JPS61158478A - Image-forming device - Google Patents

Abstract

PURPOSE:To contrive enhancement and stabilization of positional accuracy of each element in a printing head, by a construction wherein a liquid crystal shutter array and an image-formign optical system are unitized, and a LED light source is also unitized. CONSTITUTION:A liquid crystal panel 304 and a selfoc lens array 305 are unitized by positioningly fixing them to a casing 301. A LED unit 306 is fixed to a LED fitting frame 392-shaped in cross section so that the unit 306 can be detached from the casing 301 together with the frame 392. Accordingly, the spacing between component parts can be constantly fixed, and with the positional accuracy enhanced, favorable printed images can be obtained.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an image forming method in which a large number of liquid crystal elements are arranged and light is controlled by switching to form non-turns such as characters on the surface of a photoreceptor. It is related to the device.

[Background of the invention]

In recent years, electrostatic printers have been proposed that convert electrical signals such as computer output into optical signals and use electrophotographic copying processes to obtain hard copies of characters and graphics. Printers have been used. However, this radar beam system has many problems such as a large optical writing system including a mechanical beam scanning system and an expensive device.

Therefore, as an alternative to this laser beam printer, a device using liquid crystal as a light shutter was considered. This has been achieved by integrating liquid crystal elements and improving responsiveness to drive control, etc.), and it is expected that devices will become smaller and cheaper.

However, for example, as shown in FIG.
04, and the glossy turn of this liquid crystal shutter is projected by the imaging optical system 305 onto the photoreceptor drum 2, which is the image receiving surface, so when the fluorescent lamp 302 is used as a light source, The rise in temperature of the fluorescent lamp causes the temperature near the liquid crystal panel to rise, causing a problem in which the operation of the liquid crystal is no longer guaranteed. To eliminate this problem, it is necessary to increase the distance between the 1-LCD I4 channel 304 and the fluorescent light source 302, and to compensate for the lack of light intensity at both ends of the fluorescent light source 302, If the fluorescent lamp light source 302 is provided with a socket or hole, or if the total length of the fluorescent lamp light source 302 is set to be long in order to ensure that the fluorescent lamp light source 302 is irradiating effectively,
There is a problem that the print head becomes large. Furthermore, since the amount of light emitted by the fluorescent lamp light source 302 changes greatly depending on the surrounding temperature, complicated control mechanisms such as temperature control and dimming are required, and furthermore, it takes a long time to stabilize the amount of light from the fluorescent lamp. However, there are problems in that it usually takes about 1 to 2 minutes, resulting in waiting time.

Instead of the above fluorescent light source K, a light emitting diode (LED) is used.
), but in the case of using light emitting diodes, the operation is instantaneous, it can be made smaller compared to fluorescent lights, and it has good durability (long life). However, on the other hand, in the case of a light emitting diode light source, even if a large number of light emitting diode elements, for example, 100, are arranged in an array, the amount of light is insufficient, and the process as the main body of the device is difficult. There is a problem where the speed is reduced. In order to solve this problem, even if a high-brightness light-emitting diode (emission wavelength of around 660 nm) is used and a light condensing means described below is installed, the amount of light obtained using a fluorescent lamp (same wavelength as a high-brightness light-emitting diode) is approximately I could only get as close as 1/2. In addition, when a current of 1 rated current or more is applied to increase the light intensity of a light emitting diode, the life of the light emitting diode is proportional to the square of the current, and the life of the light emitting diode is shortened in proportion to the square of the current. Even if a certain light emitting diode is used, if a current twice the rated current flows through it, 2
The lifespan is about 50 hours.

For this reason, although the liquid crystal channel 304 and the imaging optical system 305 can be used almost permanently, only the light emitting diode light source requires frequent replacement.

Furthermore, a light source using a group of light emitting diodes cannot obtain the required illuminance simply by arranging bare light emitting diode chips.

Furthermore, as shown in FIG. 5(b) @(e), it is necessary to provide a substrate 101 made of aluminum, galray, etc., and a condensing cylindrical lens 103 for condensing the light from a large number of light emitting diodes 102. However, the more the light source is focused, the higher the positional accuracy between the shutter part of the liquid crystal shutter array and the light emitting diode light is required, and the light emitting diode array is frequently
cProblems such as requiring skill to replace with high positional accuracy ^
was there.

[Purpose of the invention]

The present invention has been made with attention to such problems, and includes a liquid crystal shutter array formed by arranging a large number of minute liquid crystal elements, and a pattern of a portion of the liquid crystal shutter array, which is imaged on a photoreceptor. The imaging optical system is made into a unit, and the light emitting diode light source is also made into a unit to form the print head. This improves and stabilizes the positional accuracy of each element in the print head, and also makes it possible to improve the positional accuracy of each element in the print head. An image forming apparatus in which a light source can be easily replaced by sliding it relative to a unit of a liquid crystal shutter array and an imaging optical system, thereby making it possible to obtain stable printed images. The purpose is to provide the following.

[Embodiments of the invention]

The present invention will be explained in detail below based on the embodiments shown in FIGS. 1 to 4.

FIG. 1 is a schematic diagram of an electrostatic printer 1 according to the present embodiment, and the electrostatic printer 1 is arranged around a photosensitive drum 2 that is rotatably supported in the direction of the arrow. To print, do 3, developing device 4, charger device 5 for transfer and static elimination, cleaning unit 6, eraser run f
8, a charging charger 9, etc. are sequentially arranged.

Recording paper P is stacked and held in a tray C, and paper feed roller 1
0 rotation, the sheets are fed one by one starting from the top one, and after being temporarily stopped by the timing roller 11,
The photoreceptor drum 20 is transported in synchronization with the image formed on the surface thereof, and after the toner image is transferred by the transfer charger 51, the close contact with the photoreceptor drum 2 is released by the static elimination charger 52, and the transport bell) 12, the image is sent to a heat roller fixing device 13, where the image is fixed, and then transferred to a discharge roller 2.
14, the paper is discharged onto a tray 15.

Although the electrostatic printer 1 described above is well known, the present invention is characterized by the print head 3 included in the electrostatic printer 1 having the above structure.

That is, the configuration of this cylinder head 3 will be explained based on FIGS. 2 to 4. The print head 3 includes a light emitting diode unit 306, a liquid crystal armpit 304, and a SELFOC (trade name) lens for image projection. The basic configuration is a combination with an array 305, and the liquid crystal 14 channel 304, self-cleaning array 305, and the casing 301K.

It is fixed in position and is made into a unit.

Further, the light emitting diode unit 306 is fixed to a light emitting diode mounting frame 3921C having a substantially U-shaped cross section. The light emitting diode unit 306 is slidably positioned and configured so that it can be removed from the casing 301, ie, the print head 3, together with the mounting frame 392, if necessary.

In this way, in this example, to the cylinder υ, do 3 ha,
LCD Nononel 304 and SELFOC lens array 305
are positioned within one casing 301 to form a unit, and also a light emitting diode unit) 30
6 is positioned on the casing 301 km through the mounting frame 392, so each unit, that is, the liquid crystal panel 30
4. Since the distance between each component such as the SELFOC lens array 305, light emitting diode unit 306, and photoreceptor drum 2 can be maintained without fluctuation, a good printed image can be obtained by improving the positional accuracy. be able to. Furthermore, the light emitting diode unit 306 is detachably attached to the casing 301 in a sliding manner.
[Summary of the Invention] As described above, the present invention provides a light source unit composed of a light emitting diode, etc., and a light source unit that allows the light source unit to change the light beam between the light blocking state and the light blocking state. A print head equipped with a micro-shutter array consisting of a liquid crystal etc. that is controlled to either a transparent state and the print head V In the prisoner-of-war device, a holding panel for the micro-shutter array and a coupling optical member for forming an image of the pattern of the micro-shutter array on an image holding member are attached to a casing to form an integrated unit;
Further, in the image forming apparatus, the light source units are detachably attached to the casing.

〔Effect of the invention〕

Therefore, according to this image forming apparatus, each component such as the light emitting diode auto unit, the liquid crystal shutter array, and the coupling optical member is positioned with respect to each other via the casing, so that the positional accuracy of each component is improved. can improve,
This has the effect of providing stable and high quality printed images. Further, since the light emitting diode unit described above is removably positioned by the casing, the light emitting diode unit can be easily and reliably replaced.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an image forming apparatus equipped with a print head according to the present invention, FIG. 2 is a perspective view of the main parts of the print head only, FIG. 3 is a detailed view thereof, and FIG. An end view of the main part, FIGS. 5(a) and (b). (c) is an explanatory diagram of a conventional example. 301: Casing, 304: LCD panel, AOS
: Liquid A armpit, 305: Lens array, 306:
Light emitting diode unit, 392: Mounting frame. Oni Figure 1 Rabbit Figure 2 Horse Figure 4 Figure 30e)

Claims (1)

[Claims] 1. A print head including a light source unit, a micro-shutter array that controls the light beam of the light source to either a light-blocking state or a light-transmitting state, and an optical signal from the print head that converts the light signal from the print head into an image. In an image forming apparatus for illuminating a holding member, the micro-shutter array is attached to a holding panel and a coupling optical member for forming an image of the pattern of the micro-shutter array on the image holding member to a casing to form an integrated unit, and the light source is further provided. An image forming apparatus comprising a unit removably attached to the casing. 2. The image forming apparatus according to claim 1, wherein the micro-shutter array is a liquid crystal shutter array. 3. In the statement of claim 1, the light source is a light emitting diode array light source comprising light emitting diode chips arranged in one or more rows and a condensing means for condensing the emitted light. image forming device.