JP2001318566A - Electrophotographic image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent printing failure by appropriately detecting the life of a process cartridge and informing a user in a printer of a toner reuse-type. SOLUTION: In the toner reuse-type printer, the life of the process cartridge is detected by utilizing an initial toner quantity Wi, a pixel count value PC, a toner quantity Wdot that is consumed for 1 dot, the area of passed paper S, the quantity of impurity a which is mixed into a toner container per unit area of passed paper, a toner residue quantity W derived from transfer efficiency Tk and the two parameters of printed image quality. The printing failure is prevented by informing the user of the life.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electrophotographic image forming apparatus for forming an image on a recording medium, in which a toner cartridge using an electrophotographic process is detachably mountable. Here, the electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming method. Examples of the electrophotographic image forming apparatus include, for example, an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer, and the like).
It includes a facsimile machine and a word processor.

A process cartridge is a cartridge in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive drum are integrally formed as a cartridge, and this cartridge is made detachable from an image forming apparatus main body. In addition, at least one of the charging unit, the developing unit, and the cleaning unit and the electrophotographic photosensitive drum are integrally formed into a cartridge so that the cartridge can be attached to and detached from the image forming apparatus main body. Further, it means that at least the developing means and the electrophotographic photosensitive drum are integrally formed into a cartridge so as to be detachable from the apparatus main body.

[0003]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image forming process, an electrophotographic photosensitive member and a process means acting on the electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge is used for image forming. A process cartridge system detachable from the apparatus main body is employed. According to this process cartridge system, the maintenance of the apparatus can be performed by the user himself without relying on a serviceman, so that the operability can be remarkably improved. Therefore, this process cartridge system is widely used in image forming apparatuses.

A method of detecting the remaining amount of toner used in a printer can be roughly classified into two methods. The first method is
The remaining amount is detected by attaching a sensor to the toner cartridge and directly detecting the amount of toner.
The second method is to estimate the amount of used toner by counting the number of pixels written on the photosensitive drum at the time of printing and taking into account the amount of toner consumed per pixel. .

A typical method of the sensor method, which is the first method, is a method of installing an antenna inside a toner container. In FIG. 8, reference numeral 101 denotes a cartridge main body;
02 is a photosensitive drum, 103 is a toner container, 104 is a toner remaining amount detecting antenna, and 105 is a cleaner. A current flows through the antenna while the magnetic field generated by the magnetic toner is being detected by the antenna. When the toner is lost, no magnetic field is formed and the current stops flowing. This makes it possible to detect the remaining amount of toner. Since this sensor system directly measures the toner, high reliability can be obtained. However, if the amount of toner does not reach a predetermined state, it is not detected.

On the other hand, the second method is to count the number of pixels actually printed. In this method, the amount of toner per pixel used for printing is measured, and the number of printed pixels is counted to estimate the total amount of consumed toner and manage the remaining amount of toner. In this method, since the remaining amount of toner is continuously managed, it is possible to estimate not only a set point but also the amount of toner remaining continuously. However, since it will be based on when printing using a new cartridge,
When a different process cartridge is replaced, the count needs to be reset.

[0007]

There are two types of process cartridges, one with a cleaner and one without a cleaner.
In a system having a cleaner (cleaner system), all toner not used for transfer is removed by the cleaner, and new toner is used again for the next transfer. Until now, the detection of the remaining amount of toner is to directly or indirectly detect the amount of remaining toner in the toner container. This is very useful information.

On the other hand, a system without a cleaner (a cleanerless system,
FIG. 9) is expected from an environmental point of view because it has the advantage of not removing removed toner (unusable toner) which is a problem in the cleaner system. However, at present, the transfer efficiency is 100
%, The toner not used for transfer (defective toner having inferior magnetic properties) returns to the toner container without being removed and is mixed with unused toner. Further, since the paper powder of the paper used for printing and the chemicals adhering to the paper surface are also mixed into the toner container, the impurity concentration in the toner container increases. Because the impurity concentration causes a problem in print image quality, there are cases where it is better to replace the process cartridge even when the remaining amount of toner is sufficient.

SUMMARY OF THE INVENTION It is an object of the present invention to detect the life of a process cartridge using an amount of toner remaining and an impurity concentration in a toner container in an electrophotographic image forming apparatus in which a cleaner-less process cartridge is detachably attached to form an image on a recording medium. The present invention provides an electrophotographic image forming apparatus capable of notifying a user of a printing defect caused by an increase in the impurity concentration in a toner container in advance, thereby reducing the printing defect.

[0010]

According to a first aspect of the present invention, there is provided an electrophotographic image forming apparatus which detachably attaches a process cartridge and forms an image on a recording medium. Mounting means for removably mounting a process cartridge having an electrophotographic photosensitive drum and process means for operating the electrophotographic photosensitive drum, the process means reusing toner; a pixel count value; It has an arithmetic unit that calculates the impurity concentration from the toner consumption amount per dot of the count, the initial toner amount, the area of the paper to be passed, the amount of impurities mixed into the toner container per unit area of the paper, and the transfer efficiency. A process cartridge life detecting device capable of estimating the print quality from the impurity concentration and detecting the life of the process cartridge based on the remaining amount of toner and the print quality. It is.

In a cleanerless electrophotographic image forming apparatus, for example, a printer, the higher the printing density, the higher the impurity concentration, and the higher the printing defects such as hollow spots. This makes it impossible to achieve the printing quality desired by the user. There is a problem. For this reason, by detecting the impurity concentration in the toner container and estimating the print image quality based on the detected impurity concentration, the user is informed of whether or not printing is likely to occur. The remaining amount of toner and the impurity concentration in the toner container are calculated based on the initial toner amount, the pixel count value, the amount of toner consumed per pixel, the transfer efficiency, the area of the passed paper, and the unit area of the passed paper in the toner container. Can be determined from the amount of impurities mixed into the water. Therefore, the print quality is estimated from the obtained impurity concentration.
By giving a warning to the user with respect to the two parameters of the remaining toner amount and the print image quality, it is possible to prompt the user to replace the process cartridge in a state where the printing failure is likely to occur, thereby preventing the printing failure.

According to a second aspect of the present invention, the image forming apparatus has a memory for storing the impurity concentration in the process cartridge in the main body of the image forming apparatus. A storage unit for storing the concentration in the main body memory, and using the impurity concentration value at the time when the process cartridge is removed last time when the process cartridge to be used next is inserted is used as a life detection determination value of the process cartridge. An electrophotographic image forming apparatus according to the present invention.

The print quality required of the printer varies depending on the user. In some cases, the highest print quality is required for some people, or in some cases it is sufficient to print even if there is some printing failure. Further, the print image quality may change depending on the environment (temperature, humidity) where the system is placed and the type of paper used. In such a case, if the determination values (toner remaining amount and impurity concentration) for giving a warning for the remaining toner amount and the print image quality are fixed values (manufacturer recommended values), it is not possible to meet all the needs of the user. Therefore, the remaining toner amount and the impurity concentration at the time when the process cartridge is replaced are stored in the main body memory, and based on the information, a warning is issued to the user when the next process cartridge is in the state of the last replacement. In this way, by prompting the user to replace the process cartridge when the print image quality required by the user is obtained, the print image quality required by the user can be always achieved.

According to a third aspect of the present invention, the process cartridge has a memory for storing the amount of residual toner and the impurity concentration in the process cartridge. The impurity concentration is stored in the memory of the process cartridge, and when the process cartridge is inserted again into the image forming apparatus main body, the value is read on the image forming apparatus main body side,
The electrophotographic image forming apparatus according to the first aspect of the present invention, wherein the life detection determination of the process cartridge is started again using the remaining toner amount and the impurity concentration.

When detecting the remaining amount of toner and the concentration of impurities, if a process cartridge used in another image forming apparatus body is used, the history (the remaining toner amount and the amount of mixed impurities) up to that time cannot be determined, so that accurate detection is not possible. Detection cannot be performed. Therefore, the history up to that time is written in the process cartridge, and when used in another image forming apparatus main body, the history is read and used in the image forming apparatus main body. This makes it possible to perform accurate detection even when a process cartridge that has been used halfway is used in another image forming apparatus main body.

According to a fourth aspect of the present invention, a plurality of print image qualities are prepared, and the image forming apparatus has a device for changing the print image qualities in a main body. The user can set the print image qualities as necessary. According to the first aspect of the present invention, the determination value for detecting the life of the process cartridge is changed with respect to the changed print image quality, thereby determining whether the print image quality required by the user can be achieved. It is an electrophotographic image forming apparatus.

The print image quality required by the user is various, and it is impossible to meet those requirements with one judgment value. In addition, even when the normal image quality is normally sufficient, there are cases where a plurality of determination values are required, for example, the highest image quality is required. In such a case, a plurality of steps are provided for the print image quality, and the user can set the required print image quality to change the determination value and determine whether the print image quality required by the user can be achieved. In addition, when the image quality cannot be achieved, the replacement of the process cartridge is encouraged, so that the print image quality required by the user can be achieved.

According to a fifth aspect of the present invention, an image forming apparatus main body detects an impurity concentration in a process cartridge,
It has a device that can change the laser output for writing a latent image on the electrophotographic photosensitive drum and the transfer bias according to the value, and usually changes the process conditions according to the impurity concentration in the process cartridge, so that printing is usually performed. The electrophotographic image forming apparatus according to the first aspect of the present invention is characterized in that it is possible to prevent a printing failure even at an impurity concentration that causes a failure, and to reduce the printing failure.

In the cleanerless system, the impurity concentration increases each time printing is performed, and the print quality gradually decreases. This is because when the impurity concentration increases, the magnetic characteristics in the toner container decrease due to the influence of the impurity concentration. For this reason, the amount of toner on the electrophotographic photosensitive drum decreases, and the transfer efficiency when the toner on the electrophotographic photosensitive drum is transferred to paper also decreases. However, in any case, the deterioration of the magnetic characteristics can be compensated for by changing the output of the laser for writing the latent image on the electrophotographic photosensitive drum or the bias voltage applied at the time of transfer, and the rate of printing defects is reduced. be able to.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] In a first embodiment, a cleanerless printer detects the remaining amount of toner and the impurity concentration in a process cartridge and informs the user of the detected amount. It is possible to reduce the printing failure which causes.

FIG. 9 shows the basic configuration of the process cartridge used in this example. Reference numeral 101 denotes a cartridge body (the same reference numerals are used for the entire process cartridge).
Reference numeral 02 denotes a photosensitive drum, and reference numeral 103 denotes a toner container. A device for counting the number of pixels used for printing is installed on the image forming apparatus main body side where the process cartridge is detachable. The impurity concentration in the toner container 103 can be calculated from the pixel count value, the transfer efficiency, the initial toner amount, the area of the paper passed, and the impurity amount mixed into the toner container per unit area of the paper passing (calculation). The formula will be described later). FIG. 1 shows a series of flows according to this configuration.

In a cleanerless printer, toner not used for transfer returns to the toner container. This toner is not transferred even when a high voltage transfer bias is applied between the photosensitive drum 102 and the paper, and is a defective toner (impurity) having poor magnetic properties. Also, during paper passing, paper bias from paper and chemicals adhering to the paper surface adhere to the photosensitive drum 102 due to the transfer bias,
It also enters the toner container 103 and becomes an impurity. The magnetic properties in the toner container 103 are degraded by these impurities, so that the amount of toner on the photosensitive drum is reduced, and the transfer efficiency is also lowered, so that printing defects are likely to occur.

The amount of toner consumed by printing and the amount of toner returning to the toner container 103 (the amount of loose toner) can be obtained from the transfer efficiency and the pixel count (the second term and (2) in the following equation (1)). Clause 1). Further, the amount of impurities caused by the paper is obtained from the area through which the paper has passed and the amount of impurities adhering to the photosensitive drum 102 from the paper and mixed into the toner container 103 per unit area of the paper (the second term of the following equation (2)) . The area of the passed paper can be obtained, for example, from the paper size detection attached to the paper feed cassette and the time during which the leading edge detection sensor in front of the registration roller falls. For the amount of impurities adhering from the paper to the photosensitive drum 102 and mixed into the toner container 103 per unit area of paper passing, a standard value is checked in advance and used. The impurity concentration is calculated using these pieces of information. The calculation formula is shown below. Where P
u: impurity concentration, Wi: initial toner amount, Wdot: toner consumption amount per dot, PC: pixel count number, Tk: transfer efficiency, U: impurity amount in the toner container,
u: the amount of impurities per unit area of paper; n: the number of papers passed; S: the area of paper passed; W: the remaining amount of toner.

W = Wi− (PC × Wdot × Tk) (1) U = {PC × Wdot × (1−Tk)} + (n × S × u) (2) Pu = U / W (3) The print quality is estimated from the values, and when the print quality reaches a certain reference value (manufacturer recommended value), a warning is issued to the user to urge the user to replace the process cartridge.

FIG. 2 schematically shows changes in the remaining amount of toner and print image quality.
Shown in FIG. 2A illustrates a change in the remaining toner amount W, in which the vertical axis represents the remaining toner amount W, and the horizontal axis represents the pixel count value P.
C. The remaining toner amount W decreases linearly as the pixel count value PC increases (the number of prints increases). When the remaining amount of toner becomes lower than a certain value, a notice of no toner is given. FIG. 2B shows a change in print image quality. The vertical axis represents print image quality, and the horizontal axis represents impurity concentration Pu. As the impurity concentration in the toner container increases, the print quality deteriorates. However, the manner in which the print quality deteriorates is not linear with respect to the impurity concentration Pu, but deteriorates rapidly when the impurity concentration Pu increases to some extent. When the print image quality deteriorates to some extent, a warning of print image quality deterioration is issued. Of the remaining toner amount W and the print image quality, a warning is given to the one that has reached the reference value first, thereby prompting the user to replace the process cartridge.

Referring to FIG. 1, the flow of the process cartridge 101 mounted on the main body of the image forming apparatus for use and replacement will be described. When the toner remaining amount detection is started (S0), the arithmetic unit of the image forming apparatus main body performs the following arithmetic. Step S
1 using the pixel count value PC at the time of image formation, and the toner remaining amount W and the toner container 1 by the equations (1), (2), and (3).
03, the impurity amount U and the impurity concentration Pu are obtained (step S2). In step 3, the remaining toner amount W is compared with a predetermined reference value. If the remaining toner amount W is smaller than the reference value, the process proceeds to step 4. Then, a warning is issued to the image forming apparatus main body that there is no toner. Therefore, the user operates the process cartridge 101.
(CRG in FIG. 1; the same applies to the following flow charts.) (Step 5).

On the other hand, if the remaining toner amount W is larger than the reference value in step 2, the process proceeds to step S6. If the impurity concentration Pu is smaller than the predetermined reference value, the process returns to step 1 and the image formation is continued. . If the impurity concentration Pu is higher than the reference value in step 6, the process proceeds to step 7, and a print quality deterioration warning is displayed on the image forming apparatus main body. Then, the process cartridge is replaced (step 5).

[Second Embodiment] In the second embodiment, in addition to the first embodiment, when detecting the remaining amount of toner and the impurity concentration Pu, the impurities when the user replaces the process cartridge 101 are detected. The density Pu and the individual identification number of the process cartridge 101 are stored in the memory of the image forming apparatus main body. If the next inserted process cartridge 101 is the same as the previous one, the determination value is not changed. If the process cartridge 101 is new, a print failure of the next process cartridge 101 occurs based on information at the time of replacement. Is changed to a manufacturer recommended value (initial value) when a warning is issued, and a warning is issued based on the determined value to maintain the print image quality required by the user.

The basic configuration of the process cartridge 101 used in this embodiment is the same as that of the first embodiment (FIG. 9). Further, a memory for storing the impurity concentration Pu and the individual identification number of the process cartridge 101 when the process cartridge 101 is replaced is mounted on the image forming apparatus main body side. Based on the information, it is possible to change the determination value for issuing a warning prompting the replacement of the process cartridge. FIG. 3 shows the flow of this example. In FIG. 3, steps S1 to S5 and S1 to S3 to S7 are the same as in the first embodiment, and the reference values of the remaining toner amount W and the impurity concentration Pu are corrected for the following reasons.

The criterion for determining the print quality differs depending on the user. For example, if a certain determination value is specified as a manufacturer's recommended value, a person who replaces the process cartridge 101 before the determination value, or conversely, even if a warning of poor printing is given by the determination value, the process cartridge 101 is replaced. Some people do not. This is because the user's requirements differ for the printer.If high print quality is required, replace the printer before the judgment value.If you want to print more sheets than the print quality, do not replace it even if warned It turns out that.

The print quality may vary depending on the environment (temperature and humidity) where the printer is placed and the type of paper used. Depending on the temperature and humidity, the photosensitive drum 10
2 and the transfer efficiency are different, and the amount of the loose toner (defective toner) changes, so that the impurity concentration Pu changes. In addition, depending on the type of paper used, there are papers on which paper dust easily emerges and papers on which paper dust hardly emerges, so that the impurity concentration Pu also changes. For this reason, when the determination value is fixed, a deviation occurs compared to the actual print image quality.

In order to make these corrections, the judgment value is made variable rather than fixed. When the process cartridge is replaced, the impurity concentration Pu at that time and the individual identification number of the process cartridge 101 are written in the memory of the image forming apparatus main body, and the determination is made using the information when the next process cartridge 101 is used. Change the value. When the judgment value is changed by this method, the judgment value can be determined based on the print image quality required by the user, and at the same time, the judgment value is determined in consideration of the influence of the environment where the printer is placed and the type of paper used. can do. As a result, the print image quality desired by the user can be achieved, and the deviation of the determination value due to the change in the impurity concentration Pu can be corrected.

At this time, a problem is that when the process cartridge 101 is temporarily removed from the main body of the image forming apparatus due to, for example, a paper jam, the process cartridge information at that time is written into the memory of the main body of the image forming apparatus. It is. In order to prevent this, when replacing the process cartridge in step S8 of FIG. 3, it is determined whether the next inserted process cartridge 101 is the previous process cartridge 101 or a new process cartridge 101. This judgment is made for process cartridge 1
When the process cartridge 101 is removed from the image forming apparatus main body, the individual identification number of the process cartridge 101 is stored in the memory of the image forming apparatus main body.
When 1 is inserted into the image forming apparatus main body, the individual can be identified by referring to the individual identification number. If the replaced process cartridge 101 in step S8 is the same as the previous process cartridge 101, the process returns to step S1. If the process cartridge 101 replaced in step 8 is not the same as the previous one, then step 9
To the memory of the image forming apparatus main body (main body memory), and the impurity concentration P after the process cartridge replacement.
The reference value of u is set to a reference value 2, and the reference value of the remaining amount of toner is set to a reference value 1.

[Third Embodiment] In the third embodiment, in addition to the second embodiment, a memory mounted on the process cartridge 101 is used and the process cartridge 10 is stored there.
The use history (toner remaining amount W, impurity concentration Pu) is stored and read and used when used in another image forming apparatus main body. As a result, even when the process cartridge 101 used halfway is used in another image forming apparatus main body, the remaining toner amount W and the mixed impurity concentration Pu of the process cartridge 101 can be taken over accurately.
This enables accurate detection even when the process cartridge 101 being used is used.

The basic structure used in this example is the same as that of the first embodiment (see FIG. 9).
1 is equipped with a memory for storing a usage history. When the process cartridge 101 is removed from the image forming apparatus main body, the remaining toner amount W and the impurity concentration Pu at that time are stored in a memory mounted on the process cartridge 101. When the process cartridge 101 is inserted into the image forming apparatus main body, a device for reading information from a memory mounted on the process cartridge 101 is mounted on the image forming apparatus main body side. By reading the history information, the life detection of the process cartridge 101 can be restarted. FIG. 4 shows the flow of this example.

When the process cartridge 101 is used while being inserted into another image forming apparatus main body during use, or when the process cartridge 101 is temporarily pulled out of the image forming apparatus main body due to a paper jam or the like, the process cartridge 101 is reinserted and used. And so on. In these cases, if the process cartridge 101 is removed from the image forming apparatus main body, the information such as the remaining toner amount and the concentration of mixed impurities is reset, so that it is impossible to accurately detect the remaining toner amount. As means for solving these problems, a memory is mounted on the process cartridge 101 to store information on the use history of the process cartridge 101 (remaining toner amount W, mixed impurity concentration Pu). Thus, when the process cartridge 101 is once withdrawn from the main body of the image forming apparatus, reinserted, and used, the usage history information is read by the main body of the image forming apparatus, and the remaining toner amount W is used by using the information.
And the impurity concentration Pu can be detected, and it is possible to cope with the case where the image forming apparatus is inserted into another image forming apparatus main body during use or is temporarily removed from the image forming apparatus main body due to a paper jam or the like.

The difference between the flowchart of FIG. 4 and FIG.
Step S2 is provided after step S2, and step S2
Is stored in a memory mounted on the process cartridge 101. Steps S3 to S5 and S3 to S6 to S7 are the same as those in the second embodiment. When the process cartridge 101 is removed from the image forming apparatus main body in step 5, the remaining toner amount W and the impurity concentration Pu at that time are stored in the memory mounted on the process cartridge 101. Next, when the process cartridge 101 is mounted on the main body of the image forming apparatus (Step 8), the main body of the image forming apparatus reads the remaining toner amount W and the impurity concentration P from the memory mounted on the process cartridge.
u, and the initial states of the remaining toner amount W and the impurity concentration Pu are changed to the reference value 2 respectively.

[Fourth Embodiment] In the fourth embodiment, in addition to the third embodiment, a step is provided for the print image quality so that the user can change the setting to the required print image quality. The determination is made based on the set print quality, and the user is notified whether the print quality can be achieved.

The basic configuration of the process cartridge 101 used in this embodiment is the same as that of the first embodiment (see FIG. 9), but a device for changing the set value of the print image quality (for example, adjustment) in the image forming apparatus main body. Knob) is mounted. By moving the knob, the print image quality is changed, and it is determined whether the image quality can be achieved. FIG. 5 shows the flow of this example, and FIG. 6 shows a display example in which the print quality is graded.

The printing quality required by the user is various. For example, there are cases where printing must always be performed at the highest image quality. In such a case, the set value of the print image quality is divided into several steps, and the set value can be freely set by the user. If the highest image quality is always required, the set value is set to the highest image quality. If the highest image quality cannot be achieved due to an increase in the impurity concentration Pu or the like, a warning of print image quality deterioration is issued at that point. At this time, if the set value of the print image quality is lowered, the warning of the print image quality deterioration disappears, and printing at the highest image quality cannot be performed, but printing at a stage where the print image quality is inferior becomes possible.

Further, even if the highest image quality is not normally required, a document requiring the highest image quality may have to be printed in some cases. In such a case, the normal image quality is usually set, and when the highest image quality is required, the print image quality is set to the highest image quality. If the printing of the highest image quality is possible at the set time, a warning of deterioration of the printing image quality is not issued, and if the impurity concentration is high and the highest image quality cannot be achieved, a warning of the deterioration of the printing image quality is issued. If you are warned that the print quality has degraded,
By exchanging the process cartridge 101, printing with the highest image quality becomes possible. Also, even if a warning is issued when the highest image quality is set, printing can be continued by lowering the print image quality.

The flowchart of FIG. 5 differs from that of FIG. 1 in that, after the system is started, first, a reference value 2 is set in step S1-1. If a warning of no toner is issued in step 4 or a warning of deterioration of print image quality is issued in step 7, the process proceeds to step S5.
The process proceeds to -1, and it is determined whether or not the set value has been changed to a print image quality other than the normal image quality (normal). If the set value is the normal image quality, the process proceeds to step S5, where the process cartridge is replaced. Returns to step S1-1 because the image quality can be reduced and the print quality can be set. In FIG. 6, the print image quality is normal for normal image quality, fine for fine image quality, and super fine for image quality.
Indicates ultra-fine image quality, and ultra superfine indicates ultra-fine image quality.

[Fifth Embodiment] In the fifth embodiment, when the remaining toner amount W and the impurity concentration Pu are detected, the process conditions on the image forming apparatus main body side are changed to increase the impurity concentration Pu. Originally, even in a state where a printing failure occurs, more printing can be performed without causing a printing failure.

Process cartridge 10 used in this example
1 is the same as that of the first embodiment (see FIG. 9).
However, an apparatus capable of changing process conditions (output of a laser for writing a latent image on the photosensitive drum 102, transfer bias) depending on the state of the process cartridge 101 (impurity concentration Pu) is mounted on the image forming apparatus main body. FIG. 7 shows the flow of this example.

In the cleanerless system, the impurity concentration increases each time printing is performed, and the print quality gradually deteriorates. In consideration of this, the process conditions are changed as the impurity concentration Pu increases. If the impurity concentration Pu increases, the magnetic properties in the toner deteriorate, and the amount of toner on the photosensitive drum 102 decreases. Therefore, the output of a laser for writing a latent image on the photosensitive drum 102 is increased. By doing so, the toner can be sufficiently adhered to the photosensitive drum 102 even in a state where the magnetic characteristics are deteriorated, and the probability of occurrence of printing failure can be reduced. When the magnetic properties of the toner decrease, the photosensitive drum 1
When the toner on the sheet No. 02 is transferred to paper, the transfer efficiency is deteriorated. In this case, the transfer bias voltage between the photosensitive drum 102 and the paper is increased. By doing so, it is possible to increase the transfer efficiency even with toner having poor magnetic properties, and it is possible to reduce the probability of occurrence of printing defects.

By changing the process conditions as described above, the occurrence of printing defects can be reduced even in a state where the concentration of impurities is originally high and printing defects are likely to occur.
More printing is possible.

The difference between the flowchart of FIG. 7 and FIG. 1 is that
In step S4, if the process conditions can be changed even if there is a toner absence warning or a print image quality deterioration warning, the process conditions are changed, and in step 4, the reference value of the impurity concentration Pu is further changed to the reference value 2, and step 1 is performed. And the image formation is continued. If there is no possibility that the process conditions will be changed in step S4, the process proceeds to step 5, and the process cartridge 101 is replaced.

[0048]

As described above, according to the first invention of the present application, the user can detect the impurity concentration in the toner container in addition to the remaining amount of toner in the process cartridge in the cleanerless printer. Can give a warning about the print quality, thereby making it possible to prevent printing defects before they occur.

According to the second invention of the present application, the impurity concentration detected with respect to the first invention is stored in the memory of the image forming apparatus main body when the process cartridge is replaced, and when the new process cartridge is inserted. By using the value as a determination value for detecting the life of the process cartridge, it is possible to determine the detection of the life of the process cartridge based on the print quality required by the user.

According to the third aspect of the present invention, the remaining amount of toner and the impurity concentration detected with respect to the second aspect are stored in the memory of the process cartridge, and the process cartridge is once removed from the image forming apparatus main body. When the data is extracted and reinserted, the data is read on the main body side, and it is possible to restart the life detection based on the remaining amount of toner and the impurity concentration of the process cartridge.

According to the fourth aspect of the present invention, the user can freely set the print image quality by providing a plurality of stages for the print image quality to determine whether the print image quality desired by the user can be achieved. This makes it possible to make a judgment, thereby making it possible to prevent printing defects.

According to the fifth aspect of the present invention, by changing the process conditions according to the impurity concentration in the toner container, printing can be performed even at the impurity concentration which should otherwise be a printing defect, thereby reducing printing defects. Enabled.

[Brief description of the drawings]

FIG. 1 is a flowchart according to the first embodiment.

FIGS. 2A and 2B are diagrams showing changes in (a) remaining amount of toner and (b) print image quality in the first embodiment.

FIG. 3 is a flowchart in the second embodiment.

FIG. 4 is a flowchart in the third embodiment.

FIG. 5 is a flowchart in the fourth embodiment.

FIG. 6 is a diagram relating to a print image quality display method according to a fourth embodiment.

FIG. 7 is a flowchart in the fifth embodiment.

FIG. 8 is a schematic diagram illustrating a conventional example (cleaner system).

FIG. 9 is a schematic diagram illustrating a conventional example (cleanerless system).

[Explanation of symbols]

 101: cartridge body (process cartridge) 102: photoreceptor drum 103: toner container 104: remaining amount detecting antenna 105: cleaner

Continued on front page F term (reference) 2H027 DA44 DA45 DC10 DD02 DE07 EA02 EA03 EB02 EC06 EC09 EC18 EC20 FA30 FB15 HB02 HB05 HB15 HB17 2H071 BA33 BA34 DA08 DA15 2H077 AA37 AC16 DA15 DA20 DA24 DA32 DA78 GA04

Claims (5)

[Claims] 1. An electrophotographic image forming apparatus which detachably attaches a process cartridge and forms an image on a recording medium, comprising: a. A mounting means for removably mounting a process cartridge comprising: an electrophotographic photosensitive drum; a process means acting on the electrophotographic photosensitive drum, the process means reusing toner; and a pixel count value, a pixel. Toner consumption per dot of count, initial toner amount, area of paper to be passed,
It has an arithmetic unit that calculates the impurity concentration from the amount of impurities mixed into the toner container per unit area of paper passing and the transfer efficiency, and further estimates the printing quality from the impurity concentration, and uses the remaining amount of toner and the printing quality to process cartridges. An electrophotographic image forming apparatus comprising: a process cartridge life detecting device capable of detecting the life of the process cartridge. And a memory for storing the impurity concentration in the process cartridge in the image forming apparatus main body.
When the process cartridge is removed from the image forming apparatus main body, the impurity concentration at that time is stored in the main body memory, and when the process cartridge to be used next is inserted, the impurity concentration value at the time when the previous process cartridge was removed is stored in the process cartridge. The electrophotographic image forming apparatus according to claim 1, wherein the electrophotographic image forming apparatus is used for a life detection determination value of the image. 3. The process cartridge has a memory for storing the remaining toner amount and the impurity concentration in the process cartridge, and when extracting from the process cartridge, the remaining toner amount and the impurity concentration at that time. When the process cartridge is inserted again into the image forming apparatus main body, the value is read on the image forming apparatus main body side, and the life detection determination of the process cartridge is started again using the remaining toner amount and the impurity concentration. The electrophotographic image forming apparatus according to claim 1, wherein: 4. An apparatus for preparing a plurality of print qualities, having a device for changing the print qualities in the image forming apparatus main body, enabling a user to set the print qualities as needed, 2. The method according to claim 1, wherein the determination value for detecting the life of the process cartridge is changed to determine whether the print quality desired by the user can be achieved.
2. The electrophotographic image forming apparatus according to 1. 5. An image forming apparatus main body side detects an impurity concentration in a process cartridge, and outputs a laser output for writing a latent image on an electrophotographic photosensitive drum based on the detected impurity concentration.
It has a device that can change the transfer bias, and by changing those process conditions according to the impurity concentration in the process cartridge, it is possible to prevent printing failure even if the impurity concentration normally causes printing failure. 2. The electrophotographic image forming apparatus according to claim 1, wherein printing defects are reduced.