CN110007572B

CN110007572B - Sheet discharge apparatus and image forming apparatus

Info

Publication number: CN110007572B
Application number: CN201811291470.2A
Authority: CN
Inventors: 板垣裕介; 藤田正彦; 渥美竜文
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 2017-11-10
Filing date: 2018-10-31
Publication date: 2022-05-03
Anticipated expiration: 2038-10-31
Also published as: US20190144232A1; CN110007572A; JP2019089608A; JP7005299B2

Abstract

Providing: the sheet pressing mechanism and the image forming apparatus can effectively prevent the sheets from being stacked on the discharge tray in a state in which the leading ends of the sheets are bent downward by suppressing the middle folding of the sheets when the discharged sheets are brought into contact with the pressing member. The sheet pressing mechanism includes a pressing member that presses a sheet that undulates in a width direction orthogonal to a sheet discharge direction and is additionally bent when the sheet is discharged toward the discharge tray. The pressing member has a first pressing region that presses a portion of the discharged sheet other than a vertex of the peak portion of the sheet when the sheet abuts against the pressing member.

Description

Sheet discharge apparatus and image forming apparatus

Technical Field

The present invention relates to a sheet pressing mechanism and an image forming apparatus such as a copier, a multifunction peripheral, a printer, and a facsimile machine.

Background

As an image forming apparatus, there is known an apparatus including a sheet pressing mechanism including: a pressing member that presses a sheet such as paper when the sheet is discharged to a discharge tray (see patent document 1).

However, when the leading end of the sheet comes into contact with the upstream side (base end side) of the discharge tray when the discharged sheet is placed on the discharge tray, the following problems occur. That is, the sheet is placed on the discharge tray while moving on the discharge tray in a state where the leading end of the sheet is in contact with the upstream side of the discharge tray. At this time, if the leading end of the sheet does not move smoothly on the discharge tray, the sheet is stacked on the discharge tray in a state where the leading end is bent downward, for example.

From such a viewpoint, in the conventional image forming apparatus, the sheet is undulated in the width direction orthogonal to the sheet discharge direction to impart a deflection to the sheet. In this way, the leading end of the sheet can be brought into contact with the downstream side (leading end side) of the discharge tray. Therefore, for example, it is possible to effectively prevent the sheets from being stacked on the discharge tray in a state where the leading end is bent downward.

However, when the discharged sheet comes into contact with the pressing member, the sheet may be folded at the contact position with the pressing member (the sheet may be crushed). In this case, the leading end of the sheet cannot be brought into contact with the downstream side of the discharge tray.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2014-47067

Disclosure of Invention

Technical problem to be solved by the invention

In this regard, patent document 1 does not show any middle fold of the sheet when the discharged sheet abuts against the pressing member.

Accordingly, an object of the present invention is to provide: the sheet pressing mechanism and the image forming apparatus can effectively prevent the sheets from being stacked on the discharge tray in a state in which the leading ends of the sheets are bent downward by suppressing the middle folding of the sheets when the discharged sheets are brought into contact with the pressing member.

Means for solving the problems

In order to solve the above-described problems, a sheet pressing mechanism according to the present invention includes a pressing member that presses a sheet, which undulates in a width direction orthogonal to a discharge direction of the sheet and is additionally bent, when the sheet is discharged toward a discharge tray, and the pressing member includes a first pressing region that presses a portion of the sheet other than a vertex of a mountain portion when the discharged sheet abuts against the pressing member. Further, an image forming apparatus according to the present invention is characterized by including the sheet pressing mechanism according to the present invention.

Effects of the invention

According to the present invention, it is possible to suppress the middle fold of the sheet when the discharged sheet comes into contact with the pressing member, and thus it is possible to effectively prevent the sheet from being stacked on the discharge tray with the leading end thereof bent downward.

Drawings

Fig. 1 is a schematic cross-sectional view of the image forming apparatus according to the present embodiment as viewed from the front.

Fig. 2 is a sectional view showing a sheet discharging apparatus portion of the image forming apparatus.

Fig. 3 is a perspective view of the discharge side of the sheet discharge apparatus of the image forming apparatus viewed from obliquely above.

Fig. 4 is a plan view showing a pressing member of the sheet pressing mechanism of the sheet discharge apparatus.

Fig. 5 is a side view of a main portion of the sheet discharging apparatus of the image forming apparatus as viewed from the discharging side.

Fig. 6 is a front view showing a state in which the leading end of the sheet is discharged from the discharge outlet of the sheet discharge device and abuts against the first pressing region of the pressing member.

Fig. 7 is a side view of the state shown in fig. 6 as viewed from the sheet discharging direction.

Fig. 8 is a plan view of the state shown in fig. 6.

Fig. 9 is a front view showing a state in which the leading end of the sheet reaches the second pressing region of the pressing member.

Fig. 10 is a side view of the state shown in fig. 9 as viewed from the sheet discharging direction.

Fig. 11 is a plan view of the state shown in fig. 9.

Fig. 12 is a front view showing a state where the leading end of the sheet abuts against the discharge tray.

Fig. 13 is a plan view showing another example of the pressing member.

Fig. 14 is a plan view showing still another example of the pressing member.

Fig. 15 is a plan view showing still another example of the pressing member.

Detailed Description

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. Their names and functions are also the same. Therefore, their detailed description is not repeated.

[ image Forming apparatus ]

Fig. 1 is a schematic cross-sectional view of an image forming apparatus 100 according to the present embodiment as viewed from the front. In the figure, the symbol X indicates the left-right direction when viewed from the front, and the symbols X1 and X2 indicate the left side (one side) and the right side (the other side), respectively. The symbol Y indicates a depth direction perpendicular to the left-right direction X, and the symbols Y1 and Y2 indicate a front surface side (one side) and a back surface side (the other side), respectively. The symbol Z represents the vertical direction. The image forming apparatus 100 of the present embodiment is a monochrome image forming apparatus. Image forming apparatus 100 performs image forming processing based on image data read by image reading apparatus 200 or image data transmitted from the outside. The image forming apparatus 100 may be a color image forming apparatus that forms images of multiple colors and single colors on a sheet P such as paper.

The image forming apparatus 100 includes a document feeder 108 and an image forming apparatus main body 110. The image forming apparatus main body 110 is provided with an image forming unit 102 and a sheet conveying system 103.

The image forming unit 102 includes an exposure unit 1, a developing unit 2, a photosensitive drum 3 functioning as an electrostatic latent image carrier, a cleaning unit 4, a charging device 5, and a fixing unit 7. Further, the sheet conveying system 103 includes: a paper feed tray 81, a manual paper feed tray 82, a discharge roller 31, and a discharge tray 14.

An image reading apparatus 200 for reading an image of an original G is provided on an upper portion of the image forming apparatus main body 110. The image reading apparatus 200 includes a document platen 221 on which a document G is placed. Further, a document feeding device 108 is provided above the document platen 221. In the image forming apparatus 100, an image of the original G read by the image reading apparatus 200 is conveyed to the image forming apparatus main body 110 as image data, and an image is recorded on the sheet P.

The image forming apparatus main body 110 is provided with a sheet conveyance path W1. The paper feed tray 81 or the manual paper feed tray 82 feeds the sheet P to the sheet conveyance path W1. The sheet conveying path W1 guides the sheet P to the discharge tray 14 via the transfer roller 10 and the fixing unit 7. The fixing unit 7 heat-fixes the toner image formed on the sheet P to the sheet P. Near the sheet conveying path W1,

pickup rollers

11a and 11b, a conveying roller 12a, a resist roller 13, a transfer roller 10, a heating roller 71 and a pressure roller 72 of the fixing unit 7, and a discharge roller 31 are arranged.

In the image forming apparatus 100, the sheet P fed from the paper feed tray 81 or the manual paper feed tray 82 is conveyed to the resist roller 13. Next, the sheet P is conveyed to the transfer roller 10 by the resist roller 13 at a timing to align the sheet P with the toner image on the photosensitive drum 3. The toner image on the photosensitive drum 3 is transferred to the sheet P by the transfer roller 10. Thereafter, the sheet P passes through the heating roller 71 and the pressure roller 72 of the fixing unit 7, and is discharged onto the discharge tray 14 via the conveyance roller 12a and the discharge roller 31. When image formation is performed not only on the front surface but also on the back surface of the sheet P, the sheet P is conveyed from the discharge roller 31 in the reverse direction to the reverse sheet conveying path W2. The sheet P is guided again to the resist roller 13 by reversing the front and back of the sheet P by the reversing conveyance rollers 12b to 12 b. The sheet P is discharged toward the discharge tray 14 after a toner image is formed and fixed on the back surface, similarly to the front surface.

