GB2269371A

GB2269371A - Sheet-feeding roller assemblies.

Info

Publication number: GB2269371A
Application number: GB9315957A
Authority: GB
Inventors: Ulrich Buschmann; Guenter Gomoll; Wolfgang Hauslaib
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1992-08-03
Filing date: 1993-08-02
Publication date: 1994-02-09
Also published as: DE4225930C2; DE4225930A1; GB9315957D0; FR2694235A1

Abstract

To feed individual sheets or sets of sheets or sheet items of varying thickness, eg open book 3, feed rollers 6 are arranged on a shaft 5, itself comprising end-to-end shaft sections 9 hingedly interconnected, eg by Cardan joints. Levers (not shown) urge at least some of the sections 9 with force F towards a counter-surface 8 or counter-rollers (not shown). <IMAGE>

Description

A 2269371 AN OFFICE MACHINE PAPER GUIDE AND TRANSPORT DEVICE This

invention relates to a paper guide and transport device for office machines, in particular computer printers.

A known transportation device for individual paper sheets and for multiple sets, i.e. for paper products of different thicknesses, comprises approximately parallel shafts carrying driven rollers, the rollers being capable of being pressed against a counter-roller which guides and transports the paper product. The shafts are bent by means of outer levers in such a way that two parallel bending lines are produced, in order to achieve a uniform pressure over the width of the paper of the rollers against the counter-roller. However, this design has the disadvantage that whilst individual sheets of papers and even multiple sets can indeed be processed or transported, printed products of considerably varying thicknesses cannot, because then the parallel bending lines are no longer practicable.

An object of the invention is to allow transport not only of individual sheets of paper and multiple sets, but also paper products which have different thicknesses transversely to the transportation direction, such as, for example, savings books.

2 An of f ice machine has in accordance with the invention a paper guide transport device comprising rollers which are rotatably driven against at least one counter-roller or counter-surf ace for guiding and transporting paper, wherein the rollers are carried on a shaft formed from a plurality of short shaft segments hingedly connected together and wherein means is provided f or individually pressing at least some of the short shaft segments against the counterroller(s) or counter-surface.

A particular advantage of this is that printed products which have considerably different thicknesses as well as single-layer and multilayer paper can be transported, without twisting of the paper as a result of unequal pressure. Thus, a uniform transportation of single-layer paper, multi-layer paper and of books can be achieved, without fear of twisting during transportation. Further advantages are that the paper guide can be mounted simply and inexpensively, because the individual short shaft segments can easily be fitted into one another and furthermore that transportation axes of different lengths can be assembled to allow construction of printers of different widths. Moreover, the result of breaking down the shaft into individual short shaft segments is smaller parts, which can be produced more inexpensively. In particular, f or production from plastics materials more economical injection-moulding tools can be selected.

Furthermore, there is a tolerance compensation in the axial 3 direction as a result of the axial displaceability of the individual joints. Axial flexures which would otherwise occur are likewise compensated for by way of the joints, so that compensation for elastic deformations is no longer necessary to such a high degree as compared with the known paper guides.

The pressing means suitably comprises a pivoted lever.

Advantageously at least some of the short shaft segments are each provided at the two ends thereof with identical joint parts. This design increases versatility, allowing assembly of the shaft with a sufficient number of rollers to obtain as many pressure points as desired on the paper surface.

In one advantageous embodiment two contiguous short shaft segments form on the outside a roller and on the inside a joint part. Such a short shaft segment can, therefore, be produced together with a roller or rollers, so that the short shaft segment having rollers f ormed at the ends is inherently stable and a flexure or some other displacement of the rollers does not occur between the rollers.

In an alternative embodiment each pivoted lever is provided with a Ushaped cutout and the rollers- are mounted f or rotation in the U-limbs by means of roller shanks. Such an alternative embodiment allows the rollers to be mounted 4 directly at the pressure point whilst still utilising the flexibility of the short shaft segments.

It is furthermore particularly advantageous that the joint parts form a Cardan joint.

A Cardan joint can now be produced from plastics parts without special expenditure and without reworking of the parts, by a first joint part formed from longitudinal grooves arranged in a cross-shaped manner with regard to the central axis of the short shaft segment on the circumference of a circular-cylindrical cavity and an associated second joint part designed in a T-shaped manner as a plug-in part and being at least once centrally longitudinally slotted. Assembly merely requires the fitting of the parts into one another without the need of further parts.

Plastics injection-moulding technology furthermore makes it possible for the joint part provided with the central longitudinal slot to be connected at the free end of the shaft to a cogwheel. A particular advantage is produced in that the cogwheel in conjunction with the longitudinal grooves on the circumference of the circular-cylindrical cavity of the first joint part makes possible the transfer of the f orce of the rotary drive over the full length of the shaft.

The invention will now be further described by way of example only with reference to the accompanying drawings, in which:

Fig. 1 is a side view of a paper guide and transport device; Fig. 2A is a partially sectional view of a shaft of the device of Fig. 1; Fig. 2B is an end view of the shaft of Fig. 2A; Fig. 3A is a similar view to Fig. 2A showing an alternative embodiment of the shaft, and Fig. 3B is an end view of the shaft of Fig. 3A.

An of f ice machine in the form of a computer printer 1 is shown. A paper guide 2 is provided for a paper product 3 which consists of individual sheets, multiple sets or books, such as e.g. savings books. While individual sheets represent a printed product of different thickness, the differences in thickness increase in the case of multiple sets and naturally rise sharply in the case of books. The particular problem comes about as a result of the differences in thickness of the product transversely to its transportation direction 4.

6 The paper guide 2 is f ormed from a shaft 5 which carries several rollers 6 arranged at intervals and either counterrollers 7 arranged on a second parallel shaft 5 (see Fig. 2B) or a counter surface 8.

Each separate individual shaft 5 with the rollers 6 (or 7) consists of individual short shaft segments 9 which are connected together in a hinged manner. At least individual ones of the short shaft segments 9 are in each case supported or mounted by means of a pivoted lever 10 and can be pressed against the counter-surface 8. For this purpose the pivoted lever 10 is held or rotatably drivable by means of a pivoted shaft 10a on one end. The pivoted lever 10 has at the other end a bearing bush 10b, in which the shaft 5 as a whole can rotate or in which in each case a short shaft segment 9 can rotate. The pivoted lever 10 can thus exert a force F on the rollers-6.

Each short shaft segment 9 can be provided at its ends 9a and 9b with identical joint parts lia or lib. In the arrangement of Fig. 2A alternate first short shaft segments 9 have, symmetrically to the central axis 9c, an inner joint part at both ends 9a and 9b and the other short shaft segments 9 have in each case outer joint parts. Thus, in the case of two contiguous short shaft segments 9, the result is, on the outside, a roller 6 and an inner joint.

In an alternative embodiment shown in Figs. 3A and 3B the 7 pivoted levers 10 are each provided with a cutout 12 having U-limbs 12a and 12b. In each case a roller 6 is rotatably mounted on its roller shanks 6a in the U-limbs 12a, 12b.

Accordingly, here the joint parts on both sides are accommodated inside a cavity 14, which saves space.

The respective joint parts 11a and 11b form a Cardan joint 11c. The Cardan joint lic is, in the case of production of the shaft 5 consisting of the short shaft portions 9 by injection-moulding from plastics material. formed by means of longitudinal grooves 13 on the circumference of the cavity 14, which extend in an axially parallel manner with regard to the central axis 9c. Each rod-form short shaft segment 9 is designed as a plug-in part 15. As a result of a longitudinal slot 16 in the end of the rod-shaped short shaft segment 9, this can either be superimposed onto a core f lat journal 6b as shown or, as a result of the longitudinal slots 16 which allow a resilient spreading, can be inserted into the cavity 14.

Upon rotary movement of the shaft 5, the individual short shaft segments 9 are displaced at an angle a depending on the dif f erent thickness of the paper product 3 at 3a and 3b, see Fig. 1.

The rotary drive consists of a cogwheel 18 which is fastened to the shank end 17 of a f inal rod-shaped short shaf t segment 9 and which is driven by the pinion of the 8 driving motor 18a. Differences in height 19 occurring by reason of the angle a are accommodated.

9

Claims

CLAIMS-:

1. An office machine having a paper guide and transport device comprising rollers which are rotatably driven against at least one counter-roller or counter-surface for guiding and transporting paper, wherein the rollers are carried on a shaft formed from a plurality of short shaft segments hingedly connected together and wherein means is provided for individually pressing at least some of the short shaft segments against the counter-roller(s) or counter-surface.

2. An office machine as claimed in Claim 1, wherein the pressing means comprises a pivoted lever.

3. An office machine as claimed in Claim 2, wherein each pivoted lever has a U-shaped cutout and wherein a roller is rotatably mounted by roller shanks in the U-limbs.

4. An office machine as claimed in claim 2, wherein contiguous short shaft segments form, on the outside, a roller and, on the inside, a joint.

5. An office machine as claimed in any preceding claim, wherein each short shaft segment is provided at its ends with identical joint parts for forming the hinge connections.

6. An office machine as claimed in any preceding claim, wherein the hinge connections are produced by joint parts which form a Cardan joint.

7. An office machine as claimed in any preceding Claim, wherein the hinge connections are produced by joint parts including a first joint part compr:sing longitudinal grooves arranged generally in a cross-shaped manner with respect to the central axis of the short shaft segments on the circumference of a circular-cylindrical cavity and a second joint part comprising a plug-in part with at least one central longitudinal slot.

8. An office machine as claimed in any preceding claim, wherein rotary drive means for the rollers is provided, comprising a cogwheel connected at a free end of the shaft which is driven by a driving motor.

9. An office machine as claimed in Claim 8 when dependent on Claim 7, wherein the free end of the shaft has a second joint part and is connected to the cogwheel via the central longitudinal slot of the second joint part.

10. An office machine substantially as hereinbefore described and illustrated in the accompanying drawings.