JP5440301B2 - Image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus.

  In a paper feeding device in an image forming apparatus, various methods are used for separating and transporting the uppermost paper in a paper feeding tray containing paper. As one of the methods, there is a method of sucking (air suction) the uppermost sheet of the paper feed tray and separating and transporting the paper. A paper feed device using air suction is described in, for example, Patent Document 1. .

  FIG. 12 is a diagram illustrating an example of a conventional paper feeding device that uses a method of conveying paper while sucking and separating paper. As shown in FIG. 12, a paper feed unit 510 is installed in the vicinity of the leading end of the paper S stored in the paper feed tray 500 in the feed direction. The paper base 501 on which the paper S is stacked moves up and down so that the top surface of the paper S has a constant height regardless of the paper stacking amount.

  The paper feed unit 510 has a paper feed belt 513 that rotates by winding a large roller 511 connected to a drive source and two small rollers 512. The sheet feeding belt 513 has a large number of small-diameter through holes. A suction duct 514 that communicates with a suction fan is disposed inside the paper feed belt 513, and the paper S is sucked through the paper feed belt 513, and the paper S is conveyed by the paper feed belt 513. When the sheet feeding belt 513 rotates while sucking the sheet S, the uppermost sheet S of the sheet bundle stored in the sheet feeding tray 500 advances in the direction of the arrow W in FIG. It is sent.

JP 2006-327778 A

  By the way, a paper feeding apparatus using air suction separates and conveys paper by air suction with a paper feeding belt. When a series of paper feeding operations is completed, the suction fan is turned off, but the suction fan blades are turned off. Will continue to rotate by inertia for some time. For this reason, even after the completion of the paper feeding operation, the paper stored in the paper feeding tray may be attracted to the paper feeding belt. There is a risk that the paper adsorbed by the paper belt may be caught in the paper feed tray and the paper feed belt may come off.

  Therefore, in order to prevent such a problem, an adsorption detection sensor for detecting the adsorption of the paper on the paper feed belt is provided in the paper feeding device, and while the paper adsorption on the paper feed belt is detected, The movement is restricted (locked) so that the paper feeding tray cannot be pulled out of the paper feeding device.

  However, after the suction fan is turned off, the paper may be attracted to the paper feed belt for several minutes. If the paper feed tray cannot be pulled out while the paper is attracted to the paper feed belt, The operation time of the image forming apparatus may be lost.

It is an object of the present invention, it is possible to prevent the paper after the paper feeding operation is completed continue to adsorb to the paper feeding belt, to provide an inhibiting image forming apparatus uptime loss of the image forming apparatus.

In order to achieve the above object, an image forming apparatus according to the present invention includes:
A paper tray for storing paper,
A suction duct through which air sucked from the paper feed tray by a suction fan passes;
A conveyor belt installed outside the suction port in the suction duct, and transports the paper in the paper feed tray sucked by the suction fan to the outside of the paper feed tray;
An image forming unit that forms an image on the paper conveyed by the conveyance belt;
A separating portion that separates the suction port and the conveyor belt;
As for spacing the conveyor belt and the suction port, possess a control unit for controlling at least the spacing portion,
A plurality of the conveyor belts are installed in the width direction orthogonal to the sheet conveyance direction,
When separating the plurality of conveyor belts from the suction port, separating the plurality of conveyor belts from the suction port at the same timing, and returning the separated plurality of conveyor belts to their original positions, The control unit controls the separation unit so that the plurality of transport belts are returned to their original positions at different timings .

According to the image forming apparatus of the present invention, it is possible to prevent the sheet from being continuously attracted to the sheet feeding belt after the sheet feeding operation is completed, and to suppress the operation time loss of the image forming apparatus.

