JP3496946B2 - Color image forming equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus such as a digital color copying machine, a color facsimile and a color printer.

[0002]

2. Description of the Related Art In recent years, colorization of images has progressed, and in parallel with this, the need for colorization of copying machines has increased. The request for a hard copy of a color image is not only a document original but also DTP (desk top publishing), CG.
Images created using a computer such as (computer graphics), images captured by video cameras, images stored in optical files, images sent via communication lines such as facsimiles, etc. A wide variety.

On the other hand, systematization and combination of OA devices are being promoted from the viewpoint of space saving and efficient use of resources. Therefore, the copying machine can be used as a printer or a facsimile by considering not only the copying function but also an I / F (interface) as an appropriate external signal. By the way, as a color image forming apparatus for making a hard copy, a silver salt photographic method, an electrophotographic method, a fusion type thermal transfer method, a sublimation type thermal transfer method, an inkjet method, etc. have been put into practical use. The conventional laser printer is used when high speed, high image quality and plain paper recording are required.

In the case of the electrophotographic method among the respective methods, it is difficult to change or stop the speed of the image forming process on the way, so that the input of image data follows the speed of the output system (image forming process speed). In a color image forming apparatus that cannot be guaranteed, the normal frame memory is used, and the image data to be output is temporarily stored in the frame memory, and then read and output according to the image forming process speed.

In such a color image forming apparatus, three colors of Y (yellow), M (magenta), C (cyan) or K are used in order to form a color image at high speed.
It has an image forming unit corresponding to each of the four color materials including (black), and images are formed on the photoconductor in parallel with three or four colors, and each color on the recording paper (transfer material). The materials are transferred and overlapped.

FIG. 26 shows a color image forming apparatus as described above.
The digital color copying machine shown in FIG. 1 will be described as a more specific example. In this digital color copying machine, internal input data input from a built-in image reading unit (scanner) 1 is subjected to predetermined image processing by two image processors 2 and 3 constituting an image processing unit, and then,
A copy mode for sending an image to the output system 5 through the delay memory 4 and external input data input from the external device 6 through the external interface (I / F) 7 are temporarily stored in the RGB frame memory 8 and then read out. It has a printer mode in which a predetermined image processing is performed by the processor 3 and is sent to the output system 5 through the delay memory 4 to form an image.

The selection of the mode is performed by a control unit (not shown), which instructs the multiplexer 9 to select and output the internal input data when the copy mode is selected, and the internal input when the printer mode is selected. Instruct to select and output data.

The image processor 2 is a processing circuit relating to correction of internal input data output from the image reading unit 1 and an image processing function peculiar to the copy mode, and a scaling circuit 11 for enlarging / reducing the internal input data. A processing circuit 12 that performs processing such as italicization, hollowing, and shadowing of an image, and MTF (Modulation) of internal input data.
It is composed of an RGB filter circuit 13 that performs spatial filter processing that corrects deterioration of the transfer function and removes noise.

The image processor 3 is a circuit that mainly performs processing relating to adjustment of the image quality of an output image (hard copy), and is a circuit that is commonly used regardless of internal input data or external input data. That is, for the RGB image data (RGB data), the RGBγ correction circuit 1
4, RGB data to YMCK image data (YMCK
Color correction circuit 15, UCR for converting to K data)
(Under Color Removal) circuit 16, YMCKγ correction circuit 17 for correcting the gradation characteristic of the output system 5, YMCK filter circuit 18 for adjusting the sharpness of the image, and output system 5
Gradation processing circuit 1 that performs gradation expression by using an area gradation processing method such as dither processing when a sufficient number of gradations cannot be obtained.
It is composed of 9.

[0010]

However, in the conventional color image forming apparatus as described above, in order to superpose a plurality of colors on the recording paper, the image signals of the respective colors output from the image processing unit are recorded on the recording paper. It is necessary to delay by the delay memory (delay element) by the time until the image reaches the transfer position of the image forming unit corresponding to each color, and to shift the timing of writing to the photoconductor that is the image carrier. Had to use a lot of memory.

Here, the memory capacity when a DRAM is used as the delay memory will be described with reference to FIG. 27. The drum interval between the photosensitive drums 21a to 21d is L (mm), and the output dot density is M. (Dot / m
m), the number of bits per output dot 1 color is N (bit
/ Dot) and the width of the recording paper P is W (mm), the total memory capacity S of the delay memories 22a to 22c is S = W × M × L × M × N + W × M × 2L × M × N + W × M × 3L × M × N = W × M × 6L × M × N (bit).

For example, W = 297 mm, L = 100 m
If m, M = 16 dot / mm, and N = 8 bit / dot, then S = 297 × 16 × 6 × 100 × 16 × 8 = 364953600 (bit) = 348.0 [Mbit] (megabit), and the capacity of 4 Mbit When using DRAM, 87 pieces are required.

On the other hand, as described above, when outputting external input data, a frame memory is required, but its memory capacity T is A4 size (297 mm × 210 mm) and is R (red), G (green), B ( Assuming that the color-separated data is input in 8 bits / dot for each color, T = 297 x 16 x 210 x 16 x 8 x 3 = 383201280 (bit) = 365.4 (Mbit) and 4 Mbit DRAM 92 are required.

Therefore, in order to construct a system capable of outputting external input data, the delay memory and the frame memory are combined to form an image data memory 17
A large number of memory chips as many as 9 are required, resulting in an expensive system. The present invention has been made in view of the above problems, and an object of the present invention is to reduce the amount of memory used and realize low cost.

[0015]

In order to achieve the above object, the present invention has four image forming units, and images formed in parallel on four image carriers of the image forming units. In a color image forming apparatus for forming a color image by sequentially transferring the images onto a transfer material, the following features are provided.
To do.

