JPS6279411A - Optical writing printer - Google Patents

Abstract

PURPOSE:To perform high-speed operation over a wide wavelength range by providing a light quantity control element which controls the transmission and cutoff of irradiated light by deforming a movable thin film with electrostatic force between charges in the movable thin film and a peripheral electric field under a vacuum. CONSTITUTION:When a switch 105 is set at a side A, the movable thin film 101 and a reverse surface electrode plate 103 are held at the same potential, a potential difference is generated between the movable thin film 101 and a top surface electrode plate 102, and the movable thin film 101 flexes to deform and enter a state 101. At this time, light 106 incident on the light quantity control element from a light source in a direction C reaches a convergence part 107 in a direction D almost without being cut off by the movable thin film 101 and the quantity of light used for optical writing is maximum. Then when the switch 105 is changed over to a side B, attractive force between the movable thin film 101 and reverse surface electrode plate 103 operates thin time and the movable thin film 101 returns to a state 201. At this time, the reflected light 106 is cut off by the movable thin film and never reaches the light convergence part 107. The space 110 where the thin film 101 is held under a vacuum, so the atmospheric pressure which operates on the thin film 101 is removed, so that the thin film is easily peeled off the electrode plate 103.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printer device that performs writing by exposing a photoreceptor or photosensitive paper using light. More specifically, the present invention relates to an optical writing head having a light amount control element that modulates the amount of light emitted from a light source.

[Prior Art] As an exposure method used in an optical writing printer, for example, a method in which light from a point light source such as a laser is focused and exposed by scanning a photoreceptor with a rotating polygon mirror or the like requires a complex and highly accurate optical system and control system. Requires. On the other hand, in a method that uses a linear light source and exposes the photoreceptor by controlling the amount of light with a light amount control element interposed between the light source and the photoreceptor, a light shutter array that integrates a large number of light amount control elements is mounted on the photoreceptor. By arranging them in close proximity, there is no need for a complicated optical system or control system, and a general light source such as a fluorescent lamp can be used as a light source, which has the advantage that the device can be realized with a simple configuration.

Conventionally, a liquid crystal shutter is used as the light amount control element,
One was used that selectively exposed the photoreceptor by transmitting or blocking light depending on whether the liquid crystal element was turned on or off. However, with this conventional technology, the response speed of the liquid crystal shutter is slow, the on/off light ratio of the shutter cannot be large, and the wavelength range of light that can be used is narrow due to the light absorption characteristics and light resistance of the liquid crystal material. However, it has disadvantages such as being controlled.

[Problems to be Solved by the Invention] The purpose of the present invention is to solve these problems, to be usable in a wide wavelength range, to be applicable to various light sources and photoreceptors, and to have a large light intensity ratio between on and off states. The object of the present invention is to realize an optical writing printer having a light amount control element capable of high-speed operation.

[Means for solving the problem] The optical writing printer of the present invention includes a movable thin film whose part is fixed to a substrate and whose other part is movable, and an electric field generation mechanism that generates an electric field around the thin film. , an electric current I application a structure for imparting an electric charge to the movable thin film, and the above-mentioned possible! ! The mechanism for irradiating the t7j thin film with light is comprised of a light amount configured to change the transmission/blocking of the irradiated light by bending and deforming the t7j thin film in vacuum in response to the electrostatic force caused by the electric field. It is characterized by having a control element.

[Operation] According to the above configuration of the present invention, the electrostatic force generated in the movable thin film 1 is reduced by controlling one or both of the mechanism for storing charge in the movable thin film and the mechanism for generating an electric field around the movable thin film. changes, and the amount of deflection deformation of the movable thin film changes accordingly. By changing the amount of deflection deformation of the movable thin film, the amount of transmitted light can be controlled by blocking the light irradiated by the light irradiation mechanism or transmitting it without blocking it.

The present invention uses the above-mentioned light amount control element to age the light onto the photoreceptor.

[Example] The present invention will be explained based on examples.

FIG. 1 is a sectional view showing an embodiment of a printer according to the present invention, in which light from a light source 1 is focused by a condensing lens 2 and irradiated onto a light amount control element 3. The light amount control element 3 controls the amount of transmitted light 1-1 The light focused by the imaging lens 4 exposes one point on the photoreceptor 5. In this way, the photoreceptor or the optical writing system is moved while performing optical writing. The surface of the photoreceptor is then scanned.

Figure 2 shows an example in which a line printer is constructed using a light quantity control element array in which a large number of light quantity control elements are integrated in a line.The light from a fluorescent lamp 11 is condensed by a condensing lens 12 to control the light quantity. A SELFOC lens array 14 is used as an imaging lens to irradiate the element array 13 and condense and image the transmitted light to form an image on the photoreceptor 5 for optical writing. By moving the photoreceptor 5 in the direction of the arrow, optical writing is performed on the entire plane.

For example, when photosensitive paper is used as the photoreceptor in Figures 1 and 2, processing such as development and fixing may be required, and when a photosensitive charging drum is used as the photoreceptor, electrostatic When a latent image is formed, steps such as development, transfer, and fixing using a well-known electrophotographic method are required, but since the present invention relates to the optical writing section, illustrations and explanations of the entire device will be omitted. .

Next, a light amount control element according to the present invention will be explained. Third
The figure is a sectional view showing an example of a light amount control element used in the present invention. The upper electrode plate 102 is formed by forming Nesa's transparent conductive film as an electrode on the upper surface of a glass substrate, and the lower electrode plate 1
03, a transparent conductive film made by Nesa was formed as an electrode on the lower surface of a glass substrate. A movable thin gold film 101 is formed on the lower electrode plate 103 with one end bonded via an adhesive layer 104 made of chromium, and a spacer 10 is also formed on the bottom electrode plate 103.
The space 110 in which the movable thin film 101 exists, with the upper electrode plate 102 sandwiching the electrodes 8 and 109, is in a vacuum state of less than 1 atm and is sealed with a glass substrate, a spacer, etc. A voltage is applied between the upper electrode plate 102 and the lower electrode plate 103 through a power source, forming a mechanism for generating an electric field around the movable thin film 101.

Next, the light amount control operation will be explained. When the switch 105 is switched to the A side in the figure, the movable thin plate 11!101 and the lower electrode plate 103 are at equal potential.・Although no electrostatic force is generated between them, a potential difference and capacitive coupling occur between the movable thin film 101 and the upper electrode plate 102, so there is a charge on the movable thin film 101 (negative charge in the case of the power configuration shown in the figure). ) is applied and accumulated, and an attractive force is generated between the upper electrode plate 102 and the upper electrode plate 102 due to electrostatic force.
Possible 2jJ thin film 101 is initially shown as 201 shown by a two-dot chain line in the figure.
What was in the state 101 in the figure is deflected and deformed. At this time, from the light source to the light amount control element C in the figure.
Almost all the light 106 incident from the direction is VJ thin film 101
The light condensing part 107 in the direction shown in the figure is unobstructed by
The amount of light used for light aging reaches its maximum. Next, when the switch 105 is switched to the B side in the figure, an attractive force due to electrostatic force is exerted between the movable thin film 101 and the lower electrode plate 103, and the movable thin film 101 is moved to the position 20 indicated by the two-dot chain line in the figure.
Return to state 1. At this time, most of the reflected light 106 is blocked by the movable thin film and is reflected, scattered, and absorbed, so that the amount of light reaching the condensing section 107 is minimized.

As shown above, by switching the potential of the movable thin film 101 using the switch 105 and deflecting and deforming the movable thin film 101, it is possible to control the amount of light that enters the light condensing section 107 and is used for optical writing. . In addition, if the switch 105 is connected to either the A side or the B side in the figure, and the movable thin film 101 is placed in a floating state, the charges stored before switching to the floating state are stored as they are, so the movable thin film 101 is placed in a floating state. The force generated on 101 does not change and has a memory effect that keeps it in the same position.

If the movable thin film 101 is sufficiently thin and flexible, the movable thin film 101 and the lower electrode plate 103 may come into close contact in the state 201 in FIG. 3. - When the carriers are in close contact with each other, the pressure of the surrounding gas is applied only to the upper surface of the movable thin film 101 and acts to press the movable thin film 101 against the lower electrode plate 103. If the space 110 is filled with the atmosphere, this pressure will be 10-'' in the case of complete contact.
kg f/-, and much larger force is required to peel off the movable thin film 101 than the force required to bend and deform the movable thin film 101 in the absence of adhesion or other influences. For example, in FIG.
．． Thickness of 109 d=0.05 (mm), movable thin film 1
01 thickness t=0.3 (μm), length of the movable part of the movable thin film 101 Ω; o.

15 (mm), and the state of 201 in Fig. 3 is the movable thin film 1.
In the initial state of 01, if the Y axis is in the direction of the top surface @ electrode plate 102 and the X axis is in the direction of length Ω, then the distance dx from the top electrode plate 102 at each X point of the movable thin film 101 is dx=d -Yx-t=d-Yx (','d'>t
), and when the applied voltage is V, the electrostatic force f acting on the 'minimal area ΔS on the movable thin film is f=cumulative, if the thickness of the glass portion of the upper electrode plate 102 is ignored. (Flea) It can be approximated as 2Δ5(1). On the other hand, the movable thin film 101 is cantilevered I□:
Assuming that the second moment of inertia of the cantilever beam is satisfied, the result of VA=125(v) is obtained for the tip of the movable thin film 101. On the other hand, if the movable thin film 101 is in complete contact with the lower electrode plate 103 and is pressed down at atmospheric pressure,
The voltage required to peel it off is VB (!, atmospheric pressure 0-Zkg f /J,!: L te, formula (1)
If we calculate numerically from ', we end up with a large value of VB -=8K (v). Movable thin H that overcomes atmospheric pressure
If A101 can be peeled off, it will no longer be affected by atmospheric pressure, so the applied voltage required to actually drive the movable thin film 101 in atmospheric pressure is the larger of VA and VB. If a method such as creating irregularities on the surface of the movable thin film 1010 is used, the adhesion force due to atmospheric pressure can be increased to 100
For example, if the space 110 is made into a vacuum state of 10-0-2 (at), the adhesion force will be reduced to 10-6 kg f/mn?, and from equation (1), vB , VB can be suppressed to 80 (v).Also, even if the surface of the movable thin film 101 is not made uneven, if it is evacuated to 10' (atm), vB can be suppressed to 80 (v). VB is 80 (v), which is also smaller than VA.Therefore, by keeping the space 110 in a vacuum state, the influence of atmospheric pressure on the applied voltage can be eliminated.

In this embodiment, the upper electrode plate 102 and the lower electrode plate 103 are made by forming a transparent conductive film on a glass substrate so as to transmit light. If so, the entire surface does not necessarily have to be transparent, so if windows are opened in these parts, it may be constructed of an opaque material such as a metal electrode plate with an insulating film formed of plastic or the like. , and the movable thin film 101
The material may be made of any conductive material with low light transmittance, or may have a composite structure of a conductor and a non-conductor.

When the material of the movable thin film 101 is changed, the material of the adhesive layer 104 is also changed accordingly, and may become unnecessary in some cases. Furthermore, in this embodiment, the light 106 from the light source enters from the direction C in the figure and reaches the condensing section 107 in the direction C, but this is because the light enters from the direction D and condenses in the direction C. It is also possible to construct a structure that reaches up to 100 mm.

In the embodiment shown in FIG. 3, only the switch 105 is replaced by a volume 43. as shown in FIG. If the movable thin film 101 is replaced with a
The deflection deformation position can also be arbitrarily set within the range of 10°1 to 201 in FIG. 3, and the amount of light incident on the light condensing section 107 can be continuously controlled.

Also, in the embodiment shown in FIG. 3, the switch 105 can be replaced as shown in FIGS. 5(a,) and (b)! 1iJ
The potential of the J thin film 101 may be fixed, and the potentials of the upper electrode plate 102 and the lower electrode plate 103 may be changed using a switch. The state of the movable thin film 101 is 101 in FIG. 3 when the switch is in the state shown in FIG. 5(a), and 101 in FIG.
In the state b), the state is as shown in 201 in FIG.

Note that the switches and volumes shown in FIGS. 3 to 5 are not limited to mechanical types, but may be solid-state types using semiconductors or the like.

FIG. 6 is a cross-sectional view of another embodiment of the light amount control element of the present invention, in which the upper surface electrode 102 and the lower surface electrode 103 are not parallel planes, but the distance is small near the base of the movable thin film 101, and the distance between the upper surface electrode 102 and the lower surface electrode 103 is small near the base of the movable thin film 101, and The point is that the space is configured so that the distance becomes wider as you go,
There is no adhesive layer and the movable thin film 10 is attached from the top surface with a spacer 108.
The only difference from the embodiment shown in FIG. 3 is that 1 is pressed and fixed, and the meanings and operations of the figure numbers are the same. Compared to the embodiment shown in FIG. 3, the electrostatic force when pulling the movable thin film 101 upward is increased, contributing to increased speed and efficiency.

Furthermore, when the movable thin film 101 is pulled upward or downward, its position remains stable as it comes into contact with the upper or lower electrode plates 102 and 103, so even when a large number of light quantity control elements are integrated. Products with uniform characteristics can be obtained with little variation. Further, in this embodiment, since the incident light 106 does not pass through the upper electrode plate 102, the upper electrode plate may be made of an opaque material. FIG. 7 shows still another embodiment of the light amount control element of the present invention. The embodiment shown in FIG. 3 is different from the embodiment shown in FIG. 3 in that the vacuum state is maintained by sealing all of them in a vacuum chamber 111 instead of sealing them with the upper electrode plate 102, lower electrode plate 103, and spacers 108 and 109. The points are different. In this case, spacer 109 becomes unnecessary. Other materials, operating principles, meanings of figure numbers, etc. are the same as those of the embodiment shown in FIG.

Of course, the light amount control element shown in FIG. 6 can also be constructed using a vacuum chamber 111 instead of the spacer 109.

[Effects of the Invention] In the light amount control element used in the present invention as shown in the above-mentioned embodiments, the flexible IJJ thin film moves mechanically to block or transmit light, so that the maximum/minimum light amount ratio is A large amount of light can be obtained, the loss caused by passing through a light amount control element is minimal, and it can be used for light of any wavelength, and does not impose any control on the photoreceptor or light source.

In addition, since the movable thin film is configured to flex in response to electrostatic attraction in both the vertical and vertical directions, compared to a method in which the attractive force is applied only in one direction and the movable thin film returns to its original position in the opposite direction using only the elastic force of the movable thin film. This makes it possible to drive at significantly higher speeds. At this time, since the movable thin film is configured to move in a vacuum, a decrease in response speed due to air resistance can be suppressed. Also, it can be caused by humidity! It is also possible to prevent the fJ thin film from adhering to the substrate. Note that when a soft material such as gold is used as the movable thin film, adhesion between the substrate and the movable thin film may pose a problem. At this time, if the movable thin film was in the atmosphere, a large electrostatic force equivalent to atmospheric pressure would be required to peel it from the substrate, but by driving it in a vacuum, the electrostatic force for peeling is reduced. As a result, the voltage applied to the circuit can be kept low.

In addition, since the movable thin film is driven by electrostatic force, almost no current flows and ultra-low power consumption can be achieved.
By making the T film floating, it has a memory effect that retains the previous state, so even when a large number of light amount control elements are integrated, dynamic driving by time division is easy and the number of driving drivers can be reduced. Further, since the light amount control element of the present invention can be manufactured using the same film-forming technology and patterning/etching technology as in semiconductor manufacturing processes, it is easy to manufacture a large number of integrated elements with high precision.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a preferred embodiment of the exposure section of the optical writing printer of the present invention. FIG. 2 is a diagram showing an embodiment in which a large number of light amount control elements are integrated. FIG. 3 is a diagram showing one embodiment of a light amount control element used in the present invention. FIG. 4 is a diagram showing another embodiment of the switch 105 in FIG. 3. 5(a) and 5(b) show the switch 10 in FIG.
FIGS. 5A and 5B are diagrams illustrating still another embodiment of No. 5, and FIGS. 5A and 5B show two states in which the switch is switched. FIGS. 6 and 7 are cross-sectional views showing other embodiments of the light amount control element used in the present invention. 3...Light amount control element 13...Light amount control element array 101...Movable thin film Fig. 4 (α) (b) Fig. 5 Fig. 6

Claims (1)

[Claims] A movable thin film having a part fixed to a substrate and the other part movable, a mechanism for generating an electric field around the movable thin film, a mechanism for applying an electric charge to the movable thin film, and irradiating light to the movable thin film. In a vacuum, the movable thin film deforms due to the electrostatic force between the charges in the movable thin film and the surrounding electric field, thereby causing the transmission of light irradiated to the movable thin film.
An optical writing printer comprising a light amount control element configured to control interruption.