JPS59131910A - Imaging device - Google Patents

Abstract

PURPOSE:To increase speed by impressing positive and negative electric fields on a liquid panel wherein a liquid crystal having a chiral smectic C phase or H phase is sandwiched between two sheets of glass plates having ''NESA'' electrodes on the inside and controlling the intensity of transmitted light. CONSTITUTION:Light of a light source 220 is on-off controlled in a liquid crystal panel parts 211-218, and the transmitted light is formed an image on a photoreceptor by a condenser lens 221. The liquid crystal panels are sandwiched by polarizing plates 211 and consist of ''NESA'' electrodes 213 coated on glass plates 212 by vapor deposition, sputtering, dipping, etc. and further formed by photoetching, thin metallic films 214 of an optical mask, insulation films 215 and orientation control films 216 for liquid crystals. A chiral smectic liquid crystal 218 such as decyl oxybenzylidene p'-amino 2-metabutylcinnamate, hexyl oxybenzylidene p'-amino 2-chloropropyl cinnamate or the like is sandwiched by seals 217 and the liquid crystal panel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing device using a liquid crystal light valve.
In particular, printing devices using high-speed liquid crystal light valves made of liquid crystal materials that respond more quickly to polarity due to the strong coupling between the applied electric field and molecular orientation. OA (office automation) equipment is rapidly becoming popular. O
Printers, which are one of the terminal devices in A, are also required to be high speed, high print quality, and low cost.As a printing device for this purpose, a liquid crystal light valve is used as an optical signal generator. A printing device that applies electrophotographic technology is being put into practical use.The liquid crystal light valve of this printing device uses a two-frequency driving force type, low frequency and high frequency, to make the liquid crystal molecules stand up or lie down. Controls the intensity of transmitted light. With this method, unlike the normal display device drive method, voltage is applied to the liquid crystal even when it is turned off, so the response speed is nearly 100 times faster than conventional liquid crystal display devices.In reality, the response speed is about 1 to ltrm. Become. Although such a liquid crystal light valve is quite satisfactory in terms of low price and high print quality, it is still insufficient in terms of high speed.The present invention was made with attention to the above points. The present invention provides a printing device that maintains the low cost and high print quality of conventional liquid crystal light valves, and achieves even faster response.

In other words, the liquid crystal light valve can be replaced with a conventional nematic liquid crystal.
It uses chiral smectic liquid crystal to achieve high-speed response from a frequency drive system. The high-speed response of chiral smectic liquid crystals and its principle are disclosed in Japanese Patent Application Laid-Open No. 56-1.
07216 in detail. Liquid crystals used in liquid crystal light valves, including common display devices, utilize dielectric alignment effects in nematic, smectic, and cholesteric phases. In this case, the force applied to the liquid crystal molecules is proportional to the square of the applied electric field, so when driven with a relatively low electric field, the force suddenly weakens and the response speed becomes slow.
In contrast, chiral smectic liquid crystals have ferroelectricity, so each molecule has a permanent dipole. Therefore, the force applied to liquid crystal molecules is proportional to the applied electric field, and it is possible to change the arrangement of dipoles and molecules even in a relatively low electric field, resulting in high-speed response.Furthermore, compared to conventional liquid crystals, the force is 1000
~10,000 times faster response speed can be obtained.

FIG. 1 shows an outline of the configuration of a printing device using the liquid crystal light valve of the present invention. 102 is charged in advance by a corona charger 110. At this time, when printing characters, the light signal is usually generated in correspondence with the character portions.

As a result, an electrostatic latent image is formed and the magnetic brush developer 10
Toner development is performed in step 5@The development method at this time is usually reversal development. Thereafter, the toner is transferred onto plain paper 104 by a transfer corona discharger 105 and fixed by a fixing device 106. The toner remaining on the photosensitive drum after transfer is removed by a blade 108, and the electrostatic latent image is removed by a static elimination lamp 109.
The static electricity is removed and the process ends.

FIG. 2 shows the configuration of the optical signal generator. The light emitted from the light source 220 is 0N-OF at the liquid crystal panel section (211 to 218).
The transmitted light is subjected to F control and is imaged onto a photoreceptor by a condensing lens 221. The liquid crystal panel is sandwiched between two polarizing plates 211, and is coated on a glass plate 212 by vapor deposition, sputtering, dipping, etc., and is formed by photoetching. A metal thin film 214 used as an optical mask, and an insulating film are formed on the glass plate 212. Film 215, liquid crystal alignment control film 21
6, the seal 217 and the liquid crystal panel display the liquid crystal 2.
He is holding 18.

FIG. 3 is a front view of the liquid crystal panel, which consists of a group of micro shutters 302 that transmit and block light, and a light mask section 301 that constantly blocks light.

The present invention will be described in more detail below with reference to Examples.

Example 1 As a chiral smectic liquid crystal, decyloxybenzylidene p'-amino 2 methylbutyl cinname) (DO
BAMBO) was used to create a liquid crystal panel section. The liquid crystal panel is made by sputtering Info3 onto a glass plate 212 and photoetching it to form Nesa Den Wi213, a nickel vapor deposited film 214 as an optical mask, an insulating film 215 made of SiO, and a polyimide resin film as a liquid crystal alignment control film. The panels were further rubbed in parallel in the same direction on the top and bottom, and then bonded together so that the cell thickness was 0.1 to 5.0 μm.Polarizing plates 211 were then set on the top and bottom of this panel, and the optical axis of one polarizing plate was set. about 22.5 in the rubbing direction
The optical axis of the other polarizing plate was arranged perpendicularly to the other polarizing plate by shifting the angle by a degree (changeable arbitrarily depending on temperature, voltage, etc.).

This liquid crystal light valve was incorporated into a printing device having the configuration shown in FIG. 1, and writing was performed by applying a square wave of ±5 V. The resulting prints were as good as those using conventional liquid crystal light valves. Furthermore, the response speed of the liquid crystal light valve of the present invention was 13 μ(6), and the contrast ratio was also good at 18:1.

Example 2 As a chiral smectic liquid crystal, hexyloxybenzylidene p'-amino 2chloropropyl cinnamate (
HOBAOPO) was sealed in the same liquid crystal panel as in Example 1, and installed in a printing device having the configuration shown in Fig. 1. When a rectangular waveform of ±10V was applied and writing was performed, good printing was obtained. Obtained. Furthermore, the response speed of the liquid crystal light valve of the present invention was 8 μm, and the contrast ratio was good at 16:1.As described above, the present invention can achieve low cost and high printing quality without sacrificing the low price and high printing quality of conventional liquid crystal light pulp. , which provides a completely new printing device that achieves ultra-high speed.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of a printing apparatus using a liquid crystal light valve according to the present invention. FIG. 2 is a schematic diagram showing the configuration of the optical signal generating section of the present invention, and FIG. 3 is a front view of the liquid crystal panel of the present invention. 101... Optical signal generating unit 102... Photosensitive drum 103... Magnetic brush developer 104... Plain paper 105... Transfer corona discharger 106... Fixing device 108... Blade 109... - Static elimination lamp 110...Corona charger 211...Polarizing plate 212...Glass plate 213...NESA electrode 214...Optical mask 215...Insulating film 216...Orientation control film 217...・Seal 218...Liquid crystal 220...Light source 221...Condensing lens 301...Light mask section 302...One or more groups of micro shutters Applicant Suwa Seikosha Co., Ltd. Agent Patent attorney Tsutomu Mogami

Claims (1)

[Claims] In an optical printing device that includes a light source, a liquid crystal light valve, a light signal generating section having a liquid crystal driving circuit, a photosensitive section, a developing section, and a fixing section, the liquid crystal light valve includes two sheets having Nesa electrodes inside and subjected to alignment treatment. A liquid crystal panel comprising two glass plates facing each other and a liquid crystal having a chiral smectic C phase or smectic H phase sandwiched therebetween, and the display is characterized in that the intensity of transmitted light is controlled by applying a positive or negative electric field. Photography device.