a paper feed roller pulley 25, and an LF motor. (Line feed motor) 26, code wheel 27, platen 29, first paper discharge roller 30 and second paper discharge roller 31, first spur train 32 and second spur train 33, and spur A base 34 and a guide member (sheet passing guide) 70 are provided.

  A paper feed roller (conveyance roller) 21 is for feeding (conveying) the recording sheet material 4, and a pinch roller 22 held rotatably by a pinch roller holder 23 is paper fed by a pinch roller spring 24. It is pressed against the feed roller 21 and driven. The paper feed roller pulley 25 is fixed to the paper feed roller 21. The paper feed roller 21 is driven by an LF motor 26, and the rotation angle of the paper feed roller 21 is detected by a code wheel 27. The platen 29 supports the recording sheet material 4 so as to face a recording head 11 described later. The first paper discharge roller 30 conveys the recording sheet material 4 in cooperation with the paper feed roller 21, and the second paper discharge roller 31 is provided on the downstream side of the first paper discharge roller 30. . The first spur train 32 is a rotating body that holds the recording sheet material 4 facing the first paper discharge roller 30, and the second spur train 33 faces the second paper discharge roller 31. The rotating body that holds the recording sheet material 4. The first spur train 32 and the second spur train 33 are rotatably held by the spur base 34. The guide member (paper passage guide) 70 guides the leading end of the recording sheet material 4 to the nip portion between the paper feed roller 21 and the pinch roller 22.

  The paper feed roller 21 and the pinch roller 22 constitute a nip portion through which the recording sheet material 4 passes. The center of the pinch roller 22 is attached to a position slightly offset from the center of the paper feed roller 21 in a direction approaching the first paper discharge roller 30. Accordingly, since the approach angle (tangential direction angle) of the recording sheet material 4 is slightly inclined from the horizontal, the pinch roller holder 23 and the guide member 70 ensure that the leading end of the recording sheet material 4 is accurately guided to the nip portion. The formed sheet material path is configured to convey the recording sheet material at an angle.

[Recording section]
As shown in FIGS. 1 and 2, the recording unit includes a recording head 11 that is a recording unit that performs recording by discharging ink to the recording sheet material 4, and an ink tank 12 that stores ink to be supplied to the recording head 11. A carriage 13 for holding the recording head 11 and the ink tank 12 for scanning (main scanning), a guide shaft 14 for guiding and supporting the carriage 13, and a guide rail for guiding and supporting the carriage 13 in parallel with the guide shaft 14. 15, a carriage belt (timing belt) 16 for driving the carriage 13, a carriage motor 17 for driving the carriage belt 16 via a pulley, and the carriage belt 16 is stretched so as to face the pulley of the carriage motor 17. Cord strip for detecting the position of the idler pulley 20 and the carriage 13 And a 8.

  The recording head 11 of the present embodiment is an ink jet recording type head, and although not shown, a plurality of ink flow paths connected to the ink tank 12 are formed, and the ink flow paths face the platen 29 ( It communicates with the discharge port arranged on the discharge port surface. Ink discharge actuators (energy generating means) are arranged inside each of the plurality of discharge ports in a row. As this actuator, for example, an electrothermal transducer (heating element) for generating a liquid film boiling pressure, an electromechanical transducer (electric-pressure transducer) such as a piezo element, or the like is used. The recording head 11 is capable of ejecting ink droplets in accordance with recording data by transmitting a signal of a head driver 307 described later via a flexible flat cable 73.

  The carriage 13 on which the recording head 11 is mounted is guided and supported by a guide shaft 14 fixed to the chassis 10 and a guide rail 15 that is a part of the chassis 10, and is interposed between the carriage motor 17 and the idler pulley 20. When the driving force of the carriage motor 17 is transmitted through the carriage belt 16 that is hung, the reciprocating scanning (moving) is performed in a direction that intersects the conveying direction of the recording sheet material 4 (usually a direction that is orthogonal). The carriage 13 is provided with a CR (carriage) encoder 19. The CR encoder 19 reads the code strip 18 provided on the chassis 10, and the recording head 11 applies the recording sheet material 4 to the recording sheet 4 at an appropriate timing. Provides data for ejecting ink droplets toward. When the recording sheet material 4 is conveyed (paper fed) by a predetermined amount (pitch of one line) by the above-described sheet material conveying unit, the recording head 11 performs recording for one line while the carriage 10 scans. When the recording for one line is completed, the sheet material conveying unit again conveys the recording sheet material 4 by a predetermined amount (pitch of one line). In this way, the recording operation over the entire surface of the recording sheet material 4 is possible by alternately repeating the conveyance of the recording sheet material 4 by the sheet material conveying unit and the scanning of the carriage 13 and the recording by the recording head 11. .

[Maintenance Department]
The maintenance unit shown in FIG. 1 is a maintenance unit 36 that operates when maintaining or recovering the ink ejection performance of the recording head 11 or when distributing ink to the ink flow path of the recording head 11 when the ink tank 12 is replaced. is there. The maintenance unit 36 generates, for example, a capping mechanism including a cap that contacts the discharge port surface (surface on which the discharge ports are arranged) of the recording head 11 to protect the discharge port, and generates negative pressure in the cap capped with the discharge port. A suction recovery mechanism that sucks and discharges ink from the discharge port, and a wiping mechanism that wipes and cleans the peripheral portion of the discharge port, thereby preventing clogging of the discharge port of the recording head 11 and of the recording head 11. The recording operation of the recording head 11 is maintained and recovered to a normal state by eliminating the dirt due to paper dust or the like on the discharge port surface, and ink is sucked when the ink tank 12 is replaced. Therefore, the maintenance unit 36 is installed so as to face the recording head 11 at the home position (standby position) of the carriage 13. When the ink in the discharge port of the recording head 11 is sucked out to refresh, the cap is pressed against the discharge port surface, and the suction pump is driven to make the inside of the cap have a negative pressure, thereby sucking and discharging the ink. To do. In addition, when ink is attached to the discharge port surface after ink suction, or when foreign matter such as paper dust adheres to the discharge port surface, the wiper is brought into contact with the discharge port surface and moved in parallel. Wiping (wiping and cleaning) the discharge port surface to remove deposits such as ink and foreign matter.

[Electric control unit]
As shown in FIG. 21, the electric control unit of each member, which is collected on the control board 301 provided in the double-sided recording apparatus, includes a CPU 310, a ROM 311, a RAM 312, a head driver 307, and a motor driver. A CR (carriage) encoder sensor 19, an LF encoder sensor 28, a PE (paper end) sensor 67, a lift cam sensor 69, a sheet material reversing portion sensor (double-sided unit sensor) 130, a PG sensor 303, and an ASF sensor 305. The detector, the LF motor 26, the CR motor 17, the ASF motor 46, the PG motor 302, the recording head 11, the host device (host computer) 308, and the like are connected. The CPU 310 controls the recording apparatus and issues a control command. The ROM 311 stores control data and the like, and the RAM 312 serves as an area for developing the recording data and the like. The head driver 307 drives the recording head 11, and the motor driver drives each motor. A CR (carriage) encoder sensor 19 is mounted on the carriage 13 and reads the code strip 18. The LF encoder sensor 28 reads the code wheel 27 attached to the chassis 1. The PE sensor 67 detects the operation of the PE sensor lever 66. The lift cam sensor 69 detects the operation of the lift cam shaft 58. The sheet material reversing part sensor (double-sided unit sensor) 130 detects the attachment / detachment of the sheet material reversing part 2. The PG sensor 303 detects the operation of the maintenance unit 36. The ASF sensor 305 detects the operation of the main ASF 37. The ASF motor 46 drives the main ASF 37, and the PG motor 302 drives the maintenance unit 36. The host device 308 is connected via an I / F (interface) 309 that mediates electrical connection, and can send recording data to the recording device.

[Sheet material reversal part]
The sheet material reversing section (also called “automatic duplex unit” or “automatic reversing section”) 2 is automatically placed on the front and back of the recording sheet material, which is a sheet-like cut sheet, without bothering the operator. In order to perform recording, the recording sheet material is reversed. As shown in FIG. 2, the sheet material reversing unit 2 includes a first double-sided roller 108 and a second double-sided roller 109 that are reversing unit rollers for conveying the recording sheet material 4, and a first double-sided roller 108. A first reversing unit pinch roller (first double-sided pinch roller) 112 that is driven, a second reversing unit pinch roller (second double-sided pinch roller) 113 that is driven by the second double-sided roller 109, and a recording sheet The switching flap 104, which is a movable flap that is rotatably supported to determine the traveling direction of the material 4, and the recording sheet material 4 that is rotatably supported and opens and closes when the recording material material 4 exits the sheet material reversing unit 2. And an outlet flap 106.

  The duplex unit 2 sandwiches the recording sheet material 4 that has entered by the second duplex roller 109 and the second duplex pinch roller 113 to change the direction of travel. Further, the duplex unit 2 further changes the first duplex roller 108 and the first duplex roller 108. 2 are conveyed in the direction of arrow d in FIG. 2, and finally the recording sheet material 4 is changed (changed) by 180 degrees and discharged horizontally.

[Lift mechanism]
Furthermore, the double-sided recording apparatus of the present embodiment is provided with various lift mechanisms for adjusting the operation and setting of each unit described above. In the present embodiment, mainly, a release mechanism of the pinch roller 22, a pressure adjusting mechanism of the pinch roller spring 24, a release mechanism of a sheet material detection lever (PE (paper end) sensor lever) 66, and a guide member (sheet passing). A vertical mechanism for the guide 70 and a vertical mechanism for the carriage 13 are provided.

  The pinch roller release mechanism, the pinch roller spring pressure adjustment mechanism, the PE sensor lever release mechanism, the sheet passing guide up / down mechanism, and the carriage up / down mechanism are operated by the rotation of the lift cam shaft 58. That is, as shown in FIG. 3, a pinch roller holder pressing cam 59, a pinch roller spring pressing cam 60, a PE sensor lever pressing cam 61, and a sheet passing guide pressing cam 65 are fixed to the lift cam shaft 58, respectively. Therefore, each cam rotates in synchronization with the rotation of the lift cam shaft 58. The pinch roller holder pressing cam 59 is in contact with the pinch roller holder 23. The pinch roller spring pressing cam 60 serves as an action point of the pinch roller spring 24. The sheet passing guide pressing cam 65 contacts the sheet passing guide 70, and the sheet passing guide 70 is urged in a predetermined direction by a sheet passing guide spring 71. The PE sensor lever pressing cam 61 abuts on a PE (paper end) sensor lever 66 that contacts the recording sheet material 4 to detect the leading edge and the trailing edge, and the PE sensor lever 66 is exposed and shielded from the PE sensor 67. Can be switched. The PE sensor lever 66 is biased in a predetermined direction by a PE sensor lever spring 68. The angle of the lift cam shaft 58 is recognized by the lift cam shaft shielding plate 62 and a lift cam sensor 69 that is switched between an exposed state and a shield state by the lift cam shaft shielding plate 62. That is, the initial position and rotation state of the lift cam shaft 58 are recognized by the lift cam sensor 69 being switched between the exposed state and the shield state by the lift cam shaft shielding plate 62. However, the present invention is not limited to such a configuration, and a mechanism for independently driving each may be employed as necessary.

<Pinch roller release mechanism and pinch roller spring pressure adjustment mechanism>
The release mechanism of the pinch roller 22 operates to release (separate) the pinch roller 22 from the paper feed roller 21 in order to redraw the excess recording sheet material 4 to the pressure plate 41 side.

  The pressure adjusting mechanism of the pinch roller spring 24 is a pressure adjusting mechanism for changing the pressure (spring force) at which the pinch roller 22 is pressed against the paper feed roller 21. In the present embodiment, the entire pinch roller holder 23 is rotated in order to separate (release) the pinch roller 22. When the pinch roller 22 is in pressure contact with the paper feed roller 21, the pinch roller spring 24 biases the pinch roller holder 23. Therefore, when the pinch roller holder 23 is rotated in the release direction, the spring of the pinch roller spring 24 is pressed. It rotates against the force, and there are problems such as an increase in load for releasing the pinch roller holder 23 and an increase in stress applied to the pinch roller holder 23 itself. In order to prevent this, a mechanism (pressure adjusting mechanism) for reducing the pressure of the pinch roller spring 24 when the pinch roller holder 23 is released is provided.

  FIG. 4 is a partial side view schematically showing the operations of the pinch roller release mechanism and the pinch roller spring pressure adjustment mechanism. FIG. 4A shows a state where the pinch roller holder pressing cam 59 is in the initial position, the pressure of the pinch roller spring 24 is in a standard state, and the pinch roller 22 is in pressure contact with the paper feed roller 21. The pinch roller holder 23 is configured such that a pinch roller holder shaft 23a is supported by a bearing portion of the chassis 10 so as to be rotatable and can swing over a predetermined angular range. A pinch roller 22 is rotatably supported at one end of the pinch roller holder 23, and a contact area with the pinch roller holder pressing cam 59 is provided at the other end.

  As shown in FIG. 4A, one end of the pinch roller spring 24 abuts on the pinch roller 22 of the pinch roller holder 23 to become a force point, the other end is supported by the pinch roller spring pressing cam 60, and an intermediate portion is a chassis. The torsion coil spring is supported by 10 support portions. With such a pinch roller spring 24, the pinch roller 22 is pressed against the paper feed roller 21 with a predetermined pressure. When the paper feed roller 21 rotates in this state, the recording sheet material 4 sandwiched between the nip portions of the paper feed roller 21 and the pinch roller 22 can be conveyed.

  When the lift cam shaft 58 rotates in the direction of arrow a in FIG. 4B from the state shown in FIG. 4A, the pinch roller holder pressing cam 59 contacts the pinch roller holder 23 as shown in FIG. The pinch roller holder 23 is gradually swung in the direction of the arrow b, and the pinch roller 22 is released (separated) from the paper feed roller 21. In the state shown in FIG. 4B, the small diameter portion of the pinch roller spring pressing cam 60 contacts the pinch roller spring 24, and the twist angle θ2 of the pinch roller spring 24 is greater than the twist angle θ1 in the state shown in FIG. Therefore, the spring load is reduced, and the pinch roller holder 23 is hardly applied with a load (stress). In this state, a predetermined amount of gap H is formed between the paper feed roller 21 and the pinch roller 22, and the leading end of the recording sheet material 4 can be easily inserted into the nip portion only by roughly guiding the recording sheet material 4. It is possible.

