JPH0371851A - Ink jet printer - Google Patents

Abstract

PURPOSE:To prevent ink from dripping from an ink jet head during standby time by providing a constitution in which an ink jet head is freely rotated to a printing position where a nozzle is turned downward against a platen or a standby position where the nozzle is directed in an almost horizontal direction. CONSTITUTION:An ink jet head 20 mounted at an appropriate position above a platen in such a manner that it rotates and freely slides in a horizontal direction due to a shaft 21, is driven to rotate at a printing position where a nozzle 22 for ink ejection is directed in a vertical downward direction against the platen 6 or at a standby position where the nozzle 22 rotates at almost 90 deg. above the printing position and then is set in an almost horizontal direction. This rotation of the ink jet head is performed by a head rotation motor 23 through a gear 24. When in the printing mode, the nozzle 22 of the ink jet head 20 is directed downward to perform printing. In the meantime, when in the non-printing mode, ink is prevented from accumulating in the nozzle section by driving the head 20 to rotate to the standby position with the nozzle 22 set in an almost horizontal direction.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to improvements in inkjet printers using inkjet heads.

(b) Prior Art In the above inkjet printer, considering the influence of gravitation on ink ejection, for example, Japanese Patent Laid-Open No. 1-11325
It is preferable to install the head with the head facing downward as shown in the publication, but in this case, ink accumulates in the jet nozzle of the head during non-printing and becomes an obstacle to ink jetting during printing.
Furthermore, if this ink pool increases, there are problems such as ink dripping and staining the paper.

(c) Problems to be Solved by the Invention The present invention aims at preventing ink dripping from an inkjet head during standby such as during non-printing.

(d) Means for Solving the Problems The present invention provides a device in which a platen is arranged approximately horizontally and an inkjet head is mounted above the platen, with the nozzle of the inkjet head facing downward and facing the platen. It is configured to be rotatable between a printing position and a standby position where the nozzle is oriented in a substantially horizontal direction.

(E) Operation When printing, the inkjet head prints with its nozzle facing downward, while when not printing, the inkjet head is rotated to a standby position with its nozzle facing approximately horizontally. Prevents ink from accumulating in the nozzle part, etc.

(F) Example An example of the present invention will first be explained based on FIGS. 1 and 2. (1) is the printer main body, and the opening (2) of the lower case (3) with the upper surface opened (2) In the section, paper feed tray <4>
, paper guide (5), platen (6), paper ejection guide (7)
are arranged in sequence, and an automatic paper feed roller shaft (8> is installed on the paper guide (5> side) of the paper feed tray (4>).
In addition, a pair of upper and lower paper feed roller shafts (9) (9) are provided on the paper guide (5) side and the paper ejection tray (7> side of the platen (6), respectively).
), paper ejection roller shafts (10) (10) are installed, and a plurality of automatic paper feeding rollers (11) (11) are attached to these roller shafts, respectively.
) (11), paper feed roller (L2) (12><12), and paper ejection roller (13) (13) (13) are installed.

(14> is an upper case that is attached to the opening (2) of the lower case (3), and is a paper feed port located above the paper feed tray (4) and into which printing paper (15>) is inserted. (16) is open, and a viewing window (18) is located above the platen (6) and pivotally supports a cover (17) so as to be openable and closable, and is opened and closed by the cover; Further, a paper discharge port (19) is formed at the lower end of the rear surface.

(20) is an inkjet head mounted on a shaft (21) at a suitable position above the platen (6) so as to be able to rotate and slide in the horizontal direction, and a nozzle for ejecting ink.
22) facing the platen (6>) facing downward vertically, and approximately 90 mm above this printing position.
The head rotation motor (23) rotates the nozzle (22) to a standby position (position indicated by a broken line in the figure) to turn the nozzle (22) in a substantially horizontal direction via a gear (24). be done.

(25) is a kick ridge motor that moves the inkjet head (20) in the width direction of the printing paper (15), and is driven by a pair of pulleys (26) (26) and a driving member (27) such as a wire or belt. Inkjet head (20
>Move.

(28) is a paper feed motor that rotates the paper feed roller shaft (9) through gears (29) and (29), and also connects this roller shaft and the paper ejection roller shaft (10> with a belt (30). >, and the roller shafts (9) and (10) are interlocked with this belt.

(31) is the automatic paper feeding motor, gear (32) (32
) to rotate the automatic paper feed roller shaft (8).

(33) controls the rotation of the head rotation motor (23), the Kikeridge motor (25), the paper feed motor (28>, the automatic paper feed motor (31), etc.), and also controls the rotation of the inkjet head (20). For example, as shown in FIG. 3, when the power is turned off (Sl) by turning off a power switch (not shown), the control circuit sends control signals to the inkjet head (20
The home position sensor (34) installed at the home position of the inkjet head (20) is used to detect whether or not the inkjet head (20) is at the home position (S2). 20> to the home position (S3), then detect whether the carriage sensor (35) is ON or not (S4). If it is OFF, operate the head rotation motor (23) until it turns ON (S4). 55), the inkjet head (20> is rotated approximately 90 degrees from the printing position to the standby position, and the carriage sensor (35>) is turned ON.
Then, the power supply to the head rotation motor (23) is stopped (56).

In the above embodiment, explanation will be given regarding the time of turning off the power, but for example, the inkjet head (20) may also be controlled to rotate to the standby position even when no printing operation is performed for a predetermined period of time. ) can prevent ink from accumulating in the area.

Further, in the above embodiment, the inkjet head <20> is rotated above the platen (6) when it is on standby.
For example, as shown in Figures 4 and 5, the platen (6)
A storage opening (36> is provided opposite to the home position position of the inkjet head (20) of
It may be rotated approximately 90° downward and stored below the platen (6), thereby making it possible to reduce the height dimension of the Bunonta main body (1).

(G) Effects of the Invention With the configuration of the present invention, by directing the nozzle of the inkjet head downward during printing, the influence of the gravitational force of ink droplets ejected from the nozzle is prevented, and high-quality printing is achieved. At the same time, when the inkjet head is on standby when printing is not performed for a relatively long time, the inkjet head can be
By rotating the nozzle to a substantially horizontal position, it is possible to reliably prevent nozzle clogging due to ink accumulation in the nozzle portion and ink dripping onto the printing paper.

[Brief explanation of drawings]

FIG. 1 is a side longitudinal cross-sectional view of the present invention, FIG. 2 is a plan view, FIG. 3 is a broached yard diagram for explaining the operation, and FIG.
The figure is a longitudinal sectional view showing another embodiment, and FIG. 5 is a plan view showing another embodiment. (6)... platen, (20)... inkjet head, (22)... nozzle, (33)... control circuit.

Claims (3)

[Claims] (1) In a device in which the platen is arranged approximately horizontally and an inkjet head is mounted above the platen, the inkjet head is placed at a printing position with the nozzle facing downward facing the platen, and the nozzle is placed approximately horizontally. An inkjet printer characterized in that it is configured to be rotatable between a standby position and a standby position. (2) The inkjet printer according to claim 1, further comprising a driving means for rotationally driving the inkjet head to the standby position when not printing and when the power is turned off. (3) The inkjet printer according to claim 1, wherein the inkjet head is rotated approximately 90 degrees below the platen during standby.