JP2015014687A - Oscillation circuit detector and method for attaching oscillation circuit detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an oscillation circuit detector for detecting, on the basis of the frequency of a signal outputted from an LC oscillation circuit including a pattern coil and a pattern resistor formed on a substrate by a planar pattern and connected in series, the magnetic permeability or temperature of a prescribed space facing the formation surface of the pattern coil, the oscillation circuit detector having improved detection accuracy.SOLUTION: An oscillation circuit detector, including a coil formed on a substrate by a planar pattern and a pattern resistor connected in series to the coil and formed by a zigzag-shaped planar pattern on the same surface of the substrate as the formation surface of the coil, is attached in a state in which the formation surface of the coil faces a prescribed space so that an angle among sharp angles formed by a straight line passing through the center of the coil and the center of the pattern resistor and a straight line passing through the center of the coil or pattern resistor and a heat source being the source of heat generation is within a prescribed angle.

Description

  The present invention relates to an oscillating circuit detector and a method for attaching an oscillating circuit detector, and more particularly, to an attaching mode of the oscillating circuit detector.

  In recent years, there has been a tendency to digitize information, and image processing apparatuses such as printers and facsimiles used for outputting digitized information and scanners used for digitizing documents have become indispensable devices. Such an image processing apparatus is configured as an MFP (Multi Function Peripheral) that can be used as a printer, a facsimile, a scanner, and a copier by providing an imaging function, an image forming function, a communication function, and the like. Many.

  Among such image processing apparatuses, an image is formed by attaching a developer such as toner to the transfer paper, and the formed toner is fixed to the transfer paper by heating and pressurizing the formed transfer paper. There is known an electrophotographic image forming apparatus that forms an image by causing the image to be formed. Among such electrophotographic image forming apparatuses, there are those that use a two-component developer in which a carrier that is magnetic particles and a non-magnetic toner are mixed.

  In such an image forming apparatus using a two-component developer, only the toner is consumed by the image formation, but in order to form a stable quality image, the toner concentration in the developer in the developer is set. It is necessary to keep the proper range. Therefore, in an image forming apparatus using such a two-component developer, it is necessary to measure the toner concentration in the developer in the developer.

  Therefore, an image forming apparatus using such a two-component developer is usually provided with a toner concentration detector for measuring the concentration of toner in the developer in the developer. As this toner density detector, one using an LC oscillation circuit including a pattern coil formed in a planar pattern on a substrate has been proposed and already known (for example, see Patent Document 1).

  A toner concentration detector using an LC oscillation circuit including such a pattern coil has a magnetic permeability in a developing device facing the plane on which the pattern coil is formed based on the frequency of a signal output from the LC oscillation circuit. By detecting, the density of the toner in the developer in the developing device is detected.

  That is, the toner density detector using the LC oscillation circuit including such a pattern coil has a magnetic permeability that is generated when only the toner is consumed by image formation and the density of the toner in the developer in the developer changes. The change is detected through an inductance change of the pattern coil.

  However, the frequency of a signal output from such an LC oscillation circuit is generally responsive to ambient temperature. Therefore, in the toner concentration detector using such an LC oscillation circuit, an error occurs in the detected concentration due to a change in the environmental temperature. This is because a physical quantity such as a resistance value or electric capacity of each element constituting the LC oscillation circuit changes according to the environmental temperature, and as a result, the oscillation frequency changes.

  Therefore, the above problem can be avoided by using an LC oscillation circuit in the toner density detector that can reduce the influence on the oscillation frequency even if the physical quantity of each element constituting the circuit changes according to the environmental temperature. be able to. As such an LC oscillation circuit, an LC oscillation circuit in which a pattern resistor formed by a planar pattern on the same plane as the pattern coil is connected in series to the pattern coil is conceivable.

  By simply connecting the pattern coil and pattern resistor in series and adjusting the resistance value of the pattern resistor, an LC oscillator circuit that reduces the effects of temperature changes in the physical quantities of the elements that make up the circuit can be easily designed. It becomes possible to do. The toner density detector using such an LC oscillation circuit is arranged and fixed so that the surface on which the pattern coil is formed is opposed to the developing device, so that the development can be performed stably without depending on the environmental temperature. It is possible to detect the toner concentration in the developer in the container.

  By the way, in an electrophotographic image forming apparatus, a conveying screw for conveying a developer filled inside is usually provided in the developing device, and the inside is filled by rotating the conveying screw. The developer is spread over the entire developing device. For this reason, in such an electrophotographic image forming apparatus, heat is generated by friction between the shaft of the conveying screw and the bearing thereof, and a temperature gradient is generated in the housing constituting the developing device using that portion as a heat source. When a temperature gradient is generated in the casing constituting the developing device, a temperature gradient is also generated in the toner concentration detector attached to the casing portion.

  However, since the toner density detector using the LC oscillation circuit including the pattern coil and the pattern resistor is used on the assumption that there is no temperature difference between the two, the toner density detector is used as described above. When a temperature gradient occurs, there is a problem that an error occurs in the detected density.

  Such a problem is not limited to a toner concentration detector that is attached to a developer containing a developer and detects the concentration of toner in the developer in the developer, but has a temperature gradient as described above. A magnetic permeability detector that detects the magnetic permeability of a predetermined space facing the plane on which the pattern coil is formed by using an LC oscillation circuit including a pattern coil and a pattern resistor in the generated usage environment can be similarly generated. It is a problem.

  Also, in such a permeability detector using an LC oscillation circuit, assuming that the permeability in a range that affects the inductance of the pattern coil is constant, the oscillation frequency variation of the LC oscillation circuit varies with temperature. It becomes only an ingredient. Therefore, the magnetic permeability detector using such an LC oscillation circuit not only detects the magnetic permeability, but can also be used as a temperature sensor when the magnetic permeability is constant. Even when a magnetic permeability detector using such an LC oscillation circuit is used as a temperature sensor, if there is a temperature difference between the pattern coil and the pattern resistance, an error occurs in the detected temperature. There is.

  The present invention has been made in view of the above circumstances, and is based on the frequency of a signal output from an LC oscillation circuit including a pattern coil and a pattern resistor formed in a planar pattern on a substrate and connected in series. An object of the present invention is to improve the detection accuracy of an oscillation circuit detector that detects the magnetic permeability or temperature of a predetermined space facing the formation surface of the pattern coil.

  In order to solve the above problem, an oscillation circuit detector for detecting a physical quantity in a predetermined space based on a frequency of a signal output from an oscillation circuit, which is formed by a planar pattern on a substrate and has a physical quantity in the predetermined space. A coil whose inductance changes due to the change, a capacitor provided on the surface of the substrate opposite to the surface on which the coil is formed, and a capacitor connected to form a resonance current loop with the coil and a part of the resonance current loop An electrical component including an output terminal that outputs a signal corresponding to the potential of the first electrode, and a series of fold-like planar patterns connected in series to the resonance current loop and on the same plane as the coil formed on the substrate. A straight line passing through the center of the coil and the center of the pattern resistance, and the coil or the center of the pattern resistance. The coil forming surface is mounted in a state facing the predetermined space so that an acute angle among angles formed with a straight line passing through a heat source that is a generation source of the coil is within a predetermined angle. To do.

  According to another aspect of the present invention, there is provided an oscillation circuit detector mounting method for detecting a physical quantity in a predetermined space based on a frequency of a signal output from an oscillation circuit. A coil whose inductance changes due to a change in a physical quantity in a predetermined space, a capacitor provided on a surface of the substrate opposite to the surface on which the coil is formed, and a capacitor connected to form a resonance current loop with the coil and the resonance An electrical component including an output terminal for outputting a signal corresponding to a potential of a part of the current loop, and a series of the resonance current loop connected to the resonance current loop in a folded manner on the same plane as the coil formed on the substrate. A straight line passing through the center of the coil and the center of the pattern resistor, and the coil or the pattern. Mounting with the coil forming surface facing the predetermined space so that the acute angle of the angle formed by the straight line passing through the center of resistance and the heat source that is the heat generation source is within the predetermined angle. It is characterized by being able to.

  According to the present invention, on the basis of the frequency of the signal output from the LC oscillation circuit including the pattern coil formed in a planar pattern on the substrate and connected in series and the pattern resistor, the pattern coil is opposed to the formation surface. In the oscillation circuit detector that detects the magnetic permeability or temperature of the predetermined space, it is possible to improve the detection accuracy.

It is a figure which shows the circuit structure of the magnetic permeability sensor which concerns on embodiment of this invention. It is a perspective view showing an outline of a magnetic permeability sensor concerning an embodiment of the present invention. It is a 6-face figure which shows the magnetic permeability sensor which concerns on embodiment of this invention. It is a figure which shows the function structure of the apparatus containing the magnetic permeability sensor which concerns on embodiment of this invention. It is a figure which shows the structure of the interface which processes the output signal of the magnetic permeability sensor which concerns on embodiment of this invention. 1 is a diagram illustrating a mechanical configuration of an image forming apparatus including a developing device on which a magnetic permeability sensor according to an embodiment of the present invention is mounted. It is a perspective view which shows the developing device by which the magnetic permeability sensor which concerns on embodiment of this invention is mounted. FIG. 3 is a perspective view showing the inside of the developing device according to the embodiment of the present invention. It is a figure which shows the side cross section of the developing device which concerns on embodiment of this invention. FIG. 2 is a front view illustrating an overview of a developing device according to an embodiment of the present invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor which concerns on embodiment of this invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor which concerns on embodiment of this invention. FIG. 4 is a diagram illustrating an example of a manner in which a magnetic permeability sensor according to an embodiment of the present invention is attached to a developing device, and a state of a temperature distribution in a main scanning direction in the developing device according to the embodiment of the present invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor in embodiment of this invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor in embodiment of this invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor in embodiment of this invention. It is a figure which shows the count aspect of the output signal of the magnetic permeability sensor which concerns on embodiment of this invention. It is a figure which shows the count aspect of the output signal of the magnetic permeability sensor which concerns on embodiment of this invention. It is a figure which shows the temperature characteristic of the oscillation frequency by the crystal oscillation circuit which concerns on embodiment of this invention. It is a figure which shows the temperature characteristic of the inductance of the coil which concerns on embodiment of this invention. It is a figure which shows the temperature characteristic of the capacity | capacitance of the capacitor | condenser which concerns on embodiment of this invention. It is a figure which shows the temperature characteristic of the resistance which concerns on embodiment of this invention. It is a figure which shows the graph of the inductance component of the pattern resistance which concerns on embodiment of this invention. It is a figure explaining an inductance component when the surrounding magnetic permeability changes in pattern resistance concerning an embodiment of the present invention. It is a figure which shows the difference of the temperature characteristic of the oscillation frequency by the some resistance value in the magnetic permeability sensor which concerns on embodiment of this invention. It is a figure which shows the formation aspect of the pattern resistance contained in the magnetic permeability sensor which concerns on embodiment of this invention. It is a figure which shows the example of the pattern resistance which concerns on other embodiment of this invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor in embodiment of this invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor in embodiment of this invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor in embodiment of this invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor in embodiment of this invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor in embodiment of this invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor in embodiment of this invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor in other embodiment of this invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor in other embodiment of this invention. It is a figure which shows an example of the attachment aspect to the developing device of the magnetic permeability sensor in other embodiment of this invention.

Embodiment 1 FIG.
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, the magnetic permeability is an oscillation circuit detector using an LC oscillation circuit including a pattern coil formed in a planar pattern on a substrate and a pattern resistor formed in a folded pattern in the planar pattern on the substrate. A method for improving the detection accuracy of the sensor will be described. In this embodiment, the toner is attached to a developing device in an electrophotographic image forming apparatus using a two-component developer in which a carrier that is magnetic particles and a toner that is a nonmagnetic developer are mixed. As an example, the magnetic permeability sensor is used as a toner concentration detector for measuring the concentration of toner in the developer inside the developing device.

  First, the circuit configuration of the magnetic permeability sensor 100 according to the present embodiment will be described with reference to FIG. FIG. 1 is a block diagram schematically showing a circuit configuration of the magnetic permeability sensor according to the present embodiment. As shown in FIG. 1, the magnetic permeability sensor 100 according to the present embodiment is an oscillation circuit based on a Colpitts-type LC oscillation circuit, and includes a pattern coil 101, a pattern resistor 102, a first capacitor 103, and a second capacitor 104. , Feedback resistor 105, unbuffered ICs 106 and 107, and output terminal 108.

  The pattern coil 101 is a coil on a plane constituted by signal lines patterned on the plane on the substrate constituting the magnetic permeability sensor 100. As shown in FIG. 1, the pattern coil 101 has an inductance L obtained by the coil. In the pattern coil 101, the value of the inductance L varies depending on the magnetic permeability of the space opposed to the plane on which the coil is formed. As a result, the magnetic permeability sensor 100 according to the present embodiment oscillates a signal having a frequency corresponding to the magnetic permeability of the space where the coil surfaces of the pattern coil 101 face each other.

The pattern resistor 102 is a resistor configured by a pattern of signal lines formed on the substrate in the same manner as the pattern coil 101. The pattern resistor 102 according to the present embodiment is a pattern formed in a zigzag shape, and thereby creates a state in which current does not flow more easily than a linear pattern. As shown in FIG. 1, the pattern resistor 102 has a resistance value _{R P.} As shown in FIG. 1, the pattern coil 101 and the pattern resistor 102 are connected in series. Thus, by connecting the pattern resistor 102 in series with the pattern coil 101, the magnetic permeability sensor 100 according to the present embodiment has its own oscillation frequency temperature characteristic oscillated by the crystal oscillation circuit 70, as will be described later. It is possible to cancel the calculation error of the oscillation frequency by being similar to the temperature characteristic of the frequency, and to stably detect the magnetic permeability of the space that opposes the plane on which the pattern coil 101 is formed without depending on the temperature. Become.

  The first capacitor 103 and the second capacitor 104 are capacitors that together with the pattern coil 101 constitute a Colpitts LC oscillation circuit. Therefore, the first capacitor 103 and the second capacitor 104 are connected in series with the pattern coil 101 and the pattern resistor 102. A resonance current loop is constituted by a loop constituted by the pattern coil 101, the pattern resistor 102, the first capacitor 103, and the second capacitor 104.

The feedback resistor 105 is inserted to stabilize the bias voltage. Due to the functions of the unbuffered IC 106 and the unbuffered IC 107, the potential fluctuation of a part of the resonant current loop is output from the output terminal 108 as a rectangular wave corresponding to the resonant frequency. With such a configuration, the magnetic permeability sensor 100 according to the present embodiment oscillates at a frequency corresponding to the inductance L, the resistance value R _P , and the electrostatic capacitance C of the first capacitor 103 and the second capacitor 104.

The inductance L also changes depending on the presence of the magnetic substance in the vicinity of the pattern coil 101 and its concentration. Therefore, the magnetic permeability in the space near the pattern coil 101 can be determined from the oscillation frequency of the magnetic permeability sensor 100. Further, as shown in FIG. 1, in designing the oscillation frequency of the magnetic permeability sensor 100 with high accuracy, the circuit resistance _RL generated by a signal line or the like constituting the circuit cannot be ignored. The frequency corresponding to the parameter value of each part constituting the magnetic permeability sensor 100 will be described in detail later.

  As described above, the magnetic permeability sensor 100 according to this embodiment has the pattern coil 101 and the pattern resistor 102 connected in series, so that the magnetic permeability of the space that opposes the plane on which the pattern coil 101 is formed is set to the temperature. It becomes possible to detect stably without depending.

  However, the magnetic permeability sensor 100 according to the present embodiment is used on the premise that there is no temperature difference between the pattern coil 101 and the pattern resistor 102, and if a temperature difference occurs between the two, the magnetic permeability is increased. Cannot be detected correctly. Therefore, the magnetic permeability sensor 100 according to the present embodiment is preferably used in an environment in which a temperature difference does not occur between the pattern coil 101 and the pattern resistor 102, but is not necessarily used in such an environment. It is not always done.

  For example, the magnetic permeability sensor 100 according to this embodiment is attached to a developing device in an electrophotographic image forming apparatus using a two-component developer as described above, and the toner in the developer inside the developing device. It is used as a toner density detector for measuring the density of toner. The developing device includes a conveying screw for conveying the developer in the developing device, and generates heat by friction between the conveying screw and the bearing. Therefore, when the magnetic permeability sensor 100 is attached to such a developing device and used as a toner concentration detector, the distance from the heat source differs between the pattern coil 101 and the pattern resistor 102 depending on the attachment mode, so that the transmitted heat is transmitted. The amount is also different, resulting in a temperature difference between the two.

  As described above, the magnetic permeability sensor 100 is preferably used in such an environment even though it is preferable to use it in an environment where no temperature difference occurs between the pattern coil 101 and the pattern resistor 102. Not necessarily.

  Therefore, in the present embodiment, the temperature between the pattern coil 101 and the pattern resistor 102 is maintained even when the magnetic permeability sensor 100 is attached to an apparatus such as a developing device having a heat source as described above or an apparatus. The pattern coil 101 and the pattern resistor 102 are attached so that the distance from the heat source is the same so as not to cause a difference. Thus, when the magnetic permeability sensor 100 is mounted so that the distance from the heat source is the same between the pattern coil 101 and the pattern resistor 102, there is no difference in the amount of heat transmitted, and there is a temperature difference between the two. No longer occurs. Therefore, according to the present embodiment, it is possible to improve the accuracy of magnetic permeability detection by the magnetic permeability sensor 100.

  Next, an overview of the magnetic permeability sensor 100 according to the present embodiment will be described with reference to FIGS. 2 and 3A to 3F. FIG. 2 is a perspective view showing an overview of the magnetic permeability sensor 100 according to the present embodiment. 3A to 3F are six views showing the magnetic permeability sensor 100 according to this embodiment. In FIG. 2, the surface on which the pattern coil 101 and the pattern resistor 102 described in FIG. 1 are formed, that is, the detection surface facing the space where the magnetic permeability is to be detected is directed to the upper surface.

  As shown in FIGS. 2 and 3A, the pattern resistor 102 connected in series with the pattern coil 101 is patterned on the detection surface on which the pattern coil 101 is formed. As described with reference to FIG. 1, the pattern coil 101 is a signal line pattern formed in a spiral shape on a plane. Further, the pattern resistor 102 is a signal pattern formed in a zigzag pattern on the plane, and the function of the magnetic permeability sensor 100 as described above is realized by these patterns, and FIG. 2 and FIG. ) And visually interesting patterns.

  A portion formed by the pattern coil 101 and the pattern resistor 102 is a magnetic permeability detecting unit in the magnetic permeability sensor 100 according to the present embodiment. When the magnetic permeability sensor 100 is attached to the developing device 212, the detection unit is attached so as to face a toner movement space described later.

  Further, as shown in FIGS. 3B to 3F, the first capacitor 103, the second capacitor 104, the feedback resistor 105, the unbuffer ICs 106 and 107, and the output terminal 108 described in FIG. Is formed on the surface opposite to the surface on which the pattern coil 101 and the pattern resistor 102 are formed.

  Thus, the magnetic permeability sensor 100 is brought into contact with the surface of the magnetic permeability sensor 100 so that the surface on which the pattern coil 101, which is a portion that exhibits the sensing function, is opposed to the space where the magnetic permeability is to be detected. It becomes possible to arrange.

  Further, on the surface on which these components are mounted, no electronic component or signal line is mounted on the portion where the pattern coil 101 and the pattern resistor 102 are formed on the back side. Thereby, it is possible to prevent the magnetic flux generated by other electronic components and signal lines from affecting the pattern coil 101 and the pattern resistor 102, and to improve the magnetic permeability detection accuracy.

  Next, a functional configuration of the controller 1 of the image forming apparatus 200 according to the present embodiment will be described with reference to FIG. FIG. 4 is a block diagram schematically showing a functional configuration of the controller 1 according to the present embodiment. As shown in FIG. 4, the controller 1 according to the present embodiment has the same configuration as an information processing apparatus such as a general PC (Personal Computer) or a server. That is, the controller 1 according to the present embodiment includes a CPU (Central Processing Unit) 10, a ROM (Read Only Memory) 20, a RAM (Random Access Memory) 30, a DMAC (Direct Memory Access Controller), and an ASIC Controller. ) 50, an input / output control ASIC 60 and a crystal oscillation circuit 70.

  The CPU 10 is a calculation means and controls the operation of the entire controller 1. The ROM 20 is a read-only nonvolatile storage medium and stores a program such as firmware. The RAM 30 is a volatile storage medium capable of reading and writing information at high speed, and is used as a work area when the CPU 10 processes information. The DMAC 40 controls direct access to the RAM 30 not via the CPU 10.

  The ASIC 50 functions as a connection interface between the system bus to which the CPU 10 and the RAM 30 are connected and other devices. The input / output control ASIC 60 acquires a detection signal output from the magnetic permeability sensor 100 and converts it into information that can be processed in the controller 1. That is, the magnetic permeability sensor 100 is used as a magnetic permeability detector. The crystal oscillation circuit 70 oscillates a reference clock for operating each device in the controller 1.

  Next, the functional configuration of the input / output control ASIC 60 in the controller 1 of the image forming apparatus 200 according to the present embodiment will be described with reference to FIG. FIG. 5 is a block diagram schematically showing a functional configuration of the input / output control ASIC 60 according to the present embodiment. As shown in FIG. 5, the input / output control ASIC 60 according to the present embodiment includes a counter 61, a read signal acquisition unit 62, and a count value output unit 63. The magnetic permeability sensor 100 according to the present embodiment is an oscillation circuit that outputs a rectangular wave having a frequency corresponding to the magnetic permeability in a space to be detected. The counter 61 is a counter that increments a value in accordance with a rectangular wave output from such a magnetic permeability sensor 100.

  The read signal acquisition unit 62 acquires a read signal that is an instruction to acquire the count value of the counter 61 from the CPU 10 via the ASIC 50. When the read signal is acquired from the CPU 10, the read signal acquisition unit 62 inputs a signal for causing the count value output unit 63 to output a count value. The count value output unit 63 outputs the count value of the counter 61 in accordance with the signal from the read signal acquisition unit 62.

  As shown in FIG. 5, the controller 1 includes a timer 11. The timer 11 outputs an interrupt signal to the CPU 10 every time the count value of the reference clock input from the crystal oscillation circuit 70 reaches a predetermined value. The CPU 10 outputs the above-described read signal in response to the interrupt signal input from the timer 11.

  Note that the CPU 10 accesses the input / output control ASIC 60 via, for example, a register. For this reason, the above-described read signal is performed by the CPU 10 writing a value in a predetermined register included in the input / output control ASIC 60. The count value is output by the count value output unit 63 when the count value is stored in a predetermined register included in the input / output control ASIC 60 and the CPU 10 acquires the value.

  Next, a mechanism for image formation output included in the image forming apparatus 200 according to the present embodiment will be described with reference to FIG. FIG. 6 is a side view showing a mechanism for image formation output included in the image forming apparatus 200 according to the present embodiment.

  As shown in FIG. 6, the image forming apparatus 200 according to the present embodiment includes a configuration in which image forming units 206 </ b> K to 206 </ b> Y for each color are arranged along a conveyor belt 205 that is an endless moving unit. It is said to be a tandem type. That is, along the transport belt 205, which is an intermediate transfer belt on which an intermediate transfer image is formed to be transferred from a paper feed tray 201 to a sheet (an example of a recording medium) 204 separated and fed by a paper feed roller 202. A plurality of image forming units (electrophotographic process units) 206Y, 206M, 206C, and 206K (hereinafter collectively referred to as image forming unit 206) are arranged in order from the upstream side of the conveying belt 205 in the conveying direction.

  The paper 204 fed from the paper feed tray 201 is stopped once by the registration rollers 203 and sent out to the image transfer position from the transport belt 205 in accordance with the image formation timing in the image forming unit 206.

  The plurality of image forming units 206Y, 206M, 206C, and 206K have the same internal configuration except that the colors of toner images to be formed are different. The image forming unit 206K forms a black image, the image forming unit 206M forms a magenta image, the image forming unit 206C forms a cyan image, and the image forming unit 206Y forms a yellow image. In the following description, the image forming unit 206Y will be described in detail. However, since the other image forming units 206M, 206C, and 206K are the same as the image forming unit 206Y, the image forming units 206M, 206C, and 206K are the same. For each of these components, instead of Y added to each component of the image forming unit 206Y, only the symbols distinguished by M, C, and K are displayed in the figure, and the description thereof is omitted.

  The conveyor belt 205 is an endless belt, that is, an endless belt that is stretched between a driving roller 207 and a driven roller 208 that are rotationally driven. The drive roller 207 is driven to rotate by a drive motor (not shown), and the drive motor, the drive roller 207, and the driven roller 208 function as a drive unit that moves the conveyance belt 205 that is an endless moving unit. .

  At the time of image formation, the first image forming unit 206Y transfers a yellow toner image to the conveyance belt 205 that is rotationally driven. The image forming unit 206Y includes a photoconductor drum 209Y as a photoconductor, a charger 210Y disposed around the photoconductor drum 209Y, an optical writing device 211, a developing device 212Y, a photoconductor cleaner 213Y, and a static eliminator (not shown). ) Etc. The optical writing device 211 is configured to irradiate the respective photoconductive drums 209Y, 209M, 209C, and 209K (hereinafter collectively referred to as “photosensitive drum 209”).

  In the image formation, the outer peripheral surface of the photosensitive drum 209Y is uniformly charged by the charger 210Y in the dark, and then writing is performed by light from the light source corresponding to the yellow image from the optical writing device 211. An electrostatic latent image is formed. The developing device 212Y is a developing device that visualizes the electrostatic latent image with yellow toner, whereby a yellow toner image is formed on the photosensitive drum 209Y.

  This toner image is transferred onto the conveyance belt 205 by the action of the transfer unit 215Y at a position (transfer position) where the photosensitive drum 209Y and the conveyance belt 205 are in contact with or closest to each other. By this transfer, an image of yellow toner is formed on the conveyor belt 205. After the transfer of the toner image is completed, the photosensitive drum 209Y is wiped away with unnecessary toner remaining on the outer peripheral surface by the photoconductor cleaner 213Y, and then is neutralized by the static eliminator and stands by for the next image formation.

  As described above, the yellow toner image transferred onto the conveying belt 205 by the image forming unit 206Y is conveyed to the next image forming unit 206M by driving the rollers of the conveying belt 205. In the image forming unit 206M, a magenta toner image is formed on the photosensitive drum 209M by a process similar to the image forming process in the image forming unit 206Y, and the toner image is superimposed and transferred onto the already formed yellow image. Is done.

  The yellow and magenta toner images transferred onto the conveyance belt 205 are further conveyed to the next image forming units 206C and 206K, and the cyan toner image formed on the photosensitive drum 209C and the photosensitive drum are subjected to the same operation. The black toner image formed on the body drum 209K is superimposed on the already transferred image and transferred. Thus, a full-color intermediate transfer image is formed on the conveyance belt 205.

  The sheets 204 stored in the sheet feeding tray 201 are sent out in order from the top, and the intermediate transfer image formed on the conveyance belt 205 is transferred at a position where the conveyance path is in contact with or closest to the conveyance belt 205. It is transferred onto the paper. As a result, an image is formed on the paper surface of the paper 204. The sheet 204 on which the image is formed on the sheet surface is further conveyed, and after the image is fixed by the fixing device 216, the sheet 204 is discharged outside the image forming apparatus.

  Further, a belt cleaner 218 is provided for the conveyor belt 205. As shown in FIG. 6, the belt cleaner 218 is a cleaning blade pressed against the conveyance belt 205 on the downstream side of the transfer position of the image from the conveyance belt 205 to the sheet 204 and upstream of the photosensitive drum 209. And a toner removing unit that scrapes off toner adhering to the surface of the transport belt 205.

  The image forming apparatus 200 having such a configuration is driven by being controlled by the controller 1 described with reference to FIG. In the configuration illustrated in FIG. 6, the developing device 212 is provided with the magnetic permeability sensor 100 according to the present embodiment.

  Next, the configuration of the developing device 212 according to the present embodiment will be described with reference to FIGS. FIG. 7 is a perspective view showing an overview of the developing device 212 according to the present embodiment. In FIG. 7, the state in which the developing device 212 is mounted on the image forming apparatus 200, that is, the state when the developing device 212 is used is shown upside down. FIG. 8 is a perspective view showing the inside of the developing device 212 according to this embodiment. 7 and 8 are shown upside down. Accordingly, FIG. 8 shows a state in which the developing device 212 is mounted on the image forming apparatus 200, that is, a state when the developing device 212 is in use. Further, the longitudinal direction of the developing device 212 shown in FIGS. 7 and 8 is a main scanning direction perpendicular to the drawing of FIG. 6, that is, parallel to the belt surface of the conveying belt 205 and perpendicular to the conveying direction of the conveying belt 205. Direction.

  FIG. 9 is a diagram showing a side cross section of the developing device 212 according to the present embodiment. 9 is a side sectional view of the developing device 212 shown in FIG. 7 when viewed from the left end portion in the main scanning direction. Further, FIG. 9 is shown upside down from the perspective view of FIG. That is, FIG. 9 shows the upper and lower sides of the perspective view of FIG. Accordingly, FIG. 9 shows a state in which the developing device 212 is mounted on the image forming apparatus 200, that is, a state when the developing device 212 is in use. FIG. 10 is a front view showing an overview of the developing device 212 according to the present embodiment. FIG. 10 is a front view of the developing device 212 according to the present embodiment when viewed from a direction parallel to the belt surface of the transport belt 205 and perpendicular to the main scanning direction, that is, the sub-scanning direction. . In FIG. 10, the state in which the developing device 212 is mounted on the image forming apparatus 200, that is, the state when the developing device 212 is used is shown upside down.

  As shown in FIGS. 7 to 10, the developing device 212 is provided with toner that is a nonmagnetic developer and a carrier that is magnetic particles, that is, carrier screws 212 b and 212 c that convey the developer. It has been. The conveying screw 212b is supported by bearings 212d and 212e, and the conveying screw 212c is supported by bearings 212f and 212g. Further, the conveying screw 212b and the conveying screw 212c are connected to a gear 212i and a gear 212j, respectively, and the gear 212i and the gear 212j are engaged with each other, and one of them rotates to rotate in the opposite direction. The conveying screws 212b and 212c rotate in opposite directions, so that the developer filled therein is spread over the entire main scanning direction described above inside the developing device 212. That is, the entire inside of the developing device 212 is used as a developer accommodating portion, the conveying screw 212b functions as a first developer conveying portion, the bearing 212d functions as a first bearing, and the conveying screw 212c is a second developer conveying portion. The bearing 212f functions as a second bearing.

  Further, as shown in FIG. 8, the developer conveyed by the conveying screws 212b and 212c inside the developing device 212 is conveyed at one end (left end toward FIG. 8) in the main scanning direction. Is transferred from the transfer path by the transfer path to the transfer path by the transfer screw 212c. Accordingly, the developer delivery space (hereinafter referred to as “toner movement space”) in which the developer moves between the respective transport paths at the end portion in the main scanning direction of the developing device 212 is the space where the developer is most concentrated. The magnetic permeability sensor 100 according to the present embodiment is used as a toner concentration detector by being attached to the sensor attachment surface 212a or 212h arranged to face the toner movement space.

  The reason why the magnetic permeability sensor 100 is attached to the sensor attachment surface 212a or 212h arranged to face the toner moving space will be described. The amount of change in the magnetic permeability increases as the developer density increases. For this reason, the magnetic permeability sensor 100 is attached at a position facing the toner movement space where the developer is most concentrated, so that the magnetic permeability of the space inside the developing device 212 can be detected more accurately.

  Although the change in magnetic permeability is large or small, the magnetic permeability sensor 100 does not necessarily have to be attached at the position 212a or 212h because the magnetic permeability change occurs in any space filled with the developer. In other words, the magnetic permeability sensor 100 can detect the magnetic permeability wherever it is attached so as to face the space filled with the developer. However, when the magnetic permeability sensor 100 is attached at a position facing the space where the developer concentration is low, the magnetic permeability detection accuracy is lowered. From this point of view, the magnetic permeability sensor 100 according to the present embodiment is attached to the sensor attachment surface 212a or 212h that is disposed to face the toner movement space.

  As shown in FIG. 8, the developer conveyed by the conveying screws 212b and 212c inside the developing device 212 is opposite to the above at the other end in the main scanning direction (right end as viewed in FIG. 8). Similarly, although it is a direction, it is passed from the conveyance path | route by the conveyance screw 212c to the conveyance path | route by the conveyance screw 212b. Accordingly, the space in which the developer moves between the respective conveyance paths at the end portion in the main scanning direction is the space where the developer is most concentrated, similarly to the toner movement space. Therefore, the magnetic permeability sensor 100 according to the present embodiment may be attached to face this space in addition to the toner moving space.

  As shown in FIGS. 7 and 9, the sensor mounting surfaces 212a and 212h are formed in a flat shape so that the magnetic permeability sensor 100 configured based on a flat substrate can be easily mounted. The magnetic permeability sensor 100 is attached to the developing device 212 by attaching the detection surface of the magnetic permeability sensor 100 so as to face each other. Further, as shown in FIG. 9, the housing of the developing device 212 is formed in an arc shape in accordance with a circle which is a cross-sectional shape of the two conveying screws 212b and 212c. The sensor mounting surfaces 212a and 212h are configured by molding a part of the casing formed in an arc shape on a plane as described above.

  As described above, since the sensor mounting surfaces 212a and 212h are formed by forming a part of the arcuate casing on a flat surface, the surface of the sensor mounting surfaces 212a and 212h in the developing device 212 and the developing device. The space | interval with the space inside 212 is narrow. In the present embodiment, the magnetic permeability sensor 100 is attached to the sensor attachment surface 212a or 212h configured as described above, whereby the magnetic permeability of the space inside the developing device 212 can be detected more suitably.

  In such a configuration, the developer used in the electrophotographic image forming apparatus includes a color developing powder (toner) and a developer for developing the electrostatic latent image on the photosensitive drum 209 by the developing device 212. A carrier, which is a granular magnetic material for conveying powder, is mixed. Accordingly, when the electrostatic latent image on the photosensitive drum 209 is developed with the toner in the developer, the density of the toner in the developer in the developer 212 fluctuates, and the space facing the sensor mounting surface 212a or 212h. The magnetic permeability at will change. By detecting the change by the magnetic permeability sensor 100, the toner concentration in the developer in the developing device 212 can be detected.

  Then, in order to spread the developer filled in the developing device 212 in the main scanning direction in the inside thereof, when the conveying screw 212b rotates, the friction portion is caused to be a heat source by friction with the bearing 212d. As heat is generated, it is radiated to the surroundings. For this reason, the temperature of the magnetic permeability sensor 100 attached to the sensor attachment surface 212a or 212h rises due to the radiated heat, but depending on the attachment mode, the pattern coil 101 and the pattern resistor 102 may be affected by the heat source. Since the distances are different, the amount of heat transferred is also different, and a temperature difference occurs between the two. Actually, frictional heat is generated using the frictional portion between the conveying screw 212b and the bearing 212d as a heat source. However, in the present embodiment, as shown in FIGS. 9 and 10, the center of the frictional portion is used as the heat source. I will handle it. Hereinafter, the heat source is referred to as a heat source 212k.

  As such a case, the magnetic permeability sensor 100 according to the present embodiment is attached to the sensor attachment surface 212h so that the connection direction of the pattern coil 101 and the pattern resistor 102 is parallel to the main scanning direction. This will be described with reference to FIGS. 11 to 13A and 13B. In the present embodiment, the connection direction is a direction connecting the center of the pattern coil 101 and the center of the pattern resistor 102 in the magnetic sensor 100. FIGS. 11A to 13A are diagrams illustrating an example of an attachment mode of the magnetic permeability sensor 100 according to the present embodiment to the developing device 212. FIG. FIG. 13B is a diagram showing the temperature distribution in the main scanning direction in the developing device 212 according to this embodiment.

  11 to 13A are all shown upside down with respect to the state in which the developing unit 212 is mounted on the image forming apparatus 200, that is, the state in which the developing unit 212 is used. 11, the left end portion of the developing device 212 in the perspective view shown in FIG. 7 is shown enlarged in a state where the magnetic permeability sensor 100 is attached. In FIG. 12, the developing device 212 according to this embodiment is shown in a side sectional view in a state where the magnetic permeability sensor 100 is attached. In FIG. 13A, the developing device 212 according to the present embodiment is arranged in a direction parallel to the belt surface of the conveyor belt 205 and perpendicular to the main scanning direction in a state where the magnetic permeability sensor 100 is attached. That is, it is a front view when viewed from the sub-scanning direction.

  In addition, a point 101a in FIG. 13A represents the center of the pattern coil 101 in the magnetic permeability sensor 100, and a point 102a represents the center of the pattern resistor 102 in the magnetic permeability sensor 100. In the following, when discussing the positional relationship between the pattern coil 101 and the pattern resistor 102, the point indicated by 101 a is treated as a reference point for representing the position of the pattern coil 101, and the point indicated by 102 a is represented by the position of the pattern resistor 102. It will be treated as a reference point.

  The heat generated in the heat source 212k is conducted through the housing of the developing unit 212 toward the main scanning direction which is the longitudinal direction of the developing unit 212. The amount of heat conduction at this time increases as the distance from the heat source 212k decreases, and decreases as the distance increases. Accordingly, when the developing device 212 according to the present embodiment starts operation and heat is generated in the heat source 212k due to friction between the conveying screw 212b and the bearing 212d, the temperature is higher as the distance from the heat source 212k is shorter, and as the distance increases. Lower.

  Therefore, as shown in FIGS. 11 to 13A, when the magnetic permeability sensor 100 is attached to the sensor attachment surface 212h so that the connection direction of the pattern coil 101 and the pattern resistor 102 is parallel to the main scanning direction. The distance from the heat source 212k differs between the reference point 101a and the reference point 102a. Therefore, in the case of such an attachment mode, as shown in FIG. 13B, a temperature difference is generated between the pattern coil 101 and the pattern resistor 102. Therefore, the magnetic permeability sensor 100 accurately determines the magnetic permeability. Cannot be detected.

  Therefore, in the present embodiment, the distance from the heat source 212k is the same between the pattern coil 101 and the pattern resistor 102 so that the magnetic permeability sensor 100 does not cause a temperature difference between the pattern coil 101 and the pattern resistor 102. It is characterized by being attached to the developing device 212 so that As described above, when the magnetic permeability sensor 100 is attached to the developing device 212 so that the distance from the heat source 212k is the same between the pattern coil 101 and the pattern resistor 102, there is no difference in the amount of heat transmitted. No temperature difference between them. Therefore, according to the present embodiment, it is possible to improve the accuracy of magnetic permeability detection by the magnetic permeability sensor 100.

  As described above, in the present embodiment, when discussing the positional relationship between the pattern coil 101 and the pattern resistor 102, the reference point 101a is treated as a reference point for representing the position of the pattern coil 101, and the reference point 102a is used as a pattern. It is treated as a reference point for representing the position of the resistor 102. Therefore, in the present embodiment, the distance from the heat source 212k is the reference when the magnetic permeability sensor 100 is attached to the developing device 212 so that the distance from the heat source 212k is the same between the pattern coil 101 and the pattern resistor 102. An example in which the magnetic permeability sensor 100 is attached to the developing device 212 so that the point 101a and the reference point 102a are the same will be described.

  Here, a specific example of how the magnetic permeability sensor 100 is attached to the developing device 212 in this embodiment will be described with reference to FIGS. 14-16 is a figure which shows an example of the attachment aspect to the developing device 212 of the magnetic permeability sensor 100 in this embodiment. 14 to 16 are all shown upside down with respect to the state in which the developing device 212 is mounted on the image forming apparatus 200, that is, the state in which the developing device 212 is used.

  In FIG. 14, the left end portion of the developing device 212 in the perspective view shown in FIG. 7 is shown enlarged in a state where the magnetic permeability sensor 100 is attached. In FIG. 15, the toner movement space of the developing device 212 according to the present embodiment is shown in a side sectional view in a state where the magnetic permeability sensor 100 is attached. In FIG. 16, the developing device 212 according to the present embodiment is arranged in a direction parallel to the belt surface of the transport belt 205 and perpendicular to the main scanning direction, that is, the sub-scanner in a state where the magnetic permeability sensor 100 is attached. It is a front view at the time of seeing from a scanning direction.

  As shown in FIGS. 14-16, in this embodiment, the magnetic permeability sensor 100 is attached to the sensor attachment surface 212a so that the distance from the heat source 212k is the same at the reference point 101a and the reference point 102a. Therefore, in this embodiment, a temperature difference does not occur between the pattern coil 101 and the pattern resistor 102, so that the accuracy of magnetic permeability detection by the magnetic permeability sensor 100 can be improved.

  Thus, in the present embodiment, the magnetic permeability sensor 100 has a distance from the heat source 212k of the pattern coil 101 and the pattern resistor 102 so that no temperature difference occurs between the pattern coil 101 and the pattern resistor 102. It is characterized by being attached to the developing device 212 so as to be the same. Therefore, according to the present embodiment, a temperature difference does not occur between the pattern coil 101 and the pattern resistor 102, and it is possible to improve the accuracy of magnetic permeability detection by the magnetic permeability sensor 100.

  Next, a method of counting the oscillation frequency of the magnetic permeability sensor 100 according to this embodiment will be described with reference to FIG. FIG. 17 is a diagram showing an aspect of the count value of the magnetic permeability sensor 100 counted by the function of the input / output control ASIC 60 according to the present embodiment. If there is no change in the concentration of the magnetic substance present around the magnetic permeability sensor 100, the magnetic permeability sensor 100 continues to oscillate at the same frequency in principle. As a result, as shown in FIG. 17, the count value of the counter 61 increases uniformly with time.

When an interrupt signal is input from the timer 11 to the CPU 10, the CPU 10 outputs a read signal to the input / output control ASIC 60, and the count value of the counter 61 at that timing is acquired by the CPU 10. As shown in FIG. 17, count values such as aaaah, bbbbbh, cccch, ddddh, AAAAh are acquired at timings t ₁ , t ₂ , t ₃ , t ₄ , t ₅ .

When the CPU 10 acquires the count value at each timing, the CPU 10 calculates the frequency in each of the periods T ₁ , T ₂ , T ₃ , and T ₄ shown in FIG. The timer 11 according to the present embodiment outputs an interrupt signal when a reference clock corresponding to 2 (msec) is counted. Therefore, the CPU 10 divides the count value of the counter 61 in each period by 2 (msec) to thereby oscillate the permeability sensor 100 in each period T ₁ , T ₂ , T ₃ , and T ₄ shown in FIG. f (Hz) is calculated.

Moreover, as shown in FIG. 17, the upper limit of the count value of the counter 61 according to the present embodiment is FFFFh. Therefore, CPU 10 may, when calculating the frequency in the period _{T 4,} a value obtained by subtracting ddddh from FFFFh, calculates the oscillation frequency f (Hz) by dividing the sum of the values of the AAAAh in 2 (msec).

  Next, another method for counting the oscillation frequency of the magnetic permeability sensor 100 according to this embodiment will be described with reference to FIG. FIG. 18 is a diagram showing another aspect of the count value of the magnetic permeability sensor 100 counted by the function of the input / output control ASIC 60 according to the present embodiment. In the case of FIG. 18, in the input / output control ASIC 60, the counter 61 resets the count value after the count value is read by the count value output unit 63. In this reset process, the count value output unit 63 may input a reset signal to the counter 61 after the count value is read, or the specification of the counter 61 has a function that is reset every time the count value is read. It may be provided.

In the case of the aspect of FIG. 18, the count value acquired at each timing is a value counted in each period T ₁ , T ₂ , T ₃ , T ₄ . Therefore, the CPU 10 calculates the oscillation frequency f (Hz) by dividing the count value acquired at each timing by 2 (msec).

  Thus, in the controller 1 according to the present embodiment, the frequency of the signal oscillated by the magnetic permeability sensor 100 is acquired, and an event corresponding to the oscillation frequency of the magnetic permeability sensor 100 can be determined based on the acquisition result. it can. In the magnetic permeability sensor 100 according to the present embodiment, the inductance L changes according to the concentration of the magnetic material existing in the space where the coil surfaces of the pattern coil 101 face each other, and as a result, a signal output from the output terminal 108 The frequency of changes. As a result, the controller 1 can detect the concentration of the magnetic substance existing in the space where the coil surfaces of the pattern coil 101 face each other.

  Such a magnetic permeability sensor 100 oscillates at a frequency corresponding to the concentration of the magnetic material in a predetermined space as described above. The crystal oscillation circuit 70 oscillates at a predetermined frequency. However, they all have a temperature characteristic in which the oscillation frequency varies depending on the temperature of the use environment.

  Here, the temperature characteristics of the oscillation frequency of the crystal oscillation circuit 70 according to the present embodiment will be described with reference to FIG. FIG. 19 is a graph showing a temperature characteristic graph of the crystal oscillation circuit 70. As shown in FIG. 19, the crystal oscillation circuit 70 has a parabolic temperature characteristic having a peak at a certain temperature.

  In the controller 1, in order to detect the concentration of the magnetic material in the predetermined space with high accuracy based on the frequency of the signal oscillated by the magnetic permeability sensor 100, the change in the oscillation frequency according to the temperature variation should be as small as possible. preferable. As described above, the calculation of the oscillation frequency in the controller 1 is performed by obtaining a count value every 2 (msec) counted by the timer 11 and dividing the count value by 2 (msec).

  Here, since the timer 11 counts 2 (msec) based on the reference clock input from the crystal oscillation circuit 70, if the oscillation frequency of the crystal oscillation circuit 70 fluctuates due to temperature characteristics as shown in FIG. As long as the count values for (msec) are the same, the count period for 2 (msec) varies. As a result, an error occurs in the oscillation frequency of the magnetic permeability sensor 100 calculated by the CPU 10.

  On the other hand, if the temperature characteristic of the magnetic permeability sensor 100 is similar to the temperature characteristic of the crystal oscillation circuit 70 as shown in FIG. 19, it is possible to cancel the oscillation frequency calculation error as described above. is there. That is, even if the oscillation frequency of the crystal oscillation circuit 70 varies due to temperature variation, if the oscillation frequency of the magnetic permeability sensor 100 also varies in the same way, the count counted by the counter 61 in the count period of 2 (msec). Since the fluctuation of the value is reduced, the error of the oscillation frequency of the finally calculated permeability sensor 100 can be reduced.

For this purpose, it is required to arbitrarily adjust the temperature characteristic of the oscillation frequency of the magnetic permeability sensor 100. Here, the oscillation frequency of the LC oscillation circuit will be described. The oscillation frequency of the conventional LC oscillation circuit obtained by removing the pattern resistor 102 from the LC oscillation circuit shown in FIG. 1 is expressed by the following equation (1).

Therefore, in order to adjust the temperature characteristic of the oscillation frequency of the magnetic permeability sensor 100, the respective parameters “L”, “C”, and “R _L ” included in the equation (1) are adjusted. Here, the temperature characteristics of the inductance L of the pattern coil 101 according to the present embodiment will be described with reference to FIG. 20, and the temperature characteristics of the capacitance C of the first capacitor 103 and the second capacitor 104 according to the present embodiment. Will be described with reference to FIG. 21, and the temperature characteristics of the circuit resistance _{RL according} to the present embodiment will be described with reference to FIG.

FIG. 20 is a diagram illustrating a temperature characteristic graph of the inductance L of the pattern coil 101 according to the present embodiment. FIG. 21 is a diagram illustrating a temperature characteristic graph of the capacitance C of the first capacitor 103 and the second capacitor 104 according to the present embodiment. FIG. 22 is a diagram illustrating a temperature characteristic graph of the circuit resistance _{RL according} to the present embodiment.

As shown in FIG. 20, the inductance L of the pattern coil 101 has a characteristic of increasing as the temperature rises. Further, as shown in FIG. 21, the capacitances C of the first capacitor 103 and the second capacitor 104 have a characteristic of decreasing as the temperature rises. Further, as shown in FIG. 22, the circuit resistance _RL has a characteristic of increasing as the temperature rises.

  If each parameter can be adjusted based on such a temperature characteristic, the temperature characteristic of the magnetic permeability sensor 100 can be improved, that is, the fluctuation of the oscillation frequency with respect to the temperature change can be reduced. It becomes possible to match the temperature characteristics of the crystal oscillation circuit 70 as described.

However, among the parameters included in the equation (1), “R _L ” is a parameter that is difficult to adjust independently. Further, since the value of “R _L ” is affected by “L”, it is difficult to adjust “R _L ” and “L” independently. Also, considering the oscillation frequency of the magnetic permeability sensor 100, it is difficult to adjust the value of “C” independently of the other parameters.

In contrast, in the magnetic permeability sensor 100 according to this embodiment, by inserting a pattern resistor 102 in series resonance current loop, the oscillation of the magnetic permeability sensor 100 by adjusting the resistance value R _P of the pattern resistors 102 Adjust the temperature characteristics of frequency. Since the resistance value _RP is a parameter that can be adjusted independently without being restricted as described above, such temperature characteristics can be adjusted.

First, a description will be given of the principle that by adjusting the resistance value R _P of the pattern resistors 102 can adjust the temperature characteristic of the magnetic permeability sensor 100. The above equation (1) is an equation obtained by solving a part of the equation representing the impedance of the circuit in the resonance current loop with respect to the angular velocity ω under the condition that the impedance of the circuit in the resonance current loop is minimized. Therefore, when Expression (1) is transformed into an expression indicating a condition that minimizes the impedance of the circuit in the resonance current loop, the following Expression (2) is obtained.

The formula (2) are the expressions not contain a pattern resistor 102, based on the equation (2), wherein the resistance value R _P of the pattern resistors 102, wherein indicating the impedance of the resonant current loop below Equation (3) is obtained.

Here, the frequency characteristic of the inductance of the pattern resistor 102 according to the present embodiment will be described with reference to FIG. FIG. 23 is a graph showing a result of measuring the inductance of the pattern resistor 102 by changing the frequency. As shown in FIG. 23, the pattern resistor 102 has an inductance component due to the magnetic flux generated by the zigzag pattern, and the inductance is a value of about 13 (nH), for example, around 3 × 10 ⁶ (Hz). . Therefore, Z _RP in the above formula (3) is expressed by the following formula (4), where the inductance component of the pattern resistor 102 is L _RP .

Then, based on the above equation (3), the following equation (5) is satisfied under the condition that the impedance Z is minimized.

When the oscillation frequency f _{0 of the} circuit shown in FIG. 1 is obtained based on the above equation (5), the following equation (6) is obtained.

In the above equation (6), it is difficult to adjust the values of “R _L ”, “L”, and “C”, but L _RP can be adjusted independently of other parameters. As described in FIG. 20, in general, the response of the inductance to the temperature fluctuation is proportional. As a result, the value of _LRP acts on the oscillation frequency in the direction of decreasing the frequency as the temperature increases. Therefore, by causing the temperature characteristic determined by the part other than _LRP in Equation (6) to act in the direction of increasing the frequency with respect to the temperature rise, the temperature characteristic can be stabilized over a wide temperature range. Become.

Here, as shown in FIG. 23 and the above equation (4), since the pattern resistor 102 has an inductance component, the inductance value L _RP changes due to a change in the surrounding magnetic permeability like the pattern coil 101. Can be considered. As a result, it can be considered that the range of the sensing unit by the pattern coil 101 is synonymous with the fact that the range of the pattern resistor 102 is expanded. This point will be described with reference to FIGS.

FIG. 24A is a diagram showing how the pattern resistor 102 is formed, and FIGS. 24B and 24C are cross-sectional views taken along the cutting line AA in FIG. As shown in FIG. 24B, when a current flows through the pattern resistor 102, a magnetic flux as indicated by a broken line in the figure is generated. As a result, the magnetic flux between the adjacent patterns is strengthened, and as a result, as shown in FIG. 24B, magnetic flux is generated in the alternate direction between the adjacent patterns in the zigzag pattern. The magnetic flux is able to produce an inductance value L _RP pattern resistor 102.

  Here, as shown in FIG. 24B, when a change occurs in the magnetic permeability in the influence range of the generated magnetic flux, the inductance component due to the magnetic flux generated between the patterns also changes. However, as shown in FIG. 24 (c), among the magnetic fluxes generated between the patterns, the signs of the magnetic permeability change component in the magnetic flux in one direction and the magnetic permeability change component in the magnetic flux in the opposite direction are Since the direction of the magnetic flux is different, the positive and negative are reversed and canceled.

  As a result, the inductance component in the entire pattern resistor 102 does not change even if the surrounding magnetic permeability changes. That is, the pattern resistor 102 is not affected by the surrounding magnetic permeability, and can be used as an inductor having no sensing function for the magnetic permeability. The magnetic permeability sensor 100 according to the present embodiment adjusts the temperature characteristic of the oscillation frequency by inserting the pattern resistor 102 in series with the pattern coil 101 in the resonance current loop and adjusting the resistance value of the pattern resistor 102. Even if the pattern resistor 102 has a sensing function for the surrounding magnetic permeability, there is no problem.

  Therefore, providing the pattern resistor 102 in the resonance current loop as shown in FIG. 1 does not mean that the range of the sensing portion by the pattern coil 101 is expanded by the mounting range of the pattern resistor 102. In other words, by providing the zigzag pattern resistor 102, it is possible to provide an inductance component unrelated to the magnetic permeability sensing function in the LC oscillation circuit used as the magnetic permeability sensor.

Here, by changing to various values of the inductance value L _RP pattern resistor 102 in the circuit shown in FIG. 1 shows the result of measuring the change in frequency with respect to temperature variations in FIG 25 (a) ~ (d) . _25A to _25D , L _RP1 <L _RP2 <L _RP3 <L _RP4 . As shown in FIGS. 25 (a) to 25 (d), the larger the inductance value of the pattern resistor 102, the lower the peak, that is, the extreme temperature at a frequency that changes in a parabolic manner with respect to temperature fluctuation. I understand. Therefore, by adjusting the inductance value L _RP pattern resistor 102, it can be seen that it is possible to adjust the temperature characteristic of the oscillation frequency of the magnetic permeability sensor 100.

Here, an example of a method for adjusting the inductance component of the pattern resistor 102 will be described with reference to FIG. FIGS. 26A to 26D are diagrams showing how the pattern resistors 102 corresponding to L _{RP1 to} L _RP4 shown in FIGS. _30A to _30D are formed. As shown in FIGS. 26A to 26D, the inductance value can be increased by increasing the number of spells that are the shape of the pattern resistor 102. Thus, by using the zigzag pattern resistor 102, in addition to the effect that the temperature characteristics can be adjusted as shown in FIGS. 26A to 26D, the temperature characteristics can be adjusted. There is also an effect that the adjustment of the inductance value can be easily realized only by changing the number of folds.

  Further, in the experimental result, the pattern is such that the temperature at the parabolic peak in the temperature characteristic as shown in FIGS. 26A to 26D matches the parabolic peak in the temperature characteristic of the crystal oscillation circuit 70 shown in FIG. When the resistor 102 was formed, the resistance value of the pattern resistor was 0.3 (Ω). In that case, the frequency fluctuation in the range of 10 to 50 (° C.), which is the temperature range of the assumed usage environment, results in ± 37 (ppm: part per million), which is a favorable temperature fluctuation compared to the prior art. Was obtained, and the result generally matched ± 10 to 40 (ppm), which is the frequency fluctuation range of the crystal oscillation circuit 70.

  Thus, in the present embodiment, a magnetic permeability sensor using an LC oscillation circuit that can easily adjust the temperature characteristic of the oscillation frequency can be provided by inserting the pattern resistor 102 in series in the resonance current loop. .

  In the present embodiment, the magnetic permeability sensor 100 that detects the magnetic permeability of a predetermined space by using the pattern coil 101 and the pattern resistor 102 has been described. On the other hand, assuming that the permeability in the range affecting the inductance of the pattern coil 101 of the sensor shown in FIG. 2 is constant, the oscillation frequency fluctuation of the circuit shown in FIG. Only the fluctuation component with respect to the temperature as described in (d) is provided.

  Therefore, the magnetic permeability sensor 100 described in the present embodiment can be used not only as a magnetic permeability sensor but also as a temperature sensor. In this case, as the temperature characteristics described with reference to FIGS. 25A to 25D, it is preferable to select a temperature characteristic that is simply increased or decreased in the temperature range to be detected. Thereby, it becomes possible to detect the temperature of the portion where the sensor is installed with a simple calculation based on the oscillation frequency of the sensor. Also from this point of view, it is significant that the temperature characteristic of the oscillation frequency of the circuit can be adjusted by adjusting the pattern resistor 102 as described above.

  Further, in the present embodiment, as described in FIGS. 26A to 26D, the case where a spell pattern composed only of straight lines and right angles is used as the pattern resistor 102 has been described as an example. However, this is only an example, and various patterns can be considered as the spelling pattern. For example, as shown in FIG. 27A, a zigzag folding pattern composed of a curve, or as shown in FIG. 27B, a zigzag folding pattern composed of a straight line and an acute angle can be used. Further, as shown in FIGS. 27C and 27D, a pattern in which the angle of the mountain constituting the spelled pattern shown in FIGS. 27A and 27B is inclined can be used.

  As described above, in the present embodiment, in the magnetic permeability sensor 100, the distance from the heat source 212k is set to the pattern coil 101 and the pattern so that no temperature difference is generated between the pattern coil 101 and the pattern resistor 102. It is characterized by being attached to the developing device 212 so as to be the same as the resistor 102. As described above, when the magnetic permeability sensor 100 is attached to the developing device 212 so that the distance from the heat source 212k is the same between the pattern coil 101 and the pattern resistor 102, there is no difference in the amount of heat transmitted. No temperature difference between them. Therefore, in the present embodiment, it is possible to improve the accuracy of magnetic permeability detection by the magnetic permeability sensor 100.

  In the present embodiment, as described above, an example in which the center of the friction part is handled as a heat source will be described. However, the present invention is not limited to this, and the conditions such as the ease of handling the heat source, the shape of the developing device 212, the temperature of the heat source, etc. Accordingly, an arbitrary point in the friction portion, an arbitrary point in the bearing 212d, an intersection of a straight line passing through the rotation center of the conveying screw 212b and a plane perpendicular to the straight line and intersecting the bearing 212d, the conveying screw 212b. Alternatively, the intersection of the straight line passing through the rotation center and the housing of the developing device 212 on the bearing 212d side may be handled as a heat source.

  Further, when there are two heat sources in the developing device 212, the midpoint of the line segment connecting them may be handled as a new heat source. When there are three or more heat sources in the developing device 212, the polygonal center formed by connecting the heat sources so that the line segments do not intersect with each other may be handled as a new heat source. Further, when there are four or more heat sources in the developing device 212, the point where the number of intersections of the line segments connecting the heat sources is the largest may be handled as a new heat source. However, the present invention is not limited to these, and it may be set as appropriate according to conditions such as ease of handling the heat source, the shape of the developing device 212, the temperature of each heat source, and the like.

  Further, when there are heat sources at a plurality of locations in the developing device 212 and the temperature is different even at one of them, a new heat source may be set in consideration of those temperatures. Specifically, for example, after moving each heat source according to its temperature, a plurality of heat sources can be used as one heat source in the same manner as described above, or a plurality of heat sources can be used as one heat source. In addition, a method of moving the heat source in one place according to the temperature of each heat source to be a new heat source is conceivable, but not limited to this, the handling of the heat source, the shape of the developing device 212, What is necessary is just to set suitably according to conditions, such as the temperature of each heat source.

  When there are heat sources at a plurality of locations in the developing device 212, the total distance from the center of the pattern coil 101 to each heat source in the magnetic permeability sensor 100 and the distance from the center of the pattern resistor 102 in the magnetic permeability sensor 100 to each heat source. Even if the magnetic permeability sensor 100 is attached to the developing device 212 so that the total sum of the two becomes equal, it is possible to obtain the same effects as those described in the present embodiment.

  In this embodiment, the magnetic permeability sensor 100 is attached to the sensor attachment surface 212a as shown in FIGS. 14 to 16 so that the distance from the heat source 212k is the same at the reference point 101a and the reference point 102a. An example was given. In addition, as long as the distance from the heat source 212k is the same at the reference point 101a and the reference point 102a, the magnetic permeability sensor 100 is in the state shown in FIGS. 14 to 16, as shown in FIGS. May be attached to the sensor attachment surface 212a in an inverted state. Here, FIGS. 28 to 30 are diagrams respectively corresponding to FIGS. 14 to 16 in a state where the magnetic permeability sensor 100 according to the present embodiment is attached to the developing device 212.

  In this embodiment, the magnetic permeability sensor 100 is attached to the sensor attachment surface 212a as shown in FIGS. 14 to 16 so that the distance from the heat source 212k is the same at the reference point 101a and the reference point 102a. An example was given. In addition, as long as the distance from the heat source 212k is the same at the reference point 101a and the reference point 102a, the magnetic permeability sensor 100 can be attached to the sensor attachment surface 212h in the state shown in FIGS. good. Here, FIGS. 31 to 33 correspond to FIGS. 14 to 16, respectively, in a state where the magnetic permeability sensor 100 according to the present embodiment is attached to the developing device 212.

  In this embodiment, the example in which the magnetic permeability sensor 100 is attached to the developing device 212 so that the distance from the heat source 212k is the same at the reference point 101a and the reference point 102a has been described. Even if there is a difference in the distance between them, if the distance is equal to or less than a predetermined value, it is sufficient to obtain the same effect as that described in the present embodiment. Here, when the difference between the distance from the heat source 212k to the reference point 101a and the distance from the heat source 212k to the reference point 102a is equal to or less than a predetermined value, it may be equal to or less than the distance from the reference point 101a to the reference point 102a. However, the smaller the difference between these distances, the greater the effect.

Embodiment 2. FIG.
In the first embodiment, the example in which the magnetic permeability sensor 100 is attached to the developing device 212 so that the distance from the heat source 212k is the same at the reference point 101a and the reference point 102a has been described. In this case, since a temperature difference does not occur between the pattern coil 101 and the pattern resistor 102, it is possible to improve the accuracy of magnetic permeability detection by the magnetic permeability sensor 100.

  However, the distance from the heat source 212k is not exactly the same between the reference point 101a and the reference point 102a, and even if there is a difference between these distances, if the distance is within a predetermined value, the same effect as described in the first embodiment is obtained. It is enough to get an effect. Further, as shown in FIG. 2 and FIG. 3A, the pattern coil 101 and the pattern resistor 102 have different sizes of occupied areas on the detection surface, and the distance from the heat source 212k is the reference point 101a and the reference point 102a. , The temperature difference between the pattern coil 101 and the pattern resistor 102 does not necessarily occur.

  Therefore, in the present embodiment, first, of the pattern coil 101 and the pattern resistor 102, the farthest away from the heat source 212k in the formation region having the larger occupied area on the detection surface of the magnetic permeability sensor 100. A straight line L that is perpendicular to the line segment B connecting the farthest point A and the heat source 212k and passes through the farthest point A is defined. Then, in the plane including the sensor mounting surface 212a or 212h, the magnetic permeability sensor of either the pattern coil 101 or the pattern resistor 102 is formed in the region on the heat source 212k side among the regions divided by the straight line L. The magnetic permeability sensor 100 is attached to the developing device 212 so as to include at least a part of a formation region having a smaller occupation area on the detection surface in 100.

  When the magnetic permeability sensor 100 is attached to the developing device 212 in this way, the difference in distance between the reference point 101a from the heat source 212k and the reference point 102a is within a predetermined value, and the pattern coil 101 and the pattern resistor 102 Even when the size of the occupied area on the detection surface is different, it is possible to obtain the same effect as the effect described in the first embodiment. Hereinafter, it will be described in detail with reference to the drawings. In addition, about the structure which attaches | subjects the code | symbol similar to Embodiment 1, it shall show the same or an equivalent part, and abbreviate | omits detailed description.

  First, the manner in which the magnetic permeability sensor 100 according to this embodiment is attached to the developing device 212 will be described with reference to FIG. FIG. 34 is a diagram illustrating an example of a manner of attaching the magnetic permeability sensor 100 to the developing device 212 in the present embodiment. 34 shows the state in which the developing device 212 is mounted on the image forming apparatus 200, that is, the state in which the developing device 212 is used in an upside down manner. Further, in FIG. 34, the developing device 212 according to the present embodiment is arranged in a direction parallel to the belt surface of the transport belt 205 and perpendicular to the main scanning direction, that is, the sub-scanner, in a state where the magnetic permeability sensor 100 is attached. It is a front view at the time of seeing from a scanning direction.

  As shown in FIG. 34, in this embodiment, first, the farthest point A farthest from the heat source 212k and the heat source 212k in the formation area of the pattern coil 101 on the detection surface of the magnetic permeability sensor 100 are set. A straight line L perpendicular to the connecting line segment B and passing through the farthest point A is defined. Then, in the plane including the sensor mounting surface 212a, the magnetic permeability sensor so that the region on the heat source 212k side of the region divided and formed by the straight line L includes at least part of the formation region of the pattern resistor 102. 100 is attached to the developing device 212.

  As described above, in the present embodiment, the magnetic permeability sensor 100 has at least a region where the pattern resistor 102 is formed in a region on the heat source 212k side in a region divided by the straight line L in a plane including the sensor mounting surface 212a. It is characterized in that it is attached to the developing device 212 so as to be partially included. Therefore, in the present embodiment, a temperature difference is unlikely to occur between the pattern coil 101 and the pattern resistor 102, so that the accuracy of magnetic permeability detection by the magnetic permeability sensor 100 can be improved.

  However, in the plane including the sensor mounting surface 212a, the magnetic permeability sensor 100 is developed so that the region on the heat source 212k side of the region divided by the straight line L includes the entire region where the pattern resistor 102 is formed. When configured to be attached to the vessel 212, it is more meaningful to obtain the effects described in the present embodiment. In addition, the region where the pattern resistor 102 is formed in the magnetic permeability sensor 100 is formed in the region on the heat source 212k side of the region divided by the straight line L so that the region where the pattern resistor 102 is formed and the line part B do not intersect. Even if the magnetic permeability sensor 100 is configured to be attached to the developing device 212 so that everything is included, it is more meaningful to obtain the effects described in the present embodiment.

  In the present embodiment, the case where the pattern coil 101 occupies a larger area on the detection surface than the pattern resistor 102 has been described as an example, but the same applies to the opposite case.

  In the present embodiment, the case where the magnetic permeability sensor 100 is attached to the sensor attachment surface 212a has been described, but the same applies to the case where the magnetic permeability sensor 100 is attached to the sensor attachment surface 212h.

Other embodiments.
In the above embodiment, an example in which the magnetic permeability sensor 100 is attached to the developing device 212 so that the distance from the heat source 212k is the same at the reference point 101a and the reference point 102a or equal to or less than a predetermined value. explained. In this case, since the temperature difference between the pattern coil 101 and the pattern resistor 102 does not occur or hardly occurs, the permeability detection accuracy by the permeability sensor 100 can be improved.

  In the present embodiment, a mounting mode in which the mounting mode is generalized so as to cover the mounting mode of the magnetic permeability sensor 100 described in the above embodiment to the developing device 212 will be described. Therefore, a manner of attaching the magnetic permeability sensor 100 in the present embodiment to the developing device 212 will be described with reference to FIG. FIG. 35 is a diagram illustrating an example of a manner of attaching the magnetic permeability sensor 100 to the developing device 212 in the present embodiment. FIG. 35 shows the state in which the developing device 212 is mounted on the image forming apparatus 200, that is, the state in which the developing device 212 is used in an upside down manner. In FIG. 35, the developing device 212 according to the present embodiment is arranged in a direction parallel to the belt surface of the conveyance belt 205 and perpendicular to the main scanning direction, that is, the sub-scanning direction, that is, the sub-scanning direction. It is a front view at the time of seeing from a scanning direction.

  As shown in FIG. 35, in the present embodiment, in a plane including the sensor mounting surface 212a, a straight line C passing through the reference point 101a and the heat source 212k, and a straight line D passing through the reference point 101a and the reference point 102a. The permeability sensor 100 is attached to the developing device 212 so that an acute angle E among the formed angles is within a predetermined angle.

  Thus, in this embodiment, the magnetic permeability sensor 100 is characterized in that it is attached to the developing device 212 so that the angle E is within a predetermined angle. Such a mounting mode is a generalized mounting mode so as to cover the mounting mode of the magnetic permeability sensor 100 described in the first and second embodiments to the developing device 212. Therefore, in the present embodiment, it is possible to obtain the same effects as those described in the first and second embodiments. In other words, in the present embodiment, the temperature difference between the pattern coil 101 and the pattern resistor 102 does not occur or hardly occurs, and therefore, the permeability detection accuracy by the permeability sensor 100 can be improved. .

  Here, as the angle E according to the present embodiment, in order to obtain the above effect, it is sufficient if it is larger than 0 degree and smaller than 180, but is preferably 30 degrees to 150 degrees, more preferably 60 degrees to If it is 120 degree | times, it will become more effective.

  In the present embodiment, in a plane including the sensor mounting surface 212a, an acute angle of angles formed by a straight line C passing through the reference point 101a and the heat source 212k and a straight line D passing through the reference point 101a and the reference point 102a. The example in which the magnetic permeability sensor 100 is attached to the developing device 212 so that the angle E is within a predetermined angle has been described. In addition, as shown in FIG. 36, an acute angle G among the angles formed by the straight line F passing through the reference point 102a and the heat source 212k and the straight line D passing through the reference point 101a and the reference point 102a is a predetermined angle. The magnetic permeability sensor 100 may be attached to the developing device 212 so as to be inside. The angle G in this case is the same as the angle E described in FIG.

  FIG. 36 is a diagram showing an example of another attachment mode of the magnetic permeability sensor 100 to the developing device 212 in the present embodiment. 36 shows the state in which the developing device 212 is mounted on the image forming apparatus 200, that is, the state in which the developing device 212 is used in an upside down manner. Also, in FIG. 36, the developing device 212 according to the present embodiment is arranged in a direction parallel to the belt surface of the transport belt 205 and perpendicular to the main scanning direction, that is, the sub-scanner, in a state where the magnetic permeability sensor 100 is attached. It is a front view at the time of seeing from a scanning direction.

  In the present embodiment, the case where the magnetic permeability sensor 100 is attached to the sensor attachment surface 212a has been described, but the same applies to the case where the magnetic permeability sensor 100 is attached to the sensor attachment surface 212h.

  In the above embodiment, the magnetic permeability sensor 100 is developed in the electrophotographic image forming apparatus 200 that uses a two-component developer in which a carrier that is magnetic particles and a toner that is a non-magnetic developer are mixed. However, the present invention is not limited to this, but the present invention is not limited to this, and the pattern coil 101 and the pattern resistor are used as a toner concentration detector that measures the concentration of toner in the developer inside the developer 212. The present invention can be similarly applied to any magnetic permeability detector that detects the magnetic permeability of a predetermined space facing the plane on which the LC oscillation circuit including 102 is formed.

  Moreover, in the said embodiment, the magnetic permeability sensor 100 which detects the magnetic permeability of predetermined space by using the pattern coil 101 and the pattern resistance 102 was demonstrated. On the other hand, assuming that the permeability in the range affecting the inductance of the pattern coil 101 of the sensor shown in FIG. 2 is constant, the oscillation frequency fluctuation of the circuit shown in FIG. Only the fluctuation component with respect to the temperature as described in (d) is provided.

  Therefore, the magnetic permeability sensor 100 described in the above embodiment can be used not only as a magnetic permeability sensor but also as a temperature sensor. In this case, as the temperature characteristics described with reference to FIGS. 25A to 25D, it is preferable to select a temperature characteristic that is simply increased or decreased in the temperature range to be detected. Thereby, it becomes possible to detect the temperature of the portion where the sensor is installed with a simple calculation based on the oscillation frequency of the sensor. Thus, when the magnetic permeability sensor 100 described in the above embodiment is used as a temperature sensor, for example, heat generation in the developing device 212 can be monitored, and excessive heat generation due to a failure or the like can be detected. Become.

  Even when the magnetic permeability sensor 100 is used as a temperature sensor in this way, as described in the above embodiment, the temperature difference between the pattern coil 101 and the pattern resistor 102 does not occur or hardly occurs. In addition, since the magnetic permeability sensor 100 is attached to the developing device 212, the accuracy of temperature detection can be improved. Therefore, even when the magnetic permeability sensor 100 is used as a temperature sensor, it is meaningful to apply the aspect of attaching the magnetic permeability sensor 100 described in the above embodiment to the developing device 212.

1 Controller 10 CPU
11 Timer 20 ROM
30 RAM
40 DMAC
50 ASIC
60 I / O control ASIC
61 Counter 62 Read signal acquisition unit 63 Count value output unit 70 Crystal oscillation circuit 100 Magnetic permeability sensor 101 Pattern coil 101a Reference point 102 Pattern resistor 102a Reference point 103 First capacitor 104 Second capacitor 105 Feedback resistor 106, 107 Unbuffered IC
DESCRIPTION OF SYMBOLS 108 Output terminal 200 Image forming apparatus 201 Paper feed tray 202 Paper feed roller 203 Registration roller 204 Paper 205 Conveying belt 206K, 206C, 206M, 206Y Image forming unit 207 Drive roller 208 Driven roller 209K, 209C, 209M, 209Y Photosensitive drum 210K , 210C, 210M, 210Y Charger 211 Optical writing device 212K, 212C, 212M, 212Y Developer 212a Sensor mounting surface 212b, 212c Conveying screw 212d, 212e, 212f, 212g Bearing 212h Sensor mounting surface 213K, 213C, 213M, 213Y Photosensitive Body cleaner 215K, 215C, 215M, 215Y transfer device 216 fixing device

JP 2010-26031 A

Claims (10)

An oscillation circuit detector that detects a physical quantity of a predetermined space based on the frequency of a signal output from an oscillation circuit,
A coil formed on a substrate by a plane pattern, the inductance of which changes due to a change in the physical quantity of the predetermined space;
Provided on the surface of the substrate opposite to the surface on which the coil is formed, and outputs a signal corresponding to a potential of a part of the capacitor and the resonance current loop that are connected to form a resonance current loop with the coil. An electrical component including an output terminal;
A pattern resistor connected in series to the resonant current loop and formed by a folded planar pattern on the same plane as the coil formed on the substrate;
Including
Of the angles formed by a straight line passing through the center of the coil and the center of the pattern resistance and a straight line passing through the coil or the center of the pattern resistance and a heat source that is a heat generation source, an acute angle is a predetermined angle. An oscillation circuit detector, wherein the coil forming surface is attached so as to face the predetermined space so as to be inside.   Of the coil and the pattern resistor, the formation area having the larger occupied area on the substrate is perpendicular to the line segment connecting the farthest point farthest from the heat source and the heat source, and the farthest point. The coil formation surface is arranged so that at least a part of the formation region of the coil and the pattern resistor having a smaller occupation area on the substrate is included on the heat source side than the straight line passing through the far point. The oscillation circuit detector according to claim 1, wherein the oscillation circuit detector is attached in a state of facing the predetermined space.   The formation surface of the coil faces the predetermined space so that all of the formation region of the coil and the pattern resistor that has a smaller occupied area on the substrate is included on the heat source side than the straight line. The oscillation circuit detector according to claim 2, wherein the oscillation circuit detector is attached in a state.   The coil and the pattern resistor are attached in a state where the formation surface of the coil is opposed to the predetermined space so that the line segment does not intersect the formation region having the smaller occupation area on the substrate. The oscillation circuit detector according to claim 2 or 3, characterized in that   The coil is attached in a state where the formation surface of the coil faces the predetermined space so that a difference between the distance from the coil to the heat source and a distance from the pattern resistor to the heat source is a predetermined value or less. The oscillation circuit detector according to any one of claims 1 to 4.   2. The coil is attached in a state in which a formation surface of the coil faces the predetermined space so that a distance from the coil to the heat source and a distance from the pattern resistor to the heat source coincide with each other. 5. The oscillation circuit detector according to claim 1.   The developer forming portion is mounted with the coil forming surface facing a developer containing portion containing a developer in which toner and magnetic particles for developing an electrostatic latent image are developed in the image forming apparatus. 7. The oscillation circuit detector according to claim 1, wherein the density of the toner in the developer in the section is detected. The developer storage unit includes a first developer transport unit and a second developer transport unit that transport the developer so that the developer spreads throughout the developer storage unit.
A developer delivery space that is a space in which the developer is delivered from the first developer transport unit to the second developer transport unit;
With
The first developer transporting portion rotates about a first rotation shaft supported by a first bearing fixed to the developer accommodating portion so as to face the developer delivery space, thereby The developer is conveyed by a screw provided around the first rotation shaft,
The second developer conveying portion rotates about a second rotation shaft supported by a second bearing fixed to the developer accommodating portion so as to face the developer delivery space, thereby Transporting the developer delivered from the first developer transport section by a screw provided around the second rotation shaft;
8. The apparatus according to claim 1, wherein the first bearing or the second bearing is used as a heat source, and the coil forming surface is attached to face the developer delivery space. 9. Oscillator circuit detector.   9. The oscillation circuit detector according to claim 1, wherein the coil forming surface is attached in a state of facing the predetermined space, and detects a temperature in the predetermined space. An oscillation circuit detector mounting method for detecting a physical quantity of a predetermined space based on the frequency of a signal output from an oscillation circuit,
A coil formed on a substrate by a plane pattern, the inductance of which changes due to a change in the physical quantity of the predetermined space;
Provided on the surface of the substrate opposite to the surface on which the coil is formed, and outputs a signal corresponding to a potential of a part of the capacitor and the resonance current loop that are connected to form a resonance current loop with the coil. An electrical component including an output terminal;
A pattern resistor connected in series to the resonant current loop and formed by a folded planar pattern on the same plane as the coil formed on the substrate;
Including
Of the angles formed by a straight line passing through the center of the coil and the center of the pattern resistance and a straight line passing through the coil or the center of the pattern resistance and a heat source that is a heat generation source, an acute angle is a predetermined angle. A method for mounting an oscillation circuit detector, wherein the coil forming surface is mounted facing the predetermined space so as to be inside.