JP2867646B2 - Device for determining the size of paper etc. - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for determining the size of a sheet or the like represented by a document size determining device used in a copying machine.

Conventional technology and its problems Conventional document size discriminating devices installed in copiers include:
There are a type in which a pre-scan is performed using a photoelectric sensor as shown in FIG. 11 and a type in which a proximity switch or the like is built in an upper cover of the copying machine as shown in FIG.

In FIG. 11, a movable arm 53 is provided inside a copying machine 50, and a large number of reflective photoelectric sensors 54 are mounted on this arm 53. Before the copying operation, the movable arm 53 moves and the original on the glass plate 51 is scanned by the photoelectric sensor 54 (pre-scan), and the size of the original is determined based on the output signal of the photoelectric sensor 54 at this time. This type has the advantage of being able to determine the size of various types of originals. However, the presence of movable parts makes the entire device larger and the mechanism is more complex. However, there is a problem that the time is lost and quick copying cannot be performed.

In FIG. 12, a plurality of proximity switches (for example, photomicro sensors, etc.) 55 are built in the upper lid 52 of the copying machine 50. When a document is placed on the glass plate 51 and the top cover 52 is closed, each proximity switch 55 detects the presence or absence of the document at the mounting position of the proximity switch, and a plurality of proximity switches are detected.
The document size is determined based on the 55 detection signals. This type has the advantage that it can save space compared to the prescan type shown in FIG. However, because the sensor is located on the top cover, the size of the original cannot be determined without the top cover. It cannot be applied to a copier that has an automatic drive feed (ADF) function. As a result, there is a problem that a pressing mark remains on the original, and when the copy paper size is larger than the original size, a shadow of a sensor that is not hidden by the original is reflected on the copy paper.

Further, there are generally two types of document arrangement in a copying machine. It is center alignment and unalignment. When the sensor is aligned, the center line of the document (generally a line passing through the center in the width direction, but sometimes a line passing through the center in the length direction) is aligned with the center line of the glass plate 11 (generally in the optical scanning direction). The document is arranged such that one end of the document coincides with one end of the glass plate (perpendicular to the center line). On the other hand, in the alignment, the document is arranged such that two adjacent and orthogonal sides of the document are on two adjacent and orthogonal sides of the glass plate.

In order to determine the size of the original in both the center alignment and the alignment alignment, a considerably large number of sensors are required.

SUMMARY OF THE INVENTION An object of the present invention is to provide a paper size discriminating apparatus which is small in size, has high-speed response, can be detected without an upper cover, and can be used commonly for arranging two or more different types of paper. To provide.

Configuration, operation, and effect of the present invention A paper size determining apparatus according to the present invention includes a first photosensor for determining the size of a sheet and a second photosensor for determining an arrangement position of the sheet. It has. The first photosensor includes a multi-beam light source for projecting a plurality of light beams to different places according to the size and position of a sheet to be discriminated, and a plurality of reflections from the sheet to be discriminated regarding the plurality of light beams. It comprises a plurality of light receiving elements for receiving light beams, respectively, and an imaging optical system for guiding the plurality of reflected light beams to the corresponding light receiving elements. Then, based on a combination of the output signal from the light receiving element of the first photosensor and the output signal of the second photosensor, the size of the sheet disposed at any one of at least two positions is determined. .

When the present invention is applied to determine the size of a document in a copying machine, the two arrangement positions are, for example, a center alignment position and a half alignment position.

If there is an overlapping portion between the two arrangement positions, in the overlapping portion, the projection positions of the plurality of light beams of the first sensor are determined in consideration of the size and position of the sheet to be determined. The light beam can be used for discriminating the size of the paper at both positions, and the number of beams can be reduced accordingly. In the present invention, the size of the sheet is determined by a combination of the output signals of the plurality of light receiving elements of the first photosensor and the output signal of the second photosensor. Paper can be detected, and the number of light beams need not be so large.

