JPS5931949B2 - inkjet plotter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a printing head having a plurality of nozzles arranged perpendicularly or obliquely to the scanning direction of a carriage, or a printing head having a plurality of nozzles arranged perpendicularly or obliquely to the scanning direction of the carriage. Regarding an inkjet plotter, in which a printing head having a single multi-value deflection type nozzle is mounted on a carriage, and the carriage is moved relative to a recording medium to perform printing, in particular, the previous printing head in the feeding direction of the recording medium is A selection circuit is provided for overlapping at least one dot between the lowest printing portion at the time of printing and the topmost printing portion at the next printing, and selecting an ink droplet to print the overlapping portion,
This prevents white streaks and black streaks from occurring at the seam between the previous printing and the next printing.

In a carriage scanning type inkjet printer, the carriage moves and prints one printing section, then steps the printing paper at right angles to the direction of carriage movement, stops at the next printing section, and prints the next printing section. However, when the printing paper is fed, it stops slightly shifted from the normal feeding position due to motor hunting or errors in detecting the position of the recording medium. The seams of the prints did not match the next time the carriage was moved, resulting in white or black lines, which were undesirable in the image.

FIG. 1 is a diagram showing white stripes and black stripes in a charge deflection type multi-inkjet plotter. FIG. 1A shows the white stripes, and FIG. 1B shows the black stripes.

In order to eliminate white streaks and black streaks in a charge deflection type multi-ink jet plotter as described above, the present applicant previously proposed a joint part as shown in FIG. 2A or B.
We proposed an inkjet plotter that prints at least one dot over each line alternately to make the joints less noticeable and improve image quality. FIG. 3 is a diagram showing an example of an electric circuit for printing the dots shown in FIG. , 15 is an AND circuit, 4 is a binary counter, 6 is a monomulti circuit, T is an inverter, 9 is an OR circuit, 11 is a 1-line memory,
12 is clock B whose timing is slightly different from clock A.
13 is a latch circuit,
14 is a shift register, and 16 is a charged electrode array.

FIG. 5 is a signal waveform diagram of each part in FIG.
The case of 0 stage is shown. The operation will be explained below with reference to this. Input the clock A signal into sexagesimal counter 2,
Output b rises at the 59th pulse and falls at the 60th pulse, and output j rises at the 60th pulse and falls at the next pulse. By ANDing the signals A and b in the AND circuit 3, the 60th pulse c is obtained. In this c,
If the binary counter 4 is set or reset alternately and the output d and c are ANDed by the AND circuit 5, 60
The second pulse appears every other time (e). This pulse e resets the monomulti 6 to obtain a signal f that nullifies the (60n+1)th pulse. On the other hand, when b is the signal passed through inverter 7 and a is ANDed, the clock g whose 60nth clock is missing is extracted, and this pulse g(5
When e is input to the OR circuit 9, a 60-pulse train and a 59-pulse train (the 60th one is missing) are obtained alternately (h), and this pulse train h is ANDed with the output f of the monomulti 6, and (6
When the 0n+1)-th pulse is disabled, a 60-pulse train and a 58-pulse train (that is, a clock with the (60n+1)-th and the next 60n-th missing) are generated alternately.Use this as the clock input of the 1-line memory 11, Outputs memory contents every clock. This is clock B, which has a slightly different timing from clock A (no missing clocks).
As a result, the latch circuit 13 latches the signal. In addition, a sexagenary signal j is input into the shift register 14 to obtain an output every 60 pulses, and this is ANDed with the signal from the latch circuit in an AND circuit 15, and the charged electrode array 16 is driven to control the nozzle. Select the print from . 60 pulse trains and 5
Since the eight pulse trains (the 1st and 60th pulses are missing) occur alternately, if there is an odd number of nozzles, each of them will be printed and a printed image as shown in FIG. 2 will be obtained.

If the number of nozzles is even, the same result can be obtained by inputting a line end signal to the binary counter 4 and inverting it. FIG. 4 is a diagram showing another example, in which the same reference numerals as in FIG. 3 represent the same things.

17 and 18 are AND circuits, 19 is a binary counter, 20,
22 is an inverter, 21 and 24 are OR circuits, and 23 is a delay circuit.

FIG. 6 is a signal waveform diagram of each part in the embodiment of FIG. 4. Signal a' of clock A is input into sexagesimal counter 2, and signal d' falls at the 59th pulse and rises at the 60th pulse, and signal f falls at the 60th pulse and rises at the next pulse. 'make.

A binary counter 19 uses the line end signal b' as a clock.
The output C1' of this binary counter 19 is delayed by a certain fixed time Td (a time greater than 1 clock and less than 60 clocks) by the delay circuit 23, and the output C1' of this delay circuit and the output C1' of the binary counter 19 are The OR circuit 24 obtains the logical sum C2' with the output c{ of , and inputs the output ♂2 of the OR circuit 24, the output d' of the sexagesimal counter 2, and the output a' of the clock A to the AND circuit 17. , when the output c'5 of the OR circuit 24 is at H level, a clock e' without the 60nth pulse is obtained. Furthermore, when the output e''5 of the OR circuit 24 is inputted to the AND circuit 18 through the inverter 20, and a' and f' are used as the other two inputs and an AND is taken, the output of the OR circuit 24 becomes L level. When (60
A clock g' without the (n+1)th panorez is obtained. When e' and g' are input into the OR circuit 21, each time the line changes (every time the binary counter changes between H and L), e
' and g' appear alternately. This is used as a clock input for the 1-line memory 11, and the memory contents are output every clock. The subsequent steps are similar to the example shown in FIG. Therefore, θ is printed respectively.

In this case, since each missing pulse is shifted by one for each line, a printed image as shown in FIG. 2 is obtained as in the case of FIG. 3. I have explained to you how to eliminate white streaks and black streaks in a charged deflection type multi-jet plotter, but the white streaks and black streaks mentioned above are mainly caused by light clogging of the ink in the injection direction in a charged deflection type multi-jet printer. However, in cartridge scanning type quick jet printers, white stripes and black stripes occur due to errors in paper feeding accuracy. The present invention has been made with the object of eliminating the white streaks and black streaks in such a cartridge scanning type quick jet plotter. FIG. 7 is a diagram showing a quick jet plotter 1 to which the present invention is applied, in which 31 is a carriage, 32 is a printing head, and 3 is a printing head.
3 is a spiral shaft, 34 is a head feed motor,
By rotating the head feed motor 34 in the forward and reverse directions, the carriage 31 and hence the printing head 32 are reciprocated in the direction of arrow A.

The printing head 32 may be one having 10 to 30 nozzles of a pressure on-demand type, one having 10 to 30 nozzles of a charged binary deflection type, or a single type of charged multivalue deflection type nozzles. It may be of any kind, such as one having a nozzle. 35 is a recording medium, 36 is a platen, 37 is a recording medium holding roller, and 38 is a recording medium feed motor, which moves the recording medium 35 in the direction indicated by arrow B while the printing head 32 reciprocates once in the left and right direction. However, due to hunting, an error in detecting the position of the recording medium, etc., the recording medium shifts slightly in the feeding direction and stops, and if printing is performed in this state, the print will be the same as that of the previous carriage operation. The seams of the prints do not match up the next time the carriage is operated, resulting in white or black streaks.

The present invention was made in order to eliminate the white streaks and black streaks as shown above, and basically, as shown in FIG. a,...
and the top row of prints B2, b4, b6... at the next printing.
This is intended to improve image quality by overlapping the seams to make the seams less noticeable.

FIG. 9 is a diagram showing an embodiment of an electric circuit for carrying out the printing shown in FIG. 8, and is a diagram showing an example of printing 20 dots per head.

In FIG. 9, data signals are latched into a 1-line shift register 41 for each line (left and right columns in FIG. 8), and are latched into a 20-line shift register 42 in response to data CLK. This data CLK is passed through the OR circuit 43 to 2
Q of the decimal counter 44 is supplied to the decimal counter 44.
1 output voltage is set to 20n+1 (n is set to high level every integer data clock, and every other 1 line data CLK is invalidated (non-printed signal) through the inverter 46. On the other hand, the Q2O output of the 20-decimal counter 44 The voltage becomes high level every 20n data clocks, and the inverter 45
Through this, every other signal other than Q1 is invalidated. When data for 20 lines enters the 20-line shift register 42, the printing CLK is output and the carriage starts moving.
The 0 line shift register 42 outputs every 20 data to the switching circuit 47, and printing is performed based on this output signal.

When the carriage movement is completed and a line end signal is output, the contents of the 1-line shift register 41 remain unchanged, and only the previously invalidated data is transferred to the 20-line shift register 42, and the next printing is performed. As a result,
Printing as shown in FIG. 8 is performed, and the seams in the printed portions become less noticeable, and the overall image quality can be improved. Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.
For example, the recording medium is wound around a rotating drum, and the carriage is moved once in the direction of the rotating shaft while the rotating drum rotates multiple times.
It is easy to understand that the present invention can also be applied to a reciprocating spiral paper feeding system, and in that case, a signal for each rotation of the drum may be used instead of the line end signal shown in FIG. 9. It is also easy to understand that a multihead system can be applied to the spiral paper feeding system, and in that case, the circuit configuration shown in FIG. 3 or 4 can be used as is. As is clear from the above description, according to the present invention, the seam between the previous printing section and the next printing section is not noticeable, so that the overall image quality can be improved.

[Brief explanation of the drawing]

Figures 1A and B are diagrams showing conventionally printed images of a quick jet plotter, and Figures 2A and B are diagrams showing an example in which white lines and black lines in the printed image shown in Figure 1 have been eliminated. Figures 3 and 4 are electrical circuit diagrams for obtaining the printed image shown in Figure 2, respectively, and Figures 5 and 6 are electrical circuit diagrams for obtaining the printed image shown in Figures 3 and 4, respectively. Electric signal waveform diagram of each part,
FIG. 7 is a perspective view showing an example of a quick jet plotter to which the present invention is applied, FIG. 8 is a view showing an example of a printed image printed by the present invention, and FIG. 9 is a diagram showing an embodiment of an electric circuit for obtaining the printed image shown in FIG. 8; FIG. 1, 12... Clock generator, 2...
...sexagesimal counter, 3, 5, 8, 10, 15, 17
, 18...AND circuit, 4, 19...
Binary counter, 9, 21, 24...OR circuit,
7, 20, 22... Inverter, 11...
...1 line memory 13...Latch circuit,
14...Shift register, 16...Charged electrode array, 23...Delay circuit, 31...
...Carriage, 32...Printing head, 33
...Spiral shaft, 34...Head feed motor, 35...Recording medium, 36...
...Platen, 37...Recording medium holding roller, 38...Recording medium feed motor, 41...
...1 line shift register, 42...20 line shift register, 43...OR circuit, 44
......2decimal counter, 45, 46...
Inverter, 47...Switching circuit.

Claims (1)

[Claims] 1. A printing head having a plurality of nozzles arranged perpendicularly or obliquely to the scanning direction of the carriage, or an electric multilevel deflection type unit that deflects perpendicularly or obliquely to the scanning direction of the carriage. In an inkjet plotter in which a printing head with one nozzle is mounted on a carriage and the carriage is moved relative to a recording medium to perform printing, the bottom row of the print head at the previous printing in the feeding direction of the recording medium is used. An inkjet plotter characterized by having a selection circuit that causes at least one dot or more to overlap with the topmost printing portion of the next printing and selects an ink droplet to print the overlapping portion.