JPH0262337A - Automatic copy feeding device - Google Patents

Abstract

PURPOSE:To prevent the generation of the frictional sound between the contactglass and a carrier roller during document ejection by forming a moving means to have the document carrier roller moved from a copy putting plate for the separation based on the detection by a detector means. CONSTITUTION:In having a document S ejected on the upper part of a document keeping means by an ejection roller 30, passing through a nip position corre sponding to rollers composed of the ejection roller 30 and a document carrier roller 22, an end point of the document S turns a microswitch 42 on. Based on the on signal, a solenoid 56 is excited, and a swing plate 54 is swung anti- clockwise. The sheet carrier roller 22 is separated from the upper part of the contactglass 6 by the swing operation. As a result, racing of the carrier roller 22 at the contactglass 6 in the last stage of ejecting operation is completely prevented, and having the generation of the frictional sound between these 6 and 22 suppressed, biased abrasion of the carrier roller 22 is thus eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic document feeder of a type that conveys and ejects documents by appropriately contacting the document placement plate and rotating the document forward and backward.

(Prior Art) In recent years, image forming apparatuses such as electrostatic copying machines have been equipped with automatic document feeders (
Vehicles equipped with ADF (ADF) are becoming popular. As this automatic document feeder, for example, Japanese Patent Laid-Open No. 60-11855
An example is the one disclosed in Publication No. 1.

This automatic document conveying device is provided with a paper feeding means for feeding a document placed on a document supply table, and the document fed by the paper feeding means is conveyed to a predetermined position on a contact glass. After being subjected to scanning exposure, the conveyed original is fed or ejected to, for example, an ejected original placing portion formed on the upper surface of the automatic document conveying device.

However, this conveyance means is constituted by an endless conveyance belt attached to the contact glass surface portion of the document conveyance device body, and the structure of the document conveyance device body is generally complicated, resulting in high manufacturing costs. On the other hand, due to the complexity of the mechanism, such automatic document conveying devices have the problem of increasing the size of the device, making it difficult to apply them to small-sized copying machines and the like.

Therefore, in order to solve these problems, the present applicant previously proposed a device that does not employ a belt-like conveyance mechanism. That is,
An automatic document transport system that uses the forward and reverse rotation of a transport roller that is in contact with the contact glass to transport the original on the contact glass from the document supply table to the contact glass, and from the contact glass to the ejected document tray. It is a device (Japanese Patent Application No. 63-61333).

(Problems to be Solved by the Invention) Although the automatic document feeder previously proposed by the present applicant has been greatly improved in terms of simplification of the mechanism and reduction in cost, there are still problems to be solved. Remaining. For example, there are the following problems. That is, the document conveyed onto the contact glass is conveyed along the discharge path from the rear end side by the reverse rotation of the conveyance roller that is performed subsequent to the end of the scanning exposure. Mechanically, the rotation of the discharge roller installed near the exit of the discharge path is
Continue rotating until the leading edge of the document is completely ejected. Therefore, the conveyance roller that rotates together with the discharge roller also continues to rotate. However, since this conveyance roller has the function of conveying the original to a predetermined position on the contact glass, a structure is adopted in which it comes into contact with the contact glass. Therefore, in such an original ejecting operation, even though there is no longer any original between the contact glass and the original, the rotation continues slightly (idling state), and as a result, the contact glass and the conveyance roller are separated for a short time. A rubbing sound will be generated.

Therefore, the main object of the present invention is to solve the above-mentioned problems. Another object of the present invention is to solve the above-mentioned problems with a simple mechanism.

(Structure of the Invention) In order to achieve the above-mentioned object, the present invention employs the following characteristic structure.

a document supply unit equipped with a paper feeding mechanism that feeds the document on the document feed table upwardly on the document placement plate; a document storage section that stores the document on which an image has been formed on its upper surface; a document holding device comprising a document covering sheet member that covers the back side; a document conveying roller configured to be rotatable in forward and reverse directions and conveying the document fed from the document supplying device to a predetermined position on the document placement plate; , an ejection path for guiding the original transported by the original transport roller to the original document storage section; an ejection roller provided in the ejection path; a detection means for detecting;
a document conveying/discharging means comprising a moving means for moving the document conveying roller away from the document placing plate based on detection by the detecting means; a driving means for driving the document supplying means and the document conveying/discharging means; and It has a structural feature in that it has the following.

(Function) The present invention has the following effects by employing the above-described configuration.

When the original is moved along the ejection path to be ejected to the original storage area due to the reverse rotation of the original transport roller, the end of the original (in this case, if the feeding direction side from the original platen is considered as the leading edge), (the rear end) reaches the nip position of the discharge roller.

In this embodiment, the ejection roller is configured to eject the original in pair with the original transport roller or another driven roller. Therefore, when these roller pairs reach a state where the document can be ejected, sufficient conveying force is transmitted to the document only by the rotation of these roller pairs, so it is especially important for contact glass-like document parts. No driving force is required to be transmitted from the document transport roller. Therefore, the detection means is the ejection roller.

When it is detected that the edge of the document has passed through the contact glass position, it issues a detection signal to that effect, and based on this detection signal, the moving means moves the document conveyance roller away from the contact glass. moves the document transport roller.

As a result, the document transport roller and the contact glass maintain a non-contact state, and the document is ejected by the roller pair consisting of the document transport roller and the ejection roller. Although not present, it is possible to completely prevent the conveying roller from idling on the contact glass in state B) in which the document is still held between the roller pair.

(Example) The present invention will be described below using an example in which a copying machine is used as an image forming apparatus. In this embodiment, the case where the ejection roller works together with a moving document transport roller to form a roller pair, or the case where it works together with a roller pair with a driven roller separate from the moving document transport roller will be explained. . However, the present invention is not limited to this example, but is within the scope of the present invention as long as the basic technical idea is the same.

Referring to FIGS. 2 and 3, a copying machine 2 is provided with an optical system, an image processing section, and a paper conveying section inside a housing 4, as is known per se. A document placement plate (hereinafter sometimes referred to as contact glass) 6 is provided at the top of the housing 4 for placing a document thereon. Also,
A paper feed cassette 8 for supplying paper and a paper discharge tray 10 for receiving copied paper are provided on the right and left sides of the housing 4 in the figure, respectively.

The automatic document feeder 1 according to the present invention has a housing 4 that can be freely opened and closed between a closed position (Fig. 3) that covers the contact glass 6 of the copy m2 and an open position (Fig. 2) that releases the contact glass 6. It is removably provided on the top surface of the holder using a well-known hinge mechanism 12.

One giant group ■Direct transportation mainstay! The automatic document feeder 1 in this specific example includes (1) a second
As shown in FIGS. 3, 3, and 6, document supply means A (second (Fig.); (ii) a document holding means B having a document storage section 18 on its upper surface for storing the document for which copying has been completed;
3) and (mountain) the internal space of the document holding means B, located on the side of the document supplying means A, which holds the document S sent from the paper feed mechanism 16 to a predetermined position on the contact glass 6. After completing the copying operation of the transported original S, the original transporting and ejecting means C (second Figure) and (1
v) A driving means D (FIG. 6) for driving the original supplying means A and the original transporting and discharging means C.

A major feature of the present invention is the document conveying and discharging means C.
The main feature is that a document transport roller 22 (described later), which is a component of the document S, is configured to be movable in relation to ejection of the document S.

The automatic document feeder l in this specific example will be described in detail below in the order of document supply means A, document holding means B, document conveyance/ejection means C, and drive means.

(Original Supply Means A) (Original Supply Table 14 and Paper Feeding Mechanism 16) Referring to FIG. 4 and FIG. This document supply table 14 is arranged in an inclined state with the contact glass 6 side lowered, and below near the lower end there is a hole for checking whether the document S has been placed on the document supply table 14. A detector 181 is arranged.This detector 181 connects the tip of the detection arm 1B2 to the document supply table 1.
4 is exposed on the surface, and is rotated downward by the weight of the placed document S to detect the presence or absence of the document. A document restraining member 185 is attached to the lower end of the document supply table 14 to prevent the placed document S from moving forward until it is time to feed the document S. This document restraining member 185 is made of a disconnected circuit-shaped member that is rotatable about a shaft 186, and normally has a tension spring 1 at its tip.
It is in a state of protruding upward from the document supply table 14 due to the urging force of 87, and when the document S is fed, a solenoid 188 is activated to rotate the tip downwardly of the document supply table 14 and allow the document S to advance. .

