Patent Grant
6938894
The invention disclosed herein relates generally to mailing systems, and more particularly to a mailing machine transport mechanism and method.
Mailing systems, such as, for example, a mailing machine, often include different modules that automate the processes of producing mail pieces. The typical mailing machine includes a variety of different modules or sub-systems each of which performs a different task on the mail piece. The mail piece is conveyed downstream utilizing a transport mechanism, such as rollers or a belt, to each of the modules. Such modules could include, for example, a singulating module, i.e., separating a stack of mail pieces such that the mail pieces are conveyed one at a time along the transport path, a moistening/sealing module, i.e., wetting and closing the glued flap of an envelope, a weighing module, and a metering/printing module, i.e., applying evidence of postage to the mail piece. The exact configuration of the mailing machine is, of course, particular to the needs of the user.
Modern mailing machines utilize digital printing techniques for producing images on a mail piece being processed therethrough. Conventional digital printing techniques include bubble jet and ink jet, each of which produces an image in a dot matrix pattern. With digital printing, individual print head elements (such as resistors or piezoelectric elements) are selectively electronically stimulated to expel drops of ink from a reservoir onto a substrate, e.g., a mail piece. In either case, by controlling the timing of energizing of the individual print head elements in conjunction with the relative movement between the print head and the mail piece, a dot matrix pattern is produced in the visual form of the desired indicia, i.e., the evidence of postage.
Digital printing technology has significant advantages when used in a mail handling apparatus as compared to older technology that utilized either a flat platen or a rotary drum to imprint indicia on mail pieces. For example, if the variable indicia image data needs to be changed, it can easily be done through the installation of new or upgraded software versus having to replace the entire meter, since the flat platen and drum are typically not separately removable. Moreover, greater printing speeds can be obtained as compared to conventional mechanical printing systems. However, the use of a digital print head in a mail handling apparatus presents other issues that must be taken into consideration. For example, for the ink jet nozzles of an ink jet printer to properly deposit ink on the surface of the receiving medium, it is critical that a small predetermined gap be maintained between the exit plane of the nozzles and the surface of the receiving medium, typically in the order of one sixteenth to one thirty-second of an inch. This gap is necessary to achieve acceptable image quality, since too small a gap causes scuffing of the print head and to large a gap results in inaccurate dot placement, with either situation resulting in a deteriorated print image. Thus, in the mailing machine environment, it becomes necessary to maintain this critical gap between the exit plane of the ink jet nozzles and the upper surface of the mail pieces being conveyed through the mailing machine.
To accomplish this, the mail pieces, such as, for example, envelopes, postcards, flats, and the like, must be conveyed with the front panels on which the postage indicia is printed lying in a fixed registration plane, which is disposed beneath the exit plane of the nozzles a distance equal to the aforementioned gap. This arrangement is referred to hereinafter as top registration. The problem that arises, however, with top registration is that the plane of the rear panel of the mail piece is not fixed, as is the case with bottom registration, but rather must shift vertically in accordance with variations in the thickness of the mail pieces being conveyed through the mailing machine. Thus, even with top registration, the mailing machine must be capable of accepting mail pieces of varying thickness.
Excessive drag between the belt 18 and the bottom surface of the registration plate 20 is prevented by limiting the amount of movement of the support bracket 12 in the upward direction by a pair of adjustable up-stops 24. The adjustment of the up-stops 24 is critical, as the gap between the belt 18 and the registration plate 20 must be small enough to run card stock yet large enough to prevent the belt 18 from contacting the registration plate 20 when no card stock is present.
Most mailing machines are typically designed to handle mail pieces of different thickness, such as, for example, from card stock up to three-quarters of an inch thick. As such, the transport 10 must be displaceable to accommodate the thicker mail pieces. As a thicker mail piece is transported by the transport 10, the spring 14 will compress (as illustrated in FIG. 2), thereby allowing the mail piece to pass between the belt 18 and the registration plate 20, while still maintaining the registration of the mail piece against the bottom surface of the registration plate 20. Compression of the spring 14 will cause a small gap 40 between the support bracket 12 and the up-stops 24.
There are problems, however, with the conventional top registration transports such as transport 10. First, the transport 10, including the support bracket 12 and drive/idler rollers 16, is relatively large and heavy. Thus, the spring 14 must be strong enough to lift both the transport 10, along with a heavy mail piece, to ensure proper registration of the mail piece along the bottom surface of the registration plate 20. This makes it extremely difficult to provide fine adjustments to the gap. If the belt 18 make contact with the registration plate 20, the amount of friction between the two, caused by the force of spring 14, could damage the motor driving the belt 18 or even prevent the belt 18 from moving at all. It is thus necessary to always maintain the small gap between the belt 18 and registration plate 20 to prevent such damage to the motor or immobilization of the belt 18.
Second, when a thick mail piece exits the transport 10, the spring 14 will decompress until the support bracket 12 contacts the up-stops 24. Generally, this decompression and resulting movement of the support bracket 12 is both quick and forceful, causing a severe shock on the up-stops 24 and transport 10 when the support bracket 12 makes contact. The amount of displacement of the transport 10, and corresponding shock to the up-stops 24 and transport 10 upon return to its original position, increases as the mail piece thickness increases. The sudden decompression of spring 14 causes several problems. First, the noise associated with the support bracket 12 making contact with the up-stops 24 is substantial. Due to the fine adjustment required to maintain the small gap between the belt 18 and registration plate 20, it is not possible to provide any type of damping material to reduce the amount of noise, as any dampening material may deform over time, thereby decreasing the gap and allowing the belt 18 to make contact with the registration plate 20. As noted above, this is not an acceptable situation. In addition, the repeated force with which the transport bracket 12 contacts the up-stops 24 will, over time, affect the gap between the belt 18 and registration plate 20. It is therefore necessary to frequently perform maintenance on the transport 10 to re-adjust the up-stops 24, thereby ensuring that the gap between the belt 18 and the registration plate 20 is small enough to run card stock yet large enough to prevent the belt 18 from contacting the registration plate 20 when no card stock is present. This necessary maintenance increases the cost of owning a mailing machine, as well as increases the down time, i.e., time which the machine cannot be used. If the maintenance is not performed regularly to properly maintain the gap, the transport 10 may become inoperable if the gap has decreased (due to the unacceptable amount of friction between the belt 18 and registration plate 20), or may not properly register thin mail pieces, such as card stock, if the gap has increased. Either of these situations will result in dissatisfaction with the mailing machine.
Thus, there exists a need for a top registration transport that can effectively handle mail pieces of different thickness while alleviating the problems of the conventional transports.
The present invention alleviates the problems associated with the prior art and provides a transport mechanism and method that provides top registration for mail pieces that can effectively handle mail pieces of different thickness. The present invention effectively eliminates the criticality of maintaining the small gap between the belt and registration plate, reduces the occurrence of the spring compressing, and, should the spring compress, reduces the amount of noise and shock associated with the subsequent decompression of the spring.
In accordance with the present invention, a top registration transport mechanism is provided that includes one or more additional rollers that are coupled to the drive/idler rollers for the transport belt by pivotable links. A semi-elastic belt is looped around the drive/idler rollers and additional rollers. The transport mechanism includes a support bracket that is coupled to a spring, which maintains a biasing force on the support bracket in the direction of a registration plate. The amount of movement of the support bracket is limited by one or more up-stops, which preferably are provided with a damping material. The additional rollers have a diameter that is larger than the drive/idler rollers, causing a portion of the transport belt in the area of the additional rollers to be slightly raised. The registration plate above the transport can contact the raised portion of the belt to displace the belt and additional rollers, thereby ensuring that very thin mail pieces, such as, for example, card stock, can be effectively processed by the transport. Because the mass of the displaced components is very small as compared with the mass of the entire transport, the amount of friction between the belt and registration plate, when no mail piece is present, is limited to an acceptable value. As a mail piece traverses the transport, the additional rollers are further displaced, and registration of the mail piece against the bottom of the registration plate is maintained by the force of the belt acting to return the additional rollers to their original position. If a mail piece that is thicker than the difference between the diameter of the additional rollers and drive/idler rollers is processed by the transport, the force will displace the support bracket and compress the spring. When the mail piece exits and the spring decompresses, the damping material that is provided on the up-stops reduces the shock and noise associated with the support bracket contacting the up-stops.
Thus, according to the present invention, the criticality of maintaining the small gap between the belt and registration plate is significantly decreased, as the amount of friction between the belt and registration plate is limited to an acceptable value. Additionally, the compression of the spring supporting the entire transport mechanism will not occur unless the mail piece is a thick mail piece, i.e., the thickness of the mail piece is greater than the difference between the diameter of the additional rollers and the drive/idler rollers. Thus, a large portion of mail pieces can be handled by the transport of the present invention without having to displace the support bracket by compressing the spring. This results in less wear on the transport due to the decrease in shock to the support bracket, up-stops and surrounding components, since the number of times the spring will be compressed and subsequently decompress will be significantly reduced. This also significantly reduces the amount of noise generated by the transport when processing mail pieces. Another advantage is that since the criticality of maintaining the gap between the belt and registration plate is reduced, the up-stops can be provided with a damping material. Accordingly, even when the support bracket is displaced by compression of the spring due to a thick mail piece, when the mail piece exits the transport and the spring decompresses, the resulting noise and shock can be significantly reduced.
Therefore, it should now be apparent that the invention substantially achieves all the above aspects and advantages. Additional aspects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. Moreover, the aspects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The accompanying drawings illustrate a presently preferred embodiment of the invention, and together with the general description given above and the detailed description given below, serve to explain the principles of the invention. As shown throughout the drawings, like reference numerals designate like or corresponding parts.
In describing the present invention, reference is made to the drawings, wherein there is seen in
The base unit 52 further includes a horizontal feed deck 68 which extends substantially from the input end 54 to the output end 56. A plurality of nudger rollers 70 are suitably mounted under the feed deck 68 and project upwardly through openings in the feed deck so that the periphery of the rollers 70 is slightly above the upper surface of the feed deck 68 and can exert a forward feeding force on a succession of mail pieces placed in the input end 54. A vertical wall 72 defines a mail piece stacking location from which the mail pieces are fed by the nudger rollers 70 along the feed deck 68. The mail pieces may be passed through one or more modules, such as, for example, a singulator module (not shown) and moistening/sealing module. Each of these modules is located generally in the area indicated by reference numeral 80. The mail pieces are then passed to a metering/printing module located generally in the area indicated by reference numeral 82.
Referring now to
As previously noted, in conventional top registration transport mechanisms, the gap between the belt and registration plate is critical, as it must be small enough to run card stock yet large enough to prevent excessive friction between the belt and the registration plate. The transport 100 of the present invention effectively eliminates any gap between the belt 118 and registration plate 120 while limiting any frictional drag between the belt 118 and registration plate 120 to a minimal acceptable amount. This is accomplished by the operation of the floating rollers 140, 142 in conjunction with the belt 118. As illustrated in
The operation of transport 100, when transporting mail pieces of different thickness, will now be described with respect to
Referring now to
The transport 100 has several advantages over conventional transports, such as transport 10 illustrated in
Referring now to
The operation of the transport 200 is as follows. Belt 218 operates in substantially the same manner as belt 118 described with respect to
Thus, according to the present invention, a top registration transport system and method that can effectively handle mail pieces of different thickness is provided. The transport mechanism of the present invention effectively eliminates the criticality of maintaining the small gap between the belt and registration plate, reduces the occurrence of the spring compressing, and, should the spring compress, reduces the amount of noise and shock associated with the subsequent decompression of the spring.
Those skilled in the art will also recognize that various modifications can be made without departing from the spirit of the present invention. For example, while the present invention has been described with two additional idler rollers, the invention is not so limited and any number of additional idler rollers could be provided. As another example, for transport mechanisms that utilize multiple belts, more than one belt can be looped around respective additional idler rollers, as long as the combined frictional force of each of the belts that make contact with the registration plate is with an acceptable amount.
While preferred embodiments of the invention have been described and illustrated above, it should be understood that they are exemplary of the invention and are not to be considered as limiting. Additions, deletions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered as limited by the foregoing description but is only limited by the scope of the appended claims.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4821049 | Eckl | Apr 1989 | A |
| 6179419 | Rasmussen et al. | Jan 2001 | B1 |
| 6431778 | Coudray et al. | Aug 2002 | B1 |
| Number | Date | Country | |
|---|---|---|---|
| 20040119223 A1 | Jun 2004 | US |