A color image forming apparatus according to the present invention.
Is 1 page for RGB image data input from the outside.
Image data of 4 systems are read out in parallel from the memory for storing data for 4 minutes , and the image data of 4 systems are read out in parallel with a time difference from the 4 locations of the memory, and each of the image data is converted into a predetermined one-component data of YMCK system image data. And means for converting the YMCK image data converted by the means in parallel.
Color images are formed by sending them to each image forming unit.
It was made to let you .

A color image forming apparatus according to the present invention.
Is configured such that the interval between the transfer portions of the image carrier of each image forming unit is one third or more of the maximum length of the transfer material in the transport direction, and the RGB image data input from the outside is used. The memory for storing one page and the image data of three systems are read out in parallel from the three locations of the memory with a time difference.
Means for converting the respective image data in parallel into data of a predetermined one component of YMCK image data, and YMCK image data converted by the means.
Image in parallel to each image forming unit
It is designed to be formed .

A color image forming apparatus according to the invention of claim 3
Is an internal input means for reading a document image, an external input means for inputting color image data from the outside, a memory for storing image data, and RGB-based image data for YMCK-based
Conversion means for converting the image data of, when the image data to be stored in the image data from the internal input means該画
The image data is converted into YMCK image data by the conversion means.
Image data is stored in the memory after being converted
By using the memory, the image forming unit's image forming unit
Operates as a delay memory for the image data of YMCK system used to correct the grayed, when image data to be stored in the image data from the external input means, said memory as a frame memory of the image data of the RGB system A memory control means for operating is provided , and the memory control means is operated by the means.
Memory is used as a frame memory for RGB image data.
RGB input from external input means
After storing one page of system image data in the memory,
From 4 locations in the memory, 4 systems are arranged in parallel with a time difference.
Read out the image data and convert each image data
Image data of YMCK system in parallel for each stage
YMCK after conversion to constant 1-component data
To send the image data of the system to each image forming unit in parallel
It is designed for more color image formation.
It

A color image forming apparatus according to the present invention.
Is an internal input unit for reading a document image, an external input unit for inputting color image data from the outside, an image processing unit for performing a process including color system conversion on the input data, a memory for storing the image data, and an internal unit. The image data from the input means is input to the memory after the image processing by the image processing means, the image data from the external input means is stored in the memory, and then the image data is read from the memory. A data selecting means for selecting a data flow so that the image processing is performed by the processing means is provided .
When forming an image based on the image data input from
Stored the image data for one page in the memory.
After that, multiple locations are copied in parallel with a time difference from multiple locations in that memory.
Image data of several systems is read and each image data is displayed.
Images of different color systems in parallel by image processing means
After converting to the data of the predetermined one component of the data, after the conversion
Image data of the color system of
Color images can be formed by sending
It is a thing .

[0020]

[0021]

[0022]

[0023]

According to the color image forming apparatus of the first aspect of the present invention , RGB image data input from the outside is transmitted by one page.
After temporarily stored in over equity memory, one predetermined component of the image data of the four locations of the memory in parallel with the time difference and the image data four systems, each YMCK system in parallel the respective image data Image data, and the converted YMCK image data is converted in parallel to each image forming unit.
Since the color image is formed by sending the data to the printer, the amount of memory used can be reduced and external input data can be output at low cost.

According to the color image forming apparatus of the second aspect of the present invention, the distance between the transfer portions of the image carrier of each image forming unit is at least one-third of the maximum transfer material length in the transport direction. The RGB image data input from the outside
After once storing in the memory for one page, the image data of three systems are read out in parallel from three locations of the memory with a time difference, and each image data is concurrently processed in a predetermined one component of YMCK image data. Image data, and the converted YMCK image data is converted in parallel to each image forming unit.
Color image formation by sending it to
Memory usage is reduced and RGB image data is
It is possible to reduce the number of circuits for converting to MCK image data.

According to the color image forming apparatus according to the invention of claim 3, the image data to be stored in the case of the image data from the internal input means, the image data of YMCK system
After being converted to image data, the image data is stored in memory.
By storing the memory, the image is created by the image forming unit.
It operates as a delay memory for the image data of YMCK system used to correct the timing when the image data to be stored in the image data from the external input means,
The memory operates as a frame memory for RGB image data . Then, the memory is used to store the RGB image data.
When operating as a frame memory, use an external input
The RGB image data input from the column is stored in a memory.
Memory for 4 minutes, then set the time difference from 4 locations in the memory
Image data of 4 systems are read out in parallel and each image
In parallel with the data, the YMCK image data
YMCK system after conversion to constant 1-component data
By sending the image data of
Color image formation. Therefore , the amount of memory used can be reduced, and internal input data and external input data can be output at low cost.

According to the color image forming apparatus according to the invention of claim 4, the image data from the internal input means is input to memory after image processing by the image processing means, image data from the external input means to the memory After memorizing , from that memory
The data flow is selected so that the image processing means performs image processing on the read image data . And
Image based on image data input from external input means
When forming, one page of the image data is stored in the memory.
After memorizing the minutes, make a time difference from multiple locations in the memory
Image data of multiple systems are read in parallel and each image is read.
The data is processed in parallel by the image processing means
Converts the image data of the color system into the data of the specified one component,
The image data of the color system after the conversion is parallelly processed for each image formation.
Color image formation by sending to the unit
It Therefore , the amount of memory used can be reduced, and in the case of external input, color adjustment can be easily performed many times without receiving data again and the data can be output.

[0027]

[0028]

[0029]

[0030]

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 2 is an overall configuration diagram of an electrophotographic digital color copying machine showing an embodiment of the present invention.
The parts corresponding to those in FIG. 26 are designated by the same reference numerals.

This digital color copying machine includes an original reading unit (scanner) 1 for reading an image of an original,
A main body controller 32 including an image processor that electrically processes an image signal output from the document reading unit 1 as a digital signal, and prints according to image data of each color and various drive signals from the main body controller 32. The printer 33 is configured to perform an operation and form an image on the recording paper P.

