Image forming apparatus

Abstract

The objective is to provide an image forming apparatus that avoids damage to the shaft and bearing of the extension tray, and that allows the extension tray to be returned to its original position with a simple operation. [Solution] The image forming apparatus 1 comprises a paper output tray 10 and an extension tray 20. The paper output tray 10 is equipped with ribs 14. The extension tray 20 is displaceable between a stored state and an extended state. In the extended state, if the weight on the extension tray 20 is within a predetermined value, the engaging portion 22 contacts the ribs 14 to maintain a predetermined angle. If the weight on the extension tray 20 exceeds a predetermined value, the engaging portion 22 displaces to a released state in which contact with the ribs 14 is released while maintaining the mounting state of the shaft portion 23 to the bearing portion 13.

Description

Technical Field

[0001] The present disclosure relates to image forming apparatuses such as copiers, multifunction peripherals, printers, and facsimile apparatuses.

Background Art

[0002] Conventionally, in order to accommodate sheets larger than A4 size (for example, legal paper with a long side of 355.6 millimeters) in an image forming apparatus, a rotatable extension tray may be provided at the downstream end in the discharge direction of the paper discharge tray. Generally, since there are restrictions on the space where the extension tray is placed, it is made thin and lightweight and not very strong. Also, in the case of a rotatable extension tray, the tip (point of action) of the extension tray is farther from the center (fulcrum) of rotation, and the shaft portion and bearing portion corresponding to the fulcrum of the lever principle are subjected to the force of the point of action and the point of effort, and a force several times that of the point of action is applied. Therefore, if the user accidentally presses down on the tip of the extension tray, the shaft portion and / or the bearing portion may be damaged.

[0003] Also, in some conventional extension trays, in order to suppress damage to the shaft portion and / or the bearing portion when a strong downward force is applied to the tip, the shaft portion is elastically deformed inward and the shaft portion comes out of the bearing portion. For example, Patent Document 1 below discloses a sheet material placement device including an auxiliary tray that is rotatably mounted around a support shaft. Further, in the sheet material placement device of Patent Document 1, in order to prevent the auxiliary tray from being damaged by an external impact, a structure in which the support shaft of the auxiliary tray comes out of the engagement hole when a strong impact is applied is disclosed. Thus, in the sheet material placement device of Patent Document 1, it is said that when an impact is applied to the auxiliary tray, the auxiliary tray can be detached from the sheet material placement table to prevent damage to the auxiliary tray.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] However, in the sheet material placement device described in Patent Document 1, when returning the detached auxiliary tray, the user must hold both ends of the auxiliary tray and simultaneously insert the left and right support shafts into both engagement holes on the left and right sides, which is cumbersome and time-consuming for first-time users.

[0006] Therefore, the present disclosure aims to provide an image forming apparatus that avoids damage to the shaft and bearing portions of the extension tray, and that allows the extension tray to be returned to its original position with a simple operation. [Means for solving the problem]

[0007] To solve the aforementioned problems, the present disclosure provides an image forming apparatus comprising: a paper output tray for loading sheets discharged from an outlet and having a bearing portion; and an extension tray having a shaft portion attached to the bearing portion, and the extension tray being rotatable relative to the paper output tray about the pivot axis of the shaft portion by the attachment of the shaft portion to the bearing portion, wherein the paper output tray has ribs that contact the extension tray to maintain the extension tray at a predetermined angle, and the extension tray has a base end portion and a tip end portion which are both ends in a direction perpendicular to the pivot axis, with the base end portion having an engaging portion that contacts the ribs, and the tip end portion is The extension tray is displaceable between a stored state in which the extension tray is stored, located upstream of the base end in the discharge direction from which the sheet is discharged from the discharge port, and an unfolded state in which the tip is located downstream of the base end in the discharge direction and the engaging portion maintains a predetermined angle while in contact with the rib, wherein in the unfolded state, if the weight on the extension tray is within a predetermined value, the engaging portion maintains a predetermined angle by contacting the rib, and if the weight on the extension tray exceeds the predetermined value, the extension tray is displaced to an unfolded state in which the engaging portion is released from contact with the rib while maintaining the mounting state of the shaft portion to the bearing portion. [Effects of the Invention]

