JP2008254835A - Automatic document carrying device in image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic document carrying device in an image forming device preventing hanging and dropping down of a long document when the long document is placed. <P>SOLUTION: The automatic document carrying device in the image forming device is provided with a paper feeding side document tray 10 having a paper feeding side auxiliary tray 12 capable of being expanded/contracted in the paper carrying direction with respect to a paper feeding side main tray 11; a paper feeding side expanding/contracting operation device 14 for expanding/contracting the paper feeding side auxiliary tray 12; a paper feeding side expanding/contracting position detecting device for detecting the expanding/contracting position of the paper feeding side auxiliary tray 12; and an expanding/contracting control means for performing expanding/contracting operation of the paper feeding side expanding/contracting operation device 14 so that the expanding/contracting position of the paper feeding side auxiliary tray 12 detected by the paper feeding side expanding/contracting position detecting device corresponds beforehand to the length in the carrying direction of a document placed on the paper feeding side document tray 10. This configuration can prevent a long document from being hung and dropped from the paper feeding side document tray 10 and dirtied and damaged. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an automatic document feeder in an image forming apparatus including a paper supply side document tray and a paper discharge side document tray.

  2. Description of the Related Art Conventionally, when continuously copying a plurality of originals to an image forming apparatus such as a copying machine, the originals placed on the original paper supply table for paper supply are sequentially taken out one by one, and image information is stored. 2. Description of the Related Art An automatic document feeder that discharges a document that has been read onto a document discharge table for discharge is used.

  In such an automatic document feeder, in order to reduce the size of itself, each table can be loaded with a standard size document sheet such as B5 size, B4 size, or A4 size. It is formed in the minimum necessary size. (See Patent Document 1)

  However, if, for example, an A3-size long original sheet or the like is placed on each table, the rear end of the long original sheet protrudes from the table and hangs down by its own weight. You have a problem that you need.

JP-A-9-464727

  SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic document feeder in an image forming apparatus that prevents a long document sheet from dropping due to a droop when a long document sheet is placed on a tray on which document sheets are stacked. is there.

Means for Solving the Problems and Effects of the Invention

  In order to solve the above problems, an automatic document feeder in an image forming apparatus of the present invention includes a paper feed side main tray and a paper feed side auxiliary tray, and the paper feed side auxiliary tray serves as the paper feed side main tray. On the other hand, a paper feed side document tray that can be expanded and contracted in the paper transport direction, a paper feed side telescopic operation device that expands and contracts the paper feed side auxiliary tray of the paper feed side document tray, and a paper feed side document tray A paper feed side expansion / contraction position detection device for detecting the expansion / contraction position of the paper side auxiliary tray, and the expansion / contraction position of the paper supply side auxiliary tray detected by the paper supply side expansion / contraction position detection device are placed on the paper supply side document tray. Expansion / contraction control means for expanding / contracting the sheet feeding side expansion / contraction operation device so as to correspond to the length of the original document in the conveyance direction.

  With the above configuration, it is possible to prevent the long original paper from dripping from the paper supply side original tray, to prevent it from becoming dirty or damaged, and to extend the extension side of the paper supply side auxiliary tray to the long original paper. Since the adjustment can be automatically performed together, it takes less time and the paper feeding side auxiliary tray does not become unnecessarily long, so that the space can be regulated.

  In addition to the above configuration, the automatic document feeder in the image forming apparatus further includes a sheet-feed-side sheet detection device that detects the presence or absence of document sheets placed on the sheet-feed-side document tray. The paper feeding side expansion / contraction operation device is extended and contracted so as to correspond in advance to the length of the original paper placed on the document tray in the conveying direction, and paper feeding is performed when the paper feeding side paper detection device no longer detects the original paper. Feeding side expansion / contraction control that operates the side expansion / contraction operation device and causes the expansion / contraction operation device to degenerate so that the expansion / contraction position of the paper feeding side auxiliary tray detected by the paper feeding side expansion / contraction position detection device returns to the expansion / contraction origin. And means.

  With the above configuration, when a long document sheet is not used, the paper feeding side auxiliary tray has been returned to the expansion / contraction origin, so that it does not interfere when handling a standard size document sheet, and has a compact form. Can be maintained.

  Further, by providing a paper discharge side document tray having the same function as that of the paper supply side document tray of the automatic document feeder in the image forming apparatus, even if there is a long document sheet to be discharged, the paper discharge side document tray It can be prevented from getting dirty from being dropped or damaged, and the expansion / contraction position of the output side auxiliary tray can be adjusted automatically according to the long original paper. In addition, since the auxiliary tray on the paper discharge side does not become long, the space can be restricted. Further, when the long original paper is not used, the discharge side auxiliary tray is returned to the expansion / contraction origin, so that it is possible to maintain a compact form without disturbing the handling of the standard size original paper.

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, embodiments of the present invention will be described with reference to examples shown in the drawings. 1 and 2 are external perspective views showing an automatic document feeder in the image forming apparatus according to the present invention, and FIG. 3 is an external side view showing the automatic document feeder. In FIG. 1, an image forming apparatus 1 is a copying machine, and is composed of an image forming apparatus main body 2 mainly having a copying function and an automatic document conveying apparatus 3 mainly having a function of conveying document paper W.

  The automatic document feeder 3 is rotatably provided on the rear side of the image forming apparatus main body 2 via a hinge mechanism 2a. When placing the document paper W on the contact glass 2b provided on the upper surface of the image forming apparatus main body 2, the automatic document feeder 3 is rotated upward as shown in FIG. In order to hold down W, it is possible to rotate downward. This upwardly rotated state is held in a state where freedom is restricted at an arbitrary position. The automatic document feeder 3 includes a paper feed-side document tray 10 on which document paper W is stacked and a paper-discharge-side document tray 20 on which the document paper W from which image information has been read is discharged and stacked. Arranged at predetermined intervals, the paper supply side document tray 10 is inclined upward toward the upstream side in the paper transport direction X, and the paper discharge side document tray 20 is provided in a substantially horizontal state.

  As shown in FIGS. 3 and 4, the automatic document feeder 3 takes out the document paper W placed on the feeding-side document tray 10 one by one by the pickup roller 3 a and puts it in the automatic document feeder 3. A function is provided for reading the image information of the original paper W in the capture and transport process, and finally discharging the original paper W on which the image information has been read onto the paper output side original tray 20.

The paper supply side document tray 10 is housed inside the paper supply side main body tray 11 that is fixedly arranged and the paper supply side main body tray 11 and is provided so as to be extendable in the front and rear directions in the paper transport direction X. The side auxiliary tray 12 is provided. The paper feed side document tray 10 is provided with a side guide 10 a for restricting the positional deviation of the document paper W in a direction orthogonal to the paper transport direction X.
Further, the loading length L1 in the paper feeding side main body tray 11 in the state in which the paper feeding side auxiliary tray 12 is housed in the paper feeding side main body tray 11 is A4 size according to the JIS standard. Is a standard size original paper W, when the longitudinal direction of the original paper W is placed along the paper transport direction X, it can be stably placed longer than the length of the original paper W in the longitudinal direction. I have to.

  As shown in FIG. 5, the sheet feeding side auxiliary tray 12 includes a first auxiliary tray 12a and a second auxiliary tray 12b. The first auxiliary tray 12a is housed in the sheet feeding side main body tray 11. The first auxiliary tray 12a is provided so as to be extendable and retractable so as to enter and exit the paper feeding side main body tray 11 in the paper transport direction X. The second auxiliary tray 12b is accommodated in the first auxiliary tray 12a. The second auxiliary tray 12b is provided so as to be extendable and retractable with respect to the second auxiliary tray 12a so as to enter and exit in the paper transport direction X.