[ sheet discharge apparatus ]

Fig. 2 is a sectional view showing a sheet discharge apparatus 300 portion of the image forming apparatus 100. Fig. 3 is a perspective view of the discharge side of the sheet discharge apparatus 300 of the image forming apparatus 100 viewed from obliquely above.

The image forming apparatus 100 further includes a sheet discharge device 300. The sheet discharge apparatus 300 discharges the sheet P conveyed from the fixing unit 7 toward the discharge tray 14. The sheet discharge device 300 includes a conveyance roller 12a, a discharge roller 31, a deflection attachment roller 32 (an example of a deflection attachment member), and a sheet pressing mechanism 301.

The conveyance roller 12a conveys the sheet P conveyed from the fixing unit 7 toward the discharge roller 31 and the deflection attachment roller 32. The discharge roller 31 discharges the sheet P conveyed from the conveyance roller 12a toward the discharge tray 14. The discharge roller 31 is composed of a pair of upper and

lower discharge rollers

31a and 31 b. The upper discharge roller 31a is smaller than the lower discharge roller 31b in the width direction H orthogonal to the discharge direction E of the sheet P. The upper discharge roller 31a faces the center portion of the lower discharge roller 31b in the width direction H. The upper discharge roller 31a serves as a drive roller, and the lower discharge roller 31b serves as a driven roller. The lower discharge roller 31b is biased toward the upper discharge roller 31a by a biasing member (not shown) such as a spring. The deflection applying rollers 32 are disposed at both ends of the lower discharge roller 31b in the width direction H. The outer diameters of the deflection applying rollers 32 to 32 are larger than the outer diameter of the lower discharging roller 31 b. Thus, the deflection adding roller 32 can undulate the sheet P in the width direction H to add deflection to the sheet P.

The sheet pressing mechanism 301 includes a pressing member 310. The pressing member 310 presses the sheet P after the deflection is applied thereto by the deflection applying roller 32 when the sheet P is discharged toward the discharge tray 14. This allows the pressing member 310 to reduce the momentum of the sheet P discharged toward the discharge tray 14.

(first embodiment)

Fig. 4 is a plan view showing a pressing member 310 of the sheet pressing mechanism 301 of the sheet discharge apparatus 300. Fig. 5 is a side view of a main portion of the sheet discharge apparatus 300 of the image forming apparatus 100 as viewed from the discharge side. Fig. 6 is a front view showing a state in which the leading end P1 of the sheet P is discharged from the discharge outlet 300a of the sheet discharge apparatus 300 and abuts against the first pressing region α of the pressing member 310. Fig. 7 is a side view of the state shown in fig. 6 as viewed from the discharge direction E of the sheet P. Fig. 8 is a plan view of the state shown in fig. 6. Further, fig. 8 illustrates a state of flexure attachment of the sheet P viewed from the discharge direction E at the left end. This is also the same in fig. 11 described later.

Fig. 9 is a front view showing a state in which the leading end P1 of the sheet P reaches the second pressing region β of the pressing member 310. Fig. 10 is a side view of the state shown in fig. 9 as viewed from the discharge direction E of the sheet P. Fig. 11 is a plan view of the state shown in fig. 9. Fig. 12 is a front view showing a state where the leading end P1 of the sheet P abuts against the discharge tray 14.

As shown in fig. 8, the pressing member 310 has a first pressing area α. The first pressing region a presses a portion (a portion of the valley Pb in this example) other than the apex Pc of the peak Pa of the sheet P when (the leading end P1 of) the discharged sheet P abuts against. The first pressing region α extends from the contact position of the sheet P by a predetermined distance in the discharge direction E of the sheet P. Here, the peak Pc of the peak Pa of the sheet P is a predetermined region in the width direction H including the peak Pt of the peak Pa on the peak Pa side, with the boundary L between the peak Pa and the valley Pb of the sheet P as a boundary. The apex Pc may be the entire region of the peak Pa.

According to the present embodiment, the first pressing region α of the pressing member 310 presses a portion of the sheet P other than the vertex Pc of the peak Pa when the discharged sheet P abuts against it. Thus, the middle fold of the sheet P when (the leading end P1 of) the discharged sheet P abuts against the pressing member 310 can be suppressed. Therefore, the leading end P1 of the sheet P can be brought into contact with the downstream side (the leading end side from the central portion) of the discharge tray 14. This can effectively prevent the sheets P from being stacked on the discharge tray 14 with the leading end P1 bent downward, for example.

However, when the pressing member 310 presses a portion other than the central region γ (see fig. 11) in the width direction H of the sheet P when the sheet P contacts the discharge tray 14, the uniformity (stackability) of the sheets P stacked on the discharge tray 14 deteriorates.

In this regard, in the present embodiment, the pressing member 310 includes the second pressing region β. The second pressing region β presses the central region γ in the width direction H of the sheet P when the sheet P is in contact with the discharge tray 14. In this way, when the sheet P is in contact with (placed on) the discharge tray 14, the second pressing region β of the pressing member 310 presses the central region γ in the width direction H of the sheet P. This can improve the consistency of the sheets P stacked on the discharge tray 14. Here, the central region γ in the width direction H of the sheet P is a predetermined region including the center in the width direction H of the sheet P.

In the present embodiment, the first pressing region α presses two or more (two in this example) portions of the sheet P other than the apex Pc of the peak Pa when the discharged sheet P abuts against each other. By doing so, it is possible to stably discharge the sheet P and suppress the middle fold of the sheet P.

In the present embodiment, the pressing member 310 includes a pair of pressing portions 311 and 311 (see fig. 4). The pair of

pressing portions

311 and 311 press two portions of the discharged sheet P other than the vertex Pc of the peak Pa when the sheet P abuts against each other. The pair of

pressing portions

311, 311 has a first pressing region α. In this way, the pressing member 310 can reliably press the two portions of the sheet P other than the vertex Pc of the peak Pa by the pair of

pressing portions

311 and 311 when the discharged sheet P abuts against each other. This enables the sheet P to be stably discharged and suppresses the middle fold of the sheet P. The pressing member 310 has a coupling portion 312 (see fig. 4). The coupling portion 312 couples the distal end portions of the pair of

pressing portions

311, 311. This enables the pair of

pressing portions

311, 311 to operate integrally. This enables the discharged sheet P to stably abut against the pressing member 310. In this example, the coupling portion 312 has a second pressing region β.

In the present embodiment, the pressing member 310 is formed in a substantially U-shape having a curved portion on the downstream side (the leading end side) as viewed from the vertical direction Z in the discharge direction E of the sheet P. In this way, the pressing member 310 can reliably press the two portions of the sheet P other than the vertex Pc of the peak Pa by the upstream side (base end side) of the substantially U-shape when the discharged sheet P abuts. This enables the sheet P to be stably discharged and suppresses the middle fold of the sheet P. The pressing member 310 can press the center or substantially the center of the sheet P by the substantially U-shaped bent portion when the sheet P contacts the discharge tray 14. This can improve the consistency of the sheets P stacked on the discharge tray 14.

In the present embodiment, as shown in fig. 4, the coupling portion 312 is inclined uniformly or substantially uniformly inward in the width direction H as it goes from the downstream side end portions (tip end portions) of the pair of

pressing portions

311, 311 toward the downstream side in the discharge direction E of the sheet P. The coupling portion 312 is connected to the pair of

pressing portions

311, 311 such that a center portion or a substantially center portion in the width direction H is a vertex. The pair of

pressing portions

311, 311 further includes: base portions 311a, and inclined

portions

311b, 311 b. The

bases

311a, 311a are arranged in parallel or substantially parallel to the discharge direction E of the sheet P. The

inclined portions

311b, 311b are provided between the

base portions

311a, 311a and the coupling portion 312. The

inclined portions

311b, 311b are inclined at an inclination angle smaller than the inclination angle of the coupling portion 312 or substantially at an equal angle gradually inward in the width direction H as they go from the

base portions

311a, 311a to the coupling portion 312. The pressing member 310 is formed by a pair of pressing portions 311 and a coupling portion 312 ー. This enables the pressing member 310 to be a single member.

