JPH053236U - Document feeder for image forming device - Google Patents

Abstract

(57) [Abstract] [Purpose] The transporting means 60 and the platen cover 2 on the opening / closing member F.
In a device in which 0 and 0 are arranged side by side, downsizing is facilitated and maintenance is facilitated. The opening / closing member F is provided with a separating means 40 for separating an original and sending it out, and the separating means 40 is provided for the platen cover 2.
The platen P is covered with 0 from the platen P side, and the platen cover 20 is detachable from the opening / closing member F.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

The present invention relates to a document feeder used in an image forming apparatus such as a copying machine.

[Prior Art]

 2. Description of the Related Art Conventionally, there is known a device in which a conveyor belt covering the entire surface of a platen of an image forming apparatus is provided and an original is conveyed and set on the platen by driving the conveyor belt. However, in this known apparatus, the length of the conveyor belt is set so as to correspond to the original having the maximum length. On the other hand, documents that are actually frequently used (for example, A4 and B5) are often shorter than the documents having the maximum length. However, in the above-mentioned known device, it is necessary to convey a frequently used short document from one end to the other end of a long conveyance belt. Therefore, there is a problem in that it takes a long time to set the document conveyance set.

An apparatus that solves this problem and shortens the transport set time of a frequently used short document is disclosed in Japanese Patent Application Laid-Open No. 2-13532. This apparatus includes a first supporting means projecting from one end side of the image forming apparatus for stacking originals, a separating means for separating the originals on the first supporting means one by one, and sending the separated originals. A short conveying belt which is provided in approximately half and conveys and sets the original sent from the first supporting means on the platen, a platen cover which is adjacent to the conveying belt and covers the platen, and above the conveying belt. Second supporting means is provided for accommodating the document discharged from the side opposite to the document introducing side of the conveying belt. Further, an opening / closing member is connected to and supported by the platen so as to be openable / closable, and the opening / closing member is provided with the first supporting means, the separating means, the conveyor belt, the platen and the second supporting means.

In this apparatus, when the original is shorter than the conveyor belt, the original is carried in from one end of the conveyor belt to be conveyed and set, and is ejected from the other end of the conveyor belt. On the other hand, if the original is longer than the conveyor belt, lift the conveyor belt and platen cover and set the original on the platen.

[0004]

[Problems to be solved by the device]

 However, the apparatus described in the above publication has a problem that the apparatus becomes large in size because the separating means for separating and feeding the originals one by one is provided so as to project outside the platen.

An object of the present invention is to provide a document feeding apparatus for an image forming apparatus, which is downsized and facilitates maintenance in an apparatus in which a conveying means and a platen cover are arranged side by side on an opening / closing member. ..

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention is provided with a supporting means for stacking originals and a separating means provided on the opening / closing member for separating the originals on the supporting means into one sheet and sending the separated originals. The cover covers the platen side, and the platen cover is removable from the opening / closing member.

[0007]

【Example】

 The present invention can be applied to a copying machine, various printers, a facsimile, and the like. As an example, a document feeding device applied to the copying machine will be described with reference to the accompanying drawings.

A document feeder F is placed and mounted above the copying machine M shown in FIG. The document feeder F has a substantially square outer shape so that the document feeder F does not largely project to the left and right sides when viewed from the front of the copying machine M.

A platen P is provided in the upper part of the copying machine M, and the document feeder F placed so as to cover the platen P has a fixed area corresponding to approximately half of the platen P. The transport section 10 for covering, the platen cover section 20 for covering the remaining area of the platen P, and the document set on the document tray section 30 provided above the platen cover section 20 are separated toward the platen P. A separating / feeding unit 40 for sending, a paper discharging unit 50 for receiving the exposed document conveyed by the conveying unit 10 and discharging it from the platen P, and a storage unit 60 for storing the document discharged by the paper discharging unit 50. The document feeder F is provided with a hinge 70 that supports the document feeder F above the platen P of the copying machine M so as to be openable and closable, and a drive / control unit 80. The frame of the document feeder F is an opening / closing member that can be opened / closed with respect to the platen P via a hinge portion 70.

