JPS61127546A - Recording sheet detector of electrostatic recording apparatus - Google Patents

Abstract

PURPOSE:To prevent malfunction of detecting a paper jam due to bending of a recording sheet by operating recording sheet detecting means plural times in case of recording on one recording sheet, and deciding that a paper jam is not caused when a recording sheet is detected once. CONSTITUTION:A photosensitive drum 2 is rotatably installed in a copying machine body 1, and a paper feed cassette 9 where copy sheets 8 as a recording sheet are loaded is detachably mounted therein. In this case, sensors 12, 24 respectively for detecting the arrival of the copy sheet 8 and actuators 13, 25 for the sensors are disposed on the respective downstream sides of a paper feed guide 11 on the downstream side of a paper feed roller 10 and of a paper feed guide 19 on the downstream side of the photosensitive drum 2. In case of detecting the copy sheet 8 by the sensor 24, for example, a shutter 16 is opened so that the copy sheet 8 starts to move, and then the existence of the copy sheet 8 is detected plural times by the sensor 24. Thus, only in the case where the existence of the copy sheet 8 is not detected at any times, a paper jam signal is output.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a recording paper detection device for an electrostatic recording machine such as a printer, facsimile, or electronic copying machine.

(b) Prior art Conventional electrostatic recording device, for example, Japanese Patent Application Laid-Open No. 57-139765
In the electronic copying machine as disclosed in the above publication, whether or not copy paper (recording paper) has passed is detected only L times by a copy paper detection means. That is, when the copy paper should arrive at the position where the detection means is provided, the detection means described in I is operated only once, and the presence of the copy paper is detected at the time when this detection means is operated. "The only thing that happened was a paper jam."
However, if the presence of copy paper is not detected at that point, it is determined that a paper jam has occurred, and a signal to that effect is output.

(C) Problems to be Solved by the Invention As mentioned above, in the conventional technology, when the copy paper should arrive at the position where the detection means is provided, this detection means is operated only once to detect the copy paper. I was deciding whether or not it was there. Therefore,
As shown by the solid line in Figure 2, even though the copy paper has arrived at the position where the detection means is provided, it may not be detected due to bending, even though there is no paper jam or paper jam. Regardless, a paper jam signal is output, and there is a risk of malfunction.

In particular, as shown in Japanese Utility Model Application Laid-open No. 59-66251'5+, in a copying machine that is not provided with a feed roller downstream of the fixing device, the copy paper tends to bend downstream of the fixing device, and the position If a copy paper detection means is provided in the printer, malfunctions are likely to occur.

B) Means for Solving the Problems The present invention provides a recording paper detecting means having an actuator that is provided so as to be movable forward and backward with respect to a recording paper feeding path;
means for operating the recording paper detection means a plurality of times when recording on a sheet of recording paper, and outputting a paper jam signal only when the recording paper is not detected for all the number of times of operation. This is a recording paper detection device for an electrostatic recording machine.

(E) Function Recording is performed on a single sheet of recording paper (at this time, the recording paper detection means is operated multiple times, and if the recording paper is detected even once, the recording paper has arrived at the analysis position If. In other words, it is determined that only a paper jam has occurred, so even if the recording paper is bent, it will not be detected incorrectly.

(f) Embodiment FIG. 1 is a block diagram showing the main parts of an electronic copying machine as an embodiment of the present invention. In this figure, ill is the main body of the copying machine, and (2) is the inside of the main body ol of the copying machine. The separation claw (6) and the cleaning device (7) are arranged in sequence 1. The inner bottom part iC of the copying machine main body +B is a paper feed cassette (9) in which copy paper (8) as recording paper is loaded and stored. However, it is removable from the right side and is colored blue.

A paper feed roller (10) is provided at the upper part near the downstream end of the #I paper feed cassette (9), and downstream of this paper feed roller (10), there is a paper feed roller that makes an upward U-turn. guide(
1 is provided. On the downstream side of the paper feed guide (11), there is a Kiku 1 sensor (1) that detects the arrival of copy paper (8).
A roller and its actuator (11 are provided, and downstream thereof, a pair of register rollers (110 and 111) are provided.
11t downstream of the separation claw (6)! In the IK, a pair of copy paper conveyance rollers αηHs and a liner guide (I9) are sequentially provided, and a pair of fixing rollers 1; 211 are provided on the downstream side of this paper feed guide θ→. There is. These row ninety-four systems are pressed against each other, and the upper part, that is, the copy paper (8
) is in contact with the toner on the roller (7).

:'I3 is a separation claw that separates the fixed copy paper (8) from the roller ca), force) is a second sensor that detects the arrival of the copy paper (8), and (251 is its actuator). be.

FIG. 3 is a block diagram showing the control circuit of this embodiment, in which (a) shows a microcomputer, @ke driver IC, and t28.
This is a dynamic display section consisting of 1H7 segment elements.

Next, the detection operation of the copy paper (8) will be explained based on the flowchart shown in FIG. 4, taking the second sensor (241) as an example. This shutter (16
1 is opened, that is, 2.2 seconds after the copy paper (8) starts moving, the first detection operation is performed. At that point, when the second sensor 1241 detects the presence of copy paper (8), flag 1 in the microcomputer 126i is set. In addition, the shutter (1b!
A second detection operation is performed 2.6 seconds after the second sensor (24I) is opened, and at that point, when the presence of the copy paper (8) is detected by the second sensor (24I),
Flag 2 in 61 is sected.

Then, looking at the state of flag 1 and flag 2, if neither flag is set, the copy paper (8) has not reached the position of the second sensor (241), so the copy paper (8) is not set. A signal is output to indicate a paper jam in the dynamic suction unit (layer).

In this example, each sheet of record paper is inspected twice.
Although the J operation is performed, this detection operation may be performed three or more times.

(g) Ta υ j When recording on a single sheet of recording paper, the recording paper detection means is operated in multiple attacks, and if the presence of recording paper is detected even once, the recording paper Since it is determined that the recording paper has reached a predetermined position, that is, it is determined that only a paper jam has occurred, there is no risk of a detection error even if the recording paper is not good.

On the other hand, even if the clog is low or there is no leakage, the 1-1 signal is output, and there is no risk of malfunction.

[Brief explanation of drawings]

The drawings all show one embodiment of the present invention, and Fig. 1 is a schematic configuration diagram of an electronic photocopier, Fig. 2 is a front view showing the second sensor, Fig. vJ3 is a block diagram, and Fig. 4 is a flowchart. It is. (8) Copy paper (recording paper), holder 1) Fixing roller, e.g. second sensor (recording paper detection means),
25!・・・actiniator,・lees・microcomputer.

Claims (4)

[Claims] (1) Recording paper detection means having an actuator that is provided to be movable forward and backward with respect to the recording paper feed path, and operating the recording paper detection means multiple times when recording on one sheet of recording paper. A recording paper detection device for an electrostatic recording machine, comprising means for outputting a paper jam signal only when recording paper is not detected for all the number of times the recording paper is detected. (2) A microcomputer is connected to the recording paper detection means, and when the recording paper detection means detects recording paper, a flag in the microcomputer is set, and when at least one flag is set, a paper jam occurs. A recording paper detection device for an electrostatic recording machine according to claim 1, wherein the recording paper detection device for an electrostatic recording machine is configured so that no signal is output. (3) The recording paper detection device for an electrostatic recording machine according to claim 1 or 2, wherein the recording paper detection means is provided downstream of the recording paper fixing device. (4) The recording paper detection device for an electrostatic recording machine according to claim 3, wherein a recording paper conveyance roller is not provided downstream of the recording paper detection means.