  In this way, the sheet feeding side auxiliary tray 12 composed of the two first auxiliary trays 12a and the second auxiliary tray 12b is extended from the sheet feeding side main body tray 11 to the upstream side in the sheet conveying direction X by the maximum length. In this state, the lengths of the first auxiliary tray 12a and the second auxiliary tray 12b with respect to the standard size (A4 size) original paper W are substantially equal to the placement length L1 of the paper supply side main body tray 11. In this case, the total length L2 of the tray is extended to about three times the length. In addition, although the 1st auxiliary tray 12a and the 2nd auxiliary tray 12b are comprised with 2 bodies, it is not limited to this structure, 1 body or 3 bodies or more are possible.

  The paper supply side document tray 10 is provided with a paper supply side extension holding unit 13 for holding the first auxiliary tray 12a and the second auxiliary tray 12b of the paper supply side auxiliary tray 12 extended to the maximum length. It is done. In addition, the first auxiliary tray 12 a and the second auxiliary tray 12 b of the paper supply side auxiliary tray 12 are extended to the maximum length in the paper supply side document tray 10, or the paper supply side auxiliary tray 12 is provided with a paper supply side auxiliary tray 12. A sheet feeding side expansion / contraction operation device 14 is provided for operating the tray 12 to retract so as to accommodate the first auxiliary tray 12a and the second auxiliary tray 12b.

As shown in FIG. 6, the sheet-feeding side extension holding unit 13 includes a sheet-feeding side engagement provided at the upstream end in the sheet transport direction X in the sheet-feeding main body tray 11 and the first auxiliary tray 12 a. The concave portion 13a and the paper feeding side engaging convex portion 13b disposed at the downstream end in the paper transport direction X are configured. The sheet-feeding side engaging recess 13a and the sheet-feeding side engaging projection 13b of the sheet-feeding side extension holding unit 13 are in a state in which the first auxiliary tray 12a and the second auxiliary tray 12b are stored in the sheet-feeding side main body tray 11. In not engaged, it engages in the state extended to the maximum length.
This engagement state is smoothly engaged by an operating force for moving the first auxiliary tray 12a and the second auxiliary tray 12b by the sheet feeding side expansion / contraction operation device 14. The first auxiliary tray 12a and the second auxiliary tray 12b are prevented from being released from engagement due to their own weight or an external force that is smaller than the operation force applied by the paper supply side expansion / contraction operation device 14. Further, as another example of the sheet feeding side extension holding part 13 by the sheet feeding side engaging concave part 13a and the sheet feeding side engaging convex part 13b, as shown in FIG. 7, the attractive force of the sheet feeding side magnet 13c is used. It is also possible to do.

As shown in FIG. 8, the sheet feeding side telescopic operation device 14 includes first and second rack rails 15a and 15b, and first and second pinion gears 16a engaged with the first and second rack rails 15a and 15b. 16b, and first and second drive motors 17a and 17b connected to the first and second pinion gears 16a and 16b.
The first and second drive motors 17a and 17b are fixedly provided on the sheet feeding side main body tray 11 side. First and second rotary shafts 18a and 18b are connected to the first and second drive motors 17a and 17b, respectively. The first and second rotary shafts 18a and 18b are provided on the paper feed side main body tray 11 so as to be orthogonal to the paper transport direction X and coaxially disposed so as to be pivotally supported.

  First and second pinion gears 16a and 16b are fixed to the first and second rotating shafts 18a and 18b, respectively. The first rack rail 15a meshing with the first pinion gear 16a is fixedly provided on the first auxiliary tray 12a side along the paper transport direction X. Further, the second rack rail 15b that meshes with the second pinion gear 16b is fixedly provided on the second auxiliary tray 12b side along the paper transport direction X.

  The second rack rail 15b is kept in mesh with the second pinion gear 16b when the second auxiliary tray 12b is housed in the first auxiliary tray 12a. On the other hand, the state where the second auxiliary tray 12b is extended to the maximum length from the first auxiliary tray 12a (the paper feeding side engaging concave portion 13a and the paper feeding side engaging convex portion 13b of the paper feeding side extension holding portion 13 are engaged. 9), the second pinion gear 16b is disengaged from the second rack rail 15b, or the second drive motor 17b that rotates the second pinion gear 16b is not driven, as shown in FIG. If free rotation is possible in the state, the second rack rail 15b and the second pinion gear 16b may be in a state where the meshing state is maintained.

  The first rack rail 15a is in a state where the first auxiliary tray 12a is accommodated in the paper supply side main body tray 11, or the first auxiliary tray 12a is extended from the paper supply side main body tray 11 to the maximum length. Regardless of the state (the state in which the paper feed side engagement concave portion 13a and the paper feed side engagement convex portion 13b of the paper feed side extension holding portion 13 are engaged), the meshing state with the first pinion gear 16a is always maintained. .

  As an extension operation by the sheet feeding side expansion / contraction operation device 14 configured as described above, when the second drive motor 17b is driven to rotate, the second rack rail 15b meshing with the second pinion gear 16b is upstream of the sheet conveying direction X. Moved to the side. Thus, the second auxiliary tray 12b to which the second rack rail 15b is fixed is extended from the first auxiliary tray 12a by a predetermined amount. When the extension amount is the maximum, this state is held by the engagement of the paper feed side engaging concave portion 13a and the paper feed side engaging convex portion 13b of the paper feed side extension holding portion 13. Thereafter, when the first drive motor 17a is driven to rotate, the first rack rail 15a meshing with the first pinion gear 16a is moved to the upstream side in the paper transport direction X. As a result, the first auxiliary tray 12a, to which the first rack rail 15a is fixed, is extended from the paper supply side main body tray 11 by a predetermined amount. Even when the second rack rail 15b and the second pinion gear 16b mesh with each other at the initial extension, the first auxiliary tray 12a is extended without any trouble as long as the second drive motor 17b is not driven. Further, when the extension amount is the maximum, this state is held by the engagement of the paper feed side engagement concave portion 13a and the paper feed side engagement convex portion 13b of the paper feed side extension holding portion 13.

  Further, as the retracting operation by the sheet feeding side expansion / contraction operation device 14, when the first drive motor 17a is driven to rotate in the direction opposite to that when extended, the first rack rail 15a meshing with the first pinion gear 16a is moved in the sheet conveying direction. Moved downstream of X. As a result, the first auxiliary tray 12 a to which the first rack rail 15 a is fixed is stored in the sheet feeding side main body tray 11. Thereafter, when the second drive motor 17b is rotationally driven in a direction opposite to that when the second drive motor 17b is extended, the second rack rail 15b meshing with the second pinion gear 16b is moved to the downstream side in the paper transport direction X. Thereby, the second auxiliary tray 12b to which the second rack rail 15b is fixed is stored in the first auxiliary tray 12a.

As shown in FIG. 10, the paper supply side main body tray 11 includes a paper supply side expansion / contraction position detection device that detects the positions of the first auxiliary tray 12 a and the second auxiliary tray 12 b stored in the paper supply side main body tray 11. As shown, paper feed side tray position sensors 11a and 11b are provided. The paper feed side tray position sensors 11 a and 11 b are arranged on both ends of the paper feed side main body tray 11 in the paper transport direction X.
The paper feed side tray position sensor 11a is provided downstream of the paper feed direction X in the paper feed main body tray 11, and has a function of detecting whether or not the second auxiliary tray 12b is extended from the first auxiliary tray 12a. When the second auxiliary tray 12b is stored in the first auxiliary tray 12a, a detection signal is output (ON signal), and when the second auxiliary tray 12b is not stored, the detection signal is not output (OFF signal).
The paper feed side tray position sensor 11 b is provided on the upstream side of the paper transport direction X in the paper feed side main body tray 11 and detects whether or not the first auxiliary tray 12 a is extended from the paper feed side main body tray 11. The detection signal is output when the first auxiliary tray 12a is accommodated in the sheet feeding side main body tray 11 (ON signal), and the detection signal is not output when it is not accommodated (OFF signal). Function.

  As shown in FIG. 10, the paper feed side main body tray 11 has a paper feed side original sensor 19 as a paper feed side paper detection device that detects the presence or absence of the original paper W placed on the paper feed side main body tray 11. Is provided. The paper feed side document detection sensor 19 is arranged on the downstream side in the paper transport direction X in the paper feed side main body tray 11. A detection signal is output (ON signal) when the document sheet W placed on the sheet supply side main body tray 11 is detected by the sheet supply side document detection sensor 19, and when it is not detected, no detection signal is output ( OFF signal).

Next, as shown in FIG. 8, a sheet feeding side expansion / contraction control means 19 as an expansion / contraction control means for extending the sheet feeding side expansion / contraction operation apparatus 14 is provided with a sheet feeding side tray position sensor as a sheet feeding side expansion / contraction position detecting apparatus. 11a, 11b and the first and second drive motors are electrically connected.
Further, the expansion / contraction positions of the first auxiliary tray 12a and the second auxiliary tray 12b in the paper supply side auxiliary tray 12 detected by the paper supply side tray position sensors 11a and 11b are supplied as detection signals (ON signal or OFF signal). Input to the expansion / contraction control means 19. In addition, the original placement state detected by the paper supply side original sensor 19 is input as a detection signal (ON signal or OFF signal).
A long document sheet W1 that is longer than a standard size (A4 size) document sheet W as a sheet to be placed on the sheet supply side document tray 10 is the total length L2 of the sheet source document tray 10. The first auxiliary tray 12a and the second auxiliary tray 12b are extended by rotating the first and second drive motors 17a and 17b so as to correspond to the length (for example, A3 size, B3 size) in advance.

  In order to place the long original paper W1 (for example, A3 size) on the paper supply side original tray 10, after selecting the use of the irregular size in advance, the use of the long original paper W1 (for example, A3 size) is selected. Then, the paper feed side expansion / contraction control means 19 confirms the presence or absence of paper on the paper feed side document tray 10 by the paper feed side document detection sensor 19, and if it is determined to be “present”, the long document paper W1 (for example, The first and second drive motors 17a and 17b are rotated so as to correspond to the length of the A3 size in advance, and the first auxiliary tray 12a and the second auxiliary tray 12b are extended to fly from the paper supply side main body tray 11. The total length L2 of the paper supply side original tray 10 is extended. When it is determined that the long original paper W1 is transported and the paper on the paper supply side original tray 10 is “None”, the first and second drive motors 17a and 17b are rotated to operate the first auxiliary. The telescoping position of the paper feed side auxiliary tray 12 is set so that the tray 12a and the second auxiliary tray 12b are retracted and stored in the paper feed side main body tray 11 and the total length L2 of the paper feed side document tray 10 is restored. Control is performed to return to the expansion / contraction origin (stored in the document tray 10 on the paper feeding side).

  In the expansion / contraction control by the paper supply side expansion / contraction operation device 14, the first auxiliary tray 12a and the second auxiliary tray 12b are contracted under the condition that both detection signals of the paper supply side tray position sensors 11a and 11b are ON. . Further, the extension of the first auxiliary tray 12a and the second auxiliary tray 12b is controlled on the condition that both detection signals of the sheet-side tray position sensors 11a and 11b are OFF. Further, degeneration or expansion control is performed on condition that the detection signals of the sheet-side tray position sensors 11a and 11b are both ON signals and OFF signals.

  Next, since the paper discharge side document tray 20 is configured in the same manner as the paper supply side document tray 10, detailed description of the positional relationship and functions is omitted, and the paper supply side document tray 10 and the paper discharge side are omitted. The correspondence between the constituent members and the document tray 20 will be described. FIG. 11 is a diagram showing the paper discharge side document tray, FIG. 12 is a diagram showing the extension engagement portion of the paper discharge side document tray, and FIG. 13 is a diagram showing another example of the extension engagement portion of the paper discharge side document tray. FIG. 14 is an explanatory view showing a telescopic operation device for the paper discharge side document tray, FIG. 15 is a diagram showing a meshed state of the rack rail and the pinion gear of the paper ejection side expansion device, and FIG. It is a figure which shows arrangement | positioning of a sensor.

  In FIG. 11, a paper discharge side original tray 20 corresponds to a paper supply side main body tray 11, a paper supply side auxiliary tray 12, a first auxiliary tray 12a, and a second auxiliary tray 12b of the paper supply side original tray 10. A side body tray 21, a discharge side auxiliary tray 22, a third auxiliary tray 22a, and a fourth auxiliary tray 22b are provided.

  12 and 13, the paper discharge side main body tray 21 includes a paper supply side main body tray 11, a paper supply side engagement concave portion 13a and a paper supply side engagement convex portion 13b in the first auxiliary tray 12a, or a paper supply side magnet. The paper discharge side engaging and holding concave portion 23a and the paper discharge side engaging convex portion 23b, or the paper discharge side extending and holding portion 23 corresponding to the paper supply side extending and holding portion 13 constituted by 13c. It has.

  In FIG. 14, the paper discharge side main body tray 21 includes first and second rack rails 15a and 15b, first and second pinion gears 16a and 16b, and first and second drive motors. 17a, 17b, third and fourth rack rails 25a, 25b, and third and fourth pinion gears 26a corresponding to the sheet feeding side telescopic operation device 14 composed of the first and second rotating shafts 18a, 18b. , 26b, third and fourth drive motors 27a, 27b, and a paper discharge side telescopic operation device 24 including third and fourth rotary shafts 28a, 28b. Further, a paper discharge side expansion / contraction control means 29 for extending the paper discharge side expansion / contraction operation device 24 corresponding to the paper supply side expansion / contraction control means 19 for extending the paper supply side expansion / contraction operation device 14 is provided.

  In FIG. 15, the fourth pinion gear 26b of the paper discharge side telescopic operation device 24 is in a state of being disengaged from the fourth rack rail 25b, or the fourth drive motor 27b for rotating the fourth pinion gear 26b is not driven. If free rotation is possible in the state, the fourth rack rail 25b and the fourth pinion gear 26b may be in a state where the meshing state is maintained.

  In FIG. 16, a paper discharge side main body tray 21 includes paper supply side tray position sensors 11a and 11b provided as expansion / contraction position detection devices for the paper supply side main body tray 11, and a paper supply side document detection sensor 19 provided as a paper detection device. Corresponding to the paper discharge side tray position sensors 21a and 21b, and a paper discharge side document detection sensor 29 provided as a paper detection device.

1 is an external perspective view showing an automatic document feeder in an image forming apparatus according to the present invention. FIG. 2 is an external perspective view showing an automatic document feeder in the image forming apparatus. 1 is an external side view showing an automatic document feeder. FIG. 3 is a partial perspective view of an automatic document feeder. FIG. 4 is a diagram illustrating a document feeding side document tray. FIG. 4 is a view showing an extension engaging portion of a paper supply side document tray. The figure which shows the expansion | extension engagement part of the other example of the paper supply side original tray. FIG. 3 is an explanatory diagram showing an expansion / contraction operation device for a paper supply side document tray. The figure which shows the meshing state of the rack rail and pinion gear of an expansion-contraction operation apparatus. FIG. 6 is a diagram illustrating an arrangement of sensors on a paper supply side document tray. FIG. 4 is a view showing a paper discharge side document tray. FIG. 6 is a view showing an extension engaging portion of a paper discharge side document tray. The figure which shows the expansion | extension engagement part of the other example of the paper discharge side document tray. FIG. 3 is an explanatory view showing an extension / contraction operation device for a paper discharge side document tray. The figure which shows the meshing state of the rack rail and pinion gear of a discharge side original expansion-contraction operation apparatus. FIG. 6 is a diagram illustrating an arrangement of sensors on a paper supply side document tray.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3 Automatic document conveying apparatus 10 Paper feeding side original tray 11 Paper feeding side main body tray 11a, 11b Paper feeding side tray position sensor (extension / contraction position detection apparatus)
12 Feeding side auxiliary tray 14 Feeding side expansion and contraction operation device 19 Feeding side document detection sensor (paper detection device)
20 paper discharge side document tray 21 paper discharge side main body tray 21a, 21b paper discharge side tray position sensor (extension / contraction position detector)
22 discharge side auxiliary tray 24 discharge side expansion and contraction actuator 29 discharge side document detection sensor (paper detection device)
W Document paper X Paper transport direction

Claims (5)

A paper feed side document tray including a paper feed side main tray and a paper feed side auxiliary tray, wherein the paper feed side auxiliary tray is extendable in a paper transport direction relative to the paper feed side main tray;
A paper feed side telescopic operation device for extending and contracting a paper feed side auxiliary tray of the paper feed side document tray;
A paper feeding side expansion / contraction position detecting device for detecting an expansion / contraction position of the paper feeding side auxiliary tray of the paper feeding side document tray;
The expansion / contraction position of the paper supply side auxiliary tray detected by the paper supply side expansion / contraction position detecting device corresponds in advance to the conveyance direction length of the original paper placed on the paper supply side document tray. Expansion and contraction control means for expanding and contracting the actuator;
An automatic document feeder in an image forming apparatus.   A paper-feed-side paper detection device that detects the presence or absence of document paper placed on the paper-feed-side document tray, and the extension position of the paper-feed-side auxiliary tray detected by the paper-feed-side extension position detection device is When the paper feeding side expansion / contraction operation device is expanded and contracted so as to correspond in advance to the transport direction length of the document paper placed on the paper side document tray, and when the document paper is no longer detected by the paper feeding side paper detection device A paper feed side that operates the paper feed side expansion / contraction operation device and causes the expansion / contraction operation device to degenerate so that the expansion / contraction position of the paper supply side auxiliary tray detected by the paper supply side expansion / contraction position detection device returns to the expansion / contraction origin. 2. An automatic document feeder in an image forming apparatus according to claim 1, further comprising an expansion / contraction control means. A paper discharge-side original tray including a paper discharge-side main tray and a paper discharge-side auxiliary tray, the paper discharge-side auxiliary tray being extendable in a paper transport direction relative to the paper discharge-side main tray;
A paper discharge side expansion / contraction operation device that expands and contracts the paper discharge side auxiliary tray of the paper discharge side document tray;
A discharge side expansion / contraction position detecting device for detecting an expansion / contraction position of the discharge side auxiliary tray of the discharge side document tray;
The discharge side expansion / contraction position of the discharge side auxiliary tray detected by the discharge side expansion / contraction position detection device corresponds in advance to the length in the conveyance direction of the document paper placed on the discharge side document tray. Expansion and contraction control means for expanding and contracting the actuator;
An automatic document feeder in an image forming apparatus.   A paper discharge side paper detection device that detects the presence or absence of the original paper placed on the paper discharge side document tray, and the expansion / contraction position of the paper discharge side auxiliary tray detected by the paper discharge side expansion / contraction position detection device When the paper discharge side expansion / contraction operation device is expanded / contracted so as to correspond in advance to the transport direction length of the document paper placed on the paper side document tray, and when the document paper is no longer detected by the paper discharge side paper detection device The paper discharge side which operates the paper discharge side expansion / contraction operation device and operates the contraction operation of the expansion / contraction operation device so that the expansion / contraction position of the paper discharge side auxiliary tray detected by the paper discharge side expansion / contraction position detection device returns to the expansion / contraction origin. The automatic document feeder in the image forming apparatus according to claim 3, further comprising an expansion / contraction control unit. A document feeding side document tray according to claim 1 or 2,
A discharge side document tray according to claim 3 or 4,
An automatic document feeder in an image forming apparatus.

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