JP2016185614A - Recording device - Google Patents

Abstract

A recording apparatus capable of preventing ink from dripping from an end of a sheet while suppressing the number of installed sheet detecting means. A recording apparatus includes a recording head including a plurality of nozzles that discharge liquid to a medium along a medium conveyance direction, and a medium provided on a downstream side of the recording head in a conveyance path for conveying the medium. A plurality of medium detection means for detecting, the plurality of medium detection means including a first medium detection means and a second medium detection means, from among the plurality of nozzles located on the most downstream side in the medium transport direction. The path length to the first medium detecting means is X, the specified time required for the medium to travel from the first medium detecting means to the second medium detecting means is T, and a predetermined distance is set at a distance X inside from the leading edge of the medium. The second medium detecting means is provided at a position where X ≧ Y, where Y is the maximum distance that the liquid flows toward the tip on the medium when the liquid is discharged for a time T at the duty value. [Selection] Figure 7

Description

  The present invention relates to a recording apparatus including a recording head that discharges liquid onto a medium.

  In a recording apparatus including a recording head that discharges ink as an example of a liquid onto recording paper as an example of a medium, for example, an ink jet printer, a problem related to drying of the discharged ink is likely to occur. For example, in the ink jet printer described in Patent Document 1, in the configuration in which drying of the liquid on the recording surface is promoted by air blowing, in consideration of the phenomenon that ink landed by the air flows (ink flow) occurs, the ink flows. Suppressing means for suppressing air flow to the ink flow area is provided.

JP 2009-292128 A

Conventionally, in the transport path for transporting the recording paper, a paper detecting means for detecting the passage of the recording paper is provided at an appropriate position so that desired transport control is performed based on the detection information of the paper detecting means. It is configured.
For example, when the recording paper does not pass through the paper detection means even after a predetermined time has elapsed, it is determined that the paper jam has occurred, the paper conveyance operation or the recording operation is stopped, and an alert is issued to the user. Many.

When the paper jam is determined, the user opens the cover of the apparatus and removes the recording paper jammed in the conveyance path.
At this time, if the ink landed on the recording paper is not dried, when the recording paper is pulled out, the ink may flow to the end of the recording paper and eventually fall down, and the floor or the like may be soiled.

  In particular, in the so-called line head type in which the inkjet recording head has a length that covers the entire paper width and performs recording without moving in the paper width direction, the paper transport speed is extremely high and the unit Since the amount of ink ejected in time is large, the amount of ink ejected from the determination of paper jam to the stop of the recording operation is also large. Therefore, in such an ink jet printer, the above-mentioned problem becomes more remarkable.

In order to avoid the above problems, for example, it may be possible to provide more paper detection means in the paper conveyance path, but in this case, the cost increases.
Accordingly, the present invention has been made in view of such circumstances, and an object of the present invention is to provide a recording apparatus capable of preventing ink from dripping from the end of the sheet while suppressing the number of installed sheet detecting means. There is to do.

  In order to solve the above problems, a recording apparatus according to a first aspect of the present invention includes a recording head including a plurality of liquid discharge nozzles that discharge liquid onto a medium along the medium conveyance direction, and a medium conveyance A plurality of medium detection means provided on the downstream side of the recording head in the conveyance path for detecting the passage of the medium, wherein the plurality of medium detection means includes a first medium detection means and the first medium detection means. A second medium detection means positioned first downstream of the means, and the path length from the liquid discharge nozzle located at the most downstream in the medium conveyance direction to the first medium detection means among the plurality of liquid discharge nozzles is represented by X And T is a prescribed time required for the medium to travel from the first medium detecting means to the second medium detecting means, and the liquid is placed at a distance X on the inner side from the front end of the medium at a predetermined duty value for a time T. Discharged Liquid when the maximum distance that flows toward the tip was Y, and said second medium detecting means to a position to be the X ≧ Y is provided on the medium.

  According to this aspect, the first and second medium detecting means are provided toward the downstream side of the medium transport path, and the second is within a range (X ≧ Y) in which the liquid is prevented from dripping from the end of the medium. Medium detection means is provided. Therefore, by providing the second medium detection means so as to increase the value of Y while satisfying the above range, it is possible to prevent the liquid from dripping from the edge of the medium while suppressing the number of medium detection means installed. .

According to a second aspect of the present invention, in the first aspect, the predetermined duty value is a maximum duty value.
According to this aspect, since the predetermined duty value is the maximum duty value, the maximum distance Y is a distance in a state where the liquid discharge amount is the largest, and the liquid drips from the edge of the medium more reliably. Can be prevented.

  According to a third aspect of the present invention, in the first or second aspect, the maximum distance Y is set on the basis of a medium having the smallest liquid absorption amount per unit time among the mediums assumed to be used. It is characterized by that.

  According to this aspect, the maximum distance Y is set with reference to a medium that has the smallest amount of liquid absorption per unit time among the media that are assumed to be used. It becomes the distance under conditions, and it is possible to more reliably prevent the liquid from dripping from the edge of the medium.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, a rear end detection unit that detects the passage of the rear end of the medium is provided in the vicinity of the upstream side of the recording head. The medium detecting means is not arranged downstream from the front end of the medium when the end passes through the rear end detecting means.

  In a state where the rear end of the medium passes through the rear end detection means provided near the upstream of the recording head, the amount of liquid ejected thereafter is small, and the distance from the recording head to the front end of the medium is long. Therefore, in this state, when the medium is pulled out from the upstream side of the recording head, the liquid hardly drops from the front end of the medium. Accordingly, by not arranging the medium detection means downstream from the medium front end in this state, the number of medium detection means can be reduced.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, a division position of the conveyance path is set between the first medium detection unit and the second medium detection unit, and the division The unit body forming the transport path downstream from the position is configured to be removable from the main body of the recording apparatus.

  In this aspect, by setting the division position, the leading edge of the medium is easily caught between the first medium detecting means and the second medium detecting means, that is, jamming is likely to occur. However, due to the operational effects of any of the first to fourth aspects, it is possible to avoid the problem of the liquid dripping from the edge of the medium during jam processing.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, a path switching member that switches the path of the medium is provided downstream of the first medium detection unit.
In this aspect, the path switching member that switches the path of the medium is provided on the downstream side of the first medium detection means, so that the leading edge of the medium is likely to be caught in the path switching member, that is, the jam is likely to occur. However, due to the operational effects of any of the first to fourth aspects, it is possible to avoid the problem of the liquid dripping from the edge of the medium during jam processing.

  According to a seventh aspect of the present invention, there is provided a recording head comprising a plurality of liquid discharge nozzles for discharging a liquid to a medium along a medium conveying direction, and a recording path in the conveying path for conveying the medium. A plurality of medium detection means provided on the downstream side for detecting passage of the medium, wherein the plurality of medium detection means are first positioned downstream of the first medium detection means and the first medium detection means. Second medium detecting means, and third medium detecting means positioned first downstream of the second medium detecting means, and the second medium detecting means and the third medium detecting means in the transport path The path length A2 is longer than the path length A1 between the first medium detection means and the second medium detection means, and the liquid discharge nozzle located at the most downstream in the medium transport direction among the plurality of liquid discharge nozzles Second medium detection from When the path length to the stage is X, the time when the medium travels along the path length A2 is T, and the liquid is discharged at a predetermined duty value for a time T at the position of the inner distance X from the leading edge of the medium. The third medium detecting means is provided at a position where X ≧ Y, where Y is the maximum distance that the liquid flows on the medium toward the tip.

