JP2009029144A - Recording device and recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to detect edge parts of a medium without causing paper clogging when the medium is reversely carried. <P>SOLUTION: This recording device comprises: (A) a carrying mechanism carrying a medium to a progressive direction and an opposite direction; (B) a head recording a dot in the medium; (C) a sensor detecting the presence/non-presence of the medium in a non-contacted state; (D) a reversal mechanism reversing the medium; and (D) a controller, when the carrying mechanism is allowed to carry the medium in the progressive direction for recording the right side of the medium in the head, detecting the edge parts of the medium by the sensor. After the recording of the right side, when the carrying mechanism is allowed to carry the medium in a reverse direction for reversing the medium, the controller detects the edge parts of the medium by the sensor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a recording apparatus and a recording method.

  Here, the recording apparatus is not limited to a printer, a copier, a facsimile, or the like that performs recording by an ink jet method, but widely includes apparatuses used for manufacturing a color filter of a liquid crystal display, an organic EL display, a biochip, and the like.

  As an example of a recording apparatus, an ink jet printer is known. In a general ink jet printer, a dot forming operation for forming dots by ejecting ink from a moving head and a transport operation for transporting a medium (paper, cloth, OHP paper, etc.) are alternately repeated to generate an image. Print.

Such a printer may be provided with a sensor for detecting the edge of the medium. As such a sensor, there is a sensor having a lever arranged rotatably in the middle of a medium transport path and a photo interrupter that changes a signal level of a detection signal by the lever (for example, Patent Document 1). See).
JP-A-8-259037

A sensor using such a lever may cause a paper jam when the paper is conveyed in the reverse direction.
An object of the present invention is to detect an end portion of a medium during reverse conveyance while avoiding a medium jam.

  The main invention for achieving the above object is as follows: (A) a transport mechanism for transporting the medium in the forward and reverse directions; (B) a head for recording dots on the medium; and (C) whether or not the medium is present. A sensor that detects by contact; (D) a reversing mechanism that reverses the medium; and (D) when the medium is transported in the forward direction by the transport mechanism to cause the head to record the front surface of the medium. And a controller for detecting the edge of the medium by the sensor when the medium is conveyed in the reverse direction by the conveying mechanism to cause the reversing mechanism to invert the medium after recording the front surface. And a controller for detecting an end of the medium by the sensor.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  At least the following matters will become clear from the description of the present specification and the accompanying drawings.

(A) a transport mechanism for transporting the medium in the forward direction and the reverse direction;
(B) a head for recording dots on the medium;
(C) a sensor for detecting the presence or absence of the medium in a non-contact manner;
(D) a reversing mechanism for reversing the medium;
(D) a controller that detects the edge of the medium by the sensor when the transport mechanism transports the medium in the forward direction in order to cause the head to record the front surface of the medium;
A controller that detects the edge of the medium by the sensor when the medium is conveyed in the reverse direction by the conveying mechanism to cause the reversing mechanism to invert the medium after recording the front surface;
A recording apparatus comprising:
According to such a recording apparatus, it is possible to detect the end of the medium without clogging the medium during reverse conveyance.

  Preferably, the sensor includes a light emitting unit and a light receiving unit, and the recording apparatus further includes a lower guide and an upper guide for guiding the medium between the light emitting unit and the light receiving unit. Thereby, both shortening the distance between the light emitting unit and the light receiving unit and allowing the medium to pass between the light emitting unit and the light receiving unit can be achieved.

  The sensor includes an upper protrusion and a lower protrusion, the upper protrusion includes one of the light emitting part and the light receiving part, the lower protrusion includes the other, and the lower guide includes A base surface, a rib formed so as to rise from the base surface and contacting the medium, and an insertion portion for inserting the lower protrusion, and an opening at the position of the optical axis of the sensor in the lower guide It is desirable that the opening is provided on the base surface between the ribs. Thereby, a medium clogging can be prevented.

  In addition, it is preferable that the upper surface of the lower protrusion is positioned above the base surface of the lower guide. Thereby, the detection accuracy of a sensor can be raised.

  The lower guide further includes a raised portion for covering the lower protruding portion, and an inclined surface is formed between the raised portion and the base surface at the forward upstream side and the forward downstream side of the raised portion. It is desirable. Thereby, a medium clogging can be prevented.

  The recording apparatus further includes a flexible seal member, the sensor is fixed to the lower guide, and the upper guide is provided to be swingable with respect to the lower guide, It is preferable that the seal member seals a boundary between the sensor and the upper guide. Thereby, it is possible to prevent the medium from entering the boundary between the upper guide and the sensor whose posture changes relatively.

  In addition, a first convex portion that supports the medium, a second convex portion that supports the medium and is provided on the downstream side in the forward direction from the first convex portion, the first convex portion, and the second convex portion. And a groove provided between the controller and the controller while causing the transport mechanism to transport the medium so that the rear end of the medium does not become downstream in the forward direction from the first convex portion. When recording the front surface of the medium on the head and recording the back surface of the medium, the head is transported to the transport mechanism so that the rear end of the medium is positioned on the groove. It is desirable that the rear end of the medium is recorded. This makes it difficult for the rear end of the medium to be caught by the first convex portion during reverse conveyance after recording on the front surface, thereby preventing clogging of the medium.

Feed the media to the transport mechanism,
Detecting the end of the medium by a non-contact sensor before feeding the medium to the transport mechanism;
Recording the front surface of the medium while transporting the medium in the forward direction by the transport mechanism;
After recording the front surface, the medium is conveyed in a reverse direction opposite to the forward direction in order to reverse the medium by a reversing mechanism;
A recording method, wherein an edge of the medium is detected by the non-contact sensor when the medium is conveyed in a reverse direction.
According to such a recording method, it is possible to detect the edge of the medium without clogging the medium during reverse conveyance.

=== Outline of the printer ===
FIG. 1 is a schematic side sectional view of a printer. FIG. 2 is a block diagram of the overall configuration of the printer.

  The printer 1 includes a rear paper feed unit 2, a front paper feed unit 3, a carriage unit 4, a transport unit 5, a paper discharge unit 6, and a controller 10.

  The rear paper feed unit 2 is a mechanism that feeds the paper P stocked on the back of the printer 1 to the transport unit 5. The front paper feed unit 3 is a mechanism that feeds the paper P on the tray 25 that can be set from the front of the printer 1 to the transport unit 5. The carriage unit 4 is a mechanism that forms an image on the paper P by ejecting ink from the head 48 while the carriage 46 is moving. The carriage 46 is guided by a shaft 47 and moves in the direction perpendicular to the paper surface of FIG. The transport unit 5 is a mechanism that transports the fed paper P and controls the position of the paper P relative to the head 48. The paper discharge unit 6 is a mechanism for discharging the paper P on which an image is formed to the outside of the printer 1. The controller 10 controls the entire printer 1 and controls each unit based on print data received from an external device.

  Further, the reversing unit 100 can be attached to the printer 1 as an option. The reversing unit 100 is a mechanism for reversing the paper P during double-sided printing for printing both sides of the paper P. Various sensors (sensor groups) are provided inside the printer 1. An optical sensor 37 to be described later is included in this sensor group. The controller 10 controls each unit based on the detection result of the sensor group.

  Inside the printer 1, a guide roller 40, an upper guide 43, a lower guide 44, and a platen 45 are provided as guide members for guiding the paper P being fed or transported.