The paper feed mechanism 16 includes a delivery roller mechanism 210 that initially feeds the originals S on the original supply table 14 one by one, and a delivery roller mechanism 210 that feeds the originals in the direction of the contact glass 6 and prevents double feeding of the originals S. It is composed of a paper feed roller mechanism 220.

The feed roller mechanism 210 has a base end connected to the paper feed roller mechanism 22.
A pair of support arms 211 that are rotatably mounted on the rotation shaft 221 of the example 0 and whose tips extend toward the upstream side of the document supply table 14.
A shaft 212 is rotatably attached to the tip of the support arm 211, and the shafts 212 are arranged at appropriate intervals in the axial direction of the shaft 212.

The separation roller mechanism 220 has a shaft 221 and a shaft 222 which are vertically spaced apart from each other so as to sandwich the sheet surface of the document S on the downstream side of the restraining member 185, and a shaft 222 that is arranged at an appropriate distance in the axial direction of the shaft 221. It is composed of a plurality of paper feed rollers 223 arranged at intervals, and a plurality of separation rollers 224 arranged at appropriate intervals in the axial direction of the shaft 222 and alternately arranged with the paper feed rollers 223. A substantially crescent-shaped notch 223a is formed in a portion of the outer peripheral surface of the paper feed roller 223. This notch 223a is located on the separation roller 224 side except when the document S is being fed, and is located on the separation roller 224 side.
Even if a document S is interposed between the separation roller 23 and the separation roller 224, it does not interfere with conveyance of the document by the document conveyance roller 22, which will be described later.

The separation roller 224 is rotated in synchronization with the paper feed roller 223 when the paper feed roller 223 feeds the document S, and also rotates in the opposite direction to the feeding direction of the document S to prevent double feeding of the document S. It is something to do.

Between the sending roller 213 and the paper feeding roller 223,
A shaft 231 is rotatably disposed parallel to these shafts 212 and 221, and a pair of cams 232 are fixed to the shaft 231 at positions corresponding to the pair of support arms 211 described above. These cams 232 each have an actuating projection 234
This operating protrusion 234 is connected to the support arm 2.
By engaging with the stepped portion 214 formed at the base end of the support arm 211, the support arm 211 can be restrained in a folded position above the document S.

The feed roller 213 is moved from the shaft 221 on the paper feed roller 223 side by a timing belt 235 that is passed around toothed pulleys 215 and 225 that are respectively attached to the shaft 212 that supports the feed roller 212 and the shaft 221 of the paper feed roller 223. Driving force is transmitted.

Note that a detector 240 similar to the detector 181 attached to the document supply table 14 is provided downstream of the paper feed roller 223 in order to detect that the document S has been fed.

[Original holding means B]

The explanation will be given again with reference to FIGS. 2, 3, and 5.

First, referring to FIG. 2, document holding means B has a substantially box-like shape with a space 24 on the lower surface side. In this space 24 on the lower surface side, a white sheet member 26 is provided to cover the document S from the back side so that a toner image is not formed on the non-image area or the outside of the document, and to scatter exposure light during exposure. It is attached to a support member 28 provided in the. The white sheet member 26 and the contact glass 6 are positioned with a gap (for example, about 1 mm) that does not hinder the conveyance of the document S when the document holding means B is in the closed position. In addition, as shown in FIG. 2, the white sheet member 26 has a plurality of rollers on the left side in the figure so that the document conveyance roller 22 (described later) can contact the contact glass 6 when the document holding means B is in the closed position. A notch 29 is formed.

Further, in the closed position, the side wall portion 31 of the approximately box-shaped document holding means B is arranged so as to surround the white sheet member 26 in order to prevent exposure light from leaking outside during a copying operation. It is formed.

On the other hand, referring to FIG. 3, the upper surface of the document holding means B has a document accommodating portion 18 that is composed of a substantially planar floor portion 34 and a plurality of lips 36 attached to the floor portion 34. There is.

The rib 36 attached to the floor portion 34 is connected to the document storage portion 1.
In order to make it easier to pick up the originals stored in the
This is to make it rise somewhat above the floor part 34.

Next, referring to FIG. 5, the interior space 24 of the approximately box-shaped original holding means B is located on the left side in the figure, that is, the original holding means B
A recess 38 is formed at a position adjacent to the paper feeding mechanism 16 described above in the closed position. The document S is conveyed into the recess 38 between the white sheet member 26 of the document holding means B and the contact glass 6, and the document S is stored in the document holding section formed on the upper surface of the document holding means B after copying is completed. 18
A document conveyance/discharge means C for discharging the document S to is attached.

[Document transport and discharge means C]

Referring to FIG. 5, the document conveying and discharging means C mainly includes a document conveying roller 22 that can rotate in forward and reverse directions for conveying or discharging the document S, and a discharge roller 30 that is in contact with the document conveying roller 22. , a roller pair moving means 40 for moving the roller pair 20 constituted by these two types of rollers upward in the figure, and a detecting means 42 for determining the timing of operation of this moving means.

The document conveyance roller 22 is attached to a substantially central portion of a shaft 50 provided in the recess 38 of the document holding means B. Also,
Referring to FIG. 6, this document conveyance roller 22
A main roller 23 for transmitting the main driving force to the main roller 23 and a tube 52, 53 extending outward from the roller 23 in such a way that the shaft 50 is fitted around the main roller 23 are provided at the tips of the tubes 52 and 53, and are provided at the tip of the main roller 23 for transmitting the main driving force to the main roller 23. It consists of two auxiliary rollers 25 to improve performance. By adopting such a configuration, the auxiliary roller 25 is configured to be able to swing freely relative to the main roller 23. When conveying the document S, it is only necessary to lightly contact the document for the purpose of assisting the directionality of the document S, and like the main roller 23, it is possible to efficiently transmit the driving force to convey the document S. This is because there is no need to apply a strong contact force to the contact glass 6.

Next, returning to FIGS. 1a and 1b, the roller pair 20 consisting of the document transport roller 22 and the discharge roller 30 as described above is moved by the roller pair moving mechanism 40 so that the document transport roller 22 can be separated from the contact glass 6. has been adopted.

The moving mechanism 40 is provided at the ends of a shaft 50 of the document transport roller 22 and a shaft 51 of the discharge roller 30, and includes an idle gear 30 for transmitting driving force to the shaft 50 of the document transport roller 22.
A rotating plate 54 that can be rotated around a shaft 57 to which a rotor 6 is attached, and a solenoid 56 for rotating this plate 54 are constructed. Specifically, play gear 3
A pin 58 is provided at the lower end of the swing plate 54 which is rotatable via a bearing 55 with respect to the shaft 57 of the 06, and a solenoid 56 is connected to this pin 58.

The plate 54 is also spaced at a predetermined distance from the shaft 57 of the idle gear 306 (specifically, the shaft 57 of the idle gear 306 and the shafts 50 of each of the document conveyance roller 22 and discharge roller 30).
Elongated holes 64 and 65 are formed at a distance of 51 mm from each other, and bearings 60.degree. 61 are mounted in these elongated holes 64 and 65 while being urged downward. The shaft 5 has the document conveying roller 22 and the ejecting roller 30 attached to the bearings 60 and 61.
0.51 is attached to each.

According to the above-described configuration, the document transport roller 22 is pressed against the contact glass 6 with a desired pressure, and the gear 306 transmits the driving force to the document transport roller 22 and the gear 306 transmits the driving force to the discharge roller 30. This means that even during the turning operation, the pair of rollers 20 can also move without maintaining the threaded relationship between the peripheral surface of the teeth of the idler gear 306.

Thus, when the solenoid 56 is energized, the turning plate 54 turns counterclockwise in the figure about the shaft 57 of the idler gear 306, and the pair of rollers 20 are moved upward while maintaining their driving relationship.

As a result, the conveyance roller 22 attached to the shaft 50 is spaced apart from the contact glass 6.

The roller pair moving means 40 described above can be provided at both ends of the shaft of the roller pair 20, but by using a known ball bearing at one end of the roller shaft, it can be provided only at the other end. It is also possible to do so.

