Printing – Selective or progressive – Rotary machines
Reexamination Certificate
1995-03-07
2001-01-23
Yan, Ren (Department: 2854)
Printing
Selective or progressive
Rotary machines
Reexamination Certificate
active
06176178
ABSTRACT:
The invention relates generally to postage meters, also called franking machines, and relates more particularly to an improved mechanism for setting the value wheels which determine the amount of postage that is printed on a mail piece.
Postage meters are an important part of the postal system. In the United States, for example, about half of all the postage value applied to mail pieces is applied by postage meters rather than by the purchase and application of postage stamps.
Before a model of postage meter is entered into service, it must be tested and certified by the postal authorities. The certification process is directed in part to the ability of the meter to withstand efforts by dishonest parties to print postage without paying for it. Manufacturers of postage meters thus design each model of postage meter to resist such efforts. The meter is, for example, housed in a secure housing.
The majority of postage meter models employ a rotating print head, or rotor, to print postage on mail pieces. The print head contains value wheels, each of which prints one digit of the postage value. Each value wheel is set, prior to the printing of postage, by movement of a mechanical linkage. The linkage must be designed to satisfy many conditions. For example, the linkage must be mechanically reliable, it must set each of (typically five) print wheels to any of ten digit positions, it cannot cost too much money, and perhaps the most daunting condition is that it has to work even though the rotor, and its print wheels, rotate relative to the rest of the postage meter. A typical postal certification test will require that the meter work well during a million print cycles (rotations of the print rotor) and half a million settings (adjustments of the print wheel positions).
The postage meter art is filled with attempts to accomplish the above-mentioned design requirements simultaneously with protecting the meter against misuse by dishonest persons. An extreme example of the latter may be seen in U.S. Pat. No. 4,271,481 to Check et al., in which each print wheel has an integrally mounted transducer that generates a four-wire binary electrical signal communicating the absolute position of the wheel. Five such print wheel/transducer assemblies would not fit within a typical print rotor, of course, and would not be able to be positioned to print five adjacent digits. And it would, of course, be impractical in the extreme to attempt to bring twenty discrete wires out of the rotating rotor to the main body of the postage meter.
The balancing of the numerous requirements on the postage meter most frequently leads to a design in which the rotor itself is purely mechanical. An electromechanical system in main body of the postage meter actuates mechanical linkages to the rotor, and thereby sets the print wheels. The system is under microprocessor control, and feedback sensors permit the microprocessor to achieve a very high degree of confidence that during setting, the electromechanical system of the main body of the meter has moved its linkages to the desired positions. As a consequence, assuming the mechanical linkages to the print wheels are intact, the designer of the meter can have a high degree of confidence that the value wheels are likewise in the desired positions. Stated differently, the confidence that no dishonest person would be able to get postage without paying for it is achieved largely through the use of sophisticated sensors, but for the last few inches of wheel setting mechanism the confidence is achieved by physical robustness thereof.
FIG. 1
shows a typical postage meter
40
. A mail piece
41
passes through a slot
42
and receives an imprint of postage from the rotor, not visible in FIG.
1
. The rotor is not visible because it is surrounded by a housing or case
43
with a cover
44
. Housing
43
is a secure housing as required by postal authorities.
FIG. 2
shows in endwise view a typical print rotor
50
of the postage meter. Disposed around the periphery of the rotor
50
are features which, when brought into contact with the mail piece, print the various parts of the postage indicium. A typical postage indicium, described from right to left as seen on a mail piece, includes a box containing a postage amount, a circle containing the date, and optionally an indication of the mail class and an advertisement. The features of the indicium thus correspond respectively to the part of the rotor containing the value print wheels
30
, the date print wheels
51
, the mail class print die
52
, and the advertising plate
53
. Turning again to
FIG. 1
, it will be appreciated that cover
44
is required to permit user access to date wheels
51
(if manually set), to the mail class die
52
, and to the advertising plate
53
.
FIG. 3
shows in perspective view rotor
50
. In this view it is possible to see part of value wheels
30
. Rotor
50
has a long axle or shaft
55
which is held within the main body of the meter when in use. In this view it is also possible to see portions of racks
32
, about which more will be said later.
FIG. 4
shows in simplified form a prior-art wheel-setting mechanism for a postage meter. One value wheel
30
, also called a print wheel, is shown while the others are omitted for clarity. The print wheel has ten faces
45
, one shaped to print each Arabic digit. The wheel
30
turns on an axle
39
, and the wheel
30
is stacked with the other print wheels of the rotor. Formed with the wheel is a gear portion
31
having a number of teeth that is a multiple of ten; in the wheel shown the number of teeth is ten. In the figure the topmost face of the wheel is the face that extends slightly from the periphery of the rotor and that will come in contact with a mail piece upon rotation of the rotor.
The mechanism also has racks
32
, one for each print wheel, only one of which is shown in FIG.
4
. The rack
32
has gear teeth
33
that engage with the gear teeth of gear
31
. Rack
32
has a long portion
34
which rests within a channel of the axle
55
(FIG.
3
). Shown in simplified form is mechanism
35
which engages the long portion
34
, moving it axially as needed to effect changes in the position of the value wheel
30
. The mechanism
35
includes motor
36
coupled to gear
37
which engages with rack
32
. It will be appreciated that when rotor
50
rotates so as to imprint postage on a mail piece, rack
32
moves out of engagement with gear
37
(e.g. it moves out of its home position) and is locked by engagement with a locking member omitted for clarity in FIG.
4
. When the rotation of the rotor
50
has finished, the rack
32
is once again in engagement with the gear
37
, that is to say it is in its home position again. Under normal conditions the rotor
50
is motionless only in its home position; whenever it is not in its home position it is in motion. Generally speaking the only circumstance in which the rotor
50
would be motionless in a position other than the home position is if electric power to the meter
40
is lost during a franking operation, that is, if electric power is lost during the process of printing postage. The design of the meter is such that when power is reapplied the meter will continue its franking cycle until the rotor is once again at its home position.
The mechanical configuration of wheel
30
and rack
32
is shown in greater detail in FIG.
5
. Rack
32
runs on guide rod
38
, which is fixed to the structure of the rotor
50
. Guide rod
38
confines the movement of rack
32
so that it cannot move laterally (that is, in the axial direction of the axle
39
of the value wheel
30
) nor can it move vertically (that is, it cannot move closer to the wheel
30
nor downward closer to the axis of the rotor
50
). The rack
32
can only move left and right in the figure, which movement is parallel to the axis of the rotor
50
.
It will be appreciated that while
FIG. 5
shows only one print wheel
30
, a typical postage meter has four or more print wheels
30
located on the axle
39
. Each print wheel
30
has a
Etter Stefan
Gillieron Christian
Moy Christian
Nietlispach Thomas
Schor Stephan
Ascom Hasler Mailing Systems AG
McLaughlin James F.
Perman & Green LLP
Yan Ren
LandOfFree
Tamper-resistant postage meter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Tamper-resistant postage meter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tamper-resistant postage meter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2528219