JPS58183265A - Checking system for operation of ink jet head - Google Patents

Abstract

PURPOSE:To obtain an effect on the maintenance of the performance of a printing apparatus when it is operated again from the state of stoppage for a long time and when a jetting function is stopped, by detecting an optical change due to ink by detecting means so as to check the operation of an ink jet head. CONSTITUTION:A testing member 7-1 moves an ink jet head unit 1 outside an area wherein printing is effective, moving, for instance, a head 1-1 to a position opposite to a sprocket hole 2-1 of a printing paper sheet 2 and making it perform jetting. Ink particles pass the sprocket hole 2-1 and a hole 4-1 of a paper sheet guide 4 and reach a detecting means 3, coloring a transparent film 3-1. An optical detection element 3-4 detects this coloring and a signal thereof is input in an operation checking circuit 6. Meanwhile, a signal making the head 1-1 operate is also input in the circuit 6. The circuit 6 delivers a signal informing that jetting is checked. Recognizing this signal, a printing execution member 7-2 restores the head unit 1 to the state of starting printing and makes it perform printing. If the circuit 6 delivers an abnormality signal, an inverter 7-4 operates to make the testing member 7-1 operate again for checking. When the test jetting is repeated in the prescribed number of times, an alarm is issued.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Public Funding of the Invention The present invention relates to a method for checking the operation of an inkjet head of a printing apparatus equipped with an inkjet head.

(b) Background of the technology A mark 111IIlf! is equipped with an inkjet head as a device for outputting data processed by a computer, especially graphic information. The place is mown. This printing device records predetermined information or figures using ink droplets ejected from the inkjet head by moving the inkjet/t\rad along the X-axis and moving the printing paper in the Y-axis direction. It looks like this.

(C) Prior art and problems The inkjet head has an internal ink reservoir and is structured to eject this ink from a thin nozzle.On the other hand, the ink used for convenience is designed to prevent printed characters or figures from becoming smeared. Quick-drying products are used for this purpose. This may cause problems when restarting the printing device, or if an abnormal condition occurs such as air bubbles suddenly appearing in the ink pipe in the inkjet head during printing and ink jetting stops, certain information or graphics may be lost. The disadvantage is that it cannot be obtained.

For this reason, it has been desired to check the operation of the inkjet head in case of abnormal conditions or during operation.

(d) Purpose of the Invention It is an object of the present invention to provide an inkjet head operation confirmation method for checking the operation of an inkjet head from the conventional situation as described above.

(e) Structure of the Invention Briefly stated, this invention provides a detection means at a position corresponding to outside the effective printing area of the attached printing paper, and moves the inkjet head outside the effective printing area indicated by -U when a suspicion arises. Then, the detection means corresponding to this movement position is made to eject ink, and the detection means detects an optical change due to this ink, thereby confirming the operation of the inkjet head.

G) Embodiments of the Invention A Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Fig. 111 is a block diagram of essential parts showing an embodiment of the 41I11 method of operation of an inkjet head according to the present invention, Fig. 111 is a schematic diagram of an embodiment of the detection means according to the present invention, and Fig. 48 is a schematic diagram of an embodiment of the detection means according to the present invention. FIG. In the figure, 1 is an inkjet head, 2 is a printing paper, 8 is a detection means, 4
5 is a paper guide, 5 is an amplifier, 6 is an operation check circuit, 7 is a control section, 8 is an OR circuit, and 9-1 to 9-n are injection control circuits.

The printing paper 2 is skipped line by line in the direction of the arrow in the figure by sprockets (not shown). Control s7 EHII
In execution 11-2, the inkjet head unit 1 is
After moving, for example, the required inkjet head 1-1 to a predetermined position in the X-axis direction in the figure and stopping, the jetting control circuit 9-1 is activated via the OR circuit 8 to move the inkjet head 1-1 to a desired position. Printing is performed on the printing paper 2 by ejecting ink. The test section 7-1 also performs the operation with the print execution section, but this test section 7-1 moves the inkjet head 1 out of the effective printing area, for example, as shown in FIG. It is configured so that it is moved to a position facing the sprocket hole 2-1 of the printing paper 2 and then ejected at that position as described above.

The ejected ink droplets pass through the sprocket hole 2-1 and the hole 4=1 provided in the paper guide 4, and reach the detection hand IR8. The detection means 8 is composed of a transparent film 8-1, a filter 8-2, a condensing lens 8-8, and a light detection element 8-4 stored in a cassette, as shown in the mg diagram, and detects the ejected ink. The grains color the transparent film 8-1. The photodetecting element 8-4 detects this coloring.

The transparent film 8-1 inside the Naori set container is in the test section 7-
Required inkjet head 1-1 to l by 1
A step feed is performed each time 11 is moved to the position of sprocket hole 2-1 to avoid overlapping with the previous test jetted ink drop.

The signal detected by the photodetector element 8-4 is amplified by the amplifier W6 and input to the operation confirmation circuit 6. On the other hand, the signal B that activated the inkjet head 1-1 is also input to the operation confirmation circuit 6. When the signals A and B are both input manually, the operation confirmation circuit 6 confirms that the desired inkjet head has ejected, and outputs, for example, a signal 11' indicating that the inkjet head has ejected normally. The print execution filr'l-2 that recognized '1# changes the inkjet printer to the printing start state.
Return the head unit l and execute printing. Operation confirmation circuit 6
When the outputs an abnormal signal ``0'', the inverter 7-4 operates to increment the counter 7-8, activates the test 57-1 again, and performs a recheck, and by repeating this, the number of test injections in 1 reaches the predetermined number of times. When this happens, the counter 7-8 issues an alarm.

The above-mentioned operation check is not only to check the presence or absence of ink droplets, that is, the presence or absence of jetting, but also to check if the speed of the jetted ink droplets is slow, the ink droplets will move away from the focal position of the condensing lens 8-8 and will appear on the transparent film 8-1. The velocity of this ejected ink drop can also be monitored since it goes undetected. Although the above explanation used the sprocket hole, it is of course possible to use any sprocket hole as long as it is outside the effective printing area.Furthermore, only the inkjet head 1-1 was explained, but the remaining It goes without saying that a plurality of heads l-2 to ln are also tested. Figure ＠a is a diagram showing another embodiment of the composition means of the present invention, and the difference from the previous embodiment is that a solution is placed in a transparent container, ink droplets are jetted into this solution, and changes in transparency are observed using light. The presence or absence of ink droplets is detected by a sensor, or the ink droplets are detected by analyzing the wavelength of light from an optical sensor and detecting a change in color. This embodiment also has the advantage that the inkjet head can eject ink to the same location as long as it is outside the effective printing area.

(g) Effects of the Invention As described above, according to the present invention, it is possible to check the operation of the inkjet head, and in particular, it is possible to check the operation of the inkjet head when the inkjet head is stopped for a long time, or when the jetting function suddenly stops during normal printing operation. This is highly effective in maintaining the performance of the printing device when it is stopped or the like.

! 4. Brief Description of the Drawings A. Figure H1 is a block diagram of essential parts showing an embodiment of the operation #Im type of the inkjet head according to the present invention. Figure 2 is a schematic diagram of an embodiment of the detection means according to the present invention. , FIG. 8 is a schematic diagram of another embodiment of the detection means according to the present invention.

In the figure, l indicates an inkjet head, 2 indicates printing paper, and 8 indicates a detection means.

Claims (1)

[Claims] In a printing device that performs printing using an inkjet head, a detection means is provided at a corresponding position outside the effective printing area of the attached printing paper, and the inkjet head is activated when necessary.
After moving the head out of the effective printing area, ink is ejected to the detecting means corresponding to this moving position, and the detecting means detects optical facilitation caused by the ink to confirm the operation of the inkjet head. An inkjet head operation confirmation method characterized by: