Patent Description:
In image forming apparatuses as an example of conveyance apparatuses, an operation of detecting the presence of a remaining sheet in the conveyance apparatus and prompting a user to remove the remaining sheet is widely known as an initialization process before printing is performed. For example, when an image forming apparatus transfers ink onto the sheet, the image forming apparatus grips a leading end of a sheet as a print medium with a holder called a gripper and brings the sheet into close contact with a cylindrical drum to perform printing while conveying the sheet. In such an image forming apparatus, an entrance rotator (entrance drum), an image forming conveyance drum, and an exit rotator (exit drum), which serve as an image forming unit, convey the sheet while the gripper grips the leading end of the sheet. When the gripper of the exit drum releases the leading end of the sheet at a delivery position, the sheet is conveyed downstream to a fixing device for drying the sheet.

Further, a technology is known in which, for example, a drive system in an image forming apparatus is moved for a predetermined period of time as a method for detecting and removing a remaining sheet in an initialization process. When a remaining sheet is present on a drum surface of an image forming device provided for the image forming apparatus, it is not possible to detect the remaining sheet on the drum surface simply by attaching a reflective photosensor or a transmissive photosensor to the drum surface. This is because it is not possible to determine whether light emitted from the photosensor is blocked by the drum surface or by the remaining sheet. Also, it is not possible to install a photosensor by making a hole in the drum surface. This is because the sheet is attracted and adhered to the drum surface by air suction to keep the gap between the sheet and a liquid discharge unit at a constant distance. For this reason, when a hole is made in the drum surface for the photosensor, the sheet may not be attracted and adhered to the drum surface favorably at the position of the hole.

Further, when an image forming device and a fixing device are controlled independently in such an image forming apparatus, for example, an initialization process for each of the image forming device and the fixing device is also executed independently. In this case, depending on the timing of each initialization process, a driving source of the fixing device may stop before the remaining sheet on the drum surface of the image forming device can be sufficiently conveyed to the fixing device. Accordingly, the remaining sheet may not be detected.

As such an image forming apparatus, an image forming apparatus disclosed in <CIT> includes a conveyance device for conveying a print medium, an ink fixing device, a detector for detecting a conveyance failure, and a controller for reducing a recovery time from the conveyance failure. Further, an image forming apparatus disclosed in <CIT> includes a body, an optional sheet ejection device, a controller, and a control unit for ejecting remaining sheets remaining inside the image forming apparatus while reducing peak power consumption at the time of power-on of the image forming apparatus. <CIT> discloses an inkjet recording apparatus that includes a jam detection method using two output signals output from two detection sensors to detect the abnormal pass of the print medium.

However, in technologies known in the art, there is a problem that a remaining sheet on a drum surface may not be reliably ejected, for example, in an initialization process.

In light of the above-described problem, an object of the present disclosure is to provide a conveyance apparatus capable of reliably ejecting a remaining sheet when there is a sheet remaining on a drum surface.

According to an embodiment of the present disclosure, a conveyance apparatus includes a bearing rotator, an entrance rotator, an exit rotator, a first driver, a downstream conveyor, a second driver, and a recording medium detector. The bearing rotator rotates, while bearing a recording medium, to convey the recording medium. The entrance rotator receives, at a first position, the recording medium fed from upstream in a recording medium conveyance direction and delivers the recording medium to the bearing rotator while rotating to convey the recording medium. The exit rotator receives the recording medium conveyed by rotation of the bearing rotator and delivers the recording medium at a second position downstream in the recording medium conveyance direction while rotating to convey the recording medium. The first driver rotates the bearing rotator, the entrance rotator, and the exit rotator. The downstream conveyor receives, at the second position, the recording medium conveyed by rotation of the exit rotator and conveys the recording medium downstream in the recording medium conveyance direction. The second driver drives the downstream conveyor for conveyance. The recording medium detector detects the recording medium on a conveyance path on which the recording medium is conveyed by the downstream conveyor. As a process of removing the recording medium remaining on at least one of the bearing rotator, the entrance rotator, and the exit rotator, the first driver starts rotation operation after the second driver starts driving the downstream conveyor for conveyance, and rotates the bearing rotator, the entrance rotator, and the exit rotator for a period of time equal to or longer than a period of time taken for the recording medium to be conveyed from the first position to the second position. The second driver continues driving the downstream conveyor for conveyance for a period of time equal to or longer than a period of time taken for the recording medium to be conveyed from the second position to a position at which the recording medium is detected by the recording medium detector after the rotation operation of the first driver is stopped.

According to another embodiment of the present disclosure, an image forming apparatus includes the conveyance apparatus.

According to the present disclosure, when there is a sheet remaining on the drum surface, the remaining sheet can be reliably ejected.

The accompanying drawings are intended to depict embodiments of the present invention and should not be interpreted to limit the scope thereof, which is defined in the appended claims.

Hereinafter, a conveyance apparatus according to embodiments of the present disclosure is described in detail with reference to the drawings. The present disclosure is not limited by the following embodiments, and the components and elements in the following embodiments include those that can be easily conceived from the components and elements by those skilled in the art, substantially the same components and elements, and so-called equivalent ranges of components and elements.

<FIG> is a diagram illustrating an overall configuration of an image forming apparatus <NUM> according to an embodiment of the present disclosure. <FIG> is a diagram illustrating a configuration of an image forming device <NUM> provided for the image forming apparatus <NUM>, according to the present embodiment. The overall configuration of the image forming apparatus <NUM> according to the present embodiment is described with reference to <FIG> and <FIG>.

The image forming apparatus <NUM> illustrated in <FIG> forms an image on a fed sheet by an inkjet method using a line head and then ejects the sheet as an example of a conveyance apparatus. As illustrated in <FIG>, the image forming apparatus <NUM> includes a sheet carry-in device <NUM>, a printer <NUM>, and a sheet carry-out device <NUM>.

The sheet carry-in device <NUM> is a device that carries in a sheet P as a sheet-shaped print medium as an example of recording medium. As illustrated in <FIG>, the sheet carry-in device <NUM> includes a lower carry-in tray 11a and an upper carry-in tray 11b that accommodate multiple sheets P, a sheet feeding device 12a that separates sheets P one by one from the lower carry-in tray 11a and feeding out the sheets P, and a sheet feeding device 12b that separates the sheets P one by one from the upper carry-in tray 11b and feeds out the sheet P. The sheet carry-in device <NUM> feeds the sheet P fed out by the sheet feeding device 12a and the sheet feeding device 12b to the image forming device <NUM>. Note that, for example, a pretreatment device that applies coating liquid such as pretreatment liquid to the sheet P may be disposed between the sheet carry-in device <NUM> and the printer <NUM>.

The printer <NUM> is a device that discharges ink onto the sheet P supplied from the sheet carry-in device <NUM> by an inkjet method using a line head to form an image. As illustrated in <FIG>, the printer <NUM> includes an image forming device <NUM>, a fixing device <NUM>, a duplex mechanism <NUM>, a controller <NUM>, and a display <NUM> as an example of a notification device.

In the image forming device <NUM>, a liquid discharger <NUM> discharges the ink onto the sheet P, which is supplied from the sheet carry-in device <NUM> and conveyed on a carry-in path <NUM> by a conveyance roller pair <NUM>, to form an image on the sheet P. As illustrated in <FIG>, the image forming device <NUM> includes a drum <NUM> as a bearing rotator, the liquid discharger <NUM>, an entrance rotator <NUM>, and an exit rotator <NUM>.

The drum <NUM> includes grippers <NUM> that serve as grippers. The drum <NUM> is a rotator that conveys the sheet P by rotation operation while gripping a leading end of the sheet P fed from the entrance rotator <NUM> with one of the grippers <NUM>. A plurality of suction holes are formed on a peripheral surface of the drum <NUM> in a dispersed manner, and suction air flows are generated from the plurality of suction holes inward of the drum <NUM> by a suction device. Thus, the sheet P is attracted and borne on the peripheral surface of the drum <NUM>.

The liquid discharger <NUM> discharges ink onto the sheet P conveyed by the rotation operation of the drum <NUM> to form an image on the sheet P. The liquid discharger <NUM> includes a liquid discharge unit 32C for discharging cyan (C) ink, a liquid discharge unit <NUM> for discharging magenta (M) ink, a liquid discharge unit 32Y for discharging yellow (Y) ink, and a liquid discharge unit <NUM> for discharging black (K) ink. Note that the color of the ink is not limited to cyan, magenta, yellow, and black, and the liquid discharger <NUM> may include a liquid discharge unit for discharging special ink such as white ink, gold ink, silver ink or fluorescent ink.

The discharge operation of the liquid discharger <NUM> is controlled by drive signals corresponding to print data. When the sheet P borne on the drum <NUM> passes through a region of the peripheral surface of the drum <NUM> facing the liquid discharger <NUM>, ink of each color is discharged from the liquid discharger <NUM>. Thus, an image corresponding to the print data is formed and printed on the sheet P. The sheet P on which the image has been formed is conveyed from the drum <NUM> to the exit rotator <NUM>.

The entrance rotator <NUM> receives the sheet P, which is fed from upstream in a recording medium conveyance direction, at a receiving position A, i.e., a first position and transfers the sheet P between the drum <NUM> and the entrance rotator <NUM>. A gripper <NUM> that serves as a gripper is disposed on an outer peripheral region of the entrance rotator <NUM>. The sheet P conveyed on the carry-in path <NUM> by the conveyance roller pair <NUM> is gripped by the gripper <NUM> at the receiving position A, and the sheet P is conveyed to the drum <NUM> by the rotation operation of the entrance rotator <NUM>. A leading end of the sheet P is gripped by the gripper <NUM> and the sheet P is conveyed along with the rotation of the entrance rotator <NUM> and is delivered to the drum <NUM> at a position at which the entrance rotator <NUM> and the drum <NUM> face each other.

The exit rotator <NUM> receives the sheet P conveyed by the rotation of the drum <NUM> and delivers the sheet P to the fixing device <NUM> at a delivery position B, i.e., a second position. A gripper <NUM> that serves as a gripper is disposed on an outer peripheral region of the exit rotator <NUM>. The sheet P conveyed by the rotation of the drum <NUM> is held by the gripper <NUM> and the sheet P is conveyed to a conveyance belt <NUM> of the fixing device <NUM> by the rotation operation of the exit rotator <NUM>. The gripper <NUM> moves around in synchronization so as to match the position of any one of the grippers <NUM> of the drum <NUM>. Accordingly, the leading end of the sheet P can be delivered to the fixing device <NUM>. Note that the exit rotator <NUM> may be coupled to the entrance rotator <NUM> via gears and rotate in conjunction with the entrance rotator <NUM>.

The fixing device <NUM> dries and fixes ink on the sheet P on which an image has been formed by the image forming device <NUM>. Accordingly, liquid such as water in the ink on the sheet P evaporates and colorant contained in the ink is fixed on the sheet P. Thus, the curl of the sheet P is reduced. As illustrated in <FIG>, the fixing device <NUM> includes the conveyance belt <NUM> as a downstream conveyor, a heater <NUM>, a sheet detection sensor <NUM> as a recording medium detector, and a suction device <NUM>.

The conveyance belt <NUM> is an endless belt stretched between a drive roller <NUM> and a driven roller <NUM> and conveys the sheet P received from the exit rotator <NUM>. When the conveyance belt <NUM> conveys the sheet P, the conveyance belt <NUM> conveys the sheet P downstream in the recording medium conveyance direction such that the sheet P passes through the heater <NUM> at a predetermined conveyance speed. The conveyance speed of the sheet P conveyed by the conveyance belt <NUM> is set by the rotation speed of the drive roller <NUM>. The rotation speed of the drive roller <NUM> is controlled by the controller <NUM>. When the leading end of the sheet P is separated from the exit rotator <NUM> and transferred to the conveyance belt <NUM>, the rotation speed of the drive roller <NUM> is adjusted so that the conveyance belt <NUM> operates at the predetermined conveyance speed. Further, a plurality of suction holes are formed in a dispersed manner on a surface of the conveyance belt <NUM>, and the sheet P is attracted and borne on the conveyance belt <NUM> by suction air flows from the suction device <NUM>.

The heater <NUM> heats the sheet P conveyed by the conveyance belt <NUM>. The heater <NUM> heats the sheet P to dry and fix the ink on the sheet P.

The sheet detection sensor <NUM> detects the sheet P that has been transferred from the exit rotator <NUM> to the conveyance belt <NUM> at the delivery position B and conveyed to the fixing device <NUM>.

The suction device <NUM> generates the suction air flows that are sucked through the multiple suction holes formed on the surface of the conveyance belt <NUM> by a suction operation and causes the sheet P to be attracted to the conveyance belt <NUM>.

The sheet P that has passed through the fixing device <NUM> is conveyed by the rotation of a conveyance roller pair <NUM> through an ejection path <NUM> and is sent to the duplex mechanism <NUM> or the sheet carry-out device <NUM>.

When both sides of the sheet P are to be printed, the duplex mechanism <NUM> reverses the sheet P that has passed through the fixing device <NUM> and feeds the sheet P again upstream from the image forming device <NUM> in the recording medium conveyance direction, i.e., to the carry-in path <NUM>. As illustrated in <FIG>, the duplex mechanism <NUM> includes a reverse path <NUM> and a duplex path <NUM>.

The reverse path <NUM> is a path on which the sheet P that has passed through the fixing device <NUM> is received and reversed by the rotation of the conveyance roller pair <NUM>.

The duplex path <NUM> is a path on which the sheet P that has been reversed by the reverse path <NUM> is conveyed upstream from the image forming device <NUM> in the recording medium conveyance direction by the rotation of the conveyance roller pair <NUM> and the sheet P is fed again to the carry-in path <NUM>.

The controller <NUM> controls the operation of the entire image forming apparatus <NUM>. The controller <NUM> controls, for example, an image forming operation of the image forming device <NUM>, a drying operation of the fixing device <NUM>, and a conveyance operation of various conveyance paths. Note that the sheet carry-in device <NUM> or the sheet carry-out device <NUM> may be controlled by another controller different from the controller <NUM>.

The display <NUM> displays various data such as an operation state of the image forming apparatus <NUM>, print setting data, and a job state. The display <NUM> may include a touch screen that achieves not only a display function but, for example, a touch input function.

The sheet carry-out device <NUM> stores the sheets P conveyed from the printer <NUM>. The sheet carry-out device <NUM> includes an output tray <NUM> on which multiple sheets P are stacked. Each of the sheets P conveyed from the printer <NUM> is sequentially stacked and held on the output tray <NUM>.

<FIG> is a block diagram illustrating a hardware configuration of the controller <NUM> of the image forming apparatus <NUM>, according to the present embodiment. The hardware configuration of the controller <NUM> of the image forming apparatus <NUM> according to the present embodiment is described with reference to <FIG>.

As illustrated in <FIG>, the controller <NUM> includes a central processing unit (CPU) <NUM>, a read only memory (ROM) <NUM>, a random access memory (RAM) <NUM>, an external interface (I/F) <NUM>, a head drive control circuit <NUM>, a rotation drive circuit <NUM> serving as a first driver, a conveyance drive circuit <NUM> serving as a second driver, a heating drive circuit <NUM>, a suction drive circuit <NUM>, a sensor I/F <NUM>, and a conveyance drive circuit <NUM>. The above-described units and devices can communicate with each other via a bus line.

The CPU <NUM>, as an arithmetic unit, reads various programs stored in the ROM <NUM> and reads the programs into the RAM <NUM> used as a work area to achieve various functions.

The external I/F <NUM> is an interface for communicating with a host <NUM> that is an external device connected via a network such as a local area network (LAN) or a wide area network (WAN) constructed by a data transmission path such as a wired path or a wireless path. The host <NUM> is, for example, a data processing apparatus such as a digital front end (DFE).

The head drive control circuit <NUM> drives and controls the discharge operation of the liquid discharger <NUM> of the printer <NUM> based on image data in accordance with a command from the CPU <NUM>.

The rotation drive circuit <NUM> drives and controls the rotation operation of the drum <NUM>, the entrance rotator <NUM>, and the exit rotator <NUM> of the image forming device <NUM> in accordance with commands from the CPU <NUM>. Note that the entrance rotator <NUM> and the exit rotator <NUM> may be coupled so as to rotate in accordance with the rotation of the drum <NUM>. In such a case, the rotation drive circuit <NUM> may drive and control the rotation of the drum <NUM>.

The conveyance drive circuit <NUM> drives and controls the rotation of the drive roller <NUM> of the fixing device <NUM> in accordance with a command from the CPU <NUM> to convey the sheet P on the conveyance belt <NUM>.

The heating drive circuit <NUM> drives and controls heating operation of the heater <NUM> of the fixing device <NUM> in accordance with a command from the CPU <NUM>.

The suction drive circuit <NUM> drives and controls the suction operation of the suction device <NUM> of the fixing device <NUM> in accordance with a command from the CPU <NUM>.

The sensor I/F <NUM> receives detection data detected by various sensors such as the sheet detection sensor <NUM> disposed in the image forming apparatus <NUM>.

The conveyance drive circuit <NUM> drives and controls rotation operations of various rollers such as the conveyance roller pair <NUM>, the conveyance roller pair <NUM>, the conveyance roller pair <NUM>, and the conveyance roller pair <NUM> in accordance with commands from the CPU <NUM>.

Note that the hardware configuration of the controller <NUM> illustrated in <FIG> is an example, and other components may be included in the controller <NUM>. For example, in addition to components illustrated in <FIG>, the controller <NUM> may include a non-volatile RAM (NVRAM) which is a nonvolatile memory, an application specific integrated circuit (ASIC) for executing image processing, or a field-programmable gate array (FPGA) for performing input and output signal processing.

<FIG> is a functional block diagram illustrating a configuration of the controller <NUM> of the image forming apparatus <NUM>, according to the present embodiment. With reference to <FIG>, the configuration and operation of functional blocks of the controller <NUM> of the image forming apparatus <NUM> according to the present embodiment is described.

As illustrated in <FIG>, the controller <NUM> of the image forming apparatus <NUM> includes a first drive controller <NUM>, a second drive controller <NUM>, a detector <NUM>, a suction controller <NUM>, and a display controller <NUM>.

The first drive controller <NUM> controls the rotation of the drum <NUM>, the entrance rotator <NUM>, and the exit rotator <NUM> of the image forming device <NUM> via the rotation drive circuit <NUM> to convey the sheet P. The CPU <NUM> illustrated in <FIG> executes a program to implement the first drive controller <NUM>.

The second drive controller <NUM> controls the rotation of the drive roller <NUM> via the conveyance drive circuit <NUM> to convey the sheet P on the conveyance belt <NUM>. The CPU <NUM> illustrated in <FIG> executes a program to implement the second drive controller <NUM>.

The detector <NUM> detects the sheet P, which has been transferred from the exit rotator <NUM> to the conveyance belt <NUM> and conveyed to the fixing device <NUM>, based on a detection signal that is received by the sensor I/F <NUM> from the sheet detection sensor <NUM> for detecting the sheet P. The CPU <NUM> illustrated in <FIG> executes a program to implement the detector <NUM>.

The suction controller <NUM> controls the suction operation of the suction device <NUM> via the suction drive circuit <NUM> to attract the sheet P to the conveyance belt <NUM>. The suction controller <NUM> can control the suction force of the suction device <NUM> in multiple stages. The CPU <NUM> illustrated in <FIG> executes a program to implement the suction controller <NUM>.

The display controller <NUM> controls the display operation of the display <NUM>. The CPU <NUM> illustrated in <FIG> executes a program to implement the display controller <NUM>.

Note that a part or all of the first drive controller <NUM>, the second drive controller <NUM>, the detector <NUM>, the suction controller <NUM>, and the display controller <NUM> may be implemented by an integrated circuit such as an FPGA or an ASIC, instead of a software program.

Each of the above-described functional units of the controller <NUM> illustrated in <FIG> conceptually represents a corresponding function. However, the controller <NUM> is not limited to such a configuration. For example, multiple functional units as independent functional units of the controller <NUM> illustrated in <FIG> may be one functional unit. Alternatively, functions of one functional unit of the controller <NUM> illustrated in <FIG> may be divided into multiple functional units that may function as the multiple functional units.

<FIG> is a diagram illustrating the image forming device <NUM> in a state in which a remaining sheet is present in the image forming device <NUM>, according to the present embodiment. <FIG> is a diagram illustrating the image forming device <NUM> in a state in which a remaining sheet is conveyed from the image forming device <NUM> to the fixing device <NUM> in the image forming apparatus <NUM>, according to the present embodiment. An outline of a process of removing a remaining sheet from the image forming device <NUM> of the image forming apparatus <NUM> according to the present embodiment is described with reference to <FIG> and <FIG>.

When printing processing in the image forming apparatus <NUM> is terminated or an emergency stop is performed due to a printing failure, as illustrated in <FIG>, a sheet P may be present in the image forming device <NUM> as a remaining sheet. Note that as the case where a sheet P is present as a remaining sheet in the image forming device <NUM>, <FIG> illustrates a state in which the sheet P is gripped by the gripper <NUM>. However, the case where the sheet P is present as a remaining sheet in the image forming device <NUM> is not limited to such a state. For example, the sheet P may be gripped by the gripper <NUM> of the entrance rotator <NUM> or the gripper <NUM> of the exit rotator <NUM>.

When the sheet P is present as the remaining sheet in the image forming device <NUM> as described above, the sheet P as the remaining sheet in the image forming device <NUM> is removed as an initialization process before the printer <NUM> performs a next printing processing. In the present embodiment, the initialization process refers to a predetermined process performed by the printer <NUM> to normally perform the printing processing before the printer <NUM> performs the print processing. The initialization process includes, for example, the processing of removing the remaining sheet in the image forming device <NUM> described above.

As illustrated in <FIG>, when the sheet P is present as the remaining sheet in the image forming device <NUM>, the first drive controller <NUM> controls the rotation operation of the drum <NUM>, the entrance rotator <NUM>, and the exit rotator <NUM> and the second drive controller <NUM> controls the conveyance operation of the conveyance belt <NUM> in a cooperative manner to convey the sheet P as the remaining sheet to a position at which the sheet P is detected by the sheet detection sensor <NUM> of the fixing device <NUM> as illustrated in <FIG>. A cooperative operation by the first drive controller <NUM> and the second drive controller <NUM> is described in detail in the following description.

<FIG> is a timing chart illustrating how the image forming device <NUM> and the fixing device <NUM> of the image forming apparatus <NUM> are driven for conveyance, according to the present embodiment. <FIG> is a timing chart illustrating how the image forming device <NUM> and the fixing device <NUM> of the image forming apparatus <NUM> are driven for conveyance, in a case in which a remaining sheet is ejected in a minimum time in the image forming apparatus <NUM>, according to the present embodiment. <FIG> is a timing chart illustrating how the image forming device <NUM> and the fixing device <NUM> of the image forming apparatus <NUM> are driven for conveyance, in a case in which a remaining sheet is detected in the image forming apparatus <NUM>, according to the present embodiment. A timing chart that illustrates how the image forming device <NUM> and the fixing device <NUM> are driven to convey a remaining sheet in the initialization process of the image forming apparatus <NUM> is described with reference to <FIG>, and <FIG>.

