JP2003015494A - Image forming device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reuse color-mixed recycled toner regardless of color mixture amount and also to control the change of the color reproducibility of a formed image by newly proposing a path for mixing color-mixed toner recovered by a cleaning means and new toner, a mixing method therefor, a mixing rate detecting method therefor and mixing rate control therefor in a toner recycling method for a tandem type electrophotographic color copying device using a plurality of photoreceptors and an intermediate transfer body. SOLUTION: This image forming device has a plurality of image carriers, and a cleaning means for removing toner adhering to the image carriers after developing an image on each image carrier by electrification, exposure and development and transferring a toner image to an intermediate transfer body, and has the path for returning the color-mixed recycled toner transferred to the intermediate transfer body and recovered by the cleaning means to each developing means in terms of the second and succeeding colors and the path for supplying the new toner to each developing means.

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 and method using an electrophotographic process, and more specifically, it is provided with a developing device, an image carrier, and a cleaning device for each color. The present invention relates to an image forming apparatus and method for reusing the generated toner.

[0002]

2. Description of the Related Art In a color image forming apparatus using an electrophotographic process, a full-color image is formed by forming toner images of three colors or four colors on an image carrier and superposing them on an intermediate transfer body or a transfer body. ing. A method of sequentially forming toner images of four colors by one or two image carriers, an image carrier for each of the four colors, a developing device for forming a toner image on the image carrier, and cleaning of the image carrier. There is a system with a cleaning device that does, the latter is usually
This is a so-called tandem system in which each color is linearly arranged in the moving direction with respect to the intermediate transfer body or the transfer belt. Such a tandem system is excellent in speeding up because it can simultaneously form toner images of four colors. Further, since a cleaning device for the image carrier is provided for each color, the collected toner cleaned from each image carrier is recovered again. Easy to recycle for image formation. Further, in a color image forming apparatus, since the number of colors is large and a document having a large image area ratio such as a photographic document is often output as compared with black and white, resource saving, space saving, and running cost reduction are achieved. From the point, recycling of toner is extremely important. But in reality, there are some problems. One is a mixture of upstream colors to a more downstream color process. Some countermeasures have already been proposed for such a problem of color mixture. That is, in Japanese Patent Laid-Open No. 2000-242152,
A part of the toner transferred onto the intermediate transfer member has a charging polarity opposite to the normal charging polarity due to the electric discharge when transferring from the image carrier on the upstream side to the intermediate transfer member. When the toner of the color on the downstream side is transferred, it is considered that the cause is that the toner is transferred to the image carrier in reverse, and a recovery means is provided to utilize the fact that the reverse-transferred toner has the opposite charging polarity. Therefore, color mixture on the image carrier is prevented.
In this method, it is necessary to provide a collecting means near each photoconductor, which is not necessary in the past, which is disadvantageous in terms of space and cost, and the toner having an opposite polarity charge is originally stable in regular charge polarity. Therefore, the charge amount of the opposite polarity toner is not stable. Most of the toner has a charge that is almost "0", and cannot be completely collected by the above-mentioned collecting means, so that color mixing cannot be prevented.

Further, in Japanese Patent Laid-Open No. 10-293432, although the apparatus is not in tandem, a method of eliminating the background potential before transfer is adopted in order to prevent reverse charging of toner which causes reverse transfer. ing. Although it is said that the toner image before transfer does not scatter by adjusting the degree of charge removal, in reality the charge is rapidly reduced by light removal, so the toner in the image area moves to the periphery and the image blurs. I will end up.
If the charge is removed less, discharge will occur and color mixture due to reverse transfer cannot be prevented. Thus, it is very difficult to completely prevent color mixing. Further, in JP-A-8-63067 and JP-A-2000-267366, problems of the toner collected by the cleaning device include aggregation and deterioration of charging characteristics, and the supply ratio of recycled toner is determined to optimize process conditions. However, it is not a proposal to make full use of recycled toner by detecting or predicting the color mixture state. In other words, the purpose is different.

[0004]

The technical contents disclosed in the above-mentioned respective prior arts are all disadvantageous in terms of space and cost, and there is an instability of charging of the toner. It hasn't reached the point of control. The present invention is intended to solve such a problem, and by reusing a mixed toner of recycled toner regardless of the amount of color mixture, the amount of a new toner is adjusted to change the color reproduction of the formed image. The purpose is to be able to control. More specifically, firstly, a device that mixes the new toner and the recycled toner mixed with color by a mixing unit that mixes the new toner with the recycled toner mixed with color to prevent partial uneven color mixing of the toner is provided. The purpose is to provide. Further, in the above image forming apparatus, means for mixing new toner and recycled toner mixed
It is an object of the present invention to provide a device capable of more surely mixing and preventing partial color mixture unevenness by using a means having a sieve-shaped member. Furthermore, in the above device,
It is an object of the present invention to provide an apparatus that facilitates adjustment of the color mixture amount by providing a means for separately supplying a new toner and a mixed color recycled toner to the developing means.
It is another object of the present invention to provide a device that can prevent an excessive color mixture by providing a supply device that can change the supply amount of recycled toner. It is another object of the present invention to provide an apparatus that increases the accuracy of determining the supply amount by directly measuring the color mixing ratio of recycled toner. Another object of the present invention is to provide an apparatus that does not require measurement for detecting the color mixture ratio and does not need to secure a special space by calculating the color mixture ratio detection means of the recycled toner from the image signal. .