[0008] According to the image forming apparatus of this disclosure, damage to the shaft and bearing portion of the extension tray can be avoided, and the extension tray can be returned to its original position with a simple operation. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of an image forming apparatus according to an embodiment of the present disclosure. [Figure 2] Figure 1 is a schematic diagram showing the inside of the image forming apparatus. [Figure 3] Figure 1 is an exploded perspective view of the sheet output device of the image forming apparatus. [Figure 4] Figure 1 is a plan view showing the paper output tray of the image forming apparatus. [Figure 5] Figure 4 is a cross-sectional view of the paper output tray along the line A1-A1. [Figure 6] Figure 4 is a cross-sectional view of the paper output tray along the line A2-A2. [Figure 7] Figure 1 is a plan view showing the extension tray of the image forming apparatus. [Figure 8] This is a cross-sectional view taken along line A3-A3 in Figure 7. [Figure 9] Figure 1 is a perspective view showing the extension tray in its stored position in the image forming apparatus. [Figure 10] This is a cross-sectional view showing the stored state of the extension tray in the image forming apparatus shown in Figure 1. [Figure 11] Figure 1 is a perspective view showing the extended tray in the image forming apparatus. [Figure 12] This is a cross-sectional view showing the extended tray in the image forming apparatus shown in Figure 1. [Figure 13] Figure 1 is a perspective view showing the extended tray in the released state in the image forming apparatus. [Figure 14] This is a cross-sectional view showing the extended tray in the image forming apparatus shown in Figure 1. [Figure 15]In the image forming apparatus of FIG. 1, it is a cross-sectional view showing a main part when the engagement of the engaging part is released. [Figure 16] In the image forming apparatus of FIG. 1, it is a cross-sectional view showing a main part in the deployed state. [Figure 17] In the image forming apparatus of FIG. 1, it is a cross-sectional view showing the contact distance in the deployed state.

Embodiments for Carrying out the Invention

[0010] Hereinafter, the image forming apparatus 1 according to an embodiment of the present disclosure will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0011] [Image Forming Apparatus] FIG. 1 is a perspective view showing the image forming apparatus 1 according to the present embodiment. FIG. 2 is a schematic view in a side view showing the inside of the image forming apparatus 1.

[0012] The image forming apparatus 1 is a multifunction printer having a copying function, a scanner function, a facsimile function, and a printer function. As shown in FIG. 1, the image forming apparatus 1 includes a document feeder 2 and a device main body 3.

[0013] In this specification, the left-right direction (the width direction of the image forming apparatus 1) in the state where the image forming apparatus 1 is installed will be described as the "left-right direction X". In this specification, the front-rear direction in the state where the image forming apparatus 1 is installed will be described as the "front-rear direction Y". Also, the front in the front-rear direction Y will be described as "front Y1", and the rear will be described as "rear Y2". In this specification, the up-down direction in the state where the image forming apparatus 1 is installed will be described as the "up-down direction Z". Also, the upper side in the up-down direction Z will be described as "upper Z1", and the lower side will be described as "lower Z2".

[0014] The image forming apparatus 1 transmits the image of the original document read by the image reading unit (not shown) to an external source. The image forming apparatus 1 also forms an image on a sheet P, such as recording paper, in color or monochrome, based on the image of the original document read by the image reading unit or the image received from an external source. The image forming apparatus 1 may be a monochrome image forming apparatus. The image forming apparatus 1 may also be a color image forming apparatus of another form.

[0015] As shown in Figure 2, the main body of the apparatus 3 comprises an image forming unit 4, a paper feed cassette 5, and a housing 9. The image forming apparatus 1 also comprises an image reading unit, an optical scanning device, an intermediate transfer belt device, a secondary transfer device, a fixing device, etc., which are not shown in the figure. The image forming apparatus 1 is configured to house the image forming unit 4, the paper feed cassette 5, etc. inside the housing 9.

[0016] As shown in Figure 2, a sheet transport path R is formed inside the housing 9 of the image forming apparatus 1. Sheets P supplied from the paper feed cassette 5 have images formed in the image forming unit 4 and are transported along the sheet transport path R via a fixing device and the like. The sheets P with the formed images are discharged from the discharge port 6 to the discharge tray 10 by the discharge roller 7. The discharge tray 10 constitutes the sheet discharge device 30, which will be described later.

[0017] [Embodiment] Next, embodiments of the present disclosure will be described. Figure 3 is an exploded perspective view of the sheet output device 30 provided in the image forming apparatus 1. Figure 4 is a plan view of the output tray 10. Figure 5 is a cross-sectional view of the output tray 10 in Figure 4 taken along the line A1-A1. Figure 6 is a cross-sectional view of the output tray 10 in Figure 4 taken along the line A2-A2. Figure 7 is a plan view showing the extension tray 20. Figure 8 is a cross-sectional view of Figure 7 taken along the line A3-A3. Figure 9 is a perspective view showing the extension tray 20 in its stored state. Figure 10 is a cross-sectional view showing the extension tray 20 in its stored state. Figure 11 is a perspective view showing the extension tray 20 in its deployed state. Figure 12 is a cross-sectional view showing the extension tray 20 in its deployed state. Figure 13 is a perspective view showing the extension tray 20 in its released state. Figure 14 is a cross-sectional view showing the extension tray 20 in its released state. Figure 15 is a cross-sectional view showing the main part when the engagement of the engagement part 22 is released. Figure 16 is a cross-sectional view showing the main part when it is in the deployed state. Figure 17 is a cross-sectional view showing the contact distance N when the device is unfolded.

