JP2009044449A - Automatic document feeder, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic document feeder which is provided with excellent stacking property, and to provide an image forming apparatus employing the same. <P>SOLUTION: In the automatic document feeder which separately feeds documents one by one from a loaded document bundle 1, when a quantity of documents are simultaneously processed, ejection conditions from the first document to the final document become considerably different in the document bundle 1 and stacking property of the ejected document bundle is made worse. Therefore, a rising distance L of a movable document table 3 is calculated from the total number of pulses required for rising drive control of the movable document table 3, an estimated height of ejected documents 1a on an ejection tray 29a that is made movable by being vertically turned by a motor or the like, is derived, ejection speed control is performed, and deceleration processing for decreasing the amount of ejected paper is carried out. When removal of the ejected documents 1a is confirmed by a left paper sensor 29b provided in the ejection tray 29a, the ejection tray 29a is returned to a home position at which the amount of ejected paper is zero, and the estimated height of the ejected documents 1a is reset, thereby stacking documents again from zero. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an automatic document feeder (hereinafter referred to as ADF) used in an image forming apparatus such as a copying machine, a printer, and a facsimile machine, and an image forming apparatus using the same.

  Regarding ADF, it is well known that speed control at the time of document discharge often becomes a problem. However, in the conventional invention related to ADF, for example, as shown in Patent Document 1, it also includes an effect of reducing paper stacking defects. However, it mainly considers the influence of printing, and changes the conveyance control according to image formation information on the sheet (such as toner fixing state strength and friction coefficient reduction). Regarding the stackability when processing a large amount of documents, the inventors of the present application are not aware of, for example, considering the vertical movement of the sheet discharge tray and the bottom plate of the sheet feed tray, the angle changing mechanism, and the control.

JP 2004-85982 A

  That is, ADFs in recent readers tend to increase the allowable number of originals for the purpose of processing a large amount of originals (more generally, sheet materials) at once. Here, since an increase in the number of stacked sheets leads to an increase in the number of discharged documents, the capacity of the discharge tray must also be increased. However, if the height (depth) of the paper output tray that stores the discharged originals is increased and a large number of originals are actually processed at one time, the discharge conditions from the first to the last sheet of the original bundle, The height until the sheet falls is greatly different, and the stack of discharged originals is less likely to be uniform than before.

  In addition, the paper discharge tray generally increases the stackability of documents, that is, the degree to which the discharged bundles are uniformly aligned. However, since the influence of curling or deflection of the discharged document increases as the number of sheets increases, the effect of this inclination can be reduced accordingly. Also, since the document that has flown downstream is less likely to return due to the influence of static electricity with the stack of discharged documents already stacked, it is necessary to reduce the discharge speed from this surface (always slow down) Because of this, productivity and the number of documents processed per unit time deteriorate, so from this aspect we want to discharge as fast as possible.Therefore, the speed control in question here needs to be decelerated just before discharging, but simply after reading is complete. Will not necessarily slow down).

  Thus, when processing a large amount of originals, the stackability of the discharged original bundle deteriorates. Therefore, an automatic document feeder capable of obtaining a good stacking property is desired.

  Depending on the installation conditions of the ADF, the paper discharge tray itself may be movable. When the number of paper discharges is small, it is higher than the paper discharge port (when the angle is controlled, it seems to rise horizontally). There is also a mechanism in which the sheet discharge conditions can be adjusted to some extent within the movable range by lowering (lowering horizontally) as the number of images increases. This condition also affects stackability. In addition, the status of the paper discharge tray may change due to the remaining amount of the previous use or the user partially extracting the processed portion during the current processing, and may not be confirmed by the document information on the paper feeding side. In these cases, it is naturally desirable that good stackability can be obtained.

  Also, the size of the original varies, and even though it is controlly equivalent, large paper tends to fold and fall from the point during discharge, while small paper tends to jump downstream (toward the end) of the paper output tray. The size difference between the two causes a variation in stack status. Further, in addition to the size, the paper thickness can be considered as a difference in the paper type of the document. Actually, it is easier to use thin paper than thick paper, so the leading edge of the paper may be bent sharply before the entire paper exits from the paper outlet, and the rear edge may rest on the wall on the paper outlet (rear) It tends to be the end of the edge. In these cases, it is naturally desirable that good stackability can be obtained.

