JP2001163471A - Sheet member conveying device and image forming device having it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of the prior art that in opening an ADF with a placing table or a discharge table loaded with documents, the documents slip from the placing table or the discharge table to drop on the back of an image forming device, that is, on the inmost side seen from the operating direction. SOLUTION: This sheet member conveyor device provided on the upper side of an image forming device for conveying a sheet member is provided with a placing table disposed on the image forming device main body to be freely opened and closed for placing a sheet member, a transport mechanism disposed on the image forming device main body to be feely opened and closed for conveying a sheet member placed on the placing table, and a paper feed roller disposed on the conveying mechanism for feeding paper from the placing table. The sheet member transport device for conveying a sheet member is further provided with a drop preventing mechanism which retreats not to obstruct conveyance of a sheet member when the placing table is closed, and prevents a sheet member from dropping in the transport direction to the paper feeding roller with the opening operation of the placing table when the placing table is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device, and more particularly, to a sheet conveying device such as an automatic document conveying device installed above an image forming apparatus. More specifically, in a device in which a mounting table for mounting a sheet member such as a document is formed to be openable and closable, when the mounting table is opened,
The present invention relates to a fall prevention mechanism for preventing a document or the like from falling from a mounting table.

2. Description of the Related Art Conventionally, an image forming apparatus such as a facsimile or a copying machine has been provided in which an automatic document feeder (sheet member feeder) is disposed above an image forming apparatus main body. FIG. 7 shows an example of this type of image forming apparatus. The apparatus shown in FIG. 7 is provided with an automatic document feeder (hereinafter, referred to as an ADF device) at an upper portion of a main body 600.
The ADF device includes a document table 610 and a transport mechanism 620 provided on the right side of the table 610 in the drawing.
In addition, the main body 600 includes a scanner 630 disposed below the mounting table 610, an optical unit 640 disposed below the scanner 630, and an image forming unit 650 disposed below the optical unit 640. I have. Image forming unit 65
0 has a photosensitive drum 651 and a photosensitive drum 6
Reference numeral 51 denotes an image of a document exposed by a laser beam output from the optical unit 640, which is visualized as a toner image and transferred to a transfer sheet. The main body 600 further includes a transfer sheet feeding unit 660 having a sheet cassette 661 disposed below the image forming unit 650, a fixing unit 670 disposed downstream of the transfer sheet feeding unit 660, and a fixing unit 670. And a transfer paper discharge section 680 arranged on the downstream side. The transport mechanism 620 of the ADF device transports the originals stacked on the mounting table 610 one by one to an image reading unit of the image forming apparatus main body by a paper feeding unit such as a paper feeding roller. The original is returned to the mounting table 10. In recent years, with the spread of personal computers, networking of offices has progressed, and printers have been mainly used in offices. There is a growing demand for space saving in offices and cost reduction of equipment used in offices. As a result, a multifunction (multifunctionalized) printer (image forming apparatus) having both a facsimile function and a copy function Has come to be offered. An ADF device attached to such a multi-function image forming apparatus generally includes a document mounting table and a discharge table for reloading a document discharged from the image reading unit. The mounting table and the discharge table are mounted via a hinge mechanism such that one end side thereof can be freely opened and closed upward with respect to the image forming apparatus main body. Thus, in a case where a thick original such as a book original which is stapled is copied, or when a conveyed original has a paper jam, the operation is performed with the ADF device located at the open position. be able to. With the multifunctionalization of the image forming apparatus as described above, there is a demand for a further space-saving and operable apparatus. Therefore, a transfer table for the transfer paper after image formation is provided in parallel with the mounting table of the ADF device facing the front side of the main body, and in order to reduce the operation force for opening and closing the ADF device, the mounting table and the discharge table There is also provided an apparatus in which a portion provided and a portion provided with a transport mechanism are separated from each other so that only a portion provided with a mounting table and a discharge table can be opened and closed.

