JP2007072123A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To discriminate whether or not a developing device is exactly set in an image forming apparatus, whether or not the seal of a developer cartridge set in the developing device is pulled out, and whether or not developer in the developing device is normally stirred by using a toner concentration sensor. <P>SOLUTION: The (n) toner concentration sensors 27-1 and the like as many as developing units provided in the image forming apparatus are connected to a control board 30. Since detected voltage Vt from the toner concentration sensor is pulled down by a resistance 31-1 or the like inside the control board 30, if the toner concentration sensor is not set, Vt=0 when it is viewed from the control board 30, whereby the toner concentration sensor, in other words, the developing device is not set is detected. The toner concentration sensor generates sensor output voltage different among when the seal of the developer cartridge is not pulled out, when it is pulled out and when the developer is normally stirred. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus using an electrophotographic process, and more specifically, whether or not the developing device is correctly set in the main body of the image forming device and whether or not the seal of the developer cartridge set in the developing device is pulled out. The present invention relates to an image forming apparatus capable of determining whether or not a developer in a developing device has been normally stirred.

  Image forming apparatuses (laser printers, copiers, facsimile machines, multi-function printers, etc.) that form images using an electrophotographic process are known. The electrophotographic process is to form an image through the following steps. First, a latent image carrier such as a photoconductor is exposed to form an electrostatic latent image, and negatively or positively charged toner is attached to the latent image and developed to obtain a visible image. Next, the visible image is transferred from the latent image carrier onto a transfer member such as transfer paper directly or via an intermediate transfer member, and then fixed on the transfer member by heating or the like.

  In a developing device provided in an image forming apparatus using such an electrophotographic process, a two-component developer in which toner particles and carrier particles are mixed is used. A developing unit comprising a developing device and a developer cartridge containing a two-component developer is shipped from the manufacturing factory in a state where it is mounted on the image forming apparatus main body, and through various means of transportation, the customer's office, factory, workplace Installed at home. At this time, the developer cartridge is mounted on the main body and shipped in a state of being sealed with a sealing material.

  The reason for this is to prevent a situation in which the two-component developer starts to spill out due to various vibrations and impacts during transportation and contaminates the inside of the image forming apparatus. That is, the developing unit has an opening for supplying toner from the developing roller to the photosensitive member, and the magnetic particles and the toner are exposed from the opening, so that vibration and impact are applied in this state. As a result, the exposed magnetic particles or toner starts to spill out and contaminate the inside of the image forming apparatus. In particular, since magnetic particles have conductivity, if they fall on a power supply device, a printed circuit board for control, etc., there is a risk that not only abnormal operation but also ignition and smoke problems may occur. As described above, when the spilling of the magnetic particles occurs, the image forming apparatus itself is often collected and discarded, and the loss is large. Therefore, the developer cartridge is shipped in a state where it is sealed with a sealant in a developer cartridge that contains an initial agent in which magnetic particles and toner are mixed so as not to reach the developing device.

  When unpacking and installing an image forming apparatus that has been shipped in this state and carried into an installation location, forgetting to remove the seal, which is a relatively simple task among various operations. There is. In addition, there are many cases where the user forgets to pull out the seal even when a new product is replaced due to the life of the developing device. The former is mostly performed by a dedicated serviceman, and the latter may be performed by the user in addition to the serviceman, so the incidence is overwhelmingly higher in the latter. Even if the machine running in the office or office has a downtime for the replacement work due to the life of the developer, if you forget to pull out the seal in the replacement work, further downtime will overlap, This can have a huge impact on the user.

Accordingly, in order to solve such problems, a cartridge that includes at least a developing unit and is supplied with a two-component developer from a developer preset seal when mounted on the image forming apparatus main body, and a two-component developer in the developing unit. Toner density detecting means for detecting the toner density of the developer, and toner density control means for controlling the toner density of the two-component developer in the developing section based on an output signal of the toner density detecting means, In an image forming apparatus that replaces a cartridge depending on its life, a new article detecting means for detecting that the cartridge is new, and an output value of the toner density detecting means after the new article detecting means detects that the cartridge is new. An image forming apparatus including a prohibiting unit that prohibits a predetermined operation (such as a copying operation) when the value is not equal to or greater than a certain value is proposed Are (see Patent Document 1). According to this image forming apparatus, if the user forgets to apply the two-component developer to the developing unit from the developer preset seal when the cartridge is attached to the image forming apparatus main body, the predetermined operation is prohibited and the user forgets the operation. It is possible to eliminate the occurrence of an abnormal image in the event of a failure.
JP-A-9-197788

However, the image forming apparatus does not disclose means for enabling confirmation that a new article replacement operation with the life of the developing device has been correctly performed. That is, in the case of a new product replacement operation accompanying the life of the developing device, first, a new developing device is mounted (set) on the image forming apparatus main body, then a new developer cartridge (toner cartridge) is mounted on the developing device, and then The procedure for pulling out the sealing material is executed. However, when these are performed by the user, it is not possible to determine whether or not the developing device is correctly attached to the main body of the image forming apparatus.
In the image forming apparatus, although the toner supply amount of the toner supply unit is controlled so that the developer concentration in the developing device is constant, it is detected whether the developer is normally stirred. Therefore, when an abnormality occurs in the agitation unit, the development is performed with a developer that is not sufficiently agitated, so that the image quality is deteriorated.

  The present invention has been made to solve such problems, and an object of the present invention is to determine whether or not the developing device is correctly attached to the main body of the image forming apparatus, and to seal the developer cartridge attached to the developing device. It is possible to determine whether or not the toner has been pulled out and whether or not the developer in the developing device has been normally stirred.

According to the first aspect of the present invention, a developer cartridge that contains a developer in which magnetic particles and toner are mixed at a predetermined ratio, and the developer cartridge is detachably mounted and supplied from the developer cartridge. A developer having a developer agitating function and detachably attached to the image forming apparatus, and a control provided in the developer for detecting the toner density in the developer and supplied from the control device A toner concentration sensor that outputs toner concentration data as a sensor output voltage value to the control device in response to the voltage; and a sensor output voltage value when a predetermined first control voltage is applied from the control device to the toner concentration sensor. And a first sensor corresponding to the first control voltage determined from the control voltage vs. sensor output voltage characteristics of the toner density sensor when the developer cartridge is not mounted. Based on the magnitude relationship between the output voltage, an image forming apparatus characterized by having a determining means for determining whether or not the developing device is mounted to the image forming apparatus main body.
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the toner density sensor has a storage unit that stores the first sensor output voltage, and the determination unit has a predetermined value in the toner density sensor. The image forming apparatus is characterized in that the sensor output voltage when the first control voltage is applied is compared with the first sensor output voltage stored in the storage means.
According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the first sensor output voltage stored in the storage unit is the same as that of the initial agent when the toner concentration sensor is manufactured. An image forming apparatus comprising: a sensor output voltage of the toner density sensor when the first control voltage is applied to the toner density sensor without mounting the inspection jig mixed with the toner density sensor. It is.
According to a fourth aspect of the present invention, in the image forming apparatus according to the first aspect, when it is determined that the developing device is attached to the main body of the image forming apparatus, the stirring operation of the magnetic particles and the toner is performed for a predetermined time. Means for executing, a sensor output voltage value when a predetermined second control voltage is applied from the control device to the toner density sensor after the stirring, and a control voltage pair of the toner density sensor when the developer cartridge is not mounted. Means for determining whether or not the sealing material of the developer cartridge has been pulled out based on the magnitude relationship with the second sensor output voltage corresponding to the second control voltage determined from the sensor output voltage characteristics; An image forming apparatus including the image forming apparatus.
According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the toner concentration sensor has a storage unit that stores the output voltage of the second sensor, and the determination unit has a predetermined value in the toner concentration sensor. The image forming apparatus is characterized in that the sensor output voltage when the second control voltage is applied is compared with the second sensor output voltage stored in the storage means.
According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, the second sensor output voltage stored in the storage means is the same as that of the initial agent when the toner concentration sensor is manufactured. An image forming apparatus characterized by a sensor output voltage of the toner density sensor when the second control voltage is applied to the toner density sensor without mounting the inspection jig mixed with the toner density sensor. It is.
According to a seventh aspect of the present invention, in the image forming apparatus according to the first aspect, when it is determined that the developing device is attached to the main body of the image forming apparatus, the stirring operation of the magnetic particles and the toner is performed for a predetermined time. Means for executing, a sensor output voltage value when a predetermined third control voltage is applied from the control device to the toner density sensor after the stirring, and a control voltage versus a sensor of the toner density sensor when the developer cartridge is mounted Means for determining whether or not the developer has been normally stirred based on a magnitude relationship with a third sensor output voltage corresponding to the third control voltage determined from an output voltage characteristic. An image forming apparatus.
According to an eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect, the toner density sensor has a storage unit for storing the third sensor output voltage, and the determination unit has a predetermined value for the toner density sensor. The image forming apparatus is characterized in that the sensor output voltage when the third control voltage is applied is compared with the third sensor output voltage stored in the storage means.
According to a ninth aspect of the present invention, in the image forming apparatus according to the eighth aspect, the third sensor output voltage stored in the storage means is the same as that of the initial agent when the toner concentration sensor is manufactured. An image forming apparatus characterized by a sensor output voltage of a toner density sensor when a test jig mixed with is attached to the toner density sensor and the third control voltage is applied to the toner density sensor. is there.
According to a tenth aspect of the present invention, in the image forming apparatus according to any one of the fourth to sixth aspects, the means for detecting whether or not the developing device is new, and the newness detected by the means are detected. And a control unit for operating a unit for executing the stirring operation for a predetermined time.
According to an eleventh aspect of the present invention, in the image forming apparatus according to any one of the second, fifth, and eighth aspects, the control voltage is a PWM signal that switches between high and low at a predetermined interval, and the storage unit is being accessed. Is an image forming apparatus characterized in that a PWM operation is not performed and a signal having only one of high and low voltages is used.
According to a twelfth aspect of the present invention, in the image forming apparatus according to any one of the second, fifth, and eighth aspects, the storage unit is not accessed during the toner concentration detection operation by the control voltage. Forming device.
According to a thirteenth aspect of the present invention, in the image forming apparatus according to the second, fifth, or eighth aspect, the image forming apparatus includes a toner density sensor corresponding to the number of developing units, and the data storage means is a non-volatile memory having an I ² C interface. The serial clock line and serial data line to the non-volatile memory are connected in a daisy chain format across a plurality of non-volatile memories, and any one of terminals to which a 3-bit address for selecting the non-volatile memory is supplied. The image forming apparatus is characterized in that the book is connected to the output terminal of the control voltage and the other is connected to GND or Vcc.
According to a fourteenth aspect of the present invention, in the image forming apparatus according to the thirteenth aspect, all of the plurality of toner density sensors have the same connection form of terminals to which a three-bit address for selecting the nonvolatile memory is supplied. The plurality of toner density sensors all have a common configuration.
According to a fifteenth aspect of the present invention, in the image forming apparatus according to the second, fifth, or eighth aspect, the data storage unit stores manufacturing information relating to a toner density sensor. .
According to a sixteenth aspect of the present invention, in the image forming apparatus according to the second, fifth or eighth aspect, the data storage unit is formed by combining the developing device and the toner density sensor. The image forming apparatus is characterized in that manufacturing information is stored.
The invention according to claim 17 is the image forming apparatus according to claim 2, 5 or 8, wherein the data storage means stores a use history of the image forming apparatus. .
According to an eighteenth aspect of the present invention, in the image forming apparatus according to the second, fifth, or eighth aspect, the data storage unit stores a use history of components mounted on the image forming apparatus. The image forming apparatus.

  According to the present invention, whether or not the developing device is correctly attached to the main body of the image forming apparatus, whether or not the seal material of the developer cartridge attached to the developing device has been pulled out, and the developer in the developing device is normal. It can be discriminated whether or not it is stirred.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing the configuration of the photosensitive unit 1 and the developing unit 2 in the image forming apparatus according to the embodiment of the present invention. As shown in this figure, the photosensitive unit 1 includes a photosensitive drum 11 as a latent image carrier, a charging roller 12, a charging roller cleaning brush 13, a cleaning blade 14, a cleaning brush 15, and a waste toner collecting coil 16. ing. The developing unit 2 includes a developer cartridge 21 containing a two-component developer (hereinafter referred to as developer) in which toner particles and carrier particles are mixed, a developing roller 23, a left conveying screw 24, and a right conveying screw. 25, a developing doctor 26, and a developing device 22 having a toner concentration sensor 27. Although not shown, the developer cartridge 21 has an opening for discharging the developer and a sealing material that covers the opening and seals the developer inside. It is configured to be detachable. The developing roller 23 includes a non-magnetic pipe 23a and a magnetic roller 23b disposed on the inner periphery thereof. The non-magnetic pipe 23a is driven to rotate by means not shown, and the magnetic roller 23b is fixed so as not to rotate. ing. The magnetic roller 23b has a plurality of magnetic poles arranged in the circumferential direction. The toner density sensor 27 is disposed on the side wall in the developing unit 22 and detects the apparent permeability due to the mixing ratio of the magnetic carrier and the non-magnetic toner, and converts the toner into an electric signal based on the detection signal from the inductance head. Detect the density of.

  The photosensitive drum 11 is driven to rotate clockwise in the drawing by a driving unit (not shown), and the charging roller 12 uniformly charges the surface of the photosensitive drum 11 to, for example, a negative polarity. The surface of the photosensitive drum 11 after the uniform charging is irradiated with a laser beam L emitted from a laser writing unit (not shown) driven based on image information. When the electrostatic latent image formed on the surface of the photosensitive drum 11 by this irradiation moves to the developing position between the developing roller 23 and the photosensitive drum 11, toner adheres from the roller 23 and is developed into a toner image. The This toner image is transferred to the recording paper P and fixed by a fixing device (not shown). The transfer residual toner is removed from the surface of the photosensitive drum 11 by the cleaning blade 14 and the cleaning brush 15, and is conveyed and collected in a direction perpendicular to the paper surface by the waste toner collection coil 16.

  At this time, the developing unit 2 operates as follows. The developer cartridge 21 is mounted on the developer 22 in such a posture that its opening faces a developer receiving port (not shown) of the developer 22. When the sealing by the sealing material is released by some method, the developer stored in the inside is dropped into the developing device 22 through the opening and the developer receiving port. Due to this drop, the developer is supplied into the developing device 22. In the developing device 22, the non-magnetic pipe 23a is rotated by a drive means (not shown), and the developer sent from the developer cartridge 21 into the developing device 22 is attracted by the magnetic carrier generated by the magnetic roller 23b so that the magnetic carrier 23 It is carried on the surface of the magnetic pipe 23a. In this way, the nonmagnetic pipe 23a rotates while carrying the developer. The developing doctor 26 is disposed so as to face the nonmagnetic pipe 23a with a predetermined gap, and the developer carried on the surface of the nonmagnetic pipe 23a is in contact with the developing doctor 26 and the nonmagnetic pipe 23a. When passing through the gap with the surface, the thickness of the layer is regulated and frictional charging of the toner is promoted. When the nonmagnetic pipe 23a rotates and moves to the developing position, the toner adhered to the magnetic carrier is transferred to the electrostatic latent image on the photosensitive drum 11.

  Here, in the image forming apparatus according to this embodiment, based on the output voltage of the toner density sensor 27, whether or not the developing device 22 is set (attached) to the main body of the image forming apparatus is unsealed. It is determined whether or not stirring has been normally performed by the conveying screws 24 and 25. This will be described below.

FIG. 2 is a diagram showing an electrical connection relationship between the toner density sensor 27 and the host-side control board 30 in the image forming apparatus according to the present embodiment.
Connected to the control board 30 are n toner density sensors 27-1, 27-2,..., 27-n which are the number of developing units provided in the image forming apparatus (developing units are Y, M , C and K, n = 4). Two control lines, SCL (serial clock line) and SDA (serial data line), are commonly connected to the density sensors of all colors through an I ² C interface. The SCL and SDA are connected in the form of a daisy chain. Logically, up to 8 (n = 8) can be connected. In the I ² C interface, start activation is started from the control board 30 side at the timing determined by SCL and SDA at the beginning of communication. A request such as the type of read / write is transmitted to the SDA as a serial signal.

  Vcnt signal, which is a control voltage supplied to toner density sensors 27-1, 27-2,... 27-n, and detection voltages from toner density sensors 27-1, 27-2,. A certain Vt signal is independent and is provided for each developing unit. The Vcnt signals of the toner density sensors 27-1, 27-2,..., 27-n are connected to terminals (hereinafter referred to as PWM terminals) that can generate PWM signals in the ASIC or CPU mounted in the control board 30. ing. This PWM terminal can output all high (High) or all low (Low) signals in addition to the PWM signal. As will be described later, when accessing a memory chip (not shown) connected to the toner density sensors 27-1, 27-2,... 27-n, Vcnt is set to all high or all low, and the toner density sensor When reading the detection data of 27-1, 27-2, ... 27-n, the PWM signal is used. The memory chip access mode and the sensor mode for reading the toner density are exclusive operations. The detection voltage Vt from the toner density sensors 27-1, 27-2,... 27-n is pulled down by resistors 31-1, 31-2,. For this reason, when the toner density sensors 27-1, 27-2,... 27-n are not set, Vt = 0V when viewed from the CPU and ASIC of the control board 30, thereby the toner density sensor 27- In other words, 1, 27-2,..., 27-n can detect whether or not the developing device 22 is set in the image forming apparatus main body.

  FIG. 3 is a diagram showing an electrical connection relationship between the sensor unit 32 and the memory chip (EEPROM) 33 in the toner density sensor 27. The sensor unit 32 and the memory chip 33 are provided on the same substrate. Of the address terminals A0, A1, and A2 of the memory chip 33, A0 is connected to Vcnt, and A1 and A2 are connected to GND. This connection configuration is the same for a plurality of toner density sensors. That is, for example, the internal circuits of Y, M, C, and K toner density sensors are all the same and are common products.

Normally, in the I ² C interface, a hard address (physical address) is fixedly set on the memory chip side, and the soft address (logical address) of the memory chip to be selected is issued from the SDA line, and both addresses match. The memory chip is selected. Thereby, one device can be selected from the n devices physically connected to the line of the I ² C interface. However, in FIG. 2 and FIG. 3, since the hard addresses of n devices (memory chips) are the same, a specific device cannot be accessed as it is. Therefore, the addressing method has been devised as described below.

Set Vcnt to “1” only for devices that you want to select from the control board 30 side, and “0” for others. It means that you specify A0 = 1 in this way, given a "1,0,0" to the address "A0, A1, A2" of the physical device specified by SDA of I ² C interface, the Vcnt Only the device specified by = 1 returns an ACK, and the others return a NACK. Therefore, only the device set to Vcn = 1 can be read / written. Since only one memory chip can be selected at this time, the number of signal lines with Vcnt of “1” is one.

  As described above, in the present embodiment, the hard address on the memory chip side is connected to “A0, A1, A2” = “Vcnt, 0, 0”, and only Vcnt of the memory chip to be accessed is set to 1, and the other memory The Vcnt of the chip is 0. Conventionally, the hard address on the memory chip side is fixed, but in this embodiment, it has a hard address that changes as “0, 0, 0” or “1, 0, 0”. Further, since the soft address from the SDA is fixed to “1, 0, 0”, it is fixed to “1, 0, 0” when accessing any memory chip. In other words, the present embodiment is intended to change the idea that the hard address that has been fixed in the past is changed, and the soft address that has been changed is fixed.

  The greatest merit of this method is that the memory chip side does not need to have a fixed hard address from 0 to 3. For this reason, one type of toner density sensor can be used, and it is not necessary to separately make each color. As a result, sensor manufacturers and development unit production lines do not need to select a sensor for each color, thereby eliminating simple mistakes and careless mistakes. Therefore, troublesome management is unnecessary for the producer of the toner density sensor and the producer of the developing unit.

