Knockdown for compiling recording media in finisher

A knockdown apparatus for a finisher includes a register tray, a paddle coupled to a rotatable shaft to compile a recording medium toward an end of the register tray, and a knockdown device, provided above the register tray, to rotate to apply a downward force to the recording medium while the recording medium is in the register tray to decrease a curl in the recording medium.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is filed under 35 U.S.C. § 371 as a National Stage of PCT International Application No. PCT/US2018/032282, filed on May 11, 2018, in the U.S. Patent and Trademark Office, the disclosure of which is incorporated by reference herein in its entirety.

BACKGROUND

A finisher refers to an apparatus for processing a recording medium, such as paper, supplied from an image forming apparatus. The finisher can be connected to the image forming apparatus to receive the recording medium during a job, and is in communication with the image forming apparatus. For example, the finisher may perform a stapling operation, an alignment operation, and/or a folding operation with respect to the recording medium supplied from the image forming apparatus.

An image forming apparatus refers to an apparatus that forms images on a recording medium according to inputted signals. Examples of an image forming apparatus include a printer, a copy machine, a scanner, a facsimile, and a multi-function peripheral device that combines and implements various functions of the printer, copy machine, scanner, and/or facsimile. Examples of a printer include an inkjet printer or a laser printer.

DETAILED DESCRIPTION

Before a recording medium is compiled and a finishing operation is performed on the recording medium by a finisher, an image forming apparatus may perform a conditioning process on the recording medium. For example, the conditioning process may remove water, smooth the recording medium, or a combination thereof. The conditioning process may be more difficult when there is a significant amount of ink placed on the recording medium. To remove the water from the recording medium, a temperature of a heated pressure roller within the image forming apparatus may be raised, however the increase temperature can result in a curled or “smiling” recording medium.

When the curled “smiling” recording medium is transported to a compiler area of the finisher, the curled “smiling” recording medium can fill the compiler area. The compiler area may include paddles to pull a recording medium toward an end portion of a registration tray for a finishing operation to be performed on the recording medium. However, because the recording medium is curled, this may prevent the paddles from pulling the recording medium toward the end portion of the registration tray. Thus, a finishing operation may have poor compiling of recording media, the finishing operation may be poorly performed on the recording media, and a size of a stack of recording media for which the finishing operation is to be performed on may be limited.

According to various examples of the disclosure, a finisher includes a knockdown apparatus which knocks down a recording medium during the compiling process of the recording medium so as to flatten the recording medium and eliminate or decrease the curl. Because the curl can be decreased or eliminated, a job quality of compiled media stacks may be improved, increased temperatures may be utilized in the image forming apparatus to remove moisture from a recording medium, and a stack capacity may be increased.

Various examples of the disclosure will now be described with reference to the accompanying drawings, wherein like reference characters denote like elements. Examples to be explained in the following may be modified and implemented in various different forms.

When it is stated in the disclosure that one element is “connected to” or “coupled to” another element, the expression encompasses not only an example of a direct connection or direct coupling, but also a connection with another element interposed therebetween. Further, when it is stated herein that one element “includes” another element, unless otherwise stated explicitly, it means that yet another element may be further included rather than being excluded.

FIG.1is a schematic structural diagram of an image forming apparatus and finisher400according to an example. Referring toFIG.1, the image forming apparatus includes a printer100and a scanner300coupled to a finisher400.

The printer100prints an image on a sheet-type medium, which may also be referred to as a recording medium, provided from a paper feeder. The paper feeder may be, for example, a main cassette feeder210installed under the printer100, or secondary cassette feeders220and230installed under the main cassette feeder210. Although not illustrated, the paper feeder may further include a multi-purpose tray (MPT), a high capacity feeder installed at a side of the printer100, or a combination thereof.

The printer100may also include a control panel130to receive an input from a user to control the image forming apparatus, for example to perform a function of the image forming apparatus. The control panel130may include a keyboard, a button, a display, or combinations thereof for the user to operate the image forming apparatus. The display may be a touchscreen to receive the input from the user.

The printer100may print an image on a recording medium by using various printing methods such as an electrophotography method, an inkjet method, a thermal transfer method, and a thermal sublimation method. For example, the image forming apparatus may print a color image on the recording medium by using an inkjet method. The printer100may be a S path-type of printer or a C path-type of printer, for example.

The scanner300reads an image recorded on a document. The scanner300may have any of various structures such as a flatbed mechanism where a document is at a fixed position and an image is read while a reading member is moved, a document feeding mechanism where a reading member is at a fixed position and a document is fed, and a combination structure thereof.

The finisher400may include a sheet folding device (not illustrated) for folding, one or more times, the recording medium discharged from the printer100. The finisher400may further include an alignment device (not illustrated) for aligning the recording medium discharged from the printer100. The alignment device may have a structure for stapling the recording medium at an end portion thereof or punching a hole in an end portion of the recording medium. The finisher400may further include a stapler for stapling the paper at a center portion thereof. Other example processes or functions the finisher400may perform include hole punching, binding, embossing, gluing, coating, varnishing, foil stamping, texturing, lamination, cutting, creasing, stacking, binding, splicing, rewinding, or combinations thereof.

FIG.2is a block diagram of the printer100, the finisher400, and an external device700, according to an example. InFIG.2, the printer100includes controller110and machine readable storage120, the finisher400includes controller410and machine readable storage420, and the external device includes controller710and machine readable storage720. The finisher400also includes a driving source430and a sensor440which will be discussed in more detail below. The driving source430may include a motor, solenoid, other electromechanical devices, or combinations thereof. The sensor440may include a position sensor that senses a position of a recording medium on a path in the finisher, a weight sensor, a proximity sensor, a light sensor, or combinations thereof.

The finisher400may include a controller410and machine readable storage420. The controller410may execute instructions stored in the machine readable storage420. The printer100may also include a controller110and machine readable storage120. The finisher400, the printer100, and the external device700may be connected with one another in a wired and/or wireless manner such that the finisher400, printer100, and external device700can communicate with one another to exchange information, including job information regarding an image forming job performed or to be performed by the image forming apparatus including the printer100and scanner300, a finishing job performed or to be performed by the finisher400, or combinations thereof.

The controllers110,410,710may include, for example, a processor, an arithmetic logic unit, a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), an image processor, a microcomputer, a field programmable array, a programmable logic unit, an application-specific integrated circuit (ASIC), a microprocessor, or combinations thereof.

The machine readable storages120,420,720may be any electronic, magnetic, optical, or other physical storage device that stores executable instructions. For example, the machine readable storages120,420,720may include a nonvolatile memory device, such as a Read Only Memory (ROM), Programmable Read Only Memory (PROM), Erasable Programmable Read Only Memory (EPROM), and flash memory, a USB drive, a volatile memory device such as a Random Access Memory (RAM), a hard disk, floppy disks, a blue-ray disk, or optical media such as CD ROM discs and DVDs, or combinations thereof.

The external device700may include a personal computer, a laptop, a tablet, a smartphone, a server, or combinations thereof. The external device700may be used to control the finisher400, the printer100, or combinations thereof. For example, the external device700may receive an input from a user regarding a job or function of the finisher400, the printer100, or combinations thereof. The external device700may include a user interface730to receive the input and a display740to display information regarding the finisher400and the printer100. The user interface730may include, for example, a keyboard, a mouse, a joystick, a button, a switch, an electronic pen or stylus, a gesture recognition sensor, an input sound device or voice recognition sensor such as a microphone, an output sound device such as a speaker, a track ball, a remote control, a touchscreen, or combinations thereof. The external device700may also include a display740.

FIGS.3A-3Bare schematic cross-sectional views of the finisher according to an example.

Example paths traveled on by the recording medium in the finisher400will now be described. The recording medium is received by the finisher400from the printer100at an input port451. Depending on the design of the finisher400and the processes to be performed on the recording medium, there may be numerous paths that the recording medium may be transported on before being output to an output bin. For example, as illustrated inFIG.3A, a diverter452may divert the recording medium to an upper path453or a lower path454for the recording medium to be output to an upper output bin455or a lower output bin456. Various rollers and other devices may contact and handle a recording medium within the finisher400. The rollers and other devices may be driven by various motors, solenoids, and other electromechanical devices, which can be controlled via the controller410of the finisher400, the controller110of the printer100, or a controller located elsewhere, or by a combination thereof.

As illustrated inFIG.3A, the finisher400includes an upper output bin455and a lower output bin456. The upper output bin455may be utilized for simple jobs in which a finishing process or collated stacking is not performed. For example, a recording medium may be transported along the upper path453to be output to the upper output bin455when a stapling operation is not performed on the recording medium. The lower output bin456may be utilized for jobs for which a stacking or stapling operation is performed. For example, a recording medium may be transported along the lower path to be output to the lower output bin456when a stapling operation is performed on the recording medium. The lower output bin456may be movable. For example, the lower output bin456may be lowered or raised. The lower output bin456may be lowered or raised depending on a number of recording media that are held by the lower output bin456.

When a finishing process is to be performed with respect to a recording medium and the recording medium is transported along the lower path454, the recording medium may be transported to a section of the finisher400referred to as a compiler500. The compiler500may include a stapler510to staple the recording medium to another recording medium or to recording media before the stapled media is ejected or discharged from the compiler500and output to the lower output bin456. The compiler500may also include a register tray520, a pusher bar550and a tamper560(seeFIG.5), to be described in more detail below.

FIG.4Ais a perspective view illustrating a plurality of paddle units530coupled to a rotatable shaft540according to an example.FIG.4Bis a side view illustrating a driving source coupled to a rotatable shaft according to an example. The compiler500may include the paddle units530coupled to the rotatable shaft540as shown inFIG.4A.

As illustrated inFIG.4Aeach of the paddle units530includes a plurality of paddles531. The plurality of paddle units530coupled to the rotatable shaft540may be located at spaced apart intervals along the rotatable shaft540in an axial direction of the rotatable shaft540. The plurality of paddles531can be at spaced apart intervals, circumferentially about the respective paddle unit530. Each of the paddles531extends in a radial direction outward from the paddle unit530and rotatable shaft540. For example, there may be three paddle units530coupled to the rotatable shaft540. Each of the paddle units530may include two paddles531at spaced apart intervals, circumferentially about the respective paddle unit530. However, the disclosure is not so limited and there may be more than three paddle units530or less than three paddle units530. Furthermore, there may be more than two paddles531on a respective paddle unit530, or less than two paddles531. For example, there could be a single paddle unit530coupled to the rotatable shaft540where the paddle unit530has a single paddle531. The paddle531may be made of polyurethane. However, the paddle531may be made of another material. For example, the material of the paddle531may be selected based on frictional characteristics. For example, the material of the paddle531may be selected so that the recording medium may be pulled back to the end portion521of the register tray520efficiently. As shown inFIG.4A, the paddle531may have a substantially rectangular shape.

The driving source430may include a motor, a solenoid, another electromechanical device, or combinations thereof. For example, as illustrated inFIG.4Bthe driving source430may include a motor431, a gear432coupled to the rotatable shaft540, and a driving belt433coupling the motor431to the gear432to drive rotation of the rotatable shaft540according to a signal output from the controller410. The rotatable shaft540may be rotated in a first direction and a second direction by the driving source430. The first direction may be referred to as a “forward” direction and the second direction may be referred to as a “reverse” direction. The first direction may be a clockwise direction and the second direction a counterclockwise direction. Or the first direction may be a counterclockwise direction and the second direction a clockwise direction. The paddles531rotate together with the rotation of the rotatable shaft540. Because the paddles531are coupled to the rotatable shaft540, when the rotatable shaft540is rotated in the forward direction, the paddles531rotate together with the rotatable shaft540in the forward direction. When the paddles531are rotated in the forward direction during a compiling operation, the paddles531compile a recording medium in a direction toward an end portion521of the register tray520so that the recording media, which are stacked on top of one another, are aligned at the end portion521of the register tray520and can be stapled together by the stapler510in a defined manner. As a number of recording media accommodated in the register tray520increases, a height of the compiled stack of recording media also increases.

An example path along which the recording medium travels to the compiler500will now be described with respect toFIG.1. For example, with reference toFIGS.3A and3Bthe recording medium may pass through a pair of exit rollers457and drop down to the register tray520. An exit roller sensor441located at or near the exit rollers457can detect a position of the recording medium. The exit roller sensor441may also be referred to as position sensor441. The sensor440can include the exit roller sensor441. For example, the exit roller sensor441can detect when the recording medium arrives at the exit rollers457, passes through the exit rollers457to the register tray520, or a combination thereof. The exit roller sensor441may send a signal to the controller410indicating a position of the recording medium. For example, the signal may indicate the recording medium has arrived at the exit rollers457or has passed through the exit rollers457to the register tray520. In this way the controller410can determine how many recording media are accommodated in the register tray520during a finishing operation. For example, the controller410can include a counter to count or index the number of recording media that have arrived at the exit rollers457or passed through the exit rollers457during the finishing operation.

As the recording medium drops down from the exit rollers457to the register tray520the pusher bar550may rotate to push downward against a trailing edge of the recording medium to assist the recording medium in dropping down to the register tray520. When the recording medium is located on the register tray520the rotatable shaft540and paddles531may rotate in the forward direction. For example, during the compiling of the recording medium, the controller410may transmit a signal to the driving source430to control the driving source430to rotate the rotatable shaft540in the forward direction. Also, when the recording medium is located on the register tray520the tamper560may be moved in an inward direction toward opposite sides of the recording media to align the stacked recording media in a widthwise direction of the recording medium. The tamper560may be moved in the inward direction toward opposite sides of the recording media a plurality of times to align the stacked recording media in the widthwise direction.

FIG.5is a perspective view of a knockdown device800coupled to an upper paper guide570of the compiler500according to an example.FIG.6is a side view of the knockdown device800coupled to the upper paper guide570of the compiler500according to an example. The compiler500includes a knockdown device800to knock down a recording medium during the compiling process of the recording medium so as to flatten the recording medium and eliminate or decrease a curl in the recording medium. As shown inFIG.6, a body of the knockdown device800includes one end coupled to a pin571installed in the upper paper guide570such that the knockdown device800is rotatable about the pin571similar to a hinge. The pin571can be provided in a groove or slot572of the upper paper guide570. As another example, the pin571may be provided on an end of the knockdown device800as a rotatable knockdown shaft of the knockdown device800, and inserted into the groove or slot572of the upper paper guide570. The upper paper guide570may be mounted inside a main body of the finisher. For example, the upper paper guide570may be mounted or coupled to a frame of the finisher. Two knockdown devices800can be coupled to the upper paper guide570, for example. For example, the knockdown devices800can be positioned to knockdown the recording medium on opposite sides of the recording medium in the widthwise direction. For example, each knockdown device800can extend outward from the upper paper guide570at a location between a tamper560and a paddle531coupled to the rotatable shaft540. The knockdown device800may be located at a position spaced apart from the tamper560such that the tamper560does not strike the knockdown device800when the tamper560moves inward to align the sides of the recording media stacked in the registration tray during compiling of the recording media. In another example to be further described below, the tamper560may contact the knockdown device. For example, when the tamper560moves inward the tamper560may slide under the knockdown device800and cause the knockdown device800to rotate upward. When the tamper560moves outward the knockdown device800then rotates back downward by the force of gravity.

As shown inFIG.6, the knockdown device800is rotatable about the pin571to rotate between a resting or lower position P1and an upper position P3. An intermediate position P2is also shown inFIG.6. In the resting position P1, the knockdown device800may be spaced apart from the register tray520in a vertical direction. An angle of the knockdown device800in the resting position P1, for example relative to a plane perpendicular to a rotation axis of the pin571, or a height of above the registration tray520, may be set according to a force to be applied to the recording medium in the downward direction and the pulling force of the paddles531which pull the recording medium toward the end portion of the register tray520. If the register tray520contains recording media, depending on a height of the stack of recording media, in the resting position P1the knockdown device800may rest on an upper surface of a top recording medium of the stack of recording media, or the knockdown device800may be spaced apart from the upper surface of the top recording medium of the stack of recording media.

When the knockdown device800is in the resting position P1and a recording medium is transported from the exit rollers457to the register tray520in the compiler500, the recording medium may be partially ejected in an outward direction toward the lower output bin456, before being pulled back in toward the end portion521of the register tray520by the paddles531of the compiler500. When the recording medium is partially ejected in the outward direction toward the lower output bin456, a leading edge of the recording medium contacts inner sides of the knockdown devices800and causes the knockdown devices800to rotate upward. An amount of rotation of the knockdown devices800in the upward direction may be depend on various factors including the force applied to the knockdown devices800by the recording medium according to the speed of travel of the recording medium, a weight of the recording medium, a weight of the knockdown device800, or combinations thereof, for example. After the knockdown devices800swing upward, the knockdown devices800then rotate downward by a force of gravity to apply a downward force on an upper surface of the recording medium. The knockdown devices800may apply the downward force on the upper surface of the recording medium as the recording medium is being pulled back toward the end portion of the register tray520. Therefore, the knockdown device800can reduce a curl in the recording medium when in the resting position and also by applying a downward force when the knockdown device800rotates downward and contacts the upper surface of the recording medium.

The knockdown device can have various shapes. For example, the knockdown device may have a substantially rectangular shape as shown by the knockdown device800′ illustrated inFIG.8. As another example, as illustrated inFIGS.7A-7B, the knockdown device800may have a first portion800A that extends at one end outward from the upper paper guide570, a second portion800B that has one end bent downward from the other end of the first portion800A, and a third portion800C that has one end bent upward from the other end of the second portion800B.

A width of the knockdown device in the widthwise direction may also be varied. For example, a wider width of the knockdown device800′ compared to the knockdown device800in the widthwise direction may allow the knockdown device800to contact a greater area of the recording medium and to contact different types of recording media with narrower widths.

A weight of the knockdown device along a direction perpendicular to the widthwise direction and an axial direction of the rotatable shaft may also be varied. For example, a first end of the knockdown device, opposite of a second end of the knockdown device coupled to the upper paper guide570, may have a greater weight compared to the second end of the knockdown device coupled to the upper paper guide. The greater weight of the first end of the knockdown device may allow a greater downward force to be applied to the recording medium.

FIGS.7A-7Bare enlarged views of the tamper560and knockdown device800according to an example. As mentioned above, in an example the tamper560may contact the knockdown device. For example, as shown inFIGS.7A and7B, when the tamper560moves inward the tamper560may engage ramps820on an outer side of the knockdown device800to lift the knockdown device800out of the way. The ramps820may extend from the second end of the knockdown device800in an inward direction such that the knockdown device800is tapered, with the second end of the knockdown device800being wider than the first end of the knockdown device800in the widthwise direction. The tamper560slides under the knockdown device800and causes the knockdown device800to rotate upward. When the tamper560moves outward the knockdown device800then rotates back downward. Because the knockdown device800can be lifted by the tamper560, the knockdown device800may be located further outward and closer to the tamper560.

FIG.8is perspective view of knockdown device800′ according to an example. As shown inFIG.8, the first end of the knockdown device800′, opposite of the second end of the knockdown device800′ coupled to the upper paper guide570, may include roller wheels810. The roller wheels810can reduce a friction force between the knockdown device800′ and the upper surface of the recording medium. The reduced friction force may allow the paddles571to more easily pull the recording medium toward the end portion521of the register tray520. As shown inFIG.8, the first end of the knockdown device800′ has two roller wheels810. However, a single roller wheel or more than two roller wheels may be provided at the first end of the knockdown device. Although not shown, the knockdown device800illustrated inFIGS.5to7Bmay also include roller wheels810at the first end of the knockdown device800.

Accordingly, the rotatable knockdown devices800and800′ shown inFIGS.5through8can knock down the recording medium during the compiling process of the recording medium so as to flatten the recording medium and eliminate or decrease a curl in the recording medium.

FIG.9is a perspective view of a knockdown device900in an upper position and coupled to an upper paper guide570of the compiler500, according to an example.FIG.10is a side view of the knockdown device900in a lower position, according to an example.FIG.11is another view of the knockdown device900coupled to the upper paper guide570of the compiler500according to an example. The knockdown900includes a body901that is elongated in a direction perpendicular to a rotation axis of the rotatable shaft540. A length of the body901may be chosen in consideration of a range of widths of recording mediums that may be processed by the finisher400balanced with avoiding contacting with the tamper560during the compiling operation, for example. InFIG.9, one end of each of the arms902a,902bextends from the body and the other end of each of the arms902a,902bis coupled to the upper paper guide570.

The knockdown device900is mounted to the upper paper guide570. For example, each arm902a,902bis coupled to the upper paper guide570by a rotatable knockdown shaft904a,904bthat is formed as a protrusion or pin which protrudes from an outer side of each of the arms902a,902b. The rotatable knockdown shafts904a,904bare inserted into a groove or pinhole572that is formed in a portion of the upper paper guide570. The knockdown device900is rotatable about the rotatable knockdown shafts904a,904b, such that a rotation axis of the knockdown device900is parallel to and offset from a rotation axis of the rotatable shaft540.

The upper paper guide570may include a cutout or recess573formed therein to accommodate the arms902a,902band body901of the knockdown device900when the knockdown device900is in an upper position. The ability to store the knockdown device900in the recess573while the knockdown device900is not being utilized allows the knockdown device900to avoid contact with a recording medium being compiled as well as recording media stacked in the register tray520. Also, a sound-dampening material may be provided in the recess573so that when the knockdown device900returns to the upper position, a noise may be reduced or minimized. A sound-dampening material can also be provided on an upper side of the knockdown device900. The sound-dampening material may include an acoustic foam, for example.

To retain the knockdown device900in the upper position, an elastic member907may be coupled between a hook574formed in the upper paper guide570and a receptacle905provided in an end portion or tab906aof arm902aof the knockdown device900, as shown inFIG.14according to an example. The arm902bof the knockdown device900also includes an end portion or tab906b. The elastic member907may be an extension spring for example.

A plurality of ribs903may be formed on a lower surface of the knockdown device900. The ribs903protrude from the lower surface of the knockdown device900such that when the knockdown device900contacts the recording medium a surface area of the knockdown device900that contacts the recording medium is less than a surface area of the knockdown device900that contacts the recording medium when no ribs are provided. Therefore, a noise level caused by the knockdown device900striking the recording medium can be reduced. The knockdown device900may be made of plastic, for example.

The knockdown device900may include surfaces which are chamfered, curbed, or angled in such a way to reduce a noise associated with rotating the knockdown in an upward and downward motion. For example, the body901, the arms902a,902b, the ribs903, or a combination thereof, may have curved surfaces.

FIG.12is a view illustrating cams541a,541bin contact with tabs906a,906bof the knockdown device900, according to an example. The knockdown device900can be rotated by rotation of the cams541a,541bwhich are coupled to the rotatable shaft540. The interaction between the cams541a,541band knockdown device900may be similar to a see-saw mechanism. As illustrated inFIG.12, an upper side of the cams541a,541bmay contact a lower side of tab906a,906bof the knockdown device900. When the cams541a,541bare rotated in a counter-clockwise direction, the tabs906a,906bare moved upward and the opposite side of the knockdown device900which includes the body901and arms902a,902bis moved downward. As illustrated inFIGS.13and14, the cams541a,541bmay be interlocked with tabs906a,906bof the knockdown device900, according to an example. However, as illustrated inFIG.12, the cams541a,541bmay be located near or abut the tabs906a,906bof the knockdown device900without being interlocked, according to an example.

FIGS.13and14are views illustrating the rotatable shaft540and cams541a,541bfrom a rear side of the upper paper guide570. As shown inFIG.14, a one-way clutch542may be coupled to the rotatable shaft540to control rotation of a corresponding cam such that the cams rotate in one direction but do not rotate in the other direction. For example, a one-way clutch542may be provided for each of the cams541a,541b. A one-way clutch542may be incorporated for each cam541a,541bon the rotatable shaft540such that when the rotatable shaft540and paddles531rotate in the forward direction to pull the recording medium back toward the end portion521of the register tray520, the cams541a,541bdo not rotate, and when the rotatable shaft540and paddles531rotate in the reverse direction, the cams541a,541bare rotated via the corresponding one-way clutch542to actuate the tabs906a,906bof the knockdown device900and cause the knockdown device900to rotate downward and contact the recording medium to apply a downward force to the recording medium. According to another example, the one-way clutch542may instead be a friction clutch.

An operation of the knockdown device900will now be described according to an example. When the recording medium drops down from the exit rollers457to the register tray520the pusher bar550may rotate to push downward against a trailing edge of the recording medium to assist the recording medium in dropping down to the register tray520. When the recording medium is located on the register tray520the rotatable shaft540and paddles531may rotate in the forward direction. The rotatable shaft540and paddles531may rotate in the forward direction once or a plurality of times. For example, during the compiling of the recording medium, the controller410may transmit a signal to the driving source430to control the driving source430to rotate the rotatable shaft540in the forward direction a predetermined number of times. The driving source430may be a motor, for example. The signal or command indicates to the driving source430the number of times the rotatable shaft540is to be rotated by the driving source430in the forward direction during a compiling operation with respect to the recording medium. A number of rotations of the rotatable shaft540in the forward direction for compiling a recording medium can vary. For example, the controller410can determine the number of rotations of the rotatable shaft540in the forward direction based on information regarding the recording medium, information regarding the finishing operation, or combinations thereof.

Information regarding the recording medium and finishing operation may be obtained from the printer100, the finisher400itself, from another source, or combinations thereof. As an example, when a job is received at the printer100, the printer100may communicate with the finisher400by transmitting a signal including job information to the finisher400that identifies, or is indicative of, various characteristics pertaining to the job. For example, the job information may include a number of recording media to be compiled, a type of recording medium, a thickness of the recording medium, an ink content on the recording medium, or combinations thereof. The job information may be in the form of a code. The controller410of the finisher400can interpret the job information received from the printer100, for example by interpreting the code, to obtain the job information. The controller410can store the job information in the machine readable storage420.

According to an example, because the one-way clutch542prevents rotation of the cams541a,541bduring forward rotation of the rotatable shaft540, the cams541a,541bdo not rotate, and the knockdown device900is not rotated, when the rotatable shaft540is rotated in the forward direction.

After completion of the forward rotation of the rotatable shaft540and paddles531, the rotatable shaft540may be rotated in a reverse direction. For example, the controller410may transmit a signal to the driving source430to control the driving source430to rotate the rotatable shaft540in the reverse direction a predetermined number of times. According to an example, because the one-way clutch542permits rotation of the cams541a,541bduring reverse rotation of the rotatable shaft540, the cams541a,541brotate and the knockdown device900is rotated downward to contact the recording medium. For example, the knockdown device900may contact the leading edge or front portion of the recording medium. The cams541a,541bare rotated a same number of times the rotatable shaft540is rotated in the reverse direction. The knockdown device900performs the knockdown action a same number of times the rotatable shaft540is rotated in the reverse direction. The number of reverse rotations of the rotatable shaft540may be once or a plurality of times. The number of reverse rotations of the rotatable shaft540may be less than the number of times the rotatable shaft540and paddles531are rotated in the forward direction for paddling the recording medium. As another example, the controller410may determine no reverse rotation of the rotatable shaft540is to be performed. For example, the controller410may determine, based on a type of recording medium for example, that the recording medium is unlikely to have a curl and therefore the knockdown is not performed by the knockdown device900.

Actuation of the knockdown device900is based on the rotation of the rotatable shaft540to drive the motion of the knockdown device900, for example. The cams541a,541bare coupled to the rotatable shaft540through a one-way clutch or friction clutch so as to control the timing of the knockdown actuation. The knockdown device900can be activated such that rotation of the rotatable shaft540in the reverse direction causes the knockdown device900to lower once per cycle. According to this operation, actuation of the knockdown device900is performed independent of a number of forward paddles performed to compile media. As another example, rotation of the knockdown device900may be based on the rotation of the rotatable knockdown shafts904a,904b, which may be combined as a single shaft, to drive the motion of the knockdown device900. That is, a driving source, other than a driving source used to drive rotatable shaft540, may be provided to drive rotation of the rotatable knockdown shaft and the knockdown device900.

The knockdown device900is rotated to contact the recording medium and may be immediately rotated back upwards to the upper position to be stored in the recess573of the upper paper guide570. The knockdown device900may be lowered for a duration long enough to contact the recording medium and eliminate or reduce the curl in the recording medium, while also not delaying completion of the compiling and finishing operations unnecessarily. Also, because the knockdown actuation occurs during a reverse rotation of the rotatable shaft540, interference between the knockdown device900and operation of the tamper560and paddles531may be avoided.

FIG.15is a perspective view of a knockdown device900′ in an upper position and coupled to the upper paper guide570′ of the compiler500, according to an example.FIG.16is a side view of the knockdown device900′, according to an example.FIGS.17A and17Bare side views of the knockdown device900′ in the upper position and a lower position, respectively, according to an example. The knockdown device900′ includes a body901′ that is elongated in a direction perpendicular to a rotation axis of the rotatable shaft540. A length of the body901′ may be chosen in consideration of a range of widths of recording mediums that may be processed by the finisher400balanced with avoiding contacting with the tamper560during the compiling operation, for example. As shown inFIGS.15and16, one end of each of the arms902a′,902b′ extends from the body901′ and the other end of each of the arms902a′,902b′ is coupled to the upper paper guide570′.

The knockdown device900′ is mounted to the upper paper guide570′. For example, each arm902a′,902b′ is coupled to the upper paper guide570′ by a rotatable knockdown shaft904a′,904b′ that is formed as a protrusion or pin which protrudes from an outer side of each of the arms902a′,902b′. The rotatable knockdown shafts904a′,904b′ are inserted into a respective groove or pinhole572′ that is formed in a portion of the upper paper guide570′. The knockdown device900′ is rotatable about the rotatable knockdown shafts904a′,904b′, such that a rotation axis of the knockdown device900′ is parallel to and offset from a rotation axis of the rotatable shaft540. As can be seen fromFIG.16, the rotation axis of the knockdown device900′ is on an opposite side of the rotatable shaft compared to the rotation axis of the knockdown device900inFIG.12.

The upper paper guide570′ may include a cutout or recess573′ formed therein to accommodate the arms902a′,902b′, and body901′ of the knockdown device900′ when the knockdown device900′ is in an upper position. The ability to store the knockdown device900′ in the recess573′ while the knockdown device900′ is not being utilized allows the knockdown device900′ to avoid contact with a recording medium being compiled as well as recording media stacked in the register tray520. Also, a sound-dampening material may be provided in the recess573′ so that when the knockdown device900′ returns to the upper position, a noise may be reduced or minimized. A sound-dampening material can also be provided on an upper side of the knockdown device900′.

A plurality of ribs903′ may be formed on a lower surface of the knockdown device900′. The ribs903′ protrude from the lower surface of the knockdown device900′ such that when the knockdown device900′ contacts the recording medium a surface area of the knockdown device900′ that contacts the recording medium is less than a surface area of the knockdown device900′ that contacts the recording medium when no ribs are provided. Therefore, a noise level caused by the knockdown device900′ striking the recording medium can be reduced. The knockdown device900′ may be made of plastic, for example.

The knockdown device900′ may include surfaces which are chamfered, curbed, or angled in such a way to reduce a noise associated with rotating the knockdown in an upward and downward motion. For example, the body901′, arms902a′,902b′, ribs903′, or a combination thereof, may have curved surfaces.

As shown inFIGS.15through17B, the end of the arms902a′,902b′ connected to the upper paper guide570′ may have various shapes. For example, the end of the arms902a′,902b′ connected to the upper paper guide570′ may have a closed rectangular or box shaped handle, an L-shaped handle, or a U-shape handle. In each of the examples ofFIGS.15through17B, cams541a′,541b′ are disposed at an inner side of the handles, such that an upper surface of the cams541a′,541b′ is in contact with an inner side surface of the corresponding handle.

FIGS.17A and17Bare side views of the knockdown device900′ in the upper position and a lower position, respectively, according to an example.FIGS.17A and17Bshow cam541a′ in contact with inner side surface909′ of handle908′ provided at the end of arm902a′ of the knockdown device900′, according to an example. The knockdown device900′ can be rotated by rotation of the cams541a′,541b′ which are coupled to the rotatable shaft540. As illustrated inFIG.17A, when the cam541a′ is in an upper position, the knockdown device900′ is in an upper position. As illustrated inFIG.17B, when the cam541a′ rotates to a lower position, due to a force applied by the cam541a′ to the inner side of the handle908′, the knockdown device900′ rotates downward to contact the recording medium. The cam541a′ completes its rotation to return to the highest position and the knockdown device900′ returns to the upper position.

An operation of the knockdown device900′ will now be described according to an example. When the recording medium is located on the register tray520the rotatable shaft540and paddles531may rotate in the forward direction. The rotatable shaft540and paddles531may rotate in the forward direction once or a plurality of times. The number of forward rotations may depend on a type of recording medium, an amount of ink on the recording medium, or a combination thereof, for example. For example, during the compiling of the recording medium, the controller410may transmit a signal to the driving source430to control the driving source430to rotate the rotatable shaft540in the forward direction a predetermined number of times.

The cams541a′,541b′ rotate together with rotation of the rotatable shaft540. Therefore, the cams541a′,541b′ rotate a same number of times that the rotatable shaft540is rotated and a same number of times that the paddles rotate. Furthermore, because the knockdown device900′ is actuated when the cams541a′,541b′ rotate, the knockdown device900′ performs the knockdown of the recording medium a same number of times that the rotatable shaft540rotates. For example, if the paddles are rotated in the forward direction two times to compile a recording medium, the knockdown device900′ is actuated two times by the cams541a′,541b′ such that the knockdown device900′ is rotated and two knockdowns of the recording medium are performed. Likewise, if the paddles are rotated in the forward direction four times to compile a recording medium, four knockdowns of the recording medium are performed. For example, the knockdown device900′ may contact the leading edge or front portion of the recording medium.

As another example, the controller410may determine no forward rotation of the rotatable shaft540is to be performed. For example, the controller410may determine, based on a type of recording medium for example, that the recording medium is unlikely to have a curl and therefore paddling by the paddles531and a knockdown by the knockdown device900′ is not performed.

Actuation of the knockdown device900′ is based on the rotation of the rotatable shaft540to drive the motion of the knockdown device900′. The cams541a′,541b′ are coupled to the rotatable shaft540so as to control the timing of the knockdown actuation. The knockdown device900′ can be activated such that rotation of the rotatable shaft540in the forward direction causes the knockdown device900′ to rotate downward to apply a force to the recording medium once per cycle or once each rotation of the rotatable shaft540. According to this operation, actuation of the knockdown device900′ is dependent upon the number of forward paddles performed to compile media. For example, a number of times the knockdown device900′ is actuated and the number of forward paddles performed to compile media may be the same such that there is a 1 to 1 relationship between the number of times the knockdown device900′ is actuated and the number of forward paddles performed to compile media.

As another example, rotation of the knockdown device900′ in the forward direction may be based on the rotation of the rotatable knockdown shafts904a′,904b′, which may be combined as a single shaft, to drive the motion of the knockdown device900′. That is, a driving source, other than a driving source used to drive rotatable shaft540, may be provided to drive rotation of the rotatable knockdown shaft and the knockdown device900′.

The knockdown device900′ is rotated to contact the recording medium and may be immediately rotated back upwards to the upper position to be stored in the recess573′ of the upper paper guide570′. The knockdown device900′ may be lowered for a duration long enough to contact the recording medium and eliminate or reduce the curl in the recording medium, while also not delaying completion of the compiling and finishing operations unnecessarily. For example, for compiling of a recording medium during a single rotation of the rotatable shaft540, the knockdown device900′ may be in contact with the recording medium for a duration less than a duration that the paddles531are in contact with the recording medium. Minimizing or reducing a duration that the knockdown device900′ is lowered also reduces a risk of the knockdown device900′ interfering with operation of the tamper560and paddles531during compiling.

FIG.18is a perspective view of a knockdown device900″ in an upper position and coupled to the upper paper guide570″ of the compiler500, according to an example. The knockdown device900″ differs from the knockdown device900′ in that the two arms are not joined together by a common body, resulting in two L-shaped knockdowns. As shown inFIG.18, the knockdown device900″ includes a first body901a″ and a second body901b″ that are each elongated in a direction perpendicular to a rotation axis of the rotatable shaft540. A length of the first body901a″ and the second body901b″ and a distance that the first body901a″ and the second body901b″ are spaced apart from one another may be chosen in consideration of a range of widths of recording mediums that may be processed by the finisher400balanced with avoiding contacting with the tamper560during the compiling operation, for example. One end of first arm902a″ extends from the first body901″ and the other end of first arm902a″ is coupled to the upper paper guide570″. Likewise, one end of second arm902b″ extends from the second body901″ and the other end of second arm902b″ is coupled to the upper paper guide570″.

The knockdown device900″ may be mounted to the upper paper guide570″ in a manner similar to that described above with respect to knockdown device900′. That is, except for the fact that arms902a″,902b″ are not joined together by a common body in contrast to the knockdown device900′, the knockdown device900″ may be considered to be similar in construction and operation in all other respects compared to knockdown device900′ and therefore a detailed description thereof will not be repeated. However, because arms902a′,902b′ of knockdown device900′ are joined together by the common body903′, the arms902a′,902b′ of knockdown device900′ may experience less torsion or twisting compared to the arms902a″,902b″ of knockdown device900″ during rotation.

After the knockdown device completes the knockdown action on the recording medium, and the recording media have been compiled in the register tray520, a finishing process can be performed on the recording media and the finished recording media can be discharged or ejected from the compiler500to the lower output bin456for retrieval by a user. For example, the stapler510(seeFIG.3A) can perform a stapling operation on the recording media when the recording media has been compiled. The stapled recording media can be ejected or discharged from the compiler500to the lower output bin456. For example, the stack of finished recording media can be ejected or discharged from the compiler500using a clamp that clamps an edge of the stack of finished recording media, ejector arms, a conveying belt580(seeFIG.5), and wheel590(seeFIG.5) that transport the stack of finished recording media out to the lower output bin456.

As discussed above, various knockdown devices for a finisher may be implemented to knock down a recording medium during a compiling process of the recording medium so as to flatten the recording medium and eliminate or decrease a curl in the recording medium. Reduction of the curl can improve a job quality of compiled media stacks, enable increased temperatures to be utilized in the image forming apparatus to remove moisture from a recording medium, and increase a stack capacity of the compiler in the finisher.

Executable instructions to perform processes or operations in accordance with the above-described examples may be recorded in a machine readable storage. A controller may execute the executable instructions to perform the processes or operations. Examples of instructions include both machine code, such as that produced by a compiler, and files containing higher level code that may be executed by the controller using an interpreter. The instructions may be executed by a processor or a plurality of processors included in the controller. The machine readable storage may be distributed among computer systems connected through a network and computer-readable codes or instructions may be stored and executed in a decentralized manner.

The foregoing examples are merely examples and are not to be construed as limiting the disclosure. The disclosure can be readily applied to other types of apparatuses. Also, the description of the examples of the disclosure is intended to be illustrative, and not to limit the scope of the claims.