Sheet feeding device, image forming apparatus, extension support unit

Abstract

It can support long sheets while suppressing feeding problems with standard-sized sheets. [Solution] The extension unit 60, when mounted on the manual feed unit 50, has a first extension support section 61 having a second sheet support section 61a that extends upstream from the first sheet support section 52 in the sheet feed direction Df, a second extension support section 62 having a third sheet support section 62a that is located upstream of the second sheet support section 61a in the sheet feed direction Df and supports a long sheet together with the first sheet support section 52 and the second sheet support section 61a, and a bent section 63 that connects the second extension support section 62 to the first extension support section 61 in an upwardly folded state. The first extension support section 61 has a length that extends upstream of the upstream end of a standard sheet SN in the sheet feed direction DF, with the standard sheet SN supported by the first sheet support section 52 and the second sheet support section 61a.

Description

[Technical Field]

[0001] The present invention relates to a sheet feeding apparatus that feeds sheets, an image forming apparatus provided with the sheet feeding apparatus, and an extension support unit applied to the sheet feeding apparatus. [Background Art]

[0002] Image forming apparatuses such as printers, copiers, facsimile machines, and multifunction peripherals combining these functions are provided with a sheet storage section called a feeding cassette. Printing sheets are stored in this sheet storage section. Generally, one or more sheet storage sections are provided inside a large-sized image forming apparatus. This type of sheet storage section is formed into a shape capable of holding printing sheets of so-called standard sizes such as A-series sizes, B-series sizes, and letter size. On the other hand, in response to a demand for printing images on sheets of non-standard sizes (hereinafter also referred to as non-standard size sheets), conventional image forming apparatuses having a manual feed tray capable of placing non-standard size sheets on the side surface have become widespread. A user can feed a non-standard size sheet from the manual feed tray to an image forming section of the image forming apparatus.

[0003] Furthermore, there are cases where a sheet having a size exceeding the sheet length of a standard size sheet in the sheet feeding direction (about 450 mm or more) (hereinafter also referred to as a long sheet) is placed on the manual feed tray. For this reason, a technique for mounting a long sheet tray compatible with long sheets on a manual feed tray has been developed (see Patent Document 1). In such a long sheet tray, the long sheet is held in a curved posture in order to avoid an increase in size of the apparatus. In this configuration, by providing a bent frame on the sheet support surface of the long sheet tray, when a long sheet is placed, the sheet follows the bent frame, and the long sheet is supported in a curved posture. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2017-75013 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, in the configuration described in Patent Document 1, when a large, standard-sized sheet, such as A3 size, is placed on the tray for long sheets, the standard-sized sheet is supported in a curved position, similar to the long sheet. In this case, compared to when the sheet is supported flat, the component of the sheet's weight in the transport direction increases, and the change in the sheet's posture affects the sheet transport performance, potentially causing feeding problems such as double feeding or non-feeding.

[0006] The present invention aims to provide a sheet feeding device, an image forming device, and an extension support unit that can support long sheets while suppressing feeding failures of standard-sized sheets. [Means for solving the problem]

[0007] A first aspect of the present invention comprises a sheet support unit having a first sheet support portion for supporting a sheet, a feeding portion for feeding a sheet supported by the first sheet support portion in the sheet feeding direction, and an extension support unit detachably attached to the sheet support unit and, when attached to the sheet support unit, located upstream of the first sheet support portion in the sheet feeding direction and supporting a sheet, wherein the extension support unit, when attached to the sheet support unit, extends upstream from the first sheet support portion in the sheet feeding direction, A sheet feeding device comprising: a first extension support section having a section; a second extension support section having a third sheet support section positioned upstream of the second sheet support section in the sheet feeding direction and supporting a long sheet together with the first and second sheet support sections; and a bent section that connects the second extension support section to the first extension support section in an upwardly folded state, wherein the first extension support section has a length that extends upstream of the upstream end of a standard-sized sheet in the sheet feeding direction, with the sheet being supported by the first and second sheet support sections.

[0008] A second aspect of the present invention is an image forming apparatus characterized by comprising the above-described sheet feeding device and an image forming unit for forming an image on a sheet.

[0009] A third aspect of the present invention is an extension support unit that is detachably attached to a sheet support unit having a first sheet support portion for supporting a sheet, and which, when attached to the sheet support unit, is located upstream of the first sheet support portion in the sheet feeding direction by a feeding portion and supports the sheet, comprising: a first extension support portion having a second sheet support portion extending upstream from the first sheet support portion in the sheet feeding direction; a second extension support portion having a third sheet support portion arranged upstream of the second sheet support portion in the sheet feeding direction and supporting a long sheet together with the first sheet support portion and the second sheet support portion; and a bent portion that connects the second extension support portion to the first extension support portion in an upwardly folded state, wherein the first extension support portion has a length that extends upstream of the upstream end of a sheet of a standard size when the sheet is supported by the first sheet support portion and the second sheet support portion in the sheet feeding direction. [Effects of the Invention]

[0010] According to the present invention, it is possible to support long sheets while suppressing feeding problems with standard-sized sheets. [Brief explanation of the drawing]

[0011] [Figure 1] This is a cross-sectional view showing an image forming apparatus according to an embodiment. [Figure 2] This is a block diagram showing the control system of an image forming apparatus according to an embodiment. [Figure 3] This is a perspective view showing the feeding unit according to an embodiment. [Figure 4] This is a perspective view showing an extension unit according to an embodiment. [Figure 5] This is a perspective view showing a manual feed unit and an extension unit according to an embodiment, where (a) is before installation and (b) is after installation. [Figure 6] This figure shows a long sheet being supported by a manual feeding unit equipped with an extension unit according to the embodiment, where (a) is a perspective view and (b) is a front view. [Figure 7] This figure shows a standard sheet being supported on a manual feed unit equipped with an extension unit according to the embodiment, where (a) is a perspective view and (b) is a front view. [Figure 8] This is an exploded perspective view showing an extension unit according to an embodiment. [Figure 9] This figure shows the mounting portion of the extension unit according to the embodiment, where (a) is an exploded perspective view and (b) is a perspective view. [Figure 10] This is an exploded perspective view showing an extension unit according to an embodiment. [Figure 11] This is a plan view showing the mounting portion of the extension unit according to the embodiment, when the hook is in the closed position. [Figure 12] This is a plan view showing the mounting portion of the extension unit according to the embodiment, with the hook in the open position. [Figure 13] This figure shows the mounting portion of the manual feed unit according to the embodiment, where (a) is a perspective view, (b) is a plan view, and (c) is a cross-sectional view. [Figure 14] This is a plan view showing the state before the hook contacts the hook engagement wall when attaching the mounting portion of the extension unit according to the embodiment to the mounting portion of the manual feed unit. [Figure 15] This is a plan view showing the state in which the hook contacts the hook engagement wall and rotates when the mounting portion of the extension unit according to the embodiment is attached to the mounting portion of the manual feed unit. [Figure 16] This is a plan view showing the mounting portion of the extension unit according to the embodiment attached to the mounting portion of the manual feed unit. [Figure 17] This is a plan view showing the hook in the extended position when the mounting portion of the extension unit according to the embodiment is detached from the mounting portion of the manual feed unit. [Figure 18] This is a plan view showing the state in which the hook has been detached from the hook engagement wall when the mounting portion of the extension unit according to the embodiment is detached from the mounting portion of the manual feed unit. [Figure 19]It is a plan view showing a state where the mounting portion of the extension unit according to the embodiment is detached from the mounted portion of the manual feeding unit. [Figure 20] It is a perspective view showing the manual feeding unit according to the embodiment. [Figure 21] It is a perspective view from below showing a rack-and-pinion mechanism for moving the side regulating plate of the manual feeding unit according to the embodiment. [Figure 22] It is a perspective view showing the trailing end detection unit of the manual feeding unit according to the embodiment. [Figure 23] It is a cross-sectional view showing the trailing end detection flag of the manual feeding unit according to the embodiment, wherein (a) shows the flag when positioned at a protruding position, and (b) shows the flag when positioned at a retracted position. [Figure 24] It is a cross-sectional view showing the state of the trailing end detection flag of the manual feeding unit according to the embodiment, wherein (a) shows the state when supporting an A4-size sheet, and (b) shows the state when supporting an A3-size sheet. [Figure 25] It is a flowchart showing the procedure for feeding a sheet using the manual feeding unit according to the embodiment. [Figure 26] It is a cross-sectional view showing the state of the trailing end detection flag when supporting a long sheet in the manual feeding unit according to the embodiment. [Figure 27] It is a flowchart showing the procedure for feeding a long sheet using the manual feeding unit according to the embodiment. [Figure 28] It is a flowchart showing the procedure when also determining the sheet width when feeding a long sheet using the manual feeding unit according to the embodiment. DESCRIPTION OF THE EMBODIMENTS

