JP2846743B2 - Small print evaluation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small print evaluation apparatus used to evaluate the transfer characteristics of characters printed on a recording medium by using electrostatic printing, a laser printer, a thermal transfer device, or the like.

[0002]

2. Description of the Related Art Printing devices used for the above purposes are already known. For example, Japanese Patent Application No. 1-178158, Japanese Patent Application No. 1
See -178159. In this case, a print on a recording medium (usually plain paper is used) is optically formed by an optical system, and the image is formed by a photoelectric detector (mainly a CCD image pickup detector).
Is converted into an electric signal, and the printing state is evaluated electrically. In this apparatus, it is necessary to move the paper relative to the imaging optical system in order to evaluate the printing state over a wide range of the paper. This moving mechanism also requires a position detection system that detects the relative measurement position with considerable accuracy.

In recent years, along with the development of copying machines, word processors, and the like, the above-mentioned electrostatic printing, laser printers, and printing apparatuses using thermal transfer have been used in a very large number and various types. In the development of these devices, it is necessary to inspect the printing state of characters actually printed from multiple sides, and a highly accurate and multifunctional printing evaluation device has been manufactured.

[0004] However, in the current situation in which this type of printing apparatus is mass-produced, general inspection standards are used for final inspection of products on a manufacturing line or maintenance management of the printing apparatus used at a delivery destination. More and more, it is increasingly necessary to evaluate the state of the device according to this criterion. These inspection items include, for example, average density in the visual field, line width measurement, line density measurement, MTF (black and white contrast)
Measurement, line edge roughness measurement, line density gradient measurement, toner scattering, character thickness thinning measurement, etc. (These measuring methods are described, for example, in Japanese Patent Application No. 1-181715).
8, see Japanese Patent Application No. 1-178159). In this kind of general-purpose use, an expensive large-scale device having a variety of functions as a print evaluation device as originally was inconvenient.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a small-sized printing evaluation device which has a limited function, is easy to operate, and can measure in a short time.

[0006]

According to the present invention, an optical system 6 movable relative to a CCD unit 7 and an illumination lamp 5 for illuminating a measurement field P of a sheet 2 to be tested are provided. This problem is solved by a small-sized printing evaluation device in which a transparent cylinder 4 connected to a support flange 3 placed on a sheet 2 is connected to the lower end of the imaging body 9.

[0007] Another advantageous configuration is disclosed in claim 2.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing one embodiment.

FIG. 1 shows a main part of an image forming apparatus and a measuring head of a small print evaluation apparatus according to the present invention. This measuring head is
It is placed on the inspection paper 1 placed on a flat place.
The measuring head is formed in a substantially cylindrical shape, and is provided with a support flange 3 which can be stably mounted on the lower end of the measuring head. A transparent cylinder 4 is connected to the flange 3. On the transparent cylinder 4 is mounted an imaging body 9 having a main part of the imaging system according to the present invention. That is, a focusing lens 6 for forming an image of the visual field P of the sheet 1 on an imaging detector, here, a CCD unit 7, and the CCD unit 7 are disposed in the imaging body 9. In order to satisfy the above-mentioned optical conditions, the focusing lens 6 is connected to the imaging body 9 via the screw groove 12.
Is fixed inside a lens support cylinder 11 which moves relatively to the lens. A drive mechanism such as a lever for driving the rotation of the lens support cylinder 11 is not shown in FIG. 1 to avoid complexity.

One or more illumination lamps 5 are arranged symmetrically with respect to the axis of the body 9 to illuminate the area of the field of view P of the paper 1. The illumination lamp 5 may be a ring-shaped incandescent lamp (halogen lamp) or a plurality of xenon lamps arranged symmetrically with respect to the axis. Of course, in order to increase the illumination efficiency and at the same time reduce the penetration of radiant heat inside the main body 9, it is advantageous to provide one or more reflectors 13 respectively corresponding to the back of the illumination lamp 5.

Further, in the small-sized printing evaluation apparatus according to the present invention, since the inspection position of the paper 1 can be determined by visual observation, the lower part of the main body 9 is not only formed by the transparent cylinder 4 already described, A flat plate 2 made of a transparent material is provided. At the edge of the flat plate 2 on the side of the visual field P,
A scale P is provided so that the position of the visual field P can be determined more accurately. In order to prevent disturbance light from entering during measurement, a transparent cylinder 4 and a light-blocking slide cylinder 8 made of an opaque material movable up and down are provided outside the main body 9 following the cylinder. Although a stopper or the like for restricting the movement position of the cylinder 8 is not shown in FIG. 1, the slide cylinder 8 is lifted up at the time of initial setting, and the inspection position is determined within the visual field P. Next, the slide cylinder 8 is lowered, and measurement is started so that light does not enter the visual field P from the outside.

A driving power supply to be introduced into the CCD unit 7 and a detection signal supplied from the CCD unit 7 are connected to an operation / display unit 20 which is schematically shown in FIG. doing.

FIG. 2 shows a front panel of the operation / display unit 20 of the printing evaluation apparatus. Measurement field of view P is C
It comprises a display unit (for example, a CRT or a liquid crystal TV display device) for displaying a screen imaged by the CD unit 7, a numeric display unit 22 for numerically displaying measurement results, and operation keys 26. When any one of these operation keys 26 is pressed, the following measurement items (1) average density in the visual field (2) line width measurement (3) line density measurement (4) MTF (black and white contrast) measurement (5 ) Line edge roughness measurement (6) Line density gradient measurement (7) Toner scattering (8) Character thinning measurement can be selected. These electric processes and the like have already been described in detail in Japanese Patent Application Nos. 1-178158 and 1-178159.

As already described with reference to FIG. 1, the small print evaluation apparatus according to the present invention is placed directly on the sheet 1 to be inspected, and does not have a moving mechanism for relatively moving the imaging body and the sheet relative to each other. . The moving mechanism itself is complicated and large, and it is necessary to provide a highly accurate position reading detection unit. However, these devices are omitted in the small print evaluation apparatus according to the present invention. Therefore, the measurement is limited to the area determined by the detection surface of the CCD, for example, 4 × 4 mm ² and the magnification of the optical system.

[0015]

The advantages obtained by the small-sized printing evaluation apparatus according to the present invention are as follows. Since a moving mechanism is not provided between the sample and the imaging body, the apparatus is significantly simplified, the operation is easy, the cost is reduced, and the maintenance is reduced. Becomes easier. In addition, since the scanning area of the CCD has a sufficient area in many cases, highly reliable evaluation results can be obtained. Therefore, it is particularly suitable for manufacturing sites, maintenance services, and the like.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a main part of an imaging main body in an embodiment of a small print evaluation apparatus according to the present invention.

FIG. 2 is a schematic plan view showing a front panel of a corresponding scanning / display unit.

[Description of Signs] 1 Sample 2 Positioning plate 3 Support flange 4 Transparent cylinder 5 Illumination lamp 6 Lens system 7 CCD unit 8 Slide cylinder 9 Imaging body 10 Cable 11 Lens support cylinder 12 Screw groove 13 Reflector S Scale 20 Operation / display unit 22 Numeric display 24 Image display 26 Operation keys

Claims (2)

(57) [Claims] An optical system (6) that can move relatively to a CCD unit (7) and an illumination lamp (5) for illuminating a measurement field of view (P) of a sheet to be tested (2) Transparent cylinder 4 connected to supporting flange 3 to be placed
A small-sized printing evaluation device, characterized by being connected to a printing device. 2. A transparent positioning plate 2 having a scale S for reading the position of a field of view P is connected to the support flange 3, and a light-shielding slide that moves up and down is provided on the outer periphery of the transparent cylinder 4. The small-sized printing evaluation device according to claim 1, wherein a cylinder (8) is provided.