First, as illustrated in <FIG>, at a time T0, the second drive controller <NUM> of the controller <NUM> controls the rotation operation of the drive roller <NUM> via the conveyance drive circuit <NUM> to drive the conveyance belt <NUM> for conveyance. In the following description, when the second drive controller <NUM> controls the rotation of the drive roller <NUM> via the conveyance drive circuit <NUM> to drive the conveyance belt <NUM> for conveyance, such an operation may be simply referred to as "driving the fixing device <NUM> for conveyance".

Next, at a time T1 equal to or greater than the time T0, the first drive controller <NUM> of the controller <NUM> controls the rotation operation of the drum <NUM>, the entrance rotator <NUM>, and the exit rotator <NUM> of the image forming device <NUM> via the rotation drive circuit <NUM> to drive the image forming device <NUM> for conveyance. In the following description, when the first drive controller <NUM> controls the rotation operation of the drum <NUM>, the entrance rotator <NUM>, and the exit rotator <NUM> of the image forming device <NUM> via the rotation drive circuit <NUM> to drive the conveyance belt <NUM>, such an operation may be simply referred to as "driving the image forming device <NUM> for conveyance".

As described above, after the time T1, the second drive controller <NUM> drives the fixing device <NUM> for conveyance and the first drive controller <NUM> drives the image forming device <NUM> for conveyance. Accordingly, the sheet P present as the remaining sheet in the image forming device <NUM> is conveyed from the image forming device <NUM> toward the fixing device <NUM>.

Next, the first drive controller <NUM> stops driving the image forming device <NUM> for conveyance at a time T2 greater than the time T1. Further, the second drive controller <NUM> stops driving the fixing device <NUM> for conveyance at a time T3 greater than the time T2.

As described above, driving the image forming device <NUM> for conveyance by the first drive controller <NUM> and driving the fixing device <NUM> for conveyance by the second drive controller <NUM> are performed so as to satisfy conditions of the following formulas <NUM>, <NUM>, and <NUM> with respect to the times T0, T1, T2, and T3. <MAT> <MAT> <MAT>.

Satisfying the above-described formula <NUM> allows the image forming device <NUM> to be driven for conveyance before the fixing device <NUM> is driven for conveyance. Accordingly, a state in which a remaining sheet is jammed at the delivery position B because the conveyance belt <NUM> is not driven for conveyance can be avoided. Satisfying the above-described formula <NUM> allows the remaining sheet to be reliably conveyed to the delivery position B on the exit rotator <NUM> even if the remaining sheet is present in the vicinity of the receiving position A on the entrance rotator <NUM>. Satisfying the above-described formula <NUM> allows the remaining sheet to be reliably conveyed to the sheet detection sensor <NUM> after the remaining sheet is delivered from the exit rotator <NUM> to the conveyance belt <NUM> at the delivery position B. Such a configuration as described above allows the sheet P to be reliably conveyed to the sheet detection sensor <NUM> when the sheet P is present as the remaining sheet in the image forming device <NUM>.

Further, driving for conveyance by the first drive controller <NUM> and the second drive controller <NUM> is performed so as to satisfy the conditions of following formulas <NUM>, <NUM>, and <NUM> in which inequality signs are replaced with equal signs for the formulas <NUM>, <NUM>, and <NUM> described above with respect to the times T0, T1, T2, and T3. Accordingly, the sheet P can be conveyed to the sheet detection sensor <NUM> in a minimum necessary time according to the timing chart illustrated in <FIG>. Thus, the time taken for the initialization process can be reduced. <MAT> <MAT> <MAT>.

In this case, for example, when a remaining sheet is present at the receiving position A on the entrance rotator <NUM>, driving the image forming device <NUM> for conveyance by the first drive controller <NUM> and driving the fixing device <NUM> for conveyance by the second drive controller <NUM> are simultaneously started at the time T0 or T1. Accordingly, the sheet P as the remaining sheet reaches the delivery position B at the time T2. Then, the sheet P reaches a position detected by the sheet detection sensor <NUM> at the time T3.

The timing at which the remaining sheet is detected by the detector <NUM> differs depending on the position of the remaining sheet in the image forming device <NUM>. Accordingly, when driving by the first drive controller <NUM> and the second drive controller <NUM> for conveyance is performed in accordance with the timing chart illustrated in <FIG>, the sheet P as the remaining sheet may be detected by the detector <NUM> before the sheet P reaches the time T3. It is not necessary to continue driving the image forming device <NUM> for conveyance by the first drive controller <NUM> and driving the fixing device <NUM> for conveyance by the second drive controller <NUM> at the time at which the sheet P as the remaining sheet is detected by the detector <NUM>. Accordingly, driving the image forming device <NUM> for conveyance by the first drive controller <NUM> and driving the fixing device <NUM> for conveyance by the second drive controller <NUM> may be stopped at the time at which the remaining sheet is detected by the detector <NUM> as illustrated in <FIG>. Further, as illustrated in <FIG>, the suction operation of the suction device <NUM> by the suction controller <NUM> via the suction drive circuit <NUM> is turned on and off in accordance with the turning on and off of driving the fixing device <NUM> for conveyance by the second drive controller <NUM>. Accordingly, the sheet P is sucked and attracted to the conveyance belt <NUM> by a suction force H that can reliably hold the sheet P while the fixing device <NUM> is driven for conveyance and the sheet P is sucked by a suction force L, which has a weak suction force or no suction force, that can remove the sheet P from the conveyance belt <NUM> when driving the fixing device <NUM> for conveyance is stopped. Thus, when the sheet P is detected, the suction force of the conveyance belt <NUM> is weakened such that the remaining sheet on the conveyance belt <NUM> can be easily removed.

<FIG> is a flowchart illustrating a procedure of remaining sheet ejection processing performed in the image forming apparatus <NUM>, according to the present embodiment. With reference to <FIG>, the procedure of the remaining sheet ejection processing in the initialization process of the image forming apparatus <NUM> according to the present embodiment is described. Note that in <FIG>, driving the image forming device <NUM> for conveyance by the first drive controller <NUM> and driving the fixing device <NUM> for conveyance by the second drive controller <NUM> are performed in accordance with the timing chart illustrated in <FIG>.

At the time T0, the second drive controller <NUM> drives the fixing device <NUM> for conveyance, and at the same time, the suction controller <NUM> causes the suction device <NUM> to perform the suction operation with the suction force H via the suction drive circuit <NUM>. Then, the process proceeds to step S12.

The first drive controller <NUM> drives the image forming device <NUM> for conveyance at the time T1. Accordingly, the sheet P that is present in the image forming device <NUM> as a remaining sheet is conveyed from the image forming device <NUM> toward the fixing device <NUM>. Then, the process proceeds to step S13.

If the detector <NUM> does not detect the sheet P as the remaining sheet based on a detection signal from the sheet detection sensor <NUM> (NO in step S13) even at the time T2, the process proceeds to step S14. On the other hand, when the detector <NUM> detects the sheet P as the remaining sheet based on a detection signal from the sheet detection sensor <NUM> before the sheet P reaches the time T2 (YES in step S13), the process proceeds to step S16.

At the time T2, the first drive controller <NUM> stops driving the image forming device <NUM> for conveyance. Then, the process proceeds to step S15.

Then, at the time T3, the second drive controller <NUM> stops driving the fixing device <NUM> for conveyance.

When the sheet P is detected by the detector <NUM>, the first drive controller <NUM> stops driving the image forming device <NUM> for conveyance and the second drive controller <NUM> stops driving the fixing device <NUM> for conveyance. Then, the suction controller <NUM> switches the suction force generated by the suction device <NUM> from the suction force H to the suction force L via the suction drive circuit <NUM>. Then, the process proceeds to step S17.

Then, the display controller <NUM> causes the display <NUM> to notify, i.e., display that the sheet P as the remaining sheet is detected by the detector <NUM>. As described above, the user can recognize the remaining sheet is present in the image forming device <NUM> and take appropriate measures such as removing the remaining sheet.

The remaining sheet ejection processing in the initialization process of the image forming apparatus <NUM> is executed in the above-described procedure of steps S11, S12, S13, S14, S15, S16, and S17.

As described above, the image forming apparatus <NUM> according to the present embodiment includes the drum <NUM> that rotates and conveys a sheet P while carrying the sheet P on the drum <NUM>, the entrance rotator <NUM> that receives the sheet P conveyed from upstream in the recording medium conveyance direction at the receiving position A and delivers the sheet P to the drum <NUM> while bearing and conveying the sheet P, the exit rotator <NUM> that receives the sheet P conveyed by the rotation of the drum <NUM> and delivers the sheet P at the delivery position B downstream in the recording medium conveyance direction while rotating and conveying the sheet P, the rotation drive circuit <NUM> that rotates the drum <NUM>, the entrance rotator <NUM>, and the exit rotator <NUM>, the conveyance belt <NUM> that receive the sheet P conveyed by the rotation of the exit rotator <NUM> at the second position and convey the sheet P downstream in the recording medium conveyance direction, the conveyance drive circuit <NUM> that drives the conveyance belt <NUM>, and the sheet detection sensor <NUM> that detects the sheet P in the conveyance path in which the sheet P is conveyed by the conveyance belt <NUM>. As a process (initialization process) for removing the sheet P remaining on the drum <NUM>, the entrance rotator <NUM>, and the exit rotator <NUM>, the rotation drive circuit <NUM> starts the rotation operation after driving by the conveyance drive circuit <NUM> for conveyance is started. The rotation drive circuit <NUM> rotates the drum <NUM>, the entrance rotator <NUM>, and the exit rotator <NUM> for a period of time longer than the time taken to convey the sheet P from the receiving position A to the delivery position B. The conveyance drive circuit <NUM> continues driving the conveyance belt <NUM> for conveyance for a period of time equal to or longer than the time taken to convey the sheet P from the delivery position B to a position at which the sheet detection sensor <NUM> detects the sheet P after the rotation operation by the rotation drive circuit <NUM> is stopped. Accordingly, when the sheet P is present as a remaining sheet on the drum surface of the image forming device <NUM>, the remaining sheet can be reliably ejected.

An image forming apparatus 1a as an example of a conveyance apparatus according to a modification of the above-described embodiment is described focusing on points different from the image forming apparatus <NUM> according to the above-described embodiment.

<FIG> is a diagram illustrating an overall configuration of the image forming apparatus 1a according to the modification of the above embodiment of the present disclosure. The overall configuration of the image forming apparatus 1a according to the modification is described with reference to <FIG>.

In the modification, as illustrated in <FIG>, the printer <NUM> of the image forming apparatus 1a includes the image forming device <NUM>, the fixing device <NUM>, a duplex mechanism 50a, a controller 70a, and the display <NUM>.

The duplex mechanism 50a reverses a sheet P that has passed through the fixing device <NUM> and feeds the sheet P again upstream from the image forming device <NUM>, i.e., to the carry-in path <NUM> when printing is performed on both sides of the sheet P. As illustrated in <FIG>, the duplex mechanism 50a includes the reverse path <NUM>, the duplex path <NUM>, a purge tray <NUM>, and a purge tray sensor <NUM>.

The purge tray <NUM> serves as a tray on which a remaining sheet present in the image forming device <NUM> is conveyed via the ejection path <NUM> and the reverse path <NUM> and accumulated by an initialization process performed on the remaining sheet.

The purge tray sensor <NUM> detects, for example, whether the purge tray <NUM> is full of remaining sheets accumulated in the purge tray <NUM>.

Note that the other configuration of the image forming apparatus 1a according to the modification illustrated in <FIG> is similar to the configuration of the image forming apparatus <NUM> according to the above-described embodiments.

<FIG> is a functional block diagram illustrating a configuration of the controller 70a according to the modification of the above-described embodiment. With reference to <FIG>, the configuration and operation of functional blocks of the controller 70a of the image forming apparatus 1a according to the modification is described below.

As illustrated in <FIG>, the controller 70a of the image forming apparatus <NUM> includes the first drive controller <NUM>, the second drive controller <NUM>, the detector <NUM>, the suction controller <NUM>, the display controller <NUM>, a purge conveyance determiner <NUM>, and a purge conveyance controller <NUM>.

The purge conveyance determiner <NUM> determines whether the purge tray <NUM> is full of remaining sheets accumulated in the purge tray <NUM>, in other words, whether the remaining sheets can be conveyed to the purge tray <NUM>, based on a detection signal from the purge tray sensor <NUM> received by the sensor I/F <NUM>. The purge conveyance determiner <NUM> is implemented by executing a program by the CPU <NUM> illustrated in <FIG>.

The purge conveyance controller <NUM> controls the rotation of the conveyance roller pair <NUM> and the conveyance roller pair <NUM> via the conveyance drive circuit <NUM> to convey the sheet P as a remaining sheet conveyed through the ejection path <NUM> to the purge tray <NUM>. The purge conveyance controller <NUM> is implemented by executing a program by the CPU <NUM> illustrated in <FIG>.

Note that the operations of other functional units, e.g., the first drive controller <NUM>, the second drive controller <NUM>, the detector <NUM>, the suction controller <NUM>, and the display controller <NUM> of the controller 70a are the same as the operations of the functional units, e.g., the first drive controller <NUM>, the second drive controller <NUM>, the detector <NUM>, the suction controller <NUM>, and the display controller <NUM> of the controller <NUM> according to the above-described embodiment.

In addition, a part or all of the functions of the first drive controller <NUM>, the second drive controller <NUM>, the detector <NUM>, the suction controller <NUM>, the display controller <NUM>, the purge conveyance determiner <NUM>, and the purge conveyance controller <NUM> may be implemented by an integrated circuit such as an FPGA or an ASIC, instead of a program which is software.

Each functional unit of the controller 70a illustrated in <FIG> conceptually represents a function. However, the controller 70a is not limited to such a configuration. For example, multiple functional units illustrated as independent functional units of the controller 70a illustrated in <FIG> may be as one functional unit. Alternatively, the controller 70a illustrated in <FIG> may divide functions of one functional unit into multiple functional units that serve as the multiple functional units.

<FIG> is a flowchart illustrating a procedure of ejection processing of a remaining sheet performed in the image forming apparatus 1a, according to a modification of the above embodiment of the present disclosure. With reference to <FIG>, the procedure of the ejection processing of the remaining sheet in the initialization process of the image forming apparatus 1a according to the modification is described. Note that in <FIG>, timing at which the image forming device <NUM> and the fixing device <NUM> are driven for conveyance by the first drive controller <NUM> and the second drive controller <NUM>, respectively, is in accordance with the operation of the timing chart illustrated in <FIG>.

The purge conveyance controller <NUM> starts driving the rotation operation of the conveyance roller pair <NUM> and the conveyance roller pair <NUM> via the conveyance drive circuit <NUM>. Then, the process proceeds to step S22.

The second drive controller <NUM> drives the fixing device <NUM> for conveyance at the time T0. Then, the process proceeds to step S23.

The first drive controller <NUM> drives the image forming device <NUM> for conveyance at the time T1. Accordingly, the sheet P that is present in the image forming device <NUM> as a remaining sheet is conveyed from the image forming device <NUM> to the fixing device <NUM>. Then, the process proceeds to step S24.

If the detector <NUM> does not detect the sheet P as the remaining sheet based on a detection signal from the sheet detection sensor <NUM> (NO in step S24) even at the time T2, the process proceeds to step S25. On the other hand, if the detector <NUM> detects the sheet P as the remaining sheet based on a detection signal from the sheet detection sensor <NUM> (YES in step S24), the process proceeds to step S28.

The purge conveyance controller <NUM> stops driving the rotation operation of the conveyance roller pair <NUM> and the conveyance roller pair <NUM> via the conveyance drive circuit <NUM>. Then, the process proceeds to step S26.

Subsequently, at the time T2, the first drive controller <NUM> stops driving the image forming device <NUM> for conveyance. Then, the process proceeds to step S27.

At the time T3, the second drive controller <NUM> stops driving the fixing device <NUM> for conveyance.

Based on a detection signal from the purge tray sensor <NUM>, the purge conveyance determiner <NUM> determines whether the purge tray <NUM> is full of accumulated remaining sheets, in other words, whether remaining sheets can be conveyed to the purge tray <NUM>. When the remaining sheets can be conveyed to the purge tray <NUM> (YES in step S28), the process proceeds to step S29. When the conveyance of the remaining sheets to the purge tray <NUM> is not possible (NO in step S28), the process proceeds to step S30.

When the purge conveyance determiner <NUM> determines that the remaining sheets can be conveyed to the purge tray <NUM>, the purge conveyance controller <NUM> continues driving the rotation operation of the conveyance roller pair <NUM> and the conveyance roller pair <NUM> via the conveyance drive circuit <NUM> for a further predetermined time. Accordingly, the sheets P detected by the detector <NUM> are conveyed through the ejection path <NUM> and the reverse path <NUM> and accumulated in the purge tray <NUM>. Then, the process proceeds to step S30.

The purge conveyance controller <NUM> stops driving the rotation operation of the conveyance roller pair <NUM> and the conveyance roller pair <NUM> via the conveyance drive circuit <NUM>. Further, the first drive controller <NUM> stops driving the image forming device <NUM> for conveyance, and the second drive controller <NUM> stops driving the fixing device <NUM> for conveyance. Then, the process proceeds to step S31.

The display controller <NUM> notifies that the sheet P as the remaining sheet has been detected on the display <NUM>.

In the procedure of steps S21, S22, S23, S24, S25, S26, S27, S29, S30, and S31 described above, the remaining sheet ejection processing in the initialization process of the image forming apparatus 1a is executed. Note that, similar to the operation illustrated in <FIG>, the suction operation by the suction device <NUM> may be combined with driving the fixing device <NUM> for conveyance.

As described above, the image forming apparatus 1a according to the modification additionally includes the purge tray <NUM>, on which sheets P are accumulated, downstream from the conveyance belt <NUM> in the recording medium conveyance direction. When a sheet P is detected by the sheet detection sensor <NUM> and the sheet P can be accumulated in the purge tray <NUM>, the rotation driving circuit <NUM> continues the rotation of the drum <NUM>, the entrance rotator <NUM>, and the exit rotator <NUM> for a predetermined time. The conveyance drive circuit <NUM> continues driving the conveyance belt <NUM> for conveyance for a predetermined time. Accordingly, the sheets P as the remaining sheets can be accumulated on the purge tray <NUM> so that the remaining sheets can be easily collected.

Note that the examples of removing the remaining sheets in the image forming device <NUM> have been described in the above-described embodiments and modification. However, the subject that conveys a print medium with drum-shaped rotators such as the drum <NUM>, the entrance rotator <NUM>, and the exit rotator <NUM> is not limited to the image forming device <NUM>. For example, in some embodiments, the fixing device <NUM> may include a drum-shaped rotator on a conveyance path, and a print medium is heated while the print medium is conveyed by the rotator. In this case, the operations described in the above-described embodiments and modification can be applied to the remaining sheet removal processing in the fixing device <NUM>. Further, the remaining sheet removal processing according to the present embodiment is not only applied to the image forming apparatus <NUM> but to any conveyance apparatus in which a recording medium is conveyed by drum-shaped rotators.

In the above-described embodiments and modification, when at least one of the functional units of the controller <NUM> of the image forming apparatus <NUM> and the controller 70a of the image forming apparatus 1a is implemented by executing a program, the program is provided, for example, in a ROM in advance. Further, the program executed by the controller <NUM> of the image forming apparatus <NUM> according to the above-described embodiments and the controller 70a of the image forming apparatus 1a according to the modification may be recorded and provided in an installable or executable format file on a computer-readable recording medium such as a compact disc read only memory (CD-ROM), a flexible disk (FD), a compact disc-recordable (CD-R), or a digital video disc (DVD). The program executed by the controller <NUM> of the image forming apparatus <NUM> according to the above-described embodiments and the controller 70a of the image forming apparatus 1a according to the modification may be stored on a computer connected to a network such as the Internet and downloaded and provided via the network. The program executed by the controller <NUM> of the image forming apparatus <NUM> according to the above-described embodiments and the controller 70a of the image forming apparatus 1a according to the modification may be provided or distributed via a network such as the Internet. In addition, the program executed by the controller <NUM> of the image forming apparatus <NUM> according to the above-described embodiments and the controller 70a of the image forming apparatus 1a according to the modification have a module configuration including at least one of the above-described functional units. A CPU as hardware reads the program from the above-described storage device and executes the program. Accordingly, the above-described functional units are loaded onto a main storage device and generated.

Further, each function in the above-described embodiments can be realized by one or more processing circuits. In the present embodiment, the term processing circuit includes a processor programmed by software to execute each function, such as a processor implemented by an electronic circuit, and a device such as an application specific integrated circuit (ASIC), a digital signal processor (DSP), a field-programmable gate array (FPGA) or a circuit module known in the art designed to execute each of the above-described functions.

Claim 1:
A conveyance apparatus (<NUM>, 1a) comprising:
a bearing rotator (<NUM>) configured to rotate, while bearing a recording medium, to convey the recording medium;
an entrance rotator (<NUM>) configured to receive, at a first position (A), the recording medium fed from upstream in a recording medium conveyance direction and deliver the recording medium to the bearing rotator (<NUM>) while rotating to convey the recording medium;
an exit rotator (<NUM>) configured to receive the recording medium conveyed by rotation of the bearing rotator (<NUM>) and deliver the recording medium at a second position (B) downstream in the recording medium conveyance direction while rotating to convey the recording medium;
a first driver (<NUM>) configured to rotate the bearing rotator (<NUM>), the entrance rotator (<NUM>), and the exit rotator (<NUM>);
a downstream conveyor (<NUM>) configured to receive, at the second position (B), the recording medium conveyed by rotation of the exit rotator (<NUM>) and convey the recording medium downstream in the recording medium conveyance direction;
a second driver (<NUM>) configured to drive the downstream conveyor (<NUM>) for conveyance; and
a recording medium detector (<NUM>) configured to detect the recording medium on a conveyance path on which the recording medium is conveyed by the downstream conveyor (<NUM>),
characterized in that the first driver (<NUM>) is configured to: as a process of removing the recording medium remaining on at least one of the bearing rotator (<NUM>), the entrance rotator (<NUM>), or the exit rotator (<NUM>),
start rotation operation after the second driver (<NUM>) starts driving the downstream conveyor (<NUM>) for conveyance; and
rotate the bearing rotator (<NUM>), the entrance rotator (<NUM>), and the exit rotator (<NUM>) for a period of time equal to or longer than a period of time taken for the recording medium to be conveyed from the first position (A) to the second position (B), and
wherein the second driver (<NUM>) is configured to continue driving the downstream conveyor (<NUM>) for conveyance for a period of time equal to or longer than a period of time taken for the recording medium to be conveyed from the second position (B) to a position at which the recording medium is detected by the recording medium detector (<NUM>) after the rotation operation of the first driver (<NUM>) is stopped.