Sheet feeding device and image forming apparatus having sheet feeding device

Abstract

To solve a problem of a risk that the productivity of an apparatus may be lowered by performing an air blowing operation when only a single sheet is placed on a sheet support part.SOLUTION: A sheet feeding device comprises: a sheet support part; a feeding part; an air blowing part; a detection part; a feeding mode setting part that sets an air feeding mode in which air separation is executed to separate sheets and then the sheets are fed, and a feeding mode in which the sheets are fed without executing the air separation; and a control part that controls feeding in the mode set by the feeding mode setting part. The control part, when a predetermined number of feeding jobs in the air feeding mode that is determined to have no sheet by the detection part is continuously executed after feeding a single sheet placed on the sheet support part, prompts a user, before executing subsequent feeding jobs, to select whether feeding is to be executed in the air feeding mode or in the feeding mode, and feeds the sheets based on the selection.SELECTED DRAWING: Figure 11

Description

[Technical Field]

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

[0002] Image forming apparatuses such as copiers, facsimiles, and printers are equipped with a sheet feeding device for setting a stack of sheets to be supplied to an image forming unit where an image is formed. Examples of the sheet feeding device include a feeding cassette unit provided at the bottom of the image forming apparatus main body and a manual feeding unit provided on the side of the image forming apparatus main body.

[0003] In recent years, there has been an increasing demand for forming images on a variety of sheets, and sheets with smooth surfaces, such as coated paper, are often used as recording materials. When a stack of such smooth-surfaced sheets is set in a sheet feeding device, the sheets tend to adhere closely to each other, making it difficult to separate and feed a single sheet from the stack. For this reason, Patent Document 1 discloses a device that blows air between the sheets to lift them up and separate the sheets. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 4-23747 Summary of the Invention [Problem to be solved by the invention]

[0005] When a single sheet is placed on the sheet support section, there is no need to perform the air blowing operation because the sheets do not stick to each other. However, in the sheet feeding device described in Patent Document 1, the number of sheets placed on the sheet support section is unknown. Therefore, the air blowing operation must be performed as if multiple sheets were placed. In this case, even if only one sheet is actually placed on the sheet support section, the air blowing operation must be performed every time, which could reduce the productivity of the device.

[0006] Therefore, an object of the present invention is to prevent a decrease in productivity of the apparatus by not performing the air blowing operation when only one sheet is placed on the sheet support section. [Means for solving the problem]

[0007] One aspect of the present invention is a sheet feeding device including a sheet support section that supports a sheet, a feeding section that feeds the sheet supported by the sheet support section, a blower section that blows air toward an end of the sheet supported by the sheet support section, a detection section that detects the presence or absence of a sheet placed on the sheet support section, a feeding mode setting section that sets an air feeding mode in which the feeding section feeds the sheet after the air blower blows air to separate the sheet, and a feeding mode in which the feeding section feeds the sheet without performing the air separation, and a control unit that controls feeding in the mode set by the feeding mode setting unit, wherein when a feeding job in the air feeding mode has been executed a predetermined number of times in succession, after feeding one sheet placed on the sheet support unit, and the detection unit determines that there is no sheet, the control unit prompts the user to select whether to execute feeding in the air feeding mode or the feeding mode before executing a feeding job subsequent to the feeding job, and feeds the sheet based on the selection. [Effects of the Invention]

[0008] According to the present invention, by prompting the user to decide whether to blow air when there is only one sheet placed on the sheet stacking section, it is possible to reduce the decrease in productivity of the apparatus. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a control block diagram of a sheet feeding device according to an embodiment of the present invention. [Figure 3] FIG. 2 is a schematic diagram showing the configuration of a manual feeding unit according to the embodiment of the present invention. [Figure 4] 10 is a schematic diagram showing a state in which an air handling operation is performed in the manual feed unit according to the embodiment of the present invention. [Figure 5] 10 is a flowchart illustrating sheet feeding control by air blowing according to an embodiment of the present invention. [Figure 6] FIG. 4 is a setting screen diagram of sheet information according to the embodiment of the present invention. [Figure 7] 10 is a flowchart illustrating a setting of sheet information and air blowing according to an embodiment of the present invention. [Figure 8] 10 is a table showing whether or not air blowing is required according to an embodiment of the present invention. [Figure 9] FIG. 10 is an explanatory diagram illustrating the selection of a handling mode according to an embodiment of the present invention. [Figure 10] 10 is a flowchart showing selection of a handling mode according to an embodiment of the present invention. [Figure 11] 10A and 10B are screen views showing a flowchart and settings for air blowing according to an embodiment of the present invention. [Figure 12] 10 is a flowchart showing a method for setting a single-sheet loading counter according to an embodiment of the present invention. [Figure 13] FIG. 10 is a setting screen diagram for determining whether to place one sheet according to the embodiment of the present invention. [Figure 14] 3 is a flowchart illustrating a user authentication method according to an embodiment of the present invention. [Figure 15] FIG. 4 is a diagram showing a user authentication screen according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Embodiment> Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a cross-sectional view of an image forming system according to this embodiment. As shown in Fig. 1, an image forming system 600 includes an image forming apparatus 201 and a feeding deck 500 connected to the image forming apparatus 201. The feeding deck 500 as a sheet feeding device is connected to the right side of the image forming apparatus 201 in Fig. 1, and is configured to be able to feed sheets S to the image forming apparatus 201.

