JP2002108085A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge the range of residue toner quantity detection and to improve resolution of the residue quantity of toner. SOLUTION: In the device, a developing AC frequency changeover device 1 which is connected to a developing bias generating device 167 and a CPU 165 is arranged and when a residue toner detail detection mode is selected by a user, the AC frequency of the developing bias that is generated by the developing bias generating device 167 is changed over. When the AC frequency is changed over, residue toner quantity detection resolution when the residue toner quantity is small is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic or electrostatic recording type image forming apparatus such as a copying machine or a printer, which is characterized by a developer remaining amount detecting device.

[0002]

2. Description of the Related Art A developer remaining amount detecting device in a conventional image forming apparatus will be described with reference to FIG.

A process cartridge 108 is detachably mounted on the image forming apparatus of this embodiment, and the process cartridge 108 is a photosensitive drum 10 which is an electrophotographic photosensitive member.
9, a charger 110 as a charging unit, a developing roller 111 as a voltage applying member, a toner storage unit 112 as a developer storage unit, a stirring bar 113 for stirring the developer (toner), a cleaning unit 114, and a waste toner container 115 is provided.

An antenna electrode 1 as a detection electrode is provided on a wall surface in the toner container 108 farthest from the developing roller 111.
51, and the antenna electrode 151 and the developing roller 111 acting as an electrode
2 respectively. Capacitance detection means 152
Detects the remaining amount of toner according to the detected capacitance by detecting the capacitance between the electrodes 111 and 151.

A high voltage power supply 166 is connected to the developing roller 111.
Is connected to a developing bias generator 167 as a voltage generator.

[0006] The capacitance detecting means 152 includes a developing roller 1
11 connected to reference capacitor 153, diode 1
54, 155, constant voltage source 156, reference voltage detection resistor 15
7, a reference voltage detection capacitor 158, diodes 159 and 160 connected to the antenna electrode 151, an antenna electrode output voltage resistor 161, an antenna electrode output voltage detection capacitor 162, and an operational amplifier 163.

[0007] The capacitance detecting means 152 is connected to the CPU 165 in the controller 101.

In the toner remaining amount detecting operation of the developer remaining amount detecting device having the above-described structure, first, a developing bias in which an AC voltage is superimposed on a DC voltage is generated in a developing bias generator 167. The developing bias is applied to the reference capacitor 153 in the capacitance detecting unit 152 and the developing roller 11.
1 is applied.

The reference capacitor 153 generates an alternating current according to the reference capacitor capacitance Cr. On the other hand, an alternating current corresponding to the capacitance Ct between the developing roller 111 and the antenna electrode 151 is generated at the antenna electrode 151.

The AC current flowing through the reference capacitor 153 is supplied to a reference voltage detection resistor 157 via a diode 154.
And rectified by the reference voltage detection capacitor 158 and converted into a DC voltage Vr1. Here, the DC voltage Vr2 (= 4.5) of the constant voltage source 156 is applied to the positive input of the operational amplifier 163.
V) and the DC voltage Vr1 are input as a voltage Vr.

On the other hand, the alternating current flowing through the antenna electrode 151 is supplied to the antenna electrode output voltage resistor 161 and the antenna electrode output voltage detection capacitor 1 via the diode 159.
It is rectified at 62 and converted into a DC voltage,
3 is input to the negative input.

With the above circuit configuration, the operational amplifier 1
63 outputs a voltage corresponding to the difference between the capacitance Cr of the reference capacitor 153 and the capacitance Ct between the developing roller 111 and the antenna electrode 151. Here, the operational amplifier 163
Output voltage Vs has a characteristic expressed by the following equation 1.

Vs = 4.5−A × (Ct−Cr) × f × Vpp (1) where A is a predetermined constant, Ct is a capacitance between the developing roller 111 and the antenna electrode 151, and Cr is a reference capacitor. 1
53 is the capacitance, f is the AC frequency of the developing bias, Vp
p is the peak-to-peak voltage of the developing bias.

An output voltage Vs (hereinafter, referred to as an output voltage Vs) is connected to a diode 164 connected to the output terminal of the operational amplifier 163.
The “capacitance detection voltage Vs” is suppressed to be equal to or less than the input rated voltage of the CPU 165.

FIG. 17 shows the relationship between the capacitance Ct between the developing roller 111 and the antenna electrode 151 and the capacitance detection voltage Vs.

Ce is the capacitance between the developing roller 111 and the antenna electrode 151 when the toner is empty (Empty);
Cf is the capacitance between the developing roller 111 and the antenna electrode 151 when the toner is full, and Cr
= Ce.

Since the toner as a developer has a higher dielectric constant than air, the developing roller 111 and the antenna electrode 151
The more toner is distributed between the developing rollers 111,
The capacitance Ct between the antenna electrodes 151 increases,
The capacitance detection voltage Vs decreases. Thus, the remaining amount of toner can be detected by detecting the capacitance detection voltage Vs.

FIG. 18 shows a flowchart of a conventional toner remaining amount detection.

First, when image formation (printing) is started (S501), a developing bias is generated by the developing bias generator 167 under image forming conditions (S502). The capacitance detection voltage Vs is converted from analog to digital by the analog input unit of the CPU 165, and the CPU 165 detects the detection voltage Vs.
Is detected (S503). Storage device 1 by CPU 165
Based on the conversion table stored in 70, the detection voltage Vs is converted to the remaining amount of toner, and the remaining amount of toner is detected (S
505). The remaining amount of toner is displayed on a display unit (not shown) (S506).