[0012] The image forming apparatus 1 of this embodiment will be described below with reference to Figures 1 to 28. First, the schematic configuration of the image forming apparatus 1 according to this embodiment will be described with reference to Figure 1. Figure 1 is a cross-sectional view taken from the front, showing the schematic configuration of the image forming apparatus 1 according to this embodiment. The image forming apparatus 1 is a tandem-intermediate transfer type laser beam printer that utilizes an electrophotographic process. The image forming apparatus 1 can form and output full-color or monochrome images corresponding to print image data output from a host device 24 (see Figure 2) connected to a control unit 20 onto a recording medium sheet S.

[0013] [Image forming apparatus] The image forming apparatus 1 comprises an apparatus body 201A and an image forming unit 201B for forming an image on a sheet S. An image reading device 202 is provided above the apparatus body 201A, installed substantially horizontally. A discharge space V for sheet discharge is formed between the image reading device 202 and the apparatus body 201A.

[0014] [Feeding Unit] The sheets S are stored, for example, in the feed cassettes 7A and 7B of the cassette feed units 9A and 9B according to their size, or are supported in the manual feed section 40.

[0015] The cassette feeding units 9A and 9B each have a feeding cassette 7A and 7B for containing the sheets S, and a feeding section 6A and 6B for feeding the sheets S from the feeding cassette 7A and 7B. Although the cassette feeding units 9A and 9B contain different sized sheets S, the configuration of each feeding section 6A and 6B is the same, so here we will describe the feeding section 6A. The feeding section 6A has a pickup roller 2 and a pair of separation rollers 5 consisting of a feed roller and a retard roller for separating the sheets S sent out from the pickup roller 2. The sheets S separated one by one by the pair of separation rollers 5 are transported by a first pair of pre-registration rollers 11 (first pair of pre-registration rollers) to a pair of registration rollers 13 (pair of registration rollers).

[0016] The manual feeding unit 40 is an example of a sheet feeding device and includes a manual feeding unit 50, a feeding unit 41, and an extension unit 60. In this embodiment, the manual feeding unit 50 is defined as the sheet feeding direction Df in which the loaded sheets S are fed, and the direction perpendicular to the sheet feeding direction Df, i.e., the width direction of the loaded sheets S, is defined as the sheet width direction W.

[0017] The manual feed unit 50 is an example of a sheet support unit and includes a manual feed tray 51 and a first sheet support portion 52 formed on the upper surface of the manual feed tray 51, which is a sheet support surface for supporting the sheet S. The manual feed unit 50 can be opened and closed by rotating relative to the main body of the device 201A and is provided to be displaceable between a closed position and an open position. In the open state, the manual feed tray 51 supports the sheet S loaded on the first sheet support portion 52. This is an example of the first sheet support portion. The manual feed tray 51 is also provided with a pair of side regulating plates 53 that are movable in the sheet width direction W on the manual feed unit 50 and contact the end of the sheet in the sheet width direction W of the sheet supported by the first sheet support portion 52 to regulate the position of the sheet. For example, an air handling fan unit (not shown) may be provided on these side regulating plates 53.

[0018] Figure 3 is a perspective view showing the manual feed unit 50 and feed section 41 according to this embodiment. As shown in Figure 3, the feed section 41 feeds the sheets S supported by the first sheet support section 52 of the manual feed tray 51 to the second pre-registration roller pair 12 (second pre-registration roller pair). The feed section 41 has a pickup roller 42 and a separation roller pair 43 consisting of a feed roller and a retard roller for separating the sheets S sent out from the pickup roller 42. The sheets S separated one by one by the separation roller pair 43 are transported to the registration roller pair 13 by the second pre-registration roller pair 12. That is, the feed section 41 feeds the sheets S supported by the first sheet support section 52 in the sheet feeding direction Df.

[0019] As shown in Figure 1, the extension unit 60 is an example of an extension support unit and is detachably attached to the manual feed unit 50 in a direction along the sheet feeding direction Df. When the extension unit 60 is attached to the manual feed unit 50, it is located upstream of the manual feed tray 51 in the sheet feeding direction Df and supports the sheet S. The extension unit 60 has a first extension support section 61, a second extension support section 62, and a bent section 63. The first extension support section 61 has a second sheet support section 61a, which is a sheet support surface that extends upstream from the first sheet support section 52 in the sheet feeding direction Df. The second extension support section 62 has a third sheet support section 62a, which is located upstream of the second sheet support section 61a in the sheet feeding direction Df and supports the long sheet SL together with the first sheet support section 52 and the second sheet support section 61a.

[0020] The bent section 63 is formed by continuing the second extension support section 62 in a state where it is bent upward relative to the first extension support section 61. That is, the first extension support section 61 includes the section from the downstream end of the second sheet support section 61a to the bent section 63 in the sheet feeding direction Df. The second extension support section 62 includes the section from the bent section 63 to the uppermost end 62b of the third sheet support section 62a. The extension unit 60 will be described later.

[0021] In this embodiment, the extension unit 60 is described as being attached to the manual feed unit 50 and is described as part of the image forming apparatus 1. However, it is not limited to this, and the extension unit 60 may be treated as an optional device not included in the image forming apparatus 1. In this embodiment, the state shown in Figure 1, in which the extension unit 60 is attached to the manual feed unit 50, is referred to as the attached state. The state in which the extension unit 60 is detached from the manual feed unit 50 is referred to as the detached state.

[0022] [Image Forming Unit] The image forming unit 201B forms an image on the sheet S, which is fed by the cassette feeding unit 230 or the manual feeding unit 50 and transported by the register roller pair 13. The image forming unit 201B has four process cartridges PY, PM, PC, and PK, which each form toner images of four colors: yellow (Y), magenta (M), cyan (C), and black (K), as well as an exposure unit 30 and an intermediate transfer belt 36. The four process cartridges PY, PM, PC, and PK have the same configuration except for the color of the image they form. Therefore, only the configuration and image forming process of process cartridge PY will be described, and the descriptions of process cartridges PM, PC, and PK will be omitted. The image forming unit 201B also has a secondary transfer unit 38 and a fuser unit 201E located above the process cartridges PY, PM, PC, and PK. The toner cartridge 35 supplies toner to the developing roller 34.

[0023] The PY process cartridge includes a photosensitive drum 32, which is a drum-type electrophotographic photoreceptor, a charging roller 33, and a developing roller 34. The photosensitive drum 32 is rotatably supported by the image forming apparatus 1 and is rotationally driven by a driving means (not shown). The photosensitive drum 32 is constructed by providing a photoconductive layer such as OPC (organic photoconductive material) on the outer surface of an aluminum cylinder. The charging roller 33 charges the photosensitive drum 32. The charging roller 33 is composed of a core metal and a conductive elastic member surrounding it, and is positioned in contact with the surface of the photosensitive drum 32 and rotates in a driven manner, and a charging bias is applied by a power supply (not shown). The developing roller 34 deposits toners of different colors (yellow, magenta, cyan, and black) for each process cartridge PY, PM, PC, and PK onto the surface of the photosensitive drum 32. The developing roller 34 deposits toner onto the electrostatic latent image on the surface of the photosensitive drum 32, developing the electrostatic latent image and forming a toner image on the surface of the photosensitive drum 32.

[0024] The exposure unit 30 houses a laser light source that emits laser light and various optical components for guiding 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 surface of the charged photosensitive drum 32 with laser light based on image information to form an electrostatic latent image.