[0011] <Image forming device> In Fig. 1, 201 is an image forming apparatus, 201A is an image forming apparatus main body, and 201B is an image forming unit that forms an image on a sheet. 202 is an image reading device installed horizontally above the image forming apparatus main body 201A, and the image forming apparatus main body 201A is equipped with the image forming unit 201B. In addition, an ejection space V for ejecting sheets is formed between the image reading device 202 and the image forming apparatus main body 201A. Note that an operation unit 700 composed of a touch panel or the like that can display a screen is disposed above the image forming apparatus main body 201A.

[0012] Image forming unit 201B, which is an image forming means, is provided in the center of image forming apparatus main body 201A in the vertical direction and mainly includes a laser scanner 210, a process cartridge 211, and a toner cartridge 215. Image forming unit 201B also includes an intermediate transfer unit 201C and a fixing unit 201E. Process cartridge 211 is a four-drum full-color type and includes four color process cartridges (211Y, 211M, 211C, and 211K) for yellow (Y), magenta (M), cyan (C), and black (K). Each process cartridge 211 includes a photosensitive drum 212, a charger 213, which is charging means, and a developer 214, which is developing means.

[0013] An intermediate transfer unit 201C is disposed above the process cartridge 211. The intermediate transfer unit 201C includes an intermediate transfer belt 216 wound around a drive roller 216a and a tension roller 216b. A primary transfer roller 219 is disposed inside the intermediate transfer belt 216 and abuts against the intermediate transfer belt 216 at a position facing the photosensitive drum 212. The intermediate transfer belt 216 is rotated in the direction indicated by the arrow by the drive roller 216a, which is driven by a drive unit (not shown). The negative color toner images on the photosensitive drums are superimposed and transferred to the intermediate transfer belt 216 in the order of YMCK by the primary transfer roller 219. A secondary transfer roller 217 is disposed opposite the drive roller 216a of the intermediate transfer unit 201C and transfers the color image formed on the intermediate transfer belt to a sheet P. The intermediate transfer belt 216 and the secondary transfer roller 217 constitute a secondary transfer section 201D. The toner cartridge 215 is disposed above the intermediate transfer unit 201C.

[0014] Furthermore, above the secondary transfer roller 217, a fixing unit 201E having a pressure roller 220a and a heating roller 220b is disposed.

[0015] In addition, a first discharge roller pair 225a, a second discharge roller pair 225b, and a double-sided reversing unit 201F are arranged in the upper left of the fixing unit 201E. The double-sided reversing unit 201F is provided with a reversing roller pair 222 that can rotate forward and backward, and a re-conveying path R that conveys the sheet with an image formed on one side to the image forming unit 201B again.

[0016] A sheet feeding unit 230 is provided at the bottom of the image forming apparatus main body 201A, which feeds set sheets S to the image forming section 201B. The sheet feeding unit 230 includes a feeding cassette 1 that stores sheets, and a sheet feeding section 506 that feeds the sheets S stored in the feeding cassette 1. The sheet feeding section 506 includes a pickup roller 2, and a feed roller 3 and a retard roller as a separation means that separates sheets S that have been fed from the pickup roller 2 and have been fed in a multi-fed state.

[0017] Further, a manual feed section 235 that feeds set sheets S to the image forming section 201B is provided on the right side surface of the image forming apparatus main body 201A in FIG. 1. The manual feed section 235 includes a manual tray 6 that supports the sheets S, and similarly to the sheet feeding unit 230, includes a sheet feeding means and a separation means. Further, a feed deck 500 that feeds set sheets S to the image forming section 201B is provided below the manual feed section 235 on the right side surface of the image forming apparatus main body 201A in FIG. 1. The manual feed section 235 will be described in detail later.