On the downstream side in the document discharge direction of the roller pair 20 including the document transport roller 22 and the discharge roller 30 having the roller pair moving means 40 configured in this manner, a micro switch is provided as a detection means 42 for detecting discharge of the document. It is provided. If the solenoid 56 is excited by the signal from the microswitch 42, it is possible to realize the movement of the roller pair 20 at an appropriate timing.

In addition to the microswitch shown in the figure, the detection means 42 for detecting the ejection of the document S includes a pressure sensor provided at the end of the shaft 50 that reads the pressure change caused by the nip of the document S by the pair of rollers. Method and discharge path 70
It is possible to appropriately employ an optical sensor or the like that is provided along the document and can optically read the presence or absence of a document.

From the document transport roller 22 to the roller 22 and the discharge roller 30
A discharge path 70 for guiding the conveyance of the document S is curved between the document conveyance roller 22 and the inner surface of a recess 38 formed in a shape along the circumferential surface of the roller 22 to the nip position. It is formed as a shape. This upper end portion is opened toward the top of the document holding means B.

The reversely fed document S is placed at the lower end of this ejection path 70.
A guide means 71 is provided for guiding to zero.

This guide means 71 has a thickness of, for example, 00.075 mm.
The contact glass 6 is made of a flexible piece of synthetic resin such as a polyester film, and is provided to prevent the document S from being discharged from the contact glass 6 onto the document supply table 14 . Therefore, when the document transport roller 22 rotates in the reverse direction,
The document S is deflected upward by the guide means 71.

[Drive means D]

As shown in FIG. 6, the driving source of the driving means is composed of a reversible C motor 510, and a gear 511 and a separation roller 22 attached to this DC motor 510.
A gear 242 provided through a one-way clutch 241 (see FIG. 8) meshes with the shaft 222 of the paper feed mechanism 16, thereby transmitting a driving force for rotationally driving the sheet feeding mechanism 16.

Further, as shown in FIGS. 6 to 8, the gear 511 of the DC motor 510 is connected with a rotational drive transmission system 49 having a plurality of idle gears, and the document is transmitted through the rotational drive transmission system 49. Gear 30 provided on shaft 50 of conveyance roller 22
3 is rotationally driven.

As shown in FIG. 7, the shaft 50 of the document transport roller 22 is provided with an electromagnetic clutch 32 so that the rotation of the shaft 50 can be stopped even though the gear 303 is rotating. The gear 303 is connected to the shaft 51 of the discharge roller 30.
The discharge roller 30 is attached to the shaft 51 via a one-way clutch 461 that is provided inside the discharge roller 30 and is driven only when the document conveyance roller 22 is reversed.

The paper feeding mechanism 16 is driven by the ninth drive transmission gear train.
As shown in the figure, the gear 226 provided on the other end of the shaft 222 of the separation roller 224 is connected to the gear 2 provided on the shaft 221 of the paper feed roller 223 via an idle gear 226a.
27 are engaged and transmitted. In this gear 227, when the solenoid 228 is energized for a very short time, the solenoid pawl 228a is disengaged from the locked projection 229a, and the spring clutch 2.29 is no longer connected. At this time, in order to return the solenoid pawl 228a to its original position in a short time,
When the spring clutch 229 rotates only once, the solenoid pawl 228a is once again locked to the locked protrusion 229a, and the clutch 229 is disconnected.

A gear 236 integrated with a spring clutch 229 is attached to the gear 227, and the gear 236 has the following functions:
A cam 232 (see FIG. 1a) is engaged via an idle gear 237. Therefore, the spring clutch 2
29 is connected, the shaft 231 rotates, and the operating protrusion 234 of the cam 232 attached to this shaft 231 comes off the step 214 of the support arm 211, and the support arm 211
rotates downward, and the document S is rotated while the feed roller 213 is rotated.
The document S falls upward, and feeding of the document S begins.

As shown in FIG.
．． 524 are arranged. This support plate 521 is resiliently biased from above. Therefore, when the document holding means B adjacent to the document supplying means A is closed,
The gear 303 of the document transport roller 22 is connected to the rotational drive transmission system 49.
When meshing with the gear 303, the tooth tips of the idle gear 306 of the gear 303 and the idle gear 524 overlap, and the support plate 521
Rotate slightly downward. Then, when the idle gear 524 starts to rotate, the two engage, the support plate 521 is lifted, and the driving force is continuously transmitted.

[Automatic document feeder operating system]

Next, the operation of the automatic document feeder will be described with reference to FIGS. 6, 8, and 10a to 10C, and the timing chart of FIG. 11.

When a sheet-shaped original S is placed on the original supply table 14, the detector 181 of the original supply table 14 is closed, and a signal indicating that the original S to be copied is present on the original supply table 14 is output. . When this signal is output, scanning of the print start button PS (see FIG. 2) is permitted, and when this button PS is pressed, the DC motor 510 starts normal rotation. A short time L1 for the rotation of the DC motor 510 to become stable
After a delay (about 150 ms), the solenoid 188 that rotates the document restraining member 185 is energized, and feeding of the document S is permitted.

Further, when the gear 242 rotates from the gear 511 of the DC motor 510 and the shaft 222 rotates via the one-way clutch 241 (see FIG. 8), the gear 242 fixed to the other end side rotates.
26, the gear 227 of the paper feed roller 221 starts rotating. At the same time, the solenoid 228 is excited for a short time t3 (about 150 ms) at time t2 (about 300 ms), which is more than the above-mentioned time t1 after the button PS is pressed, and the spring clutch 229 provided in the gear 227 is connected. . When this spring clutch 229 is connected, as described above, the cam 232 rotates, the delivery roller 213 rotates and falls onto the document S, and one document S is sent toward the paper feed roller 223. do.

The fed document S is continuously conveyed by the paper feed roller 223 in the direction of the document transport roller 22, and the detector 240 is turned on by the document S (see FIG. 10(a)). At this time, since the separation roller 224 rotates in the opposite direction to the conveyance direction of the document S, if the second or subsequent documents S are fed in duplicate, their movement can be prevented.

In this way, the paper feeding mechanism 16 can feed the document S until the leading edge of the document S contacts the document transport roller 22, and even if the document S contacts the document transport roller 22, the document S can be fed until the leading edge of the document S contacts the document transport roller 22. Since the rotation of the document S is slightly continued, the document S faces the document conveyance roller 22, and the posture of the document S is corrected. A state in which the original S is in contact with the original transport roller 22 is shown in FIG. 1O. Further, t4 indicates the time from when the leading edge of the document S comes into contact with the document conveyance roller 22 after the detector 240 is turned on, and after the DC motor 510 starts normal rotation, the rotation of the document conveyance roller 22 starts. The time until the start is indicated by the symbol A in FIG.

After the detector 240 is turned ON and a predetermined time t4 has elapsed, the electromagnetic clutch 32 for starting the rotation of the document conveyance roller 22 is activated, and conveyance of the document S onto the contact glass 6 is started.

At the same time, a pulse counter 33 having a low encoder provided on the shaft 50 of the document transport roller 22 counts the number of pulses nl from the time when the electromagnetic clutch 32 is activated until the time when the detector 240 is turned off. The length of the document S corresponding to this number of pulses nl corresponds to the length obtained by subtracting the length from the detector 240 to the document transport roller 22.

The connection time of the electromagnetic clutch 32 is determined by the O of the detector 240.
The time required to count the predetermined number of pulses n2 (corresponding to the length from the detector 240 to the document transport roller 22) from the time of FF and the rotational inertia of the rollers and gears to completely stop them. Therefore, the time is the sum of the time t5 required to slightly reverse the DC motor 510. When the electromagnetic clutch 32 is disengaged, the document S is placed at a predetermined position on the contact glass 6, and the document S
The rear end is located at the lower end of the document transport roller 22,
This state is shown in FIG. 10, and this time is indicated by the symbol B in FIG.

