Apparatus and method for automatically controlling the bidirectional printing position in a serial printer

Claim 2

Apparatus according to claim 1 in which the sensing means includes a transmitting part attached to a reciprocating carriage upon which the printer head is mounted, and a receiving part attached to a main frame of the printer which is adapted to sense a signal transmitted by the transmitting part.

Claim 3

Apparatus according to claim 1 in which the sensing means includes a transmitting part attached to a main frame of the printer and a receiving part attached to a reciprocating carriage upon which the printer head is mounted and which is adapted to sense a signal transmitted by the transmitting part.

Claim 4

Apparatus according to claim 2 or claim 3 in which the error detecting means includes: means for storing a head fire position HFP and a fire time delay FTD count when the transmitted signal is sensed by the receiving part with the carriage moving in one direction; means for storing a head fire position HFP and a fire time delay FTD count when the transmitted signal is sensed by the receiving part with the carriage moving in the other direction; and position difference operating means for calculating the said one or more mechanical error factors from the stored HFP and FTD count values.

Claim 5

Apparatus according to claim 4 in which the means for storing a head fire position HFP and a fire time delay FTD count includes: adjacent position determination means for determining whether the estimated head position has reached the head fire position HFP corresponding to a first adjacent position; counter operating means for initialising a fire time delay FTD counter when the estimated head position has reached the head fire position HFP corresponding to the first adjacent position and starting the operation of the counter; head fire position increase determination means for determining whether the value of the fire time delay FTD count exceeds a head fire position value and, if so, incrementing the HFP and resetting the FTD counter; sensing determination means for determining whether the signal from the transmitting part of the sensor is sensed by the receiving part; and storing means for storing the head fire position HFP when the said signal is sensed by the said receiving part and storing the fire time delay FTD count.

Claim 6

Apparatus according to claim 4 or claim 5 in which the means for storing a head fire position HFP and a fire time delay FTD count includes: adjacent position determination means for determining whether the estimated head position has reached the head fire position HFP corresponding to a second adjacent position; counter operating means for initializing the fire time delay FTD counter when the estimated head position has reached the head fire position corresponding to the second adjacent position and starting the operation of the counter; head fire position HFP increase determination means for determining whether the value of the fire time delay counter exceeds a head fire position value and, if so, incrementing the HFP and resetting the FTD counter; sensing determination means for determining whether the signal from the transmitting part of the sensor is sensed by the receiving part; and storing means for storing the head fire position HFP when the said signal is sensed by the said receiving part and storing the fire time delay FTD count.

Claim 7

Apparatus according to claim 5 in which means for controlling the motion of the printer head are provided, including: return position determination means for determining whether the estimated position of the printer head has reached a head fire position HFP corresponding to a return position; and moving means for moving the carriage reversely when that condition is met.

Claim 8

Apparatus according to claim 6 in which means for controlling the motion of the printer head are provided, including: start position determining means for determining whether the estimated position of the printer head has reached a head fire position HFP corresponding to a start position; and stopping means for stopping the carriage when that condition is met.

Claim 9

Apparatus according to any one of claims 4-8 in which the position difference operating means calculates a head fire position HFP difference and a fire time delay FTD difference using the stored HFP and FTD values.

Claim 10

Apparatus according to claim 9 in which the printing means includes: clock generating means for generating a clock; print starting signal generating means for generating a print starting signal by determining the estimated position of the printing head using the clock signal generated by the clock generating means; enable signal generating means for generating an enable signal by determining the correct printing time in compliance with the fire time delay FTD difference using the clock generated by the clock generating means.

Claim 11

Apparatus according to claim 10 in which the print starting signal generating means includes: DPI dividing means for dividing the clock according to the DPI (Dot Per Inch) supported by the serial printer system; head time dividing means for dividing again the divided clock to generate the standard clock frequency per nozzle from the clock divided by the DPI dividing means; a head time counter for counting the head time based on the clock divided by the head time dividing means; a first comparator for generating a head fire standard clock by comparing the value counted by the head time counter with a predetermined value; position dividing means for generating a clock for controlling operation of the printer motor using the clock generated by the clock generating means; a position up/down counter for performing a counting operation to seek the present position of the printer head using the clock divided by the position dividing means; a second comparator for detecting the estimated head position using the said predetermined value; a head fire position HFP difference input means for receiving the calculated difference of the head fire position HFP; and a third comparator for generating the printing signal delayed by as much as the head fire position HFP difference by comparing the value of the estimated head position with the head fire position HFP difference stored in the print starting position register.

Claim 12

Apparatus according to claim 10 or claim 11 in which the enable signal generating means includes: resolution dividing means for dividing the clock generated by the clock generating means according to the printing resolution; a fire time delay FTD counter for counting the clock divided by the resolution dividing means; a fire time delay FTD difference input means for receiving the head time delay FTD difference; and a fourth comparator for generating an enable signal by delaying the fire time by as much as the fire time delay FTD difference, using the value counted by the FTD counter.

Claim 13

Apparatus according to any one of claims 10-12 in which the printing means includes: a fifth comparator for comparing the print starting signal with the enable signal generated by said enable signal generating means; and head driving means for driving the printer head according to the signal output from the fifth comparator, to perform the printing operation delayed sufficiently to compensate for the mechanical error.

Claim 14

A bidirectional serial printer as described with reference to and as illustrated in Figs. 3 et seq. of the accompanying drawings.

Claim 16

A method according to claim 15 further including: determining whether the estimated head position has reached the head fire position HFP corresponding to a first adjacent position; initialising a fire time delay FTD counter when the estimated head position has reached the head fire position HFP corresponding to the first adjacent position and starting the operation of the counter; determining whether the value of the fire time delay FTD count exceeds a head fire position value and, if so, incrementing the HFP and resetting the FTD counter; determining whether the signal from the transmitting part of the sensor is sensed by the receiving part; and storing the head fire position HFP when the said signal is sensed by the said receiving part and storing the fire time delay FTD count.

Claim 17

A method according to claim 15 or claim 16 further including: determining whether the estimated head position has reached the head fire position HFP corresponding to a second adjacent position; initializing the fire time delay FTD counter when the estimated head position has reached the head fire position corresponding to the second adjacent position and starting the operation of the counter; determining whether the value of the fire time delay counter exceeds a head fire position value and, if so, incrementing the HFP and resetting the FTD counter; determining whether the signal from the transmitting part of the sensor is sensed by the receiving part; and storing the head fire position HFP when the said signal is sensed by the said receiving part and storing the fire time delay FTD count.

Claim 18

A method according to claim 16 further comprising: determining whether the estimated position of the printer head has reached a head fire position HFP corresponding to a return position; and moving the carriage reversely when that condition is met.

Claim 19

A method according to claim 17 further comprising: determining whether the estimated position of the printer head has reached a head fire position HFP corresponding to a start position; and stopping the carriage when that condition is met.

Claim 20

A method according to claim of claim 16 in which the head fire position HFP difference and the fire time delay FTD difference are obtained using the stored HFP and FTD values.