FIG. 20 shows a state in which the document feeder F in FIG. 1 is released above the platen P, and the effective reading range (reading section T: length X-Z) is defined on the upper surface of the transparent platen P. Therefore, one end of the reading unit is determined as the reading reference point X. At the time of copying, by arranging one end of the manuscript D at the reference point X, a copy corresponding to the manuscript can be obtained.

The reading unit T has the maximum size that can be copied, and is indicated by a chain line in the drawing. For example, it is assumed that the A3 size (297 mm × 420 mm) is the maximum size that can be copied, the A3 size is a large size, and the A4 size (210 mm × 297 mm) is a small size. Therefore, the entire length of the reading section T (between X and Z) is for large size originals, and half thereof (between X and Y) is for small size originals. In FIG. 20, the small-sized original document D is positioned in the reading unit T in accordance with the reference point.

FIG. 2 shows two drive motors M1 and M2 provided in the document feeder F, sensors S1 to S5 for collecting information necessary for controlling the operation of the document feeder F, and control. Substrate 89 is shown.

The drive motor M1 is drivingly connected to the separating / feeding unit 40, and is drive-controlled mainly based on output signals from the sensors S1 and S5.

The drive motor M2 is drive-coupled to the transport unit 10 and is drive-controlled mainly based on output signals from the sensors S2, S3, S4.

The sensor S1 is an empty sensor for detecting the presence / absence of a document set on the document tray section 30.

The sensor S2 is provided on the way of the conveying path for conveying the original separated into one sheet by the separating / feeding unit 40 to the platen P, and detects the leading edge or the trailing edge of the original passing through the conveying path. It is a registration sensor.

The sensor S3 is a switchback sensor that detects the leading edge or the trailing edge of a document conveyed in the paper discharge unit 50.

The sensor S4 is a photo sensor that detects the amount of rotation of an interrupter 871 (described later) provided on the output shaft 86 of the drive motor M2.

The sensor S5 is provided on the hinge portion 70, and whether the document feeder F is in an open state with the upper part of the platen P open to the copying machine M, or as shown in FIG. It detects whether it is in the closed state with the upper part blocked.

Further, the accommodating portion 60 is provided with a protruding member 62 extending in a direction substantially parallel to the document conveying direction. The protruding member 62 is provided to allow the original stored in the storage section 60 to sit down. When the original stored in the storage section 60 is longer than the storage section 60, the leading end thereof protrudes from the storage section 60, and the protruding document is This is to prevent the leading edge from hanging above the document tray section 30.

Next, the document feeder F will be described in detail with reference to FIGS.

As shown in FIGS. 3 and 4, the document feeder F has the image to be processed on the lower side from the upstream (right side in FIG. 3) to the downstream (left side) in the document feeding direction. A document tray unit 30 as a supporting unit for stacking documents, a separating / feeding unit 40 as a separating unit that separates and conveys the document on the tray into one sheet, and the separating and feeding unit 40 conveys the document. A document transport unit 10 is provided as a transport unit that receives a document and transports the document further downstream.

A platen cover 20 is provided below the separating / feeding unit 40 on the platen P side, and an original received from the original conveying unit 10 is provided above the original conveying unit 10 on the downstream side. A paper discharge unit 50 is provided that conveys paper while turning it over. Above the separating / feeding unit 40 and the document conveying unit 10, there is provided a storing unit 60 for storing the document conveyed by the paper discharging unit 50.

In the document feeder F, the document tray section 30 includes a loading tray 31, and a pair of side edge guides 32 L and 32 R for regulating the side edges of the document set on the loading tray 31. It consists of an auxiliary tray 33.

The side edge guides 32 L and 32 R move in the width direction of the document (vertical direction in FIG. 4) along the guide guide 321. Further, a rack and pinion mechanism (not shown) is connected to the side edge guides 32L and 32R, and the central portion of the original set on the loading tray 31 is positioned on the reference line K shown in FIG. ..

The auxiliary tray 33 is rotatably attached to the placing tray 31 by a rotation shaft 331, and stably supports the rear end side of a large-sized document placed on the placing tray 31.

The separating / feeding unit 40 is arranged so that the image to be processed on a single separated document is placed on the lower side of the platen P from a predetermined position of the platen P (the center Y point of the reading unit T in this example). A document conveying path R1 is formed as a first guiding means for guiding, and the document conveying path R1 is divided by guide plates 410 and 411. Then, along the document feeding path R1, there is arranged a separating means for separating the documents set on the loading tray 31 and feeding them one by one. That is, the pickup roller 42 is provided at the entrance side of the conveyance path R1 so as to be able to move forward and backward from the mounting tray 31, and the paper feed roller 43 and the separation belt 44 enter the conveyance path R1 from the respective guide plates 410 and 411 so that they are not in contact with each other. They are arranged in a state of being overlapped with each other. Further, a registration roller 451 and a pinch roller 452 are provided facing each other on the exit side of the transport path R1.

The exit portion of the transport path R1 is located at substantially the center (point Y) of the reading unit T defined on the upper surface of the platen P.

At the entrance portion of the transport path R1, the document stopper 46 provided so as to be able to move forward and backward with respect to the guide plate 411, and the sensor S1 (see FIG. 2) cooperate with each other to store the documents on the tray 31. A lever 47 for detecting the presence / absence is provided, and a sensor S2 is provided between the sheet feeding roller 43 and the registration roller 451 on the conveyance path R1. As shown in FIGS. 5 and 10, the document stopper 46, the pickup roller 42, the paper feed roller 43, and the separation belt 44, which are provided along the conveyance path R1, convey the power from the motor M1 to the belt drive transmission means 810, 811 and a plurality of them. It is configured to rotate / rotate in a predetermined direction via the gear G.

Considering here a case where one document is pulled out from the loading tray 31 and sent to the conveyance path R1, the rotation (normal rotation) of the motor M1 is transmitted to the shaft 831 via the gears G2, G3, G4. The rotation of the shaft 831 drives the drive transmission member 832 to rotate the shaft 833 in a predetermined direction.

At this time, since the document stopper 46 moves to the position shown by the chain line in FIG. 3, the document on the loading tray 31 can be separated and fed. When the document stopper 46 rotates (falls) and hits a stopper (not shown), the spring clutch 834 prevents the shaft 833 of the document stopper 46 from being driven with a driving force above a certain level.

Further, since the pickup roller 42 is swingably supported by the swing arm member 821 on the shaft 82 holding the sheet feeding roller 43, it is fixed to the shaft 831 and also swing arm. The rotation of the lever 836 contacting the member 821 causes the swing arm member 821 to rotate downward toward the document and contact the surface of the document. When the pickup roller 42 contacts the original, the contact pressure of the pickup roller 42 on the original is kept constant by the spring clutch 834.

Further, the normal rotation of the motor M1 is transmitted to the shafts 82, 84 via the gears G1, G5, G6, G7, and causes the paper feed roller 43 and the separation belt 44 to rotate in mutually different directions.

A one-way clutch 822 is incorporated in the gear G7, and even if the rotation of the gear G7 is stopped, when the document is forcibly conveyed forward, the feed roller 43 advances the document. It is designed to be driven by and rotate.

Further, the one-way clutch 823 is also incorporated in the gear G6, and even if the rotation of the gear G5 is stopped, when the document is forcibly conveyed forward, the separation belt 44 follows the forward movement of the document. Then it is designed to rotate.

The gear G1 has a built-in one-way clutch 824. When the motor M1 rotates in the reverse direction, the gear G1 idles, and the drive is not transmitted to the rollers 42 and 43 and the separation belt 44. The drive is transmitted to the lever 836, and the motor M1 is rotationally driven in the opposite direction to that when the motor M1 is normally rotated.

Further, the shaft 838 is provided with a spring clutch 837 so that the document stopper 46 and the lever 836 are not driven upward by a predetermined force or more when the motor M1 reversely rotates.

With the configuration of the separating / feeding unit 40 described above, when the motor M1 rotates in the normal direction, only the pick-up roller 42 and the sheet-feeding roller 43 rotate in the forward direction (original conveying direction), and the separating belt 44 moves in the reverse feeding direction. Rotate to. As a result, the documents placed on the placing tray 31 are conveyed one by one from the entrance to the exit of the conveyance path R1.

When the motor M1 rotates in the reverse direction, the lever 836 rotates to separate the pickup roller 42 from the surface of the original.

The document transport unit 10 includes an endless belt-shaped transport belt 13, a pair of pulleys 11 and 12 that drives the transport belt 13 so that it can rotate forward and backward, and a plurality of press rollers 14 that press the transport belt 13 against the platen P. Become. Further, the document conveying section 10 has a size sufficient to cover approximately half (between XY) of the maximum copy document size (reading section T) on the upper surface of the platen P on the side of the reading reference point X. ..

A conveyor belt 13 is provided at the exit of the conveyor path R1. The conveyance belt 13 forms a document path R2 between itself and the platen P, the entrance of the document path R2 is located substantially at the center (point Y) of the reading section T, and the exit is set at the front end of the reading section T. It is located almost at the reference point X.

By the document conveying section 10, the document discharged from the exit of the conveying path R1 is conveyed to the reference point X of the reading section T, or is conveyed in front of the reference point X and is discharged. Can be transported in the opposite direction.

As shown in FIGS. 3 and 7, a paper discharge unit 50 is provided behind the exit (reference point X) of the original document transport unit 10 and is continuous with the original document transport unit 10. The paper discharge unit 50 includes an endless belt-shaped paper discharge belt 51, a pair of pulleys 52 and 53 that drive the paper discharge belt 51 so as to rotate in the forward and reverse directions, and a rolling roller 54 that transmits the drive of the conveyor belt 13 to the pulley 53. And guide members 55 and 56 for guiding the document discharged from the exit of the document path R2 to the storage portion 60, while reversing the document sent from the conveyor belt 13 between the guide members 55 and 56. A discharge path R3 is formed as a second guide means for guiding.

A leaf spring member 57, which is fixed to the guide member 55 at one end and presses the document against the paper discharge belt 51 at the other end, is provided at a position away from the facing portion of the paper discharge belt 51.

The rolling roller 54 is urged directly to the surface of the conveyor belt 13 by a spring member (not shown) at a position facing the driven pulley 12, and as shown in FIGS. Is in contact with the transport belt 13 at approximately the center thereof.

Further, the discharge belt 51, the pair of pulleys 52, 53, and the rolling contact roller 54 are integrally supported by the pair of left and right side plates 58, and can be fixed to the outer cover of the conveyance device F as a unit. Easy to install.

In this embodiment, the document discharged from the document path R2 between the conveyor belt 13 and the platen P is introduced into the paper discharge path R3 and conveyed to the storage section 60.

The storage section 60 is composed of a storage tray 61 as a second supporting means, and a projecting member 62 extending in a direction substantially parallel to the document transport direction. Since the storage tray 61 is arranged above the loading tray 31, as shown in FIG. 16 (D), the copying machine F with the original D to be separated / fed and the copied original D1 overlap each other. It is placed and stored above the platen of. In other words, it is possible to configure a document feeder that is small and lightweight, and that the size of the document to be transported is not particularly limited, and that the processed document can be easily handled.

To describe with reference to FIGS. 3, 8 and 9, the platen cover portion 20 is provided below the separating / feeding portion 40 on the platen P side, and the platen cover 21 parallel to the platen P is provided. Supporting members 22 and 23 that support the platen cover 21 at a predetermined distance from the platen P and are detachably supported by the document feeder F, and elevating means 24 that moves the platen cover 21 close to and away from the platen P. I have it.

The platen cover 21 includes an engagement fixing portion 211 that engages and fixes the platen cover 21 with respect to the support member 22, and a support member 23 that engages the platen cover 21 with respect to the platen P. The slide portion 212 that slides in parallel with each other can be grasped by an operator to release the engagement / fixation between the support members 22 and 23 and the platen cover 21, and the support member 23 allows the platen cover 21 to move. A U-shaped weight portion 213, which is provided downstream in the sliding direction and has a relatively large weight, is provided.

