JP7171815B2 - Sheet conveying device and image forming device - Google Patents

Description

The present invention relates to a sheet conveying device for conveying a sheet in an image forming apparatus such as a copier, printer, facsimile, etc., and an image forming apparatus having the sheet conveying device.

2. Description of the Related Art In recent years, image forming apparatuses such as printers and copiers have been proposed that have a configuration capable of stably conveying sheets when performing printing (see Patent Document 1).

JP 2007-131455 A

In the prior art, no consideration has been given to the fact that the guide surface of a guide may be damaged by contact with another guide, resulting in defective transport.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sheet conveying device and an image forming apparatus capable of preventing the guide surface of a guide from being damaged .

The sheet conveying apparatus of the present invention includes a guide member that guides a sheet, and a resin sheet that is provided on the guide member and protrudes downstream in the sheet conveying direction from a downstream end of the guide member. and a rotatable second guide provided downstream of the first guide in the sheet conveying direction and including a guide surface with which the sheet contacts, wherein the first guide and the second The resin sheet can contact the second guide so that the guide member does not contact the guide surface of the second guide regardless of rotation of the second guide, and the resin sheet can contact the second guide. The resin sheet is a member that prevents the guide surface of the second guide from being damaged when coming into contact with the second guide .

According to the present invention, it is possible to prevent the guide surface of the guide from being damaged .

1 is a cross-sectional view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention; FIG. 3A is a sectional view in the conveying direction of the sheet conveying device according to the present embodiment, and FIG. 3B is a sectional view in the conveying direction of the sheet conveying device showing a state different from that of FIG. 4A and 4B are cross-sectional views in the conveying direction of the sheet conveying device showing different states; (a) and (b) are detailed views of the vicinity of the curved portion of FIG. 2(a) in the present embodiment. (a) is a cross-sectional view in the conveying direction of a sheet conveying device in a comparative example, and (b) is a cross-sectional view in the conveying direction of the sheet conveying device showing a state different from (a). (a) is a cross-sectional view in the conveying direction of a sheet conveying device in a comparative example, and (b) is a cross-sectional view in the conveying direction of the sheet conveying device showing a state different from (a).

An image forming apparatus such as a copying machine and a printer will be described below as an example with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the following embodiments should be appropriately changed according to the configuration of the device to which the present invention is applied and various conditions. They are not intended to limit the scope of the invention only to them.

FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus 90 according to this embodiment. In this embodiment, a color image forming apparatus using an electrophotographic system is used. In recent years, this color image forming apparatus has the advantages of adaptability to a wide variety of sheets and excellent print productivity. Arranged intermediate transfer tandem system is mainstream.

As shown in FIG. 1, the image forming apparatus 90 is connected to the image forming apparatus main body 100 and the image forming apparatus main body 100 for stacking a large amount of sheets S and feeding them to the image forming apparatus main body 100. A paper deck 101 is provided. The paper deck 101 constitutes a sheet supply unit that supplies sheets. A reader unit 21 having a scanning optical system for reading an image is arranged in the upper part of the image forming apparatus main body 100 . Below the reader section 21, image forming units 1Y, 1M, 1C, and 1K arranged along the rotation direction of the intermediate transfer belt 31 are arranged. These image forming units 1Y, 1M, 1C, and 1K correspond to yellow (Y), magenta (M), cyan (C), and black (Bk), respectively.

In the lower part of the image forming apparatus main body 100, paper feed cassettes 61, 62, 63, and 64 are arranged vertically in FIG. , 72, 73, 74 and separate conveying means 86, 87, 88, 89. The paper feed cassettes 61 to 64 are configured in a front loading type in which the sheets S are accommodated and mounted so as to be pulled out from the front side (front side in FIG. 1) of the image forming apparatus main body 100 .