1 is an overall configuration diagram of an image forming apparatus according to the present invention. It is a perspective view which shows the outline of the air suction paper feeding mechanism in a paper feeding apparatus. It is principal part sectional drawing of an air suction paper feeding mechanism and its periphery structure. It is sectional drawing in XX of FIG. It is explanatory drawing which shows the structure where a conveyance belt etc. rotate centering on an axis | shaft. It is explanatory drawing which shows the structure where a conveyance belt etc. rotate centering on an axis | shaft. It is explanatory drawing which shows the state which a conveyance belt spaces apart with respect to a suction opening. It is explanatory drawing which shows the state which a conveyance belt spaces apart with respect to a suction opening. It is sectional drawing of the predetermined position which shows the relationship between the suction duct and the conveyance belt seen from the large diameter roller side. It is sectional drawing of the predetermined position which shows the relationship between the suction duct and the conveyance belt seen from the large diameter roller side. It is sectional drawing of the predetermined position which shows the relationship between the suction duct and the conveyance belt seen from the large diameter roller side. It is a figure which shows the example of the conventional paper feeding apparatus using the method of conveying a paper while attracting | sucking and isolate | separating.

[Outline of image forming apparatus]
FIG. 1 is an overall configuration diagram of an image forming apparatus A according to the present invention.

  The image forming apparatus A mainly includes a paper feeding device LT and an image forming device main body B, and forms an image on a sheet stored in the paper feeding device LT or the like.

  The sheet feeding device LT has three stages of sheet feeding trays T1, T2, and T3 connected to the sheet feeding path of the image forming apparatus main body B. Each sheet feeding tray stores a large amount of sheets. . An air suction paper feed mechanism AF is installed above each paper feed tray, and the paper in each paper feed tray is conveyed to the image forming apparatus main body B by the air suction paper feed mechanism AF.

  The image forming apparatus main body B has an automatic document feeder ADF and an image reading unit SC in the upper part, and an image forming part IF in the lower part. The image forming apparatus main body B is also provided with paper supply trays 1a and 1b for storing paper. The paper supply trays T1, T2 and T3 of the paper supply apparatus LT or the paper supply trays 1a and 1b of the image forming apparatus main body B are installed. An image is formed in the image forming unit IF on the sheet conveyed from the printer.

  In the image forming unit IF, the toner image formed on the photoconductor 2 by the electrophotographic process is transferred onto the paper, and the toner image transferred onto the paper is fixed by the fixing device 3. The sheet after fixing is discharged from the paper discharge port by the paper discharge roller 4. When images are formed on both sides of the paper, the paper discharged from the fixing device 3 is conveyed downward before the paper discharge roller 4, is returned to the transfer position again via the double-sided conveyance path 5, and an image is formed on the back surface. The

  The control unit SG controls the operation of each unit of the image forming apparatus A. Specifically, the control unit SG controls the image forming operation in the image forming unit IF, the paper feeding operation in the paper feeding device LT, and the like.

[Outline of air suction feeding mechanism]
FIG. 2 is a perspective view schematically showing an air suction paper feeding mechanism in the paper feeding device LT.

  In FIG. 2, the sheets are stacked on the sheet stacking table 10 and conveyed one by one in the direction of the arrow a. The paper stacking base 10 is always lifted so that the position of the uppermost paper is constant, and is lowered when the paper is replenished.

  A front end regulating member 11 is installed in front of the paper stacking base 10, and a separation air blower 12 is installed downstream of the front end regulating member 11 in the paper transport direction. Floating air blowing units 13 and 14 are installed on both sides of the paper stacking base 10, and the inside of the floating air blowing units 13 and 14 regulates the side surface of the sheet. Further, a rear end regulating member 15 is installed behind the paper stacking base 10.

  The blower fans 12a and 13a are installed in the separated air blower 12 and the floating air blowers 13 and 14, respectively, and air is blown from the blowers 12b, 13b, and 14b.

  An air suction paper feeding mechanism AF (see FIG. 1) is installed above the paper stacking base 10, and in FIG. 2, the conveying belts 20a, 20b, 20c, and 20d, which are part of the air suction paper feeding mechanism AF, are indicated by arrows. Are shifted to the positions shown in FIG. A suction duct 21 is installed inside the conveyor belts 20a, 20b, 20c, and 20d.

  The sheets stacked on the sheet stacking table 10 are sucked by the suction duct 21. At this time, air from the floating air blowing sections 13 and 14 blows from both sides to the sheet side surface, Three sheets are floated, and the air from the separation air blower 12 separates one sheet from the suction duct 21 and the remaining sheets, and one sheet is reliably sucked by the suction duct 21. Acts like

  3 is a cross-sectional view of a main part of the air suction paper feeding mechanism AF and its peripheral configuration, and FIG. 4 is a cross-sectional view taken along the line XX of FIG. The structure of the air suction paper feeding mechanism AF will be described in detail with reference to FIGS.

  The air suction paper feed mechanism AF is located above the paper stacking base 10 and is provided in front of the suction duct 21, the large-diameter roller 22 provided behind the suction duct 21 in the paper conveyance direction, and in front of the suction duct 21 in the paper conveyance direction. The small-diameter rollers 23a and 23b and the four conveying belts 20a, 20b, 20c, and 20d wound around the large-diameter roller 22 and the like are provided.

  The suction duct 21 has a portion corresponding to the four transport belts 20a, 20b, 20c, and 20d and a portion extending to the back side of the paper feeding device LT, and the inside of the suction duct 21 is divided into two by a partition wall 32. Has been. In the suction duct 21, a plurality of suction ports 31 are provided on the lower surface side of portions corresponding to the transport belts 20 a, 20 b, 20 c, and 20 d, and a suction fan 33 is installed on the back side of the suction duct 21. . The suction duct 21 is held by a holding plate 34 located on the upper side, and the holding plate 34 is connected to the housing of the paper feeding device LT via a slide rail 35.

  The large-diameter roller 22 and the small-diameter rollers 23a and 23b are formed in a drum shape so that the wound conveyor belts 20a, 20b, 20c and 20d are not laterally displaced (conveyor belts are provided with a flange at the end of each roller). 20a, 20b, 20c, 20d may be prevented from being laterally displaced). A gear 25 is provided on the back side of the shaft 24 of the large-diameter roller 22, and the gear 25 is connected to a motor M 1 with a clutch via a relay gear 26. Detection flaps 27 of suction sensors are provided at two positions between the large-diameter rollers 22, and when the paper is sucked into the air, the detection flaps 27 are pushed in to detect the suction of the paper.

  The conveying belts 20a, 20b, 20c, and 20d that convey the air-sucked paper are perforated belts having a large number of holes. When the suction fan 33 is turned on, the uppermost sheet on the sheet stacking table 10 is sucked and floats upward, the sheet is adsorbed to the transport belts 20a, 20b, 20c, and 20d, and the transport belts 20a, 20b, 20c, and 20d. Thus, the sheet is conveyed to the image forming apparatus main body B. The conveyor belts 20a, 20b, 20c, and 20d are installed in the width direction orthogonal to the sheet conveyance direction.

  A motor M2 is fixed to the housing of the paper feeding device LT, and a pinion gear 41 provided on the shaft of the motor M2 is engaged with a rack 42 fixed to a side portion of the suction duct 21. Accordingly, the air suction paper feeding mechanism AF including the transport belts 20a, 20b, 20c, 20d, the suction duct 21 and the like can be moved in the transport lateral direction by the slide rail 35 as a whole.

  In FIG. 3, the separation air blower 12 is positioned below the small diameter roller 23 b of the air suction paper feeding mechanism AF. A partition wall 52 and a switching plate 53 are provided inside the air blowing opening 51 of the separation air blowing unit 12, and the switching plate 53 is displaced between a solid line position and a one-dot chain line position, thereby changing the blowing position of the separation air. At the time of starting the suction of the paper, the switching plate 53 blows air from the lower ventilation opening at the one-dot chain line position, and when several sheets are lifted by the floating air and sucked by the air, the switching plate 53 Displacement to the solid line position blows air from the upper air blowing opening to reliably separate the paper.

[Separation of paper adsorbed on the conveyor belt]
As described with reference to FIGS. 3 and 4, in the air suction paper feeding mechanism AF, the suction belt 33 sucks the paper onto the transport belts 20 a, 20 b, 20 c, and 20 d so that the paper feeding device LT performs the image forming apparatus. The paper is transported to the main body B (paper feeding operation). When the image forming job in the image forming apparatus A is completed and a series of paper feeding operations by the air suction paper feeding mechanism AF is completed, the suction fan 33 is turned off. It continues to rotate with time and inertia. As a result, if no measures are taken, the sheet is sucked by the suction fan 33 and adsorbed to the transport belt B while the suction fan 33 rotates by inertia even after the paper feeding operation is completed. Therefore, in the image forming apparatus A according to the present embodiment, the suction port 31 and the transport belt when the job execution is completed to prevent the sheet from being attracted to the transport belts 20a, 20b, 20c, and 20d after the paper feeding operation is completed. It operates so as to separate 20a, 20b, 20c, and 20d. Hereinafter, this point will be described.

  5 and 6 are explanatory views showing a structure in which the conveyor belt 20a and the like rotate around the shaft 23a1.

  Although not shown in FIGS. 3 and 4, a solenoid (spacer) 28 is installed below the shaft 24 of the large-diameter roller 22 as shown in FIGS. 5 and 6, and the pin 28 a of the solenoid 28 is connected to the shaft 28. The shaft 24 is supported in contact with the shaft 24. The solenoid 28 is controlled by the control unit SG (see FIG. 1) in the image forming apparatus main body B described above, and the pin 28A is movable in the vertical direction.

  The conveyor belts 20a, 20b, 20c, 20d, the large-diameter roller 22, the small-diameter roller 23b, and the like can be rotated integrally with the shaft 23a1 of the small-diameter roller 23a as a fulcrum, and the pin 28A of the solenoid 28 can be moved up and down. Following this, the conveyor belts 20a, 20b, 20c, 20d, the large-diameter roller 22, the small-diameter roller 23b, and the like rotate integrally.

  When the paper is fed from the paper feeding device LT by the air suction paper feeding mechanism AF, the pin 28a is in the state shown in FIG. 5, and the shaft 24 is supported by the pin 28a and the conveying belts 20a, 20b, 20c, 20d. Etc. are positions shown in FIG.

  When the control unit SG controls the solenoid 28 and the pin 28a moves in the direction of the arrow (downward) in FIG. 5, the conveyor belts 20a, 20b, 20c, 20d, etc. rotate integrally with the shaft 23a1 as a fulcrum by their own weight, As shown in FIG. 6, the conveyor belts 20a, 20b, 20c, and 20d are inclined. When the control unit SG controls the solenoid 28 and the pin 28a moves in the direction of the arrow (upward) in FIG. 6, the pin 28a pushes up the shaft 24 so that the transport belts 20a, 20b, 20c, 20d and the like rotate integrally. To return to the original position shown in FIG.

  The movement of the conveyor belts 20a, 20b, 20c, 20d, the large-diameter roller 22, the small-diameter roller 23b, and the like integrally following the vertical movement of the pin 28A of the solenoid 28 is the conveyance belt 20a with respect to the suction port 31. , 20b, 20c, and 20 are performed to separate each other. Next, the operation of separating the conveyor belts 20a, 20b, 20c, 20 from the suction port 31 will be described with reference to FIGS.

  7 and 8 are explanatory views showing a state in which the transport belts 20a, 20b, 20c, and 20d are separated from the suction port 31. FIG. The positions of the conveyor belts 20a, 20b, 20c, 20d, the large diameter roller 22, the small diameter roller 23b, and the like match in FIGS. 5 and 7, and match in FIGS. 6 and 8.

  As described above, when the paper is fed from the paper feeding device LT by the air suction paper feeding mechanism AF, the pin 28a is in the state shown in FIG. 5, and in this state, as shown in FIG. There are no gaps between the conveyor belts 20a, 20b, 20c, and 20d. Accordingly, when the suction fan 33 is turned on and the suction duct 21 has a negative pressure, the paper S sucked by the suction fan 33 is attracted to the transport belts 20a, 20b, 20c, and 20d, and the paper S is transported by the transport belts 20a, 20b, It is conveyed by 20c and 20d.

  When the job execution in the image forming apparatus A is completed and a series of paper feeding operations are completed, the suction fan 33 is turned off and the solenoid 28 is controlled by the control unit SG, so that the pin 28a moves downward as shown in FIG. To do. As a result, the conveyor belts 20a, 20b, 20c, and 20d are inclined as shown in FIG. 8, and the conveyor belts 20a, 20b, 20c, and 20d are separated from the suction port 31 as shown in FIG. SP occurs. In this case, since the negative pressure in the suction duct 21 is released and the suction force is reduced even if the suction fan 33 rotates due to inertia, the paper S is separated from the transport belts 20a, 20b, 20c, and 20d. Falls down.

  As described above, when the job is finished, the solenoid 28 is used to separate the suction port 31 from the transport belts 20a, 20b, 20c, and 20d. It is possible to prevent the adsorption to 20b, 20c, and 20d. As a result, it is possible to suppress an operation time loss of the image forming apparatus A, for example, a paper replenishment operation can be performed immediately on the paper feed tray T1 or the like when the job execution is completed.

  Note that in the image forming apparatus A of the present embodiment, the suction duct 21, the suction fan 33, and the like have a larger structure than the transport belts 20a, 20b, 20c, and 20d, so the position of the suction port 31 is fixed. The transport belts 20a, 20b, 20c, and 20d that are easy to move are separated from each other. However, any structure may be used as long as the suction port 31 and the transport belts 20a, 20b, 20c, and 20d are separated from each other. . For example, unlike the image forming apparatus A of the present embodiment, the positions of the conveying belts 20a, 20b, 20c, and 20d are fixed, and the suction port 31 is separated from the conveying belts 20a, 20b, 20c, and 20d. Also good. Further, the conveyor belts 20a, 20b, 20c, and 20d may be pushed outward from the inside by an actuator or the like to separate the conveyor belts 20a, 20b, 20c, and 20d from the suction port 31, or The conveying belts 20a, 20b, 20c, and 20d may be separated from the suction port 31 by bringing the small-diameter rollers 23a and 23b close to each other and reducing the tension of the conveying belts 20a, 20b, 20c, and 20d.

[Modification of returning the conveyor belt to its original position]
There are four transport belts for transporting paper from the paper feeding device LT. In the image forming apparatus A in the present embodiment, when the transport belts 20a, 20b, 20c, and 20d are separated from the suction port 31, all four belts have the same timing. The four belts are also controlled so as to be returned at the same timing when they are separated by (1) and the conveying belt is returned to the original position. As a modified example of the operation of the transport belt, when the transport belt is separated from the suction port 31, all four belts are separated at the same timing, and when returning to the original position, an operation of returning at a different timing can be considered. Hereinafter, the modification will be described with reference to FIGS.

  9 to 11 are cross-sectional views at predetermined positions showing the relationship between the suction duct 21 and the conveyor belts 20a, 20b, 20c, and 20d as viewed from the large-diameter roller 22 side.

  Although the detailed structure is not shown in FIGS. 9 to 11, in the modification shown in FIGS. 9 to 11, the large-diameter roller 22, the shaft 24, and the solenoid 28 that support the respective conveyor belts 20 a, 20 b, 20 c, and 20 d are individually provided. The conveyor belts 20a, 20b, 20c, and 20d are rotated independently by the control unit SG (see FIG. 1).

  When the paper is fed from the paper feeding device LT by the air suction paper feeding mechanism AF, as shown in FIG. 9, the transport belts 20a, 20b, 20c, and 20d are in contact with the suction port 31, and the suction fan 33 is turned on. When the pressure inside the suction duct 21 becomes negative, the paper S sucked by the suction fan 33 is attracted to the transport belts 20a, 20b, 20c, and 20d, and the paper S is transported by the transport belts 20a, 20b, 20c, and 20d.

  When the paper feeding operation is completed, the conveying belts 20a, 20b, 20c, and 20d are connected to the suction port 31 as shown in FIG. Separate. When the transport belts 20a, 20b, 20c, and 20d are separated from the suction port 31, they are separated at the same timing (shown in the separated state in FIG. 10).

  If the conveyor belts 20a, 20b, 20c, and 20d are separated from the suction port 31, the negative pressure in the suction duct 21 is released and the suction force decreases even if the suction fan 33 rotates due to inertia. The paper S is separated from 20a, 20b, 20c, and 20d, and the paper S falls downward. However, in some cases, the sheet S may continue to adhere to the transport belts 20a, 20b, 20c, and 20d due to electrostatic force or the like.

  Therefore, in order to reliably separate the paper S from the transport belts 20a, 20b, 20c, and 20d, when the transport belts 20a, 20b, 20c, and 20d are returned to their original positions, they are returned at different timings. For example, as shown in FIG. 11, the belts are returned to their original positions in the order of the conveyor belt 20a → the conveyor belt 20b → the conveyor belt 20c → the conveyor belt 20d. In this way, when the transport belts 20a, 20b, 20c, and 20d are returned to their original positions, the sheet S can be peeled off from the transport belts 20a, 20b, 20c, and 20d by returning at different timings. The sheet S can be reliably separated from the belts 20a, 20b, 20c, and 20d, which is effective.

  The transport belts 20a, 20b, 20c, and 20d may be returned to their original positions at different timings. For example, the transport belt 20d → the transport belt 20c → the transport in order from the left transport belt 20d shown in FIG. You may make it return to the original position in order of belt 20b-> conveyance belt 20a.

  As mentioned above, although this invention was demonstrated by embodiment shown in FIGS. 1-12, this invention is not limited to the said embodiment, Even if there exists a change and addition in the range which does not deviate from the summary of this invention, Included in the invention.

A Image forming apparatus AF Air suction paper feeding mechanism B Image forming apparatus main body IF Image forming unit LT Paper feeding apparatus T1, T2, T3 Paper feeding tray 10 Paper stacking base 20a, 20b, 20c, 20d Conveying belt 21 Suction duct 22 Large diameter Roller 23a, 23b Small diameter roller 24 Shaft 28 Solenoid 28a Pin 31 Suction port 33 Suction fan

Claims (2)

A paper tray for storing paper,
A suction duct through which air sucked from the paper feed tray by a suction fan passes;
A conveyor belt installed outside the suction port in the suction duct, and transports the paper in the paper feed tray sucked by the suction fan to the outside of the paper feed tray;
An image forming unit that forms an image on the paper conveyed by the conveyance belt;
A separating portion that separates the suction port and the conveyor belt;
As for spacing the conveyor belt and the suction port, possess a control unit for controlling at least the spacing portion,
A plurality of the conveyor belts are installed in the width direction orthogonal to the sheet conveyance direction,
When separating the plurality of conveyor belts from the suction port, separating the plurality of conveyor belts from the suction port at the same timing, and returning the separated plurality of conveyor belts to their original positions, The image forming apparatus in which the control unit controls the separation unit so that the plurality of transport belts are returned to their original positions at different timings .   The image forming apparatus according to claim 1, wherein the separation unit separates the conveyance belt from the suction port.

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