JPH09160367A - Residual toner detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To classify residual toner amounts into plural stages and to precisely discriminate the residual toner amounts. SOLUTION: A toner sensor 21 detects a change in permeability changed by the rotation of an agitator 37 stirring magnetic toner. A permeability change pattern is previously stored for various residual toner amounts and the pattern of the detected change in the permeability is collated with the stored pattern, to classify the residual toner amounts into the plural stages and recognize the residual toner amounts. Since the pattern of the change in the permeability by the rotation of the agitator 37 is different according to the residual toner amount, it can be discriminated by the collation of the pattern. Further, the residual amount is discriminated by the permeability actually measured by the sensor, so that detecting accuracy is made high.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner remaining amount detecting device for detecting a remaining amount of toner used in a recording device such as a laser printer or a copying machine, and more particularly to a remaining toner amount for detecting a remaining amount of magnetic toner. Regarding a detection device.

[0002]

2. Description of the Related Art In a recording apparatus such as a laser printer or a copying machine using an electrophotographic system, toner is attached to a portion of an electrostatic latent image formed on a photoconductor to develop the latent image. ing. Toner used for development is generally stored in a toner tank and conveyed toward a developing device by a supply / agitation member such as an agitator. Each time printing or copying is performed, the toner in the toner tank is gradually consumed and the remaining amount decreases, so when the remaining amount of toner is detected and the toner in the tank is reduced to a certain amount, the user can Is being warned.

As a device for detecting the remaining amount of toner, there is one that actually detects the remaining amount of toner in the tank by using a sensor such as a piezoelectric vibrator, a magnetic permeability sensor and a photo sensor. For example, in the case of using a piezoelectric vibrator, the sensor is provided in the toner tank near the bottom of the tank. Then, the remaining amount of toner is determined by detecting the weight of toner applied to the piezoelectric vibrator. There is also a method of calculating the toner consumption amount from the number of printed sheets and calculating the remaining amount. Further, in the one in which a latent image is formed on the photoconductor by turning on the laser light in dot units corresponding to image information, the number of times the laser light is turned on, that is, the number of dots formed on the photoconductor is counted and the toner is counted. There is a method in which the consumption amount of is calculated and the remaining amount is calculated from this.

In addition, Japanese Patent Laid-Open No. 3-77978 discloses a toner remaining amount detecting device using a magnetic permeability sensor. In this apparatus, the magnitude of the magnetic field formed by the magnetic toner is measured from the outside of the toner tank by a magnetic permeability sensor arranged in pressure contact with the bottom of the tank. When the amount of toner accumulated at the bottom of the tank becomes small, the detected magnetic field becomes weak, and the remaining toner amount warning is given when the amount becomes less than a predetermined threshold value. In addition, JP-A-3-17673
Japanese Patent Publication discloses a toner remaining amount detecting device using a photo sensor. In this apparatus, the toner tank is formed of a transparent member that is difficult to be charged, and the remaining amount is detected by irradiating light from the outside of the tank and whether the light is blocked by the toner.

In Japanese Unexamined Patent Publication No. 3-59681, a sensor detects that the remaining amount is low to some extent, the consumption amount after that is obtained based on the number of printed sheets, and the printing operation is performed after the prescribed number of sheets is reached. A device for inhibiting is disclosed. Further, in JP-A-2-39178 and JP-A-3-58854, the number of black dots formed on the photosensitive member is counted based on the print data, and the consumption amount per dot and the printed black There is disclosed a printer device that obtains a toner consumption amount from the total number of dots and warns the remaining amount.

[0006]

In the apparatus for detecting the actual remaining amount of toner by using the piezoelectric vibrator, the magnetic permeability sensor, the photo sensor, etc. described above, the output of the sensor is compared with a predetermined threshold value. Therefore, it is possible to detect only two states of whether or not the remaining amount of toner is equal to or more than the amount corresponding to the threshold value. In a storage device that issues a toner remaining amount warning using such a sensor, normally only a warning that the toner is empty is issued. For this reason, there is a problem that it is often necessary to replenish toner or replace the toner cartridge during printing. In addition, if there is no inventory of replenishment toner or toner cartridge when the warning is issued, there is a problem that the work is interrupted for a long period of time before obtaining them.

In an apparatus that counts the number of prints or calculates the toner consumption amount from the total number of black dots to be printed to obtain the remaining amount, the remaining amount of toner can be continuously recognized. A warning can be issued when the remaining amount is reached. However, the amount of toner consumed per sheet and the amount of toner consumed per dot differ depending on the image to be printed, so the remaining amount of toner cannot be accurately obtained. Further, if the toner is replenished on the way, there is a problem that the remaining amount of the toner cannot be recognized thereafter. Furthermore, the remaining amount detecting device that obtains the remaining amount based on the total number of dots cannot be applied to a copying machine of a type that directly forms a latent image on a photoconductor by reflected light from a document.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a toner remaining amount detecting device capable of discriminating the remaining amount of toner in a plurality of stages.

[0009]

According to another aspect of the present invention, there is provided a toner accommodating means for accommodating a magnetic toner, a toner agitating means for agitating the magnetic toner accommodated in the toner accommodating means, and a toner accommodating means. The magnetic field detection means for detecting the magnitude of the magnetic field produced by the magnetic toner at a predetermined position, and the pattern of the change in the magnitude of the magnetic field detected by the magnetic field detection means when the toner stirring means are stirring The magnetic field change pattern storage means stored in association with the remaining amount of the magnetic toner stored in the toner storage means and the magnitude of the magnetic field detected by the magnetic field detection means when the toner stirring means is stirring the magnetic toner. Collating means for collating the variation pattern with the pattern stored in the magnetic field variation pattern storage means, and the magnetic toner in the toner containing means based on the collation result of the collating means. And a toner remaining amount determining means for determining the remaining amount is provided in the toner residual amount detection device.

That is, according to the first aspect of the present invention, the pattern in which the magnitude of the magnetic field changes at a predetermined position according to the stirring by the toner stirring means is stored in advance in association with the remaining amount of toner. Since the pattern differs depending on the remaining amount of toner, the remaining amount of toner is determined by collating the pattern of change in the magnetic field detected by the magnetic field detection means with the previously stored pattern.

According to the second aspect of the invention, the toner containing means for containing the magnetic toner, the toner agitating means for agitating the magnetic toner contained in the toner containing means, and the magnetic toner contained in the toner containing means are produced. Magnetic field detecting means for detecting the magnitude of the magnetic field at a predetermined position, binarizing means for binarizing the magnitude of the magnetic field detected by the magnetic field detecting means with a predetermined threshold as a reference, and toner stirring The remaining amount of the magnetic toner accommodated in the toner accommodating means is the sum total time when the output value of the binarizing means when the means is stirring the magnetic toner becomes one of the predetermined values within a certain time. And the magnetic field change pattern storage means stored in association with the magnetic field change pattern storage means, and the total sum of the times when the output value of the binarization means becomes one of the fixed values while the toner stirring means is stirring the magnetic toner. Time The measuring means, the comparing means for comparing the time obtained by the total time measuring means with the time stored in the magnetic field change pattern storing means, and the magnetic toner in the toner containing means based on the comparison result of the comparing means. The remaining toner amount detecting device is equipped with a remaining toner amount determining means for determining the remaining amount.

That is, according to the second aspect of the present invention, the sum of the times when the value obtained by binarizing the magnitude of the detected magnetic field based on a predetermined threshold value takes one of the values within a certain time It is stored in advance in association with the remaining amount of toner. For example,
The total sum of the times during which the threshold value is equal to or less than the threshold value is stored in advance for various remaining toner amounts. The total sum of the times below the threshold differs depending on the remaining amount of toner. Therefore, by measuring the total amount of time that the magnitude of the magnetic field at a predetermined position is below a threshold value within a certain time while the toner is being stirred, and comparing it with the previously stored time, The remaining amount of is being determined.

According to the third aspect of the invention, the toner containing means for containing the magnetic toner, the toner agitating means for agitating the magnetic toner contained in the toner containing means, and the magnetic toner contained in the toner containing means are produced. Magnetic field detecting means for detecting the magnitude of the magnetic field at a predetermined position, binarizing means for binarizing the magnitude of the magnetic field detected by the magnetic field detecting means with a predetermined threshold as a reference, and toner stirring The length of time during which the output value of the binarizing means continuously reaches one of the predetermined values while the means is stirring the magnetic toner is the remaining amount of the magnetic toner stored in the toner storing means. Continuous time for measuring the length of time during which the output value of the binarizing means continuously becomes one value while the magnetic stirring pattern is stored in association with the magnetic field change pattern storing means and the toner stirring means is stirring the magnetic toner. Measuring means, Comparing means for comparing the length of time obtained by the continuous time measuring means with the length of time stored in the magnetic field change pattern storing means, and the magnetic toner in the toner containing means based on the comparison result of the comparing means. The remaining toner amount detecting device is equipped with a remaining toner amount determining means for determining the remaining amount.

That is, according to the third aspect of the present invention, the remaining amount of toner is the time for which the value obtained by binarizing the magnitude of the detected magnetic field on the basis of a predetermined threshold continuously takes one value. It is stored in advance in association with. For example, the time during which the threshold value is continuously decreased below the threshold value is stored in advance for various remaining toner amounts. The continuous time to be equal to or less than the threshold depends on the remaining amount of toner. Therefore, the time when the magnitude of the magnetic field at a predetermined position continuously becomes a value equal to or less than the threshold value while the toner is being stirred is measured and compared with the time stored in advance to determine the toner The remaining amount is determined.

According to a fourth aspect of the present invention, there are provided a toner containing means for containing the magnetic toner, a toner agitating means for agitating the magnetic toner contained in the toner containing means, and a magnetic toner agitated by the toner agitating means. Magnetic field detecting means for detecting the magnitude of the magnetic field to be produced at a predetermined position, binarizing means for binarizing the magnitude of the magnetic field detected by the magnetic field detecting means based on a predetermined threshold value, and toner The number of times the output value of the binarizing means when the agitating means is agitating the magnetic toner becomes one of the predetermined values within a fixed time is defined as the remaining amount of the magnetic toner accommodated in the toner accommodating means. Magnetic field change pattern storage means stored in association with each other,
Counting means for counting the number of times that the output value of the binarizing means has become one of the values within a fixed time while the toner stirring means is stirring magnetic toner, and a history of the number of times counted by this counting means is stored. History storage means, comparison means for comparing the number of times counted by the counting means with the number of times stored in the magnetic field change pattern storage means, and a history of the comparison result of this comparison means and the number of times stored in the history storage means. The remaining toner amount detection device is provided with a remaining toner amount determination unit that determines the remaining amount of magnetic toner in the toner storage unit based on the above.

That is, according to the invention of claim 4, the value after binarizing the magnitude of the magnetic field detected at a certain position with a predetermined threshold value as a reference is one of the values within a certain period of time. The number of times of taking is stored in advance in association with the remaining amount of toner.
For example, the number of times the threshold value is equal to or less than a threshold value is stored in advance for various remaining toner amounts. The number of times may become almost the same value in the process of decreasing the remaining amount of toner. Therefore, the history of the number of times of measurement is stored, and the remaining amount of toner is discriminated based on the comparison result of the number of times stored in advance, the comparison result of the number of times measured this time, and the history of the number of times stored.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the configuration of a laser printer using a toner remaining amount detecting device according to an embodiment of the present invention. A process cartridge 12 containing various devices for performing a series of image forming processes, such as a toner tank, a photoconductor, and a developing device, is provided in a substantially central portion of a main body 11 of the laser printer. The process cartridge 12 can be attached to and detached from the main body 11, and when the toner runs low, the process cartridge 1
It is designed to be replaced every 2 times, which facilitates maintenance. On one side of the process cartridge 12,
A slit (not shown) for entering a laser beam for exposing the photoconductor is provided. A laser optical system 13 that modulates and deflects laser light according to a recorded image is arranged on the side where the slit is provided.

A fixing device 14 for fixing the toner image formed on the recording paper is provided on the opposite side of the process cartridge 12 from the laser optical system. The fixing device 14 is a stacker unit 1 provided on the upper surface of the main body 11.
5 is provided with a discharge port 16 for discharging the recording paper. At the bottom of the main body 11, a paper storage unit 17 for accommodating a plurality of recording papers in a stack is provided. A half-moon roll 18 is arranged near one end of the sheet storage unit 17 to feed the recording sheets from the sheet storage unit 17 to the transport path one by one. A transport path for transporting the recording paper delivered by the half-moon roll 18 to the fixing device 14 via the vicinity of the process cartridge 12 is formed by a paper chute 19 in which the transport roll and the paper guide are integrated.

A toner sensor 21 for detecting the remaining amount of toner is provided near the bottom of the process cartridge 12. The toner sensor 21 is configured to press the bottom portion of the process cartridge 12 from outside with a predetermined pressure when the process cartridge 12 is set in the main body 11. The toner used in this laser printer is magnetic toner, and the toner sensor 21 detects the magnetic permeability of the magnetic field produced by the magnetic toner at a predetermined position. Between the laser optical system 13 and the paper storage unit 17, a circuit that controls the operation of the laser printer and a circuit unit 22 including a power supply unit are provided.

FIG. 2 shows the process cartridge and the toner sensor shown in FIG. 1 in more detail. An opening is provided on one side wall of the process cartridge 12, and about one third of the circumference of the photosensitive drum 31 is exposed through the opening.
It is arranged to be exposed to the outside. A toner tank 32 for accommodating toner is provided in a portion of the process cartridge 12 which is a lower side when set in the main body 11.
Is provided. The developing roller 33 that develops the electrostatic latent image formed on the photosensitive drum 31 is provided in the toner tank 32.
And the photosensitive drum 31. Around the photosensitive drum 31, a charging roll 34 for uniformly charging the photosensitive drum 31 and a cleaning blade 35 for agitating the toner remaining on the photosensitive drum 31 without being transferred are provided.

In the toner tank 32, an arrow 3 in the figure is shown.
There is provided a plate-shaped agitator 37 which is rotated in the direction indicated by 6 and which stirs the contained toner and conveys the toner toward the developing roll 33, the cross section of which is "V". The agitator 37 includes a photosensitive drum 31.
The driving force of a main motor (not shown) for rotating the motor is transmitted by various gears (not shown). This allows the agitator 37 to rotate at a constant speed according to the rotation of the main motor. Toner sensor 21
Is attached to the other end of the compression spring 38 whose one end is fixed to a predetermined position of the main body 11. Toner sensor 21
When the process cartridge 12 is set in the main body 11, the spring 3 is attached to the bottom of the toner tank 21 from the outside.
It is adapted to be pressed by a predetermined pressure by 8.

FIG. 3 shows an outline of the circuit configuration of the laser printer shown in FIG. This laser printer has a CPU (central processing unit) 41 that performs the central functions of various controls. Various circuit devices are connected to the CPU 41 through a bus 42 such as a data bus and an input / output bus. Of these, a ROM (Read Only Memory) 43 is a read-only memory that stores programs representing various control procedures and various fixed data. RAM (random access memory) 44
Is a working memory for storing data that is temporarily necessary for executing the program. The communication control circuit 45 is a circuit that receives print data sent from an information processing device such as a host computer and sends out various status information indicating the status of the printer.

The magnetic permeability sensor 46, which is a toner sensor,
It is connected to the analog / digital conversion circuit 47.
The magnetic permeability sensor 46 outputs an analog electric signal having a magnitude corresponding to the detected magnetic permeability. The analog / digital conversion circuit 47 converts this into a digital signal composed of a plurality of bits. The output of the analog-to-digital conversion circuit 47 is input to the binarization circuit 48, and "on" (1) or "off" (0) based on a predetermined threshold value.
Is converted into a binary signal. The binary signal output from the binarization circuit 48 is sent to the CPU via the bus 42.
41.

The input / output circuit 49 is connected to an operation switch 51 for inputting an operator's instruction and a display section 52 having a warning lamp for warning the remaining amount of toner. Further, the input / output circuit 49 is connected to a device drive unit 53 for driving various mechanical parts of the laser printer such as a main motor, various solenoids and a rotary polygon mirror. Further, an image buffer 54 for storing image data for one page is connected to the CPU 41 via the bus 42. The image data transfer circuit 55 is a circuit that sequentially reads image data from the image buffer 54 and supplies the image data as serial data to the semiconductor laser of the laser optical system.

FIG. 4 shows an example of how the magnetic toner is agitated by the agitator. The same parts as those in FIG. 2 are designated by the same reference numerals, and the description thereof will be appropriately omitted. The agitator 37 rotates at a constant speed in the direction indicated by the arrow 36 while the printer is operating. The magnetic toner 61 is gradually consumed every time it is printed, and the remaining amount stored in the toner tank 21 gradually decreases. The figure shows a state where the toner has been consumed to some extent. When the agitator 37 rotates, the magnetic toner 61 is collected toward the developing roll 33, so that the amount of magnetic toner is temporarily reduced in the portion immediately behind the agitator 35.

Therefore, when the remaining amount is small to some extent, the magnetic permeability detected immediately after the agitator 37 passes in front of the toner sensor 22 temporarily decreases.
The output value of the toner sensor 22 is set to 2 based on a predetermined threshold value.
When the value is converted into a binary signal that takes a value of “0” when the value is equal to or more than the threshold value and a value of “0” when the value is equal to or less than the threshold value, the agitator 37 has a value of 2 when it passes in front of the toner sensor 21.
The time when the value of the value signal becomes "0" changes according to the remaining amount of toner. The time to become "0" becomes shorter as the amount of the magnetic toner increases, and when the toner tank 21 is almost full, the decrease in the magnetic permeability detected is small and the value of the binary signal does not become "0". Conversely, as the remaining amount of magnetic toner decreases,
The magnetic permeability detected after the agitator 37 has passed the front of the toner sensor 21 is reduced to a threshold value or less for a long time. This is because when the remaining amount is small, the time taken for the pits formed after the passage of the agitator 37 to be refilled by the toner around the agitator becomes long.

When the remaining amount of toner further decreases, most of the period in which the magnetic permeability detected by the toner sensor 22 is below the threshold value is reached. Only when the magnetic toner sometimes collapses near the toner sensor 21 due to the rotation of the agitator 37, the magnetic permeability detected temporarily exceeds the threshold value, and the value of the binary signal becomes "1" for a short time. . In this way, it is possible to determine the remaining amount of magnetic toner based on the pattern of the change in the value of the binary signal when the agitator 37 is rotating.
The pattern in which the binary signal changes is in addition to the remaining amount of toner,
It changes variously depending on the shape of the agitator, the rotation speed of the agitator, and the value of the threshold value serving as a reference for binarization. However, if the parameters other than the remaining amount of toner are fixed,
The remaining amount of toner can be discriminated from the pattern of changes in the binary signal.

FIG. 5 shows the state in which the magnetic toner is full and the output waveform of the sensor after binarization at that time. FIG. 5A shows an output waveform of the sensor after binarization. In the figure, the horizontal axis represents time and the vertical axis represents the sensor output value after binarization. Further, FIG. 5 (b) is shown in FIG. 5 (a).
3 schematically shows the remaining amount of magnetic toner when the output waveform shown in FIG. In this way, when the amount of magnetic toner remaining is large, even if the agitator 37 rotates, the magnitude of magnetic permeability does not fall below the threshold value, so the value of the binary signal is always "1" (high level). It is in the state of.
Therefore, it is possible to determine that the remaining amount of toner is almost full by continuously maintaining the state of "1" for a certain time or longer.

FIG. 6 shows a state where the magnetic toner is consumed to some extent and the output waveform of the sensor after binarization at that time. Similar to FIG. 5, FIG. 6A shows the output waveform of the sensor after binarization, and FIG. 6B schematically shows the remaining amount of the magnetic toner at that time. When the remaining amount of toner is about half as shown in FIG.
The sensor output after binarization becomes a state of “0” (low level) at a rate of once every three rotations. Further, since the magnetic toner fills the depression after passing through the agitator 37 in a relatively short time, the time during which the value of the binary signal is "0" is short. Therefore, it is possible to detect that the remaining amount of the toner is about half, based on the fact that the time per one time being “0” is shorter than a certain amount. Further, it is possible to determine the remaining amount of toner based on the fact that the total time during which the state is "0" during a certain time is equal to or shorter than a predetermined reference time.

FIG. 7 shows a state in which the remaining amount of the magnetic toner is further reduced as compared with the state shown in FIG. 6B and the output waveform of the sensor after binarization at that time. Similar to FIG. 5, the output waveform of the sensor after binarization is shown in FIG.
FIG. 7B schematically shows the remaining amount of the magnetic toner at that time. The remaining amount of toner is reduced to about one third as shown in FIG. 7 (b). In such a state, the value of the binary signal becomes "0" once every time the agitator 37 makes one revolution. Further, the time for which "0" continues once is longer than that shown in FIG. 6 (a).

FIG. 8 shows a state in which the remaining amount is further reduced from the state shown in FIG. 7 and the output waveform of the sensor after binarization at that time. Similar to FIG. 5, FIG.
FIG. 8B schematically shows the output waveform of the sensor after binarization, and FIG. 8B schematically shows the remaining amount of the magnetic toner at that time. FIG.
As shown in (b), the remaining amount of toner is extremely small. In such a state, most of the magnetic toner remaining in the toner tank is collected in the vicinity of the developing roll, and therefore, the value of the binary signal is large in most of the rotation period of the agitator. It becomes "0".

The magnetic toner sometimes drops near the toner sensor 21 due to the rotation of the agitator 37,
Since it collapses, the value of the binary signal becomes "1" only at that time. Therefore, while the agitator 37 rotates several times,
The value of the binary signal is “1” for a short time at a rate of times
become. When the remaining amount of magnetic toner is low,
The continuous time of "1" becomes longer. Further, the total time during which the value of the binary signal is "0" within a fixed time becomes short.

FIG. 9 shows a state in which the magnetic toner is empty and the output waveform of the sensor after binarization at that time. Similar to FIG. 5, FIG. 9A schematically shows the output waveform of the sensor after binarization, and FIG. 9B schematically shows the remaining amount of the magnetic toner. When the magnetic toner is empty, the detected magnetic permeability is always below the threshold value.
The value of the value signal is always "0". Therefore, it is possible to determine that the toner in the tank is almost empty based on the fact that the value of the binary signal is continuously "0" for a certain time or longer. In addition, 2 within a certain time
The empty state can also be determined based on the fact that the ratio of the total time when the value of the value signal is "0" is equal to or greater than a predetermined value.

As described above, in accordance with the remaining amount of toner, 2
Since the patterns of changes in the value of the value signal change, if these patterns and the remaining amount of toner at that time are stored in advance in association with each other, the remaining amount of toner is based on the pattern of changes in the value of the binary signal. The amount can be determined. In the following, there are a case where the time of the total sum of the values of the binary signal becomes “0” within a certain time, and a case where the time when the value of the binary signal continuously takes the value of “0” is taken as the reference. A flow of processing for determining the remaining amount of toner will be described for each case based on the number of times of "0" within a fixed time and the history of changes in the number.

FIG. 10 shows the flow of processing for determining the remaining amount of toner based on the total time when the value of the binary signal becomes "0" within a fixed time. Here, the first warning lamp is turned on when the remaining amount becomes small to some extent. Further, the second warning lamp is turned on when the remaining amount of toner is reduced to the extent that about 1000 sheets can be printed. One measurement period for determining the remaining amount of toner is predetermined, and its value is RO.
It is stored in M43. Also, during one measurement period, 2
The sum of the times when the value of the value signal becomes “0” will be referred to as the OFF integrated time. The sum of the time of "0" corresponding to the remaining amount of toner for turning on the first warning lamp is set as the first reference time. Further, the total of the time of "0" corresponding to the remaining amount of toner for turning on the second warning lamp is set as the second reference time. These times are obtained in advance by experiments, and their values are stored in the ROM 43.

Since the agitator 37 does not rotate while the printing is not performed, the process for determining the remaining amount is waiting for the start of the printing (step S101; N).
When printing is started (step S101; Y), a predetermined measurement period is started (step S102).
This is measured by a timer built in the CPU 41. At this time, the off integrated time is initialized to "0". Next, it is determined whether the value of the binary signal which is the sensor output after binarization is "1" or "0" (step S).
103). When the value of the binary signal is “0” (step S
103; Y), the time when the output continuously becomes "0", that is, the time from when the output becomes "0" to when the output changes to "1" is measured (step S104). The measured continuous time of "0" is added to the OFF integrated time (step S10).
5).

Then, it is determined whether or not the measurement period has ended (step S106). If one measurement period has not yet elapsed (step S106; N), the process returns to step S103 to check whether the sensor output is "0". When the value of the binary signal is not "0" (step S103; N), the process proceeds to step S106. In this way, the sum of the times when the value of the binary signal becomes "0" during one measurement period is obtained. When the measurement period ends (step S106; Y), the off-integrated time, which is the sum of the times of "0", and the second reference time are compared in magnitude (step S107).

When the accumulated OFF time is greater than or equal to the second reference time (step S107; Y), a second warning signal is output to notify that the remaining amount of toner is very small. The warning lamp 2 is turned on (step S108). When the off integrated time is shorter than the second reference time (step S107; N), the off integrated time and the first reference time are compared in magnitude (step S).
109). When the accumulated OFF time is greater than or equal to the first reference time (step S109; Y), the first
Warning signal is output to turn on the first warning lamp indicating that the toner has been consumed by about half (step S11).
0).

When the OFF integrated time is shorter than the first reference time (step S109; N), it is determined whether or not the printing operation is completed (step S111). When the print operation is not completed (step S111;
N), since the toner is still being consumed, the process returns to step S102 and the process for determining the remaining amount of toner is continuously performed. When the printing operation is completed (step S1)
11; Y), since the agitator 37 also stops, the process for determining the remaining amount of toner ends (END).

Although the first warning lamp and the second warning lamp are turned on here, the third reference time for which the empty toner is discriminated longer than the second reference time is compared with the OFF integrated time. Needless to say, it may be possible to warn that the toner is empty. In this case, the process of comparing the third reference time and the OFF integrated time is inserted between step S106 and step S107.

In FIG. 11, the value of the binary signal is continuously "0".
Is a flow of a process for determining the remaining amount of toner based on the length of time. The first warning lamp is turned on when the remaining amount is low to some extent, and the second warning lamp is turned on when the remaining amount of toner is reduced to about 1000 sheets. The first is the continuous time of the “0” state corresponding to the remaining amount of toner for turning on the first warning lamp.
And the reference time. Further, the continuous time of the “0” state corresponding to the remaining amount of toner for turning on the second warning lamp is set as the second reference time. These times are obtained in advance by experiments, and their values are stored in the ROM 43.

First, the CPU 41 waits for the start of printing (step S201; N). When printing is started (step S201; Y), it is determined whether the value of the binary signal which is the sensor output after binarization is "1" or "0" (step S202). When the value of the binary signal is "0" (step S202; Y), the time when the output continues to be "0", that is, the time until it changes to "1" is measured (step S203). This is called off duration. Next, the off duration time and the second reference time are compared in magnitude (step S204). When the OFF duration is greater than or equal to the second reference time (step S204; Y), the second warning signal is output and the second warning lamp is turned on (step S20).
5).

When the OFF duration is shorter than the second reference time (step S204; N), the OFF duration and the first
The comparison with the reference time is performed (step S206).
When the off duration is greater than or equal to the first reference time (step S206; Y), the first warning signal is output and the first warning lamp is turned on (step S2).
07). When the OFF duration is shorter than the first reference time (step S206; N) or when the value of the binary signal is "1" (step S202; N), it is determined whether the printing operation is completed (step S202; N). Step S20
8).

When the printing operation is not completed (step S208; N), the toner is still consumed, so the process returns to step S202 to continue the process for determining the remaining amount of toner. When the printing operation is completed (step S208; Y), the process for determining the remaining amount of toner is ended (END). In this example as well, it is possible to compare the third reference time for which the empty toner is longer than the second reference time with the OFF duration and to warn that the toner is empty. Needless to say.

FIG. 12 shows the flow of processing for determining the remaining amount of toner based on the number of times the value of the binary signal becomes "0" and the number of times it becomes "0" in the previous measurement within a fixed time. It represents. Here, the states of the five remaining toner amounts shown in FIGS. 5 to 9 will be identified. The states of the remaining amount of toner shown in FIGS. 5 to 9 will be referred to as first to fifth states, respectively. In addition, the number of times that the value of the binary signal becomes “0” within a certain period of time is determined by the second state, the third state,
The fourth state is measured and stored in advance.
The number of times corresponding to the second state is the second reference number, the number of times corresponding to the third state is the third reference number, and the number of times corresponding to the fourth state is the fourth reference number.

In the third state corresponding to FIG. 7, since the number of times it becomes "0" is large, it is possible to clearly distinguish between the second state and the fourth state. However, in the second state shown in FIG. 6 and the fourth state shown in FIG. 8, the continuous time of "0" is significantly different, but the number of times of "0" within a certain time is significantly different. However, it is difficult to distinguish these states only by the number of times. However, when going from the first state shown in FIG. 5 to the third state shown in FIG. 7, the number of times of “0” gradually increases. On the other hand, when going from the third state to the fifth state shown in FIG. 9, the number of times of "0" gradually decreases. Therefore, the number of "0" s measured during the current measurement period is compared with the number of "0s" during the previous measurement period to determine whether the number is increasing or decreasing, and the toner It is adapted to determine whether the remaining amount is in the second state or the fourth state.

Since the agitator 37 does not rotate while the printing is not performed, the process for determining the remaining amount waits for the printing to be started (FIG. 12, step S3).
01; N). When printing is started (step S30
1; Y), and a predetermined measurement period is started (step S302). This is measured by a timer built in the CPU 41. Next, it is determined whether the value of the binary signal which is the sensor output after binarization is “1” or “0”,
The number of times it becomes "0" is measured (step S303).
Then, it is determined whether or not the measurement period has ended (step S304). When one measurement period has not elapsed (step S304; N), the process returns to step S303, and the measurement of the number of times that the sensor output becomes “0” is continued.
When the measurement period ends (step S304; Y),
The number of times of "0" is compared with the third reference number of times (step S305).

The number of times the value of the binary signal becomes "0" is the third.
When the number of times is larger than the reference number of (step S305; Y),
It is determined that the remaining amount of toner is in the third state shown in FIG. 7 (step S306). If the number of times is greater than the third reference number of times, the state other than the third state cannot occur, so that the third state can be identified without determining whether the number of times increases or decreases. When the number of times of "0" is not greater than the third reference number of times (step S305; N), the number of times of "0" measured this time is compared with the number of times of "0" measured last time (step S307). . When the number of times this time is greater than the number of times of the previous time (step S307; Y),
Since the number of "0" s is increasing,
It is in the process of transitioning to the state of.

Therefore, the number of times of "0" measured this time is set to the second value.
(Step S308). When the number of times of “0” measured this time is greater than the second reference number of times (step S308; Y), it is determined that the remaining toner amount is in the second state shown in FIG. 6 (step S309). If the number of "0" s is not greater than the second reference number (step S3
08; N), and it is determined that the remaining amount of toner is in the first state shown in FIG. 5 (step S310).

When the number of times of "0" measured this time is not larger than the number of times of last time (step S307; N), the number of times of "0" is decreased, so that the third state is changed to the fifth state. It is in the process of transitioning. Therefore, "0" measured this time
Is compared with the fourth reference number of times (step S31).
1). When the number of times of "0" this time is larger than the fourth reference number of times (step S311; Y), it is determined that the remaining amount of toner is in the fourth state shown in FIG. 8 (step S31).
2). When the number of times of “0” measured this time is not larger than the fourth reference number of times (step S311; N), it is determined to be the fifth state shown in FIG. 9 (step S313).

After determining the state of the remaining amount of toner, the value stored as the previous number of "0" is updated to the number of "0" measured this time (step S314). When the printing operation is not completed (step S315;
N)), the process returns to step S302, and the process for determining the state of the remaining toner amount is repeated. When the print operation is completed (step S315; Y), the process is completed (END). In this example, the number of times that the value of the binary signal becomes “0” is the value obtained in one measurement period as it is, but the processing of steps S302 to S304 is repeated a plurality of times to obtain a binary value. This time, the average value of the number of times the signal value has become "0" or the one with a high frequency is the binary signal value "0".
It may be used as the number of times.

In the process for determining the remaining amount of toner described above, the remaining amount can be accurately determined even if the consumed toner is replenished. Even in the process shown in FIG. 12, since the number of times of the previous time and the number of times of this time are compared, if the measured value immediately after replenishing the toner is registered as the value of the previous time, the remaining amount can be accurately determined from the next time. Can be determined. On the other hand, when the toner is not replenished, the history of the toner consumption state can be stored, and the remaining amount of the toner can be determined based on the number of “OFF” times and the consumption state history. For example, if the previous state of the remaining amount is the first state, the next state should be the second state. Therefore, when the number of "offs" this time is less than or equal to the third reference number, the second reference Compare with the number of times. Further, if the previous remaining amount state is the third state, the next state should be the fourth state. Therefore, if the current “off” number is not equal to or greater than the third reference number, the fourth state is set.
It can be compared with the reference number of.

Further, in the embodiment, the toner remaining amount warning is displayed on the operation panel of the printer by the display lamp, but the host computer may be notified of the toner remaining amount state via a network or the like. .
By displaying the status of the remaining amount of toner on the screen of the host computer side, the status of the printer can be easily known remotely. Further, in the embodiment, the toner sensor is arranged at the bottom of the toner tank from the outside,
The sensor may be provided at another position depending on the minimum amount of toner to be detected. For example, the minimum amount to be detected is 100
When the amount of printing for 0 sheets can be printed, the toner sensor may be arranged in the vicinity of the toner surface in a state where that much toner is accumulated in the toner tank.

Further, the toner sensor may be provided inside the toner tank of the process cartridge.
Further, in the embodiment, the sensor output is converted into a digital signal, and the remaining amount of toner is discriminated based on the pattern of change in the value of the binary signal obtained by binarizing the digital signal. The state or the state of an analog signal may be used. In this case, it is necessary to store in advance a change pattern corresponding to the signal format.

[0056]

As described above, according to the first aspect of the present invention, the remaining amount of toner is determined based on the pattern in which the magnitude of the magnetic field at a predetermined position changes according to the stirring by the toner stirring means. , The remaining amount can be identified in multiple stages.

According to the second aspect of the present invention, the magnitude of the detected magnetic field at the predetermined position is binarized, and the sum of the times when the value takes one of the values during a fixed time is calculated. Based on this, the remaining amount of toner is determined. Thereby, the remaining amount of toner can be easily discriminated in a plurality of stages.
In addition, the detection accuracy is high because the sum is obtained within a fixed time.

Further, according to the invention described in claim 3, the magnitude of the magnetic field at the detected predetermined position is binarized, and the toner is based on the time when the value continuously takes one of the values. Since the remaining amount of toner is determined, the remaining amount of toner can be easily detected in a plurality of stages.

According to the fourth aspect of the invention, the remaining amount of toner is discriminated based on the number of times the magnitude of the magnetic field after binarization takes one of the values within a fixed time and the history thereof. Therefore, the remaining amount of toner can be easily and accurately detected in a plurality of stages.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a configuration of a laser printer using a toner remaining amount detecting device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a configuration around a process cartridge and a toner sensor.

FIG. 3 is a block diagram showing an outline of a circuit configuration of the laser printer shown in FIG.

FIG. 4 is an explanatory diagram showing an example of how magnetic toner is agitated by an agitator.

FIG. 5 is an explanatory diagram showing a state where the magnetic toner is full and an output waveform of the sensor after binarization at that time.

FIG. 6 is an explanatory diagram showing a state where magnetic toner is consumed to some extent and an output waveform of the sensor after binarization at that time.

FIG. 7 is an explanatory diagram showing a state in which the remaining amount is further reduced from the state shown in FIG. 6 and the output waveform of the sensor after binarization at that time.

FIG. 8 is an explanatory diagram showing a state in which the remaining amount is further reduced compared to the state shown in FIG. 7 and the output waveform of the sensor after binarization at that time.

FIG. 9 shows a state in which the magnetic toner is empty and 2 at that time.
It is explanatory drawing showing the output waveform of the sensor after value conversion.

FIG. 10 is a flowchart showing a flow of processing for determining the remaining amount of toner based on the total time when the value of the binary signal becomes “0” within a fixed time.

FIG. 11 is a flowchart showing the flow of processing for determining the remaining amount of toner based on the length of time during which the value of the binary signal continuously becomes “0”.

FIG. 12 shows a flow of processing for determining the remaining amount of toner based on the number of times the value of a binary signal becomes “0” and the number of times of “0” in the previous measurement within a fixed time. It is a flow chart.

[Explanation of symbols]

21, 46 ... Permeability sensor, 32 ... Toner tank, 37
… Agitator, 41… CPU, 42… Bus, 43… RO
M, 44 ... RAM, 47 ... Analog / digital conversion circuit, 48 ... Binarization circuit, 52 ... Display unit

Claims (4)

[Claims] 1. A toner storage unit for storing magnetic toner, a toner stirring unit for stirring the magnetic toner stored in the toner storage unit, and a predetermined position of a magnetic field generated by the magnetic toner stored in the toner storage unit. Magnetic field detection means for detecting the magnitude of the magnetic field and a magnetic toner stored in the toner storage means with a pattern of change in the magnitude of the magnetic field detected by the magnetic field detection means when the toner stirring means is stirring. Of the magnetic field change pattern storage means stored in association with the remaining amount of the magnetic field, and a pattern of a change in the magnitude of the magnetic field detected by the magnetic field detection means when the toner stirring means is stirring the magnetic toner. Collating means for collating with the pattern stored in the pattern storing means and the remaining amount of the magnetic toner in the toner containing means based on the collating result of the collating means. Toner remaining amount detection apparatus characterized by comprising a toner remaining amount discrimination means that. 2. A toner containing means for containing a magnetic toner, a toner agitating means for agitating the magnetic toner contained in the toner containing means, and a predetermined position of a magnetic field produced by the magnetic toner contained in the toner containing means. Magnetic field detecting means for detecting the magnitude of the magnetic field, binarizing means for binarizing the magnitude of the magnetic field detected by the magnetic field detecting means on the basis of a predetermined threshold value, and the toner stirring means for magnetic toner. The total time when the output value of the binarizing means becomes a predetermined one value within a certain time while stirring is associated with the remaining amount of the magnetic toner accommodated in the toner accommodating means. And the magnetic field change pattern storage means stored by the toner storage means and the sum of the times when the output value of the binarizing means is the one of the fixed times while the toner stirring means is stirring the magnetic toner. A sum total time measuring means, a comparing means for comparing the time obtained by the sum total time measuring means with the time stored in the magnetic field change pattern storing means, and the toner storing means in the toner containing means based on the comparison result of the comparing means. And a toner remaining amount determining means for determining the remaining amount of the magnetic toner. 3. A toner containing means for containing a magnetic toner, a toner agitating means for agitating the magnetic toner contained in the toner containing means, and a predetermined position of a magnetic field produced by the magnetic toner contained in the toner containing means. Magnetic field detecting means for detecting the magnitude of the magnetic field, binarizing means for binarizing the magnitude of the magnetic field detected by the magnetic field detecting means on the basis of a predetermined threshold value, and the toner stirring means for magnetic toner. The length of time during which the output value of the binarizing means during stirring is continuously one of the predetermined values is associated with the remaining amount of the magnetic toner stored in the toner storing means. The stored magnetic field change pattern storage means and continuous time for measuring the length of time during which the output value of the binarization means continuously reaches the one value while the toner stirring means is stirring the magnetic toner. Measuring means Comparing means for comparing the length of time obtained by the continuous time measuring means with the length of time stored in the magnetic field change pattern storage means; A remaining toner amount detection device, comprising: a remaining toner amount determination unit that determines the remaining amount of magnetic toner. 4. A toner containing means for containing magnetic toner, a toner agitating means for agitating the magnetic toner contained in the toner containing means, and a predetermined position of a magnetic field produced by the magnetic toner agitated by the toner agitating means. Magnetic field detecting means for detecting the magnitude of the magnetic field, binarizing means for binarizing the magnitude of the magnetic field detected by the magnetic field detecting means on the basis of a predetermined threshold value, and the toner stirring means for magnetic toner. The number of times that the output value of the binarizing means becomes a predetermined one value within a certain period of time while stirring is stored in association with the remaining amount of magnetic toner stored in the toner storing means. And a magnetic field change pattern storing means for counting the number of times that the output value of the binarizing means has reached one of the values within the fixed time while the toner stirring means is stirring the magnetic toner. Means, history storage means for storing a history of the number of times counted by the counting means, comparison means for comparing the number of times counted by the counting means with the number of times stored in the magnetic field change pattern storage means, Toner remaining amount determining means for determining the remaining amount of magnetic toner in the toner containing means based on the comparison result of the means and the history of the number of times stored in the history storing means. Remaining amount detection device.