Sheet feeding device, manual feed tray device, document feeding device and image forming apparatus

Abstract

To provide a sheet feeding device, a manual insertion tray device, a document feeding device and an image forming device capable of suppressing erroneous detection of a sheet size detection part even if deformation of a sheet occurs and reducing the thickness of the entire sheet placement tray.SOLUTION: A sheet feeding device 201 includes: a sheet placement tray 210 on which a sheet (G) is placed; and a sheet size detection part 220 arranged on the sheet placement tray 210 and detecting the size of the sheet (G) placed on the sheet placement tray 210, wherein an upper surface 210a of the sheet placement tray 210 includes: a first upper surface area α1 including a detection part γ for detecting the sheet (G) of the sheet size detection part 220; and a second upper surface area α2 other than the first upper surface area α1. The first upper surface area α1 is formed in a convex shape so as to be higher than the second upper surface area α2.SELECTED DRAWING: Figure 3A

Description

[Technical Field]

[0001] The present invention relates to a sheet feeding device, a manual feed tray device, a document feeding device, and an image forming apparatus such as a copying machine, a multifunction machine, a printer, or a facsimile machine. [Background technology]

[0002] A sheet supplying device equipped with a sheet loading tray on which sheets such as recording paper and documents are placed is usually provided with a sheet size detecting unit disposed on the sheet loading tray to detect the size of the sheets placed on the sheet loading tray (see Patent Document 1).Here, the sheet supplying device is provided, for example, in a manual feed tray device that is openably and closably provided on the side of the image forming apparatus main body, or in a document feeding device that transports documents to a document reading position.

[0003] In such a sheet feeder, the upper surface of the sheet loading tray is often formed as a uniform plane (or a nearly flat plane). In this case, deformation of the sheet (for example, Z-folding of the sheet or curling of the sheet) causes the detected portion of the sheet to move away from the sheet size detection unit, which may result in false detection by the sheet size detection unit depending on the degree of deformation of the sheet.

[0004] Furthermore, in order to arrange the sheet size detection unit on the sheet loading tray, a certain amount of space (thickness of the sheet loading tray) is required on the sheet loading tray, and if the top surface of the sheet loading tray is formed as a uniform plane (or approximately plane), the thickness of the entire sheet loading tray tends to become thick. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-301457 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, the present invention aims to provide a sheet supplying device, a manual feed tray device, a document feeding device, and an image forming device that can suppress erroneous detection by the sheet size detection unit even if deformation of the sheet occurs, and can reduce the thickness of the entire sheet loading tray. [Means for solving the problem]

[0007] In order to solve the above problem, the sheet feeding device of the present invention is a sheet feeding device including a sheet loading tray on which sheets are loaded, and a sheet size detection unit disposed on the sheet loading tray and detecting the size of the sheet loaded on the sheet loading tray, wherein the upper surface of the sheet loading tray has a first upper surface area including a detection portion of the sheet size detection unit that detects the sheet, and a second upper surface area other than the first upper surface area, and the first upper surface area is formed in a convex shape so as to be higher than the second upper surface area, The convex shape includes a curved surface, and the convexly formed surface is composed of a plurality of surfaces, each of which includes a convexly curved surface, and the plurality of convexly curved surfaces have different radii of curvature, and the individual curved surfaces having the radii of curvature are combined and connected along the sheet feeding direction, and are connected to each other to form a smooth curved surface shape as a whole. It is characterized by:

[0008] A manual feed tray device according to the present invention is characterized by including the sheet supply device according to the present invention.

[0009] Further, a document feeding device according to the present invention is characterized by including the sheet supplying device according to the present invention.

[0010] An image forming apparatus according to the present invention is characterized by including the manual feed tray device according to the present invention and / or the document feeder according to the present invention. [Effects of the Invention]

[0011] According to the present invention, even if a sheet is deformed, it is possible to suppress erroneous detection by the sheet size detection unit, and also to reduce the thickness of the entire sheet loading tray. [Brief explanation of the drawings]

[0012] [Figure 1]1 is a perspective view showing an external appearance of an image forming apparatus according to an embodiment of the present invention; [Figure 2] 1 is a perspective view of the front side of a document feeder according to an embodiment of the present invention, viewed obliquely from above; [Figure 3A] FIG. 2 is a perspective view of a sheet placement tray in the document feeder, viewed obliquely from above on the front side. [Figure 3B] FIG. 2 is a perspective view of a sheet placement tray in the document feeder, viewed obliquely from above on the rear side. [Figure 4A] FIG. 2 is a plan view showing a second tray portion of the sheet placement tray. [Figure 4B] 10 is a plan view showing a first upper surface area provided in a second tray portion of the sheet loading tray. FIG. [Figure 5A] 3 is an enlarged perspective view showing a first upper surface area portion on the upper surface of the sheet loading tray. FIG. [Figure 5B] 10 is an enlarged side view showing a first upper surface area portion on the upper surface of the sheet loading tray. FIG. [Figure 6A] 10 is a cross-sectional view showing a state in which both the first sheet size detection section and the second sheet size detection section in the first upper surface area detect the absence of a sheet. FIG. [Figure 6B] 10 is a cross-sectional view showing a state in which both a first sheet size detection unit and a second sheet size detection unit in the first upper surface area detect the presence of a sheet. FIG. [Figure 7A] FIG. 2 is a perspective view showing a sheet size detection unit. [Figure 7B] FIG. 2 is a perspective view showing an actuator that configures a sheet size detection unit. [Figure 8] 10 is a plan view showing another example of the shape of the first upper surface region when viewed from above. FIG. [Figure 9] FIG. 10 is a plan view showing still another example of the shape of the first upper surface region when viewed from above. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. The names and functions of these components are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0014] 1 is a perspective view showing the appearance of an image forming apparatus 100 according to an embodiment of the present invention. The front side (front side, operation side) in the depth direction X of the image forming apparatus 100 is designated by the symbol X1, and the rear side (rear side, back side) is designated by the symbol X2. In the left-right direction Y, which is orthogonal to both the depth direction X and the up-down direction Z of the image forming apparatus 100, one side (right side) is designated by the symbol Y1, and the other side (left side) is designated by the symbol Y2. The upper side in the up-down direction Z is designated by the symbol Z1, and the lower side is designated by the symbol Z2.

[0015] Image forming apparatus 100 is a multifunction peripheral having a copy function, a scanner function, a facsimile function, and a printer function. Image forming apparatus 100 includes an image forming apparatus main body 110, a document feeder 200 having a sheet feeder 201, and a manual feed tray device 120. Image forming apparatus main body 110 includes an image reading device 111, a paper feeder 112, an image forming unit 113, and a discharge unit 114. Manual feed tray device 120 is provided on a side surface of image forming apparatus main body 110 (the side surface as viewed from the front side X1) so as to be openable and closable.

[0016] The image reading device 111 reads an image of a document and has a document reading unit (scanner) not shown. The image reading device 111 reads an image of the document using the document reading unit while the document is being transported by the document feeder 200, or scans and reads a document placed on a document placing table of the document reading unit using the document reading unit.

[0017] The document feeder 200 is supported so as to be openable and closable relative to the image forming apparatus main body 110. When the document feeder 200 is opened relative to the image forming apparatus main body 110, the document placing table of the image forming apparatus 100 is opened, and a document can be placed thereon manually.

[0018] The paper feeder 112 stores sheets such as recording paper and supplies the stored sheets toward the image forming unit 113. The paper feeder 112 supplies sheets of each size using the center as a reference (center reference) in the width direction W perpendicular to the supply direction H. The image forming unit 113 forms (prints) an image on the sheet sent from the paper feeder 112 based on image data. The discharge unit 114 discharges the sheet on which the image has been formed by the image forming unit 113.

[0019] [First embodiment] FIG. 2 is a perspective view of the front side X1 of the document feeder 200 according to the embodiment of the present invention, viewed from diagonally above. FIGS. 3A and 3B are perspective views of the sheet loading tray 210 of the document feeder 200, viewed from diagonally above the front side X1 and the rear side X2, respectively. FIG. 4A is a plan view showing the second tray portion 212 of the sheet loading tray 210. FIG. 4B is a plan view showing a first upper surface area α1 provided in the second tray portion 212 of the sheet loading tray 210. FIGS. 5A and 5B are a perspective view and a side view, respectively, showing an enlarged view of the first upper surface area α1 of the upper surface 210a of the sheet loading tray 210. FIGS. 6A and 6B are cross-sectional views showing the first sheet size detection unit 220a and the second sheet size detection unit 220b in the first upper surface area α1 detecting the absence (OFF) and presence (ON) of a sheet (document G), respectively. 7A is a perspective view showing the sheet size detection unit 220. FIG. 7B is a perspective view showing an actuator 222 that constitutes the sheet size detection unit 220.

[0020] In this embodiment, the sheet supply device 201 includes a sheet loading tray 210 on which sheets (documents G in this example) are loaded, and a sheet size detection unit 220 (document size detection unit) disposed on the sheet loading tray 210 and detecting the size of the sheets (G) loaded on the sheet loading tray 210. The sheet supply device 201 supplies sheets (G) of each size with the center in a width direction W perpendicular to the supply direction H as a reference (center reference).

[0021] Examples of sheet size detection units include those having an actuator that contacts the sheet (G) and rotates around a rotation axis along a transverse direction V that intersects with the sheet (G) supply direction H, and those having a light-reflection sensor equipped with a light-emitting unit and a light-receiving unit that detects the presence or absence of the sheet (G) by irradiating the sheet (G) with light emitted by the light-emitting unit and receiving light reflected from the sheet (G) with the light-receiving unit. A sheet size detection unit having an actuator may, for example, have one upper end of the actuator as the contact portion with the sheet (G) and the other lower end of the actuator as the actuated portion that actuates the actuating portion of the switch unit. Examples of switch units include a light-transmitting sensor switch that detects the interruption of light by the actuated portion of the actuator, a reed switch that detects the presence or absence of a magnetic field by providing a permanent magnet in the actuated portion of the actuator, and a mechanical microswitch that forms an actuator using a lever.

[0022] In this embodiment, the sheet size detection unit 220 is made up of multiple sheet size detection units. Specifically, the multiple sheet size detection units 220 detect the size of the sheet (G) in the supply direction H. In this example, the multiple sheet size detection units include a first sheet size detection unit 220a and a second sheet size detection unit 220b. Note that the first sheet size detection unit 220a and the second sheet size detection unit 220b have the same configuration, and are therefore shown as a single diagram in FIGS. 7A and 7B.

[0023] The first sheet size detection unit 220a and the second sheet size detection unit 220b detect the presence or absence of a sheet (G). The first sheet size detection unit 220a and the second sheet size detection unit 220b are electrically connected to an input system of the control unit (not shown). The control unit can detect the feed direction size of the sheet (G) in the feed direction H (e.g., A3 portrait, B4 portrait, A4 portrait, B5 portrait, A4 landscape, B5 landscape, etc.) by combining the on / off states of the first sheet size detection unit 220a and the second sheet size detection unit 220b.

[0024] 7A and 7B, the sheet size detection unit 220 (220a, 220b) has an actuator 222 that contacts the sheet (G) and rotates about a rotation axis β (rotation shaft 221) along a transverse direction V that intersects with the supply direction H of the sheet (G). In the sheet size detection unit 220, one upper end of the actuator 222 can be configured as a contact portion 222a that contacts the sheet (G), and the other lower end of the contact portion 222a can be configured as an actuated portion 222b that actuates an actuating portion 223a of the switch unit 223. A through-hole 212a that penetrates the contact portion 222a of the actuator 222 in the up-down direction Z is provided in the upper surface 210a (second tray portion 212) of the sheet loading tray 210. The through-hole 212a is slightly larger (by a predetermined dimension) than the size of the abutment portion 222a so that the abutment portion 222a can be inserted through the through-hole 212a by rotation of the actuator 222 about the rotation axis β. In addition, a weight member 224 is provided on the opposite side of the actuator 222 from the abutment portion 222a across the rotation axis β. In this way, by providing the weight member 224 on the actuator 222, the abutment portion 222a of the actuator 222 can be reliably caused to protrude from the through-hole 212a, and thereby the operating portion 223a of the switch portion 223 can be reliably operated (turned off in this example). When the contact portion 222a of the weight member 224 is not in contact with the sheet (G), the contact portion 222a protrudes from the upper surface 210a through the through-hole 212a, whereas when the contact portion 222a is in contact with the sheet (G), the weight member 224 has such a weight that the actuator 222 rotates and the contact portion 222a retreats into the sheet loading tray 210. In this example, the switch portion 223 is a light-transmitting sensor switch that detects the transmission and blocking of light L by the actuated portion 222b of the actuator 222. More specifically, the actuating portion 223a is composed of a light-emitting portion 223a1 and a light-receiving portion 223a2. The light-emitting portion 223a1 emits light toward the light-receiving portion 223a2. The light-receiving portion 223a2 receives the light L from the light-emitting portion 223a1. When the contact portion 222a of the actuator 222 is not in contact with the sheet (G), the actuated portion 222b blocks the light L directed from the light emitting portion 223a1 to the light receiving portion 223a2.On the other hand, when the contact portion 222a of the actuator 222 is in contact with the sheet (G), the actuated portion 222b allows the light L to pass from the light emitting portion 223a1 to the light receiving portion 223a2.

