JPH0522532A - Image forming device - Google Patents

Abstract

PURPOSE:To quickly and accurately adjust the deviation of an original in the reading position by correcting data representing the position of the read original picture according to the difference between the data representing the position of the picture for adjustment original and the prescribed position data. CONSTITUTION:When a print switch is turned on, whether an original is set in an RDF or in an original mounting plate is discriminated. In the case of the RDF, a scanner is stopped at the prescribed position below the RDF and the original is carried. In the case of the mounting plate, the original picture is read by moving a scanner along the lower surface. The picture data is sent from an image sensor 22 to a picture data input part 61 so as to perform picture processing. After that, correction data x1 and x2 to be used for the adjustment at the time of reading are read out according to the original picture reading position stored in a memory 64, and the deviation of the original is corrected to be stored in the memory 64. Thus, the deviation of the original in the reading position can quickly and accurately be adjusted.

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 for forming a document image on a sheet.

[0002]

2. Description of the Related Art An image forming apparatus such as a digital copying machine reads an original image by a scanner, temporarily stores the image data of the original in a readable / writable memory, and if necessary, various kinds of image data are added to the image data in an image processing section. After processing, the image data is stored again in the memory, the processed image data is read out, and a visible image is formed on a sheet in an image forming unit such as a laser printer.

Some conventional digital copying machines are equipped with a double-sided automatic document feeder (RDF). In such a digital copying machine, the lower surface of the document table on which the document is placed is located. It is possible to read the original image while the scanner is moving along it, or to read the original image with the scanner while conveying the original by RDF with the scanner stopped at a predetermined position below the RDF.

[0004]

In such a conventional image forming apparatus, when the RDF is attached, the original fed to the predetermined reading position of the original image is adjusted so as not to be displaced in the conveying direction. Then need to be installed.
However, there is a problem that such an operation for adjustment is complicated and requires time and effort.

Therefore, it is an object of the present invention to provide an image forming apparatus capable of quickly, easily and accurately adjusting the deviation of a document at a position where the image of the document is read.

[0006]

A document reading unit for reading an image of a document and a document reading unit according to a difference between data representing a position of an image of an adjustment document read by the document reading unit and predetermined position data. The image forming apparatus includes a correction unit that corrects data representing the position of the image of the document to be read, and an image forming unit that forms an image on which the data representing the position is corrected by the correction unit.

[0007]

According to the difference between the data representing the position of the image of the adjustment document read by the document reading unit and the predetermined position data, the correcting unit represents the position of the normal image of the document read by the document reading unit. The data is corrected, and the corrected image is formed on the sheet by the image forming means. Therefore, it is possible to quickly, easily and accurately adjust the deviation of the document at the position where the image of the document is read.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. Here, an example in which the image forming apparatus according to the present invention is applied to a digital copying machine will be described.

FIG. 2 is a sectional view showing the overall construction of a digital copying machine which is an embodiment of the image forming apparatus according to the present invention.

As shown in FIG. 1, the digital copying machine 10 of this embodiment is provided with a scanner section 11, a laser printer section 12, a multi-stage sheet feeding unit 13 and a sorter 14.

An RDF 15 is installed above the scanner unit 11. The scanner unit 11 includes a document table 16 made of transparent glass, a movable scanner unit 17, and a position control device for controlling the position of the scanner unit 17. It is configured.

This position control device is a scanner unit.
The position control device includes a scanner motor 18 for driving the motor 17, a pulley 19, and a wire 20 stretched between the scanner motor 18 and the pulley 19, and the position control device moves the scanner unit 17 along the longitudinal direction of the document table 16. It is configured so that it can be moved and stopped at a predetermined position.

The scanner unit 17 includes a lamp reflector assembly 21 for exposing a document, a CCD (photoelectric conversion element) linear image sensor 22, and a plurality of reflecting mirrors 2 for guiding a reflected light image from the document to the CCD linear image sensor 22.
3 and a lens 24 for forming a reflected light image from the original on the CCD linear image sensor 22.

When scanning an original placed on the original placing table 16, the scanner section 11 reads the original image while the scanner unit 17 moves along the lower surface of the original placing table 16 and uses the RDF 15. In this case, the document image is read while the document is being conveyed while the scanner unit 17 is stopped at a predetermined position below the RDF 15.

The image data obtained by reading the original image with the scanner unit 17 is subjected to various kinds of processing by an image processing control unit, which will be described later, included in the digital copying machine 10. The image is temporarily stored in a memory provided therein, and image data in the memory is given to the laser printer section 12 in accordance with an output instruction to form an image on a sheet.

The multi-stage paper feeding unit 13 includes a first cassette 28,
It has a second cassette 29, a third cassette 30, and a fourth cassette 31 that can be added by selection. In the multi-stage paper feeding unit 13, the papers are sent out one by one from the papers stored in these cassettes, and are conveyed toward the laser printer unit 12.

The laser printer unit 12 is a manual document tray 2
5. A laser writing unit 26 and an electrophotographic process unit 27 for forming an image are provided.

The laser writing unit 26 is a semiconductor laser which emits a laser beam according to the image data from the above-mentioned memory, a polygon mirror which deflects the laser beam at a constant angular velocity,
It has an f-θ lens or the like for correcting so that the laser beam deflected at a constant angular velocity is deflected at a constant velocity on the photoconductor drum 27a of the electrostatic photography process section 27.

The electrophotographic process section 27 comprises a charging device, a developing device, a transfer device, a peeling device, a cleaning device, a static eliminator and a fixing device 32 around the photosensitive drum 27a in a known manner. ..

A transport path 33 is provided downstream of the fixing device 32 in the transport direction of the sheet on which an image is to be formed.
33 is a transport path 34 leading to the sorter 14 and a multi-stage paper feeding unit
It branches off to a conveyance path 35 leading to 13.

The conveyance path 35 is branched in the multi-stage paper feeding unit 13, and a reversal conveyance path 36 and a double-sided / composite conveyance path 37 are provided as the conveyance paths after branching.

The reverse conveyance path 36 is a conveyance path for reversing the front and back sides of a sheet with respect to the image forming position of the photosensitive drum 27a in the double-sided copy mode for copying both sides of a document. The duplex / composite transport path 37 is the reverse transport path in the duplex copy mode.
The paper is conveyed from 36 to the image forming position on the photosensitive drum 27a, or the image of a different original or the image of different color toner is formed on one side of the paper. A transport path for transporting to the image forming position of the drum 27a.

The multi-stage paper feeding unit 13 includes a common conveyance path 38, and the common conveyance path 38 transfers the papers from the first cassette 28, the second cassette 29 and the third cassette 30 to the electrophotographic process section 27. It is configured to be carried out toward.

The common transport path 38 joins the transport path 39 from the fourth cassette 31 on the way to the electrophotographic process section 27 and communicates with the transport path 40.

The conveying path 40 merges with the double-sided / composite conveying path 37 and the conveying path 41 from the manual document tray 25 at a confluence point 42 to form an image between the photoconductor drum 27a of the electrostatographic process section 27 and the transfer device. It is configured to reach the formation position.
The confluence point 42 of the two conveyance paths is provided at a position close to the image forming position.

Therefore, in the laser writing unit 26 and the electrophotographic process section 27, the image data read from the above-mentioned memory is scanned by the laser beam by the laser writing unit 26, and the photosensitive drum 27a.
The toner image formed as an electrostatic latent image on the surface of the sheet is visualized by the toner, and is electrostatically transferred and fixed on the surface of the sheet conveyed from the multi-stage sheet feeding unit 13. The sheet on which the image is formed in this way is fed from the fixing device 32 to the conveying paths 33 and 34.
It is sent to the sorter 14 via the, or is transported to the reversing transport path 36 via the transport paths 33 and 35.

Next, the control system of the digital copying machine 10 shown in FIG. 2 will be described.

FIG. 3 is a block diagram showing the configuration of the control system of the digital copying machine 10 shown in FIG. In the figure, thick arrows between blocks indicate the flow of image data, and solid arrows indicate the flow of control signals.

As shown in the figure, the digital copying machine includes a control system for controlling its operation. This control system includes a central control unit 51, an image input unit 52, an image processing unit 53, and an image output unit. 54, an operation panel unit 55, a scanner control unit 56, a desk unit 57, and a sorter unit 58.

The central control unit 51 is a central processing unit (CP
U), and controls the image processing unit 53, the operation panel unit 55, the scanner control unit 56, the desk unit 57, and the sorter unit 58 by communication so as to integrally control each unit of the digital copying machine. Is configured.

The image input section 52, the image processing section 53 and the image output section 54 constitute an image processing control section for performing processing from inputting to outputting of image data in the digital copying machine,
These configurations and functions will be described later.

The operation panel section 55 includes a display section using liquid crystal,
It is composed of a touch sensor and a switch, which are overlaid on this display section, and these display section, touch sensor and switch are exclusively included in the operation panel section 55 in response to a command from the central control section 51. Controlled by the CPU.

The scanner control unit 56 is a control unit for controlling the scanner unit 11 shown in FIG. 2 for reading a document image, the RDF 15 for conveying the document to a predetermined document reading position, and more specifically, the scanner unit. 17 round trips, CC
It is configured to control the timing of reading an original image by the D linear image sensor 22 and the timing of original feeding by the RDF 15. These controls are performed by a dedicated CPU included in the scanner control unit 56 according to a command from the central control unit 41.

The desk portion 57 is a multi-stage paper feeding unit shown in FIG.
Control of the conveyance of the paper from the cassette 13 and the manual feed tray 25 to the laser printer unit 12 and the conveyance of the paper on the reverse conveyance path 36 and the double-sided / composite conveyance path 37 in the double-sided copy mode by a command from the central control unit 41 Is configured to.

The sorter unit 58 controls the sorter 14 shown in FIG. 2 so that sheets formed with images are sorted and grouped according to the mode designated by the operator via the touch sensor of the operation panel unit 55. Is configured.

Next, the processing from the input of image data to the output will be described.

FIG. 4 is a block diagram of an image processing control unit included in the digital copying machine 10 shown in FIG. 2 and which performs processing from input to output of image data.

As shown in the figure, the image processing control unit includes an image data input unit 61, an image data processing unit 62, an image data output unit 63, a memory 64 including a RAM (random access memory), and a CPU 65. There is.

Image data input unit 61, image data processing unit 62
The image data output unit 63 is configured to correspond to the image input unit 52, the image processing unit 53, and the image output unit 54 of FIG. 3, respectively. Therefore, the image data processing unit 62 is connected to the central control unit 51 shown in FIG. 3 via the CPU 65, and the operation of the image processing control unit is controlled by the central control unit 51 and the CPU 65.

The image data input section 61 includes a CCD section 61a, a histogram processing section 61b and an error diffusion processing section 61c.

The image data input unit 61 binarizes and converts the image data of the original read from the CCD linear image sensor 22 of FIG. 2 to obtain a histogram as a binary digital amount, and the image data by the error diffusion method. Is processed and stored in the memory 64 once.

That is, in the CCD section 61a, after the analog electric signal corresponding to each pixel density of the image data is A / D (analog / digital) converted, MTF correction, black and white correction or gamma correction is performed, and the 256th floor It is output to the histogram processing unit 61b as a key (8-bit) digital signal.

In the histogram processing section 61b, the CCD section 61
The digital signal output from a is added for each pixel density of 256 gradations to obtain density information (histogram data), and if necessary, the obtained histogram data is sent to the CPU 65 or pixel error It is sent to the diffusion processing unit 61c.

The error diffusion processing section 61c performs an error diffusion processing which is a kind of pseudo halftone processing. That is, in the error diffusion processing unit 61c, the digital signal of 8 bits / pixel output from the CCD unit 61a is converted into 1 bit (binary) by the method of reflecting the binarization error in the binarization judgment of the adjacent pixel. The redistributed calculation is performed in order to faithfully reproduce the density of the local area in the original that has been converted.

The image data processing unit 62 includes multi-valued processing units 62a and 62b, a synthesis processing unit 62c, a density conversion processing unit 62d, a scaling processing unit 62e, an image processing unit 62f, an error diffusion processing unit 62g and a compression processing unit 62h. Is included.

The image data processing unit 62 is a processing unit for finally converting the input image data into image data desired by the operator, and stores it in the memory 64 as output image data obtained by finally converting the image data. Until this is done, processing is performed in this processing unit.

Each processing unit included in the image data processing unit 62 functions as necessary, and the function may not be executed in some cases.

In the multilevel halftoning processing units 62a and 62b, the data binarized by the error diffusion processing unit 61c is converted again into 256 gradations.

In the synthesizing section 62c, a logical operation for each pixel,
That is, the operation of logical sum, logical product, or exclusive logical sum is selectively performed. The data that is the target of this calculation is the pixel data stored in the memory 64 and the bit data from the pattern generator (PG).

In the density conversion processing unit 62d, the relationship between the input density and the output density is arbitrarily set for the digital signal of 256 gradations based on a predetermined gradation conversion table.

In the scaling processing unit 62e, pixel data (density value) for the target pixel after scaling is obtained by performing an interpolation process with known data that is input according to the designated scaling ratio. After the scanning is scaled, the main scanning is scaled.

In the image processing unit 62f, various image processings may be performed on the input pixel data to collect information on the data string such as feature extraction.

The error diffusion processing section 62g performs the same processing as the error diffusion processing section 61c of the image data input section 61.

In the compression processing section 62h, binary data is compressed by the encoding called run length. Regarding the compression of the image data, the compression functions in the final processing loop when the final output image data is completed.

The image data output unit 63 includes a restoration unit 63a, a multi-value quantization processing unit 63b, an error diffusion processing unit 63c, and a laser output unit 63d.
Is included.

The image data processing unit 63 is a memory in a compressed state.
The image data stored in 64 is restored, converted back to the original 256 gradations, and the error diffusion of the 4-valued data, which is a smoother halftone expression than the binary data, is performed, and the data is output to the laser output unit 63d. Is configured to forward.

That is, the decompression unit 63a decompresses the image data compressed by the compression processing unit 62h.

In the multi-value processing section 63b, the image data processing section
Processing similar to that of the multi-value quantization processing units 62a and 62b of 62 is performed.

The error diffusion processing unit 63c performs the same processing as the error diffusion processing unit 61c of the image data input unit 61.

In the laser output section 63d, the digital pixel data is converted into an ON (ON) / OFF (OFF) signal for driving the laser based on the control signal from the central control section 51, and the laser is turned ON / OFF. It becomes a state.

The data handled by the image data input unit 61 and the image data output unit 63 is basically stored in the memory 64 in the form of binary data in order to reduce the capacity of the memory 64. It is also possible to process in the form of four-valued data in consideration of deterioration of image data.

The scanner section 11 in FIG. 2 is an embodiment of the document reading means of the present invention. The laser printer unit 12 of FIG. 2 is an embodiment of the image forming means of the present invention. The central control unit 51 of FIG. 3 and the CPU 65 of FIG. 4 are an embodiment of the correction means of the present invention.

Next, the operation of adjusting the deviation of the document at the document reading position in the digital copying machine of this embodiment will be described.

FIG. 5 is a flowchart showing an operation for obtaining correction data used for adjusting the deviation of the original at the original reading position in the digital copying machine 10 of FIG. 2, and FIG. 6 shows an image of the original conveyed by the RDF. 8 is an explanatory view showing a format original used for adjustment when reading by the scanner unit, FIG. 7 is an explanatory view showing a format original used for adjustment when the image of the original placed on the original placing table is read by the scanner unit, and FIG. FIG. 5 is an explanatory diagram showing a comparison between position data of a center reference line in a storage area of the memory 64 of FIG. 4 and position data of a reference line of a read format document.

The control of the operation shown in the flowchart of FIG. 5 is executed by the central control unit 51 shown in FIG.

