JPH08167996A - Image forming device and method - Google Patents

Abstract

PURPOSE: To provide an image forming device and its method capable of outputting a fine image by eliminating ununiformity of the image (especially thin lines) caused by resolution conversion by application of processing for uniformity. CONSTITUTION: A pattern matching section 903 applies pattern matching to 3×3 picture elements subject to resolution conversion and extracted by FIFOs 901, 902 to correct the image to eliminate ununiformity of the image (especially thin lines) thereby providing an output of a fine image.

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 and method for performing correction processing on an image whose resolution has been converted.

[0002]

2. Description of the Related Art At present, so-called systemization is in progress, such as adding functions of a printer and a facsimile to a copying machine, by combining existing separately existing ones into one.

However, since they are originally created separately, they have different resolutions and gradations. For example, a copying machine has 400 dpi · 256 gradations, and a printer has 300 dpi · 2 gradations. Therefore, if the copier is used as a printer,
It is necessary to convert the resolution of an image expanded with dpi · binary into 400 dpi · 256 and output.

[0004]

Therefore, thin lines originally having the same line width are output unevenly.
The image was distorted. This will be described with a specific example. As described above, the printer image of 300 dpi / binary is 40
When outputting with a 0 dpi · 256 value digital copying machine, a resolution conversion means from 300 dpi · 2 value to 400 dpi · 256 value is required.

There is a linear interpolation as a general resolution conversion method. As shown in FIG. 10, the value of the pixel to be converted is obtained from the ratio of the value of the surrounding original image and its distance. When the conversion from 300 dpi to 400 dpi is performed by this method, as shown in FIG. 11, even if the original value is the same, the phase difference between the original pixel and the converted pixel results in a plurality of different values. Further, due to the characteristics of the electrophotographic process, the density of pixels having a value less than 80H is not guaranteed. Therefore, the combination of the images shown in FIG. 11 causes different generation of images. That is, as shown in FIG. 12, in a comparatively thick portion of an image, it is not so noticeable, but in a thin line of 1 dot or 2 dots, there is a problem that the nonuniformity of the thickness becomes noticeable.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to output a beautiful image by eliminating the unevenness of the image (particularly fine lines) caused by the resolution conversion by performing the uniformization process. It is an object to provide an apparatus and method.

[0007]

[Means for Solving the Problems] and

In order to achieve the above object, the image forming apparatus of the present invention has the following structure.

That is, a resolution conversion means for converting the resolution of the image, a correction means for correcting the unevenness of the image caused by the resolution conversion means, and an image forming means for forming the image corrected by the correction means. Prepare

In such a configuration, an operation is performed so as to correct nonuniformity of an image (particularly, a thin line) which occurs when the resolution of the image is converted.

In order to achieve the above object, the image forming method according to the present invention has the following steps.

That is, a resolution conversion step of converting the resolution of the image, a correction step of correcting the unevenness of the image caused in the resolution conversion step, and an image forming step of forming the image corrected in the correction step. Have.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the arrangement of an image forming system according to this embodiment. In the figure, 1 is an image input device that reads a document and converts it into image data (hereinafter referred to as a reader unit), 2 has a plurality of recording paper cassettes, and image data is visualized on the recording paper by a print command. An image output device (hereinafter, referred to as a printer unit) 3 for outputting as an external device is an external device electrically connected to the reader unit 1 and has various functions. The external device 3 includes a fax unit 4, a computer interface unit 7 for connecting to an external computer, a formatter unit 8 for converting information from the computer into a visible image, a core unit 10 for controlling the above functions, and the like. Is equipped with.

The functions of the respective parts of the external device 3 will be described in detail below.

<Description of Reader Unit 1> FIG. 2 shows the reader unit 1.
3 is a cross-sectional view showing the structure of the printer unit 2 and its configuration and operation will be described below.

The originals stacked on the original feeding device 101 are sequentially conveyed one by one onto the original table glass surface 102. When the original is conveyed to a predetermined position on the glass surface 102,
The lamp 103 of the scanner unit is turned on, and the scanner unit 104 moves to illuminate the document. The reflected light of the document is input to a CCD image sensor unit 109 (hereinafter referred to as CCD) via mirrors 105, 106 and 107 and a lens 108.

Now, the configuration and operation of the circuit for signal-processing the image data input to the CCD 109 will be described below with reference to FIG.

