JP2009069177A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which toner supply failure when replacing a toner cartridge with a new one is reduced without using a high torque motor. <P>SOLUTION: The image forming apparatus conveys toner by rotating a conveying screw 32 in a toner cartridge. The image forming apparatus includes a driving source 102 reversely rotatable; a first driving force transmitting section that transmits the driving force of the driving source 102 to the conveying screw 32; a second driving force transmitting section that transmits the driving force of the driving source 102 to the conveying screw 32 at torque higher than that used in the first driving force transmitting section; and a driving force transmission switching section that switches the rotating direction of the driving source 102, thereby switching the transmission of driving force from the driving source 102 to the first or second driving force transmitting section. When toner is conveyed to be supplied, the conveying screw 32 is rotated via the first driving force transmitting section. Alternatively, when at least the toner cartridge is replaced with a new one, the conveying screw 32 is rotated via the second driving force transmitting section. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that includes a toner cartridge and forms an image by electrophotography.

  In an electrophotographic system used for image formation by an image forming apparatus such as a copying machine or a printer, first, an electrostatic latent image is formed by subjecting a photosensitive member, which is an electrostatic latent image carrier, to exposure processing according to image information. Then, a developer for visualizing the formed electrostatic latent image (for example, negatively or positively charged toner) is attached and developed to obtain a visible image. The visible image is transferred from the latent image carrier to the paper directly or via an intermediate transfer member, and then fixed on the paper by heating or the like.

In such an image forming apparatus that forms an image using toner, when the toner stored in the apparatus is consumed and the toner in the toner supply container such as a toner cartridge is reduced, the toner cartridge is replaced with a new one. Image formation can be continued.
In the image forming apparatus, toner is supplied (supplemented) from the toner cartridge to the developing device by rotating a conveying screw provided in the toner cartridge, but the toner in the new toner cartridge is solidified. As a result, the movement of the conveying screw is hindered, and toner replenishment may not be possible. Therefore, when a new toner cartridge is mounted, the wearer performs a swinging operation immediately before the mounting so as to release the solidified toner.

In addition, the image forming apparatus disclosed in Patent Document 1 includes a motor that rotates the conveying screw in the toner cartridge in the forward and reverse directions. By rotating the screw in the reverse direction, the solidified toner inside the container of the toner cartridge is released.
JP 11-133744 A

  However, when the wearer swings the toner cartridge immediately before the new toner cartridge is mounted, the toner other than around the conveying screw provided in the toner cartridge is released, but the toner around the conveying screw is shaken. However, the conveying screw hinders the movement of the toner and cannot be solved sufficiently. For this reason, the conveying screw in the toner cartridge does not rotate with the normal driving torque (when the toner is replenished) due to the solidified toner around the conveying screw, and the toner may not be replenished when the toner cartridge is still replaced with a new one. . Further, as disclosed in Patent Document 1, it is disclosed that the conveying screw is rotated in the reverse direction. However, the drive torque for rotating the conveying screw in the reverse direction when the toner cartridge is replaced with a new toner cartridge is usually used. A torque higher than the torque at the time of conveyance is required, and this problem cannot be solved simply by reversing the rotation direction of the conveyance screw.

  To solve this problem, there is a method of increasing the torque of the drive motor that drives the conveying screw, but this method not only increases the size of the motor but also increases the power consumption, and further increases the power consumption. Various problems arise, such as the need to prepare a large-scale power supply capable of supplying power.

  The present invention has been made in consideration of the above-described circumstances, and an image forming apparatus capable of reducing defective toner replenishment at the time of replacement with a new toner cartridge without using a high torque motor. The purpose is to provide.

  In order to solve the above-described problem, a first technical means of the present invention is an image forming apparatus including a toner conveying unit that conveys toner by rotating a conveying screw in a mounted toner cartridge, the toner The transport unit includes a drive source capable of reversible rotation, a first drive force transmission unit that transmits the drive force of the drive source to the transport screw, and a torque higher than that of the first drive force transmission unit, A second driving force transmission unit that transmits the driving force of the driving source to the conveying screw, and a switching between the rotation directions of the driving source, the first driving force transmission unit and the second driving force transmission unit. A driving force transmission switching unit that switches transmission of driving force from the driving source, and when the toner is replenished and conveyed in image formation, the conveying screw is interposed via the first driving force transmission unit. Rotate Dynamic and, when at least the toner cartridge is replaced with new one, in which is characterized in that disintegrate rotationally driving the toner the transport screw through the second driving force transmission unit.

  According to a second technical means, in the first technical means, the toner cartridge includes a moving member that is moved by a driving force transmitted through the toner conveying portion, and the image forming apparatus includes A new / old determination unit that determines whether or not the toner cartridge is new based on a state is provided.

  According to a third technical means, in the first or second technical means, a wall surface facing the end of the transport screw in the toner storage portion of the toner cartridge is inclined in a direction opposite to the toner replenishment transport direction. It is characterized by forming.

  According to a fourth technical means, in any one of the first to third technical means, the toner cartridge includes an elastic member that rotates to move the toner to the conveying screw.

  According to a fifth technical means, in any one of the first to fourth technical means, the driving force transmission switching unit includes two one-way clutches, and one of the one-way clutches has one driving source. The other one-way clutch transmits a driving force when the drive source rotates in a direction opposite to the one direction.

  Sixth technical means includes any one of the first to fifth technical means in which the rotational driving is performed via the first driving force transmission unit and the second technical driving force transmission unit. In the case of driving, the rotation direction of the conveying screw is the same or the reverse direction.

  According to a seventh technical means, in any one of the first to sixth technical means, when the image forming operation has been stopped for a predetermined time or more, the second driving force is applied when the image forming apparatus is restarted. The conveying screw is rotationally driven through a transmission unit.

  In the present invention, when the toner cartridge is replaced with a new one, the rotation direction of the drive source is changed to a different one from the normal time, and the conveying screw is rotated at a high torque, so that the solidified toner around the conveying screw is released. Can do. Since the toner once released can be conveyed with a normal torque, the apparatus of the present invention can reduce toner replenishment failure when the toner cartridge is replaced.

The outline of the image forming apparatus according to the present invention will be described with reference to FIG. FIG. 1 is a diagram illustrating an example of a configuration of a digital color multifunction peripheral to which an image forming apparatus according to the present invention is applied.
A digital color multifunction peripheral (hereinafter referred to as a multifunction peripheral) 100 forms multi-color and single-color images on a predetermined sheet (recording paper) in accordance with image data of a read image or image data transmitted from the outside. The apparatus main body 110 and the automatic document processing apparatus 120 are configured.

The automatic document processor 120 automatically conveys a document onto a document placing table 92 at the top of the apparatus main body 110. Further, the automatic document processing device 120 is configured to be rotatable in the direction of arrow M, and the document can be manually placed by opening the document table 92.
The image data handled in the image forming apparatus includes data corresponding to a color image using each color of black (K), cyan (C), magenta (M), and yellow (Y). Accordingly, four development units 2, photosensitive drums 3, chargers 5, and cleaner units 4 are provided so as to form four types of latent images corresponding to the respective colors. Black, cyan, magenta, yellow Is set to

  The charger 5 is a charging unit for uniformly charging the surface of the photosensitive drum 3 to a predetermined potential. The exposure unit 1 exposes the photosensitive drum 3 uniformly charged by the charger 5 according to the input or read image data, so that the surface of the photosensitive drum 3 is statically matched to the image data. It has a function of forming an electrostatic latent image.

The developing unit 2 visualizes the electrostatic latent images formed on the respective photosensitive drums 3 with toner of four colors (YMCK), and the toner is supplied from the toner cartridge 30 as will be described later. It has become so.
The cleaner unit 4 removes and collects toner remaining on the surface of the photosensitive drum 3 after development and image transfer.

The intermediate transfer belt unit 6 disposed above the photoconductive drum 3 is provided with a toner image of each color formed on the photoconductive drum 3 on an intermediate transfer belt 61 provided so as to be in contact with the photoconductive drum 3. Are sequentially superimposed and transferred to form a color toner image (multicolor toner image).
The transfer of the toner image from the photosensitive drum 3 to the intermediate transfer belt 61 is performed by an intermediate transfer roller 62 that is in contact with the back side of the intermediate transfer belt 61. A high-voltage transfer bias (a high voltage having a polarity (+) opposite to the toner charging polarity (−)) is applied to the intermediate transfer roller 62 in order to transfer the toner image.

  As described above, the electrostatic images visualized according to the respective hues on the respective photosensitive drums 3 are laminated on the intermediate transfer belt 61. The laminated image information is transferred onto the sheet by the transfer roller 10 disposed at a contact position between the sheet and the intermediate transfer belt 61 described later by the rotation of the intermediate transfer belt 61. At this time, the intermediate transfer belt 61 and the transfer roller 10 are pressed against each other at a predetermined nip, and a voltage for transferring the toner onto the sheet is applied to the transfer roller 10 (the polarity opposite to the toner charging polarity (−)). (+) High voltage).

  Further, as described above, the toner attached to the intermediate transfer belt 61 by contacting the photosensitive drum 3 or the toner that is not transferred onto the sheet by the transfer roller 10 and remains on the intermediate transfer belt 61 is processed in the next step. Therefore, the intermediate transfer belt cleaning unit 63 is configured to remove and collect the toner.

  The paper feed cassette 81 is a tray for storing sheets (recording paper) used for image formation, and is provided below the exposure unit 1 of the apparatus main body 110. In addition, a sheet used for image formation can be placed in the manual paper feed cassette 82. A paper discharge tray 91 provided above the apparatus main body 110 is a tray for collecting printed sheets face down.

  Further, the apparatus main body 110 has a substantially vertical sheet conveyance path S for feeding the sheets of the sheet feeding cassette 81 and the manual sheet feeding cassette 82 to the sheet discharge tray 91 via the transfer roller 10 and the fixing unit 7. Is provided. In the vicinity of the paper transport path S from the paper feed cassette 81 or the manual paper feed cassette 82 to the paper discharge tray 91, a pickup roller 11, a plurality of transport rollers 12, a registration roller 13, a transfer roller 10, a fixing unit 7, and the like are arranged. Has been.

The conveyance rollers 12 are small rollers for promoting and assisting the conveyance of the sheet, and a plurality of conveyance rollers 12 are provided along the sheet conveyance path S. The pickup roller 11 is provided in the vicinity of the end of the paper feed cassette 81 or the manual paper feed cassette 82, picks up sheets one by one from the paper feed cassette 81 or the manual paper feed cassette 82, and supplies them to the paper transport path S. To do.
Further, the registration roller 13 temporarily holds the paper being conveyed through the paper conveyance path S. The sheet has a function of conveying the sheet to the transfer roller 10 at the timing when the leading edge of the toner image on the photosensitive drum 3 is aligned with the leading edge of the sheet.

  The fixing unit 7 has a function of fusing, mixing, and pressing the multicolor toner image transferred to the paper, and thermally fixing the paper to the paper by thermally pressing the toner onto the paper with the heat roller 71 and the pressure roller 72. Have. The paper on which the unfixed toner is melted and fixed by heat by passing through the fixing unit 7 is discharged onto the paper discharge tray 91 via the transport roller 12 disposed in the paper transport path S on the downstream side, for example. .

  The image forming apparatus of the present invention is provided with a toner transport unit that transports toner to the developing unit 2 by rotating a transport screw, which will be described later, in the toner cartridge 30, and transports the toner cartridge 30 when it is replaced with a new toner cartridge. The solidified toner in the toner cartridge 30 can be released by switching the rotation direction of the driving source that generates the driving force for driving the screw.

  A toner replenishing mechanism for replenishing the drive unit with toner for visualizing the electrostatic latent image formed on the photosensitive drum will be described with reference to FIGS. FIG. 2 is a cross-sectional view showing a simplified configuration of the toner replenishing mechanism of the multifunction peripheral 100 of FIG. 3 is a cross-sectional view of the toner replenishing mechanism in the multifunction peripheral 100 of FIG. 1 as viewed from the direction A in FIG. 2, and FIGS. 3 (A) and 3 (B) show the toner cartridge 30 in the multifunction peripheral 100. The state before attachment and after attachment is shown in a simplified manner.

  In the image forming apparatus of the example of FIG. 1, that is, the multifunction peripheral 100, the development unit 2 for each color of black (K), cyan (C), magenta (M), and yellow (Y) is a two-component development that includes toner and a carrier. The electrostatic latent image formed on the photosensitive drum 3 is developed using an agent to make a visible image. As shown in FIG. 2, the toner cartridge 30 for each color passes through a toner dropping pipe 21a. Toner can be replenished. Since each toner replenishing mechanism for supplying toner to the developing unit 2 for each color has the same configuration, hereinafter, it will not be described as “developing unit for black” or the like. The description will be collectively given with the abbreviations such as “development unit” and “toner cartridge” omitted.

The developing unit 2 constituting the toner supply mechanism includes a developer container 21, a developing roller 22, a regulating member 23, a stirring roller 24, and a toner concentration sensor 25.
The developer container 21 contains a developer including toner and a carrier, and a toner dropping pipe 21a is provided on one upper side so as to be connected to the toner cartridge 30, and on the side opposite to the toner dropping pipe 21a. A developing chamber 21b is provided. An opening 21c is formed in the upper part of the developing chamber 21b. The developing roller 22 holds and conveys the developer, and is rotatably provided in the developer container 21. By rotating, the developing roller 22 passes through the opening 21c of the developer container 21 (FIG. 1). Developer) can be supplied.

  The regulating member 23 regulates the layer thickness of the developer on the surface of the developing roller 22. The agitation roller 24 is rotatably provided in the developer container 21, and can rotate and agitate the developer to charge the toner by rotating. In the example of FIG. 2, two agitation rollers 24 are provided to convey toner in opposite directions, one of which is provided in the developing chamber 21b. The toner concentration sensor 25 detects the toner concentration of the developer contained in the developer container 21 and is located below the developing chamber 21b of the developer container 21 and opposed to the stirring roller 24 on the developing roller 22 side. Is provided.

  A toner cartridge 30 for replenishing toner to the developing unit 2 is detachably attached to the multi-function device 100 of FIG. 1, and includes a toner container 31, a conveying screw 32, a toner agitating / conveying unit 33, and the like. ,including. The toner container 31 is a toner storage portion for storing toner, and has a toner drop port 31a connected to the toner drop pipe 21a of the developing unit 2 formed at the bottom as will be described later. The conveying screw 32 is rotatably provided in the toner container 31 and can convey toner by rotating via a drive motor described later. The toner agitating / conveying unit 33 agitates the toner in the toner container 31 and can further move the toner in the direction of the conveying screw 32.

  In the toner container 31, the conveying screw 32 is provided at one bottom, and the toner agitation-conveying unit 33 is provided on the opposite side to the conveying screw 32 side. Further, the conveying screw 32 rotates to convey the toner in the toner container 31 toward the toner dropping port 31a (that is, toward the developing unit 2). In this specification, the direction of rotation at this time Is the forward direction, and the direction of rotation in which the toner is conveyed in the direction away from the toner drop port 31a is the reverse direction.

  The toner agitating / conveying unit 33 includes an elastic sheet rotating shaft 33a rotatably provided in the toner container 31 and an elastic sheet 33b attached to the elastic sheet rotating shaft 33a. When the conveying screw 32 rotates in the forward direction, the elastic sheet 33b rotates around the inner wall surface at the bottom of the toner container 31 about the elastic sheet rotation shaft 33a. For this reason, since the toner at the bottom of the toner container 31 on the toner stirring-conveying unit 33 side can be supplied to the conveying screw 32 so as to be scraped off, the toner can be used without waste.

  In the image forming apparatus including the developing unit 2 and the toner cartridge 30 as described above, the conveying screw 32 in the toner cartridge 30 is driven to rotate according to the detection result by the toner density sensor 25, and the toner dropping pipe is removed from the toner container 31. Toner is supplied to the developer container 21 through 21a. The toner replenished to the developer container 21 is stirred and charged by the stirring roller 24 and is conveyed to the developing chamber 21b. The carrier (developer) carrying toner in the developing chamber 21 b is held and conveyed by the developing roller 22 and is regulated to an appropriate layer thickness by the regulating member 23. When the developer thin layer formed on the developing roller 22 is conveyed to the opening 21c of the developer container 21 by the rotation of the developing roller 22, the toner in the developer is static on the photosensitive drum 3 (see FIG. 1). The toner image is formed by shifting to the electrostatic latent image.

  Further, in the image forming apparatus, as shown in FIG. 3A, an apparatus side coupling 101 is rotatably provided to drive the conveying screw 32 of the toner cartridge 30. The apparatus-side coupling 101 is for transmitting power from a drive motor that can be driven in both forward and reverse directions to the conveying screw 32. In the toner cartridge 30, a cartridge side coupling 34 that receives power from the apparatus side coupling 101 is provided to be rotatable with respect to the toner container 31. The cartridge side coupling 34 is provided outside the toner container 31, and transmits the power from the drive motor received via the apparatus side coupling 101 to the conveying screw 32 in the toner container 31.

  For example, the apparatus-side coupling 101 is formed with a protrusion 101a extending in the attaching direction and the detaching direction (detaching direction) of the toner cartridge, and the protrusion 101a is inserted into and engaged with the end of the cartridge-side coupling 34. A recess 34a is formed. The toner cartridge 30 is attached to, for example, the toner cartridge housing portion of the multifunction peripheral 100 of FIG. 1 so that the protrusion 101a of the apparatus side coupling 101 is inserted into the recess 34a of the cartridge side coupling 34. Due to the engagement between the protrusions 101a and the recesses 34a, the conveying screw 32 of the toner cartridge 30 can be driven when the drive motor operates.

  In the toner cartridge 30, a toner agitation / conveyance unit 33 and a transmission gear 35 for driving a moving member to be described later are fixed to the cartridge side coupling 34 side of the conveyance screw 32. The transmission gear 35 is provided inside the toner container 31 so as to be rotatable with respect to the toner container 31 together with the cartridge side coupling 34 and the conveying screw 32.

  Further, the toner cartridge 30 is provided with an opening 31a for supplying toner to the toner dropping pipe 21a at the bottom on the cartridge side coupling 34 side, and an inclined surface 31b is formed on the opposite side of the opening 31a. . The opening 31a is connected to the toner dropping pipe 21a of the developing unit 2 as shown in FIG. 3B when the toner cartridge 30 is attached to the apparatus and the cartridge side coupling 34 and the apparatus side coupling 101 are engaged. Is done.

  When the conveying screw 32 of the toner cartridge 30 attached to the apparatus is rotated in the forward direction and the toner is conveyed in the direction of the opening 31a, the toner falls to the developing unit 2 via the toner dropping pipe 21a. Further, even if the conveying screw 32 is rotated in the opposite direction and the toner is conveyed in the direction opposite to the direction toward the opening 31a, the end in the conveying direction in this case is the inclined surface 31b, so that the toner is compressed and solidified. Never happen.

  In an example of the image forming apparatus according to the present invention, as will be described later, when the toner cartridge 30 is new when the toner cartridge 30 is attached, the conveyance screw 32 is reversely rotated at a low speed and a high torque, thereby the conveyance screw 32. The toner adhering to the periphery of the toner is released and conveyed toward the inclined surface 31b. The toner on the inclined surface 31b is pushed out along the inclined surface 31b (for example, upward) in the toner cartridge 30. Since the extruded toner falls around the conveying screw 32, it can be understood even if it is solidified in a block shape.

In the image forming apparatus of the present invention, when the toner cartridge is new, the motor for driving the conveying screw 32 of the toner conveying unit is rotated in the direction opposite to that during normal toner replenishment to drive the conveying screw constituting the toner conveying unit. The mechanism is characterized in that the toner is released by switching the mechanism to a different one from that during normal toner replenishment and rotationally driving the conveying screw 32 with high torque.
Therefore, the conveying screw driving mechanism will be described with reference to FIGS. FIG. 4 is a schematic view for explaining a conveying screw driving mechanism configured in the image forming apparatus of the present invention. FIGS. 5A and 5B are schematic diagrams for explaining the operation of the conveying screw drive mechanism on the apparatus side. FIGS. 5A and 5B show the operation of the conveying screw drive mechanism during normal toner replenishment and high torque application, respectively. It is for explaining.