  When the lift cam shaft 58 further rotates in the direction of arrow a from the state shown in FIG. 4B, the contact between the pinch roller holder pressing cam 59 and the pinch roller holder 23 is released, as shown in FIG. The pinch roller holder 23 rotates in the direction of arrow c in FIG. 4C to return to the original state (the state shown in FIG. 4A), and the abutting portion of the pinch roller spring pressing cam 60 with the pinch roller spring 24 4 is a portion of a radius having an intermediate size between the contact portion in the state shown in FIG. 4A and the contact portion in the state shown in FIG. Therefore, the state shown in FIG. 4C is a light pressure contact state in which the pinch roller 22 is in pressure contact with the paper feed roller 21 as in the state shown in FIG. Since the twist angle θ3 of the pinch roller spring 24 is slightly smaller than the twist angle θ1 in the state shown in FIG. 4A, the force that presses the pinch roller 22 against the paper feed roller 21 is slightly smaller.

  During one rotation of the lift cam shaft 58, the pinch roller release mechanism and the pinch roller spring pressure adjustment mechanism change from the state shown in FIG. 4 (a) to the state shown in FIG. 4 (b) and the state shown in FIG. 4 (c). Then, it returns to the standard state shown in FIG. By adjusting the rotational position of the lift cam shaft 58 and taking the state shown in FIG. 4C, when the recording sheet material 4 thicker than usual is sandwiched between the paper feed roller 21 and the pinch roller 22, It is possible to prevent the twisting angle of the pinch roller spring 24 from becoming larger than usual, thereby increasing the generated load on the pinch roller holder 23. Therefore, in the present embodiment, by adjusting the rotational position of the lift cam shaft 58 and using the standard state shown in FIG. 4A and the light pressure contact state shown in FIG. For both the sheet material 4 and the thick recording sheet material 4, the rotational load applied to the shaft of the paper feed roller 21 can be leveled.

<PE sensor lever release mechanism>
A release mechanism of the PE sensor lever 66 that is a sheet material detection lever will be described. The PE sensor lever 66 performs recording so that the position of the leading edge and the trailing edge of the recording sheet material 4 can be accurately detected when the recording sheet material 4 advances in the forward direction (the direction from the paper feeding unit to the recording unit). It is attached so as to swing at a predetermined angle with respect to the surface of the sheet material 4 for use. For this reason, when the recording sheet material 4 travels in the reverse direction (the direction from the recording unit to the paper feeding unit), the end of the recording sheet material 4 may be caught by the PE sensor lever 66, There is a technical problem that the leading edge of the PE sensor lever 66 bites into the recording sheet material 4. Therefore, in the present embodiment, the release mechanism is configured so that the PE sensor lever 66 is separated from the sheet material path and does not contact the recording sheet material 4 until the recording sheet material 4 is partially reversed. Has been.

  FIG. 5 is a partial side view schematically showing the operation of the PE sensor lever up-and-down mechanism. FIG. 5A shows a state where the PE sensor lever pressing cam 61 is in the initial position and the PE sensor lever (sheet material detection lever) 66 is free. The PE sensor lever 66 is rotatably supported by a PE sensor lever shaft 66a supported by a bearing portion of the chassis 10. In the state shown in FIG. 5A, the PE sensor lever 66 is biased by the PE sensor lever spring 68, and the shielding plate portion of the PE sensor lever 66 shields the PE sensor 67. In this state, when the recording sheet material 4 passes the position of the PE sensor lever 66, the PE sensor lever 66 is pushed by the end portion of the recording sheet material 4 and rotates clockwise, and the PE sensor 67 is shielded by the shielding plate portion. Will be exposed. Thereby, the presence of the recording sheet material 4 can be detected. The leading and trailing edges of the recording sheet material (recording sheet material) can be detected in the light-shielded and exposed state.

  FIG. 5B is a partial side view schematically showing a state in which the PE sensor lever 66 is locked. As shown in FIG. 5B, when the PE sensor lever pressing cam 61 rotates in the direction of arrow a, the cam follower portion of the PE sensor lever 66 is pushed up and swings in the direction of arrow b. In this state, the end of the PE sensor lever 66 (the portion where the recording sheet material 4 abuts) is hidden inside the pinch roller holder 23, and the recording sheet 4 also passes when the recording sheet material 4 passes. The material 4 and the PE sensor lever 66 do not contact each other. Therefore, even if the recording sheet material 4 is conveyed in the direction of the arrow b in this state, the recording sheet material 4 does not hit the PE sensor lever 66 to cause a problem such as jamming.

  The release mechanism of the PE sensor lever 66 can be replaced with other means or configuration. That is, as a means for solving the above-described technical problem, a roller or the like is provided at the tip of the PE sensor lever 66, and even if the recording sheet material 4 travels in the reverse direction, the roller can rotate and pass smoothly. In this way, means for solving the technical problem described above may be employed. Further, when the PE sensor lever 66 has a large swinging angle and the recording sheet material 4 is conveyed in the reverse direction, the PE sensor lever 66 swings in the reverse direction to the normal direction. You may employ | adopt the means to solve a subject.

<Feeding guide up / down mechanism>
The vertical mechanism of the paper passing guide 70 will be described. Normally, the paper passing guide 70 guides the recording sheet material 4 fed from the main ASF 37 to the paper feed roller 21, and as described above, the recording sheet material 4 is LF along a path slightly inclined with respect to the horizontal. It is located at an angle slightly upward from the horizontal from the position of the LF roller 21 so as to guide smoothly to the nip portion of the roller 21 (see FIGS. 2 and 6A). However, if the recording sheet material 4 is conveyed in the direction of the arrow b (reverse direction) in FIG. 2, it is guided again toward the main ASF 37 in the present embodiment. In order to guide the recording sheet material 4 recorded on this surface to the sheet material reversing portion 2, it is necessary to smoothly guide it to a horizontal path. Therefore, in order to change the angle so that the sheet passing guide 70 is horizontal, an up / down mechanism for moving the sheet passing guide 70 up and down is provided.

  FIG. 6 is a partial side view schematically showing the operation of the sheet passing guide up / down mechanism. FIG. 6A shows the raised state of the sheet passing guide 70. As shown in FIG. 6A, the sheet passing guide 70 is normally urged in a direction to be lifted by a sheet passing guide spring 71 which is an elastic member, and a position where it abuts against a stopper (not shown) is set as the raised position. ing. When the recording sheet material 4 fed from the main ASF 37 passes, the sheet passing guide 70 is kept in the raised state by the action of the sheet passing guide spring 71. However, the sheet passing guide 70 is configured to be able to descend against the spring force of the sheet passing guide spring 71 when a larger force than usual is applied.

  FIG. 6B shows the lowered state of the sheet passing guide 70. As shown in FIG. 6B, when the sheet passing guide pressing cam 65 fixed to the lift cam shaft 58 rotates in the direction of arrow a, the sheet passing guide pressing cam 65 is a part of the sheet passing guide 70. The guide cam follower 70a is abutted and gradually pressed. As a result, the paper passing guide 70 is rotated in the direction of the arrow b and is pushed down against the spring force of the paper passing guide spring 71. In this lowered state, the portion of the sheet passing guide 70 that faces the sheet material path is substantially horizontal, and the sheet material path is almost completely straight. As a result, when the recording sheet material 4 is conveyed in the reverse direction from the paper feed roller 21, the recording sheet material 4 is conveyed horizontally, and the recording on the front side surface of the recording sheet material 4 has already been performed. The portion is not pressed against the upper surface (ceiling portion) of the sheet material path.

<Carriage lifting mechanism>
The vertical mechanism of the carriage 13 is such that when the pinch roller holder 23 is in a released state (a state away from the paper feed roller 21), the tip of the pinch roller holder 23 approaches the carriage 13, and the two come into contact with each other. This is to prevent the movement in the scanning direction from being hindered. Therefore, the vertical mechanism of the carriage 13 raises the carriage 13 in synchronization with the release operation of the pinch roller holder 23. The vertical mechanism of the carriage 13 can also be applied to other uses. For example, when recording on a thick recording sheet material, the recording head 11 as a recording unit does not come into contact with the recording sheet material. It can also be used when the recording head 11 is moved for the purpose of retracting.

  FIG. 7 is a perspective view showing the carriage vertical mechanism. As shown in FIG. 1, the guide shaft 14 is supported on both sides of the chassis 10, and a right guide shaft cam 14a and a left guide shaft cam 14b are attached. The gear portion of the right guide shaft cam 14 a is connected to the lift cam gear 52 via the cam idler gear 53. The guide shaft 14 is fitted in the guide elongated hole 57 in the vertical direction and can move in the arrow Z direction in FIG. 7, but movement in the arrow X direction and the Y direction is restricted.

  In the carriage up-and-down mechanism shown in FIG. 7, the guide shaft 14 is normally urged downward (in the direction opposite to the arrow Z) by the guide shaft spring 74. When the cam idler gear 53 rotates, the right guide shaft cam 14a and the left guide shaft cam 14b come into contact with the guide inclined surface 56, so that the guide shaft 14 moves in the vertical direction while rotating.

  FIG. 8 is a partial side view schematically showing the operation of the carriage vertical mechanism. FIG. 8A shows a case where the carriage 13 is in the first carriage position which is the standard position. In this state, the guide shaft 14 is positioned by being abutted against the lower limit of the guide long hole 57 of the chassis 10, and the guide shaft cam 14a and the guide slope 56 are not in contact with each other. In the first carriage position, a relatively short interval S1 is generated between the end surface (discharge port surface) of the recording head 11 and the recording sheet material 4. This interval S1 is suitable for recording the recording sheet material 4 having a standard thickness and material in a normal state, and is an interval (first interval) calculated so as to achieve good recording quality. It is.

  When the lift cam shaft 58 rotates from the first carriage position, the lift cam gear 52 fixed to the lift cam shaft 58 rotates, and the right guide shaft cam gear 14c rotates via the cam idler gear 53 engaged with the lift cam gear 52. Then, as shown in FIG. 8B, the carriage 13 moves to a slightly higher second carriage position. At this time, if the lift cam gear 52 and the right guide shaft cam gear 14c have the same number of teeth, the lift cam shaft 58 and the guide shaft 14 rotate in substantially the same angle in the same direction. The reason why they do not rotate at exactly the same angle is that the lift cam gear 52 and the cam idler gear 53 have their rotation axes fixed, while the right guide shaft cam gear 14c moves up and down the guide shaft 14 itself. This is because the distance between gears varies.

  Thus, when the lift cam shaft 58 rotates in the direction of arrow a in FIG. 8, the guide shaft 14 rotates in the direction of arrow b. As a result of this rotation, the right guide shaft cam 14a and the left guide shaft cam 14b each come into contact with the fixed guide slope 56, and the moving direction of the guide shaft 14 is only in the vertical direction by the guide slot 57 of the chassis 10 as described above. Therefore, the guide shaft 14 moves to the second carriage position. In this second carriage position, an interval S2 (second interval) slightly longer than the interval S1 occurs between the end surface (discharge port surface) of the recording head 11 and the recording sheet material 4. The second carriage position is preferably set when the recording sheet material 4 is largely deformed and the recording sheet material 4 and the recording head 11 come into contact with each other at the first carriage position.

  When the lift cam shaft 58 further rotates from the second carriage position, the larger radius portion of the cam surfaces of the right guide shaft cam 14a and the left guide shaft cam 14b abuts against the guide slope 56, and the guide shaft 14 is at a higher position ( Move to the third carriage position shown in FIG. In the first carriage position, a long interval S3 is generated between the end surface (discharge port surface) of the recording head 11 and the recording sheet material 4. This third carriage position is suitable when, for example, a recording sheet material 4 that is thicker than usual is used. In FIGS. 8A to 8C, the intervals S1 to S3 are enlarged for easy understanding.

<Driving mechanism of lift cam shaft>
FIG. 9 is a perspective view of the lift mechanism described above, that is, the pinch roller release mechanism, the pinch roller spring pressure adjustment mechanism, the PE sensor lever release mechanism, the paper feed guide vertical mechanism, and the lift cam shaft drive mechanism that operates the carriage vertical mechanism. Will be described with reference to FIG.

  In the present embodiment, an ASF motor 46 that drives the main ASF 37, which is a drive source of the lift cam shaft 58 (in FIG. 9, the upper half is omitted to show gears), and an ASF that operates in conjunction with the main ASF 37. A planetary gear 49, a lift input gear 50 that engages with the ASF planetary gear 49, a lift reduction gear train 51 that transmits power from the lift input gear 50 while decelerating, and a lift cam shaft 58 that moves the pinch roller holder 23 up and down. The lift cam gear 52 that is directly connected to the lift cam shaft 58, the guide shaft spring 55 that biases the guide shaft 14 to one side, the guide shaft gear 53 that is directly connected to the guide shaft 14, and the cam of the guide shaft gear 53 A sliding guide slope 56 is provided.

  The ASF motor 46 controls the direction and amount of rotation thereof to operate the main ASF 37, and at the center of the ASF pendulum arm 47 and the ASF pendulum arm 47 located at the next stage of the gear attached to the ASF motor 46. The attached ASF sun gear 48, the ASF planetary gear 49 attached to the end of the ASF pendulum arm 47 and engaged with the ASF sun gear 48, the pendulum lock cam 63 fixed to the lift cam shaft 58, and the pendulum lock cam 63 The lift cam shaft 58 is operated via a pendulum lock lever 64 that swings when acted.

  The driving force transmission direction is determined by the rotation direction of the ASF motor 46. When operating the lift cam shaft 58, the ASF motor 46 is rotated in the direction of arrow a in FIG. Then, the gear attached to the ASF motor 46 rotates the ASF sun gear 48. Since the ASF sun gear 48 and the ASF pendulum arm 47 are rotatably contacted with a predetermined friction force, the ASF pendulum arm 47 swings in the rotation direction of the ASF sun gear 48 (arrow b direction). Then, the ASF planetary gear 49 engages with the next-stage lift input gear 50. As a result, the driving force of the ASF motor 46 is transmitted to the lift cam gear 52 via the lift reduction gear train 51. At this time, since the ASF pendulum arm 47 swings in the direction of the arrow b, the driving force to the gear train that drives the main ASF 37 is cut off.

  On the other hand, when driving the main ASF 37, by rotating the ASF motor 46 in the direction opposite to the arrow a in FIG. 9, the ASF pendulum arm 47 swings in the direction opposite to the arrow b, as described above. As a result, the engagement between the ASF planetary gear 49 and the lift input gear 50 is released, and the other ASF planetary gear 49 provided on the ASF pendulum arm 47 engages with the gear train connected to the main ASF 37, The ASF 37 is driven.

  In the present embodiment, a so-called stepping motor is used as the ASF motor 46, and this is controlled in an open loop. It goes without saying that closed loop control may be performed by using an encoder for a DC motor or the like.

  When a planetary gear mechanism is used for driving force transmission, when the driven side has a negative load, that is, the non-driven one of the lift mechanism and the main AFS 37 is released without receiving a load. In this case, the pendulum lock lever 64 is moved and the gear is disengaged, so that there is a possibility that a so-called advance operation occurs in which the phase of the driven side is advanced from that of the driving source. In order to prevent this, a pendulum lock cam 63 and a pendulum lock lever 64 are provided in the present embodiment. When the lift cam shaft 58 is within a predetermined angle range, the pendulum lock lever 64 swings in the direction of arrow c in FIG. 9 due to the cam surface shape of the pendulum lock cam 63, and the pendulum lock lever 64 engages with the ASF pendulum arm 47. Then, the main ASF 37 is fixed so as not to return to the driving side. As a result, the ASF planetary gear 49 is always in mesh with the lift input gear 50, so that the ASF motor 46 and the lift cam shaft 58 always rotate in synchronization. When the pendulum lock cam 63 returns to the predetermined angle range, the pendulum lock lever 64 returns in the direction opposite to the arrow c, the ASF pendulum arm 47 is unlocked, and the ASF motor 46 is rotated in the reverse direction. It returns to the state where the drive can be transmitted.

  The drive mechanism of the lift cam shaft 58 described above enables the release of the pinch roller 22, the locking of the PE sensor lever 66, the pressure adjustment of the pinch roller spring 24, the vertical movement of the paper feed guide 70, and the vertical movement of the carriage 13.

<Correlation of lift mechanism>
Next, how these five types of movable mechanisms (lift mechanisms) operate in correlation will be described. FIG. 10 is a schematic partial side view showing operations of the carriage 13, the pinch roller 22, the PE sensor lever 66, and the paper passing guide 70.

  FIG. 10A shows a case where the lift mechanism is in the first position. In this state, the pinch roller 22 is in pressure contact with the paper feed roller 21, the PE sensor lever 66 is in a free state, and the pinch roller spring 24 (see FIG. 4) is in pressure contact with normal pressure. The guide 70 is in the raised state, and the carriage 13 is in the first carriage position.

  The state shown in FIG. 10A is used for a recording operation using the normal recording sheet material 4 or for removing registration after the recording sheet material is reversed in the sheet material reversing unit (automatic duplex unit) 2. It is a position to be. As described above, the carriage 13 is guided and supported so as to be movable along the guide shaft 14, and can be moved up and down by moving the guide shaft 14 up and down along the guide long holes 57 formed in the chassis 10. It is configured.

  FIG. 10B shows a case where the lift mechanism is in the second position. In this state, the pinch roller 22 is in pressure contact with the paper feed roller 21, the PE sensor lever 66 is in a free state, the pinch roller spring 24 is in pressure contact with normal pressure, and the paper feed guide 70 is in a raised state. The carriage 13 is in the second carriage position. In this state, compared to the first position of the lift mechanism, only the height position of the carriage 13 is different. This state is used when the recording sheet material 4 is largely deformed and the recording sheet material 4 and the recording head 11 may be rubbed, or when a slightly thick recording sheet material 4 is used. It is a position.

  FIG. 10C shows a case where the lift mechanism is in the third position. In this state, the pinch roller 22 is released (separated) from the paper feed roller 21 and has a predetermined clearance, and the PE sensor lever 66 is retracted upward and locked (locked). The pinch roller spring 24 is in a state where the pressure contact force is weakened, the paper passing guide 70 is in a lowered state, and the carriage 13 is at the highest third carriage position. Compared with the second position of the lift mechanism, all the states are changed, the sheet material path is completely opened, and the recording sheet material 4 can be pulled in. This state is a position used when the recording sheet material 4 is conveyed in the direction of arrow b in FIG. 2 after the surface recording of the recording sheet material 4 is completed, or when the thick recording sheet material 4 is inserted. .

  FIG. 10D shows a case where the lift mechanism is in the fourth position. In this state, the pinch roller 22 is in pressure contact with the paper feed roller 21, the PE sensor lever 66 is retracted upward and locked (locked), and the pinch roller spring 24 is in pressure contact with a slightly weak pressure. The sheet passing guide 70 is in the lowered state, and the carriage 13 is at the highest third carriage position. Compared with the third position of the lift mechanism, this state changes so that the pinch roller 22 is returned to the pressure contact state and the pressure with which the pinch roller spring 24 presses is slightly weakened. In this state, after the retraction of the recording sheet material 4 at the time of automatic double-sided recording, the recording sheet material 4 is conveyed toward the automatic double-side unit 2 that is a sheet material reversing unit, or the thick recording sheet material 4 is This is the position used when recording.

  In the present embodiment, in view of the operation of the recording apparatus, the lift mechanism is located at any one of the four positions shown in FIGS. 10A to 10D and is limited to the four positions. This simplifies the mechanism. That is, while the lift cam shaft 58 makes one rotation, the position is changed by circulating from the first position → the second position → the third position → the fourth position → the first position.

  FIG. 11 shows a timing chart showing the operation state of the lift mechanism described above, and the contents shown in FIGS. 4 to 10 can be understood more easily by referring to the timing chart of FIG. The horizontal axis in FIG. 11 indicates the angle of the lift cam shaft 58 in a range of 360 degrees, and indicates the position of each mechanism element at each angular position. By operating the lift cam shaft 58 and the guide shaft 14 in synchronization, the angle of the lift cam shaft 58 is detected by the lift cam sensor 69 (see FIG. 3), and only the rotation angle of the ASF motor 46 (see FIG. 21) is controlled. Thus, a plurality of mechanisms can be operated simultaneously.

  However, this invention is not limited to this, You may comprise so that each mechanism element may operate | move independently suitably. Further, the pressure adjusting mechanism of the pinch roller spring 24 is not essential, and can be omitted when the rigidity of the pinch roller holder 23 is sufficiently high or when the load fluctuation of the LF motor 26 is not a problem. In addition, even if the paper passing guide 70 is horizontal due to the arrangement of the main ASF 37 or the like, any mechanism that can guide the leading edge of the recording sheet material to the nip portion of the paper feed roller 21 can be used without the vertical mechanism of the paper passing guide 70. Good.

[Description of operation of this embodiment]
Next, a method for recording on a recording sheet material by the double-sided recording apparatus of the present embodiment will be described. First, the characteristic steps of the recording method in the present embodiment will be described.

<Paper feeding operation>
When recording data is sent from the host device 308 shown in FIG. 21 to the control board 301 via the interface (I / F) 309, the RAM 312 stores the recording data, and the CPU 310 issues a recording operation start command to start the recording operation. To do. When the recording operation starts, a paper feeding operation is first performed. 1 and 2, the main ASF 37 serving as a paper feed unit is pulled out from the recording sheet material 4 stacked on the pressure plate 41 one by one for each recording operation, and is sent to the sheet material conveyance unit. Specifically, the ASF motor 46 rotates in the forward direction in response to the sheet feeding operation start command, and the power rotates the cam holding the pressure plate 41 through a gear train (not shown). When the cam is rotated by the rotation of the ASF motor 46, the pressure plate 41 is released from the state pressed by the cam, and is urged toward the paper feed roller 39 by the action of a pressure plate spring (not shown). At the same time, the paper feed roller 39 rotates in the direction in which the recording sheet material is conveyed, and conveyance of the uppermost one of the recording sheet materials stacked on the pressure plate 41 is started.

  However, depending on conditions such as the frictional force between the sheet feeding roller 39 and the recording sheet material 4 and the frictional force between the recording sheet materials 4, a plurality of recording sheet materials 4 may be sent out simultaneously. is there. In that case, a separation roller 40 is pressed against the paper feed roller 39 and has a predetermined return rotational torque in a direction opposite to the conveying direction of the recording sheet material 4, and the separation roller 40 is applied to the paper feed roller 39. The recording sheet material 4 other than the recording sheet material 4 in contact is pushed back toward the original pressure plate 41. With such an operation, only one sheet of recording material 4 is conveyed to the sheet material conveying unit. At the end of the paper feeding operation, the separating roller 40 is released from the pressure contact state with the paper feeding roller 39 by the operation of the cam and is separated by a predetermined distance. The recording sheet material 4 returned by the above is surely pushed back to a predetermined position on the pressure plate 41.

<Sheet material conveyance operation>
When one recording sheet material 4 is conveyed from the main ASF 37, the front end of the recording sheet material 4 is urged so as to narrow the sheet material path by an ASF flap spring (not shown). 44 (see FIG. 2), but the ASF flap 44 is pushed away and passes. When the recording operation of the recording sheet material 4 is completed and the trailing edge of the recording sheet material passes through the ASF flap 44, the ASF flap 44 returns to the original biased state and the sheet material path is closed. Even if 4 is slightly conveyed in the reverse direction, it does not return to the main ASF 37.

  The single recording sheet 4 conveyed from the sheet feeding unit in this way is conveyed toward the nip portion between the paper feed roller (conveying roller) 21 and the pinch roller 22 of the sheet material conveying unit.

  The recording sheet material 4 conveyed by the main ASF 37 is abutted against the nip portion between the stopped paper feed roller 21 and the pinch roller 22. At this time, the recording sheet material 4 is looped between the paper feed roller 39 and the paper feed roller 21 by the main ASF 37 transporting the recording sheet material 4 by a distance slightly longer than the length of the predetermined sheet material path. Bend. The front end of the recording sheet material 4 is pressed against the nip portion of the paper feed roller 21 and the pinch roller 22 by the force that the loop (bending) tries to return straight. As a result, the leading end of the recording sheet material 4 becomes parallel to the paper feed roller 21 and the so-called registration removing operation is completed. After the registration operation is completed, the LF motor (conveyance motor) 26 rotates (forward) in the direction in which the recording sheet material 4 is moved in the forward direction (the direction in which the recording sheet 4 advances toward the first paper discharge roller 30). Start).

  Thereafter, the supply of the driving force to the paper feed roller 39 is stopped, and the paper feed roller 39 rotates following the recording sheet material 4. At this time, the recording sheet material 4 is conveyed only by the paper feed roller 21 and the pinch roller 22.

  The leading edge of the recording sheet 4 gradually reaches the nip portion of the first paper discharge roller 30 and the first spur train 32 and the nip portion of the second paper discharge roller 31 and the second spur train 33. The peripheral speeds of the first paper discharge roller 30 and the second paper discharge roller 31 are set substantially equal to the peripheral speed of the paper feed roller 21, and the paper feed roller 21, the first paper discharge roller 30, and the second discharge roller 31 are set. Since it is connected to the paper roller 31 by a gear train (not shown), the first paper discharge roller 30 and the second paper discharge roller 31 rotate in synchronization with the paper feed roller 21, thereby recording sheets. The material 4 is stably conveyed to the recording unit without being loosened or pulled.

<First recording operation>
In the recording unit, recording is first performed on the front side surface of the recording sheet material 4 that has been conveyed. That is, while the recording sheet material 4 is temporarily stopped, the carriage 13 on which the recording head 11 is mounted is driven by the carriage motor 17 via the carriage belt 16 while being guided by the guide shaft 14 and the guide rail 15. Is transmitted to and from the head driver 307 shown in FIG. 21 via the flexible flat cable 73 while being reciprocally scanned (moved) in a direction intersecting the conveyance direction of the recording sheet material 4 (usually a direction orthogonal). In accordance with the transmitted recording signal, the recording head 11 discharges ink onto the recording sheet material and performs recording for one line. When the recording for one line is completed, the sheet material conveying unit conveys (paper feeds) the recording sheet material 4 along the rib provided on the platen 29 by the pitch of one line. By alternately repeating the scanning of the carriage and the ejection of ink from the recording head 11 and the conveyance of the recording sheet material 4 at a pitch of one line, the recording operation on the entire front surface of the recording sheet material is performed.

  Here, the recording range at the time of front side recording will be described. The recording head 11 has a discharge port area N (also referred to as “recording area” or “ink discharge area”) shown in FIG. 2 between the paper feed roller 21 and the first paper discharge roller 30. The discharge port region N is disposed in the immediate vicinity of the nip portion of the paper feed roller 21 due to the convenience of the arrangement of the ink flow path to the discharge port and the convenience of the wiring to the actuator (discharge energy generating means) that discharges ink. That is usually difficult. Therefore, in the range where the recording sheet material 4 is sandwiched between the paper feed roller 21 and the pinch roller 22, the recording sheet material 4 ends downstream of the nip portion of the paper feed roller 21, for example, at a position separated by a length D 1 shown in FIG. The recording head 11 must be arranged so that the portion comes, and as a result, the recording sheet material 4 cannot perform recording in a region in which the length D1 is added to the portion sandwiched between the nip portions.

  In this embodiment, in order to reduce such a non-recordable blank area at the lower end of the recording sheet material 4, the recording sheet material 4 is detached from the nip portion of the paper feed roller 21 and the pinch roller 22, and Recording is continued so that the first discharge roller 30 and the second discharge roller 31 are conveyed only by being sandwiched between the leading ends. This enables a recording operation in which the margin area at the lower end is substantially zero. However, if the recording sheet material is conveyed in the direction of arrow b in FIG. 2 to the sheet material reversing section 2 after recording on the front side surface in this way, the paper feed roller 21 and the pinch are pinched. It is difficult to smoothly insert the rear end portion of the recording sheet material 4 into the nip portion of the roller 22, and so-called jamming is likely to occur. In this embodiment, in order to avoid jamming, the pinch roller release mechanism described above is used to release (separate) the pinch roller 22 from the paper feed roller 21 as shown in FIG. A gap is formed, and the end of the recording sheet material 4 is drawn into the gap, and then the pinch roller 22 is pressed against the paper feed roller 21 again as shown in FIGS. The recording sheet material can be conveyed in the direction of arrow b.

<Retraction action>
As described above, in the double-sided recording method, after the recording of the front side surface is completed, the recording sheet material 4 is conveyed in the direction of arrow b in FIG. 2 along the horizontal path provided below the main ASF 37. Since the double-sided unit 2 that is the sheet material reversing unit is disposed behind the main ASF 37, the recording sheet material 4 is guided into the double-sided unit 2 from a horizontal path and conveyed in the direction of arrow c in FIG.

  FIG. 12 is a schematic side view for explaining a process of drawing the recording sheet material again into the nip portion of the paper feed roller 21 after the recording on the front side surface of the recording sheet material 4 is completed. In FIG. 12A, the recording on the front side surface of the recording sheet material 4 is completed, and the recording sheet material 4 includes the first paper discharge roller 30, the first spur train 32, and the second paper discharge. A state in which the roller 31 and the second spur train 33 are sandwiched is shown. The first spur train 32 and the second spur train 33 are constituted by rotating bodies that are driven to rotate by being pressed by the corresponding paper discharge rollers 30 and 31. At this time, the lift mechanism is in the state of the first position or the second position described above.

  As described above, when the recording sheet material 4 is advanced to the state shown in FIG. 12A and recording is performed, the ejection port array (“ejection nozzle array”) of the recording head 11 is filled up to the rear end portion of the recording sheet material 4. ”Or“ ink ejecting portion ”) can be opposed to each other, so that recording can be performed without creating a blank area at the bottom of the recording sheet material 4.

  Next, the lift mechanism is shifted to the third position as shown in FIG. 12B, and a predetermined amount of gap is formed between the pinch roller 22 and the paper feed roller 21. Thereby, even if the rear end of the recording sheet material 4 is somewhat wavy or warps upward, it can be easily pulled in. At this time, since the pinch roller holder 23 and the carriage 13 do not interfere with each other, the carriage 13 may be located at any position in the main scanning direction.

  The first sheet discharge roller 30 is rotated in the direction of the arrow from the state of FIG. 12A, and the recording sheet material 4 is conveyed in the direction of arrow b in FIG. 2 (hereinafter, the recording sheet material 4 is conveyed in this direction). This is referred to as “back feed” or “reverse conveyance”), and is moved to the bottom of the pinch roller 22 and stopped as shown in FIG. The reason for stopping in this state is mainly that the recording apparatus of the present embodiment employs a wet inkjet recording method, and therefore the recorded surface (upper surface in FIG. 12) of the recording sheet material 4 is immediately after the recording operation. If the pinch roller 22 and the paper feed roller 21 are in contact with each other immediately after being wet with ink, the ink is transferred to the pinch roller 22, and the ink is transferred again to the recording sheet material 4. This is because the material 4 may be contaminated. That is, in the state shown in FIG. 12B, the recording sheet material 4 is in a standby state until the ink is dried.

  The reason why the recording sheet material 4 is not in the position shown in FIG. 12 (a), but the paper feed roller 21 is rotated in the reverse direction to be fed back to the position in FIG. This is largely due to deformation of the sheet material 4. That is, when recording is performed on the recording sheet material 4 by a wet ink jet recording method, the fibers constituting the sheet material expand because the recording sheet material 4 absorbs moisture, and the recording sheet material 4 May grow. Depending on the pattern to be recorded, there may be a mixture of a portion that extends and a portion that does not extend in the recording sheet material 4, and in such a case, concavity and convexity are particularly noticeably formed. The size of the unevenness mainly depends on the time after the recording sheet material starts to absorb moisture, and the unevenness increases with time, and converges to a predetermined deformation amount. If the amount of deformation at the end of the recording sheet material 4 increases after a long time, the end pinches when the recording sheet material enters the nip portion even if the pinch roller 22 is moved away from the paper feed roller 21. There is a possibility of jamming due to interference with the roller 22. In order to prevent this, after the recording is finished, the recording sheet material 4 is moved back to below the pinch roller 22 by back feeding before the deformation of the unevenness of the recording sheet material 4 becomes large. . For the above reasons, the recording sheet material 4 is back-feeded to the position shown in FIG. 12B, and the recording portion of the recording sheet material 4 is waited for the ink to dry. The gap between the paper feed roller 21 and the pinch roller 22 in the separated state (release state) is usually that of the recording sheet material 4 after recording on the first surface (front surface) of the recording sheet material 4. It is set to be larger than the deformation amount.

  FIG. 12C shows a state in which the recording sheet material 4 is conveyed (reverse direction conveyance) toward the automatic duplex unit 2 that is the sheet material reversing unit. When the recorded portion of the recording sheet material 4 is dried and no ink is transferred even when pressed against the pinch roller 22, the lift mechanism is moved to the fourth position as shown in FIG. The sheet material 4 is sandwiched between the pinch roller 22 and the paper feed roller 21. In this state, the paper feed roller 21 is driven in the reverse direction to back feed the recording sheet material 4. At this time, the PE sensor lever 66 is rotated and locked upward, so that the leading end of the PE sensor lever 66 does not bite into the recording sheet material 4 and does not rub off the recorded portion. Further, since the sheet passing guide 70 is in a lowered state, the sheet passing surface is substantially horizontal, and the recording sheet material 4 can be conveyed straight toward the automatic duplex unit 2. In the present embodiment, the sheet passing guide 70 is in the raised state in the normal state, but the present invention is not limited to this, and the normal state of the sheet passing guide 70 may be the lowered state. That is, it is possible to configure the normal standby state as the third position or the fourth position of the lift mechanism so as to move to the first position during the paper feeding operation from the main ASF 37. If comprised in this way, when inserting the recording sheet material 4 with a rigid rigidity from the paper discharge roller side, it will become possible to insert smoothly.

  A supplementary description will be given of the time required to dry the ink, which affects the stop time (drying waiting time) in the state shown in FIG. Whether there is a possibility that the ink may be transferred to the pinch roller 22, in other words, whether the ink applied to the recording sheet 4 is dry depends on a number of conditions. That is, the type of recording sheet material 4, the type of ink used, the method of overprinting the used ink, the amount of ink used per unit area (for example, the density per unit area of recorded data), and the recording operation are performed. The conditions include the temperature of the environment, the humidity of the environment in which the recording operation is performed, and the flow velocity of the gas in the environment of the recording operation. Roughly speaking, if the recording sheet material 4 that has an ink receiving layer on the surface and can quickly guide the ink to the inside is used, the ink is easily dried quickly. Also, if an ink mainly composed of a dye or the like, which has small ink particles and easily penetrates into the recording sheet material, is easily dried quickly. Further, if ink that reacts chemically is used and solidified by being overlaid on the surface of the recording sheet material, it is easy to dry quickly. Also, if the amount of ink applied per unit area is reduced, it is easy to dry quickly. Also, if the temperature of the environment in which the recording operation is performed is increased, it is easy to dry quickly. Also, if the humidity of the environment in which the recording operation is performed is lowered, it is easy to dry quickly. Also, if the flow velocity of the gas in the environment where the recording operation is performed is increased, it is easy to dry quickly. As described above, since the necessary drying time is determined depending on several conditions, in the present embodiment, a general use condition (a general recording sheet material and a general recording sheet) is used by using a predetermined ink system. A recording time is recorded as a standard value, and the drying time is changed according to a predictable condition.

  This predictable condition is the amount of ink deposited per unit area. In addition, if the environmental temperature detection means, environmental humidity detection means, environmental wind speed detection means, etc. are used in combination, the drying standby time can be further reduced. It is also possible to predict. For example, the data received from the host device 308 shown in FIG. 21 is stored on the RAM 312, the amount of ink hit per unit area is calculated, and the maximum value is compared with a predetermined threshold value recorded in the ROM 311. The drying waiting time can be determined. That is, when the maximum value of the amount of ink deposited per unit area is large, the drying standby time is lengthened. Conversely, when the maximum value is small, the drying standby time is shortened to optimize the drying standby time according to the recording pattern. be able to.

  Also, the drying standby time differs depending on whether the type of ink used for recording is dye-based ink or pigment-based ink, but in the case of dye-based ink, the drying standby time is shortened because it is easy to dry. In the case of pigment-based ink, since it is difficult to dry, the drying waiting time is lengthened. Also, when the ambient temperature is high, the drying is easy, so the drying standby time is shortened. When the ambient temperature is low, the drying is difficult, so the drying standby time is lengthened. Further, since the drying is difficult when the ambient humidity is high, the drying standby time is lengthened, and when the ambient humidity is low, the drying is easily performed, so the drying standby time is shortened. Also, in the case of a recording sheet material that has an ink receiving layer on the surface and takes in the ink that has been ejected into the sheet material immediately, the surface of the recording sheet material is easy to dry, so the drying waiting time is shortened. However, in the case of a recording sheet material with strong water repellency, it is difficult to dry, so the drying standby time is lengthened.

<Inversion operation>
As shown in FIG. 2, in the double-sided unit 2, the recording sheet material 4 is sandwiched between the second double-sided roller 109 and the second double-sided pinch roller 113 to change the traveling direction, and further, the first double-sided roller 2 It is sandwiched between the roller 108 and the first double-sided pinch roller 112 and conveyed in the direction of arrow d in FIG. 2, and finally returns to the horizontal sheet material path by changing the traveling direction by 180 degrees. In this way, the recording sheet material 4 after the recording on the front side surface is reversed by the horizontal path below the main ASF 37 and the sheet material reversing unit 2 behind the main ASF 37, It is transported again to the recording unit, and the back side surface can be recorded.

  13 and 14 are schematic side sectional views showing the sheet material path and the conveying roller of the automatic duplex unit 2 which is the sheet material reversing unit. As shown in FIGS. 13 and 14, inside the sheet material reversing unit 2, the structure of the sheet material reversing unit (automatic duplex unit) 2 and the sheet material reversing unit frame (both sides) constituting a part of the sheet material conveyance path are provided. Unit frame) 101, an inner guide 102 which is fixed inside the double-sided unit frame 101 and forms a part of the sheet material conveyance path, and a part of the sheet material conveyance path which is arranged to be openable and closable behind the double-sided unit frame 101. A rear cover 103, a switching flap (movable flap) 104 biased in a predetermined direction by a switching flap spring 105, an outlet flap 106 biased in a predetermined direction by an outlet flap spring 107, and a rubber portion. A first reverse roller (double-sided roller) 108 including a first double-sided roller rubber 110 and a second double-sided roller which is a rubber part. Second reversing section rollers (sided roller) 109 that includes a rubber 111 is provided.

  When the paper feeding roller 21 is rotated in the reverse direction from the state shown in FIG. 12C and the recording sheet material 4 is conveyed to the sheet material reversing unit 2, the exit flap 106 is urged by the exit flap spring 107. As shown in FIG. 13, the introduction path is limited to one direction. For this reason, the recording sheet material 4 proceeds in the direction of arrow a in FIG. Then, the recording sheet material 4 hits the switching flap 104 which is a movable flap. In the case of the recording sheet material 4 capable of normal double-sided recording, the load of the switching flap spring 105 is set so that the switching flap 104 does not rotate, and the recording sheet material 4 has the switching flap 104 and the duplex unit frame. Proceed along the path to 101. As is, the recording sheet 4 has a recorded surface (front surface) in contact with the second double-sided roller rubber 111 of the second double-sided roller 109 and a non-recorded surface (back surface) having a high lubricity. In a state where the second double-sided pinch roller 113 made in this manner is in contact with each other, it is sandwiched between them.

  At this time, the peripheral speeds of the first double-sided roller 108, the second double-sided roller 109, and the paper feed roller 21 are set to be approximately the same by a driving mechanism described later, so The roller 109 is conveyed without slipping. Further, since the peripheral speeds are substantially the same, the recording sheet material 4 is not slackened or tensioned. When the traveling direction is changed by the second double-sided roller 109, the recording sheet material 4 travels along the rear cover 103. Similarly, the first double-sided roller rubber 110 of the first double-sided roller 108 and the first double-sided pinch roller. 112.

  The recording sheet material 4 is changed in the traveling direction again by the first double-sided roller 108 and is conveyed in the direction of arrow b in FIG. The first and second double-sided rollers 108 and 109 constitute reversing rollers for reversing the front and back of the recording sheet material 4 and the conveying direction. When the recording sheet material 4 advances as it is, the leading end of the recording sheet material 4 comes into contact with the outlet flap 106. Since the exit flap 106 is urged by the exit flap spring 107 with a very weak load, the recording sheet 4 itself pushes the exit flap 106 and exits the automatic duplex unit 2. When the leading end of the recording sheet material 4 exits the exit flap 106, the trailing end of the recording sheet material 4 already passes under the exit flap 106 so that the sheet material in the automatic duplex unit 2 can be used. Since the length of the path is set, the front end portion and the rear end portion of the recording sheet material 4 itself do not rub against each other.

  Although details will be described later, the length of the recording sheet material 4 can be measured by the PE sensor lever 66 when recording on the front side surface of the recording sheet material 4. The recording sheet material 4 shorter than the distance to the second double-sided roller 109 or the distance from the first double-sided roller 108 to the paper feed roller 21 and one round from the exit flap 106 of the sheet material reversing unit (automatic duplexing unit) 2 When the recording sheet material 4 longer than the distance to return to the exit flap 106 is inserted, a warning is issued when the recording on the front side is finished, and the recording sheet material 4 is sent to the automatic duplex unit 2. The paper is discharged without being conveyed (reversely conveyed).

  Here, the reason why the recording sheet material 4 is conveyed with the recorded surface of the recording sheet material 4 directed toward the first double-sided roller rubber 110 and the second double-sided roller rubber 111 will be described. Since the first double-sided roller rubber 110 and the second double-sided roller rubber 111 are on the driving side, and the first double-sided pinch roller 112 and the second double-sided pinch roller 113 are on the driven side, the recording sheet material 4 is the driving side roller. The driven side is rotated by the frictional force with the recording sheet material 4. At this time, the axial loss of the rotary shaft supporting the first double-sided pinch roller 112 and the second double-sided pinch roller 113 should be sufficiently small. If the axial loss increases for some reason, the recording sheet material 4 and There is a possibility that slip occurs between the first double-sided pinch roller 112 and the second double-sided pinch roller 113. The portion recorded on the recording sheet material 4 is dried to the extent that the ink does not transfer due to contact with the roller. However, when it is rubbed relatively strongly, the ink is removed from the surface of the recording sheet material 4. There is also a possibility of peeling. If the recorded surface of the recording sheet material 4 is in contact with the first double-sided pinch roller 112 or the second double-sided pinch roller 113 and slips between these rollers, the recording material 4 is rubbed strongly. The ink on the used surface may be peeled off. In order to prevent this, in the present embodiment, the driving side member is disposed so as to abut on the recorded surface (front side surface), and the driven member is abutted against the unrecorded surface (back side surface).

  Furthermore, the following reasons can be given for such an arrangement. That is, the first double-sided roller 108 or the second double-sided roller 109 on the driving side is restricted by the bending radius of the recording sheet material 4 and thus has a certain large diameter. The diameter of the 112 and the second double-sided pinch roller 113 can be reduced. Therefore, in order to design the automatic duplex unit 2 compactly, the first double-sided pinch roller 112 and the second double-sided pinch roller 113 are often designed to have a small diameter. Basically, ink is not transferred from the recorded surface of the recording sheet material 4 to the roller side, but only a small amount is transferred, and the roller in contact with the recorded surface is gradually soiled with ink. is there. In the case of a roller having a reduced diameter, the outer periphery of the roller comes into contact with the recording sheet material 4 more frequently, and therefore, the speed at which the roller is soiled becomes faster than that of a large-diameter roller. It can be said that. For the reasons described above, in the present embodiment, from the viewpoints of downsizing of the apparatus and contamination of the rollers, the first both surfaces having a large diameter on the side in contact with the recorded surface (front surface) of the recording sheet 4 The roller 108 and the second double-sided roller 109 are placed.

  Furthermore, there are other reasons for such an arrangement as follows. That is, when the sheet material is nipped and conveyed by a pair of rollers driven on one side, the driving side is made of a material with a high friction coefficient and the driven side is made of a material with a low friction coefficient in order to make the conveyance amount accurate. In order to increase the area of the nip part (nip area), one of them is often made of an elastic material. Usually, a rubber material (rubber-like elastic material) that has a high friction coefficient at a relatively low cost and is rich in elasticity is usually used as the material of the driving roller. Further, in order to increase the conveying force, a method of rough polishing the surface of rubbers including an elastomer or the like and intentionally attaching minute irregularities is often used. In this case, the driven side is generally made of a polymer resin having a relatively small surface friction coefficient. When comparing rubbers with minute irregularities with the surface of a smooth polymer resin, both ink stains adhere to the recorded surface of the recording sheet material 4, but the minute irregularities In rubbers with a mark, dirt is held by the unevenness, so that the dirt is rarely re-transferred to the recording sheet material 4, whereas the smooth polymer resin peels off the dirt and becomes a recording sheet material 4. Since retransfer is often performed, it can be said that it is advantageous to bring rubbers into contact with the recorded surface of the recording sheet 4. For the above reasons, in this embodiment, a roller made of a rubber material is disposed on the side of the recording sheet material 4 that contacts the recorded surface (front surface) and contacts the non-recorded surface (back surface). A polymer resin roller is arranged on the side.

<Processing of highly rigid recording sheet material>
Next, the operation when recording is performed on a recording sheet having high rigidity using the automatic duplex unit (sheet material reversing unit) 2 described above will be described. The highly rigid recording sheet material may be, for example, a case where a thick sheet having a thickness of about 2 mm to 3 mm or a disc-like or irregularly shaped recording sheet material is conveyed while being placed on a predetermined tray. Since such a recording sheet material has high rigidity, it cannot be curved to follow the diameter of the double-sided roller of the sheet material reversing unit 2, and automatic double-sided recording cannot be performed. However, it is possible to perform recording on one side of such a highly rigid recording sheet material with the sheet material reversing unit 2 mounted on the recording apparatus.

  When the recording sheet material 4 has a high rigidity, the main ASF 37 cannot be used to feed the sheet. In this case, in order to use a straight sheet material path, the paper feed roller 21 from the discharge roller side is used. The recording sheet material 4 is fed toward the side. The operation of the automatic duplex unit (sheet material reversing unit) 2 at that time will be described below.

  FIG. 14 is a schematic side sectional view for explaining the operation of the switching flap 104. FIG. 14A shows a state in which automatic duplex recording is performed using the above-described normal recording sheet material 4. In this state, since the switching flap spring 105 continues to urge the switching flap 104 against the stopper against the pressing force of the recording sheet material 4, the recording sheet material 4 is guided (guided) to the reversing sheet material path. )

  FIG. 14B shows a state in which the recording sheet material 4 having high rigidity is used. When the recording sheet 4 having high rigidity is conveyed to the automatic duplex unit 2, the recording sheet 4 passes under the exit flap 106 and abuts on the switching flap 104. Since the switching flap spring 105 is set to have a spring load that allows the switching flap 104 to be retracted by the pressing force when the recording sheet material 4 with high rigidity is inserted and the switching flap 104 is pressed, the switching flap spring 105 has high rigidity. As the sheet material 4 progresses, it swings in the counterclockwise direction (the arrow direction in FIG. 14B) and retracts. Therefore, the recording sheet material 4 having high rigidity is guided to a retreat path 131 that is a second sheet material path provided between the first double-sided roller 108 and the second double-sided roller 109. Since a hole (also referred to as “through hole” or “opening”) is formed in a portion corresponding to the retreat path 131 of the rear cover 103, even when a long and highly rigid recording sheet material 4 is used, The sheet material reversing unit (automatic duplex unit) 2 does not interfere with the conveyance.

  The gist of the present invention is not limited to the above-described configuration shown in FIG. That is, in the practice of the present invention, it is not essential to provide the retreat path 131 between the upper and lower two-sided rollers 108 and 109. For example, a configuration as described below can be employed. FIG. 22 is a schematic side cross-sectional view showing a sheet material reversing unit (automatic duplex unit) configured by disposing a large-diameter reversing unit roller (double-sided roller) above a substantially horizontal sheet material path. In FIG. 22, the switching flap 104 is urged by a switching flap spring (not shown), and the spring force (pressing force) of the switching flap spring is changed when the recording sheet material 4 having high rigidity comes into contact. The load is set so that 104 can rotate. Also in FIG. 22, portions corresponding to the respective portions in FIG. 13 and FIG. 14 are denoted by the same reference numerals, and details thereof will be referred to the above description, and detailed description thereof will be omitted here.

  Therefore, in the case of the recording sheet material 4 with low rigidity, the recording sheet material 4 advances in the direction of arrow a in FIG. 22 by the rotation of the first reverse roller (double-sided roller) 108 in the direction of arrow c in FIG. However, in the case of the recording sheet material 4 having high rigidity, the switching flap 104 is pushed away, and the retreat path 131 in the direction of arrow b in FIG. As a result, even when a long and highly rigid recording sheet material 4 is used, the sheet material reversing unit (automatic duplex unit) 2 is not interfered and the conveyance is not limited. As described above, the automatic duplex unit 2 of the present embodiment has two sheet material paths, and includes the recording sheet material 4 that is rigid and cannot be bent without removing the automatic duplex unit 2). It is also possible to perform single-sided recording.

<Drive mechanism of automatic duplex unit>
Next, the driving mechanism of the rollers of the automatic duplex unit 2 as the sheet material reversing unit will be described. FIG. 15 is a schematic cross-sectional side view showing the configuration of a driving mechanism for rollers of the automatic duplex unit 2 when one embodiment (see FIG. 1) of the recording apparatus to which the present invention is applied is viewed from the side opposite to FIG. FIG. FIG. 16 is a schematic sectional side view for explaining the operation of the driving mechanism for the rollers of the automatic duplex unit 2. Explaining this drive mechanism, the power from the LF motor 26 is transmitted to the double-sided sun gear 116 via the double-sided transmission gear train 115. A first double-sided planetary gear 118 and a second double-sided planetary gear 119 are rotatably attached to a swing arm (double-sided pendulum arm) 117 that can swing around the double-sided sun gear 116 as a center of rotation. 116 is engaged. A double-sided pendulum arm spring 132 is attached to the double-sided pendulum arm 117.

  The first reverse delay gear 121 can be engaged with the second double-sided planetary gear 119, and the first reverse delay gear 121 and the second reverse delay gear 122 provided coaxially therewith include a reverse delay gear. A relative biasing force is applied by the spring 123. The first double-sided roller gear 125 fixed to the first double-sided roller (reversing unit roller) 108 and the second double-sided roller gear 126 fixed to the second double-sided roller (reversing unit roller) 109 are double-sided rollers. They are connected by idler gear 124. A spiral groove gear 120 is engaged with the double-sided sun gear 116 via an idler gear. A stop arm 127 that engages and swings in the groove of the spiral groove gear 120 is centered by a stop arm spring 128.

  As described above, in this embodiment, the driving force of the automatic duplex unit 2 that is the sheet material reversing unit is obtained from the LF motor 26 that drives the paper feed roller 21. With this configuration, the sheet feeding roller 21 and the first reversing unit roller (double-sided roller) 108 or the second reversing unit roller (double-sided roller) 109 cooperate to convey the recording sheet material 4. In this case, the timing of starting and stopping can be almost completely synchronized so that the recording sheet material conveyance speed can be made substantially the same. Therefore, it is preferable to adopt such a configuration.

  An appropriate frictional force is applied between the double-sided sun gear 116 and the double-sided pendulum arm 117, and the double-sided pendulum arm 117 swings according to the rotational direction of the double-sided sun gear 116. Here, the direction in which the paper feed roller 21 rotates the LF motor 26 in the direction in which the recording sheet material 4 is conveyed in the paper discharge direction is the forward direction, and the direction in which the recording sheet material is conveyed to the automatic duplex unit 2 side. Assuming that the direction of rotating 26 is the reverse direction, when the LF motor 26 rotates in the forward direction, the double-sided sun gear 116 rotates in the direction of arrow a in FIG. As the double-sided sun gear 116 rotates, the double-sided pendulum arm 117 also swings in the direction of arrow a in FIG. Then, the first double-sided planetary gear 118 engages with the double-sided roller idler gear 124 and rotates the double-sided roller idler gear 124. As the double-sided roller idler gear 124 rotates, the first double-sided roller gear 125 rotates in the direction of arrow c in FIG. 15, and the second double-sided roller gear 126 similarly rotates in the direction of arrow d in FIG. The arrow c direction and the arrow d direction in FIG. 15 are directions in which the first double-sided roller 108 and the second double-sided roller 109 respectively convey the recording sheet material 4 in the sheet material reversing unit (automatic double-sided unit) 2. .

  When the LF motor 26 rotates in the reverse direction, the double-sided sun gear 116 rotates in the direction of arrow b in FIG. As the double-sided sun gear 116 rotates, the double-sided pendulum arm 117 basically swings in the direction of arrow b in FIG. Then, the second double-sided planetary gear 119 is engaged with the first reverse delay gear 121. The first inversion delay gear 121 and the second inversion delay gear 122 have protrusions protruding from the opposing thrust surfaces, and when the second inversion delay gear 122 is considered fixed, the first inversion delay gear 122 When 121 is rotated once, it plays the role of clutch means in which the protrusions mesh with each other.

  Before the second double-sided planetary gear 119 is engaged with the first reverse delay gear 121, the reverse delay gear spring 123 described above is provided between the first reverse delay gear 121 and the second reverse delay gear 122. The protrusions are biased in directions away from each other, and after the first reverse delay gear 121 has started to rotate, the second reverse delay gear 122 starts to rotate after almost one rotation. Thus, the first double-sided roller 108 and the second double-sided roller 109 stop during the period from when the LF motor 26 starts to rotate in the reverse direction to when the second reverse delay gear 122 starts to rotate. This is the delay period.

  When the second reverse delay gear 122 is rotated, the first double-sided roller gear is rotated in the direction of arrow c in FIG. 15 and the second double-sided roller gear is rotated in the direction of arrow d in FIG. 15 via the double-sided roller idler gear 124. . This is the same direction as the rotation direction when the LF motor 26 is rotated in the forward direction. With such a mechanism, the first double-sided roller 108 and the second double-sided roller 109 can always be rotated in the direction in which the recording sheet material 4 is conveyed, regardless of the rotation direction of the LF motor 26.

  Here, the operation of the spiral groove gear 120 will be described. The spiral groove gear 120 has a gear surface formed on the outer periphery thereof, and a cam having a spiral groove cut with an endless track on the innermost periphery and the outermost periphery formed on one end surface. In this embodiment, the spiral groove gear 120 is connected to the double-sided sun gear 116 via an idler gear, and thus rotates in synchronization with the double-sided sun gear 116 in the same direction. Since the follower pin 127a which is a part of the stop arm 127 is engaged with the groove of the spiral groove gear 120, the stop arm 127 swings as the spiral groove gear 120 rotates. For example, when the spiral groove gear 120 rotates in the direction of arrow e in FIG. 15, the follower pin 127a is drawn into the inner periphery, so that the stop arm 127 swings in the direction of arrow g in FIG. Even if the spiral groove gear 120 continues to rotate in the direction of arrow e in FIG. 15, the follower pin 127a enters the endless track of the innermost circumference, so that the stop arm 127 stops at a predetermined position.

  Conversely, when the spiral groove gear 120 rotates in the direction of arrow f in FIG. 15, the follower pin 127a moves toward the outer periphery, so that the stop arm 127 swings in the direction of arrow h in FIG. Similarly, when the spiral groove gear 120 continues to rotate in the direction of the arrow f in FIG. 15, the follower pin 127a enters the outermost endless track, and the stop arm 127 stops at a predetermined position. Note that when the rotational direction of the spiral groove gear 120 changes, the stop arm spring 128 moves the stop arm 127 to the center of its moving range so that it can smoothly move from the outermost track and the innermost track to the spiral groove. Centering around the center.

  As shown in FIG. 16, the stop arm 127 performing such an operation acts on a double-sided pendulum arm spring (swinging arm spring) 132 attached to a double-sided pendulum arm (swinging arm) 117. The double-sided pendulum arm spring 132 is an elastic member that is attached to the double-sided pendulum arm 117 and extends in the direction of the stop arm 127. Further, the tip of the double-sided pendulum arm spring 132 is always located in the center direction of the spiral groove gear 120 with respect to the stop arm 127.

  With such a positional relationship, the following action is given when the LF motor 26 rotates in the forward direction. That is, when the LF motor 26 rotates in the reverse direction to convey the recording sheet material 4 to the sheet material reversing unit 2 and is reversed upside down, the recording sheet material 4 returns to the paper feed roller 21 as shown in FIG. As shown in c), the stop arm 127 is engaged with the outermost endless track of the spiral groove gear 120. Thereafter, when the LF motor 26 is rotated in the forward direction to record the back side surface, the stop arm 127 moves toward the inner periphery of the spiral groove gear 120. When the LF motor 26 rotates in the forward direction, the swing arm 117 swings in the direction of arrow a in FIG. 15 to transmit power, so that the stop arm 127 is shown in FIG. 16 (d). Is in contact with the double-sided pendulum arm spring 132 on the way to the inner circumference.

  When the LF motor 26 further rotates in the forward direction, the stop arm 127 further moves to the inner periphery and elastically deforms the double-sided pendulum arm spring 132. Therefore, the double-sided pendulum arm 117 includes the first double-sided planetary gear 118 and the double-sided roller idler. The double-sided force balances between the force acting in the pressure angle direction when the tooth surfaces of the gear 124 mesh with each other, the force that swings the double-sided pendulum arm 117 in the direction of arrow a in FIG. The posture of the pendulum arm 117 is determined. In the case of this embodiment, since the repulsive force of the double-sided pendulum arm spring 132 is set small, even if the stop arm 127 is in a position where it enters the innermost endless track as shown in FIG. By simply elastically deforming the double-sided pendulum arm spring 132, power transmission between the first double-sided planetary gear 118 and the double-sided roller idler gear 124 is continued.

  When the LF motor 26 is intermittently driven and repeatedly rotated and stopped, the tooth surfaces of the first double-sided planetary gear 118 and the double-sided roller idler gear 124 remain overlapped even in the stopped state. There is no disengagement. However, when the recording on the back side of the recording sheet material 4 is completed and the drive transmission to the automatic duplex unit 2 becomes unnecessary, it is preferable to cut the drive in order to reduce the load on the LF motor 26. . Therefore, the following method is performed when it is desired to cut off the drive transmission.

  That is, while the stop arm 127 is in the innermost endless track and the double-sided pendulum arm spring 132 is elastically deformed, the LF motor 26 is slightly rotated in the reverse direction as shown in FIG. Let Due to the repulsive force of the double-sided pendulum arm spring 132, the double-sided pendulum arm 117 stops moving in the direction of arrow b in FIG. 15 by overlapping the tooth surfaces of the first double-sided planetary gear 118 and the double-sided roller idler gear 124. Since the rotation in the direction to remove the overlapping of the tooth surfaces is given from the state, the double-sided pendulum arm 117 is rotated in the direction of arrow b in FIG. Once the double-sided pendulum arm 117 is rotated in the direction of arrow b in FIG. 15, the double-sided pendulum arm spring 132 that has been elastically deformed returns to its original shape, so that even if the LF motor 26 is rotated in the forward direction, the double-sided pendulum arm Since the arm spring 132 and the stop arm 127 interfere with each other, the double-sided pendulum arm 117 cannot swing to a position where the first double-sided planetary gear 118 and the double-sided roller idler gear 124 mesh with each other. Therefore, from this state, the driving force is not transmitted to the side of the double-sided pendulum arm 117 in the automatic double-sided unit 2 unless the LF motor 26 is rotated in the reverse direction by a predetermined amount. Since the drive to the double-sided pendulum arm 117 merely rotates the gear train, the load applied to the LF motor 26 is very small, and there is almost no difference from the load when the automatic double-side unit 2 is not attached.

  If the LF motor 26 rotates in the reverse direction from the state where the stop arm 127 is in the innermost endless track, there is no effect between the double-sided pendulum arm spring 132 and the stop arm 127. As described above, the drive can be transmitted to the first reverse delay gear 121.

  As is clear from the above description, according to the configuration of FIGS. 15 and 16, the paper feeding roller 21, the recording unit N, and the sheet material reversing unit 2 are provided. After recording on the surface (front side), the recording sheet material 4 is conveyed to the sheet material reversing portion by the paper feed roller, and the recording sheet material after the reversal is sandwiched again by the paper feed roller. In the double-sided recording apparatus for recording on the second surface (back surface) of the material, after recording on the first surface, the leading edge of the recording sheet material is moved to the sheet material reversing portion after the drive of the paper feed roller is started. The reversing unit roller is configured to start synchronous rotation with the paper feed rollers 108 and 109 before being sandwiched by the reversing unit roller 109. Further, the recording sheet material 4 is reversed by the first clutch means connected by rotating the paper feed roller 21 by a predetermined amount in the first rotation direction (reverse rotation) for conveying the recording sheet material 4 to the sheet material reversing unit 2. The part rollers 108 and 109 are configured to start synchronous rotation with the paper feed roller 21.

[Double-sided recording method]
Next, details of the operation of automatic duplex recording according to the present embodiment, including the operation of the driving mechanism of the rollers of the automatic duplex unit 2 described above, will be described with reference to the flowchart of FIG.

  When the automatic double-sided recording is started, the recording sheet material 4 is fed in step S1, and the recording sheet material 4 is supplied from the main ASF 37 or the like toward the paper feed roller 21, for example. Next, in step S2, the front side surface is recorded. This is the same operation as in the case of recording on only one side. The state of the roller driving mechanism at this time is the state shown in FIG. In other words, after the drive mechanism of the automatic duplex unit 2 is initialized, the LF motor 26 is rotating in the forward direction, and the front side surface is being recorded during automatic duplex recording, or automatic duplex recording is not used. It is in a state such as during recording operation. In this state, the follower pin 127a of the stop arm 127 is on the innermost endless track of the spiral groove gear 120, and the double-sided pendulum arm (swinging arm) 117 tries to swing in the direction of arrow a in FIGS. The double-sided pendulum arm 117 is driven from the LF motor 26 because the arm spring 132 is in contact with the stop arm 127 and cannot be rotated any further, and the first double-sided planetary gear 118 cannot be engaged with the double-sided roller idler gear 124. The force is not transmitted to the first double-sided roller gear 125 and the second double-sided roller gear 126. In this state, the first double-sided roller 108 or the second double-sided roller 109 that has undergone axial loss due to the pressure of the first double-sided pinch roller 112 or the second double-sided pinch roller 113 does not rotate, so that LF The load received by the motor 26 is small.

  Next, in step S3, it is confirmed whether or not the rear end of the recording sheet material 4 has been detected by the PE sensor 67 when the front surface recording is completed. That is, if the PE sensor 67 detects the recording sheet material 4 at this time, the rear end of the surface of the recording sheet material 4 has not yet reached, so in step S4, the LF motor 26 is rotated in the forward direction. Then, the rear end of the front surface of the recording sheet material 4 is moved to the position p2 which is slightly further after passing through the PE sensor lever 66. Next, in step S5, the length of the recording sheet material 4 is determined based on the amount of the recording sheet material 4 conveyed from when the PE sensor 67 detects the front end of the recording sheet material 4 until the trailing edge of the surface is detected. Calculate the length. As described above, when the length of the recording sheet material 4 is shorter than the predetermined length L1, the conveyance from the paper feed roller 21 to the second double-sided roller 109 or from the first double-sided roller 108 to the paper feed roller 21 is performed. Since it will not reach the roller in the meantime, it is necessary to exclude it from the automatic duplex recording operation. When the length of the recording sheet material 4 is longer than the predetermined length L2, the recorded surfaces of the recording sheet material 4 are interlaced in the sheet material path from the paper feed roller 21 to the automatic duplex unit 2. Therefore, it is necessary to exclude it from the automatic duplex recording operation. If it is determined that the automatic duplex recording operation is excluded under this condition, the process proceeds to step S6, where the LF motor 26 is rotated in the forward direction, and the recording sheet material 4 is discharged as it is. If the condition is met, the process proceeds to step S7, where the lift mechanism is set to the third position as shown in FIG. 10C, and the pinch roller 22 is released (released).

  Next, in step S8, it is confirmed whether the rear end of the front side surface of the recording sheet material 4 has already been conveyed to the downstream side from the position p1 in the vicinity of the pinch roller 22. If the sheet has already been fed to the downstream side, the back end of the surface is p1 in step S9 so that the pinch roller 22 is securely held between the paper feed roller 21 and the pinch roller 22 when the pinch roller 22 is returned to the pressure contact state. LF motor 26 is rotated in the reverse direction until it comes to back feed. The state of the roller driving mechanism at this time is the state shown in FIG. It should be noted that, from step S2 to step S8, it is desirable to perform step S9 before the recording sheet material 4 is deformed, as described above, so that the operation is not stopped as much as possible. On the other hand, if the rear end of the front surface is on the upstream side from p1, the recording sheet material 4 can be securely held by pressing the pinch roller 22 as it is, so the process proceeds directly to step S10.

  FIG. 16B shows a state immediately after the LF motor 26 starts rotating in the reverse direction. That is, immediately after the back-side feed is started after the recording of the front side surface (the state shown in FIG. 12B), or when the LF motor 26 is reversed to adjust the cue amount after feeding from the main ASF 37. It is a state. At this time, there is nothing that prevents the double-sided pendulum arm 117 from swinging in the direction of arrow b in FIGS. 15 and 16, so the second double-sided planetary gear 119 becomes the first reverse delay gear 121. Engage. Accordingly, the first inversion delay gear 121 starts to rotate, but the driving force is not transmitted to the second inversion delay gear 122 until the first inversion delay gear 121 rotates almost once, so the double-sided roller idler gear 124 does not rotate, The first duplex roller 108 and the second duplex roller 109 do not operate. Accordingly, even in this state, the load that the LF motor 26 receives is still small. This state is set because there is a distance from the paper feed roller 21 to the second double-side roller 109 when the recording sheet material 4 is back-fed in the automatic double-side recording operation. This is because the second double-sided roller 109 does not need to rotate until the leading edge of the material 4 reaches the second double-sided roller 109. In addition, as described above, the first double-sided roller 108 or the second double-sided roller 109 is not unnecessarily rotated when adjusting the cue amount during normal recording.

  In step S10, the process waits until the recorded ink on the front surface of the recording sheet 4 is dried. Since the necessary drying time varies depending on several factors as described above, the drying standby time t1 can be a variable parameter. Specifically, t1 is determined in consideration of conditions such as the type of recording sheet material 4, the type of ink, the method of overprinting ink, the amount of ink deposited per unit area, environmental temperature, environmental humidity, and environmental wind speed. To do.

  Next, in step S11, the lift mechanism is set to the fourth position as shown in FIG. As a result, the paper feed roller 21 and the pinch roller 22 again sandwich the recording sheet material 4. In step S12, the process waits for the drying waiting time t2. This may not be used when the drying standby time t1 is performed in step S10, and it is possible to proceed to the next step with t2 = 0. For example, when the recording operation is not performed at the rear end portion of the recording sheet material 4 and there is a blank portion, the blank space portion is pinched immediately after t1 = 0 in step S10. There is no problem even if the roller 22 is controlled so as to be pressed, but if the sheet material 4 for recording is transported immediately as it is, the ink before drying may be transferred to the pinch roller 22. Therefore, in such a case, it is convenient to set the drying standby time t2 here.

  In step S13, the LF motor 26 is rotated in the reverse direction to back-feed the recording sheet material by a predetermined amount x1. In this step S13, the recording sheet material 4 is conveyed to the automatic duplex unit 2 and turned upside down. When this step S13 is completed, the leading end of the back side surface has returned to a position slightly ahead of the paper feed roller 21. The state of the driving mechanism of the rollers here is the state shown in FIG. 16C, which is a state in which the LF motor 26 is further rotated in the reverse direction. That is, the recording sheet material 4 is back-fed and reversed by the automatic duplex unit 2. When the reverse delay gear 121 rotates almost once from the state of FIG. 16B, the protrusion protruding in the thrust direction of the first reverse delay gear 121 is the protrusion of the second reverse delay gear 122 provided oppositely. And the first reverse delay gear 121 and the second reverse delay gear 122 start to rotate together. When the second reverse delay gear 122 starts rotating, since the second reverse delay gear 122 is always engaged with the double-sided roller idler gear 124, the double-sided roller idler gear 124, the first double-sided roller gear 125, and the second The double-sided roller gear 126 rotates. As a result, the first double-sided roller 108 rotates in the direction of arrow c in FIG. 15, and the second double-sided roller 109 rotates in the direction of arrow d in FIG.

  That is, in this embodiment, after recording on the first surface (front surface), the driving of the paper feed roller 21 is started, and then the leading end of the recording sheet material 4 is the reversing portion roller of the sheet material reversing portion 2. The reversing unit roller 109 is configured to start synchronous rotation with the paper feed roller 21 until it is nipped by 109. Further, in the above-described configuration, the connection is made by rotating the paper feed roller 21 by a predetermined amount in the first rotation direction (reverse rotation) in which the recording sheet material 4 is conveyed to the sheet material reversing unit 2. The reversing section roller 109 is configured to start synchronous rotation with the paper feed roller 21 by the clutch means (see FIGS. 15 and 16). And the structure containing the mechanism 120, 127, 132 which restrains the rocking | swiveling arm 117 holding the planetary gears 118, 119 is employ | adopted as a 1st clutch means.

  Next, a so-called registration operation when the front end of the back surface is sandwiched between the nip portions of the paper feed roller 21 and the pinch roller 22 will be described. First, in step S14, it is confirmed whether the recording sheet material 4 currently used is a thin sheet material with low rigidity or a thick sheet material with high rigidity, and the control is switched accordingly. The determination of the rigidity of the recording sheet material 4 may be made according to the type of the recording sheet material set by the user with a printer driver or the like, or may be determined using a detecting means for measuring the thickness of the recording sheet material. . Here, the reason why the control is divided into two is that the behavior when the recording sheet material 4 is bent to form a loop differs depending on the rigidity of the recording sheet material 4.

  First, the case of the thin recording sheet 4 having relatively low rigidity will be described. FIG. 18 is a schematic cross-sectional side view showing the registration operation of the tip of the back side surface when the thin recording sheet material 4 is used. By the reverse rotation of the LF motor 26 in step S13, the recording sheet material 4 is conveyed reversely as shown in FIG. At the end of step S13, the tip of the back side surface of the recording sheet material 4 has returned approximately to the vicinity of the sheet passing guide 70. In the case of the thin recording sheet material 4, the process proceeds to step S15. In step S15, the lift mechanism is operated to shift to the first position as shown in FIG. Thereby, the paper passing guide 70 is raised.

  FIG. 18B shows a state where step S15 has been completed. As described above, since the center of the pinch roller 22 is arranged slightly offset toward the first paper discharge roller 30 with respect to the center of the paper feed roller 21, the nip portion between the paper feed roller 21 and the pinch roller 22 is arranged. Is inclined at a slight angle with respect to the substantially horizontal line on which the recording sheet material 4 has been conveyed. By returning the sheet passing guide 70 to the raised position before the registration operation, the front end of the back surface of the recording sheet material 4 can be smoothly guided to the inclined nip portion. Next, in step S <b> 16, the LF motor 26 is rotated in the reverse direction, and the recording sheet material 4 is further conveyed toward the paper feed roller 21. Next, in step S <b> 17, the PE sensor 67 detects the tip of the back side surface of the recording sheet 4. If the tip of the back surface can be detected, the process proceeds to step S18.

  Next, in step S18, the recording sheet material 4 is conveyed by a distance x2 that is slightly longer than the distance to the paper feed roller 21 from the position where the leading edge of the back side surface is detected by the PE sensor 67. As a result, the leading end of the back side surface of the recording sheet material 4 reaches the nip portion between the paper feed roller 21 and the pinch roller 22, and the portion (length x 2) of the recording sheet material 4 that has been further transported is Flex to form a loop. FIG. 18C shows a state when step S18 is completed. The clearance in the height direction of the sheet material path is reduced by setting the sheet passing guide 70 to the raised position. However, since the recording sheet material 4 has relatively low rigidity, the loop is easily formed and bent ( Since the force for eliminating the loop) pushes the recording sheet material 4, the front end portion of the back side surface of the recording sheet material 4 follows the nip portion between the paper feed roller 21 and the pinch roller 22 that continues to reverse. Parallel to the feed roller 21. Thus, a so-called registration operation is completed. Next, in step S19, the rotation direction of the LF motor 26 is changed to the positive direction, the leading end of the back side surface of the recording sheet material 4 is sandwiched by the nip portion, and conveyed by a predetermined distance x3. Complete preparations to start recording.

  Next, the case of the thick recording sheet 4 having relatively high rigidity will be described. FIG. 19 is a schematic cross-sectional side view showing the registration operation of the front end of the back side surface when a thick recording sheet material is used. FIG. 19A shows a state in the middle of step S13 as in FIG. 18A, and FIG. 19B shows a state when step S13 is completed.

  In step S20, the LF motor 26 is rotated in the reverse direction while the sheet passing guide 70 is in the lowered position, and the recording sheet material 4 is moved from the front end of the back side surface of the recording sheet material 4 at the position stopped in step S13. A distance x4 slightly longer than the distance to the nip of the paper feed roller 21 is conveyed. As a result, as in the case of the thin recording sheet material 4, the tip of the back side surface of the recording sheet material 4 reaches the nip portion of the paper feed roller 21 that is reversed, and further the recording sheet material 4 Since the excessively conveyed portion (length x4) forms a loop, the tip of the back surface of the recording sheet 4 is parallel to the paper feed roller 21. Thus, the registration operation is completed. FIG. 19C shows a state when step S20 is completed.

  Next, in step S21, the rotation direction of the LF motor 26 is changed to the positive direction, the leading end of the back side surface of the recording sheet material 4 is sandwiched by the nip portion, and conveyed by a predetermined distance x3. Prepare to start recording. In step S19 or step S21, the LF motor 26, which has been rotating in the reverse direction until then, changes its rotational direction to forward rotation. At this time, the double-sided pendulum arm 117 swings in the direction of arrow a in FIGS. Then, the engagement between the second double-sided planetary gear 119 and the first reverse delay gear 121 is released. When the LF motor 26 rotates in the reverse direction, the first reverse delay gear 121 and the second reverse delay gear 122 are engaged with each other, but at the same time, a torsion coil spring sandwiched between the two. The reverse delay gear spring 123 is compressed. However, as described above, since the first reverse delay gear 121 becomes free (released), the reverse delay gear spring 123 expands by the spring force, so that the first reverse delay gear 121 is reversed approximately one turn, It returns to the initial state as shown in FIG.

  Next, in step S22, the lift mechanism is set to the first position as shown in FIG. 10A, and the preparation for starting the recording on the back surface is completed. Here, the reason why the sheet passing guide 70 is in the lowered position during the registration operation when the thick recording sheet 4 is used will be described.

  As in the case of the thin recording sheet material 4, when trying to form a loop as shown in FIG. 18C, if the recording sheet material 4 has a high rigidity, the recording sheet before reaching the nip portion. The material 4 is conveyed along the pinch roller holder 23. Therefore, even if the recording sheet material 4 is further conveyed after reaching the nip portion to try to form a loop, there is no space where the loop can be formed and the loop is not formed, so that the registration cannot be performed well. This is because there may be cases. If the loop is not formed, the recording sheet material 4 sandwiched between the first double-sided roller 108 and the paper feed roller 21 cannot be slackened. When a mechanism such as the double-sided pendulum arm 117 is used for the driving mechanism of the rollers as in the present embodiment, both sides of the LF motor 26 from the reverse rotation in step S20 to the normal rotation of the LF motor 26 in step S21 are used. It takes time for the pendulum arm 117 to swing, and during this period, the first double-sided roller 108 and the second double-sided roller 109 stop. Since the paper feed roller 21 is directly connected to the LF motor 26, there is no stop period, so that a deviation occurs in the sheet material conveyance speed. If there is a slack in the recording sheet material 4, the slack absorbs the deviation in the sheet material conveyance speed during step S21. However, when the recording sheet material 4 is not slack, the paper feed roller 21 and the like try to forcibly convey the recording sheet material without absorbing the deviation in the sheet material conveyance speed. Since the rear portion is sandwiched between the first double-sided rollers 108, it cannot actually be conveyed, the conveyance amount at the front end of the back side surface of the recording sheet material 4 is out of order, and the margin at the upper end of the back side surface is It may be shorter than the predetermined amount.

  Therefore, in the present embodiment, in order to solve the above-described problem, it is possible to form a loop by sufficiently taking a gap in the height direction between the sheet passing guide 70 and the pinch roller holder 23 as described above. Sufficient space is secured. Thereby, even when the thick recording sheet material 4 having relatively high rigidity is used, a good registration operation is possible.

  Next, in step S23, the recording of the back side surface of the recording sheet material 4 is performed. At this time, in most cases, the rear end portion of the back surface of the recording sheet 4 is still sandwiched between the first double-sided rollers 108. If the rotation of the first double-sided roller 108 is stopped as it is, a load for pulling the recording sheet material 4 backward is applied, which may deteriorate the sheet material conveyance accuracy. Accordingly, the first double-sided roller 108 is continuously driven while at least the rear end portion of the rear surface of the recording sheet 4 is sandwiched between the first double-sided rollers 108. At this time, the driving mechanism of the rollers is in a state as shown in FIG. FIG. 16D is a schematic sectional side view showing the operating state of the driving mechanism of the rollers of the automatic duplex unit 2 while the LF motor 26 is rotating in the forward direction after the reversing operation of the recording sheet material 4. FIG. That is, when the LF motor 26 rotates in the forward direction from the state of FIG. 16C, the double-sided pendulum arm 117 swings in the direction of arrow a in FIGS. At this time, the stop arm 127 is swung in the direction of arrow h in FIG. 15, and even if the double-sided pendulum arm 117 is swung in the direction of arrow a in FIG. 15, the double-sided pendulum arm spring 132 is in contact with the stop arm 127. Since the first double-sided planetary gear 118 is engaged with the double-sided roller idler gear 124, the driving force is transmitted.

  Thereafter, when the forward rotation of the LF motor 26 continues, the follower pin 127a is guided to the spiral groove gear 120 and moves toward the inner periphery, and the stop arm 127 swings in the direction of arrow g in FIGS. In the middle of swinging, the stop arm 127 contacts the double-sided pendulum arm spring 132 and deforms the double-sided pendulum arm spring 132. The reaction force caused by the deformation of the double-sided pendulum arm spring 132 causes a force to swing the double-sided pendulum arm 117 in the direction of the arrow b in FIGS. 15 and 16, but the first double-sided planetary gear 118 and the double-sided roller idler. While the driving force is being transmitted between the gears 124, the engagement between the first double-sided planetary gear 118 and the double-sided roller idler gear 124 is disengaged because the force with which the gear tooth surfaces engage is stronger. There is no drive and the drive continues. FIG. 16D shows this state.

  Further, as described above, even when intermittent driving with rotation and stop is performed, the tooth surfaces of the gears overlap each other, so that the first double-sided planetary gear 118 and the double-sided roller idler gear 124 are disengaged. There is no. Further, when the recording operation on the back side of the recording sheet material 4 is continued and the LF motor 26 is rotated in the forward direction, the follower pin 127a reaches the innermost peripheral portion of the spiral groove gear 120. The state of the double-sided roller driving mechanism at this time is as shown in FIG. At this time, the double-sided pendulum arm spring 132 is in a state of maximum displacement, but still the double-sided pendulum arm spring 132 has a force that causes the gear teeth surfaces to mesh with each other to be larger than the force that causes the double-sided pendulum arm 117 to swing. Since the load is set, the gears cannot be disengaged as long as the LF motor 26 continues to rotate in the forward direction. When the recording operation on the back side surface of the recording sheet material 4 is completed during the above process, the process proceeds to step S24.

  Next, in step S24, a discharge operation for discharging the recording sheet material 4 onto a discharge tray (not shown) is performed. In the paper discharge operation, the recording sheet material 4 is conveyed out of the recording unit main body 1 by the second paper discharge roller 31 by continuing the forward rotation of the LF motor 26.

  In step S25, the absolute position of the tip of the back side surface is confirmed. This is because the follower pin 127 a may not reach the innermost circumference of the spiral groove gear 120 when the short recording sheet material 4 is used. In this case, the follower pin 127a always reaches the innermost circumference of the spiral groove gear 120 when the recording operation on the back side of the recording sheet material 4 is completed by rotating the LF motor 26 by a predetermined length. I am doing so.

  In step S26, the driving mechanism of the rollers is initialized. As described above, since the force charged by the double-sided pendulum arm spring 132 is held by the engagement of the first double-sided planetary gear 118 and the double-sided roller idler gear 124, the LF motor 26 is slightly reversed in the reverse direction. Engagement is released simply by rotating. That is, when the LF motor 26 is rotated in the reverse direction, the double-sided pendulum arm 117 tends to swing in the direction of the arrow b in FIGS. 15 and 16, and therefore the first double-sided planetary gear 118 and the double-sided roller idler gear 124 are engaged. And the charged double-sided pendulum arm spring 132 swings in the direction of arrow b in FIGS. The driving mechanism of the rollers at this time is in the state shown in FIG.

  In the state of FIG. 16 (f), since the posture of the double-sided pendulum arm spring 132 is restored to the original position, when the LF motor 26 rotates in the forward direction from here, the double-sided pendulum arm 117 is moved to the arrow a in FIGS. Although the follower pin 127a is in the vicinity of the innermost circumference of the spiral groove gear 120, the double-sided pendulum arm spring 132 comes into contact with the stop arm 127, and the first double-sided planetary gear 118 is The double-sided roller idler gear 124 cannot be engaged. Further, even when the LF motor 26 is rotated in the forward direction, the follower pin 127a continues to rotate on the innermost circumference of the spiral groove gear 120, so that the first double-side roller 108 and the second double-side roller 109 are not driven. .

  That is, in the double-sided recording apparatus according to the present embodiment, after the recording sheet material 4 is conveyed from the sheet material reversing unit 2 and the recording sheet material is sandwiched by the paper feed roller 21 again, the rear end of the recording sheet material 4 The reversing unit roller 108 is configured not to rotate in synchronization with the paper feed roller 21 until the recording sheet material discharge operation is completed after the roller is separated from the reversing unit roller 108.

  In the configuration described above, the paper feed roller 21 is rotated by a predetermined amount in the second rotation direction (forward direction) in which the recording sheet material 4 is conveyed in the direction from the sheet material reversing unit 2 toward the paper feed roller 21. The reversing section roller 108 does not rotate synchronously with the paper feed roller 21 by the second clutch means (see FIGS. 15 and 16) that is cut by rotating a predetermined amount in the first rotation direction (reverse direction). It is taken. Further, the second clutch means includes mechanisms 120, 127, and 132 that restrain the swing arm 117 that holds the planetary gears 118 and 119. Furthermore, the second clutch means includes a time difference mechanism using a spiral end face cam (spiral groove gear 120) and a cam follower (stop arm 127).

  In the configuration described above, as described above, after recording on the first surface (front side surface), the driving of the paper feed roller 21 is started, and then the leading end of the recording sheet material 4 is the sheet material reversing portion. The second double-sided roller 109 is configured to start synchronous rotation with the paper feed roller 21 before being sandwiched by the second second double-sided roller 109. Second double-sided roller by first clutch means (see FIGS. 15 and 16) connected by rotating a predetermined amount in the first rotation direction (reverse direction) for conveying the sheet material 4 to the sheet material reversing unit 2 109 is configured to start synchronous rotation with the paper feed roller 21.

  In the state shown in FIG. 16 (f), as described above, the first reverse delay gear 121 is initialized in step S19 or step S21. Therefore, in step S26, all the initial driving mechanisms of the rollers are initialized. The conversion ends.

  This completes the automatic double-sided recording operation. When the automatic duplex recording operation is continuously performed, the above-described sequence may be repeated.

  In this embodiment, the double-sided pendulum arm spring 132 as described above realizes an elastic contact relationship between the double-sided pendulum arm 117 and the stop arm 127. It is also possible to adopt a configuration as shown in FIG. FIG. 17 is a schematic cross-sectional side view showing the operating state of the driving mechanism of the rollers of the automatic duplex unit 2 as in FIG. The double-sided pendulum arm 117 in FIG. 17 has a low-elasticity arm, and the arm and the stop arm 127 are in contact with each other. The operation of this configuration will be briefly described below.

  Since the operation from FIG. 17A to FIG. 17C is the same as the operation from FIG. 16A to FIG. 16C, the description thereof is omitted here.

