JPS61192651A - Automatic original transfer device - Google Patents

Abstract

PURPOSE:To enable the position of an original which is being transferred, to be corrected to a given position by detecting whether or not the original is being transferred along the reference line in respect to the lateral direction based on the output power of each of two light quantity detectors which are arranged on the both sides of the transfer path. CONSTITUTION:When an original passes underneath the array 6 of photodiodes, light from the array 6 is shaded preventing it from being sensed by light quantity detectors 7 and 8. And when the original 2 is transferred while it is shifted to the left side, the light to be sensed by the detector 7 is shaded to a greater extent. Accordingly, the output from the detector 8 is greater than that from the detector 7, and the difference between these two outputs is inputted into a microcomputer 10 by a comparator 13 as a signal in relation to the current position of the original. Therefore, this allows the computer 10 to judge the condition that the original 2 is being transferred while it is shifted to the left side. Next, if the inputted signal allows the computer 10 to judge the condition that the original 2 is being transferred while it is offset from the reference line, the computer allows a solenoid 41 to be ON permitting an original position correction roller 4 to be activated. And the correction roller continues correcting the position of the original until the signal indicating that the original is in the reference position, is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an automatic document feeder for a copying machine that automatically corrects the conveyance position of a document set on a document tray, hereinafter referred to as ADF. ) regarding.

<Prior Art and Its Disadvantages> The ADF of a copying machine transports originals set on an original tray one by one onto an original table and copies them automatically. When using this ADF when copying a large number of sheets of the same size originals, the user only has to set the originals on the original tray, and the ADF eliminates the troublesome task of placing the originals on the copying machine's original stand. It is very convenient because it can be done easily.

However, with conventional ADFs, if the size of the original is different or the position of the original is shifted when setting the original on the tray, the original will not be placed correctly at the copying position on the original table and will not be placed correctly on the copy paper. Sometimes the original image was not copied.

The present applicant has already proposed an ADF that improves this drawback and automatically corrects the position when the conveyance position is detected during conveyance of the document to the document table (Japanese Patent Application No. 59 However, in the ADF according to this application, the conveyance position detection and conveyance position correction are limited to correction along one side edge of the conveyance path, and correction to an arbitrary position cannot be performed. This is because optical sensors that turn on and off depending on the presence or absence of light are installed at several predetermined locations as a means of detecting the document position. As shown in the figure, a large number of optical sensors (81 to Sn) had to be arranged in a row to cross the document transport path.

<Object of the Invention> In view of the above drawbacks, it is an object of the present invention to provide an automatic document feeder that can correct the document conveyance position to an arbitrary position with a simple configuration.

<Structure and Effects of the Invention> The present invention includes a document position detection means that detects the conveyance position of the document on the document conveyance path, a document leading edge detection sensor that detects the leading edge of the document, and a document leading edge detection sensor that detects the leading edge of the document. a timer that starts when the document is detected and times up when the document is conveyed a predetermined length shorter than the length of the document, and a light emitting element array installed perpendicularly to the document conveyance path at a position close to the document leading edge detection sensor; two light intensity detectors that operate when the timer times up and are installed at positions facing the light emitting element array across the document transport path, and each of the two light intensity detectors The present invention is characterized in that it is detected based on the detection output whether or not the document is being conveyed to a reference position in a direction perpendicular to the document conveyance direction.

With the above configuration, according to the present invention, the following effects can be achieved.

Set the transport position to 2 while transporting the original to the copying position on the document table.
Detection is possible based on the difference in the amount of light that enters the two light intensity detectors, so if you want to transport the document in the center of the document transport path, the detection outputs of the two light intensity detectors will be the same. You only need to correct the conveyance position as shown in the figure below.Also, if you want to convey the document closer to either the left or right side of the conveyance path,
The conveying position of the original may be corrected so that the detection output of the light amount detector on the side where the original is moved is no longer generated by a predetermined amount.

With this, it is possible to correct the document to any position by simply installing two sensors that detect the position of the document, and the AD
In addition to improving the usability of F, the cost can be kept lower than when using a conventional optical sensor array.

<Embodiment> FIGS. 1 and 2 are a front view and a plan view schematically showing an automatic document feeder according to an embodiment of the present invention.A document is placed on the document table 5o of the main body of the copying machine. A conveyor heald 5 for conveying is installed on the conveyor belt 50, and a document tray 1 is installed on the left side of the conveyor belt 5. The document tray 1 is inclined toward the document table 50 in order to facilitate conveyance of the documents 2 stacked thereon. Original guides la and lb are bent at the left and right ends of the original tray 1, and when setting an original on the original tray 1, it is set between the original guides la and lb. A conveyance roller 3 is installed at the right end of the document tray l. This conveying roller 3 is moved up and down by a solenoid 31, and when the solenoid 31 is turned on and moving downward, it comes into pressure contact with one of the upper ends of the stacked originals 2, and the motor 30 (see FIG. 3) The upper end of the original 2 is rotated by the drive of the original 2 and conveyed toward the original table.

