Method and device for controlling vertical scan speed

Claim 3

A control method of a vertical scan speed according to claim 1, wherein transmission to said recording medium is made by scanning said document in a.main scan direction to generate video signals in the scan line unit, moving relatively said document and a light receiving portion in the vertical scan direction to read said document and to generate plane-wise said video signals, subjecting said video signals to redundancy reduction encoding in the scan line unit, storing said redundancy reduction codes said code buffer memory and then transmitting said codes.

Claim 4

A control method of a vertical scan speed according to claim 1 wherein receipt for said recording medium is made by storing the received codes in said Code buffer memory, decoding said codes and converting them to said video signals, recording said video signals in the scan line unit in the main scan direction, and moving relatively a recording head and recording paper in the vertical scan direction to effect recording plane-wise.

Claim 5

A control method of a vertical scan speed according to claim 1 wherein said vertical scan speed is gradually changed at the time of shift of said vertical scan modes in such a manner that the acceleration of the vertical scan speed is below a predetermined level.

Claim 6

A control method of a vertical scan speed according to claim 3 wherein recording to said recording medium is effected in the highest speed vertical scan speed mode irrel- vantly to the number of the buffered code bits after the last code of a page is received.

Claim 7

A control method of a vertical scan speed according to claim 3, wherein the application time of a current to said recording head for printing in the scan line unit is different in accordance with the content of said video signals of the scan line to be recorded; the vertical scan speed is divided in advance into V o (stop) < v 1 < ... < VNso that the acceleration of the vertical scan speed is below a predetermined level, and is changed only one stage by one; and the control of the vertical scan speed further is effected by a first vertical scan mode wherein when the vertical scan speed of an original scan line and that of a next scan line are assumed to be V i and V i+1 , respectively, and when the vertical scan speed of the next scan line and so forth are decelerated one stage by one, the vertical speed is accelerated and the vertical scan speed of the next scan line is set to V i+1 if there does not exist any scan line having a printing speed lower than the vertical scan speed, and when the vertical scan speed of the next scan line is assumed to be V . in cases other than the case described above and when the vertical scan speeds of the next scan line and so forth are decelerated one stage by one and when there does not exist any scan line having a printing speed lower than the vertical scan speed, the vertical scan speed of the next scan line is set to V i (uniform speed) and the vertical scan speed of the next scan line is decelerated to V i-l in cases other than the two cases described above; and a second vertical scan mode wherein the vertical scan speed is set below the lowest printing speed.

Claim 8

A device for controlling a vertical scan speed for carrying out a method according to claim 1, comprising a line buffer memory (50; 1030) for storing read or received information signals from a document; a code buffer memory (70; 1010) for storing coded signal bits corresponding to the read or received information signals; control means (90; 94; 200; 1060) for setting vertical scan speed values in accordance with the number of buffered code bits in said code buffer memory and/or the buffered information signals in at least a first vertical scan mode and a second vertical scan mode and for changing the mode from said first vertical scan mode to said second vertical scan mode when the number of the buffered code bits in said code buffer memory reaches a first reference value; and for changing the mode from said second vertical scan mode to said first vertical scan mode when the number of the buffered code bits in said code buffer memory reaches 'a second reference value which is different from said first reference value.