JPS626994B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording apparatus having a plurality of deflecting means and capable of feeding paper at a constant speed to increase the speed.

2. Description of the Related Art Conventionally, inkjet recording apparatuses in which a large number of heads are arranged and dots are filled by deflecting the distance between the heads are well known. When printing one line using such a recording device, such as a printer, there is a margin between the characters, so
When collecting unnecessary ink droplets, the shape and precision of the gutter are not required so much. However, Copia,
When attempting to perform full-scale printing across rows and rows, such as with fax, a strict gutter shape and precision are required. Therefore, if a large number of heads are arranged, the device becomes expensive. On the other hand, if the conditions for gutter shape and accuracy are relaxed, the amount of deflection from the gutter level to the first stage must be increased.
It becomes difficult to maintain deflection accuracy.

Therefore, a first deflection means consisting of a vertical deflection electrode and a horizontal deflection electrode, and a second deflection means consisting only of a vertical deflection electrode are provided, and the vertical deflection component of the first deflection means is controlled by the second deflection means. An inkjet recording apparatus has been proposed in which the polarization is canceled so that only the horizontal deflection component remains. In such an inkjet recording device, the charged ink droplets used for printing are printed on the recording paper by the second deflection means, with the vertical deflection component of the first deflection means canceled, On the other hand, uncharged unnecessary ink droplets travel straight and are captured by an unnecessary ink drop collecting gutter provided behind the first deflection means. Therefore, the gutter that collects unnecessary ink droplets only needs to be placed at a vertical level that can capture the unnecessary ink droplets, and there is no need to place the gutter between each head, so the conditions for shape and accuracy are relaxed. This will help standardize the gutter. Then, the missing dots between the heads can be filled by deflection, making it possible to print on the entire surface one row and one column laterally, and it is also easy to maintain deflection accuracy.

In such an inkjet recording device, when one line of printing is completed, the recording paper is
The step is sent and the next line is printed. As described above, in the recording apparatuses proposed so far, the recording paper is not moved until the printing of one line is completed, which is extremely disadvantageous in increasing the speed. Therefore, it is possible to increase the speed by feeding the paper at a constant speed, but in this case, while each head is filling the dots by deflection,
Since the paper is moving, the dots are misaligned in the paper feeding direction, and the dots are no longer lined up horizontally on one line.

The present invention aims to eliminate such drawbacks, and has a plurality of deflection means, so that even when paper is fed at a constant speed, the dots are not shifted in the paper feeding direction, and the dots are placed on one line. DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, with the aim of providing an inkjet recording apparatus in which inkjet recording apparatuses are arranged in a manner similar to that of the present invention.

FIG. 1 is a diagram showing the overall configuration of an embodiment of the present invention, in which 1 is a head, 2 is a charging electrode, 3 is a detection electrode,
Reference numeral 4 indicates a vertical deflection electrode of the first deflection means, and reference numeral 5 indicates a horizontal deflection electrode.The vertical deflection electrode 4 and the horizontal deflection electrode 5 are used in common to form a single (pair of) electrodes, and this single electrode may be arranged at an angle to the vertical and horizontal deflection planes to obtain vertical and horizontal deflections. 6 is a gutter for collecting unnecessary ink droplets, 7 is a vertical deflection electrode of the second deflection means, 8 is a high voltage constant voltage power source that supplies voltage to the vertical deflection electrode 4, and 9 is a constant voltage supply that supplies voltage to the vertical deflection electrode 7. A voltage power source and 10 are recording sheets that are fed at a constant speed.

To explain the operation of the apparatus shown in FIG. 1, ink droplets ejected from a head 1 are charged by a charging electrode 2, and the amount of charge is detected by a detection electrode 3. The charged ink droplets are then transferred to a vertical deflection electrode 4 and a horizontal deflection electrode 5.
The recording paper 1 is deflected by the first deflection means consisting of the vertical deflection electrode 7, and deflected by the second deflection means consisting of the vertical deflection electrode 7 in the opposite direction to the deflection by the vertical deflection electrode 4.
0 (dotted line A). Further, unnecessary ink droplets that are not electrically charged are not deflected by the first deflecting means and travel straight and are captured by the gutter 6 (dotted line b). Now, let E ₁ and E ₂ be the strength of the electric field in the vertical direction generated by the deflection electrode 4 and the deflection electrode 7, and let x _dy1 and x _dy2 be the respective vertical deflection amounts, then x _dy1 = KQ _j E ₁ ...(1) x _dy2 = KQ _j E ₂ ...(2) However, Q _j : Charge amount of the ink droplet at the time of deflection of the jth stage K: Expressed as a constant.

Now, if 60 heads are lined up in a 300 mm space, the horizontal deflection area of each head is 5 mm, and if printing is performed at a dot density D = 8 dots/mm, each head has a horizontal deflection area of 5 mm. The number of deflection stages is
There are 40 steps. Conventionally, to obtain this 40-stage deflection
A charging voltage is applied to the charging electrode in 5V steps with 100V as the first stage to control Q _j .

Now, assuming that the maximum deflection distance in the horizontal direction is x _dx , the voltages supplied to the vertical and horizontal electrodes are V _dy and V _dx , and the shapes of both electrodes are the same, then for 40 stages of horizontal deflection, exactly 1 Since the paper is fed by a dot (1/D), the deviation in the Y direction can be compensated for by making sure that x _dx V _dy /V _dx = 1/D (3) holds true. Note that since V _dy /V _dx represents the ratio of the vertical deflection distance to the horizontal deflection distance, 1/D represents the maximum vertical deflection amount, which is the paper feed amount at that time.

Therefore, we determined the amount of charge on the ink droplet at the 40th level in the horizontal direction.
If Q ₄₀ , from formulas (1) and (2), D = 8dots/mm, x _dy1 - x _dy2 = KQ ₄₀ (E ₁ - E ₂ ) = 1/8 ...(4) is satisfied. Setting E ₁ and E ₂ eliminates dot misalignment in the paper feeding direction that occurs due to constant speed paper feeding. However, if the voltages supplied to the deflection electrodes 4 and 7 are V _d1 and V _d2 , respectively, then E ₁ = kV _d1 ...(5) E ₂ = kV _d2 ...(6) (k: constant) Therefore, equation (4) is x _dy1 −x _dy2 =K′Q ₄₀ (V _d1 −V _d2 )=1/8……(7
) (K′=Kk: constant). Therefore, by providing a difference between the voltages applied to the deflection electrodes 4 and 7 so as to satisfy equation (7), it is possible to compensate for dot misalignment caused by constant speed paper feeding. Now, to obtain a deflection amount of 1/8 mm in the vertical direction, set V _d1 = 4.8 kV and (K'Q ₄₀
= 1/1600), V _d2 = 4.6 kV.

FIG. 2 shows another embodiment according to the present invention, in which a single high-voltage constant voltage power supply is used, 11 is a high-voltage constant voltage power supply, 12 is a first vertical deflection electrode (horizontal deflection electrode is not shown), 13 are the second deflection electrodes, 14, 15
is a resistor, and all other parts of the recording device are omitted. In this embodiment, the voltage applied to the second deflection electrode is divided by R ₁ and R ₂ , and in order to obtain the voltage ratio of V _d1 and V _d2 as in the embodiment of FIG. For example, R
= 230 kΩ, R ₂ = 10 kΩ. Note that R ₂ may be a fixed resistor, but by using a variable resistor of 15 kΩ, errors due to component variations or assembly variations in the first deflection electrode and second deflection electrode, errors due to paper feed speed deviations, and paper feed errors can be reduced. Errors due to speed deviation can be eliminated by adjustment, and dot misalignment can be eliminated with higher accuracy.

As described above, according to the present invention, a difference is created between the voltages applied to the vertical electrodes supplied to the first deflection means and the second deflection means, thereby compensating for the deviation caused by the relative movement of the head unit and the recording paper. be able to.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of one embodiment of an inkjet recording apparatus according to the present invention, and FIG. 2 is a diagram showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Head, 2... Charge electrode, 3... Detection electrode, 4, 12... First vertical deflection electrode, 7, 13...
...Second vertical deflection electrode, 5...Horizontal deflection electrode, 6...
...Gutter, 8, 9...High voltage constant voltage power supply.

Claims (1)

[Claims] 1. Ink jet head, ink droplet charging electrode,
a first deflecting the charged ink droplets vertically and horizontally;
a gutter for receiving uncharged ink droplets not deflected by the first deflection means, a second deflection means for providing a deflection in an opposite direction to the vertical deflection of the first deflection means; An image is generated between the vertical deflection voltage of the first deflection means and the vertical deflection voltage of the second deflection means, which has a polarity opposite to this deflection voltage, due to the relative movement of the ink jet head and the recording paper in the vertical direction. An inkjet recording device characterized in that a difference is provided to compensate for dot misalignment. 2. The inkjet recording apparatus according to claim 1, wherein at least one of the vertical deflection voltages is variable.