EBS
Ink-Jet Systems
®
EBS-6100 Printer User's Manual
Paragraph 4 - Operating the Printe
20070529#20.5
91
4.6.4. Information for advanced users
The printer’s maximum rate is limited only by the time that is needed to jet ink drops to
print a vertical row. This time depends on the following:
1. Ink-drop generation frequency. For the standard frequency of 62.5kHz, such drops are
generated every 16µs.
2. The number of drops per one vertical row (the drops are always counted as if all of them
were printed). The number includes the following:
● All drops for a given font size (e.g. for the 16x10 font there are 16 drops in one
vertical row),
● All drops which are jetted between the useful drops but always directed to the gutter
irrespective of what pattern is printed. For example, for the 16x10 font and a low print
rate (Speed : SLOW) every printable drop is followed by 3 drops which are directed
to the gutter. As a result, one vertical row consists of 64 drops (16+3*16) and it takes
T
tot
=1024µs (64*16µs) in total to print it. If 7-dot prints are made at a high speed,
none of the drops is directed to the gutter and therefore T
tot
=7*16µs=112µs.
In the printer, the above parameters depend on the font you have selected and on print
parameters such as Interleave, Height, Speed.
The printing of another vertical row cannot start until the printing of the previous row is
completed. This means that the time interval at which vertical rows are released for printing
cannot be shorter than the printing time referred to above.
The row release interval depends on the conveyor travel speed and resolution.
The user does not need to determine the period of time after which another vertical row
should be printed. Instead it should specify the following natural parameters:
● When an internal generator is used: Resolution, which is given as a number of dots
per centimetre (the Resol. dot/cm parametr) and conveyor travel speed, which is
given as a number of metres per minute (the Cnv spd m/min parameter). They are
used by the printer to calculate the time interval at which a row release pulse should
be generated to start printing another vertical row. If the interval is smaller than the
time needed to generate all drops to print a vertical row (see points 1, 2 above), then
the printer indicates an error. If the conveyor starts moving at the speed that is
greater than declared, then the print will stretch proportionally.
● When a shaft-encoder is used: Resolution, which is given as a number of dots per
centimetre (the Resol. dot/cm parameter) and encoder constant, which is given as a
number of pulses per metre (the Enc const p/m parameter). In this configuration the
printer “does not know” when it is likely to receive a row release pulse to start printing
another vertical row. If the pulse is generated before the printing of the previous
vertical row is completed, it must be ignored. Such a situation occurs only when the
maximum print rate is exceeded. And this occurs when greater spaces between some
rows appear.
The print rate is defined by the following formula:
V=6
*
10
5
*
(R
*
t)
-1
[m/min],
where:
R – actual resolution [dots/cm],
t – time between successive vertical rows [µs/dot].
From the above, it appears that the maximum print rate for a given resolution, R, and the total
time, T
tot
, which is needed to print a row, is defined as:
V
max
=lim 6
*
10
5
*
(R
*
t)
-1
[m/min].
t->Ttot
The value is the same irrespective of whether an internal generator or a shaft-encoder is
used.
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