JPH1020565A - Automatic document feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic document feeder by which the position of a guide surface is easily adjusted. SOLUTION: On a placing plate 210, a referenece plate 230 having the main guide surf ace and a positioning plate 250 interposing a document between the plate 230 and positioning it in a width direction P8 are arranged. The plate 230 can be deviated along in the width direction P8 and a positioning arm 265 is fitted to the plate 250. On the arm 265, plural recessed parts 266-269 are formed at positions corresponding to the size of the document. A reference arm 232 having a click part 233 which can be engaged with the recessed parts 266-269 is integrally fitted to the plate 230. Thus, since the plate 230 can be deviated, the position of the main guide surface can be easily adjusted even when it is deviated. Besides, since a click position is also changed at the same time, the plate 250 can accurately by slid according to the size of the document.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, an automatic document feeder (hereinafter referred to as an automatic document feeder) which is mounted on an upper surface of an image forming apparatus such as a copying machine and automatically feeds a document set on a document placing portion to an image forming position. ADF: Automatic Docume
nt Feeder) is known. Usually, a guide member having a guide surface is provided on the document placing plate of the ADF. When a document is set on the document placing portion, the side edge of the document is set along the guide surface. The set document is transported along a predetermined transport path, and is set at an image forming position. At this time, the document is set along a width reference position which is a reference position in the width direction. When a document is set in such a state, a document image is formed on a sheet without displacement.

[0003]

However, when the ADF is mounted on the image forming apparatus during setup or maintenance, the correspondence between the guide surface and the width reference position may be shifted. If the correspondence between the guide surface and the width reference position deviates, the document is set with a deviation from the width reference position. As a result, the original image is formed on the paper with a shift.

Therefore, in such a case, it is necessary to adjust the position of the guide surface in order to align the guide surface with the width reference position. However, in order to adjust the position of the guide surface, it is necessary to move the ADF body. Therefore, fine adjustment is very difficult. Further, the position adjustment work is very complicated, and there is a possibility that a great burden is imposed on the user.

An object of the present invention is to solve the above-mentioned technical problems and to provide an automatic document feeder capable of easily adjusting the position of a guide surface.

[0006]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising: a document placing plate; and a document placed on the document placing plate, which is transported in a predetermined document transport direction. And a main guide surface member provided on the original placing plate, extending in the original transport direction, and having a main guide surface along one side of the original to be placed, and provided on the original placing plate,
A sub-guide surface member having a sub-guide surface provided at an interval in parallel with the main guide surface; and a sub-guide surface member so that the distance between the main guide surface and the sub-guide surface can be changed according to the document size. And a slide means that can slide the document in a direction crossing the document conveying direction. The slide means has a pair of engagement arms extending between the main guide surface member and the sub guide surface member, and One of the engagement arms of the mating arm has one end fixed to the main guide surface member,
One end of the other engagement arm is fixed to the sub guide surface member, and one of the one engagement arm and the other engagement arm is provided with one engagement portion, and the other is provided with one engagement portion. A plurality of engaged portions are provided at predetermined intervals in the length direction of the engaging arm, and when the engaging portion and any of the engaged portions are engaged, the main guide surface and the sub guide An automatic document feeder is characterized in that the surface is separated from the surface by a predetermined interval according to the document size.

According to a second aspect of the present invention, the position of the main guide surface member can be shifted in a direction crossing the original conveying direction. Device. The invention according to claim 3 is
One of the pair of engagement arms is fixed to the main guide surface member and has one projection, and the other engagement arm is fixed to the sub guide surface member and 3. The automatic document feeder according to claim 1, wherein the plurality of concave portions have a plurality of recesses engageable at predetermined intervals in a length direction of the engagement arm.

According to the present invention, when the engagement portion and the engaged portion are engaged as a result of the sliding movement of the sub guide surface member, the main guide surface and the sub guide surface are separated from each other by a predetermined distance according to the size of the document. State. Therefore, the sub guide surface member can be accurately moved according to the size of the document. Further, since the position of the main guide surface member can be shifted in a direction crossing the document conveying direction, even if the main guide surface is shifted, the position can be easily adjusted.

