JP2004331400A - Double side recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double face recording device capable of achieving recording without a margin in the whole area of a recorded medium and ensuring nipping and holding of the recorded medium again by a paper feeding roller and a pinch roller by conveying it into a clearance between the paper feeding roller and the pinch roller for separating the recorded medium before deformation due to absorption of ink when conveying it in the reverse direction to prevent the occurrence of paper jamming. <P>SOLUTION: The recorded medium is conveyed up to a position where a paper rear end comes off a pair of paper feeding rollers 21, 22 when recording on a first face to separate the paper feeding roller from the pinch roller. Next, the paper feeding roller and the pinch roller are brought into pressure contact again after conveying the recorded medium up to the pair of paper feeding rollers in the reverse direction when recording on the first face by a pair of paper delivery rollers 30, 32. Furthermore, conveyance in the reverse direction is continued to convey the recorded medium into a paper inversion part 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a double-sided recording apparatus capable of performing double-sided recording on a recording medium that is reversed upside down by a sheet reversing unit, and additionally, a paper feed roller pair including a paper feed roller and a pinch roller, and a transport direction more than the paper feed roller pair. The present invention relates to the double-sided recording apparatus provided with a paper transport mechanism having a paper discharge roller pair disposed downstream.

  2. Description of the Related Art Conventionally, several methods have been implemented or proposed for performing automatic double-sided recording with an ink jet recording apparatus. After the recording on the front side (front side) of the recording paper is completed, the transport direction is reversed and the recording paper is sent to the reversing device, and after the reversing operation is completed, the same paper transport is performed again. The recording paper is conveyed in the recording section, and recording is performed on the back surface of the recording paper in the same recording section.

In those systems, as in the invention disclosed in US Pat. No. 6,332,068, when the recording operation on the surface of the recording paper is completed, the recording paper is kept nipped by the paper feed roller, In some cases, the recording sheet is transported to a front / back reversing unit by reversing the rotation direction. Further, as disclosed in Japanese Patent Application Laid-Open No. 2002-067407, when the surface recording operation of the recording paper is completed, the recording operation is performed while the recording operation is being performed to the downstream side where the paper feeding roller has already been released, and then the recording paper is transported in the transport direction. In some cases, the recording paper is nipped again by the paper feed roller by using a guide member. Further, in any of the above methods, the portion where the recording on the front surface (front surface) is completed and the ink is fixed is nipped again by the paper feed roller and conveyed.
USP63332068 JP-A-2002-067407

  However, there are some restrictions in the above conventional example. In other words, in the invention disclosed in Patent Document 1 (US Pat. No. 6,332,068), a sheet feed roller needs to hold a sheet by a sheet feed roller (a pinch allowance). However, it is inevitable that a margin where recording operation is impossible remains at the rear end of the front surface. Further, in the invention disclosed in Patent Document 2 (Japanese Patent Application Laid-Open No. 2002-067407), it is possible to set the margin at the rear end of the surface to zero. Since deformation such as waving due to the influence of swelling of the recording paper occurs, there is a possibility that a paper jam occurs when the recording paper is sandwiched again by the paper feed roller. Furthermore, since the portion of the recording paper on which the ink is fixed is conveyed while being sandwiched again by the paper feed roller, it is necessary to wait for the ink to completely dry and fix. In order to prevent the ink from being transferred to the roller side, it is necessary to secure a sufficient drying standby time.

  The present invention has been made in view of the above technical problems, and an object of the present invention is to perform recording without margins over the entire range of a recording medium, and to feed paper in a reverse direction. An object of the present invention is to provide a double-sided recording apparatus capable of reliably holding a recording medium again by a roller and a pinch roller, and reliably preventing a paper jam or a paper jam.

  In order to achieve the above object, the present invention provides a paper feed roller pair including a paper feed roller and a pinch roller pressed against the paper feed roller, and at least one paper feed roller disposed downstream of the paper feed roller pair in the transport direction. In a double-sided recording apparatus provided with a paper transport mechanism having a pair of paper discharge rollers and a paper discharge roller pair composed of a rotating body pressed against the paper discharge rollers, the trailing edge of the recording medium during the first-side recording is performed first. The recording medium can be conveyed to a position where the recording medium is disengaged from the paper feed roller pair. Then, the paper feed roller and the pinch roller are separated from each other, and the recording medium is received by the paper discharge roller pair in a direction opposite to that of the first surface recording. After the recording medium is conveyed, the recording medium is conveyed to the sheet reversing unit by pressing the paper feed roller and the pinch roller again and continuing the conveyance in the reverse direction.

  According to the present invention, it is possible to perform recording without margins over the entire range of the recording medium, and to reliably convey the recording medium again by the paper feed roller and the pinch roller when conveying in the reverse direction. Also, a double-sided recording apparatus capable of reliably preventing paper jams and paper jams is provided.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. FIG. 1 is a schematic perspective view showing an overall configuration of an embodiment of a recording apparatus to which the present invention is applied, and FIG. 2 is an overall configuration of the recording apparatus according to the embodiment as viewed from the direction of arrow A in FIG. It is a typical side sectional view shown. 1 and 2 show a case where the recording apparatus is an ink jet recording apparatus that performs recording on a recording medium by discharging ink. In the following description, the recording paper (recording paper) is a representative example of the recording medium, and the place where the recording medium in a broad sense should be used may be called the recording paper or paper. The range of the recording medium is not limited to paper (recording paper).

  1 and 2, 1 is a recording unit main body, 2 is an automatic double-sided unit (paper reversing unit, automatic reversing unit), 10 is a chassis that supports the structure of the recording unit main body 1, and 11 performs recording by discharging ink. A recording head 12, an ink tank for storing ink to be supplied to the recording head 11, a carriage 13 for holding and scanning (main scanning) the recording head 11 and the ink tank 12, and a guide shaft 14 for guiding and supporting the carriage 13 , 15 are guide rails for guiding and supporting the carriage 13 in parallel with the guide shaft 14, 16 is a carriage belt (timing belt) for driving the carriage 13, 17 is a carriage motor for driving the carriage belt 16 via pulleys, 18 Is a code strip for detecting the position of the carriage 13, and 20 is a carrier. A idler pulleys for stretching the carriage belt 16 and pulley facing the Jimota 17.

  Reference numeral 21 denotes a paper feed roller that conveys a recording medium (recorded paper), 22 denotes a pinch roller that is pressed by the paper feed roller 21 and follows the pinch roller, 23 denotes a pinch roller holder that rotatably holds the pinch roller 22, and 24 denotes a pinch roller. A pinch roller spring for pressing the roller 22 against the paper feed roller 21; 25, a paper feed roller pulley fixed to the paper feed roller 21; 26, an LF motor for driving the paper feed roller 21; A code wheel 29 for detecting the angle is a platen that supports the recording sheet facing the recording head 11.

  Reference numeral 30 denotes a first paper discharge roller for conveying the recording medium in cooperation with the paper feed roller 21, 31 a second paper discharge roller provided downstream of the first paper discharge roller 30, and 32 a first paper discharge roller. A first spur train as a rotating body that faces the discharge roller 30 and holds the recording medium; 33, a second spur train as a rotating body that faces the second discharge roller 31 and holds the recording medium; Reference numeral 34 denotes a spur base for rotatably holding the first spur train 32 and the second spur train 33, and 36 prevents and prevents clogging of the recording head 11 (clogging of discharge ports and nozzles) to maintain and recover ink discharge performance. And a maintenance unit 37 that operates when ink is distributed to the ink flow path of the print head when the ink tank 12 is replaced. The automatic supply 37 loads the recording medium and supplies it to the recording unit one by one during the recording operation. Main A as paper It is a F (AutomaticSheetFeeder).

  1 and 2, reference numeral 38 denotes an ASF base serving as a base of the main ASF 37; 39, a paper feed roller which abuts and transports a stacked recording medium (recording paper); and 40, a plurality of recording media. A separation roller 41 that separates the recording media one by one when they are transported at the same time; 41 is a pressure plate for stacking the recording media and urging the recording media toward the paper feed roller 39; The side guide 43, which can be fixed at an arbitrary position, returns the leading end of the recording medium (recording sheet) that has advanced beyond the nip portion between the sheet feeding roller 39 and the separation roller 40 during the sheet feeding operation to a predetermined position. A return flap 44 is an ASF flap that regulates the recording medium passing direction from the main ASF 37 in one direction.

  Reference numeral 50 denotes a lift input gear that engages with the ASF planetary gear 49, 51 denotes a lift reduction gear train that transmits the power from the lift input gear 50 while reducing the power, 52 denotes a lift cam gear directly connected to the lift cam shaft, and 55 denotes a part of the guide shaft 14. A guide shaft spring for urging the guide shaft 56, a guide slope 56 on which a cam of the guide shaft gear 53 slides, a lift cam shaft 58 for lifting the pinch roller holder 23, etc., and a paper feed roller 70 for the leading end of the recording medium A paper passing guide for guiding to the nip portion between the pinch roller 21 and the pinch roller 22, a base 72 for supporting the entire recording unit body 1, and a control board 301 for controlling the control unit.

  FIG. 21 is a block diagram showing driving means for driving the entire recording apparatus to which the present invention is applied. In FIG. 21, reference numeral 19 denotes a CR (carriage) encoder sensor mounted on the carriage 13 to read the code strip 18; 28, an LF encoder sensor to read the code wheel 27 attached to the chassis 1; 46, an ASF motor for driving the main ASF 37; 67 is a PE sensor for detecting the operation of the PE sensor lever 66, 69 is a lift cam sensor for detecting the operation of the lift cam shaft 58, and 130 is a double-sided unit sensor for detecting attachment / detachment of the automatic double-sided unit 2.

  21, reference numeral 302 denotes a PG motor for driving the maintenance unit 36, 303 a PG sensor for detecting the operation of the maintenance unit 36, 305 an ASF sensor for detecting the operation of the main ASF 37, and 307 a head driver for driving the recording head 11. , 308 is a host device for sending recording data to the present recording device, 309 is an I / F (interface) for electrically connecting the host device 308 to the present recording device, and 310 is a control command for controlling the present recording device. A reference numeral 311 denotes a ROM in which control data and the like are written, and a reference numeral 312 denotes a RAM serving as an area for expanding recording data and the like.

  Here, the outline of the recording apparatus according to the present embodiment will be described with reference to FIGS. 1, 2, and 21, and then the operation of each unit will be described. First, the configuration of a general serial scanning type recording apparatus will be described. The recording apparatus according to the present embodiment is roughly divided into a paper feed unit, a recording medium transport unit (paper transport unit), a recording unit, a recording unit (recording head) maintenance unit, and an automatic reversing unit (automatic duplex unit unit). It is composed of When print data is sent from the host device 308 and stored in the RAM 312 via the interface (I / F) 309, the CPU 310 issues a print operation start command and starts the print operation.

  When recording is started, first, a paper feeding operation is performed. The paper feed unit is a main ASF (Automatic Sheet Feeder). The paper feed unit pulls out one recording medium from recording media (recording paper) stacked on the pressure plate 41 for each recording operation. An automatic paper feed unit that feeds the recording medium transport unit (paper transport unit). At the start of the sheet feeding operation, the ASF motor 46 rotates in the forward direction, and the motive power rotates the cam holding the pressure plate 41 via the gear train. When the cam is released by the rotation of the ASF motor 46, the pressure plate 41 is urged toward the paper feed roller 39 by the action of a pressure plate spring (not shown). At the same time, since the paper feed roller 39 rotates in the direction in which the recording medium (paper) is conveyed, conveyance of the top sheet of the stacked recording medium is started. At this time, a plurality of recording sheets may be sent out at the same time depending on the conditions of the frictional force between the paper feed roller 39 and the recording sheets and the frictional force between the recording sheets.

  In this case, a separation roller 40 which is pressed against the paper feed roller 39 and has a predetermined return rotational torque in a direction opposite to the recording paper conveyance direction acts. It functions to push recording paper other than recording paper back onto the original pressure plate. At the end of the ASF paper feeding operation, the separation 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. In order to push back the paper, the return claw 43 rotates and plays a role. By the operation described above, only one sheet of recording paper is transported to the paper transport unit.

  When one recording sheet is conveyed from the main ASF 37, the leading end of the recording sheet comes into contact with the ASF flap 44 urged by the ASF flap spring in a direction obstructing the sheet passing path. The flap 44 is pushed away and passes. When the recording operation of the recording paper is completed and the trailing edge of the recording paper passes through the ASF flap 44, the ASF flap 44 returns to the original biased state and the paper passage path is closed. Even if transported, it does not return to the main ASF 37 side.

  The recording paper conveyed from the paper supply unit is conveyed toward a nip between a paper feed roller (conveyance roller) 21 serving as a paper conveyance unit (recording medium conveyance unit) and a pinch roller 22. Since the center of the pinch roller 22 is attached with a slight offset in the direction approaching the first discharge roller 30 with respect to the center of the paper feed roller 21, the tangential angle at which the recording paper is inserted is It is slightly inclined from horizontal. Therefore, the paper (recording paper) is conveyed at an angle in a paper passing path formed by the pinch roller holder 23 and the guide member (paper passing guide) 70 so that the leading end of the paper is accurately guided to the nip portion. Like that.

  The paper conveyed (supplied) by the ASF 37 is abutted against the nip portion of the paper feed roller 21 in a stopped state. At this time, a paper loop is formed between the paper feed roller 39 and the paper feed roller 21 by transporting the main ASF 37 for a distance slightly longer than the predetermined paper passage path length. When the leading end of the sheet is pressed against the nip portion of the paper feed roller 21 by the force that tries to return the loop straight, the leading end of the sheet 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 (transport motor) 26 is started to rotate in the direction in which the recording sheet moves in the forward direction (the direction in which the recording sheet advances toward the first discharge roller 30). After that, the driving force of the paper feed roller 39 is cut off, and the paper feed roller 39 rotates together with the recording paper. At this point, the recording paper is conveyed only by the paper feed roller 21 and the pinch roller 22. The paper advances in the forward direction at every predetermined line feed amount, and advances along a rib provided on the platen 29.

