JPS6261468A - Method for controlling original in digital copying machine - Google Patents

Abstract

PURPOSE:To stop an original carrying by an ADF by reading and detecting the reach of an end part of an original exposed and carried by the ADF to a home position by a CCD image sensor. CONSTITUTION:An original carried on a contact glass 5 is exposed by an exposure lamp 7, its reflected light forms an image on the CCD image sensor 6 by an optical canning system 6 and is read successively. When a rear end part of the original reaches to a home position HP, this is detected by the CCD image sensor 12, a signal for stopping an original carrying motor is given from a scanner controller 51 to an ADF controller 53. When the ADF3 receives the stopping signal, the motor is immediately stopped, a carrying belt 44 stops, and the original stops at its position. Thereby, a positioning stop to the home position HP of the original is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a document control method in a digital copying machine.

Conventional technology Conventionally, in order to improve document processing efficiency, copying machines have been equipped with an ADF (ADF) that automatically transports the document to the exposure section and stops it.
Some models are equipped with an automatic document feeder (automatic document feeder). If we look at the document stop control method in conventional ADFs, the document is stopped by counting the number of pulses from the document size detection sensor to the home position using a DC servo motor, which is cumbersome to control. be. or,
Currently, variations in stopping positions due to slippage between the conveyor belt and the document in the ADF have become a problem. Furthermore,
A very expensive motor such as a DC servo motor must be used, resulting in high costs. Additionally, multiple document detection sensors are required.

Purpose The present invention has been made in view of the above points, and an object of the present invention is to provide a document control method in a digital copying machine that can easily stop a document at a predetermined position without using an expensive motor. purpose.

Structure In order to achieve the above object, the present invention provides a digital copying machine equipped with an ADF that automatically transports a document.
A CCD image sensor is used to read the document, and at the start of the copying operation, an optical scanning system is placed on standby at the home position of the document to expose the document, and the end of the document transported by the ADF reaches the home position. It is characterized in that the CCD image sensor detects the reading and stops the document conveyance by the ADF.

Hereinafter, one embodiment of the present invention will be described based on the drawings. First, a digital copying machine to which the present invention is applied will be explained with reference to FIG. This copying machine is roughly divided into printer section 1,
Scanner part 2, ADF 3 and paper collation device (sorter)
4.

Here, the scanner part 2 is provided with a contact glass 5 through which the original is conveyed and set by the ADF 3.
An optical scanning system 6 is provided at the bottom thereof. This optical scanning system 6 includes an exposure lamp 7 that exposes and illuminates the original, a first mirror 8 that receives reflected light from the original, and second and third mirrors 9 and 1.
0 and an imaging lens 11, and is configured to form an image on a CCD image sensor 12 and read an original image. More specifically, the exposure lamp 7 and the first mirror 8 are used as a first scanner 13, and the document surface is scanned by pressing the print button. At this time, the reflected light from the original is imaged on the CCD image sensor 12 via the optical scanning system 6, so that the CCD image sensor 12 sequentially reads the images and converts them into electrical signals. Since the signal from the CCD image sensor 12 is an analog electrical signal, it is converted into a digital electrical signal by the A/D conversion circuit 14 as shown in FIG. Thereafter, the shading correction circuit 15 performs shading correction, that is, correction for variations in the scene distribution of the exposure lamp 7, variations in sensitivity of each light receiving element of the CCD image sensor 12, etc.

Then, processing such as scaling and movement is performed by an image processing circuit 16, and the processed digital signal is separated into a character portion and a halftone portion by a separation circuit 17 and output.

Next, the printer section 1 will be explained. First, the paper feeding system has a two-stage configuration, and the transfer paper 20 is fed from the selected one of the paper feeding cassettes 18 and 19 by paper feeding rollers 21 and 22. The fed transfer paper 20 passes through the registration rollers 23
is sent toward the photoreceptor 24 at a predetermined timing.

Around the photoreceptor 24, a charger 25, an eraser 26, a developing device 27, a transfer charger 28, a discharge lamp 29, etc. are arranged in this order. The process of such printer section 1 will be explained. The laser light is controlled to be turned on and off in accordance with the electric signal (video signal) sent from the scanner part 2 mentioned above.

This laser light is irradiated onto a polygon mirror rotated at high speed by a motor 30, and the reflected light is irradiated onto the photoreceptor 24 via an imaging lens 31 and a mirror 32. At this time, since the photoreceptor 24 is uniformly charged by the charger 25, when it is irradiated with laser light, the surface potential changes depending on the intensity of the light, so that an electrostatic latent image is formed. This latent image is developed by the developing device i! 2
7 to develop into a visible image, which is transferred to the transfer charger 28.
The image is transferred onto the transfer paper 20 by the action of . The transfer paper 20 onto which the toner image has been transferred in this manner is separated from the photoreceptor 24, and is conveyed by a conveyor belt 33 to a fixing device 34 where it is fixed. Then, the paper is discharged to the paper collating device 4 side by the paper discharge roller 35.

In this paper collating device 4, the transfer paper 20 is conveyed by a plurality of rollers 36 and is ejected to a paper receiving shelf (bin) 38 and collated according to the state of the deflection claw 37. Since such a paper collating device is well known, a detailed explanation thereof will be omitted.

Next, the ADF 3 will be explained. In this ADF 3, a document stacked on a document table 39 is sent out by a paper feeding roller 40 and separated into only one sheet by a single separation roller 41.

The separated original is detected by the sensor 42, and the separation roller 41 stops at the timing when this original comes into contact with the transport roller 43. In this state, the transfer paper 20 is in a standby state, and the feed-in signal given from the printer section 1 side A conveyor belt 44 is provided on the contact glass S, and is driven together with the conveyor roller 43, so that the document is brought into contact with the conveyor belt 44. It is conveyed on the glass S. Then, at the timing when the rear end of the document reaches the home position HP, the conveyor belt 44 is stopped and the document is stopped. In this state, as described above, the image is scanned and read by the scanner part 2. When the image reading is completed, the conveyor belt 44 is driven again, and the document is discharged onto the document tray 46 by the conveyor belt 44 and the discharge roller 4S. be done.

Next, a block diagram of the control system is shown in FIG.

Basically, the main controller 50 for the printer section 1
, scanner controller 51, operation unit controller 5
2. ADF controller 53, sorter controller 54
and a polygon mirror & LD (laser diode) controller 55. These controllers 50 to 55 are constituted by a microprocessor, a ROM storing control programs corresponding to each device, a RAM forming a work area, etc., and input/output circuits corresponding to each device. First, the main controller 50
Process sequence control such as charging, exposure, development, transfer, separation, and cleaning for performing copying operations, feeding of transfer paper 20, registration alignment, conveyance, ejection, and JAT1
It performs timing and control program control of transfer paper conveyance sequence control such as detection, and other copying machine controls. The polygon mirror & LD controller 55 synchronizes with the digital signal sent from the scanner controller 51 and controls the polygon motor and LD so as to irradiate a predetermined position on the photoreceptor 24 with laser light.

In addition to image processing as shown in FIG. 2, the scanner controller 51 also controls the motor for driving the optical scanning system 6, the exposure lamp 7, etc. The operation unit controller 52 has an operation unit display (LED, LCD, etc.)
, control key human power, buzzer, etc., and AD
The F controller 53 controls the MW such as feeding, transporting, stopping at the home position HP, and ejecting the original in the ADF 3.
& Performs transport timing and control. Further, the sorter controller 54 controls motors, clutches, solenoids, etc. according to modes sent from the printer section 1, such as a sort mode in which the transfer sheets 20 are collated in page order and a stock mode in which they are sorted by page. be.

In this embodiment having such a configuration, stopping of the document in the ADF 3 is controlled as follows. First, A.D.
When a copying operation is started by setting a document in F3 and pressing a print button, the first scanner 13 of the optical scanning system 6 is moved to the home position HP and placed on standby, and the n-light lamp 7 is turned on. In this state, when a feed-in signal is sent to the ADF 3, the ADF 3 is driven and the feeding and conveyance of the document is started. Thereby, the document conveyed on the contact glass 5 is exposed to light by the exposure lamp 7, and the reflected light is imaged by the optical scanning system 6 on the CCD image sensor 12 and sequentially read. Therefore, when the rear end of the document reaches the position HP, this is detected by the CCD image sensor 12.

When it is detected that the edge of the document has reached the Ho 11 position HP, the scanner controller S1 sends the ADF
A signal is given to the controller 53 to stop the document conveyance motor. When the ADF 3 receives the stop signal in this manner, the motor is immediately stopped, the conveyor belt 44 is stopped, and the document is stopped at that position. In this way, the document is positioned and stopped at the home position HP.

By the way, in parallel with the detection of arrival at the home position HP by the CCD image sensor 12, the CCD image sensor 12 measures the length from the leading edge to the trailing edge of the document.
The document is read by measuring the time it takes for the document to pass through the CCD image sensor 12, and the length of the document in the conveyance direction is measured. At the same time, the CCD image sensor 12 also reads the width of the document. For example, if this CCD image sensor 12 is 16/
m, in the case of an A3 portrait or A4 width document, 16 x 297 = 4752 elements will detect the document, and in the case of an A4 portrait or A5 width document, 16 x 210 elements will be detected.
The width is measured by =3360 elements detecting the document. In this way, the CCD image sensor 12
By measuring the length and width of the document, the size of the document to be copied can be determined. As a result, the transfer paper 20 set in the paper feed cassette 18, 19 of the printer section 1 can be appropriately automatically selected according to the document size, copy magnification, etc., and used for copying.

As described above, according to the present embodiment, it is possible to control the stopping of the document transported by the ADF 3 at the home position HP much more easily than in the conventional method. Also, CC
Since the original is stopped when the edge of the original is detected by the D-image sensor 12, there is no variation in the stopping position due to slipping between the conveyor belt 44 and the original, which has been a problem in the past. , the drive motor in the ADF 12 may simply rotate;
There is no need to use an expensive C servo motor as in the past, and a significant cost reduction can be achieved. Furthermore, A.D.
Various document detection sensors such as a document size detection sensor conventionally used in F are not required, the mechanism becomes simple, and costs can be reduced in this respect as well.

Effects As described above, the present invention uses a CCD image sensor for reading the document to detect when the end of the document reaches the home position and stops the ADF from transporting the document. A document can be easily and accurately stopped at a home position and used for copying using an inexpensive motor without using an expensive drive motor.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a schematic side view, FIG. 2 is a block diagram showing image processing, and FIG. 3 is a block diagram of a control system. 3... Original, 6... Optical scanning system, 12... CCD
image sensor

Claims (1)

[Claims] In a digital copying machine equipped with an ADF that automatically transports a document, a CCD image sensor is used to read the document, and at the start of the copying operation, the optical scanning system is placed on standby at the document's home position, the document is exposed, and the ADF scans the document. A method for controlling a document in a digital copying machine, characterized in that the CCD image sensor reads and detects when the end of the document being conveyed reaches a home position, and the ADF stops conveying the document.