  Furthermore, in the ADF, the remaining capacity of the paper discharge tray and the addition of originals on the paper feed tray side may be taken into consideration, which may eventually exceed the capacity of the paper discharge tray. If it is an environment, there is still a great concern. In this case, the document may be damaged such as bending before stacking. In such a case, it is desirable to issue a warning to the user, but conventionally no such countermeasure has been taken.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic document feeder that solves the conventional problems and an image forming apparatus using the automatic document feeder. Hereinafter, only the case where the present invention is applied to the ADF will be described, but the present invention can also be applied to a paper conveying apparatus and a sheet conveying apparatus.

  According to the first aspect of the automatic document feeder of the present invention, in order to achieve the above object, an automatic document feeder that separates and feeds a bundle of documents stacked on the bottom plate of the sheet feed tray. In the apparatus, the thickness information or height information of the document bundle on the bottom plate, the vertical movement information of the discharge tray for discharging the document after conveyance, or the angle control made by the discharge tray with respect to the automatic document feeder main body It has information detection means for detecting at least one of the information as information, and changes the speed control at the time of discharging the document to the paper discharge tray according to the change amount of any of the information detected by the information detection means It is characterized by doing.

  According to a second aspect of the present invention, in the automatic document feeder according to the first aspect, the information detecting means detects the thickness or height of the original bundle on the bottom plate as the information, and the information detecting means The height of the original stacked on the discharge tray is estimated from the amount of change in the thickness or height of the original bundle detected on the bottom plate, and the speed control when discharging the original is decelerated according to the estimated value. It is characterized by being executed as a process.

  According to a third aspect of the present invention, in the automatic document feeder according to the first aspect, the information detection means controls the vertical movement of the paper discharge tray or the angle formed by the paper discharge tray with respect to the main body of the automatic document feeder. The speed control at the time of discharging the document is executed as a deceleration process in accordance with the vertical movement of the discharge tray or the angle control information.

  According to a fourth aspect of the present invention, in the automatic document feeder of the second aspect, the speed control at the time of document discharge is executed in consideration of the vertical movement of the discharge tray or angle control information.

  According to a fifth aspect of the present invention, in the automatic document feeder of the third aspect, the speed control at the time of document ejection is executed in consideration of the thickness or height of the document bundle on the sheet ejection tray. To do.

  According to a sixth aspect of the present invention, in the automatic document feeder according to any one of the first to fifth aspects, the document has a document size detecting means for detecting the size of the document to be conveyed, and the document detected by the document size detecting means In this case, the speed control when the document is discharged is executed in consideration of the size of the document.

  According to a seventh aspect of the present invention, there is provided the automatic document feeder according to any one of the first to sixth aspects, further comprising a document thickness detecting unit that detects a thickness of the document to be conveyed. The speed control at the time of document discharge is executed in consideration of the detected thickness.

  According to an eighth aspect of the present invention, there is provided the automatic document feeder according to any one of the first to seventh aspects, wherein the thickness information or height information of the document bundle on the bottom plate of the paper feed tray is stacked on the discharge tray. Whether the amount of unprocessed document bundles on the current paper feed tray is greater than or equal to the allowable amount with respect to the current allowable amount of documents that can be discharged to the paper discharge tray, based on the estimated document height information that has been raised. And a warning means for issuing a warning when it is determined that the amount of unprocessed document bundles on the sheet feed tray is not more than the permissible amount.

  An image forming apparatus according to a ninth aspect includes the automatic document feeder according to any one of the first to eighth aspects.

  According to the automatic document feeder and the image forming apparatus using the same according to the present invention, it is possible to solve the above-described conventional problems and obtain a good stacking property.

  The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.

  The present embodiment relates to a read original processing apparatus (also referred to as ADF hereinafter) used in an apparatus that reads an original to a fixed reading device unit and reads an image while being conveyed at a predetermined speed. An example of the basic configuration, operation, and action will be described with reference to a cross-sectional view of the apparatus (FIG. 1) and a control block diagram (FIGS. 2 and 3).

  A document setting unit A for setting a document bundle to be read, a separation feeding unit B for separating and feeding documents one by one from the set document bundle, a function for performing primary abrupt alignment of a fed document, and alignment A resist portion C that pulls out and conveys the subsequent document, a turn portion D that turns the conveyed document and conveys the document surface toward the reading side (downward), and displays a surface image of the document from below the contact glass. First reading / conveying unit E for performing reading, second reading / conveying unit F for reading a back side image of a document after reading, paper discharge unit G for discharging a document whose front and back have been read out of the apparatus, and original after reading The stack unit H is configured to stack and hold, the drive units 101 to 105 that drive these transport operations, and the controller unit 100 that controls a series of operations.

  The original bundle 1 to be read is set on the original table 2 including the movable original table 3 with the original surface facing upward. Further, the width direction of the document bundle 1 is positioned in a direction perpendicular to the conveyance direction by a side guide (not shown). The document set is detected by the set filler 4 and the set sensor 5 and transmitted to the main body control unit 111 by the I / F 107. Further, the document length detection sensor 30 or 31 provided on the document table surface (a reflection type sensor or an actuator type sensor capable of detecting even one document is used) can be used to approximate the length of the document in the conveyance direction. It is determined (a sensor arrangement capable of determining at least whether the document size is vertical or horizontal is necessary).

  The movable document table 3 can be moved up and down in the directions a and b shown in the figure by a bottom plate raising motor 105. When the set filler 4 and the set sensor 5 detect that a document has been set, the bottom plate raising motor 105 is moved. The movable original table 3 is raised so that the uppermost surface of the original bundle contacts with the pickup roller 7 by normal rotation.

  The pickup roller 7 is moved by the pickup motor 101 in the c and d directions shown in the figure by a cam mechanism, and the movable table 3 is lifted and pushed by the upper surface of the original on the movable table 3 to rise in the c direction and the table lift detection sensor 8. The upper limit can be detected. When the print key is pressed from the main body operation unit 108 and a document feed signal is transmitted from the main body control unit 111 to the ADF control unit 100 via the I / F 107, the pickup roller 7 rotates by the forward rotation of the paper feed motor 102. Is rotated to pick up several (ideally one) originals on the original table 2. The rotation direction is a direction in which the uppermost document is conveyed to the sheet feeding port.

  The paper feed belt 9 is driven in the paper feed direction by the normal rotation of the paper feed motor 102, and the reverse roller 10 is driven to rotate in the reverse direction to the paper feed by the normal rotation of the paper 102 to separate the uppermost document from the document under it. Thus, only the uppermost document can be fed. More specifically, the reverse roller 10 is in contact with the paper feeding belt 9 at a predetermined pressure, and when the paper is in direct contact with the paper feeding belt 9 or through a single document, the reverse roller 10 rotates. Therefore, when two or more originals enter between the paper feeding belt 9 and the reverse roller 10, the follower force is set to be lower than the torque limiter torque. The reverse roller 10 rotates in the clockwise direction, which is the original driving direction, and pushes back an excess original, thereby preventing double feeding.

  The original separated by the action of the paper feeding belt 9 and the reverse roller 10 is further fed by the paper feeding belt 9, and the leading edge is detected by the abutting sensor 11 and further abuts against the pull-out roller 12 stopped. Thereafter, the sheet feeding motor 102 is stopped in a state in which it is fed by a predetermined amount from the detection of the abutting sensor 11 and is pressed against the pull-out roller 12 with a predetermined amount of deflection. As a result, the driving of the paper feed belt 9 is stopped. At this time, by rotating the pickup motor 101, the pickup roller is retracted from the upper surface of the document and the document is fed only by the conveying force of the paper feed belt, whereby the leading edge of the document enters the nip of the pair of upper and lower rollers of the pull-out roller 12, Tip alignment (skew correction) is performed.

  The pull-out roller 12 has the skew correction function and is a roller for conveying the skew-corrected document after separation to the intermediate roller 14 and is driven by the reverse rotation of the paper feed motor 102. At this time (at the time of reverse rotation of the paper feed motor 102), the pull-out roller 12 and the intermediate roller 14 are driven, but the pickup roller 7 and the paper feed belt 9 are not driven.

  A plurality of document width sensors 13 are arranged in the depth direction and detect the size in the width direction perpendicular to the conveyance direction of the document conveyed by the pull-out roller 12. Further, the length of the document in the conveyance direction is detected from the motor pulse by reading the leading and trailing edges of the document with the abutment sensor 11.

  When the document is transported from the resist section C to the turn section D by driving the pull-out roller 12 and the intermediate roller 14, the transport speed at the resist section C is set to be higher than the transport speed at the reading transport section E. The processing time for sending the document to the reading unit is shortened.

  When the leading edge of the document is detected by the reading entrance sensor 15, before the leading edge of the document enters the nip between the upper and lower roller pairs of the reading entrance roller 16, deceleration is started to make the document transportation speed the same as the scanning transportation speed. Then, the reading motor 103 is driven to rotate forward to drive the reading inlet roller 16, the reading outlet roller 23, and the CIS outlet roller 27. When the registration sensor 17 detects the leading edge of the document, it decelerates over a predetermined conveyance distance, temporarily stops before the reading position 20, and transmits a registration stop signal to the main body control unit 111 via the I / F 107. . Subsequently, when a reading start signal is received from the main body control unit 111, the document whose registration has been stopped is transported at an increased speed so as to rise to a predetermined transport speed before the leading end of the document reaches the reading position. At the timing when the leading edge of the document detected by the pulse count of the reading motor reaches the reading unit, a gate signal indicating an effective image area in the sub-scanning direction on the first surface is sent to the main body control unit 111 after the first reading unit Sent until the edge is removed.

  In the case of single-sided document reading, the document that has passed through the reading conveyance unit E is conveyed to the paper discharge unit G through the second reading unit. At this time, when the leading edge of the original is detected by the paper discharge sensor 24, the paper discharge motor 104 is driven to rotate forward to rotate the paper discharge roller 28 counterclockwise. In addition, the discharge motor pulse count from the detection of the leading edge of the document by the discharge sensor 24 reduces the discharge motor drive speed immediately before the trailing edge of the document comes out of the nip of the pair of upper and lower rollers of the discharge roller 28 to discharge the document. Control is performed so that the document discharged onto the tray 29 does not jump out.

  In the case of double-sided document reading, DF control is performed on the second reading unit 25 at the timing when the document leading edge reaches the second reading unit 25 by the pulse count of the reading motor after the discharge sensor 24 detects the document leading end. A gate signal indicating an effective image area in the sub-scanning direction is transmitted from the unit 100 until the trailing edge of the original passes through the reading unit. The second reading roller 26 serves as a reference white part for obtaining shading data in the second reading unit as well as suppressing floating of the original in the second reading unit.

  FIG. 4 shows an overall configuration diagram of this embodiment having sheet feeding bottom plate information (original bundle thickness) detecting means. FIG. 5 shows a control flow diagram. Elements, members, configurations, and the like that are not shown in FIGS. 4 and 5 are substantially the same as those of the apparatus of FIG. 1 and will be described with the same reference numerals even if they are not shown.

  In this embodiment, when the set sensor 5 detects that the document bundle 1 has been set, a bottom plate motor (not shown) is rotated, for example, in the clockwise direction (CW drive) (FIG. 5: Step 1), and the movable document as the bottom plate. Control of the upward drive of the table 3 is started. When the leading edge sensor 11 which is a leading edge proper position sensor detects the leading edge of the document (step 2), the sensor is turned on to stop the ascending drive of the movable document table 3 after conveying the document bundle 1 by a predetermined pulse. Then, the upper surface position of the set document stack 1 is set to an appropriate height for starting feeding (step 3). When several originals are fed from the original bundle 1 by the paper supply operation as described above, the height of the upper surface of the original bundle 1 is lowered, and the abutting sensor 11 which is the leading edge proper position sensor is turned off. Then, the raising control of the movable document table 3 is performed again so that the upper surface of the document bundle 1 is adjusted to an appropriate position (steps 2 and 3). At this time, the bottom plate motor is stopped and the ascent distance L of the movable document table 3 is calculated from the total number of pulses required for the ascending drive control of the movable document table 3 (steps 4 and 5). The estimated height of the discharged document 1a on the discharge tray 29a which is turned to be movable is derived (step 6), and the discharge speed control mode (usually a deceleration process for reducing the discharge amount) is determined. (Step 7). However, when removal of the discharged document 1a is confirmed by the remaining sheet sensor 29b provided on the discharge tray 29a, the discharge tray 29a is returned to the home position (usually the lowest position) where the discharge amount is zero. Then, the estimated height of the discharged original 1a is reset and stacked again from zero. In the figure, reference numeral 30 denotes an outer peripheral structure as an ADF main body (in FIG. 1, a part that is in series with the discharge tray 29), and 31 is a bottom plate home for detecting the home position of the movable document table 3 that is a bottom plate. It is a position sensor.