The support member 23 is fixed to the frame of the document feeder F. The support member 22 is connected to the drive shaft 242 by a connecting member 241.

FIG. 9 shows the platen cover 21 removed from the support members 22 and 23. The figure shows a state in which the document feeder F closes (covers) the platen P of the copying machine M. Normally, the platen cover 21 is removed by the document feeder F above the platen P. In this state, the separation belt 44 and other mechanisms provided in the separation feeding unit 40 can be easily maintained.

Further, the platen cover portion 20 is an area on the upper surface of the platen P other than the area covered by the document conveying portion 10, that is, substantially half (Y-Z interval) opposite to the reading reference point X of the reading portion T. ) Has a size to cover.

With reference to FIGS. 6, 7 and 11, the drive system of the document conveying section 10, the platen cover section 20 and a part of the drive system of the separation feeding section 40 will be described.

The output shaft 86 of the motor M2 is provided with an interrupter 871 formed by forming slits on a disk at equal intervals, and a photo that generates a pulse in response to light passing through the slit of the rotating interrupter 871. A pulse generating means 87 composed of the sensor S2 is provided.

The conveyor belt 13 forming the document path R2 is forwarded by rotating the drive side pulley 11 via the belt drive transmission means 850, 851, the shaft 852, and the gears G8, G9, G10 by the power from the motor M2. It is configured to be driven in the direction (document conveying direction) and the backward feeding direction.

Further, the rolling roller 54 provided above the driven pulley 12 of the transport belt 13 is directly driven by the surface of the transport belt 13, and the discharge belt 51 has the same circumference as the transport belt 13. It is driven at the same speed in the same document transport direction.

A registration roller 451 is fixed to the shaft 852, and is driven in the same document conveyance direction at the same peripheral speed as the conveyance belt 13.

That is, the registration roller 451, the driving pulley 11, and the paper discharge belt 51 are rotated by one driving source (motor M2) in cooperation, and at the same speed as the original sent by the registration roller 451 through the conveyance path R1. Rotate while maintaining a substantially equal peripheral speed so that the document path R2 and the paper discharge path R3 can be conveyed. That is, the document conveyed in the passages R1, R2, R3 moves at a constant speed regardless of the forward and reverse directions. The rotary drive system described above can be controlled based on the clock signal of the pulse generation means 87. On the other hand, the drive of the shaft 852 is transmitted to the drive shaft 242 via the gears G11, G12, G13. The drive shaft 242 is gear-connected so as to rotate in the same direction as the pulley 11 that drives the conveyor belt 13, and slides the platen cover 21 in the same direction as the conveyance direction in which the conveyor belt 13 is reversed. When the transport belt 13 is driven in the forward direction (document transport direction), the platen cover 21 is held at the position indicated by the solid line in FIG. The platen cover 21 is held at the position indicated by the solid line in FIG. 8 with a constant force by the torque limiter 853 incorporated in the shaft 852.

When the transport belt 13 is driven in the reverse feeding direction, the platen cover 21 is held at the position indicated by the chain line in FIG. 8, that is, the position separated from the platen P by the reverse rotation of the drive shaft 242. The platen cover 21 is held at the position indicated by the chain line in FIG. 8 with a constant force by the torque limiter 854 incorporated in the shaft 242.

The hinge portion 70 shown in FIGS. 1, 4, 19 and 20 is composed of a spring-equipped hinge 71 that supports the document feeder F on the upper surface of the copying machine M so as to be openable and closable, and a springless hinge 72. There is.

The spring hinge 71 includes a main body fixing portion 711 fixed to the copying machine M side, an attached fixing portion 712 fixed to the transporting apparatus F side, a pin 713 connecting both portions 711, 712, and both portions 711. , 712 and a spring means 714 that biases the 712 in the opening direction around the pin 713.

Further, it is provided at a position slightly upstream (right side in the figure) from the central portion of the apparatus F with respect to the document conveying direction of the document conveying apparatus F (left and right direction in FIG. 4). This hinge position substantially corresponds to the center of gravity position shifted to the upstream side in the transport direction of the apparatus F from the positions of the motors M1 and M2 and the position of the rotary drive system connected to the motors M1 and M2.

The springless hinge 72 includes a support member 721 fixed to the copying machine M side, a concave support portion 722 provided in the document feeder F, and a pin 723 connecting both members 721, 722. The hinge 72 is provided at a position downstream (on the left side in FIG. 4) of the document transporting device F in the document transporting direction, and is provided with a support member 721 fixed to the copying machine M and a concave support portion 722 of the frame cover of the document transporting device F. Are rotatably connected by a pin 723.

The operation of the document feeder F having the above structure will be described below.

FIGS. 12 and 13 (A) to (C) show the case of handling a relatively small size original such as A4 to letter size horizontal.

FIG. 12A shows a state in which the document D is set on the placing tray 31 prior to copying, and when a copy command is given to the copying machine M, the existence of the document D is confirmed by the empty sensor S1. Then, the document stopper 46 retracts below the guide plate 411, and the pick-up roller 42 descends while rotating to come into contact with the placing tray 31 document D. As a result, the document D is sent forward, enters between the paper feed roller 43 and the separation belt 44, and the document D is advanced by the paper feed roller 43 rotating in the transport direction. At this time, when a plurality of originals D are placed on the placing tray 31 as shown in FIG. 12B and a plurality of originals are simultaneously sent out by the pickup roller 42, the separation belt 44 which rotates in the reverse feeding direction. As a result, the lower original that contacts the separation belt 44 is prevented from moving forward. Therefore, only one original is allowed to pass forward by the paper feed roller 43.

In this way, the fed document D contacts the registration roller 451 and the pinch roller 452 in the stopped state after the leading edge of the document is detected by the registration sensor S2. By stopping the rollers 42, 43 and the belt 44 after a lapse of a predetermined time from the detection of the leading edge of the document D, the document D is bent to some extent and the leading end is uniformly pressed against the tangent portion of the registration roller 451 and the pinch roller 452. As a result, the document D is pulled in by the resist roller 451 and the pinch roller 452, which start rotating after coming into contact with each other, in a state in which the leading ends are parallel to each other, and is fed forward. (Skew Correction Function) The document D conveyed through the conveyance path R1 as described above is guided to the entrance of the document path R2 at the substantially center (point Y) of the reading section T of the platen P. The document D that has entered the entrance of the document path R2 formed between the transport belt 13 and the platen P in this manner is sent forward along the document path R2 by the transport belt 13 that is driven in synchronization with the registration rollers 45 1.

At this time, the length of the document D in the conveyance direction is determined by counting the pulse signals generated by the pulse generating means 87 from the time when the motor M2 is activated until the trailing edge of the conveyed document passes the registration sensor S2. I can judge. That is, at least the registration roller 451 and the conveyor belt 13 that are involved in the conveyance of the document D maintain the same conveyance speed in synchronization with the pulse of the pulse generation means 87, and therefore, from the activation of the motor M2 to the reading reference point X 1. The number of pulses can be recognized in advance, and when the registration sensor S2 detects the trailing edge of the document D while the leading edge of the document D is on the way from the point Y to the point X, the transported document is at least between the points XY. It can be seen that it is less than or equal to the length. That is, in this case, it is determined that the original is small size. (Refer to FIG. 16) As shown in FIG. 17, when the original is small in size, after the rotation of the motor M2 is started, the pulse generation means 87 counts a predetermined pulse (A pulse), and then the conveyor belt 13 is started. To stop. As a result, the document D can be stopped at the reading position in which the leading edge of the document is accurately aligned with the reference point X, as shown in FIG.

Next, it is judged whether or not the empty sensor S1 detects the original document, and if the presence of the original document D 1 is not detected, the copying machine M is operated to execute copying. When copying is completed, the conveyance belt 13 and the paper discharge belt 51 are operated to guide the document D to the paper discharge path R3 and discharge it to the storage tray 61.

When the empty sensor S1 detects a document, the motor M1 is activated to send the next document D from the mounting tray 31 toward the registration rollers 451 and the copying machine M is operated to perform copying. Run. (See FIG. 13A.) When copying is completed, the pulse generation means 87 counts a predetermined number of pulses (A pulse) after the motor M2 is activated, and then the conveyor belt 13 is stopped. At this time, the front end of the first (first) document is discharged to the storage tray 61 with the rear end thereof being restrained by the paper discharge unit 50. (Refer to FIG. 13B) When the empty sensor S1 detects the document D to be copied on the placing tray 31, the above-described operation is appropriately repeated, and as shown in FIG. The copied documents D are sequentially accumulated.

FIGS. 14 and 15 (A) to (D) show the case of handling a large-sized document longer than the X-Y interval on the platen P defining a relatively small-sized area.

Subsequent to the start of document transportation (FIG. 12A), the document D is moved forward along the document path R2 between the transportation means 13 and the platen P.

As shown in FIGS. 16 and 18, when the document D advancing along the document path R2 passes the reading reference point X and the trailing edge of the document does not pass the registration sensor S2, the document D is determined to be large. .. In this case, the document D is continuously conveyed after the trailing edge of the document passes the registration sensor S2 until the pulse generating means 87 counts a predetermined pulse (B pulse).

When the trailing edge of the document reaches the entrance (point Y) of the document path R2, the leading edge of the document D passes through the paper discharge section 50 and is conveyed to the upper surface of the storage tray 61, as shown in FIG. 14C. ing. Next, the conveyance belt 13 is rotated in the reverse direction, and the document D is fed backward along the upper surface of the platen P. As a result, the document D enters between the platen P and the platen cover 21 between the points Y and Z of the reading unit T.

The document D is fed backward by the conveyor belt 13 until the leading edge of the document passes the reference point A of the reading section T by a predetermined amount. The backward feeding of the document D is controlled based on the detection signal of the trailing edge of the document (the leading edge during the forward feeding; the left side in the drawing) of the switchback sensor S3. In other words, after the trailing edge of the document to be fed back passes the switchback sensor S3, the conveyance belt 13 is fed backward until the pulse generating means 87 counts a predetermined pulse (C pulse), and the trailing edge of the document is read by the reading unit. The transport belt 13 is stopped at the point W at the point T. (See FIG. 14D.) The conveyance belt 13 is provided until the pulse generating means 87 counts a predetermined pulse (B pulse) after the trailing edge of the document (the trailing edge during forward feeding; the right side in the figure) passes the registration sensor S2. When the document D is conveyed by the switchback sensor S3, the switchback sensor S3 is provided near the downstream side of the platen P in the forward feeding direction so that the leading edge of the document is always detected by the switchback sensor S3. It is arranged.

When the document is fed backward by the conveyor belt 13, the drive system of the platen cover 21 described above is simultaneously driven, and the platen cover 21 moves in the direction away from the platen P. This makes it easy for the document D to enter between the platen P and the platen cover 21 between the points Y and Z of the reading unit T.

After that, the document D is again transported in the forward direction by the transport belt 13, and the transport belt 13 is stopped when the trailing edge of the document D being fed is located at the reference point X of the reading unit T. That is, after the pulse generator 87 counts a predetermined pulse (D pulse) that has overrun from the reference point X in the backward feeding, the feeding of the feeding belt 13 in the forward feeding direction is stopped. (See FIG. 15A.) As described above, when the document D is conveyed by D pulses by the forward rotation of the conveyor belt 13, the platen cover 21 moves in the direction of approaching the platen P. As a result, the document D that has entered between the platen P between the points Y and Z of the reading unit T and the platen cover 21 is pressed to the platen P side. Then, copy is executed.

After the copying is completed, when the document is not detected on the loading tray 31 by the empty sensor S1, the transport belt 13 and the paper discharge belt 51 are driven in the forward feeding direction to move the document D through the paper discharge path R3. And sends it to the storage tray 61.