In the present embodiment, the distal end 312a of the coupling portion 312 is located at a position that presses the central portion or substantially the central portion of the sheet P in the width direction H. By doing so, the sheets P stacked on the discharge tray 14 can be reliably integrated.

In the present embodiment, the pressing member 310 is configured to rotate about an axis Q along the width direction H. This allows the pressing member 310 to smoothly rotate in the vertical direction Z. This enables the discharged sheet P to reliably abut against the pressing member 310. Specifically, at the upstream end (base end) of the pressing member 310, the engaging

convex portions

310a and 310a (see fig. 4 and 6) protrude outward in the width direction

H. Engagement holes

302a and 302a (see fig. 6) are formed through the sheet discharge apparatus main body 302 (outer cover) (see fig. 6) in the width direction H.

The engaging holes

302a, 302a are engaged with the engaging

protrusions

310a, 310a so as to be rotatable about the axis Q.

In the present embodiment, the discharge tray 14 (see fig. 2, 6, and 9) includes a first tray part 141 and a second tray part 142. The first tray portion 141 is located on the upstream side (base end side) of the discharge tray 14 in the discharge direction E of the sheet P. The second tray part is connected to the downstream side of the first tray part 141. The first tray part 141 and the second tray part 142 are integrally formed. The first tray part 141 is inclined such that the downstream side (tip side) is higher than the upstream side. The second tray part 142 is horizontal or substantially horizontal, or inclined such that the downstream side is at a lower angle than the upstream side than the first tray part 141.

However, in the discharge tray 14, when the sheet P is folded in the middle, the sheet P is placed on the discharge tray 14 while moving on the first tray part 141 in a state where the leading edge P1 of the sheet P is in contact with the first tray part 141. At this time, if the leading end P1 of the sheet P does not move smoothly on the first tray portion 141, the sheet P is stacked on the discharge tray 14 in a state where the leading end P1 is bent downward, for example. On the other hand, when the middle fold of the sheet P is not generated, the leading end P1 of the sheet P can be brought into contact with the second tray section 142. Thus, for example, a situation where the sheets P are stacked on the discharge tray 14 in a state where the leading end P1 is bent downward does not occur or hardly occurs.

In this regard, in the present embodiment, as shown in fig. 12, the first pressing region α of the pressing member 310 when the sheet P contacts the discharge tray 14 extends up to the corresponding region δ corresponding to the second tray section 142 in the discharge direction E of the sheet P. In this way, a state in which a portion other than the vertex Pc of the peak Pa of the sheet P is pressed by the first pressing region α at the time of discharging the sheet P can be secured to the corresponding region δ corresponding to the second tray part 142. Therefore, the leading end P1 of the sheet P can be brought into contact with the second tray portion 142. In this way, the leading end P1 of the sheet P can be smoothly moved in the second tray portion 142. Thus, for example, a case where the sheet P is stacked on the discharge tray 14 in a state where the leading end P1 is bent downward does not occur or hardly occurs.

(second embodiment)

Fig. 13 is a plan view showing another example of the pressing member 310. The pressing member 310 shown in fig. 13 is a member formed by removing the connecting portion 312 from the pressing member 310 of the first embodiment and forming a pair of

pressing portions

311, 311 in a straight line (rod shape) along the discharge direction E of the sheet P. The pair of

pressing portions

311, 311 of the pressing member 310 shown in fig. 13 has a first pressing region α. By doing so, it is possible to stably discharge the sheet P and suppress the middle fold of the sheet P.

(third embodiment)

Fig. 14 is a plan view showing still another example of the pressing member 310. The pressing member 310 shown in fig. 14 is a member in which a coupling portion 312 is provided to the pressing member 310 of the second embodiment. The coupling portion 312 of the pressing member 310 shown in fig. 14 is formed linearly at right angles or substantially at right angles to the pair of

pressing portions

311, 311. This enables the pair of

pressing portions

311, 311 to operate integrally. This enables the discharged sheet P to stably abut against the pressing member 310.

