JPH08118726A - Optical writer for light emitting element array printer - Google Patents

Abstract

PURPOSE: To print by a light emitting element array head having low resolution with high resolution by focusing and exposing at a position opposed to a light emitting element on a photosensibive medium between a lens and the medium, and electrically selecting the deviation of the focused position by a specific interval in the main scanning direction of an optical printer and the exposure of the position. CONSTITUTION: A plurality of light emitting elements are arranged at an interval of Nμm on a light emitting element array head 1, and a photosensitive medium 4 is formed oppositely to the head 1. A lens 2 is disposed between the head 1 and the medium 4, and focused position control means 3 for focusing and exposing at the position opposed to the element on the medium 4 to deviate the focused position by N/2μm in the main scanning direction of an optical printer to expose it is disposed between the lens 2 and the medium 4. Thus, even if the head 1 having low resolution is used, it can be printed with high resolution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting element array printer, and more particularly to an optical writing device for the light emitting element array printer.

[0002]

2. Description of the Related Art Conventionally, techniques in such a field include:
For example, White Series NO. 6 "Optical Printer Design" Trikeps Planning Department There were some as shown in P114 to P129. Generally, in an electrophotographic light emitting element array printer, a laser is used as a light source,
An LED element, a liquid crystal element, and the like are used, and a photosensitive drum uniformly charged by a charger is irradiated with the light source and exposed to form an electrostatic latent image. This electrostatic latent image is then developed by a developing device to become a toner image, and this toner image is transferred to paper by a transfer device and fixed by a fixing device.

LED of the light emitting element array printer
The printer uses an LED element as a light source. FIG. 11 is a schematic view of such a conventional LED printer. In the figure, 11 is a photosensitive drum, and 12 is a photosensitive drum 1.
1 is a charger for charging 1; 13 is an LED array head for exposing the photosensitive drum 11 to form an electrostatic latent image; 14 is a developing for developing the electrostatic latent image on the photosensitive drum 11 to form a toner image A device, 15 is a transfer device for transferring the toner image onto the sheet 16, 17 is a fixing device for fixing the transferred toner image, 18
Is a cleaner for removing the toner remaining on the photoconductor drum 11, 19 is a discharge lamp for removing the electric charge remaining on the photoconductor drum 11, 20 is a paper cassette, and 21 is a paper stacker.

When the LED elements of the LED array head 13 selectively perform one light emission operation, an electrostatic latent image is formed on the photosensitive drum 11 uniformly charged by the charger 12, and the developing device 14 The toner adheres to the photosensitive drum 11 according to the electrostatic latent image. On the other hand, paper cassette 2
The paper 16 supplied from 0 passes between the photoconductor drum 11 and the transfer device 15. At this time, the toner attached to the photoconductor drum 11 is transferred to the paper 16 by the transfer device 15,
After that, the sheet stacker 2 is fixed by the fixing device 17.
It is stored in 1.

On the other hand, in the photoconductor drum 11, the cleaning device 18 removes the toner remaining on the photoconductor drum 11, and the charge eliminating lamp 19 removes the electrostatic latent image formed in the previous electrophotographic process. It is removed and prepared for each process after the next charging process. A DC motor or an AC motor is used as a driving unit for rotating the photosensitive drum 11 at a constant speed and a driving unit for feeding paper.

FIG. 12 is an enlarged perspective view of an optical image forming system of a conventional light emitting element array printer, and FIG. 13 is a conceptual diagram of an optical image forming system of a conventional light emitting element array printer. In the figure, 13 is an LED array head in which a plurality of (for example, 128) LED array chips 31 are arranged, and 32 is a rod lens array in which a plurality of gradient index lenses are arranged. The rod lens array 32 forms an image of the light L of the LED array chip 31 on the photosensitive drum 11, which is a surface to be illuminated, at an equal magnification.

In this case, the resolution of the LED array head 13 and the resolution of the electrostatic latent image on the photosensitive drum 11, that is, the resolution of the printed image are the same. The resolution of the LED array head 13 is generally 240 DPI (dot per inch), 300 DPI, 400 DPI, 600 DPI.
When the resolution is large, for example, an image having a curved line can be printed faithfully on the original image.

In the driving unit, the print data output unit 36 outputs the print data and the driving signal to the LED driving unit 37, and the LED driving unit 37 converts the print data and the driving signal into the LED driving signal. It is being sent to the array head 13. FIG. 14 is a plan view of a conventional LED array head. In the figure, 39 is a substrate, and this substrate 39 has a wiring pattern (not shown) formed by thick film or thin film printing or the like. Reference numeral 31 is an LED array chip provided with a plurality of LED elements (not shown) in a row, and a plurality of LED array chips 31 are arranged on a substrate 39. As a result, the LED elements are arranged linearly along the longitudinal direction of the substrate 39 and at equal pitches.

Reference numeral 40 denotes a drive circuit chip (hereinafter referred to as a driver IC) for driving an LED element. The driver IC 40 is provided for each LED array chip 31 one by one. Reference numeral 41 is a wire that electrically connects the LED array chip 31 and the driver IC 40. FIG. 15 is a diagram showing a light emitting portion of a conventional LED array chip.

In the figure, 31 is an LED array chip,
Reference numeral 44 denotes a light emitting area, which is arranged at a pitch of 42.3 μm, for example. Reference numeral 45 is an individual electrode connected to the light emitting area 44. The individual electrode 45 is connected to the driver IC 40 (FIG. 14) by the wire 41.
By supplying a print data signal to the driver IC 40, the LED array head 13 can obtain a desired light emission pattern. The light emitting portion of the LED array head 13 is formed by arranging a plurality of LED array chips 31 in a line.

FIG. 16 is a perspective view showing a boundary portion of a conventional LED array chip. In the figure, 31 is an LED array chip, 44 is a light emitting area, 45 is an individual electrode, and 48 is a connection space. At the boundary of each LED array chip 31, the distance between the end of the light emitting area 44 and the end of the LED array chip 31 is 8 μm.
The distance between them, that is, the connection space 48 is 6.3 μm.

[0012]

However, in the conventional light emitting element array printer, the accuracy of the distance between the light emitting areas 44 and the distance between the end of the light emitting area 44 and the end of the LED array chip 31 and the LED array. Chip 31
It is difficult to increase the accuracy of the external dimensions of
The array chip 31 cannot be accurately arranged in a line. Moreover, since there are many connection points between the LED array chip 31 and the driver IC 40, the yield is low and the cost is high.

To increase the resolution of the printed image,
The resolution of the LED array head 13 must be increased. For example, in order to manufacture the LED array head 13 of 600 DPI or more, the light emitting area 44 and the LED array chip 31 must be downsized, and the mounting technique such as wire bonding with the wires 41 must be made high in density.
The cost will be high.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above problems and provide an optical writing device for a light emitting element array printer which can print at a high resolution even when a light emitting element array head having a low resolution is used. .

[0015]

In order to achieve the above object, the present invention provides [1] a light emitting element array head in which a plurality of light emitting elements are arranged at intervals of N μm, and a light emitting element array head facing the light emitting element array head. Is disposed between the light-emitting element array head and the photosensitive medium to form an electrostatic latent image by receiving light emitted from the light-emitting element, and focuses the light emitted from the light-emitting element. In the optical writing device of the light emitting element array printer having a lens for forming an image on the photosensitive medium, the lens (2,
102) and the photosensitive medium (4, 104) to form an image at a position facing the light emitting element on the photosensitive medium for exposure, and to shift the image forming position by N / 2 μm in the main scanning direction of the optical printer. The image forming position control means (3, 61, 103) having a function of electrically selecting exposure is arranged.

[2] In the optical writing device for a light emitting element printer according to the above [1], the image forming position control means (3, 61, 103) emits light from the light emitting element in the order of the writing light path from the light emitting element side. A polarizing plate (5) for converting the polarized light into linearly polarized light, and transmitting the incident linearly polarized light without changing the polarization direction, depending on the polarity of the applied electric signal,
Ferroelectric liquid crystal cell (50,
150), the incident surface is set at a predetermined angle with respect to the optical axis and has a predetermined thickness, and the component of the incident light in the optical axis direction is transmitted by being displaced by N / 2 μm in the main scanning direction of the optical printer. , The birefringent plate (52, 1,
52) is connected and arranged.

[3] In the optical writing device for a light emitting element printer according to the above [1], the image forming position control means (3) controls the light emitted from the light emitting element in the writing light path order from the light emitting element side. Polarizing plate for linearly polarized light (5)
And one glass substrate (8) with a transparent electrode (6) and another glass substrate (9) with a transparent electrode (7) are subjected to an alignment treatment, and each transparent electrode (6, 7) ), And a ferroelectric liquid crystal cell sandwiching a ferroelectric liquid crystal (50)
With the light incident surface set at a predetermined angle with respect to the optical axis and having a predetermined thickness, the optical axis direction component of the incident light is transmitted by being displaced by N / 2 μm in the main scanning direction of the optical printer. The birefringent plate (52) that allows the component orthogonal to the optical axis to pass therethrough is connected and arranged.

[4] In the optical writing device of the light emitting element printer according to the above [1], the image forming position control means (6
1) is a polarizing plate (5) for linearly polarizing the light emitted from the light emitting element in the order of the writing light path from the light emitting element side;
The glass substrate (8) with the transparent electrode (6) and the birefringent substrate (156) with the transparent electrode (7) are subjected to an alignment treatment to form the transparent electrodes (6, 7). Ferroelectric liquid crystal cells (50) sandwiching the ferroelectric liquid crystal in opposition to each other are connected and arranged. The birefringent substrate (156) has an incident surface set at a predetermined angle with respect to the optical axis and has a predetermined thickness, and the optical axis direction component of the incident light is N / 2 μm in the main scanning direction of the optical printer. The component is displaced and transmitted, and the component orthogonal to the optical axis is transmitted as it is.

[5] In the optical writing device of the light emitting element printer according to the above [1], the image forming position control means (1
03) sets the incident surface at a predetermined angle with respect to the optical axis in the order of the writing light path from the light emitting element side, has a predetermined thickness, and the optical axis direction component of the incident light is the main scanning of the optical printer. The birefringent plate (152) that displaces by N / 2 μm in the direction and transmits, and the component that is orthogonal to the optical axis as it is, one glass substrate (111) with a transparent electrode (106), and another transparent plate. A ferroelectric liquid crystal cell (150) in which a glass substrate (108) with an electrode (107) is subjected to an alignment treatment, respective transparent electrodes (106, 107) are opposed to each other, and a ferroelectric liquid crystal (110) is sandwiched. And the polarizing plate (105) are connected and arranged.

[6] In the optical writing device of the light emitting element printer according to the above [1], the image forming position control means (1
03) is a birefringent substrate (156) with a transparent electrode (106), in the order of the writing light path from the light emitting element side;
A glass substrate (108) with a transparent electrode (107) is subjected to an alignment treatment, and each transparent electrode (106, 1)
07) are opposed to each other, and the ferroelectric liquid crystal cell (150) sandwiching the ferroelectric liquid crystal and the polarizing plate (105) are connected and arranged. Birefringent substrate (15
6) has an incident surface set at a predetermined angle with respect to the optical axis and has a predetermined thickness, and the component of the incident light in the optical axis direction is displaced by N / 2 μm in the main scanning direction of the optical printer and transmitted. It is the one.

[7] A light-emitting element array head in which a plurality of light-emitting elements are arranged at N μm intervals, and a light-emitting element array head which is arranged so as to face the light-emitting element array head, receives light emitted from the light-emitting elements, and electrostatically Light of a light emitting element array printer having a photosensitive medium that forms a latent image and a lens that is disposed between the light emitting element array head and the photosensitive medium and focuses light emitted from the light emitting element to form an image on the photosensitive medium. In the writing device, an image is exposed between the light emitting element array head (1, 101) and the lens (2, 102) at a position facing a light emitting element on a photosensitive medium, and the image forming position is exposed. The above-mentioned [2] having a function capable of electrically selecting exposure by shifting by N / 2 μm in the main scanning direction of the optical printer.
The image forming position control means (3, 61, 103) described in [3], [4], [5] or [6] is arranged.

[8] A light emitting element array head in which a plurality of light emitting elements are arranged at intervals of N μm, and a light emitting element array head which is arranged so as to face the light emitting element array head, receives light emitted from the light emitting elements, and electrostatically Light of a light emitting element array printer having a photosensitive medium that forms a latent image and a lens that is disposed between the light emitting element array head and the photosensitive medium and focuses light emitted from the light emitting element to form an image on the photosensitive medium. In the writing device, a polarizing plate (5) for converting light emitted from the light emitting element into linearly polarized light, a focusing lens (2), and one transparent electrode (6) in the order of the writing light path from the light emitting element side. A glass substrate (8) with a transparent electrode and another glass substrate (9) with a transparent electrode (7) are subjected to an alignment treatment, and the transparent electrodes (6, 7) are opposed to each other to sandwich the ferroelectric liquid crystal. Ferroelectric liquid crystal cell (50) and optical axis On the other hand, the light incident surface is set at a predetermined angle and has a predetermined thickness. The component of the incident light in the optical axis direction is displaced by N / 2 μm in the main scanning direction of the optical printer and transmitted, and is orthogonal to the optical axis. The component to be used is arranged by connecting the birefringent plates (52) which are transparent as they are.

[0023]

[9] A light-emitting element array head in which a plurality of light-emitting elements are arranged at N μm intervals, and a light-emitting element array head that is arranged so as to face the light-emitting element array head, receives light emitted from the light-emitting elements, and forms an electrostatic latent image. In an optical writing device of a light emitting element array printer, which has a photosensitive medium to be formed and a lens which is arranged between the light emitting element array head and the photosensitive medium, and which focuses light emitted from the light emitting element to form an image on the photosensitive medium. , A polarizing plate (5) for linearly polarizing the light emitted from the light emitting element in the order of the writing light path from the light emitting element side, a glass substrate (8) with one transparent electrode (6) and another A ferroelectric liquid crystal cell (50) in which a glass substrate (9) with a transparent electrode (7) is subjected to an alignment treatment, and the transparent electrodes (6, 7) are opposed to each other to sandwich a ferroelectric liquid crystal, and focusing is performed. Lens (2) with a certain property, and predetermined for the optical axis The incident surface is set at an angle and has a predetermined thickness. The component of the incident light in the optical axis direction is displaced by N / 2 μm in the main scanning direction of the optical printer and is transmitted, while the component orthogonal to the optical axis is transmitted as it is. The birefringent plates (52) are connected and arranged.

[10] A light emitting element array head in which a plurality of light emitting elements are arranged at intervals of N μm, and a light emitting element array head which is arranged so as to face the light emitting element array head, receives light emitted from the light emitting elements, and electrostatically Light of a light emitting element array printer having a photosensitive medium that forms a latent image and a lens that is disposed between the light emitting element array head and the photosensitive medium and focuses light emitted from the light emitting element to form an image on the photosensitive medium. In the writing device,
A polarizing plate (5) for linearly polarizing the light emitted from the light emitting element, a converging lens (2), and a glass substrate with one transparent electrode (6) in the order of the writing light path from the light emitting element side ( 8) and a birefringent substrate (15) with a transparent electrode (7)
6) is subjected to orientation treatment, and each transparent electrode (6,
7) are opposed to each other and are arranged so as to be connected to a ferroelectric liquid crystal cell (50) sandwiching a ferroelectric liquid crystal. The birefringent substrate (156) has an incident surface set at a predetermined angle with respect to the optical axis and has a predetermined thickness, and the optical axis direction component of the incident light is displaced by N / 2 μm in the main scanning direction of the optical printer. Then, the component orthogonal to the optical axis is transmitted as it is.

[11] A light emitting element array head in which a plurality of light emitting elements are arranged at intervals of N μm, and a light emitting element array head which is arranged so as to face the light emitting element array head, receives light emitted from the light emitting elements, and electrostatically Light of a light emitting element array printer having a photosensitive medium that forms a latent image and a lens that is disposed between the light emitting element array head and the photosensitive medium and focuses light emitted from the light emitting element to form an image on the photosensitive medium. In the writing device,
The incident surface is set at a predetermined angle with respect to the optical axis in the order of the writing light path from the light emitting element side, has a predetermined thickness, and the optical axis direction component of the incident light is N / N in the main scanning direction of the optical printer. 2 μm
A birefringent plate (152) that displaces and transmits light, and a component that is orthogonal to the optical axis as it is, and a converging lens (102).
And a glass substrate (11) with a transparent electrode (106).
1) and another glass substrate (108) with a transparent electrode (107) are subjected to an alignment treatment, and the transparent electrodes (106, 107) are made to face each other, and a ferroelectric liquid crystal is sandwiched between them. Dielectric liquid crystal cell (150) and polarizing plate (105)
And are connected and arranged.

[12] A light-emitting element array head in which a plurality of light-emitting elements are arranged at N μm intervals, and a light-emitting element array head which is arranged so as to face the light-emitting element array head, receives light emitted from the light-emitting elements, and electrostatically Light of a light emitting element array printer having a photosensitive medium that forms a latent image and a lens that is disposed between the light emitting element array head and the photosensitive medium and focuses light emitted from the light emitting element to form an image on the photosensitive medium. In the writing device,
The incident surface is set at a predetermined angle with respect to the optical axis in the order of the writing light path from the light emitting element side, has a predetermined thickness, and the optical axis direction component of the incident light is N / N in the main scanning direction of the optical printer. 2 μm
A birefringent plate (152) that displaces and transmits, and a component that is orthogonal to the optical axis as it is, and one transparent electrode (106).
Attached glass substrate (111) and another transparent electrode (10
7) The glass substrate (108) with the film is subjected to orientation treatment,
Face each transparent electrode (106, 107),
Ferroelectric liquid crystal cell sandwiching ferroelectric liquid crystal (105)
And the converging lens (102) and the polarizing plate (105) are connected to each other.

[13] A light-emitting element array head in which a plurality of light-emitting elements are arranged at N μm intervals, and a light-emitting element array head which is arranged so as to face the light-emitting element array head, receives light emitted by the light-emitting elements, and electrostatically Light of a light emitting element array printer having a photosensitive medium that forms a latent image and a lens that is disposed between the light emitting element array head and the photosensitive medium and focuses light emitted from the light emitting element to form an image on the photosensitive medium. In the writing device,
An alignment treatment is applied to one birefringent substrate (156) with a transparent electrode (106) and one glass substrate (108) with a transparent electrode (107) in order of the writing light path from the light emitting element side. A ferroelectric liquid crystal cell (150) having a ferroelectric liquid crystal sandwiched between the transparent electrodes (106, 107), a focusing lens (102), and a polarizing plate (10).
5) is connected to and disposed. The birefringent substrate (156) has an incident surface set at a predetermined angle with respect to the optical axis and has a predetermined thickness, and the optical axis direction component of the incident light is displaced by N / 2 μm in the main scanning direction of the optical printer. It is made to be transparent.

[0028]

[Action]

[A]. [1], [2], [3], [5],
[7], [8],

According to the optical writing device of the light emitting element array printer as described in [9], [11] or [12], a light emitting element array head having a plurality of light emitting elements arranged at intervals of N μm, and the light emitting element array head Light emitted by the light-emitting element, which is disposed between the light-emitting element array head and the photosensitive medium, which is arranged facing each other and receives the light emitted by the light-emitting element to form an electrostatic latent image. In an optical writing device of a light emitting element array printer having a lens for focusing and forming an image on a photosensitive medium, a linearly polarized light that is incident on a polarizing plate is transmitted according to the polarity of an applied electric signal without changing the polarization direction. A ferroelectric liquid crystal cell that transmits through a 90 ° rotation, has an incident surface set at a predetermined angle with respect to the optical axis, has a predetermined thickness, and the optical axis direction component of the incident light is N / 2 μm displacement in the main scanning direction Of the birefringent plate that transmits the light and transmits the component orthogonal to the optical axis as it is. An image forming position control means having a function of electrically selecting exposure by shifting by N / 2 μm in the main scanning direction is provided.

Therefore, when the light emitting element array head performs the light emitting operation according to the odd number data of the print data for one line, the image forming position is not displaced and the light emitting element array head is moved to the position facing the light emitting element on the photosensitive medium. Exposure is performed by forming an image and shifting the image forming position in the main scanning direction of the optical printer by N / 2 μm when performing the light emitting operation of the light emitting element array head according to the even number data of the print data for one line. By doing so, by using the light emitting element array head in which the light emitting areas are arranged at a pitch of N μm in the main scanning direction, N / m in the main scanning direction is used.
Exposure and printing can be performed at a pitch of 2 μm, which enables printing with higher resolution.

[B]. [4], [6], [7],
According to the optical writing device for a light emitting element array printer described in [10] or [13], in addition to the above-described effects of [A], one glass substrate is omitted, and the optical system of the optical printer can be used for a short period of time. Can be arranged relatively easily. In addition, it is expected that loss such as interface reflection will be reduced.

[0031]

Embodiments of the present invention will be sequentially described below with reference to the drawings. FIG. 1 is a schematic view of an optical writing device of a light emitting element array printer showing a first embodiment of the present invention, and schematically shows its simple configuration and a writing light path. In the figure, an optical writing device of a light emitting element array printer comprises a light emitting element array 1, a converging rod lens array 2, an image forming position control means 3, a photosensitive drum 4 as a photosensitive medium, and the like, and changes the path of light L. The image forming position can be changed.

FIG. 2 is a view showing the arrangement of the image forming position control means in the optical writing device. A polarizing plate 5 having a transmission axis in a direction orthogonal to the main scanning direction, and two glass substrates 8 and 9 on which transparent electrodes 6 and 7 are formed on one surface and an alignment film (not shown) is formed, with a liquid crystal layer 10 interposed therebetween. A liquid crystal cell section 50 having a structure in which the orientation film and the surfaces on which the transparent electrodes 6 and 7 (for example, ITO electrodes) are formed face each other and are sealed;
A drive circuit 51 for applying an electric signal to the liquid crystal cell section 50.
And a birefringent plate 52.

3 to 4 are explanatory views showing the structure and operation of the liquid crystal cell portion in the image forming position control means. Here, in the liquid crystal cell portion 50, the liquid crystal layer 10 (FIG. 2) is a chiral smectic C phase. A ferroelectric liquid crystal having is used. FIG. 3 is a schematic diagram for explaining the switching of the ferroelectric liquid crystal. Ferroelectric liquid crystal has a spiral structure, but when sandwiched in a liquid crystal cell having a cell thickness thinner than the spiral pitch, the spiral structure is unraveled, and as shown in FIG. 3, the liquid crystal molecules 53 are aligned with the smectic layer normal line. Thus, it is possible to realize a state in which a region in which the inclination angle is −θ (here, θ = 22.5 °) is stable and a region in which the inclination angle is θ in the opposite direction and is stable is mixed.

In FIG. 3, W is the layer normal of the smectic phase, n is the major axis direction (director) of the liquid crystal molecules 53, and
The symbol ● in and the symbol + in ○ indicate the direction of spontaneous polarization. By applying an electric field in a direction perpendicular to the paper surface, the directions of the liquid crystal molecules 53 and their spontaneous polarization can be made uniform, and that state can be maintained. And
Switching between the two states can be performed by switching the polarity of the applied electric field. That is, FIG.
When an electric field of −E is applied to the state A tilted by −θ from the layer normal direction W of the smectic phase, when an electric field of + E is applied to the state A, θ from the layer normal direction W of the smectic phase.
45 degrees from the orientation state of state A
It can be stabilized in the tilted state B.

FIG. 4 is a schematic view showing the operation of a liquid crystal cell in which a ferroelectric liquid crystal is sealed. In the figure, the thickness d of the liquid crystal layer 10 is determined by the wavelength λ of the transmitted light L (for example, 720 nm) and the refractive index anisotropy Δn of the liquid crystal material at 720 nm so that Δn × d = λ / 2 is satisfied (that is, Determined so that the half-wave plate condition is satisfied).

In the polarizing plate 5 (FIG. 2), the transmission axis of the polarizing plate 5 is orthogonal to the main scanning direction of the optical printer, and the liquid crystal layer 1 is formed.
Of the two stable states of the liquid crystal molecule orientation at 0, the liquid crystal molecule 53 is set so as to coincide with the long axis direction of one of the stable states (here, the stable state A when an electric field of −E is applied). . The function of the liquid crystal cell unit 50 (FIG. 2) is to apply the polarization direction of the light L, which is transmitted through the polarizing plate 5 and is linearly polarized, to the transparent electrodes 6 and 7 (FIG. 2) of the liquid crystal cell unit 50. By switching the polarity of the electric field, switching between two states is performed and the polarization direction is changed. That is, when an electric field of −E is applied between the transparent electrodes 6 and 7, the liquid crystal molecules 53 are −θ from the layer normal direction W of the smectic phase.
The incident polarized state of light L is transmitted through the liquid crystal cell unit 50 while maintaining the polarization direction.

On the other hand, when an electric field of + E is applied to the transparent electrodes 6 and 7, the liquid crystal molecules 53 have an alignment state (stable state B) inclined by + θ from the layer normal direction W of the smectic phase. In this case, since θ = 22.5 °, the liquid crystal molecule long axis (director) is oriented at an angle of 2θ = 45 ° with respect to the incident polarized light. As a result, the half-wave plate condition is established, and the incident polarized light of the light L has a polarization direction of 90 while passing through the liquid crystal cell unit 50.
° Rotate.

FIG. 5 is an explanatory view showing the structure and function of the birefringent plate in the image forming position control means. In the figure, the birefringent plate 52 is a uniaxial crystal having optical anisotropy, for example, calcite, and the normal direction x of the birefringent plate 52 and the optical axis a are angle φ (where φ> 0 °). It was cut diagonally so that Here, the direction in which the optical axis a is projected on the surface of the birefringent plate 52 on the liquid crystal cell unit 50 side is the y axis, and the normal direction of the plane including the x axis and the y axis is the z axis.

Light L which is incident in the normal direction x of the birefringent plate 52
The transmission will be described. When the light L changes in the y-axis direction (that is, it has a polarization component in the optical axis a direction;
L1), the normal direction x of the birefringent plate 52 and the optical axis a
Within the plane (main cross section) including and, while passing through the birefringent plate 52, it is displaced by the distance S. When the light L is polarized in the z-axis direction (that is, when it has no polarization component in the optical axis a direction; L2), it is transmitted as it is.

The positional relationship between the birefringent plate 52 and the liquid crystal cell section 50 is -E between the transparent electrodes 6 and 7 of the liquid crystal cell section 50.
Liquid crystal molecules 53 in stable state A when an electric field of
And the y-axis of the birefringent plate 52 (the direction in which the optical axis a is projected on the surface of the birefringent plate on the liquid crystal cell section 50 side) are arranged so as to be orthogonal to each other. That is, the y-axis is set in the main scanning direction.

Next, the operation of the first embodiment of the present invention will be described. FIG. 6 is a light path diagram in the first embodiment of the present invention. FIG. 6A shows a case where an electric field of −E is applied to the liquid crystal cell to bring the liquid crystal molecules into the state A, and FIG. + E for liquid crystal cell
The case where the liquid crystal molecules are brought into the state B by applying the electric field of 2 is shown. Here, consider two light emitting areas of the LED array head. The light emitting area 44 (see FIG.
The pitch of 5) is, for example, 42.3 μm. The light L emitted from the light emitting area 44a passes through the condensing rod lens array 2 and enters the polarizing plate 5 of the image forming position control means. The light L passes through the polarizing plate 5 to be converted into linearly polarized light ● having a vibration direction in a direction orthogonal to the main scanning direction, and is incident on the liquid crystal cell unit 50. In the figure, ● indicates the polarization direction in the normal direction to the paper surface, and ← → indicates the polarization direction parallel to the paper surface.

Here, the case where a -E electric field is applied to the liquid crystal cell section 50 of the image forming position control means to orient the liquid crystal molecules in the stable state A will be described. Liquid crystal molecule 53 (Fig. 3)
Are uniformly oriented with the director in the same direction as the polarization direction of the light L, so that the light L passes without changing the polarization direction (polarization in the ● direction).

Next, the light L enters the birefringent plate 52. The birefringent plate 52 has the long axis direction of the liquid crystal molecules 53 in the stable state A when an electric field of −E is applied to the liquid crystal cell part 50 and the y axis of the birefringent plate 52 (the liquid crystal cell part 50 of the birefringent plate 50). The light L does not have a vibration component in the direction of the optical axis a because it is installed so as to be orthogonal to the direction in which the optical axis a is projected on the side surface). Therefore, the light L passes through kl without being displaced,
The dots 54a on the photosensitive drum 4 are irradiated.

Then, an electric field of + E is applied to the liquid crystal cell section 50 of the image forming position control means 3 to bring the liquid crystal molecules 53 into the stable state B.
The case of orienting the film will be described. The liquid crystal molecules 53 (FIG. 3) are uniformly oriented with their directors oriented in the direction of 2θ = 45 ° with respect to the polarization direction of the light L. The light L is decomposed into a vibration component in the director direction of the liquid crystal molecules 53 and a vibration component in a direction orthogonal to the director of the liquid crystal molecules 53, and passes through the liquid crystal layer 10. Since the liquid crystal layer 10 is designed to satisfy the half-wave plate condition at the wavelength λ (for example, 720 nm) of the incident light L, when leaving the liquid crystal layer 10, the component vibrating in the direction orthogonal to the director is
Half wavelength (phase π) from the component oscillating in the director direction
Only the phase is delayed. When leaving the liquid crystal layer 10, the two vibration components are combined. At this time, the polarization direction is rotated by 90 ° from the polarization direction of the incident light (polarization direction ← →) and emitted.

Next, the light L enters the birefringent plate 52.
Since the polarization direction is rotated by 90 ° in the liquid crystal cell unit 50 (← → direction) and is incident on the birefringent plate 52, the light L has a vibration component in the optical axis a direction. Therefore, the birefringent plate 52
In the plane (in the main cross section) including the normal direction x of X and the optical axis a, while passing through the birefringent plate 52, it is displaced by the distance S in the main scanning direction, and passes through k3 to form dots on the photosensitive drum 4. 55a is irradiated.

The displacement amount s can be expressed by the following equation (1). S = [[D (b ² −a ² )] / 2c ² ] sin2φ (1) where D: thickness of birefringent plate a = 1 / ne, b = 1 / none; light of birefringent plate Refractive index no in the axial direction; refractive index φ in the direction orthogonal to the optical axis; angle between the normal direction x of the birefringent plate and the optical axis a is c ² = a ² sin ² φ + b ² cos ² φ.

A case where calcite, which is a typical birefringent crystal, is used as the birefringent plate 52 will be described.
If the incident light wavelength is 720 nm, calcite 720 nm
The refractive indices at are ne = 1.65 and no = 1.48. At this time, the displacement amount S1 per 1 mm of the birefringent plate with respect to the angle φ formed by the optical axis a and the normal direction x of the birefringent plate is shown in FIG.
Can be expressed as

For example, when the angle φ between the optical axis a and the normal direction x of the birefringent plate is φ = 5 °, the thickness D (mm) of the birefringent plate.
And the displacement amount S (μm) have a proportional relationship as shown in FIG. Therefore, when the displacement amount S is set to 21.15 μm which is half the pitch 42.3 μm of the light emitting area 44 in the main scanning direction, for example, the angle φ = 5 ° formed by the optical axis a and the normal direction x of the birefringent plate. Then, the thickness D of the birefringent plate may be set to 1.24 mm.

From the above equation (1), the displacement amount S is proportional to the thickness D of the birefringent plate, and the proportional constant S1 is determined by the angle φ formed by the optical axis a and the normal direction x of the birefringent plate. You can Therefore, a desired displacement amount can be obtained by appropriately setting the angle φ formed by the optical axis a and the normal direction x of the birefringent plate and the thickness D of the birefringent plate. Therefore, 4
It is possible to irradiate the photosensitive drum with a resolution of 21.15 μm in the main scanning direction by using an LED array head having a resolution of 2.3 μm pitch.

The driving of the first embodiment of the present invention will be described. First, -E is applied to the liquid crystal cell unit 50 of the image forming position control means 3.
Is applied to uniformly orient the liquid crystal molecules 53 in the direction orthogonal to the main scanning direction (that is, to stabilize in the state A). Since the ferroelectric liquid crystal can maintain a stable state even if the electric field is removed, the electric field may be removed here.

The LED array head emits light in accordance with the odd number data of the print data for one line in the main scanning direction. At this time, since the light does not rotate the polarization, even if the light passes through the birefringent plate, the image forming position is not displaced. Then, an electric field of + E is applied to the liquid crystal cell unit 50 of the image forming position control means 3 to uniformly orient the liquid crystal molecules in a direction inclined by 45 ° from the state A in the main scanning direction (that is, state B). To stabilize).

The LED array head emits light in accordance with the even number data of the print data for one line in the main scanning direction. At this time, since the polarization direction of light is rotated by 90 °, the light is incident in the direction of the optical axis of the birefringent plate set in the main scanning direction.
Therefore, the image forming position is displaced in the main scanning direction and the photosensitive drum is irradiated. Complete the printing of one line in the main scanning direction,
The photosensitive drum is fed in the sub-scanning direction, and the printing operation for the next line is continued.

Therefore, using the optical writing device of the first embodiment of the present invention, an LED array head having a resolution of N μm, for example, 42.3 μm pitch is used, and N / 2 μm, for example, 21.15 μm in the main scanning direction. It is possible to irradiate on the photosensitive drum at a resolution and print. In this way, the light emitting element array head in which a plurality of light emitting elements are arranged at N μm intervals and the photosensitive medium are arranged facing the light emitting element array head, and the light emitting element array head and the photosensitive medium are arranged. In the optical writing device of the optical printer, in which a lens is arranged between the light emitting elements, the light emitted from the light emitting element is focused to form an electrostatic latent image on the photosensitive medium,
Between the light emitting element array head and the photosensitive medium, a polarizing plate,
An image forming position control means comprising three ferroelectric liquid crystal cells satisfying the half-wave plate condition and a birefringent plate having a surface normal at a predetermined angle with respect to the optical axis and having a predetermined thickness. Arranged. In the ferroelectric liquid crystal cell, the polarization direction of the transmitted light of the ferroelectric liquid crystal cell can be rotated by 90 ° by switching the polarity of the electric signal, and the polarization direction of the light incident on the birefringent plate is Parallel to the optical axis of the birefringent plate, or
It is possible to select whether to make the directions orthogonal to each other by the polarity of the electric signal.

If the polarization of the incident light is parallel to the optical axis direction, the birefringent plate can displace the optical path in the main scanning direction by a predetermined amount (here, N / 2 μm), If the polarization of the incident light is orthogonal to the optical axis direction, it can be transmitted without displacement. Therefore, when the light emitting operation of the LED array head is performed according to the odd number data of the print data for one line and when the light emitting operation of the LED array head is performed according to the even number data of the print data for one line, By switching the polarity of the electric signal applied to the liquid crystal cell of the image forming position control means, an LED array head having a resolution of N μm, for example, 42.3 μm pitch in the main scanning direction is used, and N / m in the main scanning direction is used.
It is possible to irradiate and print on the photosensitive drum with a resolution of 2 μm, for example, 21.15 μm.

Therefore, it is possible to print at a high resolution by using a low resolution light emitting element array printer. On the contrary, it becomes possible to print at a higher resolution by using a high resolution light emitting element array printer. Various combinations that give the same effects as those of the first embodiment can be considered. That is, in the first embodiment, the main scanning direction is aligned with the direction in which the optical axis of the birefringent plate is projected on the incident surface, and the alignment direction of the liquid crystal molecules when the electric field of −E is applied to the liquid crystal cell is mainly set. The embodiment is one in which the transmission axis of the polarizing plate is orthogonal to the scanning direction and the transmission axis of the polarizing plate is orthogonal to the main scanning direction.

However, there are various possible combinations of the transmission axis direction of the polarizing plate, the alignment direction of the liquid crystal layer, and the incident surface projection direction of the optical axis of the birefringent plate, which give the same effect. FIG. 9 shows an example of the combination. Here, the main scanning direction is made coincident with the direction in which the optical axis of the birefringent plate is projected on the incident surface. In the table, the combinations marked with ◯ are the combinations described in the examples of the present invention.

Therefore, other combinations than the installation directions described in the embodiments are not excluded from the scope of the present invention as long as the same effect can be obtained. Next, a second embodiment of the present invention will be briefly described. FIG. 10 is a schematic view of an optical writing device of a light emitting element array printer showing a second embodiment of the present invention, and schematically shows its simple configuration and the writing light path.

In the figure, an optical writing device of a light emitting element array printer has a light emitting element array 1, an image forming position control means 3, a converging rod lens array 2, and a photosensitive drum 4 as a photosensitive medium. The image forming position control means 3 for changing the image forming position by changing the path by dispersing L
It is installed between the light emitting element array 1 and the converging rod lens array 2. That is, in the above-described first embodiment, the image forming position control means is the focusing rod lens array 2
And the photosensitive drum 4 as a photosensitive medium, but in the second embodiment, it is arranged between the light emitting element array 1 and the converging rod lens array 2.

Regarding the operation, action and effect in this case,
Since it is the same as the first embodiment, it will be omitted. Next, a third embodiment of the present invention will be described. FIG. 17 is a diagram schematically showing a configuration of an optical writing device of a light emitting element array printer and a path of writing light according to a third embodiment of the present invention.
FIG. 19 is a diagram showing a configuration of an image forming position control means showing a third embodiment of the present invention, FIG. 19 is a light path diagram in the third embodiment of the present invention, and FIG. 19B shows the case where the liquid crystal molecules are in the state A, and FIG. 19B shows the case where the + E electric field is applied to the liquid crystal cell and the liquid crystal molecules are in the state B. The same parts as those in the first and second embodiments are designated by the same reference numerals and the description thereof is omitted.

In FIG. 17, an optical writing device of a light emitting element array printer has a light emitting element array 1, a converging rod lens array 2, an image forming position control means 61, and a photosensitive drum 4 as a photosensitive medium. The path of the writing light L can be changed to change the image forming position. The third embodiment is partially different from the first embodiment in the configuration of the image forming position control means 61. That is, as shown in FIGS. 18 and 19, in order from the light emitting element side, the polarizing plate 5 and one glass substrate 8 with the transparent electrode 6 are provided.
And a single birefringent substrate 152 with a transparent electrode 7 and a liquid crystal cell section 50 sandwiching the liquid crystal layer 10 with the transparent electrodes 6 and 7 facing each other, and the birefringent substrate 156.
Sets the incident surface of light at a predetermined angle with respect to the optical axis,
The ferroelectric liquid crystal cell has a predetermined thickness and satisfies the half-wave plate condition of the ferroelectric liquid crystal cell.

With this construction, according to the third embodiment, in addition to the first and second effects, one glass substrate can be omitted, and the image forming position control means can be realized. The thickness is suppressed to 2 mm at most, and it can be relatively easily arranged in a short time between the rod lens array and the photosensitive drum as a photosensitive medium. Further, in the configuration of the image forming position control means, the light transmitted through the liquid crystal layer is directly incident on the birefringent substrate without passing through the air layer or the glass layer, so that the loss such as interface reflection can be reduced.

The other operations, actions, and effects are the same as those in the first embodiment, and therefore will be omitted. Next, a fourth embodiment of the present invention will be briefly described. FIG. 20 is a schematic diagram of an optical writing device of a light emitting element array printer showing a fourth embodiment of the present invention, and schematically showing its simple configuration and a writing light path.

In the figure, an optical writing device of a light emitting element array printer has a light emitting element array 1, an imaging position control means 61, a converging rod lens array 2, and a photosensitive drum 4 as a photosensitive medium. Image forming position control means 61 for changing the image forming position by changing the path by dispersing L
Is installed between the light emitting element array 1 and the converging rod lens array 2. That is, in the third embodiment described above, the image formation position control means 61 is arranged between the converging rod lens array 2 and the photosensitive drum 4 as the photosensitive medium, but in the fourth embodiment, the light emitting element array is used. 1 and the converging rod lens array 2 are installed.

Regarding the operation, action and effect in this case,
Since this is the same as the third embodiment, it will be omitted. Next, a fifth embodiment of the present invention will be described. FIG. 21 is a diagram schematically showing the configuration of the optical writing device of the light emitting element array printer and the path of writing light according to the fifth embodiment of the present invention.
In the figure, an optical writing device of a light emitting element array printer has a light emitting element array 101, a converging rod lens array 102, an image forming position control means 103, and a photosensitive drum 104 as a photosensitive medium. The path can be changed to change the image forming position.

FIG. 22 is a view showing the arrangement of the image forming position control means showing the fifth embodiment of the present invention. In the figure, the image forming position control means 103 indicates the birefringent plate 1 in order from the incident side of the light L.
52, a glass substrate 111 on which a transparent electrode 106 is formed on one surface and an alignment film (not shown) is formed, and a transparent electrode 10 on one surface.
Glass substrate 1 on which No. 7 is formed and an alignment film (not shown) is formed
08 is disposed so that the surfaces on which the alignment film and the transparent electrodes 106 and 107 are formed face each other, and the liquid crystal layer 110 is enclosed.
The liquid crystal cell unit 150 has a sealed structure, a drive circuit 151 for applying an electric signal to the liquid crystal cell unit 150, and a polarizing plate 105 having a transmission axis in a direction orthogonal to the main scanning direction of the optical printer. .

FIG. 23 is an explanatory view showing the function of the birefringent plate in the image forming position control means showing the fifth embodiment of the present invention. The birefringent plate 152 is the y in the birefringent plate 152.
The axis (the direction in which the optical axis a is projected on the incident side surface) is aligned with the main scanning direction. As the birefringent plate 152, a uniaxial crystal having optical anisotropy, for example, calcite is used.
An angle φ between the normal direction x of 52 and the optical axis a (where φ> 0
°) is a diagonal cut.

Here, the direction in which the optical axis a is projected on the incident side surface of the birefringent plate 152 is the y-axis, and the normal direction of the plane including the x-axis and the y-axis is the z-axis. The transmission of the light L incident on the birefringent plate 152 in the normal direction x will be described. When natural light is incident on the birefringent plate 152, the light is decomposed into the intrinsic polarized light of the birefringent plate 152 and travels as two light rays L1 and L2 having different directions.

L 1 is an extraordinary light component traveling in the optical axis direction of the birefringent plate, and while passing through this birefringent plate 152,
Within the plane (main cross section) including the normal direction x of the birefringent plate 152 and the optical axis a, the polarized light is displaced by the distance S and vibrates in the y-axis direction. L2 is an ordinary light component, which is polarized light vibrating in the z-axis direction and is transmitted as it is. That is, the incident light L
When being transmitted through the birefringent plate 152, is split into two polarized waves that vibrate orthogonally to each other, and is output from two points separated by a distance S from each other.

Next, the structure and operation of the liquid crystal cell portion in the image forming position control means will be described. In the liquid crystal cell unit 150, a ferroelectric liquid crystal having a chiral smectic C phase is used as the liquid crystal layer 110 (FIG. 22). FIG. 24 is a schematic diagram for explaining the switching of the ferroelectric liquid crystal in the fifth embodiment of the present invention.

The ferroelectric liquid crystal has a helical structure, but when sandwiched in a liquid crystal cell having a cell thickness smaller than the helical pitch, the helical structure is unraveled, and as shown in FIG. 24, the liquid crystal molecules 153 are formed by the smectic layer method. Tilt angle θ to the line
It is possible to realize a state in which a region that is stable by tilting (θ = 22.5 ° here) and a region that is stable by tilting by θ in the opposite direction are mixed.

In FIG. 24, W is the layer normal of the smectic phase, n is the major axis direction (director) of the liquid crystal molecule 153, and the symbol ● inside the circle and the + symbol inside the circle indicate the direction of spontaneous polarization. By applying an electric field in a direction perpendicular to the paper surface, the directions of the liquid crystal molecules 153 and their spontaneous polarization can be made uniform, and the state can be maintained.
Then, switching between the two states can be performed by switching the polarity of the applied electric field. That is, in FIG. 24, when an electric field of −E is applied, a state A tilted by −θ from the layer normal direction W of the smectic phase.
Then, by applying an electric field of + E, it is possible to stabilize the state in which the layer is inclined by θ from the layer normal direction W of the smectic phase, that is, the state B in which the orientation state of the state A is inclined by 45 °.

FIG. 25 is a schematic view showing the operation of the liquid crystal cell in which the ferroelectric liquid crystal is sealed according to the fifth embodiment of the present invention. In the figure, the thickness d of the liquid crystal layer 110 is determined by the wavelength λ of the transmitted light L (for example, 720 nm) and the refractive index anisotropy Δn of the liquid crystal material at 720 nm, and Δn × d = λ
/ 2 is satisfied (that is, the half-wave plate condition is satisfied).

The polarizing plate 105 is installed such that the transmission axis of the polarizing plate 105 and the main scanning direction of the optical printer are orthogonal to each other. The function of the liquid crystal cell unit 150 is to determine whether the polarization direction of the light L, which is transmitted through the birefringent plate 152 and is separated into two components, is transmitted while maintaining the polarization direction or rotated by 90 °. The transparent electrodes 106, 1 of the liquid crystal cell unit 150
By switching the polarity of the electric field applied to 07,
Select by switching between two states. That is,
When an electric field of −E is applied between the transparent electrodes 106 and 107, the liquid crystal molecules 153 are in the layer normal direction W of the smectic phase.
The liquid crystal cell unit 150 has an alignment state (stable state A) tilted by −θ from, and the incident polarized lights L1 and L2 of the light L pass through the liquid crystal cell unit 150 while maintaining the polarization direction.

On the other hand, when an electric field of + E is applied to the transparent electrodes 106 and 107, the liquid crystal molecules 153 have an alignment state (stable state B) tilted by + θ from the layer normal direction W of the smectic phase. In this case, since θ = 22.5 °, the liquid crystal molecule major axis (director) is 2θ = 4 with respect to the incident polarized light.
Orient at an angle of 5 °. As a result, the half-wave plate condition is satisfied, and the incident polarized light of the light L rotates the polarization direction by 90 ° while passing through the liquid crystal layer 110.

Next, the operation of the fifth embodiment of the present invention will be described. FIG. 26 is a light path diagram in the fifth embodiment of the present invention. Here, consider two light emitting areas of the LED array head. The pitch of the light emitting area 144 is
N μm, for example, 42.3 μm. Light emitting area 144a
The light L emitted from the rod lens array 1 is focused.
02, and the birefringent plate 15 of the imaging position control means 103.
It is incident on 2. By passing through the birefringent plate 152, the light L is linearly polarized light ● (L2) having a vibration direction in a direction orthogonal to the main scanning direction, and linearly polarized light ← → (L1) having a vibration direction in a direction parallel to the main scanning direction. ), L1 is L2
Output point k displaced from the output point k1 of S by S in the main scanning direction
It is output from 2.

Here, the case where a -E electric field is applied to the liquid crystal cell section 150 of the image forming position control means 103 to orient the liquid crystal molecules in the stable state A will be described. In the stable state A, the long axis direction (director direction) of the liquid crystal molecule 153.
Is installed so as to coincide with the main scanning direction of the optical printer.
Therefore, the light passes through the liquid crystal cell unit 150 while maintaining the polarization direction.

Of the light that has passed through the birefringent plate 152, the light L1 displaced by the distance S in the main scanning direction by the birefringent plate 152 is linearly polarized light ← → having an oscillation direction parallel to the main scanning direction, so The photosensitive drum 1 is absorbed by the plate 105.
04 is not irradiated. On the other hand, the linearly polarized light ● (L2) having a vibration direction orthogonal to the main scanning direction passes through the polarizing plate 105 and faces the light emitting area 144a.
The dots 154a above 4 are irradiated.

Next, the case where the electric field of E is applied to the liquid crystal cell section 150 of the image forming position control means 103 to orient the liquid crystal molecules 153 in the stable state B will be described. Liquid crystal molecule 15
3 is oriented in a direction inclined by 45 ° with respect to the incident polarized light. At this time, since the liquid crystal layer 150 satisfies the half-wave plate condition, the incident polarized light is rotated by 90 ° and passed through the liquid crystal layer.

Of the light passing through the birefringent plate 152, the light L1 displaced by the distance S in the main scanning direction is linearly polarized light ← → having an oscillation direction parallel to the main scanning direction. When it comes out, it is rotated by 90 ° and becomes a linearly polarized light ● having a vibration direction in a direction orthogonal to the main scanning direction. Therefore, it can pass through the polarizing plate 105 and irradiate the dot 155a (FIG. 26) on the photosensitive drum 104. The dot 155a is displaced by the distance S from the image forming position (dot 154a) when the -E electric field is applied to the liquid crystal cell unit 150.

The linearly polarized light ● (L2) having a vibration direction orthogonal to the main scanning direction is rotated by 90 ° when leaving the liquid crystal layer, and linearly polarized light having a vibration direction orthogonal to the main scanning direction ← Converted to →. Therefore, it cannot pass through the polarizing plate 105. Here, the displacement amount s can be represented by the following (1). S = [[D (b ² −a ² )] / 2c ² ] sin2φ (2) where D: thickness of birefringent plate a = 1 / ne, b = 1 / none; light of birefringent plate Refractive index no in the axial direction; refractive index φ in the direction orthogonal to the optical axis; angle between the normal direction x of the birefringent plate and the optical axis a is c ² = a ² sin ² φ + b ² cos ² φ.

Here, a case where calcite, which is a typical birefringent crystal, is used as the birefringent plate 152 will be described. If the incident light wavelength is 720 nm, calcite 720
The refractive index in nm is ne = 1.65, no = 1.4
8 At this time, the displacement amount S1 per 1 mm of the birefringent plate with respect to the angle φ formed by the optical axis a and the normal direction x of the birefringent plate.
Can be represented as shown in FIG.

For example, when the angle φ formed by the optical axis a and the normal direction x of the birefringent plate is φ = 5 °, 10 °, 50 °, the relationship between the thickness D and the displacement amount is proportional as shown in FIG. Becomes Therefore, the displacement amount S is half the pitch N μm of the light emitting areas 144 in the main scanning direction, for example, 42.3 μm, that is, N / 2.
For example, when the optical axis is 21.15 μm, the optical axis a
The angle φ between the normal direction x of the birefringent plate and φ = 5 °, and the thickness D may be 1.24 mm.

From the above formula (2), the displacement amount S is proportional to the thickness D, and the proportional constant S1 is the optical axis a and the normal direction x of the birefringent plate.
It can be determined by the angle φ formed by. Therefore, a desired displacement amount can be obtained by appropriately setting the angle φ formed by the optical axis a and the normal direction x of the birefringent plate and the thickness D. Therefore, Nμm, for example, 42.3μ
An LED array head with a resolution of m pitch can be used to irradiate the photosensitive drum with a resolution of N / 2 μm, for example, 21.15 μm in the main scanning direction.

The driving of the fifth embodiment of the present invention will be described. First, the liquid crystal cell unit 150 of the image forming position control means 103.
An electric field of −E is applied to the liquid crystal molecules 153 to uniformly orient the liquid crystal molecules 153 in the direction orthogonal to the main scanning direction (that is, state A).
To stabilize). Since the ferroelectric liquid crystal can maintain a stable state even if the electric field is removed, the electric field may be removed here.

The LED array head emits light in accordance with the odd number data of the print data for one line in the main scanning direction. At this time, since only the polarized light in the direction orthogonal to the main scanning direction, that is, the light that has not been displaced can be transmitted, the displacement of the imaging position does not occur. Then, an electric field of + E is applied to the liquid crystal cell unit 150 of the image forming position control unit to stabilize the liquid crystal layer in the state B, and the liquid crystal layer 110 is set to the half-wave plate condition.

The LED array head emits light in accordance with the even data of the print data for one line in the main scanning direction. At this time, since the polarization rotation of the light occurs, only the light displaced by the distance S in the main scanning direction irradiates the photosensitive drum 104. The printing for one line in the main scanning direction is completed, the photosensitive drum 104 is sent in the sub scanning direction, and the printing operation for the next line is continued.

Therefore, using the optical writing apparatus of the fifth embodiment of the present invention, using an LED array head having a resolution of N μm, for example, 42.3 μm pitch, N / 2 μm, for example, 21.15 μm in the main scanning direction. It is possible to irradiate on the photosensitive drum at a resolution and print. As described above, the light emitting element array head in which a plurality of light emitting elements are arranged at a pitch of N μm, and the photosensitive medium are disposed so as to face the light emitting element array head, and the light emitting element array head and the photosensitive medium are arranged. In an optical printer device in which a lens is disposed between the lenses and the photosensitive medium, the light emitted from the light emitting element is focused to form an electrostatic latent image on the photosensitive medium. A birefringent plate having a surface normal at a predetermined angle and a predetermined thickness, a ferroelectric liquid crystal cell designed to satisfy the half-wave plate condition, and an imaging position control means composed of a polarizing plate are arranged. I set it up.

The birefringent plate can displace a component of the incident light, which is parallel to the optical axis direction, by a predetermined amount in the main scanning direction, and is orthogonal to the optical axis direction. The components can be transmitted without displacement. For the ferroelectric liquid crystal cell, the polarization direction of the transmitted light of the ferroelectric liquid crystal cell is made parallel to the optical axis of the birefringent plate or rotated by 90 ° by switching the polarity of the electric signal. The light is output in the direction orthogonal to the optical axis of the birefringent plate.

Therefore, the LED array head emits light when the LED array head emits light in accordance with the odd number of the print data for one line and the even number of the print data for one line. At times
By switching the polarity of the electric signal applied to the liquid crystal cell of the imaging position control means, an LED array head having a resolution of N μm, for example, 42.3 μm pitch in the main scanning direction is used, and N / 2 μm, for example, in the main scanning direction. 21.1
The photosensitive drum can be irradiated with a resolution of 5 μm pitch and printing can be performed.

Therefore, it is possible to print with high resolution by using the light emitting element array printer with low resolution. On the contrary, it becomes possible to print at a higher resolution by using a high resolution light emitting element array printer. Various combinations that give the same effects as those of the above-described fifth embodiment are possible. That is, in the fifth embodiment, the main scanning direction is aligned with the direction in which the optical axis of the birefringent plate is projected on the incident surface, and the alignment direction of the liquid crystal molecules when a -E electric field is applied to the liquid crystal cell is aligned. The embodiment is one in which the transmission axis of the polarizing plate is orthogonal to the main scanning direction.

However, various combinations of the transmission axis direction of the polarizing plate, the alignment direction of the liquid crystal layer, and the incident surface projection direction of the optical axis of the birefringent plate that give the same effect can be considered. FIG. 29 shows an example of the combination. Here, the main scanning direction is made coincident with the direction in which the optical axis of the birefringent substrate is projected onto the incident surface. In the table, the combinations marked with ◯ are the combinations described in the examples of the present invention.

Therefore, other than the combination of installation directions described in the fifth embodiment, as long as the same effect can be obtained, it is not excluded from the scope of the present invention. Next, a sixth embodiment of the present invention will be described.
FIG. 30 is a schematic view of an optical writing device of a light emitting element array printer showing a sixth embodiment of the present invention, and schematically showing its simple configuration and the writing light path.

In the figure, an optical writing device of a light emitting element array printer has a light emitting element array 101, an image forming position control plate 103, a converging rod lens array 102, and a photosensitive drum 104 as a photosensitive medium. Image formation position control plate 1 that changes the image formation position by changing the path
03 is installed between the light emitting element array 101 and the converging rod lens array 102. That is, in the fifth embodiment described above, the image formation position control plate 103 is arranged between the converging rod lens array 102 and the photosensitive drum 104 as a photosensitive medium, but in the sixth embodiment, the light emitting element array is arranged. 101 and a converging rod lens array 102
It is supposed to be installed between. Operation in this case,
The operation and effect are the same as in the fifth embodiment,
Omit it.

Next, a seventh embodiment of the present invention will be described. FIG. 31 is a diagram schematically showing the configuration of the optical writing device of the light emitting element array printer and the path of writing light according to the seventh embodiment of the present invention, and FIG. 32 is the image formation position control showing the seventh embodiment of the present invention. It is a figure which shows the structure of a means. In addition, the fifth
The same parts as those in the embodiment are designated by the same reference numerals and the description thereof is omitted.

This seventh embodiment differs from the fifth embodiment in that
The configuration of the image forming position control means 103 is partially different. That is, as shown in FIG. 32, in order from the light emitting element side, a transparent electrode 106 is formed on one surface, a birefringent substrate 156 having an alignment film (not shown) formed thereon, and a transparent electrode is formed on one surface,
A liquid crystal cell unit 150 having a structure in which a glass substrate 108 on which an alignment film (not shown) is formed is disposed so that the surfaces on which the alignment film and the transparent electrodes 106 and 107 are formed face each other, and the liquid crystal layer 110 is sealed and sealed. And a drive circuit 151 for applying an electric signal to the liquid crystal cell section 150, and a polarizing plate 105 having a transmission axis in a direction orthogonal to the main scanning direction of the optical printer.

With such a configuration, according to the seventh embodiment, in addition to the effects of the fifth embodiment, one glass substrate can be omitted, and the image forming position control means can be realized. The thickness is suppressed to about 2 mm at most, and it can be relatively easily arranged in a short gap between the rod lens array and the photosensitive drum as the photosensitive medium. Further, since one glass substrate is omitted, the loss such as interface reflection can be reduced.

The other operations, actions, and effects are fifth.
Since it is the same as the embodiment, its explanation is omitted. Next, the eighth aspect of the present invention
Examples will be described. FIG. 33 is a diagram schematically showing the configuration of the optical writing device of the light emitting element array printer and the path of writing light according to the eighth embodiment of the present invention. FIG.
In the same manner as the sixth embodiment, the image forming position control means 103 is arranged between the light emitting element array 101 and the converging rod lens array 102, and the image forming position control means 1 is provided.
The configuration of 03 is the same as that of the seventh embodiment of the present invention.

Therefore, according to the eighth embodiment, in addition to the operational effects of the sixth embodiment, one glass substrate can be omitted, and the thickness of the image forming position control means is suppressed to about 2 mm at the most. Therefore, it can be relatively easily arranged in the short gap between the light emitting element array and the rod lens array. Also,
Since one glass substrate is omitted, loss such as interface reflection can be reduced.

The other operation, action and effect are No. 5
Since it is the same as the sixth embodiment, the description thereof will be omitted. Next, a ninth embodiment of the present invention will be described. FIG. 34 is a diagram schematically showing the configuration of the optical writing device of the light emitting element array printer and the path of writing light according to the ninth embodiment of the present invention.

In the figure, in the optical writing device of the light emitting element array printer, the light emitting area pitch of the light emitting elements is N μm.
Of the light emitting element array 101, the writing light L is split into two, one is transmitted as it is, and the other is displaced by half the light emitting area pitch of the light emitting elements, that is, N / 2 μm, and is transmitted through the birefringent plate 152. The focusing rod lens array 102, the ferroelectric liquid crystal cell 150 and the polarizing plate 105, which can be selected depending on the polarity of the electrode signal, either rotating the polarization direction of the incident polarization by 90 ° or transmitting the polarization without rotating the polarization direction. When the photosensitive drum 104 as a photosensitive medium is installed, the position on the photosensitive drum 104 facing the light emitting element is exposed by the polarity of the electric signal applied to the liquid crystal cell, and the light emitting area from the position facing the light emitting element. It is possible to expose areas that are offset by half the pitch.

Also in this ninth embodiment, the fifth embodiment of the present invention
Since the operation, action, and effect are similar to those of the embodiment, the description thereof will be omitted. Next, a tenth embodiment of the present invention will be described. FIG. 35 is a diagram schematically showing the structure of the optical writing device of the light emitting element array printer and the writing light path according to the tenth embodiment of the present invention.

In the figure, in the optical writing device of the light emitting element array printer, the light emitting area pitch of the light emitting elements is N μm.
Of the light emitting element array 101, the writing light L is split into two, one is transmitted as it is, and the other is displaced by half the light emitting area pitch of the light emitting elements, that is, N / 2 μm, and is transmitted through the birefringent plate 152. Depending on the polarity of the electrode signal, the ferroelectric liquid crystal cell 150, which can be selected to rotate the polarization direction of incident polarization by 90 ° or to transmit the polarization light without rotating the polarization direction, the converging rod lens array 102, and the polarizing plate 105, a photosensitive drum 104 as a photosensitive medium is installed, and when the position facing the light emitting element on the photosensitive drum 104 is exposed by the polarity of the electric signal applied to the liquid crystal cell, and when the position facing the light emitting element emits light. It is possible to expose a place shifted by half the area pitch, that is, N / 2 μm.

The tenth embodiment also has the same operation, function, and effect as the fifth embodiment of the present invention, and therefore the description thereof is omitted. Further, if the incident side glass substrate 111 of the liquid crystal cell 150 is replaced by a birefringent plate 156 having a transparent electrode formed on one surface and an alignment film formed as in the seventh embodiment, the operation in the fifth embodiment is achieved. In addition to the effect, one glass substrate can be omitted, and the loss such as interface reflection can be reduced.

Next, an eleventh embodiment of the present invention will be described. FIG. 36 is a diagram schematically showing the configuration of the optical writing device of the light emitting element array printer and the path of writing light according to the eleventh embodiment of the present invention. In the drawing, an optical writing device of a light emitting element array printer includes a light emitting element array 1 having a light emitting element light emitting area pitch of N μm, a polarizing plate 5 for converting writing light L into linearly polarized light, a converging rod lens array 2, an electric signal Depending on the polarity, the ferroelectric liquid crystal cell 5 can be selected between the case where the polarization direction of the incident polarization is rotated by 90 ° and the case where the polarization direction is transmitted as it is without being rotated.
0 and an optical axis component in the main scanning direction of the optical printer,
A birefringent plate having a predetermined thickness, when the polarization of the writing light L is orthogonal to the optical axis, it is transmitted as it is, and when the polarization of the writing light L is parallel to the optical axis, the light emitting area pitch of the light emitting element Half of that, that is, a birefringent plate 52 which is displaced by N / 2 μm and transmits the light, and a photosensitive drum 4 as a photosensitive medium.
Is installed, depending on the polarity of the electric signal applied to the liquid crystal cell, when the position facing the light emitting element on the photosensitive drum 4 is exposed, and when the position facing the light emitting element is shifted by half the light emitting area pitch. The place can be exposed.

The eleventh embodiment also has the same operation, function, and effect as those of the first embodiment of the present invention, so that the description thereof will be omitted. In addition, as in the third embodiment, the liquid crystal cell 5
If the birefringent substrate 156 in which the transparent electrode is formed on one surface and the alignment film is formed is substituted for the exit side glass substrate 9 of 0, one glass substrate can be omitted. In addition to the function and effect in the example, loss such as interface reflection can be reduced.

Next, a twelfth embodiment of the present invention will be described. FIG. 37 is a diagram schematically showing the configuration of an optical writing device of a light emitting element array printer and the path of writing light according to the twelfth embodiment of the present invention. In the figure, an optical writing device of a light emitting element array printer includes a light emitting element array 1 having a light emitting area pitch of N μm of light emitting elements, a polarizing plate 5 for converting writing light L into a linearly polarized light, and a polarization of an incident polarized light depending on a polarity of an electric signal. The ferroelectric liquid crystal cell 50, the focusing rod lens array 2, and the optical axis component in the main scanning direction of the optical printer, which can be selected between the case where the polarization direction is rotated by 90 ° and the case where the polarization direction is transmitted without being rotated, can be selected. Have,
It is a birefringent plate having a predetermined thickness, and when the polarization of the writing light L is orthogonal to the optical axis, it is transmitted as it is, and when the polarization of the writing light L is parallel to the optical axis, the light emitting area pitch of the light emitting element. , A birefringent plate 52 that is displaced by N / 2 μm and is transmitted, and the photosensitive drum 4 as a photosensitive medium are installed. Depending on the polarity of the electric signal applied to the liquid crystal cell, the photosensitive drum 4 emits light. It is possible to expose a position facing the element and a position offset from the position facing the light emitting element by a half of the light emitting area pitch.

The twelfth embodiment also has the same operation, action, and effect as those of the first embodiment of the present invention, and therefore the description thereof will be omitted. The present invention is not limited to the above-described embodiments, and various modifications can be made based on the spirit of the present invention, and these modifications are not excluded from the scope of the present invention.

[0108]

As described in detail above, according to the present invention, the following effects can be achieved. [A] Claims 1, 2, 3, 5, 7, 8, 9, 11 or 1
According to the optical writing device of the light emitting element array printer described in 2, the light emitting element array head in which a plurality of light emitting elements are arranged at intervals of N μm, and the light emitting element is arranged so as to face the light emitting element array head. The light emitted from the light emitting elements is focused and imaged on the photosensitive medium, which is disposed between the photosensitive medium that receives the emitted light and forms an electrostatic latent image and the light emitting element array head and the photosensitive medium. In an optical writing device of a light emitting element array printer having a lens, depending on the polarity of a polarizing plate and an applied electric signal, incident linearly polarized light is transmitted without changing the polarization direction or is rotated by 90 ° and is transmitted. , The ferroelectric liquid crystal cell and the incident surface are set at a predetermined angle with respect to the optical axis and have a predetermined thickness, and the optical axis direction component of the incident light is displaced by N / 2 μm in the main scanning direction of the optical printer. And transmit it, orthogonal to the optical axis The three components of the birefringent plate that directly pass the component are used to form an image at a position facing the light emitting element on the photosensitive medium for exposure, and the image forming position is shifted by N / 2 μm in the main scanning direction of the optical printer. The image forming position control means having the function of electrically selecting the exposure is provided.

Therefore, when the light emitting element array head performs the light emitting operation in accordance with the odd number data of the print data for one line, the image forming position is not displaced and the light emitting element array head is connected to the position facing the light emitting element on the photosensitive medium. When the light emitting element array head performs the light emitting operation according to the even number data of the print data for one line, the image forming position is shifted by N / 2 μm in the main scanning direction of the optical printer for exposure. By doing so, by using the light emitting element array head in which the light emitting areas are arranged at the pitch of N μm in the main scanning direction,
Exposure and printing can be performed at a pitch of 2 μm, which enables printing with higher resolution.

[B] According to the optical writing device of the light emitting element array printer according to claim 4, 6, 7, 10 or 13, one glass substrate is omitted in addition to the effect of [A]. Therefore, the optical printer optical system can be arranged relatively easily in a short time. In addition, it is expected that loss such as interface reflection will be reduced.

[Brief description of drawings]

FIG. 1 is a schematic view of an optical writing device of a light emitting element array printer showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an image forming position control unit in the optical writing device of the light emitting element array printer showing the first embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating switching of the ferroelectric liquid crystal showing the first embodiment of the present invention.

FIG. 4 is a schematic diagram showing the operation of a liquid crystal cell in which a ferroelectric liquid crystal is sealed according to the first embodiment of the present invention.

FIG. 5 is an explanatory view showing the structure and function of a birefringent plate in the image forming position control means according to the first embodiment of the present invention.

FIG. 6 is a light path diagram in the first embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between an angle φ formed by an optical axis of a birefringent plate and a surface normal of the birefringent plate and a displacement amount S1 per 1 mm of the birefringent plate in the first embodiment of the present invention.

FIG. 8 is a diagram showing the relationship between the thickness D of the birefringent plate and the displacement amount S when the angle φ = 5 ° formed by the optical axis and the normal direction x of the birefringent plate in the first embodiment of the present invention. Is.

FIG. 9 is a pass axis of the polarizing plate in the first embodiment of the present invention,
It is a figure which shows the combination of the liquid crystal molecule director direction and the direction which projected the optical axis of a birefringent plate on the incident surface.

FIG. 10 is a schematic view of an optical writing device of a light emitting element array printer showing a second embodiment of the present invention.

FIG. 11 is a schematic view of a conventional LED printer.

FIG. 12 is an enlarged perspective view of an optical image forming system of a conventional light emitting element array printer.

FIG. 13 is a conceptual diagram of an optical imaging system of a conventional light emitting element array printer.

FIG. 14 is a plan view of a conventional LED array head.

FIG. 15 is a diagram showing a light emitting portion of a conventional LED array chip.

FIG. 16 is a perspective view showing a boundary portion of a conventional LED array chip.

FIG. 17 is a diagram schematically showing a configuration of an optical writing device of a light emitting element array printer and a path of writing light according to a third embodiment of the present invention.

FIG. 18 is a diagram showing a configuration of an image forming position control means showing a third embodiment of the present invention.

FIG. 19 is a light path diagram in the third embodiment of the present invention.

FIG. 20 is a schematic view of an optical writing device of a light emitting element array printer showing a fourth embodiment of the present invention.

FIG. 21 is a diagram schematically showing a configuration of an optical writing device of a light emitting element array printer and a writing light path according to a fifth embodiment of the present invention.

FIG. 22 is a diagram showing a configuration of an image forming position control means showing a fifth embodiment of the present invention.

FIG. 23 is an explanatory diagram showing a function of a birefringent substrate which is an incident substrate of a liquid crystal cell section in an image forming position control means showing a fifth embodiment of the invention.

FIG. 24 is a schematic diagram for explaining switching of ferroelectric liquid crystal in the fifth embodiment of the present invention.

FIG. 25 is a schematic diagram showing the operation of a liquid crystal cell in which a ferroelectric liquid crystal is sealed according to the fifth embodiment of the present invention.

FIG. 26 is a light path diagram of the fifth embodiment of the present invention.

FIG. 27 is a diagram showing the relationship between the angle φ formed by the optical axis and the normal to the incident surface and the displacement amount S1 per 1 mm of the crystal plate in the fifth embodiment of the present invention.

FIG. 28 is an angle φ = 5 formed between the optical axis and the normal direction of the birefringent plate.
It is a figure which shows the relationship between the thickness of a birefringent plate, and the amount of displacement when it is set to (degrees), 10 degrees, and 15 degrees.

FIG. 29 is a diagram showing a combination of a pass axis of a polarizing plate, a liquid crystal molecule director direction, and a direction in which an optical axis of a birefringent plate is projected on an incident surface in a fifth example of the present invention.

FIG. 30 is a diagram schematically showing a configuration of an optical writing device of a light emitting element array printer and a writing light path according to a sixth embodiment of the present invention.

FIG. 31 is a diagram schematically showing a configuration of an optical writing device of a light emitting element array printer and a path of writing light according to a seventh embodiment of the present invention.

FIG. 32 is a diagram showing a configuration of an image forming position control means showing a seventh embodiment of the present invention.

FIG. 33 is a diagram schematically showing a configuration of an optical writing device of a light emitting element array printer and a writing light path according to an eighth embodiment of the present invention.

FIG. 34 is a diagram schematically showing a configuration of an optical writing device of a light emitting element array printer and a writing light path according to a ninth embodiment of the present invention.

FIG. 35 is a diagram schematically showing a configuration of an optical writing device of a light emitting element array printer showing a tenth embodiment of the present invention and a writing light path.

FIG. 36 is a diagram schematically showing a configuration of an optical writing device of a light emitting element array printer showing an eleventh embodiment of the present invention and a writing light path.

FIG. 37 is a diagram schematically showing a configuration of an optical writing device of a light emitting element array printer and a path of writing light according to a twelfth embodiment of the present invention.

[Explanation of symbols]

1, 101 Light emitting element array 2, 102 Focusing rod lens array 3, 61, 103 Imaging position control means 4, 104 Photosensitive drum (photosensitive medium) 5, 105 Polarizing plate 6, 7, 106, 107 Transparent electrode 8, 9, 108, 111 Glass substrate 10, 110 Liquid crystal layer 44, 44a, 144, 144a, 144b Light emitting area 50, 150 Liquid crystal cell part 51, 151 Drive circuit 52, 152 Birefringent plate 53, 153 Liquid crystal molecule 54a, 55a, 154a , 155a dot 156 birefringent substrate

Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H04N 1/036 A (72) Inventor Hiromasa Sugano 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (72) Inventor Shigeki Ogura 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (72) Inventor Yuji Terauchi 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. Within

Claims (13)

[Claims] 1. A light emitting element array head in which a plurality of light emitting elements are arranged at N μm intervals, and a light emitting element array head which is arranged so as to face the light emitting element array head and receives light emitted from the light emitting element,
A light emitting element array printer having a photosensitive medium for forming an electrostatic latent image and a lens arranged between the light emitting element array head and the photosensitive medium, for converging light emitted from the light emitting element to form an image on the photosensitive medium. In the optical writing device, the image is exposed between the lens and the photosensitive medium at a position facing the light emitting element on the photosensitive medium, and the image forming position is shifted by N / 2 μm in the main scanning direction of the optical printer. An optical writing device for a light emitting element array printer, which is provided with an image forming position control means having a function of electrically selecting exposure by light exposure. 2. The optical writing device for a light emitting element printer according to claim 1, wherein the image forming position control means makes the light emitted from the light emitting element linearly polarized light in the order of the writing light path from the light emitting element side. Depending on the plate and the polarity of the electric signal to be applied, the incident linearly polarized light is transmitted without changing the polarization direction, or is rotated by 90 ° and is transmitted, and a predetermined direction with respect to the optical axis. Set the incident surface at the angle of
A birefringent plate that has a predetermined thickness and is transmitted by displacing the component of the incident light in the optical axis direction by N / 2 μm in the main scanning direction of the optical printer and transmitting the component orthogonal to the optical axis as it is An optical writing device for a light emitting element array printer, which is characterized by being provided. 3. The optical writing device for a light emitting element printer according to claim 1, wherein the image forming position control means converts the light emitted from the light emitting element into linearly polarized light in the order of the writing light path from the light emitting element side. Ferroelectric liquid crystal cell in which a plate, one glass substrate with a transparent electrode, and another glass substrate with a transparent electrode are subjected to orientation treatment, and the transparent electrodes are opposed to each other to sandwich a ferroelectric liquid crystal. And the incident surface is set at a predetermined angle with respect to the optical axis and has a predetermined thickness, and the component of the incident light in the optical axis direction is N / 2 μm in the main scanning direction of the optical printer.
An optical writing device for a light-emitting element array printer, characterized in that a birefringent plate that displaces and transmits the light and transmits the component orthogonal to the optical axis as it is is connected. 4. The light writing device for a light emitting element printer according to claim 1, wherein the image forming position control means makes the light emitted from the light emitting element linearly polarized light in the order of the writing light path from the light emitting element side. A plate, a glass substrate with a transparent electrode, and a transparent electrode are attached, and the incident surface is set at a predetermined angle with respect to the optical axis, and the optical axis of the incident light has a predetermined thickness. The directional component is displaced by N / 2 μm in the main scanning direction of the optical printer to be transmitted, and the component orthogonal to the optical axis is transmitted as it is. An optical writing device for a light emitting element array printer, characterized in that ferroelectric liquid crystal cells sandwiching a ferroelectric liquid crystal are arranged so as to be opposed to each other. 5. The light writing device for a light emitting element printer according to claim 1, wherein the image forming position control means sets an incident surface at a predetermined angle with respect to the optical axis in the order of the writing light path from the light emitting element side. However, a birefringent plate having a predetermined thickness and transmitting the component of the incident light in the optical axis direction by displacing it by N / 2 μm in the main scanning direction of the optical printer and transmitting the component orthogonal to the optical axis as it is, A glass substrate with a transparent electrode and another glass substrate with a transparent electrode are subjected to an alignment treatment, each transparent electrode is made to face each other, and a ferroelectric liquid crystal cell sandwiching a ferroelectric liquid crystal and a polarized light An optical writing device for a light emitting element array printer, characterized in that the optical writing device is arranged by connecting with a plate. 6. The optical writing device for a light emitting element printer according to claim 1, wherein the image forming position control means is provided with one transparent electrode in the order of the writing light path from the light emitting element side and with respect to the optical axis. The birefringence is configured such that the light incident surface is set at a predetermined angle, the light has a predetermined thickness, and the component of the incident light in the optical axis direction is displaced by N / 2 μm in the main scanning direction of the optical printer to be transmitted. A transparent substrate and a glass substrate with a transparent electrode, an alignment treatment is performed, and the transparent electrodes are opposed to each other, and the ferroelectric liquid crystal cell in which the ferroelectric liquid crystal is sandwiched is connected to the polarizing plate. An optical writing device for a light emitting element array printer, which is characterized by being provided. 7. A light emitting element array head in which a plurality of light emitting elements are arranged at N μm intervals, and a light emitting element array head which is arranged so as to face the light emitting element array head and receives light emitted from the light emitting element,
A light emitting element array printer having a photosensitive medium for forming an electrostatic latent image and a lens arranged between the light emitting element array head and the photosensitive medium, for converging light emitted from the light emitting element to form an image on the photosensitive medium. In the optical writing device, the image is exposed between the light emitting element array head and the lens at a position facing the light emitting element on the photosensitive medium, and the image forming position is set to N in the main scanning direction of the optical printer. / 2 μm
7. An optical writing device for a light emitting element array printer, comprising the image forming position control means according to claim 2, 3, 4, 5 or 6, which has a function of electrically selecting shifting and exposing. . 8. A light emitting element array head having a plurality of light emitting elements arranged at intervals of N μm, and a light emitting element array head which is arranged so as to face the light emitting element array head, receives light emitted from the light emitting elements,
A light emitting element array printer having a photosensitive medium for forming an electrostatic latent image and a lens arranged between the light emitting element array head and the photosensitive medium, for converging light emitted from the light emitting element to form an image on the photosensitive medium. In the optical writing device, the polarizing plate that linearly polarizes the light emitted from the light emitting element, the focusing lens, the glass substrate with the transparent electrode, and the other one in the order of the writing light path from the light emitting element side. A glass substrate with transparent electrodes is subjected to an alignment treatment, each transparent electrode is made to face each other, and a ferroelectric liquid crystal cell sandwiching a ferroelectric liquid crystal and light incident at a predetermined angle with respect to the optical axis. A birefringent plate which has a predetermined surface and which has a predetermined thickness, transmits the component of the incident light in the optical axis direction by displacing it by N / 2 μm in the main scanning direction of the optical printer, and transmits the component orthogonal to the optical axis as it is. Characterized by connecting and arranging Optical writing device that the light emitting element array printer. 9. A light emitting element array head in which a plurality of light emitting elements are arranged at N μm intervals, and a light emitting element array head which is arranged so as to face the light emitting element array head and receives light emitted from the light emitting element,
A light emitting element array printer having a photosensitive medium for forming an electrostatic latent image and a lens arranged between the light emitting element array head and the photosensitive medium, for converging light emitted from the light emitting element to form an image on the photosensitive medium. In the optical writing device, a polarizing plate that linearly polarizes the light emitted from the light emitting element in the order of the writing light path from the light emitting element side, one glass substrate with a transparent electrode, and another glass with a transparent electrode. The substrate is subjected to an alignment treatment, the transparent electrodes are opposed to each other, and the ferroelectric liquid crystal cell sandwiching the ferroelectric liquid crystal, the focusing lens, and the incident surface at a predetermined angle with respect to the optical axis. A birefringent plate that has a specified thickness and that transmits the component of the incident light in the optical axis direction displaced by N / 2 μm in the main scanning direction of the optical printer and transmits the component orthogonal to the optical axis as it is Characterized by being arranged The optical writing device of the optical element array printer. 10. A light emitting element array head in which a plurality of light emitting elements are arranged at N μm intervals, and an electrostatic latent array which is arranged so as to face the light emitting element array head and receives light emitted from the light emitting elements. Optical writing of a light emitting element array printer having a photosensitive medium for forming an image and a lens arranged between the light emitting element array head and the photosensitive medium and condensing light emitted from the light emitting element to form an image on the photosensitive medium. In the device, in order of the writing light path from the light emitting element side, a polarizing plate for linearly polarizing the light emitted from the light emitting element, a converging lens, a glass substrate with a transparent electrode and a transparent electrode are provided. The incident surface is set at a predetermined angle with respect to the optical axis and has a predetermined thickness, and the component of the incident light in the optical axis direction is displaced by N / 2 μm in the main scanning direction of the optical printer and transmitted. The component orthogonal to the optical axis is In addition, a birefringent substrate that is configured to transmit light is subjected to an alignment treatment, and the transparent electrodes are opposed to each other and the ferroelectric liquid crystal cell in which the ferroelectric liquid crystal is sandwiched is connected and arranged. Optical writing device for light emitting element array printer. 11. A light-emitting element array head having a plurality of light-emitting elements arranged at N μm intervals, and a light-emitting element array head which is arranged so as to face the light-emitting element array head, receives light emitted from the light-emitting elements, and receives an electrostatic latent image. Optical writing of a light emitting element array printer having a photosensitive medium for forming an image and a lens arranged between the light emitting element array head and the photosensitive medium and condensing light emitted from the light emitting element to form an image on the photosensitive medium. In the device, the incident surface is set at a predetermined angle with respect to the optical axis in the path order of the writing light from the light emitting element side and has a predetermined thickness, and the optical axis direction component of the incident light is the main scanning direction of the optical printer. N / 2 μm
A birefringent plate that displaces and transmits, and transmits components that are orthogonal to the optical axis as it is, a focusing lens, and a glass substrate with a transparent electrode and another glass substrate with a transparent electrode, oriented An optical writing device for a light-emitting element array printer, characterized in that a ferroelectric liquid crystal cell sandwiching a ferroelectric liquid crystal and a polarizing plate are arranged so as to be connected to each other by subjecting respective transparent electrodes to each other after treatment. . 12. A light emitting element array head having a plurality of light emitting elements arranged at intervals of N μm, and a light emitting element array head which is arranged so as to face the light emitting element array head, receives light emitted from the light emitting elements, and electrostatic latent Optical writing of a light emitting element array printer having a photosensitive medium for forming an image and a lens arranged between the light emitting element array head and the photosensitive medium and condensing light emitted from the light emitting element to form an image on the photosensitive medium. In the device, the incident surface is set at a predetermined angle with respect to the optical axis in the path order of the writing light from the light emitting element side and has a predetermined thickness, and the optical axis direction component of the incident light is the main scanning direction of the optical printer. N / 2 μm
Displaced and transmitted, the birefringent plate that transmits the component orthogonal to the optical axis as it is, one glass substrate with a transparent electrode and another one glass substrate with a transparent electrode, an orientation treatment is applied,
Light of a light emitting element array printer characterized in that a ferroelectric liquid crystal cell sandwiching a ferroelectric liquid crystal, a converging lens, and a polarizing plate are connected to each other with respective transparent electrodes facing each other, and arranged. Writing device. 13. A light emitting element array head having a plurality of light emitting elements arranged at intervals of N μm, and an electrostatic latent array head arranged to face the light emitting element array head and receiving light emitted from the light emitting elements. Optical writing of a light emitting element array printer having a photosensitive medium for forming an image and a lens arranged between the light emitting element array head and the photosensitive medium and condensing light emitted from the light emitting element to form an image on the photosensitive medium. In the device, one transparent electrode is attached in the order of the writing light path from the light emitting element side, the incident surface is set at a predetermined angle with respect to the optical axis, and the optical axis of the incident light has a predetermined thickness. A birefringent substrate, which is configured so that the directional component is displaced by N / 2 μm in the main scanning direction of the optical printer and is transmitted, and a glass substrate with a transparent electrode are subjected to alignment treatment, and each transparent electrode is opposed to the other. Let the ferroelectric liquid A ferroelectric liquid crystal cell which sandwiches, optical writing device of the light emitting element array printer, characterized by arranging connects the polarizing plate and the converging lens.