Wireless tag communication system

Abstract

To provide a wireless tag communication system capable of enhancing success rate of information writing to a wireless tag to be transported.SOLUTION: A wireless tag communication system includes: a transportation unit; a tag communication unit; and a control unit. The transportation unit transports sheets. The tag communication unit performs detection process for a wireless tag prepared for a sheet being transported, and information writing process to the wireless tag. After the transportation unit has started transportation of the sheet, the control unit allows the tag communication unit to perform the writing process after a predetermined time has elapsed.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] Embodiments of the present invention relate to a wireless tag communication system.

Background Art

[0002] There is an image forming apparatus capable of forming an image on a sheet provided with a wireless tag. Such an image forming apparatus includes a wireless tag communication device that communicates with the wireless tag. The wireless tag communication device may write information to the wireless tag during conveyance of the sheet. At this time, the wireless tag communication device needs to prevent accidentally writing information to a wireless tag that is not the writing target. To prevent such miswriting, a conventional wireless tag communication device, for example, sets the transmission power of a radio wave carrying a detection signal for detecting the wireless tag to be low. Then, the wireless tag communication device measures the RSSI (Received Signal Strength Indicator) of a radio wave (reflected wave) carrying a response signal returned from the wireless tag that has received the radio wave. The wireless tag communication device performs an information writing process on the wireless tag when the value of the RSSI exceeds a predetermined threshold. This threshold is set in advance so as to be a value that can distinguish between a wireless tag provided on a sheet being conveyed and a wireless tag provided on a sheet placed in a paper feed cassette (that is, a sheet before conveyance starts).

[0003] However, in the conveyance path of the sheet in the image forming apparatus, there may be a region where communication between the wireless tag communication device and the wireless tag is obstructed (hereinafter referred to as a "communication impossible region"). For example, a region where the deviation between the direction in which the wireless tag communication device emits a radio wave and the direction of the antenna of the wireless tag being conveyed becomes large is likely to be a communication impossible region. Also, when there is a region where radio waves are shielded due to members being densely arranged in the image forming apparatus, a communication impossible region is likely to occur. Therefore, when the sheet being conveyed is located in the communication impossible region, communication between the wireless tag and the wireless tag communication device may not be performed, and information writing to the wireless tag may fail.

Prior Art Documents

Patent Document

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem to be solved by the present invention is to provide a wireless tag communication system capable of increasing the success rate of writing information to a wireless tag being conveyed.

Means for Solving the Problems

[0006] The wireless tag communication system of the embodiment has a conveyance unit, a tag communication unit, and a control unit. The conveyance unit conveys a sheet. The tag communication unit performs detection processing of a wireless tag provided on the sheet being conveyed and writing processing of information to the wireless tag. The control unit causes the tag communication unit to execute the writing processing after a predetermined waiting time has elapsed after the conveyance unit starts conveying the sheet.

Brief Description of the Drawings

[0007]

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Best Mode for Carrying Out the Invention

[0008] Hereinafter, the wireless tag communication system of the present invention will be described with reference to the drawings. In the following description, components having the same or similar functions are denoted by the same reference numerals. Also, redundant descriptions may be omitted.

[0009] Hereinafter, the first embodiment will be described.

[0010] FIG. 1 is a side view of the image forming system according to the first embodiment. The image forming system is an example of the wireless tag communication system of the present invention. The image forming system is a system that forms an image on the surface of a sheet and writes information to a wireless tag provided on the sheet. The image forming system is installed and used in a workplace. As shown in FIG. 1, the image forming system includes an image forming apparatus 10 and a wireless tag communication apparatus 201.

[0011] The image forming apparatus 10 is an apparatus that forms an image on the surface of a conveyed sheet, such as an MFP (Multifunction Peripheral) or a printer. The image forming apparatus 10 includes a control panel 13, a printer unit 18, a paper discharge tray 20, and the like. The printer unit 18 includes a control unit 100, paper feed cassettes 161 to 164, and the like. The control unit 100 controls the operations of the control panel 13, the printer unit 18, and the like. Further, the control unit 100 controls the conveyance of the sheet in the printer unit 18. The control of the sheet conveyance is to control the conveyance timing of the sheet, the stop position of the sheet, the conveyance speed of the sheet, and the like.

[0012] The control panel 13 includes an input unit and a display unit (not shown). The input unit is, for example, an input button that receives a user's input operation. The display unit is, for example, a display that displays various information for the user to refer to. Note that the input unit and the display unit may be an integrated device such as a touch panel type display. The control panel 13 causes the display unit to display setting items related to the operation of the image forming apparatus 10. Further, the control panel 13 outputs information indicating the setting content selected by the user to the control unit 100.

[0013] The paper feed cassettes 161 to 164 store sheets provided with wireless tags. Note that the paper feed cassettes 161 to 164 can also store sheets that are not provided with wireless tags, of course. However, in the following description, the "sheet" shall refer to a sheet provided with a wireless tag. Generally, materials such as paper or plastic film are used for the sheet. However, as long as an image can be formed on the surface, any material may be used for the sheet.

[0014] The printer unit 18 performs image forming processing. The printer unit 18 forms an image based on the input image data on the surface of the sheet. The printer unit 18 includes an intermediate transfer belt 21. The intermediate transfer belt 21 is supported by rollers such as a driven roller 41 and a backup roller 40. The printer unit 18 rotates the intermediate transfer belt 21 in the direction of arrow m in FIG. 1 by rotating the rollers.

[0015] The printer unit 18 includes four sets of image forming stations 221 to 224. The image forming stations 221, 222, 223, and 224 are respectively used for forming images of Y (yellow), M (magenta), C (cyan), and K (black). The image forming stations 221 to 224 are arranged side by side along the intermediate transfer belt 21 on the lower side of the intermediate transfer belt 21. In the case of an image forming apparatus that forms only black-and-white images, it is sufficient to provide only the image forming station 224 that performs K (black) image formation.

[0016] Hereinafter, among the image forming stations 221 to 224, the configuration of the Y (yellow) image forming station 221 will be described as an example. Since the configurations of the image forming stations 222 to 224 are the same as that of the image forming station 221, detailed descriptions thereof will be omitted.

[0017] The image forming station 221 includes a charging charger 26, an exposure scanning head 27, a developing device 28, and a photoreceptor cleaner 29. The charging charger 26, the exposure scanning head 27, the developing device 28, and the photoreceptor cleaner 29 are arranged around a photoreceptor drum 24 that rotates in the direction of arrow n in FIG. 1.

[0018] The image forming station 221 includes a primary transfer roller 30. The primary transfer roller 30 faces the photoreceptor drum 24 via the intermediate transfer belt 21.

[0019] The image forming station 221 charges the photosensitive drum 24 with the charger 26 and then exposes it with the exposure scanning head 27. The image forming station 221 forms 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 formed by toner and carrier.

[0020] The primary transfer roller 30 primarily transfers the toner image formed on the photosensitive drum 24 to the intermediate transfer belt 21. The image forming stations 221 to 224 form a color toner image on the intermediate transfer belt 21 by the primary transfer roller 30. The color toner image is formed by sequentially overlapping toner images of Y (yellow), M (magenta), C (cyan), and K (black). The photosensitive cleaner 29 removes the toner remaining on the photosensitive drum 24 after the primary transfer.

