Feeding device and image forming apparatus

Abstract

To provide a feeding device and an image forming device that can effectively separate sheets using air regardless of their characteristics.SOLUTION: A feeding device includes a sheet stacking part that stacks sheets, a side fence that regulates the position of the sheets stacked on the sheet stacking part in the width direction, and air blowing means for blowing air to the leading end side in the feeding direction of the sheets stacked on the sheet stacking part. Multiple discharge ports 113a are provided at predetermined intervals in the feeding direction for discharging air flowed between the uppermost sheet and the second sheet on an auxiliary side fence that extends the side fence upstream in the feeding direction. Further, on the auxiliary side fences 113 are provided with shutter members 114 as opening / closing means to open and close the discharge ports, for every discharge port 113a.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] Conventionally, a feeding apparatus is known that includes a sheet stacking portion for stacking sheets, a side fence that regulates the position in the width direction of the sheets stacked on the sheet stacking portion, and an air blowing unit that blows air to the leading end side in the feeding direction of the sheets stacked on the sheet stacking portion.

[0003] Patent Document 1 describes the above feeding apparatus in which a plurality of discharge ports for discharging air that has been caused to flow between the uppermost sheet and the second sheet by the air blowing unit are provided in the side fence. These discharge ports are provided on the upstream side in the feeding direction relative to the portion of the side fence that faces the leading end side of the sheets.

Summary of Invention

Problem to be Solved by the Invention

[0004] However, depending on the characteristics of the sheets, there was a risk that separation failure would occur.

Means for Solving the Problem

[0005] In order to solve the above-described problem, the present invention provides a feeding apparatus comprising a sheet stacking portion for stacking sheets, a side fence that regulates the position in the width direction of the sheets stacked on the sheet stacking portion, and an air blowing unit that blows air to the leading end side in the feeding direction of the sheets stacked on the sheet stacking portion, wherein a discharge port for discharging the air that has been caused to flow between the uppermost sheet and the second sheet by the air blowing unit is provided on the upstream side in the feeding direction relative to the portion of the side fence that faces the leading end side of the sheets, and an opening and closing unit for opening and closing the discharge port is provided, Multiple discharge ports are provided at predetermined intervals in the feeding direction, and the opening and closing means are provided at each discharge port. These means acquire sheet information of the sheets loaded in the sheet loading section and open or close each opening and closing means based on the acquired sheet information. the feeding apparatus being characterized by that.

Effects of the Invention

[0006] According to the present invention, sheets can be effectively separated by air regardless of the sheet's characteristics. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic diagram of an image forming apparatus equipped with a feeding device according to this embodiment. [Figure 2] A schematic diagram illustrating the feeding and delivery system. [Figure 3] A perspective view showing the schematic configuration of one of the storage trays of the feeding device. [Figure 4] (a) is a perspective view showing the paper feeder without the expansion cartridge installed, and (b) is a perspective view showing the paper feeder with the expansion cartridge installed. [Figure 5] A schematic perspective view of a storage tray with an extended length in the sheet transport direction using an expansion cartridge. [Figure 6] This diagram illustrates the case where a conventional auxiliary side fence without an outlet is used. [Figure 7] A schematic perspective view showing the airflow when a long sheet, which is difficult to peel off and prone to floating, is set in a storage tray. [Figure 8] Although difficult to peel off, the buoyancy is shown in the schematic perspective view illustrating the airflow when a normal long sheet is set in the storage tray. [Figure 9] Perspective view of the storage tray with the auxiliary side fence of Modification 1 attached. [Figure 10] Perspective view of the storage tray with the auxiliary side fence of modification 2 attached. [Figure 11] A schematic perspective view of an embodiment in which an air outlet is provided in the end fence. [Modes for carrying out the invention]

[0008] The following describes one embodiment of a feeding device to which the present invention is applied. Figure 1 is a schematic diagram of an image forming apparatus 1 equipped with a feeding device according to this embodiment. As shown in Figure 1, the image forming apparatus 1 comprises an image forming apparatus body 100, which is an image forming means for forming an image on a sheet, and a feeding device 200 for feeding the sheet to the image forming apparatus body 100. The feeding device 200 is provided on the side of the image forming apparatus body 100.

[0009] There are no particular restrictions on the recording method of the image forming apparatus body 100, and any method such as electrophotography or inkjet can be adopted. In Figure 1, the right side of the image forming apparatus body 100 is provided with a sheet loading section from the feeding device 200. This sheet loading section is provided with an opening for receiving sheets and a transport means for transporting sheets.

[0010] Figure 2 is a schematic diagram of the feeding device 200. As shown in Figure 2, the feeding device 200 is equipped with two storage trays 10, one above the other. Each storage tray 10 is equipped with a sheet loading platform 11, which serves as a sheet loading area for stacking sheet bundles P. Each storage tray 10 can store, for example, up to about 2500 sheets.

[0011] Sheets include paper, coated paper, label paper, OHP sheets, films, and prepregs. Prepregs are mainly used as materials for laminates and multilayer printed circuit boards. For example, they are made by continuously impregnating a long base material such as glass cloth, paper, nonwoven fabric, or aramid cloth with a resin varnish mainly composed of thermosetting resins such as epoxy resin or polyimide resin, heating and drying it, and then cutting it to produce a sheet material.

[0012] Above each storage tray 10, a feeding unit 20 is positioned to separate and feed the sheets loaded onto the storage tray 10. This feeding unit 20 is equipped with a suction belt 21 and a suction device 23, which are means of transport.

[0013] The sheets stacked on the lower storage tray 10 are conveyed to the image forming apparatus main body 100 by the exit roller pair 80 through the lower conveyance path 82. The sheets stacked on the upper storage tray 10 are conveyed to the image forming apparatus main body 100 by the exit roller pair 80 through the upper conveyance path 81.

[0014] FIG. 3 is a perspective view illustrating a schematic configuration of one storage tray 10 of the feeding device 200. For clarity, the feeding unit 20 is illustrated shifted from its original arrangement position in the direction of arrow A in the drawing. The suction belt 21 of the feeding unit 20 serving as a feeding unit is stretched by two stretching rollers 22a and 22b. The suction belt 21 is provided with suction holes penetrating from the front surface side to the back surface side over the entire circumferential direction. A suction device 23 is provided inside the suction belt 21.

[0015] The suction device 23 is connected to a suction fan that sucks air through an air duct which is an air flow path, and generates a negative pressure downward by the suction device 23, so as to act to suck the sheet to the lower surface of the suction belt 21. The air sucked by the suction device 23 is referred to as suction air.

[0016] Further, the storage tray 10 includes a blower device 17 which is an air blowing unit that blows air onto the uppermost sheet of the sheet bundle P. This blower device 17 has a front blower device 12 and a side blower device 14.

[0017] The front blower device 12 blows air to the upper leading end (the end on the downstream side in the feeding direction) of the sheet bundle P. The front blower device 12 is provided with a floating nozzle that guides air in a direction to float the sheet bundle P, and a separation nozzle that guides and separates air between the uppermost floating sheet and the second floating sheet. Further, the front blower device 12 is provided with a floating blower 15 that sends air to the floating nozzle, and a separation blower 16 that sends air to the separation nozzle.

[0018] Of the nozzles, the air blown from the floating nozzles is referred to as floating air, and the air blown from the separating nozzles is referred to as separating air. The floating air is blown out in the direction of arrow a1 in Fig. 4 from a position facing the upper leading end (downstream end in the feeding direction) of the sheet bundle P, and is blown onto the upper leading end (downstream end in the feeding direction) of the sheet bundle P. The separating air is blown out in the direction of arrow a2 in Fig. 3 from a position facing the upper leading end (downstream end in the feeding direction) of the sheet bundle P, and is blown between the uppermost sheet attracted to the suction belt 21 and the floated second sheet.

[0019] The side air blower 14 is provided on a pair of side fences 13 that regulate the position of the sheet bundle in the width direction, and blows air toward the upper side surface of the sheet bundle P in the direction indicated by arrow b in the figure. The side air blower 14 is provided with side floating nozzles that guide air in the direction of separating and floating the sheet bundle P, and has a side blower 14a that feeds air to these nozzles. The air blown from the side floating nozzles in the direction indicated by arrow b in the figure is referred to as side air.

[0020] The side air is blown out from side air outlets 13a provided at positions of each side fence 13 facing the upper portion of the sheet bundle P, and is blown onto the upper side surface of the sheet bundle P. The sheets on the upper portion of the sheet bundle are floated by the air blown from the front air blower 12 and the side air outlets 13a of the pair of side fences 13.

[0021] Further, the storage tray 10 is provided with an end fence 25 that aligns the rear ends of the sheet bundle P stacked on the sheet stacking table 11 which is a sheet stacking portion. The sheet stacking table 11 is configured to be movable up and down in the direction of arrow B in the figure by an elevating device 19 which is a placing portion moving unit.

[0022] Next, the feeding operation will be described. When a command to start feeding is received from the higher-level controller of the image forming apparatus main unit 100, the lifting device 19 is driven to raise the sheet stacking platform 11. Then, when the sheet detection sensor detects the top surface of the sheet bundle, the drive of the lifting device 19 is stopped. Next, with the suction belt 21 stopped, the blower 17 is started to blow air and blowing control is started. Also, the suction device 23 is started to suction and suction control is started. By starting the blower 17 to blow air, floating air, separating air, and side air are blown from the floating outlet, separating outlet, and side air outlet 13a onto the front end of the top of the sheet bundle.

[0023] By blowing buoyancy air and side air, the leading edges of multiple sheets at the top of the sheet bundle float up, and the suction of the suction device 23 creates negative pressure below the suction belt 21, causing the floating top sheet to adhere to the suction belt 21. Once the top sheet is adhered to the suction belt 21, separation air is blown between the top sheet and the second sheet, separating the adhered top sheet from the second and subsequent sheets.

[0024] Next, the suction belt 21 is rotated to feed the top sheet. At this time, if the second and subsequent sheets float excessively or behave erratically and come into contact with the top sheet, there is a risk that they will be transported together with the top sheet. Therefore, when the feeding device 200 starts feeding the top sheet (when the suction belt 21 is rotated), it stops blowing the front levitation air and separation air. On the other hand, the side air continues to be blown even while the top sheet is being fed, to levitate the second sheet to be fed next.

[0025] Once a predetermined time has elapsed since the start of feeding (when the leading edge of the top sheet has been fed to the predetermined next process downstream of the suction belt (for example, the transport roller pair)), the suction by the suction device 23 is stopped, and the first sheet that is attached to the suction belt 21 is released. At the same time, the drive of the feeding motor is stopped, and the rotation of the suction belt 21 is stopped.

[0026] When there is another sheet to be fed, the blowing of front levitation air and separation air is resumed. Next, the suction device 23 resumes adsorption of the sheet onto the adsorption belt 21. Thereafter, the feeding process is carried out in the same manner as described above.

[0027] Furthermore, the feeding device 200 of this embodiment can accommodate long sheets longer than A3 portrait (420 mm) by attaching an expansion cartridge, which is an expansion unit, to extend the length of the storage tray 10 in the sheet transport direction.

[0028] Figure 4(a) is a perspective view showing the feeding device 200 without the expansion cartridge 210 installed, and Figure 4(b) is a perspective view showing the feeding device 200 with the expansion cartridge 210 installed. As shown in Figure 4(a), the housing 200a of the feeding device 200 is box-shaped and consists of a frame and a plurality of panels 201, 202, etc. that are attached to this frame. The storage tray 10 is configured to be retractable from the housing 200a towards the front in the figure, and the storage tray 10 can be pulled out from the housing 200a by the user grasping the handle portion 10a and pulling it towards the front in the figure. Pulling out the storage tray 10 makes it possible to load and unload sheet bundles P.

[0029] Panels 201 and 202 are attached to the upper and lower ends of the housing 200a on the upstream side in the transport direction. The upper panel 201 is detachably attached to the housing 200a with screws. By removing this panel 201, the expansion cartridge 210 is installed as shown in Figure 4(b).

[0030] Figure 5 is a schematic perspective view of the storage tray 10 with its length in the sheet transport direction extended by an expansion cartridge. When the length in the sheet transport direction is extended using the extension cartridge, an auxiliary side fence 113 is attached to the upstream end of each side fence 13 in the feeding direction, extending the side fences upstream in the feeding direction.

[0031] Multiple air outlets 113a are provided at predetermined intervals in the supply direction on the upper part of the auxiliary side fence 113 for discharging air. Furthermore, shutter members 114, which serve as opening and closing means for opening and closing the air outlets 113a, are provided on the side of the auxiliary side fence 113 opposite to the side facing the sheet (outside), corresponding to each air outlet 113a. Below each shutter member 114, a drive unit 115 is provided to drive the shutter member 114 vertically. Each drive unit 115 is connected to a shutter control unit 116.

[0032] A non-volatile storage unit 117, such as flash memory, is connected to the shutter control unit 116. The storage unit 117 stores a data table that associates sheet information (sheet thickness information, sheet type information such as coated paper or OHP) with shutter member opening and closing information. The shutter control unit 116 is capable of acquiring sheet information set in the storage tray 10. For example, when a user operates the operation panel of the image forming apparatus main unit 100 to input sheet information, the input sheet information is transmitted to the shutter control unit 116, which then acquires the sheet information. The shutter control unit 116 acquires opening and closing information for the shutter member 114 corresponding to the sheet set in the storage tray 10 from the acquired sheet information and the data table stored in the storage unit 117. Then, based on the acquired opening and closing information, the shutter control unit 116 controls each drive unit 115 to open and close the discharge port 113a using the shutter member 114. The sheet brand name may also be used as sheet information.

[0033] Each function performed by the shutter control unit 116 can be implemented by one or more processing circuits. Hereinafter, "processing circuit" as used herein includes processors programmed to execute each function by software, such as CPUs implemented by electronic circuits, as well as devices such as ASICs (Application Specific Integrated Circuits), DSPs (digital signal processors), FPGAs (field programmable gate arrays), and conventional circuit modules designed to perform the functions described above.

[0034] By attaching the auxiliary side fence 113 to the side fence 13 and extending the side fence in the feeding direction, it is possible to suppress the escape of air (mainly separated air) from the sheet width direction in the feeding direction area where the side fence 13 does not extend. This prevents air from reaching the rear end of the sheet and suppresses the occurrence of separation failures.

[0035] Figure 6 illustrates the case where a conventional auxiliary side fence without an outlet 113a is used. To avoid interference between the auxiliary side fence 113 and surrounding components, the height of the auxiliary side fence 113 is lower than the height of the side fence 13. Therefore, depending on the sheet, it may float above the auxiliary side fence 113, as shown in Figure 6. When the sheet floats above the auxiliary side fence 113 (hereinafter referred to as excessive floating), air escapes in the width direction of the sheet from the gap S between the top of the auxiliary side fence 113 and the portion of the sheet that has exceeded the auxiliary side fence 113 (see arrow D in the figure). In the case of sheets that are prone to floating, such as thin paper, the gap S between the top of the auxiliary side fence 113 and the portion of the sheet that has exceeded the auxiliary side fence 113 becomes larger, and there is a risk that too much air will escape from this gap S. As a result, the airflow volume at the rear end of the sheet decreases, and there is a risk that the air will not reach the rear end of the sheet, causing separation failure.

[0036] Therefore, it is conceivable to adjust the airflow to prevent the sheet from floating excessively (floating beyond the auxiliary side fence 113). However, depending on the characteristics of the sheet, such as a sheet that is difficult to peel and prone to floating, it may not be possible to suppress excessive floating by adjusting the airflow. For example, a sheet with strong adhesion and difficult to peel, such as coated paper, requires a certain amount of airflow to separate. On the other hand, if the coated paper is thin paper or has other characteristics that make it prone to floating, a strong airflow sufficient for separation will cause it to float significantly after peeling, resulting in excessive floating and the formation of a large gap S between the top of the auxiliary side fence 113 and the part of the sheet that exceeds the auxiliary side fence 113. As a result, as described above, too much air escapes from the gap S, reducing the airflow at the rear end of the sheet, preventing air from reaching the rear end of the sheet, and potentially causing separation failure.

[0037] Another measure to prevent excessive floating is to provide a floating-prevention section on the auxiliary side fence 113 to suppress the floating of the sheet. However, the height of the auxiliary side fence 113 is lower than the height of the side fence 13, and the height distance between the suction belt 21 and the floating-prevention section on the auxiliary side fence 113 becomes large. As a result, when the top sheet is fed by the suction belt 21, the top sheet may slide against the floating-prevention section, generating sliding resistance and potentially leading to feeding failure. In contrast, in this embodiment, an outlet is provided on the auxiliary side fence 113 to suppress excessive floating.

[0038] Figure 7 is a schematic perspective view showing the airflow when a long sheet of thin coated paper or other material that is difficult to peel and prone to floating is set in the storage tray 10. When a long sheet of thin coated paper or other material that is difficult to peel and prone to floating is placed in the storage tray 10, the shutter control unit 116 lowers all shutter members 114 and opens all discharge ports 113a. As a result, as shown by the arrows in the figure, the air pushing up the top sheet escapes appropriately from the discharge ports 113a, suppressing excessive floating (floating beyond the auxiliary side fence). By suppressing excessive floating in this way, too much air escape is prevented, and the air can flow to the rear end of the sheet. This suppresses the occurrence of separation failures.

[0039] Figure 8 is a schematic perspective view showing the airflow when a long sheet of material, such as coated paper of normal thickness, which is difficult to peel but has normal buoyancy properties, is set in the storage tray 10. For long sheets of coated paper of normal thickness that are difficult to peel but have normal buoyancy properties, opening all the outlets 113a may cause too much air to escape from the outlets 113a, resulting in insufficient airflow (air pressure) to lift the sheet at the rear end. This can lead to the air not reaching the rear end of the sheet and potentially causing separation failure. On the other hand, closing all the outlets 113a may cause excessive buoyancy on the upstream side of the auxiliary side fence in the supply direction.

[0040] Therefore, for long sheets that are difficult to peel but have normal buoyancy, for example, the two discharge ports 113a on the rear end of the sheet are closed by a shutter member 114 to prevent air from being discharged. This makes it possible to suppress both separation failures due to excessive buoyancy and separation failures due to excessive air leakage from the discharge ports 113a, even for long sheets that are difficult to separate but have normal buoyancy.

[0041] Furthermore, when a long sheet with poor release and lifting properties, such as thick coated paper, which is the most difficult to separate, is set in the storage tray 10, the shutter member 114 closes all the outlets 113a. This suppresses separation failures caused by air escaping from the outlets 113a. In addition, it becomes possible to reduce the airflow of the blower 17 (mainly the front blower 12), thereby suppressing increases in noise and power consumption. The above is just one example, and the size of the outlet 113a that is closed by the shutter member 114 can be determined as appropriate based on the sheet's characteristics such as peelability and buoyancy, and the set airflow rate.

[0042] In this embodiment, a shutter member 114 is provided, and the discharge port 113a is configured to be openable and closable, allowing air to be appropriately discharged from the discharge port 113a according to the sheet's characteristics, such as peelability and buoyancy. This makes it possible to suppress both separation failures due to excessive buoyancy and separation failures due to excessive air leakage from the discharge port 113a for a wide variety of sheets.

[0043] Furthermore, by combining the opening and closing control of the discharge port 113a by the shutter member 114 with the adjustment of the airflow rate, separation defects can be effectively suppressed for a wide variety of long sheets compared to cases where only the opening and closing control of the discharge port 113a or only the airflow rate adjustment is performed.

[0044] Furthermore, a narrower sheet allows air to escape more easily from the discharge port 113a compared to a wider sheet. Therefore, the discharge port 113a to be closed by the shutter member 114 may be determined based on three sheet pieces of information: thickness information, sheet type information, and sheet width size information.

[0045] Furthermore, as described above, a drive unit 115 is provided to automatically open and close the shutter member based on the sheet information entered by the user. However, the shutter member 114 may also be opened and closed manually. For example, a table showing the sheet information and the outlet to be closed could be included in the user manual or auxiliary side fence 113. The user could then determine which outlet to close from the sheet information to be set and the table in the user manual or auxiliary side fence 113, and manually move the shutter member 114 to open and close the outlet 113a.

[0046] [Example 1] Figure 9 is a perspective view of the storage tray 10 with the auxiliary side fence of Modification 1 attached. In this modified example 1, the auxiliary side fence 113 has a larger diameter towards the outlet 113a on the downstream side in the supply direction, and the amount of air that can be discharged towards the outlet 113a on the downstream side in the supply direction is increased. For example, in the case of long sheets of thin coated paper or other materials that are difficult to peel and prone to floating, the airflow is strong near the downstream end of the auxiliary side fence 113 in the feeding direction, which can cause the sheet to float significantly during separation, increasing the risk of excessive floating. Therefore, it is preferable to increase the diameter of the first outlet 113a in the airflow direction (opposite to the feeding direction) near the downstream end of the auxiliary side fence 113 in the feeding direction to allow for the discharge of more air. If the diameter of the second outlet 113a in the airflow direction is the same as that of the first outlet, too much air may escape, and the air may not reach the rear end of the sheet. On the other hand, if this second outlet is closed by the shutter member 114, excessive floating may occur. However, as shown in Figure 9, by making the diameter shorter for the outlets 113a on the upstream side in the feeding direction, and by reducing the amount of air that can be discharged for the outlets 113a on the upstream side in the feeding direction, the amount of air discharged from each outlet can be made appropriate compared to the case where the diameters of each outlet are the same.

[0047] Furthermore, the shutter member 114 may be used to change the opening area of ​​the outlet 113a, for example, by opening the upper half of the outlet 113a. This makes it possible to obtain the same effect as Modification 1 shown in Figure 9, even if the diameter of each outlet 113a is the same. In addition, compared to the configuration shown in Figure 9, the airflow rate of the air discharged from each outlet 113a can be controlled more precisely, making it possible to discharge air more appropriately.

[0048] Furthermore, for example, the spacing between the outlets 113a may be narrowed as you move downstream in the supply direction. With this configuration, the amount of air escaping from the outlets 113a can be increased downstream in the supply direction, and the amount of air escaping from the outlets 113a can be decreased upstream in the supply direction. Alternatively, the spacing between the discharge ports 113a may be narrowed as you move downstream in the supply direction, and the diameter of the discharge ports 113a may be increased as you move downstream in the supply direction.

[0049] Alternatively, the outlet 113a may be provided only in the area downstream of the central part of the auxiliary side fence 113 in the direction of air supply. On the other hand, providing the outlet 113a from the downstream to the upstream side in the direction of air supply of the auxiliary side fence 113 has the advantage of enabling more proper air discharge.

[0050] [Differentiation 2] Figure 10 is a perspective view of the storage tray 10 with the auxiliary side fence of Modification 2 attached. In this modified example 2, a lift detection sensor 118 is provided, which is a lift detection means for detecting the lifting of the uppermost sheet, and the shutter member 114 is controlled based on the detection result of this lift detection sensor 118. As shown in Figure 10, the buoyancy detection sensor 118 is located on the upper part of the downstream end of the auxiliary side fence 113 in the feeding direction.

[0051] A predetermined time has elapsed since the start of air blowing onto the sheet, and the floating position (height) of the uppermost sheet is detected by the floating detection sensor 118. The shutter control unit 116 controls the shutter members 114 based on the floating position detected by the floating detection sensor 118. For example, if multiple thresholds are set and the floating position detected by the floating detection sensor 118 is higher than the largest of the multiple thresholds, all shutter members 114 are moved downward and all discharge ports 113a are opened. Also, if the floating position detected by the floating detection sensor 118 is between the largest threshold and the second largest threshold, all shutter members except the upstreammost shutter member in the feeding direction are moved downward and all discharge ports except the upstreammost discharge port in the feeding direction are opened. Furthermore, for example, if the floating detection sensor 118 does not detect a sheet, all discharge ports 113a are kept blocked by the shutter members 114 and all discharge ports 113a remain closed.

[0052] In this modified example 2, air can be properly discharged from the outlet 113a, suppressing separation failures due to excessive buoyancy and separation failures due to excessive air leakage from the outlet 113a. Furthermore, the opening and closing of the shutter member 114 can be controlled without acquiring sheet information, eliminating the need for the user to input sheet information for the long sheets set in the storage tray 10.

[0053] In the above description, the auxiliary side fence 113 is provided with an outlet 113a and a shutter member 114. However, the outlet 113a and shutter member 114 may also be provided on the upstream side in the feeding direction of the portion of the side fence 13 that faces the front end of the sheet.

[0054] Figure 11 is a schematic perspective view of an embodiment in which an air outlet 125 is provided on the end fence 25. As shown in Figure 11, if the end fence 25 is wide, the air that reaches the rear end of the sheet is blocked by the end fence 25 and accumulates at the rear end of the sheet. This accumulated air may cause the rear end of the top sheet to float excessively (float above the auxiliary side fence). If the top sheet is fed by the suction belt 21 while the rear end of the top sheet is floating excessively, the rear end of the excessively floating sheet may get caught on a component placed on the upper surface of the storage tray 10. As a result, feeding failures or damage to the sheet may occur.

[0055] Therefore, as shown in Figure 11, by providing an outlet 125 on the end fence 25, air that has reached the rear end of the sheet can be discharged from the outlet 125. This suppresses excessive lifting of the rear end of the sheet, thereby reducing feeding problems and damage to the sheet.

[0056] Note that in Figure 11, the outlet 113a and shutter member of the auxiliary side fence 113 are not shown.