[0025] As shown in FIGS. 3A to 6B, the upper surface 210a of the sheet loading tray 210 has a first upper surface area α1 including a detection portion γ (γa, γb) (see FIGS. 4B and 5B) that detects the sheet (G) of the sheet size detection unit 220 (220a, 220b), and a second upper surface area α2 other than the first upper surface area α1. The first upper surface area α1 is formed in a convex shape so as to be higher than the second upper surface area α2. In this example, the detection portion that detects the sheet (G) of the sheet size detection unit 220 is the portion where the actuator 222 comes into contact with at least the sheet (G).

[0026] According to this embodiment, the first upper surface region α1 is formed in a convex shape so as to be higher than the second upper surface region α2, thereby increasing the height at which the sheet (G) can be detected by the sheet size detection unit 220 (220a, 220b). Therefore, even if the sheet (G) is deformed (e.g., a Z-shaped fold or curl), the detection margin for the deformed sheet (G) can be increased. In other words, the detected portion of the sheet (G) is less likely to separate from the sheet size detection unit 220, thereby reducing false detection by the sheet size detection unit 220. Furthermore, because only a portion of the upper surface 210a of the sheet loading tray 210 is formed in a convex shape, the overall thickness of the sheet loading tray 210 can be reduced. Therefore, the sheet feeding device 201 can be made thinner. Furthermore, because only a portion of the upper surface 210a of the sheet loading tray 210 is formed in a convex shape, the ease of removing sheets (especially documents G) from the sheet loading tray 210 can be improved. Here, the higher the height of the first upper surface area α1, the more effective it is in suppressing false detection by the sheet size detection unit 220 and improving the ease of removing the sheet (G).

[0027] Incidentally, the sheet size detection unit 220 (220a, 220b) having the actuator 222 as in this embodiment is easily prone to erroneous detection because it is activated when the actuator 222 comes into contact with the sheet (G).

[0028] In this regard, in the present embodiment, the first upper surface region α1 is formed in a convex shape so that it is higher than the second upper surface region α2, so that even if the sheet size detection unit 220 has an actuator 222, erroneous detection by the sheet size detection unit 220 can be suppressed.

[0029] The convex shape may be a square shape, but in this case, unnecessary space for providing the sheet size detection unit 220 is likely to be generated.

[0030] In this regard, in the present embodiment, the convex shape includes a curved shape, which reduces the number of angular portions and thereby reduces the space that is not required for providing the sheet size detection unit 220.

[0031] In this embodiment, the convex surface is made up of multiple surfaces, which allows the individual surfaces of the convex surface to be easily combined, thereby enabling the convex shape of the first upper surface region α1 to be flexibly formed according to the size and shape of the sheet size detection unit 220.

[0032] In this embodiment, the multiple surfaces include multiple convex curved surfaces α1(1) to α1(n) (n is an integer of 2 or more, n=6 in this example) (see FIGS. 5A and 5B). This allows the first upper surface region α1 to have a smooth shape, and reduces the step between the second upper surface region α2 and the first upper surface region α1. This accordingly improves the detectability of the sheet size detection unit 220 (220a, 220b) for the sheet (G), and also improves the ease with which sheets (especially document G) can be removed from the sheet placement tray 210.

[0033] In this example, the multiple convex curved surfaces α1(1) to α1(n) have different radii of curvature, and are connected to each other to form a smooth curved surface overall.

[0034] In this embodiment, the plurality of convex curved surfaces α1(1) to α1(n) are connected together along the feeding direction H of the sheet (G).

[0035] Do this child As a result, it is possible to form a smooth curved shape along the feeding direction H of the sheet (G), thereby improving the design of the sheet placement tray 210 and the ease of taking out the sheet (G).

[0036] In this embodiment, as shown in Figures 3A and 3B, the upstream region α2b of the second upper surface region α2, from the upstream end α1a of the first upper surface region α1 to the upstream end α2a of the second upper surface region α2 in the supply direction H of the sheet (G), is lower than the first upper surface region α1.

