Image forming apparatus

Abstract

To provide a technique that can detect the phase of a stirring member by a simple method in an image forming apparatus having optical toner remaining amount detection means.SOLUTION: An image forming apparatus comprises a sensor that has a light emitting device that emits light toward the inside of a storage chamber storing developer, and a light receiving device that receives the light emitted by the light emitting device, passing through the inside of the storage chamber, and going out, and sends a signal with an intensity according to the quantity of light received by the light receiving device. A sheet of a stirring member is configured to block an optical path of the light emitted from the light emitting device inside the storage chamber, once in one cycle in which the stirring member makes one revolution about a rotation axis. The image forming apparatus has phase detection means that detects the rotational phase of the stirring member with reference to a period in the one cycle during which the intensity of the signal from the sensor falls below a threshold continuously over the longest time span.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus for forming an image on a recording material. [Background technology]

[0002] In general, an electrophotographic image forming apparatus forms an image on a recording material by transferring a toner image formed on the surface of a photosensitive drum to the recording material. Known methods for replenishing a developer consumed in image formation include, for example, a process cartridge method and a toner replenishing method. In the process cartridge method, a photosensitive drum and a developing container are integrated as a process cartridge, and when the developer runs out, the process cartridge is replaced with a new one. On the other hand, in the toner replenishing method, when the toner runs out, new toner is replenished to the developing container without replacing components as in the process cartridge method. Patent Document 1 discloses a configuration of a toner replenishing method (hereinafter referred to as a direct toner replenishing method) in which a toner pack is attached to the developing container so that a part of the toner pack is exposed to the outside, and the toner contained in the toner pack is replenished into the developing container all at once, without replacing the process cartridge. In the configuration of Patent Document 1, the remaining amount of toner during consumption and the remaining amount of toner after replenishing can be detected by an optical toner remaining amount detection means, and the user can be notified. The optical toner remaining amount detection means is installed in the same chamber as the toner in the developing container, and grasps the amount of toner in the developing container based on the time the optical path is blocked by the toner in the developing container and the time it is not blocked. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-27631 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a technique capable of detecting the phase of an agitating member in a simple manner in an image forming apparatus having an optical remaining toner amount detection means. [Means for solving the problem]

[0005] In order to achieve the above object, an image forming apparatus according to the present invention comprises: An image carrier; a developer carrier that carries a developer for developing the electrostatic latent image formed on the image carrier; a frame having a developing chamber in which the developer carrier is disposed and a storage chamber communicating with the developing chamber and storing a developer; a stirring member provided inside the storage chamber, the stirring member having a rotating shaft rotatable around a rotation axis line, and a sheet having a first end, which is one end in the direction of the rotation axis line, fixed to the rotating shaft and a second end, which is the other end, being a free end, and stirring the developer by the sheet rotating together with the rotating shaft; a sensor including a light-emitting element that emits light toward the inside of the storage chamber, and a light-receiving element that receives the light emitted by the light-emitting element and that passes through the inside of the storage chamber and is emitted to the outside of the storage chamber, the sensor emitting a signal having an intensity corresponding to the amount of light received by the light-receiving element; Equipped with In an image forming apparatus, the sheet of the stirring member is configured to block an optical path of light emitted from the light emitting element in the interior of the accommodation chamber once during one period in which the stirring member rotates around the rotation axis, The signal strength is determined based on the period during which the signal strength is continuously below the threshold value for the longest time during the one period. The present invention is characterized by having a phase detection means for detecting the rotational phase of the stirring member. Effect of the Invention

[0006] According to the present invention, in an image forming apparatus having an optical remaining toner amount detection unit, the phase of the stirring member can be detected by a simple method. [Brief description of the drawings]

[0007] [Figure 1] Cross-sectional view of an image forming apparatus 1 according to a first embodiment of the present invention. [Diagram 2] FIG. 3 is a perspective view of the stirring member 34. [Diagram 3] FIG. 1 is a perspective view of an image forming apparatus 1. [Figure 4] A perspective view and a front view of the process cartridge 20 and the toner pack 40 [Diagram 5] FIG. 2 shows a toner remaining amount detection sensor 50. [Figure 6] FIG. 2 is a diagram showing an example of a circuit configuration of a toner remaining amount detection sensor 50. [Figure 7] Block diagram showing a control system of the image forming apparatus 1 [Figure 8] A diagram showing the voltage waveform at toner levels FULL and LOW [Figure 9] A cross-sectional view showing the voltage waveform when the toner level is low and the phase of the stirring member at each timing. [Figure 10] FIG. 13 shows voltage waveforms at each toner level. [Figure 11] Phase detection flow chart [Figure 12] FIG. 13 shows the phase of the stirring member 34 during replenishment and the state of toner mixing by subsequent stirring. [Figure 13] FIG. 13 shows the phase of the stirring member 34 during replenishment and the state of toner mixing by subsequent stirring. [Figure 14] 3 is a cross-sectional view of a developing container 32 according to a second embodiment of the present invention; [Figure 15] FIG. 13 is a diagram showing a voltage waveform in Example 2. [Figure 16] FIG. 13 is a perspective view of the stirring member 34 according to the third embodiment; [Figure 17] FIG. 13 shows a voltage waveform in Example 3. [Figure 18] FIG. 11 is a diagram showing voltage waveforms in other embodiments. [Figure 19] 3 is a cross-sectional view of a developing container 32 according to a third embodiment of the present invention; [Figure 20] FIG. 2 is a schematic plan view showing the optical path of a laser beam from an exposure unit; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] In the following examples, the embodiments of the present disclosure will be described by way of example. However, the configurations disclosed in the following examples, such as the functions, materials, shapes, and relative positions of the parts, are examples of forms related to the scope of the claims, and are not intended to limit the scope of the claims to the configurations disclosed in these examples. Furthermore, the problems solved by the configurations disclosed in the following examples or the actions or effects obtained from the disclosed configurations are not intended to limit the scope of the claims.

[0009] Example 1 Fig. 1 is a schematic cross-sectional view showing the configuration of an image forming apparatus 1 according to a first embodiment of the present invention. Fig. 3 is a perspective view of the image forming apparatus 1 according to the present 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.

[0010] FIG. 1(a) shows the image forming apparatus 1 installed on a horizontal surface, which is the normally assumed installation state of the image forming apparatus 1, and the directions on the paper in this figure are defined as follows. The up and down directions on the paper are the vertical direction (the direction of gravity), the up direction on the paper is called the up direction, and the down direction on the paper is called the down direction. The left direction on the paper is called the rear direction (the direction from the front side of the device to the rear side), and the right direction on the paper is called the front direction (the direction from the rear side of the device to the front side). In addition, the front direction on the paper (the direction perpendicular to the paper, from the back side of the paper to the front side of the paper) is called the left direction, and the back direction (the direction perpendicular to the paper, from the front side of the paper to the back side of the paper) is called the back direction. and are referred to as the right direction, respectively.

[0011] The image forming section 10 has a scanner unit 11, an electrophotographic process cartridge 20, and a transfer roller 12 that transfers a toner image formed on a photosensitive drum (image carrier) 21 of the process cartridge 20 onto a recording material.

[0012] The process cartridge 20 has a photosensitive drum 21, and a developing device 30 including a charging roller 22, a pre-exposure device 23, and a developing roller (developer carrier) 31, which are arranged around the photosensitive drum 21.

[0013] The photosensitive drum 21 is a cylindrically shaped photosensitive member. The photosensitive drum 21 of this embodiment has a photosensitive layer formed of a negatively charged organic photosensitive member on a drum-shaped base body formed of aluminum. The photosensitive drum 21 is rotated by a motor in a predetermined direction (clockwise direction in the figure) at a predetermined process speed.

[0014] The charging roller 22 comes into contact with the photosensitive drum 21 with a predetermined pressure to form a charging portion. A desired charging voltage is applied by a charging high-voltage power supply to uniformly charge the surface of the photosensitive drum 21 to a predetermined potential. In this embodiment, the photosensitive drum 21 is negatively charged by the charging roller 22. The pre-exposure device 23 neutralizes the surface potential of the photosensitive drum 21 before it enters the charging portion in order to generate a stable discharge in the charging portion.

[0015] The scanner unit (exposure means) 11 uses a polygon mirror to irradiate the photosensitive drum 21 with laser light corresponding to image information input from an external device, thereby scanning and exposing the surface of the photosensitive drum 21. This exposure forms an electrostatic latent image corresponding to the image information on the surface of the photosensitive drum 21. Note that the scanner unit 11 is not limited to a laser scanner device, and may be, for example, an LED exposure device having an LED array in which a plurality of LEDs are arranged along the longitudinal direction of the photosensitive drum 21.

[0016] The developing device 30 includes a developing container 32 (frame) in which a developer is contained, a developing roller 31 as a developer carrier that carries the developer, and a supply roller 33 capable of supplying the developer to the developing roller 31. The toner contained in the developing container 32 as the developer is applied to the surface of the developing roller 31 by the supply roller 33. The developing container 32 has a developing chamber 32e in which the developing roller 31 and the supply roller 33 are disposed, and a toner storage chamber (developer storage chamber) 32d that communicates with the developing chamber 32e and stores toner to be supplied to the developing chamber 32e. The developing container 32 has a convex portion (A in FIG. 1(a)) in the developing chamber 32e to hold the toner to be supplied to the developing roller 31 and the supply roller 33. The boundary portion between the toner storage chamber 32d and the developing chamber 32e at a position corresponding to the convex portion A is referred to as a developing opening 39. The supply roller 33 is not necessarily required as long as the supply roller 33 is configured to supply a sufficient amount of toner to the developing roller 31 .

[0017] The developing device 30 of this embodiment employs a contact developing method as a developing method, that is, the toner layer carried by the developing roller 31 comes into contact with the photosensitive drum 21 at a developing portion where the photosensitive drum 21 and the developing roller 31 face each other.

[0018] A developing voltage is applied to the developing roller 31 by a high-voltage developing power supply. Under the developing voltage, the toner carried by the developing roller 31 is transferred from the developing roller 31 to the surface of the photosensitive drum 21 in accordance with the potential distribution on the surface of the photosensitive drum 21, thereby developing the electrostatic latent image into a toner image. Note that in this embodiment, a reversal development method is adopted. That is, the toner image is formed by adhering to the surface area of ​​the photosensitive drum 21, which has been charged in the charging process and then exposed in the exposure process, where the charge amount has attenuated.

[0019] In this embodiment, a toner having a particle size of about 6 μm and a normal charging polarity of negative polarity is used. As an example of the toner in this embodiment, a polymerized toner produced by a polymerization method is used. The toner in this embodiment does not contain a magnetic component, and is a so-called non-magnetic one-component developer in which the toner is carried on the developing roller 31 mainly by intermolecular forces and electrostatic forces (image forces). However, a one-component developer containing a magnetic component may also be used. In addition to toner particles, the one-component developer may contain additives (e.g., wax or silica particles) for adjusting the fluidity and charging performance of the toner. A two-component developer composed of a non-magnetic toner and a magnetic carrier may also be used as the developer. When a magnetic developer is used, a cylindrical developing sleeve with a magnet arranged inside is used as the developer carrier.

[0020] The developing blade 35 regulates the amount of toner carried by the developing roller 31. The toner supplied to the surface of the developing roller 31 passes through the portion facing the developing blade 35 as the developing roller 31 rotates, whereby the toner is uniformly formed into a thin layer and is negatively charged by frictional charging.

[0021] Further, an agitator 34 is rotatably provided inside the toner storage chamber 32d of the developing container 32. Furthermore, a toner remaining amount detection sensor (developer remaining amount detection unit) 50 is provided on the inner wall of the toner storage chamber 32d as an optical detection means. The toner remaining amount detection sensor 50 has an optical path for detection light inside the toner storage chamber 32d, and detects the amount of toner stored in the toner storage chamber 32d based on the amount of detection light passing through the optical path. The configuration of the toner remaining amount detection sensor 50 will be described in detail later in the section on a method for detecting the amount of toner remaining.

[0022] 2 is a schematic perspective view showing the configuration of the agitating member. The agitating member 34 has an agitating shaft (rotating member) 34a extending in the longitudinal direction, a blade portion (first sheet) 34b extending radially outward from the agitating shaft 34a, and a cleaning member (second sheet) 34f extending radially outward from the agitating shaft 34a at a position different from the blade portion 34b. The cleaning member 34f is provided to clean the remaining toner amount detection sensor 50. In this embodiment, the cleaning member 34f is provided at a position 90° downstream of the blade portion 34b.

[0023] Specifically, the agitator shaft 34a has a first mounting surface 34a1 extending in the direction of the rotation axis, and a second mounting surface 34a2 extending in the direction of the rotation axis at a position around the rotation axis different from the first mounting surface 34a1. The first mounting surface 34a1 and the second mounting surface 34a2 are adjacent two of the four surfaces aligned in the rotation direction of the agitator shaft 34a having a rectangular cross section, and the directions in which the perpendicular lines (normal lines) extend are perpendicular to each other.

[0024] The blade portion (first sheet) 34b1 has an attachment portion (first attachment portion) 34b11 that contacts the first attachment surface 34a1. One end (first end) 34b1e1 of the blade portion 34b1 in a direction perpendicular to the rotation axis is fixed to the agitator shaft 34a as part of the attachment portion 34b11, and the other end (second end) 34b1e2 is a free end that can contact the inner wall surface of the toner storage chamber 32d.

[0025] The cleaning member (second sheet) 34f has an attachment portion (second attachment portion) 34f1 that contacts the second attachment surface 34a2. One end (third end) 34fe1 of the cleaning member 34f in a direction perpendicular to the rotation axis is fixed to the agitator shaft 34a as a part of the attachment portion 34f1, and the other end (fourth end) 34fe2 is capable of contacting the remaining toner amount detection sensor 50. More specifically, the cleaning member 34f is configured to be capable of contacting and cleaning the optical path surface of the remaining toner amount detection sensor 50 that forms an optical path of detection light inside the toner storage chamber 32d.

[0026] When viewed in the direction of the rotation axis of the agitator shaft 34a, the length of the blade portion 34b measured along the extension direction of the blade portion 34b from the attachment portion 34b1 to the end is longer than the length of the cleaning member 34f measured along the extension direction of the cleaning member 34f from the attachment portion 34f1 to the end. Also, in the longitudinal direction, which is the direction of the rotation axis of the agitator shaft 34a, the width of the cleaning member 34f is narrower than the width of the blade portion 34b. That is, the cleaning member 34f is provided only with a width corresponding to the longitudinal width of the remaining toner amount detection sensor 50, while the blade portion 34b is provided with a width corresponding to the longitudinal width of the toner storage chamber 32d. In addition, the longitudinal width of the blade portion 34b is narrower than the longitudinal width of the development opening 39, and the short length of the blade portion 34b (the length of the blade portion 34b measured along the extension direction of the blade portion 34b when viewed in the direction of the rotation axis) is a length that enables the blade portion 34b to enter the development chamber 32e through the development opening 39.

[0027] The stirring member 34 is rotated about the stirring shaft 34a by a motor via a gear 34c.

[0028] The blade portion 34b of the stirring member 34 in this embodiment is made of polycarbonate with a thickness of 180 μm and is flexible. It stirs the toner in the developing container 32 while bending and returning to its original shape following the shape of the inner wall of the developing container 32. Furthermore, the longitudinal width W of the blade portion 34b of the stirring member 34 is set narrower than the longitudinal width of the developing opening 39, so that it can enter the developing opening 39. The blade portion 34b also plays a role in sending the toner through the developing opening 39 toward the developing chamber 32e in which the developing roller 31 and the supply roller 33 are located.

[0029] In addition, the cleaning member 34f in this embodiment plays a role in preventing the toner remaining amount detection accuracy from being impaired due to toner falling on the toner remaining amount detection sensor 50 contaminating the optical path. The cleaning member 34f in this embodiment is made of a polyimide sheet with a thickness of 200 μm, which is highly abrasion resistant, so that it can fully withstand repeated rubbing against the optical path surface of the toner remaining amount detection sensor 50.

[0030] (Image formation operation) The image forming operation of the image forming apparatus 1 will be described with reference to FIG.

[0031] A print job is started when a command is input to the image forming apparatus 1. An image forming process P2 is executed by the image forming unit 10 based on image information input from an external computer or the like connected to the image forming apparatus 1. Generally, a pre-rotation process P1 as a preparation process for image formation and a post-rotation process P3 as a post-processing process are provided before and after the image forming process P2.

[0032] In the pre-rotation process P1, the scanner unit 11, various high voltage power supplies, and the fixing unit 70 are started up and stabilized. When each unit has started up, that is, when each unit is ready or expected to be ready to form an image, the pre-rotation process P1 ends and the image formation process P2 starts.

[0033] In the image forming process P2, the scanner unit 11 irradiates the photosensitive drum 21 with laser light L (see FIG. 1) 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 by irradiating it with the laser light L. Thereafter, the electrostatic latent image is developed by the developing roller 31, and a toner image is formed on the photosensitive drum 21.

[0034] In parallel with this image forming process, the feeding section 60 conveys the recording material P toward the transfer nip formed by the transfer roller 12 and the photosensitive drum 21. A transfer voltage is applied to the transfer roller 12 from a transfer high voltage power source, and the toner image carried on the photosensitive drum 21 is transferred onto the recording material P. is transcribed.

[0035] The recording material P onto which the toner image has been transferred is conveyed to the fixing unit 70, and the toner image is heated and pressurized when passing through a nip between a fixing film 71 and a pressure roller 72 of the fixing unit 70. This causes the toner particles to melt and then adhere to the recording material P, thereby fixing the toner image to the recording material P.

[0036] 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 a pair of discharge rollers 80 serving as a discharge means, and is stacked on a discharge tray 81 serving as a stacking unit formed on the upper part of the image forming apparatus 1. After all the designated recording materials have been discharged onto the discharge tray 81, the image forming apparatus 1 proceeds to a post-rotation process P3.

[0037] In the post-rotation process P3, various high-voltage power supplies are turned off, and the fixing unit 70 is rotated at a temperature lower than the temperature control during paper passage or with the temperature control turned off in order to equalize the temperature difference between the paper passing area and the non-paper passing area.

[0038] (Cleanerless toner collection) The toner (transfer residual toner) remaining on the photosensitive drum 21 without being transferred to the recording material P during the transfer step is removed from the photosensitive drum 21 in the following manner.

[0039] After the transfer process, the surface of the photosensitive drum 21 is neutralized by a pre-exposure device 23 so that the surface potential becomes 0 V, and then the photosensitive drum 21 enters a charging section. The residual toner remaining on the photosensitive drum 21 includes a mixture of positively charged toner and negatively charged toner that does not have a sufficient charge. This residual toner is charged negatively by discharge in the charging section.

[0040] The transfer residual toner, negatively charged in the charging portion, reaches a position facing the developing roller 31 as the photosensitive drum 21 rotates. Here, an electrostatic latent image corresponding to image information is formed on the surface of the photosensitive drum 21 that has reached the position facing the developing roller 31. The transfer residual toner adhering to the non-exposed portion (non-image portion) of the photosensitive drum 21 moves from the photosensitive drum 21 to the developing roller 31 at the portion facing the developing roller 31 due to the potential difference between the pre-exposure potential on the photosensitive drum 21 and the development voltage, and is collected in the developing chamber 32e of the developer container 32. The toner collected in the developing chamber 32e is used again for image formation.

[0041] On the other hand, the residual toner adhering to the exposed portion (image portion) on the photosensitive drum 21 does not move from the photosensitive drum 21 to the developing roller 31, but forms a toner image together with the toner that has moved from the developing roller 31 to the photosensitive drum 21. Then, this toner is transferred onto the recording material P at the transfer portion and removed from the photosensitive drum 21.

[0042] (Image forming device control system) 7 is a block diagram showing a control system of the image forming apparatus 1. A control unit 90 as a control means of the image forming apparatus 1 has a CPU 91 as a calculation device, a RAM 92 used as a working area for the CPU 91, and a ROM 93 for storing various programs. The control unit 90 also has an I / O interface 94 as an input / output port connected to an external device, and an A / D conversion unit 95 for converting an analog signal into a digital signal.

[0043] The input side of the control unit 90 is connected to the toner remaining amount detection sensor 50 .

[0044] The control unit 90 is also connected to an operation unit 300 and the image forming unit 10. The operation unit 300 has a display unit 301 capable of displaying various setting screens, physical keys, and the like. 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, the developing roller 31, the supply roller 33, the stirring member 34, etc. The photosensitive drum 21, the developing roller 31, the supply roller 33, and the stirring member 34 may be configured to be driven by separate motors, respectively.

[0045] (Configuration related to toner supply) A configuration related to toner supply will be described with reference to FIG. 3. FIG. 3 is a perspective view of the image forming apparatus 1 in this embodiment. As shown in FIG. 3, in this embodiment, which is a direct toner supply system, an opening / closing member 83 for supplying toner by a toner pack 40 (developer supply container) is provided in an openable / closable manner on a discharge tray 81. A main body side supply opening 82 that opens upward is formed on the discharge tray 81. The opening / closing member 83 is configured to be movable between a closed position that covers the supply port 32a (developer receiving port) so that the toner pack 40 cannot be attached to the developing container 32, and an open position that exposes the supply port 32a so that the toner pack 40 can be attached to the developing container 32. The opening / closing member 83 functions as a part of the discharge tray 81 in the closed position. The opening / closing member 83 and the main body side supply opening 82 are formed on the left side of the discharge tray 81.

[0046] The configurations of the developing container 32 and the toner pack 40 will be described with reference to Figures 4(a) and 4(b). Figure 4(a) is a perspective view showing the developing container 32 and the toner pack 40, and Figure 4(b) is a front view showing the developing container 32 and the toner pack 40.

[0047] The developing container 32 has a protruding portion 38 protruding from one end in the longitudinal direction toward the front and upward of the device. An attachment portion 57 to which the toner pack 40 can be attached is provided at the upper end (tip) of the protruding portion 38, and a supply port 32a is formed in the attachment portion 57 for supplying developer from the toner pack 40 to the developing container 32. The supply port 32a opens to the outside of the developing container 32 and communicates with an introduction port 32c (accommodation chamber opening) that opens on the inner wall of the toner storage chamber 32d of the developing container 32. That is, a toner supply path extending from the supply port 32a to the introduction port 32c is formed inside the protruding portion 38, and the supply port 32a and the introduction port 32c are configured to be able to communicate with each other. That is, in this embodiment, the attachment portion 57 having the supply port 32a is disposed on the front side of the image forming apparatus 1, making it easier for the user to supply toner to the developing container 32.

[0048] The toner pack 40 is configured to be detachably attached to a mounting portion 57 provided at the tip of the protruding portion 38 of the developing container 32. The toner pack 40 also has an openable and closable shutter member 41 provided at the opening, and a plurality of protrusions 42 formed in correspondence with the plurality of grooves 32b formed in the mounting portion 57. The shutter member 41 is configured to be movable between an open position that opens the opening, and a closed position that closes the opening.

[0049] When replenishing toner in the developing container 32, the user aligns the projection 42 of the toner pack 40 so that it passes through the groove 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 abutment portion (not shown) of the mounting portion 57, causing the toner pack 40 to rotate relative to the main body of the toner pack 40 and opening the shutter member 41. This causes the toner contained in the toner pack 40 to leak out of the toner pack 40, and the leaked toner enters the developing container 32 through the replenishing port 32a. The shutter member 41 may be provided on the replenishing port 32a side.

[0050] The toner supplied from the supply port 32a is sent toward the developing roller 31 and the supply roller 33 as the agitating member 34 in the developing container 32 rotates. The supply port 32a and the protruding portion 38 are disposed at one end of the developing container 32 in the longitudinal direction. By repeating this process, the toner spreads over the entire area of ​​the developing container 32 .

[0051] The positional relationship between the toner supply path of the developing container 32 and the scanner unit 11 will be described with reference to Fig. 20. Fig. 20 is a schematic plan view illustrating the positional relationship between the scanner unit 11 and the supply port 32a and the introduction port 32c of the developing container 32, and is a plan view along the scanning optical path of the laser light L of the scanner unit 11.

[0052] The scanner unit 11 includes a light source 110, an aperture 111, an incident optical element 112, a deflector 113, and an imaging optical element 114. The light source 110 is, for example, a semiconductor laser. The aperture 111 has an elliptical opening and limits the diameter of the light beam emitted from the light source 110 in each of the main scanning direction and the sub-scanning direction. The incident optical element 112 has a positive refractive power in the main scanning cross section, and converts the light beam that has passed through the aperture 111 into a parallel light beam in the main scanning cross section. In the scanner unit 11, the light beam that has passed through the aperture 111 is converted into a weakly convergent light beam, thereby reducing the refractive power required for the imaging optical element 114. The incident optical element 112 also has a positive refractive power in the sub-scanning cross section, and forms a long line image in the main scanning direction by concentrating the light beam that has passed through the aperture 111 near the deflection surface 113a of the deflector 113 in the sub-scanning cross section.

[0053] The imaging optical element 114 has positive refractive power in both the main scanning section and the sub-scanning section, and forms a spot-shaped image near the scanned surface of the photosensitive drum 21 by concentrating the light beam deflected by the deflector 113 in both the main scanning section and the sub-scanning section. Specifically, the imaging optical element 114 has two optical surfaces (lens surfaces), an entrance surface and an exit surface, and is configured so that the light beam deflected by the deflecting surface 113a of the deflector 113 scans the scanned surface of the photosensitive drum 21 with desired scanning characteristics in the main scanning section. In addition, the imaging optical element 114 compensates for surface tilt (i.e., reduces the scanning position deviation in the sub-scanning direction on the scanned surface of the photosensitive drum 21 when the deflecting surface 113a is tilted) by making the vicinity of the deflecting surface 113a of the deflector 113 and the vicinity of the scanned surface of the photosensitive drum 21 conjugate with each other in the sub-scanning section.

[0054] In this way, the light beam emitted from the light source 110 passes through the diaphragm 111 and the incident optical element 112, and then enters the deflection surface 113a of the deflector 113. Then, the light beam reflected and deflected by the deflection surface 113a of the deflector 113 is guided to the scanned surface of the photosensitive drum 21 by the imaging optical element 114. The deflector 113 is rotated at a constant speed by a driving unit (not shown), and optically scans the scanned surface of the photosensitive drum 21 in the main scanning direction indicated by the arrow D, thereby forming an electrostatic latent image on the scanned surface of the photosensitive drum 21.

[0055] 20 and 1, the protrusion 38 of the developing container 32 (the toner supply path from the supply port 32a to the introduction port 32c) extends above and below the scanning optical path of the laser light L of the scanner unit 11 at a position that avoids the scanning optical path of the laser light L. That is, when viewed in the left-right direction of the device, the supply port 32a is located above the scanning optical path of the laser light L, and the introduction port 32c is located below the scanning optical path of the laser light L. The left-right direction of the device is a direction approximately parallel to the rotation axis direction of rotating bodies such as the photosensitive drum 21, the developing roller 31, the supply roller 33, and the stirring member 34.

[0056] 20, the toner supply path from the supply port 32a to the introduction port 32c is located inside the end of the photosensitive drum 21 (toward the center of the photosensitive drum 21) in the left-right direction of the device. Also, it is located between the photosensitive drum 21 and the scanner unit 11 in the front-rear direction of the device. In other words, the protrusion 38 of the developing container 32 is disposed so as to avoid the scanning optical path of the laser light L emitted from the imaging optical element 114, and not to increase the size of the device in the left-right direction and the front-rear direction of the device.

[0057] (Configuration of remaining toner amount detection sensor 50 and method for detecting remaining toner amount) The configuration of the toner remaining amount detection sensor 50 and a method of detecting the remaining amount of toner will be described with reference to Figs. 5(a) to 5(c). Fig. 5(a) is a cross-sectional view of the B-B' surface from the rear side of the developing container 32 installed in the image forming apparatus 1 shown in Fig. 1. Figs. 5(a)(b) and 5(a)(c) are perspective views of the light guide 600. Fig. 6 is a circuit diagram showing an example of the circuit configuration of the toner remaining amount detection sensor 50, and Fig. 7 is a block diagram showing the control system of the image forming apparatus 1.

[0058] As shown in Figures 5(a) to 5(c), in this embodiment, a light guide 600 constituting the toner remaining amount detection sensor 50 is installed in the center of the longitudinal direction of the developing container 32. The light guide 600 has a light entrance section 611 that takes in light from the light emitting section 52 into the light guide 600 outside the developing container 32, optical path surfaces 612 and 622 that generate an optical path Q inside the developing container 32, and a light exit section 621 that delivers the light that has passed through the optical path Q inside the developing container 32 to the light receiving section 53. The light guide 600 is made of amorphous polystyrene that is highly transparent.

[0059] 6, the light-emitting unit 52 uses an LED as a light-emitting element, and the light-receiving unit 53 uses a phototransistor as a light-receiving element that is turned on by light from the LED. A switch (not shown) is provided between the light-emitting unit 52 and the power supply voltage Vcc, and by turning on the switch, a voltage from the power supply voltage Vcc is applied to the light-emitting unit 52, and the light-emitting unit 52 is brought into a conductive state. Meanwhile, a switch (not shown) is also provided between the light-receiving unit 53 and the power supply voltage Vcc, and by turning on the switch, the light-receiving unit 53 is brought into a conductive state by a current corresponding to the detected amount of light. For example, the light-emitting unit 52 may be a halogen lamp or a fluorescent lamp, and the light-receiving unit 53 may be a photodiode or an avalanche photodiode.

[0060] A power supply voltage Vcc and a current limiting resistor R1 are connected to the light-emitting unit 52, and the light-emitting unit 52 emits light with a current determined by the current limiting resistor R1. The light emitted from the light-emitting unit 52 passes through an optical path Q as shown in FIG. 5(b) and is received by the light-receiving unit 53. A power supply voltage Vcc is connected to the collector terminal of the light-receiving unit 53, and a detection resistor R2 is connected to the emitter terminal. The light-receiving unit 53, which is a phototransistor, receives the light emitted from the light-emitting unit 52 and transmits (outputs) a signal (current) with an intensity corresponding to the amount of light received. This signal is converted to a voltage V1 by the detection resistor R2 and input to an A / D conversion unit 95 of the control unit 90 (see FIG. 7).

[0061] The CPU 91 of the control unit 90 judges whether the light receiving unit 53 has received light from the light emitting unit 52 based on the input voltage level. The CPU 91 of the control unit 90 calculates the amount of toner (amount of developer) in the development container 32 based on the length of time that the light receiving unit 53 detected each light when the toner in the development container 32 was stirred for a certain time by the stirring member 34 and the intensity of the received light. That is, the ROM 93 stores in advance a table that can output the remaining toner amount from the light receiving time and light intensity when the toner is transported by the stirring member 34, and the control unit 90 predicts / calculates the remaining toner amount based on the input to the A / D conversion unit 95 and the table.

[0062] More specifically, the time during which the light path Q is blocked by the toner conveyed by the agitating member 34 when the agitating member 34 makes one rotation, i.e., the time during which the light receiving unit 53 does not detect the light from the light emitting unit 52, varies depending on the remaining amount of toner. Also, the intensity of the light received by the light receiving unit 53 varies depending on the remaining amount of toner.

[0063] In other words, when the remaining toner amount is low, the light receiving portion 53 receives more toner than when the remaining toner amount is high. The time that the light is received by the light-receiving portion 53 becomes longer, and the intensity of the light received by the light-receiving portion 53 also becomes stronger. The control portion 90 can determine the remaining toner level based on the time that the light is received by the light-receiving portion 53 and the intensity of the light received.

[0064] (Voltage waveform based on light receiving signal from light receiving unit 53 and remaining amount detection method) The toner remaining amount detection method in this embodiment will be described with reference to Figs. 8(a) and 8(b). Figs. 8(a) and 8(b) are diagrams showing a cross-sectional image of the developing container 32 immediately before the cleaning member 34f passes through the toner remaining amount detection sensor 50, and a waveform of a voltage value obtained by converting the light receiving signal of the light receiving unit 53 by the A / D conversion unit 95. Timing F of the voltage value waveform corresponds to the timing immediately before the cleaning member 34f passes through the toner remaining amount detection sensor 50 in the cross-sectional image. Fig. 8(a) shows a case where the toner level is FULL, which is a case where the toner amount in the developing container 32 is large, and Fig. 8(b) shows a case where the toner level is LOW, which is a case where the toner amount in the developing container 32 is small. The shaded portion in the cross-sectional image diagram typically shows the toner present in the developing container 32.

[0065] In this embodiment, the maximum voltage value after the light receiving signal of the light receiving unit 53 is converted into a voltage value by the A / D conversion unit 95 is 3.3V, the time during which a voltage of 1V or more is detected is the ON time, and the time (period) during which a voltage of less than 1V is detected is the OFF time (OFF period). A method is adopted in which the amount of remaining toner is determined based on the ratio of the ON time to the time Ta of one cycle of one rotation of the agitating member 34. In this embodiment, the time Ta of one cycle of one rotation of the agitating member 34 is 1.0 second. It is determined that the greater the ratio of the ON time, the less the amount of remaining toner, and the smaller the ratio of the ON time, the more the amount of remaining toner.

[0066] The toner level FULL shown in FIG. 8(a) is a state in which the amount of toner is large and the toner surface is always located at the upper part of the light guide 600 of the toner remaining amount detection sensor 50. Therefore, the light receiving portion 53 receives light and the ON time Tf1 occurs only when the cleaning member 34f cleans the optical path surfaces 612 and 622 of the light guide 600, but the OFF time occurs immediately after the cleaning member 34f passes. This is because the toner present around the light guide 600 of the toner remaining amount detection sensor 50 immediately blocks the optical path Q. In this embodiment, the ON time Tf1 is 0.1 to 0.2 seconds (arrow in the figure), and when the ON time during one cycle Ta time (1.0 second) is 0.1 to 0.2 seconds, the toner level is determined to be FULL.

[0067] The toner level LOW shown in FIG. 8(b) has a longer ON time than the toner level FULL because the amount of toner is small and the light guide 600 of the toner remaining amount detection sensor 50 is not blocked for a longer period of time. In this embodiment, the ON time at the toner level LOW is 0.6 to 0.7 seconds, which is the total time of Tlow1 to Tlow3 indicated by the arrows in the figure. On the other hand, the OFF time is formed by the timing when the cleaning member 34f passes, the timing when the toner conveyed by the stirring member 34 blocks the light guide 600 of the toner remaining amount detection sensor 50, and the like. The phase detection of the stirring member 34 in this embodiment is performed by reading these OFF times, and a specific method will be described later in the section "Voltage waveform based on the light receiving signal of the light receiving unit 53 and phase detection of the stirring member". In this embodiment, when the ON time during one rotation Ta time (1.0 second) is 0.6 to 0.7 seconds, the toner level is determined to be LOW.

[0068] (Voltage waveform based on light receiving signal of light receiving unit 53 and phase detection of stirring member) In this embodiment, the control unit 90 functions as a phase detection unit that detects the phase of the agitating member 34 based on the timing of an OFF period during which the amount of detection light of the toner remaining amount detection sensor 50 falls below a predetermined amount of light. The blade portion 34b of the agitating member 34 is configured to block the optical path of light emitted from the light-emitting element of the toner remaining amount detection sensor 50 inside the toner storage chamber 32d once during one period in which the agitating member 34 rotates around the rotation axis. The phase of the agitating member 34 is determined based on the amount of detection light of the toner remaining amount detection sensor 50 that occurs during one rotation of the agitating member 34. The rotation phase of the agitating member 34 can be detected based on the timing of the occurrence of the longest OFF period among a plurality of OFF periods during which the light intensity falls below a predetermined light intensity. Here, the longest OFF period is the period during which the intensity of the signal emitted by the light receiving element of the toner remaining amount detection sensor 50 falls below the threshold continuously for the longest period during one cycle of the agitating member 34. A plurality of periods during which the intensity of the signal emitted by the light receiving element falls below the threshold continuously are included during one cycle of the agitating member 34. The rotation phase of the agitating member 34 can be detected based on the end timing of the first period during which the intensity of the signal emitted by the light receiving element falls below the threshold for the longest period among the plurality of periods. Note that when the remaining toner amount is large, only one second period during which the intensity of the signal of the light receiving element exceeds the threshold may be included, and the remaining period may be a period during which the intensity of the signal falls below the threshold. In such a case, the rotation phase of the agitating member 34 can be detected based on the start timing of the second period during which the signal intensity exceeds the threshold.

[0069] The longest OFF period includes a period during which the blade portion 34b of the stirring member 34 blocks the optical path of the detection light of the remaining toner amount detection sensor 50. In other words, the multiple OFF periods include, for example, an OFF period (second OFF period) including a period during which the cleaning member 34f blocks the optical path of the detection light, but the OFF period (first OFF period) including a period during which the blade portion 34b blocks the optical path of the detection light is longer than this OFF period.

[0070] 9(a) to 9(e), the details of the change timing of each voltage value waveform and a specific phase detection method for the agitating member 34 in this embodiment will be described. In this embodiment, the phase of the agitating member 34 is detected based on the voltage value waveform for determining the remaining toner level as described above. The phase detection method of this embodiment is characterized in that the voltage waveform based on the light receiving signal of the light receiving unit 53 has an OFF time Toffa that is longer than the OFF time Toff1 at the timing when the cleaning member 34f passes and the short noise-like Toff2 that occurs in 0.1 seconds or less.

[0071] 9(b) to 9(e) show, as an example, voltage waveforms and cross-sectional image diagrams when the toner level is LOW. The shaded areas in the cross-sectional image diagrams represent the toner present in the developer container 32. Details of the change timing of the voltage waveform for other toner remaining levels will be described later in the section "Toffa detection and phase for other remaining toner amounts."

[0072] FIG. 9(a) shows a voltage waveform based on a light receiving signal from the light receiving section 53, and FIGS. 9(b) to 9(f) show the state of the toner in the developing container 32 at each timing when the light receiving signal changes.

[0073] FIG. 9(b) shows the state immediately before the cleaning member 34f cleans the light guide 600. The voltage waveform corresponds to timing Tposition1. As shown in FIG. 9(b), at the toner level LOW, the amount of toner is small and the light guide 600 is not shaded by the toner, so the voltage waveform is in the ON state (Ton1). When the cleaning member 34f passes by, the light is shaded by the cleaning member 34f itself, causing a momentary (0.1 second or less) Toff time (Toff1). The ON time continues until timing Tposition2 when the toner next shades the light guide 600 (Ton2).

[0074] Fig. 9(c) shows the timing when the rotation of the vane portion 34b progresses from the state in Fig. 9(b), and the toner carried by the vane portion 34b falls downward by gravity and passes through the light guide 600. In the voltage waveform, this corresponds to timing Tposition3. The timing and amount of toner that starts to slide down differs each time. For example, the light guide 600 may be blocked for an instant (0.1 seconds or less) and detected as 0FF time (Toff2), or the toner may not completely block the light guide 600 and may be detected as ON time.

[0075] FIG. 9(d) shows that the toner on the blade portion 34b has fallen off and most of the toner in the developing container 32 has disappeared. This shows the timing when most of the toner in the developing container 32 is at the bottom. In the voltage waveform, this corresponds to timing Tposition4. With a toner amount at toner level LOW, even when most of the toner in the developing container 32 is at the bottom, the toner surface is located below the light guide 600 and does not block the light guide 600. Therefore, the ON time continues (Ton3).

[0076] 9(e) shows the timing when the blade portion 34b digs into the toner surface, raising the toner surface and blocking the light guide 600 with toner. In the voltage waveform, this corresponds to timing T(e). The OFF time (Toffa) that occurs at this timing is not a momentary noise-like OFF time of less than 0.1 seconds like Toff1 and Toff2, but is the longest OFF time during one rotation of the blade portion 34b.

[0077] Here, the longest OFF time during one rotation of the stirring member 34 is defined as the Toffa time. In this embodiment, the Toffa time is about 0.2 to 0.4 seconds for the toner amount at the toner level LOW. Note that this Toffa time varies depending on the toner amount. The case of other toner amounts will be described later.

[0078] Finally, when the blade portion 34b passes through the light guide 600 and starts to send the toner at the bottom of the developing container 32 to the developing opening 39, the toner that was blocking the light guide 600 falls to the bottom of the developing container 32, and there is nothing blocking the light guide 600. Therefore, the OFF time Toffa ends and the ON time is resumed (Ton1). The state of FIG. 9(b) where the cleaning member 34f passes again is returned to and the process is repeated.

[0079] Here, Toff1, which occurs when the cleaning member 34f cleans the light guide 600, is a voltage change that occurs when the cleaning member 34f passes through, and occurs every cycle. Therefore, it may be possible to detect the phase of the agitating member 34 based on the timing when the cleaning member 34f passes through the light guide 600, depending on the configuration in the developing container and the amount of toner remaining. However, Toff1, which occurs when the cleaning member 34f cleans the light guide 600, is difficult to distinguish from OFF times that occur as noise, such as Toff2, which is caused by light blocking when the toner on the blade portion 34b falls onto the light guide 600, and a momentary OFF time caused by the toner flying around in the developing container 32 due to the impact of the toner falling to the bottom of the developing container 32 during the transition from the state shown in FIG. 9(c) to the state shown in FIG. 9(d).

[0080] Therefore, in this embodiment, the OFF time Toffa from before the blade portion 34b passes through the light guide 600 to immediately after the blade portion 34b passes through is used to detect the phase of the agitating member 34 as a longer OFF time that is easily distinguished from the OFF time generated as noise. As described above, the OFF time Toffa from before the blade portion 34b passes through the light guide 600 to immediately after the blade portion 34b passes through the light guide 600 is the time from the timing when the blade portion 34b bites into the toner agent surface and raises the toner agent surface, thereby blocking the light guide 600 with toner, to the timing when the blade portion 34b passes through the light guide 600. Toffa is longer than Toff1 and Toff2, and the OFF time is formed stably every rotation, so that the phase of the agitating member 34 can be stably detected. In this way, the phase of the blade portion 34b can be detected by detecting the longest OFF time Toffa during one rotation of the agitating member 34 from the voltage waveform based on the received signal from the light receiving unit 53.

[0081] (Toffa detection and phase when other toner levels remain) 10(a) to 10(d) show voltage waveforms based on signals received from the light receiving unit 53 at various toner levels corresponding to various remaining toner amounts, and cross-sectional views of the inside of the developing container 32 before the vane portion 34b passes through the light guide 600 (timing X in the voltage waveform diagram). FIG. 10(a) shows a toner level of FULL, FIG. 10(b) shows a toner level of HALF FULL, and FIG. FIG. 10(c) shows the voltage waveform of the toner level LOW, and FIG. 10(d) shows the voltage waveform of the toner level OUT. In this embodiment, the toner level OUT does not mean a state where the toner is completely depleted, but means a remaining amount where the toner is deformed or additives are embedded in the toner due to repeated image forming processes, and even if the charging performance is reduced, image defects such as fogging are unlikely to occur. The toner level FULL corresponds to the amount of toner at the maximum capacity of the developing container 32. The toner level HALFFULL corresponds to the amount of toner when half of the amount obtained by subtracting the toner level OUT from the toner level FULL has been consumed. The toner level LOW corresponds to the amount obtained by subtracting the toner level OUT from the toner level FULL, that is, when 95% of the amount obtained by subtracting the toner level OUT from the toner level FULL has been consumed, that is, the remaining 5% of the toner amount.

[0082] Table 1 also lists the OFF times occurring during one revolution Ta of the stirring member at each toner level.

[0083] Table 1. List of OFF times for each toner level TIFF2025035532000002.tif22153

[0084] 10A, the toner level FULL is a state in which the amount of toner is large and the toner surface is always located at the upper part of the light guide 600. Therefore, the light receiving portion 53 receives light and the ON time Tf1 occurs only when the cleaning member 34f cleans the optical path surfaces 612 and 622 of the light guide 600, but after the cleaning member 34f passes, the toner present around the light guide 600 immediately blocks the optical path Q, resulting in the OFF time.

[0085] In this embodiment, the longest OFF time Toffa(FULL) during one revolution of the agitator 34 at the toner level FULL was 0.8 to 0.9 seconds. When Toffa is 0.8 seconds or more during one revolution time Ta of 1.0 seconds of the agitator 34, it can be determined that the only ON time during one revolution is the timing F of cleaning. It can be determined that the timing F of this ON time is the timing when the cleaning member 34f passed through the light guide 600.

[0086] In the toner level HALFFULL of FIG. 10(b), when most of the toner is present at the bottom of the developing container 32, the toner agent surface is located at the top of the light guide 600. However, when the vane portion 34b sends the toner at the bottom to the developing opening 39, there is little toner blocking the light guide 600. Therefore, the ON time Thf1 occurs at the timing when the vane portion 34b sends the toner to the developing opening 39. After that, the cleaning member 34f passes through the light guide 600, so the cleaning member 34f momentarily blocks the light guide 600, and the OFF time Thf2 is detected, but it immediately returns to the ON time.

[0087] Next, the OFF time Thf3 is detected when the toner on the blade portion 34b falls to the bottom of the developing container 32 while blocking the optical path Q of the light guide 600. After the toner falls to the bottom, there may be no more toner blocking the optical path Q while it is falling, forming the ON time Thf4, or there may be cases where the toner that has landed on the bottom causes the light to be blocked continuously by the toner, etc.

[0088] When the toner falls to the bottom of the developing container 32, the toner surface becomes higher than the light guide 600, and the toner blocks the light guide 600, resulting in the OFF time. The OFF time Toffa (HALFFULL) is formed until just before the vane portion 34b passes through the light guide 600. When the toner starts to be sent out to the developing opening 39, the amount of toner blocking the light guide 600 becomes small, and the ON time becomes Thf1.

[0089] In this embodiment, the longest OFF time Toffa(HALFFULL) during one revolution of the agitator 34 at the toner level HALFULL was 0.5 seconds. However, if Thf4 does not occur and the OFF time of Thf3 continues, Toffa(HALFFULL) occurs from Thf3 onwards, and the longest OFF time Toffa(HALFFULL) during one revolution of the agitator 34 at the toner level HALFULL in this embodiment is 0.7 seconds. The phase of the agitator 34 does not depend on the length of Toffa, and it can be determined that the timing A at which the OFF time Toffa switches to ON is the timing at which the blade portion 34b passes through the light guide 600.

[0090] 10(c) is as described above, so a detailed description will be omitted. As with the toner level HALFULL, the OFF time Toffa is formed from before the vane portion 34b passes through the light guide 600 to immediately after it passes through. However, compared to the toner level HALFFULL, the timing at which the vane portion 34b starts to block the light guide 600 with toner by raising the toner agent surface is later, so Toffa(LOW) is shorter than Toffa(HALFFULL).

[0091] In this embodiment, the longest OFF time Toffa(LOW) during one revolution of the agitating member 34 at the toner level LOW is 0.25 seconds. The phase of the agitating member 34 can be determined as the timing A at which the OFF time Toffa(LOW) switches to ON, which is the timing at which the blade portion 34b passes through the light guide 600.

[0092] 10(d), even when most of the toner in the developing container 32 is present at the bottom, the toner level is located below the light guide 600 and does not block the light guide 600. When the blade portion 34b has sent the toner at the bottom to the developing opening 39, there is little toner blocking the light guide 600, so the ON time is Tout1, similar to the toner level HALFFULL and toner level LOW. When the cleaning member 34f momentarily blocks the light guide 600, the OFF time Tout2 is detected, but it immediately returns to the ON time.

[0093] Next, the light guide 600 is blocked at the timing when the toner on the blade portion 34b falls, and the OFF time Tout3 is detected. Since the overall toner amount is small, the amount of toner on the blade portion 34b is also small, and the timing of falling is later than the toner level HALFFULL and toner level LOW. Also, this timing may not completely block the light guide 600 and may not be the OFF time. Until all the toner falls to the bottom of the developing container 32, the toner floating in the developing container 32 may momentarily block the light guide 600, but the ON time Tout4 continues most of the time. Even after the toner falls to the bottom of the developing container 32, the toner agent surface is below the light guide 600 at the toner level OUT, so the ON time Tout4 continues.

[0094] In this embodiment, thereafter, there is a time Toffa during which the vane portion 34b raises the toner agent surface and blocks the light guide 600. When the vane portion 34b passes through the light guide 600 and starts to send the toner at the bottom of the developing container 32 to the developing opening 39, the amount of toner blocking the light guide 600 becomes small, and the ON time becomes Tout1.

[0095] In this embodiment, the longest OFF time Toffa(OUT) during one revolution of the stirring member 34 at the toner level HALFULL was 0.2 seconds. This can be judged as the timing when the vehicle passed No. 600.

[0096] (Sequence diagram of Toffa detection and mixing member 34 phase determination) FIG. 11 shows an example of a sequence for detecting Toffa and determining the phase of the stirring member 34 in this embodiment.

[0097] In step S1, a print job is started. In step S2, one second is waited for the speed of the drive motor to stabilize. Note that the time for waiting for the speed of the drive motor to stabilize does not have to be one second.

[0098] In S3 and S4, the timing when the OFF time begins is detected while the ON time and OFF time are repeated. In S3, when the drive motor becomes stable and the voltage value (hereinafter referred to as voltage value) after the light receiving signal of the light receiving unit 53 is converted into a voltage value by the A / D conversion unit 95 is less than 1V and the OFF time is in progress, the process waits for the next time when the voltage becomes 1V or more and the ON time is in progress. When the voltage value is 1V or more and the ON time is in progress or when the ON time is in progress, the process proceeds to S4. In S4, the next time when the voltage value becomes less than 1V and the OFF time is detected is detected, and the process proceeds to S5.

[0099] In S5, the time Toff during which the OFF period continues is stored in the CPU 91 of the control unit 90. This is performed for a time period of 2Ta, which is equivalent to two revolutions of the stirring member 34. The longest Toff time during the 2Ta period is stored in the CPU 91 as Toffa.

[0100] In S6 and S7, the phase of the stirring member 34 is determined as follows according to the time Toffa. In this embodiment, Ta is 1.0 second, and if Toffa is 0.8 seconds or more, it can be determined that the only ON time during one rotation is the timing F of cleaning. Therefore, when Toffa is 0.8 seconds or more in S6, the process moves to S7, and the ON timing at which Toffa ends is determined to be the timing at which the cleaning member 34f passes through the light guide 600. If Toffa is less than 0.8 seconds, the process moves to S8. The OFF time Toffa of less than 0.8 seconds refers to the period from before the blade portion 34b passes through the light guide 600 to immediately after it passes through, and the ON timing at which Toffa ends is determined to be the timing at which the blade portion 34b passes through the light guide 600.

[0101] (Phase control of the stirring member and toner remaining amount detection performance when replenishing new toner) 12(a) to 13(d), an example of the purpose of performing phase detection will be described, which is to shorten the time required for detecting and judging the remaining toner amount. Specifically, by controlling the phase of the stirring member 34 when toner is replenished from the toner pack 40, the mixed state of the toner replenished from the toner pack 40 (hereinafter, new toner) and the toner existing in the developing container 32 before the replenishment (hereinafter, old toner) can be made more uniform more quickly.

[0102] The toner may be continuously stirred in the developing container 32, or may become deformed or have additives embedded in it due to repeated image forming processes, particularly in the case of a cleanerless configuration as in this embodiment. Therefore, the charging performance of the old toner tends to be lower than that of the new toner.

[0103] On the other hand, surfaces 612, 622 of the light guide 600 on the inside of the developing container 32 are charged by repeated rubbing with the toner and the stirring member 34. For this reason, new toner with higher charging performance is more likely to adhere to the surfaces 612, 622 of the light guide 600, and the surfaces 612, 622 of the light guide 600 are always in a state of being blocked by the toner, which tends to reduce the accuracy of detecting the remaining toner amount.

[0104] Therefore, if the mixture of the old toner and the new toner after replenishment in the developing container 32 is not uniform, However, there are cases where the toner is likely to adhere to surfaces 612 and 622 of light guide 600 due to the portions where a large amount of new toner is unevenly present, resulting in a decrease in the accuracy of remaining toner detection.

[0105] However, when the mixture of the old toner and the new toner after replenishment in the developing container 32 becomes uniform, there is no part where the new toner is unevenly distributed, and the concentration of the new toner relative to the total toner amount can be made low overall. Therefore, the adhesion of the new toner to the surfaces 612 and 622 of the light guide 600 can be suppressed.

[0106] In other words, if the new toner after replenishment is mixed uniformly with the old toner in the developing container, the deterioration of the remaining toner amount detection accuracy can be suppressed.

[0107] 12(a) to 13(d) show images of the new toner (hatched area) supplied from toner pack 40 and the old toner (filled in area) in developing container 32 in this embodiment, as viewed from the cross section side and from the front side. These show how the new toner is actually inserted, as viewed from the front side, by preparing a transparent developing container and using yellow toner as the new toner in toner pack 40 and black toner as the old toner in the transparent developing container 32.

[0108] "Immediately after replenishment" here means before the agitator 34 starts to rotate. The image diagrams viewed from the front also show the state immediately after replenishment, 5 seconds after the agitator 34 starts to rotate (after 5 rotations of the agitator 34), and 20 seconds after (after 20 rotations of the agitator 34). The solid areas indicate areas where the proportion of old toner is high, the shaded areas indicate areas where the proportion of new toner is high, and the dotted areas indicate areas where the new toner and old toner are well mixed together.

[0109] Figures 12(a) to 12(d) show the case where new toner is supplied when the tip position of blade portion 34b of agitating member 34 at the time of supply is located at the farthest position from inlet 32c. Figures 13(a) to 13(d) show the case where new toner is supplied when the tip position of blade portion 34b of agitating member 34 at the time of supply is located on the inlet 32c side.

[0110] As shown in Figures 12(a) to 12(d), when the tip of the blade portion 34b is located at the farthest position from the inlet 32c during the supply of new toner, the new toner is discharged into a sufficiently wide space. Then, as the new toner falls to the bottom surface of the developing container 32, it spreads out in the longitudinal direction as if it were collapsing into a mountain. In other words, the supplied new toner is distributed throughout the longitudinal direction. This is because the old toner in the developing container 32 is pushed toward the developing opening 39, so there is almost no old toner on the bottom surface of the developing container 32, and a wide space is seen from the inlet 32c.

[0111] However, on the other hand, as shown in Figures 13(a) to 13(d), if the tip position of the blade portion 34b is positioned on the side of the inlet 32c when new toner is replenished, the new toner is ejected all at once into a narrow space, and the new toner ends up remaining directly below the supply port 32a in the toner supply path that runs from the supply port 32a inside the protrusion 38 to the inlet 32c.

[0112] As shown in Figures 13(a) to 13(d), when new toner remained in the vicinity of the inlet 32c in the longitudinal direction inside the developing container 32, even if the agitating member 34 was driven, it took more than 20 seconds (20 rotations of the agitating member 34) for the new toner to spread throughout the entire longitudinal area.

[0113] 13(a) to 13(d), after 5 seconds (5 rotations of the agitator 34), the new toner is still stuck on the inlet 32c side, and there is a portion where the proportion of new toner is high (waved line portion). When the ratio of new toner is high in some areas, the new toner adheres to the inner surfaces 612 and 622 of the developing container 32 of the light guide 600, lowering the accuracy of remaining toner detection. It is necessary to detect the remaining toner after 20 seconds or more have elapsed, which allows the new toner to permeate the entire longitudinal area, and this makes the user wait until the image forming apparatus 1 becomes usable after the new toner is replenished.

[0114] 12(a) to 12(d), in order to ensure that toner is replenished when the tip of the blade portion 34b is located at the farthest position from the inlet 32c, in this embodiment, the phase of the agitating member 34 is controlled as follows: That is, the phase of the agitating member 34 (blade portion 34b) is detected from a voltage waveform based on a signal received by the light receiving portion 53 of the remaining toner amount detection sensor 50, and the phase of the agitating member 34 (blade portion 34b) at the timing before replenishment is controlled.

[0115] 12(a) to 12(d), the new toner instantly spreads in the longitudinal direction inside the developing container 32 immediately after replenishment, and the new toner and old toner become uniform in about 5 seconds (5 rotations of the stirring member 34). Even at the 5-second mark, the phenomenon of new toner adhering to the light guide 600 can be suppressed, and the accuracy of remaining toner detection is unlikely to decrease, so it is possible to shorten the time the user has to wait after replenishment.

[0116] (Effects of this embodiment) According to this embodiment, in the waveform of the optical detection signal of the toner remaining amount detection sensor 50, an OFF time Toffa is provided that is longer than the OFF time when the cleaning member 34f passes and the OFF time generated as noise, and thus the phase of the agitating member 34 can be grasped.

[0117] In this embodiment, the OFF time Toffa starts when the blade portion 34b digs into the toner surface, raising the toner surface and blocking the light guide 600 with the toner. The OFF time Toffa continues until just after the blade portion 34b passes the light guide 600. The Toffa time is longer than the OFF time that occurs as noise, and the OFF time is formed stably with each rotation, so that the phase of the agitating member 34 can be detected stably.

[0118] By knowing the phase of the stirring member 34, the following becomes possible, for example.

[0119] For example, when new toner is replenished from the toner pack 40, the tip of the blade portion 34b is replenished when it is located at the farthest position from the inlet 32c. By replenishment when the tip of the blade portion 34b is located at the farthest position from the inlet 32c, the new toner instantly spreads in the longitudinal direction inside the developing container 32 immediately after replenishment, which has the effect of shortening the time required for uniform mixing of the new toner and the old toner. By making the mixture state of the new toner and the old toner uniform, the phenomenon of the new toner adhering to the light guide 600 can be suppressed, and the deterioration of the remaining toner detection accuracy can be suppressed. It becomes possible to detect the remaining toner amount without making the user wait after replenishment.

[0120] For example, the cleaning member 34f is prevented from being stopped for a long period of time in a state where it is in contact with the light guide 600. If the cleaning member 34f is left in contact with the light guide 600 for a long period of time, it is conceivable that the shape of the cleaning member 34f may become deformed over time and become hardened in a deformed state. Such a deformed cleaning member 34f may have poor cleaning ability, or toner that has gotten in between the cleaning member 34f and the light guide 600 may become stuck to the light guide 600, resulting in a decrease in the accuracy of remaining amount detection. By stopping the motor drive at a position where the cleaning member 34f is not in contact with the light guide 600, the decrease in remaining amount detection accuracy can be prevented. To suppress.

[0121] As described above, according to this embodiment, the phase of the stirring member 34 can be accurately grasped, so that the phase at which the motor drive is stopped can be freely selected.

[0122] In addition, in this embodiment, the result of detecting the phase of the stirring member 34 may be reflected in the stop position of the motor drive, and the control of the image forming apparatus may be changed depending on the phase of the stirring member 34 at the time of stopping. For example, when new toner is replenished when the tip position of the blade portion 34b is located near the inlet 32c, it takes longer to uniformly mix the new toner and the old toner than when the toner is replenished at other positions, and the accuracy of the toner remaining amount detection may decrease. Therefore, when the toner is replenished when the tip position of the blade portion 34b is located near the inlet 32c, it is preferable to adjust the timing of the toner remaining amount detection judgment. That is, the time Tk required for the new toner and the old toner to be uniformly mixed may be obtained in advance, and the timing of the toner remaining amount detection judgment may be set to after the time Tk has elapsed after the replenishment.

[0123] In addition, when it is detected that the cleaning member 34f is stopped in contact with the light guide 600, the conversion formula between the voltage value based on the light receiving signal of the light receiving unit 53 and the toner remaining amount detection judgment may be adjusted in anticipation of the possibility that the cleaning member 34f may be deformed or the light guide 600 may remain contaminated with toner for a while.

[0124] (others) Another possible reason why it takes time for new toner to mix with old toner is the relationship between the size of the toner storage chamber 32d of the developing container 32 and the size of the toner path of the protruding portion 38 (the size of the inlet 32c that opens into the inner wall surface of the toner storage chamber 32d). This problem is likely to occur when the width of the protruding portion 38 (inlet 32c) is small compared to the overall longitudinal length of the toner storage chamber 32d.

[0125] In this embodiment, in consideration of usability, the toner can be replenished from the top of the device, and the replenishment port does not block the laser light for exposure, and the inlet 32c is opened at a position offset toward one longitudinal end of the toner storage chamber 32d, as described above. In this embodiment, the longitudinal length of the toner storage chamber 32d is 230 mm, the longitudinal width (inner diameter) of the inlet 32c is 40 mm, and the length from the longitudinal center of the toner storage chamber 32d to the width center of the inlet 32c is 86 mm. Regarding the longitudinal position of the inlet 32c relative to the toner storage chamber 32d, even if the inlet 32c is opened at the longitudinal center of the toner storage chamber 32d, there is a concern that new toner may not reach both longitudinal ends easily depending on the phase of the stirring member 34. In other words, the configuration in which the above problem may occur is not limited to the above configuration shown in this embodiment.

[0126] In addition, if the toner storage chamber 32d has a sufficient width (height direction) and a sufficient distance can be provided between the tip of the blade portion 34b and the inlet 32c even when the tip of the blade portion 34b is located in the first quadrant, that is, if there is a space for the new toner to spread out in the longitudinal direction outside the orbit of the stirring member 34 (the tip of the blade portion 34b), the problem of the time required for mixing the new toner and the old toner described above is unlikely to occur. However, in order to provide such a space, it is necessary to increase the vertical width of the toner storage chamber 32d, and there is a concern that the size of the device body will become large. In the developing container 32 of this embodiment, the inlet 32c is opened at the same height as the area where the tip of the blade portion 34b can contact on the upper surface of the inner wall surface of the toner storage chamber 32d, so that the size of the device body does not become large in the vertical direction of the device. In other words, according to this embodiment, in a compact developing container 32 configuration in which there is not enough distance between the tip of the blade portion 34b of the stirring member 34 located in the first quadrant and the inlet 32c, it is possible to reduce the time required to mix new toner and old toner.

[0127] Example 2 Next, a second embodiment of the present invention will be described. Fig. 14(a) to Fig. 14(c) are cross-sectional views of the developing container 32 in the second embodiment. In the second embodiment, a T-seal 34g (indicated by a broken line in the figure) is provided as a sheet member that rotates following the blade portion 34b and is longer and softer in the radial direction than the blade portion 34b. By providing this T-seal 34g, the longest Toffa during one revolution (Ta time) of the stirring member 34 can be made longer than when the T-seal 34g is not provided. It is possible to obtain a system that can further increase the contrast with the OFF time that occurs in a noise-like manner of 0.1 seconds or less and can stably detect the phase of the stirring member 34 with high noise resistance.

[0128] The configuration other than the provision of the T-seal 34g is the same as that of the image forming apparatus described in the first embodiment, and a description of the common configuration will be omitted.

[0129] In this embodiment, the T-seal 34g of the second embodiment also serves as a sealing member for covering the development opening 39 and sealing the toner in the toner storage chamber so that toner does not leak during transportation of an unused image forming apparatus 1.

[0130] The T seal (third sheet) 34g is attached to the agitator shaft 34a so as to be overlapped with the blade portion 34b. One end (fifth end) of the T seal (third sheet) 34g in the direction of the rotation axis is included in the attachment portion (third attachment portion) 34g1 attached to the agitator shaft 34a, and the other end (sixth end) is adhered to the inner wall of the toner storage chamber 32d so as to seal the development opening 39 when the image forming apparatus or the developing container 32 is new. When viewed in the direction of the rotation axis of the agitator shaft 34a (longitudinal direction), the short side length of the T seal 34g measured along the extension direction of the T seal 34g from the attachment portion 34g1 from one end to the other end is longer than the length of the blade portion 34b. Also, the longitudinal width of the T seal 34g is wider than the longitudinal width of the blade portion 34b.

[0131] The T-seal 34g is, for example, a PET sheet having a thickness of about 45 um, on which an easy-peel film made of multi-layered polystyrene is laminated. For example, the easy-peel film may be AE300 manufactured by Sumika Plastec Co., Ltd.

[0132] FIG. 14(a) is a schematic cross-sectional view of the developer container 32 in an unused image forming apparatus 1. The T-seal 34g is wider in the longitudinal direction than the developer opening 39, and in an unused image forming apparatus 1, the T-seal 34g completely covers the developer opening 39 with its easy-peel side, sealing it so that the toner in the developer container 32 does not leak out to the developer roller 31 or the supply roller 33. The T-seal 34g is attached to the stirring shaft 34a of the stirring member 34, and when the image forming apparatus 1 is turned on for the first time at the user's site and the motor starts to rotate, the T-seal 34g is peeled off from the developer opening 39 in a winding manner by the rotation of the stirring shaft 34a. In this state, it is attached to the stirring shaft 34a of the stirring member 34 and rotates together with the blade portion 34b.

[0133] 14(b) is a schematic cross-sectional view of the developing container 32 immediately before the tip of the wing portion 34b passes through the light guide 600 when the toner in the developing container 32 is low near the toner level LOW. When the wing portion 34b enters the toner surface, a raised portion (Y portion in the figure) of the toner surface is generated.

[0134] FIG. 14(c) is a schematic cross-sectional view of the developing container 32 just after the tip of the blade portion 34b passes through the light guide 600, going further from the state shown in FIG. 14(b). The toner in the Y portion shown in FIG. 14(b) is not transported by the blade portion 34b, and falls toward the bottom of the developing container 32 by gravity. However, in the second embodiment, since the configuration has the T-seal 34g, the T-seal 34g acts as a support and blocks the optical path of the light guide 600 as toner Y'. Therefore, Due to the toner Y′, the OFF time continues even after the blade portion 34b has passed the light guide 600.

[0135] FIG. 15(a) is a voltage waveform based on the light receiving signal of the light receiving unit 53 in Example 2. For comparison, FIG. 15(b) shows the voltage waveform in Example 1. The longest OFF time Toffa' during one revolution (Ta time) of the stirring member 34 in Example 2 is longer than Toffa in Example 1. In Example 1, after the timing A when the blade portion 34b passes through the light guide 600, the toner that blocks the light guide 600 disappears, and the ON time is reached. However, in Example 2, even after the blade portion 34b passes through the light guide 600, the toner Y that blocks the light guide 600 exists due to the installation of the T seal 34g, and the OFF time continues. In other words, in Example 2, the OFF time continues until the timing A', which is slightly later than the timing A when the blade portion 34b passes through the light guide 600, and the Toffa' time becomes longer. In the second embodiment, the longest continuous OFF time Toffa' during one revolution of the stirring member 34 at the toner level LOW was 0.3 seconds.

[0136] Even in the case of this embodiment where the optical path of the light guide 600 is blocked multiple times during one revolution of the agitating member 34 by the cleaning member 34f or the toner transported by the blade portion 34b, causing repeated OFF times (Toff1, Toff2, etc. in the figure), it is possible to obtain a system that is resistant to noise and capable of detecting the phase of the agitating member 34 in a stable manner by providing a characteristic OFF time that is longer than the other OFF times.

[0137] Example 3 Next, a third embodiment of the present invention will be described. Fig. 16 is a perspective view of the stirring member 34 in the third embodiment. In the third embodiment, there are two blades 34b. The first blade 34b1 is the same member as the blade 34b shown in the first and second embodiments. A T-seal 34g and a second blade 34b2 are installed so as to overlap the first blade 34b1. The T-seal 34g is shown in a straightened state.

[0138] The second blade portion 34b2 has a radial length shorter than that of the first blade portion 34b1. While the first blade portion 34b1 enters the development opening 39 and plays a role in transporting toner to the development portion, the second blade portion 34b2 is set to a length that allows it to enter just below the light guide 600 and plays a role in scraping out toner that tends to accumulate just below the light guide 600.

[0139] In this embodiment, an auxiliary member (fourth sheet) 34h is placed between the cleaning members 34f, at a phase position of 180° with respect to the cleaning members 34f, and in the longitudinal center where the optical path of the light guide 600 is placed. This auxiliary member 34h plays a role in suppressing the generation of noise during the ON time after the cleaning members 34f clean the light guide 600.

[0140] The auxiliary member 34h is attached to the agitation shaft 34a so as to be overlapped with the cleaning member 34f. When viewed in the longitudinal direction, the direction in which the auxiliary member 34h extends from the agitation shaft 34a is opposite to the direction in which the cleaning member 34f extends from the agitation shaft 34a. The auxiliary member 34h is configured such that one end (seventh end) in the direction of the rotation axis is included in the attachment part (fourth attachment part) 34h1 attached to the agitation shaft 34a, and the length from the one end to the other end (eighth end) is shorter than that of the cleaning member 34f. Specifically, the length is configured so as not to block the optical path of the light guide 600. The longitudinal width of the auxiliary member 34h is approximately the same as that of the cleaning member 34f, and is narrower than that of the blade part 34b. The auxiliary member 34h may be configured of a sheet similar to that of the blade part 34b and the cleaning member 34f.

[0141] 19(a) to 19(c) are cross-sectional views of the developing container 32 in the third embodiment. Fig. 19(a) is a schematic cross-sectional view of the developing container 32 in an unused image forming apparatus 1. Fig. 19(b) shows a schematic cross-sectional view of the developing container 32 immediately before the tip of the blade portion 34b passes through the light guide 600 when the toner in the developing container 32 is low near the toner level LOW. Fig. 19(c) is a schematic cross-sectional view of the developing container 32 immediately after the tip of the blade portion 34b passes through the light guide 600, moving further from the state shown in Fig. 19(b).

[0142] Fig. 17(a) shows an example of a voltage waveform based on a light receiving signal of the light receiving unit 53 at a toner level LOW in the third embodiment. The role of the auxiliary member 34h will be described below. For comparison, Fig. 17(b) and Fig. 17(c) show two patterns of voltage waveforms of a comparative example configuration in which the auxiliary member 34h is not provided.

[0143] As described above, in this embodiment, the amount of toner remaining in the developing container 32 is determined by the ratio of the ON time to one revolution time Ta of the stirring member 34. The ON time after the cleaning member 34f passes continues until the toner conveyed by the second blade portion 34b2 falls toward the light guide 600 and blocks the light path. However, the amount of toner falling from the second blade portion 34b2 and the timing at which the toner starts to fall vary from time to time. Therefore, in the comparative example configuration in which the auxiliary member 34h is not provided, a waveform such as that shown in FIG. 17(b) or FIG. 17(c) appears randomly.

[0144] 17(b) shows a voltage waveform in a comparative example configuration in which the auxiliary member 34h is not provided, in which most of the toner carried by the second blade portion 34b2 falls from the second blade portion 34b2 in one go. After the timing F when the cleaning member 34f passes the light guide 600, the toner on the second blade portion 34b2 falls while scattering toward the light guide 600 installed on the wall surface of the developing container 32. In this case, there is toner that directly blocks the optical path of the light guide 600, and the OFF time occurs at the timing Z11a in the figure. After the toner falls to the bottom of the developing container 32 in one go, the toner floating around the light guide 600 gradually settles down from the timing Z11b in the figure, and the ON time gradually returns.

[0145] 17(c) shows a voltage waveform in the case where the toner carried by the second blade portion 34b2 gradually falls, little by little, while moving along the vicinity of the agitation shaft 34a. After timing F when the cleaning member 34f passes the light guide 600, there is no toner that directly blocks the optical path of the light guide 600, so most of the time is ON. However, from timing Z21a when the toner starts to fall to timing Z21c when the toner stops falling, there is always toner floating around the light guide 600. For this reason, the optical path of the light guide 600 may be momentarily blocked, and timings (Z21a, Z21b, Z21c) when the voltage drops in a noise-like manner during the ON time occur.

[0146] Here, FIG. 17(a) shows a voltage waveform in Example 3 in which the auxiliary member 34h is installed. In this example, since the auxiliary member 34h is installed, the toner on the second blade portion 34b2 falls on the auxiliary member 34h at the longitudinal center. Therefore, after the timing F when the cleaning member 34f passes through the light guide 600, the toner on the second blade portion 34b2 does not directly block the optical path of the light guide 600, and the ON time continues longer than in the comparative examples shown in FIG. 17(b) and FIG. 17(c). The timing Z1 is when the toner on the auxiliary member 34h blocks the optical path of the light guide 600 when it falls to the bottom of the developing container 32, and the ON time continues until then. The generation of noise as shown in FIG. 17(c) has disappeared.

[0147] After the timing Z1 when the toner on the auxiliary member 34h blocks the optical path of the light guide 600, there is a timing Z2 when the voltage of the voltage waveform drops when the second blade portion 34b2 passes through the light guide 600. At this timing, the toner on the second blade portion 34b2 has already The toner falls to the bottom of the image container 32. Therefore, there is almost no toner blocking the optical path of the light guide 600, but when the second blade portion 34b2 itself passes through the optical path portion of the light guide 600, the voltage drops slightly. After that, the OFF time occurs at timing Z3 when the toner that has entered and been transported between the second blade portion 34b2 and the first blade portion 34b1 falls on the optical path of the light guide 600. When the toner falls to the bottom of the developer container 32, the ON time returns. Then, the first blade portion 34b1 enters the toner surface accumulated at the bottom of the developer container 32 and raises the toner surface, which starts to block the light guide 600, at timing Z4. This embodiment also has a T seal 34g, and the OFF time continues until timing A', which is slightly later than timing A when the first blade portion 34b1 passes through the light guide 600, and the Toffa' time is longer. In this embodiment, the longest continuous OFF time Toffa' during one revolution of the stirring member 34 at the toner level LOW is 0.3 seconds.

[0148] Incidentally, in this embodiment as well, the remaining toner level is determined based on the proportion of ON time during one revolution of the agitating member 34. Even in the comparative example configuration in which the auxiliary member 34h is not provided, there is no significant difference in the total ON time between the voltage waveforms in Figure 17(b) and Figure 17(c), so that randomly taking the voltage waveform in Figure 17(b) or Figure 17(c) has little effect on the remaining toner detection accuracy.

[0149] However, the voltage waveform can be stabilized as shown in Fig. 17(a) to suppress the influence of unexpected noise. According to this embodiment, the configuration with the auxiliary member 34h suppresses the occurrence of randomly generated noise-like OFF times of 0.1 seconds or less, and a clear ON time can be provided after the timing F at which the cleaning member 34f passes the light guide 600. Furthermore, the T seal 34g is provided, and the OFF time can be continued even after the timing A at which the first blade portion 34b1 passes the light guide 600, so that a clear long OFF time Toffa' can be provided.

[0150] In this way, by suppressing the generation of noise and forming long, clear ON and OFF times, it is possible to obtain a system that can stably detect the remaining toner level and the phase of the agitator 34.

[0151] In this embodiment, the phase is detected by the OFF time Toffa during which the light guide 600 is blocked by the toner transported by the blade portion 34b, but the method is not limited to this. For example, the phase may be detected by detecting the number of times the light is turned OFF or ON during one rotation of the stirring member 34, or a pattern in which ON and OFF are repeated in a characteristic manner.

[0152] In this embodiment, the voltage value after the light receiving signal of the light receiving unit 53 is converted into a voltage value by the A / D conversion unit 95 is used to distinguish the ON time and the OFF time with a threshold value of 1V, and the phase of the agitating member 34 is detected, but the present invention is not limited to this. For example, FIG. 18 shows a case where the threshold value of the ON time and the OFF time is 3V, with the same waveform as the voltage waveform of the comparative example configuration shown in FIG. 17(c). In such a case, the ON time is only immediately after the timing F when the cleaning member 34f cleans the light guide 600. This is because there is a certain amount of toner flying around inside the developing container 32, and the light path of the light guide 600 may be dirty, so that the amount of light received by the light receiving unit 53 shows a maximum value only in the ON time Ton4 immediately after the timing F when the cleaning member 34f cleans the light guide 600. In other words, with this configuration, it is possible to detect the phase that the timing F immediately before the ON time Ton4 is the timing when the cleaning member 34f of the agitating member 34 passes through the light guide 600. In this way, by appropriately changing the discrimination threshold value between the ON time and the OFF time, it may be possible to detect a characteristic portion of the voltage waveform and to detect the phase of the stirring member 34.

[0153] The members attached to the stirring member 34 shown in the embodiment so far are merely examples. For example, In some cases, the optical path of the light guide 600 is less likely to become dirty with toner and so cleaning member 34f is not necessary, and in other cases, multiple blade portions 34b are present. Even if the voltage waveform based on the light reception signal of light receiving portion 53 changes due to such different component arrangements of the agitating member or the addition of components, it is possible to detect the phase of agitating member 34 by detecting characteristic ON and OFF times during one revolution of agitating member 34.

[0154] The configurations and control methods of the above-described embodiments can be combined with each other as much as possible.

[0155] The disclosure of the embodiments of the present invention includes the following configurations. (Configuration 1) An image carrier; a developer carrier that carries a developer for developing the electrostatic latent image formed on the image carrier; a frame having a developing chamber in which the developer carrier is disposed and a storage chamber communicating with the developing chamber and storing a developer; a stirring member provided inside the storage chamber, the stirring member having a rotating shaft rotatable around a rotation axis line, and a sheet having a first end, which is one end in the direction of the rotation axis line, fixed to the rotating shaft and a second end, which is the other end, being a free end, and stirring the developer by the sheet rotating together with the rotating shaft; a sensor including a light-emitting element that emits light toward the inside of the storage chamber, and a light-receiving element that receives the light emitted by the light-emitting element and that passes through the inside of the storage chamber and is emitted to the outside of the storage chamber, the sensor emitting a signal having an intensity corresponding to the amount of light received by the light-receiving element; Equipped with In an image forming apparatus, the sheet of the stirring member is configured to block an optical path of light emitted from the light emitting element in the interior of the accommodation chamber once during one period in which the stirring member rotates around the rotation axis, The image forming apparatus further comprises a phase detection means for detecting the rotation phase of the stirring member based on the period during which the intensity of the signal is continuously below the threshold value for the longest period during the one cycle. (Configuration 2) The one period includes a plurality of first periods during which the intensity of the signal is continuously lower than the threshold value, The image forming apparatus according to configuration 1, wherein the phase detection means detects the rotational phase of the stirring member based on the end timing of the first period during which the period during which the signal intensity is below a threshold is the longest among the plurality of first periods. (Configuration 3) The image forming apparatus according to configuration 1 or 2, characterized in that, when the one cycle includes only one second period during which the intensity of the signal exceeds the threshold value, the phase detection means detects the rotation phase of the stirring member based on the start timing of the second period. (Configuration 4) 4. The image forming apparatus according to any one of configurations 1 to 3, wherein the first period includes a period during which the stirring member blocks the optical path. (Configuration 5) the stirring member has a first sheet, a third end which is one end in the direction of the rotation axis of the sheet and is fixed to the rotation shaft, and a fourth end which is the other end of the sheet and is a free end, the second sheet rotates together with the rotation shaft to come into contact with an optical path surface through which light emitted by the light-emitting element passes on an inner wall surface of the accommodation chamber, thereby cleaning the optical path surface; the plurality of first periods include a first OFF period including a period during which the first sheet blocks the optical path, and a second OFF period including a period during which the second sheet blocks the optical path, the first OFF period is longer than the second OFF period; The phase detection means detects the phase of the stirring motor based on a timing at which the first OFF period occurs. 5. The image forming apparatus according to any one of configurations 1 to 4, further comprising a step of detecting a rotation phase of the stirring member. (Configuration 6) The rotating member is a first attachment surface to which the first end of the first sheet is attached; a second attachment portion to which the third end portion of the second sheet is attached; having 6. The image forming apparatus according to any one of configurations 1 to 5, wherein a perpendicular line to the first mounting surface and a perpendicular line to the second mounting surface are orthogonal to each other. (Configuration 7) When viewed in the direction of the rotation axis of the rotating member, An image forming apparatus according to any one of configurations 1 to 6, characterized in that the length of the first sheet measured along the extension direction of the first sheet from the first end to the second end is longer than the length of the second sheet measured along the extension direction of the second sheet from the third end to the fourth end. (Configuration 8) In the direction of the rotation axis, 8. The image forming apparatus according to any one of configurations 1 to 7, wherein the second sheet has a width narrower than that of the first sheet. (Configuration 9) The image forming apparatus according to any one of configurations 1 to 8, characterized in that the stirring member is a third sheet attached to the rotating shaft so as to be overlapped on the first sheet, and the third sheet has a fifth end, which is one end in the direction of the rotation axis, fixed to the rotating shaft, and a sixth end, which is the other end, adhered to an inner wall of the developer storage chamber so as to seal an opening communicating between the developing chamber and the developer storage chamber when the frame is new. (Configuration 10) When viewed in the direction of the rotation axis of the rotating member, An image forming apparatus according to any one of configurations 1 to 9, characterized in that the length of the third sheet measured along the extension direction of the third sheet from the fifth end to the sixth end is longer than the length of the first sheet. (Configuration 11) 11. The image forming apparatus according to any one of configurations 1 to 10, wherein the width of the third sheet in the direction of the rotation axis is wider than the width of the first sheet in the direction of the rotation axis. (Configuration 12) The width of the first sheet in the direction of the rotation axis is narrower than the width of the opening in the direction of the rotation axis, 12. The image forming apparatus according to any one of configurations 1 to 11, wherein the length of the first sheet is such that the first sheet can enter the developing chamber through the opening. (Configuration 13) The image forming apparatus according to any one of configurations 1 to 12, characterized in that the stirring member is a fourth sheet attached to the rotating member so as to be overlapped on the second sheet, and a seventh end, which is one end in the direction of the rotation axis, is fixed to the rotating shaft, and the length from the seventh end to the other end, which is an eighth end, is a length that does not obstruct the optical path. (Configuration 14) When viewed in the direction of the rotation axis of the rotating member, An image forming apparatus according to any one of configurations 1 to 13, characterized in that the direction in which the second sheet extends from the third end to the fourth end and the direction in which the fourth sheet extends from the seventh end to the eighth end are opposite to each other. (Configuration 15) 15. The image forming apparatus according to any one of configurations 1 to 14, wherein the width of the fourth sheet in the direction of the rotation axis is narrower than the width of the first sheet in the direction of the rotation axis. [Explanation of symbols]

[0156] 1...image forming apparatus, 21...photosensitive drum (image carrier), 31...developing roller (developer carrier), 32...developing container, 32a supply port (developer receiving port), 32c...inlet (developer inlet) 32d...toner storage chamber (developer storage chamber), 34...agitating member, 34a...agitating shaft, 34b...blade portion, 34c...agitating gear, 34f...cleaning member, 34h...auxiliary member, 34g...T-seal, 35...developing blade, 39...developing opening, 40...supply container (toner pack), 50...optical detection means for detecting remaining toner amount, 52...light emitting portion of optical detection means, 53...light receiving portion of optical detection means, 600...light guide of optical detection means

Claims

1. An image carrier; a developer carrier that carries a developer for developing the electrostatic latent image formed on the image carrier; a frame having a developing chamber in which the developer carrier is disposed and a storage chamber communicating with the developing chamber and storing a developer; a stirring member provided inside the storage chamber, the stirring member having a rotating shaft rotatable around a rotation axis line, and a sheet having a first end, which is one end in the direction of the rotation axis line, fixed to the rotating shaft and a second end, which is the other end, being a free end, and stirring the developer by the sheet rotating together with the rotating shaft; a sensor including a light-emitting element that emits light toward the inside of the storage chamber, and a light-receiving element that receives the light emitted by the light-emitting element and that passes through the inside of the storage chamber and is emitted to the outside of the storage chamber, the sensor emitting a signal having an intensity corresponding to the amount of light received by the light-receiving element; Equipped with In an image forming apparatus, the sheet of the stirring member is configured to block an optical path of light emitted from the light emitting element in the inside of the accommodation chamber once during one rotation cycle of the stirring member around the rotation axis, an image forming apparatus comprising: a phase detection means for detecting a rotational phase of the stirring member based on a period during which the intensity of the signal is continuously below a threshold value for the longest time during one period;

2. The one period includes a plurality of first periods during which the intensity of the signal is continuously lower than the threshold value, 2. The image forming apparatus according to claim 1, wherein the phase detection means detects the rotational phase of the stirring member based on the end timing of the first period during which the period during which the signal intensity is below the threshold is the longest among the plurality of first periods.

3. If the one period includes only one second period in which the intensity of the signal exceeds the threshold, 3. The image forming apparatus according to claim 2, wherein the phase detection means detects the rotation phase of the stirring member based on a start timing of the second period.

4. 4. The image forming apparatus according to claim 3, wherein the first period includes a period during which the stirring member blocks the optical path.

5. the stirring member has a second sheet, the second sheet having a third end, which is one end in the direction of the rotation axis, fixed to the rotation shaft and a fourth end, which is the other end, as a free end, with the sheet as a first sheet, the second sheet rotates together with the rotation shaft to come into contact with an optical path surface through which light emitted by the light-emitting element passes on an inner wall surface of the accommodation chamber, thereby cleaning the optical path surface; the plurality of first periods include a first OFF period including a period during which the first sheet blocks the optical path, and a second OFF period including a period during which the second sheet blocks the optical path, the first OFF period is longer than the second OFF period; 4. The image forming apparatus according to claim 3, wherein the phase detection means detects the rotation phase of the stirring member based on the timing at which the first OFF period occurs.

6. The rotation axis is a first mounting surface to which the first end of the first sheet is attached; a second mounting surface to which the third end of the second sheet is attached; and having 6. The image forming apparatus according to claim 5, wherein a perpendicular line to said first mounting surface and a perpendicular line to said second mounting surface are orthogonal to each other.

7. When viewed in the direction of the rotation axis, 7. An image forming apparatus as described in claim 6, characterized in that the length of the first sheet measured along the extension direction of the first sheet from the first end to the second end is longer than the length of the second sheet measured along the extension direction of the second sheet from the third end to the fourth end.

8. In the direction of the rotation axis, 8. The image forming apparatus according to claim 7, wherein the second sheet has a width narrower than that of the first sheet.

9. The image forming apparatus described in claim 8, characterized in that the stirring member is a third sheet attached to the rotating shaft so as to be overlapped on the first sheet, and the third sheet has a fifth end, which is one end in the direction of the rotation axis, fixed to the rotating shaft, and a sixth end, which is the other end, adhered to the inner wall of the storage chamber so as to seal the opening connecting the developing chamber and the storage chamber when the frame is new.

10. When viewed in the direction of the rotation axis, 10. The image forming apparatus according to claim 9, wherein a length of the third sheet measured along an extension direction of the third sheet from the fifth end to the sixth end is longer than the length of the first sheet.

11. 11. The image forming apparatus according to claim 10, wherein the width of the third sheet in the direction of the rotation axis is wider than the width of the first sheet in the direction of the rotation axis.

12. a width of the first sheet in the direction of the rotation axis is narrower than a width of the opening in the direction of the rotation axis; 12. The image forming apparatus according to claim 11, wherein the length of the first sheet is a length that allows the first sheet to enter the developing chamber through the opening.

13. The image forming apparatus according to claim 12, characterized in that the stirring member is a fourth sheet attached to the rotating shaft so as to be overlapped on the second sheet, the seventh end being one end in the direction of the rotation axis, fixed to the rotating shaft, and the length from the seventh end to the eighth end being the other end, being a length that does not obstruct the optical path.

14. When viewed in the direction of the rotation axis of the rotating member, 14. The image forming apparatus according to claim 13, wherein a direction in which the second sheet extends from the third end to the fourth end and a direction in which the fourth sheet extends from the seventh end to the eighth end are opposite to each other.

15. 15. The image forming apparatus according to claim 14, wherein the width of the fourth sheet in the direction of the rotation axis is narrower than the width of the first sheet in the direction of the rotation axis.

Images