[0057] The above is just one example; each of the following embodiments produces its own unique effects. (Aspect 1) A sheet supply device comprising a sheet loading section such as a sheet loading platform 11 for loading sheets, a side fence for restricting the widthwise position of the sheets loaded on the sheet loading section, and an air blowing means such as a blower 17 for blowing air onto the leading edge of the sheets loaded on the sheet loading section in the supply direction, wherein an outlet 113a for discharging the air that has been flowed between the uppermost sheet and the second sheet by the air blowing means is provided upstream in the supply direction from the portion of the side fence facing the leading edge of the sheets, and the device is equipped with an opening and closing means such as a shutter member 114 for opening and closing the outlet 113a. The sheet loading section can accommodate a wide variety of sheets, and simply adjusting the airflow of the air blowing mechanism may not be sufficient to separate the sheets. For example, with thin coated paper, which adheres strongly to other sheets and is difficult to separate but easily floats, a certain amount of airflow is required to separate the top sheet from the second sheet. However, with this amount of airflow, the top sheet may float excessively beyond the side fence after separation, potentially creating a large gap between the top of the side fence and the excess portion of the sheet that has floated beyond the side fence. As a result, excess air from the air blowing mechanism, which is supplied between the top and second sheets, is discharged through this large gap. Consequently, the air may not flow to the rear end in the sheet's feeding direction, and the rear end of the top sheet may not be separated from the second sheet by air, potentially resulting in a separation failure. In Patent Document 1, an outlet for discharging air that has been blown between the uppermost sheet and the second sheet by an air blowing means is provided upstream in the feeding direction of the side fence from the portion of the side fence that faces the leading edge of the sheet in the feeding direction. By providing an outlet, the air is discharged appropriately from the outlet of the side fence, suppressing excessive floating of the sheet, which has characteristics of being difficult to peel off and prone to floating. This prevents the air from escaping from the gap between the top of the side fence and the portion of the sheet that extends beyond the side fence, and prevents the loss of airflow that is sufficient to separate the sheets at the rear end of the sheet. This suppresses poor separation of sheets, which have characteristics of being difficult to peel off and prone to floating. However, for example, if the sheets loaded in the sheet loading section are made of cardboard or other materials that are difficult to float, the top sheet may not be able to separate from the second sheet at the rear end, potentially resulting in a separation failure. This is because, in the case of sheets that are difficult to float, a large amount of energy is required to make them float. As a result, a stronger airflow is required compared to sheets that are difficult to peel and easy to float, in order to make the rear end of the top sheet float and separate it from the second sheet using the air flowing toward the rear end of the sheet that has been injected by the spraying means. However, as the air is discharged from the outlet, the airflow decreases, and there is a risk that it will become less than the amount of air needed to make the sheet float at the rear end. As a result, the rear end of the top sheet may not be able to be made to float and separate from the second sheet by the air from the spraying means, potentially resulting in a separation failure. In contrast, in embodiment 1, by providing an opening and closing mechanism such as a shutter member 114 that opens and closes the discharge port of the side fence, when a sheet with characteristics that make it difficult to float, such as cardboard, is set in the sheet loading section, the opening and closing mechanism closes the discharge port, preventing the air that has been blown between the top sheet and the second sheet by the blowing mechanism from being discharged from the discharge port. This suppresses a decrease in the airflow volume of the air that has been blown between the top sheet and the second sheet by the blowing mechanism. Therefore, the air that has been blown between the top sheet and the second sheet by the blowing mechanism lifts the top sheet all the way to its rear end, and poor separation of sheets that make it difficult to float can also be suppressed.

[0058] (Aspect 2) In embodiment 1, the side fence 13 is configured to be extendable upstream in the supply direction, and an auxiliary side fence 113 is provided with an outlet 113a when the side fence 13 is extended upstream in the supply direction. According to this, as described in the embodiment, the auxiliary side fence 113 can prevent air from escaping from the sheet width direction on the upstream side in the feeding direction. This prevents air from reaching the rear end of the sheet and suppresses the occurrence of separation failures. Furthermore, by providing an outlet 113a on the auxiliary side fence 113, the air that pushes up and lifts the sheet can be discharged from the outlet, preventing excessive lifting that would cause the sheet to float beyond the auxiliary side fence 113. This prevents air from escaping in the sheet width direction through the gap between the top of the auxiliary side fence 113 and the portion of the sheet that extends beyond the auxiliary side fence 113. As a result, the reduction in airflow is suppressed, allowing air to flow to the rear end of the sheet, and enabling good separation of the top sheet from the second sheet.

[0059] (Aspect 3) In embodiment 1 or 2, multiple discharge ports 113a are provided at predetermined intervals in the sheet feeding direction, and opening and closing means such as shutter members 114 are provided at each discharge port. According to this, compared to the case where there is only one outlet 113a, excess air can be discharged more effectively, and the air flow between the uppermost sheet and the second sheet can be made more appropriate compared to the case where there is only one outlet 113a.

[0060] (Aspect 4) In embodiment 3, the discharge port on the downstream side in the supply direction is larger than the discharge port on the upstream side in the supply direction. According to this, as explained using Figure 9, compared to the case where the diameter of each outlet is the same, the amount of air discharged from each outlet can be made appropriate, and both separation failures due to excessive buoyancy and separation failures due to excessive air leakage from the outlet on the upstream side in the supply direction can be suppressed.

[0061] (Aspect 5) In any of embodiments 1 to 4, an end fence 25 is provided to restrict the position of the rear end of the sheets loaded on the sheet loading section such as the sheet loading platform 11 in the sheet feeding direction, and an air outlet 125 is provided on the end fence 25 for discharging air. According to this, as explained using Figure 11, it is possible to suppress the accumulation of air that has reached the rear end of the sheet, and to suppress the excessive floating of the rear end of the top sheet.

[0062] (Aspect 6) In any of embodiments 1 to 5, sheet information (thickness information, type information, etc.) of sheets loaded on a sheet loading section such as a sheet loading platform 11 is acquired, and an opening / closing means such as a shutter member 114 is opened or closed based on the acquired sheet information. According to this, as described in the embodiment, air can be appropriately discharged from the discharge port 113a depending on the sheet's characteristics, such as its separability and buoyancy. This suppresses both poor separation due to excessive buoyancy and poor separation due to excessive air leakage from the discharge port 113a, enabling efficient sheet feeding.

[0063] (Aspect 7) In any of embodiments 1 to 5, the system includes a lift detection means such as a lift detection sensor 118 that detects the lifting of the uppermost sheet loaded on a sheet loading section such as a sheet loading platform 11 by air, and opens or closes an opening / closing means such as a shutter member 114 based on the detection result of the lift detection means. According to this, as explained in Modification 2, air can be properly discharged from the discharge port 113a, suppressing both separation failures due to excessive buoyancy and separation failures due to excessive air leakage from the discharge port 113a, and enabling the sheet to be fed smoothly.

[0064] (Pattern 8) In an image forming apparatus for forming an image on a sheet fed by a feeding device, any of the feeding devices from embodiments 1 to 7 was used as the feeding device. This method can suppress problems with the feeding of the sheet. [Explanation of symbols]

[0065] 1: Image forming apparatus 10: Storage tray 11: Sheet loading platform 12: Front ventilation system 13: Side fence 14: Side ventilation system 14a: Side blower 15: Floating Blower 16: Separation blower 17: Blower 20: Supply Unit 21: Suction belt 23:Suction device 25: End fence 100: Image forming apparatus main unit 113: Auxiliary side fence 113a: Outlet 114: Shutter component 115: Drive unit 116: Shutter control unit 117: Storage section 118: Floating detection sensor 125: Outlet 200:Feeding device 210: Expansion Cartridge P: Sheet bundle [Prior art documents] [Patent Documents]

[0066] [Patent Document 1] Japanese Patent Publication No. 2009-280345

Claims

1. A seat loading section for loading seats, Side fences that restrict the widthwise position of the sheets loaded in the sheet loading section, A feeding device comprising an air blowing means for blowing air onto the leading edge in the feeding direction of the sheets loaded in the sheet loading section, An outlet for discharging the air that has been blown between the uppermost sheet and the second sheet by the air blowing means is provided upstream in the supply direction from the portion of the side fence facing the front end of the sheet. The outlet is equipped with an opening and closing mechanism, Multiple discharge ports are provided at predetermined intervals in the supply direction. The opening and closing means is provided at each outlet, A feeding device characterized by acquiring sheet information of sheets loaded in the sheet loading section and opening and closing each opening / closing means based on the acquired sheet information.

2. In the feeding device according to claim 1, The aforementioned side fence is configured to be extendable upstream in the feeding direction, A feeding device characterized in that, when the side fence is extended upstream in the feeding direction, the discharge port is provided on the auxiliary side fence that is attached.

3. In the feeding device according to Claim 1, A feeding device characterized in that the discharge port on the downstream side in the feeding direction is larger than the discharge port on the upstream side in the feeding direction.

4. In the feeding device according to claim 1, The sheet loading section is equipped with an end fence that restricts the position of the rear end of the sheet loaded in the sheet feeding direction, A feeding device characterized by having an air outlet provided in the end fence.

5. In the feeding device according to Claim 1, It has a lift detection means for detecting the lifting of the uppermost sheet loaded in the sheet loading section by the air, A feeding device characterized by opening and closing the opening / closing means based on the detection result of the floating detection means.

6. In an image forming apparatus that forms an image on a sheet fed by a feeding device, An image forming apparatus characterized in that the feeding device described in claim 1 is used as the feeding device.

Images