[0021] The printer unit 18 includes a secondary transfer roller 32. The secondary transfer roller 32 faces the backup roller 40 via the intermediate transfer belt 21. The secondary transfer roller 32 secondarily transfers the color toner image on the intermediate transfer belt 21 to the sheet all at once. In the following description, when the term "toner image" is used, it may be either a color toner image or a toner image of only one color. Also, the toner image may be a toner image using decolorizing toner.

[0022] The sheet is conveyed along the conveyance paths 331 and 332. The conveyance path 331 is the conveyance path in the section from the confluence part 441 to the branching part 442. The conveyance path 331 is an example of a conveyance unit. The conveyance path 332 is the conveyance path in the section from the branching part 442 to the paper discharge tray 20.

[0023] The leading edge of the sheet taken out from the paper feed cassettes 161 to 164 or the manual feed tray 165 is abutted against the portion where the two registration rollers 31 that are stopped are in contact. The inclination of the sheet is corrected when it is abutted against the registration rollers 31. The control unit 100 starts the rotation of the registration rollers 31 in accordance with the position of the toner image on the rotating intermediate transfer belt 21 and moves the sheet to the position of the secondary transfer roller 32. The control unit 100 secondarily transfers the toner image formed on the intermediate transfer belt 21 to the sheet by the secondary transfer roller 32. The control unit 100 forms an image by conveying the sheet to the conveyance path 331 and fixing the toner image to the sheet by the fixing device 34. The control unit 100 discharges the sheet by conveying the sheet with the formed image to the conveyance path 332.

[0024] The wireless tag communication device 201 is, for example, an RFID (Radio Frequency Identification) reader / writer. The wireless tag communication device 201 includes a processor 218 and a storage device 219, which will be described later. The wireless tag communication device 201 is capable of communicating with the control unit 100. The wireless tag communication device 201 can communicate with the wireless tag provided on the sheet, read information from the wireless tag, or write information to the wireless tag. The wireless tag is, for example, an RFID tag.

[0025] The wireless tag communication device 201 executes a process of writing information to a wireless tag (hereinafter referred to as "tag writing process") before an image is formed on a sheet by the printer unit 18. However, the wireless tag communication device 201 may be configured to execute the tag writing process after an image is formed on a sheet by the printer unit 18. The wireless tag communication device 201 measures the RSSI of a radio wave (reflected wave) carrying a response signal transmitted from the wireless tag. The wireless tag communication device 201 determines whether or not to execute the tag writing process according to the measured RSSI value. For example, the wireless tag communication device 201 executes the tag writing process when the measured RSSI value is equal to or greater than a predetermined threshold. When the wireless tag communication device 201 executes the tag writing process, it starts the execution of the tag writing process at a timing based on a predetermined condition. Details of the tag writing process will be described in detail later.

[0026] Hereinafter, the functional configuration of the image forming apparatus 10 will be described.

[0027] FIG. 2 is a block diagram showing the functional configuration of the image forming apparatus 10 according to the first embodiment. As shown in FIG. 2, the image forming apparatus 10 includes a control unit 100, a control panel 13, a printer unit 18, and a wireless tag communication device 201.

[0028] The control unit 100 includes an arithmetic unit 51 and a storage device 52. The arithmetic unit 51 controls the control panel 13, the printer unit 18, and the wireless tag communication device 201 according to an image processing program stored in the storage device 52. The control unit 100 transmits information (hereinafter referred to as "tag writing instruction") for instructing the execution of the tag writing process to the wireless tag communication device 201, for example.

[0029] The arithmetic unit 51 is, for example, a processor such as a CPU (Central Processing Unit), or an ASIC (Application Specific Integrated Circuit). The storage device 52 is, for example, a storage medium such as a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination of these storage media.

[0030] The data receiving unit 53 receives image data indicating an image to be formed on a sheet from a host computer such as a PC (Personal Computer). The image data is, for example, data described in a page description language. The data receiving unit 53 stores the received image data in the storage device 52.

[0031] The image data expansion unit 54 determines image formation conditions based on the image data stored in the storage device 52. The image data expansion unit 54 expands the image data into data that can be used by the printer unit 18, such as raster data (hereinafter referred to as "image formation data"), based on the determined image formation conditions. The image data expansion unit 54 stores the expanded image formation data in the storage device 52.

[0032] The printer unit 18 includes a fixing device 34, a secondary transfer roller 32, and a developing device 28. The printer unit 18 forms an image on a sheet based on the image formation data stored in the storage device 52 by the image data expansion unit 54.

[0033] FIG. 3 is a diagram showing an example of positions where sheets can exist in the image forming apparatus 10 according to the first embodiment. Sheets Sa to Sd shown in FIG. 3 are sheets placed on the paper feed cassettes 161 to 164, respectively. Sheet Se is a sheet placed on the manual feed tray 165. That is, sheets Sa to Se are sheets before being conveyed. Sheet Sf is a sheet being conveyed on the conveyance path 331. Sheet Sg is a sheet placed on the paper discharge tray 20. That is, sheet Sg is a sheet after being conveyed.

[0034] As described above, a wireless tag is provided on the sheet. Also, the sheet to be subjected to the tag writing process is a sheet being conveyed on the conveyance path 331.

[0035] The wireless tag communication device 201 transmits a radio wave (carrier wave) carrying a detection signal for detecting the wireless tag in the direction of arrow k in FIG. 3. Electric power is generated in the antenna of the wireless tag that has received this radio wave. The wireless tag operates by this electric power and transmits a radio wave (reflected wave) carrying a response signal. The wireless tag communication device 201 receives the radio wave carrying the response signal. At this time, the RSSI of the radio wave carrying the response signal varies depending on the positional relationship between the wireless tag communication device 201 and the wireless tag, the directivity of the radio wave, etc. Since the sheet to be subjected to the tag writing process is being conveyed, the value of the RSSI of the radio wave received by the wireless tag communication device 201 changes with time.

[0036] As shown in FIG. 3, there is a communication impossible region e in the conveyance path 331. The communication impossible region e is a region where communication between the wireless tag communication device 201 and the wireless tag cannot be performed when the wireless tag is located in this communication impossible region e. In the communication impossible region e, the deviation between the direction in which the wireless tag communication device transmits the radio wave and the direction of the antenna of the wireless tag being conveyed becomes large, so the value of the RSSI significantly decreases. As a result, communication between the wireless tag communication device 201 and the wireless tag becomes difficult, and the tag writing process may fail. Note that the communication impossible region e may occur due to members densely arranged inside the image forming apparatus 10 blocking the radio wave.

[0037] In the case of the image forming apparatus 10 illustrated in FIG. 3, the sheets Sa and Se conveyed from the paper feed cassette 161 and the manual feed tray 165, respectively, do not pass through the non-communication area e. Therefore, in this case, a situation where communication between the wireless tag communication device 201 and the wireless tag becomes difficult does not occur.

[0038] When the image forming apparatus 10 starts conveying a sheet, it transmits a tag writing command to the wireless tag communication device 201. After that, since the sheet is being conveyed, in the case of the sheets Sb to Sd conveyed from the paper feed cassettes 162 to 164, respectively, the tag writing process needs to be performed after passing through the non-communication area e. Therefore, in the image forming system according to the first embodiment, the control unit 100 of the image forming apparatus 10 is configured to transmit a tag writing command to the wireless tag communication device 201 after a predetermined waiting time has elapsed after starting the conveyance of the sheet.

[0039] FIG. 4 is a diagram showing an example of the time-series change of the RSSI of the radio wave (reflected wave) with the response signal in the first embodiment. The vertical axis of the graph shown in FIG. 4 represents the RSSI value, and the horizontal axis represents time. In FIG. 4, the time period from the time origin to time t3 is the time period during which the wireless tag provided on the sheet approaches the wireless tag communication device 201. In FIG. 4, the time period after time t3 is the time period during which the wireless tag moves away from the wireless tag communication device 201. Therefore, at time t3, the RSSI value of the radio wave with the response signal becomes maximum. Also, the time period from time t1 to time t2 is the time period during which the wireless tag being conveyed passes through the non-communication area e. Therefore, during the time period from time t1 to time t2, the RSSI of the radio wave with the response signal significantly decreases.

[0040] Hereinafter, the configuration of the wireless tag communication device 201 will be described.

[0041] FIG. 5 is a diagram showing an example of the configuration of the wireless tag communication device 201 in the first embodiment. As shown in FIG. 5, the wireless tag communication device 201 includes an antenna 211, a circulator 212, a transmission amplifier 213, a modulation unit 214, a reception amplifier 215, a demodulation unit 216, and an interface 217.

[0042] The antenna 211 transmits, for example, a radio wave carrying a detection signal for detecting a wireless tag. The antenna 211 transmits a radio wave carrying a signal for writing information to the wireless tag (hereinafter referred to as a "tag writing signal"). Further, the antenna 211 receives a radio wave (reflected wave) carrying a response signal transmitted from the wireless tag. The antenna 211 is an example of a tag communication unit.

[0043] The control unit 220 includes a processor 218 such as a CPU (Central Processing Unit) and a storage device 219. The control unit 220 operates by the processor 218 reading a program stored in the storage device 219 and executing the read program. The control unit 220 controls the operations of each functional unit included in the wireless tag communication device 201.

[0044] The control unit 220 executes a tag writing process by controlling the operations of each functional unit included in the wireless tag communication device 201. The control unit 220 receives a tag writing command transmitted from the image forming apparatus 10. When the control unit 220 receives the tag writing command, it transmits a radio wave carrying a detection signal for detecting a wireless tag. The control unit 220 executes the tag writing process, for example, when the RSSI value of a radio wave (reflected wave) carrying a response signal transmitted from the wireless tag exceeds the threshold TH in FIG. 4. The threshold TH is stored in advance in the storage device 219.

[0045] The modulation unit 214 superimposes (modulates) a detection signal for the wireless tag communication device 201 to detect a wireless tag on a carrier wave. The modulated radio wave is radiated from the antenna 211. The transmission amplifier 213 amplifies the intensity of the signal transmitted by the wireless tag communication device 201. The circulator 212 separates the radio wave transmitted by the antenna 211 and the radio wave received by the antenna 211 (reflected wave). The reception amplifier 215 amplifies the intensity of the signal received by the antenna 211 to a predetermined intensity. The demodulation unit 216 demodulates the signal received by the antenna 211.

[0046] The interface 217 is an interface that communicatively connects the wireless tag communication device 201 and the image forming apparatus 10. Under the control of the control unit 220, the interface 217 receives a tag writing command transmitted from the image forming apparatus 10. Further, under the control of the control unit 220, the interface 217 transmits information indicating that the writing of information to the wireless tag has been completed (hereinafter referred to as "tag writing completion notification") to the image forming apparatus 10.

[0047] Hereinafter, the operation of the image forming system according to the first embodiment will be described.

[0048] FIG. 6 is a flowchart showing an example of the operation of the image forming system according to the first embodiment. First, the printer unit 18 of the image forming apparatus 10 acquires image forming data stored in the storage device 52 (ACT101). As described above, the image forming data is data that can be used by the printer unit 18 to form an image, such as raster data.

[0049] Next, the control panel 13 receives an input operation of the user for selecting a paper feed cassette to be used, and outputs information indicating the selected paper feed cassette to the control unit 100 (ACT102). The control unit 100 acquires the information indicating the selected paper feed cassette.

[0050] Next, the control unit 100 sets the tag proximity waiting time based on the selected paper feed cassette (ACT103). The "tag proximity waiting time" is a predetermined waiting time provided from when the conveyance of the sheet starts from the selected paper feed cassette until a tag writing command is sent to the wireless tag communication device 201. By providing the tag proximity waiting time, the tag writing process is executed after the conveyed sheet passes through the communication disabled area e.

[0051] For example, the tag proximity waiting time is set in advance so that the tag writing process is executed at the position where the leading edge of the sheet that has passed through the communication disabled area e abuts against the registration roller 31. This is because the wireless tag communication device 201 is installed near the registration roller 31 and the conveyance of the sheet temporarily stops when the leading edge of the sheet abuts against the registration roller 31, resulting in a higher success rate of the tag writing process.

[0052] The tag proximity waiting time is set according to the selected paper feed cassette. This is because the path lengths of the conveyance path 331 from each paper feed cassette to the position close to the wireless tag communication device 201 (hereinafter referred to as the "tag proximity position") are different. As described above, the tag proximity position is, for example, near the registration roller 31.

[0053] For example, as shown in FIG. 1, the path length of the conveyance path 331 from the uppermost paper feed cassette 161 to the tag proximity position is the shortest, and the path length of the conveyance path 331 from the lowermost paper feed cassette 164 to the tag proximity position is the longest. The tag proximity waiting time is set based on the time required for the sheet to be conveyed from when the conveyance of the sheet starts until it is conveyed to the tag proximity position. Therefore, for example, the tag proximity waiting time set when the paper feed cassette 161 is selected is shorter than the tag proximity waiting time set when the paper feed cassette 164 is selected.

[0054] FIG. 7 is a diagram showing an example of the tag proximity waiting time set in the image forming system according to the first embodiment. In FIG. 7, for each paper feed cassette, the path length (unit: millimeter), the conveyance speed (unit: millimeter per second), and the tag proximity waiting time (unit: second) are shown. As shown in FIG. 7, here, the conveyance speeds of the sheets conveyed from each paper feed cassette are all the same (200 millimeters per second). Therefore, the shorter the path length, the shorter the tag proximity waiting time, because the upper paper feed cassette has a shorter path length.

[0055] For example, the tag proximity waiting time T of the n-th paper feed cassette n_wait is calculated by the following formula (1).

[0056] T n_wait = L n / V n ···(1)

[0057] Here, L n represents the path length of the conveyance path 331 from the end (paper feed port) of the n-th paper feed cassette to the tag proximity position. Also, V n represents the conveyance speed of the sheet when using the n-th paper feed cassette. For example, the tag proximity waiting time T of the paper feed cassette 161 1_wait is calculated to be 0.5 [seconds] using the formula (1).

[0058] T 1_wait = L1 / V1 = 100 / 200 = 0.5

[0059] Note that the tag proximity waiting time may be set in consideration of the type and orientation of the sheet. For example, the position and orientation of the wireless tag provided on the sheet may vary depending on the type and orientation of the sheet. In this case, the optimal tag proximity waiting time varies depending on the type and orientation of the sheet.

[0060] FIG. 8 is a diagram showing an example of the type of sheet. For example, the longitudinal direction of the sheet in (a) is perpendicular to the conveyance direction, and the direction of the wireless tag is parallel to the conveyance direction. The longitudinal direction of the sheet in (b) is perpendicular to the conveyance direction, and the direction of the wireless tag is also perpendicular to the conveyance direction. The longitudinal direction of the sheet in (c) is parallel to the conveyance direction, and the direction of the wireless tag is also parallel to the conveyance direction. The longitudinal direction of the sheet in (d) is parallel to the conveyance direction, and the direction of the wireless tag is perpendicular to the conveyance direction. Since the optimal tag approaching waiting time varies depending on which of the sheets (a) to (d) it is, the tag approaching waiting time may be set in consideration of the type and orientation of the sheet.

[0061] In addition, differences in the type of sheet include, for example, sheet size (paper size), basis weight, wireless tag attachment position, etc. For example, the weight of the sheet is determined based on the sheet size and basis weight, and the upper limit of the conveyance speed of the sheet is determined based on that weight. Therefore, it is desirable to set the approaching waiting time in consideration of the type of sheet.

[0062] Returning to FIG. 6 for explanation again. Next, after setting the tag approaching waiting time, the control unit 100 starts the conveyance of the sheet (ACT104). Next, the control unit 100 waits for the set tag approaching waiting time to elapse (ACT105), and then transmits a tag writing command to the wireless tag communication device 201 (ACT106).

[0063] The interface 217 of the wireless tag communication device 201 receives the tag writing command transmitted from the image forming apparatus 10 and outputs the tag writing command to the control unit 220 (ACT201). Next, when the control unit 220 acquires the tag writing command, it starts the detection process of the wireless tag (ACT202).

[0064] Next, when the RSSI (Received Signal Strength) of the radio wave (reflected wave) carrying the response signal sent from the wireless tag exceeds a predetermined threshold (ACT203·YES), the control unit 220 executes tag writing processing on that wireless tag (ACT204). Next, when the tag writing processing is completed, the control unit 220 transmits a tag writing completion notification to the image forming apparatus 10 via the interface 217 (ACT205).

[0065] When the image forming apparatus 10 receives the tag writing completion notification transmitted from the wireless tag communication device 201 (ACT107), it executes image forming processing on the conveyed sheet (ACT108). Thus, the operation of the image forming system shown in the flowchart of FIG. 6 ends.

[0066] Note that the processes of transmitting and receiving the tag writing completion notification in ACT205 and ACT107 may be omitted.

[0067] As described above, in the image forming system according to the first embodiment, after starting the conveyance of the sheet, the image forming apparatus 10 waits for the tag approach waiting time to elapse and then transmits a tag writing command to the wireless tag communication device 201. By having such a configuration, the image forming system according to the first embodiment can execute the tag writing process after the conveyed sheet has passed through the non - communicable area e. Thereby, the image forming system can increase the success rate of writing information to the conveyed wireless tag.

[0068] Hereinafter, a modification of the first embodiment will be described.

[0069] In the image forming system according to the foregoing first embodiment, the image forming apparatus 10 was configured to transmit a tag writing command to the wireless tag communication apparatus 201 after waiting for the elapse of the tag approaching waiting time. That is, in the image forming system according to the first embodiment, the image forming apparatus 10 was configured to delay the start timing of the tag writing process. On the other hand, in the image forming system according to a modification of the first embodiment described below, the wireless tag communication apparatus has a configuration for delaying the start timing of the tag writing process.

[0070] In the following description, the image forming apparatus and the wireless tag communication apparatus according to the modification of the first embodiment are referred to as "image forming apparatus 10-1" and "wireless tag communication apparatus 201-1", respectively.

[0071] The operation of the image forming system according to the modification of the first embodiment will be described below.

[0072] FIG. 9 is a flowchart showing an example of the operation of the image forming system according to the modification of the first embodiment. First, the printer unit 18 of the image forming apparatus 10-1 acquires the image forming data stored in the storage device 52 (ACT111).

[0073] Next, the control panel 13 receives an input operation of the user for selecting the paper feed cassette to be used, and outputs information indicating the selected paper feed cassette to the control unit 100 (ACT112). The control unit 100 acquires the information indicating the selected paper feed cassette.

[0074] Next, the control unit 100 sets a tag approaching waiting time based on the selected paper feed cassette (ACT113). Next, after setting the tag approaching waiting time, the control unit 100 starts transporting the sheet (ACT114). Next, the control unit 100 transmits a tag writing command including information indicating the set tag approaching waiting time to the wireless tag communication apparatus 201 (ACT115).

[0075] The interface 217 of the wireless tag communication device 201-1 receives the tag writing command transmitted from the image forming apparatus 10-1, and outputs the tag writing command to the control unit 220 (ACT211). Next, when the control unit 220 acquires the tag writing command, it waits for the tag waiting time based on the information included in the tag writing command to elapse (ACT212), and then starts the detection process of the wireless tag (ACT213).

[0076] Next, when the RSSI (Received Signal Strength) of the radio wave (reflected wave) carrying the response signal transmitted from the wireless tag exceeds a predetermined threshold value (ACT214·YES), the control unit 220 executes the tag writing process on the wireless tag (ACT215). Next, when the tag writing process is completed, the control unit 220 transmits a tag writing completion notification to the image forming apparatus 10-1 via the interface 217 (ACT216).

[0077] When the image forming apparatus 10-1 receives the tag writing completion notification transmitted from the wireless tag communication device 201-1 (ACT116), it executes the image forming process on the conveyed sheet (ACT117). Thus, the operation of the image forming system shown in the flowchart of FIG. 9 ends.

[0078] Note that the processes of transmitting and receiving the tag writing completion notification in ACT216 and ACT116 may be omitted.

[0079] As described above, in the image forming system according to the modification of the first embodiment, after receiving the tag writing command, the wireless tag communication device 201-1 waits for the tag waiting time to elapse, and then starts the detection process of the wireless tag. By having such a configuration, the image forming system according to the modification of the first embodiment can execute the tag writing process after the conveyed sheet has passed through the non-communication area e. Thereby, the image forming system can increase the success rate of writing information to the conveyed wireless tag.

[0080] Hereinafter, a second embodiment will be described.

[0081] In the image forming system according to the modification of the first embodiment described above, the wireless tag communication device 201-1 starts the detection process of the wireless tag after waiting for the tag reception waiting time to elapse after receiving the tag writing command. On the other hand, in the image forming system according to the second embodiment described below, the wireless tag communication device performs a "tag re-detection process" of detecting the tag again after waiting for a predetermined waiting time (hereinafter referred to as "tag re-detection waiting time") to elapse after detecting the wireless tag by receiving the tag writing command. Then, when the wireless tag is detected again by the tag re-detection process, the wireless tag communication device executes the tag writing process.

[0082] That is, the tag re-detection waiting time is a predetermined waiting time provided between when a certain wireless tag is first detected by the tag detection process and when the tag re-detection process is executed. By providing the tag re-detection waiting time, the tag writing process is executed after the conveyed sheet passes through the non-communication area e. That is, the wireless tag communication device in the second embodiment has a configuration in which the wireless tag before passing through the non-communication area e is detected by the tag detection process, and the wireless tag after passing through the non-communication area e is re-detected by the tag re-detection process.

[0083] In the following description, the image forming apparatus and the wireless tag communication device in the second embodiment are referred to as "image forming apparatus 10-2" and "wireless tag communication device 201-2", respectively.

[0084] The operation of the image forming system according to the second embodiment will be described below.

[0085] FIG. 10 is a flowchart showing an example of the operation of the image forming system according to the second embodiment. First, the printer unit 18 of the image forming apparatus 10-2 acquires the image forming data stored in the storage device 52 (ACT121).

[0086] Next, the control panel 13 receives a user input operation for selecting a paper feed cassette to be used, and outputs information indicating the selected paper feed cassette to the control unit 100 (ACT122). The control unit 100 acquires the information indicating the selected paper feed cassette. Next, the control unit 100 sets a tag re-detection waiting time based on the selected paper feed cassette (ACT123).

[0087] The tag re-detection waiting time is set according to the selected paper feed cassette. This is because the path lengths of the conveyance path 331 from each paper feed cassette to the tag proximity position are different. As described above, the tag proximity position is, for example, in the vicinity of the registration roller 31.

[0088] FIG. 11 is a diagram showing an example of the tag re-detection waiting time set in the image forming system according to the second embodiment. In FIG. 11, the tag re-detection waiting time (unit: seconds) for each paper feed cassette is shown.

[0089] As shown in FIG. 1, the sheet Sa conveyed from the paper feed cassette 161 does not pass through the non-communication area e. Therefore, since it is not necessary to provide a tag detection waiting time for the paper feed cassette 161, the tag detection waiting time when the paper feed cassette 161 is used is 0 seconds. Here, it is assumed that the time T p required for the wireless tag to pass through the non-communication area e is 0.25 seconds (T p = 0.25). Therefore, the tag detection waiting time when the paper feed cassettes 162 to 164 are used is 0.25 seconds.

[0090] Note that the tag re-detection waiting time may be set in consideration of further factors such as the type and orientation of the sheet. For example, as shown in FIG. 8 described above, the position and orientation of the wireless tag provided on the sheet may vary depending on the type and orientation of the sheet. In this case, the optimal tag re-detection waiting time varies depending on the type and orientation of the sheet.

[0091] Returning to FIG. 10 for further explanation. Next, after setting the tag re-detection waiting time, the control unit 100 starts the conveyance of the sheet (ACT124). Next, the control unit 100 transmits a tag writing command including information indicating the set tag re-detection waiting time to the wireless tag communication device 201-2 (ACT125).

[0092] The interface 217 of the wireless tag communication device 201-2 receives the tag writing command transmitted from the image forming apparatus 10-2 and outputs the tag writing command to the control unit 220 (ACT221). Next, when the control unit 220 acquires the tag writing command, it starts the detection process of the wireless tag (ACT222). Next, when the RSSI (Received Signal Strength) of the radio wave (reflected wave) carrying the response signal sent from the wireless tag exceeds a predetermined threshold (ACT223·YES), the control unit 220 temporarily stops the tag detection process (ACT224).

[0093] Next, after waiting for the tag re-detection waiting time based on the information included in the tag writing command to elapse (ACT225), the control unit 220 starts the re-detection process of the wireless tag (ACT226). Next, when the RSSI (Received Signal Strength) of the radio wave (reflected wave) carrying the response signal sent from the wireless tag exceeds a predetermined threshold (ACT227·YES), the control unit 220 executes the tag writing process on the wireless tag (ACT228). Next, when the tag writing process is completed, the control unit 220 transmits a tag writing completion notification to the image forming apparatus 10-2 via the interface 217 (ACT229).

[0094] When the image forming apparatus 10-2 receives the tag writing completion notification transmitted from the wireless tag communication device 201-2 (ACT126), it executes the image forming process on the conveyed sheet (ACT127). Thus, the operation of the image forming system shown in the flowchart of FIG. 10 ends.

[0095] Incidentally, the processes of transmitting and receiving the tag writing completion notification for ACT229 and ACT126 may be omitted. Further, in the case of the second embodiment, the wireless tag communication device 201-2 does not need to start operating triggered by receiving a tag writing command transmitted from the image forming apparatus 10-2 by always performing tag detection processing. Therefore, in that case, the processes of transmitting and receiving the tag writing command for ACT125 and ACT221 can also be omitted. When both the transmission and reception of the tag writing command and the tag writing completion notification are omitted, the image forming apparatus 10-2 and the wireless tag communication device 201-2 do not need to communicate with each other. As a result, the wireless tag communication device 201-2 can be installed as an afterthought without modifying (retrofitting) an existing general-purpose image forming apparatus.

[0096] As described above, in the image forming system according to the second embodiment, after the wireless tag communication device 201-2 receives a tag writing command and detects a wireless tag, it performs tag re-detection processing after waiting for the tag re-detection waiting time to elapse. Then, when the wireless tag is detected again by the tag re-detection processing, the wireless tag communication device executes tag writing processing. By having such a configuration, the image forming system according to the second embodiment can execute tag writing processing after the conveyed sheet has passed through the non-communication area e. As a result, the image forming system can increase the success rate of writing information to the conveyed wireless tag.

[0097] Hereinafter, a third embodiment will be described.

[0098] In the image forming system according to the foregoing second embodiment, after the wireless tag communication device 201-2 receives a tag writing command and detects a wireless tag, it waits for the tag re-detection waiting time to elapse and then performs a tag re-detection process. Then, when a wireless tag is detected again by the tag re-detection process, the wireless tag communication device 201-2 is configured to execute a tag writing process. On the other hand, in the image forming system according to the third embodiment described below, after receiving a tag writing command, the wireless tag communication device repeatedly executes a wireless tag detection process. Then, when the number of times the same wireless tag is detected reaches a predetermined number of times (hereinafter referred to as the "tag detection count"), the wireless tag communication device executes a tag writing process.

[0099] The tag detection count is preset to a number of times that cannot be reached only before the sheet being conveyed passes through the non-communication area e. Therefore, by providing a threshold value for the tag detection count, the tag writing process is executed after the sheet being conveyed passes through the non-communication area e.

[0100] In the following description, the image forming apparatus and the wireless tag communication apparatus according to the third embodiment are referred to as "image forming apparatus 10-3" and "wireless tag communication apparatus 201-3", respectively.

[0101] The operation of the image forming system according to the third embodiment will be described below.

[0102] FIG. 12 is a flowchart showing an example of the operation of the image forming system according to the third embodiment. First, the printer unit 18 of the image forming apparatus 10-3 acquires image forming data stored in the storage device 52 (ACT131).

