Sheet feeding apparatus and image forming system

Abstract

To provide a sheet feeding apparatus capable of stably performing air-based levitation separation even for a medium having a high basis weight, by controlling a direction of air blown onto the medium in an air pickup system.SOLUTION: A sheet feeding apparatus, which levitates the uppermost sheet of a stack of multiple sheet-like media with a gas and feeds it downstream in a conveying direction, comprises: a sheet accommodating unit configured to stack and hold the multiple sheets; a gas blowing unit configured to blow gas onto the uppermost sheet; and a wind direction control unit configured to control the blowing direction of the gas from the gas blowing unit according to the characteristics of the medium.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a sheet feeding apparatus and an image forming system. [Background technology]

[0002] A sheet feeding device equipped with a sheet feeding mechanism that feeds sheet-like media (hereinafter referred to as "sheets") is known. Also known is an image forming system that links the sheet feeding device with an image forming device that forms an image on the sheet fed from the sheet feeding device.

[0003] There are several known sheet pickup methods for sheet feeding devices, including an air pickup method in which the top sheet of multiple sheets stacked in a sheet storage section is lifted by air and then the lifted sheet is adsorbed by an adsorption belt and fed.

[0004] Furthermore, in order to stably separate and feed the topmost sheet of a stack of sheets, a technology has been disclosed in which a contact member is brought into contact with the side of the sheet stack facing the air outlet of the air blowing section, the contact member is raised together with the air blowing section, and separating air sent from the air outlet to the side of the sheet stack is sent between the sheets (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0005] The technology described in Patent Document 1 can stably separate and float conventional sheets, such as copy paper with a basis weight of approximately 65 gsm (grams per square meter) or official postcards with a basis weight of approximately 209 gsm, without excessively increasing the volume / pressure of the floating air blown onto the sides of the sheet stack. However, when feeding sheets with a basis weight greater than these conventionally used sheets, the volume / pressure of the floating air must be increased to achieve stable separation and floating.

[0006] Incidentally, gift cards, which have recently become easily available for purchase at stores, are also a type of sheet-like medium. For example, a gift card has a card number, PIN (Personal Identification Number), code, etc. printed on its surface that, when entered, is reflected as points in the recipient's EC (Electronic Commerce) account and can be used for EC purchases.

[0007] These gift cards have mainly been made of plastic due to the need for durability, but they are now being replaced by paper materials in order to reduce environmental impact.However, as the need for durability for gift cards remains unchanged, cardboard, which can provide rigidity, is also being replaced by paper materials.

[0008] The basis weight of cardboard suitable for gift cards is 470 gsm or more. This is excessively large compared to the basis weight of conventionally used media. Therefore, when applying a configuration that increases the volume / pressure of floating air as disclosed in Patent Document 1, there is a problem in feeding media with a large basis weight using the air pickup method.

[0009] The present invention aims to provide a sheet feeding device that uses an air pickup method and can stably perform floating separation using air, even for media with a large basis weight, by controlling the direction in which air is blown onto the media. [Means for solving the problem]

[0010] In order to solve the above problems, one aspect of the present invention relates to a sheet feeding device that uses gas to float the topmost medium of multiple stacked sheet-like media and send it downstream in the conveying direction, and is characterized by comprising a sheet storage section that stores multiple stacked sheets, a gas blowing section that blows gas onto the topmost medium, and a wind direction control section that controls the wind direction from the gas blowing section depending on the characteristics of the medium.

[0011] According to the present invention, in the air pickup method, by controlling the direction in which air is blown onto the medium, floating and separating by air can be stably performed even for a medium with a large basis weight. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing the overall configuration of an embodiment of an image forming system according to the present invention; [Figure 2] FIG. 2 is a diagram showing an example of a sheet feeding device according to the embodiment. [Figure 3] 5A and 5B are diagrams illustrating an air pickup mechanism of the sheet feeding device according to the embodiment. [Figure 4] 5A and 5B are diagrams illustrating an air pickup mechanism of the sheet feeding device according to the embodiment. [Figure 5] 3A and 3B are diagrams illustrating a characteristic configuration of the air pickup mechanism. [Figure 6] FIG. 2 is a control block diagram of the air pickup mechanism. [Figure 7] FIG. 2 is a functional block diagram of the air pickup mechanism. [Figure 8] FIG. 4 is a diagram showing an example of a control data table applicable to the air pickup mechanism. [Figure 9] 4 is a flowchart showing a control process flow of the air pickup mechanism. [Figure 10] FIG. 10 is a diagram showing the overall configuration of another embodiment of the image forming system according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a diagram showing the overall configuration of a printing system 1 as an embodiment of an image forming system according to the present invention. The printing system 1 includes an image forming device 2 and linked paper feeders 5a and 5b.

