JPH09244340A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image of excellent quality without fog by consuming the toner in an image forming device by a toner consuming means before indicating the toner end after the integrated operation time of a plurality of developing devices reaches the prescribed value to prevent the deteriorated toner from being mixed with the new toner. SOLUTION: The electrostatic latent image formed on a surface 1a of a photosensitive body 1 is manifested by the toner 3 in a plurality of developing devices 2 to be the toner image. Presence/absence of the toner 3 in the developing devices 2 is detected by a toner end detecting sensor and the detected signal is outputted to a control part 17, and the control part 17 indicates the toner end to a toner end indicating means 4. An integrating means 5 integrates the operation time of the developing devices 2, and the toner in the developing devices 2 is consumed by a toner consuming means 6 (an image forming part) before the toner end indicating means 4 indicates the toner end after the integrated operation time reaches the prescribed value.

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 such as an electrophotographic copying machine, a printer, a facsimile machine or a composite machine thereof, and more particularly to a plurality of developing devices of two or more colors. The present invention relates to an image forming apparatus having the same.

[0002]

2. Description of the Related Art Among image forming apparatuses, an electrophotographic copying machine having a developing device for two or more colors has been conventionally used in a design office or the like. It is also used in business establishments, etc. The reason why color copiers with two or more colors have become popular is that it is possible to simultaneously form two color toner images on a photoconductor and transfer the toner images onto a transfer sheet at a time. As a result, it is advantageous in terms of cost as compared with the conventional one, and the image forming time is shortened. However, even for a user who installs and uses such an image forming apparatus, most of the image colors of the document generally used are black, and the consumption of toner of colors other than black is extremely small. In addition, when the operator selects the mode after checking the color etc. in the original image, no inconvenience occurs,
When an operator does not check the colors in the original image and always sets a mode of two or more colors to perform copying, the developing device using colors other than black consumes almost no toner. Nevertheless, it is always operating. In such a case, the toner in the developing device of a color other than black deteriorates rapidly, and thus the deteriorated toner and the new toner to be replenished are mixed,
There is a problem that so-called fog occurs and a high-quality formed image cannot be obtained.

[0003]

Although the conventional image forming apparatus is provided with a plurality of developing devices containing toners of different colors, only black toner is used exclusively. Since toners of colors other than black are not used, deterioration progresses quickly in the developing device. When new toner is replenished in the developing device containing the deteriorated toner as described above, there is a problem that so-called fog occurs due to the mixing of both toners and a high-quality formed image cannot be obtained. It was An object of the present invention is to solve such a problem. That is, a high-quality formed image with no fog is obtained by preventing the deteriorated toner in the developing device and the newly supplied new toner from being mixed with each other. The purpose is to do.

[0004]

In order to achieve the above object, the present invention according to claim 1 is an image forming apparatus having a plurality of developing devices, wherein a photoconductor on which an electrostatic latent image is formed, and the above-mentioned photoconductor. A developing device for developing the electrostatic latent image formed on the body,
Toner end display means for displaying the toner end based on a detection signal from the toner end detection means for detecting the absence of toner in the developing device, integrating means for integrating the operating time of the developing device, and integrating by the integrating means. A toner consuming unit that consumes toner in the developing device after the predetermined operating time has reached a predetermined value and before the toner end is displayed,
It is characterized by having. The present invention according to claim 2 is the image forming apparatus according to claim 1, wherein after the operating time accumulated by the accumulating means reaches a predetermined value, the default of the image forming mode of two or more colors is released. Is the main feature. According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, after the operating time accumulated by the accumulating means reaches a predetermined value, a default of an image forming mode of two or more colors is set. The main feature is that the image forming apparatus has a warning unit that warns.

[0005]

According to the first aspect of the invention, the image forming apparatus constructed as described above has a predetermined operation time accumulated by the accumulating means of a plurality of developing devices for developing the electrostatic latent images formed on the photosensitive member. After reaching the value, before the toner end display means displays the toner end, the toner consuming means consumes the toner in the developing device so that the deteriorated toner and the replenished new toner are mixed. (EN) It is possible to provide an image forming apparatus capable of preventing formation of a fog and obtaining a high quality formed image. According to another aspect of the present invention, after the operating time accumulated by the accumulating means of the plurality of developing devices for developing the electrostatic latent image formed on the photoconductor reaches a predetermined value, the default of the image forming mode of two or more colors is set. To prevent deterioration of the toner to a minimum and prevent the deteriorated toner from mixing with new toner to be replenished, resulting in a high-quality formed image without fog. An image forming apparatus can be provided. According to another aspect of the present invention, after the operating time accumulated by the accumulating means of the plurality of developing devices for developing the electrostatic latent image formed on the photoconductor reaches a predetermined value, the default of the image forming mode of two or more colors is set. When the setting is made, the warning means gives a warning to reliably prevent the deteriorated toner from being mixed with new toner to be replenished, so that a high-quality formed image without fog can be obtained. To be able to provide equipment.

