Image forming apparatus

Abstract

To provide an image forming apparatus that can efficiently remove a toner accumulated on a developing device to more surely prevent an image defect caused by the toner.SOLUTION: An image forming apparatus comprises: a developing device 412 that attaches toner to a latent image, with a toner carrier (developing roller 204) arranged opposite to a latent image carrier (photoreceptor drum 413) on which the latent image is formed, to develop the latent image; a pressing and separation mechanism 416 that presses the developing device 412 against the latent image carrier or separates the developing device 412 from the latent image carrier; an excitation mechanism (drive transmission member 214) that applies vibration to a housing (developer housing 201) of the developing device 412; and a first control unit (control unit 100) that controls the pressing and separation mechanism 416 and the excitation mechanism. The first control unit causes the pressing and separation mechanism 416 to separate the developing device 412 from the latent image carrier and subsequently causes the excitation mechanism to vibrate the housing of the developing device 412.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] An image forming apparatus using electrophotographic process technology charges the surface of a photosensitive drum, which is a latent image carrier, using a charging device. Next, the image forming apparatus forms an electrostatic latent image on the surface of the photosensitive drum by irradiating the photosensitive drum with laser light based on image data. Next, the image forming apparatus visualizes the electrostatic latent image by supplying developer to the photosensitive drum using a developing device, forming a toner image on the photosensitive drum. Next, the image forming apparatus transfers and fixes the toner image onto paper, thereby forming an image on the paper.

[0003] In such an image forming apparatus, toner that has adhered and accumulated on the developing device falls onto the photosensitive drum during image formation and is then transferred to the transfer belt, which can cause image defects such as image smearing on the printed matter.

[0004] To address this problem, Patent Documents 1 to 3 disclose image forming apparatuses equipped with a vibration unit that applies vibration to the housing of the developing device. According to the configurations described in Patent Documents 1 to 3, toner accumulated in the developing device can be dropped and removed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 09-211974 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-099239 [Patent Document 3] Patent Publication No. 2021-184038 Summary of the Invention [Problem to be solved by the invention]

[0006] Generally, the developing device is positioned while being pressed against the photosensitive unit. Therefore, even when the housing of the developing device is vibrated by the vibrating means described in Patent Documents 1 to 3, the amplitude of the vibration is suppressed. Therefore, there is a problem that the toner cannot be removed efficiently.

[0007] SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can efficiently remove toner accumulated in a developing device and more reliably prevent image defects caused by toner. [Means for solving the problem]

[0008] The invention described in claim 1 has been made to achieve the above object, a developing device that develops a latent image by attaching toner to the latent image via a toner carrier disposed opposite a latent image carrier on which the latent image is formed; a pressing / separating mechanism that presses the developing device against the latent image carrier or separates the developing device from the latent image carrier; a vibration mechanism that applies vibration to a housing of the developing device; a first control unit that controls the separation mechanism and the vibration mechanism; Equipped with The first control unit separates the developing device from the latent image carrier using the pressing mechanism, and then vibrates the housing of the developing device using the vibration mechanism.

[0009] The invention described in claim 2 is the image forming apparatus described in claim 1, the developing device includes a drive transmission member that transmits a drive force to a toner transport member that transports the toner; the vibration mechanism is the drive transmission member, The drive transmission member switches between a first operation of transmitting the drive force to the toner transport member to transport the toner, and a second operation of vibrating a prevention member provided in the developing device to prevent the toner from scattering.

[0010] The invention described in claim 3 is the image forming apparatus described in claim 2, The first control unit switches the rotation direction of the drive transmission member to cause the drive transmission member to switch between the first operation and the second operation.

[0011] The invention described in claim 4 is the image forming apparatus described in claim 3, The first control unit is by rotating the drive transmission member in a first direction in a state in which an engaged portion of the drive transmission member and an engaging portion of the toner transport member are engaged with each other, the drive transmission member transmits a drive force greater than a rotational load of the toner transport member to the toner transport member as the first operation, and the toner transport member is rotated in the first direction to transport the toner; The drive transmission member is rotated in a second direction that is opposite to the first direction, and the drive transmission member is caused to perform the second operation while the rotation of the toner transport member is stopped.

[0012] The invention described in claim 5 is the image forming apparatus described in claim 4, The toner transport member includes a regulating member that regulates the toner transport member so that the toner transport member does not rotate in the second direction when the drive transmission member rotates in the second direction.

[0013] The invention described in claim 6 is the image forming apparatus described in claim 2, The drive transmission member transmits the driving force to the toner transport member via an engaged portion of the drive transmission member, which is in an engaged state in the first operation, and an engaging portion of the toner transport member.

[0014] The invention described in claim 7 is the image forming apparatus described in claim 6, The drive transmission member is displaceable along the axial direction of the toner transport member, and performs the second operation when displaced from a position in which the engagement between the engaged portion and the engaging portion is released to a position in which the engagement between the engaged portion and the engaging portion is engaged.

[0015] The invention described in claim 8 is the image forming apparatus described in claim 2, the developing device includes an elastic member, The drive transmission member performs the second movement by utilizing the elastic force of the elastic member.

[0016] The invention described in claim 9 is the image forming apparatus described in claim 2, a detection unit that detects a rotation load of the toner transport member; a second control unit that does not restrict rotation of the toner transport member when the rotation load detected by the detection unit is greater than a predetermined value, and restricts rotation of the toner transport member when the rotation load is equal to or less than the predetermined value; Equipped with.

[0017] The invention described in claim 10 is the image forming apparatus described in claim 2, The toner transport member is connected to the prevention member via a rigid body.

[0018] The invention described in claim 11 is the image forming apparatus described in claim 2, The second operation is performed simultaneously with an operation different from the second operation performed by the image forming apparatus. [Effects of the Invention]

[0019] According to the present invention, toner accumulated in the developing device can be efficiently removed, and image defects caused by toner can be more reliably prevented. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] 1 is a block diagram showing a functional configuration of an image forming apparatus according to an embodiment of the present invention; [Figure 3] FIG. 2 is a schematic side view of the developing device according to the embodiment; [Figure 4] FIG. 2 is a schematic diagram of the vicinity of the developing device according to the embodiment, as viewed from above. [Figure 5] FIG. 2 is a diagram illustrating an example of a state in which the developing device is separated from the photosensitive drum. [Figure 6] 4 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a first direction. FIG. [Figure 7] 7 is a schematic diagram showing the positional relationship between the drive transmission member and the end of the engagement portion when viewed from the negative direction of the X axis in the state of FIG. 6. FIG. [Figure 8] FIG. 2 is a schematic view of a drive transmission member. [Figure 9] 10 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a second direction. FIG. [Figure 10] 10 is a schematic diagram showing the positional relationship between the drive transmission member and the end of the engagement portion when viewed from the negative direction of the X axis in the state of FIG. 9. FIG. [Figure 11] 10 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a second direction. FIG. [Figure 12] 12 is a schematic diagram showing the positional relationship between the drive transmission member and the end of the engagement portion when viewed from the negative direction of the X axis in the state shown in FIG. 11. FIG. [Figure 13] 10 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a second direction. FIG. [Figure 14] 14 is a schematic diagram showing the positional relationship between the drive transmission member and the end of the engagement portion when viewed from the negative direction of the X axis in the state of FIG. 13. FIG. [Figure 15] 10 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a second direction. FIG. [Figure 16] 16 is a schematic diagram showing the positional relationship between the drive transmission member and the end of the engagement portion when viewed from the negative direction of the X axis in the state shown in FIG. 15. FIG. [Figure 17] 10 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a second direction. FIG. [Figure 18] 18 is a schematic diagram showing the positional relationship between the drive transmission member and the end of the engagement portion when viewed from the negative direction of the X axis in the state of FIG. 17. FIG. [Figure 19] 10 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a second direction. FIG. [Figure 20]20 is a schematic diagram showing the positional relationship between the drive transmission member and the end of the engagement portion when viewed from the negative direction of the X axis in the state of FIG. 19. FIG. [Figure 21] FIG. 10 is a diagram illustrating the effect of the second operation. [Figure 22] FIG. 11 is a schematic view of the vicinity of a developing device according to a second embodiment, as viewed from above. [Figure 23] FIG. 10 is a block diagram showing a control function in a rotation restricting operation according to a modified example of the second embodiment. [Figure 24] FIG. 11 is a schematic view of the vicinity of a developing device according to a modified example of the second embodiment, as viewed from above. [Figure 25] FIG. 11 is a schematic perspective view of the vicinity of a solenoid and a protruding member according to a modified example of the second embodiment. [Figure 26] 10 is a flowchart of a rotation control process according to a modified example of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] The present embodiment will be described in detail below with reference to the drawings, but the scope of the invention is not limited to the illustrated examples.

[0022] <1. Configuration of Image Forming Apparatus 1> Fig. 1 is a diagram schematically showing the overall configuration of an image forming apparatus 1 according to an embodiment of the present invention, and Fig. 2 is a block diagram showing the main functional configuration of the image forming apparatus 1 according to the embodiment. 1 and 2 is an intermediate transfer type color image forming apparatus that utilizes electrophotographic process technology. The image forming apparatus 1 transfers (primary transfer) toner images of each color, Y (yellow), M (magenta), C (cyan), and K (black), formed on a photosensitive drum 413, onto an intermediate transfer belt 421. Next, the image forming apparatus 1 overlays the four color toner images on the intermediate transfer belt 421, and then transfers them onto paper S (secondary transfer), thereby forming an image.

[0023] The image forming apparatus 1 is of a tandem type in which photosensitive drums 413 corresponding to the four colors YMCK are arranged in series in the running direction of an intermediate transfer belt 421, and toner images of each color are transferred onto the intermediate transfer belt 421 in sequence.

[0024] As shown in FIG. 2, the image forming apparatus 1 includes an image reading unit 10, an operation display unit 20, an image processing unit 30, an image forming unit 40, a paper conveying unit 50, a fixing unit 60, a memory unit 70, a communication unit 80, and a control unit 100.

[0025] The control unit 100 includes a CPU 101, a ROM 102, a RAM 103, and the like. The CPU 101 reads out a program corresponding to the processing content from the ROM 102, loads it into the RAM 103, and centrally controls the operations of the blocks of the image forming apparatus 1 shown in FIG. 2 in cooperation with the loaded program.

[0026] The image reading unit 10 includes an automatic document feeder 11 called an ADF (Auto Document Feeder), a document image scanning device 12, and the like. The automatic document feeder 11 transports the documents D placed on the document tray using a transport mechanism and sends them to the document image scanning device 12. The automatic document feeder 11 can continuously read the images of multiple documents D placed on the document tray all at once.

[0027] The document image scanning device 12 optically scans a document transported from the automatic document feeder 11 onto the contact glass or a document placed on the contact glass. Next, the document image scanning device 12 forms an image of the light reflected from the document on the light receiving surface of a CCD (Charge Coupled Device) sensor 12a, thereby reading the document image. The image reading unit 10 generates input image data based on the reading result by the document image scanning device 12. The image processing unit 30 performs predetermined image processing on the input image data.

[0028] The operation display unit 20 includes, for example, a liquid crystal display (LCD) with a touch panel, and functions as a display unit 21 and an operation unit 22. The display unit 21 displays various operation screens, image status displays, operation statuses of various functions, etc., in accordance with a display control signal input from the control unit 100. The operation unit 22 includes various operation keys such as a numeric keypad and a start key, and receives various input operations from the user and outputs operation signals to the control unit 100.

[0029] The image processing unit 30 includes a circuit and the like that performs digital image processing on the image data of the input job (input image data) according to initial settings or user settings. For example, the image processing unit 30 performs gradation correction based on gradation correction data under the control of the control unit 100. The image processing unit 30 performs various correction processes, such as color correction and shading correction, compression, etc., on the input image data in addition to gradation correction.

[0030] The image forming unit 40 forms an image using color toners of Y, M, C, and K components based on input image data that has been image-processed by the image processing unit 30. The image forming section 40 includes image forming units 41Y, 41M, 41C, and 41K, an intermediate transfer unit 42, and the like.

[0031] The image forming units 41Y, 41M, 41C, and 41K for the Y, M, C, and K components have the same configuration. For ease of illustration and explanation, common components are denoted by the same reference numerals, and when distinguishing between them, the reference numerals are suffixed with Y, M, C, or K. In Figure 1, only the components of the image forming unit 41Y for the Y component are denoted by reference numerals, and the components of the other image forming units 41M, 41C, and 41K are not denoted by reference numerals.

[0032] The image forming unit 41 includes an exposure device 411, a developing device 412, a photosensitive drum 413, a charging device 414, a drum cleaning device 415, and the like.

[0033] The photosensitive drum 413 is an organic photosensitive body in which a photosensitive layer made of a resin containing an organic photoconductor is formed on the outer peripheral surface of a drum-shaped metal substrate, for example. The photosensitive drum 413 functions as a latent image carrier. The control unit 100 controls the drive current supplied to a drive motor (not shown) that rotates the photosensitive drum 413, thereby rotating the photosensitive drum 413 at a constant peripheral speed.

[0034] The charging device 414 is, for example, a charger, and generates a corona discharge to uniformly charge the surface of the photoconductive photosensitive drum 413 to a negative polarity.

[0035] The exposure device 411 includes, for example, a semiconductor laser, and irradiates the photosensitive drum 413 with laser light corresponding to an image of each color component. As a result, the exposure device 411 forms an electrostatic latent image of each color component in the image area on the surface of the photosensitive drum 413 irradiated with the laser light due to a potential difference with the background area.

[0036] The developing device 412 is a two-component developing device, and visualizes the electrostatic latent image by attaching toner of each color component to the surface of the photosensitive drum 413 to form a toner image, as will be described in detail later.

[0037] Drum cleaning device 415 has a drum cleaning blade or the like that is in sliding contact with the surface of photosensitive drum 413. Drum cleaning device 415 removes untransferred toner remaining on the surface of photosensitive drum 413 after primary transfer.

[0038] The intermediate transfer unit 42 includes an intermediate transfer belt 421, a primary transfer roller 422, a plurality of support rollers 423, a secondary transfer roller 424, a belt cleaning device 426, and the like.

[0039] The intermediate transfer belt 421 is an endless belt that is stretched in a loop around multiple support rollers 423. At least one of the multiple support rollers 423 is a drive roller, and the others are driven rollers. For example, it is preferable that roller 423A, which is disposed downstream of primary transfer roller 422 for the K component in the belt running direction, be the drive roller. This makes it easier to maintain a constant running speed of the belt in the primary transfer section. As roller 423A rotates, intermediate transfer belt 421 runs at a constant speed in the direction of arrow A.

[0040] Primary transfer rollers 422 are disposed on the inner circumferential surface side of intermediate transfer belt 421, facing photosensitive drums 413 of the respective color components. Intermediate transfer unit 42 presses primary transfer roller 422 against photosensitive drum 413 with intermediate transfer belt 421 sandwiched therebetween. As a result, intermediate transfer unit 42 forms a primary transfer nip for transferring a toner image from photosensitive drum 413 to intermediate transfer belt 421.

[0041] Secondary transfer roller 424 is disposed on the outer circumferential surface side of intermediate transfer belt 421, facing backup roller 423B disposed downstream of roller 423A in the belt running direction. In intermediate transfer unit 42, secondary transfer roller 424 is pressed against backup roller 423B with intermediate transfer belt 421 sandwiched therebetween. In this way, intermediate transfer unit 42 forms a secondary transfer nip for transferring a toner image from intermediate transfer belt 421 to paper S.

