JPH09150992A - Checking method for paper delivering sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a checking method for a paper delivering sensor which can check the operation of the paper delivering sensor securely by the visual observation, in the checking method for the paper delivering sensor to check the operation of the paper feeding sensor provided on the conveying route of an image forming device. SOLUTION: A timer 3011 is provided to a CPU 301 to control to light an LED, when the existence of a cut sheet is detected by a paper delivering sensor, and when the condition is converted from the first condition of the condition detecting that the cut sheet is passing, to the second condition of the condition existing no cut sheet, the display of the LED is maintained as the prior display condition, and after a specific time set in the timer 3011 passes, the display of the LED is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of checking a paper passing sensor for confirming a normal operation of a paper passing sensor provided in an image forming apparatus.

[0002]

2. Description of the Related Art A sheet passing on a transfer path of a transfer sheet (hereinafter referred to as a "cut sheet") in an image forming apparatus, for example, a copying machine, for confirming the presence of a cut sheet for carrying control and jam detection. The sensor is installed. Normal operation of the paper passing sensor is essential for normal copying, and some copying machines are equipped with a paper passing sensor check mode to check whether the paper passing sensor operates normally. Many.

In the paper passing sensor check mode, the cut sheet is fed, conveyed and discharged as in the case of image formation, and when the presence of the cut sheet is detected by the paper passing sensor, L is set.
By turning on the ED or the like, it is confirmed whether the operation of the paper passing sensor is normal. In the paper passing sensor check mode in the conventional copying machine, the LED is turned on when the presence of the cut sheet is detected by the paper passing sensor, and is turned off immediately when it is no longer detected.

[0004]

However, since the conveyance speed is remarkably improved with the progress of the paper conveyance technique,
The conventional method has a problem in that the lighting time of the LED or the like is too short and it may not be possible to make an accurate visual confirmation.

For example, the conveyance speed of cut sheets in recent copying machines has reached 340 mm / sec, and when A4 size cut sheets (short side 210 mm) are used,
The detection time by the paper passing sensor is theoretically about 0.62 seconds. It is expected that the transport speed will be even faster in the future, and it was an urgent need to develop a method that can reliably check the paper passing sensor.

In view of the above problems, it is an object of the present invention to provide a method of checking a sheet passing sensor which can surely check the operation of the sheet passing sensor.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the invention of claim 1 is directed to a state in which a sheet passing sensor disposed on a transfer sheet conveying path of an image forming apparatus detects a state during passage of a transfer sheet. From the first state to the second state in which the transfer sheet is absent, and when the second state to the first state, the display of the display unit is changed, In a method of checking a sheet passing sensor for checking an operating state, when the sheet passing sensor changes from a first state to a second state, the display on the display unit is kept in the previous display state for a predetermined time. Will change later.

[0008]

1 is a schematic diagram showing a copying machine provided with a paper passing sensor check mode as an application example of the present invention. The broken line in the figure indicates the cut sheet conveyance path. From upstream to downstream of this transport route,
Paper feed cassette 101, conveyance roller 102, timing roller 103, photosensitive drum 104, conveyance belt 105,
A fixing device 106, a paper discharge roller 107, and a paper discharge tray 108 are provided. Then, a first paper passing sensor 109 near the paper feed cassette 101, a second paper passing sensor 110 before the timing roller 103, and a third paper passing sensor between the fixing device 106 and the paper discharging roller 107. 111 are provided respectively.

The paper feed cassette 101 has cut sheets stacked therein and accommodated therein, and the front end side thereof is detachably inserted from the outside of the copying machine casing to the inside. A paper feed roller (not shown) is provided at the insertion position of the paper feed cassette 101, and is configured to feed one by one from the uppermost cut sheet in the paper feed cassette 101.

Conveying roller 102, timing roller 10
3, transport belt 105, fixing device 106, paper discharge roller 10
Each of 7 is connected to a drive mechanism (not shown) and is configured to be driven at an appropriate timing. Although not shown around the photoconductor drum 104, a charger,
An exposure unit, a developing device, a transfer charger, a static eliminator, etc. are arranged, and the electrostatic copy process is executed by operating the print start switch 201, and the toner image is transferred and fixed on the cut sheet conveyed along the conveyance path. A fixed copy image is obtained through the container 106.

The sheet passing sensors 109 to 111 detect the presence of a cut sheet at each position and determine whether or not the cut sheet exists at that position by the control unit (CP) of the copying machine.
Instruct U301). The result of detection by the sheet passing sensors 109 to 111 is used for conveyance control of a cut sheet and detection of a jam. More specifically, the detection result of the first sheet passing sensor 109 is used to confirm whether or not the cut sheet is fed from the sheet feeding cassette 101 and to detect a jam at that position.

The result of the detection by the second sheet passing sensor 110 is that the cut sheet is conveyed in synchronization with the rotation of the photosensitive drum 104 on which the toner image is held, and the position of the second sheet passing sensor 110. It is used for jam detection in. The detection result of the third sheet passing sensor 111 is used for checking whether the cut sheet has been ejected and for detecting a jam at the position of the third sheet passing sensor 111.

The purpose, function and the like of the paper passing sensor are not limited to those in this embodiment.

An operation panel as shown in FIG. 2 is arranged on the upper part of the casing of the copying machine. In addition to the print start switch 201, the numeric keypad 202, and the display 203, the operation panel is provided with a paper passing sensor check mode instruction switch 204 and LEDs 205, 206, 207. FIG. 3 is a control block diagram of the copying machine according to the present embodiment. The CPU 301 instructs each unit of the copying machine to perform an operation and a display according to the input in response to an input from each switch on the operation panel. To do. LEDs 205, 206,
207 is turned on / off by the CPU 301 in response to detection signals from the sheet passing sensors 109, 110, 111 in the sheet passing sensor check mode described later.
The CPU 301 has a timer 30 for controlling the display.
11 is built in.

