JPS61174538A - Automatic original feeding device - Google Patents

Abstract

PURPOSE:To set an original initially at an invariably correct position by measuring the time from the supply of a reversing signal to a motor to the actual reversing of the motor and using it as a positioning correcting signal in original backward feeding operation. CONSTITUTION:Only one of originals 6 stacked in a paper feed tray 5 is sent out onto an original platen 8 by a paper feed roller 7 and a motor driving circuit 16 rotates an ADF motor 14 at this time as shown by an arrow. Consequently, an original from is clamped between a belt 13 and the original platen 8 and moved as shown by an arrow. Then, the motor driving circuit 16 supplies the ADF motor 14 with a signal for reversing at time t1, but the motor 14 which rotates forward so far continues to rotate forward awhile. The motor 14 stops at time t2. Then, the motor 14 begins to reverse and the number of pulses detected by an encoder 15 increases; and a roller 11 is turned reverse through the reversing of the motor 14 to move the original 17 backward; and the motor driving circuit 16 sends a stop signal to the motor 14 at time t3 to stop the motor 14 after moving the original 17 by a specific quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic document feeder used in electronic copying machines and the like.

(Prior Art) An electronic copying machine exposes a charged drum to light in accordance with document information, and then forms a toner visible image on a static II image formed on the drum surface. This is a device that transfers images onto recording paper. In recent years, this type of electronic copying facility has been widely used for information copying in all fields of industry. Recent electronic copying machines are available on the market that not only automatically make one copy, but also have a zoom function for enlarging or reducing images. Furthermore, electronic copying machines have also appeared that are equipped with an automatic document feeder that can sequentially feed a plurality of documents onto a document table and copy them.

FIG. 3 is a diagram showing a conventional example of an automatic document feeder.

In the figure, 1 is the main body of the electronic copying machine, 2.3 is a paper feed cassette loaded with copy paper corresponding to the size of the copy paper (for example, A4.85, etc.), and 4 is a paper ejector for receiving copied copy paper. It's a plate. 5 is a paper plate on which a plurality of originals 6 are placed; 7 is a paper feed roller that feeds the originals one by one to the original platen 8; and 9 is a document cover.

The originals 6 placed on the paper feed fln5 are sent out one by one by a paper feed roller 7 rotated by a drive source (not shown), and are transported in the direction of the arrow by a transport mechanism (not shown). , positioning is performed by stopping at a stopper point S.

(Problem to be solved by the invention) In the case of a conventional document feeder of this type, the drive source (motor)
The copy paper could not be stopped correctly at the stop point S due to the inertia of the copy paper, the difference in the paper used as the original, or the remoteness of the operating environment in which the electronic copying machine is installed.

The present invention has been made in view of these points, and
The purpose is to realize an automatic document feeder that can always accurately position document sheets on a document table.

(Means for Solving the Problems) The present invention, which solves the above-described problems, is configured such that a motor sequentially feeds the document onto the document table and then reversely feeds it by a predetermined amount to position the document. This automatic document feeder is characterized in that the time from when a reverse rotation signal is given to the motor until the motor actually reverses is measured and used as a positioning correction signal when the document is reversely fed. be.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of the present invention. The apparatus shown in the figure is a so-called swing-back type automatic document feeder in which a motor sequentially feeds a document onto a document table and then reverses it by a predetermined amount to position the document. Components that are the same as those in FIG. 3 are designated by the same numbers. The liner plate 5 is provided on the opposite side from the conventional example shown in FIG. In the figure, reference numerals 11 and 12 denote rollers around which a belt 13 is wound, and the roller 11 is driven by an automatic document feed motor (hereinafter referred to as an ADF motor) 14. 15 is an encoder for detecting the rotation speed and rotation direction of the ADF motor 14;
6 is the detection clock of the encoder 15 and the ADF motor 1
This is a motor drive circuit that receives a reference clock for driving the ADF motor 14 and drives the ADF motor 14.

Power may be transmitted from the ADF motor 14 to the roller 11 by using a belt as shown in the figure, or by using a gear mechanism. The encoder 15 includes, for example, a gear directly connected to the rotating shaft of the ADF motor 14, and a photosensor that allows light to pass intermittently through the teeth of the gear.

As the motor drive circuit 16, for example, a microcomputer is used because it is necessary to perform arithmetic processing. The operation of the device configured as described above will be explained in detail with reference to the timing chart shown in FIG.

In FIG. 2, (a) is the ADF by the encoder 15.
Rotation detection signal of motor 14, (b) 〇F motor 14
FIG.

Only one sheet of the original N6 placed on the paper feed lIr15 is sent onto the document table 8 by the paper feed roller 7. At this time, the motor drive circuit 16 drives the ADF motor 14 to rotate in the direction of the arrow. As a result, the original paper 17 sent onto the original table is pressed between the belt 13 and the original table 8, and as the belt 13 moves in the direction of the arrow, it also moves in the same direction. Here, the direction indicated by the arrow in the figure is defined as the forward direction.

Next, the motor drive circuit 16 detects time j! (See (b) in Figure 2), send the signal to rotate in the opposite direction to F motor 1.
Give to 4. However, the ADF motor 14, which had been rotating in the forward direction until then, cannot instantly reverse rotation due to inertia, and continues to rotate in the forward direction for a while. However, the rotational speed becomes slow as shown in FIG. 2(a). Then, at time t2, the rotation of the ADF motor 14 stops. ADF motor 14 at time t1
The period T from when a reversal signal is applied to the motor until the motor stops at time t2 is a so-called braking period. During this braking period, the original N17 also moves in the forward direction. The movement age during this brake period T needs to be corrected when the original is moved in the opposite direction.

At time t2, after being temporarily stopped, ADF motor 1
4 now starts rotating in the opposite direction. At the same time, the pulses detected by the encoder 15 increase as shown in FIG. 2(a). Then, when the F motor 14 rotates in the reverse direction, the roller 11 also rotates in the reverse direction, and the document 17 is pressed against the belt 13 and moves in the opposite direction. Then, when the motor drive circuit 16 moves the document 17 by a predetermined distance, the ADF
A stop signal is sent to the motor 14 at time t3 to stop the motor.

By the way, since the motor drive circuit 16 is supplied with the output of the encoder 15 and the 1 & quasi-clock, the motor drive circuit 16 detects whether the ADF motor 14 is in The time T until the stop at time t2 can be determined. Since it can be known that the ADF motor 14 has stopped because the output of the encoder 15 has stopped changing, the time difference can be determined by counting the number of reference clocks from tl to tl. Once the time T is determined, the motor drive circuit 16 can calculate the distance that the document 17 has moved in the forward direction within the time T (brake period T described above).

The distance that the original 17 moved in the forward direction during the braking period is ΔX
Then, by adding ΔX when moving in the opposite direction, the distance traveled by the document within the braking period can be corrected. Therefore, the motor drive circuit 16 actually
From the time t2 when the F motor 14 starts to rotate in reverse, the time corresponding to the correction distance is added to the time when a stop signal is given to the ADF motor 14, and the time t when an actual motor stop signal is given.
I'll decide on 3. By performing such control, the positioning of the swingback type document feeding device used in the present invention can be performed with extremely high accuracy. That is, manuscript 1
7 can always be brought to the stop point S. As a result, it is possible to obtain a copy image without shifting the image position.

(Effects of the Invention) As described above in detail, according to the present invention, the distance that the document moves in the forward direction from when a reverse rotation signal is given to the ADF motor until the ADF motor stops is corrected when moving in the reverse direction. As a result, the original can always be initially set in the correct position, which has a great practical effect.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a timing chart showing the operation of each part, and FIG. 3 is a diagram showing an example of the configuration of a conventional device. 1... Electronic copying machine body 2.3... Paper feed cassette 4... Paper ejection rm 5... Paper plate 6.1
7... Original 7... Paper feed roller 8... Original table 9... Original cover 11.12... Roller 13... Belt 14... ADF motor
15... Encoder 16... Motor drive circuit patent applicant Roku Konishi Photo Industry Co., Ltd. Agent Patent attorney Fuji Ijima Jigai 1 person

Claims (1)

[Claims] In an automatic document feeder that is configured to use a motor to sequentially feed a document onto the document table and then move it backwards by a predetermined amount to position the document, a reverse signal is given to the motor, and then the motor actually reverses. What is claimed is: 1. An automatic document feeder, characterized in that the time until the original is reversely fed is measured and used as a positioning correction signal when the document is reversely fed.