JPH10194525A - Recording medium detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To excellently operate a recording medium detecting device with simple constitution without increasing the size of the device by interposing a flexible light transmitting member which is a light transmission passage between a light emitting element and a light receiving element to make the part between the light transmitting member and the light emitting element or the light receiving element a paper sheet feeding passage. SOLUTION: A recording medium detecting device (a) arranged on a paper sheet feed unit 3 mainly comprises a light emitting element 202, a light transmitting member 201, and a light receiving element 205. The light emitted from the light emitting element 202 is transmitted to the light transmitting member 201 through a carrying passage 4, and transmitted to the light receiving element 205 provided in a side dead space in an image forming device 1 while transmitted in a refracted manner. The layout in which the light receiving element 205 is arranged in the dead space can be freely obtained without arranging the light emitting element 202 and the light receiving element 205 in the vertical direction, and the device is miniaturized with simple constitution. In addition, the excessive wiring need not be arranged in a main substrate 206, but can be arranged close to the main substrate 206 through free layout of the light transmitting member 201.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a recording medium detecting device for discriminating the presence or absence of a recording medium such as paper in an image forming apparatus such as a printer.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a facsimile, a pudding, and the like, a toner image is formed on a predetermined carrier and then transferred to the surface of a recording medium. Normally, this transfer is performed by transferring a recording medium to a transfer unit and transferring the recording medium to the recording medium.However, if the recording medium is not performed normally, such as when the recording medium is not conveyed to the transfer unit, there is a high possibility that a jam has occurred. It is necessary to detect this situation quickly and take countermeasures. As a countermeasure, for example, a recording medium detection device that optically detects the presence or absence of a recording medium from a light emitting element and a light receiving element has been proposed.

[0003]

However, in such a device, it is necessary to make the light emitting element and the light receiving element as close to each other as possible and to perform a shielding treatment so as to be distinguished from external light in order to secure the light receiving accuracy of the light receiving element. Therefore, it was unavoidable to increase the size of the recording medium detecting device.

In order to avoid an increase in size, it is conceivable to embed a light receiving element and its circuit board in a housing on a conveyance path for a recording medium. In addition to the complexity in terms of assembly, it is necessary to pull out a plurality of bundled wires, called harnesses, to the main board in order to send and receive signals from the main board of the device. There was a problem at the time. The present invention has been made in view of the above points, and an object of the present invention is to provide a recording medium detection device that can be favorably operated with a simple configuration without increasing the size of the device.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a recording medium detecting method for detecting the presence or absence of a recording medium supplied from a paper feed path by receiving light from a light emitting element by a light receiving element. In the device, a bendable light-transmitting member serving as a light transmission path is interposed between the light-emitting element and the light-receiving element, and a sheet-feeding path is formed between the light-transmitting member and the light-emitting element or the light-receiving element. The present invention provides a recording medium detection device characterized by the following. Because the light-transmitting member is bendable according to the present invention, it can be pulled out to the vicinity of the main substrate, and not only is unnecessary harness unnecessary, but also a circuit board for light detection can be formed in the dead space of the device. The device can be downsized.

The light transmitting member may be made of a hard or soft resin, and the light transmission path of the light transmitting member may be provided by a shielding means. As a result, the above-mentioned object can be achieved even with an inexpensive acrylic resin or the like. Furthermore, even if the light transmitting member is formed of an optical fiber, light from the light emitting element can be formed with almost no light loss, and good detection is possible.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall explanatory diagram focusing on a recording medium detection device of an image forming apparatus. In FIG. 1, reference numeral 1 denotes an apparatus main body such as a printer, and a recording medium 101 passing through an internal arrow is transported one by one by a paper feed roller 5 from a paper feed cassette 2 formed in a paper feed unit 3. Is supplied to the transfer unit 6 through the recording medium detection device A.

[0008] The structure of the paper feed unit 3 is an integral frame made of resin, and the recording medium detecting device A is provided. As shown in FIG. 2, the recording medium detecting device mainly includes a light emitting element 202, a light transmitting member 201, and a light receiving element 205, and emits light emitted from the light emitting element 202 through the transport path 4. The light is transmitted to the light receiving element 201 provided in the dead space on the side of the image forming apparatus 1 while refracting and transmitting the light.
5 is processed into an electric signal by a photoelectric conversion circuit (not shown) provided on a control board 203 for controlling the driving of the image forming apparatus 5 and transmitted to a main board 206 for controlling the entire image forming apparatus 1.

As the light transmitting member 201, an optical fiber is preferably used. In this case, the diameter of the optical fiber is 3 to 6 mm
Is used, and a glass having a low refractive index is provided outside glass fibers. The light traveling at an angle close to the axial direction of the optical fiber is totally reflected at the boundary surface, and the light from the light emitting element 201 can be transmitted to the light receiving element 205 with almost no loss.

On the other hand, the light transmitting member 201 is not limited to the optical fiber, but may be made of inexpensive hard or soft acrylic resin or polyester resin. In this case, as shown in FIG. 2, the optical transmission path is shielded by being embedded in the frame of the sheet feeding unit 3 and each outlet is covered with a rib 204 (shielding means).

The transport path 4 for passing the recording medium 101 of the present invention is formed between the light emitting element 202 and the light transmitting member 201, but is not limited to this. You may comprise so that the conveyance path 4 may come in between.

[0012]

According to the present invention, a bendable light-transmitting member serving as an optical transmission path is interposed between a light-emitting element and a light-receiving element, and the space between the light-transmitting member and the light-emitting element or the light-receiving element is supplied. By forming it as a paper path, the light-emitting element and the light-receiving element are not necessarily arranged vertically, the light-receiving element can be arranged in the dead space, the layout can be freely set, and the apparatus can be miniaturized with a simple configuration.

Further, various remarkable effects can be obtained such that the extra wiring is not brought to the main board for controlling the whole of the image forming apparatus and the light transmitting member can be arranged near the main board only by freely laying out the light transmitting members. Can be

[Brief description of the drawings]

FIG. 1A is an explanatory view of an entire configuration, and FIG. 1B is a partially omitted explanatory view of an AA cross section.

[Explanation of symbols]

 A: Recording medium detecting device 1: Printer main body 2: Paper feed cassette 3: Paper feed unit 101: Recording medium 201: Light transmitting member 202: Light emitting element 203: Control circuit board 204: Rib 205: Light receiving element 206: Main substrate

Claims (3)

[Claims] 1. A recording medium detecting device for receiving light from a light emitting element by a light receiving element and detecting the presence or absence of a recording medium supplied from a paper feed path, wherein an optical transmission path is provided between the light emitting element and the light receiving element. A recording medium detecting device, wherein a bendable light-transmitting member is interposed, and a paper feed path is formed between the light-transmitting member and a light emitting element or a light receiving element. 2. The recording medium detecting device according to claim 1, wherein said light transmitting member is made of a hard or soft resin, and said light transmission path of said light transmitting member is provided by shielding means. . 3. The recording medium detecting device according to claim 1, wherein said light transmitting member is constituted by an optical fiber.