JP7251163B2 - Determining device, conveying device, image reading device, and image forming device - Google Patents

Description

The present invention relates to a determination device, a conveying device, an image reading device, and an image forming device.

Generally, in an image reading apparatus or an image forming apparatus, it is determined whether or not multi-feeding occurs in the conveying path. The multiple feeding means that a plurality of sheet-like objects are conveyed in a state of being overlapped in the conveying path.

In the image forming apparatus according to the related art, the type of the object (for example, envelope or paper) is set based on the user's operation. The image forming apparatus is provided with an ultrasonic sensor that emits ultrasonic waves toward the object conveyed in the conveying path and outputs a signal having a level corresponding to the incident wave from the object. . Further, in the image forming apparatus, when the type of the object is set to be an envelope, the multi-feed occurs when the change over time of the signal does not satisfy a first specific condition defined for the envelope. transport of the plurality of envelopes is stopped. Further, when the type of the object is set to paper, the conveyance of the plurality of papers is stopped when the change over time of the output signal does not satisfy a second specific condition different from the first specific condition for the paper. It is stopped (see Patent Document 1, for example).

JP 2013-43732 A

However, in the image reading apparatus or the like, it is determined whether or not the multi-feeding has occurred based on specific conditions that differ depending on the type of the object. Therefore, when multiple types of objects are sequentially transported in the transport path, it is not possible to correctly determine whether or not double feeding occurs in the transport path for at least one of the multiple types of objects. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide a determination device, a transport device, and an image reading device capable of determining whether or not multiple types of objects are multi-fed even when multiple types of objects are sequentially transported in the transport path. and to provide an image forming apparatus.

A determination device according to one aspect of the present invention includes an acquisition processing unit and a determination processing unit. The acquisition processing unit acquires a signal based on an ultrasonic wave emitted to an object conveyed in a specific direction. The determination processing unit determines that a first time until the level of the signal changes from a predetermined first level threshold to a second level threshold smaller than the first level threshold is equal to or greater than a predetermined first time threshold. Determine whether or not

A conveying device according to another aspect of the present invention includes a sensor section and the determination device. The sensor unit emits an ultrasonic wave to the object and outputs the signal whose level changes according to the incident wave from the object.

An image reading device according to another aspect of the present invention includes the determining device or the conveying device.

An image forming apparatus according to another aspect of the present invention includes the determining device or the conveying device.

According to the present invention, even when a plurality of types of objects are sequentially conveyed in the conveying path, a judgment device, a conveying device, an image reading device, and an image forming apparatus capable of judging the presence or absence of multi-feeding of each kind of objects. Equipment can be provided.

FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus according to one embodiment of the present invention. FIG. 2A is a schematic diagram showing the first object when viewed from the back side and the cross-sectional shape of the first object when viewed from the width direction of the cross section along the two-dot chain line III-III. 2B is a schematic diagram showing a first object placed on the first set section shown in FIG. 1; FIG. FIG. 3 is a schematic diagram showing the second object when viewed from the surface side. FIG. 4A is a diagram showing temporal changes in signals when one second object is conveyed in the first conveying path shown in FIG. FIG. 4B is a diagram showing temporal changes in signals when two second objects are conveyed in the first direction without being shifted in the first conveying path shown in FIG. FIG. 4C is a diagram showing temporal changes in signals when two second objects are transported in the first transport path shown in FIG. 1 while being shifted in the first direction. FIG. 4D is a diagram showing temporal changes in signals when one first object is conveyed in the first conveying path shown in FIG. 1 . FIG. 5 is a diagram showing a block configuration of the image forming apparatus shown in FIG. 1. As shown in FIG. 6A is a flow chart showing the first part of the processing procedure of the control unit shown in FIG. 5; FIG. 6B is a flowchart showing a second part of the processing procedure of the control unit shown in FIG. 5; FIG. FIG. 7 is a schematic diagram showing the detailed configuration of the image reading apparatus shown in FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. It should be noted that the following embodiment is an example that embodies the present invention, and is not intended to limit the technical scope of the present invention.

In FIG. 1, arrows X1, Y1, and Z1 indicate the front-back direction, the left-right direction, and the up-down direction of the image forming apparatus 100. As shown in FIG.

