JPH03291673A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain an image which is efficient and of a good quality by adjusting and controlling a set value of each unit related to image formation in the image forming device according to image ratio and imparting the most appropriate environmental condition for image formation. CONSTITUTION:When image data is processed by a controller 20 and fetched to a control part 16 as image information, the image ratio of the image information is detected by a detected by a detection part 16A of the image ratio K, and the image ratio is judged by the control part 16. Data of fixing temperature T against the image ratio stored in ROM 16-1 is fetched by a data selection part 16B based on this detected and judged image ratio, a heating device 9A is adjusted and controlled, and a fixing heater 9H is made to be a fixed temperature. That is, the fixing temperature is made high as shown in graph a, and the fixing of the toner is improved. Thus, an image of good quality can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an image forming apparatus such as a printer or a copying machine using an electrophotographic method, and in particular to an image forming apparatus based on an image ratio of image data processed by a controller. It is concerned with operating each unit, such as a fixing device and a transfer charger, that make up the device under optimal conditions.

(Prior Art) FIG. 3 shows the configuration of a laser printer as an example of a conventional image forming apparatus. To give an overview of the operation of this printer, recording paper 2 is fed from paper feeder 1 in the direction of arrow A.
is conveyed to a latent image carrier consisting of a drum-shaped photoreceptor 4 in a timed manner by a pair of registration rollers 3.

The photoreceptor 4 is rotationally driven in a clockwise direction, the surface of which is charged by the charger 5, and irradiated with laser light from a laser optical system 6 to form an electrostatic latent image on the photoreceptor.

This latent image is made visible by toner when passing through the developing device 7, and this visible image is transferred to the recording paper 2 conveyed to the photoreceptor 4.
A transfer charger 8 transfers the visible image onto the recording paper, and a fixing device 9 fixes the transferred visible image on the recording paper.

The recording paper that has left the fixing device 9 is then discharged to a paper discharge section 11 in the direction of arrow B.

On the other hand, residual toner is removed from the photoreceptor 4 after the visible image has been transferred by a cleaning device 13 having a cleaning blade 12 , and the charge is removed by a charge removal brush 14 .

The toner removed from the photoreceptor is collected by a collection roller 16 into a toner collection chamber 15 and stored therein. 1
0 is the printer main body, 6 is a control unit (CPU), 17 is a paper feed roller, and 18 is a paper discharge roller.

Conventional image forming apparatuses, as typified by the above-mentioned printer, have a device content unit, that is, a charger 5. Developing device 7, transfer charger 8. The operating conditions of the fixing device 9 and the like were constant.

(Problem to be solved by the invention) For example, even if one page is solid black (image ratio 100%), there is only one lowercase letter on page one (image ratio several % below the decimal point).
), the setting values for each unit were the same.

As an example, in the case of the fixing device 9, a fixing heater 9H is provided inside the fixing roller 9R, and the surface temperature of the fixing roller 9R is detected by a thermistor, and the surface temperature is controlled to be constant by a # control unit 16 (microcomputer: CPU). has been done.

FIG. 2 shows graphs a and b of the fixing temperature T and image ratio of the present invention and the conventional fixing device, and the conventional (graph b) is constant regardless of the image ratio K (solid black is 100%). It can be seen that it is preserved.

For this reason, there are few problems when the image ratio is a few percent, but when the amount of toner is large, such as in solid black, the ratio of thermal energy to toner becomes small, resulting in significantly poor fixing performance. Furthermore, even if the temperature of the fixing heater 9H is set high in advance for cases where the image ratio is large in order to avoid this, the image ratio is small for most prints, so this is a waste of thermal energy. Therefore, it is not efficient. This also applies to other units.

In view of the above-mentioned circumstances, it is an object of the present invention to make it possible to obtain images of the same high quality even if images with different image ratios are printed.

(Means for Solving Problem m1) 3-4- In order to achieve the above object, the present invention provides an image forming apparatus using an electrophotographic method, in which the image ratio of image data input to the image forming apparatus is adjusted. a means for detecting, a means for storing in advance a setting value corresponding to an image ratio for each unit constituting the image forming apparatus, and storing in the storage means based on the image ratio detected by the image ratio detection means. The image forming apparatus is characterized in that it has a means for taking in setting values corresponding to the image ratio and controlling each unit of the image forming apparatus.

(Function) In the present invention, setting values for each unit according to the image ratio are stored in advance, and drive control is performed by selecting the setting values for each unit according to the image ratio of the image data. As the optimal environmental conditions for image formation, a high quality image can always be obtained according to the image ratio, and each unit can be driven efficiently.

(Embodiment) The first construction drawing shows a block diagram of an apparatus according to an embodiment of the present invention, and shows the case where it is implemented in the fixing device W9 of the laser printer shown in FIG. 3. As shown in the figure, the control unit 16 (microcomputer: CPU) in the printer main body IO has setting values (second
It has a ROM 16-1 in which graph a) in the figure is stored in advance. A temperature detection sensor 9S of the fixing device M9 is connected to this control section 16, and the surface temperature of the fixing roller 9R is detected and input. Further, the control unit 16 is configured to input a control signal to the heating device w9A that heats the fixing heater 9H.

The control unit 16 also includes a person, an output interface (Ilo
) 19 is connected to a controller 20 that converts image data sent from a host machine (not shown) into image information. Data selection unit 16 that reads data from ROM 16-1 that stores set values
B.

Next, the operation of this embodiment will be explained. Now controller 2
When the image data is processed in 0 and taken into the control unit 16 as image information, the image ratio detection unit 16A detects the image ratio of the image information.

The control unit 16 determines the image ratio. Based on the detected image ratio, the data selection unit 16B takes in the data (setting value) of the fixing temperature T for the image ratio stored in the ROM 16-1, adjusts and controls the heating device 9A, and 9H is set to a predetermined fixing temperature.

The operation of this adjustment control will be explained with reference to graph a in FIG. 2. When the image ratio K is low (approximately 10% or less), the fixing temperature T is maintained as usual (graph b).

And when the image ratio K is high (approximately 10% or more).

If the fixing temperature T is constant as in the past, the ratio of thermal energy to toner will be small and the fixing performance will be poor, so in this embodiment, the fixing temperature is increased as shown in graph a to improve toner fixing. I try to get high quality images.

The above describes the case where the fixing temperature is adjusted and controlled based on the image ratio of the image data, but other units such as the voltage adjustment in the case of the charger and transfer charger, and the adjustment of the toner supply amount in the case of the developing device, etc. By doing
You can get a similar effect.

(Effects of the Invention) As explained above, the present invention adjusts and controls the setting values of each unit involved in image formation in an image forming apparatus based on the image ratio, and provides optimal environmental conditions for image formation, thereby achieving efficient image formation. You can get high quality images.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention, FIG. 2 is a diagram showing a graph of fixing temperature and image ratio of the present invention and a conventional fixing device, and FIG. 3 is an example of an image forming apparatus. 1 is a diagram showing the configuration of a laser printer of FIG. 9...Fixing device, 9A...Heating device, 9R...
・Fixing roller, 9H...Fusing heater, 9S...
・Temperature detection sensor, lO...printer body, 16...
・Control unit (microcomputer: CPU), 16A・
... Image 7- Ratio detection section, 16B ... Data selection section, 16-1.
...ROM, 19...I/O interface CI1
0), 20...controller.

Claims (1)

[Claims] In an image forming apparatus using an electrophotographic method, a means for detecting an image ratio of image data input to the image forming apparatus and a setting value corresponding to the image ratio of each unit constituting the image forming apparatus are stored in advance. and a set value corresponding to the image ratio stored in the storage means based on the image ratio detected by the image ratio detection means;
An image forming apparatus comprising means for controlling each unit of the image forming apparatus.