JPS61182589A - Paper detector - Google Patents

Abstract

PURPOSE:To detect paper easily by forming at least a part corresponding to an infrared sensor out of a paper guide plate by a member for passing infrared rays and shielding visual light rays. CONSTITUTION:An original P is fed along a paper guide 11 by rollers 5-7. A transmission type infrared-ray sensor 14 consisting of a light emitting element 12 and a photodetecting element 13 which are oppositely arranged through the plate 11. The plate 11 is formed by a member, e.g. transparent resin mixed with a violet dye, for passing infrared rays and shielding visual light rays. When the original P does not exist, infrared rays radiated from the element 12 are transmitted through the plate 11 and made incident upon the element 13, and when the original P exists, the infrared rays are not made incident upon the element 13, so that the existence of the original P can be detected. Since the late 11 passes the infrared rays and shields the visual light rays, the element 13 does not receive the visual light rays and is prevented from misdetection. Thus, the original P can be detected without interrupting the carrying of the original P.

Description

[Detailed description of the invention] Kisaku” The present invention relates to a single paper detection device.

2. Description of the Related Art Conventional technologies such as facsimile machines, image scanners, printers, etc. are equipped with a paper detection device that detects the presence or absence of a document, recording paper, or the like.

For example, as shown in FIGS. 5 and 6, a conventional paper detection device includes a paper guide plate 1 that guides one sheet of paper P, and a transmission type photosensor 4 (a fifth
(Example shown in FIG. 6) or a reflective photosensor 4' (Example shown in FIG. 6).

In such a paper detection device, a through hole 1a is formed in the paper guide plate 1 in order to form an optical path for a photosensor.

However, if the paper guide plate is provided with through holes in this way, there is no problem when the paper is in good condition.

When the paper is curled, the leading edge of the paper may interfere with the through hole of the paper guide plate, resulting in a paper jam, as shown by the two-dot chain line in both figures.

Purpose This invention has been made in view of the above points, and an object thereof is to enable detection of the presence or absence of paper without interfering with the conveyance of paper.

1-1 In order to achieve the above-mentioned object, the present invention is such that at least the portion of the paper guide plate corresponding to the infrared light sensor is formed of a member that allows infrared light to pass through and blocks visible light.

Hereinafter, a detailed explanation will be given based on one embodiment of the present invention.

FIG. 1 is a schematic diagram of a document feeding section of a facsimile machine equipped with a paper detection device embodying the present invention.

This document feeding section feeds the document P along the paper guide plate 11 using rollers 5, 6.7.

A transmission-type infrared light sensor (photosensor) 14 is provided, which includes a light emitting element 12 such as an infrared light emitting diode and a light receiving element 16, which are arranged facing each other with a paper light plate 11 interposed therebetween.

The paper guide plate 11 is made entirely of a member 1 that allows infrared light to pass through and blocks visible light, such as a transparent resin mixed with purple dye.

As a result, as shown in FIG. 2, the emitted light (infrared light) emitted from the light emitting element 12 passes through the paper guide plate 11 and enters the light receiving element 13 when the original P is not present. At certain times, the light is not incident on the light receiving element 13, so
The presence or absence of the document P can be detected.

In this case, the paper power plate 11 allows infrared light to pass through and blocks visible light, so that the light receiving element 13 does not receive visible light and no erroneous detection occurs.

In this way, the paper guide plate of this paper detection device has a document P.
Since no through holes are formed that would obstruct the conveyance of the document P, paper jams will not occur even if the document P is curled or the like.

In addition, by forming the entire guide plate with a material that allows infrared light to pass through and blocks visible light as in this embodiment, it is no longer necessary to form through holes in the single paper guide plate, reducing manufacturing man-hours and costs. Decrease.

FIG. 3 is a schematic diagram of a recording paper feeding section of a facsimile equipped with a paper detection device embodying the present invention.

This recording paper feeding section prints on the recording paper P pulled out from the roll paper 15 along the paper guide plate 21 with the thermal head 16, and sends it out with the roller 17.

A reflective infrared light sensor 24 consisting of a light emitting element that emits infrared light and a light receiving element is arranged below the paper guide plate 21.

The paper guide plate 21 is as shown in FIG.

A portion 21a corresponding to the infrared light sensor 24 is formed of a member that allows infrared light to pass through and blocks visible light.

Thereby, as shown in FIG. 4, the infrared light sensor 22
The emitted light (infrared light) emitted from the light-emitting element passes through the paper guide plate 21 when there is recording paper P, is reflected by the recording paper P, and enters the light-receiving element, and when there is no recording paper P, Since the light passes through the guide plate 21 and does not enter the light receiving element, the presence or absence of the recording paper P can be detected.

In the above embodiments, the case where the paper detection device according to the present invention is used in the document feeding section and the recording paper feeding section of a facsimile machine is described, but the present invention is not limited to this.
For example, it can be used in image scanners, printers, etc.

As explained above, according to the present invention, it is possible to detect a sheet of paper without interfering with its conveyance6.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are a schematic diagram of a document transport section and a diagram of a paper detection device thereof, showing an embodiment of the present invention. 3 and 4 are schematic configuration diagrams of a recording paper feeding unit and a configuration diagram of its paper detection device showing other embodiments of the present invention, and FIGS. 5 and 6 are diagrams showing different conventional paper detection devices. It is a block diagram which shows an example. 11.21... Paper guide plate 12... Light emitting element 13... Light receiving element 14.2
4... Infrared light sensor Figure 1 P Second cause Ear Hi 13 Figure 3 Figure 4

Claims (1)

[Claims] 1. In a paper detection device comprising a paper guide plate that guides paper and an infrared light sensor that detects the presence or absence of paper conveyed on the paper guide plate, at least the infrared light sensor of the paper guide plate A paper detection device characterized in that a portion corresponding to the above is formed of a member that allows infrared light to pass through and blocks visible light.