Image forming apparatus

Abstract

To provide an image forming apparatus that has improved the accuracy of detection with a light emitting section and a light receiving section.SOLUTION: An image forming apparatus forms a toner image formed on an image carrier on a sheet, and the image forming apparatus comprises: an apparatus main body; and a process unit that has a frame body that constitutes a storage section storing developer, a developer carrier that supplies developer to an electrostatic latent image formed on the image carrier to develop the electrostatic latent image, and a substrate that is attached to the frame body, the process unit attached to the apparatus main body. The substrate has a light emitting section that emits light, and a light receiving section that receives the light emitted from the light emitting section and having passed through the inside of the storage section.SELECTED DRAWING: Figure 15

Description

Technical Field

[0001] The present invention relates to an image forming apparatus that forms an image on a recording material.

Background Art

[0002] Generally, an electrophotographic image forming apparatus forms an image by transferring a toner image formed on the surface of a photosensitive drum to a transfer material as a transfer medium. And, as a toner supply method, for example, there is known a process cartridge method in which a photosensitive drum and a developing container are integrated as a process cartridge, and when the toner runs out, the process cartridge is replaced with a new one.

[0003] Conventionally, a toner remaining amount detection device for detecting the remaining amount of toner in a toner cartridge that stores toner has been proposed (see Patent Document 1). This toner remaining amount detection device provides transparent windows on two opposing wall surfaces of the toner cartridge, and sets the optical path between a light emitting portion and a light receiving portion so as to pass through these transparent windows. The optical path crossing the inside of the toner cartridge is transmitted or blocked according to the remaining amount of toner, and the remaining amount of toner in the toner cartridge can be detected by measuring the transmission time of the optical path.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, in a process cartridge type image forming apparatus, there is a small gap between the image forming apparatus body and the process cartridge so that the process cartridge can be attached to and detached from the image forming apparatus body. For this reason, when the light-emitting unit and light-receiving unit described in Patent Document 1 are installed in the image forming apparatus body, there is a risk that the process cartridge and the light-emitting unit and light-receiving unit may become misaligned, which could reduce the accuracy of toner level detection.

[0006] Therefore, the present invention aims to provide an image forming apparatus that improves the detection accuracy of the light-emitting unit and the light-receiving unit. [Means for solving the problem]

[0007] The present invention relates to an image forming apparatus, It has a control unit. The apparatus comprises a main body, a process unit attached to the main body, a roller, a frame comprising a housing for containing a developer to be carried on the roller, and the direction of the rotation axis of the roller being the longitudinal direction, Electrical circuit board electrically connected to the control unit. A process unit comprising, The electrical substrate is provided with a light-emitting element that emits light and a light-receiving element that receives light emitted from the light-emitting element and that has passed through the inside of the housing, and the electrical substrate It is characterized in that it is supported in the central part of the frame in the longitudinal direction. [Effects of the Invention]

[0008] According to the present invention, an image forming apparatus can be provided that improves the detection accuracy of the light-emitting unit and the light-receiving unit. [Brief explanation of the drawing]

[0009] [Figure 1] (a) is a cross-sectional view showing an image forming apparatus according to the first embodiment, and (b) is a perspective view showing an image forming apparatus. [Figure 2] (a) is a cross-sectional view showing the image forming apparatus, and (b) is a perspective view showing the image forming apparatus with the top cover open. [Figure 3] A cross-sectional view showing an image forming apparatus with the process unit removed. [Figure 4](a) is a perspective view showing the image forming apparatus with the pressure plate of the reading device closed, (b) is a perspective view showing the image forming apparatus with the pressure plate open, and (c) is a perspective view showing the image forming apparatus with the reading device open. [Figure 5] (a) is a perspective view showing the developing container and toner pack, and (b) is a front view showing the developing container and toner pack. [Figure 6] (a) is a cross-sectional view of 6A-6A in Figure 5(b), and (b) is a cross-sectional view of 6B-6B in Figure 5(b). [Figure 7] A perspective view showing a toner pack. [Figure 8] (a) is a front view showing the toner pack, (b) is a front view showing a first modified example of the toner pack, and (c) is a front view showing a second modified example of the toner pack. [Figure 9] (a) is a cross-sectional view showing the toner level sensor, and (b) is a cross-sectional view of (a) between 9B and 9B. [Figure 10] A circuit diagram showing the toner level sensor. [Figure 11] (a) is a cross-sectional view showing the developing container with a low toner level, and (b) is a cross-sectional view showing the developing container with a high toner level. [Figure 12] A block diagram showing the control system of an image forming apparatus. [Figure 13] (a) is a perspective view showing the toner level panel 400 at the NearOut level, (b) is a perspective view showing the toner level panel 400 at the Low level, (c) is a perspective view showing the toner level panel 400 at the Mid level, and (d) is a perspective view showing the toner level panel 400 at the Full level. [Figure 14] A perspective view showing a developing apparatus. [Figure 15] (a) is a perspective view showing the substrate and substrate holder assembled to the developing container lid, (b) is a perspective view showing the substrate and substrate holder, and (c) is another perspective view showing the substrate and substrate holder. [Figure 16] (a) is a cross-sectional view of the developing apparatus, and (b) is a cross-sectional view of (a) between 16B and 16B. [Figure 17](a) shows a cross-sectional view of the developing container with a small toner remaining amount, and (b) shows a cross-sectional view of the developing container with a large toner remaining amount.

Embodiment for Implementing the Invention

[0010] Hereinafter, exemplary embodiments for implementing the present invention will be described while referring to the drawings.

[0011] <First Embodiment> FIG. 1(a) is a schematic diagram showing the configuration of an image forming apparatus 1 according to the first embodiment. The image forming apparatus 1 is a monochrome printer that forms an image on a recording material based on image information input from an external device. The recording material includes various sheet materials of different materials, such as paper like plain paper and cardboard, plastic films like overhead projector sheets, special-shaped sheets like envelopes and index papers, and cloth.

[0012] [Overall Configuration] As shown in FIGS. 1(a) and (b), the image forming apparatus 1 includes a printer main body 100 as the apparatus main body, a reading device 200 that is supported by the printer main body 100 so as to be openable and closable, and an operation unit 300 attached to the exterior surface of the printer main body 100. The printer main body 100 includes an image forming unit 10 that forms a toner image on the recording material, a feeding unit 60 that feeds the recording material to the image forming unit 10, a fixing unit 70 that fixes the toner image formed by the image forming unit 10 to the recording material, and a discharge roller pair 80.

[0013] The image forming unit 10 includes a scanner unit 11, an electrophotographic process unit 20, and a transfer roller 12 that transfers a toner image, which is a developer image formed on the photosensitive drum 21 of the process unit 20, to a recording material. As shown in Figures 6(a) and 6(b), the process unit 20 includes a photosensitive drum 21, a developing device 30 which includes a charging roller 22, a pre-exposure device 23, and a developing roller 31 arranged around the photosensitive drum 21. The process unit 20 is detachably attached to the printer body 100 (see Figure 3). The process unit 20 may also be screwed to the printer body 100, and may be removed mainly by a service technician rather than a user. On the other hand, the process unit 20 does not include structural members of the printer body 100, such as the housing frame of the printer body 100.

[0014] The photosensitive drum 21 is a photoreceptor molded into a cylindrical shape. In this embodiment, the photosensitive drum 21 has a photosensitive layer formed of a negatively charged organic photoreceptor on a drum-shaped substrate made of aluminum. The photosensitive drum 21, as an image carrier, is rotated by a motor in a predetermined direction (clockwise in the figure) at a predetermined process speed.