[0025] The secondary transfer section 38 includes an intermediate transfer belt 36 wrapped around a drive roller 36a and a tension roller 36b. Inside the intermediate transfer belt 36 is a primary transfer roller 39 that contacts the intermediate transfer belt 36 at a position opposite the photosensitive drum 32. Here, the intermediate transfer belt 36 rotates in the direction of the arrow by the drive roller 36a, which is driven by a drive unit (not shown). A secondary transfer roller 37 is provided at a position opposite the drive roller 36a of the secondary transfer section 38 for transferring the color image formed on the intermediate transfer belt 36 to the sheet S.

[0026] A fixing unit 201E is positioned above the secondary transfer roller 37, and above this fixing unit 201E are a first discharge roller pair 225a, a second discharge roller pair 225b, and a double-sided reversal unit 201F. The double-sided reversal unit 201F is an example of a re-transport unit, and it reverses the front and back sides of the sheet S on which the image has been formed by the image forming unit 201B, transports it, and transports it to the second pre-resist roller pair 12. The double-sided reversal unit 201F has a reversible reversal roller pair 222 and a re-transport passage 224 that transports the sheet S on which the image has been formed on the first side back to the image forming unit 201B. An operation unit 23 that receives operations from the user is provided at the top of the image forming apparatus 1. The operation unit 23 employs a touch panel system that combines display and input functions. The operation unit 23 is connected to the control unit 20 and accepts various operations from the user, such as inputting various information about the sheet to be used for printing (sheet type information, sheet basis weight information, sheet size information, etc.), and issuing instructions to start or interrupt printing (see Figure 2).

[0027] [Control System] Next, the control unit 20 and control system of the image forming apparatus 1 will be explained using Figure 2. As shown in Figure 2, the control unit 20 has various functional units such as a CPU 21 (Central Processing Unit), memory 22, image forming control unit 25, sheet transport control unit 26, and sensor control unit 27. The CPU 21 realizes various processes performed by the image forming apparatus 1 by executing predetermined control programs and the like. The memory 22 is, for example, RAM (Random Access Memory) or ROM (Read-only memory), and stores various programs and various data in a predetermined storage area.

[0028] The image forming control unit 25 issues instructions to the image forming unit 201B, including the exposure unit 30, to control image formation. The sheet transport control unit 26 issues instructions to the first pre-resist motor 101, the second pre-resist motor 102, the resist motor 103, etc., to control the drive of various transport rollers and control the transport of the sheet S. The sensor control unit 27 controls the start and stop of detection by the sheet presence sensor 104, etc., and receives the detection results of each sensor. The control unit 20 is connected to the operation unit 23. It can also be configured to receive various information about the sheets used for printing via a host device 24 such as a personal computer, image scanner, or facsimile connected via a network.

[0029] [Image Formation Process] Next, the image forming operation of the image forming apparatus 1 will be described. First, when the image forming apparatus 1 receives image data of the original to be printed, the image information is processed and then converted into an electrical signal and transmitted to the exposure unit 30 of the image forming section 201B. In the image forming section 201B, the surface of the photosensitive drum 32, whose surface is uniformly charged to a predetermined polarity and potential by the charging roller 33, is sequentially exposed by a laser. As a result, electrostatic latent images of yellow, magenta, cyan, and black are sequentially formed on the photosensitive drum 32 of each process cartridge PY, PM, PC, and PK, respectively.

[0030] Next, this electrostatic latent image is developed and visualized using each color toner, and the primary transfer bias applied to the primary transfer roller 39 sequentially superimposes and transfers the toner images of each color on each photosensitive drum 32 onto the intermediate transfer belt 36. As a result, a toner image is formed on the intermediate transfer belt 36.

[0031] In parallel with this toner image formation operation, the sheets S are fed one by one by the cassette feeding units 9A, 9B or the manual feed unit 50. Sheets S fed from the cassette feeding units 9A, 9B pass through the first pre-registration roller pair 11 and are transported to the registration roller pair 13. The first pre-registration roller pair 11 and the registration roller pair 13 correct the skew of the sheet S. Specifically, the leading edge of the transporting sheet S is brought into contact with the nip of the stopping registration roller pair 13. The first pre-registration roller pair 11 further transports the sheet S to form a loop and correct the skew. Similarly, sheets S fed from the manual feed unit 50 pass through the second pre-registration roller pair 12 and are transported to the registration roller pair 13. The second pre-registration roller pair 12 and the registration roller pair 13 correct the skew of the sheet S. In this embodiment, the diagonal correction unit 10 includes the first pre-resist roller pair 11, the second pre-resist roller pair 12, and the resist roller pair 13.

[0032] The register roller pair 13 transports the sheet S to the secondary transfer section 38 in time with the transfer of the toner image on the intermediate transfer belt 36 to the sheet S. In the secondary transfer section 38, the toner image is transferred onto the sheet S all at once by the secondary transfer bias applied to the secondary transfer roller 37.

[0033] Next, the sheet S onto which the toner image has been transferred is transported to the fuser unit 201E, where, in the roller nip section formed by the pressure roller 220a and the heating roller 220b, the toners of each color are melted and mixed under heat and pressure, and fixed to the sheet S as a color image. The sheet S with the image fixed is discharged into the discharge space V by the first discharge roller pair 225a or the second discharge roller pair 225b located downstream of the fuser unit 201E, and loaded onto the discharge tray 223 protruding from the bottom surface of the discharge space V.

[0034] On the other hand, when forming images on both sides of the sheet S, the sheet S is stopped with the rear end remaining a predetermined distance from the reversing roller pair 222, then the reversing roller pair 222 is reversed, and the sheet is passed through the re-transport passage 224 to the second pre-regulating roller pair 12. Then, it is transported again to the register roller pair 13 to perform skew correction, and the image forming unit 201B performs image forming and fixing on the second surface.

[0035] [Manual feed unit] Next, the manual feed unit 50 of the manual feed section 40 will be described using Figure 3. Figure 3 is a perspective view of the manual feed unit 50 and the feed section 41. As shown in Figure 3, the manual feed tray 51 is provided with a tip restricting section 515 for restricting the tip position in the sheet feed direction Df. The tip restricting section 515 is located downstream of the first sheet support section 52 in the sheet feed direction Df and is displaceable between a contact position and an allowable position. The contact position is the position in which it contacts the downstream end of the sheet S supported by the first sheet support section 52 in the sheet feed direction Df. The allowable position is the position in which it retracts from the contact position and allows the feeding of the sheet S supported by the first sheet support section 52. The tip restricting section 515 is located in the contact position when not feeding and in the allowable position when feeding.

[0036] When the start button on the control panel 23 of the image forming apparatus 1 is pressed, the feeding of sheets S begins. The top sheet S loaded on the manual feed tray 51 is fed by the rotating pickup roller 42 to the separation roller pair 43, which has a feed roller and a retard roller. The leading edge of the sheet S, which has been separated into individual sheets by the separation roller pair 43, is detected by the leading edge detection sensor 505. The sheet S is then fed to the register roller pair 13 by the second pre-register roller pair 12 (see Figure 1). The subsequent operation is the same as that of cassette feeding.

[0037] [Overview of the extension unit] Generally, the largest standard size is 13 inches x 19 inches. In this embodiment, the standard sheet SN is the longest standard sheet among several types of standard-sized sheets, having the longest sheet length in the sheet feeding direction Df. The manual feeding unit 40 may feed long sheets SL that are longer than this standard sheet SN (approximately 483 mm or longer). To feed long sheets SL from the manual feeding unit 40, an attachment called an extension unit 60 is attached to the manual feeding tray 51, as shown in Figure 1. By attaching the extension unit 60, the sheet support surface of the manual feeding tray 51 can be expanded, enabling support for long sheets SL, and allowing long sheets SL up to 1300 mm in length to be fed.

[0038] Next, the extension unit 60 of the manual feed unit 40 will be explained using Figures 4 to 5(b). Figure 4 is a perspective view of the extension unit 60 of the manual feed unit 40, and Figures 5(a) and 5(b) are perspective views of the extension unit 60 when it is attached to the manual feed unit 50. The extension unit 60 has a first extension support part 61, a second extension support part 62 for loading long sheets SL, a bent part 63, and a mounting part 64. The mounting part 64 is detachably attached to a mounting part 54 provided on the manual feed tray 51, and by attaching it, the extension unit 60 is mounted on the manual feed unit 50, making it possible to load long sheets SL up to 1300 mm in length. The configuration of the mounting part 64 and the mounting part 54 will be described later.