[0037] This improves the ease of taking out sheets (especially documents G) onto the sheet placement tray 210 on the upstream side of the second upper surface area α2 relative to the first upper surface area α1 in the supply direction H of the sheets (G).

[0038] In this embodiment, the first upper surface region α1 is formed so that the apex Q (see FIG. 5B) of the convex shape is located at the center of the sheet (G) in the supply direction H. Here, the concept of the center not only refers to a position (center position) halfway along the supply direction H of the first upper surface region α1, but also includes a position near the center within a predetermined range in the supply direction H that includes the center position of the first upper surface region α1. The height of the apex Q from the second upper surface region α2 is not limited to this, but can be exemplified as approximately 3 mm to 10 mm. In this example, the height of the apex Q from the second upper surface region α2 is approximately 3 mm.

[0039] This allows the sheet (G) to be reliably aligned from the center to the upstream and downstream sides in the convex supply direction H, thereby improving the detectability of the sheet size detection unit 220 (220a, 220b) for the sheet (G) and improving the ease of removal onto the sheet loading tray.

[0040] In this embodiment, the sheet loading tray 210 includes a first tray portion 211 and a second tray portion 212 connected to the first tray portion 211 and located upstream of the first tray portion 211 in the sheet (G) supply direction H. In this case, if the sheet size detection portion 220 (220a, 220b) is provided in the first tray portion 211 downstream of the second tray portion 212 in the sheet supply direction H, size detection by the sheet size detection portion 220 is likely to be restricted.

[0041] In this regard, in the present embodiment, the first upper surface area α1 is provided in the second tray portion 212. This allows the sheet size detection unit 220 to be provided in the second tray portion 212, which is upstream of the first tray portion 211 in the supply direction H, and thereby makes it possible to reduce restrictions on size detection by the sheet size detection unit 220.

[0042] If the area of ​​the first upper surface area α1 relative to the area of ​​the upper surface 210a of the second tray section 212 is too large, the proportion of the area of ​​the upper surface 210a of the second tray section 212 that is occupied by the first upper surface area α1, which is higher than the second upper surface area α2, increases accordingly, which increases the overall thickness of the sheet loading tray 210 and makes it difficult to achieve a thin overall sheet supply device 201.

[0043] In this embodiment, when the area of ​​the second tray portion 212 is Sa and the area of ​​the first upper surface area α1 is Sb, the relationship (Sa-Sb)>Sb is satisfied. That is, the area Sb of the first upper surface area α1 may be smaller than ½, ⅓, ¼, or ⅕ of the area Sa of the second tray portion 212 (the first upper surface area α1 and the second upper surface area α2). The area Sb of the first upper surface area α1 can be appropriately set depending on the size and arrangement of the sheet size detection unit 220 (220a, 220b). For example, the area Sb can be set to an area that ensures a minimum space for providing the sheet size detection unit 220.

[0044] By doing so, the proportion of the first upper surface area α1 to the area of ​​the upper surface 210a of the second tray section 212 can be reduced, thereby reducing the thickness of the entire sheet loading tray 210 and making the entire sheet supply device 201 thinner.

[0045] In this embodiment, the first upper surface area α1 is provided in the supply direction (H) of the sheets (G) and in the center of the width direction W perpendicular to the supply direction (H) of the sheets (G) in the second tray section 212. Here, the concept of the center includes not only the position where the position (center position) of half the maximum distance in the width direction W of the first upper surface area α1 coincides with the position (center position) of half the maximum distance in the width direction W of the second tray section 212, but also the vicinity of the center position where the center position in the width direction W of the first upper surface area α1 falls within a predetermined range in the width direction W including the center position of the second tray section 212.

[0046] In this way, by locating the first upper surface area α1 in the center of the second tray section 212 in the supply direction H and width direction W of the sheet (G), it is possible to further improve the size detection by the sheet size detection section 220 (220a, 220b) and the ease of removing the sheet (especially the document G) to the sheet loading tray 210.

[0047] 5A, the second upper surface region α2 is flat. The first upper surface region α1 has an upstream end α1a in the sheet (G) supply direction H that is flush with the flat second upper surface region α2, gradually increasing in height from the upstream end α1a to the apex Q, and gradually decreasing from the apex Q to the downstream end α1b in the sheet (G) supply direction H, with the downstream end α1b being flush with the second upper surface region α2. Here, "same height as the second upper surface region α2" not only means exactly the same height as the second upper surface region α2, but also encompasses an approximately same height that is substantially the same height as the second upper surface region α2, taking into account variations in components, mounting errors during manufacturing, and the like.