[0020]

However, as described above, since the conventional toner remaining amount detection is performed only at the time of image formation, the developing bias conditions, for example, the AC frequency f and the AC peak-to-peak voltage Vpp are fixed. Becomes For this reason, there is a problem that the resolution of the remaining toner detection decreases when the detection range of the remaining toner is widened, and the detection range of the remaining toner decreases when the resolution of the remaining toner detection is improved.

Accordingly, an object of the present invention is to provide an image forming apparatus provided with a developer remaining amount detecting device capable of increasing the developer remaining amount detection range and improving the resolution of the developer remaining amount. It is.

[0022]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides:
A developer accommodating portion for accommodating the developer, voltage generating means for generating a voltage including at least an AC voltage component, at least one voltage applying member to which the voltage generated by the voltage generating means is applied, and at least one A detection electrode, and capacitance detection means for detecting a capacitance between the voltage applying member and the detection electrode, wherein the developer storage is performed based on a capacitance detection result of the capacitance detection means. An image forming apparatus for detecting a remaining amount of a developer in a unit and notifying the developer detection result, wherein at least one voltage setting condition to be applied to the voltage applying member is provided.

According to one embodiment of the present invention, at least one of the voltage setting conditions is a frequency. According to another embodiment, at least one of the voltage setting conditions is a peak-to-peak voltage of an AC voltage. According to another embodiment, the apparatus has at least two voltage setting conditions, and the at least two voltage setting conditions are a frequency and a peak-to-peak voltage of an AC voltage. According to another embodiment, at least one of the voltage applying members is a developing roller.

According to another aspect of the present invention, a developer accommodating portion for accommodating a developer, voltage generating means for generating a voltage including at least an AC voltage component, and a voltage generated by the voltage generating means are applied. At least one voltage application member, at least one detection electrode, and capacitance detection means for detecting a capacitance between the voltage application member and the detection electrode, wherein the capacitance detection means In the image forming apparatus for detecting the remaining amount of the developer in the developer accommodating section based on the result of detecting the capacitance and notifying the result of the detection of the developer, at least one voltage setting condition to be applied to the voltage applying member is provided. An image forming apparatus is provided, wherein the voltage setting condition is switched under at least one switching condition.

According to one embodiment of the present invention, the switching condition is an external command. According to another embodiment, the switching condition is a remaining amount of the developer. According to another embodiment, the switching condition is the number of times of image formation. According to another embodiment, the switching condition is at least one of an external command, a remaining amount of the developer, and the number of times of image formation.

According to another embodiment, at least one of a combination of a voltage setting condition for applying a voltage to the voltage applying member and a switching condition for switching the voltage setting condition is a developer remaining amount. This is a combination of conditions specialized for detection.

According to another embodiment, at least one of a combination of a voltage setting condition for applying a voltage to the voltage applying member and a switching condition for switching the voltage setting condition involves image formation. There is no combination of conditions.

According to another embodiment, there is provided a cartridge having at least an electrophotographic photosensitive member and a developing means, the cartridge being detachably mounted on the apparatus main body, and the developer accommodating portion is included in the developing means.

According to another aspect of the present invention, a plurality of image carriers, a developer accommodating portion arranged corresponding to each of the image carriers and accommodating a developer, and at least one voltage to which a voltage is applied are provided. An applying member, a plurality of developing units including at least one detection electrode, a voltage generating unit including at least an AC voltage component, and generating a voltage applied to the voltage applying member, and a voltage generator between the voltage applying member and the detection electrode. And detecting the remaining amount of the developer in the developer accommodating portion based on the capacitance detection result of the capacitance detecting means. An image forming apparatus that reports a result has at least one voltage setting condition of a voltage applied to the voltage applying member.

According to another aspect of the present invention, there is provided an image carrier,
A plurality of developing means including a developer accommodating portion arranged around the image carrier and accommodating a developer, at least one voltage application member to which a voltage is applied, and at least one detection electrode; and at least an AC voltage component And a voltage generating means for generating a voltage applied to the voltage applying member, and a capacitance detecting means for detecting a capacitance between the voltage applying member and the detection electrode, wherein the capacitance A voltage setting condition of a voltage applied to the voltage applying member in an image forming apparatus that detects a remaining amount of the developer in the developer accommodating section based on a capacitance detection result of a detection unit and notifies the developer detection result. An image forming apparatus having at least one is provided.

According to one embodiment of the present invention, a combination of a voltage setting condition for applying a voltage to the voltage applying unit and a switching condition for switching the voltage setting condition is different for each color.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to the present invention will be described in more detail with reference to the drawings. The same members as those described above are denoted by the same reference numerals, and description thereof will be omitted.

Embodiment 1 A first embodiment of the present invention will be described with reference to FIGS.

First, the image forming apparatus of this embodiment will be described with reference to FIG.

Laser Printer 100 as Image Forming Apparatus
Includes a controller 101 and a laser unit 102 that emits a laser beam L on / off modulated by an image signal sent from the controller 101.
The laser unit 102 detects a polygon mirror 103 for horizontally scanning the laser beam L, a scanner motor 104 for rotating the polygon mirror 103 at a constant speed, an fθ lens 105 for forming an image of the laser beam L, and a BD signal indicating a horizontal scanning start point. And a reflection mirror 107 that reflects the laser light L.

