JP2017203961A - Developing device and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device that can obtain a proper detection result upon detecting information pertaining to developer using sensors.SOLUTION: A developing device 40 comprises: a housing 41; a toner sensor 46; and a fixation part 60. The housing 41 is configured to store developer to be supplied to a photoreceptor drum 31, and the toner sensor 46 is configured to detect information pertaining to the developer fixed to an outside of the housing 41. The fixation part 60 is configured to fix the toner sensor 46 to the outside of the housing 41. The toner sensor 46 includes: a substrate 46a; and a coil 46b that serves as a detection unit provided in the substrate 46a. The fixation part 60 includes: a lock part 61 that brings an outer edge part of the substrate 46a into proximity to an outer face of the housing 41 to thereby lock the outer edge part of the substrate; and a protrusion part 62 that presses a portion on an inner side further than the outer edge part of the substrate 46a locked by the lock part 61 in a direction where the portion thereon is caused to separate from the outer face of the housing 41, and comes into contact with the portion thereon.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a developing device and an image forming apparatus including the developing device.

  In an electrophotographic image forming apparatus such as a copying machine or a printer, an apparatus that forms a toner image on paper by developing an electrostatic latent image formed on the surface of a photosensitive drum as an image carrier with a developing device is widely used. Has been. As a developing method, a two-component developing method using a developer containing toner and a magnetic carrier that is a carrier of the toner is known. In this case, since only the toner is consumed for development in the developing device, a developer detection sensor for preventing the toner from being insufficient is provided. Japanese Patent Application Laid-Open No. 2004-133867 discloses a conventional technique related to such a developing device.

  The conventional developing device described in Patent Document 1 includes a substrate on which a planar coil for toner concentration detection is provided, and a substrate mounting portion for arranging the substrate at a predetermined position. Further, the substrate has a position restricting portion that restricts the position in the left-right direction toward the developer conveying direction in order to dispose the planar coil at a predetermined position below the developer conveying member. Thus, the substrate on which the planar coil is provided can be easily installed at the accurate toner concentration detection position.

JP-A-11-249407

  However, the conventional developing device described in Patent Document 1 has a problem in that warpage of the substrate provided with the planar coil (detection unit) and rattling of the substrate in the substrate mounting portion may occur. Since the developer detection sensor has high sensitivity related to the distance from the developer, and variations in the distance greatly affect the detection accuracy, it is important to keep the distance from the developer constant. In the developing device described in Patent Document 1, there is a possibility that the distance between the developer and the planar coil (detection unit) varies due to warpage or rattling of the substrate, and an appropriate detection result cannot be obtained. There was concern.

  The present invention has been made in view of the above points, and provides a developing device and an image forming apparatus capable of obtaining an appropriate detection result when detecting information relating to a developer using a sensor. Objective.

  In order to solve the above-described problems, the developing device of the present invention includes a container, a developing member, a stirring chamber, a developer detection sensor, and a fixing unit. The storage container stores a developer to be supplied to the image carrier. The developing member is disposed in an opening provided in the container so as to face the image carrier. The stirring chamber is provided inside the container and transports the developer while stirring. The developer detection sensor is fixed outside the container and detects information related to the developer inside the stirring chamber. The fixing unit fixes the developer detection sensor to the outside of the container. The developer detection sensor includes a substrate and a detection unit provided on the substrate. The fixing portion separates the locking portion that locks the outer edge portion of the substrate close to the outer surface of the storage container, and the portion inside the outer edge portion of the substrate locked by the locking portion from the outer surface of the storage container. And a projecting portion that presses in the direction and contacts.

  According to the configuration of the present invention, the substrate on which the detection unit of the developer detection sensor is provided is fixed to the container of the developing device in a warped form in advance. Thereby, the distance between the detection part of the sensor and the developer can be kept constant. Therefore, it is possible to obtain an appropriate detection result when detecting information related to the developer using the developer detection sensor in the developing device.

1 is a front view of an image forming apparatus according to a first embodiment of the present invention. 1 is a block diagram illustrating a configuration of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a vertical sectional front view of the developing device of the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a vertical sectional view of the toner sensor and its fixing part of the developing device according to the first embodiment of the present invention. FIG. 2 is a plan view of a toner sensor and a fixing portion thereof in the developing device according to the first embodiment of the present invention. FIG. 6 is an exploded perspective view of a toner sensor and a fixing portion thereof in a developing device according to a second embodiment of the present invention. FIG. 6 is a vertical sectional view of a toner sensor and a fixing portion thereof in a developing device according to a second embodiment of the present invention. FIG. 10 is an exploded perspective view of a toner sensor and a fixing part thereof of a developing device according to a third embodiment of the present invention. FIG. 10 is an external perspective view of a toner sensor and a fixing part thereof of a developing device according to a third embodiment of the present invention. FIG. 10 is a vertical sectional view of a toner sensor and a fixing portion thereof in a developing device according to a third embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following contents.

<First Embodiment>
First, the structure of the image forming apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is an example of a front view of the image forming apparatus, and FIG. 2 is a block diagram illustrating a configuration of the image forming apparatus. This image forming apparatus is a so-called multifunction machine having a plurality of functions such as copying (printing), scanning (image reading), and facsimile.

  As shown in FIG. 1, the image forming apparatus 1 has a document transport unit 3 placed on the upper surface of a main body 2, and includes a document image reading unit 4 inside the main body 2 below it. When a user causes the image forming apparatus 1 to execute an image reading job, a document on which an image such as a character, graphic, or pattern is drawn is stacked on the document transport unit 3 or the document is not displayed on the upper surface of the document image reading unit 4. Or placed on the contact glass shown. A main control unit 20 (see FIG. 2), which will be described later, gives an operation instruction to the document conveying unit 3 and the image reading unit 4 to read an image drawn on the document. The read image data is stored in the storage unit 23 (see FIG. 2), for example.

  An operation panel 5 is provided above the image forming apparatus 1 and on the front side of the image reading unit 4. The operation panel 5 includes a display unit 5w. The operation panel 5 accepts a command or the like for causing the image forming apparatus 1 to execute a copy (print) job, a scan (image reading) job, and a facsimile transmission job by the user. The operation panel 5 accepts settings such as printing conditions such as the type and size of paper used for printing, enlargement / reduction, and the presence / absence of double-sided printing, and accepts input of settings such as a fax number and a sender name in facsimile transmission. To do. Furthermore, the operation panel 5 also serves as a notifying unit for notifying the user of the state, cautions, error message, and the like on the display unit 5w, for example. The input information received by the operation panel 5 is transmitted to the main control unit 20.

  The image forming apparatus 1 includes a printing unit 6 for executing a print job in a portion below the image reading unit 4 of the main body 2. The printing unit 6 includes a paper feed unit 7, a paper transport unit 8, an exposure unit 9, an image forming unit 30, a transfer unit 11, and a fixing unit 12.

  The paper feed unit 7 stores a plurality of sheets P and sends out the sheets P one by one at the time of printing. The paper transport unit 8 transports the paper P sent from the paper feed unit 7 and discharges the fixed paper P to the paper discharge unit 13 of the apparatus. The exposure unit 9 irradiates the image forming unit 30 with laser light controlled based on the image data. The image forming unit 30 forms an electrostatic latent image of the original image on the surface of the photosensitive drum 31 by the laser light emitted from the exposure unit 9, and the developing device 40 attaches toner to the electrostatic latent image and develops it. To form a toner image. The transfer unit 11 transfers the toner image on the surface of the photosensitive drum 31 formed by the image forming unit 30 to the paper P. The fixing unit 12 heats and presses the paper P on which the toner image is transferred to fix the toner image on the paper P. The main control unit 20 controls such printing operation of the printing unit 6.

  The image forming apparatus 1 includes a communication unit 14 for performing communication such as facsimile transmission / reception and data transmission / reception with an external communication apparatus or a computer. The communication unit 14 is connected to a telephone line, and exchanges image data and the like with an external communication device by facsimile communication using the telephone line. The communication unit 14 is connected to a network line, and exchanges image data and the like with an external computer by network communication using the network line. The main control unit 20 causes the communication unit 14 to execute transmission and reception of data to an external communication device or the like.