(fourth embodiment)

Fig. 15 is a plan view showing still another example of the pressing member 310. The pressing member 310 shown in fig. 15 is a member in which a protruding portion 312b is provided at the center in the width direction H of the coupling portion 312 in the pressing member 310 of the third embodiment. The protruding portion 312b of the pressing member 310 shown in fig. 15 has a second pressing region β. The projection 312b extends along the discharge direction E of the sheet P. In this way, when the sheet P comes into contact with the discharge tray 14, the central region γ (see fig. 11) in the width direction H of the sheet P can be pressed by the protruding portion 312 b. This can improve the consistency of the sheets P stacked on the discharge tray 14.

(other embodiments)

In the present embodiment, the pressing portions of the pressing member are paired (two), but one, or three or more pressing portions may be provided. In the present embodiment, the deflection adding member is a deflection adding roller, but may be a deflection adding guide.

The present invention is not limited to the embodiments described above, and can be implemented in other various forms. Therefore, all aspects of the above embodiments are merely exemplary, and the present invention is not to be construed in a limited manner. The scope of the invention is indicated by the claims, which are not at all limited by the text of the description. Further, all changes and modifications that fall within the equivalent scope of the claims fall within the scope of the present invention.

Description of the symbols

100 image forming apparatus

14 discharge tray

141 first tray part

142 second tray part

300 sheet discharge device

300a discharge outlet

301 sheet pressing mechanism

302 sheet discharge apparatus main body

31 discharge roller

310 pressing component

311 pressing part

311a base

311b inclined part

312 connecting part

312a front end

312b projection

31a upper discharge roller

31b lower discharge roller

32 flexure attaching roller (an example of flexure attaching part)

E discharge direction

H width direction

L line of demarcation

P sheet

P1 front end

P2 rear end

Pa mountain part

Pb trough

Pc vertex part

Pt apex

Axis Q

Alpha first pressing area

Beta second compression area

Central region of gamma

Delta corresponding region

Claims

1. A sheet discharging device having a deflection adding member that adds a deflection to a discharged sheet and a pressing member that presses the sheet undulated by the deflection adding member in a width direction orthogonal to a discharging direction of the sheet when the sheet is discharged toward a discharge tray, the sheet discharging device being characterized in that,

the pressing member has a first pressing region that presses a portion of the sheet other than a peak portion of a mountain portion of the sheet that undulates in the width direction when the discharged sheet comes into contact with the pressing member.

2. The sheet discharging device according to claim 1,

the pressing member has a second pressing region that presses a central region in the width direction of the sheet when the sheet is in contact with the discharge tray.

3. The sheet discharging device according to claim 1 or claim 2,

the first pressing region presses two or more portions of the sheet other than a vertex of a mountain portion of the sheet when the discharged sheet abuts against the first pressing region.

4. The sheet discharging device according to claim 1 or claim 2,

the pressing member includes: a pair of pressing portions that press two portions of the sheet other than a vertex of the mountain portion when the discharged sheet abuts against each other; and a connecting portion that connects the distal end portions of the pair of pressing portions.

5. The sheet discharging device according to claim 1 or claim 2,

the pressing member is formed in a substantially U-shape having a downstream side formed as a curved portion when viewed from a vertical direction in a sheet discharge direction.

6. The sheet discharging device according to claim 1 or claim 2,

the pressing member is configured to rotate about an axis along the width direction.

7. An image forming apparatus is characterized by comprising:

the sheet discharge apparatus according to any one of claims 1 to 6.

8. The image forming apparatus according to claim 7,

the discharge tray includes a first tray portion on an upstream side in a discharge direction of the sheet, and a second tray portion continuously provided on a downstream side of the first tray portion,

the first tray part is inclined so that the downstream side is higher than the upstream side,

the second tray part is horizontal or approximately horizontal, or is inclined such that the downstream side is higher than the upstream side by a smaller angle than the first tray part,

the first pressing region of the pressing member when the sheet is in contact with the discharge tray extends up to a region corresponding to the second tray portion in the discharge direction of the sheet.