JP2014210644A - Sheet feeding device, and recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeding device capable of performing stable sheet feeding without limiting a state or a type of a sheet and without increasing complication, size, and cost of the device.SOLUTION: A conveying state of a sheet is checked and a height of tray means 101 is changed on the basis of the conveying state to selectively use a state in which separation effect of the sheet is high and a state in which the separation effect is low.

Description

  The present invention relates to a sheet feeding apparatus and a recording apparatus that separate sheets one by one and feed them to adjacent processing apparatuses.

  As one of the currently known sheet feeding devices, a series of sheets are placed in a bundle on a tray, cassette, or the like (hereinafter referred to as a tray), and sequentially picked up from the top sheet by a pickup roller facing the stacking surface of the tray. Some feed to the processing position on the downstream side. In this feeding apparatus, it is necessary to separate and feed one by one from a bundle-like sheet. Examples of the sheet separation method include a method of separating the sheet bundle by abutting the leading end of the sheet bundle against an inclined portion, and a method of separating the sheet bundle by passing the sheet bundle between a feed roller and a friction member. Since these systems have a simple configuration, they may be combined to improve separation. In that case, the sheet is separated by frictional force in contact with the inclined guide member that is arranged at the front end of the tray on the downstream side of the tray and winds the sequentially fed sheets in a wedge shape, the paper feed roller that is connected to the inclined guide member, and the roller. Separating members (rollers, belts, etc.).

  In a paper feeding device, there is a case where a separation feeding mechanism is provided so as to stably feed a sheet on a tray without skewing. The separation feeding mechanism includes a reference wall that abuts the side edge of the sheet to correct the skew, and a skew feeding roller that abuts the sheet against the reference wall.

  On the other hand, depending on the type and state of the sheet to be fed, such as the material, thickness, and moisture content, problems such as jamming, double feeding, and non-feeding may easily occur during feeding. In order to cope with this problem, it is desirable to supply the relative positions of the components of the separation sheet feeding mechanism in a variable manner according to the type and state of the sheet.

  Therefore, in Patent Document 1, for example, the pickup unit and the tray unit have a configuration in which the feeding position where the uppermost sheet and the pickup unit are engaged can be set in two steps of high and low. A feeding mechanism that can be set in the vertical position is disclosed.

JP 2011-32095 A

  However, in the configuration proposed in Patent Document 1, the tray height position setting is divided into a case where a standard sheet is simply loaded and a case where sheets of different sizes are mixedly loaded. It is assumed that it does not match the state or paper type. Even if the tray height is simply set stepwise, double feeding or non-feeding may occur.

  Accordingly, an object of the present invention is to provide a sheet feeding apparatus capable of performing stable sheet feeding without being limited to the state and type of the sheet.

  Therefore, the sheet feeding apparatus according to the present invention includes a separating unit that separates the sheet from the sheet bundle by moving the inclined portion of the leading end portion of the sheet, and a placing unit that places the sheet bundle separated by the separating unit. And changing means for changing the moving distance of the leading end of the sheet in the inclined portion by changing the relative position of the separating means and the placing means based on the interval between the preceding sheet and the succeeding sheet. It is characterized by providing.

  According to the present invention, the sheet feeding device is limited to the state and type of the sheet by changing the position of the tray based on the conveyance state of the sheet, without causing the apparatus to be complicated, large, or costly. This makes it possible to carry out stable paper feeding.

It is a block diagram of the feeder which concerns on this invention. It is the figure which showed the structure of tray raising / lowering means tray movement amount detection means. 6 is a flowchart showing tray position initialization processing. It is the figure which showed typically the detection state of the sensor of a sheet | seat detection means. It is the block diagram which showed the structure of the feeding apparatus in this embodiment. 5 is a flowchart illustrating a paper feed process in the feeding device of the present embodiment. It is a figure which shows the relationship between the height of a tray, and an inclination part moving distance.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the basic configuration of the paper feed mechanism according to the present invention will be described.
FIG. 1 is a configuration diagram of a feeding device according to the present invention. The paper feed mechanism according to the present invention is a paper feed mechanism mounted in an ink jet type or electrophotographic type recording apparatus, and includes a tray unit 101 for stacking sheets and a downstream side of the tray unit 101 (feeding of the paper feed mechanism). Separating and feeding means 102 for separating and feeding the sheets one by one on the downstream side with respect to the direction. The separation feeding unit 102 includes a separation roller 102a, and a separation pad 102b that is disposed so as to be in frictional contact with the separation roller 102a and prevents double feeding of sheets. The tray means 101 can be moved up and down by a tray lifting means 209 (see FIG. 2), and can be stopped at a predetermined position. A tray movement amount detection unit 210 (see FIG. 2) is provided, and is configured to be able to detect the movement amount of the tray unit 101. Further, a paper surface detection unit 206 for detecting the initial position state of the tray movement amount detection unit 210 and detecting the uppermost sheet position is disposed above the tray unit 101. Details of the tray lifting and lowering means 209 and the tray movement amount detecting means 210 will be described later.

  A pickup roller 104 is arranged above the tray unit 101 so as to be able to contact the uppermost sheet of the sheet bundle placed on the tray unit 101 and sequentially feeds the uppermost sheet toward the separation roller 102a. When the position of the uppermost sheet is changed within a predetermined range in the vertical direction (when the uppermost sheet is moved upward relative to the initial position of sheet pickup to be described later (position H3 in FIG. 7) ), Or even when the uppermost sheet is moved downward with respect to the initial position of the sheet pickup (position H2 in FIG. 7)), the upper surface of the uppermost sheet can be contacted. Further, a separating means 105 for separating the leading edge of the sheet is disposed between the pickup roller 104 and the separating roller 102a. The separating means 105 includes an inclined portion 105a having a smooth portion that guides the leading edge of the sheet picked up by the pickup roller 104 to the separating and feeding means 102, and friction between the inclined portion 105a and the sheet in the downstream area in the conveying direction. A friction portion 105b that increases resistance is provided. The inclined portion 105a is configured as an inclined surface that raises the leading edge of the sheet conveyed by the pickup roller 104 in the sheet feeding direction.

  A sheet detection unit 106 is disposed on the downstream side of the sheet separation position by the separation feeding unit 102, and the sheet detection position by the sheet detection unit 106 is located downstream of the sheet separation position by the separation feeding unit 102. Yes. The sheet detection means 106 detects the sheet passing time, the interval between the preceding sheet and the succeeding sheet, and the like. Details of the sheet detecting means 106 will be described later. Although not shown in FIG. 1, the sheet separated by the separating and feeding unit 102 is conveyed to a recording unit or the like by a conveying unit disposed downstream of the separating and feeding unit 102.

  In such a configuration, the uppermost sheet of the sheet bundle loaded on the tray unit 101 is fed by the pickup roller 104 toward the separation roller 102a. At this time, the leading edge of the sheet is fed in the upward direction along the inclined portion 105a of the separating means 105, and the leading edge of the uppermost sheet and the lower layer sheet is wound and separated by the inclined portion 105a. The sheet fed between the separation roller 102a and the separation pad 102b by the action of the separation means 105 is reduced from being double fed.

Next, the tray lifting / lowering means 209 will be described.
FIG. 2 is a diagram showing the configuration of the tray lifting / lowering means. The tray lifting / lowering means 209 includes a tray motor 201 that is a drive source for the tray means lifting / lowering operation, a drive transmission unit 202 (here, a belt and a gear) that transmits rotational motion from the tray motor 201, a drive transmission unit 202, a tray unit 101, and the like. A rack and pinion 203 is provided. The rack portion of the rack and pinion 203 and the tray unit 101 are configured to be movable together, and the rack unit and the tray unit 101 are integrally raised and lowered according to the rotation direction of the tray motor 201. Has been. The tray means 101 is provided in the vicinity of the rack 203 in accordance with an instruction from a control device, which will be described later. The tray upper limit position detecting means 204 for detecting the upper limit position of the tray means 101, and the tray provided in the vicinity of the rack 203. The tray 101 is configured to reciprocate between the tray lower limit position detecting means 205 for detecting the lower limit position of the means 101.

    In the feeding apparatus according to the present invention, a tray loaded on the tray means 101 is used to detect the upper surface position of the sheet bundle placed on the tray means 101 and the upper face position of the tray means 101 on which no sheet is placed. A paper surface lever 103 that abuts on the uppermost sheet of the sheet moved up and down by the elevating means 209 and the upper surface of the tray means 101 and rotates up and down in accordance with the position of the tray means 101, and a paper surface lever rotated by the sheet and tray means 101 And a sheet surface detecting means 206 for detecting whether or not the 103 has been pushed up to a predetermined position. Then, based on the detection result of the paper surface detection unit 206, a control device described later detects whether the upper surface position of the sheet and the upper surface position of the tray unit 101 are located at predetermined positions. The tray movement amount detection means 210 for detecting the movement amount of the tray means 101 includes a rotary encoder 207 arranged in connection with the drive transmission unit 202, and a tray means by detecting the rotation amount of the rotary encoder 207. And encoder detection means 208 for detecting the amount of movement 101. Then, a control device described later detects the movement amount of the tray unit 101 based on the detection result of the encoder detection unit 208. Furthermore, the control device to be described later can detect the position of the tray unit 101 based on the detection result of the paper surface detection unit 206 and the detection result of the encoder detection unit 208.

  FIG. 5 is a block diagram illustrating a configuration of the feeding device according to the present embodiment. The feeding device according to the present invention includes a control device 502 that performs overall control of the feeding device. The control device 502 performs a paper feeding operation based on an instruction to the host PC 501 that is an external device. The control device 502 is connected to a tray motor 201, a sheet detection unit 106, an encoder detection unit 208, a pickup motor 503, a paper surface detection unit 206, and a clutch 504. The control device 502 includes a storage unit 510. The control device 502 is configured to control the tray motor 201, the pickup motor 503, and the clutch 504 based on the detection results of the sheet detection unit 106, the encoder detection unit 208, and the paper surface detection unit 206. The control device 502 executes the flowcharts of FIGS. 3 and 6 to be described later. In the feeding device of this embodiment, the host PC 501 is described as an external device, but the present invention is not limited to this, and the feeding device and the host PC may be provided integrally. The pickup motor 503 is configured to be able to drive a pickup roller 104 that performs a sheet pickup operation and a separation roller 102a that performs separation and feeding. A clutch 504 is provided between the pickup motor 503 and the pickup roller 104. The control device 502 can rotate the pickup roller 104 and the separation roller 102 simultaneously by turning on the clutch 504, and can rotate the separation roller 102 without rotating the pickup roller 104 by turning off the clutch 504. Further, the control device 502, the tray motor 201, the drive transmission unit 202, the rack and pinion 203, the tray unit 101, and the inclined unit 105a constitute the changing unit of the present invention.

  FIG. 3 is a flowchart showing tray position initialization processing. The tray position initialization process will be described below with reference to this flowchart. When the tray position initialization is started, the control device 502 drives the tray motor 201 to raise the tray unit 101 on which sheets are stacked in step St300. Thereafter, in step St301, in order to check whether the paper surface or tray means 101 has pushed the paper surface lever 103 to a predetermined position, the paper surface detection means 206 confirms that the paper surface lever 103 has been pushed to a predetermined position. If detected, the control device 502 determines that the paper surface or the tray means is located at a predetermined position, and stops the tray means 101 by stopping the tray motor 201 in step St302. In step St303, the control device 502 sets the upper surface position of the sheet when the tray unit 101 is stopped as the sheet pickup initial position, and ends the tray initialization. The control device 502 can change the upper surface position of the sheet by driving the tray motor 201 with the sheet pickup initial position as a reference. At the time of this change, the control device 502 can set the amount of movement of the sheet upper surface from the sheet pickup initial position based on the detection result of the encoder detection unit 208.

  Next, the sheet detection unit 106 will be described. As shown in FIG. 1, the sheet detection unit 106 is disposed on the downstream side of the sheet separation position by the separation feeding unit 102. In this embodiment, a transmission sensor (hereinafter simply referred to as a sensor) is used as the detecting means, and the sensor is configured to be shielded from light while passing through the sheet.

  FIG. 4 is a diagram schematically showing a detection result of the sensor when the sheet detection unit 106 feeds the sheet. When the sheet is fed and conveyed, the sensor is at a paper presence level 403 (hereinafter Hi), and when the sheet has been passed, the sensor indicates a paper absence level 404 (hereinafter Low). A time A401 in the figure represents the sheet passing time, and when the sheet is conveyed and the sensor detects the leading edge of the sheet, the sensor becomes Hi. When the sensor detects the trailing edge of the sheet after passing the sheet, it becomes Low. An interval B402 in the drawing represents an interval in the conveyance direction between the preceding sheet and the succeeding sheet. The control device 502 detects the sheet passing time and the sheet interval based on such a detection result of the sheet detection unit 106.

  The configuration for changing the pickup position according to the feeding state, which is a feature of the present case that can be implemented by the tray lifting / lowering unit 209, the tray movement amount detection unit 210, and the sheet detection unit 106, will be described.

  FIG. 6 is a flowchart showing a paper feed process in the feeding device of this embodiment. The characteristic sheet feeding process of the present invention will be described below with reference to this flowchart.

  First, when the control device 502 receives a paper feed execution instruction transmitted from the host PC 501, the paper feed flow starts, and the control device 502 executes tray initialization shown in FIG. The tray unit 101 is changed based on the information corresponding to the position (when the power is turned on for the first time in the feeding device, information corresponding to the position of H1 described later is stored) (St599). Thereafter, the control device 502 drives the pickup motor 503 and turns on the clutch 504 in step St600. In step St601, the sheet is fed. When feeding the second and subsequent sheets, the control device 502 causes the pickup motor to start feeding the sheet a predetermined time after the sheet detecting means 106 detects the trailing edge of the previous sheet. 503 and the clutch 504 are controlled.

  The control device 502 turns off the clutch 504 when the pickup motor 503 is rotated by a predetermined number of rotations corresponding to the distance that the leading end of the sheet passes through the separation position of the sheet by the separation and feeding unit 102. In step St <b> 603, the sheet fed by the driving of the pickup motor 503 is detected by the sheet detection unit 106, and further fed and conveyed to the conveyance unit positioned downstream of the separation feeding unit 102. In step St604, the trailing edge of the sheet is detected. Thereafter, in step St605, the control unit 502 confirms the sheet passing time. That is, the control device 502 confirms the time from when the sheet leading edge is detected by the sheet detecting means 106 until the trailing edge of the sheet is detected.

  Hereinafter, when the sheet passing time confirmed in step St605 is equal to or longer than a predetermined time (here, x) (passing time ≧ x) (Y in St606) and less than the predetermined time (passing time <x) (N in St606) Will be described. In the comparison between the sheet passing time and the predetermined time, the predetermined time is obtained by adding a value such as a conveyance error or a measurement error to a value obtained by dividing the length in the sheet feeding direction by the conveyance speed of the fed sheet. Is the time set.

  In step St606, when the passing time is equal to or longer than the predetermined time (passing time ≧ x), the trailing edge of the preceding sheet overlaps the leading edge of the succeeding sheet, and the sheet detecting unit 106 continues to indicate that paper is present. That is, the sheet separation is insufficient, and the control device 502 determines that it is in a double feed (double feed state) at this time. The control device 502 stops the pickup motor 503 in the case of Y in St606, The host PC 501 is notified that double feeding has occurred, the storage unit 510 is made to store the tray position for the next paper feeding operation (St606.5), and the paper feeding is terminated. When the tray position information is stored, information corresponding to the tray position at a position lower than the tray position when the double feed occurs is stored in the storage unit 510.

  FIG. 7 is a view showing the relationship between the height of the tray means 101 and the inclined portion moving distance. When the tray unit 101 is lowered from the tray initial position 701 (H1) (sheet pickup initial position), the height of the tray unit 101 becomes the height 702 (H2). Therefore, the moving distance of the inclined portion 105a at the leading end of the sheet is extended from the moving distance 704 (L1) to the moving distance 705 (L2). Since the sheet separation distance is extended, the separation effect is improved. Therefore, the occurrence of double feed can be suppressed. In other words, in St606.5, if the tray position at the time of occurrence of double feeding is H1, the controller 502 determines that the tray means 101 can be positioned at the H2 position during the next paper feeding operation. The information corresponding to the tray position is stored in the storage unit 510. When the tray position at the time of occurrence of double feeding is H3, the control device 502 causes the storage unit 510 to store information corresponding to the position of H1.

  Returning to the flowchart of FIG. 6, when the passing time is less than the predetermined time (passing time <x) in step St <b> 606, the control device 502 determines that there is no overlap between the preceding sheet and the succeeding sheet. The control device 502 starts feeding the succeeding sheet by turning on the clutch 504 so that the sheet detection unit 106 can start feeding the sheet after a predetermined time after detecting the trailing edge of the preceding sheet. The control device 502 turns off the clutch 504 when the pickup motor 503 is rotated by a predetermined number of rotations corresponding to the distance that the leading end of the sheet passes to the separation position of the sheet by the separation and feeding unit 102 (St608). When the leading edge of the succeeding sheet is detected in step St610, the control device 502 confirms the interval between the preceding sheet and the succeeding sheet in the control device 502 in step St611. That is, the time from when the trailing edge of the preceding sheet is detected by the sheet detecting means 106 until the leading edge of the succeeding sheet is detected is confirmed.

  A case where the confirmed sheet interval is not less than a predetermined time (here α) (sheet interval ≧ α) and a case where it is less than the predetermined time (sheet interval <α) will be described. If the sheet interval is less than the predetermined time in step St612 (sheet interval <α), the controller 502 has a narrow interval between the preceding sheet and the succeeding sheet, insufficient sheet separation, and double feed (double feed). Judge that it is easy. In step St613, the control device 502 stops the pickup motor 503. Further, in step St613, the control device 502 determines that the tray means 101 can be positioned at the H2 position during the next sheet feeding operation when the tray position when the sheet interval is confirmed is H1. Information corresponding to the tray position is stored in the storage unit 510. When the tray position when the sheet interval is confirmed is H3, the control device 502 causes the storage unit 510 to store information corresponding to the position of H1. In step St621, it is confirmed whether the sheet is the last sheet of the set number of sheets to be fed. If the sheet is the last sheet, the feeding is ended. In step St621, it is confirmed whether it is the last sheet of the set number of fed sheets. If it is not the last, the process returns to step St599, and a tray based on the correspondence to the tray position stored in the storage unit 510 after tray initialization is obtained. Change the position. That is, the control device 502 rotates the tray motor 201 in the counterclockwise direction (here, the tray lowering direction), and lowers the tray until the encoder detection unit 208 detects a predetermined rotation amount (here, Y pulse). When detecting a predetermined rotation amount, the control device 502 stops the tray motor 201.

  Therefore, as shown in FIG. 7, for example, when the tray unit 101 is lowered from the initial position 701 (H1) of the tray unit 101, the height of the tray unit 101 becomes the height 702 (H2). Therefore, the moving distance of the inclined portion 105a at the leading end of the sheet is extended from the moving distance 704 (L1) to the moving distance 705 (L2). Since the sheet separation distance is extended, the separation effect is improved. Therefore, it is possible to suppress the occurrence of double feed.

  If the sheet interval is greater than or equal to the predetermined interval in step St612 (sheet interval ≧ α), in step St616, the control device 502 further classifies the case where the sheet interval is greater than or equal to the second predetermined time (here β). When the sheet interval is equal to or longer than the second predetermined time β (sheet interval ≧ β), the control device 502 is in a state in which the load on the sheet leading edge and the inclined portion 105a is large and misfeeding is likely to occur. Judge. In step St619, the control device 502 stops the pickup motor 503. Further, in step St619, if the tray position at the time of confirming the sheet interval in step St616 is H1, the control device 502 allows the tray unit 101 to be positioned at the position H3 in the next paper feeding operation. , Information corresponding to the tray position of H3 is stored in the storage unit 510. When the tray position when the sheet interval is confirmed is H2, the control device 502 stores information corresponding to the position of H1 in the storage unit 510. In step St622, it is confirmed whether or not the set sheet is the last sheet, and if it is the last sheet, the feeding is ended. If it is not the last, the process returns to step St599, and the tray position is changed based on the correspondence to the tray position stored in the storage unit 510 after tray initialization. That is, the control device 502 rotates the tray motor 201 in the CW direction (clockwise direction) (here, the tray ascending direction), and the tray is moved until a predetermined rotation amount (here, Z pulse) is detected by the encoder detection unit 208. Raise. The control device 502 stops the tray motor 201 when detecting a predetermined rotation amount.

  Therefore, as shown in FIG. 7, for example, when the tray means 101 is raised from the initial position 701 (H1) of the tray means 101, the height of the tray means 101 becomes a height 703 (H3). Therefore, the moving distance of the inclined portion 105a at the leading end of the sheet is reduced from the moving distance 704 (L1) to the moving distance 706 (L3). That is, since the sheet separation distance is reduced, the load on the sheet is also reduced, and the occurrence of non-feed (misfeed) can be suppressed.

  The amount of rotation of the tray motor 201 in this embodiment is determined based on individual sheet information input to the sheet conveying apparatus.

  If the sheet interval is smaller than the second predetermined time β in step St616 (sheet interval <β), the controller 502 determines that the interval between the preceding sheet and the succeeding sheet is normal, and does not perform the tray operation. In step St <b> 616.5, the control device 502 stops the pickup motor 503. In step St623, it is confirmed whether or not the set sheet is the last sheet, and if it is not the end, the process returns to step St599, and if it is the last sheet, the feeding is ended.

  With the above-described configuration and control, the feeding device of the present case always performs the feeding operation in the range of sheet passing time <x, α <sheet interval <β, by constantly monitoring the sheet feeding state. Is possible. This makes it possible to suppress paper feeding troubles such as double feed (double feed) and non-feed (misfeed).

  In this embodiment, the moving distance in the inclined portion at the leading end of the sheet is changed by changing the height of the tray unit 101. However, the present invention is not limited to this, and the vertical position of the inclined portion is changed. Thus, the moving distance in the inclined portion at the front end of the sheet may be changed. In this case, the changing means of the present invention includes an inclined portion, means for moving the inclined portion, and tray means.

  In this embodiment, the movement distance in the inclined portion at the leading end of the sheet is changed by changing the height of the tray unit 101. However, the present invention is not limited to this, and a position other than the height is changed. There may be. That is, the moving distance in the inclined portion at the leading end of the sheet may be changed by changing the horizontal distance between the tray means and the inclined portion. In this case, the changing means of the present invention includes an inclined portion, a tray means, and a means for moving the inclined portion and the tray means relative to each other.

  In this way, by confirming the sheet conveyance state and changing the height of the tray means 101 based on the conveyance state, a state where the sheet separation effect is high and a state where the separation lowering is low are used properly. As a result, a sheet feeding apparatus capable of performing stable sheet feeding without being limited to the state and type of the sheet can be realized without increasing the complexity, size, and cost of the apparatus.

DESCRIPTION OF SYMBOLS 101 Tray means 103 Paper surface lever 106 Sheet detection means 201 Tray motor 208 Encoder detection means 209 Tray raising / lowering means 210 Tray movement amount detection means 503 Pickup motor

Claims (8)

Separation means for separating the sheet from the sheet bundle by moving the inclined portion of the leading end of the sheet;
Placing means for placing the sheet bundle separated by the separating means;
Changing means for changing a moving distance of the leading end of the sheet in the inclined portion by changing a relative position between the separating means and the placing means based on an interval between the preceding sheet and the succeeding sheet. A sheet feeding device characterized by the above.   2. The sheet feeding apparatus according to claim 1, wherein the changing unit increases a moving distance of the inclined portion of the leading end of the sheet as the distance between the preceding sheet and the succeeding sheet is shorter.   3. The sheet feeding apparatus according to claim 1, wherein the changing unit shortens a moving distance of the leading end of the sheet in the inclined portion as the distance between the preceding sheet and the succeeding sheet is longer.   The sheet according to any one of claims 1 to 3, wherein the changing unit changes the movement distance of the inclined portion of the leading end of the sheet by changing the position of the placing unit. Feeding device.   The sheet according to any one of claims 1 to 3, wherein the changing unit changes a moving distance of the front end of the sheet in the inclined portion by changing a height of the inclined portion. Feeding device.   The inclined portion includes a smoothing portion that reduces frictional resistance with the sheet in a region upstream of the conveyance direction, and a frictional portion that increases frictional resistance with the sheet in a region downstream of the conveyance direction. The sheet feeding apparatus according to any one of claims 1 to 5.   The sheet feeding apparatus according to any one of claims 1 to 6, wherein the changing unit sets the placing unit to a predetermined position based on individual information of the sheet. In a recording device for recording on a sheet fed from a sheet feeding device,
A recording apparatus using the sheet feeding apparatus according to claim 1 as the sheet feeding apparatus.

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