An object of the present invention is to provide an apparatus for obtaining a good image by using recycled toner and new toner with a simple structure by making the ratio of supply of recycled toner and new toner to the developing means constant. To do. Further, the color mixing ratio detection unit that detects the color mixing ratio of the toner, the toner supply amount determination unit that determines the supply amounts of the recycled toner and the new toner based on the signal from the color mixing ratio detection unit, and the toner supply amount determination unit An object of the present invention is to provide a device for avoiding excessive color mixture by providing a developing device with a supply device capable of varying the supply amount of recycled toner and new toner according to the determination. The color-mixing rate detecting means for detecting the color-mixing rate in the developing means is a device for measuring the reflection density on the developing sleeve included in the developing means, thereby making it possible to accurately know the color-mixing rate in the developing means, An object of the present invention is to provide a device that improves the accuracy of adjustment. Moreover, it aims at providing the method of achieving the object of each claim of Claim 1, 2, 4, 5, 8, and 9. Claims 5, 6, 9, 1
The toner color mixing ratio detection means described in 0 is a device for measuring the color mixing ratio of toner, and includes a light source that emits light having a wavelength having a large difference in spectral reflectance between the color A and the color mixing A + B, and a light having the wavelength. It is an object of the present invention to provide a means for easily detecting the color mixture ratio of the color A and the color B by including the light receiving unit for measuring the intensity of the color A. The method for detecting by the color mixture ratio detecting means according to claim 14 or 16, wherein the color A is added to the toner of the color mixture A + B.
And the color mixture A + B are irradiated with light having a large difference in spectral reflectance, the intensity of reflected light is measured by the light receiving unit, and the color mixture rate is determined by comparing with the reflectance of the known color A. An object of the present invention is to provide a method for easily detecting the color mixture of color A and color B by the toner color mixture ratio measuring method described below.

[0006]

The above object of the present invention can be achieved by the following means. According to the first aspect of the present invention, a plurality of image carriers, a charging and exposing unit that forms an electrostatic latent image on each of the image carriers, and a toner are attached to the formed electrostatic latent images. In an image forming apparatus having a developing unit for developing a visible image, a transfer unit for transferring the attached toner to an intermediate transfer member, and a cleaning unit for removing the toner and the like attached to the image carrier after passing through the transfer unit, When transferring the second and subsequent colors to the intermediate transfer body, the most important one is an image forming apparatus having a path for returning the recycled toner collected by the cleaning means and mixed to each developing means and a path for supplying new toner to each developing means. It is a characteristic. A second aspect of the present invention is characterized in that, in the apparatus according to the first aspect, the image forming apparatus has a mixing unit that mixes the new toner and the recycled toner mixed with each other before supplying the developing toner to the developing unit. According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the means for mixing the new toner and the recycled toner mixed in the color is mainly an image forming apparatus having a sieve-shaped member. The invention of claim 4 relates to claim 1
The described apparatus is characterized mainly in an image forming apparatus including means for separately supplying new toner and recycled toner mixed in color to the developing means. According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the color mixing ratio detection unit that detects the color mixing ratio of the recycled toner, and the recycled toner based on a signal from the color mixing ratio detection unit. The main features are an image forming apparatus having a toner supply amount determining means for determining the supply amount of the new toner and a supply device capable of varying the supply amounts of the recycled toner and the new toner according to the determination of the toner supply amount determining means. .

A sixth aspect of the present invention is characterized in that the recycled toner color mixture rate detecting means according to the fifth aspect is mainly an image forming apparatus which is an apparatus for measuring the reflection density of the recycled toner. A seventh aspect of the present invention is characterized mainly in that the recycled toner color mixture rate detection unit according to the fifth aspect is an image forming apparatus that is a calculation unit that calculates a color mixture rate from an image signal.
An eighth aspect of the invention is the image forming apparatus according to the fourth aspect, and is characterized mainly in the image forming apparatus in which the ratio of the supply of the recycled toner and the new toner to the developing unit is constant. The invention of claim 9 is any one of claims 1 to 4.
The image forming apparatus according to the item 1, wherein a color mixing ratio detection unit that detects a color mixing ratio of toner in the developing unit, and a toner that determines a supply amount of recycled toner and new toner based on a detection signal from the color mixing ratio detection unit A main feature is an image forming apparatus having a supply amount determining means and a supply device capable of changing the supply amounts of the recycled toner and the new toner according to the determination of the toner supply amount determining means. According to a tenth aspect of the present invention, the color mixture rate detecting means for detecting the color mixture rate in the developing means according to the ninth aspect is mainly an image forming apparatus which is an apparatus for measuring a reflection density on a developing sleeve included in the developing means. Characterize. The invention of claim 11 forms an electrostatic latent image by charging and exposing the surfaces of a plurality of image bearing members, and makes toner adhere to the electrostatic latent image to visualize the latent image. An image forming method for obtaining an image by forming a toner image on an intermediate transfer body by transferring the toner image on a transfer body, and the intermediate transfer body remaining on the image carrier. When the toner that has not been transferred to the top is cleaned by the cleaning device provided in each image carrier, the toners transferred to the intermediate transfer member in the second and subsequent colors are collected by the cleaning device for each color. The most main feature is an image forming method in which both the recycled toner and the new toner thus produced are used for developing the electrostatic latent image.

A twelfth aspect of the present invention is characterized in that, in the image forming method according to the eleventh aspect, the recycled toner collected by the cleaning device and the new toner are mixed and then supplied to the developing device. . Claim 13
The present invention is characterized in that, in the image forming method according to claim 11, the image forming method for supplying the new toner and the recycled toner to the developing means from separate supply ports is a main feature. A fourteenth aspect of the invention is the image forming method according to any one of the eleventh to thirteenth aspects, in which the color mixture ratio of the recycled toner is detected, and the recycled toner and the new toner are supplied based on the detected color mixture signal. The main feature is an image forming method in which the amount is determined and the supply amount of recycled toner and new toner is changed. According to a fifteenth aspect of the present invention, in the image forming method according to the thirteenth aspect, new toner and recycled toner are supplied to the developing unit at a constant rate when the toner needs to be supplied to the developing unit. The main feature is the image forming method. According to a sixteenth aspect of the present invention, in the image forming method according to the eleventh aspect, the color mixing rate of the toner in the developing unit is detected, and the supply amount of the recycled toner is determined based on the detected color mixing rate signal. The main feature is an image forming method in which the supply amount is changed. According to a seventeenth aspect of the present invention, the toner color mixing ratio detecting means according to the fifth, sixth, ninth and tenth aspects is an apparatus for measuring the color mixing ratio of the toner.
The main feature of the image forming apparatus is a light source that emits light having a wavelength having a large spectral reflectance difference between the mixed color A and B and a light receiving unit that measures the intensity of light having the wavelength. According to an eighteenth aspect of the present invention, in the method of detecting by the color mixing ratio detection means according to the fourteenth and sixteenth aspects, light of a wavelength having a large difference in spectral reflectance between the color A and the color mixing A + B is mixed with the toner of the color mixing A + B. The main feature of the toner color mixing ratio measuring method is to determine the color mixing ratio by irradiating, measuring the reflected light intensity with a light receiving unit, and comparing the data with the reflectance data for colors A + B having a known color mixing ratio.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An image forming apparatus according to the present invention has a plurality of image bearing members, each image bearing member having a charging, developing, transferring and cleaning unit, and forms a toner image on the image bearing member. After that, a so-called tandem type image forming apparatus is provided in which the toner image is transferred onto the intermediate transfer member in an overlapping manner and the toner image on the intermediate transfer member is transferred onto the transfer member to obtain an image. The toner image formed on the image carrier is transferred onto the intermediate transfer member, but some of the toner remains on the image carrier without being transferred. The remaining toner is collected by the cleaning unit provided in each image carrier. In the case of the tandem system in which the image carrier has the same number of colors, the toner of each color is cleaned in each cleaning unit, so that it is easy to collect the toner collected by the cleaning in the developing device of that color and reuse it. However, ideally, it is desirable that the respective color systems are independent and do not mix colors, but in reality, color mixing occurs. It occurs at the time of transfer from the photoreceptor to the intermediate transfer body. When the toners of the second and subsequent colors in the tandem system are transferred to the intermediate transfer body, the toner of the color transferred on the upstream side in the moving direction of the intermediate transfer body is placed on the intermediate transfer body. The toner of the upstream color is reversely transferred from the intermediate transfer member to the image carrier at the time of transferring the downstream color, the toner of the reverse transfer is collected by the cleaning of the downstream color, and the toner collected by the cleaning device on the downstream side is upstream. Color toner causes color mixing. In the case of a toner having a color mixture, the toner is mixed with the black toner and reused, or is discarded as waste toner. When all the black toner is mixed, it is difficult to balance the consumed toner and the toner supplied to the developing device. Depending on the type of image to be formed, a document such as a photographic image having little black is often used as a document, and there is a possibility that a reversal phenomenon may occur in which the amount of recycled mixed toner supplied is larger than the amount of toner consumed. All the mixed toner cleaning recovery toner,
When the toner is returned to the developing device for each color, there arises a problem that the hue of the toner in the developing device is largely different from that in the state where there is no color mixture. The present inventor has studied the contribution of the toner color mixing ratio to the hue of the final image, and as a result, by balancing the use of the mixed toner of the recycled toner and the new toner, the hue can be changed within an allowable range and the toner can be reused. I found that I can do it. Therefore, as an apparatus form, an image forming apparatus characterized in that it has a path for returning mixed toner of recycled colors to each developing means and a path for supplying new toner to the developing means for each color are effective. Found.