In this image forming apparatus, as shown in FIG. 4, the conveying screw 32 is connected to a driving motor (driving source) 102 that can be rotated reversibly via the apparatus side coupling 101 and the like, and is controlled and driven by a control means (not shown). Is done.
During normal toner replenishment, the conveying screw 32 is driven to rotate clockwise as viewed from above in the figure by the driving motor 102, and conveys toner in the direction of the opening (toner dropping port) 31a. On the other hand, when the toner cartridge is new, the conveying screw 32 is driven to rotate at a higher torque, for example, counterclockwise, for example, when toner is replenished.
The drive motor 102 is composed of, for example, a stepping motor, and a transmission gear G1 is fixed to the output shaft thereof. The transmission gears G2 and G6 mesh with the transmission gear G1, respectively.

The transmission gear G2 is provided on the support shaft P1 via the first one-way clutch C1. The first one-way clutch C1 is driven clockwise while the drive motor 102 is driven counterclockwise as viewed from above and the transmission gear G2 is driven clockwise, while the spindle P1 is driven clockwise. When the drive motor 102 is driven and the transmission gear G2 is driven counterclockwise, the support shaft P1 is not driven. In addition, when demonstrating regarding a rotation direction below, it demonstrates as what was seen from the upper part of the figure.
A transmission gear G3 is fixed to the support shaft P1, and a transmission gear G4 that meshes with the transmission gear G3 is fixed to the support shaft P2. The transmission gear G4 meshes with a transmission gear G5 that is fixed to the other end of the support shaft P3 provided with the apparatus-side coupling 101 at one end.

  The transmission gear G6 is provided on the support shaft P4 via the second one-way clutch C2. The second one-way clutch C2 drives the support shaft P4 when the drive motor 102 is driven clockwise and the transmission gear G6 is driven counterclockwise, while the drive motor 102 is driven counterclockwise. When driven and the transmission gear G6 is driven clockwise, the support shaft P4 is not driven. The second one-way clutch C2 has the same size and shape as the first one-way clutch C1 except for the rotation transmission direction.

  A transmission gear G7 is fixed to the support shaft P4, and a transmission gear G8 that meshes with the transmission gear G7 and has more teeth than the transmission gear G4 is fixed to the support shaft P5. The transmission gears G6 and G7 have the same shape as the transmission gears G2 and G3, respectively. In addition to the transmission gear G8, a transmission gear G9 is fixed to the support shaft P5. The transmission gear G9 has a smaller diameter than the transmission gear G8, and has the same shape as the transmission gear G4, for example. The transmission gear G9 meshes with the transmission gear G5.

  Further, the support shafts P1 to P5 to which various transmission gears are fixed are pivotally supported by the apparatus frame via bearing members (not shown).

In such a conveying screw drive mechanism, during normal toner replenishment, as shown in FIG. 5A, the transmission gear G1 of the drive motor 102 is rotated in the counterclockwise direction (first direction) indicated by the solid line. Rotate. At this time, since the transmission gear G1 fixed to the output shaft of the drive motor 102 rotates counterclockwise, the transmission gear G2 rotates clockwise. Therefore, the transmission gear G3 is connected to the first one-way clutch C1. Through the transmission gear G2 and rotate clockwise. The transmission gear G4 rotates counterclockwise by the transmission gear G3, and the transmission gear G5 rotates clockwise by the transmission gear G4.
As a result, the conveying screw 32 (see FIG. 4) rotates in the positive direction by the clockwise driving force transmitted from the driving motor 102, and conveys the toner in the toner cartridge 30 toward the toner dropping port 31a. The developing unit 2 can be replenished with toner.

  Further, in the above conveying screw drive mechanism, when the attached toner cartridge 30 is new, the transmission gear G1 of the drive motor 102 has, for example, the same driving force and rotational speed as that during normal toner replenishment. As shown in FIG. 5B, the motor rotates in a clockwise direction (second direction) indicated by a broken line. At this time, since the transmission gear G1 of the output shaft of the drive motor 102 rotates clockwise, the transmission gear G6 rotates counterclockwise, so that the transmission gear G7 is connected via the second one-way clutch C2. It rotates counterclockwise following the transmission gear G7. By this transmission gear G7, the transmission gear G8 rotates clockwise.

  At this time, the transmission gear G6, the second one-way clutch C2, and the transmission gear G7 have the same shape as the transmission gear G2, the first one-way clutch C1, and the transmission gear G3. A force having the same magnitude as that applied to the transmission gear G4 during normal toner conveyance is applied. At this time, since the number of teeth of the transmission gear G8 is larger than that of the transmission gear G4, the transmission gear G8 rotates at a rotational angular velocity smaller than the rotational angular velocity of the transmission gear G4 during normal toner conveyance.

Then, the transmission gear G9 having a smaller diameter than the transmission gear G8 and the same number of teeth as the transmission gear G4 follows the transmission gear G8 and rotates clockwise, so that the transmission gear G5 engaged with the transmission gear G9 rotates counterclockwise. .
As a result, the conveying screw 32 (see FIG. 4) rotates in the reverse direction at a higher torque and at a lower speed than the normal toner replenishment due to the counterclockwise driving force transmitted from the driving motor 102. 30 toner can be removed.

  The image forming apparatus includes a first driving force transmission unit (first transmission unit) that transmits a driving force to the conveying screw 32 so that the conveying screw 32 is driven at a torque and a rotation speed at the time of normal toner replenishment. A second driving force transmission unit (second transmission unit) that transmits a driving force to the conveying screw 32 so that the conveying screw 32 is driven at a torque larger than the torque at the time of toner replenishment and at a lower rotational speed. Prepare. In the above-described example, the first driving force transmission unit includes the transmission gears G4 and G5, the support shafts P2 and P3, and the apparatus side and cartridge side couplings 101 and 34. The second driving force transmission unit includes transmission gears G8, G9, G5, support shafts P5, P3, and apparatus side and cartridge side couplings 101, 34.

  The image forming apparatus determines whether the driving force from the driving motor is transmitted to the first driving force transmission unit or the second driving force transmission unit by switching the rotation direction of the driving motor. A driving force transmission switching unit for switching is provided. In the above-described example, the driving force transmission switching unit includes the transmission gears G2, G3, G6, G7, the support shafts P1, P4, and the first and second one-way clutches C1, C2. The driving force transmission switching unit thus includes two one-way clutches. In the driving force transmission switching unit, the first one-way clutch C1 transmits driving force when the driving motor 102 rotates counterclockwise, and the second one-way clutch when the driving motor 102 rotates clockwise. C2 transmits the driving force. Thereby, the driving force transmission switching unit can switch between the first driving force transmission unit and the second driving force transmission unit according to the rotation direction of the driving motor 102.

According to the image forming apparatus of the present invention, the switching in the driving force transmission unit is performed by switching the rotation direction of the driving motor 102 according to the determination result in the old / new determination unit that determines whether or not the toner cartridge is new. If the toner is new, the toner conveying unit is driven at low speed and high torque.
Whether or not the toner cartridge is new is determined based on, for example, a user input to a display unit (not shown) when the image forming apparatus is configured as the multifunction peripheral 100 of FIG. Or can be performed based on whether the cover (door) of the storage portion of the container is opened or closed.

  As described above, when it is determined whether or not the toner cartridge is a new toner cartridge, it may not be correctly determined when the user makes an incorrect input or reinstalls the same toner cartridge. Therefore, in this image forming apparatus, it is possible to determine whether or not it is a new toner cartridge as follows.

  A new toner cartridge determination structure in the image forming apparatus will be described with reference to FIGS. FIG. 6 is a diagram illustrating the inside of the toner cartridge. FIG. 7 is a diagram for explaining a new / old detection switch provided in the image forming apparatus and a moving member provided in the toner cartridge for pressing the new / old detection switch. FIGS. 7A and 7B respectively show a state where the new / old detection switch is not pressed and a state where it is pressed.

  The toner cartridge 30 includes a moving member 36 that can press a new / old detection switch described later by moving in a direction in which the conveying screw 32 extends. The moving member 36 moves so as to press the new / old detection switch when the conveying screw 32 rotates in the reverse direction at a low speed and a high torque.

  As described above, the transmission gear 35 is fixed to the conveying screw 32 together with the cartridge side coupling. The transmission gear 35 meshes with a transmission gear G10 fixed to a support shaft (not shown), and the transmission gear G10 meshes with a transmission gear G11 fixed to a support shaft (not shown). The support shaft on which the transmission gears G10 and G11 are fixed is rotatably supported by the toner cartridge 30. The transmission gear G11 meshes with the transmission gear G12 fixed to the elastic sheet rotating shaft 33a to which the elastic sheet 33b is attached, and meshes with the transmission gear G13 fixed to the moving member 36. The moving member 36 has a thread on its shaft, and the thread is screwed into a part of the housing of the toner cartridge 30. With this thread, the moving member 36 protrudes from the toner cartridge when rotated clockwise. The transmission gears 35, G10 to G13 are provided inside the toner container 31 (see FIG. 2) of the toner cartridge 30.

  The new / old determination unit of the image forming apparatus determines whether the toner cartridge 30 is new or old depending on whether the new / old detection switch is pressed by the moving member 36.

  As shown in FIG. 7A, when the moving member 36 is not pressing the new / old detection switch 36 provided in the image forming apparatus, the new / old determination unit determines that the toner cartridge 30 is new. At this time, in order to release the solidified toner, the rotation direction of the drive source is selected (switched) so that the conveying screw 32 rotates in the reverse direction at low speed and high torque, and the cartridge side coupling 34 (see FIG. 6) is rotated counterclockwise. Along with this, the transmission gear 35 rotates counterclockwise. Then, the transmission gear G10 rotates clockwise, the transmission gear G11 rotates counterclockwise, and the transmission gear G13, that is, the moving member 36 rotates clockwise. As a result, the moving member 36 in the initial state (new state) rotates the screw and moves upward in the drawing, and as shown in FIG. 7B, pushes the new / old detection switch 103 attached to the apparatus main body. It becomes a state (old product state).

By pressing the new / old detection switch 103, the toner cartridge 30 is in a state of indicating an old product.
The moving member 36 once moved to the position of the old product does not return to the new position again by the elastic force of the elastic member (spring) 37. Further, the thread of the moving member 36 is formed only halfway along the shaft, and in the state of moving to the old product state, the moving member 36 has moved to a region where the thread of the moving member 36 is not formed. Even if the 36 transmission gear G11 rotates, it does not move in the axial direction.

  As a result, when the conveying screw 32 (see FIG. 6) rotates in the forward direction, the transmission gear G11 rotates clockwise, and the transmission gear G12 rotates counterclockwise, that is, the toner stirring-conveying unit 33. This prevents the elastic sheet 33b (see FIG. 6) from being hindered from moving the toner in the direction of the conveying screw.

  A toner supply process in the image forming apparatus will be described with reference to FIGS. 8 and 9 and FIG. FIG. 8 is a block diagram of a configuration example of the image forming apparatus of the present invention. FIG. 9 is a flowchart for explaining processing when the toner cartridge is replaced in the image forming apparatus.

  The image forming apparatus is configured as, for example, the multifunction machine shown in FIG. 1. As shown in FIG. 8, the new / old detection switch 103 for determining whether the toner cartridge 30 is new or old is set to Y, M, C, Prepare for each K color. Further, the image forming apparatus includes a toner concentration sensor 25 as a toner concentration detecting unit that detects the toner concentration in the developing chamber 21b of the developing unit 2 for each color, and the toner in the toner cartridge 30 is supplied to the developing unit 2. A drive motor (toner supply motor) 102 is provided as a drive source for driving the conveying screw 32 for supply.

  The image forming apparatus includes a control unit 104 for controlling processing in the image forming apparatus. The control unit 104 controls the drive motor based on the detection results of the toner density sensor and the old / new detection switch, and particularly constitutes the new / old determination unit together with the new / old detection switch. The control unit 104 is, for example, a ROM that stores a microcomputer and a control program that is a procedure of processing executed by the microcomputer, a RAM that provides a work area for work, and a non-volatile that backs up and holds data necessary for control. Memory, input signals from sensors and switches, connected to input circuits including input buffers and A / D conversion circuits, output circuits including drivers for driving loads such as motors, solenoids and lamps .

  When the image forming apparatus detects that the front cover (not shown) covering the inside of the apparatus has been opened and closed by an opening / closing detection switch (not shown), the image forming apparatus starts processing based on the flow of FIG. When the front cover that has been opened is closed and the toner cartridge 30 is set, the control unit 104 of the image forming apparatus determines whether the new / old detection switch 103 is on or off (whether or not it is pressed). It is determined whether or not the set toner cartridge 30 is new (step S1). If the old / new detection switch 103 is off, that is, if it is a new toner cartridge (step S1, YES), the toner supply motor 102 is rotated in the second direction (clockwise) for a certain period of time, and the conveying screw 32 is driven at low speed and high torque. The toner is removed by driving in the reverse direction (step S3).

  Next, the output of the toner density sensor 25 is confirmed (step S2). If the toner density is lower than a predetermined value (step S2, YES), the toner replenishment motor 102 is rotated in the first direction (counterclockwise) for a predetermined time. The toner is supplied to the developing unit 2 by driving the conveying screw 32 in the forward direction (step S4). This is repeated until the toner concentration becomes higher than a predetermined value. When it is determined in step S2 that the toner concentration is higher than the predetermined value (NO), the replenishment operation is stopped.

  If the set toner cartridge 30 is not new (in the case of step S1, NO), the process proceeds to step 2 and the replenishment operation is performed until the toner density becomes higher than a predetermined value.

  The control unit 104 measures the stop time of the image forming operation with a timer (not shown), and when the stop is longer than the stop time, controls the toner supply motor 102 to rotate in the second direction, thereby controlling the above-described second. You may control to drive the conveyance screw 32 via the driving force transmission part. In this case, the timer may be reset when the image forming operation is started, and the control unit 104 may detect the total stop time, and may be controlled to drive when the total time exceeds a predetermined time. Since the timer keeps counting for the time when the image forming apparatus is stopped, it is only necessary to determine the count time of the timer. By controlling in this way, it is possible to prevent the toner from solidifying again when a state in which no image forming operation is continued for a long time, resulting in a toner conveyance failure.

In the above example, when the toner cartridge is replaced with a new toner cartridge, the conveying screw 32 is rotated in the reverse direction. However, the image forming apparatus is configured to include the following rotation direction conversion unit, and the new one is replaced. Even if it is exchanged, the conveying screw 32 may be rotated in the forward direction.
FIG. 10 is a diagram for explaining a rotation direction conversion unit for rotating the conveying screw 32 in the forward direction when the toner cartridge is replaced with a new toner cartridge. Components similar to those in FIGS. 4 and 5 are denoted by the same reference numerals and description thereof is omitted.

The rotation direction conversion unit is for converting the rotation direction of the toner transport unit, and corresponds to the transmission gear G14 in the example of FIG. The transmission gear G14 meshes with the transmission gears G9 and G5 and is fixed to the support shaft P6. The support shaft P6 is provided to be rotatable with respect to the image forming apparatus.
Thereby, even if the drive source rotates clockwise (second direction) in order to drive the conveying screw 32 at low speed and high torque, the transmission gear G14 rotates counterclockwise by the transmission gear G9 rotating clockwise. Since the transmission gear G5 rotates clockwise by the transmission gear G14, the rotation direction of the conveying screw 32 is when the drive source rotates counterclockwise (first direction). Can be in the same direction of rotation. Thus, the toner replenishing operation can be performed while releasing the toner. That is, the toner replenishment time can be shortened by increasing one gear.

1 is a diagram illustrating an example of a configuration of a digital color multifunction peripheral to which an image forming apparatus according to the present invention is applied. FIG. 2 is a cross-sectional view showing a simplified configuration of a toner replenishment mechanism of the multifunction peripheral 100 of FIG. 1. FIG. 3 is a cross-sectional view of the toner replenishing mechanism in the multifunction peripheral 100 of FIG. 1 as viewed from the direction A of FIG. 2. It is the schematic for demonstrating the conveyance screw drive mechanism comprised in the image forming apparatus of this invention. FIG. 6 is a schematic diagram for explaining the operation of the conveying screw driving mechanism configured in the image forming apparatus of the present invention on the apparatus side. FIG. 3 is a schematic diagram illustrating the inside of a toner cartridge. It is the schematic for demonstrating an old and new detection switch and a moving member. 1 is a block diagram of a configuration example of an image forming apparatus of the present invention. 6 is a flowchart for explaining processing when a toner cartridge is replaced in the image forming apparatus of the present invention. FIG. 6 is a diagram for explaining a rotation direction conversion unit for rotating a conveying screw in a forward direction when the toner cartridge is replaced with a new toner cartridge.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Exposure unit, 3 ... Photosensitive drum, 4 ... Cleaner unit, 5 ... Charger, 6 ... Intermediate transfer belt unit, 7 ... Fixing unit, 21 ... Developer container, 21a ... Toner dropping pipe, 21b ... Developer chamber, 21c ... Opening, 22 ... Developing roller, 23 ... Regulating member, 24 ... Agitating roller, 25 ... Toner density sensor, 30 ... Toner cartridge, 31 ... Toner container, 31a ... Toner drop port (opening), 31b ... Inclined surface, 32 DESCRIPTION OF SYMBOLS ... Conveyance screw, 33 ... Conveyance unit, 33a ... Elastic sheet rotating shaft, 33b ... Elastic sheet, 34 ... Cartridge side coupling, 34a ... Concavity, 35 ... Transmission gear, 36 ... Moving member, 100 ... Multifunction machine, 101 ... Apparatus Side coupling, 101a ... protrusion, 102 ... drive motor (toner supply motor), 103 ... new / old detection switch, 104 ... control unit, 10 ... apparatus body 120 ... automatic document processor, C1 ... first one-way clutch, C2 ... second one-way clutch, G1～G14 ... transmission gear, P1 to P5 ... support shaft.

Claims (7)

An image forming apparatus including a toner transport unit that transports toner by rotating a transport screw in a mounted toner cartridge,
The toner conveying section is
A driving source capable of reversible rotation;
A first driving force transmission unit that transmits the driving force of the driving source to the conveying screw;
A second driving force transmission unit that transmits a driving force of the driving source to the conveying screw at a torque higher than the torque generated by the first driving force transmission unit;
A driving force transmission switching unit that switches transmission of driving force from the driving source to either the first driving force transmission unit or the second driving force transmission unit by switching the rotation direction of the driving source; With
When the toner is replenished and transported in image formation, the transport screw is rotationally driven via the first driving force transmission unit, and at least when the toner cartridge is replaced with a new one, the second drive is performed. An image forming apparatus, wherein the conveying screw is rotationally driven via a force transmission unit to release toner. The toner cartridge has a moving member that moves by a driving force transmitted through the toner conveying portion;
The image forming apparatus according to claim 1, further comprising a new / old determining unit configured to determine whether the toner cartridge is new based on a state of the moving member.   The wall surface of the toner storage portion of the toner cartridge facing the end portion of the conveying screw forms an inclined surface in a direction opposite to the toner replenishing and conveying direction. Image forming apparatus.   The image forming apparatus according to claim 1, wherein the toner cartridge includes an elastic member that rotates to move the toner to the conveying screw.   The driving force transmission switching unit includes two one-way clutches, one of the one-way clutches when the drive source rotates in one direction, and the other one-way clutch includes the drive source. The image forming apparatus according to claim 1, wherein a driving force is transmitted when the lens rotates in a direction opposite to the one direction.   The rotational direction of the conveying screw is the same or opposite in the case of rotational driving through the first driving force transmission unit and the case of rotational driving through the second driving force transmission unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   2. The image forming apparatus according to claim 1, wherein when the image forming operation has been stopped for a predetermined time or more, the conveying screw is rotationally driven via the second driving force transmission unit when the image forming apparatus is restarted. The image forming apparatus according to claim 6.

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