Medium feeding device and control method thereof

Abstract

To improve stability in feeding media from a media group placement part.SOLUTION: A media feeding device includes a pickup unit that includes a placement part on which media groups are placed, a lifting part that raises and lowers the placement part, a pickup roller that contacts the top of the media groups, and a support part that applies downward force to the pickup roller, and feeds media in a feeding direction from top to bottom while applying downward pressing force from the pickup roller to the media groups; a control part; and a detection part that detects the pressing force. The control part causes the lifting part to raise and lower the placement part so that the detected pressing force falls within a target range.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a medium feeding device that feeds a medium in a feeding direction from a group of media placed on a liftable placement unit, and a control method therefor.

Background Art

[0002] As a medium feeding device, Patent Document 1 discloses a sheet feeding device for an image reading device. The sheet feeding device includes a platen, a platen drive motor that raises and lowers the platen, a pick roller that feeds a document from the platen in the paper feeding direction, a document separation and feeding unit including a feed roller and a separation roller, a control unit that changes the separation torque of the separation motor, and the like. The control unit changes the separation torque according to the deflection rate by utilizing the fact that the deflection rate of the document bundle due to the lowering of the pick roller varies depending on the type of document.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the feeding of the document from the pick roller to the document separation and feeding unit may become unstable, and a jam (paper jam) may occur, such that the document gets stuck in the document separation and feeding unit or the like and the feeding operation stops. In addition, the above problems can also be considered in devices other than image reading devices, such as recording devices.

Means for Solving the Problems

[0005] The medium feeding device of the present invention includes a placement unit on which a group of media is placed, a lifting unit that raises and lowers the placement unit, A pick roller that contacts the upper part of the media group, and a support part that applies a downward force to the pick roller, including a pick unit that feeds the media in the feeding direction in order from above while applying a downward pressing force from the pick roller to the media group. A control unit, A detection unit that detects the pressing force, and is provided with The control unit has an aspect of raising and lowering the placement unit in the elevating unit so that the detected pressing force falls within a target range.

[0006] In addition, a control method for a media feeding device according to the present invention is A placement unit on which a media group is placed, An elevating unit that raises and lowers the placement unit, A pick roller that contacts the upper part of the media group, and a support part that applies a downward force to the pick roller, including a pick unit that feeds the media in the feeding direction in order from above while applying a downward pressing force from the pick roller to the media group, and is a control method for a media feeding device provided with A detection step of detecting the pressing force, An elevating control step of raising and lowering the placement unit in the elevating unit so that the detected pressing force falls within a target range, and has an aspect including

Brief Description of the Drawings

[0007]

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[0008] Hereinafter, embodiments of the present invention will be described. Of course, the following embodiments are merely illustrative of the present invention, and not all of the features shown in the embodiments are necessarily essential to the solution means of the invention.

[0009] (1) Outline of the aspects included in the present invention: First, an outline of the aspects included in the present invention will be described with reference to the examples shown in FIGS. 1 to 15. Note that the drawings in the present application are diagrams schematically showing examples, and the magnification ratios in each direction shown in these drawings may be different, and the drawings may not be consistent. Of course, each element of this aspect is not limited to the specific examples indicated by the reference numerals. In the "outline of the aspects included in the present invention", the content in parentheses means a supplementary explanation of the immediately preceding word. Also, in the present application, the numerical range "Min~Max" means greater than or equal to the minimum value Min and less than or equal to the maximum value Max.

[0010] [Aspect 1] As shown in FIGS. 1 to 3 and the like, a medium feeding device 3 according to one aspect includes a placement unit 10 on which a medium group G1 is placed, a lifting unit 20 that raises and lowers the placement unit 10, a pick unit 30, a control unit 90, and a detection unit 40. The pick unit 30 includes a pick roller 31 that contacts the upper part G1a of the medium group G1, and a support unit 32 that applies a downward force to the pick roller 31. The medium ME1 is fed in the feeding direction D1 in order from above while applying a downward pressing force F0 from the pick roller 31 to the medium group G1. The detection unit 40 detects the pressing force F0. The control unit 90 raises and lowers the placement unit 10 with respect to the lifting unit 20 so that the detected pressing force F0 falls within a target range (for example, Ft - ΔFt to Ft + ΔFt).

[0011] When investigating the reason why the feeding of the document from the pick roller 31 to the document separation and feeding unit becomes unstable, it was found that the pressing force F0 applied from the pick roller 31 to the medium group G1 changes greatly. In the above aspect 1, the medium ME1 is fed in order from above from the placement unit 10 in a state where the pressing force F0 of the pick roller 31 is within the target range. Therefore, the above aspect 1 can provide a medium feeding device capable of improving the stability of feeding the medium from the placement unit of the medium group. As a result, the occurrence of jams can be suppressed.

[0012] Various examples can be cited for the above-described aspect. The medium feeding device may be provided in an image reading device including a medium reading unit, or may be provided in a recording device or the like including a recording unit that performs recording on the medium. Examples of the medium include a document having a document image, printing paper, and the like. The material of the medium is not limited to paper, and may be resin, metal, or the like. Of course, the above-mentioned remarks are also applicable in the following aspects.

[0013] [Aspect 2] As shown in FIG. 2, the detection unit 40 may include a force sensor 41 using a crystal, and the pressing force F0 may be detected by the force sensor 41. In the above case, since the pressing force F0 of the pick roller 31 can be accurately maintained, the stability of feeding the medium from the placement part can be further improved. Although not included in the above-described aspect 2, the detection unit may detect the pressing force by an electrostatic capacitance type force sensor or the like.

[0014] [Aspect 3] As illustrated in FIG. 4, the control unit 90 may be capable of receiving an instruction to start feeding the medium ME1. When the control unit 90 receives the feeding start instruction, the control unit 90 raises the placement unit 10 by the elevating unit 20, and rotates the pick roller 31 so that the medium ME1 is fed in the feeding direction D1 when the pressing force F0 detected by the detection unit 40 falls within the target range (for example, Ft - ΔFt to Ft + ΔFt). In the above case, since the feeding of the medium ME1 is started after the pressing force F0 of the pick roller 31 falls within the target range, the stability of feeding the medium from the placement part after the start of feeding can be improved.

[0015] [Aspect 4] As illustrated in FIG. 13, the medium feeding device 3 may further include a medium storage unit 210 in which the placement unit 10 is disposed, a mounting unit 220 to which the medium storage unit 210 can be mounted at a use position, and a mounting detection unit 230 that detects whether the medium storage unit 210 is mounted on the mounting unit 220. As illustrated in FIG. 14, when the mounting detection unit 230 detects the mounting of the medium storage unit 210, the control unit 90 may raise the placement unit 10 by the elevating unit 20 so that the pressing force F0 detected by the detection unit 40 falls within the target range (for example, Ft - ΔFt to Ft + ΔFt). In the above case, since the pressing force F0 of the pick roller 31 falls within the target range when the medium storage unit 210 is mounted on the mounting unit 220, the stability of feeding the medium from the placement part after the mounting of the medium storage unit 210 can be improved.

