The instant invention relates to folding machines and, more particularly, to a folding machine having a smart nip for reducing noise within the folding machine during operation thereof.

Folding machines are well known and can be configured to permit the folding of a sheet of paper into one of several different type folds such as a Z-fold or a C-fold. These conventional folding machines include one or more buckle chutes into which sheets are fed by a plurality of feeding and folding rollers. The sheets are fed into a particular buckle chute until the lead edge abuts a fixed backstop, which arrests further movement of the sheet within the buckle chute. However, since a portion of the sheet still remains outside the buckle chute, the continued rotation of the feeding and folding rollers causes the sheet to form a buckle which is directed into the nip of another set of feeding and folding rollers thereby forming the desired fold. If an additional fold is required, the same process described above is accomplished utilizing another buckle chute and additional feeding and folding rollers as described in detail in numerous prior art documents.

A significant problem with the conventional folding machines discussed above is that they are excessively noisy. That is, in high-speed folders the sheets of paper strike the backstop at a high velocity causing noise due to the physical impact between the paper and the backstop. Moreover, since the buckle is formed in a very sudden manner, bending waves are quickly created within the paper sheets that produce a significant amount of noise. These noises can rise to significant levels and are certainly an inconvenience to users, particularly if the folding machine is located in an office environment where ongoing business is being conducted.

In addition to the above, many conventional folding machines require the backstops to be manually adjusted when a different type of fold is required or the size of the paper changes. This too is a big inconvenience for the user.

Accordingly, what is needed is a folding machine having reduced noise levels as compared to prior art folding devices and which permits the user to more efficiently set up the folding machine when the type of fold or paper size changes.

It is an object of the invention to correct the deficiencies of the prior art folding machines discussed above. This object is met by providing a method for folding a media in a folding machine including the steps of moving the media in the folding machine using at least one feeding/folding roller combination; transporting the media into a buckle chute; decelerating the media within the buckle chute using a smart nip roller configuration while continuing to move the media with the feeding/folding roller combination to form a buckle in the media without the use of a backstop in the buckle chute; and pulling the media from the buckle chute and the feeding/folding roller combination to form a folded panel in the media.

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate a presently preferred embodiment of the invention, and together with the general description given above and the detailed description of the preferred embodiment given below, serve to explain the principles of the invention.

• Figures 1-8 are a schematic representation showing a single media at various stages as it is being processed through the inventive folding machine;
• Figure 9 shows the velocity profiles for the rollers of the inventive folding machine as it corresponds to Figures 1-8; and
• Figure 10 shows structure for a second embodiment.

Figures 1-8, taken together, show the various stages that an 8.5 inch by 11 inch sheet of paper goes through as it is processed within the inventive folding machine 1 into a C-fold configuration. Moreover, Figure 9 shows the velocity profiles for each of the rollers of the folding machine 1 over time relative to the descriptions set forth below in connection with Figures 1-8.

In Figure 1, the media 3 (in this case the above referred to sheet of paper) enters into the nip of first feeding and folding rollers 5 and 7. First feeding and folding rollers 5, 7 are driven into rotation at a velocity "V1" through their interaction with second feeding and folding rollers 9, 11. In the preferred embodiment shown, roller 11 is controlled by a microcontroller 13 (Shown only in Figure 1 for ease of explanation but is applicable to all of Figures 1-8) in a conventional manner and through a conventional drive system (not shown) to move at a linear velocity V1 at its outer periphery. This in turn causes rollers 9, 7, and 5 to rotate at the same linear velocity V1. The microcontroller 13 includes a central processing unit 15 for executing the programs described herein and stored in a ROM 17 utilizing a RAM 19. Accordingly, as the media 3 enters the nip of rollers 5, 7 it is driven at the constant velocity V1 toward a first buckle chute 21. Mounted in a conventional manner for rotation along the first buckle chute 21 are a first pair of smart nip rollers 23, 25. The smart nip rollers 23, 25 are mounted such that the nip defined therebetween extends within the first buckle chute 21 as shown. Thus, as the media 3 enters the buckle chute 21 it is ingested into the nip of the smart nip rollers 23, 25. The smart nip rollers 23, 25 are controlled by the microcontroller 13 through a conventional drive train (not shown) to have a peripheral linear velocity V1 (Figure 2). In the preferred embodiment the smart nip roller 25 is the drive roller while the smart nip roller 23 is the driven roller. As further shown in Figure 2, the smart nip rollers 23, 25 together with the feeding/folding rollers 5, 7 feed the media 3 into the buckle chute 21 at the constant velocity V1 until a sensor 27 detects the lead edge of the media 3. The sensor 27 is shown as a conventional through-beam sensor but can be any suitable sensor capable of detecting the presence of the leading and trailing edges of the media 3. Upon the detection of the lead edge of the media 3 (or alternatively a predetermined short time thereafter), the microcontroller 13, based upon a lead edge detection signal received from sensor 27, begins to decrease the peripheral linear velocity of the smart nip rollers 23, 25 at a specific rate to achieve the desired type of fold for the specified media 3. In the preferred embodiment the desired fold is a first fold of a C-fold configuration and the deceleration rate is determined such that at zero velocity the media 3 has been fed into the buckle chute 21 a distance approximately equal to two thirds of the length of the media 3. It is to be noted that one skilled in the art can easily determine the required deceleration rate based on the fold type, paper size, and the velocity V1.

With reference to Figures 3 and 9, the deceleration of the rollers 23 and 25 continues until their peripheral linear velocity reaches zero. At this point in time, a buckle 29 has gradually been formed in the media 3 since the rollers 5,7 continued to feed the media 3 at velocity V1 while the smart nip rollers 23, 25 were decelerating. However, since there is no impact with a mechanical stop and the buckle 29 is gradually formed over time versus very suddenly, any noise associated with the formation of the buckle 29 is greatly reduced as compared to the prior art devices which used a mechanical backstop to form the buckle. Once the smart nip rollers 23, 25 reach zero linear velocity such that the media 3 has moved into the buckle chute 21 approximately the distance equal to two thirds of its overall length, the microcontroller 13 causes the smart nip rollers 23, 25 to accelerate in the opposite direction up to the velocity V1 moving the media 3 therewith out of the buckle chute 21. When the smart nip rollers 23, 25 have accelerated to the velocity V1, the buckle 29 is about to be ingested into the nip of rollers 7 and 9 to form the first fold panel as shown in Figure 4. The smart nip rollers 23, 25 continue to drive the media 3 at velocity V1 together with the rollers 7 and 9 such that the media 3, with its first fold, moves toward a second buckle chute 31. When the trailing edge (previously the lead edge) of the media 3 is again detected by the sensor 27, the microcontroller 13 after a short time delay (to allow the trailing edge of the media 3 to clear the smart nip rollers 23 and 25) begins accelerating the smart nip rollers 23, 25 in the reverse direction up to the velocity V1 so that the smart nip rollers 23, 25 are ready to receive the next incoming media 3.

Referring to Figure 5, the media 3 with its first fold is transported into a second buckle chute 31 at the velocity V1 by the rollers 7, 9 and a second set of smart nip rollers 33, 35 which are identical to the smart nip rollers 23, 25 and are controlled and driven independently but in the same manner as smart nip rollers 23, 25 by microcontroller 13 and an appropriate drive system (not shown). A second sensor 37, which can be the same as sensor 27, detects the lead edge of the media 3 within buckle chute 31 and sends a signal to microcontroller 13 indicative that such is the case. Microcontroller 13 upon receipt of the sensor signal controls the smart nip rollers 33, 35 in the same manner as that described above for rollers 23, 25 in order to create the second fold in the media 3 to complete the C-fold. The only difference is that for the second fold the deceleration of the smart nip rollers 33, 35 is controlled to ensure that the media 3 only enters the second buckle chute 31 one third of the total length of the unfolded media 3 as shown in Figure 6. This is accomplished by having a deceleration rate that is twice as great as that associated with smart nip rollers 23, 25. Once the smart nip rollers 33, 35 have reached zero velocity, the microcontroller 13 accelerates the rollers 33, 35 in the opposite direction back to a velocity of V1. The second sensor 37 will then detect the trail edge of the media 3 and send a signal to the microcontroller 13 indicative of such detection. The microcontroller 13 then once again reverses the rotation of the smart nip rollers 35, 37 when the trail edge of the media has left the nip of the smart nip rollers 33, 35 as shown in Figure 7. The smart nip rollers are then accelerated back to a velocity V1 to await ingestion of the next media 3 with a first fold therein. Finally, in Figure 8, the completely C-folded media 3 is ejected from the folding machine 1 by the rollers 9 and 11.

While the preferred embodiment has been described with respect to a C-fold operation, one possessing ordinary skill in the art will recognize that it can be applied to any type of fold configuration with the deceleration and acceleration parameters as well as the number of feeding/folding rollers and smart nip rollers being dependent upon the fold type, the paper size, and the speed of paper processing. Moreover, the particular drive configurations can be varied and the smart nip rollers can be placed just prior to the buckle chutes. Additionally, in an alternate embodiment the feeding/folding rollers can be decelerated and accelerated substantially simultaneously with the smart nip rollers to achieve the desired fold with even less noise being generated.

Furthermore, in a folding machine having very high linear processing velocities, the smart nip rollers are required to have low inertia and very high torque in order to accomplish the efficient paper transport and directional change described above. This becomes more challenging as the linear processing velocities increase. As an alternative, after the smart nip rollers are decelerated to zero velocity, another mechanical system (such as a solenoid, cam, etc.) can be used to open the nip between the smart rollers so that no normal force is applied to the media by the smart nip rollers. This allows the media to be pulled from the nip of the smart nip rollers by the feeding/folding rollers (such as rollers 7, 9 of Figure 4). This method allows the media to be decelerated without physical stops and at higher linear velocities and overcomes the low inertia high torque requirements discussed above since the smart nip rollers 23, 25 are not used to transport the media 3 out of the buckle chute 21.

Figure 10 shows one simple mechanical implementation for opening the nip between, for example, smart nip rollers 23 and 25. A solenoid 37 is fixedly mounted to a frame (not shown) of the feeding machine 1 at one end and has a moveable piston rod 38 pivotally mounted to a bracket 39. Bracket 39 is pivotally mounted at one end to the frame of the folding machine 1 and at its other end to the smart nip roller 23. The solenoid 37 is controlled by the microcontroller 13 such that when the smart nip rollers 23, 25 are decelerated to zero velocity, the solenoid 37 is actuated by microcontroller 13 so that the piston rod 38 moves away from the smart nip rollers 23, 25 causing the bracket 39 and smart nip roller 23 to move therewith. This movement opens the nip between the smart nip rollers 23, 25 such that they do not impart a normal force on the media 3. The dashed line in Figure 10 shows the second position of the bracket 39 that results in a vertical movement of smart nip roller 23 away from smart nip roller 25.

It is also important to note that ROM 17 can include a table therein which has all of the accelerating and decelerating parameters for a plurality of particular fold configurations and a plurality of different paper sizes. Thus, when a user selects the type fold and paper size desired through keyboard 41, the microcontroller 13 automatically looks up the corresponding parameters in the table and the smart nip rollers and feeding/folding rollers are controlled in accordance with those parameters to effectuate the selected fold configuration. This eliminates the need for any manual adjustment of the physical components of the folding machine.

Furthermore, while in the preferred embodiment the deceleration of the smart nip rollers 33, 35 as compared to the deceleration of the smart nip rollers 23, 25 was twice as fast, one skilled in the art will recognize that various control schemes can be used to achieve the same result. For example, the deceleration rates could be the same except that at the smart nip rollers 23, 25 there would be a time delay relative to the initiation of the deceleration after detection of the leading edge by the sensor 27 allowing more of the media 3 to pass into buckle chute 21 as compared to buckle chute 31. Furthermore, it is possible to have the feeding/folding rollers 5, 7, 9, and 11 be smart rollers that can decelerate the media 3 within the buckle chutes 21 and 31. In this configuration the adjustable fixed backstops would still be included in the buckle chutes 21, 31 to prevent further movement of the media 3 into the buckle chute, however, since the media 3 can be decelerated to impact the backstops at a reduced velocity, the noises associated with that impact as compared to existing folding machine is greatly reduced.

Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative devices, shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims.