JP7807347B2 - Driving force transmission mechanism and image forming apparatus - Google Patents

Description

This invention relates to a drive force transmission mechanism and an image forming apparatus, and in particular to a drive force transmission mechanism and an image forming apparatus equipped with the same, which includes a drive force transmission device that transmits drive force from a motor to a driven member.

An example of a conventional image forming device equipped with this type of drive force transmission mechanism is disclosed in Patent Document 1. The image forming device in Patent Document 1 includes a cartridge storage unit installed in the device body, a toner cartridge configured to be insertable and removable into the cartridge storage unit, and a drive unit (drive force transmission mechanism) installed in the device body and configured to be attachable and detachable to the toner cartridge. This drive unit includes a motor, a drive transmission member (drive-side rotating member), an eject cam (driven-side rotating member), an eject arm (driven member), and an arm position detection sensor (displacement detection sensor), among other components.

JP 2016-109712 A

In the technology of Patent Document 1, a one-way clutch is connected to the shaft of the eject cam, and when the drive transmission member rotates in a predetermined direction, the rotational force is transmitted to the eject cam. Patent Document 1 does not disclose the specific configuration of the one-way clutch, but it is desirable for a drive force transmission device with one-way clutch functionality to be compact. It is also desirable for the drive force to be transmitted reliably even if there are manufacturing errors in the components.

Therefore, the primary objective of this disclosure is to provide a novel drive force transmission mechanism and image forming apparatus.

Another object of this disclosure is to provide a drive force transmission mechanism and an image forming apparatus that can be miniaturized and can reliably transmit drive force even if there are manufacturing errors.

The first disclosure is a driving force transmission mechanism that includes a driving force transmission device that transmits driving force from a motor to a driven member. The driving force transmission device includes a support shaft, a driving-side rotating member that has a first cylindrical portion through which the support shaft is inserted and is rotatably attached to the support shaft, a driven-side rotating member that has a second cylindrical portion through which the support shaft is inserted and is rotatably attached to the support shaft adjacent to the driving-side rotating member and transmits driving force to the driven member, and a coil spring into which the first cylindrical portion is press-fitted at one end and the second cylindrical portion is press-fitted at the other end, which transmits the driving force of the driving-side rotating member to the driven-side rotating member when the driving-side rotating member is rotated in a first direction. The driving force transmission mechanism also includes a motor that rotates the driving-side rotating member, and a motor control unit that controls the operation of the motor. The motor control unit controls the motor to gradually increase the rotational speed of the driving-side rotating member when transmitting driving force from the driven-side rotating member to the driven member.

According to the first disclosure, the use of a coil spring one-way clutch allows for the miniaturization of the driving force transmission device and driving force transmission mechanism. Furthermore, the rotational speed of the driving-side rotating member is increased in stages, ensuring reliable transmission of driving force even when there are manufacturing errors in the components.

The second disclosure is dependent on the first disclosure and includes a displacement detection sensor for detecting the displacement of the driven member, and the motor control unit controls the motor to increase the rotational speed of the driving-side rotating member when the displacement detection sensor does not detect the displacement of the driven member and the set value of the rotational speed of the driving-side rotating member has not reached a predetermined value.

The third disclosure is dependent on the second disclosure, and the motor control unit stops the motor when the displacement detection sensor does not detect displacement of the driven member and the set value of the rotational speed of the driving-side rotating member reaches a predetermined value.

The fourth disclosure is dependent on the second or third disclosure and includes a displacement detection sensor for detecting the displacement of the driven member, and the motor control unit stops the motor when the displacement detection sensor detects the displacement of the driven member.

The fifth disclosure is dependent on the first or second disclosure, and when a torque equal to or greater than a predetermined value is applied to the driven-side rotating member while the driving-side rotating member is rotating in a first direction, the first cylindrical portion or the second cylindrical portion rotates freely relative to the coil spring.

The sixth disclosure is dependent on the first or second disclosure, and the first direction in which the drive-side rotating member rotates during drive transmission is the direction in which the coil spring contracts in diameter.

The seventh disclosure is an image forming device that forms an image on paper using consumables, and includes a consumable container storage unit provided in the device main body, a consumable container that is removably stored in the consumable container storage unit, and an extrusion mechanism that is provided in the device main body and extrudes the consumable container stored in the consumable container storage unit to a position where it can be removed. The extrusion mechanism includes a support shaft, a driving side rotating member that has a first cylindrical portion through which the support shaft is inserted and is rotatably attached to the support shaft, a driven side rotating member that has a second cylindrical portion through which the support shaft is inserted and is rotatably attached to the support shaft adjacent to the driving side rotating member, and a driven side rotating member that has a second cylindrical portion through which the support shaft is inserted and is rotatably attached to the support shaft, and a An image forming apparatus includes a coil spring into which a first cylindrical portion is press-fitted and a second cylindrical portion is press-fitted at the other end, which transmits the driving force of the driving rotating member to the driven rotating member when the driving rotating member is rotated in a first direction, an arm member that displaces with the rotation of the driven rotating member to push out a consumable container, a motor that rotates the driving rotating member, and a motor control unit that controls the operation of the motor, and the motor control unit controls the motor to gradually increase the rotational speed of the driving rotating member when the driving force is transmitted from the driven rotating member to the arm member to push out the consumable container.

According to the seventh disclosure, the use of a coil spring one-way clutch allows the ejection mechanism to be made smaller. Furthermore, the rotational speed of the drive-side rotating member is increased in stages, ensuring reliable ejection even when there are manufacturing errors in the components.

The eighth disclosure is dependent on the seventh disclosure and includes an arm position detection sensor for detecting displacement of the arm member, and the motor control unit controls the motor to increase the rotation speed of the drive-side rotating member when the arm position detection sensor does not detect displacement of the arm member and the set value of the rotation speed of the drive-side rotating member has not reached a predetermined value.

According to this disclosure, the use of a coil spring one-way clutch allows for the device to be made more compact. Furthermore, the rotational speed of the drive-side rotating member is increased in stages, ensuring reliable transmission of driving force even when there are manufacturing errors in the components.

The above and other objects, features, and advantages of this disclosure will become more apparent from the following detailed description of the embodiments, which proceeds with reference to the drawings.

FIG. 2 is a schematic cross-sectional view showing the internal structure of the image forming apparatus. FIG. 2 is a diagram showing a state in which a toner cartridge is housed in a toner cartridge housing portion. FIG. 2 is a perspective view showing a toner cartridge and a drive unit. FIG. 2 is a perspective view showing a drive unit in a reference state. FIG. 10 is a diagram showing the extrusion mechanism in a reference state as viewed from above. 10 is a diagram showing an eject cam and an eject lever in a reference state as viewed from the front. FIG. 10A and 10B are diagrams illustrating a driving force transmission device included in the extrusion mechanism. FIG. 2 is an exploded perspective view showing the driving force transmission device. FIG. 2 is a cross-sectional view showing a driving force transmission device. FIG. 10 is a diagram showing the ejection mechanism in the ejecting state as viewed from above. FIG. 10 is an illustrative view showing an eject cam and an eject lever in an ejected state as viewed from the front; FIG. 10 is an illustrative view showing a state in which the toner cartridge is in a removable position. FIG. 2 is a block diagram showing an example of an electrical configuration of the image forming apparatus. FIG. 2 is a diagram illustrating an example of a memory map of a RAM. FIG. 10 is a flowchart illustrating an example of an extrusion process by a CPU.

[Example]
1, an image forming apparatus 10 according to an embodiment of the present disclosure is a color printer that forms multicolor or monochrome images on paper (recording media) using an electrophotographic method. As will be described in detail later, the image forming apparatus 10 includes a push-out mechanism 80 (an example of a drive force transmission mechanism) that pushes out a toner cartridge 32 housed in a cartridge housing 52 from a housing position to a removable position. The push-out mechanism 80 includes a drive force transmission device 100 that transmits drive force from a motor 72 to an eject arm 90.

When describing directions in this specification, the front side when viewing the image forming device 10 from the front will be referred to as the "front side," the back side will be referred to as the "rear side," the left side will be referred to as the "left side," the right side will be referred to as the "right side," the top side will be referred to as the "upper side," and the bottom side will be referred to as the "lower side." Furthermore, when describing the toner cartridge 32, the directions will be those when the toner cartridge 32 is housed in the cartridge housing section 52.

First, we will provide an overview of the basic configuration of the image forming device 10. As shown in Figure 1, the image forming device 10 includes components such as a photosensitive drum 12, a developing device 14, a charger 16, a cleaning unit 18, an exposure device 20, an intermediate transfer belt unit 22, a secondary transfer roller 24, and a fixing unit 26. It forms an image on paper transported from a paper feed tray 28 and ejects the paper with the image formed onto a paper output tray 30. Image data input from an external computer is used as the image data for forming the image on the paper. However, if the image forming device 10 has a scanner function, it can also use image data read from a document by a scanner in addition to image data input from an external device.

The above-mentioned components are housed within the device body 10a of the image forming device 10. The device body 10a of the image forming device 10 also includes a control unit including a CPU 150, RAM 154, HDD 156, etc. (see Figure 13). The control unit sends control signals to each part of the image forming device 10, causing the image forming device 10 to perform various operations. Therefore, this control unit also functions as a control unit for the extrusion mechanism 80, which is an example of a drive force transmission mechanism. Although not shown, the device body 10a is also provided with an operation panel that accepts operations from the user. The operation panel is appropriately equipped with a touch panel display (touch panel display) and multiple operation buttons, etc.

Here, the image data handled by the image forming device 10 corresponds to a color image consisting of four colors: black (BK), magenta (M), cyan (C), and yellow (Y). Therefore, four photosensitive drums 12, developing devices 14, chargers 16, and cleaning units 18 are provided, each of which forms four types of latent images corresponding to each color, forming four image stations.

The photoreceptor drum 12 is an image carrier with a photosensitive layer formed on the surface of a conductive substrate, and is rotatable around its axis by a drive unit (not shown). The charger 16 is a device that charges the surface of the photoreceptor drum 12 to a predetermined polarity and potential. The cleaning unit 18 removes and collects toner remaining on the surface of the photoreceptor drum 12 after the toner image is transferred from the photoreceptor drum 12 to the intermediate transfer belt 36. The exposure device 20 is configured as a laser scanning unit (LSU) equipped with a laser emitter and a reflecting mirror, etc., and exposes the charged surface of the photoreceptor drum 12 to light to form an electrostatic latent image on the surface of the photoreceptor drum 12 according to image data.

The developing device 14 visualizes the electrostatic latent image formed on the surface of the photosensitive drum 12 using toner, an example of a consumable item (forming a toner image). A toner cartridge 32, an example of a consumable item container described below, is connected to the developing device 14 via a toner supply pipe 34. The toner cartridge 32 is a container that stores unused toner and carrier (hereinafter, toner and carrier may be collectively referred to as "toner") and is housed in a cartridge storage section 52 (see Figure 2) located above the developing device 14, and supplies toner to the developing device 14.

The intermediate transfer belt unit 22 includes an intermediate transfer belt 36, a drive roller 38, a driven roller 40, and four intermediate transfer rollers 42.

The intermediate transfer belt 36 is a flexible, endless belt that is stretched across multiple rollers, including a drive roller 38 and a driven roller 40, and is positioned so that its surface (outer periphery) abuts against the surface of the photosensitive drum 12. The intermediate transfer belt 36 rotates (circularly moves) in a predetermined direction as the drive roller 38 rotates. The drive roller 38 is rotatable about its axis by a drive unit (not shown). The driven roller 40 rotates in conjunction with the circular movement of the intermediate transfer belt 36, and applies a constant tension to the intermediate transfer belt 36 to prevent slack in the intermediate transfer belt 36.

The intermediate transfer rollers 42 are positioned opposite each photosensitive drum 12 across the intermediate transfer belt 36, and are pressed against the inner surface of the intermediate transfer belt 36, rotating as the intermediate transfer belt 36 rotates. During image formation, a voltage of opposite polarity to the charge polarity of the toner that makes up the toner image formed on the surface of the photosensitive drum 12 is applied to the intermediate transfer rollers 42. The resulting transfer electric field causes the toner image formed on the photosensitive drum 12 to be transferred to the outer surface of the intermediate transfer belt 36.

A secondary transfer roller 24 is positioned opposite the drive roller 38 across the intermediate transfer belt 36. During image formation, a voltage (secondary transfer voltage) is applied to the secondary transfer roller 24, and the toner image formed on the outer surface of the intermediate transfer belt 36 is transferred (secondary transfer) to the paper as the paper passes through the transfer nip area between the intermediate transfer belt 36 and the secondary transfer roller 24 due to the action of the transfer electric field formed thereby. Any toner remaining on the surface of the intermediate transfer belt 36 is then removed and collected by a transfer belt cleaning unit (not shown).

The fixing unit 26 includes a heat roller, a pressure roller, etc., and is positioned above the secondary transfer roller 24. The heat roller is set to a predetermined fixing temperature, and as paper passes through the fixing nip area between the heat roller and the pressure roller, the toner image transferred to the paper is melted, mixed, and pressed against the paper, thermally fixing the toner image to the paper.

In addition, a paper transport path L is formed within the device body 10a of the image forming device 10, for sending paper placed in the paper feed tray 28 to the paper output tray 30 via the secondary transfer roller 24 and the fixing unit 26. Paper transport means such as multiple transport rollers 44 and registration rollers 46 are appropriately arranged along this paper transport path L. During image formation, paper placed in the paper feed tray 28 is guided one sheet at a time into the paper transport path L by a pickup roller (not shown), and is transported to the registration roller 46 by the transport roller 44. The registration roller 46 then transports the paper to the secondary transfer roller 24 when the leading edge of the paper aligns with the leading edge of the toner image on the intermediate transfer belt 36, and the toner image is transferred onto the paper. The paper then passes through the fixing unit 26, where unfixed toner on the paper is thermally melted and fixed, and the paper is ejected onto the paper output tray 30.

Next, we will explain the toner cartridges 32 and cartridge storage compartment 52. Note that Figure 2 shows the state when all toner cartridges 32 are stored in the cartridge storage compartment 52.

As shown in FIG. 2, the device main body 10a is provided with four cartridge storage sections 52, which are an example of consumable container storage sections. A corresponding toner cartridge 32 is removably stored (attached) in each of the four cartridge storage sections 52. For example, an attachment/detachment opening 52a for the cartridge storage section 52 is provided on the front side of the image forming device 10, and the toner cartridge 32 is pushed rearward into the cartridge storage section 52 through the attachment/detachment opening 52a. The toner cartridge 32 is removed by pulling it forward from the cartridge storage section 52.

The device main body 10a also has a front door 10b that can be opened and closed on its front side. When closed, the front door 10b covers the four cartridge storage compartments 52. When open, the front door 10b exposes the front covers 62 of the toner cartridges 32 stored in the cartridge storage compartments 52.

When the toner cartridge 32 is in the storage position, the front of the front cover 62 is positioned at the same position as the attachment/detachment opening 52a of the cartridge storage section 52 in the front-to-rear direction, or slightly behind the attachment/detachment opening 52a of the cartridge storage section 52. Therefore, when the toner cartridge 32 is in the storage position, the user cannot grasp the toner cartridge 32 and is unable or unable to remove the toner cartridge 32 from the cartridge storage section 52.

Figure 3 shows the toner cartridge 32 connected to the drive unit 70 provided inside the device main body 10a. The drive unit 70 is provided at the back (rear) of the cartridge storage section 52, and the toner cartridge 32 and drive unit 70 are connected when the toner cartridge 32 is stored in the cartridge storage section 52 (moved to the storage position).

As shown in FIG. 3, the toner cartridge 32 comprises a container body 60, a front cover 62, and a cartridge-side connector 64. The container body 60 is a rectangular cylindrical container that is long in the front-to-rear direction and contains toner. Although not shown, a toner discharge mechanism is provided inside the container body 60, and a toner discharge outlet is formed at the rear end of the container body 60. The toner discharge mechanism includes an auger screw that transports toner toward the toner discharge outlet, and an agitator that agitates the toner in the container body 60 to loosen it and supplies toner to the auger screw. The container body 60 may also have other shapes, such as a cylindrical shape.

The front cover 62 is removably attached to the front end of the toner cartridge 32. This front cover 62 functions as a lid that covers the front opening of the container body 60. In addition, the front end of the toner cartridge 32, including the front cover 62, functions as a grip that the user can grasp when removing the toner cartridge 32 from the cartridge storage section 52.

Furthermore, the cartridge-side connector 64 (hereinafter simply referred to as "connector 64") is provided at the rear end of the container body 60. Although not shown, the connector 64 has terminals that are electrically connected to a CRUM chip 68 (see Figure 13) provided on the toner cartridge 32. For example, the CRUM chip 68 is provided inside the socket of the connector 64. This CRUM chip 68 stores model information indicating the model of the image forming device 10 to which the toner cartridge 32 is applied, identification information for the toner cartridge 32, information for managing toner replenishment, and the like.

When the toner cartridge 32 is stored in the cartridge storage section 52, the connector 64 connects to a main body connector (not shown) provided in the cartridge storage section 52. The main body connector has a terminal that is electrically connected to the communication unit 158 (see Figure 13) of the device main body 10a, and by connecting the connector 64 to the main body connector, the CRUM chip 68 and the communication unit 158 (and therefore the CPU 150) are electrically connected and capable of communication.

Furthermore, when the toner cartridge 32 is in the storage position, the toner discharge port formed in the container body 60 is connected to the toner supply pipe 34, and toner discharged from the toner discharge port is replenished to the developing device 14 via the toner supply pipe 34. In other words, the toner cartridge 32 is ready for use. However, the storage position refers to the rearmost position of the toner cartridge 32 when inserted into the cartridge storage section 52, and is the position at which the toner cartridge 32 cannot be moved any further rearward.

Referring to Figure 4 together with Figure 3, the drive unit 70 includes a motor 72, a drive transmission member 74, a drive transmission member 76, and an extrusion mechanism 80. However, in Figure 4, part of the upper cover of the drive unit 70 is omitted.

Motor 72 is a general-purpose motor such as a stepping motor, and is capable of switching between forward and reverse rotation. The direction and number of rotations (pulse rate) of motor 72 are switched according to instructions from the control unit (CPU 150) of image forming apparatus 10.

The drive transmission member 74 and the drive transmission member 76 are each a member for transmitting the rotational driving force of the motor 72, which is the drive source, to the auger screw or agitator member provided inside the toner cartridge 32. The drive transmission member 74 and the drive transmission member 76 are provided forward of the motor 72. The rotational axes of the drive transmission member 74 and the drive transmission member 76 are in the front-to-rear direction.

When the toner cartridge 32 and drive unit 70 are connected, the drive transmission member 74 is connected to the auger screw of the toner cartridge 32. Furthermore, when the toner cartridge 32 and drive unit 70 are connected, the drive transmission member 76 is connected to the agitator member of the toner cartridge 32. Therefore, the auger screw is rotated by the rotational drive force transmitted from the drive transmission member 74, and the agitator member is rotated by the rotational drive force transmitted from the drive transmission member 76.

The rotational drive force is transmitted to the drive transmission member 74 and the drive transmission member 76 regardless of the rotation direction of the motor 72. However, the auger screw transports toner toward the rear when the motor 72 is rotated forward. In other words, when the toner is being discharged, the motor 72 is rotated forward. As a result, the toner in the container body 60 is transported toward the rear while being agitated by the auger screw and the agitator, and is supplied to the developing device 14 through the toner discharge port formed at the rear end of the container body 60 via the toner supply pipe 34.

On the other hand, when the motor 72 rotates in the reverse direction, the push-out mechanism 80 is activated, and the push-out mechanism 80 pushes out (ejects) the toner cartridge 32. In other words, the motor 72 serves both as a motor that drives the push-out mechanism 80 and as a motor that drives the toner discharge mechanism of the toner cartridge 32. The rotation direction of the motor 72 when the push-out mechanism 80 pushes out the toner cartridge 32 is set to be opposite to the rotation direction of the motor 72 when the toner discharge mechanism discharges toner from the toner cartridge 32.

An example of the configuration of the extrusion mechanism 80 will be described in detail below with reference to Figures 4 to 6. Note that Figures 4 to 6 show the extrusion mechanism 80 in its standard state.

As shown in Figures 4-6, the push-out mechanism 80 is a mechanism that uses the driving force of the motor 72 to push the toner cartridge 32 stored in the cartridge storage unit 52 from its storage position to its removal position. The push-out mechanism 80 includes a drive transmission device 100 that includes a drive gear 82, a coil spring 84, and an eject cam 86, as well as an eject lever 88, an eject arm 90, a shaft support member 92, a biasing member 94, and an arm position detection sensor 96.

Note that in Figures 4-6, the eject lever 88 and eject arm 90 are shaded for clarity. The same applies to Figures 10 and 11. Also, although it is difficult to see in Figure 4, the eject arm 90 is located below the coupling gear of the drive transmission member 76.

The drive transmission device 100 transmits the driving force from the motor 72 to the eject arm 90 via the eject lever 88, and includes a drive gear 82, a coil spring 84, and an eject cam 86. The drive gear 82 is located forward of the motor 72, and its rotational axis is in the front-to-rear direction. When the motor 72 rotates forward, the drive gear 82 rotates clockwise as viewed from the front, and when the motor 72 rotates reverse, the drive gear 82 rotates counterclockwise as viewed from the front. Furthermore, the rotational axes of the coil spring 84 and the eject cam 86 also extend in the front-to-rear direction, and the drive gear 82, coil spring 84, and eject cam 86 are arranged coaxially.

This driving force transmission device 100 has a one-way clutch function, as described below, and transmits the rotational force to the eject cam 86 when the drive gear 82 rotates in a first direction (counterclockwise in this embodiment). In other words, when the motor 72 rotates forward, the rotational drive force is not transmitted to the eject cam 86; the rotational drive force is transmitted to the eject cam 86 only when the motor 72 rotates reversely. This driving force transmission device 100 also has a torque limiter function. The specific configuration of the driving force transmission device 100 will be described later.

The eject lever 88 is disposed between the eject cam 86 and the eject arm 90. The eject lever 88 has a shaft 88a, an arm 88b, and a gear 88c. The shaft 88a is cylindrical and rotatably supported by a vertically extending shaft 92a formed on the shaft support member 92. Therefore, the eject lever 88 can rotate horizontally around the shaft 92a. The arm 88b is L-shaped and extends rearward from the shaft 88a. The arm 88b is biased toward the eject cam 86 by one end 94a of a biasing member (torsion spring) 94 attached to the outer peripheral surface of the shaft 88a, and abuts against the left outer surface of the eject cam 86. Therefore, the eject lever 88 rotates so that the arm 88b moves left and right as the eject cam 86 rotates, i.e., depending on the rotational position of the eject cam 86. Gear 88c is formed in an arc shape and protrudes forward from shaft portion 88a. This gear 88c is an externally toothed gear that meshes with gear 90d of eject arm 90, which will be described later. However, the tooth shapes of gears 88c and 90d are omitted from Figures 4 and 5 (as well as Figure 10).

The eject arm 90 (an example of a driven member) is an arm member disposed in front of the eject lever 88. The eject arm 90 has a shaft portion 90a, an arm portion 90b, a contact portion 90c, a gear 90d, and a protrusion 90e. The shaft portion 90a is cylindrical and is rotatably supported by a shaft 92b extending vertically of the shaft support member 92. Therefore, the eject arm 90 can rotate horizontally around the shaft 92b, and the rotation axis of the eject arm 90 is parallel to the rotation axis of the eject lever 88. The arm portion 90b extends to the right from the shaft portion 90a, and a contact portion 90c that protrudes forward is formed at the right end (tip) of the arm portion 90b. This contact portion 90c is the portion that abuts against the rear end of the toner cartridge 32 during the ejection operation. The gear 90d is formed in an arc shape and projects rearward from the shaft portion 90a. This gear 90d is an externally toothed gear that meshes with the gear 88c of the eject lever 88. As a result, the eject arm 90 rotates so that the contact portion 90c moves forward and backward as the eject lever 88 rotates. The biasing force of the biasing member 94 acts on the eject arm 90 in a direction that moves the contact portion 90c away from the toner cartridge 32. Furthermore, a protrusion 90e is formed on the front surface of the longitudinal center of the eject arm 90 so as to protrude forward.

The shaft support member 92 includes a shaft 92a, a shaft 92b, a base 92c, and a support post 92d. Although not shown in the figure, the shaft support member 92 is fixed to the device main body 10a. The base 92c is a flat plate-shaped member, and in addition to the shafts 92a and 92b, a support post 92d is provided on the upper surface of the base 92c. The support post 92d is a rectangular pillar extending in the vertical direction, and the other end 94b of the biasing member 94 is engaged with this support post 92d.

The arm position detection sensor 96 (an example of a displacement detection sensor) is a sensor for detecting the position information, or displacement, of the eject arm 90, and is positioned in front of the eject arm 90. The arm position detection sensor 96 is, for example, a photosensor having a light-emitting element and a light-receiving element, and is configured so that when the eject arm 90 reaches the eject position, the protrusion 90e of the eject arm 90 blocks the light from the light-emitting element. In other words, the arm position detection sensor 96 is a sensor that can detect whether the eject arm 90 is in the eject position (i.e., whether the eject arm 90 is displaced or not).

Next, the configuration of the driving force transmission device 100 will be described in detail with reference to Figures 7-9. As shown in Figures 7-9, the driving force transmission device 100 includes a driving gear 82, which is an example of a driving-side rotating member, a coil spring 84, an eject cam 86, which is an example of a driven-side rotating member, and a support shaft 98.

The support shaft 98 is a fixed, generally cylindrical metal shaft that extends in the front-to-rear direction. This support shaft 98 rotatably supports the drive gear 82 and eject cam 86.

The drive gear 82 is a component for transmitting the rotational driving force of the motor 72 to the eject cam 86 and is connected to the eject cam 86 via a coil spring 84. The drive gear 82 has a circular plate-shaped base 82a, a first cylindrical portion 82b (first shaft portion) protruding forward (toward the eject cam 86) from the center of the base 82a, and a cylindrical gear portion 82c provided on the periphery of the base 82a so as to cover the periphery of the first cylindrical portion 82b. Although not shown, gear teeth are provided on the outer peripheral surface of the gear portion 82c. The drive gear 82 is rotatably mounted on the support shaft 98 forward of the motor 72 by inserting the support shaft 98 into the first cylindrical portion 82b. When the motor 72 of the drive unit 70 rotates forward, the drive gear 82 rotates clockwise when viewed from the front, and when the motor 72 of the drive unit 70 rotates reversely, the drive gear 82 rotates counterclockwise when viewed from the front.

The eject cam 86 is a cam member located adjacent to the drive gear 82 on the front side of the drive gear 82. The eject cam 86 has a circular plate-shaped base 86a, a second cylindrical portion 86b (second shaft portion) that protrudes rearward (toward the drive gear 82) from the center of the base 86a, and a substantially cylindrical cam portion 86c formed on the periphery of the base 86a. In this embodiment, the eject cam 86 is a flat cam, and the cam portion 86c has a protrusion 86d that protrudes tangentially from its outer periphery. The eject cam 86 is rotatably attached to the support shaft 98 by inserting the support shaft 98 into the second cylindrical portion 86b so that the first cylindrical portion 82b and the second cylindrical portion 86b face each other. The eject cam 86 is then rotated by the rotational driving force transmitted from the drive gear 82 via the coil spring 84.

The coil spring 84 is a component for transmitting the rotational driving force of the drive gear 82 to the eject cam 86 when the drive gear 82 rotates in a first direction (counterclockwise in this embodiment). In this embodiment, a square spring with a rectangular cross section is used as the coil spring 84. The first cylindrical portion 82b of the drive gear 82 is press-fitted into one end of the coil spring 84, and the second cylindrical portion 86b of the eject cam 86 is press-fitted into the other end, thereby interlocking the drive gear 82 and the eject cam 86. In this case, the coil spring 84 is attached to the first cylindrical portion 82b and the second cylindrical portion 86b so that its diameter contracts when the drive gear 82 rotates in the first direction. In other words, the first direction in which the drive gear 82 rotates when transmitting drive is the direction in which the coil spring 84 contracts in diameter, and the tip of the wire constituting the coil spring 84 on the drive gear 82 side extends in the first direction.

In this driving force transmission device 100, when the motor 72 rotates forward and the drive gear 82 rotates in the second direction (clockwise in this embodiment), as described below, when the ejection mechanism 80 is in the reference state and a torque greater than a predetermined value is applied to the eject cam 86, the coil spring 84 expands in diameter (i.e., loosens), resulting in a limiter slip state in which the first cylindrical portion 82b or the second cylindrical portion 86b rotates freely relative to the coil spring 84. As a result, the rotational driving force is not transmitted to the eject cam 86, and the eject arm 90 does not operate. On the other hand, when the motor 72 rotates reversely and the drive gear 82 rotates in the first direction, the coil spring 84 contracts in diameter (i.e., tightens), ensuring that the rotational driving force is transmitted from the drive gear 82 to the eject cam 86, ultimately operating the eject arm 90. In other words, in the driving force transmission device 100, the action of the coil spring 84 provides a one-way clutch function.

Furthermore, in the driving force transmission device 100, even if the motor 72 rotates in the reverse direction and the drive gear 82 rotates in the first direction, if some malfunction occurs and a torque greater than a predetermined level is applied to the eject cam 86, the first cylindrical portion 82b or the second cylindrical portion 86b will rotate freely relative to the coil spring 84, resisting the frictional force with the coil spring 84. In other words, the driving force transmission device 100 also exhibits a torque limiter function due to the action of the coil spring 84.

In this way, by providing the coil spring 84 with one-way clutch functionality (i.e., employing a coil spring-type one-way clutch), the driving force transmission device 100 can achieve one-way clutch functionality with a simpler configuration than other types of one-way clutches, such as ratchet and sprag types, and can make the device more compact. Furthermore, because it also has a torque limiter function, it can be ideally used in the extrusion mechanism 80, contributing to space savings.

Next, the pushing operation of the toner cartridge 32 by the pushing mechanism 80 will be described with reference to Figures 4-6, 10, and 11. The pushing operation refers to the operation of pushing the toner cartridge 32 from the storage position to the removal position. Note that Figures 10 and 11 show the state when the pushing mechanism 80 is in the eject state, that is, when the toner cartridge 32 has been pushed out to the removal position.

This extrusion operation is performed automatically by instruction from the CPU 150 of the device main body 10a when it is determined that the toner cartridge 32 needs to be replaced. The toner cartridge 32 needs to be replaced, for example, when the toner in the toner cartridge 32 falls below a predetermined amount, when a toner replenishment error occurs in the toner cartridge 32, or when an incorrect toner cartridge is inserted into the cartridge storage section 52. Whether the toner in the toner cartridge 32 has fallen below a predetermined amount (i.e., the remaining toner amount) is determined (detected) by whether the total number of rotations of the toner cartridge 32's auger screw is above a threshold, whether the total number of counted print dots is above a threshold, whether the toner drop detection from the toner cartridge 32 detects no toner drop, etc.

As can be seen clearly from Figures 5 and 6, when the extrusion mechanism 80 is in the standard state, the eject arm 90 is located in the rearmost arm standard position. In this standard state, there is a small gap between the contact portion 90c of the eject arm 90 and the rear end of the toner cartridge 32.

Furthermore, when the extrusion mechanism 80 is in the reference state, the eject cam 86 is located in a cam reference position where the upper surface of the protrusion 86d abuts against the lower surface of the arm 88b of the eject lever 88. Therefore, in this reference state, when normal toner transport operation is performed in the toner cartridge 32, that is, when the motor 72 is rotated forward, the one-way clutch (coil spring 84) of the driving force transmission device 100 enters a limiter slip state. Therefore, even if the motor 72 is rotated forward during normal toner transport operation, the eject cam 86 does not rotate, and therefore the eject lever 88 and eject arm 90 do not move. In other words, the reference state is maintained.

When it is determined that the toner cartridge 32 needs to be replaced, the ejection operation is initiated from this reference state. When the ejection operation is performed, the motor 72 is rotated in reverse. When the motor 72 is rotated in reverse, a driving force is transmitted from the drive gear 82 via the coil spring 84 to the eject cam 86, causing the eject cam 86 to rotate counterclockwise as viewed from the front. However, the rotation angle of the motor 72 of the drive unit 70 during the ejection operation is basically set so that the eject cam 86 rotates once by controlling the rotation time of the motor 72.

As the eject cam 86 rotates counterclockwise from the cam reference position, the left side of the arm 88b of the eject lever 88 rides up on the protrusion 86d during one rotation. Then, as shown in Figures 10 and 11, the arm 88b of the eject lever 88 moves to the left, and against the biasing force of the biasing member 94, the eject lever 88 rotates counterclockwise as viewed from above. This causes the eject arm 90 to rotate clockwise as viewed from above, and the abutment portion 90c moves from the rear side to the front side. At this time, the abutment portion 90c pushes the toner cartridge 32, which is in the storage position, forward, moving the toner cartridge 32 to the removal position. In other words, when the push-out mechanism 80 enters the eject state, the toner cartridge 32 is pushed to the removal position where the front end of the toner cartridge 32 protrudes from the attachment/detachment opening 52a of the cartridge storage section 52.

When the eject cam 86 continues to rotate counterclockwise from the eject state, the arm 88b of the eject lever 88 moves over the protrusion 86d of the eject cam 86 and is then moved to the right by the biasing force of the biasing member 94. Accordingly, the eject arm 90 rotates counterclockwise when viewed from above, and the abutment portion 90c moves from the front to the rear. In other words, the eject arm 90 returns to the arm reference position, and the extrusion mechanism 80 returns to the reference state. However, because the abutment portion 90c and the toner cartridge 32 are no longer connected, the toner cartridge 32 remains in the removal position.

As shown in FIG. 12, when the toner cartridge 32 is in the removable position, the front end of the toner cartridge 32 protrudes forward from the attachment/detachment opening 52a of the cartridge storage section 52. For example, the removable position is a position where the toner cartridge 32 has moved approximately 15 mm to 20 mm forward from the storage position. In other words, it is a position where the front end of the toner cartridge 32 protrudes approximately 15 mm to 20 mm forward from the attachment/detachment opening 52a of the cartridge storage section 52. In this case, the user can grasp the front end of the toner cartridge 32 and easily remove the cartridge storage section 52 from the cartridge storage section 52.

The distance the toner cartridge 32 is pushed forward by the ejection mechanism 80 is set to be shorter than the distance (gap) between the front end of the toner cartridge 32 in the storage position (the front surface of the front cover 62) and the front door 10b of the device main body 10a when it is closed. This is to prevent the front end of the toner cartridge 32 pushed forward by the ejection operation from colliding with the front door 10b of the device main body 10a.

Figure 13 is a block diagram showing an example of the electrical configuration of the image forming device 10. However, some components not directly related to the present invention have been omitted.

As shown in FIG. 13, the image forming device 10 includes a CPU 150, which is connected to a RAM 154 and an HDD 156 via a bus 152. The CPU 150, RAM 154, HDD 156, etc., form the control unit of the image forming device 10. The CPU 150 is also connected to a communication unit 158, a motor 72, etc. via the bus 152. The communication unit 158 is also connected to the CRUM chip 68 of the toner cartridge 32.

The CPU 150 is responsible for overall control of the image forming apparatus 10 in accordance with the programs stored in the HDD 156. The CPU 150 is also the control means that executes the extrusion process in this embodiment, and functions as a motor control unit that controls the operation of the motor 72. The RAM 154 is used as a working area and buffer area for the CPU 150. The HDD 156 stores control programs and necessary data, etc., that the CPU 150 uses to control the operation of each part of the image forming apparatus 10. However, other non-volatile memory such as an SSD, flash memory, or EEPROM may be used instead of or in addition to the HDD 156.

The communication unit 158 is a communication circuit for communicating with the CRUM chip 68 provided in the toner cartridge 32, and communicates with the CRUM chip 68 in accordance with instructions from the CPU 150.

As described above, motor 72 is a motor that drives the toner discharge mechanism of toner cartridge 32 and also drives extrusion mechanism 80. Motor 72 is driven in accordance with instructions from CPU 150, and by rotating forward or reverse, provides driving force to the toner discharge mechanism of toner cartridge 32 and extrusion mechanism 80.

The operation of the push-out mechanism 80 as described above is performed by controlling the rotation direction, rotation speed, and drive time (i.e., number of rotations) of the motor 72. However, if there are manufacturing errors in the components that make up the push-out mechanism 80, it may not be possible to properly push out the toner cartridge 32. In particular, when a coil spring-type one-way clutch is used, depending on manufacturing errors and environmental conditions, even if the drive gear 82 is rotated in the first direction, the coil spring 84 may not engage and slip, preventing the drive force from being transmitted to the eject cam 86.

Therefore, in this embodiment, the rotation speed (pulse rate) of the motor 72 is controlled so that the rotation speed of the drive gear 82 is increased in stages from low to high, thereby ensuring reliable ejection even when there are manufacturing errors in the components that make up the drive transmission device 100 (drive gear 82, coil spring 84, eject cam 86, etc.). This is based on the findings of verification experiments conducted by the inventors that, while it would normally be thought that power transmission is easier at low speeds, components without manufacturing errors will actually operate at low speeds (low rotation speeds), and components without manufacturing errors will not operate at low speeds but will engage and operate as the speed increases (high rotation speeds). It is also possible to set the rotation speed to high from the beginning, but this would mean that, although there would be no manufacturing error, the engagement force would be too strong, which could cause the toner cartridge 32 to eject at high speed. It would also raise the upper limit of the torque limiter, which could affect the effectiveness of preventing user injury and could result in parts being worn down by friction between metals, shortening their lifespan. For these reasons, the rotation speed of the drive gear 82 is increased in stages.

Specifically, when performing the ejection operation, the motor 72 is first rotated in reverse for a predetermined time (the time required for one rotation of the eject cam 86) at an initial value set to a low rotation speed (for example, 300 ppm). If the arm position detection sensor 96 detects displacement of the eject arm 90 during this operation, it is determined that the ejection operation has been performed properly, and the motor 72 is stopped, ending the ejection operation.

On the other hand, if the arm position detection sensor 96 does not detect any displacement of the eject arm 90 (i.e., it does not detect that the motor 72 is in the eject position) even when the motor 72 is rotated in reverse, it is determined that the ejection operation was not performed properly. In this case, if the set value of the motor 72 rotation speed (i.e., the set value of the rotation speed of the drive gear 82) has not reached a predetermined value (e.g., 700 ppm), the motor 72 rotation speed is set to a high value (e.g., 700 ppm), and the motor 72 is rotated in reverse again for a predetermined period of time. On the other hand, if the set value of the motor 72 rotation speed has reached the predetermined value, the motor 72 is stopped, and the user is notified that an eject error has occurred, for example by displaying an error on the display.

Figure 14 is a diagram showing an example of a memory map 200 of RAM 154. As shown in Figure 14, RAM 154 includes a program storage area 202 and a data storage area 204. The program storage area 202 of RAM 154 stores an image formation program 202a, an extrusion condition determination program 202b, a communication program 202c, an extrusion control program 202d, and the like.

The image forming program 202a is a program for controlling components such as the photosensitive drum 12 to print multi-color or monochrome images on paper. The extrusion condition determination program 202b is a program for determining whether the toner cartridge 32 needs to be replaced. The communication program 202c is a program for sending and receiving necessary information to and from the CRUM chip 68 of the toner cartridge 32. The extrusion control program 202d is a program for controlling the motor 72 to cause the extrusion mechanism 80 to perform an extrusion operation. This extrusion control program 202d includes a rotation control program that controls the rotation speed of the motor 72 so as to gradually increase the rotation speed of the drive gear 82 from low to high.

Although not shown in the figure, the program storage area 202 also stores other programs for executing various functions by the CPU 150 as appropriate.

In addition, the data storage area 204 of the RAM 154 stores an image data buffer 204a, a remaining toner amount data buffer 204b, and rotation condition data 204c.

Image data buffer 204a is a buffer for temporarily storing image data and the like transmitted from an external computer. Remaining toner amount data buffer 204b is a buffer for temporarily storing the remaining toner amount in toner cartridge 32 transmitted from toner cartridge 32. Rotation condition data 204c is data regarding rotation conditions such as the rotation speed (initial value, increment, etc.) and rotation time of motor 72 used when performing the extrusion operation by extrusion mechanism 80.

Although not shown in the figure, the data storage area 204 may be provided with timers (counters) or registers required for executing the control program, and may also store other data required for executing the control program.

Figure 15 is a flow diagram showing an example of the extrusion process (ejection process) executed by the CPU 150 of the image forming device 10. This extrusion process is initiated when it is determined that the toner cartridge 32 needs to be replaced, for example, when the toner in the toner cartridge 32 falls below a predetermined amount.

As shown in FIG. 15, when the extrusion process begins, the CPU 150 sets the rotation speed N of the motor 72 to an initial value (e.g., 300 ppm) in step S1. In the next step S3, a control signal is sent to the motor 72, causing the motor 72 to rotate in reverse at the set rotation speed N.

In the following step S5, it is determined whether a predetermined time has elapsed. In other words, it is determined whether the time required for the eject cam 86 to rotate once has elapsed. If the answer is "NO" in step S5, the process waits until the predetermined time has elapsed. On the other hand, if the answer is "YES" in step S5, the process proceeds to step S7.

In step S7, it is determined whether ejection has been detected. That is, a detection signal is obtained from the arm position detection sensor 96, and it is determined whether the eject arm 90 has reached the eject position during the predetermined time that the motor 72 is rotated in reverse. If the answer is "YES" in step S7, the process proceeds to step S9, where a stop signal is sent to the motor 72, and the ejection process is terminated. On the other hand, if the answer is "NO" in step S7, the process proceeds to step S11.

In step S11, it is determined whether the set value of the rotation speed N is equal to or greater than a predetermined value (for example, 700 ppm). If the answer is "YES" in step S11, the process proceeds to step S13. In step S13, a stop signal is sent to the motor 72 and an error notification is executed. For example, a control signal is sent to the display of the operation panel, and a message indicating that an ejection error has occurred is displayed on the display. The ejection process then ends. On the other hand, if the answer is "NO" in step S11, the process proceeds to step S15. In step S15, the set value of the rotation speed N of the motor 72 is increased. That is, the rotation speed N of the motor 72 is set to a high rotation speed (for example, 700 ppm), and the process returns to step S3.

As described above, this embodiment employs a coil spring one-way clutch, which allows for the miniaturization of the driving force transmission device 100 (and thus the push-out mechanism 80, which is an example of a driving force transmission mechanism). Furthermore, by gradually increasing the rotation speed of the motor 72 (and thus the rotation speed of the drive gear 82, which is an example of a drive-side rotating member), driving force can be reliably transmitted and the push-out operation can be reliably performed even if there are manufacturing errors in the components. Furthermore, by gradually increasing the rotation speed of the motor 72, it is possible to prevent the toner cartridge 32 from popping out at high speed and the torque limiter's upper limit from increasing, thereby ensuring safety and preventing a reduction in the lifespan of the components.

The configuration of the ejection mechanism 80 described above is merely one example, and can be modified as appropriate without departing from the spirit of the present invention. For example, in the above embodiment, a planar cam was used as the cam member (eject cam) of the ejection mechanism, combined with an eject lever, but a three-dimensional cam could also be used as the cam member. That is, in the above embodiment, the eject arm (driven member) receives driving force from the eject cam (driven rotating member) of the driving force transmission device via the eject lever, but the driving force could also be transmitted directly from the eject cam.

In addition, in the above-described embodiment, a coil spring with a rectangular cross section (i.e., a square spring) was used, but the cross-sectional shape of the coil spring is not particularly limited; for example, a coil spring with a circular cross section could also be used. Also, while a cam member was used as the driven rotating member, the driven rotating member could also be a gear member. Furthermore, when gradually increasing the rotational speed of the driving rotating member, the rotation speed of the motor 72 was increased in two stages: low speed (300 ppm) and high speed (700 ppm), but it could also be increased in three or more stages (e.g., low speed, medium speed, and high speed).

Furthermore, in the above-described embodiment, the displacement of the eject arm (driven member) is directly detected by the arm position detection sensor, but the displacement of the eject arm may also be detected indirectly by detecting the displacement of the toner cartridge. In other words, the arm position detection sensor (displacement detection sensor) also includes the toner cartridge position detection sensor.

Furthermore, in the above-described embodiment, a color printer was used as an example of the image forming device, but the image forming device may also be a monochrome printer. Furthermore, the image forming device does not have to be limited to a printer, but may also be a copier, facsimile, or multifunction device equipped with these functions.

In addition, in the above-described embodiment, a toner cartridge is used as an example of a consumable container, but the consumable container is not limited to a toner cartridge and may be a toner bottle. Furthermore, liquid toner may be used as the consumable toner. In this case, the consumable container is a liquid toner container. Furthermore, in the above-described embodiment, an electrophotographic image forming apparatus is used as an example, but this does not necessarily mean that it is limited to this. In the case of an inkjet image forming apparatus, the consumable is ink. Therefore, the consumable container that stores the consumable ink is an ink cartridge or an ink bottle. Furthermore, the drive force transmission mechanism of this invention can be applied to devices other than image forming apparatuses.

Furthermore, the specific numerical values and part shapes listed above are merely examples and can be changed as needed depending on the product specifications, etc.

10 ... image forming apparatus 10a ... apparatus main body 32 ... toner cartridge (consumable container)
52 ... Cartridge storage section (consumables container storage section)
70: Drive unit 72: Motor 80: Extrusion mechanism (driving force transmission mechanism)
82 ... Drive gear (drive side rotating member)
84 ... coil spring 86 ... eject cam (driven side rotating member)
88 ... Eject lever 90 ... Eject arm (driven member, arm member)
94 ... biasing member 96 ... arm position detection sensor (displacement detection sensor)
98 ... Support shaft 100 ... Driving force transmission device 150 ... CPU (motor control unit)

Claims (8)

A driving force transmission mechanism including a driving force transmission device that transmits driving force from a motor to a driven member,
The driving force transmission device is
support shaft,
a drive-side rotating member having a first cylindrical portion through which the support shaft is inserted and attached rotatably to the support shaft;
a driven-side rotating member having a second cylindrical portion through which the support shaft is inserted, the driven-side rotating member being attached adjacent to the driving-side rotating member so as to be rotatable with respect to the support shaft, and transmitting a driving force to the driven-side rotating member; and a coil spring having one end side into which the first cylindrical portion is press-fitted and the other end side into which the second cylindrical portion is press-fitted, transmitting the driving force of the driving-side rotating member to the driven-side rotating member when the driving-side rotating member is rotated in a first direction,
the motor that rotates the drive-side rotation member; and a motor control unit that controls the operation of the motor,
The motor control unit controls the motor so as to increase the rotation speed of the driving-side rotating member in stages when transmitting driving force from the driven-side rotating member to the driven member. a displacement detection sensor for detecting the displacement of the driven member;
2. The driving force transmission mechanism according to claim 1, wherein the motor control unit controls the motor to increase the rotational speed of the driving-side rotating member when the displacement of the driven member is not detected by the displacement detection sensor and the set value of the rotational speed of the driving-side rotating member has not reached a predetermined value. A driving force transmission mechanism as described in claim 2, wherein the motor control unit stops the motor when the displacement detection sensor does not detect displacement of the driven member and the set value of the rotational speed of the driving-side rotating member reaches a predetermined value. A driving force transmission mechanism according to claim 2 or 3, wherein the motor control unit stops the motor when the displacement detection sensor detects displacement of the driven member. A driving force transmission mechanism according to claim 1 or 2, wherein when a torque equal to or greater than a predetermined value is applied to the driven rotating member while the driving rotating member is rotating in the first direction, the first cylindrical portion or the second cylindrical portion rotates freely relative to the coil spring. A driving force transmission mechanism according to claim 1 or 2, wherein the first direction in which the drive-side rotating member rotates during drive transmission is the direction in which the coil spring contracts in diameter. An image forming apparatus that forms an image on a sheet using consumables,
a consumables container storage section provided in the device body;
a consumable container that is removably stored in the consumable container storage section; and an ejection mechanism that is provided in the device body and that ejects the consumable container stored in the consumable container storage section to a position where the consumable container can be removed,
The extrusion mechanism includes:
support shaft,
a drive-side rotating member having a first cylindrical portion through which the support shaft is inserted and attached rotatably to the support shaft;
a driven-side rotating member having a second cylindrical portion through which the support shaft is inserted, the driven-side rotating member being adjacent to the drive-side rotating member and rotatably attached to the support shaft;
a coil spring into which the first cylindrical portion is press-fitted at one end and the second cylindrical portion is press-fitted at the other end, the coil spring transmitting the driving force of the driving-side rotating member to the driven-side rotating member when the driving-side rotating member is rotated in a first direction;
an arm member that is displaced in accordance with the rotation of the driven rotation member to push out the consumable container;
a motor that rotates the driving-side rotating member; and a motor control unit that controls the operation of the motor,
The motor control unit controls the motor to gradually increase the rotational speed of the drive-side rotating member when transmitting a driving force from the driven-side rotating member to the arm member to push out the consumable container. an arm position detection sensor for detecting displacement of the arm member;
8. The image forming apparatus according to claim 7, wherein the motor control unit controls the motor to increase the rotation speed of the driving side rotating member when the arm position detection sensor does not detect displacement of the arm member and the set value of the rotation speed of the driving side rotating member has not reached a predetermined value.