Blanket replacement system and method thereof

Blanket replacement systems and methods useable with an image forming apparatus are provided herein. The blanket replacement system removes the blanket from the image transfer member and attaches the blanket to the image transfer member. The blanket replacement system includes a frame member, an engagement motor, and a rotation motor. The frame member holds a blanket having a lead edge portion on one edge and a trail edge portion on an opposing edge. The frame member further includes a lead edge clamp unit and a trail edge clamp unit that holds the lead edge and trail edge portions of the blanket and engages with an image transfer member. The engagement motor engages with the frame member and moves the frame member laterally in relation to the engagement motor. The rotation motor is connected to the engagement motor and rotates the engagement motor and the frame member.

BACKGROUND

Image forming apparatuses, such as liquid electrophotography (LEP) systems, form images on media. Liquid electrophotography systems include a fluid applicator unit, a photoconductive member, an image transfer member, and an impression member. The image formed on the photoconductive member is transferred to the image transfer member, and then is provided to the media. An impression member may be used to transfer the image from the image transfer member to the media.

DETAILED DESCRIPTION

A roller system of an image forming apparatus includes an image transfer member, such as an intermediate transfer member (ITM), and a roller device, such as an impression drum. The image transfer member has a replaceable blanket attached to the outer surface to receive the fluid image and transfer the fluid image to a media. The blanket includes an outer surface with rubber to receive the fluid, such as ink, and fabric opposing the outer surface to hold the blanket to the image transfer member. The blanket is replaced on a regular basis during normal use. Replacement of the blanket usually occurs manually; however the location of the image transfer member makes it difficult to access and replace the blanket manually. Moreover, manual replacement of the blanket may take a long time and may result in mistakes, leading to loss of profits due to more frequent replacement of the blanket and longer downtime of the image forming apparatus.

In examples, blanket replacement systems and methods are provided to replace the blanket. The blanket replacement system includes a frame member, an engagement motor, and a rotation motor. The frame member holds a blanket having a lead edge portion on one edge and a trail edge portion on an opposing edge. The frame member further includes a lead edge clamp unit and a trail edge clamp unit that holds the lead edge and trail edge portions of the blanket and engages with an image transfer member. The engagement motor engages with the frame member and moves the frame member laterally in relation to the engagement motor. The rotation motor is connected to the engagement motor and rotates the engagement motor and the frame member. The blanket replacement system removes the blanket from the image transfer member and attaches the blanket to the image transfer member using a blanket device that replaces manual replacement by a user and provides for a quicker and more accurate replacement of the blanket.

FIG. 1is a schematic view illustrating an image forming apparatus, such as a liquid electrophotography system (LEP), according to an example. The LEP100includes an image forming unit10that receives a media S from an input unit11and outputs the media S to an output unit12. The image forming unit10includes a photoconductive member13on which images can be formed. The photoconductive member14may be charged with a suitable charger (not illustrated), such as a charge roller. Portions of the outer surface of the photoconductive member13that correspond to the features of the image can be selectively discharged by a laser writing unit14to form an electrostatic and/or latent image thereon.

Referring toFIG. 1, the LEP100also includes an applicator unit15to apply ink, such as a liquid toner, for example, ElectroInk, trademarked by Hewlett-Packard Company, to the electrostatic and/or latent image on the photoconductive member13. The ink in the ink applicators is monitored for proper high field conductivity. The ink is applied to the photoconductive member13to form a fluid image to be transferred to a roller system, including an image transfer member16, such as an intermediate transfer member (ITM) and a roller device17, such as an impression member. The image transfer member16has a replaceable blanket18attached thereto with a rubber side to receive the fluid image and a fabric side to hold the blanket18to the image transfer member16.

The fluid image is transferred to the media S using the image transfer member16and the blanket18. The blanket18receives the fluid image from the photoconductive member13, the image transfer member16heats the fluid image, and the blanket18transfers the fluid image to the media S. During the transfer of the fluid image from the image transfer member16to the media S, the media S is pinched between the image transfer member16and the roller device17. Once the fluid image has been transferred to the media S, the media S can be transported to the output unit12. When the blanket18is replaced, a blanket replacement system20may be activated to replace the blanket18. For example, the blanket18may be replaced by the blanket replacement system20between a specified number of printed pages and/or print jobs.

FIG. 2is a block diagram illustrating a blanket replacement system20according to an example. The blanket replacement system20is useable with an image forming apparatus10. The blanket replacement system20includes a frame member22, an engagement motor24, and a rotation motor26.FIG. 3illustrates a perspective view of the frame member22and the blanket18according to an example.

Referring toFIGS. 2-3, the frame member22holds a blanket18. The blanket18has a lead edge portion31on one edge and a trail edge portion32on an opposing edge. The frame member22includes at least one lead edge clamp unit33and at least one trail edge clamp unit34, formed, for example, using a spring. The lead edge clamp unit33holds the lead edge portion31of the blanket18. For example, there may be two lead edge clamp units33a,33b, one holding down each edge of the lead edge portion31of the blanket18. The trail edge clamp unit34holds the trail edge portion32of the blanket18. For example, there may be two trail edge clamp units34a,34b, one holding down each edge of the trail edge portions32of the blanket18.

The lead edge clamp unit33and the trail edge clamp unit34engage with the image transfer member16to perform at least one of removal of the blanket18from the image transfer member16and attachment of the blanket18to the image transfer member16. The frame member22also engages with the engagement motor24using, for example, a set of frame gears35to move the frame member22laterally in relation to the engagement motor24.

FIG. 4illustrates a schematic view of the blanket replacement system20ofFIG. 2according to an example. A portion of the blanket replacement system20is represented in a dotted line box including the frame member22, the engagement motor24, and the rotation motor26, which form a blanket device30that operates in a synchronized manner.

The engagement motor24engages with the frame member22and moves the frame member22laterally in relation to the engagement motor24. The engagement motor24and the frame member22engage with one another using, for example, the set of frame gears35and an engagement pinion40that enable lateral motion of the frame member22with respect to the engagement motor24. For example, the engagement motor24moves the lead edge clamp unit33and the trail edge claim unit34towards and away from the image transfer member16. The engagement motor24is utilized for movements of the frame member22to enable engagement between the frame member22and the image transfer member18. For example, the at least one lead edge clamp unit33also engages with at least one lead edge holding member41of an image transfer member16of the image forming apparatus10. At least one of the trail edge clamp units34engage with at least one trail edge holding member42of the image transfer member16.

In contrast, the rotation and the angular position of the frame member22are controlled by the rotation motor26. The engagement motor24and the rotation motor26work in combination and/or synchronization to position the frame member22. The rotation motor26is connected to the engagement motor24. The rotation motor26rotates the engagement motor24and the frame member22. For example, the rotation motor26rotates while the engagement motor24and the frame member22remain fixed. In operation, the rotation motor26, the engagement motor24, and the frame member22rotate as one object to roll the blanket18onto the frame member22and/or unroll the blanket18from the frame member22.

As illustrated inFIG. 3, the blanket device30may include two frame members22such that there is a frame member22on each side of the blanket18. Similarly, the blanket device30may also include two engagement motors24and two rotation motors26, such as one on each side of the blanket18. The engagement motor24and the rotation motor26may further include encoders to measure and calibrate the rotation.

The blanket replacement system20may further include a transport unit43connected to the blanket device30. The transport unit43may include a rail44and a timing belt45that moves the blanket device30towards and away from the image transfer member16. The timing belt45may be controlled by a transport motor46and a transport encoder47that measures the angular position of the transport motor46. For example, the transport unit43may move the blanket device30between a holding position A and an active position B and then between the active position B and a working position C, via the rail44. In the working position C, the frame member22may engage with the image transfer member16to remove and/or attach the blanket18.

FIG. 5is a schematic view illustrating removal of the blanket18using the blanket replacement system20ofFIG. 2according to an example. The blanket replacement system20positions the blanket device30in proximity to the image transfer member16, for example in working position C ofFIG. 4. For example, the frame member22is rotated into position by the rotation motor26. The rotation motor26rotates R1to position the frame member22in relation to the image transfer member16, such that the rotation motor may rotate by an angle α. The engagement motor24rotates R2to laterally move the lead edge clamp unit33and the frame member22towards the image transfer member16. The engagement motor24, for example, is rotated by an angle β to move the frame member22laterally into position.

After the frame member22is moved laterally and rotationally into position, the frame member22engages the lead edge clamp unit33and the lead edge holding member41to connect the lead edge clamp unit33to the lead edge portion31of the blanket18. The lead edge portion31of the blanket18attaches to the lead edge clamp unit33. The engagement between the lead edge clamp unit33and the lead edge portion31releases the lead edge portion31of the blanket18from the image transfer member16by releasing the lead edge holding member41from a closed position41ato an open position41b.

The rotation of the frame member22by the rotation motor26separates the blanket18from the image transfer member16. The lead edge clamp unit33collects the blanket18as the frame member22rotates. Additionally, image transfer member16also rotates in synchronization with the frame member22to remove the blanket18from the image transfer member16. Tension may be formed in the blanket18between the image transfer member16and frame member22to release and collect the blanket18.FIG. 6below illustrates an example of the tension. The engagement of the trail edge clamp unit34and the trail edge holding member42releases the trail edge portion32of the blanket18from the image transfer member16by, for example, opening the trail edge holding member42from a closed position42ato an open position42b. The blanket18is attached to the frame member22and carried by the blanket device30to active position B ofFIG. 4. Once the blanket18is in active position B, a user may manually remove the blanket18from the frame member22and replace it with a new blanket18.

Referring toFIG. 5, the blanket replacement system20further includes a sensor unit. The sensor unit includes at least one of a lead edge sensor51, a trail edge sensor52, a transport sensor53, a rotation encoder54, and an engagement encoder55. The lead edge sensor51and the trail edge sensor52may each include two sensors positioned on the lead edge clamp unit33and the trail edge clamp unit34of the frame member22. For example, the lead edge sensors51may position the lead edge clamp unit33in proximity to the lead edge holding member41of the image transfer member16, and the trail edge sensors52may positioned the trail edge clamp unit34in proximity to the trail edge holding member42of the image transfer member16. The engagement motor24and the rotation motor26may be used to laterally move and rotate the frame member22into position using the sensors.

The transport sensor53is illustrated to include two transport sensors53a,53blocated on opposite ends of the rail44; however, any number of transport sensors53may be positioned within the transport unit43, such as along the rail44and/or timing belt45. The transport sensors53a,53bare positioned along the transport unit43to position and/or monitor the blanket device30along the rail44. The rotation encoder54measures the first angular position α of the rotation motor26. The engagement encode55measures the second angular position β of the engagement motor24. For example, the rotation motor26and/or the engagement motor24may control torque using positioning sensors to verify the position of the blanket device30. The frame member22may also include micro-switches that work with the lead edge sensor51and the trail edge sensor52to sense the position of the lead edge clamp unit33and the trail edge clamp unit34on each of the edges.

FIG. 6is a schematic view illustrating attachment of the blanket18using the blanket replacement system ofFIG. 2according to an example. The blanket18is attached to the blanket device30, for example, the blanket18may be manually attached to the frame member22. The attachment includes the lead edge portion31of the blanket18being attached to the lead edge clamp unit33and the trail edge portion32of the blanket18being attached to the trail edge clamp unit34. Once the blanket18is attached to the frame member22, the blanket device30is moved along the transport unit43from the active B position to the working C position.

The blanket replacement system20engages the lead edge clamp unit33and the lead edge holding member41to attach the lead edge portion31of the blanket18to the image transfer member16. For example, the frame member22engages with the lead edge holding member41and inserts the lead edge portion31of the blanket18onto the image transfer member16. The lead edge holding member41moves to a closed position41afrom an open position41bto hold the blanket18thereon.

The rotation motor26rotates the frame member22to position the blanket18onto the image transfer member16. For example, the rotation motor26and the image transfer member16may move in opposite directions, such as the rotation motor26moving counter clockwise R1and the image transfer member16moving clockwise R3to attach the blanket18to the image transfer member16. During the rotation of the rotation motor26and the image transfer member16, the tension61holds the blanket18against the image transfer member16. Moreover, the blanket replacement system20remains in proximity to the image transfer member16, but at varying locations62. The movement of the image transfer member16allows the blanket18to be positioned onto the image transfer member16using the blanket replacement system20. After the blanket18is attached to the image transfer member16, the trail edge clamp unit34and the trail edge holding member42engage to attach a trail edge portion32of the blanket18to the image transfer member16. The engagement includes the trail edge clamp unit34engaging with the trail edge holding member36to connect the trail edge portion32of the blanket18to the image transfer member16and hold the blanket18in position with the trail edge holding member42moving to a closed position42afrom an open position42b.

Referring toFIG. 6, the blanket replacement system20may further include a paper collection device63having a collection motor64to rotate in synchronization with the rotation motor26using a collection encoder65to measure the angular position of the collection motor64. For example, the collection motor64may rotate three times for every one rotation of the rotation motor26. The collection device63also includes a collection unit66to collect a blanket paper67separated from the blanket18as the blanket18is attached to the image transfer member16.

A control algorithm may be used to assist with removing and/or attaching the blanket18based on the tension61. For example, in a tension control algorithm, the tension of blanket18or blanket paper67is determined by setting the current of the applicable motors, such as the engagement motor24, the rotation motor26, and/or the collection motor64. The equation for torque (T) may be equal to current multiplied by a motor factor. Alternatively, the equation for torque may be equal to radius of the force multiplied by substrate tension, where the substrate tension is determined by the current setting, such that the current setting is force equal to current multiplied by a motor factor and divided by the radius of the force. A position algorithm may also be used in combination with the control algorithm or alone. The position algorithm controls the blanket18at different timing and/or stages. For example, when the tension61is sensed and controlled by the engagement motor24, the rotation motor26, and/or the collection motor64, the position control may be performed by the encoders.

FIG. 7illustrates a method700to remove a blanket from an image transfer member according to an example. In block72, the method700positions a blanket device adjacent to the image transfer member. The blanket device is positioned by manual rotation of the blanket device from a storage position to an active position. In the active position, the blanket device is transported towards and away from the image transfer member using a transport unit including a timing belt and a rail.

The blanket device includes a frame member, an engagement motor, and a rotation motor. The frame member holds a blanket. The blanket having a lead edge portion on one edge and a trail edge portion on an opposing edge. The frame member includes at least one lead edge clamp unit and at least one trail edge clamp unit that engage with the image transfer member. The engagement motor engages with the frame member and moves the frame member laterally in relation to the engagement motor. The rotation motor is connected to the engagement motor and rotates the engagement motor and the frame member.

In block74, at least one lead edge clamp unit and a lead edge holding member of the image transfer member engage. The engagement releases the lead edge portion of the blanket from a lead edge holding member of the image transfer member. The rotation of the engagement motor and the angular position of the image transfer member are synchronized to enable engagement therebetween. The frame member is rotated by the rotation member in block76to separate the blanket from the image transfer member. The frame member and the image transfer member are both rotated in synchronization to position the blanket onto the image transfer member. The rotation also provides tension between the image transfer member and the frame member to remove the blanket from the image transfer member. In block78, the at least one lead edge clamp unit and a trail edge holding member of the image transfer member engage to release the trail edge portion of the blanket to the image transfer member. The method700further includes sensing a position of the blanket device using a set of sensors distributed on the blanket device and the blanket replacement system and an encoder on at least one of the rotation motor and the engagement motor.

FIG. 8illustrates a method800to attach a blanket to an image transfer member according to an example. In block82, the method800positions a blanket device adjacent to the image transfer member. The blanket device is positioned by manual rotation of the blanket device from a storage position to an active position. In the active position, the blanket device is transported towards and away from the image transfer member using a transport unit including a timing belt and a rail.

The blanket device includes a frame member, an engagement motor, and a rotation motor. The frame member holds a blanket. The blanket having a lead edge portion on one edge and a trail edge portion on an opposing edge. The frame member includes at least one lead edge clamp unit and at least one trail edge clamp unit that engage with the image transfer member. The engagement motor engages with the frame member and moves the frame member laterally in relation to the engagement motor. The rotation motor is connected to the engagement motor and rotates the engagement motor and the frame member.

The method800engages at least one lead edge clamp unit and a lead edge holding member of the image transfer member, in block84. The engagement attaches the lead edge portion of the blanket to a lead edge holding member of the image transfer member. The rotation of the engagement motor and the angular position of the image transfer member are synchronized to enable engagement therebetween. In block86, the frame member is rotated with the rotation motor to position the blanket onto the image transfer member. The frame member and the image transfer member are both rotated in synchronization to position the blanket onto the image transfer member. Moreover, the blanket is held in tension between the image transfer member and the frame member during rotation. The at least one lead edge clamp unit and a trail edge holding member of the image transfer member engage with one another to attach the trail edge portion of the blanket to the image transfer member, in block88.

The method800includes sensing a position of the blanket device using a set of sensors distributed on the blanket device and the blanket replacement system and an encoder on at least one of the rotation motor and the engagement motor. The method800further includes collection of a blanket paper attached to the blanket paper with a paper collection device. The paper collection device includes a collection motor that rotates in synchronization with the rotation motor as the blanket is attached to the image transfer member.

The present disclosure has been described using non-limiting detailed descriptions of examples thereof and is not intended to limit the scope of the present disclosure. It should be understood that features and/or operations described with respect to one example may be used with other examples and that not all examples of the present disclosure have all of the features and/or operations illustrated in a particular figure or described with respect to one of the examples. Variations of examples described will occur to persons of the art. Furthermore, the terms “comprise,” “include,” “have” and their conjugates, shall mean, when used in the present disclosure and/or claims, “including but not necessarily limited to.”

It is noted that some of the above described examples may include structure, acts or details of structures and acts that may not be essential to the present disclosure and are intended to be exemplary. Structure and acts described herein are replaceable by equivalents, which perform the same function, even if the structure or acts are different, as known in the art. Therefore, the scope of the present disclosure is limited only by the elements and limitations as used in the claims.