JP2022100228A - Sheet supply device - Google Patents

Abstract

To provide a sheet supply device capable of reducing sheet supply error.SOLUTION: A control part 13: controls a floating part 6 and a conveyance part 8 to convey paper P to a paper feed destination, and acquires a light receiving amount of a light receiving part 32 during floating of paper P floated by the floating part 6 for each sheet of paper conveyed by the conveyance part 8; and performs a follow-up control for raising a paper feeding table 2 when an acquired sensor value is less than a follow-up threshold value. And, the control part 13 controls the floating part 6 and the conveyance part 8 so as to retry paper feed when empty feed of paper P is performed by the conveyance part 8. Further, the control part 13 sets the follow-up threshold value so that a target position of the height position of an upper surface of a paper bundle PT in the follow-up control is a position where empty feed is more likely to occur than the double feed of paper P by the conveyance part 8.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sheet supply device that supplies sheets.

As a sheet supply device that supplies sheets, air is blown onto a bundle of paper loaded on the paper feed table to float the paper, and the top (top) paper among the floated paper is sucked and conveyed by the suction transport means. There is known a paper feeding device that feeds paper to a printing device.

In this type of paper feed device, follow-up control is performed to raise the paper feed tray as the remaining amount of paper in the paper feed tray decreases and maintain the height position of the upper surface of the paper bundle on the paper feed tray at the target position. (See Patent Document 1).

Japanese Unexamined Patent Publication No. 2019-147687

In the above-mentioned paper feed device, double feeding and blank feeding of paper may occur. Double feeding means that a plurality of sheets are overlapped and adsorbed by a suction transport means to be transported. Blank feeding means that the paper is not adsorbed by the suction transport means and the paper is not transported.

The higher the height position of the upper surface of the paper bundle on the paper feed tray, the more likely it is that double feeding will occur, and the lower the height position of the upper surface of the paper bundle, the more likely it is that blank feeding will occur. The target position on the upper surface of the paper bundle in the above-mentioned follow-up control is set to a position where double feed and blank feed are equally unlikely to occur.

By the way, when a blank feed occurs, a series of paper feed operations and a printing device at the paper feed destination can be used by consuming a small amount of time for paper feed for one sheet due to paper feed retry (refeeding). It is possible to continue the printing operation. That is, the blank feed can be relieved by the paper feed retry.

On the other hand, when double feeding occurs, in order to continue the series of feeding operations and the printing operation in the printing device at the feeding destination by the feeding retry, for example, the double-fed paper is returned to the paper feed table and fed. It needs to be redone, and this cannot be achieved without complicated mechanisms and controls. Therefore, in reality, the double feed cannot be relieved by the paper feed retry.

As described above, since the target position on the upper surface of the paper bundle in the follow-up control is set to a position where double feed and blank feed are less likely to occur, double feed occurs at the same frequency as blank feed. If double feed occurs, it cannot be relieved by a paper feed retry, so a paper feed error occurs and a series of paper feed operations stop. When a paper feed error occurs, user work is required to clear the error. Further, when a paper feed error occurs, the printing operation in the paper feed destination printing device is stopped, so that the print productivity is lowered.

The present invention has been made in view of the above, and an object of the present invention is to provide a sheet supply device capable of reducing sheet supply errors.

According to one aspect of the present invention, an elevating loading platform on which a bundle of seats is loaded, a floating upper portion that blows air onto the bundle of seats to raise the seat of the bundle of seats, and a floating upper portion that floats the bundle of seats. A transport unit that transports the highest-level sheet among the sheets to the supply destination, a detection unit that detects an output signal obtained by inputting to the side of the sheet bundle, and a floating unit that transports the sheet to the supply destination. While controlling the unit and the transport unit, the detection value of the detection unit during the floating of the sheet floated by the floating upper portion is acquired for each sheet transported by the transport unit, and the acquired detection value is obtained. The control unit is provided with a control unit that performs follow-up control for raising the loading platform when the value is less than the threshold value, and the control unit redoes the transfer of the sheet to the supply destination when the sheet is empty-fed by the transfer unit. The floating upper portion and the transport portion are controlled so as to perform the above-mentioned, and the target position of the height position of the upper surface of the sheet bundle in the follow-up control is a position where blank feed is more likely to occur than the double feed of the sheet by the transport portion. A sheet supply device is provided, which comprises setting the threshold value so as to be.

According to another aspect of the present invention, an elevating loading platform on which a bundle of seats is loaded, a floating portion that blows air onto the bundle of seats to raise the seat of the bundle of seats, and a floating portion that is floated by the floating top. A transport unit that transports the highest-level sheet among the sheets to the supply destination, a detection unit that emits light from the side of the sheet bundle to the sheet bundle side, and receives light from the sheet bundle side. The floating upper portion and the conveying portion are controlled so as to convey the sheet to the supply destination, and for each sheet conveyed by the conveying portion, the detecting portion of the detecting portion during the floating of the sheet floated by the floating upper portion. The control unit includes a control unit that acquires a light receiving amount and performs follow-up control for raising the loading platform when the acquired light receiving amount is less than the threshold value. The floating upper portion and the transport unit are controlled so as to perform a supply retry to redo the transfer of the sheet to the supply destination, and the target position of the height position of the upper surface of the sheet bundle in the follow-up control is the weight of the sheet by the transfer unit. Provided is a sheet feeding device characterized in that the threshold value is set so as to be a position where air feeding is more likely to occur than feeding.

According to another aspect of the present invention, an elevating loading platform on which a bundle of seats is loaded, a floating upper portion that blows air onto the bundle of seats to raise the seat of the bundle of seats, and a floating upper portion that floats the bundle of seats. A transport unit that adsorbs the highest-level sheet among the sheets and transports the sheet to the supply destination, and controls the floating upper portion and the transport section so as to transport the sheet to the supply destination, and also controls the sheet on the loading platform. The control unit is provided with a control unit that performs follow-up control for raising the loading platform according to the decrease, and the control unit performs a supply retry to redo the transfer of the sheet to the supply destination when the sheet is empty-fed by the transfer unit. The floating upper portion and the transport portion are controlled so as to be performed, and the suction force of the sheet by the transport portion is empty than the double feed of the sheet when the height position of the upper surface of the sheet bundle is at the target position in the follow-up control. Provided is a sheet supply device characterized by controlling the transport unit so as to have an suction force that easily causes feeding.

According to the sheet supply device of the present invention, the sheet supply error can be reduced.

It is a schematic block diagram of the paper feed device which concerns on 1st Embodiment. It is a control block diagram of the paper feed device shown in FIG. It is a figure which shows the state which a plurality of sheets have surfaced. It is a figure which shows the state that the 2nd or lessth paper from the top of the surfaced paper falls. It is a figure which shows an example of the transition of the sensor value acquired while the paper is floating for each sheet of paper to be fed. It is a flowchart for demonstrating the operation of the paper feed device when the blank feed occurs in 1st Embodiment. It is a flowchart for demonstrating the operation of the paper feed device when the blank feed occurs in 1st Embodiment. It is a flowchart for demonstrating the operation of the paper feed device when the blank feed occurs in 2nd Embodiment. It is a flowchart for demonstrating the operation of the paper feed device when the blank feed occurs in 3rd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same or equivalent parts and components are designated by the same or equivalent reference numerals throughout the drawings.

The embodiments shown below exemplify an apparatus or the like for embodying the technical idea of the present invention, and the technical idea of the present invention includes the material, shape, structure, arrangement, etc. of each component. Is not specified as the following. The technical idea of the present invention can be modified in various ways within the scope of claims.

[First Embodiment]
FIG. 1 is a schematic configuration diagram of a paper feeding device according to the first embodiment of the present invention. FIG. 2 is a control block diagram of the paper feed device shown in FIG. In the following description, the vertical and horizontal directions of the paper surface in FIG. 1 are defined as the vertical and horizontal directions.

As shown in FIGS. 1 and 2, the paper feed device (corresponding to the sheet supply device) 1 according to the first embodiment includes a paper feed table (corresponding to a loading table) 2, an end fence 3, and an elevating motor 4. , Encoder 5, floating upper part 6, separation unit 7, transport unit 8, upper limit sensor (corresponding to the detection unit) 9, a pair of paper feed rollers 10, paper feed motor 11, and paper feed inlet sensor 12. And a control unit 13.

The paper feed device 1 is a device that feeds (supplies) paper (corresponding to a sheet) P to a printing device 100 which is a paper feed destination (corresponding to a supply destination). In FIG. 1, the direction from left to right is the transport direction of the paper P by the transport unit 8 during the paper feed operation (corresponding to the sheet supply operation). In the following description, upstream and downstream mean upstream and downstream in the transport direction of the paper P by the transport unit 8.

The paper feed tray 2 is loaded with the paper P used for printing. The paper feed tray 2 is configured to be able to move up and down.

The end fence 3 is a member that regulates the position of the upstream end (left end) of the paper P on the paper feed tray 2.

The elevating motor 4 elevates and elevates the paper feed table 2.

The encoder 5 outputs a pulse signal at each predetermined rotation angle of the rotation axis of the elevating motor 4.

The floating upper portion 6 blows air from the downstream side to a paper bundle (corresponding to a sheet bundle) PT composed of a plurality of papers P stacked and loaded on the paper feed tray 2, and the upper end of the paper bundle PT. Float a plurality of sheets P of a section. The levitation portion 6 includes a levitation fan 16 and a shutter 17.

The levitation fan 16 generates a levitation airflow A1 (see FIG. 3) for levitation of the paper P of the paper bundle PT on the paper feed tray 2.

The shutter 17 switches on / off the blowing of the floating airflow A1 to the paper bundle PT.

It should be noted that two floating upper portions 6 may be further provided so as to face each other with the paper bundle PT on the paper feed table 2 interposed therebetween in the width direction orthogonal to the transport direction of the paper P.

The separation unit 7 separates the top-level paper P that is floated by the floating upper portion 6 and is adsorbed on the transport unit 8 from the second and lower sheets P from the top. The separation unit 7 includes a separation fan 18.

The separation fan 18 blows air between the top-level paper P adsorbed on the transport unit 8 and the top-top second sheet paper P to separate the top-level paper P and the top-level second or lower paper P. A separation airflow A2 (see FIG. 3) for separation is generated.

It should be noted that two separation portions 7 which face each other with the paper bundle PT on the paper feed tray 2 sandwiched in the width direction of the paper P may be further provided.

The transport unit 8 sucks and conveys the uppermost paper P among the plurality of papers P floated by the floating upper portion 6 by air suction. The transport unit 8 includes a transport belt 21, a drive roller 22, a driven roller 23, a transport motor 24, and a suction mechanism section 25.

The transport belt 21 is an annular belt that is hung between the drive roller 22 and the driven roller 23. A plurality of belt holes (not shown) are formed in the conveyor belt 21 over the entire circumference. The transport belt 21 sucks and holds the paper P by the suction force generated in the belt hole by the drive of the suction mechanism portion 25. The paper P is transported by rotating (endlessly moving) the transport belt 21 by driving the drive roller 22 while the paper P is attracted and held.

The drive roller 22 rotates (endlessly moves) the transport belt 21.

The driven roller 23 supports the transport belt 21 together with the drive roller 22. The driven roller 23 is driven and rotated by the rotating conveyor belt 21.

The transfer motor 24 rotates the drive roller 22.

The suction mechanism unit 25 sucks air through the belt hole of the conveyor belt 21 to attract the paper P to the conveyor belt 21. The suction mechanism unit 25 includes a fan (not shown) that sucks air through the belt hole.

The upper limit sensor 9 monitors the end face on the downstream side (right side) of the paper P loaded on the paper feed tray 2. The upper limit sensor 9 is arranged on the downstream side of the paper feed tray 2 at a height position where the floating paper P in the floating region F (see FIG. 3) can be detected. The levitation area F is an area in which the levitation upper portion 6 in the vertical direction floats the paper P. The upper limit sensor 9 is composed of a reflective photo sensor, and includes a light emitting unit 31 and a light receiving unit 32.

The light emitting unit 31 emits light from the right side of the paper bundle PT on the paper feed tray 2 to the left side (paper bundle PT side).

The light receiving unit 32 receives light from the left side (paper bundle PT side).

The pair of paper feed rollers 10 convey the paper P conveyed by the transfer unit 8 toward the printing device 100 arranged on the downstream side of the paper feed device 1 while niping the paper P.

The paper feed motor 11 drives the paper feed roller 10.

The paper feed inlet sensor 12 detects the paper P to be conveyed in the vicinity of the downstream side of the paper feed roller 10.

The control unit 13 controls the operation of the entire paper feeding device 1. The control unit 13 includes a CPU, RAM, ROM, a hard disk, and the like.

The control unit 13 floats the paper P at the upper end of the paper bundle PT on the paper feed tray 2, attracts the top-level paper P to the transport belt 21, and transports the top-level paper P to the printing apparatus 100. The floating upper portion 6 and the transport portion 8 are controlled.

When the paper P is blank-fed by the transport unit 8, the control unit 13 retries the paper feed (supply) until the number of consecutive blank feeds reaches a predetermined upper limit continuous number (corresponding to a predetermined number of times) R, which will be described later. The floating upper portion 6 and the transport portion 8 are controlled so as to perform (corresponding to a retry). The paper feed retry is a process of re-delivering the paper P to the printing apparatus 100.

Further, the control unit 13 receives light (sensor value) of the floating light receiving unit 32 of the paper P floated by the floating upper portion 6 for each sheet of paper conveyed by the conveying unit 8 during the paper feeding operation. Is acquired, and when the acquired sensor value is less than the tracking threshold value (corresponding to the threshold value), the tracking control for raising the paper feed tray 2 is performed. In the follow-up control, the paper feed tray 2 is raised according to the decrease in the remaining amount of the paper P on the paper feed tray 2 due to the paper feed, and the height position of the upper surface of the paper bundle PT on the paper feed tray 2 is set as the target position. It is for maintaining.

The control unit 13 tracks the target position of the height position of the upper surface of the paper bundle PT in the follow-up control during the paper feeding operation so that the blank feed is more likely to occur than the double feed of the paper P by the transport unit 8. Set the threshold.

Here, the sensor value during floating of the paper P floated by the floating upper portion 6 is the amount of received light received from the end face of the floating paper P within the detection range of the upper limit sensor 9. Therefore, the sensor value during floating of the paper P becomes larger as the number of sheets of the floating paper P within the detection range of the upper limit sensor 9 increases.

Further, the number of sheets P that can be floated by blowing air from the floating upper portion 6 is the number of sheets P in the floating area F. Therefore, the lower the height position of the uppermost paper P (upper surface of the paper bundle PT) on the paper feed tray 2 when the paper P on the paper feed tray 2 is not floating, the more air is blown by the floating upper portion 6. The number of sheets of paper P that floats is small.

From this, the height position of the upper surface of the paper bundle PT on the paper feed tray 2 when the sensor value during the floating of the paper P is assumed that the paper P on the paper feed tray 2 is not floating. Can be used as information indicating. If the height position of the paper feed tray 2 does not change, the amount of paper P that floats decreases as the paper feed progresses, and the sensor value tends to decrease.

Therefore, as described above, the paper feed device 1 performs follow-up control during the paper feed operation by using the sensor value during the floating of the paper P.

Next, the process of determining the follow-up threshold value and the follow-up control in the paper feed device 1 will be described.

The follow-up threshold is determined after the start of a series of paper feed operations. Here, it is assumed that blank feeding and double feeding of the paper P by the conveying unit 8 do not occur.

When the start of paper feeding is instructed, the control unit 13 starts raising the paper feed table 2 from a state where the upper surface of the paper bundle PT on the paper feed table 2 is below the lower limit of the detection range of the upper limit sensor 9. ..

When the upper end of the paper bundle PT on the paper feed tray 2 starts to rise within the detection range of the upper limit sensor 9, the reflected light from the right side surface of the upper end of the paper bundle PT is the upper limit sensor 9. It begins to receive light at. After that, as the paper feed tray 2 rises, the range within the detection range of the upper limit sensor 9 in the paper bundle PT on the paper feed tray 2 expands, so that the sensor value of the upper limit sensor 9 increases.

When the control unit 13 determines that the sensor value has reached a predetermined non-levitation threshold value, the control unit 13 stops the rise of the paper feed tray 2. Here, the non-levitation threshold value is set as a sensor value when the height position of the upper surface of the paper bundle PT is at a predetermined sensor position within the detection range of the upper limit sensor 9. Therefore, as described above, when the sensor value reaches the non-levitation threshold value, the paper feed tray 2 stops rising at the height position where the upper surface of the paper bundle PT is at the sensor position described above. do.

Next, the control unit 13 starts raising or lowering the paper feed tray 2, and stops the paper feed tray 2 when the upper surface of the paper bundle PT reaches a predetermined paper feed start position. As a result, the height position of the upper surface of the paper bundle PT is set to the paper feed start position. Here, the control unit 13 determines whether or not the upper surface of the paper bundle PT has reached the paper feed start position based on the number of output pulses of the encoder 5 from the time when the paper feed table 2 is started to rise or fall. do.

The paper feed start position is higher than the target position in the follow-up control. Specifically, the paper feed start position is higher than the target position by the thickness of the paper P for the total number of sheets, which is the total number of sheets excluded from sampling described later and half the number of sampling sheets described later.

Here, in the paper feeding device 1, as described above, the control unit 13 sets the target position to a position where blank feeding is more likely to occur than the double feeding of the paper P by the conveying unit 8. Specifically, the control unit 13 sets the target position to a position lower by a predetermined offset amount from an appropriate position, which is a position where both double feed and air feed are unlikely to occur. The offset amount is set so that the target position is a position where the occurrence of double feed can be suppressed while suppressing the increase in air feed, based on experiments and the like. The appropriate position and offset amount depend on the paper type (paper thickness). Therefore, the target position is set for each paper type (paper thickness).

Next, the control unit 13 starts the paper feeding operation. Specifically, the control unit 13 opens the shutter 17 and starts driving the suction mechanism unit 25, the levitation fan 16, and the separation fan 18. Further, the control unit 13 controls the paper feed motor 11 to start driving the paper feed roller 10.

After the suction mechanism portion 25, the levitation fan 16, and the separation fan 18 are started to be driven, as shown in FIG. 3, a plurality of papers P in the levitation region F are levitated by the levitation airflow A1, and the topmost paper P is a transport belt. It is adsorbed by 21.

Next, the control unit 13 closes the shutter 17. As a result, the floating airflow A1 is stopped. As a result, as shown in FIG. 4, the top-level paper P and the second and lower papers P from the top are separated by the separation airflow A2, and the second and lower papers P from the top fall.

Next, upon receiving the paper feed signal from the printing device 100, the control unit 13 starts driving the transfer motor 24, and controls the transfer unit 8 to convey the paper P. As a result, the paper P is conveyed to the printing apparatus 100 by the conveying unit 8 and the paper feed roller 10. The control unit 13 stops the transfer motor 24 after a predetermined drive time after starting the drive of the transfer motor 24.

Here, the paper feed signal is a signal that the printing device 100 instructs the paper feed device 1 to start feeding the paper P by the transport unit 8. The paper feed signal is transmitted from the printing device 100 to the paper feed device 1 for each sheet of paper fed by the paper feed device 1.

Next, the control unit 13 opens the shutter 17 to raise the paper P for the next paper feeding.

By repeating the above operation, the paper P is sequentially fed from the paper feed device 1 to the printing device 100.

When the number of sheets to be fed reaches the number of sheets excluded from sampling after the start of the paper feeding operation, the control unit 13 starts sampling the sensor value for determining the tracking threshold value.

Here, the sampling exclusion number is preset as the number of sheets to be fed without sampling the sensor value for determining the tracking threshold value immediately after the start of the feeding operation. As will be described later, immediately after the start of the paper feeding operation, the behavior of the paper P when the paper P is floated is unstable. Therefore, the sampling exclusion number is set until the number of sheets is fed. The sensor value is not sampled. Since the behavior of the paper P at the time of levitation differs depending on the paper type (paper thickness), the sampling exclusion number is set according to the paper type (paper thickness). The sampling exclusion number may be one or a plurality.

When the above-mentioned sampling is started, the control unit 13 sets the sensor value of the upper limit sensor 9 while the paper P floated for feeding the paper P next to the last paper P for the sampling exclusion number. get. After that, the control unit 13 acquires the sensor value during the floating of the floated paper P for each sheet of paper conveyed (fed) by the conveying unit 8. As the sensor value during the floating of the paper P, the control unit 13 acquires, for example, the sensor value after a predetermined time from the opening time of the shutter 17.

When the sensor values corresponding to the number of sampled sheets are acquired, the control unit 13 determines the tracking threshold value and starts the tracking control. Specifically, the control unit 13 calculates the average value of the sensor values for the acquired number of sampling sheets, and determines the calculated average value as the follow-up threshold value.

Here, the number of samples to be sampled is a number preset as the number of sheets to be fed for sampling the sensor value for determining the tracking threshold value. The number of sampling sheets can be a common value regardless of the paper type or the like, or the value can be changed according to the paper type (paper thickness).

Further, the sampling period, which is the period for acquiring the sensor values for the number of sampled sheets, is set so that the same number of sheets are fed before and after the time when the height position of the upper surface of the paper bundle PT becomes the target position. There is.

When the follow-up threshold value is determined, the control unit 13 starts the follow-up control using the determined follow-up threshold value. Until the follow-up control starts, the height position of the paper feed table 2 is fixed at the position set at the start time of the paper feed operation.

When the follow-up control is started, the control unit 13 raises the paper feed table 2 for each sheet of paper to be fed if the acquired sensor value is less than the follow-up threshold value.

Specifically, when the acquired sensor value is less than the follow-up threshold value, the control unit 13 drives the elevating motor 4 for a predetermined drive time to raise the paper feed table 2. At this time, the control unit 13 controls the drive voltage of the elevating motor 4 according to the difference between the acquired sensor value and the follow-up threshold value.

Specifically, the control unit 13 controls so that the larger the difference between the sensor value and the follow-up threshold value, the larger the drive voltage of the elevating motor 4 and the larger the amount of increase in the paper feed table 2. The larger the difference between the sensor value and the tracking threshold value, the smaller the paper P in the floating area F, and the height of the upper surface of the paper bundle PT on the paper feed tray 2 when the paper P on the paper feed table 2 is not floating. The position is low. Therefore, the control unit 13 controls so that the larger the difference between the sensor value and the tracking threshold value, the larger the amount of increase in the paper feed tray 2. The relationship between the difference between the sensor value and the follow-up threshold value and the drive voltage of the elevating motor 4 is such that the height position of the upper surface of the paper bundle PT reaches the target position by raising the paper feed tray 2. It is preset for each thickness) based on experiments and the like.

Here, FIG. 5 shows an example of the transition of the sensor value acquired while the paper P is floating for each sheet of paper fed in the paper feeding operation.

In the state where the height position of the paper feed tray 2 is fixed, the height position of the upper surface of the paper bundle PT becomes lower as the paper feeding progresses, and the paper P in the floating region F decreases. Therefore, as the number of sheets to be fed from the start of the paper feeding operation increases, the amount of paper P floated by the floating upper portion 6 decreases. Therefore, as the number of sheets to be fed from the start of the paper feeding operation increases, the sensor value acquired during the floating of the paper P for each paper to be fed becomes smaller.

However, immediately after the start of the paper feeding operation, the behavior of the paper P when the paper P is floated tends to be unstable. For example, air may not enter well between the sheets, and a plurality of sheets of sheets P may float while being in close contact with each other. In such a case, the sensor value becomes smaller than when the floating papers P are separated from each other. For this reason, as shown in FIG. 5, immediately after the start of the paper feeding operation, the sensor value tends to be smaller than the expected value and becomes unstable. In particular, the sensor value tends to be unstable when the first sheet is fed.

Therefore, as described above, in the paper feed device 1, the sampling exclusion number is set so that the sensor value is not sampled immediately after the start of the paper feed operation.

Then, in the paper feeding device 1, as shown in FIG. 5, a sampling period including a time point at which the height position of the upper surface of the paper bundle PT becomes the target position is set. Further, as described above, the sampling period is set so that the same number of sheets are fed before and after the time when the height position of the upper surface of the paper bundle PT becomes the target position.

The appropriate threshold value shown in FIG. 5 is different from the present embodiment and is a follow-up threshold value in the case of performing follow-up control for maintaining the height position of the upper surface of the paper bundle PT at the above-mentioned appropriate position. That is, the appropriate threshold value is a value at which double feeding and blank feeding of the paper P by the conveying unit 8 are equally unlikely to occur. When the follow-up threshold value is larger than the appropriate threshold value, double feed is more likely to occur than blank feed, and when the follow-up threshold value is smaller than the appropriate threshold value, blank feed is more likely to occur than double feed. As described above, in the present embodiment, the target position is set to a position lower than the appropriate position, the follow-up threshold value is smaller than the appropriate threshold value, and the value is such that blank feed is more likely to occur than double feed.

Next, the operation of the paper feed device 1 when blank feeding occurs will be described with reference to the flowcharts of FIGS. 6 and 7.

The processing of the flowcharts of FIGS. 6 and 7 starts when the paper feeding operation is started.

In step S1 of FIG. 6, the control unit 13 determines whether or not the paper feed end instruction from the printing device 100 has been received. The paper feed end instruction is transmitted by the printing device 100 to instruct the paper feed device 1 to end the paper feed. The paper feed end instruction is transmitted by the printing device 100 to the paper feed device 1 when the paper feed for the number of paper sheets in the series of paper feed operations is completed and when the error notification from the paper feed device 1 is received. It is a thing.

When it is determined that the paper feed end instruction has been received (step S1: YES), the control unit 13 ends a series of paper feed operations.

When it is determined that the paper feed end instruction has not been received (step S1: NO), in step S2, the control unit 13 determines whether or not the sensor values corresponding to the number of sampling sheets described above have been acquired.

When it is determined that the sensor values corresponding to the number of sampled sheets have not been acquired (step S2: NO), in step S3, the control unit 13 determines whether or not the paper feed signal from the printing device 100 has been received. If it is determined that the paper feed signal has not been received (step S3: NO), the control unit 13 repeats step S3.

When it is determined that the paper feed signal has been received (step S3: YES), in step S4, the control unit 13 controls the transport unit 8 to transport the paper P. Here, at the time when the paper feed device 1 receives the paper feed signal, as described above, the uppermost paper P among the plurality of paper P floated by the floating upper portion 6 is attracted to the transport belt 21. It is in a state.

Next, in step S5, the control unit 13 determines whether or not the blank feeding of the paper P by the transport unit 8 has occurred. Here, if the control unit 13 does not detect the paper P transported from the transport unit 8 within a predetermined time after the paper P is transported by the transport unit 8 in step S4, the control unit 13 does not detect the paper P transported from the transport unit 8. Judge that air transportation has occurred.

When it is determined that a blank feed has occurred (step S5: YES), in step S6, the control unit 13 adds "1" to the continuous blank feed count value Ca. The continuous blank feed count value Ca indicates the number of times of continuous blank feed of the paper P by the transport unit 8. Here, at the start of a series of paper feeding operations, the continuous blank feed count value Ca = 0 is set.

Next, in step S7, the control unit 13 determines whether or not the continuous blank feed count value Ca has reached the upper limit continuous number of times R (Ca = R). The upper limit number of consecutive blank feeds R is set as a reference for the number of consecutive blank feed occurrences for determining whether or not to complete the repetition of paper feed retry and perform an error notification by blank feed. The upper limit continuous number R may be once or a plurality of times. The upper limit continuous number R is set in advance based on an experiment or the like.

When it is determined that the continuous blank feed count value Ca has not reached the upper limit continuous number R (step S7: NO), the control unit 13 returns to step S1.

Here, in the paper feed device 1, if the paper P is blankly fed by the transport unit 8 after the start of a series of paper feeding operations until the tracking threshold value is determined, the blank feed occurs. The sensor value sampled at times is not adopted as the sensor value for determining the tracking threshold value. That is, the control unit 13 does not include the sensor value sampled when the blank feed occurs in the sensor value corresponding to the number of sampled sheets.

Therefore, when the determination is "NO" in step S7 and the process returns to step S1 and the paper feed end instruction is not received (step S1: NO), in step S2, the control unit 13 is a sensor for the number of sampling sheets. It is determined that the value has not been acquired (step S2: NO). Then, when the paper feed signal is received (step S3: YES), the control unit 13 conveys the paper P by the conveying unit 8 (step S4). At this time, the control unit 13 raises a plurality of papers P of the paper bundle PT by the floating upper portion 6 by opening the shutter 17, adsorbs the uppermost paper P to the transport belt 21, and attracts the paper P to the transport unit. It is conveyed by 8. In this way, paper feed retry is performed.

When it is determined in step S7 that the continuous blank feed count value Ca has reached the upper limit continuous number of times R (step S7: YES), in step S8, the control unit 13 transmits an error notification by blank feed to the printing device 100. .. After this, the control unit 13 returns to step S1.

Here, the printing device 100 that has received the error notification sends a paper feeding end instruction to the paper feeding device 1. Therefore, when returning from step S8 to step S1, the control unit 13 determines that the paper feed end instruction has been received (step S1: YES), and ends a series of paper feed operations as a paper feed error.

When it is determined in step S5 that no blank feed has occurred (step S5: NO), in step S9, the control unit 13 clears the continuous blank feed count value Ca (Ca = 0). After this, the control unit 13 returns to step S1.

When it is determined in step S2 that the sensor values corresponding to the number of sampled sheets have been acquired (step S2: YES), in step S10, the control unit 13 determines the follow-up threshold value and starts the follow-up control as described above. After that, the control unit 13 proceeds to step S11 in FIG.

Here, as described above, in the paper feed device 1, the sensor value sampled when the blank feed occurs is not included in the sensor value for the number of sampled sheets. Therefore, when the acquisition of the sensor value for the number of sampled sheets is completed, the last sheet P for the number of sampled sheets is conveyed without being empty-fed. Therefore, when the follow-up threshold value is determined and the follow-up control is started in step S10, the continuous blank feed count value Ca = 0.

The processing of steps S11 to S17 of FIG. 7 is the same as the processing of steps S1 and S3 to S8 of FIG. 6 described above.

If it is determined in step S16 that the continuous blank feed count value Ca has not reached the upper limit continuous number of times R (step S16: NO), in step S18, is the control unit 13 the continuous blank feed count value Ca = 1? Judge whether or not.

When it is determined that the continuous blank feed count value Ca = 1 (step S18: YES), in step S19, the control unit 13 adds "1" to the intermittent blank feed count value Cb. After this, the control unit 13 proceeds to step S20.

The intermittent blank feed count value Cb indicates the number of times of intermittent blank feed of the paper P by the transport unit 8. At the start of a series of paper feed operations, the intermittent blank feed count value Cb = 0 is set.

If it is determined in step S18 that the continuous blank feed count value Ca = 1 (step S18: NO), the control unit 13 skips step S19 and proceeds to step S20.

In step S20, the control unit 13 forcibly raises the paper feed tray 2 by a predetermined amount of increase. Here, the control unit 13 can determine the amount of increase in the paper feed table 2 based on the number of output pulses of the encoder 5.

The forced ascent of the paper feed tray 2 in step S20 is performed separately from the ascent of the paper feed tray 2 by the follow-up control. The forced ascent of the paper feed tray 2 is performed in order to suppress the continuous occurrence of blank feed. The above-mentioned predetermined amount of increase in the forced increase of the paper feed table 2 is set in advance based on an experiment or the like as a value capable of suppressing continuous occurrence of blank feeding.

Forcibly raising the paper feed table 2 in step S20 means that the paper feed table 2 is forcibly raised by a predetermined amount of increase when the paper P is idlely fed by the transport unit 8 during the follow-up control. Means to let you.

Next, in step S21, the control unit 13 determines whether or not the intermittent air feed count value Cb has reached the predetermined upper limit number of intermittent times (corresponding to the number of intermittent times) D (Cb = D). The upper limit number of intermittent feeds D is set as a reference for the number of intermittent blank feeds to be used for determining whether or not to increase the follow-up threshold value in order to suppress the occurrence of blank feeds. The upper limit number of intermittent times D is set to a plurality of times. The upper limit number of intermittent times D is set in advance based on an experiment or the like.

When it is determined that the intermittent air feed count value Cb has not reached the upper limit number of intermittent feeds D (step S21: NO), the control unit 13 returns to step S11.

When the paper feed end instruction is not received (step S11: NO) and the paper feed signal is received (step S12: YES) when the determination is "NO" in step S21 and the process returns to step S11, the control unit 13 , The paper P is conveyed by the conveying unit 8 (step S13). At this time, the control unit 13 raises a plurality of papers P of the paper bundle PT by the floating upper portion 6 by opening the shutter 17, adsorbs the uppermost paper P to the transport belt 21, and attracts the paper P to the transport unit. It is conveyed by 8. In this way, paper feed retry is performed.

When it is determined in step S21 that the intermittent blank feed count value Cb has reached the upper limit number of intermittent feeds D (step S21: YES), in step S22, the control unit 13 increases the follow-up threshold value by a predetermined amount. As a result, it is possible to reduce the subsequent air transportation. How large the follow-up threshold value (the above-mentioned predetermined amount) is set in advance based on an experiment or the like as a value capable of reducing air feeding.

Next, in step S23, the control unit 13 clears the intermittent air feed count value Cb (Cb = 0). After this, the control unit 13 returns to step S11.

When it is determined in step S14 that no blank feed has occurred (step S14: NO), in step S24, the control unit 13 clears the continuous blank feed count value Ca (Ca = 0). After this, the control unit 13 returns to step S11.

If the paper P is double-fed by the transport unit 8 during the paper feeding operation, the control unit 13 transmits an error notification due to the double-feeding to the printing apparatus 100. After that, the control unit 13 receives the paper feed end instruction from the printing device 100, and ends a series of paper feed operations as a paper feed error.

Here, the double feed of the paper P by the transport unit 8 is detected by, for example, a double feed sensor (not shown) provided in the vicinity of the paper feed roller 10. The paper feed inlet sensor 12 may be configured to function as a double feed sensor.

As described above, in the paper feed device 1, in the control unit 13, the target position of the height position of the upper surface of the paper bundle PT in the follow-up control is more blank than the double feed of the paper P by the transport unit 8. Set the tracking threshold so that the position is easy. As a result, it is possible to reduce double feed, which cannot be relieved by the paper feed retry and causes a paper feed error. On the other hand, although blank feeding is likely to occur, when blank feeding occurs, the control unit 13 performs paper feed retry until the number of continuous blank feedings reaches the upper limit continuous number R. As a result, by relieving the blank feed by the paper feed retry, it is possible to suppress a paper feed error even if the blank feed occurs. As a result, according to the paper feed device 1, the paper feed error can be reduced.

Further, in the paper feeding device 1, when the number of times of continuous blank feeding of paper P by the conveying unit 8 (continuous blank feeding count value Ca) reaches the upper limit continuous number R, the control unit 13 feeds the paper after that. Ends a series of paper feed operations without retrying. As a result, it is possible to prevent the blank feed and the paper feed retry from being unnecessarily repeated because the follow-up threshold value is set so that the target position is a position where the blank feed is more likely to occur than the double feed. Further, it is possible to prevent the blank feed and the paper feed retry from being unnecessarily repeated due to some other cause (such as the paper P being caught on a member or the like in the apparatus). It is possible to prevent unnecessary repetition of blank feed and paper feed retry from the start of a series of paper feed operations to the time when the follow-up threshold value is determined and the follow-up control is started.

Further, in the paper feed device 1, if the paper P is blankly fed by the transport unit 8 between the start of a series of paper feed operations and the determination of the follow-up threshold value, the control unit 13 samples when the blank feed occurs. The sensor value is not adopted as the sensor value for determining the tracking threshold value. As a result, even if a blank feed occurs before the follow-up threshold value is determined, it is possible to suppress a decrease in the accuracy of the follow-up threshold value.

Further, in the paper feed device 1, the control unit 13 forcibly raises the paper feed table 2 by a predetermined amount of increase when the paper P is blankly fed by the transport unit 8 during the execution of the follow-up control. As a result, it is possible to suppress the continuous occurrence of air transportation.

Further, in the paper feed device 1, the control unit 13 reaches the upper limit number of intermittent feeds D in the number of intermittent blank feed occurrences (intermittent blank feed count value Cb) of the intermittent paper P by the transport unit 8 while the follow-up control is being executed. If so, the tracking threshold is increased by a predetermined amount. As a result, when the tracking threshold value is set to a value that is too small and the situation is such that blank feeding is likely to occur, the situation can be improved.

When it is determined that the intermittent air feed count value Cb has reached the upper limit number of intermittent feeds D, the suction force of the paper P by the transport unit 8 is increased by a predetermined amount as in the fourth embodiment described later. May be good. Further, when it is determined that the intermittent air feed count value Cb has reached the upper limit number of intermittent feeds D, a process of increasing the follow-up threshold value by a predetermined amount and a process of increasing the suction force of the paper P by the transport unit 8 by a predetermined amount. May be combined. When combining the process of increasing the tracking threshold value and the process of increasing the suction force of the paper P by the transport unit 8, how much the tracking threshold value and the suction force of the paper P by the transport unit 8 should be increased is determined by blank feeding. For example, it may be determined based on an experiment or the like so that

[Second Embodiment]
Next, a second embodiment in which a part of the operation of the paper feed device 1 when blank feeding occurs in the above-mentioned first embodiment will be described.

FIG. 8 is a flowchart for explaining the operation of the paper feed device 1 when blank feeding occurs in the second embodiment.

The processing of steps S31 to S35 of FIG. 8 is the same as the processing of steps S1 to S5 of FIG. 6 described above.

If it is determined in step S35 that no blank feed has occurred (step S35: NO), the control unit 13 returns to step S31.

Here, when it is determined as "NO" in step S35 and the process returns to step S31, the paper feed end instruction is not received (step S31: NO), and the sensor values for the number of sampled sheets have not been acquired yet (step S31: NO). In step S32: NO), when the paper feed signal is received (step S33: YES), the control unit 13 conveys the paper P by the conveying unit 8 (step S34). At this time, the control unit 13 raises a plurality of papers P of the paper bundle PT by the floating upper portion 6 by opening the shutter 17, adsorbs the uppermost paper P to the transport belt 21, and attracts the paper P to the transport unit. It is conveyed by 8. In this way, paper feed retry is performed.

When it is determined that the blank feed has occurred (step S35: YES), in step S36, the control unit 13 transmits an error notification by the blank feed to the printing apparatus 100. After this, the control unit 13 returns to step S31.

Here, the printing device 100 that has received the error notification sends a paper feeding end instruction to the paper feeding device 1. Therefore, when returning from step S36 to step S31, the control unit 13 determines that the paper feed end instruction has been received (step S31: YES), and ends a series of paper feed operations as a paper feed error. As a result, if a blank feed of the paper P by the transport unit 8 occurs between the start of a series of paper feed operations and the determination of the follow-up threshold value, the control unit 13 does not perform a supply retry and causes a paper feed error. End a series of sheet supply operations.

When it is determined in step S32 that the sensor values corresponding to the number of sampled sheets have been acquired (step S32: YES), in step S37, the control unit 13 determines the follow-up threshold value in the same manner as in step S10 of FIG. Start tracking control. After that, the control unit 13 proceeds to step S11 in FIG. 7 described above, and executes the subsequent processing.

As described above, in the second embodiment, the control unit 13 supplies a series of sheets without performing a supply retry when the paper P is blankly fed by the transport unit 8 until the follow-up threshold value is determined. End the operation. As a result, it is possible to avoid determining the follow-up threshold value in a state in which some cause that tends to cause empty feeding is inherent. Therefore, it is possible to avoid repeating blank feeding and feeding retry after the paper feeding operation has progressed, or the continuous blank feeding count value Ca reaching the upper limit continuous number R and causing a paper feeding error. That is, the user can take corrective action at an early stage by setting a paper feed error at an early stage after the start of the paper feed operation.

[Third Embodiment]
Next, a third embodiment in which a part of the operation of the paper feed device 1 when blank feeding occurs in the above-mentioned first embodiment will be described.

FIG. 9 is a flowchart for explaining the operation of the paper feed device 1 when blank feeding occurs in the third embodiment.

In the third embodiment, when the paper feeding operation is started, the processes of steps S1 to S10 in FIG. 6 described above are performed in the same manner as in the first embodiment. In the third embodiment, after step S10 in FIG. 6, the process proceeds to step S41 in FIG. The processes of steps S31 to S37 of FIG. 8 described in the second embodiment may be performed, and the process may proceed to step S41 of FIG. 9 after step S37 of FIG.

The process of steps S41 to S49 of FIG. 9 is the same as the process of steps S11 to S19 of FIG. 7 described above.

In step S50 of FIG. 9, the control unit 13 determines whether or not the continuous blank feed count value Ca has reached a predetermined continuous number of consecutive times K (Ca = K). The specified number of consecutive blank feeds K is set as a reference for the number of consecutive blank feeds to be generated in order to determine whether or not to forcibly raise the paper feed tray 2 in order to suppress the occurrence of blank feeds. .. The specified number of consecutive times K is set to a plurality of times. The specified number of consecutive times K is set in advance based on an experiment or the like as a value capable of suppressing the occurrence of blank feeding while avoiding excessively raising the paper feed tray 2. In the third embodiment, the upper limit continuous number R is set to be larger than the specified continuous number K.

When it is determined that the continuous blank feed count value Ca has reached the specified number of consecutive times K (step S50: YES), in step S51, the control unit 13 sets the paper feed tray 2 in the same manner as in step S20 of FIG. Forcibly raise by a predetermined amount. After this, the control unit 13 proceeds to step S52.

When it is determined that the continuous blank feed count value Ca has not reached the specified number of consecutive times K (step S50: NO), the control unit 13 skips step S51 and proceeds to step S52. As a result, the control unit 13 does not forcibly raise the paper feed table 2 until the blank feeding of the paper P by the transport unit 8 is repeated up to the specified continuous number of times K during the execution of the follow-up control.

The processing of steps S52 to S55 is the same as the processing of steps S21 to S24 of FIG. 7 described above.

As described above, in the third embodiment, the control unit 13 forcibly feeds the paper feed table 2 until the blank feed of the paper P by the transport unit 8 is repeated up to the specified continuous number of times K during the execution of the follow-up control. Do not make a sharp rise. As a result, it is possible to suppress the occurrence of blank feed while suppressing an increase in the risk of double feed due to the excessively raised paper feed tray 2.

[Fourth Embodiment]
Next, a fourth embodiment in which a part of the first embodiment described above is modified will be described.

In the fourth embodiment, the control unit 13 feeds the paper P by the transport unit 8 in a blank manner rather than the double feed of the paper P when the height position of the upper surface of the paper bundle PT is at the target position in the follow-up control. The transport unit 8 is controlled so that the suction force is likely to be generated. Specifically, the control unit 13 sets the suction air volume of the suction mechanism unit 25 of the transport unit 8 during the paper feeding operation to an air volume smaller than the appropriate air volume. The appropriate air volume is a suction air volume in which double feeding and air feeding are equally unlikely to occur when the height position of the upper surface of the paper bundle PT is at the target position in the follow-up control.

Here, in the transport unit 8, if the height position of the upper surface of the paper bundle PT is the same, the smaller the suction air volume of the suction mechanism portion 25, the smaller the suction force of the paper P to the transport belt 21, and the transport belt 21. Since the frictional force between the paper P and the paper P becomes small, blank feeding of the paper P is likely to occur.

Also in the fourth embodiment, the process of determining the follow-up threshold value and the follow-up control are performed in the same manner as in the first embodiment described above.

That is, when the start of paper feeding is instructed, the control unit 13 adjusts the height position of the paper feed table 2 so that the upper surface of the paper bundle PT is the total number of sheets excluded from sampling and half the number of sampling sheets. Set the paper feed start position at a position higher than the target position by the thickness of the paper P for the minute.

Next, the control unit 13 starts the paper feeding operation. At this time, the control unit 13 sets the suction air volume of the suction mechanism unit 25 to an air volume smaller than the above-mentioned appropriate air volume, and starts driving the suction mechanism unit 25. The suction air volume of the suction mechanism unit 25 is set to a suction air volume that can suppress the occurrence of double feed while suppressing the increase in blank feed during the execution of the follow-up control, according to the paper type and the paper size. The suction air volume of the suction mechanism unit 25 according to the paper type and the paper size is, for example, experimentally determined in advance.

When the number of sheets to be fed reaches the number of sheets excluded from sampling after the start of the paper feeding operation, the control unit 13 starts sampling the sensor value for determining the tracking threshold value. When the sensor values corresponding to the number of sampled sheets are acquired, the control unit 13 determines the tracking threshold value and starts the tracking control.

When the follow-up threshold value is determined, the control unit 13 starts the follow-up control using the determined follow-up threshold value. When the follow-up control is started, the control unit 13 raises the paper feed table 2 for each sheet of paper to be fed if the acquired sensor value is less than the follow-up threshold value.

As described above, since the suction air volume of the suction mechanism unit 25 is set to an air volume smaller than the appropriate air volume, the paper feeding operation is performed in a situation where blank feeding is more likely to occur than double feeding.

Next, the operation of the paper feed device 1 when blank feeding occurs in the fourth embodiment will be described.

The operation of the paper feed device 1 when blank feeding occurs in the fourth embodiment is the operation described with reference to the flowcharts of FIGS. 6 and 7 in the first embodiment described above, except for the process of step S22 of FIG. Is similar to.

In the fourth embodiment, the process of increasing the follow-up threshold value in step S22 of FIG. 7 by a predetermined amount is replaced with the process of increasing the suction force of the paper P by the transport unit 8 by a predetermined amount. That is, when it is determined that the intermittent air feed count value Cb has reached the upper limit number of intermittent feeds D (step S21: YES), the control unit 13 increases the suction force of the paper P by the transport unit 8 by a predetermined amount.

Specifically, the control unit 13 increases the suction air volume of the suction mechanism unit 25 by a predetermined air volume. As a result, it is possible to reduce the subsequent air transportation. How much the suction force of the paper P by the transport unit 8 should be increased, that is, how much the suction air volume of the suction mechanism unit 25 should be increased (predetermined air volume described above) is based on experiments and the like as a value that can reduce air feeding. It is preset.

As described above, in the fourth embodiment, in the control unit 13, the suction force of the paper P by the transport unit 8 is such that the suction force of the paper P is more likely to occur than the double feed of the paper P during the follow-up control. The transport unit 8 is controlled so as to be. As a result, as in the first embodiment, it is possible to reduce the double feed that cannot be relieved by the paper feed retry and causes a paper feed error. On the other hand, although blank feeding is likely to occur, when blank feeding occurs, the control unit 13 performs paper feed retry until the number of continuous blank feedings reaches the upper limit continuous number R. As a result, by relieving the blank feed by the paper feed retry, it is possible to suppress a paper feed error even if the blank feed occurs. As a result, paper feed errors can be reduced.

Further, also in the fourth embodiment, as in the first embodiment, in the control unit 13, the number of times of continuous blank feeding of the paper P by the transporting unit 8 (continuous blank feeding count value Ca) has reached the upper limit continuous number R. In that case, after that, a series of paper feed operations are terminated without performing paper feed retry. As a result, it is possible to prevent the blank feed and the paper feed retry from being unnecessarily repeated.

Further, also in the fourth embodiment, as in the first embodiment, when the control unit 13 causes blank feeding of the paper P by the transport unit 8 between the start of a series of paper feeding operations and the determination of the follow-up threshold value. , The sensor value sampled when the blank feed occurs is not adopted as the sensor value for determining the tracking threshold value. As a result, even if a blank feed occurs before the follow-up threshold value is determined, it is possible to suppress a decrease in the accuracy of the follow-up threshold value.

Further, also in the fourth embodiment, as in the first embodiment, the control unit 13 forces the paper feed tray 2 by a predetermined amount of increase when the paper P is blankly fed by the transport unit 8 during the execution of the follow-up control. Raise the target. As a result, it is possible to suppress the continuous occurrence of air transportation.

Further, in the fourth embodiment, the control unit 13 reaches the upper limit number of intermittent feeds D in the number of intermittent blank feed occurrences (intermittent blank feed count value Cb) of the intermittent paper P by the transport unit 8 during the execution of the follow-up control. If this is the case, the suction force of the paper P by the transport unit 8 is increased by a predetermined amount. As a result, when the suction force of the paper P by the transport unit 8 is too small and the situation is such that blank feeding is likely to occur, the situation can be improved.

Also in the fourth embodiment, as in the second embodiment, the control unit 13 does not perform a supply retry when the paper P is idlely fed by the transport unit 8 until the follow-up threshold value is determined. A series of sheet supply operations may be terminated. As a result, the user can take corrective action at an early stage by causing a paper feed error at an early stage after the start of the paper feed operation.

Further, also in the fourth embodiment, as in the third embodiment, the control unit 13 feeds paper until the blank feed of the paper P by the transport unit 8 during the execution of the follow-up control is repeated up to a specified continuous number of times K. It may be possible not to forcibly raise the table 2. As a result, it is possible to suppress the occurrence of blank feed while suppressing an increase in the risk of double feed due to the excessively raised paper feed tray 2.

Further, when it is determined that the intermittent air feed count value Cb has reached the upper limit number of intermittent feeds D, the follow-up threshold value may be increased by a predetermined amount as in the first embodiment. Further, when it is determined that the intermittent air feed count value Cb has reached the upper limit number of intermittent feeds D, a process of increasing the follow-up threshold value by a predetermined amount and a process of increasing the suction force of the paper P by the transport unit 8 by a predetermined amount. May be combined. When combining the process of increasing the tracking threshold value and the process of increasing the suction force of the paper P by the transport unit 8, how much the tracking threshold value and the suction force of the paper P by the transport unit 8 should be increased is determined by blank feeding. For example, it may be determined based on an experiment or the like so that

[Other embodiments]
As mentioned above, the invention has been described by the first to fourth embodiments, but the discourses and drawings that form part of this disclosure should not be understood to limit the invention. This disclosure will reveal to those skilled in the art various alternative embodiments, examples and operational techniques.

In the first to fourth embodiments described above, the same number of sheets are fed before and after the sampling period in the process of determining the follow-up threshold value when the height position of the upper surface of the paper bundle PT becomes the target position. Was set to, and the average value of the sampled sensor values was determined as the follow-up threshold value. However, the number of sheets to be fed before and after the time when the height position of the upper surface of the paper bundle PT becomes the target position in the sampling period may be different from each other. In this case, for example, the average value of the sensor values for the sampled sheets is adjusted and followed according to the number of sheets to be fed before and after the time when the height position of the upper surface of the paper bundle PT becomes the target position in the sampling period. The threshold can be determined.

If the behavior of the floated paper P is stable even immediately after the start of the paper feed operation, it is omitted to set the sampling exclusion number immediately after the start of the paper feed operation, and the paper feed operation is started. It is possible to start the sampling period with. For example, by sending air between the papers P of the paper bundle PT before the start of the paper feeding operation, it is possible to prevent the plurality of sheets of paper P from floating while being in close contact with each other and to stabilize the behavior of the paper P. In the configuration, the sampling period may be started at the same time as the paper feed operation is started.

Further, as described above, if the behavior of the floated paper P is stable even immediately after the start of the paper feeding operation, the sensor value sampled at the time of conveying the first sheet of paper P in the paper feeding operation is used. The follow-up threshold may be determined. In this case, the height position of the paper feed tray 2 at the start of the paper feed operation is set so that the height position of the upper surface of the paper bundle PT is the target position during the paper feed operation. Then, the floating sensor value of the floated paper P for conveying the first sheet P in the paper feeding operation is sampled, the sensor value is determined as the follow-up threshold value, and the follow-up control is started. In the process of determining the follow-up threshold value, when at least one sheet of paper P is conveyed after the start of the paper feeding operation, the sensor value during the floating of the paper P floated by the floating top 6 is sampled, and the sampled sensor value is used. It may be used as long as it is used to determine the tracking threshold value.

In the first to fourth embodiments described above, the sensor value during the floating of the paper P is sampled to determine the follow-up threshold value after the start of the paper feed operation, but the follow-up control is performed using the preset follow-up threshold value. There may be.

In the first to fourth embodiments described above, the upper limit sensor 9 is composed of an optical sensor, but the upper limit sensor 9 is not limited to this, and the upper limit sensor 9 may be a sensor that detects the paper P using electromagnetic waves, infrared rays, or the like. good. The upper limit sensor 9 may be any one that detects an output signal obtained by inputting to the side of the paper bundle PT. Further, the follow-up control acquires and acquires the detection value of the floating upper limit sensor 9 of the paper P floated by the floating upper portion 6 for each sheet of paper conveyed by the conveying unit 8 during the paper feeding operation. The paper feed tray 2 may be raised when the detected value is less than the threshold value.

In the first to fourth embodiments described above, the transport unit 8 has been shown to suck and transport the paper P by the suction force of air suction, but the present invention is not limited to this, and the paper P is not limited to this, but the paper P is sucked by the suction force of electrostatic force or magnetic force. It may be configured to adsorb and convey.

In the first to fourth embodiments described above, the paper feeding device for feeding paper has been described, but the present invention can also be applied to a device for supplying sheets other than paper.

As described above, it goes without saying that the present invention includes various embodiments not described here. Therefore, the technical scope of the present invention is defined only by the matters specifying the invention relating to the reasonable claims from the above description.

[Additional Notes]
This application discloses the following inventions.

(Appendix 1)
An elevating loading platform on which a bundle of sheets is loaded, and a loading platform
A floating upper part that blows air onto the sheet bundle to raise the sheet of the sheet bundle, and
A transport unit that transports the highest-level sheet among the sheets floated by the floating top to the supply destination, and a transport unit.
A detector that detects an output signal obtained by inputting to the side of the sheet bundle, and
The floating portion and the transporting portion are controlled so as to transport the sheet to the supply destination, and for each sheet transported by the transporting portion, the detecting portion of the detecting portion during the floating of the sheet floated by the floating portion. It is provided with a control unit that acquires a detected value and performs follow-up control for raising the loading platform when the acquired detected value is less than a threshold value.
The control unit
When the empty transfer of the sheet by the transfer unit occurs, the floating upper portion and the transfer unit are controlled so as to perform a supply retry to redo the transfer of the sheet to the supply destination.
The sheet supply is characterized in that the threshold value is set so that the target position of the height position of the upper surface of the sheet bundle in the follow-up control is a position where blank feeding is more likely to occur than the double feeding of the sheets by the conveying unit. Device.

(Appendix 2)
An elevating loading platform on which a bundle of sheets is loaded, and a loading platform
A floating upper part that blows air onto the sheet bundle to raise the sheet of the sheet bundle,
A transport unit that transports the highest-level sheet among the sheets floated by the floating top to the supply destination, and a transport unit.
A detection unit that emits light from the side of the sheet bundle to the sheet bundle side and receives light from the sheet bundle side.
The floating upper portion and the conveying portion are controlled so as to convey the sheet to the supply destination, and for each sheet conveyed by the conveying portion, the detection portion of the detecting portion during the floating of the sheet floated by the floating upper portion. It is provided with a control unit that acquires a light receiving amount and performs follow-up control for raising the loading platform when the acquired light receiving amount is less than a threshold value.
The control unit
When the empty transfer of the sheet by the transfer unit occurs, the floating upper portion and the transfer unit are controlled so as to perform a supply retry to redo the transfer of the sheet to the supply destination.
The sheet supply is characterized in that the threshold value is set so that the target position of the height position of the upper surface of the sheet bundle in the follow-up control is a position where blank feeding is more likely to occur than the double feeding of the sheets by the conveying unit. Device.

(Appendix 3)
The control unit
When transporting at least one sheet, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is sampled, the threshold value is determined using the sampled light receiving amount, and the follow-up control is performed. It ’s something to start with.
When the sheet is fed by the transport unit until the threshold value is determined, the light receiving amount sampled at the time of the blank feeding is not adopted as the light receiving amount for determining the threshold value. The sheet supply device according to Appendix 2.

(Appendix 4)
The control unit
When transporting at least one sheet, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is sampled, the threshold value is determined using the sampled light receiving amount, and the follow-up control is performed. It ’s something to start with.
The sheet supply device according to Appendix 2, characterized in that a series of sheet supply operations are terminated without performing the supply retry when an empty sheet is fed by the transport unit until the threshold value is determined. ..

(Appendix 5)
The control unit is characterized in that, when the number of intermittent sheet feedings by the transport unit reaches a predetermined number of intermittent times during the execution of the follow-up control, the threshold value is increased by a predetermined amount. The sheet supply device according to any one of Supplementary note 2 to 4.

(Appendix 6)
The transport unit sucks and transports the sheet, and transports the sheet.
During the execution of the follow-up control, the control unit increases the threshold value by a predetermined amount when the number of intermittent sheet feedings by the transport unit reaches a predetermined number of intermittent feeds, and the transport unit. The sheet supply device according to any one of Supplementary Provisions 2 to 4, wherein at least one of the treatments for increasing the suction force of the sheet by the unit is performed.

(Appendix 7)
An elevating loading platform on which a bundle of sheets is loaded, and a loading platform
A floating upper part that blows air onto the sheet bundle to raise the sheet of the sheet bundle, and
A transport unit that adsorbs the highest sheet among the sheets floated by the floating top and transports it to the supply destination.
It is provided with a control unit that controls the floating upper portion and the transport unit so as to transport the sheet to the supply destination, and also performs follow-up control that raises the loading platform in response to a decrease in the number of sheets on the loading platform.
The control unit
When the empty transfer of the sheet by the transfer unit occurs, the floating upper portion and the transfer unit are controlled so as to perform a supply retry to redo the transfer of the sheet to the supply destination.
When the height position of the upper surface of the sheet bundle is at the target position in the follow-up control, the suction force of the sheet by the transfer section is such that the suction force is more likely to cause an empty feed than the double feed of the sheet. A seat feeder characterized by controlling.

(Appendix 8)
A detection unit that emits light from the side of the sheet bundle to the sheet bundle side and receives the light from the sheet bundle side is further provided.
The control unit
As the follow-up control, for each sheet transported by the transport unit, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is acquired, and when the acquired light receiving amount is less than the threshold value. Control to raise the loading platform,
Before starting the follow-up control, when transporting at least one sheet, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is sampled, and the sampled light receiving amount is used. It determines the threshold and
When the sheet is fed by the transport unit until the threshold value is determined, the light receiving amount sampled at the time of the blank feeding is not adopted as the light receiving amount for determining the threshold value. The sheet supply device according to Appendix 7.

(Appendix 9)
A detection unit that emits light from the side of the sheet bundle to the sheet bundle side and receives the light from the sheet bundle side is further provided.
The control unit
As the follow-up control, for each sheet transported by the transport unit, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is acquired, and when the acquired light receiving amount is less than the threshold value. Control to raise the loading platform,
Before starting the follow-up control, when transporting at least one sheet, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is sampled, and the sampled light receiving amount is used. It determines the threshold and
The sheet supply device according to Appendix 7, wherein when a sheet is empty-fed by the transport unit before the threshold value is determined, a series of sheet supply operations is terminated without performing the supply retry. ..

(Appendix 10)
A detection unit that emits light from the side of the sheet bundle to the sheet bundle side and receives the light from the sheet bundle side is further provided.
The control unit
As the follow-up control, for each sheet transported by the transport unit, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is acquired, and when the acquired light receiving amount is less than the threshold value. Control to raise the loading platform,
When the number of intermittent sheet feedings by the transporting unit reaches a predetermined number of intermittent feedings during the follow-up control, the processing of increasing the threshold value by a predetermined amount and the suction of the sheet by the transporting unit. The sheet supply device according to any one of Supplementary note 7 to 9, wherein at least one of the processes for increasing the force by a predetermined amount is performed.

(Appendix 11)
One of Supplementary Provisions 2 to 10, wherein the control unit forcibly raises the loading platform by a predetermined amount of increase when an empty sheet is fed by the transport unit during the execution of the follow-up control. The sheet feeder described in.

(Appendix 12)
11 is described in Appendix 11, wherein the control unit does not forcibly raise the loading platform until the empty feeding of the sheet by the transport unit is repeated a predetermined number of times during the execution of the follow-up control. Seat feeder.

(Appendix 13)
The appendix is characterized in that, when the number of consecutive blank feeds of the sheets by the transport unit reaches a predetermined number of times, the control unit terminates a series of sheet supply operations without performing the supply retry thereafter. The sheet supply device according to any one of 2 to 12.

1 Paper feed device 2 Paper feed stand 3 End fence 4 Lifting motor 5 Encoder 6 Floating top 7 Separation unit 8 Transport unit 9 Upper limit sensor 10 Paper feed roller 11 Paper feed motor 12 Paper feed inlet sensor 13 Control unit 16 Floating fan 17 Shutter 18 Separation fan 21 Conveyor belt 22 Drive roller 23 Driven roller 24 Conveyor motor 25 Suction mechanism 31 Light emitting part 32 Light receiving part 100 Printing device P paper PT Paper bundle

Claims (13)

An elevating loading platform on which a bundle of sheets is loaded, and a loading platform
A floating upper part that blows air onto the sheet bundle to raise the sheet of the sheet bundle, and
A transport unit that transports the highest-level sheet among the sheets floated by the floating top to the supply destination, and a transport unit.
A detector that detects an output signal obtained by inputting to the side of the sheet bundle, and
The floating portion and the transporting portion are controlled so as to transport the sheet to the supply destination, and for each sheet transported by the transporting portion, the detecting portion of the detecting portion during the floating of the sheet floated by the floating portion. It is provided with a control unit that acquires a detected value and performs follow-up control for raising the loading platform when the acquired detected value is less than a threshold value.
The control unit
When the empty transfer of the sheet by the transfer unit occurs, the floating upper portion and the transfer unit are controlled so as to perform a supply retry to redo the transfer of the sheet to the supply destination.
The sheet supply is characterized in that the threshold value is set so that the target position of the height position of the upper surface of the sheet bundle in the follow-up control is a position where blank feeding is more likely to occur than the double feeding of the sheets by the conveying unit. Device. An elevating loading platform on which a bundle of sheets is loaded, and a loading platform
A floating upper part that blows air onto the sheet bundle to raise the sheet of the sheet bundle,
A transport unit that transports the highest-level sheet among the sheets floated by the floating top to the supply destination, and a transport unit.
A detection unit that emits light from the side of the sheet bundle to the sheet bundle side and receives light from the sheet bundle side.
The floating upper portion and the conveying portion are controlled so as to convey the sheet to the supply destination, and for each sheet conveyed by the conveying portion, the detection portion of the detecting portion during the floating of the sheet floated by the floating upper portion. It is provided with a control unit that acquires a light receiving amount and performs follow-up control for raising the loading platform when the acquired light receiving amount is less than a threshold value.
The control unit
When the empty transfer of the sheet by the transfer unit occurs, the floating upper portion and the transfer unit are controlled so as to perform a supply retry to redo the transfer of the sheet to the supply destination.
The sheet supply is characterized in that the threshold value is set so that the target position of the height position of the upper surface of the sheet bundle in the follow-up control is a position where blank feeding is more likely to occur than the double feeding of the sheets by the conveying unit. Device. The control unit
When transporting at least one sheet, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is sampled, the threshold value is determined using the sampled light receiving amount, and the follow-up control is performed. It ’s something to start with.
When the sheet is fed by the transport unit until the threshold value is determined, the light receiving amount sampled at the time of the blank feeding is not adopted as the light receiving amount for determining the threshold value. The sheet supply device according to claim 2. The control unit
When transporting at least one sheet, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is sampled, the threshold value is determined using the sampled light receiving amount, and the follow-up control is performed. It ’s something to start with.
The sheet supply according to claim 2, wherein if a sheet is idlely fed by the transport unit before the threshold value is determined, a series of sheet supply operations are terminated without performing the supply retry. Device. The control unit is characterized in that, when the number of intermittent sheet feedings by the transport unit reaches a predetermined number of intermittent times during the execution of the follow-up control, the threshold value is increased by a predetermined amount. The sheet supply device according to any one of claims 2 to 4. The transport unit sucks and transports the sheet, and transports the sheet.
During the execution of the follow-up control, the control unit increases the threshold value by a predetermined amount when the number of intermittent sheet feedings by the transport unit reaches a predetermined number of intermittent feeds, and the transport unit. The sheet supply device according to any one of claims 2 to 4, wherein at least one of the processes of increasing the suction force of the sheet by the unit is performed. An elevating loading platform on which a bundle of sheets is loaded, and a loading platform
A floating upper part that blows air onto the sheet bundle to raise the sheet of the sheet bundle,
A transport unit that adsorbs the highest sheet among the sheets floated by the floating top and transports it to the supply destination.
It is provided with a control unit that controls the floating upper portion and the transport unit so as to transport the sheet to the supply destination, and also performs follow-up control that raises the loading platform in response to a decrease in the number of sheets on the loading platform.
The control unit
When the empty transfer of the sheet by the transfer unit occurs, the floating upper portion and the transfer unit are controlled so as to perform a supply retry to redo the transfer of the sheet to the supply destination.
When the height position of the upper surface of the sheet bundle is at the target position in the follow-up control, the suction force of the sheet by the transfer section is such that the suction force is more likely to cause an empty feed than the double feed of the sheet. A seat feeder characterized by controlling. A detection unit that emits light from the side of the sheet bundle to the sheet bundle side and receives the light from the sheet bundle side is further provided.
The control unit
As the follow-up control, for each sheet transported by the transport unit, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is acquired, and when the acquired light receiving amount is less than the threshold value. Control to raise the loading platform,
Before starting the follow-up control, when transporting at least one sheet, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is sampled, and the sampled light receiving amount is used. It determines the threshold and
When the sheet is fed by the transport unit until the threshold value is determined, the light receiving amount sampled at the time of the blank feeding is not adopted as the light receiving amount for determining the threshold value. The sheet supply device according to claim 7. A detection unit that emits light from the side of the sheet bundle to the sheet bundle side and receives the light from the sheet bundle side is further provided.
The control unit
As the follow-up control, for each sheet transported by the transport unit, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is acquired, and when the acquired light receiving amount is less than the threshold value. Control to raise the loading platform,
Before starting the follow-up control, when transporting at least one sheet, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is sampled, and the sampled light receiving amount is used. It determines the threshold and
The sheet supply according to claim 7, wherein if a sheet is idlely fed by the transport unit before the threshold value is determined, a series of sheet supply operations is terminated without performing the supply retry. Device. A detection unit that emits light from the side of the sheet bundle to the sheet bundle side and receives the light from the sheet bundle side is further provided.
The control unit
As the follow-up control, for each sheet transported by the transport unit, the light receiving amount of the detection unit during the floating of the sheet floated by the floating upper portion is acquired, and when the acquired light receiving amount is less than the threshold value. Control to raise the loading platform,
When the number of intermittent sheet feedings by the transporting unit reaches a predetermined number of intermittent feedings during the follow-up control, the processing of increasing the threshold value by a predetermined amount and the suction of the sheet by the transporting unit. The sheet supply device according to any one of claims 7 to 9, wherein at least one of the processes for increasing the force by a predetermined amount is performed. Any of claims 2 to 10, wherein the control unit forcibly raises the loading platform by a predetermined amount of increase when an empty sheet is fed by the transport unit during the execution of the follow-up control. The sheet supply device according to item 1. 15. The described sheet feeder. The claim is characterized in that when the number of consecutive blank feeds of the sheets by the transport unit reaches a predetermined number of times, the control unit terminates a series of sheet supply operations without performing the supply retry thereafter. Item 2. The sheet supply device according to any one of Items 2 to 12.

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