[0006]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the structure of an example of an image forming apparatus of the present invention in a partial cross section. This image forming apparatus is rotatably supported and rotates in a direction indicated by an arrow A on a surface 1a of a photoreceptor 1. The electrostatic latent image formed on the surface is visualized by the toner 3 in the plurality of developing devices 2, specifically, by the two-component developer 3a of the first developing device 2a and the one-component toner 3b of the second developing device 2b. Is converted into a toner image, and the toner image is transferred by the transfer device 14 to the transfer paper 15
The toner image transferred to the upper side is fixed by a fixing device (not shown) by pressing and heating and fixed, and then discharged onto a paper discharge tray by a paper discharging means (not shown). Operation panel 1
The toner end display unit 4 on 6 detects the presence or absence of the toner 3 in the developing device 2 by a toner end detection sensor (not shown) and outputs the detection signal to the control unit 17, and the control unit 17 based on this detection signal. The toner end display means 4 displays the toner end.

The detection of the presence or absence of the toner 3 in the developing device 2 is
The toner end is detected by the P sensor method or the F sensor method. Here, in the P sensor method, an image of a P sensor pattern located below the original scale (not shown) is developed as a toner image on the surface 1a of the photoconductor 1, and the density of the image is reflected by a reflection photosensor (P Sensor), and the data detected by the control unit 17 is determined to detect the toner end. In the F sensor system, a part of the two-component developer 3a is passed through a sensor bobbin (not shown) to detect the toner concentration in the two-component developer 3a and detect the toner end. In this method, specifically, the amount of the two-component developer 3a flowing out from a sensor (not shown) is constant, but the transmittance changes due to the change in toner concentration, that is, the ratio of carrier to toner. , The F sensor bobbin is used to detect the change in the self-inductance of the detection coil as the resonance frequency and to detect the toner end based on this value. The accumulating means 5 is means for accumulating the operating time of the developing device 2, and after the operating time accumulated by the accumulating means 5 reaches a predetermined value and before the toner end display means 4 displays the toner end, the developing device. The toner in 2 is consumed by the toner consuming means (image forming section) 6. Therefore, the deteriorated toner and the replenished new toner are prevented from being mixed with each other, and a high-quality formed image without fog is obtained.

FIG. 2 is a specific configuration diagram of the embodiment shown in FIG. 1. The surface 1a of the photosensitive member 1 which is rotatably supported and rotates in the direction of arrow A shown in FIG.
Is uniformly charged by a predetermined charging potential, and an image is written by the laser light of the first exposure unit 9a of the exposure unit 9 to form an electrostatic latent image. The electrostatic latent image formed on the surface 1a of the photoconductor 1 is developed by the two-component developing device of the first developing device 2a. Then, the surface 1a of the photoconductor 1
Is uniformly charged with a predetermined charging potential by the second charging device 8b, and the image writing of the second color is performed by the LED of the second exposure unit 9b. These image writing signals are 1
The first and second colors are sent from a scanner or other device (not shown) such as a personal computer.

The electrostatic latent image formed on the surface 1a of the photoconductor 1 on which the image of the second color has been written by the LED of the second exposure means 9b is developed by the second developing device 2b in the non-magnetic non-contact one-component development. Developed by the device. The one-component toner 3b in the non-magnetic non-contact one-component developing device of the second developing device 2b is sent to the sponge roller 11 by the agitator 10 and then rubbed against the developing roller 12 by the sponge roller 11. At this time, the one-component toner 3b is triboelectrically charged, and the surface of the toner is flattened by the blade 13 and charged on the developing roller 12 to form a thin layer. The thin layer formed on the developing roller 12 approaches the surface 1a of the photoconductor 1 to develop the second color. In this way, the visualized toner images of the two colors formed on the surface 1a of the photoconductor 1 are transferred onto the transfer paper 15 by the transfer device 14, fixed by a fixing device (not shown), and not shown. The paper is ejected to a paper ejection tray or the like by the paper ejecting means.

On the other hand, the surface 1a of the photoconductor 1 after the transfer is cleaned by the cleaning device 18 to scrape off and clean the one-component toner 3b that has adhered and remained, so that it is ready for image formation in the next step. There is. The accumulating means 5
Is configured to count the number of transfer sheets transferred by a counter (not shown) in the two-color mode and to integrate them via the control unit 17, but in addition to this, a timer (not shown) Second developing device 2b
It is also possible to measure the actual operation time of and to integrate it via the control unit 17.

The toner consumption means 6 consumes the toner in the developing device 2 before the toner end display means 4 displays the toner end display. The consumption here means
Irrespective of the actual image forming operation, the toner is made to adhere to the photoconductor and then the toner is removed by the cleaning means to consume the toner. After replenishing the one-component toner 3b, after the number of transfer sheets or the operating time accumulated by the accumulating means 5 reaches a predetermined value determined by an experiment or the like, the toner end detecting means causes the inside of the first developing device 2a When the toner end of the two-component developer 3a is detected, all the LEDs of the second exposure means 9b are turned on before the toner end display means 4 displays the toner end, and the one-component toner 3b in the second developing device 2b is turned on. After being attached to the surface 1a of the photoconductor 1, the cleaning device 1
It is scraped off by 8 and consumed. This operation will be described in detail with reference to FIG.

After replenishing the one-component toner 3b,
After the number of transfer sheets or the operating time accumulated by the accumulating means 5 reaches a predetermined value determined by an experiment or the like,
When the default of the image forming mode of two or more colors is set through the control unit 17 by the operation panel 16 or the like, 2
The default setting of the image formation mode of more than color is canceled, and it is also set to the monochrome mode. This operation will be described in detail with reference to FIG. In this way, when the monochrome mode is set, it is only necessary to check the document image and operate only the usable colors. However, after canceling the default setting of the image forming mode of 2 colors or more,
When the defaults of the image forming modes of two or more colors are set from the operation panel 16 or the like via the control unit 17, the warning display or the warning sound of the warning means 7 provided on the operation panel 16 or the like causes the second developing device. It also warns that the deterioration of the one-component toner 3b in 2b is progressing. Therefore, the deteriorated toner and the replenished new toner are prevented from being mixed with each other, and a high-quality formed image without fog is obtained.

FIG. 3 and FIG. 4 are flow charts showing the operation of the above-mentioned embodiment, and these operations will be described below. In FIG. 3, first, when the control unit 17 receives a document reading start or an image output signal from the exposure unit 9 (step 1), the presence or absence of a second color image is detected from the document or the image output signal (step 2), If there is an image of the second color (step 3), the operating time of the second developing device 2b is measured and integrated by the integrating means 5 (step 4), and the integrated number of transferred sheets or the integrated operating time is set in advance. After reaching the value (step 5), when the toner end detection means detects the toner end of the two-component developer 3a in the first developing device 2a (step 6), the toner consumption means 6 causes the second exposure means. All the LEDs of 9b are turned on and the second developing device 2
After the toner 3b in b is consumed (step 7), the toner end display means 4 turns on the toner-free toner end of the two-component developer 3a in the first developing device 2a (step 8), and the process ends. Incidentally, when there is no image of the second color (step 3), when the accumulated number of transferred sheets or the operating time has not reached the predetermined value set in advance (step 5), the toner end display means 4 causes the first development. Even when the toner end of the two-component developer 3a in the apparatus 2a is not detected (step 6), the process ends. Therefore, the deteriorated toner and the replenished new toner are prevented from being mixed with each other, and a high-quality formed image without fog is obtained.

In FIG. 4, when the control section 17 receives an image reading signal from the document reading start or exposure means 9 (step 11), it detects the presence or absence of a second color image in the document or in the image output signal ( (Step 12) If there is an image of the second color (YES in step 13), the operating time of the second developing device 2b is measured and integrated by the integrating means 5 (step 14), and the integrated number of transferred sheets or operating time is preset. When the default of the image forming mode of two or more colors is set from the operation panel 16 or the like via the control unit 17 after the predetermined value is reached (step 15) (step 1).
6) After canceling the default setting of the image forming mode of two or more colors and setting the monochrome mode (step 17), the image forming mode of two or more colors is again set through the control unit 17 from the operation panel 16 or the like. When the default is set (step 18), the warning display or warning sound of the warning means 7 provided on the operation panel 16 or the like indicates that the deterioration of the one-component toner 3b in the second developing device 2b is progressing. A warning is given (step 19) and the process ends. As an example of the warning display of the above warning means 7, the deterioration of toner is progressing on the operation panel 16 "Because the used amount of 2 colors is small. Avoid setting the 2-color image formation mode. ] Is displayed as a warning. When there is no image of the second color (step 13), when the accumulated number of transferred sheets or the operating time has not reached the preset predetermined value (step 15), the control unit 17 is operated by the operation panel 16 or the like.
If the default of the image forming mode for two or more colors is not set via (step 16), the operation panel 16 is again used.
When the defaults of the image forming modes of two or more colors are not set through the control unit 17 due to the above conditions (step 18), the process is also terminated. Therefore, it is possible to prevent the deteriorated toner from being mixed with the new toner to be replenished, and it is possible to provide an image forming apparatus in which a high-quality formed image without fog is obtained.

[0015]

Since the present invention is configured as described above, according to the invention of claim 1, the integrating means of a plurality of developing devices for developing the electrostatic latent image formed on the photosensitive member. Since the toner consumption means consumes the toner in the developing device before the toner end display means displays the toner end after the operating time accumulated by the method reaches a predetermined value, the toner is replenished with deteriorated toner. It has become possible to provide an image forming apparatus capable of obtaining a high quality formed image in which fogging does not occur by preventing mixing with new toner.

According to the second aspect of the present invention, after the operating time accumulated by the accumulating means of the plurality of developing devices for developing the electrostatic latent image formed on the photosensitive member reaches a predetermined value, two or more colors Since the default of the image forming mode of has been canceled so that the deterioration of toner can be minimized, it is possible to prevent the deteriorated toner from mixing with new toner to be replenished, and to prevent fog from occurring. It has become possible to provide an image forming apparatus capable of obtaining a formed image of high quality.

According to the third aspect of the present invention, after the operating time accumulated by the accumulating means of the plurality of developing devices for developing the electrostatic latent image formed on the photoconductor reaches a predetermined value, two or more colors When the default image forming mode is set, a warning is given by a warning means, so it is possible to reliably prevent the deteriorated toner from mixing with the new toner to be replenished, and to prevent fog from occurring. It has become possible to provide an image forming apparatus capable of obtaining a formed image of high quality.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating an outline of an image forming apparatus according to an exemplary embodiment of the present invention.

FIG. 2 is an enlarged explanatory surface view for explaining a main part of the image forming apparatus showing the embodiment of the present invention.

FIG. 3 is a flowchart illustrating a main operation of the image forming apparatus according to the exemplary embodiment of the present invention.

FIG. 4 is a flowchart illustrating another main operation of the image forming apparatus according to another embodiment of the present invention.

[Explanation of symbols]

1 photoconductor, 1a surface, 2 developing device, 2a first developing device, 2b second developing device, 3 toner, 3a two-component developer, 3b one-component toner, 4 toner end display means, 5 integrating means, 6 toner consumption Means, 7 warning means, 8 charging device, 8a first charging device, 8b second charging device, 9 exposing means, 9a first exposing means, 9b second exposing means, 10 agitator, 11 sponge roller, 12 developing roller, 13 Blade, 14 transfer device, 15 transfer paper, 16 operation panel, 17 control unit,
18 Cleaning device

Claims (3)

[Claims] 1. An image forming apparatus having a plurality of developing devices, wherein a photoconductor on which an electrostatic latent image is formed, a developing device for developing the electrostatic latent image formed on the photoconductor, and an inside of the developing device. No toner, the toner end display means for displaying the toner end based on the detection signal from the toner end detection means, the integrating means for integrating the operating time of the developing device, and the operating time integrated by the integrating means And a toner consuming unit that consumes the toner in the developing device after the predetermined value has been reached and before the toner end is displayed, the image forming apparatus. 2. The image forming apparatus according to claim 1, wherein
An image forming apparatus, wherein after the operation time accumulated by the accumulating means reaches a predetermined value, the default of the image forming mode of two or more colors is released. 3. The image forming apparatus according to claim 1, wherein a warning is issued that a default of an image forming mode for two or more colors is set after the operating time accumulated by the accumulating means reaches a predetermined value. An image forming apparatus having a warning unit.