EP0012821A2
Expired / Lapsed
EP
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Ink jet printer with means for monitoring its ink jet head-operation
Assignee: International Business Machines Corp
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Filing: 1979-11-08
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Granted: —
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Expires: 1999-11-08
Abstract
Abstract A system and method are disclosed for analyzing operation of the ink jet head of an ink jet printer. Initiation of start-up is sensed, as is the pressure build-up in the ink jet head as ink is supplied thereto. The time lapse between initiation of start-up and the commencement of pressure build-up is determined, as is the time required forthe pressure within the ink jet head to build to an operational level, and outputs indicative thereof are utilized for determination of fault occurrence and indication of faults or initiation of fault correction in response thereto. The system includes a pair of counters 33, 35. Counter 33 is controlled by a start-up initiation signal via gate 29 and the output of a comparator 39 which receive a predetermined reference signal 1 and a signal indicative of pressure build-up at the ink jet head. Counter33 thus reaches a count indicative of the time taken for the ink pressure to reach the first reference pressure. Counter35 similarly provides a count indicative of the time taken for the ink pressure to change from the first to the second reference pressure. The outputs of counters 33, 35 or gated to microprocessor 25 where they are analyzed to determine whether the printer is operating correctly or whether maintainance or repair is required.
Inventors
- 👤 Eugene Thomas Kennedy
- 👤 Donald Lee Janeway
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 02:18
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/17; B41J2/1707
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
55 words
A method for analyzing operation of an ink jet head, said method comprising: sensing the pressure characteristic in an ink jet head during a predetermined pressure change period; and detecting from said sensed pressure characteristic any faults in performance of said ink jet printer causing said pressure characteristic to depart from a predetermined desired characteristic.
Claim 2
Independent Claim
55 words
A method for analyzing operation of an ink jet head, said method comprising: sensing the pressure characteristic in an ink jet head during a predetermined pressure change period; and detecting from said sensed pressure characteristic any faults in performance of said ink jet printer causing said pressure characteristic to depart from a predetermined desired characteristic.
Claim 3
Dependent Claim
69 words
An ink jet printer characterised by the provision therein of a system for analyzing operation of the printer, said system comprising sensing means for sensing the actual. pressure characteristic of ink in the ink jet head during a period of pressure change; and detecting means for detecting from said actual pressure characteristic departure from at least portions of a predetermined pressure characteristic corresponding to predetermined operation of the printer.
Claim 4
Dependent Claim
69 words
An ink jet printer characterised by the provision therein of a system for analyzing operation of the printer, said system comprising sensing means for sensing the actual. pressure characteristic of ink in the ink jet head during a period of pressure change; and detecting means for detecting from said actual pressure characteristic departure from at least portions of a predetermined pressure characteristic corresponding to predetermined operation of the printer.
Claim 5
Dependent Claim
37 words
A printer as claimed in claim 2, further characterised in that said sensing means includes a pressure responsive transducer at said ink jet head for sensing the pressure thereat and providing an electrical output signal proportional thereto.
Claim 6
Dependent Claim
19 words
A printer as claimed in claim 3, further characterised in that said pressure responsive transducer is a piezoelectric crystal.
Claim 7
Dependent Claim
44 words
A printer as claimed in claim 2, 3 or 4, further characterised in that said detecting means includes time determining means for determining the amount of time necessary for pressure in said ink jet head to build to a predetermined pressure level during start-up.
Claim 8
Dependent Claim
48 words
A printer as claimed in claim 5, further characterised in that said time determining means includes a counter ° actuated at the initiation of start-up and a comparator for stopping the count on said counter when said pressure in said ink jet head reaches said predetermined pressure level.
Claim 9
Dependent Claim
47 words
A printer as claimed in claim 6, further characterised in that said counter is connected with a gate receiving a clock input and an indication of initiation start-up whereby said counter counts at the frequency of said clock when said clock is actuated at initiation of start-up.
Claim 10
Dependent Claim
48 words
A printer as claimed in claim 2, 3, 4 or 5, further characterised in that said time determining means includes i means for determining the amount of time necessary for pressure in said ink jet head to build to at least two different predetermined pressure levels during start-up.
Claim 11
Dependent Claim
124 words
A printer as claimed in claim 8, further characterised in that said time determining means includes first and second counters and first and second comparators connected with said sensing means, with said first counter being actuated to start counting at the initiation of start-up and connected to said first comparator to stop counting when the pressure in said ink jet head reaches a first of said predetermined different pressure levels, and with said second counter being connected with said first comparator to start counting when said pressure in said ink jet head reaches said first predetermined pressure level and connected with said second comparator to stop counting when said pressure in said ink jet head reaches the second of said predetermined different pressure levels.
Claim 12
Dependent Claim
73 words
A printer as claimed in claim 9, further characterised in that said first and second counters are connected with said first and second gates, respectively, both of which receive a clock input and with said first and second gates also receiving an indication of initiation of start-up and the output from the first comparator, respectively, whereby each counter is caused to count at the frequency of said clock until said count is terminated.
Claim 13
Dependent Claim
39 words
A printer as claimed in any one of claims 1 to 10, further characterised in that said system includes means for initiating a recovery procedure based on a fault corresponding to a characteristic departure detected by said detecting means.
Claim 14
Dependent Claim
36 words
A printer as claimed in claim 11, further characterised in that said means for initiating said recovery procedure includes a microcomputer comprising memory means for receiving indications of faults from said detecting means and a microprocessor.
Claim 15
Dependent Claim
45 words
A printer as claimed in claim 12, further characterised iii"that said system includes indicating means for indicating a need for valve maintainence, and in that microprocessor controls activation of said indicating means in response to an output from said memory means indicative of valve fault.
Claim 16
Dependent Claim
43 words
A printer as claimed in claim 13, further characterised in that said system includes storing means for storing valve pick number and delay, and in that said microprocessor controls coupling of a signal to said storage means when said indicating means is actuated.
Claim 17
Dependent Claim
36 words
A printer as claimed in claim 12, 13, or 14, further characterised in that said microprocessor maintains and updates a table of the frequency distribution of start times in response to data from said memory means.
Claim 18
Dependent Claim
38 words
A printer as claimed in any one of claims 12 to 15, further characterised in that said microprocessor maintains and updated a table of the frequency distribution of rise times, in response to data from said memory means.
Claim 19
Dependent Claim
56 words
A printer as claimed in any one of claims 12 to 16, further characterised in that said microprocessor causes initiation of printing by said ink jet head when said memory means indicates that the rise time of pressure on said ink jet head is less than a predetermined value indicative of the maximum permissible rise time.
Claim 20
Dependent Claim
83 words
A printer as claimed in any one of claims 12 to 17, further characterised in that said microprocessor causes initiation of printing by said ink jet head after a predetermine delay when said memory means indicates that the rise time of pressure on said ink jet head is less than a first predetermined value indicative of the maximum permissible rise time and is greater than, or equal to, a second predetermined value indicative of air in the ink in said ink jet head.
Claim 21
Dependent Claim
206 words
An ink jet printer including a system for analyzing operation of the ink jet head, said system comprising: a piezoelectric crystal for sensing the pressure at an ink jet head and providing an electrical output signal proportional to the pressure sensed; a first comparator for comparing the pressure sensed by said piezoelectric crystal and a first reference level, said first comparator providing an output when said pressure sensed by said piezoelectric crystal exceeds said first reference level; a second comparator for comparing the pressure sensed by said piezoelectric crystal and a second reference level, said second comparator providing an output when said pressure sensed by said piezoelectric crystal exceeds said second reference level; a first counter connected with said first comparator for counting from initiation of start-up until said first pressure level is exceeded at said ink jet head; a second counter connected with said first and second comparators for counting from the time that said first pressure level is exceeded until said second reference level exceeds at said ink jet head; and a microcomputer connected with said first and second counters for initiating at least one of indication and correction when said count.on said counters indicates a fault in operation of said ink jet head.
Claim 22
Dependent Claim
206 words
An ink jet printer including a system for analyzing operation of the ink jet head, said system comprising: a piezoelectric crystal for sensing the pressure at an ink jet head and providing an electrical output signal proportional to the pressure sensed; a first comparator for comparing the pressure sensed by said piezoelectric crystal and a first reference level, said first comparator providing an output when said pressure sensed by said piezoelectric crystal exceeds said first reference level; a second comparator for comparing the pressure sensed by said piezoelectric crystal and a second reference level, said second comparator providing an output when said pressure sensed by said piezoelectric crystal exceeds said second reference level; a first counter connected with said first comparator for counting from initiation of start-up until said first pressure level is exceeded at said ink jet head; a second counter connected with said first and second comparators for counting from the time that said first pressure level is exceeded until said second reference level exceeds at said ink jet head; and a microcomputer connected with said first and second counters for initiating at least one of indication and correction when said count.on said counters indicates a fault in operation of said ink jet head.
Claim 23
Dependent Claim
41 words
A printer as claimed in claim 19, in which said mirco- computer includes a delay register and a rise time register for receiving and individually storing the counts on said counters, said registers being connected with said counters through logic gates.
Claim 24
Dependent Claim
138 words
An ink jet printer characterised by the provision therein of a system for analyzing operation of the printer, said printer including an ink jet head receiving ink from an ink supply through a valve controlled by a valve control unit so that ink received at said ink jet head is ejected under pressure therefrom, said system comprising first sensing means for sensing actuation of said valve control unit to open said valve and providing an output indicative thereof; second sensing means for sensing pressure build-up in said ink jet head and producing an output indicative thereof; and time lapse determining means for receiving said output from said first and second sensing means and responsive thereto producing an output indicative of the time lapse between said actuation of said valve and said pressure build-up in said ink jet head.
Claim 25
Dependent Claim
138 words
An ink jet printer characterised by the provision therein of a system for analyzing operation of the printer, said printer including an ink jet head receiving ink from an ink supply through a valve controlled by a valve control unit so that ink received at said ink jet head is ejected under pressure therefrom, said system comprising first sensing means for sensing actuation of said valve control unit to open said valve and providing an output indicative thereof; second sensing means for sensing pressure build-up in said ink jet head and producing an output indicative thereof; and time lapse determining means for receiving said output from said first and second sensing means and responsive thereto producing an output indicative of the time lapse between said actuation of said valve and said pressure build-up in said ink jet head.
Claim 26
Dependent Claim
61 words
A printer as claimed in claim 21, in which said first sensing means senses actuation of said valve control unit and responsive thereto provides an electrical output signal, and in which said second sensing means includes a pressure responsive transducer at said ink jet head, said transducer providing an electrical output signal proportional to pressure sensed in said ink jet head.
Claim 27
Dependent Claim
42 words
A printer as claimed in claim 22, in which said time lapse determining means includes counter means actuated under the control of said electrical output signal from said first and second sensing means to produce a count indicative of said time lapse.
Claim 28
Dependent Claim
113 words
A printer as claimed in claim 23, in which said time lapse determining means includes a gate connected to receive a clock input at a predetermined frequency and said electrical output signal from said first sensing means with said gate providing an output to said counter means for causing said counter means to count at said clock frequency, and a comparator for receiving a reference signal input at a predetermined level and said electrical signal output from said transducer with said comparator providing an output to said counter means to cause said count thereon to be terminated when said electrical signal output from said transducer exceeds said reference signal coupled to said comparator.
References Cited (Backward Citations)
No citation records indexed.
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