Embodiments of the present invention will be described below in more detail with reference to the drawings. (Embodiment 1) An experiment was conducted with the apparatus shown in FIG. In FIG. 1, the drum-shaped photoconductors 1 are arranged in order from the left.
a, the photoconductor 1b, the photoconductor 1c, and the photoconductor 1d. Since the image forming units around the photoconductor are all provided in the same manner for each photoconductor, only the photoconductor 1a will be described. Photoconductor 1a
Rotates counterclockwise. The photoconductor 1a includes a charging device 4,
It has a writing device 5, a developing device (developing means) 2, and a cleaning device (cleaning means) 3. Photoconductor 1
The toner image developed on a is the belt-shaped intermediate transfer member 6
Transcribed on. Further, the photoconductor 1 is provided on the intermediate transfer body 6.
The toner is transferred by b, the photoconductor 1c, and the photoconductor 1d, and a full-color image is formed on the intermediate transfer body 6. This full-color image is transferred onto a transfer material by a transfer section (transfer means) 7, and the transfer material is heated and fixed by a fixing section 8. On the other hand, the toner that has not been transferred to the intermediate transfer member on the photoconductor 1 a remains on the photoconductor and is collected by the cleaning device 3. Here, the leftmost image is described, but other images are almost the same. However, when the toner image is transferred from the photoconductor to the intermediate transfer body, there is already a toner image transferred on the upstream side on the intermediate transfer body, and this toner image is transferred to the photoconductor on the downstream side in reverse. The difference is that it ends up. Consider the second color photoreceptor 1b counting from the left. Photoconductor 1b
When the toner is transferred onto the intermediate transfer body 6 from the above, the toner transferred from the photoconductor 1a is already on the intermediate transfer body. When the toner is transferred from the photoconductor 1b to the intermediate transfer body 6, the intermediate transfer body and the photoconductor 1b come into close contact with each other, and a part of the toner already on the intermediate transfer body is transferred to the photoconductor 1b in reverse. Assuming that the photoconductor 1a is an image forming unit for yellow (Y) and the photoconductor 1b is for magenta (M), after the toner image is transferred from the photoconductor 1b to the intermediate transfer body, it is the transfer residual toner. And magenta toner, which is the reverse transfer toner, and yellow, which is the upstream color, are present, and both are cleaned by the cleaning device 3. The recycled toner collected by the cleaning device 3 is a mixed-color toner in which yellow and magenta are mixed. Are mixed.

FIG. 2 is an explanatory view of the toner supply path of the present invention. From a cleaning device not shown in FIG.
A collection path 24 for sending toner to the developing device 20 and a toner supply path 27 for sending new toner to the developing device are shown. In this figure, a recovery path 24 from the cleaning device to the developing device is provided on the back side of the apparatus main body, and a toner bottle 26 is provided on the front side of the apparatus.
And a replenishment path 27 for sending new toner to the developing device.
Is provided. By appropriately controlling the amount of toner sent to the developing device from both toner transport paths, it is possible to prevent excessive color mixing. The degree of color mixing is determined from the relationship between the color mixture rate and the color difference, and the degree of color mixing is determined by the target color difference. In the present embodiment, the control was performed with the target color mixing ratio within 10%. The ratio of the amount of recycled toner supplied to the developing device to the developing device was set to 1:10, and the document was printed with scenery, people, and catalogs.
The color order of the apparatus was yellow, magenta, cyan, and black in this order, and the above-described recycling was performed on magenta.
Therefore, the color mixture of yellow with respect to magenta was evaluated.
As a result of printing 1000 sheets on each original and measuring the color difference for every 100 sheets, all were within the target color difference. According to this embodiment, in the image forming apparatus according to claim 4, as in claim 8, the supply ratio of the recycled toner and the new toner to the developing unit is configured to be constant, so that the recycled toner can be used as the recycled toner even with a simple configuration. It is possible to obtain a good image by using a new toner.
To configure the color mixture of different color toners at a certain ratio and to prevent the density of the color mixture toner in the developing unit from becoming excessive, set assuming that the color mixture ratio of recycled toner is very high. Good. Even if the color mixing ratio of the recycled toner is 100%, if the device is set so as not to become excessive, there is no possibility of becoming excessive. Although the consumption of recycled toner is small, it is consumed at a constant rate.

Further, also in the image forming apparatus according to the ninth aspect, the color mixture rate detecting means for detecting the color mixture rate of the toner in the developing means, and the supply amount of the recycled toner are determined based on the signal from the color mixture rate detecting means. By providing the recycled toner supply amount determining unit and the supply device capable of changing the supply amount of the recycled toner according to the determination of the recycled toner supply amount determining unit, the supply can be adjusted according to the color mixture ratio of the recycled toner, and the color mixing can be performed. It can be prevented from becoming excessive. Here, the same processing as the processing shown in the block diagram of FIG. 5 is performed. However, the color mixture rate detected by the color mixture rate detecting means in the block diagram is the color mixture rate in the developing means in the present invention. When the color mixing rate detecting means for detecting the color mixing rate in the developing means according to claim 9 is an apparatus for measuring the reflection density on the developing sleeve included in the developing means as in claim 10, the color mixing rate detecting means is Since a certain amount of carrier + toner is conveyed, accurate measurement can be performed.

(Embodiment 2) By providing a device having a means for mixing the recycled toner mixed with the new toner before the developing device is charged into the developing device, the mixed color toner is uniformly distributed, and the color due to the non-uniform color mixture is obtained. Prevent unevenness from standing out. An apparatus for demonstrating this phenomenon is shown in FIG. The developing sleeve 31 of the developing device 30 rotates counterclockwise in the drawing during image formation. The two screws 32 for stirring the carrier and the toner rotate in different directions. Both toners are supplied from the recycled toner supply unit 36 and the new toner supply unit 37 to the pre-stirring unit 33 of the developing device. There is a pre-stirring unit 33 for mixing the recycled toner and the new toner, and a fin 38 for stirring the recycled toner and the new toner. The toner is mixed by rotating. There is a toner supply roller 39 from the pre-stirring unit 33 to the developing device, and the toner is supplied by rotating the sponge roller 39. There is a measuring unit 35 that detects the color mixture ratio. An experiment was performed to evaluate the performance using this device. Magenta toner was supplied from the recycled toner supply unit 36, cyan toner was supplied from the new toner supply unit 37, and toner was supplied to the developing device. The developing device contains cyan toner. For easy evaluation,
The same amount of toner was supplied from the recycled toner side and the new toner side. Solid image formation was performed while replenishing by such a replenishment method. After 100 images were formed, the initially monochromatic image of cyan gradually shifted in hue to the magenta side, and finally became a uniform blue image. On the other hand, when the recycled toner and the new toner are directly put in the developing device without the pre-stirring unit 33, magenta is partially mixed after printing about 10 sheets, and color unevenness in one print is conspicuous. It was While printing 100 sheets, the color gradually became closer to blue and the uneven color became less noticeable. From the results of this experiment, when the amount of the color-mixed toner is small, the unevenness of the mixing method is rather conspicuous, and it is found that sufficient dispersion of the color-mixed toner is important in the color mixing ratio of actual use. It was found that proper mixing is possible.

(Embodiment 3) Since the mixing means for mixing the new toner and the recycled toner mixed with the color is a sieve-like member, the respective toners are dispersed and mixed, and good stress is not applied to the toner. Mixing is possible. This experimental apparatus is shown in FIG. Most configurations are shown in Figure 3.
The same number as that of the developing device of FIG. Sieve 40
Corresponds to the mixing of the recycled toner and the new toner by the fin 38 in FIG. By replenishing the toner on the sieve 40 and mixing the toner through the sieve 40, both toners can be finely mixed and the mechanical stress is small, so that the toner is less likely to deteriorate. As a result of performing a color mixing experiment similar to that of the second embodiment using this apparatus,
Good color uniformity was obtained. Further, by supplying the new toner and the color-mixed toner separately to the developing means by the apparatus of the embodiment of FIG. 2, it becomes easy to adjust the color-mixing amount, and since the supply is different, only the required amount can be controlled by the control. It is possible to operate the replenishment of toner, and it is possible to adjust the state of the toner in the developing device with a small time delay.

(Embodiment 4) A color mixing ratio detecting means for detecting a color mixing ratio of recycled toner, a recycled toner supply amount determining part for determining a supply amount of recycled toner based on a signal from the color mixing ratio detecting means, and the recycling. By having a supply device that can change the supply amount of the recycled toner according to the determination of the toner supply amount determination unit, the supply can be adjusted by the color mixture ratio of the recycled toner, and it is possible to prevent excessive color mixture. FIG. 5 is a block diagram of the fourth embodiment.
Shown in. The color mixing ratio detection unit 51, the recycled toner supply amount determination unit 52, the recycled toner supply device 53, and the new toner supply device 54 are included. The color mixing ratio detection unit 51 includes a sensor controller, and based on the detection signal of the sensor,
The color mixing degree of the recycled toner is divided into levels, and a signal D indicating the level is sent to the recycled toner supply amount determination unit 52. In the recycled toner supply amount determination unit 52, based on the signal D sent from the color mixing ratio detection unit 51, signals S1 and S2 corresponding to the supplied amounts of recycled toner and new toner are supplied to the recycled toner supply device 53 and the new toner supply device, respectively. Send to 54. By controlling the amount of recycled toner supplied by such an apparatus, it was possible to form an image without causing excessive color mixing.

An example of processing in the recycled toner supply amount determination unit will be shown. The recycled toner supply amount determination unit 52 receives the data D indicating the color mixture ratio. For the input signal D, a combination of the signal A1 corresponding to the supply of recycled toner and the signal A2 corresponding to the supply of new toner is selected. Selection of combinations follows Table 1. The total value of the combination of A1 and A2 is constant, and the ratio of the supply amount of the recycled toner to the supply amount of the new toner is changed by selecting the combination. On the other hand, the total amount of toner supplied is determined by a device (not shown) that determines the total amount of supply toner. The data S indicating the supply amount sent to each recycled toner supply unit 53 and new toner supply unit 54 by the value N corresponding to the total amount is calculated as S1 = A1 * N S2 = A2 * N, and the recycled toner supply device is used. And sent to a new toner supply device. N for the total amount of supply
Corresponds to S1 and S2 by always multiplying A1 and A2 by the same N.
As a result, the supply ratio of recycled toner and new toner becomes A1: A2. Specifically, the values of S1 and S2 correspond to the rotation time of the toner supply device and control the supply amount. At this time, as the data D showing the color mixture ratio, the data showing the reflection density of the recycled toner was used. The reflection density of the recycled toner is measured at 29 in FIG. 2, and the data D is sent to the recycled toner supply amount determination unit. The means for measuring the reflection density of the recycled toner is a light source and a sensor for detecting the amount of light. As described above, in the apparatus having the structure according to the fifth aspect, the recycled toner color mixture ratio detection means 51 is a device for measuring the reflection density of the recycled toner, so that the recycled toner color mixture ratio can be directly known, and the accuracy can be improved. It has good control. As a means for knowing the color mixing ratio of the recycled toner, it is measured directly, and since highly accurate calculation and algorithm are not involved, highly accurate information can be obtained.

(Embodiment 5) The recycled toner color mixture rate detecting means according to claim 5 is replaced with a calculating section (calculating means) for calculating from an image signal as described in claim 7, thereby detecting a sensor. There is no need to install a special space, and there is no need to secure a special space. This will be described with reference to the embodiments described below. Color mixing ratio Pc in recycled toner is 2
Considering the color image forming unit, the reverse transfer rate of the toner of the first color is G, the image area of the first color is Sa, the image area of the second color is Sb, and the transfer rate is R. The amount of toner reversely transferred to the second-color photoconductor in the second-color image forming unit is Sa
* R * G, which is collected by the second color cleaning unit. Further, regarding the image formation of the second color, the amount of toner collected for cleaning is the area Sb * (1-R). At this time, Sa * R * G / ((Sb * (1-R)) +
Sa * R * G) is the color mixing ratio of the recycled toner. After n times of image formation, Sa * R * G is n respectively.
The value is the rotated value, and similarly, the color mixture ratio after n times can be estimated. It is necessary to enter the reverse transfer rate and transfer rate of the system in advance, but this value can be changed depending on environmental data such as temperature and humidity and temporal data such as the operating number of photoconductors and transfer belts. Is also possible, and the accuracy of estimation is further improved. This estimation was used to detect the color mixture ratio in the process shown in FIG. 5, and the image was formed by the apparatus shown in FIG. Since the order of colors is yellow, magenta, cyan, and black as the transfer order for the intermediate transfer belt,
The resulting color mixture is a color mixture of yellow in magenta, a color mixture of magenta in cyan, and a color mixture of cyan in black.
Evaluation was made by paying attention to these color mixture. Even after printing 1000 sheets, the color change was not noticeable.

(Embodiment 6) The construction of the developing means is as shown in FIG. The density sensor 35 measures the color mixture ratio in the developing means. In the figure, the density on the developing sleeve is measured after passing through the doctor blade 34 of the developing device. The measurement may be performed at another part in the developing device. For the measurement, the amount of color mixture is estimated by irradiating light and measuring the reflected light intensity. The figure shows a two-component developing device that develops a mixture of carrier and toner in the form of a brush due to the magnetic force inside the sleeve.
A distribution of lines of magnetic force is formed, and carriers are arranged along the lines of magnetic force. Therefore, there are parts where ears stand and parts where they sleep.
The measurement is performed on this lying part. When the measuring unit is provided inside the developing device (inside the doctor blade), the measuring device is easily soiled. In the case where the spikes are lying down after passing through the doctor blade, the carrier and toner are restrained by the sleeve, and the measurement portion is less likely to be contaminated due to scattering. Also,
As the principle of measurement, there are a method of measuring specular reflection light and a method of measuring irregular reflection light. In this embodiment, specular reflection light is used. When specular reflection light is used, noise increases when the reflectance of the surface of the sleeve is high.

In the present embodiment, the surface of the sleeve is sandblasted, and the measurement is carried out at the portion where the spikes lie down, so that the carriers are densely packed and good measurement can be performed. When the value from the measuring unit arranged at the position of FIG. 3 is used as the data D, control is performed by the apparatus shown in Example 4 and continuous image formation is performed. A good image was obtained. The toner color mixing ratio detection unit is a device that measures the toner color mixing ratio, and includes a light source that emits light having a wavelength having a large spectral reflectance difference between the color A and the color mixing A + B, and a light source that emits light having the wavelength. It is a device that easily detects the color mixture ratio of the color A and the color B by being composed of a light receiving unit that measures the intensity. A change in hue due to color mixing can be detected as a difference in spectral reflectance. An example of measuring the reflectance while changing the wavelength of the light source is shown in FIGS. 6 and 7. Figure 6
Shows a case where magenta is mixed with cyan, and FIG. 7 shows a case where yellow is mixed with magenta. The curve a is the case where there is no color mixture, and the curve b is the case where color is mixed. It can be seen that due to the color mixture, the wavelength at which the change appears is limited. Using a light source of this wavelength, the color mixing ratio can be measured from the reflectance. As a method of selecting a wavelength, there is a method of using a light source of a single wavelength such as a laser, or a method of limiting the wavelength by filtering a white light source.

(Embodiment 7) A white light source was inserted with a filter transmitting a wavelength shorter than 500 nm, and the reflectance when yellow was mixed with magenta was measured. The results are shown in Fig. 8. The horizontal axis shows the yellow color mixture rate, and the vertical axis shows the color mixture rate of 0%.
The value is standardized with the value at the time of 1 as 1. The reflectance is almost saturated at a color mixing rate of about 50%, but there is no problem because the color mixing rate of 50% or less is used for process control. According to this graph, the color mixture ratio was obtained from the reflectance and used as the data D showing the color mixture ratio of the embodiment 4, and an experiment was conducted. It is used as D and Table 1 shown below is used. In Table 1, 1 of the main measurement is divided into 8 steps from 0 to 7, so that the value was D = T * 8-1 with T being the value of the main measurement. Successive printing was performed in the same manner as in Example 4, but good images were obtained. (Table 1) Similarly, as a result of showing the reflectance of the mixed color of magenta with respect to cyan, it was measured as shown in FIG. 9, and when the same control was performed using this, the result was good. As a light source, L of short wavelength
It is also possible to use D and LED, and when the measuring unit 35 of the apparatus of FIG. 3 is equipped with a measuring device using an LD and the color mixing ratio is detected, the color mixing ratio can be detected satisfactorily.

