Sheet feeding device equipped with a heating unit

Abstract

A sheet feeder (1) is provided, comprising a storage surface (11) for a stack of sheets (5), a blower arrangement comprising a plurality of side blower units (21) and a front blower unit (22), and at least one fan (23) configured to provide one or more air flows (3) to each of the side blower units and the front blower unit. The side blower units and the front blower unit are configured to direct the one or more air flows towards an upper region (12) of the sheet feeder to float a plurality of upper sheets (5a) of the stack of sheets. The sheet feeder further comprises a vacuum belt feeder (30) configured to grip and feed a topmost sheet (5b) of the plurality of floated sheets. The blower apparatus further comprises a heating unit (40) disposed between a first fan (23) of the at least one fan and the front blower unit and configured to heat one or more air flows supplied by the first fan to the front blower unit.

Description

[Technical field]

[0001] The present disclosure relates to a sheet feeding apparatus for the printing industry, for example a sheet feeding apparatus for a printer, copier, or sorter. [Background technology]

[0002] Sheet feeders are commonly incorporated into printers or copiers into which a number of sheets are manually loaded for automatic feeding of the sheets, one at a time, for a subsequent operation on the sheets, such as printing or sorting.

[0003] An example of a prior art sheet feeding apparatus by the applicant is described in Swedish patent specification published under SE 540 166 C2 which discloses a sheet feeding apparatus comprising a storage surface for a stack of sheets of paper adapted to be moved between a lower position and an upper position, a vacuum feeder for feeding the sheets of paper from their positions on the storage surface, and a blower arrangement adapted to provide a curtain of air separating the topmost sheet of paper from the remainder of the stack of sheets of paper.

[0004] A challenge for sheet feeders is to handle sheets of various materials and qualities while minimizing or eliminating problems associated with double-feeds, sheet jams, or manual setup and adjustments to operate the sheet feeder with different sheet sizes and qualities. It is therefore important to reduce problems associated with double-feeds, sheet jams, or manual setup and adjustments to operate the sheet feeder with different sheet sizes and qualities. Summary of the Invention

[0005] It is therefore an object to provide a sheet feeding apparatus that reduces problems associated with double-feeding, sheet jams, or manual setup and adjustments for operating the sheet feeding apparatus with different sheet sizes and qualities.

[0006] To this end, the present disclosure provides a sheet feeding device as defined by the independent claims. Further embodiments are provided in the dependent claims.

[0007] According to one aspect of the disclosure, a sheet feeding apparatus is provided. The sheet feeding apparatus comprises a storage surface for a stack of sheets. The storage surface has a leading edge, a trailing edge, and first and second side edges, and the storage surface is adapted to move or be moved vertically between a lower position and an upper position. The sheet feeding apparatus further comprises a blower device. The blower device comprises a plurality of side blower units disposed along the first and second side edges of the storage surface, and a front blower unit disposed along the leading edge of the storage surface. The blower device further comprises at least one fan configured to provide one or more air flows to each of the side blower units and the front blower unit. The plurality of side blower units and the front blower unit are configured to direct one or more air flows toward an upper region of the sheet feeding apparatus to float a plurality of upper sheets of the stack of sheets. The sheet feeding apparatus further comprises a vacuum belt feeder configured to grab and feed a top sheet of the plurality of floated sheets. The blower apparatus further comprises a heating unit disposed between a first fan of the at least one fan and the front blower unit. The heating unit is configured to heat one or more air flows provided to the front blower unit by the first fan.

[0008] The present disclosure is based on the recognition that problems associated with double-feeding, sheet jams, or manual setup and adjustments for operating a sheet feeder with different sheet sizes and qualities, are affected by the temperature and / or humidity of the sheets being managed by the sheet feeder. Furthermore, the adverse effects of humidity are accentuated when dealing with coated sheets.

[0009] The temperature and / or humidity of the bundle of sheets depends on the humidity and / or temperature of the environment in which the bundle of sheets was stored before being inserted into the sheet feeder. In normal operation, the bundle of sheets and the sheet feeder are stored in the same environment, i.e., the air of the environment, for at least one or more days before the bundle of sheets is inserted into the sheet feeder, which is long enough for the bundle of sheets to be affected by the characteristics of the environment. Thus, the temperature and / or humidity of the bundle of sheets depends on the temperature and / or humidity of the air of the environment. Since warmer air can hold more water than cooler air, the relationship between the temperature of air and the humidity of air is such that the (relative) humidity of the air decreases as the air gets hotter. Thus, by heating the air of the environment and / or the bundle of sheets inserted into the sheet feeder, the humidity may be reduced, thereby alleviating the identified problem. However, it may not be appropriate or affordable to heat the air of the environment to a sufficient extent. Furthermore, heating the stack of sheets is not suitable because the stack of sheets will be heated from the outside to the inside, which will cause the center of the stack of sheets to have a different temperature, and therefore a different humidity, than the outer portions of the stack of sheets.

[0010] The present disclosure is further based on the realization that too much humidity is only a problem for the top sheets. That is, if the humidity of the two top sheets is high enough that they stick to each other, it may result in double feeding and / or sheet jams. On the other hand, if it is ensured that the humidity of the two top sheets is low enough, double feeding and / or sheet jams can be prevented. Thus, a sheet feeding device according to one aspect of the present disclosure provides heating of the air stream that is used to float the top sheets of a stack of sheets. Thus, the heated air stream is directed exactly where the heat is needed, thereby minimizing the risk of double feeding and / or sheet jams of at least the two top sheets and reducing energy consumption compared to heating the entire stack of sheets.

[0011] The front blower unit and the side blower units are located along the front edge and the first and second side edges of the storage surface such that the airflow directed to the upper region of the sheet feeder for flotation is directed from three different directions, and thus the flotation of the upper sheets can be understood as a coordinated operation performed by the side blower units and the front blower unit.

[0012] The front blower unit and the heating unit of the blower device together provide a heated airflow, where the heated airflow reaches the plurality of top sheets at the leading edge of the storage surface and travels along the plurality of top sheets toward the trailing edge of the storage surface. Furthermore, because the side blower units provide at least a portion of the floating of the plurality of topmost sheets, the side blower units help separate the topmost sheets so that the heated airflow can more easily travel along the plurality of floated topmost sheets from the leading edge to the trailing edge. Thus, the front blower unit and the heating unit, together with the side blower units, have a synergistic effect of allowing the hot air to travel along the plurality of floated topmost sheets.

[0013] The first blower unit may be further configured to direct the one or more air streams in a direction substantially perpendicular to the leading edge such that a greater portion of the air stream heated by the heating unit travels along the plurality of raised top sheets from the leading edge to the trailing edge, thereby further minimizing problems caused by humidity.

[0014] The sheet feeding apparatus may further comprise a flow path configured to guide the airflow(s) from the first fan to the front blower unit. The flow path may increase the amount of air in the airflow(s) from the first fan that reaches the front blower unit, thereby increasing the efficiency of the sheet feeding apparatus. A heating unit may be disposed within the flow path, which may increase the amount of air in the airflow from the first fan that is exposed to the heating of the heating unit, thereby increasing the efficiency of the sheet feeding apparatus. Furthermore, the flow path may be configured to guide the airflow from the first fan to the heating unit to further increase the amount of air in the airflow from the first fan that will be exposed to the heating of the heating unit.

[0015] The heating unit may include at least one resistive wire configured to generate heat. The heating unit may further be configured to heat one or more air flows supplied to the front blower unit via the at least one resistive wire. The at least one wire may be configured to receive an electric current passing through the at least one wire, thereby heating the at least one wire. The resistive wires of the at least one resistive wire and / or at least a portion of the at least one wire may extend along and / or across a path of one or more air flows supplied to the front blower unit by the first fan. Thus, the one or more air flows may flow along and / or across the resistive wire or a portion of the resistive wire on the way to the front blower unit, thereby being heated. The resistive wire or a portion of the resistive wire may be arranged in contact with the one or more air flows, thereby increasing the efficiency of the heating. At least a portion of the resistive wires of the at least one resistive wire may be arranged along a coiled or wound path. The coiled or wound path may be arranged in a plane. However, the coiled or wound path may be along at least a portion of the surface of a three-dimensional geometric shape, where the geometric shape may be, for example, a cylinder, a cone, a pyramid, a prism, a tetrahedron, or a rectangular parallelepiped. For example, the resistive wire may be arranged along a coiled path along the surface of a cone, the coiled path being arranged along the surface of the cone so as to extend along the longitudinal direction of the cone and across a plane perpendicular to the longitudinal direction. The heating unit may include multiple resistive wires arranged at different locations along one or more airflow paths.

[0016] The blower device may further comprise a second heating unit disposed between a second fan of the at least one fan and the front blower unit. The second heating unit may be configured to heat one or more air flows provided by the second fan to the front blower unit. The second heating unit may provide additional heating that may further minimize problems associated with, for example, double feeding and sheet jamming. The second fan and the first fan may be two different fans of the at least one fan, for example disposed on different sides of the sheet feeder. However, the first fan and the second fan may be the same and configured to provide two or more air flows to the front blower unit.

[0017] The blower device may further comprise at least one side heating unit arranged between the third fan of the at least one fan and a side blower unit of the plurality of side blower units. Thereby, heating of the lifted top sheet may be increased and / or spread more evenly along the lifted top sheet. By providing heated air flows from multiple directions, problems associated with, for example, double feeding and / or sheet jamming may be further mitigated. The at least one side heating unit may be configured to heat one or more air flows provided by the third fan to said side blower unit. The blower device may comprise two side heating units, each arranged between a respective side blower unit and the third fan of the at least one fan. The blower device may comprise, for example, two third fans. The third fan(s), the second fan, and / or the first fan may be the same fan of the at least one fan.

[0018] The sheet feeding apparatus may further comprise a sensor unit configured to measure humidity and / or temperature in or within the sheet feeding apparatus and / or the ambient air. The ambient air may be the air surrounding the sheet feeding apparatus and / or the air of the environment in which the sheet feeding apparatus is located. The air in the sheet feeding apparatus and the ambient air may be in fluid communication such that the ambient air may flow into the sheet feeding apparatus. The at least one fan may be configured to draw air from the ambient air. The sheet feeding apparatus may further be configured to adjust the amount of air provided by the at least one fan and / or the amount of heat generated by the heating unit based on the measured humidity and / or temperature. If excess air and / or heat is provided to the floated top sheets, they may dry out, which may cause static electricity to build up between the sheets and cause them to stick together. Adjusting the amount of air and / or heat can ensure that the floated top sheet is sufficiently dehumidified and / or not completely dry, thereby reducing the risk of double feeding and / or sheet jams.

[0019] Other objects, features, and advantages of the enclosed embodiments will become apparent from the following detailed disclosure, the appended dependent claims, as well as the drawings.

[0020] It is noted that embodiments of the present invention relate to all possible combinations of the features recited in the claims. Furthermore, it will be understood that the various embodiments described for the method defined according to the first aspect, the fault detection system according to the second aspect and the embodiments described for the fault detection device according to the third aspect can all be combined with each other. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 illustrates a perspective view of a sheet feeding apparatus according to an exemplary embodiment of the present disclosure. [Diagram 2] FIG. 2 illustrates a side view of a sheet feeding apparatus according to an exemplary embodiment of the present disclosure. [Diagram 3]FIG. 3 illustrates a perspective view of a sheet feeding apparatus according to an exemplary embodiment of the present disclosure. [Figure 4] FIG. 4 illustrates a cross-sectional view of a sheet feeding apparatus according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] FIG. 1 illustrates a perspective view of a sheet feeding apparatus 1 according to an exemplary embodiment of the present disclosure.

[0023] The sheet feeding device 1 comprises a storage surface 11 for a stack of sheets (not shown, see FIG. 3), a blower device comprising two side blower units 21 and a front blower unit (not shown, see FIG. 3), three fans 23 (two of which are shown in FIG. 1) and a vacuum belt feeder 30.

[0024] Two side blower units 21 are provided along the first and second side edges 11c, 11d, respectively, of the storage surface 11. A front blower unit is provided below the vacuum belt feeder 30 along the front edge 11a of the storage surface 11. A first one of these fans 23 is configured to supply an air flow (not shown, see FIG. 3) to the front blower unit and a second one of these fans 23 is configured to supply an air flow to the side blower unit 21. The front blower unit and the side blower unit 21 are configured to direct said air flow towards an upper region of the sheet feeding device 1 in order to lift the top sheets of the stack of sheets.

[0025] The storage surface 11 is adapted to move vertically between a lower position and an upper position, where the vacuum belt feeder 30 is configured to grab and deliver a topmost sheet of the plurality of floated sheets, such that the storage surface 11, the blower device, and the vacuum belt feeder 30 cooperate to maintain the plurality of topmost sheets in an upper region by raising or lowering the storage surface 11, floating the plurality of topmost sheets with the blower device, and delivering the topmost sheet with the vacuum belt feeder 30.

[0026] The sheet feeding device 1 further comprises a heating unit (not shown, see Figure 2 or Figure 3) arranged between fan 23 of the at least one fan and the front blower unit and configured to heat one or more air flows supplied to the front blower unit by the first fan.

[0027] The sheet feeding apparatus 1 may include a control device (not shown). The control device may be configured to move the storage surface 11 between a lower position and an upper position. The control device may be further configured to control the vacuum belt feeder 30, the fan 23, and the heating unit.

[0028] The sheet feeding apparatus 1 may include a sensor unit (not shown) configured to measure the humidity and / or temperature of at least one of the air in the sheet feeding apparatus 1 and the ambient air. The sheet feeding apparatus 1 may be further configured to adjust the amount of air supplied by the at least one fan and / or the amount of heat generated by the heating unit based on the measured humidity and / or temperature, where the adjustment may be made by a controller of the sheet feeding apparatus 1, which may be communicatively connected to the sensor unit.

[0029] Fig. 2 illustrates a side view of a sheet feeding apparatus 1 according to an exemplary embodiment of the present disclosure. It should be noted that Fig. 2 comprises the features, elements, and / or functions as shown in Fig. 1 and described in the associated text. Therefore, for a better understanding, reference should also be made to Fig. 1 and the associated description of Fig. 1.

[0030] The side view of the sheet feeding apparatus 1 in Figure 2 shows one side blower unit 21 and a second fan 23 disposed below the side blower unit 21 and configured to provide one or more air flows to the side blower unit 21. Figure 2 further shows the first fan 23 disposed below a front blower unit (not shown, see Figure 3) and a vacuum belt feeder 30.

[0031] 2 further includes a flow path 24. The flow path 24 is disposed between the first fan 23 and the front blower unit. The flow path 24 is configured to guide one or more air flows from the first fan 23 to the front blower unit.

[0032] The sheet feeder 1 includes a heating unit 40. The heating unit 40 is disposed in the flow path 24 and configured to heat one or more air flows provided by the first fan 23 to the front blower unit. The heating unit 40 may include at least one resistive wire configured to generate heat. The heating unit 40 shown in FIG. 2 is disposed on the same side of the sheet feeder 1 as the front blower unit 23 is disposed.

[0033] Fig. 3 illustrates a side view of a sheet feeding apparatus 1 according to an exemplary embodiment of the present disclosure. It should be noted that Fig. 3 comprises the features, elements, and / or functions as shown in Fig. 1 and Fig. 2 and described in the associated text. Therefore, for a better understanding, reference should also be made to Fig. 1 and Fig. 2 and their associated descriptions.

[0034] The sheet feeder 1 comprises a heating unit 40 arranged below the front blower unit 22, and therefore on the same side of the sheet feeder 1. The heating unit 40 may be connected between one or more first fans (not shown, see Figures 1, 2 and 4) of the sheet feeder 1 and the front blower unit 22. Furthermore, the sheet feeder 1 may comprise one or more flow paths (not shown, see Figures 2 and 4). Furthermore, the heating unit 40 may be arranged in one or more flow paths or form part of one or more flow paths.

[0035] Fig. 4 illustrates a cross-sectional view of a sheet feeding apparatus 1 according to an exemplary embodiment of the present disclosure. It should be noted that Fig. 4 includes the features, elements, and / or functions as shown in Figs. 1-3 and described in the associated text. Therefore, for a better understanding, reference should also be made to Figs. 1-3 and their associated descriptions.

[0036] 4 shows a portion of the sheet feeder 1 on which is disposed a stack of sheets 5. It should be understood that the stack of sheets 5 is disposed on a storage surface (not shown) of the sheet feeder 1 adapted for vertical movement, thereby causing the stack of sheets 5 to move vertically.

[0037] The sheet feeding apparatus 1 includes a front blower unit 22 configured to receive one or more air flows, indicated by arrows in FIG. 4, from a first fan (not shown, see FIGS. 1, 2 and 3) and to direct one or more air flows toward the upper region 12 of the sheet feeding apparatus 1 to lift multiple upper sheets 5b, 5a of the stack of sheets 5 within the upper region 12.

[0038] The vacuum belt feeder 30 is positioned above the front blower unit 22 and the stack of sheets 5 and is configured to grab and feed the topmost sheet 5b of the plurality of floated top sheets 5a, 5b.

[0039] The sheet feeding apparatus 1 further includes a flow path 24. One end of the flow path 24 is connected to the front blower unit 22. The other end (not shown) of the flow path 24 may be connected to a first fan (not shown, see Figures 1, 2 and 3).

[0040] The sheet feeding apparatus 1 further comprises a heating unit 40. The heating unit 40 is disposed within the flow path 24. The heating unit 40 is configured to heat one or more air flows flowing through the flow path 24. The heating unit 40 shown in FIG. 4 comprises a resistive wire 41. The resistive wire 41 is disposed along a coiled or zigzag path, thereby extending along and across the path of the one or more air flows. The heating unit 40 may comprise or be connected to a power source (not shown) configured to provide electrical energy to the heating unit 40. It should be understood that the present disclosure is not limited to the heating unit 40 as shown in FIG. 2, and the heating unit 40 may alternatively comprise an alternative heat source, such as, for example, a conduit or container comprising a heated fluid, and / or a radiator.

[0041] While the present invention has been illustrated in the accompanying drawings and the foregoing description, such illustrations should be considered as exemplary or illustrative and not restrictive, and the present invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the appended claims, the term "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be interpreted as limiting the scope.

[0042] Below we provide a numbered list of aspects of the inventive concept, however the scope of protection is defined by the appended claims.

[0043] [List of numbered aspects] 1. A sheet feeding device (1), a storage surface (11) for a stack of sheets (5), said storage surface having a leading edge (11a), a trailing edge (11b) and first and second side edges (11c) and (11d), said storage surface being adapted to move vertically between a lower position and an upper position; A blower device comprising: a plurality of side fan units (21) provided along the first side edge (11c) and the second side edge (11d) of the storage surface; and a front fan unit (22) provided along the front edge of the storage surface; at least one fan (23) configured to supply one or more air flows (3) to each of the side fan units and to the front fan unit; wherein the side blower units and the front blower unit are configured to direct the one or more air streams toward an upper region (12) of the sheet feeding device to lift upper sheets (5a) of the stack (5). A blower device comprising: a vacuum belt feeder (30) configured to grip and feed an uppermost sheet (5b) of the plurality of floated sheets (5a); Equipped with The blower device, a heating unit (40) disposed between a first fan (23) of the at least one fan and the front blower unit and configured to heat the one or more air flows supplied by the first fan to the front blower unit; The sheet feeding device (1) further comprises: 2. The sheet feeding device (1) of claim 1, wherein the first blower unit is further configured to direct the one or more air flows in a direction substantially perpendicular to the leading edge. 3. A flow path (24) configured to guide the airflow from the first fan to the front blower unit; wherein the heating unit is disposed in the flow path. The sheet feeding device (1) according to aspect 1 or 2. 4. The heating unit comprises at least one resistive wire (41) configured to generate heat, the heating unit being further configured to heat the one or more air flows provided to the front blower unit via the at least one resistive wire. The sheet feeding device (1) according to any one of the first to third aspects. 5. The sheet feeding device (1) of aspect 4, wherein a resistive wire of the at least one resistive wire extends along and / or across the path of the one or more air flows supplied to the front blower unit by the first fan. 6. The sheet feeding device (1) of aspect 5, wherein at least a portion of the at least one resistive wire is arranged along a coiled or wound path. 7. The blower device is a second heating unit (40) disposed between a second one of the at least one fan and the front blower unit and configured to heat the one or more air flows supplied by the second fan to the front blower unit; The sheet feeding device (1) according to any one of aspects 1 to 6, further comprising: 8. The blower device is at least one side heating unit (40) disposed between a third fan of the at least one fan and a side blower unit of the plurality of side blower units and configured to heat the one or more air flows supplied to the side blower unit by the third fan; The sheet feeding device (1) according to any one of aspects 1 to 7, further comprising: 9. The sheet feeding device further includes a sensor unit configured to measure the humidity and / or temperature of at least one of the air in the sheet feeding device and the ambient air; wherein the sheet feeding device is further configured to adjust an amount of air supplied by the at least one fan and / or an amount of heat generated by the heating unit based on the measured humidity and / or temperature. The sheet feeding device (1) according to any one of the first to eighth aspects.

Claims

1. A sheet feeding device (1), a storage surface (11) for a stack of sheets (5), said storage surface having a leading edge (11a), a trailing edge (11b) and first and second side edges (11c) and (11d), adapted to move vertically between a lower position and an upper position; A blower device comprising: a plurality of side fan units (21) disposed along the first side edge (11c) and the second side edge (11d) of the storage surface; and a front fan unit (22) disposed along the front edge of the storage surface; at least one fan (23) configured to supply one or more air flows (3) to each of said side fan units and to said front fan unit; wherein the side blower units and the front blower unit are configured to direct the one or more air flows toward an upper region (12) of the sheet feeding device to lift upper sheets (5a) of the stack (5). A blower device comprising: a vacuum belt feeder (30) configured to grip and feed the topmost sheet (5b) of the plurality of floated sheets (5a); Equipped with The blower device, a heating unit (40) disposed between a first fan (23) of the at least one fan and the front blower unit and configured to heat the one or more air flows supplied by the first fan to the front blower unit; at least one side heating unit (40) disposed between a third fan of the at least one fan and a side blower unit of the plurality of side blower units and configured to heat the one or more air flows supplied to the side blower unit by the third fan; The sheet feeding device (1), further comprising:

2. The sheet feeding apparatus (1) of claim 1, wherein the front blower unit is further configured to direct the one or more air streams in a direction substantially perpendicular to the leading edge.

3. a flow passage (24) configured to guide the airflow from the first fan to the front blower unit; wherein the heating unit is disposed in the flow path. A sheet feeding device (1) according to claim 1 or 2.

4. the heating unit comprises at least one resistive wire (41) configured to generate heat, the heating unit being further configured to heat the one or more air flows provided to the front blower unit via the at least one resistive wire. A sheet feeding device (1) according to any one of the preceding claims.

5. 5. The sheet feeding device (1) of claim 4, wherein a resistive wire of the at least one resistive wire extends along and / or across a path of the one or more air flows supplied by the first fan to the front blower unit.

6. 6. The sheet feeding device (1) according to claim 5, wherein at least a portion of the resistive wires of the at least one resistive wire are arranged along a coiled or wound path.

7. The blower device is a second heating unit (40) disposed between a second one of the at least one fan and the front blower unit and configured to heat the one or more air flows supplied by the second fan to the front blower unit; The sheet feeding device (1) according to any one of the preceding claims, further comprising:

8. a sensor unit configured to measure humidity and / or temperature of at least one of the air in the sheet feeding device and the ambient air, wherein the sheet feeding device is further configured to adjust an amount of air supplied by the at least one fan and / or an amount of heat generated by the heating unit based on the measured humidity and / or temperature. A sheet feeding device (1) according to any one of the preceding claims.

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