JP2011025546A - Image recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means using a pair of optical sensors for detecting a remaining sheet amount and a sheet width on a sheet placing part. <P>SOLUTION: The light emitting element 67 is disposed on a paper feeding means which moves in a first direction 121 in accordance with the thickness of the sheets placed in the paper feed tray 20, and light emitted from the light emitting element 67 and transmitted toward a carriage 38 through a gap between light shielding lines is received by the light receiving element 68 mounted on the carriage 38, then, the second position P2 of the carriage is detected by a position detecting means. The remaining sheet amount in the paper feed tray 20 is detected based on the second position P2. Besides, the light emitted from the light emitting element 67 and transmitted through a light transmission part 52 is received by the light receiving element 68 mounted on the carriage 38, and the fourth position P4 of the carriage is detected by the position detecting means. The position of the end portion of the sheet is determined based on the fourth position P4 and a third position P3. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image recording apparatus that can detect the presence / absence of a sheet in a sheet placement section and the width of a sheet on a platen using a set of optical sensors.

  Conventional image recording apparatuses are known which can detect the remaining amount of a recording medium and detect the end position of the recording medium.

  As a method for detecting the remaining amount of a recording medium, a method is disclosed in which the angle of an arm provided in a recording medium supply unit of an image recording apparatus is detected (for example, Patent Document 1 and Patent Document 2). For example, in Patent Document 2, the remaining amount of the recording medium is detected by the following procedure. First, the initial position of the pickup roller that conveys the recording medium is detected by the light blocking flag blocking the initial position sensor. Next, the amount of change in the rotation angle of the shaft that rotates with the arm that supports the pickup roller is detected by the rotary encoder. Based on the detected change amount of the rotation angle of the arm and the number of conveyed recording media, a unit change amount of the rotation angle of the arm per recording medium is calculated, and based on the unit change amount, The remaining amount of the recording medium is calculated.

  Patent Document 3 discloses a method for detecting the remaining amount of a recording medium using an optical sensor. The image recording apparatus disclosed in Patent Document 3 includes a light emitting unit that emits infrared light and ultraviolet light, and a detector that detects the type of the recording medium and the presence or absence of the recording medium. . This detector is provided at a position facing the recording medium stacking unit. A reflection reference member is provided on the bottom surface of the recording medium stacking unit. Since the reflected light irradiated from the light emitting unit and reflected by the recording medium has different reflection characteristics depending on the type of the recording medium, the type of the recording medium is specified based on the reflected light. Further, when there is no recording medium in the recording medium stacking portion, the reflected light from the reflection reference member is received, and therefore it is determined that there is no recording medium in the mounting portion by the reflection characteristics of this member.

  Patent Document 4 discloses a method for detecting an end position of a recording medium using an optical sensor. The line printer disclosed in Patent Document 4 can reliably detect the size of a recording medium that is difficult to detect the size by reflected light. In this line printer, a transmissive optical sensor is provided in a carriage unit on which a recording head is mounted, and a detection plate is provided at a position to be a home position. In addition, a size detection plate is provided on the recording medium press for pressing the recording medium conveyed to the recording unit. When the carriage unit moves on the detection plate, the light emitted from the optical sensor is blocked by the plate, so that the home position is recognized. Similarly, the size detection plate provided on the recording medium presser is recognized by the optical sensor provided with the carriage unit. Then, the distance between the two detection plates is calculated as the size of the recording medium.

  Patent Document 5 discloses a method for detecting the width and thickness of a recording medium using an optical sensor. The image recording apparatus disclosed in Patent Document 5 has a multipurpose sensor. This multi-purpose sensor is mounted on a carriage together with a recording head, and has one infrared photodiode (hereinafter referred to as “infrared LED”) and two phototransistors. The infrared LED is a light emitting element arranged to irradiate light at an angle of 45 ° with respect to a measurement surface (platen surface or recording paper surface). The two phototransistors are light receiving elements arranged such that the light receiving axis is parallel to the central axis of the reflected light of the infrared LED. The two phototransistors are arranged with the optical axis shifted from the infrared LED. For this reason, the output voltages output from the two phototransistors greatly change according to the distance from the multipurpose sensor to the measurement surface. In this recording apparatus, when the output voltage of the phototransistor is obtained, the distance coefficient is obtained based on these two output voltages. The recording apparatus is provided with a table in which a distance coefficient obtained by calculation is associated with a distance from the multipurpose sensor to the measurement surface. Therefore, the distance from the multipurpose sensor to the recording paper and the distance from the multipurpose sensor to the platen are obtained based on the distance coefficient obtained as described above and the table, and the thickness of the recording paper is obtained from these. It is done.

JP 60-197540 A JP 2000-281242 A JP 2006-225058 A JP 11-138924 A JP 2007-91467 A

  As described above, in the image recording apparatus, it is desired that the remaining amount of the sheet placed on the sheet placement unit and the end position of the sheet on the platen are detected. For example, as disclosed in Patent Documents 1 to 4, an optical sensor for detecting the remaining amount of the sheet and an optical sensor for detecting the edge of the sheet are provided in the image recording apparatus, respectively. Both detections are realized. However, when the number of optical sensors increases, there arises a problem that the complexity of assembly, inspection, etc. due to an increase in the component cost points increases.

  In Patent Document 5, the width and thickness of a recording medium are calculated by one infrared LED and two phototransistors. However, these two types of detection are realized for a sheet on the platen, such as a sheet placed on a platen and a member placed at different positions such as a sheet on the platen. Each sheet is not detected.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to enable detection of the presence / absence of a sheet on the sheet placement portion and the width of the sheet on the platen by a set of optical sensors. Is to provide.

  Another object of the present invention is to prevent an image from being recorded on a sheet having a size different from the size designated by the user with a simple configuration.

  (1) An image recording apparatus according to the present invention is in contact with and away from a sheet placement portion having a placement surface on which a plurality of sheets are stacked and placed, and the placement surface of the sheet placement portion. A feeding means that is movable in the first direction and that contacts the uppermost sheet among the sheets placed on the sheet placing section, and feeds the sheet to the conveying path; A platen having a support surface for supporting the sheet fed to the conveying path, a conveying means for conveying the sheet to the platen, and disposed on the opposite side of the feeding means with the platen interposed in the first direction. A carriage that moves in a third direction along a support surface of the platen that intersects a second direction in which the sheet is conveyed on the platen, and a sheet that is mounted on the carriage and is on the platen To record images. A position detecting means for detecting the position of the carriage in the third direction and outputting position information indicating the position, and moving in the first direction in conjunction with the movement of the feeding means toward the platen. A light-emitting unit that emits light, a light-receiving unit that is mounted on the carriage and outputs a signal corresponding to the amount of light received by the light-emitting unit, and in the platen, the light-receiving unit extends in the third direction. A translucent portion that is provided along the moving region and transmits light emitted from the light emitting portion, and a virtual straight line along a first direction including the light emitting portion and the translucent portion intersect each other. In addition to the position, the pair of light shielding portions that are spaced apart from each other in the second direction and extend in directions intersecting with the third direction, and have a light transmittance lower than that of the light transmitting portion with respect to the first direction. And feeding the sheet from the sheet placement section Prior to this, the carriage is moved in a state in which the light emitting unit emits light, and the light emission is performed based on the second position in the third direction of the carriage when the light of the light emitting unit is attenuated by the light shielding unit. Calculating a third position of the sheet in the first direction, performing a first calculation for determining the presence / absence of a sheet in the sheet placement unit based on the third position, and having a sheet in the sheet placement unit On the condition that it is determined, when the sheet feeding unit is driven, the sheet is supported on the support surface of the platen from the sheet placement unit, and the sheet is on the translucent unit, and Before the image recording is performed on the sheet, the carriage is moved in a state in which the light emitting unit emits light, and the light receiving unit receives the light of the light emitting unit that has passed through the light transmitting unit. Based on the fourth position and the third position in the third direction of Yarijji comprises control means for performing a second operation determining width along the third direction of the sheet, a.

  The feeding unit moves in the first direction in accordance with the thickness of the plurality of sheets placed on the sheet placement unit. As the feeding unit moves, the light emitting unit also moves in the first direction. When the light emitting unit moves in the first direction, the light irradiated from the light emitting unit is attenuated once on the carriage side by the light shielding unit, and is again transmitted to the carriage side between the pair of light shielding units (second position). ) Will change. While the carriage is moved in the third direction, the light receiving unit detects a position where light is attenuated by the light blocking unit and then transmitted again, thereby detecting the second position. Based on the second position, the third position of the light emitting unit in the first direction is calculated. The control means calculates a third position prior to feeding the sheet from the sheet placement unit, and performs a first calculation for determining the presence or absence of a sheet in the sheet placement unit based on the third position. Then, the feeding unit is driven on the condition that it is determined that there is a sheet in the sheet placement unit. Accordingly, the feeding unit is not driven even though there is no sheet in the sheet placing portion.

  The sheet is conveyed in the second direction while being supported by the platen. The end of this sheet passes over the translucent part. Light emitted from the light emitting part and transmitted through the light transmitting part is shielded by the sheet. Accordingly, when the position of the end portion of the sheet changes, the position (fourth position) in the third direction of the position of the carriage that receives light transmitted from the light emitting part to the carriage side through the light transmitting part changes. The fourth position is detected by detecting the position at which the light receiving portion receives the light transmitted through the light transmitting portion while the carriage is moved in the third direction. Based on the fourth position and the third position described above, the position of the end of the sheet is determined. Based on the detected position of the edge of the sheet, the width of the sheet is calculated.

  In this specification, unless otherwise specified, the “direction” is represented by a straight line having a facing direction such as + and −, for example. For example, it is represented by an arrow having one arrow head such as + or-.

  (2) The control means performs an image recording operation based on image recording data including image information indicating an image to be recorded and size information indicating a size of a sheet on which the image data is to be recorded. Yes, on the condition that the width of the sheet obtained by the second calculation is different from the width of the sheet obtained from the size information, the sheet conveyed to the platen without the image recording is conveyed. It may be discharged from the road.

  Accordingly, a sheet having a size different from the size designated by the user is discharged from the conveyance path without performing image recording.

  (3) The control means may perform the first calculation and the second calculation for each sheet when continuously recording images on a plurality of sheets.

  For example, when sheets having different sizes are mixedly loaded on the sheet placement unit, a sheet having a size different from the size specified by the user is discharged from the conveyance path without performing image recording.

  (4) The control means may notify an error on the condition that it is determined in the first calculation that there is no sheet in the sheet placement unit.

  Thereby, the user can know the timing of replenishing the sheet placement unit with the sheet.

  (5) The control means may notify an error on condition that the width of the sheet obtained by the second calculation is different from the width of the sheet obtained from the size information. .

  Thereby, the user can know the necessity of exchanging the sheet | seat of a sheet | seat mounting part.

  (6) In the first calculation, the control unit may calculate an amount of the sheet placed on the sheet placement unit based on the third position.

  (7) As the control means, in the first calculation, a first distance along the third direction between the virtual straight line and the second position, and the distance between the first position and the pair of light shielding portions. A second distance along the third direction, a third distance along the first direction between the placement surface of the sheet placement portion and the support surface of the platen, and a support surface of the platen and a light receiving portion of the carriage. And calculating the third position based on the fourth distance along the first direction.

  (8) As said control means, in said 2nd calculation, said 1st of said 5th distance along said 3rd direction of said virtual straight line and said 4th position, said 3rd position, and the support surface of said platen The position of the end along the third direction of the sheet is calculated based on the sixth distance along the direction, the fourth distance, and the first position, and the width of the sheet based on the position of the end. Can be used.

  According to the present invention, the control unit performs the first calculation for determining the presence / absence of a sheet in the sheet placement unit based on the third position before feeding the sheet from the sheet placement unit, Since the feeding unit is driven on the condition that it is determined that there is a sheet in the placement unit, the feeding unit is not driven even though there is no sheet in the sheet placement unit. Further, since the control means performs the second calculation based on the third position and the fourth position and calculates the width of the sheet, the presence / absence of the sheet in the sheet placement portion is determined by one set of optical sensors, The width of the sheet on the platen is detected.

  According to the present invention, if the width of the sheet calculated by the second calculation is different from the width of the size specified by the user, the sheet is discharged from the conveyance path without performing image recording. Thus, it is possible to prevent image recording on a sheet having a size different from the size designated by the above, and it is possible to prevent the platen from being stained and the back surface of the sheet from being stained.

1 is an external perspective view of a multifunction machine 10 according to an embodiment of an image recording apparatus according to the present invention. 2 is a schematic diagram illustrating an internal structure of a printer unit 11. FIG. 2 is a plan view showing a main configuration of a printer unit 11. FIG. 3 is a plan view of a recording unit 24. FIG. 3 is a block diagram illustrating a configuration example of a control unit 100. FIG. It is a schematic diagram which represents typically the cross-sectional structure of the VI-VI cutting line of FIG. It is a schematic diagram which represents typically the cross-sectional structure of the VI-VI cutting line of FIG. It is a figure which shows the relationship of the points O, A, B, C, and D in FIG. It is a schematic diagram which represents typically the cross-sectional structure of the VI-VI cutting line of FIG. It is a figure which shows the relationship of the points O, A, B, E, and F in FIG. The amount of change in the amount of received light accompanying the movement of the carriage 38 is illustrated. 4 is a flowchart illustrating a printing operation of the printer unit 11. 6 is a flowchart illustrating an operation for determining a remaining sheet capacity N. 6 is a flowchart illustrating an operation for determining a remaining sheet capacity N. It is a flowchart which shows the determination operation | movement of a sheet | seat edge part.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as appropriate. In addition, this embodiment is only one aspect of the image recording apparatus according to the present invention, and it goes without saying that the embodiment may be changed without departing from the gist of the present invention.