=== Path of Paper P ===
<Rear feeding>
With reference to FIG. 1, the path of the paper P during rear paper feeding will be described. The operation / drive timing of each member is controlled by the controller 10.
When feeding is started, the hopper 12 is lifted around the fulcrum 12 a, and the uppermost sheet of the sheets P stacked on the hopper 12 comes into contact with the sheet feeding roller 11. When the rear paper feed roller 11 rotates, the paper P is fed downstream. The paper P to be fed is sandwiched between the rear paper feed roller 11 and the retard roller 13. The retard roller 13 is given a predetermined rotational resistance by a torque limiter mechanism, and the paper P is prevented from being double fed. The paper retained by the retard roller 13 is returned onto the hopper 12 by the return lever 14.

  FIG. 3 is an explanatory diagram of the rear paper feed path. As the rear paper feed roller 11 continues to rotate, the paper P is fed from the hopper 12 into the printer 1. Normally, the leading edge of the fed paper P is guided to the lower right side in the figure by the rear paper feed guide 15. When the rear paper feed roller 11 continues to rotate, the leading edge of the paper P comes into contact with the lower guide 44 and is guided to the right side in the drawing by the lower guide 44. If the paper P is warped upward, the leading edge of the paper P contacts the upper guide 43 or the guide roller 40 and is guided to the right side in the drawing by the upper guide 43. The leading edge of the paper P guided by the upper guide 43 or the lower guide 44 passes through an optical sensor 37 described later and reaches the transport unit 5.

<Front feeding>
FIG. 4 is an explanatory diagram of the front paper feed path. Hereinafter, the path of the paper P during front paper feeding will be described with reference to FIG.
In the tray 25, the pickup roller 26 is in contact with the uppermost paper P. When the pickup roller 26 rotates in this state, the paper P is fed out to the front paper feed roller 28. The paper P fed out from the tray 25 is sandwiched between the front paper feed roller 28 and the separation roller 29, and is fed to the assist roller 30 by the rotation of the front paper feed roller 28 while being prevented from being double fed by the separation roller 29. It is. The paper P sandwiched between the front paper feed roller 28 and the assist roller 30 is fed as the front paper feed roller 28 continues to rotate. At this time, the leading edge of the paper P pushes up the hopper 49, and the paper P is guided to the right side in the drawing by the lower surface of the hopper 49. The leading edge of the paper P guided by the hopper 49 passes through an optical sensor 37 (described later) while reaching the transport unit 5 while being guided by the upper guide 43 or the lower guide 44.

<Convey / Discharge>
5A to 5C are explanatory diagrams of conveyance and paper discharge. Hereinafter, the state of the paper P during conveyance by the conveyance unit 5 will be described with reference to FIG.

  The paper P fed from the rear paper feed unit 2 or the front paper feed unit 3 is sandwiched between the transport roller 41 and the transport-side driven roller 42 of the transport unit 5. The rotation amount of the transport roller 41 is controlled by the controller 10, and the paper P is transported while the position of the paper P with respect to the head 48 is controlled. That is, the paper P is transported by the transport roller 41. At this time, the paper P is supported from below by the platen 45. As will be described later, the platen 45 is provided with a groove for borderless printing.

  When the paper P is transported to a position facing the head 48, a dot forming operation for ejecting ink from the head 48 to form dots on the paper P while the carriage 46 is moving, and transporting the paper P by a predetermined transport amount. The conveyance operation is alternately repeated, and an image composed of innumerable dots is formed on the paper P. If the transport operation is continued several times, the leading edge of the paper P passes through the auxiliary roller 57, and if the transport operation is continued several times, the leading edge of the paper P reaches the paper discharge unit 6 (the paper P becomes the paper discharge roller). 55 and the paper discharge side driven roller 56).

  After the leading edge of the paper P reaches the paper discharge unit 6, the paper P is transported by the transport roller 41 and the paper discharge roller 55. The transport roller 41 and the paper discharge roller 55 are controlled to rotate in synchronization. If the carrying operation is continued several times in this state, the rear end of the paper P passes through an optical sensor 37 described later and the carrying roller 41 also passes through.

  After the trailing edge of the paper P passes through the transport roller 41, the rotation amount of the paper discharge roller 55 is controlled by the controller 10, and the paper P is transported while the position of the paper P with respect to the head 48 is controlled. That is, the paper P is conveyed by the paper discharge roller 55. When the printing of the image on the paper P is completed, the controller 10 further rotates the paper discharge roller 55 to discharge the paper P.

  As will be described later, the paper P can be transported in the reverse direction (reverse transport) by rotating the transport roller 41 and the paper discharge roller 55 in the reverse direction. When the paper P is fed to the reversing unit 100 to reverse it, the paper P is reversely conveyed. In addition, when reverse conveyance is started when the rear end of the paper P passes through the transport roller 41 and is on the platen 45, the rear end of the paper P passes through the transport roller 41 and then passes through the optical sensor 37. Will do. In this case, if the reverse conveyance is further continued, the leading edge of the paper P passes through the paper discharge roller 55, passes through the conveyance roller 41, and then passes through the optical sensor 37.

<Inversion>
FIG. 6 is an explanatory diagram of the inversion path.
The paper P reversely conveyed from the conveyance unit 5 is supplied to the reversing unit 100. The paper P supplied to the reversing unit 100 is guided to the upper left side in the drawing by a flip mechanism (not shown) and reaches the first roller 102. The first roller 102 is configured to rotate in synchronization with the transport roller 41. The rotation amount of the first roller 102 is controlled by the controller 10, and the paper P is supplied to the second roller 104. The second roller 104 is configured to rotate in synchronization with the first roller 102. That is, the rotation amount of the second roller 104 is also controlled by the controller 10. When the second roller 104 rotates, the paper P pushes down the hopper 49, and the paper P is guided to the right side in the drawing by the upper surface of the hopper 49. The paper P guided by the upper surface of the hopper 49 passes through an optical sensor 37 described later and reaches the transport unit 5 while being guided by the upper guide 43 or the lower guide 44.

  Before being supplied to the reversing unit 100, an image is printed on the upper surface (front surface) of the paper P in the drawing. When the paper P reaches the transport unit 5 after being supplied to the reversing unit 100, the printed surface (front surface) is on the lower side in the drawing, and the back surface of the paper P is on the upper side in the drawing. Yes. In the following description, the upper surface in the figure of the paper P before reversal is referred to as “front surface”, and the upper surface in the figure of the paper P after reversal is referred to as “back surface”.

  The leading edge of the paper P when printing the front side becomes the trailing edge of the paper P when printing the back side. Further, the rear end of the paper P when the front side is printed becomes the front end of the paper P when the back side is printed. In the following description, after the paper P is supplied from the reversing unit 100 to the transport unit 5, the leading edge of the paper P at that time (the trailing edge of the paper P at the time of front side printing) is referred to as “leading edge”. In other words, the tail of the paper P at that time (the front edge of the paper P at the time of front side printing) is referred to as “rear edge”.

  In the following description, regardless of before and after inversion, in the following description, when the paper P is sent from the paper feed unit side to the transport unit side, or when the paper P is sent from the reverse unit side to the transport unit side, or the paper P is transported When the paper is sent from the unit side to the paper discharge unit side, it is called “forward conveyance”. Conversely, when the paper P is sent from the transport unit side to the reversing unit side, or when the paper P is sent from the paper discharge unit side to the transport unit side is called “reverse transport”.

=== Optical Sensor 37 ===
<Shape of optical sensor 37>
FIG. 7 is an explanatory diagram of the optical sensor 37 viewed from the sheet feeding side. The thick line in the figure is the optical sensor 37. The diagonal lines in the figure are the sides of the paper P.

  The optical sensor 37 has a U shape (C shape). That is, the optical sensor 37 includes an upper protruding portion 37a, a lower protruding portion 37b, and a support portion 37c. The upper protruding portion 37a is provided with a light receiving portion 371, and the lower protruding portion 37b is provided with a light emitting portion 372. The light receiving unit 371 is provided on the light emitting unit 372 and detects light from the light emitting unit 372.

  Since the light receiving unit 371 is provided on the upper side and the light receiving surface of the light receiving unit 371 faces downward, dust does not accumulate on the light receiving surface and stable detection can be performed. In order to maintain the accuracy of the positional relationship between the light receiving portion 371 and the light emitting portion 372, the upper protruding portion 37a and the lower protruding portion 37b are integrally formed via the support portion 37c (for this reason, the optical sensor 37 is It becomes a U-shaped).

<Detection by optical sensor 37>
Here, when the light receiving unit 371 detects light from the light emitting unit 372, the optical sensor 37 outputs an H level signal. When the light receiving unit 371 does not detect light from the light emitting unit 372, the optical sensor 37 outputs an L level signal. When the paper P is at the position of the optical sensor 37, the paper P blocks the optical axis of the optical sensor 37, the light receiving unit 371 cannot detect the light from the light emitting unit 372, and the optical sensor 37 outputs an L level signal. . Accordingly, the controller 10 can detect the presence or absence of the paper P at the position of the optical sensor 37 based on the output of the optical sensor 37.

  Further, as described below, the controller 10 can detect the position of the end portion of the paper P based on the timing of the change in the output of the optical sensor 37.

  FIG. 8A is an explanatory diagram of detection of the leading edge of the paper P during forward conveyance (viewed from above). As shown in the figure, when the leading edge of the paper P passes through the optical sensor 37, the output of the optical sensor 37 changes from H level to L level. For this reason, the controller 10 can detect the leading edge of the paper P when the output of the optical sensor 37 changes from the H level to the L level during forward conveyance.

  FIG. 8B is an explanatory diagram of detection of the trailing edge of the paper P during forward conveyance. As shown in the figure, when the trailing edge of the paper P passes through the optical sensor 37, the output of the optical sensor 37 changes from L level to H level. For this reason, the controller 10 can detect the trailing edge of the paper P when the output of the optical sensor 37 changes from L level to H level during forward conveyance.

  FIG. 8C is an explanatory diagram of detection of the trailing edge of the paper P during reverse conveyance. As shown in the figure, when the trailing edge of the paper P passes through the optical sensor 37, the output of the optical sensor 37 changes from the H level to the L level. For this reason, the controller 10 can detect the trailing edge of the paper P when the output of the optical sensor 37 changes from the H level to the L level during reverse conveyance.

  FIG. 8D is an explanatory diagram of detection of the leading edge of the paper P during reverse conveyance. As shown in the figure, when the leading edge of the paper P passes through the optical sensor 37, the output of the optical sensor 37 changes from L level to H level. For this reason, the controller 10 can detect the leading edge of the paper P when the output of the optical sensor 37 changes from the L level to the H level during reverse conveyance.

=== Lower guide 44 ===
9A and 9B are explanatory diagrams of a comparative example. In order for the paper P guided by the lower guide 44 to pass between the upper protruding portion 37 a and the lower protruding portion 37 b of the optical sensor 37, it is necessary to embed the lower protruding portion 37 b in the lower guide 44. On the other hand, in order for the light receiving unit 371 to receive the light from the light emitting unit 372, it is necessary to expose the upper surface of the light emitting unit 372 from the lower guide 44. Here, just by embedding the lower protrusion 37b in the lower guide 44 while exposing the upper surface of the lower protrusion 37b as in the comparative example, the leading edge of the paper P is separated by the boundary between the lower guide 44 and the lower protrusion 37b. Passage may be hindered and paper jams may occur.

  FIG. 9C is an explanatory diagram of another comparative example. In this comparative example, in order to prevent the paper P from entering the boundary between the lower guide 44 and the lower protruding portion 37b when the paper P is conveyed in order, of the boundary between the lower guide 44 and the lower protruding portion 37b, The height on the downstream side in the conveying direction is lowered. However, in such a shape, when the paper P is reversely conveyed, the paper P enters the boundary between the lower guide 44 and the lower protruding portion 37b.

  Therefore, in the present embodiment, the lower projecting portion 37b is embedded in the lower guide 44 as follows. Further, according to the configuration of the present embodiment described below, paper jams can be prevented even during reverse conveyance.

  FIG. 10 is an explanatory diagram of the configuration of the lower guide 44. FIG. 11 is an explanatory diagram of the shape of the lower guide 44 around the optical sensor 37. Hereinafter, the lower guide 44 will be described with reference to these drawings.

  The lower guide 44 is provided with a plurality of ribs 44B. This rib is raised from the base surface 44A along the paper feeding direction. When the lower guide 44 guides the paper P, the paper P is supported by the ribs 44B. The ribs prevent the paper P from being attracted to the base surface 44A due to static electricity or the like.

  The optical sensor 37 described above is provided on the side end side of the lower guide 44. The lower protruding portion 37b of the optical sensor 37 is inserted into the lower guide 44 (an insertion portion for inserting the lower protruding portion 37b is provided in the lower guide 44). The optical sensor 37 is fixed to the lower guide 44 at the support portion 37c.

  The upper surface of the lower protruding portion 37b of the optical sensor 37 is covered with a raised portion 44C of the lower guide 44 (except for a portion above the light emitting portion 372). A slope is formed between the raised portion 44C and the base surface 44A. By configuring the raised portion 44C in this way, it is possible to prevent the front end of the paper P (the rear end during reverse conveyance) from entering the boundary between the lower guide 44 and the lower protruding portion 37b.

Further, the lower guide 44 is provided with an opening 44D. The light emitting portion 372 of the optical sensor 37 is positioned below the opening 44D, and the optical axis of the optical sensor 37 passes through the opening 44D. That is, the lower protrusion 37b of the optical sensor 37 is exposed at the opening 44D. The opening 44D is provided on the base surface between the rib 44B and the rib 44B. By providing the opening 44D at such a position, it is possible to prevent the front end of the paper P (the rear end during reverse conveyance) from entering the boundary between the lower guide 44 and the lower protrusion 37b. (Note that if the opening 44D is provided in the rib 44B, the leading edge (or the trailing edge) of the paper P may enter the boundary between the rib 44B and the lower protrusion 37b.)
The height of the raised portion 44C is the same as the height of the rib 44B. Thereby, it is possible to prevent the front end of the paper P (the rear end during reverse conveyance) from entering the boundary between the rib 44B and the raised portion 44C. Further, the surface of the raised portion 44 </ b> C is higher than the upper surface of the lower protruding portion 37 b of the optical sensor 37. Thereby, it is possible to prevent the front end of the paper P (the rear end during reverse conveyance) from entering the boundary between the lower guide 44 and the lower protruding portion 37b.

  The height of the base surface 44A and the upper surface of the lower protrusion 37b of the optical sensor 37 may be different. In the present embodiment, the upper surface of the lower protrusion 37b is higher than the base surface 44A (see also FIG. 17). Thereby, the distance between the light emitting unit 372 and the light receiving unit 371 can be shortened as much as possible, and the detection accuracy of the optical sensor 37 can be increased.

  By the way, when the paper P is fed, the side of the paper P is guided by the lateral guide surface 44E of the lower guide 44 regardless of the size of the paper P. The lateral guide surface 44E is provided closer to the paper side than the inner surface of the support portion 37c of the optical sensor 37. With this configuration, it is possible to prevent the side of the paper P from coming into contact with the inner surface of the support portion 37c of the optical sensor 37 (the side edge (side) of the paper P in FIG. 7 and the support. (See also the positional relationship with the portion 37c). Thereby, it is possible to prevent the front end of the paper P (the rear end during reverse conveyance) from entering the boundary between the inner surface of the support portion 37 c of the optical sensor 37 and the lower guide 44.

=== Upper guide 43 ===
<Configuration of peripheral members of upper guide 43>
FIG. 12 is an explanatory diagram of the upper guide unit 9 having the upper guide 43. FIG. 13 is an explanatory diagram of the periphery of the upper guide unit 9 as viewed from the platen side. FIG. 14 is an explanatory diagram of the periphery of the upper guide unit 9 as viewed from the sheet feeding side. Hereinafter, the upper guide 43 will be described with reference to FIG.

  The upper guide unit 9 is a unit for attaching the upper guide 43 and the conveyance-side driven roller 42 to the apparatus main body so as to be swingable. The upper guide unit 9 includes a sub-frame 8, a swing shaft 31, a first coil spring 32, a second coil spring 33, and a roller shaft 34 in addition to the above-described upper guide 43 and the conveyance-side driven roller 42.

  The subframe 8 is formed by bending a metal plate material. The sub frame 8 is attached to the main frame 7 of the apparatus main body. The subframe 8 is formed with hooks 8a and 8b, a tongue piece portion 8c, and bearing portions 8f and 8g. The hooks 8 a and 8 b are for hooking on a fastening portion 7 b (see FIG. 13) provided on the main frame 7. The tongue piece 8c is formed with a boss 8d and a long hole 8e. The boss 8 d of the tongue piece 8 c is inserted into the hole 7 a of the main frame 7. The long hole 8 e is a hole for fixing the subframe with the fixing screw 35 in the hole 7 c of the main frame 7. The bearing portions 8 f and 8 g are bearings for supporting the swing shaft 31.

  The swing shaft 31 is a shaft that supports the upper guide 43 so as to be swingable with respect to the subframe 8. The swing shaft 31 is supported by the subframe 8 via the bearing portions 8f and 8g, and supports the upper guide 43 through a shaft hole provided in the upper guide 43 so as to be swingable. The upper guide 43 swings by the thickness of the paper.

  The first coil spring 32 gives a rotational force about the swing shaft 31 between the subframe 8 and the upper guide 43. With this rotational force, the upper guide 43 is given a rotational force in the direction of lowering the conveyance-side driven roller 42 around the swing shaft 31. For this purpose, the swing shaft 31 is located at the coil center of the first coil spring 32, one end of the first coil spring 32 is hooked on the subframe 8 via the hook portion 8h, and the other end holds the upper guide 43 from the upper surface. ing.

  The second coil spring 33 gives a rotational force about the swing shaft 31 between the subframe 8 and the roller shaft 34. With this rotational force, the roller shaft 34 is stabilized on the upper guide 43, and the rotational force in the direction of lowering the conveyance-side driven roller 42 around the rocking shaft 31 via the roller shaft 34. Is given. For this purpose, the swinging shaft 31 is positioned at the coil center of the second coil spring 33, one end of the second coil spring 33 is hooked on the subframe 8 via the hook portion 8h, and the other end of the roller shaft 34 from above. Holding down.

  The roller shaft 34 is a shaft that rotatably supports the conveyance-side driven roller 42. The roller shaft 34 is supported by the upper guide 43. By applying a spring force from the second coil spring 33 from above, the roller shaft 34 is supported so as not to be detached from the upper guide 43.

<Seal member>
The upper guide 43 needs to guide the paper P so that it can pass through the optical sensor 37. Therefore, the upper guide 43 is provided with a recess 43a, and the upper protrusion 37a of the optical sensor 37 enters the recess 43a. As a result, the paper P guided by the upper guide 43 passes under the upper projecting portion 37a of the optical sensor 37 entering the concave portion 43a.

  On the other hand, as in the case of FIG. 9B described above, when the upper guide 43 guides the paper P, the leading edge of the paper P at the boundary between the upper guide 43 and the upper protruding portion 37a of the optical sensor 37 (the rear edge during reverse conveyance). ) Must be prevented from entering. However, since the upper guide 43 is supported so as to be swingable with respect to the main frame 7 and the optical sensor 37 is fixed to the lower guide 44, the upper guide 43 is an upper protruding portion of the optical sensor 37. The posture changes relative to 37a. That is, it is necessary to prevent the front end of the paper P (the rear end at the time of reverse conveyance) from entering the boundary between the upper guide 43 and the upper projecting portion 37a whose posture changes relatively.

  Therefore, in the present embodiment, the boundary between the upper guide 43 and the upper protruding portion 37a is covered by the seal member 38, and the leading end of the paper P (the rear end during reverse conveyance) enters the boundary between the upper guide 43 and the upper protruding portion 37a. To prevent that. Hereinafter, the seal member 38 will be described.

FIG. 15A to FIG. 15C are explanatory views showing how the seal member 38 is attached to the upper guide 43.
The seal member 38 is a flexible sheet-like (or film-like) member, specifically a PET film. Holes 38 a and 38 b are formed near both ends of the seal member 38. A hook 43d is provided above the recess 43a of the upper guide 43, and one hole 38a is hooked on the hook 43d, wound through the through hole 43f, and the other hole 38b is hooked on the hook 43d. Thus, the seal member 38 is attached to the upper guide 43. The upper guide 43 is provided with a tension applying portion 43e, and the tension applying portion 43e prevents the seal member 38 from being bent.

FIG. 16 is an explanatory diagram showing a state in which the upper protruding portion 37a enters the recessed portion 43a. FIG. 17 is a cross-sectional view for explaining the relationship between the seal member 38 and the upper protruding portion 37a.
When the seal member 38 is wound around the upper guide 43, a space surrounded by the recess 43a and the seal member 38 is formed. The upper protrusion 37a of the optical sensor 37 enters the space.

  As can be understood from FIG. 17, the boundary between the upper guide 43 and the upper projecting portion 37a is sealed by the seal member 38. Thereby, it is possible to prevent the front end of the paper P (the rear end during reverse conveyance) from entering the boundary between the upper guide 43 and the upper protruding portion 37a. Even if the upper guide 43 swings and the upper projecting portion 37a and the seal member 38 come into contact with each other, the seal member 38 is deformed and the upper guide 43 is deformed because the seal member 38 is made of a flexible material. And the state where the boundary between the upper protrusion 37a is sealed.

  Further, since the sealing member 38 is wound around and attached to the upper guide 43, both of the boundaries between the upper guide 43 and the upper projecting portion 37a (the boundary between the upper guide 43 and the upper projecting portion 37a on the through hole 43f side). And the boundary between the upper guide 43 and the upper projecting portion 37a on the tension applying portion 43e side can be sealed by the seal member. Thereby, it is possible to prevent the front end of the paper P (the rear end at the time of reverse conveyance) from entering the boundary between the upper guide 43 and the upper protruding portion 37a during forward conveyance and reverse conveyance.