Returning to FIG. 2, the paper passing sensor check mode instruction switch 204 is operated to check the operation of the paper passing sensor. By pressing this switch 204, the paper passing sensor check mode is set. The cut sheet is fed, conveyed, and discharged in the same manner as when the image is formed, and the operating state of each sheet passing sensor in the meantime is indicated by the LED 20.
Displayed at 5-207. The paper passing sensor check mode ends when the cut sheet is discharged. Note that when the cut sheet is conveyed in the paper passing sensor check mode, an image forming process such as formation and development of a latent image on the photosensitive drum 104, and transfer and fixing of a toner image on the cut sheet is not performed.

4 to 7 are flowcharts showing the display control processing by the CPU 301. Hereinafter, the display control process will be described with reference to these drawings. FIG.
3 is a flowchart showing the processing contents of the CPU 301. If the operator presses the paper passing sensor check mode instruction switch 204, the pressing of the switch 204 is detected in the step (S41) of the key input process, and it is confirmed that the paper passing sensor check mode is set. After (S
42), in steps S44, S45 and S46, display control processing for the LEDs 205, 206 and 207 is executed.

When it is detected in the key input processing that any switch other than the sheet passing sensor check mode instruction switch 204 is pressed, other display control processing (S43) such as data display on the display 203 is performed. FIG. 5 is a subroutine showing the contents of the display control processing of the LED 205 performed in step S44.

First, it is detected whether or not the LED 205 is on (lighted) (S441), and if the LED is off (light off), the LED 205 is detected when the sheet passing sensor detects the presence of the cut sheet. A display start process is performed to change the display of to ON (S442). On the other hand, the LED 20
If 5 is turned on, the display end process is performed to turn off the LED 205 when the sheet passing sensor does not detect the presence of the cut sheet (S443).

In the display start process, as shown in the flowchart of FIG.
If the state is not an on-edge (the state of the sensor has changed from OFF to ON), this processing is ended. When the on-edge of the paper passing sensor 109 is detected in S4421, the display of the LED 205 is turned on in S4422.

That is, when the paper passing sensor changes from OFF (a state in which the presence of a cut sheet is not detected) to ON (a state in which the presence of a cut sheet is detected), the LED is immediately turned on.

In the display end process, as shown in the flow chart of FIG.
When the off edge (the state of the sensor changes from on to off) is detected, the timer 30
11 is set (S4432). If the sheet passing sensor 109 is not off-edge, the state of the sheet passing sensor 109 is checked, and if it is not off, the process is ended as it is (S4).
433). If the paper passing sensor 109 is off, the timer 3
Check whether 011 has ended, and
Wait until 11 is completed (S4434, S443
5), the display of the LED 205 is changed to off (S443).
6).

That is, when the paper passing sensor changes from on (a state in which the presence of a cut sheet is detected) to off (a state in which the presence of a cut sheet is not detected), a predetermined time LE
Hold D on and then off. It is preferable that the set time of the timer 3011 is about 1 to 1.5 seconds.
It is not limited to this.

Returning to the flowchart of FIG. 4, S45,
In S46, display control processing for the LEDs 206 and 207 is performed. The processing contents of S45 and S46 are S
The explanation is omitted because it is the same as 44. After that, S47
Then, after the completion of the paper passing sensor check mode, the processing is ended.

By performing the above processing, the LED lighting time is the time set by the timer even if the cut sheet conveying speed is increased, so that the operation of the paper passing sensor can be surely confirmed visually. Can be done.

The number and positions of the sheet passing sensors are not limited to the numbers and positions of the sheet passing sensors in this embodiment, and the number and position of the sheet sensors may be increased or decreased. Further, in the present embodiment, the LED is used as the display means for checking the paper passing sensor, but a liquid crystal display or the like can be used as an alternative display means.

[0026]

According to the first aspect of the invention, there is an effect that the operation of the sheet passing sensor can be surely checked even when the cut sheet is conveyed at a high speed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a cut sheet conveyance path in a copying machine as an application example of the present invention.

FIG. 2 is a diagram showing an example of the shape of an operation panel arranged in a copying machine as an application example of the present invention.

FIG. 3 is a control block diagram of a copying machine as an application example of the present invention.

FIG. 4 is a flowchart showing the processing contents of a CPU 301.

FIG. 5 is a flowchart showing the contents of LED display control processing performed by a CPU 301.

FIG. 6 is a flowchart showing the contents of display start processing performed by the CPU 301.

FIG. 7 is a flowchart showing the contents of display end processing performed by the CPU 301.

[Explanation of symbols]

 101 Paper Feed Cassette 102 Conveyor Roller 103 Timing Roller 104 Photosensitive Drum 105 Conveyor Belt 106 Fixer 107 Paper Ejection Roller 108 Paper Ejection Tray 109, 110, 111 Paper Pass Sensor 201 Print Start Switch 202 Numeric Keypad 203 Display 204 Paper Pass Sensor Check Mode Instruction switch 205, 206, 207 LED 301 CPU 3011 timer

Claims (1)

[Claims] 1. A sheet passing sensor disposed on a transfer sheet conveying path of an image forming apparatus changes from a first state, which is a detection state during transfer sheet passing, to a second state, in which there is no transfer sheet. In the method of checking the paper passing sensor, in which the display of the display unit is changed and the operating state of the paper passing sensor is checked when the paper passing sensor changes from the second state to the first state, A method for checking a paper passing sensor, characterized in that, when the first state is changed to the second state, the display on the display unit is kept in the previous display state and is changed after a predetermined time.