When exposure scanning of the original S is completed and copying is completed, the DC motor 510 starts reverse rotation, and at the same time, the electromagnetic clutch 3
2 is also connected again (however, the electromagnetic clutch 32 may also be connected during exposure scanning). When the DC motor 510 reverses, the document transport roller 22 rotates in the opposite direction to the direction in which the document S was transported, and the discharge roller 30 rotates the document S by connecting the one-way clutch 461.
Rotation is started in the direction of document holding means B, which is the ejection direction. Therefore, the document S is fed backwards, guided to the discharge path by the guide member 70, and then moved between the discharge roller 30 and the document transport roller 22.
(See FIG. 10d). Thereafter, the document is discharged to the upper part of the document holding means B by the discharge roller 30. Regarding this discharge,
The rear end of the document S that has passed through this nip position turns on the microswitch 42. When the solenoid 56 is energized based on the ON signal of the microswitch 42, the turning plate 54 turns counterclockwise, and this turning operation causes the document conveying roller 22 to be separated from the contact glass 6. This solenoid 56 is activated when the leading edge of the document S is completely ejected and the microswitch 42 is turned on.
It continues to be excited until it returns to the FF state. Then, the excitation is canceled based on the OFF signal of the microswitch 42, and the document conveyance roller 22 also returns to its original state.

On the other hand, the electromagnetic clutch 32 attached to the shaft 50 of the document transport roller 22 is operated until the leading edge of the document S passes between the discharge roller 30 and the document transport roller 22 (indicated by symbol C in FIG. 11). The connection is disconnected after the document S passes through the above-mentioned section. As a result, the document transport roller 2
2 becomes freely rotatable when the electromagnetic clutch 32 is disconnected, so that it rotates following the rotation of the discharge roller 30.

The DC motor 510 operates at least while the ejection roller 30 is ejecting the original S, that is, during the time period corresponding to the pulses n1 and n2, plus the time for the original S to pass half a turn around the original transport roller 22. It is rotated in the opposite direction (indicated by C and D in FIG. 11).

Note that when the document S is ejected, the paper feeding mechanism 16 is entirely stopped by the separation roller 224.

The transporting and ejecting operations for one original document S are as described above, but while the original document S is placed on the original supply table 14, the originals are fed one by one, and the transporting, copying, and ejecting operations are performed one by one. Repeated.

[Modified example]

In the above embodiment, the time for separating the document conveyance roller 22 from the contact glass 6 was simply linked to the time when the switch of the detection means 42 was turned on. Based on the document size signal detected at , a lag time is set from when the detection means 42 of the document conveyance/discharge means C is turned on until just before the leading edge of the document S passes through the contact position between the document conveyance roller 22 and the contact glass 6. can be set so that the document transport roller 22 is separated from the contact glass 6 immediately before this passage.

Further, in the above specific example, the ejection roller 30 and the document transport roller 22 are brought into contact with each other, and the pair of rollers 20 is moved. However, apart from this specific example, the following modifications can be considered.

As a first modification, consider a roller pair 601 of the discharge roller 30 and another driven roller 600, unlike the roller pair 20 described above. in particular,
Referring to FIG. 12, which schematically shows the moving means and gear train, the drive transmission system from the DC motor to the document transport roller 22a is exactly the same as in the above specific example, and the rotating plate (the above specific example) is used. Swivel plate 5 in example
A moving means 40a consisting of a mechanism (same as 4) 54a and a solenoid 56a is provided only for the document conveyance roller 22a, and moves the document conveyance roller 22a in a planetary manner while maintaining a screwed relationship with the gear 306. On the other hand, the drive is transmitted to the discharge roller pair 601.
For example, there is an idle gear 6 in the middle so as to drive one of the
05 to a gear 606 attached to the shaft 51a of the discharge roller 30a. By doing so, roller vs. 60
The other roller 600 of 1 can be a driven roller. According to this configuration, unlike the above specific example,
Only the document transport roller 22a can be moved, and the moving torque of the solenoid 56a used in the moving mechanism can be made smaller.

The control of the moving mechanism in this modification may basically be performed at exactly the same timing as in the above specific example. In addition,
In this modification as well, a gear 303a is attached to the shaft 50a of the conveyance roller 22a via an electromagnetic clutch (not shown), and this electromagnetic clutch can be activated at any time in the same manner as in the above-described specific example.

In the second modification, the configuration of the roller pair for ejecting is the same as the roller pair 20 in the above specific example, consisting of an ejecting roller 30 and a document transport roller 22, and this roller pair is used only when ejecting the document. They are placed in contact with each other so that the document is nipped. Referring to FIG. 13, which shows a gear train simplified as pS in the same way as in the first modification, document conveyance roller 2
2b and the discharge roller 30b forming the roller pair 20b as driven rollers, the rotating plate 54b in the moving mechanism is operated by the solenoid 56b, and the document conveyance roller 22b is rotated and moved. In this case, the drive transmission to the document transport roller 22b may be exactly the same as in the above specific example, and only the ejection roller 30b is separated from the gear train. During this movement, the document transport roller 22b and the discharge roller 30b are brought into contact with each other. In this case, the shaft 51b of the discharge roller 30b is connected to the main body side plate 62b.
It is movably attached via a bearing 67b to a long hole 65b provided in the document transport roller 2 using a spring 69b.
2b side (lower side in the figure).

By doing this, when the document transport roller 22b is moved upward and brought into contact with the ejection roller 30b,
The pair of rollers 20b can be brought into contact with each other smoothly.

Regarding the control relationship in the case of the second modification, since no electromagnetic clutch is used for the shaft 50b of the document transport roller 22b, the control is basically completely the same as in the above specific example except for the control related to the electromagnetic clutch. good.

By using the modification described above, the configuration can be further simplified and the object of the present invention can be achieved.

(Effects of the Invention) As described above, according to the automatic document feeder of the present invention, in the automatic document feeder of a simple structure using a document feed roller that can rotate in forward and reverse directions, the document It is possible to provide an automatic document conveyance device in which no friction noise is generated between the conveyance roller and the contact glass, and there is no uneven wear of the document conveyance roller.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating an automatic document feeder according to an embodiment of the present invention, in which FIG. A perspective view of an electrostatic copying machine; FIG. 4 is a perspective view of the automatic document feeder;
5 is a cross-sectional view of the automatic document feeder, FIG. 6 is a plan view of the automatic document feeder, FIG. 7 is a cross-sectional view of the document feed roller side, and FIG. 8 is a partial rear view of the drive means. 9 is a partial front view of the driving means, FIGS. 10a to 10d are cross-sectional views explaining the operation of the automatic document feeder, FIG. 11 is a timing chart showing the operation of the automatic document feeder, and FIG. 13 and 13 are views for explaining an automatic document feeder according to a modified example of the present invention. Reference numbers in the figure represent the following contents. 14... Original supply table, 16... Paper feeding mechanism, 22...
・Document transport roller, 30... Ejection roller, 70...
Ejection path, A...Document supply means, B...Document holding means, C...Document transport and discharge means, D...Driving means, S.
...Manuscript. Patent applicant: Mita Kogyo Co., Ltd.

Claims (3)

[Claims] (1) A document supply unit equipped with a paper feeding mechanism that feeds the document on the document supply table upward to the document placement plate; a document storage section that accommodates the document on which an image has been formed on its upper surface; and an image forming section. a document holding means comprising a document covering sheet member that sometimes covers the back side of the document; and a document formed to be rotatable in forward and reverse directions for conveying the document fed from the document supplying device to a predetermined position on the document placement plate. a conveyance roller, a discharge path for guiding the document conveyed by the document conveyance roller to the document storage section, a discharge roller provided in the discharge path, and an end of the document passing through a nip position of the conveyance roller. a document conveying/discharging means comprising: a detecting means for detecting that the document has been transferred; and a moving means for moving the document conveying roller away from the document placing plate based on the detection by the detecting means; the document feeding means and the document conveying means; An automatic document feeder comprising: a drive means for driving an ejection means; (2) The ejection roller in the document conveyance/ejection means is in contact with the document conveyance roller, and when the detection means detects that the document is nipped by the pair of rollers consisting of the ejection roller and the document conveyance roller, the moving means starts conveying the document. 2. The automatic document feeder according to claim 1, wherein the roller pair is moved so that the roller is separated from the document placement plate. (3) The discharge roller in the document conveyance and discharge means forms a separate pair of rollers independently of the document conveyance roller,
2. The automatic document conveyance system according to claim 1, wherein the detection means detects that the document is nipped by the pair of conveyance rollers, and the moving means moves only the document conveyance rollers away from the document placement plate. Device.