  According to this aspect, the first, second, and third medium detecting units are provided toward the downstream side of the medium conveying path, and the path length A2 between the second medium detecting unit and the third medium detecting unit is The length is set to be longer than the path length A1 between the first medium detecting means and the second medium detecting means within a range (X ≧ Y) in which the liquid is prevented from dripping from the end of the medium. Accordingly, it is possible to prevent the liquid from dripping from the edge of the medium while suppressing the number of installed medium detecting means.

1 is an external perspective view of a printer according to the present invention. FIG. 3 is a side sectional view showing a paper conveyance path of the printer according to the invention. 1 is a block diagram of a printer according to the present invention. FIG. 3 is a perspective view illustrating a state in which the opening / closing body constituting the part of the sheet conveyance path is opened with respect to the apparatus main body in the printer according to the invention. 1 is an external perspective view of a printer according to the present invention. FIG. 3 is a perspective view illustrating a state in which a unit body that constitutes a part of a sheet conveyance path is pulled out from the apparatus main body. FIG. 3 is a schematic diagram of a sheet conveyance path showing an arrangement state of a plurality of sheet detection sensors according to the first embodiment. 6 is a graph showing the relationship between ink ejection time T and ink dripping amount Y. FIG. 10 is a schematic diagram of a sheet conveyance path showing an arrangement state of a plurality of sheet detection sensors according to a second embodiment. FIG. 3 is a schematic diagram showing a state of ink dripping on paper P.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, about the same structure in each Example, the same code | symbol is attached | subjected and it demonstrates only in the first Example, The description of the structure is abbreviate | omitted in a subsequent Example.

  1 is an external perspective view of a printer according to the present invention, FIG. 2 is a side sectional view showing a paper conveyance path of the printer according to the present invention, and FIG. 3 is a block diagram of the printer according to the present invention. 4 is a perspective view of the printer according to the present invention in a state of being opened with respect to the main body of the opening / closing body that constitutes a part of the paper conveyance path, and FIG. 5 is an external perspective view of the printer according to the present invention.

  FIG. 6 is a perspective view illustrating a state in which a unit body constituting a part of the sheet conveyance path is pulled out from the apparatus main body, and FIG. 7 is a sheet conveyance illustrating the arrangement state of a plurality of sheet detection sensors according to the first embodiment. FIG. 8 is a schematic diagram of the path, FIG. 8 is a graph showing the relationship between the ink ejection time T and the ink dripping amount Y, and FIG. 9 is a paper transport showing the arrangement state of a plurality of paper detection sensors according to the second embodiment. FIG. 10 is a schematic diagram showing a state of ink dripping on the paper P. FIG.

  In the XYZ coordinate system shown in each figure, the X direction (device width direction) is the full paper width direction, the Y direction is the paper transport direction, and the Z direction is the distance (gap) between the recording head and the paper. The direction of the change, that is, the height direction of the apparatus is shown. In each figure, the −X direction is the front side of the apparatus, and the + X direction side is the back side of the apparatus.

<<< Printer overview >>>
An ink jet printer 10 (hereinafter referred to as a printer 10) as an example of a liquid ejection apparatus will be described with reference to FIG. The printer 10 is configured as a multifunction machine including an apparatus main body 12 and a scanner unit 14. The apparatus main body 12 includes a plurality of paper storage cassettes 16 for storing paper P (see FIG. 2) as “medium”. Each sheet storage cassette 16 is detachably attached from the front side (the −X axis direction side in FIG. 1) of the apparatus main body 12. In this specification, the paper P refers to paper such as plain paper, cardboard, and photographic paper as an example.

  Further, in the apparatus height direction (Z-axis direction) in the apparatus main body 12, a sheet receiving tray 20 that receives the sheet P on which recording is performed by a line head 18 described later is provided between the scanner unit 14 and the sheet storage cassette 16. Is provided. An operation unit 21 is provided on the front side of the apparatus main body 12. The operation unit 21 is provided with display means such as a liquid crystal panel. Further, by operating the operation unit 21, it is possible to input a recording operation and an image reading operation instruction to the printer 10.

<<< About the paper transport path >>>
Next, with reference to FIG. 2, the conveyance path as the “conveyance path” of the paper P as the “medium” in the printer 10 will be described. In FIG. 2, reference numerals are given only to the main components of the conveyance path of the paper P, and the reference numerals are omitted for other components, particularly a plurality of spurs.

  The printer 10 in this embodiment includes a paper transport path 22. The sheet conveyance path 22 includes a straight path 24, a switchback path 26, a reverse path 28, a face-down discharge path 30, and a feeding path 32 connected to the straight path 24 from the sheet storage cassette 16.

  In the feeding path 32, a feeding roller 34, a separation roller pair 36, and a conveyance roller pair 38 are provided in order along the conveyance direction of the paper P. The feed roller 34 is driven to rotate by a drive motor (not shown). The separation roller pair 36 separates the paper P by nipping the paper P. The transport roller pair 38 is configured as a drive roller in which one roller is rotated by a drive motor (not shown), and the other roller is configured as a driven roller.

  In the following description, it is assumed that one roller in each pair of transport rollers appearing in this specification is configured as a drive roller that is driven to rotate by a drive motor (not shown), and the other roller is configured as a driven roller. explain.

  The paper P stored in the paper storage cassette 16 is fed to the downstream side of the feeding path 32 by the feeding roller 34. The sheet P fed by the feeding roller 34 is sequentially nipped by the separation roller pair 36 and the conveying roller pair 38 and fed toward the downstream side of the feeding path 32. Further, a transport roller pair 40 is provided on the downstream side of the transport roller pair 38 in the transport direction. In this embodiment, the transport roller pair 40 includes a driving roller 40a and a driven roller 40b. In this embodiment, the driven roller 40b is configured to be able to contact and separate from the driving roller 40a (see FIG. 7).

  In the present embodiment, the feeding path 32 and the straight path 24 are connected at the position of the transport roller pair 40. That is, the feeding path 32 is set as a path from the sheet storage cassette 16 to the pair of transport rollers 40.

  The straight path 24 is configured as a path extending linearly. In the straight path 24, a pair of conveyance rollers 40, a belt conveyance unit 42, a paper pressing roller 43, a line head 18 as a “recording head”, a paper detection sensor 44 that detects the passage of the paper P, and paper A detection sensor 46 and a first flap 48 as a “path switching member” are provided. In this embodiment, the straight path 24 is set as a path from the transport roller pair 40 to the first flap 48. That is, the straight path 24 is set as a path that passes through the line head 18 and extends upstream and downstream of the line head 18.

  In this embodiment, the paper detection sensor 44 is configured as the first medium detection means in the seventh aspect, and the paper detection sensor 46 is the first medium in any one of the first to sixth aspects. The sheet detection sensor 52, which will be described later, is configured as the detection means and the second medium detection means in the seventh aspect, and the second medium detection means and the seventh aspect in any one of the first to sixth aspects. In the third medium detecting means.

  In this embodiment, when the paper P is transported to a region facing the head surface of the line head 18, the line head 18 uses ink as “liquid” from a plurality of nozzles provided on the recording surface of the paper P on the head surface. Is configured to execute recording. The line head 18 in this embodiment is a recording head provided so that nozzles that eject ink cover the entire area in the sheet width direction as an example, and recording is performed on the entire sheet width without moving in the sheet width direction. It is configured as a possible recording head.