However, in the conventional apparatus as described above, when the ADF device is opened while the originals are stacked on the mounting table or the discharge table, the originals are read from the mounting table or the discharge table. Slides down and falls on the back side of the image forming apparatus, that is, on the back side when viewed from the operation direction. When opening the ADF device to prevent the document from falling as described above, it is necessary to check in advance whether the document is placed on the loading table or the output tray. If so, they must be removed once and the ADF device must be opened. Therefore, the operability is poor. When a plurality of originals drop, it is troublesome to sort the originals after picking them up. In order to solve the above problems,
For example, a technique disclosed in Japanese Patent Application Laid-Open No. 5-116804 has been proposed. Here, when the opening operation of the upper half of the image forming apparatus main body is detected, the original pressing means, which is also the original sending means, is pressed against the upper part of the original to prevent the original from dropping. However, in the above-described configuration, a press-contact / separation mechanism for the document pressing means is separately required, and a detection means for detecting opening of the main body is also required. Therefore, the number of parts increases, the mechanism becomes complicated, and cost increases. Would. Further, in the case where the document mounting table and the discharge table are provided integrally as described above, there is also a problem that the weight of the entire ADF apparatus becomes heavy, and a load is imposed on an operator during opening and closing operations. .

A sheet member conveying device according to the present invention is provided on an upper portion of an image forming apparatus main body, and conveys a sheet member. The sheet member conveying device includes a mounting table, a conveying mechanism,
And a fall prevention mechanism. The mounting table is provided to be openable and closable with respect to the image forming apparatus main body, and mounts a sheet member. The transport mechanism transports the sheet member placed on the mounting table. The fall prevention mechanism retreats so as not to hinder the conveyance of the sheet member when the mounting table is closed, and when the mounting table is open, the sheet member falls from the mounting table with the opening operation of the mounting table. To prevent According to this device, since the sheet member on the mounting table is prevented from dropping with the opening operation of the mounting table, the user does not need to remove the sheet member when the mounting table is opened. In this sheet member conveying device, it is preferable that the mounting table can be opened and closed independently of the conveying mechanism. In this sheet member conveyance device, it is preferable that the fall prevention mechanism includes a rotation shaft, a fall prevention member, a biasing member, and a regulating member. The rotating shaft is rotatably supported at the downstream end of the mounting table in the transport direction. The fall prevention member is rotatable with the rotation axis,
A first contactable end of the sheet member placed on the mounting table
A position and a second position that does not abut the end of the sheet member can be taken. The urging member urges the fall prevention member toward the first position. The regulating member positions the fall prevention member at the second position when the mounting table is closed. In this sheet member conveyance device, the fall prevention mechanism may further include a rotating member that can rotate together with the rotation shaft and the fall prevention member,
In this case, the urging member urges the rotation preventing member to urge the fall prevention member to the first position side, and the regulating member is provided on the upper surface of the image forming apparatus main body, and the mounting table is closed. In this state, the contact member is preferably an abutting member that abuts on the rotating member to position the drop prevention member at the second position. In this sheet member conveying device, when the image reading device is provided on the upper portion of the image forming apparatus main body, the contact member is provided at a position other than the image reading device,
It has a contact portion that contacts the rotating member when the mounting table is closed, and an inclined portion that contacts the rotating member as the mounting table opens and closes to smoothly rotate the rotating member. Preferably. In this sheet member transport device, it is preferable that a storage portion for storing the drop prevention member at the second position is formed at the downstream end of the mounting table in the transport direction. In this sheet member conveying apparatus, it is preferable that the conveying mechanism has a supply mechanism and a discharge mechanism. The supply mechanism supplies the sheet member mounted on the mounting table to a position corresponding to the image reading unit of the image forming apparatus main body. The discharge mechanism discharges the sheet member on which the image has been read by the image reading unit onto the mounting table. An image forming apparatus according to the present invention includes an image forming apparatus main body and a document conveying device. The image forming apparatus includes an image reading unit that reads an image of a document, a transfer paper conveyance mechanism that conveys transfer paper, and an image forming unit that forms an image read by the image reading unit on the conveyed transfer paper. Have. The document feeder is provided on an upper portion of the image forming apparatus main body, and includes a mounting table, a transfer mechanism, and a fall prevention mechanism. The mounting table is provided to be openable and closable with respect to the image forming apparatus main body, and mounts an original. The transport mechanism transports the original placed on the mounting table. The fall prevention mechanism retracts the document so that it does not hinder the conveyance of the document when the document table is closed, and prevents the document from dropping from the document table when the document table is opened when the document table is opened. I do. In this image forming apparatus, it is preferable that the mounting table can be opened and closed independently of the transport mechanism. In this image forming apparatus, it is preferable that the fall prevention mechanism includes a rotation shaft, a fall prevention member, a biasing member, and a regulating member. The rotating shaft is rotatably supported at the downstream end of the mounting table in the transport direction. The fall prevention member is rotatable with the rotation shaft, and can have a first position capable of contacting an end of the document placed on the mounting table and a second position not contacting the end of the document. The urging member urges the fall prevention member toward the first position. The regulating member positions the fall prevention member at the second position when the mounting table is closed.

An embodiment of the present invention will be described below with reference to the accompanying drawings. First, FIG. 1 is an overall perspective view of an image forming apparatus having an ADF apparatus as a sheet member conveying apparatus according to an embodiment of the present invention. The image forming apparatus shown here has both a copying function and a facsimile function. It is a multifunction machine. FIG. 2 is a sectional view of the image forming apparatus shown in FIG. In these drawings, the image forming apparatus 1 has a main body 1a and an ADF device 1b disposed above the main body la. The main body 1 a includes an image forming unit 4 including an image reading unit 2, an optical unit 3 and a photosensitive drum 41, and a transfer paper transport mechanism 5. An operation panel 6 is arranged on the near side (the right side in FIG. 2) of the upper outer surface of the main body 1a. A transfer paper discharge section 7 is formed in the upper part of the main body 1a from the near side to the middle part in the depth direction of the main body la. A telephone 8 for transmitting / receiving an image of a document to / from an external facsimile is attached to a side portion of the main body 1a. Since the image forming apparatus 1 normally performs a document copying operation, a facsimile transmission operation, and the like on the side where the operation panel 6 of the main body 1a is disposed, the side on which the operation panel 6 is disposed. Is referred to as a near side, and a side facing the side where the operation panel 6 is provided is referred to as a rear side. Further, a first contact glass 11 is provided on the top of the main body 1a, and a second contact glass 12 is provided on the top of the main body 1a and behind the first contact glass 11. The first contact glass 11 is arranged in the still original reading area. Here, the stationary document reading region is a region where the image of the document is read by scanning a stationary document with a scanner 22 described later that constitutes the image reading unit 2. When a document is placed on the first contact glass 11, the document is detected by the document detection sensor S1 and a detection signal is output. Further, the second contact glass 12 is arranged in the moving document reading area. The moving document reading region is a region where the image of the document is read by moving the document with respect to the stationary scanner 22. The ADF device 1b includes: a document table 13;
And a transport mechanism 14 for transporting the original. Mounting table 1
3 is disposed above the first contact glass 11,
The first contact glass 11 surface is openably and closably covered. The drop prevention mechanism of the present invention is applied to the mounting table 13. The transport mechanism 14 is provided above the second contact glass 12. The mounting table 13 has a concave portion formed on the upper surface side, and the concave portion serves as a discharge unit 17 that receives a document discharged from the transport mechanism 14. The transport mechanism 14 has a document insertion port 1 that opens to the front side.
41, a document discharge port 142, and a document transport unit 143. The document discharge port 142 is opened toward the apparatus in the same manner as the document insertion port 141, is positioned below the document insertion port 141, and is positioned above the discharge unit 17. The document transport unit 143 captures the document inserted into the document insertion port 141 toward the rear side, and then reverses the transport direction at an intermediate position and transports the document to the document output port 142 on the near side. A document placement section 144 is provided in front of the document insertion port 141. The document placement section 144
It is disposed above the mounting table 13, and is integrally attached to a pair of supports 131 that are provided to protrude upward at a position facing the rear side of the mounting table 13 (in the depth direction of the paper). The document feeder 143 includes a forward feed roller 143a and a paper feed roller 143 from the upstream side to the downstream side in the transport direction.
b, the first conveying roller pair 143c (the roller 143c ′,
Roller 143c ''), a second conveying roller pair 143d (roller 143d ', roller 143d''), and a discharge roller pair (third conveying roller pair) 143e (roller 143e',
The rollers 143e '') are sequentially killed. Further, the separating roller 143f is disposed in a state of being urged toward the sheet feeding roller 143b. The first transport roller pair 143c, the second transport roller pair 143d, and the discharge roller pair 143e each include a driving roller and a driven roller.
The forward feed roller 143a, the paper feed roller 143b, the drive roller of the first transport roller pair 143c, the drive roller of the second transport roller pair, and the drive roller of the discharge roller pair 143e respectively drive the document downstream by driving the drive motor M1. Rotate in the direction of transport toward the side. Also, the separating roller 1
43f is provided with a torque limiter,
When only one document passes between the separation roller 43b and the separation roller pair 143f, the torque applied to the separation roller 143f is large. When a plurality of originals are overlapped, the torque applied to the separating roller 143f is small, so that the torque limiter acts and the document cannot be rotated. As a result, the original and the separation roller 143
Since the frictional force between the originals is smaller than the frictional force with f, only the uppermost original is transported downstream by the feed roller 143b. Document feeder 143 includes paper feed roller 14
The original detection sensors S2 and S3 are located at a position near the upstream side of the first conveying roller 3b and a position near the downstream side of the second conveying roller pair 143d, respectively.
Are arranged. As a result, when the document stacked with the image forming surface facing upward is placed on the document placing portion 144 and pushed to a position near the upstream side of the sheet feeding roller 143b,
The document detection sensor S2 detects the presence of the document, and the drive motor M1 is driven according to the instruction signal given thereafter, and the documents are conveyed one by one to the downstream side. When the leading end position of the conveyed document reaches a position near the downstream side of the second conveying roller pair 143d, the document detecting sensor S3 detects that, and based on this detection signal, the leading end position of the document is changed to the second contact glass. A scanner 22 to be described later when the
Is controlled so that the reading of the image is started. Thereafter, control is performed so that the image reading by the scanner 22 ends when the rear end position of the document has passed through the second contact glass 12. The document whose image has been read is conveyed to the document discharge port 142 by the discharge roller pair 143e. The document placed on the document placing section 144 is sequentially transported to the downstream side while the document detection sensor S2 is at 0N. The upper and lower surfaces are inverted when the document passes through the second pair of conveying rollers 143 d, and when the original reaches the position of the second contact glass 12, the image forming surface faces the second contact glass 12. Images can be read. Also, the document discharge port 14
The document conveyed to the document 2 is discharged to the discharge unit 17 and is stacked on top with the image forming surface facing downward. As a result,
When the originals are collected from the discharge unit 17, the originals are stacked in the same order as the original. The mounting table 1
As shown in FIG. 3, a pair of arms 13 extend rearward at opposing positions on the rear side (in the depth direction of the paper).
Two. On the other hand, as shown in FIGS. 1 and 2, an upstream guide 145 having a shaft 145a projecting in the lateral direction is formed on the main body 1a side.
2 is rotatably supported by a shaft 145 a of the upstream guide 145. As a result, when the front side of the mounting table 13 is lifted, as shown by the dashed line in FIG.
Together with the first contact glass 1
1 is placed in an open state. When the force for lifting the mounting table 13 upward is released, the mounting table 13 is lowered by its own weight with the shaft 145a as a fulcrum, and is in a state of covering the original mounting surface of the first contact glass 11. As shown in FIGS. 1 and 2, the image reading means 2 includes a guide rail 21 disposed along the side of the first and second contact glasses 11 and 12, and a front side along the guide rail 21. And a scanner 22 disposed so as to be able to reciprocate between the scanner and the rear side. The scanner 22 includes a light source 221 composed of an LED or the like that irradiates an image surface of a document, and a CCD.
And the like, and a mirror 223 for guiding the document image to the reading unit 222. The reading unit 222 normally stands by at a home position which is an intermediate position between the first contact glass 11 and the second contact glass 12. ing. here,
When a document is placed on the first contact glass 11,
The presence of a document is detected by the document detection sensor S1, and the drive motor M2 is driven in response to an instruction signal given thereafter, whereby the scanner 22 temporarily moves from the home position to the leading end position of the document on the operation panel 6 side. .
Then, the light source 221 is turned on and the scanner 22 is turned on.
Moves from the front side, which is the leading end of the document, to the rear side,
The image surface of the document is scanned, and the image is read line by line. The read image data is subjected to predetermined data processing, converted into a digital signal, and stored in a memory (not shown). When the reading of the original image is completed, the light source 22
1 is turned off, and the scanner 22 returns to the home position. When a document is placed on the document placement section 144,
The original is detected by the original detection sensor S2, and the drive motor M2 is driven in accordance with an instruction signal given thereafter,
Thereby, the scanner 22 is moved from the home position to the position of the second contact glass 12. Then, when the document is transported by the transport mechanism 14 and passes over the second contact glass 12, the scanner 22 reads the document image line by line. The read image data is stored in a memory (not shown) in the same manner as described above. In addition,
The light source 221 is turned on before reading an image on a document, and is turned off after reading. When all the originals placed on the original placing section 144 have been conveyed, the scanner 22 returns to the home position. Thus, the second
At the position of the contact glass 12, the scanner 22 reads the original image in a stationary state, so that the movement time of the scanner 22 as in the case of the first contact glass 11 can be reduced, and the reading amount of the image per unit time can be increased. Becomes possible. The optical unit 3 is disposed below the transfer paper discharge unit 7 and has a scanner 22 read from a memory.
The original image read in step S1 or the image transmitted from an external facsimile read from the memory is exposed on the photosensitive drum 41. The optical unit 3 includes a light-emitting unit 31 that converts a weighted signal generated based on image data into a laser beam and outputs the laser beam;
And a reflection mirror 32 that reflects the laser light from the light source toward the photosensitive drum 41. Also, the optical unit 3
Are mounted in the housing 33 and integrally formed with the housing 33.
3 is disposed in the main body 1a in a state where it is fixed to the main body frame in the main body 1a by means such as screws. The image forming unit 4 includes a charger 42 on the upper side along the peripheral surface of the photosensitive drum 41, a developing unit 43 and a charger 42 on the near side of the charger 42.
The cleaning unit 44 is arranged on the rear side of the cleaning unit 44. The photoreceptor drum 41 is rotated in the direction of the arrow by the driving of the drive motor M3, and a charged area is formed on the peripheral surface at a position facing the charger 42. An electrostatic latent image is formed in this electrostatic area by laser light output from the optical unit 3, and the electrostatic latent image is developed into a toner image at a position facing the developing unit 43. A transfer roller 4 is provided below the photosensitive drum 41.
The toner image on the photosensitive drum 41 is transferred to a transfer sheet at a position facing the transfer roller 45.
Further, the toner remaining on the peripheral surface of the photosensitive drum 41 is removed at a position facing the cleaning unit 44 on the downstream side in the rotation direction. Each constituent member of the image forming section 4 is mounted in a housing 46 and is integrally formed with the housing 46. The housing 46 is detachably mounted on a main body frame (not shown) in the main body 1a. A cover 48 is provided on the front side of the image forming unit 4 of the main body 1a.
It can be opened and closed to the near side with 81 as a fulcrum. Thereby, the cover 48 is opened, and the image forming section 4 is moved to the main body la.
It can be taken out from the outside. The transfer paper transport mechanism 5 is formed below the main body 1a, and has a paper feed cassette loading section 52, a paper feed section 53, and a transfer paper transport path 54. The transfer paper transport mechanism 5 includes a pair of registration rollers 55 disposed along the transfer paper transport path 54,
The fixing unit 56 includes a fixing unit 56, a conveying roller pair 57, and a discharge roller pair 58. The paper feed cassette loading section 52 is loaded with a paper feed cassette 51 in which transfer papers P are stacked and stored.
The paper supply unit 53 includes a paper supply roller 531, and the transfer paper P in the paper supply cassette 51 loaded in the paper supply cassette loading unit 52 is sent out from the near side by the paper supply roller 531. The transfer paper transport path 54 is for guiding the transfer paper drawn from the paper supply cassette 51 to the transfer paper discharge unit 7 via the photosensitive drum 41. The paper feed cassette 51 includes a transfer paper mounting table 512 whose rear lower side is a pivot point and whose front side is urged upward by a spring 511, and a paper feed roller 531.
A guide 513 for guiding the transfer paper extracted by the above to the transfer paper transport path 54 is provided inside. The sheet cassette 51 is inserted into the sheet cassette loading section 5 from the front side of the main body 1a.
It is designed to be slid to 2 and mounted. Also,
The paper feed cassette 51 can be pulled out of the main body 1a by pulling it toward the front when replenishing transfer paper or when a jam occurs near the paper feed roller 531. Note that the guide 513 is formed in a curved shape in which the transfer paper mounting table 512 side is concave in order to guide the transfer paper to the upper transfer paper transport path 54. Further, a plurality of ribs 513a are provided at predetermined intervals along the transport direction on the contact surface side of the guide 513 with the transfer paper, so that the transfer paper can be smoothly transported. The paper supply unit 53 has a separation means such as a separation claw or a separation roller (not shown) for preventing double transfer of the transfer sheet, in addition to the sheet supply roller 531. The paper feed roller 531 is disposed above the paper feed cassette 52 and at a position closer to the front. The paper feed roller 531 rotates in the direction of the arrow by driving the drive motor M3 via a clutch (not shown). Conveys transfer paper.
The transfer paper transport path 54 reverses the transfer paper drawn out to the near side of the paper feed cassette 51 to the rear side, and
First pre-transfer guide 5 fed between the transfer roller 45 and the transfer roller 45
41, a second pre-transfer guide 542, a post-transfer guide 543 for feeding the transfer paper on which the image has been transferred by the photosensitive drum 41 to the rear fixing unit 56, and a transfer paper passing through the fixing unit 56 in the transport direction. Turn over the transfer paper discharge section 7 on the near side
Reversing guide 544 and second reversing guide 5 discharged to
45 is provided. Each guide 541, 542, 543,
Numerals 544 and 545 are made of resin or the like, and a plurality of ribs are arranged side by side at predetermined intervals along the transport direction on the contact surface side with the transfer paper, so that the transfer paper can be smoothly transported. ing. The registration roller pair 55 is disposed between the first pre-transfer guide 541 and the second pre-transfer guide 542, and is driven by the drive motor M3 via a clutch (not shown). Optical unit 3
The transfer paper is fed between the photosensitive drum 41 and the transfer roller 45 in synchronization with the formation of the electrostatic latent image on the photosensitive drum 41 by. Then, when one sheet of transfer paper has been fed,
The clutch is released and the drive is stopped. A transfer paper sensor S4 is provided immediately before the pair of registration rollers 55. When the leading end of the transfer paper is detected, the driving of the paper feed roller 531 is stopped after a predetermined time. The fixing unit 56 includes a heat roller 561 located above and a pressure roller 562 located below, and is disposed between the post-transfer guide 543 and the first reversing guide 544. The heat roller 561 has a heater inside, and a pressure roller 562 is pressed against the heat roller 561 with a predetermined spring pressure. Then, while the toner image is fixed on the transfer paper conveyed between both rollers, the transfer paper on which the toner image is fixed is conveyed to the first reversing guide 544 side.
In addition, the transport roller pair 57 includes the first reversal guide 544 and the second
The discharge roller pair 58 is disposed between the reversing guide 545 and the discharge roller pair 58.
Is located at the end position of the second reversing guide 545.
A transfer paper sensor S5 is provided at a substantially intermediate position in the transport direction of the second reversing guide 545 so as to detect transfer paper transport abnormality. The operation panel 6 includes a start switch 61, a mode selection key 62 for selecting a copy mode and a facsimile transmission mode, and an enlargement / reduction key 6.
3, a numeric keypad 64, a function key 65 provided so that a user can arbitrarily set various functions, and a display section 66 capable of visually recognizing the function set by the user are provided. The operation of the image forming apparatus configured as described above will be described below. First, a copy mode or a facsimile transmission mode is selected by the mode selection key 62 of the operation panel 6 and when a document is placed on the document placing portion 144, that is detected by the document detection sensor. When the start switch 61 of the operation panel 6 is turned on, the document is transferred to the transport mechanism 1.
4 transports onto the second contact glass 12.
At this time, the image of the original is read by the scanner 22 moved from the home position to the position of the second contact glass 12, and the read original image is stored in the memory. The document whose image has been read is discharged to the discharge unit 17. When the original to be copied or transmitted by facsimile is bound like a book or the like, the original is placed directly on the first contact glass 11. Then, the document is detected by the document detection sensor S1, and the start switch 61 is turned on, whereby the image surface of the document is scanned by the scanner 22 and the image is read. The read image is stored in the memory. Also, when an image is sent from an external facsimile through a telephone line,
When that signal is detected, it is automatically set to receive mode,
The received image data is stored in the memory. In the facsimile transmission mode, the image data stored in the memory is read and transmitted to the other party's facsimile through the telephone line. In the copy mode or the facsimile reception mode, the image stored in the memory is transferred to a transfer sheet and discharged to the transfer sheet discharge unit 7. That is, in the copy mode or the facsimile reception mode, the charger 42
, The photosensitive drum 41 is charged, a laser beam corresponding to the image data stored in the memory is emitted, and the photosensitive drum 41 is exposed to form an electrostatic latent image. Next, the toner supplied from the developing unit 43 to the photosensitive drum 41 adheres to the electrostatic latent image to form a toner image. On the other hand, the transfer paper stored in the paper feed cassette 51 is fed by the paper feed roller 531 to the pair of registration rollers 55 via the first pre-transfer guide 541. The transfer paper is conveyed to the gap between the photosensitive drum 41 and the transfer roller 45 via the second pre-transfer guide 542 by the registration roller pair 55 in synchronization with the formation of the electrostatic latent image. Next, the toner image on the photosensitive drum 41 is transferred to the transfer paper by the transfer roller 45 to which a voltage having a polarity opposite to the polarity of the electrostatic latent image is applied, and then the transfer paper is separated from the photosensitive drum 41. Then, the sheet is conveyed to the fixing unit 56 via the post-transfer guide 543. The fixing section 56 fixes the toner image on the transfer paper. Further, the transfer paper on which the toner image is fixed is discharged to the transfer paper discharge unit 7 via the first reversing guide 544 and the second reversing guide 545 by the conveying roller pair 57 and the discharging roller pair 58. Next, an example of a specific configuration of the fall prevention mechanism will be described. FIGS. 3, 4, and 5 show specific examples of the fall prevention mechanism, and FIGS. 4A to 4E show the movement of the fall prevention mechanism with the opening operation of the ADF device over time. . The fall prevention mechanism is a rotating shaft 1
