Sheet feeding apparatus, image forming apparatus, and extension supporting unit

Abstract

A sheet feeding apparatus includes a first sheet supporting unit including a first sheet supporting surface configured to support a sheet, a feeding portion configured to feed the sheet supported on the first sheet supporting surface in a sheet feeding direction, and a second sheet supporting unit detachably attached to the first sheet supporting unit, and including a second sheet supporting surface configured to support a sheet and positioned upstream of the first sheet supporting surface in the sheet feeding direction in an attached state attached to the first sheet supporting unit. The second sheet supporting surface is narrower than the first sheet supporting surface in a width direction orthogonal to the sheet feeding direction, and longer than the first sheet supporting surface in the sheet feeding direction.

Description

BACKGROUNDField of the Technology

[0001] The present disclosure relates to a sheet feeding apparatus for feeding sheets, an image forming apparatus equipped with the sheet feeding apparatus, and an extension supporting unit adopted in the sheet feeding apparatus.Description of the Related Art

[0002] Japanese Patent Application Laid-Open Publication No. 2015-134688 discloses an image forming apparatus equipped with a manual feed tray on which sheets can be placed. Users can feed sheets through the manual feed tray to an image forming unit of the image forming apparatus. In this image forming apparatus, there may be a case where a sheet having a sheet length size that exceeds a sheet size that can be placed flatly on the manual feed tray in a sheet feed direction, for example, approximately longer than 450 mm, hereinafter referred to as a long sheet, is placed on the manual feed tray. In order to allow such a long sheet to be placed on the manual feed tray, a configuration is disclosed where an attachment corresponding to a long sheet is attached for placing a long sheet on a manual feed tray in a manner enclosing the manual feed tray from an outer side.

[0003] However, according to the configuration disclosed in Japanese Patent Application Laid-Open Publication No. 2015-134688, when attaching the attachment to the manual feed tray, the attachment is attached in a manner enclosing the manual feed tray from the outer side, such that the size in a sheet width direction of the entire manual feed tray after attachment is increased.SUMMARY

[0004] The present disclosure provides a sheet feeding apparatus, an image forming apparatus, and an extension supporting unit that are downsized in the sheet width direction.

[0005] According to a first aspect of the present disclosure, a sheet feeding apparatus includes a first sheet supporting unit including a first sheet supporting surface configured to support a sheet, a feeding portion configured to feed the sheet supported on the first sheet supporting surface in a sheet feeding direction, a second sheet supporting unit detachably attached to the first sheet supporting unit, and including a second sheet supporting surface configured to support a sheet and positioned upstream of the first sheet supporting surface in the sheet feeding direction in an attached state attached to the first sheet supporting unit. The second sheet supporting surface is narrower than the first sheet supporting surface in a width direction orthogonal to the sheet feeding direction, and longer than the first sheet supporting surface in the sheet feeding direction.

[0006] According to a second aspect of the present disclosure, an image forming apparatus includes the sheet feeding apparatus, and an image forming unit configured to form an image on a sheet.

[0007] According to a third aspect of the present disclosure, an extension supporting unit detachably attached to a sheet supporting unit including a first sheet supporting surface configured to support a sheet includes a second sheet supporting surface configured to support a sheet and positioned upstream of the sheet supporting surface in a sheet feeding direction by a feeding portion in an attached state attached to the sheet supporting unit. The second sheet supporting surface is narrower than the first sheet supporting surface in a width direction orthogonal to the sheet feeding direction, and longer than the first sheet supporting surface in the sheet feeding direction.

[0008] Features of the present disclosure will become apparent from the following description of embodiments with reference to the attached drawings. The following description of embodiments is described by way of example.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a cross-sectional view illustrating an image forming apparatus according to an embodiment.

[0010] FIG. 2 is a block diagram illustrating a control system of the image forming apparatus according to the embodiment.

[0011] FIG. 3 is a perspective view illustrating a feeding portion according to the embodiment.

[0012] FIG. 4 is a perspective view illustrating an extension unit according to the embodiment.

[0013] FIG. 5A is a perspective view of a state prior to attachment of a manual sheet feed unit and an extension unit according to the embodiment.

[0014] FIG. 5B is a perspective view of a state after attachment of the manual sheet feed unit and the extension unit according to the embodiment.

[0015] FIG. 6A is a perspective view of a state in which a long sheet is supported on the manual sheet feed unit having the extension unit according to the embodiment attached thereto.

[0016] FIG. 6B is a front view of a state in which a long sheet is supported on the manual sheet feed unit having the extension unit according to the embodiment attached thereto.

[0017] FIG. 7A is a perspective view of a state in which a regular size sheet is supported on the manual sheet feed unit having the extension unit according to the embodiment attached thereto.

[0018] FIG. 7B is a front view of a state in which a regular size sheet is supported on the manual sheet feed unit having the extension unit according to the embodiment attached thereto.

[0019] FIG. 8 is an exploded perspective view illustrating the extension unit according to the embodiment.

[0020] FIG. 9A is an exploded perspective view illustrating an attachment portion of the extension unit according to the embodiment.

[0021] FIG. 9B is a perspective view illustrating the attachment portion of the extension unit according to the embodiment.

[0022] FIG. 10A is an exploded perspective view illustrating the extension unit according to the embodiment.

[0023] FIG. 10B is a detail view illustrating the extension unit according to the embodiment.

[0024] FIG. 11 is a plan view illustrating a state in which hooks are at a closed position in the attachment portion of the extension unit according to the embodiment.

[0025] FIG. 12 is a plan view illustrating a state in which the hooks are at an opened position in the attachment portion of the extension unit according to the embodiment.

[0026] FIG. 13A is a perspective view illustrating an attached portion of the manual sheet feed unit according to the embodiment.

[0027] FIG. 13B is a plan view illustrating the attached portion of the manual sheet feed unit according to the embodiment.

[0028] FIG. 13C is a cross-sectional view illustrating the attached portion of the manual sheet feed unit according to the embodiment.

[0029] FIG. 14 is a plan view illustrating a state prior to having the hooks come into contact with hook engagement walls when attaching the attachment portion of the extension unit to the attached portion of the manual sheet feed unit according to the embodiment.

[0030] FIG. 15 is a plan view illustrating a state in which the hooks are in contact with the hook engagement walls and pivoted when attaching the attachment portion of the extension unit to the attached portion of the manual sheet feed unit according to the embodiment.

[0031] FIG. 16 is a plan view illustrating a state in which the attachment portion of the extension unit is attached to the attached portion of the manual sheet feed unit according to the embodiment.

[0032] FIG. 17 is a plan view illustrating a state in which the hooks are opened when detaching the attachment portion of the extension unit from the attached portion of the manual sheet feed unit according to the embodiment.

[0033] FIG. 18 is a plan view illustrating a state in which the hooks are disengaged from the hook engagement walls when detaching the attachment portion of the extension unit from the attached portion of the manual sheet feed unit according to the embodiment.

[0034] FIG. 19 is a plan view illustrating a state in which the attachment portion of the extension unit is detached from the attached portion of the manual sheet feed unit according to the embodiment.

[0035] FIG. 20 is a perspective view of the manual sheet feed unit according to the embodiment.

[0036] FIG. 21 is a perspective view in which a rack and pinion mechanism for moving a side regulating plate of the manual sheet feed unit according to the embodiment is viewed from a lower side.

[0037] FIG. 22 is a perspective view illustrating a trailing edge detection unit of the manual sheet feed unit according to the embodiment.

[0038] FIG. 23A is a cross-sectional view illustrating a trailing edge detection flag of the manual sheet feed unit according to the embodiment, wherein the trailing edge detection flag is positioned at a protruded position.

[0039] FIG. 23B is a cross-sectional view illustrating the trailing edge detection flag of the manual sheet feed unit according to the embodiment, wherein the trailing edge detection flag is positioned at a retracting position.

[0040] FIG. 24A is a cross-sectional view illustrating the trailing edge detection flag of the manual sheet feed unit according to the embodiment, wherein an A4 size sheet is supported.

[0041] FIG. 24B is a cross-sectional view illustrating the trailing edge detection flag of the manual sheet feed unit according to the embodiment, wherein an A3 size sheet is supported.

[0042] FIG. 25 is a flowchart illustrating a procedure for feeding sheets using the manual sheet feed portion according to the embodiment.

[0043] FIG. 26 is a cross-sectional view illustrating a state of the trailing edge detection flag in a state where a long sheet is supported on the manual sheet feed unit according to the embodiment.

[0044] FIG. 27 is a flowchart illustrating a procedure for feeding a long sheet using the manual sheet feed portion according to the embodiment.

[0045] FIG. 28 is a flowchart illustrating a procedure for feeding a long sheet using the manual sheet feed portion according to the embodiment, wherein a sheet width is also determined.DESCRIPTION OF THE EMBODIMENTS

[0046] An image forming apparatus 1 according to the present embodiment will be described below with reference to FIGS. 1 to 28. At first, a schematic configuration of the image forming apparatus 1 according to the present embodiment will be described with reference to FIG. 1. FIG. 1 is a cross-sectional view illustrating a schematic configuration of the image forming apparatus 1 according to the present embodiment taken from a front side. The image forming apparatus 1 is a tandem-type, intermediate transfer-type laser beam printer adopting an electrophotographic process. The image forming apparatus 1 can form and output a full-color or mono-color image corresponding to a print image data output from a host device 24 (refer to FIG. 2) connected to a control unit 20 on a sheet S serving as a recording medium.Image Forming Apparatus

[0047] The image forming apparatus 1 includes an apparatus body 201A, and an image forming unit 201B for forming an image on the sheet S. An image reading apparatus 202 arranged approximately parallelly is disposed above the apparatus body 201A. A discharge space V for discharging sheets is formed between the image reading apparatus 202 and the apparatus body 201A.Sheet Feed Unit

[0048] The sheets S are stored in sheet feed cassettes 7A and 7B of cassette sheet feed units 9A and 9B according to size, or supported on a manual sheet feed portion 40.

[0049] The cassette sheet feed units 9A and 9B include the sheet feed cassettes 7A and 7B that store the sheets S and feeding portions 6A and 6B that feed the sheets S from the sheet feed cassettes 7A and 7B. The cassette sheet feed units 9A and 9B store different size sheets S, but the configurations of the respective feeding portions 6A and 6B are similar, such that the feeding portion 6A will be described below. The feeding portion 6A includes a pickup roller 2, and a separation roller pair 5 composed of a feed roller and a retard roller for separating the sheet S delivered from the pickup roller 2. The sheet S separated one by one by the separation roller pair 5 is conveyed by a first pre-registration roller pair 11 to a registration roller pair 13.

[0050] The manual sheet feed portion 40 is an example of a sheet feeding apparatus, and includes a manual sheet feed unit 50, a feeding portion 41, and an extension unit 60. According to the present embodiment, in the manual sheet feed unit 50, a direction in which the supported sheets S are fed is referred to as a sheet feeding direction Df, and a direction orthogonal to the sheet feeding direction Df, that is, a width direction of the supported sheet S is referred to as a sheet width direction W.

[0051] The manual sheet feed unit 50 is an example of a first sheet supporting unit and a sheet supporting unit, and includes a manual feed tray 51, and a first sheet supporting surface 52 formed on an upper surface of the manual feed tray 51 and supporting the sheet S. The manual sheet feed unit 50 is openable and closable by pivoting with respect to the apparatus body 201A, and it is displaceable in a closed position and an opened position. The manual feed tray 51 supports the sheet S stacked on the first sheet supporting surface 52 in the opened state. Further, the manual feed tray 51 includes a pair of side regulating plates 53 that are disposed movably in the sheet width direction W on the manual sheet feed unit 50 and that regulate the position of a sheet supported on the first sheet supporting surface 52 by coming into contact with end portions of the sheet in the sheet width direction W. An air blow fan unit not shown for separating the sheets may be disposed on the side regulating plates 53.

[0052] FIG. 3 is a perspective view illustrating the manual sheet feed unit 50 and the feeding portion 41 according to the present embodiment. As illustrated in FIG. 3, the feeding portion 41 feeds the sheet S supported on the first sheet supporting surface 52 of the manual feed tray 51 to a second pre-registration roller pair 12. The feeding portion 41 includes a pickup roller 42, and a separation roller pair 43 composed of a feed roller and a retard roller for separating the sheet S delivered from the pickup roller 42. The sheet S separated one by one by the separation roller pair 43 is conveyed by the second pre-registration roller pair 12 to the registration roller pair 13. That is, the feeding portion 41 feeds the sheet S supported on the first sheet supporting surface 52 to the sheet feeding direction Df.

[0053] As illustrated in FIG. 1, the extension unit 60 is an example of a second sheet supporting unit and an extension supporting unit, and is detachably attached to the manual sheet feed unit 50 in a direction along the sheet feeding direction Df. In an attached state attached to the manual sheet feed unit 50, the extension unit 60 is positioned upstream of the manual feed tray 51 in the sheet feeding direction Df and supports the sheet S. The extension unit 60 includes a first supporting portion 61, a second supporting portion 62, a bending portion 63, and an end portion 62c, which is a most upstream end in a sheet feeding direction Df. The first supporting portion 61 includes a second sheet supporting surface 61a that is extended upstream in the sheet feeding direction Df from the first sheet supporting surface 52. The second supporting portion 62 includes a third sheet supporting surface 62a that is arranged upstream of the second sheet supporting surface 61a in the sheet feeding direction Df and that supports a long sheet SL together with the first sheet supporting surface 52 and the second sheet supporting surface 61a.

[0054] The bending portion 63 serves to connect the second supporting portion 62 in an upwardly bent state with respect to the first supporting portion 61. That is, the first supporting portion 61 includes an area from a downstream end portion of the second sheet supporting surface 61a to the bending portion 63 in the sheet feeding direction Df. Further, the second supporting portion 62 includes an area from the bending portion 63 to an uppermost end 62b serving as an example of an uppermost portion positioned at an uppermost position of the third sheet supporting surface 62a. The end portion 62c is formed to extend from the uppermost end 62b downward below a virtual surface having extended the third sheet supporting surface 62a. The extension unit 60 will be described in detail later. That is, the second supporting portion 62 includes the uppermost end 62b between the end portion 62c and a downstream end in the sheet feeding direction Df.

[0055] In the present embodiment, the extension unit 60 is described as being attached to the manual sheet feed unit 50 and constituting a portion of the image forming apparatus 1. However, the present technique is not limited to this example, and the extension unit 60 may be treated as an optional device that is not included in the image forming apparatus 1. In the present embodiment, the state illustrated in FIG. 1 in which the extension unit 60 is attached to the manual sheet feed unit 50 is referred to as an attached state. Further, the state in which the extension unit 60 is detached from the manual sheet feed unit 50 is referred to as a detached state.Image Forming Unit

[0056] The image forming unit 201B forms an image on the sheet S having been fed from a cassette sheet feed unit 230 or the manual sheet feed unit 50 and conveyed by the registration roller pair 13. The image forming unit 201B includes four process cartridges PY, PM, PC, and PK that form toner images of four colors, which are yellow (Y), magenta (M), cyan (C), and black (K), an exposure unit 30, and an intermediate transfer belt 36. The four process cartridges PY, PM, PC, and PK have the same configurations, except that the colors of the formed images differ. Therefore, the configuration and image forming process of only the process cartridge PY is described, and the descriptions of process cartridges PM, PC, and PK are omitted. Further, the image forming unit 201B includes a secondary transfer portion 38 disposed above the process cartridges PY, PM, PC, and PK, and a fixing portion 201E. The toner cartridges 35 supply toner to the developing rollers 34.

[0057] The process cartridge PY includes a photosensitive drum 32 serving as a drum-type electrophotographic photosensitive member, a charge roller 33, and the developing roller 34. The photosensitive drum 32 is supported rotatably by the image forming apparatus 1, and driven to rotate by a driving unit not shown. The photosensitive drum 32 is composed by disposing a photoconductive layer such as an organic optical semiconductor (OPC) on an outer circumference surface of an aluminum cylinder. The charge roller 33 charges the photosensitive drum 32. The charge roller 33 is composed of a core metal and an elastic member having conductivity disposed on the circumference thereof, the charge roller 33 being rotated by coming into contact with the surface of the photosensitive drum 32 and having a charge bias applied thereto from a power supply not shown. The developing roller 34 causes toner of different colors (yellow, magenta, cyan, and black) from each of the process cartridges PY, PM, PC, and PK to be attached to the surface of each photosensitive drum 32. The developing roller 34 causes toner to be attached to an electrostatic latent image on the surface of the photosensitive drum 32 to develop the electrostatic latent image to form a toner image on the surface of the photosensitive drum 32.

[0058] The exposure unit 30 accommodates a laser light source that emits laser light into the casing, and various optical members that conduct the laser light emitted from the laser light source to the corresponding photosensitive drum 32 to perform deflection scanning. The exposure unit 30 irradiates the laser light based on image information to the surface of the charged photosensitive drum 32 to form an electrostatic latent image.

[0059] The secondary transfer portion 38 includes the intermediate transfer belt 36 wound around a driving roller 36a and a tension roller 36b. A primary transfer roller 39 that comes into contact with the intermediate transfer belt 36 is disposed on the inner side of the intermediate transfer belt 36 at a position facing the photosensitive drum 32. The intermediate transfer belt 36 rotates in an arrow direction by the driving roller 36a driven by a driving portion not shown. A secondary transfer roller 37 that transfers a color image formed on the intermediate transfer belt 36 to the sheet S is disposed at a position facing the driving roller 36a of the secondary transfer portion 38.