  The leading edge of the paper gradually gets over the nip portion between the first discharge roller 30 and the first spur train 32 and the nip portion between the second discharge roller 31 and the first spur train 33, but the first discharge roller 30 and the second spur train 33 The peripheral speed of the paper roller 31 is set substantially equal to the peripheral speed of the paper feed roller 21, and the first discharge roller 30 and the second discharge roller 31 are connected from the paper feed roller 21 by a gear train. The first discharge roller 30 and the second discharge roller 31 rotate in synchronization with the paper feed roller 21, so that the recording sheet is conveyed without being loosened or pulled. The paper feed roller (paper transport roller) 21 and the pinch roller 22 constitute a paper feed roller pair. The first discharge roller 30 and the first spur train 32 constitute a first discharge roller pair, and the second discharge roller 31 and the second spur train 33 constitute a second discharge roller pair. A pair of discharge rollers is constituted by the first discharge roller pair and the second discharge roller pair.

  The recording section mainly includes a recording head 11 serving as recording means for recording on a recording sheet based on recording data, and a scanning section in which the recording head 11 is mounted and intersects (usually orthogonal) with the recording sheet transport direction. (Moving) carriage 13. The carriage 13 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 via a carriage belt 16 stretched between a carriage motor 17 and an idler pulley 20. By transmitting the driving force of the carriage motor 17, the carriage reciprocates (scans).

  A plurality of ink flow paths connected to the ink tank 12 are formed in the recording head 11, and the ink flow paths communicate with discharge ports provided on a surface (discharge port surface) facing the platen 29. An actuator for discharging ink is arranged inside each of the plurality of discharge ports forming the discharge port array. As this actuator, for example, an actuator utilizing the film boiling pressure of a liquid by an electrothermal converter (heating element) or an electromechanical converter (electric-pressure converter) such as a piezo element is used.

  In an ink-jet recording apparatus using the above-described recording head 11 as a recording apparatus, a signal of a head driver 307 is transmitted to the recording head 11 via a flexible flat cable 73 to eject ink droplets in accordance with recording data. It is possible to Further, by reading the code strip 18 stretched on the chassis 10 by a CR (carriage) encoder 19 mounted on the carriage 13, it is possible to discharge ink droplets toward the recording paper at an appropriate timing. In this manner, when recording for one line is completed, the recording paper is conveyed (paper feed) by a required amount by the paper conveyance unit (recording medium conveyance unit). By repeating this operation, a recording operation over the entire surface of the recording paper can be performed.

  The print head maintenance unit prevents the discharge ports of the print head 11 from being clogged, and eliminates the contamination of the discharge port surface of the print head 11 by paper dust or the like, so that the print operation of the print head 11 is in a normal state. It is for maintaining and recovering. As a recovery mechanism for this purpose, for example, a capping mechanism that covers the discharge port, a suction recovery mechanism that suctions and discharges ink from the discharge port in a capping state, and a wiping mechanism that wipes and cleans the periphery of the discharge port are used.

  That is, the maintenance unit 36, which is installed at the standby position of the carriage 13 so as to face the recording head 11, comes into contact with the discharge port surface (the surface on which the discharge port is formed) of the recording head 11 to protect the discharge port. , A suction recovery mechanism having a suction pump connected to the cap and generating a negative pressure in the cap, and the like. When sucking ink to refresh the ink in the ejection port of the recording head 11, the cap is pressed against the ejection port surface, and the suction pump is driven to make the inside of the cap a negative pressure, thereby sucking and discharging the ink. In addition, if ink adheres to the ejection port surface after ink suction or foreign matter such as paper powder adheres to the ejection port surface, remove the wiper by moving the wiper in contact with the ejection port surface and moving it in parallel. By doing so, the discharge port surface is wiped (wiped and cleaned) to remove extraneous matter.

  The above is the outline of the recording apparatus. Next, the configuration specific to the present embodiment, including the configuration of the automatic duplex unit 2 as a paper reversing unit or an automatic reversing unit, will be described in detail. The recording apparatus according to the present embodiment is capable of so-called automatic double-sided recording, which can automatically perform recording on both sides of a recording sheet made of sheet-shaped cut-sheet paper without bothering the operator. It is characterized by

  First, a passage of a recording medium (recording paper) will be described with reference to FIG. In FIG. 2, reference numeral 104 denotes a switching flap composed of a movable flap that determines the paper passing direction of a rotatably supported recording medium, and 106 denotes an outlet that is rotatably supported and opens and closes when the recording medium exits the duplex unit 2. A flap 108 is a double-sided roller A as a reversing roller for conveying a recording sheet (recording medium) in the double-sided unit 2, and a double-sided roller B 112 as a reversing roller for conveying the recording sheet in the double-sided unit 2. Denotes a double-sided pinch roller A driven by a double-sided roller A108, and 113 denotes a double-sided pinch roller B driven by a double-sided roller B109.

  When the recording operation is started, the recording paper is fed one by one from the plurality of recording papers stacked on the main ASF 37 by the action of the paper feed roller 39 and is fed (conveyed) to the paper feed roller 21. Is done. The recording paper sandwiched between the paper feed roller 21 and the pinch roller 22 is transported in the direction of arrow a in FIG. When double-sided recording is performed, after the front (front) side recording is completed, the recording sheet is conveyed in a horizontal path provided below the main ASF 37 in a direction indicated by an arrow b in FIG. Since the automatic duplex unit 2 as the automatic reversing unit is disposed behind the main ASF 37, the recording paper is guided into the automatic duplex unit 2 from a horizontal path, and is conveyed in the direction of arrow c in FIG.

  In the automatic double-sided unit 2, the recording sheet is nipped by the double-sided roller B109 and the double-sided pinch roller B113 to change the traveling direction, and further nipped by the double-sided roller A108 and the double-sided pinch roller A112 to be directed in the direction of arrow d in FIG. Finally, the traveling direction is changed by 180 degrees (turning), and the process returns to the horizontal path. The recording paper conveyed in the horizontal path in the direction of arrow a in FIG. 2 is again sandwiched between the paper feed roller 21 and the pinch roller 22, and recording on the back surface is performed. As described above, the recording sheet after the front side recording is turned over by the horizontal path below the main ASF 37 and the automatic double-sided unit 2 behind the main ASF 37, and the back side is recorded again. Recording is automatically performed on both sides.

  Here, the recording range at the time of recording the front surface (first surface, front surface) will be described. The recording head 11 has a discharge port area (recording area, ink discharge area) N between the paper feed roller 21 and the first paper discharge roller 30. It is usually difficult to arrange the discharge port region N immediately near the nip portion of the paper feed roller 21 due to the wiring to an actuator (discharge energy generating means) for discharging the ink. Therefore, in the range where the recording paper is sandwiched between the paper feed roller 21 and the pinch roller 22, printing is performed only to the range downstream of the nip portion of the paper feed roller 21 by a length L1 shown in FIG. 2. I can't.

  In order to reduce the margin area at the lower end of the front surface, in the recording apparatus according to the present embodiment, the recording paper is separated from the nip portion of the paper feed roller 21, and only the first paper discharge roller 30 and the second paper discharge roller 31 are used. Recording is continued up to the portion that is pinched and conveyed. As a result, the recording operation can be performed until the bottom margin of the front surface becomes zero. However, when the recording paper is to be conveyed from this state in the direction of the arrow b in FIG. 2, the recording paper cannot be guided (guided) to the nip portion between the paper feed roller 21 and the pinch roller 22 ( Or difficulties), so-called paper jams can occur. In the present embodiment, in order to avoid such a paper jam, a predetermined gap is formed by releasing (separating) the pinch roller 22 from the paper feed roller 21 by means described below. After the section is pulled in, the pinch roller 22 is again pressed against the paper feed roller 21 so that the recording paper can be transported in the direction of arrow b in FIG.

  Next, a release mechanism of the pinch roller 22, a release mechanism of the sheet detection lever (PE sensor lever) 66, a pressure adjustment mechanism of the pinch roller spring 24, and a guide member (paper passing guide), which are characteristic configurations of the present embodiment. The up-down mechanism 70 and the up-down mechanism of the carriage 13 will be described. As described above, the pinch roller 22 is operated to be released (separated or separated) from the paper feed roller 21 in order to re-retract the recording paper. However, after the recording paper is re-retracted, the front and back of the recording paper are reversed. There are several other mechanisms to make it work.

  One of them is a release mechanism of a PE sensor lever 66 as a sheet detection lever. The normal PE sensor lever 66 swings at a predetermined angle with respect to the surface of the recording sheet so that the position of the leading or trailing edge of the recording sheet can be accurately detected when the recording sheet advances in the forward direction. So that it is attached. With such a setting, when the sheet advances in the reverse direction, the end of the recording sheet may be caught or the leading end of the PE sensor lever 66 may bite into the recording sheet being conveyed. There is a technical problem. For this reason, in the present embodiment, the PE sensor lever 66 is released from the sheet surface up to the middle of the process of reversing the recording sheet so that the PE sensor lever 66 does not come into contact with the recording sheet.

  Note that the release mechanism of the PE sensor lever 66 is not necessarily an essential component, and can be replaced with another means or configuration. That is, as a means for solving the above-mentioned technical problem, a roller or the like is provided at the end of the PE sensor lever 66, and even if the recording paper advances in the reverse direction, the roller rotates to solve the above-mentioned technical problem. Means for solving the problem may be adopted. In addition, the swing angle of the PE sensor lever 66 is set to be large, and when the recording sheet is conveyed in the reverse direction, the PE sensor lever 66 swings in the opposite direction to the normal direction to solve the above-described technical problem. Means may be adopted.

  The other is a pressure adjusting mechanism for the pinch roller spring 24, that is, a pressure adjusting mechanism for changing the pressure (spring force) of pressing the pinch roller 22 against the paper feed roller 21. In the present embodiment, in order to release (separate) the pinch roller 22, the entire pinch roller holder 23 is rotated and released. When the pinch roller 22 is pressed against the paper feed roller 21, the pinch roller holder 23 is pressed by the pinch roller spring 24. Therefore, when the pinch roller holder 23 is rotated in the release direction, the pressure of the pinch roller spring 24 is reduced. It fluctuates in the increasing direction, and there are adverse effects 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.

  The other is a vertical mechanism of the paper passing guide. The guide member composed of the paper passing guide 70 transports the recording medium conveyed from the automatic paper feeding section 37 to the first paper passing path, and transports the recording medium to and from the automatic reversing section composed of the duplex unit 2. It forms a part of a shared portion with the second paper passing path for guiding the received recording medium. Normally, the paper passing guide 70 smoothly guides the recording paper fed from the main ASF 37 to the nip portion of the LF roller 21 which is slightly inclined from horizontal as described above in order to guide the recording paper fed to the paper feed roller 21. It is located at a position slightly higher than the horizontal path so as to guide the paper (the state shown in FIG. 2). However, if the recording paper is conveyed in the direction of the arrow b in FIG. 2, the recording paper will be guided again toward the main ASF 37, so that it is possible to prevent this and smoothly guide the paper to the horizontal path. Thus, it is preferable to change the angle so that the paper passing guide 70 is horizontal. For this purpose, an up-down mechanism for raising and lowering a paper passing guide 70 as a guide member is provided.

  The last one is a mechanism for raising and lowering the carriage 13. This is because when the pinch roller holder 23 is in a release state (a state separated from the paper feed roller 21), the leading end of the pinch roller holder 23 approaches the carriage 13, so that the two abut and the carriage 13 can move in the main scanning direction. This is to prevent it from disappearing. For this reason, a vertical mechanism for raising the carriage 13 in synchronization with the release operation of the pinch roller holder 23 is provided. The mechanism for raising and lowering the carriage 13 can be applied to other uses. For example, when recording on a thick recording sheet, the recording head 11 is retracted so that the recording head 11 does not contact the recording sheet. It can also be used when moving for the purpose of doing.

  Hereinafter, the above five mechanisms (the release mechanism of the pinch roller 22, the release mechanism of the PE sensor lever 66, the pressure adjustment mechanism of the pinch roller spring 24, the vertical mechanism of the paper feed guide 70, and the vertical mechanism of the carriage 13) will be described in detail. explain. FIG. 3 is a schematic perspective view showing a schematic configuration of a pinch roller release mechanism, a PE sensor lever release mechanism, a pinch roller spring pressure adjustment mechanism, and a paper passing guide up / down mechanism.

  3, reference numeral 59 denotes a pinch roller holder pressing cam that contacts the pinch roller holder 23; 60, a pinch roller spring pressing cam that acts as an action point of the pinch roller spring 24; and 61, a PE sensor lever pressing cam that contacts the PE sensor lever 66. And 62, a lift cam shaft shielding plate indicating the angle of the lift cam shaft 58, 65 is a paper passage guide pressing cam that contacts the paper passage guide 70, 66 is a PE sensor lever that contacts the recording paper and detects the leading edge and the trailing edge, 67 is a PE sensor that is transmitted / shielded by the PE sensor lever 66; 68 is a PE sensor lever spring that biases the PE sensor lever 66 in a predetermined direction; 69 is a lift cam sensor that is transmitted / shielded by the lift cam shaft shielding plate 62; Reference numeral 71 denotes a paper passing guide spring that biases the paper passing guide 70 in a predetermined direction.

  The pinch roller release mechanism, the PE sensor lever release mechanism, the pinch roller spring pressure adjustment mechanism, and the paper passing guide up / down mechanism operate by rotation of the lift cam shaft 58. In the mechanism of the present embodiment, the pinch roller holder pressing cam 59, the pinch roller spring pressing cam 60, the PE sensor lever pressing cam 61, and the paper passing guide pressing cam 65 are fixed to the lift cam shaft 58, respectively. Each cam operates in synchronization with one rotation of the cam 58. Here, the initial angle and one rotation of the lift cam shaft 58 are recognized when the lift cam shaft shielding plate 62 shields or transmits the lift cam sensor 69. It should be noted that the gist of the present invention is not limited to such a configuration, and a mechanism for independently driving each of them may be employed as needed.

  Next, the operation of each mechanism will be described. FIG. 4 is a partial side view schematically showing operations of the pinch roller release mechanism and the pinch roller spring pressure adjusting mechanism. FIG. 4A shows a case where the pinch roller holder pressing cam 59 is at the initial position, the pinch roller 22 is in pressure contact with the paper feed roller 21, and the pressure of the pinch roller spring 24 is in a standard state. The pinch roller holder 23 is rotatably supported by a bearing portion of the chassis 10 on a pinch roller holder shaft 23a, and is configured to be swingable over a predetermined angle range. The pinch roller 22 is rotatably supported at one end of the pinch roller holder 23, and an area that contacts the pinch roller holder pressing cam 59 is provided at the other end.

  4A, one end of the pinch roller spring 24 is brought into contact with the pinch roller 22 side of the pinch roller holder 23 as a point of force, the other end is supported by a pinch roller spring pressing cam 60, and the spring intermediate portion is The torsion coil spring is supported by the support of the chassis 10. With such a supporting form, the pinch roller 22 is pressed against the paper feed roller 21 at a predetermined pressure. If the rotation drive mechanism of the paper feed roller 21 is operated in this state, the recording paper sandwiched between the nip portion between the paper feed roller 21 and the pinch roller 22 can be conveyed.

  FIG. 4B shows a case where the pinch roller 22 is in a released (separated) state and the pinch roller spring 24 is in a state of unloading. That is, when the lift cam shaft 58 rotates in the direction of arrow a in FIG. 4, the pinch roller holder pressing cam 59 comes into contact with the pinch roller holder 23, and the pinch roller holder 23 gradually rotates in the direction of arrow b in FIG. As a result, the pinch roller 22 is released (separated or separated) from the paper feed roller 21. In the state shown in FIG. 4B, the contact surface of the pinch roller spring pressing cam 60 with the pinch roller spring 24 has a small radius, and the torsion angle θ2 of the pinch roller spring 24 is as shown in FIG. ), The spring load is reduced, and the pinch roller holder 23 is hardly loaded. Thus, the pinch roller holder 23 is hardly stressed. In this state, a predetermined amount of gap H is formed between the paper feed roller 21 and the pinch roller 22, so that the leading edge of the recording paper roughly (roughly) guided (guided) can be easily nipped. It is possible to insert into the part.

  FIG. 4C shows a case where the pinch roller 22 is in pressure contact with the paper feed roller 21 as in FIG. In the state shown in FIG. 4C, when the lift cam shaft 58 further rotates in the direction of arrow a in FIG. 4, the contact between the pinch roller holder pressing cam 59 and the pinch roller holder 23 is released, and the pinch roller holder 23 is released. Is rotated in the direction of arrow c in FIG. 4 to return to the original state, and the pinch roller spring pressing cam 60 has a contact surface with the pinch roller spring 24 shown in FIG. 4A and FIG. 4B. In the case of the middle radius.

  As a result, the torsion angle θ3 of the pinch roller spring 24 is slightly smaller (smaller) than the angle θ1 in FIG. 4A, so that the force for pressing the pinch roller 22 against the paper feed roller 21 is slightly smaller ( Smaller). According to such a configuration, when a recording sheet thicker than usual is sandwiched between the paper feed roller 21 and the pinch roller 22, the torsion angle of the pinch roller spring 24 becomes larger than usual, whereby Thus, it is possible to prevent the generated load on the pinch roller holder 23 from increasing. Therefore, the rotation load due to the axial loss of the paper feed roller 21 can be leveled, whether the recording paper has a normal thickness or a thick recording paper. When the lift cam shaft 58 makes one rotation through the above state, the pinch roller release mechanism and the pinch roller spring pressure adjusting mechanism return to the state shown in FIG.

  FIG. 5 is a partial side view schematically showing the operation of the PE sensor lever up / down mechanism. FIG. 5A shows a case where the PE sensor lever pressing cam 61 is at the initial position and the PE sensor lever (paper detection lever) 66 is in a free state. The PE sensor lever 66 is rotatably supported by pivotally supporting the PE sensor lever shaft 66 a by a bearing portion of the chassis 10. In the state of FIG. 5A, the PE sensor lever 66 is urged to the illustrated position by the action of the PE sensor lever spring 68, and the shield plate of the PE sensor lever 66 shields the PE sensor 67. In this state, when the recording sheet passes through the portion of the PE sensor lever 66, the PE sensor lever 66 rotates clockwise in FIG. 5, the PE sensor 67 enters the transmission state, and the presence of the recording sheet is detected. can do. In this light-shielded and transmitted state, the leading and trailing edges of the recording sheet can be detected.

  FIG. 5B is a partial side view schematically showing a state in which a PE sensor lever 66 as a paper detection lever is locked. 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 rotates in the direction of arrow b. In this state, the sheet detecting portion of the PE sensor lever 66 is hidden behind the pinch roller holder 23, and the recording sheet does not contact the PE sensor lever 66 even when the recording sheet is in the passing path. . Therefore, even if the recording sheet is conveyed in the direction of the arrow b in FIG. 2 in this state, the recording sheet does not hit the PE sensor lever 66 and jam.

  FIG. 6 is a partial side view schematically showing the operation of the paper passing guide up / down mechanism. FIG. 6A shows a case where the paper passing guide 70 as a guide member is in an up state. In FIG. 6A, the paper passing guide 70 is normally urged in a direction in which it is lifted by the paper passing guide spring 71, and hits a stopper (not shown) to determine a position (elevated position, up position). . When the recording sheet fed from the main ASF passes by the action of the sheet passing guide spring 71 as the elastic member, the sheet passing guide 70 keeps this posture (up state). However, when a force larger than usual is applied, the sheet passing guide 70 is configured to be able to lower (become a down state) against the spring force of the sheet passing guide spring 71.

  FIG. 6B shows a case where the paper passing guide 70 is in the down state. In FIG. 6B, the paper passing guide pressing cam 65 fixed to the lift cam shaft 58 rotates in the direction of arrow a in FIG. A certain paper passing guide cam follower portion 70a is contacted and gradually pressed. Thus, the paper passing guide 70 is rotated in the direction of arrow b in FIG. In this state, the portion of the paper passing guide 70 facing the paper passing path is substantially horizontal, and the paper passing path is almost completely straight. As a result, even when the paper is conveyed in the direction of arrow b from the paper feed roller 21 in FIG. 2, the recording paper is conveyed horizontally, and the already recorded portion of the surface of the recording paper becomes It is no longer pressed upward.

  FIG. 7 is a schematic perspective view showing the carriage up-down mechanism. In FIG. 7, reference numeral 14a denotes a right guide shaft cam attached to the guide shaft 14, 14b denotes a left guide shaft cam attached to the guide shaft 14, and 53 connects a lift cam gear 52 and an integral gear of the right guide shaft cam 14a. It is a cam idler gear. As shown in FIG. 1, the guide shaft 14 is supported on both side surfaces of the chassis 10, and a vertically long guide elongated hole (not shown) and the guide shaft 14 are fitted to each other. Can move freely, but the movement in the directions of arrows X and Y in FIG. 7 is restricted.

  In the 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, but when the cam idler gear 53 rotates, the right guide shaft cam 14a and When the left guide shaft cam 14b comes into contact with the guide slope 56, the guide shaft 14 is configured to move vertically while rotating.

  FIG. 8 is a partial side view schematically showing the operation of the carriage up-down mechanism. FIG. 8A shows a case where the carriage 13 is at the first carriage position, which is the standard position. In this state, the guide shaft 14 is abutted and positioned at the lower limit of the guide elongated hole 57 of the chassis 10, and the guide shaft cam 14a and the guide slope 56 are not in contact.

  FIG. 8B shows a state in which the carriage 13 has moved to a slightly higher second carriage position. When the lift cam shaft 58 rotates to rotate the lift cam gear 52 fixed to the lift cam shaft 58, the guide shaft cam 14c rotates via the cam idler gear 53 that has engaged with the lift cam gear 52. By the rotation of the guide shaft cam 14c, the carriage 13 guided and supported by the guide shaft 14 moves (rises) from the first carriage position to the second carriage position. At this time, if the lift cam gear 52 and the guide shaft cam gear 14c have the same number of teeth, the lift cam shaft 58 and the guide shaft 14 rotate in the same direction at substantially the same angle. 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 fixed rotating shafts, whereas the guide shaft cam gear 14c has the guide shaft 14 itself, which is the rotating shaft, that moves up and down. This is because the distance fluctuates.

  Thus, when the lift cam shaft 58 rotates in the direction of the arrow a in FIG. 8, the guide shaft 14 also rotates in the direction of the arrow b in FIG. By this rotation, the guide shaft cams 14a and 14b abut against the fixed guide slope 56, and the moving direction of the guide shaft 14 is restricted only in the vertical direction by the guide long hole 57 of the chassis 10 as described above. The guide shaft 14 moves to the second carriage position. The second carriage position is preferably set when the recording paper greatly deforms and the recording paper comes into contact with the recording head 11 at the first carriage position.

  FIG. 8C shows a case where the carriage 13 is at the highest third carriage position. As the lift cam shaft 58 rotates further than the second carriage position, the radius of the cam surfaces of the guide shaft cams 14a and 14b increases, and the guide shaft 14 moves to a higher position. This third carriage position is suitable when a recording medium (recording paper) having a thickness larger than usual is used. The above is a detailed description of the five mechanisms, namely, the pinch roller release mechanism, the PE sensor lever release mechanism, the pinch roller spring pressure adjustment mechanism, and the paper passing guide up / down mechanism.

  FIG. 9 is a schematic perspective view showing a drive mechanism of the lift cam shaft. Next, a drive mechanism of the lift cam shaft 58 will be described. In the present embodiment, the drive source of the lift cam shaft 58 controls the rotation direction and the amount of rotation of the ASF motor 46 that drives the main ASF 37 to operate the main ASF (automatic paper feed unit) 37 as appropriate, Or operating. In FIG. 9, reference numeral 46 denotes an ASF motor serving as a driving source (an upper half is cut out to show gears); 47, an ASF pendulum arm located at the next stage of a gear attached to the ASF motor 46; An ASF sun gear attached to the center of the arm 47, 49 is an ASF planetary gear attached to the end of the ASF pendulum arm 47 and engaged with the ASF sun gear 48, 63 is a pendulum lock cam fixed to the lift cam shaft 58, 64 is This is a pendulum lock lever that swings by acting on the pendulum lock cam 63.

  As described above, the driving force transmission direction is determined by the rotation direction of the ASF motor 46. For the purpose of 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 engaged with a predetermined frictional force, the ASF pendulum arm 47 swings in the rotation direction of the ASF sun gear 48 (the direction of the arrow b in FIG. 9). Then, the ASF planetary gear 49 is engaged with the next stage lift input gear 50. Thus, 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 in FIG. 9, the driving force to the gear train for driving the main ASF 37 as the automatic sheet feeding unit is cut off. .

  Conversely, when driving the main ASF 37 as an automatic sheet feeding section, the ASF motor 46 is rotated in the direction opposite to the arrow a in FIG. Swings in the direction opposite to the arrow b. Thereby, the engagement between the ASF planetary gear 49 and the lift input gear 50 is released, and another ASF planetary gear 49 provided on the ASF pendulum arm 47 is engaged with the gear train on the main ASF 37 side, and the main ASF 37 is driven. Is done. In the present embodiment, a so-called stepping motor is used as the ASF motor 46, which 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.

  Here, when the planetary gear mechanism is used for transmitting the driving force, if the driven side has a negative load, the pendulum lock lever 64 moves to disengage the gear, and the driven side becomes the driving source. There is a possibility that the phase will advance more than before, that is, a so-called advance will occur. In order to prevent this, in this embodiment, a pendulum lock cam 63 and a pendulum lock lever 64 are provided. 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. 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 synchronously.

  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 in FIG. 9, and the lock of the ASF pendulum arm 47 is released, so that the ASF motor 46 can be rotated in the reverse direction. For example, the state returns to a state where the drive can be transmitted to the main ASF side. 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 adjustment of the pressure of the pinch roller spring 24, the vertical movement of the sheet passing guide 70, and the vertical movement of the carriage 13. Hereinafter, the five types of movable mechanisms are collectively referred to as a 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 the 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 at 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 (FIG. 4) is in pressure contact with normal pressure. The guide 70 is in the up state, and the carriage 13 is at the first carriage position.

  The state shown in FIG. 10A is a position used for a recording operation using a normal recording sheet or a registration after the recording sheet is inverted in the automatic duplex unit 2. The carriage 13 is movably guided and supported along a guide shaft 14. The carriage 13 is moved up and down along a guide slot 57 formed in the chassis 10 so as to move the carriage 13 up and down. It is configured.

  FIG. 10B shows a case where the lift mechanism is at 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 passing guide 70 is up. In this state, the carriage 13 is at the second carriage position. The only difference is that the height position of the carriage 13 is different from the first position of the lift mechanism. This state is a position used for preventing the recording paper from being greatly deformed and rubbing between the recording paper and the recording head 11 and when using a slightly thick recording paper.

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

  FIG. 10D shows a case where the lift mechanism is at the fourth position. In this state, the pinch roller 22 is pressed against the paper feed roller 21, the PE sensor lever 66 is retracted upward and locked (locked), and the pinch roller spring 24 (FIG. 4) is slightly weak. The paper passing guide 70 is in a state of being lowered, and the carriage 13 is at the highest third carriage position. This state is different from the third position of the lift mechanism in that the pinch roller 22 is returned to the pressed state, and the pinch roller spring 24 is pressed with a slightly weak pressure. This state is a position used when the recording paper is conveyed toward the automatic double-sided unit 2 after the recording paper is redrawn at the time of automatic double-sided recording or when recording is performed using a thick recording medium. is there.

  In the present embodiment, in consideration of the operation of the recording apparatus, the mechanism is simplified by limiting the positions to four types of lift mechanisms as shown in FIGS. 10A to 10D as an example. Is becoming That is, during one rotation of the lift cam shaft 58, the position is circulated in the order of the first position → the second position → the third position → the fourth position → the first position to change the position. The gist of the present invention is not limited to this, and each mechanical element may be configured to operate independently and appropriately. 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 does not matter. Further, even if the paper feed guide 70 is horizontal due to the arrangement of the main ASF 37 or the like, a vertical mechanism of the paper feed guide 70 may be omitted as long as the mechanism can guide the leading end of the recording paper to the nip portion of the paper feed roller 21 successfully. .

  FIG. 11 is a timing chart showing an operation state of the lift mechanism. In order to make the contents described in FIGS. 4 to 10 easier to understand, a description will be given again using the timing chart of FIG. The horizontal axis in FIG. 11 shows the angle of the lift cam shaft 58 in a range of 360 degrees, and the vertical axis shows each mechanism element and its position. 11, 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 (FIG. 3), and the rotation angle of the ASF motor 46 (FIG. 21) is controlled. By doing so, a plurality of mechanisms can be operated simultaneously. The above is the description of the operation of the lift mechanism.

  FIG. 12 is a schematic side view for explaining a process of drawing the recording paper again into the nip portion of the paper feed roller 21 after the recording on the front surface (front surface, first surface) of the recording paper. . Next, with reference to FIG. 12, how the automatic double-sided recording is performed on the recording paper will be specifically described. FIG. 12A shows that the recording on the front surface (front surface, first surface) of the recording paper 4 as the recording medium is completed, and the recording paper 4 is moved to the first discharge roller 30 and the first spur. The state in which the sheet is nipped by the row 32, the second discharge roller 31, and the second spur row 33 is shown. The first spur train 32 and the second spur train 33 are constituted by rotating bodies which are pressed by the corresponding discharge rollers and are driven to rotate. At this time, the lift mechanism is in the first position or the second position. As described above, if the recording paper 4 is advanced to this state and recording is performed, the discharge port row (discharge nozzle row) of the recording head 11 can face the rear end portion of the recording paper 4 as much as possible. 4, it is possible to record without making a bottom margin.

  Next, the lift mechanism is shifted to a third position as shown in FIG. 12B, and a large gap is provided between the pinch roller 22 and the paper feed roller 21 by a predetermined amount, so that Make it easy to retract, even if the edges are slightly wavy or curled up. At this time, since the pinch roller holder 23 and the carriage 13 do not interfere with each other, the carriage 13 may be at any position in the main scanning direction.

  12B, the recording paper 4 is conveyed in the direction of the arrow b in FIG. 2 by rotating the first discharge roller 30 in the direction of the arrow from the state of FIG. Conveying the recording paper 4 in this direction is referred to as back feed), moving the recording paper 4 to a position below the pinch roller 22 and stopping there. The reason why the printing is stopped in this state is that the printing apparatus of the present embodiment employs a wet ink jet printing method. That is, the recorded surface (the upper surface in FIG. 12) of the recording paper 4 is wet with ink immediately after the recording operation, and if the pinch roller 22 and the paper feed roller 21 are immediately pressed against each other, the pinch roller 22 is pressed. This is because there is a possibility that the ink is transferred to the recording paper 4 again, and the recording paper 4 is stained.

  Whether or not the ink is transferred to the pinch roller 22, in other words, whether or not the ink that has been hit on the recording paper 4 is dry depends on various conditions. That is, the type of recording paper, the type of ink used, the method of overprinting the used ink, the amount of ink used per unit area (for example, the density of the recorded data per unit area), The conditions include temperature, humidity of the environment in which the recording operation is being performed, and gas flow rate of the environment in which the recording operation is being performed. In general, if a recording paper having an ink receiving layer on the surface and capable of guiding the ink to the inside quickly is used, the ink is easily dried quickly. In addition, if an ink such as a dye, which has small ink particles and easily penetrates into the recording paper, is used, the ink easily dries quickly. In addition, if an ink system is used in which a chemically reactive ink is used and the ink system is solidified by being over-punched on the surface of the recording paper, it is easy to dry quickly.

  In addition, if the amount of ink to be ejected per unit area is reduced, it is easy to dry quickly. In addition, if the temperature of the environment in which the recording operation is being performed is increased, drying is quick and easy. Also, if the humidity of the environment in which the recording operation is being performed is reduced, drying is quick and easy. Further, if the flow velocity of the gas in the environment where the recording operation is being performed is increased, the gas is easily dried quickly. As described above, the necessary drying time is determined by several conditions. Therefore, in the present embodiment, the general use conditions (general recording paper, general recording paper, general A configuration is used in which the drying time required when recording is performed in a recording operation environment is specified as a standard value, and the drying time is varied under predictable conditions.

  This predictable condition is the amount of ink ejected per unit area. However, if the environmental temperature detecting means, the environmental humidity detecting means, the environmental wind speed detecting means, and the like are used in combination, the drying standby time can be predicted more finely. It is also possible. For example, data received from the host device 308 (FIG. 21) is stored in the RAM 312 (FIG. 21), the amount of ink ejected per unit area is calculated, and the maximum value and a predetermined value described in the ROM 311 (FIG. 21) are calculated. A method of determining the drying standby time by comparing with a threshold value can be adopted. In other words, when the maximum value of the amount of ink discharged per unit area is large, the drying standby time is lengthened, and when the maximum value is small, the drying standby time is shortened, thereby optimizing the drying standby time according to the recording pattern. be able to.

  Also, the type of ink used for recording is a dye-based ink or a pigment-based ink, but the drying standby time differs depending on whether it is a pigment-based ink.However, in the case of a dye ink, the drying standby time is shortened because it is easy to dry, In the case of the pigment ink, the drying standby time is lengthened because it is difficult to dry. When the ambient temperature is high, drying is easy, so the drying standby time is shortened. When the ambient temperature is low, drying is difficult, so the drying standby time is lengthened. When the ambient humidity is high, drying is difficult, so the drying standby time is lengthened. When the ambient humidity is low, drying is easy, so the drying standby time is shortened. Further, in the case of a recording paper having an ink receiving layer on the surface and taking in the ejected ink into the paper immediately, the surface of the recording paper is easy to dry. In the case of a recording sheet having a strong water-based property, it is difficult to dry the recording sheet.

  Although the drying standby may be performed at the position (a) in FIG. 12, the reason why it is preferable that the recording paper 4 is back-fed to the position shown in FIG. This is largely due to the deformation of the recording paper 4. That is, when recording is performed on a recording sheet by a wet ink-jet process, the recording sheet absorbs moisture, so that the fibers of the recording sheet expand and the recording sheet may expand. Depending on the pattern to be recorded, there are cases where a portion that extends on the paper and a portion that does not extend are formed, and in such a case, the unevenness of the paper surface is particularly markedly formed. The amount of unevenness mainly depends on the time from when the recording paper starts absorbing moisture, and the amount of unevenness increases with time, and converges to a predetermined amount of deformation.

  If the amount of deformation of the paper edge increases over time, the paper edge may interfere with the pinch roller 22 and cause a jam even if the pinch roller 22 is released away from the paper feed roller 21. is there. In order to prevent this, after the recording is completed, the recording paper is moved back to below the pinch roller 22 by back-feeding before the unevenness of the recording paper becomes large. For the above reasons, the rear end of the front surface of the recording paper 4 is back-fed to the position shown in FIG. 12B, and the recording paper 4 waits for the recorded portion to dry. The gap between the paper feed roller 21 and the pinch roller 22 at the time of separation is set to be larger than the deformation amount of the recording paper after the first surface (front surface) recording of the recording paper.

  FIG. 12C shows a state in which the recording paper 4 is being conveyed toward the automatic duplex unit 2. When the recorded portion of the recording paper 4 dries and the ink does not transfer to the pinch roller 22 even when pressed against the pinch roller 22, the lift mechanism is moved to the fourth position as shown in FIG. Then, the recording paper 4 is nipped by the pinch roller 22 and the paper feed roller 21. In this state, the paper feed roller 21 is driven to feed back the recording paper 4. At this time, since the PE sensor lever 66 is rotated upward and locked, it is unlikely that the tip of the PE sensor lever 66 cuts into the recording paper 4 or rubs off the recorded portion. Absent.

  Further, since the paper passing guide 70 is in the down state, the paper passing surface is substantially horizontal, and the recording paper 4 can be transported straight toward the automatic duplex unit 2. In the present embodiment, the normal paper passing guide 70 is basically in the up state, but the gist of the present invention is not limited to this, and the normal state of the paper passing guide may be in the down state. That is, the normal standby state may be set as the third position or the fourth position of the lift mechanism, and the lift mechanism may be configured to move to the first position during the sheet feeding operation from the main ASF 37. With this configuration, it is possible to smoothly insert the recording medium having high rigidity from the discharge roller side. The above is the description of the process of transporting the recording paper 4 to the automatic duplex unit 2 from the end of the front surface recording.

  FIG. 13 is a schematic side cross-sectional view showing a paper passing path of the automatic duplex unit 2 as a sheet reversing unit or an automatic reversing unit and a state of installation of a conveying roller. Next, with reference to FIG. 13, a recording paper transporting mode inside the automatic duplex unit 2 will be described. In FIG. 13, reference numeral 101 denotes a double-sided unit frame constituting a part of the structure of the automatic double-sided unit 2 and the sheet conveyance path, 102 an inner guide fixed inside the double-sided unit frame 101 and constituting a part of the sheet conveyance path, Reference numeral 103 denotes a rear cover which is freely openable and closable behind the double-sided unit frame 101 and constitutes a part of a sheet conveyance path. Is a double-sided roller rubber A, which is a rubber part of the double-sided roller A 108, and 111 is a double-sided roller rubber B, which is a rubber part of a double-sided roller B 109.

  When the recording paper 4 is conveyed to the automatic duplex unit 2 from the state shown in FIG. 12C, the outlet flap 106 is urged to the position shown in FIG. Roads are uniquely determined. Therefore, the recording paper 4 advances in the direction of arrow a in FIG. Next, the recording paper 4 hits the switching flap 104 which is a movable flap. In the case of recording paper 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. Therefore, the recording paper 4 advances along a paper passing path between the switching flap 104 and the duplex unit frame 101. The recorded surface (front surface) of the recording paper 4 directly contacts the double-sided roller rubber B111 of the double-sided roller B109, and the unrecorded surface (backside) contacts the double-sided pinch roller B113 made of a high-lubricity polymer resin. , Are sandwiched between the two.

  At this time, since the peripheral speeds of the two-sided roller A108 and the two-sided roller B109 and the paper feed roller 21 are set to rotate substantially the same by a driving mechanism described later, the sliding between the recording sheet 4 and the two-sided roller B109 is performed. Are transported without generating the Further, since the peripheral speeds are substantially the same, there is no possibility that the recording paper 4 is slackened or a tension is applied. When the traveling direction is changed by the double-sided roller B109, the recording sheet 4 advances along the rear cover 103, and is similarly sandwiched between the double-sided roller rubber A110 of the double-sided roller A108 and the double-sided pinch roller A112.

  Again, the traveling direction is changed by the double-sided roller A108, and the recording paper 4 is transported in the direction of the arrow b in FIG. The two-sided roller A108 and the two-sided roller B109 constitute a reversing roller for reversing the front and back or the transport direction of the recording medium 4. When the recording sheet 4 proceeds as it is, the leading end of the recording sheet 4 comes into contact with the exit flap 106. Since the exit flap 106 is urged by the exit flap spring 107 having a very weak load, the recording sheet 4 itself pushes the exit flap 106 out of the automatic duplex unit 2. When the leading end of the recording sheet 4 in the traveling direction exits the exit flap 106, the paper passing path length in the automatic duplex unit 2 is set so that the trailing end of the recording sheet 4 in the traveling direction already passes below the exit flap 106. Since it is set, the leading end and the trailing end of the recording paper 4 themselves do not rub against each other.

  Although a detailed flowchart will be described later, when recording on the surface of the recording paper 4, the length of the recording paper can be measured by the PE sensor lever 66. A recording sheet shorter than the distance or the distance from the two-sided roller A 108 to the paper feed roller 21 or a recording sheet longer than the distance from the exit flap 106 of the automatic duplex unit 2 and returning to the exit flap 106 is inserted. In such a case, a warning is issued when the recording on the front side is completed, and the recording sheet 4 is discharged without being transported to the automatic duplex unit 2.

  Here, the reason why the recording surface of the recording sheet 4 is conveyed with the double-sided roller rubber A110 and the double-sided roller rubber B111 side will be described. The double-sided roller rubber A110 and the double-sided roller rubber B111 are on the driving side, and the double-sided pinch roller A112 and the double-sided pinch roller B113 are on the driven side. 4 will be rotated by the frictional force. At this time, the axial loss of the rotating shaft supporting the double-sided pinch roller A112 and the double-sided pinch roller B113 may be sufficiently small. There is a possibility that slippage occurs with the roller B113. The portion recorded on the recording paper 4 is dry to the extent that the ink is not transferred due to contact with the roller, but if rubbed, the ink may peel off from the surface of the recording paper 4 There is also.

  If the recorded surface of the recording paper 4 is in contact with the double-sided pinch roller A112 or the double-sided pinch roller B113 and slips between these rollers, the ink on the recorded surface may peel off. There is. In order to prevent this, as in this embodiment, the drive side member is brought into contact with the recorded surface (front side), and the driven member is brought into contact with the unrecorded surface (back side). I have. Further, another reason for arrangement is as follows. That is, the driving-side double-sided roller A108 or the double-sided roller B109 cannot be reduced to a diameter smaller than a certain value because there is a restriction due to the bending radius of the recording sheet 4, but the double-sided pinch roller A112 and the double-sided pinch roller B113 have a small diameter. In order to design the automatic double-sided unit 2 compactly, the double-sided pinch roller A112 and the double-sided pinch roller B113 are often designed to have a small diameter.

  In addition, although ink is not basically transferred from the recorded surface of the recording paper 4 to the roller side, the ink is transferred little by little, and the roller contacting the recorded surface may be gradually stained with ink. . In the case of a roller having a small diameter, the frequency at which the outer periphery of the roller comes into contact with the recording paper increases, and the speed at which the roller is soiled is higher than that of a roller having a large diameter. It can be said. As described above, in the present embodiment, from the viewpoint of miniaturization of the apparatus and contamination of the rollers, the two-sided roller A108 and the double-sided roller B109 having a large diameter are placed on the side that comes into contact with the recorded surface (front surface) of the recording sheet. And

  Furthermore, another reason for the arrangement is as follows. That is, when the paper is nipped and transported by a pair of rollers driven on one side, the driving side is made of a material having a high friction coefficient and the driven side is made of a material having a low friction coefficient in order to make the transport amount accurate. In order to increase the area of the part (nip area), one of them is often made of an elastic material. Normally, a rubber material (rubber-like elastic material) which provides a high coefficient of friction at a relatively low cost and has a high elasticity is usually used as the drive side material. Further, in order to increase the conveying force, a means for polishing the surface of rubbers including an elastomer or the like and intentionally providing fine irregularities on the polished eyes 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 rubber with minute irregularities and the surface of a smooth polymer resin, when they are brought into contact with the recorded surface of the recording paper, ink stains adhere to both, In the case of rubbers, the dirt is retained by the unevenness, so that the dirt is less likely to be transferred to the recording paper again, whereas the dirt may be peeled off and retransferred to the recording paper with a smooth polymer resin. Therefore, it can be said that it is more advantageous to bring the rubbers into contact with the recorded surface of the recording paper. As described above, in the present embodiment, a roller made of a rubber material is arranged on the side that comes into contact with the recorded surface (front side, front side) of the recording paper, and the unrecorded side (back side, back side) A roller made of a polymer resin material is disposed on the side that comes into contact with the roller. The above is the description of the reversing operation for recording both sides of a normal recording sheet.

  Next, an operation of the automatic double-sided unit 2 in a case where recording is to be performed on a recording medium having high rigidity without performing automatic double-sided recording will be described. The recording medium having high rigidity is, for example, a case where thick paper having a thickness of 2 mm to 3 mm or a recording medium having a disk shape or a deformed shape is placed on a predetermined tray and conveyed. Since such a recording medium has a high rigidity, it cannot be curved enough to follow the diameter of the double-sided roller of the automatic double-sided unit 2, so that automatic double-sided recording cannot be performed. There may be situations where it is desired to perform recording on such a recording medium in the state described above. When the rigidity of the recording medium is high, the paper cannot be fed using the main ASF 37. In this case, in order to use a straight paper passing path, the paper is moved from the paper discharging roller side to the paper feeding roller 21 side. The recording medium is fed toward the recording medium. The operation of the automatic duplex 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 double-sided recording is performed using the above-described ordinary recording paper (recording medium). At this time, the switching flap spring 105 keeps urging the switching flap 104 against the stopper against the pressing force of the recording paper 4, so that the recording paper 4 is guided (guided) along the paper passing path for reversing. .

  FIG. 14B shows a state in which a recording medium having high rigidity (including recording paper) is used. When the recording medium 4 having high rigidity is conveyed to the automatic duplex unit 2, the recording medium passes under the outlet flap 106 and contacts the switching flap 104. The switching flap spring 105 is set to such a spring load that when the recording medium having high rigidity is inserted and the switching flap 104 is pressed, the switching flap 104 is retracted by the pressing force. As the medium advances, it rotates in the counterclockwise direction (arrow direction) in FIG. 14B and retracts. Therefore, the recording medium having high rigidity is guided to the retreat path 131 which is a second paper passing path provided between the two-sided roller A108 and the two-sided roller B109. Since holes (through holes, openings) are formed in the portion corresponding to the retreat path 131 of the rear cover 103, even when a long and rigid recording medium is used, the recording medium interferes with the automatic duplex unit 2 and is conveyed. Is not limited.

  The gist of the present invention is not limited to the above-described configuration described with reference to FIG. That is, in implementing the present invention, it is not essential to provide the retreat path 131 between the upper and lower two-sided rollers 108 and 109, and the following configuration is also possible. FIG. 22 is a schematic side sectional view showing an automatic double-sided unit configured by disposing a large-diameter double-sided roller above a substantially horizontal path. In FIG. 22, the switching flap 104 is urged to a position shown in FIG. 22 by a switching flap spring (not shown), and the spring force (pressing force) of the switching flap spring when the recording paper having high rigidity comes into contact with the switching flap spring is pressed. Is set so that the switching flap 104 can rotate. Also in FIG. 22, the portions corresponding to the respective portions in FIGS. 13 and 14 are denoted by the same reference numerals, and the details thereof will be referred to the above description, and the detailed description will be omitted here.

  Therefore, in the case of a recording sheet having low rigidity, the recording sheet advances in the direction of arrow a in FIG. 22 by rotation of the double-sided roller A108 in the direction of arrow c in FIG. In such a case, the switching flap 104 is pushed away and proceeds to the evacuation path 131 in the direction of arrow b in FIG. As a result, even when a long and highly rigid recording medium is used, the conveyance is not restricted by interfering with the automatic duplex unit. As described above, in the automatic duplex unit according to the present embodiment, it is also possible to perform single-side recording on a recording medium (including recording paper) having high rigidity and without curving without removing the automatic duplex unit. The above is an explanation of the automatic duplex unit 2 having two types of paper passing paths.

  Next, the driving mechanism of the rollers of the automatic duplex unit 2 will be described. FIG. 15 is a schematic side sectional view showing a configuration of a driving mechanism of rollers of the automatic double-sided unit 2 when one embodiment (FIG. 1) of the recording apparatus to which the present invention is applied is viewed from a side opposite to FIG. . In FIG. 15, reference numeral 115 denotes a double-sided transmission gear train for transmitting power from the LF motor 26 to the double-sided sun gear 116, 116 denotes a double-sided sun gear at the center of a double-sided pendulum arm, and 117 denotes a swingable centered on the double-sided sun gear 116 as a rotation center. The double-sided pendulum arm 118 is a double-sided planetary gear B rotatably mounted on the double-sided pendulum arm 116 and engaged with the double-sided sun gear 116.

  In FIG. 15, reference numeral 120 denotes a spiral groove gear engaged with the double-sided sun gear 116 via an idler; 121, an inverted delay gear A engaged with a double-sided planetary gear; 122, inverted delay gears B, 123 coaxial with the inverted delay gear A121; Is a reversing delay gear spring for giving a relative urging force between the reversing delay gear A121 and the reversing delay gear B122; 124 is a double-sided roller idler gear connecting two two-sided roller gears; 125 is a two-sided roller gear fixed to the two-sided roller A108 A and 126 are double-sided roller gears B fixed to the double-sided roller B109, 127 is a stop arm that swings in contact with the groove of the spiral groove gear 120, 128 is a stop arm spring that centers the stop arm 127, and 132 is a double-sided pendulum arm Both sides attached to 117 Riko arm spring, it is.

  As described above, in the present embodiment, the driving force of the automatic duplex unit 2 is obtained from the LF motor 26 that drives the paper feed roller 21. With such a configuration, when the paper feed roller 21 and the double-sided roller A 108 or the double-sided roller B 109 cooperate to convey the recording paper, the timing of starting and stopping and the recording paper conveyance speed are almost completely reduced. Synchronization is possible, and it is preferable to adopt such a configuration. The driving force from the LF motor 26 is transmitted to the double-sided sun gear 116 via the double-sided transmission gear train 115. A swingable double-sided pendulum arm 117 is attached to the double-sided sun gear 116, and a double-sided planetary gear A 118 and a double-sided planetary gear B 119 are attached to the double-sided pendulum arm 117.

  Since a suitable frictional force acts between the double-sided sun gear 116 and the double-sided pendulum arm 117, the double-sided pendulum arm 117 swings according to the rotation direction of the double-sided sun gear 116. Here, assuming that the direction in which the paper feed roller 21 rotates the LF motor 26 in the direction in which the recording paper is transported in the paper discharge direction is the forward direction, and the direction in which the recording paper is transported to the automatic duplex unit 2 is the reverse direction, LF When the 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 basically swings in the direction of arrow a in FIG.

  Then, the double-sided planetary gear A118 engages with the double-sided roller idler gear 124 to rotate the double-sided roller idler gear 124. With the rotation of the double-sided roller idler gear 124, the double-sided roller gear A125 rotates in the direction of the arrow c in FIG. 15, and the double-sided roller gear B126 similarly rotates in the direction of the arrow d in FIG. The directions indicated by arrows c and d in FIG. 15 are directions in which the double-sided roller A108 and the double-sided roller B109 respectively convey the recording paper in the 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. With the rotation of the double-sided sun gear 116, the double-sided pendulum arm 117 also basically swings in the direction of arrow b in FIG. Then, the double-sided planetary gear B119 is engaged with the reverse delay gear A121. The reversing delay gear A121 and the reversing delay gear B122 have protrusions projecting from opposing thrust surfaces. When the reversal delay gear B122 is fixed and considered, when the reversing delay gear A121 makes one rotation, the clutch of the protrusions meshes with each other. Playing a role.

  Before the double-sided planetary gear B119 is engaged with the reverse delay gear A121, the protrusion between the reverse delay gear A121 and the reverse delay gear B122 is urged by the reverse delay gear spring 123 in a direction in which the protrusions are separated from each other. After approximately one rotation from the start of the rotation of the delay gear A121, the inversion delay gear B122 starts to rotate. The period from the start of rotation of the LF motor 26 in the reverse rotation direction to the start of rotation of the reverse delay gear B122 is a delay period in which the double-sided roller A108 and the double-sided roller B109 are stopped.

  When the reverse delay gear B122 rotates, the double-sided roller gear A is rotated in the direction of arrow c in FIG. 15 and the double-sided roller gear B is rotated in the direction of arrow d in FIG. 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 two-sided roller A108 and the two-sided roller B109 can always be rotated in the recording paper transport direction 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, and a cam having a spiral groove with an endless track on the innermost and outermost surfaces is formed on one end surface. In this embodiment, the spiral groove gear 120 is directly connected to the double-sided sun gear 116 via the idler gear, and therefore, rotates in the same direction as the double-sided sun gear 116. 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 with the rotation of the spiral groove gear 120. For example, when the spiral groove gear 120 rotates in the direction of arrow e in FIG. 15, the follower pin 127a is pulled into the inner periphery, and the stop arm 127 swings in the direction of arrow g in FIG. Even if the spiral groove gear 120 keeps rotating in the direction of arrow e in FIG. 15, the stop arm 127 stops at a predetermined position because the follower pin 127a enters the innermost endless track.

  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, and 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 arrow f in FIG. 15, the follower pin 127a enters the outermost endless track, and the stop arm 127 stops at a predetermined position. In addition, when the rotation direction of the spiral groove gear 120 changes, a stop arm that centers around the center of the movement range of the stop arm 127 so that the spiral groove can smoothly move from the outermost and innermost endless tracks to the spiral groove. A spring 128 is attached to the stop arm 127.

  The stop arm 127 performing such an operation acts on the double-sided pendulum arm spring 132 attached to the double-sided pendulum arm 117. The double-sided pendulum arm spring 132 is an elastic member attached to the double-sided pendulum arm 117 and extending in the direction of the stop arm 127. The tip of the double-sided pendulum arm spring 132 is always located closer to the center of the spiral groove gear 120 than the stop arm 127 is.

  With such a positional relationship, the following operation is exerted 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 paper 4 to the automatic double-sided unit 2 and turns over the recording paper 4 and returns to the paper feed roller 21, Thus, the stop arm 127 is rotating on the outermost endless track. Thereafter, when the LF motor 26 is rotated in the forward direction to perform recording on the back surface, the stop arm 127 moves toward the inner periphery of the spiral groove gear 120. When the LF motor 26 is rotating in the forward direction, the double-sided pendulum arm 117 swings in the direction of arrow a in FIG. It contacts the double-sided pendulum arm spring 132.

  When the LF motor 26 further rotates in the forward direction, the stop arm 127 moves further inward and elastically deforms the double-sided pendulum arm spring 132, so that the double-sided pendulum arm 117 is driven by the double-sided planetary gear A118 and the double-sided roller idler gear 124. The double-sided pendulum arm 117 is balanced by a force acting in the pressure angle direction when the tooth surfaces mesh with each other, a force for swinging the double-sided pendulum arm 117 in the direction of arrow a in FIG. Will be determined. In the case of the present embodiment, since the repulsive force of the double-sided pendulum arm spring 132 is set to be small, the double-sided pendulum arm spring 132 is elastically deformed even when the stop arm 127 is located at the innermost track. The power transmission between the two-sided planetary gear A 118 and the two-sided roller idler gear 124 is continued.

  Even when the operation of the LF motor 26 is intermittently driven and repeatedly stopped and rotated, the tooth surfaces of the double-sided planetary gear A118 and the double-sided roller idler gear 124 are still overlapped. Will not come off. However, when the recording on the back surface of the recording paper 4 is completed and the transmission of the drive to the automatic duplex unit 2 becomes unnecessary, it is preferable to cut off the drive from the viewpoint of reducing the load on the LF motor 26. Therefore, when it is desired to cut off the drive transmission, the following means is implemented.

  That is, the LF motor 26 is slightly rotated in the reverse direction while the stop arm 127 is in the innermost endless track and the double-sided pendulum arm spring 132 is elastically deformed. The double-sided pendulum arm 117 is about to rotate in the direction of arrow b in FIG. 15 due to the repulsive force of the double-sided pendulum arm spring 132 from the state where the tooth surfaces of the double-sided planetary gear A 118 and the double-sided roller idler gear 124 are stopped. 15, the double-sided pendulum arm 117 rotates at a stretch in the direction of arrow b in FIG.

  Once the double-sided pendulum arm 117 rotates in the direction of the arrow b in FIG. 15, the elastically deformed double-sided pendulum arm spring 132 returns to its original shape, so that even if the LF motor 26 is rotated in the forward direction, Since the double-sided pendulum arm spring 132 and the stop arm 127 interfere with each other, the double-sided pendulum arm 117 cannot swing to the position where the double-sided planetary gear A 118 and the double-sided roller idler gear 124 mesh. Therefore, from this state, the driving force is not transmitted to the double-sided pendulum arm 117 and the subsequent parts in the automatic double-sided unit 2 unless the LF motor 26 rotates in the reverse direction by a predetermined amount. Driving up to the double-sided pendulum arm 117 merely rotates the gear train, so that the load applied to the LF motor 26 is very small, and there is almost no difference from the load without the automatic double-sided unit 2.

  When the LF motor 26 rotates in the reverse direction from the state where the stop arm 127 is on the innermost endless track, no action is exerted between the double-sided pendulum arm spring 132 and the stop arm 127. As described above, the drive can be transmitted to the inversion delay gear A121. The above is the schematic description of the roller driving mechanism of the automatic duplex unit 2.

  FIG. 16 is a schematic side sectional view for explaining the operation of the rollers driving mechanism of the automatic duplex unit 2 in FIG. 15, and FIG. 20 is a flowchart showing the operation sequence of automatic duplex recording. Next, the operation of the roller driving mechanism of the automatic duplex unit 2 and the operation of the automatic duplex recording will be described in detail with reference to the flowchart of FIG. In FIGS. 16 and 20, when the automatic double-sided recording is started, the recording paper 4 is fed in step S1. For example, the recording paper 4 is supplied to the paper feed roller 21 from the main cover 37 or the like. Next, in step S2, recording of the front surface (front surface) is performed. 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.

  FIG. 16A shows a state in which the LF motor 26 is rotating in the forward direction after the drive mechanism of the automatic duplex unit 2 is initialized. That is, this indicates a state such as during a front (front) recording operation during automatic double-sided recording or during a normal recording operation without using automatic double-sided recording. Since the follower pin 127a of the stop arm 127 is on the endless orbit of the innermost circumference of the spiral groove gear 120, when the double-sided pendulum arm 117 swings in the direction of arrow a in FIG. The driving force from the LF motor 26 is not transmitted to the double-sided roller gear A125 and the double-sided roller gear B126 because the double-sided planetary gear A118 cannot engage with the double-sided roller idler gear 124 because of the rotation. In this state, since the double-sided roller A108 or the double-sided roller B109, which has suffered axial loss due to the pressure of the double-sided pinch roller A112 or the double-sided pinch roller B113, does not rotate, the load received by the LF motor 26 is small.

  Next, in step S3, it is confirmed whether or not the trailing edge of the recording sheet has been detected by the PE sensor 67 at the time when the front side recording is completed. At this time, if the PE sensor 67 has still detected the presence of the recording paper 4, the rear end of the front surface of the recording paper 4 has not yet been detected. The rear end of the surface of the recording paper 4 passes through the PE sensor lever 66 and is moved to a position p2 where the recording paper 4 is further moved. Next, in step S5, the length of the recording paper 4 is calculated from the amount of transport of the recording paper 4 from when the PE sensor 67 detects the front end of the recording paper 4 to when the front end is detected. I do.

  As described above, when the length of the recording paper 4 is shorter than the predetermined length L1, the recording paper 4 does not reach the rollers during the conveyance from the paper feed roller 21 to the duplex roller B109 or the duplex roller A108 to the paper feed roller 21. Therefore, it is necessary to exclude from the automatic double-sided recording operation. If the length of the recording paper 4 is longer than the predetermined length L2, the recorded surfaces of the recording paper may intersect in the paper passing path from the paper feed roller 21 to the automatic duplex unit 2. Since it is not preferable, it is necessary to exclude the automatic double-sided recording operation. If it is determined under these conditions that the recording paper 4 is to be excluded from the automatic double-sided recording operation, the process proceeds to step S6, where the LF motor 26 is rotated in the forward direction, and the recording paper 4 is discharged as it is. If the condition is satisfied, the process proceeds to step S7, in which the lift mechanism is set to the third position and the pinch roller 22 is released (separated). The separation of the pinch roller 22 from the paper feed roller 21 is after the end of the first predetermined time or the third predetermined time after the end of the surface recording.

  Next, in step S8, it is confirmed whether or not the rear end of the front surface of the recording paper 4 has already been transported to the downstream side from the position p1 near the pinch roller 22. If the pinch roller 22 has already been fed to the downstream side, in step S9, the rear end of the front surface is set to p1 so that the pinch roller 22 is reliably sandwiched between the paper feed roller 21 and the pinch roller 22 when the pinch roller 22 is returned to the pressed state. LF motor 26 is rotated in the reverse direction until the feed is performed. The state of the roller driving mechanism at this time is the state shown in FIG. In addition, in steps S2 to S8, it is preferable that the operation is not stopped as much as possible, and as described above, step S9 is performed before the recording sheet 4 is deformed. When the rear end of the front surface is located on the upstream side of p1, the recording paper can be reliably nipped by pressing the pinch roller 22 as it is, and the process proceeds to step S10.

  FIG. 16B shows a state immediately after the rotation of the LF motor 26 in the reverse direction starts. That is, immediately after the back feed is started after the front side recording of the automatic double-sided recording is completed, or when the LF motor 26 is reversed for the purpose of adjusting the cue amount after the paper is fed from the main ASF 37. At this time, there is nothing to prevent the double-sided pendulum arm 117 from swinging in the direction of arrow b in FIG. 15, and the double-sided planetary gear B119 is engaged with the reverse delay gear A121. As a result, the reversing delay gear A121 starts rotating, but the driving force is not transmitted to the reversing delay gear B122 until the reversing delay gear B122 rotates substantially once, so the double-sided roller idler gear 124 does not rotate, and the double-sided roller A108 and the double-sided roller B109 do not rotate. Does not work.

  Therefore, even in this state, the load on the LF motor 26 is still small. Such a state is set because, when the recording paper 4 is back-fed during automatic duplex recording, there is a distance from the paper feed roller 21 to the duplex roller B109. This is because the two-sided roller B109 does not need to rotate until it reaches the roller B109. Further, as described above, this is to prevent the double-sided roller A108 or the double-sided roller B109 from rotating unnecessarily at the time of adjusting the cueing amount during normal recording.

  Next, in step S10, a time is provided for waiting for the recorded ink on the surface of the recording paper 4 to dry. Since the required drying time varies depending on several factors as described above, the drying standby time t1 (second predetermined time) can be a variable parameter. More specifically, t1 is determined in consideration of conditions such as the type of recording paper, the type of ink, the method of superimposing ink, the amount of ink per unit area, the environmental temperature, the environmental humidity, and the environmental wind speed. . The second predetermined time is longer than the first predetermined time. Next, in step S11, the lift mechanism is set to the fourth position. As a result, the recording paper 4 is again held between the paper feed roller 21 and the pinch roller 22.

  Next, a drying standby time t2 (fourth predetermined time) is provided in step S12. This may not be used when the drying standby time t1 is performed in step S10, and it is possible to set t2 = 0 and proceed to the next step. The time t2 is used, for example, when a recording operation is not performed at the rear end of the recording paper 4 and a margin is present. This is because there is no problem even if the roller 22 is controlled to be pressed. However, if the recording paper 4 is conveyed immediately after back-feeding, the ink before drying may be transferred to the pinch roller 22, so the drying standby time t2 may be used here. The fourth predetermined time is longer than the third predetermined time.

  Next, in step S13, the LF motor 26 is rotated in the reverse direction, and the recording paper is fed back by a predetermined amount x1. In this step, the recording paper 4 is conveyed to the automatic double-sided unit 2 and turned over. When this step is completed, the leading end of the back surface has returned slightly before the paper feed roller 21. The state of the roller driving mechanism so far is the state shown in FIG.

  FIG. 16C shows a state in which the LF motor 26 is further rotated in the reverse direction. That is, this is a state in which the recording paper 4 is back-fed and inverted by the automatic duplex unit 2. After the state of FIG. 16 (b), when the reversing delay gear 121 makes substantially one rotation, the protrusion of the reversing delay gear A121 that protrudes in the thrust direction engages with the protrusion of the reversing delay gear B122 provided opposite to the reversing delay gear B122. The delay gear A121 and the reverse delay gear B122 start rotating integrally. When the reversing delay gear B122 starts rotating, the reversing delay gear B122 is always in contact with the double-sided roller idler gear 124, so that the two-sided roller idler gear 124, the two-sided roller gear A125, and the two-sided roller gear B126 rotate. Thus, the double-sided roller A108 rotates in the direction of arrow c in FIG. 15, and the double-sided roller B109 rotates in the direction of arrow d in FIG.

  Next, a so-called registration operation when the front end of the back surface is held between the nip portion between the paper feed roller 21 and the pinch roller 22 will be described. First, in step S14, the control is switched depending on whether the recording sheet 4 currently used is a thin sheet having low rigidity or a thick sheet having high rigidity. The rigidity of the recording paper 4 may be determined according to the type of recording paper set by the user using a printer driver or the like, or may be determined using a detection unit that measures the thickness of the recording paper. Here, the reason why the control is divided into two is that the behavior when the recording paper 4 is bent to form a loop differs depending on the rigidity of the recording paper.

  First, the case of a thin recording sheet having relatively low rigidity will be described. FIG. 18 is a schematic cross-sectional side view showing the registration operation at the front end of the back surface when a thin recording paper is used. 20 and 18, the reverse rotation of the LF motor 26 in step S13 causes the paper to be reversed and transported as shown in FIG. When step S13 is completed, the leading end of the back surface of the recording paper has returned to the vicinity of the paper passing guide 70. If the recording paper is thin, the process proceeds to step S15. In step S15, the lift mechanism is operated to shift to the first position. Thereby, the paper passing guide 70 is raised.

  FIG. 18B shows a state in which step S15 has been completed. As described above, since the center of the pinch roller 22 is disposed on the first discharge roller 30 side with a slight offset with respect to the center of the paper feed roller 21, the nip between the paper feed roller 21 and the pinch roller 22 is provided. Part) has a slight angle with respect to the substantially horizontal line on which the recording paper 4 is conveyed. By returning the paper passing guide 70 to the raised position before the registration operation, it becomes possible to smoothly guide the leading end of the back surface of the recording paper 4 to the inclined nip portion. Next, in step S16, the LF motor 26 is rotated in the reverse direction, and the recording paper 4 is further conveyed toward the paper feed roller 21. Next, in step S17, the front end of the back surface of the recording paper 4 is detected by the PE sensor 67. If the back end can be detected, the process proceeds to step S18.

  Next, in step S18, the recording paper 4 is conveyed by a distance x2 slightly longer than the distance from the back end detection position by the PE sensor 67 to the paper feed roller 21. As a result, the leading end of the back surface of the recording paper 4 reaches the nip portion between the paper feed roller 21 and the pinch roller 22, and the recording paper 4 is bent by an extra amount to form a loop. FIG. 18C shows a state when step S18 is completed. Although the clearance in the height direction of the paper passing path is reduced by setting the paper passing guide 70 to the raised position, since the rigidity of the recording paper 4 is relatively low, a loop is easily formed and the paper is pushed. The leading end of the back surface of the recording paper 4 follows the nip portion between the paper feed roller 21 and the pinch roller 22 that continues to rotate in the reverse direction, becomes parallel to the paper feed roller 21, and the so-called registration operation is completed. Next, in step S19, the rotation direction of the LF motor 26 is changed to the forward direction rotation, the front end of the back side of the recording paper 4 is nipped by the nip portion, and is conveyed by a predetermined distance x3 to complete the preparation for the start of the back side recording. I do.

  Next, a case of thick recording paper (recording medium) having relatively high rigidity will be described. FIG. 19 is a schematic cross-sectional side view showing the registration operation at the front end of the back surface when thick recording paper is used. FIG. 19A shows a state in the middle of step S13 similarly to FIG. 18A, and FIG. 19B shows a state when step S13 ends. Next, in step S20, the LF motor 26 is rotated in the reverse direction while the paper passing guide 70 is in the lowered position, and the distance from the leading end of the back surface of the recording paper 4 at the position stopped in step S13 to the nip of the paper feed roller 21 is determined. The recording paper 4 is conveyed by a distance x4 slightly longer than the recording paper 4. As a result, similarly to the case of thin recording paper, the leading end of the back surface of the recording paper 4 reaches the nip portion of the paper feed roller 21 which is rotating in the reverse direction, and a loop is formed by the further pressing of the paper. Then, the leading end of the back surface of the recording paper 4 becomes parallel to the paper feed roller 21, and 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 turned in the forward direction, the front end of the back surface of the recording paper 4 is nipped by the nip portion, and is conveyed by a predetermined distance x3 to prepare for the start of back surface recording. In step S19 or step S21, the LF motor 26, which has been rotating in the reverse direction, changes its rotational direction to forward rotation. At this time, the double-sided pendulum arm 117 swings in the direction of arrow a in FIG. Then, the engagement between the two-sided planetary gear B119 and the reverse delay gear A121 is released. When the LF motor 26 rotates in the reverse direction, the reversing delay gear A121 and the reversing delay gear B122 were engaged with each other by the projection, but at the same time, the reversing delay gear spring 124, which is a torsion coil spring interposed between the two. Although it is in a compressed state, the reversal delay gear A121 is in a free state, and the reversal delay gear spring 124 expands. Therefore, the reversal delay gear A121 is reversed by approximately one rotation and returns to the initial state.

  Next, in step S22, the lift mechanism is set to the first position, and preparation for starting backside recording is completed. Here, the reason why the sheet passing guide 70 is at the lowered position during the registration operation when a thick recording sheet is used will be described. As in the case of the thin recording paper, when the loop is generated as shown in FIG. 18C, the rigidity of the recording paper is so high that the recording paper 4 is pinched before reaching the nip portion. It is transported along the holder 23. As a result, even if the recording sheet is further conveyed after reaching the nip portion and attempts to generate a loop, the loop generation space is already exhausted, and the loop is not generated. For this reason, registration may not be properly performed in some cases.

  If a loop is not generated, the recording paper sandwiched between the two-sided roller A108 and the paper feed roller 21 cannot be slackened (loose). This is because, when a mechanism such as the double-sided pendulum arm 117 is used for the double-sided rollers drive mechanism as in the present embodiment, during the period from the reverse rotation of the LF motor 26 in step S20 to the normal rotation of the LF motor 26 in step S21. In this case, the time required for the double-sided pendulum arm 117 to swing is required, during which time the double-sided roller A108 and the double-sided roller B109 stop.

  Since the paper feed roller 21 is directly connected to the LF motor 26, there is no stop period, and contradiction occurs in the paper transport speed. If there is a slack in the recording paper, the inconsistency in the paper transport speed can be absorbed by removing the slack during step S21, but if there is no slack, the inconsistency in the paper transport speed cannot be absorbed. Then, the paper feed roller 21 forcibly tries to convey the recording paper, but since the rear of the recording paper 4 is sandwiched by the double-sided roller A108, there may be a case where the paper is not actually conveyed. As a result, the conveyance amount of the front end of the back surface of the recording paper 4 may be deviated, and the upper end margin of the back surface may be shorter than expected. In order to solve the above situation, by setting the paper passing guide 70 at the lowered position, a gap in the height direction with the pinch roller holder 23 is sufficiently secured, and a loop generating space is secured. As a result, even when a thick recording paper having relatively high rigidity is used, a good registration operation can be performed.

  Next, in step S23, recording on the back surface of the recording paper 4 is performed. At this time, the rear end of the rear surface of most of the recording paper 4 is still nipped by the double-sided roller A108. If the rotation of the double-sided roller A108 is stopped as it is, a load for pulling the recording paper backward is generated, which may deteriorate the paper conveyance accuracy, which is not preferable. Therefore, the drive of the double-sided roller A108 is configured to continue while at least the rear end portion of the rear surface of the recording paper 4 is sandwiched by the double-sided roller A108. The state of the double-sided roller drive mechanism at this time is as shown in FIG.

  FIG. 16D is a schematic side cross-sectional view showing the operation state of the rollers driving mechanism of the automatic duplex unit 2 while the LF motor 26 is rotating in the forward direction after the reversing operation of the recording paper. is there. That is, when the LF motor 26 starts rotating in the forward direction from the state shown in FIG. 16C, the double-sided pendulum arm 117 swings in the direction of arrow a in FIG. At this time, the stop arm 127 swings in the direction of arrow h in FIG. 15, and even if the double-sided pendulum arm 117 swings in the direction of arrow a in FIG. , The double-sided planetary gear A118 engages with the double-sided roller idler gear 124, and the driving force is transmitted.

  Thereafter, when the LF motor 26 continues to rotate in the forward direction, the follower pin 127a is guided by the spiral groove gear 120 and moves toward the inner circumference, and the stop arm 127 swings in the direction of arrow g in FIG. During the swinging, the stop arm 127 abuts on the double-sided pendulum arm spring 132 and deforms the double-sided pendulum arm spring 132. Due to the reaction force due to the deformation of the double-sided pendulum arm spring 132, a force for swinging the double-sided pendulum arm 117 in the direction of arrow b in FIG. In some cases, the engagement between the gear tooth surfaces is stronger, so that the engagement between the double-sided planetary gear A118 and the double-sided roller idler gear 124 does not come off, and the driving is continued. FIG. 16D shows this state.

  As described above, even when the intermittent drive with rotation and stop is performed, the engagement between the double-sided planetary gear A118 and the double-sided roller idler gear 124 is not lost because the tooth surfaces of the gears overlap. Further, when the recording operation on the back surface of the recording paper 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 the maximum displaced state. However, the double-sided pendulum arm spring 132 is moved so that the force at which the gear tooth surfaces mesh with each other is larger than the force for swinging the double-sided pendulum arm 117. Since the load is set, the engagement between the gears does not come off as long as the LF motor 26 continues to rotate in the forward direction. When the recording operation on the back surface of the recording paper 4 is completed, the process proceeds to step S24.

  Next, in step S24, a paper discharge operation for discharging the recording paper 4 onto a paper discharge tray (not shown) is performed. The paper discharge operation is performed by transporting the recording paper 4 to the outside of the recording unit main body 1 by the second paper discharge roller 31 by continuing the forward rotation of the LF motor 26. Next, in step S25, a check is made of the absolute position of the front end of the back surface. This is because the follower pin 127a may not reach the innermost circumference of the spiral groove gear 120 when a short recording sheet is used. In this case as well, the LF motor 26 is rotated by a predetermined length so that the follower pin 127a always reaches the innermost circumference of the spiral groove gear 120 when the back surface recording operation of the recording paper 4 is completed. .

  Next, in step S26, the double-sided rollers drive mechanism is initialized. As described above, since the force charged by the double-sided pendulum arm spring 132 is held by the engagement between the double-sided planetary gear A118 and the double-sided roller idler gear 124, it is only necessary to rotate the LF motor 26 by a small amount in the reverse direction. The agreement is broken. That is, when the LF motor 26 is rotated in the reverse direction, the double-sided pendulum arm 117 attempts to swing in the direction of the arrow b in FIG. 15, so that the double-sided planetary gear A118 and the double-sided roller idler gear 124 are disengaged and charged. The double-sided pendulum arm spring 132 swings in the direction of arrow b in FIG. The state of the double-sided rollers drive mechanism at this time is the state shown in FIG.

  In this state, since the posture of the double-sided pendulum arm spring 132 has returned to its original state, when the LF motor 26 rotates in the forward direction from here, the double-sided pendulum arm 117 attempts to swing in the direction of arrow a in FIG. However, since the follower pin 127a is located near 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 double-sided planetary gear A118 cannot engage with the double-sided roller idler gear 124. Further, even if 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 double-sided roller A108 and the double-sided roller B109 are not driven. As described above, since the reversal delay gear A121 has been initialized in step S19 or step S21, all initialization of the double-sided roller driving mechanism ends in step S26. Thus, the automatic double-sided recording operation is completed. When performing the automatic double-sided recording operation continuously, the same sequence may be repeated.

  In this embodiment, the elastic contact between the double-sided pendulum arm 117 and the stop arm 127 is realized by the operation of the double-sided pendulum arm spring 132, but the gist of the present invention is not limited to this. , Can be configured as follows. FIG. 17 is a schematic side sectional view showing the operation state of the rollers driving mechanism of the automatic duplex unit 2 as in FIG. The double-sided pendulum arm 117 shown in FIG. 17 has an arm with low elasticity, and the arm and the stop arm 127 can be in contact with each other. Hereinafter, the operation of the configuration according to the other embodiment will be briefly described.

  The operations from FIG. 17 (a) to FIG. 17 (c) are the same as the operations from FIG. 16 (a) to FIG. 16 (c), and a description thereof will be omitted. FIG. 17D shows a state in which 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 of the double-sided pendulum arm 117. Since the arm of the double-sided pendulum arm 117 does not have much elasticity, when pressed by the stop arm 127, a force acts to rotate the double-sided pendulum arm 117 in the direction of arrow b in FIG. The force acts in a direction to release the engagement between the double-sided planetary gear A 118 and the double-sided roller idler gear 124.

  The force for disengaging the engagement balances with the pressure acting between the tooth surfaces of the double-sided planetary gear A118 and the double-sided roller idler gear 124 and the elasticity and sliding force of the gear tooth surface. The force to release the engagement increases, overcoming the force between the tooth surfaces, and forcibly cancels the engagement between the double-sided planetary gear A 118 and the double-sided roller idler gear 124. Simultaneously, the rotation of the double-sided roller A108 and the double-sided roller B109 is stopped. FIG. 17E shows this state. The rotation of the roller is stopped at an appropriate time after the rear end of the back surface of the recording paper 4 has passed the double-sided roller A108 in step S23.

  After disengagement of the gear, even if the LF motor 26 rotates in the forward direction, the stop arm 127 prevents the double-sided pendulum arm 117 from swinging in the direction of arrow a in FIG. Until the motor 26 rotates in the reverse direction, the automatic duplex unit 2 is not driven. Further, similarly to the first embodiment, since the reversal delay gear A121 is also made in step S19 or step S21, the initialization of the roller driving mechanism of the automatic duplex unit 2 has been completed at this time. Thus, the load for rotating the two-sided roller A108 and the two-sided roller B109 during the recording operation on the back surface can be eliminated, and the rotational load of the LF motor 26 can be reduced. The above is another embodiment of the roller driving mechanism of the automatic duplex unit 2.

  Note that the gist of the present invention is not limited to this, and it is also possible to perform control in which the position of the lift mechanism is changed. That is, in the above description, the paper passing guide 70 is in the up state in the normal standby state, but it can be set in the down state. Specifically, the normal lift mechanism is set to the third position, and control for moving the lift mechanism from the third position to the first position before step S1 is added. 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, since the pinch roller 22 is in the released state in the standby state, it is suitable for feeding thick paper or the like from the discharge roller side. The above is the description of the automatic double-sided recording operation along the flowchart showing the operation sequence.

  In the embodiments described above, embodiments of the present invention as listed below are described. Embodiment 1: a paper feed roller pair including a paper feed roller and a pinch roller pressed against the paper feed roller, at least one pair of paper discharge rollers disposed downstream of the paper feed roller pair in the transport direction, and In a double-sided recording apparatus provided with a paper transport mechanism having a paper discharge roller pair consisting of a rotating body pressed against a paper discharge roller, the trailing end of the recording medium separates from the paper feed roller pair during the first-side recording. It is possible to convey the recording medium to the position, and then, after separating the paper feed roller and the pinch roller and conveying the recording medium in the opposite direction to the first surface recording by the paper discharge roller pair, A two-sided recording apparatus, wherein the recording medium is conveyed to a sheet reversing unit by pressing the paper feed roller and the pinch roller again and continuing the conveyance in the reverse direction.

  According to the configuration of the first embodiment, since recording can be performed while transporting the recording medium once from the paper feed roller until the recording medium comes off, recording without margins can be performed over the entire range of the recording medium. Since the paper is conveyed in the opposite direction with a gap formed between the paper feed roller and the paper feed roller, the recording medium can be reliably held again by the paper feed roller and the pinch roller. A double-sided recording apparatus capable of reliably preventing a jam or the like is provided.

  Embodiment 2: The gap between the paper feed roller and the pinch roller when the two are separated from each other is set to be larger than the deformation amount of the recording medium after recording the first surface of the recording medium. A two-sided recording apparatus according to aspect 1. According to the configuration of the second embodiment, the recording medium can be more easily conveyed to the gap between the paper feed roller and the pinch roller. As a result, it is possible to reliably carry out the pinching and to reliably prevent paper jams and paper jams.

  Embodiment 3: The double-sided recording apparatus according to Embodiment 1 or 2, wherein the conveyance of the recording medium is started in a reverse direction after a lapse of a predetermined time from the end of recording on the first surface of the recording medium. According to the configuration of the third embodiment, further, by sufficiently drying the recording ink on the first surface, it is possible to obtain an effect that ink stains on the paper feed roller or the pinch roller or stains on the recording paper itself can be eliminated. Can be

  Embodiment 4: The paper feed roller and the pinch roller are separated at a first predetermined time after the end of recording on the first surface of the recording medium, and the rear end of the first surface is extended beyond the nip portion of the paper feed roller. The sheet is conveyed in the reverse direction, whereupon the conveyance of the recording medium is stopped for a second predetermined time, and then the paper feed roller and the pinch roller are pressed again and the conveyance in the reverse direction is continued, so that the sheet is covered by the sheet reversing section. The double-sided recording apparatus according to any one of embodiments 1 to 3, wherein the second predetermined time is longer than the first predetermined time when conveying the recording medium. According to the configuration of the fourth embodiment, the rear end of the first surface is conveyed in the reverse direction after the small first predetermined time beyond the nip portion of the paper feed roller, so that the recording medium absorbs ink and the like. A double-sided recording apparatus is provided in which a recording medium can be transported to a gap between a paper feed roller and a pinch roller before the recording medium is deformed, and paper jams and paper jams can be reliably prevented.

  Embodiment 5: The paper feed roller and the pinch roller are separated at a third predetermined time after the end of recording on the first surface of the recording medium, and the rear end of the first surface is extended beyond the nip portion of the paper feed roller. By conveying the recording medium in the reverse direction and then pressing the paper feed roller and the pinch roller again, the conveyance of the recording medium is stopped for a fourth predetermined time, and then the reverse conveyance of the recording medium is restarted. The double-sided recording apparatus according to any one of embodiments 1 to 3, wherein the fourth predetermined time is longer than the third predetermined time when the recording medium is transported to the sheet reversing unit. According to the configuration of the fifth embodiment, when there is a margin at the rear end of the first surface, the pinch roller is pressed against the margin, and after that, the recording paper waits for the fourth predetermined time, so that the recording paper A double-sided recording apparatus is provided which can reduce the amount of deformation due to absorption of paper and the like and reliably prevent paper jams and paper jams. Embodiment 6: The double-sided recording apparatus according to any one of Embodiments 1 to 5, wherein recording is performed on a recording medium by an inkjet recording unit that discharges ink from a discharge port.

  Embodiment 7: The total time from the end of recording on the first surface to the end of the second predetermined time or the fourth predetermined time is made variable by the density per unit area of data recorded on the first surface. The double-sided recording apparatus according to any one of embodiments 1 to 6, wherein Embodiment 8: The total time from the end of printing on the first surface to the end of the second predetermined time or the fourth predetermined time is made variable depending on the type of ink used for printing. A two-sided recording apparatus according to any one of aspects 1 to 6. Embodiment 9: The total time from the end of recording on the first surface to the end of the second predetermined time or the end of the fourth predetermined time is made variable according to atmospheric conditions such as environmental temperature and environmental humidity. The double-sided recording apparatus according to any one of the first to sixth embodiments.

  Embodiment 10: The total time from the end of recording on the first surface to the end of the second predetermined time or the fourth predetermined time is made variable depending on the type of recording medium. 7. The double-sided recording apparatus according to any one of claims 6 to 6. According to the configurations of Embodiments 6 to 10, the drying standby time is variable depending on the amount of ink to be ejected per unit area, the type of ink, the atmosphere of the recording apparatus such as environmental temperature and environmental humidity, or the type of recording medium. As a result, the recording medium on which the first surface has been recorded can be efficiently dried, and unnecessary drying processing can be omitted, thereby shortening the drying standby time and shortening the recording operation time. Can be

  In the above embodiment, the serial recording apparatus that performs recording while moving the recording head as a recording unit in the main scanning direction has been described as an example. The present invention can be similarly applied to a line-type recording apparatus that performs recording only by sub-scanning (paper feed) using a line-type recording unit having a length covering the same, and can achieve the same effect. It is. Further, the present invention can be freely carried out regardless of the number of recording means, and can be used for color recording using a plurality of recording means using inks of different colors 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 using inks of the same color and different densities, and a recording apparatus combining these. The same effect can be achieved.

  Furthermore, when the recording apparatus is an ink jet recording apparatus, the present invention uses a replaceable head cartridge in which the recording head and the ink tank are integrated, separates the recording head from the ink tank, and supplies ink between the recording head and the ink tank. The same configuration can be applied to any arrangement of the recording head and the ink tank, such as a configuration in which the recording head and the ink tank are connected with each other, and the same effect can be obtained. Incidentally, the present invention, when the recording apparatus is an inkjet recording apparatus, in addition to a recording apparatus using an inkjet recording head of a method of discharging ink using thermal energy, for example, an electromechanical transducer such as a piezo element It can be similarly provided to an ink jet recording apparatus using another ink discharging method, such as a recording apparatus using an ink jet recording head of a method of discharging ink, and can achieve the same operation and effect. is there.

  According to the double-sided recording apparatus according to the embodiment of the present invention described above, since recording can be performed while transporting the recording medium once from the paper feed roller until the recording medium comes off, it is possible to perform recording without margins over the entire range of the recording medium. In addition, since the sheet is conveyed in the opposite direction with a gap formed between the pinch roller and the paper feed roller by separating the pinch roller, the recording medium is absorbed before the recording medium is absorbed and deformed. To the gap between the paper feed roller and the pinch roller, the paper feed roller and the pinch roller can reliably pinch the recording medium again, and reliably prevent paper jams and paper jams. be able to.

FIG. 1 is a schematic perspective view illustrating an entire configuration of a double-sided recording apparatus according to an embodiment of the present invention. FIG. 1 is a schematic side sectional view illustrating an entire configuration of a double-sided recording apparatus according to an embodiment of the present invention. FIG. 2 is a schematic perspective view illustrating a pinch roller pressure contact / separation mechanism of the duplex recording apparatus according to the embodiment of the present invention. FIG. 2 is a schematic side cross-sectional view illustrating a pinch roller pressure contact / separation mechanism of the duplex recording apparatus according to the embodiment of the present invention. FIG. 2 is a schematic side sectional view showing a PE sensor vertical mechanism of the double-sided recording apparatus according to one embodiment of the present invention. FIG. 2 is a schematic side cross-sectional view illustrating a paper passing guide up-and-down mechanism of the duplex recording apparatus according to the embodiment of the present invention. FIG. 2 is a schematic perspective view showing a guide shaft up-and-down mechanism of the duplex recording apparatus according to one embodiment of the present invention. FIG. 2 is a schematic side sectional view showing a guide shaft up-and-down mechanism of the duplex recording apparatus according to the embodiment of the present invention. FIG. 2 is a schematic perspective view showing a drive mechanism of a lift cam shaft of the double-sided recording apparatus according to one embodiment of the present invention. FIG. 3 is a schematic side cross-sectional view showing a state at each position of a lift mechanism of the duplex recording apparatus according to the embodiment of the present invention. 6 is a timing chart showing an operation state of a lift mechanism of the double-sided recording apparatus according to one embodiment of the present invention. FIG. 2 is a schematic side cross-sectional view showing a state (back-conveying state) of the recording medium at the start of the backfeed of the recording medium according to the embodiment of the present invention. FIG. 2 is a schematic side sectional view illustrating a configuration of an automatic duplex unit (automatic reversing unit, sheet reversing unit) of the duplex recording apparatus according to the embodiment of the present invention. FIG. 4 is a schematic side sectional view illustrating an operation of a flap in an automatic duplex unit of the duplex recording apparatus according to the embodiment of the present invention. FIG. 2 is a schematic side sectional view showing an automatic duplex unit driving mechanism of the duplex recording apparatus according to the embodiment of the present invention. FIG. 5 is a schematic side sectional view sequentially showing the operation state of the automatic duplex unit driving mechanism of the duplex recording apparatus according to the embodiment of the present invention. FIG. 7 is a schematic side sectional view sequentially showing another operation state of the automatic duplex unit driving mechanism of the duplex recording apparatus according to the embodiment of the present invention. FIG. 4 is a schematic side cross-sectional view showing a registration operation at the front end of the back surface when a thin recording sheet is used in the double-sided recording apparatus according to the embodiment of the present invention. FIG. 4 is a schematic side cross-sectional view showing a registration operation at the front end of the back surface when a thick recording sheet is used in the double-sided recording apparatus according to the embodiment of the present invention. 6 is a flowchart illustrating a sequence of an automatic double-sided printing operation of the double-sided printing apparatus according to an embodiment of the present invention. FIG. 1 is a schematic block diagram illustrating a control circuit configuration of a double-sided recording apparatus according to an embodiment of the present invention. FIG. 7 is a schematic side sectional view showing another configuration example of the automatic duplex unit of the duplex recording apparatus according to an embodiment of the present invention.

Explanation of reference numerals

1 Recording unit body (device body)
2 Automatic duplex unit (automatic reversing unit, paper reversing unit)
4 Recording medium (recording paper)
10 Chassis 11 Recording means (recording head)
12 Ink tank 13 Carriage 14 Guide shaft 14a Right guide shaft cam 14b Left guide shaft cam 14c Right guide shaft cam gear 15 Guide rail 16 Carriage belt 17 Carriage motor 20 Idler pulley 21 Paper feed roller 22 Pinch roller 23 Pinch roller holder 24 Pinch roller spring 26 LF motor 29 Platen 30 First discharge roller 31 Second discharge roller 32 First spur train (rotating body)
33 2nd spur train (rotating body)
34 Spur base 36 Maintenance unit (discharge recovery device)
37 Main ASF (Automatic paper feeder)
38 ASF base 39 Paper feed roller 40 Separation 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 pressing cam 60 Pinch roller spring pressing cam 61 PE sensor lever pressing cam 65 Paper passing guide pressing cam 66 PE sensor lever (paper detection lever)
67 PE sensor 68 PE sensor lever spring 70 Paper passing 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 Double-sided roller A
109 Double-sided roller B
112 Double-sided pinch roller A
113 Double-sided Pinch Roller B
116 Double-sided sun gear 117 Double-sided pendulum arm 118 Double-sided planetary gear A
119 Double Sided Planetary Gear B
120 Spiral groove gear 127 Stopper arm 128 Stopper arm spring 131 Evacuation path 301 Control board 305 ASF sensor 307 Head driver 308 Host device 310 CPU
311 ROM
312 RAM

Claims (14)

A paper feed roller pair including a paper feed roller and a pinch roller pressed against the paper feed roller; and at least one pair of paper discharge rollers and the paper discharge roller disposed downstream of the paper feed roller pair in the transport direction. In a double-sided recording apparatus having a paper transport mechanism having a discharge roller pair formed of a rotating body pressed against,
During the first-side recording, the recording medium can be transported to a position where the trailing end of the recording medium separates from the paper feed roller pair. Then, the paper feed roller and the pinch roller are separated from each other to discharge the paper. After the recording medium is conveyed by the pair of paper rollers in the direction opposite to that of the first side recording, the paper feed roller and the pinch roller are pressed again to continue the conveyance in the reverse direction, so that the recording is performed on the sheet reversing unit. A double-sided recording device for transporting a medium.   2. The gap between the paper feed roller and the pinch roller when the pinch roller is separated is set to be larger than the deformation amount of the recording medium after recording on the first surface of the recording medium. Double-sided recording device.   2. The double-sided recording apparatus according to claim 1, wherein the conveyance of the recording medium is started in a reverse direction after a lapse of a predetermined time from the end of recording on the first surface of the recording medium.   After a first predetermined time from the end of recording on the first surface of the recording medium, the paper feed roller and the pinch roller are separated, and the rear end of the first surface is conveyed in a reverse direction beyond the nip portion of the paper feed roller. Then, the conveyance of the recording medium is stopped for the second predetermined time, and then the paper feed roller and the pinch roller are pressed again to continue the conveyance in the reverse direction to convey the recording medium to the sheet reversing unit. 2. The double-sided recording apparatus according to claim 1, wherein the second predetermined time is longer than the first predetermined time.   After a third predetermined time from the end of recording on the first surface of the recording medium, the paper feed roller and the pinch roller are separated, and the rear end of the first surface is conveyed in a reverse direction beyond the nip portion of the paper feed roller. Then, after pressing the paper feed roller and the pinch roller again, the conveyance of the recording medium is stopped for a fourth predetermined time, and then the conveyance of the recording medium in the reverse direction is restarted, so that 2. The double-sided recording apparatus according to claim 1, wherein the fourth predetermined time is longer than the third predetermined time when the recording medium is transported.   The double-sided recording apparatus according to claim 1, wherein recording is performed on a recording medium by an inkjet recording unit that discharges ink from a discharge port.   The total time from the end of recording on the first surface to the end of the second predetermined time or the end of the fourth predetermined time is made variable by the density per unit area of data recorded on the first surface. The double-sided recording apparatus according to claim 1.   6. The printing apparatus according to claim 1, wherein a total time from the end of printing on the first surface to the end of the second predetermined time or the fourth predetermined time is made variable depending on the type of ink used for printing. The double-sided recording device according to any one of the above.   The total time from the end of recording on the first surface to the end of the second predetermined time or the end of the fourth predetermined time is made variable depending on atmospheric conditions such as environmental temperature and environmental humidity. 6. The double-sided recording device according to any one of 1 to 5.   6. The recording medium according to claim 1, wherein a total time from the end of recording on the first surface to the end of the second predetermined time or the end of the fourth predetermined time is variable depending on the type of the recording medium. A double-sided recording apparatus according to any one of the above. A first transport roller that transports a recording medium in a predetermined transport direction, a pinch roller that pinches a sheet in cooperation with the transport roller, and a print head that ejects ink downstream of the transport roller in the transport direction A recording unit that performs recording on a sheet conveyed by the conveyance roller by using a second conveyance roller that conveys a sheet on the downstream side in the conveyance direction of the recording unit, and in cooperation with the second conveyance roller. In a double-sided recording apparatus having a rotating body for nipping a sheet and a reversing unit for reversing the front and back of a sheet conveyed by the conveyance roller in a direction opposite to the conveyance direction and conveying the sheet to the first conveyance roller,
The recording is performed by the recording unit in a state where the trailing edge of the sheet is located downstream of the nip between the first conveying roller and the pinch roller, and then the sheet is separated in a state where the first conveying roller and the pinch roller are separated from each other. The sheet is conveyed in a direction opposite to the conveyance direction by the second conveyance unit until a rear end passes between the first conveyance roller and the pinch roller, and thereafter, the sheet is conveyed by the first conveyance roller and the pinch roller. A double-sided recording apparatus, wherein a sheet is nipped and conveyed to the reversing means.   Recording is performed by the recording unit in a state where the trailing edge of the sheet is located downstream of the nip between the first transport roller and the pinch roller, and then the trailing edge of the sheet is transported by the second transport unit to the first transport position. Transporting the sheet until it passes between a roller and the pinch roller, temporarily stopping the sheet, and thereafter nipping the sheet by the first transport roller and the pinch roller and transporting the sheet to the reversing means. The double-sided recording apparatus according to claim 11, wherein:   Recording is performed by the recording unit in a state where the trailing edge of the sheet is located downstream of the nip between the first transport roller and the pinch roller, and then the trailing edge of the sheet is transported by the second transport unit to the first transport position. Transporting the sheet until it passes between a roller and the pinch roller, stopping the sheet for a predetermined time, and thereafter nipping the sheet by the first transport roller and the pinch roller and transporting the sheet to the reversing means. The double-sided recording apparatus according to claim 11.   In the state where the trailing edge of the sheet is located downstream of the nip between the first transport roller and the pinch roller, recording is performed by the recording means so that a margin remains at the trailing edge of the sheet, and then the second transport means Conveys the sheet until the trailing edge of the sheet passes between the first conveyance roller and the pinch roller, clamps a margin of the sheet by the first conveyance roller and the pinch roller, and stops the sheet for a predetermined time. 12. The double-sided recording apparatus according to claim 11, wherein the sheet is conveyed to the reversing means after that.

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