When the solenoid 31 is turned off, the roller 3 moves upward and separates from the original. The conveyance roller 3 transports the original onto the original platen 50.
The document is conveyed to the conveyor belt 5 installed above, but between the feed roller 3 and the conveyor belt 5, the document is placed from the conveyor roller 3 side to the document position correction roller 4, the light emitting element array 6, and the light intensity detector 7.8. A tip detection sensor 9 is installed. The document position correction roller 4 is installed to rotate perpendicularly to the direction in which the document is conveyed, is driven by a drive motor 40 (see FIG. 3), and is moved up and down by turning a solenoid 41 on and off. When the solenoid 41 is on and moving downward, it comes into pressure contact with the document being conveyed and moves it perpendicular to the conveyance direction, and when the solenoid 41 is off and moving upward, it is separated from the document. There is. Light emitting element array 6
is a row of LEDs installed perpendicularly to the document conveyance direction close to above the document conveyance path that conveys the document from the document tray 1 to the document table 50. Light amount detectors 7.8 are installed at positions facing both ends of the light emitting element array 6 below the document transport path. Conveyor belt 5 in the center of the document conveyance path
A document leading edge detection sensor 9 is installed immediately in front of the document. The document leading edge detection sensor 9 is a transmission type optical sensor, and is turned on when the passage of the document is detected.

FIG. 3 is a block diagram of the control section of the above embodiment. The microcomputer 10 includes a ROM 11 that stores control programs, etc., and a RAM 1 that temporarily stores input data, etc.
2. Driver 15 that drives and controls the motor and solenoid;
A comparator 13, a document leading edge detection sensor 9, and a timer 14 are connected to the comparator 13, light amount detectors 7 and 8 are connected to the driver 15, and motors 30 and 40 and solenoids 31 and 41 are connected to the driver 15, respectively. The motor 30 drives the conveyance roller 3, and the motor 40 drives the document position correction roller 4.

Conveyance roller 3. When the document position correction roller 4 is driven, the solenoids 31 . The solenoid 41 is turned on to press the roller against the document.

These operations are performed under the control of the microcomputer 10. The timer 14 is a timer that starts when the leading edge of the document that has started to be conveyed from the document tray 1 onto the document conveyance path is detected by the document leading edge detection sensor 9, and times out when the leading edge of the document reaches a position immediately in front of the conveyor belt 5. It is a timer that has time. The comparator 13 compares detection outputs based on the light amount of the light emitting element array 6 received by the light amount detector 7.8, and inputs the result to the microcomputer 10.

FIG. 4 shows a schematic side view of the above embodiment from the direction of arrow A in FIG. The light intensity detectors 7 and 8 are both light emitting element arrays 6
It is installed in a symmetrical position so that it can receive light exactly in the longitudinal direction. Therefore, when the document 2 is not present on the document conveyance path (the light from the light emitting element array 6 is detected by the light amount detector 7.
When the light incident on the detector 8 is not blocked, the light amount detectors 7 and 8 receive the same amount of light and output the same detection output to the comparator 13. The original 2 is conveyed from the front side to the back side of the figure. When the document 2 passes under the light emitting element array 6, the light from the light emitting element array 6 is transmitted to the light amount detector 7.
．． Blocks light from entering 8. When the original 2 is being conveyed to the left (towards the original guide la side), the detection output of the light intensity detector 8 is larger than that of the light intensity detector 7 in order to block more light entering the light intensity detector 7. Since the comparator 13 inputs the difference as an original position signal to the microcomputer 10, the microcomputer 10 determines that the original 2 is being conveyed to the left based on the original position signal. When the original 2 is being conveyed to the right (toward the original guide lb side), the detection output of the light intensity detector 7 is larger than that of the light intensity detector 8 in order to block more light entering the light intensity detector 8. Since the comparator 13 inputs the difference as an original position signal to the microcomputer 10, the microcomputer 10 determines that the original 2 is being conveyed to the right based on the original position signal. If the microcomputer 10 determines based on the input signal from the comparator 13 that the original 2 is not being conveyed to the reference position, it turns on the solenoid 41 and drives the original position correction roller 4 to ensure that the original is at the reference position. The position of the original is corrected until the original position signal is obtained. In order to correct the document 2 so that it is conveyed through the center of the document conveyance path, the detection output of the light amount detector 7.8 should be controlled so that it is the same even when the document is under the light emitting element array 6. good.

FIG. 5 is a flowchart showing the operation when the control section of the above embodiment controls the position of the document at the center of the document conveyance path. When the power of the copying machine is turned on and the preliminary operation is completed, step nl (hereinafter, step ni is simply referred to as ni).
Wait until the copy switch PSW is turned on. P
When SW is turned on, solenoid 31. The motor 30 is turned on, and the document is conveyed toward the document table until it is determined at n3 that the document leading edge detection sensor 9 is turned on (n2). When the document platen leading edge detection sensor 9 detects the leading edge of the document, the timer 14 starts (n4). At this time, the rotation of the motor 30 is maintained, and the document continues to be conveyed along the document conveyance path toward the document table. n5 indicates that timer 14 has timed up.
If so, the motor 30 is turned off (n6). At this time, the leading edge of the document is positioned immediately in front of the conveyor belt 5. Here, compare the detection outputs of the light intensity detectors 7 and 8 (n7). If the detection outputs of both detectors are equal, it is determined that the document is being conveyed in the center of the document conveyance path, and the motor 30 is turned on again and the document is conveyed. The belt 5 is started and conveyance is continued (n8), and the following copy cycle operation begins.

If the detection outputs of light quantity detector 7.8 are not equal at n7,
After determining that the document is not being conveyed through the center of the document conveyance path, the solenoid 31 is turned off to move the conveyance roller 3 away from the document, allowing it to move freely in a direction perpendicular to the conveyance direction, and then the solenoid 41 is turned on. The document position correction roller 4 is brought into pressure contact with the document (n9). Compare the detection outputs of light intensity detectors 7 and 8 using nlo, and if the detection output of light intensity detector 7 is larger, the original is moved closer to light intensity detector 8 (original guide lb).
The document position correction roller 4 is driven by the motor 40 to move the document toward the document guide la side, and the document is moved toward the center of the document path (nil
). If the detection output of the light amount detector 8 is larger as determined by nlo, it is determined that the document is being conveyed closer to the light amount detector 7 (closer to the document guide la), and the document is moved toward the document guide lb side. The document position correction roller 4 is moved by the motor 40.
to move the original toward the center of the original path (n
12). The operation of n11 or n12 is continued until the detection output of the light amount detector 7.8 becomes equal, and if it is determined that both detection outputs are equal (n13), the motor 40 and solenoid 41 are turned off, and the solenoid 31 is turned on. Then proceed to n8 (n14). The original is now corrected to an accurate position and conveyed onto the original table 50.

If you use the automatic document feeder with the above configuration, even if you do not position the document accurately when setting it, the position will be automatically corrected while the document is being conveyed to the document table. Easy to set. In addition, since the position of the original is detected by the difference in the detection output of the light intensity detectors installed at both ends of the original transport path, a large number of optical sensor arrays are used even when setting the original at an arbitrary position. This is not necessary and costs can be kept low.

[Brief explanation of the drawing]

Figures 1 and 2 are a front view and a plan view of an automatic document feeder that is an embodiment of this optical type, Figure 3 is a block diagram of the control section of the above embodiment, and Figure 4 is a schematic diagram of the above embodiment. A side view, FIG. 5 is a flowchart showing the operation of the control unit I of the above embodiment to control the document to the center of the document conveyance path, and FIG. 6 is a conventional automatic document feeder that can control the document to any position. This is a schematic side view of 6-light emitting element array, 7, 8-light amount detector, 9-document leading edge detection sensor, 13-comparator.

Claims (1)

[Claims] (1) A document position detection means provided at a position in front of the document table while the document is conveyed from the document tray to the document table of the copying machine;
an automatic document feeder comprising document position correction means for moving the document to the reference position when the document position detection means detects that the document is not being conveyed to the reference position in a direction perpendicular to the document conveyance direction; The document position detection means includes a document leading edge detection sensor that detects the leading edge of the document, and a document that starts when the document leading edge detection sensor detects the leading edge of the document and transports the document by a predetermined length shorter than the length of the document. a light-emitting element array installed perpendicularly to the document transport path at a position close to the document leading edge detection sensor; It consists of two light intensity detectors, each installed at a position facing the light emitting element array, and detects whether the document is aligned in a direction perpendicular to the document transport direction based on the detection output of each of the two light intensity detectors. An automatic document feeder characterized in that it detects whether or not a document is being conveyed to a reference position.