JPH08317149A - Image forming device - Google Patents

Abstract

PURPOSE: To obtain the image forming device in which an undesired background image is excluded especially from the device reading an original continuously. CONSTITUTION: Automatic density adjustment conducted for a conventional device is executed in real time without preliminary scanning corresponding to continuous reading. A background density is calculated from an image area at the head of the original in the case of continuous reading and data of the background level of video data are replaced into data with an intended density level.

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 having image correction means for reading an image at high speed in a digital copying machine or the like.

[0002]

2. Description of the Related Art Conventionally, in a digital copying machine or the like, a manuscript fed from a manuscript feeding device is fixed by a first mirror stand which is fixed at a home position of the copying machine.
An apparatus has been developed that continuously scans a document as a value image.

[0003]

However, in this type of apparatus, although used for transmitting a fax or the like, the document feeding speed is high and the reader unit cannot be scanned as in the conventional case. , If the background of the original has a constant density color like a newspaper, the background of the output image will be gray, and if it is output as a binary output image, an unnecessary background image will be output. There were cases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of eliminating an unnecessary background image, particularly in an apparatus for continuously scanning a document.

[0005]

SUMMARY OF THE INVENTION According to the present invention, an original feeding means for feeding a plurality of originals, an illuminating means for irradiating and moving the originals, and a continuous reading of the originals being fed. In an image forming apparatus capable of performing the above, a detecting means for detecting the leading edge of a fed document, a timer means for counting a predetermined time after the leading edge passes, and image information for a predetermined time from the leading edge of the document image. Is provided as image processing information, and control means for feeding back the calculated information to the video system of the read image.

[0006]

According to the present invention, the conventional automatic density adjustment is performed in real time without prescanning in correspondence with flow reading, and the background density is calculated from the image area at the beginning of the original at the time of flow reading. Then, based on the data, the background level data of the video data is replaced with the intended density level.

[0007]

1 is a block diagram showing the configuration of an image forming system according to an embodiment of the present invention.

In FIG. 1, a feeding tray 101 is a tray for feeding a document image to the image forming apparatus.
The leading edge detection sensor 115 detects the leading edge of the document image fed by the feeding tray 101.

Further, after a predetermined time has passed after passing through the document leading edge detecting sensor 115, the leading edge of the document reaches the first mirror table 103 moved to the flow reading position. Then, the original that reaches the first mirror table 103 is irradiated onto the photoelectric conversion element 105 via the mirror in the optical path shown in FIG.

The reflected light of the document input to the photoelectric conversion element 105 is output as an analog electric signal, and the A / (not shown)
It is converted into a digital signal by the D converter. The video signal converted into the digital signal is subjected to image processing by an image processor (not shown), and laser emission is controlled as a control signal for the laser unit 106.

The laser light emitted from the laser of the laser unit 106 forms a latent image on the drum 107 via the mirror, and the toner of the developing device 108 is placed on the drum.
It is transferred onto the output paper fed from the paper cassette 113 by the transfer unit 109.

The output sheet transferred by the transfer section 109 is sent to the fixing device 111 by the conveying section 110, and the toner image is thermally fixed on the transfer sheet. The fixed output paper is output to the paper discharge tray 112 and stacked. Also, the unit 11
Reference numeral 4 is for transmitting and receiving a document image read by the image forming apparatus using a telephone line or the like. Also, the document discharge tray 1
Reference numeral 02 is a tray for sequentially ejecting the flow-read originals.

Next, the flow reading operation in this embodiment will be described with reference to FIG. The upper part of FIG. 2 is an example of a document image, and the area 201 shows the background density of the document image. Further, the area 202 is the AE at the time of non-stop scanning.
It is sampled as data. As the operation in the apparatus, the document fed from the feeding tray 101 is
Follow the route shown in the lower part of FIG.
When the document area 202 passes through 03, the background density is calculated.

As a series of operations of this system, as shown in the block diagram of FIG. 3, the original reading information of the photoelectric conversion element 301 is passed through an analog signal processing section (including a CDS, a clamp circuit, a feedback circuit) 302. , A / D converter 303 converts into a video signal. The video signal is input to the data comparator 304.

The data input to the data comparator 304 is sent to the AE background density memory 305 by the AE control signal 306, and the background density subjected to the arithmetic processing is stored. The background density stored in the memory 305 is set again in the comparator 304 by the AE control signal 306, the image data of the original is compared with the data set in the comparator 304, and a value smaller than the comparator set value is arbitrary. Is replaced with a value set to, for example, 0 or the like.

This is because, in the original example shown in FIG. 4, when the image data of the line B crossing the circle and the square and the image line A of the background exist as shown in the figure, the AE of FIG. Later B data can be obtained.

The output passing through the comparator is output to the output device (printer unit) 308 via the image processing unit 307.

Next, FIG. 6 is a flow chart showing the operation at the time of flow reading. In addition, the non-stop reading is usually a fax.
Since it is often used for example, the reading operation of FAX is taken as an example here.

In step S601, the image forming apparatus shown in FIG.
Input settings from the operation screen shown in. On this screen, the FAX number is input by the ten-key pad (not shown) of the operation unit, and the original image is set on the feeding tray 101.

After completion of this setting, the start key is pressed on the operation unit (not shown) to start feeding the original in S602. With respect to the document whose feeding has been started, the counter for calculating the timing to the first mirror stand starts counting by detecting the leading edge detection signal output by the document leading edge detection sensor (S603) (S604). Then, in steps S605 and S606, the first counter counts the arrival time of the document leading edge to the first mirror table.

When the leading edge of the original reaches the first mirror stand, image reading is started from the leading edge of the original, and S60
7, in S608, the second counter counts and the trailing end of the background data is determined. Then, in S609, the calculation of the background density at the leading edge of the document is shown.

The calculated value is set in the comparator and compared with the image data of the document to be read (S61).
1, S612). Then, the comparator output is sent to the image processing unit such as the decoration processing (S615).

If the next original is set in S613, the process returns to S602 to start the feeding of the original, and when the original is exhausted, the reading is finished (S).
614).

Next, FIG. 5 shows an example of an output image when the flow reading is performed. When the picture on the left side of (A) is used as the original, if the AE of the present embodiment is realized as it is, the density during reading the background density of the front end of the original remains unchanged as in the image on the left side of (B). It remains as an unprocessed image. Therefore, it is possible to obtain the image on the right side of (B) by performing processing with the image in the right side of (A) by removing the white image frame, which is a known process for the image forming apparatus.

As a result, as in (C), it is possible to obtain an output image in which only the background data is skipped and the density data of the parts such as circles and squares are stored as they are.

Next, regarding the calculation of the background density data at the leading edge of the document, first, as shown in FIGS. It is possible that a color image is included. Then, in the present embodiment, the average density of one line data of the original or the data in the set designated area is calculated for the purpose of not requiring strict density data and shortening the processing time. And It should be noted that, for further simple calculation, it is possible to substitute the average density of partial pixel data in one line data.

As described above, by adopting the configuration in which the data of the leading edge of the document at the time of flow reading is set and compared in the comparator, the background portion, which has been generally lowered in the density level at the time of executing the AE, is used. It is possible to provide an image forming apparatus that skips only the density of the above and reproduces the density of the effective portion of the document as the image data faithfully to the document.

Next, a second embodiment of the present invention will be described.

As a background density reading method for flow reading, a reader configuration as shown in FIG. 9 is used, and the output of the A / D converter is input to the histogram creating section 901. FIG. 10 is an explanatory diagram showing the range of sampling and histogram creation for a document.

FIG. 10A shows a histogram creation range. When the number of bits for storing the histogram is 16 bits in the sampling for every 1 mm, about 65,000 maximum frequencies can be stored. , A4 size (210 mm × 297 mm) histogram creation range.

FIG. 10B shows the sampling interval. Data is sampled every 16 dots in the main scanning direction and every 16 lines in the sub scanning direction. In the case of flow scanning, the document feeding speed is adjusted to be the same as the speed of one pixel of image data.

By this processing, a histogram as shown in FIG. 11 is created. In this document, a background having the same density (background density) is present in a wide range of an original, and characters and the like are written on the background with a density higher than the background.

The horizontal axis represents the signal level, and the left corresponds to the 0 level (dark) and the right corresponds to the 255 level (bright). The vertical axis represents the frequency, which is usually considered as the ratio (%) of the total frequency. The features of the histogram are: The darkest level of the signal level, 2. Brightest signal level, 3. Level with the highest frequency, 4. Maximum frequency,
4 are obtained, the range of the signal level with the highest frequency corresponds to the background portion (background), and the range from the darkest level of the signal level to the background portion corresponds to the character portion.

The values obtained from this histogram are shown in FIG.
By setting in the data comparator 304, the same effect as the first embodiment can be obtained.

Next, a third embodiment of the present invention will be described.

As a configuration of the automatic density correction device at the time of flow reading, as shown in FIG. 12, the output of the A / D comparator 303 is output to the memory processing device 305 by the selector 1201.
To the data comparator 304 according to the control of the AE control signal 306. The line memory 1202 has a configuration for controlling the data (required section data) to the data comparator 304 and stores the output of the selector 1201 for a predetermined line time. 1202, memory processing device 3
Data is sent from each of the 05.

With this configuration, the same effect as that of the present invention shown in the first embodiment can be obtained, and the data delay of the line memory 1202 causes the data comparator 304 to perform the video of the same line by the background data of the same line. It becomes possible to process the data.

The data timing is as shown in FIG. 13, and the video data 1301 is transferred to the background density data 13 via the background density calculation device 1303.
When calculating 02, a data delay occurs as illustrated.

In order to adjust this delay, the line memory 1304 delays the video data and the data 130.
As shown in FIG. 5, the timing is the same as that of the data 1302. After adjusting the timing, the data comparator 1306
Through this, automatic density adjustment with the same line data is realized. In the case of this embodiment, frame processing may or may not be performed on the output device side.

[0040]

As described above, according to the present invention,
In an apparatus that continuously scans a document, it is possible to eliminate unnecessary background images.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall structure of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a flow-reading operation in the first embodiment.

FIG. 3 is a block diagram showing a configuration of a control system in the first embodiment.

FIG. 4 is an explanatory diagram showing the principle of processing in the first embodiment.

FIG. 5 is an explanatory diagram showing processing at the time of output in the first embodiment.

FIG. 6 is a flowchart showing a flow-reading operation in the first embodiment.

FIG. 7 is a plan view showing a display screen of the operation unit in the first embodiment.

FIG. 8 is an explanatory diagram showing an AE back data calculation process in the first embodiment.

FIG. 9 is a block diagram showing a configuration of a control system in a second embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a background calculation method in the second embodiment.

FIG. 11 is an explanatory diagram showing an example of background calculation in the second embodiment.

FIG. 12 is a block diagram showing a configuration of a control system in a third embodiment of the present invention.

FIG. 13 is a block diagram showing the timing of data in the third embodiment of the present invention.

[Explanation of symbols]

 101 ... Feeding tray, 102 ... Original discharging tray, 103 ... First mirror base, 105 ... Photoelectric conversion element, 106 ... Laser unit, 107 ... Drum, 108 ... Developing device, 109 ... Transfer section, 110 ... Conveying section, 111 ... Fixing device, 112 ... Paper ejection tray, 113 ... Paper cassette, 114 ... Transmission / reception unit, 115 ... Tip detection sensor.

Claims (5)

[Claims] 1. A document feeding means for feeding a plurality of documents,
In an image forming apparatus capable of illuminating and moving a document and continuously reading a document being fed, a detecting unit for detecting the leading end of the fed document and a leading end Timer means for counting a predetermined time from the beginning, calculation means for calculating image information of a predetermined time from the leading edge of the original image as image processing information, and control means for feeding back the calculated information to the video system of the read image. An image forming apparatus comprising: 2. A conversion means for converting image information converted into an electric signal by a photoelectric conversion element into digital data according to claim 1, and comparing the data converted into digital data with the fed-back data, If the image data does not exceed a predetermined level as a result of the comparison, the image forming apparatus further comprises control means for pseudo replacing data at a predetermined level or lower. 3. The image output according to claim 1, further comprising setting means for substituting a pseudo other value as the data to be fed back while the image processing information is being calculated. An image forming apparatus characterized by obtaining. 4. A reading device for calculating image processing information for a predetermined time from the leading edge of a document image and feeding back the read image data, and replacing data in a predetermined area of the read image data with a pseudo value. An image forming apparatus having a control means, wherein an image output is obtained based on the replaced video signal. 5. A plurality of memories capable of storing each line of read data of an original image, setting means for changing a settable parameter on the printer side from background data of the read data, and the background data of the background data. An image forming apparatus comprising: a data storage unit corresponding to a calculation time; and controlling a printer for each line based on read data and background data.