  A portion of the seal member 38 that closes the concave portion 43 a is located between the upper protruding portion 37 a and the lower protruding portion 37 b of the optical sensor 37. This portion of the seal member 38 may be formed so as to avoid the optical axis region of the optical sensor 37 or may be formed so as to block the optical axis region. If the sealing member 38 is formed so as to avoid the optical axis region of the optical sensor 37, the sealing member 38 may be made of a light shielding material. On the other hand, if the seal member 38 is formed so as to block the optical axis region of the optical sensor 37, the seal member 38 needs to be made of a translucent material.

=== Platen 45 ===
FIG. 18 is a view of the platen 45 viewed from an oblique direction. In order to simplify the configuration in the figure, the upper guide unit 9 is removed here. The platen 45 is formed with an upstream convex portion 45a, a central convex portion 45b, and a downstream convex portion 45c. The platen 45 is fitted with a sponge 58 for absorbing ink. The sponge 58 is an ink absorber for absorbing ink that has not landed on the paper P during borderless printing.

FIG. 19A is an explanatory diagram during borderless printing of the leading edge of the paper P. FIG. As shown in the drawing, the platen 45 is provided with an upstream groove 45d and a downstream groove 45e, and the sponge 58 is fitted into the upstream groove 45d and the downstream groove 45e. The upstream groove 45d is provided between the upstream convex part 45a and the central convex part 45b, and the downstream groove part 45e is provided between the central convex part 45b and the downstream convex part 45c.
When printing the front end of the paper P without borders, the controller 10 first transports the paper P by rotating the transport roller 41 so that the front end of the paper P is positioned on the downstream side groove 45e. In this state, the controller 10 ejects ink from the head 48 to form an image on the leading edge of the paper P. At this time, ink droplets that have not landed on the paper P land on the sponge 58 of the downstream groove 45e.

FIG. 19B is an explanatory diagram at the time of borderless printing of the trailing edge of the paper P.
When borderless printing is performed on the trailing edge of the paper P, ink droplets are ejected from the head 48 in a state where the trailing edge of the paper P is positioned on the upstream groove 45d, and an image is formed on the trailing edge of the paper P. . At this time, ink droplets that have not landed on the paper P land on the sponge 58 in the upstream groove 45d.

FIG. 19C is an explanatory diagram at the time of borderless printing of the side edge of the paper P. As shown in the figure, the platen 45 is provided with a side groove 45f, and the sponge 58 is fitted in the side groove 45f.
When printing the standard size paper P, the side edge (side) of the paper P is positioned on the side groove 45f. In such a state, ink droplets are ejected from the head 48 in a range wider than the paper width, and an image is formed over the entire width of the paper P. At this time, ink droplets that have not landed on the paper P land on the sponge 58 of the side groove 45f.

  By the way, as shown to FIG. 19A and FIG. 19B, the conveyance direction upstream of the upstream convex part 45a, the center convex part 45b, and the downstream convex part 45c is a slope. The reason why the slope is formed in the convex portion in this way is to prevent the leading end of the paper P from being caught in the convex portion and being jammed when the paper P is conveyed.

  On the other hand, as shown in FIGS. 19A and 19B, the upstream side of the upstream convex portion 45a, the central convex portion 45b, and the downstream convex portion 45c in the transport direction is not inclined. If the convex portion downstream in the transport direction is inclined, the leading edge of the paper P is likely to come into contact with the sponge 58 and the back surface of the paper P may be soiled.

=== Operations for double-sided printing ===
FIG. 20 is a flowchart for double-sided printing according to this embodiment. In the double-sided printing of this embodiment, it is assumed that one side is “printed with a border” and the other side is “printed without a border”. For example, when printing a New Year's card, if you print an address, address, etc. on one side and print a photo on the other side, one side will be "print with borders" and the other side will be "prints without borders" It becomes.

  First, the controller 10 determines a printing surface (S001). Specifically, it is determined that an image with a border is printed on the front surface of the paper P and an image without a border is printed on the back surface. For example, when printing a New Year's card, the controller 10 determines to print an address / address on the front side of the paper P and print a photo on the back side. In order to enable printing in this order, the controller 10 displays a postal setting direction on a display unit (not shown) (liquid crystal panel or the like). In the case of rear paper feeding, set the address / address to be printed on the top, and in the case of front paper feeding, set the photo printing side to be on the front side. You can print the address, address, etc., and print the photo on the back.

  Next, the controller 10 performs a paper feed process. The paper feed processing is performed by the controller 10 rotating the rear paper feed roller 11 in the case of rear paper feed and the front paper feed roller 28 in the case of front paper feed by a predetermined amount (S002, FIG. 3). (See FIG. 4).

  If the paper feeding process is normally performed, the leading edge of the paper P reaches the optical sensor 37, and the optical sensor 37 detects the leading edge of the paper P (YES in S003). If the optical sensor 37 does not detect the leading edge of the paper P even though the controller rotates the rear paper feeding roller 11 or the front paper feeding roller 28 by a predetermined amount (NO in S003), the controller 10 The occurrence of a jam (paper jam) in the unit is detected (S101). In this case, the controller 10 displays on the display means (liquid crystal panel or the like) (not shown) that a jam has been detected and the location where the jam has occurred (in this case, the paper feed unit).

  When the optical sensor 37 detects the leading edge of the paper P (YES in S003), the controller 10 transports the paper P by a predetermined amount from there and transports the paper P to the print start position (heading position) (this position). The process is referred to as “heading process”) (S004). The transport amount from when the optical sensor 37 detects the leading edge of the paper P to when the paper P is transported to the print start position is determined in advance. As described above, the controller 10 performs a cueing process based on the detection result of the optical sensor 37. After the head setting process, the paper P is in a state of facing the head 48.

  Next, the controller 10 starts printing with the front edge of the paper P (S005). At this time, the controller 10 alternately repeats a dot forming operation for forming ink on the paper P by ejecting ink from the head 48 while the carriage 46 is moving, and a transporting operation for transporting the paper P by a predetermined transport amount. . If the transport operation is continued several times, the rear end of the paper P reaches the optical sensor 37.

  When the optical sensor 37 does not detect the trailing edge of the paper P despite the predetermined number of times of carrying operation (NO in S006), the controller 10 detects the occurrence of a jam in the vicinity of the carry roller 41. (S102). In this case, the controller 10 displays on the display means (not shown) such as a liquid crystal panel that the jam has been detected and the location where the jam has occurred (in this case, the vicinity of the transport roller).

After the optical sensor 37 detects the trailing edge of the paper P (YES in S006), the bordered printing is continued for a while and the printing on the front surface is finished (S007).
FIG. 21 is an explanatory diagram of the position of the trailing edge of the paper P at the end of front surface printing. As shown in the figure, the rear end of the paper P is supported by the upstream convex portion 45a. Alternatively, the rear end of the paper P may be on the upstream side (the left side in the drawing) with respect to the upstream convex portion 45a. However, in the present embodiment, it is prohibited that the rear end of the paper P is located downstream of the upstream convex portion 45a (right side in the drawing) when the front surface printing is finished. In other words, in this embodiment, the controller 10 controls the printing process with the front edge of the front surface so that the rear end of the paper P does not become downstream from the upstream convex portion 45a when the front surface printing is finished. ing. Note that the controller 10 stores the transport amount from when the optical sensor 37 detects the trailing edge of the paper P to when the bordered printing process ends.

  Next, the controller 10 starts the inversion process (S008). When reverse conveyance is performed from the state of FIG. 21, the trailing edge of the paper P passes through the conveyance roller 41 and then passes through the optical sensor 37.

  If the optical sensor 37 does not detect the trailing edge of the paper P (NO in S010) even though the predetermined amount of reverse conveyance has been performed (S009), the controller 10 detects the occurrence of a jam on the conveyance roller 41. (S103). In this case, it is assumed that the trailing edge of the paper P cannot pass through the transport roller 41. The predetermined amount serving as a reference in S009 is set according to the carry amount stored in S007. The larger the transport amount stored in S007, the larger the reference predetermined amount is set. The controller 10 displays on the display means (not shown) such as a liquid crystal panel that the jam has been detected and the location where the jam has occurred (in this case, the transport roller).

  After the optical sensor 37 detects the trailing edge of the paper P (YES in S010), the controller 10 further performs a predetermined amount of reverse conveyance (S011). If the optical sensor 37 does not detect the leading edge of the paper P even though a predetermined amount of reverse conveyance has been performed (NO in S012), the controller 10 detects a jam in the vicinity of the conveyance roller (S104). In this case, the controller 10 displays on the display means (not shown) such as a liquid crystal panel that the jam has been detected and the location where the jam has occurred (in this case, the vicinity of the transport roller).

  When the optical sensor 37 detects the leading edge of the paper P (YES in S012), it is assumed that the paper P is supplied to the reversing unit 100. Then, the controller 10 performs a predetermined amount of inversion operation (S013). That is, the controller 10 rotates the first roller 102 and the second roller 104 by a predetermined rotation amount. When a predetermined amount of reversing operation is performed, the leading edge of the paper P (the trailing edge during front surface printing) reaches the optical sensor 37.

  If the optical sensor 37 does not detect the leading edge of the paper P (NO in S014) even though a predetermined amount of reversing operation has been performed (S013), the controller 10 detects the occurrence of a jam in the reversing unit 100. (S105). In this case, it is assumed that the paper P is jammed inside the reversing unit 100. The controller 10 displays on the display means (not shown) such as a liquid crystal panel that the jam has been detected and the location where the jam has occurred (in this case, the inside of the reversing unit).

  After the optical sensor 37 detects the leading edge of the paper P (YES in S014), the controller 10 performs a cueing process for back side printing (S015). Since the borderless printing is performed in the back side printing, the leading edge of the paper P after the head setting process is positioned on the downstream side groove 45e (see FIG. 19A).

  Next, the controller 10 starts borderless printing on the back surface of the paper P (S016). At this time, the controller 10 alternately repeats a dot forming operation for forming ink on the paper P by ejecting ink from the head 48 while the carriage 46 is moving, and a transporting operation for transporting the paper P by a predetermined transport amount. . Note that when borderless printing is performed on the leading edge of the paper P, ink droplets that do not land on the paper P land on the sponge 58 in the downstream groove 45e (see FIG. 19A). When borderless printing is performed on the side edge of the paper P, ink droplets that do not land on the paper P land on the sponge 58 in the side groove 45f (see FIG. 19C). If the conveying operation is continued several times during printing without borders on the back surface, the trailing edge of the paper P reaches the optical sensor 37.

  If the optical sensor 37 does not detect the trailing edge of the paper P despite the predetermined number of times of carrying operation (NO in S017), the controller 10 detects the occurrence of a jam near the carrying roller 41. (S106). In this case, the controller 10 displays on the display means (not shown) such as a liquid crystal panel that the jam has been detected and the location where the jam has occurred (in this case, the vicinity of the transport roller).

  After the optical sensor 37 detects the trailing edge of the paper P (YES in S017), the controller 10 limits the ink ejection range when printing the trailing edge of the paper P based on the detection result of the optical sensor 37. . If ink is ejected over a wide range, the ink is wasted and the sponge in the upstream groove 45d is wasted, so that the ink is ejected only in an appropriate range according to the position of the detected rear end. To. Note that when borderless printing is performed on the trailing edge of the paper P, ink droplets that do not land on the paper P land on the sponge 58 in the upstream groove 45d (see FIG. 19B).

  After the borderless printing on the back surface is completed (S019), the controller 10 performs a paper discharge process and ends the duplex printing.

<Comparative Example 1>
FIG. 22 is an explanatory diagram of a paper edge detection sensor in a comparative example. The paper edge detection sensor 70 of this comparative example includes a lever 70a, a light shielding part 70b, and a sensor part 70c. When the leading edge of the paper P reaches the paper edge detection sensor, the leading edge of the paper P pushes up the lever 70a, the light shielding portion 70b rotates, and the light shielding portion 70c enters between the light emitting portion and the light receiving portion (not shown) of the sensor portion 70c. Thus, the paper edge detection sensor 70 detects the leading edge of the paper P. When the rear end of the paper P passes through the lever 70a, the lever 70a returns to the original position, and the paper end detection sensor 70 detects the rear end of the paper P.

According to such a comparative example, it is not necessary to guide the paper P between the light receiving unit 371 and the light emitting unit 372 as in the case of using the optical sensor 37 of the present embodiment. unnecessary.
However, the paper edge detection sensor 70 of the comparative example can detect the paper edge only when the paper P is transported in the forward direction, and cannot detect the paper edge when the paper P is transported in the reverse direction.

  In contrast to such a comparative example, according to the optical sensor 37 of the present embodiment, the leading edge and the trailing edge of the paper P are detected in a non-contact manner. It can be detected. In the above-described embodiment, by using such an optical sensor 37, the trailing edge of the paper P is detected during reverse conveyance to detect a jam on the conveyance roller (see S010 and S103 in FIG. 20). ), The leading edge of the paper P can be detected during reverse conveyance to detect a jam near the conveyance roller (see S012 and S104 in FIG. 20).

<Comparative Example 2>
23A and 23B are explanatory diagrams of front surface printing of a comparative example. In this comparative example, borderless printing is performed in front side printing at the time of duplex printing.
As described with reference to FIG. 19B, when the trailing edge of the paper P is printed without a border, the trailing edge of the paper P is positioned on the upstream groove 45d. For this reason, in the comparative example, after the front surface printing is finished, when the paper P is reversely conveyed to reverse it, the reverse conveyance starts in the state shown in FIG. 23A.
On the other hand, the downstream side in the transport direction of the upstream convex portion 45a is not inclined (to prevent the tip of the paper P from contacting the sponge 58). For this reason, when reverse conveyance is performed from the state of FIG. 23A, the rear end of the paper P is caught on the upstream convex portion 45a as shown in FIG.

  In contrast to such a comparative example, in this embodiment, borderless printing is performed by backside printing, and “frontside printing” is performed by front side printing. For this reason, a paper jam as shown in FIG. 23B can be prevented.

=== Other Embodiments ===
The above-described embodiment is mainly described for a printer. Among them, a printing apparatus, a recording apparatus, a liquid ejection apparatus, a printing method, a recording method, a liquid ejection method, a printing system, a recording system, and a computer system are included. Needless to say, the disclosure includes a program, a storage medium storing the program, a display screen, a screen display method, a printed material manufacturing method, and the like.

  Moreover, although the printer etc. as one embodiment were demonstrated, said embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof.

<About the printer>
In the above-described embodiment, the printer has been described. However, the present invention is not limited to this. For example, color filter manufacturing apparatus, dyeing apparatus, fine processing apparatus, semiconductor manufacturing apparatus, surface processing apparatus, three-dimensional modeling machine, liquid vaporizer, organic EL manufacturing apparatus (particularly polymer EL manufacturing apparatus), display manufacturing apparatus, film formation The same technique as that of the present embodiment may be applied to various recording apparatuses to which an ink jet technique is applied such as an apparatus and a DNA chip manufacturing apparatus.

<About ink>
Since the above-described embodiment is an embodiment of a printer, dye ink or pigment ink is ejected from the nozzle. However, the liquid ejected from the nozzle is not limited to such ink. For example, liquids (including water) including metal materials, organic materials (especially polymer materials), magnetic materials, conductive materials, wiring materials, film-forming materials, electronic inks, processing liquids, gene solutions, etc. are ejected from nozzles. May be.

<About nozzle>
In the above-described embodiment, ink is ejected using a piezoelectric element. However, the method for discharging the liquid is not limited to this. For example, other methods such as a method of generating bubbles in the nozzle by heat may be used.

=== Summary ===
(1) The above-described printing apparatus 1 (an example of a recording apparatus) includes a transport unit 5 and a paper discharge unit 6 (an example of a transport mechanism), a head 48, an optical sensor 37, and a reversing unit 100 (an example of a reversing mechanism). And a controller 10. When the controller 10 prints the front surface of the medium, the controller 10 causes the transport unit 5 and the paper discharge unit 6 to transport the paper P (an example of the medium) in the forward direction (transported in the forward direction) and the optical sensor 37. The edge of the paper P is detected.

Here, if a sensor such as that shown in FIG. 22 is used, the edge of the forwardly transported paper can be detected, but the end of the reversely transported paper cannot be detected.
Therefore, in the above-described embodiment, the optical sensor 37 that can detect the presence or absence of paper (an example of a medium) in a non-contact manner is employed. Accordingly, the controller 10 detects the optical sensor when the paper P is reversely conveyed (conveyed in the reverse direction) to the conveyance unit 5 and the paper discharge unit 6 in order to reverse the paper P to the reversing unit 100 after recording the front surface. 37 makes it possible to detect the edge of the paper P.

(2) According to the above-mentioned embodiment, the optical sensor 37 has the light emission part 372 and the light-receiving part 371 (refer FIG. 7). In the case of using such a sensor, it is desirable to shorten the distance between the light emitting unit 372 and the light receiving unit 371 in order to increase detection accuracy. On the other hand, it is necessary to pass the paper P between the light emitting unit 372 and the light receiving unit 371.
Therefore, the printer 1 described above includes a lower guide 44 and an upper guide 43 for guiding paper between the light emitting unit 372 and the light receiving unit 371. This makes it possible to reduce the distance between the light emitting unit 372 and the light receiving unit 371 and to allow the paper P to pass between the light emitting unit 372 and the light receiving unit 371.

(3) The optical sensor 37 includes an upper protruding portion 37a and a lower protruding portion 37b. The upper protruding portion 37a includes a light receiving portion 371, and the lower protruding portion 37b includes a light emitting portion 372 (see FIG. 7). Here, as shown in FIG. 9B, if the lower protrusion 37b is embedded in the lower guide 44, the paper P may be caught at the boundary between the lower guide 44 and the lower protrusion 37b. Therefore, the lower guide 44 is provided with an insertion portion for inserting the lower protruding portion, and an opening 44D is provided at the position of the optical axis of the optical sensor 37.
On the other hand, the lower guide 44 is provided with a base surface 44A and a rib 44B (see FIG. 11). If an opening is provided in the rib 44B, the leading edge of the paper P may be caught on the boundary as in the case of FIG. 9B.
Therefore, in the above-described embodiment, the opening 44D is provided on the base surface 44A between the rib 44B and the rib 44B. Since the paper P contacts the rib 44B and does not contact the base surface between the rib 44B and the rib 44B, there is no possibility that the paper P is caught on the boundary between the base surface 44A and the lower protruding portion 37b. Clogging can be prevented.

  In the above-described embodiment, the upper protruding portion 37a includes the light receiving portion 371 and the lower protruding portion 37b includes the light emitting portion 372, but the reverse may be possible. However, when the light receiving unit 371 is on the upper side, dust is not collected on the light receiving surface, and stable detection can be performed.

(4) Since the optical sensor 37 detects the presence or absence of the paper P when the light receiving unit 371 detects the light from the light emitting unit 372, the detection accuracy of the optical sensor 37 is determined by the distance between the light emitting unit 372 and the light receiving unit 371. The shorter the better. Therefore, in the above-described embodiment, the upper surface of the lower protrusion 37b is configured to be positioned above the base surface 44A of the lower guide 44 (see FIG. 17). Thereby, the distance between the light emitting unit 372 and the light receiving unit 371 can be shortened as much as possible, and the detection accuracy of the optical sensor 37 can be increased.

(5) The lower guide 44 has a raised portion 44C for covering the lower protruding portion 37b (see FIG. 11). Thereby, the part which the boundary of the lower guide 44 and the lower protrusion part 37b exposes can be decreased. In addition, a slope is formed between the raised portion 44C and the base surface 44A on the upstream side in the transport direction and the downstream side in the transport direction (see FIG. 11). Thereby, it is possible to prevent the paper P from being caught by the raised portion 44C in both cases of forward conveyance and reverse conveyance.

(6) In the above-described embodiment, the optical sensor 37 is fixed to the lower guide 44, and the upper guide 43 is provided so as to be swingable with respect to the lower guide 44. For this reason, the positional relationship between the upper guide 43 and the upper protrusion 37a of the optical sensor 37 changes. Specifically, the positional relationship between the upper guide 43 and the upper protruding portion 37 a of the optical sensor 37 changes before and after the paper P is sandwiched between the transport roller 41 and the transport-side driven roller 41. On the other hand, it is also necessary to prevent the leading edge of the paper P from entering the boundary between the upper guide 43 and the upper protruding portion 37a of the optical sensor 37.
Therefore, in the above-described embodiment, the boundary between the upper projecting portion 37 a of the optical sensor 37 and the upper guide 43 is sealed by the flexible sealing member 38. Thereby, it is possible to prevent the leading end of the paper P from entering the boundary between the upper guide 43 and the upper protruding portion 37a whose posture changes relatively.

(7) In the above-described embodiment, the upstream convex portion 45a (an example of the first convex portion), the central convex portion 45b (an example of the second convex portion), and the upstream groove portion 45d (an example of the groove) are platen. 45. When the controller 10 performs borderless printing on the rear end, the controller 10 moves the paper P to the transport unit 5 and the paper discharge unit 6 so that the rear end of the paper P is positioned on the upstream groove 45d. 48, the trailing edge of the paper P is printed (see FIG. 19B).
However, if borderless printing is performed during front side printing, the rear end of the paper P may be caught by the upstream convex portion 45a during reverse conveyance, and the paper may be jammed.

Therefore, the controller described above causes the head 48 to transfer the paper P to the head 48 while transporting the paper P to the transport unit 5 and the paper discharge unit 6 so that the rear end of the paper P is not downstream in the transport direction with respect to the upstream convex portion. When printing the front surface and printing the back surface, the paper P is transported to the head 48 while the paper P is transported to the transport unit 5 and the paper discharge unit 6 so that the rear end of the medium is positioned on the upstream groove 45d. The rear end is printed (see FIG. 19B). That is, when the controller 10 performs double-sided printing on the paper P with a borderless image and a bordered image, the controller 10 performs borderless printing on the front surface and performs borderless printing on the back surface.
This makes it possible to reduce the possibility of a paper jam because the rear end of the paper P is not easily caught by the upstream convex portion during reverse conveyance after front surface printing.

(8) According to the printing method (an example of the recording method) described above, first, the paper P (an example of the medium) is fed to the transport unit 5 (an example of the transport mechanism), and the paper P is fed to the transport unit 5. The leading edge of the paper P is detected by an optical sensor 37 (an example of a non-contact sensor) before printing, and the front surface of the paper P is printed (an example of recording) while being transported in order by the transport unit 5 and the paper discharge unit 6. After the front surface printing, the paper P is reversely conveyed in order to reverse the paper P by the reversing unit 100 (an example of a reversing mechanism). Here, since the optical sensor 37 described above is a sensor that can detect the presence or absence of the paper P in a non-contact manner, the front and rear ends of the paper P can be detected during reverse conveyance.

It is the schematic of the side cross section of a printer. 1 is a block diagram of an overall configuration of a printer. It is explanatory drawing of a rear paper feed path | route. FIG. 6 is an explanatory diagram of a front paper feed path. 5A to 5C are explanatory diagrams of conveyance and paper discharge. It is explanatory drawing of an inversion path | route. It is explanatory drawing of the optical sensor 37 seen from the paper feed side. FIG. 8A is an explanatory diagram of detection of the leading edge of the paper P during forward conveyance. FIG. 8B is an explanatory diagram of detection of the trailing edge of the paper P during forward conveyance. FIG. 8C is an explanatory diagram of detection of the trailing edge of the paper P during reverse conveyance. FIG. 8D is an explanatory diagram of detection of the leading edge of the paper P during reverse conveyance. 9A and 9B are explanatory diagrams of a comparative example. FIG. 9C is an explanatory diagram of another comparative example. It is explanatory drawing of a structure of the lower guide. It is explanatory drawing of the shape of the lower guide 44 around the optical sensor 37. FIG. It is explanatory drawing of the upper guide unit 9 which has the upper guide 43. FIG. It is explanatory drawing of the periphery of the upper guide unit 9 seen from the platen side. FIG. 6 is an explanatory diagram of the periphery of the upper guide unit 9 as viewed from the sheet feeding side. FIG. 15A to FIG. 15C are explanatory views showing how the seal member 38 is attached to the upper guide 43. It is explanatory drawing of a mode that the upper protrusion part 37a has entered into the recessed part 43a. It is sectional drawing for demonstrating the relationship between the sealing member 38 and the upper protrusion part 37a. It is the figure which looked at the platen 45 from the diagonal. FIG. 19A is an explanatory diagram during borderless printing of the leading edge of the paper P. FIG. FIG. 19B is an explanatory diagram at the time of borderless printing of the trailing edge of the paper P. FIG. 19C is an explanatory diagram at the time of borderless printing of the side edge of the paper P. It is a flowchart at the time of double-sided printing of this embodiment. It is explanatory drawing of the position of the rear end of the paper P at the time of completion | finish of front surface printing. It is explanatory drawing of the paper edge detection sensor in a comparative example. 23A and 23B are explanatory diagrams of front surface printing of a comparative example.

Explanation of symbols

1 Printer, 2 Rear paper feed unit, 3 Front paper feed unit,
4 Carriage unit, 5 Transport unit, 6 Paper discharge unit,
7 Main frame, 7a hole, 7b clasp, 7c hole,
8 subframe, 8a hook, 8b hook,
8c tongue part, 8d boss, 8e long hole, 8f bearing part, 8g bearing part,
8h hook part, 9 upper guide unit,
10 controller, 11 rear feed roller, 12 hopper, 12a fulcrum,
13 retard roller, 14 return lever, 15 rear paper feed guide,
25 trays, 26 pickup rollers, 28 front paper feed rollers,
29 separation roller, 30 assist roller,
31 oscillating shaft, 32 first coil spring, 33 second coil spring, 34 roller shaft,
35 fixing screws,
37 optical sensor, 37a upper protrusion, 37b lower protrusion, 37c support,
38 sealing member, 38a hole, 38b hole,
41 Conveying roller, 42 Conveying side driven roller, 43 Upper guide,
43a recess, 43d hook, 43f through hole, 43e tension applying part,
44 Lower guide, 44A Base surface, 44B Rib, 44C Raised portion,
44D opening, 44E lateral guide surface,
45 platen, 45a upstream convex part, 45b central convex part, 45c downstream convex part,
45d upstream groove, 45e downstream groove, 45f side groove,
46 Carriage, 47 axes, 48 heads, 49 Hoppers,
55 discharge roller, 56 discharge side driven roller, 57 auxiliary roller, 58 sponge,
100 reversing unit, 102 first roller, 104 second roller,
371 Light receiving part, 372 Light emitting part, P paper

Claims (8)

(A) a transport mechanism for transporting the medium in the forward direction and the reverse direction;
(B) a head for recording dots on the medium;
(C) a sensor for detecting the presence or absence of the medium in a non-contact manner;
(D) a reversing mechanism for reversing the medium;
(D) a controller that detects the edge of the medium by the sensor when the transport mechanism transports the medium in the forward direction in order to cause the head to record the front surface of the medium;
A controller that detects the edge of the medium by the sensor when the medium is conveyed in the reverse direction by the conveying mechanism to cause the reversing mechanism to invert the medium after recording the front surface;
A recording apparatus comprising: The recording apparatus according to claim 1,
The sensor has a light emitting part and a light receiving part,
The recording apparatus further includes a lower guide and an upper guide for guiding the medium between the light emitting unit and the light receiving unit. The recording apparatus according to claim 2,
The sensor has an upper protrusion and a lower protrusion,
The upper protruding portion includes one of the light emitting portion and the light receiving portion, and the lower protruding portion includes the other,
The lower guide has a base surface, a rib that is formed to rise from the base surface and contacts the medium, and an insertion portion for inserting the lower protrusion.
An opening is provided at the position of the optical axis of the sensor in the lower guide,
The recording apparatus according to claim 1, wherein the opening is provided in the base surface between the ribs. The recording apparatus according to claim 3,
The recording apparatus according to claim 1, wherein an upper surface of the lower protrusion is positioned above the base surface of the lower guide. The recording apparatus according to claim 3 or 4, wherein
The lower guide further includes a raised portion for covering the lower protrusion,
A recording apparatus, wherein an inclined surface is formed between the raised portion and the base surface on the upstream side in the forward direction and the downstream side in the forward direction. The recording apparatus according to any one of claims 2 to 5,
The recording apparatus further includes a flexible seal member,
The sensor is fixed to the lower guide,
The upper guide is provided so as to be swingable with respect to the lower guide,
The recording apparatus, wherein the seal member seals a boundary between the sensor and the upper guide. The recording apparatus according to any one of claims 1 to 6,
A first convex portion that supports the medium, a second convex portion that supports the medium and is provided on the downstream side in the forward direction from the first convex portion, and the first convex portion and the second convex portion. A groove provided therebetween,
The controller is
Causing the head to record the front surface of the medium while transporting the medium to the transport mechanism so that the rear end of the medium is not forward downstream of the first convex portion,
When recording the back side of the medium, the head is caused to record the rear end of the medium while the medium is transported by the transport mechanism so that the rear end of the medium is positioned on the groove. Recording device. Feed the media to the transport mechanism,
Detecting the end of the medium by a non-contact sensor before feeding the medium to the transport mechanism;
Recording the front surface of the medium while transporting the medium in the forward direction by the transport mechanism;
After recording the front surface, the medium is conveyed in a reverse direction opposite to the forward direction in order to reverse the medium by a reversing mechanism;
A recording method, wherein an edge of the medium is detected by the non-contact sensor when the medium is conveyed in a reverse direction.

Images