First, when a print switch on an operation panel (not shown) provided in the digital copying machine 10 of FIG. 2 is pressed (step ST1), the document tray (not shown) of the RDF 15 of FIG. Format Manuscript 71 shown in
Whether or not is set is determined by a document size detecting device (not shown) provided on the document tray (step ST2).

If it is determined in step ST2 that the formatted document 71 is set on the document tray of the RDF 15, the process proceeds to step ST4, and if it is determined that the formatted document 71 is not set, the process proceeds to step ST3.

In step ST3, whether or not the format original 72 shown in FIG. 7 is set on the original placing table 16 of FIG. 2 is determined by an original size detecting device (not shown) provided on the original placing table 16. To be done.

In step ST3, if it is determined that the format document 72 is set on the document table 16, the process proceeds to step ST4, and if it is determined that the format document 72 is not set, the operation ends.

As shown in FIGS. 6 and 7, the format originals 71 and 72 have reference lines 71a and 71a at the center of the originals.
72a are drawn respectively.

When the format original 71 is set on the original tray of the RDF 15, the reference line 71a of the format original 71 is set so as to be parallel to the original conveying direction by the RDF 15 at a predetermined original reading position. Further, when the format original 72 is set on the original placing table 16, the reference line 72a of the format original 72 is set so as to be parallel to the scanning direction of the scanner unit 17 in FIG.

As shown in FIG. 5, in step ST4, the image of the formatted original 71 or 72, that is, the reference line 71a or 72a is read by the scanner unit 17 of FIG.

The image data of the read format original is sent from the CCD linear image sensor 22 to the image data input section 61 of FIG.
After the binarization, the histogram processing, and the error diffusion processing, they are stored in the memory 64 (step ST5), and the process proceeds to step ST6.

Then, in step ST6, as shown in FIG. 8, the position data of the center reference line 81a in the storage area 81 stored in advance in the memory 64 and the format original data read and stored in the memory 64 are stored. A comparison is made with the position data of the reference line 82. That is, the address data at the position of the central reference line 81a in the storage area of the memory 64 according to the size of the formatted document is sent from the central control unit 51 of FIG. 3 to the CPU 65, and the image data processing unit 62 responds to this address data. The difference between the position data of the central reference line 81a in the storage area of the memory 64 and the position data of the reference line 82 of the formatted document stored in the memory 64 is obtained.

Difference data x thus obtained
Is an amount representing the deviation of the center line of the document that should be at the position of the broken line shown in FIG. 8, and is stored in the memory 64 as correction data of the document deviation.

Here, the size of the formatted document can be detected by a document size detection device (not shown) provided on the document tray of the RDF 15 and the document table 16 of FIG.

Therefore, when step ST6 is finished, RDF
The correction data x ₁ of the deviation of the original used for the adjustment when the image of the original conveyed by the scanner unit is read by the scanner unit and the adjustment when the image of the original placed on the original placing table 16 are read by the scanner unit. The correction data x ₂ of the misalignment of the original used is stored in the memory 64.

In the above embodiment, the format originals 71 and 72 are described separately for convenience of explanation, but the format original used for adjustment when reading the image of the original conveyed by the RDF and the original placed on the original table. The format original used for adjustment when reading the image of the placed original is
It may be the same document.

Next, an operation of correcting the image data of the read original on the basis of the correction data x ₁ and x ₂ of the deviation of the original stored in the memory 64 when the actual original image is read will be described.

FIG. 1 is a flow chart showing the operation of adjusting the deviation of the document at the document reading position in the digital copying machine which is one embodiment of the image forming apparatus according to the present invention.

The operation of adjusting the deviation of the original at the original reading position is performed by the central controller 51 of FIG. 3 and the CPU of FIG.
Controlled by 64.

As shown in FIG. 1, first, when a print switch on an operation panel (not shown) provided in the digital copying machine 10 of FIG. 2 is pressed (step ST11), the RDF 15 of FIG. 2 is shown. Whether or not a document is set on a document tray that is not installed is determined by a document size detection device (not shown) provided on the document tray (step ST12).

In step ST12, if it is determined that the document is set on the document tray of the RDF 15, the process proceeds to step ST14, and if it is determined that the document is not set, the process proceeds to step ST13.

In step ST13, whether or not a document is set on the document mounting table 16 of FIG. 2 is determined by a document size detecting device (not shown) provided on the document mounting table 16.

If it is determined in step ST13 that the document is set on the document table 16, step ST
If it is determined that it is not set, the operation is ended.

At step ST14, the original image is read by the scanner unit 17 shown in FIG. 2, and the process proceeds to step ST16.

Next, in step ST16, the image data of the read original is sent from the CCD linear image sensor 22 to the image data input section 61 of FIG.
Binarization, histogram processing, and error diffusion processing are performed by 61. After that, when the processed image data is stored in the memory 64, the correction data x ₁ used for adjustment when reading the image of the original document conveyed by the RDF 15 stored in the memory 64 is read out, and the correction data x ₁ is read out. The deviation of the document is corrected based on x _1, and the process proceeds to step ST17.

Next, in step ST17, the corrected image data is stored in the memory 64.

On the other hand, in step ST15, the original image is read by the scanner unit 17 shown in FIG.
Proceed to 18.

Next, in step ST18, the image data of the read original is sent from the CCD linear image sensor 22 to the image data input section 61 of FIG.
Binarization, histogram processing, and error diffusion processing are performed by 61. After that, when the processed image data is stored in the memory 64, the correction data x ₂ used for adjustment when reading the image of the document placed on the document placing table 16 stored in the memory 64 is read out. Then, the deviation of the document is corrected based on the correction data x ₂ , and the process proceeds to step ST19.

Next, in step ST19, the corrected image data is stored in the memory 64.

Therefore, the corrected image data stored in the memory 64 is sent to the image data output unit 63, so that the image formed on the sheet is free from the image distortion due to the document deviation, It is possible to obtain various copied images.

According to the above-described embodiment, the deviation of the original at the position where the image of the original is read can be adjusted quickly, easily and accurately. This is RD
It is especially effective when F is attached to a digital copying machine.

[0094]

As described above, according to the present invention, the document reading means for reading the image of the document, the data representing the position of the image of the adjustment document read by the document reading means, and the difference between the predetermined position data are used. Since the correction unit that corrects the data representing the position of the image of the document read by the document reading unit and the image forming unit that forms the image on which the data representing the position corrected by the correction unit is corrected on the sheet, Therefore, the deviation of the document at the position where the image of the document is read can be adjusted quickly, easily and accurately.

[Brief description of drawings]

FIG. 1 is a flowchart showing an operation of adjusting a deviation of a document at a document reading position in a digital copying machine which is an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing the overall configuration of a digital copying machine that is an embodiment of the image forming apparatus according to the present invention.

3 is a block diagram showing a configuration of a control system of the digital copying machine of FIG.

FIG. 4 is a block configuration diagram of an image processing control unit included in the digital copying machine of FIG. 2 that performs processing from input to output of image data.

5 is a flowchart showing an operation for obtaining correction data used for adjusting a deviation of a document at a document reading position in the digital copying machine of FIG.

FIG. 6 is an explanatory diagram showing a format original used for adjustment when an image of an original conveyed by RDF is read by a scanner unit.

FIG. 7 is an explanatory diagram showing a format original used for adjustment when the image of the original placed on the original placing table is read by the scanner unit.

8 is an explanatory diagram showing a comparison between position data of a center reference line in a storage area of the memory of FIG. 4 and position data of a reference line of a read format document.

[Explanation of symbols]

 10 Digital copying machine 11 Scanner section 12 Laser printer section 15 RDF 61 Image data input section 62 Image data processing section 63 Image data output section 65 CPU 71, 72 Format original

Claims (1)

Claim: What is claimed is: 1. An original reading unit that reads an image of an original, data representing a position of an image of an adjustment original read by the original reading unit, and a difference between predetermined position data. It is provided with a correction means for correcting data representing a position of an image of a document read by the document reading means, and an image forming means for forming a corrected image of data representing the position by the correction means on a sheet. Image forming apparatus.