Image forming apparatus

Abstract

To solve the problem in which, in a loading tray for loading sheets of an image forming device, when all directions are covered by a dust cover, at the time of loading large-sized sheets, a device installation area increases greatly, and when an opening is provided and the large-sized sheets are allowed to protrude from the dust cover, dust enters from an opening part when using normal-sized sheets.SOLUTION: An image forming device includes: a first cover part for covering a loading tray; and a second cover part openable / closable by rotating around a rotary shaft with respect to the first cover part. An appearance surface of the second cover part facing outside with respect to a sheet storage part when the second cover part is in a closed state faces upward regarding a vertical direction when the second cover part is in an open state.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an image forming apparatus that forms an image on a sheet.

Background Art

[0002] Conventionally, examples of image forming apparatuses include electrophotographic printers such as electrophotographic copiers, LED printers, and laser beam printers, electrophotographic facsimile apparatuses, and electrophotographic word processors.

[0003] In such an image forming apparatus, there is a configuration in which the size of the apparatus main body is small, and a loading tray for loading sheets and a part of the sheets loaded on the loading tray protrude from the apparatus main body. In a configuration where the sheet is loaded protruding from the apparatus main body, dust around may adhere to the protruding sheet. When printing with dust adhering to the sheet, problems such as conveyance failure due to dust adhering to the conveyance roller or image failure due to dust entering the image forming unit may occur. <http: / / www.google.co.jp / patents / JP2021151715A?cl=en>[^1]

[0004] As a configuration for avoiding such conveyance failure and image failure, for example, as shown in JP-A-2021-151715, there is a method of installing a paper feed tray cover (hereinafter also referred to as a dust cover) that covers the sheet. With this method, even in a configuration where a part of the sheet protrudes from the apparatus main body, adhesion of dust to the sheet can be prevented.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] [^1]: 原文中此链接为日文链接,翻译时保留原文链接形式,实际使用中可能需要替换为正确的英文链接。However, the above prior art had the following problems. When all large-sized sheets (such as LEGAL size) are covered with a dust cover, rather than the standard-sized sheets (such as LETTER and A4 size) that users use frequently, the installation area of ​​the main unit increases. Alternatively, by providing an opening on the rear end of the sheet in the dust cover and allowing the sheet to protrude from the dust cover only when loading large-sized sheets, the installation area of ​​the main unit does not increase, but dust can enter through the opening even when using standard-sized sheets, reducing the effectiveness of preventing dust accumulation. The present invention has been made in view of the above points, and aims to provide an image forming apparatus that can load large-sized sheets without increasing the installation area of ​​the main unit, and without reducing the dust-preventing effect of the dust cover when using standard-sized sheets. [Means for solving the problem]

[0007] To solve the above problems, the present invention provides An image forming apparatus for forming an image on a sheet, The apparatus includes an image forming unit that forms an image on a conveyed sheet, A loading tray for loading sheets, comprising a loading tray protruding from the main body of the device, A cover unit that covers a sheet loaded on a loading tray, forming a sheet storage section between the loading tray and the sheet storage section, comprising: a first cover section that covers the upper surface of the sheet loaded on the loading tray; and a second cover section that is rotatably attached to the first cover section around a pivot axis at a position on the rear end side of the sheet with respect to the transport direction of the sheet loaded on the loading tray, and opens and closes an opening connected to the sheet storage section. Equipped with, The second cover portion is attached to the first cover portion such that when the opening is closed, the outer surface of the second cover portion faces outward relative to the sheet storage portion, and when the opening is opened, the outer surface of the second cover portion faces upward in the vertical direction. The first cover portion is rotatable between an open position, which allows the sheet to be set on the loading tray, and a closed position. the law of nature , before The second cover portion has an engaging portion for engaging with the first cover portion and keeping the second cover portion in the open state, and the first cover portion has a first engaged portion for engaging with the engaging portion. The first cover portion has a second engaged portion that engages with the engaging portion, and the second cover portion is kept closed when the engaging portion and the second engaged portion engage. The first cover portion is movable between the open position and the closed position when the sheet is loaded on the loading tray. The second cover portion has a contact portion, which is capable of contacting the sheet loaded on the loading tray when the first cover portion moves from the open position toward the closed position while the sheet is loaded on the loading tray and the second cover portion is closed. The second cover portion extends downward from the pivot axis toward the contact portion when the first cover portion is closed and the second cover portion is closed, and the contact portion is located downstream of the pivot axis in the rotational direction of the first cover portion when the first cover portion moves from the open position toward the closed position and the contact portion comes into contact with the seat when the second cover portion is closed. With respect to the direction perpendicular to the rotation axis of the second cover portion, the rotation axis is closer to the image forming portion than the contact portion, and when the contact portion comes into contact with a sheet loaded on the loading tray, the second cover portion receives a force in the direction that causes the second cover portion to open. It is characterized by the following: [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an image forming apparatus that can accommodate large-sized sheets without increasing the installation area of ​​the main unit, even when using a standard-sized cover unit, without reducing the dust-preventing effect of the cover unit during normal use. [Brief explanation of the drawing]