The image forming apparatus 100 is a copier, printer, facsimile machine, multifunction machine, or the like. The MFP has a copy function, a print function, a facsimile function, and the like. The image forming apparatus 100 includes a main device 200 and an image reading device 300 . Note that the image forming apparatus 100 may not include the image reading device 300 .

The main unit 200 includes a first set section 22 , a first transport section 23 , a first sensor section 24 , an image forming section 25 , a first discharge section 26 and a control section (that is, determination device) 27 . In main device 200 , transport device 400 includes at least first transport section 23 , first sensor section 24 and control section 27 .

Inside the main device 200, a first transport path CP1 along which the object A1 is transported is provided. The first transport path CP1 extends from the first upstream end CP11 to the first downstream end CP12. The first upstream end CP11 and the first downstream end CP12 are specifically provided at predetermined vertical positions in the right side portion 200A and the left side portion 200B of the main unit 200, respectively.

The first set portion 22 is a manual feed tray, and extends obliquely upward to the right from a position immediately below the upstream end CP11 in the right side portion 200A. A plurality of types of objects A1 can be loaded on the first set section 22 . The multiple types of target objects A1 include a first target object A11 (see FIG. 2A) and a second target object A12 (see FIG. 3).

In FIG. 2A, arrows X2, Y2, and Z2 respectively indicate the length direction, width direction, and thickness direction of the first object A11. A frame F1 in FIG. 2A shows the first object A11 when a cross section along the two-dot chain line III-III parallel to the length direction is viewed from one side in the width direction.

The first object A11 is an unused envelope or the like, and has a body portion B11 and a flap portion B12. The trunk portion B11 has a substantially rectangular shape in plan view from the thickness direction. The trunk portion B11 further has a bag-like shape in which a plurality of sheets overlap in the thickness direction. Specifically, one side of the body portion B11 in the longitudinal direction is opened to form a filling port B13 as shown in the frame F1. Further, the other side of the trunk portion B11 in the longitudinal direction is closed as shown in the frame F1 to form a closed portion B14. The flap portion B12 extends from the other side of the trunk portion B11 and is folded back to close the enclosure opening B13. As shown in FIG. 2B, the first object A11 is placed on the first set portion 22 such that the closing portion B14 is along the upstream end CP11.

In FIG. 3, arrows X3, Y3 and Z3 indicate the length direction, width direction and thickness direction of the second object A12, respectively. The second object A12 is an unused sheet of paper, an OHP sheet, or the like, and is a sheet having a constant thickness over the entire length and width directions. Note that the image forming apparatus 100 can form images on the second target A12 having a plurality of thicknesses different from each other.

In FIG. 1, the first transport unit 23 includes a pickup roller and a pair of transport rollers, feeds the object A1 from the first upstream end CP11 to the first transport path CP1, and then moves the object A1 within the first transport path CP1. is conveyed in the first direction D11 at a predetermined speed V1. The first direction D11 is the downstream direction of the first transport path CP1, and is a first example of a specific direction in the present invention. Also, the speed V1 is a first example of a specific speed in the present invention.

The first sensor section 24 is a first example of the sensor section in the present invention, and is a transmissive ultrasonic sensor. The first sensor unit 24 includes a transmitter 241 and a receiver 242, as shown in FIG. 2B.

The transmitter 241 can emit an ultrasonic wave (hereinafter referred to as a measurement wave) toward a predetermined detection position DP1 immediately downstream of the first transport section 23 on the first transport path CP1. The amplitude level of the measurement wave is predetermined.

The receiver 242 is arranged at a position facing the transmitter 241 across the detection position DP1. The receiver 242 outputs to the controller 27 a signal ES1 based on the measurement wave emitted toward the object A1 passing through the detection position DP1. Specifically, the signal ES1 has a level (that is, a voltage value) that changes according to the ultrasonic wave (hereinafter referred to as incident wave) incident on the receiving section 242 based on the measurement wave. The level of the signal ES1 relates to the total thickness of the objects A1 passing through the detection position DP1, more specifically, the type and number of the objects A1.

The type and number of objects A1 are (1) when one second object A12 passes through the detection position DP1 (see FIG. 4A), and (2) when two or more second objects A12 are the first When passing the detection position DP1 aligned in the direction D11 (see FIG. 4B), (3) the two or more second objects A12 pass the detection position DP1 while being shifted in the first direction D11. It can be roughly classified into the case (see FIG. 4C) and (4) the case (see FIG. 4D) in which one sheet of the first target A11 passes over the detection position DP1.

In the case of (1), the signal ES1 exhibits the first level L11 in the first time interval T11 in which the single second object A12 does not pass the detection position DP1, as shown in FIG. 4A. Note that the signal ES1 is the first target object A12 (see FIGS. 4B and 4C) and one first target object A11 (see FIG. 4D) that have not passed the detection position DP1. During time interval T11, signal ES1 exhibits a first level L11. In the case of (1), the signal ES1 exhibits a second level L12 that is lower than the first level L11 in a second time interval T12 in which one second object A12 passes through the detection position DP1.

In case (2), the signal ES1 exhibits a level lower than the second level L12 in the third time interval T13, as shown in FIG. 4B. Note that FIG. 4B illustrates a case where the signal ES1 exhibits the third level L13 in the third time interval T13. In the third time interval T13, the two second objects A12 pass through the detection position DP1 while overlapping each other. Even when three or more second objects A12 pass over the detection position DP1, the level of the signal ES1 changes over time as in FIG. 4B.

In case (3), the signal ES1 exhibits a level lower than the second level L12 (for example, the third level L13) in the third time interval T13, and the second level L13 in the fourth time interval T14, as shown in FIG. 4C. Level L12 is shown. In the fourth time interval T14, only one of the two second objects A12 passes through the detection position DP1.

In the case of (4), the trunk portion B11 of the first object A11 is similar to the case of (2) in that a plurality of sheets are overlapped, but the plurality of sheets are connected by the closing portion B14 or the like. This is different from the case (2) in one point. Therefore, in the fifth time interval T15 from when the torso B11 starts passing through the detection position DP1 until the specific time elapses, the level of the signal ES1 decreases with time and then reaches the third level L13. The reason is as follows.

The vibration generated by the measurement wave hitting the first region R11 is not greatly attenuated, as indicated by the arrow E1 in the frame F2 of FIG. 4D. propagates to the second region R12. The first region R11 is a region near the closing portion B14 among the plurality of sheets passing through the transmitting portion 241 side. The second region R12 is a region near the closing portion B14 in the sheet passing through the receiving portion 242 side. The vibration propagated to the second region R12 propagates to the receiver 242 via air. In addition, since the first object A11 is transported in the first direction D11, the propagation distance from the first region R11 to the closing portion B14 increases over time. Therefore, the vibration propagated to the second region R12 decreases over time. From the above, the level of the signal ES1 reaches the third level L13 after decreasing with the passage of time, as shown in FIG. 4D. The length of the fifth time interval T15 is determined by the material and thickness of the first object A11, the speed V1, and the distance from the bottom B14 in the direction opposite to the first direction D11.

In the case of (4), the signal ES1 exhibits the third level L13 in the sixth time interval T16 and the second level L12 in the seventh time interval T17, as shown in FIG. 4D. A sixth time interval T16 is a time interval after the fifth time interval T15 has elapsed in the time interval in which the torso B11 passes through the detection position DP1. In the seventh time interval T17, the flap portion B12 (see FIG. 2A) of the first object A11 passes through the detection position DP1.

In FIG. 1, the image forming unit 25 conveys an image based on image data transmitted from the control unit 27 within the conveying path CP1 at a position downstream of the first sensor unit 24 on the first conveying path CP1. formed on the target object A1. The image forming section 25 discharges the object A1 on which the image is formed onto a first discharge section 26 such as a paper discharge tray. Note that the image forming unit 25 forms the image by an electrophotographic method or an inkjet method.

The control unit 27 is also the determination device 27 . The control unit 27 includes a processor, a program storage unit such as ROM, and a work area such as RAM. The processor executes a program pre-stored in the program storage unit using the work area. Thereby, the control unit 27 controls each unit of the image forming apparatus 100 in an integrated manner. Note that the control unit 27 may be an electronic circuit such as an ASIC (Application Specific Integrated Circuit) or a DSP (Digital Signal Processor). Note that when the image forming apparatus 100 includes the image reading device 300 , the control section 27 may be provided in the image reading device 300 .

In the image forming apparatus according to the related art, it is determined whether or not multi-feeding occurs based on different conditions for each type of object conveyed in the conveying path. Therefore, when multiple types of objects are sequentially transported in the transport path, it is possible to correctly determine whether or not the multi-feed occurs in the transport path for at least one of the multiple types of objects. Can not. On the other hand, according to the image forming apparatus 100, even when a plurality of types of target objects are sequentially transported in the transport path, multi-feed determination can be made for each type of target object.

In the image forming apparatus 100, as shown in FIG. 5, the control section 27 includes an acquisition processing section 27A, a determination processing section 27B, a timing processing section 27C, a detection processing section 27D, and a transport control section 27E. The control unit 27 functions as an acquisition processing unit 27A, a determination processing unit 27B, a timing processing unit 27C, a detection processing unit 27D, and a transport control unit 27E by the processor executing the program.

The acquisition processing unit 27A acquires the signal ES1 from the first sensor unit 24. FIG.

The determination processing unit 27B determines that the first time ET1 (see FIG. 6A) until the level of the signal ES1 changes from the first level threshold LT1 (see FIGS. 4A to 4D) to the second level threshold LT2 is the first time. It is determined whether or not it is equal to or greater than a threshold TT1 (see FIG. 4D).

The first level threshold LT1, the second level threshold LT2, and the first time threshold TT1 are determined in advance through experiments or simulations during the design and development stage of the image forming apparatus 100, and are described in the program.

The first level threshold LT1 and the second level threshold LT2 are determined based on the thickness of the object A1 in the second direction D12 intersecting the first direction D11. The second direction D12 is a first example of the intersecting direction of the present invention, specifically, the direction along the vertical direction. Specifically, the first level threshold LT1 has a value closer to the second level L12 between the second level L12 and the third level L13, as shown in FIG. 4B. The second level threshold LT2 is smaller than the first level threshold LT1, and specifically has a value closer to the third level L13 between the second level L12 and the third level L13. More specifically, the first level threshold LT1 is set so that the level of the signal ES1 exceeds the second level L12 when one second object A12 passes through the detection position DP1, as shown in FIG. 4A. Determined. Further, as shown in FIG. 4B, the first level threshold LT1 is such that when the first object A11 or the plurality of second objects A12 pass through the detection position DP1, the signal ES1 becomes equal to or lower than the second level L12, and It is determined to be equal to or lower than the third level L13.

Also, the first time threshold TT1 shown in FIG. 4D is determined based on the speed V1 and the distance from the end of the object A1 on the first direction D11 side in the direction opposite to the first direction D11. Here, the timings at which the level of the signal ES reaches the second level L12 and the third level L13 are assumed to be the start time t0 and the end time t1 of the fifth time interval T15. The first time threshold TT1 is the time from the start time t0 of the fifth time interval T15 to the time t2 closer to the end time t1. More specifically, among the distances from the end on the first direction D11 side in the opposite direction, the distance D31 at which the level of the signal ES transitions from above the third level L13 to below the third level L13 is determined in advance by the experiment or the simulation. Desired. In this case, the first time threshold TT1 is predetermined to be equal to or less than the distance D31 divided by the speed V1.

The timing processing unit 27C measures the elapsed time from the time when the determination processing unit 27B determines that the level of the signal ES1 is equal to or lower than the first level threshold value LT1. The elapsed time is used as the first time ET1 and the second time ET2 by the determination processing section 27B.

After determining that the first time ET1 is not equal to or greater than the first time threshold TT1, the determination processing unit 27B can determine double feeding of the objects based on the level of the signal ES1 acquired by the acquisition processing unit 27A. is. Specifically, in the multifeed determination, the determination processing unit 27B determines that the second time ET2 (see FIG. 6B) during which the level of the signal ES1 is equal to or less than the first level threshold LT1 is equal to or exceeds the first time threshold TT1 (see FIG. 4D). ) is greater than or equal to a second time threshold TT2 (see FIG. 4C).

The second time threshold TT2 is predetermined based on the speed V1 and the length of the specific object A1 in the first direction D11. Specifically, the specific object A1 is the second object A12 having the shortest length in the first direction D11 among the second objects A12 on which the image forming apparatus 100 can form an image. A second time threshold TT2 is the time obtained by dividing the length of the particular object A1 by the velocity V1.

The detection processing unit 27D detects whether or not the object A1 is double-fed according to the determination result of the determination processing unit 27B. Specifically, the detection processing unit 27D detects that there is no double feeding when the determination processing unit 27B determines that the first time ET1 is equal to or greater than the first time threshold TT1. In this case, the transport controller 27E further transports the object A1 downstream in the first direction D11. The detection processing unit 27D detects that there is double feeding when the determination processing unit 27B determines that the first time ET1 is not equal to or greater than the first time threshold TT1. In this case, the transport control unit 27E can stop transporting the object A1 in the first direction D11.

Next, the processing and control of the control section 27 in the image forming apparatus 100 will be described in more detail.

First, the user loads a plurality of objects A1 on the first set section 22 (see FIG. 1). The plurality of objects A1 includes a first object A11 and a second object A12. The control unit 27 also acquires image data representing an image to be formed. Specifically, control unit 27 receives the image data from an information processing apparatus (not shown) communicably connected to image forming apparatus 100 via a network. The control unit 27 may receive the image data from the image reading device 300 when the image forming apparatus 100 includes the image reading device 300 . When the image data is received, the control unit 27 repeatedly executes the processing of FIGS. 6A to 6C for one object A1 a required number of times, and obtains images represented by the image data for the required number of objects. Form in A1. However, since the double feeding can occur on the first transport path CP1, the processing of FIGS. 6A to 6C includes double feeding detection processing.

At step S101 in FIG. 6, the control unit 27 functions as the transport control unit 27E. The transport control unit 27E controls the first transport unit 23 to start transporting the object A1 on the first set unit 22. FIG.

Next, the control unit 27 functions as the acquisition processing unit 27A in step S102 and acquires the signal ES1 from the first sensor unit 24. FIG. Next, the control section 27 functions as the determination processing section 27B in step S103. The determination processing unit 27B determines whether or not the level of the signal ES1 is equal to or lower than the first level threshold LT1 (see FIG. 4A, etc.) in order to determine whether there is a possibility of occurrence of double feeding at this time. If the level is not equal to or lower than the first level threshold LT1, the judgment processing section 27B determines that there is no occurrence of double feeding at this time, and advances the process to step S104. Proceed to step S106.

The control unit 27 functions as a detection processing unit 27D and a transport control unit 27E in step S104. The detection processing unit 27D detects that the double feeding has not occurred in the first transport path CP1. In this case, the transport control unit 27E controls the first transport unit 23 to continue transporting the object A1.

Next, in step S105, the transport control unit 27E determines whether it is time to stop the pickup roller in the first transport unit 23 or not. The stop timing is timing immediately after the rear end of the object A1 in the first direction D11 passes the pickup roller. Specifically, the transport control unit 27E determines whether or not it is the stop timing based on an output signal from an optical sensor or the like provided near the first upstream end CP11. If it is the stop timing, the transport control unit 27E stops the pickup roller, ends the processes of FIGS. 6A to 6C, and waits for the start of transport of the next object A1. If the stop timing does not come, the transport control unit 27E returns the process to step S102.

When one second object A12 is being transported within the first transport path CP1 (see FIG. 4A), a processing loop consisting of steps S102 to S105 is repeated. In this case, the image forming section 25 forms the image on the second object A12 being conveyed. After that, the second object A<b>12 with the image formed thereon is discharged onto the first discharge unit 26 .

