JPS63261304A - Light converging bar for synchronizing signal generation - Google Patents

Abstract

PURPOSE:To reduce the manufacture cost of a light converging bar and to facilitate the adjustment of a light beam scanner by providing parts which diffuse incident light in the surface of the light converging bar at specific intervals in the lengthwise direction of the light converging bar. CONSTITUTION:The light converging bar 1 for synchronizing signal generation has a long-sized columnar light converging bar made of a transparent material and the parts 2 which diffuse the incident light and are formed at the specific intervals in the lengthwise direction of the light converging bar. The material of the light converging bar is not limited specially as long as the material provides optical transmission and is transparent, and acrylic resin, glass, etc., are usable. The parts 2 which diffuse the incident light use light-scattering paint, etc., and are formed on the surface of the light converging bar in a specific shape at the specific intervals by printing, coating, etc. Consequently, the need for a grid is eliminated, the manufacture cost is reduced, and the light beam scanner is easily adjusted.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a converging bar for generating a synchronizing signal, particularly a synchronizing signal used in a light beam scanning device that reads or records image information by scanning a light beam. This invention relates to a condensing bar for generating synchronizing signals.

<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.

Conventionally, a synchronization signal generating device for obtaining such a position detection signal of scanning light uses a grid in which bright areas and dark areas are arranged alternately on the optical path of a synchronization light beam as shown in Fig. 3. 11, a long cylindrical condensing bar 12 made of acrylic resin or the like provided behind the grid, and a light receiving element 3 provided on the end face of the condensing bar 12. In such a synchronization signal generating optical device, a light beam 5 emitted from a light source 4 is transmitted to a beam expander 6.
After the beam passes through and has a desired beam diameter, it is deflected by the optical deflector 7, and the deflected light beam is sub-scanned and conveyed in the B direction by the half mirror 9. The synchronizing light beam 5A is split into a scanning light beam 5B for main scanning and a synchronization light beam 5A for generating a synchronization signal, and the synchronization light beam 5A passes through the grid 11' and enters the condensing bar 12, where it is focused. While repeating reflection and scattering inside the light bar 12, the light reaches the end of the condensing bar 12 and enters the light receiving element 3. The light incident on the light-receiving element 3 has a periodic change in the amount of light according to the scanning of the bright and dark pattern of the grid 11, and the light-receiving element 3 converts the change in the amount of light into an electrical signal, thereby generating a synchronization signal. I'm trying to get that.

However, the grid used in such a photodetector is made by depositing a large number of stripes of chromium or the like in parallel on a glass substrate, and is expensive to manufacture.

On the other hand, the light-condensing bar 12 is provided with a light diffusion band 12a in the longitudinal direction on the opposite side from the grid as shown in the figure.
This consists of a film of light-scattering paint applied to the side surface of the condenser bar 12, and the light that has passed through the grid 11 and enters the condenser bar 12 is diffusely reflected on its surface, and the light is reflected inside the condenser bar 12. This is to propagate by total reflection.

Therefore, it is necessary to provide a grid and a focusing bar, respectively. When arranging them, the grid is placed on the scanning line of the synchronizing light beam, and the light of the focusing bar is roughly placed on the optical path of the light transmitted through the grid. It is necessary to arrange the grid so that the diffusion zone 12a is located, and there is an inconvenience that the grid and the condensing bar must be adjusted respectively.

<Object of the Invention> The present invention aims to solve the problems associated with the prior art as described above, and it is an object of the present invention to provide a grid function to a light diffusion band of a condensing bar for generating a synchronization signal in a light beam scanning device. The purpose of this invention is to eliminate the need for conventional grids, thereby reducing the manufacturing cost of expensive grids, and to facilitate adjustment in the light beam scanning device.

<Brief Description of the Invention> According to the present invention, there is provided a light condensing bar made of a transparent material that propagates a light beam incident from the side toward its end face along the longitudinal direction, There is provided a condensing bar for synchronizing signal generation characterized by having portions for diffusing incident light formed at predetermined intervals in the longitudinal direction of the condensing bar.

<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.

FIG. 1 is a perspective view conceptually showing an embodiment of a light beam scanning device incorporating a condensing bar for synchronizing signal generation according to the present invention. Here, the same components as those of the light beam scanning device incorporating the conventional synchronizing signal generator shown in FIG. 3 are given the same reference numerals. This light beam scanning device basically consists of:
A laser light source 4 that generates a laser light beam 5, a beam expander 6 that makes the light beam a desired diameter, a rotating polygon mirror 7 that deflects the light beam 5, and a half mirror 9 that extends in the scanning direction on the optical path. , a sub-scanning transport means (not shown) for sub-scanning the scanned object 10 in the direction B, and a part 2 for diffusing light on the surface opposite to the side on which the light beam is incident. It has a condensing bar 1 for generating a synchronizing signal and a light receiving element 3 such as a photodiode provided on the end face of the condensing bar 1.

Here, the condensing bar 1 for synchronizing signal generation of the present invention includes a long cylindrical condensing bar made of a transparent material and a condensing bar formed at predetermined intervals in the longitudinal direction of the condensing bar to diffuse incident light. It has part 2.

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

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

The portions 2 for diffusing the incident light are provided on the surface of the condensing bar in a predetermined shape and at predetermined intervals by printing, coating, or other methods using a light-scattering paint or the like. Alternatively, fine light-diffusing unevenness may be formed on the surface of the condensing bar in a predetermined shape and at predetermined intervals by a mechanical method such as thermal processing or molding.

The shape and spacing of the light-diffusing portion 2 are adjusted appropriately depending on the diameter or length of the condensing bar. For example, if the condensing bar has a diameter of 15 mm and a length of 420 mm, a rectangular light-diffusing portion with a length of 1.5 mm in the circumferential direction of the condensing bar and a width of 400 Atm in the longitudinal direction of the condensing bar is used. , it is preferable that a large number of them be arranged in a grid pattern at intervals of 400 μm in the longitudinal direction of the condensing bar.

Here, the intervals between the light diffusing portions 2 are set to correspond to one pixel or several pixels. The amount of light incident on the condensing bar is converted into an electrical signal by the light receiving element 3 and becomes a synchronization signal, so as long as it has a certain relationship, it does not necessarily have to be a one-to-one relationship with the pixel. .

Note that a mirror may be provided on the synchronizing signal generation condensing bar 1 at the end opposite to the end where the light-receiving element 3 is provided, or the light-receiving element may be provided at both ends.

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

A light beam 5 emitted from a laser light source 4 passes through a beam expander 6 to have a desired beam diameter, and then enters a rotating polygon mirror 7 that rotates in the six directions of arrows, where it is reflected and deflected. . As an optical deflector that deflects the light beam 5,
In addition to this rotating polygon mirror 7, there is also a galvanometer mirror, a hologram scanner, and an AOD (acousto-optic optical deflector).
etc. are available.

The light beam 5 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 passes through a half mirror provided on the optical path extending in the main scanning direction.
9.

Of the incident light beam 5, this half mirror 9 reflects the amount of light beam necessary for scanning as a scanning light beam 5B, and uses the remaining light beam as a position detection light beam of the scanning light beam, that is, for synchronization. It is transmitted as a light beam 5A.

Scanning light beam 5B reflected by half mirror 9
is focused on the scanned object 10 placed on the optical path, and the arrow B
The object 10 to be scanned, which is conveyed (sub-scanned) in the direction, is repeatedly main-scanned in the direction of arrow C.

On the other hand, the synchronization light beam 5 transmitted through the half mirror 9
The light A enters the synchronizing signal generating condensing bar 1 of the present invention, which is arranged at a position conjugate with the object to be scanned 10 and the half mirror 9.

As shown in FIG. 2, when the synchronizing light beam 5A+ is incident on the light diffusing part 2, the incident light beam is diffused by the light diffusing part 2 and enters the condenser bar. The light enters the light-receiving element 3, such as a photodiode, provided on the end face of the converging bar while being totally reflected.

On the other hand, if the synchronizing light beam 5A2 deviates from the light diffusing portion 2 and enters the condenser bar, the light does not enter the light receiving element 3.

Since the portion that diffuses this light is formed in a lattice shape with a pitch corresponding to the pixels, the amount of light incident on the light receiving element 3 changes periodically with the main scanning of the scanning light beam 5B. Change. Therefore, the light receiving element 3 detects periodic changes in the synchronizing light beam 5A, 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.

The synchronization signal thus obtained is similar to the synchronization signal obtained from a conventional optical beam scanning device in which a grid 11 is provided in front of a condensing bar 12, as illustrated in FIG.

That is, in the conventional light beam device, a grid 11 in which a lattice is formed by chromium vapor deposition or the like at a pitch corresponding to the pixels is arranged at a position conjugate to the scanned object 1o and the half mirror 9, and behind it is a light condensing bar 12 having a light diffusion zone 12a for diffusing light on the surface opposite to the grid 11;
is provided. In this case, the synchronizing light beam 5A that has passed through the grid 11 is diffused by the light diffusion 'ttF 12 a of the condensing bar 12 provided behind the grid 11, and is totally reflected inside the condensing bar 12 and focused. light bar 12
The light enters the light receiving element 3 provided at the end of the light.

The amount of light detected by this light-receiving element 3 changes periodically due to the grating of the grid 11 as the scanning light beam 5B main scans in the C direction. There is no difference from using a light bar.

In the embodiment described above, the light beam 5 emitted from the laser light source 4 is deflected by the rotating polygon mirror 7, passes through the scanning lens 8, and is then divided into the scanning light beam 5B and the synchronization light beam 5A by the half mirror 9. However, the light beam 5 may be split before being incident on the rotating polygon mirror 7 and each beam may be incident on separate reflecting surfaces of the rotating polygon mirror 7. 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 wavelengths of the scanning light beam and the synchronization light beam are different, 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.

Furthermore, in the above embodiment, the light diffusing portion 2 formed on the surface of the light collecting bar is shaped like a grid with a pitch corresponding to the pixels, but the light collecting bar for synchronizing signal generation of the present invention can be adjusted according to its use. It can be widely applied and used by making the shape and spacing of the light diffusing part appropriate.

For example, it can be used as a control signal generating means for sub-scanning to feed the object 10 to be scanned at a predetermined speed in the direction B, or for starting point control to control the starting point of scanning.

<Effects of the Invention> According to the present invention, in a synchronization signal generation device used in a light beam scanning device, etc., it is possible to maintain the performance of the synchronization signal generation device and eliminate the need for a grid that was conventionally required. Can be done.

This eliminates the expense of manufacturing expensive grids and
It becomes possible to economically manufacture a light beam scanning device.

Further, it is possible to easily adjust the light beam scanning device.

[Brief explanation of the drawing]

FIG. 1 is a perspective view conceptually showing an embodiment of a light beam scanning device incorporating a condensing bar for synchronizing signal generation according to the present invention. FIG. 2 is an explanatory diagram for explaining the function of the synchronization signal generation condensing bar of the present invention. FIG. 3 is a perspective view schematically showing a conventional light beam scanning device. Explanation of symbols 1: Focusing bar for synchronizing signal generation, 2: Part that diffuses light, 3: Light receiving element, 4: Laser light source, 5th - light beam, 5A...Light beam for synchronization, 5B...Light beam for scanning, 6--Beam expander, 7...Rotating polygon mirror, 8...Scanning lens, No. 911, half mirror -1 10...Object to be scanned, 11. Thorn lid, 121. Fist condensing bar, 12a... Light diffusion zone FIG, 1

Claims (1)

[Claims] (1) A condensing bar made of a transparent material that propagates a light beam incident from the side toward its end surface along its longitudinal direction, and has a predetermined shape on the surface of the condensing bar in the longitudinal direction of the condensing bar. 1. A condensing bar for synchronizing signal generation, characterized in that it has portions formed at intervals of , for diffusing incident light.