In addition, the engagement arm fixed to the main guide surface member of the pair of engagement arms is shifted together with the main guide surface member. As a result, the protrusion provided on the engagement arm also shifts. Therefore, even when the main guide surface member is displaced, the gap between the main guide surface member and the sub guide surface member depends on the document size when the recess provided on the other engagement arm is engaged with the projection. At a predetermined interval. That is, the length between the main guide surface member and the sub guide surface member can always be kept constant for the same document size.

[0010] The invention according to claim 4 further includes a plurality of switching means, and the other arm is a light-shielding element for turning on / off the switching means in a different combination each time the projection engages with any of the recesses. 4. The automatic document feeder according to claim 3, further comprising a member. According to the present invention, the switching unit is turned on / off in a different combination each time the projection engages with any one of the recesses, so that the document size can be detected based on the output of the switching unit.

[0011]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an internal configuration of an air-feed circulation type document feeder (hereinafter, simply referred to as “RDH”) to which an embodiment of the present invention is applied. The RDH 100 is mounted on the upper surface of the copying machine main body 50, and automatically supplies the original to the contact glass 51 provided on the upper surface of the copying machine main body 50, and returns the copied original to the original position. The original can be automatically re-supplied onto the contact glass 51.

The RDH 100 is rotatably attached to the copier main body 50. Specifically, it can be displaced between a state in which the upper part of the copying machine main body 50 is covered (a state shown in the figure) and a state in which it is released. The RDH 100 includes a document placement unit 200 for placing a document, a moving unit 300 for transferring and setting the placed document along the document transport direction P4, and a copying machine main body. A document supply unit 400 for supplying the document to the document supply unit 50; a document separation mechanism 500 for separating the set document to feed the documents one by one to the document supply unit 400;
The conveyance belt unit 600 for moving the original supplied to the zero side in the supply direction or the opposite supply direction, and the original discharge unit 70 for discharging the original from the copying machine main body 50 side.
0.

Next, the function of each part of the RDH 100 will be described generally. The document placing portion 200 has a placing plate 21 that is inclined so as to become lower toward the upstream side in the document transport direction P4.
0 is provided. For example, B5
Documents of up to A3 size can be placed. When a document is placed on the placing plate 210, the positioning plate 2 disposed opposite the reference plate 230 along the side edge of the document.
50 is manually moved in a direction perpendicular to the document transport direction P4. Thereby, the original is moved in the original transport direction P4.
Can be positioned with respect to a direction perpendicular to.

In this embodiment, the reference plate 230 corresponds to a main guide surface member, and the positioning plate 250 corresponds to a sub guide surface member. Now, when the print key for instructing the start of copying is pressed in a state where it is positioned in the direction perpendicular to the document transport direction P4, the moving unit 300
After the pressing bar 311 provided in the original pressing mechanism 310 in the inside of the moving unit 300 once retreats,
The robot stands and stands along the pivot direction P3. Then, it protrudes out of the mobile unit 300 and then falls down. As a result, the rear end of the placed document is pressed. Thereafter, the moving unit 300 moves along the moving direction P1. As a result, the document can be positioned in the document transport direction P4.

As described above, the setting of the original is completed in a state where the original is positioned in the two directions of the original transport direction P4 and the vertical direction. Reference numeral 295 denotes a document presence / absence sensor for detecting the presence / absence of a document serving as a trigger for returning the moving unit 300 to the original solid line state after the end of copying. The document set on the document placement unit 200 is guided to the document supply unit 400, and is sent out along a sheet feeding path 402 by a pair of sheet feeding rollers 401. The original sent out to the paper feed path 402 is adjusted in supply timing by a pair of registration rollers 403,
0 places it on the contact glass 51 of the copying machine body 50.

At this time, if the supplied original is a one-sided original, the copying operation by the copying machine main body 50 is executed as it is. On the other hand, if the supplied original is a two-sided original, the original is turned over before the copying machine 50 executes the copying operation. More specifically, the double-sided document placed on contact glass 51 is pulled back to reversing path 405 by transport belt unit 600. The returned document is reversed by passing through the reversing path 405 with the rotation of the conveyor belt unit 600, the pair of reversing rollers 404 and the pair of registration rollers 403, and the contact glass 51 is conveyed by the conveyor belt unit 600.
Placed again on top. Then, a copying operation is performed in this state. That is, the back side is first copied. Thereafter, the sheet is turned over again and placed on the contact glass 51 three times, and then a copying operation is performed to copy the front side.

The reason why the back side is copied first in the case of a two-sided document is to make the front side face up when returning the copied document to the original position. The document separation mechanism 500 separates a document using air before the document is guided to the document supply unit 400. The document separation mechanism 500 includes a document suction unit 510 for sucking air and sucking the lowermost document on the mounting plate 210, and a document floating unit for floating documents stacked on the sucked document by air. 550 and the sucked original is sent to the original supply unit 4.
And a document draw-in section 570 for drawing the document to the 00 side.

The document placed on the contact glass 51 is sent to the document discharge unit 700 by the conveyor belt unit 600 after a predetermined copying operation is performed by the copying machine body 50. The transport belt unit 600 is arranged to face the contact glass 51 in a state shown in the figure, and is driven by a motor (not shown). Thus, the original on the contact glass 51 is sent to the original discharge unit 700 side.

The document sent to the document discharge unit 700 is drawn into a paper discharge path 702 by a pair of paper discharge rollers 701. Thereafter, the original is sent along a paper discharge path 702 by a paper discharge roller pair 703, and the paper discharge roller pair 704, 705
, So that the document is discharged to the document placing portion 200. At this time, when the original remains on the original placing portion 200, the original is discharged onto the original. That is, the original is returned to the original position. In this way, the original is RDH100
It is circulated inside.

The moving unit 300 includes an original discharge unit 700
To go back and forth. Paper discharge path 702
Is constituted by a gap formed between the document discharge unit 700 and the moving unit 300. Further, since the moving unit 300 moves back and forth with respect to the document discharge unit 700, the discharge roller pair 705 is provided on the moving unit 300 side. Therefore, the discharge roller pair 705 moves with the movement of the moving unit 300.

FIG. 2 is a simplified plan view showing the configuration centering on the mounting plate 210. A reference plate 230 is disposed near one edge of the mounting plate 210. A positioning plate 250 that can be manually slid along the rail 251 in a direction perpendicular to the document transfer direction P4 is disposed near the other edge of the mounting plate 210 so as to face the reference plate 230. ing. A moving unit 300 is provided upstream of the mounting plate 210 in the document transfer direction P4.

When placing a document on the placing plate 210,
It is placed at the initial setting position 211 as shown by oblique lines in FIG. More specifically, the right edge and the rear edge of the original are placed along the guide surface 245 of the reference plate 230 and the moving unit 300, respectively, and the positioning plate 250 is
51, the sub guide surface 247 of the positioning plate 250 is aligned with the left edge of the document.

Returning to FIG. 2, the mobile unit 300 includes:
The driving force from the unit motor M1 is transmitted. When the driving force is transmitted from the unit motor M1, the moving unit 300 moves along the moving direction P1, as indicated by the two-dot chain line. As a result, the rear end of the document is pushed in the document transport direction P4. Thus, the document placed on the placing plate 210 can be transported along the document transport direction P4.

The transfer of the document is performed until the document is set at the supply position 212 as shown in FIG. Specifically, the process is performed until the leading end of the document is along the reference position 213 corresponding to the right end of the air duct 551. Returning to FIG. 2, downstream of the placing plate 210 in the document transfer direction P4, 6
Book pull-in belts 572,573,574,575,57
6,577 are arranged in parallel in a direction perpendicular to the document transport direction P4. Of these, the upper four pull-in belts 572 to 575 are wound around pairs of rollers 513 and 514 along the document transport direction P4. The two pull-in belts 576 and 577 on the lower side of the drawing are wound around a roller 513 and a roller (not shown).

The roller 513 is attached to a roller shaft 516. The roller shaft 516 has a belt motor M2
Is transmitted. When the belt motor M2 is driven, the roller shaft 516 and the roller 51
3 rotates along the rotation direction P5. As a result, the pull-in belts 572 to 577 rotate in the rotation direction P2. Thus, the lowermost document among the documents on the pull-in belts 572 to 577 can be pulled in along the document transport direction P4.

The pull-in belts 572 to 577 have a plurality of through holes 578 formed therein. Retraction belt 572-57
7, a suction duct 5 is provided on the mounting plate 210 facing the lower surface of the suction duct 5.
The suction port 512 to which 11 was connected is formed. Suction duct 511 is connected to suction fan 515.
The suction fan 515 is driven by a suction fan motor M3.

The suction fan 515 is connected to the suction fan motor M3.
When driven by the air, the air is sucked into the suction port 512 through the through hole 578, and finally, the suction fan 515.
Sucked into. Thereby, the pull-in belts 572 to 57
7 can be attracted to the pull-in belts 572 to 577. An air duct 551 is disposed downstream of the mounting plate 210 in the document transport direction P4. A blower fan 553 is connected to the blower duct 551. The ventilation duct 551 has a plurality of ventilation ports 55.
2 (see FIG. 1) is formed so as to face the mounting plate 210 along the vertical direction of the document transport direction P4. The blower fan 553 is driven by a blower fan motor M4.

The blower fan 553 has a blower fan motor M4.
When driven, the air is supplied from the blower fan 553 to the blower duct 551, and the air is blown obliquely from the blower port 552 toward the mounting plate 210. Air volume of air sucked in by suction fan 515 and blower fan 5
The air volume of the air blown from 23 is determined based on the size of the document placed on the placing plate 210 and the document amount.

The size of the document is detected by a size detection sensor. The document amount is detected by a document height sensor. The document height sensor is included in a document pressing mechanism 310 provided in the moving unit 300. The document height sensor detects the amount of the document placed on the placing plate 210 based on the displacement of the pressing bar 311 that is displaced by the pressing bar 311 pressing the rear end of the document.

FIG. 4 is a plan view in which the vicinity of the center of the mounting plate 210 is cut away for explaining the size detection sensor. The size detection sensor 252 is for detecting the size of the document based on a combination of on / off of the transmission type photoelectric sensors 253 to 256 as a plurality of photoelectric conversion units attached to the back surface of the mounting plate 210. . More specifically, the size detection sensor 252 includes a photoelectric sensor 25
A shielding unit 260 for determining on / off combinations of 3 to 256 is provided. The shielding part 260 is integrally attached to the lower part 261 of the positioning plate 250, and is for shielding between the light emitting element and the light receiving element of each of the photoelectric sensors 253 to 256.

When a document is placed on the placing plate 210, the positioning plate 250 is slid along the left edge of the document, as indicated by a two-dot chain line. That is, the sliding amount of the positioning plate 250 corresponds to the document size. On the other hand, the shielding portion 260 also slides in conjunction with the sliding of the positioning plate 250. As a result, the shielding unit 26
The sliding amount of 0 matches the sliding amount of the positioning plate 250. Therefore, the slide amount of the shielding unit 260 also corresponds to the document size.

Each of the photoelectric sensors 253 to 256 is
Reference numeral 60 is attached at a position where the reference numeral 60 is sequentially turned off every time the slide is performed by a slide amount corresponding to the document size. That is, when the shielding section 260 is slid according to the A3 or B4 size document, the positioning plate 25
Only the photoelectric sensor 253 closest to 0 is turned off.
Similarly, for a folio size document, positioning plate 2
The two photoelectric sensors 253 and 254 on the side close to 50 are turned off.

In the case of an A4 size document, the photoelectric sensor 253 closest to the positioning plate 250 is turned on, and the other two photoelectric sensors 254 and 255 are turned off. At this time, the photoelectric sensor 256 remains on. For a B5 size document, the positioning plate 250
The two photoelectric sensors 255 and 254 on the side closer to are switched on and the other two photoelectric sensors 255 and 256 are turned on.
Is turned off.

As described above, each of the photoelectric sensors 253 to 256
The combination of the ON / OFF signals output from the corresponding to the original size. By the way, since the positioning plate 250 is manually slid, the slide amount may be different even for documents of the same size. Therefore, the shielding part 2
The document size may be erroneously detected without the slide 60 sliding at an accurate slide amount according to the document size.

Therefore, the size detection sensor 252 is provided with a click mechanism 257 in order to keep the slide amount for a document of the same size constant. In this embodiment, the click mechanism 257 and the rail 251 correspond to a slide unit. The click mechanism 257 includes a positioning arm 265 integrally attached to the base 261 of the positioning plate 250, and a reference arm 232 integrally attached to the base 231 of the reference plate 230.

Positioning arm 265 and reference arm 2
Numerals 32 extend in mutually opposite directions, and are provided so as to be close to each other. Therefore, when the positioning plate 250 is slid, the positioning arm 2
65 slides so as to contact the reference arm 232. The reference arm 232 is provided with a click portion 233 that can be elastically deformed along the elastic direction P6. on the other hand,
A plurality of recesses 266 to 269 are formed in the reference arm 265 so as to face the click portion 233. Each of the concave portions 266 to 269 is formed at a position where the click portion 233 is engaged when the positioning plate 250 is slid from the initial position as shown in the drawing by an accurate slide amount corresponding to each document size. I have.

For example, when the positioning plate 250 is slid from the initial position as shown in the figure by an accurate sliding amount corresponding to the A3 size, the click portion 233 engages with the concave portion 266. Also, the positioning plate 2 is moved from the initial position as shown in the figure.
When the slider 50 is slid by an accurate sliding amount corresponding to the B5 size, the click portion 233 is engaged with the concave portion 269.

When the click portion 233 engages with any of the concave portions 266 to 269, the positioning plate 250 stops once. Therefore, the user can use the positioning plate 25
It is possible to know the slide amount corresponding to the original size of 0 exactly. Therefore, click 23 of positioning plate 250
With reference to 2, the positioning plate 250 can be slid by a slide amount that accurately corresponds to the document size.

FIG. 5 is a block diagram showing an electrical configuration related to the original setting operation of the RDH 100. RDH1
00, the CPU 5 for the main body provided in the copier main body 50
The document setting operation is performed in response to the document transfer start signal given from the second document transfer operation. The RDH 100 includes an RDH CPU 101 functioning as a control center of the RDH 100. The RDH CPU 101 is connected to the size detection sensor 252, the document height sensor 312, and the memory 102.

The memory 102 stores an original size and a set air volume corresponding to the original amount. The set air volume is
It corresponds to the amount of air blown out from the blower fan 553 and the amount of air sucked in by the suction fan 515, and is set to be larger as the document size is larger or the document amount is larger. Also, RD
The H CPU 101 is connected to the main CPU 52. The output of a print key 53 for instructing the start of copying is given to the main body CPU 52. When the print key 53 is pressed, the main body CPU 52 gives a document transfer start signal to the RDH CPU 101. The RDH CPU 101 executes a document setting process in response to a document transfer start signal.

More specifically, the RDH CPU 101
Drives a unit motor M1 and a belt motor M2 when a document transfer start signal is given. As a result, the moving unit 300 starts to move in the moving direction P1 (see FIG. 1), and the roller 513 moves in the rotational direction P4.
(See FIG. 2), and the pull-in belt 571 wound around the roller 513 starts rotating along the rotation direction P2 (see FIG. 1). At this time, CP for RDH
U <b> 101 controls the rotation speeds of the belt motor M <b> 2 and the unit motor M <b> 1 such that the peripheral speed v <b> 1 of the pull-in belt 571 is faster than the moving speed v <b> 2 of the moving unit 300.

The RDH CPU 101 refers to the outputs of the size detection sensor 252 and the document height sensor 312 to obtain the size and the amount of the document placed on the placing plate 210. Next, the set air volume is acquired by referring to the memory 102 based on the acquired document size and document amount. Further, the RDH CPU 101 sets a predetermined full drive time Δ after the print key 53 is pressed.
After the blower fan motor M4 and the suction fan motor M3 are fully driven for t, the blower fan motor M4 and the suction fan motor M3 are driven according to the obtained set air volume. As a result, the blower fan 553 and the suction fan 515 rotate according to the set airflow after full rotation. As a result, the air flow rate rises rapidly with the passage of time and then stabilizes at the set air flow rate.

As described above, the motors M4 and M3 are driven for a full drive time Δt after the print key 53 is pressed.
Is fully driven, the unstable state when the fan starts up can be quickly eliminated, and the air flow can be stabilized at the set air flow. FIG. 6 is a flowchart for explaining the document setting operation. A plurality of originals 201 are placed on the mounting plate 210
When the print key 53 is pressed in the state of being placed on the printer (FIG. 6A), the moving unit 300 moves in the moving direction P1. As a result, the rear end of the original 201 is moved by the moving unit 300 in the original transport direction P4.
It is pushed along and transported. Also, the pull-in belt 517
Rotates along the rotation direction P2. As a result, manuscript 20
The lowermost document 202 of the document 1 is pulled in by the pull-in belt 517 (FIG. 6B).

Further, the blower fan 553 and the suction fan 515 are fully rotated over the full drive time Δt. As a result, air is blown out from the blowing port 552.
The air volume increases rapidly with time and quickly stabilizes at the set air volume. Further, air is sucked into the suction duct 511. Also in this case, the air volume increases rapidly with time, and quickly stabilizes to the set air volume.
As a result, the lowermost document 202 is sucked by the pull-in belt 517 with a sufficient suction force.

At the time of document setting, as described above, the peripheral speed v1 of the pull-in belt 571 is higher than that of the moving unit 3.
Since the document is controlled so as to be faster than the moving speed v2 of 00, the lowermost document 202 is drawn in the document transport direction P4 at a higher speed than the other documents 203 stacked thereon. . As a result, the lowermost document 202 can be surely placed first (FIG. 6C).

When the document 201 is conveyed to the vicinity of the reference position 213 in such a state, the air blown from the blower port 552 is blown to the leading end of the document 201. At this time, since the lowermost original 202 of the original 201 is at the top, the air enters between the lowermost original 202 and the upper original 203 very easily. In addition, at this time, the amount of air blown out from the blowing port 552 is
It is stable at the set airflow according to the document size and the document amount. As a result, the upper document 203 is reliably levitated with a sufficient floating force (FIG. 6D). As a result, the lower original 2
02 is in a separated state.

Further, since the placing plate 210 is inclined so as to become lower toward the upstream side in the document transfer direction P4, the upper document 203 floating by the air is shifted to the upstream side in the document transfer direction P4 and its rear end. The unit contacts the mobile unit 300. This prevents the upper document 203 from being separated. Then, the leading end of the document 201 is moved to the reference position 21.
When the number reaches 3, the document 201 is set at the supply position 212 (see FIG. 3). Thus, the document setting is completed.

As described above, since the lowermost document 202 is set in a separated state, only the document 202 is sent out to the transport path 402. Thereafter, the second original from the bottom is attracted to the pull-in belt 517. As a result, air blown out from the air blowing port 522 enters between the sucked document and the document stacked thereon. As a result, the lowermost document among the remaining documents can be separated.

By repeating such an operation,
A plurality of set originals can be separated one by one. After the document is set at the supply position 212 in this manner, the document is fed onto the contact glass 51 by the document supply unit 400 and the transport belt unit 600.

FIG. 7 is a diagram for explaining the operation of conveying a document. The original 201 on the mounting plate 210 is
0 are set along the main guide surface 245 and the sub guide surface 247 of the positioning plate 250. When the transport operation starts, the lowermost document 202 of the documents 201 is transported on the transport path and set on the contact glass 51. At this time, the document 202 is set along a reference position 246 set in the width direction P8 on the contact glass 51 (hereinafter, referred to as “width reference position”). When the original 202 is in such a state, the contact glass 5
When the original is set on the original 1, the original image is copied onto a sheet without deviation.

Here, the original 202 is set along the width reference position 246 because the main guide surface 245 and the width reference position 246 are on the same line as shown in FIG. . This is the case in normal cases. However, during setup and maintenance, RDH1
When 00 is mounted on the copying machine main body 50, the main guide surface 245 may be shifted from the width reference position 246 as shown in FIG. In such a case, the document 202 is set at a position shifted from the width reference position 246. As a result, the original image is formed on the paper with a shift.

Therefore, in this embodiment, the reference plate 230
Is movable, and the main guide surface 245 is at the width reference position 2
When it deviates from 46, the main guide surface 245 can be easily adjusted to the width reference position 246. Whether or not the main guide surface 245 is deviated from the width reference position 246 can be determined by looking at the copy obtained by actually executing the copy operation.

FIG. 8 is a diagram for explaining a mounting state of the reference plate 230 and the mounting plate 210. The reference plate 230 is
It includes a main body 235 disposed above the mounting plate 210 and a base 261 disposed below the mounting plate 210.
The mounting plate 210 is provided between the main body 235 and the base 261.
The main body 235, the mounting plate 210 and the base 261 are fastened to each other with screws 236. The reference plate 230 is attached to the mounting plate 210 in such a state.

FIG. 9 is an exploded perspective view for more specifically explaining the mounting state of the reference plate 230 and the mounting plate 210. The main body 235 can be fitted to the mounting plate 210 via a mounting portion 238 having a screw hole 237 formed therein. A long hole 220 is formed in a portion corresponding to the screw hole 237 of the mounting plate 210 along the width direction P8. The long hole 220 is provided with the reference plate 23 as described later.
Screw 236 required to shift 0 along the width direction P8
To provide a moving space. The reference arm 232 is integrally attached to the base 261 along the width direction P8. A screw hole 239 is formed in a portion corresponding to the long hole 220 of the base portion 261.

When the main body 235, the mounting plate 210, and the base 261 are fastened to each other with screws 236,
When the screw 236 is loosened to the extent that it does not come off the base 261, the screw 236 is
Can be moved along the elongated hole 220 in a state in which is temporarily fastened. As a result, the main body 235 and the base 2
61 can be offset along slot 220 via screw 236.

As described above, the screw 236 is loosened and the reference plate 2
Since the position of the RDH 100 can be shifted, the position adjustment can be performed very easily as compared with the case where the position adjustment is performed by moving the RDH 100 itself. Moreover, the reference plate 2
Since 30 can be shifted along the long hole 223 formed continuously, fine adjustment can be easily performed. When the reference plate 230 is shifted, the length between the reference plate 230 and the positioning plate 250 changes. Therefore, the amount of sliding when the positioning plate 250 is slid according to the size of the document differs before and after the reference plate 230 is shifted.

On the other hand, when the reference plate 230 is shifted along the width direction P8, the reference arm 232 is also shifted as described above. More specifically, when the reference plate 230 is shifted from the state shown in FIG. 10A to the state shown in FIG. 10B, the reference arm 232 also shifts in accordance with the shift. As a result, the click portion 233 provided on the reference arm 232 is similarly shifted. Therefore, the position to be clicked when sliding the positioning plate 250 according to the document size is the same between the reference plate 230 and the positioning plate 250 before and after the reference plate 230 is shifted.

That is, in FIG. 10A, when the positioning plate 250 is slid so as to fit the original having a length of 11 in the width direction, the concave portion 267 is engaged with the click portion 233. On the other hand, when the reference plate 230 is shifted away from the reference plate 250 as shown in FIG.
50 needs to be slid longer than in FIG. 10 (a). Therefore, the position of the click portion 233 is
If it is the same as in the case of (a), it is not the concave portion 267 that engages with the click portion 233. However, the click part 233
Are shifted in conjunction with the shift of the reference plate 230, and the click portion 233 has a concave portion 267 as in the case of FIG.
Will be engaged.

As described above, even when the reference plate 230 is shifted, the positioning plate 250 can be slid accurately in accordance with the size of the document. Since the photoelectric sensors 235 to 256, which are a part of the size detection sensor 252 for detecting the document size, are attached to the back surface of the mounting plate 210, even after the document reference line 246 is displaced, It remains fixed in position. On the other hand, when the document reference line 246 is shifted, the length between the reference plate 230 and the positioning plate 250 is the same as before the displacement, but increases or decreases compared to before the displacement of the positioning plate 250 is displaced. As a result, the photoelectric sensor 2 corresponding to the document size
It is expected that 53-256 on / off combinations will change.

However, in this embodiment, the reference plate 230
Is not so long, and the positional relationship between the photoelectric sensors 253 to 256 is such that the permissible length can be sufficiently absorbed. Therefore, even after the reference plate 230 is shifted, the photoelectric sensors 253 to
The 256 on / off combinations do not change as compared to before shifting. Therefore, even when the reference plate 230 is shifted, the document size can be accurately detected.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in the above embodiment, the case where the present invention is applied to the air-feed type RDH 100 is described as an example. However, the present invention is also applied to an RDH of a type in which a document is separated by a separation roller, for example. be able to. Also, the present invention provides an ADF that automatically supplies not only RDH but also a document to a copy position and automatically discharges the document after the copy operation to a discharge position such as a discharge tray instead of the original position. Can also be applied. In short, the present invention can be applied to any apparatus that sets an original along a main guide surface and supplies the set original to a copy position.

In the above embodiment, the case where the present invention is applied to the RDH 100 mounted on a copying machine has been described as an example. However, the present invention is mounted on another image forming apparatus such as a facsimile apparatus. The present invention can be suitably applied to RDH and ADF. In addition, it is possible to make various design changes within the scope described in the claims.

[0063]

As described above, according to the present invention, when the length between the main guide surface and the sub guide surface becomes a predetermined interval according to the document size, the engaging portion and the engaged portion are engaged. Therefore, the sub guide surface member can be slid accurately in accordance with the document size. Further, since the position of the main guide surface member can be shifted in a direction crossing the document conveying direction, even if the main guide surface is shifted, the position can be easily adjusted. Moreover, fine adjustment can be easily performed because the main guide surface member is merely shifted.

Further, when the main guide surface member is displaced, the engaging arm fixed to the main guide surface member is similarly displaced. Therefore, even if the main guide surface member is displaced, the main guide surface and the sub guide surface are displaced. When the length between them becomes a predetermined interval according to the document size, the engaging portion and the engaged portion are engaged. Therefore, the length between the main guide surface member and the sub guide surface member can always be kept constant for the same document size.

According to the fourth aspect of the present invention, the switching means is turned on / off in a different combination each time the projection engages with any of the recesses. Therefore, based on the output of the switching means, the document size is reduced. Can be detected.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an internal configuration of an RDH to which an embodiment of the present invention is applied.

FIG. 2 is a plan view schematically showing a configuration centering on a mounting plate.

FIG. 3 is a diagram for explaining an initial setting position and a supply position.

FIG. 4 is a plan view in which the vicinity of the center of the mounting plate is cut away for explaining the size detection sensor.

FIG. 5 is a block diagram showing an electrical configuration of the RDH.

FIG. 6 is a flowchart for explaining a document setting operation.

FIG. 7 is a diagram for explaining a document conveying operation.

FIG. 8 is a diagram for explaining a mounting state of the reference plate to the mounting plate.

FIG. 9 is an exploded perspective view for further specifically explaining a mounting state of the reference plate to the mounting plate.

FIG. 10 is a plan view in which the vicinity of the center of the mounting plate is cut out to explain a state before and after shifting the reference plate.

[Explanation of symbols]

 100 RDH 200 Document placement part 210 Placement plate 223 Guide hole 230 Reference plate 232 Reference arm 233 Click part 239 Screw 245 Main guide surface 246 Width reference position 247 Secondary guide surface 250 Positioning plate 257 Click mechanism 265 Positioning arm 266-269 Recess P8 width direction

Claims (4)

[Claims] An original placing plate, a transporting means for transporting the original placed on the original placing plate in a predetermined original transporting direction, and provided on the original placing plate and extending in the original transporting direction. A main guide surface member having a main guide surface along one side of the original to be placed, and a sub guide surface provided on the original placing plate and having a sub guide surface provided at intervals in parallel with the main guide surface. A guide surface member, and a slide means capable of sliding the sub guide surface member in a direction crossing the document conveying direction so that the distance between the main guide surface and the sub guide surface can be changed according to the document size. The sliding means has a pair of engagement arms extending between the main guide surface member and the sub guide surface member, and one end of one of the pair of engagement arms is fixed to the main guide surface member. And the other engagement arm is Are fixed to the auxiliary guide surface member, and one of the one engagement arm and the other engagement arm is provided with one engagement portion, and the other is provided in the length direction of the engagement arm. A plurality of engaged portions are provided at predetermined intervals, and when the engaging portion and any of the engaged portions are engaged, the main guide surface and the sub guide surface correspond to the document size. An automatic document feeder, wherein the document is separated by a predetermined interval. 2. The automatic document feeder according to claim 1, wherein the position of the main guide surface member can be shifted in a direction crossing the document feed direction. 3. One of the pair of engagement arms is fixed to the main guide surface member and has one projection, and the other engagement arm is fixed to the sub guide surface member. 3. The automatic document feeder according to claim 1, further comprising a plurality of recesses formed at a predetermined interval in a length direction of the engagement arm. . 4. The apparatus further includes a plurality of switching means, and the other engagement arm further includes an operation member for turning on / off the switching means in a different combination each time the projection engages with any of the recesses. 4. The automatic document feeder according to claim 3, wherein