JPH05132191A - Paper feed device - Google Patents

Abstract

PURPOSE:To enable the occurrence of a paper feed error to be prevented by measuring a time from the driving of a feed roller to the arrival of a recording paper sheet to the predetermined position, and making a comparison between the measured time and a reference time for making judgement as to whether there is any drop in paper feed force. CONSTITUTION:When a feed roller 2 is caused to rotate in a copying machine, CPU starts to process an elapsed sheet feed time. The CPU ends the elapsed time processing, upon receipt of a paper sheet detection signal from a recording paper sheet detector, and makes judgement as to whether the elapsed paper sheet feed time is longer than a reference value for judging a drop in a paper sheet force. When the time is found longer than the reference value, the CPU judges that sheet dust or the like adhering to the feed roller 2 causes a drop in the paper sheet feed force thereof, and makes a display device show to that effect. At the same time, a solenoid 17 and the roller 2 are driven for the predetermined time. As a result, the sheet dust or the like adhering to the roller 2 is stuck to and removed with an adhesive cleaning tape 14, and the paper sheet feed force of the roller 2 is thereby restored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device in an image forming apparatus such as a PPC, PPF, laser printer or the like.

[0002]

2. Description of the Related Art In a sheet feeding device of an image forming apparatus such as a PPC, a PPF, and a laser printer, when the amount of paper dust adhered to the sheet feeding roller increases, the frictional force between the sheet feeding roller and the recording sheet increases. The paper feeding power is reduced, and the paper feeding power is lowered to cause a paper feeding failure.

[0003]

Conventionally, there has not been provided a device for detecting that the paper feeding force of the paper feeding roller has decreased. For this reason, even if the paper feeding power of the paper feeding roller is reduced, it is not possible to detect that early,
There was a problem that a paper feed failure occurred.

It is an object of the present invention to provide a sheet feeding device capable of detecting that the sheet feeding force of a sheet feeding roller is lowered and preventing occurrence of sheet feeding failure.

[0005]

According to the present invention, there is provided a sheet feeding device for measuring the time from when the sheet feeding roller is driven until the recording sheet fed by the sheet feeding roller reaches a predetermined position. And comparing the measurement time measured by the time measuring means with a predetermined reference value, and determining that the paper feeding force by the paper feeding roller is reduced when the measurement time is longer than the reference value. And means are provided.

It is preferable to provide an informing means for informing that when the determining means determines that the sheet feeding force of the sheet feeding roller is reduced. Further, it is preferable to provide a cleaning unit that automatically cleans the sheet feeding roller when the determining unit determines that the sheet feeding force of the sheet feeding roller is reduced.

[0007]

The time from when the paper feed roller is driven until the recording paper fed by the paper feed roller reaches the predetermined position is measured. Then, the measured time is compared with a predetermined reference value, and when the measured time is longer than the reference value, it is determined that the paper feeding force of the paper feeding roller is reduced. When it is determined that the sheet feeding force of the sheet feeding roller is reduced, the user is informed of that fact by an informing unit such as a display device. When it is determined that the sheet feeding force of the sheet feeding roller is reduced, the sheet feeding roller is cleaned by the cleaning unit, for example.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a sheet feeding device of a copying machine will be described below with reference to the drawings.

FIG. 1 and FIG. 2 show a paper feeding section of a copying machine.

A paper feed cassette 1 is mounted on the main body of the copying machine. In the paper feed cassette 1, a plurality of recording papers P are stacked and stacked. Paper cassette 1
The recording papers P stocked at 1 are fed one by one by the paper feed roller 2 provided in the main body of the copying machine being rotationally driven in the clockwise direction, conveyed to a registration roller not shown, and temporarily stopped. To do. Then, by rotating the registration roller at a predetermined timing, the recording paper P is sent to a photosensitive drum (not shown).

A recording paper detector 3 (see FIG. 2) is arranged in the recording paper conveyance path from the paper feed cassette 1 to the registration rollers and in front of the registration rollers. As the recording paper detector 4, for example, a photoelectric detector is used.

A cleaning device 10 for removing paper dust and the like adhering to the paper feed roller 2 is arranged above the paper feed roller 2. The cleaning device 10 includes an oscillating plate 11 having an elongated rectangular shape.
A cleaning tape core 12 rotatably and detachably attached to one end of the oscillating plate 11, and a winding core 13 rotatably and detachably attached to the other end of the oscillating plate 11. Is equipped with. A cleaning tape 14 having adhesiveness on one surface is wound around the cleaning tape core 12 with the adhesive surface facing outward. The outer end of the cleaning tape is fixed to the winding core 13.

A cleaning tape core 12 on the rocking plate 11
The end on the side of is attached to the main body of the copying machine via a horizontal pin 15. Therefore, the swing plate 1
1 is supported by the main body of the copying machine so as to be swingable about a pin 15 so that the winding core 13 can move toward and away from the paper feed roller 2.

The lower end of a coil spring 16 whose upper end is fixed to the main body of the copying machine is fixed to the end of the oscillating plate 11 on the side where the winding core 13 is attached. There is. From this spring 16, the swing plate 11
The end of the winding core 13 on the side to which the winding core 13 is attached is always urged upward. The tip of the actuator 17a of the solenoid 17 mounted downward on the copying machine body hits the upper surface of the middle of the length of the rocking plate 11, whereby the rocking plate 11 stands still. The actuator 17a of the solenoid 17 is normally located in the retracted position as shown in FIG. It is held in an angular position.

When the solenoid 17 is driven, the actuator 17a advances to swing the rocking plate 11 clockwise as shown in FIG. 2, and the cleaning tape 14 wound on the winding core 13 is fed. It is pressed against the paper roller 2.
When the paper feeding roller 2 is rotationally driven in the clockwise direction in this state, the cleaning tape 14 is wound around the winding core 13 by the friction between the paper feeding roller 2 and the cleaning tape 14. In addition, the paper feed roller 2 is attached to the adhesive surface of the outer surface of the cleaning tape 14.
The paper dust and the like adhering to the paper is absorbed and the paper dust and the like adhering to the paper feed roller 2 is removed.

FIG. 3 shows the electrical construction of the copying machine.

The copying machine is controlled by the CPU 20.
The CPU 20 is a ROM 21 that stores the program and the like.
And a RAM 22 for storing necessary data. The ROM 21 stores the reference value for determining the lowering of the sheet feeding force. The CPU 20 has a detection signal from the recording paper detector 3 for detecting that the recording paper has been conveyed to a predetermined position before the registration position, an input signal from the operation unit 31 provided with various operation keys, and the like. Is entered. CPU
From 20, a control signal is sent to the drive device 32 of the paper feed roller 2, the solenoid 17 for moving the cleaning device 10 of the paper feed roller 2 to the operating position, the display device 33, and the like.

FIG. 4 shows the procedure of the processing for determining the lowering of the sheet feeding force by the CPU 10.

This process is performed every time the paper feed roller 2 is rotationally driven. When the paper feed roller 2 is driven to rotate,
The paper feeding time counting process is started (step 1). When the recording paper detection signal from the recording paper detector 3 is input (step 2), the counting of the feeding time is ended, and whether or not the counted feeding time is longer than the reference value for feeding power reduction judgment Is determined (step 3). The reference value for determining the lowering of paper feeding ability is
If the paper dust or the like adheres to the paper feed roller 2 and the paper feed force of the paper feed roller 2 is lowered, the paper feed force of the paper feed roller 2 is not lowered enough to cause a paper feed failure. It is set to a value that can be detected. The reference value for determining the lowering of paper feeding ability is
It is determined by experiments.

When the counted paper feed time is longer than the reference value for the paper feed power reduction determination, it is determined that the paper feed roller 2 is reduced in paper feed power due to the adherence of paper dust or the like to the paper feed roller 2. The fact that the sheet feeding force of the sheet feeding roller 2 has decreased is displayed on the display device 33 (step 4), and the solenoid 17 and the sheet feeding roller 2 are driven for a predetermined time (step 5). As a result, the paper dust or the like attached to the paper feed roller 2 is removed by the cleaning tape 14. Then, this processing of this time ends. When the counted paper feed time is equal to or less than the reference value for paper feed force reduction determination in step 3, the processing of this time is ended without performing the processing of steps 4 and 5.

According to the above-described embodiment, it can be detected that the sheet feeding force of the sheet feeding roller 2 has decreased. Further, when it is detected that the paper feeding force of the paper feeding roller 2 is lowered, the fact can be notified to the user and the paper feeding roller 2 can be automatically cleaned. Occurrence can be prevented in advance.

Although the cleaning device 10 for cleaning the paper feed roller 2 is provided in the above embodiment, such a cleaning device may not be provided. If the cleaning device is not provided, the user or the like may clean the paper feeding roller 2 when the display device 33 displays that the paper feeding force of the paper feeding roller 2 is low.

Cleaning device 1 for cleaning the feed roller 2
When 0 is provided, it is not necessary to display that the paper feeding force of the paper feeding roller 2 is low when the timed paper feeding time is longer than the reference value.

The cleaning tape core 11 and the take-up core 12 are reversed in position, and a drive mechanism for rotating the take-up core 12 is provided. The take-up core 12 may be rotationally driven in the clockwise direction so that the take-up core 12 and the paper feed roller 2 move in mutually opposite directions.

[0024]

According to the present invention, it is an object of the present invention to provide a sheet feeding device capable of detecting a reduction in sheet feeding force of a sheet feeding roller and preventing occurrence of sheet feeding failure.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating a paper feeding unit of a copying machine.

FIG. 2 is a schematic configuration diagram of a sheet feeding unit showing a state in which a cleaning device is located at an operating position.

FIG. 3 is an electrical block diagram showing an electrical configuration of the copying machine.

FIG. 4 is a flowchart showing a procedure of a processing for determining a decrease in sheet feeding power by the CPU 20.

[Explanation of symbols]

 2 paper feed roller 3 recording paper detector 10 cleaning device 17 solenoid 20 CPU 21 ROM 22 RAM 32 display device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Nishino 1-2-2 Tamatsukuri, Chuo-ku, Osaka-shi, Osaka Mita Industry Co., Ltd.

Claims (4)

[Claims] 1. A time measuring means for measuring a time from when the paper feeding roller is driven to when a recording paper fed by the paper feeding roller reaches a predetermined position, and a measuring time measured by the time measuring means. A paper feeding device comprising: a predetermined reference value; and a determination unit that determines that the paper feeding force of the paper feeding roller is reduced when the measurement time is longer than the reference value. 2. When the determination unit determines that the sheet feeding force of the sheet feeding roller is reduced, an informing unit is provided for informing that fact. Paper feeder. 3. A cleaning unit is provided which automatically cleans the sheet feeding roller when the determining unit determines that the sheet feeding force of the sheet feeding roller is reduced. The sheet feeding device according to claim 1. 4. An informing unit for informing that the sheet feeding force by the sheet feeding roller is lowered by the determining unit, and a sheet feeding force by the sheet feeding roller by the determining unit. 2. The sheet feeding device according to claim 1, further comprising: a cleaning unit that automatically cleans the sheet feeding roller when it is determined that the sheet feeding roller is lowered.