Toner conveying equipment

Abstract

A colorant conveying device includes: a storage portion, which is configured to store colorant used by a developing device; an injection port, which is used to output the colorant from the storage portion; a conveying path unit, which includes a receiving portion, which receives the colorant ejected from the injection port and constitutes a conveying path for conveying the colorant to the developing device; a pump, which is used to output the colorant retained in the storage portion from the injection port toward the conveying path unit; and an optical sensor unit, which is arranged in a passing area, the colorant output from the injection port to the conveying path unit by the pump passes through the passing area, and the optical sensor unit detects whether there is colorant.

Description

Technical Field

[0001] The present invention relates to a toner conveying device. Background Art

[0002] An image forming apparatus (such as a printer, a copier, and a fax machine) that forms an image by forming a toner image using an electrophotographic system is equipped with a developer supply device in a developing device to supply developer consumed by image formation. The developer supply device stores a certain amount of developer taken out from a developer container in a storage unit (hopper), and operates a conveying device to supply the developer from the storage unit to the developing device at a required time.

[0003] Patent document 1 (Japanese Patent No. 5762052) proposes a configuration in which toner taken out from a toner bottle as an example of a developer container is held in a low-capacity hopper and conveyed to a developing device using a screw conveying mechanism at a required time. According to Patent document 1, it is necessary to continuously store and maintain a constant amount of toner in a storage unit so that the screw conveying mechanism can stably supply the toner. In this way, the control unit in the imaging device according to Patent document 1 uses an optical sensor to detect the surface height of the toner in the storage unit, and controls the amount of toner replenished from the toner bottle to the storage unit based on the information. Summary of the invention

[0004] In Patent Document 1, toner is output from a toner bottle used as a developer container to a storage unit, and then the toner is replenished from the storage unit to a developing device via a conveying path. The remaining amount of toner is detected using an optical sensor that detects whether toner exists at a predetermined height in the storage unit. Thus, even if there is no toner in the developer container, the system will determine that toner remains as long as the toner remains in the storage unit. Therefore, even when the developer container is empty or nearly empty, the system takes a certain amount of time to determine that no toner remains.

[0005] In view of the above problems, an object of the present invention is to provide a technology for quickly determining that a developer container holding toner is empty or almost empty.

[0006] The present invention provides a toner conveying device, comprising:

[0007] a storage portion configured to store toner used by the developing device;

[0008] an ejection port for outputting toner from the storage portion;

[0009] a conveying path unit including a receiving portion that receives the toner ejected from the ejection port and is configured to constitute a conveying path for conveying the toner to the developing device;

[0010] a pump for outputting the toner held in the storage portion from the ejection port toward the conveying path unit; and

[0011] An optical sensor unit is disposed in a passage area through which the toner output from the ejection port to the conveying path unit by the pump passes, and detects the presence or absence of the toner.

[0012] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1A and Figure 1B They are a plan view and a cross-sectional view of the upstream conveying section, respectively.

[0014] Figure 2 It is an overall cross-sectional view of the imaging device.

[0015] 3A to 3D are perspective views of the toner replenishment box as viewed from one end of the toner replenishment box.

[0016] FIG. 4A to FIG. 4C It is a diagram showing a mechanism for driving a pump.

[0017] Figure 5 is an exploded perspective view of a toner replenishment cartridge.

[0018] Figure 6 is a perspective view showing the overall configuration of the toner conveying device.

[0019] Fig. 7A and 7B are side and cross-sectional views of a portion of a toner conveying device.

[0020] FIG. 8A to FIG. 8C is a diagram showing toner output from a cartridge.

[0021] Fig.9A and 9B is a diagram showing the behavior of output toner; and

[0022] Fig.10 is a diagram showing the arrangement of the optical sensor with respect to a passing area through which output toner passes. DETAILED DESCRIPTION

[0023] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that unless otherwise specified, the scope of the present invention is not intended to be limited to the size, material, shape, relative arrangement, etc. of the constituent elements described in this embodiment.

[0024] First embodiment

[0025] The overall structure of the equipment

[0026] Will refer to Figure 2 An example of a configuration of an image forming apparatus 1 to which a toner conveying apparatus according to the present invention is applied and an image forming operation will be described with reference to an overall cross-sectional view of FIG.

[0027] The image forming apparatus 1 is an apparatus that forms an image on a recording material 4 using image forming units 6 (6Y, 6M, 6C, and 6K). The letters Y, M, C, and K attached to the reference numerals represent four colors of yellow, magenta, cyan, and black, respectively. The following description will omit these letters, and when there is no need to particularly distinguish between colors, the image forming units will be simply referred to as "image forming units 6."

[0028] The imaging unit 6 according to the present embodiment is a process cartridge. The imaging unit 6 (6Y, 6M, 6C, and 6K) includes a photosensitive drum 7 (7Y, 7M, 7C, and 7K), a charging device 8 (8Y, 8M, 8C, and 8K), a developing device 9 (9Y, 9M, 9C, and 9K), and a cleaning blade 10 (10Y, 10M, 10C, and 10K).

[0029] Each photosensitive drum 7 is rotatably supported by a frame member of the corresponding image forming unit 6. The developing device 9 is provided with developing rollers 11 (11Y, 11M, 11C, and 11K), and each developing roller 11 is configured to be able to contact and separate from the corresponding photosensitive drum 7. The developing roller 11 is rotationally driven to supply toner (developer) from the developing device 9 to the photosensitive drum 7.

[0030] The control unit 60 includes a CPU, a memory (collectively referred to as a volatile memory and a non-volatile memory), an input / output I / F, a bus, etc., and performs various processes by communicating with an optical sensor unit 115, a display unit 90, etc. (described later), and external devices such as an external information processing device (a personal computer, a smart phone, etc.). The control unit 60 also receives image data by communicating with the outside, reads out the received image data from the memory, and controls various constituent elements of the imaging device 1 to form an image based on the image data. The control unit 60 is a control unit composed of a control circuit, an information processing device, etc. The power supply unit 70 is a high-voltage power supply that supplies power to various constituent elements of the imaging device 1 (such as a charging device 8 and a laser scanner unit 12). The drive unit 80 is a driving power supply for driving various constituent elements of the imaging device 1, and is a motor for rotationally driving the photosensitive drum 7, the developing roller 11, the upstream side screw 105, the downstream side screw 124, the drive coupling 203, and various other types of rollers. The display unit 90 is a display device for providing information to the operator, and any display device, such as a liquid crystal panel, can be used. The display unit 90 may be configured as a touch panel so as to be able to accept operation input.

[0031] In the image forming operation, the control unit 60 forms a latent image based on the image data by causing each charging device 8 to charge the surface of the corresponding photosensitive drum 7, and then irradiating the surface of the photosensitive drum with laser light using the laser scanner unit 12. Then, the latent image on the surface of the photosensitive drum is visualized as a toner image by supplying toner to the photosensitive drum 7 through the developing roller 11. The developed toner image is transferred to the intermediate transfer belt 18 at the primary transfer portion 20. The Y, M, C, and K toner images are continuously transferred to form a four-color toner image on the surface of the intermediate transfer belt 18. The four-color toner image is conveyed to the secondary transfer portion 17 by the rotating intermediate transfer belt 18.

[0032] The toner replenishing boxes 13 (13Y, 13M, 13C, and 13K), the toner conveying devices 14 (14Y, 14M, 14C, and 14K), and the toner conveying driving devices 15 (15Y, 15M, 15C, and 15K) are arranged below the imaging units 6 (6Y, 6M, 6C, and 6K), respectively. Each toner conveying device 14 serves as a conveying path unit, and is driven by the corresponding toner conveying driving device 15 as the toner is consumed by the imaging unit 6, thereby conveying and replenishing the toner from the toner replenishing box 13 to the imaging unit 6.

[0033] The cassette 2 is provided at the lower part of the image forming apparatus 1, and a recording material 4 of paper or the like is held in the cassette 2. The cassette feeding portion 3 separates and feeds one sheet of the recording material 4 at a time by rotating, and the sheet is conveyed downstream by a resist roller 5.

[0034] The intermediate transfer unit 16 is disposed above the developing device 9. The intermediate transfer unit 16 includes an intermediate transfer belt 18, a primary transfer roller 19, a stretching roller, etc. The intermediate transfer unit 16 can be removed from the image forming apparatus itself. The intermediate transfer unit 16 is arranged approximately horizontally so that the secondary transfer portion 17 faces the conveying path of the recording material 4.

[0035] The intermediate transfer belt 18, which is opposed to the photosensitive drum 7, is an endless belt capable of rotation and is stretched over a plurality of stretching rollers. On the inner surface of the intermediate transfer belt 18, primary transfer rollers 19 (19Y, 19M, 19C, and 19K) are arranged opposed to the photosensitive drums 7 (7Y, 7M, 7C, and 7K), respectively, with the intermediate transfer belt 18 located between the primary transfer rollers 19 and the photosensitive drums 7. Primary transfer portions 20 (20Y, 20M, 20C, and 20K) are formed between the primary transfer rollers 19 and the photosensitive drums 7. At each primary transfer portion 20, a voltage is applied to the primary transfer rollers 19, and a toner image is transferred from the photosensitive drum 7 to the intermediate transfer belt 18.

[0036] The intermediate transfer belt 18 is interposed between the secondary transfer opposing roller 31 forming the secondary transfer portion 17 and the secondary transfer roller 21 as the secondary transfer member. The toner image transferred onto the intermediate transfer belt 18 is secondarily transferred onto the recording material 4 at the secondary transfer portion 17. The toner that cannot be completely transferred onto the recording material 4 during the secondary transfer and thus remains on the intermediate transfer belt 18 is removed by the cleaning unit 22. The toner removed by the cleaning unit 22 is conveyed to the toner collecting container 24 via the collecting toner conveying unit 23 and accumulated in the toner collecting container 24.

[0037] After undergoing the secondary transfer of the toner image, the recording material 4 is further transferred downstream (at Figure 2 The recording material 4 is conveyed to the discharge roller pair 26 and discharged to the discharge tray 27. The foregoing series of operations is an image forming operation for forming an image on the surface of the recording material.

[0038] Construction for toner replenishment

[0039] Next, the toner replenishing box 13 as the characteristic structure of the present embodiment and the structure for conveying the toner will be described with reference to Figures 3A to 4C. Figure 3A is a perspective view of the toner replenishing boxes 13Y, 13M and 13C. In Figures 3A to 3D, the direction indicated by the arrow B is the insertion direction of the toner replenishing box 13 installed in the main body of the imaging device. On the contrary, the direction opposite to the arrow B is the direction of removing the toner replenishing box 13 from the main body of the imaging device. Figure 3B is a perspective view of the state in which the side cover 224 is removed from the box shown in Figure 3A. Figure 3C is a perspective view of the toner replenishing box 13K, and Figure 3D is a perspective view of the state in which the side cover 224 has been removed from the box shown in Figure 3C.

[0040] FIG. 4A to FIG. 4C is a diagram showing the configuration of a cam for outputting toner, and shows one end of a toner replenishment box. Figure 4A 2 is a diagram showing the configuration of the cam gear 220 , the link mechanism 221 , and the pump 223 . Figure 4B yes Figure 4A Cross-sectional view of the structure shown. Figure 4C 2 is a development view of the cam groove 220 a in the cam gear 220 .

[0041] As shown in Figures 3A to 3D, the colorant replenishing box 13 includes a substantially rectangular replenishing frame member 201 having a longer direction and a shorter direction. The replenishing frame member 201 is capable of accommodating toner therein. The drive coupling 203, the cam gear 220, the connecting rod mechanism 221, the pump 223 and the screw gear 226 are arranged on the downstream side of the colorant replenishing box 13 along the installation direction (the direction shown by the arrow B) and are covered by the side cover 224. The discharge baffle 207 provided with the discharge port 208 is arranged on the bottom surface side (the lower side when in the normal use orientation). The gear portion of the cam gear 220 is meshed with the screw gear 226, and the screw gear 226 receives the rotational driving force from the cam gear 220. In this way, the screw gear 226 rotates together with the cam gear 220.

[0042] The drive coupling 203 is configured to transmit the driving force to the cam gear 220 and the toner replenishing screw 209 located in the replenishing frame member 201. When the toner replenishing box 13 is installed in the image forming apparatus 1, the drive coupling 203 is engaged with the main body side drive coupling (not shown). As a result, the driving force from the drive unit 80 is transmitted to the toner replenishing box side.

[0043] like FIG. 4A to FIG. 4C As shown, the cam gear 220 is provided with a cam groove 220a, and the cam protrusion 221a of the link mechanism 221 cooperates with the cam groove 220a. Both ends of the link mechanism 221 are guided by guide members 224a and 224b of the side cover 224 and supported so as to be able to reciprocate relative to the side cover 224 in the direction indicated by the arrow C (see Figure 5 ).like Figure 5 As shown, guides 224a and 224b correspond to the protruding portion of the side cover 224. A space is formed in the protruding portion, and the ends 221a and 221b of the link mechanism 221 are arranged in the space. Therefore, the position of the link mechanism 221 is limited by the guides 224a and 224b, so that the link mechanism 221 can move in the direction shown by the arrow C, but the rotational movement of the link mechanism 221 around the axis 500 is limited. The cam groove 220a is provided with a peak 220b inclined to the downstream side in the installation direction (the direction of the arrow B) and a valley 220c inclined to the upstream side in the installation direction (the direction of the arrow B). According to this structure, when the cam gear 220 rotates, the cam protrusion 221a assembled into the cam groove 220a alternately passes through the peak 220b and the valley 220c. As a result, the rotational movement of the gear is converted into the forward and backward movement of the link mechanism, which causes the link mechanism 221 to move back and forth in the installation direction (the direction shown by the arrow B).

[0044] Here, one end of the pump 223 in the installation direction is connected to the link mechanism 221 through the coupling portion 223b. The other end of the pump 223 in the installation direction is fixed to the replenishing frame member 201 through the connecting portion 223c. In addition, the internal space 223d of the pump 223 is communicated with the internal space of the replenishing frame member 201 (i.e., the toner storage chamber 201a which serves as a storage portion and stores toner) via the connecting portion 223c.

[0045] According to this configuration, the connecting portion 223c of the pump 223 is fixed to the supplementary frame member 201, and therefore, when the connecting portion 223b of the pump 223 moves back and forth in conjunction with the link mechanism 221, the bellows portion 223a of the pump 223 expands and contracts (see Fig. 8A and 8B ). This expansion and contraction causes the volume of the internal space 223d of the pump 223 to change, and as a result, the internal pressure of the toner storage chamber 201a communicating with the internal space 223d fluctuates. This imparts kinetic energy to the toner, and the toner is discharged from the discharge port 208. Note that the output device is not limited to the pump, and any device can be used as long as it can output the toner by imparting kinetic energy.

[0046] Figure 6 1 shows the overall configuration of the toner conveying device 14 provided in the image forming apparatus. Note that Figure 6 A part of the shape of the toner conveying device 14 is omitted to show the internal structure thereof. The structure of the toner conveying device 14 is roughly divided into an upstream side conveying portion 100 and a downstream side conveying portion 120 .

[0047] A feed port 101 is formed in the upper surface of the upstream side conveying portion 100. The toner supplied from the toner replenishing box 13 passes through the feed port 101, and is supplied to the storage container 108 in the upstream side conveying portion 100. The upstream side conveying portion 100 includes an upstream side screw 105, which is arranged to be covered by the storage container 108. The toner dropped from the feed port 101 is distributed over the entire area where the upstream side screw 105 is arranged. Then, the toner is conveyed in a direction toward the downstream side conveying portion 120 by the upstream side screw 105, which is rotationally driven by the upstream side driving gear 103.

[0048] The downstream conveying section 120 includes a downstream wall surface 123. The downstream screw 124 is arranged so as to be covered by the downstream wall surface 123. The most upstream portion ( Figure 6 The toner conveyed by the upstream conveying portion 100 is conveyed to the downstream screw 124. The downstream screw 124 is rotationally driven by the downstream driving gear 122 and conveys the toner in the direction opposite to the gravity direction. The toner conveyed by the downstream screw 124 is supplied to the developing device 9 through the main body discharge port 121.

[0049] Detailed description of the upstream conveying unit 100

[0050] Next, we will refer to Figure 1A , 1B 7A and 7B describe the toner conveying device 14 in detail. Figure 1A This is a diagram showing the upstream conveying section 100 from above. Figure 1B is along Figure 1A A cross-sectional view taken along line A1-A1 in FIG. Fig. 7A This is a diagram showing the upstream conveying section 100 from the side. Figure 7B It is along Fig. 7A A cross-sectional view taken along line A2-A2 in FIG.

[0051] like Figure 1BAs shown, the structure of the upstream conveying part 100 can be roughly divided into a storage container 108 and a storage container cover 109 used as a colorant receiving part. The storage container 108 and the storage container cover 109 are basically formed by a wall surface formed by at least one resin frame. The feed port seal 102 is fixed to the upper part of the feed port 101 formed in the storage container cover 109, and the feed port seal 102 seals the surrounding of the feed port 101 to prevent the colorant from scattering. The L-shaped channel 106 used as a toner channel is attached to the bottom of the feed port 101. The L-shaped channel 106 includes a roughly horizontal portion and a roughly vertical portion connected to the feed port 101, and the roughly horizontal portion connects the roughly vertical portion to the injection port 106a. Through this structure, the colorant that has been replenished from the feed port 101 is ejected toward the space S, which is located in the extension of the roughly horizontal portion of the L-shaped channel 106. In this way, the L-shaped channel 106 forms the injection port 106a. The ejected toner falls and accumulates at the bottom of the storage container 108 while passing through the passing area.

[0052] like Figure 7B As shown, a pair of light-transmitting members 107 serving as a pair of light-transmitting portions are attached to the side wall of the storage container 108 near the ejection port 106a in the L-shaped passage 106. In the present embodiment, the pair of light-transmitting members 107 are provided on both sides of the storage container 108 serving as a housing. The direction in which the pair of light-transmitting members 107 are connected intersects with the direction in which the toner is ejected from the ejection port 106a in the L-shaped passage 106 toward the space S in the toner passing region.

[0053] The optical sensor unit 115 includes a light-emitting substrate 115a serving as a light-emitting unit and including a light-emitting element and a driving circuit thereof, and a light-receiving substrate 115b serving as a light-receiving unit and including a light-receiving unit and a driving circuit thereof. The light-emitting substrate 115a of the optical sensor unit 115 is disposed outside one of a pair of light-transmitting members 107. The light-receiving substrate 115b is disposed outside the other light-transmitting member 107. In other words, the light-emitting substrate 115a, one of the light-transmitting members, the toner passing region, the other of the light-transmitting members, and the light-receiving substrate 115b are disposed in sequence in the direction connecting the pair of light-transmitting members 107. According to this structure, the optical path P from the light-emitting substrate 115a to the light-receiving substrate 115b intersects the toner passing region.

[0054] As a result, the toner can be detected by the optical sensor unit 115, which makes it possible to determine whether the toner exists. In other words, if there is no toner in the optical path P through which the light emitted from the light emitting substrate 115a reaches the light receiving substrate 115b via a pair of light transmitting members 107 under the control of the control unit 60, then since the light receiving substrate 115b has detected the light, the control unit 60 can determine that there is no toner. On the other hand, if the light is blocked by the toner and the light receiving substrate 115b cannot detect the light under predetermined conditions, the control unit 60 can determine that there is toner. Note that the control unit 60 can perform the determination based on the light intensity of the light reaching the light receiving substrate 115b.

[0055] For example, a light emitting diode (LED) that emits light such as infrared light may be used as a light emitting element included in the light emitting substrate 115a. However, the wavelength range of the light is not limited thereto, and the light may be visible light instead. Another light source member such as a semiconductor laser (LD) may be used instead of the LED. A known light receiving substrate (e.g., a light sensor) may be used as a light receiving unit included in the light receiving substrate 115b. Any other optical sensor may also be used as long as the sensor can determine whether an object is on the light path using light.

[0056] A material (e.g., acrylic resin) that is transmissive with respect to the wavelength range of light emitted from the light emitting substrate 115a may be preferably used as the light-transmitting member 107. The light-transmitting member 107 may have any shape and may be disposed at any position as long as a light path can be formed in a passing area through which the toner passes when falling, that is, it may be non-circular. In addition, in order to define the light path, an optical member such as a rod-shaped lens made of acrylic resin may be used as the light-transmitting member 107, or the optical member may be disposed near the light-transmitting member 107.

[0057] The light intensity of the light received by the light receiving substrate 115b when the light emitting substrate 115a emits light at a predetermined light intensity is pre-stored in the memory of the control unit 60. Then, by comparing the light intensity of the light received by the light receiving substrate 115b with the stored light intensity when emitting light, it is determined whether there is toner in the passing area. In other words, when the light receiving substrate 115b has received light with at least a predetermined optical intensity, the control unit 60 determines that there is no toner or there is almost no toner, and performs a predetermined process. Optionally, time information about the time when the light receiving substrate 115b receives light when the light emitting substrate 115a emits light at a predetermined light intensity is pre-stored in the memory of the control unit 60. In this case, it is determined whether there is toner in the passing area according to the length of time that the light receiving substrate 115b receives light within a predetermined time period exceeds a threshold time. In other words, when the light receiving substrate 115b has received light for at least a predetermined time, the control unit 60 determines that there is no toner or there is almost no toner, and performs a predetermined process.

[0058] Here, the predetermined process performed by the control unit 60 when it is determined that there is no toner or there is almost no toner includes, for example, displaying a message prompting replacement of the toner replenishment cartridge in the display unit 90 .

[0059] like Figure 7B As shown, in this embodiment, the injection port 106a in the L-shaped channel 106 has a square cross-sectional shape, and one side La is 3.5 mm. Figure 1B As shown, the L-shaped channel 106 has a vertical channel length Lb of 7.6 mm and a horizontal channel length Lc of 12.5 mm. Although the cross-sectional shape of the L-shaped channel 106 is described as a square in the present embodiment, another shape, such as a rectangle or a circle, may be used instead. The vertical and horizontal channel lengths may be changed according to the size, shape, etc. of the cross-sectional shape. It is desirable to set the cross-sectional shape to an optimal shape according to the size and arrangement of the light-transmitting member 107, the detection range of the optical sensor, etc.

[0060] Remaining amount detection method during operation performed when toner is replenished

[0061] Next, we will refer to Figures 8A to 8C 9A to 9B describe a method of detecting the remaining toner amount during an operation of replenishing toner from the toner replenishment box 13. Fig. 8A This is a diagram showing the interior of the toner replenishment box 13 from above. Figure 8B and Figure 8C is a cross-sectional view taken along line A3 - A3 , and shows the toner T. FIG. Figure 8B The pump 223 is shown in an expanded state, Figure 8C The pump 223 is shown in a deflated state. Figure 1B , Fig.9A and 9B is along Figure 1A A cross-sectional view taken along line A1-A1 in FIG. Fig.9A Corresponds to Figure 8B ,and Fig. 9B Corresponds to Figure 8C .

[0062] As described above, when the amount of toner remaining in the developing device decreases or decreases from a predetermined amount, the control unit 60 performs control to replenish the toner from the toner replenishment box 13 to the developing device 9. The control unit 60 obtains the amount of toner remaining in the developing device 9 by a given method such as optical detection or detection based on weight, and sends a replenishment signal to the toner conveying device side when the remaining amount reaches zero or drops below a predetermined threshold. Figure 8B and 8C As shown, when a replenishment signal is received on the toner conveying device side, the cam gear 220 arranged coaxially with the drive coupling 203 (not shown) and the pump 223 rotates, causing the pump 223 to be in an expanded state ( Figure 8B ) and contraction state ( Figure 8C ) repeatedly expands and contracts.

[0063] like Figure 8B As shown in FIG. 2 , the internal space 223d of the pump 223 and the toner storage chamber 201a are connected via the communication port 201b. Figure 8C When the toner storage chamber 201a is contracted as shown, the internal pressure of the toner storage chamber 201a increases, and the toner T that has been conveyed into the toner storage chamber 201a by the toner replenishing screw 209 can be discharged from the discharge port 208. Figure 8B and 8C As shown, in this embodiment, the diameter Φ of the pump is 42 mm, the length L1 in the no-load state (expanded state) is 20.1 mm, the length L2 in the contracted state is 8.1 mm, and the expansion / contraction stroke is 12 mm. One expansion / contraction cycle T of the pump is 0.38 seconds. With this pump shape and design specifications, the toner T can be discharged into the toner storage chamber 201a via the L-shaped passage 106 of the upstream conveying portion 100.

[0064] Next, we will refer to Fig.9A and 9B The supply of toner in the upstream side conveying portion 100 is described. Fig.9A shows a state where toner is not replenished from the toner replenishment box 13. Fig. 9B The state in which toner is being replenished from the toner replenishment box 13 is shown.

[0065] like Fig.9AAs shown, when toner is not replenished, a set amount of toner is retained in the storage container 108. The toner surface in the storage container 108 at this time is referred to as "toner surface Z". The toner surface Z is defined by the structure of the inner surface of the storage container 108, the construction and performance of the upstream side screw 105, etc. Fig.9A In the illustrated state, the light-transmitting member 107 and the toner surface Z do not overlap when viewed from the angle shown in the figure.

[0066] When toner replenishment starts, the status changes to Fig. 9B 106a in the L-shaped passage 106. Here, the trajectory along which the toner discharged from the ejection port 106a in the L-shaped passage 106 falls to the toner surface Z in the storage container 108 will be referred to as a "toner falling trajectory K". The upper and lower ends of the toner falling trajectory K in the vertical direction are at Fig. 9B 106a and the toner surface Z. Assuming that the trajectory of the toner ejected from the upper end is the first trajectory and the trajectory of the toner ejected from the lower end is the second trajectory, the range surrounded by the first trajectory, the second trajectory, the ejection port 106a and the toner surface Z corresponds to the passing area through which the toner passes when falling after being ejected. When viewed from the angle shown in the figure, the light-transmitting member 107 is arranged to project onto at least one of the first trajectory and the second trajectory. Preferably, the light-transmitting member 107 is arranged to project onto both the first trajectory and the second trajectory.

[0067] Preferably, when projected onto the passing area as viewed from a direction intersecting the toner ejection direction, a pair of light-transmitting portions are arranged to overlap with an area enclosed within (i) the first trajectory, (ii) the second trajectory, (iii) a line connecting the upper and lower ends of the ejection port, and (iv) a wall surface of the receiving portion. This ensures that the optical path of the optical sensor overlaps with the toner passing area.

[0068] Looking at this from a different perspective, preferably, when the projection onto the passing area is viewed from a direction intersecting the toner ejection direction, the light receiving unit is arranged to overlap with the area enclosed within (i) the first trajectory, (ii) the second trajectory, (iii) the line connecting the upper and lower ends of the ejection port, and (iv) the wall surface of the receiving portion. This also ensures that the optical path of the optical sensor overlaps with the toner passing area.

[0069] With this construction, the optical sensor can detect the presence of the toner discharged from the ejection port 106a via the light-transmitting member 107. If the toner is not discharged from the ejection port 106a despite the replenishment operation, the control unit 60 can determine that the toner in the toner replenishment box 13 has been used up. This can quickly determine that there is no toner remaining in the developer container. Note that if the light-transmitting member 107 has a function for focusing light, and an optical member that reflects the focused light to a given position is also provided, the position of the light receiving unit of the light-emitting substrate 115a does not need to overlap with the toner falling trajectory when viewed from a direction intersecting with the toner ejection direction. On the other hand, if the light-transmitting member 107 does not have such a function, at least a portion of the light receiving unit of the light-emitting substrate 115a must overlap with the toner falling trajectory when viewed from a direction intersecting with the toner ejection direction.

[0070] Will refer to Fig.10 Consider the condition of determining whether there is toner using an optical sensor. Here, "no toner" refers to a state where no toner or almost no toner is discharged from the toner replenishment box. Alternatively, "no toner" refers to a state where the toner replenishment box is empty or almost empty. Fig.10 1 is a cross-sectional view showing a portion of the storage container 108 in an enlarged manner, and is a diagram for considering the path (track) that the discharged colorant may follow when falling, and the arrangement conditions that enable the optical sensor to detect the colorant when the colorant falls. As described above, by arranging the light receiving units of the light-transmitting member 107 and the light-emitting substrate 115a to overlap with the passing area defined by the upper and lower ends of the toner falling track K when viewed from the angle shown in the figure, the light path intersects with the toner passing area. However, it is noted that the light-transmitting member 107 and the light-emitting substrate 115a's light-receiving units do not necessarily have to be completely within the passing area. As long as the light passing through the light-transmitting member 107 can be detected by the optical sensor unit 115, it is sufficient to set the light receiving unit of the light-emitting substrate 115a to at least partially overlap with the passing area.

[0071] This embodiment assumes that the toner passes through the horizontal passage of the L-shaped passage 106 and is then ejected horizontally from the ejection port 106a. Assume that T1 represents the toner ejected from the lower end of the ejection port 106a, T2 represents the toner ejected from the upper end of the ejection port 106a, and T 1_0 (x1, z1) represents the coordinates of the toner T1 when it is ejected, T 2_0 (x1, z2) represents the coordinates of the toner T2 when ejected. It is also assumed that the toner ejection direction is the positive direction along the x-axis and the toner falling direction (vertically downward) is the positive direction along the z-axis.

[0072] Assuming that the initial velocity of the toner is V0m / s, the toner moves at a uniform speed of Vx=V0 in the horizontal direction and falls freely at a speed of Vz=gt in the vertical direction. At this time, the displacement from the initial coordinate t seconds after injection is (V0t, (1 / 2)gt 2 ), and the toner falling trajectory is given by z = (g / 2V0 2 )·x 2 Therefore, the coordinates of toner T1 t seconds after ejection are T 1_t (x1+V0t,z1+1 / 2·gt 2 ), and the coordinate of toner T2 is T 2_t (x1+V0t,z2+1 / 2·gt 2 ).

[0073] For the toner ejected from the ejection port 106a, the range of the falling trajectory is defined by assuming an initial velocity of uniform rectilinear motion at V0 m / s and free falling motion. This is based on the assumption that most of the toner ejected from the ejection port 106a is ejected as agglomerates adjacent to each other, so that the influence of air resistance can be ignored.

[0074] When spraying, it has T 1_0 The movement trajectory of the toner T1 of the coordinates of (x1, z1) can also be defined by the following formula. The coordinates of the toner T1 are expressed as follows:

[0075] X=x1+V0t...(1),

[0076] Z=(z1+1 / 2·gt 2 )…(2)

[0077] Using equations (1) and (2) and eliminating t, we can obtain the following equation (3).

[0078] Z=z1+1 / 2·g((X-x1) / V0) 2 …(3)

[0079] By appropriately substituting the value of X in the formula (3), the value of the Z coordinate of the toner ejected from the lower end of the ejection port 106a at any X coordinate can be obtained. In other words, the formula (3) represents the value of the Z coordinate at any X coordinate. Fig.10 The moving trajectory of the toner ejected from the lower end of the ejection port 106a in FIG. 1 is shown as a function of the X-axis.

[0080] Similarly, the following formula can be used to define the injection with T 2_0 The moving track of the toner T2 is represented by the coordinates of (x1, z2). The coordinates of the toner T2 are expressed as follows:

[0081] X=x1+V0t…(4),

[0082] Z=(z2+1 / 2·gt 2 )…(5)

[0083] Using equations (4) and (5) and eliminating t, we can obtain the following equation (6).

[0084] Z=z2+1 / 2·g((X-x1) / V0) 2 …(6)

[0085] By appropriately substituting the value of X in the formula (6), the value of the Z coordinate of the toner ejected from the upper end of the ejection port 106a at any X coordinate can be obtained. In other words, the formula (6) represents the value of the Z coordinate at any X coordinate. Fig.10 The moving trajectory of the toner ejected from the upper end of the ejection port 106a in FIG. 1 is shown as a function of the X-axis.

[0086] In this way, the above formulas (3) and (6) can define the toner passing area (passing trajectory) ejected from the ejection port 106a. In the configuration according to the present embodiment, the light transmitting member 107 is arranged so that the optical path of the optical sensor overlaps the toner passing area.

[0087] In this way, by ensuring that the light-transmitting member 107 and the light-receiving unit of the light-emitting substrate 115a at least partially fall within this range, the optical path P can be made to intersect the toner passing area. Preferably, as in the example shown here, the light-transmitting member 107 is arranged to cover the upper and lower ends of the toner passing area. By doing so, the optical sensor reliably detects any toner discharge, which improves the accuracy of detection.

[0088] Here, the initial speed V0 is a predetermined value determined by the toner characteristics (e.g., material and shape), the performance of the pump 223 (e.g., the cross-sectional area of ​​the pump 223 and the stroke during the back-and-forth movement), and the position and size of the ejection port 106a. In other words, the above-mentioned first trajectory and second trajectory are also determined by the toner characteristics (e.g., material and shape), the performance of the pump 223 (e.g., the cross-sectional area of ​​the pump 223 and the stroke during the back-and-forth movement), and the position and size of the ejection port 106a. In this way, the toner passing area after ejection can be calculated in advance using the above formula. Therefore, by arranging the light-transmitting member 107 in a manner overlapping with the toner passing area when projecting the light-transmitting member 107, it is possible to reliably detect whether there is toner residue.

[0089] The shape of the passage through which the toner output from the pump is ejected into the storage container 108 is not limited to an L shape. In addition, the method for ejecting the toner is not limited to horizontal ejection. For example, the toner may fall freely, or may be ejected at an angle. Even in this case, the light-transmitting member 107 and the optical sensor may be arranged according to the trajectory that the toner is expected to follow when falling.

[0090] As described above, according to the present invention, since the light-transmitting member is disposed near the path through which the toner passes, the discharged toner can be directly detected. This makes it possible to quickly determine that the toner in the toner replenishment box has run out or is nearly run out, thereby improving usability.

[0091] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A toner conveying device, comprising: a storage portion configured to store toner to be used by a developing device; a conveying path unit including a receiving portion that receives the toner from the storage portion and is configured to constitute a conveying path through which the toner is conveyed to the developing device; a pipe provided with an ejection port from which toner is ejected to the receiving portion of the conveying path unit; a pump configured to send out air for ejecting the toner stored in the storage portion from the ejection port toward the receiving portion of the conveying path unit; and An optical sensor unit including a light emitting element configured to emit light and a light receiving element configured to receive light, the optical sensor unit being arranged so that a light path from the light emitting element to the light receiving element intersects with a passing area, the optical sensor unit being configured to detect the presence of toner passing through the light path, wherein the toner ejected from the ejection port to the receiving portion of the conveying path unit through the air passes through the passing area after the toner is ejected from the ejection port of the tube and before the toner falls on a landing point of the receiving portion of the conveying path unit.

2. The toner conveying device according to claim 1, wherein: A pair of light-transmitting portions arranged side by side in a direction intersecting a toner ejection direction are provided in the housing of the conveying path unit, the light-emitting element is arranged at a position corresponding to one of the light-transmitting portions, and the light-receiving element is arranged at a position corresponding to the other light-transmitting portion; and Light traveling from the light emitting element to the light receiving element passes through the one light transmitting portion, the passing region, and the other light transmitting portion in sequence.

3. The toner conveying device according to claim 2, wherein: Assuming that in the passing area, the trajectory of the colorant ejected from the upper end of the ejection port is the first trajectory, and the trajectory of the colorant ejected from the lower end of the ejection port is the second trajectory, the light-transmitting portion is arranged so that when the light-transmitting portion is projected onto the passing area as viewed from a direction intersecting with the toner ejection direction, the light-transmitting portion overlaps with the area enclosed by the first trajectory, the second trajectory, the line connecting the upper and lower ends of the ejection port, and the wall surface of the receiving portion.

4. The toner conveying device according to claim 1, wherein: Assuming that in the passing area, the trajectory of the colorant ejected from the upper end of the ejection port is the first trajectory, and the trajectory of the colorant ejected from the lower end of the ejection port is the second trajectory, the light receiving element is arranged so that when the light receiving element is observed from a direction intersecting with the toner ejection direction and projected onto the passing area, the light receiving element overlaps with the first trajectory, the second trajectory, the line connecting the upper and lower ends of the ejection port, and the wall surface of the receiving portion.

5. The toner conveying device according to claim 1, wherein: The ejection port is formed by a toner passage through which toner is ejected from the storage portion, and the toner passage guides the toner from the storage portion and causes the toner to fall into the receiving portion of the conveying path unit.

6. The toner conveying device according to claim 5, wherein: The toner passage includes a substantially horizontal portion that ejects toner horizontally to the receiving portion of the conveying path unit.

7. The toner conveying device according to claim 6, wherein: The storage portion is arranged above the receiving portion of the conveying path unit; and The toner passage is an L-shaped passage including a substantially vertical portion that moves toner downward from the storage portion and a substantially horizontal portion that connects the substantially vertical portion to the ejection port, and ejects toner horizontally from the substantially horizontal portion toward the receiving portion of the conveying path unit.

8. The toner conveying device according to claim 3, wherein: The first trajectory and the second trajectory are based on the location of the injection port and the performance of the pump.

9. The toner conveying device according to claim 1, wherein: The conveying path unit includes: an upstream conveying portion that conveys toner in a horizontal direction; and a downstream conveying portion that is connected to the upstream conveying portion and conveys toner upward in a vertical direction; and The optical sensor unit is arranged in the upstream side conveying portion.

10. An imaging device comprising: a developing device storing toner; an image forming unit that forms an image using toner; Toner delivery equipment; and control unit, wherein When the amount of toner remaining in the developing device falls below a predetermined threshold, the control unit performs control to replenish the toner to the developing device using the toner conveying device; and The toner conveying device is the toner conveying device according to any one of claims 1 to 9.

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