[0060] The fixing portion 201E is arranged above the secondary transfer roller 37, and above the fixing portion 201E are disposed a first sheet discharge roller pair 225a, a second sheet discharge roller pair 225b, and a reverse portion 201F. The reverse portion 201F is an example of a reconveyance portion, which reverses the sides of the sheet S on which an image has been formed by the image forming unit 201B and conveys the sheet S to the second pre-registration roller pair 12. The reverse portion 201F includes a reverse conveyance roller pair 222 that may be rotated in normal and reverse directions, and a reconveyance path 224 that conveys the sheet S on which an image has been formed on a first side again to the image forming unit 201B. An operation portion 23 through which an operation by a user is received is disposed on an upper portion of the image forming apparatus 1. A touch panel system having both a display function and an input function is adopted as the operation portion 23. The operation portion 23 is connected to the control unit 20 and receives various operations that the user performs through various buttons, such as various information regarding the sheet that the user uses for printing, including sheet type information, sheet grammage information, and sheet size information, and instructions to execute printing or discontinue printing (refer to FIG. 2).Control System

[0061] Next, the control unit 20 and a control system of the image forming apparatus 1 are described with reference to FIG. 2. As illustrated in FIG. 2, the control unit 20 includes various function units, such as a central processing unit (CPU) 21, a memory 22, an image forming control unit 25, a sheet conveyance control unit 26, and a sensor control unit 27. The CPU 21 realizes various processes that the image forming apparatus 1 performs by executing predetermined control programs. The memory 22 is, for example, a random access memory (RAM) or a read only memory (ROM), which store various programs and various data in predetermined storage areas.

[0062] The image forming control unit 25 outputs an instruction to the image forming unit 201B including the exposure unit 30, and controls image formation. The sheet conveyance control unit 26 outputs instructions to a first pre-registration motor 101, a second pre-registration motor 102, and a registration motor 103, controls the drive of various conveyance rollers, and conveys the conveyance of the sheet S. The sensor control unit 27 controls starting or stopping of detection by a sheet presence sensor 104, and receives detection results of various sensors. The operation portion 23 is connected to the control unit 20. Further, the operation portion 23 may also be configured to receives various information regarding the sheet used for printing via the host device 24, such as a personal computer, an image scanner, or a facsimile, connected via a network.Image Forming Operation

[0063] Next, an image forming operation of the image forming apparatus 1 will be described. At first, when the image forming apparatus 1 receives image data of the document to be printed, the image information is subjected to image processing, then converted into electric signals, and transmitted to the exposure unit 30 of the image forming unit 201B. In the image forming unit 201B, the surface of the photosensitive drum 32 charged uniformly to a predetermined polarity and potential by the charge roller 33 is sequentially exposed by laser. Thereby, electrostatic latent images of yellow, magenta, cyan, and black are sequentially formed on the photosensitive drums 32 of the respective process cartridges PY, PM, PC, and PK.

[0064] Thereafter, the electrostatic latent images are developed and visualized by the toners of respective colors, and the toner images of respective colors on the respective photosensitive drums 32 are sequentially superposed and transferred onto the intermediate transfer belt 36 by a primary transfer bias applied to the primary transfer roller 39. Thereby, toner images are formed on the intermediate transfer belt 36.

[0065] In parallel with the toner image forming operation, the sheet S is fed one by one by the cassette sheet feed units 9A and 9B or the manual sheet feed unit 50. The sheet S fed from the cassette sheet feed units 9A and 9B is passed through the first pre-registration roller pair 11 and conveyed to the registration roller pair 13. Skewing of the sheet S is corrected by the first pre-registration roller pair 11 and the registration roller pair 13. Specifically, the leading edge of the sheet S being conveyed is abutted against the nip portion of the registration roller pair 13 being stopped. The first pre-registration roller pair 11 conveys the sheet S further to form a loop so as to perform skew correction. Similarly, the sheet S being fed from the manual sheet feed unit 50 is passed through the second pre-registration roller pair 12 and conveyed to the registration roller pair 13. Skewing of the sheet S is corrected by the second pre-registration roller pair 12 and the registration roller pair 13. In the present embodiment, a skew feed correcting portion 10 includes the first pre-registration roller pair 11, the second pre-registration roller pair 12, and the registration roller pair 13.

[0066] The registration roller pair 13 conveys the sheet S to the secondary transfer portion 38 at a timing at which the toner image on the intermediate transfer belt 36 is transferred to the sheet S. In the secondary transfer portion 38, the toner image is collectively transferred to the sheet S by a secondary transfer bias applied to the secondary transfer roller 37.

[0067] Next, the sheet S to which the toner image has been transferred is conveyed to the fixing portion 201E, and heat and pressure is applied thereto at a roller nip portion formed of a pressure roller 220a and a heating roller 220b, by which the toners of respective colors are melted and mixed, and fixed as a color image onto the sheet S. The sheet S to which the image is fixed is discharged to the discharge space V by a first sheet discharge roller pair 225a or a second sheet discharge roller pair 225b disposed downstream of the fixing portion 201E, and supported on a sheet discharge tray 223 protruded at a bottom side of the discharge space V.

[0068] Meanwhile, when forming images on both sides of the sheet S, the reverse conveyance roller pair 222 is temporarily stopped in a state where the trailing edge of the sheet S is left remaining for a predetermined distance, and thereafter, the reverse conveyance roller pair 222 is rotated in a reverse direction, such that the sheet S is passed through the second pre-registration roller pair 12 via the reconveyance path 224. Then, the sheet S is conveyed again to the registration roller pair 13 and subjected to skew correction, before forming and fixing an image on a second side of the sheet S at the image forming unit 201B.Manual Sheet Feed Portion

[0069] Next, the manual sheet feed unit 50 of the manual sheet feed portion 40 will be described with reference to FIG. 3. FIG. 3 is a perspective view of the manual sheet feed unit 50 and the feeding portion 41. As illustrated in FIG. 3, a leading edge regulating portion 515 that regulates a leading edge position of sheets S in the sheet feeding direction Df is disposed on the manual feed tray 51. The leading edge regulating portion 515 is arranged downstream of the first sheet supporting surface 52 in the sheet feeding direction Df, and is movable to a contact position and an allowing position. The contact position is a position at which the leading edge regulating portion 515 is in contact with a downstream edge of the sheet S supported on the first sheet supporting surface 52 in the sheet feeding direction Df. The allowing position is a position at which the leading edge regulating portion 515 is retracted from the contact position to allow the feeding of the sheet S supported on the first sheet supporting surface 52. The leading edge regulating portion 515 is positioned at the contact position when sheets are not fed, and is positioned at the allowing position when sheets are fed.

[0070] When a start button of the operation portion 23 of the image forming apparatus 1 is pushed, feeding of the sheet S is started. The uppermost sheet S supported on the manual feed tray 51 is fed by rotation of the pickup roller 42 to the separation roller pair 43 including a feed roller and a retard roller. A leading edge of the sheet S separated one by one by the separation roller pair 43 is detected by a leading edge detection sensor 505. The sheet S is sent to the registration roller pair 13 by the second pre-registration roller pair 12 (refer to FIG. 1). The operation thereafter is similar to sheet feeding from cassettes.Outline of Extension Unit

[0071] A sheet storage portion referred to as a sheet feed cassette is disposed in an image forming apparatus, such as a printer, a copying machine, a facsimile, or a multifunction printer. Sheets for printing are accommodated in the sheet storage portion. Generally, one or a plurality of sheet storage portions are provided in an interior of a large-size image forming apparatus. This type of sheet storage portion is designed to accommodate so-called regular size printing sheets, such as an A-size, a B-size, and a letter size. Meanwhile, an image forming apparatus equipped with a manual feed tray on which non-regular size sheets may be placed to correspond to demands for printing images on non-regular size sheets is disclosed. The user can feed sheets from the manual feed tray to the image forming unit of the image forming apparatus.

[0072] In general, a maximum size sheet among the regular size sheets is 13 in. × 19 in., and in the present embodiment, a regular size sheet SN having a regular size is set as a longest regular size sheet having a longest sheet length in the sheet feeding direction Df among the various types of regular size sheets. In the manual sheet feed portion 40, there may be a case where the long sheet SL having a long size, such as approximately 483 mm or more, that is longer than the regular size sheet SN, is fed. In order to feed the long sheet SL from the manual sheet feed portion 40, as illustrated in FIG. 1, an attachment referred to as the extension unit 60 is attached to the manual feed tray 51. By attaching the extension unit 60, the sheet supporting surface of the manual feed tray 51 can be expanded, such that the long sheet SL can be supported, and the long sheet SL having a length as long as 1300 mm can be fed.

[0073] Now, for example, in the configuration of an attachment that extends the manual feed tray disclosed in Japanese Patent Application Laid-Open Publication No. 2015-134688, when attaching the attachment to the manual feed tray, the attachment is attached so as to enclose the manual feed tray from the outer side, such that the size in the sheet width direction of the entire manual feed tray after attachment is increased in size. Therefore, downsizing of the entire manual feed tray after attachment was desired. Therefore, according to the present embodiment, the manual feed tray is downsized in the sheet width direction even in a case where the extension unit 60 is attached to the manual feed tray 51.

[0074] Next, the extension unit 60 of the manual sheet feed portion 40 is described with reference to FIGS. 4 to 5B. FIG. 4 is a perspective view of the extension unit 60 of the manual sheet feed portion 40, and FIGS. 5A and 5B are each a perspective view of attaching the extension unit 60 to the manual sheet feed unit 50. The extension unit 60 includes the first supporting portion 61, the second supporting portion 62 for supporting the long sheet SL, the bending portion 63, and an attachment portion 64. The attachment portion 64 can be detachably attached to an attached portion 54 disposed on the manual feed tray 51, and by attaching the attachment portion 64, the extension unit 60 is attached to the manual sheet feed unit 50, and the long sheet SL having a long length as long as 1300 mm can be supported. According to the present embodiment, the extension unit 60 is narrower than the manual sheet feed unit 50 in the sheet width direction W and longer than the manual sheet feed unit 50 in the sheet feeding direction Df. The configurations of the attachment portion 64 and the attached portion 54 are described later.

[0075] In the present embodiment, the first sheet supporting surface 52 comes into contact with and supports the sheet S, and the second sheet supporting surface 61a comes into contact with and supports the sheet S. The second sheet supporting surface 61a is coplanar with the first sheet supporting surface 52 (refer to FIG. 1). Thereby, the sheet S supported on the first sheet supporting surface 52 and the second sheet supporting surface 61a can be supported in a flat manner, such that occurrence of feeding failures, such as multiple feeding or no feeding, can be suppressed.

[0076] In the present embodiment, the second supporting portion 62 and the bending portion 63 are formed of a wire 65 made of metal, which is one example of a linear member having a U shape. The end portions of the wire 65 are positioned on a downstream side thereof in the sheet feeding direction Df and attached to the first supporting portion 61. The wire 65 is attachable to and detachable from the first supporting portion 61. The bending portion 63 is formed by bending a portion of the wire 65, and it is disposed such that the second supporting portion 62 is bent upward from and continuously with the first supporting portion 61. The bending portion 63 is arranged such that when the regular size sheet SN is supported on the first sheet supporting surface 52 and the second sheet supporting surface 61a (refer to FIGS. 7A and 7B), it is positioned further upstream from an upstream edge of the regular size sheet SN in a sheet feeding direction DF. Further, the bending portion 63 is disposed lower than the second sheet supporting surface 61a. Thereby, the upstream edge of the regular size sheet SN in the sheet feeding direction DF will not come into contact with the second supporting portion 62, and the regular size sheet SN is supported flatly, such that the occurrence of feeding failures, such as multiple feeding and no feeding, can be suppressed. The third sheet supporting surface 62a is a virtual surface having connected the side surfaces of the wire 65 disposed on the sheet supporting side.

[0077] In the present embodiment, the extension unit 60 is formed to have a narrow width in the sheet width direction W than a sheet width of a regular size sheet with a maximum width, which has a maximum sheet width in the sheet width direction W among the various types of regular size sheets. Therefore, there will be no area in the apparatus where the sheet S is not supported in the sheet width direction W when supporting the regular size sheet having a maximum width, such that the increase in size of the apparatus can be suppressed while a frictional resistance is reduced with respect to a sheet surface when feeding the sheet.Long Sheet

[0078] FIGS. 6A and 6B are a perspective view and a side view of a case where the long sheet SL having a length of 1300 mm in the sheet feeding direction Df is supported on the manual sheet feed unit 50 to which the extension unit 60 is attached. A position of an end portion of the long sheet SL is regulated by coming into contact with the leading edge regulating portion 515 disposed on the manual feed tray 51. The long sheet SL is supported on the sheet supporting surface formed of the first sheet supporting surface 52 of the manual feed tray 51, the second sheet supporting surface 61a of the first supporting portion 61, and the third sheet supporting surface 62a of the second supporting portion 62. The bending portion 63 is disposed at a connecting portion between the first supporting portion 61 and the second supporting portion 62, such that an upstream side of the second supporting portion 62 in the conveyance direction extends upward, and the long sheet SL is supported on the extension unit 60 in a manner curved along the bending portion 63. Thereby, the manual sheet feed portion 40 can be downsized compared to a case where the long sheet SL is supported in a flat manner.

[0079] Now, a distance in the sheet feeding direction Df between the leading edge regulating portion 515 positioned at the contact position and the bending portion 63 is referred to as a third distance L3, and a distance from the bending portion 63 to the uppermost end 62b of the second supporting portion 62 is referred to as a fourth distance L4. In this state, a relationship of the third distance L3> the fourth distance L4 is satisfied. Thereby, the area of the long sheet SL supported in a flat manner can be increased, such that the sheet can be supported stably.

[0080] Further, there may be a case where the sheet length of the sheet S in the sheet feeding direction DF supported by the first sheet supporting surface 52, the second sheet supporting surface 61a, and the third sheet supporting surface 62a is longer than a total of the third distance L3 and the fourth distance L4. In this case, as illustrated in FIG. 6B, a portion of the sheet S upstream in the sheet feeding direction Df than a portion supported by the third sheet supporting surface 62a of the sheet S is supported in a state hung downward from the uppermost end 62b of the second supporting portion 62. Thereby, even in a case where the sheet length is longer than a total of the third distance L3 and the fourth distance L4, the sheet can be supported on the manual sheet feed portion 40. Further, according to the present embodiment, the end portion 62c of the wire 65 is formed to extend from the uppermost end 62b downward than the virtual surface having extended the third sheet supporting surface 62a, such that the end portion 62c will not interfere with the sheet S positioned beyond the uppermost end 62b, and a smooth feeding of the sheet can be realized.Regular Size Sheet

[0081] FIGS. 7A and 7B are a perspective view and a side view of a case where the regular size sheet SN having a regular size whose length in the sheet feeding direction Df is longest is supported on the manual sheet feed unit 50 to which the extension unit 60 is attached. A position of an end portion of the regular size sheet SN is regulated by coming into contact with the leading edge regulating portion 515 disposed on the manual feed tray 51. A length in the sheet feeding direction Df between the leading edge regulating portion 515 positioned at the contact position and the bending portion 63 disposed on the second supporting portion 62 of the extension unit 60, that is, the upstream end of the first supporting portion 61, is referred to as a first distance L1. Further, a length of the regular size sheet SN in the sheet feeding direction DF is referred to as a second distance L2.

[0082] In this state, the relationship of the first distance L1> the second distance L2 is satisfied. That is, in a state where the regular size sheet SN is supported by the first sheet supporting surface 52 and the second sheet supporting surface 61a, the first supporting portion 61 has a length in the sheet feeding direction Df extending further upstream from an upstream end of the regular size sheet SN. Thereby, the upstream edge of the regular size sheet SN in the sheet feeding direction DF will not be in contact with the second supporting portion 62 and will be supported in a flat manner, such that the occurrence of feeding failures, such as multiple feeding or no feeding, can be suppressed. That is, even if the regular size sheet SN is supported in a state where the extension unit 60 is attached, the sheet S will not be curved along the bending portion 63 and can be fed in a flat position. In the present embodiment, the regular size sheet having a longest sheet length in the sheet feeding direction Df has a size of 12 in. × 18 in. Therefore, the second distance L2 is set to 457.2 mm, whereas the first distance L1 is set to approximately 470 mm.Details of Extension Unit

[0083] A detailed configuration of the extension unit 60 will be described below with reference to FIGS. 8 to 10B. FIG. 8 is an exploded perspective view illustrating the configuration of the extension unit 60. The first supporting portion 61 of the extension unit 60 includes hooks 702 for attaching to the manual feed tray 51, hook urging members 703 for urging the hooks 702, and a cover portion 704 that accommodates the hooks 702 and the hook urging members 703. Further, the second supporting portion 62 for supporting the long sheet SL is detachably attached to the first supporting portion 61, and by attaching the second supporting portion 62, the long sheet SL having a length as long as 1300 mm can be supported.

[0084] FIG. 9A is an exploded perspective view illustrating the attachment portion 64 from below, FIG. 9B is a perspective view illustrating the attachment portion 64 from below, and FIGS. 10A and 10B are an exploded perspective views illustrating a state where the wire 65 is detached from the first supporting portion 61. As illustrated in FIGS. 9A and 9B, the attachment portion 64 includes the hooks 702, hook pivot shafts 706, the hook urging members 703, and a tray insertion portion 721. The tray insertion portion 721 is an example of an insertion portion, and the extension unit 60 is attached to the manual sheet feed unit 50 by inserting the tray insertion portion 721 to the attached portion 54. According to the present embodiment, the tray insertion portion 721 is narrower than the first sheet supporting surface 52 in the sheet width direction W. Therefore, it is possible to suppress the risk of damaging the exterior of the manual sheet feed unit 50 when attaching and detaching the extension unit 60. According further to the present embodiment, the first supporting portion 61 is narrower than the first sheet supporting surface 52 in the sheet width direction W. Therefore, it is further possible to effectively suppress the risk of damaging the exterior of the manual sheet feed unit 50 when attaching and detaching the extension unit 60. According further to the present embodiment, the second supporting portion 62 and the bending portion 63 are narrower than the first sheet supporting surface 52 in the sheet width direction W.

[0085] Two hook pivot shafts 706 are arranged in a symmetrical arrangement with respect to the sheet width direction W on a rear surface of the second sheet supporting surface 61a of the first supporting portion 61. Hook engagement portions 707 are formed on upper end portions of each of the hook pivot shafts 706. The hooks 702 are attached to the respective hook pivot shafts 706. The hooks 702 include hook pivot axis holes 708, and are attached so as to fit the hook pivot axis holes 708 to the hook pivot shafts 706. The hook engagement portions 707 are formed to be locked in a direction of disengaging the hooks 702, such that the hooks 702 are attached pivotably to the hook pivot shafts 706 so as not to be disengaged to the upper direction.

[0086] The hook urging members 703 are formed of compression coil springs. Urging member positioning portions 709a that are engaged with and that position the hook urging members 703 to prevent the hook urging members 703 from being displaced unnecessarily are disposed on the hooks 702. Further, urging member positioning portions 709b that are engaged with and that position the hook urging members 703 are disposed on a surface of the hooks 702 facing the urging member positioning portions 709a in the sheet width direction W, i.e., rear surface of the second sheet supporting surface 61a. By attaching the hook urging members 703 between opposing urging member positioning portions 709a and 709b so that they are urged away from each other, the hooks 702 are in a constantly urged state by the hook urging members 703. The hook urging members 703 are an example of urging members, and urges the hooks 702 toward the closed position.

[0087] Next, a configuration of the second supporting portion 62 and the attachment of the cover portion 704 will be described. As illustrated in FIGS. 10A and 10B, the cover portion 704 and the wire 65 are attached to a unit in which the first supporting portion 61, the hooks 702, and the hook urging members 703 (refer to FIG. 9A) are assembled. The cover portion 704 is assembled to the first supporting portion 61 and shaped so as not to interfere with the movement of the hooks 702 and the hook urging members 703, and it is formed to completely cover the hook urging members 703 such that the user cannot touch the hook urging members 703 from the exterior. The fixing of the first supporting portion 61 and the cover portion 704 is performed by screw engagement according to the present embodiment, but the present technique is not limited thereto, and for example, engagement through engagement pawls can be adopted.

[0088] The wire 65 is formed of a U-shaped linear member whose downstream side in the sheet feeding direction Df is attached to the first supporting portion 61. End portions 65a of the wire 65 are bent mutually inward in the sheet width direction W. The first supporting portion 61 has two supporting holes 710 opened outward at both ends thereof in the sheet width direction W.

[0089] The respective end portions 65a are positioned by being inserted to the supporting hole 710 and nipped from up-down directions by a wire supporting base 711 and a wire pressing pawl 712 formed on the first supporting portion 61. Further, in order to prevent the second supporting portions 62 from being displaced in the sheet width direction W, wire positioning walls 713 are formed on the first supporting portion 61, such that the second supporting portions 62 are positioned by being nipped also in the sheet width direction W. That is, the wire positioning walls 713 are an example of a retaining portion, and are arranged on outer sides of the respective supporting holes 710 in the sheet width direction. The two end portions 65a of the wire 65 are inserted to the respective supporting holes 710 from an outer side in the sheet width direction W, and further retained and fixed by the wire positioning walls 713 to the outer side in the sheet width direction W. As described, the second supporting portions 62 are configured to be positioned stably both in the up-down direction and the sheet width direction W when conveying the long sheet SL.

[0090] Next, the operation of the hooks 702 will be described with reference to FIGS. 11 and 12. FIG. 11 is a plan view illustrating the hooks 702 in a closed position, and FIG. 12 is a plan view illustrating the hooks 702 in the opened position. The hooks 702 are disposed pivotably with respect to the first supporting portion 61 about the hook pivot shafts 706 serving as a pivot axis. The hooks 702 include outer stopper portions 714 and inner stopper portions 715. The outer stopper portions 714 are disposed to abut against side wall portions of the first supporting portion 61, and the inner stopper portions 715 are disposed to abut against stopper walls 716 disposed on the cover portion 704. The pivotable angle of the hooks 702 is the angle that the hooks 702 pivot to reach a position where the outer stopper portions 714 and the inner stopper portions 715 are abutted, and in the present embodiment, it is set to approximately 20°.

[0091] According to the present embodiment, a state in which the outer stopper portions 714 are abutted against side wall portions of the first supporting portion 61 is referred to as a closed position, as illustrated in FIG. 11, and a state in which the inner stopper portions 715 are abutted against the stopper walls 716 disposed on the cover portion 704 is referred to as an opened position, as illustrated in FIG. 12. That is, the hooks 702 are an example of an engagement member, and are displaceable between an engaged position, i.e., closed position, and a retracting position, i.e., opened position, retracted from the engaged position, i.e., closed position.

[0092] The hooks 702 include switch portions 717 disposed at positions accessible by the users. As illustrated in FIG. 11, in a state where the user is not pressing the switch portions 717, the outer stopper portions 714 are positioned at the closed position abutted against the side wall portions of the first supporting portion 61 by the urging force of the hook urging members 703. As illustrated in FIG. 12, when the user presses the switch portions 717 against the hook urging members 703, the hooks 702 pivot to the opened position where the inner stopper portions 715 abut against the stopper walls 716. That is, the switch portions 717 are one example of an operation portion, and operates the hooks 702 to move toward the opened position. When the user releases the switch portions 717 in this state, the hooks 702 pivot in the opposite direction by the urging force of the hook urging members 703 and return to the closed position.

[0093] The urging force of the hook urging members 703 is set such that it is strong enough to prevent the extension unit 60 from being easily detached but not too strong so that the operability of the user is not deteriorated, and in the present embodiment, it is set, for example, to 500 gf each, i.e., 1000 gf in total. Of course, the urging force is not limited to the above example.Attachment and Detachment of Configuration of Extension Unit

[0094] Next, details related to attachment and detachment of the extension unit 60 to and from the manual sheet feed unit 50 will be described with reference to FIGS. 13A to 19. FIG. 13A is a perspective view illustrating the manual sheet feed unit 50 from an upstream side in the sheet feeding direction Df, that is, from the extension unit 60 side, FIG. 13B is a plan view, and FIG. 13C is a cross-sectional view. The attached portion 54 to which the attachment portion 64 of the extension unit 60 can be detachably attached is disposed on the manual sheet feed unit 50. That is, the attached portion 54 is an example of an insertion port, and it is disposed on an upstream end in the sheet feeding direction Df. The attached portion 54 can be positioned at any position as long as it is disposed between the side regulating plates 53 in the sheet width direction W, and in the present embodiment, it is positioned at a center portion in the sheet width direction W. Thereby, the stability of the long sheet SL supported on the extension unit 60 can be ensured. Guide rails 719 that regulate the position of the extension unit 60 in the sheet width direction W and hook engagement walls 720 which are an example of engaged portions for engaging the hooks 702 are disposed downstream of the attached portion 54 in the sheet feeding direction Df. It may be that the hook engagement walls 720 are arranged on the outer sides of the guide rails 719 in the sheet width direction W so as not to interfere with the attachment and detachment of the extension unit 60.

[0095] Further, as illustrated in FIG. 13C, a gap in the up-down direction is disposed between the tray insertion portion 721 and the cover portion 704 disposed below the tray insertion portion 721 at a leading edge of the attachment portion 64. When attaching the attachment portion 64 to the attached portion 54, a bottom plate portion 51a of the attached portion 54 is inserted to the gap between the tray insertion portion 721 and the cover portion 704. Thereby, the attachment portion 64 and the attached portion 54 can be positioned in the up-down direction. That is, the bottom plate portion 51a is an example of a lower portion member, disposed below the attached portion 54 defining a lower portion of the attached portion 54, and also forming a lower surface of the manual sheet feed unit 50. Further, the cover portion 704 is an example of a lower supporting portion, and in a case where the tray insertion portion 721 is inserted to the attached portion 54, the cover portion 704 sandwiches the bottom plate portion 51a with the tray insertion portion 721 below the tray insertion portion 721. In the present embodiment, the cover portion 704 is narrower than the first sheet supporting surface 52 in the sheet width direction W.

[0096] FIGS. 14 to 16 are each a plan view of a state where the extension unit 60 is attached to the manual sheet feed unit 50. As illustrated in FIG. 14, the first supporting portion 61 includes the tray insertion portion 721. By inserting the tray insertion portion 721 to the attached portion 54 of the manual feed tray 51, the extension unit 60 is attached to the manual sheet feed unit 50.

[0097] As illustrated in FIG. 14, when attaching the extension unit 60 to the manual sheet feed unit 50, at first, the position of the tray insertion portion 721 of the extension unit 60 is set to correspond to the guide rails 719. By having the insertion direction of the tray insertion portion 721 regulated by the guide rails 719, the extension unit 60 is inserted in a straight manner to the manual sheet feed unit 50. When insertion advances, as illustrated in FIG. 15, the hooks 702 come into contact with the hook engagement walls 720. That is, the guide rails 719 are an example of a guide portion, and the manual sheet feed unit 50 guides the tray insertion portion 721 in the interior of the attached portion 54. The guide rails 719 come into contact with and guide the inserted tray insertion portion 721 in an inserted state from both sides in the sheet width direction W, and position the tray insertion portion 721 in the sheet width direction W.

[0098] If the hook engagement walls 720 and the hooks 702 are disposed in parallel in the sheet width direction W, the hooks 702 will abut against the hook engagement walls 720 and will be locked, such that further insertion cannot be performed. Therefore, according to the present embodiment, hook inclination portions 722 are disposed on a leading edge side in an inserting direction of pawl portions of the hooks 702. When the extension unit 60 is pushed in, the hooks 702 pivot along the inclination of the hook inclination portions 722, and as illustrated in FIG. 16, in a state where the pawl portions of the hooks 702 ride over the hook engagement walls 720, the hooks 702 pivot in the opposite direction by the hook urging members 703 and are positioned at the opened position. Thereby, lock surfaces 723 that face the opposite direction as the inserting direction disposed on the pawl portions of the hooks 702 come into contact with the hook engagement walls 720, by which the hooks 702 are returned to the closed position, and the extension unit 60 will be in a state attached to the manual feed tray 51. That is, in a state where the extension unit 60 is attached to the manual sheet feed unit 50, the hooks 702 are positioned at the closed position and engaged with the hook engagement walls 720, such that the extension unit 60 is regulated from being detached from the manual sheet feed unit 50.

[0099] FIGS. 17 to 19 are each a plan view of a state in which the extension unit 60 is detached from the manual sheet feed unit 50. As illustrated in FIG. 17, in a state where the extension unit 60 is attached to the manual sheet feed unit 50, when the user presses the switch portions 717 of the hooks 702, the hooks 702 are pivoted and positioned at the opened position in a direction where the lock surfaces 723 are separated from the hook engagement walls 720. While maintaining this state, as illustrated in FIG. 18, the extension unit 60 is drawn out in a detaching direction from the manual feed tray 51. That is, by having the hooks 702 position at the opened position, the engagement with the hook engagement walls 720 is released, and the extension unit 60 is allowed to be detached from the manual sheet feed unit 50.

[0100] As illustrated in FIG. 19, in a state where the extension unit 60 is completely detached from the manual feed tray 51 and pressing of the switch portions 717 is stopped, the hooks 702 are pivoted in the opposite direction by the hook urging members 703. Thereby, the outer stopper portions 714 of the hooks 702 abut against the side wall portions of the first supporting portion 61 and the hooks 702 are returned to the closed position. According to the configuration described above, the extension unit 60 can be attached to and detached from the manual sheet feed unit 50.

[0101] According to the present embodiment, as illustrated in FIG. 5B, a maximum width in which the side regulating plates 53 of the manual sheet feed unit 50 operate in the sheet width direction W is referred to as a fifth distance L5, and a maximum width of the sheet supporting portion of the extension unit 60 is referred to as a sixth distance L6. In this state, the fifth distance L5 and the sixth distance L6 satisfy a relationship of the fifth distance L5> the sixth distance L6. Specifically, the fifth distance L5 is approximately 320 mm, and the sixth distance L6 is approximately 150 mm. Thereby, a contact area of the manual sheet feed unit 50 and the extension unit 60 may be made small, such that the risk of damaging the exterior of the manual sheet feed unit 50 when attaching and detaching the extension unit 60 may be suppressed.

[0102] Further, in the sheet feeding direction Df, a length of the first sheet supporting surface 52 of the manual feed tray 51 is referred to as a seventh distance L7, and a total length of the sheet supporting portion of the extension unit 60 is referred to as an eighth distance L8. In this state, the seventh distance L7 and the eighth distance L8 satisfy a relationship of the seventh distance L7< the eighth distance L8. Specifically, the seventh distance L7 is approximately 280 mm, and the eighth distance L8 is approximately 590 mm. According to this configuration, in a state where the long sheet SL as illustrated in FIG. 6A is supported, the long sheet SL having a maximum sheet width of 320 mm and sheet length of 1300 mm can be supported and fed.Manual Sheet Feed Unit

[0103] Next, the manual sheet feed unit 50 will be described with reference to FIGS. 20 to 24B. The side regulating plates 53 for regulating the position of the supported sheet S in the sheet width direction W are disposed on the manual sheet feed unit 50, and each includes a sheet regulating surface. FIG. 20 is a perspective view illustrating the manual sheet feed unit 50 prior to supporting the sheet S. The manual sheet feed unit 50 includes two hole portions 5a whose longitudinal direction corresponds to the sheet width direction W. The side regulating plates 53 are connected to rack portions 55 that are passed through the hole portions 5a and arranged movably in the sheet width direction W at a rear surface of the first sheet supporting surface 52.

[0104] FIG. 21 is a perspective view taken from a lower direction, and it is an explanatory view of a vicinity of the rack portions 55 at a rear surface of the manual sheet feed unit 50. A rack gear 516 being engaged with the rack portions 55 of the side regulating plates 53 are rotatably supported on a gear supporting portion 5b disposed on a rear side of the manual sheet feed unit 50, by which the movement of the two side regulating plates 53 are interlocked. A sheet width detection unit 519 is disposed in the vicinity of the rack gear 516. The sheet width detection unit 519 is an example of a second detection unit, and detects a length in the sheet width direction W of the sheet supported on the first sheet supporting surface 52. The sheet width detection unit 519 includes a volume gear 517, and a volume sensor 518. The volume gear 517 is meshed with and rotated in synchronization with the rack gear 516. The volume gear 517 is supported by a shaft portion 518b disposed on the volume sensor 518 supported by the manual sheet feed unit 50.

[0105] When the side regulating plates 53 are operated, the rack gear 516 is rotated via the rack portions 55, and a rotation amount of the shaft portion 518b rotated together with the volume gear 517 that rotates in synchronization with the rack gear 516 is detected by the volume sensor 518. The positional information of the side regulating plates 53 is obtained by having signals transmitted from the volume sensor 518 via a volume sensor bundle wire 518c to the control unit 20. That is, the volume sensor 518 is an example of a second detecting portion, and by detecting the position of the pair of side regulating plates 53, the length in the sheet width direction W of the sheet supported on the first sheet supporting surface 52 is output.

[0106] As illustrated in FIG. 20, the manual sheet feed unit 50 includes a trailing edge detection unit 520. The trailing edge detection unit 520 is an example of a first detection unit, and detects that the length in the sheet feeding direction Df of the sheet S supported on the first sheet supporting surface 52 is longer than a first length L11. The first length L11 is a sheet length of a maximum regular size sheet, for example. As illustrated in FIG. 22, the trailing edge detection unit 520 includes a trailing edge detection flag 521 supported pivotably by the manual sheet feed unit 50, and a trailing edge flag sensor 522. FIG. 23A is a cross-sectional view of the trailing edge detection unit 520 viewed from direction B of FIG. 20 in a state where no sheet is supported, and FIG. 23B is a cross-sectional view of the trailing edge detection unit 520 viewed from direction B of FIG. 20 in a state where a sheet is supported.

[0107] The trailing edge flag sensor 522 is an example of a flag member, which is displaceable to a protruded position protruded above the first sheet supporting surface 52 and to a retracting position below the first sheet supporting surface 52 retracted from the protruded position. As illustrated in FIG. 23A, the trailing edge detection flag 521 supports a flag pivot shaft 521a pivotably by a flag retaining portion 5c of the manual sheet feed unit 50. The trailing edge detection flag 521 includes a weight portion 521w disposed on an opposite side from a sheet contact portion 521c with respect to the flag pivot shaft 521a. In a state illustrated in FIG. 20 in which the sheet S is not supported on the manual sheet feed unit 50, the trailing edge detection flag 521 is configured to rotate in a in a CW direction illustrated in FIG. 22 due to a moment of rotation by the weight of the weight portion 521w. That is, the weight portion 521w is an example of an urging portion, and urges the trailing edge detection flag 521 toward the protruded position.

[0108] In a state illustrated in FIG. 23A where the sheet S is not supported, the position of the trailing edge detection flag 521 is maintained by having a contact portion 521b of the trailing edge detection flag 521 come into contact with a flag contact portion 5d of the manual sheet feed unit 50, wherein this state is referred to as a protruded position. In the state positioned at the protruded position, the sheet contact portion 521c of the trailing edge detection flag 521 is passed through a flag hole 5e formed on the manual sheet feed unit 50 and protrudes above the first sheet supporting surface 52.

[0109] The trailing edge flag sensor 522 for detecting a detection portion 521d of the trailing edge detection flag 521 is retained near the trailing edge detection flag 521 by the manual sheet feed unit 50. The trailing edge flag sensor 522 is configured to detect the position of the trailing edge detection flag 521 by detecting blockage or transmission of light by the detection portion 521d of the trailing edge detection flag 521. For example, in a state illustrated in FIG. 23A where the sheet S is not supported, the trailing edge flag sensor 522 is in a light transmission state.

[0110] As illustrated in FIG. 23B, in a state where the sheet S is supported on the first sheet supporting surface 52, the sheet contact portion 521c of the trailing edge detection flag 521 is pushed down by the sheet S, such that the trailing edge detection flag 521 rotates. Thereby, the detection portion 521d will be in a state blocking the trailing edge flag sensor 522. By transmitting the detection signal of the trailing edge flag sensor 522 via a bundle wire not shown to the control unit 20, the presence or absence of the sheet S can be determined based on the trailing edge detection flag 521. The trailing edge flag sensor 522 is an example of a first detecting portion, and outputs a detection result of whether a sheet length of the sheet supported on the first sheet supporting surface 52 is longer than the first length L11, based on whether the trailing edge detection flag 521 is positioned at the protruded position or at the retracting position.

[0111] FIGS. 24A and 24B are each a view illustrating the manual sheet feed portion 40 from an arrow C direction of FIG. 20, respectively illustrating a case where an A4 size sheet or a case where an A3 size sheet is supported on the first sheet supporting surface 52. A distance from where the leading edge regulating portion 515 regulates the leading edge of the sheet to the sheet contact portion 521c of the trailing edge detection flag 521 (L_SNS) illustrated in FIG. 24A is set to 220 mm. Therefore, as illustrated in FIG. 24A, in a state where an A4 size sheet S is supported, the trailing edge detection flag 521 remains at the protruded position, whereas based on the positional information of the side regulating plates 53, the sheet width is recognized to be 297.0 mm. Based on this combination, the control unit 20 estimates that the regular size of the supported sheet S is A4.

[0112] In a state where the A3 size sheet S is placed as illustrated in FIG. 24B, the sheet length in the sheet feeding direction Df is longer than the distance from the position where the leading edge regulating portion 515 regulates the leading edge of the sheet to the sheet contact portion 521c of the trailing edge detection flag 521 (L_SNS). Therefore, as illustrated in FIG. 23B, the supported sheet S pushes down the trailing edge detection flag 521, and the trailing edge flag sensor 522 will be in a shielded state by the detection portion 521d. Meanwhile, based on the positional information of the side regulating plates 53, it is recognized that the sheet width is 297.0 mm. Based on this combination, the control unit 20 estimates that the regular size of the supported sheet is A3. That is, the control unit 20 determines whether sheet feeding is possible based on the information of the detection result of the trailing edge detection unit 520 and the set sheet length in the sheet feeding direction DF of the sheet supported on the first sheet supporting surface 52, and controls the feeding operation by the feeding portion 41. Further, the control unit 20 determines whether sheet feeding is possible based on the information of the detection result of the sheet width detection unit 519 and the set sheet width in the sheet width direction W of the sheet supported on the first sheet supporting surface 52, and controls the feeding operation by the feeding portion 41.Feeding Operation of Regular Size Sheet

[0113] A processing procedure for executing feeding of the sheet S using the manual sheet feed portion 40 will be described below with reference to the flowchart of FIG. 25. FIG. 25 illustrates a processing procedure of a regular size sheet from when a print job from the manual sheet feed portion 40 is entered to the control unit 20 until a conveyance operation is started, which is hereinafter also referred to as a regular size processing. The user enters a size information of the sheet S being used, hereinafter referred to as a “set size”, based on a setting regarding the print job sent from the host device 24 or based on a setting entered through an input operation using the operation portion 23 of the apparatus (S100). The control unit 20 executes a sheet size detection upon receiving a print job conveyed from the manual sheet feed portion 40 or an input operation (S101). The control unit 20 receives the detection result from various sensors, estimates the sheet size, and detects the same as a detected size.

[0114] The control unit 20 determines whether the sheet widths of the set size and the detected size are the same, i.e., coincide (S102). The control unit 20 performs the determination based on whether the position information of the side regulating plates 53 obtained by the manual sheet feed unit 50 and the width information of the set size coincide. If it is determined that the sheet widths of the set size and the detected size coincide (S102: YES), the control unit 20 determines whether the trailing edge flag sensor 522 is at a protruded position (S103). If it is determined that the trailing edge flag sensor 522 is at the protruded position (S103; YES), the control unit 20 determines whether the length, i.e., sheet length, of the set size in the sheet feeding direction Df is less than 220.0 mm (S104). If it is determined that the sheet length of the set size is less than 220.0 mm (S104; YES), the control unit 20 starts the feeding operation assuming that the set size and the detected size coincide (S105).

[0115] If it is determined in S103 that the trailing edge flag sensor 522 is not at the protruded position (S103; NO), the control unit 20 determines whether the sheet length of the set size is 220.0 mm or more (S106). If it is determined that the sheet length of the set size is 220.0 mm or more (S106; YES), the control unit 20 starts the feeding operation assuming that the set size and the detected size coincide (S105).

[0116] If it is determined in S102 that the sheet widths of the set size and the detected size do not coincide (S102; NO), the control unit 20 determines that the sheet sizes differ, i.e., do not coincide, and notifies a warning that the sheet sizes do not coincide to the operation portion 23 (S107). Similarly, if it is determined in S104 that the sheet length of the set size is not less than 220.0 mm (S104; NO), the control unit 20 determines that the sheet sizes do not coincide, and notifies a warning that the sheet sizes do not coincide to the operation portion 23 (S107). Similarly, if it is determined in S106 that the sheet length of the set size is not equal to or greater than 220.0 mm (S106; NO), the control unit 20 determines that the sheet sizes do not coincide, and notifies a warning that the sheet sizes do not coincide to the operation portion 23 (S107).

[0117] In the present embodiment, the operation portion 23 is one example of a warning output portion, and outputs a warning by display or sound. In the present embodiment, the operation portion 23 is one example of a display portion, and can display a warning regarding the sheet length. Further, to output a warning notice, or to display a warning, from the operation portion 23 is an example of a noncoincidence processing performed by the control unit 20. The warning output portion is not limited to the operation portion 23, and for example, it may be an interface when outputting information to the host device 24 or other devices.Feeding Operation of a Non-Regular Size Sheet

[0118] In the image forming apparatus 1 according to the present embodiment, a maximum regular size that can be placed on the manual sheet feed unit 50 is set to A3 size (sheet length of 420.0 mm × sheet width of 297.0 mm). The sheet length of a maximum regular size sheet in the sheet feeding direction Df is referred as the first length L11. The first length L11 is the sheet length of a maximum regular size sheet in the present example, but the present technique is not limited thereto, and it can be a sheet length of an arbitrary regular size sheet.

[0119] Meanwhile, an irregular size sheet can be conveyed by having a sheet size that is not a regular size, i.e., irregular size, entered by a print job or through input of a user via the operation portion 23. FIG. 26 illustrates a state in which the sheet S is supported on the manual sheet feed unit 50, and the supported sheet S is an irregular size sheet having a sheet length of 600.0 mm × sheet width of 297.0 mm. The sheet S has its leading edge supported by the leading edge regulating portion 515 of the manual sheet feed unit 50, and the trailing edge of the sheet S is not supported since it is greater than the manual sheet feed unit 50, such that it is hung down from the most upstream position in the conveyance direction. In this state, the sheet S having a low stiffness may be in a state curved greatly upward on the manual sheet feed unit 50. In this case, the sheet S is curved and does not come into contact with the sheet contact portion 521c of the trailing edge detection flag 521, such that the trailing edge detection flag 521 stays in the protruded position.

[0120] Next, a processing procedure including the possibility of feeding the long sheet SL using the manual sheet feed portion 40 will be described with reference to the flowchart of FIG. 27. FIG. 27 illustrates a processing procedure from when a print job from the manual sheet feed portion 40 is entered to the control unit 20 until the conveyance operation is started. In the present description, a case where the extension unit 60 is not used is described, but for example, a similar processing may be executed in a case where the extension unit 60 is used to feed the long sheet SL having a sheet length of 900 mm or 1200 mm. In that case, the extension unit 60 supports the sheet S having a sheet length longer than the first length L11 together with the first sheet supporting surface 52. That is, in a state attached to the manual sheet feed unit 50, the extension unit 60 includes the third sheet supporting surface 62a serving as an example of an upper sheet supporting portion that supports the long sheet SL above the first sheet supporting surface 52.

[0121] The user enters a size information, i.e., set size, of the sheet S to be used via a setting through a print job sent from the host device 24 or via a setting entered through an input operation using the operation portion 23 of the apparatus (S200). The control unit 20 determines whether the sheet length of the set size is longer than a sheet length, for example, 450.0 mm, allowed as the maximum regular size (S201).

[0122] If it is determined that the sheet length of the set size is longer than the sheet length allowed as the maximum regular size (S201; YES), the control unit 20 starts a feeding operation (S202). That is, if the sheet length of the set size is longer than the sheet length allowed as the maximum regular size, as illustrated in FIG. 26, the sheet S may be curved upward such that the trailing edge detection flag 521 is maintained at the protruded position, and in consideration of such a case, feeding is started regardless of the position of the trailing edge detection flag 521. Meanwhile, if it is determined that the sheet length of the set size is not longer than the sheet length allowed as the maximum regular size (S201; NO), the control unit 20 advances to a regular size processing illustrated in FIG. 25 (S203).

[0123] That is, the control unit 20 can execute a noncoincidence processing in a case where the detection result of the trailing edge detection unit 520 and a set sheet length of the sheet according to an entered sheet information corresponding to the manual sheet feed unit 50 do not coincide. In a case where the set sheet length is shorter than the first length L11, i.e., sheet length of a maximum regular size, and where the detection result of the trailing edge detection unit 520 and the set sheet length coincide, the control unit 20 will not execute the noncoincidence processing. In this case, the feeding operation is started without displaying a warning on the operation portion 23. In a case where the set sheet length is shorter than the first length L11 and the detection result of the trailing edge detection unit 520 does not coincide with the set sheet length, the control unit 20 executes a noncoincidence processing. Further, in a case where the set sheet length is longer than the first length L11, the control unit 20 will not execute the noncoincidence processing. Thereby, even in a case where the sheet length of the set size is longer than the sheet length allowed as the maximum regular size, an erroneous warning notice can be prevented from being output.

[0124] As described above, according to the manual sheet feed portion 40 of the present embodiment, the extension unit 60 is narrower than the manual sheet feed unit 50 in the sheet width direction W, and longer than the manual sheet feed unit 50 in the sheet feeding direction Df. Therefore, the size of the manual sheet feed portion 40 in the sheet width direction W after attaching the extension unit 60 can be reduced. Further, the tray insertion portion 721 is narrower than the manual sheet feed unit 50 in the sheet width direction W. Therefore, it becomes possible to attach the extension unit 60 while reducing the contact area between the manual sheet feed unit 50 and the extension unit 60 and suppressing the influence on the exterior of the manual sheet feed unit 50. Therefore, the extension unit 60 capable of being attached and detached while suppressing the occurrence of damages on the decorative surface can be realized.

[0125] According to the present disclosure, the apparatus may be downsized in the sheet width direction.Other Embodiments

[0126] The present embodiment was described based on a case where the trailing edge detection flag 521 is disposed at one location, but the present technique is not limited thereto, and a plurality of detection flags can be disposed. According further to the present embodiment, an example of a case where the operation is changed if the size information designated by the user is longer than the length allowed as the maximum regular size, as illustrated in FIG. 27, but the present technique is not limited thereto. For example, it may be possible to set a function to selectively switch between the operation illustrated in FIG. 25 and the operation illustrated in FIG. 27, and to provide this function selectively by having a service technician change the settings of the apparatus, for example.

[0127] According to the embodiment described above, as illustrated in FIG. 27, after setting the set size, the control unit 20 determines whether the sheet length of the set size is longer than a sheet length of 450.0 mm, for example, that is allowed as the maximum regular size (S201). However, the present technique is not limited thereto, and for example, it may be possible to determine whether the sheet widths of the set size and the detected size coincide prior to the processing of S201. The processing procedure of such a case is illustrated in FIG. 28. A case where the extension unit 60 is not used is illustrated, but a similar processing may be executed in a case where the extension unit 60 is used.

[0128] FIG. 28 illustrates a processing procedure from a state where a print job from the manual sheet feed portion 40 is entered to the control unit 20 until the conveyance operation is started. The user enters a size information, i.e., set size, of the sheet S to be used via a setting entered through a print job sent from the host device 24 or via a setting entered through an input operation using the operation portion 23 of the apparatus (S300). The control unit 20 receives the print job conveyed from the manual sheet feed portion 40 or based on the input operation, and executes the sheet size detection (S301). The control unit 20 receives the detection results from various sensors, estimates the sheet size, and detects the same as a detected size.

[0129] The control unit 20 determines whether the sheet widths of the set size and the detected size coincide (S302). In this case, the control unit 20 performs the determination based on whether the positional information of the side regulating plates 53 obtained by the manual sheet feed unit 50 and the width information of the set size coincide. If it is determined that the sheet widths of the set size and the detected size coincide (S302; YES), the control unit 20 executes S201 to S203 illustrated in FIG. 27. If it is determined that the sheet widths of the set size and the detected size do not coincide (S302; NO), the control unit 20 determines that the sheet sizes do not coincide, and notifies a warning that the sizes do not coincide to the operation portion 23 (S303).

[0130] That is, the control unit 20 can execute the noncoincidence processing in a case where the detection result of the sheet width detection unit 519 and the set sheet width of the sheet based on the entered sheet information corresponding to the manual sheet feed unit 50 do not coincide. The control unit 20 executes the noncoincidence processing in a case where the detection result of the sheet width detection unit 519 and the set sheet width do not coincide. The control unit 20 does not execute the noncoincidence processing in a case where the detection result of the sheet width detection unit 519 and the set sheet width coincide, where the set sheet length is shorter than the first length L11, and where the detection result of the trailing edge detection unit 520 and the set sheet length coincide. Further, the control unit 20 executes the noncoincidence processing in a case where the detection result of the sheet width detection unit 519 and the set sheet width coincide, where the set sheet length is shorter than the first length L11, and where the detection result of the trailing edge detection unit 520 and the set sheet length do not coincide. Further, the control unit 20 does not execute the noncoincidence processing in a case where the detection result of the sheet width detection unit 519 and the set sheet width coincide, and where the set sheet length is longer than the first length L11.

[0131] According to the present processing procedure, whether the sheet widths coincide is determined before determining whether the sheet is a long sheet in S201, and a warning is notified if the sheet widths do not coincide. Therefore, rapid processing can be realized compared to a case where whether the sheet widths coincide is determined in a regular size processing after determining that the regular size sheet is not a long sheet.

[0132] While the present disclosure has been described with reference to embodiments, it is to be understood that the present disclosure is not limited to the disclosed embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

[0133] This application claims the benefit of Japanese Patent Application No. 2025-028754, filed February 26, 2025 which is hereby incorporated by reference herein in its entirety.

Examples

Embodiment Construction

[0046]An image forming apparatus 1 according to the present embodiment will be described below with reference to FIGS. 1 to 28. At first, a schematic configuration of the image forming apparatus 1 according to the present embodiment will be described with reference to FIG. 1. FIG. 1 is a cross-sectional view illustrating a schematic configuration of the image forming apparatus 1 according to the present embodiment taken from a front side. The image forming apparatus 1 is a tandem-type, intermediate transfer-type laser beam printer adopting an electrophotographic process. The image forming apparatus 1 can form and output a full-color or mono-color image corresponding to a print image data output from a host device 24 (refer to FIG. 2) connected to a control unit 20 on a sheet S serving as a recording medium.

Image Forming Apparatus

[0047]The image forming apparatus 1 includes an apparatus body 201A, and an image forming unit 201B for forming an image on the sheet S. An image reading ap...

BACKGROUNDField of the Technology

[0001] The present disclosure relates to a sheet feeding apparatus for feeding sheets, an image forming apparatus equipped with the sheet feeding apparatus, and an extension supporting unit adopted in the sheet feeding apparatus.Description of the Related Art

[0002] Japanese Patent Application Laid-Open Publication No. 2015-134688 discloses an image forming apparatus equipped with a manual feed tray on which sheets can be placed. Users can feed sheets through the manual feed tray to an image forming unit of the image forming apparatus. In this image forming apparatus, there may be a case where a sheet having a sheet length size that exceeds a sheet size that can be placed flatly on the manual feed tray in a sheet feed direction, for example, approximately longer than 450 mm, hereinafter referred to as a long sheet, is placed on the manual feed tray. In order to allow such a long sheet to be placed on the manual feed tray, a configuration is disclosed where an attachment corresponding to a long sheet is attached for placing a long sheet on a manual feed tray in a manner enclosing the manual feed tray from an outer side.

[0003] However, according to the configuration disclosed in Japanese Patent Application Laid-Open Publication No. 2015-134688, when attaching the attachment to the manual feed tray, the attachment is attached in a manner enclosing the manual feed tray from the outer side, such that the size in a sheet width direction of the entire manual feed tray after attachment is increased.SUMMARY

[0004] The present disclosure provides a sheet feeding apparatus, an image forming apparatus, and an extension supporting unit that are downsized in the sheet width direction.

[0005] According to a first aspect of the present disclosure, a sheet feeding apparatus includes a first sheet supporting unit including a first sheet supporting surface configured to support a sheet, a feeding portion configured to feed the sheet supported on the first sheet supporting surface in a sheet feeding direction, a second sheet supporting unit detachably attached to the first sheet supporting unit, and including a second sheet supporting surface configured to support a sheet and positioned upstream of the first sheet supporting surface in the sheet feeding direction in an attached state attached to the first sheet supporting unit. The second sheet supporting surface is narrower than the first sheet supporting surface in a width direction orthogonal to the sheet feeding direction, and longer than the first sheet supporting surface in the sheet feeding direction.

[0006] According to a second aspect of the present disclosure, an image forming apparatus includes the sheet feeding apparatus, and an image forming unit configured to form an image on a sheet.

[0007] According to a third aspect of the present disclosure, an extension supporting unit detachably attached to a sheet supporting unit including a first sheet supporting surface configured to support a sheet includes a second sheet supporting surface configured to support a sheet and positioned upstream of the sheet supporting surface in a sheet feeding direction by a feeding portion in an attached state attached to the sheet supporting unit. The second sheet supporting surface is narrower than the first sheet supporting surface in a width direction orthogonal to the sheet feeding direction, and longer than the first sheet supporting surface in the sheet feeding direction.

[0008] Features of the present disclosure will become apparent from the following description of embodiments with reference to the attached drawings. The following description of embodiments is described by way of example.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a cross-sectional view illustrating an image forming apparatus according to an embodiment.

[0010] FIG. 2 is a block diagram illustrating a control system of the image forming apparatus according to the embodiment.

[0011] FIG. 3 is a perspective view illustrating a feeding portion according to the embodiment.

[0012] FIG. 4 is a perspective view illustrating an extension unit according to the embodiment.

[0013] FIG. 5A is a perspective view of a state prior to attachment of a manual sheet feed unit and an extension unit according to the embodiment.

[0014] FIG. 5B is a perspective view of a state after attachment of the manual sheet feed unit and the extension unit according to the embodiment.

[0015] FIG. 6A is a perspective view of a state in which a long sheet is supported on the manual sheet feed unit having the extension unit according to the embodiment attached thereto.

[0016] FIG. 6B is a front view of a state in which a long sheet is supported on the manual sheet feed unit having the extension unit according to the embodiment attached thereto.

[0017] FIG. 7A is a perspective view of a state in which a regular size sheet is supported on the manual sheet feed unit having the extension unit according to the embodiment attached thereto.

[0018] FIG. 7B is a front view of a state in which a regular size sheet is supported on the manual sheet feed unit having the extension unit according to the embodiment attached thereto.

[0019] FIG. 8 is an exploded perspective view illustrating the extension unit according to the embodiment.

[0020] FIG. 9A is an exploded perspective view illustrating an attachment portion of the extension unit according to the embodiment.

[0021] FIG. 9B is a perspective view illustrating the attachment portion of the extension unit according to the embodiment.

[0022] FIG. 10A is an exploded perspective view illustrating the extension unit according to the embodiment.

[0023] FIG. 10B is a detail view illustrating the extension unit according to the embodiment.

[0024] FIG. 11 is a plan view illustrating a state in which hooks are at a closed position in the attachment portion of the extension unit according to the embodiment.

[0025] FIG. 12 is a plan view illustrating a state in which the hooks are at an opened position in the attachment portion of the extension unit according to the embodiment.

[0026] FIG. 13A is a perspective view illustrating an attached portion of the manual sheet feed unit according to the embodiment.

[0027] FIG. 13B is a plan view illustrating the attached portion of the manual sheet feed unit according to the embodiment.

[0028] FIG. 13C is a cross-sectional view illustrating the attached portion of the manual sheet feed unit according to the embodiment.

[0029] FIG. 14 is a plan view illustrating a state prior to having the hooks come into contact with hook engagement walls when attaching the attachment portion of the extension unit to the attached portion of the manual sheet feed unit according to the embodiment.

[0030] FIG. 15 is a plan view illustrating a state in which the hooks are in contact with the hook engagement walls and pivoted when attaching the attachment portion of the extension unit to the attached portion of the manual sheet feed unit according to the embodiment.

[0031] FIG. 16 is a plan view illustrating a state in which the attachment portion of the extension unit is attached to the attached portion of the manual sheet feed unit according to the embodiment.

[0032] FIG. 17 is a plan view illustrating a state in which the hooks are opened when detaching the attachment portion of the extension unit from the attached portion of the manual sheet feed unit according to the embodiment.

[0033] FIG. 18 is a plan view illustrating a state in which the hooks are disengaged from the hook engagement walls when detaching the attachment portion of the extension unit from the attached portion of the manual sheet feed unit according to the embodiment.

[0034] FIG. 19 is a plan view illustrating a state in which the attachment portion of the extension unit is detached from the attached portion of the manual sheet feed unit according to the embodiment.

[0035] FIG. 20 is a perspective view of the manual sheet feed unit according to the embodiment.

[0036] FIG. 21 is a perspective view in which a rack and pinion mechanism for moving a side regulating plate of the manual sheet feed unit according to the embodiment is viewed from a lower side.

[0037] FIG. 22 is a perspective view illustrating a trailing edge detection unit of the manual sheet feed unit according to the embodiment.

[0038] FIG. 23A is a cross-sectional view illustrating a trailing edge detection flag of the manual sheet feed unit according to the embodiment, wherein the trailing edge detection flag is positioned at a protruded position.

[0039] FIG. 23B is a cross-sectional view illustrating the trailing edge detection flag of the manual sheet feed unit according to the embodiment, wherein the trailing edge detection flag is positioned at a retracting position.

[0040] FIG. 24A is a cross-sectional view illustrating the trailing edge detection flag of the manual sheet feed unit according to the embodiment, wherein an A4 size sheet is supported.

[0041] FIG. 24B is a cross-sectional view illustrating the trailing edge detection flag of the manual sheet feed unit according to the embodiment, wherein an A3 size sheet is supported.

[0042] FIG. 25 is a flowchart illustrating a procedure for feeding sheets using the manual sheet feed portion according to the embodiment.

[0043] FIG. 26 is a cross-sectional view illustrating a state of the trailing edge detection flag in a state where a long sheet is supported on the manual sheet feed unit according to the embodiment.

[0044] FIG. 27 is a flowchart illustrating a procedure for feeding a long sheet using the manual sheet feed portion according to the embodiment.

[0045] FIG. 28 is a flowchart illustrating a procedure for feeding a long sheet using the manual sheet feed portion according to the embodiment, wherein a sheet width is also determined.DESCRIPTION OF THE EMBODIMENTS

[0046] An image forming apparatus 1 according to the present embodiment will be described below with reference to FIGS. 1 to 28. At first, a schematic configuration of the image forming apparatus 1 according to the present embodiment will be described with reference to FIG. 1. FIG. 1 is a cross-sectional view illustrating a schematic configuration of the image forming apparatus 1 according to the present embodiment taken from a front side. The image forming apparatus 1 is a tandem-type, intermediate transfer-type laser beam printer adopting an electrophotographic process. The image forming apparatus 1 can form and output a full-color or mono-color image corresponding to a print image data output from a host device 24 (refer to FIG. 2) connected to a control unit 20 on a sheet S serving as a recording medium.Image Forming Apparatus

[0047] The image forming apparatus 1 includes an apparatus body 201A, and an image forming unit 201B for forming an image on the sheet S. An image reading apparatus 202 arranged approximately parallelly is disposed above the apparatus body 201A. A discharge space V for discharging sheets is formed between the image reading apparatus 202 and the apparatus body 201A.Sheet Feed Unit

[0048] The sheets S are stored in sheet feed cassettes 7A and 7B of cassette sheet feed units 9A and 9B according to size, or supported on a manual sheet feed portion 40.

[0049] The cassette sheet feed units 9A and 9B include the sheet feed cassettes 7A and 7B that store the sheets S and feeding portions 6A and 6B that feed the sheets S from the sheet feed cassettes 7A and 7B. The cassette sheet feed units 9A and 9B store different size sheets S, but the configurations of the respective feeding portions 6A and 6B are similar, such that the feeding portion 6A will be described below. The feeding portion 6A includes a pickup roller 2, and a separation roller pair 5 composed of a feed roller and a retard roller for separating the sheet S delivered from the pickup roller 2. The sheet S separated one by one by the separation roller pair 5 is conveyed by a first pre-registration roller pair 11 to a registration roller pair 13.

[0050] The manual sheet feed portion 40 is an example of a sheet feeding apparatus, and includes a manual sheet feed unit 50, a feeding portion 41, and an extension unit 60. According to the present embodiment, in the manual sheet feed unit 50, a direction in which the supported sheets S are fed is referred to as a sheet feeding direction Df, and a direction orthogonal to the sheet feeding direction Df, that is, a width direction of the supported sheet S is referred to as a sheet width direction W.

[0051] The manual sheet feed unit 50 is an example of a first sheet supporting unit and a sheet supporting unit, and includes a manual feed tray 51, and a first sheet supporting surface 52 formed on an upper surface of the manual feed tray 51 and supporting the sheet S. The manual sheet feed unit 50 is openable and closable by pivoting with respect to the apparatus body 201A, and it is displaceable in a closed position and an opened position. The manual feed tray 51 supports the sheet S stacked on the first sheet supporting surface 52 in the opened state. Further, the manual feed tray 51 includes a pair of side regulating plates 53 that are disposed movably in the sheet width direction W on the manual sheet feed unit 50 and that regulate the position of a sheet supported on the first sheet supporting surface 52 by coming into contact with end portions of the sheet in the sheet width direction W. An air blow fan unit not shown for separating the sheets may be disposed on the side regulating plates 53.

[0052] FIG. 3 is a perspective view illustrating the manual sheet feed unit 50 and the feeding portion 41 according to the present embodiment. As illustrated in FIG. 3, the feeding portion 41 feeds the sheet S supported on the first sheet supporting surface 52 of the manual feed tray 51 to a second pre-registration roller pair 12. The feeding portion 41 includes a pickup roller 42, and a separation roller pair 43 composed of a feed roller and a retard roller for separating the sheet S delivered from the pickup roller 42. The sheet S separated one by one by the separation roller pair 43 is conveyed by the second pre-registration roller pair 12 to the registration roller pair 13. That is, the feeding portion 41 feeds the sheet S supported on the first sheet supporting surface 52 to the sheet feeding direction Df.

[0053] As illustrated in FIG. 1, the extension unit 60 is an example of a second sheet supporting unit and an extension supporting unit, and is detachably attached to the manual sheet feed unit 50 in a direction along the sheet feeding direction Df. In an attached state attached to the manual sheet feed unit 50, the extension unit 60 is positioned upstream of the manual feed tray 51 in the sheet feeding direction Df and supports the sheet S. The extension unit 60 includes a first supporting portion 61, a second supporting portion 62, a bending portion 63, and an end portion 62c, which is a most upstream end in a sheet feeding direction Df. The first supporting portion 61 includes a second sheet supporting surface 61a that is extended upstream in the sheet feeding direction Df from the first sheet supporting surface 52. The second supporting portion 62 includes a third sheet supporting surface 62a that is arranged upstream of the second sheet supporting surface 61a in the sheet feeding direction Df and that supports a long sheet SL together with the first sheet supporting surface 52 and the second sheet supporting surface 61a.

[0054] The bending portion 63 serves to connect the second supporting portion 62 in an upwardly bent state with respect to the first supporting portion 61. That is, the first supporting portion 61 includes an area from a downstream end portion of the second sheet supporting surface 61a to the bending portion 63 in the sheet feeding direction Df. Further, the second supporting portion 62 includes an area from the bending portion 63 to an uppermost end 62b serving as an example of an uppermost portion positioned at an uppermost position of the third sheet supporting surface 62a. The end portion 62c is formed to extend from the uppermost end 62b downward below a virtual surface having extended the third sheet supporting surface 62a. The extension unit 60 will be described in detail later. That is, the second supporting portion 62 includes the uppermost end 62b between the end portion 62c and a downstream end in the sheet feeding direction Df.

[0055] In the present embodiment, the extension unit 60 is described as being attached to the manual sheet feed unit 50 and constituting a portion of the image forming apparatus 1. However, the present technique is not limited to this example, and the extension unit 60 may be treated as an optional device that is not included in the image forming apparatus 1. In the present embodiment, the state illustrated in FIG. 1 in which the extension unit 60 is attached to the manual sheet feed unit 50 is referred to as an attached state. Further, the state in which the extension unit 60 is detached from the manual sheet feed unit 50 is referred to as a detached state.Image Forming Unit

[0056] The image forming unit 201B forms an image on the sheet S having been fed from a cassette sheet feed unit 230 or the manual sheet feed unit 50 and conveyed by the registration roller pair 13. The image forming unit 201B includes four process cartridges PY, PM, PC, and PK that form toner images of four colors, which are yellow (Y), magenta (M), cyan (C), and black (K), an exposure unit 30, and an intermediate transfer belt 36. The four process cartridges PY, PM, PC, and PK have the same configurations, except that the colors of the formed images differ. Therefore, the configuration and image forming process of only the process cartridge PY is described, and the descriptions of process cartridges PM, PC, and PK are omitted. Further, the image forming unit 201B includes a secondary transfer portion 38 disposed above the process cartridges PY, PM, PC, and PK, and a fixing portion 201E. The toner cartridges 35 supply toner to the developing rollers 34.

[0057] The process cartridge PY includes a photosensitive drum 32 serving as a drum-type electrophotographic photosensitive member, a charge roller 33, and the developing roller 34. The photosensitive drum 32 is supported rotatably by the image forming apparatus 1, and driven to rotate by a driving unit not shown. The photosensitive drum 32 is composed by disposing a photoconductive layer such as an organic optical semiconductor (OPC) on an outer circumference surface of an aluminum cylinder. The charge roller 33 charges the photosensitive drum 32. The charge roller 33 is composed of a core metal and an elastic member having conductivity disposed on the circumference thereof, the charge roller 33 being rotated by coming into contact with the surface of the photosensitive drum 32 and having a charge bias applied thereto from a power supply not shown. The developing roller 34 causes toner of different colors (yellow, magenta, cyan, and black) from each of the process cartridges PY, PM, PC, and PK to be attached to the surface of each photosensitive drum 32. The developing roller 34 causes toner to be attached to an electrostatic latent image on the surface of the photosensitive drum 32 to develop the electrostatic latent image to form a toner image on the surface of the photosensitive drum 32.

[0058] The exposure unit 30 accommodates a laser light source that emits laser light into the casing, and various optical members that conduct the laser light emitted from the laser light source to the corresponding photosensitive drum 32 to perform deflection scanning. The exposure unit 30 irradiates the laser light based on image information to the surface of the charged photosensitive drum 32 to form an electrostatic latent image.

[0059] The secondary transfer portion 38 includes the intermediate transfer belt 36 wound around a driving roller 36a and a tension roller 36b. A primary transfer roller 39 that comes into contact with the intermediate transfer belt 36 is disposed on the inner side of the intermediate transfer belt 36 at a position facing the photosensitive drum 32. The intermediate transfer belt 36 rotates in an arrow direction by the driving roller 36a driven by a driving portion not shown. A secondary transfer roller 37 that transfers a color image formed on the intermediate transfer belt 36 to the sheet S is disposed at a position facing the driving roller 36a of the secondary transfer portion 38.

[0060] The fixing portion 201E is arranged above the secondary transfer roller 37, and above the fixing portion 201E are disposed a first sheet discharge roller pair 225a, a second sheet discharge roller pair 225b, and a reverse portion 201F. The reverse portion 201F is an example of a reconveyance portion, which reverses the sides of the sheet S on which an image has been formed by the image forming unit 201B and conveys the sheet S to the second pre-registration roller pair 12. The reverse portion 201F includes a reverse conveyance roller pair 222 that may be rotated in normal and reverse directions, and a reconveyance path 224 that conveys the sheet S on which an image has been formed on a first side again to the image forming unit 201B. An operation portion 23 through which an operation by a user is received is disposed on an upper portion of the image forming apparatus 1. A touch panel system having both a display function and an input function is adopted as the operation portion 23. The operation portion 23 is connected to the control unit 20 and receives various operations that the user performs through various buttons, such as various information regarding the sheet that the user uses for printing, including sheet type information, sheet grammage information, and sheet size information, and instructions to execute printing or discontinue printing (refer to FIG. 2).Control System

[0061] Next, the control unit 20 and a control system of the image forming apparatus 1 are described with reference to FIG. 2. As illustrated in FIG. 2, the control unit 20 includes various function units, such as a central processing unit (CPU) 21, a memory 22, an image forming control unit 25, a sheet conveyance control unit 26, and a sensor control unit 27. The CPU 21 realizes various processes that the image forming apparatus 1 performs by executing predetermined control programs. The memory 22 is, for example, a random access memory (RAM) or a read only memory (ROM), which store various programs and various data in predetermined storage areas.

[0062] The image forming control unit 25 outputs an instruction to the image forming unit 201B including the exposure unit 30, and controls image formation. The sheet conveyance control unit 26 outputs instructions to a first pre-registration motor 101, a second pre-registration motor 102, and a registration motor 103, controls the drive of various conveyance rollers, and conveys the conveyance of the sheet S. The sensor control unit 27 controls starting or stopping of detection by a sheet presence sensor 104, and receives detection results of various sensors. The operation portion 23 is connected to the control unit 20. Further, the operation portion 23 may also be configured to receives various information regarding the sheet used for printing via the host device 24, such as a personal computer, an image scanner, or a facsimile, connected via a network.Image Forming Operation

[0063] Next, an image forming operation of the image forming apparatus 1 will be described. At first, when the image forming apparatus 1 receives image data of the document to be printed, the image information is subjected to image processing, then converted into electric signals, and transmitted to the exposure unit 30 of the image forming unit 201B. In the image forming unit 201B, the surface of the photosensitive drum 32 charged uniformly to a predetermined polarity and potential by the charge roller 33 is sequentially exposed by laser. Thereby, electrostatic latent images of yellow, magenta, cyan, and black are sequentially formed on the photosensitive drums 32 of the respective process cartridges PY, PM, PC, and PK.

[0064] Thereafter, the electrostatic latent images are developed and visualized by the toners of respective colors, and the toner images of respective colors on the respective photosensitive drums 32 are sequentially superposed and transferred onto the intermediate transfer belt 36 by a primary transfer bias applied to the primary transfer roller 39. Thereby, toner images are formed on the intermediate transfer belt 36.

[0065] In parallel with the toner image forming operation, the sheet S is fed one by one by the cassette sheet feed units 9A and 9B or the manual sheet feed unit 50. The sheet S fed from the cassette sheet feed units 9A and 9B is passed through the first pre-registration roller pair 11 and conveyed to the registration roller pair 13. Skewing of the sheet S is corrected by the first pre-registration roller pair 11 and the registration roller pair 13. Specifically, the leading edge of the sheet S being conveyed is abutted against the nip portion of the registration roller pair 13 being stopped. The first pre-registration roller pair 11 conveys the sheet S further to form a loop so as to perform skew correction. Similarly, the sheet S being fed from the manual sheet feed unit 50 is passed through the second pre-registration roller pair 12 and conveyed to the registration roller pair 13. Skewing of the sheet S is corrected by the second pre-registration roller pair 12 and the registration roller pair 13. In the present embodiment, a skew feed correcting portion 10 includes the first pre-registration roller pair 11, the second pre-registration roller pair 12, and the registration roller pair 13.

[0066] The registration roller pair 13 conveys the sheet S to the secondary transfer portion 38 at a timing at which the toner image on the intermediate transfer belt 36 is transferred to the sheet S. In the secondary transfer portion 38, the toner image is collectively transferred to the sheet S by a secondary transfer bias applied to the secondary transfer roller 37.

[0067] Next, the sheet S to which the toner image has been transferred is conveyed to the fixing portion 201E, and heat and pressure is applied thereto at a roller nip portion formed of a pressure roller 220a and a heating roller 220b, by which the toners of respective colors are melted and mixed, and fixed as a color image onto the sheet S. The sheet S to which the image is fixed is discharged to the discharge space V by a first sheet discharge roller pair 225a or a second sheet discharge roller pair 225b disposed downstream of the fixing portion 201E, and supported on a sheet discharge tray 223 protruded at a bottom side of the discharge space V.

[0068] Meanwhile, when forming images on both sides of the sheet S, the reverse conveyance roller pair 222 is temporarily stopped in a state where the trailing edge of the sheet S is left remaining for a predetermined distance, and thereafter, the reverse conveyance roller pair 222 is rotated in a reverse direction, such that the sheet S is passed through the second pre-registration roller pair 12 via the reconveyance path 224. Then, the sheet S is conveyed again to the registration roller pair 13 and subjected to skew correction, before forming and fixing an image on a second side of the sheet S at the image forming unit 201B.Manual Sheet Feed Portion

[0069] Next, the manual sheet feed unit 50 of the manual sheet feed portion 40 will be described with reference to FIG. 3. FIG. 3 is a perspective view of the manual sheet feed unit 50 and the feeding portion 41. As illustrated in FIG. 3, a leading edge regulating portion 515 that regulates a leading edge position of sheets S in the sheet feeding direction Df is disposed on the manual feed tray 51. The leading edge regulating portion 515 is arranged downstream of the first sheet supporting surface 52 in the sheet feeding direction Df, and is movable to a contact position and an allowing position. The contact position is a position at which the leading edge regulating portion 515 is in contact with a downstream edge of the sheet S supported on the first sheet supporting surface 52 in the sheet feeding direction Df. The allowing position is a position at which the leading edge regulating portion 515 is retracted from the contact position to allow the feeding of the sheet S supported on the first sheet supporting surface 52. The leading edge regulating portion 515 is positioned at the contact position when sheets are not fed, and is positioned at the allowing position when sheets are fed.

[0070] When a start button of the operation portion 23 of the image forming apparatus 1 is pushed, feeding of the sheet S is started. The uppermost sheet S supported on the manual feed tray 51 is fed by rotation of the pickup roller 42 to the separation roller pair 43 including a feed roller and a retard roller. A leading edge of the sheet S separated one by one by the separation roller pair 43 is detected by a leading edge detection sensor 505. The sheet S is sent to the registration roller pair 13 by the second pre-registration roller pair 12 (refer to FIG. 1). The operation thereafter is similar to sheet feeding from cassettes.Outline of Extension Unit

[0071] A sheet storage portion referred to as a sheet feed cassette is disposed in an image forming apparatus, such as a printer, a copying machine, a facsimile, or a multifunction printer. Sheets for printing are accommodated in the sheet storage portion. Generally, one or a plurality of sheet storage portions are provided in an interior of a large-size image forming apparatus. This type of sheet storage portion is designed to accommodate so-called regular size printing sheets, such as an A-size, a B-size, and a letter size. Meanwhile, an image forming apparatus equipped with a manual feed tray on which non-regular size sheets may be placed to correspond to demands for printing images on non-regular size sheets is disclosed. The user can feed sheets from the manual feed tray to the image forming unit of the image forming apparatus.

[0072] In general, a maximum size sheet among the regular size sheets is 13 in. × 19 in., and in the present embodiment, a regular size sheet SN having a regular size is set as a longest regular size sheet having a longest sheet length in the sheet feeding direction Df among the various types of regular size sheets. In the manual sheet feed portion 40, there may be a case where the long sheet SL having a long size, such as approximately 483 mm or more, that is longer than the regular size sheet SN, is fed. In order to feed the long sheet SL from the manual sheet feed portion 40, as illustrated in FIG. 1, an attachment referred to as the extension unit 60 is attached to the manual feed tray 51. By attaching the extension unit 60, the sheet supporting surface of the manual feed tray 51 can be expanded, such that the long sheet SL can be supported, and the long sheet SL having a length as long as 1300 mm can be fed.

[0073] Now, for example, in the configuration of an attachment that extends the manual feed tray disclosed in Japanese Patent Application Laid-Open Publication No. 2015-134688, when attaching the attachment to the manual feed tray, the attachment is attached so as to enclose the manual feed tray from the outer side, such that the size in the sheet width direction of the entire manual feed tray after attachment is increased in size. Therefore, downsizing of the entire manual feed tray after attachment was desired. Therefore, according to the present embodiment, the manual feed tray is downsized in the sheet width direction even in a case where the extension unit 60 is attached to the manual feed tray 51.

[0074] Next, the extension unit 60 of the manual sheet feed portion 40 is described with reference to FIGS. 4 to 5B. FIG. 4 is a perspective view of the extension unit 60 of the manual sheet feed portion 40, and FIGS. 5A and 5B are each a perspective view of attaching the extension unit 60 to the manual sheet feed unit 50. The extension unit 60 includes the first supporting portion 61, the second supporting portion 62 for supporting the long sheet SL, the bending portion 63, and an attachment portion 64. The attachment portion 64 can be detachably attached to an attached portion 54 disposed on the manual feed tray 51, and by attaching the attachment portion 64, the extension unit 60 is attached to the manual sheet feed unit 50, and the long sheet SL having a long length as long as 1300 mm can be supported. According to the present embodiment, the extension unit 60 is narrower than the manual sheet feed unit 50 in the sheet width direction W and longer than the manual sheet feed unit 50 in the sheet feeding direction Df. The configurations of the attachment portion 64 and the attached portion 54 are described later.

[0075] In the present embodiment, the first sheet supporting surface 52 comes into contact with and supports the sheet S, and the second sheet supporting surface 61a comes into contact with and supports the sheet S. The second sheet supporting surface 61a is coplanar with the first sheet supporting surface 52 (refer to FIG. 1). Thereby, the sheet S supported on the first sheet supporting surface 52 and the second sheet supporting surface 61a can be supported in a flat manner, such that occurrence of feeding failures, such as multiple feeding or no feeding, can be suppressed.

[0076] In the present embodiment, the second supporting portion 62 and the bending portion 63 are formed of a wire 65 made of metal, which is one example of a linear member having a U shape. The end portions of the wire 65 are positioned on a downstream side thereof in the sheet feeding direction Df and attached to the first supporting portion 61. The wire 65 is attachable to and detachable from the first supporting portion 61. The bending portion 63 is formed by bending a portion of the wire 65, and it is disposed such that the second supporting portion 62 is bent upward from and continuously with the first supporting portion 61. The bending portion 63 is arranged such that when the regular size sheet SN is supported on the first sheet supporting surface 52 and the second sheet supporting surface 61a (refer to FIGS. 7A and 7B), it is positioned further upstream from an upstream edge of the regular size sheet SN in a sheet feeding direction DF. Further, the bending portion 63 is disposed lower than the second sheet supporting surface 61a. Thereby, the upstream edge of the regular size sheet SN in the sheet feeding direction DF will not come into contact with the second supporting portion 62, and the regular size sheet SN is supported flatly, such that the occurrence of feeding failures, such as multiple feeding and no feeding, can be suppressed. The third sheet supporting surface 62a is a virtual surface having connected the side surfaces of the wire 65 disposed on the sheet supporting side.

[0077] In the present embodiment, the extension unit 60 is formed to have a narrow width in the sheet width direction W than a sheet width of a regular size sheet with a maximum width, which has a maximum sheet width in the sheet width direction W among the various types of regular size sheets. Therefore, there will be no area in the apparatus where the sheet S is not supported in the sheet width direction W when supporting the regular size sheet having a maximum width, such that the increase in size of the apparatus can be suppressed while a frictional resistance is reduced with respect to a sheet surface when feeding the sheet.Long Sheet

[0078] FIGS. 6A and 6B are a perspective view and a side view of a case where the long sheet SL having a length of 1300 mm in the sheet feeding direction Df is supported on the manual sheet feed unit 50 to which the extension unit 60 is attached. A position of an end portion of the long sheet SL is regulated by coming into contact with the leading edge regulating portion 515 disposed on the manual feed tray 51. The long sheet SL is supported on the sheet supporting surface formed of the first sheet supporting surface 52 of the manual feed tray 51, the second sheet supporting surface 61a of the first supporting portion 61, and the third sheet supporting surface 62a of the second supporting portion 62. The bending portion 63 is disposed at a connecting portion between the first supporting portion 61 and the second supporting portion 62, such that an upstream side of the second supporting portion 62 in the conveyance direction extends upward, and the long sheet SL is supported on the extension unit 60 in a manner curved along the bending portion 63. Thereby, the manual sheet feed portion 40 can be downsized compared to a case where the long sheet SL is supported in a flat manner.

[0079] Now, a distance in the sheet feeding direction Df between the leading edge regulating portion 515 positioned at the contact position and the bending portion 63 is referred to as a third distance L3, and a distance from the bending portion 63 to the uppermost end 62b of the second supporting portion 62 is referred to as a fourth distance L4. In this state, a relationship of the third distance L3> the fourth distance L4 is satisfied. Thereby, the area of the long sheet SL supported in a flat manner can be increased, such that the sheet can be supported stably.

[0080] Further, there may be a case where the sheet length of the sheet S in the sheet feeding direction DF supported by the first sheet supporting surface 52, the second sheet supporting surface 61a, and the third sheet supporting surface 62a is longer than a total of the third distance L3 and the fourth distance L4. In this case, as illustrated in FIG. 6B, a portion of the sheet S upstream in the sheet feeding direction Df than a portion supported by the third sheet supporting surface 62a of the sheet S is supported in a state hung downward from the uppermost end 62b of the second supporting portion 62. Thereby, even in a case where the sheet length is longer than a total of the third distance L3 and the fourth distance L4, the sheet can be supported on the manual sheet feed portion 40. Further, according to the present embodiment, the end portion 62c of the wire 65 is formed to extend from the uppermost end 62b downward than the virtual surface having extended the third sheet supporting surface 62a, such that the end portion 62c will not interfere with the sheet S positioned beyond the uppermost end 62b, and a smooth feeding of the sheet can be realized.Regular Size Sheet

[0081] FIGS. 7A and 7B are a perspective view and a side view of a case where the regular size sheet SN having a regular size whose length in the sheet feeding direction Df is longest is supported on the manual sheet feed unit 50 to which the extension unit 60 is attached. A position of an end portion of the regular size sheet SN is regulated by coming into contact with the leading edge regulating portion 515 disposed on the manual feed tray 51. A length in the sheet feeding direction Df between the leading edge regulating portion 515 positioned at the contact position and the bending portion 63 disposed on the second supporting portion 62 of the extension unit 60, that is, the upstream end of the first supporting portion 61, is referred to as a first distance L1. Further, a length of the regular size sheet SN in the sheet feeding direction DF is referred to as a second distance L2.

[0082] In this state, the relationship of the first distance L1> the second distance L2 is satisfied. That is, in a state where the regular size sheet SN is supported by the first sheet supporting surface 52 and the second sheet supporting surface 61a, the first supporting portion 61 has a length in the sheet feeding direction Df extending further upstream from an upstream end of the regular size sheet SN. Thereby, the upstream edge of the regular size sheet SN in the sheet feeding direction DF will not be in contact with the second supporting portion 62 and will be supported in a flat manner, such that the occurrence of feeding failures, such as multiple feeding or no feeding, can be suppressed. That is, even if the regular size sheet SN is supported in a state where the extension unit 60 is attached, the sheet S will not be curved along the bending portion 63 and can be fed in a flat position. In the present embodiment, the regular size sheet having a longest sheet length in the sheet feeding direction Df has a size of 12 in. × 18 in. Therefore, the second distance L2 is set to 457.2 mm, whereas the first distance L1 is set to approximately 470 mm.Details of Extension Unit

[0083] A detailed configuration of the extension unit 60 will be described below with reference to FIGS. 8 to 10B. FIG. 8 is an exploded perspective view illustrating the configuration of the extension unit 60. The first supporting portion 61 of the extension unit 60 includes hooks 702 for attaching to the manual feed tray 51, hook urging members 703 for urging the hooks 702, and a cover portion 704 that accommodates the hooks 702 and the hook urging members 703. Further, the second supporting portion 62 for supporting the long sheet SL is detachably attached to the first supporting portion 61, and by attaching the second supporting portion 62, the long sheet SL having a length as long as 1300 mm can be supported.

[0084] FIG. 9A is an exploded perspective view illustrating the attachment portion 64 from below, FIG. 9B is a perspective view illustrating the attachment portion 64 from below, and FIGS. 10A and 10B are an exploded perspective views illustrating a state where the wire 65 is detached from the first supporting portion 61. As illustrated in FIGS. 9A and 9B, the attachment portion 64 includes the hooks 702, hook pivot shafts 706, the hook urging members 703, and a tray insertion portion 721. The tray insertion portion 721 is an example of an insertion portion, and the extension unit 60 is attached to the manual sheet feed unit 50 by inserting the tray insertion portion 721 to the attached portion 54. According to the present embodiment, the tray insertion portion 721 is narrower than the first sheet supporting surface 52 in the sheet width direction W. Therefore, it is possible to suppress the risk of damaging the exterior of the manual sheet feed unit 50 when attaching and detaching the extension unit 60. According further to the present embodiment, the first supporting portion 61 is narrower than the first sheet supporting surface 52 in the sheet width direction W. Therefore, it is further possible to effectively suppress the risk of damaging the exterior of the manual sheet feed unit 50 when attaching and detaching the extension unit 60. According further to the present embodiment, the second supporting portion 62 and the bending portion 63 are narrower than the first sheet supporting surface 52 in the sheet width direction W.

[0085] Two hook pivot shafts 706 are arranged in a symmetrical arrangement with respect to the sheet width direction W on a rear surface of the second sheet supporting surface 61a of the first supporting portion 61. Hook engagement portions 707 are formed on upper end portions of each of the hook pivot shafts 706. The hooks 702 are attached to the respective hook pivot shafts 706. The hooks 702 include hook pivot axis holes 708, and are attached so as to fit the hook pivot axis holes 708 to the hook pivot shafts 706. The hook engagement portions 707 are formed to be locked in a direction of disengaging the hooks 702, such that the hooks 702 are attached pivotably to the hook pivot shafts 706 so as not to be disengaged to the upper direction.

[0086] The hook urging members 703 are formed of compression coil springs. Urging member positioning portions 709a that are engaged with and that position the hook urging members 703 to prevent the hook urging members 703 from being displaced unnecessarily are disposed on the hooks 702. Further, urging member positioning portions 709b that are engaged with and that position the hook urging members 703 are disposed on a surface of the hooks 702 facing the urging member positioning portions 709a in the sheet width direction W, i.e., rear surface of the second sheet supporting surface 61a. By attaching the hook urging members 703 between opposing urging member positioning portions 709a and 709b so that they are urged away from each other, the hooks 702 are in a constantly urged state by the hook urging members 703. The hook urging members 703 are an example of urging members, and urges the hooks 702 toward the closed position.

[0087] Next, a configuration of the second supporting portion 62 and the attachment of the cover portion 704 will be described. As illustrated in FIGS. 10A and 10B, the cover portion 704 and the wire 65 are attached to a unit in which the first supporting portion 61, the hooks 702, and the hook urging members 703 (refer to FIG. 9A) are assembled. The cover portion 704 is assembled to the first supporting portion 61 and shaped so as not to interfere with the movement of the hooks 702 and the hook urging members 703, and it is formed to completely cover the hook urging members 703 such that the user cannot touch the hook urging members 703 from the exterior. The fixing of the first supporting portion 61 and the cover portion 704 is performed by screw engagement according to the present embodiment, but the present technique is not limited thereto, and for example, engagement through engagement pawls can be adopted.

[0088] The wire 65 is formed of a U-shaped linear member whose downstream side in the sheet feeding direction Df is attached to the first supporting portion 61. End portions 65a of the wire 65 are bent mutually inward in the sheet width direction W. The first supporting portion 61 has two supporting holes 710 opened outward at both ends thereof in the sheet width direction W.

[0089] The respective end portions 65a are positioned by being inserted to the supporting hole 710 and nipped from up-down directions by a wire supporting base 711 and a wire pressing pawl 712 formed on the first supporting portion 61. Further, in order to prevent the second supporting portions 62 from being displaced in the sheet width direction W, wire positioning walls 713 are formed on the first supporting portion 61, such that the second supporting portions 62 are positioned by being nipped also in the sheet width direction W. That is, the wire positioning walls 713 are an example of a retaining portion, and are arranged on outer sides of the respective supporting holes 710 in the sheet width direction. The two end portions 65a of the wire 65 are inserted to the respective supporting holes 710 from an outer side in the sheet width direction W, and further retained and fixed by the wire positioning walls 713 to the outer side in the sheet width direction W. As described, the second supporting portions 62 are configured to be positioned stably both in the up-down direction and the sheet width direction W when conveying the long sheet SL.

[0090] Next, the operation of the hooks 702 will be described with reference to FIGS. 11 and 12. FIG. 11 is a plan view illustrating the hooks 702 in a closed position, and FIG. 12 is a plan view illustrating the hooks 702 in the opened position. The hooks 702 are disposed pivotably with respect to the first supporting portion 61 about the hook pivot shafts 706 serving as a pivot axis. The hooks 702 include outer stopper portions 714 and inner stopper portions 715. The outer stopper portions 714 are disposed to abut against side wall portions of the first supporting portion 61, and the inner stopper portions 715 are disposed to abut against stopper walls 716 disposed on the cover portion 704. The pivotable angle of the hooks 702 is the angle that the hooks 702 pivot to reach a position where the outer stopper portions 714 and the inner stopper portions 715 are abutted, and in the present embodiment, it is set to approximately 20°.

[0091] According to the present embodiment, a state in which the outer stopper portions 714 are abutted against side wall portions of the first supporting portion 61 is referred to as a closed position, as illustrated in FIG. 11, and a state in which the inner stopper portions 715 are abutted against the stopper walls 716 disposed on the cover portion 704 is referred to as an opened position, as illustrated in FIG. 12. That is, the hooks 702 are an example of an engagement member, and are displaceable between an engaged position, i.e., closed position, and a retracting position, i.e., opened position, retracted from the engaged position, i.e., closed position.

[0092] The hooks 702 include switch portions 717 disposed at positions accessible by the users. As illustrated in FIG. 11, in a state where the user is not pressing the switch portions 717, the outer stopper portions 714 are positioned at the closed position abutted against the side wall portions of the first supporting portion 61 by the urging force of the hook urging members 703. As illustrated in FIG. 12, when the user presses the switch portions 717 against the hook urging members 703, the hooks 702 pivot to the opened position where the inner stopper portions 715 abut against the stopper walls 716. That is, the switch portions 717 are one example of an operation portion, and operates the hooks 702 to move toward the opened position. When the user releases the switch portions 717 in this state, the hooks 702 pivot in the opposite direction by the urging force of the hook urging members 703 and return to the closed position.

[0093] The urging force of the hook urging members 703 is set such that it is strong enough to prevent the extension unit 60 from being easily detached but not too strong so that the operability of the user is not deteriorated, and in the present embodiment, it is set, for example, to 500 gf each, i.e., 1000 gf in total. Of course, the urging force is not limited to the above example.Attachment and Detachment of Configuration of Extension Unit

[0094] Next, details related to attachment and detachment of the extension unit 60 to and from the manual sheet feed unit 50 will be described with reference to FIGS. 13A to 19. FIG. 13A is a perspective view illustrating the manual sheet feed unit 50 from an upstream side in the sheet feeding direction Df, that is, from the extension unit 60 side, FIG. 13B is a plan view, and FIG. 13C is a cross-sectional view. The attached portion 54 to which the attachment portion 64 of the extension unit 60 can be detachably attached is disposed on the manual sheet feed unit 50. That is, the attached portion 54 is an example of an insertion port, and it is disposed on an upstream end in the sheet feeding direction Df. The attached portion 54 can be positioned at any position as long as it is disposed between the side regulating plates 53 in the sheet width direction W, and in the present embodiment, it is positioned at a center portion in the sheet width direction W. Thereby, the stability of the long sheet SL supported on the extension unit 60 can be ensured. Guide rails 719 that regulate the position of the extension unit 60 in the sheet width direction W and hook engagement walls 720 which are an example of engaged portions for engaging the hooks 702 are disposed downstream of the attached portion 54 in the sheet feeding direction Df. It may be that the hook engagement walls 720 are arranged on the outer sides of the guide rails 719 in the sheet width direction W so as not to interfere with the attachment and detachment of the extension unit 60.

[0095] Further, as illustrated in FIG. 13C, a gap in the up-down direction is disposed between the tray insertion portion 721 and the cover portion 704 disposed below the tray insertion portion 721 at a leading edge of the attachment portion 64. When attaching the attachment portion 64 to the attached portion 54, a bottom plate portion 51a of the attached portion 54 is inserted to the gap between the tray insertion portion 721 and the cover portion 704. Thereby, the attachment portion 64 and the attached portion 54 can be positioned in the up-down direction. That is, the bottom plate portion 51a is an example of a lower portion member, disposed below the attached portion 54 defining a lower portion of the attached portion 54, and also forming a lower surface of the manual sheet feed unit 50. Further, the cover portion 704 is an example of a lower supporting portion, and in a case where the tray insertion portion 721 is inserted to the attached portion 54, the cover portion 704 sandwiches the bottom plate portion 51a with the tray insertion portion 721 below the tray insertion portion 721. In the present embodiment, the cover portion 704 is narrower than the first sheet supporting surface 52 in the sheet width direction W.

[0096] FIGS. 14 to 16 are each a plan view of a state where the extension unit 60 is attached to the manual sheet feed unit 50. As illustrated in FIG. 14, the first supporting portion 61 includes the tray insertion portion 721. By inserting the tray insertion portion 721 to the attached portion 54 of the manual feed tray 51, the extension unit 60 is attached to the manual sheet feed unit 50.

[0097] As illustrated in FIG. 14, when attaching the extension unit 60 to the manual sheet feed unit 50, at first, the position of the tray insertion portion 721 of the extension unit 60 is set to correspond to the guide rails 719. By having the insertion direction of the tray insertion portion 721 regulated by the guide rails 719, the extension unit 60 is inserted in a straight manner to the manual sheet feed unit 50. When insertion advances, as illustrated in FIG. 15, the hooks 702 come into contact with the hook engagement walls 720. That is, the guide rails 719 are an example of a guide portion, and the manual sheet feed unit 50 guides the tray insertion portion 721 in the interior of the attached portion 54. The guide rails 719 come into contact with and guide the inserted tray insertion portion 721 in an inserted state from both sides in the sheet width direction W, and position the tray insertion portion 721 in the sheet width direction W.

[0098] If the hook engagement walls 720 and the hooks 702 are disposed in parallel in the sheet width direction W, the hooks 702 will abut against the hook engagement walls 720 and will be locked, such that further insertion cannot be performed. Therefore, according to the present embodiment, hook inclination portions 722 are disposed on a leading edge side in an inserting direction of pawl portions of the hooks 702. When the extension unit 60 is pushed in, the hooks 702 pivot along the inclination of the hook inclination portions 722, and as illustrated in FIG. 16, in a state where the pawl portions of the hooks 702 ride over the hook engagement walls 720, the hooks 702 pivot in the opposite direction by the hook urging members 703 and are positioned at the opened position. Thereby, lock surfaces 723 that face the opposite direction as the inserting direction disposed on the pawl portions of the hooks 702 come into contact with the hook engagement walls 720, by which the hooks 702 are returned to the closed position, and the extension unit 60 will be in a state attached to the manual feed tray 51. That is, in a state where the extension unit 60 is attached to the manual sheet feed unit 50, the hooks 702 are positioned at the closed position and engaged with the hook engagement walls 720, such that the extension unit 60 is regulated from being detached from the manual sheet feed unit 50.

[0099] FIGS. 17 to 19 are each a plan view of a state in which the extension unit 60 is detached from the manual sheet feed unit 50. As illustrated in FIG. 17, in a state where the extension unit 60 is attached to the manual sheet feed unit 50, when the user presses the switch portions 717 of the hooks 702, the hooks 702 are pivoted and positioned at the opened position in a direction where the lock surfaces 723 are separated from the hook engagement walls 720. While maintaining this state, as illustrated in FIG. 18, the extension unit 60 is drawn out in a detaching direction from the manual feed tray 51. That is, by having the hooks 702 position at the opened position, the engagement with the hook engagement walls 720 is released, and the extension unit 60 is allowed to be detached from the manual sheet feed unit 50.

[0100] As illustrated in FIG. 19, in a state where the extension unit 60 is completely detached from the manual feed tray 51 and pressing of the switch portions 717 is stopped, the hooks 702 are pivoted in the opposite direction by the hook urging members 703. Thereby, the outer stopper portions 714 of the hooks 702 abut against the side wall portions of the first supporting portion 61 and the hooks 702 are returned to the closed position. According to the configuration described above, the extension unit 60 can be attached to and detached from the manual sheet feed unit 50.

[0101] According to the present embodiment, as illustrated in FIG. 5B, a maximum width in which the side regulating plates 53 of the manual sheet feed unit 50 operate in the sheet width direction W is referred to as a fifth distance L5, and a maximum width of the sheet supporting portion of the extension unit 60 is referred to as a sixth distance L6. In this state, the fifth distance L5 and the sixth distance L6 satisfy a relationship of the fifth distance L5> the sixth distance L6. Specifically, the fifth distance L5 is approximately 320 mm, and the sixth distance L6 is approximately 150 mm. Thereby, a contact area of the manual sheet feed unit 50 and the extension unit 60 may be made small, such that the risk of damaging the exterior of the manual sheet feed unit 50 when attaching and detaching the extension unit 60 may be suppressed.

[0102] Further, in the sheet feeding direction Df, a length of the first sheet supporting surface 52 of the manual feed tray 51 is referred to as a seventh distance L7, and a total length of the sheet supporting portion of the extension unit 60 is referred to as an eighth distance L8. In this state, the seventh distance L7 and the eighth distance L8 satisfy a relationship of the seventh distance L7< the eighth distance L8. Specifically, the seventh distance L7 is approximately 280 mm, and the eighth distance L8 is approximately 590 mm. According to this configuration, in a state where the long sheet SL as illustrated in FIG. 6A is supported, the long sheet SL having a maximum sheet width of 320 mm and sheet length of 1300 mm can be supported and fed.Manual Sheet Feed Unit

[0103] Next, the manual sheet feed unit 50 will be described with reference to FIGS. 20 to 24B. The side regulating plates 53 for regulating the position of the supported sheet S in the sheet width direction W are disposed on the manual sheet feed unit 50, and each includes a sheet regulating surface. FIG. 20 is a perspective view illustrating the manual sheet feed unit 50 prior to supporting the sheet S. The manual sheet feed unit 50 includes two hole portions 5a whose longitudinal direction corresponds to the sheet width direction W. The side regulating plates 53 are connected to rack portions 55 that are passed through the hole portions 5a and arranged movably in the sheet width direction W at a rear surface of the first sheet supporting surface 52.

[0104] FIG. 21 is a perspective view taken from a lower direction, and it is an explanatory view of a vicinity of the rack portions 55 at a rear surface of the manual sheet feed unit 50. A rack gear 516 being engaged with the rack portions 55 of the side regulating plates 53 are rotatably supported on a gear supporting portion 5b disposed on a rear side of the manual sheet feed unit 50, by which the movement of the two side regulating plates 53 are interlocked. A sheet width detection unit 519 is disposed in the vicinity of the rack gear 516. The sheet width detection unit 519 is an example of a second detection unit, and detects a length in the sheet width direction W of the sheet supported on the first sheet supporting surface 52. The sheet width detection unit 519 includes a volume gear 517, and a volume sensor 518. The volume gear 517 is meshed with and rotated in synchronization with the rack gear 516. The volume gear 517 is supported by a shaft portion 518b disposed on the volume sensor 518 supported by the manual sheet feed unit 50.

[0105] When the side regulating plates 53 are operated, the rack gear 516 is rotated via the rack portions 55, and a rotation amount of the shaft portion 518b rotated together with the volume gear 517 that rotates in synchronization with the rack gear 516 is detected by the volume sensor 518. The positional information of the side regulating plates 53 is obtained by having signals transmitted from the volume sensor 518 via a volume sensor bundle wire 518c to the control unit 20. That is, the volume sensor 518 is an example of a second detecting portion, and by detecting the position of the pair of side regulating plates 53, the length in the sheet width direction W of the sheet supported on the first sheet supporting surface 52 is output.

[0106] As illustrated in FIG. 20, the manual sheet feed unit 50 includes a trailing edge detection unit 520. The trailing edge detection unit 520 is an example of a first detection unit, and detects that the length in the sheet feeding direction Df of the sheet S supported on the first sheet supporting surface 52 is longer than a first length L11. The first length L11 is a sheet length of a maximum regular size sheet, for example. As illustrated in FIG. 22, the trailing edge detection unit 520 includes a trailing edge detection flag 521 supported pivotably by the manual sheet feed unit 50, and a trailing edge flag sensor 522. FIG. 23A is a cross-sectional view of the trailing edge detection unit 520 viewed from direction B of FIG. 20 in a state where no sheet is supported, and FIG. 23B is a cross-sectional view of the trailing edge detection unit 520 viewed from direction B of FIG. 20 in a state where a sheet is supported.

[0107] The trailing edge flag sensor 522 is an example of a flag member, which is displaceable to a protruded position protruded above the first sheet supporting surface 52 and to a retracting position below the first sheet supporting surface 52 retracted from the protruded position. As illustrated in FIG. 23A, the trailing edge detection flag 521 supports a flag pivot shaft 521a pivotably by a flag retaining portion 5c of the manual sheet feed unit 50. The trailing edge detection flag 521 includes a weight portion 521w disposed on an opposite side from a sheet contact portion 521c with respect to the flag pivot shaft 521a. In a state illustrated in FIG. 20 in which the sheet S is not supported on the manual sheet feed unit 50, the trailing edge detection flag 521 is configured to rotate in a in a CW direction illustrated in FIG. 22 due to a moment of rotation by the weight of the weight portion 521w. That is, the weight portion 521w is an example of an urging portion, and urges the trailing edge detection flag 521 toward the protruded position.

[0108] In a state illustrated in FIG. 23A where the sheet S is not supported, the position of the trailing edge detection flag 521 is maintained by having a contact portion 521b of the trailing edge detection flag 521 come into contact with a flag contact portion 5d of the manual sheet feed unit 50, wherein this state is referred to as a protruded position. In the state positioned at the protruded position, the sheet contact portion 521c of the trailing edge detection flag 521 is passed through a flag hole 5e formed on the manual sheet feed unit 50 and protrudes above the first sheet supporting surface 52.

[0109] The trailing edge flag sensor 522 for detecting a detection portion 521d of the trailing edge detection flag 521 is retained near the trailing edge detection flag 521 by the manual sheet feed unit 50. The trailing edge flag sensor 522 is configured to detect the position of the trailing edge detection flag 521 by detecting blockage or transmission of light by the detection portion 521d of the trailing edge detection flag 521. For example, in a state illustrated in FIG. 23A where the sheet S is not supported, the trailing edge flag sensor 522 is in a light transmission state.

[0110] As illustrated in FIG. 23B, in a state where the sheet S is supported on the first sheet supporting surface 52, the sheet contact portion 521c of the trailing edge detection flag 521 is pushed down by the sheet S, such that the trailing edge detection flag 521 rotates. Thereby, the detection portion 521d will be in a state blocking the trailing edge flag sensor 522. By transmitting the detection signal of the trailing edge flag sensor 522 via a bundle wire not shown to the control unit 20, the presence or absence of the sheet S can be determined based on the trailing edge detection flag 521. The trailing edge flag sensor 522 is an example of a first detecting portion, and outputs a detection result of whether a sheet length of the sheet supported on the first sheet supporting surface 52 is longer than the first length L11, based on whether the trailing edge detection flag 521 is positioned at the protruded position or at the retracting position.

[0111] FIGS. 24A and 24B are each a view illustrating the manual sheet feed portion 40 from an arrow C direction of FIG. 20, respectively illustrating a case where an A4 size sheet or a case where an A3 size sheet is supported on the first sheet supporting surface 52. A distance from where the leading edge regulating portion 515 regulates the leading edge of the sheet to the sheet contact portion 521c of the trailing edge detection flag 521 (L_SNS) illustrated in FIG. 24A is set to 220 mm. Therefore, as illustrated in FIG. 24A, in a state where an A4 size sheet S is supported, the trailing edge detection flag 521 remains at the protruded position, whereas based on the positional information of the side regulating plates 53, the sheet width is recognized to be 297.0 mm. Based on this combination, the control unit 20 estimates that the regular size of the supported sheet S is A4.

[0112] In a state where the A3 size sheet S is placed as illustrated in FIG. 24B, the sheet length in the sheet feeding direction Df is longer than the distance from the position where the leading edge regulating portion 515 regulates the leading edge of the sheet to the sheet contact portion 521c of the trailing edge detection flag 521 (L_SNS). Therefore, as illustrated in FIG. 23B, the supported sheet S pushes down the trailing edge detection flag 521, and the trailing edge flag sensor 522 will be in a shielded state by the detection portion 521d. Meanwhile, based on the positional information of the side regulating plates 53, it is recognized that the sheet width is 297.0 mm. Based on this combination, the control unit 20 estimates that the regular size of the supported sheet is A3. That is, the control unit 20 determines whether sheet feeding is possible based on the information of the detection result of the trailing edge detection unit 520 and the set sheet length in the sheet feeding direction DF of the sheet supported on the first sheet supporting surface 52, and controls the feeding operation by the feeding portion 41. Further, the control unit 20 determines whether sheet feeding is possible based on the information of the detection result of the sheet width detection unit 519 and the set sheet width in the sheet width direction W of the sheet supported on the first sheet supporting surface 52, and controls the feeding operation by the feeding portion 41.Feeding Operation of Regular Size Sheet

[0113] A processing procedure for executing feeding of the sheet S using the manual sheet feed portion 40 will be described below with reference to the flowchart of FIG. 25. FIG. 25 illustrates a processing procedure of a regular size sheet from when a print job from the manual sheet feed portion 40 is entered to the control unit 20 until a conveyance operation is started, which is hereinafter also referred to as a regular size processing. The user enters a size information of the sheet S being used, hereinafter referred to as a “set size”, based on a setting regarding the print job sent from the host device 24 or based on a setting entered through an input operation using the operation portion 23 of the apparatus (S100). The control unit 20 executes a sheet size detection upon receiving a print job conveyed from the manual sheet feed portion 40 or an input operation (S101). The control unit 20 receives the detection result from various sensors, estimates the sheet size, and detects the same as a detected size.

[0114] The control unit 20 determines whether the sheet widths of the set size and the detected size are the same, i.e., coincide (S102). The control unit 20 performs the determination based on whether the position information of the side regulating plates 53 obtained by the manual sheet feed unit 50 and the width information of the set size coincide. If it is determined that the sheet widths of the set size and the detected size coincide (S102: YES), the control unit 20 determines whether the trailing edge flag sensor 522 is at a protruded position (S103). If it is determined that the trailing edge flag sensor 522 is at the protruded position (S103; YES), the control unit 20 determines whether the length, i.e., sheet length, of the set size in the sheet feeding direction Df is less than 220.0 mm (S104). If it is determined that the sheet length of the set size is less than 220.0 mm (S104; YES), the control unit 20 starts the feeding operation assuming that the set size and the detected size coincide (S105).

[0115] If it is determined in S103 that the trailing edge flag sensor 522 is not at the protruded position (S103; NO), the control unit 20 determines whether the sheet length of the set size is 220.0 mm or more (S106). If it is determined that the sheet length of the set size is 220.0 mm or more (S106; YES), the control unit 20 starts the feeding operation assuming that the set size and the detected size coincide (S105).

[0116] If it is determined in S102 that the sheet widths of the set size and the detected size do not coincide (S102; NO), the control unit 20 determines that the sheet sizes differ, i.e., do not coincide, and notifies a warning that the sheet sizes do not coincide to the operation portion 23 (S107). Similarly, if it is determined in S104 that the sheet length of the set size is not less than 220.0 mm (S104; NO), the control unit 20 determines that the sheet sizes do not coincide, and notifies a warning that the sheet sizes do not coincide to the operation portion 23 (S107). Similarly, if it is determined in S106 that the sheet length of the set size is not equal to or greater than 220.0 mm (S106; NO), the control unit 20 determines that the sheet sizes do not coincide, and notifies a warning that the sheet sizes do not coincide to the operation portion 23 (S107).

[0117] In the present embodiment, the operation portion 23 is one example of a warning output portion, and outputs a warning by display or sound. In the present embodiment, the operation portion 23 is one example of a display portion, and can display a warning regarding the sheet length. Further, to output a warning notice, or to display a warning, from the operation portion 23 is an example of a noncoincidence processing performed by the control unit 20. The warning output portion is not limited to the operation portion 23, and for example, it may be an interface when outputting information to the host device 24 or other devices.Feeding Operation of a Non-Regular Size Sheet

[0118] In the image forming apparatus 1 according to the present embodiment, a maximum regular size that can be placed on the manual sheet feed unit 50 is set to A3 size (sheet length of 420.0 mm × sheet width of 297.0 mm). The sheet length of a maximum regular size sheet in the sheet feeding direction Df is referred as the first length L11. The first length L11 is the sheet length of a maximum regular size sheet in the present example, but the present technique is not limited thereto, and it can be a sheet length of an arbitrary regular size sheet.

[0119] Meanwhile, an irregular size sheet can be conveyed by having a sheet size that is not a regular size, i.e., irregular size, entered by a print job or through input of a user via the operation portion 23. FIG. 26 illustrates a state in which the sheet S is supported on the manual sheet feed unit 50, and the supported sheet S is an irregular size sheet having a sheet length of 600.0 mm × sheet width of 297.0 mm. The sheet S has its leading edge supported by the leading edge regulating portion 515 of the manual sheet feed unit 50, and the trailing edge of the sheet S is not supported since it is greater than the manual sheet feed unit 50, such that it is hung down from the most upstream position in the conveyance direction. In this state, the sheet S having a low stiffness may be in a state curved greatly upward on the manual sheet feed unit 50. In this case, the sheet S is curved and does not come into contact with the sheet contact portion 521c of the trailing edge detection flag 521, such that the trailing edge detection flag 521 stays in the protruded position.

[0120] Next, a processing procedure including the possibility of feeding the long sheet SL using the manual sheet feed portion 40 will be described with reference to the flowchart of FIG. 27. FIG. 27 illustrates a processing procedure from when a print job from the manual sheet feed portion 40 is entered to the control unit 20 until the conveyance operation is started. In the present description, a case where the extension unit 60 is not used is described, but for example, a similar processing may be executed in a case where the extension unit 60 is used to feed the long sheet SL having a sheet length of 900 mm or 1200 mm. In that case, the extension unit 60 supports the sheet S having a sheet length longer than the first length L11 together with the first sheet supporting surface 52. That is, in a state attached to the manual sheet feed unit 50, the extension unit 60 includes the third sheet supporting surface 62a serving as an example of an upper sheet supporting portion that supports the long sheet SL above the first sheet supporting surface 52.

[0121] The user enters a size information, i.e., set size, of the sheet S to be used via a setting through a print job sent from the host device 24 or via a setting entered through an input operation using the operation portion 23 of the apparatus (S200). The control unit 20 determines whether the sheet length of the set size is longer than a sheet length, for example, 450.0 mm, allowed as the maximum regular size (S201).

[0122] If it is determined that the sheet length of the set size is longer than the sheet length allowed as the maximum regular size (S201; YES), the control unit 20 starts a feeding operation (S202). That is, if the sheet length of the set size is longer than the sheet length allowed as the maximum regular size, as illustrated in FIG. 26, the sheet S may be curved upward such that the trailing edge detection flag 521 is maintained at the protruded position, and in consideration of such a case, feeding is started regardless of the position of the trailing edge detection flag 521. Meanwhile, if it is determined that the sheet length of the set size is not longer than the sheet length allowed as the maximum regular size (S201; NO), the control unit 20 advances to a regular size processing illustrated in FIG. 25 (S203).

[0123] That is, the control unit 20 can execute a noncoincidence processing in a case where the detection result of the trailing edge detection unit 520 and a set sheet length of the sheet according to an entered sheet information corresponding to the manual sheet feed unit 50 do not coincide. In a case where the set sheet length is shorter than the first length L11, i.e., sheet length of a maximum regular size, and where the detection result of the trailing edge detection unit 520 and the set sheet length coincide, the control unit 20 will not execute the noncoincidence processing. In this case, the feeding operation is started without displaying a warning on the operation portion 23. In a case where the set sheet length is shorter than the first length L11 and the detection result of the trailing edge detection unit 520 does not coincide with the set sheet length, the control unit 20 executes a noncoincidence processing. Further, in a case where the set sheet length is longer than the first length L11, the control unit 20 will not execute the noncoincidence processing. Thereby, even in a case where the sheet length of the set size is longer than the sheet length allowed as the maximum regular size, an erroneous warning notice can be prevented from being output.

[0124] As described above, according to the manual sheet feed portion 40 of the present embodiment, the extension unit 60 is narrower than the manual sheet feed unit 50 in the sheet width direction W, and longer than the manual sheet feed unit 50 in the sheet feeding direction Df. Therefore, the size of the manual sheet feed portion 40 in the sheet width direction W after attaching the extension unit 60 can be reduced. Further, the tray insertion portion 721 is narrower than the manual sheet feed unit 50 in the sheet width direction W. Therefore, it becomes possible to attach the extension unit 60 while reducing the contact area between the manual sheet feed unit 50 and the extension unit 60 and suppressing the influence on the exterior of the manual sheet feed unit 50. Therefore, the extension unit 60 capable of being attached and detached while suppressing the occurrence of damages on the decorative surface can be realized.

[0125] According to the present disclosure, the apparatus may be downsized in the sheet width direction.Other Embodiments

[0126] The present embodiment was described based on a case where the trailing edge detection flag 521 is disposed at one location, but the present technique is not limited thereto, and a plurality of detection flags can be disposed. According further to the present embodiment, an example of a case where the operation is changed if the size information designated by the user is longer than the length allowed as the maximum regular size, as illustrated in FIG. 27, but the present technique is not limited thereto. For example, it may be possible to set a function to selectively switch between the operation illustrated in FIG. 25 and the operation illustrated in FIG. 27, and to provide this function selectively by having a service technician change the settings of the apparatus, for example.

[0127] According to the embodiment described above, as illustrated in FIG. 27, after setting the set size, the control unit 20 determines whether the sheet length of the set size is longer than a sheet length of 450.0 mm, for example, that is allowed as the maximum regular size (S201). However, the present technique is not limited thereto, and for example, it may be possible to determine whether the sheet widths of the set size and the detected size coincide prior to the processing of S201. The processing procedure of such a case is illustrated in FIG. 28. A case where the extension unit 60 is not used is illustrated, but a similar processing may be executed in a case where the extension unit 60 is used.

[0128] FIG. 28 illustrates a processing procedure from a state where a print job from the manual sheet feed portion 40 is entered to the control unit 20 until the conveyance operation is started. The user enters a size information, i.e., set size, of the sheet S to be used via a setting entered through a print job sent from the host device 24 or via a setting entered through an input operation using the operation portion 23 of the apparatus (S300). The control unit 20 receives the print job conveyed from the manual sheet feed portion 40 or based on the input operation, and executes the sheet size detection (S301). The control unit 20 receives the detection results from various sensors, estimates the sheet size, and detects the same as a detected size.

[0129] The control unit 20 determines whether the sheet widths of the set size and the detected size coincide (S302). In this case, the control unit 20 performs the determination based on whether the positional information of the side regulating plates 53 obtained by the manual sheet feed unit 50 and the width information of the set size coincide. If it is determined that the sheet widths of the set size and the detected size coincide (S302; YES), the control unit 20 executes S201 to S203 illustrated in FIG. 27. If it is determined that the sheet widths of the set size and the detected size do not coincide (S302; NO), the control unit 20 determines that the sheet sizes do not coincide, and notifies a warning that the sizes do not coincide to the operation portion 23 (S303).

[0130] That is, the control unit 20 can execute the noncoincidence processing in a case where the detection result of the sheet width detection unit 519 and the set sheet width of the sheet based on the entered sheet information corresponding to the manual sheet feed unit 50 do not coincide. The control unit 20 executes the noncoincidence processing in a case where the detection result of the sheet width detection unit 519 and the set sheet width do not coincide. The control unit 20 does not execute the noncoincidence processing in a case where the detection result of the sheet width detection unit 519 and the set sheet width coincide, where the set sheet length is shorter than the first length L11, and where the detection result of the trailing edge detection unit 520 and the set sheet length coincide. Further, the control unit 20 executes the noncoincidence processing in a case where the detection result of the sheet width detection unit 519 and the set sheet width coincide, where the set sheet length is shorter than the first length L11, and where the detection result of the trailing edge detection unit 520 and the set sheet length do not coincide. Further, the control unit 20 does not execute the noncoincidence processing in a case where the detection result of the sheet width detection unit 519 and the set sheet width coincide, and where the set sheet length is longer than the first length L11.

[0131] According to the present processing procedure, whether the sheet widths coincide is determined before determining whether the sheet is a long sheet in S201, and a warning is notified if the sheet widths do not coincide. Therefore, rapid processing can be realized compared to a case where whether the sheet widths coincide is determined in a regular size processing after determining that the regular size sheet is not a long sheet.

[0132] While the present disclosure has been described with reference to embodiments, it is to be understood that the present disclosure is not limited to the disclosed embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

[0133] This application claims the benefit of Japanese Patent Application No. 2025-028754, filed February 26, 2025 which is hereby incorporated by reference herein in its entirety.

Examples

Embodiment Construction

[0046]An image forming apparatus 1 according to the present embodiment will be described below with reference to FIGS. 1 to 28. At first, a schematic configuration of the image forming apparatus 1 according to the present embodiment will be described with reference to FIG. 1. FIG. 1 is a cross-sectional view illustrating a schematic configuration of the image forming apparatus 1 according to the present embodiment taken from a front side. The image forming apparatus 1 is a tandem-type, intermediate transfer-type laser beam printer adopting an electrophotographic process. The image forming apparatus 1 can form and output a full-color or mono-color image corresponding to a print image data output from a host device 24 (refer to FIG. 2) connected to a control unit 20 on a sheet S serving as a recording medium.

Image Forming Apparatus

[0047]The image forming apparatus 1 includes an apparatus body 201A, and an image forming unit 201B for forming an image on the sheet S. An image reading ap...

Claims

1. A sheet feeding apparatus comprising:a first sheet supporting unit including a first sheet supporting surface configured to support a sheet;a feeding portion configured to feed the sheet supported on the first sheet supporting surface in a sheet feeding direction; anda second sheet supporting unit detachably attached to the first sheet supporting unit, and including a second sheet supporting surface configured to support a sheet and positioned upstream of the first sheet supporting surface in the sheet feeding direction in an attached state attached to the first sheet supporting unit,wherein the second sheet supporting surface isnarrower than the first sheet supporting surface in a width direction orthogonal to the sheet feeding direction, andlonger than the first sheet supporting surface in the sheet feeding direction.

2. The sheet feeding apparatus according to claim 1,wherein the first sheet supporting unit includes an insertion port at an upstream end in the sheet feeding direction,wherein the second sheet supporting unit includes an insertion portion configured to be inserted to the insertion port to attach the second sheet supporting unit to the first sheet supporting unit, andwherein the insertion portion is narrower than the first sheet supporting surface in the width direction.

3. The sheet feeding apparatus according to claim 2,wherein, in a state attached to the first sheet supporting unit, the second sheet supporting unit includesa first supporting portion including the second sheet supporting surface extending upstream in the sheet feeding direction from the first sheet supporting surface,a second supporting portion including a third sheet supporting surface disposed upstream of the second sheet supporting surface in the sheet feeding direction and configured to support a long sheet together with the first sheet supporting surface and the second sheet supporting surface, anda bending portion connecting the second supporting portion continuously to the first supporting portion in an upwardly bent state, andwherein the first supporting portion is narrower than the first sheet supporting surface in the width direction.

4. The sheet feeding apparatus according to claim 3, wherein the second supporting portion and the bending portion are narrower than the first sheet supporting surface in the width direction.

5. The sheet feeding apparatus according to claim 3,wherein the second supporting portion and the bending portion are formed of a linear member having a U shape, end portions of the linear member being positioned on a downstream side of the linear member in the sheet feeding direction and attached to the first supporting portion,wherein the end portions are bent mutually inward in the width direction,wherein the first supporting portion includes two supporting holes opened outward at both side portions in the width direction, and retaining portions arranged on an outer side of each of the supporting holes in the width direction, andwherein the end portions of the linear member are inserted into each of the supporting holes from an outer side in the width direction, and retained by being prevented from coming out toward the outer side in the width direction by the retaining portions.

6. The sheet feeding apparatus according to claim 3, wherein a distance between a downstream edge of the first sheet supporting surface in the sheet feeding direction and the bending portion is longer than a distance between the bending portion and an uppermost portion positioned at an uppermost position of the second supporting portion.

7. The sheet feeding apparatus according to claim 3,wherein, in a state where the second sheet supporting unit is attached to the first sheet supporting unit,the second supporting portion includes an uppermost portion positioned at an uppermost position of the second supporting portion between an upstream end and a downstream end in the sheet feeding direction.

8. The sheet feeding apparatus according to claim 2,wherein the first sheet supporting unit includes a guide portion configured to guide the insertion portion at an interior of the insertion port, andwherein the guide portion is configured to come into contact with and guide the insertion portion in an inserted state from both sides in the width direction, and to position the insertion portion in the width direction.

9. The sheet feeding apparatus according to claim 2,wherein the first sheet supporting unit includes a lower portion member that is arranged below the insertion port, that defines a lower portion of the insertion port, and that includes a lower surface of the first sheet supporting unit, andwherein the second sheet supporting unit includes a lower supporting portion disposed below the insertion portion and configured to sandwich the lower portion member with the insertion portion in a state where the insertion portion is inserted to the insertion port.

10. The sheet feeding apparatus according to claim 9, wherein the lower supporting portion is narrower than the first sheet supporting surface in the width direction.

11. The sheet feeding apparatus according to claim 1,wherein the first sheet supporting unit includes an engaged portion,wherein the second sheet supporting unit includes an engagement member configured to be displaced between an engaged position and a retracting position retracted from the engaged position, andwherein, in a state where the second sheet supporting unit is attached to the first sheet supporting unit, the engagement member is configured to be engaged with the engaged portion by being positioned at the engaged position such that the second sheet supporting unit is regulated from being detached from the first sheet supporting unit, and the engagement member is configured to be disengaged from the engaged portion by being positioned at the retracting position such that the second sheet supporting unit is allowed to be detached from the first sheet supporting unit.

12. The sheet feeding apparatus according to claim 11,wherein the second sheet supporting unit includesan urging member configured to urge the engagement member toward the engaged position, andan operation portion configured to operate the engagement member toward the retracting position.

13. An image forming apparatus comprising:the sheet feeding apparatus according to claim 1; andan image forming unit configured to form an image on a sheet.

14. An extension supporting unit detachably attached to a sheet supporting unit including a first sheet supporting surface configured to support a sheet, the extension supporting unit comprising a second sheet supporting surface configured to support a sheet and positioned upstream of the sheet supporting surface in a sheet feeding direction by a feeding portion in an attached state attached to the sheet supporting unit,wherein the second sheet supporting surface isnarrower than the first sheet supporting surface in a width direction orthogonal to the sheet feeding direction, andlonger than the first sheet supporting surface in the sheet feeding direction.

Images