The reflected light of the document applied to the CCD 109 is first photoelectrically converted into electric signals of R (red), G (green) and B (blue). C
The color information from the CD 109 is transferred to the next amplifier 110R,
The signals are amplified by 110G and 110B according to the input signal level of the A / D converter 111. The output signal from the A / D converter 111 is input to the shading circuit 112, where uneven light distribution of the lamp 103 and uneven sensitivity of the CCD are corrected. The signal from the shading circuit 112 is Y
The signals are input to the signal generation / color detection circuit 113 and the external I / F switching circuit 119, respectively.

Here, the Y signal generation / color detection circuit 113
Calculates the signal from the shading circuit 112 by the following equation to obtain a Y signal.

Y-0.3R + 0.6G + 0.1B Further, there is provided a color detection circuit for separating each of the R, G and B signals into seven colors and outputting the signal for each color. The output signal from the Y signal generation / color detection circuit 113 is input to the scaling / repeat circuit 114. Scaling in the sub-scanning direction is performed according to the scanning speed of the scanner unit 104, and scaling in the main scanning direction is performed by the scaling / repeat circuit 114. Further, the scaling / repeat circuit 114 can output a plurality of identical images. The contour / edge emphasis circuit 115
Edge emphasis and contour information are obtained by emphasizing high frequency components of the signal from the scaling / repeat circuit 114. The signal from the contour / edge emphasis circuit 115 is input to the marker area determination / contour generation circuit 116 and the patterning / thickening / masking / trimming circuit 117.

Marker area determination / contour generation circuit 116
Reads a portion of a document written with a marker pen of a specified color, generates contour information of the marker, and the next patterning / thickening / masking / trimming circuit 117 thickens or masks the contour information. Trimming.
Further, patterning is performed by the color detection signal from the Y signal generation / color detection circuit 113.

An output signal from the patterning / thickening / masking / trimming circuit 117 is input to a laser driver circuit 118, and various processed signals are converted into signals for driving a laser. Laser driver circuit 11
The output signal of 8 is input to the printer unit 2 and image formation is performed as a visible image.

Next, the external I / F switching circuit 119 for interfacing with the external device 3 will be described.

When the image information from the reader unit 1 is output to the external device 3, the external I / F switching circuit 119 outputs the image information from the patterning / thickening / masking / trimming circuit 117 to the connector 120. When the image information is input to the reader unit 1 from the external device 3, the external switching circuit 119 inputs the image information from the connector 120 to the Y signal generation / color detection circuit 113.

The above-mentioned image processing is performed according to an instruction from the CPU 122, and the area signal generating circuit 121 generates various timing signals necessary for the above-mentioned image processing according to the value set by the CPU 122. Further CPU12
Communication with the external device 3 is performed by using the communication function built in 2. The SUB / CPU 123 controls the operation unit 124 and also communicates with the external device 3 by using the communication function built in the SUB / CPU 123.

<Description of Printer Unit 2> Referring back to FIG. 2, the configuration and operation of the printer unit 2 will be described below.

First, the image signal input to the printer unit 2 is converted into an optical signal modulated by the exposure control unit 201, and the photoconductor 202 is irradiated with the converted optical signal. Photosensitive member 202 by irradiation light
The latent image formed above is developed by the developing device 203.
Next, the transfer paper is conveyed from the transfer history stacking units 204 and 205 at the same timing as the front end of the developing unit 203, and the transfer unit 2
At 06, the developed image is transferred. The transferred image is fixed on the transfer paper by the fixing unit 207, and then the paper discharge unit 2
It is discharged to outside the device from 08. The transfer paper output from the paper discharge unit 208 is discharged to each bin when the sort function is working in the sorter 220, or to the highest bin of the sorter when the sort function is not working. .

Further, a method of outputting images to be sequentially read on both sides of one output sheet will be described.

After the output sheet fixed by the fixing section 207 is once conveyed to the sheet discharge section 208, the conveying direction of the sheet is reversed,
The sheet is conveyed to the re-transferred transfer sheet stacking section 210 via the conveyance direction switching member 209. When the next original is prepared, the original image is read in the same manner as the above process, but the transfer paper is fed from the re-transferred transfer paper stacking section 210, so that the surface of the same output paper, Two document images can be output on the back side.

<Description of External Device 3> As shown in FIG.
The external device 3 is connected to the reader unit 1 by a cable, and the core unit 10 in the external device 3 controls signals and functions. In the external device 3, a fax unit 4 for sending and receiving a fax, a formatter unit 8 for developing code information from a computer into image information, a computer interface unit 7 for controlling an interface with a computer, and the above-mentioned functions are controlled. It consists of the core part 10.