When the succeeding copy document D is detected by the empty sensor S1, the motor M2 is driven by a predetermined pulse (E pulse) according to the size of the document to be copied, as shown in FIG. 15B. The trailing edge of the document (the trailing edge during forward feeding) is conveyed to the approximate center of the reading unit T (point Y) by the forward feeding of the paper discharge belt 13.

Next, the next document is conveyed to the position of the registration roller 451 by the above-described document separating and feeding operation. (FIG. 15 (C)) Here, the motor M2 is activated to simultaneously rotate the registration roller 451, the conveyor belt 13, and the paper discharge belt 51. As a result, the copied document D1 is sent to the storage tray 61, and the following document D2 advances along the conveyance path R1 toward the point Y of the reading unit T, and as described above, the trailing end of the document is read by the reading unit. The document D is sequentially fed by the transport belt 13 until it is located at the point Y of T. (FIG. 15 (D)) According to the document feeder F having the above-described configuration, a relatively small size document transport system having a size smaller than about half (the size between X and Y) of the reading unit T on the platen P is used. Even large-sized documents (X-Z size) can be effectively transported, and the system can be streamlined, the cost can be reduced, and the size and weight can be reduced.

In the above embodiment, approximately twice the small size is set as the large size, but it goes without saying that the large size (between X and Z) is made larger than twice the small size (between XY). However, it is also possible to make it small or small.

[0083]

[Effect of the device]

 In the invention described above, the separating means is provided on the opening / closing member, the separating means is covered from the platen side by the platen cover, and the platen cover is detachable from the opening / closing member. Therefore, the downsizing of the device can be realized, and the separation means can be easily maintained by removing the platen cover.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment in which a document feeder according to the present invention is applied to a copying machine.

FIG. 2 is a perspective view showing an embodiment showing the internal structure of a part of the same document feeder.

FIG. 3 is a side sectional view of the same document feeder as above.

FIG. 4 is a plan view of the same document feeder as above.

FIG. 5 is a plan view showing a drive system of a part of the separation supply unit.

FIG. 6 is a plan view showing a drive system of a part or all of a separation / feed unit, a document conveyance unit, and a platen cover unit.

FIG. 7 is a perspective view illustrating a main configuration of a paper discharge unit.

FIG. 8 is a side view schematically illustrating a platen cover unit.

FIG. 9 is a side view illustrating an outline of attachment / detachment of a platen cover.

FIG. 10 is a side view showing a drive system of a part of the separation supply unit.

FIG. 11 is a side view showing a drive system of part or all of a separation / feed unit, a document conveyance unit, and a platen cover unit.

FIG. 12 is an explanatory diagram showing a feeding state of a small-sized document.

FIG. 13 is an explanatory diagram showing a feeding state of a small-sized document.

FIG. 14 is an explanatory diagram showing a feeding state of a large-sized document.

FIG. 15 is an explanatory diagram showing a feeding state of a large-sized document.

FIG. 16 is a flow chart for explaining the separating / conveying operation of the document conveying device.

FIG. 17 is a flowchart for explaining the operation of conveying and discharging a small-sized document.

FIG. 18 is a flowchart for explaining the operation of conveying and discharging a large-sized document.

FIG. 19 is a side view illustrating the outline of a hinge portion.

FIG. 20 is a perspective view showing an embodiment in which a document feeder according to the present invention is applied to a copying machine with a platen released.

[Explanation of symbols]

 M Copying machine (image forming apparatus) F Original document conveying device P Platen D Original document 10 Original document conveying section (conveying means) 20 Platen cover section 30 Original document tray section (supporting section) 40 Separation feeding section (separating section) 50 Paper ejection section 60 Storage 70 Hinge

Claims (1)

Claims for utility model registration: Claims: 1. A platen of an image forming apparatus is provided with an openable / closable opening / closing member, and the opening / closing member covers the conveying means for conveying and setting an original on the platen and the original on the platen. An original feeding device for an image forming apparatus, in which a platen cover is provided side by side, is provided with supporting means for loading originals, and separating means provided on the opening / closing member for separating and feeding the originals on the supporting means into one sheet, An image forming apparatus, wherein the separating means is covered from the platen side by the platen cover, and the platen cover is detachable from the opening / closing member.