JP3398237B2 - Paper transport device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper transport device provided for transporting paper such as recording paper in an image forming apparatus such as a facsimile machine. 2. Description of the Related Art Some facsimile apparatuses use a recording sheet made of cut paper to record a received image. Further, in this type of facsimile apparatus,
In order to reduce the size of the apparatus, a configuration was adopted in which recording paper stacked and housed in a paper cassette was transported to a process unit that performs image formation by electrophotography via a so-called U-turn-shaped transport path. There is something. In a facsimile apparatus of this type, a process unit is disposed above a paper cassette, and the recording paper fed from the paper cassette is conveyed in a U-turn, and is directed to the process unit above the paper cassette. By providing the transport path, the length of the apparatus body of the facsimile apparatus can be reduced. In general, a feeder roller and a pinch roller that comes into contact with the feeder roller are provided between the exit of the U-turn type transport path and the process unit, and the recording paper sent from the exit of the U-turn type transport path is provided. It is transported to the process unit. FIG. 4 shows the overall structure of a facsimile apparatus of this type, and FIG. 5 (a) shows an enlarged view of a recording paper transport device provided in the facsimile apparatus. In FIG. 1, reference numeral 1 denotes an apparatus main body of a facsimile apparatus, 2 denotes a paper cassette which is provided at the bottom of the apparatus main body 1 so as to be able to be taken in and out, and a plurality of recording papers P made of cut paper are stacked, and 3 is stacked on the paper cassette 2. A paper feed roller 4 for feeding out the recording paper P is a process unit disposed on the upper side of the paper cassette 2 for forming an image by an electrophotographic method. [0005] Reference numeral 5 denotes a U-turn type recording paper conveyance path, which conveys the recording paper P fed from the paper cassette 2 toward the lower side of the process unit 4 while drawing an arc upward. Reference numeral 6 denotes an outlet for receiving the recording paper P conveyed in the conveyance path 5 and sending it out toward the process unit 4 in the horizontal direction. Reference numeral 6a denotes a receiving surface of the recording paper P at the outlet 6. Reference numerals 7 and 8 denote conveying rollers which are arranged at the entrance of the conveying passage 5 and are rotated by obtaining a rotational driving force.
Reference numeral 9 denotes a feed roller provided on the front side of the outlet section 5 and rotated by obtaining a rotational driving force. Reference numeral 10 denotes a feed roller positioned below the feed roller 9 and driven by the rotation of the feed roller 9 pressed against the feed roller. It is a pinch roller that is rotated. Here, conventionally, the contact point O between the feed roller 9 and the pinch roller 10 is located at the receiving surface 6 for receiving the recording paper P at the exit portion 6 of the transport path 5 as shown in FIG.
It is set at the same height as a. The recording paper P accommodated in the paper cassette 2 is sequentially fed out by the rotating paper feed roller 3, and then transported by the rotating transport rollers 7 and 8 through the transport path 5 having a U-turn shape to the outlet. 6 is transported. Further, the recording paper P is conveyed to the process unit 4 through the space between the rotating feed roller 9 and the contact portion of the pinch roller 10 to form a toner image. In FIG. 1, reference numeral 11 denotes a fixing unit for fixing the toner image on the recording paper P, and reference numeral 12 denotes a document reading unit for reading the contents of the document for transmission. [0010] Such a conventional recording paper transport section has the following problems. The recording paper P fed out of the paper cassette 2
Is forcibly curved in the process of being conveyed to the outlet portion 6 through the U-shaped conveyance path 5, and thus has a curl of curving downward and wrapping around. For this reason, when the recording paper P having the curl is sent out from the exit portion 6 of the transport path 5, it may not move in the horizontal direction but may move in the downward direction and be sent out. However, the contact point O between the feed roller 9 and the pinch roller 10 is set at the same height as the receiving surface 6a for receiving the recording paper P at the outlet 6 of the transport path 5. For this reason, as shown in FIG. 5B, the recording paper P moved downward from the outlet 6 of the transport path 5 and sent out does not enter the contact point O between the feed roller 9 and the pinch roller 10. , Comes into contact with the outer peripheral surface of the pinch roller 10. However, since the pinch roller 10 rotates by following the feed roller 9 without having any rotational force, the recording paper P contacting the outer peripheral surface of the pinch roller 10 is rotated only by the rotational force of the pinch roller 10. It is often difficult to move to the contact point O between the feed roller 9 and the pinch roller 10. In this case, the recording paper P cannot be conveyed to the process unit 4 by the feed roller 9 and the pinch roller 10, and stops before the feed roller 9 and the pinch roller 10, resulting in a so-called paper jam. The present invention has been made in view of the above circumstances, and the paper fed from a cassette, conveyed through a conveyance path, and sent out in a curled state stops before a feed roller and a pinch roller. It is an object of the present invention to provide a paper transport device that can prevent paper jams from occurring. According to a first aspect of the present invention, there is provided a sheet transporting apparatus comprising: a sheet cassette on which sheets made of cut sheets are stacked; a sheet feeding roller for feeding out the sheets stacked on the sheet cassette; A conveying passage having a curved passage portion through which the paper fed from the paper cassette is conveyed, and an outlet portion for receiving and sending the paper conveyed in the passage portion;
A feed roller provided in front of the outlet portion of the transport passage and rotated by obtaining a rotational driving force, and a sheet pressed and contacted by the feed roller, rotated by the rotation of the feed roller, and rotated by the rotation of the feed roller, and fed from the outlet portion And a pinch roller for conveying the sheet along with the feed roller, and a point where the feed roller and the pinch roller come into contact with each other is a curved path of the conveyance path with respect to a sheet receiving surface at the outlet of the conveyance path. Paper is conveyed through the section and is provided with a curl, is located on the side in the direction of moving along the curl when being sent out from the exit portion, and a point where the feed roller and the pinch roller come into contact with each other. The distance between the outlet and the surface receiving the sheet is at least as large as the thickness of the sheet. According to the first aspect of the present invention, the paper fed from the paper cassette is forcedly curved in the process of being transported to the outlet through the transport path having the curved portion, and thus has a curl. Is given. For this reason, the curled paper moves in the winding direction of the curl when being fed from the exit of the transport path. Here, the point at which the feed roller and the pinch roller come into contact with each other is such that the curl-imparted sheet is fed out from the exit portion of the sheet conveying path when the sheet is fed from the exit portion. It is located on the side of the direction along which it moves. Therefore, even if the paper with the curl is moved from the outlet of the transport path in the direction of winding of the curl and is sent out, the paper does not contact the outer circumferential surface of the pinch roller before the outer circumferential surface of the feed roller. Abut. Since the feed roller is rotating with its own rotational driving force, the paper abutting on the outer peripheral surface is surely moved to the contact point between the feed roller and the pinch roller, and the contact portion between the feed roller and the pinch roller is contacted. Can be transported through. Therefore, it is possible to prevent the paper fed from the cassette, conveyed through the conveyance path and sent out, from stopping at the feed roller and the pinch roller and causing a paper jam. An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows the overall structure of a facsimile apparatus of this type, FIG. 2 shows a cross section of a recording paper conveying apparatus provided in the facsimile apparatus, and FIG. 3 shows an exploded perspective view of the recording paper conveying apparatus. I have. In the figure, reference numeral 21 denotes an apparatus main body, which is a lower main body 2.
2 and an upper main body 23. The lower main body 22 includes a base frame 24, a mechanical frame 25 mounted on the upper portion of the base frame 24, a back panel frame 26, and an upper guide 27, and further includes a cover 28 surrounding the outer shell of these components. I have. The upper main body 23 is provided on the lower main body 22 so as to be vertically rotatable. Below the base frame 24 of the lower main body 22, a paper cassette 29 is disposed so as to be able to be taken in and out through an opening 30 formed in the base frame 24. Are stacked and accommodated. A paper feed roller 31 is provided above the rear end of the paper cassette 29 in the insertion direction. The paper feed roller 31 is rotated by a rotation driving device (not shown) provided on the lower main body 22 to sequentially feed out the recording papers P stacked on the paper cassette 29 one by one from the uppermost layer in the arrow direction. A process unit 32 is arranged above the center of the paper cassette 29 and is held by the mechanical frame 25. The process unit 32 forms an image on the recording paper P by an electrophotographic method.
The upper main body 2 includes a photosensitive drum 33 and a developing device.
A toner image is formed by the developing device on the outer peripheral surface of the photosensitive drum 33 on which the electrostatic latent image has been formed by the exposure device 44 provided on the recording paper P, and this toner image is formed on the recording paper P. Numeral 34 denotes a conveyance path for recording paper, which is a line which flows in a horizontal direction toward the lower side of the process unit 32 after drawing an arc of the recording paper P fed from the paper cassette 29 upward. What to draw, base frame 24,
It is configured by combining a back panel frame 26 and an upper guide 27. That is, the passage forming portion 24a of the base frame 24 forms an inner side portion of the transport passage 34, and the passage forming portion 24a and the passage forming portion 2
Back panel frame 26 attached to rear of 4a
Constitutes an inlet portion 34a, and an outlet portion 34b is constituted by the passage constituting portion 24a and the upper guide 27 attached to the upper portion of the passage constituting portion 24a. This entrance 3
A curved passage portion 34c is formed between 4a and the outlet portion 34b. The entrance 34a rises from a position close to the paper cassette 29. The outlet portion 34b is positioned horizontally toward the lower side of the process unit 32, and has a receiving surface 35 for receiving the recording paper P conveyed by the passage forming portion 24a. At the entrance 34a of the transfer passage 34, a transfer roller 36 held by the passage forming portion 24a and a transfer roller 37 held by the back panel frame 26 are provided in contact with each other. It is designed to be rotated by a rotation drive device that does not. A feed roller 38 and a pinch roller 39 are provided between the outlet 34b of the transport passage 34 and the process unit 4. The feed roller 38 is located on the upper side, and the pinch roller 39 is located on the lower side of the feed roller 38. The feed roller 38 is rotatably supported by the mechanical frame 25. Pinch roller 3
Numeral 9 is rotatably supported by a shaft 40 which is disposed in the passage constituting portion 24a of the base frame 24 so as to be able to move up and down. Therefore, the pinch roller 39 is always in contact with the feed roller 38. Here, the point O where the feed roller 38 and the pinch roller 39 come into contact with each other is a receiving surface 3 for receiving the recording paper P at the outlet 34b of the transport path 34 as shown in FIG.
5 is located on the lower side with a distance S. That is, the point O where the feed roller 38 and the pinch roller 39 come into contact with each other is at the outlet 3 of the transport path 34.
4b, it is located below the surface 35 for receiving the recording paper P, which is the paper in FIG. Further, the point O where the feed roller 38 and the pinch roller 39 come into contact with each other is defined by the conveyance path 3 at the exit 35 of the conveyance path 34 with respect to the surface receiving the recording paper P.
The recording paper P, which has been conveyed through the curved path portion 34c and has a curl, is located on the side of the direction in which it moves along the curl when it is sent out from the outlet portion 34b. The point O at which the feed roller 38 and the pinch roller 39 come into contact with each other is located below the receiving surface 35 in the outlet portion 34a because the recording paper P is conveyed through the conveying path 34 and When the recording paper P is sent out from the portion 34a, the recording paper P comes into contact with the outer peripheral surface of the feed roller 38 before coming into contact with the outer peripheral surface of the pinch roller 39, and is surely moved to the contact portion between the feed roller 38 and the pinch roller 39. is there. The distance S between the point O where the feed roller 38 and the pinch roller 39 come into contact with each other and the surface 35 of the conveyance path 34 which receives the outlet 34b is at least as large as the thickness of the recording paper P. is there. Preferably, a distance S between a point O at which the feed roller 38 and the pinch roller 39 come into contact with each other and a surface 35 of the conveyance path 34 receiving the outlet 34b is
It is not less than the thickness of the recording paper P and not more than the radius of the feed roller 38. This is a range in which the recording paper P can contact the outer peripheral surface of the feed roller 38 and move to the contact portion between the feed roller 38 and the pinch roller 39.
Specifically, the size is about 1.5 mm. In order to provide a step between the point O where the feed roller 38 and the pinch roller 39 come into contact with each other and the receiving surface 35 of the recording paper P at the outlet 34b of the conveying path 34, a conventional receiver at the outlet is required. A method of changing the height of the surface 35 or attaching a film to the receiving surface 35 in the conventional outlet portion may be mentioned, but a method of changing the height of the receiving surface 35 in the outlet portion 34b in consideration of assemblability. Is desirable. The feed roller 38 is rotated by a rotation driving device (not shown), and the pinch roller 39 is rotated by the rotation of the feed roller 38. In the drawing, reference numeral 42 denotes a fixing device provided on the base frame 24; 43, a discharge roller; 44, an exposure device provided on the upper body 23; A document reading device that reads information. The operation of the thus configured recording paper transport device will be described. The recording paper P stacked on the paper cassette 29 is sequentially fed out by the rotating paper feed roller 31, and
Then, the entrance portion 34 is rotated by the rotating transport rollers 36 and 37.
a to the transport path 34. The recording paper P is transported through the transport path 34 and sent to the outlet 34b. The recording paper P is received by the receiving surface 35 at the outlet 34b and sent out of the outlet 34b. Further, the recording paper P
Is transported to the process unit 32 through a portion between the rotating feed roller 38 and the contact portion of the pinch roller 39, and a toner image is formed in the process unit 32.
The recording paper P on which the toner image is formed is fixed to the fixing device 42.
The toner image is fixed at
Is discharged to the outside of the apparatus main body 1. By the way, when the recording paper P is sent out from the outlet 34b of the transport path 34, it does not move in the horizontal direction but moves in the downward direction. In this case, the recording paper P moves in a downward direction due to its own weight or the like. Here, the point O where the feed roller 38 and the pinch roller 39 come into contact with each other is located below the receiving surface 35 at the outlet 34b of the transport path 34. For this reason, as shown in FIG. 2B, even when the recording paper P moves in the downward direction due to its own weight or the like and is sent out from the outlet of the conveyance path, the recording paper P contacts the outer peripheral surface of the pinch roller 39. Before this, it comes into contact with the outer peripheral surface of the feed roller 38. Since the feed roller 38 is rotating by obtaining its own rotational driving force, the recording paper P that has hit the outer peripheral surface is reliably moved to the contact point O between the feed roller 38 and the pinch roller 39, and The sheet can be conveyed through a contact portion with the pinch roller 39. Accordingly, the recording paper P which is fed out of the cassette 29 and conveyed through the conveyance path 34 and sent out in a curled state stops at the feed roller 38 and the pinch roller 39 because of the curled state. Paper jam can be prevented. Further, the recording paper P fed out from the paper cassette 29 is forcedly curved in the process of being conveyed to the outlet 34b through the conveyance passage 34, so that the recording paper P has a curl of curving downward and wrapping around. Therefore, when the recording paper P having the curl is sent out from the outlet portion 34b of the transport path 34, the recording paper P may not move in the horizontal direction but move along the winding direction of the curl and may be sent out. In this embodiment, since the winding direction of the curl is downward, the recording paper P moves in the downward direction and is sent out. Here, the point O where the feed roller 38 and the pinch roller 39 come into contact with each other is located on the side of the winding direction of the curl of the recording paper P with respect to the receiving surface 35 at the outlet 34b of the transport path 34. And away. In this embodiment, since the winding direction of the curl of the recording paper P is downward,
The point O at which the feed roller 38 and the pinch roller 39 come into contact with each other is located below and away from the receiving surface 35 at the outlet 34b of the transport path 34. Therefore, even if the recording paper P is moved out of the outlet 34b of the conveyance path 34 in the winding direction due to the curl as shown in FIG. Before contacting the surface, it comes into contact with the outer peripheral surface of the feed roller 38. Since the feed roller 38 is rotating by obtaining its own rotational driving force, the recording paper P that has hit the outer peripheral surface is reliably moved to the contact point O between the feed roller 38 and the pinch roller 39, and It can be conveyed through a contact portion with the pinch roller 39. Accordingly, the recording paper P fed out of the cassette 29 and conveyed through the conveyance path 34 and sent out in a curled state stops at the feed roller 38 and the pinch roller 39 because of the curled state. Paper jam can be prevented. The present invention is not limited to the embodiments described above, but can be implemented in various modifications. In this embodiment, the winding direction of the recording paper P from the exit portion 34b of the transport path 34 due to the curl is downward. However, the present invention is not limited to this, and the case where the winding direction due to the curl is upward, for example, can be applied. Further, the present invention is not limited to a facsimile apparatus which conveys recording paper, but can be applied to a case where a document is conveyed. As described above, according to the paper transport apparatus of the first aspect of the present invention, the point where the feed roller and the pinch roller come into contact with each other is such that the point where the paper is received at the outlet of the paper transport path On the other hand, it is located on the side of the direction in which the paper with the curl moves along the curl when it is sent out from the exit. For this reason, even if the paper that has been conveyed through the curved conveyance path and has a curl is moved in the direction of winding of the curl from the outlet of the conveyance path and is sent out, the paper remains on the outer peripheral surface of the pinch roller. Before contact, it contacts the outer peripheral surface of the feed roller. Since the feed roller is rotating with its own rotational driving force, the paper abutting on the outer peripheral surface is surely moved to the contact point between the feed roller and the pinch roller, and the contact portion between the feed roller and the pinch roller is contacted. Can be transported through. Therefore, it is possible to prevent the paper fed from the cassette, conveyed through the conveyance path and sent out, from stopping at the feed roller and the pinch roller and causing a paper jam.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a schematic configuration of a facsimile apparatus equipped with a recording paper transport device according to an embodiment of the present invention. FIG. 2A is an enlarged view showing a recording paper transport device in the facsimile apparatus of the embodiment. FIG. 2B is an enlarged view showing a feed roller and a pinch roller in the recording paper transport device. FIG. 3 is an exploded perspective view showing a recording paper transport device in the facsimile apparatus of the embodiment. FIG. 4 is a diagram showing a schematic configuration of a facsimile apparatus equipped with a recording paper transport device as an example of the related art. FIG. 5A is an enlarged view showing a recording paper transport device in the conventional facsimile apparatus. FIG. 2B is an enlarged view showing a feed roller and a pinch roller in the recording paper transport device. [Description of References] 21: Main body of device, 22: Lower main body, 23: Upper main body, 2
9: paper cassette, 31: paper feed roller, 32: process unit, 34: transport path, 34a: entrance, 34b
Outlet, 35 ... Receiving surface, 36 ... Conveying roller, 37 ... Conveying roller, 38 ... Feed roller, 39 ... Pinch roller
O: contact point, P: recording paper.

Claims (1)

(57) [Claim 1] A paper cassette on which sheets of cut paper are stacked, a paper feed roller for feeding out the sheets stacked on the paper cassette, and a sheet fed from the paper cassette A conveying passage having a curved passage portion through which the paper is conveyed and an outlet portion for receiving and sending out the paper conveyed through the passage portion, and provided at a front side of the outlet portion of the conveyance passage and rotated by obtaining rotational driving force. A feed roller and a pinch roller that is pressed against and is rotated by the rotation of the feed roller when pressed in contact with the feed roller and that conveys the sheet fed from the outlet together with the feed roller, the feed roller and the pinch roller The point at which the sheet comes in contact with the sheet at the outlet of the conveyance path and conveys the curved path of the conveyance path The point where the sheet with the curl is given along the curl when the sheet is sent out from the outlet is located at a point where the feed roller and the pinch roller are in contact with each other. Wherein the distance between the sheet and the surface receiving the sheet is at least as large as the thickness of the sheet.