GB1582825A

GB1582825A - Sheet offsetting apparatus and method

Info

Publication number: GB1582825A
Application number: GB1883678A
Authority: GB
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1977-08-22
Filing date: 1978-05-10
Publication date: 1981-01-14
Also published as: FR2401086B2; DE2830404A1; FR2401086A2; BR7805404A; JPS5435964A; JPS5522385B2; DE2830404C2

Description

(54) SHEET OFFSETTING APPARATUS AND METHOD (71) We, INTERNATIONAL BUSINESS COR PORATION, a Corporation organized and existing under the laws of the State of New York in the United States of America, of Armonk, New York 10504, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to sheet lateral offsetting apparatus and method for offsetting sheets laterally, and is an improvement in or modification of that disclosed and claimed in the complete specification of our Co- pending application for Letters Patent No.

37507/77 (Serial No. 1,572,143).

In that application is claimed, inter alia, a method of offsetting sheets laterally with respect to other sheets, comprising the steps of feeding sheets in a predetermined direction along an initial path of travel, directing selected sheets along a second downstream path at least partly curved about an axis or axes skewed relative to an axis perpendicular to the predetermined direction to a third downstream path, and directing other sheets from the initial path to the third path without following the second path, thereby to offset them laterally from the selected sheets.

In addition, there is claimed sheet lateral offsetting apparatus for offsetting selected sheets laterally with respect to other sheets, comprising feeding means for feeding sheets in a predetermined direction along an initial path of travel and sheet directing means for diverting selected sheets along a second downstram path at least partly curved about an axis or axes skewed relative to an axis perpendicular to the predetermined direction to a third downstream path, and for directing other sheets from the initial path to the third path without following the second path, thereby to offset them laterally from the selected sheets.

According to the present invention, a method of offsetting a sheet laterally with respect to its path of travel, comprises the steps of feeding a sheet along a feedpath in a feed direction, directing the sheet through a loop-shaped path formed about an axis skewed relative to an axis perpendicular to the feed direction, and selectively directing the sheet out of the loop-shaped path after a number of loops therethrough, along an exit path in a predetermined direction.

the sheet thereby being offset laterally with respect to the predetermined direction by an amount which is a function of the number of loops performed.

According to another aspect of the invention, sheet lateral offsetting apparatus for offsetting sheets laterally with respect to a path of travel, comprises feeding means for feeding sheets along a feed path in a feed direction, a loop-shaped path leading from the feed path and disposed about an axis skewed relative to an axis perpendicular to the feed direction, and means for selectively diverting sheets from the loop-shaped path to an exit path in a predetermined direction so as to offset a sheet laterally with respect to the predetermined direction by an amount which is a function of the number of loops performed.

The scope of the invention is defined by the appended claims; and how it can be carried into effect is hereinafter particularly described with reference to the accompanying drawings, in which: Figure 1 is a schematic view of a copier/ duplicator/printer system incorporating offsetting apparatus according to the present invention; Figure 2 is a schematic side view of a loopshaped guide structure for effecting lateral offsetting of the sheets; Figure 3 is a schematic plan view of the structure of Figure 2; and Figure 4 is a schematic view of a path of seven and one-half loops in the loop-shaped guide structure of Figure 2.

Sheet offsetting apparatus 4 (Figure 1) according to the present invention may be used to offset sheets from a copier/duplicator/printer system. Sheets are fed by a feeding mechanism 1 for feeding sheets from a copying or printing station 2 to a bin type collection station 3 along a guide path including offsetting apparatus 4 at the entrance to the collection station 3. A control panel 5-contains switches to control operation of the system, for example, to set it in a duplicating mode or printing mode, to select numbers of copies and for setting other operating functions. A counter 14 is included to operate a solenoid 15 to control the offsetting apparatus as described below.

The feeding mechanism includes pairs of rollers along the sheet guide path. One of each pair of rollers, the drive roller, is positively driven against a sheet between the drive roller and the other roller which is an idler roller. The sheet offsetting apparatus (Fig. 2 and 3) provides a sheet support surface and entry guide 7 for sheets entering in a direction of travel 9. A pair of rollers 17, one of which is driven, are located along the guide path. The axes of the rollers 17 are normal to the direction 9. The guide structure includes a curved portion 8 set at a skew angle, other than a right angle to the original direction 9 of travel of the sheets in the guide 7. The curved portion 8 extends through 1800, so that sheets are diverted from their direction of travel 9 and emerge from the curved portion 8 in a plane parallel to the plane of guide 7 and in a direction of travel 10 at an angle to the direction 9 due to skew of the curved portion 8. A pair of rollers 18, one of which is driven, are located at the end of the curved portion 8 and their axes are normal to the direction 10.

The guide structure includes a curved portion 11 set at the same skew angle to the original direction 9 as the portion 8. The curved portion 11 extends through 1800 and leads into the guide 7 in the vicinity of the rollers 17. Leading from the guide structure in the vicinity of the rollers 18 is a sheet support surface and exit guide 12 parallel to the guide 7 and set to provide a path for sheets in the direction 10. A deflector 100 is selectively movable to guide sheets from the rollers 18 either into the curved portion 11 or into the exit guide 12.

The curved portions 8 and 11 rejoined by straight sections in which the rollers 17 and 18 are positioned. The structure forms a loop disposed between the entry and exit guides and having an axis at a skew angle to the directions of travel of the sheet on the guides it can readily be seen that this is normal to an axis bisecting the angle between the directions.

As a sheet passes around the curved portion 8 for the first time, the path 20 of one edge (Fig. 3), which is initially parallel to the direction 9, is deflected to a path 21 parallel to the direction 10. If the deflector 100 is then set to guide the sheet to the exit guide 12, the sheet enters the guide in a non-offset position. If the deflector 100 is set to guide the sheet around the loop, the path of the one edge is substantially helical and upon leaving the curved portion 8 for the second time, occupies a path 22 parallel to the direction 10. If the deflector 100 is set to guide the sheet to the exit guide 12, the sheet enters the guide in a single offset position, the offset being that due to the skewed loop. If the deflector 100 is set to guide the sheet around the loop again, the path of the one edge continues to be substantially helical and upon leaving the curved portion 8 for the third time, occupies a path 23 parallel to the direction 10. This gives a double offset to the sheet.

It will be appreciated that by operating the deflector after an appropriate number of sheet traverses of the loop, a sheet can be offset by a selected offset. The amount of offset is N times the offset due to one traverse, where N is the number of traverses. The number of possible offsets is limited by the width of the exit guide 12 which leads to the collection station 3.

The rollers 17 and 18 are arranged so that they have no influence on the direction of movement of a sheet but merely drive it onwards in the direction in which it arrives at the rollers. Their axes are thus normal to the feed direction. It is convenient to have several pairs of rollers staggered across the width of the flat sections, so as to keep the length of the latter in the sheet path as short as possible.

In order to maintain feeding of a sheet throughout its path of travel, the distance between rollers 17 and 18 is less than the minimum length of sheet to be handled. The distance around the loop from rollers 17 to rollers 18 must be greater than the maximum length of sheet to be handled.

The disposition of the guides 7 and 12 causes the angular difference between sheets entering and exiting. It will be appreciated that the exit guide 12 may be disposed anywhere around the circumference of the loop structure, from which it is possible to extract sheets. Thus the guides 7 and 12 might be aligned. In such a case a sheet will leave in a direction parallel to that in which it entered, rather than at an angle. Additional sets of rollers may be needed if the space between them becomes too great.

The offset per loop traversed is related to the skew angle and the length of the loop in the direction of sheet travel, and is in general 1/sin o, where 1 is the length of the loop in the direction of sheet travel and o is the skew angle, that is the angle between the axis of the curved portions and the normal to the direction of initial sheet advance. The length of the 'loop may be affected by the number and size of straight sections.

The guide structure comprises a pair of wall members which closely overlie each other to contain the paper as it is fed through the trough. Although a continuous double wall construction is shown, other means may be used for guiding the sheets through their curved path. For example, the inner wall may be replaced by strategically placed guide surfaces at the proper orientation with respect to the curved portions of ,the loop to hold the sheets' against the surface of the outer wall.

The diverter 100 is actuated by the solenoid 15 operated by a switch under the control of the counter 14 in the control panel. By counting the number of loop traverses by a sheet, the counter gives an indication of offset, which may be compared with that selected or computed by a control circuit in the panel..

Figure 4 depicts a helical path 101 followed by a point on a sheet as it loops repeatedly through a circular cylinder trough such as shown in Figure 2. For simplicity the trough is assumed to be circular in cross section, that is, the flat sections have been disregarded.

As used herein, the term helical path is intended to mean the path of a point in the plane of a sheet, as the sheet moves around the axis of the skewed trough, whether or not it includes flat sections. The sheet approaches the trough with its leading edge disposed as shown by broken line 102. The point being considered is travelling along straight line 120. As the sheet enters the trough, this point describes the helical path 101, makes approximately seven and one-half loops, and exits along straight line 121. The leading edge of the sheet is now disposed as at 103.

The skewed axis of the trough is represented by broken line 104 which lies at an angle to both lines 102 and 103. Around the path 101, drive rollers, for example, 107 and 108, are supported on the axes 105 and 106 normal to path 101 to impart drive force to the sheet as it traverses the path. The axes are also tangent to the cylinder, but only at a point so that the drive rollers should be infinitely thin in order to drive the paper perfectly. Very narrow drive and idler rollers may be used, or the rollers may be positioned on flat sections.

In Figure 3, only one of each pair of rollers is shown, whereas in practice, spaced rollers would extend across the whole width of the paper path.

It will be appreclated that offset is achieved by taking the sheet out of the path after different numbers of loops. The entire sheet is bent to conform to the loop guide structure during multiple looping. The length of the loop defined by the guide is such that the leading and trailing sheet portions do not overlap, that is, a gap exists between the two ends of the sheet as it multi-loops through the guide.

WHAT WE CLAIM IS: 1. A method of offsetting a sheet laterally with respect to its path of travel, comprising the steps of feeding a sheet along a feed path in a feed direction, directing the sheet through a loop-shaped path formed about an axis skewed relative to an axis perpen dicular to the feed direction, and selectively directing the sheet out of the loop-shaped path after a number of loops therethrough, along an exit path in a predetermined direction, the sheet thereby being offset laterally with respect to the predetermined direction by an amount which is a function of the number of loops performed.

2. A method according to claim 1, in which the predetermined direction and feed direction lie at an angle to one another and to the skewed axis.

3. A method according to claim 2, in which the exit path is in a different plane to the feed path.

4. A method according to claim 3, in which the exit and feed paths are in parallel planes.

5. A method according to any preceding claim, in which the loop-shaped path is substantially helical.

6. A method of offsetting a sheet, substantially as hereinbefore particularly described with reference to the accompanying drawings.

7. Sheet lateral offsetting apparatus for offsetting sheets laterally with respect to a path of travel, comprising feeding means for feeding sheets along a feed path in a feed direction, a loop-shaped path leading from the feed path and disposed about an axis skewed relative to an axis perpendicular to the feed direction, and means for selectively diverting sheets from the loop-shaped path to an exit path in a predetermined direction so as to offset a sheet laterally with respect to the predetermined direction by an amount which is a function of the number of loops perforr ed.

8. Apparatus according to claim 7, in which the feed direction and predetermined direction lie at an angle to one another and to the skewed axis.

9. Apparatus according to claim 8, in which- the exit path is in a different plane to the feed path.

10. Apparatus according to claim 9, in which the exit and feed paths are in parallel planes.

11. Apparatus according to claims 7, 8, 9 or 10, in which the loop-shaped path is substantially helical.

12. Apparatus according to any of claims 7 to 11 including two sheet feeding means spaced along the loop-shaped path.

13. Apparatus according to claim 12, in which the distance between the sheet

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. other to contain the paper as it is fed through the trough. Although a continuous double wall construction is shown, other means may be used for guiding the sheets through their curved path. For example, the inner wall may be replaced by strategically placed guide surfaces at the proper orientation with respect to the curved portions of ,the loop to hold the sheets' against the surface of the outer wall. The diverter 100 is actuated by the solenoid 15 operated by a switch under the control of the counter 14 in the control panel. By counting the number of loop traverses by a sheet, the counter gives an indication of offset, which may be compared with that selected or computed by a control circuit in the panel.. Figure 4 depicts a helical path 101 followed by a point on a sheet as it loops repeatedly through a circular cylinder trough such as shown in Figure 2. For simplicity the trough is assumed to be circular in cross section, that is, the flat sections have been disregarded. As used herein, the term helical path is intended to mean the path of a point in the plane of a sheet, as the sheet moves around the axis of the skewed trough, whether or not it includes flat sections. The sheet approaches the trough with its leading edge disposed as shown by broken line 102. The point being considered is travelling along straight line 120. As the sheet enters the trough, this point describes the helical path 101, makes approximately seven and one-half loops, and exits along straight line 121. The leading edge of the sheet is now disposed as at 103. The skewed axis of the trough is represented by broken line 104 which lies at an angle to both lines 102 and 103. Around the path 101, drive rollers, for example, 107 and 108, are supported on the axes 105 and 106 normal to path 101 to impart drive force to the sheet as it traverses the path. The axes are also tangent to the cylinder, but only at a point so that the drive rollers should be infinitely thin in order to drive the paper perfectly. Very narrow drive and idler rollers may be used, or the rollers may be positioned on flat sections. In Figure 3, only one of each pair of rollers is shown, whereas in practice, spaced rollers would extend across the whole width of the paper path. It will be appreclated that offset is achieved by taking the sheet out of the path after different numbers of loops. The entire sheet is bent to conform to the loop guide structure during multiple looping. The length of the loop defined by the guide is such that the leading and trailing sheet portions do not overlap, that is, a gap exists between the two ends of the sheet as it multi-loops through the guide. WHAT WE CLAIM IS:

1. A method of offsetting a sheet laterally with respect to its path of travel, comprising the steps of feeding a sheet along a feed path in a feed direction, directing the sheet through a loop-shaped path formed about an axis skewed relative to an axis perpen dicular to the feed direction, and selectively directing the sheet out of the loop-shaped path after a number of loops therethrough, along an exit path in a predetermined direction, the sheet thereby being offset laterally with respect to the predetermined direction by an amount which is a function of the number of loops performed.

13. Apparatus according to claim 12, in which the distance between the sheet

feeding means is less than the minimum length of sheet to be handled.

14. Apparatus according to claim 12 or 13 in which the length of the loop-shaped path is greater than the maximum length of sheet to be handled.

15. Sheet offsetting apparatus, substantially as hereinbefore particularly described with reference to the accompanying drawings.