JPH0836330A - Sheet size detector - Google Patents

Abstract

PURPOSE:To prevent erroneous detection of a sheet size only by altering the contents of sheet size recognition control. CONSTITUTION:An actuator 7 for size detection is provided on the face of the front end of a tray 2 on the insertion side. By moving an operation body 8 in the direction shown by the arrow, the sheet size gradation of the sheet size scale of the actuator 7 is set at a setting position mark put on the upper face of the tray 2 on the insertion side. On the side of the machine main body 1, a plurality of photosensors 12 for sheet size detection are arranged opposite to the intercepting plates 14 of the actuator 7. Sheet size recognition based on the changes of the states of the sensors 12 is inhibited for the prescribed length of time right after the insertion of the tray. Thus, accuracy in the sheet size recognition is improved, and images are formed on the set size of the sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper size detection device such as a copying machine or a printer, and particularly to prevent erroneous detection in paper size detection immediately after insertion of a paper feed tray (hereinafter referred to as tray). The present invention relates to a paper size detection device suitable for.

[0002]

2. Description of the Related Art As a means for detecting a sheet contained in a tray, as shown in FIG. 1 of Japanese Utility Model Laid-Open No. 1-174334, an actuator having an uneven pattern on the insertion leading surface of the tray is used as a sheet size. It is slidable according to the number of push type mechanical switches on the machine body side, and each switch is turned ON / OFF after the tray is inserted.
A method of detecting the paper size by a combination of OFF is generally performed. The tray is guided by the rails and inserted into the machine body, but depending on the finishing accuracy of the parts and the way the operator operates, the left and right sides of the tray may not be inserted at the same time, either one may be inserted with a delay (or ahead). Situation occurs.

[0003]

As described above, since the tray is not always inserted straight into the machine body, the tray insertion leading surface is inclined with respect to the sensor group and should be turned ON. It is possible that the switches will not turn on at the same time. If the detection is executed at this stage, an erroneous ON / OFF combination will be recognized, and the paper size will be erroneously detected. Such a defect is
The same applies to the case where the reed switch and the magnet disclosed in Japanese Utility Model Laid-Open No. 3-118945 are used. Further, when the bush type mechanical switch is used, the ON timing error may occur due to variations in the push pressure or the fatigue of the mechanism in addition to the causes described above, resulting in erroneous detection of the paper size. There's a problem. An object of the present invention is to provide a paper size detection device capable of preventing erroneous detection of the paper size only by changing the content of the paper size recognition control.

[0004]

In order to achieve the above object, the present invention as set forth in claim 1, recognizes the size of a sheet accommodated in a tray by inserting and mounting the tray in a machine body. In the paper size detection device, a detection unit, which is arranged on the machine body side and includes a plurality of detection units, is provided on the tray side facing the detection unit, and is set according to the size of the paper. An actuator that changes the state for each detection unit, and a sheet size recognition unit that detects the size of the accommodated sheet from the combination of the output states of the detection unit are provided, and the sheet size recognition unit is the actuator when the tray is inserted. Has a configuration in which each of the detection units is operated and the size recognition operation is executed after a predetermined time has passed immediately after the output of any of the plurality of detection units.

[0005]

According to the above construction, by controlling so that the determination operation of the state change of the sensor is not performed for a predetermined time immediately after the tray is inserted, the recognition accuracy of the paper size is improved, and the paper of the set paper size is set. An image is formed with respect to.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 shows the tray when it is pulled out. On the front surface of the machine body 1, a tray 2 capable of accommodating various paper sizes is guided by a rail 3 and is detachably mounted. As shown in FIG. 4, paper guides 5 and 6 for aligning the paper 4 at the reference position are provided on the insertion side and one side of the tray. After accommodating the sheet 4 in the tray 2, the sheet guides 5 and 6 are moved in the arrow direction to position the sheet.

An actuator 7 for size detection shown in FIG. 5 is provided on the insertion-side leading surface of the tray, and the operating body 8 is slid to a position corresponding to the size of the accommodated paper by moving in the direction of the arrow. You can set it. The actuator 7 has a set position mark 10 provided on the upper surface of the tray 2 on the insertion side, a sheet size scale 11 on the sheet size scale 9 of the actuator 7,
That is, it is set by aligning the position corresponding to the accommodated paper size. On the other hand, on the machine body side, a plurality of photosensors 12 are arranged at positions facing the actuator 7 as means for detecting the paper size.
The configuration of this paper size detection will be described in detail with reference to FIG.

At the upper end of the tray 2 on the insertion side, there is provided a mounting portion 13 extending along the side edge of a sheet to be accommodated, and an actuator 7 is slidably engaged with and supported by the mounting portion 13. A plurality of shield plates 14 for detecting the paper size are arranged at predetermined intervals on the front surface of the actuator in the tray insertion direction. On the other hand, on the machine body side, the same number of photosensors 12 as the shielding plates are mounted on one substrate 14 so as to face the shielding plate 14 and are arranged in an integrated state. In this example, each of the four photosensors and the shielding plate 14 are used.

The operator stores the paper in the tray, sets the actuator at a predetermined position according to the size of the paper, and then inserts the tray into the machine body. Then
The actuator blocks the optical axis of the photosensor, and an ON / OFF signal is input to the paper size recognition control means as a state change signal of each sensor, and the size of the paper is confirmed by, for example, a combination of four sensor signals.

The paper size recognition control means has the function of recognizing the size by executing the paper size recognition program. The contents of the recognition control are that the tray is inserted into the machine main body and one of the sensors 1 to 4 is first detected. When it is turned on, the operation is performed so that the size recognition is not executed for a predetermined time from that time, for at least 300 mse. In this example, as shown in the size detection reading timing of FIG. 2, after the photo sensor 1 is turned ON for 0 N, the size is not recognized for 500 msec.

The sheet size detecting means may be constituted by the following detecting means in addition to the above embodiment. The detection means is a plurality of mechanical push switches, and the actuator is a convex member that presses each push-in portion of the plurality of push switches. The detection means is a plurality of magnetic reed switches, and the actuator is a magnet that approaches the facing surfaces of the plurality of magnetic reed switches.

[0012]

As described above, according to the present invention, the size recognition operation is executed after a lapse of a predetermined time immediately after the output from any one of the plurality of detection units, so that the instability at the time of inserting the tray becomes unstable. It is possible to prevent erroneous size recognition based on the sensor output in the tray state. This size detection can be dealt with only by the contents of the recognition control, that is, by changing the software, so that the cost is not increased from the conventional method.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of a paper size detection device according to the present invention.

FIG. 2 is a diagram showing a timing of a paper size detection operation.

FIG. 3 is a perspective view showing a usage example of a paper feed tray device to which the present invention is applied.

FIG. 4 is an explanatory diagram showing an operation of a paper guide.

FIG. 5 is a partially enlarged perspective view of a tray for explaining a set of actuators for detecting a paper size.

[Explanation of symbols]

1 ... Machine main body, 2 ... Paper feed tray, 3 ... Tray guide rails, 4 ... Paper, 5, 6 ... Paper guide, 7 ... Actuator, 8 ... Manipulator, 9 ... Paper size scale, 10 ... Set position mark, 12 ... Photo sensor, 14 ... Shielding plate

Claims (1)

[Claims] 1. A paper size detection device for recognizing the size of paper stored in a paper feed tray by inserting and mounting the paper feed tray into a machine body, wherein a plurality of detection units arranged on the machine body side. A detection means, which is provided on the side of the paper feed tray facing the detection means, sets an actuator according to the size of the paper, and changes the state of each of the detection units; and an output of the detection means. Paper size recognition means for detecting the size of the stored paper based on the combination of states; and the paper size recognition means, when the paper feed tray is inserted, the actuator operates each detection part, A paper size detecting device, characterized in that a size recognition operation is executed after a lapse of a predetermined time immediately after any one of the outputs.