[0018] As shown in Figure 1, the image forming apparatus 1 includes a sheet output device 30. As shown in Figure 1, the sheet output device 30 includes an output tray 10 and an extension tray 20. In other words, the image forming apparatus 1 includes an output tray 10 and an extension tray 20.

[0019] As shown in Figure 2, in the image forming apparatus 1, the sheet P on which the image has been formed by the image forming unit 4 is discharged from the discharge port 6 toward the front Y1. In other words, in the image forming apparatus 1 of this embodiment, the sheet P is discharged forward from the rear Y2 toward the front Y1. Also, as shown in Figure 2, the housing 9 has a paper discharge space S formed in front Y1 of the discharge port 6 through which the sheet P is discharged. As shown in Figure 1, the housing 9 of the main body of the apparatus 3 has a sheet removal port 9a formed in front Y1 of the paper discharge space S as an opening for removing the sheet P.

[0020] In this specification, the direction in which the sheet P is discharged from the discharge port 6 will be referred to as "discharge direction B". Furthermore, the position downstream of discharge direction B (the position forward in discharge direction B) will be referred to as "downstream B1", and the position upstream of discharge direction B (the position backward in discharge direction B) will be referred to as "upstream B2". In addition, in this specification, the direction perpendicular to discharge direction B and the vertical direction Z will be referred to as "width direction W".

[0021] In this embodiment, as described above, the discharge direction B in the image forming apparatus 1 is from the rear Y2 towards the front Y1. That is, in this embodiment, the discharge direction B is aligned with the front-to-back direction Y. Also, in this embodiment, the width direction W coincides with the left-to-right direction X of the apparatus.

[0022] The output tray 10 holds the sheets P to be discharged. As shown in Figure 2, the output tray 10 is located above Z1 the image forming unit 4. Specifically, as shown in Figure 2, an output space S is formed above Z1 the image forming unit 4, and the output tray 10 is located below Z2 the output space S.

[0023] As shown in Figure 2, the output tray 10 constitutes the lower surface of the output space S. As shown in Figure 4, the output tray 10 is a substantially rectangular member in plan view. As shown in Figure 3, the output tray 10 is provided with a housing section 11, a displacement-allowing section 12, a bearing section 13, a rib 14, and a protrusion 17. The output tray 10 is integrally formed with the housing section 11, the displacement-allowing section 12, the bearing section 13, the rib 14, and the protrusion 17.

[0024] In this embodiment, an example is shown in which the rib 14 is formed integrally with the paper output tray 10 (an example in which the rib 14 is formed as part of the paper output tray 10), but the image forming apparatus disclosed herein is not limited to this embodiment. For example, the rib may be separate from the paper output tray. Also, for example, the rib may be made of a different material than the paper output tray. Furthermore, for example, the rib may be formed integrally with the paper output tray by insert molding or the like.

[0025] The storage section 11 houses the extension tray 20 when stored. As shown in Figure 3, the storage section 11 is formed in a concave shape. As shown in Figure 3, the storage section 11 is located in the center in the width direction W. As shown in Figure 4, the storage section 11 has a roughly rectangular appearance in plan view.

[0026] The bearing portion 13 is a hole for fitting the shaft portion 23 of the extension tray 20. As shown in Figure 3, the bearing portions 13 are provided at both ends of the housing portion 11 in the width direction W.

[0027] The displacement-allowing section 12 is a space that allows for displacement of the base end portion 20a of the extension tray 20 when the extension tray 20 is displaced (when it rotates around the shaft portion 23). As shown in Figure 5, the displacement-allowing section 12 is provided downstream B1 of the housing portion 11.

[0028] The ribs 14 maintain the extension tray 20 in a predetermined position when deployed. As shown in Figure 3, the ribs 14 are provided at both ends of the storage section 11 in the width direction W. As shown in Figure 6, the ribs 14 have a contact surface 15 and a rib chamfer 16. The contact surface 15 is in contact with the engaging portion 22 of the extension tray 20 when it is deployed. The rib chamfer 16 is in contact with the engaging portion 22 when the extension tray 20 is returned to the deployed state after it has been disengaged from the engaged state (deployed state).

[0029] The extension tray 20 receives the sheets P discharged from the output tray 10. As shown in Figure 7, the extension tray 20 is a roughly rectangular plate-shaped member in plan view. As shown in Figure 8, the extension tray 20 comprises a main body 21, an engaging part 22, and a shaft part 23. The extension tray 20 is integrally constructed from the main body 21, the engaging part 22, and the shaft part 23.

[0030] The shaft portion 23 is fitted into the bearing portion 13 and functions as the pivot axis of the extension tray 20. In this specification, the direction in which the pivot axis C of the extension tray 20 extends is referred to as the "axial direction D". In the description of the extension tray 20, the direction perpendicular to the axial direction D is referred to as the "tray longitudinal direction E". Furthermore, of the two ends of the tray longitudinal direction E, the end on which the shaft portion 23 is provided is referred to as the "base end portion 20a", and the other end is referred to as the "tip end portion 20b".

