Developer replenishing apparatus and image forming apparatus with rotational velocity control

A replenishing apparatus includes a rotatable cylindrical-shaped container having a discharge opening through which toner is discharged, and a guide member provided rotatably with the container. The guide member has a first face on an inner face of the container and a second face which guides the toner scooped by the first face toward the discharge opening. A controller controls a drive portion to rotate the container in a first mode that performs replenishment control in a first drive condition and in a second mode that performs replenishment control in a second drive condition in which a quantity of rotation of the container per unit time is less than the first drive condition. The controller switches the mode from the first mode to the second mode based on a detection result about a quantity of developer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer that forms an electrostatic image on an image bearing member, for example, by an electrophotographic system, an electrostatic recording system and the like to convert the electrostatic image into a visible image (toner image) by a developer contained in a developing device. In particular, the invention relates to an image forming apparatus to which the developer is replenished by rotation of a developer replenishment container, and a developer replenishing apparatus.

2. Description of the Related Art

An image forming apparatus, in which a developer (toner) is supplied to a developing device by rotating a cylindrical developer replenishment container in a laying-down state, has been put to practical use.

The presence or absence of the developer is determined by a developer detection sensor provided in a developer accommodation portion of a developer replenishing apparatus included in the image forming apparatus, and the enough developer to be used in the developing device is supplied from the developer replenishing apparatus. When the developer in the developer accommodation portion decreases, the “absence of developer” is determined by the developer detection sensor, and the developer replenishment container rotates. When the developer replenishment container rotates, the developer is replenished to the developer replenishing apparatus from a discharge opening portion, and when “the presence of developer” is determined by the developer detection sensor, the rotation of the developer replenishment container stops. During the replenishment operation of the developer, the developer replenishment container is continuously rotating.

Japanese Patent Laid-Open No. 2010-210946 discloses a configuration that has a discharge opening portion with an inner diameter smaller than an accommodation portion at one end portion of a cylindrical developer replenishment container, a developer in the developer replenishment container moves to the discharge opening portion side in accordance with the rotation of the developer replenishment container, and then the developer in the developer replenishment container is scooped up and conveyed to the discharge opening portion, by a conveying portion which rotates integrally with the developer replenishment container. By having the conveying portion, the developer remaining inside the container is reduced, without exceeding the height of the discharge opening portion.

In the configuration in which toner is scooped up and conveyed to the discharge opening portion by the conveying portion which rotates integrally with the cylindrical container as described above, the conveying portion has roles (a) and (b) described below. That is, there are (a) a role of scooping the developer accumulated near the discharge opening portion by a scooping portion, and (b) a role of conveying the scooped developer to the discharge opening portion, by sliding down a guide portion due to the own weight of the developer.

Moreover, in a case where the conveying portion rotates as described above, the developer existing in the container during a replenishment operation is broadly divided into (1) a developer that is scooped up and conveyed to the discharge opening portion by the conveying portion, and (2) a developer that remains in the container and is not conveyed to the discharge opening portion.

When classifying the developer described in (2), although the developer is scooped up by the conveying portion, there are a spilled developer, a developer that spills, rebounds, and floats in the container again, and a developer that starts to float by the impact of the spilled developer.

In the developer replenishment container having the conveying portion that scoops up the developer within the container as described above, when there is a large quantity of developer in the container, there is also a large quantity of developer accumulated in the discharge opening portion. Thus, it is possible to scoop up a lot of developer by one scooping operation (the role (a) of the conveying portion). Since the scooped developer slides down the guide portion and is conveyed at this time, a quantity of discharge also increases (the role (b) of the conveying portion). Since the scooping operation per unit time and the number of times, in which the developer slides down and is discharged, increase by performing the replenishment operation by the continuous rotation, the quantity of discharge increases. When the quantity of developer in the developer replenishment container is large, discharging properties are satisfactory by performing the replenishment operation by the continuous rotation.

On the other hand, when the quantity of developer in the container is small, that is, when there are many hollow portions inside the container, if the replenishment operation is continuously performed, the developer in the container is constantly stirred by the rotation of the container main body and the conveying portion, and thus a quantity of floating developer increases. As a result, since the quantity of developer to be scooped up by the scooping operation decreases, and the quantity of developer that slides down and is conveyed also decreases, discharging properties are lowered, and the quantity of developer remaining inside the container increases. Further, since the quantity of floating developer is unstable, the quantity of developer remaining inside the container varies. The increase and the variation of quantity of developer remaining inside the container become a problem because it leads to an increase in running costs.

SUMMARY OF THE INVENTION

It is desirable to provide a developer replenishing apparatus and an image forming apparatus capable of suppressing and reducing the variation in the quantity of developer remaining in the container.

A replenishing apparatus according to the present invention includes: a container which accommodates developer and is capable of discharging the developer by rotating; a guide portion which is provided so as to be rotatable with the container, and is able to scoop up the developer of a bottom portion of a first region in the container and guide the developer to a second region in which a height of a bottom surface is higher than the first region; a drive portion which rotates the container; a receiving portion which receives the developer discharged from the container; a detection portion which detects information about a quantity of developer within the receiving portion; and a controller which controls the drive portion based on a detection result of the detection portion, wherein the apparatus is able to execute, as drive conditions of the drive portion, a first mode that performs the replenishment control in a first drive condition, and a second mode that executes the replenishment control in a second drive condition in which a quantity of rotation of the container per unit time is less than the first drive condition, and the controller switches the mode from the first mode to the second mode, based on the detection result of the detection portion.

DESCRIPTION OF THE EMBODIMENTS

[First Embodiment] Exemplary embodiments of the invention will be illustratively described below in detail with reference to the drawings. However, as long as not described specifically in particular, a dimension, a material, a shape, a relative arrangement and the like of constituent components described in this embodiments are not intended to limit the scope of the invention only thereto.

<Overall Configuration of Image Forming Apparatus>FIG. 1is a schematic configuration diagram illustrating an example of a full-color image forming apparatus (full-color printer) having an inline type intermediate transfer belt (intermediate transfer portion) in an electrophotographic system of the embodiment.

The image forming apparatus includes four image forming portions (image forming stations) of an image forming portion1Y configured to form an image of yellow color, an image forming portion1M configured to form an image of magenta color, an image forming portion1C configured to form an image of cyan color, and an image forming portion1Bk configured to form an image of black color, and the four image forming portions1(1Y,1M,1C,1Bk) are arranged in a row at regular intervals.

In each image forming portion1, a drum-type electrophotographic photoreceptor (hereinafter, referred to as photosensitive drum)2(2a,2b,2c,2d) is installed as an image bearing member. A primary charger3(3a,3b,3c,3d), a developing device4(4a,4b,4c,4d), a transfer roller5(5a,5b,5c,5d) as a transfer portion, and a drum cleaning device6(6a,6b,6c,6d) are disposed around each photosensitive drum2, and a laser exposure device7is disposed on the lower side between the primary charger3and the developing device4.

A yellow toner, a cyan toner, a magenta toner, and a black toner are respectively accommodated in the developing devices4a,4b,4c, and4d.

Each photosensitive drum2is a negatively chargeable OPC photoreceptor, has a photoconductive layer on a drum substrate made of aluminum, and is rotated and driven at a predetermined process speed by a driving device (not illustrated).

The primary charger3as the primary charging portion uniformly charges the surfaces of each photosensitive drum2to a predetermined potential of negative polarity by a charging bias applied from a charging bias power source (not illustrated).

The developing device4is equipped with the toner, and attaches the toner of each color to each electrostatic image formed on each photosensitive drum2to develop the toner as a toner image (visible image).

The transfer roller5as the primary transfer portion is arranged so as to be enable to come into contact with each photosensitive drum2via the intermediate transfer belt8in each primary transfer portion32(32a,32b,32c,32d).

The drum cleaning device6has a cleaning blade or the like for removing the residual transfer toner remaining on the photosensitive drum2at the time of the primary transfer from the photosensitive drum2.

The intermediate transfer belt8is stretched among a secondary transfer counter roller10, a drive roller59and a tension roller11, and is rotated in a direction of arrow A by the driving input to the drive roller59. The secondary transfer counter roller10is arranged so as to be enable to come into contact with a secondary transfer roller12via the intermediate transfer belt8by a secondary transfer portion34. Furthermore, on the outer side of the endless intermediate transfer belt8, and in the vicinity of the tension roller11, a belt cleaning device13configured to remove and recover the residual transfer toner remaining on the surface of the intermediate transfer belt8is installed. Furthermore, a substantially vertical conveying path, in which a fixing device16having a fixing roller16aand a pressure roller16bis installed, is formed on the downstream side and the upper side of the conveying direction of a transfer material P than the secondary transfer portion34.

The exposure device7includes a laser beam emitting portion configured to perform the light emission corresponding to a time series electrical digital pixel signal of given image information, a polygon lens, a reflecting mirror and the like, and forms an electrostatic image of each color corresponding to the image information on the surface of each photosensitive drum2charged by each primary charger3, by performing the exposure to each photosensitive drum2.

Next, the image forming operation using the image forming apparatus described above will be described.

When an image formation starting signal is issued, each photosensitive drum2of each image forming portion1rotated and driven at a predetermined process speed is negatively charged uniformly by the primary charger3. Moreover, the exposure device7emits a color-separated image signal, which is input from the outside, from the laser beam emitting element to form an electrostatic image of each color on each photosensitive drum2via the polygon lens, the reflecting mirror or the like.

Moreover, first, the yellow toner is attached to the electrostatic image formed on the photosensitive drum2a, by the developing device4ato which the developing bias of the same polarity as the charge polarity (negative polarity) of the photosensitive drum2ais applied, to become a visible image as the toner image. The yellow toner image is primarily transferred onto the driving intermediate transfer belt8in the primary transfer portion32abetween the photosensitive drums2aand the transfer roller5a, by the transfer roller5ato which the primary transfer bias (opposite-polarity to the toner (positive polarity)) is applied.

The intermediate transfer belt8to which the yellow toner image is transferred is moved to the image forming portion1M side. Furthermore, even in the image forming portion1M, in the same manner as described above, a magenta toner image formed on the photosensitive drum2bis superimposed on the yellow toner image on the intermediate transfer belt8, and is transferred by the primary transfer portion32b.

At this time, the residual transfer toner remaining on each photosensitive drum2can be scraped off by a cleaner blade or the like provided in the drum cleaning device6, and is recovered.

Hereinbelow, in the same manner, the toner image of cyan and black formed by the photosensitive drums2cand2dof the image forming portions1C and1Bk are sequentially superimposed on the toner images of yellow and magenta superimposed and transferred on the intermediate transfer belt8by each primary transfer portion32to form a full-color toner image on the intermediate transfer belt8.

Moreover, in accordance with a timing when a leading end of the full-color toner image on the intermediate transfer belt8is moved to the secondary transfer portion34between the secondary transfer counter roller10and the secondary transfer roller12, the transfer material (sheet) P selected from a sheet cassette17or a manual feed tray20and fed though a conveying path18is conveyed to the secondary transfer portion34by a registration roller19. The full-color toner image is collectively and secondarily transferred to the transfer material P conveyed to the secondary transfer portion34, by the secondary transfer roller12to which the secondary transfer bias (opposite-polarity to the toner) is applied.

The transfer material P formed with the full-color toner image is conveyed to the fixing device16. After the full-color toner image is heated and pressurized by a fixing nip portion between the fixing roller16aand the pressure roller16band is thermally fixed onto the surface of the transfer material P, the full-color toner image is discharged onto the discharge tray22of the upper surface of the main body by the discharge roller21, and then a series of image forming operations finishes. In addition, the secondary transfer residual toner or the like remaining on the intermediate transfer belt8is removed and recovered by the belt cleaning device13.

<Developer Replenishing Apparatus>FIG. 2is a perspective view illustrating an example of a toner replenishing apparatus, andFIGS. 3A and 3Bare cross-sectional views thereof. First, the toner replenishing apparatus configured to supply the toner to the developing device4will be described.

A toner replenishing apparatus301provided in the image forming apparatus has a toner accommodation portion (buffer portion)302that stores the toner replenished from a tubular toner replenishment container70(70a,70b,70c,70d) in which a plurality of color toners corresponding to each developing device4is contained, a toner conveying member303that conveys the toner, and a toner residual quantity detection portion401that detects the residual quantity of toner in the toner accommodation portion302using light.

When shortage of toner is detected by the toner residual quantity detection portion401disposed in the toner accommodation portion302, the toner replenishment container (hereinbelow, referred to as “toner bottle”)70, which is a cylindrical bottle, is rotated and driven by a toner replenishment container drive portion (not illustrated), the toner of the interior is discharged into the toner accommodation portion302from a toner discharge port, and the interior of the toner accommodation portion302is filled with toner until the toner residual quantity detection portion401detects the presence of toner.

The toner supplied into the toner accommodation portion302is conveyed to a toner accommodation portion side opening portion306by the toner conveying member303, and is further conveyed to each developing device4from a developing device side opening portion307by a toner conveying member305of the toner conveying portion304.

(Developer Detection Configuration) Next, the toner residual quantity detection portion401configured to detect the residual quantity of toner in the toner accommodation portion302will be described. In addition, the detection of the residual quantity of toner of the embodiment is intended to detect the presence or absence of the toner, by detecting the height of the toner supplied to the toner accommodation portion302.

The toner residual quantity detection portion401provided in the toner replenishing apparatus301includes a light-emitting portion404that emits light, a light-receiving portion405that receives the light, a light-emitting side light transmitting member402that guides the emitted light into the toner accommodation portion302, and a light-receiving side light transmitting member403that guides light of the toner accommodation portion302to the light-receiving portion. An LED of the light-emitting portion404of the toner residual quantity detection portion401lights on, the detected light passes through the interior of the light-emitting side light transmitting member402formed by PS (Polystyrene) or PC (Polycarbonate) of transparent resin, is guided into the toner accommodation portion302, and is emitted from the vertical exiting surface of the light-emitting side light transmitting member402. At this time, if there is no toner between the light-emitting side light transmitting member402and the light-receiving side light transmitting member403disposed to face each other in the horizontal direction, the detected light is incident from a vertical incident surface of the light-receiving side light transmitting member403without being blocked, passes through the interior of the light-receiving side light transmitting member403, and is received by the light-receiving portion405, and the image forming apparatus detects that a predetermined quantity of toner is not present in the toner accommodation portion302. Then, the toner bottle70is rotated and driven by a toner bottle drive portion (not illustrated), and the toner of the interior is discharged into the toner accommodation portion302from the toner discharge port. By repeatedly discharging the toner from the toner bottle70and storing the toner in the toner accommodation portion302until the detected light is blocked between the light-emitting side light transmitting member402and the light-receiving side light transmitting member403, a predetermined quantity of toner is maintained in the toner accommodation portion302. In addition, in order to constantly keep the interior of toner accommodation portion302at a predetermined quantity of toner, in consideration of responsiveness to the variation of the quantity of toner, it is preferable that the toner residual quantity detection portion401be located immediately below the vicinity of the toner discharge port of the toner bottle70.

As mentioned above, in the toner replenishing apparatus301, the toner is supplied to the developing device4as needed together with the image formation, and the toner is kept at a predetermined quantity of toner by receiving the supply of new toner from the toner bottle70based on the detection result of the toner residual quantity detection portion401. For this reason, by quantitatively supplying the required quantity of toner calculated by a control unit of the image forming apparatus into the developing device4, it is possible to maintain a mixing ratio between the toner and the magnetic carrier in a predetermined state, in the developing device using a two-component developer, and the stable image formation is possible.

<Toner Discharge Configuration of Toner Bottle> Here, the discharge configuration of toner of the toner bottle70will be described with reference toFIGS. 3A to 6. As illustrated inFIGS. 3A and 3B, the toner bottle70of the embodiment has a cylindrical container body700configured to accommodate the toner, and a developer conveying portion701configured to convey the toner in the container main body to a discharge opening portion702by rotating integrally therewith. Moreover, a groove703having a helical shape is provided on the side surface of the toner bottle70. With the rotation of the toner bottle70, the toner is conveyed to the discharge opening portion702side along the helical shape.

The toner bottle70has a container main body configured to accommodate the toner, and the developer conveying portion701configured to convey the toner in the container main body to the discharge opening portion702by rotating integrally therewith. The developer conveying portion701includes a baffle portion that is rotated together with the toner bottle70, scoops up the toner located below the opening portion702to the upper side than the opening portion702, and guides the toner into the opening portion702. In other words, the baffle portion has a guide portion that guides the developer located in the bottom portion of a first region of the toner bottle to the bottom portion of a second region higher than the first region, on the opening portion702side of the toner bottle70.

Specifically, as illustrated inFIGS. 5A to 5D, the conveying portion701has a scooping portion701athat is provided in the vicinity of the discharge opening portion702to scoop up the toner in the container to the opening portion702, and a guide portion701bthat guides the scooped toner to the opening portion702.

