Folding device and method for controlling folding

Abstract

A folding device (100) for folding at least one sheet of paper, comprising a first fold roller unit (110), comprising a first roller (112) and a second roller (114) separated by a first distance configured to convey the at least one sheet of paper in a first direction, and a second fold roller unit (12), arranged downstream of the first fold roller unit, comprising a third roller (122) and a fourth roller (124) separated by a second distance, configured to convey paper in the first direction. The folding device comprises a folding element (130), arranged upstream of the first fold roller unit, configured to initiate a folding of paper by pressing on a front side of the paper in the first direction to the first and second rollers. The first fold roller unit is configured to engage a back side of the paper and transport the paper to the third and fourth roller to allow the second fold roller unit to engage the back side of the paper. The folding device comprises a common distancing unit (140), wherein the first fold roller unit and the second fold roller unit are mounted on the common distancing unit, wherein the common distancing unit is configured to adjust the first distance and the second distance and a secondary distancing unit (150) configured to adjust the second distance independently of the common distancing unit.

Description

[0001] FOLDING DEVICE AND METHOD FOR CONTROLLING FOLDING

[0002] FIELD OF THE INVENTION

[0003] The present invention generally relates to a post-processing device for the printing industry. More specifically, the present invention is related to a folding device for folding at least one sheet of paper.

[0004] BACKGROUND OF THE INVENTION

[0005] The use of image forming devices, such as printers, are commonly combined with post-processing devices configured to perform post-processing operations such as folding and stacking of papers into booklets, binding of sheets of the booklet by stapling, trimming edges of the booklet and square folding the bound edge of the booklet. Typically, such post-processing machines for folding papers comprise fold-rollers that provide low friction between the paper and the fold-roller, and thus prevent ripping of the paper.

[0006] However, with the expanding use of jet-ink printers, there is a wish to provide an improved folding device that reduces the risk of smearing the ink, while also minimizing damages to the paper while folding.

[0007] Hence, it is an object of the present invention to provide a folding device where the above mentioned problems are overcome, or at least minimized.

[0008] SUMMARY OF THE INVENTION

[0009] It is of interest to provide a folding device that reduces / prevents damages to the paper when folding.

[0010] It is a further interest to provide a folding device that may be more effective and versatile in regard to folding at least one sheet of paper.

[0011] It is a further interest to provide a folding device that reduces the risk of unwanted transfer of the ink.

[0012] This and other objects are achieved by providing a folding device having the features in the independent claims. Preferred embodiments are defined in the dependent claims.

[0013] Hence, according to a first aspect of the present invention, there is provided a folding device for folding at least one sheet of paper. The folding device comprises a first fold roller unit, comprising a first roller and a second roller separated by a first distance, Di, configured to convey the at least one sheet of paper in a first direction, Vi. The folding device comprises a second fold roller unit, arranged downstream of the first fold roller unit with respect to the first direction, Vi, comprising a third roller and a fourth roller separated by a second distance, D2, configured to convey the at least one sheet of paper in the first direction, Vi. The folding device comprises a folding element, arranged upstream of the first fold roller unit with respect to the first direction, Vi, configured to initiate a folding of the at least one sheet of paper by pressing on a front side of the at least one sheet of paper in the first direction, Vi, to the first and second rollers. The first fold roller unit is configured to engage a back side of the at least one sheet of paper and transport the at least one sheet of paper to the third and fourth roller to allow the second fold roller unit to engage the back side of the at least one sheet of paper. The folding device comprises a common distancing unit, wherein the first fold roller unit and the second fold roller unit are mounted on the common distancing unit, wherein the common distancing unit is configured to adjust the first distance, Di, and the second distance, D2. The folding device comprises a secondary distancing unit configured to adjust the second distance, D2, independently of the common distancing unit.

[0014] Thus, the present invention is based on the concept or idea of providing a folding device wherein a sheet of paper may be folded by using a first and second fold roller unit, with a pair of rollers respectively, configured to convey the sheet of paper in a first direction, wherein a folding element is arranged upstream of the first fold roller unit with respect to the first direction and is configured to initiate / facilitate / being part of the folding process. The first and second fold roller units are mounted on a common distancing unit, wherein the common distancing unit is configured to adjust both the first distance between the two rollers of the first fold roller unit and the second distance between the two rollers of the second fold roller unit. The folding device further comprises a secondary distancing unit configured to adjust the second distance independently of the first distance. Hence, the folding device of the present invention provides a folding of the papers using two fold roller units that convey the sheet of paper together with a folding element, a common distancing unit adjusting the distances between both roller pairs and a secondary distancing unit adjusting the distance between the second fold roller unit.

[0015] The present invention is hereby advantageous in that the folding of a sheet of paper may be done in a more adaptive manner which may better control the pressure upon the paper when folding, in order to reduce the risk of smearing and / or transferring the ink, at least because the pressure distribution on the paper while folding may be more uniform.

[0016] The present invention is further advantageous in that the sheet of paper may have a reduced risk of being damaged while also reducing the risk of transferring the ink. By providing a folding device according to the present invention, an improved control over the pressure distribution is allowed, and hence the risk of ink transfer and damages may be reduced in a more versatile and efficient manner.

[0017] The folding device according to the present invention comprises a first fold roller unit comprising a first roller and a second roller separated by a first distance, Di, configured to convey the sheet of paper in a first direction, Vi. A folding device may be, or be part of, any post-processing device configured to perform post-processing operations, such as folding and stacking of papers into booklets, binding of sheets of the booklet by stapling, trimming edges of the booklet and square folding the bound edge of the booklet. The folding device comprises a second fold roller unit arranged downstream of the first fold roller unit with respect to the first direction, Vi. The second fold roller unit comprises a third roller and a fourth roller, i.e. a pair of rollers, separated by a second distance, D2, and is configured to convey the at least one sheet of paper in the first direction, Vi. By the term “downstream” it is here meant later in time and / or further along in the first direction, such that a sheet of paper being conveyed in the first direction, Vi, by the first and second fold roller units, by the folding device will first be conveyed by the first fold roller unit and secondly by the second fold roller unit. It is to be understood that the first and second fold roller units may convey a sheet of paper at the same time or subsequently.

[0018] The first and second fold roller units comprises in other words a pair of rollers respectively, the rollers in each pair are arranged such that they convey a sheet of paper being engaged by them, e.g. when inserted between them. In each of the two pairs of rollers, one roller may rotate clockwise and one roller may rotate counter-clockwise, such that they convey a sheet of paper in the same direction when the sheet of paper engages both of the rollers and is between the two rollers in a pair, e.g. the first and second roller.

[0019] By the term “convey” it is here meant to transport or move at least one sheet of paper through the sheet feeding device. The sheet of paper is carried through the sheet feeding device by the two roller pairs.

[0020] The folding device further comprises a folding element, which may be viewed as being arranged upstream of the first and second fold roller units. The folding element may be arranged to enter / be inserted between the first pair of fold rollers, i.e. the first fold roller unit, thus aiding the folding of the at least one sheet. The folding element may also be arranged to enter / be inserted between the first and second pair of fold rollers, i.e. the first and second fold roller unit. The folding process is initiated by the folding element moving in a first direction, such that it engages the at least one sheet of paper and applies a force in the first direction.

[0021] The folding device further comprises a common distancing unit. The first fold roller unit and the second fold roller unit are mounted on the common distancing unit. The formulation “mounted on” here means attached, fastened, placed or positioned. The first and second fold roller units may be mounted to the common distancing units by bolts, screws or any suitable or preferred attachment method. The common distancing unit is configured to adjust the first distance, Di, and the second distance, D2. In other words the common distancing unit may adjust the first and second distance at the same time / simultaneously, e.g. with a joint movement of the first and second fold roller units. The folding device further comprises a secondary distancing unit configured to adjust the second distance, D2, independently of the common distancing unit. Independently here means that the secondary distancing unit may adjust the second distance, D2, without adjusting the distance, Di, and / or without moving the common distancing unit. In other words, the common distancing unit affects the first distance, Di, and second distance, D2, simultaneously. The secondary distancing unit determines the second distance, D2. Purely as an example, the common distancing unit may be understood as gross tuning and the secondary distancing unit as fine tuning.

[0022] Furthermore, it is advantageous that the adjustment of the first and second distance may be better coordinated by the common distancing unit and the secondary distancing unit, further providing an improved handling of the at least one sheet.

[0023] According to an embodiment of the present invention, the folding device is configured to, by the common distancing unit, adjust the first distance, Di, and the second distance, D2, based on a thickness, T, of the at least one sheet of paper during a first folding stage, and is configured to, by the secondary distancing unit, adjust the second distance, D2, during a second folding stage. The first folding stage comprises conveying and folding the at least one paper by the first fold roller unit, and the second folding stage comprises conveying and folding the at least one paper by the second fold roller unit.

[0024] The first folding stage comprises conveying the at least one paper by the first fold roller unit. The second folding stage comprises conveying the at least one paper by the second fold roller unit. A folding stage may be a part of a full folding sequence, wherein the full folding sequence may be for performing one or more folding actions at a specific point in the sequence and / or time, e.g. in different folding stages. The folding device may thus be configured to, by the common distancing unit, adjust the first distance, Di, and the second distance, D2, based on a thickness, T, of the at least one sheet of paper, e.g. during a first folding stage.

[0025] Thus, the common distancing unit may be configured to adjust the first distance, Di, and the second distance, D2, based on the thickness, T, of the at least one sheet of paper. This may be advantageous in that the first and second distances, Di, D2, may be adjusted in a more optimal manner, to provide improved pressure distribution, which may lead to reduced risk of transferring the ink and / or damaging the at least one sheet.

[0026] The folding device may further be configured to, by the secondary distancing unit, adjust the second distance, D2, e.g. during a second folding stage.

[0027] In other words, the secondary distancing unit may be configured to adjust the second distance, D2, based on based on a parameter. The parameter may be a thickness, T, of the at least one sheet of paper of the at least one sheet of paper. This is advantageous in that the second distance, D2, may be further adjusted in a more optimal manner, to provide improved pressure distribution, which may lead to reduced risk of transferring the ink and / or damaging the at least one sheet. It is to be understood that the thickness, T, of the at least one sheet of paper may be the thickness of a single sheet or a plurality / stack of sheets.

[0028] The thickness, T, of the at least one sheet of paper may be at least one of a detected parameter and a predetermined parameter. The detected parameter may be detected by the folding device and / or a post processor device including the folding device. The folding device may be configured to detect at least one parameter indicating at least one property of the at least one sheet. By the term “predetermined parameter”, it may here mean a parameter known and / or determined in advance, i.e. a priori. The predetermined parameter may be entered into the device, the folding device or the post processing device, or chosen from an interface, e.g. manually by a user before initiating the folding process.

[0029] The present embodiment provides a folding device that may adjust the folding based on a parameter relevant to the current operation, such as thickness. For example, if the at least one parameter is a detected parameter, the folding device may automatically adjust for a property of the at least one sheet. The present embodiment is advantageous in that the second distance, D2, may be adjusted in a more optimal manner, to provide improved pressure distribution, which may lead to reduced risk of transferring the ink and / or damaging the at least one sheet.

[0030] According to an embodiment of the present invention, the secondary distancing unit may be configured to adjust the second distance, D2, based on the first distance, Di. This is advantageous in that the folding device may allow improved pressure distribution and / or improved control of the distances between the first and second fold roller units. This may be because the distance between the first distance, Di, and the second distance, D2, may be synchronized / match / attuned. In other words, the present embodiment may allow a more coordinated adjustment of the first and second distances.

[0031] According to an embodiment of the present invention, the folding device is configured to, by the secondary distancing unit, adjust the second distance, D2, after the at least one sheet of paper is received by the second fold roller unit. Received by the second fold roller unit may be understood as introduced between the third fold roller and the fourth fold roller. The secondary distancing unit may adjust the second distance, D2, during a second folding stage comprising conveying and folding the at least one paper by the second fold roller unit.

[0032] According to an embodiment of the present invention, at least one of the first, second, third and fourth rollers may comprise a conveying surface comprising rubber. Rubber will provide a surface with higher friction, e.g., compared to metal surfaces. This embodiment is advantageous in that a rubber surface is less prone to smear or in other ways ruin the ink from e.g. a jet-ink printer.

[0033] According to an embodiment of the present invention, the secondary distancing unit may comprise a rotatable eccentric cam arrangement configured to adjust the second distance, D2, upon rotation of the eccentric cam. The secondary distancing unit may further comprise a secondary motor configured to rotate the rotatable eccentric cam arrangement.

[0034] The secondary motor may be any device that is configured to create a mechanical motion to drive the secondary distancing unit, and thereby adjust the second distance, D2, during operation. The eccentric cam may be a disc with its center of rotation ‘off center’, i.e., as the cam rotates it may move the fold rollers in relation to each other, thus adjusting the second distance, D2. The eccentric cam is used to convert rotary motion (of the cam) into a linear reciprocation motion of the fold rollers, thereby increasing or decreasing the second distance, D2. It is to be understood that the rotatable eccentric cam arrangement may comprise one or more rotatable eccentric cam(s), e.g. a pair of rotatable eccentric cams arranged oppositely wherein the rotation of both rotatable eccentric cams changes the second distance, D2. In another example, a single rotatable eccentric cam may adjust the second distance, D2, upon rotation of the single eccentric cam. The present embodiment is advantageous in that the second distance, D2, may be adjusted in a more specific manner. The present embodiment allows the second distance, D2, to be adjusted in a more simple and / or efficient manner. The use of a rotatable eccentric cam arrangement may provide a more simple, compact and / or specific / precise solution for adjusting the second distance, which is advantageous in this context of folding devices where energy efficiency, simplicity, compactness and specificity are desired advantages.

[0035] According to an embodiment of the present invention the rotatable eccentric cam arrangement may comprise a first rotatable eccentric cam configured to adjust the second distance, D2, upon rotation of the first rotatable eccentric cam, and a second rotatable eccentric cam configured to adjust the second distance, D2, upon rotation of the second rotatable eccentric cam. The present embodiment is advantageous in that it may provide an even more simple, compact and / or specific / precise solution for adjusting the second distance. The first rotatable eccentric cam may be related to the third roller. The first rotatable eccentric cam may be configured to adjust the second distance, D2, by moving the third roller. The second rotatable eccentric cam may be configured to adjust the second distance, D2, by moving the fourth roller. The first and second rotatable eccentric cam may be configured to move the third and fourth roller towards each other.

[0036] According to an embodiment of the present invention, the common distancing unit may comprise a first arm, wherein the first roller and the third roller are mounted on the first arm, a second arm, wherein the second roller and the fourth roller are mounted on the second arm, and a primary motor configured to move the first and second arms relative each other, such that the both the first distance, Di, and the second distance, D2, are adjusted. The primary motor may be any device that is configured to create a mechanical motion to drive the common distancing unit, and thereby adjust the first and second distances, Di, D2, during operation. The present embodiment is advantageous in that it provides an improved solution for adjusting the distance, which e.g. allows easier and more efficient control of both the first and second distances, Di, D2. This may lead to further reduced risk of transferring the ink and / or damaging the at least one sheet.

[0037] According to an embodiment of the present invention, the folding device comprises at least one sensor configured to determine at least one of a thickness, T, of the at least one sheet of paper, the number of sheets of the at least one sheet of paper, and a characteristic of the at least one sheet of paper. The at least one sensor may for example be a contact sensor, such as a pressure sensor configured to detect and / or measure a weight and / or pressure. The at least one sensor may be an optical sensor, configured to detect and / or measure a thickness, T, of the at least one sheet of paper. The at least one sensor may be one or more sensors used to determine a detected parameter related to the at least one sheet of paper. The present embodiment is advantageous in that the folding device may provide better folding by more accurate measurements of a thickness of the at least one sheet of paper, which may result in improved folding. Furthermore, the present embodiment provides a more versatile folding device and improved automation of the folding process, requiring less manual input.

[0038] In another embodiment of the present invention, the folding device may be configured to determine a thickness of the at least one sheet of paper by using a processor / control unit. The control unit may be configured to determine / calculate the thickness based on estimations and / or use input.

[0039] According to an embodiment of the present invention, the folding element may comprise a folding blade comprising a straight edge. By having a folding blade with a straight edge a cleaner fold may be achieved. A folding blade with a straight edge have not been possible in combination with metal fold rollers due to the friction and force created. By the term “folding blade” it is here meant a blade-like element. The folding blade may be an elongated element comprising a metal or any other suitable material, such as a hard plastic. A folding knife in this context of a folding device for paper is understood to be a component or mechanism designed to assist in the folding of paper or similar materials. The folding element and / or folding knife is used to create precise creases or folds along predetermined lines in the paper. The folding knife works by applying pressure along the paper's surface, creating a sharp crease that facilitates accurate folding. The folding blade is intended to move in a direction towards the at least one sheet of paper, pushing the at least one sheet of paper such that a fold of the at least one sheet of paper is achieved, in cooperation with the fold rollers. By the term “straight edge” it is here meant that the edge of the folding blade interacting with the at least one sheet of paper is substantially without irregularities, such as grooves, jags, or teeth. In other words, having a straight edge means the edge of the folding blade is smooth and substantially even. The present embodiment is advantageous in that it may reduce the risk of damaging the at least one sheet. According to an embodiment of the present invention, the first fold roller unit may comprise at least one spring element arrangement configured to press at least one of the first roller and the second roller in a second direction, V2, perpendicular to the first direction with a first force, Fi. The spring element arrangement is configured to press at least one of the first roller and the second roller in a second direction perpendicular to the first direction with a first force, Fi. The spring element may be any element / device / unit that is at least partially elastic and at least partially rigid, for example made by metal. The spring element may comprise a form that can return into shape after being compressed or extended. The present embodiment is advantageous in that the risk of ink transferring and damaging the at least one sheet is further reduced, since the first fold roller unit may provide a more consistent pressure distribution on the at least one sheet of paper, in an automatic and predetermined manner. Furthermore, the solution is a practical and efficient way to achieve a more consistent predetermined pressure.

[0040] According to an embodiment of the present invention, the spring element arrangement may comprise a first spring element configured to press the first roller in a second direction, V2, perpendicular to the first direction with a first force, Fi, and a second spring element configured to press the second roller in a third direction, V3, perpendicular to the first direction, and opposite the second direction, with a second force, F2. It is to be understood that the first force, Fi, and the second force, F2, may have the same magnitude or different magnitudes. In a preferred embodiment, the first force, Fi, and the second force, F2, have the same magnitude, i.e. |Fi |=|F2| . The present embodiment is advantageous in that the first fold roller unit may provide an even more consistent pressure distribution on the at least one sheet of paper.

[0041] According to an embodiment of the present invention, the secondary distancing unit may be configured to adjust the second distance, D2, based on at least one of the first force, Fi, and the second force, F2. The present embodiment is advantageous in that the second distance, D2, may be adjusted in an even more optimal manner, to provide improved and more controlled pressure distribution, which may lead to reduced risk of transferring the ink and / or damaging the at least one sheet.

[0042] According to an embodiment of the present invention, the folding device further comprises a control unit configured to control the common distancing unit and the secondary distancing unit.

[0043] In a further embodiment, the control unit is configured to receive a thickness, T, of the at least one sheet of paper, and further configured to control the common distancing unit and the secondary distancing unit. The control unit may receive the thickness, T, from manual input, e.g. from a display or a button, and / or from sensor output, e.g. from a thickness sensor comprised in the folding device. The present embodiment is advantageous in that the folding device may control the different measures for changing the distance between the fold roller units, and thereby better engage and convey the at least one sheet of paper, to reduce damage to the at least one sheet of paper.

[0044] According to a second aspect, there is provided a method for controlling folding at least one sheet of paper, using a folding device according to the fist aspect.

[0045] The method comprises receiving a thickness, T, of at least one sheet of paper, and adjusting the first distance, Di, and the second distance, D2, using the common distancing unit based on the received thickness of the at least one sheet of paper. The method further comprises initiating folding of the at least one sheet of paper by pressing on a front side of the at least one sheet of paper in the first direction, Vi, to a first and second roller, using the folding element, and conveying the at least one sheet of paper by the first fold roller unit to the second fold roller unit. Further, the method comprises initiating adjusting of the second distance, D2, using the secondary distancing unit, and conveying and folding the at least one paper by the second fold roller unit.

[0046] The method according to the second aspect may have / comprise a first folding stage and a second folding stage. The step of initiating folding of the at least one sheet of paper by pressing on a front side of the at least one sheet of paper in the first direction, Vi, to a first and second roller, using the folding element, may be performed / executed in the first folding stage. Further, the step of initiating adjusting of the second distance, D2, using the secondary distancing unit, may be performed / executed in the second folding stage. In other words, the method may comprise initiating the first folding stage, by folding the at least one sheet of paper by pressing on a front side of the at least one sheet of paper in the first direction, Vi, to a first and second roller, using the folding element. Further, the method may comprise initiating the second folding stage, by adjusting the second distance, D2, using the secondary distancing unit.

[0047] This second aspect may generally present the same or corresponding advantages as the first aspect. Effects and features of this second aspect are largely analogous to those described above in connection with the first aspect. Embodiments mentioned in relation to the second aspect are largely compatible with the first aspect.

[0048] Thanks to the method, more accurate control of folding at least one sheet of paper may be provided.

[0049] Further objectives of, features of, and advantages with, the present invention will become apparent when studying the following detailed disclosure, the drawings, and the appended claims. Those skilled in the art will realize that different features of the present invention can be combined to create embodiments other than those described in the following.

[0050] BRIEF DESCRIPTION OF THE DRAWINGS

[0051] This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiment(s) of the invention. Fig. 1 schematically shows a folding device in a cross-section view according to an exemplifying embodiment of the present invention,

[0052] Figs. 2a-c schematically show a folding device in a cross-section view according to an exemplifying embodiment of the present disclosure in three stages of the folding process, illustrating a sheet of paper being folded.

[0053] Figs. 3a-b schematically show a folding device in a cross-section view according to an exemplifying embodiment of the present disclosure.

[0054] DETAILED DESCRIPTION

[0055] Fig. 1 schematically shows a cross-sectional view of a folding device 100 according to an exemplifying embodiment of the present invention. The folding device 100 comprises a first fold roller unit 110 and a second fold roller unit 120. The first fold roller unit 110 comprises a first roller 112 and a second roller 114. The first fold roller unit 112 is configured to convey the at least one sheet of paper in a first direction, Vi. The first roller 112 and the second roller 114 are separated by a first distance, Di. The first distance Di is adjustable in a direction substantially orthogonal to the first direction Vi.

[0056] The second fold roller unit 120 comprises a third roller 122 and a fourth roller 124 separated by a second distance, D2. The second fold roller unit 122 is configured to convey the at least one sheet of paper in the first direction, Vi, i.e. the same direction as the first fold unit 112 conveys the at least one sheet of paper.

[0057] The first and second distances, Di and D2, between the first and second fold rollers 112, 114 and the third and fourth fold rollers 122, 124, are adjusted with a common distancing unit 140. That is, the first fold roller unit 110 and the second fold roller unit 120 are mounted on the common distancing unit 140, and the common distancing unit 140 is configured to adjust the first distance, Di, and the second distance, D2.

[0058] In the illustrative example of Fig. 1, the common distancing unit 140 is shaped as two arms, intended to move towards and away from each other, decreasing or increasing the first distance, Di, and the second distance, D2. An increased distance may also be referred to as the fold rollers being opened, or in an open position. The fold rollers are opened, i.e. the first and second distances, Di, D2, are increased by movement of the common distancing unit 140, to enable to fold device 100 to receive at least one sheet paper to be folded, in a space between the fold rollers, i.e. between the first fold roller 112 and second fold roller 114 and between the third fold roller 122 and fourth fold roller 124. The rotating movement of the arms of the common distancing unit 140 is indicated by arrows A and B. Hence, the two arms rotate around a respective pivot point. However, it should be understood that the rotational movement of the common distancing unit 140 in this illustrated example may be replaced and / or combine with a linear movement in another exemplary embodiment. The folding device 100 comprises a secondary distancing unit 150, in the illustrated example shown as a pair of eccentric cams. The secondary distancing unit 150 is configured to adjust the distance, D2, by moving the fold rollers 122, 124 of the second fold roller unit 120. The secondary distancing unit 150 may be configured to adjust the second distance, D2, based on the first distance, Di, such that the two distances, Di and D2, may be adapted relative each other, for optimizing performance of the folding device 100.

[0059] In other words, the common distancing unit 140 is configured to increase or decrease the first distance, Di, and the second distance, D2, and the secondary distancing unit 150 is configured to increase or decrease the second distance, D2.

[0060] The folding device 100 comprises a folding element 130 arranged upstream of the first fold roller unit 110 with respect to the first direction, Vi, configured to initiate a folding of the at least one sheet of paper by pressing on a front side of the at least one sheet of paper in the first direction, Vi, towards the first and second rollers 112, 114, such that the at least one sheet of paper is brought into engagement with the first fold roller unit 110. The folding element 130 comprises a straight edge extending into the plane of the figure, perpendicular to the first direction, Vi. The folding element 130 may comprise a folding blade, and may be hinged or retractable, allowing it to be extended or retracted as needed during the folding process. The straight edge of the folding blade is a plain, continuous cutting edge without any serrations or teeth.

[0061] Figs. 2a-c schematically illustrate a cross-sectional view of a folding device 100 according to an exemplifying embodiment of the present invention at three stages of the folding process. It should be noted that the folding device 100 illustrated in Figs. 2a-c has several features in common with the folding device 100 shown in Fig. 1. It is hereby referred to Fig. 1 and the associated text for an increased understanding of these features of the folding device 100.

[0062] Fig. 2a illustrates a first stage / initiation of the folding process wherein (a) sheet of paper(s) 300 is about to enter the folding device 100. The folding element 130 presses upon the sheet of paper(s) 300 in a central location of the sheet of paper(s) 300, thereby initiating the folding. The folding element 130 presses in the first direction, Vi.

[0063] Fig. 2b illustrates a second stage of the folding process, wherein the common distancing unit 140 is adjusted to receive the sheet of paper(s) 300. The common distancing unit 140 may adjust the first distance, Di, either increases or decreases the first distance, Di, depending / based on at least one parameter of the sheet of paper(s) 300. The parameter of the sheet of paper(s) 300 may relate to number of papers and / or the thickness of the sheet of paper(s) 300, such that the common distancing unit 140 increases or decreases the first distance, Di, accordingly. Hence, the at least one parameter may comprise a predetermined thickness value. The parameter may be predetermined by a user and / or determined by a sensor. Hence, the folding device 100 may comprise a sensor configured to determine the at least one parameter of the at least one sheet of paper, e.g. a thickness of the at least one sheet of paper.

[0064] Figs. 2a-b illustrate how the motion of the folding element 130 is aiding in the folding process of the sheet of paper(s) 300. The folding element 130 initiates the folding process by pressing on the sheet of paper(s) 300, e.g. on a central part of the sheet of paper(s), facilitating a clean fold as the sheet of paper(s) 300 enters the space between the first roller 112 and the second roller 114. The folding element 130 presses on the sheet of paper(s) 300 such that the sheet of paper(s) reaches and engages the first fold roller unit 110.

[0065] In Fig. 2c, the folding element 130 has been moved back, allowing for the sheet of paper(s) 300 to be further conveyed forward by the first and second rollers 112, 114 and the third and fourth rollers 122, 124. The rollers 112, 114, 122, 124 convey the sheet of paper(s) 300 forwards, i.e., downstream, by rotating / spinning. The rotational direction of the rollers 112, 114, 122, 124 in this exemplifying embodiment is indicated by arrows. The rotational direction may vary depending on the intended conveying direction.

[0066] Fig. 2c illustrates the decrease of the second distance, D2. The second distance, D2, is increased or decreased by the second distancing unit 150. In Fig. 2a-c the second distancing unit 150 is illustrated as two eccentric cams, coupled to roller 122, 124 respectively. The rotation of the eccentric cams will, as illustrated in Fig. 2c, decrease the second distance, D2, by moving the rollers 122, 124.

[0067] By comparing Fig. 2b and Fig. 2c it can be understood that the common distancing unit 140 is configured to adjust the first distance, Di, and the second distance, D2. The first fold roller unit 112, 114 and the second fold roller unit 122, 124 are mounted on the common distancing unit 140 such that when the common distancing unit 140 is used to open up or close the space between the fold rollers 112, 114, 122, 124 in each fold roller unit. The common distancing unit 140 determines both the first distance, Di, and the second distance, D2. The secondary distancing unit 150 determines the second distance, D2.

[0068] The folding device 100 may comprise a folding element motor 500. The folding element / folding blade 130, may be moved using the folding element 500. The folding element motor 500 may be a any device that can provide a mechanical motion, using e.g. electricity. The folding element motor 500 is configured to drive the motion of the folding element 130 in the first direction, Vi.

[0069] It should be appreciated that, while the above example is illustrated with only a single sheet of paper 300, the same applies for using a stack of paper, regardless of the number of sheets of paper in the stack of papers.

[0070] To further exemplify the above, Figs. 2a-2c may be considered to illustrate three different positions and / or states / stages of the folding device 100. It should be realized that the folding device 100 may move between the positions dynamically and / or continuously, to adapt to papers having different thickness and different amounts of papers to be folded. Fig. 2a may be considered to illustrates a first position, wherein the folding device 100 is in a fully open position, i.e., the common distancing unit 140 and the secondary distancing unit 150 are in their respective outer positions, and have not yet been adjusted to the stack of papers to be folded. In this position the folding device 100 is awaiting the thickness of the sheet of paper(s) 300. The thickness may be measured by a sensor, or inputted by a user. Based on the thickness, the common distancing unit 140 adjust the first distance Di. During the following folding process, the common distancing 140 unit may be fixed in its position. In other words, the secondary distancing unit 150 moves depending on needed and / or desired pressure.

[0071] Fig. 2b may be considered to illustrate a second position. The second fold roller unit 120 have been adjusted by the secondary distancing unit 150 based on the inputted thickness of sheet of paper(s) 300, and / or the thickness of the folding element 130. The folding element 130 is moved, guiding / pushing the sheet of paper(s) 300 in between the first fold rollers 112, 114 and initiating the folding.

[0072] Fig. 2c illustrates the folding element 130 as it has been moved outwards, leaving the sheet of paper(s) 300 to be moved by the rotation of the fold rollers 122, 124, 112, 114. The rotation of the fold rollers 122, 124 is indicated by arrows. The second distance is further adjusted based on wanted pressure on the now folded sheet of paper(s) 300. In other words, the secondary distancing unit 150 may adjust the second distance, by increasing or decreasing the second distance, such that the pressure applied by the second fold roller unit 120 on the sheet of paper 300 is adjusted.

[0073] Figs. 3a-b schematically illustrate a cross-sectional view of an exemplifying embodiment of the folding device 100. It should be noted that the folding device 100 illustrated in Figs. 3a-b has several features in common with the folding device 100 shown in Fig. 1 and Fig. 2. It is hereby referred to Fig. 1 and 2 and the associated texts for an increased understanding of these features of the folding device 100.

[0074] In Figs. 3a-b, the folding device 100 comprises a common distancing unit 140, here shown comprising a first arm 142 and a second arm 144. On the first arm 142 the first fold roller 112 of the first fold roller unit 110 and the third fold roller 122 of the second fold roller unit 120 are arranged / mounted. On the second arm 144 the second fold roller 114 of the first fold roller unit 110 and the fourth fold roller 124 of the second fold roller unit 120 are arranged / mounted. This arrangement ensures that an opening or closing of the arms 142, 144, i.e., moving the arms 142, 144 further away or closer to each other, will increase or decrease the distance Di and the distance D2. The arms 142, 144 of the common distancing unit 140 are driven by a primary motor 172. The fold rollers 112, 114, 122, 124 comprises a conveying surface 200, wherein the conveying surface comprises rubber. The conveying surface 200 is configured to convey the at least one sheet of paper, upon rotation of the first and / or second fold roller units 110, 120. A secondary distancing unit 150 is shown comprising a rotatable eccentric cam arrangement 160 configured to adjust the second distance, D2, upon rotation of the eccentric cams. The secondary distancing unit 150 comprises a secondary motor 170 configured to rotate the rotatable eccentric cam arrangement 160. The eccentric cam arrangement 160 is illustrated comprising a first rotatable eccentric cam 162 and a second rotatable eccentric cam 164. Each of the eccentric cams 162, 164 are coupled to the third and fourth fold rollers 122, 124 of the second fold unit 120 respectively. The profile / shape of the eccentric cams 162, 164 may vary depending on the need. The secondary motor 170 drives each of the eccentric cams 162, 164, such that the secondary motor 170 induces a rotation of the rotatable eccentric cams 162, 164. The eccentric cams 162, 164 in turn induce a linear motion of the fold rollers 122, 124, causing them to move towards or away from each other, and thus decreasing or increasing the distance, D2. The secondary motor 170 may be connected to the eccentric cams 160 via a cam belt, timing belt or similar, and therethrough drive the rotation of the eccentric cams 160. The secondary motor 170 may drive the motion of both the first rotatable eccentric cam 162 and the second rotatable eccentric cam 164 simultaneously, e.g. via a cam belt, timing belt or similar.

[0075] In Figs. 3a-b, the folding device 100 comprises a spring element arrangement 190. In Fig. 3a, the spring element arrangement 190 is configured to press the first roller 112 in a second direction, V2, perpendicular to the first direction with a first force, Fi. In Fig. 3b, the folding device 100 comprises a first spring element 192 and a second spring element 194. The first spring element 192 is configured to press the first roller 112 in a second direction, V2, with a first force Fi. The second direction, V2, is indicated with an arrow and is perpendicular to the first directi on, Vi. The first direction, Vi, indicates the direction of movement of the folding element 130. The second spring element 194 is configured to press the second roller 114 in a third direction, V3, with a second force, F2. The third direction, V3, is indicated with an arrow and is perpendicular to the first direction, Vi, and opposite the second direction, V2. The first force, Fi, may have the same magnitude as the second force, F2. The secondary distancing unit 150 may be configured to adjust the second distance, D2, based on at least one of the first force, Fi, and the second force, F2.

[0076] The first and / or second spring element(s) 192, 194 may be a coil spring. The first and / or second spring element may comprise a resilient type material, having the characteristics of a coil spring.

[0077] In Fig. 3b the folding device 100 further comprises a sensor 180. The sensor 180 may e.g. be located anywhere upstream of the folding device 180 in the first direction, Vi. Preferably the sensor 180 is positioned such that a parameter related to the at least one sheet of paper may be detected, and adjusted for by the common distancing unit 140 and / or the secondary distancing unit 150, accordingly, before and / or during the at least one sheet of paper enters the first and second fold roller units 110, 120. The folding device 100 may comprise a control unit 400 configured to receive at least one of the of a detected parameter, e.g. from the sensor 180, and a predetermined parameter, e.g. from a user via a user interface. It should be noted that the control unit 400 is only schematically indicated in Fig. 3b. The control unit 400 may be configured to control at least one of the first folder roller unit 110, the second fold roller unit 120, the folding element 130, the common distancing unit 140 and the secondary distancing unit 150. The control unit 400 may be configured to control at least one of the first folder roller unit 110, the second fold roller unit 120, the folding element 130, the common distancing unit 140 and the secondary distancing unit 150 based on at least one of a detected parameter and predetermined parameter of the at least one sheet of paper. The control unit 400 may be configured control at least one of the first folder roller unit 110, the second fold roller unit 120, the folding element 130, the common distancing unit 140 and the secondary distancing unit 150 based on at least one of the first and second force(s), Fi and F2. The control unit 400 may be configured to control movement / rotation of at least one of the first folder roller unit 110, the second fold roller unit 120, the folding element 130, the common distancing unit 140 and the secondary distancing unit 150. The control unit 400 may be e.g. processing circuitry or a computer. It is to be understood that the control unit 400 may be configured to control any motor 170, 172, 500 of the folding device 100.

[0078] The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, the different parts of the folding device 100 may have different shapes, dimensions and / or sizes than those depicted / described.

Claims

CLAIMS1. A folding device (100) for folding at least one sheet of paper (300), comprising a first fold roller unit (110), comprising a first roller (112) and a second roller(114) separated by a first distance, Di, configured to convey the at least one sheet of paper in a first direction, Vi, a second fold roller unit (120), arranged downstream of the first fold roller unit with respect to the first direction, Vi, comprising a third roller (122) and a fourth roller (124) separated by a second distance, D2, configured to convey the at least one sheet of paper in the first direction, Vi, a folding element (130), arranged upstream of the first fold roller unit with respect to the first direction, Vi, configured to initiate a folding of the at least one sheet of paper by pressing on a front side of the at least one sheet of paper in the first direction, Vi, to the first and second rollers, wherein the first fold roller unit is configured to engage a back side of the at least one sheet of paper and transport the at least one sheet of paper to the third and fourth roller to allow the second fold roller unit to engage the back side of the at least one sheet of paper, a common distancing unit (140), wherein the first fold roller unit and the second fold roller unit are mounted on the common distancing unit, wherein the common distancing unit is configured to adjust the first distance, Di, and the second distance, D2, and a secondary distancing unit (150) configured to adjust the second distance, D2, independently of the common distancing unit.

2. The folding device (100) according to claim 1, wherein the folding device is configured to, by the common distancing unit, adjust the first distance, Di, and the second distance, D2, based on a thickness, T, of the at least one sheet of paper during a first folding stage, and is configured to, by the secondary distancing unit, adjust the second distance, D2, during a second folding stage, wherein the first folding stage comprises conveying and folding the at least one paper by the first fold roller unit, and the second folding stage comprises conveying and folding the at least one paper by the second fold roller unit3. The folding device (100) according to claim 1 or 2, wherein the secondary distancing unit (150) is configured to adjust the second distance, D2, based on the first distance, Di.

4. The folding device (100) according to any one of the previous claims, wherein the folding device is configured to, by the secondary distancing unit (150), adjust the second distance, D2, after the at least one sheet of paper (300) is received by the second fold roller unit (120).

5. The folding device (100) according any one of the previous claims, wherein at least one of the first (112), second (114), third (122) and fourth (124) roller comprises a conveying surface (200) comprising rubber.

6. The folding device (100) according to any one of the previous claims, wherein the secondary distancing unit (150) comprises a rotatable eccentric cam arrangement (160) configured to adjust the second distance, D2, upon rotation of the rotatable eccentric cam arrangement, and a secondary motor (170) configured to rotate the rotatable eccentric cam arrangement.

7. The folding device (100) according to claim 6, wherein the rotatable eccentric cam arrangement (160) comprises a first rotatable eccentric cam (162) configured to adjust the second distance, D2, upon rotation of the first rotatable eccentric cam, and a second rotatable eccentric cam (164) configured to adjust the second distance, D2, upon rotation of the second rotatable eccentric cam.

8. The folding device (100) according to any one of the previous claims, wherein the common distancing unit comprises a first arm (142), wherein the first roller (112) and third roller (122) are mounted on the first arm, a second arm (144), wherein the second roller (114) and fourth roller (124) are mounted on the second arm, and a primary motor (172) configured to move the first and second arms relative18 each other, such that both the first distance, Di, and the second distance, D2, are adjusted.

9. The folding device (100) according to any one of the previous claims, wherein the folding device comprises at least one sensor (180) configured to determine at least one of a thickness, T, of the at least one sheet of paper (300), the number of sheets of the at least one sheet of paper, and a characteristic of the at least one sheet of paper.

10. The folding device (100) according to any one of the previous claims, wherein the folding element (130) comprises a folding blade (132) comprising a straight edge (134).

11. The folding device (100) according to any one of the previous claims, wherein the first fold roller unit (110) comprises a spring element arrangement (190) configured to press at least one of the first roller (112) and the second roller (114) in a second direction, V2, perpendicular to the first direction, Vi, with a first force, Fi.

12. The folding device (100) according to claim 11, wherein the spring element arrangement comprises a first spring element (192) configured to press the first roller (112) in the second direction, V2, perpendicular to the first direction, Vi, with a first force, Fi, and a second spring element (194) configured to press the second roller (114) in a third direction, V3, perpendicular to the first direction, Vi, and opposite the second direction, V2, with a second force, F2.

13. The folding device (100) according to claim 12, wherein the secondary distancing unit (150) is configured to adjust the second distance, D2, based on at least one of the first force, Fi, and the second force, F2.

14. The folding device (100) according to any one of the previous claims, further comprising a control unit configured to control the common distancing unit (140) and the secondary distancing unit (150).

15. A method for controlling folding at least one sheet of paper (300), using a folding device (100) according to any one of claims 1-14, the method comprising receiving a thickness, T, of at least one sheet of paper, adjusting the first distance, Di, and the second distance, D2, using the common19 distancing unit (140) based on the received thickness, T, of the at least one sheet of paper, initiating folding of the at least one sheet of paper by pressing on a front side of the at least one sheet of paper in the first direction, Vi, to a first (112) and second (114) roller, using the folding element (130), and conveying and folding the at least one sheet of paper by the first fold roller unit(110) to the second fold roller unit (120), initiating adjusting of the second distance, D2, using the secondary distancing unit (150), and conveying and folding the at least one sheet of paper by the second fold roller unit.

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