[0031] As shown in Figure 3, the shaft portion 23 is provided at the base end portion 20a. Also, as shown in Figure 7, the shaft portions 23 are provided at both ends of the extension tray 20 in the axial direction D. In the image forming apparatus 1, the shaft portions 23 of the extension tray 20 are fitted into the left and right bearing portions 13 of the paper output tray 10, thereby mounting the extension tray 20 so that it can rotate around the pivot axis C relative to the paper output tray 10.

[0032] As shown in Figure 8, the engaging portion 22 is provided at the base end portion 20a. The engaging portion 22 is formed at an angle to the main body portion 21. In cross-sectional view, the extension tray 20 has a shape such that the engaging portion 22 is bent relative to the main body portion 21.

[0033] In the image forming apparatus 1, the extension tray 20 can be rotated around the pivot axis C, allowing it to be displaced to various positions with different orientations relative to the output tray 10 while the shaft portion 23 remains inserted into the bearing portion 13. Each of these states will be described below.

[0034] [Storage status] In the image forming apparatus 1 of this embodiment, the extension tray 20 can be stored in the storage section 11 of the output tray 10. In this specification, the state in which the extension tray 20 is stored in the storage section 11 of the output tray 10 will be referred to as the "storage state" and described accordingly. As shown in Figure 9, in the storage state, the extension tray 20 is folded. Also, as shown in Figure 10, in the storage state, the tip portion 20b of the extension tray 20 is located upstream B2 of the base portion 20a, and the extension tray 20 is stored in the storage section 11 (folded state).

[0035] [Deployment status] In the image forming apparatus 1 of this embodiment, the extension tray 20 is expandable to receive the discharged sheet P. In this specification, the expanded state of the extension tray 20 will be referred to as the "expanded state." As shown in Figure 11, in the expanded state, the extension tray 20 is positioned to protrude outside the paper discharge space S. As shown in Figure 12, in the expanded state, the engaging portion 22 maintains a predetermined angle while in contact with the rib 14. Also, as shown in Figure 12, in the expanded state, the extension tray 20 is positioned so that its tip portion 20b is downstream B1 from the base portion 20a and above Z1 from the base portion 20a. That is, in the expanded state, the extension tray 20 is positioned so that its tip portion 20b is tilted upward Z1. This allows the image forming apparatus 1 to prevent the discharged sheet P from falling out of the paper discharge space S.

[0036] [Released state] In the image forming apparatus 1 of this embodiment, if the weight applied to the extension tray 20 exceeds a predetermined value, the extension tray 20 is displaced to a released state in which the contact between the engaging portion 22 and the rib 14 is released while maintaining the mounting state of the shaft portion 23 to the bearing portion 13 (see Figure 13). In this specification, the state in which the contact between the engaging portion 22 and the rib 14 is released while maintaining the mounting state of the shaft portion 23 to the bearing portion 13 will be referred to and described as the "released state". As shown in Figure 14, in the released state, the extension tray 20 is restricted from rotating (displacing) by the main body portion 21 contacting the protrusion 17 of the paper output tray 10. As shown in Figure 14, in the released state, the extension tray 20 is positioned so that its tip portion 20b is downstream B1 from the base portion 20a and below Z2 from the base portion 20a. That is, in the extended state, the extension tray 20 is positioned so that its tip portion 20b is tilted downward Z2.

[0037] As described above, in the image forming apparatus 1 of this embodiment, the extension tray 20 is displaceable between a stored state, where it is stored in the output tray 10, and an extended state, where it is extended from the output tray 10. This allows the image forming apparatus 1 to, for example, extend the extension tray 20 when outputting relatively large sheets P, such as legal paper, to prevent the output sheets P from falling out of the output space S, while extending the extension tray 20 when not outputting large sheets P to avoid the extension tray 20 getting in the way. For example, when outputting A4 size sheets P (long side 297 mm), the extension tray 20 is stored, and when outputting sheets P larger than A4 size (for example, legal paper with a long side of 355.6 mm), the extension tray 20 is extended to prevent the sheets P from falling out of the output space S.

