MEDIUM EXTRACTING DEVICE, CONTROL METHOD, AND CONTROL PROGRAM

Abstract

To provide a medium discharge device, a control method, and a control program capable of accurately detecting crawl of a medium.SOLUTION: A medium discharge device includes a discharge part for discharging a medium, a discharge table for placing the medium discharged by the discharge part, an imaging part that captures the medium discharged by the discharge part and generates a medium image, a determination part that determines whether or not the medium discharged by the discharge part has crawled under the medium already placed on the discharge table based on the medium image, and a control part that executes an abnormality processing when the determination part determines that the medium has crawled.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a medium ejection device, a control method, and a control program, and more particularly to a medium ejection device that places ejected media on an ejection tray, a control method, and a control program. [Background technology]

[0002] A medium ejection device such as a scanner takes an image of a medium while transporting it and ejects it onto a ejection tray. In such a medium ejection device, when a medium is ejected onto the ejection tray, it may slip under media already placed on the ejection tray, causing the order of the media to be changed (so-called tramps). If a user does not notice that the order of the media has been changed, the media may be stored in the changed order.

[0003] A paper feeder is disclosed that stacks and loads the paper discharged from a previous device on a paper loading tray in order (see Patent Document 1). This paper feeder has a roller that slides against the paper surface on the leading edge side of the succeeding paper discharged onto the paper loading tray, and a rotary encoder that rotates together with the roller, and detects the arrival of the leading edge of the succeeding paper by the rotation of the rotary encoder accompanying the rotation of the roller. In this way, the paper feeder detects that the succeeding paper to be discharged later has been stacked on top of the preceding paper that was previously discharged onto the paper loading tray from the previous device.

[0004] A printer device has been disclosed that is equipped with a tray for receiving recording paper and a pair of impellers for receiving recording paper fed onto the tray, and that prevents subsequent recording paper from slipping under preceding recording paper by the rotation of the impellers (see Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-298513 A [Patent Document 2] Japanese Patent Application Publication No. 10-218465 Summary of the Invention [Problem to be solved by the invention]

[0006] A medium ejection device is required to accurately detect whether an ejected medium has slipped under a medium already placed on the ejection tray.

[0007] An object of the present invention is to provide a medium ejection device, a control method, and a control program that are capable of detecting the slippage of a medium with high accuracy. [Means for solving the problem]

[0008] A medium ejection device according to one aspect of the present invention includes an ejection unit that ejects a medium, an ejection tray on which the medium ejected by the ejection unit is placed, and a device for holding the medium ejected by the ejection unit. each The image was taken Multiple Media images Sequential An imaging unit that generates Multiple Media image Difference between or similarity of multiple media images The device has a determination unit that determines whether or not the medium being discharged by the discharge unit has slipped under a medium already placed on the discharge tray based on the information, and a control unit that executes abnormality processing when the determination unit determines that the medium has slipped under the medium. Furthermore, a media discharge device according to one aspect of the present invention includes a first imaging unit that generates an input image of the medium being transported, a discharge unit that discharges the medium, a discharge tray on which the medium discharged by the discharge unit is placed, a second imaging unit that generates a medium image of the medium discharged by the discharge unit, a determination unit that determines whether the medium discharged by the discharge unit has slipped under a medium already placed on the discharge tray by comparing the input image with the medium image, and a control unit that executes abnormality processing when the determination unit determines that the medium has slipped under.

[0009] A control method according to one aspect of the present invention is a control method for a medium ejection device, comprising: ejecting a medium by an ejection unit; placing the medium ejected by the ejection unit on an ejection tray; and photographing the medium ejected by the ejection unit by an imaging unit. each The image was taken Multiple Media images Sequential Generate, Multiple Media image Difference between or similarity of multiple media images Based on this, it is determined whether or not the medium being discharged by the discharge unit has slipped under a medium already placed on the discharge tray, and if it is determined that the medium has slipped under, abnormality processing is performed. Furthermore, a control method according to one aspect of the present invention is a control method for a media discharge device, in which a first imaging unit generates an input image of the medium being transported, the discharge unit discharges the medium, the medium discharged by the discharge unit is placed on the discharge tray, and a second imaging unit generates a medium image of the medium discharged by the discharge unit, and by comparing the input image with the medium image, it is determined whether the medium discharged by the discharge unit has slipped under a medium already placed on the discharge tray, and if it is determined that the medium has slipped under, abnormality processing is performed.

[0010] A control program according to an aspect of the present invention includes a discharge unit that discharges a medium, a discharge table on which the medium discharged by the discharge unit is placed, and a control unit that controls the medium discharged by the discharge unit. each The image was taken Multiple Media images Sequential and an imaging unit that generates a medium ejection device, Multiple Media image Difference between or similarity of multiple media images Based on this, it is determined whether or not the medium discharged by the discharge section has slipped under a medium already placed on the discharge table, and the medium discharge device is caused to execute abnormality processing when it is determined that the medium has slipped under. In addition, a control program according to one aspect of the present invention is a control program for a media discharge device having a first imaging unit that generates an input image of the medium being transported, a discharge unit that discharges the medium, a discharge tray on which the medium discharged by the discharge unit is placed, and a second imaging unit that generates a medium image of the medium discharged by the discharge unit, and causes the media discharge device to determine whether the medium discharged by the discharge unit has slipped under a medium already placed on the discharge tray by comparing the input image with the medium image, and to execute abnormality processing if it is determined that the medium has slipped under. Effect of the Invention

[0011] According to the present invention, the medium ejection device, the control method, and the control program are capable of detecting the slippage of a medium with high accuracy. [Brief description of the drawings]

[0012] [Figure 1] 1 is a perspective view showing a medium ejection device 100 according to an embodiment. [Diagram 2] 2 is a diagram for explaining a transport path inside the medium ejection device 100. FIG. [Diagram 3] 1 is a block diagram showing a schematic configuration of a medium ejection device 100. FIG. [Figure 4] FIG. 2 is a diagram showing a schematic configuration of a storage device 140 and a processing circuit 150. [Diagram 5] 10 is a flowchart illustrating an example of the operation of a medium reading process. [Figure 6] 13 is a flowchart showing an example of the operation of a determination process. [Figure 7] 11A and 11B are schematic diagrams for explaining an example of a medium image and a difference image. [Figure 8] 11A and 11B are schematic diagrams for explaining an example of a medium image and a difference image. [Figure 9] FIG. 13 is a diagram showing a schematic configuration of another processing circuit 250. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a medium ejection device according to one aspect of the present invention will be described with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to the embodiment, but extends to the inventions described in the claims and their equivalents.

[0014] 1 is a perspective view showing a medium ejection device 100 configured as an image scanner. The medium ejection device 100 transports a medium, which is an original document, and captures an image of the medium. The medium is paper, cardboard, a card, a booklet, a passport, or the like. The medium ejection device 100 may be a facsimile, a copier, a multifunction printer (MFP, Multifunction Peripheral), or the like. Note that the medium to be transported may not be an original document, but may be a printed object, or the like, and the medium ejection device 100 may be a printer, or the like.

[0015] The medium ejection device 100 includes a lower housing 101, an upper housing 102, a placement stand 103, an ejection stand 104, an operation device 105, a display device 106, and the like.

[0016] Upper housing 102 is disposed in a position that covers the top surface of medium ejection device 100, and engages with lower housing 101 by a hinge so that it can be opened and closed when loading media, cleaning the inside of medium ejection device 100, and the like.

[0017] The placement stage 103 is engaged with the lower housing 101 so that the medium to be transported can be placed thereon. The ejection stage 104 is engaged with the lower housing 101 so that the ejected medium can be held thereon.

[0018] The operation device 105 has an input device such as a button and an interface circuit for acquiring a signal from the input device, accepts an input operation by a user, and outputs an operation signal according to the input operation by the user. The display device 106 has a display including a liquid crystal, an organic EL (Electro-Luminescence), or the like, and an interface circuit for outputting image data to the display, and displays the image data on the display.

[0019] FIG. 2 is a diagram for explaining a transport path inside medium ejection device 100. As shown in FIG.

[0020] The transport path inside the media ejection device 100 includes a first media sensor 111, a feed roller 112, a brake roller 113, a first transport roller 114, a second transport roller 115, a second media sensor 116, a first imaging device 117, a first ejection roller 118, a second ejection roller 119, and a second imaging device 120, etc.

[0021] The number of each of the feed roller 112, the brake roller 113, the first conveyor roller 114, the second conveyor roller 115, the first discharge roller 118, and / or the second discharge roller 119 is not limited to one, and may be more than one. In this case, the multiple feed rollers 112, the brake roller 113, the first conveyor roller 114, the second conveyor roller 115, the first discharge roller 118, and / or the second discharge roller 119 are arranged at intervals in the width direction perpendicular to the medium conveying direction A1.

[0022] The top surface of the lower housing 101 forms a lower guide 107a of the medium transport path, and the bottom surface of the upper housing 102 forms an upper guide 107b of the medium transport path. In Fig. 2, an arrow A1 indicates the medium transport direction. Hereinafter, "upstream" refers to the upstream side of the medium transport direction A1, and "downstream" refers to the downstream side of the medium transport direction A1.

[0023] The first medium sensor 111 is disposed upstream of the feed roller 112 and the brake roller 113. The first medium sensor 111 has a contact detection sensor and detects whether or not a medium is placed on the placement table 103. The first medium sensor 111 generates and outputs a first medium signal whose signal value changes depending on whether or not a medium is placed on the placement table 103. Note that the first medium sensor 111 is not limited to a contact detection sensor, and any other sensor capable of detecting the presence or absence of a medium, such as a light detection sensor, may be used as the first medium sensor 111.

[0024] The feed roller 112 is provided in the lower housing 101 and feeds the media placed on the mounting table 103 from the bottom up. The brake roller 113 is provided in the upper housing 102 and disposed opposite the feed roller 112. Alternatively, the feed roller 112 may be provided in the upper housing 102 and the brake roller 113 in the lower housing 101, and the feed roller 112 may feed the media placed on the mounting table 103 from the top up.

[0025] The first conveyor roller 114 and the second conveyor roller 115 are disposed opposite each other on the downstream side of the feed roller 112 in the medium conveying direction A1. The first conveyor roller 114 and the second conveyor roller 115 convey the medium fed by the feed roller 112 and the brake roller 113 to the first imaging device 117.

[0026] The second medium sensor 116 is disposed downstream of the first transport roller 114 and the second transport roller 115 and upstream of the first imaging device 117, and detects a medium transported to that position. The second medium sensor 116 includes a light emitter and a light receiver provided on one side of the medium transport path, and a reflecting member such as a mirror provided at a position facing the light emitter and the light receiver across the medium transport path. The light emitter is an LED (Light Emitting Diode) or the like, and emits light toward the medium transport path. On the other hand, the light receiver receives the light emitted by the light emitter and reflected by the reflecting member. When a medium is present at a position facing the second medium sensor 116, the light emitted from the light emitter is blocked by the medium, and the light receiver does not detect the light emitted from the light emitter. The light receiver generates and outputs a second medium signal whose signal value changes depending on whether a medium is present or not at the position of the second medium sensor 116 based on the intensity of the received light.

[0027] A light guide tube may be used instead of the reflecting member. The light emitter and the light receiver may be provided facing each other across the medium transport path. The second medium sensor 116 may detect the presence of the medium using a contact detection sensor that passes a predetermined current when the medium is in contact or when the medium is not in contact.

[0028] The first imaging device 117 includes a front imaging device 117a and a back imaging device 117b arranged opposite to each other across the medium transport path. The front imaging device 117a has a line sensor using a CIS (Contact Image Sensor) of a life-size optical system type having imaging elements using CMOS (Complementary Metal Oxide Semiconductor) linearly arranged in the main scanning direction. The front imaging device 117a also has a lens that forms an image on the imaging element, and an A / D converter that amplifies and analog-to-digital (A / D) converts the electrical signal output from the imaging element. The front imaging device 117a images the surface of the transported medium to generate an input image and output it according to control from a processing circuit described later.

[0029] Similarly, the backside imaging device 117b has a line sensor using a CIS of a life-size optical system type having imaging elements using CMOS arranged linearly in the main scanning direction. The backside imaging device 117b also has a lens that forms an image on the imaging element, and an A / D converter that amplifies and analog-to-digital (A / D) converts the electrical signal output from the imaging element. The backside imaging device 117b images the back side of the medium being conveyed under the control of a processing circuit described later, generates an input image, and outputs it.

[0030] Note that the medium ejection device 100 may have only one of the front side imaging device 117a and the back side imaging device 117b arranged to read only one side of the medium. Also, instead of a CIS line sensor of an equal magnification optical system type having a CMOS imaging element, a CIS line sensor of an equal magnification optical system type having a CCD (Charge Coupled Device) imaging element may be used. Also, a reduction optical system type line sensor having a CMOS or CCD imaging element may be used.

[0031] The first discharge roller 118 and the second discharge roller 119 are an example of a discharge section, and are disposed facing each other downstream of the first imaging device 117 in the medium conveying direction A1. The first discharge roller 118 and the second discharge roller 119 discharge the medium that has been conveyed by the first conveying roller 114 and the second conveying roller 115 and imaged by the first imaging device 117 to the discharge tray 104.

[0032] The second imaging device 120 is an example of an imaging section, and is provided so as to be able to image the discharge tray 104 or a medium discharged to the discharge tray 104. The second imaging device 120 has an image sensor of a life-size optical system type having imaging elements based on CMOS arranged two-dimensionally. The second imaging device 120 also has a lens that forms an image on the imaging element, and an A / D converter that amplifies and analog-to-digital (A / D) converts the electrical signal output from the imaging element. The second imaging device 120 generates and outputs a medium image obtained by capturing an image of the medium discharged to the discharge tray 104 by the first discharge roller 118 and the second discharge roller 119 under control of a processing circuit described later. The second imaging device 120 periodically captures an image of the discharged medium, and sequentially generates a plurality of medium images.

[0033] Note that, instead of an image sensor of the life-size optical system type equipped with a CMOS image sensor, an image sensor of the life-size optical system type equipped with a CCD image sensor may be used, or an image sensor of the reduction optical system type equipped with a CMOS or CCD image sensor may be used.

[0034] The medium placed on the mounting table 103 is transported between the lower guide 107a and the upper guide 107b in the medium transport direction A1 by the rotation of the feed roller 112 in the direction of the arrow A2 in Fig. 2, i.e., the medium feed direction. The brake roller 113 rotates in the direction of the arrow A3, i.e., the opposite direction to the medium feed direction, when transporting the medium. When multiple media are placed on the mounting table 103, the feed roller 112 and the brake roller 113 function to separate only the media placed on the mounting table 103 that are in contact with the feed roller 112. This limits the transport of media other than the separated media (preventing double feeding).

[0035] The medium is fed between the first transport roller 114 and the second transport roller 115 while being guided by the lower guide 107a and the upper guide 107b. The medium is fed between the front side imaging device 117a and the back side imaging device 117b as the first transport roller 114 and the second transport roller 115 rotate in the directions of the arrows A4 and A5, respectively. The medium read by the first imaging device 117 is discharged onto the discharge tray 104 as the first discharge roller 118 and the second discharge roller 119 rotate in the directions of the arrows A6 and A7, respectively. The discharge tray 104 holds the medium to be discharged by the first discharge roller 118 and the second discharge roller 119.

[0036] FIG. 3 is a block diagram showing a schematic configuration of the medium ejection device 100. As shown in FIG.

[0037] In addition to the components described above, the medium ejection device 100 further includes a motor 131, an interface device 132, a storage device 140, a processing circuit 150, and the like.

[0038] The motor 131 has one or more motors, and rotates the feed roller 112, the brake roller 113, the first conveyor roller 114, the second conveyor roller 115, the first discharge roller 118, and the second discharge roller 119 to convey the medium in response to a control signal from the processing circuit 150. Note that one of the first conveyor roller 114 and the second conveyor roller 115 may be a driven roller that rotates following the other roller. Also, one of the first discharge roller 118 and the second discharge roller 119 may be a driven roller that rotates following the other roller.

[0039] The interface device 132 has an interface circuit conforming to a serial bus such as USB, and is electrically connected to an information processing device (not shown, for example, a personal computer, a mobile information terminal, etc.) to transmit and receive input images and various information. Also, instead of the interface device 132, a communication unit having an antenna for transmitting and receiving wireless signals and a wireless communication interface device for transmitting and receiving signals through a wireless communication line in accordance with a predetermined communication protocol may be used. The predetermined communication protocol is, for example, a wireless LAN (Local Area Network). The communication unit may have a wired communication interface device for transmitting and receiving signals through a wired communication line in accordance with a communication protocol such as a wired LAN.

[0040] The storage device 140 includes a memory device such as a random access memory (RAM) or a read only memory (ROM), a fixed disk device such as a hard disk, or a portable storage device such as a flexible disk or an optical disk. The storage device 140 also stores computer programs, databases, tables, and the like used for various processes of the medium ejection device 100. The computer programs may be installed in the storage device 140 from a computer-readable portable recording medium using a known setup program or the like. The portable recording medium is, for example, a compact disc read only memory (CD-ROM), a digital versatile disc read only memory (DVD-ROM), or the like.

[0041] The processing circuit 150 operates based on a program previously stored in the storage device 140. The processing circuit is, for example, a CPU (Central Processing Unit). The processing circuit 150 may be, for example, a DSP (digital signal processor), an LSI (large scale integration), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable Gate Array).

[0042] The processing circuit 150 is connected to the operation device 105, the display device 106, the first medium sensor 111, the second medium sensor 116, the first imaging device 117, the second imaging device 120, the motor 131, the interface device 132, the storage device 140, etc., and controls each of these components. The processing circuit 150 performs drive control of the motor 131, image capture control of the first imaging device 117, etc., acquires an input image from the first imaging device 117, and transmits it to the information processing device via the interface device 132. The processing circuit 150 also determines whether or not a medium has slipped in based on a medium image generated by the second imaging device 120.

[0043] FIG. 4 is a diagram showing a schematic configuration of the storage device 140 and the processing circuit 150. As shown in FIG.

[0044] 4, the storage device 140 stores a control program 141, a determination program 142, and the like. Each of these programs is a functional module implemented by software that runs on a processor. The processing circuit 150 reads each program stored in the storage device 140 and operates according to the read program. In this way, the processing circuit 150 functions as a control unit 151 and a determination unit 152.

[0045] FIG. 5 is a flowchart showing an example of the operation of the medium reading process of the medium ejection device 100.

[0046] An example of the operation of the medium reading process of medium ejection device 100 will be described below with reference to the flowchart shown in Fig. 5. Note that the flow of the operation described below is executed mainly by processing circuit 150 in cooperation with each element of medium ejection device 100 based on a program stored in memory device 140 in advance.

[0047] First, the control unit 151 waits until a user inputs an instruction to read a medium using the operation device 105 or an information processing device, and an operation signal instructing the user to read a medium is received from the operation device 105 or the interface device 132 (step S101).

[0048] Next, control unit 151 acquires a first medium signal from first medium sensor 111, and determines whether or not a medium is placed on placement table 103 based on the acquired first medium signal (step S102). If no medium is placed on placement table 103, control unit 151 ends the series of steps.

[0049] On the other hand, when a medium is placed on the placement table 103, the control unit 151 drives the motor 131. The control unit 151 rotates the feed roller 112, the brake roller 113, the first conveyor roller 114, the second conveyor roller 115, the first discharge roller 118, and / or the second discharge roller 119 to convey the medium (step S103).

[0050] Next, the control unit 151 determines whether or not the determination unit 152 has determined that the medium has slipped in during a determination process executed in parallel with the medium reading process (step S104). During the determination process, the determination unit 152 determines whether or not the medium has slipped in based on the medium image. Details of the determination process will be described later.

[0051] When the determination unit 152 determines that the medium has slipped in during the determination process, the control unit 151 executes an abnormality process (step S105). As the abnormality process, the control unit 151 notifies the user by displaying information indicating that the medium has slipped in on the display device 106 or by transmitting the information to the information processing device via the interface device 132. As the abnormality process, the control unit 151 may stop the motor 131 and stop the transport and discharge of the medium by the feed roller 112, the brake roller 113, the first transport roller 114, the second transport roller 115, the first discharge roller 118, and the second discharge roller 119. In this case, the control unit 151 ends the medium reading process after executing the abnormality process. Note that, as the abnormality process, the control unit 151 may discharge the medium currently being transported and then stop the medium reading process. On the other hand, when it is not determined that the medium has slipped in during the determination process, the control unit 151 does not execute the abnormality process.

[0052] Next, the control unit 151 determines whether the entire conveyed medium has been imaged (step S106). The control unit 151 determines whether the rear end of the medium has passed the position of the second medium sensor 116 based on, for example, the second medium signal received from the second medium sensor 116. The control unit 151 periodically acquires the second medium signal from the second medium sensor 116, and determines that the rear end of the medium has passed the position of the second medium sensor 116 when the signal value of the second medium signal changes from a value indicating the presence of the medium to a value indicating the absence of the medium. The control unit 151 determines that the rear end of the medium has passed the imaging position of the first imaging device 117 and that the entire conveyed medium has been imaged when a first predetermined time has elapsed since the rear end of the medium passed the position of the second medium sensor 116. The first predetermined time is set to a value that is the time required for the medium to move from the second medium sensor 116 to the imaging position plus a margin. The control unit 151 may determine that the entire conveyed medium has been imaged when a predetermined time has elapsed since the feeding of the medium began.

[0053] If the entire conveyed medium has not yet been imaged, the control unit 151 returns the process to step S104, and repeats the processes of steps S104 to S106.

[0054] On the other hand, if the entire transported medium has been imaged, the control unit 151 acquires an input image from the first imaging device 117 and outputs the acquired input image by transmitting it to the information processing device via the interface device 132 (step S107).

[0055] Next, control unit 151 determines whether or not a medium remains on mounting table 103 based on the first medium signal received from first medium sensor 111 (step S108). If a medium remains on mounting table 103, control unit 151 returns the process to step S104, and repeats the processes of steps S104 to S107.

[0056] On the other hand, if no media remain on the placement table 103, the control unit 151 stops the motor 131. As a result, the control unit 151 stops the feed roller 112, the brake roller 113, the first conveyor roller 114, the second conveyor roller 115, the first discharge roller 118, and the second discharge roller 119 (step S109), and the series of steps ends.

[0057] FIG. 6 is a flowchart showing an example of the operation of the determination process of the medium ejection device 100.

[0058] An example of the operation of the determination process of medium ejection device 100 will be described below with reference to the flowchart shown in Fig. 6. The flow of the operation described below is executed mainly by processing circuit 150 in cooperation with each element of medium ejection device 100 based on a program previously stored in storage device 140. The flow of the operation shown in Fig. 6 is executed while the medium is being ejected. The processing of steps S201 to S206 shown in Fig. 6 is executed at regular intervals. The regular intervals are set to a time at which the position of the ejected medium changes reliably in multiple medium images continuously generated by second imaging device 120.

[0059] First, the determination unit 152 acquires a medium image from the second imaging device 120, and stores the acquired medium image in the storage device 140 in association with the current time (step S201).

[0060] Next, the determination unit 152 generates a difference image from the multiple medium images acquired in succession (step S202). The determination unit 152 generates the difference image by inter-frame difference processing. The determination unit 152 calculates the absolute value of the difference between the gradation values ​​of each pixel for each corresponding pixel between the latest medium image and the medium image acquired immediately before as a difference value, and generates a difference image in which the calculated difference value is the gradation value of the corresponding pixel. The gradation value is a luminance value or a color value (RGB value), etc.

[0061] Next, the determination unit 152 detects the leading edge position of the medium currently being discharged from the generated difference image, and stores the detected leading edge position in the storage device 140 in association with the current time (step S203). For example, the determination unit 152 generates a binary image in which pixels in the difference image whose gradation value is less than the binarization threshold are invalid pixels, and pixels whose gradation value is equal to or greater than the binarization threshold are valid pixels. The binarization threshold is set to, for example, the average value of the maximum and minimum values ​​of the gradation range. The determination unit 152 calculates the number of valid pixels for each line orthogonal to the medium conveying direction A1 in the generated binary image. The determination unit 152 detects the position of the line located at the most downstream side in the medium conveying direction A1 among the lines whose number of valid pixels is equal to or greater than the pixel number threshold as the leading edge position of the medium. The pixel number threshold is set to any natural number equal to or greater than 1.

[0062] Next, the determination unit 152 determines whether the detected leading edge position has changed (step S204). The determination unit 152 calculates the distance (number of pixels) between the latest leading edge position and the leading edge position detected immediately before, and determines whether the calculated distance is equal to or greater than the distance threshold. If the calculated distance is equal to or greater than the distance threshold, the determination unit 152 determines that the detected leading edge position has changed, and if the calculated distance is less than the distance threshold, the determination unit 152 determines that the detected leading edge position has not changed. The distance threshold is set to a value obtained by subtracting a margin from the number of pixels equivalent to the medium movement distance calculated by multiplying the image capture interval of each medium image by the medium transport speed, for example.

[0063] If the leading edge position has changed, the judgment unit 152 judges that the medium being discharged by the first discharge roller 118 and the second discharge roller 119 has not yet slipped under the medium already placed on the discharge tray 104 (step S205), and returns the process to step S201.

[0064] On the other hand, if the leading edge position has not changed, the judgment unit 152 judges that the medium being discharged by the first discharge roller 118 and the second discharge roller 119 has slipped under the medium already placed on the discharge tray 104 (step S206), and returns the process to step S201.

[0065] 7 and 8 are schematic diagrams for explaining an example of a medium image and a difference image.

[0066] In FIG. 7, images P10 to P18 are medium images generated sequentially when the media M1 and M2 are discharged in succession and the medium does not slip under. The medium image P10 does not include a medium, but only the discharge tray 104. The medium image P11 includes the medium M1 that has started to be discharged, the medium images P12 and P13 include the medium M1 that gradually progresses downstream in the medium transport direction A1, and the medium image P14 includes the medium M1 that has reached the downstream end of the discharge tray 104. The medium image P15 includes the medium M2 that has started to be discharged in addition to the medium M1, the medium images P16 and P17 include the medium M2 that gradually progresses downstream in the medium transport direction A1, and the medium image P18 includes the medium M2 that has reached the downstream end of the discharge tray 104. As shown in the medium images P17 and P18, the medium M2 is arranged above the medium M1 without slipping under the medium M1.

[0067] Images D11 to D18 are difference images generated from images P10 and P11, images P11 and P12, images P12 and P13, images P13 and P14, images P14 and P15, images P15 and P16, images P16 and P17, and images P17 and P18, respectively. In each difference image, the gradation value of a pixel corresponding to an area where an object is stationary between two corresponding medium images is approximately 0, and the pixel has a black color. On the other hand, in each difference image, the gradation value of a pixel corresponding to an area where an object is moving between two corresponding medium images is large, and the pixel has a white color. However, in each difference image, even if a pixel corresponds to an area where an object is moving between two corresponding medium images, if the gradation value (brightness value or color value) of the object in the pixel is approximately the same, the gradation value of the pixel is small.

[0068] When the brightness or color of the leading edge (downstream edge) of the discharged medium is different from the brightness or color of the discharge table 104, the gradation value of the pixel corresponding to the leading edge E of the medium M1 or M2 moving on the discharge table 104 becomes large (the pixel has white color) as shown in the difference images D11 to D15. In addition, since a shadow is formed around the edge of the discharged medium by the edge, the gradation value of the pixel corresponding to the leading edge E of the medium M2 moving on the medium M1 becomes large (the pixel has white color) as shown in the difference images D16 to D18. Therefore, in each of the difference images D11 to D18, the leading edges E of the medium M1 and M2 are detected well based on the gradation value of each pixel. In addition, as shown in each of the difference images D16 to D18, when the medium M2 is discharged on the medium M1, the position of the leading edge E of the medium M2 continues to change with the movement of the medium M2.

[0069] On the other hand, in Fig. 8, images P20 to P28 are medium images generated sequentially when media M1 and M2 are successively discharged and media slippage occurs. The medium images P20 to P28 are images generated at the same timing as the medium images P10 to P18 in Fig. 7. However, in the medium images P27 and P28, the medium M2 slips under the medium M1.

[0070] The images D21 to D28 are difference images generated from the images P20 and P21, the images P21 and P22, the images P22 and P23, the images P23 and P24, the images P24 and P25, the images P25 and P26, the images P26 and P27, and the images P27 and P28, respectively. As shown in each of the difference images D26 to D28, when the medium M2 is under the medium M1, the leading edge of the medium M2 is hidden by the medium M1. In this case, in each of the difference images D26 to D28, a line including pixels whose luminance value or color value has changed due to the movement of the characters, images, patterns, etc. in the medium M2 near the trailing edge of the medium M1 is detected as the leading edge E of the medium. That is, in each of the difference images D26 to D28, the leading edge E is detected near the trailing edge of the medium M1, and the position of each leading edge E hardly changes.

[0071] Therefore, the determination unit 152 can accurately determine whether or not the medium has slipped under, based on whether or not the position of the leading edge E detected from the differential image has changed.

[0072] In this way, the determination unit 152 determines, based on the medium image, whether or not the medium discharged by the first discharge roller 118 and the second discharge roller 119 has slipped under a medium already placed on the discharge tray 104. This allows the determination unit 152 to accurately determine whether or not the medium has slipped under.

[0073] In particular, the determination unit 152 determines whether or not the slippage of a medium has occurred based on the difference between a plurality of medium images. This allows the determination unit 152 to determine whether or not the slippage of a medium has occurred in a short time, and reduces the processing load of the determination process.

[0074] Furthermore, the determination unit 152 determines whether or not the medium has slipped under based on the leading edge position of the medium. This allows the determination unit 152 to determine whether or not the medium has slipped under in a shorter time, thereby reducing the processing load of the determination process.

[0075] As described above in detail, medium ejection device 100 detects a change in the order of media on ejection tray 104 (a trump) based on a medium image captured of the media being ejected onto ejection tray 104. This enables medium ejection device 100 to accurately detect slippage of media. Therefore, when slippage of media occurs, medium ejection device 100 can notify the user of this or stop the transport and ejection of the media, and allow the user to change the order of the media, making it possible to maintain the media in the correct order.

[0076] Note that the medium ejection device 100 may use other image processing techniques to determine whether or not the medium has slipped in, rather than using the difference between multiple medium images. For example, the medium ejection device 100 uses pattern matching techniques to determine whether or not the medium has slipped in. In this case, the determination unit 152 determines whether or not the medium has been ejected based on the second medium signal received from the second medium sensor 116. The determination unit 152 determines that the medium has been ejected when a second predetermined time has elapsed since the rear end of the medium passed the position of the second medium sensor 116. The second predetermined time is set to a value obtained by adding a margin to the time required for the medium to move from the second medium sensor 116 to the ejection port.

[0077] Each time a medium is discharged, the determination unit 152 acquires a medium image of the discharged medium from the second imaging device 120, associates the acquired medium image with the current time, and stores the acquired medium image in the storage device 140. The determination unit 152 calculates the similarity between a medium image of a newly discharged medium and a medium image of a medium discharged immediately before. The determination unit 152 calculates, for example, a normalized cross-correlation value as the similarity. If the calculated similarity is equal to or greater than a determination threshold, the determination unit 152 determines that the media included in the two medium images are the same and that medium creeping has occurred. On the other hand, if the calculated similarity is less than the determination threshold, the determination unit 152 determines that the media included in the two medium images are different and that medium creeping has not occurred.

[0078] Alternatively, the determination unit 152 may determine whether or not the medium has slipped in by comparing the input image generated by the back side imaging device 117b with the medium image generated by the second imaging device 120. In this case, the determination unit 152 calculates the similarity between the input image generated by the back side imaging device 117b and the medium image generated by the second imaging device 120. If the calculated similarity is equal to or greater than the determination threshold, the determination unit 152 determines that the medium included in the input image and the medium included in the medium image are the same, and that the medium has not slipped in. On the other hand, if the calculated similarity is less than the determination threshold, the determination unit 152 determines that the medium included in the input image and the medium included in the medium image are different, and that the medium has slipped in.

[0079] These also enable medium ejection device 100 to accurately detect the slippage of a medium.

[0080] 9 is a diagram showing a schematic configuration of a processing circuit 250 in a medium ejection device according to another embodiment. The processing circuit 250 is used in place of the processing circuit 150 of the medium ejection device 100, and executes medium reading processing, determination processing, and the like in place of the processing circuit 150. The processing circuit 250 has a control circuit 251, a determination circuit 252, and the like. Note that each of these components may be formed from an independent integrated circuit, microprocessor, firmware, and the like.

[0081] The control circuit 251 is an example of a control unit, and has the same functions as the control unit 151. The control circuit 251 receives an operation signal from the operation device 105, a first medium signal from the first medium sensor 111, and a second medium signal from the second medium sensor 116. The control circuit 251 controls the motor 131 based on the received information, and also acquires an input image from the first imaging device 117 and outputs it to the interface device 132. The control circuit 251 also receives a determination result of the medium being submerged from the determination circuit 252, and executes abnormality processing based on the received determination result.

[0082] The determination circuit 252 is an example of a determination unit, and has the same function as the determination unit 152. The determination circuit 252 acquires a medium image from the second imaging device 120, stores it in the storage device 140, and determines whether or not the medium has slipped in based on the medium image.

[0083] As described above in detail, the medium ejection device is able to accurately detect the slipping of a medium even when using the processing circuit 250. [Explanation of symbols]

[0084] 100 medium discharge device, 104 discharge tray, 118 first discharge roller, 119 second discharge roller, 120 second imaging device, 151 control unit, 152 determination unit

Claims

1. a discharge unit that discharges the medium; a discharge tray on which the medium to be discharged by the discharge unit is placed; an imaging unit that sequentially generates a plurality of medium images by imaging each of the media discharged by the discharge unit; a determination unit that determines whether or not a medium being discharged by the discharge unit has slipped under a medium already placed on the discharge tray based on a difference between the plurality of medium images or a similarity between the plurality of medium images; a control unit that executes an abnormality process when the determination unit determines that a medium has slipped in; A medium ejection device comprising:

2. A first imaging unit that generates an input image by imaging a medium being transported; a discharge unit that discharges the medium; a discharge tray on which the medium to be discharged by the discharge unit is placed; a second imaging unit that captures an image of the medium discharged by the discharge unit and generates a medium image; a determination unit that determines whether or not the medium being discharged by the discharge unit has slipped under a medium already placed on the discharge tray by comparing the input image with the medium image; a control unit that executes an abnormality process when the determination unit determines that a medium has slipped in; A medium ejection device comprising:

3. The medium ejection device according to claim 1 , wherein the determination unit determines whether or not submersion of the medium has occurred based on a difference between the plurality of medium images and a leading edge position of the medium.

4. A method for controlling a medium ejection device, comprising: The medium is discharged by the discharge section. The medium to be discharged by the discharge unit is placed on a discharge table; an imaging unit sequentially generates a plurality of medium images by imaging the medium discharged by the discharge unit; determining whether or not a medium being discharged by the discharge unit has slipped under a medium already placed on the discharge tray based on a difference between the plurality of medium images or a similarity between the plurality of medium images; Execute abnormality processing when it is determined that a medium has slipped in. A control method comprising:

5. A method for controlling a medium ejection device, comprising: A first imaging unit captures an image of the medium being conveyed to generate an input image; The medium is discharged by the discharge section. The medium to be discharged by the discharge unit is placed on a discharge table; A second imaging unit captures an image of the medium discharged by the discharge unit to generate a medium image; determining whether or not the medium being discharged by the discharge unit has slipped under a medium already placed on the discharge tray by comparing the input image with the medium image; Execute abnormality processing when it is determined that a medium has slipped in. A control method comprising:

6. A control program for a medium ejection device having a discharge unit that ejects a medium, a discharge tray on which the medium ejected by the discharge unit is placed, and an imaging unit that sequentially generates a plurality of medium images by capturing images of the media ejected by the discharge unit, determining whether or not a medium being discharged by the discharge unit has slipped under a medium already placed on the discharge tray based on a difference between the plurality of medium images or a similarity between the plurality of medium images; Execute abnormality processing when it is determined that a medium has slipped in. A control program for causing the medium ejection device to execute the above steps.

7. A control program for a media discharge device having a first imaging unit that generates an input image of a medium being transported, a discharge unit that discharges the medium, a discharge table on which the medium discharged by the discharge unit is placed, and a second imaging unit that generates a media image of the medium discharged by the discharge unit, determining whether or not the medium being discharged by the discharge unit has slipped under a medium already placed on the discharge tray by comparing the input image with the medium image; Execute abnormality processing when it is determined that a medium has slipped in. A control program for causing the medium ejection device to execute the above steps.

Images