Patent Description:
Various types of image forming apparatuses such as printers or copiers include a fixing device that includes a fixing roller pair to fix a toner image formed on a sheet by application of heat and pressure. Image forming apparatuses in the related art are known that are provided with a sheet lamination mode capable of performing an operation in which a lamination sheet that is a sheet sandwiched by two lamination films is conveyed to the fixing device where one sides of the lamination films are melted and bonded together (i.e., sheet laminating operation). <CIT> discloses background art to the invention.

In an image forming apparatus in the related art having a typical sheet lamination mode, the fixing device of the image forming apparatus applies thermal energy to the lamination films to be melted and bonded together when the sheet laminating operation is performed. However, when any abnormal condition such as misfeeding occurs, the operation of the image forming apparatus is stopped from a safety point of view and the power to the heater provided for the fixing device is turned off. For this reason, when the image forming apparatus stops at high temperature during the sheet laminating operation, the rotation of the fixing roller pair also stops at high temperature. As a result, heat is concentrated on the nip region of the fixing roller pair, which causes damage on the rollers such as deformation of the fixing roller pair in the nip region, as illustrated in <FIG>.

For this reason, as the abnormal condition handling, the fixing roller pair is rotated for a certain period of time to radiate heat after the power to the heater of the fixing device is immediately turned off (hereinafter, also referred to as "immediate turnoff of the heater"). By so doing, the deformation of the fixing roller pair in the nip region can be prevented, as illustrated in <FIG>. However, although the degree of damage on the rollers of the fixing roller pair varies depending on the temperature of the fixing roller pair and the heater lighting percentage before the abnormal condition handling, rotating the fixing roller pair for a certain period of time makes the period of the stopping process unnecessarily long regardless of these conditions, and also makes the waiting time before restarting the job long.

<CIT> discloses an image forming apparatus including a fixing device that determines that the state of the fixing device is an abnormal condition when the detected temperature of the heat roller is higher than the upper limit temperature of the permissible temperature range, stops the heating of the heat roller by the halogen lamp, and rotate the heat roller. This operation is performed to prevent the heat roller of the fixing device from being damaged even when the temperature of the heat roller reaches an abnormally high temperature in the fixing device of the image forming apparatus in the related art.

The above-described operation employs a technique related to a stop control of the heat roller at the time of occurrence of an abnormal condition. However, rotating the heat roller for a certain period of time takes a long time to end the stopping process, and also takes a long time to restart the job.

In view of the above-described disadvantages, an object of the present disclosure is to provide a sheet laminator and an image forming system to reduce the stopping process time and prevent damage on a fuser pressure member such as deformation of the fuser pressure member in the nip region.

Embodiments of the present disclosure described herein provide a novel sheet laminator includes a fuser pressure member, a heater, a driver, and a controller. The fuser pressure member thermally fixes a two-ply sheet and a sheet medium inserted between two sheets of the two-ply sheet. The heater heats the fuser pressure member. The driver rotates the fuser pressure member. In response to a pause of a rotation of the fuser pressure member, the controller turns off a power supply to the heater, and perform one of immediately stopping the fuser pressure member or rotating the fuser pressure member and stopping the fuser pressure member after the rotation of the fuser pressure member, based on a state of the fuser pressure member.

Further, embodiments of the present disclosure described herein an image forming system including provide the above-described sheet laminator, and an image forming apparatus to form an image on the sheet medium to be supplied to the sheet laminator.

According to the present disclosure, a sheet laminator and an image forming system reduce the stopping process time and prevent damage on a fuser pressure member such as deformation of the fuser pressure member in the nip region.

Exemplary embodiments of this disclosure will be described in detail based on the following figures, wherein:.

It will be understood that if an element or layer is referred to as being "on," "against," "connected to" or "coupled to" another element or layer, then it can be directly on, against, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, if an element is referred to as being "directly on," "directly connected to" or "directly coupled to" another element or layer, then there are no intervening elements or layers present. As used herein, the term "connected/coupled" includes both direct connections and connections in which there are one or more intermediate connecting elements.

Spatially relative terms, such as "beneath," "below," "lower," "above," "upper" and the like may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. For example, if the device in the figures is turned over, elements describes as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, term such as "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated <NUM> degrees or at other orientations) and the spatially relative descriptors herein interpreted accordingly.

The terminology used herein is for describing particular embodiments and examples and is not intended to be limiting of exemplary embodiments of this disclosure. It will be further understood that the terms "includes" and/or "including," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

A description is given of a sheet processing device according to an embodiment of the present disclosure, with reference to <FIG>.

<FIG> is a schematic diagram illustrating an overall configuration of a sheet laminator according to an embodiment of the present disclosure.

A sheet laminator <NUM> according to the present embodiment is to separate two sheets (plies) of a two-ply sheet (hereinafter referred to as a lamination sheet S) and to insert and sandwich a sheet-shaped medium (hereinafter referred to as an inner sheet P) between the separated sheets of the two-ply sheet.

The lamination sheet S is a two-ply sheet in which two sheets are overlapped and bonded together at a portion (or a side) of the two-ply sheet. For example, a two-ply sheet has two sheets (two sides). A first side of the two-ply sheet serves as a transparent sheet such as a transparent polyester sheet, a second side of the two-ply sheet serves as a transparent or opaque sheet is disposed facing the first side, and the first and second sides are bonded at one side of the two-ply sheet. The two-ply sheet also includes a lamination film.

The inner sheet P is an example of the sheet medium that is inserted into the two-ply sheet. The sheet medium may be, for example, thick paper, postcards, envelopes, plain paper, thin paper, coated paper, art paper, tracing paper, and overhead projector (OHP) transparencies.

As illustrated in <FIG>, the sheet laminator <NUM> includes a sheet tray <NUM> serving as a first stacker that stacks lamination sheets S, a pickup roller <NUM> that feeds the lamination sheets S from the sheet tray <NUM>, and first conveyance roller pair <NUM>. The sheet tray <NUM> of the sheet laminator <NUM> is provided with a plurality of size detection sensors C11 for detecting the size of the lamination sheet S.

A lamination sheet S into which an inner sheet has been inserted is ejected and stacked on the sheet ejection tray <NUM> by a third conveyance roller pair <NUM> or a roller disposed downstream from the third conveyance roller pair <NUM>. The sheet ejection tray <NUM> is disposed inside a housing of the sheet laminator <NUM>. Such a configuration facilitates a vertical conveyance of the lamination sheet S toward the sheet ejection tray <NUM>.

A conveyance sensor C1 is disposed downstream from the first conveyance roller pair <NUM> in the sheet conveyance direction to detect the sheet conveyance position of the lamination sheet S.

A conveyance sensor C2 is disposed downstream from an entrance roller pair <NUM> and upstream from an exit roller pair <NUM> in the sheet conveyance direction to detect the sheet conveyance position of the inner sheet P.

The sheet laminator <NUM> further includes, for example, a second conveyance roller pair <NUM>, a winding roller <NUM> serving as a rotary member, a third conveyance roller pair <NUM>, a fourth conveyance roller pair <NUM>, a fifth conveyance roller pair <NUM>, an ejection roller pair <NUM>, and the sheet ejection tray <NUM>, disposed downstream from the first conveyance roller pair <NUM> in the sheet conveyance direction. The sheet laminator <NUM> further includes separation members <NUM> disposed between the winding roller <NUM> and the third conveyance roller pair <NUM>. The separation members <NUM> are movable in the width direction of the lamination sheet S. The separation members <NUM> serve as a separator that separates the lamination sheet S according to the present embodiment.

A sheet conveyance sensor C3 is disposed downstream from the second conveyance roller pair <NUM> in the sheet conveyance direction to detect the conveyance position of the lamination sheet S and the sheet conveyance position of the inner sheet P.

An abnormal condition detection sensor C4 is disposed downstream from the winding roller <NUM> in the sheet conveyance direction to detect the condition of the lamination sheet S.

A conveyance sensor C5 that detects the conveyance position of the lamination sheet S is disposed downstream from the third conveyance roller pair <NUM> in the sheet conveyance direction.

The pickup roller <NUM>, the first conveyance roller pair <NUM>, the second conveyance roller pair <NUM>, and the winding roller <NUM> are some examples of a first feeder.

In <FIG>, each set of the second conveyance roller pair <NUM> and the third conveyance roller pair <NUM> is, for example, a pair of two rollers and is rotationally driven by a drive device (e.g., a motor). The second conveyance roller pair <NUM> rotates in one direction. The third conveyance roller pair <NUM> rotates in forward and reverse directions, thereby nipping and conveying the lamination sheet S and the inner sheet P.

The second conveyance roller pair <NUM> conveys the lamination sheet S and the inner sheet P vertically downward toward the third conveyance roller pair <NUM>.

On the other hand, the third conveyance roller pair <NUM> can switch the direction of rotation between the forward direction and the reverse direction that is a direction opposite to the forward direction. The third conveyance roller pair <NUM> can nip and convey the lamination sheet S vertically downward toward the sheet ejection tray <NUM> and also convey the lamination sheet S vertically upward toward the winding roller <NUM> in the reverse direction, that is, a direction to pull back the lamination sheet S.

The sheet laminator <NUM> further includes a sheet separation device <NUM> between the second conveyance roller pair <NUM> and the third conveyance roller pair <NUM>. The sheet separation device <NUM> includes the winding roller <NUM> serving as a rotary member and the separation members <NUM>. The winding roller <NUM> is driven by a winding roller motor 109a (see <FIG>) that serves as a drive unit to rotate in the forward and reverse directions. The direction of rotation of the winding roller <NUM> is switchable between the forward direction (clockwise direction) and the reverse direction (counterclockwise direction).

The winding roller <NUM> includes a roller <NUM> and a sheet gripper <NUM> movably disposed on the roller <NUM> to grip the sheet S. The sheet gripper <NUM> is driven by a sheet gripper motor 110a (see <FIG>) to be rotatable with the roller <NUM>. The sheet gripper <NUM> grips the leading end of the lamination sheet S with the roller <NUM>. In the present embodiment, the sheet gripper <NUM> and the roller <NUM> are separate units. However, the sheet gripper <NUM> may be formed on the outer circumference of the roller <NUM> as a single unit serving as a handle.

A description is now given of a series of operations performed in the sheet laminator <NUM>, with reference to <FIG>. The series of operations performed by the sheet laminator <NUM> indicates the operations from separating the lamination sheet S to inserting the inner sheet P into the lamination sheet S.

In <FIG>, multiple lamination sheets S are stacked on the sheet tray <NUM> such that a bonded end of each of the multiple lamination sheets S is located downstream from the pickup roller <NUM> in the sheet feed direction (sheet conveyance direction). The sheet laminator <NUM> picks the lamination sheet S on the sheet tray <NUM> by the pickup roller <NUM> and conveys the lamination sheet S toward the first conveyance roller pair <NUM>.

The lamination sheet S is then conveyed toward the winding roller <NUM> by the second conveyance roller pair <NUM> disposed downstream from the first conveyance roller pair <NUM> in the sheet conveyance direction. In the sheet laminator <NUM>, the second conveyance roller pair <NUM> conveys the lamination sheet S with the bonded end, which is one of four sides of the lamination sheet S, as a downstream end in the vertical direction (i.e., a vertically downward direction).

Subsequently, when the trailing end of the lamination sheet S in the vertical direction (i.e., the vertically downward direction) passes by the winding roller <NUM>, the sheet laminator <NUM> temporarily stops the conveyance.

The sheet laminator <NUM> then opens the sheet gripper <NUM>, reverses the rotation direction of the third conveyance roller pair <NUM>, and conveys the lamination sheet S vertically upward toward the opening of the sheet gripper <NUM>.

Subsequently, the sheet laminator <NUM> stops rotation of the third conveyance roller pair <NUM> to stop conveyance of the lamination sheet S when the trailing end of the lamination sheet S is inserted into the opened portion of the sheet gripper <NUM>, and closes the sheet gripper <NUM> to grip the trailing end of the lamination sheet S. These operations are performed when the lamination sheet S is conveyed by the designated amount.

The sheet laminator <NUM> then rotates the winding roller <NUM> in the clockwise direction to wind the lamination sheet S around the winding roller <NUM>. The lamination sheet S is wound around the winding roller <NUM> from the side where the two sheets of the lamination sheet S are overlapped but not bonded.

When the lamination sheet S that is the two-ply sheet is wound around the winding roller <NUM>, a winding circumferential length difference (in other words, a winding circumferential amount difference) is created between the two sheets in the amount of winding of the lamination sheet S around the circumference of the winding roller <NUM>. There is a surplus of the sheet on the inner circumferential side to the center of the winding roller <NUM>, which generates a slack toward the bonded end. As a result, a space is created between the two sheets of the lamination sheet S. As the separation members <NUM> are inserted into the space formed as described above, from opposed sides of the lamination sheet S, the space between the two sheets is reliably maintained. In response to detection of the leading end of the lamination sheet S with the sheet conveyance sensor C5, the lamination sheet S is conveyed from the sheet conveyance sensor C5 by a designated amount to perform these operations.

The sheet laminator <NUM> rotates the winding roller <NUM> counterclockwise in a state where the separation members <NUM> are inserted into the space generated in the lamination sheet S, and moves the space where the lamination sheet S is separated to the trailing end of the lamination sheet S in the vertical direction (i.e., the vertically downward direction). After the winding roller <NUM> has been rotated by a designated amount, the sheet laminator <NUM> causes the sheet gripper <NUM> to open. As a result, the lamination sheet S is separated into the upper and lower sheets at the trailing end.

In this state, the sheet laminator <NUM> causes the driver to temporarily stop the conveyance of the lamination sheet S and to further move the separation members <NUM> in the width direction of the lamination sheet S from both ends toward the center to separate the whole area of the trailing end of the lamination sheet S. In response to detection of the leading end of the lamination sheet S with the sheet conveyance sensor C5, the lamination sheet S is conveyed from the sheet conveyance sensor C5 by a designated amount to perform these operations.

The sheet laminator <NUM> then rotates the third conveyance roller pair <NUM> counterclockwise to convey the lamination sheet S in the reverse conveyance direction. A branching member <NUM> can be switched at the time when the leading end of the lamination sheet S passes through the conveyance sensor C5. When the lamination sheet S is conveyed to the non-thermal pressure conveyance passage, the branching member <NUM> remains at the position illustrated in <FIG>. When the lamination sheet S is to be conveyed to a thermal pressure conveyance passage <NUM>, the branching member <NUM> is switched to the side where the lamination sheet S is guided to the thermal pressure conveyance passage <NUM>.

The separation members <NUM> guide the two sheets separated from the lamination sheet S in the right and left directions in <FIG>, and thus the two sheets are fully separated. Then, the sheet laminator <NUM> temporarily stops the conveyance of the lamination sheet S and brings the joined portion of the lamination sheet S into a state of being gripped (nipped) by the third conveyance roller pair <NUM>. Accordingly, one end of the lamination sheet S is bonded as the bonded side of the lamination sheet S and the other end of the lamination sheet S is opened largely.

In response to the detection of the leading end of the lamination sheet S with the sheet conveyance sensor C5, the lamination sheet S is conveyed from the sheet conveyance sensor C5 by a designated amount to perform these operations.

The sheet laminator <NUM> then rotates the second conveyance roller pair <NUM> to convey the inner sheet P conveyed from the image forming apparatus side vertically downward toward the third conveyance roller pair <NUM>. The image forming apparatus will be described below with reference to <FIG>.

Subsequently, the sheet laminator <NUM> rotates the third conveyance roller pair <NUM> to merge the lamination sheet S and the inner sheet P, and inserts the inner sheet P into the opened lamination sheet S.

The operation from separation (peeling) of the lamination sheet S to insertion of the inner sheet P has been described above. As illustrated with reference letters SR in <FIG>, the two sheets of the lamination sheet S are separated and conveyed separately in left and right directions respectively.

The sheet laminator <NUM> then causes the third conveyance roller pair <NUM> to convey the lamination sheet S, in which the inner sheet P has been inserted, downward in the vertical direction. Thus, the two sheets of the lamination sheet S overlap again and the opening of the lamination sheets S is closed. The lamination sheet S in which the inner sheet P has been sandwiched is conveyed to a fixing device having a thermal pressure roller pair <NUM> (corresponding to a fuser pressure member) as a pair of rollers by the third conveyance roller pair <NUM> or, for example, a roller disposed downstream from the third conveyance roller pair <NUM> in the sheet conveyance direction of the lamination sheet S.

When passing through the thermal pressure roller pair <NUM>, the lamination sheet S is thermally pressed and fixed. After passing through the thermal pressure roller pair <NUM>, the lamination sheet S continues to be conveyed vertically downward toward the sheet ejection tray <NUM> and is stacked on the sheet ejection tray <NUM>. Since the lamination sheet S pressed after passing through the thermal pressure roller pair <NUM> is ejected vertically downward in this manner, the lamination sheet S can be stacked on the sheet ejection tray <NUM> while preventing the heated lamination sheet S from being bent by an external force.

More specifically, in the vertical conveyance according to the present embodiment, the lamination sheet S is ejected vertically downward. Accordingly, the gravity applied to the lamination sheet S is parallel to the tangent line of a fixing nip between the rollers of the thermal pressure roller pair <NUM>, and an external force that may deform the lamination sheet S is not applied to the lamination sheet S. Thus, as long as the lamination sheet S continues to be ejected vertically, deformation of the lamination sheet S is reduced. The sheet ejection tray <NUM> is disposed after the trailing end of the lamination sheet S passes through the thermal pressure roller pair <NUM> and the ejection roller pair <NUM>, and the lamination sheet S is cooled before reaching the sheet ejection tray <NUM>. Accordingly, the inclination of the stacking surface of the sheet ejection tray <NUM> does not apply an external force that may deform the lamination sheet S to the lamination sheet S.

As the lamination sheet S is conveyed vertically downward, the lamination sheet S continues to be conveyed vertically downward until the leading end of the lamination sheet S reaches the thermal pressure roller pair <NUM> and the trailing end of the lamination sheet S completely passes through the thermal pressure roller pair <NUM>. Accordingly, the vertical conveyance of the lamination sheet S is given, thus preventing the bending of the thermally-pressed lamination sheet S due to the external force.

The sheet laminator <NUM> performs a series of operations, in this order, of feeding the lamination sheet S, separating the lamination sheet S, inserting the inner sheet P into the lamination sheet S, and laminating the lamination sheet S with the inner sheet P being inserted, by application of heat and pressure, on a stand-alone basis. This series of operations is carried out automatically without any aid of a user, and therefore the sheet laminator <NUM> can enhance and provide the convenience better than a known sheet laminator employing a known technique. Since the sheet laminator <NUM> includes the fixing device including the thermal pressure roller pair <NUM> and can perform a sheet laminating operation, the sheet laminator <NUM> may be referred to as a lamination processing apparatus in a narrow sense.

<FIG> is an enlarged view of a part of from the thermal pressure roller pair <NUM> to the sheet ejection tray <NUM>, according to an embodiment of the present disclosure.

In this example, multiple lamination sheets (laminated sheets SG) are stacked on the sheet ejection tray <NUM>. As illustrated in <FIG>, a distance L from the fixing nip region of the thermal pressure roller pair <NUM> to the stacking surface of the sheet ejection tray <NUM> or the uppermost surface of the laminated sheets SG stacked on the sheet ejection tray <NUM> on an extension line of a sheet conveyance passage is longer than the length of the lamination sheet S in the sheet conveyance direction. Accordingly, the leading end of the lamination sheet S does not contact the stacking surface of the sheet ejection tray <NUM> or the stacked laminated sheets SG until the trailing end of the lamination sheet S completely passes through the thermal pressure roller pair <NUM>, thus preventing the heated lamination sheet S from being bent by an external force.

The sheet ejection tray <NUM> can stack lamination sheets S up to a thickness of, for example, <NUM>. In order to detect the full state of the laminated sheets SG, a tray full detection sensor <NUM> (e.g., a laser displacement meter) that serves as an optical sensor to detect the uppermost surface of the stacked laminated sheets SG is provided with the sheet ejection tray <NUM>. In this case, the distance L is longer than the length of the lamination sheet S in the sheet conveyance direction at least up to the thickness of <NUM> of laminated sheets SG.

<FIG> is an enlarged view of a part of from the thermal pressure roller pair <NUM> to the sheet ejection tray <NUM>, according to another embodiment of the present disclosure.

In this example, more sheets (laminated sheets SG) than in the example illustrated in <FIG> are stacked on the sheet ejection tray <NUM>. As illustrated in <FIG>, when the leading end of the lamination sheet S during sheet ejection from the ejection roller pair <NUM> contacts the uppermost surface of the laminated sheets SG after fixing in the sheet ejection tray <NUM>, the lamination sheet S is bent.

The sheet laminator <NUM> has a configuration in which a distance D between a contact point of the leading end of the lamination sheet S during sheet ejection and the uppermost surface of the laminated sheets SG and a vertical line passing through the nip region of the ejection roller pair <NUM> is equal to or less than <NUM>. For example, the tray full detection sensor <NUM> (for example, a laser-displacement meter) is disposed at the sheet ejection tray <NUM> to detect the distance to the uppermost sheet of the stacked laminated sheets SG that is at a position where the distance D is <NUM>. Such a configuration can determine whether the distance D is equal to or less than <NUM>.

Setting the distance D to be equal to or less than <NUM> can reduce the bending of the lamination sheet S and enhance the stacking performance, even if the leading end of the lamination sheet S contacts the uppermost surface of the laminated sheets SG during sheet ejection of the lamination sheet S. When the tray full detection sensor <NUM> detects that the distance D exceeds <NUM>, the sheet laminator <NUM> determines that the sheet ejection tray <NUM> is full, and stops fixing and conveying the lamination sheet S. Preventing the distance D from exceeding <NUM> in this manner can prevent the lamination sheet S from being largely bent when the leading end of the lamination sheet S contacts the uppermost surface of the laminated sheets SG during sheet ejection of the lamination sheet S. Note that the numerical value "<NUM>" is merely an example, and is a numerical value determined by evaluating in advance the thickness of the lamination sheet S and the inner sheet P to be used depending on the specifications of the sheet laminator.

As illustrated in <FIG>, the ejection roller pair <NUM> that ejects the lamination sheet S toward the sheet ejection tray <NUM> are disposed downstream from the thermal pressure roller pair <NUM> in the sheet conveyance direction. Ejecting the lamination sheet S by the ejection roller pair <NUM> can reduce the formation of wrinkles on the lamination sheet S after thermal pressing. Ejecting the lamination sheet S in the vertical direction by the ejection roller pair <NUM> can reduce bending of the lamination sheet S after the thermal pressing.

<FIG> is a block diagram illustrating a hardware configuration for executing control processing executed in the sheet laminator <NUM>.

As illustrated in <FIG>, the sheet laminator <NUM> includes a central processing unit (CPU) <NUM>, a random access memory (RAM) <NUM>, a read only memory (ROM) <NUM>, a hard disk drive (HDD) <NUM>, and an interface (I/F) <NUM>. The CPU <NUM>, the RAM <NUM>, the ROM <NUM>, the HDD <NUM>, and the I/F <NUM> are connected to each other.

The CPU <NUM> is an arithmetic unit and controls the overall operation of the sheet laminator <NUM>.

The RAM <NUM> is a volatile storage medium that allows data to be read and written at high speed. The CPU <NUM> uses the RAM <NUM> as a work area for data processing.

The ROM <NUM> is a read-only non-volatile storage medium that stores programs such as firmware. The HDD <NUM> is a non-volatile storage medium that allows data to be read and written and has a relatively large storage capacity.

The HDD <NUM> stores, e.g., an operating system (OS), various control programs, and application programs.

The sheet laminator <NUM> processes, by an arithmetic function of the CPU <NUM>, e.g., a control program stored in the ROM <NUM> and an information processing program (or application program) loaded into the RAM <NUM>. Such processing configures a software controller including various functional modules of the sheet laminator <NUM>. The software controller thus configured cooperates with hardware resources of the sheet laminator <NUM> to construct functional blocks to implement functions of the sheet laminator <NUM>. In other words, the CPU <NUM>, the RAM <NUM>, the ROM <NUM>, and the HDD <NUM> implement a controller <NUM> (control unit) to control the operation of the sheet laminator <NUM>.

The I/F <NUM> is an interface that connects the pickup roller <NUM>, the first conveyance roller pair <NUM>, the second conveyance roller pair <NUM>, the third conveyance roller pair <NUM>, the fourth conveyance roller pair <NUM>, the fifth conveyance roller pair <NUM>, the ejection roller pair <NUM>, the size detection sensors C11, the conveyance sensors C1, C2, C3, C4, C5, and C12, the winding roller motor 109a, the sheet gripper motor 110a, a separation member motor 116a, a branching member motor 118a, a thermal pressure roller motor 129a, a heater <NUM> (corresponding to the heating device), thermistors <NUM> (corresponding to the temperature detector), the tray full detection sensor <NUM>, and the operation panel <NUM> to the controller <NUM>.

The controller <NUM> controls the operations of the pickup roller <NUM>, the first conveyance roller pair <NUM>, the second conveyance roller pair <NUM>, the third conveyance roller pair <NUM>, the fourth conveyance roller pair <NUM>, the fifth conveyance roller pair <NUM>, the ejection roller pair <NUM>, the winding roller motor 109a, the sheet gripper motor 110a, the separation member motor 116a, the branching member motor 118a, the thermal pressure roller motor 129a, and the heater <NUM>, via the I/F <NUM>. In addition, the controller <NUM> acquires detection results from the size detection sensor C11, the conveyance sensors C1, C2, C3, C4, C5, and C12, the thermistors <NUM>, and the tray full detection sensor <NUM>.

The winding roller motor 109a is a drive unit to drive the winding roller <NUM> in the forward and reverse directions. The sheet gripper motor 110a is a drive unit to rotate the sheet gripper <NUM>. The separation member motor 116a is a drive unit to move the separation members <NUM> in the width direction of the lamination sheet S. The branching member motor 118a is a drive unit to switch the position of the branching member <NUM>.

<FIG> is a flowchart of a sheet ejecting operation of the sheet laminator <NUM>, according to an embodiment of the present disclosure.

After the start of a thermal pressing operation in the fixing device that includes the thermal pressure roller pair <NUM>, the sheet laminator <NUM> determines whether the trailing end of the lamination sheet S has passed through the thermal pressure roller pair <NUM>, in step S1. For this determination, the sheet laminator <NUM> includes a detector (sensor) that detects the lamination sheet S, and the detector is, for example, the conveyance sensor C12 (see <FIG>) disposed downstream from the thermal pressure roller pair <NUM> in the sheet conveyance direction of the lamination sheet S.

When the trailing end of the lamination sheet S completely passes through the thermal pressure roller pair <NUM> (YES in step S1), the sheet laminator <NUM> stops the sheet ejecting operation of the lamination sheet S in step S2, and holds the lamination sheet S by the ejection roller pair <NUM>. Then in step S3, a timer in the sheet laminator <NUM> sets a waiting time T based on the size of the lamination sheet S detected by the size detection sensors C <NUM>, and the controller <NUM> determines whether the waiting time T has elapsed, in step S4. When the waiting time T has not elapsed (NO in step S4), step S4 is repeated until the waiting time T elapses. When the waiting time T has elapsed (YES in step S4), the sheet laminator <NUM> resumes the sheet ejecting operation of the lamination sheet S in step S5, and ejects the lamination sheet S.

As described above, the sheet laminator <NUM> stops the ejection roller pair <NUM>, holds the lamination sheet S by the ejection roller pair <NUM>, and resumes the sheet ejecting operation after waiting for the waiting time T (required time) to elapse. Accordingly, the lamination sheet S is ejected after waiting for a decrease of the temperature of the thermally-pressed lamination sheet S, thus reducing the bending of the lamination sheet S.

<FIG> is a flowchart of a sheet ejecting operation of the sheet laminator <NUM>, according to another embodiment of the present disclosure.

After the start of a thermal pressing operation in the fixing device that includes the thermal pressure roller pair <NUM>, the sheet laminator <NUM> determines whether the trailing end of the lamination sheet S has passed through the thermal pressure roller pair <NUM>, in step S11. For this determination, the sheet laminator <NUM> includes a detector (sensor) that detects the lamination sheet S, and the detector is, for example, the conveyance sensor C12 (see <FIG>) disposed downstream from the thermal pressure roller pair <NUM> in the sheet conveyance direction of the lamination sheet S.

When the trailing end of the lamination sheet S has not completely passed through the thermal pressure roller pair <NUM> (NO in step S11), step S11 is repeated until the trailing end of the lamination sheet S completely passes through the thermal pressure roller pair <NUM>. When the trailing end of the lamination sheet S has completely passed through the thermal pressure roller pair <NUM> (YES in step S11), the sheet laminator <NUM> increases the rotation speed of the ejection roller pair <NUM> in step S12 to increase the conveyance speed of the lamination sheet S. Accordingly, the time during which the leading end of the thermally-pressed lamination sheet S contacts the stacking surface of the sheet ejection tray <NUM> or the uppermost surface of the stacked sheets SG is shortened, and thus the bending of the lamination sheet S can be reduced.

<FIG> is a diagram illustrating an overall configuration of an image forming system including the sheet laminator according to an embodiment of the present disclosure and an image forming apparatus.

An image forming system <NUM> includes an image forming apparatus <NUM> that forms an image on, for example, an inner sheet P, and the sheet laminator <NUM> as an external sheet processing apparatus. The sheet laminator <NUM> includes a sheet tray <NUM> on which lamination sheets S are stacked, and receives inner sheets P fed from the image forming apparatus <NUM> to the sheet laminator <NUM> via a relay device <NUM>. Accordingly, the image forming apparatus <NUM> (e.g., a printer or a copier) can insert an inner sheet P on which an image is formed into the lamination sheet S in an in-line system. Thus, the image forming system <NUM> can perform a series of operations of, in this order, the feeding of the lamination sheet S, the separation of the lamination sheet S, the insertion of the inner sheet P into the lamination sheet S, and the sheet laminating operation by application of heat and pressure without using manpower.

An operation panel <NUM> is disposed in an exterior portion of the image forming apparatus <NUM>. The operation panel <NUM> serves as a display operation device to display information in the image forming apparatus <NUM> and receives an operation input by a user. In addition, the operation panel <NUM> also serves as a notification device that issues a perceptual signal to the user. Alternatively, a notification device other than the operation panel <NUM> may be separately disposed in the image forming apparatus <NUM>.

<FIG> is a diagram illustrating another overall configuration of an image forming system including a sheet laminator according to another embodiment of the present disclosure, and an image forming apparatus.

The image forming system <NUM> includes the image forming apparatus <NUM>, the relay device <NUM>, the sheet laminator <NUM>, and a post-processing apparatus <NUM>.

The image forming system <NUM> according to the present embodiment feeds an inner sheet P on which an image is formed by the image forming apparatus <NUM> from the sheet laminator <NUM> via the relay device <NUM>. The post-processing apparatus <NUM> serving as a post-processing apparatus other than the sheet laminator <NUM> is disposed downstream from the sheet laminator <NUM> in the sheet conveyance direction. As described above, the post-processing apparatus <NUM> that serves as a post-processing apparatus other than the sheet laminator <NUM> is disposed downstream from the sheet laminator <NUM> in the sheet conveyance direction. By so doing, when a print job that does not require the sheet laminating operation and requires another post-processing operation (e.g., the binding operation or the sheet folding operation) is executed, the image forming system <NUM> causes a sheet (i.e., the inner sheet P) conveyed from the image forming apparatus <NUM> to be simply passed through the sheet laminator <NUM> to convey to the post-processing apparatus <NUM>. Accordingly, the post-processing apparatus <NUM> can perform the post-processing operation on the sheet (i.e., the inner sheet P). As a result, the image forming system <NUM> can be used according to the needs of the user without reducing the efficiency. As the image forming system <NUM> illustrated in <FIG>, the post-processing apparatus <NUM> is provided to perform the post-processing operations including the punching operation and the stapling operation, on the lamination sheet S ejected from the image forming apparatus <NUM> through the sheet laminator <NUM> (in other words, on the lamination sheet S without the sheet laminating operation). In such a case, the lamination sheet S is ejected to an ejection tray <NUM> of the post-processing apparatus <NUM> after the post-processing operation has been performed on the lamination sheet S.

Next, a detailed description is given of the fixing device according to an embodiment of the present disclosure.

<FIG> is a schematic view of the fixing device including the thermal pressure roller pair <NUM>.

The thermal pressure roller pair <NUM> is a roller including a fluororesin layer (perfluoroalkoxy tube or PFA tube) 120A as a surface layer, a rubber layer 120B as an elastic layer disposed close to the heater <NUM> from the surface layer, and a core metal portion 120C at the center portion close to the heater <NUM> from the elastic layer. By using a fluororesin layer as the surface layer, dirt is less likely to adhere to the surface layer. However, since the fluororesin layer is easily damaged by heat, the continuous rotation operation of the thermal pressure roller pair <NUM> before stopping is required in some cases. The thermal pressure roller pair <NUM> is formed as a pair of rollers between which a nip region for nipping the lamination sheet S is formed. The heater <NUM> serving as a heating unit is provided inside each of the rollers of the thermal pressure roller pair <NUM> to heat the thermal pressure roller pair <NUM>. The thermistors <NUM> each serving as a temperature detector are disposed facing the thermal pressure roller pair <NUM> at the entrance of the nip region to detect the temperature of the thermal pressure roller pair <NUM> that is heated. The thermistors <NUM> and the heaters <NUM> are connected to the controller <NUM>. Further, a drive unit <NUM> (corresponding to the drive unit) that rotates the thermal pressure roller pair <NUM> is connected to the thermal pressure roller pair <NUM>. The thermal pressure roller motor 129a (see <FIG>) is an example of the drive unit <NUM>.

A description is now given of the configuration of the sheet laminator <NUM>.

<FIG> is a flowchart of a stopping process of the thermal pressure roller pair according to a first embodiment of the present disclosure.

In the present embodiment, the controller <NUM> of the sheet laminator <NUM> determines the state of the thermal pressure roller pair <NUM> based on the detection result of the temperature of the thermal pressure roller pair <NUM> with the thermistors <NUM>, and selects an immediate stop of the thermal pressure roller pair <NUM> or a stop of the thermal pressure roller pair <NUM> after the rotation operation based on the state of the thermal pressure roller pair <NUM>. By executing the appropriate stop control based on the temperature of the thermal pressure roller pair <NUM> after the stopping operation is performed on the thermal pressure roller pair <NUM> in the sheet laminator <NUM>, the thermal pressure roller pair <NUM> can be stopped without being damaged.

More specifically, when the stopping operation is performed on the thermal pressure roller pair <NUM> in step S101, in other words, when an abnormal condition occurs, the controller <NUM> immediately turns off the heaters <NUM> in consideration of safety in step S102. When an abnormal condition occurs, the heaters <NUM> are immediately turned off. The controller <NUM> causes the thermal pressure roller pair <NUM> to rotate at an appropriate stop control of the thermal pressure roller pair <NUM> to safely stop the sheet laminator <NUM>. Then, in step S103, the roller temperature of the thermal pressure roller pair <NUM> at the immediate turnoff of the heaters <NUM> is detected with the thermistors <NUM>, and the controller <NUM> determines whether the roller temperature of the thermal pressure roller pair <NUM> is equal to or smaller than a first predetermined temperature T1 that is <NUM> to determine whether the thermal pressure roller pair <NUM> is rotated or not.

When the roller temperature of the thermal pressure roller pair <NUM> at the immediate turnoff of the thermal pressure roller pair <NUM> is equal to or smaller than the first predetermined temperature T1 that is <NUM> (YES in step S103), the controller <NUM> immediately stops the rotation of the thermal pressure roller pair <NUM> in step S108.

On the other hand, when the roller temperature of the thermal pressure roller pair <NUM> at the immediate turnoff of the thermal pressure roller pair <NUM> is greater than the first predetermined temperature T1 that is <NUM> (NO in step S103), the controller <NUM> determines whether the roller temperature of the thermal pressure roller pair <NUM> is equal to or lower than a second predetermined temperature T2 that is <NUM> in step S <NUM>. The relation of the first predetermined temperature T1 and the second predetermined temperature T2 is expressed as the second predetermined temperature T2 > the first predetermined temperature T1, in other words, the second predetermined temperature T2 is greater than the first predetermined temperature T1.

When the roller temperature is equal to or lower than the second predetermined temperature T2 that is <NUM> (YES in step S104), the controller <NUM> sets the rotation time of the thermal pressure roller pair <NUM> to a first rotation time TA that is <NUM> seconds in step S105. On the other hand, when the roller temperature is greater than the second predetermined temperature T2 that is <NUM> (NO in step S104), the controller <NUM> sets the rotation time of the thermal pressure roller pair <NUM> to a second rotation time TB that is <NUM> seconds in step S106. In other words, the thermal pressure roller pair <NUM> is stopped after the rotation operation. The relation of the first rotation time TA and the second rotation time TB is expressed as the second rotation time TB > the first rotation time TA, in other words, the second rotation time TB is greater than the first rotation time TA. The minimum duration time (rotation time) of the rotation operation of the thermal pressure roller pair <NUM> is determined based on the state when the sheet laminator <NUM> is stopped. By so doing, the controller <NUM> causes the thermal pressure roller pair <NUM> not to rotate more than necessary and can reduce the stopping operation time.

Then, the controller <NUM> determines whether the set time (i.e., <NUM> seconds or <NUM> seconds) has elapsed in step S107. When the set time has not elapsed (NO in step S107), step S107 is repeated until the set time elapses. When the set time has elapsed (YES in step S107), the rotation of the thermal pressure roller pair <NUM> is stopped in step S108, and the stopping process is completed.

The amounts of the first predetermined temperature T1, the second predetermined temperature T2, the first rotation time TA, and the second rotation time TB can be changed as appropriate.

<FIG> is a flowchart of a stopping process of the thermal pressure roller pair according to a second embodiment of the present disclosure.

In the present embodiment, the controller <NUM> of the sheet laminator <NUM> determines the state of the thermal pressure roller pair <NUM> based on the detection result of the temperature of the thermal pressure roller pair <NUM> with the thermistors <NUM> and the determination of heater lighting amount (obtained by multiplying time by lighting percentage) by the controller <NUM>. Then, the controller <NUM> selects an immediate stop of the thermal pressure roller pair <NUM> or a stop of the thermal pressure roller pair <NUM> after the rotation operation based on the state of the thermal pressure roller pair <NUM>. Instead of the detection of the temperature of the thermistors <NUM>, the controller <NUM> may determine the state of the thermal pressure roller pair <NUM> based on the heater lighting amount. By executing an appropriate stop control over the thermal pressure roller pair <NUM> based on the heater lighting amount immediately before the stop of the sheet laminator <NUM>, the thermal pressure roller pair <NUM> can be stopped without being damaged. Since this operation does not depend on the sensor information (i.e., thermistor information), the sheet laminator <NUM> can be safely stopped even at the time of the abnormal condition of the sensor.

More specifically, when the stopping operation is performed on the thermal pressure roller pair <NUM> in step S201, in other words, when an abnormal condition occurs, the controller <NUM> immediately turns off the heaters <NUM> in consideration of safety in step S202. When an abnormal condition occurs, the heaters <NUM> are immediately turned off. The controller <NUM> causes the thermal pressure roller pair <NUM> to rotate at an appropriate stop control of the thermal pressure roller pair <NUM> to safely stop the sheet laminator <NUM>. Then, in step S203, the roller temperature of the thermal pressure roller pair <NUM> at the immediate turnoff of the heaters <NUM> is detected with the thermistors <NUM>, and the controller <NUM> determines whether the roller temperature of the thermal pressure roller pair <NUM> is equal to or smaller than the first predetermined temperature T1 that is <NUM> and equal to or smaller than a heater lighting amount D1 that is 4800J to determine whether the thermal pressure roller pair <NUM> is rotated or not.

<FIG> is a graph of the heater lighting amount obtained by multiplying a time by a heater lighting percentage.

As illustrated in <FIG>, the heater lighting amount indicates the heater lighting percentage per <NUM> seconds that is equal to a predetermined time t from the immediate turnoff of the heaters at occurrence of the stopping operation. In other words, the heater lighting amount D is obtained by multiplying a time t by a heater lighting percentage. The heater lighting amount D is expressed as the heater lighting amount D = time t × heater lighting percentage.

When the controller <NUM> determines that the condition of step S203 is satisfied, in other words, the roller temperature of the thermal pressure roller pair <NUM> is equal to or smaller than the first predetermined temperature T1 that is <NUM> and equal to or smaller than a heater lighting amount D1 that is 4800J (YES in step S203), the controller <NUM> causes the thermal pressure roller pair <NUM> to immediately stop the rotation in step S211.

On the other hand, when the controller <NUM> determines that the condition of step S203 is not satisfied, in other words, the roller temperature of the thermal pressure roller pair <NUM> is greater than the first predetermined temperature T1 that is <NUM> and greater than the heater lighting amount D1 that is 4800J (NO in step S203), the controller <NUM> determines whether the roller temperature of the thermal pressure roller pair <NUM> is equal to or smaller than the second predetermined temperature T2 that is <NUM> in step S204. The relation is expressed as the second predetermined temperature T2 > the first predetermined temperature T1.

When the roller temperature is equal to or smaller than the second predetermined temperature T2 that is <NUM> (YES in step S204), the controller <NUM> sets the rotation time of the thermal pressure roller pair <NUM> to the first rotation time TA that is <NUM> seconds in step S205. On the other hand, when the roller temperature is greater than the second predetermined temperature T2 that is <NUM> (NO in step S204), the controller <NUM> sets the rotation time of the thermal pressure roller pair <NUM> to the second rotation time TB that is <NUM> seconds in step S206 (the second rotation time TB > the first rotation time TA). In other words, the thermal pressure roller pair <NUM> is stopped after the rotation operation. The minimum duration time (rotation time) of the rotation operation of the thermal pressure roller pair <NUM> is determined based on the state when the sheet laminator <NUM> is stopped. By so doing, the controller <NUM> causes the thermal pressure roller pair <NUM> not to rotate more than necessary and can reduce the stopping operation time.

Then, in step S207, the controller <NUM> determines whether the roller temperature of the thermal pressure roller pair <NUM> at the immediate turnoff of the heaters <NUM> is equal to or smaller than the first predetermined temperature T1 that is <NUM> and equal to or smaller than the heater lighting amount D1 that is 4800J and sets the roller rotation speed depending on the detection result. By changing the rotational speed of the thermal pressure roller pair <NUM> based on the state of the thermal pressure roller pair <NUM> at the stop of the sheet laminator <NUM>, the temperature of the thermal pressure roller pair <NUM> is quickly lowered and the waiting time of the user can be reduced.

When the controller <NUM> determines the condition of step S207 is satisfied, in other words, the roller temperature of the thermal pressure roller pair <NUM> at the immediate turnoff of the heaters <NUM> is equal to or smaller than the first predetermined temperature T1 that is <NUM> and equal to or smaller than the heater lighting amount D1 that is 4800J (YES in step S207), the controller <NUM> changes the rotational speed of the thermal pressure roller pair <NUM> to a first rotational speed SA that is <NUM>/sec in step S208. On the other hand, when the controller <NUM> determines the condition of step S207 is not satisfied, in other words, the roller temperature of the thermal pressure roller pair <NUM> at the immediate turnoff of the heaters <NUM> is greater than the first predetermined temperature T1 that is <NUM> and greater than the heater lighting amount D1 that is 4800J (NO in step S207), the controller <NUM> changes the rotational speed of the thermal pressure roller pair <NUM> to a second rotational speed SB that is <NUM>/sec in step S209 (the second rotational speed SB > the first rotational speed SA).

Then, the controller <NUM> determines whether the set time (i.e., <NUM> seconds or <NUM> seconds) has elapsed in step S210. When the set time has not elapsed (NO in step S210), step S210 is repeated until the set time elapses. When the set time has elapsed (YES in step S210), the rotation of the thermal pressure roller pair <NUM> is stopped in step S211, and the stopping process is completed.

The amounts of the first predetermined temperature T1, the second predetermined temperature T2, the first rotation time TA, the second rotation time TB, the first rotational speed SA, the second rotational speed SB, and the heater lighting amount D1 can be changed as appropriate.

In addition, the set thresholds of the respective parameters may be increased, for example, the first predetermined temperature T1, the second predetermined temperature T2, a third predetermined temperature T3 or more, to perform control having more detailed conditions.

As described above, according to the sheet laminator of an embodiment of the present disclosure, when an abnormal condition occurs, the power supply to the fixing heater is immediately turned off, and the immediate stop of the thermal pressure roller pair <NUM> or the stop of the thermal pressure roller pair <NUM> after the rotation operation is selected based on the state of the thermal pressure roller pair <NUM>. By so doing, the stopping operation time can be reduced and damage on the rollers such as deformation of the thermal pressure roller pair in the nip region can be prevented. When the thermal pressure roller pair <NUM> is rotated, the stopping operation time is reduced by changing the roller rotation time or the roller rotation speed depending on the roller temperature or the heater lighting percentage, so that the recovery time to the subsequent print job can be shortened.

The present disclosure is not limited to specific embodiments described above, and numerous additional modifications and variations are possible in light of the teachings within the technical scope of the appended claims. It is therefore to be understood that, the disclosure of this patent specification may be practiced otherwise by those skilled in the art than as specifically described herein.

The effects described in the embodiments of this disclosure are listed as the examples of preferable effects derived from this disclosure, and therefore are not intended to limit to the embodiments of this disclosure.

The embodiments described above are presented as an example to implement this disclosure. The embodiments described above are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, or changes can be made, these embodiments and their variations being included in the scope of this disclosure and included in the scope of the invention as long as within the meaning of the appended claims.

Claim 1:
A sheet laminator (<NUM>) comprising:
a fuser pressure member (<NUM>), being a pair of rollers, configured to thermally fix a two-ply sheet (S) and a sheet medium (P) inserted between two sheets of the two-ply sheet (S);
a heater (<NUM>) configured to heat the fuser pressure member (<NUM>);
a driver (<NUM>, 129a) configured to rotate the fuser pressure member (<NUM>); and
a controller (<NUM>) configured to, in response to a pause of a rotation of the fuser pressure member (<NUM>),
turn off a power supply to the heater (<NUM>); and
perform one of:
immediately stopping the rotation of the fuser pressure member (<NUM>); or
rotating the fuser pressure member (<NUM>) and stopping the rotation of the fuser pressure member (<NUM>) after the rotation of the fuser pressure member (<NUM>),
based on a state of the fuser pressure member (<NUM>).