JP5600942B2 - Inspection method - Google Patents

Description

The present invention relates to a cap inspection method . In particular, the present invention relates to an inspection method for judging the quality of characters and figures printed on the surface of a plastic molded product having a space inside.

  A plastic molded product, for example, a cap of a plastic pen such as a ballpoint pen, is printed with characters and figures for representing the name of the manufacturer and sales company and the properties of the pen. This printing is performed mechanically, automatically and continuously by a pad printing machine (also called a tampo printing machine). However, there may be a printing error such that the printed characters and graphics are not printed at a predetermined position, or are not printed clearly such as partly missing. Conventionally, humans have performed visual inspection using a magnifying glass or the like as a method for detecting such defective products.

  In addition, as a method of mechanically inspecting the print, the printed character or figure is illuminated with white light such as an incandescent bulb or a fluorescent lamp, and the image is recognized by the camera. There was a way to judge the product.

However, the former method, of course, causes a test error due to fatigue, and there is a problem that the inspection standard varies depending on the inspector.
Further, the latter method has a problem in inspection accuracy depending on the type of the target object. In particular, in the case of a white writing pen cap, there is a problem that white light is reflected by the cap and characters and figures cannot be recognized at all.

Japanese Patent No. 3274186

The present invention provides, firstly, an inspection method capable of solving problems that occur when a human visually observes, that is, the effects of fatigue and variations in inspection standards, and secondly, the inspection object is illuminated. To provide an inspection method capable of reliably recognizing printed characters and figures even in the case of an object that reflects light.

In order to solve the above problems, the inspection method according to the present invention, meet a method for inspecting a printing state of directly printed characters or graphics rather than on the outer surface label of the cap for a plastic writing having a space therein And an image recognition means for observing the characters or figures formed by light emitted from the illumination means toward the inner surface of the cap and the light emitted by the illumination means being transmitted through the cap , and an image of the image recognition means. It is characterized by comprising a controller that receives information and determines whether the print state of the character or graphic is good or bad.

Even if the cap strongly reflects illumination light such as white, the inspection method according to the present invention illuminates light from the inside of the cap , so that the transmitted light is used to recognize printed characters and figures. can do.

1 shows a schematic configuration of an apparatus for performing an inspection method according to the present invention. 1 shows a schematic configuration of an apparatus for performing an inspection method according to the present invention. The object of the inspection method concerning the present invention is shown.

Figure 1 is one embodiment of an inspection method according to the present invention, showing a schematic structure of an apparatus for the inspection method of a cap of plastic color ballpoint pen. The entire box-shaped illumination tube 10 is held by the support column 20. A camera 2 (model UL-1460SE-C-GL manufactured by Imaging Development System) is attached to the inner surface of the upper wall of the illumination tube 10 as image recognition means. The lower side facing the upper wall of the illumination tube 10 is open, and a stage 3 is provided on which a cap X of a plastic color ballpoint pen as an object is held and fixed. An LED as an illumination means is attached near the stage 3 of the support column 20. The LED illuminates the internal space of the object X. Specifically, when the object X is a ballpoint pen cap, light enters from the insertion hole of the cap. The camera 2 observes characters or figures formed by light transmitted from the inner surface of the object X toward the outside. Image information observed by the camera 2 is input to the controller 4. The controller 4 stores a reference pattern in advance, and compares the observed image information with the reference pattern. The illumination tube 10 may be provided with a light blocking member for preventing disturbance.

  FIG. 2 is a diagram illustrating a relationship between light emitted from an LED and a target object when a ballpoint pen cap is used as the target object X. For example, an LED that emits white light is used as the LED. When the positional relationship between the object X placed on the stage 3 and the LED is adjusted, the LED emits light based on a command signal from the controller 4. The emitted light of the LED travels into the internal space of the object X, diffuses and permeates through the inner surface of the object X, and exits outward. In the figure, the state of diffusing / transmitting at four locations is shown for the sake of convenience, but in practice, this is performed over the entire inner surface of the object X. Note that the LED is not limited to the white light emitting type, and may emit other colors of light.

The inspection method of the present invention is particularly effective when the object is a cap of a plastic color ballpoint pen that is white, particularly milky white. This is because, when the outer surface of the cap is illuminated with light, the reflected light is too strong and the camera cannot recognize characters or figures printed on the outer surface.

In the present invention, the emission intensity of the LED may be further changed in addition to the emission color of the LED depending on the type of the object. Furthermore, in addition to RGB, LEDs can be installed in combination with IR-LEDs and UV-LEDs.
Further, the installation position of the LED is not limited to the figure as long as the characters and figures to be inspected should be clearly observable, and the position can be adjusted according to the inspection object.
However, in the case of a cap for a writing pen, since the overall count is a substantially cylindrical body and characters and figures are printed on the curved outer surface, as shown in FIG. It is preferable to illuminate oppositely. In addition, when the hole is formed also in the front-end | tip of a cap, you may make light inject from the said front-end | tip.
Moreover, it is desirable that the apparatus for performing the inspection method of the present invention is mounted on a tampo printing machine. This is because the printing state can be observed while continuously printing with a tamp printer.

  FIG. 3 schematically shows an inspection object according to the present invention. The object is a plastic ballpoint pen cap, and the letters “ABC” are printed on the outer surface. When illuminated from the inside of the cap as in the present invention, the camera can correctly recognize the characters “ABC”.

2 Camera 3 Stage 4 Controller 10 Lighting tube 20 Prop

Claims (1)

A method for inspecting the printed state of characters or figures printed directly on the outer surface of a plastic writing cap having a space inside, not a label,
Light emitted by the illumination means toward the inner surface of this cap ,
The character or figure formed by transmitting the light emitted from the illumination means through the cap is observed by the image recognition means,
The receiving image information of the image recognition means the quality of the printing state of the character or graphics is determined by controller,
Inspection method characterized by that.

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