EP0871928A2

EP0871928A2 - Arrangement for turning or displacing a web of continuous recording material

Info

Publication number: EP0871928A2
Application number: EP96932434A
Authority: EP
Inventors: Günther GASSNER
Original assignee: Oce Printing Systems GmbH and Co KG
Current assignee: Canon Production Printing Germany GmbH and Co KG
Priority date: 1995-10-27
Filing date: 1996-08-02
Publication date: 1998-10-21
Anticipated expiration: 2016-08-02
Also published as: US6027003A; DE29622735U1; WO1997018951A2; WO1997018951A3; EP0871928B1; DE59608281D1

Abstract

The invention concerns an arrangement for turning and displacing a web (8) of continuous recording material, in particular a web of paper in an electrographic printer. The web (8) is fed along a first conveying path (30) out of a conveying direction (32) by a web-feeding device (34) and, after passing around a deflection device (40) disposed below the web-feed device (34) and after the latter, viewed in the conveying direction, is displaced via a web-discharge device (44) by at least one web width. The first edge (38) of the fed web (8) facing the web-discharge device (44) lies loosely on a first guide surface (42) of the deflection device (40). The invention further concerns a displacement arrangement which displaces the web (8) by one web width without turning it.

Description

description

Means for turning or moving a web of continuous recording material

The invention relates to a device for turning and moving a web of endless recording material, in particular a paper web in an electrographic printer. The invention further relates to a device in which the web of continuous recording material is only offset in parallel.

Devices of this type are important components of an electrographic printing device for printing on tape-shaped recording media of different bandwidth. Such a printing device is described, for example, in WO / 94 27193. The printing device has an electrographically operating intermediate carrier, for example a photoconductor drum, with a usable width corresponding to twice the width format of a standard form, for example DIN A4 or letter-size format. The other units, such as the fixing station, the developer station, the cleaning station, etc. are also designed for this usable width.

Various modes of operation are possible with this known printing device. In single-color duplex operation, the web of endless recording material is turned over during transport through the printing device, so that two web sections result: in a first web section the front of the web faces the transfer location of a printing unit, while in a second web section the The back of the web is printed simultaneously at the same transfer location. By using different colored color particles in different developer units of the printing unit, a two-color duplex operation is also possible. In another operating mode, the two-color simplex mode, the web is transported by at least one during transport of the printing device Web width offset parallel. The offset web sections are guided past the transfer point in the side-by-side position. The first time the web passes the transfer location, image and text elements are printed with a first color; the second time the web passes by with a lateral offset, image and text elements are printed with the second color.

For the sake of completeness, reference is made to simplex operation and parallel simplex operation. In the first-mentioned simplex operation, a recording medium with up to twice the width of an A4 sheet or a sheet with letter-size format is printed in a conventional manner. In parallel simplex operation, two separate tracks, e.g. each with a width in accordance with DIN A4 or letter-size format, guided and printed in the side-by-side position through the printing device.

When printing on a single web, which is offset in parallel in the printer or offset in parallel and additionally turned and fed to the transfer printing unit of the printing unit and printed again, it must be ensured that the parallel offset or the parallel offset with simultaneous turning is trouble-free and with high precision expires. When using a device for turning and / or moving a web in a high-performance printer that achieves web transport speeds in the range of 0.1 to 2.5 m / s, measures must be taken to ensure that the web runs quickly even when using allow foldable endless material with folds.

From patent application 94 112 973.6, a turning device for tape-shaped recording media is known, in which deflection elements for deflecting the web are arranged in a W-shape. The web is fed taut through the turning device and is in close contact with the deflection units. From another German patent application P 44 35 756.7, a turning device for tape-shaped recording media is known, the deflection elements of which form two turning triangles. The turning triangles are rotated relative to each other by an expansion angle, so that the entire turning device takes up little space.

It is an object of the invention to provide a device for moving or for moving and turning a web, which is simply constructed and ensures trouble-free operation.

This object is achieved for a device for turning and moving a web of endless recording material by the features of claim 1. For a device exclusively for moving a web without turning it, this object is achieved by the features of claim 12. Advantageous developments of the invention are specified in the dependent claims.

According to the first aspect of the invention, in which the web is used and displaced, this web is loosely guided around a deflecting device, the first edge being fed obliquely downward from above to the deflecting device and coming obliquely upward there from below is discharged again. The edge lies against the first guide surface of the deflection device, so that a natural loop formation is formed from the web feed device to the web delivery device. Since this first edge lies loosely against the first guide surface, the web loop can be in the vertical direction

Execute deflection movements and thus compensate for fluctuations in the transport speed in the region of the deflection device. Such fluctuations can arise, for example, from changes in the friction conditions or from wrinkles. The invention is suitable both for sheets of continuous material without transverse folds and for sheets with folds (fan-fold sheets). In the invention, the web surface comes into frictional contact with only a few elements. This reduces the risk of web congestion as a result of different friction conditions or damage to the web. The surfaces of the mechanical guides in contact with the web can be provided with very low-friction surfaces or can be made wear-resistant by surface treatment. This further increases the operational safety of the device.

In practice it has been shown that web speeds of up to 2.5 m / s and higher can be mastered and the requirements for use in high-performance printers are met. The web run is particularly stable in the upper region of the web speed.

The first guide surface is preferably convex. It is therefore adapted to the curvature of the geometry of the web loop which is self-forming due to the weight of the web and its elasticity and supports the natural formation of the loop.

An embodiment of the invention is characterized in that the elongate body of the deflection device has a second guide surface in its upper region, which guides and holds down the second edge of the web opposite the first edge when the web rises around the body during circulation and a exceeds a predetermined height. These measures limit the vertical deflection movement of the loop on the loop base to a predetermined level. If the uniformity of the web transport is disturbed as a result of a malfunction, for example due to the web folding at the fold points of the fan-fold web, the web loop is shortened, which is manifested in a rising of the web on the first guide surface. The upper, second edge of the track comes to rest against the second guide surface from a predetermined height, whereupon the tensile stress at the second edge of the Web is enlarged and the web tightens and unfolds. Disruptions in the passage of the web are thus automatically compensated for.

According to a further exemplary embodiment of the invention, the height of the first and second guide surfaces can be adjusted. In this way, on the one hand, the deflection device can be adapted to different widths of the web. On the other hand, the height adjustment enables adaptation to the length of the web loop from the web feed device to the web delivery device. This web loop also serves as a web store, the length of which is set as a function of the length format used for the web of the web and is specified by the printer controller or the operating personnel.

According to a further aspect of the invention, a device for displacing a web of endless recording material is provided with the features of claim 12. With this facility, the web is not turned. The device is designed so that the web forms a loosely hanging web loop. The web is guided in such a way that the first edge of the supplied web facing the web delivery device is discharged approximately in the transport direction along a second transport path on the side facing away from the web supply device. The upper side of the track on the second transport track and the top of the track on the first transport track match. This device is therefore used for two-color simplex operation.

The solution to the stated problem according to this aspect of the invention is surprisingly simple and the web loop which is naturally formed due to the weight of the web enables the offset by at least one web width. Due to the weight of the web, the shape of the web loop remains stable even at high transport speeds. It 97/18951 PO7DE96 / 01449

6 sheets with folds as well as smooth sheets can be transported and moved.

In a preferred embodiment of the invention, the web removal device includes a guide element, which is arranged at least approximately in a horizontal plane and has a guide surface over which the web is guided after passing through the web loop, the longitudinal axis of the guide surface having the length projected into the horizontal plane - Axis of the web feed device includes an angle in the range from 15 ° to 25 °, preferably 20 °. Due to its oblique arrangement, this guide element enables the natural loop shape to be retained and small radii of curvature to be avoided when deflecting into the parallel offset transport path, which can cause wrinkling. When using folded recording material, the guide element prevents the web from buckling at the folds.

In order to avoid wrinkling or wrinkling in the recording material, the web leaving the guide elements is fed directly from below to a deflecting element which deflects the web in the direction of the web loop. The deflecting element has a longitudinal axis which is at least approximately parallel to the longitudinal issue of the web feed device. The deflecting element prevents a curvature of the web, which can result from the web being offset by at least one web width.

In one embodiment, the guide element and preferably also the deflecting element on the side facing the web feed device can have a stop against which the edge of the web lies. This results in defined edge positions of the web and precise guidance.

Exemplary embodiments of the invention are explained below with reference to the drawings. Intestine show: FIG. 1 shows a high-performance printer in the duplex mode with a turning device,

FIG. 2 shows the high-performance printer in the two-color simplex printing mode with a displacement device,

FIG. 3 shows a schematic illustration of a turning device according to the invention,

FIG. 4 shows the turning device according to FIG. 3 in a top view,

FIG. 5 shows several exemplary embodiments for a deflection device,

FIG. 6 an embodiment of the web guiding device,

FIG. 7 a guide element for feeding a first web section during the insertion operation,

FIG. 8 shows an exemplary embodiment for a displacement device,

9 shows the displacement device according to FIG. 8 in a top view, and

FIG. 10 variants of the paper feed for a displacement device according to the invention.

Details of the invention are described below using a high-performance printer which operates in the operating modes already described. FIG. 1 shows the high-performance printer in duplex mode, in which a single web 8 is printed on its front and back. The printer has a transport device 10 which, arranged near a printing unit 12, requests the web 8 through the printing unit 12, in which a charge image applied to a photoconductor drum 14 and colored with toner is transferred to the web 8 by means of a corona device (not shown). Subsequently, the web 8 is fed to a fixing station 16, in which the still smearable toner image is connected to the carrier material in a wipe-proof manner with the aid of pressure and temperature. The web 8 is fed to the printing unit 12 with a first web section A starting from a first stack 22. After printing and fixing, the web 8 is fed to a turning device 18 via a deflection unit 20. This turning device 18 turns the web 8 and laterally displaces it by at least one web width, so that the back of the web 8 can now be fed as web section B to the printing unit 12 for printing. The printed web section B is also fed to the fixing station 16, which connects the printed image on the back of the web 8 to the surface of the carrier material in a wipe-proof manner. The web 8 is then stacked on a stack 24.

The transport unit 10, the printing unit 12, the photoconductor drum 14 and the fixing station 16 have a working width of at least twice the web width of the web 8. In the present case, the printer is equipped with an photoconductor drum 14. Instead of the photoconductor drum 14, a band-shaped intermediate carrier, e.g. em OPC tape or a magneto-style arrangement can be used. Other units for the electrographic printing process are grouped around the photoconductor drum 14. These units and the structure of the entire printer smd are described in more detail in German patent application P 44 35 756.7, the disclosure content of which is included in the present application.

FIG. 2 shows the printer in two-color simplex mode, in which the front side of the web 8 has a first color and a first color when it passes the printing unit 12 for the first time subsequent second passage past the printing unit 12 is printed with a second color. Since the front side of the web 8 is to be printed in each of the two revolutions, an offset device 26 is provided at the separation point between the web sections A and B, which offset the web 8 in parallel by at least one web width, but does not turn it.

In Figures 1 and 2, the web 8 is in stack form. For high performance printers, web 8 is often wound on a roll. Both folded webs (fan-fold webs) and smooth webs without folds can be processed.

FIG. 3 schematically shows an exemplary embodiment of the turning device 18 for the printer, which works in duplex mode. The web 8 is fed along a first transport path 30 (details of this transport path 30 have been omitted in the figures for reasons of better clarity) from a transport direction according to the arrow 32 via a web feed device 34. In the example shown here, this web feed device 34 is realized by a roller. In practice, the web feed device 34 can contain several rollers and deflection units in order to realize a special web feed depending on the geometric conditions of the printer. The web 8 has a front face marked by crosses 35 and a rear face marked by circles 36.

The web 8 is loosely guided around a deflection device 40 arranged vertically below the web feed 34, so that its edge 38 lies loosely against a guide surface 42 of the deflection device 40. The front of the web 8 faces this guide surface 42. The web 8 is guided obliquely upwards to the web delivery device 44 and is deflected there into a second transport path 46 which is arranged parallel to the first transport path 30. The edge 38 faces the web feed device 34. The direction of transport (arrow 48) of the transport path 46 coincides approximately with the transport direction (arrow 32) of the transport path 30. Both transport tracks 30, 46 require the track 8 downstream in the direction of the printing unit of the printer.

The axes 48, 50 of the web delivery device 44 and of the web feed device 34 are aligned parallel to one another. The longitudinal axis 52 of the deflection device 40 is arranged vertically.

As can be seen in FIG. 3, under the effect of the weight of the web 8, a natural, loose web loop 54 is formed, the shape of which remains relatively stable even during the web transport at high speed. This is because the inner edge 38 is guided on the guide surface 42, which has a convex curvature. This arch supports the formation of a loop, even if the web has 8 folds.

The formation of a stable web loop 54 is further supported by a web guide device 56, which has a concavely curved guide plate 58 and a movable support element 60, which is fixed at each end. The guide plate 58 is arranged just below the web feed device 34 and has a width at least equal to the web width of the web 8

Support element 60 can be formed by a number of spiral springs arranged next to one another (not shown). The support element 60 rests with friction on the front of the web 8 and moves it against the guide plate 58. This counteracts any bulging of the recording material, which can occur in particular at fold points of the web 8, and the web run in the initial region of the web loop 54 is calmed down.

FIG. 4 shows a plan view of the turning device 18 according to FIG. 3. The deflection device 40 is cylindrical in this case and can be realized, for example, through a tube. s sem. However, other shapes for the deflecting device are also conceivable; it is only essential that the guide surface 42 is convexly curved in order to support the formation of a round, natural web loop 54. The web delivery device 44 has a stop 62 on the side facing the web feed device 34, against which the edge 38 of the web 8 bears. In this way, a precise alignment of the web 8 is possible for its further transport.

FIG. 5 shows further embodiments a, b, c of the deflection device 40. The embodiment a has a lower cylindrical section 64, which provides the curved guide surface 42. In the upper area of the deflection device 40, two arms 66, 68 are flanged, which extend at an angle of approximately 45 ° to the longitudinal axis of the deflection device 40. These arms 66, 68 have the function of preventing the web 8 from rising. Such an ascent can occur when the friction on the guide surface 42 fluctuates or when the web 8 buckles on folds. The arms 66, 68 form second guide surfaces for the upper edge of the web 8 and stabilize the shape of the web loop 54.

The cylindrical section 64 can be adjusted in height relative to a base 70, as indicated by the double arrow 72.

The height adjustment can take place depending on the required length of the web loop for a web storage function and depending on the length of the form of web 8.

The exemplary embodiment b in FIG. 5 shows a composite rotational body, the rotating surface of which is an ellipse 74 and a rectangle 76.

The exemplary embodiment c in FIG. 5 shows a composition of a truncated cone 78 and a cylinder 80

Truncated cone 78 has the same function as that of arms 66, 68 according to exemplary embodiment a, its upper guide surface being enlarged.

FIG. 6 shows an exemplary embodiment of the web guiding device 56. On the side opposite the guiding plate 58, an end cloth 84 is fastened movably with one end 84. The other end 86 lies on the surface of the web 8 and thus soothes transport movements of the web 8. Instead of the cloth cloth 82, a felt cloth or a rubber blanket can also be used.

A guide element 90 is shown in FIG. This guide element 90 is arranged radially at a distance from the deflection device 40 below the web feed device 34. This guide element 90 has an approximately upright, concavely curved guide surface 92 with a support edge 94 projecting approximately vertically in the lower region. The guide element 90 serves to guide an initial section of the web 8 around the deflection device 40 when it is inserted. In the inserting operation, the initial section is fed via the web feed device 34 and reaches with its edge 38 the contact edge 94, along which it moves as web 8 is further challenged. The surface of the web 8 lies against the curved guide surface 92, so that a curvature of the web 8 arises and its front edge is guided past the deflection device 40. An operator can now grasp this front edge of the web 8 and insert the web 8 into the web delivery device 44 while forming the web loop 54. The guide element 90 avoids a web jam during the insertion operation and makes it easier for an operator to embroider.

FIG. 8 shows the displacement device 26 for displacing a web 8 by at least one web width. The same, already described parts smd the same. The web 8 is fed along the first transport path 30 from the transport device 32 through the web feed device 34. The The transport roller 34 has Bahnzufuhrvomchtung backpressure ^¬ rolls 96, prevent the em upgrade of the web. 8 The web 8 with its outer edge 38 is fed to a guide element 98 with the formation of the web loop 54 so that the edge 38 faces the web feed device 34. The web 8 slides over a guide surface 100 of the guide element 98, which is convexly curved. In the present case, the guide element 98 has a cylindrical surface. Immediately after the deflection on the guide element 98, the web 8 is fed to a deflection element 102. The deflecting element

102 has an axis 104 which is arranged parallel to the axis 50 of the web feed device 34.

The guide element 98 can be pivoted in a horizontal plane by an angle according to the double arrow 106. The oblique arrangement of the guide element 98 keeps the shape of the web loop 54 stable. The arrangement of the deflecting element 102 m near the guide element 98 results in a deflection of the web 8 with a relatively large radius of curvature, so that the web 8 is not creased or wrinkled. The web 8 is then guided to any further elements of the web delivery device 44.

The deflecting element 102 has on its side facing the web feed device 34 the stop 62 which serves for precise edge guidance. Likewise, the guide element 98 can be provided with a corresponding stop on its right side. The stop 62 can be designed so that it is displaceable in the direction of the axis 104 in order to be adapted to the width of the web.

FIG. 9 shows a top view of the displacement device 26 according to FIG. 8. The axes 99, 104 of the guide element 98 or of the deflecting element 102 projected in a horizontal plane form an angle of w = 20 °. The guide element 98 in FIG Deflection element 102 are pivoted so that its axis 99 lies with the axis 104 in a vertical plane. In this state, the unit formed from guide element 98 and deflecting element 102 forms a guide device for guiding the web 8. This unit can be used in a turning device 18 according to FIG. 3 as part of the web delivery device 44 shown there. FIG. 9 also shows a top view of the web guiding device 56, which, as already mentioned, serves to calm the web run and to form the web loop 54.

FIG. 10 shows different variants of the web feed and the web removal for the transfer device 26. The web 8 arriving from the direction according to arrow 32 along the transport web 30 is further requested after passing through the web loop 54 via a further deflection roller 106 in the same transport direction (arrow 48). The deflection roller 106 is part of the web removal device 44 with the further components guide element 98 and deflection element 102. Further variants of the web supply are shown in dashed lines in FIG. A web 8 fed from the right according to arrow 108 or a web 8 fed from above (arrow 110) is output to the left via the deflection roller 106 according to arrow 112. As can be seen, the transport directions are generally determined in such a way that the web 8 is requested downstream in the direction of the printing unit.

Reference should also be made to the adjustability of the deflecting element 102. In order to facilitate the insertion process for the web 8, the deflecting element 102 can be pivoted vertically upward about an axis of rotation 113 in the direction of the arrow 114. The operator can then guide the initial section of the web 8 around the deflection roller 106 in the insertion mode and then pivot the deflection element 102 back into the position shown in FIG. Components of the turning device 18 and the displacing device 26 shown in FIGS. 3 to 10 can be combined with one another. In the embodiment according to FIG. 10, a deflection device of the type of the deflection device 40 shown in FIG. 3 can be included. The web loop 54 is then placed around the deflection device 40, the guide element 98 is pivoted back to an angle w = 0 and the web is guided between the guide element 98 and the deflection element 102. Such an arrangement then has the function of a turning device. Depending on the desired mode of operation, duplex unit or two-color simplex operation, the device according to FIG. 10 can be converted into a turning device or a transfer device in a relatively short time.

Claims

claims

1. Device for turning and moving a web (8) made of endless recording material, in particular a paper web in an electrographic printer, with a web feed device feeding the web (8) along a first transport path (30) from a transport direction (32) (34), and with the web (8) after being rotated by a deflection device (40) arranged below and in the transport direction after the web feed device (34), the deflecting device (44) discharging the web delivery device is offset by at least one web width Above the deflection device (40) and next to the web feed device (34), the first edge (38) of the fed web (8) facing the web delivery device (44) loosely attached to a first guide surface (42) of the deflection device (40) lies, and the web with this first edge (38) is guided obliquely upwards to the web delivery device (44) and on the side facing the web supply device (34) along a second transport path hn (46) is removed approximately in the transport direction (48).

2. Device according to claim 1, characterized in that the deflection device (40) has an elongated body, the longitudinal axis (52) of which extends approximately vertically, and in that the first guide surface (42) is convexly curved.

3. Device according to claim 2, characterized in that the body has a cylindrical lower portion.

4. Device according to one of the preceding claims, characterized in that the body in its upper region has a second guide surface which guides and holds down the second edge of the web (8) opposite the first edge (38) when the web (8) rises high around the body and exceeds a predetermined height.

Device according to claim 4, characterized in that the second guiding surface is formed by spread arms (66, 68) of the Y type, that the arms (66, 68) lie within a plane which is at least approximately parallel to the path section shortly after the feeding by the web feed device (34).

Device according to claim 5, characterized in that the arms are spread apart from the longitudinal axis of the body at an angle of 30 ° to 60 °, preferably 45 °.

Device according to claim 4, characterized in that the body is constructed as a rotating body (74, 76; 78, 80)

8. Device according to claim 7, characterized in that the rotary surface of the rotary body is Y-shaped.

9. Device according to claim 4, characterized in that the body has at least in its upper part the shape of a truncated cone upside down.

10. Device according to one of the preceding claims, characterized in that the first (42) and the second guide surface adjustable in height smd.

11. Device according to claim 10, characterized in that the height adjustment is dependent on the required length of the web loop (54) for a web store.

12. A device for moving a web (8) made of endless recording material, in particular a paper web in an electrographic printer, with a web feed device (34) feeding the web (8) along a first transport path (30) from a transport direction (32), and with a web delivery device (44) which leads the web (8) after passing through a loosely hanging web loop (54) offset at least by one web width, which is arranged above the web loop (54) and next to the web feed device (34), the web delivery device (44) removes the web with a first edge (38) of the supplied web (8) facing the web delivery device (44) on the side facing away from the web feed device (34) along a second transport path (46) approximately in the transport direction (48) .

13. The device according to claim 12, characterized in that the web removal device (44) em at least approximately in a horizontal plane arranged guide element (98) with a guide surface (100) via which the web (8) after passing through the web loop (54) is guided, and that the longitudinal axis (99) of the guide surface (100) with the longitudinal axis (104) of the web feed device (44) projected into the horizontal plane includes an angle (w) in the range from 15 ° to 45 °, preferably 20 ° .

14. Device according to claim 13, characterized in that the guide surface (100) is convex.

15. Device according to one of the preceding claims 12 to 14, characterized in that the web delivery device (44) contains a deflecting element (102) to which the web (8) guided via the guide element (98) is fed directly, and that Track (8) from the direction of the tion element (98) coming to the deflecting element (102) from below and deflected in the transport direction (46).

16. Device according to emem of claims 13 to 15, characterized in that daε guide element (98) from a first position in which the guide surface (100) is arranged parallel to the axis (104) of the deflecting element (102) by the angle ( w) is pivotable and can be fixed in this pivoted position.

17. Device according to one of the preceding claims, characterized in that the guide element (98) and preferably also the deflection element (102) on the side facing the web feed device (34) each have a stop (62) on which the edge ( 38) of the web (8).

18. Device according to emem of the preceding claims 1 to 17, characterized in that the web feed device

(34) contains a transport roller and at least one counter-pressure roller (96), between which the web (8) is fed.

19. Device according to one of the preceding claims, characterized in that a web guiding device (56) is arranged below the web feed device (34), which enables a calm and loose feeding of the web (8).

20. Device according to claim 19, characterized in that the web guiding device (56) has a preferably concave curved supporting surface (58) with a width which corresponds to at least the width of the web (8).

21. Device according to claim 18 or 19, characterized gekenn¬ characterized in that the web guiding device (54) em movably This support element (60) contains, which moves the front of the web (8) with friction against the support surface (58).

22. The device according to claim 21, characterized in that the support element (60) is formed by a number of helical springs arranged side by side.

23. The device according to claim 21, characterized in that the support element (60) by emen felt cloth or a

Cloth rag (86) is formed.

24. Device according to one of the preceding claims, characterized in that a guide element (90) is arranged below the web feed device (34) which preferably guides the front section of the web (8) when it is fed in a predetermined direction ¬ in the direction of an operator.

25. The device according to claim 24, characterized in that the guide element (90) has a curved contact surface (92) for the first section of the web and eme lower contact edge (94) for an edge of the web (8).

26. Device according to claim 25, characterized in that the support surface (92) consists of a material which does not become electrostatically charged when the web (8) is moved.