[0001] The present invention relates to a system for controlling replaceable modules, also
known as "customer replaceable units" or CRUs, in a digital printing apparatus, such
as a digital electrophotographic printer/copier.
[0002] In the office equipment industry, different customers have different requirements
as to their business relationship with the manufacturer of the equipment or other
service provider. For various reasons, some customers may wish to own their equipment,
such as copiers and printers, outright, and take full responsibility for maintaining
and servicing the equipment. At the other extreme, some customers may wish to have
a "hands off" approach to their equipment, wherein the equipment is leased, and the
manufacturer or service provider takes the entire responsibility of keeping the equipment
maintained. In such a "hands off" situation, the customer may not even want to know
the details about when the equipment is being serviced, and further it is likely that
the manufacturer or service provider will want to know fairly far in advance when
maintenance is necessary for the equipment, so as to minimize "down time." Other business
relationships between the "owning" and "leasing" extremes may be imagined, such as
a customer owning the equipment but engaging the manufacturer or service provider
to maintain the equipment on a renewable contract basis.
[0003] A common trend in the maintenance of office equipment, particularly copiers and printers,
is to organize the machine on a modular basis, wherein certain distinct subsystems
of a machine are bundled together into modules which can be readily removed from machines
and replaced with new modules of the same type. A modular design facilitates a great
flexibility in the business relationship with the customer. By providing subsystems
in discrete modules, visits from a service representative can be made very short,
since all the representative has to do is remove and replace a defective module. Actual
repair of the module takes place away at the service provider's premises. Further,
some customers may wish to have the ability to buy modules "off the shelf," such as
from an office supply store. Indeed, it is possible that a customer may lease the
machine and wish to buy a succession of modules as needed. Further, the use of modules,
particularly for supply units such as toner bottles, are conducive to recycling activities
which are available, and occasionally mandatory, in many countries.
[0004] In order to facilitate a variety of business arrangements among manufacturers, service
providers, and customers of office equipment such as copiers and printers, it is known
to provide the modules with electronically-readable chips which, when the module is
installed in a machine, enable the machine to both read information from the memory
and also write information, such as a print count, to the module. The present invention
is directed to a generalised system for information exchanges between modules and
machines in an environment of printers and copiers.
[0005] US Patent 4,586,147 discloses an electrophotographic printing apparatus having a
"history information providing device." The device includes a non-volatile memory
for taking out the latest failure information, such as the number of times of paper
jam, and the latest maintenance information such as the total number of pages of printed
paper and storing this information therein. The information thus stored in the non-volatile
memory is accessed by causing the printer to print out the information stored in the
non-volatile memory.
[0006] US Patent 4,961,088 discloses the basic concept of using an electronically-readable
memory permanently associated with a replaceable module which can be installed in
a digital printer. The embodiment disclosed in this patent enables a printer to check
an identification number of the module, to make sure the module is authorised to be
installed in the machine, and also enables a count of prints made with the module
to be retained in the memory associated with the module.
[0007] US Patent 5,491,540 discloses a printer/copier having a plurality of replaceable
parts therein. Each replaceable part has a memory chip associated therewith, and,
with the total apparatus, the various memory chips are connected in serial fashion
by only a single wire.
[0008] EP-A-0 684 526 discloses an equipment control apparatus adapted for controlling communication
between an image formation apparatus and an external apparatus located at a position
apart from said equipment controlling apparatus and said image formation apparatus.
Storage means are used for storing data indicative of a state of the image formation
apparatus and it is possible to communicate with the external apparatus and to transmit
instructions to the external apparatus. The corresponding data comprises a total count
value of image formation apparitions at the time of an abnormality in said image formation
apparatus and the type of that abnormality.
[0009] JP-A-01-063177 discloses the storage of error data in an image forming device with
a non-volatile storage means. The storage controlling means is used for controlling
the storage means to store the error data generated in the imaging forming device.
A printing controlling means prints the data stored in the storage means by the storage
controlling means.
[0010] It is an object of the invention to provide a method for operating a printing apparatus
according to which even after this installation of a corresponding module of the printing
apparatus, it is still possible to see which problems arose during use of this module
and what may be the reason for these problems.
[0011] This object is solved by the features of claim 1.
[0012] According to the invention, malfunction in the apparatus and also of course in the
module or the subsystem disposed therein are detected an a corresponding fault code
is derived which is symbolic of a predetermined type of malfunction. When such a malfunction
occurs, this derived fault code is recorded in an electronically-readable memory.
Not only the fault codes but also the time of said malfunction is record.
[0013] Consequently, it is possible for the manufacturer or the service organization to
read out the fault code and the time of occurrence of the malfunction. This data can
be used when the module is uninstalled and remanufactured.
[0014] The corresponding data may be read after the module is removed from the apparatus
and may also be transmitted to the manufacturer, the service organization or the user
of the apparatus by a distribution board or other control system within the machine.
The data may be transmitted by a corresponding network, as internet, telephone line,
facsimile line, etc.
[0015] According to one embodiment of the invention, it is possible that a malfunction within
the apparatus is a hardware failure wherein such information is quite important to
check if the module is still usable or has to be replaced.
[0016] According to the invention, such a fault code can be recorded in an electronically-readable
memory as part of the module wherein such a memory may be a specially-adapted memory
device called a customer replaceable unit monitor (CRUM). This monitor can be associated
with one or more customer-replaceable modules within the apparatus. Beside the fault
codes, it is possible to store other data in this monitor, as for example service
plan data, market region data, print color value, maximum print volume value, etc.
[0017] Figure 1 is a simplified, partially-elevational, partially-schematic view of an electrophotographic
printing apparatus in which the aspects of the present invention can be embodied.
[0018] Figure 1 is a simplified partially-elevational, partially-schematic view of an electrophotographic
printing apparatus (hereinafter a "machine"), in this case a combination digital copier/printer,
in which many of the aspects of the present invention can be embodied. (As used in
the claims herein, a "printing apparatus" can apply to any machine that outputs prints
in whatever manner, such as a light-lens copier, digital printer, facsimile, or multifunction
device, and can create images electrostatographically, by ink-jet, hot-melt, or by
any other method.) The two main portions of hardware in the machine include a "xerographic
module" indicated as 10, and a "fuser module" indicated as 12. As is familiar in the
art of electrostatographic printing, there is contained within xerographic module
10 many of the essential hardware elements required to create desired images electrophotographically.
The images are created on the surface of a rotating photoreceptor 14 which is mounted
on a set of rollers, as shown. Disposed at various points around the circumference
of photoreceptor 14 are a cleaning device generally indicated as 100, which empties
into a "toner reclaim bottle" 102, a charging corotron 104 or equivalent device, a
developer unit 106, and a transfer corotron 108. Of course, in any particular embodiment
of an electrophotographic printer, there may be variations on this general outline,
such as additional corotrons, or cleaning devices, or, in the case of a color printer,
multiple developer units.
[0019] With particular reference to developer unit 106, as is familiar in the art, the unit
106 generally comprises a housing in which a supply of developer (which typically
contain toner particles plus carrier particles) which can be supplied to an electrostatic
latent image created on the surface of photoreceptor 14 or other charge receptor.
Developer unit 106 may be made integral with or separable from xerographic module
10; and in a color-capable embodiment of the invention, there would be provided multiple
developer units 106, each unit developing the photoreceptor 14 with a different primary-color
toner. A toner bottle 110, which could contain either pure toner or an admixture of
carrier particles, continuously or selectably adds toner or developer into the main
body of developer unit 106. In one particular embodiment of an electrophotographic
printer, there is further supplied a developer receptacle here indicated as 112, which
accepts excess developer directly from the housing of development unit 106. In this
particular embodiment, the developer receptacle 112 should be distinguished from the
toner reclaim bottle 102, which reclaims untransferred toner from cleaning device
100. Thus, in the illustrated embodiment, there are two separate receptacles for used
or excess developer and toner.
[0020] Turning to fuser module 12, there is included in the present embodiment all of the
essential elements of a subsystem for fusing a toner image which has been electrostatically
transferred to a sheet by the xerographic module 10. As such, the fuser module 12
includes a pressure roll 120, a heat roll 122 including, at the core thereof, a heat
element 124, and a web supply 126, which provides a release agent to the outer surface
of heat roll 122 so that paper passing between heat roll 122 and pressure roll 120
does not stick to the heat roll 122. For purposes of the claims herein, either a heat
roll or a pressure roll can be considered a "fuser roll." Also typically included
in a fusing subsystem is a thermistor such as 128 for monitoring the temperature of
a relevant portion of the subsystem.
[0021] Paper or other medium on which images are desired to be printed are retained on one
or more paper stacks. Paper is drawn from the stacks, typically one sheet at a time,
by feed rolls such as indicated as 16a and 16b. When it is desired to print an image
on a sheet, a motor (not shown) activates one of the feed rolls 16a, 16b, depending
on what type of sheet is desired, and the drawn sheet is taken from the stack and
moved through a paper path, shown by the dot-dash line in the Figure, where it eventually
comes into contact with the photoreceptor 14 within xerographic module 10. At the
transfer corotron 108, the sheet receives an unfused image, as is known in the art.
The sheet then passes further along the paper path through a nip formed between pressure
roll 120 and heat roll 124. The fuser subsystem thus causes the toner image to be
permanently fixed to the sheet, as is known in the art.
[0022] In a digital printing apparatus, whether in the form of a digital printer or in a
digital copier, images are created by selectably discharging pixel-sized areas on
the surface of photoreceptor 14, immediately after the surface is generally charged
such as by corotron 104. Typically, this selective discharging is performed by a raster
output scanner (ROS) indicated as 18, which, as is known, includes a modulating laser
which reflects a beam off a rotating reflective polygon. Other apparatus for imagewise
discharging of the photoreceptor 14, such as an LED bar or ionographic head, are also
known. The image data operative of the ROS 18 or other apparatus typically generated
by what is here called an "electronic subsystem" or ESS, here indicated as 20. (For
clarity, the necessary connection between ESS 20 and ROS 18 is not shown.)
[0023] The ESS 20 can receive original image data either from a personal computer, or one
of several personal computers or other apparatus on a network, or, in the case where
the apparatus is being used as a digital copier, via a photosensor bar here indicated
as 22. Briefly, the photosensor bar 22 typically includes a linear array of pixel-sized
photosensors, on which a sequence of small areas on an original hard-copy image are
focused. The photosensors in the array convert the dark and light reflected areas
of the original image into electrical signals, which can be compiled and retained
by ESS 20, ultimately for reproduction through ROS 18.
[0024] If the apparatus is being used in digital copier mode, it is typically desired to
supply an original document handler, here generally indicated as 24, to present either
or both sides of a sequence of hard-copy original pages to the photosensor bar 22.
As is familiarly known, a document handler such as 24 may include any number of rollers,
nudgers, etc. one of which is here indicated as 26.
[0025] There is further provided within an electrophotographic printing/copying apparatus,
what is here called a "distribution board" 30. The distribution board 30 can send
or receive messages, as will be described below, through the same network channels
as ESS 20, or alternately through a telephone or facsimile line (not shown); altemately,
the distribution board 30 can cause messages to be displayed through a display 32,
typically in the form of a touch screen disposed on the exterior of the apparatus.
[0026] Distribution board 30 interacts with specially-adapted memory devices, here called
"customer replaceable unit monitors," or CRUMs, which are associated with one or more
customer-replaceable modules within the apparatus. In the illustrated embodiment,
xerographic module 10 and fuser module 12 are each designed to be customer-replaceable;
i.e., for servicing purposes, the entire module 10 or 12 is simply removed in its
entirety from the apparatus, and can then be immediately replaced by another module
of the same type. As is familiar in the copier or printer industry, consumers can
buy or lease individual modules as needed, and typically replace the modules without
any special training. As illustrated, the xerographic module 10 has associated therewith
a CRUM 11, while the fuser module 12 has associated therewith a CRUM 13. In a particular
embodiment, the xerographic module 10 may further have associated therewith the toner
reclaim bottle 102 and the developer receptacle 112, both of which are separable units.
[0027] The overall purpose, which will be described at length below, of each CRUM 11 and
13 is to retain information for the particular module about how that module is being
used within a machine. Each CRUM 11 or 13 can be considered a small "notepad" on which
certain key data is entered and retained, and also periodically updated. Thus, if
a particular module 10 or 12 is removed from an apparatus, the information will stay
with the module. By reading the data that is retained within a CRUM at a particular
time, certain use characteristics of the CRUM can be discovered.
[0028] The CRUM 11 or 13 is basically in the form of a 2K bit serial EEPROM (electrically
erasable programmable read only memory). Each CRUM 11, 13 is connected to distribution
board 30 using a two-wire serial bus architecture. The non-volatile memory within
the CRUM is designed for special applications requiring data storage in a ROM, PROM,
and EEPROM mode. There is also preferably included in the device a special protection
circuit which can be activated only one time. If this protection circuit is used,
the memory content cannot be accessed regardless of the power supply or bus conditions.
Each CRUM such as 11 or 13 can serve as both a transmitter and receiver in the synchronous
transfer of data with distribution board 30 in accordance with a bus protocol.
[0029] The bus connecting distribution board 30 with one of the CRUMS 11 or 13 comprises
two bidirectional lines, one for data signals and the other for clock signals. According
to a preferred embodiment of the present invention, each data transfer, either data
being sent to the CRUM or recordation therein, or being sent out of the CRUM for reading
thereof, is initiated with a special "start data transfer" condition, which for example
could be defined as a change in the state of the data line from high to low, while
the clock is high. Each data transfer, in either direction, is terminated with a stop
condition, one example of which can be a change in the state of the data line from
low to high while the clock is high. The serial data passing between the distribution
board 30 and a CRUM thus exists between the start condition and the stop condition;
in a preferred embodiment, the number of data bytes between the two conditions is
limited to 8 bytes when updating data within the CRUM, and is not limited when reading
data out of the CRUM. Typically, each byte of 8 bits is followed by one acknowledge
bit. This acknowledge bit is a low level put on the bus by the CRUM, whereas the distribution
board receiving the data will generate an extra acknowledge-related clock pulse. US
Patent 4,961,088, incorporated by reference above, gives a general teaching of the
hardware required for reading a numerical code from a memory associated with a replaceable
module in a digital printing apparatus.
[0030] With respect to the different types of data which can be stored in a CRUM such as
11 or 13 to be read or updated by distribution board 30, the following detailed descriptions
of each type of data can be applied to either CRUM 11 or CRUM 13, although of course
certain types of data will be particularly unique to one type of module, either the
xerographic module 10 or the fuser module 12.
[0031] Service plan: This is a code placed at a location in the one-time programmable memory
of the CRUM. A service plan is given a number associated with the particular arrangement
that exists between the user of the machine and the manufacturer or service organization.
For example, one service plan could specify that the machine is owned by the user,
and the user will buy modules and other parts as they become necessary to replace.
Alternately, another service plan could be a lease arrangement where it becomes the
responsibility of the manufacturer or service organization to replace modules well
in advance of any end-of-life of a module. In terms of data transfers between a CRUM
and the distribution board 30, the identity of the service plan which is loaded by
the manufacturer into the CRUM and read by the distribution board 30 at install of
the module will affect what information is displayed through distribution board 30,
and in what manner. For example, a "lease" arrangement (symbolized by a particular
service plan code in the CRUM) could instruct the distribution board 30 to send a
request to re-order new modules through the network or over a phone line to the manufacturer,
in a manner which is invisible to the user; in contrast, under a "ownership" arrangement
(symbolized by a different service plan code in the CRUM), where it is the responsibility
of the user to obtain new modules, an indication that a module needs to be replaced
will instead be displayed on display 32. Similarly, if some sort of unauthorized module
is placed in the machine, that is a module in which the "service plan" code is not
recognized by the distribution board 30, then distribution board 30 can cause a warning
to be displayed on display 32 that, for example, a warranty is in danger of being
voided.
[0032] Market region: This is another code, placed by the manufacturer in a predetermined
address in the CRUM memory, which identifies the module as belonging to a particular
market region, such as a geographical region. For various reasons it may be desirable
that the geographic regions of the module and the complete apparatus be the same:
for instance, a European machine is designed for 220 volts, while a US machine is
designed for 110 volts, and to place a wrong type of module in a machine could be
catastrophic. Thus, within an initialization procedure, the distribution board 30
reads a code describing a market region stored in the CRUM memory for a confirmation
that the market region of both the modules and the machine match.
[0033] Print count: This is the number of prints which have been created by a particular
module. This number is derived by having the distribution board 30 first read the
current value of this print count from the CRUM memory, and subtract from (or add
to) this number every time the ESS 20 causes a print to be output. Periodically, such
as every five minutes or after every predetermined amount of time in which the machine
is not outputting prints, the value of the print count is updated in the CRUM memory.
[0034] Maximum print volume value: This is a number, entered into a predetermined location
in the CRUM memory at manufacture or remanufacture of the module, which states the
maximum rated number for prints the particular module is designed to output before
replacement. This maximum print volume will of course be compared with the current
print count, and when the print count reaches a certain range relative to the maximum
print volume, the distribution board 30 can (depending on the service plan) display
a particular message on display 32 and/or place a "reorder" notice over the network
or phone line to the manufacturer or supplier, indicating that the module will soon
need replacement.
[0035] The maximum print volume code can further relate to a service plan selected by the
user. For example, if a user prefers a long life of a module over print quality, a
relatively high maximum print volume can be written into the CRUM, even if that means
the later prints may not be of optimal quality; conversely, a user with high quality
requirements may desire a service plan with relatively low maximum print volume so
that optimal print quality can be guaranteed for all prints. Such differences in desired
service plans can be manifest in a service plan code and/or the maximum print volume
code; a particular service plan code in a CRUM such as 11 may even signal the print-quality
algorithms in the machine to be more or less tolerant of less-than-optimal print quality,
depending on user desires.
[0036] Print count security: This is a number, placed in one-time programmable memory within
the CRUM memory, which acts as a "check" to the CRU print count. In a typical embodiment,
after every 15,000 (or other number) prints counted by the print count, the number
in print count security is changed, typically by changing one bit in the print count
security memory from 1 to 0 or vice versa. An important feature of the print count
security value is that, because it is in one-time programmable memory, it cannot be
tampered with by someone trying to artificially extend the useful life of the module.
A fuller description of the principle of using a print count security feature is given
in US patent 5,283,613.
[0037] Pixel usage: This is a number, periodically updated through the distribution board
30, which represents the total cumulative usage of the particular module in terms
of the number of pixels, or only print-black pixels, which have been printed by the
module. The cumulative number of pixels can be used as an important parameter for
judging the overall use of the particular module. A relatively high number of black
pixels, for example, would indicate a relatively high toner coverage of sheets passing
through a particular module, and is a strong indication of how much physical wear
is being experienced by the module. Similarly, the cumulative pixel usage can be compared
with a simultaneous print count in a particular CRUM memory at a particular time,
and a number of pixels (or just black pixels) per individual print can be readily
determined. (The pixel coverage per print can also be normalized taking into account
different sheet sizes.) The raw data by which pixel usage is determined can be derived
either from the image data output by the ESS 20, or more directly could be derived
by simply monitoring the behavior of the ROS 18 over time. For example, the relative
amount of time a laser in ROS 18 is on or off when printing a sheet-sized image can
be readily used as an indication of how much black-area coverage exists on a every
sheet.
[0038] Of course, in a color-capable embodiment of the invention, where there would be a
separate developer unit 106 for each primary color toner, the "black" pixel usage
calculation could be performed and recorded with respect to each color separation
generated by the machine.
[0039] Maximum pixel usage value: This is a number placed in one-time programmable memory
at manufacture or remanufacture of the module, which indicates a maximum rated value
of number of pixels, or black pixels, which could be output by the module. Once again,
as with print count, the pixel usage stored in the CRUM memory is periodically compared
with the maximum pixel usage, and once the pixel usage count reaches a certain range
relative to the maximum pixel usage value, the distribution board 30 can either display
a message on display 32 and/or notify a manufacturer or service representative through
the network or phone line. It is also possible to provide a system which retains the
average daily pixel count, once again by dividing the pixel usage by a number of days,
and this number may also be useful in servicing or remanufacture.
[0040] US Patent 5,636,032 gives a general teaching of pixel-counting techniques useful
for determining a consumption rate of marking material.
[0041] Machine average daily print volume: This is a number stored at a predetermined location
within the CRUM memory, which represents the number of prints that have been made
with the module divided by a certain number of days. The specific technique by which
this number is derived and daily updated by distribution board 30 can be approached
in a number of ways. For example, with every daily update, the distribution board
30 can maintain a ten-day moving average of prints per day. Alternately, if a remote
service organization accessing the distribution board over the network systematically
polls the machine on a periodic basis, such as every three days, the number can be
derived by counting the number of prints since the last remote polling, and this number
can be divided by the number of days since the last polling. This number can be particularly
valuable when the module is being serviced or remanufactured, because it can be an
indication of the overall stress that takes place on a daily basis on the module.
[0042] There are provided at least four status messages at which a machine will display
or otherwise communicate the approach of a need to replace a module. These status
messages are determined by the machine extrapolating the average daily print volume,
and when a particular threshold number of days to module replacement is reached, an
appropriate status message is communicated by the machine, either to the end user
through the display 32 or directly to the service provider over a network. For example,
the machine can communicate a "reorder module" message at some point between 10 and
25 days (the exact day being set by user preference, or as a result of particular
service plan code) before the expected end of life of the module; a "prepare to replace"
message at some point between 2 and 5 days; a "replace today" message at 1-2 days;
and finally a "hard stop" message when the module runs out. The particular service
plan code stored in the CRUM, mentioned above, can signal to the apparatus at what
predetermined threshold number of days (such as between 10 and 25 days) a particular
status message should be communicated (either through the network or through the display)
to the user.
[0043] The service plan code can also include data symbolic of an instruction to communicate
a particular status message over the network (in the case of, for example, a leased
machine), or through display 32 (in the case of for example, a user-owned machine
or a stand-alone copier), or both. Of course, depending on a particular design, certain
types of messages can be displayed and other types of messages can be transmitted
over the network, and how any message is communicated can be determined by the service
plan code.
[0044] Machine speed code: In a product family, a design option is to provide essentially
the same hardware across different-speed products, e.g., the same basic machine, including
the same basic design of replaceable modules, can be sold in either a 40 ppm (page-per-minute)
or 60 ppm version. According to one aspect of the present invention, a code relating
to whether a module such as 10 or 12 is suitable for use at a particular speed (or
both speeds) is retained in the associated CRUM 11 or 13. A machine design option
is to program the machine to operate only at a maximum speed "authorized" by the machine
speed code in the CRUM, so that, for example, if a 40 ppm module is installed in a
machine with a "top speed" of 60 ppm, the machine reading the machine speed code of
40 ppm will be constrained to operate only at 40 ppm, such as by operating stepper
motors in the machine at a special, lower frequency.
[0045] Ancillary part code: In one practical embodiment of the present invention, a xerographic
module such as when shipped to the customer is bundled with a number of feed rolls
such as shown in Figure 1 as 16a or 16b. Although in this particular embodiment feed
rolls are at issue, the general concept here can be applied to any part within the
apparatus which is not part of a module, but which nonetheless should be periodically
replaced by the user. Another possible candidates for occasional replacement would
be, for example, the roller 26 or other part associated with the automatic document
handler 24.
[0046] The overall intention is that an ancillary replaceable part which is not directly
part of the module can still rely on a CRUM within a particular module to remind the
user (through display 32) and/or instruct the manufacturer (by distribution board
30 communicating to the manufacturer or service organization through the network)
that a particular part is due to be replaced. In the case where it is the user's responsibility
to replace the feed roll 16a or 16b, typically the distribution board 30 will have
a protocol in which the user is requested to enter in via the display a confirmation
that he has indeed replaced a particular feed roll. Other possible ancillary parts
include the toner bottle 110, toner reclaim bottle 102 or the used developer receptacle
112, which typically do not have CRUMs directly associated therewith. Depending on
the particular ancillary part that has to be replaced in addition to the module, the
presence of such a feature will be adapted accordingly depending on how often the
particular part must be replaced relative to the rate of replacement of the module
having the CRUM.
[0047] In one currently-preferred embodiment of the invention, a particular code in the
CRUM is used to retain a value related to a number of feed rolls which were shipped
with the whole module. However, more generally, such a code in the CRUM can store
information about an "installation condition" of the ancillary part: for instance
the code can relate to whether the ancillary part was installed substantially simultaneously
with the module, or to the date the ancillary part was installed in the apparatus.
[0048] The high level of detail in machine and module performance afforded by CRUM systems
of the present invention facilitates sophisticated relationships between the customer
and the manufacturer or other service organization. For example, toner bottle 110,
which as mentioned above can contain either pure toner or toner with an admixture
of carrier particles, is typically replaced relatively often by a customer, typically
ten replacements of a toner bottle 110 relative to each replacement of a module 10.
Similarly, the developer receptacle 112 and toner reclaim bottle 102 occasionally
fill and similarly must be emptied and/or replaced by the user. With the features
of the present invention, those parts which are replaced fairly often by a relatively
untrained user can be monitored without the expense of, for example, placing sensors
within the parts, which is a common practice. For example, because the distribution
board 30 is capable of determining values of average print count per day and average
pixel count per day, the system is capable of extrapolating how many days in the future
the toner bottle 110 will run out or toner reclaim bottle 102 or developer receptacle
112 will fill.
[0049] In the case of toner bottle 110, once an amount of toner (or, in the general case,
any marking material such as liquid ink) consumption per day is established, and if
the cumulative daily consumption and original volume of toner in bottle 110 is known,
the machine can predict when the toner bottle 110 will be empty, based on the same
criteria used to determine the expected replacement date of the xerographic module
10: the maximum usable amount of toner in toner bottle 110, the cumulative use of
toner from toner bottle 110, and the calculated rate of toner usage per day. (One
or all of the numbers relating to the amount of toner and the usage thereof can be
retained in CRUM 11, or else in a memory within the machine itself.) This information
facilitates a system where the distribution board 30 can display, a predetermined
number of days in advance, that the toner bottle will need replacement. In the case
where orders for new toner bottles are made directly by distribution board 30 over
a network to the service organization, the machine can be programmed to place the
order for a new toner bottle two or three days in advance of expected run out, so
that a new toner bottle 110 can be mailed to the customer. The same principle will
apply to the emptying and/or replacing of developer receptacle 112.
[0050] In the case of toner reclaim bottle 102, the rate at which the receptacle is filled
will depend not only on the amount of coverage of images created by ROS 18, but also
on the transfer efficiency of the transfer corotron 108: If the transfer efficiency
is relatively low, a relatively large amount of toner will remain on the surface of
photoreceptor 14 even after the transfer step, and this untransferred toner will end
up in toner reclaim bottle 102. Thus, according to one aspect of the present invention,
the expected fill-up point of toner reclaim bottle 102 is determined by an average
number of pixels per day and a measured transfer efficiency of the module 10.
[0051] In order to obtain this value of transfer efficiency, one technique is to have the
module 10 tested at manufacture or remanufacture and a transfer efficiency code relating
to the actual transfer efficiency written into the CRUM 11. In this way, at install,
the distribution board 30 can simply read out the transfer efficiency of the particular
module 10, and use that number in calculations of the expected fill-up time, in days,
of toner reclaim bottle 102.
[0052] Module serial number, module date of manufacture or remanufacture, list of machine
serial numbers: These numbers are either entered into a predetermined location in
the CRUM by the manufacturer, or, in the case of the machine serial number, entered
into the CRUM by the machine itself, via distribution board 30, at install. This information
is always useful when the module is being remanufactured or serviced, and the machine
itself may have a use for knowing the module serial number and date of manufacture.
For example, the distribution board 30 may be programmed to recognize that a module
manufactured before a certain date will lack certain updated features, and can operate
the module accordingly. Maintaining a list of the serial numbers of all machines in
which the module has been installed in its lifetime may be useful in determining whether
a particular machine is acting on a particular module in an undesirable manner. (With
regard to the claims herein, the original manufacture of a module can count as a remanufacture"
for dating purposes.)
[0053] Set point data: The CRUM such as 11 can have loaded at certain predetermined locations
in the memory therein, numbers or other codes which directly relate to specific operating
requirements of various components within xerographic module 10. For instance, the
charge corotron 104, the development unit 106, and transfer corotron 108, along with
any other electrical structure within the module 10, may each need to be biased to
a very specific potential in order for the machine to operate optimally. In a more
sophisticated variation, any or all of the various components to be biased may optimally
be biased according to a specific function which may relate to one or more external
variables such as, for example, temperature, humidity, and current toner level in
the development unit. (In the claims herein, a "xerographic component" shall include
any electric device or electronic component, such as charge corotron 104, development
unit 106, or transfer corotron 108, which operates to change a potential on a charge
receptor such as photoreceptor 14.)
[0054] There can be stored at predetermined locations within the memory of CRUM 11 "set
point codes" (either absolute numbers, or special codes which relate to absolute numbers)
of how much each individual xerographic component within the module 10 should be biased
by the machine (or, some other relevant operating characteristic of the xerographic
component, such as AC frequency). Alternately, the set point codes could indicate
one of a selectable set of functions, such as look-up tables, which represent functions
by which the optimal bias of different components should be calculated.
[0055] Further, the CRUM 11 or 13 could contain or retain information useful in calibrating
on-board sensors such as thermistors or electrostatic voltmeters: the calibration
could be done at manufacture or remanufacture, and the results of the calibration
(i.e., the tested resistance of a thermistor as a function of temperature at certain
test points, or an offset value for a voltmeter) could be loaded into the CRUM just
before delivery of the module to the customer.
[0056] Further, with reference to set points, it may be desirable to provide a system in
which a module 10 of a single basic design can be installed in machines which operate
at different speeds, such as 40 ppm or 60 ppm. It is likely that a particular component
in a module which is installed in a 40 ppm machine will have different voltage, power,
and/or frequency requirements than if the module were installed in a 60 ppm machine.
A similar system can be provided to retain in the CRUM 11 or 13 one set of power and
voltage requirements if the module is installed in a monochrome machine, and another
set of requirements for when the module is installed in a color-capable machine. According
to one variation of the present invention, different sets of set points can be stored
in different predetermined locations in memory, and the machine will access those
addresses in memory depending on whether the machine is rated at one speed or capability
or the other. In this way, a module of a single basic design can be installed and
function successfully in machines rated at different speeds.
[0057] Seam signature: This is a feature unique to the CRUM 11 associated with the xerographic
module 10. In one particular embodiment of the invention, a belt type photoreceptor
such as 14 in Figure 1 has a seam where an image should not be created. It is therefore
desirable that one should know the location of the seam or other "landmark" around
the circumference of photoreceptor belt 14 if the module 10 is removed from a machine.
Such a seam or other landmark is indicated in the Figure as 15. It is useful to remember
the location of the seam 15 for the benefit for a subsequent machine in which the
module 10 is installed, so that the subsequent machine will not accidentally cause
an image to be placed over the seam. There are many possible ways in which the distribution
board 30 can determine the location of the seam 15 in belt 14 at a given time, so
that it may relay this information to the CRUM memory just before the module is removed.
One possible technique is to provide encoder marks (not shown) which can be read by
various photosensitive devices distributed on the circumference of photoreceptor belt
14 in a manner known in the art. Another technique is simply to have the distribution
board maintain a running count of the different types of images that have been printed
with the module 10 since the last time the location of the seam 15 was determined
(e.g., when the module 10 was first installed into the machine, and the seam location
was read).
[0058] Storage of a seam signature code in the CRUM 11 can also be used in a system in which
the CRUM 11 retains data relating to "disabled pitches" along the photoreceptor belt.
For example, US Patent 5,173,733 discloses an electrophotographic printing apparatus
in which latent images can be formed on a plurality of pitches on a rotating photoreceptor
belt. If a defect is detected in one of the pitches, the particular pitch along the
circumference of the photoreceptor belt can be disabled so that the formation of images
on that section is prevented. With the present invention, by using the seam signature
code in the CRUM 11, the location relative to the seam 15 of such a disabled pitch
along the photoreceptor belt can be retained by a disabled-pitch code in the CRUM
as well, so that the disabled pitch can be quickly identified by service personnel
servicing the module, or, alternately, so the pitch will continue to be disabled if
the module 10 is installed in another machine.
[0059] Component failure/ fault code: This is a space within the CRUM memory where fault
codes, each code being associated with a particular type of hardware failure or other
malfunction within the machine, can be recorded, along with the date and time of the
failure, in a predetermined memory location in the CRUM of a particular module. Such
information is noted by the distribution board or other control system within the
machine in a manner familiar in the art. This information is useful when the module
is disinstalled and remanufactured.
[0060] Fuser power and voltage requirements: This is a number, unique to the CRUM 13 in
fuser module 12, which is loaded into the CRUM memory at manufacture where numbers
relating to the voltage and power requirements required to operate the particular
fusing subsystem in module 12. Upon the install of module 12, distribution board 30
reads these requirements from the CRUM 13, and then is capable of sending the desired
voltage and power levels to the fuser subsystem. This feature is important, for example,
because successive generations of fusing subsystems may require different voltage
and power levels, and it is useful to be able to take advantage of lower requirements
afforded by newer module designs.
[0061] An important variation is to provide a system whereby the CRUM 13 provides to the
machine different requirements depending on the rated output speed of the machine,
such as either 60 ppm or 40 ppm. The speed rating of the particular machine may have
an effect on the power requirements to the fusing subsystem, and thus the CRUM 13
will provide different answers to different power requirements depending on the speed
of the machine it is installed in. The CRUM 13 can retain the requirements for one
speed at one address in memory, and the requirements for the other speed at another
address, and the machine will read out of one memory address or the other depending
on its speed. In this way, the same basic fusing module 12 can be installed in machines
of different rated speeds, and the CRUM 13 will "request" particular wattage and voltage
accordingly. The same principle can be applied so that the CRUM 13 can retain different
requirements at different memory locations for either a monochrome or a color-capable
machine.
[0062] Another variation on this principle is to provide at a predetermined memory location
in CRUM 13 numbers representative of temperature requirements or upper or lower temperature
limits, as opposed to electricity requirements, for the fuser subsystem (in such a
case, for instance, if an upper temperature limit is reached, a safety problem can
result and the apparatus may simply shut itself off). If the apparatus includes temperature-sensing
devices, the machine can provide suitable power and voltage to obtain the desired
temperature as sensed by the device. Once again, different speed or type machines
(or the use of different materials as print sheets, such as heavy stock or transparencies)
may require different fuser temperatures, and so the different numbers can be stored
at different memory locations.
[0063] Further with reference to CRUM 13, there may be provided at a predetermined location
in memory a code useful for calibration of a thermistor such as 128. For instance,
a thermistor will have associated therewith an offset voltage which can be interpreted
as a certain absolute temperature, and/or there may be a particular slope of a function
relating output voltage to temperature. The CRUM 13 can retain codes symbolic of the
offset and/or the slope (the slope and offset are referred to in the claims generally
as "calibration parameters"). These codes can be loaded into CRUM 13 at manufacture
or remanufacture based on a direct test of the thermistor in a particular module.
This is also useful in cases where a new design of a thermistor is incorporated in
a new fuser module 12: by loading the offset and slope into CRUM 13, a new design
fuser module can be readily installed in a relatively old machine.
[0064] Web usage: This is a requirement of fusing module 12. This is a number stored in
the CRUM 13 and periodically updated by distribution board 30, reflective of the cumulative
amount of use, either in terms of length or number of prints made, of fuser cleaning
web 126 within the fuser module. Also preferably retained in CRUM 13 is a code symbolic
of a maximum use, either in terms of web length or number of prints, that can be made
with the web 126. Once again, as with other consumables, the usage per unit time of
web 126 can be determined and compared with the maximum use to predict a replacement
time. After a predetermined amount of web 126 has been consumed, the distribution
board 30 can communicate either through display 32 or over the network that the web
126, or the module 12 as a whole, should be replaced within a certain calculated amount
of time.
[0065] The usage of the web 126 can be measured in any manner familiar in the art, such
as by associating a counter with a stepper motor or other mechanism (not shown) which
moves web 126; or, alternately, the usage of web 126 can be inferred from a number
of prints made by the apparatus since the last install of a fuser module 12. The CRUM
13 can also retain at a predetermined location therein a code symbolic of the length
of web 126 provided at install of a particular module 12; in this way, alternate designs
of fuser module 12 (such as a "long-life" web 126 of a particularly long length, or
a low-cost module with a relatively short web 126) can be taken into account. Further,
CRUM 13 can retain at a predetermined location therein a code symbolic of a desired
web speed for web 126, which would be manifest in, for example, the frequency of signals
sent to a stepper motor which moves web 126; in this way, a module 12 having a new
design web 126, which may not require as fast a motion for effective cleaning as a
previous design, can be installed.