According to the present invention, the multi-beam light source, the plurality of light receiving elements, and the imaging optical system of the first photosensor can be integrated, and the size can be reduced because there is no movable part. In addition, since no pre-scan operation is required, high-speed response is provided. Furthermore, when the discriminating device of the present invention is applied to a copying machine, it is not necessary to provide the disc on the top cover.
The size of the paper can be determined without the top cover, and the present invention can be applied to a copying machine having an automatic paper feeding function. In addition, there is no problem that a pressing mark remains or a shadow appears.

The multi-beam light source may include a light-emitting element and an off-axis Fresnel lens array including a plurality of off-axis Fresnel lenses that divides light emitted from the light-emitting element and deflects the light in different directions. it can. With such a configuration, the size of the multi-beam light source can be reduced.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment in which the present invention is applied to a document size discriminating apparatus used in a copying machine will be described in detail.

This embodiment relates to a document size discriminating apparatus which is commonly used for discriminating the sizes of a center-aligned document and a half-aligned document.

In FIG. 1, a photo sensor (first photo sensor) 20 for discriminating a document size is arranged at an appropriate position inside the copying machine 10. The copier 10 has its upper surface covered with a glass plate 11,
Documents 12 of various sizes to be copied are placed at predetermined positions on the glass plate 11 (there are a center alignment position and a half alignment position). Photosensor 20 projects light beams of a plurality (five in this example) toward different positions P _a within the location where the document 12 on the glass plate 11 is placed, P _b, P _c, the P _d and P _e Then, by receiving reflected light from the glass plate 11 or the original 12, the original size is determined or a detection signal for the determination is output.

A photosensor (second photosensor) 15 for judging whether the original placed on the glass plate 11 is centered or unaligned is provided inside the copier 10. Are located. The photo sensor 15 is, in principle, a light beam at a position where the original at the alignment position is detected and the original at the center alignment position is not detected (a large-size original is detected at any alignment position in this embodiment). Is arranged at a corner in the copying machine 10 so as to project the image.

FIG. 2 shows an example of the configuration of the photo sensor 20 for document size discrimination. The photo sensor 20 has a case 29 in which the multi-beam light source 21, the imaging lens 22, and the light receiving element array 23 are arranged and fixed. The multi-beam light source 21 is provided with a light-emitting element, for example, a light-emitting diode 24 for generating light including infrared light, and is disposed above the light-emitting diode 24, divides the light emitted from the light-emitting diode 24 into five light beams, and And an off-axis micro-Fresnel lens array 25 for projecting toward different positions. The light receiving element array 23 has many light receiving elements. In this embodiment, only five light receiving elements are used. It goes without saying that only the number of light receiving elements to be used may be arranged in the light receiving element array 23. As will be described later, the imaging lens 22 mainly diffuses the projection light beam from the document 12 and generates diffused light (diffusely reflected light).
Is formed on the corresponding light receiving element.
On the upper surface of the case 29, a visible light cut filter 2 is provided at a position above the multi-beam light source 21 and the imaging lens 22, respectively.
6,27 are provided. In this embodiment, infrared light is used for discriminating the document size.

Off-axis micro Fresnel lens array
FIG. 3 shows 25 configuration examples. The lens array 25 includes a plurality (three in this embodiment) of off-axis lenses.
Micro Fresnel lenses (hereinafter abbreviated as off-axis MFL) 25a, 25b and 25e are arranged in a predetermined arrangement. As shown in Fig. 6, the off-axis MFL deflects the incident light beam in a desired direction and collimates the diffused light according to the shape of the unequally-spaced grating formed thereon. Can also). Such off-axis MFL25a, 2
5b and 25e have grating patterns in which a part of the micro Fresnel lens is cut out.

Using off-axis MFL array 25 shown in Figure 3, divides the output light beam of the light emitting element 24 into five and collimates the beam spot _{P a, P b, P c} , the P _d and P _e glass It can be made on the plate 11 at a position as shown in FIG. That is, the beam spot P _a and P _d is made by the ± 1-order diffracted light of the off-axis MFL25a. Beam spot by ± 1st order diffracted light of off-axis MFL25b
P _b and P _c is formed. Then, the beam spot P _e is generated by the off-axis MFL25e.

Off-axis MFL arrays other than those shown in FIG.
Respectively to be formed beam spot P _a to P _e corresponds can be employed those having five off-axis MFL.

FIGS. 4, 5 and 7 to 10 show the principle for determining the size of the center-aligned and unaligned originals using the photosensors 20 and 15 described above.

As described above, the light spreads emitted from the light emitting element 24 is divided into five light beams by the off-axis MFL arrays 25, and is collimated, a glass plate with a beam spot P _a to P _e of suitable area 11 or The document 12 is irradiated.

As shown in FIG. 7, the light illuminated on the original 12
Diffusely reflected by 12. That is, the brightness of the spot on the document 12 is substantially constant from any direction.
On the other hand, the reflection on the front surface and the rear surface of the glass plate 11 is close to the specular reflection, and as shown in FIG. 8, the component of the reflected light (specular reflected light) having the reflection angle α equal to the incident angle α increases. .

The light receiving element array 23 has a glass surface as shown in FIG.
It is arranged at a position where it does not receive the regular reflection light from 11. Thus, five light-receiving element PD _a -PD _e of the light-receiving element array 23 will be able to detect the diffuse light from the document 12.

An imaging lens 22, a weak diffusion light from the original 12 is condensed, respectively of the beam spot _{P a, P b, P c} , P d, receives diffuse reflected light from the P _e element array 23 Light receiving element PD _a ,
It functions to form an image on PD _b , PD _c , PD _d , and PD _e .

The photo sensor 15 also includes an optical system including a light emitting element and a light receiving element that can detect the presence or absence of a document. The optical system of the photo sensor 15 is also configured so as not to receive the specularly reflected light from the glass plate 11. A normal reflection type photoelectric sensor may be used. The projected light beam spot of the photosensor 15 is in the Figure 9 are shown as P _o. Further, the light receiving element of the photo sensor 15 and PD _o.

FIG. 9 shows originals of various sizes arranged on the glass plate 11. What is indicated by a solid line is the center alignment. The center-aligned document has its center line (a line passing through the center in the width direction or the length direction) coincident with the center line CL of the glass plate 11 and one end of the document is so arranged on one end of the glass plate 11. . There are seven types of document sizes A5, B5, A4, B4, A3, B5R and A4R for which the center alignment is determined. B5R
The A4R and the other A5-A3 have the vertical and horizontal arrangement reversed.

What is indicated by a chain line is a combination. Triangular hatching is applied to one corner of the original so that the originals can be clearly seen. A two-sided manuscript has two adjacent sides.
The glass plate 11 is arranged along two predetermined adjacent sides. B5, A
There are six types: 4, B4, A3, B5R and A4R.

In this embodiment, by using the diffused reflected light from a single light beam spot P _o from five optical beam spot P _a to P _e and the photo sensor 15 from the photosensor 20, seven of the center combined It is possible to discriminate between six types of original sizes, i.e., original size and union. Multi-beam light source 21 and the photo sensor 15 of the photo sensor 20 so that each beam spot P _a to P _e and P _o in relation to these document of each size is formed at a position as shown in FIG. 9 is Adjusted.

Figure 10 is placed a combined position (center combined, Kataawase) shows the relationship between the size of and the document, and the output of the light receiving element PD _a -PD _e and PD _o receives diffuse reflected light from the original is there. Receiving signal of the light receiving element PD _a -PD _e and PD _o is the level discrimination with a suitable threshold, respectively, L level or H
It is converted to a level binary signal. The L level indicates a state where the document is not detected, and the H level indicates a state where the document is detected. These original size in accordance with a combination of the level of the output signal of the six light receiving element PD _a -PD _e and PD _o that is determined easily understood. The determination process of the document can be performed by a logic circuit or a CPU.

As can be seen from FIG. 10, the output signal of the light receiving element PD _a -PD _e is shared in both the center together and Kataawase. The output signal of the light receiving element PD _o not only detection of Kataawase document, is also used for the determination of the center combined document.

In the above embodiment, as can be seen from FIG. 9, A3 and A4R
The positions of the originals of the size are almost the same in center alignment and unalignment. However, this embodiment can be applied even when these originals A3 and A4R are located at different positions for center alignment and single alignment.

In this way, the size of the original placed at the center alignment position and the alignment position can be determined using the same optical system, and the number of light emitting and light receiving elements in the optical system can be determined. Very little.

The above-described off-axis MFL array 25 can be manufactured by various methods. For example, a pattern of an off-axis MFL array is drawn on an electron beam resist by an electron beam drawing method, and the electron beam resist is developed. A stamper is formed by an electroforming method, a transfer method, or the like from the off-axis MFL array pattern formed by the electron beam resist remaining film thus obtained. Using this stamper, a large number of off-axis MFL arrays can be copied at low cost by a resin molding method or the like.

As a projection lens of the multi-beam light source, not only an off-axis MFL array but also a plano-convex lens array or an aspherical lens array can be used. These lens arrays can be molded using a mold or the like.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a state in which a photosensor for document size discrimination and a photosensor for alignment position discrimination are built in a copying machine. FIG. 2 is an enlarged perspective view, partially cut away, showing the configuration of the photosensor for document size discrimination. FIG. 3 is a plan view showing an off-axis micro-Fresnel lens array in the original size discrimination photosensor. 4 and 5 show the configuration of the light projecting and receiving optical systems in the photo sensor for document size discrimination. FIG. 4 is a plan view and FIG. 5 is a side view. FIG. 6 is a perspective view showing the operation of the off-axis micro Fresnel lens. FIG. 7 is a diagram showing a state of diffuse reflection from a document surface, and FIG. 8 is a diagram showing a state of regular reflection from a glass surface. FIG. 9 is a diagram showing the relationship between the beam spot position and various document sizes at both the center alignment and the alignment. FIG. 10 shows the document size discrimination logic based on the output signal of the light receiving element. 11 and 12 are perspective views showing a conventional example. 10 ... Copier, 11 ... Glass plate, 12 ... Document, 15 ... Photosensor for discriminating position, 20 ... Photosensor for discriminating size, 21 ... Multi-beam light source, 22 ... Imaging lens , 23 ... Light receiving element array, 24 ... Light emitting element, 25 ... Off-axis micro-Fresnel lens array, 25a, 25b, 25e ... Off-axis micro-Fresnel
Lens, PD _{a to} PD _e , PD _o ... Light receiving element, P _{a to} P _e , P _o ... Projected light beam spot.

Continuation of the front page (72) Inventor Yukio Hattori 10-store, Hanazono Todocho, Ukyo-ku, Kyoto-shi, Kyoto Omron Corporation (56) References JP-A-3-175306 (JP, A) JP-A-63-132566 (JP) , A) JP-A-61-155904 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01B 11/00-11/30 G03B 27/62 G03G 15/04

Claims (3)

(57) [Claims] A first photosensor for judging a size of a sheet; and a second photosensor for judging an arrangement position of the sheet, wherein the first photosensor includes a plurality of light beams. A multi-beam light source for projecting to different places according to the size and position of the paper to be determined, and a plurality of light receiving elements for receiving a plurality of reflected light beams from the paper to be determined regarding the plurality of light beams, respectively And an imaging optical system that guides the plurality of reflected light beams to the corresponding light receiving elements. A combination of an output signal from the light receiving element of the first photo sensor and an output signal of the second photo sensor is formed. A size discriminating device for discriminating a size of a sheet disposed at any one of at least two positions based on the size of the sheet. 2. The apparatus according to claim 1, wherein said two arrangement positions are a center alignment position and a half alignment position. 3. A multi-beam light source, comprising: a light-emitting element; and an off-axis Fresnel lens array including a plurality of off-axis Fresnel lenses that divides light emitted from the light-emitting element into a plurality of light beams and deflects the light in different directions. The apparatus for determining the size of a sheet or the like according to claim 1 or 2, wherein the apparatus comprises: