# US 5,353,048 A · Image recording apparatus

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- Number: US 5,353,048 A
- Document ID: US5353048A
- Status: Granted
- Kind: A
- Application number: 07/873,755
- Filed: 1992-04-27
- Granted: 1994-10-04
- Earliest claimed: 1991-04-30
- Assignees: Fuji Xerox Co., Ltd.
- Inventors: Makoto Kanai
- Web page: https://patentgrep.com/patent/US5353048A

## CPC

- H04N 1/0411: {in the main scanning direction}
- G06K 15/1209: {Intensity control of the optical beam (G06K15/1223 takes precedence)}
- H04N 1/0402: {Scanning different formats; Scanning with different densities of dots per unit length, e.g. different numbers of dots per inch (dpi); Conversion of scanning standards (H04N1/00283 takes precedence; picture signal circuits for modification of image resolution H04N1/3935, H04N1/40068)}
- H04N 1/0446: {Varying the modulation time or intensity}
- H04N 1/053: in main scanning direction, e.g. synchronisation of line start or picture elements in a line
- H04N 1/4076: {dependent on references outside the picture}
- H04N 1/1135: {for the main-scan only}
- H04N 1/12: using the sheet-feed movement {or the medium-advance or the drum-rotation movement} as the slow scanning component, {e.g. arrangements for the main-scanning}({sheet-feed movement by translatory movement of a flat picture-bearing surface H04N1/1008; main-scanning using oscillating or rotating mirrors H04N1/113; } using multi-element arrays H04N1/19)
- H04N 2201/02439: Positioning method
- H04N 2201/0471: using dedicated detectors
- H04N 2201/04732: Detecting at infrequent intervals, e.g. once or twice per line for main-scan control
- H04N 2201/04744: by detecting the scanned beam or a reference beam
- H04N 2201/04767: by controlling the timing of the signals, e.g. by controlling the frequency o phase of the pixel clock
- H04N 2201/04794: Varying the control or compensation during the scan, e.g. using continuous feedback or from line to line
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS

## Abstract

An image recording apparatus such as a laser printer in which a beam from a laser source is deflected by a deflector such as a rotating polygon mirror and a surface to be scanned is scanned by such deflected beam. The image recording apparatus includes a light source for outputting a beam, a deflection unit for deflecting the beam in predetermined directions to scan a scanning surface, a beam detection unit for receiving the beam deflected by the deflection unit to set a reference timing every scanning operation, and a beam intensity switching unit for controlling the light source to switch an intensity of the beam by a plurality of degrees.

## Claims

### Claim 1

An image recording apparatus comprising:
a light source for outputting a beam;
deflection means for deflecting the beam in predetermined directions to scan a scanning surface;
beam detection means for receiving the beam deflected by said deflection means to set a reference timing every scanning operation; and
beam intensity switching means for controlling said light source to switch an intensity of the beam irradiated to said beam detection means and an intensity of the beam scanned on the scanning surface by a plurality-of degrees.

### Claim 2 (depends on 1)

The image recording apparatus according to claim 1, wherein the intensity of the beam irradiated to said beam detection means is greater than the intensity of the beam scanned on the scanning surface.

### Claim 3

An image recording apparatus comprising:
a light source for outputting a beam;
deflection means for deflecting the beam in predetermined directions to scan a scanning surface;
beam detection means for receiving the beam deflected by said deflection means to set a reference timing every scanning operation;
beam intensity switching means for controlling said light source to switch an intensity of the beam by a plurality-of degrees; and wherein said light source stops output of the beam after a first predetermined time elapses from the reference timing set by said beam detection means, and restarts output of a beam of which intensity is smaller than that prior to stopping output of the beam after a second predetermined time elapses from the reference timing.

### Claim 4 (depends on 1)

The image recording apparatus according to claim 1, further comprising modulation means for modulating the beam outputted from said light source.

### Claim 5 (depends on 1)

The image recording apparatus according to claim 1, wherein said light source includes a laser oscillator.

### Claim 6 (depends on 1)

The image recording apparatus according to claim 1, wherein said deflection means includes a polygon mirror.