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US 5,477,342 AGranted
Facsimile machine and recording control method with variable polygon mirror rotation speed
AssigneeRicoh Company, Ltd.
InventorMasaki Sato
Life of this patent
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AssigneeRicoh Company, Ltd.
InventorMasaki Sato
Estimating the term…
A facsimile machine includes a first part for emitting a scanning light beam which is used to record information, a second part for rotating a polygon mirror which reflects the scanning light beam, a third part for receiving information from a source and for detecting a communication system Group III (G3) or Group IV (G4) employed to transmit the information from the source, and a fourth part for controlling a rotational speed of the polygon mirror via the second part depending on the communication system detected by the third part.
A facsimile machine comprising:
A facsimile machine comprising:
A recording control method for controlling a recording operation of a facsimile machine which includes first means for emitting a scanning light beam which is used to record recording information, and second means for rotating a polygon mirror which reflects the scanning light beam, said recording control method comprising the steps of:
A recording control method for controlling a recording operation of a facsimile machine which includes first means for emitting a scanning light beam which is used to record recording information, and second means for rotating a polygon mirror which reflects the scanning light beam, said recording control method comprising the steps of:
A facsimile machine comprising:
A facsimile machine comprising:
A recording control method for controlling a recording operation of a facsimile machine which includes first means for emitting a scanning light beam which is used to record recording information, and second means for rotating a polygon mirror which reflects the scanning light beam, said recording control method comprising the steps of:
A recording control method for controlling a recording operation of a facsimile machine which includes first means for emitting a scanning light beam which is used to record recording information, and second means for rotating a polygon mirror which reflects the scanning light beam, said recording control method comprising the steps of:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Scanning arrangements , i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing…:…
Details of the method used: varying the scanning velocity or position
Prior to start of transmission, input or output of the picture signal only: reading or reproducing mode only, e.g. sheet size, resolution
Mode signalling or mode changing; Handshaking therefor: adapting to particular facsimile group, e.g. G3
Term ended 19 Dec 2012 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention generally relates to facsimile machines and recording control methods therefor, and more particularly to a facsimile machine which is provided with a communication means for communicating in both Group-III (G3) and Group-IV (G4) modes, and a recording control method for preventing deterioration of the image received in the G3 and G4 modes of such a facsimile machine.
According to the CCITT standards, the resolution in the main scanning direction is set to 8 lines/mm and the resolution in the sub scanning direction is set to 7.7 lines/mm or 3.85 lines/mm for the G3 mode. On the other hand, the resolution is set to 200 dots/inch (dpi) or 400 dpi for the G4 mode. The resolution of 8 lines/mm corresponds to 0.125 mm/dot, and the resolution of 7.7 lines/mm corresponds to 0.130 mm/dot. The resolution of 200 dpi corresponds to 0.127 mm/dot.
In other words, in the millimeter system, the dot width in the main scanning direction is narrower and the dot width in the sub scanning direction is wider compared to those of the inch system. Hence, the amount of information transmitted and received in the millimeter system is larger than that of the inch system for the main scanning direction and is smaller than that of the inch system for the sub scanning direction. For this reason, the line density must be switched for the case where the communication is made in the G3 mode and for the case where the communication is made in the G4 mode.
FIG. 1 is a system block diagram showing an embodiment of a facsimile machine according to the present invention;
FIG. 2 is a diagram generally showing the construction of a plotter; and
FIG. 3 is a flow chart for explaining an embodiment of a recording control method according to the present invention.
FIG.1 shows an embodiment of a facsimile machine according to the present invention. The facsimile machine shown in FIG. 1 includes a central processing unit (CPU) 1, a read only memory (ROM) 2, a random access memory (RAM) 3, an image memory 4, a communication control unit (CCU) 5, a network control unit (NCU) 6, a coder-decoder (codec) 7, a display controller 8, a scanner 9, a plotter 10 and a motor clock generation switch 11 which are coupled via a bus 12.
The CPU 1 transmits and receives information via the CCU 5 based on operation programs stored in the ROM 2. The CPU 1 also manages the image memory 4, the codec 7, the display controller 8, the scanner 9, the plotter 10 and the motor clock generation switch 11 based on the operation programs stored in the ROM 2. The CCU 5 includes the functions of communicating in both the G3 and G4 modes, and controls the transmission and reception. The NCU 6 is coupled to ISDN and PSTN lines.
For example, the plotter 10 is made up of a laser beam printer, as shown in FIG. 2 which shows an essential part of the laser beam printer. In FIG. 2, a laser beam emitted from a laser unit 21 is deflected by a polygon mirror 22 which is rotated by a polygon motor 29, and passes through a f.theta. lens system 23 in order to correct the dot intervals to a constant value. The laser beam obtained through the f.theta. lens system 23 is then reflected by a write mirror 24 and is imaged on a photosensitive (or photoconductive) body (not shown).