  A belt conveying means 42 is disposed in a region facing the head surface of the line head 18. The belt conveying means 42 includes a drive shaft 42a and a driven shaft 42b, and a belt is wound around the drive shaft 42a and the driven shaft 42b. The belt conveying means 42 is driven by the rotation of the drive shaft 42a, and conveys the paper P downstream in the conveying direction. The drive shaft 42a is in contact with the paper pressing roller 43 via a belt. In this embodiment, the paper pressing roller 43 is configured to be able to contact and separate from the belt (see FIG. 7). Further, the paper pressing roller 43 suppresses the conveyed paper P from floating from the belt conveying means 42. The belt conveying means 42 supports the side opposite to the recording surface of the paper P.

  As a result, the recording surface of the paper P supported by the belt conveying means 42 faces the head surface, and recording is performed on the recording surface of the paper P by ejecting ink from the nozzles on the head surface of the line head 18. . Further, the belt conveying unit 42 defines the distance (gap) between the recording surface of the paper P and the head surface of the line head 18 by supporting the paper P from below.

  Subsequently, a sheet detection sensor 44 is disposed downstream of the line head 18 in the conveyance direction. A paper detection sensor 46 is arranged at a position away from the paper detection sensor 44 on the downstream side in the transport direction.

  A first flap 48 is located downstream of the paper detection sensor 46 in the transport direction. The first flap 48 is configured to be swingable by a drive mechanism controlled by a control unit 64 (see FIG. 3) described later. The first flap 48 has a posture (state of FIG. 2) connecting the straight path 24 and the switchback path 26 and a posture (state of reference numeral 48 'in FIG. 7) connecting the straight path 24 and the face-down discharge path 30. ) And can be switched. In the present embodiment, the drive mechanism for driving the first flap 48 is constituted by a solenoid. The posture switching operation of the first flap 48 is controlled by the control unit 64 (see FIG. 3).

  When the first flap 48 is in a posture for connecting the straight path 24 and the face-down discharge path 30 (state of reference numeral 48 ′ in FIG. 7), the sheet P is conveyed from the straight path 24 to the face-down discharge path 30 by the belt conveying means 42. Sent to.

  The face-down discharge path 30 is curved and inverted while extending upward from the straight path 24 in the apparatus height direction. A plurality of transport roller pairs 50 are provided in the face-down discharge path 30 at appropriate intervals in the transport direction. In the face-down discharge path 30, a paper detection sensor 52 is disposed on the downstream side in the transport direction with respect to the paper detection sensor 46.

  The face-down discharge path 30 is routed from the first flap 48 to the discharge port 54 positioned on the downstream side in the transport direction of the transport roller pair 50 positioned on the most downstream side in the transport direction. That is, the face-down discharge path 30 is a conveyance path that is connected to the straight path 24, and is a path that discharges the paper P that has passed through the line head 18 after being bent and inverted.

  The sheet P on which recording is performed on the recording surface by the line head 18 is sequentially nipped and conveyed by the pair of conveyance rollers 50 provided in order along the conveyance direction from the first flap 48 in the face-down discharge path 30. Then, the paper P is discharged from the discharge port 54 toward the paper receiving tray 20.

  Here, when the sheet P is conveyed along the face-down discharge path 30, the sheet P is finally conveyed with the recording surface recorded by the line head 18 facing upward, and then the recording surface is transferred to the curved portion of the face-down discharge path 30. The sheet is bent inward and conveyed, and discharged from the discharge port 54 toward the sheet receiving tray 20 with the recording surface facing downward.

<<< Conveying path of paper in double-sided recording >>>
When the first flap 48 is in a posture to connect the straight path 24 and the switchback path 26 (see FIG. 2), the paper P is sent from the straight path 24 to the switchback path 26 by the belt conveying means 42.

  The switchback path 26 and the reverse path 28 are paths through which the sheet P passes when recording on the second side after recording on the first side of the sheet P, that is, when executing double-sided recording. Similarly, when recording is performed on the second side although recording is not performed on the first side, the paper P passes through the switchback path 26 and the reverse path 28. That is, in this specification, double-sided recording means that paper P is reversed and recording is performed on the second side regardless of whether recording is performed on the first side.

  The switchback path 26 is located inside the face-down discharge path 30 that is curved and inverted upward in the apparatus height direction, and extends along the face-down discharge path 30. The switchback path 26 includes a transport roller pair 56.

  In this embodiment, the switchback path 26 is set as a path from the second flap 58 provided above the first flap 48 to the opening 60 provided at the tip of the switchback path 26. When the switchback path 26 is connected to the straight path 24 by the first flap 48 (see FIG. 2), the paper P is switched back from the area facing the line head 18 by the belt conveying means 42 via the first flap 48. It is sent to the path 26. The paper P is sent to a position where the rear end in the transport direction is nipped by the transport roller pair 56 in the switchback path 26.

  Here, the second flap 58 will be described. The second flap 58 is provided above the first flap 48 in the apparatus height direction (Z-axis direction). The second flap 58 is swung by an interlocking mechanism (not shown) in conjunction with the operation of the first flap 48. That is, the second flap 58 is controlled by the control unit 64 via the first flap 48 and the interlocking mechanism.

  The second flap 58 is configured to block the connection between the switchback path 26 and the reverse path 28 when the first flap 48 connects the straight path 24 and the switchback path 26 (see FIG. 2). On the other hand, in a state where the first flap 48 connects the straight path 24 and the face-down discharge path 30, the second flap 58 is in a posture to connect the switchback path 26 and the reverse path 28.

  When the second flap 58 takes the posture of connecting the switchback path 26 and the reversing path 28, the control unit 64 rotates the transport roller pair 56 in the direction opposite to the direction in which the paper P is sent to the switchback path 26. The paper P is sent out to the reversing path 28 with the rear end side of the paper P as the front end side. That is, the paper P is switched back.

  The reverse path 28 is set as a path from the second flap 58 to the upper side of the line head 18 to the pair of conveying rollers 40 in the straight path 24. A plurality of transport roller pairs 62 are provided in the reversing path 28 at appropriate intervals in the transport direction.

  The exit side of the reversing path 28 is configured to join the straight path 24 at a position upstream of the conveying roller pair 40 in the straight path 24. Then, the paper P is fed again into the straight path 24. In other words, the reverse path 28 is a transport path connected to the switchback path 26, and reverses the sheet P transported in the reverse direction, that is, the switched back sheet P by bypassing the upper side of the line head 18, and the straight path 24. Is set as a path to be joined by the transport roller pair 40 located at the upstream side position of the line head 18.

Then, when the paper P is transported through the reversing path 28, the first surface and the second surface are reversed, transported to an area facing the line head 18 in the straight path 24, and recording is performed on the second surface. Is done. Thereafter, the paper P is discharged to the paper receiving tray 20 through the face-down discharge path 30.
<<< About the control unit >>>
The apparatus main body 12 includes a control unit 64 (see FIG. 3) as an electric circuit composed of a plurality of electronic components. The control unit 64 includes a scanner unit 14, a line head 18, a belt conveyance unit 42, a paper detection sensor 44, a paper detection sensor 46, a first flap 48, a paper detection sensor 52, a second flap 58, and a motor driver 66 described later. Operations necessary for execution of recording and image reading of the printer 10 such as feeding, conveying, discharging, recording operation, and document reading operation of the paper P are controlled.

  The control unit 64 is electrically connected to the operation unit 21 and controls the printer 10 based on an operation input from the user operation unit 21. Further, the control unit 64 may control operations necessary for executing recording and image reading of the printer 10 such as a document reading operation in accordance with an instruction from the outside (PC or the like). Further, the control unit 64 controls ink ejection from the nozzles on the head surface of the line head 18.

  A plurality of motor drivers 66 controlled by the control unit 64 are arranged in the apparatus main body 12 and respectively control a plurality of drive motors (not shown). That is, in the present embodiment, the control unit 64 controls the driving of the feeding roller 34, the separation roller pair 36, and the transport roller pairs 38, 40, 50, 56, and 62 via the motor driver 66 and the plurality of drive motors. doing.

<<< Configuration for Jam Processing in Paper Transport Path >>>
2 and 7, an alternate long and short dash line portion denoted by reference numeral 68 indicates an opening / closing unit that can be opened and closed with respect to the apparatus main body. The opening / closing unit 68 can be in a closed state with respect to the apparatus main body 12 shown in FIG. 1 and in an open state with respect to the apparatus main body 12 shown in FIG. The opening / closing unit 68 has a rotation fulcrum (not shown) at the end on the + X axis direction side. The opening / closing unit 68 is configured to be rotatable with respect to the apparatus main body 12 around the rotation fulcrum (see FIGS. 1 and 4).

  As shown in FIG. 4, when the opening / closing unit 68 is opened with respect to the apparatus main body 12, a part of the feeding path 32 and a part of the reversing path 28 are exposed. Further, when the opening / closing unit 68 is opened with respect to the apparatus main body 12, the driven roller 40b is retracted from the contact position with the driving roller 40a in the transport roller pair 40, and the nip state of the transport roller pair 40 is eliminated ( (See reference numeral 40b 'in FIG. 7). Further, the paper pressing roller 43 is also separated from the belt conveying means 42 when the opening / closing unit 68 is opened with respect to the apparatus main body 12, and the nip state between the paper pressing roller 43 and the belt conveying means 42 is eliminated ( (See reference numeral 43 'in FIG. 7).

  Further, in this embodiment, when the opening / closing unit 68 is opened with respect to the apparatus main body 12, the line head 18 moves from the state where the distance to the belt of the belt conveying means 42 is defined to the upper side in the apparatus height direction. Retreat (see reference numeral 18 'in FIG. 7). In this state, the user exposes a part of the feeding path 32 and a part of the reversing path 28 and moves the driven roller 40b, the paper pressing roller 43, and the line head 18 to the retracted positions (reference numerals 40b 'and 43' in FIG. 7). And 18 '), access to the jammed paper P is facilitated. Thus, when the paper P is jammed at a position corresponding to the line head 18, the user can easily perform the paper jam processing (paper jam processing) of the paper P.

  2 and 7 again, the two-dot chain line portion denoted by reference numeral 70 in FIGS. 2 and 7 is in the first state (FIG. 5) and a second state (see FIG. 6) in which the sheet conveyance path 22 is opened.

The unit body 70 is curved in the straight path 24 from the downstream side of the belt conveying means 42 to the first flap 48 and the second flap 58, and in the switchback path 26 from the second flap 58 through the conveying roller pair 56 to reverse the curve. Includes the route to the middle of the part. Furthermore, the unit body 70 passes through the pair of transport rollers 50, 50, 50, 50 from the first flap 48 in the face-down discharge path 30 and is fifth from the pair of transport rollers 50 provided from the first flap 48. A route up to the middle of the route toward the provided transport roller pair 50 is included.

  As shown in FIGS. 5 and 6, the unit body 70 is configured to be movable with respect to the apparatus main body 12 along the paper transport direction (the Y-axis direction in FIGS. 5 and 6). In this embodiment, a pair of rail members 72 provided in the apparatus main body 12 are configured to be able to be taken in and out of the apparatus main body 12.

  In the present embodiment, the first transport roller pair 50 provided downstream from the first flap 48 in the transport direction of the paper P is in a direction in which the driven roller 50b contacts and separates from the drive roller 50a. It is configured to be movable. In this embodiment, when the unit body 70 is in the second state, the driven roller 50b retreats from the position where it contacts the driving roller 50a, and the nip state between the driving roller 50a and the driven roller 50b is eliminated (FIG. 7). Reference numeral 50b '). When the unit body 70 is in the second state, the line head 18 retreats upward in the apparatus height direction from the state where the distance of the belt conveying means 42 from the belt is defined (see reference numeral 18 'in FIG. 7). ).

  As shown in FIG. 6, when the unit body 70 is pulled out from the apparatus main body 12 (second state), a part of the straight path 24, a part of the switchback path 26, and the face-down discharge path 30. Is exposed toward the outside of the apparatus main body 12. In particular, in this embodiment, the division positions of the unit body 70 and the apparatus main body 12 are set in the middle of the curved portion of the switchback path 26 and the curved portion of the face-down discharge path 30. As a result, when the paper P is jammed in the curved portion of the switchback path 26 and the curved portion of the face-down discharge path 30, the unit body 70 is brought into the second state (see FIG. 6), thereby switching back. It is possible to easily perform a paper jam handling operation in the curved portion of the path 26 and the curved portion of the face-down discharge path 30.

  Although the unit body 70 is in the second state (see FIG. 6), it is possible to access the vicinity of the line head 18, but a paper jam occurs when the line head 18 and the paper P face each other. In this case, when the paper P jammed in the second state is to be removed, there is a possibility that the user touches the portion where the ink has already been ejected and gets his hands dirty. Therefore, in this embodiment, when a paper jam occurs in a state where the line head 18 and the paper P face each other, it is assumed that the paper jam processing is performed from the feeding path 32 side.

■■■ First Example ■■■■
With reference to FIGS. 7, 8, and 10, the sheet detection sensors 74 as a plurality of “medium detection units” arranged in the sheet conveyance path 22 will be described. In this embodiment, the paper detection sensor 74 includes a paper detection sensor 44, a paper detection sensor 46, and a paper detection sensor 52. In FIG. 7, the illustration of the paper conveyance path 22 is omitted except for a part for explanation, and a part of the paper conveyance path 22 is drawn linearly for the sake of simplicity.

  Referring to FIG. 7, the paper P is transported downstream in the transport direction at the transport speed V. Reference numeral X0 represents the position of the ink discharge nozzle located at the most downstream side in the paper transport direction in the line head 18 in the paper transport direction. In the present embodiment, the paper detection sensor 44 is disposed at a distance X1 away from the ink discharge nozzle located on the most downstream side of the line head 18 in the straight path 24 on the downstream side in the transport direction.

  A paper detection sensor 46 is disposed downstream of the paper detection sensor 44 in the transport direction with a path length A1 therebetween. Further, a paper detection sensor 52 is disposed on the downstream side in the transport direction of the paper detection sensor 46 with a path length A2 therebetween. In this embodiment, the paper detection sensor 46 is provided at a position corresponding to the boundary between the apparatus main body 12 and the unit body 70 in the paper transport path 22. Thus, by arranging the paper detection sensor 46 near the boundary between the apparatus main body 12 and the unit body 70, it is possible to more reliably detect the paper jam of the paper P that is likely to occur near the boundary between the apparatus main body 12 and the unit body 70. can do.

Here, the ink dripping amount Y (mm) will be described with reference to FIG.
When a paper jam occurs when the line head 18 and the paper P face each other, if print data remains, ink is continuously ejected from the line head 18 while the paper P is stopped. That is, a large amount of ink may be ejected at the same position on the paper P. When such a paper P is pulled out, the ink flows on the recording surface and eventually reaches the front end of the paper and drips down. There is a risk of fouling.

FIG. 10 shows an example of the situation of such ink dripping, and the symbol Ps indicates the front end of the paper (the downstream end in the transport direction). In FIG. 10, black portions indicate ink that has been ejected onto the paper P and has flowed.
When a paper jam occurs, the opening / closing unit 68 is opened with respect to the apparatus main body 12, and the paper P that has caused a paper jam from the paper transport path 22 is removed in the -Y-axis direction in FIG. Ink that is not absorbed by the paper P flows to the front end side of the paper P. Here, the ink dripping amount Y (mm) indicates the distance at which the ink flows from the position X0 of the ink discharge nozzle located at the most downstream side in the paper conveyance direction in the line head 18 to the front end Ps side of the paper P, that is, the dripping distance. Yes. Further, as shown in FIG. 10, the maximum value of the ink dripping amount Y (mm) is the distance from the ink discharge nozzle position X0 to the leading end Ps of the paper P.

  In particular, in this embodiment, the line head 18 is of a type that extends in the paper width direction, has ink discharge nozzles arranged in the paper width direction, and discharges ink without moving in the paper width direction. For this reason, the amount of ink discharged per unit time is larger, and the above-mentioned ink dripping can occur more remarkably.

  On the other hand, if the control unit 64 determines that a paper jam has occurred, it can stop the ink ejection. Judgment of paper jam is based on the paper conveyance speed and the distance between each sensor, and when each sensor does not detect passage of the paper front end Ps even after the time that the paper front end Ps should reach, it is determined that the paper jam has occurred. be able to. For example, in the example of FIG. 7, even if the time (= distance A2 / conveying speed V) that originally reaches the paper detection sensor 52 elapses after the paper leading edge Ps passes through the paper detection sensor 46, the paper detection sensor 52 If the passage of the leading edge Ps is not detected, it can be determined that a paper jam has occurred.

However, there is a time lag between the actual occurrence of a paper jam and the determination of the paper jam. For example, in the above example, this time lag becomes maximum (worst) when a paper jam occurs immediately after paper detection sensor 46 detects the passage of paper front end Ps (substantially simultaneously). That is, the ink is continuously ejected at one place of the paper P during the maximum (worst) time.
Therefore, from the viewpoint of suppressing the ink dripping, it is preferable to set the distance between the sensors short. However, if the distance between the sensors is shortened, the number of sensors arranged increases and the cost increases.
The purpose of this aspect is to prevent ink from dripping from the edge of the paper while minimizing the number of sensors.

  Further details will be described below. FIG. 8 shows the relationship between the ink ejection time T (ms) and the ink dripping amount Y (mm) at a predetermined duty value. The relationship between the ink ejection time T (ms) and the ink dripping amount Y (mm) is represented by the equation Y = R × T. That is, the ink dripping amount Y (mm) and the ink ejection time T (ms) are in a proportional relationship.

  In the above equation, R represents an ink dripping coefficient. The ink dripping coefficient R changes according to the paper type of the paper P and the type of ink. Further, the predetermined duty value in FIG. 8 is set to the maximum duty value in this embodiment. In this embodiment, the paper P is based on a medium having the smallest ink absorption amount per unit time.

  Referring to FIG. 7, the paper P is transported downstream in the transport direction at the transport speed V. Here, assuming that the paper P has jammed immediately after the paper detection sensor 44 detects the leading edge Ps of the paper P, the allowable amount of ink dripping on the paper P is from the ink discharge nozzle position X0 to the paper detection sensor 44. Distance X1.

  In FIG. 8, the ink ejection time corresponding to the ink dripping amount Y1 corresponding to the distance X1 is T1 (ms). In other words, if ink ejection is stopped within the ink ejection time T1 after the paper detection sensor 44 detects the front edge Ps of the paper P, the ink dripping amount Y1 does not exceed the distance X1 and the paper P starts from the front edge Ps. Ink can be prevented from dripping.

  In other words, whether or not the paper detection sensor 46 detects the front end Ps of the paper P after the paper detection sensor 44 detects the front end Ps of the paper P until the ink discharge time T1 elapses. If it is configured to detect the paper jam, the ink does not drip from the paper leading edge Ps even in the worst case. In this way, the ink discharge time T1 is from the time when the upstream paper detection sensor 44 detects the leading edge Ps of the paper P in the paper conveyance path 22 to the time when the downstream paper detection sensor 46 detects the leading edge Ps of the paper P. It can be set as the paper jam detection timer time.

The path length A1 between the paper detection sensor 44 and the paper detection sensor 46 can be expressed by the product of the paper jam detection timer (ink ejection time) T1 and the conveyance speed V of the paper P. That is, the path length A1 = T1 × V. Accordingly, the paper detection sensor 46 may be disposed at a position away from the paper detection sensor 44 by a distance [T1 × V] on the downstream side in the transport direction.
As described above, the sheet detection sensor 46 is disposed at a position separated by a distance X2 as a “path length X” on the downstream side of the sheet conveyance path from the position X0 of the ink discharge nozzle located at the most downstream in the sheet conveyance direction in the line head 18. To do.

Thereafter, the distance between the sensors can be set in the same manner, but as is clear from the above description, the distance from the position X0 to the leading edge Ps of the sheet increases as the conveyance of the sheet proceeds, that is, a paper jam. The detection timer time increases. Accordingly, the distance between the sensors can be increased toward the downstream side in the transport direction.
Hereinafter, specific examples will be described.

  Next, if the paper P causes a paper jam immediately after the paper detection sensor 46 detects the leading edge Ps of the paper P, the allowable amount of ink dripping on the paper P is from the ink discharge nozzle position X0 to the paper detection sensor 46. Distance X2.

  In FIG. 8, the ink ejection time corresponding to the ink dripping amount Y2 corresponding to the distance X2 is T2 (ms). Since the distance X2 is longer than the distance X1 already described, the ink dripping amount Y2 corresponding to the distance X2 is naturally longer than Y1. If the paper detection sensor 46 detects the leading edge Ps of the paper P within the ink discharge time T2, the ink dripping amount Y2 does not exceed the distance X2, so that the ink drops from the leading edge Ps of the paper P. Can be prevented.

  In other words, whether the paper detection sensor 52 detects the front end Ps of the paper P after the ink detection time T2 elapses after the paper detection sensor 46 detects the front end Ps of the paper P. If it is configured to detect the paper jam, the ink does not drip from the paper leading edge Ps even in the worst case. In this way, the ink discharge time T2 is from the time when the upstream paper detection sensor 46 detects the leading edge Ps of the paper P in the paper conveyance path 22 to the time when the downstream paper detection sensor 52 detects the leading edge Ps of the paper P. It can be set as the paper jam detection timer time.

The path length A2 between the paper detection sensor 46 and the paper detection sensor 52 can be expressed by the product of the paper jam detection timer (ink ejection time) T2 and the conveyance speed V of the paper P. That is, the path length A2 = T2 × V. Accordingly, the paper detection sensor 52 may be disposed at a position away from the paper detection sensor 46 by a distance [T2 × V] on the downstream side in the transport direction.
The paper jam detection timer T2 is “time T when the paper P travels the path length A2.”
As described above, the sheet detection sensor 52 is disposed at a distance X3 away from the position X0 of the ink discharge nozzle located at the most downstream side in the sheet conveyance direction in the line head 18 on the downstream side of the sheet conveyance path.

