JPH03216355A - Electrostatic recording method and device therefor - Google Patents

Abstract

PURPOSE:To prevent the misregistration of a recording image by a method wherein the rotating speed or position of a latent image holder is detected to be corrected, and in accordance with the corrected rotating speed or position of the latent image holder, an electrostatic recording head drive timing is controlled. CONSTITUTION:Printing data inputted to an image buffer 28 is outputted to a drive circuit 30 in accordance with a timing signal generated by a timing generator 29. An electrostatic latent image is recorded by driving an electrostatic recording head 2 by the drive circuit 30. At this time, the generation of the timing signal by the timing generator 29 is determined based on a pulse signal 40 outputted from an encoder 22, but it is not determined by the pulse signal 40 per se but based on a pulse cycle corrected by a pulse cycle correction circuit 31.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an electrostatic recording method and device used in printers, facsimiles, etc. The present invention relates to an electrostatic recording method and apparatus for recording images.

[Conventional technology]

Conventionally, as this type of electrostatic recording device, there are the following types. That is, as shown in FIG. 14, the electrostatic recording head 101 is placed opposite the surface of the dielectric drum 100.
A desired electrostatic latent image is formed on the surface of the dielectric drum 100 by the electrostatic recording head 101.

As shown in FIGS. 15 and 16, the electrostatic recording head 101 has a plurality of drive electrodes 1 on the surface of an insulating substrate 102.
03, 103, . ...and 104, 104...
・Construct a matrix by. The control electrodes 104, 104, . . . have drive electrodes 103, 103, etc.
An opening 1 as a discharge generation area is located at a position intersecting with...
05, 105, etc. are formed. These control electrodes 104
, 104... are formed in the openings 105, 105...
・ is the drive electrode 103, 103 ・ that constitutes the matrix.
... and the control electrodes 104, 104..., these openings 105, 105...
... itself also forms a matrix, as shown in FIG.

Further, on the lower surface of the control electrodes 104, 104...
As shown in FIGS. 17 and 18, a screen electrode 107 is provided through an insulating layer 106, and control electrodes 104, 104 are provided on these insulating layer 106 and screen electrode 107, as shown in FIG. The openings 108 are located at positions corresponding to the openings 105, 105...
, 108... and openings 109, 10 for ion extraction
Form 9...

The electrostatic recording head 101 applies an alternating electric field to the drive electrode 103 and a DC voltage to the screen electrode 107, as shown in FIG. Also,
A high voltage corresponding to the image signal is applied in a pulsed manner to the control electrodes 104, 104, . . . .

By doing this, the drive electrodes 103, 103... and the control electrodes 104, 104, to which a voltage is selectively applied,
As shown in FIG. 19, a creeping corona discharge is generated in the openings ]05, ]05..., and the ion flow generated by this creeping corona discharge is transferred to the control electrode 1.
04, 104... and the screen electrode 107, the ions are accelerated or absorbed by the electric field, and the release of the ions is controlled to form an electrostatic latent image of the ions on the dielectric drum 100 according to the image signal. It is designed to be formed by

At that time, the control electrodes 104, 104, which generate ions
Since the openings 105, 105, . . . constitute a matrix, these openings 105, 105, .
Drive electrodes 103, 103... and control electrodes 104, 104 so that a desired electrostatic latent image can be formed on dielectric drum 100 by controlling the release of ions from
... are driven in synchronization with the rotation of the dielectric drum 100 as follows.

That is, as shown in FIG. 14, an encoder 110 is attached to the rotation shaft of the dielectric drum 100, and the rotation speed or position of the dielectric drum is detected by the encoder 110. Then, while the pulses from the encoder 110 are output for one period T, as shown in FIG.
A control electrode 104 that sequentially drives a plurality of drive electrodes 103, 103, . A pulse voltage is applied to 104... By doing this, the drive electrodes 103, 103... and the control electrodes 104, 104 to which a voltage is applied
In the openings 105, 105... between...
A creeping corona discharge is generated, and the ion flow generated by the creeping corona discharge is accelerated or absorbed by an electric field formed between the control electrodes 104, 104, . . . and the screen electrode 107, thereby controlling the release of ions. Then, an electrostatic latent image of ions is formed on the dielectric drum 100 according to the image signal.