[0009] [Figure 1] Cross-sectional view showing the overall configuration of the image forming apparatus. [Figure 2] Perspective view showing the vicinity of the main body of the device and the cover unit 70. [Figure 3] Perspective view showing the opening and closing mechanism of the opening / closing section 73 [Figure 4] Cross-sectional view showing the vicinity of the loading tray 51 and cover unit 70. [Figure 5] Cross-sectional view showing a comparative example different from the present invention. [Figure 6] Cross-sectional view illustrating the opening and closing movement of the opening / closing section 73. [Modes for carrying out the invention]

[0010] [Example 1] A first embodiment of an image forming apparatus according to the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 shows a printer 1 as the image forming apparatus of this embodiment. Hereinafter, the configuration and functions of this printer 1 will be described. In the following description, the vertical direction is defined such that the upper side is up and the lower side is down, the front side of the printer 1 (the right side in FIG. 1) is the front, and the rear side (the left side in FIG. 1) is the rear, so the front-rear direction is defined. Also, in the state of viewing the printer 1 from the front to the rear, the left side of the printer 1 is defined as the left and the right side of the printer 1 is defined as the right, so the left-right direction will be used for the description.

[0011] A process cartridge 10 is disposed inside the apparatus main body of the printer 1. The process cartridge 10 of this embodiment integrally assembles a photosensitive drum 11 as an image carrier and a developing roller (not shown) and other process means acting on the photosensitive drum 11 inside the process cartridge 10.

[0012] A laser unit 2 is disposed at the front part of the process cartridge 10. This laser unit 2 scans and exposes the surface of the photosensitive drum 11 of the process cartridge 10 with laser light to sequentially form an electrostatic latent image. Subsequently, the electrostatic latent image is developed by a developing roller to form a toner image. A transfer roller 20 is abutted against the photosensitive drum 11. A fixing device 30 and a pair of paper discharge rollers 40 are disposed at the upper part inside the apparatus main body. A paper discharge tray 43 is disposed on the upper surface of the apparatus main body. The fixing device 30 has a fixing film 31 and a pressure roller 32. The paper discharge device 40 has a paper discharge roller 41 and a paper discharge roller 42.

[0013] When performing image formation, a sheet S loaded on a loading tray 51 of a sheet storage device 50 having a cover unit 70 as a dust cover is fed by a pickup roller 52 that rotates clockwise in the figure. In the case of double feeding, the sheet S is separated by a feed roller 53 and a separation roller 54. Next, at the nip portion of a conveyance roller 61 and a conveyance roller 62 as a pair of conveyance rollers 60, the skew of the sheet S is corrected by skew correction means (not shown).

[0014] Next, the sheet S is sent to the nip portion between the photosensitive drum 11 as the image forming unit and the transfer roller 20, and the toner image formed on the photosensitive drum 11 is transferred. Further, the sheet S onto which the toner image has been transferred is sent to the nip portion between the fixing film 31 and the pressure roller 32, where it is heated and pressed, and the toner image is fixed to the sheet S. The sheet S onto which the toner image has been fixed is discharged to the discharge tray 43 by the discharge roller 41 and the discharge roller 42. By pulling out the discharge extension tray 44 that can be stored in the apparatus main body, it is possible to prevent the discharged sheet S from falling off.

[0015] The loading tray 51 is attached to the image forming apparatus as a part of the apparatus main body and protrudes from the apparatus main body because the apparatus is miniaturized. Further, with respect to the protruding portion, a cover unit 70 detachably attached to the apparatus main body covers the upper surface and the side surface of the loading tray 51 and the sheets loaded on the loading tray 51. Also, in the present embodiment, only the cover unit 70 is configured to be detachable from the apparatus main body, but the loading tray and the cover unit may be configured as a cassette detachable from the apparatus main body.

[0016] And the cover unit 70 forms a sheet accommodating portion 74 as a space for accommodating the sheet S between the loading tray 51 and the cover unit 70. Since the sheet S loaded on the loading tray 51 is covered by the cover unit 70, the cover unit 70 can prevent dust from adhering to the sheet S.

[0017] The cover unit 70 includes a cover fixing member 71 having a mounting portion (described later but not shown in Figure 1) for attaching the cover unit 70. The cover unit 70 has a main cover 72 as a first cover portion that covers the top surface and left and right sides of the sheet S. The upstream side of the main cover 72 in the direction of transport of the sheet S has an opening 75 that connects to the sheet storage portion 74. A second cover portion, an opening / closing portion 73, is attached to the main cover 72 at a position on the rear end side of the sheet S in the direction of transport of the sheet S, so as to be rotatable around a pivot axis 73c. ​​This opening / closing portion 73 opens and closes the opening 75.

[0018] The main cover 72 is configured to open and close around the main cover pivot point 72a, as indicated by the arrow in the figure. With the main cover 72 open, the user can place the sheet S on the loading tray 51. The main cover pivot point 72a is located vertically above the sheet loading surface 51b of the loading tray 51. With the cover unit 70 removed, the loading tray 51 is rotatable counterclockwise around the tray pivot point 51a in the figure.

[0019] <Specific configuration of cover unit 70> The specific configuration of the cover unit 70 in this embodiment will be described below with reference to Figure 2. Figure 2 is a perspective view showing the main body of the device and the cover unit 70 in this embodiment.

[0020] Figure 2(a) shows a sheet S1 of a standard size (A4 size in this embodiment) that is commonly used by users frequently, loaded onto the loading tray 51, with the cover unit 70 attached. In this state, the sheet S1 is covered by the main cover 72 and the opening / closing section 73. Here, the size of the sheet in this embodiment refers to the size in the front-to-back direction of the image forming apparatus, in the direction in which the sheet is transported from the loading tray 51 in the horizontal direction.

[0021] Figure 2(b) shows the cover unit 70 detached from the main body of the device. The detachability of the cover unit 70 offers advantages such as easier jamming and a smaller package size for transport. Figure 2(c) shows the cover unit 70 rotated open around the main cover pivot point 72a. In this embodiment, maintaining this state allows the user to easily load the sheets S.

[0022] Next, the configuration of the opening / closing section 73 will be specifically described with reference to Figures 3 to 6. Figure 3 is a perspective view showing the opening / closing mechanism of the opening / closing section 73. Figure 3(a) is a perspective view when the opening / closing section 73 is in the closed state. The opening / closing section 73 has a base section 73d, an arm section 73a that can extend and elastically deform from the base section 73d, and a projection 73b located at its tip as an engaging part. When the opening / closing section 73 is in the closed state, the projection 73b engages with the hole 72b of the main cover 72, which is a second engaged part, and maintains the closed state.

[0023] Figure 3(b) is a perspective view of the opening / closing section 73 in the open position. When the user rotates the opening / closing section 73 around the pivot axis 73c, the projection 73b engages with the hole 72c, which serves as the first engaging part of the main cover 72, and the open position can be maintained. Although Figure 3 shows only the right side of the cover unit 70, the left side has a similar shape.

[0024] In this embodiment, the opening / closing part 73 is provided with a projection 73b and the main cover 72 is provided with holes 72b and 72c. However, the projection and holes may be arranged in reverse, as long as the opening / closing part 73 and the main cover 72 engage with each other.

[0025] Figure 4 is a cross-sectional view showing the vicinity of the loading tray 51 and the cover unit 70. Figure 4(a) is a cross-sectional view when the opening / closing part 73 is in the closed state, Figure 4(b) is a cross-sectional view when the opening / closing part 73 is in the open state, and Figure 4(c) is a cross-sectional view when the opening / closing part 73 has moved from the open state to the closed state. The cover unit 70 has a mounting part 76, and this mounting part 76 is elastically deformed, allowing it to be attached to and detached from the mounting part 12 of the device body.

[0026] As shown in Figure 4(a), the loading tray 51 of this embodiment can cover the front (rear side of the sheet S in the direction of sheet S transport) of a sheet S1 (A4) or smaller by closing the opening / closing section 73. In this state, the top surface and left and right sides are covered by the main cover 72, and the front surface is covered by the opening / closing section 73, which prevents dust D from adhering to the sheet S1. Here, the surface that forms the outside of the opening / closing section 73 and prevents dust D from coming from the entire surface, specifically the surface that faces away from the sheet storage section 74 (outside) when the opening / closing section 73 is in the closed state, is called the exterior surface 73e.

[0027] Figure 4(b) shows the state in which a large-sized sheet S2 (referred to as LEGAL size in this embodiment) is loaded. The sheet storage device 50 can load the sheet S2 onto the loading tray 51 by opening the opening / closing section 73. In other words, the openable / closable opening / closing section 73 allows for the loading of large-sized sheets S2 without increasing the installation area of ​​the main unit, and prevents dust D from adhering to the normal-sized sheets S1 which are used frequently.

[0028] In this embodiment, the pivot shaft 73c is positioned above the sheet loading surface 51b of the loading tray 51. Also, the outer surface 73e faces upward in the vertical direction when the opening / closing section 73 is open. Therefore, as shown in Figures 4(a) and 4(b), even if dust D adheres to the opening / closing section 73, the opening and closing of the opening / closing section 73 makes it difficult for the dust D to enter the inside of the sheet storage section 74, as shown in Figure 4(c).

[0029] Figure 5 shows a configuration in which the pivot shaft 173c is positioned downwards, as a comparative example different from the present invention. Figure 5(a) is a cross-sectional view when the opening / closing section 173 is in the open state, and Figure 5(b) is a cross-sectional view when the opening / closing section 173 is closed from the open state.

[0030] As shown in Figure 5(a), if the user maintains the open / closed section 173, dust D will adhere to the upper surface (inner surface) of the open / closed section 173. Then, as shown in Figure 5(b), the upper surface of the open / closed section 173 faces inward towards the sheet storage section 174 when it is closed, allowing the dust D to enter the sheet storage section 174.

[0031] Furthermore, even when using a large-sized sheet S2, the area of ​​the portion of the sheet S2 that is covered is larger in this embodiment compared to the example shown in Figure 5, so dust D is less likely to accumulate on the sheet S2 in this embodiment.

[0032] <Inclination of opening / closing section 73> The inclination of the opening / closing section 73 will be explained using Figure 6. Figure 6 is a cross-sectional view when the cover unit 70 is closed with the opening / closing section 73 in the closed state. Figure 6(a) is a cross-sectional view when attempting to close the main cover 72 with the opening / closing section 73 in the closed state, and Figure 6(b) is a cross-sectional view when the main cover 72 is closed from the state in Figure 6(a).

[0033] As shown in Figure 6(a), the opening / closing section 73 is provided with an inclined section 73f. The inclined section 73f is a surface that is inclined with respect to a direction perpendicular to the axial direction and vertical direction of the pivot axis 73c when the opening / closing section 73 is in the closed state, and as it goes downward in the vertical direction, it is inclined in a direction that moves away from the image forming section in the horizontal direction. The inclined section 73c is located between the uppermost part 73g and the lowermost part 73h of the opening / closing section 73.