[Schematic configuration of MFP 10]
As shown in FIG. 1, the multifunction machine 10 has a substantially rectangular parallelepiped shape that is longer in the width direction (third direction) 122 and the depth direction (second direction) 123 than in the height direction 121 (first direction). It is configured. The multifunction machine 10 is integrally provided with a printer unit 11 and a scanner unit 12, and has a print function, a scan function, a copy function, a facsimile function, and the like. The printer unit 11 corresponds to the image recording apparatus according to the present invention. The multifunction machine 10 does not necessarily have the scanner unit 12, and the image recording apparatus according to the present invention may be implemented as a single-function printer that does not have a scan function or a copy function.

  A printer unit 11 is provided in the lower part of the multifunction machine 10. The printer unit 11 can be communicably connected to an external information device (not shown) such as a personal computer. The printer unit 11 records an image on a recording sheet 110 (an example of the sheet of the present invention, see FIG. 2) based on print data received from an external information device or image data of a document read by the scanner unit 12.

  A scanner unit 12 is provided in the upper part of the multifunction machine 10. The scanner unit 12 functions as a so-called flatbed scanner. Since the scanner unit 12 is not directly related to the present invention, a detailed description is omitted here.

  An operation panel 14 is provided at the upper front of the multifunction machine 10. The operation panel 14 is provided with a display for displaying various types of information and buttons for receiving input of information. The multifunction machine 10 operates based on instruction information input from the operation panel 14. When the multifunction device 10 is connected to an external information device, the multifunction device 10 also operates based on instruction information transmitted from the external information device through a printer driver, a scanner driver, or the like.

[Printer 11]
Hereinafter, the configuration of the printer unit 11 will be described in detail.

  As shown in FIG. 1, an opening 13 is formed on the front side of the printer unit 11. A paper feed cassette 33 is attached to the printer unit 11 through the opening 13. The paper feed cassette 33 includes a paper feed tray 20 and a paper discharge tray 21. The paper feed tray 20 and the paper discharge tray 21 are arranged in two upper and lower stages with the paper discharge tray 21 as the upper side of the paper feed tray 20.

  The paper feed tray 20 has a container shape that can store the recording paper 110 in a stacked state. A standard size recording sheet 110 is accommodated in the sheet feeding tray 20. Examples of the recording paper 110 include plain paper, glossy paper, and ink jet paper. Examples of the standard size of the recording paper 110 include A4 size, B5 size, and postcard size. The paper feed tray 20 corresponds to the sheet placement unit in the present invention.

  An inclined plate 22 is provided on the back side (the right side in FIG. 2) of the paper feed tray 20. The inclined plate 22 is inclined so as to fall to the back side of the apparatus (the right side in FIG. 2). When the paper feed cassette 33 is attached to the printer unit 11, the inclined plate 22 is disposed below the conveyance path 23. The conveyance path 23 is directed upward from the inclined plate 22, then bends to the front side of the multifunction machine 10 (left side in FIG. 2), and linearly extends straight to the paper discharge tray 21.

  The paper feed tray 20 has a container shape, and a roller pocket 65 is provided on the bottom surface 27 thereof. The roller pocket 65 is disposed corresponding to a paper feed roller 25 described later, and has a concave fitting shape capable of accommodating a lower portion of the paper feed roller 25. When the recording paper 110 is placed on the bottom surface 27 of the paper feed tray 20, the roller pocket 65 is covered with the recording paper 110. When the recording paper 110 is removed from the paper feed tray 20, the roller pocket 65 is opened on the bottom surface 27, and the lower portion of the paper feed roller 25 is accommodated in the roller pocket 65. The bottom surface 27 corresponds to the mounting surface in the present invention.

  A supply unit 32 is disposed on the upper side of the paper feed tray 20. The supply unit 32 includes a paper feed roller 25, an arm 26, and a shaft 28. The shaft 28 is supported by a frame (not shown) of the printer unit 11 with the width direction 122 (direction perpendicular to the paper surface of FIG. 2, see FIG. 1) as the axial direction. The arm 26 is rotatably provided on the shaft 28. The paper feed roller 25 is rotatably supported on the distal end side of the arm 26. The arm 26 is urged to rotate toward the paper feed tray 20 by its own weight or receiving an elastic force from a spring or the like. Therefore, the paper feed roller 25 comes into contact with the uppermost recording paper 110 in the paper feed tray 20 with an appropriate pressure. Drive is transmitted to the paper feed roller 25 from an LF motor 85 (see FIG. 5) via a power transmission mechanism (not shown) provided on the shaft 28 and the arm 26. When the paper feed roller 25 rotates, the uppermost recording paper 110 on the paper feed tray 20 receives the rotational force of the paper feed roller 25 and is sent out along the inclined plate 22 to the transport path 23. As a result, the recording paper 110 is supplied from the paper feed tray 20 to the transport path 23. The supply unit 32 corresponds to a feeding unit in the present invention.

  In the conveyance path 23, a conveyance roller pair 59 is provided on the upstream side of a platen 42 described later. The conveyance roller pair 59 includes a conveyance roller 60 and a pinch roller 61. The conveyance roller 60 is driven by the LF motor 85 (see FIG. 5) and rotates. The pinch roller 61 is rotatably disposed below the conveyance roller 60 with the conveyance path 23 interposed therebetween, and is urged toward the conveyance roller 60 by a spring. The recording paper 110 supplied from the paper feed tray 20 to the conveyance path 23 is conveyed in the conveyance direction 17 by receiving the rotational force of the conveyance roller 60 while being sandwiched between the conveyance roller 60 and the pinch roller 61. The direction along the transport direction 17 matches the depth direction 123. This pair of transport rollers 59 corresponds to the transport means in the present invention.

  A discharge roller pair 64 is provided downstream of the conveyance roller pair 59 in the conveyance path 23 in the conveyance direction 17. The discharge roller pair 64 includes a discharge roller 62 and a spur 63. The paper discharge roller 62 is driven and transmitted from the LF motor 85 (see FIG. 5) and rotates in synchronization with the transport roller 60. The spur 63 is rotatably disposed above the paper discharge roller 62 with the conveyance path 23 interposed therebetween, and is urged by a spring toward the paper discharge roller 62. The recording paper 110 is transported along the transport path 23 under the rotational force of the paper discharge roller 62 while being sandwiched between the paper discharge roller 62 and the spur 63, and discharged to the paper discharge tray 21 (see FIG. 1). Is done.

  A registration sensor 71 is provided upstream of the conveyance roller pair 59 in the conveyance path 23 in the conveyance direction 17. The registration sensor 71 detects the presence or absence of the recording sheet 110 conveyed along the conveyance path 23. The registration sensor 71 is not particularly limited as long as the recording paper 110 can be detected, but is configured as a mechanical sensor in the present embodiment. The resist sensor 71 includes a photo interrupter and a detector. The photo interrupter includes a light emitting unit that emits light and a light receiving unit that receives light. The detector is pivotally supported by being in contact with the recording paper 110. When the recording paper 110 is not in contact with the detector, the optical path of light between the light emitting unit and the light receiving unit is opened. When the recording paper comes into contact with the detector, the optical path is blocked by the detector. For this reason, the signal level of the electric signal generated by the light receiving unit changes. The control unit 100 (see FIG. 5), which will be described later, determines the presence or absence of the recording paper 110 at the fifth position P5 based on the change in the electrical signal.

  As shown in FIG. 3, the transport roller 60 is provided with a rotary encoder 86. Specifically, the rotary encoder 86 includes an encoder disk 87 provided on the shaft of the transport roller 60 and a photo interrupter 88 that detects a pattern of the encoder disk 87. The encoder disk 86 has a disk shape made of a transparent resin. The encoder disk 86 has a pattern in which light-shielding portions and light-transmitting portions extending radially are arranged alternately at an equal pitch. The photo interrupter 88 detects the pattern of the encoder disk 86 and outputs a pulse signal.

[Platen 42]
A platen 42 is provided between the conveyance roller pair 59 and the discharge roller pair 64. The platen 42 is provided below the conveyance path 23. The recording paper 110 conveyed along the conveyance path 23 is supported from below by the platen 42 when passing below the recording unit 24. The platen 42 is provided with a light transmitting portion 52 (see FIG. 4). The upper surface of the light transmitting portion 52 is substantially flush with the sheet support surface 56 of the platen 42. The translucent part 52 is arranged on the upstream side in the transport direction 17 from the recording head 39 and is located immediately below the light receiving element 68 described later. Accordingly, the ink droplet 55 is not ejected from the recording head 39 toward the light transmitting portion 52.

  As shown in FIG. 4, the translucent part 52 is a window in which a transparent member is fitted in a through hole that penetrates the platen 42 in the height direction 121. This transparent member is not essential, but is useful for preventing the ink mist on the upper side of the platen 42 from flowing into the paper feed cassette 33 side. A light beam 54 (see FIGS. 6, 7, and 9), which will be described later, can pass through the light transmitting portion 52. In the plan view shown in FIG. 4, the width of the light transmitting portion 52 along the width direction 122 is wider than the width of the maximum size recording sheet 110 that can perform image recording in the printer portion 11. The recording sheet 110 transported onto the platen 42 is transported in the transport direction 17 with the center position in the width direction 122 aligned with the virtual center line 58. Such a transport method is also called a center register. One end in the width direction 122 of the recording paper 110 of all sizes capable of image recording in the printer unit 11 passes over the light transmitting unit 52. In other words, the translucent part 52 is not completely covered by the recording paper 110 conveyed on the platen 42.

  The light transmitting portion 52 is provided with a pair of light shielding lines 50A and 50B for shielding a light beam 54 described later. The intensity of the light beam 54 that can pass through the light transmitting part 52 in the height direction 121 is attenuated by the light shielding lines 50A and 50B. The light shielding lines 50 </ b> A and 50 </ b> B are straight lines extending in the direction along the transport direction 17 (depth direction 123), and the thickness of the light shielding lines 50 </ b> A and 50 </ b> B attenuates the light intensity of the light beam 54 toward the light receiving element 68. The thickness is sufficient to change the output electrical signal, and is sufficiently narrower than the width of the recording paper 110 and the translucent portion 52 along the width direction 122. The light shielding lines 50 </ b> A and 50 </ b> B do not need to completely block the light beam 54, and are sufficient to attenuate the intensity of the light beam 54 to the extent that it can be detected as a change in the electrical signal output from the light receiving element 68.

  The light shielding lines 50A and 50B are both disposed on the left side in FIG. 4 with respect to the virtual center line 58 in the width direction 122 of the platen 42. The arrangement of the pair of light shielding lines 50 </ b> A and 50 </ b> B may be interchanged with respect to the virtual center line 58. The light shielding lines 50A and 50B are provided at positions in the width direction 122 that do not overlap with the end of the recording paper 110 of a predetermined size conveyed by the center register. The predetermined size of the recording paper 110 is, for example, A4 size or A5 size defined by Japanese Industrial Standard.

  The pair of light shielding lines 50A and 50B are separated from each other in the width direction 122. The interval between the light shielding lines 50A and 50B is sufficient to detect the light flux 54 transmitted through the light shielding lines 50A and 50B and traveling toward the light receiving element 68 as a change in the electrical signal output from the light receiving element 68. It is sufficiently narrower than the width along the width direction 122 of the recording paper 110 or the translucent part 52. The arrangement of the pair of light shielding lines 50 </ b> A and 50 </ b> B is relative, and may be interchanged in the width direction 122.

[Carriage 38]
As shown in FIG. 2, the recording unit 24 is disposed above the platen 42. The recording unit 24 includes a carriage 38 that moves in the width direction 122 (direction perpendicular to the paper surface in FIG. 2). An ink jet recording head 39 and a light receiving element 68 (an example of a light receiving portion of the present invention) are mounted on the carriage 38. Here, the width direction 122 is a horizontal direction orthogonal to the conveyance direction 17 of the recording paper 110.

  As shown in FIG. 3, a pair of guide frames 43 and 44 are provided on the upper side of the transport path 23 with a predetermined interval in the transport direction 17. The guide frames 43 and 44 are extended in the width direction 122. The guide frame 43 is provided upstream of the guide frame 44 in the transport direction 17. The carriage 38 is placed on the guide frames 43 and 44 so as to straddle the guide frames 43 and 44. Thus, the carriage 38 is disposed to face the platen 42 with the conveyance path 23 interposed therebetween (see FIG. 2). In FIG. 2, the guide frames 43 and 44 are omitted.

  The upstream end of the carriage 38 in the transport direction 17 is slidably supported on the upper surface of the guide frame 43. The downstream end of the carriage 38 in the transport direction 17 is slidably supported on the upper surface of the guide frame 44. The end portion 45 of the guide frame 44 is formed by bending the guide frame 44 upward at a substantially right angle, and extends in the width direction 122. The carriage 38 sandwiches the end portion 45 with a roller (not shown) or the like. As a result, the carriage 38 can move in the width direction 122 with the end 45 as a reference.

  A belt drive mechanism 46 is provided on the upper surface of the guide frame 44. The belt drive mechanism 46 includes a drive pulley 47, a driven pulley 48, and a drive belt 49. The driving pulley 47 and the driven pulley 48 are respectively provided near both ends in the width direction 122. The drive belt 49 is an endless ring having teeth on the inner side, and is spanned between the drive pulley 47 and the driven pulley 48.

  A CR motor 84 (see FIG. 5) is connected to the shaft of the drive pulley 47. The drive pulley 47 rotates in response to the driving force of the CR motor 84. The drive belt 49 moves circumferentially by the rotational force of the drive pulley 47. Since the carriage 38 is fixed to the drive belt 49, the carriage 38 moves in the width direction 122 by the circumferential movement of the drive belt 49.

  An encoder strip 51 is provided on the guide rail 44. The encoder strip 51 is installed over both ends of the guide rail 44 along the end 45. The encoder strip 51 is in the form of a strip made of a transparent resin. The encoder strip 51 has a pattern in which light shielding portions and light transmitting portions are alternately arranged at an equal pitch. A photo interrupter 69 for detecting the pattern of the encoder strip 51 is mounted on the carriage 38. The photo interrupter 69 outputs a pulse signal corresponding to the pattern of the encoder strip 51.

[Recording head 39]
The recording head 39 is an ink jet recording head. An ink cartridge 40 (see FIG. 3) is disposed inside the printer unit 11. The ink cartridge 40 is provided with four types of ink cartridges 40 corresponding to cyan, magenta, yellow, and black ink colors. Each color ink is supplied from each ink cartridge 40 to the recording head 39 through four ink tubes 41. The recording head 39 is mounted on the carriage 38 such that the nozzles are exposed downward from the bottom surface of the carriage 38 (see FIG. 2). While the carriage 38 is moved in the width direction 122, minute ink droplets 55 are selectively ejected from the nozzles of the recording head 39 toward the recording paper 110 on the platen 42. As a result, an image is recorded on the recording paper 110 on the platen 42.

[Optical sensor 70]
As shown in FIG. 6, the optical sensor 70 includes a light emitting element 67 and a light receiving element 68. The light emitting element 67 is provided in the supply unit 32. Specifically, the light emitting element 67 is provided on the upper side of the base end portion of the arm 26 that supports the paper feed roller 25. The light emitting element 67 is a photodiode (hereinafter referred to as “LED”). A light beam 54 having a constant intensity is emitted from the light emitting element 67. The light beam 54 emitted from the light emitting element 67 passes through the light transmitting portion 52 provided on the platen 42. The light beam 54 is attenuated by the light shielding lines 50A and 50B. When the amount of the recording paper 110 loaded on the paper feeding tray 20 changes, the position of the uppermost recording paper 110 in the height direction 121 changes, and the paper feeding roller 25 and the arm 26 press against the uppermost recording paper 110. The height position of also changes. Therefore, the position of the light emitting element 67 in the height direction 121 is displaced according to the remaining amount of the recording paper 110 loaded on the paper feed tray 20. This light emitting element 67 corresponds to the light emitting portion in the present invention.

  The light receiving element 68 is mounted on the carriage 38 and faces the light transmitting portion 52. The light receiving element 68 is a phototransistor. The light receiving element 68 receives the light beam 54 irradiated from the light emitting element 67 and passed through the light transmitting portion 52, and outputs an electric signal corresponding to the amount of light received. This light receiving element 68 corresponds to the light receiving portion in the present invention.

[Control unit 100]
The control unit 100 comprehensively controls not only the printer unit 11 but also the entire operation of the multifunction machine 10. As illustrated in FIG. 5, the control unit 100 is configured as a microcomputer mainly including a CPU 101, a ROM 102, a RAM 103, an EEPROM 104, and an ASIC (Application Specific Integrated Circuit) 109. The control unit 100 functions as position detection means, first calculation means, and second calculation means in the present invention.

  The ROM 102 stores a program for the CPU 101 to control the entire MFP 10 including the CR motor 84 and the LF motor 85. The ROM 102 also has a program and a table for detecting the remaining amount of the recording paper 110 placed on the paper feed tray 20 and detecting the end of the recording paper 110 conveyed on the platen 42. Stored. This table associates the remaining amount of the recording paper 110 and the end position of the recording paper 110 on the platen with the position of the carriage 38 (first distance to sixth distance described later). The control unit 100 determines the remaining amount of the recording paper 110 and the end position of the recording paper 110 on the platen 42 based on a table stored in the ROM 102.

  The RAM 103 is used as a storage area for temporarily storing various data used when the CPU 101 executes the various programs described above or a work area for data processing or the like. The EEPROM 104 stores settings, flags, and the like that should be retained even after the power is turned off.

  Connected to the ASIC 109 are an optical sensor 70, a registration sensor 71, drive circuits 80 and 81, a linear encoder 82, a rotary encoder 83, and the like. Although not shown in FIG. 5, the ASIC 109 is also connected with a head control circuit for controlling the recording head 39, the scanner unit 12, the operation panel 14, various interfaces, and the like.

  The drive circuit 81 drives the LF motor 85. The drive circuit 81 receives the output signal from the ASIC 109 and drives the LF motor 85. The driving force of the LF motor 85 is transmitted to the paper feed roller 25, the transport roller 60, and the paper discharge roller 62 through a known drive transmission mechanism including a gear, a drive shaft, and the like.

  The drive circuit 80 supplies a drive signal to the CR motor 84 based on the phase excitation signal or the like input from the ASIC 109. When the CR motor 84 that receives this drive signal rotates, the carriage 38 is moved in the width direction 122 via the belt drive mechanism 46.

  The linear encoder 82 detects the encoder strip 51 by the photo interrupter 69 (see FIG. 3). The control unit 100 determines the position, speed, and orientation of the carriage 38 based on the detection signal of the linear encoder 82 and controls the driving of the CR motor 84. Coupled with the linear encoder 82, the control unit 100 constitutes a position detection means in the present invention.

  The rotary encoder 83 detects the encoder disk 87 by the photo interrupter 88 (see FIG. 3). The control unit 100 determines the amount of rotation of the transport roller 60 based on the detection signal of the rotary encoder 83 and controls the driving of the LF motor 85.

  The control unit 100 determines the presence or absence of the recording paper 110 at the fifth position P5 of the transport path 23 based on the change in the electrical signal output from the registration sensor 71 (see FIG. 2). Further, the control unit 100 determines the position of the leading edge or the trailing edge of the recording sheet 110 on the platen 42 from the rotation amount of the conveying roller 60 after the leading edge or the trailing edge of the recording sheet 110 passes the fifth position P5. .

[Operation of MFP 10]
The operation of the multifunction machine 10 will be described below (see FIG. 12).

  When the control unit 100 receives a print start command input on the operation panel 14 or a print start command from a computer or the like through a printer driver, the control unit 100 determines the remaining amount N of the recording paper 110 (S1). The determination of the remaining amount N will be described later. Based on the determination result, the control unit 100 determines whether or not to transport the recording paper 110 to the transport path 23 (S2). When there is no recording paper 110 in the paper feed tray 20 (S2: YES), that is, when the remaining amount N = 0, the control unit 100 ends the operation without performing printing. When the recording paper 110 is present in the paper feed tray 20 (S2: NO), the control unit 100 drives the LF motor 85 to feed the recording paper 110 from the paper feed tray 20 to the transport path 23 (S3). .

  The registration paper 71 detects the leading edge of the recording paper 110 fed to the transport path 23. The control unit 100 monitors the leading end position of the recording paper 110 based on the detection signal of the registration sensor 71 and the detection signal of the rotary encoder 83. When the leading end of the recording paper 110 slightly passes through the first position P1 (see FIG. 4) corresponding to the light transmitting portion 52, the control unit 100 stops the conveyance of the recording paper 110 and the width direction of the recording paper 110 The position of the end with respect to 122 is determined (S4). The determination of the edge position of the recording paper 110 will be described later. The first position P1 is an intersection position between the center of the transport direction 17 in the light transmitting portion 52 and the virtual center line 58 that is the same position as the transport direction 17.

  If the position of the edge of the recording paper 110 cannot be determined, the control unit 100 stops printing (S5: NO). When the end position of the recording sheet 110 is determined (S5: YES), the control unit 100 calculates the width of the recording sheet 110 based on the end position, and the sheet width based on the size information included in the print data. (S6). When the position of the edge of the recording paper 110 is not determined, the control unit 100 displays that fact on the display of the operation panel 14 or the screen of the external information device and ends the printing. In addition, when the width of the recording paper 110 based on the position of the end of the recording paper 110 is different from the paper width based on the size information included in the print data (S6: NO), the control unit 100 displays the display on the operation panel 14 This is displayed on the screen of the external information device, and printing is terminated. When printing is completed, the recording paper 110 conveyed to the platen 42 is discharged to the paper discharge tray 21.

  When the width of the recording sheet 110 based on the position of the end of the recording sheet 110 matches the sheet width based on the size information included in the print data (S6: YES), the control unit 100 performs printing on the recording sheet 110 (S7). . If image information for the next page exists (S8: YES), the control unit 100 prints the next page in the same manner as described above. If there is no image information for the next page (S8: NO), the control unit 100 ends printing.

[Determination of the remaining amount N of the recording paper 110]
Hereinafter, a method for determining the remaining amount N of the recording paper 110 will be described in detail (see FIG. 13).

  The controller 100 causes the light emitting element 67 to emit light (S11). Further, the control unit 100 moves the carriage 38 to the home position (hereinafter referred to as “HP”) (S12). Note that HP is one end side in the direction in which the carriage 38 reciprocates, and is the right side in FIG. Further, the end position (hereinafter referred to as “EP”) is the end opposite to the HP, and is the left side in FIG.

  Subsequently, the control unit 100 monitors the output signal of the light receiving element 68 mounted on the carriage 38 while moving the carriage 38 moved to the HP toward EP. As shown in FIG. 6, in the process in which the carriage 38 is moved from the virtual center line 58 to the EP, the light receiving element 68 passes through the light transmitting portion 52 of the platen 42 between the pair of light shielding lines 50 </ b> A and 50 </ b> B. Is received. When the light receiving element 68 receives the light beam 54, a voltage corresponding to the amount of received light is output as a signal C.

As shown in FIG. 11A, the light receiving element 68 that has received the light beam 54 passing through the light transmitting portion 52 outputs a signal C (C ≧ C ₁ ) having a voltage higher than a preset threshold value C _1. . When the light beam 54 is attenuated by the first run of the light shielding lines 50A, the light receiving element 68 outputs a signal of small voltage than the threshold _{C 1 C (C <C 1} ) (S14: YES). When the carriage 38 is further moved (S15), the light receiving element 68, a pair of light shielding lines 50A, receives the light beam 54 passing through the inter-50B, the threshold _{C 1} signal of a voltage greater than C (C ≧ _C 1) Is output (S16: YES). The control unit 100 stores the position information of the carriage 38 at that time.

When the carriage 38 is further moved (S17) and the light beam 54 is attenuated by the second light shielding line 50B, the light receiving element 68 outputs a signal C (C <C ₁ ) having a voltage smaller than the threshold value C ₁ ( S18: YES).

  When the carriage 38 is further moved (S19) and the carriage 38 reaches EP (S20: YES), the control unit 100 turns off the light emitting element 67 (S21), and based on the stored position information, the recording paper is recorded. The remaining amount N of 110 is calculated (FIG. 14: S22).

  Hereinafter, a method for calculating the remaining amount N of the recording paper 110 will be described in detail. As shown in FIG. 6, the light emitting element 67 is arranged on the imaginary straight line 53 along the height direction 121 including the first position P <b> 1 of the platen 42 in the cross section along the height direction 121 and the width direction 122. ing. A position in the width direction 122 of the carriage 38 when the light beam 54 emitted from the light emitting element 67 passes through the pair of light shielding lines 50A and 50B and is detected by the light receiving element 68 is defined as a second position P2. The position of the light emitting element 67 in the height direction 121 is defined as a third position P3. The position of the light emitting element 67 is a point O. An intersection point between the virtual straight line 53 and the sheet support surface 56 of the platen 42 is defined as a point A. A point B is an intersection of the virtual straight line 53 and the scanning surface 57 of the light receiving element 68. A center position in the width direction 122 between the light shielding lines 50A and 50B is a point C. Let the second position P2 be a point D.

  As shown in FIG. 8, in the planes along the height direction 121 and the width direction 122, ∠OAC = ∠OBD = 90 ° and 2 which are similar to each other by the three points OAC and the three points OBD. Two right triangles are formed respectively.

  A distance between the second position P2 (point D) and the point B is defined as a first distance L1. A distance between the point C and the first position P1 (point A) is a second distance L2. A distance between the light emitting element 67 and the sheet support surface 56 of the platen 42 when the paper feeding roller 25 is partially accommodated in the roller pocket 65 is a third distance L3 (see FIG. 7). A distance between the sheet support surface 56 of the platen 42 and the scanning surface 57 of the light receiving element 68 is defined as a fourth distance L4.

  As shown in FIG. 8, the first distance L1 is represented by a side BD in the triangle OBD. The second distance L2 is represented by the side AC in the triangle OAC. The fourth distance L4 is represented by a side AB corresponding to the difference between the side OA and the side OB in the triangle OAC and the triangle OBD. The values of the side AC (second distance L2), the side AB (fourth distance L4), and the third distance L3 are constant regardless of the remaining amount N of the recording paper 110 stacked on the paper feed tray 20, and are the printer unit. It is grasped in advance from 11 configurations. The side BD (first distance L1) changes according to the remaining amount N of the recording paper 110. When the remaining amount N of the recording paper 110 is large, the first distance L1 increases, and when the remaining amount N is small, the first distance L1 decreases.

  Since the triangle OAC and the triangle OBD are similar to each other, the relationship of Expression (1) is established.

  OA: AC = OB: BD ... Formula (1)

  Further, since the fourth distance L4 is represented by the side AB, the relationship of the expression (2) is established.

  OB = OA + AB ... Formula (2)

  By substituting equation (2) into OB of equation (1), it can be transformed as the following equation (3).

  OA * BD = AC * (OA + AB) ... Formula (3)

  When Expression (3) is represented by OA, it can be transformed as the following Expression (4).

  OA = AB * AC / (BD-AC) ... Formula (4)

  The remaining amount N of the recording paper 110 is calculated by excluding the side OA in the triangle OAC from the third distance L3. Therefore, the following formula (5) is established. The remaining amount N is grasped as the thickness along the height direction 121 of the plurality of recording sheets 110 placed on the sheet feeding tray 20, and the remaining amount N is included up to the depth of the roller pocket 65. It will be.

  N = L3-OA Formula (5)

  By substituting the OA of the formula (4) for the OA of the formula (5), the formula (6) is derived.

  N = L3- {AB × AC / (BD-AC)} (6)

  Thereby, when the first distance L1 is detected, the remaining amount N of the recording paper 110 is calculated.

As shown in FIG. 14, the control unit 100 determines whether the remaining amount N of the recording sheet 110 to be detected is _{X 1} or more (S24). Wherein, X ₁ is the maximum loading value corresponding to the remaining N to be 30%置量of the recording sheet 110 in the sheet feeding tray 20. That is, the control unit 100 determines whether or not the remaining amount N of the recording paper 110 is 30% or more of the maximum load capacity.

When the remaining amount N of the recording paper 110 is X ₁ ≦ N (S23: YES), the control unit 100 stores in the RAM 103 as remaining amount information that the remaining amount of the recording paper 110 is sufficient (S24).

Control unit 100, if the remaining amount N is less than _{X 1} of the recording paper 110 (S23: NO), determines (S25) whether the remaining N is greater than _{X 0.} Here, X ₀ is a value corresponding to the remaining amount N when there is no recording paper 110 in the paper feed tray 20, and is specifically set as a value less than the depth of the roller pocket 65. If the remaining amount N of the recording paper 110 is X ₀ <N <X ₁ (S25: YES), the control unit 100 determines that the remaining amount N of the recording paper 110 is less than 30% of the maximum load amount, and The result is displayed as a warning (S26). This warning is given on the display of the operation panel 14 or the screen of the external information device, and indicates that the remaining amount of the recording paper 110 loaded on the paper feed tray 20 is low.

Control unit 100, if the remaining amount N of the recording sheet 110 is _{X 0} or less (S25: NO), it is determined that the recording paper 110 in the paper feed tray 20 is not present, and the result is displayed as a warning (S27 ).

[Determination of the edge of the recording paper 110]
Hereinafter, a method of determining the edge position of the recording paper 110 will be described in detail (see FIG. 15).

  As described above, when the recording paper 110 is present in the paper feed tray 20, the recording paper 110 is fed to the conveyance path 23, and the recording paper 110 reaches the platen 42. Based on the outputs of the registration sensor 71 and the rotary encoder 83, the controller 100 determines that the leading edge of the recording paper 110 has reached a position that covers the light transmitting part 52 of the platen 42 (S31).

When the recording sheet 110 reaches the light transmitting section 52 (S31: YES), the control unit 100 stops conveying the recording sheet 110. Next, the control unit 100 causes the light emitting element 67 to emit light (S32). The control unit 100 moves the carriage 38 to HP (S33) and then moves the carriage 38 to EP. When the carriage 38 moves from the virtual center line 58 to the EP side, the control unit 100 monitors the output signal of the light receiving element 68. In the process in which the carriage 38 reaches the EP from the virtual center line 58, the light receiving element 68 detects the light beam 54 passing through the light transmitting portion 52 (S34). As before, the threshold C ₂ is set for the signal C the light receiving element 68 is outputted (refer to FIG. 11 (B)). This threshold value C ₂ is set higher than the threshold value C ₁ because the light beam 54 transmitted through the recording paper 110 applied to the light transmitting portion 52 is taken into consideration. When the signal C of the light receiving element 68 exceeds the threshold value _{C 2} (S35: YES), the control unit 100 acquires the position information of the carriage 38, and stored in RAM 103. When the carriage 38 reaches EP, the control unit 100 turns off the light emitting element 67 (S36), and calculates the position of the end of the recording paper 110 based on the stored position information (S37).

  Hereinafter, a method of calculating the edge position of the recording paper 110 will be described in detail.

  As shown in FIG. 9, when the light beam 54 emitted from the light emitting element 67 passes through the light transmitting portion 52 and is detected by the light receiving element 68 in the cross section along the height direction 121 and the width direction 122. The position of the carriage 38 is a fourth position P4. An intersection point between the end of the recording paper 110 in the width direction 122 of the light transmitting portion 52 and the light beam 54 is defined as a point E. Let the fourth position P4 be a point F.

  As shown in FIG. 10, in the plane along the height direction 121 and the width direction 122, ∠OAE = ∠OBF = 90 ° by the three-point OAE and the three-point OBF, and 2 similar to each other Two right triangles are formed.

  A distance between the fourth position P4 (point F) and the point B is a fifth distance L5. The distance between the third position P3 (point O) and the platen sheet support surface 56 (point A) is defined as a sixth distance L6. The distance between the sheet support surface 56 (point A) of the platen 42 and the scanning surface 57 (point B) of the light receiving element 68 is defined as a fourth distance L4.

  As shown in FIG. 10, the fifth distance L5 is represented by a side BF in the triangle OBF. The sixth distance L6 is represented by a side OA in the triangle OAE. The fourth distance L4 is represented by a side AB corresponding to the difference between the side OA and the side OB in the triangle OAE and the triangle OBF. Here, the side AB (fourth distance L4) is constant and is grasped in advance from the configuration of the printer unit 11. The side BF (the fifth distance L5) changes according to the position of the end of the recording paper 110. When the width of the recording paper 110 is wide, the fifth distance L5 is large, and when the width is narrow, the fifth distance is small.

  Since the triangle OAE and the triangle OBF are similar to each other, the relationship of Expression (7) is established.

  OA: AE = OB: BF ... Formula (7)

  The fourth distance L4 is represented by side AB. Therefore, the relationship of Expression (2) is established.

  OB = OA + AB ... Formula (2)

  By substituting equation (2) into OB of equation (7), it can be transformed as the following equation (8).

  OA × BF = AE × (OA + AB) (8)

  Since the distance required to detect the position of the end of the recording paper 110 is AE, when Expression (9) is transformed and expressed as AE, Expression (9) is obtained.

  AE = OA * BF / (OA + AB) ... Formula (9)

  Since the side OA is expressed by Expression (4), when OA of Expression (4) is substituted into Expression (9), it is expressed as Expression (10).

  AE = AC × BF / BD (Equation 10)

As described above, since the recording sheet 110 is conveyed by the center register, the distance L _s corresponding to the width of the recording sheet 110 is expressed by the equation (11).

L _s = 2 × AE Equation (11)

  By substituting AE in Expression (10) for AE in Expression (11), Expression (12) used for calculating the position of the edge of the recording paper 110 is derived.

L _s = 2 × AC × BF / BD Formula (12)

[Operational effects of this embodiment]
According to the present embodiment, the light beam 54 transmitted from the light emitting element 67 to the carriage 38 through the pair of light shielding lines 50A and 50B is received by the light receiving element 68 mounted on the carriage 38, and the second position P2 thereof is linear. It is detected by the encoder 82. Since the third position P3 with respect to the height direction 121 of the light emitting element 67 is calculated based on the second position P2, the remaining amount N of the recording paper 110 in the paper feed tray 20 is calculated by the one set of optical sensors 70. Is detected.

  A light beam 54 emitted from the light emitting element 67 and transmitted through the light transmitting portion 52 is received by the light receiving element 68 mounted on the carriage 38, and the fourth position P 4 is detected by the linear encoder 82. Since the end position of the recording sheet 110 is determined based on the fourth position P4 and the third position P3 described above, the end of the recording sheet 110 on the platen 42 is detected by one set of optical sensors 70. The position of the part is detected. When the end position of the recording paper 110 is detected by the control unit 100, the recording unit 24 can execute accurate borderless printing on the recording paper 110 that can be transported to the transport path 23.

[Modification]
In the above-described embodiment, the control unit 100 irradiates the light flux 54 from the light emitting element 67 and the carriage 38 at a timing at which the recording paper 110 is intermittently conveyed after the recording paper 110 is conveyed to the platen 42. are moved from the HP to EP, it may monitor whether the light receiving element 68 outputs a threshold value C ₂ or more signal C in the width of the recording paper 110.

Control unit 110, when the light-receiving element 68 in the width of the recording sheet 110 has output a threshold C ₂ or more signals C, it is determined that there is a hole in the recording paper 110, and the result is displayed as a warning. Further, the control unit 110 specifies the position and size of the hole and stores them in the RAM 103 in the same manner as the specification of the end position of the recording paper 110 described above, and ink droplets are applied to the hole or the periphery thereof. You may control the operation | movement of the recording head 39 so that it may not discharge.

11: Printer unit (image recording device)
20 ... Paper feed tray (sheet placement section)
23 ... conveying path 27 ... bottom surface (mounting surface)
32 ... Supply section (feeding means)
38 ... Carriage 39 ... Recording head 42 ... Platens 50A, 50B ... Shading line (shading part)
52 ... translucent portion 53 ... virtual straight line 56 ... sheet support surface (support surface)
59... Conveying roller pair (conveying means)
67... Light emitting element (light emitting part)
68. Light receiving element (light receiving part)
82 ... Linear encoder (position detection means)
100: Control unit (position detection means, control means)
110: Recording paper (sheet)
121 ... Height direction (first direction)
122... Width direction (third direction)
123 ... depth direction (second direction)

Claims (8)

A sheet placement section having a placement surface on which a plurality of sheets are stacked and placed;
The sheet can be moved in a first direction that is in contact with and away from the placement surface of the sheet placement unit, and contacts the uppermost sheet among the sheets placed on the sheet placement unit to convey the sheet. A feeding means for feeding to,
A platen having a support surface for supporting a sheet fed from the placement unit to the conveyance path;
Conveying means for conveying the sheet to the platen;
The platen is disposed on the opposite side to the feeding means with respect to the first direction, and intersects with the second direction in which the sheet is conveyed on the platen and along the support surface of the platen. A carriage that moves in a third direction;
A recording head mounted on the carriage for recording an image on a sheet on the platen;
Position detecting means for detecting the position of the carriage in the third direction and outputting position information indicating the position;
A light emitting unit that is moved in the first direction in conjunction with the movement of the feeding unit and that emits light toward the platen;
A light receiving unit mounted on the carriage and outputting a signal corresponding to the amount of light received by the light emitting unit;
In the platen, the light receiving portion is provided along a region moving in the third direction, and a light transmitting portion that transmits light emitted from the light emitting portion;
In addition to the first position where the imaginary straight line along the first direction including the light emitting portion and the light transmitting portion intersect, the virtual straight line is disposed apart from the second direction and extends in the direction intersecting the third direction. A pair of light shielding portions having a light transmittance lower than that of the light transmitting portion with respect to the first direction;
Prior to feeding a sheet from the sheet placing unit, the carriage is moved in a state where the light emitting unit emits light, and the third direction of the carriage when the light of the light emitting unit is attenuated by the light shielding unit Based on the second position, the third position in the first direction of the light emitting unit is calculated, and based on the third position, the first calculation for determining the presence or absence of the sheet in the sheet placement unit, On the condition that it is determined that there is a sheet in the sheet placement unit, the feeding unit is driven,
The light emitting unit emits light when the sheet is supported on the support surface of the platen from the sheet placing unit and the sheet is on the light transmitting unit and before image recording is performed on the sheet. Based on the fourth position and the third position in the third direction of the carriage when the light-receiving unit receives the light of the light-emitting unit that has passed through the light-transmitting unit in a state where the carriage is moved. An image recording apparatus comprising: a control unit that performs a second calculation for determining a width along the third direction of the sheet. The control means includes
An image recording operation is performed based on image recording data including image information indicating an image to be recorded and size information indicating a size of a sheet on which the image data is to be recorded.
On the condition that the width of the sheet obtained by the second calculation is different from the width of the sheet obtained from the size information, the sheet conveyed to the platen without image recording is removed from the conveyance path. The image recording apparatus according to claim 1, which is to be discharged.   The image according to claim 1 or 2, wherein the control means performs the first calculation and the second calculation for each sheet when continuously recording images on a plurality of sheets. Recording device.   4. The image recording apparatus according to claim 1, wherein the control unit performs error notification on a condition that it is determined in the first calculation that there is no sheet in the sheet placement unit. 5.   5. The control unit according to claim 1, wherein the control unit performs error notification on condition that a sheet width obtained by the second calculation is different from a sheet width obtained from the size information. The image recording apparatus according to any one of the above.   6. The image recording according to claim 1, wherein in the first calculation, the control unit calculates an amount of a sheet placed on the sheet placing unit based on the third position. apparatus.   In the first calculation, the control means includes a first distance along the third direction between the virtual straight line and the second position, and the third direction between the first position and the pair of light shielding portions. A third distance along the first direction between the placement surface of the sheet placement portion and the support surface of the platen, and the first distance between the support surface of the platen and the light receiving portion of the carriage. The image recording apparatus according to claim 1, wherein the third position is calculated based on a fourth distance along one direction. In the second calculation, the control means includes a fifth distance along the third direction between the virtual straight line and the fourth position, and along the first direction between the third position and the support surface of the platen. The position of the edge along the third direction of the sheet is calculated based on the sixth distance, the fourth distance, and the first position, and the width of the sheet is calculated based on the position of the edge. The image recording apparatus according to claim 1, wherein the image recording apparatus is one.

Images