  In summary, the distance from the ink discharge nozzle position X0 to the leading end Ps of the paper P increases as the paper P is transported downstream in the transport direction along the paper transport path 22. The allowable ink dripping amount Y increases. As a result, the ink discharge time T, that is, the paper jam detection timer also becomes longer, so that the plurality of paper detection sensors 74 arranged along the paper conveyance path 22 are arranged between the paper detection sensors 74 as they go downstream in the paper conveyance direction. The path length can be increased.

  Here, the paper jam detection time of the paper detection sensor 46 is T1, the paper jam detection time of the paper detection sensor 52 is T2, the distance from the ink discharge nozzle position X0 to the paper detection sensor 44 is X1, and the ink discharge nozzle The distance from the position X0 to the paper detection sensor 46 is X2, and the distance from the ink discharge nozzle position X0 to the paper detection sensor 52 is X3.

The relationship between the distance from the paper jam detection time and the ink position of the discharge nozzle X0 until the paper detection sensor _{74, T n = (X n +} 1 -X n) / V is satisfied relationship. Here, the relationship in which the distance to the leading edge Ps of the paper P ≧ the amount of ink dripping is X _n ≧ R × T _{n + 1} .

Therefore, the distance _{Xn + 1} from the ink discharge nozzle position X0 to the paper detection sensor 74 is expressed by _{Xn + 1} ≦ (V / R + 1) × _Xn . That is, by arranging a plurality of paper detection sensors 74 in the paper transport path 22 so as to satisfy the expression on the left, the number of paper detection sensors 74 on the paper transport path 22 can be suppressed.

  In the present embodiment, a first flap 48 for switching between the face-down discharge path 30 and the switchback path 26 is disposed between the sheet detection sensor 46 and the sheet detection sensor 52 in the sheet conveyance path 22. In addition, the region surrounded by the two-dot chain line denoted by reference numeral 70 in FIG. 7 indicates the region of the unit body 70 in the straight path 24, and the area surrounded by the one-dot chain line denoted by reference numeral 68 is the straight path 24. The area of the opening / closing unit 68 in FIG.

  That is, when the opening / closing unit 68 is opened with respect to the apparatus main body 12 in FIG. 7, the straight path 24 is divided immediately before the pair of transport rollers 40, so that access to the pair of transport rollers 40 becomes easy. In FIG. 7, when the unit body 70 is in the second state with respect to the apparatus main body 12, the straight path 24 is divided between the paper detection sensor 44 and the paper detection sensor 46. Access to around 18 is possible.

<<< Relationship between Ink Drip Amount and Paper Conveying Speed >>>
In the above description, the predetermined duty value is set to the maximum duty value for the ink dripping amount Y (mm), and the conveyance speed of the paper P is described as V. However, the ink dripping amount Y (mm) is the conveyance speed of the paper P. Also affected by changes. Hereinafter, the ink dripping amount Y (mm) when the conveyance speed of the paper P is changed will be described.

  Here, as an example, the printer 10 in this embodiment has a normal recording mode in which the line head 18 performs recording on the paper P with a predetermined recording quality, and a recording quality higher than that in the normal recording mode for the paper P. And a high-definition recording mode for executing recording with fine recording quality. The transport speed of the paper P in the normal recording mode is set as V1, and the transport speed of the paper P in the high-definition recording mode is set as V2. The conveyance speed V1 and the conveyance speed V2 have a relationship of V1> V2. Hereinafter, this will be described with reference to Table 1.

  Since the paper P is transported at the transport speed V1 in the normal recording mode, the specified time taken to move the path length A2 from the paper detection sensor 46 to the paper detection sensor 52 is [A2 / V1]. On the other hand, in the high-definition recording mode, the specified time taken to move the path length A2 is [A2 / V2]. Here, since the conveyance speed V1 and the conveyance speed V2 have a relationship of V1> V2, the specified time [A2 / V1] and the specified time [A2 / V2] are [A2 / V1] <[A2 / V2]. It becomes the relationship. That is, the specified time required for the paper P to move along the path length A2 is longer in the high-definition recording mode than in the normal recording mode.

  Then, when the ink dripping amount Y in each recording mode is obtained based on this result, the ink dripping amount in the normal recording mode is [R × A2 / V1] from the relational expression [Y = R × T]. The ink dripping amount in the fine recording mode is [R × A2 / V2]. Here, since the specified time [A2 / V1] and the specified time [A2 / V2] are in a relationship of [A2 / V1] <[A2 / V2], the ink dripping amount [R × A2 / V1] and the ink The sag amount [R × A2 / V2] has a relationship of [R × A2 / V1] <[R × A2 / V2].

  That is, the ink dripping amount Y is higher in the high-definition recording mode than in the normal recording mode. In other words, the ink dripping amount Y is greater at the transport speed V2 than at the transport speed V1. That is, the ink dripping amount Y increases as the conveyance speed decreases.

Therefore, in this embodiment, the ink dripping amount Y is obtained based on the slowest conveyance speed of the paper P, and the relationship with [X _{n + 1} ≦ (V / R + 1) × X _n ] based on the obtained ink dripping amount Y. By disposing a plurality of paper detection sensors 74 so as to satisfy the condition, ink dripping from the paper edge of the paper P can be more reliably prevented.

  Further, the printer 10 according to the present embodiment passes through each of the feeding path 32, the straight path 24, and the face-down discharge path 30 in this order, and performs single-sided recording that records only one side of the paper P, the feeding path 32, and the straight path. It is possible to execute double-sided recording in which recording is performed on both sides of the paper P through each path in the order of 24, switchback path 26, reverse path 28, straight path 24, and face-down discharge path 30.

  Here, in the printer 10, when performing double-sided recording on the paper P, if the conveyance roller member comes into contact with the surface on which recording has been performed in a state where the ink is not dry as the paper P is reversed, the recording surface is soiled. There is a risk of causing it. Accordingly, when performing double-sided recording, it is desirable to invert the paper P after the ink on the surface on which the recording of the paper P has been performed contacts the transport roller member and dry to such an extent that the recording surface is not soiled.

  In this embodiment, if the conveyance speed of the paper P in single-sided recording is V3, the conveyance speed of the paper P in double-sided recording can be set to a speed V4 that is slower than the speed V3. That is, the relationship of V3> V4 can be established. Hereinafter, this will be described with reference to Table 2.

  The specified time required for the sheet P to move along the path length A2 in single-sided recording is [A2 / V3]. On the other hand, the specified time for double-sided recording is [A2 / V4]. Since single-sided recording and double-sided recording have a relationship of V3> V4, the relationship of the specified time is [A2 / V3] <[A2 / V4]. Based on this relationship, the relationship between the ink dripping amount [R × A2 / V3] in single-sided recording and the ink dripping amount [R × A2 / V4] in double-sided recording is [R × A2 / V3] <[R × A2 / V4].

Therefore, the ink dripping amount Y in double-sided recording is larger than the ink dripping amount Y in single-sided recording. However, also in this embodiment, the ink dripping amount Y is obtained based on the conveyance speed V4 of the paper P, and the relationship of [X _{n + 1} ≦ (V / R + 1) × X _n ] is obtained based on the obtained ink dripping amount Y. By disposing the plurality of paper detection sensors 74 so as to satisfy the condition, ink dripping from the paper edge of the paper P can be prevented more reliably.

  Further, in this embodiment, the conveyance speed V4 of the paper P in the double-sided recording is slower than the conveyance speed V3 of the paper P in the single-sided recording, and therefore the straight path via the switchback path 26 and the reverse path 28 after the single-sided recording of the paper P. 24 and by extension, the time required for the sheet P to be reversed and returned to the area facing the line head 18 can be lengthened. As a result, it is possible to lengthen the ink drying time on the surface already recorded on the paper P, so that it is possible to suppress a decrease in the recording quality of the paper P.

  In this embodiment, a paper detection sensor 46 and a paper detection sensor 52 are provided toward the downstream side of the paper conveyance path 22, and the paper is within a range (X ≧ Y) that prevents ink from dripping from the paper edge. A detection sensor 52 is provided. Therefore, by providing the paper detection sensor 52 so as to increase the value of Y while satisfying the above range, it is possible to prevent the ink from dripping from the edge of the paper while suppressing the number of paper detection sensors 74 installed. .

  In this embodiment, since the predetermined duty value is set to the maximum duty value, the maximum distance Y is the distance in the state where the ink discharge amount is the largest, and the ink dripping from the edge of the paper is more reliably performed. Can be prevented.

  In this embodiment, the maximum distance Y is set on the basis of the paper P that has the smallest ink absorption amount per unit time among the paper P that is supposed to be used. Thus, it is possible to more reliably prevent ink from dripping from the edge of the sheet.

  Further, in this embodiment, the setting of the division position of the unit body 70 makes it easy for the leading edge of the paper to be caught between the paper detection sensor 46 and the paper detection sensor 52, that is, to easily cause a jam. However, in this embodiment, the path length A2 between the paper detection sensor 46 and the paper detection sensor 52 is set so as to be in a range (X ≧ Y) that prevents ink from dripping from the edge of the paper. The problem of ink dripping from the edge of the paper P during processing can be avoided.

  In the present embodiment, the first flap 48 for switching the paper path is provided on the downstream side of the paper detection sensor 46, so that the leading edge of the paper P is likely to be caught in the first flap 48, that is, a jam is likely to occur. However, in this embodiment, the path length A2 between the paper detection sensor 46 and the paper detection sensor 52 is set so as to be in a range (X ≧ Y) that prevents ink from dripping from the edge of the paper P. Further, it is possible to avoid the problem of ink dripping from the edge of the paper P during the jam processing.

  In this embodiment, a paper detection sensor 44, a paper detection sensor 46, and a paper detection sensor 52 are provided toward the downstream side of the paper transport path 22, and the path length A 2 between the paper detection sensor 46 and the paper detection sensor 52 is The length is set to be longer than the path length A1 between the paper detection sensor 44 and the paper detection sensor 46 in a range (X ≧ Y) for preventing ink from dripping from the edge of the paper. Therefore, it is possible to prevent the ink from dripping from the edge of the paper while suppressing the number of paper detection sensors 74 installed.

<<< Modification of the first embodiment >>>
(1) In the present embodiment, the unit body 70 is configured to be movable along the paper conveyance direction by the rail member 72 with respect to the apparatus main body 12, but instead of this structure, the unit body 70 is moved from the apparatus main body 12. It is good also as a structure to remove.
(2) In this embodiment, the paper detection sensor 74 includes the paper detection sensor 44, the paper detection sensor 46, and the paper detection sensor 52, but a plurality of paper detection sensors 74 are further provided along the paper transport path 22. May be.

(3) The relationship between the ink ejection time T (ms) and the ink dripping amount Y (mm) shown in FIG. 8, and the ink dripping coefficient R obtained from the relationship can be obtained under various conditions.
For example, in the present embodiment, the paper with the smallest ink absorption amount per unit time is used, and the ink dripping coefficient R when ink is ejected at the maximum duty value is obtained from the test result, that is, the most safety is considered. The ink dripping coefficient R is obtained under the above-mentioned conditions. For example, an average value may be used for the duty value, and the most frequently used paper (for example, plain paper) is used for the test. Also good.
In addition, when measuring the ink dripping amount Y (mm), it is the most safe condition that the posture of the paper is a right angle (ink droops vertically downward), but based on the actual condition at the time of paper jam processing, The ink dripping amount Y (mm) may be measured with a predetermined inclination posture.
Furthermore, when measuring the ink dripping amount Y (mm), it is the most safe condition to wait until the ink is completely dried. However, based on the actual condition at the time of paper jam processing, The ink dripping amount Y (mm) after a predetermined time may be measured without waiting for drying.
(4) In this embodiment, when the line head 18 is in a state in which the opening / closing unit 68 is open with respect to the apparatus main body 12 or when the unit body 70 is in the second state with respect to the apparatus main body 12, The line head 18 is in a state in which the opening / closing unit 68 is open with respect to the apparatus main body 12 or the unit body 70 is in the second state with respect to the apparatus main body 12 instead of this configuration. In this case, a configuration may be adopted in which a predetermined distance (gap) is maintained from the belt conveying means 42.

■■■ Second Example ■■■■
A second embodiment will be described with reference to FIG. The second embodiment is different from the first embodiment in that a paper rear end detection sensor 76 as a “rear end detection unit” is provided in the paper transport path 22.

  In the present embodiment, a paper trailing edge detection sensor 76 is disposed at a corresponding position on the upstream side of the line head 18 in the straight path 24, that is, in the vicinity thereof. The sheet trailing edge detection sensor 76 detects the trailing edge of the sheet P in the vicinity of the upstream side of the line head 18 when the sheet P is conveyed along the sheet conveying path 22.

  In the present embodiment, the paper detection sensor 74 is arranged on the downstream side in the transport direction from the leading edge of the paper P when the trailing edge of the paper P of a predetermined size is detected by the paper trailing edge detection sensor 76 in the paper transport path 22. It has not been.

  In this embodiment, when the sheet trailing edge detection sensor 76 detects the trailing edge of the sheet P, the distance from the trailing edge of the sheet P to the head surface of the line head 18 is short, and the line head 18 at the time of the detection The ink discharge amount in the recording operation from the ink discharge position to the rear end of the paper P is small.

  In this state, when the paper P is pulled out from the upstream side in the transport direction of the line head 18, the ink hardly drops from the front end Ps of the paper P. It is not necessary to dispose the paper detection sensor 74 for detecting a paper jam from a position exceeding the paper length L in the transport direction of the paper P on the downstream side in the transport direction from the placement position.

  That is, in this embodiment, in a state where the rear end of the paper P has passed through the paper rear end detection sensor 76 provided in the vicinity of the upstream of the line head 18, it is discharged from the line head 18 toward the paper P thereafter. The amount of ink is small, and the distance from the line head 18 to the leading edge Ps of the paper P is long. Therefore, in this state, when the paper P is pulled out from the upstream side of the line head 18, the ink hardly drips from the front end Ps of the paper P. Therefore, by not arranging the sheet detection sensor 74 downstream from the leading end Ps of the sheet P in this state, the number of sheet detection sensors 74 can be reduced.

  In summary, the printer 10 includes a line head 18 that includes a plurality of ink ejection nozzles that eject ink onto the paper P along the transport direction of the paper P, and a line head in the paper transport path 22 that transports the paper P. 18 and a plurality of paper detection sensors 74 for detecting the passage of the paper P, which are provided downstream of the paper 18. The plurality of paper detection sensors 74 include a paper detection sensor 44 and a paper detection sensor 46 that is first positioned downstream of the paper detection sensor 44. The path length from the ink discharge nozzle located at the most downstream in the transport direction of the paper P to the paper detection sensor 46 among the plurality of ink discharge nozzles is X2, and it takes when the paper P advances from the paper detection sensor 46 to the paper detection sensor 52. The maximum distance that the ink flows on the paper P toward the front edge of the paper P when the ink is ejected at a predetermined duty value at a position of the inner distance X2 from the front edge of the paper P for a time T2 when the specified time is T2. The sheet detection sensor 52 is provided at a position where X2 ≧ Y2, where Y2 is Y2.