[0015] The charging roller 22 contacts the photosensitive drum 21 with a predetermined pressure, forming a charged area. Furthermore, by applying a desired charging voltage from a high-voltage charging power supply, the surface of the photosensitive drum 21 is uniformly charged to a predetermined potential. In this embodiment, the photosensitive drum 21 is negatively charged by the charging roller 22. The pre-exposure device 23 discharges the surface potential of the photosensitive drum 21 before it enters the charged area in order to generate a stable discharge in the charged area.

[0016] The scanner unit 11, acting as an exposure means, scans and exposes the surface of the photosensitive drum 21 by irradiating it with laser light corresponding to image information input from an external device or reading device 200 using a polygon mirror. This exposure forms an electrostatic latent image on the surface of the photosensitive drum 21 corresponding to the image information. The scanner unit 11 is not limited to a laser scanner device; for example, an LED exposure device having an LED array in which multiple LEDs are arranged along the longitudinal direction of the photosensitive drum 21 may be used.

[0017] The developing device 30 includes a developing roller 31 as a developer carrier for holding the developer, a developing container 32 as the frame of the developing device 30, and a supply roller 33 capable of supplying developer to the developing roller 31. The developing roller 31 and the supply roller 33 are rotatably supported by the developing container 32. The developing roller 31 is positioned at the opening of the developing container 32 so as to face the photosensitive drum 21. The supply roller 33 is in rotatable contact with the developing roller 31, and the toner, which is the developer contained in the developing container 32, is applied to the surface of the developing roller 31 by the supply roller 33. Note that the supply roller 33 is not necessarily required if a configuration is in place that can supply sufficient toner to the developing roller 31.

[0018] The developing apparatus 30 of this embodiment uses a contact developing method. That is, the toner layer supported on the developing roller 31 comes into contact with the photosensitive drum 21 in the developing section (developing region) where the photosensitive drum 21 and the developing roller 31 face each other. A developing voltage is applied to the developing roller 31 by a high-voltage developing power supply. Under the developing voltage, the toner supported on the developing roller 31 is transferred from the developing roller 31 to the drum surface according to the potential distribution on the surface of the photosensitive drum 21, thereby developing an electrostatic latent image into a toner image. In this embodiment, an inversion developing method is employed. That is, after being charged in the charging process, the toner adheres to the surface region of the photosensitive drum 21, where the amount of charge has decreased due to exposure in the exposure process, thereby forming a toner image.

[0019] Furthermore, this embodiment uses a toner with a particle size of 6 μm and a normal charge polarity of negative polarity. As an example, the toner used in this embodiment is a polymerized toner produced by a polymerization method. In addition, the toner in this embodiment does not contain magnetic components and is a so-called non-magnetic one-component developer in which the toner is supported on the developing roller 31 mainly by intermolecular forces and electrostatic forces (mirror image forces). However, a one-component developer containing magnetic components may also be used. Furthermore, the one-component developer may contain additives (for example, wax or silica fine particles) to adjust the fluidity and charge performance of the toner in addition to the toner particles. Alternatively, a two-component developer composed of a non-magnetic toner and a magnetic carrier may be used as the developer. When a magnetic developer is used, for example, a cylindrical developing sleeve with a magnet placed inside may be used as the developer carrier.

[0020] An agitator 34 is provided inside the developing container 32. Driven by a motor M1 (see Figure 12), the agitator 34 rotates to agitate the toner inside the developing container 32 and to transport the toner toward the developing roller 31 and the supply roller 33. The agitator 34 also circulates the toner that is not used for developing and has been stripped from the developing roller 31 within the developing container, thereby homogenizing the toner inside the developing container. The agitator 34 is not limited to a rotating form. For example, an oscillating agitator may be used. In addition, another agitator may be provided in addition to the agitator 34.

[0021] Furthermore, a developing blade 35 is positioned at the opening of the developing container 32 where the developing roller 31 is located, to regulate the amount of toner carried on the developing roller 31. The toner supplied to the surface of the developing roller 31 passes through the area opposite the developing blade 35 as the developing roller 31 rotates, resulting in a uniformly thin layer and negative charge due to triboelectricity.

[0022] As shown in Figures 1(a) and 1(b), the feeding unit 60 includes a front door 61 that is openably and closably supported by the printer body 100, a tray section 62, a middle plate 63, a tray spring 64, and a pickup roller 65. The tray section 62 forms the bottom surface of the recording material storage space that is revealed when the front door 61 is opened, and the middle plate 63 is supported by the tray section 62 so as to be able to move up and down. The tray spring 64 biases the middle plate 63 upward, pressing the recording material P loaded on the middle plate 63 against the pickup roller 65. The front door 61 closes the recording material storage space when closed relative to the printer body 100, and supports the recording material P together with the tray section 62 and the middle plate 63 when open relative to the printer body 100.

[0023] The fixing unit 70 is a thermal fixing type that performs image fixing by heating and melting the toner on the recording material. The fixing unit 70 comprises a fixing film 71, a fixing heater such as a ceramic heater for heating the fixing film 71, a thermistor for measuring the temperature of the fixing heater, and a pressure roller 72 that presses against the fixing film 71.

[0024] Next, the image forming operation of the image forming apparatus 1 will be described. When an image forming command is input to the image forming apparatus 1, the image forming process by the image forming unit 10 is started based on image information input from an external computer or reading device 200 connected to the image forming apparatus 1. The scanner unit 11 irradiates the photosensitive drum 21 with laser light based on the input image information. At this time, the photosensitive drum 21 is pre-charged by the charging roller 22, and an electrostatic latent image is formed on the photosensitive drum 21 when the laser light is irradiated. Subsequently, this electrostatic latent image is developed by the developing roller 31, and a toner image is formed on the photosensitive drum 21.

[0025] In parallel with the image formation process described above, the pickup roller 65 of the feeding unit 60 feeds out the recording material P supported by the front door 61, tray unit 62, and middle plate 63. The recording material P is fed to the registration roller pair 15 by the pickup roller 65, and its skew is corrected when it abuts against the nip of the registration roller pair 15. The registration roller pair 15 is then driven in accordance with the timing of the toner image transfer and transports the recording material P toward the transfer nip formed by the transfer roller 12 and the photosensitive drum 21.

[0026] A transfer voltage is applied to the transfer roller 12, which acts as a transfer means, from a transfer high-voltage power supply, and the toner image supported on the photosensitive drum 21 is transferred to the recording material P, which is transported by the registration roller pair 15. The recording material P, on which the toner image has been transferred, is transported to the fixing unit 70, where the toner image is heated and pressurized as it passes through the nip between the fixing film 71 and the pressure roller 72 of the fixing unit 70. This causes the toner particles to melt and then solidify, fixing the toner image to the recording material P. The recording material P that has passed through the fixing unit 70 is discharged to the outside of the image forming apparatus 1 (outside the machine) by the discharge roller pair 80 and loaded onto the discharge tray 81 formed on the top of the printer body 100.

[0027] The discharge tray 81 is inclined upward toward the downstream direction in which the recording material is discharged, and the recording material discharged into the discharge tray 81 slides down the discharge tray 81 so that its rear end is aligned with the regulating surface 84.

[0028] As shown in Figures 4(a) and 4(b), the reading device 200 includes a reading unit 201 which houses a reading section (not shown) and a pressure plate 202 which is openably supported by the reading unit 201. The upper surface of the reading unit 201 is provided with a document glass 203 which transmits light emitted from the reading section and on which the document is placed.

[0029] When the user wants the scanner 200 to read the image of a document, the user places the document on the document glass 203 with the pressure plate 202 open. Then, by closing the pressure plate 202, the user prevents the document from shifting position on the document glass 203, and outputs a reading command to the image forming apparatus 1 by, for example, operating the control unit 300. When the reading operation starts, the reading unit within the reading unit 201 moves back and forth in the sub-scanning direction, that is, in the left-right direction with the control unit 300 of the image forming apparatus 1 facing forward. The reading unit emits light from the light-emitting unit towards the document, receives the light reflected by the document with the light-receiving unit, and reads the image of the document by converting it into photoelectric light. In the following, the forward-backward direction, left-right direction, and up-down direction are defined based on the state with the control unit 300 facing forward.

[0030] As shown in Figures 2(b) and 3, a first opening 101 that opens upward is formed on the top of the printer body 100, and the first opening 101 is covered by a top cover 82. The top cover 82, which serves as a loading tray, is supported so as to be able to open and close relative to the printer body 100 around a pivot axis 82c that extends in the left-right direction, and an output tray 81 that serves as a loading surface is formed on its upper surface. The top cover 82 opens from the front to the back when the reader 200 is open relative to the printer body 100. The reader 200 and the top cover 82 may be configured to be held in the open and closed states by a holding mechanism such as a hinge mechanism.

[0031] For example, if the recording material jams in the transport path CP through which the recording material fed by the pickup roller 65 passes, the user opens the top cover 82 together with the reader 200. The user then accesses the process unit 20 through the first opening 101 that is exposed when the top cover 82 is opened, and pulls the process unit 20 out along the process guide 102. The process guide 102 slides and guides the process unit 20 to a projection 21a (see Figure 5(a)) provided at the axial end of the photosensitive drum 21 of the process unit 20.

[0032] Then, when the process unit 20 is pulled out from the first opening 101, space is created to allow a hand to reach into the transport path CP. The user can reach into the printer body 100 through the first opening 101 and access the jammed recording material in the transport path CP, thereby processing the jammed recording material.

[0033] Furthermore, in this embodiment, as shown in Figures 1(b) and 4(c), an opening / closing member 83 is provided on the top cover 82 so as to be openable and closable. The discharge tray 81 of the top cover 82 has a second opening 82a formed therein, which is an opening that opens upward. The opening / closing member 83 is configured to move between a closed position, which covers the refill port 32a so that the toner pack 40 cannot be installed in the developing container 32, and an open position, which exposes the refill port 32a so that the toner pack 40 can be installed in the developing container 32. In the closed position, the opening / closing member 83 functions as part of the discharge tray 81. The opening / closing member 83 and the second opening 82a are formed on the left side of the discharge tray 81. The opening / closing member 83 is also supported on the top cover 82 so as to be openable and closable around a pivot axis 83a that extends in the front-rear direction, and can be opened to the left by placing a finger through a groove 82b provided in the top cover 82. Therefore, the user can access the refill port 32a simply by opening the opening / closing member 83. The opening / closing member 83 is formed in a roughly L-shape, following the shape of the top cover 82.

[0034] The second opening 82a of the output tray 81 is open so as to expose the toner replenishment port 32a formed at the top of the developing container 32, and when the opening / closing member 83 is opened, the user can access the replenishment port 32a without opening the top cover 82. In this embodiment, a method of replenishing toner from a toner pack 40 (see Figures 1(a) and 1(b)) filled with replenishment toner to the developing device 30 is adopted (direct replenishment method) while the developing device 30 is still attached to the image forming apparatus 1. Therefore, when the toner level in the process unit 20 becomes low, it is not necessary to remove the process unit 20 from the printer body 100 and replace it with a new process unit, thus improving usability. In addition, toner can be replenished to the developing container 32 at a lower cost than replacing the entire process unit 20. Furthermore, the direct replenishment method is more cost-effective than replacing only the developing device 30 of the process unit 20 because it does not require the replacement of various rollers, gears, etc.

[0035] [Collection of leftover toner] This embodiment employs a cleanerless configuration in which residual toner that remains on the photosensitive drum 21 without being transferred to the recording material P is collected in the developing unit 30 and reused. The residual toner is removed in the following steps. The residual toner contains a mixture of positively charged toner and negatively charged toner that does not have sufficient charge. The photosensitive drum 21 after transfer is discharged by the pre-exposure device 23, and a uniform discharge is generated by the charging roller 22, causing the residual toner to be negatively charged again. The residual toner, which has been negatively charged again in the charging section, reaches the developing section as the photosensitive drum 21 rotates. The surface area of ​​the photosensitive drum 21 that has passed through the charging section is then exposed by the scanner unit 11 with the residual toner still attached to the surface, and an electrostatic latent image is written.

[0036] Here, the behavior of the transfer residue toner that reaches the developing section will be explained separately for the exposed and unexposed sections of the photosensitive drum 21. The transfer residue toner adhering to the unexposed section of the photosensitive drum 21 is transferred to the developing roller 31 in the developing section due to the potential difference between the potential of the unexposed section (dark area potential) and the developing voltage, and is collected in the developing container 32. This is because, assuming that the normal charging polarity of the toner is negative, the developing voltage applied to the developing roller 31 is positive relative to the potential of the unexposed section. The toner collected in the developing container 32 is then mixed and dispersed with the toner in the developing container by the stirring member 34, and is then carried on the developing roller 31 for use in the developing process again.

[0037] On the other hand, the residual toner adhering to the exposure area of ​​the photosensitive drum 21 remains on the drum surface without being transferred from the photosensitive drum 21 to the developing roller 31 in the developing section. This is because, assuming that the normal charging polarity of the toner is negative, the developing voltage applied to the developing roller 31 is at a potential that is even more negative than the potential of the exposure area (bright area potential). The residual toner remaining on the drum surface, along with other toner transferred from the developing roller 31 to the exposure area, is carried on the photosensitive drum 21 and moves to the transfer section, where it is transferred to the recording material P.

[0038] As described above, this embodiment employs a cleanerless configuration in which the transfer residue toner is collected and reused in the developing unit 30. However, a conventional configuration in which the transfer residue toner is collected using a cleaning blade that contacts the photosensitive drum 21 may also be used. In that case, the transfer residue toner collected by the cleaning blade is collected in a collection container installed separately from the developing unit 30. However, by adopting a cleanerless configuration, the installation space for a collection container for collecting the transfer residue toner, etc., is not required, making it possible to further miniaturize the image forming apparatus 1. Furthermore, printing costs can be reduced by reusing the transfer residue toner.

[0039] [Developing container and toner pack configuration] Next, the configuration of the developing container 32 and the toner pack 40 as a replenishment container will be described. Figure 5(a) is a perspective view showing the developing container 32 and the toner pack 40, and Figure 5(b) is a front view showing the developing container 32 and the toner pack 40. Figure 6(a) is a cross-sectional view of 6A-6A in Figure 5(b), and Figure 6(b) is a cross-sectional view of 6B-6B in Figure 5(b).

[0040] As shown in Figures 5(a) to 6(b), the developing container 32 has a transport chamber 36 that houses the stirring member 34, and the transport chamber 36, which serves as a storage section for toner, extends along the entire length of the developing container 32 in the longitudinal direction LD (left-right direction). The transport chamber 36 is also integrally formed with a frame that rotatably supports the developing roller 31 and the supply roller 33, and houses the toner (developer) to be carried on the developing roller 31. The developing container 32 also has a first protrusion 37 that protrudes upward from one end in the longitudinal direction of the transport chamber 36 and communicates with the transport chamber 36, and a second protrusion 38 that protrudes upward from the other end in the longitudinal direction of the transport chamber 36. In other words, the first projection 37 is provided at one end of the developing container 32 in the direction of the rotation axis of the developing roller 31, i.e., in the longitudinal direction LD, and protrudes toward the discharge tray 81 in an intersecting direction that intersects the rotation axis direction from the central part of the developing container 32.

[0041] The second protrusion 38 is provided at the other end of the developing container 32 in the direction of the rotation axis of the developing roller 31, and protrudes toward the discharge tray 81 in a direction intersecting the center of the developing container 32. In this embodiment, the first protrusion 37 is formed on the left side of the developing container 32, and the second protrusion 38 is formed on the right side of the developing container 32. The upper end (tip) of the first protrusion 37 is provided with a mounting portion 57 to which a toner pack 40 can be attached, and the mounting portion 57 has a supply port 32a for supplying developer from the toner pack 40 to the transport chamber 36. The toner pack 40 can be attached to the mounting portion 57 in a state where it is exposed to the outside of the device.

[0042] The first protrusion 37 and the second protrusion 38 extend diagonally from the transport chamber 36 toward the front and upward of the device. That is, the first protrusion 37 and the second protrusion 38 protrude downstream and upward in the discharge direction of the discharge roller pair 80. As a result, the replenishment port 32a formed in the first protrusion 37 is located on the front side of the image forming apparatus 1, making it easy to replenish toner to the developing container 32.

[0043] In particular, in this embodiment, since the reading device 200, which can be opened and closed mainly on the rear side of the device, is positioned above the opening / closing member 83, placing the toner refill port 32a in front of the device allows for more effective use of the space between the refill port 32a and the reading device 200. This improves the work efficiency when refilling toner from the refill port 32a.

[0044] The upper parts of the first protrusion 37 and the second protrusion 38 are connected by a handle portion 39, which serves as a connecting portion. Between the handle portion 39 and the transport chamber 36, a laser passage space SP is formed, which is an air gap through which the laser L (see Figure 1(a)) emitted from the scanner unit 11 (see Figure 1(a)) toward the photosensitive drum 21 can pass.

[0045] The handle portion 39 has a gripping portion 39a that the user can grasp by placing their fingers on it, and the gripping portion 39a is formed to protrude upward from the top surface of the handle portion 39. The first protrusion portion 37 is formed to be hollow inside, and a refill port 32a is formed on its upper surface. The refill port 32a is configured to be connectable to the toner pack 40.

[0046] By providing a first protrusion 37, with a supply port 32a formed at its tip, on one side in the longitudinal direction of the developing container 32, a laser passage space SP through which the laser L emitted from the scanner unit 11 can pass can be secured, and the image forming apparatus 1 can be miniaturized. Furthermore, by providing a second protrusion 38 on the other side in the longitudinal direction of the developing container 32 and forming a handle portion 39 connecting the first protrusion 37 and the second protrusion 38, usability when removing the process unit 20 from the printer body 100 can be improved. The second protrusion 38 may be formed in a hollow shape, similar to the first protrusion 37, or it may be solid.

[0047] As shown in Figures 5(a) to 6(b), the toner pack 40 is configured to be detachably attached to the mounting portion 57 of the first protrusion 37. The toner pack 40 also has a shutter member 41 provided at the opening that can be opened and closed, and a plurality of projections 42 formed corresponding to a plurality of grooves 32b formed in the mounting portion 57 (three in this embodiment). When the user replenishes toner in the developing container 32, the user aligns the projections 42 of the toner pack 40 so that they pass through the grooves 32b of the mounting portion 57, and connects the toner pack 40 to the mounting portion 57. When the toner pack 40 is rotated 180 degrees in this state, the shutter member 41 of the toner pack 40 abuts against an unshown abutment portion of the mounting portion 57, causing the toner pack 40 to rotate relative to the body of the toner pack 40, and the shutter member 41 opens. As a result, the toner contained in the toner pack 40 leaks out of the toner pack 40, and the leaked toner enters the hollow first protrusion 37 through the replenishment port 32a. The shutter member 41 may be provided on the side of the replenishment port 32a.

[0048] The first projection 37 has a slope 37a positioned opposite the opening of the supply port 32a, and the slope 37a slopes downward toward the conveying chamber 36. Therefore, the toner supplied from the supply port 32a is guided toward the conveying chamber 36 by the slope 37a. The stirring member 34, as shown in Figures 6(a) and 6(b), has a stirring shaft 34a extending in the longitudinal direction and a blade portion 34b extending radially outward from the stirring shaft 34a. The blade portion 34b is a flexible sheet.

[0049] Toner supplied from the supply port 32a, located upstream of the conveying direction of the agitator 34, is fed towards the developing roller 31 and the supply roller 33 as the agitator 34 rotates. The conveying direction of the agitator 34 is parallel to the longitudinal direction LD of the developing container 32 (see Figure 5(b)). The supply port 32a and the first projection 37 are located at one end of the developing container 32 in the longitudinal direction LD, but by repeatedly rotating the agitator 34, the toner is distributed throughout the entire length of the developing container 32. In this embodiment, the agitator 34 is composed of an agitator shaft 34a and a blade portion 34b, but a spiral-shaped agitator shaft may be used to distribute the toner throughout the entire length of the developing container 32.

[0050] In this embodiment, the toner pack 40 is made of a deformable plastic bag, as shown in Figures 7 and 8(a), but is not limited to this. For example, the toner pack may be made of a substantially conical bottle container 40B as shown in Figure 8(b), or of a paper container 40C as shown in Figure 8(c). In any case, the material and shape of the toner pack can be anything. Furthermore, the method for discharging toner from the toner pack is preferably by the user squeezing it with their fingers if it is the toner pack 40 or paper container 40C, or by the user vibrating the container by tapping it or the like to cause it to leak out if it is the bottle container 40B. In addition, a discharge mechanism may be provided inside the bottle container 40B to discharge toner from the bottle container 40B. Furthermore, the discharge mechanism may be configured to engage with the printer body 100 and receive driving force from the printer body 100.

[0051] Furthermore, the shutter member 41 may be omitted in any toner pack, and a sliding shutter member may be used instead of the rotating shutter member 41. Also, the shutter member 41 may be configured to be destroyed when the toner pack is installed in the supply port 32a or when the toner pack is rotated while installed, or it may be a removable lid structure such as a seal.

[0052] [Method for detecting toner level] Next, a method for detecting the remaining toner in the developing container 32 will be explained using Figures 9(a) to 11(b). Figure 9(a) is a cross-sectional view showing the toner remaining sensor 51, and Figure 9(b) is a schematic cross-sectional view of the 9B-9B cross section of Figure 9(a) viewed from the developing roller 31 side toward the developing container 32. Figure 10 is a circuit diagram showing an example of the circuit configuration of the toner remaining sensor 51.

[0053] As shown in Figures 9(a) and 9(b), the developing container 32 of this embodiment is equipped with a toner level sensor 51 that detects the remaining amount of toner according to the amount of toner remaining in the transport chamber 36. The toner level sensor 51 is located on the side of the developing container 32 opposite to the developing roller 31, i.e., side 36a, and has a light-emitting unit 51a and a light-receiving unit 51b. The light-emitting unit 51a and the light-receiving unit 51b are arranged side by side in the longitudinal direction LD of the process unit 20. Light emitted from the light-emitting unit 51a passes inside the transport chamber 36 and is received by the light-receiving unit 51b. That is, the light-emitting unit 51a and the light-receiving unit 51b form an optical path Q1 inside the transport chamber 36. The optical path Q1 extends in the longitudinal direction LD. The light-emitting unit 51a and the light-receiving unit 51b may be arranged inside the transport chamber 36, respectively, or the light-emitting unit and the light-receiving unit may be arranged outside the transport chamber 36, and the light may be guided inside and outside the transport chamber 36 by a light guide.

[0054] Furthermore, the light-emitting unit 51a and the light-receiving unit 51b are located in the central part of the transport chamber 36 in the longitudinal direction LD. More specifically, the light-emitting unit 51a and the light-receiving unit 51b are located in the region AR1 corresponding to the laser passage space SP in the longitudinal direction LD. The light-emitting unit 51a is located in the longitudinal direction LD between the supply port 32a and the central part 31a of the developing roller 31. The dashed line in Figure 9(b) indicates the position corresponding to the central part 31a of the developing roller 31. The central part 31a of the developing roller 31 is located between the light-emitting unit 51a and the light-receiving unit 51b in the longitudinal direction LD. By locating the light-emitting unit 51a and the light-receiving unit 51b in the central part of the transport chamber 36 in this way, the remaining amount of toner in the transport chamber 36 can be detected accurately. In other words, while the developer (toner) may be unevenly distributed at the ends of the longitudinal LD ​​in the transport chamber 36, the central part of the transport chamber 36 has less uneven distribution of the developer, making it possible to detect the actual remaining amount of toner.

[0055] In Figure 10, an LED is used for the light-emitting unit 51a and a phototransistor that turns on when light from the LED is used for the light-receiving unit 51b, but the system is not limited to this. For example, a halogen lamp or fluorescent lamp may be used for the light-emitting unit 51a, and a photodiode or avalanche photodiode may be used for the light-receiving unit 51b. A switch (not shown) is provided between the light-emitting unit 51a and the power supply voltage Vcc. When the switch is turned on, the voltage from the power supply voltage Vcc is applied to the light-emitting unit 51a, causing the light-emitting unit 51a to become conductive. On the other hand, a switch (not shown) is also provided between the light-receiving unit 51b and the power supply voltage Vcc. When the switch is turned on, the light-receiving unit 51b becomes conductive due to a current corresponding to the detected amount of light.

[0056] The light-emitting unit 51a is connected to a power supply voltage Vcc and a current-limiting resistor R1, and the light-emitting unit 51a emits light according to the current determined by the current-limiting resistor R1. The light emitted from the light-emitting unit 51a passes through the optical path Q1 as shown in Figure 9(b) and is received by the light-receiving unit 51b. The power supply voltage Vcc is connected to the collector terminal of the light-receiving unit 51b, and a detection resistor R2 is connected to the emitter terminal. The light-receiving unit 51b, which is a phototransistor, receives the light emitted from the light-emitting unit 51a and outputs a signal (current) corresponding to the amount of light received. This signal is converted to a voltage V1 by the detection resistor R2 and input to the A / D conversion unit 95 of the control unit 90 (see Figure 12). In other words, the light-receiving unit 51b changes its output value according to the amount of toner (developer) contained in the transport chamber 36.

[0057] The control unit 90 (CPU 91) determines whether the light receiving unit 51b has received light from the light emitting unit 51a based on the input voltage level. The control unit 90 (CPU 91) calculates the amount of toner (amount of developer) in the developing container 32 based on the length of time the light receiving unit 51b detected each light and the received light intensity when the toner in the developing container 32 was stirred for a certain period of time by the stirring member 34. In other words, the ROM 93 has in advance stored a table that can output the remaining amount of toner from the light reception time and light intensity when the toner was transported by the stirring member 34, and the control unit 90 predicts / calculates the remaining amount of toner based on the input to the A / D conversion unit 95 and the table.

[0058] More specifically, as shown in Figure 9(a), the optical path Q1 of the toner level sensor 51 is set to overlap with the rotational trajectory T of the stirring member 34 when viewed in the axial direction of the stirring member 34's rotation axis. In other words, the light emitted from the light-emitting part 51a of the toner level sensor 51 passes inside the transport chamber 36 within the rotational trajectory of the stirring member 34 when viewed in the axial direction of the stirring member 34. The time during which the optical path Q1 is blocked by the toner transported by the stirring member 34 during one rotation of the stirring member 34, that is, the time during which the light-receiving part 51b does not detect light from the light-emitting part 51a, changes depending on the remaining toner level. The light-receiving intensity at the light-receiving part 51b also changes depending on the remaining toner level.

[0059] In other words, when there is a lot of toner remaining, the optical path Q1 is more easily blocked by the toner, so the time that the light receiving unit 51b receives light becomes shorter, and the light intensity received by the light receiving unit 51b becomes lower. On the other hand, when there is little toner remaining, conversely, the time that the light receiving unit 51b receives light becomes longer, and the light intensity received by the light receiving unit 51b becomes stronger. Therefore, the control unit 90 can determine the toner level based on the light receiving time and light intensity of the light receiving unit 51b as follows.

[0060] For example, as shown in Figure 11(a), when there is a small amount of toner in the transport chamber 36 of the developing container 32, the time during which the light receiving unit 51b receives light increases, and the intensity of the light received by the light receiving unit 51b increases, so it is determined that there is little toner remaining. On the other hand, as shown in Figure 11(b), when there is a lot of toner in the transport chamber 36 of the developing container 32, the time during which the light receiving unit 51b receives light decreases, and the intensity of the light received by the light receiving unit 51b decreases, so it is determined that there is a lot of toner remaining.

[0061] Furthermore, the method for detecting / estimating the remaining toner is not limited to the optical toner detection method described in Figure 9, and various well-known methods for detecting / estimating the remaining toner can be adopted. For example, two or more metal plates or conductive resin sheets extending in the longitudinal direction of the developing rollers may be placed on the inner wall of the developing container 32, which is the frame, and the capacitance between the two metal plates or conductive resin sheets may be measured to detect / estimate the remaining toner. Alternatively, a load cell may be provided to support the developing device 30 from below, and the CPU 51 may calculate the remaining toner by subtracting the weight of the developing device 30 when the toner is empty from the weight measured by the load cell.

[0062] [Control system for image forming apparatus] Figure 12 is a block diagram showing the control system of the image forming apparatus 1. The control unit 90, which serves as the control means for the image forming apparatus 1, includes a CPU 91 as an arithmetic unit, a RAM 92 used as the work area for the CPU 91, and a ROM 93 for storing various programs. The control unit 90 also includes an I / O interface 94 as an input / output port for connecting to external devices, and an A / D conversion unit 95 for converting analog signals into digital signals.

[0063] The input side of the control unit 90 is connected to a toner level sensor 51, a mounting sensor 53, and an open / close sensor 54. The mounting sensor 53 detects when the toner pack 40 is mounted in the replenishment port 32a of the developing container 32. For example, the mounting sensor 53 consists of a pressure-sensitive switch provided in the replenishment port 32a that outputs a detection signal when pressed by a projection 42 on the toner pack 40. The open / close sensor 54 detects whether the open / close member 83 has been opened relative to the top cover 82. The open / close sensor 54 consists of, for example, a pressure-sensitive switch or a magnetic sensor.

[0064] Furthermore, the control unit 90 is connected to an operation unit 300, an image forming unit 10, and a toner level panel 400 which serves as a notification means capable of notifying information regarding the remaining toner level. The operation unit 300 has a display unit 301 capable of displaying various setting screens and physical keys, etc. The display unit 301 is composed of, for example, a liquid crystal panel. The image forming unit 10 has a motor M1 as a drive source for driving the photosensitive drum 21, developing roller 31, supply roller 33, and agitation member 34, etc. Note that the photosensitive drum 21, developing roller 31, supply roller 33, and agitation member 34 may each be configured to be driven by separate motors.

[0065] As shown in Figures 1(b) and 13(a) to 13(d), the toner level panel 400 is located on the right side of the front of the printer body 100, that is, on the opposite side from the operation unit 300 located on the left side, and displays information regarding the remaining toner in the developing container 32. In this embodiment, the toner level panel 400 is a panel member consisting of multiple (three in this embodiment) scales arranged vertically, with each scale corresponding to Low level, Mid level, and Full level.

[0066] Specifically, as shown in Figure 13(a), when only the lower scale is blinking, the toner level in the developing container 32 is at the NearOut level. As shown in Figure 13(b), when only the lower scale is lit, the toner level in the developing container 32 is at the Low level. As shown in Figure 13(c), when the lower and middle scales are lit and the upper scale is off, the toner level in the developing container 32 is at the Mid level. As shown in Figure 13(d), when all three scales are lit, the toner level in the developing container 32 is at the Full level.

[0067] The NearOut level indicates the amount of toner remaining in the developing container 32, which is about to run out and will no longer be able to properly form an image. The Low level indicates a toner level higher than the NearOut level and lower than the Mid level. The Mid level indicates a toner level higher than the Low level and lower than the Full level.

[0068] The toner level panel 400 is not limited to a liquid crystal panel; it may also consist of a light source such as an LED or incandescent lamp and a diffusion lens. Alternatively, instead of providing a separate toner level panel 400, the toner level may be displayed on the display of the operation unit 300 using the scales described in this embodiment. Furthermore, when the toner level in the developing container 32 reaches a low level, a toner replenishment notification may be displayed on the operation unit 300 to prompt to replenish the toner. Also, when the toner runs out, a toner replenishment notification may be displayed on the operation unit 300 to prompt to replenish the toner.

[0069] Furthermore, although this embodiment describes a configuration that displays four states using three scales, the number of scales is not limited to this and may be set appropriately according to the configuration of the image forming apparatus. In addition, the toner level may be continuously displayed using a percentage display or gauge display. Furthermore, notification of the toner level to the user may be given by voice using a speaker.

[0070] Furthermore, in the examples shown in Figures 13(a) to (d), the toner level panel 400 was described as a notification means for indicating the remaining toner level, but this is not limited to this. For example, the display in Figure 13(b) could be used to indicate that toner replenishment is needed, the display in Figure 13(c) could be used to indicate that toner replenishment is not needed, and the display in Figure 13(d) could be used to indicate that sufficient toner has been replenished.

[0071] As described above, in this embodiment, the process unit 20, which includes a transport chamber 36 for storing toner, is provided with a light-emitting section 51a and a light-receiving section 51b of the toner level sensor 51. Therefore, the relative position of the optical path Q1 in the transport chamber 36 remains constant, and the remaining toner level can be stably detected regardless of the positional accuracy of the process unit 20 relative to the printer body 100.

[0072] Furthermore, since the relative position of the optical path Q1 in the transport chamber 36 remains constant, there is no need to design the toner level sensor 51 and the developing container 32 in advance, taking into account any positional misalignment between the transport chamber 36 and the optical path Q1. For this reason, for example, there is no need to select optical elements with a margin in the light intensity of the toner level sensor 51, thereby improving the design flexibility of the toner level sensor 51 and the developing container 32 and reducing costs.

[0073] Furthermore, the light-emitting unit 51a and the light-receiving unit 51b in this embodiment are arranged side by side along the longitudinal LD ​​of the process unit 20, and are located on the same side (front side) relative to the transport chamber 36 when viewed along the longitudinal LD. Therefore, the light-emitting unit 51a and the light-receiving unit 51b can be arranged compactly, and the power supply configuration that supplies power to the light-emitting unit 51a and the light-receiving unit 51b can also be arranged compactly. Thus, the process unit 20 can be miniaturized.

[0074] This embodiment employs a direct supply method in which toner is supplied directly to the developing container 32 via a toner pack 40 from the supply port 32a. Therefore, there is no need to remove the process unit 20 when supplying toner to the developing container 32. Furthermore, the supply port 32a of the developing container 32 is formed on the upper surface of a first projection 37 that protrudes upward from one end in the longitudinal direction of the transport chamber 36, and is therefore located close to the second opening 82a. As a result, the user can easily supply toner to the developing container 32 via the supply port 32a. In addition, since parts such as the developing roller 31 and supply roller 33 are not replaced when supplying toner to the developing container 32, costs can be reduced.

[0075] Furthermore, since the laser passage space SP is formed so as to be surrounded by the first protrusion 37, the second protrusion 38, the handle portion 39, and the transport chamber 36, the developing container 32 and the scanner unit 11 can be placed in close proximity, and the image forming apparatus 1 can be miniaturized.

[0076] Furthermore, when the toner pack 40 is inserted into the refill port 32a and the toner refilling operation is performed, the stirring member 34 is driven, so even if the refill port 32a is located at one end in the longitudinal direction of the developing container 32, the packing phenomenon can be reduced. This reduces image defects and improves the accuracy of toner remaining amount detection by the light-emitting unit 51a and the light-receiving unit 51b.

[0077] <Second Embodiment> Next, a second embodiment of the present invention will be described. The second embodiment is a modification of the configuration of the developing apparatus 30 in the first embodiment. For this reason, components similar to those in the first embodiment will not be shown in the illustration, or will be described using the same reference numerals in the illustration.

[0078] The developing apparatus 330 according to this embodiment will be described with reference to Figures 14 to 17. The developing apparatus 330 constitutes a part of the process unit 20 (see Figure 3). Figure 14 is a perspective view showing the developing apparatus 330. Figure 15(a) is a perspective view showing the substrate 700 and substrate holding member 710 assembled on the developing container lid 321. Figure 15(b) is a perspective view showing the substrate 700 and substrate holding member 710, and Figure 15(c) is another perspective view showing the substrate 700 and substrate holding member 710. Figure 16(a) is a cross-sectional view of the developing apparatus 330 passing through the light-emitting section 510a, and Figure 16(b) is a cross-sectional view taken along line 16B-16B in Figure 16(a). Figure 17(a) is a cross-sectional view showing the developing container 320 with a low toner level, and Figure 17(b) is a cross-sectional view showing the developing container 320 with a high toner level.

[0079] As shown in Figure 14, the developing device 330 includes a developing container 320 and a developing container lid 321, which are connected by a connecting part 322. The developing container 320, the developing container lid 321, and the connecting part 322 constitute the frame 340 of the developing device 330. The frame 340 is provided with a transport chamber 36 (see Figure 16(a)) for containing a developer containing toner (hereinafter referred to as toner). The developing roller 31 is supported by the frame 340.

[0080] The developing container lid 321, which constitutes part of the frame 340, has substrate positioning parts 321a and 321b and substrate fixing parts 321c and 321d, and an optical path guide 610 is installed between the substrate fixing parts 321c and 321d of the developing container lid 321. The optical path guide 610 has a first guide part 610a and a second guide part 610b, and the first guide part 610a guides the light emitted from the light-emitting part 510a (described later) into the transport chamber 36 of the developing container 320. The second guide part 610b, the first guide part 610a and the light that has passed through the transport chamber 36 are guided to the light-receiving part 510b (described later).

[0081] The substrate positioning parts 321a and 321b are located outside the substrate fixing parts 321c and 321d in the longitudinal LD ​​of the developing container 320, and have a boss shape that protrudes away from the developing container 320. The shape of the substrate positioning parts 321a and 321b is not limited to a boss shape and may be any shape. The longitudinal LD ​​of the developing container 320 is the same as the longitudinal LD ​​of the process unit 20 (see Figure 5(a)). Fasteners such as screws can be screwed into the substrate fixing parts 321c and 321d.

[0082] In this embodiment, as shown in Figure 15(a), the substrate 700 and the substrate holding member 710 are assembled to the developing container lid 321. The substrate holding member 710 is assembled to the developing container lid 321 while being sandwiched between the developing container lid 321 and the substrate 700.