[0048] By doing so, the step between the second upper surface region α2 and the first upper surface region α1 can be eliminated or almost eliminated, and the second upper surface region α2 and the first upper surface region α1 on the upper surface 210a can be made to have a smooth shape.

[0049] Incidentally, if the number of different sizes of the sheets (G) increases, it is necessary to provide a plurality of sheet size detection units 220.

[0050] In this regard, in the present embodiment, a plurality of sheet size detection units 220 are arranged side by side along the sheet (G) supply direction H. The first upper surface region α1 includes detection portions (γa, γb) of the plurality of sheet size detection units (220a, 220b) that detect the sheet (G).

[0051] In this way, by arranging a plurality of sheet size detection units 220 (220a, 220b) side by side along the sheet (G) supply direction H, it is possible to detect the size types of the sheets (G) even if the number of different sizes of the sheets (G) increases. Moreover, by including detection portions (γa, γb) that detect the sheets (G) of the plurality of sheet size detection units (220a, 220b) in the first upper surface region α1, it is possible to suppress erroneous detection by the plurality of sheet size detection units (220a, 220b) and reduce the overall thickness of the sheet loading tray 210.

[0052] In this embodiment, the first upper surface region α1 is formed in a trapezoidal shape when viewed from above (top). Specifically, the trapezoid shape of the first upper surface region α1 is an isosceles trapezoid extending in the supply direction H of the sheet (G), with the upstream side being the upper base and the downstream side being the lower base. In this example, as shown in Fig. 4B, the first upper surface region α1 is formed in a shape in which the distance d1 of the upper base is smaller than the distance d2 of the lower base, and the height h is greater than the distance d1 of the upper base and the distance d2 of the lower base.

[0053] [Second embodiment] FIG. 8 is a plan view showing another example of the shape of the first upper surface region α1 as viewed from above.

[0054] In the first embodiment, the shape of the first upper surface region α1 in a plan view is trapezoidal, but in the second embodiment, the shape of the first upper surface region α1 in a plan view is a shape consisting of an elliptical arc portion α1c and a linear portion α1d connecting both ends of the elliptical arc portion α1c. In this example, the first upper surface region α1 is formed in a shape such that the distance d3 of the elliptical arc portion α1c in the supply direction H is greater than the distance d4 of the linear portion α1d.

[0055] The second embodiment can also have the same configuration and effects as the first embodiment, except for the shape of the first upper surface region α1 when viewed from above.

[0056] [Third embodiment] FIG. 9 is a plan view showing still another example of the shape of the first upper surface region α1 as viewed from above.

[0057] In the third embodiment, the shape of the first upper surface region α1 is an ellipse extending in the supply direction H when viewed from above.

[0058] The second embodiment can also have the same configuration and effects as the first embodiment, except for the shape of the first upper surface region α1 when viewed from above.

[0059] [Other embodiments] In the first to third embodiments, the sheet size detection unit 220 detects the size of the sheet (G) in the supply direction H, but it may also detect the size of the sheet in the width direction W perpendicular to the supply direction H. In this case, it can correspond to a sheet size detection unit that detects the size in the width direction W.

[0060] Furthermore, in the first to third embodiments, the first upper surface area α1 is provided in the center of the second tray portion 212 in the width direction W, but it may be provided on one side (front side X1) or the other side (rear side X2) in the width direction W. This is particularly effective when the sheet feeding device feeds sheets of various sizes based on one side or the other side in the width direction W perpendicular to the feeding direction H.

[0061] Furthermore, in the first to third embodiments, the sheets are documents G and the sheet supply device 201 is provided in the document feed device 200, but the sheets may be recording materials such as recording paper, and the sheet supply device 201 may be provided in a manual feed tray device 120 that is openably and closably provided on the side (side as viewed from the front side X1) of the image forming apparatus main body 110.

[0062] Furthermore, in the first to third embodiments, the sheet size detection unit 220 has an actuator 222, but it may also have a light reflection sensor equipped with a light emitting unit and a light receiving unit. In this case, the detection portion of the sheet size detection unit that detects the sheet (G) can be a light passing portion (opening) that passes light emitted from the light emitting unit and passes light reflected from the sheet (G), or the light emitting element portion (sensor portion) of the light emitting unit and the light receiving element portion (sensor portion) of the light receiving unit themselves.

