JPS63261305A - Light converging bar for synchronizing signal generation - Google Patents

Abstract

PURPOSE:To prevent light convergence efficiency from decreasing by embedding parts which diffuse light lengthwise in a light converging bar made of a transparent material which propagates light incident from a flank toward its end surface in the lengthwise direction. CONSTITUTION:The light converging bar 1 for synchronizing signal generation has a long-sized columnar light converging bar 3 made of the transparent material for propagating the light incident from the flank toward its end surface in the lengthwise direction and the parts 2 which diffuse the light and are embedded lengthwise in the light converging bar. Namely, the light beam for synchronization which is incident on the light converging bar 3 through a grid 11 is diffused by the embedded parts 2 which diffuse the light and the diffused light is propagated in the light converging bar 3 and incident on a light receiving element to obtain a synchronizing signal. Consequently, the light convergence efficiency is prevented from decreasing.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a synchronizing signal generating condensing bar, particularly a synchronizing bar used in a light beam scanning device for reading and recording image information by scanning a light beam. This invention relates to a condensing bar for synchronizing signal generation.

<Prior Art and its Problems> In recent years, light beam scanning devices have been developed that read and/or record images using light beams. In a light beam scanning device that reads and/or records such images, a light beam emitted from a light source is generally reflected and deflected by an optical deflector and sent at a constant speed in a direction perpendicular to the direction of deflection. The object to be scanned (sub-scanned) is main-scanned.

In this case, keeping the scanning speed of the light beam constant is an important requirement to obtain good image quality. However, it is difficult to keep this strictly constant due to the mechanism of the device, so the position of the deflected light beam is usually detected according to the movement of the optical deflector, and a synchronization signal is generated based on this detection signal. A technique is used to generate and record or read the image signal.

For convenience, a conventional synchronizing signal generating device for obtaining such a position detection signal of scanning light will be described with reference to FIG. 5, which shows an embodiment of the present invention. A conventional synchronization signal generator includes a grid 11 in which bright areas and dark areas are arranged alternately on the optical path of a synchronization light beam L, and a long cylindrical column made of acrylic resin provided behind this grid. A light condensing bar 3' having a diffusion zone 2' formed in the longitudinal direction on the side opposite to the grid;
A device consisting of a light-receiving element 4 provided on the end face of the lens is used. In such a synchronization signal generating device, the first beam emitted from the laser light source 5 is the first beam emitted from the laser light source 5. passes through a beam expander 6 and is expanded to a desired beam diameter, and is deflected by an optical deflector 7.

The deflected light beam is a scanning beam L2 for main-scanning the scanned object 10 which is sub-scanned and conveyed in the direction B by the half mirror 9, and a synchronization light beam L1 for generating a synchronization signal.
The beam is split into the recirculating light beam L1, or passes through the grid 11 described in 1) 7r, enters the condensing bar 3', is diffused by the diffusion zone 2', and is further reflected and scattered inside the condensing bar 3'. After repeating this process, the light reaches one end of the light collecting bar and enters the light receiving element 4. The light incident on the light-receiving element 4 has a periodic change in the amount of light corresponding to the scanning of the bright and dark pattern of the grid 11, and the light-receiving element 4 converts the change in the amount of light into an electrical signal.
The stiffness allows a synchronization signal to be obtained. However, the diffusion band 2' formed on the surface of the condensing bar 3' used in such a synchronizing signal generator has conventionally had the following problems.

Conventionally, the diffusion zone 2' consisted of a coating film formed in a band shape with a predetermined width using a light-scattering paint in the longitudinal direction of the surface of the elongated cylindrical condensing bar 3', such as acrylic resin or glass. .

Here, the width of the diffusion zone 2' is preferably as narrow as possible in order to increase the light collection efficiency. If the width of the diffusion zone 2' is wide, the light that enters the condensing bar 3' and is diffused by the diffusion zone 2' repeats total reflection inside the condensing bar until it reaches the light receiving element 4. This is because the amount of light that is diffused and absorbed again in the diffusion band and finally reaches the light receiving element 4 decreases, resulting in a decrease in light collection efficiency.

Furthermore, when the diffusion zone 2' is formed in the longitudinal direction of the condensing bar 3', it is arranged strictly on the scanning line of the synchronizing light beam L1 that passes through the grid 11 and enters the condensing bar 3'. In order to do this, it is necessary that the diffusion band 2' be formed straight in the longitudinal direction of the condensing bar without distortion.

If the diffusion band 2' is distorted and there is a part in the diffusion band 2' that deviates from the scanning line of the synchronized moonlight beam L1, the light incident on the condensing bar 3' will not be diffused in that part and will be condensed. This is because the light passes through the bar 3'.

However, conventionally, when forming the diffuser 2', the part of the light collecting bar 3' where the diffuser 2' is formed is masked, and paint is applied by spraying or the like. The surface of the bar 3' has a predetermined narrow width with grain size
It is very difficult to form the diffusion zone 2';
There have been problems in that the width of the diffusion zone 2' becomes wide, or the diffusion zone 2' is not formed in the longitudinal direction at the end, resulting in a decrease in light collection efficiency.

On the other hand, in order to ensure that the light that enters the condensing bar 3' and reaches the diffusion zone 2' is diffused without passing through the diffusion zone 2', the light scattering properties of the diffusion zone must be The thicker the paint film formed, the better. Therefore, the diffusion zone 2' has conventionally been formed by applying light-scattering paint multiple times. This results in the diffusion band 2' having a thickness sufficient to prevent the transmission of incident light.

However, in such a layered diffusion band, the coating film tends to crack or peel, creating parts that allow incident light to pass through, making the amount of light detected by the light-receiving element 4 unstable. There was a problem.

<Objective of the Invention> The present invention is an attempt to solve the problems associated with the prior art, and the present invention aims to solve the problems associated with the prior art. In order to prevent the light from being reflected and absorbed by the diffusion band again before reaching the light-receiving element and reducing the light collection efficiency, the purpose is to form the diffusion band with a predetermined width with high precision.

Furthermore, in order to ensure that the light that enters the condensing bar and reaches the diffusion zone is diffused in the diffusion zone without being transmitted, the present invention has a sufficient thickness, and the thickness is stable. The purpose is to form a diffusion zone that is retained.

<Detailed Description of the Invention> According to the present invention, a light diffusing portion is embedded in the longitudinal direction of a light condensing bar made of a transparent material that propagates light incident from the side toward its end face along the longitudinal direction. Provided is a condensing bar for synchronizing signal generation, characterized in that:

In the above invention, it is preferable that the light diffusing portion is formed by forming a longitudinal groove on the side surface of the light collecting bar and injecting a light scattering material into the groove.

Preferably, the light-diffusing portion is formed by forming a longitudinal hole in the vicinity of the focal point inside the light collecting bar, and injecting a light-scattering material into this groove.

<Specific Structure of the Invention> Next, the synchronization signal generation condensing bar of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

1 to 3 are perspective views showing examples of aspects of the synchronization signal generation condensing bar of the present invention.

A condensing bar 1 for generating a synchronization signal according to the present invention includes a condensing bar 3 in the form of a long column made of a transparent material that propagates light incident from a side surface in the direction of its end face along the longitudinal direction, and a condensing bar 3 in the shape of a long column made of a transparent material. It has a light-diffusing portion 2 embedded in the longitudinal direction.

Note that the condensing bar 3 is not limited to a long cylindrical shape, but may be a long prismatic shape.

The material of the condensing bar 3 is not particularly limited as long as it is transparent and can transmit light, and acrylic resin, glass, engineering plastic, etc. can be used.

11. The light diffusing portion 2 corresponds to a conventional diffusion zone. That is, the synchronizing light beam that passes through the grid and enters the condenser bar is diffused by the light-diffusing portion 2 embedded in the condenser bar, and the diffused light propagates inside the condenser bar 3. The light is incident on the light receiving element, and a synchronization signal is obtained.

The light-diffusing portion is embedded in the longitudinal direction of the condensing bar, and its formation can take various forms as required.For example, the form shown in Figs. I can give it to you.

FIGS. 1(a) and 1(b) show an embodiment in which the light diffusing portion 2 is embedded in a longitudinal groove formed on the side surface of the condensing bar 3. FIG.

The light-diffusing portion 2 is created by first precisely forming a predetermined groove on the side surface of the condensing bar by milling, plastic molding, etc., and then filling this groove with a light-scattering material. Formed by injection.

The light-diffusing portion 2 of the invention is then formed by injecting a light-scattering material into the grooves thus formed.

As the light-scattering material, for example, a light-scattering paint made by adding a binder to a white pigment or the like is used in the same manner as in the case of forming a conventional diffusion zone.

Here, after the light-scattering material is injected into the groove, it may be back coated with a resin or the like.

In the present invention, as described above, the light-diffusing portion 2 is formed by forming a predetermined groove in the condensing bar 3 with high accuracy in advance, and then injecting a light-scattering material into the groove. It can be formed thinly and accurately. Further, the light-diffusing portion 2 is not a coating formed on the surface of the light-concentrating bar, but is a light-scattering material layer embedded in a groove leading to the light-condensing bar, so that cracks or peeling do not occur.

FIG. 2 shows an embodiment in which the light-diffusing portion 2 is embedded in a longitudinal groove formed on the side surface of the condensing bar 3 except for the ends thereof.

If the light-diffusing portion does not need to be formed to the end of the condensing bar 3, it is preferable to form the light-diffusing portion leaving the end portion as described above.

The embodiment shown in Fig. 2 is similar to the embodiment shown in Fig. 1, in that the light-diffusing portion 2 is formed by forming a predetermined groove accurately in the condensing bar 3 in advance, and then injecting a light-scattering material into the groove. formed by In this case, uniform J7 light is applied to the end of the condensing bar.
This eliminates the need to inject light scattering material, making the material injection process easier.

In FIGS. 3(a) and 3(b), the light diffusing portion 2 is
The embodiment is shown in which it is embedded in a longitudinal perforation formed near the focal point inside the light condensing bar 3.

This aspect is suitable when the side surface of the condenser bar is a curved surface that has a focal point within the condenser bar.

When using a condensing bar having a focal point inside the condensing bar 3 as in this embodiment and forming a portion 2 for diffusing light near the focal point, a cross-sectional view of the condensing bar in the circumferential direction is shown. As shown in FIG. 3(b), even if the synchronizing light beam L1 fluctuates within a range of 1' as shown by the dotted line, it will enter the light diffusing part 2 placed near the focal point, The incident light can be stably diffused even when the width of the light diffusing portion is narrow, regardless of the slight deviation of the synchronization light beam L1.

Therefore, even if the position of the synchronizing light beam L changes slightly due to the influence of shaft wobbling or surface tilt of the optical deflector, a stable synchronizing signal can be obtained, and the position of the focusing bar can be adjusted easily. This does not have to be carried out strictly, and there are advantages such as ease of assembling the light beam scanning device.

The condensing bar for synchronizing signal generation of the present invention can be applied to various light beam scanning devices in the same way as a condensing bar having a normal diffuser. Next, an embodiment of a light beam scanning device to which the synchronization signal generation condensing bar of the present invention is applied will be described with reference to the accompanying drawings.

FIG. 5 is a perspective view conceptually showing an embodiment of a light beam scanning device to which the synchronization signal generation condensing bar of the present invention is applied. This light beam scanning device basically uses a laser light beam L. A laser light source 5 generates a light beam, a beam expander 6 makes the light beam a desired diameter, and a light beam L. a rotating polygon mirror 7 for deflecting the beam, a scanning lens 8, a half mirror 9 provided on the optical path extending in the scanning direction, a sub-scanning conveyance means (not shown) for sub-manipulating the scanned object 10 in the direction B, and a light beam. A light-receiving element 4 such as a photodiode or the like is provided on the end face of the light-concentrating bar 1 for generating a synchronizing signal, and the light-receiving element 4, such as a photodiode, is provided on the end face of the light-converging bar 1 for generating a synchronizing signal, which is installed so that there is a light-diffusing part 2 on the side opposite to the side where the light is incident. have

Note that the +111 signal generating condensing bar 1 may be provided with a mirror at the end opposite to the end where the light receiving element is provided, if necessary. Further, light receiving elements can be provided at both ends of the condensing bar.

<Specific Effects of the Invention> Hereinafter, the effects of the above-mentioned light beam scanning device to which the signal generation condensing bar for signal generation according to the present invention is applied will be explained based on the drawings.

A light beam L emitted from a laser light source 5.

After passing through the beam expander 6 and reaching a desired beam diameter, the beam enters a rotating polygon i7 rotating in the direction of the arrow and is reflected and deflected.

Light beam L. In addition to the rotating polygon mirror 7, a galvanometer mirror, a hologram scanner, an AOD (acousto-optic optical deflector), or the like can be used as an optical deflector for deflecting the light.

The light beam L reflected and deflected by the rotating polygon mirror 7 passes through a scanning lens 8 such as an fθ lens provided on the optical path, and then enters a half mirror 9 provided on the optical path extending in the main scanning direction. .

This half mirror 9 receives the incident light beam L.

Among them, the amount of light beam necessary for scanning is used as the scanning light beam L.
2, and the remaining light beam is transmitted as a position detection light beam of the scanning light beam, that is, a synchronization light beam L1. The scanning light beam L2 reflected by the half mirror 9 is focused on the object to be scanned 10 disposed on the optical path, and is conveyed (sub-scanned) in the direction of arrow B and passes over the object to be scanned 10 in the direction of arrow C. Main scan repeatedly in the direction.

On the other hand, the synchronization light beam L transmitted through the half mirror 9
, scans a grid 11 arranged at a conjugate position with respect to the object to be scanned 10 and the half mirror 9, and the light beam transmitted through the grating of the grid 11 is transmitted to the condensing bar 1 for synchronizing signal generation according to the present invention. incident on .

The incident light beam is diffused by the light diffusing portion 2, as shown in FIG. The light enters a light receiving element 4 such as a photodiode provided on the end face of the light collecting bar 3 while undergoing total reflection.

The grid 11 is formed by chromium vapor deposition or the like into a lattice-like pattern of parts that transmit light and parts that do not transmit light at a pitch corresponding to the pixels. It changes periodically with the main scanning of the light beam L2. Therefore, the light-receiving element 4 detects periodic changes in the synchronizing light beam L, and this change in light amount is converted into an electrical pulse signal by a synchronizing signal generating means (not shown) to obtain a synchronizing signal.

In the above embodiment, the light beam L0 emitted from the laser light source 5 is deflected by the rotating polygon 'm7, and the scanning lens 8
After passing through the scanning light beam L2, the half mirror 9
and synchronization light beam L1,
The light beam L0 incident on the rotating polygon mirror 7 may be split into two parts, each of which may be incident on a separate reflecting surface of the rotating polygon i7. Furthermore, it is also possible to provide separate light sources for the scanning light beam and the synchronization light beam. In this case, if the scanning light beam and the synchronization light beam have different wavelengths, a dichroic mirror or the like can be used. It is also possible to combine them into the same optical path using , and then split them again.

In either embodiment, a synchronization signal corresponding to the scanning of the scanning light beam can be obtained using the synchronization signal generation focusing bar of the present invention.

<Effects of the Invention> According to the present invention, regarding a light focusing bar used in a synchronization signal generator used in a light beam scanning device, etc., the light diffusing portion is formed with a predetermined width and grain size. , the light that enters the condensing bar and is once diffused by the diffusion band undergoes total internal reflection inside the condensing bar until it reaches the light-receiving element, where it is reflected and absorbed again by the diffuser, increasing the condensing efficiency. can be prevented from decreasing.

In addition, in the present invention, the paint layer in the part that diffuses light has a sufficient thickness, and this thickness is maintained stably without cracking or peeling, so the light enters the light condensing bar. It is possible to reliably diffuse the light that reaches the part where it is being diffused without transmitting it.

Furthermore, since the light-diffusing portion is formed by injecting a light-scattering material into a predetermined groove formed in advance,
The amount of light-scattering paint used can be reduced compared to the formation of a diffusion zone by conventional painting.

In the aspect of the present invention in which the light diffusing portion is formed in the longitudinal direction near the focal point inside the condenser bar, even if the optical path of the light beam incident on the condenser bar has a large deviation, the incident light beam can be stabilized. It can be spread out, and adjustment during assembly is also facilitated.

[Brief explanation of drawings]

FIG. 1(a) is a perspective view showing one embodiment of the synchronizing signal generating condensing bar of the present invention, and FIG. 1(b) is a sectional view thereof. FIG. 2 is a perspective view showing another embodiment of the synchronization signal generation condensing bar of the present invention. FIG. 3(a) is a perspective view showing another embodiment of the condensing bar for synchronizing signal generation of the present invention, and FIG. 3(b) is a sectional view thereof. 4th [', RJ is an explanatory diagram for explaining the function of the synchronization signal generation condensing bar of the present invention. FIG. 5 is a perspective view conceptually showing an embodiment of a light beam scanning device to which the synchronization signal generation condensing bar of the present invention is applied. Explanation of symbols 1... Focusing bar for synchronizing signal generation, 2... Part that diffuses light, 2'... Diffusion band, 3... Focusing bar'-1 4... ... Light receiving element, 5... Laser light source, 6... Beam expander, 7... Rotating polygon mirror, 8... Scanning lens, 9... Half mirror 1 10... ...Object to be scanned, 11...Grid, Lo...Light beam, L...Light beam for synchronization, L2...Light beam for scanning

Claims (3)

[Claims] (1) A synchronization signal characterized in that a light-diffusing part is embedded in a light-diffusion bar made of a transparent material that propagates light incident from the side in the longitudinal direction toward its end face. Light collection bar for generation. (2) The light diffusing portion is formed by forming a longitudinal groove on the side surface of the condensing bar, and injecting a light scattering material into the groove. Focusing bar for synchronization signal generation described in . (3) The light diffusing portion is formed by forming a longitudinal hole in the vicinity of the focal point inside the condensing bar, and injecting a light-scattering material into this groove. 1
Focusing bar for synchronization signal generation as described in .