JPS58130832A - Paper width detector - Google Patents

Abstract

PURPOSE:In a copying machine or the like, to enable paper width detection with a small detected position error, by providing an optical detection sign on the surface of at least one of a pair of racks fitted with guides on which paper is set. CONSTITUTION:A detection sign 9 different in reflectivity from the other portion of a rack 3 is provided on the surface of the rack so that the sign is located in a prescribed position. A reflection-type photosensor 8 is mounted in a position to face the detection sign 9. The position of the sign 9 is detected with the accuracy of several tenths of millimeter depending on the size of paper positioned by a right and a left guides 5, 6. In that case, two sizes of paper can be detected by the sign 9. If two detection signs 9-1, 9-2 and corresponding photosensors are provided, three sizes of paper can be detected. If the two signs 9-1, 9-2 are displaced in the direction of movement of the rack 3, four sizes of paper can be detected. Since optical detection is thus effected, paper width detection with a small detected position error is enabled.

Description

[Detailed Description of the Invention] The invention relates to a device for detecting the width of paper loaded in a printer, a copying machine, etc., and in particular a device for detecting the width of paper loaded in a paper tray equipped with an adjustable (movable) guide. This relates to the paper width detection value $1l11C.

A top view and an h-AllllFi side view of a paper tray with an adjustable guide for a printer or the like according to the prior art are shown in 4.
Shown in Figures 1 and 2.

In these figures, 1 is a paper tray, 2 is a pinion gear, and 6 and 4 are @ engaged with the pinion gear 2.
Rack gears 1 and M2, 5 and 6 are the left and right guides connected to the first and wi2 rack gears 6.4, respectively. 7 is a rack gear (in this example, a rack gear) connected to one of the guides (in this example, the left guide 5). This is a microphone switch.

As is clear from the figure, the 111 easy gear 5° second rack gear 4 fixed to the left guide 5 and the right guide 6 meshes with the pinion gear 2, so the left guide 5 and the right guide 6 are connected to each other as indicated by the arrows. 5, it moves symmetrically with respect to the pinion gear 2 in the width direction of the paper.

Therefore, when paper (not shown) is placed between the left and right guides 5.6, the left and right guides 5.
．． The position of 4 is uniquely determined according to the paper width.

Therefore, if the relative position between the notch 5B of the first rack gear and the first microswitch 7 is appropriately set to i, the width of the loaded paper can be detected by turning the microswitch 7 on and off.

However, conventional paper width detection devices have the following drawbacks.

(1) Because there are manufacturing variations in the microswitch itself, it takes a long time and skill to adjust key 11, such as the * position.

--) It is necessary to provide sloped portions as shown in the figure at both ends of the notch MB. For this reason, the micro switch 7
The operating position (therefore, the detection width of the paper) results in a deviation of K number ■. Therefore, for example, a detection error may occur between A4 size (210-width) paper and letter legal (216-inch width) paper.

SUMMARY OF THE INVENTION An object of the present invention is to improve the drawbacks of the prior art described above and to provide a paper width detection mechanism in which the deviation of the detection position due to the moving direction of the guide is small.

In order to achieve the above object, in the present invention, at least one of the first and second racks is provided with a detection mark having different optical characteristics from the other parts, and this mark is optically detected. I'm using 5K to detect the width.

The invention will be explained below with reference to one drawing. FIG. 3 is a top view of an embodiment of the present invention, and FIG. 4 is a sectional view taken along the line A-AmK. In these figures, the same reference numerals as in Figures 1B1 and 2 refer to the same or equivalent parts.

In the figure, 8 is a reflection J including a light emitting element and a light receiving element.
17 Otosensor 9 is a detection mark provided at a predetermined position on the surface of the rack gear 60 and has a different reflectance from other parts. The detection mark 9 is arranged at a predetermined position on the surface of the rack gear 6.

Furthermore, the reflective photosensor 8 can be mounted with high accuracy at a planned relative position facing the reflective photosensor 8.

(As is known, photosensors are essentially [1
The position can be detected with an accuracy of 0/0, and the detection mark 9
Since there is no detection error due to the moving direction of the left and right guides 5.
It is possible to detect the dimensions of the paper loaded between 6 and 6 with the same degree of accuracy.

In addition, although a reflective flea sensor was used in the above, it is obvious that a transmissive type sensor may also be used. Further, although the above description has been made of the case where one detection mark is provided and two types of paper sizes are detected and discriminated, it is clear that the present invention is not limited to this.

In other words, for example, two sets of detection marks as shown in Fig. 5? -1, 9-2 and corresponding photosensors (not shown) are provided, five types of paper sizes can be detected by combining the outputs of the seven photosensors in the areas ←), (b), and (c). , can be determined.

Also, as shown in FIG. 6, two sets of detection marks 9-1 and 9-2 are placed in each area in the moving direction of the rack gear 6. Four types of paper sizes can be detected and discriminated by the combination of the outputs of the photosensors.

In addition, when providing a plurality of detection marks, it is clear that they may be provided separately on a pair of rack gears 3.4.

[Brief explanation of the drawing]

FIG. 1 is a top view of a conventional paper width detection device, FIG. 2 is a sectional view taken along the line A-A, and FIG. 6 is a top view of an embodiment of the present invention. Cross-sectional view on the line, Sakae, 61
21 + 2 test = 4 tons of Mar 2 A)・1) There is a diagram of 1. 1...Paper tray, 2...Pinion gear,
6...1st rack gear, 4...ls2 rack gear, 5...left guide, 6...right guide, 8
...Reflective type 7 odosensor, 9...Detection mark agent Michi Hiraki

Claims (1)

[Claims] (1) A paper tray for placing paper, a pair of rack gears that can move in a direction perpendicular to the running direction of the paper and in opposite directions, and a rack gear that is fixed to each of the rack gears and is perpendicular to the paper transport surface. and a pair of guides having upright surfaces parallel to the paper conveyance direction and between which the paper is placed, an optical detection mark provided on at least one surface of the rack gear, and a pair of guides facing the rack gear. 1. A paper width detection device characterized by comprising a photo sensor set to detect the presence or absence of the mark.