<Description of Core Unit 10> FIG. 4 is a block diagram showing the detailed structure of the core unit 10 described above.

The connector 1001 of the core unit 10 is connected to the connector 120 of the reader unit 1 by a cable. The connector 1001 contains four types of signals, and the signal 1057 is an 8-bit multivalued video signal. A signal 1055 is a control signal for controlling a video signal, a signal 1051 is a signal for communicating with the CPU 122 in the reader unit 1, and a signal 1052 is an S signal in the reader unit 1.
This is a signal for communicating with the UB / CPU 123. Signal 10
51 and the signal 1052 are subjected to communication protocol processing by the communication IC 1002, and the CPU
The communication information is transmitted to 1003. And signal 1057
Is a bidirectional video signal line, which allows the core unit 10 to receive information from the reader unit 1 and output the information from the core unit 10 to the reader unit 1.

The signal 1057 is sent to the buffer 1010.
Where the bidirectional signal to the unidirectional signal 105
It is separated into 8,1070. The signal 1058 is the reader unit 1
8-bit multi-valued video signal from LUT1 of the next stage
011 is input. In the LUT 1011, the reader unit 1
The image information from is converted into a desired value by a look-up table.

Output signal 1059 from LUT 1011
Is input to the binarization circuit 1012 or the selector 1013. The binarization circuit 1012 has a simple binarization function for binarizing a multi-valued signal 1059 at a fixed slice level, and a binarization by a variable slice level in which the slice level fluctuates from the values of pixels around the pixel of interest. It has a function and a binarization function by the error diffusion method. Binary information is "0"
When it is 00H, it is converted to a multi-valued signal of FFH when it is "1",
It is input to the selector 1013 in the next stage.

The selector 1013 selects the signal from the LUT 1011 or the output signal of the binarization circuit 1012. The output signal 1060 from the selector 1013 is input to the selector 1014. The selector 1014 receives the output video signals from the fax unit 4, the computer interface unit 7, and the formatter unit 8 from the connector 100, respectively.
The signal 1064 input to the core unit 10 via the output signals 1060 and 1060 of the selector 1013.
And are selected by the instruction of the CPU 1003. The output signal 1061 of the selector 1014 is input to the rotation circuit 1015 or the selector 1016.

The rotation circuit 1015 has a function of rotating the input image signal by +90 degrees, -90 degrees, and +180 degrees. The rotation circuit 1015 converts the information output from the reader unit 1 into a binary signal by the binarization circuit 1012, and then stores it in the rotation circuit 1015 as information from the reader unit 1. Next, the rotation circuit 10 is instructed by the CPU 1003.
Reference numeral 15 rotates and reads the stored information. Selector 1
Reference numeral 016 selects either the output signal 1062 of the rotating circuit 1015 or the input signal 1061 of the rotating circuit 1015, and the connector 10 for the fax unit 4 as the signal 1063.
05, connector 10 to the computer interface
07, and outputs to the connector 1008 of the formatter unit 8 and the selector 1017.

The signal 1063 is a synchronous 8-bit unidirectional video bus for transferring image information from the core unit 10 to the fax unit 4, computer interface unit 7 and formatter unit 8. Also, the signal 1064 is the fax unit 4,
It is a synchronous 8-bit unidirectional video bus for transferring image information from the computer interface unit 7 and the formatter unit 8. The video control circuit 1 controls the synchronous bus of the signals 1063 and 1064.
004, and control is performed by the output signal 1056 from the video control circuit 1004. Other signals 1054 are connected to the connectors 1005 to 1008, respectively. The signal 1054 is a bidirectional 16-bit CPU bus, and asynchronously exchanges data commands. In order to transfer information to and from the fax unit 4, the computer interface unit 7, the formatter unit 8 and the core unit 10, these two video buses 1063 and 1064 and the CP are connected.
This is possible with the U bus 1054.

A signal 1064 from the fax unit 4, computer interface unit 7 and formatter unit 8 is also provided.
Is input to the selectors 1014 and 1017. This selector 1014 is used by the CPU 10 as described above.
Signal 1064 to the rotation circuit 101 of the next stage
Enter in 5. On the other hand, the selector 1017 outputs the signal 106
3 and signal 1064 are selected by the instruction of the CPU 1003. The output signal 1065 of the selector 1017 is input to the pattern matching 1018 and the selector 1019 via the expansion circuit 1025. Pattern matching 101
Reference numeral 8 performs pattern matching of the input signal 1065 with a predetermined pattern, and when the patterns match, outputs a predetermined multi-valued signal to the signal line 1066. If they do not match in the pattern matching, the input signal 1065 is output as the signal 1066.

The selector 1019 selects the signal 1065 and the signal 1066 according to an instruction from the CPU 1003. The output signal 1067 of the selector 1019 is the LUT 10 of the next stage.
It is input to 20. The LUT 1020 converts the input signal 1067 according to the characteristics of the printer when outputting the image information to the printer unit 2. Selector 1021 is L
The output signal 1068 and the signal 1065 of the UT 1020 are C
It is selected by the instruction of the PU 1003. Selector 1021
The output signal of is input to the scaling circuit 1022 at the next stage.
The scaling circuit 1022 can set scaling rates independently in the X and Y directions according to an instruction from the CPU 1003. The scaling method is a first-order linear interpolation method.

The output signal 1070 of the scaling circuit 1022 is
It is input to the equalization processing unit 1023. Uniformization processing unit 10
23 will be described later.

The selector 1024 outputs the output signal 1070 of the scaling circuit 1022 and the output signal 10 of the equalization circuit 1023.
71 is selected by the instruction of the CPU 1003. The output of the selector 1024 is input to the buffer 1010.
The signal 1070 input to this buffer 1010 is C
In response to an instruction from the PU 1003, it becomes a bidirectional signal 1057 and is sent to the printer unit 2 via the connector 1001 and printed out.

The signal flow between the core section 10 and each section will be described below.

[Operation of Core Unit 10 Based on Information of Fax Unit 4] First, the case of outputting information to the fax unit 4 will be described. The CPU 1003 communicates with the CPU 122 of the reader unit 1 via the communication IC 1002 and issues a document scan command. The reader unit 1 outputs image information to the connector 120 when the scanner unit 104 scans a document according to this command. The reader unit 1 and the external device 3 are connected by a cable, and information from the reader unit 1 is input to the connector 1001 of the core unit 10. Further, the image information input to the connector 1001 is multi-valued 8
It is input to the buffer 1010 as a bit signal 1057. This buffer circuit 1010 converts the bidirectional signal 1057 into a unidirectional signal 1058 according to the instruction of the CPU
Input to T1011. The reader unit 1 in the LUT 1011
The image information from is converted into a desired value using a look-up table.

For example, it is possible to remove the background of the original. The output signal 1059 of the LUT 1011 is input to the binarization circuit 1012 at the next stage. Binarization circuit 1012
Converts the 8-bit multilevel signal 1059 into a binary signal.
The binarization circuit 1012 converts the binarized signal to 00H when it is "0" and FFH when it is "1" into two multilevel signals. The output signal of the binarization circuit 1012 is the selector 101.
3, the selector 1014 is input to the rotation circuit 1015 or the selector 1016. The output signal 1062 of the rotation circuit 1015 is also input to the selector 1016, and the selector 10
16 selects either signal 1061 or signal 1062. The signal is selected by the CPU 1003 by the CPU bus 10.
It is determined by communicating with the fax unit 4 via 54. The output signal 1063 from the selector 1016 is sent to the fax unit 4 via the connector 1005.

Next, the case of receiving information from the fax unit 4 will be described.

The image information from the fax unit 4 is transmitted as a signal 1064 via the connector 1005. The signal 1064 is input to the selector 1014 and the selector 1017. When the image at the time of fax reception is rotated and output to the printer unit 2 according to the instruction of the CPU 1003, the signal 1064 input to the selector 1014 is output to the rotation circuit 1.
Rotation processing is performed at 015. The output signal 1062 from the rotation circuit 1015 is input to the pattern matching 1018 via the selector 1016, the selector 1017, and the expansion circuit 1025.

When the image at the time of fax reception is output as it is to the printer unit 2 according to the instruction of the CPU 1003,
The signal 1064 input to the selector 1017 expands the circuit 1
It is input to 025 and is simply enlarged to double, and then input to the pattern matching 1018. The pattern matching 1018 has a function of smoothing rattling of an image when received by fax. The reason why the pattern matching is performed after the fax received image is doubled is to improve the smoothing function.

