JPS63221762A - Drive method for plasma discharge type optical head - Google Patents

Abstract

PURPOSE:To attain high speed and high resolution of a printer by devising adjacent electrode blocks in a way that other electrode block is not driven while one electrode block is driven so as to mis-lighting due to crosstalk. CONSTITUTION:Electrodes in total m-set at an interval of 2n-set are connected in common among M-set of individual electrodes corresponding to M-set of plasma elements in total and the m-set of plasma elements are selectively lighted in the same timing. On the other hand, one common electrode is assigned to n-set of individual electrodes to constitute plural common electrodes, and the common electrodes are divided into odd/even order number common electrode groups and drive circuits corresponding to each are provided. In case of writing a data to one drive circuit section, the write of other data is subjected to inhibition control and the drivers of the inhibited side are all turned off. Thus, mis- lighting due to crosstalk is prevented.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for driving an optical head used in electrophotography, and is particularly concerned with a method for driving an optical head used in electrophotography. The present invention relates to a method of driving an optical head.

(Prior Art) Light-emitting elements that utilize plasma discharge light emission of discharge gas have been known. Further, as an application example of such a plasma light emitting device, there is a plasma display panel (hereinafter sometimes referred to as FDP), which is constructed by using a large number of display pixels arranged two-dimensionally. . This type of PDP is called CRT (Cathode Ray Tube).
It is expected to be used as a replacement display for F.
I will briefly explain DP.

PDPs are roughly divided into two types, AC-type PDPs and DC-type PDPs, depending on their driving methods. Although they have some structural differences, they all agree in that they usually emit IIi electroluminescence through matrix drive.

In the most typical PDP structure, one substrate has a cathode group made up of a plurality of cathode electrodes arranged in parallel, and the other substrate has an anode electrode group made up of a plurality of anode electrodes arranged in parallel. The substrates are bonded together so that the electrode forming surfaces face each other and the cathode and anode electrodes intersect with each other so that an encapsulation region is formed between the two substrates. This region is filled with any suitable discharge gas, such as an inert gas at a suitable pressure. Furthermore, suitable drivers are connected to the anode and cathode electrodes, respectively.

When performing matrix driving with an FDP having such a configuration, a data signal is supplied to the driver connected to the anode electrode, and a selection signal is supplied to the driver connected to the cathode electrode.

Each of these signals is synchronized by a clock signal.

FIGS. 6A and 6B are time charts schematically showing an example of a method for driving the PDP to emit and extinguish light using the above-described data signal and selection signal. Figure 6 (
A) is a waveform diagram showing a data signal, and FIG. 6(8) is a waveform diagram showing a selection signal.

In a PDP, light is emitted when the potential difference between the opposing cathode electrode and anode electrode exceeds the plasma discharge starting voltage e+, and the light emission stops when this potential difference becomes smaller than the discharge sustaining voltage e2. Therefore, for the voltage E that indicates writing applied to the anode electrode, E Eo<ez deka')
Bias voltage E such that E o O < e 2. This bias voltage E is set in advance. is set as the common potential of the data signal and selection signal. Under these conditions, the potential of the cathode electrode to be selected is set to O,
When a data signal of voltage E indicating writing is supplied to the anode electrode opposite to the selected cathode electrode,
Since the potential difference between the cathode and anode electrodes becomes larger than e, the pixel composed of these electrodes emits light. In FIG. 8, a light emitting state is obtained in a time period from time t to time tb.

By the way, plasma discharge light emission has characteristics such as the wavelength band of emitted light changing depending on the composition of the discharge gas used. Therefore, if this PDP% electrophotographic system could be applied to, for example, an optical head of a printer, it would be convenient because it would be possible to easily configure an optical head that matches the wavelength sensitivity characteristics of the photoreceptor included in this equipment. be.

For example, when a PDP is applied to an optical head of an electrophotographic printer, a large number of plasma light emitting elements are arranged in a line on a predetermined substrate so as to correspond to the width direction of the photoreceptor (corresponding to the main scanning direction). In this case, the resolution of the optical head is generally required to be higher than that of the display. Therefore, the packaging density of the plasma light emitting elements may be changed depending on the required resolution.

