Sheet conveying device and recording medium

Abstract

The present invention provides a sheet conveying device and a storage medium capable of appropriately writing information to a target wireless tag. The sheet conveying device includes a conveying roller, a wireless tag communication device, a detection unit, a determination unit, and a control unit. The conveying roller conveys a sheet along a conveying path. The wireless tag communication device receives a response wave from a wireless tag attached to the sheet and writes information to the wireless tag. The detection unit detects the phase change of the response wave received by the wireless tag communication device. The determination unit determines the target wireless tag to be read or written based on the phase change detected by the detection unit. The control unit controls the wireless tag communication device to write information to the target wireless tag identified by the determination unit.

Description

Technical Field

[0001] Embodiments of the present invention relate to a sheet conveying device and a recording medium. Background Art

[0002] Image forming devices that convey sheets loaded on a paper feed cassette or manual feed tray and form images on the sheets are currently popular. Other image forming devices incorporate wireless tags attached to the sheets. To read and write information from the wireless tags attached to the sheets, the image forming devices are equipped with sheet conveying devices equipped with wireless tag communication devices.

[0003] As a related technology, there is a technique for performing reading and writing while changing the resonant frequency of a transmitting antenna so that the deviation between the resonant frequency of the transmitting antenna and the frequency of a transmission signal supplied to the transmitting antenna is within an allowable range in order to prevent degradation of communication performance due to a reduction in resonant current.

[0004] However, if information is to be written to the wireless tags of sheets moving along the conveyor path, the communication range of the wireless tag communication device becomes relatively large. Consequently, the wireless tag communication device may communicate with other wireless tags besides the one to which the information is being written, thereby writing information to these other wireless tags. Specifically, the wireless tag communication device may write information not to the wireless tags of sheets on the conveyor path, but to the wireless tags of sheets not on the conveyor path, such as sheets in the paper feed cassette. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a sheet conveying device and a storage medium capable of appropriately writing information to a target wireless tag.

[0006] A sheet conveying device according to an embodiment includes a conveying roller, a wireless tag communication device, a detection unit, a determination unit, and a control unit. The conveying roller conveys a sheet along a conveying path. The wireless tag communication device is capable of receiving a response wave from a wireless tag attached to the sheet and writing information to the wireless tag. The detection unit detects a phase change in the response wave received by the wireless tag communication device. The determination unit determines a target wireless tag to read or write based on the phase change detected by the detection unit. The control unit controls the wireless tag communication device to write information to the target wireless tag identified by the determination unit.

[0007] Another embodiment relates to a recording medium storing a program for causing a computer of a sheet conveying device to execute the following processing: detecting a change in a phase of a response wave received by a wireless tag communication device, determining a read / write target wireless tag based on the detected change in the phase, and controlling the wireless tag communication device to write information to the determined target wireless tag, wherein the sheet conveying device comprises: a conveying roller for conveying a sheet in a conveying path; and the wireless tag communication device capable of receiving the response wave from a wireless tag set on the sheet and writing information to the wireless tag. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is an explanatory diagram showing an example of the configuration of the image forming apparatus according to the embodiment.

[0009] Figure 2 This is an explanatory diagram showing an example of the movement of a sheet during double-sided printing.

[0010] Figure 3 This is a block diagram showing an example of the functional configuration of the sheet conveying device according to this embodiment.

[0011] Figure 4 It is an explanatory diagram showing an example of phase data stored in the phase storage unit.

[0012] Figure 5 This is a flowchart illustrating an example of processing related to reading and writing information between the image forming apparatus and the wireless tag.

[0013] Description of Reference Numerals

[0014] 10…image forming device, 33…conveyance path, 33a…first conveyance path, 33b…second conveyance path, 100…image formation control unit, 101…acquisition unit, 102…detection unit, 103…determination unit, 104…communication control unit, 201…wireless tag communication device, 220…storage device, 221…phase storage unit, 222…reference value storage unit, 250…sheet, 251…wireless tag, 251a…target wireless tag, 251b…non-target wireless tag. DETAILED DESCRIPTION

[0015] The sheet conveyor device of the embodiment is capable of appropriately writing information to wireless tags attached to sheets moving along a conveyor path. An image forming apparatus equipped with the sheet conveyor device of the embodiment is described in detail below. In the following description, components having the same or similar functions are denoted by the same reference numerals. Furthermore, descriptions of overlapping components may be omitted.

[0016] First, use Figure 1 The configuration of the image forming apparatus 10 according to the embodiment will be described. Figure 1 It is an explanatory diagram showing an example of the configuration of the image forming apparatus 10 according to the embodiment.

[0017] exist Figure 1 In the embodiment, the image forming apparatus 10 includes a control panel 13, a wireless tag communication device 201, and a printer unit 18. The printer unit 18 includes an image formation control unit 100, paper feed cassettes 16a and 16b, and the like. The image formation control unit 100 controls the control panel 13, the wireless tag communication device 201, and the printer unit 18. The image formation control unit 100 controls the conveyance of sheets in the printer unit 18. Controlling the conveyance of sheets includes controlling the conveyance timing, the stop position of sheets, the conveyance speed of sheets, and the like.

[0018] The control panel 13 includes input keys and a display unit. For example, the input keys receive user input. The display unit is, for example, a touch panel. The display unit receives user input and displays information to the user. For example, the control panel 13 displays items related to the operation of the image forming apparatus 10 on the display unit in a configurable manner. The control panel 13 notifies the image formation control unit 100 of the items set by the user.

[0019] Paper cassettes 16a and 16b store sheets with wireless tags attached. Of course, paper cassettes 16a and 16b can also store sheets without wireless tags. In the following description, unless otherwise specified, sheets are assumed to be sheets with wireless tags attached. The sheets can be made of materials such as paper or plastic film.

[0020] The printer unit 18 performs image formation. For example, the printer unit 18 forms an image indicated by image data on a sheet. In the following description, forming an image on a sheet is also referred to as "printing." In this embodiment, the printer unit 18 is a device that fixes a toner image, but is not limited to this and may also be an inkjet device.

[0021] The printer unit 18 includes an intermediate transfer belt 21. The printer unit 18 supports the intermediate transfer belt 21 via a driven roller 41, a pickup roller 40, and other components. The printer unit 18 rotates the intermediate transfer belt 21 in the direction of arrow m. The printer unit 18 includes four image forming units 22Y, 22M, 22C, and 22K. Each image forming unit 22Y, 22M, 22C, and 22K corresponds to Y (yellow), M (magenta), C (cyan), and K (black), respectively. The image forming units 22Y, 22M, 22C, and 22K are positioned below the intermediate transfer belt 21 along its rotational direction.

[0022] The following description will be made by taking the Y (yellow) image forming portion 22Y among the image forming portions 22Y, 22M, 22C, and 22K as an example. The image forming portions 22M, 22C, and 22K have the same configuration as the image forming portion 22Y, and therefore their detailed description will be omitted.

[0023] Image forming section 22Y includes charger 26, exposure scanner head 27, developing device 28, and photoconductor cleaner 29. Charger 26, exposure scanner head 27, developing device 28, and photoconductor cleaner 29 are arranged around photoconductor drum 24 that rotates in the direction of arrow n.

[0024] The image forming section 22Y includes a primary transfer roller 30. The primary transfer roller 30 is disposed so as to face the photosensitive drum 24 with the intermediate transfer belt 21 interposed therebetween.

[0025] The charger 26 uniformly charges the photosensitive drum 24. The exposure scanner 27 exposes the uniformly charged photosensitive drum 24 to form an electrostatic latent image on the photosensitive drum 24. The developing device 28 develops the electrostatic latent image on the photosensitive drum 24 using a two-component developer consisting of toner and carrier.

[0026] The primary transfer roller 30 primarily transfers the toner image formed on the photoconductive drum 24 to the intermediate transfer belt 21. The primary transfer rollers 30 of the image forming units 22Y, 22M, 22C, and 22K primarily transfer the toner image to the intermediate transfer belt 21, thereby forming a color toner image on the intermediate transfer belt 21. A color toner image is formed by sequentially superimposing toner images of Y (yellow), M (magenta), C (cyan), and K (black). The photoconductive cleaner 29 removes toner remaining on the photoconductive drum 24 after the primary transfer.

[0027] The printer unit 18 includes a secondary transfer roller 32. The secondary transfer roller 32 is positioned opposite the pickup roller 40 across the intermediate transfer belt 21. The secondary transfer roller 32 performs a secondary transfer of the color toner image on the intermediate transfer belt 21 onto a sheet. In the following description, "toner image" may refer to either a color toner image or a monochromatic toner image. Furthermore, a toner image may also be one using a decolorizable toner.

[0028] The conveyance path 33 is a path along which a sheet is conveyed by a plurality of conveyance rollers (e.g., conveyance roller 330). The conveyance path 33 includes a first conveyance path 33a, a second conveyance path 33b, and a third conveyance path 33c. The first conveyance path 33a is a conveyance path from the confluence 44a to the branch 44b. The second conveyance path 33b is a conveyance path passing through the duplex printing device 38. The second conveyance path 33b is a conveyance path different from the first conveyance path 33a, extending from the branch 44b to the confluence 44a. The third conveyance path 33c is a conveyance path from the branch 44b to the paper discharge tray 20.

[0029] A sheet is removed from any of the sheet loading sections in the paper feed cassette 16a, paper feed cassette 16b, or manual feed tray 16c. The sheet removed from the sheet loading section is temporarily stopped by the contact area between the two stopped registration rollers 31. At this point, the tip of the sheet contacts the registration rollers 31, correcting the sheet's skew. The image formation control unit 100 starts rotating the registration rollers 31 in accordance with the position of the toner image on the rotating intermediate transfer belt 21, moving the sheet to the position of the secondary transfer rollers 32.

[0030] The toner image formed on the intermediate transfer belt 21 is secondarily transferred onto a sheet by the secondary transfer roller 32. The secondarily transferred toner image is then fixed to the sheet by the fixing device 34. In this manner, an image is formed on the sheet under the control of the image formation control unit 100. The image formation control unit 100 conveys the sheet, to which the toner image has been fixed by the fixing device 34, along the third conveyance path 33c and then discharges the sheet.

[0031] The wireless tag communication device 201 includes a computing device, a storage device, and an antenna (not shown). The wireless tag in this embodiment is, for example, an RFID (Radio Frequency Identifier) ​​tag. The wireless tag communication device 201 transmits radio waves, for example, in the direction of arrow k. The wireless tag communication device 201 communicates with the wireless tag attached to the sheet via the antenna. Specifically, the wireless tag communication device 201 reads information from the wireless tag and writes information to the wireless tag.

[0032] The information written to the wireless tag includes, for example, information indicating the contents, information indicating the destination, and information printed on the sheet, when the sheet is used for logistics. In this embodiment, the wireless tag communication device 201 uses, for example, a 900 MHz band radio wave method (UHF). However, the RFID method and frequency band are not limited to this, and other methods and frequency bands may also be used.

[0033] Next, the behavior of the sheet during double-sided printing will be described.

[0034] Figure 2This is an explanatory diagram showing an example of the movement of a sheet during double-sided printing.

[0035] When performing duplex printing, a sheet 250 removed from any of the sheet loading sections of the paper feed cassette 16a, paper feed cassette 16b, and manual feed tray 16c is conveyed along the first conveyance path 33a. Specifically, the sheet 250 removed from the sheet loading section is skewed by the registration roller 31. The sheet 250 is then conveyed to the position of the secondary transfer roller 32 in accordance with the position of the toner image formed on the intermediate transfer belt 21. Furthermore, the toner image formed on the intermediate transfer belt 21 is secondarily transferred to the front surface of the sheet 250 by the secondary transfer roller 32. The toner image secondarily transferred to the front surface of the sheet 250 is then fixed by the fixing device 34.

[0036] The sheet 250, with an image formed on its surface, enters the third conveyance path 33c. The sheet 250 is then diverted and conveyed to the second conveyance path 33b under the control of the image formation control unit 100. The sheet 250 is then conveyed to the merging portion 44a via the second conveyance path 33b within the duplex printing device 38. The sheet 250 is further conveyed to the first conveyance path 33a via the registration rollers 31. Thus, after passing through the second conveyance path 33b, the sheet 250 is conveyed to the first conveyance path 33a with its back side facing the intermediate transfer belt 21.

[0037] The toner image formed on the intermediate transfer belt 21 is then secondarily transferred to the back side of the sheet 250 by the secondary transfer roller 32. Furthermore, the toner image secondarily transferred to the back side of the sheet 250 is fixed by the fixing device 34. The sheet 250 with the toner image formed on the back side is then delivered to the paper discharge tray 20 via the third conveyance path 33 c.

[0038] Next, use Figure 3 The sheet conveying device 50 included in the image forming apparatus 10 will be described. Figure 3 This is a block diagram showing an example of the functional configuration of the sheet conveying device 50 according to this embodiment.

[0039] exist Figure 3 In FIG. 5 , the sheet conveying device 50 includes an image formation control unit 100 , a wireless tag communication device 201 , a storage device 220 , and a conveying path 33 . The image formation control unit 100 controls the wireless tag communication device 201 according to a sheet conveying program stored in the storage device 220 .

[0040] Image formation control unit 100 is implemented by, for example, a CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit). Storage device 220 is implemented by, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disk Drive), or an SSD (Solid State Drive).

[0041] The wireless tag communication device 201 reads the ID of a wireless tag 251 placed on a sheet within the communication area at regular intervals (e.g., 10msec intervals). Specifically, the wireless tag communication device 201 transmits a signal (carrier wave) at regular intervals. Upon receiving the signal from the wireless tag communication device 201, the wireless tag 251 within the communication area receives power and activates. The wireless tag 251 then transmits a response wave containing pre-written ID data to the wireless tag communication device 201. The wireless tag communication device 201 then receives the response wave from the wireless tag 251 and obtains the ID data.

[0042] The wireless tag communication device 201 can communicate with the image formation control unit 100. The wireless tag communication device 201 receives response waves from the wireless tag 251 provided on the sheet 250 at regular intervals and transmits phase data indicating the phase of the received response waves to the image formation control unit 100.

[0043] The image formation control unit 100 includes an acquisition unit 101, a detection unit 102, a determination unit 103, and a communication control unit 104. Furthermore, the units 101 to 104 are not limited to being included in the image formation control unit 100, but may also be included in a control unit (such as another CPU or ASIC) independent of the image formation control unit 100.

[0044] The acquisition unit 101 acquires phase data of the response wave received by the wireless tag communication device 201 from the wireless tag 251. Specifically, the acquisition unit 101 acquires phase data of the response wave from the wireless tag communication device 201 at regular intervals (e.g., 10msec intervals). The acquisition unit 101 begins acquiring phase data each time printing of a sheet 250 begins.

[0045] The acquisition unit 101 stores the acquired response wave phase data in the phase storage unit 221 of the storage device 220 at regular intervals (e.g., 10 msec intervals). The phase of the response wave from the wireless tag 251 changes when the sheet 250 (wireless tag 251) moves. For example, the response wave from the sheet 250 (wireless tag 251) moving along the first conveyance path 33a changes according to a specific phase change pattern. On the other hand, if the sheet 250 (wireless tag 251) is not moving, the phase of the response wave from the wireless tag hardly changes.

[0046] Furthermore, in this embodiment, information can be written to the wireless tag 251 while the sheet 250 is moving along the conveyance path 33. Therefore, the communication area of ​​the wireless tag communication device 201 is set to a relatively large area. Specifically, the communication area of ​​the wireless tag communication device 201 is larger than when writing information to the wireless tag 251 while the sheet 250 is stopped. Therefore, when writing information to the wireless tag 251 of the sheet 250 moving along the conveyance path 33, the information may not be written to the target wireless tag 251, but may be written to other wireless tags 251 within the communication area.

[0047] Therefore, the detection unit 102 refers to the phase data stored in the phase storage unit 221 and detects the amount of change in the phase of the response wave acquired at regular intervals (hereinafter referred to as "phase change amount"). For example, the phase change amount is a value indicating the difference between the phases acquired at different timings. Specifically, the phase change amount is the difference between the phases stored at 10 msec intervals.

[0048] The identification unit 103 identifies the wireless tag 251 to be read / written (hereinafter referred to as the "target wireless tag 251a") based on the phase change of the response wave detected by the detection unit 102. Specifically, if the phase change of the response wave is greater than or equal to a predetermined value (e.g., 10°), the identification unit 103 identifies the wireless tag 251 having the phase change as the target wireless tag 251a.

[0049] The wireless tag 251 whose response wave phase change amount is greater than or equal to a predetermined value (target wireless tag 251a) is the wireless tag 251 of the sheet 250 currently traveling on the conveyance path 33 (e.g., the first conveyance path 33a). Thus, the identification unit 103 can identify the wireless tag 251 of the sheet 250 currently traveling on the conveyance path 33 (e.g., the first conveyance path 33a) as the target wireless tag 251a.

[0050] The communication control unit 104 controls the wireless tag communication device 201 to write information to the target wireless tag 251a specified by the specifying unit 103. The wireless tag communication device 201 writes information to the target wireless tag 251a according to the control of the communication control unit 104.

[0051] (Comparison of Change Patterns of Response Wave Phase)

[0052] The reference value storage unit 222 also pre-stores a reference value for the phase of the response wave when the sheet 250 moves along the conveyance path (hereinafter referred to as the "phase reference value"). Specifically, the phase reference value is a variation pattern (reference pattern) of the phase of the response wave accompanying the conveyance of the sheet 250. In this embodiment, the reference pattern is, for example, a variation pattern that increases by 20° every 10 msec.

[0053] For example, the phase reference value can be obtained by conveying a sheet 250 in an environment where no wireless tag 251 is present, such as when the sheet is shipped from the factory. The phase reference value is, for example, a value that differs for each image forming apparatus 10. Furthermore, the phase reference value is not limited to that obtained at the time of shipment from the factory. For example, the user may be prompted to control the system in a mode for obtaining the reference value, and the phase reference value may be obtained by switching to that mode in response to a user operation.

[0054] The identification unit 103 identifies the target wireless tag 251a based on the result of comparing the phase change amount detected by the detection unit 102 with the phase reference value stored in the reference value storage unit 222. Specifically, for example, the identification unit 103 compares the change pattern shown by the phase change amount detected by the detection unit 102 with the reference pattern stored in the reference value storage unit 222. If the comparison result shows that the phase change amount is substantially the same, the identification unit 103 identifies the wireless tag 251 that outputs the response wave with the phase as the target wireless tag 251a.

[0055] (Regarding Control of Wireless Tags 251 Not Being Read / Write Targets)

[0056] Furthermore, the identification unit 103 identifies a non-target wireless tag 251 (hereinafter referred to as a "non-target wireless tag 251b") that is not a target for reading or writing based on the phase change amount detected by the detection unit 102. The non-target wireless tag 251b is, for example, a wireless tag 251 attached to a sheet 250 in the paper feed cassettes 16a and 16b or the manual feed tray 16c (in the figure, the paper feed cassettes 16a and 16b).

[0057] The communication control unit 104 controls the non-target wireless tag 251b identified by the identification unit 103 to suppress the output of the response wave. Specifically, the communication control unit 104 controls the wireless tag communication device 201 to transmit a response suppression command to the non-target wireless tag 251b to suppress the output of the response wave. Upon receiving the response suppression command, the non-target wireless tag 251b sets a response suppression flag to enable, which suppresses the output of the response wave.

[0058] The response suppression flag is reset when the radio wave output from the wireless tag communication device 201 is cut off. Furthermore, the radio wave output from the wireless tag communication device 201 is cut off every time the sheet 250 is printed. Therefore, the response suppression flag is reset every time the sheet 250 is printed.

[0059] (Regarding the Position Where Information is Written to the Target Wireless Tag 251a)

[0060] Here, although the location for writing information to the target wireless tag 251a could be set on the first conveyor path 33a, in this embodiment, it is set on the second conveyor path 33b. This will be explained in detail below. In this embodiment, the conveyor path 33 includes the first conveyor path 33a, the second conveyor path 33b, and the third conveyor path 33c.

[0061] The first conveyance path 33a is a conveyance path 33 for forming an image on the sheet 250, and is, for example, a conveyance path 33 for front-side printing. The second conveyance path 33b is a conveyance path 33 for returning the sheet 250, after passing through the first conveyance path 33a, to the first conveyance path 33a. The second conveyance path 33b is, for example, a conveyance path 33 used for back-side printing. The second conveyance path 33b is a conveyance path 33 located closer to the wireless tag communication device 201 than the first conveyance path 33a.

[0062] The detection unit 102 detects the phase change of the response wave in the first conveyance path 33a. The identification unit 103 identifies the target wireless tag 251a based on the phase change of the response wave in the first conveyance path 33a detected by the detection unit 102. The communication control unit 104 controls the wireless tag communication device 201 so that information is written to the target wireless tag 251a when the target wireless tag 251a identified by the identification unit 103 moves along the second conveyance path 33b.

[0063] The communication control unit 103 also determines whether the sheet 250 with the target wireless tag 251a has moved onto the second conveyance path 33b. Specifically, the communication control unit 103 may determine that the sheet 250 with the target wireless tag 251a has moved onto the second conveyance path 33b based on the timing of switching the conveyance path 33 for the switchback, for example.

[0064] The sheet 250 that has moved to the second conveyance path 33b returns to the first conveyance path 33a. If the sheet is set to single-sided printing, back-side printing is not performed on the sheet that has returned to the first conveyance path 33a. However, if the sheet is set to back-side printing, back-side printing is performed.

[0065] (Example of Phase Data Stored in Phase Storage Unit 221)

[0066] Next, use Figure 4 An example of the phase data stored in the phase storage unit 221 will be described. Figure 4 : is an explanatory diagram showing an example of phase data stored in the phase storage unit 221. Figure 4 As shown, the phase data 400 is data including items of "index", "elapsed time", "tag ID", and "phase".

[0067] "Index" is information (number) that identifies each piece of data. "Elapsed time" is the time that has passed since the start of the printing operation, for example, the time that has passed since the wireless tag communication device 201 transmitted the first signal (carrier) during the printing operation. Furthermore, "Tag ID" is unique identification information assigned to each wireless tag 251. "Phase" indicates the phase (0 to 180 degrees).

[0068] In the phase data 400, two wireless tags 251 with "tag IDs" "AAAABBBB0001" and "CCCCDDDD0002" are shown. Figure 4 , two types of wireless tags 251 with "tag IDs" are present in the communication area. If three or more types of wireless tags 251 with "tag IDs" are present in the communication area, the phase data 400 stores the corresponding number of types of "tag IDs."

[0069] Next, we will describe the phase change of wireless tag 251 with tag ID "AAAABBBB0001." As indicated by "1" in the "Index," the phase of the response wave from wireless tag 251 with tag ID "AAAABBBB0001" at 0 msec is 20°. Furthermore, as indicated by "3" in the "Index," the phase of the response wave from wireless tag 251 with tag ID "AAAABBBB0001" at 10 msec is 40°. Therefore, the phase change of the response wave from wireless tag 251 with tag ID "AAAABBBB0001" from 0 msec to 10 msec is +20° (a 20° increment). This phase change is greater than a predetermined value (e.g., 10°).

[0070] As shown in "Index" "5," the phase of the response wave from wireless tag 251 with tag ID "AAAABBBB0001" at 20 msec is 60°. Therefore, the phase change from 10 msec to 20 msec for the response wave from wireless tag 251 with tag ID "AAAABBBB0001" is +20° (amount is 20°).

[0071] The phase change is greater than a predetermined value (e.g., 10°). This means that the wireless tag 251 is estimated to be the wireless tag 251 placed on the moving sheet 250. The comparison between the phase change and the predetermined value is, for example, an absolute value comparison. Furthermore, the phase change pattern obtained from the phase change matches, for example, a reference pattern stored in the reference value storage unit 222.

[0072] Thus, it is estimated that the sheet 250 provided with the wireless tag 251 having the tag ID “AAAABBBB0001” is moving in the conveyance path 33. Therefore, the identification unit 103 identifies the wireless tag 251 having the tag ID “AAAABBBB0001” as the target wireless tag 251a.

[0073] Next, we will describe the phase change of wireless tag 251 with tag ID "CCCCDDDD0002." As indicated by "2" in the "Index," the phase of the response wave from wireless tag 251 with tag ID "CCCCDDDD0002" at 1 msec is 162°. Furthermore, as indicated by "4" in the "Index," the phase of the response wave from wireless tag 251 with tag ID "CCCCDDDD0002" at 11 msec is 161°. Therefore, the phase change of the response wave from wireless tag 251 with tag ID "AAAABBBB0001" between 1 msec and 11 msec is -1° (1°). This phase change is less than a predetermined value (e.g., 10°).

[0074] Furthermore, as shown in "6" in the "Index," the "Phase" of wireless tag 251 with tag ID "CCCCDDDD0002" at 21 msec is 163 degrees. Therefore, the phase change of the response wave of wireless tag 251 with tag ID "AAAABBBB0001" between 11 msec and 21 msec is +2° (2°). This phase change is less than a predetermined value (e.g., 10°). Furthermore, the difference in phase change is due to an error. In other words, it can be considered that the phase change has barely changed.

[0075] Therefore, it is estimated that the sheet 250 to which the wireless tag 251 with tag ID "CCCCDDDD0002" is attached is not present on the conveyance path 33. Specifically, it is estimated that the sheet 250 to which the wireless tag 251 with tag ID "CCCCDDDD0002" is attached is located in any of the paper feed cassettes 16a, 16b, and the manual feed tray 16c. Therefore, the identification unit 103 identifies the wireless tag 251 with tag ID "CCCCDDDD0002" as a non-target wireless tag 251b.

[0076] (Regarding the Processing of Reading and Writing Information Between the Image Forming Apparatus 10 and the Wireless Tag 251)

[0077] Next, use Figure 5 An example of a process of reading and writing information between the image forming apparatus 10 (sheet conveying apparatus 50 ) and the wireless tag 251 will be described. Figure 5 This is a flowchart showing an example of a process of reading and writing information between the image forming apparatus 10 and the wireless tag 251 .

[0078] exist Figure 5 In the process, the image forming device 10 determines whether printing has started (ACT 501). The printing referred to here refers to, for example, printing a sheet 250. The image forming device 10 waits until printing starts (ACT 501: "No"). If printing has started (ACT 501: "Yes"), the image forming device 10 begins reading the RFID (ACT 502). Specifically, the image forming control unit 100 controls the wireless tag communication device 201 to start transmitting a signal (carrier wave) at regular intervals and to start receiving a response wave.

[0079] The image forming device 10 then determines whether the wireless tag 251 has been detected (ACT 503). Specifically, in ACT 503, the image forming control unit 100 determines whether the wireless tag communication device 201 has received a response wave from the wireless tag 251. If the wireless tag communication device 201 has not detected the wireless tag 251, the image forming device 10 enters standby mode (ACT 503: No). If the wireless tag communication device 201 has detected the wireless tag 251 (ACT 503: Yes), the image forming device 10 stores the various items of the phase data 400 ("elapsed time," "tag ID," and "phase") obtained by receiving the response wave from the wireless tag 251.

[0080] The image forming device 10 then detects the phase change of the wireless tag 251 indicated by the tag ID (ACT 505). The image forming device 10 then determines whether the magnitude of the phase change is greater than or equal to a predetermined value (ACT 506). If the magnitude of the phase change is greater than or equal to the predetermined value (ACT 506: "Yes"), the image forming device 10 proceeds to ACT 508. If the magnitude of the phase change is not greater than or equal to the predetermined value (ACT 506: "No"), the image forming device 10 controls the wireless tag communication device 201 to transmit a response suppression command to the wireless tag 251 (ACT 507), and then returns to ACT 503.

[0081] The image forming apparatus 10 then compares the phase change pattern obtained based on the phase change amount with the reference pattern stored in the reference value storage unit 222 (ACT 508). Next, the image forming apparatus 10 determines whether the phase change pattern matches the reference pattern (ACT 509). If the phase change pattern does not match the reference pattern (ACT 509: No), the image forming apparatus 10 returns to ACT 507.

[0082] If the phase change pattern matches the reference pattern (ACT 509: YES), the image forming apparatus 10 determines whether the sheet 250 having the wireless tag 251 indicated by the tag ID has passed through the second conveyance path 33b (ACT 510). This determination can be made by, for example, detecting that the sheet 250 has been diverted and conveyed to the second conveyance path 33b after passing through the branching portion 44b.

[0083] The image forming apparatus 10 waits until the sheet 250 passes through the second conveyance path 33b (ACT510: No). When the sheet 250 passes through the second conveyance path 33b (ACT510: Yes), the image forming apparatus 10 controls the wireless tag communication device 201 to write information to the wireless tag 251 (ACT511).

[0084] The image forming device 10 then determines whether printing has completed (ACT 512). The image forming device 10 waits until printing is completed (ACT 512: No). When printing is completed (ACT 512: Yes), the image forming device 10 controls the wireless tag communication device 201 to reset communication with the wireless tag 251 (ACT 513), thereby ending the series of processes.

[0085] Furthermore, by resetting the communication with the wireless tag 251, the output of the radio wave is reset, and the response suppression flag of the wireless tag 251 is also reset. Furthermore, by resetting the communication with the wireless tag 251, the phase data 400 is also reset.

[0086] In addition, Figure 5 In the flowchart shown, both the process of ACT 506 (determination of the amount of change) and the process of ACTs 508 and 509 (determination of the change pattern) are performed, but the present invention is not limited to this. For example, at least one of these processes may be performed.

[0087] According to the embodiment described above, the target wireless tag 251a can be identified based on the phase change of the response wave output from the wireless tag 251, and the wireless tag communication device 201 can be controlled to write information to the target wireless tag 251a. This allows the sheet conveyor 50 to appropriately write information to the wireless tags 251 attached to the sheets 250 traveling along the conveyance path 33. In other words, the sheet conveyor 50 can prevent erroneous writing of information to the wireless tags 251 attached to the sheets 250 located in the paper feed cassettes 16a, 16b, or the manual feed tray 16c.

[0088] Furthermore, in this embodiment, the sheet conveyor 50 identifies the target wireless tag 251a based on the result of comparing the phase change pattern of the response wave output from the wireless tag 251 with a reference pattern of the phase of the response wave when the sheet 250 moves on the conveyance path 33. This allows for more accurate estimation of the sheet 250 moving on the conveyance path 33, enabling more appropriate writing of information to the wireless tag 251 of the sheet 250 moving on the conveyance path 33.

[0089] Furthermore, in this embodiment, the sheet conveyor 50 identifies non-target wireless tags 251b based on the phase change of the response wave output from the wireless tag 251, and controls the non-target wireless tags 251b to suppress the output of the response wave. This prevents the output of response waves from wireless tags 251 that do not require a response. If the wireless tag communication device 201 receives a response wave from a wireless tag 251 that does not require a response, it reads the ID of the wireless tag 251 accordingly. In some cases, for example, the reading of the ID of the wireless tag 251 is performed at intervals longer than 10 msec.

[0090] According to this embodiment, the output of response waves from wireless tags 251 that do not require a response can be suppressed. This can prevent, for example, the reading of the ID of wireless tags 251 from occurring at intervals longer than 10 msec. In other words, the processing load associated with receiving response waves in the wireless tag communication device 201 can be reduced. Consequently, the phase change of the response wave can be appropriately detected, enabling more appropriate writing of information to wireless tags 251 on the sheet 250 moving along the conveyance path 33.

[0091] Furthermore, in this embodiment, the sheet conveyor 50 identifies the non-target wireless tag 251b based on the phase change of the response wave in the first conveyor path 33a and writes information to the wireless tag 251 of the sheet 250 when the sheet 250 has moved onto the second conveyor path 33b. This ensures a period during which the phase change of the response wave is detected on the first conveyor path 33a. In other words, the phase change of the response wave can be appropriately detected. Consequently, the sheet 250 moving on the conveyor path 33a can be estimated with greater accuracy. Furthermore, a period during which information is written to the wireless tag 251 on the second conveyor path 33b can be ensured. Consequently, information can be appropriately written to the wireless tag 251 of the sheet 250 moving on the second conveyor path 33b.

[0092] In this embodiment, the first conveyance path 33a is used as the conveyance path 33 for front-side printing, and the second conveyance path 33b is used as the conveyance path 33 for back-side printing. This allows efficient writing of information to the wireless tags 251 on the moving sheet 250 using the existing conveyance path 33, without requiring a separate conveyance path for reading and writing information from the wireless tags 251.

[0093] In this embodiment, the second conveyance path 33b is arranged closer to the wireless tag communication device 201 than the first conveyance path 33a. This shortens the communication distance with the wireless tag 251 in the second conveyance path 33b, allowing information to be written more appropriately to the wireless tag 251 on the sheet 250 moving on the second conveyance path 33b.

[0094] The function of the sheet conveying device 50 in the above-mentioned embodiment can also be realized by a computer. In this case, it can be realized by recording a program for realizing the function on a computer-readable recording medium and having the computer system read the program recorded in the recording medium and execute it. In addition, the "computer system" referred to here refers to hardware including an OS or peripheral devices. In addition, a "computer-readable recording medium" refers to a removable medium such as a floppy disk, a magneto-optical disk, a ROM, a CD-ROM, a storage device such as a hard disk built into the computer system. Furthermore, a "computer-readable recording medium" may also include a recording medium that dynamically stores a program for a short period of time, such as a communication line when sending a program via a network such as the Internet or a communication line such as a telephone line, or a recording medium that stores a program for a fixed period of time, such as a volatile memory inside a computer system that becomes a server or client in this case. In addition, the above-mentioned program can be a program for realizing a part of the aforementioned function, or a program that can be realized by combining the aforementioned function with a program already recorded in the computer system.

[0095] Although several embodiments of the present invention have been described, these embodiments are provided as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways and can be omitted, replaced, or modified without departing from the scope of the invention. These embodiments and their variations are included in the scope and spirit of the invention and are also included in the invention described in the claims and their equivalents.

Claims

1. A sheet conveying device, characterized in that: have: a conveying roller for conveying the sheet in a conveying path; A wireless tag communication device capable of receiving a response wave from a wireless tag placed on a sheet and writing information to the wireless tag; a detection unit configured to detect a change in phase of the response wave received by the wireless tag communication device; a determination unit that determines a target wireless tag to be read / written and a non-target wireless tag that is not a target wireless tag to be read / written based on the amount of change in the phase detected by the detection unit; as well as The control unit controls the wireless tag communication device to suppress output of the response wave for the non-target wireless tag identified by the identification unit, thereby writing information to the target wireless tag.

2. The sheet material conveying device according to claim 1, wherein: The sheet conveying device further includes a storage unit that stores in advance a reference value of the phase when the sheet moves on the conveying path. The identification unit identifies the target wireless tag based on a comparison result between the amount of change in the phase detected by the detection unit and the reference value stored in the storage unit.

3. The sheet material conveying device according to claim 1 or 2, characterized in that: The conveying path includes a first conveying path and a second conveying path, wherein the second conveying path is used to return the sheet after passing through the first conveying path to the first conveying path again. The detection unit detects the amount of change in the phase in the first transport path. The identification unit identifies the target wireless tag based on the amount of change in the phase in the first transport path detected by the detection unit. When the target wireless tag identified by the identification unit moves to the second transport path, the control unit controls the wireless tag communication device to write information to the wireless tag.

4. The sheet material conveying device according to claim 1, wherein: The conveying path includes a first conveying path and a second conveying path, wherein the second conveying path is used to return the sheet after passing through the first conveying path to the first conveying path again. The detection unit detects the amount of change in the phase in the first transport path. The identification unit identifies the target wireless tag based on the amount of change in the phase in the first transport path detected by the detection unit. When the target wireless tag identified by the identification unit moves to the second transport path, the control unit controls the wireless tag communication device to write information to the wireless tag.

5. The sheet material conveying device according to claim 3, wherein: The first conveying path is a conveying path for forming an image on a sheet. The second transport path is a transport path used when performing reverse printing.

6. The sheet material conveying device according to claim 4, wherein: The first conveying path is a conveying path for forming an image on a sheet. The second transport path is a transport path used when performing reverse printing.

7. The sheet material conveying device according to claim 3, wherein: The second conveyance path is a conveyance path arranged at a position closer to the wireless tag communication device than the first conveyance path.

8. The sheet material conveying device according to claim 4, wherein: The second conveyance path is a conveyance path arranged at a position closer to the wireless tag communication device than the first conveyance path.

9. A recording medium storing a program, wherein the recording medium is characterized in that: The program is for causing a computer of the sheet conveying device to execute the following processing: Detecting the phase change of the response wave received by the wireless tag communication device, Based on the detected phase change amount, a wireless tag to be read or written and a non-target wireless tag not to be read or written are determined; controlling the wireless tag communication device to suppress the output of the response wave from the determined non-target wireless tag, thereby writing information to the target wireless tag; The sheet material conveying device comprises: a conveying roller that conveys the sheet in the conveying path; and The wireless tag communication device can receive the response wave from the wireless tag provided on the sheet and write information to the wireless tag.

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