  In the printer 10, the predetermined duty value is set to the maximum duty value. Further, the maximum distance Y is set with reference to a medium having the smallest liquid absorption amount per unit time among the sheets P assumed to be used.

  The printer 10 includes a paper trailing edge detection sensor 76 that detects passage of the trailing edge of the paper P in the vicinity of the upstream side of the line head 18. The paper detection sensor 74 is not arranged downstream from the front edge of the paper when the rear edge of the paper P of a predetermined size passes the paper rear edge detection sensor.

  In the printer 10, the division position of the unit body 70 in the paper transport path 22 is set between the paper detection sensor 46 and the paper detection sensor 52. The unit body 70 that forms the downstream sheet conveyance path from the division position is configured to be removable from the apparatus main body 12 of the printer 10. A first flap 48 for switching the path of the paper P is provided on the downstream side of the paper detection sensor 46.

  In addition, the printer 10 includes a line head 18 including a plurality of ink ejection nozzles that eject ink onto the paper P along the transport direction of the paper P, and a downstream of the line head 18 in the paper transport path 22 that transports the paper P. And a plurality of paper detection sensors 74 for detecting the passage of the paper P. The plurality of paper detection sensors 74 include a paper detection sensor 44, a paper detection sensor 46 that is first positioned downstream of the paper detection sensor 44, and a paper detection sensor 52 that is first positioned downstream of the paper detection sensor 46. Contains. A path length A 2 between the paper detection sensor 46 and the paper detection sensor 52 in the paper transport path 22 is longer than a path length A 1 between the paper detection sensor 44 and the paper detection sensor 46. Of the plurality of ink ejection nozzles, the path length from the ink ejection nozzle located on the most downstream side in the transport direction of the paper P to the paper detection sensor 46 is X2, and the time when the paper P travels the path length A2 is T2. When the maximum distance that the ink flows toward the front end of the paper P on the paper P when the ink is ejected to the position of the inner distance X2 from the front end of the paper at the predetermined duty value for the time T2, X2 A paper detection sensor 52 is provided at a position where ≧ Y2.

  In the above-described embodiment, the line head 18 as a recording head is a type that discharges liquid in a fixed state without moving. However, the present invention is not limited to this, and the nozzle of the recording head moves while the recording head moves in a predetermined direction. The present invention can also be applied to a type in which liquid is discharged from.

In this embodiment, the paper detection sensor 74 and the paper trailing edge detection sensor 76 according to the present invention are applied to an ink jet printer as an example of a recording apparatus. However, the present invention can also be applied to other liquid ejecting apparatuses in general.
Here, the liquid ejecting apparatus uses an ink jet recording head, and is not limited to a recording apparatus such as a printer, a copier, and a facsimile machine that discharges ink from the recording head to perform recording on a recording medium. And a device for ejecting a liquid corresponding to the application from a liquid ejecting head corresponding to the ink jet recording head to an ejected medium corresponding to the recording medium, and attaching the liquid to the ejected medium.

  In addition to the recording head, as a liquid ejecting head, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, and an electrode material (conductive paste) used for forming an electrode such as an organic EL display or a surface emitting display (FED) Examples thereof include an ejection head, a bioorganic matter ejection head used for biochip production, and a sample ejection head as a precision pipette.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

10 Printer, 12 Main body, 14 Scanner unit,
16 paper storage cassette, 18 line head, 20 paper receiving tray, 21 operation unit,
22 paper transport path, 24 straight path, 26 switchback path,
28 Reverse path, 30 Face down discharge path, 32 Feed path, 34 Feed roller,
36 Separating roller pair, 38, 40, 50, 56, 62 Conveying roller pair,
40a driving roller, 40b driven roller, 42 belt conveying means, 42a driving shaft, 42b driven shaft, 43 paper pressing roller, 44, 46, 52, 74 paper detection sensor,
48 1st flap, 50a Drive roller, 50b Follower roller, 54 Discharge port,
58 second flap, 60 opening, 64 control unit, 66 motor driver,
68 opening / closing unit, 70 unit body, 72 rail member,
76 Paper trailing edge detection sensor, A1, A2 Path length, P paper, Ps Paper P,
R Ink dripping coefficient, T, T1, T2 Ink ejection time,
V, V1, V2, V3, V4 Transport speed, X, X1, X2, X3 distance,
Y, Y1, Y2 Ink dripping amount

Claims (7)

A recording head comprising a plurality of liquid ejection nozzles for ejecting liquid to the medium along the conveyance direction of the medium;
A plurality of medium detection means provided on the downstream side of the recording head in the conveyance path for conveying the medium, for detecting passage of the medium;
The plurality of medium detection means includes a first medium detection means and a second medium detection means that is first positioned downstream of the first medium detection means,
A path length from the liquid discharge nozzle located at the most downstream side in the medium transport direction to the first medium detection means among the plurality of liquid discharge nozzles is X, and the medium is from the first medium detection means to the second medium detection means. T is a predetermined time required to travel to the maximum, and when the liquid is discharged at a predetermined duty value at a position of an inner distance X from the front end of the medium for a time T, the maximum liquid flows on the medium toward the front end. When the distance is Y, the second medium detection means is provided at a position where X ≧ Y.
A recording apparatus. The recording apparatus according to claim 1, wherein the predetermined duty value is a maximum duty value.
A recording apparatus. 3. The recording apparatus according to claim 1, wherein the maximum distance Y is set based on a medium having the smallest liquid absorption amount per unit time among media assumed to be used.
A recording apparatus. The recording apparatus according to any one of claims 1 to 3, further comprising a rear end detection unit that detects passage of a rear end of the medium in the vicinity of the upstream of the recording head.
The medium detection means is not arranged downstream from the front end of the medium when the rear end of a medium of a predetermined size passes through the rear end detection means.
A recording apparatus. In the recording apparatus according to any one of claims 1 to 4, a division position of the conveyance path is set between the first medium detection unit and the second medium detection unit,
The unit body forming the transport path downstream from the division position is configured to be removable from the main body of the recording apparatus.
A recording apparatus. The recording apparatus according to any one of claims 1 to 5, further comprising a path switching member that switches a path of the medium on a downstream side of the first medium detection unit.
A recording apparatus. A recording head comprising a plurality of liquid ejection nozzles for ejecting liquid to the medium along the conveyance direction of the medium;
A plurality of medium detection means provided on the downstream side of the recording head in the conveyance path for conveying the medium, for detecting passage of the medium;
The plurality of medium detection means include a first medium detection means, a second medium detection means first positioned downstream of the first medium detection means, and a third position first positioned downstream of the second medium detection means. Medium detection means,
A path length A2 between the second medium detection means and the third medium detection means in the transport path is longer than a path length A1 between the first medium detection means and the second medium detection means,
The path length from the liquid discharge nozzle located at the most downstream side in the medium transport direction to the second medium detection unit among the plurality of liquid discharge nozzles is X, and the time when the medium travels the path length A2 is T. X ≧ Y, where Y is the maximum distance that the liquid flows on the medium toward the front end when the liquid is discharged at a predetermined duty value at the position of the inner distance X from the front end of the medium for a time T. The third medium detection means is provided at a position where
A recording apparatus.

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