A process cartridge 108 is removably mounted on the laser printer 100 via mounting means 130. The process cartridge 108 includes a photosensitive drum 109 as an electrophotographic photosensitive member, a charger 110 as a charging unit, a developing unit, a cleaning unit 114, and a waste toner container 115. In this embodiment, the developing means includes a developing roller 111 serving as a voltage applying member, a toner containing unit 112 serving as a developer containing unit, and a developer (toner).
And a stirring bar 113 for stirring the mixture.

The laser printer 100 further includes a cassette 116 and a cassette 11 for accommodating recording paper as a recording medium.
6 includes paper feed rollers 118 and 119 for feeding recording paper to the process cartridge 108, registration rollers 120 and 121, a transfer roller 122, a fixing device 123, and paper discharge rollers 124 and 125.

Next, the image forming operation will be described.

The controller 101 transmits an image signal to the scanner unit 102 based on the BD signal detected by the photodetector 106. The scanner unit 102 generates a laser beam L based on an image signal. The laser light L is applied to the polygon mirror 103, the fθ lens 105, the reflection mirror 1
07, the photosensitive drum 109 is charged on the photosensitive drum 109 charged to a predetermined voltage by the charger 110, and the photosensitive drum 10
A latent image based on the image signal is formed on the image 9. The latent image formed on the photosensitive drum 109 is developed by the developing roller 111 as a toner image.

On the other hand, the recording paper accommodated in the cassette 116 is picked up by a pickup roller 117 at a predetermined timing.
And the paper is fed up to the position just before the registration rollers 120 and 121 by the paper feed rollers 118 and 119, and temporarily stops. Thereafter, the paper is re-fed to the transfer section formed by the photosensitive drum 109 and the transfer roller 122 by the registration rollers 120 and 121 at a predetermined timing. In this transfer section, the transfer roller 122
The toner image on the photosensitive drum 109 is transferred to the recording paper by the action of.

The recording paper is conveyed to the fixing device 123, and the toner image is fused to the recording paper by pressure and heat to form a permanent image. Thereafter, the recording paper is discharged outside the laser printer 100 by the discharge rollers 124 and 125. After the transfer, the toner remaining on the photosensitive drum 109 is removed by the cleaning unit 114 and stored in the waste toner container 115.

Next, the developer remaining amount detecting device of this embodiment will be described with reference to FIG. Note that the developer remaining amount detection device of this embodiment has the same basic configuration as the conventional device described with reference to FIG. 14, and therefore only different portions will be described.

The developer remaining amount detecting device of this embodiment has a toner remaining amount detail detecting mode which can be set by a user. Therefore, as shown in FIG.
6 and a developing AC frequency switching device 1 connected to a developing bias generator 167 and a CPU 165 in the controller 101.

When the user selects the toner remaining amount detailed detection mode as a switching condition, that is, the developing AC frequency switching device 1 changes the AC frequency of the developing bias generated by the developing bias generator 167 according to an external command. Switch as voltage setting condition.

FIG. 3 shows the relationship between the remaining amount of toner and the capacitance detection voltage Vs when the AC frequency of the developing bias is switched.

A1 is an AC frequency fsp under image forming conditions.
This is the relationship between the remaining toner amount and the capacitance detection voltage Vs at the print, and the relationship between the remaining toner amount and the capacitance detection voltage Vs when B1 switches the AC frequency to the toner remaining amount detailed detection frequency f1. is there.

By switching the AC frequency to the toner remaining amount detail detection frequency f1, the resolution of detecting the remaining amount of toner when the amount of remaining toner is small is improved. Vth1 is a threshold voltage for determining whether to switch the AC frequency when the user selects the toner remaining amount detailed detection mode.

Next, the flow of toner remaining amount detection in this embodiment will be described with reference to the flowchart of FIG.

When image formation (printing) is started (S
1) First, a developing bias under image forming conditions is generated by the developing bias generator 167 (S2). The capacitance detection voltage Vs is converted from analog to digital by the analog input unit of the CPU 165, and the detection voltage Vsprint is detected (S3). Next, it is determined whether the user has selected the toner remaining amount detailed detection mode (S4).

When the detailed toner remaining amount detection mode is not selected, the CPU 165 detects the detection voltage Vsprint based on the conversion table stored in the storage device 170.
Is converted into the remaining amount of toner (S6), the remaining amount of toner is detected (S7), and the detection result is reported to, for example, the display unit 140 of the printer body (S8).

On the other hand, when the toner remaining amount detailed detection mode is selected in step S4, the detection voltage Vspr
The magnitude relationship between int and the threshold voltage Vth1 is determined.

When Vsprint ≦ Vth1, the CPU
165 converts the detection voltage Vsprint into a remaining toner amount based on the conversion table stored in the storage device 170 (S6), detects the remaining toner amount (S7), and notifies the display unit 140 of the detection result, for example. (S8).

When Vsprint> Vth1, after the completion of image formation, the developing AC is switched to f1 to generate a developing bias. At this time, no image formation is performed. Then, the CPU 165 detects the capacitance detection voltage Vs1 (S10), converts the detection voltage Vs1 to the remaining amount of toner based on the conversion table stored in the storage device 170 (S11), and detects the remaining amount of toner. Then (S7), for example, the detection result is notified to the display unit 140 (S8).

As described above, according to the present embodiment, the AC frequency of the developing bias is switched between two stages to detect the remaining amount of toner, and the remaining amount of toner can be detected other than during image formation. The detection range of the remaining amount of toner can be widened, and the resolution of the remaining amount of toner can be improved.

In the present embodiment, the description has been made of the configuration in which the remaining amount of toner is detected by switching the AC frequency of the developing bias to two stages. However, the AC frequency switching stage of the developing bias is not limited to two stages. It is also possible to switch to two or more stages.

In this embodiment, first, an image is formed, and based on the capacitance detection voltage Vs detected there,
Although the configuration in which the AC frequency switching of the developing bias is determined has been described, the AC frequency switching determination of the developing bias is determined based on the capacitance detection voltage Vs at the time of past image formation stored in a memory (not shown). It may be configured.

Embodiment 2 Next, a second embodiment of the present invention will be described with reference to FIGS. Note that the basic configuration of detecting the remaining amount of toner in the present embodiment is the same as that of the first embodiment, and a description thereof will be omitted, and different portions will be described.

In this embodiment, when the remaining amount of toner is equal to or less than the predetermined amount, the AC frequency of the developing bias is switched every predetermined number of image formations to detect the remaining amount of toner. Hereinafter, a range in which the remaining amount of toner is equal to or less than a predetermined remaining amount is referred to as a “detailed detection range”. Here, the switching condition of the AC frequency is the remaining amount of toner and the number of times of image formation.

FIG. 5 shows the relationship between the remaining amount of toner and the capacitance detection voltage Vs when the AC frequency of the developing bias is switched. A2 is the relationship between the remaining amount of toner at the AC frequency under the image forming conditions and the capacitance detection voltage Vs, and B2 is the remaining amount of toner and the capacitance when the AC frequency is switched to the toner remaining amount detail detection frequency f2. This is a relationship with the detection voltage Vs.

By switching the AC frequency to the toner remaining amount detail detection frequency f2, the resolution of the remaining amount of toner when the amount of remaining toner is small is improved. Vth2 is a threshold voltage for determining whether the remaining amount of toner is within the detailed detection range.

The flow of the toner remaining amount detection in this embodiment will be described with reference to the flowchart of FIG.

When image formation is started (S51), first, a developing bias under the image forming conditions is generated by the developing bias generator 167 (S52). When the capacitance detection voltage Vs is C
The analog / digital conversion is performed by the analog input unit of the PU 165, and the detection voltage Vsprint is detected (S53).
Next, it is determined whether or not the detection voltage Vsprint is within the detailed detection range (Vsprint> Vth2) (S5).
4).

If it is not within the detailed detection range, the CPU 165
Converts the detected voltage Vsprint into the remaining amount of toner based on the conversion table stored in the storage device 170 (S
57), the remaining amount of toner is detected (S58), and the detection result is reported to, for example, the display unit 140 (S59).

On the other hand, in step S54, the detection voltage Vsp
If it is determined that print is within the detailed detection range,
The magnitude relationship between the number of image formations N and the threshold number of times Nth is determined (S55).

If N ≦ Nth, 1 is added to the number of times N of image formation (S56). Then, the CPU 165 stores the storage device 1
The detection voltage Vsprint is converted into the remaining amount of toner based on the conversion table stored in 70 (S57), and the remaining amount of toner is detected (S58). For example, the detection result is notified to the display unit 140 (S59).

On the other hand, if N> Nth, after completion of image formation, the developing AC frequency is switched to f2 to generate a developing bias (S60). At this time, no image formation is performed. Then, the CPU 165 detects the capacitance detection voltage Vs2.
Is detected (S61), and the detection voltage Vs2 is converted into the remaining toner amount based on the conversion table stored in the storage device 170 (S62). Then, the image forming frequency N is cleared (S63), the remaining amount of toner is detected (S58), and the detection result is reported to, for example, the display unit 140 (S59).

As described above, according to the present embodiment, when the remaining amount of toner is equal to or less than the predetermined remaining amount, every predetermined number of image formations,
By switching the AC frequency of the developing bias to two stages to detect the remaining amount of toner and to enable the remaining amount of toner to be detected other than at the time of image formation, the detection range of the remaining amount of toner can be widened, and the remaining amount of toner can be detected. Resolution can also be improved.

In this embodiment, the description has been given of the configuration in which the AC frequency of the developing bias is switched to two steps to detect the remaining amount of toner. However, the switching step of the AC frequency of the developing bias is not limited to two steps. It is also possible to switch to two or more stages.

In this embodiment, an image is formed first, and based on the capacitance detection voltage Vs detected there,
Although the configuration in which the AC frequency switching of the developing bias is determined has been described, the AC frequency switching determination of the developing bias is determined based on the capacitance detection voltage Vs at the time of past image formation stored in a memory (not shown). It may be configured.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to FIGS. Note that the basic configuration of this embodiment is the same as that of the first embodiment, and therefore, different parts will be described. The present embodiment is characterized in that a peak-to-peak voltage of the developing AC voltage is switched as a voltage setting condition instead of the developing AC frequency in the first embodiment.

As shown in FIG. 7, the developer remaining amount detecting device of this embodiment includes the developing AC voltage switching device 51 in the high voltage power supply 166, and is used when the user selects the toner remaining amount detailed detection mode. The developing AC voltage (peak-to-peak voltage) of the developing bias generated by the developing bias generator 167 is switched.

FIG. 8 shows the relationship between the remaining amount of toner and the capacitance detection voltage Vs when the AC voltage of the developing bias is switched. A3 is the AC voltage Vppprin under image forming conditions.
In the relationship between the remaining amount of toner at t and the capacitance detection Vs,
B3 is the relationship between the remaining toner amount and the capacitance detection voltage Vs when the AC voltage is switched to the remaining toner amount detail detection voltage Vpp3. The AC voltage is a voltage V for detecting the remaining amount of toner.
By switching to pp3, the resolution of detecting the remaining amount of toner when the amount of remaining toner is small is improved. Vth3 is a threshold voltage for determining whether to switch the AC voltage when the user selects the toner remaining amount detailed detection mode.