[0016] [Aspect 5] As illustrated in FIG. 5, the control unit 90 may perform a process of identifying the media type of the media group G1. The target range may include a first target range (for example, F1 - ΔF1 to F1 + ΔF1) applied when the media type is the first media type, and a second target range (for example, F2 - ΔF2 to F2 + ΔF2) applied when the media type is a second media type different from the first media type. Here, the second target range is different from the first target range. When the media type is the first media type, the control unit 90 may raise and lower the placement unit 10 on the lifting unit 20 so that the detected pressing force F0 falls within the first target range (for example, F1 - ΔF1 to F1 + ΔF1). When the media type is the second media type, the control unit 90 may raise and lower the placement unit 10 on the lifting unit 20 so that the detected pressing force F0 falls within the second target range (for example, F2 - ΔF2 to F2 + ΔF2). In the above case, since the media ME1 is fed from the placement unit 10 in order from above in a state where the pressing force F0 of the pick roller 31 is within the target range suitable for the media type, the stability of feeding the media from the placement unit can be improved. As a result, the occurrence of jams can be further suppressed.

[0017] Here, in the present application, "first", "second",... are terms for identifying each component included in a plurality of components having similarities and do not mean an order. This proviso also applies to the following aspects.

[0018] [Aspect 6] As illustrated in FIG. 5, the target range may include a third target range (e.g., F3 - ΔF3 to F3 + ΔF3) applicable when the medium type is a third medium type different from the first and second medium types. Here, assume that the first medium type is plain paper, the second medium type is thin paper thinner than the plain paper, and the third medium type is thick paper thicker than the plain paper. The upper limit value (e.g., F1 + ΔF1) of the first target range may be larger than the upper limit value (e.g., F2 + ΔF2) of the second target range, and the lower limit value (e.g., F1 - ΔF1) of the first target range may be larger than the lower limit value (e.g., F2 - ΔF2) of the second target range. Also, the upper limit value (e.g., F3 + ΔF3) of the third target range may be larger than the upper limit value (e.g., F1 + ΔF1) of the first target range, and the lower limit value (e.g., F3 - ΔF3) of the third target range may be larger than the lower limit value (e.g., F1 - ΔF1) of the first target range. In the above case, since the pressing force F0 of the pick roller 31 falls within the target ranges suitable for plain paper, thin paper, and thick paper respectively, and the medium ME1 is fed from the placement unit 10 in order from above, the stability of feeding the medium from the placement unit can be improved.

[0019] [Aspect 7] As illustrated in FIG. 5, the medium feeding device 3 may further include a setting reception unit 61, 111 for receiving the setting of the medium type. The control unit 90 may raise and lower the placement unit 10 with respect to the elevating unit 20 so that the detected pressing force F0 falls within the target range (e.g., Fi - ΔFi to Fi + ΔFi) applicable to the medium type set in the setting reception unit 61, 111. In the above case, since the pressing force F0 of the pick roller 31 falls within the target range suitable for the set medium type, and the medium ME1 is fed from the placement unit 10 in order from above, the stability of feeding the medium from the placement unit can be improved.

[0020] [Aspect 8] As illustrated in FIGS. 6 to 10, the elevating unit 20 may include a motor 21 that elevates the placement unit 10 when an electric current flows. The control unit 90 may acquire a current value I0 corresponding to the current flowing through the motor 21 when the motor 21 raises the placement unit 10 in a state where the pick roller 31 is not in contact with the media group G1. The control unit 90 may identify the media type based on the current value I0. The control unit 90 may raise and lower the placement unit 10 in the elevating unit 20 so that the detected pressing force F0 falls within the target range (for example, Fi - ΔFi to Fi + ΔFi) applied to the identified media type. In the above case, since the media ME1 is fed in order from above from the placement unit 10 while the pressing force F0 of the pick roller 31 is within the target range suitable for the specified media type, the stability of feeding the media from the placement unit can be improved. In addition, since the user can be saved the trouble of setting the media type, the convenience can be improved.

[0021] [Aspect 9] As illustrated in FIG. 11, when the specified media type is different from the media type set in the setting reception units 61 and 111, the control unit 90 may output an alert to the display units 60 and 110. In the above case, since an alert can be confirmed on the display units 60 and 110 when the automatically identified media type is different from the set media type, an error in setting the media type can be easily grasped. Here, the display unit may be provided in the media feeding device or in an external device such as an external computer. This remark also applies to the following aspects.

[0022] [Aspect 10] As illustrated in FIG. 12, the medium feeding device 3 may further include a setting reception unit 61, 111 that receives a setting as to whether or not the medium group G1 is in a mixed medium type mode in which a plurality of medium types are mixed. The target range may include a fixed target range (for example, Ft - ΔFt to Ft + ΔFt) applied when the mixed medium type mode is set, and an individual target range (for example, Fi - ΔFi to Fi + ΔFi) that can vary according to the medium type when the mixed medium type mode is not set. When the mixed medium type mode is set, the control unit 90 may raise and lower the placement unit 10 with respect to the elevating unit 20 so that the detected pressing force F0 falls within the fixed target range (for example, Ft - ΔFt to Ft + ΔFt). When the mixed medium type mode is not set, the control unit 90 may raise and lower the placement unit 10 with respect to the elevating unit 20 so that the detected pressing force F0 falls within the individual target range (for example, Fi - ΔFi to Fi + ΔFi). In the above case, since the medium ME1 is fed in order from above from the placement unit 10 in a state where the pressing force F0 of the pick roller 31 falls within a target range according to whether or not it is in the mixed medium type mode, the stability of feeding the medium from the placement unit can be improved.

[0023] [Aspect 11] Incidentally, a control method for a medium feeding device 3 according to an aspect is a control method for a medium feeding device 3 including the placement unit 10, the elevating unit 20, and the pick unit 30, and includes the following steps as illustrated in FIG. 4 and the like. (a1) A detection step ST1 of detecting the pressing force F0. (a2) An elevating control step ST2 of raising and lowering the placement unit 10 with respect to the elevating unit 20 so that the detected pressing force F0 falls within a target range (for example, Ft - ΔFt to Ft + ΔFt). The above aspect can provide a control method for a medium feeding device that can improve the stability of feeding a medium from a placement unit of a medium group. As a result, the occurrence of jams can be suppressed.

[0024] Furthermore, the above-described aspects are applicable to a media conveyance device including the above-described media feeding device, an image reading device including the above-described media feeding device, a recording device including the above-described media feeding device, a media feeding system including the above-described media feeding device, a control method for the above-described media conveyance device, a control method for the above-described image reading device, a control method for the above-described recording device, a control program for the above-described media feeding device, a control program for the above-described media conveyance device, a control program for the above-described image reading device, a control program for the above-described recording device, a computer-readable non-transitory medium on which any of the above-described control programs is recorded, and the like. Any of the above-described devices may be composed of a plurality of distributed parts.

[0025] (2) Specific example of an image reading device including a media feeding device: FIG. 1 is a longitudinal sectional view schematically illustrating an image reading device 1 including a media feeding device 3. FIG. 2 schematically illustrates the media feeding device 3. FIG. 3 is a block diagram schematically illustrating the configuration of the electric circuit of the image reading device 1 together with an external device 100. The image reading device 1 includes a media feeding device 3, a media conveyance device 4, a reading unit 70, etc., and reads an image IM1 of a media ME1 as a document. The reading unit 70 shown in FIG. 1 includes a first reading unit 71 capable of reading the image IM1 on the upper surface of the media ME1 and a second reading unit 72 capable of reading the image IM1 on the lower surface of the media ME1. The media feeding device 3 includes a placement unit 10 for a media group G1, a lifting unit 20 for the placement unit 10, a pick unit 30, a detection unit 40 for the pressing force F0 from a pick roller 31 to the media group G1, a display unit 60, a setting reception unit 61, and a control unit 90. The media conveyance device 4, the reading unit 70, and the control unit 90 are provided inside a housing 8 of the image reading device 1. Note that reference sign D1 indicates the feeding direction of the media ME1, and reference sign D2 indicates the lifting direction of the placement unit 10.

[0026] The placement unit 10, also called an elevator, is capable of lifting. The media group G1 is loaded on the placement unit 10. The media group G1 means one or more media ME1, which is a media bundle in which a plurality of media ME1 are stacked. The placement unit 10 shown in FIG. 2 is provided with a media presence / absence sensor 18 capable of detecting whether or not the media group G1 is placed thereon. The elevating unit 20 shown in Fig. 2 includes a motor 21 and an elevating mechanism 22, and elevates the mounting unit 10. The motor 21 elevates the mounting unit 10 via the elevating mechanism 22 when current flows through it. As the motor 21, a servo motor provided with a servo amplifier capable of detecting a current value I0 corresponding to the current flowing through the motor 21 can be used. As the elevating mechanism 22, a mechanism using a ball screw or the like can be used.

[0027] The pick-up unit 30 shown in Fig. 2 includes a pick-up roller 31 that contacts the upper part G1a of the medium group G1, and a support portion 32 that applies a downward force to the pick-up roller 31. The pick-up roller 31, also called a pick-up roller, is rotatable in the direction of feeding the medium ME1 in the feeding direction D1 by a driving source (not shown) such as a servo motor. When feeding the medium ME1, the control unit 90 rotates the pick-up roller 31 by a predetermined amount with respect to the driving source. The support portion 32 is rotatable about a shaft 33 as a fulcrum, and includes an arm 34 that supports the rotatable pick-up roller 31, and a spring 35 that applies a force to the arm in a direction to apply a downward force to the pick-up roller 31. The pick-up unit 30 including the pick-up roller 31 and the support portion 32 feeds the medium ME1 in the feeding direction D1 in order from above while applying a downward pressing force F0 from the pick-up roller 31 to the medium group G1 according to the control from the control unit 90.

[0028] The detection unit 40 shown in FIG. 2 includes a force sensor 41 using a crystal, and the force sensor 41 detects the pressing force F0. The detection unit 40 may be a capacitance type force sensor, but the force sensor 41 using a crystal can detect the pressing force F0 with higher resolution than a capacitance type force sensor. As the detection unit 40, a force sensor for detecting a linearly directed force may be used, or a torque sensor for detecting a torque that is a moment of a rotating force may be used. As the force sensor, a six-axis force sensor having three force axes and three moment axes, a three-axis force sensor having three force axes, a one-axis force sensor having one force axis, etc. can be used. When a force sensor or a six-axis force sensor is used, the force acting on the pick roller 31 can be detected, and when a torque sensor or a six-axis force sensor is used, the moment applied to the pick roller 31 can be detected.

[0029] The medium transport device 4 transports the media ME1 one by one from the pick unit 30 via the reading unit 70 of the medium ME1 to the stacker 55. The medium transport device 4 shown in FIG. 1 includes a feed roller 51, a separation roller 52, a plurality of transport roller pairs 53, and a drive source 54. The feed roller 51 rotates in a direction to feed the medium ME1 in the feed direction D1 above the transport path P1, and the separation roller 52 rotates in a direction to return the medium ME1 in a direction opposite to the feed direction D1 below the transport path P1. When a plurality of media ME1 are sent between the feed roller 51 and the separation roller 52, the media ME1 are separated one by one and sent in the feed direction D1 by the feed roller 51. The plurality of transport roller pairs 53 are positioned along the transport path P1 including the curved inversion path P2, and transport the medium ME1 along the transport path P1. The drive source 54 rotates the feed roller 51, the separation roller 52, and the plurality of transport roller pairs 53 according to the control from the control unit 90. As described above, the medium transport device 4 transports the media ME1 one by one from the pick unit 30 to the stacker 55 via the first reading unit 71 and the second reading unit 72 along the transport path P1. Since the transport path P1 has the curved inversion path P2, the medium ME1 transported by the medium transport device 4 is inverted and loaded onto the stacker 55.

[0030] The display unit 60 displays information such as the status of the image reading device 1, the information input from the setting reception unit 61, etc. Examples of the status of the image reading device 1 include a state where image reading processing can be executed, a state where image reading is in progress, an alert state, etc. Examples of the display unit 60 include a liquid crystal display panel, a light emitting diode, a combination of these, etc. The setting reception unit 61 receives an operation for inputting information such as the media type and mode from the user. For example, the setting reception unit 61 receives a setting of the media type and receives a setting as to whether it is a media mixed mode in which a plurality of media types are mixed in the media group G1. Examples of the setting reception unit 61 include a hard key, a touch panel attached to the display unit 60, etc.

[0031] The control unit 90 shown in FIG. 3 includes a CPU (Central Processing Unit) 91 which is a processor, a ROM (Read Only Memory) 92, a RAM (Random Access Memory) 93, a storage unit 94, an I / F (interface) 95, etc. The aforementioned elements (91 to 95) are electrically connected and can input and output information to each other. Note that the ROM 92 and the RAM 93 are semiconductor memories. Examples of the storage unit 94 include non-volatile semiconductor memories such as flash memories, magnetic storage devices such as hard disks, etc. The control unit 90 can acquire input information from the setting reception unit 61, can acquire information indicating the presence or absence of the media group G1 from the media presence / absence sensor 18, can acquire the pressing force F0 from the detection unit 40, and can acquire the reading data of the image IM1 of the media ME1 from the reading unit 70. The control unit 90 can display various information including alerts on the display unit 60, controls the elevating unit 20 that raises and lowers the placement unit 10, controls the pick-up unit 30 that rotates the pick-up roller 31, and controls the media conveyance device 4 for image reading processing. Further, the control unit 90 may include a plurality of CPUs, or may include an ASIC (Application Specific Integrated Circuit) instead of or together with the CPU. Accordingly, the processing performed by the control unit 90 may be divided among a plurality of CPUs, or may be performed by the ASIC instead of or together with the CPU.

[0032] The external device 100 includes a display unit 110, a setting reception unit 111, etc., and is connected to the image reading device 1. Examples of the external device 100 include personal computers, tablet terminals, mobile phones such as smartphones, etc.

[0033] Here, the medium feeding device 903 of the comparative example shown in FIG. 15 will be described. Among the elements of the medium feeding device 903 shown in FIG. 15, elements similar to those of the medium feeding device 3 shown in FIG. 2 are denoted by the same reference numerals as those shown in FIG. 2, and detailed description thereof will be omitted. The medium feeding device 903 includes a placement unit 10 for the medium group G1, a lifting unit 20 for the placement unit 10, a pick unit 30, a control unit (not shown), etc., but does not include a detection unit 40 for the pressing force F0. The pick roller 31 feeds the media ME1 one by one from the medium group G1 in the feeding direction D1. Each time the medium ME1 is fed out, the pick roller 31 descends around the center, so that the pick roller 31 can contact the next medium ME1. By repeating driving and stopping at appropriate timings, the pick roller 31 can successively pass the media ME1 to the feeding roller 51 and the separating roller 52. When the feeding of the medium ME1 is repeated, the pick roller 31 descends too much and cannot feed out the medium ME1. Therefore, the lifting unit 20 raises the placement unit 10 by a predetermined amount triggered by the sensor dog 931 of the pick unit 30 blocking the sensor optical axis 932. Alternatively, the lifting unit 20 raises the placement unit 10 by a certain amount each time one medium ME1 is fed out.

[0034] In any case, the posture of the pick unit 30 cannot be maintained at an optimal angle when the medium ME1 is sent out. For this reason, as shown by the dashed-dotted line in Fig. 15, the medium ME1 sent out fluctuates up and down, or the pressing force from the pick roller 31 to the medium group G1 fluctuates, which leads to the occurrence of jams.