[0034] Due to this inclined portion 73f, the pivot axis 73c is located closer to the image forming section than the lowest part 73h of the opening / closing section 73, in the direction perpendicular to the axial direction and vertical direction of the pivot axis 73c (the front-to-back direction).

[0035] In this case, with the sheet S2 loaded, if the opening / closing section 73 remains closed while the main cover 72 is moved from the open to the closed position, the lowest part 73h comes into contact with the upper surface of the sheet S2. In this embodiment, since the pivot axis 73c is positioned L1 closer to the image forming section than the lowest part 73h in the horizontal direction, the opening / closing section 73 is subjected to a force that rotates it counterclockwise around the pivot axis 73c, as indicated by the arrow in the figure.

[0036] As shown in Figure 6(b), when the main cover 72 is closed, the opening / closing part 73 rests on the sheet S2, and transport resistance is generated by the weight W1 of the opening / closing part 73. However, since the opening / closing part 73 has a small volume, W1 is small and the effect is small. In addition, when the opening / closing part 73 is closed, the projection 73b and the hole 72b are engaged, but the engagement is released if a force greater than a certain amount is applied in the direction that opens the opening / closing part 73.

[0037] Furthermore, in this embodiment, when the opening / closing section 73 is in the closed position, the uppermost part 73g is located further from the image forming section than the pivot axis 73c. ​​Therefore, even without the inclined section 73f, the opening / closing section 73 opens automatically as shown in Figure 6(b), but the inclined section 73f increases the distance L1, making it easier for the opening / closing section 73 to open.

[0038] Furthermore, with respect to the direction perpendicular to the axial direction and vertical direction of the pivot axis, the position of the pivot axis 73c and the position of the uppermost part 73g of the opening / closing section 73 are located inward from the end of the main cover 72. As a result, there is a gap between the uppermost part 73g and the end of the main cover 72, and the user can place their fingers in this gap when opening the cover unit 70 to set the seat S.

[0039] Here, as an example of a configuration different from this embodiment, Figure 6(c) shows a configuration in which the pivot axis 273c is positioned L2 closer to the main cover pivot point 272a than the lowest point 273h. In this configuration, the front cover 273 receives a force clockwise around the pivot axis 273c as indicated by the arrow in the figure, so the front cover 273 cannot be opened, and both the main cover 272 and the front cover 273 rest on the sheet S2. As a result, the self-weight W2 of the main cover 272 and the front cover 273 increases the transport resistance, which may cause transport failure. In this embodiment, W1 is smaller than W2, and the transport resistance is also significantly reduced.

[0040] As described above, the cover unit 70 of this embodiment is equipped with an openable / closable section 73, so that when the openable / closable section 73 is open, a large sheet S2 can be loaded. Furthermore, when the openable / closable section 73 is closed, all of the standard-sized sheets S1 that are used frequently can be covered by the cover unit 70. In other words, it is possible to prevent dust D from adhering to the standard-sized sheets S1 that are used frequently without increasing the printer installation area.

[0041] Furthermore, by positioning the opening / closing section 73 such that its outer surface 73e faces upward in the vertical direction when the opening / closing section 73 is open, dust D adhering to the outer surface of the opening / closing section 73 is less likely to enter the sheet storage section 74 through the opening 75 when the opening / closing section 73 is opened and closed.

[0042] In this embodiment, when the sheet S is loaded onto the loading tray 51, the sheet S protrudes to the front of the main body; however, the sheet S may also protrude to the rear of the main body. [Explanation of symbols]

[0043] 51 Loading Tray 70 Cover Unit 72 Main Cover 73 Opening / Closing Section 73c Rotary shaft 73e Exterior 74 Seat storage compartment 75 Aperture

Claims

1. An image forming apparatus for forming an image on a sheet, The apparatus includes an image forming unit that forms an image on a conveyed sheet, A loading tray for loading sheets, comprising a loading tray protruding from the main body of the device, A cover unit that covers a sheet loaded on a loading tray, forming a sheet storage section between the loading tray and the sheet storage section, comprising: a first cover section that covers the upper surface of the sheet loaded on the loading tray; and a second cover section that is rotatably attached to the first cover section around a pivot axis at a position on the rear end side of the sheet with respect to the transport direction of the sheet loaded on the loading tray, and opens and closes an opening connected to the sheet storage section. Equipped with, The second cover portion is attached to the first cover portion such that when the opening is closed, the outer surface of the second cover portion faces outward relative to the sheet storage portion, and when the opening is opened, the outer surface of the second cover portion faces upward in the vertical direction. The first cover portion is rotatable between an open position, which allows the sheet to be set on the loading tray, and a closed position. The second cover portion has an engaging portion for engaging with the first cover portion and keeping the second cover portion in the open state, and the first cover portion has a first engaged portion for engaging with the engaging portion. The first cover portion has a second engaged portion that engages with the engaging portion, and the second cover portion is kept closed when the engaging portion and the second engaged portion engage. The first cover portion is movable between the open position and the closed position when the sheet is loaded on the loading tray. The second cover portion has a contact portion, which is capable of contacting the sheet loaded on the loading tray when the first cover portion moves from the open position toward the closed position while the sheet is loaded on the loading tray and the second cover portion is closed. The second cover portion extends downward from the pivot axis toward the contact portion when the first cover portion is closed and the second cover portion is closed, and the contact portion is located downstream of the pivot axis in the rotational direction of the first cover portion when the first cover portion moves from the open position toward the closed position and the contact portion comes into contact with the seat when the second cover portion is closed. With respect to the direction perpendicular to the rotation axis of the second cover portion, the rotation axis is closer to the image forming portion than the contact portion, and when the contact portion comes into contact with a sheet loaded on the loading tray, the second cover portion receives a force in the direction that causes the second cover portion to open. An image forming apparatus characterized by the following features.

2. The image forming apparatus according to claim 1, characterized in that the pivot axis is located above the sheet loading surface of the loading tray in the vertical direction.

3. The image forming apparatus according to claim 1 or 2, characterized in that the pivot axis is located closer to the image forming section with respect to a direction perpendicular to the axial direction and vertical direction of the pivot axis, between the pivot axis and the lowest part of the second cover section.

4. The image forming apparatus according to claim 3, wherein the second cover portion has an inclined portion that is inclined with respect to a direction perpendicular to the axial direction and vertical direction of the pivot axis, and the inclined portion is inclined in a direction that moves away from the image forming portion as it goes downward with respect to the vertical when the second cover portion is in the closed state.

5. The image forming apparatus according to claim 4, characterized in that the inclined portion is located between the uppermost and lowermost parts of the second cover portion.

6. The image forming apparatus according to any one of claims 1 to 4, characterized in that, with respect to a direction perpendicular to the axial direction and vertical direction of the pivot axis, the position of the pivot axis and the uppermost position of the second cover portion are inward from the end of the first cover portion, and there is a gap between the end of the first cover portion and the uppermost portion.

7. The image forming apparatus according to any one of claims 1 to 6, wherein the second cover portion has a base portion and an arm portion extending from the base portion, and the engaging portion is provided on the arm portion.

8. The image forming apparatus according to any one of claims 1 to 7, characterized in that the engaging portion is a projection protruding from the second cover portion, and the first engaged portion and the second engaged portion are holes that engage with the projection portion, respectively.

9. The image forming apparatus according to any one of claims 1 to 8, characterized in that the loading tray is attached to the main body of the apparatus and the cover unit is detachable from the image forming apparatus.

10. With the cover unit removed from the main body of the device, The loading tray is rotatable relative to the main body of the device. The image forming apparatus according to feature 9.

11. The rotation center of the first cover portion is located above the loading tray. The image forming apparatus according to any one of claims 1 to 10, characterized by the features described herein.

12. The rotation center of the first cover portion is located downstream of the pivot axis with respect to the transport direction of the sheets loaded on the loading tray. The image forming apparatus according to any one of claims 1 to 11, characterized by the features described herein.

Images