[Sheet Conveying Process]
In the image forming apparatus 90, the sheets S are stacked in the paper feed cassettes 61 to 64 of the image forming apparatus main body 100, respectively, and are picked up by the corresponding pickup rollers 71 to 74 in the image forming units 1Y to 1K. The sheet is fed in accordance with the image forming timing of . The sheet S sent out by each of the pickup rollers 71 to 74 passes through the vertical conveying path 81 and is conveyed to the registration roller pair 76 .

The registration roller pair 76 has a function of forming a loop by abutting the sheet S conveyed from the sheet feeding cassettes 61 to 64, thereby making the leading edge of the sheet S follow and correcting the skew. Further, the registration roller pair 76 has a function of conveying the sheet S to the secondary transfer portion at a predetermined timing in accordance with the toner image carried on the intermediate transfer belt 31 after executing the skew correction. The secondary transfer portion is a secondary transfer nip portion N2 formed by the secondary transfer inner roller 32 and the secondary transfer outer roller 41 facing each other. A toner image is secondarily transferred thereon.

After that, the sheet S is conveyed to the fixing device 5 by the pre-fixing conveying device 42 . The fixing device 5 is configured to melt and fix the toner image onto the sheet S by applying a predetermined pressure from an opposing roller or belt or the like and a heating effect generally from a heat source such as a heater. Image forming means for forming an image on the conveyed sheet S by the image forming portion 1 (1Y, 1M, 1C, 1K), the secondary transfer nip portion (secondary transfer portion) N2, the fixing device 5, and the like. Configured.

In the case of single-sided image forming mode specified by the user, the paper is discharged from the discharge port 50 to the outside of the apparatus. On the other hand, in the double-sided image forming mode, the sheet S is sent again to the image forming units 1Y to 1K through the reversing path 52 and the double-sided conveying path 85 by the path switching means 51 . Reference numeral 77 in FIG. 1 denotes a conveying roller pair that conveys the sheet S fed from each of the pickup rollers 71 to 74 to the registration roller pair 76. As shown in FIG.

On the other hand, as shown in FIG. 1, the paper deck 101 includes sheet storage units 92, 93, and 94 arranged in the vertical direction in the deck, and suction transport units arranged corresponding to the respective sheet storage units 92 to 94. 201 , 202 , 203 and drawing roller pairs 95 , 96 , 97 . In the present embodiment, a method of sucking the sheet S to the conveying belt by negative pressure of air and separating and conveying the sheet S is adopted as the attracting conveying unit. The paper deck 101 includes a conveying roller pair 301 that conveys the sheet S drawn and conveyed through the drawing roller pairs 95 to 97 further downstream. Further, the paper deck 101 includes a discharge roller pair 302 for sending the sheet S sent by the conveying roller pair 301 to the apparatus main body entrance roller pair 91 on the image forming apparatus main body 100 side. A sheet conveying device 65 having a curved conveying path 80 communicating with the portion of the apparatus main body entrance roller pair 91 of the image forming apparatus main body 100 is provided downstream of the discharge roller pair 302 . The sheet conveying device 65 is located near a connection point of the paper deck (sheet supply unit) 101 with the image forming apparatus main body 100 .

[Sheet Conveying Device]
Next, the sheet conveying device 65 according to this embodiment will be described with reference to FIGS. 2(a) and 2(b) and FIGS. 2A and 2B are cross-sectional views taken along the sheet conveying direction of the sheet conveying device 65 according to this embodiment. 4 shows a transport path for transferring sheets fed from the feeding unit of the paper deck 101. FIG. FIGS. 3A and 3B are cross-sectional views taken along the conveying direction showing the sheet conveying device 65 according to the present embodiment in different states.

