JPH064319Y2 - Printing device for evaluation of conveyance accuracy of image recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention determines whether or not the feeding accuracy of a conveying means for a photosensitive material such as a film is good in an image scanning recording apparatus such as a flat scanner or a copying machine using a laser light source. A device for evaluating.

[Conventional technology]

In an optical scanning type image recording device such as a flat scanner, a photosensitive material conveyed in a fixed direction (hereinafter, referred to as a sub-scanning direction) at a fixed speed is changed by a laser beam that changes in intensity according to an image density signal. Exposure is performed while repeatedly scanning light rays such as the above with a predetermined width in the direction perpendicular to the sub-scanning direction (hereinafter referred to as the main scanning direction) to perform planar image recording.
At this time, if there is unevenness in the feeding of the photosensitive material to the feeding means, that is, if there is a change in the feeding speed, unevenness in the pitch between the scanning lines (hereinafter referred to as feeding unevenness) occurs, and the uniformity of the image is impaired. Distorts the image. It has a great influence on the image quality of the duplicated image. Further, when the duplicate image is an image with a regular halftone dot array such as a mesh plate, if the above-mentioned unevenness in feeding is regular, another unevenness occurs in the duplicate image due to the so-called moire phenomenon, and the image quality is To make things worse.

In these cases, of course, it is necessary to evaluate the quality of the feeding accuracy of the conveying means of the image recording apparatus, and if necessary, adjust the apparatus to reduce and suppress the unevenness of feeding within an allowable range.

[Problems to be solved by the invention]

Therefore, various speed measuring instruments, such as a laser Doppler speed meter, are used to continuously measure the carrier speed, the resulting signal is passed through a spectrum analyzer to extract the speed frequency component, and the carrier is analyzed by analyzing it. There is a method of measuring the feeding accuracy of the means and directly inspecting / determining.

However, in the method as described above, it is necessary to perform high-accuracy speed measurement despite the extremely low transport speed, which inevitably results in an enormous amount of data, which makes analysis and determination difficult, so that method should be used. The applicable cases are extremely limited.

Therefore, in general, an actual image recording apparatus is driven to print a photosensitive material with light having a constant intensity and the result is visually evaluated. It is difficult to make an accurate evaluation of feed accuracy alone. The reason is that, for example, in the case of a flatbed scanner,
The main causes of uneven scanning in the sub-scanning direction are not only uneven feeding of the photosensitive material, but also unstable in the scanning trajectory due to the mechanism for scanning light (for example, due to pyramid error in polygon mirror). This is because, as these are combined and appear as unevenness such as uneven feeding on the photosensitive material, it is not possible to independently evaluate the feeding accuracy of the photosensitive material.

It is a technical object of the present invention to provide an apparatus capable of visually evaluating the quality of only the feeding accuracy of a photosensitive material without using the above method.

[Means for solving problems]

As a technical means for achieving the above-mentioned object, the present invention provides a device for evaluating the feeding accuracy of a conveying means of a scanning image recording device, a light beam generator, and a light beam emitted from the light beam generator. Intermittent means that is intermittent in a fixed cycle,
The light beam emitted from the interrupting means is converted into a light flux whose cross section forms a line segment in the main scanning direction (direction orthogonal to the transport direction of the photosensitive material transported by the transport means), and the surface of the photosensitive material is converted. It is characterized in that it is composed of an optical system for irradiating the film with a light, and a general-purpose photosensitive film is used as the photosensitive material.

[Action]

The light beam emitted from the light beam generator attached to the image recording device is intermittently cut at a constant period by the interrupting means, and is further converted by the optical system into a light beam whose cross section is a line segment in the main scanning direction. When the surface of a moving photosensitive material is irradiated, the light beam is interrupted first, and the photosensitive material is exposed by the distance traveled by the photosensitive material within the time during which the light beam in the light beam is emitted, and the exposure of a certain width is performed. A band is formed. Next, an unexposed zone is formed by the distance that the photosensitive material moves within the time when the emission of the light beam is stopped.
The line-shaped exposure in the main scanning direction is repeated intermittently, whereby a pattern in which exposure bands having a constant width corresponding to the scanning lines are arranged in parallel at a constant pitch is printed on the photosensitive material.

At this time, when the precision of feeding the photosensitive material by the transporting means is sufficiently high, a pattern in which the exposure bands of exactly the same width are arranged side by side at an extremely accurate pitch is formed by exposure, but the feeding precision is poor and uneven feeding occurs. In some cases, a pattern in which the intervals between the exposure bands are not regular is formed by exposure according to the unevenness of the feed. By developing the pattern thus formed by exposure and visually evaluating the output pattern drawn on the photosensitive material, it is possible to evaluate and determine the feeding accuracy of the conveying means.

〔Example〕

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing a schematic configuration of an embodiment according to the present invention. However, the conveying means of the image recording apparatus is not shown. This determination device is a light beam generator 1
0, an acousto-optic modulator (AOM) 12 and an optical system 14. As the light beam generator 10, helium-
A neon laser (He-Ne laser) is used, but other various lasers or light sources may be used. The laser beam L emitted from the He-Ne laser 10 is incident on the AOM 12 and also
A rectangular wave signal (ON / OFF pulse signal) having a required frequency and duty ratio from the pulse generator 16 input to the pulse generator 12 causes the laser beam L _{1 to} be emitted in a pulsed manner from the AOM 12 in a pulsed manner. The optical system 14 includes mirrors 18 and 2.
0, a beam expander 22, and cylindrical lenses (cylindrical lenses) 24 and 26. The beam expander 22 expands the beam diameter of the laser beam L ₁ to convert it into a parallel focused laser beam L ₂ and lens
Reference numerals 24 and 26 convert the beam shape of the parallel focused laser beam L ₂ into a parallel focused laser beam L ₃ having a line segment shape in cross section.

Next, the operation of this apparatus and the method of evaluating the feed accuracy will be described. First, a photosensitive material 28 such as a film is loaded in an image recording device, for example, a flat scanner, and the conveying means is driven so that the photosensitive material 28 moves in the arrow direction (corresponding to the sub-scanning direction). When the laser beam L is emitted from the He-Ne laser 10 in this state, the laser beam L is modulated by the AOM 12 based on the rectangular wave signal from the pulse generator 16 and emitted intermittently at a constant cycle. It becomes L ₁ . At this time, the pulse generator 16 selects and transmits a rectangular wave pulse signal having a required frequency and duty ratio (these will be described later) corresponding to the transport speed of the image recording apparatus whose feed accuracy is to be evaluated. To be done. The laser beam L ₁ emitted intermittently from the AOM ₁₂ is totally reflected by the mirrors 18 and 20, and the beam expander 2
The beam diameter is enlarged by 2 and then the laser beam L having a sectional line segment shape is formed by the cylindrical lenses 24 and 26.
_It is converted into ₃ and is irradiated onto the surface of the moving photosensitive material 28. The photosensitive material 28 is linearly exposed by this irradiation, but since the photosensitive material 28 moves a certain distance in the direction of the arrow within the time during which the laser beam L ₃ is irradiated, the moving distance plus the linear-segment-shaped light flux. An exposure band having a width corresponding to the width is formed. Then, when the irradiation of the laser beam L ₃ is interrupted, the photosensitive material 28 moves in the direction of the arrow even within the interruption time, so that the photosensitive material 28 remains unexposed by the movement distance. Then, when the surface of the photosensitive material 28 is irradiated again with the laser beam L _3, an exposure band having a constant width is formed, and further, an unexposed band is formed subsequently. By repeating the above process, the patterns shown in FIGS. 2-1 and 2-2 are printed on the photosensitive material. In these figures, the shaded portions are the exposed zones E and E ', and the strip-shaped portions formed between the exposed zones E and E'are the unexposed zones N and N'. Of these, the one shown in FIG. 2-1 is the output pattern when a rectangular wave signal with a duty ratio of 50% is input from the pulse generator 16 to the AOM 12, and the one shown in FIG. , Is an output pattern when a rectangular wave signal having a duty ratio of 75% is input from the pulse generator 16 to the AOM 12. If the feeding accuracy of the photosensitive material by the transporting means of the image recording apparatus is sufficiently high, for example, in the pattern of FIG. The width m of the exposure band N becomes equal. This also applies to the width 1'of the exposure band E'and the interval m'in FIG. 2-2. However, if there is uneven transport speed,
The widths l and l'of the exposure zones E and E'and the pitch intervals m,
Since m'is irregular, a regular pattern cannot be drawn.

That is, if the feed accuracy is good, the output pattern (developed in the case of film etc.) will be uniform and uniform overall, but if the feed accuracy is poor, the output pattern will be uneven depending on the degree. Will be recognized.

Conversely speaking, it is necessary that the output pattern is formed by exposure so that this unevenness can be visually evaluated, and therefore the intermittent frequency and duty ratio described above are determined. By the width W (not shown) in the sub-scanning direction of the split laser beam L ₃ ,
It is decided relatively.

Normally, it is determined so that the intermittent frequency is not too high with respect to the transport speed and the exposure zones do not sequentially overlap with each other (a state where no unexposed zone is formed). This does not apply as long as the irregularity (unevenness) in the output pattern is set to be visible.

If the regularity is evaluated by observing the output pattern as described above, it is possible to evaluate the quality of the feeding accuracy of the conveying means. In the above example, the unevenness of the feed was visually evaluated, but if necessary, the pitch of the output pattern may be measured with a general-purpose optical measuring device to quantitatively evaluate the regularity. It's easy.

[Effect of device]

Since this device is constructed and operates as described above,
It is possible to easily evaluate the quality of only the feeding accuracy of the conveying unit of the image scanning recording apparatus.

[Brief description of drawings]

FIG. 1 is a perspective view showing the schematic construction of a printing apparatus for feeding accuracy evaluation of a conveying means of an image recording apparatus according to an embodiment of the present invention, and FIGS. 2-1 and 2-2 are respectively shown in FIG. It is an output pattern figure obtained using an apparatus. 10 …… optical beam generator (laser), 12 …… acousto-optic modulator, 14 …… optical system, 16 …… pulse generator, 22 …… beam expander, 24,26 …… cylindrical lens , 28 …… Photosensitive material.

Claims (2)

[Scope of utility model registration request] 1. A light beam generator, an interrupting means for interrupting a light beam emitted from the light beam generator at a constant cycle, and a cross-sectional shape of a light beam emitted from the interrupting means at a constant cycle. Printing for conveying accuracy evaluation of an image recording device, which comprises an optical system for converting the photosensitive material conveyed by the conveying means of the image recording device into a line segment in a direction orthogonal to the conveying direction and irradiating the surface of the photosensitive material. apparatus. 2. A printing apparatus for transport accuracy evaluation of an image recording apparatus according to claim 1, wherein the optical system comprises a combination of a beam expander and a cylindrical lens.