[0063] The present invention is not limited to the above-described embodiments, but can be embodied in various other forms. Therefore, the embodiments are merely illustrative in all respects and should not be interpreted as limiting. The scope of the present invention is defined by the claims and is not limited in any way by the text of the specification. Furthermore, all modifications and variations that fall within the equivalent scope of the claims are within the scope of the present invention. [Explanation of symbols]

[0064] 100 Image forming device 120 Manual feed tray device 200 Document feeder 201 Sheet feeding device 210 Sheet tray 210a top side 211 First tray section 212 Second tray section 212a Through hole 220 Sheet size detection unit 220a First sheet size detection unit 220b Second sheet size detection unit 221 Rotating shaft 222 Actuator 222a Contact part 222b Actuated part 223 Switch section 223a Operating part 224 Weight member G Manuscript H Supply direction Q Vertex Sa area Sb area V cross direction W width direction X depth direction Y left / right direction Z vertical direction α1 1st top surface area α1a upstream end α1b downstream end α1c Elliptical arc part α1d Straight section α2 2nd top area α2a upstream end α2b upstream region β rotation axis γ detection part

Claims

1. A sheet feeding device including a sheet placement tray on which sheets are placed, and a sheet size detection unit disposed on the sheet placement tray and detecting the size of the sheets placed on the sheet placement tray, an upper surface of the sheet loading tray has a first upper surface area including a detection portion of the sheet size detection unit that detects the sheet, and a second upper surface area other than the first upper surface area; the first upper surface region is formed in a convex shape so as to be higher than the second upper surface region, The convex shape includes a curved shape, the convexly formed surface is made up of a plurality of surfaces, each of the plurality of surfaces includes a convex curved surface; A sheet feeding device characterized in that the multiple convex curved surfaces have different radii of curvature, and the individual curved surfaces having the radii of curvature are combined and connected along the sheet feed direction, and when connected to each other, they are formed into an overall smooth curved shape.

2. 2. The sheet feeding device according to claim 1, A sheet feeding device characterized in that the second upper surface area is lower than the first upper surface area in the sheet feeding direction from the upstream end of the first upper surface area to the upstream end of the second upper surface area.

3. 3. The sheet feeding device according to claim 1, The sheet feeding device according to claim 1, wherein the first upper surface area is formed so that the apex of the convex shape is positioned at the center in the feeding direction of the sheet.

4. A sheet supplying device according to any one of claims 1 to 3, the sheet placement tray includes a first tray portion and a second tray portion connected to the first tray portion and located upstream of the first tray portion in the sheet feeding direction, The sheet feeding device, wherein the first upper surface area is provided in the second tray portion.

5. A sheet supplying device according to claim 4, A sheet feeding device, characterized in that, when the area of ​​the second tray portion is Sa and the area of ​​the first upper surface region is Sb, the relationship (Sa-Sb)>Sb is satisfied.

6. 6. The sheet feeding device according to claim 4, wherein: The sheet feeding device according to claim 1, wherein the first upper surface area is provided at a center portion in a sheet feeding direction and a width direction orthogonal to the sheet feeding direction in the second tray portion.

7. 7. The sheet feeding device according to claim 1, The second upper surface area is a flat surface, and the first upper surface area is a flat surface in the feeding direction of the sheet. a sheet supplying device characterized in that the upstream end of the sheet supplying portion is at the same height as the second upper surface area of ​​the plane, the height gradually increases from the upstream end to the apex, and the height gradually decreases from the apex to the downstream end in the sheet supplying direction, and the downstream end is at the same height as the second upper surface area.

8. 8. The sheet feeding device according to claim 1, a plurality of the sheet size detection units are arranged in parallel along the sheet feeding direction, The sheet feeding device according to claim 1, wherein the first upper surface area includes detection portions for detecting the sheets of the plurality of sheet size detection units.

9. 9. The sheet feeding device according to claim 1, The sheet feeding device according to claim 1, wherein the sheet size detection unit has an actuator that contacts the sheet and rotates about a rotation axis that extends in a direction intersecting the sheet feeding direction.

10. 10. A manual feed tray device comprising the sheet feeding device according to claim 1.

11. 10. A document feeding device comprising the sheet feeding device according to claim 1.

12. 12. An image forming apparatus comprising: a manual feed tray device according to claim 10; and / or a document feeder according to claim 11.

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