  FIG. 17D shows a state where the stop arm 127 has moved in the inner circumferential direction of the spiral groove gear 120 and has come into contact with the arm 142 of the swing arm (double-sided pendulum arm) 117. Since the arm 142 of the double-sided pendulum arm 117 is not very elastic, a force that rotates the double-sided pendulum arm 117 in the direction of arrow b in FIG. The force acts in a direction to disengage the first double-sided planetary gear 118 and double-sided roller idler gear 124. The force to disengage is balanced with the pressure acting between the tooth surfaces of the first double-sided planetary gear 118 and the double-sided roller idler gear 124 and the elasticity and sliding force of the gear tooth surfaces, but the follower pin 127a eventually becomes the inner circumference. As the force moves, the force to disengage becomes larger, overcomes the force between the tooth surfaces, and forcibly disengages the first double-sided planetary gear 118 and double-sided roller idler gear 124. Simultaneously with the release of the engagement, the rotation of the first double-sided roller 108 and the second double-sided roller 109 stops. FIG. 17E shows this state. The timing for stopping the rotation of the roller is performed at an appropriate time after the rear end of the back side surface of the recording sheet material 4 passes through the first double-sided roller 108 in step S23.

  That is, in the configuration of FIG. 17, in place of the second clutch means described in FIG. 16, the third clutch that is cut by rotating the paper feed roller 21 by a predetermined amount in the second rotation direction (forward direction). By using the means 120, 127, 142, the reversing unit roller 108 is configured not to rotate in synchronization with the paper feed roller 21. Further, the third clutch means in the configuration of FIG. 17 includes a mechanism for forcibly displacing the swing arm 117 that holds the planetary gears 118 and 119, and furthermore, a spiral end face cam (spiral groove gear). 120) and a time difference mechanism by a cam follower (stop arm 127).

  In the double-sided recording apparatus having the mechanism shown in FIG. 17, as described above, after recording on the first surface (front surface), the drive of the paper feed roller 21 is started and then the recording sheet material 4 is recorded. The second double-sided roller 109 is configured to start synchronous rotation with the paper feed roller 21 until the leading end is nipped by the second double-sided roller 109 of the sheet material reversing unit 2. By first clutch means (see FIGS. 15 and 16) connected by rotating the feed roller 21 by a predetermined amount in the first rotation direction (reverse direction) for conveying the recording sheet material 4 to the sheet material reversing unit 2. The second double-sided roller 109 is configured to start synchronous rotation with the paper feed roller 21.

  After the gear disengagement as shown in FIG. 17C, the stop arm 127 causes the double-sided pendulum arm 117 to swing in the direction of arrow a in FIG. 17 even if the LF motor 26 rotates in the forward direction. Since it is obstructed, the automatic duplex unit 2 is not driven until the LF motor 26 rotates a predetermined amount in the reverse direction next time. Similarly to the first embodiment, since the first reverse delay gear 121 is also initialized in step S19 or step S21, initialization of the driving mechanism of the rollers of the automatic duplex unit 2 is completed at this point. is doing. As a result, it is possible to eliminate the load of rotating the first double-sided roller 108 and the second double-sided roller 109 during the recording operation on the back side, and to reduce the rotational load of the LF motor 26.

[Change carriage position]
Next, a case where the carriage position is changed depending on the type of the recording sheet material 4 on which recording is performed will be described. Depending on the recording sheet material 4, it may be warped due to stored environmental conditions, or it may be warped after the recording is finished due to the recording ink being liquid. The recording unit 11 and the recording sheet material 4 being conveyed are arranged so that the recording operation is performed at a predetermined interval. If the warp of the recording sheet material 4 is larger than this interval, the recording is performed. There is a possibility that the portion 11 and the recording sheet material 4 come into contact with each other. Three examples are shown below.

  The first example is a case where the recording sheet material 4 is warped before feeding to the recording apparatus. Examples thereof include an official postcard for inkjet and a sheet material having a coating layer for absorbing ink on one side. If these recording sheet materials 4 are left in a low-humidity environment, they may be warped in a direction determined from the perforations of the sheet material and the position of the coating layer. If they are conveyed as they are, the recording sheet material 4 is removed from the nip portion of the pinch roller 22 at the end of the recording operation on the front side surface and is held by the discharge roller and the spur. The end portion of the sheet material 4 may warp and come into contact with the recording portion (end surface of the recording head 11). If contact is made, ink adheres to an unintended portion of the recording sheet material 4 or, if bad, the recording portion hits the side edge of the recording sheet material 4 as the carriage 13 scans, and the recording sheet material 4 There is a possibility that the position of the sheet material 4 is shifted. Therefore, when this type of recording sheet material 4 is used, the carriage 13 is moved in advance to the second carriage position, that is, the end surface of the recording head 11 as shown in FIG. It is convenient to set the position where the interval S2 is generated between the recording sheet materials 4. At this time, during the recording operation on the back side surface, the warping direction of the recording sheet material 4 is opposite to the front side surface, so that the possibility of contact between the recording portion and the recording sheet material 4 is low. From the first carriage position (set to be suitable for recording the recording sheet 4 in a normal state), that is, the end face of the recording head 11 as shown in FIG. The recording operation can be carried out by returning to the position where the interval S1 occurs between the recording sheet materials 4. The above is a case where the recording operation is performed at the second carriage position on the front surface and the first carriage position on the rear surface.

  The second example is the case of the recording sheet material 4 that easily deforms due to ink absorption. Examples thereof include a sheet material that is thin and weak, or a sheet material that uses paper fibers that easily swell. When recording is performed on these recording sheet materials 4, the amount of deformation of the sheet material gradually increases to a certain amount as time passes after ink absorption. During the recording operation on the front side surface, the distance between the recording portion and the recording sheet material 4 may be close. However, when recording the back side surface, the recording sheet material 4 is already large due to undulation caused by ink absorption. Since it is deformed, there is a possibility that the recording portion and the recording sheet material 4 come into contact with each other. Therefore, when this type of recording sheet material 4 is used, it is preferable that the carriage is set to the second carriage position only during recording on the back side surface. The above is a case where the recording operation is performed at the first carriage position on the front surface and the second carriage position on the back surface.

  The third example is a case where recording is performed on a sheet material having the above two properties at the same time. In this case, it is preferable that the carriage 13 is always set to the second carriage position because there is a possibility that the recording portion and the recording sheet material 4 come into contact with each other on the front side surface and the back side surface. This is a case where the recording operation is performed at the second carriage position on both the front side surface and the back side surface.

  The above three carriage positions can be selected by various methods. For example, when the user operates a carriage position selection unit such as a switch added to the recording apparatus main body, when selecting according to the sheet material type set by the user when recording operation is instructed by the host device 308, or recording by the sheet material detection unit For example, the type of the recording sheet material may be detected by the recording apparatus main body, or the deformation amount of the recording sheet material may be detected by the recording apparatus main body by the deformation amount detection unit.

  In consideration of the case of using the recording sheet material 4 that is less likely to warp, the recording surface and the recording sheet material 4 have a small interval between the recording portion and the recording sheet material 4 on the front side surface and the back side surface as in the conventional recording apparatus. It is preferable that the recording operation can be performed at the first carriage position that is suitable in terms of quality. In that case, four carriage positions are selected by any of the methods described above. Further, using the double-sided recording apparatus of the present embodiment, with respect to the recording sheet material 4 that is very thick or has high rigidity, only the front side recording is performed without performing the front / back reversal and the recording on the back side. Single-sided recording is also possible.

  The above is the description including the automatic duplex recording operation along the flowchart showing the operation sequence of the duplex recording apparatus of the present embodiment.

  Note that the present invention is not limited to the above-described configuration, and can be controlled by changing the position of the lift mechanism described in FIG. That is, in the above-described embodiment, the sheet passing guide 70 is in the raised state in the normal standby state, but it is also possible to make it lower. Specifically, the lift mechanism is normally set to the third position as shown in FIG. 10C, and the lift mechanism is changed from the third position to the first position as shown in FIG. 10A before step S1. It is good to add the control to move. Further, after step S26, control for moving the lift mechanism from the first position to the third position may be added. In such a configuration, the pinch roller 22 is in the released state in the standby state, which is suitable for feeding thick paper or the like from the paper discharge roller side.

  In the present embodiment, a serial type recording apparatus that performs recording while moving the recording head 11 serving as a recording unit in the main scanning direction has been described as an example. The same effect can be applied to a line type recording apparatus that performs recording while performing only sub-scanning (paper feed) using a line type recording means of a length that covers a part. It can be achieved.

  In the above description, the configuration in which two or three carriage positions (interval between the recording unit and the recording sheet material) can be selected at the time of recording has been described. However, a configuration in which a larger number of carriage positions (intervals) can be selected. The interval can be set steplessly.

  Further, the present invention can be freely implemented regardless of the number of recording means, and for color recording using a plurality of recording means using different color inks in addition to a recording apparatus using one recording means. The present invention can be similarly applied to a recording apparatus for gradation recording using a plurality of recording means that use inks of the same color and different densities, and a recording apparatus that combines these recording apparatuses. The same effect can be achieved.

  Furthermore, in the present invention, when the recording apparatus is an ink jet recording apparatus, a configuration using a replaceable head cartridge in which the recording head 11 and the ink tank 12 are integrated, the recording head 11 and the ink tank 12 are separated, and these are used. The present invention can be similarly applied regardless of the arrangement configuration of the recording head 11 and the ink tank 12, such as a configuration in which a gap is connected by an ink supply tube or the like, and the same effect can be obtained. is there.

  In the present invention, when the recording apparatus is an ink jet recording apparatus, in addition to the recording apparatus using an ink jet recording head that discharges ink using thermal energy, for example, an electromechanical transducer such as a piezo element, etc. It can be similarly provided to an ink jet recording apparatus using another ink discharge method, such as a recording device using an ink jet recording head of a method of discharging ink, and can achieve the same operation and effect. is there.

1. Recording device body (recording unit body)
2 Sheet material reversing part (automatic duplex unit)
4 Recording sheet material (recording medium)
DESCRIPTION OF SYMBOLS 10 Chassis 11 Recording head 12 Ink tank 13 Carriage 14 Guide shaft 15 Guide rail 16 Carriage belt 17 Carriage motor 21 Paper feed roller 22 Pinch roller 23 Pinch roller holder 24 Pinch roller spring 26 LF motor 29 Platen 30 1st discharge roller 31 Second discharge roller 32 First spur train 33 Second spur train 36 Maintenance unit (discharge recovery device)
37 Main ASF (automatic paper feeder)
39 Feed roller 40 Separating roller 41 Pressure plate 44 ASF flap 46 ASF motor 47 ASF pendulum arm 48 ASF sun gear 49 ASF planetary gear 55 Guide shaft spring 56 Guide slope 57 Guide slot 58 Lift cam shaft 59 Pinch roller holder Press cam 60 Pinch roller Spring pressing cam 61 PE sensor lever pressing cam 65 Paper passing guide pressing cam 66 PE sensor lever (sheet material detection lever)
67 PE sensor 68 PE sensor lever spring 70 Paper feed guide (guide member)
71 Paper passing guide spring 74 Guide shaft spring 102 Inner guide 103 Rear cover 104 Switching flap (movable flap)
105 switching flap spring 106 outlet flap 107 outlet flap spring 108 first reverse roller (first double-sided roller)
109 Second reversing roller (second double-sided roller)
112 First double-sided pinch roller 113 Second double-sided pinch roller 116 Double-sided sun gear 117 Swing arm (double-sided pendulum arm)
118 First double-sided planetary gear 119 Second double-sided planetary gear 120 Spiral groove gear (end face cam)
121 First reverse delay gear 122 Second reverse delay gear 123 Reverse delay gear spring 124 Double-sided roller idler gear 125 First double-sided roller gear 126 Second double-sided roller gear 127 Stopper arm (cam follower)
127a Follower pin 128 Stopper arm spring 131 Retraction path 132 Swing arm spring (double-sided pendulum arm spring)
142 Arm 301 Control board 305 ASF sensor 307 Head driver 308 Host device (host computer)
310 CPU
311 ROM
312 RAM

Claims (6)

A carriage for moving by mounting a recording head for discharging ink to record on a sheet material;
A guide shaft for guiding the movement of the carriage;
A conveyance roller for conveying the sheet material on the upstream side of the recording head in the conveyance direction of the sheet material when recording by the recording head;
A sheet material reversing unit for reversing the front and back of the sheet material recorded on the first surface by the recording head;
With
The sheet material recorded on the first surface is conveyed to the sheet material reversing portion by rotating the conveyance roller in the direction opposite to the time when recording is performed by the recording head, and the sheet is conveyed by the recording head. An inkjet recording apparatus for recording on a second surface of a material,
By moving the guide shaft, the interval between the recording head and the sheet material when recording is performed on the second surface, and the recording head and the sheet material when recording is performed on the first surface. An ink jet recording apparatus characterized in that it is larger than the distance between the ink jet recording apparatus and the ink jet recording apparatus.   The inkjet recording apparatus according to claim 1, wherein the guide shaft is moved by rotating a cam disposed on the guide shaft.   The inkjet recording apparatus according to claim 2, wherein the guide shaft is supported by a chassis, and movement in a conveying direction of the sheet material and a movement direction of the carriage is restricted.   The sheet material reversing unit includes a second double-sided roller for reversing the front and back of the sheet material in contact with the first surface of the sheet material recorded by the recording head, and the front and back of the sheet material. A first double-sided roller disposed on the downstream side of the second double-sided roller in the advancing direction of the sheet material at the time of reversing and in contact with the first surface to reverse the front and back of the sheet material; The ink jet recording apparatus according to claim 1, further comprising: an ink jet recording apparatus according to claim 1.   By moving the guide shaft after recording is performed on the first surface, an interval between the recording head and the sheet material when the sheet material is transported to the sheet material reversing portion is set. And a distance between the recording head and the sheet material when recording on the second surface and a distance between the recording head and the sheet material when recording on the second surface. Item 10. The ink jet recording apparatus according to Item 1. A carriage for moving by mounting a recording head for discharging ink to record on a sheet material;
A conveyance roller for conveying the sheet material on the upstream side of the recording head in the conveyance direction of the sheet material when recording by the recording head;
A sheet material reversing unit for reversing the front and back of the sheet material recorded on the first surface by the recording head;
With
An ink jet recording apparatus in which a sheet material recorded on the first surface is conveyed to the sheet material reversing unit, and recording is performed on the second surface of the sheet material by the recording head;
The interval between the recording head and the sheet material when recording on the second surface is made larger than the interval between the recording head and the sheet material when recording on the first surface. An ink jet recording apparatus.

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