JPS61263760A - Ink jet printer - Google Patents

Abstract

PURPOSE:To enable two or more electrostrictive elements to be driven by a same drive circuit to reduce the required number of the drivers, by shifting nozzle pitchs between the respective colors little by little to shift the timing of driving the nozzle. CONSTITUTION:A plurality of nozzles 3 divided into (l) blocks, when nozzles of (m) number adjacent with each other are defined as one block, are aligned at angle theta to the direction in which the nozzles 3 move. When the pitch PN of the nozzle 3 has the horizontal component PNX and the vertical component PNNY and the dot to be printed has the horizontal component Px and the vertical component Py, they are so set as to meet the relations of PNX=nPx and PNy=Py. When the number (m) of the nozzles 3 is set 2, the vertical pitch Py has a relation Py=nPx tantheta between the nozzles for the same color, and Py=(n+1/4)Px tantheta between the nozzles for different colors, which induces discrepancy. But, this discrepancy reduces to a nearly inconsiderable amount by a method wherein; the large value is set for (n), results in theta of a small value, i.e., tantheta of a small value. It is needless to say that the value (n+p/l)Px can be applied to the vertical component in the pitch between different colors. (l, P are integers)

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an on-demand inkjet printer.

4 and 5 show the print head constituting the on-demand inkjet printer of the present invention. Grooves constituting the plurality of nozzles 3, the first ink chamber 4, the second ink chamber 5, etc. are etched, etc. A substrate 1 formed by the means of
A thin plate 2 is attached to the top surface of the . Ink chamber 4.5
! Electrostrictive elements 6, 7 are attached to the upper surface of the thin plate 2 corresponding to /c, respectively, with adhesive or the like. The above-mentioned substrate 1 to electrostrictive element 6.7 are integrated to constitute a print head 8, and the print head 8 is mounted on a carriage (not shown) at an angle θ with respect to the horizontal direction, as shown in FIG. It will be placed.

FIG. 6 shows the relationship between the arrangement specifications of the nozzles 3 and printed pixels, and a plurality of nozzles 3 are arranged in a line at an angle θ with the direction in which the nozzles 3 move. The pitch of the nozzles 3 is P. Let the horizontal component of P be P, the vertical component be 9, the horizontal component of the printed pixel be PI, and the vertical component be P. ing.

When performing color printing using such a print head 8, ink of the same color is supplied to each of the m nozzles 3 among the plurality of nozzles 3. Figure 6 shows the case where m = 2, and there are eight nozzles 3 in total, two each from the top, yellow (to), magenta, M1, cyan (
C), black (BK) ink is supplied. Therefore, in order for the ink particles ejected from each nozzle 3 to align vertically to form a pixel, if the horizontal traveling speed of the nozzle 3 is V, the adjacent nozzles 3 must be Py
It is driven with a timing shift that is an integral multiple of I. In addition, in this method, in order to increase the frequency of ink particle generation and stabilize the generation, as shown in FIG.
It is necessary to drive the electrostrictive elements 6.7 of the second ink chamber 5 and the second ink chamber 5 with pulses having different timings.
One drive circuit is connected to each of the terminals 7 and 7.

Therefore, if the number of nozzles is increased in an attempt to improve the printing speed, twice the number of drive circuits as the number of nozzles will be required, resulting in an increase in the cost of the device.

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and provide an inexpensive inkjet printer.

In the present invention, when the nozzle pitch of a print head installed at an angle is set large, the horizontal component of the nozzle pitch becomes sufficiently larger than the vertical component, and the horizontal pitch shift of the printed pixels becomes the vertical pitch shift. Focusing on the fact that it does not have a large effect, the nozzle pitch and drive pulse timing were devised so that the number of drive circuits did not increase in proportion to the number of nozzles.

An embodiment of the present invention is shown in FIGS. 1 and 2 for the case where m=2. The horizontal component of the pitch between the nozzles 3 of the same color is %nPII%, and that between the nozzles 3 of different colors is (n+±)P8. Further, the electrostrictive element 7 in the second ink chamber 5 is connected to a Y driver 11 for each color. M driver 12, C driver 13,
The electrostrictive elements 6 of the first ink chamber 4 are connected to each drive circuit of the BK driver 14, and are grouped in order of each color.
It is connected to the drive circuit of the nozzle driver 15 and *2 nozzle driver 16. Each driving circuit is connected to a pulse generating circuit 18 that receives a signal from a reference clock/generating circuit 17 and generates a pulse for each color.

When attempting to print with such a configuration, the printing timing of each nozzle 3 to align the pixels in the vertical direction is as follows for the #1 nozzle of Y, assuming the horizontal speed of the nozzle 3 is V: Y #2 nozzle is npv/.

p M #1 nozzle is % + (n-)+) P5/
v= (2n-)-t) P$M $2 # (
2n-)-))PyI+"P, 4=(3n-)-))P
, (vC reference (3n→
-)) %+(n-)+)'=(4n zozo, CO2$ (4n+4zo each + nPyV=(5n+
2) P5/v BK *1 Small (5n+/)'/v+(”
++)”'v=(6n+s/4)P5/.

BK m2” (6”+s/4) Pk +
It is necessary to drive with a delay of nP7y''(7''+J/4)'8.

Therefore, as shown in the timing chart of Figure 3,
With respect to the P5/I timing pulse generated by the reference clock generation circuit 17, the Y driver 1 has the same phase, the M driver 2 has a ten-phase delay, the C driver 3 has a one-phase delay, and the BK driver 14 has the following: By driving with a % phase delay and further driving the #1 nozzle driver 15 with the phase of each color, ink is ejected from each nozzle 3 at the same position in the vertical direction (the same applies to the 42 nozzle driver 6).
According to this method, the vertical pitch P between nozzles of the same color becomes
is small, that is, tanθ is small and can be almost ignored.

In addition, in this example, the horizontal component of the pitch between different colors is (
n++)P, but (n + t) P-(/
, P integer).

According to the present invention, since the nozzle pitch between each color is slightly shifted and the timing of driving the nozzles is shifted, several electrostrictive elements can be driven by the same drive circuit.

Therefore, for a print head with one color and m nozzles each, the number of drivers required is 21! From m pieces (t-1-
m).

[Brief explanation of drawings]

Figures 1 to 3 show one embodiment of the present invention.
The figure is a block diagram showing the drive circuit, Figure 2 is a side view of the print head seen from the front, Figure 3 is a time chart for explaining the operation, and Figures 4 and 5 show the schematic configuration of a conventional print head. A plan view and a side view, FIG. 6 is an explanatory side view showing the relationship between the print head and printed pixels, and FIG. 7 is a time chart for explaining the operation of the print head shown in FIG. 4. In the figure, 1 is a substrate, 2 is a thin plate, 3 is a nozzle, 4 is a first ink chamber, 5 is an f42 ink chamber, 6.7 is an electrostrictive element,
8 print heads, 11 to 16 are drivers, 17 is a reference clock generation circuit, and 18 is a pulse generation circuit. Name of patent applicant Hitachi Koki Co., Ltd.>Figure 3

Claims (1)

[Claims] 1. An on-demand inkjet printer that has a plurality of nozzles arranged in a straight line and prints by reciprocating in the horizontal direction, wherein m adjacent nozzles are considered as one block, Divided into l blocks, the horizontal component of the pitch between m nozzles is n times the horizontal pixel pitch of the pixels to be printed, the pitch between blocks is (n+P/l) times, and the nozzle An inkjet printer (m, l, n
, P is an integer). 2. The ink chamber connected to each nozzle is divided into two, and an electrostrictive element is provided corresponding to each ink chamber, and inks of different colors are supplied to every m adjacent nozzles and ink chambers, The electrostrictive elements on the nozzle side of each block are connected to one of the l/m drivers in units of l/m, and the electrostrictive elements on the anti-nozzle side of each block are connected to one of the l drivers. An inkjet printer according to claim 1, wherein the inkjet printer is connected to an inkjet printer.