JPH058888A - Document feeding device for image forming device - Google Patents

Abstract

PURPOSE:To perform smooth separation of a platen cover from a platen and movement thereof even when a drive means is of a small type, in a device of a type wherein a conveying means and the platen cover are located in juxtaposition and the platen cover is caused to approach and part from the platen. CONSTITUTION:A document feeding device for an image forming device comprises a conveying means 10 to convey a document to a platen P, a platen cover 20 located adjacently to the conveying means 10 in a manner to cover the platen P therewith, a drive means coupled to the platen 20 and separating the one end side of the platen cover 20 around support part serving as a fulcrum and causing the other end side to approach the platen P, and a weight part located on the opposite side to the coupling part of the drive means and assisting movement of the one end side of the platen cover 20 in a direction, in which the platen P is separated, around a support part serving as a fulcrum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document feeder used in an image forming apparatus such as a copying machine.

[0002]

2. Description of the Related Art Conventionally, there is known an apparatus in which a conveyor belt is provided to cover the entire surface of a platen of an image forming apparatus, and an original is conveyed and set on the platen by driving the conveyor belt.
However, in this known device, the length of the conveyor belt is set in correspondence with the maximum length of the original document. 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 apparatus, it is necessary to convey a frequently used short document from one end to the other end of a long conveyor belt. Therefore, there is a problem in that it takes a long time to set the document conveyance set.

An apparatus which solves this problem and shortens the transport set time of a frequently used short original document is disclosed in Japanese Unexamined Patent Publication (Kokai) No.
It is disclosed in Japanese Patent No. 13532. This apparatus has a first supporting means provided on one end side of the image forming apparatus for stacking a document, and a document provided on approximately one half of the platen and fed from the first supporting means to the platen. A short conveying belt to be set, a platen cover provided on the platen adjacent to the conveying belt, and a document discharged from the same side as the document introducing side of the conveying belt, which is provided above the conveying belt. A second supporting means.

In this apparatus, when the original is shorter than the conveyor belt, the original is introduced from one end of the conveyor belt from the first supporting means, the original is conveyed and set on the platen by the conveyor belt, and the other end of the post-exposure conveyor belt is set. Documents are being ejected from.

[0005]

However, the apparatus described in this publication has a problem that in the case of a long original, the original must be set on the platen by lifting the conveyor belt and the platen cover.

Therefore, an apparatus has been proposed (non-disclosure) which solves this problem and can automatically feed a long original. In this apparatus, a transport means such as a transport belt is provided on approximately half of the platen. Then, in the case of a long original, the original is carried in from one end of the conveying means, the conveying means subsequently conveys the original, the leading edge of the original is brought out of the other end of the conveying means, and the rear edge of the original is introduced onto the platen After that, the conveying means is driven in reverse to feed the original backward, and a part of the original is inserted into the gap between the platen and the platen cover and set.

In this apparatus, it is necessary to separate the platen cover from the platen so that the document can be easily inserted into the space between the platen cover and the platen when the document is reversely fed and set and discharged after being exposed. On the other hand, at the time of exposure, it is necessary to bring the platen cover close to the platen side.

Therefore, the platen cover is engaged with the support portion and the driving means is connected to the platen cover so that one end side of the platen cover is separated from the platen and the other end side is brought close to the platen with the support portion as a fulcrum. It is proposed to do so (private).

In this case, however, the driving means may become large due to the weight of the platen cover and the friction of the supporting portion.

It is an object of the present invention to provide an apparatus in which one side of the platen cover is separated from the platen by the drive means with the support portion as a fulcrum and the other end side is brought close to the platen, and the platen cover is smoothly moved up even with a small drive means. An object of the present invention is to provide a document feeding device for an image forming apparatus that can be moved and that is low in cost and small in size.

[0011]

In order to achieve the above object, the present invention engages a platen cover with a support portion and connects driving means to the platen cover to connect one end side of the platen cover with the support portion as a fulcrum. The platen is separated from the platen, and the other end side can be freely approached to the platen. The platen cover is provided on the opposite side to the connecting part between the platen cover and the driving means, and the one end side of the platen cover moves in the platen separating direction with the supporting part as a fulcrum. A weight section is provided.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention can be applied to a copying machine, various printers, facsimiles, etc. As an example, a document feeding apparatus applied to a 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 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 covers a certain area corresponding to approximately half of the platen P. The transport unit 10, the platen cover unit 20 that also covers the remaining area of the platen P, and the document set on the document tray unit 30 that is provided above the platen cover unit 20 are separately fed toward the platen P. Separation and feeding unit 40, paper discharge unit 50 that receives the exposed document transported by transport unit 10 and discharges it from platen P, and storage unit 6 that stores the document discharged by this paper discharge unit 50.
0, a hinge unit 70 that supports the document feeder F so as to be openable and closable above the platen P of the copying machine M, and a drive unit.
And a control unit 80.

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 document D at the reference point X, a copy corresponding to the document can be obtained.

The reading section T is the maximum size that can be copied, and is indicated by a chain line in the figure. For example, the A3 size (297 mm x 420 mm) is the maximum size that can be copied, the A3 size is a large size, and the A4 size (210 mm x 29 mm).
7mm) is assumed to be a small size. Therefore, the entire length of the reading section T (between X and Z) is for large-sized documents, and half (X-
(Between Y) is for small size originals. In FIG. 20, the small-sized document D is positioned in the reading unit T in accordance with the reference point.

In FIG. 2, two drive motors M1 and M2 provided in the document feeder F and sensors S1 to S for collecting information necessary to control the operation of the document feeder F.
5 and control board 89 are shown.

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

The drive motor M2 is drivingly connected to the carrying section 10 and is driven and controlled mainly based on output signals from the sensors S2, S3 and 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 originals separated by the separating / feeding unit 40 to the platen P, and is a resist for detecting the leading edge or the trailing edge of the originals passing through the conveying path. It is a sensor.

The sensor S3 is a switchback sensor for detecting the leading edge or trailing edge of the document conveyed in the paper discharge section 50.

The sensor S4 is an output shaft 8 of the drive motor M2.
6 is a photo sensor that detects the amount of rotation of an interrupter 871 (described later) provided in FIG.

The sensor S5 is provided on the hinge portion 70, and the original document feeding device F with respect to the copying machine M has a platen P.
It is detected whether the upper state of the platen P is open or the upper side of the platen P is closed as shown in FIG.

Further, the accommodating portion 60 is provided with a projecting member 62 extending in a direction substantially parallel to the document conveying direction. The projecting member 62 is for leaning a document stored in the storage section 60, and when the stored document is longer than the storage section 60, the tip thereof protrudes from the storage section 60, and the tip of the projecting document is protruded. Is to prevent the document 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
Is an original tray unit 30 as a first supporting unit for loading originals from an upstream side (right side in FIG. 3) to a downstream side (left side in FIG. 3) and an original on the tray is separated into one sheet. There are provided a separate feeding unit 40 that conveys the original document and a document conveying unit 10 as a conveying unit that receives the original document conveyed by the separate feeding unit 40 and further conveys it to the downstream side.

A platen cover section 20 is provided below the separating and feeding section 40 on the platen P side, and an original received from the original conveying section 10 is provided on the front and back sides above the original conveying section 10. Paper ejection unit 5 that conveys paper while reversing it
0 is provided. Above the separating / feeding unit 40 and the document transporting unit 10, a storage unit 60 for storing the document transported by the paper discharge unit 50 is provided.

In the document feeder F, the document tray section 3
Reference numeral 0 denotes a loading tray 31, and a pair of side edge guides 32L for regulating the side edges of a document set on the loading tray 31.
32R and auxiliary tray 33.

The side edge guides 32L and 32R are arranged along the guide guide 321 in the width direction of the document (vertical direction in FIG. 4).
Move to. 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 at the reference line K shown in FIG.

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

In the separating / feeding unit 40, the image to be processed into one separated original is guided downward from a predetermined position of the platen P (in this example, the center Y point of the reading unit T) onto the platen P. A document transport path R1 is formed, and this document transport path R1
Is partitioned by guide plates 410 and 411. Then, along the document conveying path R1, a separating unit is arranged for separating the documents set on the tray 31 and feeding them one by one. That is, the pickup roller 42 is provided at the entrance side of the transport path R1 so as to be able to move forward and backward with respect to the mounting tray 31, and the paper feed roller 43 and the separation belt 44 enter the transport path R1 from the respective guide plates 410 and 411 so that they do not contact 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 substantially at the center (point Y) of the reading section T defined on the upper surface of the platen P.

