JPH0744644B2 - Color image processor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a color image processing apparatus capable of printing and monitoring color image information.

2. Description of the Related Art As a method of displaying, modifying, and processing a color image to take a hard copy, the system system shown in FIG. 1 is considered. The image data in the large-capacity image memory 15 (for example, magnetic disk, tape, etc.) is transferred to the image memory 4 placed near the terminal 2 via the communication line 14 at the request of the terminal 2. The memory capacity of the image memory 4 is, for example, 512 × 512 ×
It has three colors of 8-bit blue-violet (BLUE VIOLET, hereafter B), green (GREEN, hereafter G), red (RED, hereafter R), and this data is for each processing circuit described later. After that, it can be monitored by the monitor 9.

On the other hand, the contents of the image memory 4 can be connected to processing by the CPU of the terminal 2 and output to the color printer 13 by switching the switch 5.

Here, when outputting and printing an image to the color printer 13, it is adjusted by a color conversion circuit (for example, a masking circuit) 10 and a density conversion circuit 11 so as to obtain a desired color, and is further binarized by a halftone dot generator 12. Make dots for halftone output for color printers that can only do it.

Here, in order to monitor the contents of the image when the hard copy output is performed in advance, the color conversion circuit (for example, masking circuit) 6 and the density conversion circuit 7 are inserted even while outputting to the color monitor 9. Although the color conversion circuits 6 and 10 and the density conversion circuit 7.11 have the same data transfer speed and different output targets, they are functionally the same but different in circuit. The density conversion circuit 8 is for correcting the output characteristic of the printer 13 and the output characteristic of the monitor 9 (CRT) and is an inverter or the like. However, the adjustment switch 5 is linked so that the correction on the monitor is reflected.

Note that FIG. 2 shows a 4-drum type color printer as an example of a color printer. In FIG. 2, reference numeral 18 denotes a scanning optical system, and the scanning optical system transmits required image information from an image memory (not shown). (Laser beam)
This light beam is formed as an image on the photosensitive drum 19 which is arranged in parallel corresponding to cyan (C), magenta (M), yellow (Y), and black (Bl). A developing device 20 is arranged in the vicinity of the drum 19, and a charging device 22 is arranged facing the photosensitive drums 19 on the side of a conveyor belt 21 for conveying a recording sheet (not shown).

[Problems to be Solved by the Invention] However, in the above system, the color conversion circuits (6 and 1) are used.
0) and density conversion circuits (7 and 11) are required for the monitor and the printer, respectively. Further, there is a drawback that the monitor image cannot be seen during output to the color printer by switching the switch 5.

In view of the above point, the present invention has an object to provide an image processing apparatus capable of visually recognizing a monitor image even during output to a printer.

In order to achieve such an object, the image processing apparatus of the present invention should output an image memory for storing a given color image signal for one screen (memory 4 in FIG. 3 in the embodiment), and output the contents of the image memory to a color monitor. First reading means for reading the image memory, reading means for reading the image memory to output the contents of the image memory to a color printer,
Second reading means having a reading speed lower than that of the first reading means; first output means for outputting the contents of the image memory read by the first reading means to a color monitor; and the second Second output means for outputting the contents of the image memory read by the reading means to the color printer, the first reading means and the second means for performing color monitor output during output of image data to the color printer. Arbitration means for arbitrating the reading operation to the reading means.

An embodiment of application of the present invention will be described with reference to the drawings. FIG. 3 shows a color processing system which is an embodiment of the present invention. The image data of the large-capacity image memory 15 in the host computer 1 is taken into the image memory 4 at the request of the terminal 2. At this time, DMA (direct memory a
ccess) (switch 16 is B). The contents of the image memory are output to the monitor (for example, CRT) 9 via the color conversion circuit 6 and the density conversion circuits 7 and 8. Therefore, the color adjustment is performed by looking at the monitor, and the finally determined image is stored in the memory 4. This method is performed by switching the output time series signal from the density conversion circuit 7 to the input terminal of the memory 4 and switching the switch 16 to the A side. This method will be described later.

The converted image can be monitored by the monitor 9 via the CRT density correction circuit 8.

On the other hand, CPU processing is also possible from the terminal 2 via the interface 3.

The processed image data is output to the color printer through the halftone dot generator 12 (switch 17 on the C side).

In the above system, the color conversion circuit and the density conversion circuit as described above can be used as one set, and the cost can be reduced.

Next, the operation of the memory 4 will be described. The memory 4 divides the standard access time into 1/2 for one pixel. One is for access for CRT display 9, the other is for access time for CPU or color printer output. It is connected. Therefore, a memory access address counter (corresponding to the first reading means of the present invention) for the CRT display and a memory address counter for CPU or color printer output (corresponding to the second reading means of the present invention). .),
It is switched alternately within one access time. Therefore 2
One output data value is also switched alternately for the CRT and for the CPU or color printer by 1/2 cycle time (corresponding to the arbitration means of the present invention).
It is necessary to send data at about 70 ns per pixel of × 512 pixels. This is impossible from the current speed of D-RAM,
For this reason, the output data bus takes as much as 64 bits and the speed is relatively low.

CPU or color printer output can be much slower than CRT output. For this reason, the output data to the CPU and color printer is relatively slow and is output with a gate time of 1/2 cycle time.

By performing the internal division of 1/2 in this way, the output data of the processing result of the above-mentioned color conversion can be written in the same memory by using 1/2 time for the CPU or the color printer. This sets the switch 16 of the input data to the A side,
17 switches are opened by A or cut by a gate in a circuit,
The output signal to the monitor with 1/2 cycle time is used as the write signal to the memory with the next 1/2 cycle time. As described above, since the data in the image memory 4 is converted into the corrected data, the respective memories can be independently output to the color printer 13 at different timings.
Therefore, output to a 4-drum color printer is also possible. Further, the output information to the printer can be simultaneously monitored by the monitor.

[Effects of the Invention] According to the present invention, the color monitor and the color printer are respectively provided with the reading means, and further the arbitration means for arbitrating between the two reading operations is provided, so that the color printer prints. The image can be monitored, and the usability is improved.

Furthermore, in the present invention, the image memories can be made common without providing a dedicated memory for each of the color monitor and the color printer, and an image printed during color printing can be displayed with a simple structure. You can monitor.

[Brief description of drawings]

FIG. 1 is a diagram showing a system for taking a hard copy of a color image. FIG. 2 is a diagram showing an example of a 4-drum type color printer. FIG. 3 is a diagram showing a color processing system.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location 9192-5L G06F 15/72 310

Claims (1)

[Claims] 1. An image memory for storing a given color image signal for one screen, a first reading means for reading the image memory so as to output the contents of the image memory to a color monitor, and the contents of the image memory. Is a reading means for reading the image memory to output to a color printer,
Second reading means having a reading speed lower than that of the first reading means; first output means for outputting the contents of the image memory read by the first reading means to a color monitor; and the second reading means The second access means for outputting the contents of the image memory read by the color printer to the color printer, and the reference access time for one pixel is divided into two so as to perform the color monitor output while the image data is being output to the color printer. Then, by alternately switching one for the access time of the color monitor and the other for the access time of the color printer within the reference access time, the reading by the first reading means and the second reading means is performed. A color image processing apparatus comprising: an arbitration unit that arbitrates an operation.