JP2001071507A - Charge control type ink jet printer and image printing position indicating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charge control type ink jet printer wherein a printing position (a height of printing) can be visually recognized and an optimum printing condition can be set in a short time. SOLUTION: A visible laser light from a laser light source 11 in a print head 1 is emitted to a diffraction optical element 12 and then a reference pattern B indicative of a printing region is projected to an object A to be printed. A mask member 13 for blocking a projection pattern from the diffraction optical element 12 to the object A is provided. The projection pattern has an angle greater than a deflection angle θ (a spreading angle) of ink particles. The deflection angle θ (the spreading angle) of ink particles is equal to a spreading angle of the projection pattern from the diffraction optical element 12. As a result, even when a distance between the print head 1 and object A is varied, it is possible to visually recognize an accurate printing position (a height of printing) corresponding to the variation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge control type ink jet apparatus for selectively charging continuously ejected ink particles, deflecting the charged ink particles and hitting the object to be printed to perform a printing process. The present invention relates to a printer, and more particularly to a means for designating a printing position when performing the printing process.

[0002]

2. Description of the Related Art An ink jet printer is one type of printer that performs printing without applying pressure (printing pressure). In this ink jet printer, printing processing is performed by ejecting fine particles of ink from a nozzle and hitting the object to be printed to form a dot pattern. Depending on the ink particle control method, there are a charge control method and an on-demand method.

In the former type of charge control type ink-jet printer, the ink particles are continuously ejected from nozzles, and the ejected ink particles are selectively charged with a pulse potential and passed between deflection electrodes. Thus, the recording medium is deflected according to the charge amount and struck at a predetermined position on the object to be printed, and a dot pattern is formed on the object to be printed to perform the printing process. Unnecessary ink particles that are not charged are collected by a collector called gutter and reused.

In a company that manufactures foodstuffs in a mechanical industry,
Industrial inkjet printers are widely used to print information (such as date of manufacture, expiration date, product name, etc.) indicating the characteristics of food products on articles such as storage boxes, storage containers, storage bags, etc. of manufactured food products. It's being used. In such a case, it is general to continuously perform printing processing on the articles such as the storage box, the storage container, and the storage bag conveyed and moved by the belt conveyor. A charge control type ink jet printer adopting a control method is widely used.

[0005]

In such a charge control type ink jet printer, the deflection angle is controlled according to the magnitude of the charge amount of the ink particles, and when the charge amount is large, the deflection angle is increased. Therefore, the deflection angle is controlled by adjusting the charge amount. Further, since there is a deflection angle, the printing area fluctuates in accordance with the distance from the source (printer head) of the ink particles to the printing object. In other words, the longer the distance, the wider the distribution of ink particles on the printing object, that is, the larger the printing area.

In a conventional charge control type ink jet printer, there is no means for designating the printing position (printing height), and a number of times are performed while adjusting the distance between the printer head and the printing object. Also, a technique of performing a trial printing process and designating an appropriate printing position (printing height) is adopted. Therefore, it takes a long time to set the optimum printing conditions, and there is a problem that efficiency is low.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and allows the user to visually recognize the printing position (printing height) and set the optimum printing conditions in a short time. It is an object of the present invention to provide a charge control type ink jet printer and a printing position indicating device which are possible.

[0008]

According to a first aspect of the present invention, there is provided a charge control type ink jet printer which selectively charges continuously ejected ink particles, deflects the charged ink particles and strikes the object to be printed. In a charge control type ink jet printer that performs a printing process, a light source that emits visible coherent light, and a reference pattern for indicating a printing position is projected onto the object by irradiating the visible coherent light from the light source. And a diffractive optical element.

According to a second aspect of the present invention, there is provided a charge control type ink jet printer according to the first aspect, which blocks visible coherent light from the diffractive optical element to the object to be printed, the angle being larger than the deflection angle of the ink particles. It is characterized by further comprising means for performing.

According to a third aspect of the present invention, there is provided a charge control type ink jet printer according to the first or second aspect, wherein the reference pattern is a lattice pattern or a concentric pattern.

According to a fourth aspect of the present invention, there is provided a printing position indicating apparatus for selectively charging continuously ejected ink particles, deflecting the charged ink particles and hitting the object against an object to perform a printing process. When the device is configured to indicate a printing position on the object, a light source that emits visible coherent light, and the printing position on the object by irradiation of visible coherent light from the light source. A diffractive optical element for projecting a reference pattern for instructing.

According to a fifth aspect of the present invention, in the fourth aspect, the visible coherent light from the diffractive optical element to the object to be printed, which has an angle larger than the deflection angle of the ink particles, is blocked. It is characterized by further comprising means for performing.

According to a sixth aspect of the present invention, in the printing position indicating apparatus according to the fourth or fifth aspect, the reference pattern is a lattice pattern or a concentric pattern.

According to the charge control type ink jet printer of the present invention, an optical system having a light source for emitting visible coherent light and a diffractive optical element for projecting a reference pattern on an object to be printed by irradiation of visible coherent light. It has. Visible coherent light is emitted from the light source, and the emitted visible coherent light is irradiated on the diffractive optical element to project a reference pattern on the object to be printed. The printing position (printing height) is designated with reference to the projected reference pattern. Therefore, fine adjustment while repeating test printing as in the related art is not required, the printing position can be easily and accurately specified, and the optimum printing condition can be set in a short time. The visible coherent light is
A light having a wavelength that is perceived as light by the human eye and having a phase-aligned waveform that is kept sufficiently long spatially and temporally and has coherence. In the present invention, laser light is optimal.

Further, in the charge control type ink jet printer of the present invention, the deflection angle (spread angle) of the ink particles.
The light projection pattern from the diffractive optical element to the object to be printed having a larger angle is shielded. Therefore, the deflection angle (spread angle) of the ink particles and the spread angle of the light projection pattern from the diffractive optical element to the object to be printed become equal, and the printer head,
Even when the distance between the objects to be printed is changed, the light projection pattern also changes in accordance with the change, and the printing position (printing height) can always be accurately recognized.

The printing position indicating device of the present invention has a light source for visible coherent light and a diffractive optical element, and irradiates the visible coherent light from the light source to the diffractive optical element to print the object. A reference pattern is projected on an object. Therefore, it is possible to easily and accurately indicate the printing position on the printing object with reference to the projected reference pattern.

By using a lattice pattern or a concentric pattern as the reference pattern, the ease and accuracy of specifying the printing position is improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. FIG. 1 is a schematic diagram showing a configuration of a printer head of a charge control type ink jet printer of the present invention. In FIG.
A printer head 1 of a charge control type ink jet printer that performs a printing process in a non-contact manner with respect to the printing object A is provided at an appropriate distance above the printing object A.

The printer head 1 has an ejection nozzle for continuously ejecting ink particles, a charging electrode for selectively charging the ejected ink particles with a pulse potential, a deflecting electrode for forming a constant electric field, and non-charging. A print processing system having a gutter for collecting unnecessary ink particles.
With such a configuration, the ink particles are continuously ejected from the ejection nozzles, the ejected ink particles are selectively charged at a pulse potential by the charging electrode, and the charged ink particles pass between the deflection electrodes. This causes the recording material A to be deflected in accordance with the charge amount and struck at a predetermined position on the object to be printed A, thereby forming a dot pattern on the object to be printed and performing the printing process.

The printer head 1 includes a laser light source 11 that emits a visible laser beam, which is visible coherent light, and a diffraction device that projects a reference pattern B onto a printing surface of an object A by irradiation of the visible laser beam. An optical system (printing position indicating device) having the optical element 12 is provided. This optical system is a diffractive optical system in which the optical surface is perpendicular to the bisector of the deflection angle (projection angle) θ of the ink particle on the intersection of the maximum trajectories L ₁ and L ₂ of the ejection of the ink particle. An element 12 is arranged, and a laser light source 11 is arranged behind the diffractive optical element 12.

The maximum trajectory L of the printer head 1
_1, the portion sandwiched by other than the area in L _2, a mask material 13 for shielding the visible laser beam is formed. The light projection pattern from the diffractive optical element 12 outside the range in which the ink particles fly out is blocked by the mask material 13 so as not to reach the object to be printed A. 1. Even if the distance between the objects A fluctuates, the deflection angle (projection angle) of the ink particles always becomes equal to the spread angle of the light projection pattern from the diffractive optical element 12 to the object A. Therefore, for example, when the distance between the printer head 1 and the printing object A is long and the printing area is widened, the printing object A
Similarly, the pattern of light projected on the image is spread, and the printing position can be accurately recognized.

The spread angle of the light projection pattern from the diffractive optical element 12 to the printing object A does not necessarily need to be larger than the deflection angle (projection angle) of the ink particles. When instructing the printing position on the printing target A, for example, the lowest printing position of each character may be indicated. In such a case,
Even if the spread angle of the light projection pattern is smaller than the deflection angle (projection angle), an accurate printing position can be recognized.

With such a structure, the visible laser light emitted from the laser light source 11 is irradiated on the diffractive optical element 12 to project the reference pattern B on the printing surface of the printing object A. FIG. 2 shows an example of the reference pattern B. FIG.
The reference pattern B shown in (a) is a lattice pattern,
The reference pattern B shown in FIG. 2B is a concentric pattern. Further, still another example of the reference pattern B is shown in FIG. The reference pattern B shown in FIG. 3A is a linear pattern, the reference pattern B shown in FIG. 3B is a dot pattern, and the reference pattern B shown in FIG. is there. Note that these are only examples, and the reference pattern B is, of course, not limited as long as the pattern can recognize the printing position.

Next, the operation will be described. Ink particles are continuously ejected from the ejection nozzle, and a part of the ejected ink particles is charged by the charging electrode, and the charged ink particles pass through between the deflecting electrodes, and correspond to the charge amount. Is deflected at a deflection angle (protrusion angle) θ, protrudes out of the printer head 1 and strikes a predetermined position of the printing object A that moves in a direction perpendicular to the deflection direction. As a result, the predetermined dot pattern is
And characters, symbols, figures, and the like are printed. The remaining ink particles that are not charged by the charging electrode are collected by a gutter and reused.

On the other hand, the visible laser light emitted from the laser light source 11 is applied to the diffractive optical element 12, and is applied to the printing surface of the printing object A, for example, as shown in FIG. 2 (a), (b) or FIG. ,
A reference pattern B as shown in (b) and (c) is projected. The user refers to the projected reference pattern B, adjusts the distance between the printer head 1 and the printing object A, and specifies the printing position. At this time, the printer head 1,
By changing the distance between the printing objects A, the printing range varies, but the deflection angle (projection angle) of the ink particles and the spread angle of the light projection pattern from the diffractive optical element 12 to the printing object A. Is always equal, the reference pattern B to be projected also changes according to the change in the printing range, and the printing range can be understood at a glance. Therefore, the printing range can be specified very easily.

[0026]

As described above, in the charge control type ink jet printer of the present invention, the reference pattern is formed on the object to which the deflected charged ink particles are struck by irradiating the diffractive optical element with the visible laser light. Since the projection is performed, the printing position (printing height) can be visually recognized, the printing position designation processing can be performed quickly and accurately, and the optimum printing conditions can be set. It is possible to set in a short time. In addition, it is not necessary to perform fine adjustment while repeating test printing as in the related art, and the amount of ink consumption when setting printing conditions can be significantly reduced.

Further, in the charge control type ink jet printer of the present invention, the light projection pattern from the diffractive optical element to the object to be printed is set to be larger than the deflection angle (spread angle) of the ink particles. Therefore, the magnitude of the deflection angle (spread angle) of the ink particles is equal to the spread angle of the projection pattern from the diffractive optical element. It is possible to visually confirm an accurate printing area, and it is possible to more efficiently set optimum printing conditions.

Since the lattice pattern or the concentric pattern is used as the reference pattern, the printing position can be more easily specified.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a printer head of a charge control type ink jet printer of the present invention.

FIG. 2 is a schematic diagram showing an example of a reference pattern projected on a printing object.

FIG. 3 is a schematic diagram showing an example of a reference pattern projected on a printing object.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer head 11 Laser light source 12 Diffractive optical element 13 Mask material A Object to be printed B Reference pattern

Claims (6)

[Claims] 1. A charge control type ink jet printer for selectively charging ink particles continuously ejected, deflecting the charged ink particles and hitting the object to be printed to perform a printing process. A charge control type ink jet printer comprising: a light source that emits light; and a diffractive optical element that projects a reference pattern for indicating a printing position onto the object by irradiating visible coherent light from the light source. . 2. The charge control type ink jet printer according to claim 1, further comprising: means for blocking visible coherent light from the diffractive optical element to the object to be printed, which is at an angle larger than the deflection angle of the ink particles. . 3. The charge control type ink jet printer according to claim 1, wherein the reference pattern is a lattice pattern or a concentric pattern. 4. A method for selectively charging continuously ejected ink particles and deflecting the charged ink particles to strike the object, thereby performing a printing process. In an apparatus for designating a printing position, a light source that emits visible coherent light, and diffraction for projecting a reference pattern for designating the printing position on the object by irradiation of visible coherent light from the light source. A printing position indicating device, comprising: an optical element. 5. The printing position indicating apparatus according to claim 4, further comprising means for blocking visible coherent light from the diffractive optical element to the object to be printed which has an angle larger than the deflection angle of the ink particles. . 6. The printing position indicating device according to claim 4, wherein the reference pattern is a lattice pattern or a concentric pattern.