[0038] [First Embodiment] The image forming apparatus 1 of this embodiment includes a paper output tray 10 on which sheets P discharged from the output port 6 are loaded and which is provided with a bearing portion 13, and an extension tray 20 which is provided so as to be rotatable relative to the paper output tray 10 about the rotation axis C of the shaft portion 23, with the shaft portion 23 attached to the bearing portion 13. In the image forming apparatus 1 of this embodiment, the paper output tray 10 is provided with ribs 14 that contact the extension tray 20 and maintain the extension tray 20 at a predetermined angle. In the image forming apparatus 1 of this embodiment, the extension tray 20 has a base end portion 20a and a tip end portion 20b which are the base end portion 20a and Furthermore, in the image forming apparatus 1 of this embodiment, the extension tray 20 is displaceable between a stored state in which the tip portion 20b is located upstream B2 in the discharge direction B from the base portion 20a and the extension tray 20 is stored, and an extended state in which the tip portion 20b is located downstream B1 in the discharge direction B from the base portion 20a and the engaging portion 22 maintains a predetermined angle while in contact with the rib 14. Moreover, in the image forming apparatus 1 of this embodiment, in the extended state, if the weight on the extension tray 20 is within a predetermined value, the engaging portion 22 maintains a predetermined angle by contacting the rib 14, and if the weight on the extension tray 20 exceeds a predetermined value, the extension tray 20 is displaced to a released state in which the engaging portion 22 is released from contact with the rib 14 while maintaining the mounting state of the shaft portion 23 to the bearing portion 13.

[0039] In the image forming apparatus 1 of this embodiment, when the extension tray 20 is extended, the engaging portion 22 of the extension tray 20 comes into contact with the contact surface 15 of the rib 14, restricting the upward displacement Z1 of the base end portion 20a and maintaining its orientation at a predetermined angle. In other words, the image forming apparatus 1 is provided with a rib 14 for holding the extension tray 20 in a predetermined angle (or orientation).

[0040] In a rotating extension tray, the tip, which is the point of application of force, is farther away from the center of rotation, which is the fulcrum. The shaft and bearing, which correspond to the fulcrum in the lever principle, are subjected to the combined forces of the point of application and the point of effort, resulting in a force several times greater than that of the point of application. Therefore, if the tip of the extension tray is accidentally pushed downwards Z2, the shaft and / or bearing may be damaged.

[0041] In contrast, in the image forming apparatus 1 of this embodiment, if the weight on the extension tray 20 exceeds a predetermined value, the contact between the engaging portion 22 and the rib 14 is released while maintaining the mounting state of the shaft portion 23 to the bearing portion 13. Specifically, in the image forming apparatus 1 of this embodiment, if a strong downward force is applied to the tip portion 20b of the extension tray 20, the shaft portion 23 does not come off the bearing portion 13 (while maintaining the insertion of the shaft portion 23 into the bearing portion 13), and the engagement between the engaging portion 22 and the contact surface 15 is released. Thus, in the image forming apparatus 1 of this embodiment, when the extension tray 20 is in the extended state, if a certain load is applied to the extension tray 20, the engaging portion 22 will move over the rib 14 and the engaging portion 22 will detach from the rib 14 before the shaft portion 23 supporting the extension tray 20 is damaged. Therefore, in this embodiment, if the weight on the extension tray 20 becomes excessive (exceeds a predetermined value), the image forming apparatus 1 can suppress further load on the shaft portion 23 and the bearing portion 13, thereby preventing damage to the shaft portion 23 and the bearing portion 13.

[0042] The weight at which the extension tray 20 is released (a predetermined value) can be set according to the maximum number of sheets that can be ejected to the output tray 10 (maximum stacking capacity) and the weight at which the shaft 23 and / or bearing 13 are damaged. For example, the weight at which the extension tray 20 is released (a predetermined value) can be set to the weight at the maximum stacking capacity (first weight value) plus a certain amount of additional weight. Furthermore, the weight at which the extension tray 20 is released (a predetermined value) should be less than the weight at which the shaft 23 and / or bearing 13 are damaged (second weight value). Specifically, the weight at which the extension tray 20 is released (a predetermined value) can be set to be the first weight value plus a certain amount of additional weight, and less than the second weight value (first weight value < predetermined value (first weight value + additional value) < second weight value).

[0043] Furthermore, if the shaft is designed to elastically deform inward and detach from the bearing to prevent damage to the shaft and / or bearing, then when putting the detached extension tray back in place, the user must hold the extension tray and simultaneously reattach both the left and right shafts and bearings, which is cumbersome and time-consuming for first-time users.

[0044] In contrast, in the image forming apparatus 1 of this embodiment, the contact between the engaging portion 22 and the rib 14 is released while the mounting state of the shaft portion 23 to the bearing portion 13 is maintained. Therefore, when returning from the released state to the unfolded state, it is not necessary to insert the shaft portion 23 into the bearing portion 13.

[0045] Therefore, according to the image forming apparatus 1 of this embodiment, damage to the shaft portion 23 of the extension tray 20 and the bearing portion 13 of the output tray 10 is avoided, and the extension tray 20 can be returned from a detached state (released state) with a simple operation (for example, by pushing the base end portion 20a of the extension tray 20 downward Z2).

[0046] [Second Embodiment] In the image forming apparatus 1 of this embodiment, the engaging portion 22 is made of an elastically deformable material. Furthermore, in the image forming apparatus 1 of this embodiment, when the extension tray 20 is displaced from the deployed state to the released state, the engaging portion 22 elastically deforms and the engagement with the rib 14 is released, causing the tray to be displaced from the deployed state to the released state.

[0047] In the image forming apparatus 1 of this embodiment, the output tray 10 and the extension tray 20 are made of a resin material (polycarbonate ABS) which is a mixture of polycarbonate (PC) and acrylonitrile butadiene styrene resin (ABS resin). Furthermore, in the image forming apparatus 1 of this embodiment, the engaging portion 22 is integrally formed with the extension tray 20. Therefore, the engaging portion 22 is made of polycarbonate ABS. Polycarbonate ABS has moderate flexibility and can withstand excessive force to some extent while maintaining its shape. This makes it possible to configure the engaging portion 22 to have both moderate flexibility and strength.

[0048] The materials used for the engaging parts (extension tray) and output tray are not limited to those described above. For example, the extension tray and output tray may be made of other resin materials. In addition to the polycarbonate ABS mentioned above, other resin materials such as ABS resin, polycarbonate, and polyethylene terephthalate (PET) can be used.

[0049] As shown in Figure 15, in the image forming apparatus 1 of this embodiment, when the extension tray 20 is displaced from the deployed state to the released state, the engaging portion 22 is pressed against the contact surface 15 of the rib 14 and elastically deforms toward the downstream B1 (see arrow H in Figure 15). As a result, the engagement between the engaging portion 22 and the rib 14 of the extension tray 20 is released, allowing the base end portion 20a to be displaced upward Z1, and the extension tray 20 is displaced from the deployed state to the released state.

[0050] According to the image forming apparatus 1 of this embodiment, a complex structure is not required, and when force is applied to the extension tray 20, the engagement between the rib 14 and the engaging portion 22 is released, allowing the extension tray 20 to be displaced.

[0051] [Third Embodiment] In the image forming apparatus 1 of this embodiment, the engaging portion 22 is made of an elastically deformable material. Furthermore, in the image forming apparatus 1 of this embodiment, when the extension tray 20 is displaced from the released state to the deployed state, the engaging portion 22 elastically deforms and overcomes the rib 14, thereby displacing it from the released state to the deployed state.

[0052] As shown in Figure 15, in the image forming apparatus 1 of this embodiment, when the extension tray 20 is displaced from the released state to the deployed state, the engaging portion 22 is pressed against the tip portion (rib chamfer portion 16) of the rib 14, causing it to elastically deform in a direction away from the rib 14 (see arrow H in Figure 15). As a result, the engagement between the engaging portion 22 and the rib 14 is released, allowing the extension tray 20 to be displaced upward Z1 of the base end portion 20a, and it is displaced from the released state to the deployed state.

[0053] According to the image forming apparatus 1 of this embodiment, a complex structure is not required, and the extension tray 20 can be displaced to an unfolded state when it is released. Furthermore, according to the image forming apparatus 1 of this embodiment, the extension tray 20 can be returned to its original state (unfolded state) by pushing the base end 20a of the extension tray 20 downward Z2 with a force sufficient to elastically deform the engaging portion 22.

[0054] [Fourth Embodiment] In the image forming apparatus 1 of this embodiment, when the extension tray 20 is released, the tip portion 20b is located below Z2 from the base portion 20a.

[0055] Specifically, as shown in Figure 14, in the released state, the extension tray 20 has its tip 20b positioned below its base 20a at Z2, and is in a downward sloping position from upstream B2 to downstream B1. In other words, in the released state, the extension tray 20 is in a position where its base 20a is raised.

[0056] In the image forming apparatus 1 of this embodiment, when returning from the released state to the original position (deployed state), the extension tray 20 can be returned with a simple operation of pushing the base end 20a downward Z2.

[0057] [Fifth Embodiment] In the image forming apparatus 1 of this embodiment, the rib 14 and / or the engaging portion 22 (both the rib 14 and the engaging portion 22 in this embodiment) have a chamfered portion 31 formed on the part where the rib 14 and the engaging portion 22 come into contact when the extension tray 20 is displaced from the released state to the deployed state.

[0058] More specifically, as shown in Figure 15, the tip of the rib 14 comes into contact with the engaging portion 22 when the extension tray 20 is displaced from the released state to the deployed state. The tip of the rib 14 has a chamfered rib chamfered portion 16 (chamfered portion 31) formed thereon. Also, when the extension tray 20 is displaced from the released state to the deployed state, the boundary portion of the engaging portion 22 between the engaging portion 22 and the main body portion 21 first comes into contact with the rib 14, and then the tip portion comes into contact with the rib 14. The boundary portion of the engaging portion 22 between the engaging portion 22 and the main body portion 21 has a first chamfered portion 24 (chamfered portion 31) formed thereon, which is chamfered to form a curved surface. Furthermore, the tip of the engaging portion 22 has a second chamfered portion 25 (chamfered portion 31) formed thereon, which is chamfered to form a curved surface.