[0083] As shown in Figure 15(b), the substrate 700 is provided on the surface facing the substrate holding member 710 and has a light-emitting unit 510a and a light-receiving unit 510b for detecting the remaining amount of toner in the transport chamber 36. In this embodiment, an LED is used for the light-emitting unit 510a and a phototransistor that turns on when light from the LED is used for the light-receiving unit 510b, but it is not limited to these. For example, a halogen lamp or fluorescent lamp may be used for the light-emitting unit 510a, and a photodiode or avalanche photodiode may be used for the light-receiving unit 510b.

[0084] Furthermore, the substrate 700 has positioning holes 700a and 700b through which the substrate positioning parts 321a and 321b are inserted and engage, and substrate fixing holes 700c and 700d through which screws that are screwed into the substrate fixing parts 321c and 321d can pass.

[0085] Similarly, the substrate holding member 710 has positioning holes 710a and 710b through which the substrate positioning parts 321a and 321b are inserted and engage, and substrate fixing holes 710c and 710d through which screws that are screwed into the substrate fixing parts 321c and 321d can pass. Furthermore, the substrate holding member 710 has a first hole 711a into which the first guide part 610a of the optical path guide 610 is inserted, and a second hole 711b into which the second guide part 610b of the optical path guide 610 is inserted. These first hole 711a and second hole 711b have a cylindrical shape. The substrate holding member 710, as a holder, holds the substrate 700.

[0086] Furthermore, light-shielding plates 710e and 710f are provided on the side of the substrate holding member 710 facing the substrate 700, serving as shielding parts. These light-shielding plates 710e and 710f are positioned between the light-emitting part 510a and the light-receiving part 510b when the substrate 700 and the substrate holding member 710 are assembled to the developing container lid 321, and are also provided in close proximity to the substrate 700.

[0087] As shown in Figures 14 to 16(a), the substrate holding member 710 is positioned relative to the developing container lid 321 by the substrate positioning 321a and 321b of the developing container lid 321 penetrating and engaging with the positioning holes 710a and 710b. Similarly, the substrate 700 is positioned relative to the developing container lid 321 by the substrate positioning 321a and 321b of the developing container lid 321 penetrating and engaging with the positioning holes 700a and 700b. In this way, by using the substrate positioning 321a and 321b in common for positioning the substrate holding member 710 and the substrate 700, the developing container lid 321, the substrate holding member 710, and the substrate 700 can be positioned with higher precision.

[0088] Furthermore, with the substrate holding member 710 and the substrate 700 positioned relative to the developing container lid 321, screws are inserted into the substrate fixing holes 700c, 700d, 710c, and 710d, and the screws are screwed into the substrate fixing portions 321c and 321d of the developing container lid 321. As a result, the substrate holding member 710 and the substrate 700 are fastened together with the developing container lid 321 by the screws, and the substrate holding member 710 and the substrate 700 are fixed to the developing container lid 321.

[0089] As shown in Figures 14 to 16(b), when the substrate holding member 710 and the substrate 700 are assembled to the developing container lid 321, the first guide portion 610a of the optical path guide 610 is inserted into the first hole 711a of the substrate holding member 710. The first guide portion 610a is then positioned in close proximity to the light-emitting portion 510a of the substrate 700. Similarly, the second guide portion 610b of the optical path guide 610 is inserted into the second hole 711b of the substrate holding member 710. The second guide portion 610b is then positioned in close proximity to the light-receiving portion 510b of the substrate 700.

[0090] As described above, since the substrate holding member 710 and the substrate 700 are precisely positioned on the developing container lid 321, the light emitted from the light-emitting unit 510a is reliably guided by the first guide unit 610a. The light guided by the first guide unit 610a into the transport chamber 36 inside the developing container 320 is then emitted from the first guide unit 610a toward the longitudinal LD.

[0091] Then, the light traveling along the optical path Q2 inside the transport chamber 36 is guided to the outside of the developing container 320 by the second guide unit 610b. Since the second guide unit 610b is positioned close to the light receiving unit 510b, the light emitted from the second guide unit 610b is reliably received by the light receiving unit 510b. Therefore, the accuracy of toner level detection by the light emitting unit 510a and the light receiving unit 510b can be improved.

[0092] Furthermore, light-shielding plates 710e and 710f are positioned between the light-emitting unit 510a and the light-receiving unit 510b, and are located close to the substrate 700. Therefore, light emitted from the light-emitting unit 510a that travels to the light-receiving unit 510b without passing through the first guide unit 610a and the second guide unit 610b is shielded by the light-shielding plates 710e and 710f. In particular, in this embodiment, an LED element is used for the light-emitting unit 510a, which has weaker directionality compared to, for example, a bullet-shaped LED, and it is desirable to shield the light that travels directly from the light-emitting unit 510a to the light-receiving unit 510b. Thus, false detections caused by light that does not pass through the optical path Q2 being received by the light-receiving unit 510b are suppressed, and the accuracy of toner level detection by the light-emitting unit 510a and the light-receiving unit 510b can be improved.

[0093] Here, the arrangement of the light-emitting unit 510a and the light-receiving unit 510b will be explained in more detail. As shown in Figures 16(a) and 16(b), the light-emitting unit 510a and the light-receiving unit 510b are located on the side 36a of the frame 340 opposite to the developing roller 31. The light-emitting unit 510a and the light-receiving unit 510b are located in the central part of the transport chamber 36 in the longitudinal direction LD. More specifically, the light-emitting unit 510a and the light-receiving unit 510b are located in the region AR1 corresponding to the laser passage space SP in the longitudinal direction LD (see Figure 9(b)). The light-emitting unit 510a is located in the longitudinal direction LD between the supply port 32a and the central part 31a of the developing roller 31. The dashed line in Figure 16(b) indicates the position corresponding to the central part 31a of the developing roller 31. The central part 31a of the developing roller 31 is located between the light-emitting unit 510a and the light-receiving unit 510b in the longitudinal direction LD. In this way, by locating the light-emitting unit 510a and the light-receiving unit 510b in the central part of the transport chamber 36, the remaining amount of toner in the transport chamber 36 can be detected accurately. That is, while the developer (toner) may be unevenly distributed at the ends of the longitudinal LD ​​of the transport chamber 36, the uneven distribution of the developer is less in the central part of the transport chamber 36, so the actual amount of toner remaining can be detected.

[0094] The method for detecting the remaining toner level is the same as the method described in the first embodiment using, for example, Figures 10-13. As shown in Figure 16(a), the optical path Q2 is set to overlap with the rotation trajectory T of the stirring member 34 when viewed in the axial direction of the stirring member 34's rotation axis. In other words, the light emitted from the light-emitting unit 510a passes through the inside of the transport chamber 36 within the rotation trajectory of the stirring member 34 when viewed in the axial direction of the stirring member 34. The time during which the optical path Q2 is blocked by the toner transported by the stirring member 34 during one rotation of the stirring member 34, that is, the time during which the light-receiving unit 51b does not detect light from the light-emitting unit 51a, changes depending on the remaining toner level. The light-receiving intensity at the light-receiving unit 51b also changes depending on the remaining toner level. As a result, the control unit 90 can determine the remaining toner level.

[0095] For example, as shown in Figure 17(a), when there is a small amount of toner in the transport chamber 36 of the developing container 320, the time during which the light receiving unit 510b receives light increases, and the intensity of the light received by the light receiving unit 510b increases, so it is determined that there is little toner remaining. On the other hand, as shown in Figure 17(b), when there is a lot of toner in the transport chamber 36 of the developing container 320, the time during which the light receiving unit 510b receives light decreases, and the intensity of the light received by the light receiving unit 510b decreases, so it is determined that there is a lot of toner remaining. The display of the toner remaining level by the toner remaining panel 400 is as explained in Figures 13(a) to (d).

[0096] As described above, in this embodiment, a substrate holding member 710 and a substrate 700 are attached to a process unit 20 which includes a developing container 320 (or transport chamber 36) for containing toner, and a light-emitting part 510a and a light-receiving part 510b are provided on the substrate 700. Therefore, the relative position of the optical path Q2 in the transport chamber 36 is constant, and the remaining toner amount can be stably detected regardless of the positional accuracy of the process unit 20 relative to the printer body 100.

[0097] Furthermore, since the relative position of the optical path Q2 in the transport chamber 36 remains constant, there is no need to design the light-emitting unit 510a, the light-receiving unit 510b, and the developing container 320 in advance, taking into account any positional misalignment between the transport chamber 36 and the optical path Q2. For this reason, for example, there is no need to select optical elements with a margin in the light intensity of the light-emitting unit 510a, thereby improving the design flexibility of the light-emitting unit 510a, the light-receiving unit 510b, and the developing container 32, and reducing costs.

[0098] Furthermore, since the substrate positioning elements 321a and 321b provided on the developing container lid 321 are used in common for positioning the substrate holding member 710 and the substrate 700, the developing container lid 321, the substrate holding member 710, and the substrate 700 can be positioned with higher precision.

[0099] Furthermore, by interposing the substrate holding member 710, which has a first guide portion 610a, a second guide portion 610b, and light-shielding plates 710e and 710f, between the developing container lid 321 and the substrate 700, it is possible to reduce the amount of light that does not pass through the optical path Q2 that is received by the light-receiving portion 510b. As a result, false detection by the light-receiving portion 510b is suppressed, and the accuracy of toner level detection by the light-emitting portion 510a and the light-receiving portion 510b can be improved.

[0100] Furthermore, in this embodiment, the light-emitting unit 510a and the light-receiving unit 510b are arranged side by side along the longitudinal LD ​​of the process unit 20, and are located on the same side (front side) relative to the transport chamber 36 when viewed along the longitudinal LD. This allows the light-emitting unit 510a and the light-receiving unit 510b to be arranged compactly. Also, since the light-emitting unit 510a and the light-receiving unit 510b are provided together on the substrate 700, power can be easily supplied to the light-emitting unit 510a and the light-receiving unit 510b, and signal exchange with the light-emitting unit 510a and the light-receiving unit 510b can be easily performed. Thus, the process unit 20 can be miniaturized. A connector is provided on the substrate 700, and this connector is connected to the control unit 90 provided on the printer body 100 by a cable. When attaching or detaching the process unit 20 to the printer body 100, the cable and connector are attached and detached.

[0101] <Other embodiments> In the first embodiment described above, the toner level sensor 51, which includes the light-emitting unit 51a and the light-receiving unit 51b, was installed in the developing device 30. However, the light-emitting unit 51a and the light-receiving unit 51b may be provided on the substrate.

[0102] Furthermore, in the second embodiment described above, a substrate holding member 710 was provided between the developing container lid 321 and the substrate 700, but the invention is not limited to this. That is, the substrate 700 may be directly attached to the developing container lid 321 without providing the substrate holding member 710.

[0103] In the second embodiment, the developing container lid 321 is provided with substrate positioning parts 321a and 321b, and these positioning parts engage with the positioning holes 710a and 710b of the substrate holding member 710 and the positioning holes 700a and 700b of the substrate 700, but the embodiment is not limited to this. For example, boss-shaped positioning parts may be made to protrude from both sides of the substrate holding member 710, and these may be engaged with holes provided in the developing container lid 321 and the substrate 700, respectively. For example, boss-shaped positioning parts may be provided on the substrate 700, and holes provided in the developing container lid 321 and the substrate holding member 710 may be engaged with these positioning parts, respectively. In any case, the method and position of positioning the substrate 700 on the process unit 20, as well as the method and position of fixing it, are not limited.

[0104] Furthermore, in all of the above-described configurations, the light-emitting unit and the light-receiving unit are arranged side by side in the longitudinal direction of the LD, but are not limited to this. That is, the light-emitting unit and the light-receiving unit may be arranged in any position as long as they are located on the side of the transport chamber 36 opposite to the developing roller 31.

[0105] Furthermore, in all of the embodiments described above, the optical paths Q1 and Q2 were arranged to overlap with the rotational trajectory T of the stirring member 34 when viewed in the axial direction of the stirring member 34, but this is not limited to this. That is, the optical paths Q1 and Q2 may be arranged so as not to overlap with the rotational trajectory T of the stirring member 34.

[0106] In all of the configurations described above, the reading device 200 was provided above the printer body, but this is not the only configuration. That is, the image forming apparatus may be a printer without a reading device. Also, the reading device may be a reading device equipped with an ADF (Auto Document Feeder) for feeding documents. [Explanation of symbols]

[0107] 1: Image forming apparatus / 20: Process unit / 21: Image carrier (photosensitive drum) / 31: Developer carrier (developing roller) / 31a: Central part / 32: Frame (developing container) / 32a: Refill port / 34: Agitation member / 36: Storage section (transport chamber) / 40: Refill container (toner pack) / 51a, 510a: Light-emitting part / 51b, 510b: Light-receiving part / 100: Printer body (device body) / 321a, 321b: Positioning part (substrate positioning) / 340: Frame / 610a: First guide part / Second guide part / 700: Substrate / 710: Holder (substrate holding member) / 710e, 710f: Shielding part (light-shielding plate) / 711a: First hole part / 711b: Second hole part / LD: Longitudinal direction

Claims

1. An image forming apparatus, A device body having a control unit, A process unit attached to the main body of the apparatus, comprising: a roller; a frame comprising a housing for containing a developer to be carried on the roller, with the direction of the roller's rotation axis being in the longitudinal direction; and an electrical circuit board electrically connected to the control unit; Equipped with, The electrical circuit board is provided with a light-emitting element that emits light and a light-receiving element that receives light emitted from the light-emitting element and that has passed through the inside of the housing. The electrical circuit board is supported in the central part of the frame in the longitudinal direction. An image forming apparatus characterized by the following features.

2. The light-emitting element and the light-receiving element are aligned in the longitudinal direction. The image forming apparatus according to feature 1.

3. The frame rotatably supports the roller at one end in a direction perpendicular to the longitudinal direction, and supports the electrical substrate at the other end in the same perpendicular direction. The image forming apparatus according to feature 1.

4. The process unit is provided with an inlet for receiving developer to be supplied to the storage section. The light-emitting element and the light-receiving element are provided at positions different from the receiving opening in the longitudinal direction. The image forming apparatus according to feature 1.

5. The light-emitting element is provided between the center of the roller in the longitudinal direction and the receiving port. The image forming apparatus according to feature 4.

6. The light-receiving element is provided in the longitudinal direction on the side of the roller opposite to the light-emitting element with respect to the center. The image forming apparatus according to feature 5.

7. The process unit has a support member that supports the electrical substrate, The support member is fixed to the frame. The image forming apparatus according to feature 1.

8. The process unit has a stirring member that rotates to agitate the developer contained in the storage section, the stirring member having a rotating shaft extending in the longitudinal direction and a sheet fixed to the rotating shaft, When the stirring member is rotating, the sheet passes through the optical path of the light emitted from the light-emitting element. The image forming apparatus according to feature 1.

9. The process unit has a photosensitive drum from which developer is supplied from the roller. The image forming apparatus according to feature 1.

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