The electrostatic latent image formed on the dielectric drum 100 in this way is developed into a toner image by a developing device 111, as shown in FIG.
An image is recorded on the recording paper +13 by simultaneously transferring and fixing the image by pressure onto the recording paper 113 that is supplied to the nip between the recording paper +112 and the pressure roller 112 that presses against the recording paper +13. In the figure, 114 is a cleaner that removes the toner remaining on the surface of the dielectric drum 100 after the toner image has been transferred as described above, and 115 is a cleaner that removes the toner remaining on the surface of the dielectric drum 100 after the toner image has been transferred.
Each figure shows a static eliminator that erases the charge remaining on the surface of the

[Invention or problem to be solved]

However, the above conventional technology has the following problems. That is, the drive electrodes 103, 103.
... and the head drive signals applied to the control electrodes 104, 104, etc., as shown in FIG.
ll and a control electrode signal 112, and an opening 109 to which both electrode signals 111 and 112 are applied simultaneously;
Ions are emitted in a dot shape only from 109, and an electrostatic latent image is formed.

In FIG. 21, when a pulse voltage is simultaneously applied to the first drive electrode 103 and the first control electrode 104, a dot di is printed.

As shown in FIG. 20, during one period T of the pulse output from the encoder 11O, the drive electrode signal 1
1-1 are sequentially driven from the first to the fifth with a predetermined pulse width Tw and pulse interval Td, and the control electrode 104
, 104... are driven in synchronization with the drive electrode signal 111, and the dots di, d2, d3, d4, d5 are sequentially printed. In addition, the above dots di, d2, d3, d4, d5
Next to these, there are also dots d1°, d2', d3.
', d4' and d5' will be printed.

Next, when the next pulse is output from the encoder 110 as shown in FIG. 20 as the dielectric drum 100 rotates, the first drive electrode 103 is sequentially driven in the same manner as described above. At this time, since the dielectric drum 100 is rotating, the dot di previously recorded by the electrostatic recording head 101 is placed at an adjacent position along the rotation direction A of the dielectric drum 100 as shown in FIG. , dot d6 is printed. Thereafter, each time a pulse is output from the encoder 110 for one cycle as the dielectric drum 1 rotates,
dot dll. dl6, d2]. ,d26,d31,d
36 and d41 are sequentially printed in a matrix along the rotational direction A of the dielectric drum 100 to record a desired image.

As a result, next to d5'' printed fifth by the first pulse output from encoder 110, 41
The dots d41 printed next are printed side by side.

By the way, when a pulse is output from the encoder 110 once, the positions of print dots di, d2, . The pitch is basically determined by the pitch of the drive electrodes 103, 103, . dot di. The positions of d6, dll, . . . are determined by the pitch of the pulses output from the encoder 110.

Therefore, due to manufacturing errors in the electrostatic recording head 101, there may be variations in the spacing between the drive electrodes 103, 103..., an error in the number of pulses output from the encoder 110, or an error in the diameter of the dielectric drum 100. If there is an error, the electrostatic recording head 10 as shown in FIG.
The pitch d of dots printed by one adjacent drive electrode 103, 103 and the pitch P of dots printed sequentially according to the pulses output from the encoder 110 are multiplied by a predetermined integer n (in the illustrated example, n=2). The results will no longer match each other. Therefore, for example, dot d4l, which should be printed next to dot d5', is printed next to dot d5'.
are not printed next to each other, but are printed shifted in the rotational direction A of the dielectric drum 100. As a result, as shown in Figure 22, when recording the kanji character ``品'', for example, the horizontal lines of the character are regularly deformed into a sawtooth shape when printed, which significantly reduces the image quality. there were.

If we consider this problem numerically, we will find the following.

That is, 1 of the pulses output from the encoder 110
If the cycle is T and the recording time per dot by the electrostatic recording head 101 is TD (-Tw+Td), one cycle T of pulses output from the encoder 110 and the recording time TD per dot are as follows. It can be expressed as

T=P/v (1)TD=
T/'N=P/Nv (2) Here, the 8th
As shown in the figure, P is the pitch of dots printed adjacently on the dielectric drum 100 along the rotation direction A;
is the circumferential speed of the dielectric drum l00, N is the drive electrode 103, 1
03... is the number.

In order to record printed dots in the order of di, d2, d3, ... d5, the drive electrodes 103, 103, ... are sequentially driven with a predetermined pulse width Tw and pulse interval Td, during which the dielectric drum 100 rotates. Therefore, dielectric drum 1
The interval d between the dots d1 and d2 recorded on the electrostatic recording head 101 is set to an integer n (in the illustrated example, n=2) times the dot pitch P. The geometric interval d° between the drive electrodes l03, 103...
Since it is equal to the sum of the distance that the dielectric drum 100 moves during the time TD, this interval d is calculated as follows, considering equation (2): d=nP=d' +vTD = d' +P/N (
3). Therefore, the pitch P is determined by transforming this equation (3) as follows: P=d'/(n-1/N) (4).

On the other hand, the pitch P° determined by the pulses output from the encoder 110 is calculated as follows: where the diameter of the dielectric drum 100 is l1 and the number of pulses generated per one rotation of the encoder 110 is NE. −． P'=π12/NE
It is given by (5).

Here, if the pitch P of the dots printed adjacently on the dielectric tram 100 along the rotation direction A matches the pitch P' determined by the pulse output from the encoder 110, the printed image There will be no discrepancy.

Now, the drive electrodes 103 and 10 on the electrostatic recording head 101
3... on the dielectric drum 100 is set to 0.
．． 2mm, n is 2, and the number N of drive electrodes 103, 103... is 5.
10 dots I-/ on 0mm dielectric drum 100
Let us consider the case of printing mm. At that time, the number of pulses NE that the encoder 110 used outputs per rotation
is 6000, the pitch P given by equation (4) is P=0.2/ (2-1/5)''=.0.11
It becomes 1.

On the other hand, the pitch P′ given by (5)
becomes P'=200π/6000#0.105.

Therefore, there is a difference of 0.006 mm between the pitches P and P', and a step difference of 0.048 mm, which is eight times that difference, occurs between the pitches d41 and d5'.

This difference in level occurs because the pitch P of dots printed adjacently on the dielectric drum 100 along the rotation direction A does not match the pitch P' determined by the pulses output from the encoder 110.

Therefore, the above-mentioned step may be caused by variations in the distance d° between the drive electrodes 103, 103... of the electrostatic recording head 101, an error in the number of pulses NB output from the encoder 110, or an error in the diameter of the dielectric drum 100. When becomes larger, it expands further.

Therefore, as described above, when an image is recorded, the horizontal lines of the characters are regularly deformed into sawtooth shapes and printed, resulting in a problem that the image quality is significantly degraded.

[Means to solve the problem]

Therefore, the present invention was made to solve the above-mentioned problems of the prior art, and its purpose is to improve the pitch of the drive electrodes of the electrostatic recording head, the pitch of the pulses output from the encoder, etc. An object of the present invention is to provide an electrostatic recording method and an apparatus thereof that can record high-quality images without causing deviations in recorded images even when differences exist.

That is, the present invention forms an electrostatic latent image on a rotating latent image carrier using an electrostatic recording head that records an electrostatic latent image by emitting ions in a matrix according to an image signal. In an electrostatic recording method in which an image is recorded by developing and visualizing an electrostatic latent image, the rotational speed or position of the latent image carrier is detected, and the rotational speed or position of the latent image carrier is detected. The rotational speed or position is corrected, and the drive timing of the electrostatic recording head is controlled in accordance with the corrected rotational speed or position of the latent image carrier.

Further, the electrostatic recording device according to the present invention includes an electrostatic recording head that records an electrostatic latent image by emitting ions in a matrix according to an image signal, and an electrostatic recording head that records an electrostatic latent image by emitting ions in a matrix according to an image signal; a rotatable latent image carrier carrying a latent image; a pulse generating means for generating output control pulses for the electrostatic recording head at a predetermined period as the latent image carrier rotates; and the pulse generating means. and a pulse period correction means for correcting the period of the pulse output from the electrostatic recording head, and is configured to control the output of the electrostatic recording head using the correction pulse corrected by the pulse period correction means.

The pulse period correction means may include, for example, a period measurement means for measuring a pulse period, a correction factor setting means for setting a correction factor for the period, and a multiplication means for multiplying the pulse period by the correction factor. things are used.

[Effect]

In the electrostatic recording method according to the present invention, the rotational speed or position of the latent image carrier is detected, the detected rotational speed or position of the latent image carrier is corrected, and the latent image carrier is Since the drive timing of the electrostatic recording head is controlled according to the rotational speed or position, there is a difference between the pitch of the drive electrode of the electrostatic recording head and the detected rotational speed or position of the latent image carrier. Even if there is a difference in the rotational speed or position of the latent image carrier, the detected rotational speed or position of the latent image carrier is corrected, and the drive timing of the electrostatic recording head is controlled according to the corrected rotational speed or position of the latent image carrier. Therefore, it is possible to drive the electrostatic recording head in accordance with the pitch of the driving electrodes of the electrostatic recording head, and therefore it is possible to prevent a positional shift from occurring in a recorded image.