[0103] Next, the control panel 13 receives an input operation of the user for selecting a paper feed cassette to be used, and outputs information indicating the selected paper feed cassette to the control unit 100 (ACT132). The control unit 100 acquires the information indicating the selected paper feed cassette. Next, the control unit 100 sets a threshold value of the number of tag detections based on the selected paper feed cassette (ACT133).

[0104] The threshold value of the number of tag detections is set according to the selected paper feed cassette. This is because the path lengths of the conveyance path 331 from each paper feed cassette to the tag proximity position are different. As described above, the tag proximity position is, for example, in the vicinity of the registration roller 31.

[0105] FIG. 13 is a diagram showing an example of the number of tag detections set in the image forming system according to the third embodiment. FIG. 13 shows the threshold value of the number of tag detections for each paper feed cassette.

[0106] As shown in FIG. 1, the sheet Sa conveyed from the paper feed cassette 161 does not pass through the non-communication area e. Therefore, since it is not necessary to provide a threshold value for the number of tag detections for the paper feed cassette 161, the threshold value for the number of tag detections when the paper feed cassette 161 is used is 0 times. Here, the time T p required for the wireless tag to pass through the non-communication area e is assumed to be 0.25 seconds (T p = 0.25). Here, the time T d required for each tag detection process is assumed to be 0.05 seconds (T d = 0.05). Therefore, the threshold value for the number of tag detections when the paper feed cassettes 162 to 164 are used is 5 times (T p / T d = 5).

[0107] Returning to FIG. 12 and explaining again. Next, after setting the threshold value of the number of tag detections, the control unit 100 starts conveying the sheet (ACT134). Next, the control unit 100 transmits a tag writing command including the set threshold value of the number of tag detections to the wireless tag communication device 201-3 (ACT135).

[0108] The interface 217 of the wireless tag communication device 201-3 receives the tag writing command transmitted from the image forming apparatus 10-3, and outputs the tag writing command to the control unit 220 (ACT231). Next, when the control unit 220 acquires the tag writing command, it starts the detection process of the wireless tag (ACT232). Next, the control unit 220 initializes the value of the variable k to 0 and stores it in the storage device 219 (ACT233). The variable k is a variable used as a counter for the number of detections of the wireless tag.

[0109] Next, when the RSSI (Received Signal Strength) of the radio wave (reflected wave) carrying the response signal transmitted from the wireless tag does not exceed a predetermined threshold value (ACT234·No), the control unit 220 returns to the process of ACT233 and initializes the value of the variable k again. Also, when the RSSI (Received Signal Strength) of the radio wave (reflected wave) carrying the response signal transmitted from the wireless tag exceeds a predetermined threshold value (ACT234·Yes), the control unit 220 adds 1 to the value of the variable k (ACT235).

[0110] The control unit 220 repeats the tag detection process of ACT233 to ACT236 until the value of the variable k reaches the threshold value of the number of tag detections based on the information included in the tag writing command. When the value of the variable k reaches the threshold value of the number of tag detections based on the information included in the tag writing command (ACT236·Yes), the control unit 220 executes the tag writing process on the wireless tag (ACT237). Next, when the tag writing process is completed, the control unit 220 transmits a tag writing completion notification to the image forming apparatus 10-3 via the interface 217 (ACT238).

[0111] When the image forming apparatus 10-3 receives the tag writing completion notification transmitted from the wireless tag communication device 201-3 (ACT136), it executes the image forming process on the conveyed sheet (ACT137). Thus, the operation of the image forming system shown in the flowchart of FIG. 12 ends.

[0112] Note that the processes of transmitting and receiving the tag writing completion notification for ACT238 and ACT136 may be omitted. Further, similar to the second embodiment, in the case of the third embodiment, the wireless tag communication device 201-3 does not need to start operating triggered by receiving a tag writing command transmitted from the image forming apparatus 10-3 by always performing tag detection processing. Therefore, in that case, the processes of transmitting and receiving the tag writing command for ACT135 and ACT231 can also be omitted. When both the transmission and reception of the tag writing command and the tag writing completion notification are omitted, the image forming apparatus 10-3 and the wireless tag communication device 201-3 do not need to communicate with each other. As a result, the wireless tag communication device 201-3 can be installed as an aftermarket addition without modifying (retrofitting) an existing general-purpose image forming apparatus.

[0113] As described above, in the image forming system according to the third embodiment, after receiving a tag writing command and detecting a wireless tag, the wireless tag communication device 201-3 repeatedly executes the wireless tag detection process. Then, when the number of times the same wireless tag has been detected reaches the threshold value of the predetermined tag detection count, the wireless tag communication device 201-3 executes the tag writing process. By having such a configuration, the image forming system according to the third embodiment can execute the tag writing process after the conveyed sheet has passed through the communication disabled area e. Thereby, the image forming system can increase the success rate of writing information to the conveyed wireless tag.

[0114] Note that the above-described wireless tag communication devices 201, 201-1 to 201-3 may be installed and used in devices other than the image forming apparatus. That is, the wireless tag communication devices 201, 201-1 to 201-3 can be installed and used for any device as long as the device has a structure for conveying an object provided with a wireless tag.

[0115] According to the above-described embodiments, the wireless tag communication system includes a conveyance unit, a tag communication unit, and a control unit. For example, the wireless tag communication system is the image forming system in the embodiments, the conveyance unit is the conveyance path 331 in the embodiments, the tag communication unit is the antenna 211 in the embodiments, and the control unit is the control unit 220 in the embodiments. The conveyance unit conveys a sheet. The tag communication unit performs detection processing of a wireless tag provided on the sheet being conveyed and writing processing of information to the wireless tag. After the conveyance unit starts conveying the sheet, the control unit causes the tag communication unit to execute the writing processing after a predetermined waiting time has elapsed.

[0116] In the wireless tag communication system, the predetermined waiting time may be the time from when conveyance starts until detection processing starts. For example, the predetermined waiting time is the tag approach waiting time in the embodiments.

[0117] In the wireless tag communication system, the predetermined waiting time may be the time from when a wireless tag is detected by the detection processing until the writing processing is executed. For example, the predetermined waiting time is the tag redetection waiting time in the embodiments.

[0118] In the wireless tag communication system, the conveyance unit may have a plurality of conveyance paths with different path lengths. In this case, the predetermined waiting time is a time determined based on the path length. In this case, the control unit causes the writing processing to be executed after a predetermined waiting time corresponding to the conveyance path used for conveyance has elapsed.

[0119] Also, according to the above-described embodiment, the wireless tag communication system includes a conveyance unit, a tag communication unit, and a control unit. For example, the wireless tag communication system is an image forming system in the embodiment, the conveyance unit is the conveyance path 331 in the embodiment, the tag communication unit is the antenna 211 in the embodiment, and the control unit is the control unit 220 in the embodiment. The conveyance unit conveys the sheet. The tag communication unit performs detection processing of a wireless tag provided on the sheet being conveyed and writing processing of information to the wireless tag. After the conveyance unit starts conveying the sheet, the control unit repeatedly executes the detection processing on the tag communication unit, and when the same wireless tag is detected continuously a predetermined number of times, the control unit causes the tag communication unit to execute the writing processing. For example, the predetermined number of times is the threshold value of the tag detection times in the embodiment.

[0120] At least a part of the functions of the image forming apparatus 10 and the wireless tag communication apparatus 201 in the above-described embodiment may be realized by a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the "computer system" shall include hardware such as an OS and peripheral devices. Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or the like, and a storage device such as a hard disk incorporated in a computer system. Furthermore, the "computer-readable recording medium" also includes something that holds a program dynamically for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and something that holds a program for a certain time like a volatile memory inside a computer system that becomes a server or a client in that case. Also, the above program may be for realizing a part of the above-described functions, and may further be realized in combination with a program already recorded in the computer system for realizing the above-described functions.

[0121] Although some embodiments of the present invention have been described, these embodiments are merely examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, as well as in the invention described in the claims and the equivalent scope thereof.

[0122] The following discloses the appendices according to the above-described embodiments.

[0123] (Appendix 1) A transport unit that transports a sheet, A tag communication unit that performs detection processing of a wireless tag provided on the sheet during transport and writing processing of information to the wireless tag, A control unit that causes the tag communication unit to execute the writing process after a predetermined waiting time has elapsed after the transport unit starts transporting the sheet. A wireless tag communication system comprising: (Appendix 2) The predetermined waiting time is the time from when the transport starts until the detection process starts. The wireless tag communication system according to Appendix 1. (Appendix 3) The predetermined waiting time is the time from when the wireless tag is detected by the detection process until the writing process is executed. The wireless tag communication system according to Appendix 1. (Appendix 4) The transport unit has a plurality of transport paths with different path lengths, The predetermined waiting time is a time determined based on the path length, The control unit causes the writing process to be executed after the predetermined waiting time corresponding to the transport path used for the transport has elapsed. The wireless tag communication system according to any one of Appendices 1 to 3. (Appendix 5) The predetermined waiting time is a time determined in advance based on at least one of the path length of the conveyance path of the conveyance unit, the conveyance speed of the sheet by the conveyance unit, the installation position of the wireless tag on the sheet, the installation direction of the wireless tag on the sheet, the conveyance direction of the sheet, and the weight of the sheet. The wireless tag communication system according to any one of Appendices 1 to 4. (Appendix 6) Resist roller further comprising The predetermined waiting time is a time determined in advance so that the sheet is located in the vicinity of the resist roller at the end point of the predetermined waiting time. The wireless tag communication system according to any one of Appendices 1 to 5. (Appendix 7) A conveyance unit that conveys a sheet, A tag communication unit that performs detection processing of a wireless tag provided on the sheet being conveyed and writing processing of information to the wireless tag, After the conveyance unit starts conveying the sheet, the tag communication unit is repeatedly made to execute the detection processing, and when the same wireless tag is detected continuously a predetermined number of times, the tag communication unit is made to execute the writing processing. A control unit A wireless tag communication system comprising (Appendix 8) The conveyance unit has a plurality of conveyance paths with different path lengths, The predetermined number of times is a number determined based on the path length, When the same wireless tag is detected continuously the predetermined number of times corresponding to the conveyance path used for the conveyance, the control unit executes the writing processing. The wireless tag communication system according to Appendix 7. (Appendix 9) The predetermined number of times is a number determined in advance based on at least one of the path length of the conveyance path of the conveyance unit, the conveyance speed of the sheet by the conveyance unit, the installation position of the wireless tag on the sheet, the installation direction of the wireless tag on the sheet, the conveyance direction of the sheet, and the weight of the sheet. The wireless tag communication system according to Supplementary Note 7 or 8. (Supplementary Note 10) Resist roller further comprising the predetermined waiting time is a time predetermined so that at the end of the predetermined waiting time, the sheet is located in the vicinity of the resist roller The wireless tag communication system according to any one of Supplementary Notes 7 to 9. (Supplementary Note 11) When the received signal strength of the reflected wave transmitted from the wireless tag is equal to or greater than a predetermined threshold value, the tag communication unit recognizes that the wireless tag has been detected. The wireless tag communication system according to any one of Supplementary Notes 1 to 10.

[0124] (Supplementary Note 12) A tag communication unit that performs detection processing of a wireless tag provided on the sheet being conveyed by a conveyance unit of an image forming apparatus that conveys the sheet, and writing processing of information to the wireless tag; A control unit that causes the tag communication unit to execute the writing process after a predetermined waiting time has elapsed after the conveyance unit starts conveying the sheet; A wireless tag communication device comprising: (Supplementary Note 13) The predetermined waiting time is the time from when the conveyance starts until the detection process starts. The wireless tag communication device according to Supplementary Note 12. (Supplementary Note 14) The predetermined waiting time is the time from when the wireless tag is detected by the detection process until the writing process is executed. The wireless tag communication device according to Supplementary Note 12. (Supplementary Note 15) The conveyance unit has a plurality of conveyance paths with different path lengths, the predetermined waiting time is a time determined based on the path length, the control unit causes the writing process to be executed after the predetermined waiting time corresponding to the conveyance path used for the conveyance has elapsed The wireless tag communication device according to any one of Appendices 12 to 14. (Appendix 16) The predetermined waiting time is a time determined in advance based on at least one of the path length of the conveyance path of the conveyance unit, the conveyance speed of the sheet by the conveyance unit, the installation position of the wireless tag on the sheet, the installation direction of the wireless tag on the sheet, the conveyance direction of the sheet, and the weight of the sheet. The wireless tag communication device according to any one of Appendices 12 to 15. (Appendix 17) The predetermined waiting time is a time determined in advance so that the sheet is located in the vicinity of the registration roller at the end point of the predetermined waiting time. The wireless tag communication device according to any one of Appendices 12 to 16. (Appendix 18) A tag communication unit that performs detection processing of a wireless tag provided on the sheet being conveyed by a conveyance unit of an image forming apparatus that conveys the sheet, and writing processing of information to the wireless tag; A control unit that repeatedly executes the detection processing on the tag communication unit after the conveyance unit starts conveying the sheet, and causes the tag communication unit to execute the writing processing when the same wireless tag is detected continuously a predetermined number of times; A wireless tag communication device comprising: (Appendix 19) The conveyance unit has a plurality of conveyance paths with different path lengths, The predetermined number of times is a number determined based on the path length, The control unit causes the writing processing to be executed when the same wireless tag is detected continuously the predetermined number of times corresponding to the conveyance path used for the conveyance. The wireless tag communication device according to Appendix 18. (Appendix 20) The predetermined number of times is a number predetermined based on at least one of the path length of the conveyance path of the conveyance unit, the conveyance speed of the sheet by the conveyance unit, the installation position of the wireless tag on the sheet, the installation direction of the wireless tag on the sheet, the conveyance direction of the sheet, and the weight of the sheet. The wireless tag communication device according to appended note 18 or 19. (Appended note 21) The predetermined waiting time is a time predetermined so that the sheet is located in the vicinity of the registration roller of the image forming apparatus at the end point of the predetermined waiting time. The wireless tag communication device according to any one of appended notes 18 to 20. (Appended note 22) When the reception signal strength of the reflected wave transmitted from the wireless tag is equal to or greater than a predetermined threshold value, the tag communication unit recognizes that the wireless tag has been detected. The wireless tag communication device according to any one of appended notes 12 to 21.

[0125] (Appended note 23) A conveyance unit that conveys a sheet, A tag communication unit that performs detection processing of a wireless tag provided on the sheet being conveyed and writing processing of information to the wireless tag, A control unit that causes the tag communication unit to execute the writing process after a predetermined waiting time has elapsed after the conveyance unit starts conveying the sheet, An image forming apparatus comprising: (Appended note 24) The predetermined waiting time is the time from when the conveyance starts until the detection process starts. The image forming apparatus according to appended note 23. (Appended note 25) The predetermined waiting time is the time from when the wireless tag is detected by the detection process until the writing process is executed. The image forming apparatus according to appended note 1. (Appended note 26) The conveyance unit has a plurality of conveyance paths with different path lengths, The predetermined waiting time is a time determined based on the path length. The control unit causes the writing process to be executed after the predetermined waiting time corresponding to the transport path used for the transport has elapsed. The image forming apparatus according to any one of Appendices 23 to 25. (Appendix 27) The predetermined waiting time is a time predetermined based on at least one of the path length of the transport path of the transport unit, the transport speed of the sheet by the transport unit, the installation position of the wireless tag on the sheet, the installation direction of the wireless tag on the sheet, the transport direction of the sheet, and the weight of the sheet. The image forming apparatus according to any one of Appendices 23 to 26. (Appendix 28) Registration roller further includes The predetermined waiting time is a time predetermined so that the sheet is located near the registration roller at the end point of the predetermined waiting time. The image forming apparatus according to any one of Appendices 23 to 27. (Appendix 29) A transport unit that transports a sheet, A tag communication unit that performs detection processing of a wireless tag provided on the sheet being transported and writing processing of information to the wireless tag, After the transport unit starts transporting the sheet, the tag communication unit is repeatedly caused to execute the detection process, and when the same wireless tag is detected continuously a predetermined number of times, the tag communication unit is caused to execute the writing process. A control unit, An image forming apparatus comprising: (Appendix 30) The transport unit has a plurality of transport paths with different path lengths, The predetermined number of times is a number determined based on the path length, When the same wireless tag is detected continuously the predetermined number of times corresponding to the transport path used for the transport, the control unit causes the writing process to be executed. The image forming apparatus according to Appendix 29. (Appendix 31) The predetermined number of times is a number predetermined based on at least one of the path length of the conveyance path of the conveyance unit, the conveyance speed of the sheet by the conveyance unit, the installation position of the wireless tag on the sheet, the installation direction of the wireless tag on the sheet, the conveyance direction of the sheet, and the weight of the sheet. The image forming apparatus according to Appendix 29 or 30. (Appendix 32) Registration roller further comprising The predetermined waiting time is a time predetermined so that the sheet is located in the vicinity of the registration roller at the end point of the predetermined waiting time. The image forming apparatus according to any one of Appendices 29 to 31. (Appendix 33) When the reception signal strength of the reflected wave transmitted from the wireless tag by the tag communication unit is equal to or greater than a predetermined threshold value, the wireless tag is recognized as having been detected. The image forming apparatus according to any one of Appendices 23 to 32.

[0126] (Appendix 34) A wireless tag communication method by a computer, comprising performing a detection process of a wireless tag provided on the sheet being conveyed by a conveyance unit that conveys the sheet, and a writing process of information to the wireless tag; after the conveyance unit starts conveying the sheet, causing the tag communication unit to execute the writing process after a predetermined waiting time has elapsed. Wireless tag communication method. (Appendix 35) A wireless tag communication method by a computer, comprising performing a detection process of a wireless tag provided on the sheet being conveyed by a conveyance unit that conveys the sheet, and a writing process of information to the wireless tag; After the conveyance unit starts the conveyance of the sheet, the tag communication unit is repeatedly made to execute the detection process, and when the same wireless tag is detected continuously a predetermined number of times, the tag communication unit is made to execute the writing process Wireless tag communication method

[0127] (Appendix 36) To a computer A tag communication step of performing a detection process of a wireless tag provided on the sheet being conveyed by a conveyance unit that conveys the sheet, and a writing process of information to the wireless tag, A control step of, after the conveyance unit starts the conveyance of the sheet, making the tag communication unit execute the writing process after a predetermined waiting time has elapsed A program for causing the above to be executed (Appendix 37) To a computer A tag communication step of performing a detection process of a wireless tag provided on the sheet being conveyed by a conveyance unit that conveys the sheet, and a writing process of information to the wireless tag, A control step of, after the conveyance unit starts the conveyance of the sheet, repeatedly making the tag communication unit execute the detection process, and when the same wireless tag is detected continuously a predetermined number of times, making the tag communication unit execute the writing process A program for causing the above to be executed

Explanation of reference numerals

[0128] 10,10-1 to 10-3… Image forming apparatus, 13… Control panel, 18… Printer unit, 20… Paper discharge tray, 21… Intermediate transfer belt, 24… Photoconductor drum, 26… Charger, 27… Exposure scanning head, 28… Developing device, 29… Photoconductor cleaner, 30… Primary transfer roller, 31… Registration roller, 32… Secondary transfer roller, 34… Fixing device, 40… Backup roller, 41… Driven roller, 51… Arithmetic unit, 52… Storage device, 53… Data receiving unit, 54… Image data expansion unit, 100… Control unit, 161 to 164… Paper feed cassette, 165… Tray, 201, 201-1 to 201-3… Wireless tag communication device, 211… Antenna, 212… Circulator, 213… Transmitting amplifier, 214… Modulation unit, 215… Receiving amplifier, 216… Demodulation unit, 217… Interface, 218… Processor, 219… Storage device, 220… Control unit, 221 to 224… Image forming station, 331… Conveyor path, 332… Conveyor path, 441… Merging section, 442… Branching section

Claims

1. A conveying unit that conveys a sheet, A tag communication unit that performs detection processing of a wireless tag provided on the sheet being conveyed and writing processing of information to the wireless tag, A control unit that causes the tag communication unit to execute the writing process after a predetermined waiting time has elapsed after the conveying unit starts conveying the sheet, A wireless tag communication system comprising:

2. The predetermined waiting time is the time from when the conveyance starts until the detection process starts. The wireless tag communication system according to Claim 1.

3. The predetermined waiting time is the time from when the wireless tag is detected by the detection process until the writing process is executed. The wireless tag communication system according to Claim 1.

4. The conveying unit has a plurality of conveying paths with different path lengths, The predetermined waiting time is a time determined based on the path length, The control unit causes the writing process to be executed after the predetermined waiting time corresponding to the conveying path used for the conveyance has elapsed. The wireless tag communication system according to any one of Claims 1 to 3.

5. A conveying unit that conveys a sheet, A tag communication unit that performs detection processing of a wireless tag provided on the sheet being conveyed and writing processing of information to the wireless tag, A control unit that repeatedly executes the detection process on the tag communication unit after the conveying unit starts conveying the sheet, and causes the tag communication unit to execute the writing process when the same wireless tag is detected continuously a predetermined number of times. A wireless tag communication system comprising:

Images