Patent Application
20190235413
The present disclosure relates to an image forming apparatus to which a container containing developer is attachable and from which the container is detachable.
An electrophotographic image forming apparatuses forms an image by using toner stored in a container, When an amount of the toner stored in the container is less than a predetermined amount, an output image with less density is formed. Thus, in this case, a user replaces this container mounted on a mounting portion of the image forming apparatus with another container containing toner.
Used containers that have been refilled with toner have commercially been available, and Japanese Patent Application Laid-Open No. 2007-102024 discuses an image forming apparatus that determines whether a container mounted on a mounting portion is a refilled container. In the case of the image forming apparatus discussed in Japanese Patent Application Laid-Open No. 2007-102024, information indicating that the volume of the toner in the container is zero is recorded in a memory arranged on the container. In addition, when a sensor detects that there is toner in the container, the image forming apparatus determines that this mounted container is a refilled container.
In addition, U.S. Pat. No. 6,415,112 discusses an image forming apparatus that detects an amount of toner stored in a container mounted on a mounting portion based on an output voltage that changes with the amount of the toner present between a plurality of electrodes arranged on the container. The image forming apparatus discussed in U.S. Pat. No. 6,415,112 compares the value of the output voltage with a threshold and detects the amount of the toner based on the comparison result.
However, since density of the toner in a container changes depending on environmental conditions (e.g., the temperature and the humidity), the amount of the toner present between the electrodes may change depending on the environmental conditions. Thus, the threshold to be compared with the output voltage value cannot be determined uniquely.
In addition, physical properties of toner with which a used container is refilled may differ from those of the toner manufactured by the maker that manufactures the image forming apparatus. Thus, even when the output voltage value is compared with the threshold, the image forming apparatus may not determine whether the container mounted on the mounting portion is a refilled container.
Thus, even if information indicating that the volume of the toner is zero is recorded in a memory, the image forming apparatus cannot determine whether a refilled container has been mounted on the mounting portion or another container without toner has been mounted on the mounting portion.
According to an aspect of the present disclosure, an image forming apparatus to form an image by using toner, the image forming apparatus includes a mounting portion on which a container containing the toner is mounted, a motor configured to rotate an agitation member in the container mounted on the mounting portion, an electrical circuit configured to acquire an output value corresponding to electrostatic capacitance between a plurality of electrodes of the container mounted on the mounting portion, and a controller configured to: control the motor to rotate the agitation member of the container mounted on the mounting portion, control the electrical circuit to acquire the output value, detect the amount of the toner in the container mounted on the mounting portion based on the output value acquired by the electrical circuit, and write predetermined information in a memory of the container mounted on the mounting portion in a case where the detected amount is below a predetermined amount, wherein, in a case where the predetermined information is stored in the memory of the container currently mounted on the mounting portion, the controller determines whether the container currently mounted on the mounting portion is a refilled container based on the output value acquired by the electrical circuit while the agitation member is rotating.
Further features of the present disclosure will become apparent from the following description of embodiments with reference to the attached drawings.
An overall configuration of an electrophotographic image forming apparatus (image forming apparatus) will be described with reference to
In the first embodiment, the first to fourth image forming units have substantially the same configuration and perform substantially the same operation except for colors of the images formed. Thus, unless the image forming units SY to SK need to he distinguished from each other, the image forming units SY to SK will he collectively described by omitting the Y to K included in their respective reference characters. In the first embodiment, the image forming apparatus 100 includes four photosensitive drums 1 (1Y to 1K). Each of the photosensitive drums 1 rotates in a direction of an arrow A in
Each of the photosensitive drums 1 is a photosensitive member formed of an aluminum cylinder, and a photosensitive layer is formed on a surface of the aluminum cylinder. Each of the charging rollers 2 uniformly charges the surface of the corresponding photosensitive drum 1. The scanner unit 3 emits laser based on image data to form an electrostatic latent image on each of the photosensitive drums 1. In addition, developing units 4 (4Y to 4K) and cleaning blades 6 (6Y to 6K) are arranged in the vicinity of the respective photosensitive drums 1. Each of the developing units 4 includes at least a developing roller 17 that bears developer.
The image forming apparatus 100 also includes a belt-like transfer member 5 that faces the four photosensitive drums 1 and that transfers toner images on the photosensitive drums 1 onto a recording medium (primary transfer process). In addition, in the first embodiment, toner T (TY to TK), which is nonmagnetic mono-component developer, is used in the developing units 4.
The image forming apparatus 100 also includes photosensitive units 13, and each of the photosensitive units 13 includes a removed-toner storage unit 14a (14aY to 14aK) (see
Each of the process cartridges 7 can be mounted on the image forming apparatus 100 in a direction of an arrow G in
On an inner circumferential surface of the transfer member 5, four primary transfer rollers 8 (8Y to 8K) are arranged side by side to face the respective photosensitive drums 1. On an outer circumferential surface of the transfer member 5, a secondary transfer roller 9 is arranged at a position to face the secondary transfer counter roller 27.
When the image forming apparatus 100 forms an image, first, the charging rollers 2 uniformly charge the surfaces of the respective photosensitive drums 1. Next, the scanner unit 3 emits laser light to scan and expose the surfaces of the photosensitive drums 1 therewith. Consequently, an electrostatic latent image based on image data is formed on each of the photosensitive drums I. The electrostatic latent images formed on the photosensitive drums 1 are developed by the respective developing units 4 as toner images. The toner images formed on the photosensitive drums 1 are primarily transferred onto the transfer member 5 by the respective primary transfer rollers 8.
For example, when the image forming apparatus 100 forms a full-color image, the image forming units SY to SK, which are the first to fourth image forming units, sequentially perform the above process to sequentially superimpose the toner images of respective colors onto the transfer member 5. Then, the recording medium is conveyed to a secondary transfer unit in synchronization with movement of the transfer member 5. Then, the toner images of four colors on the transfer member 5 are secondarily transferred onto the recording medium at once by the secondary transfer roller 9, which is in contact with the transfer member 5 via the recording medium.
Then, the recording medium, on which the toner images have been transferred, is conveyed to a fixing unit 10 in which the recording medium is heated and pressurized, Consequently, the toner images are fixed on the recording medium. The toner that remains on the photosensitive drums 1 after the primary transfer process is removed by the respective cleaning blades 6. In addition, the toner that remains on the transfer member 5 after the secondary transfer process is removed by a belt cleaning unit 11. The removed toner (waste toner) is discharged to a waste toner box (not illustrated) of the image forming apparatus 100.
An overall configuration of the process cartridges 7 mounted on the image forming apparatus 100 will be described with reference to
The recessed portion 18d has a groove shape that extends in the lengthwise direction of the developing roller 17. The first and second electrodes 31 and 32 also extend in the lengthwise direction of the developing roller 17. A sheet member, which will be described below, also extends in the lengthwise direction. The length of the recessed portion in the lengthwise direction of the developing roller 17 is longer than the lengths of the first electrode 31, the second electrode 32, and the sheet member. A leading end of the sheet member can enter the recessed portion.
The developing unit 4 includes a toner storage chamber 18a, which is a space in the corresponding container main body 19, and a developing chamber 18b in which the developing roller 17 is arranged. In addition, an opening 18c through which the toner storage chamber 18a and the developing chamber 18b are communicated is formed in the developing unit 4. The toner storage chamber 18a is located below the developing chamber 18b. The developing chamber 18b includes a toner supplying roller 20, which serves as a developer supply member that is in contact with the developing roller 17 and that rotates in a direction of an arrow E, and a developer regulating member 21, which regulates thickness of a toner layer formed on the developing roller 17.
The toner storage chamber 18a of the developer container 190 includes the agitation member 23, which agitates the stored toner T and conveys the toner to the toner supplying roller 20 via the opening 18c. The agitation member 23 includes a rotation shaft 23a parallel to the rotational axis direction of the developing roller 17, and a flexible agitation sheet 23b. Since a leading end of the agitation sheet 23b is attached to the rotation shaft 23a, the agitation sheet 23b rotates as the rotation shaft 23a rotates. In this way, the toner is agitated. While rotating, the agitation member 23 slides on an area including at least a bottom portion 18f of an inner surface 19A of the container main body 19.
