Patent Application
20250231519
The present disclosure relates generally to image forming devices and more particularly to hold down assemblies for a developer unit of an electrophotographic image forming device.
During the electrophotographic printing process, an electrically charged rotating photoconductive drum is selectively exposed to a laser beam. The areas of the photoconductive drum exposed to the laser beam are discharged, creating an electrostatic latent image of a page to be printed on the photoconductive drum. Toner particles from a developer roll are then electrostatically transferred to the latent image on the photoconductive drum, creating a toned image on the drum. The toned image is transferred to the print media (e.g., paper) either directly by the photoconductive drum or indirectly by an intermediate transfer member. The toner is then fused to the media using heat and pressure to complete the print.
The image forming device's toner supply is typically stored in one or more replaceable units having a shorter lifespan than the image forming device. Some image forming devices include a first replaceable unit in the form of a toner cartridge that holds a main toner supply of the image forming device and feeds toner through an outlet port of the toner cartridge to an inlet port of a second replaceable unit, sometimes referred to as an imaging unit or a developer unit. It is important that the replaceable units are rigidly held in place within the image forming device in order to prevent the positional alignment of the replaceable units from being disturbed during operation. For example, in the case of a single component development system, the developer roll in the developer unit contacts the photoconductive drum during the printing process. For good print quality, it is desired for the developer roll to be in uniform contact with a corresponding photoconductive drum of a photoconductor unit along the length of photoconductive drum's centerline. As a result, a mechanism that rigidly holds down the developer roll in place is desired.
A toner container for use with a developer unit of an image forming device includes a body having a reservoir for holding toner and an engagement arm that is movable relative to the body between a disengaged position and an engaged position. The engagement arm includes a first engagement surface for contacting a cam surface in the image forming device and receiving an actuation force from the cam surface to move the engagement arm from the disengaged position to the engaged position when the toner container is inserted into the image forming device. The engagement arm includes a second engagement surface for contacting and applying a hold-down force on a portion of the developer unit when the engagement member moves from the disengaged position to the engaged position when the toner container is inserted into the image forming device with the developer unit installed in the image forming device. In some embodiments, the engagement arm is spring biased towards a top of the body. In some embodiments, the engagement arm is spring biased towards the disengaged position.
Embodiments include those wherein the first engagement surface includes an upper end of the engagement arm and the second engagement surface includes a lower end of the engagement arm. In some embodiments, the lower end of the engagement arm extends downward past a bottom of the body when the engagement arm is in the engaged position.
A toner container for use with a developer unit of an image forming device according to another example embodiment includes a body having a reservoir for holding toner, an outlet port on the body for exiting toner from the toner container to the developer unit, and an engagement member movably mounted on the body. An upper end of the engagement member is positioned to receive an actuation force from a corresponding cam surface in the image forming device that causes the engagement member to move downward relative to the body and a lower end of the engagement member is unobstructed to contact and push downward on a portion of the developer unit to apply a hold-down force on the developer unit when the toner container is inserted into the image forming device with the developer unit installed in the image forming device.
In some embodiments, a biasing member biases the engagement member upward. In some embodiments, the lower end of the engagement member extends downward past a bottom of the body upon the upper end of the engagement member receiving the actuation force.
A toner container for use with a developer unit of an image forming device according to another example embodiment includes a body having a reservoir for holding toner, and a hold-down mechanism on the body. The hold-down mechanism includes an engagement arm positioned to receive an actuation force from a corresponding cam surface in the image forming device and move toward the developer unit to apply a hold-down force on the developer unit in response to receiving the actuation force from the corresponding cam surface in the image forming device when the toner container is inserted into the image forming device with the developer unit installed in the image forming device.
Embodiments include those wherein the engagement arm is translatable upward toward a top of the body and downward toward a bottom of the body. In some embodiments, a biasing member biases the engagement arm upward. In some embodiments, the engagement arm includes a lower end that extends downward past a bottom of the body upon the engagement arm receiving the actuation force.
The accompanying drawings incorporated in and forming a part of the specification, illustrate several aspects of the present disclosure, and together with the description serve to explain the principles of the present disclosure.
In the following description, reference is made to the accompanying drawings where like numerals represent like elements. The embodiments are described in sufficient detail to enable those skilled in the art to practice the present disclosure. It is to be understood that other embodiments may be utilized and that process, electrical, and mechanical changes, etc., may be made without departing from the scope of the present disclosure. Examples merely typify possible variations. Portions and features of some embodiments may be included in or substituted for those of others. The following description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined only by the appended claims and their equivalents.
Image forming device 20 includes an image transfer section that includes one or more imaging stations 50. Each imaging station 50 includes a toner cartridge 100, a developer unit 200 and a photoconductor unit (PC unit) 80. Each toner cartridge 100 includes a reservoir 102 for holding toner and an outlet port in communication with an inlet port of a corresponding developer unit 200 for transferring toner from reservoir 102 to developer unit 200. In the example embodiment illustrated, developer unit 200 utilizes what is commonly referred to as a single component development system. In this embodiment, each developer unit 200 includes a toner reservoir 202 and a toner adder roll 204 that moves toner from reservoir 202 to a developer roll 206. Each PC unit 80 includes a charging roll 82 and a photoconductive (PC) drum 84 for each imaging station 50. PC drums 84 are mounted substantially parallel to each other. For purposes of clarity, developer unit 200 and PC unit 80 are labeled on only one of the imaging stations 50 in
Each charging roll 82 forms a nip with the corresponding PC drum 84. During a print operation, charging roll 82 charges the outer surface of PC drum 84 to a specified voltage. A laser beam from a printhead 52 associated with each imaging station 50 is then directed to the outer surface of PC drum 84 and selectively discharges those areas it contacts to form a latent image. Developer roll 206 then transfers toner to PC drum 84 to form a toner image. A metering device, such as a doctor blade 209, may be used to meter toner on the outer surface of developer roll 206 and apply a desired charge to the toner prior to its transfer to PC drum 84. Toner on developer roll 206, which forms a nip 86 with PC drum 84, is attracted to the areas of the outer surface of PC drum 84 discharged by the laser beam from printhead 52.
In the example embodiment illustrated, an intermediate transfer mechanism (ITM) 54 is disposed adjacent to imaging stations 50. In this embodiment, ITM 54 is formed as an endless belt trained about a drive roll 56, a tension roll 58 and a back-up roll 60. During print operations, ITM 54 moves past imaging stations 50 in a counterclockwise direction as viewed in
The media sheet with the toner image is then moved along the media path 32 and into a fuser area 68. Fuser area 68 includes fusing rolls or belts 70 that form a nip 72 to adhere the toner image to the media sheet. The fused media sheet then passes through transport rolls 74 located downstream from fuser area 68, which move the media sheet to an output area 76 of image forming device 20 or to duplex path 36 for image formation on a second side of the media sheet, as desired.
A monocolor image forming device 20 may include a single imaging station 50, as compared to a color image forming device 20, which may include multiple imaging stations 50.
In the example embodiment illustrated, each positioning slot 406 includes a respective latch 300 that secures a corresponding developer unit 200 in imaging basket 400. Latch 300 is positioned at a front end 408 of the positioning slot 406 proximate to one end of the corresponding developer unit 200. In the example embodiment illustrated, each latch 300 is manually movable between a latched position (see
In the example embodiment illustrated, each end 214, 215 of body 210 includes a respective end cap 223, 224 mounted on a corresponding end wall at each end 214, 215, such as by suitable fasteners (e.g., screws, rivets, etc.) or by a snap-fit engagement. In this embodiment, the end walls at ends 214, 215 along with top 212, bottom 213 and sides 216, 217 form toner reservoir 202. A drive coupler (not shown) is exposed on an outer portion of first end 214 in position to receive rotational force from a corresponding drive system in image forming device 20 when developer unit 200 is installed in image forming device 20 to drive rotatable components of developer unit 200 including, for example, toner adder roll 204 and developer roll 206, to rotate toner adder roll 204 and developer roll 206 upon receiving rotational force from the corresponding drive system in image forming device 20. The drive system in image forming device 20 may include one or more drive motors and a drive transmission from the drive motor(s) to a drive coupler that mates with the drive coupler of developer unit 200 when developer unit 200 is installed in image forming device 20.
Developer unit 200 includes a plunger 250 positioned at second end 215 of developer unit 200. In the embodiment illustrated, plunger 250 includes a plunger head 252 that projects upward from end cap 224 to receive a downward hold-down force from another feature or component of image forming device 20 for securing developer unit 200 in imaging basket 400, as discussed below. Plunger 250 is biased by a biasing member 256 to provide a reaction force against the hold-down force applied to plunger 250. In the example embodiment illustrated, biasing member 256 includes a compression spring; however, any suitable biasing member may be used as desired, such as, for example, an extension spring, a torsion spring, a leaf spring or a material having resilient properties. In the example embodiment illustrated, plunger 250 is translatable vertically, along a biasing direction of biasing member 256; however, plunger 250 may be directly or indirectly biased according to any suitable method as desired.
In the example embodiment illustrated, hold-down 320 on latch 300 is positioned to engage plunger 250 in such a way that substantially no moment force on latch 300 along the direction of rotational motion of latch 300 between the latched position and the unlatched position is generated when latch 300 is in the latched position. For example, hold-down 320 is positioned on latch 300 such that hold-down 320 at distal end 306 of neck portion 304 and a pivot boss 308 positioned about pivot axis 302 are aligned along the length of neck portion 304. In this manner, hold-down 320 can apply a linear force F in a direction towards pivot axis 302 when a force is applied against engagement surface 324 of hold-down 320 in the opposite direction, such as when plunger 250 engages hold-down 320 from below when hold-down 320 is in the latched position, as discussed below.
In the example embodiment illustrated, handle 340 is positioned at distal end 306 of neck portion 304 opposite pivot boss 308 and is oriented at an angle from, such as perpendicular to, neck portion 304. In one example embodiment, handle 340 is positioned to provide a moment arm to introduce a moment force for facilitating release of latch 300 from the latched position. For example, in the embodiment illustrated, handle 340 is positioned on latch 300 at a location that is offset from pivot boss 308 and hold-down 320 relative to neck portion 304 to create a lever arm relative to pivot boss 308. In this manner, when handle 340 is operated by a user, the force applied to handle 340 by the user can generate a moment about pivot boss 308 due to the perpendicular distance between the line of action of the applied force and the pivot point to aid in the release of latch 300.
When latch 300 is in the unlatched position, hold-down 320 is rotated in a direction away from plunger 250 such that hold-down 320 is positioned clear of the installation path of developer unit 200 allowing developer unit 200 to be vertically removed from or installed in a corresponding positioning slot 406 of imaging basket 400. In the embodiment illustrated in
In one example embodiment, the clearance between latch 300 and developer unit 200 when latch 300 is in the unlatched position is greater than the clearance between other surfaces adjacent to developer unit 200 such that no impedance or obstruction to the removal or installation of developer unit 200 may be caused by latch 300. For example, in the embodiment shown in
When latch 300 is in the latched position, hold-down 320 of latch 300 depresses plunger 250 on developer unit 200 and applies a downward hold-down force to plunger 250 as shown in
In the example embodiment illustrated, contact between hold-down 320 of latch 300 and spring-biased plunger 250 on developer unit 200 results in a downward hold-down force on plunger 250 that aids in keeping most of the hold-down force from directly acting on body 210 of developer unit 200. As a result, the net load applied to developer unit 200 by latch 300 is reduced. In addition, the use of plunger 250 prevents unwanted forces, such as impacts and vibrations, from being directly transmitted to developer unit 200. For example, biasing member 256 may compress or extend to absorb and reduce the effects of movements or vibrations on developer unit 200.
To release latch 300 from the latched position to the unlatched position, a user-applied force is used to lift handle 340 to generate torque (due to the moment arm which is the perpendicular distance from pivot axis 302 to the line of action of the user-applied force) causing latch 300 to rotate away from plunger 250. When hold-down 320 of latch 300 initially rotates away from plunger 250, plunger 250 also pushes back hold-down 320 due to the spring force of biasing member 256 until hold-down 320 disengages from plunger 250. Latch 300 is rotated to its final unlatched position when latch 300 rotationally stops upon tab 346 on arm 342 of latch 300 engaging the corresponding portion on front end 408 of imaging basket 400 as shown in
The above example embodiments provide a more stable hold-down force of developer unit 200 in comparison with assemblies that include hold downs applied to the developer unit 200 by the toner cartridge since the reaction force is not against a positionally compliant supply item remote from the developer unit within the image forming device beyond the imaging basket, such as the toner cartridge. In addition, there is no residual vertical hold-down force pushing toner cartridge 100 upward in an undesirable manner, which would interfere with aesthetics, tactile feedback during installation, and proper functioning of toner cartridge 100. Further, the example embodiments permit developer units 200 to be easily dropped straight down and lifted out of their corresponding positioning slots 406 in imaging basket 400 with ample clearance by latches 300 folding out of the developer unit installation path, further than neighboring surfaces of imaging basket 400 or adjacent developer units 200. The example embodiments also achieve a more uniform hold down force regardless of part manufacturing, assembly and module placement tolerances within image forming device 20 because of the spring-biased plunger 250 on developer unit 200.
In the above example embodiments, latch 300 on imaging basket 400 is used to depress plunger 250 on developer unit 200 in order to hold-down and secure second end 215 of developer unit 200 against corresponding datums in imaging basket 400. In other embodiments, plunger 250 on developer unit 200 may be depressed by other features or components in image forming device 20 to hold down developer unit 200. For example, toner cartridge 100 may include one or more features for engaging plunger 250 of developer unit 200 to hold-down second end 215 of developer unit 200 against imaging basket 400.
In the embodiment illustrated, toner cartridge 100 includes a hold-down mechanism 150 positioned on side 109 of body 104. Hold-down mechanism 150 includes an engagement arm 154 for applying a hold-down force on plunger 250 of developer unit 200 when toner cartridge 100 is inserted into image forming device 20. In the embodiment illustrated, engagement arm 154 has an upper end surface 155 for receiving a force for driving engagement arm 154 downward and a lower end surface 156 forming a wedge for engaging plunger 250 on developer unit 200 when engagement arm 154 is driven downward upon upper end surface 155 receiving a downward force. In the embodiment illustrated, lower end surface 156 of engagement arm 154 is tapered upward from a bottom end of engagement arm 154 in a direction toward first end 107 of toner cartridge 100. Lower end surface 156 is unobstructed such that lower end surface 156 contacts plunger 250 positioned along the insertion path of lower end surface 156 when toner cartridge 100 is inserted into image forming device 20, as discussed below. A sleeve 152 retains engagement arm 154 on side 109 of body 104 and supports the sliding motion of engagement arm 154 in directions C, D between an engaged position and a disengaged position relative to plunger 250. In the example embodiment illustrated, engagement arm 154 is in the disengaged position when engagement arm 154 is in a raised position, disengaged from plunger 250 and is in the engaged position when engagement arm 154 is in a lowered positioned to contact plunger 250.
Engagement arm 154 is biased in an upward, bottom-to-top direction D, such as by one or more springs, such that engagement arm 154 is biased toward the disengaged position. In the embodiment illustrated, an extension spring 158 is connected between a first spring mount 157 on engagement arm 154 and a second spring mount 160 on side 109 of body 104 to continuously bias engagement arm 154 in bottom-to-top direction D. First spring mount 157 on engagement arm 154 contacts an upward stop 162 on sleeve 152 when engagement arm 154 is in the disengaged position. The biasing force of spring 158 is overcome when engagement arm 154 moves downward in top-to-bottom direction C when upper end surface 155 of engagement arm 154 receives a downward force from a feature or corresponding surface in image forming device 20 causing engagement arm 154 to move from the disengaged position to the engaged position.
In the embodiment illustrated, upper end surface 155 of engagement arm 154 is unobstructed such that upper end surface 155 contacts a feature positioned along the insertion path of upper end surface 155 in order for engagement arm 154 to move from the disengaged position to the engaged position during insertion of toner cartridge 100 into image forming device 20. In one example embodiment, upper end surface 155 of engagement arm 154 is positioned to contact a cam 185 disposed above a toner cartridge compartment 190 for receiving toner cartridge 100, as shown in
In the example embodiment illustrated, cam 185 is positioned along the path of insertion of upper end surface 155 of engagement arm 154 of hold-down mechanism 150 to provide an actuation force to engagement arm 154 to move engagement arm 154 from the disengaged position to the engaged position against the biasing force of spring 158 during insertion of toner cartridge 100 into image forming device 20. In the embodiment illustrated, cam 185 includes a ramped section 187 and a dwell 189. Upper end surface 155 of engagement arm 154 is configured to travel along ramped section 187 as engagement arm 154 transitions between the disengaged position and the engaged position, as discussed below. To reduce frictional resistance between contact points, engagement arm 154 and cam 185 may be made from materials having relatively small coefficients of friction.
It will be appreciated that engagement arm 154, the mounting configuration of engagement arm 154 on body 104, and cam 185 above toner cartridge 100 illustrated are intended to serve as examples and that one or more components of hold-down mechanism 150 or cam 185 may be mounted according to any suitable configuration that permits engagement arm 154 to move between the disengaged and engaged positions. For example, sleeve 152 is shown as a separate element that is attached to body 104 in the example illustrated, but sleeve 152 may be formed as part of body 104. In another example, cam 185 is formed as part of insertion guide 180 in the example illustrated, but cam 185 may be an attached stand-alone part or a drawn area of a horizontal frame plate above toner cartridge compartment 190.
When toner cartridge 100 is removed from image forming device 20, the above sequence is reversed. The biasing force applied by spring 158 pulls engagement arm 154 of hold-down mechanism 150 towards the disengaged position as toner cartridge 100 moves from the position shown in
The example embodiments shown in
In some embodiments, if a user needs to replace a developer unit 200 in imaging basket 400, there is no need for the user to manually release developer unit 200 for removal or to reactivate the hold down force after installation of developer unit 200 since all that is needed to remove or reactivate the hold down force on developer unit 200 is for the user to remove or install toner cartridge 100. This ensures ease of use and reliability, eliminating the need for users to figure out removal and installation steps nor risk omitting steps or performing the steps in an incorrect sequence.
Although the example image forming device 20 discussed above includes four toner cartridges 100 and corresponding developer units 200 and PC units 80, more or fewer replaceable units may be used depending on the color options needed. For example, in one embodiment, the image forming device includes a single toner cartridge and corresponding developer unit and PC unit in order to permit monochrome printing.
The foregoing description illustrates various aspects of the present disclosure. It is not intended to be exhaustive. Rather, it is chosen to illustrate the principles of the present disclosure and its practical application to enable one of ordinary skill in the art to utilize the present disclosure, including its various modifications that naturally follow. All modifications and variations are contemplated within the scope of the present disclosure as determined by the appended claims. Relatively apparent modifications include combining one or more features of various embodiments with features of other embodiments.
This application claims priority to U.S. Provisional Patent Application Ser. No. 63/621,775, filed Jan. 17, 2024, entitled “Hold Down Assembly for a Developer Unit of an Image Forming Device” and to U.S. Provisional Patent Application Ser. No. 63/621,778, filed Jan. 17, 2024, entitled “Hold Down Assembly for a Developer Unit of an Image Forming Device,” the contents of which are hereby incorporated by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63621778 | Jan 2024 | US | |
| 63621775 | Jan 2024 | US |
