EP0043913A2
Expired / Lapsed
EP
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Apparatus for and method of controlling the temperature of a hot roll fuser in a xerographic machine
Assignee: International Business Machines Corp
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Filing: 1981-06-10
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Granted: —
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Expires: 2001-06-10
Abstract
Abstract When a xerographic machine is switched on, a hot roll temperature control system initiates heating of the roll to a first temperature 21. At the end of a first predetermined period (44) from switch-on, if the roll has not reached the first temperature, indicating that the machine has been started from cold, the control system initiates heating of the roll to a second, higher, temperature 45. If the switch-on is after a temporary period of non-use of the machine, the hot roll will reach the first temperature within the first period, in which case that temperature is maintained. At the end of a second period (46), if the second temperature is being employed, then it is reduced to the first temperature. The machine senses whether first or second, larger, copy sheets are to be used and, whenever the larger sheets are used, increases the current roll temperature by a predetermined amount (55).
Inventors
- 👤 Robert Clark Brannan
- 👤 Robert John Fogoros
- 👤 Michael Ray Headrick
- 👤 Ainis Krumins
- 👤 Robert Franklin Pryor
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 13:43
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/20; G03G15/2003; G03G15/2014; G03G15/2039; G03G15/205
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
179 words
A xerographic machine including a hot roll fuser, a control system for the hot roll fuser and a main switch which, when opened, removes power from at least some components, including the fuser, of the machine, said control system including timing means for defining a first period immediately following closure of the main switch, a generator operable to produce an output signal indicative of a required hot roll temperature and a comparison network operable to compare said output signal with a sensor signal indicating the actual temperature of the hot roll to produce a ready signal upon equality of the output and sensor signals, said generator being operative, immediately after closure of the main switch to produce an output signal indicative of a first required hot roll temperature and, if said ready signal appears within said first period, to maintain the output signal unchanged, but if said ready signal appears subsequent to said first period, to alter the output signal to a signal indicative of a second, higher, required hot roll temperature upon the occurrence of the ready signal.
Claim 2
Dependent Claim
179 words
A xerographic machine including a hot roll fuser, a control system for the hot roll fuser and a main switch which, when opened, removes power from at least some components, including the fuser, of the machine, said control system including timing means for defining a first period immediately following closure of the main switch, a generator operable to produce an output signal indicative of a required hot roll temperature and a comparison network operable to compare said output signal with a sensor signal indicating the actual temperature of the hot roll to produce a ready signal upon equality of the output and sensor signals, said generator being operative, immediately after closure of the main switch to produce an output signal indicative of a first required hot roll temperature and, if said ready signal appears within said first period, to maintain the output signal unchanged, but if said ready signal appears subsequent to said first period, to alter the output signal to a signal indicative of a second, higher, required hot roll temperature upon the occurrence of the ready signal.
Claim 3
Dependent Claim
62 words
A xerographic machine as claimed in claim 1 including further timing means for defining a second period immediately following production of said ready signal, said generator, if it had altered its output signal upon occurrence of the ready signal, being operative to return the signal to that indicative of said first required hot roll temperature at the termination of the second period.
Claim 4
Dependent Claim
75 words
A xerographic machine as claimed in claim 2 in which said further timing means defines two sub-periods within the second period and the generator is operative to return the sigrnal in two steps from said signal indicative of said second-required het roll temperature to an intermediate level at the end of the first of- said sub-periods and to said signal indicative of the first required hot roll temperature at the end of the second sub-period.
Claim 5
Dependent Claim
58 words
A xerographic machine as claimed in any of the previous claims capable of producing copies on sheets of two different sizes, said generator being responsive to signals indicating.selection of the longer of the sizes to alter the output signal to increase the required hot roll temperature by a predetermined amount during production of copies on the larger sheets.
Claim 6
Dependent Claim
51 words
A xerographic machine as claimed in claim 4 in which the alteration of the output signal for the larger sheets is maintained for a period, calculated prior to completion of copying on the larger sheets, which is a function of the number of copies to be produced on the larger sheets.
Claim 7
Independent Claim
91 words
A method of controlling the temperature of the hot roll of a hot roll fuser in a xerographic machine, comprising the steps of sensing switch-on of the machine and, in response to such sensing, initiating heating of the hot roll towards a first predetermined temperature, defining a first period from said sensing and, at the end of the first period either maintaining the hot roll at said first predetermined temperature if it has reached that temperature or, if not, initiating heating of the hot roll 'towards a second, higher, predetermined temperature.
Claim 8
Independent Claim
91 words
A method of controlling the temperature of the hot roll of a hot roll fuser in a xerographic machine, comprising the steps of sensing switch-on of the machine and, in response to such sensing, initiating heating of the hot roll towards a first predetermined temperature, defining a first period from said sensing and, at the end of the first period either maintaining the hot roll at said first predetermined temperature if it has reached that temperature or, if not, initiating heating of the hot roll 'towards a second, higher, predetermined temperature.
Claim 9
Dependent Claim
60 words
A method as claimed in claim 6 including a further step of defining a second predetermined period from the end of the first period and, if the hot roll temperature is not maintained at the first temperature aL the end of the first period, initiating reduction of its temperature to the first temperature at the end of the second period.
Claim 10
Dependent Claim
57 words
A method as claimed in claim 6 or claim 7 including the step of sensing whether copies are to be produced on first or second, larger size, sheets by the machine and, after the end of said first period, increasing the temperature of the hot roll by a predetermined amount during production of copies on the'second sheets.
References Cited (Backward Citations)
No citation records indexed.
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