[0018] Next, the image forming operation of the image forming apparatus 201 will be described. First, image information of an original is read by the image reading device 202. After image processing, this image information is converted into an electrical signal and transmitted to the laser scanner 210 of the image forming unit 201B. In the image forming unit 201B, the surface of the photosensitive drum 212, the surface of which has been uniformly charged to a predetermined polarity and potential by the charger 213, is sequentially exposed to laser light. As a result, electrostatic latent images of yellow, magenta, cyan, and black are sequentially formed on the photosensitive drum of each process cartridge 211, respectively.

[0019] Thereafter, this electrostatic latent image is developed and visualized with toner of each color, and the toner images of each color on each photosensitive drum are transferred in order onto the intermediate transfer belt 216 in a superimposed manner by a primary transfer bias applied to the primary transfer roller 219. As a result, a toner image is formed on the intermediate transfer belt 216.

[0020] Meanwhile, the sheet S fed by the feed rollers 3 of the sheet feeding unit 230 is conveyed to a pair of registration rollers (hereinafter referred to as the registration roller pair) 240, which consists of a drive roller and a driven roller. At this time, the driving of the registration roller pair 240 is stopped, and the leading edge of the sheet S abuts against the registration roller pair 240. As a result, the leading edge of the sheet S is made to follow the nip of the registration roller pair 240. Thereafter, as the sheet S continues to be conveyed by the feed rollers 3, a flexure (loop) is formed in the sheet S, and when a predetermined loop amount is reached, the registration roller pair 240 is driven. As a result, the skew of the sheet S is corrected by the registration roller pair 240, and the sheet S with the skew corrected is conveyed to the secondary transfer portion 201D by the registration roller pair 240. Subsequently, in the secondary transfer portion 201D, the toner images are transferred all at once onto the sheet S by a secondary transfer bias applied to the secondary transfer roller 217. The sheet S onto which the toner image has been transferred is then conveyed to the fixing section 201E, where the toner of each color is melted and mixed under heat and pressure, and fixed onto the sheet S as a color image.

[0021] Thereafter, the sheet S on which the image has been fixed is discharged into the discharge space V by a first discharge roller pair 225a and a second discharge roller pair 225b provided downstream of the fixing unit 201E, and is stacked on a stacking unit 223 formed on the bottom surface of the discharge space V. When images are formed on both sides of the sheet S, after the images are fixed, the sheet S is transported to a re-conveyance path R by a reversing roller pair 222, and is transported again to the image forming unit 201B.

[0022] As described above, the image forming process for forming an image and the sheet transport process for transporting a sheet to form an image on it are linked together to form an image on the sheet.

[0023] <Manual feed section> Next, the manual feeding unit 235 as a sheet feeding device will be described in detail with reference to FIGS.

[0024] First, the control configuration for sheet feeding in the manual feed unit will be described with reference to the control block diagram in FIG. 2. The control unit 100 according to this embodiment is provided in, for example, the image forming apparatus 201, and includes a CPU 101, a ROM 102, and a RAM 103. The control unit 100 is a control means that controls the image forming apparatus 201, the feed deck 500, and the manual feed unit 235 in an integrated manner. The control unit 100 is connected to a host device 900 and an operation unit 700, and performs signal processing and sequence control for various process devices while exchanging information with them. The host device 900 is an external device such as a personal computer, image scanner, or facsimile machine.

[0025] ROM 102 stores a user name and a password used in a user authentication process (described later). RAM 103 stores sheet information for feed cassette 1, feed deck 500, and manual feed tray 6, such as sheet size and sheet type, which is set using a sheet information setting method (described later). Controller 100 is connected to fan controller 402, feed motor 520, which drives pickup roller 501, torque measurement unit 520a, which measures the motor torque of feed motor 520, and feed sensor 505. Torque measurement unit 520a measures the motor torque of feed motor 520. However, torque measurement unit 520a may be, for example, a current sensor that detects the value of a current flowing through feed motor 520 or a torque sensor that detects the torque generated in pickup roller 501. Torque measurement unit 520a may have any specific configuration as long as it can measure the motor torque of feed motor 520. Fan controller 402 controls the rotation of fans 511a and 511b while simultaneously detecting malfunctions. Whether or not a malfunction has occurred can be determined by counting the number of rotations of the fan and determining whether or not the intended number of rotations has been reached.

[0026] 3 is a schematic diagram showing the configuration of the manual feed unit 235 according to this embodiment. The manual feed unit 235 includes a manual tray 6 as a sheet storage unit, and a sheet feed unit 506 that feeds sheets and separates the sheet stack. The sheet feed unit 506 includes a pickup roller 501 as a feed roller that contacts the top sheet of the sheet stack and feeds the top sheet. The sheet feed unit 506 also includes a feed roller 502 and a retard roller 503 as a separation unit that separates the sheet S fed from the pickup roller 501. In the manual feed unit 235, a pull-out roller 504 is disposed downstream of the feed roller 502 in the sheet feeding direction to pull out the sheet S from the feed roller 502 and feed it to the image forming apparatus 201. Furthermore, a feed sensor 505 serving as a sheet detection unit is disposed between the feed roller 502 and the pull-out roller 504 in the sheet feeding direction, that is, downstream in the feeding direction of the sheet feeding unit 506. This feed sensor 505 detects the passage of the sheet S by outputting a signal depending on the presence or absence of the sheet S.

[0027] 3, the manual feed tray 6 is provided with a manual feed tray base 515 and a lifter plate 514 as a sheet support portion that supports and stacks a sheet bundle consisting of a plurality of sheets S. The lifter plate 514 is also provided with a sheet presence / absence detection sensor 401 as a detection portion, which can determine whether a sheet bundle has been stacked on the lifter plate 514. The height position of the lifter plate 514 is controlled by an elevation mechanism (not shown) in accordance with the amount of stacked sheets S. The manual feed tray 6 is also provided with side edge restriction plates 511 and 512, which restrict the positions of the widthwise ends (side edges of the sheets) of the sheets S set on the lifter plate 514.

[0028] Furthermore, side edge regulating plates 511 and 512 are provided with air blowing sections 511A and 512A, respectively, as air handling sections. Air blowing section 511A of side edge regulating plate 511 has fan 511b, which is an air blowing section driven by fan motor 511M (see FIG. 2), and blowing nozzle 511a, which guides the air blown from fan 511b and blows it from the side of the sheet stack. Similarly, air blowing section 512A of side edge regulating plate 512 has fan 512b, which is driven by fan motor 512M (see FIG. 2), and blowing nozzle 512a, which guides the air blown from fan 512b and blows it from the side of the sheet stack. In addition, the side end regulating plates 511, 512 are provided with floating suppression plates 511c, 512c near the blowing nozzles 511a, 512a to prevent the sheet S, to which air is blown, from floating up and climbing over the side end regulating plates 511, 512.

[0029] Next, the state of the sheets S when air is blown from the side edges of the sheet stack by the air blowing units 511A and 512A will be described with reference to Fig. 4. Fig. 4 is a schematic diagram showing a state in which an air blowing operation by a fan (hereinafter referred to as "air blowing operation") is performed in the manual feed unit 235 according to this embodiment.

[0030] As shown in FIG. 4, air is blown toward the side of the sheet stack from fans 511b and 512b of air blowing units 511A and 512A as indicated by arrows A1 and A2. As a result, several to several tens of sheets S located at the top of the stack of sheets are raised. The uppermost raised sheet contacts lift-up suppression plates 511c and 512c, thereby restricting the lift-up of sheets S. This air-blowing action reduces the adhesion between sheets. Even sheets S having a smooth surface, such as coated paper, can be separated and fed one by one by feed roller 502 and retard roller 503.

[0031] <Air-clearing sheet feeding control by manual feeding unit> Next, the sheet feeding control according to this embodiment will be described with reference to the flowchart in Fig. 5. The control unit 100 starts sheet feeding control to feed, for example, 15 sheets as the number of sheets required for printing in the image forming apparatus 201.

[0032] First, the number of sheets to be fed stored in RAM 103 is set to 0 (S1). Next, an air blowing execution determination process is performed to determine whether an air blowing operation is necessary (S2), and an air blowing execution flag is checked (S3). The "air blowing execution determination process" and the "air blowing execution flag" will be described later.

[0033] If the air blowing execution flag is ON, the air blowing operation is necessary, so the air blowing operation is started in S4 (Yes in S3). If the air blowing execution flag is OFF, the air blowing operation is not necessary, so the paper feed operation is started in S7 without the air blowing operation (No in S3).

[0034] If air blowing is required (Yes in S3), the fan motors 511M and 512M (see FIG. 2) of the air blowing units 511A and 512A are driven in S4 to start blowing air onto the sides of the sheet stack. As a result, several to several dozen sheets S at the top of the sheet stack are separated and floated, while the floatation suppression plates 511c and 512c prevent the sheets S from floating up (see FIG. 4), reducing the adhesion between the sheets. Since the fan motors 511M and 512M start rotating from a stopped state, a predetermined time, such as 10 seconds, is preset as the time it takes for the desired number of rotations (rotational speed) to be reached and for the floating and separation of the sheets S to stabilize. The air blowing operation continues until the predetermined time has elapsed (No in S5), and once the predetermined time has elapsed (Yes in S5), the air blowing operation is stopped (S6), i.e., the fan motors 511M and 512M are turned off. The sheets S that were in a floating state try to return to the state of the sheet stack before floating as the air between the sheets is released, but since the adhesive force between the sheets remains reduced until the sheets return to the state of the sheet stack, the feeding operation of the sheets S is started (S7).

[0035] The start of the feeding operation refers to the feeding of sheet S by the pickup roller 501 being driven by the feeding motor 520 to rotate while in contact with the uppermost sheet S in the sheet stack. After that, if multiple sheets S are fed, they are separated in a separation section made up of a feed roller 502 and a retard roller 503, and a series of operations are performed in which the passage of the sheets is detected by a feeding sensor 505. Then, a one-sheet placement determination process (S8) described later is performed, and the feeding operation is repeated until the feeding of the required number of sheets S, for example, 15 sheets, is completed (No in S9), and when the feeding of the required number of sheets is completed (Yes in S9), the sheet feeding control ends.

[0036] <Setting the air blowing execution flag by setting the sheet information> Setting of sheet information such as the size, type, and basis weight of the sheet set in the manual feed tray 6 and the air blowing execution flag based on the sheet information setting will be described with reference to FIGS. 6, 7, and 8. FIG.

[0037] Sheet settings are made from an operation unit 700 as a sheet type setting unit. Fig. 6(a) is a diagram showing the operation unit 700 in the image forming apparatus of Fig. 1. The operation unit 700 is provided with a start key 702 for starting an image forming operation, a stop key 703 for interrupting the image forming operation, numeric keys 704 to 712 and 714 for setting numbers and the like, an ID key 713, a clear key 715, a reset key 716, and the like. In addition, a display unit 720 with a touch panel formed on the top is provided, and soft keys can be created on the screen.

[0038] When the user presses the "Paper Selection" button 721 on the display unit 720 shown in FIG. 6(a), the CPU 101 transitions to the paper feed tray selection screen shown in FIG. 6(b) (S601). Then, the user selects which paper feed tray to feed sheets from. Here, the user selects the manual feed tray button 731 (S601, S602) and presses the "Next" button 732. When the button is pressed, the CPU 101 transitions to the sheet size setting screen shown in FIG. 6(c). Here, the user selects the A3 button 733 set in the manual feed tray (S603, S604) and presses the "Next" button 734. When the button 734 is pressed, the CPU 101 transitions to the sheet type setting screen shown in FIG. 6(d). Here, the user selects the type of sheet set in the sheet storage unit (S605, S606) and presses the "OK" button 735. When the button 735 is pressed, the screen transitions to the initial screen in Fig. 6(a), and the sheet registration process is completed. This completes the method for setting sheet information.

[0039] Next, the setting of the air blowing execution flag will be described. The air blowing target flag is determined based on the sheet type information stored in ROM 102 and the air blowing necessity determination table (FIG. 8) (S607). If the selected sheet type "requires air blowing," the air blowing target flag is set to ON (target) (S608). If air blowing "is not required," the air blowing target flag is set to OFF (not target) (S609). Next, it is determined whether the set paper size and paper type are the same as the paper size and paper type stored in RAM 103 (S610). If they are the same, the set sheet information and air blowing target flag are linked to the selected paper feed tray and saved in RAM 103 (S611). On the other hand, if they are different, the one-sheet placement counter is cleared to 0 (S612), the separation mode is set to ON (S613), and the set sheet information and air blowing target flag are linked to the selected paper feed tray and saved in RAM 103 (S611).

[0040] That is, the CPU 101 as the air handling necessity determination unit compares the set sheet type information with the air blowing necessity determination table, and sets whether to turn on the air blowing flag or turn off the air blowing flag. The air blowing target flag is used in the air blowing execution determination process described below. Note that the relationship between the sheet type and the air blowing necessity is not limited to the relationship shown here.

[0041] After setting the sheet information, pressing the start key 702 on the operation unit 700 starts the job and a sheet is fed from the selected sheet storage unit. Note that since the sheet information is saved in the RAM 103, it is not necessary to set it each time before starting a job. For example, if you have set plain A3 paper in the manual feed tray and executed a job, and then want to execute a job that feeds plain A3 paper from the manual feed tray again, all you need to do is press the start key 702.

[0042] <Air handling control setting> Next, the setting of whether or not to perform air handling control will be described with reference to the setting explanatory diagram of Fig. 9 and the flowchart of Fig. 10. The set whether or not to perform air handling control is used in the air blowing execution determination process described later.

[0043] The air handling setting is set from the operation unit 700, which serves as a feeding mode setting unit. It starts when the "Application Mode" button 722 shown in Fig. 6(a) is pressed. Then, when the "Air Handling" button 741 in Fig. 9(a) is pressed, the screen transitions to Fig. 9(b) (S401, Yes). When a button other than the "Air Handling" button is pressed (S401, No), the air handling setting is terminated in order to set a mode other than air handling. Note that when the "Close" button 742 is pressed, the air handling setting is terminated without setting any mode.

[0044] When the "Execute handling" button 743, which switches to the air feeding mode in Figure 9(b), is pressed (S402, Yes), the handling mode saved in RAM 103 is set to ON (S403), and the setting of the handling mode is completed. When the "Do not execute handling" button 744, which is a feeding mode that does not perform air handling, is pressed, the handling mode is set to OFF (S404), and the setting of the handling mode is completed. When the setting of the handling mode is completed, the screen transitions to the screen in Figure 6(a).

[0045] Although details will be explained later in the air blowing execution determination process, if the blowing mode is set to OFF, the air blowing process is not executed. In this way, by setting the blowing mode ON or OFF, the user can select to feed sheets without forcibly operating the blowing air. An example of a situation in which blowing air should not be forcibly operated is when quiet is required due to a meeting nearby the device.

[0046] <Air spray execution decision processing> The air blowing execution determination process for determining whether or not to perform air blowing in this embodiment will be described with reference to Figures 11 and 12. As described above, the air blowing execution determination process is executed at the start of sheet feeding control (S2 in the flowchart in Figure 5). The flow of the air blowing execution determination process will be described below.

[0047] First, in S101, the CPU 101 determines whether the acquired paper feed tray is for manual feeding and the sheet information selected from the RAM 103 is of a type that requires sheet sorting, and if so, proceeds to S102, otherwise proceeds to S108. Then, in S102, the CPU 101 checks the sorting mode stored in the RAM 103. If the sorting mode is ON, proceeds to S103, and if the sorting mode is OFF, proceeds to S108.

[0048] In S103, CPU 101 compares the one-sheet placement counter with a predetermined threshold value, and if the one-sheet placement counter is less than the threshold value, proceeds to S104, and if the one-sheet placement counter is equal to or greater than the threshold value, proceeds to S105. The one-sheet placement counter is a counter that indicates the number of times sheet feeding control has been executed consecutively with one sheet placed on manual tray 6. The procedure for adding the one-sheet placement counter will be described later. In S104, CPU 101 determines that air blowing will be executed, sets the air blowing execution flag to ON, and ends this flowchart.

[0049] On the other hand, if the one-sheet placement counter is greater than the threshold value, the process proceeds to S105, and the CPU 101 displays a message on the display unit 720, as shown in FIG. 11(b), prompting the user to decide whether to perform air blowing. In this embodiment, the message reads, "One sheet job is running in succession. Do you want to perform processing for the next one as well?" to notify the user. Then, "Execute" 751, "Execute only next job" 752, and "Remain stopped" 753 are displayed on the screen, allowing the user to select one of them.

[0050] 11B, the CPU 101 determines that the air blowing operation is necessary and proceeds to S104, where it sets the air blowing execution flag to ON, and ends this flowchart.

[0051] In S107, if the user selects "Stop next job only" 752 in FIG. 11(b), the CPU 101 determines that air blowing will not be executed only in this sheet feeding control, and proceeds to S108. Then, the air blowing execution flag is set to OFF, and this flowchart ends. In S107, if the user selects "Stop" 753 in FIG. 11(b), the CPU 101 determines that air blowing will not be executed after this sheet feeding control, and proceeds to S109. Then, in S109, the CPU 101 sets the handling mode to OFF, and then proceeds to S108, where the air blowing execution flag is set to OFF, and this flowchart ends.

[0052] In this embodiment, the threshold value (predetermined number of times) used in S103 is 2. That is, when the number of consecutive jobs in which sheet feeding control is executed with one sheet placed on the manual feed tray 6 is two or more, the message in FIG. 11B is displayed on the display unit 720. As described above, by displaying a message on the display unit and allowing the user to select whether to perform air blowing, unnecessary air blowing can be omitted and the execution time of sheet feeding control can be shortened. Note that, in the example shown, the message in FIG. 11B is displayed on the display unit 720 when two consecutive feeding jobs in the air feeding mode are executed, in which only one sheet has been fed and it is determined that there is no sheet before the next feeding operation. However, the message in FIG. 11B may also be displayed on the display unit 720 when three consecutive feeding jobs in the air feeding mode are executed, in which only one sheet has been fed and it is determined that there is no sheet before the next feeding operation.

[0053] <Placement determination process for placing one sheet> Next, the one-sheet placement determination process for determining whether or not the number of sheets placed on the manual feed tray 6 is one will be described with reference to the flowchart of FIG.

[0054] As described above, the single-sheet placement determination process is executed during a feeding job after a feeding operation in which a sheet is fed (S8 in FIG. 5). In S201, CPU 101 acquires the selected paper feed tray from RAM 103. If the acquired paper feed tray is "manual feed," the process proceeds to S202; if it is not "manual feed," the process ends this flowchart. In S202, CPU 101 increments the number of fed sheets stored in RAM 103. Note that the number of fed sheets is cleared to 0 when sheet feeding control starts (S1 in the flowchart in FIG. 5). In S203, CPU 101 determines whether or not paper is placed on manual tray 6 from manual tray sheet presence / absence detection sensor 401. If paper is present, it is determined that paper remains in manual tray 6 after feeding, so that not a single sheet is placed, and the process proceeds to S204. In S204, CPU 101 clears a single-sheet placement counter stored in RAM 103 to 0, and the process ends this flowchart.

[0055] On the other hand, if there is no paper in S203, the process proceeds to S205. In S205, CPU 101 checks the number of sheets fed stored in RAM 103. If the number of sheets fed is 2 or more, it is determined that the feeding operation of two or more sheets was performed without running out of paper, that is, not one sheet was loaded, and the process proceeds to S204, where the one-sheet loading counter is cleared to 0, and this flowchart ends. If the number of sheets fed is not 2 or more in S205, that is, if it is 1, it is determined that there was no paper after one sheet was fed, that is, one sheet was loaded, and the process proceeds to S206. In S206, CPU 101 increments the one-sheet loading counter stored in RAM 103, and this flowchart ends.

[0056] For example, assume that sheet feeding control is executed in the following order: one sheet is placed on manual feed tray 6 and fed, and then another sheet is placed on manual feed tray 6 and fed one sheet at a time. In this case, in Fig. 12, in the first feeding control, processing is executed in the order of S201 Yes, S202, S203 No, S205 No, and S206, and the one-sheet placement counter becomes 1. Then, in the second feeding control, processing is executed in the order of S201 Yes, S202, S203 No, S205 No, and S206, and the one-sheet placement counter becomes 2. Then, when the third feeding control, which is the subsequent job, is executed, the message shown in Fig. 11(b) is displayed on display unit 720.

[0057] However, suppose that in the third job, two sheets are loaded and two sheets are fed in the feeding control. In this case, when feeding the first of the two sheets, processing is executed in the order of S201 Yes, S202, S203 Yes, S204, and when feeding the second of the two sheets, processing is executed in the order of S201 Yes, S202, S203 No, S205 Yes, S204, and the one-sheet loading counter becomes 0. When feeding control is executed for the fourth time, the one-sheet loading counter is 0, so the message shown in FIG. 11(b) is not displayed on the display unit 720.

[0058] In this embodiment, the number of sheets fed is counted to determine whether one sheet is placed, but the number of sheets placed may be specified by the user. For example, when manual feed 731 is selected in Fig. 6(b), the screen transitions to Fig. 13, and the number of sheets placed is set using the numeric keys (760 to 769), the + button 771, and the - button 772, and then the "Next" button 773 is pressed to transition to Fig. 6(c).

[0059] <User authentication process> Next, authentication processing for a user who uses the image forming apparatus 201 will be described with reference to FIGS.

[0060] In S301, CPU 101 checks whether a user name has been entered. The user name is entered using the numeric keypad after pressing "User Name" button 781 shown in FIG. 15(a). Then, in S302, CPU 101 checks whether a password has been entered. The password is entered using the numeric keypad after pressing "Password" button 782 shown in FIG. 15(a).

[0061] In S303, the CPU 101 authenticates the user. When the "Login" button 783 shown in Fig. 15(a) is pressed, it checks whether the entered user name and password match the user name and password registered in advance and stored in the ROM 102. If the user name and password match, the process proceeds to S304; if they do not match, the process proceeds to S301.

[0062] In S304, the CPU 101 determines whether the logged-in user is the same as the user who logged in last time. The user name is compared with the login user name stored in ROM 102, and if the user name is the same as the user who logged in last time, the flow chart ends. If the user name is different from the user who logged in last time, the flow proceeds to S305. In S305, the CPU 101 clears the one-sheet placement counter stored in RAM 103 to 0, and in S306, the CPU 101 sets the handling mode stored in RAM 103 to ON. In S307, the CPU 101 updates the logged-in user name and ends the flow chart. When the flow chart ends, the screen shown in FIG. 15(b) is displayed. If the “Logout” button 784 shown in FIG. 15(b) is pressed or if no operation is performed for a predetermined time, the screen shown in FIG. 15(a) is displayed and the flow chart starts. In this embodiment, only numeric characters are used for the user name and password, but character strings such as alphabets may also be used.

[0063] This allows, when a different user operates the device, the air blowing operation to be performed on materials that require the air blowing operation, regardless of the work of the previous user.

[0064] In the embodiment described above, sheet feeding control in the manual feed unit 235 equipped with air blowing units 511A and 512A has been described. However, the present invention is not limited to this, and the sheet feeding control according to this embodiment may be performed in a sheet feeding unit 230 having a feed cassette 1 or a feed deck 500 having a deck unit 510 equipped with an air blowing unit. Furthermore, when the sheet feeding control according to this embodiment is performed in the sheet feeding unit 230, it may be performed at any stage in the vertical direction. In other words, the sheet support unit that supports the sheet stack may have any configuration.

[0065] In the above embodiment, the sheet feeding and separation unit is described as including a pickup roller for feeding sheets and a feed roller and a retard roller for separating overlapped sheets. However, the sheet feeding unit is not limited to this, and any configuration may be used for feeding sheets, such as a unit that feeds sheets by vacuum adsorbing them to a belt or the like.

[0066] In the above embodiment, the control unit 100 is described as being provided in the image forming apparatus 201. However, this is not limiting, and the control unit may be provided in the feeding deck 500. In other words, the control unit may be disposed in any device as long as it is electrically connected to the sheet feeding unit and the air blowing unit.

[0067] In the above embodiment, the manual pickup roller 501 that contacts the top sheet of a sheet stack and feeds the top sheet has been exemplified as the feeding unit that feeds sheets. However, the feeding unit may also be a feeding belt that uses air to adsorb a sheet and feeds the adsorbed sheet.

[0068] The present disclosure can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program, or by a circuit (e.g., ASIC) that realizes one or more functions. [Explanation of symbols]

[0069] 100 control unit (air handling necessity determination unit) 201B Image forming section 235 Manual feeding unit (sheet feeding device) 401 Sheet presence / absence detection sensor (detection part) 501 Pickup roller (feed roller) 511b, 512b Fan (blower) 514 Lifter plate (seat support part) 700 Operation section (sheet type setting section, feeding mode setting section) S seat

Claims

1. a seat support portion that supports the seat; a feeding unit that feeds the sheet supported by the sheet supporting unit; a blower that blows air toward an end of the sheet supported by the sheet support; a detection unit that detects whether or not a sheet is placed on the sheet support unit; a feeding mode setting unit that sets an air feeding mode in which the sheet is fed by the feeding unit after the air blowing unit blows air to separate the sheets, and a feeding mode in which the sheet is fed by the feeding unit without performing the air separation; a control unit that controls feeding in the mode set by the feeding mode setting unit, When the detection unit determines that there is no sheet after feeding one sheet placed on the sheet support unit and the feeding job in the air feeding mode has been executed a predetermined number of times in succession, the control unit prompts the user to select whether to execute feeding in the air feeding mode or the feeding mode before executing a feeding job subsequent to the feeding job, and feeds the sheet based on the selection. A sheet feeding device characterized by:

2. a sheet type setting unit for setting information on the type of sheet; an air separation necessity determination unit that determines whether the sheet type requires air separation based on the sheet type set by the sheet type setting unit.

2. The sheet feeding device according to claim 1, wherein the sheet feeding device is a sheet feeding device.

3. a counting unit that counts the absence of a sheet by the detection unit after feeding one sheet placed on the sheet support unit, When the counting means exceeds a predetermined value, the control unit prompts a user to select whether to perform feeding in the air feeding mode or the feeding mode, and feeds the sheet based on the selection.

2. The sheet feeding device according to claim 1, wherein the sheet feeding device is a sheet feeding device.

4. the control unit resets the count by the counting means when the detection unit determines that there is a sheet after the subsequent feeding job has fed one sheet placed on the sheet support unit.

4. The sheet feeding device according to claim 3, wherein the sheet feeding device is a sheet feeding device.

5. a sheet feeding device according to any one of claims 1 to 4; an image forming unit that forms an image on the sheet fed by the sheet feeding device; An image forming apparatus comprising:

Images