[0059] When the extension tray 20 is returned from the released state to the deployed state, the first chamfered portion 24 and the second chamfered portion 25 come into contact with the rib chamfered portion 16, and the engaging portion 22 is pressed by the rib 14 and elastically deforms toward the downstream B1. Also, as the engaging portion 22 elastically deforms, the base end portion 20a moves over the rib chamfered portion 16 from above Z1 to below Z2, and the extension tray 20 is displaced from the released state to the deployed state.

[0060] As a result, in the image forming apparatus 1 of this embodiment, when returning from the released state to the deployed state, the engaging portion 22 is less likely to get caught on the rib 14, and the engaging portion 22 is more likely to overcome the rib 14. Therefore, in the image forming apparatus 1 of this embodiment, when returning the extension tray 20 to the deployed state, the extension tray 20 can be returned to the deployed state by pushing the base end portion 20a of the extension tray 20 downward Z2 with light force, making it easier to return the extension tray 20 to the deployed state.

[0061] [Sixth Embodiment] In the image forming apparatus 1 of this embodiment, the ribs 14 are provided at positions that contact both ends of the extension tray 20 in the axial direction D from which the pivot axis C extends.

[0062] As shown in Figure 3, the ribs 14 are provided on both sides in the width direction W of the housing section 11 in which the extension tray 20 is housed. That is, the ribs 14 are configured to contact a portion (both ends) of the extension tray 20 when deployed. In other words, in the image forming apparatus 1 of this embodiment, the contact area between the engaging portion 22 and the ribs 14 is smaller when deployed compared to the case where the ribs 14 contact the entire axial direction D of the extension tray 20.

[0063] In the image forming apparatus 1 of this embodiment, when a strong downward force is applied to the extension tray 20 in the unfolded state, the contact area between the rib 14 and the engaging portion 22 is small, making it easier for the engaging portion 22 to detach from the rib 14. As a result, the image forming apparatus 1 can release the engagement between the engaging portion 22 and the rib 14 before the bearing portion 13 is damaged. Furthermore, in the image forming apparatus 1 of this embodiment, when the engaging portion 22 detaches from the rib 14 (when it is released), it is easier to return the extension tray 20 to its original position.

[0064] [Seventh Embodiment] In the image forming apparatus 1 of this embodiment, the contact surface 15 of the rib 14 that contacts the engaging portion 22 in the deployed state has an angle that slopes downward toward the upstream B2, which is greater than the angle of the straight line (normal L2) connecting the rotation center Ca of the extension tray 20 and the contact point Pa with the extension tray 20 in the deployed state.

[0065] To explain in more detail, as shown in Figure 16, when the contact surface 15 receives the load of the extension tray 20, the force acting on the contact surface 15 is in the direction along the tangent L3 passing through the contact point Pa on a circle (virtual circle L1) centered on the pivot center Ca (direction of action G). Therefore, if the contact surface 15 is positioned perpendicular to the direction of action G (the direction in which the tangent L3 extends) (along the normal L2), the contact surface 15 will strike perpendicular to the direction of the force due to the weight of the extension tray 20, making it difficult for the engagement between the rib 14 and the engaging portion 22 to be released.

[0066] In contrast, in the image forming apparatus 1 of this embodiment, the contact surface 15 is configured to form an angle with respect to the normal L2 and to slope downward toward the upstream B2. In other words, in the image forming apparatus 1, the angle of the contact surface 15 is set to relieve the load of the extension tray 20. Therefore, in the image forming apparatus 1, when a load is applied to the extension tray 20, the engaging portion 22 is more likely to detach from the rib 14.

[0067] Thus, in the image forming apparatus 1 of this embodiment, the engagement between the rib 14 and the engaging portion 22 is easily released when excessive weight is applied to the extension tray 20. This allows the contact surface 15 to withstand the load applied to the extension tray 20, while also making it easier to release the engagement between the rib 14 and the engaging portion 22 when excessive weight is applied to the extension tray 20, thereby suppressing damage to the shaft portion 23 and the bearing portion 13.

[0068] Next, we will explain the length (area) over which the engaging portion 22 and the contact surface 15 come into contact in the unfolded state. In the following explanation, the portion of the engaging portion 22 that comes into contact with the contact surface 15 in the unfolded state will be referred to as the "contact region 26". The length from the downstream end of B1 to the upstream end of B2 of the contact region 26 will be referred to as the "contact distance N".

[0069] As shown in Figure 17, the contact distance N of the contact area 26 is a predetermined length. In the image forming apparatus 1 of this embodiment, the contact distance N is set to correspond to the maximum number of sheets that can be stacked in the image forming apparatus 1. In the image forming apparatus 1 of this embodiment, the contact distance N is, for example, 0.4 millimeters. In the image forming apparatus of this disclosure, the contact distance N can be set as appropriate. For example, the contact distance N can be set in the range of 0.1 to 0.8 millimeters.

[0070] In the image forming apparatus 1, the maximum number of sheets P that can be loaded onto the extension tray 20 (the number of sheets P that will be released) can be set by adjusting the length of the contact distance N. In this way, the image forming apparatus 1 can adjust the load of sheets P (the load when the engaging part 22 detaches from the rib 14) by adjusting the contact distance N (contact area) between the rib 14 and the engaging part 22 in the deployed state.

[0071] Although embodiments of the image forming apparatus of the present disclosure have been described above, the image forming apparatus of the present disclosure is not limited to the embodiments described above.

[0072] For example, in the above embodiment, the sheet output device 30 was shown to be provided so as to correspond to the output port 6 from which the sheet P on which the image is formed is discharged. However, the sheet output device (output tray and extension tray) may also be provided in the document feeder.

[0073] In this embodiment, a front-discharging image forming apparatus 1 is shown as an example, but the image forming apparatus of this disclosure is not limited to front-discharging, and may discharge sheets in either the left or right direction.

[0074] This disclosure is not limited to the embodiments described above and can be implemented in various other ways. Therefore, these embodiments are merely illustrative in all respects and should not be constrained. The scope of this disclosure is defined by the claims and is not restricted by the text of the specification. Furthermore, any variations or modifications within the equivalent scope of the claims are all within the scope of this disclosure. [Explanation of Symbols]

[0075] 1. Image forming apparatus 6 Outlet 10 Paper output tray 13 Bearing section 14 Ribs 15 Contact surface 16. Rib chamfered section (chamfered section) 20 Extension Trays 20a Proximal end 20b Tip 22 Engaging part 23 Shaft section 24. First chamfered section (chamfered section) 25. Second chamfered section (chamfered section) 30-sheet paper output device 31 Chamfer B Discharge direction B1 Downstream B2 upstream C Rotary axis Ca rotation center D Axial direction E Tray Longitudinal Direction L1 Virtual Yen L2 normal L3 tangent P Sheet Pa contact point

Claims

1. A paper output tray, equipped with a bearing section, is used to load the sheets discharged from the discharge port. An image forming apparatus comprising: an extension tray having a shaft portion attached to the bearing portion, and an extension tray that is rotatable relative to the paper output tray about the pivot axis of the shaft portion by the attachment of the shaft portion to the bearing portion, The output tray is provided with ribs that contact the extension tray and maintain the extension tray at a predetermined angle. The extension tray is Of the base end and tip end, which are the ends in a direction perpendicular to the pivot axis, the base end is provided with an engaging portion that abuts against the rib. The tip is located upstream of the base end in the discharge direction from which the sheet is discharged from the discharge port, and the extension tray is stored in the stored state, The tip portion is located downstream of the base portion in the discharge direction, and the engaging portion is displaceable to maintain a predetermined angle while in contact with the rib, In the aforementioned unfolded state, If the weight on the extension tray is within a predetermined value, the engaging portion contacts the rib and maintains a predetermined angle. An image forming apparatus characterized in that, when the weight applied to the extension tray exceeds the predetermined value, the shaft portion is displaced to a released state in which the contact between the engaging portion and the rib is released while maintaining the mounting state of the shaft portion to the bearing portion.

2. An image forming apparatus according to claim 1, The aforementioned engaging portion is made of an elastically deformable material. The image forming apparatus is characterized in that the extension tray is displaced from the deployed state to the released state by the elastic deformation of the engaging portion and the release of engagement with the rib when the extension tray is displaced from the deployed state to the released state.

3. An image forming apparatus according to claim 1, The aforementioned engaging portion is made of an elastically deformable material. The image forming apparatus is characterized in that the extension tray is displaced from the released state to the deployed state by the engaging portion elastically deforming and overcoming the rib when the tray is displaced from the released state to the deployed state.

4. An image forming apparatus according to claim 1, The image forming apparatus is characterized in that, in the released state, the tip of the extension tray is located below the base end.

5. An image forming apparatus according to claim 1, The image forming apparatus is characterized in that the rib and / or the engaging portion has a chamfered portion formed on the part of the rib that comes into contact with the engaging portion when the extension tray is displaced from the released state to the deployed state.

6. An image forming apparatus according to claim 1, The image forming apparatus is characterized in that the ribs are provided at positions that contact both ends of the extension tray in the axial direction from which the pivot axis extends.

7. An image forming apparatus according to claim 1, The image forming apparatus is characterized in that the contact surface of the rib that contacts the engaging portion in the deployed state has an angle that slopes downward toward the upstream direction, which is greater than the angle of the straight line connecting the pivot center of the extension tray and the contact point with the extension tray in the deployed state.

Images