At the entrance of the conveying path R1, the presence or absence of a document on the loading tray 31 in cooperation with the document stopper 46 provided so as to be movable back and forth with respect to the guide plate 411 and the sensor S1 (see FIG. 2). A lever 47 is provided to detect the error, and a sensor S2 is provided between the paper feed roller 43 and the registration roller 451 on the conveyance path R1. The document stopper 46, the pickup roller 42, the paper feed roller 43, and the separation belt 44 provided along the transport path R1 are shown in FIGS.
As shown in 0, the power from the motor M1 is rotated in a predetermined direction via the belt drive transmission means 810, 811 and the plurality of gears G.
It is configured to rotate.

Assuming that one original is pulled out from the placing tray 31 and sent to the conveyance path R1, the motor M
1 rotation (normal rotation) is transmitted to the shaft 831 via the gears G2, G3, G4, and 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 abuts on a stopper (not shown), the spring clutch 834 prevents the shaft 833 of the document stopper 46 from being driven with a certain driving force or more.

The pickup roller 42 has a shaft 82 for holding the paper feed roller 43 by means of a swing arm member 821.
Since the lever 836 is pivotally supported on the shaft 831 so that the lever 836 is fixed to the shaft 831 and comes into contact with the swing arm member 821, the swing arm member 821 is rotated downward toward the document to scan the document. Contact the surface. When the pickup roller 42 comes into contact with the original, the contact pressure of the pickup roller 42 with respect to the original is kept constant by the spring clutch 834.

Further, the forward rotation of the motor M1 is performed by the gears G1, G5, G
It is transmitted to the shafts 82 and 84 via 6, G7, and the paper feeding roller 43
And the separation belt 44 are rotated in 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 paper feed roller 43 advances the document. It is designed to rotate following it.

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. 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, 43 and the separation belt 44, but the document stopper 46 and the lever Drive is transmitted to 836, and the motor M1 is rotationally driven in a direction opposite to that when the motor M1 is normally rotated.

Further, the shaft 838 is provided with a spring clutch 837, and when the motor M1 reversely rotates, the document stopper 4 is inserted.
6 and the lever 836 are prevented from being driven upward by a force greater than a predetermined value.

With the structure of the separating and feeding section 40 described above,
When the motor M1 rotates in the normal direction, only the pickup roller 42 and the paper feed roller 43 rotate in the forward direction (original conveying direction),
The separation belt 44 rotates in the reverse feeding direction. As a result, the documents placed on the loading 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
Is rotated to separate the pickup roller 42 from the surface of the original.

The document conveying section 10 comprises an endless belt-shaped conveying belt 13, a pair of pulleys 11 and 12 for driving the conveying belt 13 so as to be able to rotate forward and backward, and a plurality of press rollers 14 for pressing the conveying belt 13 against the platen P. Become. Further, the document transport unit 10 has approximately half (X) of the maximum copy document size (reading unit T) on the upper surface of the platen P on the reading reference point X side.
(Between Y and Y)).

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 this document transport unit 10, the document discharged from the exit of the transport path R1 is transported to the reference point X of the reading unit T, or is transported in front of the reference point X and is discharged. Can be transported in the opposite direction.

As shown in FIGS. 3 and 7, the original feeding section 10
Behind the exit (reference point X) of the above, a paper discharge unit 50 is provided in series with the document conveying unit 10. The paper discharge unit 50 is
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 be able to rotate forward and backward, and a rolling roller 5 that transmits the drive of the conveyor belt 13 to the pulley 53.
4 and the document discharged from the exit of the document path R2 in the storage section 60
Has guide members 55 and 56 for guiding to
A discharge path R3 is formed between 5 and 56 to guide the original sent from the conveyor belt 13 while reversing the original.

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

The transfer roller 54 is biased directly by a spring member (not shown) on the surface of the conveyor belt 13 at a position facing the driven pulley 12, and the fourth and seventh rollers are also provided.
As shown in the figure, they are in contact with each other at substantially the center of the conveyor belt 13.

Further, the discharge belt 51 and the pair of pulleys 5
2, 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, which facilitates assembly.

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 disposed above the loading tray 31, the copying machine F is in a state where the document D to be separated and fed and the copied document D1 overlap each other as shown in FIG.
It is placed and stored above the platen of. In other words, it is possible to configure a document conveying device which is small and lightweight, is not particularly limited in the size of the document to be conveyed, and can easily handle the processed document.

Referring to FIGS. 3, 8 and 9, the platen cover portion 20 is provided below the platen P side of the separating / feeding portion 40, and is provided in parallel with the platen P, and the platen cover 21 and the platen cover 21. Support members 22 and 23 that support the cover 21 at a predetermined distance from the platen P and are detachably attached to the document feeder F, and the platen cover 21.
And an elevating means 24 (driving means) for bringing the platen P close to and away from the platen P.

The platen cover 21 has an engagement fixing portion for engaging and fixing the platen cover 21 to the support member 22.
211, a slide portion 212 (engagement portion) that engages with the support member 23 (support portion) and slides the platen cover 21 in a direction substantially parallel to the platen P, the support member 22,
23 can be gripped by an operator in order to release the engagement / fixation between the platen cover 21 and the platen cover 21, and is provided downstream of the support member 23 in the sliding direction of the platen cover 21 and has a relatively large U-shape. Shaped weight part 213
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.

In FIG. 9, the platen cover 21 is attached to the support member 2
2 and 23 are removed. Although the drawing shows the document feeder F closing (covering) the platen P of the copying machine M, the platen cover 21 is normally removed by the document feeder F above the platen P. The separation belt 44 and other mechanisms provided in the separation feeding unit 40 can be easily maintained.

The platen cover portion 20 is a region on the upper surface of the platen P other than the area covered by the document conveying portion 10, that is, approximately half (between Y and Z) on the opposite side of the reading reference point X of the reading portion T. It has a size to cover.

With reference to FIGS. 6, 7 and 11, the document conveying section 1
0, the drive system of the platen cover unit 20 and the separate feeding unit 40
A part of the drive system 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 photosensor for generating a pulse in response to light passing through the slit of the rotating interrupter 871. A pulse generator 87 composed of S2 is provided.

The conveyor belt 13 forming the document path R2 receives the power from the motor M2 as belt drive transmission means 850, 851 and the shaft 8
The drive side pulley 11 is rotated via the gears 52 and the gears G8, G9, G10 so that the drive side pulley 11 is driven in the forward direction (original conveying direction) and the backward feeding direction.

Further, the driven pulley 12 of the conveyor belt 13
The transfer roller 54 provided above the
Drive is transmitted directly from the surface of the sheet, and the discharge belt 51 is driven at the same peripheral speed as the conveying belt 13 in the same document conveying direction.

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

That is, the registration roller 451, the driving pulley 11, and the paper discharge belt 51 are one driving source (motor M2).
And the registration roller 451 rotates at a substantially equal peripheral speed so that the registration roller 451 can convey the original document path R2 and the paper ejection path R3 at the same speed as the original document sent through the conveyance path R1. That is,
The originals conveyed in the passages R1, R2, R3 are
It is designed to move at a constant speed. The rotary drive system described above can be controlled based on the clock signal of the pulse generating means 87. On the other hand, the drive of the shaft 852 is driven by the gears G11 and G.
It is transmitted to the drive shaft 242 via 12, G13. The drive shaft 242 is
A gear is connected so as to rotate in the same direction as the pulley 11 that drives the conveyor belt 13, and the platen cover 21 is slid in the same direction as the forward and reverse conveying directions of the conveyor belt 13. 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. Torque limiter 8 built into shaft 852
By 53, the platen cover 21 is held at the position shown by the solid line in FIG. 8 with a constant force.

When the conveyor 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. At this time, the weight portion 213 acts to help move the platen cover 21 in the direction away from the platen P about the support member 23 of the platen cover 21.

Hinge portion 70 shown in FIGS.
Is composed of a hinge 71 with a spring that supports the document feeder F on the upper surface of the copying machine M so as to be openable and closable, and a hinge 72 without a spring.

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 conveying device F side, a pin 713 connecting both portions 711 and 712, and both portions 7.
Spring means 7 for urging 11,712 in the opening direction around the pin 713
It is composed of 14 and.

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 (horizontal direction in FIG. 4). This hinge position corresponds to the positions of the motors M1 and M2 and the motors M1 and M.
The position of the center of gravity shifted from the position of the rotary drive system or the like connected to 2 to the upstream side in the transport direction of the apparatus F is approximately corresponded.

The springless hinge 72 comprises 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 transport device F in the document transport direction, and includes a support member 721 fixed to the copying machine M and a concave support portion 722 of the frame cover of the document transport device F. It is rotatably connected by a pin 723.

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

FIGS. 12 and 13 (A) to 13 (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 presence of the document D is confirmed by the empty sensor S1. , The document stopper 46 is the guide plate 41.
1, the pickup roller 42 rotates and descends to come into contact with the document 31 on the loading tray 31. As a result, the document D is sent forward and the paper feed roller 43
The document D is moved forward by the sheet feeding roller 43 which is inserted between the separation belt 44 and the separation belt 44 and rotates in the conveying direction. At this time,
When a plurality of documents D are placed on the loading tray 31 as shown in FIG. 12B and a plurality of documents are simultaneously sent out by the pickup roller 42, the separation belt 44 is rotated in the reverse feeding direction by the separation belt 44. The lower document, which contacts 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 comes into contact with the stopped registration roller 451 and pinch roller 452 after the leading edge thereof is detected by the registration sensor S2. Document D
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, the document D is bent to some extent, and the leading edge is evenly distributed between the registration roller 451 and the pinch roller 452.
It is pressed against the tangent part of. As a result, the registration roller 451 and the pinch roller that start rotating after the document D comes into contact
The tip is drawn in parallel with the 452 and sent out forward. (Skew Correction Function) The document D transported on the transport 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 way is driven by the transport belt 13 in synchronization with the registration rollers 451.
The document path R2 is sent forward by.

At this time, the length of the document D in the transport direction can be determined by counting the pulse signals from the pulse generating means 87 from the time when the motor M2 is activated until the trailing edge of the transported document passes the registration sensor S2. .. That is, at least the registration rollers 45 involved in the conveyance of the document D.
Since the conveyor belt 13 is synchronized with the pulse of the pulse generating means 87 and maintains the same conveyor speed, the motor M2
It is possible to previously recognize the number of pulses from the start of the process until the reading reference point X is reached, and the registration sensor S2 detects the rear end of the document D when the leading edge of the document D is on the way from the point Y to the point X. Then, it can be seen that the conveyed document is at least the length between the points X and Y. That is, in this case, it is determined that the document has a small size. (Refer to FIG. 16) As shown in FIG. 17, when the original has a small size, the pulse generating means 8 is started after the rotation of the motor M2 is started.
After 7 has counted a predetermined pulse (A pulse), the conveyor belt 13 is stopped. 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, and if the presence of the original D 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 feed the next document D from the loading tray 31 toward the registration rollers 451 and the copying machine M is operated to make a copy. Run. (Fig. 13
(Refer to (A)) When the copying is completed, the conveyor belt 13 is stopped after the pulse generation means 87 has counted a predetermined number of pulses (A pulse) from the start of the motor M2. At this time, the first (first) original document is stored in the storage tray 6 with the rear end thereof being restrained by the paper discharge unit 50.
No. 1 is discharged on the tip side. (See FIG. 13 (B)) When the empty sensor S1 detects the document D to be copied on the mounting tray 31, the above-described operation is appropriately repeated,
As shown in FIG. 13C, the copied documents D are sequentially stacked on the storage tray 61.

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

Start of conveyance of the above-mentioned document (FIG. 12 (A))
Subsequently, the document D is moved forward along the document path R2 between the conveying 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 judged to be large. .. In this case, the trailing edge of the original is the registration sensor S.
2, the pulse generating means 87 causes the predetermined pulse (B
The document D is continuously conveyed until the number of pulses is counted.

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. There is.

Then, the conveyor belt 13 is rotated in the reverse direction to cause the original D
Are fed back along the upper surface of the platen P. This allows
The document D enters between the platen P and the platen cover 21 between points YZ 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. That is, 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 section T. The conveyor belt 13 is stopped at the point W. (Fig. 1
4 (D)) The conveyance belt 1 is provided until the pulse generation means 87 counts a predetermined pulse (B pulse) after the trailing edge of the document (the trailing edge at the time of forward feeding; the right side in the figure) passes the registration sensor S2.
In consideration of the size of the used document, the switchback sensor S3 is provided in the vicinity of 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 when the document 3 is conveyed. 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 a direction away from the platen P. This makes it easier 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.

Thereafter, the document D is conveyed again by the conveying belt 13 in the forward direction, and the trailing edge of the document D fed in the forward direction is the reading portion T.
When it is located at the reference point X, the conveyor belt 13 is stopped. That is, after the pulse generator 87 counts a predetermined pulse (D pulse) that is 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 conveyance belt 13, the platen cover 21 moves in the direction in which the platen P approaches the platen P. As a result, the point Y-Z of the reading unit T
The document D that has entered between the platen P and the platen cover 21 in between is pressed to the platen P side. Then, copy is executed.

After the copying is completed, when the empty sensor S1 does not detect the original on the tray 31, the conveying belt 13 and the discharge belt 51 are driven in the forward feeding direction to store the original D through the discharge path R3. Send it to the 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 at the time of forward feeding) is conveyed to the substantially central portion (point Y) of the reading unit T by the forward feeding of the discharge belt 13.

Next, the next original is conveyed to the position of the registration roller 451 by the above-mentioned original feeding and separating operation.
(FIG. 15 (C)) Here, the motor M2 is activated to simultaneously rotate the registration roller 451, the conveyance belt 13, and the discharge belt 51.
As a result, the copied document D1 is sent to the storage tray 61, and the subsequent document D2 is transferred to the point Y of the reading unit T.
The document D is fed forward by the transport belt 13 until the trailing edge of the document is located at the point Y of the reading section T, as described above. (FIG. 15D) According to the document feeder F having the above-described configuration, a relatively small size document feeder system having a size smaller than about half (the size between X and Y) of the reading unit T on the platen P and having a large size. The original document (X-Z size) can be effectively conveyed, and the rationalization of the system, the cost reduction of the apparatus, and the reduction in size and weight can be achieved.

In the above embodiment, about twice the small size is set as the large size, but it goes without saying that even if the large size (between X and Z) is made larger than twice the small size (between XY), Alternatively, it can be practically made small.

[0089]

According to the present invention described above, the conveying means for conveying the document to the reading position provided on the platen, the conveying means adjacent to the platen so as to cover the platen, and the supporting portion via the engaging portion. It is provided on the side opposite to the connecting part of the driving means, and the platen cover which is fitted to the platen cover, the drive means which is connected to the platen cover and which has one end side of the platen cover separated from the platen and the other end side close to the platen with the supporting part as a fulcrum. , A weight portion that helps the one end side of the platen cover to move in the platen separating direction with the support portion as a fulcrum.

Therefore, the platen cover can be smoothly moved in the direction away from the platen even with a small driving means, and a low-cost and small-sized document feeder can be realized.

[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 Document transporting device P Platen D Document 10 Document transporting part (transporting device) 20 Platen cover part 21 Platen cover 23 Supporting member 24 Elevating means (driving device) 30 Document tray part 40 Separation feeding part 50 Paper Output Section 60 Storage Section 70 Hinge Section 212 Slide Section (Engaging Section) 213 Weight Section

Claims (1)

Claim: What is claimed is: 1. A conveyance means for conveying a document to a reading position provided on a platen of an image forming apparatus; A platen cover provided with an engaging portion that moves in a separating direction and that engages with a supporting portion that moves the other end side in a direction closer to the platen; and a platen cover connected to the platen cover and using the supporting portion as a fulcrum. A drive unit that separates one end side of the platen cover from the platen and the other end side of the platen close to the platen is provided on the opposite side of the connecting unit of the drive unit, and one end side of the platen cover is provided with the support unit as a fulcrum. An original feeding device for an image forming apparatus, comprising: a weight portion that assists in moving in a separating direction.