Then, in the printer 33, 4 to be used
Photoreceptor drums 34a to 34d (which may be constituted by three colors) corresponding to each color (hereinafter, simply referred to as a photoreceptor drum 34 unless otherwise specified), and an original document on each photoreceptor drum 34. Laser light emitting devices 35a to 35d, which serve as exposure means for forming light corresponding to the image of the electrostatic latent image to form an electrostatic latent image, and developing devices 36K different for each color for visualizing the electrostatic latent image. , 36C, 36M, 36Y
And a conveyance belt device 50 that conveys the recording paper P to each of the transfer portions 37a to 37d for transferring the visible image on the photosensitive drum 34, and the recording paper P on the transfer / conveyance belt 38 of the conveyance belt device 50. A paper feeding device 39 for feeding the paper is provided.

A document pressing plate 40 is provided on the upper portion of the image reading unit 1, and the document mounting plate (contact glass) 41 is opened by opening the document pressing plate 40 upward.
The original can be fixed at the set position by setting the original on top and closing the original pressing plate 40.

When a print key (not shown) is pressed in this state, the original reading unit 1 exposes and scans the original on the original table 41 with a lamp (for example, a fluorescent lamp) 42, and the reflected light from the original is reflected by each mirror. The light enters the imaging lens 46 via 43, 44 and 45. The image light incident on the imaging lens 46 is imaged on the dichroic prism 47, and is split into, for example, light of three types of wavelengths of red R, green G, and blue B, and each wavelength corresponding to each wavelength light. Light receiver 48R (for red), 48G (for green), 4
8B (for blue) is made incident respectively.

Each light receiver (CCD) 48R, 48G, 48
B exchanges the incident light into a digital signal and outputs the signal (RGB data) to the main body control section 32, and the main body control section 32 performs necessary processing according to the signal to perform image data of each color, for example, The image data is converted into image data for recording and forming each color of black K, cyan C, magenta M, and yellow Y, and the image data is sent to the laser light emitting devices 35a to 35d of the printer 33 corresponding to each color.

Around the photosensitive drum 34a for the black color of the printer 33, the charging charger 4 is provided.
9, known portions for performing the image forming process, such as a transfer portion 37a having a transfer charger, are provided, and the surface of the photosensitive drum 34a is uniformly charged by the charging charger 49, and Is irradiated with laser light from the laser light emitting device 35a to be exposed to form a latent image of a black light image, which is developed by the developing device 36K to form a visible image.

Similarly, around the photosensitive drums 34b to 34d for the other colors of cyan, magenta, and yellow, respective parts such as the respective chargers 49 and the transfer parts 37b to 37d for executing the image forming process are provided. Each is provided.

In the paper feeding device 39, paper feeding cassettes 51A and 51b are vertically and vertically detachably attached to the side surface of the printer section 33, and the recording paper P stored therein is fed from one of the paper feeding cassettes. Paper is fed by each paper feed roller 52 provided on the upper portion on the delivery end side, and fed out by the registration rollers 53 to the conveyor belt device 50 at a predetermined timing.

The conveyor belt device 50 includes a driving roller 54, a driven roller 55, and an auxiliary roller 56 including a plurality of tension rollers (only one is shown in FIG. 2 for simplification).
An endless transfer / conveyance belt 38 is stretched between the sheet and a paper guide 58 for guiding the recording paper P fed by the registration roller 53 of the sheet feeding device 39 to the surface of the transfer / conveyance belt 38. ing.

The transfer / conveyance belt 38 is formed of a dielectric film such as polyester or a rubber material such as urethane, and is charged by a belt charger 60 provided on the surface thereof so that the recording paper P can be adsorbed. The recording paper P guided by the paper guide 58 to the belt surface is electrostatically adsorbed on the belt surface and is accurately conveyed at a predetermined conveying speed.

The recording paper P conveyed by the conveyor belt device 50 is sequentially sent to the respective photosensitive drums 34a to 14d on which a visible image is formed, and the respective transfer portions 3 are transferred.
The visible images are sequentially transferred by the transfer charger at 7a to 37d. The recording paper P to which the visible image (image) is transferred is fixed by the fixing roller 59, and is ejected by a paper ejection roller 61 to a paper ejection tray (not shown) outside the apparatus.

FIG. 3 is a block diagram of a main part of a control system of this digital color copying machine, and parts corresponding to those in FIG. 26 are designated by the same reference numerals. The system controller 65 includes an image reading unit 1, a main controller 67, and the printer 33.
Operation panel 66, output system 5, and printer control circuit 69
Control each module.

That is, the display control of the operation panel 66 and the key input processing are performed, and the image reading unit 1 and the printer 3 are operated according to the mode set by the operation panel 66.
To the main control unit 67, or to send a start signal or a scaling factor designating signal to the main control unit 67 (color conversion, masking, trimming, mirroring, etc.), or an abnormal signal from each module, operation status status The entire system is controlled by signals (wait, ready, busy, stop).

The image reading unit 1 exposes and scans an original at a scanning speed that matches a scaling ratio designated by a start signal from the system controller 65, and the original image is CCD-scanned.
It is read by a reading element such as the above and is sent to the main control unit 67 as RGB image data (RGB data).
The main controller 67 is composed of the image processors 2 and 3 shown in FIG. 26, a memory functioning as a frame memory and a delay memory, and the like.

The printer control circuit 68 includes a main controller 6
According to the YMCK image data (YMCK data) output from 7, the laser light emitting device of the output system 5 is modulated, and a transfer image is formed on the recording paper by the electrophotographic process.

FIG. 1 is a principal block diagram showing a portion of the main controller 67 relating to the present invention, and the portions corresponding to those in FIG. 26 are designated by the same reference numerals. In FIG. 1, the flow of input data is variable between the memory 74 and the image processor 3 by multiplexers (MUX) 71 to 73. That is, the order in which the image data flows to each circuit is changed according to the operation mode. Further, the memory 74 functions as a delay memory or a frame memory depending on the operation mode.

4 to 7 show the flow of image data in each operation mode. FIG. 4 shows the flow of image data in the copy mode, and the memory 74 is used as a delay memory for YMCK data. In the copy mode, image data is input to output in real time.