[0042] When intermediate transfer belt 421 passes through the primary transfer nip, intermediate transfer unit 42 performs primary transfer by sequentially superimposing the toner image on photosensitive drum 413 onto intermediate transfer belt 421. Specifically, intermediate transfer unit 42 applies a primary transfer bias to primary transfer roller 422, and imparts a charge of opposite polarity to the toner to the side of intermediate transfer belt 421 that contacts primary transfer roller 422. In this way, intermediate transfer unit 42 electrostatically transfers the toner image onto intermediate transfer belt 421.

[0043] Thereafter, intermediate transfer unit 42 performs a second transfer of the toner image on intermediate transfer belt 421 onto paper S as paper S passes through the secondary transfer nip. Specifically, intermediate transfer unit 42 applies a secondary transfer bias to secondary transfer roller 424, and imparts a charge of the opposite polarity to the toner to the side of paper S that contacts secondary transfer roller 424. In this way, intermediate transfer unit 42 electrostatically transfers the toner image onto paper S. Paper transport section 50 transports paper S, onto which the toner image has been transferred, towards fixing section 60.

[0044] The belt cleaning device 426 has a belt cleaning blade or the like that slides on the surface of the intermediate transfer belt 421. The belt cleaning device 426 removes the residual toner remaining on the surface of the intermediate transfer belt 421 after the secondary transfer.

[0045] The intermediate transfer unit 42 may have a configuration in which a secondary transfer belt is stretched in a loop shape around a plurality of support rollers including the secondary transfer roller, instead of the secondary transfer roller 424. This configuration is a so-called belt-type secondary transfer unit.

[0046] The fixing unit 60 fixes the toner image onto the sheet S by heating and pressurizing the sheet S, onto which the toner image has been secondarily transferred, in a fixing nip.

[0047] The paper transport section 50 includes a paper feed section 51, a paper discharge section 52, a transport path section 53, and the like. The three paper feed tray units 51a to 51c of the paper feed section 51 store paper S (standard paper, special paper) identified based on basis weight, size, etc., by pre-set type. The transport path section 53 has a plurality of transport roller pairs such as a registration roller pair 53a.

[0048] The paper transport section 50 sends out the paper sheets S stored in the paper feed tray units 51a to 51c one by one, starting from the top, and transports them to the image forming section 40 via the transport path section 53. At this time, the registration roller section, in which a registration roller pair 53a is arranged, corrects the skew of the fed paper sheets S and adjusts the transport timing. Next, the image forming section 40 performs secondary transfer of the toner image on the intermediate transfer belt 421 all at once onto one side of the paper sheets S. Next, the fixing section 60 fixes the secondary-transferred toner image onto the paper sheets. Next, the paper transport section 50 ejects the paper sheets S with the image formed thereon out of the apparatus using the paper ejection section 52, which has paper ejection rollers 52a.

[0049] The storage unit 70 includes, for example, a nonvolatile semiconductor memory, a hard disk drive, etc. The storage unit 70 stores various data such as various setting information related to the image forming apparatus 1.

[0050] The communication unit 80 includes a communication control card such as a LAN card, etc. The communication unit 80 transmits and receives various data to and from an external device (for example, a personal computer) connected to a communication network such as a LAN or WAN.

[0051] 2. Configuration of Developing Device 412 Next, the configuration of the developing device 412 will be described in detail with reference to Figures 3 and 4. Figure 3 is a schematic diagram of the vicinity of the developing device 412 as seen from the side. Figure 4 is a schematic diagram of the vicinity of the developing device 412 as seen from above. Developing device 412 is a two-component developing device, and uses a two-component developer containing toner and carrier to develop the electrostatic latent image formed on photosensitive drum 413. In this way, developing device 412 forms a toner image on photosensitive drum 413.

[0052] The developing device 412 includes a developer housing (housing) 201. The developer housing 201 contains a developer containing toner and a carrier. The developer housing 201 includes a toner transport member 202, a toner supply member 203, and a developing roller 204. The developing roller 204 functions as a toner carrier. In the examples shown in FIGS. 3 and 4, the direction parallel to the rotation axis 202a of the toner conveying member 202 is the X-axis direction, the horizontal direction perpendicular to the X-axis direction is the Y-axis direction, and the vertical direction perpendicular to both the X-axis direction and the Y-axis direction is the Z-axis direction.

[0053] Toner transport member 202 and toner supply member 203 are arranged along the axial direction of developing roller 204. Toner transport member 202 and toner supply member 203 are screw-shaped members each having a central axis and a blade formed in a spiral shape around the central axis. The developer housing 201 includes a storage chamber 206 that stores a toner transport member 202 and a storage chamber 207 that stores a toner supply member 203. The storage chambers 206 and 207 are separated by a partition wall 205 that is arranged along the XZ plane. The toner transport member 202 and the toner supply member 203 are arranged in parallel with a partition wall 205 sandwiched therebetween.

[0054] As shown in FIG. 4, the toner supply member 203 has a supply screw 203a, a reverse-winding screw 203b, and a discharge screw 203c, which are arranged coaxially in this order.

[0055] The supply screw 203 a supplies the developer to the developing roller 204 . In the following description, the direction in which the developer is transported when the supply screw 203a rotates forward is referred to as a "first transport direction H1," and the opposite direction is referred to as a "second transport direction H2." The reverse winding screw 203b is provided on the X-axis positive side of the supply screw 203a, and transports the developer in the opposite direction to the supply screw 203a. The discharge screw 203c is provided on the positive X-axis side of the reverse winding screw 203b.

[0056] The supply screw 203a transports the developer in a first transport direction H1 during its forward rotation. The reverse-winding screw 203b transports the developer in a second transport direction H2 during its forward rotation. The discharge screw 203c transports the developer in the first transport direction H1, which is the same as the supply screw 203a during its forward rotation. As a result, the developer transported by the forward rotation of the supply screw 203a is hardly transported further toward the positive direction of the X axis than the reverse-winding screw 203b. In this case, the developer transported by the forward rotation of the supply screw 203a does not proceed toward the reverse-winding screw 203b, but instead bends its path and is transported toward the toner transport member 202.

[0057] As shown in FIG. 4, the containing chamber 207 has an outlet 207a for discharging the developer at the end in the positive direction of the X axis. The discharge port 207a opens downward from the inner bottom of the containing chamber 207. The developer discharged from the discharge port 207a falls into a waste developer storage unit (not shown) and is stored therein.

[0058] The toner transport member 202 is driven to rotate in the forward direction, thereby transporting the developer in the opposite direction to the supply screw 203a.

[0059] As shown in FIG. 4, the containing chamber 206 has a supply port 206a at the end in the positive direction of the X axis for supplying the developer into the developer casing 201. A supply unit (not shown) is disposed above the supply port 206a of the developer housing 201. The supply unit includes a developer storage unit that stores replenishment developer and a transport mechanism that transports the replenishment developer from the developer storage unit. The replenishment developer is supplied to the storage chamber 206 from above through the supply port 206a. The supplied replenishment developer joins the developer circulating in the circular circulation path inside the developer housing 201 and is transported by the toner transport member 202.

[0060] As shown in FIG. 4, the partition wall 205 has openings 205a and 205b. The opening 205a transfers the developer from the toner transport member 202 to the supply screw 203a. The opening 205b transfers the developer from the supply screw 203a to the toner transport member 202. As a result, the developer circulates between the storage chamber 206 and the storage chamber 207. A portion of the developer transported by the toner supply member 203 is supplied to the developing roller 204, and the developer is magnetically attracted to the outer circumferential surface of the developing roller 204.

[0061] The image forming apparatus 1 replenishes the toner that has been consumed during image formation by replenishing the developer through the replenishing port 206a. At the same time, the image forming apparatus 1 discharges the developer through the discharge port 207a. This allows the image forming apparatus 1 to replace the deteriorated carrier in the developer housing 201 with new replenished carrier, thereby suppressing deterioration of the carrier circulating inside the developer housing 201. The rotation ratio between the toner supply member 203 and the toner transport member 202 during forward rotation, the opening width of the openings 205a and 205b, and the number of turns of the reverse winding screw 203b are set to values ​​that can maintain the amount of developer in the developer housing 201 at a predetermined amount. In this embodiment, the rotation speed of the toner supply member 203 is 466 rpm, and the rotation speed of the toner transport member 202 is 491 rpm. The rotation speed ratio between the toner supply member 203 and the toner transport member 202 is 0.95:1. In this embodiment, the opening width of the openings 205a and 205b is 32.5 mm, and the number of turns of the reverse-winding screw 203b is 7.

[0062] The developing roller 204 faces the photosensitive drum 413 at the opening of the developer housing 201. For example, the developing roller 204 transports the developer attracted to its outer circumferential surface toward a developing nip (or developing area) N, which is the portion facing the photosensitive drum 413. The developing roller 204 supplies toner to the photosensitive drum 413 at the developing nip N.

[0063] The developing device 412 includes a prevention member 208 provided above the developing roller 204 . The prevention member 208 suppresses the dust (scattered toner) caused by the developer that is generated when the developing roller 204 rotates.

[0064] The developing device 412 includes a suction unit 209 that sucks the scattered toner generated between the photosensitive drum 413 and the developing roller 204 . The suction unit 209 has a duct 209a arranged along the outer surface of the upper side of the developer housing 201, and a fan (not shown). A suction port 209b at the tip of the duct 209a is installed in a position close to the developing roller 204 on the surface of the photosensitive drum 413. The fan provided in the suction unit 209 sucks air inside the duct 209a. As a result, scattered toner generated between the photosensitive drum 413 and the developing roller 204 is taken into the duct 209a through the suction port 209b. After being transported through the duct 209a, the scattered toner is collected in a collection tank (not shown). The control unit 100 controls the start and stop of rotation of the fan provided in the suction unit 209, changes in the rotation speed, and the like.

[0065] In the suction unit 209, toner accumulates on the wall surface of the duct 209a, and the accumulated toner spills onto the photosensitive drum 413 or paper, causing contamination inside the image forming apparatus 1 or image defects that smear the image. In particular, near suction port 209b, the laminar flow generated by the rotation of developing roller 204 and the laminar flow generated by the rotation of photosensitive drum 413 intersect, generating a vortex airflow. Therefore, even if the suction air speed at suction unit 209 is increased, the toner cannot be completely sucked and collected near suction port 209b, and the toner tends to accumulate. The vicinity of suction port 209b is, for example, the tip portion of prevention member 208 (the end portion on the photosensitive drum 413 side).

[0066] In this embodiment, the image forming apparatus 1 applies vibration to the preventing member 208 to crush the toner accumulated on the preventing member 208. Next, the image forming apparatus 1 collects the crushed toner by sucking it with the suction unit 209, or causes it to adhere to the developing roller 204, thereby reducing the amount of toner accumulated on the preventing member 208. In this way, the image forming apparatus 1 prevents image defects caused by the accumulated toner spilling onto the photosensitive drum 413 or paper.

[0067] As shown in FIGS. 3 and 5, the image forming unit 41 includes a pressure separation mechanism 416. The pressure separation mechanism 416 presses the developing device 412 against the photosensitive drum 413 or separates the developing device 412 from the photosensitive drum 413. Fig. 3 is a diagram showing an example of a state in which the developing device 412 is pressed against the photosensitive drum 413. Fig. 5 is a diagram showing an example of a state in which the developing device 412 is separated from the photosensitive drum 413. The pressure-removal mechanism 416 is, for example, an air cylinder. The pressure-removal mechanism 416 includes a movable part 416a that is movable in the left-right direction in the drawing. The control unit 100 controls the pressure-removal mechanism 416 to press the developing device 412 against the photosensitive drum 413 or to separate the developing device 412 from the photosensitive drum 413. The tip of the movable part 416a is fixed to the developer housing 201. Therefore, the developing device 412 moves in conjunction with the movement of the movable part 416a. Specifically, when movable portion 416a moves in a direction away from photosensitive drum 413 (to the right in the figure), developing device 412 also moves in the same direction, thereby allowing developing device 412 to be separated from photosensitive drum 413 (see FIG. 5). On the other hand, when movable portion 416a moves in a direction approaching photosensitive drum 413 (to the left in the figure), developing device 412 also moves in the same direction. This allows developing device 412 to be pressed against (pressed into) photosensitive drum 413 (see FIG. 3).

[0068] When the control unit 100 vibrates the developer casing 201 of the developing device 412 using the vibration mechanism (drive transmission member 214), the control unit 100 first separates the developing device 412 from the photosensitive drum 413 using the pressure separation mechanism 416 (see FIG. 5). Then, the control unit 100 vibrates the developer casing 201 of the developing device 412 using the vibration mechanism (drive transmission member 214). This increases the amplitude of vibration of the developer casing 201, thereby increasing the efficiency with which the vibration mechanism vibrates the developer casing 201. During image formation, control unit 100 presses developing device 412 against photosensitive drum 413 using pressure separation mechanism 416 (see FIG. 3). This positions developing device 412 relative to photosensitive drum 413, and allows development nip N to be formed between photosensitive drum 413 and development roller 204.

[0069] 3. Configuration of the driving mechanism 210 FIG. 6 is a schematic diagram showing an example of the configuration of the drive mechanism 210 provided in the developing device 412. As shown in FIG. The drive mechanism 210 rotates the toner transport member 202 about a rotation shaft 202a of the toner transport member 202 to transport the developer stored in the storage chamber 206. An end 202b of the rotation shaft 202a on the positive side of the X axis is rotatably supported by a bearing 211 provided in the developer housing 201. The driving mechanism 210 applies vibration to the preventing member 208 to break up the toner accumulated on the preventing member 208 .

[0070] 6, the toner transport member 202 includes a screw member 202c disposed inside the developer housing 201 and an engaging member 202d disposed outside the developer housing 201. The screw member 202c and the engaging member 202d are integrally formed. The engaging member 202d is disposed at the end 202b of the rotary shaft 202a so as to abut against the outer wall surface 201a of the developer housing 201. The engaging member 202d has an engaging portion 202e that protrudes in the positive direction of the X-axis at a predetermined angle relative to the X-axis direction.

[0071] The drive mechanism 210 includes a drive motor 212 , an elastic member 213 , and a drive transmission member 214 . As shown in FIG. 8, the drive transmission member 214 is a substantially cylindrical member. Fig. 7 is a schematic diagram showing the positional relationship between drive transmission member 214 and end 202f of engagement portion 202e as viewed from the negative direction of the X axis in the state of Fig. 6. The shaded portion of drive transmission member 214 shown in Fig. 6 is a cross-sectional view taken along line VII-VII in Fig. 7.

[0072] Under the control of the control unit 100, the drive motor 212 rotates the drive transmission member 214 around a rotation axis parallel to the X-axis direction, switching between a first direction and a second direction. The first direction is a forward rotation direction, which is counterclockwise when viewed from the negative X-axis direction. The second direction is a reverse rotation direction, which is clockwise when viewed from the negative X-axis direction, which is the opposite direction to the first direction. The elastic member 213 is a spring or the like provided along the X-axis direction between the inner wall surface 215 of the housing of the image forming apparatus 1 and the drive transmission member 214. The elastic member 213 is expandable and contractible in the X-axis direction.

[0073] The drive transmission member 214 has an engaged portion 214a that engages with the engaging portion 202e of the engaging member 202d on an opposing surface 214d that faces the engaging member 202d. The engaged portion 214a has a substantially right-angled trapezoidal shape in the XY plane, and includes a parallel portion 214b that is parallel to the X axis, and an inclined portion 214c that is inclined at a predetermined angle relative to the X axis. The angle at which the inclined portion 214c is inclined relative to the X axis is substantially the same as the angle at which the engaging portion 202e of the engaging member 202d is inclined relative to the X axis, and the inclined portion 214c and the engaging portion 202e are parallel to each other. 8, the drive transmission member 214 has a through-hole 214e at the center in the YZ plane. The through-hole 214e passes through the drive transmission member 214 in the X-axis direction. A rotation shaft 214f ​​(see FIG. 22) of the drive transmission member 214 is inserted into the through-hole 214e.

[0074] <4. Rotation in the first direction> Next, the operation of the drive mechanism 210 and the toner conveying member 202 when the drive transmission member 214 rotates in the first direction will be described. 6, the drive transmission member 214 is biased toward the engaging member 202d by the elastic force F1 of the elastic member 213. The engaging portion 202e of the engaging member 202d and the engaged portion 214a of the drive transmission member 214 are in an engaged state. The end 202f of the engaging portion 202e abuts against the parallel portion 214b of the engaged portion 214a. Opposing surface of the drive transmission member 214 214d is in contact with an opposing surface 202g, which is the surface of the engaging member 202d that faces the drive transmission member 214. In this state, the control unit 100 drives the drive motor 212 so as to rotate the drive transmission member 214 in the first direction. The rotational drive force of the drive motor 212 is transmitted to the rotation shaft 202a of the toner conveying member 202 via the engaged portion 214a of the drive transmission member 214 and the engaging portion 202e of the engaging member 202d, which are in the engaged state. At this time, the developer transport force exerted by the rotation of toner transport member 202 in the first direction is greater than the load that toner transport member 202 receives from the developer contained in storage chamber 206. Therefore, toner transport member 202 rotates in the first direction about rotation shaft 202a. As a result, the developer contained in storage chamber 206 is transported from the negative X-axis direction to the positive X-axis direction. In the rotational operation in the first direction, the drive transmission member 214 and the toner transport member 202 rotate in the first direction while the engaged portion 214a and the engaging portion 202e remain engaged with each other.

[0075] As described above, in the rotational movement in the first direction, the drive transmission member 214 performs a first movement of transmitting a drive force to the toner transport member 202 for transporting toner. The control unit 100 rotates the drive transmission member 214 in the first direction while the engaged portion 214a of the drive transmission member 214 is engaged with the engaging portion 202e of the toner transport member 202. As a result, the control unit 100 causes the drive transmission member 214 to transmit, as a first operation, a driving force greater than the rotational load of the toner transport member 202 to the toner transport member 202, thereby rotating the toner transport member 202 in the first direction and transporting the toner. The drive transmission member 214 transmits the drive force of the drive motor 212 to the toner conveying member 202 via the engaged portion 214a of the drive transmission member 214 and the engaging portion 202e of the engaging member 202d, which are in an engaged state in the first operation.

[0076] <5. Rotation in the second direction> Next, the operation of the drive mechanism 210 and the toner conveying member 202 when the drive transmission member 214 rotates in the second direction will be described. 9 to 20 are schematic diagrams showing configuration examples of the drive mechanism 210 when the drive transmission member 214 rotates in the second direction.

[0077] The control unit 100 drives the drive motor 212 so that the drive transmission member 214 rotates in the second direction while the engaging portion 202e of the engaging member 202d and the engaged portion 214a of the drive transmission member 214 are engaged with each other. When the drive transmission member 214 rotates in the second direction, the engaging portion 202e comes into contact with the inclined portion 214c of the engaged portion 214a, as shown in Fig. 9. The hatched portion of the drive transmission member 214 shown in Fig. 9 is a cross-sectional view taken along line XX in Fig. 10.

[0078] 11 shows a state in which the control unit 100 has further rotated the drive transmission member 214 in the second direction from the state shown in Fig. 9. In this embodiment, when the drive transmission member 214 rotates in the second direction, the load that the toner transport member 202 receives from the developer stored in the storage chamber 206 is greater than the transport force that transports the developer when the toner transport member 202 rotates in the second direction. Therefore, the toner transport member 202 does not rotate and remains stationary. At this time, the engaged portion 214a receives a force F2 from the engaging portion 202e at the inclined portion 214c as shown in Fig. 11. The hatched portion of the drive transmission member 214 shown in Fig. 11 is a cross-sectional view taken along line XII-XII shown in Fig. 12. When engaged portion 214a receives force F2, drive transmission member 214 moves in the positive direction of the X axis, and opposing surface 214d of drive transmission member 214 and opposing surface 202g of engaging member 202d move away from each other. As a result, elastic member 213 contracts in the X axis direction.

[0079] Fig. 13 shows a state in which control unit 100 has further rotated drive transmission member 214 in the second direction from the state shown in Fig. 11. As shown in Fig. 13, drive transmission member 214 moves further in the positive direction of the X axis. The shaded portion of drive transmission member 214 shown in Fig. 13 is a cross-sectional view taken along line XIV-XIV in Fig. 14. As the drive transmission member 214 moves further in the positive direction of the X axis, the engagement between the engaging portion 202e of the engaging member 202d and the engaged portion 214a of the drive transmission member 214 is released, and the end portion 202f of the engaging portion 202e abuts against the opposing surface 214d of the drive transmission member 214. The elastic member 213 further contracts in the X axis direction. The elastic member 213 shown in Figure 13 is in its most contracted state.

[0080] Fig. 15 shows a state in which control unit 100 has further rotated drive transmission member 214 in the second direction from the state shown in Fig. 13. As shown in Fig. 15, end 202f of engagement portion 202e abuts against opposing surface 214d of drive transmission member 214, and drive transmission member 214 rotates in the second direction while elastic member 213 remains in its most contracted state. The hatched portion of drive transmission member 214 shown in Fig. 15 is a cross-sectional view taken along line XVI-XVI in Fig. 16.

[0081] Fig. 17 shows a state in which control unit 100 has further rotated drive transmission member 214 in the second direction from the state shown in Fig. 15. As shown in Fig. 17, end 202f of engaging portion 202e reaches the position of parallel portion 214b of engaged portion 214a, and end 202f abuts against parallel portion 214b. The shaded portion of drive transmission member 214 shown in Fig. 17 is a cross-sectional view taken along line XVIII-XVIII in Fig. 18. When end 202f abuts against parallel portion 214b, contraction of elastic member 213 is released, and elastic repulsive force F3 of elastic member 213 moves drive transmission member 214 in the negative X-axis direction.

[0082] Fig. 19 shows a state in which the control unit 100 has further rotated the drive transmission member 214 in the second direction from the state shown in Fig. 17. As shown in Fig. 19, the engaging portion 202e of the engaging member 202d and the engaged portion 214a of the drive transmission member 214 are in an engaged state. The hatched portion of the drive transmission member 214 shown in Fig. 19 is a cross-sectional view taken along the line XX-XX shown in Fig. 20. The drive transmission member 214 moves further toward the negative X-axis direction due to the elastic repulsive force F3 of the elastic member 213. The opposing surface 214d of the drive transmission member 214 collides with the opposing surface 202g of the engaging member 202d. In other words, the elastic repulsive force F3 that had been accumulated in the elastic member 213 is released in a short period of time, causing the drive transmission member 214 to collide with the engaging member 202d. As a result, the drive transmission member 214 applies an impact force F4 to the screw member 202c of the toner transport member 202. The vibration caused by the impact force F4 received by the screw member 202c is transmitted to the prevention member 208 via the bearing 211 and the developer casing 201. When the preventing member 208 vibrates, the toner accumulated on the preventing member 208 is crushed, and the crushed toner is sucked and collected by the suction unit 209. Alternatively, the crushed toner adheres to the developing roller 204. As described above, the drive transmission member 214 functions as a vibration mechanism of the present invention that applies vibration to the developer housing 201 of the developing device 412 .

[0083] When the control unit 100 further rotates the drive transmission member 214 in the second direction from the state shown in Fig. 19, the state returns to the state shown in Fig. 9. In the states shown in Figs. 9 to 20, the rotation of the toner transport member 202 remains stopped. The control unit 100 continues to rotate the drive transmission member 214 in the second direction, causing the drive transmission member 214 to repeatedly collide with the engagement member 202d.

[0084] As described above, in the rotational movement in the second direction, the drive transmission member 214 performs the second movement, which is a movement to vibrate the prevention member 208 provided in the developing device 412 and which prevents the toner from scattering. The control unit 100 rotates the drive transmission member 214 in the second direction, and causes the drive transmission member 214 to perform the second operation while the rotation of the toner transport member 202 is stopped. The drive transmission member 214 is displaceable along the axial direction (X-axis direction) of the toner transport member 202. The drive transmission member 214 performs a second operation when displacing from a position where the engagement between the engaged portion 214a and the engaging portion 202e is released to a position where the engagement between the engaged portion 214a and the engaging portion 202e is engaged.

[0085] In the above-mentioned rotational movement in the first direction and the rotational movement in the second direction, the drive transmission member 214 switches between the first movement and the second movement. The control unit 100 switches the rotation direction of the drive transmission member 214, thereby causing the drive transmission member 214 to switch between the first operation and the second operation. The control unit 100 functions as a first control unit of the present invention that controls the vibration mechanism (drive transmission member 214).

[0086] <6. Effect of the second action> FIG. 21 shows the effect of suppressing image defects by the second operation. The example shown in FIG. 21 is a result of a durability test performed on the image forming apparatus 1. The horizontal axis of Figure 21 represents the number of A4-sized sheets printed by the image forming apparatus 1. The vertical axis represents the toner spill rate, which is the ratio of the number of sheets on which image stains due to toner spill occurred to the total number of sheets printed. The solid line represents the toner spill rate when the second operation is not performed. The dashed line represents the toner spill rate when the second operation is performed. During the durability evaluation, the temperature inside the image forming apparatus 1 was 23°C and the humidity was 50%. The coverage of each color during the durability evaluation was 5%. During the durability evaluation, the image forming apparatus 1 continuously printed on A4-sized paper. During the durability evaluation, the number of images stained by toner spills was counted every 2,000 sheets printed, and the toner spill rate was calculated. The target value for the toner spill rate during the durability evaluation was 0.5% or less, and the durability evaluation period was for printing 350,000 sheets (developer lifespan). As shown in Figure 21, when the second operation was not performed (without the second operation), the rate of toner spillage gradually increased as continuous printing was performed, and after printing 50,000 sheets, the rate of toner spillage was 1.2%, which was not the target. On the other hand, when the second operation of the present invention was performed every 3,000 sheets printed (when the second operation was performed), the toner spill rate remained below the target value of 0.5% during the 350,000 sheets printed period, verifying that the target could be achieved.

[0087] <7.Other> Developing device 412 may include a sealing member such as urethane foam or a soft sealing material to prevent leakage of toner stored in developer housing 201. The sealing member is a soft member that can fill gaps in developer housing 201. When toner transport member 202 is connected to preventing member 208 via the sealing member, vibrations caused by impact force F4 received by toner transport member 202 are suppressed by the elasticity of the sealing member. For this reason, it is preferable that toner conveying member 202 is connected to preventing member 208 via a rigid body. In this case, vibrations caused by impact force F4 received by toner conveying member 202 are less likely to be suppressed and are efficiently transmitted to preventing member 208. This makes it possible to efficiently crush toner accumulated on preventing member 208. The rigid body includes multiple rigid bodies fastened together with a fastening member, or multiple rigid bodies bonded together with a curable adhesive or the like.

[0088] In the second operation, when the drive transmission member 214 applies impact force F4 to the toner conveying member 202, the impact generates a sound. The sound allows the user to recognize that the second operation is being performed. However, if the surroundings of the image forming apparatus 1 are quiet, the sound may be bothersome to the user. Therefore, in this embodiment, the drive transmission member 214 performs the second operation at the same timing as the charge cleaning operation performed by the image forming apparatus 1. The charge cleaning operation is an operation in which a charge cleaning member that cleans the charge wire of the charging device 414 moves back and forth in a direction along the charge wire. In the image forming apparatus 1, the control unit 100 performs the charge cleaning operation every time 3,000 sheets of A4 size paper are printed. The control unit 100 performs the charge cleaning operation after each print job is completed. As a result, the sound generated in the second operation and the sound generated in the charging cleaning operation occur simultaneously, so that the sound generated in the second operation of this embodiment is not conspicuous. That is, the second operation of this embodiment is performed simultaneously with an operation different from the second operation performed by the image forming apparatus 1.

[0089] The drive transmission member 214 may perform the second operation during operation of a fan provided in the image forming apparatus 1. The fan is a fan that prevents a temperature rise inside the image forming apparatus 1, and an ozone fan that performs a purification process by absorbing ozone generated inside the image forming apparatus 1 into a filter. As a result, the sound generated in the second operation and the sound generated by the operation of the fan are generated simultaneously, so that the sound generated in the second operation alone is not noticeable.

[0090] The drive transmission member 214 may perform the second operation during operation of a post-processing device connected to the image forming apparatus 1. The post-processing device is a device that performs post-processing such as stapling, punching, sorting, saddle-stitching, and tri-folding on paper after image formation. As a result, the sound generated during the second operation and the sound generated by the operation of the post-processing device are generated simultaneously, so that the sound generated during the second operation alone is not noticeable.

[0091] <8. Effects> As described above, the image forming apparatus 1 according to this embodiment includes the developing device 412 that develops a latent image by adhering toner to the latent image via a toner carrier (developing roller 204) disposed opposite the latent image carrier (photosensitive drum 413) on which the latent image is formed. The image forming apparatus 1 also includes a pressing mechanism 416 that presses the developing device 412 against the latent image carrier or separates the developing device 412 from the latent image carrier. The image forming apparatus 1 also includes a vibration mechanism that applies vibration to the housing (developer housing 201) of the developing device 412. The image forming apparatus 1 also includes a first control unit (control unit 100) that controls the pressing mechanism 416 and the vibration mechanism. After separating the developing device 412 from the latent image carrier using the pressing mechanism 416, the first control unit vibrates the housing of the developing device 412 using the vibration mechanism. This increases the amplitude of vibration of the developer housing 201, thereby increasing the efficiency of the vibration mechanism in vibrating the developer housing 201. As a result, toner accumulated in the developing device 412 can be efficiently removed, and image defects caused by toner can be more reliably suppressed.

[0092] In the image forming apparatus 1 according to this embodiment, the developing device 412 includes a drive transmission member 214 that transmits a drive force to the toner transport member 202 that transports the toner. The vibration mechanism is the drive transmission member 214. The drive transmission member 214 switches between a first operation that transmits a drive force for transporting the toner to the toner transport member 202, and a second operation that vibrates a prevention member 208 provided in the developing device 412 that prevents the toner from scattering. As a result, the preventing member 208 can be vibrated by the drive transmission member 214, which is a member that transmits the drive force for transporting the toner to the toner transport member 202. In other words, there is no need for a dedicated part for vibrating the preventing member 208. Therefore, it is possible to suppress image defects caused by toner accumulated in the developing device 412 while suppressing an increase in the size or cost of the device.

[0093] In the image forming apparatus 1 according to this embodiment, the first control section (control section 100) switches the rotation direction of the drive transmission member 214, thereby causing the drive transmission member 214 to switch between the first operation and the second operation. This allows the drive transmission member 214 to easily switch between the first operation and the second operation by switching the rotation direction of the drive transmission member 214.

[0094] In image forming apparatus 1 according to this embodiment, first control unit (control unit 100) rotates drive transmission member 214 in a first direction in a state in which engaged portion 214a of drive transmission member 214 is engaged with engaging portion 202e of toner transport member 202. As a result, the first control unit causes drive transmission member 214 to transmit a driving force greater than the rotational load of toner transport member 202 to toner transport member 202 as a first operation, thereby rotating toner transport member 202 in the first direction to transport toner. The first control unit rotates the drive transmission member 214 in a second direction that is opposite to the first direction, and causes the drive transmission member 214 to perform a second operation while the rotation of the toner transport member 202 is stopped. This allows the drive transmission member 214 to easily switch between the first operation and the second operation by simply switching the rotation direction of the drive transmission member 214.

[0095] The image forming apparatus 1 according to this embodiment is provided with a regulating member (one-way clutch 220, or solenoid 232 and protrusion member 233) that regulates the toner conveying member 202 so that it does not rotate in the second direction when the drive transmission member 214 rotates in the second direction. This makes it possible to prevent image defects such as uneven screw pitch from occurring.

[0096] In the image forming apparatus 1 according to this embodiment, the drive transmission member 214 transmits the drive force to the toner conveying member 202 via the engaged portion 214a of the drive transmission member 214, which is in an engaged state in the first operation, and the engaging portion 202e of the toner conveying member 202. This allows the driving force for conveying the toner to the toner conveying member 202 to be transmitted with a simple configuration.

[0097] In the image forming apparatus 1 according to this embodiment, the drive transmission member 214 is displaceable along the axial direction of the toner transport member 202. The drive transmission member 214 performs a second operation when displacing from a position where the engagement between the engaged portion 214a and the engaging portion 202e is released to a position where the engagement between the engaged portion 214a and the engaging portion 202e is engaged. This allows the prevention member 208 to vibrate with a simple configuration.

[0098] In the image forming apparatus 1 according to this embodiment, the developing device 412 includes an elastic member 213. The drive transmission member 214 utilizes the elastic force of the elastic member 213 to perform the second operation. This allows the prevention member 208 to vibrate with a simple configuration.

[0099] Image forming apparatus 1 according to this embodiment includes detection unit 231 that detects the rotational load of toner conveying member 202. Image forming apparatus 1 includes a second control unit (control unit 100) that does not restrict the rotation of toner conveying member 202 when the rotational load detected by detection unit 231 is greater than a predetermined value, and restricts the rotation of toner conveying member 202 when the rotational load is equal to or less than the predetermined value. This makes it possible to prevent image defects such as uneven screw pitch from occurring.

[0100] In the image forming apparatus 1 according to this embodiment, the toner transport member 202 is connected to the prevention member 208 via a rigid body. As a result, vibrations caused by the impact force F4 received by the toner transport member 202 are not easily suppressed and are efficiently transmitted to the preventing member 208. As a result, the toner accumulated on the preventing member 208 can be efficiently crushed.

[0101] In the image forming apparatus 1 according to this embodiment, the second operation is performed simultaneously with an operation different from the second operation performed in the image forming apparatus 1. This prevents the sound generated during the second operation from being noticeable when the surroundings of the image forming apparatus 1 are quiet.

[0102] The above has been a specific explanation based on an embodiment of the present invention, but the detailed configuration and detailed operation of each device that makes up the image forming apparatus 1 can also be modified as appropriate within the scope that does not deviate from the spirit of the present invention.

[0103] [Variation 1] Next, the image forming apparatus 1 according to the first modification will be described. In the following description, the same components as those in the image forming apparatus 1 according to the embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0104] In the above embodiment, when the drive transmission member 214 rotates in the second direction, the load that the toner transport member 202 receives from the developer is greater than the transport force that transports the developer due to the rotation of the toner transport member 202 in the second direction. Therefore, the toner transport member 202 does not rotate and remains stationary. In Modification 1, when the drive transmission member 214 rotates in the second direction, the load that the toner transport member 202 receives from the developer is equal to or less than the transport force that transports the developer when the toner transport member 202 rotates in the second direction. In this case, the toner transport member 202 rotates in the second direction, and the developer in the developer housing 201 is transported in the direction opposite to the direction shown in FIG. 4. At this time, the developer in the developer housing 201 is discharged in excess from the discharge port 207a. As a result, the amount of developer in the developer housing 201 becomes less than the predetermined amount, and the amount of developer supplied to the developing roller 204 becomes insufficient, resulting in image defects such as screw pitch unevenness. Screw pitch unevenness is density unevenness that occurs in the formed image.

[0105] In order to prevent the above-mentioned image defects, developing device 412 of modified example 1 is provided with a one-way clutch 220 shown in Figure 22. Figure 22 is a schematic view of the vicinity of developing device 412 of modified example 1 as seen from above. The one-way clutch 220 is provided on the rotation shaft 202a of the toner transport member 202 outside the developer casing 201 on the positive X-axis side, which is the opposite side to the side on which the drive transmission member 214 is disposed. When the drive transmission member 214 rotates in the first direction in the first operation, the one-way clutch 220 does not restrict the toner transport member 202 from rotating in the first direction. On the other hand, when the drive transmission member 214 rotates in the second direction in the second operation, the one-way clutch 220 restricts the toner transport member 202 from rotating in the second direction. The one-way clutch 220 functions as a restricting member.

[0106] [Modification of Modification 1] Next, the image forming apparatus 1 according to the modified example 1 will be described. In the following description, the same components as those in the image forming apparatus 1 according to the embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0107] Image forming apparatus 1 of this modified example includes, instead of one-way clutch 220, a detection unit 231 shown in Fig. 23, a solenoid 232, and a protrusion member 233 shown in Fig. 24. Fig. 23 is a block diagram showing a control function for the rotation restriction operation of toner conveying member 202 of this modified example. Fig. 24 is a schematic view of the vicinity of developing device 412 of this modified example seen from above. FIG. 25 is a schematic perspective view showing the vicinity of the solenoid 232 and the protruding member 233.

[0108] The detection unit 231 detects the load applied to the drive motor 212, and thereby detects the rotational load of the toner transport member 202 via the drive transmission member 214. The rotational load of the toner transport member 202 is the load that the toner transport member 202 receives from the developer stored in the storage chamber 206. The detection unit 231 outputs the detected rotation load of the toner conveying member 202 to the control unit 100.

[0109] The solenoid 232 and the protruding member 233 are provided outside the developer casing 201 on the positive X-axis side, which is the opposite side to the side on which the drive transmission member 214 is disposed. The protruding member 233 is a plate-shaped member provided on the rotation shaft 202 a of the toner transport member 202 .

[0110] The solenoid 232 includes a movable part 232a that is displaceable in the Y-axis direction. Under the control of the control unit 100, the solenoid 232 displaces the movable part 232a so that the tip 232b of the movable part 232a is located at the first position B1 or the second position B2. 25, when tip 232b of movable part 232a is located at first position B1, tip 232b does not interfere with protruding member 233 even when toner conveying member 202 rotates. Therefore, toner conveying member 202 is rotatable. In other words, the rotation of toner conveying member 202 is not restricted. On the other hand, when tip 232b of movable part 232a is located at second position B2, even if toner conveying member 202 tries to rotate, tip 232b interferes with protruding member 233. Therefore, toner conveying member 202 cannot rotate. In other words, the rotation of toner conveying member 202 is restricted.

[0111] In this modification, the control unit 100 executes a rotation control process shown in FIG.

[0112] (Rotation control processing) The control unit 100 acquires the rotation load of the toner conveying member 202 detected by the detection unit 231 during the rotation operation in the first direction (step S1). Next, the control unit 100 determines whether the rotation load of the toner conveying member 202 acquired in step S1 is greater than a predetermined value. The predetermined value is set in advance, and is, for example, 500 gf·cm.

[0113] The case where the rotational load of toner transport member 202 is greater than the predetermined value (step S2; YES) will be described. In this case, when drive transmission member 214 rotates in the second direction, the load that toner transport member 202 receives from the developer is greater than the transport force that transports the developer when toner transport member 202 rotates in the second direction. In other words, this is the case where toner transport member 202 does not rotate and remains stationary during rotation in the second direction. In this case, the control unit 100 controls the solenoid 232 so that the tip 232b of the movable part 232a is positioned at the first position B1 during the rotational movement in the first direction and the rotational movement in the second direction (step S3), and ends the rotation control process.

[0114] On the other hand, a case where the rotation load of the toner transport member 202 is equal to or less than a predetermined value (step S2; NO) will be described. In this case, when the drive transmission member 214 rotates in the second direction, the load that the toner transport member 202 receives from the developer is equal to or less than the transport force that transports the developer when the toner transport member 202 rotates in the second direction. In this case, the control unit 100 controls the solenoid 232 so that the tip 232b of the movable part 232a is located at the first position B1 during the rotation in the first direction, and also controls the solenoid 232 so that the tip 232b of the movable part 232a is located at the second position B2 during the rotation in the second direction (step S4), and then ends the rotation control process.

[0115] That is, in the rotation control process, when the rotation load of toner conveying member 202 detected by detection unit 231 is greater than a predetermined value, control unit 100 does not restrict the rotation of toner conveying member 202. When the rotation load of toner conveying member 202 detected by detection unit 231 is equal to or less than a predetermined value, control unit 100 restricts the rotation of toner conveying member 202. Control unit 100 functions as a second control unit. Solenoid 232 and protrusion member 233 function as restricting members.

[0116] [Other variations] For example, in the above embodiment, the developing device 412 is of a two-component developing type, but the developing device 412 may be of a single-component developing type.

[0117] In addition, in the above embodiment, the drive transmission member 214 is described as an example of the vibration mechanism of the present invention, but the present invention is not limited to this. For example, a vibration mechanism that directly applies vibration to the housing of the developing device may be provided.

[0118] In the above description, examples have been disclosed in which a hard disk drive (HDD) or a semiconductor nonvolatile memory is used as a computer-readable medium for the program according to the present invention, but the present invention is not limited to these examples. Portable recording media such as CD-ROMs can also be used as other computer-readable media. Furthermore, carrier waves can also be used as a medium for providing data for the program according to the present invention via a communication line. [Explanation of symbols]

[0119] 1. Image forming device 100 control unit (first control unit, second control unit) 10 Image reading unit 11 Automatic document feeder 12 Original image scanning device 12a CCD sensor 20 Operation display section 21 Display section 22 Control section 30 Image processing section 40 Image forming unit 41, 41C, 41K, 41M, 41Y Image forming units 411 Exposure equipment 412 Developing device 413 Photosensitive drum (latent image carrier) 414 Charging device 415 Drum cleaning device 416 Pressure release mechanism 416a Moving parts 42 Intermediate transfer unit 421 Intermediate transfer belt 422 Primary transfer roller 423 Support Roller 423A Roller 423B Backup Roller 424 Secondary transfer roller 426 Belt cleaning device 50 Paper transport section 51 Paper feed section 51a, 51b, 51c Paper feed tray unit 52 Paper output section 52a Paper ejection roller 53 Conveying path section Registration roller pair 60 Fixing unit 70 Storage section 80 Communications Department 201 Developer housing (housing) 201a exterior wall 202 Toner transport member 202a Rotation axis 202b End 202c Screw element 202d Engagement member 202e Engagement part 202f end 202g opposing surface 203 Toner supply member 203a Supply screw 203b Reverse winding screw 203c Discharge screw 204 Developing roller (toner carrier) 205 Bulkhead 205a,205b opening Containment Room 206 206a Supply port Containment Room 207 207a Outlet 208 Prevention member 209 Suction part 209a Duct 209b Suction port 210 Drive mechanism 211 Bearings 212 Drive motor 213 Elastic Members 214 Drive transmission member (vibration mechanism) 214a Engaged part 214b Parallel part 214c Slope 214d Opposite surface 214e Through hole 214f Rotation axis 215 Inner wall surface 220 One-way clutch (regulating member) 231 Detection unit 232 Solenoid (regulating member) 233 Protruding member (regulating member) N Development nip S paper

Claims

1. a developing device that develops a latent image by attaching toner to the latent image via a toner carrier disposed opposite a latent image carrier on which the latent image is formed; a pressing / separating mechanism that presses the developing device against the latent image carrier or separates the developing device from the latent image carrier; a vibration mechanism that applies vibration to a housing of the developing device; a first control unit that controls the pressing mechanism and the vibration mechanism; Equipped with The image forming apparatus, wherein the first control unit causes the vibration mechanism to vibrate a housing of the developing device after the developing device is separated from the latent image carrier by the pressure separation mechanism.

2. the developing device includes a drive transmission member that transmits a drive force to a toner transport member that transports the toner; the vibration mechanism is the drive transmission member, 2. The image forming apparatus according to claim 1, wherein the drive transmission member switches between a first operation of transmitting the drive force for transporting the toner to the toner transport member and a second operation of vibrating a prevention member provided in the developing device that prevents the toner from scattering.

3. The image forming apparatus according to claim 2 , wherein the first control section switches the rotation direction of the drive transmission member to switch between the first operation and the second operation.

4. The first control unit by rotating the drive transmission member in a first direction in a state in which an engaged portion of the drive transmission member and an engaging portion of the toner transport member are engaged with each other, the drive transmission member transmits a drive force greater than a rotational load of the toner transport member to the toner transport member as the first operation, and the toner transport member is rotated in the first direction to transport the toner; 4. The image forming apparatus according to claim 3, wherein the drive transmission member is rotated in a second direction opposite to the first direction, and the drive transmission member is caused to perform the second operation while the rotation of the toner transport member is stopped.

5. The image forming apparatus according to claim 4 , further comprising a regulating member that regulates the toner transport member so that it does not rotate in the second direction when the drive transmission member rotates in the second direction.

6. 3. The image forming apparatus according to claim 2, wherein the drive transmission member transmits the driving force to the toner transport member via an engaged portion of the drive transmission member that is in an engaged state during the first operation and an engaging portion of the toner transport member.

7. 7. The image forming apparatus of claim 6, wherein the drive transmission member is displaceable along the axial direction of the toner transport member, and performs the second operation when displaced from a position in which the engaged portion and the engaging portion are disengaged to a position in which the engaged portion and the engaging portion are engaged.

8. the developing device includes an elastic member, The image forming apparatus according to claim 2 , wherein the drive transmission member performs the second movement by utilizing the elastic force of the elastic member.

9. a detection unit that detects a rotation load of the toner transport member; a second control unit that does not restrict rotation of the toner transport member when the rotation load detected by the detection unit is greater than a predetermined value, and restricts rotation of the toner transport member when the rotation load is equal to or less than the predetermined value; The image forming apparatus according to claim 2 , comprising:

10. 3. The image forming apparatus according to claim 2, wherein the toner transport member is connected to the prevention member via a rigid body.

11. The image forming apparatus according to claim 2 , wherein the second operation is performed simultaneously with an operation different from the second operation performed by the image forming apparatus.

Images