JPH05276306A - Image forming device and image forming method - Google Patents

Abstract

PURPOSE:To implement generation of lots of copies and generation of a single copy continuously without the operation of changeover of a sorter classification/ non-classification mode on each occasion by terminating the sorter classification when the end of classification is discriminated and executing continuously the image forming of originals left in an automatic original sender successively. CONSTITUTION:The software such as calculation procedure, criterion and discrimination procedure is stored in a ROM 32, and a microcomputer 31 discriminates whether or not image forming is to be executed based on setting data called from the ROM 32 and picture data from a picture memory 29. That is, picture information is read from an original, a rate of change in a picture signal is obtained from the read picture information and whether or not the sorter classification is to be terminated is discriminated depending on the quantity of the rate of change. The rate of change in the picture signal is obtained by the total sum of absolute values of differences each resulting from subtracting a value of a center picture element from a value of surrounding picture elements of each division of a pattern sectioned into plural elements, and when the rate of change is smaller than a threshold level, it is discriminated that the classification is finished and the image forming is continued.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a digital copying machine and an image forming method using a copying function.

[0002]

2. Description of the Related Art In a conventional digital copying machine, an automatic document feeder (hereinafter referred to as "ADF") and a sorter are used in combination to copy a desired number of copies from a multi-leaf document.

[0003]

However, in the conventional copying machine, when a single copy is to be created after the multiple copies are created, the all clear key is pressed after confirming that the multiple copy creation operation has been completed. It is necessary to reset the sorter to the non-classification mode, for example. Therefore, the operation procedure to start the next copy (single copy) has to be adopted,
It is time-consuming to create and inefficient.

The present invention provides an image forming apparatus and an image forming method capable of continuously producing a large number of copies and a single copy without operating the sorting / non-sorting mode of the sorter. To aim.

[0005]

In order to solve the above problems, the present invention provides an automatic document feeder for feeding a plurality of sheets of originals one by one onto an original reading table, and an automatic original feeding apparatus for reading the originals on the original reading table. A light source for illuminating, an optical system for forming an image of reflected light from the document, a photoelectric conversion unit for converting an optical image formed by the optical system into an electric signal, and photoelectric conversion by the photoelectric conversion unit. An A / D converter for A / D converting the captured image signal,
An image processing unit for processing the image signal A / D converted by the A / D conversion unit, and a printing unit for forming an image on an image forming medium based on the image signal processed by the image processing unit, In an image forming apparatus having a sorter for sorting the image forming media obtained by this, a display unit, a key input unit, and a control unit for controlling each unit, the optical system via the photoelectric conversion unit. Means for calculating the rate of change of the image signal read by the image processing circuit, and an image storage circuit provided in the image processing unit for temporarily storing the image signal read by the optical system via the photoelectric conversion unit. And a numerical operation circuit for performing a numerical operation based on data stored in advance in the image storage circuit, and a sorting operation of the sorter when the rate of change of the image signal in a calculation result of the numerical operation circuit is below a predetermined threshold value. A determining circuit for determining that terminate,

When the judgment circuit judges that the sorting is completed, the sorting operation of the sorter is finished, and the image forming operation of the original document remaining in the automatic document feeder is continuously executed. Is characterized by.

In the image forming method according to the present invention, when a plurality of sheets of originals are fed one by one onto the original reading table of the automatic original feeding apparatus, and the media on which the images are formed are sorted by a sorter, Image information is optically read from a document, the read optical image is photoelectrically converted, and A / D converted to form an image signal. The rate of change of this image signal is obtained, and this is temporarily stored and stored in advance. Numerical calculation is performed based on the stored data, and when the change rate of the image signal is below a predetermined threshold in the calculation result, it is determined that the sorting operation of the sorter is ended, and the sorting operation of the sorter is performed based on this. After that, the image forming operation of the document remaining in the automatic document feeder is continuously executed.

[0008]

The image information is read from the document, the rate of change of the image signal is obtained from the read image information, and it is determined whether or not the sorting operation of the sorter is ended based on the magnitude of the rate of change. The rate of change of the image signal is obtained as the sum of absolute values of differences obtained by dividing the screen into a plurality of pixels and subtracting the value of the central pixel from the values of the pixels around the screen.

When the obtained rate of change of the image signal is smaller than the threshold value, it is judged that the classification operation is completed, and the classification operation of the sorter is completed. Then, the image forming operation of the document remaining in the automatic document feeder is continuously executed.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, an exposure lamp 7 is movably provided along the original glass 2 of the digital copying machine. The power source 5 of the exposure lamp 7 is connected to the control unit 30 so that the exposure amount is adjusted. Lens 9
Is provided so as to form an image of the exposure illumination on the CCD sensor 11 of the conversion unit 10. Furthermore, the CCD sensor 11
Are connected to the A / D converter 12 and the shading correction circuit 13 in the conversion unit 10.

The A / D converter 12 and the shading correction circuit 13 are connected to the image memory 29 of the image processing section 20. The image memory 29 is connected to the microprocessor 31 of the control unit 30. Software such as a calculation procedure, a judgment standard, and a judgment procedure is written in the ROM 32.
Whether or not to execute image formation is determined based on the setting data called from the image data and the image data from the image memory 29.

A key input section 50 and a display section 60 are connected to the control section 30, and when blank page information or information equivalent thereto is entered, a "original with little information. Do you want to copy? Message is displayed. The operator sees this message,
Press the copy start key 51 to copy, or
The cancel key 52 is pressed to select whether to cancel. Note that copying is automatically stopped after a predetermined time has elapsed from the message display.

In the key input section 50, numeral 53 is a number setting key, numeral 54 is a density setting key, numeral 55 is a density display key, numeral 56 is a document type setting key, numeral 57 is a document type display,
Reference numeral 8 is a magnification setting key, and 59 is a sorter mode setting key.

The image memory 29 is connected to the filter circuit 21. The filter circuit 21 has a function of filtering a signal and performing gamma correction. further,
An ink amount conversion circuit 23 is connected to the filter circuit 21. The filter circuit 21 and the ink amount conversion circuit 23 are respectively provided with a microprocessor 31 of the control unit 30.
Are connected.

Further, the ink amount conversion circuit 23 is connected to the thermal head power source 41 of the printing section 40. Ser
The round head 42 faces the platen drum 46 via the ink ribbon 43 and the paper 44. Next, the operation will be described. When the copy start key 51 of the key input unit 50 is pressed by the operator, the image reading operation is started according to the procedure described below. The light emitted from the exposure lamp 7 illuminates the original 3 on the original glass 2. Light reflected from the original 3 is reflected by the mirror M and the lens 9
An image is formed on the CCD sensor 11 of the conversion unit 10 through.

Photoelectric conversion elements are arranged on the surface of the CCD sensor 11. The image of the document is converted into an electric signal by these photoelectric conversion elements. This image electric signal is amplified by the amplifier in the conversion unit 10 and converted from an analog signal to a digital signal by the A / D converter 12. Next, FIG.
The optical system will be described with reference to. A first carriage 6 is provided immediately below the original glass 2. An exposure lamp 7 and a mirror M are mounted on the first carriage 6. On the other hand, a pair of mirrors M is mounted on the second carriage 70.

The carriage 6 and the carriage 70 are provided so as to be movable along the original glass 2 in the sub-scanning direction. By scanning both carriages 6 and 70, the information of the document 3 is read. At this time, by keeping the scanning speed ratio of 2: 1, the original 3 and the lens 9 are
The length of the optical path LB between them is made constant, and the focus and the projection magnification are maintained.

The image signal converted from an analog signal to a digital signal by the A / D converter 12 normalizes uneven illumination of the exposure lamp 7 and sensitivity variation of the CCD sensor 11 by the shading correction circuit 13 (shading correction).
To be done.

The shading-corrected signal is transferred to the image processing unit 20, subjected to filtering processing and gamma correction by the filter circuit 21, converted into an ink amount signal by the ink amount conversion circuit 23, and transferred to the printing unit 40. To be done.