5 to 7 show the flow of image data in the printer mode, of which the memory 74 is shown in FIG.
Is used as a frame memory for RGB data. As a result, the RGB data input from the external device 6 through the external I / F 7 is temporarily stored in the memory 74 for one page. After that, the RGB data is read from the memory 74 in synchronization with the pixel sync signal for output, converted into YMCK data by the image processor 3, and output from the output system 5.
And the image is output by the printer 33.

A feature of this configuration is that the data once transferred to the memory 74 functioning as an RGB frame memory can be saved without being lost even if it is output by the printer 33. Therefore, by changing the parameters of the image processor 3. Color adjustment and color conversion can be repeated.

In FIG. 6, the memory 74 is used as a frame memory for YMCK data. External device 6 to external I
The RGB data input through the / F7 is synchronized with the pixel synchronizing signal at the time of input, and the image processor 3 performs YM
It is converted into CK data and stored in the memory 74. Here, if the image processor 3 is parameterized to be through or the image processor 3 is bypassed and stored in the memory 74, the YMCK system external data can be output.

In FIG. 7, image data is output in three steps. In the first step shown in (a), RGB data input from the external device 6 through the external I / F 7 is stored in the memory 74 for one page. At this time,
The memory 74 is used as a frame memory for RGB data.

In the second step shown in (b), RGB
To YMCK data conversion is performed. Memory 74
RGB data read from the image processor 3
After being converted into YMCK data by, it is stored in the memory 74 again. When the conversion of all data is completed, the memory 74 becomes a frame memory for YMCK data. (C)
In the third step shown in (3), YMCK data is read from the memory 74 in synchronization with the pixel synchronizing signal for output and sent to the printer 33 for image output.

The feature of the configuration of FIG. 7 is that the second step operates asynchronously with the data input from the external device 6 and the data output to the output system 5, so that the hardware configuration of the image processor 3 can be simplified. The configurations of FIGS. 5 and 6 require a high-speed image processing circuit (image processor) to synchronize with the input / output of data. That is, an image processing circuit of four systems corresponding to each color of the conversion color YMCK,
When performing pixel-sequential or line-sequential conversion in time division, the circuit itself may be one system, but a circuit that operates at four times the speed of the pixel clock is required.

In FIG. 7, in order to construct a system of only the printer mode without the copy mode, when high speed is not required so much, the conversion to the YMCK data is allowed in a time division manner using a unique clock. The image processing circuit can be constructed at low cost.

FIG. 8 shows the YMCK data in the delay memory mode (memory 74) in the main controller 67 of FIG.
Is used as a delay memory for YMCK data)
FIG. 3 is a main part circuit diagram showing a configuration example of a memory 74 used for the above and a memory control circuit thereof. In this example, since the order of transfer to the recording paper in the image forming system is K → M → Y → C,
The MYC data are L and 2 respectively for the K data.
It is necessary to delay by L and 3L.

Therefore, the memory amounts of the memories (MEM) 74a, 74b, and 74c used for delaying the data are W × M × L × M × N and W × M × 2L × M, respectively.
× N, W × M × 3L × M × N (bit). The data input to each of the memories 74a to 74c is the pixel clock CLK (pixel synchronization signal) for the number of pixels of each memory.
Are read out when they are counted.

Reference numerals 81 to 83 denote memories 74a to 74, respectively.
An address generator (AG) for accessing c, W × M × L × M, W × M × 2L × M, W ×, respectively.
It operates as an M × 3L × M base counter. Although it is expected that the gap between the image forming units will be slightly different depending on the machine, the memories 74a to 74c are prepared in a larger amount corresponding to the difference and the set values of the address generators 81 to 83 are changed. By doing so, it is possible to correct a slight deviation.

FIG. 9 is a circuit diagram of essential parts showing a configuration example of the memory 74 and its memory control circuit used in the frame memory mode of RGB data in the main controller 67 of FIG. Note that the multiplexer 72 shown in FIG. 1 is omitted here. In this example, if each pixel has a gradation of 8 bits, 24 bits for 3 colors
Since it is t / pel, it has a memory configuration of 24 bits per word.

The memories 74a to 74e each have a capacity (1 block) corresponding to the interval between the image forming units. However, the last memory 74e has a capacity corresponding to the fraction when all the memory is allocated in order from 0 by the above capacity. Reference numeral 84 is an address generator for accessing each of the memories 74a to 74e.
It functions as a counter that operates in synchronization with LK, and when the number of pixels for one block is counted, the carry signal C is output and the counter output value is reset at the same time.

Reference numeral 85 is a phase signal generator (PG) for indicating the positional relationship between the recording paper and the image forming unit, which counts the carry signal C output from the address generator 84 and inputs the data to the memory. Memory block 74
Select from a to 74e. When outputting data, it is necessary to read data in parallel from a maximum of four memory blocks corresponding to each image forming unit. Since one block corresponds to the interval corresponding to the image forming units, the address signal can be commonly used in each memory block.

Parameters for each color of K, M, Y, and C are set in the image processing circuits (IP) 3a to 3d of the image processor 3, respectively. The memory block to be referenced changes as the phase progresses, but the multiplexer (M
UX) 86 to 89, the correspondence between the memory block and the image processor is changed according to the phase signal.

Table 1 shows the operation of each of the multiplexers 86 to 89 at this time. Since there is a gap between the image forming units, there is a deviation in the period during which each image forming unit forms an image, but in the phase not involved in image forming, selective output of data input from each memory is prohibited (see “Table 1”). (Corresponding to “×”), an image signal corresponding to white is output, and output of dust data due to data outside the effective area is suppressed.

[0064]

[Table 1]

Final delay amount fine adjustment circuit (DLY)
Reference numerals 90 to 92 are circuits for correcting the deviation of the image forming unit interval from the target value, and are delay circuits capable of delaying about 1 to 2 mm. In FIG. 9, the image processor 3 has four image processing circuits 3a to 3 corresponding to each color.
However, when the distance between the image forming units is larger than ⅓ of the maximum size recording paper, the recording paper contacts at most three image forming units at any given time. Therefore, even the image processor 3 outputs the data of the effective image area only from at most three image processing circuits at the same time, so that three image processing circuits are sufficient.

FIG. 10 is a main part circuit diagram showing another example of the configuration of the memory 74 and its memory control circuit used in the frame memory mode of RGB data in the main control unit 67 of FIG. Are denoted by the same reference numerals. In this example, the image processor 3 is composed of three image processing circuits 3a to 3c. Table 2 shows the operations of the multiplexers 93 to 99 and the image processing circuits 3a to 3c.

[0067]

[Table 2]

First, the image processing circuit 3a performs image processing for the first color K. After that, the image processing circuits 3b and 3c perform image processing of M and Y colors which are the second and third colors, respectively. In phase 3 and thereafter, the image is outside the K-color effective image range and newly becomes the C-color effective image range that is the fourth color. Therefore, the image processing circuit 3a switches to the C-color image processing parameter to perform processing. To

Unlike FIG. 9, the multiplexers 96 to 99 are provided in order to cope with the above because the relationship between the image processing circuits 3a to 3c and the output colors is not fixed in this circuit configuration.

FIG. 11 is a main part circuit diagram showing still another configuration example of the memory 74 and its memory control circuit used in the frame memory mode of the RGB data in the main control unit 67 of FIG. In this example, reading from the memory 74 can be performed from four addresses in a time division manner. FIG. 12 shows a timing chart for storing RGB data in the memory 74, and FIGS. 13 and 14 show timing charts for reading RGB data from the memory 74. In addition, M in FIG. 13 and FIG.
Y and C are Mofs, Yofs, and Cof, which will be described later, respectively.
means s.

At the time of image input, the address generator 100 is operated in synchronization with the pixel clock of the input system to store RGB data in the memory 74. When outputting an image, the address generator 100 is operated in synchronization with the pixel clock of the output system 5 to output an address signal for reading the K color data. The address difference corresponding to the read timing difference of another color is set to the offset address Mofs, Yofs, Cofs.
Is given from the system controller 65 of FIG. 3, and its absolute address is calculated using the adders (ADD) 101 to 103.

In order to read the data corresponding to each color within one pixel clock in a time-division manner, a phase signal generator 104 which operates with a clock CLK4 that is four times the pixel clock CLK is provided. The phase signal corresponds to the read color, and the address for the memory 74 is switched using the multiplexer 105 according to the phase signal. Further, the latches (FF) 106 to 109 are provided to hold the data for outputting each color for one pixel clock period,
The clock is generated by the clock generation circuit 110 for output data latch, and it is ¼ corresponding to the phase signal.
A pixel clock with a different timing is used.

With this configuration, it is necessary to access the memory 74 at a high speed with a clock that is four times the pixel clock CLK, but the delay amount can be adjusted simply by changing the offset address. Therefore, the delay amount shown in FIG. The adjusting circuits 90 to 92 are unnecessary. Even when the pixel clock is high speed, the access speed to the memory can be reduced if the data of consecutive pixels is collectively accessed and the parallel / serial converter is used to separate the data for each pixel again. You can also

FIG. 15 is a main part circuit diagram showing a configuration example of the memory 74 used in the frame memory mode of YMCK data in the main control unit 67 of FIG. 3 and the memory control circuit thereof. In this example, in the memory 74, memories 74a to 74d having the same capacity are assigned to the respective colors of YMCK. The address generators 111 to 114 for the respective memories 47a to 47d count up in synchronization with the pixel clock CLK and operate to be reset by a counter reset signal output from the address generator controller (AGC) 115.

The address generator controller 115 receives a data input start signal as a start signal START at the time of image input, and outputs a counter reset signal to the address generators 111 to 114 at the same timing from the terminals S0 to S3. However, although YMCK data is input in parallel, it can be input in frame sequential by controlling the write enable signal to the memory 74 so that only the block corresponding to the input color is enabled.

At the time of image output, an image formation start signal is input as the start signal START, and the pixel clock is counted by the interval compensation of the image forming unit to generate a signal delayed from the start signal START to generate terminals S0 to S0. Three
Output from. With these signals, the address generators 111 to 114 can shift the address generation start timing by an amount corresponding to the interval of the image forming unit. Therefore, the YMCK data is output to each image forming unit of the output system 5 at a desired time-delayed interval. Can be sent to the unit. At this time, the delay amount can be finely adjusted by adjusting the timing of starting address generation.

Parallel / serial converter (PS) 116
.About.119 are used in the plotter mode. Here, the plotter mode is a mode in which the normal printer mode performs multi-value output of a plurality of bits per pixel for each color, while YMCK is represented by 1 bit per pixel for each color.
Refers to the value output mode. Normally, when inputting / outputting to / from the memory 74 in the printer mode, when attention is paid to a certain color, the same number of plural bits of data are accessed in synchronization with respective pixel clocks at the time of input and output.
No serial conversion is needed.

Therefore, the parallel / serial converter 1
16 to 119 output the input data as they are in the printer mode (MODE is a multi-valued mode). On the other hand, in the plotter mode, 1 pixel 1bi at the time of input
To increase the data transfer efficiency even at t, the same number of bits (N) as the number of bits in the printer mode is input in synchronization with the pixel clock. That is, at the time of input, data of a plurality of pixels will be input to the same address of the memory 74. At the time of image output, it is necessary to send the image data to the output system 5 in synchronization with the pixel clock. However, since N bits, that is, data for N pixels are accessed from the memory 74 at one time, reading from the memory 74 is not possible. The output pixel clock may be divided by N. Therefore, as the clock for each of the address generators 111 to 114, a signal obtained by dividing the pixel clock by N is used.

The data for N pixels read from the memory 74 are parallel / serial converted by the parallel / serial converters 116 to 119 in synchronization with the pixel clock.
It is sent to the output system 5 without passing through the image processor 3 at the timing of bit / 1 pixel clock. Here, in the case of binary input data of a character / line drawing image such as CAD output or map data, it is sufficient that the seven colors RGBYMCK can be distinguished, and the intermediate color has little meaning as image information.
Therefore, not only is image processing such as color correction and gradation processing unnecessary, but in some cases the original contrast and sharpness of the binary image may be reduced, leading to image quality deterioration.

FIG. 16 is a main part circuit diagram showing another configuration example of the memory 47 and its memory control circuit used in the frame memory mode of YMCK data in the main control part 67 of FIG. 3, and a part corresponding to FIG. Are denoted by the same reference numerals. In this example, the plotter mode image data is divided into a plurality of recording sheets and can be output. As described above, in the plotter mode, the data amount is 1 / N as compared with the image data of the same size in the printer mode. Conversely, with the same memory amount, in the plotter mode, image data having an area N times larger than that in the printer mode can be stored in the memory 74.

CAD (C
Omputer Aided Design) drawing output and map data hard copy output are possible. In the case of the drawing, the number of gradations per pixel is binary, and the output size is A1, A0.
It is often a large size such as a plate. In the image forming device,
The maximum size of the recording paper is often about A3 size, and when outputting a large size image, the host computer side had to reduce the image data or divide it into an appropriate size and send it to the plotter.

When the YMCK frame memory in the printer mode has an A3 size memory with a gradation number of 8 bits per color, the plotter mode can store 8 times the A0 size image data. Therefore, the data up to A0 version may be sent to the plotter without any special processing on the host side. In this embodiment, when image data that exceeds the maximum recording paper size is received in the plotter mode, the image data stored in the memory 74 is divided and output for each of a plurality of recording papers. As an example thereof, a case will be described in which image data is divided into nine and output as shown in FIG.

The image areas divided into nine are numbered from 1 to 9. Since the image data of one image area is output by one image forming process, in this case, the output of the image data of all image areas is completed by continuously performing the image forming process nine times, Different divided images are formed on the recording paper. Here, it is conceivable that the 9 sheets of recording paper on which the divided images have been formed will be joined or bound together later, but a margin area is secured on each of the recording sheets so that this joining can be performed easily. Or
A mode is provided to secure the binding margin area for binding.

FIG. 18 shows an example of the margin area on each recording sheet on which divided images are formed according to this embodiment. Since the margins (shown by diagonal lines) may be provided on one side of the adjacent recording papers, some or all of the marginal area is not necessary on the recording papers at the end portions like the image numbers 3, 6, 7, 8, and 9. is there.
19 (a) to 19 (d) show different examples of the markers indicating a part of the margin area. That is, (a) is a solid line marker, (b) is a broken line (dotted line) marker,
(C) shows a marker by a short line, (d) shows a marker by a point, respectively.

By combining the marker data with the original image data and outputting the combined marker data, it is possible to facilitate the operation of joining the images. The markers may be single color even if the image is full color or multicolor. At this time, since the Y color has poor visibility, it is preferable to use the M, C, or K colors. Further, in the image forming system, in order to ensure the separability of the recording paper and the fixing roller, a recording prohibited area (blank area) may be provided at the leading end of the recording paper.
In such a case, it is not necessary to separately provide a blank area if a margin area is provided at the leading end of each recording paper as shown in FIG.

FIGS. 21A to 21C show different examples of the binding margin area on the recording paper on which divided images are formed according to this embodiment. The binding margin (indicated by diagonal lines) can be provided either vertically or horizontally on the recording paper, but may be selected by the operator from the operation unit. Also, when divided output is performed, it may not be clear how the images formed on a plurality of recording papers are connected. Therefore, each recording paper is numbered and a map showing the connection is created. It is convenient to output.

22 (a) and 22 (b) show an example in which image numbers are given to the margin area and the margin area on the recording paper on which divided images are formed according to this embodiment. As can be seen from this figure, image numbers are given to the margin area and the margin area which are non-image parts so that the image information will not be missing depending on the image number. FIG. 23 shows an example of a connection map of divided images formed on a plurality of recording sheets according to this embodiment. It is composed of a grid that divides each image and an image number.

Returning to FIG. 16, the operation of the circuit will be described. In the plotter mode, the difference between the divided output and the circuit of FIG. 15 is that the image data to be accessed is not in a continuous address space on the memory 74.
FIG. 24 shows the order of memory access. If the size of the large image data in the main scanning direction is Xsize and the start address of the image block (image 5 here) to be divided and output is OFS, the start address of each line is shifted by Xsize.

The address generator controller 115 outputs the image formation start signal START from the terminals S0 to 3 by shifting the timing by the interval compensation of the image forming unit corresponding to each color when outputting the image. The offset address generators (OAG) 120 to 123 load the start address OFS of the image area given from the system controller 65 of FIG. 3 each time the image area to be output is updated when the image formation start signal START is input, Line sync signal LSY
Each time NC is input, the start address of the pixel data of the new line is calculated and output from the terminal Q.

The address generators 111 to 114 output the head address data for each line output from the offset address generators 120 to 123, respectively, to the line synchronization signal L.
It is loaded when SYNC is input, and the pixel clock is counted up in synchronization with the clock CLK obtained by dividing the pixel clock by N. Then, the address data at this time is output from the terminal Q and used as the address of the corresponding memory. The terminal M also outputs a margin marker output signal and an output inhibition signal (mask signal) for the non-image area (image formation inhibition area) with reference to the address data.

Output control circuits (OC) 124-1 at the final stage
27 operates so as to forcibly output recording dots when the margin marker output signal is active, and output non-recording dots when the mask signal is active. Similar to the case of FIG. 15, the parallel / serial converters 116 to 119 output the input data as they are when the mode signal MODE is multi-valued, and divide the pixel clock by N when it is binary in the plotter mode. The N-bit binary image data input in synchronism with is converted into parallel / serial so that each pixel data becomes 1-bit data synchronized with the pixel clock.

The character generator 128 outputs numerical font data as an image number from the terminal Q. The numerical value to be output and the output position are instructed by the system controller 65 each time the image is output, and the output timing is adjusted using the address data obtained from the address generator 114. The font data is sent to the output control circuit 127 to instruct whether it is a recording dot or a non-recording dot. In this example, the numbers are output in C color, but other colors may be used.

When the output of the image data on the nine recording sheets is completed, the data showing the connection map of the divided images is subsequently output. The grid lines can be output in the same manner as when the margin marker is output for each recording sheet, and the image numbers can be output in the same manner as when the numerical values are output for each recording sheet. The output position of the marker or numeral is determined by the system controller 65 from the address generator and the character generator 128.
Should be specified in.

Thus, the memory control for each memory mode has been described. However, when constructing a system capable of selecting a plurality of memory modes, a plurality of memory control circuits 130a to 130n are provided as shown in FIG. The selector 131 may select the control signal for the memory 74 according to the memory mode signal. Further, in the above-described embodiment, only the RGB system is explained as the input data, but the conversion of the color system is possible even for other color system data such as L * a * b *, L * u * v *, YIQ. By changing the circuit, the same effect as that of the above-described embodiment can be obtained.

Furthermore, the output data is not limited to the YMCK four-component system, but can be easily applied to the case of the YMC three-component system or the two-color or other combination three-color system. The embodiment in which the present invention is applied to a digital color copying machine has been described above, but the present invention is not limited to this.
It can also be applied to other color image forming apparatuses such as color facsimiles and color printers.

[0096]

As described above, according to the color image forming apparatus of the first aspect, RGB input from the outside are input.
1 page memory of image data of system (RGB image data
Memory used as the frame memory of the data).
After memorizing, the time difference is calculated from the four addresses in that memory.
Only reads the image data of four systems in parallel, that each fraction
Since the image data is converted from RGB system to YMCK system in parallel and sent to the image forming unit, the amount of memory used can be reduced,
External input data can be output at low cost.

According to the color image forming apparatus of the second aspect, the distance between the transfer portions of the image carrier of each image forming unit is set to 1/3 or more of the length of the maximum transfer material in the conveying direction , and input from the outside.
Once RGB image data for one page is stored in the memory
After memorizing, the time difference is calculated from the three addresses of the memory.
Image data of 3 systems are read out in parallel, and each of them is read.
Converts image data from RGB system to YMCK system in parallel
Sent to the image forming unit, the amount of memory used is reduced , and
One image data of the RGB system it is possible to reduce the circuit for converting the image data of YMCK system a.

According to the color image forming apparatus of the third aspect, the operation of the memory is changed depending on whether the image data to be image-formed is the internal input data or the external input data.
If the image data is from the internal input means,
Is converted to YMCK image data.
After storing the image data, the image data is stored in the memory.
The memory to correct the image forming timing of the image forming unit.
Delay of YMCK image data used to
It operates as a memory and the image data to be stored is externally input.
In the case of image data from the force means, the memory is RGB system
Of the image data of)), memo
Function as a frame memory for RGB image data
RGB system input from external input means
After storing one page of image data in memory,
The image data of 4 systems are set in parallel from 4 locations in Mori with a time difference.
Data and read each image data in parallel to RGB system
From the YMCK system and send it to the image forming unit.
The amount of memory used can be reduced, and internal input data can be saved at low cost.
External input data can be output .

[0099] According to the color image forming apparatus according to claim 4, the image data to be imaged is or internal input data externally
Change the flow of image data depending on whether it is input data (internal
The image data from the input means is processed by the image processing means.
Image data from external input means
Is an image read from the memory after it is stored in the memory
Image processing is performed on the data by image processing means.
Select the data flow as shown below, and input from external input means.
When forming an image based on the image data
After storing one page of image data in the memory, the memo
Images of multiple systems in parallel from different locations with a time difference
Data is read and each image data is used as image processing means.
Predetermine image data of different color systems in parallel
It is converted to 1-component data of and sent to the image forming unit.
Can reduce memory usage, and
Easy color adjustment on input without re-receiving data
It is Ru can be.

[0100]

[0101]

[Brief description of drawings]

FIG. 1 is a block diagram of a main portion showing only a portion of a main control portion 67 of FIG. 3 relating to the present invention.

FIG. 2 is an overall configuration diagram of a digital color copying machine showing an embodiment of the present invention.

FIG. 3 is a block diagram of a main part of a control system of the copying machine of FIG.

FIG. 4 is an explanatory diagram showing a flow of image data in a copy mode in the circuit of FIG.

FIG. 5 is an explanatory diagram showing a flow of image data in the printer mode.

FIG. 6 is an explanatory diagram showing another example of the flow of image data in the printer mode.

FIG. 7 is an explanatory diagram showing still another example of the flow of image data in the printer mode.

8 is a memory 7 of FIG. 1 used in a delay memory mode of YMCK data in a main controller 67 of FIG. 3;
4 is a main part circuit diagram showing a configuration example of a memory control circuit 4 and its memory control circuit.

9 is a principal part circuit diagram showing a configuration example of the memory 74 and its memory control circuit of FIG. 1 which are also used in the frame memory mode of RGB data.

10 is a principal part circuit diagram showing another configuration example of the memory 74 and its memory control circuit of FIG. 1 which are also used in the frame memory mode of RGB data.

11 is a main part circuit diagram showing still another configuration example of the memory 74 and its memory control circuit of FIG. 1 which are also used in the frame memory mode of RGB data.

FIG. 12 is a diagram showing an RG in the memory 74 of the memory control circuit of FIG.
It is a timing diagram which shows operation | movement at the time of storing B data.

FIG. 13 is a diagram showing a memory control circuit of the memory control circuit shown in FIG.
It is a timing chart which shows a part of operation at the time of reading GB data.

FIG. 14 is a timing chart showing the continuation thereof.

15 is a main-portion circuit diagram showing a configuration example of the memory 74 of FIG. 1 used in the frame memory mode of YMCK data in the main control unit 67 of FIG. 3 and a memory control circuit thereof.

16 is a circuit diagram of a main part showing another configuration example of the memory 74 of FIG. 1 and a memory control circuit thereof which are also used in the frame memory mode of YMCK data.

FIG. 17 is an explanatory diagram for explaining division output of image data according to this embodiment.

FIG. 18 is an explanatory diagram showing an example of a margin area on each recording sheet on which a divided image is formed according to this embodiment.

FIG. 19 is an explanatory diagram showing different examples of markers that represent a part of the margin area.

FIG. 20 is an explanatory diagram showing another example of the margin area on each recording sheet on which divided images are formed according to this embodiment.

FIG. 21 is an explanatory diagram showing a different example of a margin area on a recording sheet on which a divided image is formed according to this embodiment.

FIG. 22 is an explanatory diagram showing an example in which an image number is given to each of a margin area and a margin area on a recording sheet on which divided images are formed according to this embodiment.

FIG. 23 is an explanatory diagram showing a connection map example of divided images formed on a plurality of recording sheets according to this embodiment.

24 is an explanatory diagram for explaining the operation of the memory control circuit of FIG.

25 is a principal block diagram showing a peripheral circuit including a memory 74 of FIG. 1 and a plurality of memory control circuits corresponding to various memory modes in the main control unit 67 of FIG.

FIG. 26 is a block diagram showing an example of a control system of a conventional color image forming apparatus.

27 is a conceptual diagram showing the relationship between the delay memory for each color and the image carrier of the image forming unit in the color image forming apparatus of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Image reading unit 2, 3 Image processor 3a-3d Image processing circuit 5 Output system 6 External device 7 External I / F 9,71-73,86-89,93-99,105 Multiplexer 34a-34d Photosensitive drum 35a- 35d Laser light emitting device 36K, 36C, 36M, 36Y Developing device 37a
37d Transfer unit 65 System controller 66 Operation panel 67 Main controller 68 Printer controller 74 Memory 81-83, 84, 100, 111-114 Address generator 85, 104 Phase signal generator 90-92 Delay amount adjusting circuit 101- 103 adder 106-109 latch 110 clock generation circuit 115 address generator controller 116-119 parallel / serial converter 120-123 offset address generator 124-127 output control circuit 128 character generator 130a-130n memory control circuit 131 selector

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04N 1/29 H04N 1/21 H04N 1/46 H04N 1/60

Claims (4)

(57) [Claims] 1. A color having four image forming units, wherein a color image is formed by sequentially transferring images formed in parallel on four image carriers of the image forming units to a transfer material. In an image forming apparatus, a memory for storing one page of RGB type image data input from the outside and four memories of the memory are provided with a time difference.
There is provided means for reading out image data of four systems in parallel, and for converting each image data in parallel into data of a predetermined one component of YMCK image data, and the image of YMCK system converted by the means. Data in parallel said
Color images are formed by sending them to each image forming unit.
Color image forming apparatus is characterized in that so as to I. 2. A color having four image forming units, wherein a color image is formed by sequentially transferring images formed in parallel on four image carriers of the image forming unit to a transfer material. In the image forming apparatus, the interval between the transfer portions of the image carrier of each of the image forming units is configured to be ⅓ or more of the maximum length of the transfer material in the conveyance direction, and the RGB system input from the outside is used. Memory for storing one page of the image data of, and the image data of three systems are read in parallel from the three locations of the memory with a time difference,
Means for converting the respective image data in parallel into data of a predetermined one component of YMCK image data, and YMCK image data converted by the means.
To the image forming units in parallel
Color image forming apparatus is characterized in that so as to perform the image formation. 3. An image forming unit comprising four image forming units.
Transfer images formed in parallel on four image carriers
Color image that forms a color image by sequentially transferring to a material
-In the image forming device, Internal input means for reading the original image, An external input means for inputting color image data from the outside, A memory for storing image data,Convert RGB image data to YMCK image data
Conversion means to The image data to be stored is the image data from the internal input means.
DataIfIn, The picture Image data is converted by the conversion means
After being converted into YMCK type image data, the image data
By storing in the memoryMemoryThe product
Used to correct the image formation timing of the image unit
It operates as a delay memory for YMCK image data.
Image data from the external input means.
DataIfIn,The memory is used to store RGB type image data.
A memory control means for operating as a frame memory is provided.
Ke, By the means, the memory is used to store the RGB image data.
When operating as a frame memory, the external input
The RGB image data input from the means is stored in the memory.
After storing one page in the memory, the time difference from four locations in the memory
Image data of 4 systems are read out in parallel, and each of them is read.
The image data is converted into YM in parallel by the conversion means.
CK image data is converted to the specified one-component data.
The YMCK image data after the conversion in parallel
Color image formation is performed by sending to each image forming unit.
Let me Color image forming apparatus characterized by
Place 4. An image forming unit comprising four image forming units.
Transfer images formed in parallel on four image carriers
Color image that forms a color image by sequentially transferring to a material
-In the image forming device, Internal input means for reading the original image, An external input means for inputting color image data from the outside, Image processing means for performing processing including color system conversion on input data
When, A memory for storing image data, The image data from the internal input means is the image processing means.
Input to the memory after image processing by the external input
Image data from meansIs beforeAfter storing in memory, The
For image data read from memoryThe image processing hand
Select the data flow to perform image processing step by step
Data selection means, Based on the image data input from the external input means
When forming an image, the image data is stored in the memory 1
After storing the pages, the time difference is recorded from multiple locations in the memory.
Image data of multiple systems in parallel and read each
Image data are processed in parallel by the image processing means.
Change to the data of a predetermined one component of the image data of different color system
And convert the converted color image data in parallel
Each image Color image formation by sending to the unit
Let me Color image forming apparatus characterized by
Place