JP2019218179A - Feeder and printer - Google Patents

Abstract

To provide a feeder capable of properly detecting a separated state of stacked sheets with a comparatively simple structure.SOLUTION: A feeder comprises: stacking means for stacking a plurality of sheets; separating means for blowing air on the side portions of the plurality of sheets so as to facilitate separation of the plurality of sheets; light irradiation means for irradiating the side portions of the plurality of sheets with light; first light detecting means for detecting a reflected light from the side portions of the plurality of sheets; second light detecting means for detecting the reflected light and having a detection range larger than that of the first light detecting means; and switching means for switching the drive from one of the first light detecting means and the second light detecting means to the other.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a feeding device and a printer.

  Patent Document 1 discloses a feeding device that feeds a sheet to a printer, in which a plurality of sheets stacked in a sheet storage unit are blown with air to separate the plurality of sheets one by one so that the sheets can be fed. The configuration is described. Such a method is also called an air separation method (or an air blowing method, an air assist method, or the like). Further, according to Patent Document 1, by irradiating the side portions of the plurality of stacked sheets with light and detecting the reflected light with a predetermined sensor, the position of the separated sheet can be specified. I do.

JP 2014-201413 A

  By the way, various types of sheets, such as thin paper / thick paper, can be considered as sheets to be fed by the feeding device. Therefore, in the air separation method, a technique for appropriately detecting the separation state of such various types of sheets is required.

  An object of the present invention is to realize a configuration capable of appropriately detecting the separation state of stacked sheets with a relatively simple configuration.

  One aspect of the present invention relates to a feeding device, wherein the feeding device includes a stacking unit capable of stacking a plurality of sheets, and blowing air to a side portion of the plurality of sheets. Separating means for easily separating a plurality of sheets, light irradiating means for irradiating light to the side portions of the plurality of sheets, and a first device capable of detecting light reflected from the side portions of the plurality of sheets. Light detecting means, a second light detecting means configured to detect the reflected light and having a detection range larger than that of the first light detecting means, the first light detecting means, and the second light detecting means. Switching means for switching which one of the light detection means is to be driven.

  According to the present invention, it is possible to appropriately detect the separation state of the stacked sheets.

FIG. 2 is a schematic diagram illustrating a configuration example of a printer. FIG. 2 is a schematic diagram for describing a configuration example of a feeding device. FIG. 2 is a block diagram illustrating a system configuration example of a printer. FIG. 3 is a schematic diagram for describing a configuration example of a certain sheet storage unit in the feeding device. FIG. 7 is a diagram for explaining an example of a method for evaluating a separation mode of stacked sheets. FIG. 7 is a diagram for explaining an example of a method for evaluating a separation mode of stacked sheets. 5 is a flowchart for explaining an example of a control method of the feeding device. 5 is a flowchart for explaining an example of a control method of the feeding device. FIG. 7 is a diagram for explaining an example of a method for evaluating a separation mode of stacked sheets. FIG. 9 is a diagram for describing an example of an evaluation result of a separation mode of stacked sheets. FIG. 7 is a diagram for explaining an example of a method for evaluating a separation mode of stacked sheets. FIG. 7 is a diagram for explaining an example of a method for evaluating a separation mode of stacked sheets. FIG. 7 is a diagram for explaining an example of a method for evaluating a separation mode of stacked sheets.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Each drawing is merely a schematic diagram for the purpose of describing the structure or configuration, and the dimensions of each member illustrated do not necessarily reflect actual ones. In each drawing, the same members or the same components are denoted by the same reference numerals, and the description of the same content will be omitted below.

[First Embodiment]
FIG. 1 shows an example of the configuration of a printer (printing system) SY. The printer SY includes an image forming device 1, a feeding device 2, and a paper discharging device 3. The sheet feeding device 2 stores a plurality of sheets, and the image forming device 1 can form an image on a sheet supplied from the sheet feeding device 2 based on a print job received from the outside. It is. The paper discharge device 3 receives the sheet on which the image is formed from the image forming device 1 and outputs the sheet to the discharge tray 31. In the present embodiment, the image forming apparatus 1 includes the operation unit 11, and the user can generate electronic data using the operation unit 11 or transmit the electronic data to the outside. For example, a touch panel or the like may be used as the operation unit 11, but a button-type operation unit may be used.

  It is assumed that the concept of the printer SY includes an electronic device mainly having a printing function and an electronic device having a printing function as an auxiliary. For forming an image by the image forming apparatus 1, a known recording method such as a laser method and an ink jet method can be adopted. The concept of an image includes, for example, visually recognizable information such as characters, symbols, patterns, figures, pictures, photographs, and the like, as well as blanks (areas substantially the same as the ground color of the sheet of paper). A recording medium capable of forming an image may be used for the sheet.

  FIG. 2 is a schematic diagram illustrating an example of the internal configuration of the feeding device 2. In the present embodiment, the feeding device 2 includes a plurality of (three in this case) storage sections 2A to 2C, and each of the storage sections 2A to 2C can store a sheet. The following description focuses on a plurality of sheets (hereinafter, referred to as “stacked sheets SH”) stacked in the storage section 2A, but the same applies to the other storage sections 2B to 2C.

  FIG. 3 is a block diagram for explaining an example of the configuration of the storage section 2A. The accommodation section 2A includes a controller 21, an elevating mechanism 22 and its driver 22D, a transport mechanism 23 and its driver 23D, a separating mechanism 24 and its driver 24D, a sensor section 25, and a light source section 26.

  The controller 21 controls the driving of each element of the storage section 2A, and makes it possible to realize, for example, appropriate paper feeding to the image forming apparatus 1, although details will be described later. The controller 21 may be configured to be able to realize each function described below, and the function of the controller 21 can be realized by any of hardware and software. For example, the controller 21 may be configured by an ASIC (application-specific integrated circuit) or a PLD (programmable logic device).

  The elevating mechanism 22 receives power from the driver 22D and raises / lowers the loaded sheet SH so that conveyance of the sheet from the loaded sheet SH can be started. The transport mechanism 23 receives power from the driver 23D to pick up and transport a sheet from the stacked sheets SH. The separation mechanism 24 receives power from the driver 24D and separates the stacked sheets SH by receiving power from the driver 24D so that the sheets can be transported one by one (so as not to cause double feeding). A known electric motor such as a three-phase induction motor may be used for the drivers 22D, 23D and 24D.

  The sensor unit 25 includes two line sensors 251 and 252 in the present embodiment. The light source unit 26 irradiates light to a side portion of the stacking sheet SH, and the sensor unit 25 can detect light reflected from the side portion. Although the details will be described later, the sensor unit 25 and the light source unit 26 are used to evaluate the separation mode of the stacked sheets SH by the separation mechanism 24.

  With such a configuration, the controller 21 receives, for example, a command indicating the start of printing from the image forming apparatus 1 and drives each element of the storage unit 2A (or 2B or 2C) to transfer a sheet to the image forming apparatus 1. Supply. The image forming apparatus 1 transmits and receives signals to and from the paper discharge device 3, forms an image on the sheet supplied from the feeding device 2, and then places the sheet on the discharge tray 31 by the paper discharge device 3. Output.

  FIG. 4 is a schematic diagram illustrating an example of the internal structure of the storage section 2A. The storage section 2A includes a loading section 220 that can be raised and lowered as a part of the lifting mechanism 22. The stacking unit 220 is a plate member on which a plurality of sheets can be stacked, and may be expressed as a stacking unit, a bottom plate unit, or the like. Ascending / descending indicates movement of the device 2 in the vertical direction or the vertical direction, and may be expressed as vertical movement. The vertical direction corresponds to the sheet stacking direction of the stacked sheets SH. That is, the stacking unit 220 can change the position in the up-down direction according to the number (height) of the stacked sheets SH.

  The accommodation section 2A further includes a front regulation section 291, a rear regulation section 292, a side regulation section 293, and an upper regulation section 294 for regulating the position of the stacked sheets SH. The front regulation portion 291 regulates the end of each sheet of the stacked sheets SH on the downstream side in the sheet conveyance direction (the side in the direction following the sheet conveyance direction; hereinafter, may be simply referred to as “downstream side”). It may be expressed as an end regulating portion or the like. The rear regulating portion 292 regulates the end of each sheet of the stacked sheets SH on the upstream side in the sheet conveying direction (the side opposite to the sheet conveying direction; hereinafter, sometimes simply referred to as “upstream side”). It may be expressed as an upstream end regulating portion or the like. The rear regulating portion 292 can be configured to be movable in the sheet conveying direction. The side regulating portion 293 regulates the edge of each sheet of the stacked sheets SH on the side (the sheet width direction) crossing the sheet conveying direction, and may be expressed as a width direction regulating portion or the like. The side restricting portion 293 can be configured to be movable in the width direction of the sheet. The upper regulating unit 294 may regulate the stacking sheet SH by pressing it from above, and may be expressed as a pressing unit or the like.

  The accommodation section 2A includes a pickup roller 231 and a separation roller pair 232 as a part of the transport mechanism 23, and includes a blower fan 240 as a part of the separation mechanism 24. The fan 240 blows air to the side portions of the stacked sheets SH based on a control signal from the controller 21, thereby separating and separating the stacked sheets SH. Here, the side portion is a portion formed by the end or edge of each sheet in the stacked sheets SH. The separation mechanism 24 may be configured to be able to blow air to the side portion of the stacking sheet SH, and another blower or an air ejector such as a blower or a compressor may be used instead of the fan 240. .

  The pickup roller 231 picks up the uppermost one sheet from the stacked sheets SH separated by the blowing and starts conveying the sheet. When two or more sheets are picked up by the pickup roller 231, the separation roller pair 232 can separate them. For example, by controlling the respective rotation directions of the separation roller pair 232, one of the two or more sheets is conveyed to the downstream side, and the remaining sheets are returned to the upstream side (to the stacked sheets SH). It will be. As illustrated in FIG. 2, the storage unit 2A further includes a transport roller 233 as a part of the transport mechanism 23. The paper is conveyed to the image forming apparatus 1 through a path.

  Although details will be described later, as shown in FIG. 4, the line sensors 251 and 252 of the sensor unit 25 are fixed in a posture facing the side portion of the stacking sheet SH, and The reflected light from the side can be detected.

  FIG. 5 is a diagram for explaining an example of an evaluation method for the separation mode of the stacked sheets SH separated by the above-described air blowing. This separation mode indicates whether or not the stacked sheets SH are easily separated, or more strictly, whether or not the stacked sheets SH are separated to such an extent that the sheets can be conveyed one by one. This is performed by the controller 21 using the sensor unit 25 and the light source unit 26. In the present embodiment, the above evaluation is performed based on the sheet density in a predetermined region of the stacked sheets SH, for example, whether the gap (gap) is large or small, whether the gap (gap between sheets) is large or small, and the like.

  In the present embodiment, the sensor unit 25 acquires a sensor value for each of a plurality of regions obtained by dividing the side portion of the stacking sheet SH by a predetermined width unit in the vertical direction. For example, since the amount of reflected light increases from an area where the stacked sheets SH are dense (an area where separation is difficult), the sensor value of the sensor unit 25 indicating the detection result of the reflected light increases. Further, for example, since the amount of reflected light is small from a region where the stacking sheet SH is sparse (a region where separation is easy), the sensor value of the sensor unit 25 indicating the detection result of the reflected light is small. Although details will be described later, the controller 21 generates an evaluation value indicating the ease of separation of the stacked sheets SH based on the sensor values thus obtained.

  Here, the width of the region to be evaluated (the width in the up-down direction) is variable, and this is realized using two line sensors 251 and 252 in the present embodiment.

  FIG. 6A shows an example in which the first line sensor 251 is used as one aspect of the above-described evaluation method, and FIG. 6B shows another example of the above-mentioned evaluation method. An example in which the two-line sensor 252 is used will be described. The line sensor 251 includes a plurality (five in this case) of sensors S11 to S15 arranged in the vertical direction. Further, the line sensor 252 includes a plurality (five in this case) of sensors S21 to S25 vertically arranged at a position different from the line sensor 251 / at a position separated from the line sensor 251.

  The detection range of the reflected light for each of the sensors S11 to S15 is defined as a range DR1, and the detection range of the reflected light for each of the sensors S21 to S25 is defined as a range DR2. The width (width in the vertical direction) of the detection range DR2 is larger than the detection range DR1. For example, each of the sensors S11 to S15 acquires a sensor value corresponding to the light amount in the detection range DR1 and outputs the sensor value to the controller 21. Similarly, each of the sensors S21 to S25 acquires a sensor value corresponding to the light amount in the detection range DR2, and outputs the sensor value to the controller 21.

  As each of the sensors (S11 and the like), a CCD / CMOS image sensor including a photoelectric conversion element such as a photodiode and a switch element such as a transistor can be used. In this case, the detection range DR1 or DR2 corresponds to a range in which the photoelectric conversion element can detect light. Additionally, each sensor is provided with an optical system, such as a rod lens, for condensing the reflected light from the side portion of the stacking sheet SH and guiding it to the photoelectric conversion element. In this case, the detection range DR1 or DR2 corresponds to a range in which the optical system can collect light.

  FIG. 7 is a flowchart illustrating a control method of the feeding device 2. The outline of this control method is to separate the stacked sheets SH in accordance with the type of the sheet, and then to feed the sheet. The content of each step can be mainly executed by the controller 21. The present control method can be started, for example, in response to the apparatus 2 receiving a print job. However, steps before the execution of sheet feeding may be performed, for example, in a predetermined cycle, It may be started in response to activation (power ON). In the following, for ease of explanation, two types of sheets, thin paper and thick paper, will be described as examples of sheets, but the present invention is not limited to these examples.

  In step S110 (hereinafter, simply referred to as “S110”; the same applies to other steps described later), the position of the stacking unit 220 is determined. S110 is performed based on the number (height) of the stacked sheets SH, for example, based on the pressure applied to the upper regulating unit 294. Thus, the position of the stacking unit 220 can be adjusted such that the uppermost one of the stacked sheets SH can be picked up by the pickup roller 231.

  In S120, the thin paper detection mode is set as the initial setting of the operation mode. In the present embodiment, in S120, in the sensor unit 25, the line sensor 251 is set to the enable state (operable state / detectable state), and the line sensor 252 is set to the disable state (pause state).

  In S130, the fan 240 is driven to blow air to the side portions of the stacked sheets SH to separate the stacked sheets SH. Although details will be described later, in S140, it is determined whether or not it is necessary to change the operation mode based on the evaluation result of the separation mode of the stacked sheets SH by the blowing. If the operation mode needs to be changed, the process proceeds to S150; otherwise, the process proceeds to S160. In S150, the operation mode is changed to the thick paper detection mode, and the process proceeds to S160.

  In S160, it is determined whether the paper feed preparation has been completed. This determination is made based on the evaluation result of the separation mode of the stacked sheets SH, similarly to S140. If the stacked sheets SH are not properly separated, it is determined that the sheet feeding preparation is not completed, and the process proceeds to S170. If the stacked sheets SH are properly separated, it is determined that the sheet feeding preparation is completed. Proceed to S180. In S170, although the details will be described later, the flow rate of the fan 240 is changed, and the process returns to S160.

  In step S180, sheet feeding is performed, that is, the pickup roller 231, the separation roller pair 232, and the transport roller 233 are driven to supply one sheet from the stacked sheets SH to the image forming apparatus 1.

  FIG. 8 is a flowchart showing details of the contents of S130 to S170. In S1310, in the thin paper detection mode, the air blowing amount of the fan 240 is set to the reference value, and air is blown to the side portion of the stacked sheets SH. This reference value may be a relatively large fixed value, or may be the maximum air volume.

  In S1410, the detection result of the line sensor 251 is acquired for the side portion of the stacked sheets SH to which the air has been blown (see FIGS. 5 and 6A).

In S1420, the separation mode of the stacked sheets SH is evaluated based on the detection result obtained in S1410, and it is determined whether the stacked sheets SH can be separated. When the sensor value obtained from the sensor S11~S15 of the line sensor 251 was a sensor value _V S11 _{~V S15} respectively, evaluation value E1 indicating the ease of separation of the stacked sheets SH are, for example,
E1 = Σ (V _REF1 −V _S1k ) × a,
V _REF1 : reference value for evaluation,
k: an integer of 1 to 5,
a: coefficient (a> 0),
Given by The reference value V _REF1 is a value that is set in advance by a test or the like as an index indicating the separation state of the stacked sheets SH that can appropriately perform sheet feeding.

When the evaluation value E1 falls within the allowable range, for example,
E1 ≧ E _min ,
E _min : allowable lower limit,
Is satisfied, it can be said that the stacked sheets SH have been appropriately separated (the sheet feeding can be performed). On the other hand, when E1 <E _min , it can be said that the stacked sheets SH are not sufficiently separated, and, for example, a double feed may occur.

  If it is determined in the above procedure that the stacked sheets SH can be separated, the process proceeds to S1430; otherwise, the process proceeds to S1510. Note that the ease of separation of the stacked sheets SH varies depending on the device environment (temperature, humidity, etc. in the storage section 2A), and thus the coefficient a may be set based on the device environment.

In S1430, one of the sensor values _V S11 _{~V S15} determines whether a predetermined condition is satisfied. Here, prior to description of the method of determining S1430, FIG. 9 (A), the FIG. 9 (B) and with reference to FIG. 10 the sensor value _V S11 _{~V S15} will be described.

FIG. 9A illustrates one mode for describing a detection result obtained by the sensor array 251. In the drawing, for the sake of distinction, the detection ranges of the sensors S11 to S15 of the sensor array 251 are shown as ranges DR1 _{S11 to} DR1 _S15 , respectively, but in the following description, if these are not particularly distinguished, they are simply referred to as the detection range DR1. Express. In this example, each sheet of the stacked sheets SH is a relatively thin thin (thickness T1), the width (diameter in the figure) of the detection range DR1 R _DR1 is made larger than the thickness T1.

When the area where the detection range DR1 and the sheet overlap increases, the amount of reflected light increases and the sensor value increases. For example, in the detection range DR1 _{S11, since} there is no overlap with the sheet, the sensor value becomes the minimum value (the signal component becomes substantially zero). On the other hand, for example, in the detection range DR1 _{S12, since} there is an overlap with the two sheets, the sensor value is relatively large (there is a signal component).

FIG. 9B is another mode for describing a detection result by the sensor array 251. In this example, the sheet is thicker than the example of FIG. 9A (thickness T2), and the width R _DR1 of the detection range _DR1 is smaller than the thickness T2. In this case, in the detection ranges DR1 _S12 and DR1 _S14 , since the whole of them overlaps with the sheet, their sensor values substantially take the maximum value (the maximum value in the specification).

FIG. 10 shows a detection result of the line sensor 251 according to the example of FIGS. 9A and 9B. The horizontal axis shows the numbers of the sensors S11 to S15, and the vertical axis shows the sensor values. In the drawing, sensor values VS11 to VS15 corresponding to sensors _{S11 to S15} are plotted for thin paper (see FIG. 9A) and for thick paper (see FIG. 9B), respectively. . In the case of thick paper, it can be seen that the sensor values _VS12 and _VS14 have substantially the maximum values. This indicates a state in which a single thick paper exists in each of the detection ranges DR1 _S12 and DR1 _S14. However, it is difficult to distinguish from a state in which a plurality of thin papers are in close contact with each other. Depending on the method, it can be said that it is difficult to appropriately evaluate the separation mode of the stacked sheets SH.

Therefore, in S1430, among the sensor values _V S11 _{~V S15,} when an indication that the amount of reflected light from the side portion of the stacked sheets SH was greatest substantially takes the maximum value, the process proceeds to S1510, Otherwise, the process proceeds to S1610.

In S1610, it is determined whether or not the fan 240 needs to change the blowing amount. The determination in S1610 may be made based on the evaluation result of the separation mode of the stacked sheets SH, as in S1420. When the evaluation value E1 is out of the allowable range, for example,
E1> E _MAX ,
E _MAX : allowable upper limit,
Is satisfied, it can be said that the stacked sheets SH are excessively separated, that is, the amount of air blown by the fan 240 is too large. Therefore, in this case, it is determined that the air flow needs to be changed. In such a procedure, when it is determined that the air flow needs to be changed, the process proceeds to S1710, and otherwise, the process proceeds to S1720.

  In S1710, the amount of air blown by the fan 240 is changed. In the present embodiment, since it is determined in S1610 that the amount of air blown by the fan 240 is too large, for example, the air blow level is reduced by one level. After the change of the blowing amount, the process returns to S1610 again.

  In S1720, the air flow rate is determined to be the one determined in S1610, the flow chart ends, and the flow proceeds to S180 (see FIG. 7).

  In S1510, in the thick paper detection mode, the amount of air blown by the fan 240 is set to a reference value, and air is blown to the side of the stacked sheets SH. This reference value may be equal to the reference value in S1310, but may be a fixed value larger than the reference value, or may be the maximum airflow.

  In S1520, the detection result of the line sensor 252 is acquired for the side portion of the stacking sheet SH to which the air has been blown by the same procedure as in S1410 (see FIGS. 5 and 6B).

  In S1530, in the same procedure as in S1420, the separation mode of the stacked sheets SH is evaluated based on the detection result obtained in S1520, and it is determined whether the stacked sheets SH can be separated.

FIG. 9C illustrates one mode for describing a detection result obtained by the sensor array 252. In the drawing, for the sake of distinction, the detection ranges of the sensors _{S21 to S25 of} the sensor array 252 are shown as ranges DR1 _{S21 to} DR1 _S25 , respectively (when these are not particularly distinguished, they are simply referred to as detection ranges DR2). It is assumed that the width (diameter in the drawing) R _DR2 of the detection range DR2 is smaller than the thickness T2. According to the sensor array 252, any of the detection ranges DR1 _{S21 to} DR1 _S25 does not entirely overlap the sheet, so that the separation state of the stacked sheets SH can be appropriately evaluated.

When the sensor values obtained from the sensors _{S21 to S25} are sensor values VS21 to VS25, respectively, the evaluation value E2 indicating the ease of separation of the stacked sheets SH is, for example,
E2 = Σ (V _REF2 −V _S2k ) × b,
V _REF2 : reference value for evaluation,
k: an integer of 1 to 5,
b: coefficient (b> 0),
Given by Like the reference value V _REF1 , the reference value V _REF2 is a value set in advance as an index indicating the separation state of the stacked sheets SH that can appropriately execute sheet feeding. Further, the coefficient b may be set based on the device environment, similarly to the coefficient a.

  If it is determined in S1530 that the stacked sheets SH can be separated, the process proceeds to S1620; otherwise, the process proceeds to S1630.

  The contents of S1620, S1730, and S1740 are the same as the contents of S1610, S1710, and S1720, and a description thereof will not be repeated.

  In step S1630, the user is notified that the stacked sheets SH cannot be separated, and the user is prompted to confirm the storage unit 2A, for example, whether an unexpected sheet or another object is stacked. This notification may be performed by displaying it on a predetermined display unit on the operation unit 11 (see FIG. 1), or may be performed by generating an alarm sound incidentally / alternatively.

  As described above, in the present embodiment, air is blown to the side portion of the stacked sheets SH using the fan 240 so that the sheets can be appropriately conveyed one by one from the stacked sheets SH (to prevent double feeding from occurring). 2) to facilitate separation of the stacked sheets SH. The controller 21 detects the separation mode of a predetermined area in the side portion of the stacking sheet SH using the sensor unit 25 and the light source unit 26, and evaluates whether or not the stacking sheet SH can be appropriately separated. In the present embodiment, the sensor unit 25 includes line sensors 251 and 252 that can detect reflected light from the side of the stacking sheet SH irradiated by the light source unit 26, and the detection range of the line sensor 252 is line. It is configured to be larger than the sensor 251. The controller 21 switches the line sensor 251 or 252 to be driven to change the width (the vertical width) of the region to be evaluated for the separation mode.

  In the present embodiment, the controller 21 drives the line sensor 251 in the thin paper detection mode to evaluate the separation mode of the side portion of the stacked sheet SH, and drives the line sensor 252 in the thick paper detection mode to drive the stacked sheet SH. The mode of separation of the side portions of the SH is evaluated. That is, when the sheet is thin paper, the controller 21 evaluates the separation mode in a relatively narrow area, and when the sheet is thick paper, the controller 21 evaluates the separation mode in a relatively wide area. In other words, the controller 21 forms, together with the sensor unit 25 and the light source unit 26, an evaluation unit that evaluates a separation mode of a predetermined region among the side portions of the stacking sheet SH. Which area is to be evaluated can be changed by the controller 21.

  The controller 21 generates an evaluation value indicating the ease of separation of the stacked sheets SH by evaluating the separation mode. The evaluation value follows the detection result of the reflected light from the side of the stacking sheet SH, that is, the sensor value obtained by the sensor unit 25. In the present embodiment, when the stacked sheets SH are sparse (the gap is relatively large / large and the separation of the sheets is relatively easy), the amount of reflected light is small and the sensor value is small. On the other hand, when the stacked sheets SH are dense (the gap is relatively small / small, and the separation of the sheets is relatively difficult), the amount of reflected light increases and the sensor value increases. The evaluation value is generated based on the sensor value thus obtained. The controller 21 switches which of the line sensors 251 and 252 should be driven based on the evaluation value (S140 to S150), and controls the amount of air blown by the fan 240 to prepare for sheet feeding (S160 to S170). ).

  In the present embodiment, thin paper is shown as an example of a sheet that is easy to be separated, and thick paper is shown as an example of a sheet that is difficult to be separated. However, the type of sheet is not limited to these examples. That is, the contents of the present embodiment can be applied to, for example, two types of sheets having different paper qualities / materials. Further, in the present embodiment, two types of sheets of thin paper and thick paper are illustrated for the sake of simplicity of description, but three or more types of sheets may be used.

  As described above, according to the present embodiment, it is possible to appropriately detect the separation state of various types of sheets, and to determine whether or not the stacked sheets SH are properly separated so as to be able to feed paper. Can be determined according to

[Second embodiment]
In the first embodiment described above, the line sensors 251 and 252 are switched to change the width of the area to be evaluated for the separation mode of the stacked sheets SH. However, the present invention is not limited to this method. In the second embodiment, the above evaluation is performed by using a single line sensor whose detection range can be changed instead of the line sensors 251 and 252, and the same effect as in the first embodiment can be obtained by such a method. can get.

  FIG. 11A shows an embodiment in which a single line sensor 251 ′ is used as the sensor unit 25. The line sensor 251 'includes a plurality (ten in this case) of sensors S11 to S20 arranged in the vertical direction. The controller 21 is capable of independently controlling the upper part (here, the sensors S11 to S15) and the remaining part (here, the sensors S16 to S20) of the sensors S11 to S20. In the present embodiment, by using the enable signals IE1 and IE2, the driving of the sensors S11 to S20 and the suppression thereof can be controlled.

  In the present embodiment, the sensors S11 to S15 can be controlled to be enabled or disabled by the enable signal IE1. The sensors S16 to S20 can be controlled to be enabled or disabled by the enable signal IE2. For example, in the thin paper detection mode, the enable signal IE1 is set to the activation level (for example, high level) and the enable signal IE2 is set to the inactivation level (for example, low level). Thus, the sensors S11 to S15 can be enabled and the sensors S16 to S20 can be disabled. In the thick paper detection mode, all of the sensors S11 to S20 can be enabled by setting both the enable signals IE1 and IE2 to the activation level. According to the present embodiment, the same effects as those of the first embodiment can be obtained, and the number of components of the sensor unit 25 can be reduced.

Each detection range of the sensors S11 to S20 is equivalent to the detection range DR1 of the first embodiment, and is relatively narrow. In this case, the change of the operation mode (see S140 in FIG. 7) is substantially the maximum of two or more consecutive sensor values VS11 to VS15 of the sensors _{S11 to S15} which are enabled in the thin paper detection mode. It only needs to be executed when taking a value.

  Since the sensor unit 25 only needs to be configured so that the detection range can be changed, a single sensor that can change the detection range may be used instead of the line sensor 251 '. The same effect as in the first embodiment can be obtained by such a method.

  FIGS. 11B1 and 11B2 illustrate an embodiment in which a single sensor 253 is used as the sensor unit 25. FIG. FIG. 11 (B1) shows a detection range DRa of the sensor 253 corresponding to the thin paper detection mode, and FIG. 11 (B2) shows a detection range DRb of the sensor 253 corresponding to the thick paper detection mode. That is, the controller 21 can switch the detection range of the sensor 253 to one of the ranges DRa and DRb according to the operation mode. An example of the sensor 253 is a scanning radar. In this case, the sensor 253 only needs to acquire data (signal group) indicating the light amount distribution of the reflected light from the stacking sheet SH.

[Third embodiment]
The method of making the width of the region to be evaluated for the separation mode of the stacked sheets SH variable is not limited to the above-described first and second embodiments. In the third embodiment, the above-described evaluation is performed by allowing the irradiation range of the light source unit 26 to be changed, and the same effect as in the first and second embodiments can be obtained by such a method.

  FIG. 12A shows an irradiation range IR1 of the light source unit 26 corresponding to the thin paper detection mode, and FIG. 12B shows an irradiation range IR2 of the light source unit 26 corresponding to the thick paper detection mode. That is, the controller 21 can switch the irradiation range of the light source unit 26 to one of the ranges IR1 and IR2 according to the operation mode.

  In the present embodiment, a line sensor 251 ′ (see the second embodiment) is used as the sensor unit 25. In the thin paper detection mode, if the upper part (here, sensors S11 to S15) of the sensors S11 to S20 of the line sensor 251 'is enabled, the remaining part (sensors S16 to S20) is disabled. Good. In the thick paper detection mode, all of the sensors S11 to S20 may be enabled.

  In this embodiment, the line sensor 251 'is used as the sensor unit 25. However, as another embodiment, line sensors 251 and 252 (see the first embodiment) are used instead of the line sensor 251'. May be used.

  The same applies to the first and second embodiments. In particular, in the present embodiment, the light source unit 26 is provided with a directivity so that the light amount distribution becomes uniform over the entire irradiation range IR1 or IR2. A high light source may be used. For example, one or more LED elements may be used for the light source unit 26, and a rod-shaped light guide may be additionally used. The light source unit 26 may be driven by so-called automatic light control (APC (Auto Power Control)) so that the light amount does not change due to switching of the irradiation range.

  In the present embodiment, the irradiation range can be switched using the single light source unit 26. However, as another embodiment, the irradiation range is switched using two light source units having different irradiation ranges. Is also possible.

[Fourth embodiment]
As some examples of the method of making the width of the area to be evaluated for the separation mode of the stacked sheets SH variable, the detection range of the sensor unit 25 can be changed in the first and second embodiments described above. In the third embodiment, it has been described that the irradiation range of the light source unit 26 can be changed. However, the area to be evaluated can be made variable by another method. In the fourth embodiment, the detection range of the sensor unit 25 and the irradiation range of the light source unit 26 are fixed regardless of the operation mode (in either the thin paper detection mode or the thick paper detection mode). The contents can be changed according to the operation mode. That is, in the present embodiment, the controller 21 can select which part of the group of sensor values obtained from the sensor unit 25 to use in generating the evaluation value.

In the present embodiment, a line sensor 251 ′ (see the second embodiment) is used as the sensor unit 25. The controller 21 receives the sensor values VS11 to VS20 from the sensors _{S11 to S20} of the line sensor 251 'regardless of the operation mode. Then, the controller 21, the thin paper detection mode refers to the sensor value _V S11 _{~V S15} of sensor values _V S11 _{~V S20,} to evaluate the separation aspect of the stacked sheets SH. On the other hand, the controller 21, in the thick paper detection mode refers to the whole of the sensor value _V S11 _{~V S20,} to evaluate the separation aspect of the stacked sheets SH.

This embodiment can be easily realized by using a general-purpose computer that includes a CPU (Central Processing Unit) 211, a memory 212, and an external communication interface 213 and performs signal processing based on a program as the controller 21. In this case, the function of the controller 21 is realized by software, but can also be realized by hardware. For example, as another embodiment, the controller 21 generates a selector and an evaluation value based on the selected part / whole of selecting a part / all of the sensor values V _S11 ~V _S20 in accordance with the operation mode And a processor that performs the processing.

  In the above embodiments, some preferred aspects have been exemplified. However, it is needless to say that the present invention is not limited to these, and may be partially modified or combined without departing from the spirit of the present invention. Is also good. Further, individual terms described in this specification are merely used for describing the present invention, and it is needless to say that the present invention is not limited to the strict meaning of the terms. It may also include its equivalents.

  2: feeding device, 21: controller, 220: loading unit, 240: blower fan, 25: sensor unit, 251: line sensor, 252: line sensor, 26: light source unit.

Claims (13)

Loading means capable of loading a plurality of sheets,
Separating means for blowing the side portions of the plurality of sheets to easily separate the plurality of sheets,
Light irradiation means for irradiating the side portions of the plurality of sheets with light,
First light detection means capable of detecting reflected light from the side portions of the plurality of sheets,
A second light detection unit configured to be capable of detecting the reflected light and having a detection range larger than the first light detection unit;
A feeding unit comprising: a switching unit that can switch which of the first light detecting unit and the second light detecting unit is driven. The first light detection unit includes a plurality of first sensors arranged in a sheet stacking direction,
The feeding device according to claim 1, wherein the second light detection unit includes a plurality of second sensors arranged in the sheet stacking direction at positions different from the plurality of first sensors. The feeding device according to claim 2, wherein a width of each of the second sensors in the sheet stacking direction in a detection range of the reflected light is larger than each of the first sensors. The switching unit drives the first light detection unit when each of the plurality of sheets has the first thickness, and the second unit has a second thickness larger than the first thickness. In the case of the thickness, the second light detection means is driven,
The detection range of the reflected light of each first sensor is larger than the first thickness and smaller than the second thickness,
4. The feeding device according to claim 2, wherein a detection range of the reflected light of each second sensor is larger than the second thickness. 5. The switching unit drives the first light detection unit when each of the plurality of sheets has the first thickness, and the second unit has a second thickness larger than the first thickness. The feeding device according to any one of claims 1 to 4, wherein the second light detection unit is driven when the thickness is equal to the thickness. Control means for controlling an amount of the air blown by the separation means based on a detection result by the first light detection means or the second light detection means. The apparatus according to claim 1, further comprising: Item 6. A feeding device according to any one of Items 5. Loading means capable of loading a plurality of sheets,
Separating means for blowing the side portions of the plurality of sheets to easily separate the plurality of sheets,
Light irradiation means for irradiating the side portions of the plurality of sheets with light,
Light detection means capable of detecting reflected light from the side portions of the plurality of sheets,
The sheet feeding device, wherein the light detecting unit is capable of changing a width of an area where light reflected from the side part in the sheet stacking direction can be detected. The feeding device according to claim 7, further comprising: a control unit that controls an amount of the air blown by the separation unit based on a detection result by the light detection unit. The light detection unit includes a first sensor and a second sensor having different widths in the sheet stacking direction with respect to the detection range of the reflected light,
The feeding device further includes a generation unit configured to generate an evaluation value indicating the ease of separation of the plurality of sheets based on a signal from one of the first sensor and the second sensor. The feeding device according to claim 8. The light detecting means changes a width of an area where the light detecting means can detect reflected light from the side portion in a sheet stacking direction based on a thickness of each of the plurality of sheets. The feeding device according to claim 9, wherein The light detection unit includes a line sensor extending in the sheet stacking direction,
The feeding device according to claim 8, wherein the light detection unit can select which part of a signal group obtained by the line sensor is to be a detection result. Loading means capable of loading a plurality of sheets,
Separating means for blowing the side portions of the plurality of sheets to easily separate the plurality of sheets,
Light irradiation means for irradiating the side portions of the plurality of sheets with light,
Light detection means capable of detecting reflected light from the side portions of the plurality of sheets as a plurality of signal groups,
A control unit that controls any amount of the air blown by the separation unit based on the detection result, using any part of the plurality of signal groups detected by the light detection unit as a detection result,
A feeding device comprising: A feeding device according to any one of claims 1 to 12,
An image forming system, comprising: an image forming apparatus that forms an image on a sheet supplied from the feeding device.