In the optical head configured in this way, each light emitting element arranged in the main scanning direction is
! As described above, the light is emitted and extinguished according to the balance between the data signal and the selection signal, and as a result, one line of electrostatic latent image can be formed on the photoreceptor. Roughly speaking, after this photoreceptor is moved in the sub-scanning direction, each light emitting element in the main scanning direction is driven again as described above, and by repeating these processes, a two-dimensional electrostatic charge is generated on the photoreceptor. A latent image can be formed.

However, it is desirable for printers to be able to print in a practically short time and to have good quality prints as a result. In order to satisfy this requirement, it is preferable that the time required to finish driving each light emitting element arranged in a line, that is, the main scanning time, is shorter, and that the packaging density of the light emitting elements is higher.

However, when setting the preferable conditions as described above, it is necessary to consider the following.

Assuming that the main scanning time is a certain period of time, if the number of light emitting elements provided in this optical head is increased in order to improve resolution, the driving time per - light emitting element will naturally become shorter. However, in the electrophotographic method, in order to form an electrostatic latent image, it is necessary to supply enough light 1 to selectively electrostatically neutralize a part of the photoreceptor to the corresponding part of the photoreceptor. Therefore, it is necessary to ensure a certain driving time per - number of light emitting elements.

Unless these mutually contradictory requirements are satisfied, it will not be possible to provide a printer that is capable of higher resolution, higher speed printing, and at a lower price. Various studies were conducted. the result,
Roughly speaking, if you use an optical head configured as described below and drive this optical head using a certain driving method,
It has been found that both of the contradictory matters mentioned above can be satisfied.

This will be explained below with reference to FIG. 7 and FIGS. 8(A) to 8(D).

First of all, such an optical head has a plurality of electrode plates each having a plurality of individual electrodes (for example, a cathode electrode) assigned to each of a plurality of common electrodes (for example, an anode electrode) arranged in a line. This is a plasma discharge type optical head that includes a plasma discharge type optical head. FIG. 7 is a plan view of essential parts of an example of such a plasma discharge type optical head, mainly showing its electrode structure.

The optical head shown in FIG. 7 includes a plurality (eg, m) of common electrodes 17 and a plurality (eg, N) of individual electrodes 15 assigned to each common electrode. Further, in this optical head, the common electrode 17 is constituted by an electrode block 19 as a basic unit. Further, the region where each common electrode and each individual electrode face each other (the region marked with diagonal lines and marked 18 in FIG. 7) becomes an individual plasma light emitting element. Therefore, an optical head is constructed in which a large number (for example, M pieces, where M>>N) of plasma light emitting elements are arranged in a line.

Also, each common electrode 17 (in this case, 3 out of many common electrodes)
Only 1 A + , A 2 , and A 3 are shown. ) is a common electrode driver (not shown)
are connected to each. The individual electrodes of each block are also connected to a driver (not shown) for driving the individual electrodes, or this connection is made in this case as explained below. In the following description, the N individual electrodes in each block will be referred to as the first to Nth individual electrodes from the same end of each block.

The first individual electrodes of each block (C++.

C21, C31-), the second individual electrodes of each block (CI2.C22, C3□...), ...
・, between the Nth individual electrodes of each block (C+-, C
27, C3, , "") are connected to each other, the multi-wiring 21a is configured. Each of the wirings 21.1 to 21.1 of the multi-wiring 21a is connected to a driver for driving an individual electrode.

By driving such a plasma discharge type optical head in the manner described below, both of the above-mentioned contradictory matters can be satisfied.

The voltage application conditions for causing each light emitting element provided in the optical head to emit or extinguish light are determined by the method already explained using FIG. 6.

The individual electrode driver (not shown) connects the multi-wiring 21.
~21. l, versus Snake. A selection signal that changes from volts to O volts is supplied time-sequentially in response to, for example, a clock signal φ. FIGS. 8(B) to (D) are time charts showing how such selection signals are supplied, and FIG.
B) is multi-wiring 2I.

FIG. 8(C) is a waveform diagram showing the selection signal supplied to the multi-wiring 211□,
FIG. 8(D) is a waveform diagram showing the selection signal supplied to the multi-wiring 21°. As is clear from these figures,
The voltage state of each individual electrode in each block is E. It changes sequentially from 0 to 0 for a certain period of time.

On the other hand, for the data write signal, n multi-wirings 21, to 21□ connected to the individual electrode driver
It can be seen that it is sufficient to supply data write signals corresponding to the individual electrodes that are in the selected state to the respective common electrodes.

n multi-wirings 21 connected to individual electrode drivers
．． 1-21. , are selected sequentially, so the data write signal is divided into n times and supplied to the common electrode.

FIGS. 8(A) to 8(D) are signal waveform diagrams showing this state. For example, in the time period from time t to time t2, the data write signal for the first individual electrode of all blocks is It is shown that the voltage is supplied to each common electrode.

Here, it is assumed that the time to finish driving all M light emitting elements provided in the optical head according to the print data, that is, the main scanning time is, for example, 1 second. In such a case, in the general method of driving M light emitting elements one by one, the driving time of one light emitting element is T/M seconds.

On the other hand, when the above-mentioned optical head is used for parallel driving as described above, M light emitting elements are arranged in a plurality of blocks (
For example, the light emitting elements in the m blocks can be driven in parallel in the m blocks in time sequence. Therefore, if the main scanning time remains the same as tT, the driving time of - number of light emitting elements! m-T/M, and therefore, it is possible to lengthen fl during driving (light emission) per - number of light emitting elements. Also, if the driving time of - light emitting elements is changed as before, the main scanning time @ T / m
It is also possible to shorten it to Roughly speaking, even if the number of light emitting elements is increased to, for example, 2M to form an optical head, the driving time of each light emitting element remains long for the above-mentioned reasons, and printing with high resolution can be obtained.

In this way, the above-described parallel driving method makes it possible to secure a practical printing time.

(Problems to be Solved by the Invention) However, this parallel driving method has a problem in that as the resolution of the optical head progresses, erroneous light emission may occur depending on the signal state supplied to the optical head. The occurrence of this erroneous light emission will be explained with reference to FIG.

At a certain time txtt=J, the write signals supplied to the common electrodes indicated by A, A2, and A3 indicate extinction, light emission, and extinction, that is, the EQ shown in FIG.
E and E. Consider a case in which the signal is in a voltage state of , and individual electrodes indicated by CI+, C21, and C31 are selected in each electrode block. In this case, originally C
Only the light emitting elements corresponding to the individual electrodes 2 and 2 should emit light. However, if the distance between adjacent common electrodes (dimension indicated by S in FIG. 7) is reduced in order to increase the level of mounting ability of light emitting elements in order to obtain a high-resolution printer,
An individual electrode that is close to a block to which a light emitting signal is supplied and whose voltage state is 0 port, that is, a light emitting element corresponding to the individual electrode indicated by C31, is affected by crosstalk. This may cause erroneous flashing. Also, a write signal similar to this example is A1.
When individual electrodes supplied to the common electrodes A2 and A3 and indicated by GIn+C2n and C3n are selected, the light emitting element corresponding to C1n emits light incorrectly for the same reason.

Such erroneous light emission causes deterioration of printing quality, erroneous printing, and the like.

The present invention has been made in view of the above points, and therefore, an object of the present invention is to drive a plurality of electrode blocks in parallel as described above in order to cope with higher speed and higher resolution of printers, ll5lH to each other! An object of the present invention is to provide a method for driving an optical head that does not cause erroneous light emission even when the distance between common electrodes becomes very small.

(Means for solving the problem) In order to achieve this object, according to the present invention, a plurality of electrode blocks are allocated to each of a plurality of common electrodes arranged in a line. When driving a plasma discharge optical head including electrode blocks, the even-numbered and odd-numbered electrode blocks are driven alternately, and during this driving, the even-numbered electrode blocks are driven simultaneously with each other and the odd-numbered electrode blocks are driven simultaneously with each other. It is characterized by being driven.

(Function) According to the method for driving a plasma discharge optical head of the present invention, when focusing on adjacent electrode blocks, during the time period in which one electrode block is being driven, the other electrode block is not driven. become.

(Example) Below, Drawing 18. With reference to the drawings, an embodiment of a method for driving a plasma electrolytic optical head according to the present invention will be described. It should be noted that the drawings used in the following explanation are merely illustrative to the extent that the present invention can be understood, and the dimensions, shapes, and arrangement of each component are not limited to the illustrated examples. It should also be understood that identical components in these figures are designated by the same reference numerals. Further, the same components as those already explained are indicated by the same reference numerals.

In driving a plasma discharge optical head including a plurality of electrode blocks in which a plurality of electrode blocks are assigned to each of a plurality of common electrodes arranged in a line, even-numbered and odd-numbered electrodes are This method is characterized in that the blocks are driven alternately, and during this driving, even-numbered electrode blocks are driven simultaneously and odd-numbered electrode blocks are driven simultaneously with each other, but before explaining this method, First, an example of the configuration of a plasma discharge type optical head suitable for implementing the driving method of the present invention will be described with reference to FIGS. 1 and 2. FIG.

Light 12! 1 and 2 are a plan view and a perspective view of a main part mainly showing the electrode structure of a plasma discharge type optical head suitable for carrying out the driving method of the present invention.

1 and 2, 11 and 13 indicate the first and second substrates, respectively, which are sealed to each other with a suitable interval 9, and a discharge gas is filled in the gap between these substrates. . In addition, in order to generate plasma discharge from this discharge gas,
In this embodiment, the second substrate 13 has a plurality of (for example, two
m common electrodes 17 (for example, anode electrodes) are provided in a line so as to correspond to the width direction of the photoreceptor.

Further, the first substrate 11 has a plurality of electrodes (for example, n electrodes) for each of the plurality of common electrodes 17 provided on the second substrate 13.
A large number (for example, M, M>>n) of individual electrodes 15 are assigned such that individual electrodes (for example, cathode electrodes) of
is provided. 2m electrode blocks 19 are constructed using the common electrode 17 as a basic unit. In addition, in Atsushi 1, a part of the 2m electrode blocks 19, 5 electrode blocks 19a to 19e, are shown.

In this optical head, the area where each common electrode and each individual electrode face each other (the area marked with diagonal lines and numbered 18 in FIG. 2) becomes an individual plasma light emitting element. Therefore,
This optical head has M plasma light emitting elements arranged in a line.

Note that each common electrode 17 is connected to a common electrode driver (not shown). Further, the individual electrodes of each block are connected to an individual electrode driving driver (not shown), and in this case, the individual electrodes are connected as described below.

In the following description, the n individual electrodes in each block will be referred to as the first to nth individual electrodes from the same end of each block.

The first individual electrodes of every other block among the plurality of electrode blocks, for example, the blocks 19a, 19c, and 19e (these are referred to as odd-numbered blocks), and the electrodes of each of the odd-numbered blocks The first multi-wiring 31a (31g+ to 31..l) is connected so that the second individual electrodes are connected to each other, and the n-th individual electrodes of each odd-numbered block are connected to each other. Configure (first
(see figure), each wiring 311 to 3 of the first multi-wiring 31a
□ is connected to, for example, a first individual electrode driver (not shown).

On the other hand, 19b among the plurality of electrode blocks.

+9 (every other flock indicated by l, that is, the first individual electrodes of each even-numbered block, the second individual electrodes of each even-numbered block, etc.)
, the second multi-wiring 31b (31
b+~4bn) (see Figure 1). Each wiring 31, - 31, 2 of the second multi-wiring 31b is connected to, for example, a second individual electrode driver (not shown).

FIG. 3 is a block diagram showing an example of an optical head driving circuit suitable for carrying out the driving method of the present invention, including connections between the above-mentioned optical head and each driving driver.

In FIG. 3, reference numeral 51 indicates each wiring 31. of the first multi-wiring described above. ~31. ．． ．． 53 represents a first individual electrode driving driver to which is connected, and 53 represents a second individual electrode driving driver to which each wiring 31b, to 31b1 of the second multi-wiring described above is connected. The first individual electrode driver 51 and the second individual electrode driver 53 are connected to a counter decoder 55, respectively.

Further, 61 is the common electrode of each odd-numbered electrode block +7.
, -17° indicates the first common electrode drive driver to be connected, and 63 indicates the common electrode 1 of each even-numbered electrode block.
7° to 17° are connected to the second common electrode driving driver. A shift register 65 having a latch function is connected to the first common electrode driver 61. A shift register 67 having a latch function is connected to the second common electrode driver. In the M3 diagram, φ5 and φ2 indicate clock signals, and O□, D,
b indicates a data signal, and L indicates a crawl/Sochi signal.

Next, an embodiment of a method for driving a plasma discharge type optical head will be described using an example using the driving circuit shown in FIG. Note that FIGS. 4(A) to 4(F) show timing charts on the common electrode side of the drive circuit shown in FIG. 3, and FIGS.
(G) shows a timing chart on the individual electrode side.

The counter decoder 55 sequentially performs a walking operation and a decoding operation in response to the clock signal φ1, and outputs the output terminal Cs;
32, . The output from this counter decoder 55 is input to individual electrode driving drivers 51 and 53. The individual electrode driving drivers 51 and 53 set the corresponding output terminal voltage to O volts when the input signal is at a high level, and set the corresponding output terminal voltage to E0 volts when the input signal is at a low level. Therefore, the multi-wirings 31a+t 31b+, which are connected to the output terminals of the individual electrode driving drivers 51.53,
31-2.31bz, =”, 31.l,.

31b+, 0 volt is sequentially output. Here, it is connected to the output terminals of the individual electrode driving drivers 51 and 53.
le v le chi distribution a31. +------31bl, lct,
As explained in Figure 1, each of the M individual electrodes corresponding to a total of M plasma elements is connected to a total of m every 2n electrodes. The individual electrodes of the plasma elements become 0 port potential at the same timing, allowing for selective lighting. Therefore, m
Turning on or off of these plasma elements can be controlled by applying voltage to the common electrode corresponding to each plasma element.

Next, a method of controlling voltage application to the common electrode will be explained.

In the case of this embodiment, the common electrode drive circuit section includes a first common electrode drive circuit section for driving odd-numbered common electrodes, and a second common electrode drive circuit section for driving even-numbered common electrodes. The explanation will be given as a two-system configuration with a driver circuit section.

The first common electrode drive circuit section includes an m-hit shift register 65 with a latch circuit and a first common electrode drive driver 6.
1, and the second common electrode drive circuit section consists of an m-bit shift register 67 with a latch circuit and a first common electrode driver 63.

T7, T2, axis..., T2 in Fig. 4 (A) to (F)
．． , a data write signal is input to the input terminal of one of the m-hit shift registers 65 and 67 with a latch circuit in synchronization with the clock input φ2, and the data write signal is input to the input terminal of the other shift register at each timing of . This is 0 where "O" level is written, for example T1.
At the timing T2, the input terminal of the m-bit shift register 65 is input, and at the timing T2, the m-bit shift register 6
7 input terminals (to which data write signals are respectively input).

This state is shown in FIGS. 4(B) and 4(C). After the m-bit data write signal is input to either one of the shift register parts of the shift register with latch circuit 65 or 67, it is input to the Ls input signal terminal. When the latch signal Ls is input, the information of the shift register section mentioned above is latched into the latch section, and based on this information, the corresponding driver in the common electrode drive driver corresponding to this latch section is controlled to be on/off. .

Here, the aforementioned shift register with latch circuit 65.6
The input signal D Saz D Nb to the input terminal 7 is “○
”, the driver is off, that is, Eo volts (
(see Figure 6), the driver operates in an on state, that is, outputs E volts (see Figure 6) when the input signal is "1". For example, from time t1 to t2
During the period, the first common electrode driver 61 is turned on.
The second common electrode drive driver 6 enters the off-drive state.
All drivers of 3 are turned off. Moreover, in the period from time t2 to t3, conversely, the first common electrode driver 6
All drivers 1 are turned off, and the second common electrode driving driver 63 is turned on and off. Thereafter, the above-described state is alternately repeated from time j2n-1 to t2n in the same manner.

Here, each timing period of T2, T4, . . . , T2n is divided into n multi-wirings 310, .
31.6 is set to be the same as the timing period to sequentially put the O volt state, the corresponding mxn
It is possible to control each plasma element to turn on or off.

Similarly, each timing period of T3, 6, . . . , T2n-1 is set to
Or n multi-arrays connected to this! j+ 3+ b
＋、・・・・・・31、ヲSequentially ○ By keeping the timing period the same as the port state, the remaining m
It is possible to control xn plasma elements to turn on or off.

As explained in detail above, in the above embodiment,
On the individual electrode side, 2n @ individual electrodes are connected to the same multi-wiring, and the 2n multi-wirings are connected to 2n driving drivers, and these drivers are sequentially selectively driven.

On the other hand, on the common electrode side, one common electrode is assigned to n individual electrodes to form a plurality of common electrodes, and these common electrodes are further divided into odd-numbered and even-numbered common electrode groups. A drive circuit section corresponding to the common electrode group is provided, and when data is written to one drive circuit section, data writing to the other drive circuit section is prohibited, and the drive circuit section on the side where data is written is controlled. On/off control is performed on the drive driver of the drive circuit section, and all the drive drivers of the drive circuit section on the side where data writing is prohibited are turned off. Therefore, the odd-numbered and even-numbered electrode blocks can be driven alternately, and roughly speaking, during this driving, the odd-numbered electrode blocks are driven simultaneously with each other, and the even-numbered electrode blocks are also driven simultaneously with each other. I can do it.

Note that this invention is not limited to the above-described embodiments.

In the above explanation, in order to simplify the explanation, an example was explained in which each electrode block 19 includes the same number of light emitting elements, but the present invention is not necessarily limited to this. Even if the number of light emitting elements they have is different in part or all, the same effect as in the example can be obtained by driving the block having the largest number of light emitting elements as the center, for example, as in the example. I can do it.

Further, the drive circuit shown in FIG. 3 is merely an example, and it is clear that various modifications can be made within the scope of the invention.

Furthermore, the present invention can be applied to a DC type PDP or an AC type PDP.
It is clear that the present invention can be applied to optical heads using either of the above.

(Effects of the Invention) As is clear from the above description, according to the method for driving a plasma discharge optical head of the present invention, when focusing on adjacent electrode blocks, the time period during which one of the electrode blocks is driven is During this period, the other electrode block will not be driven.

Therefore, as explained using FIG. 7, erroneous light emission caused by losstalk does not occur at all.

This makes it possible to cope with higher speed and higher resolution printers.

[Brief explanation of the drawing]

FIG. 1 is a plan view of essential parts showing the configuration of a plasma discharge optical head suitable for carrying out the method for driving a plasma discharge optical head of the present invention, and FIG. FIG. 3 is a block diagram schematically showing a drive circuit suitable for use in the plasma discharge optical head driving method of the present invention; FIG. , FIG. 4 is a timing diagram showing the operation of the circuit section on the common electrode side of the drive circuit shown in FIG. 3, and FIG. 5 is a timing diagram showing the operation of the circuit section on the individual electrode side of the drive circuit shown in FIG. 3. FIG. 6 is a timing diagram showing drive signals for emitting and extinguishing light of plasma light emitting devices according to the conventional art and the present invention, and FIGS. 7 and 8 are diagrams for explaining the present invention. 11J3...Substrate, 15...Individual electrode 17.
...Common electrode, 18...Individual light emitting element 19
(19a to 19e) - Electrode blocks 31a, 31b -
? ML, CH wiring 51...First individual electrode drive driver 53...Second individual electrode drive driver 55...Counter decoder 61...First common electrode drive driver 63...Second common Electrode driving driver 65.67...Shift register. Patent applicant: Oki Electric Industry Co., Ltd. Δ Higashi N N University
1 1 -1111cho ni no 1 intoxication Ilr failure 4”1.

Claims (1)

[Claims] (1) When driving a plasma discharge optical head that includes a plurality of electrode blocks in which a plurality of electrode blocks are assigned to each of a plurality of common electrodes arranged in a line, even-numbered and odd-numbered electrode blocks are used. 1. A method for driving a plasma discharge optical head, characterized in that the even-numbered electrode blocks are driven at the same time and the odd-numbered electrode blocks are driven at the same time.