[0014] Image forming device 2 is a digital multifunction peripheral equipped with device main body 2M having paper feed unit 3 and image forming unit 4. Device main body 2M has control unit 20 that controls image forming device 2 and connected paper feed devices 5a and 5b. Device main body 2M is configured with a touch panel or the like on its top surface, which displays various information and allows various input operations to be performed on control unit 20, such as starting execution of a print job.

[0015] 1, the paper feed unit 3 has multiple paper feed cassettes 31A, 31B, and 31C each capable of storing cut-sheet media (sheet media) in a stacked state. Each of the paper feed cassettes 31A, 31B, and 31C stores media of a sheet size selected in advance from a plurality of sheet sizes, for example, in a vertical or horizontal paper feed direction.

[0016] The paper feed section 3 has paper feed devices 30A, 30B, and 30C that sequentially pick up and separate the sheet media stored in paper feed cassettes 31A, 31B, and 31C from the top layer. The paper feed section 3 is further provided with various rollers 32 and the like, which form a paper feed path 33 that transports the sheet media fed from each of the paper feed devices 30A, 30B, and 30C to a predetermined image forming position in the image forming section 4.

[0017] Image forming unit 4 includes exposure devices (exposure units) 41K, 41Y, 41M, and 41C, and photosensitive drums 42K, 42Y, 42M, and 42C. Image forming unit 4 also includes developing devices 43K, 43Y, 43M, and 43C filled with black (K), yellow (Y), magenta (M), and cyan (C) toner. Image forming unit 4 also includes a primary transfer unit 44, a secondary transfer unit 45, and a fixing unit 46.

[0018] The exposure devices 41K, 41Y, 41M, and 41C are configured to generate laser light L for exposure of each color based on an image input from, for example, an external PC (personal computer), etc. The exposure devices 41K, 41Y, 41M, and 41C also expose the photosensitive drums 42K, 42Y, 42M, and 42C of each color with the laser light to form electrostatic latent images of each color corresponding to the read image on the surface of each photosensitive drum 42K, 42Y, 42M, and 42C.

[0019] The developing devices 43K, 43Y, 43M, and 43C supply a thin layer of toner to the corresponding photosensitive drums 42K, 42Y, 42M, and 42C so that the toner is brought into close proximity thereto, thereby developing the electrostatic latent image into a visible image with the toner.

[0020] The image forming unit 4 primarily transfers the toner images developed on the photosensitive drums 42K, 42Y, 42M, and 42C to a primary transfer unit 44, and then secondarily transfers the toner images onto a sheet medium at a secondary transfer unit 45 located close to the primary transfer unit 44. The image forming unit 4 also heats and presses the toner images secondarily transferred onto the sheet medium at a fixing unit 46 to melt the toner images, thereby fixing and recording a color image onto the sheet medium.

[0021] The image forming unit 4 has a transport path 40 that transports the sheet medium, which has been transported from the paper feed unit 3 via the paper feed path 33, to the secondary transfer unit 45. The transport timing and transport speed of the sheet medium are adjusted along this transport path 40. The sheet medium passes through the secondary transfer unit 45 and the fixing unit 46 in a state synchronized with the belt speeds at the primary transfer unit 44 and the secondary transfer unit 45, and is then discharged onto a discharge tray 49.

[0022] Below the secondary transfer unit 45 and the fixing unit 46, a switchback conveying path 47 and a reversing conveying path 48, each of which is made up of a plurality of conveying rollers, conveying guides, etc., are disposed.

[0023] When forming images on both sides of a sheet of paper P, the switchback conveying path 47 is configured to perform switchback conveyance by entering the sheet of paper P, on which an image has been fixed on any one side, from one end, and then moving it backward (in the opposite direction from when it entered).

[0024] The reversing conveying path 48 reverses the sheet medium conveyed by the switchback conveying path 47C and feeds the sheet to the conveying path 40 again.

[0025] After the image fixing process on one side of the sheet medium is completed, the sheet medium is reversed in its travel direction by the switchback conveyance path 47 and the reversing conveyance path 48, and then turned over and enters the secondary transfer nip again. The sheet medium then undergoes the secondary image transfer process and fixing process on the other side, and is then discharged onto the discharge tray 49.

[0026] The image forming device 2 is capable of feeding paper P from the paper feed section 3 in the device main body 2M via the paper feed path 33 and the conveying path 40, as well as feeding sheet media via the connecting type paper feed devices 5a and 5b via the connecting passage 500 provided on the side of the device main body 2M.

[0027] In the printing system 1, the tethered type paper feeders 5a and 5b are each configured as the tethered type paper feeder 5 shown in FIG. 2. As shown in FIG. 2, the tethered type paper feeder 5 has two paper feed trays 51, a connecting paper transport path 503 connecting connecting paths 501 and 502, and paper transport paths 504 and 505 connecting the paper feed trays 51 and the connecting path 501, respectively. The tethered type paper feeder 5 is configured to be connectable to the image forming apparatus 2 so that the connecting path 501 connects to the connecting path 500 (see FIG. 1) of the image forming apparatus 2. The tethered type paper feeder 5 can also be connected to another tethered type paper feeder 5 so that the connecting path 502 connects to the connecting path 501 of the other tethered type paper feeder 5.

[0028] In the following description, sheet media supplied from the connected paper feeders 5a and 5b will be referred to as paper P. Paper P according to this embodiment is assumed to be of various sizes and basis weights. One use for paper P is gift cards, which have recently become easily available for purchase at stores. A gift card is a type of card that can be used for purchases in electronic commerce (EC), and is reflected as points in the recipient's EC account when the recipient enters the card number, PIN (Personal Identification Number), code, etc. printed on the card.

[0029] The linked paper feeders 5a and 5b according to this embodiment can accommodate various types of paper P, but in the example described below, they will be described as mechanisms for feeding paper P with a large basis weight.

[0030] 1 includes connected paper feeders 5a and 5b as external paper feeders that feed paper P to image forming apparatus 2. Connected paper feeder 5a transports paper P loaded in paper feed tray 51 via one of paper transport paths 504 and 505, and sends the paper P to transport path 40 via connecting passage 500 of image forming apparatus 2.

[0031] The connected type paper feeder 5b transports the paper P loaded in the paper feed tray 51 within the device via either the paper transport path 504 or 505. Furthermore, the connected type paper feeder 5b sends the paper P via the connected paper transport path 503 of the connected type paper feeder 5a and the connected passage 500 of the image forming device 2 to the transport path 40.

[0032] In the printing system 1, the image forming device 2 and the linked paper feeders 5a and 5b are electrically connected when they are linked, and the paper P is fed under the control of the control unit 20. The control unit 20 may be located in either or both of the linked paper feeders 5a and 5b, and the location where the control unit 20 is installed does not matter as long as the location and connection allow the processing functions to be realized.

[0033] 2, the configuration of the connected paper feeder 5 will be described. In the connected paper feeder 5, the multiple paper feed trays 51 have a tray bottom plate 52, side fences 53 and 54, an end fence 55, a lifting mechanism 56, and a lifting motor 57.

[0034] In paper feed tray 51, a plurality of sheets of paper P are stacked on tray bottom plate 52. Tray bottom plate 52 is configured to be able to move up and down via lifting mechanism 56 driven by lifting motor 57 while sheets of paper P are stacked as a paper stack. Tray bottom plate 52, lifting mechanism 56, and lifting motor 57 constitute the lifting means of the present invention.

[0035] In paper feed tray 51, side fences 53 and 54 restrict the movement of paper sheets P stacked on tray bottom plate 52 in the width direction. End fence 55 is provided at the rear end, in the paper transport direction, of paper sheets P stacked on tray bottom plate 52, and restricts the movement of paper sheets P in the opposite direction to the paper transport direction. Elevating mechanism 56 is connected between tray bottom plate 52 and elevator motor 57, and can raise and lower tray bottom plate 52, and therefore paper sheets P on tray bottom plate 52, by rotating and driving elevator motor 57.

[0036] The linked paper feeder 5 is provided with an air pickup type paper feeder, i.e., an air feeder 60, which blows air into a stack of paper P stored in a paper feed tray 51 to float and separate the paper P, and then sucks the paper P one by one with air and sends them to paper transport paths 504 and 505.

[0037] [Air feeding device 60] Next, the air feeding device 60 provided in the linked sheet feeding devices 5a and 5b as an embodiment of the sheet feeding device according to the present invention will be described in more detail. As shown in Figures 2 to 4, the air feeding device 60 is made up of a tray bottom plate 52, side fences 53 and 54, and an end fence 55 that constitute the sheet feeding tray 51, an air feeding unit 58, and a belt feeding unit 59.

[0038] The air paper feed unit 58 is disposed downstream of the tray bottom plate 52 in the paper transport direction, and has a floating fan 58a and a separation fan 58b as blower fans that blow air onto the sheets P from the front edge in the width direction perpendicular to the paper transport direction. The floating fan 58a and the separation fan 58b blow air onto the stack of sheets P from the front edge in the width direction, thereby floating and separating sheets P in a predetermined area below the top of the sheets P. The air paper feed unit 58, which is made up of the floating fan 58a and the separation fan 58b, constitutes the air blowing means of the present invention.

[0039] The side fence 53 of the paper feed tray 51 is provided with a side fan 53a as a blower fan that blows air from the side of the paper P. Similarly, the side fence 54 is provided with a side fan 54a as a blower fan that blows air from the opposite side of the paper P. The side fans 53a and 54a blow air from both sides of the stack of paper P, making it easier for the paper P to float and separate. The side fans 53a and 54a constitute the gas blowing section of the present invention.

[0040] The air feeding device 60 according to this embodiment is characterized by side fans 53a and 54a, which will be described later.

[0041] As shown in FIGS. 3 and 4, the belt feeding unit 59 includes air suction fans 59a and 59b, a suction duct 59c, a suction chamber 59d, a pair of delivery rollers 59e and 59f, and a suction belt 59g.

[0042] Air suction fans 59a and 59b suck air from suction chamber 59d through suction duct 59c, the opening of which faces the top surface of the uppermost sheet P of the stack of sheets P stacked on tray bottom plate 52 that constitutes the sheet storage section. Air suction fans 59a and 59b are equipped with air filters 591a and 591b that remove paper powder, calcium carbonate, dust, and dirt so that they are not discharged outside the machine.

[0043] The suction belt 59g is configured as an endless belt made of, for example, rubber, stretched between a pair of feed rollers 59e and 59f facing the opening of the suction chamber 59d. The sheet P is adsorbed onto the suction belt 59g by air sucked in by air suction fans 59a and 59b. The pair of feed rollers 59e and 59f are driven to rotate by a belt drive motor 59h, which will be described later, and transport the suction belt 59g, to which the sheet P is adsorbed, downstream in the paper transport direction.

[0044] With the above-described configuration, in the belt paper feed unit 59, the sheets P that have been floated and separated by the air blown from the air paper feed unit 58 are sucked in through the suction duct 59c, and the sheets P are sucked in one by one, starting from the top, by the suction belt 59g. Thereafter, in the belt paper feed unit 59, the pair of feed rollers 59e, 59f are driven to rotate, and the suction belt 59g rotates, and the sheets P sucked on the circumferential surface of the suction belt 59g are fed downstream in the paper conveyance direction.

[0045] In this manner, the air suction fans 59a and 59b that suck air through the suction duct 59c and the belt paper feed unit 59 having the suction belt 59g constitute the paper suction and transport means of the present invention.

[0046] In air feeding device 60, in controlling the feeding operation of paper P, side fans 53a, 54a, floating fan 58a, separation fan 58b, and air suction fans 59a, 59b are selectively driven to rotate at their respective start timings in accordance with the paper feeding timing. This control is performed by air feeding control unit 21 included in control unit 20. The configuration of air feeding control unit 21, which constitutes the air direction control unit of the present invention, will be described later.

[0047] In the air feeding device 60, when the lifting fan 58a and the separation fan 58b start to rotate, the air generated by their respective rotations is blown onto the leading edge of the paper P through different duct paths as separation air for separating the paper P and lifting air for lifting the entire stack of paper.

[0048] In the air feeding device 60, when the side fans 53a and 54a provided on the side fences 53 and 54, respectively, start to rotate, side air is blown onto the sides of the paper P, and the entire stack of paper sheets is floated in the same manner as the floating fan 58a.

[0049] In air feeding device 60, when air suction fans 59a and 59b start to rotate, suction air is applied through suction duct 59c to create a negative pressure in suction chamber 59d in belt feeding unit 59, thereby sucking in the topmost sheet P of the stack of sheets P. When the topmost sheet P is adsorbed to suction belt 59g, suction belt 59g is driven to rotate, and the sheet P is transported to device body 2M of image forming device 2.

[0050] In the above paper feeding operation, the air volume of side fans 53a, 54a, floating fan 58a, separation fan 58b, and air suction fans 59a, 59b and the switching between air blowing and shutting off are automatically controlled by control unit 20 by determining paper feeding parameters based on the paper type, paper thickness, and paper size.

[0051] [Side Fan 53a, 54a] Next, the side fans 53a and 54a, which have a characteristic configuration in this embodiment, will be described. As already explained, the side fans 53a and 54a are configured to blow air against the side portions of the stacked paper sheets P, and are arranged at positions facing each other with the paper sheets P sandwiched between them in a direction perpendicular to the conveyance direction of the paper sheets P.

[0052] 5 is a plan view from above of the sheet storage section in which side fences 53 and 54 are arranged. As shown in FIG. 5, side fans 53a and 54a are arranged in side fences 53 and 54, respectively. Each of side fans 53a and 54a has a plurality of gas outlets. For example, side fan 53a is provided with a left front outlet 531 and a left central outlet 532. Side fan 54a is provided with a right front outlet 541 and a right central outlet 542.

[0053] The side fans 53a and 54a each have a plurality of gas outlets, two of which are arranged along the feed direction C (conveyance direction) of the paper P. The left front outlet 531 and the right front outlet 541 are each arranged near the downstream end of the paper P in the conveyance direction. The left central outlet 532 and the right central outlet 542 are each arranged in a position that corresponds to, for example, approximately the middle of the length of the paper P in the conveyance direction of the paper P. The relative positions of the left central outlet 532 and the right central outlet 542 vary depending on the length of the paper P.

[0054] The left front air outlet 531 and the right front air outlet 541 are each attached by a rotation axis 5411 whose axis is the stacking direction of the paper sheets P, so that the air outlet angle relative to the side of the stacked paper sheets P can be changed. The air outlet angle W, which corresponds to the air direction from each of the left front air outlet 531 and the right front air outlet 541, is controlled by the air feed control unit 21. The left front air outlet 531 and the right front air outlet 541 can be switched to one of two air directions: for example, as shown in FIG. 5(a), a state in which the air direction is set to the direction inclined relative to the transport direction of the paper sheets P; and as shown in FIG. 5(b), a state in which the air direction is set to the direction perpendicular to the side of the paper sheets P.

[0055] For example, when the basis weight of the paper P is less than a predetermined threshold, that is, when the basis weight of the paper P is such that it can float using conventional technology, gas (air) is blown toward the upstream side in the transport direction, as shown in Fig. 5(a). By blowing in this direction, the air blown toward the paper P can escape toward the transport direction of the paper P, suppressing the occurrence of turbulence and the like, and maintaining a state in which the floating of the paper P is not easily hindered, allowing the uppermost paper P (topmost medium) to be separated.

[0056] Furthermore, when the basis weight of the paper P is equal to or greater than a predetermined threshold, i.e., when the paper P is heavier than the basis weight of conventional paper P and is classified as "ultra-thick paper," air is blown perpendicular to the side of the paper P, as shown in FIG. 5(b). This allows even paper P with a large basis weight to be sufficiently lifted. As a result, it is possible to prevent poor paper P feeding, and for paper P with a small basis weight, the airflow generated by the side air can be stabilized to ensure proper feeding.

[0057] <Hardware configuration> Fig. 6 is a block diagram showing an example of the hardware configuration of air feeding control unit 21 that controls air feeding device 60. As shown in Fig. 6, air feeding control unit 21 has a CPU (Central Processing Unit) 210, ROM (Read Only Memory) 220, RAM (Random Access Memory) 230, HDD (Hard Disk Drive) / SSD (Solid State Drive) 240, and I / F (Interface) 250. These are connected to each other via a system bus so that they can communicate with each other.

[0058] The CPU 210 executes control processes including various types of arithmetic processing.

[0059] The ROM 220 is a non-volatile memory that stores programs used to drive the CPU 210, such as an IPL (Initial Program Loader).

[0060] The RAM 230 is a volatile memory used as a work area for the CPU 210 .

[0061] The HDD / SSD 240 is a non-volatile memory that can store various information, programs, and the like used for control by the air paper feed control unit 21.

[0062] I / F 250 is an interface for communicating between air paper feed control unit 21 and devices or apparatuses other than air paper feed control unit 21. I / F 250 can also communicate with devices or apparatuses other than air paper feed control unit 21 via a network or the like. Devices other than air paper feed control unit 21 include operation display unit 25 and drive unit 260. Devices other than air paper feed control unit 21 include an external PC (Personal Computer) and an external server.

[0063] The operation display unit 25 can accept operations by an operator for the printing system 1. The operation display unit 25 can also be configured to include, for example, a touch panel, buttons, a keyboard, etc. The operation display unit 25 may also function as a notification unit that notifies the airflow direction set in the side fans 53a, 54a. In this case, the operation display unit 25 notifies information that allows the operator (user) to easily visually determine whether the airflow direction is perpendicular to the side of the paper P or inclined toward the upstream side of the paper P in the transport direction.

[0064] The drive unit 260 is configured with an electric circuit, etc. The drive unit 260 is connected to the air feeding device 60 so as to be able to control the drive of the side fans 53 a, 54 a provided in the air feeding device 60 and the drive of the air blowing direction control motor 270 serving as an air outlet rotation unit that performs a rotational operation to switch the blowing direction of the side fans 53 a, 54 a.

[0065] <Functional configuration> 7 is a block diagram showing an example of the functional configuration of a portion related to the air levitation unit of the printing system 1. As shown in the figure, the air feeding device 60 has a reception unit 211, a display control unit 212, an air levitation unit control unit 213, a determination unit 214, a sheet information acquisition unit 215, and a storage / readout unit 216.

[0066] These units are functions or means that are realized when any of the components shown in Fig. 6 operates in response to commands from CPU 210 in accordance with the control device program loaded on RAM 230. Air supply device 60 also has a storage unit constructed from ROM 220, HDD / SSD 240, etc. shown in the previous figure.

[0067] The reception unit 211 is mainly realized by the processing of the CPU 210 on the operation display unit 25, and receives various selections or inputs from the operator.

[0068] The display control unit 212 is mainly realized by the processing of the CPU 210, and causes various screens to be displayed on a display unit such as the operation display unit 25.

[0069] The air levitation unit control unit 213 is mainly realized by the processing of the CPU 210, and controls the driving of the air supply fans (side fans 53a, 54a) equipped in the air feeding device 60 via the driving unit 260, and the driving of the air blowing direction control motor 270.

[0070] The determination unit 214 is realized by the processing of the CPU 210 and performs various determinations.

[0071] The sheet information acquisition unit 215 is mainly realized by the processing of the CPU 210 , and acquires sheet information from the information accepted by the acceptance unit 211 .

[0072] The storage / readout unit 216 is mainly realized by the processing of the CPU 210, and stores various data (or information) in the storage unit and reads out various data (or information) from the storage unit.

[0073] Each of the above functions can also be realized by one or more processing circuits. Note that the term "processing circuit" here includes devices such as an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), and conventional circuit modules designed to execute each of the above functions. Some of the above functions provided by air paper feed control unit 21 can also be realized by external devices such as an external PC or external server that are communicatively connected to air paper feed control unit 21. Furthermore, some of the above functions provided by air paper feed control unit 21 can also be realized by distributed processing between the control unit and these external devices.

[0074] <Sheet information management table> Fig. 8 is a conceptual diagram showing an example of a sheet information management table. A sheet information management database (DB) made up of a sheet information management table Tb801 as shown in Fig. 8 is constructed in the storage unit 217 shown in Fig. 7. The sheet information management table Tb801 is a group of information that associates characteristic information such as the basis weight and size of the paper P with an instruction to switch the direction of air blown onto the paper P.

[0075] For example, in the sheet information management table Tb801 shown in FIG. 8, the direction of the air blown onto the sheet P is set in advance based on actual measurement data, etc., so that as the basis weight and size of the sheet P increase, the direction of the air blown onto the sheet P changes from flag "0" (air blown diagonally) to flag "1" (air blown orthogonally). Note that the sheet information management table shown in FIG. 8 is an example and is not limited to this. The basis weight and size of the sheet P may be further subdivided. Furthermore, the direction of the air blown onto the sheet P may not only be switched between two types, "diagonal direction" and "orthogonal direction," but may also be subdivided so that the "diagonal direction" can be switched between different inclination angles.

[0076] Furthermore, for example, if the size of the paper P used is limited to one type or a narrow range, a sheet information management table Tb801 may be created that links the basis weight of the paper P with the air blowing direction, so that the direction of the air to be blown onto the paper P can be determined based solely on the information on the basis weight of the paper P.

[0077] <Processing or Operation of the Embodiment> 9 is a flowchart showing an example of the flow up to notification to place cardboard on the cardboard tray. When executing image formation (printing) in the printing system 1, the operator first selects the paper P to be used in image formation. The paper P selection operation may be performed by any method, such as a method in which the user inputs the selection via an input interface realized by the operation display unit 25.

[0078] When a selection operation of the paper P is performed via the operation display unit 25, the reception unit 211 receives the selection operation (step S901).

[0079] When the reception unit 211 receives a paper selection operation, the sheet information acquisition unit 215 acquires paper information corresponding to the selected paper P from the sheet information stored in the memory unit 217 via the storage / readout unit 216 (step S902).

[0080] Next, the determination unit 214 determines whether the sheet P is cardboard or not (step S903) based on the sheet information acquired by the sheet information acquisition unit 215. If the determination result in step S903 is "YES" (cardboard is used), the display control unit 212 notifies the user to place (load) the cardboard to be used for image formation on a cardboard tray (step S904).

[0081] The notification may be made in any manner that can be recognized by the operator, such as by displaying a message on the operation display unit prompting the operator to place the paper in the thick paper feed tray 51, or by illuminating a warning lamp provided on the thick paper feed tray 51. If the determination result in step S903 is "NO" (thick paper will not be used), there is no need to make the notification as described above, and the process is completed.

[0082] [Straight transport path configuration] 10 is a diagram illustrating the relative positional relationship between the position of the air feeding device 60 provided in the printing system 1 and the image forming unit 4 (secondary transfer unit 45) provided in the printing system 1. As shown in FIG. 10, the air feeding device 60 is arranged in the conveying path at a height position substantially the same as the height position at which the configuration for forming an image on the paper P by the image forming unit 4 (secondary transfer unit 45) is arranged.

[0083] By configuring in this way, it is possible to minimize the degree of curvature of the transport path for the highly rigid, extra-thick paper P, so that the paper P can be transported in a straight line.

[0084] The present invention is not limited to the above-described exemplary embodiments, and various modifications are possible without departing from the technical gist thereof. The present invention covers all technical matters included in the technical concept described in the claims. The above-described embodiments are preferred examples, but a person skilled in the art can realize various modifications from the disclosed content. Such modifications are also included in the technical scope described in the claims.

[0085] The control method described above may be realized, for example, by a program. That is, the control method is a method executed by a computer by causing an arithmetic unit, a storage unit, an input unit, an output unit, and a control unit to cooperate with each other based on the program. The program may be written to a storage unit or a storage medium and distributed, or distributed via a telecommunications line, etc.

[0086] For example, aspects of the present invention are as follows. <1> Aspect 1 is a sheet feeding device that uses gas to float the topmost medium of multiple stacked sheet-like media and send it downstream in the conveying direction, and is characterized by comprising a sheet storage section that stores multiple stacked sheets, a gas blowing section that blows gas onto the topmost medium, and a wind direction control section that controls the wind direction from the gas blowing section depending on the characteristics of the medium. <2> In a second aspect of the present invention, in the first aspect, the gas blowing unit includes a gas blowing outlet and an outlet rotation unit that rotates the direction of the gas blowing outlet around the stacking direction of the sheets as an axis, and the airflow direction control unit rotates the gas blowing unit so that the airflow direction toward the side of the medium is either perpendicular to the side or inclined to the side, depending on the characteristics of the medium. <3> In aspect 3, in aspect 2, the wind direction control unit switches the wind direction so that the wind direction is in the perpendicular direction when the basis weight of the medium is equal to or greater than a predetermined threshold, and switches the wind direction so that the wind direction is in the inclined direction when the basis weight of the medium is less than the predetermined threshold. <4> A fourth aspect is related to the third aspect, wherein the airflow direction control unit rotates the gas blowing unit so as to face the upstream side in the transport direction of the medium when the airflow direction is in the inclined direction. <5> Aspect 5 is a configuration in which, in any of aspects 1 to 4, a notification unit is provided that notifies the user of the direction of the wind direction, and the wind direction control unit controls the notification unit to provide a notification indicating the type of wind direction according to the characteristics of the medium. <6> A sixth aspect is the fifth aspect, wherein the notification unit is an operation display unit that also serves as an input interface through which the user inputs characteristic information of the medium. <7> A seventh aspect is the fifth or sixth aspect, wherein the notification unit is included in the sheet storage unit. <8> Aspect 8 is an image forming system having an image forming device that forms an image on a sheet-like medium, and a sheet feeding device of any of aspects 1 to 7 that separates and feeds the topmost of multiple media stacked to transport the media to the image forming device. <9> Aspect 9 is an aspect of aspect 8, in which the sheet storage section is provided in multiple locations, and the gas blowing section is provided in one storage section in which the height position of the transport path for transporting the medium is approximately the same in the transport direction relative to the image forming device. [Explanation of symbols]

[0087] 1: Printing system 2: Image forming device 3:Paper feed section 4: Image forming unit 5, 5a, 5b: Connected paper feeder 51: Paper tray 52: Tray bottom plate 53, 54: Side fence 53a, 54a: Side fan 531:Left front air outlet 532: Left center air outlet 541: Right front air outlet 542: Right center air outlet 55: End fence 56: Lifting mechanism 57: Lifting motor 58: Air feed unit 59: Belt feed unit 60: Air supply device P: Paper (sheet media) [Prior art documents] [Patent documents]

[0088] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-132587

Claims

1. A sheet feeding device that uses gas to float the topmost medium of a stack of sheet-like media and sends it downstream in a conveying direction, a sheet storage section for storing a plurality of sheets; a gas blowing unit that blows the gas onto the uppermost medium; a wind direction control unit that controls the wind direction of the gas blowing unit according to the characteristics of the medium; A sheet feeding device comprising:

2. the gas blowing unit includes a gas blowing outlet and a blowing outlet rotating unit that rotates the direction of the gas blowing outlet around an axis corresponding to the stacking direction of the sheets, The airflow direction control unit rotates the gas blowing unit so that the airflow direction toward the side surface of the medium is either perpendicular to the side surface or inclined to the side surface, depending on the characteristics of the medium. The sheet feeding device according to claim 1 .

3. The airflow direction control unit is When the basis weight of the medium is equal to or greater than a predetermined threshold, the wind direction is set to the orthogonal direction; When the basis weight of the medium is less than a predetermined threshold, the airflow direction is switched so that the airflow direction is in the tilt direction. The sheet feeding device according to claim 2 .

4. The airflow direction control unit is When the airflow direction is in the inclined direction, the gas blowing unit is rotated so as to face the upstream side in the transport direction of the medium. The sheet feeding device according to claim 3 .

5. a notification unit that notifies a user of the wind direction; the wind direction control unit controls the notification unit to perform a notification indicating the type of wind direction according to the characteristics of the medium. The sheet feeding device according to claim 1 .

6. the notification unit is an operation display unit that also serves as an input interface through which a user inputs characteristic information of the medium; The sheet feeding device according to claim 5 .

7. The notification unit is included in the sheet storage unit. The sheet feeding device according to claim 5 .

8. an image forming device that forms an image on a sheet-like medium; a sheet feeding device according to claim 1 , which separates and feeds the topmost of a plurality of stacked media to transport the media to the image forming device; An image forming system comprising:

9. The sheet storage unit includes a plurality of the sheet storage units, the gas blowing unit is provided in one accommodation unit that is at substantially the same height position as a transport path for transporting the medium in the transport direction relative to the image forming device; The image forming system according to claim 8 .

Images