  Next, details of the sensor unit 32 and the memory chip 33 of the toner density sensor 27 will be described with reference to FIG. The sensor unit 32 includes an oscillation circuit 34, a resonance circuit 35, a phase comparison circuit 36, a smoothing circuit 37, and an amplifier circuit 38. Further, a memory chip 33 which is a nonvolatile memory is provided on the same substrate as the circuit substrate of the sensor unit 32.

  The oscillation circuit 34 has an oscillator OSC such as crystal or ceramics, an X-OR (exclusive OR) IC2-1, and a feedback resistor R1, and oscillates at 4 MHz. The resonance circuit 35 includes a first resonance circuit composed of a resistor R3 and a first coil L1, and a second resonance circuit having a second coil L2 coupled to the first coil L1 with a magnetic coupling coefficient k. . Further, a shared capacitor comprising three capacitors C1, C2, C3 shared by the first resonance circuit and the second resonance circuit is provided. As described above, the first resonance circuit and the second resonance circuit share the capacitor, so that the first resonance circuit and the second resonance circuit can have equivalent resonance characteristics. The second coil L2 is provided to face the first coil L1 and forms a resonance point.

  The output Vo1 from the oscillation circuit 34 is a rectangular wave as indicated by Vo1 in FIG. 5A, and is input to the first coil L1 via the resistor R3. The resistor R3 can limit the input impedance at the resonance point and prevent the oscillation circuit 34 from becoming unstable. In the second resonance circuit, a voltage Vo2 that cancels the voltage Vo1 input to the first coil L1 at the resonance point is output from the second coil L2. At this time, the mutual inductance between the first coil L1 and the second coil L2 changes due to the magnetic permeability of the developer in the vicinity of the first coil L1 and the second coil L2, and the output output from the second coil L2 The value Vo2 changes. The magnetic permeability of the developer varies depending on the mixing ratio between the magnetic particles and the toner, and is high when the toner concentration is low and low when the toner concentration is high. The voltage Vo2 output from the second coil L2 is a sine wave as shown in FIG. 5B. Here, the solid line is a waveform when the toner density of the developer is an appropriate value, and the broken line is a waveform when the toner density is lower than the appropriate value. As described above, the change in the toner density of the developer changes the mutual impedance at the resonance point, and a phase difference occurs in the waveform output from the second coil L2, as shown in Vo2 of FIG. 5A and FIG. 5B. .

  The voltage Vo2 output from the second coil L2 of the second resonance circuit is cut by the capacitor C4, and only the AC component is input to the X-ORIC2-2. The output of X-ORIC2-2 is fed back to its own input terminal by feedback resistor R200, and a DC bias voltage can be applied in the vicinity of the threshold voltage of the input terminal of X-ORIC2-2 (self-bias method). Therefore, it is a normal characteristic of a semiconductor that the threshold voltage largely fluctuates between lots. However, since the self-bias method can automatically follow this fluctuation, the operating point always comes in the vicinity of the threshold voltage. Therefore, it is sufficient that the operation input voltage of the X-ORIC2-2 is 100 mVp-p in amplitude.

  The X-ORIC 2-3 constituting the phase comparison circuit 36 compares the signal Vo1 from the oscillation circuit 34 with the signal Vo3 obtained by binarizing and inverting the sine wave from the resonance circuit 35 to obtain a binary signal Vo4. In other words, the X-ORIC2-3 detects the phase difference between the reference waveform Vo1 from the oscillation circuit 34 and the signal Vo3 that has undergone a phase change through the resonance circuit 35, and binary values of low / high in accordance with the phase difference. Output the signal Vo4. As shown in FIGS. 6A to 6C, when the toner density indicated by the broken line is lower than the output waveform output from the phase comparison circuit 36 when the toner density indicated by the solid line is appropriate, it is output from the phase comparison circuit 36. The high period of the output waveform is long.

  The binarized signal Vo4 is output from the phase comparison circuit 36 and input to a smoothing circuit 37 composed of a resistor R7, a capacitor C5, and an operational amplifier IC1-1. The smoothing circuit 37 integrates the rectangular wave of the binarized signal Vo4 with R7 and C5 to convert it into a DC voltage and inputs it to the operational amplifier IC1-1. Since the operational amplifier IC1-1 is composed of a voltage follower circuit, the input voltage Vo5 and the output voltage Vo6 of the operational amplifier IC1-1 have substantially the same value. Since the voltage follower circuit is a circuit that inputs with a high impedance and outputs with a low impedance, it is also called an impedance conversion circuit, and does not affect the integration circuit composed of the phase comparison circuit 36, the resistor R7, and the capacitor C5 in the previous stage. This is an important circuit having a function of smoothly delivering a voltage to the amplification circuit 38 in the stage. 7A, 7B and 7C show waveforms of Vo1, Vo4 and Vo6. Here, the solid line is the output voltage Vo6-1 when the toner density is appropriate, and the broken line is the output voltage Vo6-2 when the toner density is lower than the appropriate value.

  The DC voltage Vo6 from the smoothing circuit 37 is input to the DC amplifier circuit 38. The DC amplifier circuit 38 is composed of an operational amplifier IC1-2, resistors R8, R9, R10, R12, and a capacitor C9. The DC voltage Vo6 output from the smoothing circuit 37 changes only about 0.5 V even if the toner density difference is maximum, so if it is output as a sense signal to the upstream control board 30 as it is, it will be subject to disturbances such as external noise. N becomes worse and the accuracy becomes low. Therefore, the amplitude is amplified by the DC amplification circuit 38 and output to the control board 30 to improve the S / N. The DC amplification circuit 38 integrates and smoothes the Vcnt signal from the control board 30 with resistors R8 and R9 and a capacitor C9, converts it to a DC reference voltage Vref proportional to the duty of the PWM signal, and inputs it to the operational amplifier IC1-2. It has the function to do. Here, the charging / discharging time constant of the circuit constituted by the resistors R8 and R9 and the capacitor C9 is set to a value much longer than the period of the PWM signal so that the ripple of the PWM signal does not appear.

  The DC amplifier circuit 38 outputs the voltage Vo7 obtained by amplifying the difference between the reference voltage Vref and the output voltage Vo6 from the smoothing circuit 37 by-(R12 / R10) times to the connector terminal CN1 as the output voltage Vt. Capacitors C8 and C10 for eliminating the influence of external noise are connected to the connector terminal CN1. In this way, a sensor output Vt corresponding to the toner density is obtained. Thus, the Vcnt signal line is a selection line of the memory chip 33 and is also a reference voltage of the sensor unit 32, and is multiplexed.

  FIG. 8 is a graph showing an example of the relationship between the input control voltage Vcnt of the toner density sensor 27 and the output voltage Vt (hereinafter referred to as Vcnt-Vt characteristic). As shown in this figure, in the case of no developer, when Vcnt becomes about 4.3V or more, Vt increases almost linearly from 0V, and when Vcnt becomes 5V which is the same as the power supply voltage of the toner density sensor 27, Vt Becomes about 3V. When the amount of developer is small (L in the figure), when Vcnt becomes about 3.5V or more, Vt increases almost linearly from 0V, and when Vcnt becomes about 4.5V, Vt becomes about 5V. Become. Further, when the amount of the developer is medium (M in the figure), when Vcnt becomes about 3V or more, Vt increases almost linearly from 0V, and when Vcnt becomes about 4.2V, Vt becomes about 5V. Become. When the amount of developer is large (H in the figure), when Vcnt becomes about 2.8 V or more, Vt increases almost linearly from 0 V, and when Vcnt becomes about 4 V, Vt becomes about 5 V. .

  Next, based on the output voltage of the toner concentration sensor 27 having the above-described configuration, whether or not the developing device 22 is set in the image forming apparatus main body, whether or not the set developing device 22 is new, a sealant A procedure for detecting whether or not the sealing by the above has been released and whether or not the stirring has been normally performed by the conveying screws 24 and 25 will be described with reference to FIGS.

  Table 1 below shows an outline of each detection in the above procedure.

  As shown in (a) of this table, detection of whether or not it is set gives 5 V as Vcnt, and if Vt is 1 V or more, it is determined that it is set. Alternatively, 5 V is given as Vcnt, and if Vt is equal to or greater than the value stored in the first storage area of the memory chip 33, it is determined that it is set. Here, Vcnt is made to coincide with the power supply voltage of the concentration sensors 27-1 to 27-n to facilitate control.

  As shown in FIG. 8, when Vcnt = 5V is applied, Vt is about 3V in the absence of developer. Therefore, if the developing unit 22 is set, Vt becomes about 3V. Therefore, Vt is compared with the first fixed value (1V), and if it is more than that, it is determined that it is set. Here, the margin of about 2V is given because there is a variation inherent in the toner density sensor 27, and depending on the set, a voltage around 2V is probabilistically generated.

  When the value stored in the storage area is used as the first storage area of the memory chip 33, the developing unit 22 is set in the image forming apparatus main body in the inspection process during the manufacture of the image forming apparatus, and the reference device is set in the toner density sensor. Control of a specific value (here, 5 V) when a (testing jig in which magnetic particles equivalent to the initial agent and toner are mixed) is not connected, that is, when imitating a state without developer. The detection voltage of the toner concentration sensor 27 when the voltage Vcnt is applied is stored. In the case of the Vcont−Vt characteristic of FIG. 8, about 3V is stored in the first storage area of the memory chip 33. Since this value simulates the state of each toner density sensor 27 without the developer, it is a value reflecting a variation unique to the toner density sensor 27.

  Further, when the developing unit 22 is not set, the connection of the Vt input line in the control board 30 in the circuit diagram of FIG. 2 is lost, so the value of Vt is set to the ground level (pull-down resistors 31-1 to 31-n). 0V). Accordingly, the Vt value read by the CPU or ASIC of the control board 30 is 0 V, and it can be determined that the developing device 22 is not set based on this value.

  As shown in (a) of this table, detection of whether or not the set developing device 22 is a new one uses stored information in a new product detection mechanism or a new product detection area of the memory chip 33. As a new article detection mechanism, when a new device is used, a spring pin is sandwiched between gears that transmit rotational driving force to the conveying screws 24 and 25 and a predetermined circuit is electrically connected to the pin when the developer 22 is used. When the conveying screws 24, 25 are rotated, the gear is rotated once, the spring pin is removed, and the conduction is released. In addition, predetermined new data is written in the new mechanism detection area of the memory chip 33 when it is new, and it can be determined by reading from the CPU or ASIC of the control board 30. This new data is erased when it is first read.

  As shown in (c) of this table, the detection of whether or not there is developer in the developing device 22 (whether or not the sealing material has been pulled out) is given 4V as Vcnt, and Vt is less than 1.2V. If so, it is determined that there is no developer. Alternatively, 4V is given as Vcnt, and if Vt is less than the value stored in the second storage area of the memory chip 33, it is determined that there is no developer.

  When the developing device 22 is new, a sealant is stuck between the developer cartridge 21 and the stirring chamber of the developing device 22, and all of the initial agent is accommodated in the developer cartridge 21. When setting the developing device 22 in the main body of the image forming apparatus, it is necessary that the service person or the user pulls out the sealing material and moves the initial agent from the developer cartridge 21 to the lower stirring chamber. If the sealing material is pulled out and stirred, the unevenness of the initial material is made uniform, and the uniform developer is deposited on the detection part of the toner concentration sensor 27, and a predetermined voltage Vt appears. Therefore, if this operation is being performed, since the developer cartridge 21 exists in the developing device 22, it can be determined whether or not the sealing material has been pulled out based on the presence or absence of the developer.

  As shown in FIG. 8, when a developer is present and Vcnt is applied with 4 V, Vt is approximately 2.5 V when the developer is small and approximately 5 V when the developer is large. Therefore, Vt is compared with the second fixed value (1.2 V) in consideration of the inherent variation of the toner density sensor 27, and if it is more than that, it is determined that there is a developer.

  When the value stored in the storage area is used as the second storage area of the memory chip 33, the developing unit 22 is set in the image forming apparatus main body in the inspection process during manufacture of the image forming apparatus, and the reference device is set in the toner density sensor. Control of a specific value (4V in this case) when a (testing jig in which magnetic particles equivalent to the initial agent and toner are mixed) is not connected, that is, when imitating a state without developer. The detection voltage of the toner concentration sensor 27 when the voltage Vcnt is applied is stored. In the case of FIG. 8, the Vt value (for example, 0.003V) at Vt = 4V of the characteristic in which the characteristic without developer is translated in the direction of the small amount of developer (the movement amount is obtained by experiment) is stored. This value is a value reflecting the variation inherent in the toner density sensor 27 because it mimics the state of each toner density sensor 27 without developer.

  As shown in (d) of this table, detection of whether or not the developer has been normally stirred gives a predetermined value (for example, 4V) as Vcnt, and Vt is equal to or greater than the third fixed value (1.3V). If it is, it is determined that the developer has been normally stirred. Alternatively, a predetermined value (eg, about 3.6 V) is given as Vcnt, and if Vt is equal to or greater than the value stored in the third storage area of the memory chip 33, it is determined that the developer has been normally stirred.

  As shown in FIG. 8, when the developer is properly stirred (drug amount / large, agent amount / medium, agent amount / small), 3 to 4 V should be output without fail. When the voltage is less than 1.3 V, the voltage Vt when the developer is determined to be present has not increased by 0.1 V from 1.2 V, so the conveyance screw or the drive source is abnormal or the toner density sensor is defective. However, in any case, a problem has occurred somewhere, so it is determined that the stirring is poor. If it is 1.3 V or more, it is judged as normal stirring.

  When the value stored in the storage area is used as the third storage area of the memory chip 33, the developing device 22 is set in the image forming apparatus main body in the inspection process at the time of manufacturing the image forming apparatus, and the reference device is set in the toner density sensor. When a (testing jig in which magnetic particles equivalent to the initial agent and toner are mixed) is connected, that is, when imitating a state where the agent is normally stirred (in this case, about 3. The voltage detected by the toner density sensor 27 when the control voltage Vcnt of 6V) is applied is stored.

  As shown in FIG. 8, when the developer is normally stirred (many, medium, and small), the change width of Vt is 5V. Therefore, about 3.6 V is set as Vcnt corresponding to the central value of about 2.5 V in the amount / medium, and a value of about 2.5 V is stored in the third storage area of the memory chip 33. If the detected voltage of the toner density sensor 27 when the control voltage Vcnt of about 3.6 V) is applied is about 2.5 V or more, it is determined that the developer is normally stirred, and is less than about 2.5 V. If so, it is determined that the stirring is poor.

The operation when detection is performed based on (A) to (D) described above will be described.
FIG. 9 is a timing chart showing an operation when it is detected whether or not the developing device 22 is set in the image forming apparatus using Vt1 = 1V in (a) of Table 1. As shown in this figure, SCL and SDA are inactive, and the control voltage Vcnt is applied to any one of the density sensors 27-1 to 27-n corresponding to the color to be detected as to whether or not the developing device 22 is set. Is supplied at a specific value (first control voltage, for example, 5V) with all high, and whether or not Vt is set is detected depending on whether or not Vt becomes 1V or more. At this time, since SCL and SDA are made inactive, communication is not performed between the memory chip 33 of each color and the control board 30, and no matter how the control voltage Vcnt is applied, the memory chip 33 is written. / Reading and malfunctioning are not performed.

  FIG. 10 is a timing chart showing an operation when it is detected whether or not the developing device 22 is set in the image forming apparatus using the stored value of the first storage area in (a) of Table 1. As shown in this figure, first, a clock is supplied from the SCL to the memory chip of the toner density sensor 27 (here, the toner density sensor 27-1) of the developing unit 2 corresponding to the color to be detected, and the memory chip from the SDA. The address “001” is supplied, the data in the first storage area is read, and the value is temporarily stored in the storage unit on the control board 30 side.

  Next, a control voltage Vcnt having a specific value (for example, 5 V) is supplied to the toner density sensor 27-1, and the returned Vt value is compared with the value previously stored in the first storage area. If the Vt value is greater than or equal to the value stored in the first storage area, it is determined that the developing device 22 is set, and if the returned Vt value is less than the value in the first storage area, the developing device 22 It is determined that it is not set.

  According to this method, the data in the first storage area is detection data when it is actually set during the manufacturing process, and therefore, regardless of variations in a large number of density sensors as in the method shown in FIG. Since it can be detected with a value corresponding to the sensor, there is no risk of false detection. First, SCL, SDA, and Vcnt = H are sent to access the memory chip, and the memory chip is accessed. By setting the Vcnt value at the time of sensor access to 5 V, the memory access is not possible. However, since the detection voltage of the set detection is returned to Vt, the memory access and the sensor access have been described as being exclusive. However, simultaneous processing is performed only under the condition of Vcnt = 5V, thereby improving the time efficiency. It is possible. However, after reading the stored data in the access mode, it is easier to create the software by switching to the sensor mode and reading Vt to determine whether or not it is set.

  FIG. 11 is a timing chart showing an operation when it is determined whether or not the sealing material has been pulled out using Vt2 = 1.2 V in Table 1 (c). Deactivate SCL and SDA. Also, Vcnt = 4V (second control voltage: PWM signal duty = 80%) is sent from the control board 30 and converted to a 4V DC reference voltage Vref proportional to the duty of the PWM signal by the circuit on the density sensor 27 side. Then, it is detected from the level of the voltage Vt whether the developer is present in the developing unit 22 or not. Here, if Vt is 1.2V or more, it is determined that there is a developer, and if it is less than 1.2V, it is determined that there is no developer.

  FIG. 12 is a timing chart showing an operation when it is determined whether or not the sealing material has been pulled out using the storage data in the second storage area in Table 1 (c). In this figure, the access to the memory chip 33 is before the broken line timing T0, and the sensor access to the toner density sensor 27-1 is shown after T0.

  As in the case of FIG. 9, the access operation to the memory chip 33 reads the data in the second storage area of the memory chip 33 and temporarily stores the value in the storage unit on the control board 30 side. Next, Vcnt = 4V is supplied to the toner density sensor 27-1, the returned Vt value is compared with the value previously stored in the second storage area, and the returned Vt value is stored in the second storage area. If the value stored in the area is equal to or greater than the value stored in the area, it is determined that the sealing material has been pulled out. If the returned Vt value is less than the value stored in the second storage area, it is determined that the sealing material has not been pulled out.

  FIG. 13 is a timing chart showing an operation when it is determined whether or not normal stirring is performed by the conveying screws 24 and 25 using Vt3 = 1.3 V in Table 1 (d). As shown in this figure, SCL and SDA are deactivated. Also, Vcnt = 4V (third control voltage, PWM signal duty = 80%) is sent from the control board 30 and converted to a DC reference voltage Vref of 4V proportional to the duty of the PWM signal by the circuit on the density sensor 27 side. Whether the developer in the developing device 22 is sufficiently stirred is determined from the level of the voltage Vt. Here, if Vt is 1.3 V or more, it is determined that the stirring is normally performed, and if it is less than 1.3 V, it is determined that the stirring is abnormal.

  Here, when the sealing material is pulled out according to the procedure, the initial agent is transferred to the stirring chamber, and the stirring operation is performed. However, when the conveying screws 24 and 25 do not rotate normally, or when the initial agent itself is exposed to high temperature and solidifies, Vt does not become a normal value (1.3 V or more). That is, it indicates that an appropriate stirring operation is not performed. On the other hand, when the initial agent is normally charged and normally stirred, an appropriate Vt value can be obtained from the toner concentration sensor 27-1.

  FIG. 14 is a timing chart showing an operation when it is determined whether or not normal agitation has been performed by the conveying screws 24 and 25 using the data stored in the third storage area in (d) of Table 1. In this figure, the access to the memory chip 33 is shown before the broken line timing T1, and the sensor access to the toner density sensor 27-1 is shown after T1.

  As in the case of FIG. 10, the access operation to the memory chip 33 reads the data in the third storage area of the memory chip 33 and temporarily stores the value in the storage unit on the control board 30 side. Next, as in the case of FIG. 12, Vcnt is supplied to the toner density sensor 27-1, the returned Vt value is compared with the value previously stored in the third storage area, and the returned Vt is returned. If the value of is greater than or equal to the value stored in the value in the third storage area, it is determined that the agitation is normal. If the returned Vt value is less than the value stored in the third storage area, the agitation is abnormal. It is determined that there is.

Next, processing executed during the initial operation when the image forming apparatus is turned on will be described with reference to the flowchart shown in FIG.
When the power of the image forming apparatus is turned on or when the exterior cover is closed, the entire image forming apparatus is warmed up, and various checks are performed to start up (step S1). Then, it is checked whether the developing unit 2 is normally set at a predetermined timing (step S2). This may happen when the service person or user pulls out the used development unit and replaces it with a new development unit while the power is off or the cover is open. This is because they sometimes forget to set.

  As the detection method in step S2, the method described with reference to (a) of Table 1 is used. If the developing unit 2 is not set normally, the process proceeds to step S3 to stop the machine and display an error. If the developing unit 2 is normally set, the process proceeds to step S4, and a new article detection process is performed. The new article detection process uses the method described with reference to (a) of Table 1. In the case of a new product, the process proceeds to step S5, and a stirring operation is performed for a predetermined time. This stirring operation is the first stirring operation after the power is turned on or the machine cover is closed, and is a preparatory stirring operation for detecting the absence of the agent performed in the next step S6.

  In step S6, it is determined whether or not the developer has moved into the developing device 22 (whether or not the seal material has been pulled out) using any of the methods described with reference to (c) of Table 1. . If it is determined that the user has forgotten to pull out the seal, the process proceeds to step S8 to stop the machine and display an error. When it determines with having pulled out, it transfers to step S7 and performs stirring operation. Here, the sum of the stirring time in step S5 and the stirring time in step S7 is, for example, about 100 seconds. In this stirring operation, most of the toner is in an uncharged state, so that charging can be performed by sufficiently stirring the initial agent that cannot be moved to the photoreceptor in terms of potential. Even when it is determined in step S4 that the developing device is already in use, the stirring operation is executed in step S7.

  After completion of the stirring time, the process proceeds to step S9, and it is checked whether or not the stirring is normally performed using the method described with reference to (d) of Table 1. If it is determined that the agitation is not normal, the machine is stopped and an error is displayed. When it is determined that the agitation is normal, the process proceeds to step S10, where the normal flow is merged again. Here, instead of 1.3 V as the third fixed value, the determination method of the Vt value obtained in step S6 plus any V may be used.

  The manufacturing lot number and the like are stored in the memory chip 33, and when the contents of the memory chip 33 are read, this information is also read out, and the developing unit attached to the image forming apparatus is determined from the manufacturing lot number. You may comprise so that it may be judged whether it is a regular article. If it is not a regular product, the user may be prompted to replace the developing unit by prohibiting image formation or changing the image formation conditions so as to form a deteriorated image. Further, when the developing unit 2 breaks down, the manufacturing history can be traced back from the manufacturing lot number, and the cause analysis of the occurrence of the failure can be easily performed.

  Further, when reading the contents of the memory chip 33, the life and deterioration state of the developing unit 2 are grasped from the usage history of the parts stored in the memory chip 33 and the usage history of the developing unit 2 itself. May be. For the purpose of grasping the life, for example, the memory chip 33 stores the parts and the usage history of the developing unit 2 as well as the parts of the developing unit 2, the warranty period of the developing unit 2, the limit copy number, and the like. This is realized by reading out lifetime information such as the warranty period and the limit number of copies as well as the usage history of the above. Then, the CPU in the image forming apparatus compares the use history with the life information, and if the use history exceeds the life information, a warning may be displayed as the life of the developing unit 2 is reached. Such a life detection of the developing unit 2 is not limited to the initial operation when the power is turned on, and can be performed at a predetermined timing, for example, when a predetermined number of copies are executed.

  In addition to the photosensitive member 11 and the developing roller 23 in the developing unit 2, the components include devices such as the developing unit 2 and a charging device. Further, the deterioration state of the developing unit may be grasped from the read usage history information, and the developing condition or the like may be changed according to the deterioration state. Further, when reading the contents of the memory chip 33, the sensitivity (toner density / output voltage) and detection level (control voltage / output voltage) specific to the toner density sensor 27 are read, and this information is stored in the memory of the image forming apparatus. May be stored. This sensitivity information is used at the time of toner density control, and the detection level information is read from the image forming apparatus in the above-described replacement initial operation mode.

  As described above, after communicating with the memory chip of the developing unit mounted at the Y position, and detecting the new article detection, the erroneous set detection, and the writing of the use history to the memory chip, the mounting is performed at the M position. For the development unit, new article detection, erroneous set detection, and memory chip information update control are performed. This control flow is the same as the control flow performed for the developing unit mounted at the Y position. The same communication control is performed for the developing unit mounted at the C position and the K position to detect a new product. , Wrong set detection, update of memory chip information.

  In the above-described embodiment, a new product is detected for a developing unit mounted at a certain color position, a new product is detected for a developing unit mounted at a different color position after detecting a new set, an erroneous set detection, and a memory chip information update. Incorrect set detection and memory chip information update. However, the present invention is not limited to this. For example, after a new product is detected for the developing unit mounted at the Y position, a new product is detected for each of the developing units mounted at the M, C, and K positions. When the new detection of each developing unit installed in the position is completed, the erroneous setting detection of each developing unit installed in each color position is performed, and then each developing unit installed in each color position is detected. The memory chip information may be updated.

  In this embodiment, the example in which the memory chip is provided on the same substrate as the toner concentration sensor has been described. However, the present invention is not limited to this. For example, the memory chip may be provided on the same substrate as the P sensor.

FIG. 2 is a diagram illustrating a configuration of a photoreceptor unit and a development unit in an image forming apparatus according to an embodiment of the present invention. FIG. 4 is a diagram illustrating an electrical connection relationship between a toner density sensor and a host-side control baud in the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a diagram illustrating an electrical connection relationship between a sensor unit and a memory chip in a toner concentration sensor. It is a figure which shows the circuit structure of the sensor part of a toner density sensor. It is a figure which shows the relationship between the output voltage of the oscillation circuit of the sensor part of a toner density sensor, and the resonance circuit, and a toner density. It is a figure which shows the relationship between the output voltage of a phase comparison circuit of a sensor part of a toner density sensor, and toner density. It is a figure which shows the relationship between the output voltage of the smoothing circuit of the sensor part of a toner density sensor, and toner density. 6 is a graph showing a relationship between an input control voltage Vcnt and a sensor output voltage Vt in a toner density sensor. FIG. 6 is a timing chart showing an operation when detecting whether or not the developing device is set in the image forming apparatus using Vt1 = 1V in (a) of Table 1. FIG. 6 is a timing chart showing an operation when it is detected whether or not the developing device is set in the image forming apparatus using the stored value of the first storage area in (a) of Table 1. It is a timing diagram which shows operation | movement when determining whether the sealing material was pulled out using Vt2 = 1.2V in (c) of Table 1. FIG. It is a timing diagram which shows operation | movement when determining whether the sealing material was pulled out using the memory | storage data of the 2nd memory | storage area in (1) of Table 1. FIG. It is a timing diagram which shows operation | movement when determining whether normal stirring was performed using Vt3 = 1.3V in (d) of Table 1. FIG. It is a timing diagram which shows the operation | movement when determining whether normal stirring was performed using the memory | storage data of the 3rd memory area in (d) of Table 1. FIG. 6 is a flowchart illustrating processing executed during an initial operation when the image forming apparatus is powered on.

Explanation of symbols

  2 ... developing unit, 21 ... developer cartridge, 22 ... developer, 24,25 ... conveying screw, 27 ... density sensor, 30 ... control board, 32 ... sensor Part, 33 ... Memory chip.

Claims (18)

A developer cartridge containing a developer in which magnetic particles and toner are mixed at a predetermined ratio;
A developing device in which the developer cartridge is detachably mounted and has a function of stirring the developer supplied from the developer cartridge, and is detachably mounted in the image forming apparatus main body;
A toner concentration provided in the developing device and detecting the toner concentration in the developing device and outputting toner concentration data as a sensor output voltage value to the control device in response to a control voltage supplied from the control device. A sensor,
Determined from a sensor output voltage value when a predetermined first control voltage is applied from the control device to the toner concentration sensor, and a control voltage vs. sensor output voltage characteristic of the toner concentration sensor when the developer cartridge is not attached. And determining means for determining whether or not the developing device is attached to the image forming apparatus main body based on a magnitude relationship with a first sensor output voltage corresponding to the first control voltage. Image forming apparatus. The image forming apparatus according to claim 1.
The toner density sensor has storage means for storing the first sensor output voltage, and the determination means has a sensor output voltage when a predetermined first control voltage is applied to the toner density sensor, and the storage means. An image forming apparatus that compares the first sensor output voltage stored in the image sensor. The image forming apparatus according to claim 2.
The first sensor output voltage stored in the storage means is obtained without attaching an inspection jig in which magnetic particles equivalent to the initial agent and toner are mixed to the toner concentration sensor when the toner concentration sensor is manufactured. An image forming apparatus comprising: a sensor output voltage of a toner density sensor when the first control voltage is applied to the toner density sensor. The image forming apparatus according to claim 1.
Means for executing a stirring operation of the magnetic particles and the toner for a predetermined time when it is determined that the developing device is attached to the image forming apparatus main body;
From the sensor output voltage value when a predetermined second control voltage is applied from the control device to the toner concentration sensor after the stirring, and the control voltage vs. sensor output voltage characteristic of the toner concentration sensor when the developer cartridge is not mounted. And means for determining whether or not the seal material of the developer cartridge has been pulled out based on the determined magnitude relationship with the second sensor output voltage corresponding to the second control voltage. Image forming apparatus. The image forming apparatus according to claim 4.
The toner density sensor has storage means for storing the second sensor output voltage, and the determination means has a sensor output voltage when a predetermined second control voltage is applied to the toner density sensor, and the storage means. And an output voltage of the second sensor stored in the image forming apparatus. The image forming apparatus according to claim 5.
The second sensor output voltage stored in the storage means is obtained without attaching a test jig in which magnetic particles equivalent to the initial agent and toner are mixed to the toner concentration sensor when the toner concentration sensor is manufactured. An image forming apparatus comprising: a sensor output voltage of a toner density sensor when the second control voltage is applied to the toner density sensor. The image forming apparatus according to claim 1.
Means for executing a stirring operation of the magnetic particles and the toner for a predetermined time when it is determined that the developing device is attached to the image forming apparatus main body;
Determined from a sensor output voltage value when a predetermined third control voltage is applied from the control device to the toner density sensor after the stirring, and a control voltage vs. sensor output voltage characteristic of the toner density sensor when the developer cartridge is mounted. And a means for determining whether or not the developer has been normally stirred based on a magnitude relationship with a third sensor output voltage corresponding to the third control voltage. . The image forming apparatus according to claim 7.
The toner density sensor has storage means for storing the third sensor output voltage, and the determination means has a sensor output voltage when a predetermined third control voltage is applied to the toner density sensor, and the storage means. And an output voltage of the third sensor stored in the image forming apparatus. The image forming apparatus according to claim 8.
The third sensor output voltage stored in the storage means is obtained by attaching an inspection jig in which magnetic particles equivalent to the initial agent and toner are mixed to the toner concentration sensor when the toner concentration sensor is manufactured. An image forming apparatus comprising a sensor output voltage of a toner density sensor when a third control voltage is applied to the toner density sensor. The image forming apparatus according to any one of claims 4 to 6,
Means for detecting whether the developing device is new;
An image forming apparatus comprising: a control unit that operates a unit that executes the stirring operation for a predetermined time when it is detected that the unit is new. The image forming apparatus according to claim 2, 5 or 8.
The control voltage is a PWM signal in which high and low are switched at a predetermined interval, and the PWM operation is not performed during access to the storage means, and a signal having only one value of high or low is used. Image forming apparatus. The image forming apparatus according to claim 2, 5 or 8.
The image forming apparatus is characterized in that the storage means is not accessed during the toner concentration detection operation by the control voltage. The image forming apparatus according to claim 2, 5 or 8.
There are as many toner concentration sensors as the number of developing units, the data storage means is a nonvolatile memory having an I ² C interface, and a serial clock line and serial data lines to the nonvolatile memory are stored in a plurality of nonvolatile memories. Also connected in a daisy chain format, one of the terminals supplied with a 3-bit address for selecting the nonvolatile memory is connected to the output terminal of the control voltage, and the other is connected to GND or Vcc. An image forming apparatus. The image forming apparatus according to claim 13.
The plurality of toner density sensors have the same connection form of terminals to which a 3-bit address for selecting the nonvolatile memory is supplied, and the plurality of toner density sensors all have a common configuration. Forming equipment. The image forming apparatus according to claim 2, 5 or 8.
The image forming apparatus, wherein the data storage unit stores manufacturing information relating to a toner density sensor. The image forming apparatus according to claim 2, 5 or 8.
6. The image forming apparatus according to claim 1, wherein manufacturing information of the image forming apparatus formed by combining the developing unit and the toner density sensor is stored in the data storage unit. The image forming apparatus according to claim 2, 5 or 8.
The image forming apparatus, wherein the data storage means stores a use history of the image forming apparatus. The image forming apparatus according to claim 2, 5 or 8.
The image forming apparatus, wherein the data storage means stores a use history of a component mounted on the image forming apparatus.

Images