EP0934223B1 - Device for de-cambering a supporting material - Google Patents

Description

The present invention relates to a decurling unit according to the preamble of claim 1 for decurling carrier material.

With high-performance electrophotographic printers bulges the paper used as a carrier material when fixing the toner due to the influence of pressure and heat concave to convex. This curl 5 depends on the paper quality, which is primarily due to Thickness, moisture and the manufacturer is determined as well on the number of fixations, i.e. from the chosen one Print mode. The first time it is fixed, the paper becomes disproportionate extracted a lot of moisture. Therefore join her in contrast to the second, third, etc fixation one particularly strong curvature of the paper. With a newer one Printing system with two printing units e.g. is the number of Fixations depending on the print mode, such as simplex, duplex, Spot color simplex, spot color duplex printing.

The paper quality can be considered within a paper stack are assumed to be constant, but not the number of Fixations per sheet or per page. When using Roll paper that e.g. with automatic feeding into one Cut sheet printer at the printer entrance cut to size , the curvature that changes with the roll diameter must of the fed paper are taken into account.

So are de-arching units (also in German Known as "Decurler"), where the paper with only a direction of deformation, i.e. concave or convex curvature, can be smoothed. Such a known decurling unit bends the paper against the direction of deformation. at undeformed, i.e. straight paper, this decurling unit may not be used, otherwise it would be in it be deformed. Therefore, paper transport is smooth Paper with such a decurling unit is not possible.

From US-A 4 360 356 a decurling device is known the either concave or convex paper smoothes or can be passed through smooth paper, without bending the paper. The vaulting facility has two parallel to each other running strips that are transverse to the direction of transport of the paper, and two parallel to the two bars extending rollers, which in Direction of transport seen immediately after the two Strips are arranged. The strips and the rollers are on attached to a common swivel with which together around a transverse to the direction of transport Axis can be pivoted. The paper will be between passed through the two strips and the two rollers, one bar with diametrically opposite arranged roller forms a decurling unit with which convex or concave paper can be smoothed. The strips and the rollers are used to smooth the paper pivoted together about the axis so that the decurling device continuous paper on one of the two Last as well as the diametrically opposed Roller is under tension and is thereby arched. If the decurling device runs through smooth paper, the pivoting device is placed so that the paper runs between the strips and the rollers without to touch them.

A decurling unit is known from US Pat. No. 5,565,971. with the optionally concave or convex arched carrier material can be smoothed. The decurling unit has to this Purpose a transverse to the direction of transport of the carrier material fixed first roller and a parallel to this running, driven, rubberized second roller, whereby both rollers are attached to a common base plate are. For smoothing a concavely curved substrate with the help of a swivel device against a conveyor belt the first Roller pressed. This forms between the Transport belt and the roller an elastic Transport gap through which the substrate to be smoothed is transported. That from the elastic The transport gap emerging from the arched carrier material is on passed the second roller without touching it. Around to debulk a convexly curved carrier material is used Help one also on the swivel device provided the baffle on the backing rotating second roller passed, causing the Backing material is bent. The one with the first roller cooperating conveyor belt is in this position Swivel device deactivated, so that the carrier material is guided past the roller, but without the Conveyor belt and the first roller to be bent. at this known decurling unit now exists Problem that they are only convex or concave Carrier material can be run through. smooth Backing material that is not deformed is opposed inadvertently by the decurling unit deformed so that the decurling unit for the Use of undeformed carrier material is not suitable.

The invention is therefore based on the object of a decurling unit To provide a smoothing of the Backing material regardless of the direction of deformation allows. In particular, in addition to carrier material with a concave or a convex deformation also carrier material passed through the decurling unit without deformation can be.

This task is at the beginning of a de-arching unit mentioned type by the characterizing features of the claim 1 solved. Advantageous further developments result from the Dependent claims.

The element in the decurling unit according to the invention is to remove convexity with the element for Eliminating concavity so functionally coupled that on the one hand with an increase in the effect of the element Eliminating convexity a decrease in the effect of the Elements to remove concavity and on the other hand a decrease in the effectiveness of the elimination element from convexity to an increase in the effect of the element Elimination of concavity occurs. This enables one continuous or graded adjustment of the decurling unit between two extreme settings for elimination extreme concavity or extreme convexity.

In a special embodiment, the element is to be eliminated of concavity a wave of dewatering with itself extending perpendicular to the direction of transport of the carrier material Axis of rotation, with the de-arching shaft in one or more arranged parallel to each other, driving them by static friction stretchable de-belting that is submersible between a drive roller and a deflection roller for the or the de-belting in the transport direction of the Carrier material are stretched, the axes of rotation of the Drive roller and the deflection roller also perpendicular to Extend the direction of transport of the carrier material, so that the or Deconvolution belt in convex shape on the decurling shaft is or are concerned. The concavity is removed by the concave arched substrate to be smoothed between the de-tearing belt and the one in it with a suitable one Immersion depth t immersed wave of decurling and between the belt and shaft convex, i.e. opposite, is bent.

The element is useful for eliminating convexity one concave in the transport direction of the carrier material shaped outlet contour that is in the paper path at an angle is pivotable. The convex paper is made by the concave curved outlet contour, by a suitable swivel angle γ is swung out in the opposite direction deformed, whereby a smoothing is achieved.

In a particularly advantageous embodiment, these are Element for removing concavity and the element for Elimination of convexity rigidly connected by a linkage and pivotable together about a common axis of rotation A.

This allows a mechanical control of the At the same time, the depth of immersion t of the decurling shaft in the decurling belt and the swivel angle γ the Set the outlet contour. When the boom swings the immersion depth t and the Swivel angle γ too, which causes the concavity-de-arching is increased and the convexity-de-arching is reduced. If the boom swings in the opposite direction, take it the immersion depth t and the swivel angle γ, whereby the concavity-de-bulge decreases and the convexity-de-bulge is increased.

The linkage is expediently pivoted through a tooth segment rigidly connected to the linkage via a Pinion of an actuator. This configuration is special simple and enables a continuous curvature of the carrier material by a corresponding one-time rotation of the tooth segment.

This enables uncomplicated automatic readjustment the decurling unit depending on one or one Combination of the parameters "initial warpage of the Substrate "," selected print mode "or" quality of the substrate " direct control of the servomotor.

Especially when using rolled paper, that will be cut at the printer entrance becomes the diameter of the coil and based on the detected diameter the servomotor of the decurling unit is controlled. In this way, the decoiling device according to the invention the curvature of the rolled paper on Printer input constantly adjusted.

Fig. 1

eine schematische Darstellung des Entwölbungsvorgangs zeigt;

Fig. 2

eine Schnittansicht einer bevorzugten erfindungsgemäßen Entwölbungseinheit in einer ersten Einstellung zeigt;

Fig. 3

eine Schnittansicht der bevorzugten erfindungsgemäßen Entwölbungseinheit in einer zweiten Einstellung zeigt;

Fig. 4

einen Drucker mit integrierten Entwölbungseinheiten zeigt; und

Fig. 5

den Drucker nach Fig. 4 mit einer speziellen Rollenpapierzufuhr zeigt.

Further advantages, features and possible applications of the invention result from the following description of a preferred embodiment of the invention with reference to the accompanying drawing, wherein

Fig. 1

shows a schematic representation of the de-arching process;

Fig. 2

a sectional view of a preferred decurling unit according to the invention in a first setting;

Fig. 3

a sectional view of the preferred decurling unit according to the invention in a second setting;

Fig. 4

shows a printer with integrated decurling units; and

Fig. 5

shows the printer of Fig. 4 with a special roll paper feed.

Fig. 1 shows schematically the smoothing process for concave corrugated paper a and convex curved paper b that made up a fixing station F is ejected. The deburring unit E converts the concave or convex paper to smooth Paper c around.

Fig. 2 shows a sectional view of a preferred embodiment the decurling unit in a first setting. A drive roller 2 and a guide roller 6 with each fixed axes perpendicular to the transport direction of the Paper (in the drawing plane) tension one or more parallel to each other arranged de-warping belts 4 consist of a rubber-like stretchable material. A Vaulting shaft 8, the axis of rotation of which around a fixed one Axis A pivotable rod 10 is fixed, dives in or the tensioned de-belt 4 with a Immersion depth t1. This arrangement forms an element for Eliminating concavity. One along the R1 direction introduced concave (downward) curved sheet of paper is on its leading edge by the rubber-like dew point belt 4 and the one attached to it and driven by it Detonation wave 8 detected and drawn in between. The sheet of paper, which is concave at the beginning, is attached to the Transport between the belt 4 and the shaft 8 an opposite Curvature imposed, causing the initial concave curvature is eliminated. The greater the depth of penetration t1, the stronger the effect of eliminating Concavity.

An outlet contour 12 with a concave curvature is around swung out a swivel angle γ1 downwards. she forms an element for eliminating convexity. That from the element to remove concavity Sheet of paper will be opposite to one here existing convex curvature of the paper. The bigger the swivel angle γ1, the weaker the effect to remove convexity. The uncurled paper is in forwarded in the direction of R2.

Both the decurling shaft 8 and the outlet contour 12 are rigidly connected to the axis of rotation A, about which the Linkage 10 is pivotable. Swiveling the boom 10 counterclockwise increases the depth of indentation t1 and the swivel angle γ1, whereby the component for Eliminating concavity strengthened and the component to Elimination of convexity is weakened. Therefore, by Swing the boom counterclockwise an appropriate one Setting to remove incoming paper with always greater concavity can be achieved. This setting takes place via a toothed segment rigidly connected to the linkage 10 10a, which with a pinion 14a of a servomotor 14 in Intervention is.

Fig. 3 shows a sectional view of the preferred embodiment the decurling unit in a second setting. Tension the drive roller 2 and the deflection roller 6 in turn, the one or more de-arching belts 4.

The decurling wave 8 plunges here into the one or more De-warping belt 4 with an immersion depth t2 that is smaller than the immersion depth t1 of FIG. 1. One along convex upward in the direction of R1 Sheet of paper is drawn on its leading edge from the through the rubber-like de-belting 4 driven de-winding shaft 8 detected and drawn in between. The initially convex arched sheet of paper is transported between the Belt 4 and shaft 8 have only a slight convex curvature imposed, which at least caused the initial convex curvature is not reinforced. The smaller the depth of penetration t2 the weaker the convex bending effect, i.e. the effect of removing concavity.

The outlet contour 12 with its concave curvature is now over swung out a swivel angle γ2, which is smaller than the swivel angle γ1 of FIG. 1. That from the element to remove concavity Sheet of paper will be opposite to one here existing concave curvature of the paper curved. The smaller the swivel angle is γ2, the stronger the effect to remove convexity.

The pivoting of the linkage 10 clockwise causes one Decrease in the penetration depth t2 and the swivel angle γ2, thereby weakening the concavity removal component and the component to remove convexity is strengthened. Therefore, by swinging the boom here clockwise a suitable setting for removal of incoming paper with increasing convexity become. This setting is made using the Linkage 10 rigidly connected tooth segment 10a, which with the Pinion 14a of the actuator 14 is engaged.

2 and 3 each show an adjustment of the decurling unit for smoothing concave or convex Paper. Since the two settings for t and γ (t = t1, γ = γ1; t = t2, γ = γ2 with t1> t2 and γ1> γ2) through the control of the servomotor 12 continuously transferred into one another an intermediate position is also possible, in which the decurling unit behaves neutrally and none at all Performs bulge correction. This also allows transport uncurled sheets of paper through the decurling unit, without being deformed. The deburring unit can be used as a normal transport unit in this case be used. Complicated switch arrangements and case distinctions with different paper paths thereby.

Fig. 4 shows a printer with integrated decurling units E, each in the paper paths of two printing units a fuser F are connected. Here is the Compactness of the decurling units E clearly.

Fig. 5 shows a printer arrangement using roll paper R. Depending on the winding diameter, the Dewatering unit E at the printer entrance behind the cutting unit S constantly adjusted. The winding diameter of the Roll of roll paper R is made using a rotary encoder D gripped with an extension lever and serves as the basis for controlling the stepping motor of the decurling unit E.

When copying or printing, e.g. the paper quality over a constant which controls the actuating motor 14 preset, first by the operator on a control panel of the Device selected and secured by test prints. The additional adjustment of the decurling unit accordingly the print mode and the resulting runs through the printing units then takes place automatically via the Control of the servomotor 14 similar to that in FIG. 5 described control on the basis of the winding diameter.

LIST OF REFERENCE NUMBERS

2

capstan

4

decurling belt

6

idler pulley

8th

decurling shaft

10

linkage

10a

toothed segment

12

discharge contour

14

servomotor

14a

pinion

e

decurling

F

fuser

R

roll paper

S

cutting unit

D

Rotary encoder

Claims (11)

1. Decurling unit for decurling sheet substrate material, in particular paper, which has a curvature, which may be convex or concave, along a direction extending parallel to the transport direction of the substrate material, the decurling unit (2, 4, 6, 8, 10, 12) having an element (2, 4, 6, 8) for eliminating concavity in series with an element (12) for eliminating convexity, substrate material to be decurled running through both elements, characterized in that the element (2, 4, 6, 8) for eliminating the concavity is adjustable and is coupled mechanically to the likewise adjustable element (12) for eliminating the convexity in such a way that, firstly, in the event of an increase in the effect of the element (12) for eliminating convexity, a decrease occurs in the effect of the element (2, 4, 6, 8) for eliminating concavity and, secondly, if there is a decrease in the effect of the element (12) for eliminating convexity, an increase occurs in the effect of the element (2, 4, 6, 8) for eliminating concavity.
2. Decurling unit according to Claim 1, characterized in that the element for eliminating concavity is a decurling shaft (8) having an axis of rotation extending at right angles to the transport direction of the substrate material, it being possible for the decurling shaft (8) to dip into one or more extensible decurling belts (4) which are arranged parallel to one another and driven by adhesive friction and are tensioned between a drive roller (2) and a deflection roller (6) for the decurling belt or belts in the transport direction of the substrate material, the axes of rotation of the drive roller (2) and of the deflection roller (6) likewise extending at right angles to the transport direction of the substrate material, so that the decurling belt or belts (4) rests or rest in convex form on the decurling shaft (8).
3. Decurling unit according to Claim 1 or 2, characterized in that the element for eliminating convexity is an outlet contour (12) which is shaped concavely in the transport direction of the substrate material and which can be pivoted into the transport path of the substrate material.
4. Decurling unit according to Claim 1, 2 or 3, characterized in that the element for eliminating concavity and the element for eliminating convexity are rigidly connected by a linkage (10) and can be pivoted with each other about a common axis of rotation A.
5. Decurling unit according to Claim 4, characterized in that the linkage (10) is pivoted via a pinion (14a) of an actuating motor (14) by means of a toothed segment (10a) rigidly connected to the linkage.
6. Decurling unit according to one of Claims 1 to 5, characterized in that the decurling unit can be readjusted automatically, depending on the initial state of curl of the substrate material.
7. Decurling unit according to Claim 6, characterized in that the automatic readjustment is carried out on the basis of the selected printing mode.
8. Decurling unit according to Claim 6, characterized in that the automatic readjustment is carried out on the basis of the quality of the substrate material.
9. Decurling unit according to Claim 6, characterized in that the automatic readjustment is carried out on the basis of a combination of the initial state of curl of the substrate material, the selected printing mode and the quality of the substrate material.
10. Decurling unit according to one of Claims 6 to 9, characterized in that the automatic readjustment is carried out by driving the actuating motor (14) of the decurling unit.
11. Decurling unit according to Claim 10, characterized in that when wound reeled paper is used and is cut at the inlet to the printer, the diameter of the reel is registered and the actuating motor (14) of the decurling unit is driven on the basis of the registered diameter.

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