[0035] In this specific example, the detection unit 40 detects the downward pressing force F0 applied from the pick roller 31 to the medium group G1, and the control unit 90 moves the mounting part 10 up and down on the lifting part 20 so that the detected pressing force F0 falls within the target range. Thereby, the stability of feeding the medium ME1 from the mounting part 10 of the medium group G1 is improved, and the occurrence of jams is suppressed. For example, by using a force sensor for detecting the pressing force F0, even if the medium group G1 during continuous feeding gradually decreases, the control unit 90 can detect and feedback the moment around the fulcrum of the pick unit 30 with the force sensor and perform control. By controlling the lifting of the mounting part 10 so that the moment generated around the fulcrum of the pick unit 30 is always substantially constant, the angle of the pick unit 30 and the pressing force F0 received by the pick roller 31 from the medium group G1 can be always maintained substantially constant. As the force sensor, various sensors described above can be used. There is a force sensor for detecting six senses (Fx, Fy, Fz, Mx, My, Mz) for robots, but if one of the six senses can be detected, the pressing force F0 can be maintained substantially constant.

[0036] (3) Specific example of the process performed by the image reading device including the medium feeding device: FIG. 4 schematically illustrates the feeding process performed by the control unit 90. In the initial state, it is assumed that the placement unit 10 is in a lower position such that the pick roller 31 does not contact the media group G1. The feeding process starts when the control unit 90 receives an instruction to start feeding the medium ME1. The feeding start instruction may be an instruction resulting from a pressing operation on the scan start button included in the setting reception unit 61 of the image reading device 1, or may be an instruction such as a predetermined scan start operation on the setting reception unit 111 of the external device 100. When the control unit 90 receives a feeding start instruction resulting from a pressing operation on the scan start button from the setting reception unit 61 or a feeding start instruction resulting from a scan start operation from the setting reception unit 111, it starts the feeding process. Here, steps S108 and S114 correspond to the detection step ST1, and steps S110 to S112 and S116 correspond to the lifting control step ST2. Hereinafter, the description of "step" may be omitted, and the step number may be indicated in parentheses.

[0037] When the feeding process starts, the control unit 90 performs a predetermined feeding preparation process such as acquiring information from the medium presence / absence sensor 18 (S102), and determines whether or not the medium group G1 is placed on the placement unit 10 based on the information from the medium presence / absence sensor 18 (S104). If the information from the medium presence / absence sensor 18 indicates that there is no medium group G1, that is, if the medium group G1 is not placed on the placement unit 10, the control unit 90 ends the feeding process. If the information from the medium presence / absence sensor 18 indicates that there is a medium group G1, that is, if the medium group G1 is placed on the placement unit 10, the control unit 90 sets a target pressing force Ft or Fi, which is the target pressing force F0 for stopping the lifting of the placement unit 10. Here, the target pressing force Ft is a fixed pressing force regardless of the medium type, and the target pressing force Fi is a pressing force that can vary depending on the medium type.

[0038] After setting the target pressing force, the control unit 90 causes the detection unit 40 to detect the pressing force F0 and acquires the pressing force F0 from the detection unit 40 (S108). Next, the control unit 90 determines the amount of rise of the placement unit 10 according to the setting (S110). For example, the image reading apparatus 1 may store in the storage unit 94 the amount of rise of the placement unit corresponding to the setting of the target pressing force Ft or Fi. In this case, the control unit 90 may acquire from the storage unit 94 the amount of rise of the placement unit corresponding to the setting of the target pressing force Ft or Fi. Thereafter, the control unit 90 raises the placement unit 10 by the determined amount of rise in the elevating unit 20 (S112). After that, the control unit 90 causes the detection unit 40 to detect the pressing force F0 and acquires the pressing force F0 from the detection unit 40 (S114). Next, the control unit 90 determines whether the pressing force F0 is within the target range (S116).

[0039] The target range of the pressing force F0 is set to a range including the target pressing force Ft or Fi. For example, a fixed target range regardless of the type of medium can be set as Ft - ΔFt to Ft + ΔFt considering the difference in the allowable amount ΔFt (ΔFt > 0) centered on the target pressing force Ft (Ft > 0). In this case, if the detected pressing force F0 is equal to or greater than Ft - ΔFt and equal to or less than Ft + ΔFt, it is determined that the pressing force F0 is within the target range.

[0040] If the pressing force F0 is not within the target range in S116, the control unit 90 repeats the processes of S110 to S116. If the pressing force F0 is within the target range in S116, the control unit 90 controls the pick unit 30 so as to feed one sheet of the medium ME1 from the medium group G1 in the feeding direction D1 by the rotation of the pick roller 31 (S118), and returns the process to S102.

[0041] As described above, when the control unit 90 receives an instruction to start feeding the medium ME1, it raises the placement unit 10 of the elevating unit 20, and when the pressing force F0 detected by the detection unit 40 falls within the target range (for example, Ft - ΔFt to Ft + ΔFt), it rotates the pick roller 31 so that the medium ME1 is fed in the feeding direction D1. In other words, the control unit 90 raises and lowers the placement unit 10 of the elevating unit 20 so that the detected pressing force F0 falls within the target range (for example, Ft - ΔFt to Ft + ΔFt). The pick unit 30 feeds the medium ME1 in the feeding direction D1 in order from above while applying the pressing force F0 within the target range from the pick roller 31 to the medium group G1. As a result, the medium ME1 is fed in order from above from the placement unit 10 while the pressing force F0 of the pick roller 31 remains within the target range. Therefore, in this specific example, the stability of feeding the medium ME1 from the placement unit 10 of the medium group G1 can be improved, the occurrence of jams can be suppressed, and the occurrence of waste paper can be suppressed.

[0042] Incidentally, the control unit 90 may perform the medium type setting process illustrated in FIG. 5. In this case, the control unit 90 may set a target pressing force Fi according to the set medium type. FIG. 5 also shows a medium type setting screen 500 displayed on the display units 60 and 110, and a target pressing force table TA1 stored in the storage unit 94 or the external device 100. The medium type setting process starts, for example, when the setting reception unit 61 of the image reading apparatus 1 receives a predetermined operation for setting the medium type to be fed. Also, the medium type setting process starts when the control unit 90 receives a medium type setting request from the external device 100 due to the setting reception unit 111 receiving a predetermined operation for setting the medium type to be fed.

[0043] When the media type setting process starts, the control unit 90 causes the media type setting screen 500 to be displayed on at least one of the display units 60 and 110, and accepts the setting of the media type by the setting reception unit 61 or 111 (S152). The media type setting screen 500 has selection areas for media types such as plain paper, thin paper, thick paper, and photo paper. The setting reception unit 61 or 111 accepts a selection operation of any one media type from among the plurality of selection areas from the user. Therefore, the control unit 90 can acquire information indicating the media type corresponding to the operated selection area from the setting reception unit 61 or the external device 100. The media type setting process of S152 can be said to be a process for specifying the media types of the media group G1.

[0044] Thereafter, the control unit 90 sets the target pressing force Fi associated with the set media type according to the target pressing force table TA1 (S154). In the target pressing force table TA1, the target pressing force F1 for plain paper as the first media type, the target pressing force F2 for thin paper as the second media type, the target pressing force F3 for thick paper as the third media type, the target pressing force F4 for photo paper as the fourth media type, etc. are stored. The target pressing forces F1 to F4 are set such that, for example, 0 < F2 < F1 < F3 < F4. Here, let the allowable amounts centered on the target pressing forces F1, F2, F3, and F4 be ΔF1, ΔF2, ΔF3, and ΔF4, respectively. The first target range applied when the media type is plain paper can be F1 - ΔF1 to F1 + ΔF1. The second target range applied when the media type is thin paper can be F2 - ΔF2 to F2 + ΔF2. Note that the lower limit value (F2 - ΔF2) of the second target range is smaller than the lower limit value (F1 - ΔF1) of the first target range, and the upper limit value (F2 + ΔF2) of the second target range is smaller than the upper limit value (F1 + ΔF1) of the first target range. The third target range applied when the media type is thick paper can be F3 - ΔF3 to F3 + ΔF3. Note that the lower limit value (F3 - ΔF3) of the third target range is larger than the lower limit value (F1 - ΔF1) of the first target range, and the upper limit value (F3 + ΔF3) of the third target range is larger than the upper limit value (F1 + ΔF1) of the first target range. The fourth target range applied when the media type is photo paper can be F4 - ΔF4 to F4 + ΔF4.

[0045] When the media type setting process ends, the control unit 90 sets a target pressing force Fi corresponding to the set media type in the target pressing force setting process of S106 shown in FIG. 4. In the example shown in FIG. 5, when plain paper is set, the target pressing force F1 is set; when thin paper is set, the target pressing force F2 is set; when thick paper is set, the target pressing force F3 is set; and when photo paper is set, the target pressing force F4 is set. In the determination process of S116 shown in FIG. 4, when the pressing force F0 is equal to or greater than (Fi - ΔFi) and equal to or less than (Fi + ΔFi), the control unit 90 determines that the pressing force F0 is within the target range and performs the media feeding process of S118.

[0046] As described above, when the media type is plain paper, the control unit 90 raises and lowers the mounting portion 10 on the elevating portion 20 so that the detected pressing force F0 falls within the first target range (F1 - ΔF1 to F1 + ΔF1). When the media type is thin paper, the control unit 90 raises and lowers the mounting portion 10 on the elevating portion 20 so that the detected pressing force F0 falls within the second target range (F2 - ΔF2 to F2 + ΔF2). When the media type is thick paper, the control unit 90 raises and lowers the mounting portion 10 on the elevating portion 20 so that the detected pressing force F0 falls within the third target range (F3 - ΔF3 to F3 + ΔF3). When the media type is photo paper, the control unit 90 raises and lowers the mounting portion 10 on the elevating portion 20 so that the detected pressing force F0 falls within the fourth target range (F4 - ΔF4 to F4 + ΔF4). As described above, the medium ME1 is sequentially fed from above the mounting portion 10 in a state where the pressing force F0 of the pick roller 31 falls within the target range suitable for the set media type. Therefore, in this specific example, the stability of feeding the medium ME1 from the mounting portion 10 of the medium group G1 can be further improved, and the occurrence of jams can be further suppressed.

[0047] When a mechanism for physically switching the posture of the pick unit is provided in the media feeder to set a separation mode specialized for a specific media type, the number of separable modes that can be mounted is limited to two or three types. By controlling the lifting and lowering of the placement unit 10 based on the pressing force F0 detected by the detection unit 40, the need for a physical posture switching mechanism is eliminated, and the required separation force can be set according to the number of sheets of paper. As a result, when the user specifies the media type before reading a group of documents, the target pressing force Fi corresponding to the media type is automatically set, eliminating the need to manually switch the posture of the pick unit. The elimination of the mechanism for switching the posture of the pick unit reduces the number of parts and can also lead to cost reduction.

[0048] Also, as illustrated in FIGS. 6 to 9, the control unit 90 may identify the media type based on the current value I0 of the motor 21 and set the target pressing force Fi corresponding to the identified media type. FIG. 6 schematically illustrates the media feeder 3 when the motor 21 raises the placement unit 10. FIG. 6 shows the media feeder 3 in a state where the placement unit 10 is at its lowest position. FIG. 7 schematically illustrates the correspondence CO1 between the current value I (A) corresponding to the current flowing through the motor 21 and the weight W (g) of the media group G1 placed on the placement unit 10. In FIG. 7, the horizontal axis represents the current value I, and the vertical axis represents the weight W. FIG. 8 schematically illustrates the structure of the unit sheet weight table TA2 stored in the storage unit 94 or the external device 100. FIG. 9 schematically illustrates a feeding process for automatically determining the media type when the number N of the media ME1 included in the media group G1 is known.

[0049] When the motor 21 raises the mounting portion 10 at a constant speed V with the pick roller 31 not in contact with the media group G1 as shown in FIG. 6, the larger the combined weight of the mounting portion 10 and the media group G1, the larger the current flowing through the motor 21. From this, as shown in FIG. 7, the correspondence CO1 between the weight W of the media group G1 and the current value I of the motor 21 is such that the weight W increases as the current value I increases. Therefore, in order to obtain the weight W of the media group G1 placed on the mounting portion 10, the correspondence CO1 may be obtained in advance. If the current value I of the motor 21 is known, the weight W of the media group G1 placed on the mounting portion 10 can be obtained according to the correspondence CO1. Also, the weight W of the media group G1 is proportional to the number N of the media ME1. When the media group G1 includes N sheets of the media ME1, the weight ΔW per sheet of the media is W / N. In the unit weight per sheet table TA2 shown in FIG. 8, as the weight ΔW per sheet of the media, the weight ΔW1 of plain paper, the weight ΔW2 of thin paper, the weight ΔW3 of thick paper, the weight ΔW4 of photographic paper, etc. are stored. These weights ΔW can be determined by actually measuring the weight of the media ME1.

[0050] The control unit 90 performs the feeding process according to the flowchart shown in FIG. 9. In the initial state, it is assumed that the mounting portion 10 is in a lower position where the pick roller 31 is not in contact with the media group G1. The feeding process shown in FIG. 9 starts when the control unit 90 receives an instruction to start feeding the media ME1 after setting the number N of the media group G1. The setting of the number N may be by operating the number N on the setting reception unit 61 of the image reading device 1 or by operating the number N on the setting reception unit 111 of the external device 100. The control unit 90 acquires the number N from the setting reception unit 61 or the external device 100 and starts the feeding process when it receives the feeding start instruction. Here, S212 and S218 correspond to the detection step ST1, and S214 to S216 and S220 correspond to the lifting control step ST2.

[0051] When the feeding process starts, the control unit 90 performs the same feeding preparation process as S102 shown in FIG. 4 (S202), and determines whether the media group G1 is placed on the placement unit 10 in the same manner as S104 shown in FIG. 4 (S204). When the media group G1 is placed on the placement unit 10, the control unit 90 raises the placement unit 10 on the lifting unit 20 in a state where the pick roller 31 is not in contact with the media group G1, and acquires the current value I0 of the motor 21 from the lifting unit 20 (S206). The lifting unit 20 detects the current value I0 corresponding to the current flowing through the motor 21 when the motor 21 raises the placement unit 10. Therefore, the control unit 90 can acquire the current value I0 from the lifting unit 20. Next, the control unit 90 identifies the media type based on the current value I0 (S208). The control unit 90 can obtain the weight W of the media group G1 placed on the placement unit 10 from the current value I0 according to the correspondence relationship CO1 in FIG. 7, and can calculate the weight per sheet of the media ΔW = W / N. Moreover, the control unit 90 only needs to identify the media type associated with the weight closest to the calculated weight ΔW = W / N among the weights per sheet of the media ΔW1 to ΔW4 stored in the unit number weight table TA2 shown in FIG. 8.

[0052] Next, the control unit 90 sets the target pressing force Fi according to the identified media type (S210). In the example shown in FIG. 5, when plain paper is set, the target pressing force F1 is set, when thin paper is set, the target pressing force F2 is set, when thick paper is set, the target pressing force F3 is set, and when photo paper is set, the target pressing force F4 is set. Next, the control unit 90 causes the detection unit 40 to detect the pressing force F0, acquires the pressing force F0 from the detection unit 40 (S212), determines the lifting amount of the placement unit 10 according to the setting (S214), and raises the placement unit 10 on the lifting unit 20 by the determined lifting amount (S216). Moreover, the control unit 90 causes the detection unit 40 to detect the pressing force F0, acquires the pressing force F0 from the detection unit 40 (S218), and determines whether the pressing force F0 is within the target range (S220).

[0053] The target range of the pressing force F0 is set to a range including the target pressing force Fi. The individual target range that can vary according to the medium type can be set as Fi - ΔFi to Fi + ΔFi considering the difference in the allowable amount ΔFi (ΔFi > 0) centered around the target pressing force Fi (Fi > 0). In this case, if the detected pressing force F0 is equal to or greater than Fi - ΔFi and equal to or less than Fi + ΔFi, it is determined that the pressing force F0 is within the target range. If the pressing force F0 is not within the target range in S220, the control unit 90 repeats the processes of S214 to S220. If the pressing force F0 is within the target range in S220, the control unit 90 controls the pick unit 30 to feed the medium ME1 from the medium group G1 by one sheet in the feeding direction D1 by the rotation of the pick roller 31 (S222), and returns the process to S202.

[0054] As described above, when the pressing force F0 detected by the detection unit 40 falls within the target range (Fi - ΔFi to Fi + ΔFi), the control unit 90 rotates the pick roller 31 so that the medium ME1 is fed in the feeding direction D1. In other words, the control unit 90 raises and lowers the mounting unit 10 on the elevating unit 20 so that the detected pressing force F0 falls within the target range (Fi - ΔFi to Fi + ΔFi). The pick unit 30 feeds the medium ME1 in the feeding direction D1 in order from above while applying the pressing force F0 within the target range from the pick roller 31 to the medium group G1. As a result, the medium ME1 is fed in order from above from the mounting unit 10 while the pressing force F0 of the pick roller 31 is within the target range suitable for the specified medium type. Therefore, in this specific example, the stability of feeding the medium ME1 from the mounting unit 10 of the medium group G1 can be further improved, and the occurrence of jams can be further suppressed.

[0055] Furthermore, as illustrated in FIG. 10, even if the number N of the media ME1 included in the media group G1 is unknown, the control unit 90 can specify the medium type based on the current value I0 of the motor 21. FIG. 10 schematically illustrates the structure of the unit height weight table TA3 stored in the storage unit 94 or the external device 100. Hereinafter, the description will be made with reference to FIGS. 6, 7, 9, etc. As shown in FIG. 6, let the height of the media group G1 be H, the maximum lifting amount H1 be the height from the lowest placement part 10 to the pick roller 31, and the actual lifting amount H2 be the height from the upper part G1a of the media group G1 placed on the lowest placement part 10 to the pick roller 31. The height H of the media group G1 is H1 - H2. The actual lifting amount H2 is obtained by calculating the difference between the position of the lowest placement part 10 in the lifting direction D2 and the position of the placement part 10 in the lifting direction D2 when the detection unit 40 detects that the media group G1 has come into contact with the pick roller 31 due to the lifting of the placement part 10. As described above, if the current value I of the motor 21 is known, the weight W of the media group G1 placed on the placement part 10 is obtained according to the correspondence relationship CO1 in FIG. 7. Here, let the weight per unit height of the media group G1 be ΔW. The weight per unit height ΔW is W / H.

[0056] In the unit height weight table TA3 shown in FIG. 10, as the weight per unit height ΔW, the weight ΔW1 of plain paper, the weight ΔW2 of thin paper, the weight ΔW3 of thick paper, the weight ΔW4 of photographic paper, etc. are stored. These weights ΔW can be determined by actually measuring the height and weight of the media group G1. Next, referring to FIG. 9, the feeding process performed by the control unit 90 will be described. In the initial state, it is assumed that the placement part 10 is in a lower position such that the pick roller 31 does not contact the media group G1. However, the number N of the media group G1 is not set, and the control unit 90 starts the feeding process triggered by receiving a feeding start instruction.

[0057] When the feeding process starts, the control unit 90 performs a feeding preparation process (S202) and determines whether the media group G1 is placed on the placement part 10 (S204). If the media group G1 is placed on the placement part 10, the control unit 90 raises the placement part 10 on the lifting part 20 in a state where the pick roller 31 does not contact the media group G1, and acquires the current value I0 of the motor 21 from the lifting part 20 (S206). Next, the control unit 90 raises the placement unit 10 on the lifting unit 20 until the media group G1 contacts the pick roller 31, obtains the actual lifting amount H2 from the lifting unit 20, calculates the height H = H1 - H2 of the media group G1, and identifies the media type based on the current value I0 (S208). The control unit 90 can obtain the weight W of the media group G1 placed on the placement unit 10 from the current value I0 according to the correspondence CO1 in FIG. 7, and can calculate the weight per unit height ΔW = W / H of the media group G1. Moreover, the control unit 90 only needs to identify the media type associated with the weight closest to the calculated weight ΔW = W / H among the weights per unit height ΔW1 to ΔW4 stored in the unit height weight table TA3 shown in FIG. 10.

[0058] Next, the control unit 90 sets a target pressing force Fi according to the identified media type (S210). Next, the control unit 90 causes the detection unit 40 to detect the pressing force F0, obtains the pressing force F0 from the detection unit 40 (S212), determines the lifting amount of the placement unit 10 according to the setting (S214), and raises the placement unit 10 on the lifting unit 20 by the determined lifting amount (S216). Moreover, the control unit 90 causes the detection unit 40 to detect the pressing force F0, obtains the pressing force F0 from the detection unit 40 (S218), and determines whether the pressing force F0 is within the target range (S220). If the pressing force F0 is not within the target range in S220, the control unit 90 repeats the processes of S214 to S220. If the pressing force F0 is within the target range in S220, the control unit 90 controls the pick unit 30 so as to feed one sheet of the media ME1 from the media group G1 in the feeding direction D1 by the rotation of the pick roller 31 (S222), and returns the process to S202.

[0059] As described above, the control unit 90 raises and lowers the mounting unit 10 on the lifting unit 20 so that the detected pressing force F0 falls within the target range (Fi - ΔFi to Fi + ΔFi). The pick unit 30 feeds the media ME1 in the feeding direction D1 in order from above while applying the pressing force F0 within the target range from the pick roller 31 to the media group G1. As a result, the media ME1 is fed from the mounting unit 10 in order from above while the pressing force F0 of the pick roller 31 falls within the target range suitable for the specified media type. Therefore, in this specific example, the stability of feeding the media ME1 from the mounting unit 10 of the media group G1 can be further improved, and the occurrence of jams can be further suppressed.

[0060] Furthermore, as illustrated in FIG. 11, when the specified media type is different from the media type set in the setting reception units 61 and 111, the control unit 90 may output an alert to the display units 60 and 110. FIG. 11 schematically illustrates a feeding process for automatically determining the media type after the media type is set. The feeding process shown in FIG. 11 has S252 and S254 added between S208 and S210 compared to the feeding process shown in FIG. 9. The feeding process shown in FIG. 11 starts when the control unit 90 receives an instruction to start feeding the media ME1 after the media type setting process shown in FIG. 5 is performed.

[0061] When the media type is specified by the processes of S202 to S208, the control unit 90 determines whether or not the specified media type matches the media type set in the setting reception unit 61 or 111 (S252). When the specified media type matches the set media type, the control unit 90 performs the processes after S210. When the specified media type is different from the set media type, the control unit 90 outputs an alert to at least one of the display units 60 and 110 (S254). Examples of the alert include character information such as "The detected paper type is different from the setting.", lighting of the display unit such as red lighting of a light-emitting diode, blinking of the display unit such as blinking of a light-emitting diode, and the like. For example, when the set media type is plain paper and the specified media type is thin paper, the alert may be more specific information such as "Thin paper has been detected. It is different from the set plain paper."

[0062] As described above, in the example shown in FIG. 11, when the automatically identified media type and the set media type are different, an alert can be confirmed on the display units 60 and 110. Therefore, the user can easily grasp an error in the setting of the media type, and can suppress the occurrence of waste paper due to the occurrence of an unintended jam.

[0063] Furthermore, the control unit 90 may perform the media type mode setting process illustrated in FIG. 12. FIG. 12 also shows a media type mode setting screen 550 displayed on the display units 60 and 110, and a target pressing force table TA1 stored in the storage unit 94 or the external device 100. The media type mode setting process starts, for example, when the setting reception unit 61 of the image reading apparatus 1 receives a predetermined operation for setting the media type mode of the media group G1. Also, the media type mode setting process starts when the control unit 90 receives a setting request for the media type mode from the external device 100 due to the setting reception unit 111 receiving a predetermined operation for setting the media type mode of the media group G1.

[0064] When the media type mode setting process starts, the control unit 90 causes at least one of the display units 60 and 110 to display the media type mode setting screen 550, and receives the setting of the media type mode by the setting reception unit 61 or 111 (S302). The media type mode setting screen 550 has a selection area for "paper type mixed mode" indicating the media type mixed mode, and a selection area for "specific paper type mode" indicating the specific media type mode. The setting reception unit 61 or 111 receives a selection operation of one of these selection areas from the user. It can be said that the setting reception unit 61 or 111 receives a setting as to whether it is a media type mixed mode in which a plurality of media types are mixed in the media group G1. The control unit 90 can acquire information indicating the media type mode corresponding to the operated selection area from the setting reception unit 61 or the external device 100.

[0065] Thereafter, the control unit 90 determines whether or not the set media type mode is the media type mixed mode (S304). When the set media type mode is the media type mixed mode, the type of each medium ME1 to be fed is not specified. Therefore, the control unit 90 sets the target pressing force to a fixed target pressing force Ft that does not depend on the medium type (S306). When the set media type mode is the specific media type mode, the control unit 90 identifies the media type of the medium group G1 as shown in FIGS. 5, 9, etc., and sets an individual target pressing force Fi corresponding to the media type according to the target pressing force table TA1 (S308).

[0066] When the media type setting process ends, the control unit 90 sets a target pressing force Fi corresponding to the set media type mode in the target pressing force setting process of S106 shown in FIG. 4. When the media type mixed mode is set, the fixed target pressing force Ft is set, and when the specific media type mode is set, the individual target pressing force Fi is set. When the media type mixed mode is set, the control unit 90 determines whether or not the pressing force F0 is within the fixed target range (Ft - ΔFt to Ft + ΔFt) in S116 shown in FIG. 4. As a result, when the media type mixed mode is set, the control unit 90 raises and lowers the mounting portion 10 on the elevating portion 20 so that the detected pressing force F0 falls within the fixed target range (Ft - ΔFt to Ft + ΔFt). When the specific media type mode is set, the control unit 90 determines whether or not the pressing force F0 is within the individual target range (Fi - ΔFi to Fi + ΔFi) in S116 shown in FIG. 4. As a result, when the media type mixed mode is not set, the control unit 90 raises and lowers the mounting portion 10 on the elevating portion 20 so that the detected pressing force F0 falls within the individual target range (Fi - ΔFi to Fi + ΔFi).

[0067] As described above, the medium ME1 is fed from the mounting portion 10 in order from above in a state where the pressing force F0 of the pick roller 31 is within the target range according to whether or not it is in the media type mixed mode. Therefore, the example shown in FIG. 12 can improve the stability of feeding the medium ME1 from the mounting portion 10 according to whether or not a plurality of media types are mixed in the medium group G1, and can suppress the occurrence of jams.

[0068] (4) Modification example: The present invention has various modifications. For example, the support portion 32 of the pick unit 30 is not limited to the rotation type by the shaft 33 and the arm 34, and may be a slide type by a slider movable in the vertical direction. Also, as illustrated in FIG. 13, the medium feeding device 3 may be provided in the recording device 2. FIG. 13 schematically illustrates the recording device 2 including the medium feeding device 3. Among the elements of the recording device 2 shown in FIG. 13, for the elements similar to the elements of the medium feeding device 3 shown in FIG. 2, the same reference numerals as those shown in FIG. 2 are given and detailed description thereof is omitted. The recording device 2 includes a medium feeding device 3, a medium conveyance device (not shown), a recording unit 80, etc., and performs recording on a medium ME1 to be recorded. Examples of the recording device 2 include an inkjet printer, an electrophotographic printer, etc. The recording device 2 may be a single printer, or may be a copier, a facsimile machine, a multifunction machine having a plurality of functions including a printing function, etc. The recording unit 80 performs recording on the medium ME1, such as printing on the medium ME1. The medium feeding device 3 includes a placement portion 10 for a medium group G1, a lifting portion 20 of the placement portion 10, a pick unit 30, a detection portion 40 for the pressing force F0 from the pick roller 31 to the medium group G1, a display portion 60, a setting reception portion 61, a control portion 90, a medium storage portion 210, a mounting portion 220, and a mounting detection portion 230. The medium conveyance device 4 conveys the medium ME1 one by one from the pick unit 30 via the recording unit 80 to the stacker. The control portion 90 can execute the processes shown in FIGS. 4, 5, 9, 11, and 12.

[0069] The recording device 2 shown in FIG. 13 includes a detachable medium storage portion 210 as a cassette. Inside the medium storage portion 210, a liftable placement portion 10 is arranged. The mounting portion 220 can mount the medium storage portion 210 at the use position. The use position means the position of the medium storage portion 210 when it is inserted to the deepest part of the mounting portion 220. The mounting detection portion 230 detects whether or not the medium storage portion 210 is mounted on the mounting portion 220.

[0070] The control unit 90 performs automatic feeding processing according to the flowchart shown in FIG. 14. In the initial state, it is assumed that the medium storage unit 210 is pulled out from the mounting unit 220, and the placement unit 10 is in a lower position such that the pick roller 31 does not contact the medium group G1. The automatic feeding processing starts when the control unit 90 receives an instruction to start feeding the medium ME1. When the automatic feeding processing starts, the control unit 90 determines whether the mounting detection unit 230 has detected that the medium storage unit 210 is mounted on the mounting unit 220 (S402). The process of S402 is repeated until the medium storage unit 210 is mounted on the mounting unit 220. When the medium storage unit 210 is mounted on the mounting unit 220, the control unit 90 determines whether the medium group G1 is placed on the placement unit 10 (S404). If the medium group G1 is not placed on the placement unit 10, the control unit 90 outputs an alert to at least one of the display units 60 and 110 (S406). Examples of the alert include character information such as "There is no paper set in the cassette.", lighting of the display unit such as red lighting of a light-emitting diode, blinking of the display unit such as blinking of a light-emitting diode, and the like.

[0071] If the medium group G1 is placed on the placement unit 10, the control unit 90 raises the placement unit 10 by the elevating unit 20 (S408), causes the detection unit 40 to detect the pressing force F0, and acquires the pressing force F0 from the detection unit 40 (S410). Next, the control unit 90 determines whether the pressing force F0 is within the target range (S412). If the pressing force F0 is not within the target range, the control unit 90 repeats the processes of S408 to S412. If the pressing force F0 is within the target range, the control unit 90 controls the pick unit 30 to feed one sheet of the medium ME1 from the medium group G1 in the feeding direction D1 by the rotation of the pick roller 31 (S414), and returns the process to S408 until the recording is completed.

[0072] As described above, when the mounting detection unit 230 detects the mounting of the medium storage unit 210, the control unit 90 raises the mounting unit 10 on the lifting unit 20 so that the pressing force F0 detected by the detection unit 40 falls within the target range. The pick unit 30 feeds the media ME1 in the feeding direction D1 in order from the top while applying the pressing force F0 within the target range from the pick roller 31 to the media group G1. As a result, the media ME1 is fed in order from the top from the mounting unit 10 while the pressing force F0 of the pick roller 31 remains within the target range. Since the pressing force F0 of the pick roller 31 falls within the target range when the medium storage unit 210 is mounted on the mounting unit 220, the examples shown in FIGS. 13 and 14 can improve the stability of feeding the media ME1 from the mounting unit 10 after the mounting of the medium storage unit 210, and can suppress the occurrence of jams.

[0073] (5) Conclusion: As described above, according to the present invention, it is possible to provide a configuration or the like that can improve the stability of feeding a medium from a mounting portion of a medium group in various modes. Of course, the above-described basic operations and effects can also be obtained in an aspect consisting only of the constituent elements according to the independent claims. In addition, a configuration in which each configuration disclosed in the above-described examples is mutually replaced or the combination is changed, a known technique, and a configuration in which each configuration disclosed in the above-described examples is mutually replaced or the combination is changed, etc. are also feasible. The present invention includes these configurations and the like.

Description of Reference Numerals

[0074] 1…Image reading device, 2…Recording device, 3…Media feeding device, 4…Media conveying device, 10…Placement unit, 18…Media presence sensor, 20…Lifting unit, 21…Motor, 22…Lifting mechanism, 30…Pickup unit, 31…Pickup roller, 32…Support unit, 40…Detection unit, 41…Force sensor, 51…Feeding roller, 52…Separation roller, 60…Display unit, 61…Setting reception unit, 70…Reading unit, 80…Recording unit, 90…Control unit, 100…External device, 110…Display unit, 111…Setting reception unit, 210…Media storage unit, 220…Mounting unit, 230…Mounting detection unit, 500…Media type setting screen, 550…Media type mode setting screen, CO1…Corresponding relationship, D1…Feeding direction, D2…Lifting direction, F0…Pressing force, F1~F4, Fi, Ft…Target pressing force, G1…Media group, G1a…Upper part, H…Height, H1…Maximum rising amount, H2…Actual rising amount, I0…Current value, IM1…Image, ME1…Media, ST1…Detection process, ST2…Lifting control process, TA1…Target pressing force table, TA2…Weight per unit number table, TA3…Weight per unit height table, ΔW, ΔW1~ΔW4…Weight.

Claims

1. A placement part on which a group of media is placed, A lifting part that raises and lowers the placement part, A pick roller that contacts the upper part of the media group, and a support part that applies a downward force to the pick roller, including a pick unit that feeds the media in the feeding direction in order from above while applying a downward pressing force from the pick roller to the media group, A control unit, A detection unit that detects the pressing force, The control unit raises and lowers the placement part by the lifting part so that the detected pressing force falls within a target range, a media feeding device.

2. The detection unit includes a force sensor using a crystal, and the force sensor detects the pressing force, the media feeding device according to claim 1.

3. The control unit can receive an instruction to start feeding the media. When receiving the feeding start instruction, it raises the placement part by the lifting part and rotates the pick roller so that the media is fed in the feeding direction when the pressing force detected by the detection unit enters the target range, the media feeding device according to claim 1.

4. A media storage part in which the placement part is arranged inside, A mounting part to which the media storage part can be mounted at the use position, A mounting detection unit that detects whether the media storage part is mounted on the mounting part, When the control unit detects the mounting of the media storage part by the mounting detection unit, it raises the placement part by the lifting part so that the pressing force detected by the detection unit falls within the target range, the media feeding device according to claim 1.

5. The control unit performs a process of specifying the media type of the media group, The target range includes a first target range applied when the media type is a first media type, and a second target range applied when the media type is a second media type different from the first media type, The second target range is different from the first target range, The control unit, When the media type is the first media type, it raises and lowers the placement part by the lifting part so that the detected pressing force falls within the first target range, When the media type is the second media type, it raises and lowers the placement part by the lifting part so that the detected pressing force falls within the second target range, the media feeding device according to any one of claims 1 to 4.

6. The target range includes a third target range applied when the media type is a third media type different from the first media type and the second media type, The first medium type is plain paper, the second medium type is thin paper thinner than the plain paper, and the third medium type is thick paper thicker than the plain paper. The upper limit value of the first target range is larger than the upper limit value of the second target range, the lower limit value of the first target range is larger than the lower limit value of the second target range, the upper limit value of the third target range is larger than the upper limit value of the first target range, and the lower limit value of the third target range is larger than the lower limit value of the first target range. The media feeding device according to claim 5.

7. Further comprising a setting reception unit that receives the setting of the medium type. The control unit raises and lowers the placement unit on the lifting unit so that the detected pressing force falls within the target range applied to the medium type set in the setting reception unit. The media feeding device according to claim 5.

8. The lifting unit includes a motor that raises and lowers the placement unit by flowing an electric current. The control unit acquires a current value corresponding to the current flowing through the motor when the motor raises the placement unit in a state where the pick roller is not in contact with the media group, identifies the medium type based on the current value, and raises and lowers the placement unit on the lifting unit so that the detected pressing force falls within the target range applied to the identified medium type. The media feeding device according to claim 5.

9. Further comprising a setting reception unit that receives the setting of the medium type. When the identified medium type is different from the medium type set in the setting reception unit, the control unit outputs an alert to the display unit. The media feeding device according to claim 8.

10. Further comprising a setting reception unit that receives a setting as to whether or not it is a medium type mixed mode in which a plurality of medium types are mixed in the media group. The target range includes a fixed target range applied when the medium type mixed mode is set, and an individual target range that can vary according to the medium type when the medium type mixed mode is not set. The control unit When the medium type mixed mode is set, raises and lowers the placement unit on the lifting unit so that the detected pressing force falls within the fixed target range. When the medium type mixed mode is not set, raises and lowers the placement unit on the lifting unit so that the detected pressing force falls within the individual target range. The media feeding device according to any one of claims 1 to 4.

11. A placement unit on which a media group is placed, A lifting unit that raises and lowers the placement unit, A control method for a medium feeding device, comprising: a pick roller in contact with the upper part of the medium group, and a support part applying a downward force to the pick roller, and a pick unit feeding the media in the feeding direction in order from above while applying a downward pressing force from the pick roller to the medium group. A detecting step of detecting the pressing force; A lifting control step of lifting and lowering the placement part on the lifting part so that the detected pressing force falls within a target range. A control method for a medium feeding device, including these steps.

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