US4941004A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Printer apparatus
Assignee: Eastman Kodak Co
•
Filing: 1989-03-08
•
Granted: 1990-07-10
•
Expires: 2009-03-08
Abstract
Abstract An improved printer apparatus includes a print head having a series of point-like radiation sources, such as LED's, arranged in a row for exposing a recording medium. Logic means is provided for determining which of the point-like radiation sources are to be selected for energization. A current driver means responsive to the logic means provides electrical current to the radiation sources selected. A current driver means include a current mirror having a master circuit for generating a reference current and a plurality of slave circuits for providing respective driver currents to the radiation sources selected for energization. The master circuit includes a resistor of the type that at least prior to adjustment permits for substantially continuous adjustment of driver current over a range of resistance values. Two independent power supplies are provided to the print head. One power supply provides electrical energy for the logic device at a fixed voltage suitable for the logic devices. A second power supply provides the electrical energy for illuminating the point-like radiation sources. Thus, power to the logic devices is isolated from noise generated during energization of the point-like radiation sources. A variable voltage is provided by this second power supply to permit for flexibility in adjustment of the currents to the point-like radiation sources. This variable voltage may be adjusted in response to aging of the LED's or temperature of the print head.
Inventors
- 👤 Hieu T. Pham
- 👤 Yee S. Ng
- 👤 Kenneth D. Kieffer
- 👤 Pin S. Tschang
- 👤 Eric K. Zeise
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:26
CPC Classifications
G; G06; G06K; G06K15/00; G06K15/02; G06K15/12; G06K15/1238; G06K15/1242; G06K15/1247
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
179 words
In a printing apparatus for exposing a light sensitive recording medium; a print head including a series of point-like radiation sources arranged in a row for exposing the medium; means for moving the medium relative to the print head; means providing data signals representing data to be printed; logic means responsive to the data signals for determining which of the point-like radiation sources are to be selected for energization; current driver means responsive to the logic means for providing electrical current to the radiation sources selected for energization; the improvement which comprises: wherein the current driver means includes a current mirror having a master circuit for generating a reference current and a plurality of slave circuits for providing respective driver currents to the radiation sources selected for energization; the master circuit being characterized by a resistor means of the type that at least prior to final adjustment permits for adjustment of driver currents through change of resistance values and wherein the master circuit further includes a variable voltage source for also permitting adjustment of the levels of driver currents.
Claim 2
Dependent Claim
179 words
In a printing apparatus for exposing a light sensitive recording medium; a print head including a series of point-like radiation sources arranged in a row for exposing the medium; means for moving the medium relative to the print head; means providing data signals representing data to be printed; logic means responsive to the data signals for determining which of the point-like radiation sources are to be selected for energization; current driver means responsive to the logic means for providing electrical current to the radiation sources selected for energization; the improvement which comprises: wherein the current driver means includes a current mirror having a master circuit for generating a reference current and a plurality of slave circuits for providing respective driver currents to the radiation sources selected for energization; the master circuit being characterized by a resistor means of the type that at least prior to final adjustment permits for adjustment of driver currents through change of resistance values and wherein the master circuit further includes a variable voltage source for also permitting adjustment of the levels of driver currents.
Claim 3
Dependent Claim
36 words
The apparatus of claim 1 and including automatic adjustment means for sensing the need for adjustment of driver currents and for providing adjustment in said currents by changing the level of current in the reference current.
Claim 4
Dependent Claim
21 words
The apparatus of claim 2 and wherein the automatic adjustment means includes means for sensing the temperature of the print head.
Claim 5
Dependent Claim
26 words
The apparatus of claim 3 and wherein the variable voltage source is provided by a power supply independent of a power supply for the logic means.
Claim 6
Dependent Claim
25 words
The apparatus of claim 2 wherein the variable voltage source is provided by a power supply independent of a power supply for the logic means.
Claim 7
Dependent Claim
26 words
The apparatus of claim 1 and wherein the variable voltage source is provided by a power supply independent of a power supply for the logic means.
Claim 8
Dependent Claim
180 words
In a printing apparatus for exposing a light sensitive recording medium; a print head including a series of point-like radiation sources arranged in a row for exposing the medium; means for moving the medium relative to the print head; means providing data signals representing data to be printed; logic means responsive to the data signals for determining which of the point-like radiation sources are to be selected for energization; current driver means responsive to the logic means for providing electrical current to the radiation sources selected for energization; the improvement which comprises: wherein the current driver means includes a current mirror having a master circuit for generating a reference current and a plurality of slave circuit for providing respective driver currents to the radiation sources selected for energization; the master circuit being characterized by an adjustable conducting means of the type that at least prior to final adjustment permits for adjustment of driver currents through change of conductivity values and wherein the master circuit further includes a variable voltage source for also permitting adjustment of the levels of driver currents.
Claim 9
Dependent Claim
180 words
In a printing apparatus for exposing a light sensitive recording medium; a print head including a series of point-like radiation sources arranged in a row for exposing the medium; means for moving the medium relative to the print head; means providing data signals representing data to be printed; logic means responsive to the data signals for determining which of the point-like radiation sources are to be selected for energization; current driver means responsive to the logic means for providing electrical current to the radiation sources selected for energization; the improvement which comprises: wherein the current driver means includes a current mirror having a master circuit for generating a reference current and a plurality of slave circuit for providing respective driver currents to the radiation sources selected for energization; the master circuit being characterized by an adjustable conducting means of the type that at least prior to final adjustment permits for adjustment of driver currents through change of conductivity values and wherein the master circuit further includes a variable voltage source for also permitting adjustment of the levels of driver currents.
Claim 10
Dependent Claim
35 words
The apparatus of claim 7 including automatic adjustment means for sensing the need for adjustment of driver currents and for providing adjustment in said currents by changing the level of current in the reference current.
Claim 11
Dependent Claim
21 words
The apparatus of claim 8 and wherein the automatic adjustment means includes means for sensing the temperature of the print head.
Claim 12
Dependent Claim
26 words
The apparatus of claim 9 and wherein the variable voltage source is provided by a power supply independent of a power supply for the logic means.
Claim 13
Dependent Claim
26 words
The apparatus of claim 8 and wherein the variable voltage source is provided by a power supply independent of a power supply for the logic means.
Claim 14
Dependent Claim
26 words
The apparatus of claim 7 and wherein the variable voltage source is provided by a power supply independent of a power supply for the logic means.
References Cited (Backward Citations)
US3947840A
Cited
US4216393A
Cited
US4417240A
Cited
GB2104266A
Cited
US4455562A
Cited
JPS5973983A
Cited
US4524372A
Cited
US4525729A
Cited
DE3422907A1
Cited
US4596995A
Cited
US4590487A
Cited
US4571602A
Cited
US4575739A
Cited
US4653895A
Cited
JPS61185981A
Cited
WO1987002162A1
Cited
US4831392A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-09 | 1994-01-08 | 1994-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-09 | 1998-01-08 | 1998-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-09 | 2002-01-08 | 2002-07-10 | $7700.00 | Window Closed / Lapsed |