Image forming apparatus

Abstract

To provide a new form of an image forming apparatus employing a system of collectively supplying toner by using a toner container.SOLUTION: An image forming apparatus comprises a single motor that supplies a driving force to rotate a photoconductor drum 21, a charging roller 22, a developing roller 31, and a stirring member 34 individually, and executes first stop control of stopping the rotation of the motor after completion of an image forming operation, and second stop control of stopping bias application performed by a charging bias application unit and a developing bias application unit individually for stop timing of the rotation of the motor by the first stop control. The image forming apparatus starts the second stop control after the lapse of a waiting time from detection timing so that a rotational phase of the stirring member 34 at the stop timing is a rotational phase within a predetermined range on the basis of the rotational phase of the stirring member 34 detected at the detection timing after the completion of the image forming operation and a time required for the second stop control.SELECTED DRAWING: Figure 5

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 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 in a lump into the developing container without replacing the process cartridge. [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 new embodiment of the toner supply type image forming apparatus disclosed in Patent Document 1. [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 forming apparatus to which a toner container can be attached, A rotating photosensitive drum; a charging roller that rotates in contact with the surface of the photosensitive drum; a charging bias applying unit that applies a charging bias to the charging roller; a developing roller that carries a developer and rotates to supply toner to the photosensitive drum; a developing bias applying section that applies a developing bias to the developing roller; a mounting portion into which the toner container can be mounted so that a portion of the toner container is exposed to the outside of the image forming apparatus, the mounting portion being provided with a refill port through which toner is replenished in the toner container; a frame having a developing chamber in which the developing roller is disposed, and a storage chamber in which toner is stored and which is connected to the developing chamber and has a storage chamber opening that can communicate with the supply port; The stirring member is provided in the storage chamber, and includes a rotating shaft that rotates around a rotation axis, a first end that is one end in a direction perpendicular to the rotation axis, and a second end that is a sheet having a second end that is capable of contacting an inner wall of the toner storage chamber, the agitating member rotating to agitate the toner stored in the toner storage chamber; a phase detection means for detecting a rotation phase of the stirring member; a single motor for supplying driving forces for rotating the photosensitive drum, the charging roller, the developing roller, and the stirring member; a control unit that controls the charging bias application unit, the developing bias application unit, and the motor; Equipped with an image forming apparatus which executes a first stop control for stopping the rotation of the motor after an image forming operation is completed, and a second stop control for stopping bias application by the charging bias application unit and the developing bias application unit toward a timing at which the rotation of the motor is stopped by the first stop control, The control unit is characterized in that, based on the rotational phase of the stirring member detected at the detection timing after the end of the image forming operation and the time required for the second stop control, it starts the second stop control after a waiting time has elapsed from the detection timing so that the rotational phase of the stirring member at the stop timing is within a predetermined range of rotational phase. Effect of the Invention

[0006] According to the present invention, it is possible to provide a new embodiment of an image forming apparatus that uses a toner supply system in which toner is replenished all at once. [Brief description of the drawings]

[0007] [Figure 1] 1 is a cross-sectional view and a perspective 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] Image formation process flow chart [Figure 4] A perspective view and a front view of the process cartridge 20 and the toner pack 40 [Diagram 5] FIG. 13 shows the phase of the stirring member 34 during replenishment and the state of toner mixing by subsequent stirring. [Figure 6] FIG. 13 shows the phase of the stirring member 34 during replenishment and the state of toner mixing by subsequent stirring. [Figure 7] FIG. 13 shows another phase of the stirring member 34 during replenishment. [Figure 8] FIG. 13 shows another phase of the stirring member 34 during replenishment. [Figure 9] FIG. 13 is a diagram showing the phase of the stirring member 34 during replenishment in the second embodiment. [Figure 10] Cross-sectional view of a process cartridge according to a third embodiment [Figure 11] Cross-sectional view of a process cartridge according to a third embodiment [Figure 12] FIG. 13 shows a toner remaining amount sensor 50 according to a third embodiment. [Figure 13] FIG. 13 is a diagram showing the phase of the stirring member 34 and the toner mixing state during replenishment in the third embodiment. [Figure 14]FIG. 13 is a diagram showing the phase of the stirring member 34 and the toner mixing state during replenishment in the third embodiment. [Figure 15] 13 is a timing chart showing control timings of a phase determination process and a phase adjustment process in the fourth embodiment. [Figure 16] FIG. 13 is a diagram showing the positional relationship of parts that control the potential of the photosensitive drum 21 in the fourth embodiment. [Figure 17] Block diagram of the main control unit 100 in the fourth embodiment [Figure 18] Timing chart of stop control of the photosensitive drum 21 in the fourth embodiment [Figure 19] 13 is a timing chart showing the relationship between phase adjustment and stop processing in the fourth embodiment. [Figure 20] Timing chart of stop control of the second photosensitive drum 21 in the fifth embodiment [Figure 21] Control flow chart of stop control selection and phase adjustment process in the fifth embodiment [Figure 22] 13 is a timing chart showing the relationship between the extension of post-processing, phase adjustment, and stop processing in the sixth embodiment. [Diagram 23] A control flowchart of post-processing extension, phase adjustment, and stop processing in the sixth embodiment [Figure 24] 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 merely 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 do not limit the scope of the claims. It is not intended to do so.

[0009] Example 1 Fig. 1(a) 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. 1(b) is a perspective view of the image forming apparatus 1 according to this embodiment. Fig. 2 is a schematic perspective view showing the configuration of an agitating member. 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] 1(a) shows a state in which the image forming apparatus 1 is installed on a horizontal plane as a 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 back direction (the direction from the front side of the device to the back side), and the right direction on the paper is called the front direction (the direction from the back side of the device to the front side). Also, 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 right direction.

[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 (charging member) 22, a pre-exposure device (discharging means) 23, and a developing roller (developer carrier) 31 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 in a predetermined direction (clockwise direction in the figure) at a predetermined process speed by a driving force supplied from a motor.

[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 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 contains the toner supplied to the developing roller 31 and the supply roller 33 in the developing chamber 32e. A protrusion (A in FIG. 1(a)) is provided to hold the toner. The boundary between the toner storage chamber 32d and the developing chamber 32e at a position corresponding to the protrusion A is referred to as a developing opening 39. Note that the supply roller 33 is not necessarily required as long as the configuration can 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] In addition, the stirring member 34 is rotatably provided inside the toner storage chamber 32d of the developing container 32. As shown in FIG. 2, the stirring member 34 has a stirring shaft (rotating member) 34a extending in the longitudinal direction and a blade portion (sheet) 34b extending radially outward from the stirring shaft 34a. The blade portion 34b is attached to the stirring shaft 34a so that a mounting portion 34b11, which is a part of the blade portion 34b, contacts a mounting surface 34a1 of the stirring shaft 34a extending in the direction of the rotation axis of the stirring shaft 34a. The blade portion 34b is configured such that a first end 34be1, which is one end in a direction perpendicular to the rotation axis, is fixed to the stirring shaft 34a as a part of the mounting portion 34b11, and a second end 34be2, which is the other end, can contact the inner wall of the toner storage chamber 32d. The stirring member 34 is rotated about the stirring shaft 34a by a motor drive via a gear 34c.

[0022] 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.

[0023] In this embodiment, the gear 34c of the stirring member 34 is provided with a blade portion 34b of the stirring member 34. Pin 34d is disposed at the corresponding position. Fig. 2 shows a state in which gear 34c is removed from stirring member 34. Phase detection sensor 51 is a reflective photointerrupter, and by detecting the presence or absence of pin 34d, the control unit of image forming apparatus 1 can determine the phase of stirring member 34. That is, phase detection sensor 51 has a light emitting unit (light emitting element) and a light receiving unit (light receiving element), and is configured to be able to grasp the position (phase) of pin 34d by detecting detection light emitted from the light emitting unit and reflected by pin 34d and received by the light receiving unit. Note that the configuration of phase detection sensor 51 is not limited to a reflective type, and a transmission type sensor may also be used.

[0024] (Image formation operation) The image forming operation of the image forming apparatus 1 will be described with reference to Figures 1(a), 1(b) and 3. Figure 3 is a flowchart of the image forming process.

[0025] 3, 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-treatment process are provided before and after the image forming process P2.

[0026] 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.

[0027] In the image formation process P2, the scanner unit 11 irradiates the photosensitive drum 21 with laser light L (see FIG. 1(a)) 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.

[0028] In parallel with this image forming process, the feeding section 60 conveys the recording material P toward a 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 supply, and the toner image carried on the photosensitive drum 21 is transferred onto the recording material P.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] In this embodiment, after the post-rotation process P3, a phase determination process P4 is performed to determine the phase of the blade portion 34b of the stirring member 34 disposed in the developing container 32 in preparation for toner replenishment. After the phase determination process P4, a phase adjustment process P5 is performed to stop the motor drive at a timing when the position of the blade portion 34b of the stirring member 34 reaches a predetermined position, and the image forming operation is terminated. The configuration related to toner supply, the phase determination process P4, and the phase adjustment process P5 will be described in detail later.

[0033] (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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] (Configuration related to toner supply) As shown in FIG. 1B, in this embodiment, which is a toner supply type, 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.

[0038] 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.

[0039] 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 inside of 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 accommodation 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 used for image formation. By placing it at the front side of the apparatus 1, the user can easily replenish toner to the developing container 32.

[0040] 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.

[0041] 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.

[0042] The toner supplied from the supply port 32a is sent toward the developing roller 31 and the supply roller 33 as the stirring member 34 inside 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, but the toner is distributed throughout the entire developing container 32 as the stirring member 34 rotates repeatedly.

[0043] 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. 24. Fig. 24 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.

[0044] The scanner unit 11 includes a light source 210, an aperture 211, an incident optical element 212, a deflector 213, and an imaging optical element 214. The light source 210 is, for example, a semiconductor laser. The aperture 211 has an elliptical opening and limits the diameter of the light beam emitted from the light source 210 in each of the main scanning direction and the sub-scanning direction. The incident optical element 212 has a positive refractive power in the main scanning cross section and converts the light beam that has passed through the aperture 211 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 211 is converted into a weakly convergent light beam, thereby reducing the refractive power required for the imaging optical element 214. The incident optical element 212 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 211 near the deflection surface 213a of the deflector 213 in the sub-scanning cross section.

[0045] The imaging optical element 214 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 213 in both the main scanning section and the sub-scanning section. Specifically, the imaging optical element 214 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 213a of the deflector 213 scans the scanned surface of the photosensitive drum 21 with desired scanning characteristics in the main scanning section. In addition, the imaging optical element 214 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 213a is tilted) by making the vicinity of the deflecting surface 213a of the deflector 213 and the vicinity of the scanned surface of the photosensitive drum 21 in a conjugate relationship with each other in the sub-scanning section.

[0046] In this way, the light beam emitted from the light source 210 passes through the diaphragm 211 and the incident optical element 212, and then enters the deflection surface 213a of the deflector 213. Then, the light beam reflected and deflected by the deflection surface 213a of the deflector 213 is guided to the scanned surface of the photosensitive drum 21 by the imaging optical element 214. The deflector 213 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 E, thereby forming an electrostatic latent image on the scanned surface of the photosensitive drum 21.

[0047] 24 and 1(a), 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.

[0048] 24, 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 214, and not to increase the size of the device in the left-right direction and the front-rear direction of the device.

[0049] (Phase of blade portion 34b and mixture state of new and old toner during replenishment) The toner (hereinafter referred to as new toner) supplied from the supply port 32a by the toner pack 40 is introduced into the toner storage chamber 32d through the introduction port 32c, and is distributed throughout the entire longitudinal area of ​​the toner storage chamber 32d by the rotation of the stirring member 34 in the toner storage chamber 32d. The new toner is gradually mixed with the toner (hereinafter referred to as old toner) that was originally present in the developing container 32.

[0050] Here, it was found that the degree to which new toner enters the toner storage chamber 32d differs depending on the stop phase of the blade portion 34b of the stirring member 34 before the start of rotation when new toner is replenished. Specifically, it was found that there are cases in which the new toner instantly spreads over the entire longitudinal area of ​​the toner storage chamber 32d and enters, and cases in which the new toner remains in the longitudinal area of ​​the toner storage chamber 32d near the inlet 32c. It was also found that in each case, the time required for the new toner and the old toner to be uniformly mixed by the rotation of the stirring member 34 after the new toner is replenished by the toner pack 40 differs greatly.

[0051] 5(a) to 6(d) are schematic diagrams showing the state of new toner (hatched area) supplied from the toner pack 40 and old toner (filled area) in the developing container 32. FIG. 5(a) and FIG. 6(a) are schematic cross-sectional views of the developing container 32 as viewed from the side (left side). FIG. 5(b) to FIG. 5(d) and FIG. 6(b) to FIG. 6(d) are schematic diagrams showing the inside of the developing container 32 as viewed from the front side. FIG. 5(a) to FIG. 6(d) are diagrams showing how the new toner actually mixes with the old toner when a transparent developing container 32 is prepared and yellow toner is used as the new toner in the toner pack 40 and black toner is used as the old toner in the transparent developing container 32. FIG. 5(b) to FIG. 5(d) and FIG. 6(b) to FIG. 6(d) show the state seen from the front side in the range including the stirring shaft 34a of the stirring member 34.

[0052] "Immediately after replenishment" here means before the agitating member 34 starts to rotate. The image diagrams viewed from the front also show the state immediately after replenishment, 10 seconds after the agitating member 34 starts to rotate (after 10 rotations of the agitating member 34), and 30 seconds after (after 30 rotations of the agitating member 34). The solid areas show areas where the proportion of old toner is high, and the shaded areas show areas where the proportion of new toner is high. The dotted areas indicate areas where the new toner and the old toner are well mixed.

[0053] Figures 5(a) to 5(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 farthest from inlet 32c. Figures 6(a) to 6(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.

[0054] Here, the position farthest from the inlet 32c is defined as follows. The inlet 32c is located in the first quadrant of a two-dimensional Cartesian coordinate system that is divided by an axis (second virtual line) in the direction of gravity and an axis (first virtual line) in the direction perpendicular to the direction of gravity (horizontal direction) with the rotation axis (center of rotation) of the stirring shaft 34a of the stirring member 34 as the center. With respect to the inlet 32c located in the first quadrant as one quadrant, the developing unit such as the photosensitive drum 21 and the developing roller 31 is located in the second quadrant as the other quadrant. In this case, the state in which the tip of the blade portion 34b of the stirring member 34 before replenishment is located in the third quadrant is defined as the position farthest from the inlet 32c. On the other hand, when the tip position of the blade portion 34b of the stirring member 34 during replenishment is located on the inlet 32c side, it means that the tip of the blade portion 34b of the stirring member 34 before replenishment is located in the same first quadrant as the inlet 32c.

[0055] In addition, the positional relationship of each component of the device using the above coordinate system does not require the device layout to strictly arrange each component in each quadrant. That is, the inlet 32c may be arranged so that a part of it (a large part of the inlet 32c) is included in the first quadrant and the other part protrudes into the other quadrants. Similarly, the blade portion 34b of the stirring member 34 may be arranged so that at least a part of the blade portion 34b including the tip (second end portion 34be2) of the blade portion 34b is included in the third quadrant and the other part protrudes into the other quadrants. Other positional relationships using the above coordinate system described below may be considered in the same manner.

[0056] As shown in Figures 5(a) to 5(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.

[0057] However, on the other hand, as shown in FIG. 6(a) to FIG. 6(d), when the tip position of the vane portion 34b is located on the inlet 32c side during the supply of new toner, the new toner stays directly below the inlet 32a in the toner supply path from the inlet 32a inside the protruding portion 38 to the inlet 32c. The reasons for this state are considered to be as follows. One is that the vane portion 34b at this time is in a state before the old toner is sent toward the development opening 39 where the development roller 31 and the supply roller 33 are located, and the bottom of the development container 32 is filled with old toner. Another is that the vane portion 34b blocks the discharge space of the new toner. As a result, the new toner is discharged all at once into a narrow space, and the new toner accumulates in the protruding portion 38 as described above. The more the powder toner is discharged into a narrow space, the more it becomes clogged due to the pressure of the toner itself and the friction with each side surface. Therefore, the new toner is less likely to spread longitudinally inside the development container 32.

[0058] The purpose of this embodiment is to achieve, in a short time, a state in which new toner and old toner are mixed nearly uniformly in the longitudinal direction inside the developing container 32. The blade portion 34b agitates the toner in the rotational direction, but as it continues to rotate, the toner gradually mixes in the longitudinal direction as well.

[0059] As shown in Figures 6(a) to 6(d), when new toner remains in the vicinity of the inlet 32c in the longitudinal direction inside the developing container 32, even if the stirring member 34 is driven, it takes more than 30 seconds (30 rotations of the stirring member 34) for the new toner to spread throughout the entire longitudinal area.

[0060] However, as shown in Figures 5(a) to 5(d), since the tip of the blade portion 34b is located farthest from the inlet 32c, when the new toner spreads longitudinally inside the developing container 32 immediately after replenishment, it can be made uniform in about 10 seconds (10 rotations of the stirring member 34).

[0061] (Mixing old and new toner and image defects) If the image forming process is started without the old toner and the new toner being completely mixed, a poor image may occur due to poor transfer. The toner may be continuously stirred in the developing container 32, or, especially in the case of a cleanerless configuration as in this embodiment, the toner may become deformed or additives may be embedded in the toner due to repeated image forming processes. Therefore, the charging performance of the old toner may be lower than that of the new toner.

[0062] The higher the charging performance of the toner, the more easily it conforms to the potential distribution of the developing roller 31 and the photosensitive drum 21, and the more easily it is developed as a toner image into the electrostatic latent image on the photosensitive drum 21. Therefore, when old toner and new toner are mixed uniformly, the new toner in the mixed toner is preferentially used for image formation. However, if the toner is not mixed uniformly, a situation may arise in which new toner with high charging performance is used for image formation, or old toner with low charging performance is used for image formation.

[0063] Furthermore, the higher the charging performance of the toner, the stronger the bias required to transfer the toner image on the photosensitive drum 21 to the recording material P. On the other hand, if a high transfer bias is applied to a toner with low charging performance, a grainy image defect called strong dropout occurs. In other words, if the transfer bias is set to match the new toner with high charging performance, if there is an area where the old toner with low charging performance is used for image formation, a strong dropout image defect occurs. Therefore, if the mixture of the old toner and the new toner is not uniform, or if there is an area where only the old toner is present without the new toner being distributed in the longitudinal direction, strong dropout may occur in the area where the old toner was used for image formation.

[0064] In this way, the mixed state of the new and old toner varies after replenishment, making it difficult to set the transfer bias required after replenishment, and making it impossible to avoid transfer defects in the longitudinal direction. Therefore, it is desirable for the mixed state of the new and old toner to be such that the new toner is distributed as evenly as possible in the longitudinal direction.

[0065] (Phase determination process P4 and phase adjustment process P5) Therefore, in this embodiment, when the control unit 90 supplies toner from the toner pack 40 to the developing container 32, the control unit 90 controls the stirring member 34 so that the stirring member 34 stops rotating at a predetermined rotation phase at the latest by the timing when the toner passes through the inlet 32c of the developing container 32. That is, the control unit 90 controls the rotation of the stirring shaft 34a so that the tip (second end 34be2) of the blade portion 34b stops rotating in a state where it is located in a quadrant different from the quadrant where the inlet 32c is located in the above coordinate system. More specifically, the motor drive time is adjusted so that the phase of the blade portion 34b of the stirring member 34 is located farthest from the inlet 32c when the motor is stopped after the print job. After the post-rotation process P3 after the image formation process P2, a phase determination process P4 and a phase adjustment process P5 are added to end the print job.

[0066] In this embodiment, in the phase determination process P4, the phase of the blade portion 34b of the agitating member 34 is determined by the pin 34d provided on the gear 34c of the agitating member 34 and the sensor 51. After the phase determination, the process proceeds to the phase adjustment process P5. In the phase adjustment process P5, the position of the blade portion 34b of the agitating member 34 is adjusted so that the blade portion 34b is positioned at the farthest position from the desired supply port 32a. The control unit is instructed to stop the motor. Depending on the motor, there may be several msec of inertia between the time the control unit is instructed to stop and the time the motor drive is actually turned off. In the image forming apparatus of this embodiment, a brush motor is used as the motor as the drive source, and even if the current is stopped, it takes time for the motor to completely stop rotating due to inertia. Therefore, it is desirable to adjust the stop instruction timing taking inertia into consideration.

[0067] Moreover, the blade portion 34b is deformed to some extent when it comes into contact with the inner wall of the toner storage chamber 32d. The degree of the deformation may change as the phase of the agitation shaft 34a changes. That is, the shape of the inner wall surface of the toner storage chamber 32d is not uniform with respect to the rotation center of the agitation shaft 34a, and when the contact position of the blade portion 34b with the inner wall surface of the toner storage chamber 32d changes, the magnitude of the reaction force that the tip of the blade portion 34b receives from the inner wall surface of the toner storage chamber 32d also changes, and the degree of deformation may also change. The shape of the inner wall of the toner storage chamber 32d is not a cylindrical surface centered on the rotation center of the agitation member 34, and the position change of the tip of the blade portion 34b during the rotation of the agitation member 34 is not constant with respect to the phase change of the agitation shaft 34a due to the change in the degree of deformation of the blade portion 34b. That is, it is considered that the position of the rotation phase of the agitation shaft 34a and the tip position of the blade portion 34b do not necessarily correspond one-to-one. It is considered that the deformation of the blade portion 34b may change depending on the amount of toner remaining in the toner storage chamber 32d. Therefore, it is preferable to grasp the correspondence between the rotation phase of the agitator shaft 34a and the tip position of the blade portion 34b in advance by experiments or the like, and to reflect this in the control amount of the rotation control of the agitator shaft 34a.

[0068] (Effects of this embodiment) According to this embodiment, when the motor is stopped after a print job is completed, the tip of the blade portion 34b can always be positioned at the farthest position from the inlet 32c in preparation for replenishment. At this time, the old toner in the developer container 32 is pushed toward the developer opening 39, creating a space on the bottom surface of the developer container 32. Due to this space, the new toner in the toner pack is discharged while spreading over the entire length of the developer container 32 without clogging. After this, when the agitator 34 starts rotating, the mixture of the new toner and the old toner is made uniform in a shorter time than in the conventional configuration (a configuration in which the phase control of the agitator 34 is not performed).

[0069] As described above, by making the new toner uniformly present over the entire longitudinal area of ​​the developing container 32 in a shorter time than before, the possibility of image defects occurring can be further reduced.

[0070] In this embodiment, the motor is stopped by the phase adjustment process so that the tip of the blade portion 34b is located in the third quadrant of an orthogonal coordinate system centered on the rotation center of the stirring shaft 34a of the stirring member 34, but this is not limited to the above. In this embodiment, the space into which new toner of the toner pack 40 is discharged is widest when the tip of the blade portion 34b of the stirring member 34 is stopped in the third quadrant. However, for example, as shown in Figures 7(a) to 8(d), even if the tip is stopped in the second or fourth quadrant, the same effect as described above can be achieved if the new toner of the toner pack 40 is discharged into a sufficiently wide space and enters the developing container 32 while spreading in the longitudinal direction.

[0071] In addition, in this embodiment, phase determination and phase adjustment are performed after the post-rotation process P3, but the time required for the entire process of the print job can be shortened by performing position determination in parallel with the post-rotation process P3.

[0072] In addition, the phase adjustment only needs to be performed in time for toner replenishment, and the user does not need to actually replenish toner. It may be configured to execute the phase determination process P4 and the phase adjustment process P5. That is, for example, the opening and closing of the opening / closing member 83 provided on the top cover may be detected, and when it is detected that the opening / closing member 83 is opened, the motor may be driven to execute the phase determination process P4 and the phase adjustment process P5. Alternatively, it may be configured to detect the attachment of the toner pack 40 to the attachment section 57, and when it is detected that the toner pack 40 is attached to the attachment section 57, the motor may be driven to execute the phase determination process P4 and the phase adjustment process P5. That is, it may be configured to detect that the user is preparing to replenish toner (that the probability is high), and the detection that the user has started to prepare to replenish toner may be used as a trigger to start the phase adjustment of the stirring member 34.

[0073] In addition, the slower the motor drive speed (process speed) for position adjustment, the less the influence of inertia in the position adjustment. Therefore, the process speed in the phase determination process or phase adjustment process may be slower than the process speed in the image formation process. This makes it possible to perform position adjustment with high accuracy.

[0074] (others) The positional relationship of each component in the coordinate system shown in Figures 5(a) to 8(d) (the quadrant in which each component is located) is the positional relationship when the image forming apparatus is viewed from left to right. Therefore, conversely, the quadrant in which each component is located when viewed from right to left is reversed in the left-right direction of the paper. That is, for example, in the positional relationship of each component when viewed from right to left, the quadrant in which the introduction port 32c is located is the second quadrant, and the quadrant in which the tip of the blade portion 34b is stopped is the fourth quadrant, or the first or second quadrant.

[0075] 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.

[0076] 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 problem of the present invention may occur is not limited to the above-mentioned configuration shown in this embodiment.

[0077] 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 increase. 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 in the vertical direction of the device is not increased. That is, according to this embodiment, the tip of the blade portion 34b of the stirring member 34 located in the first quadrant is In a configuration of the developing container 32 that is compact and does not allow a sufficient distance between the inlet 32c and the developing port 32b, it is possible to reduce the time required for mixing the new toner and the old toner.

[0078] Example 2 Second Embodiment A second embodiment of the present invention will be described with reference to Figures 9(a) to 9(c). Figure 9 is a cross-sectional view of a developing container 32 in the second embodiment.

[0079] In the second embodiment, the stirring member 34 has a plurality of blades in order to more quickly and uniformly mix the new and old toners during replenishment. The configuration of the stirring member 34 in the image forming apparatus according to the second embodiment other than the blades is the same as that of the image forming apparatus described in the first embodiment, and therefore the description thereof will be omitted.

[0080] In this embodiment, the stirring member 34 has a first blade portion 34b1 and a second blade portion 34b2. The first blade portion 34b1 and the second blade portion 34b2 are members of the same shape made of polycarbonate. The second blade portion 34b2 is installed at a position shifted 90° downstream in the rotation direction from the first blade portion 34b1.

[0081] 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 different from the first mounting surface 34a1 around the rotation axis. The first mounting surface 34a1 and the second mounting surface 34a2 are adjacent two of 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. The first blade portion (first sheet) 34b1 has a first mounting portion 34b11 that contacts the first mounting surface 34a1. One end (first end) 34b1e1 of the first blade portion 34b1 in the direction perpendicular to the rotation axis is fixed to the agitator shaft 34a as a part of the mounting portion 34b11, and the other end (second end) 34b1e2 is capable of contacting the inner wall surface of the toner storage chamber 32d. The second blade portion (second sheet) 34b2 has an attachment portion (second attachment portion) 34b21 that contacts the second attachment surface 34a2. The second blade portion 34b2 has one end (third end) 34b2e1 in a direction perpendicular to the rotation axis that is fixed to the agitator shaft 34a as part of the attachment portion 34b21, and the other end (fourth end) 34b2e2 that can contact the toner storage chamber 32d.

[0082] When there is a large amount of toner in the developing container 32, the first blade portion 34b1 may bend more due to the resistance of the toner. When the first blade portion 34b1 is bent, toner (Y in the figure) may remain even after passing the bottom of the developing container 32. The toner Y at the bottom is mixed with the falling toner when the toner scraped off by the first blade portion 34b1 next falls toward the bottom, but compared to when the toner Y at the bottom does not remain, it may take longer for the new toner and the old toner to become uniformly mixed after new toner is replenished.

[0083] In this embodiment, the second blade portion 34b2, which is located 90° downstream of the first blade portion 34b1, can scrape off the toner Y at the bottom that remains after the first blade portion 34b1 has passed. That is, in this embodiment, the toner Y is also sent to the development opening 39. Since the toner Y is also actively encouraged to mix in this development opening 39, the stirring of the entire toner in the development container 32 progresses quickly. Even immediately after replenishment, the presence of the second blade portion 34b2 shortens the time it takes for the replenished new toner and the old toner in the development container 32 to be uniformly mixed.

[0084] (Regarding the phase of the blade and the mixture state of new and old toner during replenishment in Example 2) In the configuration having two blades as in the second embodiment, the control unit 90 controls the rotation of the stirring shaft 34a so that both ends of the two blades are located in a quadrant different from the quadrant in which the inlet 32c is located in the coordinate system, as in the first embodiment. By adjusting the phase so that replenishment occurs when the tip positions of both blade portions 34b1, 34b2 are located far from the inlet 32c, it is possible to obtain the same effect as that described in the first embodiment.

[0085] Fig. 9(a) shows a case where new toner is supplied when the tip positions of the two blades 34b1 and 34b2 are located far from the inlet 32c, Fig. 9(b) shows a case where new toner is supplied when the tip of the first blade 34b1 is located toward the inlet 32c, and Fig. 9(c) shows a case where new toner is supplied when the tip of the second blade 34b2 is located toward the inlet 32c.

[0086] 9(a), if new toner is supplied when the tip positions of the blade portions 34b1 and 34b2 are located far from the inlet 32c, the presence of the second blade portion 34b2 prevents the new toner from penetrating into the bottom surface of the developing container 32. However, since neither the blade portion 34b1 nor the blade portion 34b2 blocks the space into which new toner from the toner pack 40 is supplied into the developing container 32, the new toner is discharged into a sufficiently wide space. As a result, the new toner enters the developing container 32 while spreading over the entire longitudinal area.

[0087] 9(b) or 9(c), if new toner is replenished when the tip of either the blade portion 34b1 or the blade portion 34b2 is located on the inlet 32c side, the blade portion 34b1 or the blade portion 34b2 blocks the space into which the new toner enters. Therefore, the new toner is discharged into a narrow space, causing clogging of the discharged new toner, and the new toner remains in the developer container 32 near the protrusion 38 in the longitudinal direction.

[0088] In Example 2, as shown in Fig. 9(a), when the stirring member 34 was driven in a state in which the new toner was instantly spread in the longitudinal direction immediately after replenishment, the new toner was uniformed after 5 seconds (after 5 rotations of the stirring member 34). It was also confirmed that in this state, no transfer failure occurred after replenishment.

[0089] Example 3 An image forming apparatus according to a third embodiment will be described with reference to Figs. 10(a) to 11(b). In the second embodiment, the two blades 34b1 and 34b2 are made of the same shape and material, but this is not limited thereto. In this embodiment, a preferred configuration will be described for the developing container 32 in which a toner remaining amount sensor (developer remaining amount detection unit) 50, which is an optical detection means for optically detecting the remaining amount, is installed inside the developing container 32. Figs. 10(a) and 10(b) are schematic cross-sectional views of the developing container 32 in a comparative example in which the toner remaining amount sensor 50 is provided in a configuration in which the stirring member 34 has one blade 34b as in the first embodiment. Figs. 11(a) and 11(b) are schematic cross-sectional views of the developing container 32 in a third embodiment in which the toner remaining amount sensor 50 is provided in a configuration in which the stirring member 34 has two blades 34b3 and 34b4 as in the second embodiment.

[0090] Unlike the two blades 34b1 and 34b2 of the second embodiment, the two blades 34b3 and 34b4 of the third embodiment are attached to one mounting surface of the agitator shaft 34a so as to overlap each other. Specifically, the agitator shaft 34a has a mounting surface 34a1 extending in the direction of the rotation axis, and the blade (fourth sheet) 34b4 has a mounting portion 34b41 (fourth mounting portion) that contacts the mounting surface 34a1. One end (seventh end) 34b4e1 of the blade 34b4 in the direction perpendicular to the rotation axis is fixed to the agitator shaft 34a as a part of the mounting portion 34b41, and the other end (eighth end) 34b4e2 is capable of contacting the inner wall surface of the toner storage chamber 32d. The blade portion (third sheet) 34b3 has an attachment portion 34b31 (third attachment portion) that is attached so as to overlap with the attachment portion 34b41 of the blade portion 34b4. The blade portion 34b3 has one end (fifth end) 34b3e1 in the direction perpendicular to the rotation axis fixed to the agitator shaft 34a as part of the attachment portion 34b31, and the other end (sixth end) 34b3e2 fixed to the toner collecting portion 34b4. It is capable of coming into contact with the inner wall surface of the chamber 32d.

[0091] The short side length of the blade portion 34b (the length of the blade portion 34b from the fixed end fixed to the stirring shaft 34a to the free end on the opposite side) is usually set to a length necessary for the blade portion 34b to enter the development opening 39 and supply the toner in the development container 32 to the development opening 39. However, as shown in FIG. 10(a), the blade portion 34b may become caught on the remaining toner sensor 50. If the rotation continues further, as shown in FIG. 10(b), the tip of the blade portion 34b may pass through (go over) the remaining toner sensor 50 but may not be able to get under the remaining toner sensor 50, and may not be able to stir the toner (Y' in the figure) below the remaining toner sensor 50.

[0092] In such a case, for example, the short side length of the first blade portion 34b3 (dotted line) is shortened to an extent that it can be placed under the remaining toner sensor 50, as shown in FIG. 11(a).

[0093] The length (third length) of blade 34b3 from attachment portion 34b31 to the tip (third end) that contacts the inner wall surface of toner-accommodating chamber 32d is shorter than the same length (fourth length) of blade 34b4 from attachment portion 34b41 to the tip (fourth end). Here, the above-mentioned length of each blade refers to the length of the blade in the short direction perpendicular to the long direction, and is the length from the attachment portion to the tip measured along the extension direction of the blade when viewed in the direction of the rotation axis.

[0094] The remaining toner amount sensor 50 is located in a quadrant below the quadrant in which the inlet 32c is located in the coordinate system, and is provided so as to protrude from the inner wall of the toner storage chamber 32d. The control unit 90 controls the rotation of the agitator shaft 34a so that the end of the blade portion 34b3 is located in the quadrant in which the remaining toner amount sensor 50 is located in the coordinate system. The length from the mounting portion 34b31 to the tip (third end) of the blade portion 34b3 is a length that allows the tip of the blade portion 34b3 to enter the recess 32d5 (broken circle area in FIG. 11(b)) formed between the lower end of the remaining toner amount sensor 50 and the inner wall surface of the toner storage chamber 32d.

[0095] After the first blade portion 34b3 scrapes off the toner below the remaining toner sensor 50 and sends it to the bottom of the developing container 32, the second blade portion 34b4 agitates the toner at the bottom. With this configuration, it is possible to agitate all the toner and supply it to the developing opening 39.

[0096] In this way, each of the blades 34b may have a different role. By adjusting the phase so that new toner is replenished when all of the blade tips are located far from the inlet 32c, it is possible to obtain the same effect as that described in the first embodiment. Depending on the configuration of the developing container 32, the number, shape, and material of the blades may be appropriately selected to be different from those in the third embodiment.

[0097] (Other Effects in Example 3) Other effects obtained in the third embodiment will be described. After new toner is replenished from the toner pack 40, the old toner and the new toner in the developing container 32 are quickly and uniformly mixed, which not only improves image defects but also improves the accuracy of the remaining toner sensor 50 in detecting the amount of replenished toner.

[0098] The toner remaining amount sensor 50 for detecting the remaining amount of toner is composed of a light emitting portion 50a, a light receiving portion 50b, and a light guide 600 for guiding the light from the light emitting portion 50a. FIG. 12(a) is a cross-sectional view of the developing container 32 in the third embodiment shown in FIG. 11, taken along the B-B' plane from the rear side. The light guide 600 is disposed at the center of the developing container 32 in the longitudinal direction. In this embodiment, the light guide 600 is made of amorphous, highly transparent polyimide. Styrene ones were used.

[0099] The CPU 91 of the control unit 90 judges whether the light receiving unit (light receiving element) 50b has received light from the light emitting unit (light emitting element) 50a based on the voltage level input to the toner remaining amount sensor 50. Then, the CPU 91 calculates the length of time during which the toner remaining amount sensor 50 detects light when the toner in the developing container 32 is stirred for a certain period of time by the stirring member 34. The ROM 93 prestores, as a table 96, a toner remaining amount determination threshold value for determining the toner remaining amount from the light detection time of the toner remaining amount sensor 50. The CPU 91 calculates (predicts) the toner remaining amount in the developing container 32 based on the light detection time of the toner remaining amount sensor 50 and the threshold value stored in the table 96.

[0100] (Method of detecting remaining toner amount) 12(b) and 12(c) are perspective views of the light guide 600. Using these figures, a method for detecting the toner amount by the toner remaining amount sensor 50 will be described. FIG. 12(b) is a view seen from the outside of the developing container 32, to which a sensor having a light emitting portion 50a and a light receiving portion 50b is attached. Light from the light emitting portion 50a is received from a light entering portion 611, and the light that passes through the inside of the developing container 32 and emerges from a light exiting portion 621 is received by the light receiving portion 50b. FIG. 12(c) is a view seen from the inside of the developing container 32, in which the light received from the light entering portion 611 is reflected by surfaces 612 and 622 along the optical path Q and is output to the light exiting portion 621.

[0101] The optical path Q is blocked by the toner transported by the agitator 34 when the agitator 34 makes one rotation. The time during which the light is blocked, i.e., the time during which the light receiver 50b does not detect the light from the light emitter 50a, varies depending on the remaining amount of toner.

[0102] That is, when the remaining toner amount is large, the optical path Q is easily blocked by the toner, so that the time during which the light receiving portion 50b receives light becomes shorter and the intensity of the light received by the light receiving portion 50b becomes smaller.

[0103] On the other hand, when the remaining toner is low, the time that the light receiving portion 50b receives light becomes longer, and the intensity of the light received by the light receiving portion 50b becomes stronger. Therefore, the CPU 91 of the control portion 90 can determine the remaining toner level based on the light receiving time and light receiving intensity of the light receiving portion 50b. The toner remaining amount determination threshold value for determining the remaining toner amount from the light receiving time of the light receiving portion 50b is stored in advance in the ROM 93 as, for example, a table.

[0104] (Detection of remaining toner when refilling new toner from toner pack 40) When detecting the amount of remaining toner when new toner is replenished from the toner pack 40, the accuracy of detecting the amount of remaining toner may be reduced depending on the mixture state of the replenished new toner and the old toner in the developing container 32.

[0105] As described above, new toner has a higher charging performance than old toner. Meanwhile, inner surfaces 612 and 622 of light guide 600 on developing container 32 are charged by repeated rubbing with toner and stirring member 34. For this reason, the more highly charged toner is, the more likely it is to adhere to surfaces 612 and 622 of light guide 600, and surfaces 612 and 622 of light guide 600 are always blocked by toner, which tends to reduce the accuracy of detecting the remaining toner amount.

[0106] Therefore, if the mixture of old toner and new toner after replenishment in the developing container 32 is not uniform, the toner may easily adhere to surfaces 612 and 622 of the light guide 600 in areas where a large amount of new toner is present, which may reduce the accuracy of detecting the remaining toner amount.

[0107] On the other hand, 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.

[0108] In other words, if the new toner after replenishment is uniformly mixed with the old toner in the developing container, it is possible to suppress a decrease in the accuracy of remaining toner amount detection.

[0109] (Mixed state of new and old toner after replenishment in this embodiment) 13(a) to 14(d) show images seen from the cross section side and the front side of new toner (hatched area) supplied from toner pack 40 in this embodiment and old toner (filled in area) in developing container 32. These show how the new toner was actually inserted, as confirmed 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.

[0110] "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.

[0111] Figures 13(a) to 13(d) show the case where replenishment is performed when the tip position of the blade portion 34b is located farthest from the inlet 32c, while Figures 14(a) to 14(d) show the case where replenishment is performed when the tip position of the blade portion 34b is located on the inlet 32c side.

[0112] As shown in Figures 13(a) to 13(d), when the new toner is replenished when the tip position of the blade portion 34b is located at the farthest position from the inlet 32c at the time of replenishment, the new toner is discharged into a sufficiently wide space and falls to the bottom surface inside the developing container 32, spreading out in the longitudinal direction as if collapsing into a mountain.

[0113] However, on the other hand, as shown in Figures 14(a) to 14(d), if new toner is replenished when the tip position of the blade portion 34b is located on the inlet 32c side at the time of replenishment, the new toner will be ejected all at once into a narrow space, and will end up remaining at the protrusion 38 directly below the replenishment port 32a.

[0114] When the agitator 34 is driven, as shown in Figures 14(a) to 14(d), if the tip of the blade portion 34b is positioned on the inlet 32c side when the toner is replenished and the new toner remains near the inlet 32c in the longitudinal direction inside the developing container 32, it takes more than 20 seconds (20 rotations of the agitator 34) for the new toner to spread throughout the entire longitudinal area, even if the agitator 34 is driven.

[0115] 14(a) to 14(d), after 5 seconds (5 rotations of the agitator 34), the state in which new toner remains on the inlet 32c side has not been resolved, and there are areas with a high proportion of new toner (wavy line area). In this way, when there is a state in which there is a high proportion of new toner in the central area where the toner remaining amount sensor 50 is located, new toner adheres to the inner surfaces 612 and 622 of the light guide 600 on the developing container 32, reducing the accuracy of remaining amount detection. It is necessary to perform remaining amount detection after 20 seconds or more have elapsed, during which time new toner has spread over the entire longitudinal area, and this means that the user has to wait until the image forming apparatus 1 is ready for use after new toner has been replenished. cormorant.

[0116] Therefore, according to this embodiment, as shown in Figures 13(a) to 13(d), it is possible to replenish the toner when the tip of the blade portion 34b is located at the farthest position from the inlet 32c. Since the new toner instantly spreads in the longitudinal direction inside the developing container 32 immediately after replenishment, the new toner and the old toner become uniform in about 5 seconds (5 rotations of the stirring member 34). Since it is possible to prevent the new toner from adhering to the light guide 600 even at the 5-second mark, and the accuracy of remaining toner detection is unlikely to decrease, it is possible to shorten the time the user has to wait after replenishment.

[0117] In the configuration shown in this embodiment, only the configuration in which the blade portion 34b is provided on the stirring shaft 34a of the stirring member 34 has been shown, but the present invention is not limited to this.

[0118] For example, there is a configuration in which a cleaning member is installed in the longitudinal center to clean the remaining toner sensor 50. A cleaning member that is only located in the longitudinal center does not significantly block the space into which new toner is discharged when toner is replenished. Therefore, even in a configuration in which a cleaning member is provided, if the tip of the blade portion 34b is positioned away from the introduction port 32c before replenishment, new toner in the toner pack 40 is discharged into a sufficiently wide space during replenishment and enters the developing container 32 while spreading out in the longitudinal direction, thereby achieving the same effect as described above.

[0119] In addition, a T-seal for covering the developer opening 39 and sealing the toner in the toner storage chamber is configured to rotate along the agitator shaft 34a so that the toner does not leak during transportation of an unused image forming apparatus 1. The T-seal is, for example, a PET sheet having a thickness of about 45 um and an easy-peel film made of multi-layered polystyrene laminated thereon. The easy-peel film may be, for example, AE300 manufactured by Sumika Plastec Co., Ltd. The T-seal is wider in the longitudinal direction than the developer opening 39, and in an unused image forming apparatus 1, the easy-peel side surface completely covers the developer opening 39, sealing the toner in the developer container 32 so that it does not leak to the developer roller 31 or the supply roller 33 side.

[0120] The T-seal is attached to the agitation shaft 34a of the agitation 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 is taken up by the rotation of the agitation shaft 34a and peeled off from the developing opening 39. In this state, the T-seal is attached to the agitation shaft 34a of the agitation member 34 and rotates together with the blade portion 34b.

[0121] However, the T seal is thinner than the blade portion 34b and has a smaller elasticity, so it does not agitate the toner or send the toner to the development opening 39 like the blade portion 34b. Even if the tip of the T seal is located at the inlet 32c when new toner is replenished and the T seal is present in the path where the new toner enters the development container 32, the T seal falls due to the force of the new toner falling and does not hinder the entry of the new toner. In other words, even if the tip of the T seal is located at the inlet 32c, the new toner can spread and enter over the entire area in the longitudinal direction of the development container 32. In other words, even if the T seal is configured to rotate along the agitation shaft 34a, if the tip of the blade portion 34b is positioned away from the inlet 32c before replenishment, the new toner in the toner pack 40 is discharged into a sufficiently wide space during replenishment and spreads and enters the development container 32 in the longitudinal direction, so that the same effect as described above can be achieved.

[0122] In this way, members with various functions may be installed in the agitating member 34, but the same effect as described above can be achieved by positioning the tip of a member such as the blade portion 34b, which has high elasticity and has the function of agitating the toner and sending it to the development opening 39, away from the inlet 32c during replenishment.

[0123] Example 4 In the first to third embodiments, the means for adjusting the phase of the stirring member 34 and stopping it at a suitable phase has been described. However, in a configuration such as the image forming apparatus 1 described so far, the main motor 130, which is a single drive source common to each rotating member of the apparatus, continues to be driven during adjustment in the phase adjustment process P5, so the photosensitive drum 21 is also driven. Furthermore, configurations are known in which the voltage applied to the charging roller 22 and the like when the photosensitive drum 21 is stopped is switched over time, and in these configurations, there may be cases in which further consideration is required for the phase adjustment process P5.

[0124] Therefore, in the fourth embodiment, when executing the first stop control for stopping the rotation of the main motor 130 after the end of the image forming operation and the second stop control for stopping the application of the charging bias and the developing bias toward the stop timing of the motor rotation by the first stop control, the following control is performed. That is, the start timing of the second stop control is determined based on the deceleration time of the main motor 130 so that the end timings of the first stop control and the second stop control coincide with each other and the stirring member 34 stops at a predetermined rotation phase when the first stop control ends. The deceleration time of the main motor 130 is the time required for the rotation of the main motor 130 to completely stop after the power supply to the main motor 130 is stopped in the first stop control.

[0125] Here, before starting the first stop control (stopping the main motor 130), the rotation phase and rotation period of the stirring member 34 are determined, and the deceleration start timing of the main motor 130 is adjusted based on the rotation period of the stirring member 34. That is, the period of one rotation of the stirring member 34 is obtained based on the rotation phase of the stirring member 34 detected by the phase detection means (period acquisition process). Then, based on the obtained period of the stirring member 34 and the above-mentioned deceleration time, the start timing of the second stop control is obtained (adjustment process), and that is, the waiting time from the end of the stirring member period to the start of the second stop control is obtained, and the second stop control is started at the timing when the above-mentioned waiting time has elapsed from the end of the period.

[0126] In the second stop control (stopping application of bias, etc.), each bias application unit is controlled so that a predetermined potential difference is maintained between the photosensitive drum 21 and the developing roller 31 until the rotation of the main motor 130 stops. The predetermined potential difference is a potential difference that restricts the movement of toner from the developing roller 31 to the photosensitive drum 21. For example, while maintaining the potential difference between the charging bias and the developing bias applied in the image forming operation, the magnitudes of the charging bias and the developing bias are gradually decreased, and control is performed to stop the charging bias application unit and the developing bias application unit, respectively. In addition, before the rotation of the main motor 130 stops, after the developing bias becomes zero, the developing bias application unit applies a developing bias of a polarity opposite to the normal charging polarity of the toner, and continues application of the developing bias of the opposite polarity until the main motor 130 stops rotating.

[0127] In the second stop control (stopping application of bias, etc.), the pre-exposure device 23 continues to discharge the surface of the photosensitive drum 21 after the charging bias becomes zero, until one revolution of the circumferential surface of the photosensitive drum 21 is discharged. After the discharge of one revolution of the circumferential surface of the photosensitive drum 21 is completed, the pre-exposure device 23 is turned off, and then the power supply to the main motor 130 is stopped, that is, the first stop control is started.

[0128] 15 to 19, a description will be given of a means for linking the phase determination process P4, the phase adjustment process P5, and the high voltage operation when the motor is stopped in the fourth embodiment.

[0129] (Time relationship between phase determination process P4 and phase adjustment process P5) 15 is a timing chart showing the time relationship between the phase detection sensor 51 and the main motor 130, and between the phase determination process P4 and the phase adjustment process P5. While the rotor 30 is rotating at a steady speed, the phase detection sensor 51 periodically turns ON and OFF. In this embodiment, the stirring member 34 stops at a suitable phase angle when a predetermined phase angle has elapsed since the ON edge was detected.

[0130] At the start of the phase determination process P4, the phase detection sensor 51 starts detecting the ON edge at the start of the determination. This ON edge detection is the timing at which the phase detection sensor 51 first detects the pin 34d after the end of the image forming operation. When the ON edge is detected, it is confirmed whether the ON edge can be detected again one agitation period later, and it is determined that the first ON edge detection is not noise.

[0131] The phase adjustment process P5 may take over control from the phase determination process P4, or may operate independently. The phase adjustment process P5 starts edge detection based on the phase detected by the phase determination process P4. At this time, the edge detection section may be limited so as not to detect unnecessary noise. The control unit of the image forming apparatus instructs the main motor 130 to stop at a predetermined phase after edge detection.

[0132] At this time, taking into consideration the time T_stop that the main motor 130 takes to idle from when it starts to decelerate until it stops, and the phase angle at which the agitator 34 rotates during that time, a stop command is issued to the main motor 130 after T_wait from edge detection. This allows the agitator 34 to stop at a suitable phase angle. In other words, the second stop control can be started at a timing at which the rotation phase of the agitator falls within a predetermined range. The time required for phase adjustment in the phase adjustment process is T_all, which is the sum of T_stop and T_wait from the edge detection.

[0133] (Explanation of high-voltage module configuration and shutdown process in embodiment 4) FIG. 16 is a diagram showing the positional relationship of parts arranged around the photosensitive drum 21 of the image forming apparatus 1. A pre-exposure device 23 is arranged above the photosensitive drum 21, and it removes the surface potential of the photosensitive drum 21 before charging. A charging roller 22 is arranged downstream of the pre-exposure device 23, and it applies a charging bias to uniformly charge the photosensitive drum 21. The irradiation position of the pre-exposure device 23 is upstream of the charging roller 22, and the light of the pre-exposure device 23 does not reach downstream of the charging roller 22. A developing roller 31 is arranged at a point located downstream of the charging roller 22 by a phase angle θ, and a developing bias is applied so that the developer carried by the developing roller 31 does not flow out to the photosensitive drum 21. In order to prevent the developer from flowing out to the photosensitive drum 21, it is necessary to control the relationship between the charging bias at the nip N between the developing roller 31 and the photosensitive drum 21, the developing bias, and the potential of the developer due to the friction between the developing roller 31 and the developing blade 35 to be constant.

[0134] FIG. 17 is a block diagram showing the relationship between the various components and the control unit described with reference to FIGS.

[0135] The main control unit 100 includes a phase control unit 110 and an image formation control unit 120.

[0136] The phase control unit 110 includes a phase detection unit 111 that controls the phase determination process P4, and a phase adjustment unit 112. The phase detection unit 111 detects the phase angle by phase detection means 113. The phase detection means 113 detects the phase by the input of the phase detection sensor 51. Like the phase detection unit 111, the phase adjustment unit 112 adjusts the phase angle of the stirring member 34 by controlling the stirring drive control means 114 based on the input of the phase detection means 113. In this embodiment, the stirring drive control means 114 is connected to the main motor 130.

[0137] On the other hand, the image formation control unit 120 includes a high voltage stop control unit 121. The high voltage stop control unit 121 includes a stop drive control unit 122, which controls the main motor 130 in this embodiment. The high voltage stop control unit 121 also includes a pre-exposure control unit 123, a charging control unit 124, and a development control unit 125, which are connected to the pre-exposure device 23, the charging roller 22, and the developing roller 31, respectively. The pre-exposure control unit 123 switches the exposure of the pre-exposure device 23 ON (lighting) / OFF (lighting out) in response to a command from the high voltage stop control unit 121. The charging control unit (charging bias application unit) 124 controls the application of a charging bias to the charging roller 22 from a high voltage power source (not shown) in response to a command from the high voltage stop control unit 121. The development control unit (developing bias application unit) 125 controls the application of a developing bias to the developing roller 31 from a high voltage power source (not shown) in response to a command from the high voltage stop control unit 121.

[0138] A method of stopping high voltage stop control section 121 using the above control means will be described with reference to Fig. 18. Fig. 18 is a timing chart showing the stop control of high voltage stop control section 121.

[0139] Before the motor is stopped, the main motor 130 is rotating at a steady rate, the pre-exposure device 23 is turned on, and the charging control unit 124 and the developing control unit 125 output a negative potential during image formation. This state is the optimum state for preventing developer outflow while the main motor 130 is running, and it is preferable to maintain this state as much as possible until the motor is stopped.

[0140] When the high voltage stop control unit 121 receives an instruction to end the image forming operation, it starts decreasing the potential of the charging control unit 124. At this time, the width of the decrease is determined so that the potential difference between the charging bias and the developing bias becomes equal to or less than a predetermined potential in the developing nip D. Although an example of decreasing in three stages is shown in FIG. 18, control may be performed with fewer or more stages.

[0141] Next, the development control unit 125 starts to lower the development bias after waiting for T_PrDv from the completion of the fall of the charging bias. T_PrDv can be calculated from the phase angle θ of charging and development, the distance between the charging and development nip calculated from the diameter of the photosensitive drum 21, and the target speed at which the image forming operation was driven. The charging control unit 124 and the development control unit 125 repeat the above operation, and the charging control unit 124 outputs 0V and the development control unit 125 outputs a positive potential, that is, a potential of a polarity opposite to the normal charging polarity of the toner. This setting is merely an example, and for example, the set potential of the charging control unit 124 may be a predetermined potential or less at which the potential of the charging bias is not applied to the photosensitive drum 21.

[0142] After the potential applied by the charging control unit 124 has completely fallen, the pre-exposure control unit 123 waits until the time T_Dr required for complete neutralization of the photosensitive drum 21 for one rotation of the drum has elapsed, and then stops the pre-exposure device 23. After the pre-exposure device 23 has been turned off, the high voltage stop control unit 121 issues a stop command to the main motor 130. After the main motor 130 has completely stopped, the development control unit 125 stops outputting the positive potential, and the stop control of the high voltage stop control unit 121 is completed. As described above, it takes a time of T_Seq from the start of the fall of the charging control unit 124 to the development control unit 125 issuing a stop command for the positive potential to be output for the high voltage stop control unit 121 to completely stop.

[0143] 15 and 18, the control of the phase adjustment process P5 and the stop control of the high voltage stop control unit 121 are both controls with time constraints for stopping the main motor 130. A method of performing these two controls in parallel will be described.

[0144] Fig. 19 is a timing chart illustrating the operation of concurrently performing the phase adjustment process P5 and the stop control of the high voltage stop control unit 121. The relationship between the phase determination process P4 and the phase adjustment process P5 and the phase detection sensor 51 is the same as in Fig. 15, and therefore is not illustrated in Fig. 19.

[0145] The phase determination process P4 detects the edge detection as described in FIG. 15 and determines the period. The phase adjustment process P5 performs edge detection based on the detection result of the phase determination process P4 and starts phase alignment. At this time, the phase alignment waiting time T_wait is controlled so as to wait for the start of the stop control of the high voltage stop control unit 121, rather than waiting for the start of the stop of the main motor 130 as shown in FIG. 15. At this time, the photosensitive drum 21 rotates at the speed of the image forming operation for an amount obtained by subtracting the time T_Stop required for the deceleration to stop of the main motor 130 from the time T_Seq required for the stop control of the high voltage stop control unit 121. When performing phase alignment at the start of the stop control of the high voltage stop control unit 121, the phase adjustment process P5 can calculate the phase that the stirring member 34 advances from the above-mentioned time difference, and can obtain the phase alignment time T_wait.

[0146] Example 5 In the fifth embodiment, the operation of the phase adjustment process P5 in the case where there are multiple stop processes will be described in addition to the relationship between the high voltage stop process and the phase adjustment process P5 shown in the fourth embodiment. The time relationship between the phase determination process P4 and the phase adjustment process P5, and the high voltage module configuration and the stop process are the same as those in the fourth embodiment, so the description will be omitted.

[0147] 20 shows a second stopping method of the high voltage in the fourth embodiment. The stopping method in this embodiment is a stopping process that is performed after a cleaning process (cleaning control) is performed, for example, in a process at the time of stopping image formation. An example of the cleaning process is cleaning that aims to transfer the developer attached to the charging roller 22 back to the developing roller 31 via the photosensitive drum 21. Specifically, from a state in which the photosensitive drum 21 is uniformly charged, the potential applied to the charging roller 22 is turned ON / OFF at a predetermined cycle to transfer the negative developer attached to the charging roller 22 to the photosensitive drum 21. Then, the negative developer transferred to the photosensitive drum 21 is transferred back to the developing roller 31 to which a positive potential is applied.

[0148] Due to the immediately preceding cleaning, the charging control unit 124 holds a lower potential than during the image forming process, and the pre-exposure device 23 is turned off. The development control unit 125 outputs a positive potential. That is, at the start of the second stop control, the charging bias is lower than the charging bias applied during the image forming operation, and the development bias is a development bias of a polarity opposite to the normal charging polarity of the toner.

[0149] At the start of the stop process, the pre-exposure device 23 turns on, and the charging control unit 124 stops applying voltage. After waiting for the time T_Dr required for the photosensitive drum 21 to rotate once from the time the charging control unit 124 stops applying voltage, the pre-exposure device 23 turns off. At the same time, a stop command is issued to the main motor 130, and after waiting for the main motor 130 to stop, the development control unit 125 turns off the output of the positive polarity potential. The period T_Seq2 from the start of the stop control to the time the development control unit 125 turns off the output of the positive polarity potential is a different time from T_Seq in FIG. 18.

[0150] 21 is a flow chart for determining the adjustment time of the phase adjustment process P5 in the fifth embodiment. When post-processing of image formation is started, the image formation control unit 120 selects and executes the necessary post-processing (1601). The processing of the phase determination process P4 is omitted since it is the same as that described in the fourth embodiment. Depending on the selection of this post-processing, it is determined whether the stop processing required when stopping the main motor 130 is the first stop processing or the second stop processing (1602).

[0151] When performing the first stop processing, the adjustment time that the phase adjustment process P5 should take into consideration is, as described in the fourth embodiment, the time T_Seq required for the first stop control minus the time T_Stop required for deceleration and stopping of the main motor 130 (1603).

[0152] Furthermore, when the stop process performs the second stop control, the adjustment time to be taken into consideration by the phase adjustment process P5 is the time T_Seq2 required for the second stop control minus the time T_Stop required for the main motor 130 to decelerate and stop (1604).

[0153] A phase alignment time (adjustment time) T_wait is calculated so that the calculated time is the smallest integral multiple of one agitation period of the agitator 34 (1605), and a phase adjustment process P5 is performed in accordance with T_wait (1606). After completing the phase adjustment process P5, the main control unit 100 performs a necessary stop process (1607).

[0154] By controlling as described above, even if there are multiple stop processes, it is possible to stop the main motor 130 while appropriately matching the phase of the stirring member 34 at the time of stopping. Note that the stop processes described above are not limited to the processes described in this embodiment, and may include different stop processes, or may include a third and fourth stop process. Even if there are three or more stop processes, the effect described in this embodiment can be obtained by calculating the time required for each stop process and calculating the adjustment time T_wait of the phase adjustment process according to that time.

[0155] Example 6 In the sixth embodiment, a calculation method of the adjustment time of the phase adjustment process P5 described in the fourth and fifth embodiments will be described, and further a calculation method of the adjustment time of the phase adjustment process P5 in a case where the image formation control unit 120 extends the post-processing will be described. In the sixth embodiment, while the post-processing is being performed as an adjustment operation of the device, the period of one rotation of the stirring member 34 is obtained (period obtaining process) and the stop timing of the main motor 130 is obtained (adjustment process).

[0156] Fig. 22 is a timing chart showing the time relationship when the image formation control unit 120 extends the post-processing in addition to the time relationship between the phase adjustment process and the stop control shown in Fig. 19. The image formation control unit 120 may also perform the post-processing including the cleaning operation as described in the fifth embodiment after the image forming operation. Also, for example, when a narrow recording material is conveyed, the post-processing is extended in order to make the temperature rise at the end of the fixing unit 70 uniform.

[0157] In the phase adjustment process P5, the main control unit 100 calculates the phase adjustment time T_wait from the time T_Seq required for the stop processing of the image formation control unit 120. When the extension of the post-processing of the image formation control unit 120 is completed, in the phase adjustment process P5, the main control unit 100 performs phase alignment based on the elapsed time T_over from the previous detection by the phase detection means 113, and instructs the image formation control unit 120 to start the stop processing.

[0158] FIG. 23 is a flow chart for explaining the process of FIG. 22 in detail. The same explanation as that explained in the fifth embodiment will be omitted. When the image forming control unit 120 starts post-processing (2001), it detects the phase in the phase determination process P4. Then, it judges whether the post-processing is completed (2002). If it is not completed, it checks the detection of the reference phase by the phase detection means 113 (2003). If it is detected, it updates the most recent detection time T_latest (2004). When the post-processing is completed, the main control unit 100 calculates T_over as the elapsed time from the time T_latest when the most recent reference phase was detected (2005). Then, it judges whether T_over is longer than T_wait (2006), and if it is longer, it detects the reference phase again (2007). When the reference phase is detected, it updates T_latest and then updates T_over again (2008). If T_over is less than T_wait, the phase adjustment process P5 returns to updating T_over (2009). If T_over and T_wait become equal, the main control unit 100 instructs the image formation control unit 120 to start a stop process.

[0159] By controlling in the manner described above, even if post-processing is extended, it is possible to minimize the time for which drive is extended by phase adjustment, and to adjust the phase by shutting down the main motor 130 while suppressing image damage by the stop process.

[0160] In this embodiment, the factor for extending the post-processing is described as a process for uniformly increasing the temperature at the end of the fixing unit 70, but the configuration of this embodiment is not limited to this. For example, it may be selected to wait for the completion of a process for detecting the remaining amount of developer, or to wait for the longest factor among the above-mentioned several extension processes.

[0161] The configurations and control methods of the above-described embodiments can be combined with each other as much as possible.

[0162] The disclosure of the embodiments of the present invention includes the following configurations. (Configuration 1) An image forming apparatus to which a toner container can be attached, A rotating photosensitive drum; a charging roller that rotates in contact with the surface of the photosensitive drum; a charging bias applying unit that applies a charging bias to the charging roller; a developing roller that carries a developer and rotates to supply toner to the photosensitive drum; a developing bias applying section that applies a developing bias to the developing roller; a mounting portion into which the toner container can be mounted so that a portion of the toner container is exposed to the outside of the image forming apparatus, the mounting portion being provided with a refill port through which toner is replenished in the toner container; a frame having a developing chamber in which the developing roller is disposed, and a storage chamber in which toner is stored and which is connected to the developing chamber and has a storage chamber opening that can communicate with the supply port; The stirring member is provided in the storage chamber, and includes a rotating shaft that rotates around a rotation axis, a first end that is one end in a direction perpendicular to the rotation axis, and a second end that is a sheet having a second end that is capable of contacting an inner wall of the toner storage chamber, the agitating member rotating to agitate the toner stored in the toner storage chamber; a phase detection means for detecting a rotation phase of the stirring member; a single motor for supplying driving forces for rotating the photosensitive drum, the charging roller, the developing roller, and the stirring member; a control unit that controls the charging bias application unit, the developing bias application unit, and the motor; Equipped with an image forming apparatus which executes a first stop control for stopping the rotation of the motor after an image forming operation is completed, and a second stop control for stopping bias application by the charging bias application unit and the developing bias application unit toward a timing at which the rotation of the motor is stopped by the first stop control, The image forming apparatus is characterized in that the control unit starts the second stop control after a waiting time has elapsed from the detection timing based on the rotation phase of the stirring member detected at the detection timing after the end of the image forming operation and the time required for the second stop control, so that the rotation phase of the stirring member at the stop timing is within a predetermined range. (Configuration 2) The control unit is Before starting the first stop control, a period acquisition process for acquiring a period of one rotation of the stirring member based on the rotation phase detected by the phase detection means; an adjustment process of acquiring a start timing of the second stop control based on the period acquired in the period acquisition process and the deceleration time; The image forming apparatus according to configuration 1, (Configuration 3) the second stop control is started after the image forming operation is completed and an adjustment operation of the device is performed, 3. The image forming apparatus according to claim 2, wherein the period acquisition process and the adjustment process are executed during the execution of the adjustment operation. (Configuration 4) The image forming apparatus according to any one of configurations 1 to 3, characterized in that the second stop control is a control for stopping the charging bias application unit and the developing bias application unit while maintaining a potential difference between the image carrier and the developer carrier that regulates the movement of the developer from the developer carrier to the image carrier until the first stop control is terminated. (Configuration 5) In the second stop control, The image forming apparatus according to any one of configurations 1 to 4, characterized in that the charging bias application unit and the developing bias application unit gradually reduce the magnitude of the charging bias and the developing bias, respectively, while maintaining the potential difference between the charging bias and the developing bias applied during the image forming operation. (Configuration 6) In the second stop control, The image forming apparatus according to any one of configurations 1 to 5, characterized in that after the developing bias becomes zero, the developing bias application unit applies a developing bias of a polarity opposite to the normal charging polarity of the developer, and continues applying the developing bias of the opposite polarity until the motor stops rotating. (Configuration 7) the charging bias is lower than the charging bias applied in the image forming operation at the start of the second stop control, the developing bias is a developing bias having a polarity opposite to a normal charging polarity of the developer at the start of the second stop control, 7. The image forming apparatus according to any one of configurations 1 to 6, wherein the developing bias application section continues to apply the developing bias of the opposite polarity until the motor stops rotating. (Configuration 8) The image forming apparatus according to any one of configurations 1 to 7, characterized in that the second stop control is started after a cleaning control is performed after an image forming operation is completed, in which the developer adhering to the charging member is transferred again to the developer carrier via the image carrier. (Configuration 9) a charge removing unit that removes charge from the surface of the image carrier before the surface is charged by the charging member to which the charging bias is applied, In the second stop control, the charge removing unit continues removing the charge from the surface of the image carrier until one revolution of the circumferential surface of the image carrier is removed after the charging bias becomes zero, 9. The image forming apparatus according to any one of configurations 1 to 8, wherein the control unit stops the supply of current to the motor after the static electricity removal unit stops removing static electricity. (Configuration 10) The stirring member is A rotating member provided inside the developer storage chamber; a sheet attached to the rotating member, the sheet having an end portion remote from the attachment portion to the rotating member capable of contacting an inner wall of the developer accommodating chamber; having The frame body is a developer receiving port for receiving a supply of developer from a developer supply container to the developer storage chamber; a developer inlet opening in an inner wall of the developer storage chamber for supplying the developer received through the developer receiving port to the developer storage chamber; having the developer inlet is located in a first quadrant or a second quadrant in a coordinate system defined by an axis along a horizontal direction and an axis along a gravity direction, the axes intersecting at a rotation center of the rotation member when viewed in a direction of a rotation axis of the rotation member; An image forming apparatus according to any one of configurations 1 to 9, characterized in that the specified rotational phase in which the stirring member is positioned when the first stop control is terminated is a rotational phase in which the end of the sheet is positioned in a quadrant different from the quadrant in which the developer inlet is positioned in the coordinate system. (Configuration 11) The image forming apparatus according to any one of configurations 1 to 10, characterized in that the control unit controls the rotating member so that, in the coordinate system, when the developer inlet is located in the first quadrant, the end of the sheet is located in the third quadrant. (Configuration 12) 12. The image forming apparatus according to any one of configurations 1 to 11, wherein the control unit controls the rotating member so that, when the developer inlet is located in the first quadrant, the edge of the sheet is located in the second quadrant or the fourth quadrant in the coordinate system. [Explanation of symbols]

[0163] 1... image forming apparatus, 21... photosensitive drum (image carrier), 31... developing roller (developer carrier), 32... developing container, 32a supply port (developer receiving port), 32c... introduction port (developer introduction port), 32d... toner storage chamber (developer storage chamber), 34... stirring member, 34a... stirring shaft, 34b... blade portion, 39... developing opening, 40... supply container (toner pack)

Claims

1. An image forming apparatus to which a toner container can be attached, A rotating photosensitive drum; a charging roller that rotates in contact with the surface of the photosensitive drum; a charging bias applying unit that applies a charging bias to the charging roller; a developing roller that carries a developer and rotates to supply toner to the photosensitive drum; a developing bias applying section that applies a developing bias to the developing roller; a mounting portion into which the toner container can be mounted so that a portion of the toner container is exposed to the outside of the image forming apparatus, the mounting portion being provided with a refill port through which toner is replenished in the toner container; a frame having a developing chamber in which the developing roller is disposed, and a storage chamber in which toner is stored and which is connected to the developing chamber and has a storage chamber opening that can communicate with the supply port; The stirring member is provided in the storage chamber, and includes a rotating shaft that rotates around a rotation axis, a first end that is one end in a direction perpendicular to the rotation axis, and a second end that is a sheet having a second end that is in contact with an inner wall of the toner storage chamber, the sheet rotating to agitate the toner stored in the toner storage chamber; a phase detection means for detecting a rotation phase of the stirring member; a single motor for supplying driving forces for rotating the photosensitive drum, the charging roller, the developing roller, and the stirring member; a control unit that controls the charging bias application unit, the developing bias application unit, and the motor; Equipped with an image forming apparatus which executes a first stop control for stopping the rotation of the motor after an image forming operation is completed, and a second stop control for stopping bias application by the charging bias application unit and the developing bias application unit toward a timing at which the rotation of the motor is stopped by the first stop control, The control unit starts the second stop control after a waiting time has elapsed from the detection timing so that the rotational phase of the stirring member at the stop timing is within a predetermined range of rotational phase based on the rotational phase of the stirring member detected at the detection timing after the end of the image forming operation and the time required for the second stop control.

2. The control unit is Before starting the first stop control, a period acquisition process for acquiring a period of one rotation of the stirring member based on the rotation phase detected by the phase detection means; an adjustment process for acquiring the waiting time based on the period acquired in the period acquisition process and a time required for the second stop control; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus executes the steps of:

3. the second stop control is started after the image forming operation is completed and an adjustment operation of the device is performed, The image forming apparatus according to claim 2 , wherein the periodic acquisition process and the adjustment process are executed during the execution of the adjustment operation.

4. The image forming apparatus according to claim 2, characterized in that the second stop control is a control that stops the charging bias application unit and the developing bias application unit while maintaining a potential difference between the photosensitive drum and the developing roller that regulates the movement of toner from the developing roller to the photosensitive drum until the first stop control is completed.

5. In the second stop control, 5. The image forming apparatus according to claim 4, wherein the charging bias application unit and the developing bias application unit gradually reduce the magnitude of the charging bias and the developing bias, respectively, while maintaining the potential difference between the charging bias and the developing bias applied during the image forming operation.

6. In the second stop control, 6. The image forming apparatus according to claim 5, wherein the developing bias application unit applies a developing bias having a polarity opposite to the normal charging polarity of the toner after the developing bias becomes zero, and continues to apply the developing bias having the opposite polarity until the motor stops rotating.

7. the charging bias is lower than the charging bias applied in the image forming operation at the start of the second stop control, the developing bias is a developing bias having a polarity opposite to a normal charging polarity of the toner at the start of the second stop control, 5. The image forming apparatus according to claim 4, wherein the developing bias application section continues to apply the developing bias of the opposite polarity until the motor stops rotating.

8. 8. The image forming apparatus according to claim 7, wherein the second stop control is initiated after a cleaning control is performed in which the toner adhering to the charging roller is transferred back to the developing roller via the photosensitive drum after the image forming operation is completed.

9. a charge removing unit that removes charge from the surface of the photosensitive drum before the surface is charged by the charging roller to which the charging bias is applied, In the second stop control, the charge removing means continues removing electricity from the surface of the photosensitive drum after the charging bias becomes zero until one revolution of the circumferential surface of the photosensitive drum is removed, 5. The image forming apparatus according to claim 4, wherein the control unit stops the supply of electricity to the motor after the charge removal unit stops removing electricity.

10. When viewed in the direction of the rotation axis, in a two-dimensional coordinate system formed by a first virtual line passing through the rotation axis and extending in a horizontal direction, and a second virtual line passing through the rotation axis and extending in a gravity direction, at least a portion of the storage chamber opening is located in a first quadrant or a second quadrant, 2. An image forming apparatus according to claim 1, wherein the position where the second end of the sheet is located at the end of the first stop control is included in a quadrant in the coordinate system different from the quadrant where the storage chamber opening is located.

11. the chamber opening is disposed in the first quadrant of the coordinate system when viewed in the direction of the rotation axis; The image forming apparatus according to claim 10, characterized in that the control unit starts the first stop control and the second stop control after the waiting time has elapsed so that the second end of the sheet is stopped in the third quadrant when the first stop control ends.

12. the chamber opening is disposed in the first quadrant of the coordinate system when viewed in the direction of the rotation axis; The image forming apparatus according to claim 10, characterized in that the control unit starts the first stop control and the second stop control after the waiting time has elapsed so that the second end of the sheet is stopped in the second quadrant or the fourth quadrant when the first stop control ends.

13. The end timing of the first stop control and the end timing of the second stop control coincide with each other.

2. The image forming apparatus according to claim 1,

14. 2. The image forming apparatus according to claim 1, wherein, in the second stop control, application of the developing bias by the developing bias application section is terminated after application of the charging bias by the charging bias application section is terminated.

Images