JPH0130738B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sheet feeding device for a copying machine or the like.

For example, in a semi-automatic document feeder, a manually fed document sheet is detected by a detection member, and based on the detection, a pair of paper feed rollers are operated to nip and feed the sheet onto the document table. .

This will be explained using drawings.

FIG. 1 is a cross-sectional view of the sheet feeding device, showing a state where it is placed on a copying machine 1. FIG. Guide plate 10 arranged at intervals above and below the manual paper feed slot
appears, allowing you to insert sheets.

Reference numeral 11 denotes a paper feeding member, which is composed of a rotating roller 11a having a fixed shaft, and a movable rotating roller 11b having a rotating shaft 23 supported on a fixed plate interlocked with a lever 22 having a shaft 21 as a rotating shaft. .

In the operating state, the movable rotating roller 11b rises to the position indicated by the two-dot chain line, comes into pressure contact with the rotating roller 11a, is rotated by a motor (not shown), and conveys the sheet inserted into the paper feed tray on the left side in the drawing. In the non-operating state, the movable rotating roller 11b is stopped at the position indicated by the solid line.

The stop lever 12 is rotatable about a shaft 24.
One end 12a of the lever 22 is engaged with a notch 25 of the lever 22.

When the sheet feeding member 11 is not operating, the opposite end of one end 12a of the stop lever 12 is located on the sheet path and has the function of preventing the sheet from advancing toward the left end (in the drawing). When the paper feeding member 11 is operated, the lever 22 is lifted upward about the shaft 21, so that the tip of the stop lever 12 is retracted from the sheet path (the position indicated by the two-dot chain line). 1
Reference numeral 3 denotes a sheet detecting member, which is a combination of a light source and a light receiving element, and detects the presence or absence of a sheet in the sheet path by reflected light.

Reference numeral 14 denotes a belt pulley that rotates an endless belt 15 that rotates around the surface of the glass plate 2 of the document table and conveys the sheet from the paper feed member 11 to the document placement section. It rotates clockwise in conjunction with the operation of member 11. These constitute a document feeder.

The operation and operation of this sheet feeding device will be explained. When the sheet is inserted between the guide plates 10, the movable rotating roller 11b is in a retracted position, so the stop lever 12 can be inserted until it abuts. Here, detection member 1
3 detects the leading edge of the sheet.

When the detection member 13 detects the leading edge of the sheet, it enters the operating state. That is, the shaft 21 rotates clockwise (in the direction of the arrow) by the operation of a paper feed solenoid (not shown), and the sheet is sandwiched between the rotary roller 11a and the movable rotary roll 11b. At the same time, the tip of the stop lever 12 retreats from the sheet path, and the sheet is conveyed to the left.

When the remaining end of the sheet passes the detection member 13, the motor continues to rotate, but the paper feed solenoid becomes inactive, the movable rotating roller 11b lowers, and at the same time the end of the stop lever 12 faces into the sheet path, and the next The machine is in a position waiting for sheet insertion.

In the sheet feeding device as described above, when an optical detection operation is used for the detection member 13, the paper feed solenoid does not operate even if a sheet is inserted, and the sheet is not pinched between the rotating rollers 11a and 11b. At times, paper feeding and transportation stopped. This is the stop lever 12 at the tip of the seat.
This seems to be due to the fact that if the sheet vibrates in the vicinity of , or if the sheet is too close to the detection member 13 when manually fed, the detection member 13 does not instantly detect the sheet.

The present invention has been made for the purpose of preventing the occurrence of the above-mentioned accidents.The present invention has been made for the purpose of preventing the occurrence of the above-mentioned accidents. After colliding with the locking member, the locking member is retracted from the sheet conveyance path in response to a detection signal from a detection member that is disposed near the locking member and detects the presence at the leading edge of the sheet, and a pair of sheet feeding devices When the sheet is conveyed and discharged by operating, the detection operation of the detection member is stopped for a predetermined period of time, and when the detection signal is not output after the elapse of the predetermined period of time, the rotary roller for conveying the sheet is rendered inactive. The present invention provides a sheet feeding device that does the following.

A detailed explanation will be given below with reference to the drawings. FIG. 2 is a flowchart based on the present invention, and FIG. 3 shows an example of an electric circuit using a microcomputer (CPU). Paper feed detection provided in the detection member 13
When a sheet is detected by S ₁ and S ₂ , a delay circuit (0.5 second timer) is started, and at the same time, the drive circuit for the rotating rollers 11a and 11b is turned on, and both rollers 11a and 11b are started. After a predetermined time has elapsed due to the operation of the timer, the paper feed solenoid circuit is turned on, and then the timer is activated and after the predetermined time (0.2 seconds) has elapsed, the detection of the sheet by the detection member 13 is confirmed and the rotating rollers 11a and 11b are activated. The joined and sandwiched sheets are conveyed. When the end of the sheet passes the detection member 13 and the sheet is no longer detected, the paper feed solenoid is turned off, the rotating roller 11b descends, the two rollers separate, and the rotating roller 11 stops. The system waits for the next sheet to be inserted. The delay circuit (timer) is operated by inputting a pulse signal from an oscillator to the RAM and counting it.

In the process described above, both rotating rollers 11a,
By setting a period of 0.2 seconds during which the detection member did not operate after 11b was crimped and rotated, malfunctions caused by erroneous recognition could be completely eliminated.

The setting of 0.2 seconds in this example was determined experimentally based on the time required for the vibration of the sheet to stabilize immediately after it was sandwiched between the rotating rollers 11a and 11b. The setting time is
It is not limited to 0.2 seconds.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a sheet feeding device, FIG. 2 is a flowchart according to the present invention, and FIG. 3 shows an example of an electric circuit according to the present invention. 11a...Rotating roller, 11b...Movable rotating roller, 12...Stop lever, 13...Detecting member.

Claims (1)

[Claims] 1. In a sheet feeding device that transports the sheet to a document table after locking the leading edge of the sheet with a locking member, after the leading edge of the sheet collides with the locking member, the sheet is placed near the locking member and the sheet is A detection signal from a detection member that detects the presence of the leading end of the locking member causes the locking member to retreat from the sheet conveyance path, and when operating the pair of sheet supply members to convey the sheet, the operation of the detection member is stopped for a predetermined period of time. 2. A sheet feeding device, characterized in that when the detection signal is not output after a predetermined period of time has elapsed, a rotating roller for transporting the sheet is brought into a non-operating state.