Next, the flow of toner remaining amount detection in this embodiment will be described with reference to the flowchart of FIG.

When image formation is started (S101), first, a developing bias under image forming conditions is generated by the developing bias generator 167 (S102). Capacitance detection voltage Vs
Are converted from analog to digital by the analog input section of the CPU 165 to detect the detection voltage Vsprint (S10).
3). Next, it is determined whether the user has selected the toner remaining amount detail detection mode (S104).

When the detailed toner remaining amount detection mode is not selected, the CPU 165 detects the detection voltage Vsprint based on the conversion table stored in the storage device 170.
Is converted to the remaining amount of toner (S106), the remaining amount of toner is detected (S107), and the detection result is reported to, for example, the display unit 140 (S108).

On the other hand, if the toner remaining amount detailed detection mode is selected in step S104, the detection voltage Vs
A magnitude relationship between print and the threshold voltage Vth3 is determined (S104).

If Vsprint ≦ Vth3, the CPU
165 converts the detection voltage Vsprint into the remaining amount of toner based on the conversion table stored in the storage device 170 (S106), detects the remaining amount of toner (S107),
For example, the detection result is notified to the display unit 140 (S10
8).

When Vsprint> Vth3, after the image formation is completed, the developing AC voltage is switched to Vpp1 to generate a developing bias. At this time, no image formation is performed.
Then, the CPU 165 detects the capacitance detection voltage Vs3 (S110), converts the detection voltage Vs2 to the remaining amount of toner based on the conversion table stored in the storage device 170 (S111), and detects the remaining amount of toner. Do (S10
7) For example, the detection result is notified to the display unit 140 (S1).
08).

As described above, according to the present embodiment, the remaining amount of toner is detected by switching the developing AC voltage of the developing bias to two stages, and the remaining amount of toner can be detected other than during image formation. Accordingly, the detection range of the remaining amount of toner can be widened, and the resolution of the remaining amount of toner can be improved.

In this embodiment, the description has been given of the configuration in which the AC voltage of the developing bias is switched in two stages to detect the remaining amount of toner. However, the AC voltage switching stage of the developing bias is not limited to two stages. It is also possible to switch to two or more stages.

In this embodiment, first, an image is formed, and based on the capacitance detection voltage Vs detected there,
Although the configuration in which the determination of the switching of the developing bias AC voltage is performed has been described, the determination of the switching of the developing bias AC voltage is determined based on the capacitance detection voltage Vs at the time of past image formation stored in the memory (not shown). It may be configured.

Embodiment 4 Next, a fourth embodiment of the present invention will be described with reference to FIGS. Note that the basic configuration of the remaining toner amount detection in the present embodiment is the same as that of the third embodiment, and a description thereof will be omitted, and different portions will be described.

In the present embodiment, when the remaining amount of toner is equal to or less than the predetermined amount, the alternating voltage of the developing bias is switched every predetermined number of image formations to detect the remaining amount of toner. Hereinafter, a range in which the remaining amount of toner is equal to or less than a predetermined remaining amount is referred to as a “detailed detection range”.

FIG. 10 shows the relationship between the remaining amount of toner and the capacitance detection voltage Vs when the AC voltage of the developing bias is switched. A4 is the relationship between the remaining amount of toner at the AC frequency under the image forming conditions and the capacitance detection voltage Vs, and B4 is the remaining amount of toner and the capacitance when the AC voltage is switched to the toner remaining amount detailed detection voltage Vpp4. This is a relationship with the detection voltage Vs.

The AC voltage is converted to the toner remaining amount detecting voltage Vp.
By switching to p4, the resolution of the remaining amount of toner when the amount of remaining toner is small is improved. Vth4 is a threshold voltage for determining whether the remaining amount of toner is within the detailed detection range.

The flow of toner remaining amount detection in this embodiment will be described with reference to the flowchart of FIG.

When the image formation is started (S151), first, the developing bias of the image forming condition is generated by the developing bias generator 167 (S152). Capacitance detection voltage Vs
Are converted from analog to digital by the analog input unit of the CPU 165 to detect the detection voltage Vsprint (S15).
3). Next, it is determined whether the detection voltage Vsprint is within the detailed detection range (S154).

If it is not within the detailed detection range, the CPU 165
Converts the detected voltage Vsprint into the remaining amount of toner based on the conversion table stored in the storage device 170 (S
157), the remaining amount of toner is detected (S158), and the detection result is reported to, for example, the display unit 140 (S159).

On the other hand, in step S154, the detection voltage Vs
If it is determined that the print is within the detailed detection range, a magnitude relationship between the number of image formations N and the threshold number of times Nth is determined (S155).

If N ≦ Nth, 1 is added to the number N of image formations (S156). Then, the CPU 165 converts the detection voltage Vsprint into the remaining amount of toner based on the conversion table stored in the storage device 170 (S157),
The remaining amount of toner is detected (S58), and for example, the display unit 140
Is notified of the detection result (S159).

On the other hand, if N> Nth, after completion of image formation, the developing AC voltage is switched to Vpp4 to generate a developing bias (S160). At this time, no image formation is performed. Then, the CPU 165 detects the capacitance detection voltage Vs.
4 is detected (S161), and the detection voltage Vs4 is converted into the remaining amount of toner based on the conversion table stored in the storage device 170 (S162). Then, the image forming frequency N is cleared (S163), and the remaining amount of toner is detected (S15).
8) For example, the detection result is notified to the display unit 140 (S1).
59).

As described above, according to the present embodiment, when the remaining amount of toner is equal to or less than the predetermined remaining amount, every predetermined number of image formations,
The remaining amount of toner is detected by switching the AC voltage of the developing bias in two steps, and the remaining amount of toner can be detected other than at the time of image formation. Resolution can also be improved.

Although the present embodiment has been described with reference to the configuration in which the AC voltage of the developing bias is switched in two stages to detect the remaining amount of toner, the AC voltage switching stage of the developing bias is limited to two stages. Instead, it may be switched to two or more stages.

According to the present invention described with reference to each of the first to fourth embodiments, the amount of the remaining developer can be sequentially detected with high accuracy.

As described above, the developer remaining amount information from the developer remaining amount detecting device is displayed on the display unit 1 at the top of the image forming apparatus main body.
40 or on a terminal screen of a user's personal computer or the like as shown in FIGS. FIG.
13 and FIG. 13, the user is notified of the amount of the developer based on which part of the gauge 52 the needle 51 that moves according to the amount of the developer is pointing.

In each of the embodiments described above, the configuration has been described in which the remaining amount of toner is detected by one antenna electrode and the developing roller. However, the configuration may be such that the remaining amount of toner is detected by a plurality of antenna electrodes.

Further, in each of the above embodiments, the configuration in which the antenna electrode is disposed inside the process cartridge has been described.
It may be configured to be arranged in a place other than the process cartridge.

Further, in each of the above embodiments, the configuration of the process cartridge type image forming apparatus has been described. However, the developer remaining amount detecting device according to the present invention is not limited to the process cartridge type image forming apparatus. The present invention is also applicable to a toner supply type image forming apparatus.

Embodiment 5 Next, a fifth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the developer remaining amount detection device described in each of the above embodiments is applied to a multicolor image forming apparatus, and a detailed description thereof will be omitted, and the above description will be referred to.

As shown in FIG. 14, the multicolor image forming apparatus of this embodiment is a full-color image forming apparatus, and includes black Bk, cyan C, magenta M, and yellow Y image forming units I, II, III, A configuration is provided in which the IVs are juxtaposed along the endless transport belt 3. The transport belt 3 is stretched around a drive roller 4 connected to a drive unit composed of a motor and gears (not shown) and a driven roller 5 that applies a constant tension to the transport belt 3.

Each of the image forming units I, II, III, and IV has the same configuration, and includes a photosensitive drum 1a, 1b, 1c, 1d, and a photosensitive drum 1a as image carriers for forming an electrostatic latent image. , 1b, 1c, and 1d for uniformly charging the photosensitive drums 1a, 1b, 1c, and 1d by performing exposure in accordance with image information. Laser scanners 2a, 2b, 2
c, 2d, developing device 2 for developing electrostatic latent image with toner
5a, 25b, 25c, 25d, and photosensitive drum 1
Cleaning device 2 for cleaning a, 1b, 1c, 1d
6a, 26b, 26c, and 26d.

The photosensitive drums 1a to 1d, the charging device 2
Each of the developing devices 4a to 24d, the developing devices 25a to 25d, and the cleaning devices 26a to 26d is integrally formed as a cartridge, and is detachably attached to the apparatus main body.

In this embodiment, although not shown in FIG.
The developing bias generator 167 described in the above embodiment,
And the capacitance detecting means 152 is connected to each of the image forming units I, II, and II.
I and IV respectively.

In the above configuration, when data to be printed is sent from the computer to the printer, and the image formation in accordance with the printer engine system is completed and the printer is ready for printing, the recording material P is supplied from a paper cassette (not shown). The recording material P is sequentially conveyed to the image forming units I, II, III, and IV of each color by the conveyance belt 3. The image signals of the respective colors are transmitted to the respective laser scanners 2 in synchronization with the conveyance of the recording material P by the conveyance belt 3.
a, 2b, 2c, and 2d, and the charging devices 24a, 24
An electrostatic latent image is formed on the photosensitive drums 1a, 1b, 1c, and 1d uniformly charged by b, 24c, and 24d.
The electrostatic latent images are developed as toner images by the developing devices 25a, 25b, 25c and 25d, and the toner images are sequentially transferred onto the recording material P by the transfer devices 27a, 27b, 27c and 27d. In FIG. 14, images are sequentially formed in the order of Y, M, C, and Bk. Thereafter, the recording material P is separated from the transport belt 3 and transported to the fixing device 28, where the unfixed toner image is fixed on the recording material P.

After the transfer, each photosensitive drum 1a, 1b, 1
c, the toner remaining on 1d is the cleaning device 26a,
It is removed by 26b, 26c, 26d.

In each image forming section, the first embodiment is used.
The remaining toner amount is detected by the methods described in (1) to (4).

In this case, the combination of the condition for executing the detailed detection of the remaining amount of toner and the voltage setting condition at the time of performing the detailed detection of the remaining amount of toner may be set to be different for each color.

For example, the remaining toner amount for executing the detailed detection of the remaining amount of toner and the frequency at the time of executing the detailed detection may be set to be different for each color.

In this embodiment, each of the image forming units I, II, II
Although the toner images of each color formed in I and IV are directly transferred to the recording material P carried on the conveyor belt 3, the toner images of each color formed in the image forming units I, II, III and IV Of course, the present invention can be applied to an intermediate transfer type multi-color image forming apparatus in which is temporarily transferred to an intermediate transfer body and further transferred to recording paper.

In this embodiment, the same operation and effect as those of the above embodiment can be obtained.

Embodiment 6 Next, a sixth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the developer remaining amount detection device described in each of the above embodiments is applied to a multi-color (two-color) image forming apparatus, and a detailed description thereof will be omitted, and the above description will be used.

In the multicolor image forming apparatus of this embodiment, when the photosensitive drum 30 is uniformly charged by the charging device 31, a latent image corresponding to image information is formed by light from the exposing device 32. Next, the latent image is developed by, for example, red toner by the first developing device 33 to form a red toner image. Next, the photosensitive drum 30 is exposed by the exposure device 32b to form a latent image, and is developed by, for example, black toner by the second developing device 34 to form a two-color toner image on the photosensitive drum 30. Next, the two-color toner image is fed to the fed recording paper 35.
Is transferred by the transfer device 36, and is fixed by heat and pressure by the fixing device 37. After the transfer, the photosensitive drum 30
It is cleaned by the cleaning device 38 and is used for the next image formation.

In each of the developing devices, the first embodiment was used.
5, the remaining amount of toner is detected.

In this embodiment, the colors of the toners of the first and second developing devices are red and black, but of course, other colors may be used.

Further, in the present embodiment, similarly to the fifth embodiment, the combination of the condition for executing the detailed detection of the remaining amount of toner and the voltage setting condition at the time of executing the detailed detection of the remaining amount of toner is different for each color. May be set.

In this embodiment, the same operation and effect as in the above embodiment can be obtained.

[0117]

As is clear from the above description, the image forming apparatus of the present invention has at least one voltage setting condition applied to the voltage applying member, or has the voltage setting condition applied to the voltage applying member. By switching the voltage setting condition under at least one switching condition, the developer remaining amount detection range can be widened, the resolution of the developer remaining amount can be improved, and the developer remaining amount can be improved. The amount can be detected over a wide range and accurately.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a circuit diagram of a developer remaining amount detecting device according to the first embodiment.

FIG. 3 is a graph showing a relationship between a remaining toner amount and a detection voltage in the first embodiment.

FIG. 4 is a flowchart of a toner remaining amount detection in the first embodiment.

FIG. 5 is a graph showing a relationship between a remaining toner amount and a detection voltage in the second embodiment.

FIG. 6 is a flowchart of a process for detecting the remaining amount of toner in the second embodiment.

FIG. 7 is a circuit diagram of a developer remaining amount detecting device according to a third embodiment.

FIG. 8 is a graph showing a relationship between a remaining amount of toner and a detection voltage in the third embodiment.

FIG. 9 is a flowchart for detecting the remaining amount of toner in the third embodiment.

FIG. 10 is a graph showing a relationship between a remaining toner amount and a detection voltage in the fourth embodiment.

FIG. 11 is a flowchart of a toner remaining amount detection in a fourth embodiment.

FIG. 12 is a diagram illustrating an example of a developer remaining amount display.

FIG. 13 is a view showing another embodiment of the developer remaining amount display.

FIG. 14 is a configuration diagram illustrating a multicolor image forming apparatus according to a fifth embodiment.

FIG. 15 is a configuration diagram illustrating a multicolor image forming apparatus according to a sixth embodiment.

FIG. 16 is a circuit diagram showing a developer remaining amount detecting device in a conventional example.

FIG. 17 is a graph showing a relationship between a remaining amount of toner and a detection voltage in a conventional example.

FIG. 18 is a flowchart of a toner remaining amount detection in a conventional example.

[Explanation of symbols]

108 Process cartridge 111 Developing roller (voltage applying member) 112 Toner container (developer accommodating section) 152 Capacitance detecting means 167 Developing bias generator (voltage generating means)

Claims (28)

[Claims] 1. A developer accommodating section for accommodating a developer, voltage generating means for generating a voltage including at least an AC voltage component, and at least one voltage applying member to which the voltage generated by the voltage generating means is applied. And at least one detection electrode, and capacitance detection means for detecting capacitance between the voltage applying member and the detection electrode, based on a capacitance detection result of the capacitance detection means. An image forming apparatus that detects the remaining amount of the developer in the developer accommodating section and notifies the developer detection result, wherein at least one voltage setting condition of a voltage applied to the voltage applying member is provided. Image forming device. 2. The image forming apparatus according to claim 1, wherein at least one of the voltage setting conditions is a frequency. 3. The image forming apparatus according to claim 1, wherein at least one of the voltage setting conditions is a peak-to-peak voltage of an AC voltage. 4. At least two voltage setting conditions, wherein the at least two voltage setting conditions are frequency,
2. The image forming apparatus according to claim 1, wherein the AC voltage is a peak-to-peak voltage. 5. At least one of said voltage applying members,
5. The image forming apparatus according to claim 1, wherein the image forming apparatus is a developing roller. 6. A developer accommodating portion for accommodating a developer, voltage generating means for generating a voltage including at least an AC voltage component, and at least one voltage applying member to which the voltage generated by the voltage generating means is applied. And at least one detection electrode, and capacitance detection means for detecting capacitance between the voltage applying member and the detection electrode, based on a capacitance detection result of the capacitance detection means. In the image forming apparatus for detecting the remaining amount of the developer in the developer accommodating portion and notifying the developer detection result, the image forming apparatus has at least one voltage setting condition of a voltage applied to the voltage applying member, and has at least one An image forming apparatus, wherein the voltage setting condition is switched according to a switching condition. 7. The image forming apparatus according to claim 6, wherein the switching condition is an external command. 8. The image forming apparatus according to claim 6, wherein the switching condition is a remaining amount of the developer. 9. The image forming apparatus according to claim 6, wherein the switching condition is a number of times of image formation. 10. The image forming apparatus according to claim 6, wherein the switching condition is at least one of an external command, a remaining amount of the developer, and the number of times of image formation. 11. A combination of a voltage setting condition for applying a voltage to the voltage applying member and a switching condition for switching the voltage setting condition, at least one of the combinations is dedicated to developer remaining amount detection. The image forming apparatus according to claim 6, wherein the image forming apparatus is a combination of the following conditions. 12. A combination of a voltage setting condition for applying a voltage to the voltage applying member and a switching condition for switching the voltage setting condition, wherein at least one combination is a combination of conditions without image formation. The image forming apparatus according to claim 6, wherein: 13. The image forming apparatus according to claim 1, further comprising a cartridge having at least an electrophotographic photosensitive member and a developing unit, wherein the cartridge is detachably mounted on the apparatus main body, and the developer accommodating unit is included in the developing unit. 13. The image forming apparatus according to any one of 1 to 12. 14. A plurality of image carriers, a developer accommodating portion arranged corresponding to each image carrier and accommodating a developer, at least one voltage applying member to which a voltage is applied, and at least one voltage applying member. Developing means including a detecting electrode; voltage generating means including at least an AC voltage component and generating a voltage applied to the voltage applying member; and electrostatic detecting a capacitance between the voltage applying member and the detecting electrode. An image forming apparatus comprising: a capacitance detecting unit, which performs developer remaining amount detection in the developer accommodating portion based on a capacitance detection result of the capacitance detecting unit, and notifies the developer detection result. An image forming apparatus having at least one voltage setting condition for a voltage applied to the voltage applying member. 15. An image carrier, comprising: a developer accommodating portion disposed around the image carrier and accommodating a developer; at least one voltage application member to which a voltage is applied; and at least one detection electrode A plurality of developing units; a voltage generating unit that includes at least an AC voltage component and generates a voltage applied to the voltage applying member; and a capacitance detection unit that detects a capacitance between the voltage applying member and the detection electrode. Means for detecting the remaining amount of the developer in the developer accommodating portion based on the capacitance detection result of the capacitance detection means, and reporting the developer detection result. An image forming apparatus having at least one voltage setting condition of a voltage applied to an application member. 16. The image forming apparatus according to claim 14, wherein at least one of the voltage setting conditions is a frequency. 17. The image forming apparatus according to claim 14, wherein at least one of the voltage setting conditions is a peak-to-peak voltage of an AC voltage. 18. At least two voltage setting conditions, wherein the at least two voltage setting conditions are frequency,
16. The image forming apparatus according to claim 14, wherein the voltage is a peak-to-peak voltage of an AC voltage. 19. The image forming apparatus according to claim 14, wherein at least one of the voltage applying members is a developing roller. 20. A plurality of image carriers, a developer accommodating portion arranged corresponding to each of the image carriers and accommodating a developer, at least one voltage applying member to which a voltage is applied, and at least one voltage applying member. Developing means including a detection electrode, voltage generating means for generating a voltage including at least an AC voltage component,
A capacitance detecting unit that detects a capacitance between the voltage applying member and the detection electrode; and a developer remaining in the developer accommodating unit based on a capacitance detection result of the capacitance detecting unit. An image forming apparatus that performs an amount detection and notifies the developer detection result, comprising at least one voltage setting condition of a voltage applied to the voltage applying member, and switching the voltage setting condition by at least one switching condition. An image forming apparatus comprising: 21. An image carrier, comprising: a developer accommodating portion disposed around the image carrier and accommodating a developer; at least one voltage application member to which a voltage is applied; and at least one detection electrode A plurality of developing means, a voltage generating means for generating a voltage including at least an AC voltage component, and a capacitance detecting means for detecting a capacitance between the voltage applying member and the detection electrode; In the image forming apparatus, which detects the remaining amount of the developer in the developer accommodating portion based on the capacitance detection result of the capacitance detection means and notifies the developer detection result, the voltage of the voltage applied to the voltage applying member An image forming apparatus having at least one setting condition, wherein the voltage setting condition is switched according to at least one switching condition. 22. The image forming apparatus according to claim 20, wherein the switching condition is an external command. 23. The image forming apparatus according to claim 20, wherein the switching condition is a remaining amount of the developer. 24. The image forming apparatus according to claim 20, wherein the switching condition is a number of times of image formation. 25. The image forming apparatus according to claim 20, wherein the switching condition is at least one of an external command, a remaining amount of developer, and the number of times of image formation. 26. At least one of a combination of a voltage setting condition for applying a voltage to the voltage applying member and a switching condition for switching the voltage setting condition is specialized for detecting the remaining amount of the developer. The image forming apparatus according to any one of claims 20 to 25, wherein the combination is a combination of the following conditions. 27. At least one combination of a voltage setting condition for applying a voltage to the voltage applying member and a switching condition for switching the voltage setting condition is a combination of conditions without image formation. The image forming apparatus according to any one of claims 20 to 26, wherein: 28. The combination according to claim 20, wherein a combination of a voltage setting condition for applying a voltage to the voltage applying member and a switching condition for switching the voltage setting condition is different for each color. An image forming apparatus according to the item.