JPS6165217A - Optical printing device - Google Patents

Abstract

PURPOSE:To improve print quality by providing plural lenses which form an image of light from light emitting segments of respective dot array fluorescent tubes on the surface of a photosensitive body. CONSTITUTION:An AC voltage is supplied to the filament 25 of a dot array fluorescent tube 11 to heat the filament, which emits a thermoelectron. A voltage is applied between a grid electrode 23 and an anode electrode 18 and then a light emitting segment 20 emits light. A driving voltage is applied to respective anode electrodes 18 selectively according to print information and necessary segments 20 emit light to print the information. Plural dot array fluorescent tubes 11 are arranged zigzag in a main scanning direction while shifted in a subscanning direction, and plural image forming lens 34 which reduce and form an image of light from the light emitting segments 20 on the photosensitive drum 1 are provided. Thus, the dot size of the light emitting segments 20 is increased and the quantity of light is increased to improve light utilization efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION Background This invention relates to an optical printing device that uses a dot array fluorescent tube as an optical writing device.

BACKGROUND ART In recent years, electrophotographic optical printing devices (hereinafter also referred to as optical printers) that record output from computers, etc., have been constructed using dot array fluorescent tubes as optical writing devices that convert the output into optical signals. .

In such an optical printer, a single dot array fluorescent tube is provided in which a large number of light emitting segments are lined up to emit light selectively according to print information, and the light emitted from each light emitting segment of this dot array fluorescent tube is collected. A 1-magnification imaging element made of a photosensitive optical fiber lens or the like condenses the light and irradiates it onto the surface of the photoreceptor to form an electrostatic latent image in accordance with the printed information.

However, when a same-magnification imaging element is used in this way, the wide emission spectrum width of the dot array fluorescent tube causes a decrease in resolution due to chromatic aberration, and the shallow depth of focus causes blurring of the photoreceptor imaging surface. Furthermore, since the 1-magnification imaging element is close to the surface of the photoreceptor, toner adheres and becomes dirty, causing unevenness in the image, making it impossible to obtain sufficient print quality.

Purpose This invention has been made in view of the above points, and an object thereof is to improve the printing quality of an optical printing device.

Structure-1 In order to achieve the above object, the present invention is provided with a plurality of dot array fluorescent tubes and a plurality of lenses that image the light emitting segments of each dot array fluorescent tube on the surface of a photoreceptor.

Hereinafter, a detailed explanation will be given based on one embodiment of the present invention.

FIG. 1 is a schematic configuration diagram showing an example of an optical printer embodying the present invention.

In this optical printer, the photoreceptor drum 1 is rotated in the direction of arrow P when printing is started, and the surface of the photoreceptor drum 1 is uniformly charged by the charger 2.

Then, each light emitting segment of each dot array fluorescent tube of the optical writing device B, which is composed of a plurality of dot array fluorescent tubes arranged in a direction perpendicular to the rotational direction of the photoconductor drum 1 (main scanning direction), is emitted according to the printing information. The light emitted from each dot array fluorescent tube of this optical writing device B is irradiated onto the photoreceptor drum 1 through a plurality of lenses 4 arranged in the main scanning direction. An electrostatic latent image is formed thereon according to the printed information.

Thereafter, the electrostatic latent image on the photoreceptor drum 1 is transferred to a developing device 5.
A developer is applied thereto to visualize the image and transfer it to the recording paper 7 fed by the transfer charger 6.

Then, this recording paper is passed through a fixing device (not shown), subjected to a fixing process, and then discharged to an external paper output tray, etc. After the residual charge on the photosensitive drum 1 is erased by a static elimination lamp 8, the remaining developer is removed. It is removed by cleaner S and prepared for the next recording process.

Next, the dot array fluorescent tube constituting the optical writing device 3 in this optical printer will be explained with reference to FIGS. 2 and 3.

This dot array fluorescent tube 11 is mounted on a face glass 1 via a spacer glass 13 on a substrate 12 made of glass or the like.
4 is placed to form a vacuum container 15. Note that these glasses are usually bonded using low melting point glass.

A transparent electrode film is formed on the inner surface of the face glass 14 in order to prevent the influence of external electric fields and to prevent disturbance of electric field distribution due to charging of the surface by thermionic beams.
A cathode potential or a grid potential is applied to this transparent electrode film on the first day.

And on the substrate 12 inside the vacuum container 15.

Anode electrodes 18 are arranged in a row in the longitudinal direction of the vacuum container 15.

At the tip of the positive electrode 18, light emitting segments 20 in the form of minute dots formed by applying dot-shaped phosphor are arranged in a line.

The anode electrode 18 is formed by photoetching a metal thin film such as Aif' on the substrate 12, and high resolution can be achieved by forming the anode electrode 18 in this manner.

Further, the positive #@ electrodes 18 extend alternately (in a staggered manner) on both sides of the outside of the vacuum container 15, and are connected to a drive IC (not shown) by wire bonding or the like.

Furthermore, the main component of the phosphor 1 is zinc oxide ZnO doped with, for example, Zn.

The portion of each anode electrode 18 other than the phosphor IS is covered with an insulating paste layer 22 made of low melting point glass formed by a thick film printing method, and on this insulating paste layer 22, a thin metal film is formed. A grid electrode 23 having a mesh structure is provided.

Note that this grid electrode 23 is made of insulating paste) 12
It may be formed directly on 2 by vapor deposition or the like, or it may be formed by a thick film printing method.

Moreover, this grid electrode 23 has one light emitting segment 20.
The slits 2B are formed corresponding to the rows of 2 grids, so that the light emitted from each minute light emitting segment 20 can be formed into two grids. l1t
This prevents it from being blocked by I2B, improves the effectiveness of the emitted light, and suppresses variations in the brightness of the emitted light.

Above the grid electrode 23, there is one light emitting segment l.
A filament (cathode electrode) 25 formed by applying an oxide to a thin tungsten wire along the direction in which the contacts 20 are arranged.
are tensioned by supports 26 and 26, and the spring parts +, +2
7.27 is applied with tension.

By connecting a driving IC to the tondo array fluorescent tube 11 configured in this way, the optical writing device 3
is configured.

In the dot array fluorescent tube 11 constructed in this way, thermoelectrons are emitted by heating the filament 25 by supplying an alternating current voltage of, for example, 1O to 20V.

At this time, by applying a voltage of, for example, +20V to the grid electrode 23 and a voltage of, for example, +40V to the anode electrode 18, the thermoelectrons are accelerated by the grid electrode 23 and hit the phosphor IS, and the phosphor The light-emitting segment 20 of the light-emitting segment 20 emits light.

At this time, the emission spectrum when the phosphor is ZnO:Zn has a peak at 505 nm as shown in FIG. 4, and has a wide characteristic of 410 nm on the short wavelength side and 650 nm on the long wavelength side.

Therefore, by selectively applying a driving voltage to each anode electrode 18 according to print information, it is possible to cause the required light emitting segments 20 to emit light and print.

In this optical printer, as shown in FIG. 5, a dot array fluorescent tube 11 (optical writing device 3)
A plurality of dot array fluorescent tubes 11 are arranged in a row in the main scanning direction, and a plurality of light emitting segments 20 of the dot array fluorescent tubes 11 are enlarged and imaged on the photoreceptor drum 1 between each dot array fluorescent tube 11 and the photoreceptor drum 1. An imaging lens 4 is arranged.

In this case, it is necessary to form one line of dot images at equal intervals on the photoreceptor drum 1, so the dot images between each dot array fluorescent tube 11 are optically arranged at equal intervals on the photoreceptor surface. connected to.

As described above, this optical printer is provided with a plurality of dot array fluorescent tubes and a plurality of lenses that image the light emitting segments of each dot array fluorescent tube on the photoreceptor surface.

This eliminates the reduction in resolution due to chromatic aberration caused by the wide emission spectrum of dot array fluorescent tubes, resulting in higher resolution than when a 1-magnification imaging element is used to image the light-emitting segments onto the photoreceptor surface. This enables a deep depth of focus, which prevents image blurring due to blurring of the photoconductor surface, and because the lens can be placed far enough away from the photoconductor, toner stains do not occur and uneven light intensity occurs, allowing printing. Quality improves.

In addition, by dividing the dot array fluorescent tube into multiple pieces, it is possible to perform divided driving, which was difficult with a single dot array fluorescent tube with high density (10 to 12 dots/inch) due to crosstalk occurring at the dividing point. is possible, IF
The number of A-motion ICs can be reduced, the configuration becomes simpler, and costs are reduced.

FIG. 6 is a block diagram of main parts showing another embodiment of the present invention.

In this embodiment, a plurality of dot array fluorescent tubes 11 are arranged in a staggered manner in the main scanning direction with their positions aligned in the sub-scanning direction (rotation direction of the photoreceptor), and each dot array fluorescent tube 11 is arranged in a staggered manner in the main scanning direction.
1), several M imaging lenses 34 are arranged to form a reduced image of the light emitting segment 20 of each dot array fluorescent tube 11 on the photosensitive drum 1.

Note that even when using a reduction optical system in this way, it is sufficient to set the dot density of the dot array fluorescent tube 11 in advance in accordance with the dot density on the imaging plane, and also to The above dot images can be joined optically in the same manner as in the above embodiment.

With this embodiment, in addition to the effects of the above embodiment, since a reduction optical system is used, the dot size of the light emitting segment (light emitting dot) of the dot array fluorescent tube can be increased, and the amount of light can be increased. , the light usage efficiency is improved.

For example, if an optical system with a reduction magnification of 1/2 is used, the dot size can be doubled compared to the same magnification, and since the dot area is quadrupled, the amount of light is also quadrupled.

FIG. 7 is a schematic plan view of a dot array fluorescent tube in still another embodiment of the present invention.

The driver 1 to the array fluorescent tube 41 have a face glass 44 placed on the base Fj 42 via a spacer crow 43 to form one vacuum container 45 having the size of one line.

Then, on the substrate 42 in the vacuum container 45, light emitting segments 50 in the form of minute dots, which are formed by applying a dot-shaped phosphor to the tip of the anode electrode, are divided into segment groups of a predetermined number and arranged in a line. However, a plurality of grid electrodes 53 are provided corresponding to each segment group.

Note that a filament 55 is provided above the grid electrode 53.
It is upholstered.

Further, the other configurations of this dot array fluorescent tube 41 are the same as the dot array fluorescent tube 11 shown in FIGS. 2 and 3, so a description thereof will be omitted.

In other words, this dot array fluorescent tube 41 has a plurality of dot array fluorescent tubes substantially formed in a row in one vacuum container (fluorescent tube) by dividing the grid electrode into a plurality of pieces, that is, as shown in FIG. A plurality of dot array fluorescent tubes arranged as in the example are assembled into one vacuum container.

Therefore, when using this dot array fluorescent tube 41, a magnifying optical system is used to image each light emitting segment on the photoreceptor surface as in the embodiment shown in FIGS. 1 to 5. good.

By configuring the dot array fluorescent tube in this way,
In addition to improving printing quality, it is possible to integrate common parts of multiple dot array fluorescent tubes, making it possible to reduce costs and reduce the size of the printer. By ensuring a sufficient interval between the two, crosstalk will not occur even if divided driving is performed.

FIG. 8 is a schematic plan view showing a dot array fluorescent tube in still another embodiment of the present invention.

Similar to the dot array fluorescent tube 41 of the above embodiment, this dot array fluorescent tube 61 has a micro dot light emitting segment 70 formed by applying a dot-shaped phosphor to the tip of the anode electrode in one vacuum vessel 65. It is divided into segment groups of a predetermined number and arranged in two rows in a staggered manner, and a plurality of grid electrodes 73 are provided in a staggered manner corresponding to each segment group.

Note that three filaments 75 are stretched above the grid electrode 73.

The other configurations of this dot array fluorescent tube 61 are the same as those of the dot array fluorescent tube 11 or 41 described above, so a description thereof will be omitted.

In other words, this dot array fluorescent tube 61 has a plurality of dot array fluorescent tubes substantially formed in two rows in one vacuum container (fluorescent tube) by dividing the grid electrode into a plurality of pieces and arranging them in two rows. That is, a plurality of dot array fluorescent tubes arranged as in the example shown in FIG. 6 are grouped together in one vacuum container.

Therefore, when using this dot array fluorescent tube 61, a plurality of imaging lenses are arranged in a staggered manner corresponding to each dot array fluorescent tube as shown in FIG. All you have to do is form a reduced image.

In this way, in addition to the effects of the embodiment shown in FIG. 5, effects such as cost reduction and compactness can be obtained.

As explained above, according to the present invention, the printing quality in an optical printing device is improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of an optical printing device embodying the present invention. 2 and 3 are a schematic plan view and a schematic side view showing an example of the dot array fluorescent tube, and FIG. 4 is a diagram showing an example of the emission spectrum of the dot array fluorescent tube. FIG. 5 is a configuration diagram showing the arrangement of the dot array fluorescent tube and the imaging lens. FIG. 6 is a block diagram of main parts showing another embodiment of the invention, and FIG. 7 is a schematic plan view showing a dot array fluorescent tube in still another embodiment of the invention. FIG. 8 is a schematic plan view showing a dot array fluorescent tube in yet another embodiment of the invention. FIG. S is a configuration diagram showing the arrangement of the dot array fluorescent tube and the imaging lens. 1... Photosensitive drum 4.34... Imaging lens 1
1.41.61... Dot array fluorescent tube 20, 50.
70...Light emitting segment Fig. 1 Fig. 2gI Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 blJ b! b 4j 50 Figure 8 Figure 9 procedural amendment (white side November 13, 1982)

Claims (1)

[Claims] 1. A light comprising a plurality of dot array fluorescent tubes each having a large number of light emitting segments arranged in a row, and a plurality of lenses for imaging the light emitting segments of each dot array fluorescent tube on a photoreceptor surface. Printing device.