JPS5862064A - Ink jet printer - Google Patents

Abstract

PURPOSE:To make a record starting position always constant, by correcting the record starting position in response to the changing of the recording speed so as to obtain the same starting position. CONSTITUTION:Carriage position detecting sensors 31-34 are provided for shifting the print starting position in response to each scanning speed of the carriage 1. AND gate circuits 51-54 are provided for selecting output signals from said sensors and guide them to a print data controller 6. For example when capital letters are printed, the AND gate circuit 51 is selectively opened by the signal S1, and the output signal of the carriage position detecting sensor 31 is guided to the print data controller 6 and used as a record starting signal. When small letters are printed, the AND gate circuit 54 is selectively opened, and the output signal of the carriage position detecting sensor 34 is guided to the print data controller 6 and used as the record starting signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of an inkjet printer that is capable of switching recording speeds, and in particular, the present invention relates to an improvement in an inkjet printer that is capable of switching recording speeds. By making corrections and recording from the same position,
This is intended to improve the quality of recorded images.

Generally, in inkjet printing, ink droplets are ejected from a nozzle to record characters, etc. on recording paper.
At this time, it takes a certain amount of time for the ink droplets ejected from the nozzles to reach the recording paper surface. On the other hand, since serial printers generally record while scanning the carriage in the horizontal direction, the ink droplets ejected from the nozzle have kinetic energy in the horizontal direction (X-axis direction), as shown in Figure 1. Therefore, when the carriage reaches the recording paper, it reaches a position shifted from the position P that it would reach if the carriage was stopped, for example, a position P2O. This shift in the arrival point of the ink droplets becomes larger as the scanning speed of the carriage increases, but it does not become a problem as long as it does not change during recording on a single sheet of recording paper. However, when the constant scanning speed of the carriage changes within a sheet of recording paper - for example, when changing the character size by changing the scanning speed of the carriage,
The scanning speed is increased for uppercase letters and slower for lowercase letters, but if the carriage scanning speed is changed in this way, for example, as shown at t in Figure 2, the recording start position shifts and the recording becomes difficult to read. Become.

The present invention has been made in order to solve the above-mentioned drawbacks of the prior art, and in particular, an inkjet printer in which the recording start position is always constant regardless of the change in the recording speed. This is what we are trying to provide.

Figure 3 is a schematic configuration diagram of a normal inkjet printer. In the figure, 1 is a carriage, 2 is a recording paper, 3 is a carriage position (ink droplet ejection start position t) detection sensor, and as is well known, printing starts. In order to know the position, a carriage position detection sensor 3 is provided, and printing is started at the point where the carriage 1 passes the carriage position detection sensor 3. Therefore, in the above-mentioned inkjet printer, the scanning speed of the carriage is changed depending on the size of the printed character, as mentioned above, but when the scanning speed of the carriage is changed, the printing start position differs as mentioned above. , the recorded image quality will deteriorate. In order to make these printing start positions the same, it is sufficient to use the fastest printing speed as a reference and delay the printing start position of the slowest printing speed by taking into account the speed difference. For example, in FIG. 1, Let point 0 be the point where ink is ejected from the nozzle, Po be the point corresponding to the 0 point on the recording paper surface, P be the recording position when the carriage and spear are moving at speed v2, and now point 22. If you want to align the recording start position for both uppercase and lowercase letters, at speed v2 (when printing uppercase letters), it is sufficient to eject ink droplets at the 0 point, while at speed v1 (lowercase letters) During printing), if an ink droplet is ejected at position 0' shifted by the difference between P2 and P□, the ink droplet will reach point P2. That is, the first
If the ink droplet ejection points are shifted so as to become OO'-P1P2, the printing start position can be made the same regardless of the carriage scanning speed.

The present invention has been made based on the above-mentioned operating principle, and will be described in detail below with reference to the drawings.

FIG. 4 is a configuration diagram for explaining one embodiment of the present invention, in which 1 is a carriage, 2 is a recording paper, 31.3□, 3
3.34 is carriage position detection sensor, 41.42
．． 4. j, 44 are amplifiers, 5□, 5□, 53.
54 is an AND gate circuit, 6 is a print data controller, and as shown in the figure, carriage position detection sensors 31 to 34 are provided to shift the print start position corresponding to each scanning speed of the carriage 1. (in the illustrated example, it is assumed to be 4 speed), and includes AND gate circuits 51 to 54 for selecting output signals from these sensors and guiding them to the print data controller 6,
For example, when printing uppercase letters, the AND gate circuit 51
is selectively opened by the signal S□, and the output signal of the carriage position detection sensor 3□ is guided to the print data controller 6 to be used as a recording start signal. When printing lowercase letters, the AND gate circuit 54 is selectively opened by the signal S4. The output signal of the carriage position detection sensor 34 is guided to the print data controller 6 and used as a recording start signal.

In addition, for the printing between the above-mentioned uppercase letter printing and lowercase letter printing, the sensor 3□ or 33 and the AND gate circuit 5
It is easy to understand that the same method as described above can be carried out by using .degree. or .53.

FIG. 5 is a main part configuration diagram for explaining another embodiment of the present invention, in which 3 is a carriage position detection sensor, 4 is an amplification and waveform shaping circuit, 7 is a delay circuit, and an AND gate circuit. 5, to 54 are selectively opened by signals 81 to S4 corresponding to the size of the printed characters as in the previous embodiment, and the output signal from the sensor 3 is delayed by the delay circuit 7, as shown in FIG. Output signals 01 to 04 at the timing
Similarly to the previous embodiment, for example, when printing uppercase letters, the AND gate circuit 51 is opened and the output signal 0 is generated.
1 is used as the print start signal, and when printing lowercase letters, the AND gate circuit 54 is opened and the output signal is 0.
4 is used as the print start signal.

FIG. 7 is a block diagram of main parts for explaining still another embodiment of the present invention, and FIG. 8 is a flowchart for explaining its operation. In the figure, 8 is Ilo, 9 is μCPU, 10 is is ROM/RAM, 11 is a timer, 12 is Ilo, and when the print start signal is input to I108, μCP
U9 sets the carriage speed to the carriage drive motor driver and outputs a motor on (drive) signal. When the motor is driven and the carriage moves and the carriage passes the carriage position detection sensor (ink droplet ejection start position detection sensor) 3, μ
The CPU 9 sets a delay time in the timer 11 according to the designated speed with reference to the side of the .

The timer 11 operates in this manner, and after a specified delay time, the timer 11 interrupts the μCPU, and this interrupt causes the μCPU to output a synchronization signal and print data for outputting print data. do.

As is clear from the above description, according to the present invention, the printing start position remains constant regardless of the switching of the printing speed, so it is possible to eliminate irregularities in the printing start position on a single sheet of printing paper. Recorded image quality can be improved.

[Brief explanation of drawings]

Figure 1 is a diagram for explaining the operating principle of the present invention, Figure 2 is a diagram for explaining the operating principle of the present invention.
The figure shows the deviation of the printing start position, FIG. 3 is a main part configuration diagram showing an example of a conventional inkjet printer, and FIG.
6 is a time chart for explaining the operation of the circuit in FIG. 5, and FIG. 7 is a main part configuration diagram for explaining still another embodiment of the present invention. FIG. 8 is a flowchart for explaining the operation of the circuit shown in FIG. Carriage, 2...Recording paper, 3.3, ~34 - Carriage position (ink droplet ejection start position) detection sensor, 4.41~44...Amplifier, 51~54...AND gate circuit, 6... - Print data controller, 7...Delay circuit, 8-...Ilo, 9...μCPU. 10-ROM/RAM, 11-=timer, 12.
Ilo. Figure 1 Figure 2 Figure 3 Figure 12b2b+ Figure 6 Figure 7

Claims (1)

[Claims] An inkjet printer capable of switching recording speeds, characterized in that the recording start position is corrected to the same position in accordance with the switching of the recording speeds.