  The image forming apparatus 1 includes a main control unit 20 shown in FIG. 2 for operation control of the entire apparatus. The main control unit 20 includes a CPU 21, an image processing unit 22, and other electronic circuits and electronic components (not shown). The main control unit 20 uses a central processing unit (CPU) 21 and an image processing unit 22 to control each component of the image forming apparatus 1 based on a program and data stored in and input to the storage unit 23 and a series of operations. An image forming operation is realized. In the printing unit 6, the sheet feeding unit 7, the sheet transport unit 8, the exposure unit 9, the image forming unit 30, the transfer unit 11, and the fixing unit 12, which are constituent elements, individually receive commands from the main control unit 20. The components are linked to execute printing on the paper P.

  Next, the configuration of the developing device 40 of the image forming unit 30 will be described with reference to FIG. FIG. 3 is a vertical sectional front view of the developing device 40.

  As shown in FIG. 3, the developing device 40 includes a housing 41, a first stirring screw 42, a second stirring screw 43, a developing roller 44, a regulating blade 45, and a toner sensor 46 that is a developer detection sensor.

  The housing 41 is a storage container for storing a two-component developer composed of toner and a magnetic carrier as a developer to be supplied to the photosensitive drum 31 as an image carrier. The housing 41 has an elongated shape in the axial direction of the photosensitive drum 31 and is disposed with its longitudinal direction horizontal. The housing 41 includes a first stirring chamber 48 and a second stirring chamber 49 that are partitioned by a partition wall 47. The second stirring chamber 49 is disposed adjacent to the region where the developing roller 44 is disposed. The first stirring chamber 48 is disposed in a region separated from the developing roller 44 with the second stirring chamber 49 therebetween. The first stirring chamber 48 includes a developer supply port (not shown), and the developer is supplied from the outside.

  The first stirring screw 42 is disposed in the first stirring chamber 48. The first stirring screw 42 has a configuration in which a spiral blade 42b is provided around a support shaft 42a, and is supported by the housing 41 so as to be rotatable about an axis extending in the horizontal direction. The first stirring screw 42 rotates counterclockwise in FIG. 3 to stir and convey the developer. The developer supplied to the first stirring chamber 48 from the outside is guided to the second stirring chamber 49 by the rotation of the first stirring screw 42.

  The second stirring screw 43 is disposed in the second stirring chamber 49. The second stirring screw 43 has a configuration in which a spiral blade 43b is provided around a support shaft 43a, and is supported by the housing 41 so as to be rotatable about an axis extending in the horizontal direction. The second stirring screw 43 rotates counterclockwise in FIG. 3 to stir and convey the developer. The developer guided from the first stirring chamber 48 to the second stirring chamber 49 by the rotation of the second stirring screw 43 is supplied to the developing roller 44.

  The developing roller 44 is a developing member disposed in a region on the photosensitive drum 31 side of the second stirring chamber 49. The housing 41 includes an opening 50 at a location adjacent to the photosensitive drum 31. The developing roller 44 is supported by the housing 41 so as to be rotatable about an axis extending in the horizontal direction at the opening 50. A part of the circumferential surface of the developing roller 44 is located inside the housing 41, and another part of the circumferential surface is exposed to the outside from the opening 50 and faces the photosensitive drum 31.

  The developing roller 44 is configured by a magnet roller having a magnetic field generating member (not shown) made of a permanent magnet fixed on the inner surface thereof, for example. A toner thin layer is formed by attaching (carrying) toner onto the surface of the developing roller 44 by the magnetic force of the magnetic field generating member.

  The developing roller 44, the first stirring screw 42, and the second stirring screw 43 are parallel to each other and rotatably supported by the housing 41. The developing roller 44, the first stirring screw 42, and the second stirring screw 43 are rotationally driven by a motor (not shown).

  The regulating blade 45 is provided in the opening 50 so as to be close to the developing roller 44 and to have its tip opposed to the surface of the developing roller 44. The regulating blade 45 is disposed with a predetermined gap between the tip thereof and the surface of the developing roller 44, and regulates the amount of toner supplied to the photosensitive drum 31.

  The regulation blade 45 is made of a magnetic stainless steel such as SUS430. Then, a magnetic field is generated between the developing roller 44 and the regulating blade 45 by a magnetic field generating member of the developing roller 44 provided to face the tip of the regulating blade 45. Thereby, not only the distance between the regulating blade 45 and the developing roller 44 but also the amount of toner adhering to the developing roller 44 is strictly regulated not only by the strength of the magnetic field. Therefore, it is possible to form a toner thin layer of several tens of microns.

  The toner sensor 46 is fixed outside the bottom surface of the housing 41. The toner sensor 46 may be fixed to the outside of the side surface or the upper surface of the housing 41. The toner sensor 46 is a developer detection sensor that detects information related to the developer inside the stirring chamber. That is, the toner sensor 46 is a magnetic permeability detection type toner concentration detection sensor that detects a change in magnetic permeability and obtains a ratio between the toner and the magnetic carrier. If the ratio of the developer toner and the magnetic carrier in the stirring chamber changes, the magnetic permeability also changes, and the output signal of the toner sensor 46 changes accordingly. Based on the sensor output signal received from the toner sensor 46, the main control unit 20 controls the start and stop of supply of the developer to the developing device 40.

  Next, the configuration of the toner sensor 46 and the configuration related to the fixing to the housing 41 will be described in detail with reference to FIGS. 4 and 5. 4 and 5 are a vertical sectional view and a plan view of the toner sensor 46 of the developing device 40 and its fixing portion. In FIG. 4, the upper side of the housing 41 shows the inside of the housing 41, and the lower side of the housing 41 shows the outside of the housing 41.

  The toner sensor 46 includes a substrate 46a, a coil 46b, a circuit part 46c, and a connector part 46d as shown in FIGS.

  The substrate 46a is made of, for example, glass epoxy and has a rectangular shape in plan view. The substrate 46a is formed, for example, in a size having a long side of about 30 mm to 50 mm, a short side of about 20 mm to 30 mm, and a thickness of about 1 mm to 1.6 mm.

  The coil 46b is a detection unit composed of a spiral planar coil formed on the surface (main surface) of the substrate 46a by the wiring pattern of the substrate 46a. For example, the coil 46b has a spiral portion with a diameter of 10 mm to 15 mm, and is arranged such that the central axis of the spiral portion extends in parallel with the normal direction of the surface (main surface) of the substrate 46a. The coil 46b is provided on one surface of the substrate 46a, but may be provided on both surfaces or in the inner layer of the substrate 46a.

  The circuit unit 46c constitutes a circuit for obtaining a detection signal by the coil 46b, and is electrically connected to the coil 46b. The circuit unit 46c includes an application circuit that applies a pulse signal to the coil 46b, and a signal processing circuit that processes an output signal from the coil 46b to generate an output corresponding to the magnetic permeability. Note that the circuit unit 46c including these circuits may be provided outside the substrate 46a, and only the coil 46b may be provided on the substrate 46a. Further, a connector portion 46d for obtaining electric power from the outside is electrically connected to the circuit portion 46c.

  A fixing portion 60 for fixing the toner sensor 46 to the outside of the housing 41 is provided on the bottom surface of the housing 41. The fixing part 60 includes a locking part 61 and a protruding part 62.

  The locking portion 61 includes locking pieces 61A and 61B provided at three locations corresponding to the periphery of the outer edge portion of the substrate 46a. The three locking pieces 61 </ b> A and 61 </ b> B are provided around the protrusion 62. The two locking pieces 61A are arranged outside the two long sides of the substrate 46a so as to face each other with the substrate 46a interposed therebetween. One locking piece 61B is disposed outside one short side of the substrate 46a. With respect to the longitudinal direction of the substrate 46 a, the two locking pieces 61 </ b> A and the one locking piece 61 </ b> B are positioned on opposite sides of the arrangement area of the protrusion 62.

  The locking pieces 61A and 61B protrude outward from the outer surface of the housing 41, and have a hook shape with the tip facing the direction in which the substrate 46a exists. The substrate 46a is locked between the hook-shaped portion at the tip of the locking pieces 61A and 61B and the outer surface of the housing 41.

  The protrusion 62 is provided at one location corresponding to a location inside the outer edge of the substrate 46a. The protrusion 62 is disposed at a location corresponding to the center of the spiral of the coil 46b. The protruding portion 62 protrudes outward from the outer surface of the housing 41 with a protruding length of, for example, about 0.5 mm.

  Regarding the direction from the outer surface of the housing 41 to the outside (the downward direction in FIG. 4), the distance between the tip of the projection 62 and the tips of the locking pieces 61A and 61B is shorter than the thickness of the substrate 46a. The tip of the part 62 may be further away from the outer surface of the housing 41 than the tip of the locking part 61.

  With respect to the fixing portion 60 having such a configuration, the toner sensor 46 has a relationship between the tip of the protruding portion 62 and the engaging portion 61 in the direction in which the substrate 46a faces outward from the outer surface of the housing 41 (downward in FIG. 4). It installs so that it may be pinched | interposed between the front-end | tip of stop piece 61A, 61B. At this time, the locking portion 61 locks the outer edge portion of the substrate 46 a close to the outer surface of the housing 41. Further, the projecting portion 62 is pressed and contacted in a direction in which a portion inside the outer edge portion of the substrate 46 a locked to the locking portion 61 is separated from the outer surface of the housing 41.

  As a result, the toner sensor 46 is fixed to the outer surface of the housing 41 such that the substrate 46a is warped in advance by elastic deformation. Since the warping restoring force (elastic force) acting on the substrate 46a is used to restrain it by the locking portion 61 and the protrusion 62, the substrate 46a is not displaced, and the coil 46b of the toner sensor 46, the developer T, and the like. Is kept constant.

  In addition, it is preferable that the protrusion length of the protrusion 62 is longer than the maximum value of the warpage amount of the substrate 46a derived from the size of the substrate 46a.

Second Embodiment
Next, a developing device according to a second embodiment of the present invention will be described with reference to FIGS. 6 and 7 are an exploded perspective view and a vertical sectional view of the toner sensor of the developing device and its fixing part. Since the basic configuration of this embodiment is the same as that of the first embodiment described above, the same components as in the first embodiment are assigned the same names and reference numerals as before, and the description thereof is omitted. May be omitted. FIG. 7 shows the inside of the housing 41 above the housing 41 and shows the outside of the housing 41 below the housing 41.

  In the developing device 40 according to the second embodiment, the fixing portion 60 includes the welding pins 61C and 61D and the notches 61E and 61F shown in FIGS.

  The welding pins 61C and 61D are provided at three locations corresponding to the outer edge portion of the substrate 46a around the protruding portion 62. With respect to the longitudinal direction of the substrate 46 a, the two welding pins 61 </ b> C and the one welding pin 61 </ b> D are located on the opposite sides with respect to the arrangement region of the protrusions 62. In a state before the substrate 46a is fixed, the welding pins 61C and 61D form a column shape protruding outward from the outer surface of the housing 41.

  The notches 61E and 61F are provided at three locations around the coil 46b corresponding to the locations of the welding pins 61C and 61D on the outer edge of the substrate 46a. With respect to the longitudinal direction of the substrate 46a, the two cutout portions 61E and the one cutout portion 61F are located on opposite sides of the arrangement region of the coil 46b. The notches 61E and 61F have a concave shape that is recessed from the outer edge of the substrate 46a toward the inside of the substrate 46a.

  When fixing the toner sensor 46 to the fixing portion 60, first, the toner sensor 46 is fixed so that the three welding pins 61C and 61D of the fixing portion 60 are inserted into the three notches 61E and 61F of the toner sensor 46. It arranges in part 60. Subsequently, the tip side of the welding pins 61C and 61D is heated and melted. The welding pins 61C and 61D have a mushroom-like shape like the head of a rivet shown in FIG. 7 at their distal ends, and are fixed so that the substrate 46a does not come off.

  At this time, the welding pins 61 </ b> C and 61 </ b> D of the locking portion 61 lock the outer edge portion of the substrate 46 a close to the outer surface of the housing 41. Further, the projecting portion 62 is pressed and contacted in a direction in which a portion inside the outer edge portion of the substrate 46 a locked to the locking portion 61 is separated from the outer surface of the housing 41. As a result, the toner sensor 46 is fixed to the outer surface of the housing 41 such that the substrate 46a is warped in advance by elastic deformation.

<Third Embodiment>
Next, a developing device according to a third embodiment of the present invention will be described with reference to FIGS. 8, 9, and 10 are an exploded perspective view, an external perspective view, and a vertical sectional view of the toner sensor and its fixing portion of the developing device. Since the basic configuration of this embodiment is the same as that of the first and second embodiments described above, the same elements as those in the previous embodiment are denoted by the same names and the same reference numerals. The description may be omitted. FIG. 10 shows the inside of the housing 41 above the housing 41 and shows the outside of the housing 41 below the housing 41.

  In the developing device 40 according to the third embodiment, the fixing portion 60 includes a welding pin 61C, a notch portion 61E, and a leaf spring 61G as an elastic member as shown in FIGS.

  The welding pins 61C are provided at two locations corresponding to the outer edge portion of the substrate 46a. The two welding pins 61C are arranged on the outside of the two long sides of the substrate 46a so as to face each other with the substrate 46a interposed therebetween.

  The notches 61E are provided at two locations corresponding to the locations of the welding pins 61C on the outer edge of the substrate 46a. The two notches 61E are arranged side by side in the short side direction on the outer edges of the two long sides of the substrate 46a.

  The leaf spring 61G is disposed outside one short side of the substrate 46a. With respect to the longitudinal direction of the substrate 46a, the leaf spring 61G, the two welding pins 61C, and the cutout portion 61E are located on opposite sides of the arrangement region of the protrusion 62 and the coil 46b.

  The plate spring 61G includes a spring portion 61H that engages with one short side portion of the substrate 46a from the outside in the longitudinal direction of the substrate 46a. The tip of the spring portion 61H engages with the surface (main surface) of the substrate 46a opposite to the surface facing the outer surface of the housing 41. In the plate spring 61G, the support portion 61K of the spring portion 61H is fixed to the outer surface of the housing 41 using a welding pin 61M. The leaf spring 61 </ b> G has an elastic force that biases the spring portion 61 </ b> H in a direction in which one short side portion of the substrate 46 a approaches the outer surface of the housing 41. Note that another elastic member may be used instead of the leaf spring 61G.

  When fixing the toner sensor 46 to the fixing portion 60, first, the nurse sensor 46 is arranged on the fixing portion 60 so that the two notches 61E of the toner sensor 46 are inserted into the two welding pins 61C of the fixing portion 60. To do. Subsequently, the tip side of the welding pin 61C is heated and melted. Then, the spring portion 61H is engaged with the surface of one short side portion of the substrate 46a, and the leaf spring 61G is fixed to the outer surface of the housing 41 against the elastic force of the spring portion 61H.

  At this time, the welding pins 61 </ b> C and the leaf springs 61 </ b> G of the locking portion 61 lock the outer edge portion of the substrate 46 a close to the outer surface of the housing 41. Further, the projecting portion 62 is pressed and contacted in a direction in which a portion inside the outer edge portion of the substrate 46 a locked to the locking portion 61 is separated from the outer surface of the housing 41. As a result, the toner sensor 46 is fixed to the outer surface of the housing 41 such that the substrate 46a is warped in advance by elastic deformation.

  As in the first, second, and third embodiments, the developing device 40 of the image forming apparatus 1 includes a housing 41 that is a container, a developing roller 44 that is a developing member, a first stirring chamber 48, and a second stirring chamber. 49, a toner sensor 46, which is a developer detection sensor, and a fixing unit 60. The housing 41 stores a developer to be supplied to the photosensitive drum 31. The developing roller 44 is disposed in the opening 50 provided in the housing 41 so as to face the photosensitive drum 31. The stirring chamber is provided inside the housing 41 and conveys the developer while stirring. The toner sensor 46 is fixed to the outside of the housing 41 and detects information relating to the developer inside the second stirring chamber 49. The fixing unit 60 fixes the toner sensor 46 to the outside of the housing 41. The toner sensor 46 includes a substrate 46a and a coil 46b which is a detection unit provided on the substrate 46a. The fixing portion 60 holds the outer edge portion of the substrate 46 a close to the outer surface of the housing 41, and the housing 41 is located inside the outer edge portion of the substrate 46 a locked to the locking portion 61. And a protrusion 62 that comes into contact with pressure in a direction away from the outer surface.

  According to this configuration, the fixing unit 60 can fix the toner sensor 46 to the outer surface of the housing 41 such that the substrate 46a is warped in advance by elastic deformation. Since the restraining portion 61 and the protruding portion 62 restrain the warp restoring force (elastic force) acting on the substrate 46a, the displacement of the substrate 46a can be suppressed. Thereby, the distance between the coil 46b of the toner sensor 46 and the developer T can be kept constant. Accordingly, when the toner sensor 46 is used in the developing device 40 to obtain the ratio between the toner of the developer T and the magnetic carrier, an appropriate detection result can be obtained.

  Strictly speaking, if the distance between the coil 46b of the toner sensor 46 and the developer T can be kept constant, it corresponds to the actual ratio between the toner of the developer T and the magnetic carrier in the developing device 40. The toner sensor 46 outputs a detection signal. If data in which the output value of the toner sensor 46 is associated with the ratio between the toner and the magnetic carrier is prepared in advance, the developer T is supplied to the developing device 40 so that the ratio becomes an appropriate ratio. It is possible.

  And the protrusion part 62 is arrange | positioned in the location corresponding to the coil 46b.

  According to this configuration, the distance between the coil 46b and the developer T can be set to any desired distance by adjusting the protruding length of the protrusion 62 from the outer surface of the housing 41. Therefore, the detection accuracy of the toner sensor 46 can be improved.

  Further, the locking portions 61 are provided at three locations around the protruding portion 62.

  According to this configuration, it is possible to cause a suitable warp to the substrate 46a with the position of the protrusion 62 as a substantial center. Thus, the toner sensor 46 can be fixed to the outer surface of the housing 41 using the locking portion 61 and the protruding portion 62, and the fixed state can be maintained.

  Moreover, in 3rd Embodiment, the fixing | fixed part 60 contains the leaf | plate spring 61G which is an elastic member.

  According to this configuration, the leaf spring 61 </ b> G can be used for one locking portion 61 among the three locking portions 61 around the protrusion 62. Accordingly, even when the elastic deformation of the substrate 46a approaches plastic deformation due to secular change or the like, it is possible to cause a suitable warp to the substrate 46a using the elastic force of the leaf spring 61G. Therefore, the distance between the coil 46b of the toner sensor 46 and the developer T can be maintained constant over a long period of time.

  Further, in the embodiment, the developing device 40 having the above configuration is provided in the image forming apparatus 1.

  According to this configuration, in the image forming apparatus 1, it is possible to obtain an appropriate detection result when the toner sensor 46 is used to obtain the ratio of the developer toner to the magnetic carrier.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, the locking piece, the welding pin, and the elastic member used as the locking portion 61 in the first, second, and third embodiments may be used in appropriate combination.

  The present invention can be used in a developing device and an image forming apparatus.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 30 Image forming part 31 Photosensitive drum (image carrier)
40 Developing device 41 Housing (container)
44 Developing roller (developing member)
46 Toner sensor (Developer detection sensor)
46a Substrate 46b Coil (detector)
48 1st stirring chamber 49 2nd stirring chamber 60 Fixed part 61 Locking part 61G Leaf spring (elastic member)
62 Projection

Claims (5)

A storage container for storing a developer to be supplied to the image carrier;
A developing member disposed opposite to the image carrier in an opening provided in the container;
A stirring chamber provided inside the storage container for transporting the developer while stirring;
A developer detection sensor that is fixed to the outside of the container and detects information related to the developer inside the stirring chamber;
A fixing portion for fixing the developer detection sensor to the outside of the container;
With
The developer detection sensor includes a substrate, and a detection unit provided on the substrate,
The fixing portion holds the outer edge portion of the substrate close to the outer surface of the storage container, and the inner portion of the substrate that is locked by the locking portion is stored in the holding portion. And a protrusion that presses and contacts in a direction away from the outer surface of the container.   The developing device according to claim 1, wherein the protrusion is disposed at a position corresponding to the detection unit.   The developing device according to claim 1, wherein the locking portion is provided at three locations around the protrusion.   The developing device according to claim 1, wherein the fixing portion includes an elastic member.   An image forming apparatus comprising the developing device according to claim 1.

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