JPH04244873A - Sheet aligning device for printer - Google Patents

Abstract

PURPOSE: To rapidly and uniformly align sheets to a guide rail with a simple structure. CONSTITUTION: The apparatus for aligning sheets in a printer comprises a drawing means 13 having a drive roller 31 and an oscillating roller 27 parallel to a driving means 11 of the sheet by a drive roller 20 and a pinch roller 21. A rubber coating supported at one end of a shat 29 of the roller 27 to a long hole to oscillate in a sheet conveying direction to cover the roller 31 has higher flexibility than that of the coating of the roller 27 and a followability. When the roller 21 is opened and the sheet is driven at the means 13 side, the roller 27 is oscillated to urge a lateral edge of the sheet gradually to a guide surface, thereby aligning the sheets.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD This invention relates generally to systems for aligning sheets in printing presses, and more particularly to systems for aligning sheets in inkjet printers and similar devices for use with microprocessor-based computers. It's about a system for

0002

BACKGROUND OF THE INVENTION In printers such as inkjet printers and similar devices used with microprocessor-based computers, one edge of a sheet of paper is aligned with a linear guide surface. Paper must be processed quickly and uniformly. Such alignment is important, for example, in providing consistent print margins from sheet to sheet. Alignment is also important to reduce paper jams during printing.

US Pat. No. 4,384,298 discloses an X-Y plotter for plotting on a paper web without locating holes or similar means for maintaining web alignment. In particular, FIGS. 3a and 3 of the patent
In b, an idler roller is shown for feeding the web against the stop member as the paper traverses the paper holding/drive assembly of the plotter. According to the patent,
By allowing free movement at the forward end of the idler roller shaft and not allowing free movement at the retraction end of the shaft, the edge of the paper can be can be continuously pressed against the stop member.

0004

SUMMARY OF THE INVENTION In general, the present invention provides for moving individual sheets of paper parallel to and in contact with a linear guide as the sheets move on a generally flat surface toward a printing station. Bringing in a system for aligning relationships. In a preferred embodiment, the alignment system includes a drive roller for driving each paper back and forth in a plane, and a drive roller mounted opposite the drive roller to draw the lateral edges of the paper parallel to and in contact with the guide rails. and a swinging roller that changes direction in the direction of paper movement. Both the drive roller and the oscillating roller are rubber coated, and the rubber coating on the drive roller has a compliance rate (a dgree of
The durometer value is smaller than that of the rubber coating of the rocking roller in order to provide better compliance. actual,
The durometer value of the rubber coating on the swing roller is about 70 or less, but the durometer value of the rubber coating on the drive roller is about 5.
5 or less.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows one embodiment of an alignment system for handling sheets of paper as it moves along plane 5 toward a printing station (not shown). For simplicity and clarity, only a portion of the paper is shown in the figure. Generally, the paper is paper, but other printable materials can be used.

Generally speaking, the alignment system of FIG. 1 includes a rail-like linear guide member 9 and towin means, indicated by the numeral 13, for aligning the sheets with respect to the linear guide member. include. In the illustrated embodiment, the linear guide member 9 is shown as a rail extending in the direction of intended movement of the sheet and oriented to provide a guide surface 10 perpendicular to the plane 5. The retracting means 13 is placed close to the linear guide member 9 for aligning the printing paper so that the right lateral edge of the paper is aligned parallel to and in contact with the guide surface 10.

The system of FIG. 1 further includes drive means, generally designated 11, for driving the printing paper in a direction parallel to the linear guide member 9. The system of FIG. In the illustrated embodiment, the drive means 11 includes a first drive roller 20 and a pinch roller 21 mounted opposite the drive roller. Note that the first drive roller 20 extends upwardly through an opening in plane 5 to engage the underside of each sheet as it moves along plane 5. However, in the illustrated embodiment, an opening for the drive roller 20 is not specifically shown.

In fact, the surface of the first drive roller 20 is coated with a material to enhance the engagement between the drive roller and the driven paper.
It is covered with a rough material. pinch roller 2
The surface of 1 is preferably formed from a relatively hard (ie, high durometer) material such as silicone rubber. In contrast, the surface of the first drive roller 20 is formed from a material that has a high coefficient of friction, such as rubber, and is relatively soft (ie, has a low durometer) relative to the pinch roller 21. Therefore, the first drive roller 20
and associated pinch rollers 21 have only limited compliance with the driven paper.

Furthermore, in the embodiment shown in FIG. 1, the retraction means 13 includes an oscillating roller 27 placed in a position to engage the upper surface of the sheet moving on the plane 5. In fact, the swinging roller 27 is rotatable on the shaft 29. As will be explained further below, on the shaft 29 the swinging roller 27 can be pivoted (ie rocked) back and forth in a horizontal plane.

Furthermore, the retraction means 13 of FIG. 1 includes another drive roller 31 mounted to rotate opposite the swinging roller 27. First drive roller 2
0, a second drive roller 31 is mounted below the planar member 5 and extends upwardly through an opening in the planar member to engage the underside of a sheet of paper traveling on the planar member 5. Also in this case, the opening of the second drive roller 31 is not particularly shown. The first and second drive rollers 20, 31 are
It is attached to a common drive shaft 32 driven by a drive motor 34.

In fact, the swinging roller 27 and the second drive roller 31 are coated with a thin rubber coating as shown. The rubber coating is actually about 1/16 inch thick. It is desirable that the rubber coating of the swing roller 27 is harder than the rubber coating of the second drive roller 31. For example, the rubber coating on the rocker roller 27 can have a durometer value of about 70, and the rubber coating on the second drive roller 31 can have a durometer value of about 55 or less. It must be noted that in the durometer, the rubber coating of the second drive roller 31 is to some extent compliant. This can be achieved, for example, by making the second drive roller 31 thicker.

FIG. 2 shows one embodiment of a structure for mounting an oscillating roller 27 on a shaft 29. FIG. In the illustrated embodiment, shaft 29 passes between legs 41 and 43 of bifurcated member 45 . It must be noted that the leg 43 is closest to the linear guide member 9 and the leg 41 is placed further away from the linear guide member 9. A generally circular hole 47 is formed in leg 43 for receiving one end of shaft 29. In fact, the inner diameter of the circular hole 47 is sufficiently larger than the outer diameter of the shaft 29, so that the shaft can freely rotate with limited pivoting.

In FIG. 2, the elongated hole 49 is further inserted into the bifurcated member 4.
It must be noted that it is formed on leg 41 of 5. Elongated hole 49 receives the end of shaft 29, allowing the shaft to pivot horizontally through a limited arc. In fact, the slot 49 is dimensioned such that the pivoting movement of the shaft 29 is limited to only a few degrees.

Referring again to FIG. 1, the sheet alignment system includes biasing systems 61 and 63 (eg, springs and solenoids), respectively, for selectively engaging rocker roller 27 and pinch roller 21. include. In fact, biasing systems 61 and 63
It is operated according to a selective sequence of operations in which the pinch roller 21 engages the paper, disengages the rocker roller 27, and vice versa. However, in any case, the first and second drive rollers 20 and 3
1 remains in contact with the underside of the paper supported on plane 5. However, the first drive roller 20 cannot effectively drive the paper until the pinch roller 21 is biased downwardly with respect to the paper, and similarly, the first drive roller 20 cannot effectively drive the paper until the rocker roller 27 is biased downwardly. Second drive roller 31
It is understood that the printer cannot drive the paper.

The operation of the system of FIG. 1 will now be described. The paper to be printed moves 1 time on the plane 5 in the direction of the arrow.
The first thing you need to understand is that it is fed one by one. As each sheet moves over the plane 5 for printing, the leading lateral edge of the sheet moves into the roll gap between the rocker roller 27 and the second drive roller 31 or similarly between the first drive roller 20 and the pinch roller. It enters the roll gap between 21 and 21. Thereafter, the paper can be driven only by the first or second drive roller.

When it is desired to align the sheets, the pinch rollers 21 are disengaged and the swinging rollers 27 are moved to engage the sheets. Next, when the paper is driven forward by the second drive roller 31, the shaft 29 begins to rotate in the forward direction. As the pivoting action continues, the rocking roller 27 applies force through frictional engagement with the paper. One component of the force is parallel to the guide surface 10 in the direction of paper travel and therefore serves to drive the paper forward. The other component is a retraction force that serves to pull the paper generally towards the guide rail member 9. It is important to note that the effectiveness of the retraction force that forces the paper toward the guide rail depends on the compliance of the rubber coatings of the rocker roller 27 and the second drive roller 31.

After the swing roller 27 has rotated the shaft 29 within the elongated hole 49 to the maximum extent in the forward direction, the rotation direction of the second drive roller 31 is reversed and the paper is moved in the backward direction. to drive. In such a case, the shaft 29 pivots towards the rear end of the elongated hole 49 and the swinging roller 27
A retraction force is again applied which serves to pull the paper generally towards the guide rail 9. In fact, the lateral edges of the paper can be made parallel to and in contact with the linear guide member 9 by driving the rocking roller 27 back and forth a few times. The operation typically takes about 1/4 second.

In fact, for a given movement of the sheet forwards or backwards on the plane 5, the sheet generally moves towards the guide surface 10 by a fixed distance. For example, the alignment system of FIG. 1 may be constructed such that the lateral edge of the paper moves approximately 1/80 of an inch toward the guide member when the paper moves forward or backward one inch.

[0019]

As described above, according to the present invention, sheets can be quickly and uniformly aligned with respect to guide rails with a simple structure, uniform printing on sheets can be achieved, and paper jams can be prevented. be able to.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention.

FIG. 2 is a sectional view taken along line 2-2 in FIG. 1;

[Explanation of symbols]

5: Plane 9: Linear guide member 10: Guide surface 11: Drive means 13: Retraction means 20: Drive roller 21: Pinch roller 27: Swinging roller 29: Axis 31: Drive roller 34: Drive motor 61, 63: Biasing system

Claims (2)

[Claims] Claim 1: While conveying the sheet toward the printing section,
In a sheet alignment device that aligns individual sheets in a positional relationship parallel to and in contact with a guide rail, a guide rail having a straight edge that guides the sheets along the conveying direction of the sheet on a flat plate surface, and a guide rail on the flat plate surface a drive roller that drives each sheet, and a drive roller that is provided almost opposite the drive roller to pull the sheet so that the lateral edge of the sheet is parallel to and in contact with the guide rail. It consists of an oscillating roller provided to oscillate in the transport direction, and a rubber coating that covers the drive roller and the oscillating roller, and the rubber coating of the drive roller is the rubber coating of the oscillating roller. 1. A sheet aligning device for a printer, characterized in that the sheet aligning device is formed to be substantially more flexible than the conventional sheet aligning device. 2. A flat plate surface for supporting the sheet during conveyance of the sheet to a printing section; a linear guide rail extending along the flat plate surface for guiding the lateral edges of each sheet; a drive roller that drives the sheet along;
A rocker is provided substantially opposite the drive roller and pulls the sheet so that the lateral edge of the sheet is parallel to and in contact with the guide rail while the sheet is being driven along the flat plate surface. The roller includes a moving roller, and a rubber coating that covers the drive roller and the swinging roller, and the rubber coating of the drive roller is formed to be substantially more flexible than the rubber coating of the swinging roller to improve followability. A sheet aligning device in a printer characterized by having the following features.