As shown in FIGS. 2A and 2B, the sheet conveying device 65 in this embodiment includes a first conveying guide pair 310 arranged upstream in the sheet conveying direction and a second conveying guide pair 310 arranged downstream. A pair 320 is provided. In the first conveying guide pair 310, a first outer guide 311 and a first inner guide 312 are arranged facing each other with a gap therebetween so that the sheet S can be guided. Also, in the second conveying guide pair 320, a second outer guide 321 and a second inner guide 322 are arranged facing each other with a gap therebetween. The second transport guide pair 320 communicates with the first transport guide pair 310 at a predetermined angle α, and the second transport guide pair 320 and the first transport guide pair 310 form a curved transport path 80 to The sheet S guided by the guide pair 310 can be guided. A sheet transfer section 84 is formed between the first conveying guide pair 310 and the second conveying guide pair 320 .

As shown in FIG. 2A, a second conveying guide pair 320 is provided at the sheet discharging portion of the paper deck 101 so as to correspond to the apparatus main body inlet roller pair 91 arranged at the sheet receiving portion of the image forming apparatus main body 100 side. are placed. On the paper deck 101 side, a curved guide pair 330 composed of a curved lower guide 331 and a curved upper guide 332 fixedly supported at opposing positions between the transport roller pair 301 and the discharge roller pair 302 is provided. are placed.

The conveying roller pair 301 is composed of a lower roller 301a and an upper roller 301b. Also, the discharge roller pair 302 is composed of an inner roller 302a and an outer roller 302b. In addition, in this embodiment, as the material of guides such as the curved guide pair 330, the first transfer guide pair 310, and the second transfer guide pair 320, a stainless steel material having good abrasion resistance is used.

As shown in FIG. 3A, the second conveying guide pair 320 is provided near the sheet delivery section 84 between the first conveying guide pair 310 (provided on the paper deck side). It is fixed to a support plate 53 that is rotatably supported with a driving shaft 401 as a fulcrum. As a result, the second transport guide pair 320 is rotatably supported with respect to the paper deck (apparatus main body) 101 . Therefore, by rotating the second conveying guide pair 320 in accordance with the difference in height between the image forming apparatus main body 100 and the paper deck 101 connected thereto when the image forming apparatus main body 100 and the paper deck 101 connected thereto are installed, the paper deck 101 can be removed from the image forming apparatus main body. Smooth handover of sheets to 100 is possible. The rotation range of the support plate 53 is limited to a certain angle by a stopper (not shown).

As shown in FIG. 3B, the door portion 54 is rotatably supported near the sheet delivery portion 84 with a second rotation shaft 402 provided on the paper deck 101 as a fulcrum. The door portion 54 is provided with a first outer guide 311 , a curved lower guide 331 , and an outer roller 302 b of the discharge roller pair 302 . As a result, when a jam (paper jam) occurs in the curved transport path 80, the user opens the door portion 54 so that the first outer guide 311 and the curved lower guide 331 move, and the first transport guide pair 310 moves. and curved guide pair 330 are opened, allowing the sheet to be removed.

A sheet S fed by any one of the suction conveying units 201, 202, and 203 shown in FIG. The leading edge of the sheet S reaches the second conveying guide pair 320 (not shown in FIG. 1). As shown in FIG. 2( a ), the first outer guide 311 is positioned outside the curve of the curved transport path 80 in the first transport guide pair 310 . The first outer guide 311 is bent from the upstream portion of the first outer guide 311 at a predetermined angle α with respect to the second outer guide 321 positioned outside the curve of the curved conveying path 80 in the second conveying guide pair 320 . It has an extended bent extension portion 311a. In addition, as shown in FIG. 4B, the bent and extended portion 311a of the first outer guide 311 is bent at _a bending angle α1.

As shown in FIGS. 2A and 2B, the first inner guide 312 is positioned inside the curve of the curved conveying path 80 in the first conveying guide pair 310 . A downstream end of the bent and extended portion 311a in the sheet conveying direction A extends toward the second outer guide 321 beyond a position where it intersects an extension line B that extends linearly along the inner surface of the first inner guide 312. . This extension line B is a sheet conveying trajectory when a sheet with high rigidity such as thick paper is conveyed by the discharge roller pair 302 . That is, a sheet with high rigidity such as thick paper is conveyed along the inner surface of the first inner guide 312 .

The bent and extended portion 311a of the first outer guide 311 is bent and extended at a predetermined angle α with respect to the second outer guide 321 positioned outside the curve of the curved conveying path 80 of the second conveying guide pair 320 . is set. As a result, a sheet having a high rigidity such as a cardboard or an envelope is conveyed while being bent in stages, so that the sheet can be stably conveyed.

Here, as shown in FIGS. 4A and 4B, the bending angle α1 of the bent extension portion 311a in the _first outer guide 311 and the angle formed by the elastic guide member 313 and the second outer guide 321 are α2 _are set to angles that are substantially equal to each other. As a result, the leading edge of the conveyed sheet S inevitably comes into contact with the bent and extended portion 311 a , and the traveling direction of the sheet S is changed along the conveying surface of the sheet delivery portion 84 .

An elastic guide member 313 extending downstream in the sheet conveying direction A and capable of elastically contacting the inner surface of the second outer guide 321 is attached to the bent and extending portion 311a. The elastic guide member 313 is fixedly arranged at the downstream end portion in the sheet conveying direction A of the bent and extended portion 311a. In this embodiment, the elastic guide member 313 is made of a thin spring stainless steel plate having lower rigidity than the stainless steel material used for each transport guide.

Further, as shown in FIGS. 4A and 4B, on the surface (back surface) of the elastic guide member 313 on the side opposite to the conveying surface, a second outer guide member extending further toward the downstream end in the sheet conveying direction A is provided. A sheet-like member 314 made of resin (plastic) is attached to the inner surface of 321 . A downstream end of the sheet member 314 in the sheet conveying direction A protrudes further toward the second outer guide than the downstream end of the elastic guide member 313 .

Therefore, when the support plate 53 supporting the second conveying guide pair 320 shown in FIG. 3A and the door portion 54 supporting the first outer guide 311 shown in FIG. become. That is, during this rotation, the elastic guide member 313 contacts the second outer guide 321 via the sheet-like member 314 and is elastically deformed. As a result, the elastic guide member 313 can more stably and smoothly transfer the sheet S such as a cardboard or an envelope from the first conveying guide pair 310 to the second conveying guide pair 320 . Furthermore, since the sheet-like member 314 prevents the elastic guide member 313 from directly contacting the second outer guide 321, damage to the second outer guide 321 is reduced, and transportation failure due to scratches on the second outer guide 321 is prevented. can be prevented.

In this case, the leading end of the sheet S smoothly comes into contact with the bending and extending portion 311a and the elastic guide member 313 in this order immediately before contacting the second outer guide 321, and then gently bends while passing through the sheet-like member 314 to the second outer guide 321. 2 contacts the outer guide 321; Since the predetermined angle α (see FIG. 2A) when the sheet S comes into contact with the second outer guide 321 is a small angle, it is possible to sufficiently soften the impact of the contact of the conveyed sheet S.

Here, a comparative example for this embodiment will be described with reference to FIGS. 5A is a sectional view in the conveying direction of a sheet conveying device in a comparative example, and FIG. 5B is a sectional view in the conveying direction of the sheet conveying device in a state different from that of FIG. 5A. FIG. 6A is a cross-sectional view in the conveying direction of a sheet conveying device in a comparative example, and FIG. 6B is a cross-sectional view in the conveying direction of the sheet conveying device in a state different from that in FIG. 6A.

That is, as shown in FIG. 5(a), the curved conveying path 80 has the transfer of the first conveying guide pair 310 and the second conveying guide pair 320, and the curved conveying path 80 is formed as shown in FIG. 5(b). In the configuration in which the guide is rotatable around the shaft, the following is required. In other words, it is necessary to position the guide ends of the bent and extended portion 311a and the like in the sheet delivery portion within a range where the guides do not interfere with each other during swinging.

Therefore, as shown in FIG. 5A, the leading edge of the sheet S conveyed in the sheet conveying direction A comes into contact with the second outer guide 321 at a relatively large contact angle β. For this reason, when the sheet S is thick paper or an envelope having high rigidity, the transport resistance increases abruptly, causing a problem that the size of the transport driving motor (not shown) increases.

Further, when the elastic guide member 313 is simply attached to extend the lower end portion 311b in order to allow interference between the guides in the curved conveying path 80 as shown in FIG. 6A, the following results. That is, as shown in FIG. 6B, the elastic guide member 313 is deformed so as to be simply bent due to the high rigidity of the sheet S during conveyance. becomes larger. Therefore, it is insufficient as a countermeasure for reducing the contact angle γ.

On the other hand, in this embodiment, the problems described with reference to FIGS. 5(a), (b) and FIGS. 6(a), (b) can be resolved. That is, regarding the conveyance of a sheet such as thick paper with high rigidity, in a configuration in which the sheet is delivered on the curved conveyance path 80, the sheet can be conveyed at a curved angle that allows conveyance of plain paper and with a relatively low conveyance load. becomes. This makes it possible to provide a small and stable sheet conveying device 65 . Further, it is possible to suppress the transport load of the sheet S at the time of transporting the sheet, prevent defective transport in the curved transport path 80, and avoid an increase in the size of the transport motor (not shown). Become. Furthermore, it is possible to prevent the collision sound of the leading edge of the sheet.

Therefore, according to the present embodiment, the sheet can be conveyed with a relatively low conveying load at a curvature angle that can convey plain paper having a lower rigidity than thick paper, and the stable sheet conveying device 65 can be provided.

In the present embodiment, the first conveying guide pair 310, the second conveying guide pair 320, the curved guide pair 330, and other conveying guides are made of stainless steel, and the elastic guide member 313 is made of a spring stainless thin plate. is possible, but not limited to this. For example, a similar effect can be achieved by using an electrogalvanized steel sheet as the material of the transport guide and a polyester film as the material of the elastic guide member 313 . Also, the sheet member 314 can be made of a polyester film or the like.

1, 5, N2... Image forming section, fixing device, secondary transfer nip section (image forming means)/65... Sheet conveying device/80... Curved conveying path/84... Sheet delivery section/90... Image forming apparatus/100... Image forming apparatus main body/101 Paper deck (apparatus main body, sheet supply unit)/310 First conveying guide pair/311 First outer guide/311a Bending and extending portion/312 First inner guide/313 Elasticity Guide member/314 Sheet-shaped member/320 Second conveying guide pair/321 Second outer guide/401 First rotating shaft/402 Second rotating shaft/B Extension line/S Sheet/α …predetermined angle

Claims (4)

a rotatable first guide having a guide member that guides a sheet; and a resin sheet that is provided on the guide member and protrudes downstream in a sheet conveying direction from a downstream end of the guide member;
a rotatable second guide provided downstream of the first guide in the sheet conveying direction, including a guide surface in contact with the sheet, and
The resin sheet can contact the second guide so that the guide member does not contact the guide surface of the second guide regardless of rotation of the first guide and the second guide. Ri ,
When the resin sheet contacts the second guide, the resin sheet is a member that prevents the guide surface of the second guide from being damaged.
A sheet conveying device characterized by: The resin sheet is made of a material that is less likely to damage the guide surface of the second guide than the guide member.
2. The sheet conveying apparatus according to claim 1, wherein: A facing guide provided at a position facing the second guide for guiding the sheet,
A gap is formed between the resin sheet and the counter guide so that the sheet can be conveyed when the sheet is positioned at the sheet conveying position.
3. The sheet conveying apparatus according to claim 1, wherein: a sheet feeding means for feeding a sheet;
image forming means for forming an image on the sheet fed by the sheet feeding means;
A sheet conveying device according to any one of claims 1 to 3,
The first guide and the second guide are arranged on a sheet conveying path from the feeding means to the image forming means,
An image forming apparatus characterized by:

Images