The control unit 27 functions as the clock processing unit 27C in step S106, and starts measuring the elapsed time from the start of execution of step S106. Next, the control unit 27 functions as the acquisition processing unit 27A in step S107 and acquires the signal ES1 from the first sensor unit 24. FIG. Next, the control unit 27 functions as the determination processing unit 27B in step S108, and determines whether or not the level of the signal ES1 is equal to or lower than the second level threshold LT2 (see FIGS. 4B to 4D). It is determined whether or not double feeding has occurred on the transport path CP1. If the level is equal to or lower than the second level threshold LT2, the determination processing unit 27B determines that one first object A11 (see FIG. 4D) or a plurality of second objects A12 (see FIG. 4D) in the first transport path CP1. 4B and 4C) is conveyed, the process proceeds to step S109. If the level is not equal to or lower than the second level threshold value LT2, the determination processing unit 27B determines that not one first object A11 is being conveyed in the first conveying path CP1, but that a plurality of second objects are being conveyed. Assuming that A12 is being transported, the process proceeds to step S114 in FIG. 6B.

When returning the process to step S107, the acquisition processing unit 27A acquires the signal ES1 multiple times at time intervals. When the time interval is ΔT, ΔT is a time shorter than the first time threshold TT1. Image forming apparatus 100 is designed such that acquisition processing unit 27A acquires signal ES1 at time intervals ΔT.

The control unit 27 functions as a determination processing unit 27B and sequentially executes steps S109 and S110. The determination processing unit 27B acquires the elapsed time as the first time ET1 from the timing processing unit 27C in step S109, and determines whether the first time ET1 is equal to or greater than the first time threshold TT1 in step S110. It is determined whether or not double feeding has occurred in the first transport path CP1. If the first time ET1 is greater than or equal to the first time threshold TT1, the determination processing unit 27B proceeds to step S111. If the first time ET1 is not equal to or greater than the first time threshold TT1, the determination processing unit 27B determines that the plurality of second objects A12 are transported in the first transport path CP1 (see FIGS. 4B and 4C), Assuming that transmission has occurred, the process proceeds to step S114 in FIG. 6B.

In step S111, the control unit 27 functions as the clock processing unit 27C and finishes clocking, and then advances the process to step S112. The control unit 27 functions as the detection processing unit 27D in step S112, assumes that the object A1 being conveyed is a first object A11 (see FIG. 4D), and detects the weight within the first conveying path CP1. Detects that transmission has not occurred. The control unit 27 further functions as the transport control unit 27E in step S112, and further transports the single first object A11 downstream in the first direction D11. Step S112 is repeated until the transport control unit 27E determines in step S113 that the stop timing has come.

6A to 6C, steps S105 to S110 take a first time ET1 (see FIG. 4D) until the level of the signal ES1 changes from the first level threshold LT1 (see FIG. 4D) to the second level threshold LT2. 6A) is equal to or greater than a predetermined first time threshold TT1 (see FIG. 4D), one sheet of the first object A11 is passing through the detection position DP1, and the double feeding has occurred. The absence is detected by the detection processing unit 27D. That is, even if the user does not set the type of the object A1 (that is, the first object A11 or the second object A12), the control unit 27 controls the object A1 being conveyed within the first conveying path CP1. can be automatically identified as the first object A11. Thereafter, a processing loop composed of steps S112 and S113 is repeated. The image forming unit 25 forms the image on the first object A11 being conveyed. After that, the second object A<b>12 with the image formed thereon is discharged onto the first discharge unit 26 .

The control unit 27 functions as the determination processing unit 27B in steps S114 and S115. The determination processing unit 27B acquires the elapsed time as the second time ET2 from the clock processing unit 27C in step S114. The determination processing unit 27B determines whether or not the second time ET2 is greater than or equal to the second time threshold TT2. The determination processing unit 27B advances the process to step S116 if the second time ET2 is not equal to or greater than the second time threshold TT2, and advances the process to step S117 if the second time ET2 is equal to or greater than the second time threshold TT2.

The controller 27 functions as the transport controller 27E in step S116 and continues transporting the plurality of second objects A12 in the first transport path CP1.

The control unit 27 functions as the clock processing unit 27C in step S117, and terminates clocking. Next, the control unit 27 functions as the detection processing unit 27D in step S118, and the plurality of second objects A12 are passing through the detection position DP1 on the first transport path CP1 (see FIGS. 4B and 4C). , to detect the occurrence of the double feeding. The control unit 27 further functions as the transport control unit 27E in step S114 to stop transporting the plurality of second objects A12 in the first direction D11. Specifically, the transport control unit 27E controls the first transport unit 23 to transport the plurality of second objects A12 in the first transport path CP1 in the direction opposite to the first direction D11, and the upstream end thereof. It is discharged from the CP 11 to the first set section 22 .

6A to 6C, multiple types of target objects A1 (first target object A11 and second target object A12) are loaded on the first set unit 22, and multiple types of target objects are loaded in the first transport path CP1. It is possible to provide the determining device 27, the conveying device 400, and the image forming apparatus 100 that can determine the presence or absence of multi-feeding of each type of target A1 even when A1 is sequentially transported.

It should be noted that the control unit 27 may determine whether the level of each signal ES1 acquired at the time interval ΔT is the first level threshold LT1.

Further, when it is determined in step S110 that the first time ET1 is not equal to or greater than the first time threshold TT1, the control section 27 may execute steps S117 and S118 without executing steps S114 to S116.

In FIG. 7, the image reading device 300 is provided above the main device 200 . Note that the image reading device 300 may be a scanner or the like independent from the image forming device 100 .

The image reading device 300 includes an ADF (Automatic Document Feeder) 310, a cover 320, a contact portion 330, an image reading portion 340, and the like, and optically reads an image displayed on an object A2 to be conveyed to obtain image data. is generated and output to the control unit 27 (see FIGS. 1 and 5).

ADF 310 is a document feeder and is provided on the upper surface of main device 200 integrally with cover 320 . The ADF 310 includes a second set section 31 , a second transport section 32 , a second sensor section 33 and a second discharge section 34 . In the image forming apparatus 100, the conveying device 400 is provided in the image reading device 300 and includes at least the second conveying section 32, the second sensor section 33, and the control section 27 (see FIGS. 1 and 5).

Further, inside the ADF 310, a second transport path CP2 along which the object A2 is transported is provided. The second transport path CP2 extends from the second upstream end CP21 to the second downstream end CP22. Specifically, the second upstream end CP21 is provided at a position closer to the center in the left-right direction and closer to the upper side of the ADF 310 . The second downstream end CP22 is provided at a position below the second upstream end CP21 in the ADF 310 . The upstream portion of the second transport path CP2 extends leftward from the second upstream end CP21, and the intermediate portion curves downward between the upstream portion and the downstream portion of the second transport path CP2. The downstream portion extends obliquely upward to the right from the intermediate portion to the second downstream end CP22.

The second set portion 31 is a supply tray and is provided in the upper right portion of the image reading device 300 . A plurality of types of target objects A2 can be loaded on the second set portion 31 . The multiple types of target objects A2 include a first target object A21 and a second target object A22. The first object A21 differs from the first object A11 only in that it is a used envelope on which an address and the like are written. The second object A22 differs from the second object A12 only in that it is paper or an OHP sheet on which an image or the like is recorded. Therefore, in the following, in the first object A21 and the second object A22, the same reference numerals are given to the parts corresponding to the first object A11 and the second object A12, and the respective explanations are omitted. and refer to FIGS. 2A and 3 . As shown in FIG. 7, the first object A21 is placed on the second set portion 31 so that the closing portion B14 is along the upstream end CP21.

The second transport unit 32 includes a pickup roller and a pair of transport rollers, feeds the object A2 from the second upstream end CP21 to the second transport path CP2, and then moves the object A2 in the second transport path CP2 in the third direction. The object A2 is conveyed at a speed V2 predetermined in D21. The third direction D21 is the downstream direction of the second transport path CP2, and is a second example of a specific direction in the present invention.

The second sensor section 33 is a second example of the sensor section in the present invention, and is a transmissive ultrasonic sensor. The second sensor unit 33 includes a transmitting unit 331 and a receiving unit 332 facing each other across a predetermined detection position DP2. The detection position DP2 is a position immediately downstream of the second conveying section 32 on the second conveying path CP2. The second sensor section 33 can emit a measurement wave having a predetermined amplitude level from the transmission section 331 toward the detection position DP2. The second sensor section 33 outputs a signal ES2 based on the measurement wave from the receiving section 332 to the control section 27 . The level of the signal ES2 is related to the type and number of objects A2 passing through the detection position DP2 (see FIGS. 4A to 4D).

The second discharge section 34 is a discharge tray and is provided on the right side of the second downstream end CP22. The target object A2 discharged from the second downstream end CP22 can be loaded on the second discharge section 34 .

The contact portion 330 is a translucent plate member such as a glass plate or a resin plate. Contact portion 330 is provided on the upper surface of main device 200 near the left end. The contact portion 330 is attached to the upper surface of the main device 200 along the lowermost portion of the second transport path CP2. A reading area R1 is predetermined in the contact portion 330 . The object A2 transported in the second transport path CP2 passes over the reading area R1.

The image reading unit 340 is a CIS (Contact Image Sensor). Image reading unit 340 is provided inside main unit 200 at a position near the top surface. Further, the image reading section 340 emits light from a position below the contact section 330 toward the reading region R1. The image sensor 340 generates image data representing an image of the object A2 by photoelectrically converting light reflected from the object A2 passing through the reading region R1, and outputs the image data to the control unit 27. FIG.

The acquisition processing unit 27</b>A may acquire the signal ES<b>2 from the second sensor unit 33 instead of the first sensor unit 24 . In this case, the determination processing unit 27B and the timing processing unit 27C execute the processes shown in FIGS. 6A to 6C based on the signal ES2 instead of the signal ES1. The detection processing unit 27D detects whether or not the object A2 is double-fed on the second transport path CP2 according to the determination result of the determination processing unit 27B. The transportation control unit 27E controls transportation of the object A2 by the second transportation unit 32 according to the detection result of the detection processing unit 27D.

REFERENCE SIGNS LIST 100 image forming apparatus 200 main unit 23 first conveying section 24 first sensor section 300 image reading device 32 second conveying section 33 second sensor section 400 conveying device 27 control section 27A acquisition processing section 27B determination processing section 27C timing processing section 27D Detection processing unit 27E Conveyance control unit

Claims (10)

an acquisition processing unit that acquires a signal based on an ultrasonic wave emitted to an object conveyed in a specific direction;
Determining whether or not a first time taken for the signal level to change from a predetermined first level threshold to a second level threshold smaller than the first level threshold is greater than or equal to a predetermined first time threshold. a determination processing unit;
with
The determination processing unit, when determining that the first time period is not equal to or greater than the first time threshold value, determines that a second time period during which the level of the signal is equal to or less than the first level threshold value is longer than the first time threshold value. A judging device for further judging whether the time is equal to or greater than the two-hour threshold . The first time threshold is determined based on the speed at which the object is conveyed in the specific direction and the distance from the end of the object on the side of the specific direction in the direction opposite to the specific direction. ,
The determination device according to claim 1. The first level threshold and the second level threshold are determined based on the thickness of the object in an intersecting direction that intersects the specific direction,
The determination device according to claim 1 or 2. The second time threshold is predetermined based on the speed at which the object is conveyed in the specific direction and the length of the object in the specific direction,
The determination device according to any one of claims 1 to 3 . a sensor unit that emits ultrasonic waves to the object and outputs the signal whose level changes according to the incident wave from the object;
A determination device according to any one of claims 1 to 4 ;
A conveying device comprising a A detection processing unit that detects the presence or absence of multi-feeding of the objects according to the determination result of the determination device,
The conveying device according to claim 5 . The detection processing unit detects that there is no double feeding when the determination processing unit determines that the first time is equal to or greater than the first time threshold,
The transport device further comprises a transport control unit that further transports the object downstream in the specific direction when it is detected that there is no double feeding.
The conveying device according to claim 6 . The detection processing unit detects that there is the double feeding when the determination processing unit determines that the first time is not equal to or greater than the first time threshold,
The transport control unit is capable of stopping transport of the object in the specific direction when it is detected that there is the double feeding.
The conveying device according to claim 7 . The determination device according to claims 1 to 4 , or the transport device according to any one of claims 5 to 8 ,
an image reader. The determination device according to claims 1 to 4 , or the transport device according to any one of claims 5 to 8 ,
An image forming apparatus comprising:

Images