JPH01138548A - Original size detector - Google Patents

Abstract

PURPOSE:To prevent an original size from being detected mistakenly by arraying light emitting elements and photodetectors so that optical axes from the light emitting elements to the photodetectors can tilt with respect to an original placed on a table glass. CONSTITUTION:The light emitting elements 9a and 9b and the photodetectors 10a and 10b are arrayed so that the optical axis l1 and l2 from the elements 9 and 9b to the photodetectors 10a and 10b tilt in the direction in which the original 6 is placed. Therefore, even if part of the original 6 floats from the table glass 5, the optical axes l1 and l2 are blocked by the original 6 as long as the original is on the optical axes l1 and l2 because they pass not only by the floating part of the original 6 but also a part in contact with the table glass 5. Thus the original size can be detected precisely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a document size detection device for a copying machine or the like.

[Conventional technology]

As shown in FIG. 3, conventionally, in a copying machine, a document size detection device that automatically detects the size of a document 2 set on a table glass 1 has light emitting elements 3a and 3b mounted on one side of the table glass 1. and the light receiving elements 4a and 4b are arranged on the other side, so that the optical axes 11' and 12' that go from the light emitting elements 3a and 3b to the light receiving elements 4a and 4b along the table glass 1 are It is detected whether or not the optical axis x1' is blocked, and if only the optical axis x1' is blocked, the size of the original 2 is A1 optical axis 7!1' and! 2' was blocked, the size of the document 2 was determined to be B, etc.

[Problem that the invention seeks to solve]

However, in the above device, FIGS. 4(a) and (
As shown in b), when the original 2 is a sheet-like original or book with folds, a part of the original 2 tends to be lifted from the table glass 1. When the optical axis β' toward the light-receiving element 4 passes through the raised part of the original 2, the optical axis β'
Even though the original 2 is present above, it is determined that the original 2 does not exist on the optical axis E', and the size of the original 2 may be incorrectly detected.

[Means for solving problems]

In order to solve the above problems, the document size detection device according to the present invention arranges a light emitting element on one side of a table glass for placing a document and a light receiving element on the other side, and detects the size of a document along the surface of the table glass. In the document size detection device, the document size is detected by detecting whether or not the optical axis from the light emitting element to the light receiving element is blocked by the document. The light-emitting element and the light-receiving element are arranged so as to be inclined with respect to the document placed on the paper.

[For production]

According to the above configuration, the optical axis from the light-emitting element to the light-receiving element is inclined with respect to the direction in which the original is set, so even if a part of the original is lifted off the surface of the table glass, the optical axis is Since the light passes through not only the raised portion of the light but also the portion that is in contact with the table glass, if there is a document on the optical axis, the optical axis will be blocked by the document.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 and 2.

As shown in FIGS. 1(a) and 1(b), a table glass 5 is provided at the top of the copying machine, and a document 6 is positioned and placed on the table glass 5 at an intermediate position in the width direction. It has become. A holder 7 is attached to one side of the table glass 5, and a holder 8 is attached to a position closer to the front than the holder 7 on the other side of the table glass 5. Slings 1-7a and 8 extending in the longitudinal direction of the holders 7 and 8 are located at opposing positions of the holders 7 and 8, respectively.
a is formed.

In the holders 7 and 8, for example, two light emitting elements 9a and 9a are placed.
9b and the light-receiving elements 10a and 10b are connected to each other 7a and 8a.
so that light traveling from the light emitting element 9a to the light receiving element 10a forms an optical axis 11, and light traveling from the light emitting element 9b to the light receiving element 10b forms an optical axis 12 parallel to the optical axis 11. It has become. Note that the light emitted from the light emitting element 9a is not received by the light receiving element 10b, and the light emitted from the light emitting element 9b is not received by the light receiving element 10b.
At point a, no light is received.

The light emitting elements 9a and 9b and the light receiving elements 10a and 10b have optical axes 11 and 12 inclined at a predetermined angle θ with respect to the width direction of the document 6 placed on the table glass 5, and optical axes 11 and E2. is 0.5 to 1 m above the table glass 5
It is positioned so that it passes through a height of m. It is preferable that the angle θ is as large as possible; the optical axis 11 is blocked by the originals 6 of size A and size B;
The - direction optical axis 12 is set to be blocked only by the size B original 6. Note that as the light emitting elements 9a and 9b, for example, light emitting diodes are used, and the light receiving element 1
For example, phototransistors are used as 0a and 10b.

In the above configuration, when the original 6 is placed on the table glass 5, the light emitting elements 9a and 9b alternately emit light, and the optical axis 11 extends from the light emitting element 9a to the light receiving element 10a.
If only the size of the original 6 is blocked by the original 6, it is detected that the size of the original 6 is A, and on the other hand, the size of the original 6 is detected to be A.
If both the optical axis 11 heading toward
It is detected that the size of is B. Note that, as described above, since the two light emitting elements 9a and 9b emit light alternately, for example, in the unlikely event that light from the light emitting element 9a is received by the light receiving element 10b. Even if there is, the received light is sent to the light emitting element 9b based on the timing of light reception.
Since it is determined that the original is not from the original, there is no adverse effect on the detection of the document size.

Furthermore, since the optical axes 11 and 12 are inclined with respect to the original 6 on the table glass 5, a part of the original 6 is removed from the surface of the table glass 5, as shown in FIGS. 2(a) and 2(b). Even if it is floating, as long as the optical axis β from the light emitting element 9 to the light receiving element 10 crosses the top of the original 6, the optical axis l
passes not only the raised part of the original 6 but also the part that is in contact with the table glass 5, so the optical axis l is blocked by the original 6, and as a result, the optical axis ! It is now possible to accurately detect whether or not the image is crossing over the document 6.

In addition, in embodying the present invention, the light emitting elements 9a and 9
b and the number of light-receiving elements 10a and 10b can be arbitrarily changed depending on the number of document sizes, etc., and the reference position when setting the document 6 on the table glass 5 can also be arbitrarily set.

〔Effect of the invention〕

As described above, the document size detection device according to the present invention arranges a light emitting element on one side and a light receiving element on the other side of a table glass for placing a document, and moves the light emitting element to the light receiving element along the surface of the table glass. In a document size detection device that detects the document size by detecting whether or not an optical axis toward the document is obstructed by the document, the optical axis from the light emitting element to the light receiving element is inclined with respect to the document placement direction. It has a structure in which a light emitting element and a light receiving element are arranged.

As a result, the optical axis from the light-emitting element to the light-receiving element is tilted with respect to the direction in which the original is set, so even if a part of the original is lifted off the table glass, the optical axis is not limited to the raised part of the original. , it also passes through parts that are in contact with the table glass, so if there is an original on the optical axis, the optical axis will be blocked by the original, and as a result, the original size can be detected accurately. It has the effect of becoming

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, FIGS. 1(a) and 2(b) are a schematic plan view and a schematic vertical sectional view, respectively, and FIGS. 2(a) and (b) ) are a schematic plan view and a schematic vertical cross-sectional view, respectively, showing a case where a part of the original is lifted from the table glass, and Fig. 3 (a) and (b).
are a schematic plan view and a schematic vertical cross-sectional view of the conventional example, and the fourth
Figures (a) and (b) are a schematic plan view and a schematic longitudinal cross-sectional view, respectively, showing a conventional example in which a part of a document is lifted off a table glass. 5 is a table glass, 6 is a document, 9a and 9b are light emitting elements, 10alOb is a light receiving element, 7! i12 is the optical axis. Patent applicant: Sharp Corporation (Figure 1)
a) Figure 1 (b) 2nd f! f(a) Figure 2(b) 3rd t! ! (a) Figure 3 (b) Figure 4 (a) Figure 4 (b)

Claims (1)

[Claims] 1. A light emitting element is arranged on one side of a table glass for placing an original, and a light receiving element is arranged on the other side, so that the optical axis from the light emitting element to the light receiving element along the surface of the table glass is aligned with the original. In a document size detection device that detects the document size by detecting whether or not the document is obstructed by A document size detection device characterized in that a light-emitting element and a light-receiving element are arranged.