When the agitation member 23 agitates the toner, since the agitation sheet 23b comes in contact with the inner surface 19A of the container main body 19, the agitation sheet 23b is bent while rotating. However, the agitation sheet 23b is released from this bent state at a release position 18e on the inner surface 19A of the container main body 19. The agitation sheet 23b is released from the bent state when traveling past the release position 18e, and then, the toner on the sheet member jumps up by a restoring force due to the release from the bent state. This toner is conveyed to the toner supplying roller 20 in the developing chamber 18b and to the developing roller 17 via the opening 18c.
A distance W0 from the rotation shaft 23a to the leading end of the agitation sheet 23b is set to be longer than a distance W1 from the rotation shaft 23a to the bottom portion 18f of the container main body 19 so that the toner on the bottom portion 18f of the container main body 19 can be agitated and conveyed. Then, states of the agitation sheet 23b and the toner during one rotation of the agitation member 23 will be descried with reference to
When the agitation sheet 23b further rotates in the direction of the arrow F, as illustrated in
As illustrated in
The cleaning blade 6 is formed of an elastic member 6a for removing the toner that remains on the surface of the photosensitive drum I after the primary transfer (waste toner), and a supporting member 6b for supporting the elastic member 6a, The toner removed from surface of the photosensitive drum 1 by the cleaning blade 6 is stored in the corresponding removed-toner storage unit 14a formed by the cleaning blade 6 and the frame member 14.
A configuration for detecting the amount of the toner in the toner storage chamber 18a (toner remaining amount) will be described with reference to
Any electrode may be used as the above electrodes 31 and 32 as long as the electrode can detect the electrostatic capacitance. For example, a metal plate such as SUS or a conductive resin may be used, In the present embodiment, conductive resin sheets obtained by dispersing carbon black, which is a conductive material, in resin are used.
As illustrated in
The recessed portion 18d is formed at a position where the toner does not enter while the toner is not agitated by the agitation member 23. More specifically, in the toner storage chamber 18a, the recessed portion 18d is located upstream of the opening 18c and the release position 18e, and is located downstream of the bottom portion 18f of the toner storage chamber 18a in the rotation direction of the of the agitation member 23. The recessed portion 18d is formed to be located vertically below the release position 18e and vertically above the bottom portion 18f in a state where the process cartridge 7 is mounted on the corresponding mounting portion 200.
In the present embodiment, while the toner is not agitated in the container main body 19, since the toner that has previously entered the recessed portion 18d is already discharged by its own weight from the recessed portion 18d, the toner no longer remains in the recessed portion 18d. The recessed portion 18d is formed at a position where the agitation sheet 23b passes after the agitation sheet 23b travels past the bottom portion 18f and before an angle β of the agitation sheet 23b reaches an angle at which the toner on the agitation sheet 23b falls off the agitation sheet 23b.
As illustrated in
Since the distance from the wall surface 18d1 to the rotation shaft 23a and the distance from the wall surface 18d2 to the rotation shaft 23a are longer than the distance W2, in a case where the toner is conveyed by the conveyance regulating surface 18g and the agitation sheet 23b, the toner can be conveyed without hindering a trajectory of the agitation sheet 23b. In addition, as described above, the distance from the part of the wall surface 18d1 closest to the rotation shaft 23a to the rotation shaft 23a and the distance from the part of the wall surface 18d2 closest to the rotation shaft 23a to the rotation shaft 23a are shorter than the distance W0. In this way, the toner on the agitation sheet 23b is pushed into the recessed portion 18d by the agitation member 23, and the recessed portion 18d can be filled with the toner stably.
How the toner on the agitation member 23 enters and falls off of the recessed portion 18d will be described with reference to
When the agitation sheet 23b further rotates, the agitation sheet 23b travels past the recessed portion 18d, as illustrated in
As described above, the toner remains in the recessed portion 18d between when the agitation sheet 23b starts to push the toner surface and when the agitation sheet 23b travels past the release position 18e. After the agitation sheet 23b travels past the release position 18e, the toner on the agitation sheet 23b jumps up. Thus, the state of the toner in the container main body 19 is not stable, and it is not suitable to detect whether the toner is present in the recessed portion 18d. If, for example, the recessed portion 18d is located at the bottom portion 18f, the recessed portion 18d is open upwards. In this case, the toner in the recessed portion 18d cannot fall by its own weight, and the toner may always remain in the recessed portion 18d.
Thus, to discharge the toner in the recessed portion 18d from the recessed portion 18d after the agitation sheet 23b travels past the recessed portion 18d, the recessed portion 18d needs to be formed above the bottom portion 18f. In addition, the inner walls of the recessed portion 18d need to be formed at such an angle that the toner in the recessed portion 18d is discharged by its own weight. Then, it is desirable that the recessed portion 18d be formed upstream of the release position 18e and downstream of the bottom portion 18f in the rotation direction of the agitation member 23 (direction of the arrow F) and be formed at a position as high as possible on the inner surface 19A of the container main body 19.
The first and second electrodes 31 and 32 are arranged in the recessed portion 18d in a direction substantially parallel to the rotational axis direction of the developing roller 17. A gap is formed between the first and second electrodes 31 and 32. As illustrated in
As illustrated in
The memory 30 is a non-volatile storage medium (storage unit) such as an electrically erasable programmable read-only memory (EEPROM). In a state where the process cartridge 7 is mounted on the corresponding mounting portion 200 of the image forming apparatus 100, a writing unit 39 of the image forming apparatus 100 can record (write) information about the number of prints and an out-of-toner state in the memory 30. Likewise, in a state where the process cartridge 7 is mounted on the corresponding mounting portion 200 of the image forming apparatus 100, a reading unit 40 of the image forming apparatus 100 can read the above information stored in the memory 30. The out-of-toner state is a state in which the amount of the toner stored in the container main body 19 is less than a predetermined amount.
Since a permittivity of toner is higher than that of the air, when the toner enters the area between the first and second electrodes 31 and 32, the electrostatic capacitance between the first and second electrodes 31 and 32 increases. Thus, when the toner conveyed by the agitation member 23 travels the area between the first and second electrodes 31 and 32, the electrostatic capacitance between the first and second electrodes 31 and 32 increases. Then, when the agitation member 23 travels past the recessed portion 18d and the toner present between the first and second electrodes 31 and 32 falls by its own weight, the electrostatic capacitance between the first and second electrodes 31 and 32 decreases. In addition, when the electrostatic capacitance between the first and second electrodes 31 and 32 increases, an output voltage decreases. When the electrostatic capacitance between the first and second electrodes 31 and 32 decreases, the output voltage increases.
The time needed for the toner to travel past the area between the first and second electrodes 31 and 32 changes depending on the toner remaining amount in the container main body 19.
On the other hand,
Time duration between when the output voltage starts to decrease in
A method for measuring the time duration t in which the toner travels past the recessed portion 18d from a waveform of an output voltage based on the electrostatic capacitance will be described below with reference to
In
The output voltage varies depending on variation of the electrostatic capacitance between the first and second electrodes 31 and 32. Thus, in a case where the reference value Vc is a fixed value, the time duration t cannot possibly be measured. For example, in a case where the permittivity of the toner in the container main body 19 is low, since the amount of the change of the electrostatic capacitance between the first and second electrodes 31 and 32 is small, the change of the output voltage is also small. In this case, there are cases in which the reference value Vc is above a maximum value Vmax of the output voltage (Vc>Vmax) or is below a minimum value Vmin (Vc<Vmin). In these cases, the time duration t cannot be measured stably.
In addition, when the permittivity of the toner changes with change of environmental conditions such as the temperature and the humidity under which the image forming apparatus 100 is used, the output voltage varies significantly. In this case, the output voltage value can be deviated from the reference value Vc, and consequently, the time duration t cannot possibly be measured. Thus, it is desirable that the reference value Vc be varied depending on the waveform of the output voltage. Hereinafter, a method for setting the reference value Vc will be described.
The image forming apparatus 100 further includes the voltage generation circuit 35, the voltage detection circuit 36, the writing unit 39, the reading unit 40, an electrostatic capacitance detection circuit 401, and a motor 410. Since the voltage generation circuit 35, the voltage detection circuit 36, the writing unit 39, and the reading unit 40 have already been described, a redundant description thereof will be avoided. The motor 410 is a drive source for rotating the rotation shaft 23a via a gear train of the apparatus main body 100A. The electrostatic capacitance detection circuit 401 is an electrical circuit including the voltage generation circuit 35 and the voltage detection circuit 36. The electrostatic capacitance detection circuit 401 is electrically connected to the first and second electrodes 31 and 32 via the first and second contacts 33 and 34. The electrostatic capacitance detection circuit 401 causes the voltage generation circuit 35 to generate a voltage at a predetermined timing and outputs a voltage detected by the voltage detection circuit 36 to the CPU 420.
When setting the reference value Vc, first, the CPU 420 measures the maximum value Vmax or the minimum value Vmin from the waveform of the output voltage detected by the voltage detection circuit, and sets the reference value Ye based on the maximum value Vmax or the minimum value Vmin. For example, the CPU 420 sets a value by subtracting a fixed value a from the maximum value Vmax of the output voltage as the reference value Vc (Vc=Vmax−α). In this example, the fixed value α is a value determined by experiments based on, for example, variations in an arrangement relationship between the first and second electrodes 31 and 32 and variations in the properties (permittivity) of the toner used. Alternatively, the CPU 420 may set a value by adding the fixed value α to the minimum value Vmin of the output voltage as the reference value Vc (Vc=Vmin+α).
The CPU 420 detects the toner remaining amount in the container main body 19 by determining the reference value Vc and measuring the time duration t by using the reference value Vc as a reference. Each time the CPU 420 detects the toner remaining amount in the container main body 19, the CPU 420 determines the reference value Vc. In the above example, the CPU 420 determines the toner remaining amount based on the time duration in which the output voltage is below the threshold. However, alternatively, the CPU 420 may determine the toner remaining amount based on the time duration in which the output voltage is above the threshold.
As described above, since the reference value Vc is newly set each time the CPU 420 detects the toner remaining amount in the container main body 19, the time duration t can be measured accurately, and the toner remaining amount can be detected stably. The toner remaining amount acquisition method as described above is performed at predetermined timings from when the developing unit 4 has not been used yet and the container main body 19 is sufficiently filled with the toner to when the container main body 19 is out of the toner.
In a case where the container main body 19 includes a large toner remaining amount and the toner is always present in the recessed portion 18d, the electrostatic capacitance between the first and second electrodes 31 and 32 does not change, and the output voltage indicates substantially the same value. Thus, even if the reference value Vc is set, the value of the time duration t indicates approximately zero. On the other hand, when the container main body 19 includes a very small or de minimis toner remaining amount, even if the agitation member 23 rotates, little toner enters the recessed portion 18d. In this case, the electrostatic capacitance between the first and second electrodes 31 and 32 does not change either, and the value of the time duration t indicates approximately zero. In these cases, the CPU 420 may not be able to distinguish between the state where the recessed portion 18d is filled with the toner and the state where the container main body 19 is out of the toner.
Thus, after the time duration t exceeds a predetermined duration, the CPU 420 determines whether the toner remaining amount in the container main body 19 is below a predetermined amount based on the number of recording media on which the image forming apparatus 100 has formed images (number of sheets on which images have been formed). For example, if the time duration t exceeds the predetermined duration and the number of sheets on which images have been formed in the state where the process cartridge 7 is mounted on the corresponding mounting portion 200 has reached, for example, 3,000, the CPU 420 determines that the toner remaining amount in the container main body 19 is less than the predetermined amount. Information about the number of sheets on which images have been formed in the state where the process cartridge 7 is mounted on the mounting portion 200 is written at a predetermined timing in the memory 30 of the process cartridge 7. The CPU 420 causes the reading unit 40 to read the information about the number of sheets on which images have been formed from the memory 30, and if the number of sheets has reached, for example, 3,000, the CPU 420 determines that the toner remaining amount in the container main body 19 is less than the predetermined amount. If the CPU 420 determines that the toner remaining amount in the container main body 19 is less than the predetermined amount, the CPU 420 causes the writing unit 39 to write information indicating the out-of-toner state in the memory 30 of the process cartridge 7. Then, the CPU 420 displays a screen requesting replacement of the process cartridge 7 on a touch panel (not illustrated).
There is a case in which the image forming apparatus 100 that detects the toner remaining amount based on the time duration t cannot accurately determine whether the process cartridge 7 mounted on the corresponding mounting portion 200 has been refilled with toner by using the time duration t. This is because the time duration t in which the recessed portion 18d is filled with the toner and the time duration t in which the container main body 19 is out of the toner are approximately zero. This will be described in detail with reference to the drawings.
As the toner in the cartridge is consumed and the toner remaining amount therein is consequently reduced, the output voltage increases. However, the output voltage (2.75 V) in the state where the cartridge CRG-A is sufficiently filled with the toner is higher than the maximum output voltage (2.44 V) in the state where the cartridge CRG-B indicates the out-of-toner state. Thus, in a case where the output voltage decreases in a state where information indicating the out-of-toner state is stored in the memory 30 of the process cartridge 7 and if the same cartridge is used, the CPU 420 can determine that the process cartridge 7 has been refilled with toner. However, the following issues may arise.
The first issue is that, after the cartridge CRG-B indicates the out-of-toner state, if the cartridge CRG-B is replaced by a refilled cartridge CRG-A, the CPU 420 cannot determine whether the refilled cartridge CRG-A has newly been mounted. This is because the output voltage (2.75 V) of the cartridge CRG-A is higher than the output voltage (2.44 V) of the cartridge CRG-B in the out-of-toner state. Since the output voltage has increased, the CPU 420 cannot determine whether the cartridge CRG-B is mounted or another cartridge (cartridge CRG-A) is mounted based on the output voltage.
The second issue is that, after the cartridge CRG-A indicates the out-of-toner state, if the cartridge CRG-B indicating the out-of-toner state is mounted, the CPU 420 erroneously detects that a refilled cartridge has been mounted although the cartridge CRG-B has not been refilled with toner. This is because the output voltage has decreased from the output voltage (3.06 V) of the cartridge CRG-A indicating the out-of-toner state to the output voltage (2.44 V) of the cartridge CRG-B indicating the out-of-toner state. Since the output voltage has decreased, the CPU 420 erroneously detects that the cartridge CRG-B is a refilled cartridge.
Thus, the CPU 420 determines whether the process cartridge 7 mounted on the mounting portion 200 is a refilled process cartridge based on the information indicating the out-of-toner state and a fluctuation amount of the output voltage read from the memory 30. Hereinafter, the fluctuation amount of the output voltage will be described.
As illustrated in
The toner is consumed as images are formed, whereby the amount of the toner is reduced. Thus, as illustrated in
If the amount of the toner falls below 30 g as the toner is consumed, the developing roller is not sufficiently supplied with the toner. A state in which the amount of the toner is reduced to a level at which the developing roller 17 cannot be supplied with the sufficient toner and the amount of the toner reaches a predetermined amount or less is called an “out-of-toner state”. In the out-of-toner state, the time duration in which no toner is present between the electrodes is further extended. As illustrated in
More specifically, the fluctuation amount ΔV of the refilled process cartridge 7 is smaller than the fluctuation amount ΔV of the process cartridge 7 indicating the out-of-toner state. Thus, in a case where information indicating the out-of-toner state is stored in the memory 30 and the fluctuation amount ΔV is smaller than a threshold ΔVth, the CPU 420 determines that the process cartridge 7 mounted on the mounting portion 200 is the refilled process cartridge. Hereinafter, refill detection processing will be described with reference to the control block diagram in
In a case where power supply of the image forming apparatus 100 is turned on or the process cartridge 7 is replaced, the CPU 420 performs the refill detection processing. In Step 1, when starting the refill detection processing, the CPU 420 causes the reading unit 40 to read the memory 30 of the process cartridge 7 mounted on the corresponding mounting portion 200, and determines whether information indicating the out-of-toner state is stored in the memory 30. If the information indicating the out-of-toner state is not stored in the memory 30 (NO in Step 1), the CPU 420 determines that the process cartridge 7 mounted on the mounting portion 200 is not a refilled process cartridge, and ends the refill detection processing.
If the CPU 420 determines that the information indicating the out-of-toner state is stored in the memory 30 (YES in Step 1), in Step 2, the CPU 420 controls the motor 410 to drive the agitation member 23. Then, in Step 3, the CPU 420 waits for a predetermined time until the rotation speed of the agitation member 23 stabilizes. Subsequently, in Step 4, the CPU 420 controls the electrostatic capacitance detection circuit 401 to measure the output voltage, and determines whether the fluctuation amount (ΔV) of the output voltage is below the threshold ΔVth. In Step 4, the CPU 420 determines whether the fluctuation amount ΔV of the output voltage outputted from the electrostatic capacitance detection circuit 401 while the agitation member 23 is rotating is below the threshold ΔVth. For example, the threshold ΔVth is 0.15 V. However, the value of the threshold ΔVth is not limited thereto. The threshold ΔVth is determined in advance by experiments and stored in the ROM 421. If the fluctuation amount ΔV is the threshold ΔVth or more (NO in Step 4), the CPU 420 determines that the process cartridge 7 mounted on the mounting portion 200 is not a refilled process cartridge, and ends the refill detection processing.
On the other hand, in Step 4, if the fluctuation amount ΔV is less than the threshold ΔVth (YES in Step 4), in Step 5, the CPU 420 initializes the information about the number of sheets on which images have been formed that is stored by the writing unit 39 in the memory 30 of the process cartridge 7. The initial value of the number of sheets is 0. Then, the CPU 420 ends the refill detection processing.
As described in the present embodiment, when information indicating the out-of-toner state is stored in the memory 30 of the process cartridge 7, the CPU 420 measures an amplitude of the output voltage (i.e., fluctuation amount ΔV), and determines whether the cartridge has been refilled by comparing the amplitude (ΔV) with the threshold Vth. In this way, even with a configuration in which accuracy in the detection of the toner remaining amount is insufficient, whether the cartridge has been refilled with the toner can be detected accurately.
More specifically, the image forming apparatus 100 according to the present embodiment can accurately determine whether an individual process cartridge 7 mounted on the corresponding mounting portion 200 is a refilled process cartridge.
In the image forming apparatus 100 according to the first embodiment, the process cartridge 7 including the photosensitive unit 13 and the developing unit 4 can be attached to the corresponding mounting portion 200 and detached therefrom. However, alternatively, the photosensitive unit 13 and the developing unit 4 may be configured to be individually attachable to the corresponding mounting portion 200 and detachable therefrom. In the case of the image forming apparatus 100 with this configuration, the corresponding developing unit 4 is replaced when the out-of-toner state occurs. More specifically, the developing unit 4 serves as a container containing the toner. This configuration is more economical than the configuration using the process cartridge 7 including the photosensitive unit 13 and the developing unit 4. In addition, since an amount of waste can be reduced, this configuration is more environmentally friendly.
More specifically, the image forming apparatus 100 according to the present embodiment can accurately determine whether the developing unit 4 mounted on the corresponding mounting portion 200 is a refilled developing unit.
A second embodiment will be described with reference to
The image forming apparatus 100 transfers a rotation driving force to the process cartridges 60 and the toner cartridges 90. In addition, the image forming apparatus 100 applies biases (a charging bias, a developing bias, etc.) to the process cartridges 60. In addition, the process cartridges 60 and the toner cartridges 90 are independently attachable to the image forming apparatus 100 and detachable therefrom.
As illustrated in
The toner cartridge 90 includes a supply toner container 90a that contains the toner. The supply toner container 90a includes a supply opening 90c for supplying the toner to the process cartridge 60. In addition, the toner container 81a of the process cartridge 60 includes a receiving opening 81c, and the inside of the supply toner container 90a and the inside of the toner container 81a communicate with each other via the supply opening 90c and the receiving opening 81c. By the process cartridge 60 and the toner cartridge 90 being mounted on the image forming apparatus 100, the supply opening 90c and the receiving opening 81c communicate with each other, and the toner is supplied from the cartridge 90 to the developing unit 80.
A configuration for detecting the toner remaining amount in the supply toner container 90a of the toner cartridge 90 will be described. As illustrated in
As described above, the image forming apparatus according to the second embodiment can accurately determine whether the individual toner cartridge 90 has been refilled. In addition, in the case of the image forming apparatus according to the second embodiment, the individual supply toner container 90a is attachable to the corresponding developing unit 80 and detachable therefrom. Thus, by replacing the supply toner container 90a, toner can be supplied to the corresponding developing unit 80.
A third embodiment will be described. Components of an image forming apparatus 100 according to the third embodiment that have the same functions as those of the image forming apparatus 100 according to the first embodiment will be denoted by the same reference characters, and redundant descriptions thereof will be avoided. In the image forming apparatus 100 according to the third embodiment, first electrodes 51 and second electrodes 52 are arranged on the image forming apparatus 100. The configurations of the image forming apparatus 100 and the process cartridges 7 according to the third embodiment are similar to those of the image forming apparatus 100 and the process cartridges 7 according to the first embodiment. In the image forming apparatus 100 according to the third embodiment, the first and second electrodes 51 and 52 are arranged on the image forming apparatus 100, as illustrated in
In the image forming apparatus 100 according to the third embodiment, as in the image forming apparatus 100 according to the first embodiment, the process cartridges 7 are attachable to the image forming apparatus 100 and detachable therefrom. The first electrodes 51 (51Y to 51K) and the second electrodes 52 (52Y to 52K) are arranged on the main body of the image forming apparatus 100, not on the respective container main bodies 19. The individual first electrode 51 and the individual second electrode 52 are arranged on the image forming apparatus 100 in such a manner that the electrodes 51 and 52 sandwich a space in the corresponding recessed portion 18d. In this way, as in the first embodiment, whether the toner is present in the recessed portion 18d is detected by using the voltage based on the electrostatic capacitance between the corresponding first and second electrodes 51 and 52, and the amount of the toner in the corresponding container main body 19 is acquired.
As described above, as in the image forming apparatus 100 according to the first embodiment, the image forming apparatus 100 according to the third embodiment can accurately determine whether the individual developing unit 80 has been refilled with toner. As described above, in the image forming apparatus 100 according to the third embodiment, the first electrodes 51 and the second electrodes 52 are arranged on the apparatus main body of the image forming apparatus 100, not on the respective process cartridges 7. Thus, even when the process cartridge 7 is replaced, the corresponding first and second electrodes can be used without replacement. The image forming apparatus 100 according to the third embodiment has a fewer number of components of the individual process cartridge and refined recycling efficiency.
In each of the embodiments, the threshold is calculated by subtracting or adding a fixed value from or to the reference value. However, the fixed value is not necessarily a constant value. For example, the fixed value may be a value that changes depending on the number of rotations of the corresponding developing roller.
In each of the embodiments, the threshold is calculated by subtracting or adding a fixed value from or to the reference value. However, the threshold may also be calculated without using the fixed value. For example, the threshold may be obtained from a table about a correspondence relationship between an individual reference value and an individual threshold.
In addition, in each of the embodiments, a threshold is changed by using the maximum value or the minimum value of the voltage as the reference value. However, the threshold may be calculated in another way. For example, the CPU 420 may calculate the threshold from an average value of voltages in a time duration in which acquisition of the developer remaining amount is performed.
While the present disclosure has been described with reference to embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2018-014815, filed Jan. 31, 2018, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-014815 | Jan 2018 | JP | national |
