Developing device, processing cartridge, and image forming apparatus
By employing a positioning mechanism that engages with the toner concentration detection sensor in the developing unit, the problem of sensor position deviation is solved, achieving high-precision toner concentration detection and stable replenishment control.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- RICOH CO LTD
- Filing Date
- 2023-03-20
- Publication Date
- 2026-06-23
Smart Images
Figure CN116909112B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a developing apparatus for developing a latent image formed on the surface of an image carrier, and a processing cartridge and an image forming apparatus including the developing apparatus. Background Technology
[0002] In the developing apparatus of an image forming apparatus using an electrophotographic method, such as a copier, printer, fax machine, or their multifunctional peripheral device, a developing apparatus using a toner concentration detection sensor, such as a magnetic sensor, is known (see, for example, Patent Document 1) in order to detect the toner concentration (the proportion of toner in a developer composed of toner and carrier) of a two-component developer contained in the developing apparatus.
[0003] In addition, in such developing apparatuses, it is known that the toner concentration detection sensor is held in the developing chamber.
[0004] In the past, during the manufacturing or maintenance of developing equipment, whenever a toner concentration detection sensor was installed in the developing chamber, the position of the toner concentration detection sensor relative to the developing chamber would deviate from the desired position.
[0005] Therefore, variations will occur in the toner concentration detected by the toner concentration detection sensor and in the toner replenishment control based on the detection result.
[0006] The present invention was proposed to solve the above-mentioned problems, and its purpose is to provide a developing apparatus, a processing cartridge, and an image forming apparatus that can accurately determine the position of the toner concentration detection sensor relative to the developing cartridge at a desired position.
[0007] [Patent Document 1] Japanese Patent Application Publication No. 2008-276118 Summary of the Invention
[0008] The present invention relates to a developing apparatus for developing a latent image formed on the surface of an image carrier by containing a developer composed of a toner and a carrier, comprising: a developing cartridge that forms at least a portion of a developer delivery path; a toner concentration detection sensor that detects the toner concentration of the developer contained within the developing apparatus; and a positioning mechanism that engages with an engaging portion formed at the center of a sensor main portion of the toner concentration detection sensor to determine the position of the sensor main portion in the developing cartridge.
[0009] According to the present invention, a developing apparatus, a processing cartridge, and an image forming apparatus can be provided to accurately determine the position of a toner concentration detection sensor relative to the developing cartridge at a desired position. Attached Figure Description
[0010] Figure 1 The diagram shown is an overall configuration diagram of the image forming apparatus in an embodiment of the invention.
[0011] Figure 2 The diagram shown is a configuration diagram of the imaging unit.
[0012] Figure 3 The image shown is a schematic cross-sectional view of the developing apparatus as seen along its length.
[0013] Figure 4 (A) shows the direction along Figure 3 Direction A represents the developing chamber, and direction B shows the direction along the developing chamber. Figure 3 The B direction represents the sensor holding component of the toner concentration detection sensor.
[0014] Figure 5 The image shown is a cross-sectional view of the sensor holding component that holds the toner concentration detection sensor in the developing chamber.
[0015] Figure 6 The image shown is an enlarged cross-sectional view of a modified example 1, in which a sensor holding component for maintaining the toner concentration detection sensor is positioned in the developing chamber.
[0016] Figure 7 The image shown is an enlarged cross-sectional view of a modified example 2, in which a sensor holding component for maintaining the toner concentration detection sensor is placed in the developing chamber.
[0017] Figure 8 (A) and (B) are enlarged cross-sectional views of a modified example 3 in which a sensor holding component for maintaining the toner concentration detection sensor is placed in the developing chamber.
[0018] Figure 9 The image shown is an enlarged cross-sectional view of a modified example 4, in which a sensor holding component for maintaining the toner concentration detection sensor is positioned in the developing chamber. Detailed Implementation
[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in the drawings, the same or equivalent parts are given the same reference numerals, and detailed descriptions thereof are omitted where appropriate.
[0020] First, through Figure 1 The overall structure and operation of the image forming apparatus 1 will be explained.
[0021] exist Figure 1 In the diagram, 1 is a serial color copier that serves as an image forming device, 3 is an original document transport unit that transports the original to the original document reading unit, 4 is an original document reading unit that reads the image information of the original, and 5 is a paper tray that loads the output image.
[0022] Additionally, 7 is a paper feed section that houses sheet material P such as paper, 9 is a alignment roller that adjusts the feeding timing of sheet material P, and 11Y, 11M, 11C, and 11BK represent photosensitive drums that serve as image carriers for forming toner images of various colors (yellow, magenta, cyan, and black).
[0023] Additionally, 13 refers to a developing apparatus for developing electrostatic latent images formed on the surfaces of each photosensitive drum 11Y, 11M, 11C, 11BK, and 14 refers to a primary transfer bias roller that overlays and transfers toner images formed on each photosensitive drum 11Y, 11M, 11C, 11BK onto a sheet P.
[0024] Additionally, 17 represents an intermediate transfer belt that overlaps and transfers toner images of multiple colors, 18 represents a secondary transfer bias roller used to transfer the colored toner images on the intermediate transfer belt 17 onto the sheet P, 20 represents a fixing device for fixing the unfixed image on the sheet P, and 28 represents toner containers of various colors (yellow, cyan, magenta, black) that supply toner (toner particles) to the developing apparatus 13.
[0025] The following describes the operation of a typical color image formation process in an image forming apparatus.
[0026] Additionally, the imaging process performed on the surface of photosensitive drums 11Y, 11M, 11C, and 11BK can also be referred to... Figure 2 .
[0027] First, the original document is transported from the document stage by the transport rollers of the document transport unit 3 and then placed on the contact glass of the document reading unit 4. Then, in the document reading unit 4, the image data of the original document placed on the contact glass is optically read.
[0028] In detail, the document reading unit 4 scans the image of the document on the contact glass while illuminating it with light from an illumination lamp. Then, the light reflected from the document is imaged on a color sensor using a mirror assembly and a lens. The color image data of the document is read in the color sensor according to the RGB (red, green, blue) color decomposition and converted into electrical image signals. Furthermore, based on the RGB color decomposition image signals, the image processing unit performs color transformation, color correction, and spatial frequency correction processing to obtain yellow, magenta, cyan, and black color image data.
[0029] Then, image data of yellow, magenta, cyan, and black are sent to the writing unit. Then, laser L (referencing) from the writing unit, based on the image data of each color... Figure 2The surfaces of the corresponding photosensitive drums 11Y, 11M, 11C, and 11BK are respectively irradiated.
[0030] On the other hand, the four photosensitive drums 11Y, 11M, 11C, and 11BK rotate clockwise as shown in the figure. Then, firstly, the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK are in contact with the charging section 12 (see Figure 12). Figure 2 The opposing portions of the photosensitive drums 11Y, 11M, 11C, and 11BK are uniformly charged (charging process). Thus, a charged potential is formed on the photosensitive drums 11Y, 11M, 11C, and 11BK. Then, the charged surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK reach the irradiation positions of each laser L.
[0031] In the writing section, lasers L corresponding to the image signals from the four light sources are emitted separately after being assigned to each color. Each laser passes through other optical paths (exposure process) according to its yellow, magenta, cyan, and black color components.
[0032] A laser beam corresponding to the yellow component is irradiated onto the surface of the first processing cartridge 11Y from the left side of the paper. At this time, the yellow component laser beam is scanned along the rotation axis (main scanning direction) of the photosensitive drum 11 by a high-speed rotating faceted mirror. Thus, an electrostatic latent image corresponding to the yellow component is formed on the photosensitive drum 11Y after it has been charged at the charging roller 12.
[0033] Similarly, when the laser corresponding to the magenta component is irradiated onto the surface of the second photosensitive drum 11M from the left of the paper, an electrostatic latent image corresponding to the magenta component is formed. When the laser corresponding to the cyan component is irradiated onto the surface of the third photosensitive drum 11C from the left of the paper, an electrostatic latent image corresponding to the cyan component is formed. When the laser corresponding to the black component is irradiated onto the surface of the fourth photosensitive drum 11BK from the left of the paper, an electrostatic latent image corresponding to the black component is formed.
[0034] Subsequently, the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK, which have formed electrostatic latent images of various colors, reach positions facing the developing apparatus 13. Then, toners of various colors are supplied from the developing apparatus 13 to the photosensitive drums 11Y, 11M, 11C, and 11BK, and the latent images on the photosensitive drums 11Y, 11M, 11C, and 11BK are developed (developing process).
[0035] After the developing process, the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK reach positions facing the intermediate transfer belt 17. Here, a primary transfer roller 14 is provided in each of the facing portions to abut against the inner circumferential surface of the intermediate transfer belt 17. Then, at the position of the primary transfer roller 14, the toner images of each color formed on the photosensitive drums 11Y, 11M, 11C, and 11BK are sequentially and overlappingly transferred onto the intermediate transfer belt 17 (first transfer process).
[0036] Then, the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK after the transfer process reach positions facing the cleaning section 15. Then, at the cleaning section 15, the untransferred toner remaining on the photosensitive drums 11Y, 11M, 11C, and 11BK is recovered (cleaning process).
[0037] Afterwards, the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK pass through the static elimination section, thus completing a series of imaging processes in the photosensitive drums 11Y, 11M, 11C, and 11BK.
[0038] On the other hand, after the various colors of toner on the photosensitive drum 11 are transferred by overlapping, the intermediate transfer belt 17 moves counterclockwise in the figure and reaches a position opposite to the secondary transfer bias roller 18. Then, at the position opposite to the secondary transfer bias roller 18, the colored toner image placed on the intermediate transfer belt 17 is transferred onto the sheet P (secondary transfer process).
[0039] Afterwards, the surface of the intermediate transfer belt 17 reaches the intermediate transfer belt cleaning section. Then, the untransferred toner adhering to the intermediate transfer belt 17 is recycled to the intermediate transfer belt cleaning section, thus completing the series of transfer processes on the intermediate transfer belt 17.
[0040] Here, the sheet P, which is conveyed between the intermediate transfer belt 17 and the secondary transfer bias roller 18 (secondary transfer clamping part), is conveyed from the paper supply part 7 via the alignment roller 9 and the like.
[0041] In detail, starting from the paper feeding section 7 that holds the sheet P, the sheet P fed by the paper feeding roller 8 is guided to the alignment roller 9 after passing through the transport guide section. When the sheet P reaches the alignment roller 9 and is aligned, it is transported toward the secondary transfer clamping section.
[0042] Then, the sheet P with the full-color image transferred is guided to the fixing device 20. In the fixing device 20, the color image is fixed onto the sheet P at the clamping point of the fixing roller and the pressure roller.
[0043] Then, the sheet P after the fixing process is discharged from the device body 1 as an output image by the paper discharge roller and stacked on the paper discharge tray 5, thus completing a series of image forming processes.
[0044] Next, refer to Figure 2 , Figure 3 The processing unit 10 (image forming unit) in the image forming apparatus will be described in detail below.
[0045] Figure 2The diagram shown is a configuration diagram of the processing cartridge 10 (image processing unit), which is a view from a cross section orthogonal to the rotation axis of the photosensitive drum 11. Figure 3 The figure shown is a schematic cross-sectional view (vertical cross-sectional view) of the developing apparatus 13 viewed from the length direction.
[0046] Furthermore, since the structures of each imaging unit are basically the same, therefore... Figure 2 The Latin letters (Y, C, M, Bk) for the symbols of the processing cartridge and developing device are omitted in Figures 3, etc.
[0047] like Figure 2 As shown, the processing cartridge is a unit that integrates the photosensitive drum 11 (which serves as the image carrier), the charging unit 12 (and the cleaning roller 22), the developing unit 13, and the cleaning unit 15, and is designed to be removable from the image forming apparatus body 100. Then, when the processing cartridge 10 reaches the end of its service life, it is removed from the image forming apparatus body 100 and replaced with a new processing cartridge.
[0048] The photoreceptor drum 11, which serves as the image carrier, is a negatively charged organic photoreceptor and is driven to rotate clockwise by a rotation drive mechanism.
[0049] The charging section 12 is an elastic charging roller formed on a mandrel by depositing a medium-resistance foamed urethane layer composed of urethane resin, carbon black as conductive particles, vulcanizing agent, foaming agent, etc. The medium-resistance layer material of the charging section 12 can also be a rubber material in which conductive substances such as carbon black or metal oxides for adjusting impedance are dispersed in urethane, ethylene propylene diene monomer (EPDM), nitrile rubber (NBR), silicone rubber, isoprene rubber, etc., or a material obtained by foaming these materials.
[0050] The cleaning roller 22 is configured to abut against the charging section 12 (charging roller) to clean foreign objects attached to the surface of the charging section 12.
[0051] The cleaning section 15 is equipped with a cleaning scraper that slides in contact with the photosensitive drum 11 to mechanically remove and recover untransferred toner on the photosensitive drum 11.
[0052] The developing apparatus 13 (developing section) is configured such that the developing roller 13a, which serves as a developer carrier, is positioned opposite the photosensitive drum 11 through an opening (formed in the developing cartridge 13k) with a small gap between them. A developing area is formed in the opposing portion where the photosensitive drum 11 and the magnetic brush (the developer G in a vertical position) come into contact. The developing apparatus 13 contains the developer G (a two-component developer) composed of toner T and carrier C. The developing apparatus 13 then develops the electrostatic latent image formed on the surface of the photosensitive drum 11 (forming a toner image). The configuration and operation of the developing apparatus 13 will be described in detail later.
[0053] Reference Figure 1 The toner container 28 contains toner T for supplying to the developing apparatus 13.
[0054] Specifically, based on the toner concentration detection sensor 13m (refer to) installed in the developing unit 13 by a magnetic sensor or the like, Figure 2 The information of the detected toner concentration (the proportion of toner in the developer G) is used to transfer the toner from the toner container 28 into the developing apparatus 13 via the toner delivery tube from the supply port 13d (see reference). Figure 3 To supply appropriate amounts of colorant T.
[0055] The developing apparatus 13 in the image forming apparatus will now be described in detail.
[0056] Reference Figure 2 , Figure 3 The developing apparatus 13 comprises a developing roller 13a as a developer carrier, a supply screw 13b1 as a first conveying component, a conveying screw 13b2 as a second conveying component, a thickness limiting scraper 13c as a developer limiting component, a partition component 13e as a wall portion, a developing cartridge 13k covering the developing apparatus 13, and a toner concentration detection sensor 13m. The developing roller 13a, supply screw 13b1, conveying screw 13b2, thickness limiting scraper 13c, partition component 13e, and other components are housed within the developing cartridge 13k (shell). Furthermore, the developing cartridge 13k can also be considered a cartridge component that at least forms part of the developer conveying path (first and second conveying paths B1, B2).
[0057] The developing roller 13a, which serves as the developer carrier, is constructed by forming a cylindrical sleeve 13a2 from non-magnetic materials such as aluminum, brass, stainless steel, and conductive resin. This sleeve, along with the supply screw 13b1 and the conveying screw 13b2, is driven by a rotary drive mechanism to... Figure 2 Rotate in the direction indicated by the arrow. (Refer to...) Figure 3Inside the sleeve 13a2 of the developing roller 13a, a magnet 13a1 forming multiple magnetic poles is fixedly disposed on the circumferential surface of the sleeve 13a2. The developer G carried on the developing roller 13a rotates in a predetermined direction ( Figure 2 The developer is conveyed by the counterclockwise rotation of the developing roller 13a to the position of the thickness limiting scraper 13c (developer limiting member). Then, the developer G on the developing roller 13a is limited to an appropriate amount at this position and conveyed to the position opposite to the photosensitive drum 11 (developing area). Then, by the electric field (developing electric field) formed in the developing area, the toner is adsorbed into the latent image formed on the photosensitive drum 11.
[0058] Reference Figure 2 The thickness-limiting scraper 13c, serving as a developer-limiting component, is a plate-shaped member arranged facing upwards from the developing roller 13a. Then, the developing roller 13a moves along... Figure 2 Rotating clockwise, the photosensitive drum 11 along Figure 2 Rotate clockwise.
[0059] Furthermore, in this embodiment, a reverse development method is used where the developing roller 13a rotates in the opposite direction to the rotation direction of the photosensitive drum 11 in the developing region. In contrast, a development method in which the developing roller 13a rotates in the same direction as the photosensitive drum 11 in the developing region can also be used.
[0060] Two conveying components (supply screw 13b1 and conveying screw 13b2) carry the developer G contained in the developing apparatus 13 along the length direction. Figure 2 The vertical direction of the paper surface, Figure 3 The mixing is carried out in a circular motion (left and right direction). Both the supply screw 13b1 and the conveying screw 13b2 are screw components with helical ribs wound around their shafts.
[0061] The supply screw 13b1, which serves as the first conveying component, is arranged opposite to the developing roller 13a below it. While conveying the developer G from one end of the length direction to the other end of the length direction, it supplies developer to the developing roller 13a and recovers the developer that has separated from the developing roller 13a.
[0062] In detail, the supply screw 13b1 (first conveying component) is positioned below the developing roller 13a, facing it. Then, the developer G is horizontally conveyed along its length (rotation axis direction). Figure 3 (As indicated by the dashed arrow, conveying from right to left), developer G is supplied to the developing roller 13a at the pick-up magnetic pole position, and at the developer separation magnetic pole position, the developer G that has detached from the developing roller 13a and fallen is conveyed axially downstream. The supply screw 13b1 along... Figure 2 Rotate clockwise within.
[0063] The conveying screw 13b2, which serves as the second conveying component, is arranged facing downwards from the supply screw 13b1 (the first conveying component), conveying the developer G from one end in the length direction to the other end in the length direction, and together with the supply screw 13b1, forming a circulation path for the developer G.
[0064] Specifically, the conveying screw 13b2 (second conveying component) is positioned obliquely below the supply screw 13b1, opposite the developing roller 13a across the supply screw 13b1. Then, in the second conveying path B2, the developer G (e.g., ...) is horizontally conveyed in the longitudinal direction. Figure 3 As indicated by the dashed arrow, the feed is from left to right. Furthermore, in this embodiment, the rotation direction of the feed screw 13b2 is set to be opposite to the rotation direction of the supply screw 13a. Figure 2 (counterclockwise direction).
[0065] Then, the developer circulates from the axial downstream side of the first transport path B1 of the supply screw 13b1 through the second connecting portion 13g (second relay portion) in the transport screw 13b2. Then, the transport screw 13b2 transports the developer G through the first connecting portion 13f (first relay portion). Figure 3 The conveying path (indicated by the dashed arrow) is fed to the axial upstream side of the first conveying path B1 of the supply screw 13b1.
[0066] Both the supply screw 13b1 and the transport screw 13b2 are arranged approximately horizontally with their rotation axes in the same manner as the developing roller 13a and the photosensitive drum 11. Furthermore, both the supply screw 13b1 and the transport screw 13b2 have a helical thread (formed as a single thread with a predetermined screw spacing) wound spirally on their shaft portions. Additionally, to ensure stable delivery of the developer, the number of helical threads can be multiple, particularly the supply screw 13b1.
[0067] In addition, the first conveying path B1 of the supply screw 13b1 and the second conveying path B2 of the conveying screw 13b2 are separated by the partition member 13e (wall).
[0068] Reference Figure 3 The upstream side of the first conveying path B1 of the supply screw 13b1 and the downstream side of the second conveying path B2 of the supply screw 13b2 are connected via a first connecting portion 13f. The developer G that reaches the downstream side of the second conveying path formed by the supply screw 13b2 is retained near the first connecting portion 13f and bulges, and is conveyed (supplied) to the upstream side of the first conveying path B1 formed by the supply screw 13b1 via the first connecting portion 13f.
[0069] Additionally, refer to Figure 3 The downstream side of the first conveying path B1 of the supply screw 13b1 and the upstream side of the second conveying path B2 of the supply screw 13b2 are connected via the second connecting portion 13g. Then, the developer G that reaches the downstream side of the first conveying path B1 of the supply screw 13b1 (developer G that was not supplied to the developing roller 13a in the first conveying path B1, or developer G that detached from the developing roller 13a at the fourth magnetic pole position and fell) falls down the second connecting portion 13g due to its own weight and reaches the upstream side of the second conveying path B2.
[0070] Furthermore, in the developing cartridge 13k (the portion corresponding to the second transport path B2), a toner concentration detection sensor 13m is provided, which detects the toner concentration of the developer G circulating within the developing apparatus 13, such as a magnetic sensor. Then, based on the toner concentration information detected by the toner concentration detection sensor 13m, fresh toner T is supplied from the toner container 28 to the developing apparatus 13 via the supply port 13d (located on the outer side in the longitudinal direction relative to the second connecting portion 13g) to ensure that the toner concentration is within the target range.
[0071] Additionally, refer to Figure 3 The toner supply port 13d is located above the upstream side of the second conveying path B2 of the conveying screw 13b2, and is positioned away from the developing area (outside the length of the developing roller 13a). Then, new toner T discharged from the toner container 28 is appropriately supplied into the developing apparatus 13 through the supply port 13d. Figure 3 (Replenishment in the direction of the white arrow). In this way, by placing the replenishment port 13d near the second connecting part 13g, the developer G supplied by its own weight from the second connecting part 13g in the second transport path B2 can be sufficiently dispersed and mixed over a relatively long period of time.
[0072] In addition, in this embodiment, the supply port 13d is arranged in the second conveying path B2, but the position of the supply port 13d is not limited to this. For example, the first conveying path B1 can be extended along the length direction and arranged above the downstream side.
[0073] Furthermore, known developers can be used as the developer G used in this embodiment.
[0074] For example, as toner T (the toner in developer G, the toner in toner container 28), a small-diameter toner with a volume average particle size of about 5.8 μm can be used as a polymer toner.
[0075] In addition, as the carrier C in the developer G, a small-diameter carrier with a weight average particle size of 20 to 60 μm can be used.
[0076] The following describes the features, configuration, and operation of the developing apparatus 13 in this embodiment.
[0077] As previously used Figure 2 As explained above, the developing apparatus 13 of this embodiment is provided with at least a developing cartridge 13k that forms a part of the developer transport path (first and second transport paths B1, B2) and a toner concentration detection sensor 13m that detects the toner concentration of the developer G housed inside the developing apparatus 13.
[0078] Furthermore, in this embodiment, the toner concentration detection sensor 13m is a magnetic sensor that detects the toner concentration of the developer G using a magnetic method. Also, the developer cartridge 13k is formed of a non-magnetic resin material or the like.
[0079] Here, as Figure 2 , Figure 4 , Figure 5 As shown, in the developing apparatus 13 of this embodiment, the sensor holding member 13r that holds the toner concentration detection sensor 13m is held in the developing cartridge 13k.
[0080] In addition, the sensor holding member 13r is a roughly rectangular box-shaped member made of non-magnetic resin material or the like, and is detachably mounted on the developing cartridge 13k by fastening with screws 90 to cover the toner concentration detection sensor 13m.
[0081] In addition, the sensor holding member 13r is fixed and held by the tightening of screws (not shown) or the like, and is installed or removed relative to the developing apparatus 13 together with the toner concentration detection sensor 13m during manufacturing or maintenance.
[0082] Furthermore, although not shown in the diagram, a connector for the wiring harness of the toner concentration detection sensor 13m is exposed in the sensor holding member 13r. Then, when the sensor holding member 13r is attached to or detached from the developing cartridge 13k, this connector connects to and disconnects from the cartridge-side connector of the developing cartridge 13k.
[0083] Furthermore, such as Figure 4 , Figure 5As shown, a protrusion 13s1 serving as a positioning mechanism is provided in the developing apparatus 13. This protrusion 13s1 engages (fits into) a hole 13n1, which serves as an engaging part, in the center of the sensor main part 13n (which has a detection surface, performs the central function of the sensor, and directly affects the accuracy of the sensor) formed in the toner concentration detection sensor 13m, thereby determining the position of the sensor main part 13n in the developing cartridge 13k.
[0084] The protrusion 13s1, which serves as the positioning mechanism, is formed on the mounting surface 13s of the developing cartridge 13k and can engage with the hole 13n1 (a through hole with a circular cross-section in this embodiment) of the sensor main body 13n. In other words, in addition to the protrusion 13s1, the hole 13n1 of the sensor main body 13n also functions as a positioning mechanism.
[0085] Furthermore, the mounting surface 13s of the developing cartridge 13k is a rectangular plane opposite the toner concentration detection sensor 13m, which has a generally rectangular shape, and a protruding portion 13s1 protrudes vertically on the side away from the developing cartridge 13k. Thus, in this embodiment, the toner concentration of the developer G in the developing apparatus 13 is detected via the toner concentration detection sensor 13m (sensor main portion 13n) through the developing cartridge 13k (mounting surface 13s).
[0086] Furthermore, in this embodiment, the sensor main portion 13n is formed in the shape of a coil or a ring. That is, the sensor main portion 13n is a generally cylindrical component with a hole 13n1 formed in the center as an engaging portion.
[0087] Thus, in the developing apparatus 13 of this embodiment, since a protrusion 13s1 is provided on the developing cartridge 13k (setting surface 13s) that engages with the hole 13n1 (engaging part) formed in the center of the sensor main portion 13n of the toner concentration detection sensor 13m, the position of the toner concentration detection sensor 13m (sensor main portion 13n) relative to the developing cartridge 13k (setting surface 13s) is precisely determined to be in the desired position. Therefore, during manufacturing or maintenance, whenever the toner concentration detection sensor 13m is mounted on the developing cartridge 13k together with the sensor holding member 13r, the undesirable situation where the position of the toner concentration detection sensor 13m (sensor main portion 13n) relative to the developing cartridge 13k deviates from the desired position is mitigated. Therefore, it is difficult for fluctuations to occur in the toner concentration detected by the toner concentration detection sensor 13m and the toner replenishment control based on the detection result.
[0088] In particular, in this embodiment, with the protrusion 13s1 of the developing cartridge 13k fitted into the hole 13n1 formed in the center of the sensor main portion 13n, the toner concentration detection sensor 13m and the sensor holding member 13r are fixed together on the developing cartridge 13k. Therefore, even if the toner concentration detection sensor 13m (sensor holding member 13r) is mounted on the developing cartridge 13k while rotating around the protrusion 13s1, the sensor main portion 13n can be positioned in the desired position with high precision.
[0089] In addition, since the direction in which the hole 13n1 and the protrusion 13s1 fit together is consistent with the direction in which the toner concentration detection sensor 13m (sensor holding member 13r) is mounted and dismounted relative to the developing cartridge 13k, its mounting and dismounting capability is also improved.
[0090] In addition, in this embodiment, the hole portion 13n1 of the sensor main portion 13n is set as a through hole, but the hole portion 13n1 can also be set as a non-through hole (concave hole portion).
[0091] Here, refer to Figure 4 , Figure 5 In the developing apparatus 13 of this embodiment, first and second protrusions 13k1 and 13k2 are provided in the developing cartridge 13k as a second positioning mechanism for determining the position of the sensor holding member 13r in the length direction.
[0092] In detail, two first protrusions 13k1 (with an internal thread formed in the center) are provided on the developing cartridge 13k such that they sandwich the setting surface 13s. Furthermore, a second protrusion 13k2 is provided on the developing cartridge 13k such that it is adjacent to one of the first protrusions 13k1.
[0093] On the other hand, the sensor holding member 13r has a first through hole 13r1 (screw hole) at a position corresponding to each of the two first protrusions 13k1. Furthermore, the sensor holding member 13r has a second through hole 13r2 (fitting hole) at a position corresponding to the second protrusion 13k2.
[0094] Then, as Figure 5 As shown, with the protrusion 13s1 engaged with the hole 13n1 and the second protrusion 13k2 engaged with the second through hole 13r2, the position of the sensor holding member 13r relative to the development cartridge 13k in the longitudinal direction is determined by screwing the screw 90 into the internal thread of the first protrusion 13k1 through the first through hole 13r1. In other words, with the protrusion 13s1 (hole 13n1) as the center, the sensor holding member 13r (toner concentration detection sensor 13m) is fixedly held on the development cartridge 13k in a non-rotational manner.
[0095] Furthermore, in this embodiment, since the fitting of the protrusion 13s1 and the hole 13n1 is the primary positioning, it is preferable that the positioning of the first and second protrusions 13k1, 13k2 and the first and second through holes 13r1, 13r2 is subordinate, thereby not affecting the fitting of the protrusion 13s1 and the hole 13n1. Specifically, relative to the internal thread diameter or protrusion diameter of the first and second protrusions 13k1, 13k2, it is preferable that the diameter of the first and second through holes 13r1, 13r2 is relatively loose.
[0096] <Variation Example 1>
[0097] like Figure 6 As shown, in Modification 1, the developing apparatus 13 has a protrusion 13r3 in the sensor holding member 13r that is engaged with the protrusion 13s1 of the developing cartridge 13k in the hole 13n1 (engaging part) of the sensor main part 13n.
[0098] In detail, the protrusion 13r3 is a convex member with a circular cross-section, formed to protrude vertically toward the sensor main part 13n on the inner wall surface of the sensor holding member 13r. Then, with the protrusion 13r3 inserted into the hole 13n1 of the sensor main part 13n, the toner concentration detection sensor 13m (sensor main part 13n) is positioned relative to the sensor holding member 13r.
[0099] By configuring it in this way, the positional accuracy of the toner concentration detection sensor 13m (sensor main part 13n) relative to the sensor holding member 13r is improved, and thus the positional accuracy of the toner concentration detection sensor 13m (sensor main part 13n) relative to the developing cartridge 13k is also improved. Therefore, the positional accuracy of the sensor holding member 13r relative to the developing cartridge 13k can also be improved.
[0100] Additionally, in variation example 1, such as Figure 6 As shown, the protrusion 13s1 and the convex portion 13r3 are fitted together in the hole 13n1 in a manner that prevents them from contacting each other. That is, a gap is provided between the front end of the protrusion 13s1 and the front end of the convex portion 13r3 in the hole 13n1. With this configuration, it is possible to suppress the undesirable situation where the protrusion 13s1 and the convex portion 13r3 come into contact with each other in the hole 13n1, causing deformation of the toner concentration detection sensor 13m and the sensor holding member 13r.
[0101] Then, in Modified Example 1, the position of the toner concentration detection sensor 13m (sensor main part 13n) relative to the developing cartridge 13k is also determined with high precision to the desired position.
[0102] <Variation Example 2>
[0103] like Figure 7 As shown, in the developing apparatus 13 of Modified Example 2, similar to Modified Example 1, a protrusion 13r3 that engages with the hole 13n1 (engaging part) is provided on the sensor holding member 13r.
[0104] Here, in Modification 2, the protrusion 13s1 of the developing cartridge 13k and the convex portion 13r3 of the sensor holding member 13r are configured to fit together in the hole 13n1 of the sensor main portion 13n.
[0105] Specifically, a shaft-shaped fitting portion 13s10 is formed at the front end of the protrusion 13s1, and a concave fitting portion 13r30 is formed at the front end of the convex portion 13r3, which is fitted by the fitting portion 13s10.
[0106] This configuration directly improves the positional accuracy of the sensor holding component 13r relative to the developing cartridge 13k.
[0107] Then, in Modified Example 2, the position of the toner concentration detection sensor 13m (sensor main part 13n) relative to the developing cartridge 13k is also determined with high precision to the desired position.
[0108] <Variation Example 3>
[0109] like Figure 8 As shown in (A), in the modified example 3, the developing apparatus 13 has an insertion part 13r4 (a through hole) formed in the sensor holding member 13r, which is inserted into the front end of the protrusion 13s1 that engages with and passes through the hole 13n1 (engaging part) of the sensor main part 13n.
[0110] Specifically, the protrusion 13s1 of the developing cartridge 13k is formed to be sufficiently long than the depth of the hole 13n1 (which is a through hole), and its front end protrudes to the outside through the insertion part 13r4 of the sensor holding member 13r (the part surrounded by the dotted line).
[0111] In addition, such as Figure 8 As shown in (B), the insertion portion 13r4 of the sensor holding member 13r can also be configured as a non-through hole (concave hole) so that the front end of the protrusion 13s1 is not exposed to the outside.
[0112] Through such Figure 8 The configurations shown in (A) and (B) can directly improve the positional accuracy of the sensor holding component 13r relative to the developing cartridge 13k.
[0113] Then, in Modified Example 3, the position of the toner concentration detection sensor 13m (sensor main part 13n) relative to the developing cartridge 13k is also determined with high precision to the desired position.
[0114] <Variation Example 4>
[0115] like Figure 9 As shown, the positioning mechanism of the developing apparatus 13 in Modified Example 4 for determining the position of the toner concentration detection sensor 13m (sensor main part 13n) relative to the developing cartridge 13k is different from that in the aforementioned embodiment.
[0116] like Figure 9 As shown, the positioning mechanism in Modification 4 consists of a shaft portion 13r5 (a protruding part with a circular cross-section) and an insertion fitting portion 13k5 (a non-through hole (concave hole portion) with a circular cross-section). The shaft portion 13r5 is formed on the sensor holding member 13r in a way that it can fit into the hole portion 13n1 of the sensor main portion 13n. The insertion fitting portion 13k5 is formed on the developing cartridge 13k in such a way that the front end of the shaft portion 13r5, which fits into and passes through the hole portion 13n1, can be inserted and fitted.
[0117] Even with this configuration, the position of the toner concentration detection sensor 13m (sensor main part 13n) relative to the developing cartridge 13k is determined with high precision at the desired position. Furthermore, the positional accuracy of the sensor holding part 13r relative to the developing cartridge 13k can be directly improved.
[0118] As described above, the developing apparatus 13 in this embodiment is a developing apparatus that contains a developer G composed of a toner T and a carrier C, and develops a latent image formed on the surface of a photosensitive drum 11 (image carrier). It is equipped with a developing cartridge 13k that forms at least a portion of the transport paths B1 and B2 of the developer G, and a toner concentration detection sensor 13m that detects the toner concentration of the developer G contained inside the developing apparatus 13. Furthermore, a protrusion 13s1 (positioning mechanism) is provided to engage with a hole 13n1 (engaging portion) formed in the center of the sensor main portion 13n of the toner concentration detection sensor 13m, thereby determining the position of the sensor main portion 13n within the developing cartridge 13k.
[0119] Therefore, the position of the toner concentration detection sensor 13m (sensor main part 13n) relative to the developing cartridge 13k can be determined with high precision at the desired position.
[0120] Furthermore, in this embodiment, the present invention is applied to the developing apparatus 13, which is configured as one of the components of the processing cartridge 10. However, the application of the present invention is not limited thereto, and the present invention can be applied even if the developing apparatus 13 is configured as a unit that can be attached to and detached from the main body of the image forming apparatus.
[0121] Here, in this application, "processing cartridge" is defined as a unit that is detachable from the image forming apparatus body after being integrated with at least one of the following: a charging unit (charging device) for charging an image carrier, a developing device (developing unit) for developing a latent image formed on the image carrier, and a cleaning unit (cleaning device) for cleaning the image carrier.
[0122] In addition, in this embodiment, the hole 13n1, which serves as the engaging part, in the center of the sensor main part 13n of the toner concentration detection sensor 13m is configured to engage with a positioning mechanism (engaged part) such as the protrusion 13s1 or shaft part 13r of the developing cartridge 13k. However, the relationship between the "engaged part" and the "engaged part" is not limited to this. For example, the "engaged part" may be a concave part (or a convex part), and the "engaged part" may be a convex part (or a concave part).
[0123] Then, even in such a case, it is possible to obtain essentially the same effect as in this embodiment.
[0124] Furthermore, this invention is not limited to this embodiment. Within the scope of the technical concept of this invention, it is obvious that appropriate modifications can be made to this embodiment beyond what is taught in this embodiment. In addition, the number, position, shape, etc., of the constituent components are not limited to this embodiment, and suitable numbers, positions, shapes, etc., can be selected when implementing this invention.
[0125] Alternatively, the method in this invention may also be a combination of notes 1 to 11 as shown below.
[0126] (Postscript 1)
[0127] A developing apparatus for developing a latent image formed on the surface of an image carrier by containing a developer composed of a toner and a carrier, characterized in that it comprises: a developing cartridge, which at least forms part of a developer delivery path; a toner concentration detection sensor for detecting the toner concentration of the developer contained inside the developing apparatus; and a positioning mechanism that engages with an engaging portion formed in the central part of a sensor main portion of the toner concentration detection sensor to determine the position of the sensor main portion in the developing cartridge.
[0128] (Postscript 2)
[0129] According to Appendix 1, the developing apparatus is characterized in that: the positioning mechanism has a protrusion formed on the developing cartridge, which can engage with a hole in the main part of the sensor that serves as the engaging part.
[0130] (Note 3)
[0131] The developing apparatus according to Appendix 2 is characterized by comprising: a sensor holding member held on the developing cartridge while holding the toner concentration detection sensor, the sensor holding member having a protrusion that engages with the hole from a side opposite to the protrusion that engages with the hole.
[0132] (Postscript 4)
[0133] According to Appendix 3, the developing apparatus is characterized in that the protrusion and the convex portion are fitted together in the hole in a manner that they do not contact each other.
[0134] (Note 5)
[0135] According to Appendix 3, the developing apparatus is characterized in that the protrusion and the convex portion are fitted together in the hole.
[0136] (Note 6)
[0137] The developing apparatus according to Appendix 2 is characterized by comprising: a sensor holding member held on the developing cartridge while holding the toner concentration detection sensor, the sensor holding member having an insertion portion for inserting into the front end of the protrusion that fits into and passes through the orifice.
[0138] (Note 7)
[0139] The developing apparatus according to Appendix 1 is characterized by comprising: a sensor holding member held on the developing cartridge while holding the toner concentration detection sensor, the positioning mechanism having a shaft portion formed on the sensor holding member, the shaft portion being capable of engaging with a hole portion of the sensor main body serving as the engaging portion, and an insertion engaging portion formed on the developing cartridge, such that the front end portion of the shaft portion engaging with and passing through the hole portion can be inserted into engagement.
[0140] (Note 8)
[0141] The developing apparatus according to any one of Appendices 3 to 7 is characterized by having a second positioning mechanism in the developing chamber for determining the position of the sensor holding member in the longitudinal direction.
[0142] (Note 9)
[0143] The developing apparatus according to any one of Appendices 1 to 8 is characterized in that: the main part of the sensor is formed in the shape of a coil or a ring.
[0144] (Postscript 10)
[0145] A processing cartridge that is detachable relative to the main body of an image forming apparatus is characterized by having integrally formed a developing apparatus and an image carrier as described in any one of Appendices 1 to 9.
[0146] (Postscript 11)
[0147] An image forming apparatus, characterized in that it comprises a developing apparatus as described in any one of Appendices 1 to 9 and the image carrier.
Claims
1. A developing apparatus for developing a latent image formed on the surface of an image carrier by containing a developing agent composed of a toner and a carrier, characterized in that... include: A developer cartridge, which at least forms part of the developer delivery path; A toner concentration detection sensor detects the toner concentration of the developer contained inside the developing apparatus; A positioning mechanism engages with a locking portion formed in the center of the sensor main body of the toner concentration detection sensor to determine the position of the sensor main body in the developing cartridge, wherein the positioning mechanism has a protrusion formed on the developing cartridge that can engage with a hole in the sensor main body that serves as the locking portion; as well as While holding the toner concentration detection sensor, a sensor holding member is held on the developing cartridge, wherein the sensor holding member has a protrusion that engages with the hole from a side opposite to the protrusion that is fitted into the hole.
2. The developing apparatus according to claim 1, characterized in that: The protrusion and the convex portion are fitted together in the hole in a manner that they do not contact each other.
3. The developing apparatus according to claim 1, characterized in that: The protrusion and the convex portion fit together in the hole.
4. The developing apparatus according to claim 1, characterized in that... include: The sensor holding component is held on the developing cartridge while the toner concentration detection sensor is being held in place. The sensor holding component has an insertion portion for inserting into and passing through the front end of the protrusion.
5. A developing apparatus for developing a latent image formed on the surface of an image carrier by containing a developing agent composed of a toner and a carrier, characterized in that... include: A developer cartridge, which at least forms part of the developer delivery path; A toner concentration detection sensor detects the toner concentration of the developer contained inside the developing apparatus; A positioning mechanism engages with a locking portion formed at the center of the sensor main body of the toner concentration detection sensor, thereby determining the position of the sensor main body within the developing cartridge; and The sensor holding component is held on the developing cartridge while the toner concentration detection sensor is being held in place. The positioning mechanism has a shaft portion formed on the sensor holding member, which can engage with a hole portion of the sensor main body that serves as the engaging portion, and an insertion engagement portion formed on the developing cartridge, such that the front end of the shaft portion that engages with and passes through the hole portion can be inserted and engaged.
6. The developing apparatus according to claim 1 or 5, characterized in that: The device has a second positioning mechanism that determines the position of the sensor holding member in the longitudinal direction within the developing chamber.
7. The developing apparatus according to claim 1 or 5, characterized in that: The main part of the sensor is formed in the shape of a coil or a ring.
8. A processing cartridge that is detachable from the main body of an image forming apparatus, characterized in that: It integrally comprises the developing apparatus and image carrier as described in claim 1 or 5.
9. An image forming apparatus, characterized in that: It has the developing apparatus and image carrier as described in claim 1 or 5.