[0039] In this embodiment, the first sheet support portion 52 forms a first support surface that abuts against and supports the sheet S, and the second sheet support portion 61a forms a second support surface that abuts against and supports the sheet S. The second support surface, which is the second sheet support portion 61a, is arranged on the same plane as the first support surface, which is the first sheet support portion 52 (see Figure 1). As a result, the sheet S supported by the first sheet support portion 52 and the second sheet support portion 61a is supported flat, and the occurrence of feeding defects such as double feeding and non-feeding can be suppressed.

[0040] In this embodiment, the second extension support portion 62 and the bent portion 63 are made of a metal wire 65, which is an example of a U-shaped linear member with an open end attached to the first extension support portion 61 on the downstream side in the sheet feeding direction Df. The wire 65 is detachably attached to the first extension support portion 61. The bent portion 63 is formed by bending a part of the wire 65 and is provided so as to be continuous with the second extension support portion 62 in a state where it is bent upward relative to the first extension support portion 61. When a pre-formed sheet SN is supported by the first sheet support portion 52 and the second sheet support portion 61a (see Figures 7(a) and (b)), the bent portion 63 is positioned upstream of the upstream end of the pre-formed sheet SN in the sheet feeding direction DF. The bent portion 63 is also positioned below the second sheet support portion 61a. As a result, the standard sheet SN is supported in a flat state, with the upstream end of the sheet feeding direction DF not in contact with the second extension support part 62, thereby suppressing feeding defects such as double feeding or non-feeding.

[0041] In this embodiment, the extension unit 60 is formed to be narrower in the sheet width direction W than the sheet width of the maximum width standard sheet, which has the widest sheet width among multiple types of standard-sized sheets. As a result, when supporting the maximum width standard sheet, there is no area in the sheet width direction W that does not support the sheet S, so the size of the device can be suppressed and frictional resistance to the sheet surface during sheet feeding can be reduced.

[0042] [Long Sheet] Figures 6(a) and 6(b) are perspective and side views of a manual feed unit 50 equipped with an extension unit 60, showing a long sheet SL with a length Df in the sheet feed direction of 1300 mm supported. The leading edge of the long sheet SL is positioned by contacting a leading edge restricting section 515 provided on the manual feed tray 51. The long sheet SL is supported by a sheet support surface formed by the first sheet support section 52 of the manual feed tray 51, the second sheet support section 61a of the first extension support section 61, and the third sheet support section 62a of the second extension support section 62. Here, a bent section 63 is provided at the connection between the first extension support section 61 and the second extension support section 62, such that the upstream side of the second extension support section 62 in the transport direction curves upward, and the long sheet SL is supported on the extension unit 60 in a curved position following the bent section 63. This allows the manual feeding section 40 to be made smaller compared to the case where the long sheet SL is supported so that it is flat.

[0043] Here, the distance between the tip restricting portion 515 and the bent portion 63 located at the contact position in the sheet feeding direction Df is defined as the third distance L3, and the distance from the bent portion 63 to the uppermost end 62b of the second extension support portion 62 is defined as the fourth distance L4. In this case, the third distance L3 > the fourth distance L4. As a result, even with a long sheet SL, a large portion can be supported flat, thus enabling stable support.

[0044] Furthermore, the sheet length of the sheet S supported by the first sheet support section 52, the second sheet support section 61a, and the third sheet support section 62a in the sheet feeding direction DF may be longer than the sum of the third distance L3 and the fourth distance L4. In this case, as shown in Figure 6(b), the portion of the sheet S upstream in the sheet feeding direction Df from the portion supported by the third sheet support section 62a is supported by hanging down from the uppermost end 62b of the second extension support section 62. This allows the sheet to be supported by the manual feeding section 40 even when the sheet length is longer than the sum of the third distance L3 and the fourth distance L4.

[0045] [Standard Sheet] Figures 7(a) and 7(b) are perspective and side views, respectively, of a standard-sized sheet SN with a maximum length Df in the sheet feeding direction, supported by a manual feed unit 50 equipped with an extension unit 60. The leading edge of the standard-sized sheet SN is positioned in contact with a leading edge restricting portion 515 provided on the manual feed tray 51. Here, the length Df in the sheet feeding direction between the leading edge restricting portion 515 located at the contact position and the bent portion 63 provided on the second extension support portion 62 of the extension unit 60 (i.e., the upstream end of the first extension support portion 61) is defined as the first distance L1. The length of the standard-sized sheet SN in the sheet feeding direction DF is defined as the second distance L2.

[0046] In this case, the first distance L1 > the second distance L2. That is, the first extension support section 61 has a length that extends upstream of the upstream end of the standard sheet SN in the sheet feeding direction Df, with the standard sheet SN supported by the first sheet support section 52 and the second sheet support section 61a. As a result, the standard sheet SN is supported in a flat state, without the upstream end in the sheet feeding direction DF contacting the second extension support section 62, thereby suppressing feeding defects such as double feeding or non-feeding. In other words, even when a standard sheet SN is loaded with the extension unit 60 attached, the sheet S can be fed in a flat position without conforming to the curved section 63. In this embodiment, the standard size with the maximum sheet length in the sheet feeding direction Df is 12 inches x 18 inches. For this reason, the second distance L2 is 457.2 mm, while the first distance L1 is set to approximately 470 mm.

[0047] [Details of the extension unit] The detailed configuration of the extension unit 60 will be described below using Figures 8 to 10. Figure 8 is an exploded perspective view illustrating the configuration of the extension unit 60. The first extension support section 61 of the extension unit 60 includes a hook 702 for attachment to the manual feed tray 51, a hook biasing member 703 for biasing the hook 702, and a cover section 704 for housing the hook 702 and the hook biasing member 703. Furthermore, a second extension support section 62 for supporting a long sheet SL is detachably attached to the first extension support section 61, and by attaching it, it is possible to support a long sheet SL up to 1300 mm.

[0048] Figure 9(a) is an exploded perspective view from below showing the mounting portion 64, Figure 9(b) is an exploded perspective view from below showing the mounting portion 64, and Figure 10 is an exploded perspective view showing the wire 65 detached from the first extension support portion 61. As shown in Figures 9(a) and (b), the mounting portion 64 includes a hook 702, a hook pivot shaft 706, a hook biasing member 703, a tray insertion portion 721, etc. The tray insertion portion 721 is an example of an insertion portion, and the extension unit 60 is attached to the manual feed unit 50 by inserting it into the mounting portion 54. In this embodiment, the tray insertion portion 721 has a width narrower than the manual feed unit 50 in the sheet width direction W. Therefore, damage to the exterior of the manual feed unit 50 can be suppressed when attaching or detaching the extension unit 60. Furthermore, in this embodiment, the first extension support portion 61 has a width narrower than the first sheet support portion 52 in the sheet width direction W. Therefore, when attaching or detaching the extension unit 60, damage to the exterior of the manual feeding unit 50 can be more effectively suppressed. Furthermore, in this embodiment, the second extension support portion 62 and the bent portion 63 have a narrower width than the first sheet support portion 52 in the sheet width direction W.

[0049] On the back side of the second sheet support portion 61a of the first extension support portion 61, two hook pivot shafts 706 are arranged symmetrically with respect to the sheet width direction W. A hook engagement portion 707 is formed at the upper end of each hook pivot shaft 706. A hook 702 is attached to each hook pivot shaft 706. The hook 702 has a hook pivot center hole 708 and is attached to the hook pivot shaft 706 so as to fit the hook pivot center hole 708 into it. The hook engagement portion 707 is formed to lock the hook 702 in the direction in which it would detach, so that the hook 702 can rotate freely with respect to the hook pivot shaft 706 but is attached in a way that prevents it from detaching upwards.

[0050] The hook biasing member 703 is made of a compression coil spring. The hook 702 has a biasing member positioning portion 709a that engages with the hook biasing member 703 to position it and prevent the hook biasing member 703 from shifting position more than necessary. On the side facing the biasing member positioning portion 709a in the sheet width direction W (the back surface of the second sheet support portion 61a), there is also a biasing member positioning portion 709b that engages with the hook biasing member 703 to position it. By installing the hook biasing member 703 between the opposing biasing member positioning portions 709a and 709b, which bias these to spread apart, the hook 702 is always biased by the hook biasing member 703. The hook biasing member 703 is an example of a biasing member and biases the hook 702 toward the closed position.

[0051] Next, the mounting configuration of the second extension support 62 and the cover 704 will be described. As shown in Figure 10, the cover 704 and the wire 65 are attached to the unit in which the first extension support 61, the hook 702, and the hook biasing member 703 (see Figure 9(a)) are assembled. The cover 704 is assembled to the first extension support 61 and is shaped so as not to obstruct the movement of the hook 702 and the hook biasing member 703, and is formed to completely cover the hook biasing member 703 so that the user cannot contact it from the outside. In this embodiment, the first extension support 61 and the cover 704 are fixed by fastening with screws, but this is not limited to this, and other methods such as engagement with engaging claws may also be used.

[0052] The wire 65 is a U-shaped linear member with an open end attached to the first extension support 61 on the downstream side in the sheet feeding direction Df. At the open end, it has two tip portions 65a that are bent inward toward each other in the sheet width direction W. The first extension support 61 has two support holes 710 that open outward on both sides in the sheet width direction W.

[0053] Each end 65a of the wire is inserted into a support hole 710 and positioned by being sandwiched vertically between a wire support base 711 and a wire retaining claw 712 formed on the first extension support portion 61. In addition, to prevent the second extension support portion 62 from shifting position relative to the sheet width direction W, a wire positioning wall 713 is formed on the first extension support portion 61, and the second extension support portion 62 is positioned by being sandwiched in the sheet width direction W as well. That is, the wire positioning wall 713 is an example of a retaining part and is located outside each support hole 710 in the sheet width direction. The two ends 65a of the wire 65 are inserted into each support hole 710 from the outside in the sheet width direction W and are fixed by the wire positioning wall 713, preventing them from coming out on the outside in the sheet width direction W. In this way, the position of the second extension support portion 62 is stabilized in the vertical direction and the sheet width direction W when transporting the long sheet SL.

[0054] Next, the operation of the hook 702 will be described using Figures 11 and 12. Figure 11 is a plan view showing the hook 702 in the closed position, and Figure 12 is a plan view showing the hook in the open position. The hook 702 is rotatably mounted on the first extension support portion 61 with the hook pivot axis 706 as the pivot center. The hook 702 has an outer stopper portion 714 and an inner stopper portion 715. The outer stopper portion 714 is provided so as to abut against the side wall portion of the first extension support portion 61, and the inner stopper portion 715 is provided so as to abut against the stopper wall 716 provided on the cover portion 704. The rotatable angle of the hook 702 is the angle until the outer stopper portion 714 and the inner stopper portion 715 abut against each other, and in this embodiment, it is set to approximately 20°.

[0055] In this embodiment, as shown in Figure 11, the closed position is when the outer stopper portion 714 abuts against the side wall portion of the first extension support portion 61, and as shown in Figure 12, the open position is when the inner stopper portion 715 abuts against the stopper wall 716 provided on the cover portion 704. That is, the hook 702 is an example of an engaging member and is displaceable between an engaging position (closed position) and a retracted position (open position) that is retracted from the engaging position (closed position).

[0056] The hook 702 has a switch portion 717 in a position accessible to the user. As shown in Figure 11, when the user is not pressing the switch portion 717, the biasing force of the hook biasing member 703 causes the outer stopper portion 714 to abut against the side wall of the first extension support portion 61, which is in a closed position. As shown in Figure 12, when the user pushes the switch portion 717 against the hook biasing member 703, the hook 702 rotates to an open position where the inner stopper portion 715 abuts against the stopper wall 716. In other words, the switch portion 717 is an example of an operating portion, and is operated to move the hook 702 towards the open position. When the user releases the switch portion 717 in this state, the biasing force of the hook biasing member 703 causes the hook 702 to rotate in the opposite direction and return to the closed position.

[0057] The biasing force of the hook biasing member 703 is set to, for example, 500gf each (1000gf total) in this embodiment, so that the extension unit 60 does not come off easily, but the user's operating force does not become so heavy that it impairs operability. Of course, the biasing force is not limited to this.

[0058] [Extension unit attachment / detachment configuration] Next, the details of attaching and detaching the extension unit 60 to the manual feed unit 50 will be explained using Figures 13(a) to 19. Figure 13(a) is a perspective view of the manual feed unit 50 as seen from the upstream side in the sheet feeding direction Df, i.e., from the extension unit 60 side, Figure 13(b) is a plan view, and Figure 13(c) is a cross-sectional view. The manual feed unit 50 is provided with a mounting portion 54 to which the mounting portion 64 of the extension unit 60 can be attached. That is, the mounting portion 54 is an example of an insertion opening and is provided at the upstream end in the sheet feeding direction Df. The mounting portion 54 can be located at any position as long as it is provided between the side regulating plates 53 in the sheet width direction W, but in this embodiment it is provided in the center in the sheet width direction W. This ensures the stability of the long sheet SL supported by the extension unit 60. Downstream of the mounting portion 54 in the sheet feeding direction Df, there is a guide rail 719 that restricts the position of the extension unit 60 in the sheet width direction W, and a hook engagement wall 720 which is an example of a mounting portion for engaging the hook 702. The hook engagement wall 720 is preferably positioned outside the guide rail 719 in the sheet width direction W so as not to hinder the attachment and detachment of the extension unit 60.

[0059] Furthermore, as shown in Figure 13(c), a vertical gap is provided between the tray insertion portion 721 and the cover portion 704 below it at the tip of the mounting portion 64. When mounting the mounting portion 64 to the mounting portion 54, the bottom plate portion 51a of the mounting portion 54 is inserted into the gap between the tray insertion portion 721 and the cover portion 704. This allows the mounting portion 64 and the mounting portion 54 to be positioned vertically. That is, the bottom plate portion 51a is an example of a lower member, positioned below the mounting portion 54, defining the lower part of the mounting portion 54, and forming the lower surface of the manual feed unit 50. The cover portion 704 is an example of a lower support portion, and when the tray insertion portion 721 is inserted into the mounting portion 54, the cover portion 704 sandwiches the bottom plate portion 51a between the tray insertion portion 721 and the cover portion 704 below the tray insertion portion 721. In this embodiment, the cover portion 704 has a narrower width than the first sheet support portion 52 in the sheet width direction W.

[0060] Figures 14 to 16 are plan views of the extension unit 60 being attached to the manual feed unit 50. As shown in Figure 14, the first extension support part 61 has a tray insertion part 721. The extension unit 60 is attached to the manual feed unit 50 by inserting the tray insertion part 721 into the mounting part 54 of the manual feed tray 51.

[0061] As shown in Figure 14, in order to attach the extension unit 60 to the manual feed unit 50, first the position of the tray insertion portion 721 of the extension unit 60 is aligned with the guide rail 719. The tray insertion portion 721 is restricted in the insertion direction by the guide rail 719, so that the extension unit 60 is inserted straight into the manual feed unit 50. As insertion progresses, as shown in Figure 15, the hook 702 comes into contact with the hook engagement wall 720. That is, the guide rail 719 is an example of a guide, and the manual feed unit 50 guides the tray insertion portion 721 inside the mounting portion 54. The guide rail 719 contacts and guides the inserted tray insertion portion 721 from both sides in the sheet width direction W, and also positions the tray insertion portion 721 in the sheet width direction W.

