Mailing machine including ink jet operation checking for prevention of loss of postal funds

An ink jet printing system includes a user interface for communicating messages between the ink jet printer and an operator and controller in operative communication with the user interface. The controller disables printing of certain information other than a test pattern in response to a predetermined event, generates a random message, prints a test pattern in response to a predetermined event, incorporates the generated random message within the test pattern, receives an indication of the random message from the operator, compares the received random message with the generated random message, and if the received random message equals the generated random message, enables printing of certain information other than the test pattern.

FIELD OF THE INVENTION 
This invention relates to an ink jet printer including a disposable 
cartridge where the ink jet printer includes the capability of ensuring 
that the cartridge is functioning properly before beginning normal 
operations. More particularly, this invention is directed to a mailing 
machine including an ink jet printer having a disposable cartridge wherein 
the mailing machine prompts an operator to perform a test print in 
response to a predetermined event to determine if the cartridge is 
functioning properly so that postal funds are not lost. 
BACKGROUND OF THE INVENTION 
Ink jet printers are well known in the art. Generally, an ink jet printer 
includes an array of nozzles or orifices, a supply of ink, a plurality of 
thin channels connecting the array of nozzles with the ink supply, 
respectively, a plurality of ejection elements (typically either expanding 
vapor bubble elements or piezoelectric transducer elements) corresponding 
to the array of nozzles and suitable driver electronics for controlling 
the ejection elements. Typically, the array of nozzles and the ejection 
elements along with their associated components are referred to as a print 
head. It is the activation of the ejection elements that causes drops of 
ink to be expelled from the nozzles. The ink ejected in this manner forms 
drops which travel along a flight path until they reach a print medium 
such as a sheet of paper, overhead transparency, envelope or the like. 
Once they reach the print medium, the drops dry and collectively form a 
print image. Typically, the ejection elements are selectively activated or 
energized as relative movement is provided between the print head and the 
print medium so that a predetermined or desired print image is achieved. 
Generally, the array of nozzles, supply of ink, plurality of ejection 
elements and driver electronics are packaged into a disposable cartridge. 
In turn, the printer includes a carriage assembly for detachably mounting 
the cartridge thereto. In this manner, a fresh cartridge may be installed 
when the ink supply of the current cartridge has been consumed. Some ink 
jet printers provide an indication to the user that the ink supply is 
running low while others do not. In either case, the printer continues to 
operate with the result being that the user must recognize when the ink 
supply is exhausted and install a fresh cartridge. Thus, it is generally 
intended for the cartridges to be disposable. 
To keep an ink jet printer in proper working order, a variety of 
maintenance actions, such as capping, wiping, normal flushing, power 
flushing, normal purging and power purging, have been developed. Most of 
these maintenance actions are directed toward preventing the array of 
nozzles from becoming clogged with stale ink or other debris. When not in 
use, the print head is sealed off from ambient air by a cap. In this 
manner, the evaporation rate of any solvents or other volatiles contained 
within the ink is reduced and the ink is less prone to clumping. A wiper 
blade is typically employed to squeegee any excess ink or other debris off 
from the face plate of the array of nozzles. This cleaning action is 
typically performed both prior to capping and prior to printing. A normal 
flush involves firing each nozzle in the array of nozzles a predetermined 
number or times to expel ink that may be beginning to clump. A power flush 
is similar to a normal flush except that the number of time each nozzle is 
fired is substantially greater than that for a normal flush. A normal 
purge involves applying a vacuum for a predetermined amount of time to the 
array of nozzles to suck out ink. A power purge is similar to a normal 
purge except that the amount of time that the vacuum is applied is 
substantially greater than that for a normal purge. 
Recently, the postage meter industry and other envelope printing industries 
have begun to incorporate ink jet printers. A typical postage meter (one 
example of a postage printing apparatus) applies evidence of postage, 
commonly referred to as a postal indicia, to an envelope or other 
mailpiece and accounts for the value of the postage dispensed. As is well 
known, postage meters include an ascending register, that stores a running 
total of all postage dispensed by the meter, and a descending register, 
that holds the remaining amount of postage credited to the meter and that 
is reduced by the amount of postage dispensed during a transaction. 
Because U.S. Postal Service regulations require that postage be paid in 
advance, it had traditionally been required that the user of a postage 
meter periodically present the meter to a Postal Service employee for 
recharging. However, more recently it is possible to recharge a meter 
remotely using telephone communications. At the time of recharging, the 
user paid to the Postal Service the amount of postage to be credited to 
the meter and the meter is recharged by increasing the setting of the 
descending register by the amount paid. The postage meter generally also 
includes a control sum register which provides a check upon the descending 
and ascending registers. The control sum register has a running account of 
the total funds being added into the meter. The control sum register must 
always correspond with the summed readings of the ascending and descending 
registers. The control sum register is the total amount of postage ever 
put into the machine and it is alterable only when adding funds to the 
meter. In this manner, the dispensing of postal funds may be accurately 
tracked and recorded. 
Generally, the postage meter may be incorporated into a mailing machine, 
which is also well known in the art, for automated handling of the 
mailpieces. Mailing machines are readily available from manufacturers such 
as Pitney Bowes Inc. of Stamford, Conn., USA and often include a variety 
of different modules, which automate the processes of producing 
mailpieces. The typical mailing machine includes a variety of different 
modules or subsystems where each module performs a different task on a 
mailpiece, such as: singulating (separating the mailpieces one at a time 
from a stack of mailpieces), weighing, sealing (wetting and closing the 
glued flap of an envelope), applying evidence of postage, accounting for 
postage used (performed by the postage meter), feeding roll tape or cut 
tape strips for printing and stacking finished mailpieces. However, the 
exact configuration of each mailing machine is particular to the needs of 
the user. Customarily, the mailing machine also includes a transport 
apparatus, which feeds the mailpieces in a path of travel through the 
successive modules of the mailing machine. 
Due to the inherent nature of printing an indicia of value (a postal 
indicia being the equivalent of money), several issues arise with 
utilizing ink jet printing in a postage printing device. For example, if a 
general purpose ink jet printer runs out of ink or malfunctions while 
printing a document, then the user merely installs a new cartridge and 
reprints the document. On the other hand, if a postage printing device 
runs out of ink or malfunctions while printing a postal indicia, then the 
user loses money because the postal funds associated with that postal 
indicia cannot be recovered. Therefore, it is desirable to ensure the 
proper functioning of the cartridge. 
In some ink jet printers, it is known to print a test pattern after 
installing a fresh cartridge. Generally, the test pattern may serve as an 
indicator of the performance of the ink jet printer or may be used to 
register multiple print heads. However, the operator of the ink jet 
printer may disregard the test pattern by not printing it or by ignoring 
the results. If the operator bypasses or ignores the test print, then 
there is no assurance that the ink jet printer is functioning properly 
before normal operations resume. 
Therefore, there is a need for a postage printing apparatus that prevents 
an operator from bypassing or ignoring a test pattern printed in response 
to a predetermined event, such as the installation of a fresh cartridge. 
SUMMARY OF THE INVENTION 
The present invention provides a closed loop check routine for ensuring the 
ink jet printer is in proper working order before certain information may 
be printed. 
In conventional fashion, this invention may be incorporated into a variety 
of devices employing ink jet printing, such as: a general purpose ink or a 
postage printing system (mailing machine, postage meter, or the like) 
In accordance with the present invention, there is provided an ink jet 
printing system comprising a user interface for communicating messages 
between the ink jet printer and an operator and controller in operative 
communication with the user interface. The controller disables printing of 
certain information other than a test pattern in response to a 
predetermined event, generates a random message, prints a test pattern in 
response to a predetermined event, incorporates the generated random 
message within the test pattern, receives an indication of the random 
message from the operator, compares the received random message with the 
generated random message, and if the received random message equals the 
generated random message, enables printing of certain information other 
than the test pattern. 
Thus, the test pattern must be of sufficient quality and of sufficient 
unpredictable content. In this manner, the operator must and is able to 
discern the random message. Unless the random message is accurately read 
and entered, the ink jet printing system will not resume normal 
operations. 
A method of operating an ink jet printing system is also provided. 
Therefore, it is now apparent that the present invention substantially 
overcomes the disadvantages associated with the prior art. Additional 
advantages of the invention will be set forth in the description which 
follows, and in part will be obvious from the description, or may be 
learned by practice of the invention. The objects and advantages of the 
invention may be realized and obtained by means of the instrumentalities 
and combinations particularly pointed out in the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 1, a mailing machine 10 including a feed deck 240 and a 
user interface 380 is shown. The user interface 380 includes a numeric 
keypad 382, a set of keys 383, a display 384 (CRT, LED, LCD, or otherwise) 
and a set of function keys 385. The keys 383 provide access to a set of 
"soft" commands or functions, such as: enter, clear, download postage, 
generate report, account setup, diagnostics and the like. By soft 
commands, it is meant that these commands are not directly related to 
processing a batch of mailpieces. In contrast, the function keys 385 
provide access to a set of "hard" commands, such as: start, stop, print 
tape, reset batch counter, weigh mode on/off, sealer/moistener mode on/off 
and the like, which are directly related to processing a batch of 
mailpieces. Further details of the mailing machine 10 will be provided in 
the remaining Figures and the written text below. 
Referring to FIG. 2, an simplified schematic of an elevational view of the 
mailing machine 10 is shown. The mailing machine 10 includes a printer 
module 100, a conveyor apparatus 200, a micro control system 300 and a 
singulator module 400. Other modules of the mailing machine 10, such as 
those described above, have not been shown for the sake of clarity. The 
singulator module 400 receives a stack of envelopes (not shown), or other 
mailpieces such as postcards, folders and the like, and separates and 
feeds them in a seriatim fashion (one at a time) in a path of travel as 
indicated by arrow A. Downstream from the path of travel, the conveyor 
apparatus 200 feeds the envelopes 20 in the path of travel along the deck 
240 past the printer module 100 so that a postal indicia can be printed on 
each envelope 20. Together, the singulator module 400 and the conveyor 
module 200 make up a transport apparatus for feeding the envelopes 20 
through the various modules of the mailing machine 10. 
The singulator module 400 includes a feeder assembly 410 and a retard 
assembly 430 which work cooperatively to separate a batch of envelopes 
(not shown) and feed them one at a time to a pair of take-away rollers 
450. The feeder assembly 410 includes a pair of pulleys 412 having an 
endless belt 414 extending therebetween. The feeder assembly 410 is 
operatively connected to a motor 470 by any suitable drive train which 
causes the endless belt 414 to rotate clockwise so as to feed the 
envelopes in the direction indicated by arrow A. The retard assembly 430 
includes a pair of pulleys 432 having an endless belt 434 extending 
therebetween. The retard assembly 430 is operatively connected to any 
suitable drive means (not shown) which causes the endless belt 434 to 
rotate clockwise so as to prevent the upper envelopes in the batch of 
envelopes from reaching the take-away rollers 450. In this manner, only 
the bottom envelope in the stack of envelopes advances to the take-away 
rollers 450. Those skilled in the art will recognize that the retard 
assembly 430 may be operatively coupled to the same motor as the feeder 
assembly 410. 
The take-away rollers 450 are located adjacent to and downstream in the 
path of travel from the singulator module 400. The take-away rollers 450 
are operatively connected to motor 470 by any suitable drive train (not 
shown). Generally, it is preferable to design the feeder assembly drive 
train and the take-away roller drive train so that the take-away rollers 
450 operate at a higher speed than the feeder assembly 410. Additionally, 
it is also preferable that the take-away rollers 450 have a very positive 
nip so that they dominate control over the envelope 20. Consistent with 
this approach, the nip between the feeder assembly 410 and the retard 
assembly 430 is suitably designed to allow some degree of slippage. 
The mailing machine 10 further includes a sensor module 500 which is 
substantially in alignment with the nip of take-away rollers 450 for 
detecting the presence of the envelope 20. Preferably, the sensor module 
500 is of any conventional optical type which includes a light emitter 502 
and a light detector 504. Generally, the light emitter 502 and the light 
detector 504 are located in opposed relationship on opposite sides of the 
path of travel so that the envelope 20 passes therebetween. By measuring 
the amount of light that the light detector 504 receives, the presence or 
absence of the envelope 20 can be determined. Generally, by detecting the 
lead and trail edges of the envelope 20, the sensor module 500 provides 
signals to the micro control system 300 which are used to determine the 
length of the envelope 20 and measure the gap between successive envelopes 
20. 
The conveyor apparatus 200 includes an endless belt 210 looped around a 
drive pulley 220 and an encoder pulley 222 which is located downstream in 
the path of travel from the drive pulley 220 and proximate to the printer 
module 100. The drive pulley 220 and the encoder pulley 222 are 
substantially identical and are fixably mounted to respective shafts (not 
shown) which are in turn rotatively mounted to any suitable structure (not 
shown) such as a frame. The drive pulley 220 is operatively connected to a 
motor 260 by any conventional means such as intermeshing gears (not shown) 
or a timing belt (not shown) so that when the motor 260 rotates in 
response to signals from the micro control system 300, the drive pulley 
220 also rotates which in turn causes the endless belt 210 to rotate and 
advance the envelope 20 along the path of travel. 
The conveyor apparatus 200 further includes a plurality of idler pulleys 
232, a plurality of normal force rollers 234 and a tensioner pulley 230. 
The tensioner pulley 230 is initially spring biased and then locked in 
place by any conventional manner such as a set screw and bracket (not 
shown). This allows for constant and uniform tension on the endless belt 
210. In this manner, the endless belt 210 will not slip on the drive 
pulley 220 when the motor 260 is energized and caused to rotate. The idler 
pulleys 232 are rotatively mounted to any suitable structure (not shown) 
along the path of travel between the drive pulley 220 and the encoder 
pulley 222. The normal force rollers 234 are located in opposed 
relationship and biased toward the idler pulleys 232, the drive pulley 220 
and the encoder pulley 222, respectively. 
As described above, the normal force rollers 234 work to bias the envelope 
20 up against the deck 240. This is commonly referred to as top surface 
registration which is beneficial for ink jet printing. Any variation in 
thickness of the envelope 20 is taken up by the deflection of the normal 
force rollers 234. Thus, a constant space (the distance between the 
printer module 100 and the deck 240) is set between the envelope 20 and 
the printer module 100 no matter what the thickness of the envelope 20. 
The constant space is optimally set to a desired value to achieve quality 
printing. It is important to note that the deck 240 contains suitable 
openings (not shown) for the conveyor apparatus 200. 
The sensor module 500, the singulator module 400, conveyor apparatus 200 
and the printer module 100 are under the control of the micro control 
system 300 which may be of any suitable combination of microprocessors, 
firmware and software. The micro control system 300 includes a motor 
controller 310 which is in operative communication with the motors 260 and 
470, a printer controller 320 which is in operative communication with the 
printer module 100, a sensor controller 330 which is in operative 
communication with the sensor module 500; an accounting module 340 for 
authorizing and accounting for the dispensing of postal funds; a 
microprocessor 360; a security application specific integrated circuit 
(ASIC) 370 and the user interface 380. The motor controller 310, the 
printer controller 320, the sensor controller 330, the accounting module 
340 and other various components of the micro control system 300 are all 
in operative communication with each other over suitable communication 
lines. Generally, the microprocessor 360 coordinates the operation and 
communications between the various sub-systems of the mailing machine 10. 
Referring to FIG. 3, the printer module 100 is used for printing a postal 
indicia (not shown) on the envelope 20 (not shown). The printer module 100 
includes a carriage 120 and a cartridge 110 detachably mounted to the 
carriage 120 in conventional fashion using any suitable structure (not 
shown). The cartridge 110 includes a nozzle plate 111 including an array 
of nozzles (not shown), an actuator plate 112 including a plurality of 
ejection elements (not shown) corresponding to the array of nozzles and an 
ink supply 114 in is flowing communication with the actuator plate 112 and 
the nozzle plate 111. Additionally, the cartridge 110 includes a contact 
pad 113 detachably mounted to a corresponding contact pad 121 located on 
an exterior surface of the cartridge 110. The contact pad 113 is in 
operative communication with the actuator plate 112 via a flex strip 115. 
The contact pad 121 is in operative communication with the printer 
controller 320 so that the printer controller 320 may supply suitable 
drive signals to the actuator plate 112 of the cartridge 110. 
The printer module 100 further includes a maintenance assembly (not shown) 
for capping and wiping the nozzle plate 111 and a repositioning assembly 
(not shown) for moving the carriage 120 and thus the cartridge 110 from a 
maintenance position to a print position. In the print position, the 
cartridge 110 is disposed above the path of travel of the envelope 20 (not 
shown) so that printing may occur. 
Each cartridge 110 is initially filled with a predetermined amount of the 
ink 114. Since the ink 114 is used during printing and maintenance 
operations, the ink 114 will be gradually consumed over time and 
eventually a fresh cartridge 110 will need to be installed. To keep track 
of the amount of the ink 114 available, the printer controller 320 
estimates an amount of the ink 114 used during all operations and 
subtracts this amount from the predetermined amount initially available to 
obtain an estimate of an amount of the ink 114 remaining. Any conventional 
technique for estimating ink can be used, such as counting individual ink 
drops or counting postal indicias and maintenance operations (each 
consuming an estimated amount of the ink 114), may be employed. In the 
alternative, an active system (not shown), such as a providing a 
thermistor in the ink reservoir, can be employed for actively measuring 
the amount of remaining ink. 
Referring to FIG. 4 in view of FIGS. 2 and 3, a test pattern 390 printed on 
the envelope 20 by the print module 100 is shown. The test pattern 390 
spans the length of the array of nozzles (not shown), as identified by 
dashed lines L.sub.top and L.sub.bottom, so that each nozzle must be 
utilized to complete the test pattern 390. 
With the structure of the mailing machine 10 described as above, the 
operational characteristics will now be described. Referring primarily to 
FIG. 5, while referencing the structure of FIGS. 1, 2, 3 and 4, a flow 
chart of a check routine 600 indicating the operation of the mailing 
machine 10 in accordance with the present invention is shown. The check 
routine 600 represents a closed loop process for ensuring that the printer 
module 100 (more particularly the cartridge 110) is functioning properly 
before normal operations resume. Generally, the activities contained 
within the check routine 600 are coordinated by the micro control system 
300 and more specifically at the supervision of the microprocessor 360. 
At 602, when the print controller 320 determines that the amount of ink 114 
remaining is less than or equal to threshold value, the micro control 
system 300 recognizes an out of ink condition. Next, at 604, the 
microprocessor 360 suspends operation of the accounting module 340 so that 
no postal funds may be dispensed and no postal indicia may be printed. In 
the alternative, the micro control system 300 may take any other action 
that has the effect of inhibiting printing of postage. However, the micro 
control system 300 may allow printing of other information, such as: 
reports & diagnostic results. Next, at 606, the operator is instructed via 
a message on the user interface 380 to install a fresh cartridge 110. 
Next, at 608, the operator is instructed via a message on the user 
interface 380 to feed a test envelope 20 through the mailing machine 10. 
Next, at 610, the microprocessor 360 generates a random number. Next, at 
612, the random number is printed on the envelope 20 as the test pattern 
390. Next, at 614, the operator is instructed to retrieve the envelope 20 
having the test pattern 390 and to enter the random number into the 
mailing machine 10 using the keypad 382. 
After the random number has been entered by the operator, a determination 
is made, at 616, whether or not the entered random number is the same as 
the generated random number. If yes, then at 618 normal operations resume. 
That is, operation of the accounting module 340 is established so that 
postal funds may be dispensed. On the other hand, if the answer is no, 
then at 620 the operator is instructed to check the cartridge 110 before 
control returns to 608. 
It should now be apparent that the check routine 600 provides a safeguard 
against the unintentional loss of postal funds due to a malfunctioning 
print module 100. Basically, any problem that produces a poor quality test 
pattern 390 where the random number cannot be read legibly forces the 
operator to make any necessary corrections before continuing. Examples of 
the types of problems that the check routine 600 will help to address are: 
(i) failure of the operator to remove the protective cover over the nozzle 
plate 111 of a new cartridge 110; (ii) installation of a defective 
cartridge 110; (iii) failure of the operator to install the cartridge 110 
properly in the carriage 120 so that the contact pads 113 and 121 are in 
proper mating relationship; (iv) installation of an empty or near empty 
cartridge 110; (v) clogged or malfunctioning nozzles within the cartridge 
110; and (vi) failure of the operator to interrogate the test pattern 390 
before starting a batch run. 
In the preferred embodiment, the failure of the comparison between the 
generated random number and the entered random number sets a flag in 
permanent memory that disables postage accounting and postage printing. 
This way, the operator cannot by-pass this routine 600 by power cycling 
the mailing machine 10. Thus, the comparison operation must be executed 
successfully. 
In the preferred embodiment, the check routine 600 is performed upon 
replacement of the cartridge 110 in response to an out of ink condition. 
However, the check routine 600 with only slight modification may be run in 
response to other predetermined events, such as: system power up/reboot; 
before each batch run; after a predetermined number of cycles; and/or at 
the request of the operator. Those skilled in the art will recognize that 
there exists great flexibility on when the check routine 600 is run and 
what portions of the check routine 600 need to be run. 
In the preferred embodiment, the test pattern 390 is a random number 
generated by a suitable random number generator or obtained from a table 
of numbers (not shown) previously stored within the micro control system 
300 by the mailing machine manufacturer. However, so long as the random 
number used within the test pattern 390 is not readily discernable by the 
operator and consecutive numbers are not the same, the random numbers may 
be is obtained in any suitable manner. For example, the random number may 
be derived from register data and/or clock/calendar data. 
As an extension of the basic concepts of the present invention, at 620, the 
operator may be prompted with a list of suggested corrective actions 
corresponding to those examples of the types of problems discussed above. 
In this manner, troubleshooting may be expedited. As a further extension, 
the operator may be prompted to perform a maintenance operation, such as a 
power purge, on the cartridge 110 before initiating the next test so that 
any clogged nozzles may be restored to proper working order. 
As another extension of the basic concepts of the present invention, if the 
comparison between the entered random number and the generated random 
number fails a predetermined number of times before being successful, then 
the operator may be prompted to call customer technical support and the 
telephone number along with a diagnostic code may be displayed. 
Many features of the preferred embodiment represent design choices selected 
to best exploit the inventive concept as implemented in a mailing machine. 
However, those skilled in the art will recognize that various 
modifications can be made without departing from the spirit of the present 
invention. For example, the preferred embodiments are described with 
respect to bubble jet technology where the print head and the ink supply 
are integrated within the cartridge 110. However, those skilled in the art 
will readily be able to adapt the inventive concepts of the present 
invention to other cartridge and print head configurations. 
As another example, the preferred embodiments are described with respect to 
using a random number as the text pattern 390. This is because the typical 
mailing machine possess a full numeric keypad 382, but not a full alpha 
keypad. However, those skilled in the art will be able to adapt the 
inventive concepts of the present invention to utilize any suitable random 
message and data entry scheme. For instance, the test pattern 390 may be 
an alpha-numeric expression with other symbols included and the operator 
may be asked to choose the correct one from those presented on the display 
384. 
Therefore, the inventive concept in its broader aspects is not limited to 
the specific details of the preferred embodiments but is defined by the 
appended claims and their equivalents.