[0021]

According to claim 1, a plurality of image carriers,
For each of the image carriers, a charging and exposing unit that forms an electrostatic latent image, a developing unit that visualizes the formed electrostatic latent image by adhering toner to it, and an intermediate toner In an image forming apparatus having a transfer means for transferring to a transfer body and a cleaning means for removing toner and the like adhering to the image carrier after passing through the transfer means, a cleaning means for transferring the second and subsequent colors to an intermediate transfer body. Since there is a path for returning the recycled toner mixed in the color mixture to each developing means and a path for supplying the new toner to each developing means, the amount of the new toner can be adjusted and used. It is possible to reuse regardless of the color mixture amount, and it is possible to control the change in color reproduction of the formed image. According to a second aspect of the present invention, the apparatus according to the first aspect has a mixing means for mixing the recycled toner mixed with the new toner before the developing means is supplied, so that the recycled toner mixed with the new toner is mixed well. However, partial uneven color mixing of toner does not occur. According to the third aspect, in the image forming apparatus according to the second aspect, the means for mixing the new toner and the recycled toner mixed with the color has the sieve-shaped member, so that the mixing can be performed more reliably and the partial It is possible to prevent uneven color mixing. According to claim 4, in the device according to claim 1,
Since the new toner and the recycled toner mixed with the color are separately provided to the developing unit, the amount of color mixture can be easily adjusted. According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the color mixing ratio detection unit that detects the color mixing ratio of the recycled toner, and the recycled toner based on a signal from the color mixing ratio detection unit. And a toner supply amount determining means for determining the supply amount of the new toner, and a supply device capable of varying the supply amounts of the recycled toner and the new toner according to the determination of the toner supply amount determining means.
Excessive color mixing can be avoided.

According to the sixth aspect of the present invention, since the recycled toner color mixture rate detecting means according to the fifth aspect is a device for measuring the reflection density of the recycled toner, the color mixture rate of the recycled toner can be directly known and supplied. The accuracy of quantity determination is increased. According to the seventh aspect, since the recycled toner color mixture rate detecting means according to the fifth aspect is a calculating means for calculating the color mixture rate from the image signal, a measurement or the like for detecting the color mixture rate is not required, and the special It is not necessary to secure a large space. According to the eighth aspect, in the image forming apparatus according to the fourth aspect, the supply ratio of the recycled toner and the new toner to the developing unit is configured to be constant, so that the recycled toner and the new toner can be formed with a simple configuration. A good image can be obtained by using. According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the color mixing rate detecting unit for detecting the color mixing rate of the toner in the developing unit, and the color mixing rate detecting unit Since the toner supply amount determining means for determining the supply amounts of the recycled toner and the new toner based on the signal and the supply device capable of varying the supply amounts of the recycled toner and the new toner according to the determination of the toner supply amount determining means, the color mixture is prevented. You can avoid being overloaded.

According to the tenth aspect of the invention, since the color mixture rate detecting means for detecting the color mixture rate in the developing means according to the ninth aspect is a device for measuring the reflection density on the developing sleeve included in the developing means, It is possible to know the color mixture ratio in the means with high accuracy and improve the accuracy of adjustment. Claims 11, 12,
According to 13, 14, 15, 16 claims 1, 2, 4,
It is possible to obtain the same effects as those obtained in the items 5, 8, and 9. According to claim 17, claims 5, 6, 9, 10
The toner color mixing ratio detection means described above is a device for measuring the toner color mixing ratio, and includes a light source for irradiating light of a wavelength having a large difference in spectral reflectance between the color A and the color mixing A + B, and a light of the wavelength. Since the light receiving section for measuring the intensity is used, the color mixture ratio of the color A and the color B can be easily detected. According to the eighteenth aspect, in the method of detecting by the color mixture rate detecting means according to the fourteenth and sixteenth aspects, the toner of the color mixture A + B is irradiated with light having a wavelength having a large difference in spectral reflectance between the color A and the color mixture A + B. Then, the color mixing ratio is determined by measuring the reflected light intensity by the light receiving unit and comparing it with the data of the reflectance with respect to the color A + B having a known color mixing ratio, so that the color mixing of the colors A and B can be easily detected.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an image forming apparatus according to the present invention.

FIG. 2 is an explanatory diagram of a toner supply path of the present invention.

FIG. 3 is an explanatory diagram of an apparatus that demonstrates Embodiment 2 of the present invention.

FIG. 4 is an explanatory diagram of an apparatus for testing a third embodiment of the present invention.

FIG. 5 is a block diagram of Embodiment 4 of the present invention.

FIG. 6 is a diagram when magenta is mixed with cyan.

FIG. 7 is a diagram when yellow is mixed with magenta.

FIG. 8 is a graph showing the reflectance measured when magenta is mixed with yellow.

FIG. 9 is a diagram in which the reflectance of a mixed color of magenta with respect to cyan is measured.

[Explanation of symbols]

1 (1a, 1b, 1c, 1d) photoconductor, 2 developing device, 2b developing device, 3 cleaning device, 4 charging device, 5 writing device, 6 intermediate transfer member, 7 transfer portion,
8 fixing unit, 20 developing device, 24 recovery path, 26
Toner bottle, 27 toner supply route, 30 developing device,
31 developing sleeve, 32 screw, 33 pre-stirring section, 34 doctor blade, 35 measuring section (concentration sensor), 36 recycled toner supply section, 37 new toner supply section, 38 fins, 39 toner supply roller,
40 sieve, 51 color mixing ratio detection means, 52 recycled toner supply amount determination unit, 53 recycled toner supply device,
54 New toner supply device

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/08 507 G03G 15/08 507D F term (reference) 2H030 AA04 AA06 AB02 AD03 AD16 BB23 BB38 BB42 BB52 BB63 2H077 AA12 AA37 AB02 AB13 AB14 AC02 AC16 AD06 AD13 AD31 BA08 DA10 DA43 DA63 DB02 DB14 GA01 GA13 2H134 GA01 GB02 JA11 KA40 KB11 KH01 KH17 KJ02

Claims (18)

[Claims] 1. A plurality of image bearing members, a charging and exposing unit for forming an electrostatic latent image on each of the image bearing members, and a toner image attached to the formed electrostatic latent images to form a visible image. In an image forming apparatus having an image forming apparatus having a developing unit for converting to toner, a transfer unit for transferring the attached toner to an intermediate transfer member, and a cleaning unit for removing the toner and the like attached to the image carrier after passing through the transfer unit. When transferring the second and subsequent colors to the body, the image forming apparatus has a path for returning the recycled toner collected and mixed by the cleaning means to each developing means and a path for supplying the new toner to each developing means. . 2. The image forming apparatus according to claim 1,
An image forming apparatus comprising: a mixing unit that mixes a new toner and a recycled toner mixed with each other before supplying the developing toner to the developing unit. 3. The image forming apparatus according to claim 2,
The image forming apparatus is characterized in that the means for mixing the new toner and the recycled toner mixed with the color has a sieve-shaped member. 4. The image forming apparatus according to claim 1,
An image forming apparatus comprising means for separately supplying new toner and recycled toner mixed in color to the developing means. 5. The image forming apparatus according to claim 1, further comprising: a color mixing ratio detection unit that detects a color mixing ratio of the recycled toner, and a new recycled toner based on a signal from the color mixing ratio detection unit. An image forming apparatus comprising: a toner supply amount determining means for determining a toner supply amount; and a supply device capable of varying the supply amounts of recycled toner and new toner according to the determination of the toner supply amount determining means. 6. The image forming apparatus according to claim 5, wherein the recycled toner color mixing ratio detection unit is a device that measures the reflection density of the recycled toner. 7. The image forming apparatus according to claim 5, wherein the recycled toner color mixture ratio detection unit is a calculation unit that calculates a color mixture ratio from an image signal. 8. The image forming apparatus according to claim 4, wherein:
An image forming apparatus characterized in that a ratio of supply of recycled toner and new toner to a developing unit is made constant. 9. The image forming apparatus according to claim 1, further comprising: a color mixing ratio detection unit that detects a color mixing ratio of toner in the developing unit; and a detection signal from the color mixing ratio detection unit. And a toner supply amount determining means for determining the supply amounts of the recycled toner and the new toner, and a supply device capable of varying the supply amounts of the recycled toner and the new toner according to the determination of the toner supply amount determining means. Image forming apparatus. 10. The image forming apparatus according to claim 9, wherein the color mixture ratio detecting unit for detecting the color mixture ratio in the developing unit is a device for measuring the reflection density on the developing sleeve included in the developing unit. . 11. An electrostatic latent image is formed by charging and exposing the surfaces of a plurality of image bearing members, and toner is attached to the electrostatic latent images to visualize the latent images. An image forming method for obtaining an image by forming a toner image on an intermediate transfer member by transferring the toner image onto an intermediate transfer member, and transferring the toner image onto a transfer paper.
In the case where the toner remaining on the image carrier and not transferred onto the intermediate transfer member is cleaned by the cleaning device provided in each image carrier, the order of transferring the toner onto the intermediate transfer member is the second and subsequent colors. Is an image forming method characterized by using both recycled toner and new toner collected by a cleaning device of each color for visualizing the electrostatic latent image. 12. The image forming method according to claim 11, wherein the recycled toner collected by the cleaning device and the new toner are mixed and then supplied to the developing device. 13. The image forming method according to claim 11, wherein the new toner and the recycled toner are supplied to the developing means through separate supply ports. 14. The image forming method according to claim 11, wherein the color mixture ratio of the recycled toner is detected, and the supply amount of the recycled toner and the new toner is determined based on the detected color mixture signal. An image forming method, which comprises determining and changing the supply amounts of recycled toner and new toner. 15. The image forming method according to claim 13, wherein when it is necessary to supply toner to the developing unit,
An image forming method characterized in that new toner and recycled toner are supplied to the developing means at a constant ratio. 16. The image forming method according to claim 11, wherein the color mixture ratio of the toner in the developing unit is detected, and the supply amount of the recycled toner is determined based on the detected color mixture ratio signal. An image forming method, characterized in that: 17. The toner color mixing ratio detection means according to claim 5, 6, 9, or 10 is a device for measuring the toner color mixing ratio, and the difference in spectral reflectance between color A and color mixing A + B is large. An image forming apparatus comprising: a light source that emits light of a wavelength and a light receiving unit that measures the intensity of light of the wavelength. 18. The method for detecting with a color mixing ratio detecting means according to claim 14, wherein the toner of color mixture A + B is irradiated with light having a wavelength having a large difference in spectral reflectance between color A and color mixture A + B, A toner color mixing ratio measuring method characterized in that the color mixing ratio is determined by measuring the intensity of reflected light with a light receiving unit and comparing the data with the reflectance data for colors A + B having a known color mixing ratio.