Patent US5373518A successfully refreshed from Google Patents.
US5373518A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Image forming apparatus and constant current circuit switching device for use therewith
Assignee: Canon Inc
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Filing: 1993-03-22
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Granted: 1994-12-13
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Expires: 2013-03-22
Abstract
Abstract A driver IC for driving a light source comprises means for generating a constant current, switching means for switching the constant current supplied to the light source, first input terminal for inputting a first signal to modulate a light emitted by the light source, said switching means performing a switching operation in accordance with the first signal, and second input terminal for inputting a second signal so as to supply the constant current to the light source, irrespective of the first signal.
Inventors
- 👤 Seiji Uchiyama
- 👤 Akio Noguchi
- 👤 Yukihide Ushio
- 👤 Shimpei Matsuo
- 👤 Yoji Serizawa
- 👤 Kazuro Yamada
- 👤 Makoto Takeuchi
- 👤 Hiroyuki Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:22
CPC Classifications
G; G06; G06K; G06K15/00; G06K15/02; G06K15/12; G06K15/1204; G06K15/1209; G06K15/1214; H; H01; H01S; H01S5/00; H01S5/04; H01S5/042; H01S5/06; H01S5/062; H01S5/06209; H01S5/06213; H01S5/0427
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
100 words
A driver IC for driving a light source comprising: generating means for generating a constant current; switching means for switching the constant current so as to be supplied to the light source; a first input terminal functionally connected to said switching means for inputting a first signal to modulate light emitted by the light source, said switching means performing a switching operation in accordance with the first signal; and a second input terminal functionally connected to said switching means for inputting a second signal so as to supply the constant current to the light source, irrespective of the first signal.
Claim 2
Dependent Claim
100 words
A driver IC for driving a light source comprising: generating means for generating a constant current; switching means for switching the constant current so as to be supplied to the light source; a first input terminal functionally connected to said switching means for inputting a first signal to modulate light emitted by the light source, said switching means performing a switching operation in accordance with the first signal; and a second input terminal functionally connected to said switching means for inputting a second signal so as to supply the constant current to the light source, irrespective of the first signal.
Claim 3
Dependent Claim
41 words
The driver IC according to claim 1, further comprising a third input terminal functionally connected to said switching means for inputting a third signal so as to cut the constant current supplied to the light source, irrespective of the first signal.
Claim 4
Dependent Claim
44 words
The driver IC according to claim 1, further comprising a fourth input terminal functionally connected to said generating means for inputting an analog control signal, wherein said generating means generates the current supplied to said light source in accordance with the analog control signal.
Claim 5
Dependent Claim
63 words
A laser control unit for modulating a light beam emitted from a semiconductor laser based on image information, comprising: first input means for inputting image information for modulating the light beam, the image information being directly transferred from a data source via a predetermined transmission medium; and second input means for inputting an image control signal which controls modulation by the image information.
Claim 6
Dependent Claim
63 words
A laser control unit for modulating a light beam emitted from a semiconductor laser based on image information, comprising: first input means for inputting image information for modulating the light beam, the image information being directly transferred from a data source via a predetermined transmission medium; and second input means for inputting an image control signal which controls modulation by the image information.
Claim 7
Dependent Claim
59 words
The laser control unit according to claim 4, further comprising: process means for processing the image information and the image control signal; generating means for generating a drive current to be supplied to said semiconductor laser; and means for switching the supply to said drive current to the semiconductor laser based on an output signal of said process means.
Claim 8
Dependent Claim
27 words
The laser control unit according to claim 4, wherein said image control signal is an image formation authorized signal for authorizing the modulation with said image information.
Claim 9
Dependent Claim
25 words
The laser control unit according to claim 4, wherein said image control signal is a forced light-up signal for forcedly lighting up the semiconductor laser.
Claim 10
Dependent Claim
17 words
The laser control unit according to claim 5, wherein said process means has a standard logic circuit.
Claim 11
Dependent Claim
16 words
The laser control unit according to claim 5, wherein said process means is constituted of transistors.
Claim 12
Dependent Claim
19 words
The laser control unit according to claim 5, wherein said laser control unit is made on a single substrate.
Claim 13
Dependent Claim
18 words
The laser control unit according to claim 5, wherein said laser control unit is a one-chip integrated circuit.
Claim 14
Dependent Claim
18 words
The laser control unit according to claim 4, wherein said predetermined transmission medium is a twisted pair cable.
Claim 15
Dependent Claim
17 words
The laser control unit according to claim 4, wherein said predetermined transmission medium is a coaxial cable.
Claim 16
Dependent Claim
17 words
The laser control unit according to claim 4, wherein said predetermined transmission medium is a straight cable.
Claim 17
Dependent Claim
76 words
An image processing apparatus comprising: a first unit for generating an image control signal; a second unit for generating an image signal; a third unit for generating a drive signal for a light source based on said image signal and said image control signal; and a transmission medium for directly transferring said image signal between the second and third units; wherein said third unit has means for processing the image signal and the image control signal.
Claim 18
Dependent Claim
76 words
An image processing apparatus comprising: a first unit for generating an image control signal; a second unit for generating an image signal; a third unit for generating a drive signal for a light source based on said image signal and said image control signal; and a transmission medium for directly transferring said image signal between the second and third units; wherein said third unit has means for processing the image signal and the image control signal.
Claim 19
Dependent Claim
18 words
The image processing apparatus according to claim 15, wherein said predetermined transmission medium is a twisted pair cable.
Claim 20
Dependent Claim
17 words
The image processing apparatus according to claim 15, wherein said predetermined transmission medium is a coaxial cable.
Claim 21
Dependent Claim
17 words
The image processing apparatus according to claim 15, wherein said predetermined transmission medium is a straight cable.
Claim 22
Dependent Claim
50 words
The image processing apparatus according to claim 15, wherein said third unit further includes means for generating a constant current to be supplied to the light source, and means for switching the constant current to the light source based on the image signal, and is made on a single substrate.
Claim 23
Dependent Claim
50 words
The image processing apparatus according to claim 15, wherein said third unit further includes means for generating a constant current to be supplied to the light source, and means for switching the constant current to the light source based on the image signal, and is formed as an one-chip IC.
Claim 24
Dependent Claim
21 words
The image processing apparatus according to claim 15, wherein said second unit is provided outside of a body of the apparatus.
Claim 25
Dependent Claim
20 words
The image processing apparatus according to claim 15, wherein said first and second units are constituted as a single unit.
Claim 26
Dependent Claim
92 words
A driver apparatus for switching a supply current to a driving object based on an input signal, comprising: a first constant current source for generating a first constant current; a second constant current source for generating a second constant current; first switching means for switching the supply of said first constant current to said driving object; and second switching means for switching said second constant current in accordance with said input signal; wherein said first switching means performs the switching operation in accordance with the switching state of said second switching means.
Claim 27
Dependent Claim
92 words
A driver apparatus for switching a supply current to a driving object based on an input signal, comprising: a first constant current source for generating a first constant current; a second constant current source for generating a second constant current; first switching means for switching the supply of said first constant current to said driving object; and second switching means for switching said second constant current in accordance with said input signal; wherein said first switching means performs the switching operation in accordance with the switching state of said second switching means.
Claim 28
Dependent Claim
17 words
The driver apparatus according to claim 23, wherein said first switching means has a current mirror circuit.
Claim 29
Dependent Claim
14 words
The driver apparatus according to claim 23, wherein said second switching means has transistors.
Claim 30
Dependent Claim
20 words
The driver apparatus according to claim 23, wherein said first constant current is substantially equal to said second constant current.
Claim 31
Dependent Claim
34 words
The driver apparatus according to claim 23, wherein a constant voltage source is interposed between said first current source and a ground level and/or between said second constant current source and the ground level.
Claim 32
Dependent Claim
17 words
The driver apparatus according to claim 27, wherein said constant voltage source is one or more diodes.
Claim 33
Dependent Claim
44 words
The driver apparatus according to claim 23, further comprising third switching means for switching in accordance with the switching state of said second switching means, wherein said first switching means performs the switching in accordance with the switching state of said third switching means.
References Cited (Backward Citations)
US4695714A
Cited
US4819242A
Cited
US4878225A
Cited
EP0307980A2
Cited
US4899344A
Cited
US5043745A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-12-12 | 1998-06-13 | 1998-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-12-12 | 2002-06-13 | 2002-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-12-12 | 2006-06-13 | 2006-12-13 | $7700.00 | Window Closed / Lapsed |