JPS60128428A - Device for correcting displacement of original - Google Patents

Abstract

PURPOSE:To correct the displacement of an original easily during the feeding of the original by arranging pairs of photodetecting elements on plural lines rectangular to the original feeding direction and detecting the inclination of the original from the time difference of outputs of respective pairs of photodetecting elements. CONSTITUTION:The original P is fed in the arrow direction and the pairs of photodetecting elements (1, 2), (11, 12), (21, 22) are arranged on straight lines y1-y3 rectangular to the feeding direction. When the original P is inclined at the back end as shown in the drawing, and delayed at the photodetecting element 2 by DELTAx1 from the photodetecting element 1, the quantity of displacement becomes DELTAx1=DELTAtheta.DELTAY=S.DELTAt and the angle of displacement becomes DELTAtheta=DELTAt.S/ DELTAY (wherein, DELTAt is delay time and S is speed). The quantity of displacement DELTAx and the width DELTAY are inputted to a data selecting machine DS, compared with previously inputted reference values by a comparator COM and the deviations with the reference values are found out by a measuring device COU and inputted to a driving device DR through a comparator COM to attain numerical control NC.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a document position correction device in a copying machine, etc. More specifically, the present invention relates to an automatic document position correction device for biographical processing, etc. in a copying machine, etc. This invention relates to a correction device.

Prior Art In conventional automatic document feeders, the misalignment of the document during document transport is unknown until the document comes into contact with the registration gate.
The amount of deviation on the front side or the rear side with respect to the traveling direction of the original can be known only after the original comes into contact with the registration gate.

Furthermore, it is not possible to know from what location the document shift occurs while the document is being conveyed. Therefore, it is inevitable that the timing of correcting the misalignment of the original is delayed or that the misalignment of the original cannot be reliably grasped, resulting in defective copies.

OBJECTS OF THE INVENTION The object of the present invention is to provide a document displacement correction device that quickly detects document displacement during document transport in a conventional copying machine as described above, corrects the document position, and always obtains good copies. It is to provide.

Structure of the Invention An object of the present invention is to arrange a pair of light receiving elements on a plurality of lines perpendicular to the document feeding direction of a document transport path in a copying machine, etc. Detects the difference in displacement between the front edge (front edge) and the rear edge (back edge) of
This is achieved by controlling the operation of the document conveying device based on the displacement difference between each pair of light receiving elements.

The present invention will be explained in more detail with reference to the drawings in FIG. 1. In FIG.
2) is a straight line y1. which is perpendicular to the document feeding direction on the document transport path. y2 and y indicate a pair of light receiving elements arranged above, p', p'' and p /// are the rear edge of the document being conveyed in the direction of the arrow ← the rear edge of the document in the document conveyance direction) The figure shows a state in which the original P' begins to pass through each light-receiving element pair.Now, when the original P' is being conveyed at a speed of 511 LV/sec, the original shifts within a time Δ. When a displacement angle of Δθ□ is formed with the straight line y8, and even if the trailing edge of the original passes through the light-receiving element (1), a distance S of Δx1 (this is called the displacement amount) remains on the light-receiving element (2). The following relationship is obtained; displacement Δx□=Δ01·ΔY=8−Δt (I) Here, ΔY is the distance between the light receiving elements (1) and (2).

From these equations, the displacement or displacement angle in the direction of the straight line x2 passing through the light receiving element (2) and perpendicular to limy□ is expressed as Δt,
It can be detected from ΔY and S. fruit. A method for detecting these displacements will be explained with reference to FIG.

While the document passes over the light receiving element (1), the light from the light source is blocked, so the output of the light receiving element (1) is zero (point A in Figure 2 (1)). , when the trailing edge of the document passes the light receiving element (1), the output of the light receiving element becomes the second (1)
The output gradually increases from point B in the figure until it reaches the 0 point, and the output remains constant between O and D when light is received without an original. Then, the front edge of the next document reaches the light receiving element (1), and gradually the front edge of the next document reaches the light receiving element (1).
) is shielded from the light source, the output of the light receiving element (1) becomes the second
From point D in Figure (1), it gradually decreases to zero (point E),
The state of zero continues until this original passes through the light receiving element ((
F, -F).

When the conveyed document is conveyed to the final registration line without any deviation, the outputs of the light receiving elements (1) and (2) both become as shown in FIG. 2 (1).

Now, if the original is displaced by the amount and angle of displacement shown in Figure 1, the change in the output of the light-receiving element (1) when the trailing edge of the original passes through the light-receiving element (1) is Figure 2 (1
), but the change in the output of the light receiving element (2) when the rear edge passes through the light receiving element (2) is shown in G-H-I-J- in Figure 2 (2). It will be done. By the way, the light receiving element (1
) and (2), the output value gradually changes during the sections where the output increases (between B-0 or H-I) or decreases (between D-1 or J-), so the light receiving element (1) and Figure 2 (1) Binarizes each output change of the light receiving element (2)
is converted as shown in FIG. 2(3), and FIG. 2(2) is converted as shown in FIG. 2(4). By A/D converting the thus obtained Fig. 2 (3) and (4), it is possible to find the difference Δt between the output start time T0 of the light receiving element (1) and the output start time T2 of the light receiving element (2). Therefore, from formulas (I) and (1), Δθ
1 and Δx1 can be known. Hereinafter, similarly for the light receiving element pairs (11, 12), (21, 22)... ΔX ΔX ...°Δ0 Δθ .
... is obtained, 2, 3 #2. 3. The above explained displacement in the document transport direction (X-axis direction), but in the direction perpendicular to the document transport direction (y-axis direction).
The same can be said about the displacement amount (Δy) and the displacement angle (Δθ).

The displacement amounts (ΔX, Δy) thus obtained are input to the control circuit of the document conveying device shown in FIG. That is, the third
In the figure, reference data for document transport is input in advance to the data sorter DS, and the displacement amounts ΔX and Δy obtained from each light receiving element pair are input to the DS K, and then this information is input to the comparator COM. , here, the reference value A and the measured value B are compared, and if A>B, the measured value B is determined by the measuring instrument O0U.
, add the value of IA-J to A (in the case of B, subtract 1 person - Bl from the measured value B, feed this back to the comparator, input this value to the drive device DB, and then Numerical control is performed by the numerical control circuit NO of the feeding device, and by correcting the deviation of the original until the original finally reaches the registration line, good copies are always produced.

Effects of the Invention According to the document displacement correcting device of the present invention, when operating a self-document feeder for historical processing in a copying machine, etc., the document displacement correction device prevents the document from reaching the registration line before the document finally reaches the registration line. It is possible to quickly detect misalignment of the original, uneven feeding of the original, etc. and automatically correct the displacement of the original when the original is in the original position, so that good copies can always be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the principle of the device of the present invention, FIG. The figure is a block diagram for explaining the operation of the document displacement correction device according to the present invention. Symbols in the figure: 1, 2, 11.12.21.22... Light receiving element, p', p", P"... Original document. (3 others) Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A pair of light-receiving elements is arranged on a plurality of lines perpendicular to the document feeding direction of the document transport path in a copying machine, etc., and the displacement between the front and trailing edges of the document when the document passes through each pair of light-receiving elements is measured. A document displacement correction device for a copying machine or the like, which detects a difference in displacement and controls the operation of a document conveying device based on the difference in displacement between each pair of light receiving elements.