The pattern-matched signal is input to the LUT 1020 via the selector 1019. LU
In T1020, the CPU 1003 can change the table of the LUT 1020 in order to output the received fax image to the printer unit 2 at a desired density. LUT
The output signal 1068 of 1020 is input to the scaling circuit 1022 via the selector 1021. Scaling circuit 1022
Performs a scaling process on an 8-bit multivalue having two values (00H, FFH) by a linear interpolation method of the first order. Variable magnification circuit 1
The 8-bit multi-valued signal having many values from 022 is input to the equalization circuit 1023. Equalizing circuit 1023
Has a function of correcting non-uniformity of the image width that occurs when the resolution of the fax is scaled to the resolution of the printer unit 2. Details of the equalizing circuit 1023 will be described later. The output of the equalization circuit 1023 is sent to the reader unit 1 via the buffer 1010 and the connector 1001.

The reader unit 1 sends the above-mentioned signals to the connector 12
It is input to the external I / F switching circuit 119 via 0.
The external I / F switching circuit 119 inputs the signal from the fax unit 4 to the Y signal generation / color detection circuit 113. The output signal from the Y signal generation / color detection circuit 113 is processed as described above and then output to the printer unit 2 to form an image on an output sheet.

[Operation of Core Unit 10 Based on Information of Computer Interface Unit 7] The computer interface unit 7 interfaces with a computer connected to the external device 3. The computer interface unit 7 has a plurality of interfaces for communicating with SCSI, RS232C, and Centronics. The computer interface unit 7 has the above-described three types of interfaces, and information from each interface is sent to the CPU 1003 via the connector 1007. CP
The U1003 performs various controls based on the sent contents.

[Core part 1 based on information from the formatter part 8]
0 operation] The formatter unit 8 is the computer
It has a function of expanding command data such as a document file sent from the interface unit 7 into image data. When the CPU 1003 determines that the information sent from the computer interface unit 7 is the information regarding the formatter unit 8, the CPU 1003 transfers the information to the formatter unit 8 via the connector 1008. The formatter unit 8 develops in the memory from the transferred information as a meaningful image such as a character or a figure.

Next, a procedure for receiving information from the formatter unit 8 and forming an image on an output sheet will be described. The image information from the formatter unit 8 is the connector 100.
8 is transmitted as a multilevel signal 1064 having two values (00H, FFH). The signal 1064 is input to the selector 1014 and the selector 1017. CPU1
The selectors 1014 and 1017 are controlled by the instruction of 003. The subsequent processing is the same as the case of the above-mentioned fax, and therefore the description thereof is omitted.

(Description of Fax Unit 4) FIG. 5 is a block diagram showing the detailed arrangement of the fax unit 4.

The fax unit 4 is connected to the core unit 10 by the connector 400 and exchanges various signals. Core part 10
When storing the binary information from the memory A405 to the memory D408, the signal 453 from the connector 400 is input to the memory controller 404, and the memory A405, the memory B406, and the memory C407 are controlled by the memory controller 404. , Memory D 408, or a cascade connection of two sets of memories.

The memory controller 404 is the CPU 41.
2 is a mode for exchanging data with the memory A 405, the memory B 406, the memory C 407, the memory D 408 and the CPU bus 462, and a mode for exchanging data with the CODEC bus 463 of the CODEC 411 having an encoding / decoding function. Memory A405, memory B
406, memory C407, memory D408 contents DM
A mode in which data is exchanged with the bus 454 from the scaling circuit 403 under the control of the A controller 402, and binary video input data 454 is stored in any of the memories A405 to D408 under the control of the timing generation circuit 409. Mode and memory A405 to memory D40
It has five functions of a mode in which the memory content is read out from any one of 8 and output as a signal 452.

Each of the memory A 405, the memory B 406, the memory C 407, and the memory D 408 has a capacity of 2 Mbytes and stores an image of A4 size at a resolution of 400 dpi. The timing generation circuit 409 is the connector 4
00, and the control signal (HSYN
C, HEN, VSYNC, VEN) to generate signals to achieve the following two functions. The first is a function of storing the image signal from the core unit 10 in any one of the memories A405 to D408 or two memories, and the second is a function of storing the memories A405 to D4.
The image signal is read from any one of
2 is a function of transmitting. Dual port memory 4
10 is the CPU 1 of the core unit 10 via the connector 400.
003 and the CPU 412 of the fax unit 4. Each CPU exchanges commands via the dual port memory 410.

The SCSI controller 413 interfaces with the hard disk connected to the fax unit 4 of FIG. Stores the data when sending a fax or receiving a fax. The CODEC 411 is a memory A4
05 to the memory D 408, the image information stored in any of the memories A 405 to D
Any one of 408 is stored as encoded information. Also,
After the encoded information stored in the memories A405 to D408 is read and encoded by a desired method of the MH, MR, and MMR methods, the memory A405 to the memory D4.
The data is stored in any of No. 08 as decoding information, that is, image information. The MODEM 414 has a function of modulating the coded information from the hard disk connected to the CODEC 411 or the SCSI controller 413 in order to transfer the coded information to the telephone line, and demodulates the information sent from the NCU 415 to convert it into coded information. CODEC 411 or SC
It has a function of transferring encoded information to a hard disk connected to the SI controller 413. NCU41
Reference numeral 5 exchanges information with a switching system installed directly at a telephone station or the like, which is directly connected to a telephone line by a predetermined procedure.

Next, the operation of fax transmission in this embodiment will be described. First, the binary image signal from the reader unit 1 is input via the connector 400 and reaches the memory controller 404 as a signal 453. The signal 453 is stored in the memory A 405 by the memory controller 404. The timing stored in the memory A 405 is generated by the timing generation circuit 409 according to the timing signal 459 from the reader unit 1. The CPU 412 replaces the memory A 405 and the memory B 406 of the memory controller 404 with C
Connect to the bus 463 of the ODEC 411. CODEC4
11 reads the image information from the memory A405,
Encoding is performed by the MR method and the encoded information is stored in the memory B40.
Write to 6. CODEC for A4 size image information
Once encoded by 411, CPU 412 connects memory B 406 of memory controller 404 to CPU bus 462. The CPU 412 stores the encoded information in the memory B4.
The data is sequentially read from 06 and transferred to the MODEM 414. M
The ODEM 414 modulates the encoded information, and the NCU
Send fax information over the telephone line via.

Next, the fax reception operation will be described. First, the information sent from the telephone line is input to the NCU 415 via the connector 416, and is connected to the fax unit 4 by the NUC 415 in a predetermined procedure. The information from NCU 415 enters MODEM 414 and is demodulated. CPU412
Stores information from the MODEM 414 in the memory C407 via the CPU bus 462. When the information of one screen is stored in the memory C407, the CPU 412 connects the memory C407 to the CODEC 411 by controlling the memory controller 404. The CODEC 411 sequentially reads the encoded information in the memory C407 and decodes it, that is, stores it in the memory D408 as image information. CP
The U412 communicates with the CPU 1003 of the core unit 10 via the dual port memory 410, and the memory D408
From the core unit 10 to the printer unit 2 to print out an image. Here, when the setting is completed, the CPU 412 activates the timing generation circuit 409 and outputs a predetermined timing signal 460 to the memory controller 404. The memory controller 404 reads the image information from the memory D408 in synchronization with the timing signal 460 from the timing generation circuit 409,
It is transmitted as a signal 452 and output from the connector 400. The description up to the output from the connector 400 to the printer unit 2 is omitted because it has been described in the core unit 10.

(Description of Computer Interface Unit 7) Next, the computer interface unit 7 will be described with reference to FIG.

Connector A700 and connector B701
Is a connector for SCSI interface. The connector C702 is a Centronics interface connector. The connector D703 is an RS2322C interface connector. The connector E707 is a connector for connecting to the core unit 10.

The SCSI interface has two connectors (connector A700 and connector B701). When connecting a device having a plurality of SCSI interfaces, the connector A700 and connector B701 are used for cascade connection.

The external device 3 and the computer are in a one-to-one correspondence.
In the case of connection with, the connector A700 and the computer are connected with a cable and the connector B701 is connected with a terminator, or the connector B701 and the computer are connected with a cable and the terminator is connected with the connector A700. Information input from the connector A 700 or the connector B 701 is sent to the SCSI.
It is input to the I / F-A 704 or the SCSI I / F-B 708. In addition, SCSI I / F-A704 or SCS
The I / I-F-B 708 outputs a signal 754 to the connector 707E after performing a procedure according to the SCSI protocol.

This connector E707 is C of the core portion 10.
CP of core unit 10 connected to PU bus 1054
The U1003 is connected to the SCSI / I / from the CPU bus 1054.
F connector (connector A700, connector B701)
Receive the information entered in. CPU 10 of core unit 10
Data from 03 is SCSI connector (connector A7
00, connector B701), the procedure is the reverse of that described above.

The Centronics interface is connected to the connector C702, and the signal 752 is input to the Centronics I / F 705. This Centronics I
/ F705 receives the data according to the procedure of the determined protocol, and outputs it as the signal 754 to the connector E707. The connector E707 is the CPU bus 1 of the core unit 10.
054 and is connected to the CPU 1003 of the core unit 10.
Receives from the CPU bus 1054 the information input to the Centronics I / F connector (connector C702).

RS232C interface is connector D
The signal 753 is connected to the RS232C.
It is input to the I / F 706. This RS232C I / F
706 receives the data according to the procedure of the determined protocol, and outputs it as the signal 754 to the connector E707. The connector E707 is the CPU bus 105 of the core unit 10.
4 and the CPU 1003 of the core unit 10 is C
Information input to the RS232C I / F connector (connector D703) is received from the PU bus 1054.
The data from the CPU 1003 of the core unit 10 is RS232
When outputting to the C / I / F connector (connector D703), the procedure is the reverse of that described above.

(Description of Formatter Unit 8) FIG. 7 is a block diagram showing the configuration of the formatter unit 8. The configuration and operation of the formatter unit 8 will be described below with reference to the drawings.

The information from the computer interface unit 7 described above is discriminated by the core unit 10. If the information is related to the formatter unit 8, the CPU of the core unit 10
1003 transfers information sent from the computer to the dual port memory 803 via the connector 1008 of the core unit 10 and the connector 800 of the formatter unit 9. The CPU 809 of the formatter unit 8 receives the code data sent via the dual port memory 803. The CPU 809 sequentially expands this code data into image data, and transfers the image data to the memory A 806 or the memory B 807 via the memory controller 808. The memory A 806 and the memory B 807 each have a capacity of 1 MB, and one memory (memory A 80
6 or memory B807) and A4 at a resolution of 300 dpi
Paper sizes up to If the resolution of 300 dpi corresponds to A3 paper, the memory A80
6 and the memory B807 are connected in cascade to develop image data.

The memory control described above is performed by the memory controller 808 according to an instruction from the CPU 809. Further, when it is necessary to rotate a character or a graphic when expanding the image data, the image data is rotated by the rotation circuit 804 and then transferred to the memory A 806 or the memory B 807. When the expansion of the image data in the memory A806 or the memory B807 is completed, the CPU 809 controls the memory controller 808 to connect the data bus 858 of the memory A806 or the data bus 859 of the memory B807 to the output of the memory controller 808. Next CPU8
09 is the core unit 1 via the dual port memory 803.
The CPU 1003 communicates with the CPU 1003 of 0 to set the mode in which the image information is output from the memory A 806 or the memory B 807. The CPU 1003 of the core unit 10 sets the print output mode in the CPU 122 using the communication function built in the CPU 122 of the reader unit 1 via the communication circuit 1002 in the core unit 10.

Here, when the print output mode is set, the CPU 1003 of the core unit 10 causes the connector 1008,
Also, the timing generation circuit 802 is activated via the connector 800 of the formatter unit 8. The timing generation circuit 803 generates a timing signal for reading image information from the memory A 806 or the memory B 807 to the memory controller 808 according to the signal from the core unit 10. The image information from the memory A 806 or the memory B 807 is input to the memory controller 808 as a signal 858. The output image information from the memory controller 808 is sent as a signal 851 via the connector 800 to the core unit 1.
Is transferred to 0. The output from the core unit 10 to the printer unit 2 has been described in the core unit 10 and will not be described.

(Description of Uniformization Processing Unit 1023) Next, the configuration and operation of the aforementioned uniformization processing unit 1023 will be described in detail.

Here, when an image from the formatter unit 8 of 300 dpi is output to the printer unit 2 of 400 dpi, that is, 600 dpi in the scaling circuit 1022.
The case where the image is reduced to 400 dpi will be described. In the case of conversion of other resolutions, only the parameters are different and the method is the same.

FIG. 8 is a diagram showing the structure and pattern of the equalization processing unit 1023. As shown in the figure, the equalization processing unit 1023 uses the input pixels and the FIFOs 901 and 90.
The pattern matching unit 903 performs 3 × 3 pattern matching on the pixels delayed by 2.

When a 600 dpi image that has been simply doubled by the enlargement circuit 1025 is reduced to 400 dpi, 3
The FFH of the 00 dpi image is (40H, FFH), (FF
H, 40H) and (BFH, BFH). At this time, even with the same 1-dot line (40H, FFH),
When the phase difference is (FFH, 40H) and (BFH, BF
In the case of the phase difference of H), the output image of the printer unit 2 is more finely output in the former case. Therefore, matching with the pattern shown in FIG. 8 is performed, and if there is a match, the value of the pixel of interest is replaced with AFH. Here, AFH is (40
H, FFH) is a value obtained empirically so as to be the same as the output width of one dot line of the phase difference of (H, FFH). Further, this pattern corresponds only to the vertical line / horizontal line portion, and the processing is not performed on a fine character portion or the like, so that this processing is prevented from being omitted at unnecessary points.

FIG. 9 is a diagram showing a modification of the homogenization processing section. At the same time as the image information, the phase difference between the input image and the output image at the time of scaling is also input to the equalization processing unit, and when the input phase difference is a specific one (such as outputting 40H). Only the phase difference) is subjected to pattern matching by the pattern matching unit 904, and if there is a match, the pixel value is A
Replace with FH.

By giving the phase difference in this way,
The number of pattern matching comparisons can be reduced.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. It goes without saying that the present invention can also be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0078]

As described above, according to the present invention,
By performing the homogenization process, it is possible to eliminate the non-uniformity of the image (particularly, the fine line) caused by the resolution conversion and output a beautiful image.

[0079]

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of an image forming apparatus in this embodiment.

FIG. 2 is a cross-sectional view showing structures of a reader unit 1 and a printer unit 2.

FIG. 3 is a block diagram showing a configuration of a signal processing unit in the reader unit 2.

FIG. 4 is a block diagram showing a configuration of a core unit 10.

FIG. 5 is a block diagram showing a configuration of a fax unit 4.

FIG. 6 is a block diagram showing a configuration of a computer interface unit 7.

FIG. 7 is a block diagram showing a configuration of a formatter unit 8.

FIG. 8 is a diagram showing a configuration and a pattern of a homogenization processing unit in the present embodiment.

FIG. 9 is a diagram showing a configuration and a pattern of a homogenization processing unit in a modified example.

FIG. 10 is a diagram for explaining primary interpolation.

FIG. 11 is a diagram illustrating an example of linear interpolation.

FIG. 12 is a diagram showing an example of an output image.

[Explanation of symbols]

 1 reader unit 2 printer unit 3 external device 4 fax unit 7 computer interface unit 8 formatter unit 10 core unit

Claims (12)

[Claims] 1. A resolution conversion means for converting the resolution of an image, a correction means for correcting unevenness of the image caused by the resolution conversion means, and an image forming means for forming an image corrected by the correction means. An image forming apparatus comprising: 2. The image forming apparatus according to claim 1, wherein the correction unit corrects by pattern matching. 3. The image forming apparatus according to claim 2, wherein a 3 × 3 matrix is used as the pattern matching. 4. The image forming apparatus according to claim 3, wherein each row or each column has the same value for the pattern matching. 5. The correction unit corrects an image based on phase difference information at the time of resolution conversion.
The image forming apparatus described. 6. The image forming apparatus according to claim 2, wherein the correction unit performs pattern matching based on phase difference information at the time of resolution conversion. 7. The image forming apparatus according to claim 1, further comprising interface means for communicating with a computer to exchange images with the computer. 8. An interface unit with a computer and an image output unit for outputting an image are further provided, and resolution conversion and correction are performed on an image input via the interface unit, and the image output unit outputs the image. The image forming apparatus according to claim 1, wherein the image is output. 9. A conversion means for converting code data into an image is further provided, wherein the conversion means converts the code data input through the interface means into image data, and the image output means outputs the image. The image forming apparatus according to claim 5, wherein 10. An image reading unit for reading an image, and a communication unit for communicating with a facsimile apparatus, wherein resolution conversion and correction are performed on the image read by the image reading unit, and the communication unit is provided. The image forming apparatus according to claim 1, wherein the image is transmitted via the image forming apparatus. 11. A communication device for communicating with a facsimile device, and an image output device for outputting an image, further comprising: resolution conversion and correction for an image received from the communication device; The image forming apparatus according to claim 1, wherein the image is output further. 12. A resolution conversion step of converting the resolution of an image, a correction step of correcting unevenness of the image caused in the resolution conversion step, and an image forming step of forming the image corrected in the correction step. An image forming method having: