WO2023174599A1

WO2023174599A1 - Sheet feeding device comprising a heating unit

Info

Publication number: WO2023174599A1
Application number: PCT/EP2023/051575
Authority: WO
Inventors: Patrik Dahlqvist; Fredrik IRLÉN
Original assignee: Plockmatic International Aktiebolag
Priority date: 2022-03-14
Filing date: 2023-01-23
Publication date: 2023-09-21
Also published as: SE2250320A1

Abstract

A sheet feeding device (1) is provided. The sheet feeding device comprises 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), at least one fan (23) configured to supply one or more air streams (3) to each of the side blower units and the front blower unit. The plurality 5of side blower units and the front blower unit are configured to direct the one or more air streams towards an upper region (12) of the sheet feeding device for floating a plurality of upper sheets (5a) of the stack of sheets. The sheet feeding device further comprises a vacuum belt feeder (30) configured to grab and feed away an uppermost sheet (5b) of the plurality of floated sheets. The blower arrangement further comprises a heating unit (40) 10arranged 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 streams supplied by the first fan to the front blower unit.

Description

SHEET FEEDING DEVICE COMPRISING A HEATING UNIT

Technical field

The present disclosure relates to sheet feeding devices for the printing industry, for example sheet feeding devices for printers, copiers or sorters.

Background

Sheet feeding devices are commonly integrated into printers or copiers and are manually loaded with a large number of sheets in order to automatically provide sheets, one by one, for a subsequent operation on the sheet, such as printing or sorting.

One example of a prior art sheet feeding device by the present applicant is described in the Swedish patent specification published under number SE 540 166 C2, which discloses a paper feeding device. The paper feeding device comprises a storage surface for stack of papers which is adapted to be moved between a lower position and an upper position, a vacuum feeder for feeding papers from their position on the storage surface, and a blower arrangement adapted to provide a curtain of air separating an uppermost sheet of paper from the rest of the stack of papers.

A challenge for sheet feeding devices is to manage sheets of various materials and qualities whilst minimizing or eliminating problems associated with double-feed, sheet jam or manual configuration and adjustment for operating the sheet feeding device with different sheet sized and qualities. It is therefore of interest to reduce problems associated with doublefeed, sheet jam or manual configuration and adjustment for operating the sheet feeding device with different sheet sized and qualities.

Summary

It is therefore a goal to provide a sheet feeding device with reduced problems associated with double-feed, sheet jam or manual configuration and adjustment for operating the sheet feeding device with different sheet sized and qualities. To achieve this goal, the present disclosure provides a sheet feeding device, as defined by the independent claim. Further embodiment are provided in the dependent claims.

According to an aspect of the present disclosure, a sheet feeding device is provided. The sheet feeding device comprises a storage surface for a stack of sheets. The storage surface has a leading edge, a trailing edge, and a first and a second side edge, the storage surface is adapted to move, or to be moved, vertically between a lower position and an upper position. The sheet feeding device further comprises a blower arrangement. The blower arrangement comprises a plurality of side blower units provided along the first side edge and the second side edge of the storage surface, and a front blower unit provided along the leading edge of the storage surface. The blower arrangement further comprises at least one fan configured to supply one or more air streams 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 the one or more air streams towards an upper region of the sheet feeding device for floating a plurality of upper sheets of the stack of sheets. The sheet feeding device further comprises a vacuum belt feeder configured to grab and feed away an uppermost sheet of the plurality of floated sheets. The blower arrangement further comprises a heating unit arranged between a first fan of the at least one fan and the front blower unit. The heating unit is configured to heat the one or more air streams supplied by the first fan to the front blower unit.

The present disclosure is based on the realization that the problems related to double-feed, sheet jam or manual configuration and adjustment for operating the sheet feeding device with different sheet sized and qualities, are affected by the temperature and/or the humidity of the sheets being managed by the sheet feeding device. Further, the negative impact of humidity is emphasized when dealing with coated sheets.

The temperature and/or the humidity of the stack sheets is dependent on the humidity and/or temperature of the environment in which the stack of sheets were stored in prior to being inserted into the sheet feeding device. In normal operations, the stacks of sheets and the sheet feeding device are stored in the same environment, i.e. the air of the environment, at least the day, or days, before the stack of sheets are inserted into the sheet feeding device, which is long enough for the stack of sheets to be affected by the characteristics of the environment. Therefore, the temperature and/or the humidity of the stack of sheets is dependent on the temperature and/or the humidity of the air of the environment. Since warmer air is able to hold more water than colder air, the relationship between the temperature of the air and the humidity of the air is that the (relative) humidity of the air decreases as the air gets hotter. Thus, by heating the air of the environment and/or the stack of sheets inserted in the sheet feeding device, the humidity may be decreased, thereby mitigating the identified problems. However, heating the air of the environment to a sufficient degree may not be suitable or affordable. Moreover, heating the stack of sheets is not suitable as the stack of sheets would be heated from outside-in, which would result in the center of the stack of sheets having a different temperature, and thereby humidity, than the outer portions of the stack of sheets.

The present disclosure is further based on the realization that a too high degree of humidity is only an issue for the uppermost sheets. As in, if the humidity of the two uppermost sheets is high enough for them to stick together it may result in a double-feed and/or sheet jam. On the other hand, if it can be made sure that the humidity of the two uppermost sheets is low enough, a double feed and/or a sheet jam may be prevented. The sheet feeding device according to an aspect of the present disclosure therefore provides heating of the air streams which are being used to float the upper sheets of the stacks of sheets. Thus, the heated air streams are directed exactly to where the heat is needed, thereby minimizing the risk of double-feed and/or sheet jam of at least the two uppermost sheets, and reducing the energy consumption in comparison to heating the entire stack of sheets.

The front blower unit and the plurality of sides blower units being provided along the leading edge and the first and second side edges of the storage surface causes the air streams being directed to the upper region of the sheet feeding device for floating to being directed from three different directions. The floating of the plurality of upper sheets may therefore be understood as a coordinated effort performed by the side blower units and the front blower unit.

The front blower unit and the heating unit of the blower arrangement together provides heated air streams, wherein the heated air streams reaches the plurality of upper sheets at the leading edge of the storage surface and travels along the plurality of upper sheets towards the trailing edge of the storage surface. Further, as the side blower units provides at least some of the floating of the plurality of uppermost sheets, the side blower units help separating the uppermost sheets, such that the heated air streams is able to more easily travel along the plurality of floated uppermost 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 heat air to travel along the plurality of floated uppermost sheets.

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. Therefore, a larger degree of the air streams, which have been heated by the heating unit, may travel along the plurality of floated uppermost sheets, from the leading edge to the trailing edge, thereby further minimizing the problems caused by humidity.

The sheet feeding device may further comprise a channel configured to guide the air stream(s) from the first fan to the front blower unit. The channel may increase the amount of air of the air stream(s) from the first fan which reaches the front blower unit, thereby increasing the efficiency of the sheet feeding device. The heating unit may be arranged within the channel, which may increase the amount of air of the air stream from the first fan being exposed to the heating of the heating unit, thereby increasing the efficiency of the sheet feeding device. Further, the channel may be configured to guide the air stream from the first fan to heating unit to further increase the amount of air of the air stream from the first fan to be exposed to the heating of the heating unit.

The heating unit may comprise at least one resistive wire configured to generate heat. The heating unit may be further configured to heat the one or more air streams supplied to the front blower unit via the at least one resistive wire. The at least one wire may be configured for receiving an electrical current which travels through the at least one wire, thereby heating up the at least one wire. A resistive wire of the at least one resistive wire, and/or at least a portion of the at least one wire, may be extending along and/or across a path of the one or more air streams supplied by the first fan to the front blower unit. Thus, the one or more air streams may flow along and/or across the resistive wire, or the portion of a resistive wire, on the way to the front blower unit, thereby being heated. By the resistive wire, or the portion of a resistive wire, being arranged so as to be in contact with the one or more air streams, the efficiency of the heating may be increased. At least a portion of the resistive wire of the at least one resistive wire may be arranged along a coiling or winding path. The coiling or winding path may be arranged in a plane. However, the coiling or winding path may be along at least a portion of a surface of a three-dimensional geometrical shape, wherein the geometrical shape may be, for example, a cylinder, a cone, a pyramid, a prism, a tetrahedon or a cuboid. For example, the resistive wire may be arranged along a coiling path along a surface of a cone, wherein the coiling path is arranged along the surface of the cone so as to extend along a longitudinal direction of the cone and across a plane perpendicular to the longitudinal direction. The heating unit may comprise a plurality of resistive wires arranged, which may be arranged at different locations along the path of the one or more air streams.