In the printing section 40, the power supply electric power 41 applied to the thermal head 42 is controlled based on the ink amount signal, and the heat generation amount is adjusted to melt the heat-melted ink 43 on the film to bring it into contact with the image. Ink is transferred to the forming medium (paper) 44 to form an image.

As shown in FIG. 3, the ADF 72 is provided on the upper part of the copying machine. The document feed table 73 of the ADF 72 projects laterally from the upper part of the copying machine. When the originals are set on the original feeding table 73, the originals are fed one by one into the paper feeding section 7
4 and the transport unit 76, and is sent to the original document receiving unit 75 on the upper surface.

As shown in FIG. 4, the document feed table 73 continues from the document feed table 73 through the paper feed section 74 to the transport section 76. Document feeder 7
3 has a tilt holder 73a and a slide 73b. The document is guided to the sheet feeding roller 77 of the sheet feeding unit 74 by the holder 73a and the slide 73b, contacts the empty switch 78, is separated from the following document by the separation roller 79, and further, the jam-1 switch 80 and the aligning roller. The size switch 82 is passed through 81.

The conveyor belt 85 of the conveyor unit 76 is stretched between the pair of pulleys 83 and 84 in parallel with the original glass 2. The conveyor belt 85 is pressed against the original glass at a substantially equal interval by a plurality of pressing rollers 86. Reference numeral 88 is a document stopper, and reference numeral 89 is a U-turn paper discharge roller. The document is sent from the transport unit 76 to the document receiving unit 75 by the U-turn paper discharge roller 89.

As shown in FIG. 5, the sorter 90 is mounted on a caster and detachably provided on the side of the copying machine by latches 91 and 92. The sorter 90 includes a transport section and a sorting section, and the sorting section has a 0th bin 98.
To a 25th bin 99 are provided with a bin frame 97. A transport motor 93 is provided above the sorter 90.
Is provided, and copy sheets are distributed from the inside of the machine to the respective bins via the sheet deflection plate 94 and the lead cam 95. A bin motor 96 is provided below the sorter 90.
Is provided, and the bin frame 97 is moved up and down with a stroke of a predetermined pitch. Next, the processing of the read image data will be described in detail with reference to FIGS. The signal subjected to shading correction by the shading correction circuit 13 is temporarily stored in the image memory 29 of the image processing unit 20.

The image memory 29 is designed so that it can be accessed by the microprocessor 31 of the control unit 30, and the microprocessor 31 performs numerical calculation processing of image data to calculate the rate of change E of the image signal.

As shown in FIG. 6, the rate of change E of the image signal
Is calculated as a sum of absolute values of values obtained by subtracting the value of the central pixel P1 from the values of the peripheral pixels P2 to P9 using the following equation (1).

[0028]

[Equation 1] However, the symbol N is a number excluding the end pixels from all the pixels.

Change rate E of the image represented by the above equation (1)
Should have a value of 0 when the original image has a uniform reflection density (that is, for a plain original), but normally it is mixed into the sampling error and the signal system during A / D conversion of the image signal. A non-zero value is shown because of the noise component.

Therefore, a threshold value T is set, and when E <T or less, it is determined that the information amount of the document is smaller than the prescribed value, and the display unit 6
At 0, a recommendation to stop the image forming operation is displayed. The operator presses the stop key 52 of the key input unit 50 when it is judged that copying is not necessary by looking at the display, and the copy start key 51 of the key input unit 50 is pressed when it is judged that copying is necessary. .. A method of setting the threshold T will be described.

The white reference plate 4 is placed on the original glass 2, and the signal corresponding to the image information read from this is stored in the image memory 29. The threshold value T is set based on this. In this case, the zero reference may be used as the threshold T as it is, or a value obtained by adding an appropriate amount of image information to the zero reference may be used as the threshold T. This device has a key input unit 6
When the 0 stop key 52 is pressed, the image forming operation in the printing unit 40 is stopped. This device has a key input unit 50.
When the copy start key 51 is pressed, the image forming operation in the printing unit 40 is executed. The calculation procedure, the determination standard, and the determination procedure are written in the ROM 32 of the control unit 30.

In this embodiment, the arithmetic operation is performed by the microprocessor 31, but the present invention is not limited to this, and it is possible to shorten the arithmetic time by using another arithmetic circuit. It is also possible to wait for a certain time for key input by performing a counting operation in the microprocessor 31. Next, the operation will be described with reference to FIGS. 1, 2 and 7.

The multi-leaf originals 3 are set on the original feed table 73 of the ADF 72. The sorter mode setting key 59 of the key input unit 50 is pressed to set the sorter mode in which each original is copied by the desired number of copies and is sorted (step 101). When you press the copy start key 51, follow the procedure below.
The image reading operation is started.

The original 3 on the original feeding table 73 is detected by the sensor, and it is determined whether or not the original 3 exists on the original feeding table 73 (step 102). When the document 3 is on the table 73, the copy operation in the sorter mode is executed, and when there is no document remaining, the copy operation is ended.

The lowermost one of the originals 3 of a plurality of leaves (all P pages) on the paper feed tray 73 is fed onto the original reading tray (original glass) 2 by the conveyor belt 85 (step 10).
3). The first and second carriages 6 and 70 move in the sub-scanning direction, respectively, and the exposure lamp 7 irradiates the original 3 on the original glass 2 with light (step 104).

The reflected light from the original 3 is optically read as image information. That is, the reflected light from the original 3 is imaged on the CCD sensor 11 through the mirror M and the lens 9.

Photoelectric conversion elements are arranged on the surface of the CCD sensor 11. An image of the original is converted into an electric signal by the photoelectric conversion element, the electric image signal is amplified by an amplifier, and converted from an analog signal to a digital signal by the A / D converter 12. The exposure lamp 7 and the mirror M are the first
It is on the carriage 6, and the other pair of mirrors M is the second
It is on the carriage 70.

Each of the first and second carriages 6 and 70 scans the original 3 in the sub-scanning direction. At this time, by keeping the speed ratio of 2: 1, the optical path length between the original 3 and the lens 9 is made constant, and the focus and the projection magnification are maintained.

In the image signal converted from the analog signal to the digital signal by the A / D converter 12, the shading correction circuit 13 normalizes the illumination unevenness of the exposure lamp 7 and the sensitivity variation of the CCD sensor 11 (shading correction).
To be done.

The shading-corrected signal is transferred to the image processing section 20 and stored in the image memory 29 (step 105). Further, the shading correction signal is subjected to filtering processing and gamma correction by the filter 21, converted into an ink amount signal by the ink amount conversion circuit 23, and transferred to the printing section 40.

The printing section 40 controls the power source 41 applied to the thermal head 42 based on the ink amount signal,
The heat-melting ink 43 on the film is melted by adjusting the amount of heat generation, and the ink is transferred to the image forming medium 44 that is in contact with this.

On the other hand, the microprocessor 31 calls the image data stored in the image memory 29 and calculates the change rate E of the image signal. Microprocessor 31
Determines whether the original is plain (blank) based on the calculation result (step 106).

If the rate of change E of the image signal is equal to or higher than the threshold value T, it is determined that the image is not plain and copying is repeated in the sort mode as it is (step 109). That is, the process returns from the step 109 to the step 102, and the step 10
A series of operations from 2 to step 106 are repeated. The copy operation in the sort mode will be described. The image forming medium 44 obtained in the machine body is sent to the sorter 90 and loaded in the first bin. Similarly, the second image forming medium 44 is loaded in the second bin of the sorter, and the Nth image is loaded in the Nth bin of the sorter.

Thereafter, the ADF 72 ejects the original 3 on the original glass, and at the same time, the lowermost one of the plural sheets of original 3 on the ADF 72 is fed onto the original glass 2, and the above procedure is followed. The second leaf is copied and even all P pages are copied. as a result,
One set of copies is made in bins 1 to N of the sorter.

By the way, a blank sheet 4 is placed on the original 3 of the P page.
(Or plain paper) and the next original 3 (all Q pages) are set, that is, when a blank paper 4 (or plain paper) is set on the original glass 2 by the ADF 72, a blank paper ( Alternatively, it is detected that the document is a plain paper document, and the sorter 90 finishes the sorting operation, and the subsequent image forming medium 44 is loaded in the 0th bin 98 of the sorter 90.

That is, when the rate of change E of the image signal is below the threshold value T, the original is determined to be plain (blank) and the sorting mode is switched to the non-sorting mode (step 10).
7). Then, copying is repeated in the non-sort mode (step 108). The detection of the blank document 4 will be described in more detail. The signal subjected to shading correction by the shading correction circuit 13 is temporarily stored in the image memory 29.

The image memory 29 is designed so that it can be accessed by the microprocessor 31 of the control unit 30, and the microprocessor 31 performs numerical calculation processing of image data to calculate the change rate E of the image signal. The rate of change E of the image signal is calculated based on the above equation (1).

The change rate E of the image represented by the equation (1) is
If the original image has a uniform reflection density, that is, if it is a plain original such as a blank sheet, it should be zero, but normally, a sampling error at the time of A / D conversion of the image signal or a noise component mixed in the signal system. Indicates a non-zero value for. Therefore, it is necessary to make the threshold T correspond to data having a certain amount of information.

[0049]

According to the present invention, the operation of the sorter can be ended without interrupting the image forming operation with a relatively simple structure.

[Brief description of drawings]

FIG. 1 is an image processing block diagram of a digital copying machine according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an optical system of a digital copying machine.

FIG. 3 is a perspective view showing the appearance of an ADF.

FIG. 4 is a vertical sectional view showing a front portion.

FIG. 5 is a partial cross-sectional view showing the outline of a sorter.

FIG. 6 is a diagram schematically showing a pixel for explaining a rate of change of an image signal.

FIG. 7 is a flowchart showing an image forming method according to an embodiment of the present invention.

[Explanation of symbols]

7 ... Light source, 12 ... A / D conversion unit, 20 ... Image processing unit, 2
9 ... Image storage circuit, 30 ... Control section, 31 ... Numerical value calculation circuit, 32 ... Judgment circuit, 40 ... Printing section, 50 ... Key input section, 60 ... Display section, 72 ... ADF, 90 ... Sorter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H04N 1/04 107 B 7251-5C 1/40 Z 9068-5C

Claims (2)

[Claims] 1. An automatic document feeder for feeding a plurality of sheets of originals one by one onto an original reading stand, a light source for illuminating the original on the original reading stand, and an image of reflected light from the original. An optical system, a photoelectric conversion unit that converts an optical image formed by this optical system into an electric signal, and an A / D conversion unit that A / D converts the image signal photoelectrically converted by this photoelectric conversion unit. An image processing unit that processes the image signal A / D converted by the A / D conversion unit; and a printing unit that forms an image on an image forming medium based on the image signal processed by the image processing unit. In the image forming apparatus having a sorter for classifying the image forming media obtained by this, a display unit, a key input unit, and a control unit for controlling each unit, the optical unit is provided via the photoelectric conversion unit. Calculate the rate of change of the image signal read by the system Means, an image storage circuit provided in the image processing unit for temporarily storing an image signal read by the optical system via the photoelectric conversion unit, and previously stored in the image storage circuit. A numerical operation circuit for performing numerical operation based on data; a decision circuit for deciding to terminate the sorting operation of the sorter when the change rate of the image signal in the calculation result of the numerical operation circuit is below a predetermined threshold value; And a circuit for ending the sorting operation of the sorter and continuing the image forming operation of the original document remaining in the automatic document feeder when the circuit determines that the sorting operation is completed. Forming equipment. 2. When a plurality of sheets of originals are fed one by one onto an original reading table of an automatic original feeder, and when image formed media are sorted by a sorter, image information is optically transmitted from the originals. Read, photoelectrically convert the read optical image, and further A / D convert it into an image signal, obtain the rate of change of this image signal, temporarily store and store this, and perform numerical calculation based on pre-stored data. However, if the result of this calculation shows that the rate of change of the image signal is below a predetermined threshold value, it is determined that the sorting operation of the sorter should be terminated, and based on this, the sorting operation of the sorter is terminated and the automatic document feeding is continued. An image forming method, characterized in that an image forming operation of an original document remaining in the apparatus is continuously executed.