JPH11151833A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of performing an optimum toner saving operation corresponding to a characteristic of an image. SOLUTION: An image correction section 301 applies an image correction operation to image data sequentially transmitted from a page buffer 204. The corrected data is inputted to a first toner saving operation section 302 and a second toner saving operation section 303. When, for example, the image data is of 4 bits, the first toner saving operation section 302 executes an AND operation of the input image with a binary number of (0111) and executes an operation wherein a maximum density is degraded to a level of 7 in a hexadecimal number. The second toner saving operation section 303 executes an operation for thinning one out of two dots. The data to which each of the toner saving operations is applied is inputted to a selector 304. One of the data is outputted in response to an instruction by a user through a host device or a panel device.

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 more particularly, to a toner saving function of a laser printer, a copying machine, and the like, and more particularly, to an image forming apparatus applicable to an ink jet printer, a thermal transfer printer, and the like.

[0002]

2. Description of the Related Art In recent years, an increasing number of electrophotographic printers have a toner save function capable of reducing the amount of consumed toner. This is an effective function when it is desired to minimize the amount of consumed toner even if the quality of the output image is deteriorated. For example, a typical method is to reduce the number of dots to be printed to reduce toner consumption by performing dot thinning processing every few dots on the entire image area, but various other methods are also available. It is considered.

[0003]

However, when toner save processing is performed, for example, lines are broken in characters / line drawings, characters cannot be read, and gradation is lost in photographic images. is there. Various methods have been considered in order to solve these problems. However, since all of these methods perform one type of processing on the entire image area, in the case of an image in which a character / line image and a photographic image are mixed, letter/
In many cases, both the processing for line drawings and the processing for photographic images are not optimal.

The present invention has been made in consideration of the above-described circumstances, and has as its object to provide an image forming apparatus capable of performing an optimal toner saving process according to the characteristics of an image. It is.

[0005]

According to a first aspect of the present invention, there is provided an image forming apparatus capable of outputting multi-valued data.
A plurality of toner save processing means for saving toner consumption corresponding to an input image, and a toner save processing selecting means for selecting one toner save processing means from the plurality of toner save processing means. Thus, an optimal toner saving process can be performed according to the properties of the input image.

According to a second aspect of the present invention, in the first aspect of the present invention, the toner save processing selecting means selects the toner save processing means in accordance with a user setting. The toner save process can be performed.

According to a third aspect of the present invention, in the first aspect of the present invention, the image processing apparatus further comprises an area determining means for determining whether the image area is a character / line drawing or a photographic image, and the toner save processing selecting means is provided by the area determining means. It is characterized in that the toner save processing means is selected according to the result of the determination, so that the optimal toner save processing can be performed on the image in that area.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the image processing apparatus further comprises an edge detecting means for detecting an edge portion of the image, wherein the toner save processing selecting means includes a determination result by the area determining means and the edge detection. The toner save processing means is selected according to the detection result of the means, and the toner save processing which is optimal for the image in the area and causes little image quality deterioration can be performed.

[0009]

FIG. 1 is a view for explaining an example of an image forming apparatus to which the present invention is applied. Hereinafter, an embodiment of the present invention will be described in the case of a black and white laser printer, but the present invention is not limited thereto. FIG.
FIG. 1A is a diagram showing a system according to the present embodiment, in which 100 is a computer, and 200 is a printer. Normally, a user creates a document using the screen of the computer 100, a keyboard, and document creation software, and transfers the created document to the printer 200 through the printer driver 101. The printer driver 101 converts the content to be printed into command or language data, and
Interprets the data to form an image.

FIG. 1B is an internal block diagram of the printer 200 shown in FIG. A CPU 201 controls the entire controller in accordance with a program in the program ROM 203, a mode instruction from the panel device 208, and a command from the host device 100. 202 is
This is a nonvolatile storage device NVRAM that stores the contents of a mode instruction from the panel device 208 and the like.

A program ROM 203 stores a control program for the controller. 204 is
A RAM used as a work memory of the CPU 201, an input buffer for input data, a page buffer for print data, a memory for download fonts, and the like. 2
Reference numeral 05 denotes an engine interface that communicates commands, statuses, and print data with the engine 206. Reference numeral 206 denotes an engine that actually performs printing.

Reference numeral 207 denotes a panel interface for communicating commands and status with the panel device 208. Reference numeral 208 denotes a panel device for notifying a user of a printer state or giving a mode instruction. 209
Is a host interface that communicates with the host computer 100, and is typically a Centronics or RS232
C and the like. Reference numeral 210 denotes a disk interface for communicating with the disk device 211.

A disk device 211 stores various data such as font data, programs and print data, such as a floppy disk device or a hard disk device. Reference numeral 300 denotes an image processing unit that corrects an edge of an image and performs a toner save process.
05.

FIG. 2 is a view for explaining an embodiment of the image forming apparatus according to the present invention. Page buffer (RA
M) For image data sequentially sent from 204,
The image correction unit 301 performs image correction processing such as edge correction, and the corrected data is supplied to a first toner save processing unit 302 and a second toner save processing unit 30.
3 is input. For example, when the image data is 4 bits, the first toner save processing unit 302 performs an AND operation on the input image with the binary display 0111 to reduce the maximum density to 7 in hexadecimal display, thereby reducing the toner consumption. The amount can be reduced by about half. This means that the dots are not lost simply by lowering the dot density, so it can be said that the toner saving process is optimal for character / line images.

The second toner save processing unit 303
By reducing the number of dots every other dot, the amount of toner consumption can be reduced to about half. This can be said to be a toner save process that is optimal for a photographic image because the gradation can be kept relatively high. Each of the data subjected to the toner save processing is input to the selector 304, and either one of the data is output to the engine interface 205 in accordance with an instruction from the host device 100 or the panel device 208 from the user.

According to the first aspect of the present invention, as described above, by providing a plurality of toner save processes, an optimal toner save process can be performed according to the properties of an input image.

Further, according to the invention of claim 2, as described above,
The toner save can be arbitrarily selected in accordance with an instruction from the user, whereby the toner save process according to the user's request can be performed.

FIG. 3 is a view for explaining another embodiment of the image forming apparatus according to the present invention. Page buffer 20
4, the image correction unit 301 performs image correction on the image data sequentially transmitted from
It is determined whether 5 is a character / line drawing area or a photographic image area. The selector 304 outputs either the first toner save processing data or the second toner save processing data according to the determination result. As a result, it is possible to output an image that has been subjected to the optimal toner save processing to the character / line drawing area and the optimal toner save processing to the photographic image area.

According to a third aspect of the present invention, a character /
By discriminating between a line drawing area and a photographic image area, and selecting a toner save processing according to the discrimination result, it is possible to perform an optimal toner save processing on an image in the area.

FIG. 4 is a view for explaining another embodiment of the image forming apparatus according to the present invention. Page buffer 20
The image correction unit 301 performs image correction on the image data sequentially transmitted from No. 4 and the area determination unit 305 determines the area, and the edge detection unit 306 detects an edge portion of the image. The selector 304 outputs data that is not subjected to the toner save processing for the character / line drawing area and the edge part based on the area determination result and the edge detection result. As a result, the density of the edge portion of the character or the line drawing is increased, and the image can be clearly seen, so that the toner saving process with less image quality deterioration can be performed.

According to a fourth aspect of the present invention, as described above, an edge portion of an image is detected, and a toner save process is selected in accordance with the detected result, so that the image is optimal for the image in that region and the image is degraded. This makes it possible to perform a toner save process with a small amount.

In the above, for the sake of simplicity, the case where there are two types of toner save processing units has been described. However, the present invention is not limited to this. Can be applied. Further, the present invention can be applied not only to a black-and-white laser printer but also to a color printer, an ink jet system, and the like.

[0023]

According to the first aspect of the present invention, in an image forming apparatus capable of outputting multi-valued data, a plurality of toner saving processing means for saving toner consumption corresponding to an input image, Since there is a toner save processing selecting means for selecting one toner save processing means from a plurality of toner save processing means, it is possible to perform an optimal toner save processing according to the properties of the input image.

According to a second aspect of the present invention, in the first aspect of the present invention, the toner save processing selecting means selects the toner save processing means according to a user setting. Can be.

According to a third aspect of the present invention, in the first aspect of the present invention, there is provided an area determining means for determining whether the image area is a character / line drawing or a photographic image, and the toner save processing selecting means comprises:
Since the toner saving processing means is selected according to the result of the determination by the area determining means, the optimal toner saving processing can be performed on the image in the area.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the image forming apparatus further comprises an edge detecting means for detecting an edge portion of the image, wherein the toner save processing selecting means includes a determination result by the area determining means and the edge detection. Since the toner save processing means is selected according to the detection result by the means, it is possible to perform the toner save processing which is optimal for the image in the area and causes little image quality deterioration.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of an image forming apparatus to which the present invention is applied.

FIG. 2 is a diagram illustrating an embodiment of an image forming apparatus according to the present invention.

FIG. 3 is a view for explaining another embodiment of the image forming apparatus according to the present invention.

FIG. 4 is a view for explaining another embodiment of the image forming apparatus according to the present invention.

[Explanation of symbols]

100: computer, 101: printer driver, 2
00: Printer, 201: CPU, 202: NVRA
M, 203: Program ROM, 204: RAM, 20
5 ... Engine interface, 206 ... Engine, 2
07: panel interface, 208: panel device,
209: Host interface, 210: Disk interface, 211: Disk device, 300: Image processing unit, 301: Image correction unit, 302: First toner save processing unit, 303: Second toner save processing unit, 30
4 selector, 305 area determination unit, 306 edge detection unit.

Claims (4)

[Claims] 1. An image forming apparatus capable of outputting multi-valued data, comprising: a plurality of toner save processing means for saving toner consumption corresponding to an input image; and a plurality of toner save processing means. An image forming apparatus comprising: a toner save processing selecting means for selecting one toner save processing means. 2. The image forming apparatus according to claim 1, wherein said toner save processing selecting means selects the toner save processing means according to a user setting. 3. The image forming apparatus according to claim 1, further comprising an area determining unit that determines whether an image area is a character / line image or a photographic image, wherein the toner save processing selecting unit determines the image by the area determining unit. An image forming apparatus wherein a toner save processing unit is selected according to a result. 4. The image forming apparatus according to claim 3, further comprising an edge detecting means for detecting an edge portion of the image, wherein said toner save processing selecting means determines a result of said area determining means and said edge detecting means. Wherein the toner save processing means is selected according to the detection result of the image forming apparatus.