  FIG. 6 shows an overall configuration diagram of this embodiment in which the paper discharge tray 29a is movable. The discharge tray 29a can be driven to rotate in the vertical direction in the figure around the discharge tray fulcrum 29c (illustration and description of the mechanism such as the drive motor are omitted, but known and well-known ones are used. If the number of sheets is small in consideration of the ease of taking out the discharged document 29b, the position of the sheet discharge tray 29a is raised, and control is performed so as to lower as the number of sheets increases. In general, the inclination of the paper discharge tray 29a is gradually reduced from a tight state. The support position of the discharge tray 29a may be either upstream in the document discharge direction as shown in FIG. 6A or downstream as shown in FIG. 6B. . As shown in FIG. 6A and FIG. 6B, the paper discharge tray home position sensor 32 for detecting the home position of the paper discharge tray 29a is located upstream and downstream in the document discharge direction. Become position.

  That is, FIG. 6B is a diagram showing only the paper discharge section and the paper discharge tray in an example in which the movable shaft of the paper discharge tray 29a is changed. Even in this method, there is a tendency to discharge at a low speed as the number of documents increases. Although this is the same, since the inclination of the paper discharge tray 29a itself becomes tighter when the number of stacked originals is larger in this method, it is preferable that the optimum speed control is different from that in FIG.

  FIG. 7 shows a control flow diagram of this embodiment. The control shown in the drawing is the same as the control of FIG. 5 until the middle, but after the height of the discharged original is estimated in step 6, the lowering control of the discharge tray 29a is performed within the range of the discharge tray movable range ( Step 6a), the speed control is determined in consideration of the control information of the paper discharge tray 29a.

  FIGS. 8A and 8B are control flowcharts of the paper discharge tray 29a of this embodiment. In this flow, a predetermined pulse is set according to the estimated height of the discharged original 1a based on the information on the above-described bottom plate (movable original table 3).

  First, the discharge tray lowering control will be described. If the discharge tray home position sensor 32 is OFF (step 1), a motor (not shown) that moves the discharge tray 29a up and down is rotated, for example, clockwise (CW drive). (Step 2) If the discharge tray home position sensor 32 is ON (Step 3), the document is conveyed by a predetermined pulse (Step 4), and then the vertical movement of the discharge tray is driven (not shown). The motor is stopped (step 5), the discharge tray lowering flag is set, and the conveying process is finished (step 6).

  Next, the discharge tray raising control will be described. When the discharge tray lowering flag is set (step 1), if the discharge tray home position sensor 32 is ON (step 2), the discharge tray 29a is moved up and down. For example, a motor (not shown) is driven to rotate counterclockwise (CCW drive) (step 3), the discharge tray home position sensor 32 is turned off (step 4), and the original is conveyed by a predetermined pulse (step 5). Then, a motor (not shown) that drives the vertical movement of the paper discharge tray is stopped (step 6), and the paper discharge tray lowering flag that has been set is cleared and the carrying process is completed (step 7).

  FIG. 9 shows an overall configuration diagram of the third embodiment of the present invention that can detect the thickness of the original bundle on the paper discharge tray. Here, a distance measuring sensor is attached vertically downward as a stacking height detection sensor 33 to the document table 2, and the distance from the stacking height detection sensor 33 to the upper surface of the discharged document 1a is detected.

  FIGS. 10A and 10B show a method of detecting the stack height (discharged document thickness) by the stack height detection sensor 33. FIG. As shown in FIG. 10A, the stack height detection sensor 33 detects, for example, the infrared light emitted from the infrared light emitting diode 33a through the light projection lens 33b, and the discharged original surface P and the upper surface Q of the discharge tray 29a. And is received by the PSD 33d, which is a position detection element, through the light receiving lens 33c. At this time, the potential difference V is generated because the positions of the infrared light reflected from the two incident on the PSD 33d are different. In a state where the vertical movement of the discharge tray 29a is stopped, the distance L2 from the stack height detection sensor 33 to the upper surface Q of the discharge tray 29a is constant, but from the stack height detection sensor 33 to the upper surface P of the discharged document 1a. Since the distance L1 varies depending on the number of ejected documents 1, the position where the reflected light from the upper surface P of the ejected document 1 enters the PSD 33d is also shifted, and the output voltage V changes accordingly (see FIG. 10B). That is, the output voltage of the stack height detection sensor 33 also changes according to the number of originals discharged. Therefore, the distance information of the distance L1 can be acquired from the change level of the output voltage, and the deceleration control can be determined in consideration of the stack height (height or thickness of the discharged document 1).

  FIGS. 11A to 11C are control flow charts relating to stacking height detection using the stacking height detection sensor 33 and the movable discharge tray 29a. FIG. 11A shows the stacking height level determination. If the output voltage level is 4 or more (step 1), it is determined that the stacking height is too high (step 2), and the paper feed control is stopped (step 2). 3) A warning is notified (step 4). If the output voltage level is 3 or more (step 5), the lowering control of the discharge tray 29a is performed (step 6). If the output voltage level is 2 or more (step 7), the raising control of the discharge tray 29a is performed (step 8).

  FIG. 11B shows a control flow related to the stack height determination control 1 before entering the stack height level determination. First, if the paper discharge sensor 33 is OFF (step 1), it is determined whether or not the paper discharge timer exceeds a predetermined value (step 2). If the paper discharge sensor 33 is not OFF (step 1), the paper discharge timer is cleared and the control ends.

  FIG. 11C shows a control flow related to the stack height determination control 2 before entering the stack height level determination. First, when all the documents are discharged (step 1), the stacking height level is determined. If not, the discharge timer is cleared and the control is finished.

  FIG. 12 shows an overall flow chart of the control of this embodiment. In this embodiment, instead of estimating the document height, the above-described measurement by the stack height sensor 33 is performed (step 1), so that the deceleration control can be determined regardless of the information on the movable document table 3. Further, since the speed can be changed after the reading is completed at a constant speed during the reading conveyance, this flow can be executed when reading is completed, or when both sides are read when both sides are read. Unlike the control of FIG. 8, speed control is determined using actual measurement values by the stack height sensor 33 instead of estimated values (step 3), so that errors and malfunctions can be reduced.

  FIG. 13 shows a fourth embodiment having means for enabling detection of paper thickness (document thickness). As for the document size, as described above with reference to FIGS. 1 to 3, the document width can be calculated by the document width sensor 13 and the length can be calculated by motor pulse measurement using the abutment sensor 11 during conveyance. Good.

  As shown in FIG. 13A, when the document p enters the nip between the upper and lower roller pairs of the pull-out rollers 12a and 12b, the shaft 12c of the lower roller 12b moves by a distance corresponding to the thickness of the document p. . The amount of movement is detected by a displacement sensor 34 that can detect even a small amount, and the paper thickness information for each original is measured from the sensor output difference before and after the nip entry of the original p. An example of the relationship between the detection distance of the displacement sensor 34 and the output voltage is shown in FIG. However, this is just an example.

  The document size (width, length) and paper thickness measured as described above are recorded and held for each conveyed sheet, and are reflected in the speed control decision in the control flow shown in FIG.

  FIG. 14 is a control flowchart of the fourth embodiment. In this control, it is assumed that the ascent distance L of the movable document table 3 as the bottom plate is calculated from the control in FIG. An amount S1 obtained by subtracting the rising distance L from the maximum rising distance suitable for document reading is the estimated thickness (height) of the entire unprocessed document (step 1). On the other hand, the thickness (height) of the discharged document and the lowering of the discharge tray are measured by the method and control shown in FIGS. 10 to 11, and the remaining stacking capacity S2 at that time is determined from the movable range of the discharge tray 29a. Is determined (step 2). At this time, if the value S1 is larger than S2, it can be estimated that the paper discharge tray overflows, so the sign of S = S1-S2 is judged (steps 3 to 5), and a warning is given to the user when the value changes from the previous measurement ( Step 6) or a warning cancellation is transmitted (Step 7). The warning or the warning cancellation can be realized by notifying the apparatus main body of the warning or the warning cancellation via the IF 107 shown in FIG. 2 and causing the operation unit 108 to appear or disappear, for example.

Sectional drawing which shows the basic structural example of a to-be-read document processing apparatus (ADF). Control block diagram of the apparatus of FIG. Control block diagram of the apparatus of FIG. Overall configuration diagram of the present embodiment having sheet feeding bottom plate information detection means Control flow diagram of the embodiment of FIG. Overall configuration diagram of Embodiment 2 of the present invention in which the discharge tray is movable Control flow diagram of the embodiment of FIG. FIG. 6 is a control flow chart of the paper discharge tray in the embodiment of FIG. Overall configuration diagram of Embodiment 3 of the present invention capable of detecting the document bundle thickness on the paper discharge tray The figure which shows the detection method of the Example of FIG. FIG. 9 is a control flow diagram regarding stacking height detection using a stacking height detection sensor and a movable discharge tray in the embodiment of FIG. Overall flow chart of control of embodiment 3 The figure which shows Example 4 of this invention provided with the means which can detect paper thickness (thickness of an original). Control flow diagram of embodiment 4

Explanation of symbols

1: Document bundle 1a: Discharged document 3: Moveable document table 5: Set sensor 11: Abutment sensor 12a, 12b: Pull-out roller 12c: Roller shaft 13: Document width sensor 29a: Discharge tray 29b: Remaining sheet sensor 29c: Discharge tray fulcrum 30: ADF main body 31: Bottom plate home position sensor 32: Discharge tray home position sensor 33: Stack height detection sensor 33a: Infrared light emitting diode 33b: Light projecting lens 33c: Light receiving lens 33d: PSD
34: Displacement sensor p: Document L1: Distance from the stack height detection sensor to the upper surface of the discharged document P: Output document surface Q: Upper surface of the output tray

Claims (9)

  In an automatic document feeder that separates and feeds a bundle of documents stacked on the bottom plate of a sheet feed tray, the thickness information or height information of the document bundle on the bottom plate, and the finished document are discharged. Information detecting means for detecting at least one of the vertical movement information of the paper discharge tray to be performed or the angle control information formed by the paper discharge tray with respect to the automatic document feeder main body, and the information detecting means detects the information An automatic document feeder, wherein the speed control at the time of discharging a document to the discharge tray is changed in accordance with a change amount of any information.   2. The automatic document feeder according to claim 1, wherein the information detection unit detects the thickness or height of a bundle of documents on the bottom plate as the information, and the document on the bottom plate detected by the information detection unit. The height of the document stacked on the discharge tray is estimated from the amount of change in the thickness or height of the bundle, and the speed control during document discharge is executed as a deceleration process according to the estimated value. Automatic document feeder.   2. The automatic document feeder according to claim 1, wherein the information detection unit controls the vertical movement of the paper discharge tray or the angle formed by the paper discharge tray with respect to the main body of the automatic document feeder. An automatic document feeder, wherein the speed control at the time of document discharge is executed as a deceleration process in accordance with vertical movement or angle control information of a paper tray.   3. The automatic document feeder according to claim 2, wherein speed control at the time of document ejection is executed in consideration of vertical movement or angle control information of the paper ejection tray.   4. The automatic document feeder according to claim 3, wherein speed control at the time of document ejection is executed in consideration of a thickness or height of a bundle of documents on the paper ejection tray.   6. The automatic document feeder according to claim 1, further comprising document size detecting means for detecting a size of a document to be conveyed, taking into account the size of the document detected by the document size detecting means. An automatic document feeder characterized by executing speed control during discharge.   7. The automatic document feeder according to claim 1, further comprising document thickness detection means for detecting the thickness of the document to be conveyed, taking into account the thickness detected by the document thickness detection means. An automatic document feeder that performs speed control when the document is discharged.   8. The automatic document feeder according to claim 1, wherein thickness information or height information of a document bundle on the bottom plate of the paper feed tray, and estimated document height information stacked on the discharge tray, Thus, it is determined whether or not the amount of unprocessed document bundles on the current paper feed tray is greater than or equal to the allowable amount with respect to the current allowable amount of documents that can be discharged to the paper discharge tray. An automatic document feeder having warning means for issuing a warning when it is determined that the amount of unprocessed document bundles on the upper side is more than the allowable amount and is unacceptable. An image forming apparatus comprising the automatic document feeder according to claim 1.