Further, the electrostatic recording device according to the present invention includes an electrostatic recording head that records an electrostatic latent image by emitting ions in a matrix according to an image signal, and an electrostatic recording head that records an electrostatic latent image by emitting ions in a matrix according to an image signal; a rotatable latent image carrier carrying an electrostatic latent image; a pulse generating means for generating output control pulses for the electrostatic recording head at a predetermined period as the latent image carrier rotates; and the pulse generator. and a pulse period correction means for correcting the period of the pulse outputted from the means, and is configured to control the output of the electrostatic recording head using the correction pulse corrected by the pulse period correction means. Even if there is a difference between the pitch of the driving electrodes of the electrostatic recording head and the detected rotational speed of the latent image carrier, the output of the electrostatic recording head is adjusted by the correction pulse corrected by the pulse period correction means. Since the control can be performed, the pitch of the driving electrodes of the electrostatic recording head and the pitch of the pulses output from the pulse generating means can be matched with each other, thereby preventing positional deviation from occurring in the recorded image. I can do it.

〔Example〕

The present invention will be explained below based on illustrated embodiments.

FIG. 2 shows an embodiment of an electrostatic recording device according to the present invention. In the figure, the symbol (■) indicates a dielectric drum as a latent image carrier, and this dielectric drum 1 is rotatable in the direction of the arrow by a drive means (not shown). An electrostatic recording head 2 is arranged above the dielectric drum 1 so as to face it at a predetermined distance.

As shown in FIG. 3, the electrostatic recording head 2 includes a first insulating substrate 3 having a rectangular planar shape. As shown in FIG. 4, on the surface of the first insulating substrate 3, a plurality of linear drive electrodes 4, 4, . is the drive electrode 4,
A plurality of control electrodes 5, 5... so as to intersect with 4...
are provided, and both electrodes 4, 4... and 5, 5...
・The matrix is formed by As shown in FIGS. 3 and 4, the control electrodes 5, 5, . . . have circular openings at positions intersecting with the drive electrodes 4, 4, . Sections 6, 6... are provided. These openings 6, 6..., because the drive electrodes 4, 4... and control electrodes 5, 5... constitute a matrix, these electrodes 4, 4... and 5...
, 5, . . . also form a matrix, as shown in FIG. These first insulating substrates 3, drive electrodes 4, 4...
. and the control electrodes 5, 5, . . . constitute an ion generating section 7, as shown in FIG.

As shown in FIG. 5, a screen electrode 9 is provided on the lower surface of the control electrodes 5, 5, . . As shown in FIG. 6, this spacer layer 8 is formed into a planar rectangular shape having a length almost equal to that of the first insulating substrate 3 and a slightly narrow width, and is attached to the first insulating substrate 3 by bonding or other means. It is fixed to 3. As shown in FIG. 5, this spacer layer 8 has openings 6, 6, .
Openings 10, 10, . . ., which are larger than the openings 6, 6, . . ., are provided at positions corresponding to the openings 6, 6, . Also,
The screen electrode 9 is provided with openings 11, 1l, . . . as ion extraction regions at positions corresponding to the openings 6, 6, . . . of the control electrodes 5, 5, .

In FIG. 4, reference numeral 12 indicates a head substrate that covers the surfaces of the drive electrodes 4, 4, . . . .

Furthermore, as will be described later, a pulsed drive signal is applied to the drive electrodes 4 and control electrodes 5, and the drive electrodes 4, 4, etc. to which a voltage is selectively applied Openings 6, 6... between the control electrodes 5, 5...
As shown in FIG. The ion current S is controlled and released from the openings 11, 11, . It has become.

The head drive signal applied to the drive electrode 4 and control electrode 5 consists of a drive electrode signal and a control electrode signal, as will be described later, and the openings 1l, 1l, . . . to which both electrode signals are applied simultaneously・Ions are emitted in dots only from the inside. In FIG. 8, a dot d1 is printed when a pulse voltage is simultaneously applied to the first drive electrode 4 and the first control electrode. Then, as will be described later, while the encoder outputs one pulse, the drive electrode signals are changed from the first to the Nth at a predetermined interval Td.
The dots d1, d2, d3, . d4, d5
will be printed sequentially. And dielectric drum 1
As the dielectric drum l rotates, the next pulse from the encoder causes the first drive electrode to be sequentially driven, and as the dielectric drum l rotates, a dot d6 is printed at a position adjacent to the dot di. Thereafter, for each pulse output from the encoder as the dielectric drum l rotates, dll, dl6, d
21. They are printed sequentially as d26, d31, d36, and d41. As a result, next to d5' printed fifth by the first pulse from the encoder, d
The 41st dots will be printed side by side.

By driving the drive electrodes 4 and control electrodes 5 constituting the matrix as described above, the letter E, for example, is printed as shown in FIG. 9.

In this way, the dielectric drum 1 is
As shown in Figure 2, the electrostatic latent image formed on the surface of
The toner image is visualized by a developing device l6 disposed on the side of the dielectric drum l, and becomes a toner image. The toner image formed on the surface of the dielectric drum 1 is transferred to a recording paper l7 that is supplied from a paper feeder (not shown) in synchronization with the rotation of the dielectric drum 1.
The image is transferred and fixed at the same time.

Transfer and fixation of this toner image is performed as follows.

That is, the pressure roller 18 is placed on the surface of the dielectric drum 1.
The recording paper 13 is brought into contact with a predetermined pressure (for example, 150 to 2001 (g/cd)), and is formed on the dielectric drum 1 by supplying the recording paper 13 to the nip between the dielectric drum l and the pressure roller l8. The printed toner image is transferred to recording paper l7.
The image is transferred and fixed at the same time using pressure.

After the toner image transfer and fixing process has been completed as described above, the dielectric drum 1 is cleaned by a cleaner 19 to remove residual toner and the like, and a static eliminator 20 to erase charges remaining on the surface.

Incidentally, this embodiment is configured to include a pulse generating means for generating output control pulses for the electrostatic recording head at predetermined intervals as the latent image carrier rotates. That is, as shown in FIG. 10, the dielectric drum 1 has an encoder 22 attached to its rotating shaft 21 as a pulse generating means, and the rotation speed of the dielectric tram 1 is detected by the encoder 22. It has become so.

As shown in FIG. 11, the encoder 22 is fixed to the rotating shaft 21 of the dielectric drum 1, and has slits 23a, 23a...
A rotating disk 23 with a engraved on it, a transmission type optical sensor 24 arranged on the outer periphery of the rotating disk 23 and optically detecting passage through the slits 23a, 23a, . . . The output is amplified and the slits 23a, 23
It is composed of an amplifier 25 that outputs a pulse signal synchronized with the passage of a.

The encoder 22 detects the rotation of the rotating disk 23 fixed to the rotating shaft 2l of the dielectric drum 1 with the optical sensor 24, and outputs a pulse signal synchronized with the rotation of the rotating disk 23 from the amplifier 25. By doing so, the rotational speed of the dielectric drum 1 is detected, and pulses for controlling the output of the electrostatic recording head 1 are generated at a predetermined period.

The block diagram in FIG. 2 shows the signal processing section of the electrostatic recording apparatus according to this embodiment. In the figure, 26 is an image memory that stores print data sent from a host computer (not shown), and 27 is an image memory 2.
28 is a data assembler for rearranging the print data stored in 6 according to the matrix of drive electrodes 4, 4... and control electrodes 5, 5... of electrostatic recording head 2; 28 is from data assembler 27; an image buffer 29 that temporarily holds print data sent to the electrostatic recording head 2;
30 is a timing generator that generates a timing signal for driving the electrostatic recording head 2 based on the print data held in the image buffer 28, and 30 is a control electrode 5 of the electrostatic recording head 2. , 5, etc., a drive circuit that applies a predetermined voltage to drive the encoder 2, and 3l is the encoder 2.
2 shows a pulse period correction circuit that corrects the period of the pulse signal output from the circuit 2.

FIG. 1 further shows the configuration of the pulse period correction circuit in detail. In the figure, 32 is an encoder period measuring circuit that measures the period T of the pulse signal output from the encoder 22 based on the reference clock, 33 is a latch circuit that latches the measured value from the encoder period measuring circuit 32, and 34 is the encoder period. An increase/decrease value setting circuit 35 sets a correction value to be added to the pulse period measured by the measurement circuit 32, and 35 multiplies the pulse period latched by the latch circuit 33 based on the correction value set in the increase/decrease value setting circuit 34. A multiplication circuit; 36 is a selector that switches whether to add or subtract the correction value calculated by the multiplication circuit 35 to the pulse period T measured by the encoder period measurement circuit 32; 37 is a selector 36 that adds or subtracts the correction value; 38 is the latch circuit 3.
3 is an addition/subtraction circuit that adds or subtracts the correction value calculated by the multiplication circuit 35 to the measured value of the period T from the encoder fixed at 3; and 39 is a latch circuit that latches the value calculated by the addition/subtraction circuit 38. In the above configuration, in the electrostatic recording apparatus according to this embodiment, images are electrostatically recorded in the following manner. That is, as shown in FIG. 2, print data sent from a host computer (not shown) and written in the image memory 26 is rearranged by the data assembler 27 in accordance with the matrix of the electrostatic recording head 2, and is stored in the image buffer 28. is input. The print data input to the image buffer 28 is output to a drive circuit 30 in accordance with a timing signal generated by a timing generator 29, and the drive circuit 30 drives the electrostatic recording head 2. A recording of the electrostatic latent image is performed.

At this time, the generation of the timing signal by the timing generator 29 is determined based on the pulse signal 40 output from the encoder 22, but is not determined by the pulse signal 40 itself output from the encoder 22, It is determined based on the pulse period corrected by the pulse period correction circuit 31 as follows.

That is, the pulse period correction circuit 3l, as shown in FIG.
The period T of 0 is measured by the encoder period measuring circuit 32 based on the reference clock. The periodic signal of the pulse signal 40 output from the encoder 22 measured by the pulse period measuring circuit 32 is transmitted to the latch circuit 3.
3 and sent to the multiplication circuit 35, where the multiplication operation is performed based on the value preset in the increase/decrease value setting circuit 34. This increase/decrease value setting circuit 34 includes drive electrodes 4, 4, . . . of the electrostatic recording head 2.
The increase/decrease value is set so that the pitch of * and the pitch of the pulse output from the encoder 22 are equal. next,
The correction value calculated by the multiplication circuit 35 is sent to the selector 36, and the selector 36 switches whether the correction value is set in the set circuit 37 and added or subtracted as expected.

Next, the correction value is added to or subtracted from the value latched by the latch circuit 33 by the addition/subtraction circuit 35.

The added and subtracted values are then output to the timing generator 29 via the latch circuit 39.

Then, in this timing generator 29, based on the pulse width Tw and pulse interval Td set in advance in the timing generator 29, based on the corrected pulse signal 4l sent from the pulse period correction circuit 3I, A timing signal for driving the electrostatic recording head 2 is generated in accordance with print data in the following manner.

That is, as shown in FIG. 12, the drive signal for the electrostatic recording head 2 consists of a drive electrode signal 38 and a control electrode signal 39, and the drive electrode signal 38 and the control electrode signal 39 are turned on at the same time. The latent image is printed when The drive electrode signal 38 is synchronized with the rise of the pulse T' corrected by the pulse period correction circuit 31.
The first drive electrode 4l, the second drive electrode 42, and the third drive electrode 43 are sequentially turned on. At that time, the drive electrode signal 38 is sequentially turned on based on a preset pulse width Tw, and the encoder 22
The first drive electrode signal 381 is turned on for the pulse width Tw in synchronization with the rise of the pulse with a period T° that is output from the control circuit 31 and corrected by the pulse period correction circuit 3l. When the interval Td between the pulse signals has elapsed, the second drive electrode signal 382 is turned on by the pulse width Tw.

Thereafter, the same process is repeated to print one line of latent image. At this time, a control electrode signal 39 is applied in a pulsed manner to the control electrode 5 in accordance with the print data and in synchronization with the drive electrode signal 38 described above.

By the way, the corrected pulse output signal 4l outputted from the pulse period correction circuit 31 is transmitted to the increase/decrease value setting circuit 34.
The period T of the pulses output from the encoder 22 is corrected based on the value set in .

Therefore, even if there are variations in the spacing between the drive electrodes 4, 4, etc. of the electrostatic recording head 2, an error in the number of pulses output from the encoder 22, or an error in the diameter of the dielectric drum l, the electrostatic The pitch d of the dots printed by the adjacent drive electrodes 4 and 43 of the recording head 2 and the pitch P of the dots sequentially printed according to the pulses output from the encoder 22 multiplied by a predetermined integer n are made to match each other. I can do it.

That is, the adjacent drive electrodes 4, 4 of the electrostatic recording head 2
As shown in FIG. 8, the pitch P obtained by dividing the pitch d of dots printed by 1/n is given by the above-mentioned equation (4).

P=d'/(n- 1/N) (4)
This value P is the drive electrodes 4, 4, . . . of the electrostatic recording head 2.
the geometric interval d°, the number n1 of dots printed at this dot interval d°, and the drive electrode 4 of the electrostatic recording head 2,
It is uniformly determined by the number N of 4....

On the other hand, the period T of the pulse signal 40 output from the encoder 22 is corrected by the pulse period correction circuit 3l so as to match the pitch of the drive electrodes 4, 4, . . . of the electrostatic recording head 2.

That is, the adjacent drive electrodes 4, 4 of the electrostatic recording head 2
The pitch d of dots printed by is 1/n L
With respect to the pitch P, the drive electrode 4 on the electrostatic recording head 2
, 4... on the dielectric drum l is set to 0.
2mm, n is 2, number N of drive electrodes l03, 103...
Using an electrostatic recording head lOl with a diameter of 200 mm
Consider the case where printing is performed at 10 dots/mm on a dielectric drum 100 of mm. At that time, the number of pulses NB output per rotation by the encoder IIO used is 600.
When set to 0, the bit P given by equation (4) is
P=0.2/(2-1/5)''.0.111.

On the other hand, the value before correction of pitch P' given by equation (5) above is P'=200π/6000#0.105, and there is a difference of 0.006 mm between both pitches P and P'. exists.

Therefore, the pulse period correction circuit 31 corrects the period T of the pulse from the encoder 22 by increasing it by 5.71%.

By doing this, the corrected pitch P of the pulses output from the encoder 22 is P゜=0, l05+0.105x0.0571#0.1
It becomes 1099.55.

As a result, the difference between the pitch P and the corrected pitch P' is 0,111-0.109955=0.00000
It becomes 45mm, and the positional deviation of the dots before correction is 0.
The difference is 0.048 mm (48 μm), or 1/2 dots, but after correction it is 0.000036 mm (0.036
(μm) That is, the deviation is only about 173,000 dots, which is a value that can be ignored in practice.

Then, as shown in FIG. 13(a), the pulse 41 corrected by the pulse cycle correction circuit 3l sends a signal to the timing generator 29 to control the driving of the electrostatic recording head 2. It has become. Same figure (b)
shows the case where negative correction is performed.

By the way, in this method, the signal 4 from the encoder 22
Since a new pulse signal 41 is generated by correcting 0 by the pulse period correction circuit 31, there is a possibility that the pulse signal 40 from the encoder 22 and the corrected pulse signal 4l may deviate by many periods. Therefore, in this embodiment, this problem is prevented by using the period measured while outputting the correction signal 4l for the next pulse.

To further explain this, as shown in FIG. 13(a),
When outputting the correction pulse Tl', the period T of the pulse 40
I is measured and corrected to create a pulse signal 41 with a period T2'. Then, pulse signal 4 with period T2'
1, the period T2 of the pulse 40 is measured, and when the pulse signal 41 with the period T3' is output, the period T3 of the pulse 40 is skipped by one, and the period T4 of the pulse 40 is measured. Therefore, the pulse signal 4 from the encoder 22
The period difference between 0 and the corrected pulse signal 41 is 1 to
Since it is within 2 pulses, the problem that the pulse signal 40 from the encoder 22 and the corrected pulse signal 4l deviate by many cycles does not occur.

FIG. 13(b) shows the case where the correction is made to the negative side. In this case, the period of the corrected pulse signal 41 becomes shorter, so the period T3 of the pulse 40 is measured twice. The timing is being adjusted.

This timing control is performed, for example, as follows. That is, the operation of measuring the encoder cycle and writing a new cycle to the latch 39 is carried out each time, and the printing part circuit takes out the new cycle stored in the latch when printing is finished.

By doing this, as shown in FIG. 13(a), when printing extends for a long time, since a new cycle is always written in the latch, printing is performed at the latest cycle. That is, if printing is in progress, the old cycle is erased from the latch, the new cycle is latched, and this is repeated in another cycle. Moreover, as shown in FIG. 13(b),
On the other hand, when printing becomes shorter, the printing side repeatedly reads and prints old data from the latch until a new cycle is latched.

In this case, if new data is sent into the latch at the same time that the latch data is being read, it will be disrupted, and the latch will be disabled so that no data can be written to it.

As described above, the adjacent drive electrodes 4 of the electrostatic recording head 2
, 4, and the pitch P' determined by the pulses output from the encoder 22. By correcting the period of the pulse, both pitches P and P' can be made to match each other, and a high-quality image can be recorded without positional deviation of printed dots.

As described above, the electrostatic recording apparatus according to this embodiment includes the electrostatic recording head 2 that records an electrostatic latent image by emitting ions in a matrix according to an image signal, and the electrostatic recording head 2. a rotatable dielectric drum 1 that carries an electrostatic latent image formed by a rotatable dielectric drum 1; and an encoder 22 that generates pulses for controlling the output of the electrostatic recording head at a predetermined period as the dielectric drum l rotates. , a pulse period correction circuit 3l that corrects the period T of the pulse 40 output from the encoder 22, and the output of the electrostatic recording head 2 is controlled by the correction pulse 4l corrected by the pulse period correction circuit 3. Since it is configured to do
Even if there is a difference between the pitch P of the drive electrodes 4, 4, . . . of the electrostatic recording head 2 and the detected rotational speed of the dielectric drum 1, the correction made by the pulse period correction circuit 31 The electrostatic recording head 2 is activated by the pulse 4l.
Since the output of the electrostatic recording head 2 can be controlled,
Since the pitch P of the drive electrodes 4, 4, . High quality image recording can be performed.

〔Effect of the invention〕

This invention has the above-described structure and operation, and even if there is a difference between the pitch of the drive electrodes of the electrostatic recording head and the pitch of the pulses output from the encoder, no deviation occurs in the recorded image. , it is possible to provide an electrostatic recording method and apparatus capable of recording high-quality images.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the main parts of an electrostatic recording device according to the present invention, FIG. 2 is a block diagram showing an electrostatic recording device to which the electrostatic recording device according to the present invention can be applied, and FIG. Figure 4 is a plan view and a cross-sectional view showing the ion generation section of the electrostatic recording head;
5 and 6 are a cross-sectional view and a plan view showing the electrostatic recording head, FIG. 7 is a cross-sectional view showing the operation of the electrostatic recording head, and FIGS. 8 and 9 are also the recording heads of the electrostatic recording head. FIG. 10 is a perspective view showing the end of the dielectric drum, FIG. 11 is a configuration diagram showing the encoder, and FIG. 12 is an explanatory diagram showing the operation.
The figure is a timing chart showing the printing operation, and Fig. 13 (a)
), (b) are timing cheats showing the operation of this embodiment, FIG. 14 is a configuration diagram showing a conventional electrostatic recording device, and FIG. 15 is a timing cheat showing the operation of this embodiment.
16 and 16 are a plan view and a sectional view showing the ion generation section of the electrostatic recording head, FIGS. 17 and 18 are a plan view and a sectional view showing the electrostatic recording head, and FIG. 19 is a plan view and a sectional view showing the electrostatic recording head. 20 and 21 are timing charts and explanatory diagrams showing the recording operation of the electrostatic recording head, and FIG. 22 is an explanatory diagram showing a recorded image. [Explanation of symbols] ■...Dielectric drum 2...Electrostatic recording head 4...Drive electrode 5...Control electrode 11...Aperture 22...Encoder 31...Pulse period correction Circuit 32... Pulse period measuring circuit 35... Multiplier circuit Patent Applicant: Fuji Xerox Co., Ltd. Representative: Patent attorney Tomohiro Nakamura (external name) 6 Figure 4 12 Figure 6 Figure 7 Figure 8 Fig./ Fig. 9 Noic No. 2 ( No. 3) Fig. 16 Fig. 17 Fig. 18 Fig. 21

Claims (3)

[Claims] (1) An electrostatic recording head that records an electrostatic latent image by emitting ions in a matrix according to an image signal forms an electrostatic latent image on a rotating latent image carrier. In an electrostatic recording method in which an image is recorded by developing and visualizing the image, the rotation speed of the latent image carrier is detected and the detected rotation speed of the latent image carrier is corrected. ,
An electrostatic recording method characterized by controlling the drive timing of an electrostatic recording head according to the corrected rotational speed of a latent image carrier. (2) An electrostatic recording head that records an electrostatic latent image by emitting ions in a matrix according to an image signal, and a rotatable latent image that carries the electrostatic latent image formed by the electrostatic recording head. an image carrier, a pulse generating means for generating output control pulses for the electrostatic recording head at a predetermined cycle as the latent image carrier rotates, and correcting the cycle of the pulses output from the pulse generating means. 1. An electrostatic recording apparatus, comprising: a pulse period correcting means, and controlling the output of the electrostatic recording head using a correction pulse corrected by the pulse period correcting means. (3) The pulse period correction means includes a period measurement means for measuring the period of the pulse, a correction factor setting means for setting a correction factor for the period, and a multiplication means for multiplying the pulse period by the correction factor. The electrostatic recording device according to claim 2, characterized in that: