JPH0453347B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical writing device using a vacuum fluorescent tube used in an optical printer, and particularly to an optical writing device using a vacuum fluorescent tube used in an optical printer, and in particular, an optical writing device in which a plurality of phosphor light-emitting dots are arranged diagonally in a plurality of rows inside the tube. The present invention relates to an optical writing device that dynamically drives a vacuum fluorescent tube.

[Conventional technology]

Printers can be divided into several types depending on their printing methods, and optical printers are non-impact printers with excellent printing speed.

This optical printer consists of a writing head section for writing a print pattern and an electrophotographic section for printing the written pattern on paper, and its outline is shown in FIG.

Here, 1 is a photoreceptor, such as a photoreceptor drum or a photoreceptor belt, which is rotating at a constant speed in the direction of the arrow in the figure.A charger 2 is provided around the photoreceptor drum 1 to uniformly charge the drum surface. An optical writing section 3 is provided for applying a light pattern to the surface of the photosensitive drum 1 to form a latent image. Also 4
is a developing section to which toner is attached depending on the charging state of the photosensitive drum 1. After the photosensitive drum 1 passes through this developing section 4, the paper 8 supplied from the cassette 7 is
Then, toner is applied by the transfer section 9 and transfer is performed. The charge remaining on the photosensitive drum 1 after the transfer is erased by the charge eliminating section 5, and the toner remaining after the transfer is further removed by the cleaning blade 6.

By the way, the writing section of this optical printer has conventionally been known as a type that uses a laser beam, a type that has light emitting diode (LED) dots arranged in an array, or a type that combines a liquid crystal (LCD) shutter cell with a light source. There is. Furthermore, recently, an optical writing unit using a vacuum fluorescent tube has been developed, which has a simple structure and has the advantage of being able to obtain a wavelength suitable for writing on a photosensitive drum.

Here, the laser beam type is capable of high-speed writing, but has the drawbacks of being mechanically complex, large, and expensive because it has mechanically movable parts. Types that use other LEDs, LCDs, or vacuum fluorescent tubes can be made smaller because they have no mechanically moving parts, but if you try to increase the resolution, you need to narrow the light emitting dot pitch. Furthermore, the number of light-emitting dots arranged increases depending on the size of the printing paper. Moreover, it is necessary to individually control the light emission of each of the light emitting dots arranged in large numbers. Therefore, if an attempt is made to statically drive an LED, LCD, vacuum fluorescent tube, etc., a drive circuit corresponding to the number of light emitting dots arranged is required, and there is also a problem in the number of lead wires and their processing.

In order to solve the above-mentioned problems in this kind of light emitting array type, a configuration has been considered in which two or more rows of light emitting dots are arranged and each light emitting dot is controlled by dynamic driving.

For example, what is shown in a plan view and a partial sectional view in FIGS. 7a and 7b is an example of this type of configuration using a vacuum fluorescent tube proposed by the present inventors.

Here, 11 is a substrate made of an insulating material such as glass, and a plurality of anode conductors (eight in the illustrated embodiment) 12 are arranged in stripes on this substrate 11.
is installed. Each anode conductor 12 is coated with a phosphor layer 13 in an oblique direction to form a light emitting dot.

On the other hand, 14 is a control electrode in which a slit 15 is formed in an oblique direction facing each phosphor layer 13 on the anode conductor 12, and each is electrically independent.
It is led out to an external terminal 16. Further, above the control electrode 14, a plurality of linear cathodes 17 that are heated and emit electrons are stretched and arranged, and these electrodes are connected to the side plate 1 sealed to the periphery of the substrate 11.
8 and a front plate 19 in an airtight container to form a vacuum fluorescent tube.

In the structure shown in FIGS. 7a and 7b, compared to static drive, the number of external terminals led out to the outside is
If you try to print at a resolution of 12 lines/mm on B4 size (effective print width 256 mm) paper compressed to about 1/8, for example, if you use static drive, 3072 light-emitting dots will be printed in a line. Array and 3072
It is necessary to control the light emission using the external terminal of the book.
In contrast, the structure shown in Figure 7 has 384 (3072/
8) With the number of terminals + 8 external terminals, 3072 light emitting dots can be controlled.

[Problems with conventional technology]

However, in order to dynamically drive a vacuum fluorescent tube having the structure shown in FIG. If adopted, the following problems arise.

First, the photosensitive drum 1 shown in FIG. 6 must be of a continuous rotation type due to mechanical requirements. Therefore, in order to ensure a printing speed above a certain level, the rotation speed of the photosensitive drum 1 cannot be slowed down, and it is necessary to write one line substantially parallel to the axis of the photosensitive drum. , the scanning period of the control electrodes 1, for example, 384 control electrodes must be scanned in an extremely short time. This means that the light emitting time of the light emitting dot itself is very short.
It becomes difficult to obtain the emission brightness necessary for writing.

In addition, in the case of control electrode scanning, there is also the problem that the order of transferring write data to the anode conductor becomes complicated.

[Means for solving problems]

As a result of various studies on the optimal driving method for vacuum fluorescent tubes with the above-mentioned dynamic drive structure, the present invention adopts a method in which the anode side is sequentially scanned and a write signal is applied to the control electrode in synchronization with the scanning of the anode. This solves problems such as brightness and write data transfer.

Therefore, in the present invention, a plurality of striped anode conductors are disposed on a substrate, and a plurality of striped anode conductors are disposed on a substrate, and a plurality of striped anode conductors are arranged diagonally across the anode conductor and facing the phosphor layer coated on the anode conductor. For a vacuum fluorescent tube having a plurality of electrically independent control electrodes in which slits are formed in the direction, an anode scanning unit that scans the anode conductor at a predetermined period; , and a write control section for applying a write signal to the control electrode.

[Effect]

Therefore, the height dimension of the light emitting dot (dimension in the direction perpendicular to the axis of the photosensitive drum) of the photoreceptor, for example, the photosensitive drum, facing the light emitting dot of the vacuum fluorescent tube is
The anode conductor is scanned once by the anode scanning section during the movement of the anode conductor. Then, by selectively driving the control electrode in accordance with the print signal in synchronization with the scanning of the anode conductor, a latent image is formed on the photosensitive drum using an example of the diagonally arranged light emitting dots as a printing unit. will be held.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of an optical writing device according to the present invention, and the portion indicated by the general reference numeral A schematically shows a vacuum fluorescent tube.

The electrode structure itself of this vacuum fluorescent tube A is the same as that of the dynamic drive type vacuum fluorescent tube shown in FIG. 7 described above, so parts having the same function are given the same reference numerals. That is, a plurality of anode conductors 12 (in this example, 8
a phosphor layer 1 on the anode conductor 12;
Apply 3. A control electrode 14 having a slit 15 defining the phosphor layer 13 is placed on the anode conductor 12 at a predetermined distance. 17 indicates a filament-like cathode.

Thus, the phosphor layer 13 is coated and each portion of the control electrode 14 divided through the slit 15 forms a respective light emitting dot. Further, the number of control electrodes 14 varies depending on the size of the target printing paper, the printing resolution, etc., but for example,
For B4 printing paper, 384 pieces are almost enough.
A resolution of about 12 lines/mm can be obtained. Therefore,
In the case of the embodiment shown in Fig. 1, the external terminals to be led out are (8 terminals for anode conductor) + (384 terminals for control electrode) +
(2 for cathodes) = 394, forming a vacuum fluorescent tube for dynamic drive.

By the way, in this case, in order to make the printed "line" continuous, the positional relationship of each light emitting dot may be selected as follows. That is, as shown in FIG. 1, if the row direction is the arrangement of the light emitting dots in the direction parallel to the anode conductor 12, and the column direction is the arrangement of the light emitting dots in the diagonal direction, then in the same column, as shown in FIG. As shown, when the corners C1 and C2 of the light-emitting dot in the row above are moved in parallel in the row direction by the dot interval Ps in the column direction,
Position it so that it matches the corners C3 and C4 of the lower row of light emitting dots. Also, the corners C1 and C2 of the light-emitting dots in the bottom row of each column are adjusted so that when they are translated upward by the number of rows of light-emitting dots, they match the corners C3 and C4 of the first light-emitting dot in the next column. By selecting the arrangement, printing as a continuous line segment becomes possible.

Furthermore, if the height of the luminescent dot is Ph,
The space Ps of the light emitting dots in the column direction is selected to be an integral multiple of the space Ps. In the embodiment shown in FIG. 2, Ph=
There is as Ps.

Furthermore, the shape of the light emitting dot is not limited to the diamond shape shown in FIG.
The shape of the slit 15 can be arbitrarily selected. FIG. 3 shows an example in which each light-emitting dot is square-shaped.

On the other hand, in FIG. 1, 21 is the anode conductor 1
2 is an anode scanning unit that generates a scanning signal for sequentially scanning the anode conductor 12 at a predetermined timing; This is a print control section. Furthermore, 23 is the anode scanning section 2
This is a timing circuit section that provides timing signals for scanning or driving to the printing control section 1 and the printing control section 22.

Next, the operation of the optical writing device of the present invention having the above-described configuration will be explained.

First, in the optical writing device of the present invention, the writing operation is performed using the time during which the photosensitive drum moves by the height Ph of the light emitting dot, that is, the dimension of the light emitting dot in the direction orthogonal to the axis of the photosensitive drum, as a unit of writing timing. conduct. This period of movement of the photosensitive drum is now defined as one field of writing, and each field is represented by T1 and T2 as shown in FIG.

Then, within this field period T1, the plurality of anode conductors 12 of the vacuum fluorescent tube A are scanned once.

However, in FIG. 4, the first field T1
Assuming that the scanning period of the anode conductor 12 in the inner region is t1, the anode scanning section 21 receives the timing signal shown in FIG. 4a from the timing circuit section 23, and scans the anode as shown in FIGS. The conductor 12 is sequentially scanned.

On the other hand, in accordance with the scanning of the anode conductor 12, the print control section 22 applies a print signal to the control electrode 14. Now, each light emitting dot shown in Fig. 1 is
As shown in the figure, D11, D12,...D1n, D2
1, D22...D2n...D81, D82...D8n, first, in the first field T1, while the anode conductor 12 in the first row is scanning (Fig. 4b), each control is performed according to the given print signal. A drive signal is applied to the electrode 14. That is, when scanning the anode conductor in the first row of the first field (FIG. 4b), the light-emitting dot D is generated in accordance with the print signal, as shown in FIG. 4j.
Lighting control of 11 to D1n is performed. When the next second row of anode conductors 12 is scanned (FIG. 4c), the lighting of the light emitting dots D21 to D2n is controlled as shown in FIG. 4J. Then, when the lighting of the light emitting dots D81 to D8n is controlled in the scanning of the eighth line in the first field T1 (FIG. 4i), the writing of the first field T1 is completed.

In this case, as described above, one field is a period in which the photosensitive drum moves by the height Ph of the light emitting dots, and since the photosensitive drum is continuously rotating during this period, the light emitting dots D11, D21, D3
1, D41, D51, D61, D71, and D81, when trying to print a straight line in the axial direction of the photosensitive drum, if viewed microscopically, it is somewhat inclined with respect to the axis. However, the height Ph of the light-emitting dot itself is about several tens to several hundred μm, and if the scanning period t1 is set smaller than the field period T1 shown in FIG. The deviation is slight and poses no practical problem.

Next, after the photosensitive drum has moved a distance Ph, it enters the second field T2, as shown in FIG. 4, where similar scanning is performed and a latent image is formed on the surface of the photosensitive drum.

The above-mentioned operation will be explained in more detail with reference to FIG. 5, which is a plan view of the surface of the photosensitive drum.

FIG. 5 shows an example in which the light-emitting dots are square, and for simplicity, printing is performed using four light-emitting dots D11, D12, D21, and D22. and,
The photosensitive drums are laid out flat and divided into sections and numbered (1, 1 to 4, 4) as shown by broken lines in the figure.

Therefore, if the photosensitive drum moves in the direction of the arrow B shown in the figure, then the row section (1,
1) to (1, 4) are moved by the height Ph of the light emitting dot, which corresponds to one field.

First, in the first field shown in Fig. 5a, the light-emitting dots D11 and D12 are turned on (in the developing section shown in Fig. 6, there are two types of development: reversal development in which toner is deposited on the area hit by light, and regular development in the opposite case). The lighting control of the light-emitting dots differs depending on the type of development, but here we will explain using reversal development as an example), and latent images are formed in sections (1, 1) and (1, 3). Ru. Next, in the second field (FIG. 5b), the sections (1, 1) to (1, 4) of the photosensitive drum move to the arrangement gap of the light emitting dots, but in this example, the line segments to be formed are In order to maintain continuity, the light emitting dots are scanned in this second field as well. That is, in this second field, the light emitting dot D11 is turned on to form a latent image in the section (2, 1).

In the subsequent third field shown in FIG. By lighting D22, sections (1, 2), (1, 4)
A latent image is formed at (3,1). Finally, in the fourth field shown in FIG.
It has moved to the row below D22, and a linear latent image parallel to the axis of the photosensitive drum has already been formed there. By lighting up the light emitting dots D11 in this fourth field, an "L" shaped pattern can finally be formed.

In this way, each time the photosensitive drum moves by a distance Ph corresponding to the height of the light emitting dot, the anode conductor 12 is scanned once according to the timing shown in FIG.
By driving the control electrode in accordance with the scanning of the anode conductor 12, it is possible to form a latent image in an arbitrary pattern on the photosensitive drum. Moreover, in this case, since the latent image formed on the photosensitive drum is obtained as a continuous line segment, this latent image is developed in the developing section 4 shown in FIG. This will result in printing that is extremely easy to see and has high print quality.

Incidentally, in the above-described embodiment, the scanning period t1 of the anode conductor is set short with respect to the period T1 of one field, but if the rotation of the photosensitive drum is somewhat slow, the period T1 of one field shown in FIG. Even if the period t1 required for one scanning of the anode conductor is approximately equal, the printing quality is hardly affected, and the periods T1, t1, etc. can be arbitrarily determined depending on the printing speed and the like. Further, the number of anode conductors and the number of control electrodes can be arbitrarily selected depending on the printing purpose.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications without changing the gist thereof.

〔effect〕

As described above, the optical writing device of the present invention has
A plurality of control electrodes each having a slit extending in a direction crossing the anode conductors arranged in a stripe pattern are provided, and a phosphor layer is applied onto the anode conductors that are visible from the control electrodes. Using a vacuum fluorescent tube as a light-emitting dot for writing, the anode conductor of the vacuum fluorescent tube is sequentially scanned, and while the photosensitive drum facing it moves by the height of the light-emitting dot, the above-mentioned process is performed. The configuration is such that one scan of the anode conductor is completed.

Therefore, it is essentially a dynamic drive, and even if the number of light emitting dots is increased to increase resolution or to accommodate larger printing paper sizes, the processing of external terminals and the increase in driver circuits can be suppressed. becomes possible.

Further, by appropriately selecting the number of anode conductors within a range of about 2 to 10, a large duty factor can be obtained. Therefore, there is an advantage that the brightness of each light emitting dot can be increased.

Furthermore, in the optical writing device of the present invention, a writing operation is performed on the photosensitive drum using a row of light-emitting dots arranged diagonally as a unit, but the order of scanning is the order in which the light-emitting dots are arranged in the column direction. This facilitates data serial/parallel conversion when transferring print data.

Furthermore, because the anode conductor is scanned once every time the photosensitive drum moves by the size of the light-emitting dot, the continuity of each line segment forming the print pattern is maintained, resulting in extremely easy-to-read and high-quality printing. is obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the optical writing device according to the present invention, FIG. 2 is a diagram for explaining the pattern arrangement of the same implementation area, and FIG. 3 is a block diagram showing an embodiment of the optical writing device according to the present invention. 4 and 5 are diagrams showing the main parts of other embodiments, and FIGS. 4 and 5 are diagrams for explaining the operation of the optical writing device according to the present invention. FIG. FIG. 7 is a diagram for explaining a vacuum fluorescent tube used in the present invention. A... Vacuum fluorescent tube, 12... Anode conductor, 13... Fluorescent layer, 14... Control electrode, D11 to D8n... Light emitting dots, 21... Anode scanning section, 22... Printing control section,
23...Timing circuit section.

Claims (1)

[Claims] 1. A plurality of striped anode conductors are arranged in the longitudinal direction of a substrate, and a control electrode having an opening facing the anode conductors is arranged diagonally to the arrangement direction of the anode conductors. a vacuum fluorescent tube section, which is arranged in a number greater than the number of anode conductors in the intersecting direction, and in which a phosphor layer is deposited on the anode conductors facing each opening of the control electrode to form a light emitting dot; an anode scanning section that scans the plurality of anode conductors of the vacuum fluorescent tube section once while a photoreceptor facing the light emitting dots of the vacuum fluorescent tube section moves a predetermined distance; and a print control section that applies a print signal to the control electrode. 2. The optical writing according to claim 1, wherein the anode scanning unit scans the plurality of anode conductors once while the photoreceptor moves by the size of the light emitting dot. Device. 3. The light emitting dots of the vacuum fluorescent tube section are such that the gap between each light emitting dot in the direction of movement of the photoreceptor is
3. The optical writing device according to claim 1, wherein the size of the light emitting dot is an integral multiple of the size of the light emitting dot. 4. The light emitting dots of the vacuum fluorescent tube section have an array structure that is continuous in a direction perpendicular to the photoreceptor movement direction by moving each light emitting dot in parallel by the arrangement pitch of the light emitting dots in the photoreceptor movement direction. Claim 1 characterized in that
2. The optical writing device according to item 2, item 3, or item 3.