33, a pair of contact members (rotating members) 135 fixed to both ends of the rotating shaft 133, and a spring 134 (see FIG. 5) for urging each contact member 135 in the direction of arrow B (see FIG. 5). (Urging means) and a fall prevention member 137. Rotary axis 1
The reference numeral 33 penetrates the mounting table 13 and is rotatably supported. The contact member 135 contacts at least one contact member 136 provided on the frame portion on the upper surface of the image forming apparatus main body shown in FIGS. As shown in FIG. 4, the contacted member 135 includes a contact member 136.
Is formed in a loose arc shape at the bottom in contact with
When the F device 1b is turned from the horizontal position to the upper open position, the F device 1b turns from the state shown in FIG. 4E to the state shown in FIG. More specifically, the contact member 136 includes a flat portion whose upper surface is parallel to the upper surface of the image forming apparatus main body, and an inclined portion which is gently inclined downward. When the ADF device 1b is closed on the upper surface of the device main body la, the contact member 13
6 and the abutted portion 135 of the fall prevention mechanism and the fall prevention member 1
37 has a positional relationship as shown in FIG. 4e. At this time,
The fall prevention member 137 is located in a concave storage portion 201 provided on the mounting table 13 so as not to hinder the conveyance of the document, and is provided at the end of the connection side with the mounting table 13 with the conveying mechanism 14 ( Preferably, it is configured to be accommodated in FIGS. Therefore, the fall prevention member 137 is
When the document is at the horizontal position for transporting the document, the document is hidden by the lower roller 14X, and the document is discharged by the rollers 14Z and 14X. When the mounting table 13 starts to rotate upward, the contacted member 135 gradually comes into contact with the inclined portion on the upper surface of the contacting member 136 in the direction of arrow B shown in FIG. It rotates smoothly in the state. This contacted member 135
The rotation of the rotation shaft 133 rotates in the direction of arrow B, and the rotation of the rotation shaft 133 also rotates the drop prevention member 137 coaxially fixed in the direction of arrow B. Then, the fall prevention member 137 rotates from the state of being stored in the storage portion 201 to an operation position where it acts on the document, and protrudes. As shown in FIG. 3, the mounting table 13
Is provided at the lower end side of the original when it is located at the open position, that is, a refracting portion that abuts and supports the upstream end side in the transport direction. Therefore, when the mounting table 13 is opened, it is possible to prevent the document from dropping from the end of the mounting table 13 due to the bent portion. Next, in the state where the mounting table 13 is closed from the open position to the horizontal position, the contacted member 135 and the fall prevention member 137 are changed from the state illustrated in FIG. It turns sequentially toward the state. That is,
The contact member 135 is provided on the upper surface of the contact member 136 on the apparatus main body side.
Are in contact with each other, and rotate against the urging force of the spring 134. As described above, since the contact member 136 is provided with a gentle slope on the upper surface thereof, the arc portion shelled at the lower part of the contact member 135 is smoothly rotated along the slope. To go. Then, as the contacted member 135 rotates, the rotating shaft 133 to which the contacted member is fixed also rotates. As a result, the fall prevention member 137 rotates and is stored in the storage portion 201, and the fall prevention member 137 does not hinder the document discharge. Although the contact member in this embodiment has a shape including a flat portion and an inclined portion, the shape of the contact member is not particularly limited to this. The shape may be a gentle arc or a semicircle, as long as the rotation of the contacted member is performed smoothly and appropriately. Further, the contact member may also serve as a position regulating member for maintaining a gap for appropriately transporting the document between the upper surface of the apparatus main body 1a and the ADF apparatus 1b. A rotation shaft provided with a fall prevention member is also provided on the document placement section 144 side so as to be linked to the rotation operation of the fall prevention mechanism on the placement table 13 side, and image reading is performed in accordance with the rotation operation of the placement table. The configuration may be such that the previous document can be prevented from falling. In the present invention, the transfer paper discharge unit 7 for discharging the transfer paper is provided in the image forming apparatus main body as an embodiment. However, a transfer paper transport path that can be transported toward the upper part of the apparatus is separately provided. The ADF device is not currently used and the mounting table 1
When the detection sensor detects that no document is loaded on both the document tray 3 and the document placing portion 144, the transfer paper can be discharged onto the placing table 13 or the document placing portion 144 by the user's selection. In this case, it is easy and convenient to take out the transfer paper and visually check the state.

As described above, according to the present invention, a fall prevention mechanism which can reliably prevent the sheet member from falling with a simpler structure is provided. An improved and highly reliable device can be provided at low cost. In addition, since the opening and closing mechanism that can open and close only the sheet mounting table is provided, the burden on the user during opening and closing can be reduced, and the life of the opening and closing mechanism itself can be extended.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of an image forming apparatus having a fall prevention mechanism according to an embodiment of the present invention and a sheet conveying device to which the mechanism is applied.

FIG. 2 is an internal configuration diagram of an image forming apparatus having the sheet conveying device shown in FIG.

FIG. 3 is a side view showing an opening / closing operation of a sheet mounting table in the sheet conveying apparatus shown in FIG.

FIG. 4 is an operation diagram of a fall prevention member according to the present invention.

FIG. 5 is a perspective view of a main part showing a configuration of a fall prevention mechanism according to the present invention.

FIG. 6 is a side view for illustrating a rotation operation of the fall prevention mechanism according to the present invention.

FIG. 7 illustrates an image forming apparatus provided with a sheet conveying device according to the related art of the present invention.

[Explanation of symbols]

 1a: Image forming apparatus main body lb: ADF device 13: Placement table 14: Transport mechanism 144: Document placement section 17: Document discharge section 131: Support body 133: Rotating shaft 134: Spring 135: Contact member 136: Contact Member 137: Fall prevention member 200: Document 201: Concave storage section

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/00 108 H04N 1/00 108Q 1/04 1/12 Z

Claims (4)

[Claims] 1. A sheet member conveying device provided at an upper portion of an image forming apparatus main body and conveying a sheet member, wherein the mounting table is provided to be openable and closable with respect to the image forming apparatus main body, and mounts a sheet member; A transport mechanism that is provided to be openable and closable with respect to the image forming apparatus main body and transports a sheet member placed on the mounting table; and a paper feed roller that feeds paper from the mounting table to the transport mechanism. Further, when the mounting table is closed, the sheet member is retracted so as not to hinder the conveyance of the sheet member, and when the mounting table is opened, the sheet member is moved along with the opening operation of the mounting table,
A sheet member conveying device for conveying a sheet member having the drop prevention mechanism for preventing the sheet member from dropping in the conveying direction to the sheet feeding roller. 2. A sheet member transporting device provided on an upper portion of an image forming apparatus main body and transporting a sheet member, the mounting table being provided openably and closably with respect to the image forming apparatus main body and mounting a sheet member, A transport mechanism that is provided to be openable and closable with respect to the image forming apparatus main body and transports a sheet member placed on the mounting table; and retracts so as not to hinder the transport of the sheet member when the mounting table is closed. In the state where the mounting table is opened, the sheet member transports the sheet member having a drop prevention mechanism for preventing the sheet member from falling in the transport direction with the opening operation of the mounting table. In the member conveying device, the fall prevention mechanism may include a rotation shaft rotatably supported at a downstream end of the mounting table in the conveyance direction, the rotation shaft being rotatable together with the rotation shaft, and integral with the rotation shaft. A fall prevention member that can be configured to have a first position capable of contacting an end of the sheet member placed on the mounting table and a second position not contacting the end of the sheet member. An urging member for urging the fall prevention member toward the first position side; a biasing member rotatable with the rotation shaft and integrally formed with the rotation shaft; A rotating member rotatable together with a member, provided on an upper surface of the image forming apparatus main body, and in a state where the mounting table is closed, abuts on the rotating member and positions the drop prevention member at the second position. A sheet member conveying device, wherein the contact member to be urged and the urging member urge the drop prevention member to the first position side by urging the rotating member. 3. An image reading device is provided at an upper portion of the image forming apparatus main body, and the contact member is provided at a position other than the image reading device, and the mounting table is closed. A contact portion that contacts the rotating member, and an inclined portion that contacts the rotating member with the opening and closing operation of the mounting table to smooth the rotating operation of the rotating member. Claims 1 and 2
4. The sheet member transport device according to claim 1. 4. An image forming apparatus comprising the sheet member conveying device according to claim 1.