[0062] Here, if the hook engagement wall 720 and the hook 702 were parallel to each other along the sheet width direction W, the hook 702 would come into contact and lock, preventing further insertion. Therefore, in this embodiment, a hook inclined portion 722 is provided on the tip side of the claw portion of the hook 702 in the insertion direction. When the extension unit 60 is pushed in, the hook 702 rotates following the inclination of the hook inclined portion 722, and as shown in Figure 16, when the claw portion of the hook 702 overcomes the hook engagement wall 720, the hook biasing member 703 rotates the hook 702 in the opposite direction to the open position. As a result, the locking surface 723 on the claw portion of the hook 702, which faces opposite to the insertion direction, comes into contact with the hook engagement wall 720, returning the hook 702 to the closed position, and the extension unit 60 is attached to the manual feed tray 51. In other words, when the extension unit 60 is attached to the manual feed unit 50, the hook 702 is in the closed position, which engages with the hook engagement wall 720 and prevents the extension unit 60 from detaching from the manual feed unit 50.

[0063] Figures 17 to 19 are plan views of the extension unit 60 being detached from the manual feed unit 50. As shown in Figure 17, with the extension unit 60 attached to the manual feed unit 50, the user presses the switch portion 717 of the hook 702, causing the hook 702 to rotate in a direction that disengages the locking surface 723 from the hook engagement wall 720, and position it in the open position. While maintaining this state, the extension unit 60 is pulled out in a direction that detaches it from the manual feed tray 51, as shown in Figure 18. That is, the position of the hook 702 in the open position releases its engagement with the hook engagement wall 720, allowing the extension unit 60 to detach from the manual feed unit 50.

[0064] As shown in Figure 19, when the extension unit 60 is completely detached from the manual feed tray 51 and the pressure on the switch unit 717 is released, the hook biasing member 703 rotates the hook 702 in the opposite direction. As a result, the outer stopper portion 714 of the hook 702 abuts against the side wall of the first extension support portion 61, and the hook 702 returns to the closed position. With the configuration described above, the extension unit 60 can be made detachable from the manual feed unit 50.

[0065] In this embodiment, as shown in Figure 5(b), the maximum width over which the side regulating plate 53 of the manual feed unit 50 operates in the sheet width direction W is defined as the fifth distance L5, and the maximum width of the sheet support portion of the extension unit 60 is defined as the sixth distance L6. At this time, the fifth distance L5 > sixth distance L6. Specifically, the fifth distance L5 is set to approximately 320 mm, and the sixth distance L6 is set to approximately 150 mm. This reduces the contact area between the manual feed unit 50 and the extension unit 60, thereby preventing damage to the exterior of the manual feed unit 50 when attaching or detaching the extension unit 60.

[0066] Furthermore, in the sheet feeding direction Df, the length of the first sheet support portion 52 of the manual feed tray 51 is defined as the seventh distance L7, and the total length of the sheet support portion of the extension unit 60 is defined as the eighth distance L8. In this case, the seventh distance L7 < eighth distance L8. Specifically, the seventh distance L7 is approximately 280 mm, and the eighth distance L8 is 590 mm. With this configuration, a long sheet SL as shown in Figure 6(a) can be supported and fed, with a maximum sheet width of 320 mm and a sheet length of 1300 mm.

[0067] [Manual feed unit] Next, the manual feed unit 50 will be described using Figures 20 to 24(b). The manual feed unit 50 is provided with side restricting plates 53 for restricting the position of the sheet S in the sheet width direction W, each having a sheet restricting surface. Figure 20 is a perspective view showing the manual feed unit 50 before supporting the sheet S. The manual feed unit 50 has two holes 5a with the sheet width direction W as the longitudinal direction. The side restricting plates 53 are connected to a rack section 55 that is movable in the sheet width direction W on the back surface of the first sheet support section 52, passing through the holes 5a.

[0068] Figure 21 is a perspective view from below, illustrating the vicinity of the rack portion 55 on the back surface of the manual feed unit 50. A rack gear 516, which engages with the rack portion 55 of the side regulating plate 53, is rotatably supported on a gear support portion 5b provided on the back surface of the manual feed unit 50, thereby linking the movement of the two side regulating plates 53. A sheet width detection unit 519 is provided near the rack gear 516. The sheet width detection unit 519 is an example of a second detection unit and detects the length of the sheet in the sheet width direction W of the sheet supported by the first sheet support portion 52. The sheet width detection unit 519 includes a volume gear 517 and a volume sensor 518. The volume gear 517 meshes with the rack gear 516 and rotates synchronously. The volume gear 517 is supported by a shaft portion 518b provided on the volume sensor 518, which is held by the manual feed unit 50.

[0069] When the side regulating plate 53 is operated, the rack gear 516 rotates via the rack section 55, and the amount of rotation of the shaft section 518b, which rotates together with the volume gear 517 that rotates in sync with it, is detected by the volume sensor 518. A signal is transmitted from the volume sensor 518 to the control unit 100 via the volume sensor bundle 518c, thereby obtaining position information of the side regulating plate 53. That is, the volume sensor 518 is an example of a second detection unit, and by detecting the position of the pair of side regulating plates 53, it outputs the length of the sheet in the sheet width direction W of the sheet supported by the first sheet support section 52.

[0070] As shown in Figure 20, the manual feed unit 50 has a rear end detection unit 520. The rear end detection unit 520 is an example of a first detection unit and detects that the length of the sheet S supported by the first sheet support 52 in the sheet feeding direction Df is longer than a first length L11. Here, the first length L11 is, for example, the length of the sheet of the maximum standard size. As shown in Figure 22, the rear end detection unit 520 has a rear end detection flag 521 and a rear end flag sensor 522 that are rotatably supported by the manual feed unit 50. Figure 23(a) is a cross-sectional view of the rear end detection unit 520 when there is no sheet loading, viewed from direction B shown in Figure 20, and Figure 23(b) is a cross-sectional view of the rear end detection unit 520 when there is a sheet loading, viewed from direction B shown in Figure 20.

[0071] The rear end flag sensor 522 is an example of a flag member and is displaceable between a protruding position that protrudes upward from the first sheet support portion 52 and a retracted position that is retracted downward from the protruding position toward the first sheet support portion 52. As shown in Figure 23(a), the rear end detection flag 521 is rotatably supported by the flag holding portion 5c of the manual feed unit 50, with respect to the flag rotation axis 521a. The rear end detection flag 521 has a weight portion 521w on the side opposite to the sheet contact portion 521c with respect to the flag rotation axis 521a. In the state shown in Figure 20, when the sheet S is not supported by the manual feed unit 50, the rear end detection flag 521 is configured to rotate in the CW direction shown in Figure 22 due to the rotational moment caused by the weight of the weight portion 421w. That is, the weight portion 521w is an example of a biasing portion and biases the rear end detection flag 521 toward the protruding position.

[0072] In the state shown in Figure 23(a) where the sheet S is not supported, the contact portion 521b of the rear end detection flag 521 contacts the flag contact portion 5d of the manual feed unit 50, thereby maintaining the orientation of the rear end detection flag 521 (this state is called the protruding position). In this protruding position, the sheet contact portion 521c of the rear end detection flag 521 protrudes upward from the first sheet support portion 52 through the flag hole 5e provided in the manual feed unit 50.

[0073] Near the rear end detection flag 521, a rear end flag sensor 522 for detecting the detection unit 521d of the rear end detection flag 521 is held by the manual feed unit 50. The rear end flag sensor 522 is configured to detect the position of the rear end detection flag 521 by detecting whether light is blocked or transmitted by the detection unit 521d of the rear end detection flag 521. For example, in the state where the sheet S shown in Figure 23(a) is not supported, the rear end flag sensor 522 is in a transparent state.

[0074] As shown in Figure 23(b), when the sheet S is supported by the first sheet support 52, the sheet contact portion 521c of the rear end detection flag 521 is pushed down by the sheet S, causing the rear end detection flag 521 to rotate. This causes the detection unit 521d to shield the rear end flag sensor 522 from light. The signal detected by the rear end flag sensor 522 is transmitted to the control unit 100 via a bundle of wires (not shown), making it possible to determine the presence or absence of the sheet S at the rear end detection flag 521. The rear end flag sensor 522 is an example of the first detection unit, and outputs a detection result indicating whether the sheet length of the sheet supported by the first sheet support 52 is longer than the first length L11, depending on whether the rear end detection flag 521 is in a protruding position or a retracted position.

[0075] Figures 24(a) and (b) show the manual feed unit 40 viewed from the direction of arrow C in Figure 20, and illustrate the cases when an A4 size sheet and an A3 size sheet are supported on the first sheet support unit 52, respectively. The distance (L_SNS) from the position where the front end restricting unit 515 restricts the front end of the sheet, as shown in Figure 24(a), to the sheet contact portion 521c of the rear end detection flag 521 is 220 mm. Therefore, as shown in Figure 24(a), when an A4 size sheet S is supported, the rear end detection flag 521 remains in the protruding position, while the position information of the side restricting plate 53 reveals that the sheet width is 297.0 mm. From this combination, the control unit 100 can estimate that the standard size of the supported sheet S is A4 size.

[0076] In the state shown in Figure 24(b) with an A3-sized sheet S placed on it, the sheet length in the sheet feeding direction Df is longer than the distance (L_SNS) from the position where the front-end restricting part 515 restricts the front edge of the sheet to the sheet contact part 521c of the rear-end detection flag 521. Therefore, as shown in Figure 23(b), the supported sheet S pushes down the rear-end detection flag 521, and the rear-end flag sensor 522 is shielded from light by the detection part 521d. On the other hand, the position information of the side restricting plate 53 reveals that the sheet width is 297.0 mm. From this combination, the control unit 20 can estimate that the standard size of the placed sheet is A3 size.

[0077] [Pre-packing operation of standard sheets] The following describes the processing procedure for feeding a sheet S using the manual feed unit 40, using the flowchart shown in Figure 25. Figure 25 shows the processing procedure for a standard sheet from when a print job is input to the control unit 20 from the manual feed unit 40 until the transport operation begins (hereinafter also referred to as standard processing). The user inputs the size information of the sheet S to be used (referred to as "set size") by setting the print job from the host device 24 or by inputting using the device's operation unit 23 (S100). The control unit 20 receives the print job to be transported from the manual feed unit 40 or the input operation and performs sheet size detection (S101). The control unit 20 receives the detection results from each sensor, estimates the sheet size, and detects it as the detected size.

[0078] The control unit 20 determines whether the sheet width of the set size and the detected size match (S102). Here, the control unit 20 makes this determination based on whether the position information of the side regulating plate 53 obtained in the manual feed unit 50 matches the width information of the set size. If the control unit 20 determines that the sheet width of the set size and the detected size match (S102; YES), it determines whether the rear end flag sensor 522 is in the protruding position (S103). If the control unit 20 determines that the rear end flag sensor 522 is in the protruding position (S103; YES), it determines whether the length of the sheet feed direction Df of the set size (sheet length) is less than 220.0 mm (S104). If the control unit 20 determines that the sheet length of the set size is less than 220.0 mm (S104; YES), it starts the feed operation assuming that the set size and the detected size match (S105).

[0079] If the control unit 20 determines in S103 that the rear end flag sensor 522 is not in a protruding position (S103; NO), it determines whether the sheet length of the set size is 220.0 mm or more (S106). If the control unit 20 determines that the sheet length of the set size is 220.0 mm or more (S106; YES), it starts the feeding operation assuming that the set size and the detected size match (S105).

[0080] If the control unit 20 determines in S102 that the sheet width of the set size and the detected size do not match (S102; NO), it determines that the sheet size is mismatched and notifies the operation unit 23 of the mismatch (S107). Similarly, if the control unit 20 determines in S104 that the sheet length of the set size is not less than 220.0 mm (S104; NO), it determines that the sheet size is mismatched and notifies the operation unit 23 of the mismatch (S107). Similarly, if the control unit 20 determines in S106 that the sheet length of the set size is not 220.0 mm or more (S106; NO), it determines that the sheet size is mismatched and notifies the operation unit 23 of the mismatch (S107).

[0081] In this embodiment, the operation unit 23 is an example of a warning output unit, and outputs warnings via display or sound. Outputting a warning notification from the operation unit 23 is an example of mismatch processing by the control unit 20. Note that the warning output unit is not limited to the operation unit 23; for example, it may be an interface for outputting information to a host device 24 or other devices.

[0082] [Feeding operation for non-standard sized sheets] In the image forming apparatus 1 of this embodiment, the maximum standard sheet size that can be placed on the manual feed unit 50 is A3 size (sheet length 420.0 mm × sheet width 297.0 mm). Here, the sheet length in the sheet feeding direction Df for the maximum standard sheet size is defined as the first length L11. Note that although the first length L11 is defined as the sheet length of the maximum standard sheet size here, it is not limited to this and may be any standard sheet length.

[0083] On the other hand, irregularly sized sheets can also be transported by inputting a non-standard sheet size (irregular size) from the print job or the user via the operation unit 23, etc. Figure 26 shows a sheet S supported by the manual feed unit 50, and the supported sheet S is an irregularly sized sheet with a sheet length of 600.0 mm and a sheet width of 297.0 mm. The leading edge of the sheet S is supported by the leading edge regulating part 515 of the manual feed unit 50, but the rear end is not supported because it is larger than the manual feed unit 50, and hangs down from the upstream position in the transport direction. In this case, a sheet S with low rigidity may bend significantly upward on the manual feed unit 50. In this case, because the sheet S is bent, it does not come into contact with the sheet contact part 521c of the rear end detection flag 521, and the rear end detection flag 521 remains in the protruding position.

[0084] Next, the processing procedure, including the possibility of feeding a long sheet SL using the manual feed unit 40, will be explained using the flowchart shown in Figure 27. Figure 27 shows the processing procedure from when a print job from the manual feed unit 40 is input to the control unit 20 until the transport operation starts. Although the case where the extension unit 60 is not used is described here, the same processing may be performed when the extension unit 60 is used to feed a long sheet SL, for example, a sheet with a length of 900 mm or 1200 mm. In this case, the extension unit 60 supports a sheet S having a sheet length longer than the first length L11 together with the first sheet support unit 52. That is, when the extension unit 60 is mounted on the manual feed unit 50, it has a third sheet support unit 62a, which is an example of an upper sheet support unit that supports the long sheet SL above the first sheet support unit 52.

[0085] The user inputs the size information (set size) of the sheet S to be used (S200) through settings in the print job from the host device 24 or through input operations using the device's operation unit 23. The control unit 20 determines whether the sheet length of the set size is longer than the sheet length allowed for the maximum standard size (for example, 450.0 mm) (S201).

[0086] If the control unit 20 determines that the sheet length of the set size is longer than the sheet length allowed by the maximum standard size (S201; YES), it starts the feeding operation (S202). That is, if the sheet length of the set size is longer than the sheet length allowed by the maximum standard size, the sheet S may float as shown in Figure 26 and the rear end detection flag 521 may remain in the protruding position, and considering this, the control unit 20 starts feeding regardless of the position of the rear end detection flag 521. On the other hand, if the control unit 20 determines that the sheet length of the set size is not longer than the sheet length allowed by the maximum standard size (S201; NO), it proceeds to the standard processing shown in Figure 25 (S203).

[0087] In other words, the control unit 20 can perform mismatch processing when there is a mismatch between the detection result of the rear end detection unit 520 and the set sheet length of the sheet in the sheet information corresponding to the input manual feed unit 50. The control unit 20 does not perform mismatch processing if the set sheet length is shorter than the first length L11 (the sheet length of the maximum standard size) and the detection result of the rear end detection unit 520 matches the set sheet length. The control unit 20 also performs mismatch processing if the set sheet length is shorter than the first length L11 and the detection result of the rear end detection unit 520 does not match the set sheet length. Furthermore, the control unit 20 does not perform mismatch processing if the set sheet length is longer than the first length L11. This prevents false warnings from being issued when the set size and the detected size do not match, even when the set size and the detected size are mismatched, such as when the set size sheet length is longer than the sheet length allowed by the maximum standard size.

[0088] As described above, in the manual feeding unit 40 of this embodiment, the bent portion 63 is made continuous with the second extension support portion 62 in a state where it is bent upward relative to the first extension support portion 61. Furthermore, the first extension support portion 61 has a length that extends upstream beyond the upstream end of the standard sheet SN while the standard sheet SN is supported by the first sheet support portion 52 and the second sheet support portion 61a. As a result, even with the second extension support section 62 for the long sheet SL installed, the loading posture of the standard sheet SN is not affected, thus suppressing feeding problems of the standard sheet SN.

[0089] In this embodiment, the case in which the rear end detection flag 521 is placed in one location has been described, but this is not the only case, and multiple detection flags may be placed. Also, in this embodiment, an example is shown in Figure 27 in which the operation is changed when the user-specified size information exceeds the length allowed by the maximum standard size, but this is not the only case. For example, a function may be set to selectively switch between the operation shown in Figure 25 and the operation shown in Figure 27, and a service technician may selectively enable this function by changing the device settings.

[0090] <Other Embodiments> In the embodiment described above, as shown in Figure 27, the control unit 20 determines whether the sheet length of the set size is longer than the sheet length allowed for the maximum standard size (e.g., 450.0 mm) after setting the set size (S201). However, it is not limited to this, and for example, the matching of the sheet width between the set size and the detected size may be determined before performing the S201 process. The processing procedure in this case is shown in Figure 28. Although the case without using the extension unit 60 is described here, the same processing may be performed even when the extension unit 60 is used.

[0091] Figure 28 shows the processing procedure from when a print job is input to the control unit 20 from the manual feed unit 40 until the transport operation begins. The user inputs the size information (set size) of the sheet S to be used (S300) through settings in the print job from the host device 24 or through input operations using the device's operation unit 23. The control unit 20 receives the print job to be transported from the manual feed unit 40 or the input operation and performs sheet size detection (S301). The control unit 20 receives the detection results from each sensor, estimates the sheet size, and detects it as the detected size.

[0092] The control unit 20 determines whether the sheet width of the set size and the detected size match (S302). Here, the control unit 20 makes this determination based on whether the position information of the side regulating plate 53 obtained in the manual feed unit 50 matches the width information of the set size. If the control unit 20 determines that the sheet width of the set size and the detected size match (S302; YES), it executes S201 to S203 shown in Figure 27. If the control unit 20 determines that the sheet width of the set size and the detected size do not match (S302; NO), it determines that the sheet sizes do not match and warns the operation unit 23 of the mismatch (S303).

[0093] In other words, the control unit 20 can perform mismatch processing when the detection result of the sheet width detection unit 519 and the set sheet width of the sheet in the sheet information corresponding to the input manual feed unit 50 do not match. The control unit 20 performs mismatch processing if the detection result of the sheet width detection unit 519 and the set sheet width do not match. The control unit 20 does not perform mismatch processing if the detection result of the sheet width detection unit 519 and the set sheet width match, and the set sheet length is shorter than the first length L11, and the detection result of the rear end detection unit 520 and the set sheet length match. The control unit 20 also performs mismatch processing if the detection result of the sheet width detection unit 519 and the set sheet width match, and the set sheet length is shorter than the first length L11, and the detection result of the rear end detection unit 520 and the set sheet length do not match. Furthermore, if the detection result of the sheet width detection unit 519 matches the set sheet width, and the set sheet length is longer than the first length L11, the control unit 20 does not perform the mismatch processing.

[0094] According to this processing procedure, the sheet width is checked for match before determining whether or not it is a long sheet in S201, and a warning is issued if the sheet width does not match. Therefore, compared to determining whether a standard sheet is not a long sheet and then checking for sheet width match in the standard processing, this method enables faster processing. [Explanation of symbols]

[0095] 1…Image forming apparatus, 40…Manual feed unit (sheet feeder), 41…Feeding unit, 50…Manual feed unit (sheet support unit), 52…First sheet support unit, 60…Extension unit (extension support unit), 61…First extension support unit, 61a…Second sheet support unit, 62…Second extension support unit, 62a…Third sheet support unit, 62b…Upper end, 63…Bending unit, 201B…Image forming unit, 515…Tip regulating unit, L1…First distance, L2…Second distance, L3…Third distance, L4…Fourth distance, S sheet

Claims

1. A sheet support unit having a first sheet support portion that supports the sheet, A feeding unit that feeds the sheet supported by the first sheet support unit in the sheet feeding direction, The system includes an extension support unit which is detachably attached to the sheet support unit and, when attached to the sheet support unit, is located upstream of the first sheet support portion in the sheet feeding direction and supports the sheet, When the extension support unit is attached to the seat support unit, A first extension support portion having a second sheet support portion that extends upstream from the first sheet support portion in the sheet feeding direction, A second extension support section having a third sheet support section positioned upstream of the second sheet support section in the sheet feeding direction and supporting a long sheet together with the first sheet support section and the second sheet support section, The second extension support portion has a bent portion that is bent upward relative to the first extension support portion and continuous with it, The first extension support portion has a length that extends upstream of the upstream end of a standard-sized sheet, while the sheet is supported by the first and second sheet support portions in the sheet feeding direction. A sheet feeding device characterized by the following features.

2. The aforementioned standard-sized sheet is the longest standard-sized sheet among several types of standard-sized sheets, having the longest sheet length in the sheet feeding direction. The sheet feeding device according to feature 1.

3. The bent portion is positioned upstream of the upstream end of the standard-sized sheet in the sheet feeding direction when the standard-sized sheet is supported by the first sheet support portion and the second sheet support portion. The sheet feeding device according to feature 1.

4. The bent portion is located below the second seat support portion. The sheet feeding device according to feature 1.

5. The first sheet support portion forms a first support surface that contacts and supports the sheet. The second sheet support portion forms a second support surface that contacts and supports the sheet. The second support surface is arranged on the same plane as the first support surface. The sheet feeding device according to feature 1.

6. The extension support unit is formed to be narrower in the width direction than the sheet width of the largest standard-size sheet, which has the widest sheet width in the width direction perpendicular to the sheet feeding direction among multiple types of standard-size sheets. The sheet feeding device according to feature 1.

7. The sheet feeding direction includes a front-end restricting portion that is positioned downstream of the first sheet support portion and is displaceable between a contact position that abuts the downstream end of the sheet supported by the first sheet support portion in the sheet feeding direction, and an allowable position that retracts from the contact position to allow feeding of the sheet supported by the first sheet support portion. The tip regulating portion is located in the contact position when not feeding and in the allowable position when feeding. The sheet feeding device according to feature 1.

8. The first distance in the sheet feeding direction between the tip restricting portion located at the aforementioned contact position and the upstream end of the first extension support portion is longer than the second distance in the sheet feeding direction for a standard-sized sheet. The sheet feeding device according to feature 7.

9. The third distance in the sheet feeding direction between the tip restricting portion and the bent portion located at the aforementioned contact position is longer than the fourth distance from the bent portion to the uppermost end of the second extension support portion. The sheet feeding device according to feature 7.

10. When the distance between the tip restricting portion and the bending portion located at the aforementioned contact position in the sheet feeding direction is defined as the third distance, and the distance from the bending portion to the uppermost end of the second extension support portion is defined as the fourth distance, If the sheet length in the sheet feeding direction of the sheet supported by the first sheet support, the second sheet support, and the third sheet support is longer than the sum of the third distance and the fourth distance, the portion of the sheet upstream in the sheet feeding direction from the portion supported by the third sheet support is supported by hanging down from the uppermost end of the second extension support. The sheet feeding device according to feature 7.

11. A sheet feeding device according to any one of claims 1 to 10, It comprises an image forming unit that forms an image on a sheet, An image forming apparatus characterized by the following features.

12. An extension support unit that is detachably attached to a sheet support unit having a first sheet support portion that supports a sheet, and in the attached state on the sheet support unit, is located upstream of the first sheet support portion in the sheet feeding direction by the feeding portion and supports the sheet, A first extension support portion having a second sheet support portion that extends upstream from the first sheet support portion in the sheet feeding direction, A second extension support section is located upstream of the second sheet support section in the sheet feeding direction and has a third sheet support section that supports a long sheet together with the first sheet support section and the second sheet support section, The second extension support portion is further comprising a bent portion that connects the first extension support portion to the second extension support portion in an upwardly bent state, The first extension support portion has a length that extends upstream of the upstream end of a standard-sized sheet, while the sheet is supported by the first and second sheet support portions in the sheet feeding direction. An extension support unit characterized by the following features.

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