The blower arrangement may further comprise a second heating unit arranged between a second fan of the at least one fan and the front blower unit. The second heating unit may be configured to heat the one or more air streams supplied by the second fan to the front blower unit. The second heating unit may provide additional heating which may further minimize the problems associated with, for example, double-feed and sheet jam. The second fan and the first fan may be two different fans of the at least one fan, which may be arranged at, for example, different sides of the sheet feeding device. However, the first fan and the second fan may be the same and may be configured to deliver two or more air streams to the front blower unit.

The blower arrangement may further comprise at least one side heating unit arranged between a third fan of the at least one fan and a side blower unit of the plurality of side blower units. Thereby, the heating of the floated uppermost sheets may be increased and/or more evenly spread out along the floated uppermost sheets. By providing heated air streams from a plurality of directions, the problems associated with, for example, doublefeed and/or sheet jam may be further mitigated. The at least one side heating unit may be configured to heat the one or more air streams supplied by the third fan to said side blower unit. The blower arrangement may comprise two side heating units, each arranged between a respective side blower unit and a third fan of the at least one fan. The blower arrangement 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.

The sheet feeding device may further comprise a sensor unit configured to measure humidity and/or temperature within, or inside, the sheet feeding device and/or ambient air. The ambient air may be the air surrounding the sheet feeding device and/or the air of the environment in which the sheet feeding device is arranged. The air within the sheet feeding device and the ambient air may be in fluid communication, such that ambient air may flow into the sheet feeding device. The at least one fan may be configured to draw air from the ambient air. The sheet feeding device may be 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. If too much air and/or heat is provided to the floated uppermost sheets, they may be dried out, which may cause static electricity to build up between them which may cause them to stick together. The adjustment of amount of air and/or amount of heat may ensure that the floated uppermost sheets are sufficiently dehumidified and/or not dried out, thereby reducing the risk of double-feed and/or sheet jam.

Other objectives, features and advantages of the enclosed embodiments will be apparent from the following detailed disclosure, from the attached dependent claims as well as from the drawings.

It is noted that embodiments of the invention relate to all possible combinations of features recited in the claims. Further, it will be appreciated that the various embodiments described for the method as defined in accordance with the first aspect, the embodiments described for the fault locator system according to the second aspect and the fault locator device according to the third aspect are all combinable with each other.

Brief description of drawings

Fig. 1 shows a perspective view of a sheet feeding device according to an exemplary embodiment of the present disclosure. Fig. 2 shows a side view of a sheet feeding device according to an exemplary embodiment of the present disclosure.

Fig. 3 shows a perspective view of a sheet feeding device according to an exemplary embodiment of the present disclosure.

Fig. 4 shows cross-section of a sheet feeding device according to an exemplary embodiment of the present disclosure.

Detailed description

Fig. 1 shows a perspective view of a sheet feeding device 1 according to an exemplary embodiment of the present disclosure.

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

The two side blower units 21 are provided along a respective side edge lie, lid of the first and second side edges lie, lid of the storage surface 11. The front blower unit is provided along a leading edge 11a of the storage surface 11, below the vacuum belt feeder 30. A first fan 23 of the fans 23 is configured to supply air streams (not shown; see Fig. 3) to the front blower unit and second fans 23 of the fans 23 are configured to supply air streams to the side blower units 21. The front blower unit and the side blower units 21 are configured for directing said air streams towards an upper region of the sheet feeding device 1 for floating a plurality of upper sheets of the stack of sheets.

The storage surface 11 is adapted to move vertically between a lower position and an upper position, wherein the vacuum belt feeder 30 is configured to grab and feed away an uppermost sheet of the plurality of floated sheets. Thereby, the storage surface 11, the blower arrangement and the vacuum belt feeder 30 works in coordination to maintain a plurality of uppermost sheets within the upper region, by raising or lowering the storage surface 11, and floating the plurality uppermost sheets, by the blower arrangement, and feeding away an uppermost sheet, by the vacuum belt feeder 30. The sheet feeding device 1 further comprises a heating unit (not shown; see Fig. 2 or 3) arranged between the fan 23 of the at least one fan and the front blower unit, and configured to heat the one or more air streams supplied by the first fan to the front blower unit.

The sheet feeding device 1 may comprise a controller (not shown). The controller may be configured to cause the storage surface 11 to move between the lower position and the upper position. The controller may be further configured to control the vacuum belt feeder 30, the fans 23 and the heating unit.

The sheet feeding device 1 may comprise a sensor unit (not shown) configured to measure humidity and/or temperature of at least one of air within the sheet feeding device 1 and ambient air. The sheet feeding device 1 may be 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, wherein the adjustment may be performed by a controller of the sheet feeding device 1, which may be communicatively connected to the sensor unit.

Fig. 2 shows a side view of a sheet feeding device 1 according to an exemplary embodiment of the present disclosure. It should be noted that Fig. 2 comprises features, elements and/or functions as shown in Fig. 1 and described in the associated text. Hence, it is also referred to Fig. 1 and the description relating thereto for an increased understanding.

The side view of the sheet feeding device 1 in Fig. 2 shows one side blower unit 21 and a second fan 23 arranged below the side blower unit 21 and configured to supply one or more air streams to the side blower unit 21. Further, Fig. 2 shows a first fan 23 arranged below a front blower unit (not shown; see Fig. 3) and the vacuum belt feeder 30.

The sheet feeding device 1 as shown in Fig. 2 further comprises a channel 24. The channel 24 is arranged between first fan 23 and the front blower unit. The channel 24 is configured to guide one or more air streams from the first fan 23 to the front blower unit.

The sheet feeding device 1 comprises a heating unit 40. The heating unit 40 is arranged within the channel 24, and is configured to heat the one or more air streams supplied by the first fan 23 to the front blower unit. The heating unit 40 may comprise at least one resistive wire configured to generate heat. The heating unit 40 shown in Fig. 2 is arranged at a same side of the sheet feeding device 1 as the front blower unit 23 is arranged.

Fig. 3 shows a side view of a sheet feeding device 1 according to an exemplary embodiment of the present disclosure. It should be noted that Fig. 3 comprises features, elements and/or functions as shown in Figs. 1 and 2 and described in the associated texts. Hence, it is also referred to Figs. 1 and 2 and the descriptions relating thereto for an increased understanding.

The sheet feeding device 1 comprises a heating unit 40 arranged below the front blower unit 22, and thereby on a same side of the sheet feeding device 1. The heating unit 40 may be connected between one or more first fans (not shown; see Figs. 1, 2 and 4) of the sheet feeding device 1 and the front blower unit 22. Further, the sheet feeding device 1 may comprise one or more channels (not shown; see Figs. 2 and 4). Furthermore, the heating unit 40 may be arranged within, or form part of, the one or more channels.

Fig. 4 shows cross-section of a sheet feeding device 1 according to an exemplary embodiment of the present disclosure. It should be noted that Fig. 4 comprises features, elements and/or functions as shown in Figs. 1 to 3 and described in the associated texts. Hence, it is also referred to Figs. 1 to 3 and the description relating thereto for an increased understanding.

Fig. 4 shows a portion of a sheet feeding device 1, in which a stack of sheets 5 are arranged. It is to be understood that the stack of papers 5 is arranged in a storage surface (not shown) of the sheet feeding device 1, which is adapted to move vertically, thereby moving the stack of papers 5 vertically.

The sheet feeding device 1 comprises a front blower unit 22 which is configured to receive one or more air streams, indicated in Fig. 4 by arrows, from a first fan (not shown; see Figs. 1, 2, and 3), and to direct the one or more air streams towards an upper region 12 of the sheet feeding device 1 for floating a plurality of upper sheets 5b, 5a of the stack of sheets 5 within the upper region 12. The vacuum belt feeder 30 is arranged above the front blower unit 22 and the stack of sheets 5 and is configured to grab and feed away an uppermost sheet 5b of the plurality of floated uppermost sheets 5a, 5b.

The sheet feeding device 1 further comprises a channel 24. An end of the channel 24 is connected to the front blower unit 22. Another end (not shown) of the channel 24 may be connected to the first fan (not shown; see Figs. 1, 2, and 3).

The sheet feeding 1 device further comprises a heating unit 40. The heating unit 40 is arranged within the channel 24. The heating unit 40 is configured to heat the one or more air streams flowing through the channel 24. The heating unit 40 shown in Fig. 4 comprises a resistive wire 41. The resistive wire 41 is arranged along a coiling, or zigzagging, path, and is thereby extending along and across a path of the one or more air streams. The heating unit 40 may comprise, or be connected to, a power source (not shown) configured to supply the heating unit 40 with electrical energy. It is to be understood that the present disclosure is not limited to a heating unit 40 as shown in Fig. 2, and that the heating unit 40 may alternatively comprise an alternative heat source, such as, for example, a conduit or vessel comprising a heated fluid, and/or a radiator.

While the present invention has been illustrated in the appended drawings and the foregoing description, such illustration is to be considered illustrative or exemplifying and not restrictive; 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 word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does 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 construed as limiting the scope.

In the following, a numbered list of aspects of the present inventive concept is provided. The scope of protection is however defined by the appended claims. Numbered list of aspects

1. Sheet feeding device (1) comprising: a storage surface (11) for a stack of sheets (5), the storage surface having a leading edge (11a), a trailing edge (lib), and a first side edge (11c) and a second side edge (lid) and being adapted to move vertically between a lower position and an upper position; a blower arrangement comprising: a plurality of side blower units (21) provided along the first side edge (11c) and the second side edge (lid) of the storage surface, and a front blower unit (22) provided along the leading edge of the storage surface; at least one fan (23) configured to supply one or more air streams (3) to each of the side blower units and the front blower unit; and wherein the plurality of side blower units and the front blower unit are configured to direct the one or more air streams towards an upper region (12) of the sheet feeding device for floating a plurality of upper sheets (5a) of the stack of sheets (5); and a vacuum belt feeder (30) configured to grab and feed away an uppermost sheet (5b) of the plurality of floated sheets (5a); characterized in that the blower arrangement further comprises: a heating unit (40) arranged 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 streams supplied by the first fan to the front blower unit.

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

3. The sheet feeding device (1) according to claim 1 or 2, further comprising a channel (24) configured to guide the air stream from the first fan to the front blower unit; and wherein the heating unit is arranged within the channel. 4. The sheet feeding device (1) according to any of claims 1 to 3, wherein the heating unit comprises at least one resistive wire (41) configured to generate heat, and wherein the heating unit is further configured to heat the one or more air streams supplied to the front blower unit via the at least one resistive wire.

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

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

7. The sheet feeding device (1) according to any of the preceding claims, wherein the blower arrangement further comprises: a second heating unit (40) arranged between a second fan of the at least one fan and the front blower unit, and configured to heat the one or more air streams supplied by the second fan to the front blower unit.

8. The sheet feeding device (1) according to any of the preceding claims, wherein the blower arrangement further comprises: at least one side heating unit (40) arranged 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 streams supplied by the third fan to said side blower unit.

9. The sheet feeding device (1) according to any of the preceding claims, further comprising: a sensor unit configured to measure humidity and/or temperature of at least one of air within the sheet feeding device and ambient air; and 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.

Claims

1. Sheet feeding device (1) comprising: a storage surface (11) for a stack of sheets (5), the storage surface having a leading edge (11a), a trailing edge (lib), and a first side edge (11c) and a second side edge (lid) and being adapted to move vertically between a lower position and an upper position; a blower arrangement comprising: a plurality of side blower units (21) provided along the first side edge (11c) and the second side edge (lid) of the storage surface, and a front blower unit (22) provided along the leading edge of the storage surface; at least one fan (23) configured to supply one or more air streams (3) to each of the side blower units and the front blower unit; and wherein the plurality of side blower units and the front blower unit are configured to direct the one or more air streams towards an upper region (12) of the sheet feeding device for floating a plurality of upper sheets (5a) of the stack of sheets (5); and a vacuum belt feeder (30) configured to grab and feed away an uppermost sheet (5b) of the plurality of floated sheets (5a); characterized in that the blower arrangement further comprises: a heating unit (40) arranged 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 streams supplied by the first fan to the front blower unit; and at least one side heating unit (40) arranged 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 streams supplied by the third fan to said side blower unit.

2. The sheet feeding device (1) according to 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. The sheet feeding device (1) according to claim 1 or 2, further comprising a channel (24) configured to guide the air stream from the first fan to the front blower unit; and wherein the heating unit is arranged within the channel.

4. The sheet feeding device (1) according to any of claims 1 to 3, wherein the heating unit comprises at least one resistive wire (41) configured to generate heat, and wherein the heating unit is further configured to heat the one or more air streams supplied to the front blower unit via the at least one resistive wire.

8. The sheet feeding device (1) according to any of the preceding claims, further comprising: a sensor unit configured to measure humidity and/or temperature of at least one of air within the sheet feeding device and ambient air; and 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.