The toner accumulated near the discharge opening portion702along a helical shape is scooped up by the scooping portion701aof the conveying portion701that rotates integrally with the toner bottle70(FIGS. 5A and 5B), is conveyed toward the discharge opening portion702by sliding down the guide portion701b, and is discharged to the toner accommodation portion302(FIGS. 5C and 5D). In addition, as illustrated inFIG. 6, as the toner in the toner bottle70during the rotation operation of the toner bottle70, there are a toner B that is stirred and floats by the rotation of the toner bottle70and the conveying portion701, and a toner A that is accumulated near the discharge opening portion702and is scooped up by the scooping portion701a.

<Toner Supply Mode from Toner Bottle> Although the image forming apparatus of the embodiment rotates the toner bottle70to supply the toner, as driving conditions that rotate the toner bottle70, there are a first driving condition, and a second driving condition in which a quantity of rotation of the toner bottle per unit time is lower than that of the first driving condition. Thus, as supply modes of the toner, there are a first supply mode in which the toner bottle70is rotated under the first driving condition, and a second supply mode in which the toner bottle70is rotated under the second driving condition. In the embodiment, the first supply mode is a method that continuously rotates the toner bottle70, and the second supply mode is a method that intermittently rotates the toner bottle70. Here, the continuous rotation means an operation that rotates continuously the toner bottle70without stopping, and the intermittent rotation means an operation that repeatedly performs the rotation/stop of the toner bottle70.

Moreover, in the image forming apparatus of the embodiment, when the quantity of toner in the toner bottle is large, since discharging properties of the toner are good, the continuous rotation is performed, and when the quantity of toner in the toner bottle decreases and discharging properties of the toner become worse, the intermittent rotation is performed in which the scoop-up interval using the scooping portion701abecomes longer than the continuous rotation.

(Toner Discharge Due to Continuous Rotation of Toner Bottle) First, when the toner bottle70is continuously rotated, discharging properties of the toner will be described with reference toFIGS. 7A to 8B.

As illustrated inFIGS. 7A and 7B, when the quantity of toner in the toner bottle is large, as the toner in the toner bottle, there is the toner B stirred and floating by the rotation of the toner bottle70and the conveying portion701, but there is also a lot of toner A accumulated near the opening portion of the toner bottle70. For this reason, it is possible to scoop up a sufficient quantity of toner by the scooping portion701aof the conveying portion701. Since the scooped-up toner is conveyed and discharged to the discharge opening portion702by sliding down the guide portion701b, the quantity of discharge to the toner accommodation portion302is also large (C ofFIG. 7B).

As the image formation is repeatedly performed and the number of times of the discharge from the toner bottle70to the toner accommodation portion302increases, the quantity of toner in the toner bottle decreases.

As illustrated inFIGS. 8A and 8B, when the quantity of toner in the toner bottle70decreases, in addition to a decrease in the total quantity of the toner in the toner bottle70, since there is the toner B that is stirred and floats by the rotation of the toner bottle70and the conveying portion701, the toner A accumulated near the opening portion of the toner bottle70decreases. For this reason, the toner scooped up by the scooping portion701aof the conveying portion701decreases. Since the scooped toner is conveyed and discharged to the discharge opening portion702by sliding down by the guide portion701b, the quantity of discharge to the toner accommodation portion302also decreases (C ofFIG. 8B). As the residual quantity of toner in the toner bottle70decreases, since the quantity of discharge to the toner accommodation portion302also decreases, eventually, the toner is hardly discharged.

(Toner Discharge Due To Intermittent Rotation of Toner Bottle) According to the image forming apparatus of the embodiment, even when the toner bottle70continuously rotates for a predetermined time, in a case where the presence of toner is not detected by the toner residual quantity detection portion in the toner accommodation portion302, it is determined that the residual quantity of toner in the toner bottle70is small. Moreover, in that case, the toner bottle70is switched to the intermittent rotation.

Here, discharging properties of the toner when intermittently rotating the toner bottle70will be described with reference toFIGS. 9A and 9B. When the quantity of toner in the toner bottle70is small, if the toner bottle70is intermittently rotated, the rotation stop time occurs in the toner bottle70. Accordingly, during the rotation operation of the toner bottle70, the toner B stirred and floating by the rotation of the toner bottle70and the conveying portion701falls free, and is deposited in the bottom portion of the toner bottle70(FIG. 9A→FIG. 9B).

Even in a case where the total quantity of toner in the toner bottle70is equal to that in the case of the continuous rotation, since the percentage of the floating toner B decreases, the toner A accumulated near the opening portion of the toner bottle70increases. Moreover, at the time of re-rotation, since the toner accumulated near the discharge opening portion702is scooped up by the scooping portion701aof the conveying portion701, the quantity of the scooped toner becomes larger compared to the case of the continuous rotation. Since the scooped toner slides down the guide portion701band is conveyed to the discharge opening portion, the quantity of discharge into the toner accommodation portion302also increases as compared to the case of the continuous rotation. It is preferred that the stop time of the intermittent rotation be equal to or greater than the time required for the free-fall of the floating toner B, that is, be equal to or greater than the time when the toner falls free by a distance of an inner diameter of the toner bottle70.

Even when the toner bottle70is intermittently rotated for a predetermined time, when the presence of toner is not detected by the toner residual quantity detection portion401configured to detect the residual quantity of toner in the toner accommodation portion302, it is determined that there is no toner in the toner bottle70. Moreover, in that case, the rotation operation of the toner bottle70is stopped, and a display portion (not illustrated) displays to promote the replacement of the toner bottle70.

FIG. 10illustrates a series of rotation operations of the toner bottle. When the quantity of toner in the toner bottle is large, the continuous rotation is performed (rotational speed V1). When the quantity of toner in the toner bottle decreases, even if the toner bottle continuously rotates for a predetermined time at V1, the presence of toner is not detected by the toner residual quantity detection portion401. Therefore, it is determined the residual quantity of toner is small, and the toner bottle70is switched to the intermittent rotation (rotational speed V2=0). Thereafter, even when the toner bottle70is intermittently rotated for a predetermined time, as long as the presence of toner is not detected by the toner residual quantity detection portion401, the intermittent rotation of the toner bottle70is stopped, and the replacement display of the toner bottle is performed.

<Toner Supply Control> Next, a description will be given of a drive control that switches the toner supply mode according to the residual quantity of toner in the toner bottle70.

FIG. 11is a block diagram of the controller which controls the driving control capable of executing the toner supply in the image forming apparatus of the embodiment. Driving of a toner bottle drive motor60serving as a drive portion configured to rotate the toner bottle70, and the control of the toner residual quantity detection portion401in the toner accommodation portion302are executed by a CPU10.

FIG. 12is a flowchart illustrating a toner supply procedure. When an instruction of the image formation is input, the image forming operation is started (S400). When the image forming operation is started, the presence or absence of toner is determined by the toner residual quantity detection portion (S402) until the image forming operation ends (S401). When the shortage of toner is determined, the toner is replenished to the accommodation portion, by rotating the toner bottle (S404) until the presence of toner is determined (S402). When the toner is supplied by the rotation of the toner bottle and the presence of toner is determined by the toner residual quantity detection portion, the rotation of the bottle stops (S403). At this time, since the quantity of toner in the toner bottle is large and the quantity of discharge is large, the replenishment operation is performed which continuously rotates the toner bottle.

In a case where the toner bottle is continuously rotated for a predetermined time or more and the shortage of toner is continuously determined (S405), the image forming operation is stopped (S406). At this time, it is determined that the residual quantity of toner in the toner bottle is small, and the rotation operation of the toner bottle is switched to the intermittent rotation (S407).

When the presence of toner is determined here (S408), the image formation resumes (S413). After the toner bottle is switched to the intermittent rotation, in a case where the toner bottle is intermittently rotated for a predetermined time or more (S409) and the shortage of toner is determined, it is confirmed that the toner bottle is in an empty state (S410). In that case, the intermittent rotation of the toner bottle is stopped (S411), and a replacement request of the toner bottle is displayed on a display portion501(S412). Moreover, the image formation is stopped (S414).

When the toner is supplied from the toner bottle70as described above, in a case where there is enough toner in the bottle, the toner is supplied by the continuous rotation of the bottle, and in a case where the residual quantity of toner in the bottle is small, the toner is supplied by the intermittent rotation of the bottle. It is possible to efficiently discharge the toner in the bottle, by switching the toner supply mode depending on the residual quantity of toner in the bottle in this way.

In addition, in the embodiment, although the image forming apparatus having the toner accommodation portion (buffer section)302configured to store the toner replenished from the toner replenishment container70(70a,70b,70c,70d) has been described as an example, the invention is not limited thereto. For example, instead of providing the toner accommodation portion (buffer portion)302, the invention is also applicable to a configuration in which the toner is directly replenished to each developing device4from the toner replenishment container70(70a,70b,70c,70d). In this case, the toner residual quantity detection portion is substitutable for an inductor sensor in the developing device, regardless of the presence or absence of the toner replenishing apparatus. Further, as another substitute portion, a configuration may be provided in which a sensor capable of detecting the presence or absence of the discharge from the toner bottle is provided or the residual quantity is detected based on the video count information. Furthermore, in the case of using the video count information, when the integrated value of the video count information exceeds a predetermined value, it is determined that the residual quantity of toner is small, and the bottle may be switched to the intermittent driving.

[Second Embodiment] In the first embodiment, the description has been given of an example in which, when the quantity of toner in the toner bottle is small, the quantity of toner remaining in the toner bottle is reduced by intermittently rotating the toner bottle. Here, regarding the discharge of toner in the toner bottle, by the rotation of the conveying portion integrally with the rotation of the toner bottle, the toner near the discharge opening portion is scooped up by the scooping portion and can slide down by the guide portion. Accordingly, the rotation time of the toner bottle is related to the discharge efficiency. In the second embodiment, the rotation time during the intermittent rotation of the toner bottle will be described with reference toFIGS. 5A to 5D, 13 and 14.

As described above, in the intermittent rotation of the toner bottle70, since the toner, which is stirred and floats by the rotation of the toner bottle70and the conveying portion701during the rotation operation, is deposited in the bottom portion of the toner bottle70by free-fall when the rotation is stopped, the toner accumulated near the discharge opening portion702also increases. For that reason, when the toner bottle rotates again, the quantity of toner scooped up by the scooping portion701aof the conveying portion701increases, the quantity of toner sliding down the guide portion701balso increases, and the quantity of toner conveyed to the discharge opening portion702also increases.

As the above-mentioned effect, in particular, during re-rotation, the quantity of toner first scooped up by the scooping portion701aof the conveying portion701increases. The quantity of toner, which rotates again and is scooped up after the second time by the scooping portion701aof the conveying portion701, becomes a situation close to the continuous rotation in the interior of the toner bottle70. For this reason, there is toner B which is stirred and floats by the rotation of the toner bottle70and the conveying portion701after the second time, and the toner A accumulated near the opening portion of the toner bottle70decreases. Accordingly, the quantity of scooping after the second time becomes less than the quantity of scooping of the first time.

Therefore, for the first time of the re-rotation, it is possible to improve the toner discharging properties of the toner scooped up by the scooping portion701aof the conveying portion701, by discharging the toner with low loss. That is, as the minimum rotation time of the intermittent rotation, by setting the rotation time to be equal to or greater than the time when the toner first scooped up by the scooping portion701ais able to slide down the guide portion701b, the discharging properties are improved. When the rotation time is equal to or less than that time, even when a lot of toner is scooped up by the scooping portion701afor the first time, the toner is stopped before sliding down the guide portion701b. In this case, when the conveying portion701is stopped, the toner is spilled from the upper part of the conveying portion701(FIG. 13), a loss increases and the discharging properties are degraded.

To be more specific, as illustrated inFIG. 5A, if the rotational angle of the conveying portion701when scooping up the toner by the scooping portion701ais assumed to be 0°, when the rotational angle exceeds 90°, the toner begins to slide down on the guide portion701b(FIG. 5B). Therefore, it is preferable to set the minimum rotation time in the intermittent rotation to the time required for the conveying portion701to perform a quarter rotation.

Next, the difference in discharging efficiency due to the posture of the conveying portion701when stopping will be described with reference toFIGS. 5A to 5D and 14.

As described above, if the rotational angle of the conveying portion701is assumed to be 0° when the scooping portion701astarts to scoop up the toner (FIG. 5A), in a region in which the rotational angle of the conveying portion701is 90° to 270° (FIG. 14), the inclination of the guide portion701bforms an angle with respect to the direction of the rotational axis. For this reason, the toner scooped up by the scooping portion701ais able to slide down on the guide portion701b. When stopped in this region, after the stop, since the toner is able to slide down on the guide portion701b, the discharging properties are satisfactory. On the other hand, only when the rotational angle of the conveying portion701is stopped at 90° and 270°, since the inclination of the guide portion701bdoes not form an angle with respect to the direction of the rotational axis, the toner on the guide portion701bcannot slide down, and the toner is not discharged. In other words, the discharging properties are the worst.

Therefore, in the embodiment, the rotation time of the intermittent rotation is set to the time or more required to perform the operation at least once that scoops up the toner by the scooping portion701aand delivers the scooped-up developer is passed to the guide portion. Further, in order to avoid the discharging properties of the toner from the toner bottle70from becoming worse, the time is set to the rotation time that prevents the toner bottle70from being always stopped in the same phase, and the conveying portion701is not always stopped at the rotational angle of 90° and 270°.

Thus, it is possible to increase the quantity of discharge efficiency due to scooping-up and sliding-down of the toner at the time of the intermittent rotation.

[Third Embodiment] Next, a third embodiment will be described below with reference toFIGS. 5A to 5D, and 14 to 16. As described above, when the toner is discharged by the conveying portion701, the rotational phase is related to the discharging properties. Therefore, in the third embodiment, a protrusion shape (not illustrated) is formed on the exterior of the toner bottle, a photo interrupter (not illustrated) configured to detect the protrusion shape is included, and a phase detection portion is included which detects the phase of the conveying portion701by detecting the rotational position of the toner bottle. Moreover, it is possible to directly control the phase of the conveying portion701using a detection result of the phase detection portion.

As described in the second embodiment, in order to improve the discharging properties of the toner in the intermittent rotation of the toner bottle70, it is preferable to continuously perform the scooping-up operation of the toner using the scooping portion701a, and the operation of causing the scooped-up toner to slide down by the guide portion701bonce. As illustrated inFIGS. 5A to 5D, after the toner is scooped up by the scooping portion701a, and after the rotational angle of the conveying portion701exceeds 90°, the toner starts to slide down by the guide portion701b. In the case of performing the phase control of the conveying portion701, it is preferable that the rotational angle of the minimum be 90° or more.

Here, a difference in discharging efficiency due to the posture of the conveying portion701when the rotation stops will be described. If the rotational angle of the conveying portion701when the scooping portion701astarts to scoop up the toner is assumed to be 0°, as described above, in the region in which the rotational angle of the conveying portion701is 90° to 270° (FIG. 14), the toner scooped up by the scooping portion701ais able to slide down on the guide portion701b. Therefore, when the conveying portion701is stopped in the region, the toner on the guide portion701befficiently slides down after stopping. In particular, when the rotational angle of the conveying portion701is stopped at 180° (FIG. 15), since the inclination of the guide portion701bforms the most angle relative to the direction of the rotational axis, force by which the toner on the guide portion701bslides down is maximized, and the discharge efficiency is the best.

Therefore, in the embodiment, the discharge efficiency is improved, by satisfying the minimum angle of rotation at the time of intermittent rotation of the toner bottle70, and by performing the phase control of the conveying portion701so that the guide portion701benters a position where the toner is guided substantially vertically and downward (for example, ±5° when stopping (FIG. 16A).

Alternatively, as illustrated inFIG. 16B, when the intermittent rotation of the toner bottle70stops, the stop phase of the conveying portion701is controlled so that the scooping portion701aenters a position of the upstream side (for example, approximately, −20° in the rotational direction slightly than the vertical direction. Thus, when the toner bottle rotates again, the quantity of toner scooped up by the scooping portion701aincreases compared to a case where the scooping portion701astops in the vertical direction, and even when the toner bottle stops, since the toner on the guide portion701bcan slide down, the discharge efficiency is satisfactory. However, in the case of the embodiment, since the guide portion701bis not in the vertical direction when stopping, the discharge efficiency when stopping is lower than the case of stopping in the vertical direction. However, since the quantity of scooping-up the toner increases accordingly, the toner discharge efficiency is satisfactory.

In addition, a unit configured to detect the phase of the conveying portion701needs not to be limited to the above-mentioned configuration, and other configurations may be adopted.

[Fourth Embodiment] In the first embodiment, the description has been given of a case where, when the residual quantity of toner in the toner bottle70decreases, by switching the toner bottle70from the continuous rotation to the intermittent rotation, it is possible to reduce the quantity of toner remaining in the toner bottle70. This is greatly influenced by the fact that the interval of the continuous scooping operation using the scooping portion701aof the toner conveying portion701becomes longer, and even in the continuous rotation, the rotation operation of the toner bottle70can slow down compared to a case where the quantity of toner in the toner bottle is large. Therefore, in the fourth embodiment, the case of performing the continuous constant speed rotation at a low speed when the residual quantity of toner in the toner bottle70is small will be described with reference toFIG. 17.

In the embodiment, when the quantity of toner in the toner bottle is large, the continuous rotation (rotational speed V1[rpm]) is performed. When the quantity of toner in the toner bottle decreases, even when the toner bottle continuously rotates at a rotational speed of V1for a predetermined time, since the presence of toner is not detected by the toner residual quantity detection portion401, it is determined that the residual quantity of toner is small, and the toner bottle70is switched to the low-speed continuous rotation (rotational speed V2[rpm]). In addition, there is a relation of V2<V1.

Discharging properties of the toner when continuously rotating the toner bottle at the rotational speed V2will be described with reference toFIGS. 9A and 9B. As the toner in the toner bottle, there is toner that is stirred and floats by the rotation of the toner bottle70and the conveying portion701. However, since the rotational speed V2is slower than the rotational speed V1, toner intensity being stirred within the toner bottle becomes weaker than the case of the rotational speed V1, and the toner floating in the toner bottle is reduced. As a result, the toner accumulated near the discharge opening portion increases compared to the case of the rotational speed V1, and the quantity of toner scooped up by the scooping portion701aincreases. Accordingly, the quantity of toner sliding down the guide portion701bincreases, and the quantity of discharge also increases. Furthermore, at the time of rotational speed V2, since the rotational speed is slower than the case of the rotational speed V1, the time when the toner is present in the region in which the toner can slide down the guide portion701bbecomes longer as compared to the case of the rotational speed V1. For this reason, even in the case where the quantity of toner scooped up by the scooping portion701ais equal to the case of the rotational speed V1, the quantity of discharge increases.

Even when the toner bottle is continuously rotated at V2for a predetermined time, if the presence of toner is not detected by the toner residual quantity detection portion401, the rotation of the toner bottle is stopped, and the replacement display of the toner bottle is performed.

FIG. 18is a flowchart illustrating the toner supply procedure of the embodiment. In the flowchart, the difference between the flowchart ofFIG. 18and the flowchart ofFIG. 12described in the first embodiment is step S404and step S407, and the others are identical. That is, in the embodiment, the toner bottle is continuously rotated at the rotational speed V1in a first supply mode in step S404, and the toner bottle is continuously rotated at a rotational speed V2in a second supply mode in step S407.

As described above, it is possible to obtain an effect similar to the embodiment described above, by continuously rotating the toner bottle70at the rotational speed V1in the first supply mode, and by continuously rotating the toner bottle70at the rotational speed V2slower than V1as the second supply mode when the residual quantity of toner is small. Moreover, in the embodiment, since the toner bottle is continuously rotated in both first supply mode and second supply mode, the drive control becomes easier than the case of the intermittent rotation.

[Fifth Embodiment] When the residual quantity of toner in the toner bottle decreases as in the above-mentioned embodiment, the reason for switching the toner bottle to the intermittent rotation is that the operation is influenced by the increase in the interval of the continuous scooping operation using the scooping portion of the toner conveying portion. The rotation operation of the toner bottle can be performed by the continuous shift rotation compared to a case where the quantity of toner in the toner bottle is large. In the fifth embodiment, the case of performing the continuous shift rotation when the residual quantity of toner in the toner bottle is small will be described with reference toFIG. 19.

When the quantity of toner in the toner bottle is large, the continuous rotation is performed (rotational speed V1). When the quantity of toner in the toner bottle decreases, even when the continuous rotation is performed at V1for a predetermined time, since the presence of toner is not detected by the toner residual quantity detection portion, it is determined that the residual quantity of toner is small, and the toner bottle is switched to the continuous shift rotation. Here, the continuous shift rotation means that the toner bottle periodically repeats the rotation of the rotational speeds V1and V2(<V1).

Moreover, in a case where the shortage of toner is continuously detected for a predetermined time, the rotation is stopped.

FIG. 20is a flowchart illustrating the toner supply procedure of the embodiment. In the flowchart, the difference between the flowchart ofFIG. 20and the flow chart ofFIG. 18described in the fourth embodiment is step S407, and the others are identical. That is, in the embodiment, the continuous rotation is performed in the first supply mode at the rotational speed V1as in the fourth embodiment, but the continuous shift rotation is performed in the second supply mode in step S407.

As described above, it is possible to obtain an effect similar to the embodiment described above, by continuously rotating the toner bottle70at the rotational speed V1in the first supply mode, and by performing the continuous shift rotation that continuously switches the rotational speeds V1and V2as the second supply mode when the residual quantity of toner is small.

[Sixth Embodiment] Next, a sixth embodiment will be described. The embodiment is characterized by a method of detecting the residual quantity of toner, when intermittently rotating the toner bottle as the second supply mode at the time of toner supply.

<Toner Residual Quantity Detection> In describing the embodiment, first, a process will be described in which the toner supplied to the toner accommodation portion302by the rotation of the toner bottle70is detected by the toner residual quantity detection portion401.

FIG. 21is a cross-sectional view of the toner replenishing apparatus301illustrating the flow of the toner supply. When the toner in the developing device4is consumed by copying, the print job and the like, and the toner in the developing device4is reduced, the toner conveying member305in the toner replenishing apparatus301rotates by the replenishment request signal, and the toner is replenished to the developing device4. The toner conveying member303is also operated at the same time as the rotation of the toner bottle70to convey the toner in the toner accommodation portion302in the direction of arrow A.

When the toner in the toner accommodation portion302is conveyed in the direction of arrow A, the height of the toner powder surface of the upstream side (portion of the vicinity of the toner residual quantity detection portion401) of the toner conveying member303is lowered, and the “shortage of toner” is detected by the toner residual quantity detection portion401. When the toner residual quantity detection portion401detects the “shortage of toner”, a toner bottle drive portion (not illustrated) is operated, and the toner bottle70rotates. When the toner bottle70rotates, the toner in the bottle is discharged from the toner discharge opening portion702, falls free, and is deposited in the toner accommodation portion302directly below the discharge opening portion702as described above.

The toner deposited in the toner accommodation portion302is conveyed in the direction of arrow A while the powder surface is leveled, by the toner conveying member303operating together with rotation of the toner bottle70. At the same time, the height of the toner powder surface in the toner accommodation portion302is detected by the toner residual quantity detection portion401, and when the height of the toner powder surface reaches a predetermined height, the “presence of toner” is detected to stop driving of the toner bottle70and the toner conveying member303. At this time, the “presence of toner” determination time using the toner residual quantity detection portion401is preferably set to be shorter in order to prevent the excessive replenishment of toner, and is approximately 100 ms in the embodiment.

By repeating the above operation, it is possible to substantially constantly maintain the density of toner in the toner accommodation portion302, and it is possible to quantitatively replenish the toner to the developing device4.

<Toner Residual Quantity Determination Time> Next, the toner discharge when the toner bottle70rotates intermittently, and the method of detecting the toner residual quantity detection portion401will be described with reference toFIGS. 22 to 25.FIG. 22is a cross-sectional view of the toner bottle70, andFIG. 23is a cross-sectional view of the toner replenishing apparatus301as viewed from the toner bottle70side.

In a case where the residual quantity of toner in the toner bottle70is lowered, the toner supply mode becomes the second supply mode, and the toner bottle70intermittently rotates, during the rotation of the toner bottle70, the toner is discharged from the discharge opening portion702of the toner bottle70as described above. At this time, when the toner bottle70rotates, as illustrated inFIG. 23, the discharged toner is deposited unevenly in the toner accommodation portion302, but the toner is conveyed by the toner conveying member303operating together with the toner bottle70, and toner powder surface is leveled. Thereafter, the height of the toner powder surface in the toner accommodation portion302is detected by the toner residual quantity detection portion401, and when the height of the toner powder surface reaches a predetermined height, the “presence of toner” is detected to stop driving of the toner bottle (not illustrated) and the toner conveying member303.

On the other hand, during stop of the toner bottle70, since the conveying portion701also stops, the toner of the bottom portion in the toner bottle70is not scooped up, but the toner deposited in the guide portion of the conveying portion701slides down the guide portion701band is discharged from the discharge opening portion702. That is, the toner is discharged even after the toner bottle70stops. That is, as illustrated inFIG. 24, the discharged toner is deposited unevenly in the toner accommodation portion302. However, since the toner bottle70stops, the toner conveying member303operating together with rotation of the toner bottle also stops, and the toner deposited unevenly in the toner accommodation portion302is held in that state.

In a case where the toner residual quantity detection portion401is an optical detection type, when the toner deposited unevenly shields a part of the light transmitting portion, even in a case where the quantity of toner in the toner accommodation portion302is small, the “presence of toner’ is detected. When the quantity of toner in the toner accommodation portion302decreases, the toner density in the toner accommodation portion302drops, the quantitative replenishment of the toner to the developing device4cannot be performed, and the ratio of the toner in the developing device4changes, which may lead to an image failure and an error.

Therefore, in the embodiment, as illustrated inFIG. 25, the “presence of toner” determination time t1using the toner residual quantity detection portion401is set to be longer than a stop time t2of the intermittent rotation of the toner bottle70(t1>t2). In this manner, since the toner conveying member303is necessarily operated during the “presence of toner” determination time and the toner powder surface deposited unevenly in the toner accommodation portion302is leveled, it is possible to detect the stable “presence of toner” by the toner residual quantity detection portion401.

In addition, in the embodiment, the stop time t2of the intermittent rotation of the toner bottle70is 1800 ms, whereas the “presence of toner” determination time t1using the toner residual quantity detection portion401is 2200 ms.

As described above, in a case where the toner bottle70is intermittently rotated, by setting the “presence of toner” determination time t1of the toner residual quantity detection portion to be longer than the stop time t2of the toner bottle intermittent rotation, it is possible to stabilize the quantity of toner in the toner accommodation portion. As a result, since the quantity of toner supplied to the developing device from the toner replenishing device is also stabilized, it is possible to prevent the occurrence of a defective image or an error.

In addition, in the embodiment, as a method of detecting the residual quantity of toner, the optical sensor type is described, but the same also applies to the case of detecting the height of the toner powder surface by a piezoelectric sensor type or the like.

In the embodiment, an example has been described in which the toner bottle70is continuously rotated at the time of the first mode as the normal replenishment operation (when the quantity of toner in the toner bottle is large), but the invention is not limited thereto. For example, a configuration that performs the intermittent replenishment even at the normal time may be adopted within the range in which the effects of the invention are obtained. In other words, as long as the second supply mode has the quantity of rotation per unit time less than the first supply mode, needless to say, a configuration may be adopted in which the intermittent driving is performed even in the drive conditions of the first supply mode. In this case, it is preferable to increase the frequency of stop during the intermittent driving in the second supply mode compared to the first supply mode in view of the discharge efficiency. Furthermore, needless to say, it may cope with the operation by changing the speed during rotation at the time of the intermittent driving the first and second modes. Furthermore, it may cope with the operation by shortening the drive ON time during the bottle intermittent operation. Of course, the configurations and the embodiments described above may be combined with one another without departing from the effects of the invention.

According to the invention, since there is a plurality of developer supply modes from the container main body, for example, when the quantity of developer in the container decreases, it is possible to efficiently move the developer in the container to the opening portion, by switching the mode to the second supply mode to reduce the quantity of rotation of the container per unit time. Thus, it is possible to reduce the quantity of developer remaining in the container, without incurring the costs.

This application claims the benefit of Japanese Patent Application No. 2012-202948, filed Sep. 14, 2012, and No. 2013-155213, filed Jul. 26, 2013, which are hereby incorporated by reference herein in their entirety.