JPS6261467A - Method for detecting size of original in digital copying machine - Google Patents

Abstract

PURPOSE:To correctly detect the size of an original by reading and measuring the length and the transverse width of a carrying direction of an exposed original carried by an ADF by a CCD image sensor. CONSTITUTION:An original carried on a contact glass 5 is exposed by an exposure lamp 7 and a reflected light forms an image on a CCD image sensor 12 by an optical scanning system 6 and it is successively read. In parallel with the detection of the reach to a home position HP by the CCD image sensor 12, the CCD image sensor 12 reads the length from a leading end to a rear end of the original by measuring the time during which the original is carried by an ADF 3 and passes through the CCD image sensor 12 and measures the length in a direction for carrying the original. AT the same time, the transverse width of the original is read by the CCD image sensor 12. Thereby, the size of the original to be copied is understood.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a document size detection 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 devices are equipped with an automatic document feeder (etc.). and,
Some devices detect the size of a document being conveyed by an ADF in order to automatically select a transfer paper size according to the size of the document to be copied, the copying magnification, etc. Here, in the conventional ADF document size detection method, a plurality of document size detection sensors are arranged and detection is performed according to the on/off states of these sensors. Therefore, as the number of sizes used increases, more sensors are required, the mechanism becomes more complex, and size detection cannot always be performed accurately depending on the conveyance state of the document.

Purpose The present invention was made in view of the above points, and it is an object of the present invention to provide a method for detecting the size of a document in a digital copying machine, which can easily and accurately detect the size of the document without the need for a document size detection sensor. .

Structure In order to achieve the above object, the present invention uses a CCD image sensor for reading the original in a digital copying machine equipped with an ADF that automatically transports the original, and at the start of the copying operation, the optical scanning system is moved to the original home. The apparatus is characterized in that a document is exposed to light while waiting in a position, and the document size is detected by reading and measuring the length and width in the conveyance direction of the document conveyed by the ADF using the CCD image sensor. .

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.
o 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 light amount 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 2o is transferred from the selected one of the paper feeding cassettes 18 and 19 to paper feeding rollers 21 and 22.
The paper is fed by The fed transfer paper 20 is sent toward the photoreceptor 24 at a predetermined timing by the registration rollers 23. A charger 25 is placed around the photoreceptor 24.
, eraser 26, developing device 1127, transfer charger 2
8, static elimination lamps 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 3o, 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 into a visible image by the developing device 27, and transferred onto the transfer paper 2o by the action of the transfer charger 28. The transfer paper 2o on which the toner image has been transferred in this way is separated from the photoreceptor 24,
The image is conveyed by the conveyor belt 33 to the fixing device 34 and fixed. Then, the paper is collated and assembled by the paper ejection roller 35! !
! It is discharged to the 4th side.

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. This ADF 3 feeds the original stacked on the original platen 39 using a paper feeding roller 40, and separates the original into only one sheet using a separation roller 41.
The separated original is detected by the sensor 42, and the separation roller 41 is stopped at the timing when the original comes into contact with the transport roller 43. In this state, the transfer paper 20 is in a standby state, and the conveyance roller 43 is driven by a feed-in signal given from the printer section 1 side to feed the document to the contact glass 5 side.A conveyance belt 44 is provided on the contact glass 5. The document is conveyed over the contact glass 5 by the conveyance belt 44, which is driven together with the conveyance roller 43. 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 discharge roller 45. 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
is a timing and control program for process sequence control such as charging, exposure, development, transfer 1 separation, and cleaning for performing copying operations, and transfer paper conveyance sequence control such as paper feeding of the transfer paper 20, registration alignment, conveyance, ejection, and jam detection. control and other copying machine controls. Polygon mirror & LD controller 5
Reference numeral 5 controls the polygon motor and LD so as to irradiate a predetermined position on the photoreceptor 24 with laser light in synchronization with a digital signal sent from the scanner controller 51.

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 timing and control of document conveyance in the ADF 3, such as feeding, conveying, stopping at the home position HP, and ejecting the document. 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.

With this configuration, in this embodiment, the 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 the print button, the first scanner 13 of the optical scanning system 6 is moved to the hole 11.
The camera is moved to position HP and placed on standby, and the exposure 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 COD image sensor 12 and sequentially read. Therefore, when the rear end of the document reaches the home position HP, this is detected by the COD image sensor 12.

When it is detected that the end of the document has reached the home position HP, the scanner controller 51 gives a signal to the ADF controller 53 to stop the document transport motor. When the ADF 3 receives the stop signal in this way, the motor is immediately stopped and the conveyor belt 44 is stopped.
The original will stop at that position. In this way, the document is positioned and stopped at the hole position HP.

In this embodiment, in parallel with the detection of arrival at the home position HP by the COD image sensor 12, the COD image sensor 12 measures the length from the leading edge to the trailing edge of the original when the original is in the ADF 3. The length of the document in the direction of conveyance is measured by measuring the time it takes for the document to be conveyed and passing through the COD image sensor 12. at the same time,
The CCD image sensor 12 also reads the width of the document. For example, if this CCD image sensor 12 has a rate of 16 elements/m, in the case of an A3 portrait or A4 width document, IG x 297 = 4752 elements will detect the document.
For A4 portrait or A5 width documents, 16X210=3
The width is measured by detecting the document with 360 elements. In this way, by measuring the length and width of the document using the CCD image sensor 12,
You can determine the size of the original you are trying to copy. As a result,
The transfer paper 2o set in the paper feed cassette 18, 19 of the printer section 1 can be appropriately automatically selected according to the document size, copying magnification, etc., and can be 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, and The drive motor for the ADF 12 may be anything that simply rotates.
There is no need to use an expensive C servo motor as in the past, and a significant cost reduction can be achieved. And A
This eliminates the need for multiple document size detection sensors conventionally used in DF, and uses the CCD image sensor 12 for document reading to accurately detect document size, simplifying the mechanism and reducing costs in this respect as well. be able to.

Effects As described above, the present invention uses a CCD image sensor for reading the original to read and detect the length and width of the original to determine the size of the original, so there is no need for multiple sensors for detecting the original size. This makes it possible to easily and accurately detect the size of a document and automatically select an appropriate transfer paper size.

[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. The length and width of this document to be transported in the transport direction are determined by the CC.
A method for detecting document size in a digital copying machine, characterized in that the document size is detected by reading and measuring with a D image sensor.