Postal matter ejection apparatus with gap setting unit according to postal matter thickness

A postal matter ejection apparatus includes an ejection unit, a thickness detection unit, a thickness storage unit, a detection unit, an acquisition unit, a setting unit, and an adjustment unit. The ejection unit ejects a postal matter. The thickness detection unit measures a thickness of the postal matter. The thickness storage unit stores thickness information. The acquisition unit acquires a thickness of a preceding postal matter. The setting unit sets a gap between the preceding postal matter and the postal matter ejected by the ejection unit in accordance with the thickness of the preceding postal matter. The adjustment unit adjusts timing for supplying the postal matter to a conveyance path in accordance with the gap.

FIELD

Embodiments described herein relate generally to a sheet ejection apparatus and a sheet processing apparatus.

BACKGROUND

For example, a sheet processing apparatus such as a mail sorting apparatus comprises a sheet ejection apparatus configured to eject sheets such as postal matters which are processing targets. Much of the sheet processing apparatuses process the sheets ejected by the sheet ejection apparatus while conveying them. However, the sheets having different thicknesses cannot be often conveyed at the same speed, even if a conveying mechanism operates at a constant speed. For example, when the thicknesses of the sheets increase, a conveying speed tends to be slow. If the conveying speed of each sheet is not constant, gaps between preceding and following sheets conveyed in the sheet processing apparatus vary. When the following sheet catches up the preceding sheet, the sheet processing apparatus cannot normally process the sheets, and hence the apparatus discharges both the following sheet and the preceding sheet.

DETAILED DESCRIPTION

In general, according to one embodiment, a sheet ejection apparatus includes an ejection unit, a thickness detection unit, a thickness storage unit, a sheet detection unit, an acquisition unit, a setting unit, and an adjustment unit. The ejection unit ejects a sheet that is to be conveyed to a conveyance path. The thickness detection unit measures a thickness of the sheet ejected by the ejection unit. The thickness storage unit stores thickness information detected by the thickness detection unit. The sheet detection unit detects the sheet ejected by the ejection unit. The acquisition unit acquires from the thickness storage unit a thickness of a preceding sheet conveyed to the conveyance path prior to the sheet ejected by the ejection unit. The setting unit sets a gap between the preceding sheet and the sheet ejected by the ejection unit in accordance with the thickness of the preceding sheet acquired by the acquisition unit. The adjustment unit adjusts timing for supplying the sheet detected by the sheet detection unit to the conveyance path in accordance with the gap set by the setting unit.

An embodiment will be described hereinafter with reference to the drawings.

A sheet processing apparatus according to this embodiment is configured to process respective sheets wile sequentially conveying the sheets. For example, as the sheet processing apparatus, assumed is a mail sorting device or the like that sorts postal matters (postcards, sealed matters, and others) as sheets in accordance with destination information (sorting information), e.g., an address or a postal code and accumulates the sorted sheets. Further, the sheet processing apparatus according to this embodiment comprises an ejection unit as a sheet ejection apparatus that ejects a sheet as a processing target from a supply unit and conveys it to a conveyance path in the sheet processing apparatus. For example, the sheet ejection apparatus according to this embodiment can be used as an ejection unit that ejects a postal matter which is a processing target in the mail sorting device.

Furthermore, the mail sorting device as an example of the sheet processing apparatus carries out the following processing as processing for postal matters as sheets. The mail sorting device ejects postal matters one by one and sequentially conveys the postal matters. The mail sorting device reads an image on each postal matter to be conveyed by using a scanner and recognizes destination information such as an address and a postal code from the read image of each sheet. The mail sorting device associates stackers provided in an accumulation unit with various kinds of destination information (sorting information for delivery) in advance and decides a stacker as a sorting destination of each postal matter based on recognition result of the destination information for the read image of each postal matter. The mail sorting device conveys each sheet to the stacker decided as the sorting destination and accumulates it.

Each ofFIG. 1AandFIG. 1Bshows a structural example of a sheet processing apparatus1according to an embodiment.FIG. 1Ashows a structural example of various modules in the sheet processing apparatus1.FIG. 1Bshows a structural example of appearance when the sheet processing apparatus1depicted inFIG. 1Ais shown from its side surface. As the sheet processing apparatus1shown inFIG. 1AandFIG. 1B, assumed is a mail sorting device that sorts each postal matter (e.g., a letter or a sealed matter) as a sheet based on sorting information as destination information, e.g., an address and postal code.

In the structural example shown inFIG. 1A, the sheet processing apparatus1comprises processing modules such as an operation panel10, a supply unit11, an ejection unit12, a conveyance unit (conveyance path)13, a discharge unit14, a pre-barcode read unit15, a character recognition unit16, a print unit17, a verify barcode read unit18, a branch unit, and an accumulation unit20. Additionally, the sheet processing apparatus1has a control system comprising control units that control operations of the respective modules and a control unit that integrally controls the control units of the respective modules. It is to be noted that a structural example of the control system will be described later.

The operation panel10functions as a user interface. The operation panel10has, e.g., an operation unit and a display unit. The operation panel10is constituted of, e.g., a display device having a built-in touch panel as the operation unit. Further, the operation panel10may be constituted of a keyboard as the operation unit and a display device as the display unit.

The operation panel10as the operation unit accepts input of various operations performed by an operator. The operation panel10transmits a signal indicative of input operation contents to the control unit. The operation panel10as the display unit displays a screen generated by the control unit. For example, the operation panel10displays various kinds of operation guidance, processing results, and others to the operator.

The supply unit11stocks the sheets as processing targets. The supply unit11is set while having the sheets as sorting processing targets overlapping therein. As each sheet that is a sorting processing target, assumed is a sheet having a character string indicative of a sorting destination written on a first surface thereof. For example, the character string representing a sorting destination may be a character string representing a destination such as an address or a postal code. For example, the sheets are set in the supply unit11with their trailing ends being trued up in such a manner that the first surfaces face the same direction. The supply unit11sequentially supplies the sheets to the ejection unit12installed at an ejecting position.

The ejection unit12ejects the sheets set in the supply unit11one by one at predetermined gaps. The ejection unit12functions as a sheet ejection apparatus that ejects postal matters as the sheets which are processing targets. The ejection unit12supplies the sheets ejected from the supply unit11to a conveyance path of the conveyance unit13. The ejection unit12has a later-described ejection roller, a delivery roller, various sensors, and others. For example, when the ejection roller installed in contact with a sheet placed at an end portion (the ejecting position) of the supply unit11rotates, the ejection unit12ejects the sheets set in the supply unit11one by one from the end portion of the supply unit11. The ejection unit12delivers the sheets ejected by the ejection roller to the conveyance unit13by using the delivery roller. A structural example of the ejection unit12will be described later in detail.

The conveyance unit13has a conveyance path along which the sheets are conveyed to the respective units in the sheet processing apparatus1. The conveyance path as the conveyance unit13is constituted of conveyance mechanisms, e.g., a conveyance roller, a conveyance belt, and a drive pulley. The drive pulley is driven by a drive motor, and the conveyance belt is operated by the drive pulley. The conveyance unit13conveys the sheets ejected by the ejection unit12by operating the conveyance path constituted of the conveyance mechanism, e.g., the conveyance belt at a constant speed. Furthermore, sensors and gates are set respective positions on the conveyance path in the sheet processing apparatus1. A control system of the sheet processing apparatus1sequentially controls the gates or the like in accordance with a processing result of each module and controls conveyance of the sheets using the conveyance path.

The discharge unit14is provided on the conveyance unit13. The discharge unit14detects and discharges each sheet which cannot be subjected to subsequent processing. For example, the discharge unit14judges whether the subsequent processing can be performed with respect to each sheet. The discharge unit14comprises a non-illustrated discharge and accumulation unit. The discharge and accumulation unit accumulates sheets which have been determined to be inappropriate for the subsequent processing (sheets determined to be discharged).

The discharge unit14has a length detection unit, a thickness detection unit, and a hardness detection unit. The length detection unit detects a length of each sheet in a conveyance direction. The discharge unit14detects each sheet whose length is outside the scope of specifications (which cannot be processed) by using the length detection unit. The thickness detection unit detects a thickness of each sheet. The discharge unit14detects each sheet whose thickness is outside the scope of specifications (which cannot be processed) by using the thickness detection unit. The hardness detection unit detects hardness of each sheet. The discharge unit14detects each sheet whose hardness is outside the scope of specifications (which cannot be processed) by using the hardness detection unit. The discharge unit14discharges each sheet whose length, thickness, or hardness has been detected as being outside the scope of specification.

Furthermore, the discharge unit14has a foreign substance detection unit, a metal detection unit, a state detection unit, and an overlap detection unit. The foreign substance detection unit detects each sheet containing a foreign substance that may possibly cause inconveniences in subsequent processing. The metal detection unit detects each sheet containing a metal that may possibly cause inconveniences in subsequent processing. The state detection unit detects each sheet which has a shape and a conveyance state that may possibly cause inconveniences in subsequent processing. The overlap detection unit detects sheets that are conveyed in overlapping state.

The discharge unit14discharges each sheet from which a foreign substance has been detected by the foreign substance detection unit, each sheet from which a metal has been detected by the metal detection unit, each sheet which has been detected to have a non-standard shape by the state detection unit, each sheet which has been detected to be in an abnormal conveyance state by the state detection unit, or each sheet which has been detected to be in an overlapping state by the overlap detection unit.

The pre-barcode read unit15reads a barcode previously given to each sheet that is conveyed on the conveyance path. The pre-barcode read unit15converts the read barcode into information indicative of a sorting destination. The pre-barcode read unit15transmits the information indicative of the sorting destination obtained from the read barcode (sorting information) to the control unit. The control unit determines a conveyance destination of the sheet based on the sorting information received from the pre-barcode read unit. The control unit controls each unit to accumulate the sheet on the determined conveyance destination.

The character recognition unit16recognizes characters written on the first surface of the sheet conveyed on the conveyance path. The character recognition unit16reads an image on the first surface of the sheet by using a scanner and recognizes characters from the image read by the scanner. The character recognition unit16transmits a character recognition result including the sorting information of the sheet to the control unit. The control unit generates the sorting information based on the character recognition result received from the character recognition unit16and determines a sorting destination associated with the sorting information.

For example, it is assumed that the sheet is a postal matter having characters representing a destination such as an address or a postal code written on the first surface thereof. In this case, the character recognition unit16reads an image on the first surface of the postal matter by using the scanner, the scanned image is subjected to OCR processing, and the destination, e.g., the address and the postal code written on the postal matter is recognized. The character recognition unit16transmits a character recognition result, e.g., the address and the postal code to the control unit as destination information. The control unit determines a sorting destination of the postal matter based on the destination information received from the character recognition unit16.

The print unit17prints the sorting information representing the sorting destination on the sheet. The print unit17prints a barcode representing the sorting information on the sheet. It is satisfactory for the barcode that is printed on the sheet by the print unit17to be readable by the barcode read units15and18. For example, the print unit17prints a barcode representing the sorting information on the sheet with an ink that cannot be recognized by human eyes. It is to be noted that the print unit17may be configured to print a two-dimensional code as the barcode that is printed on the sheet. The sorting information is converted into the barcode.

The verify barcode read unit18reads an image including the barcode that is printed by the print unit17from the sheet. The verify barcode read unit18converts the image of the read barcode into information. The verify barcode read unit18transmits the information acquired from the barcode to the control unit as sorting information. The control unit decides a sorting destination (a stacker in the accumulation unit20) of the sheet based on the sorting information received from the verify barcode read unit18.

The branch unit19distributes each sheet under control of the control system. The branch unit19has gates that distribute sheets. Each gate of the branch unit19distributes sheets to any one of step paths (which will be described later) leading to the respective stackers of the later-described accumulation unit20. That is, the control system of the sheet processing apparatus1controls an operation of each gate of the branch unit19based on the sorting information of each sheet and thereby sends each sheet to any one of the step paths.

The accumulation unit20is constituted of modules M (M1, M2, M3, . . . ). Each module M has the stackers that accumulate sheets. For example, each module M has 16 stackers forming four stages and four columns. The number of the stackers in the entire accumulation unit20is the number obtained by adding the number of the stackers of all the modules. The sorting information is associated with each stacker. For example, in a mail sorting device, each destination as the sorting information is assigned to each stacker so that postal matters as sheets are aligned in the delivery order.

The accumulation unit20has step paths configured to convey each sheet distributed by the branch unit19to each module M. In the accumulation unit20, the respective modules M are coupled in accordance with each step path. The step path is a conveyance path configured to convey each sheets to the respective stackers arranged in a matrix form in each module.

Further, the accumulation unit20comprises gates. Each gage is provided in association with each stacker. Each gate is a mechanism that takes in each sheet conveyed by the step paths in the accumulation unit20into each stacker. The control system drives each gate at timing for taking each sheet into each stacker from the step path. Each gate that has been turned on guides the sheet conveyed through each step path into each corresponding stacker. Each sheet led from each step path by the gate is taken into the stacker by a taking roller or the like. Each sheet that has been taken in is accumulated in each stacker in order.

The control system performs control to accumulate each sheet having the determined sorting information into the stacker associated with the sorting information in the accumulation unit20. The control system distributes each sheet to each step path configured to convey the sheet to each stacker corresponding to the sorting information by each gate in the branch unit19. The control system operates each gate associated with the stacker corresponding to the sorting information in accordance with conveyance timing for the sheet on the step path in the accumulation unit20. As a result, the sheet sorted based on the sorting information is accumulated in each stacker in the accumulation unit20. A configuration of the control system of the sheet processing apparatus1will now be described.

FIG. 2is a block diagram showing a structural example of the control system of the sheet apparatus1.

The sheet processing apparatus1comprises a control unit101, a panel control unit111, an ejection control unit121, a conveyance control unit131, a discharge control unit141, a determination control unit151, a print control unit171, and a sorting control unit191as structures in the control system.

The control unit101integrally controls operations of the respective units in the sheet processing apparatus1. The control unit101comprises a CPU, a buffer memory, a program memory, a nonvolatile memory, and others. The CPU executes various kinds of arithmetic processing. The buffer memory temporarily stores a result of an arithmetic operation executed by the CPU. The program memory and the nonvolatile memory store various programs executed by the CPU, control data, and others. The control unit101can perform various kinds of processing when the CPU executes programs stored in the program memory.

The panel control unit111controls the operation panel10that displays a processing status of each sheet or abnormality information of the device. It is to be noted that the operation panel10is constituted of, e.g., a display device having a built-in touch panel that can display information and allow input of operations.

The ejection control unit121controls conveyance of each sheet in and around the ejection unit12. The ejection control unit121controls operations such as ejection of sheets from the supply unit11and delivery of the ejected sheets to the conveyance path. For example, the ejection control unit121comprises a CPU121a, an RAM121b, an ROM (a program memory)121c, a nonvolatile memory121d, a timer121e, a parameter table121f, and others.

The CPU121aexecutes various kinds of arithmetic processing. The RAM121btemporarily stores a result of each arithmetic operation executed by the CPU121a. For example, a detection result obtained by the sensor that detects a state of each ejected sheet is stored in the RAM121b. The ROM121cand the nonvolatile memory121dstore various programs executed by the CPU121a, control data, and others. The ROM121cis constituted of, e.g., a non-rewritable nonvolatile memory, and the nonvolatile memory121dis constituted of a writable nonvolatile memory. The ejection control unit121can realize various control functions by executing programs stored in the ROM121cor the nonvolatile memory121dby using the CPU121a. Furthermore, the timer121emeasures a time.

The parameter table121fmay be provided in, e.g., the ROM121cor the nonvolatile memory121din the ejection control unit121. The parameter table121fstores data that is used for setting timing for delivering each sheet ejected from the supply unit11to the conveyance path of the conveyance unit13. For example, in the parameter table121f, as data that should be set to control delivery of each sheet in accordance with a thickness of a preceding sheet (or a relative thickness difference from the preceding sheet), data representing, e.g., rotation timing, a rotation speed, or acceleration time of a delivery roller127.

Delivery timing of each sheet represented by the data stored in the parameter table121fis used to adjust a conveyance interval (GAP) between a sheet to be delivered and a sheet that has been delivered immediately before the former sheet (a preceding sheet). That is, the ejection control unit121controls delivery timing of each sheet ejected from the supply unit11based on the data set in the parameter table121fand thereby adjusts the conveyance interval (GAP) between two sheets conveyed in sequence on the conveyance path of the conveyance unit13.

A drive circuit122is connected to the ejection control unit121. The drive circuit122is a circuit that drives a motor123. The motor123drives an ejection roller124provided in the ejection unit12. The ejection roller124is a roller configured to eject each sheet from the supply path11. That is, the ejection control unit121controls the drive circuit122and thereby controls ejection of each sheet effected by the ejection roller124that is operated by the motor123.

Moreover, a drive circuit125is connected to the ejection control unit121. The drive circuit125is a circuit that drives a motor126. The motor126drives a delivery roller127provided in the ejection unit12. The delivery roller127is a roller configured to supply each sheet ejected by the ejection roller124to the conveyance path of the conveyance unit13in the sheet processing apparatus1. The ejection control unit121controls the drive circuit125and thereby controls delivery of each sheet effected by the delivery roller127that is operated by the motor126.

It is to be noted that the ejection roller124driven by the motor123may be configured to supply each sheet ejected from the supply unit11to the conveyance path of the conveyance unit13. In this case, in the ejection unit12, the drive circuit125and the motor126that drive the delivery roller127may be omitted, and the ejection control unit121may be configured to control timing for supplying each sheet ejected from the supply unit11to the conveyance path of the conveyance unit13by controlling driving of the ejecting roller124.

Additionally, each sensor provided in and around the ejection unit12is connected to the ejection control unit121. For example, a GAP measurement sensor (a detection sensor)128configured to detect a leading end and a trailing end of each ejected sheet is connected to the ejection control unit121. Further, a thickness measurement sensor129configured to detect a thickness of each ejected sheet is connected to the ejection control unit121. The thickness measurement sensor129measures a thickness of each sheet by using, e.g., a sensor that detects reflection of a laser beam.

The conveyance control unit131controls the conveyance unit13. The conveyance unit13conveys each sheet supplied from the ejection unit12through the conveyance path in the sheet processing apparatus. The conveyance control unit131operates a conveyance mechanism constituting the conveyance path in the sheet processing apparatus at a constant speed and thereby carries out conveyance control for conveying each sheet to each unit.

The discharge control unit141controls discharge processing of each sheet effected by the discharge unit14. The discharge control unit141checks whether each sheet should be discharged in accordance with a detection result of each sensor provided in the discharge unit14. The discharge control unit141executes control for discharging each sheet determined to be discharged.

The determination control unit151determines sorting information of each sheet (e.g., a destination such as an address and a postal code). The determination control unit151supplies the sorting information of each sheet to the control unit101. The determination control unit151acquires a barcode read result obtained by the pre-barcode read unit15, a character recognition result as the sorting information obtained by the character recognition unit16, or a barcode read result obtained by the verify barcode read unit18. The determination control unit151determines the sorting information of each sheet based on information acquired from the pre-barcode read unit15, the character recognition unit16, or the verify barcode read unit18.

The determination control unit151is connected to a barcode read unit (BCR) communication circuit152, a barcode read unit (BCR) communication circuit153, and a character recognition unit (OCR) communication circuit154.

The BCR communication circuit152is connected to the pre-barcode read unit15. The BCR communication circuit152supplies the sorting information based on a barcode read by the pre-barcode read unit15to the determination control unit151. Additionally, the BCR communication circuit153is connected to the verify barcode read unit18. The BCR communication circuit153supplies the sorting information based on a barcode read by the verify barcode read unit18to the determination control unit151. Further, the OCR communication circuit154is connected to the character recognition unit16. The OCR communication circuit154supplies to the determination control unit151a character recognition result like the sorting information obtained by OCR processing with respect to an image on the sheet read by the character recognition unit16.

The print control unit171controls printing effected by the print unit17. The print control unit171prints a barcode representing sorting information on the first surface of the sheet by using the print unit17.

The sorting control unit191executes conveyance control over each sheet in the branch unit19and the accumulation unit20. To the sorting control unit191are connected a motor drive mechanism, a gate drive mechanism, respective sensor groups, and others.

For example, the sorting control unit191controls an operation of each gate as the branch unit19. The sorting control unit191determines each stacker in which each sheet should be accumulated and operates each gate as the branch unit19so that each sheet can be distributed to each step path in the accumulation unit20configured to convey each sheet to a stacker that serves as an accumulating position.

Furthermore, the sorting control unit191controls conveyance of each sheet in the accumulation unit20and driving of each gate associated with each stacker. For example, each gate associated with each stacker is provided to each step path of the accumulation unit20. Moreover, a sensor that detects presence/absence of a sheet is provided at each position of each step path in the accumulation unit20. As a result, the sorting control unit191determines a conveyance status, e.g., a position of each sheet on each step path based on a detection signal from each sensor. The sorting control unit191controls driving of each gate associated with each stacker that should accumulate each sheet in accordance with, e.g., a conveyance status of each sheet on each step path in the accumulation unit.

A configuration of the ejection unit12will now be described.

A first structural example of the ejection unit12will be first explained.

FIG. 3is a view schematically showing an ejection unit12A as the first structural example of the ejection unit12.

The ejection unit12A shown inFIG. 3is a structural example of the ejection unit12in the sheet processing apparatus1, and the ejection unit12A and the ejection control unit121constitute the sheet ejection apparatus. Additionally, the ejection unit12A ejects sheets one by one from the supply unit11having a supply base in which the sheets as processing targets are collectively set. Further, the ejection unit12A supplies the sheets ejected from the supply unit11to the conveyance unit13.

The ejection unit12A as the first structural example of the ejection unit12depicted inFIG. 3comprises the ejection roller124, the delivery roller127, the GAP measurement sensor (a sheet detection sensor)128, a thickness measurement sensor129(129aor129b) for measuring a thickness, guide plates202,203, and204, pressure rollers205,206, and207for pressing sheets, and others.

Further, in the structural example shown inFIG. 3, the supply unit11comprises a supply base11aon which sheets are set and an ejection feed belt11bthat pushes the sheets on the supply base11atoward the ejection roller124side. In the supply unit11, sheets (sheets as processing targets) S that are to be taken into the sheet processing apparatus1are aligned and stocked on the supply base11a. The feed belt11ais provided on the supply base11a. The feed belt11bpushes the sheets S stocked on the supply base11aalong a direction of an ejection port.

In the ejection unit12A, the ejection roller124ejects the sheets set on the supply base11aof the supply unit11one by one from the ejection port side. The ejection roller124conveys each sheet ejected from the supply base11aalong the conveyance direction. Each sheet ejected by the ejection roller124is pressed by the guide plate202through the pressure roller205and conveyed toward the delivery roller127along the guide plate202in this state.

The delivery roller127operates in response to an operating instruction issued by the control system and adjusts a gap (GAP) from a preceding sheet. For example, the delivery roller127rotates by the motor126driven based on control effected by the ejection control unit121, controls delivery timing for each sheet, and thereby functions as a GAP compensation unit that adjusts the gap (GAP) from the preceding sheet. The delivery roller127is installed to face the pressure roller206for pressing each sheet. The pressure roller206is installed to be movable in accordance with a thickness of each sheet that passes between the delivery roller127and the pressure roller207. As a result, the delivery roller127and the pressure roller206sandwich each sheet therebetween with appropriate force and send the sheet by using rotation of the delivery roller127. Furthermore, the guide plate203that leads each sheet supplied from the ejection roller124side to a space between the delivery roller127and the pressure roller206is provided near the delivery roller127.

Moreover, as a sensor configured to measure the gap (GAP) from a preceding sheet, the GAP measurement sensor (the sheet detection sensor)128that determines a contact position of the delivery roller127and the pressure roller206or the vicinity of this contact position as a detecting position is provided in the ejection unit12A. The sheet detection sensor128as the GAP measurement sensor supplies a detection signal indicative of whether a sheet is present at the detecting position to the ejection control unit121. For example, the conveyance control unit121determines that a leading end of a sheet has reached the detecting position when the GAP measurement sensor128detected the sheet, and it determines that a trailing end of the sheet has passed the detecting position when the detected sheet is no longer detected.

Moreover, as to each sheet ejected by the ejection roller124, if its leading end in the conveyance direction has reached the detecting position of the GAP measurement sensor (the sheet detection sensor)128, the gap (GAP) from a preceding sheet is adjusted by the delivery roller127and the pressure roller206. For example, the ejection control unit121may temporarily stop the conveyance when the GAP measurement sensor128detected the end of the sheet ejected by the ejection roller124in the conveyance direction (when the end of the sheet reached the space between the delivery roller127and the pressure roller206), operate the delivery roller127at desired timing (delivery timing according to the set GAP), and thereby control (adjust) timing for sending the sheet to the conveyance path as the conveyance unit13in the sheet processing apparatus1.

Additionally, the ejection control unit121determines the gap (GAP) from the preceding sheet when the GAP measurement sensor128detects the end of the sheet. When the ejection control unit121has received a detection signal indicating that the end of the sheet was detected from the GAP measurement sensor128, it determines the gap based on, e.g., an elapsed time after the trailing end of the sheet sent immediately before the counterpart (the preceding sheet) passed the GAP measurement sensor128. For example, the gap from the preceding sheet is determined based on a time required until the leading end of the sheet reaches the GAP measurement sensor128after the trailing end of the preceding sheet passes the GAP measurement sensor128and a conveyance speed of the conveyance unit13. Further, a position of the preceding sheet may be identified by, e.g., a sensor provided on the conveyance path of the conveyance unit13, and then a gap between the preceding sheet and the sheet as a processing target may be determined based on the position of the preceding sheet and the detecting position of the GAP measurement sensor128.

Furthermore, in the ejection unit12A according to the first structural example is provided the thickness measurement sensor129(129aor129b) configured to detect a thickness of each sheet before the leading end of the sheet ejected by the ejection roller124reaches the contact position of the delivery roller127and the pressure roller206(the detecting position of the GAP measurement sensor128). The thickness measurement sensor (a thickness sensor)129is a sensor that measures a thickness of each sheet by using a reflective sensor or the like. In the structural example depicted inFIG. 3, as an installation example of the thickness measurement sensor (the thickness sensor)129, the thickness measurement sensors129aand129bare shown.

For example, the thickness measurement sensor129adetects a thickness of each sheet that passes above the guide plate202by using a reflective sensor provided at a position where it faces a surface of the guide plate202. Since the sheet is pressed against the guide plate202by the pressure roller205, the thickness measurement sensor129acan detect the thickness of the sheet with the surface of the guide plate202determined as a reference. Further, the thickness measurement sensor129bdetects the thickness of the sheet that passes above the guide plate203by using a reflective sensor installed at a position where it faces the surface of the guide plate203. Since the sheet is pressed against the guide plate203by the pressure roller206, the thickness measurement sensor129bcan detect the thickness of the sheet with the surface of the guide plate203determined as a reference.

The ejection control unit121stores data representing the thickness of the sheet measured by the thickness measurement sensor129(thickness information) in the RAM121b. When the GAP measurement sensor128has detected a sheet, the ejection control unit121determines a gap (GAP) between this sheet and a preceding sheet and reads the thickness information of the preceding sheet from the RAM121b. When the gap from the preceding sheet and the thickness of the preceding sheet have been identified, the ejection control unit121sets the gap (GAP) associated with the thickness of the preceding sheet by making reference to the parameter table121fand decides delivery timing for the sheet associated with the gap from the preceding sheet.

For example, if the preceding sheet has a larger thickness than the sheet to be supplied (if the preceding sheet is a sheet thicker than a predetermined thickness (which may be also referred to a thick matter hereinafter) or if the thickness of the preceding sheet is larger than the thickness of the sheet in question by a predetermined value or a higher value), the ejection control unit121sets a thick matter GAP as a gap (GAP) from the preceding sheet and supplies the sheet so that a conveyance (feed) gap from the preceding sheet can be a GAP for the thick matter.

The thick matter GAP is a GAP wider than the regular GAP, and it is a GAP that is set to prevent the sheet to be fed from catching up the preceding sheet. Setting information, e.g., the regular GAP and the thick matter GAP is stored in the parameter table121fin advance, and the ejection control unit121sets one of the regular GAP and the thick matter GAP based on the setting information stored in the parameter table121f. As a result, if delay in conveyance is expected in the sheet processing apparatus1due to the thickness of the preceding sheet, adjusting feed timing for the following sheet enables preventing the sheet to be supplied from catching up the preceding sheet.

Furthermore, if a difference between the thickness of the preceding sheet and the thickness of the sheet to be supplied is small (if the preceding sheet is not a thick matter or if a difference between the thickness of the preceding sheet and the thickness of the sheet to be supplied is less than a predetermined value), the ejection control unit121sets the regular GAP and supplies the sheet in such a manner that the gap (GAP) from the preceding sheet becomes the regular GAP.

The ejection control unit121controls delivery of the sheet using the delivery roller127as the GAP compensation unit so that the gap between the target sheet and the preceding sheet can be the set GAP (the regular GAP or the thick matter GAP). For example, the ejection control unit121drives and controls the delivery roller127that delivers the sheet based on, e.g., rotation timing, a rotation speed, or an acceleration time of the delivery roller127set by using the parameter table121fso that the GAP between the sheet and the preceding sheet can be the set GAP.

The delivery roller127delivers the sheet in the conveyance direction along the guide plate203and the pressure roller206under control of the ejection control unit121. The sheet delivered by the delivery roller127is supplied to the conveyance path in the main body of the sheet processing apparatus1as the conveyance unit13and conveyed at a constant conveyance speed. In this case, each sheet is supplied to the conveyance path in the main body of the sheet processing apparatus1so that the gap set based on the thickness of the preceding sheet and the like can be provided.

In the sheet ejection apparatus having the ejection unit12A as the first structural example, when the thickness of the preceding sheet is not smaller than the predetermined value (a thick matter) or when a difference from the thickness of the preceding sheet is not smaller than the predetermined value, the conveyance of the sheet can be delayed, and the delivery gap (GAP) between the preceding sheet and the target sheet can be expanded. As a result, in the sheet processing apparatus to which the sheets are sequentially supplied from the sheet ejection apparatus, each following sheet to be conveyed can be prevented from catching up the preceding sheet.

Control over the ejection unit12A (sheet ejection (delivery) processing) as the first structural example will now be described.

FIG. 4is a flowchart for explaining a flow of sheet ejection (delivery) processing for the ejection unit12A as the first structural example.

First, to eject out sheets as processing targets (which will be referred to as target sheets hereinafter) from the supply unit11one by one, the CPU121aof the ejection control unit121drives the ejection roller124by using the drive circuit122and the motor123(a step S11). The ejection roller124driven by the motor123ejects one sheet from the ejection port side of the supply base11ain the supply unit11and supplies the ejected sheet to the delivery roller127.

After the ejection roller124is driven, the CPU121aof the ejection control unit121judges whether the leading end of the target sheet has reached the detecting position of the GAP measurement sensor128based on a detection signal from the GAP measurement sensor128(a step S12). If it is determined that the target sheet has reached the detecting position of the GAP measurement sensor128(YES at the step S12), the CPU121aof the ejection control unit121determines a gap (GAP) to a sheet that precedes the target sheet (which will be referred to as a preceding sheet hereinafter) (a step S13). For example, in the ejection control unit121, a time at which the trailing end of the preceding sheet passed the detecting position of the GAP measurement sensor128is stored in the RAM121bin advance, and the CPU121adetermines the gap (GAP) to the preceding sheet based on a difference between a time at which the leading end of the target sheet was detected by the GAP measurement sensor128and the time at which the trailing end of the preceding sheet passed the detecting position of the GAP measurement sensor128.

Further, after the ejection roller124is driven, the CPU121aof the ejection control unit121acquires a detection signal indicative of a thickness of the target sheet from the thickness measurement sensor129(129aor129b). Upon acquiring the detection signal indicative of the thickness of the target sheet from the thickness measurement sensor129, the CPU121adetermines the thickness of the target sheet (a step S14). When the thickness of the target sheet has been determined, the CPU121astores information representing the determined thickness of the target sheet in the RAM121b(a step S15). It is to be noted that the CPU121amay acquire the detection signal indicative of the thickness from the thickness measurement sensor129as required and determine the thickness, or it may acquire the detection signal from the thickness measurement sensor129and determine the thickness when the GAP measurement sensor128has detected the leading end of the target sheet.

Upon determining the thickness of the target sheet, the CPU121areads out thickness information representing the thickness of the preceding sheet from the RAM121b(a step S16). The thickness information of the preceding sheet is obtained by measurement effected by the thickness measurement sensor129before the preceding sheet passes the detecting position of the GAP measurement sensor128, and it is stored in the RAM121b.

When the thickness information of the preceding sheet has been acquired, the CPU121ajudges whether preceding sheet is a thick matter based on the read thickness information of the preceding sheet (a step S17). For example, the CPU121ajudges whether the preceding sheet is a thick matter based on whether the thickness of the preceding sheet is higher than a predetermined reference value. If it is determined that the preceding sheet is a thick matter (YES at the step S17), the CPU121ajudges whether the target sheet is a thick matter (a step S18). For example, the CPU121ajudges whether the target sheet is a thick matter based on whether the thickness of the target sheet determined at the step S14is higher than the predetermined reference value.

If it is determined that the preceding sheet is not a thick matter (NO at the step S17) and if it is determined that the preceding sheet is a thick matter and the target sheet is also a thick matter (YES at the step S18), the CPU121asets the regular GAP as a gap (GAP) from the preceding sheet (a step S19).

If it is determined that the preceding sheet is a thick matter and the target sheet is not a thick matter (NO at the step S18), the CPU121asets the thick matter GAP, which is a wider gap than the regular GAP, as the gap (GAP) from the preceding sheet (a step S20). Setting information, e.g., the thick matter GAP and the regular GAP is stored in the parameter table121fin advance. If the preceding sheet is a thick matter and the target sheet is not a thick matter, the CPU121asets the thick matter GAP based on the setting information stored in the parameter table121f.

When the GAP (the regular GAP or the thick matter GAP) associated with the thicknesses of the preceding sheet and the target sheet has been set, the CPU121adrives the delivery roller127at timing according to the set GAP and delivers the target sheet (a step S21). In case of driving the delivery roller127and delivering the target sheet, the CPU121achecks timing which the trailing end of the target sheet passes by using a detection signal from the GAP measurement sensor128(a step S22).

When the GAP measurement sensor128has detected passage of the trailing end of the target sheet (YES at the step S22), the CPU121astores information representing a time at which the target sheet passed in the RAM121b(a step S23). For example, the CPU121amay store the time at which the target sheet passed the detecting position of the GAP measurement sensor128in the RAM121bin association with the information representing the thickness of the target sheet.

When the target sheet passes the detecting position (the delivery roller127) of the GAP measurement sensor128, the CPU121aconfirms whether a subsequent sheet as a processing target is preset in the supply unit11(a step S24). If the subsequent sheet as the processing target is present in the supply unit11(YES at the step S24), the CPU121areturns to the step S11and executes the processing of the steps S11to S24with respect to the subsequent sheet as the processing target. If the subsequent sheet as the processing target is not present in the supply unit11(NO at the step S24), the CPU121aterminates the sheet ejection processing.

According to the above-described processing, if the preceding sheet is a thick matter and the target sheet is not a thick matter, the delivery timing for the target sheet from the ejection unit12can be adjusted in such a manner that the gap between the preceding sheet and the target sheet becomes the thick matter GAP. As a result, each gap between the sheets sequentially supplied from the sheet ejection apparatus in the conveyance path in the sheet processing apparatus becomes an appropriate gap, and it is possible to avoid an inconvenience that the following sheet catches up the preceding sheet.

It is to be noted that, at the steps S17and S18, if the preceding sheet is a thick matter and the target sheet is not a thick matter (i.e., if the thickness of the preceding sheet is larger than that of the target sheet), the thick matter GAP is set, but the thick matter GAP may be set if the preceding sheet is a thick matter irrespective of the thickness of the target sheet. In this case, a judgment on whether the thick matter GAP should be set can be facilitated.

Further, in the above processing example, one of the regular GAP and the thick matter GAP is set as the gap (GAP) for the preceding sheet, GAPs in stages may be set in accordance with a difference between the thickness of the preceding sheet and the thickness of the target sheet. For example, this configuration can be realized by setting GAPs associated with differences in thickness in the parameter table121fin advance and selecting each GAP associated with each difference in thickness.

A second structural example of the ejection unit12will now be described.

FIG. 5is a view schematically showing a structural example of the ejection unit12B as the second structural example of the ejection unit12.

The ejection unit12B shown inFIG. 5is a structural example of the ejection unit12in the sheet processing apparatus1, and the ejection unit12B and an ejection control unit121constitute a sheet ejection apparatus. Further, the ejection unit12B ejects sheets one by one from a supply unit11having a supply base11aon which the sheets as processing targets are collectively set. Furthermore, the ejection unit12B supplies each sheet ejected from the supply unit11to a conveyance unit13.

As shown inFIG. 5, the ejection unit12B as the second structural example comprises an ejection roller124, a delivery roller127, a GAP measurement sensor (a sheet detection sensor)128, a thickness measurement sensor129(129aor129b), guide plates202,203, and204, pressure rollers205,206, and207for pressing sheets, and others.

As shown inFIG. 5, in the ejection unit12B as the second structural example, the respective physical structures (structures, e.g., the ejection roller124, the delivery roller127, the GAP measurement sensor (a sheet detection sensor)128, the guide plates202,203, and204, and the pressure rollers205,206, and207for pressing sheets) other than the arrangement of a thickness measurement sensor129cmay be equal to the respective structures in the ejection unit12as the first structural example shown inFIG. 3.

In the second structural example depicted inFIG. 5, the thickness measurement sensor129cis provided on the downstream side of the ejection unit12B in a conveyance direction of the delivery roller127. The thickness measurement sensor129csupplies to the CPU121aa detection signal indicative of a thickness of each sheet delivered from a contact position (a detecting position of the GAP measurement sensor128) of the delivery roller127and the pressure roller206. The thickness measurement sensor (a thickness sensor)129cmeasures a thickness of each sheet by using, e.g., a reflective sensor. In the ejection unit12B shown inFIG. 5, the thickness measurement sensor129cdetects a thickness of each sheet that passes above the guide plate204by using a reflective sensor installed at a position where it faces a surface of the guide plate204. Since each sheet is pressed by the pressure roller207and conveyed to the guide plate204in this state, the thickness measurement sensor129ccan detect a thickness of the sheet with the surface of the guide plate203determined as a reference.

Moreover, the delivery roller127functions as a GAP compensation unit that operates in response to an operating instruction issued by a control system and thereby adjusts a gap (GAP) from a preceding sheet. The ejection control unit121sets a gap (GAP) associated with a thickness of the preceding sheet based on setting information in a parameter table121fand drives the delivery roller127at delivery timing associated with the set GAP.

In the ejection unit12B as the second structural example, a detecting position of the thickness measurement sensor129is arranged on the downstream side of the delivery roller127along the conveyance direction of sheets. Therefore, in the ejection unit12B, a thickness of a target sheet cannot be determined when a leading end of the target sheet reached the delivery roller127(when the GAP measurement sensor detected the leading end of the target sheet). Therefore, as control cover the ejection unit12B, the ejection control unit121sets the GAP associated with the thickness of the preceding sheet when the GAP measurement sensor128detected the sheet.

That is, when the GAP measurement sensor128detected the sheet, the ejection control unit121reads out the thickness of the preceding sheet from an RAM121b, makes reference to the parameter table121f, and sets a gap (a regular GAP or a thick matter GAP) from the preceding sheet associated with the thickness of the preceding sheet. The ejection control unit121drives and controls the delivery roller127that supplies the sheet in accordance with rotation timing, a rotation speed, or an acceleration time of the delivery roller127set by the parameter table121fso that the GAP between the sheet and the preceding sheet can be the set GAP.

The delivery roller127delivers the sheet in the conveyance direction along the guide plate203and the pressure roller206under control of the ejection unit. The sheet delivered by the delivery roller127is supplied to the conveyance path in the main body of the sheet processing apparatus1as the conveyance unit13and conveyed at a constant conveyance speed. In this case, each sheet is supplied to the conveyance path in the main body of the sheet processing apparatus1so that the gap set based on the thickness of the preceding sheet and the like can be provided.

In the sheet ejection apparatus having the ejection unit12B as the second structural example, when the thickness of the preceding sheet is not smaller than a predetermined value (a thick matter), the conveyance of the sheet can be delayed, and the delivery gap (GAP) between the preceding sheet and the target sheet can be expanded. That is, the ejection unit12B as the second structural example can control the delivery timing of the target sheet in accordance with the thickness of the preceding sheet and, in the sheet processing apparatus1to which the sheets are sequentially supplied from the ejection unit12B, each following sheet can be prevented from catching up the preceding sheet even if a conveyance speed is lowered due to the thickness of the preceding sheet.

Control over the ejection unit12B (sheet ejection (delivery) processing) as the second structural example will now be described.

FIG. 6is a flowchart for explaining a flow of sheet ejection (delivery) processing with respect to the ejection unit12B as the second structural example.

First, the CPU121aof the ejection control unit121drives the ejection roller124(a step S31), ejects one sheet from the supply unit11, and supplies the ejected sheet to the delivery roller127. After the ejection roller124is driven, the CPU121aof the ejection control unit121judges whether a leading end of the sheet (which will be referred to as a target sheet hereinafter) ejected by the ejection roller124has reached the detecting position of the GAP measurement sensor128based on a detection signal from the GAP measurement sensor128(a step S32).

If it is determined that the target sheet has reached the detecting position of the GAP measurement sensor128(YES at the step S32), the CPU121aof the ejection control unit121determines a GAP between the target sheet and a sheet that precedes the former (which will be referred to as a preceding sheet hereinafter) (a step S33). For example, the CPU121adetermines a gap (GAP) of the preceding sheet based on an elapsed time from a time at which a trailing end of the preceding sheet passed the detecting position of the GAP measurement sensor128.

Further, after the ejection roller124is driven, the CPU121aof the ejection control unit121reads out information representing a thickness of the preceding sheet from the RAM121b(a step S34). It is assumed that the thickness information of the preceding sheet was saved in the RAM121bwhen the ejection processing for the preceding sheet was carried out. Upon acquiring the thickness information of the preceding sheet, the CPU121ajudges whether the preceding sheet is a thick matter based on the read thickness information of the preceding sheet (a step S35). For example, the CPU121ajudges whether the preceding sheet is a thick matter based on whether the thickness of the preceding sheet is larger than a predetermined reference value.

When it is determined that the preceding sheet is not a thick matter (NO at the step S35), the CPU121asets the regular GAP as the gap (GAP) from the preceding sheet (a step S36). Further, when it is determined that the preceding sheet is a thick matter (YES at the step S35), the CPU121aset the thick matter GAP, which is a wider gap than the regular GAP, as the gap (GAP) from the preceding sheet (a step S37). Data indicative of the thick matter GAP is stored in, e.g., the parameter table121f, and the CPU121amakes reference to the parameter table121fand sets the thick matter GAP.

When the GAP (the regular GAP or the thick matter GAP) associated with the thickness of the preceding sheet has been set, the CPU121adrives the delivery roller127at timing associated with the set GAP and delivers the target sheet (a step S38). After the delivery roller127was driven and the target sheet was delivered, the CPU121aof the ejection control unit121acquires a detection signal indicative of a thickness of the target sheet from the thickness measurement sensor129c.

Upon acquiring the detection signal indicative of the thickness of the target sheet from the thickness measurement sensor129c, the CPU121adetermines the thickness of the target sheet (a step S39). When the thickness of the target sheet has been determined, the CPU121astores thickness information representing the determined thickness of the target sheet in the RAM121b(a step S40). It is to be noted that the CPU121amay acquire the detection signal indicative of the thickness from the thickness measurement sensor129cas required and determine the thickness, or it may acquire the detection signal from the thickness measurement sensor129cand determine the thickness when the GAP measurement sensor128has detected a trailing end of the target sheet.

Furthermore, after the delivery roller127was driven and the target sheet was delivered, the CPU121aof the ejection control unit121checks timing at which the trailing end of the target sheet passes through the delivery roller127by using the detection signal from the GAP measurement sensor128(a step S41). When the GAP measurement sensor128has detected that the trailing end of the target sheet passed (YES at the step S41), the CPU121astores information representing a time at which the target sheet passed in the RAM121b(a step S42). For example, the CPU121amay store in the RAM121bthe time at which the sheet passed the detecting position of the GAP measurement sensor128in association with the information representing the thickness of the target sheet.

When the target sheet passed the detecting position (the delivery roller127) of the GAP measurement sensor128, the CPU121aconfirms whether a subsequent sheet as a processing target is present in the supply unit11(a step S43). If the subsequent sheet as the processing target is present in the supply unit11(YES at the step S43), the CPU121areturns to the step S31and executes the processing of the steps S31to S43with respect to the subsequent sheet as the processing target. If the subsequent sheet as the processing target is not present in the supply unit11(NO at the step S43), the CPU121aterminates the sheet ejection processing.

According to the ejection processing for the ejection unit12B as the second structural example, if the preceding sheet is a thick matter, the sheet ejection apparatus adjusts the timing for delivering the target sheet from the ejection unit12so that the gap from the preceding sheet can be the thick matter GAP. As a result, the ejection unit12B as the second example can control the timing for delivering the sheet in accordance with the thickness of the preceding sheet, a gap between the respective sheets on the conveyance path becomes an appropriate gap in the main body of the sheet processing apparatus to which the sheets are sequentially supplied from the ejection unit12B, and an inconvenience that a following sheet catches up a preceding sheet can be avoided.

It is to be noted that one of the regular GAP and the thick matter GAP is set as the gap (GAP) from the preceding sheet in the above processing example, but GAPs in stages may be set in accordance with the thickness of the preceding sheet. For example, this configuration can be realized by setting GAPs associated with thicknesses of the preceding sheets in the parameter table121fin advance, setting each GAP to be selected which is associated with each thickness of the preceding sheet, and adjusting the timing for delivering the target sheet.