JPH03216354A - Electrostatic recording method and device therefor - Google Patents

Abstract

PURPOSE:To perform an image recording with high image quality by a method wherein the rotating speed of a latent image holder is detected, and in accordance with the change of the rotating speed of the latent image holder, an electrostatic recording head drive timing is controlled. CONSTITUTION:The rotation of a rotating disk 23 fixed on a rotating shaft of a dielectric drum 1 is detected by an optical sensor 24, whereby a pulse signal in synchronism with the rotation of the rotating disk 23 is outputted from an amplifier 25. In this manner, an encoder 22 detects the rotating speed or position of the dielectric drum 1. The title device is provided with a timing generator 29 generating a timing signal for driving an electrostatic recording head 2 based on printing data held in an image buffer 28; a drive circuit 30 applying a predetermined voltage to drive electrodes 4, 4..., control electrodes 5, 5..., and the like of the electrostatic recording head 2 to drive them; and a control circuit 31 controlling the timing signal for driving the electrostatic recording head 2 based on the signal from the encoder 22.

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. 16, 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. 17 and 18, the electrostatic recording head 101 has a plurality of drive electrodes 1 on the surface of an insulating substrate 102.
03, 103, . ...and l04, 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... are formed. These control electrodes 10
4, 104... are formed in the openings 105, 105.
. . . are drive electrodes 103, 103 forming a matrix.
... and the control electrodes 104, 104..., these openings 105, 105...
. . . itself also forms a matrix, as shown in FIG. 17.

Further, on the lower surface of the control electrodes 104, 104...
As shown in FIGS. 19 and 20, 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 selectively 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. 21, a creeping corona discharge is generated in the openings 105, 105, .
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. 16, an encoder 110 is attached to the rotation shaft of the dielectric drum 100, and the rotation speed of the dielectric drum is detected by the encoder 110.

Then, the pulse from the encoder 110 has one period T
As shown in the figure, the plurality of driving electrodes 103, 103, . Control electrodes 104, 104 for recording latent images
Apply a pulse voltage to...

By doing this, the drive electrode 10 to which the voltage is applied
A creeping corona discharge is generated in the openings 105, 105... between the control electrodes 104, 104... and the control electrodes 104, 104... 104... and the screen electrode 107, and control the release of ions, forming an electrostatic latent image of ions on the dielectric drum 100 according to the image signal. do.

For example, when recording a linear image using the electrostatic recording head 101, as shown in FIG. 22, each drive electrode 103, 103, . . . While applying an alternating electric field to the control electrodes 104, 104, . . . in synchronization with the drive electrodes 103, 103, . That is, when the Nol drive electrode is driven first, the control electrode is turned on. Next, when the electrostatic latent image formed at that point comes under the No. 2 drive electrode as the dielectric drum 100 moves, the control electrode is turned on (the control electrode is turned on while the dielectric drum 100 is moving). ). By repeating this operation, a linear electrostatic latent image is formed on the dielectric drum 100 as the dielectric drum 100 moves, as shown in FIG.

The electrostatic latent image formed on the dielectric drum 100 in this way is developed by the developing device 111 into a toner image,
This toner image is transferred and fixed at the same time by pressure onto the recording paper 113, which is supplied to the nip between the dielectric drum 100 and the pressure roller 112 in pressure contact with the dielectric drum 100, thereby recording an image on the recording paper 113. do. In the figure, 11
Reference numeral 4 indicates a cleaner for removing toner remaining on the surface of the dielectric drum 100 after the toner image has been transferred and fixed as described above, and 115 indicates a static eliminator for erasing the charge remaining on the surface of the dielectric drum 100. ing.

[Problem to be solved by the invention]

However, the above conventional technology has the following problems. That is, in the case of the above electrostatic recording device,
The toner image formed on the surface of the dielectric drum 100 is transferred to the dielectric drum 100 and the pressure roller 11 that is pressed against the dielectric drum 100.
2, the image is transferred and fixed onto the recording paper 113. Therefore, the recording paper 113 is
), a dielectric drum 100 and a pressure roller 112
When entering the nip between the dielectric drum 100 and the pressure roller 112, the contact pressure between the dielectric drum 100 and the pressure roller 112 increases instantaneously, so that the rotational speed of the dielectric drum 100 instantaneously increases as shown in A in FIG. After the speed decreases, it repeats the vibration and returns to its original speed. After that, the recording paper 113 is shown in FIG. 24(B).
As shown in FIG. 25B, while passing through the nip between the dielectric drum 100 and the pressure roller 112, the rotational speed of the dielectric drum 100 is constantly maintained at a predetermined speed, as shown in FIG. 25B. Then, the recording paper 113 is shown in FIG. 24(C).
As shown in FIG. 2, even when the dielectric drum 100 and the pressure roller 112 come out of the nip, the contact pressure between the dielectric drum 100 and the pressure roller 112 momentarily decreases.
After the rotational speed of the dielectric drum 100 increases momentarily as shown in C in FIG. 25, it repeats vibrations and returns to its original speed.

In this way, the rotational speed of the dielectric drum 100 changes significantly when the recording paper 113 passes through the nip between the dielectric drum 100 and the pressure roller 112. Therefore, an encoder 1 is used to detect the rotational speed of the dielectric drum 100 and determine the drive timing of the electrostatic recording head 101.
As shown in FIG. 26, the period T of the 10 output pulses also changes as the recording paper 113 passes through the nip.

On the other hand, the drive signal for the electrostatic recording head 101 that is output based on the output signal from the encoder 110 is synchronized with the rise of the output pulse from the encoder 110, as shown in FIG. started and then preset constant pulse width TW and constant interval Td
is output in the form of a pulse signal so as to sequentially drive each drive electrode 103, 103, . . . .

As a result, when the rotation speed of the dielectric drum 100 decreases below a predetermined speed as the recording paper 113 passes through the nip, and the cycle of the output pulses of the encoder 110 becomes longer than the predetermined interval, the As shown in FIG. 26, the head drive signal is relatively shorter by Δt1. Furthermore, when the rotational speed of the dielectric drum 100 increases above a predetermined speed and the output signal of the encoder 110 becomes shorter than the predetermined interval, the head drive signal becomes relatively smaller as shown in FIG. It becomes longer by Δt2.

Therefore, the distance between the dot-like ions driven by the head drive signal and emitted from the openings 109, 109, . . . of the electrostatic recording head 101 is
As shown in FIG. 113, irregular disturbances occur as the image passes through the nip portion, resulting in a problem in that the image quality deteriorates.

[Means to solve the problem]

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to prevent the recording member from entering the nip between the latent image carrier and the pressure roller that presses against the latent image carrier. By controlling the drive timing of the electrostatic recording head, even if the rotational speed of the latent image carrier changes due to An object of the present invention is to provide an electrographic recording method and apparatus.

That is, the electrostatic recording method according to the present invention records 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 formed and an image is recorded by developing this electrostatic latent image, the rotational speed of the latent image carrier is detected, and the rotational speed of the latent image carrier is detected according to a change in the rotational speed of the latent image carrier. It is configured to control the drive timing of the electrostatic recording head.

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 pulses at a predetermined period as the latent image carrier rotates, and a pulse generating means based on the period of the pulse output from the pulse generating means. output control pulse generating means for generating output control pulses for the electrostatic recording head;
The apparatus is configured to include a control means for controlling the output of the output control pulse from the output control pulse generation means based on the period of the pulse output from the pulse generation means. The control means may, for example, measure the period of the pulse output from the pulse generation means and calculate 1/n (where n is a number characterizing the matrix of the electrostatic recording head) of the measured pulse period. Calculate 1
/ n period measuring means; and a subtracting means for subtracting the pulse width of a predetermined output control pulse from the 1 / n period measured by the 1 / n period measuring means to obtain the output interval of the output control pulse. What is available will be used.

In addition to the above-mentioned control means, the control means may include a period measuring means for measuring the period of the pulse outputted from the pulse generating means, and a period measuring means for measuring the period of the pulse outputted from the pulse generating means, and an output control pulse that is optimal for the period measured by the period measuring means. A device having storage means for storing the period may also be used.

Furthermore, the control means may control to output an output control pulse according to a predetermined pattern, for example, when the period of the pulse output from the pulse generation means is shorter than a predetermined value. used.

This 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. After the electrostatic latent image is developed and visualized, the developed image is placed on a recording member that is supplied to the nip between the latent image carrier and the pressure roller that is in pressure contact with the latent image carrier. In an electrostatic recording method that records an image by transferring and fixing it with pressure,
Although it is particularly effective, it is not limited to this, and it goes without saying that it can be applied to devices other than image recording devices by simultaneously transferring and fixing the developed image visualized on the latent image carrier. It is.

[Effect]

The electrostatic recording method according to the present invention is configured to detect the rotational speed of the latent image carrier and control the drive timing of the electrostatic recording head in accordance with a change in the rotational speed of the latent image carrier. Therefore, even if the rotational speed of the latent image carrier changes due to the recording member passing through the nip between the latent image carrier and the pressure roller that is in pressure contact with the latent image carrier, the latent image carrier Since the driving timing of the electrostatic recording head is controlled according to changes in the moving speed of the electrostatic recording head, the electrostatic recording head can always be driven in synchronization with the rotational speed 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 an electrostatic latent image; a pulse generating means for generating pulses at a predetermined period as the latent image carrier rotates; output control pulse generation means for generating output control pulses for the electrostatic recording head based on the output control pulse generation means; and output control output control output from the output control pulse generation means based on the period of the pulses output from the pulse generation means. and control means for controlling the output of the pulses, the rotational speed of the latent image carrier is detected by the pulse generation means, and the period of the pulses output from the pulse generation means is determined. In order for the control means to control the output of the output control pulse from the output control pulse generation means based on As a result, even if the rotational speed of the latent image carrier changes, the head drive signal will not become shorter by Δt1 or longer by Δt2, as shown in FIG. The electrostatic recording head can be driven in synchronization with the rotational speed of the body.

〔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, numeral 1 indicates a dielectric drum as a latent image carrier, and this dielectric drum 1 can be rotated 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 approximately the same length as the first insulating substrate 3 and a slightly narrower width, and is bonded 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,
Similarly, the screen electrode 9 is provided with openings 1l, 11, . . . as ion extraction regions at positions corresponding to the openings 6, 6, .

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...
Then, as shown in FIG. 7, a creeping corona discharge R is generated, and the ion flow S generated by this creeping corona discharge is caused by an electric field formed between the control electrodes 6, 6, . . . and the screen electrode 9. Accelerate and open the opening 1 of the screen electrode 9
The ion current S is controlled and emitted from i11, .

The head drive signal applied to the drive electrode 4 and the control electrode 5 consists of a drive electrode signal and a control electrode signal, as will be described later, and the openings 11, 1l, . . . to which both electrode signals are applied simultaneously.・Ions are emitted in dots only from the inside. In FIG. 8, when a pulse voltage is simultaneously applied to the first drive electrode 4 and the first control electrode, doso l-di is printed. As will be described later, while a pulse is output from the encoder once, the drive electrode signals are transmitted from the first to the nth (n is the number of drive electrodes 4: 5 in the illustrated example) at a predetermined interval Td. The control electrodes are driven sequentially, and the control electrodes are driven in synchronization with the respective timings, so that the dots d1, d2, d3, d4, . d
5 will be printed sequentially. Then, with the next pulse from the encoder as the dielectric drum 1 rotates,
The dielectric drum l is sequentially driven from the first drive electrode.
As the dot d6 rotates, the dot d6 is placed upstream of the dot d1.
is printed. Thereafter, for each pulse output from the encoder as the dielectric drum 1 rotates, dll, dl6
, d21, d26, d31, d36, d41. As a result, the d41st dot is printed side by side next to the 5th dot d5' printed by the first pulse from the encoder.

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

In this way, the electrostatic recording head 2 records the dielectric drum l.
As shown in Figure 2, the electrostatic latent image formed on the surface of
The toner image is visualized by a developing device 16 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 1B is placed on the surface of the dielectric drum l.
are in pressure contact with each other at a predetermined pressure (for example, 150 to 200 kg/cnf), and by supplying the recording paper l3 to the nip between the dielectric drum 1 and the pressure roller 18, the recording paper l3 is formed on the dielectric drum l. Transfer the toner image 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 has a cleaner 19 to remove toner remaining on the surface thereof, and a static eliminator 20 to erase any charge remaining on the surface.

Incidentally, this embodiment is configured to include a pulse generating means that generates pulses at a predetermined period as the latent image carrier rotates. That is, the dielectric drum 1
As shown in FIG. 10, an encoder 22 as a pulse generating means is attached to its rotating shaft 2l.
The encoder 22 detects the rotational speed or position of the dielectric drum l.

As shown in FIG. 11, the encoder 22 is fixed to a rotating shaft 21 of a dielectric drum l, and has slits 2 3 a, 2 3 a . . . at a predetermined pitch on its outer periphery.
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 Nox signal synchronized with the passage of a.

The encoder 22 detects the rotation of the rotating disk 23 fixed to the rotating shaft 21 of the dielectric drum I using 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 or position of the dielectric drum l is detected.

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 to drive the electrostatic recording head 2 based on the print data held in the image buffer 28; 30 is the drive electrode 4 of the electrostatic recording head 2, and the control electrode 5; , 5, etc., a drive circuit that applies a predetermined voltage to drive the encoder 2, and 31 is the encoder 2.
2 shows control circuits for controlling timing signals for driving the electrostatic recording head 2 in accordance with signals from the electrostatic recording head 2.

FIG. 12 further shows the configuration of the control circuit in detail. In the figure, 32 is a timing signal generation circuit that generates a predetermined timing signal, and 33 is a pulse width of a pulse voltage applied to the drive electrodes 4, 4, etc. and control electrodes 5, 5, etc. of the electrostatic recording head 2. 34 is a pulse width setting circuit for setting Tw; 34 is a T/n period measuring circuit for measuring the period T of the pulse signal output from the encoder 18 based on the reference clock; and 35 is a T/n period measuring circuit for calculating 1/n of this period T; T/n measured by the T/n period measuring circuit 34
A subtraction circuit that subtracts the pulse width Tw set by the pulse width setting circuit 33 from the period; 36 is an FTF memory circuit that outputs signals in the order in which they are first stored; and 37 is a FIFO memory circuit that This is an n-line setting circuit that determines how many lines (n) the signal is output after being delayed from the pulse signal that is sequentially inputted from the encoder 22.

The output pulse 40 from the encoder 22, the output signal 41 from the pulse width setting circuit, and the output signal 42 from the FIFO memory circuit 36 are all sent to the timing generator 2.
9 is output.

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 controlled by the control circuit 31 as follows. That is, as shown in FIG. 12, the control circuit 31 measures the period T of the pulse signal 40 output from the encoder 22 based on the reference clock using the T/n period measuring circuit 34, and also measures the period T of the pulse signal 40 output from the encoder 22 based on the reference clock. A T/n period corresponding to 1/n of the period T of 40 is calculated. Then, the T/n period measurement circuit 34 determines the T/n period of the pulse signal 40 from the encoder 22.
The n-period signal is input to a subtraction circuit 35, and is subtracted by the subtraction circuit 35 from the pulse width TW set in advance in the pulse width setting circuit 33 to obtain the interval Td between pulse signals. The interval Td between these pulse signals is determined by the FIFO
It is sent to the memory circuit 36 and stored once, and this FIFO
The signals are outputted from the memory circuit 36 in the order in which they were first stored. At this time, the signal 42 outputted from the FIFO memory circuit 36 is inputted sequentially from the encoder 22.
The pulse signal 40 is output with a delay of the number n of lines set by the n line setting circuit 37. In addition, along with the interval Td between the pulse signals,
The pulse width Tw preset in the pulse width setting circuit 33 and the output pulse T from the encoder 22 are output to the timing generator 29.

Therefore, in this timing generator 29, based on the interval Td between pulse signals sent from the control circuit 31, the pulse width Tw preset in the pulse width setting circuit 29, and the output pulse T from the encoder 18, The print data timing is generated as follows.

That is, as shown in FIG. 13, 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 Then, the drive electrode signal 38 is transmitted to the first drive electrode 4 in synchronization with the rise of the output pulse T from the encoder 22.
The first and second drive electrodes 42, the third drive electrode 43, and so on are sequentially turned on. At this time, the drive electrode signal 38 is not simply turned on sequentially based on a preset pulse width, but is turned on in synchronization with the rise of the output pulse T from the encoder 22. is turned on by the pulse width Tw, but after that, when the interval Td between the pulse signals sent from the control circuit 3l has elapsed, the second drive electrode signal 382 is turned on by the pulse width Tw. . Thereafter, the same process is repeated to print the l-line 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, as shown in FIG. 12, the interval Td between the pulse signals sent from the control circuit 31 is a value T/ which is obtained by dividing the period T of the pulse signal from the encoder 22 into n equal parts.
It is obtained by subtracting the pulse width Tw from n. Therefore, the value obtained by adding the pulse width Tw and the interval Td between pulse signals and multiplying by n is equal to the period T of the pulse signal from the encoder 22, that is, (Tw+Td)Xn=T. Therefore, even if the period T of the pulse signal from the encoder 22 changes due to uneven rotation of the dielectric drum l, the head drive signal 38, 39 always changes according to the change in the period T of the pulse signal from the encoder 22. Moreover, since the pulse signal is outputted so as to match the period T, even if the period T of the pulse signal from the encoder 22 changes, the recorded electrostatic latent image will not be disturbed.

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; an encoder 22 that generates pulses at a predetermined period T as the dielectric drum 1 rotates; A timing generator 29 generates a pulse for controlling the output of the electrostatic recording head 2 based on the period of the pulse T, and a timing generator 29 generates a pulse for controlling the output of the electrostatic recording head 2 based on the period T of the pulse output from the encoder 22. Since it is configured to include a control circuit 31 that controls a drive electrode signal 38 and a control electrode signal 39, the rotational speed of the dielectric drum 1 is detected by an encoder 22, and the pulses output from this encoder 22 are detected. Based on the period T of the control circuit 3
1 to control the output of the drive electrode signal 38 and control electrode signal 39 output from the timing generator 29,
Even if the rotational speed of the dielectric drum 1 changes due to the recording paper 17 passing through the nip between the dielectric drum 1 and the pressure roller 18 that is in pressure contact with the dielectric drum 1, the rotation of the dielectric drum 1 is always maintained. The electrostatic recording head 2 can be driven in synchronization with the speed. Therefore, it is possible to record high-quality images without causing disturbances in the recorded images.

FIG. 14 shows another embodiment of the present invention, in which the same parts as in the previous embodiment are given the same reference numerals. Even if the speed is higher than the current speed and the cycle T of the pulses output from the encoder becomes shorter than a predetermined value, all drive signals can be output to the electrostatic recording head.

That is, when the rotational speed of the dielectric drum l becomes higher than a predetermined speed and the period T of the pulse outputted from the encoder 22 becomes shorter than a predetermined value, the pulse width Tw is constant, so the timing generator 29 Even if the interval Td between the pulse signals output from the encoder 22 is set to zero, all drive signals cannot be output during the period T of the pulses output from the encoder 22, as shown in FIG. 15(b). This will result in cracks, etc. in the recorded image.

Therefore, in this embodiment, even if the period T of the pulses 40 output from the encoder 22 becomes shorter than a predetermined value, all drive signals are output during the period T of the pulses output from the encoder 22. In order to make this possible, the pulse width Tw and the interval Td between pulse signals are changed depending on whether l/n of the period T of the output pulse from the encoder 22 is less than or equal to a predetermined value.

FIG. 14 is a block diagram showing the control circuit.

In the figure, 50 is a limit setting circuit that sets a value TO that determines whether the circuit of this embodiment is activated when the period T of the output pulse from the encoder 22 becomes less than a predetermined value TO, and 51 is this limit setting circuit 50. The value set to TO
TO/n table conversion circuit that calculates the value of 1/n,
52 is a comparator that compares the value T/n outputted from the T/n period measuring circuit 34 and the value TO/n outputted from the previous To/n table conversion circuit 5l;
Reference numeral 3 designates a selector that switches between the first pulse width setting circuit 54 and the second pulse width setting circuit 55 based on the output from the comparator 52.

In this embodiment, when a pulse output from the encoder 22 is input to the control circuit 31, 1 of the period T of this pulse is input.
/n is measured by the T/n period measuring circuit 34, and this value T/n is set in the limit setting circuit 50 by the comparator 52 and compared with the value TO/n converted by the TO/n table conversion circuit 51. and the value T
If /n is greater than the value TO/n, comparator 5
2, the selector 53 selects the first
The pulse width setting circuit 54 of FIG. It is driven as shown in .

On the other hand, when the value T/n is less than or equal to the value TO/n, the selector 53 selects the second pulse width setting circuit 55 based on the output signal from the comparator 52. Pulse width Tw2 set to
The electrostatic recording head 2 is driven by. This pulse width Tw2 is set shorter than the pulse width Twl set in the first pulse width setting circuit 54.

By doing this, even if the period T of the pulse 40 output from the encoder 22 becomes shorter than a predetermined value, the pulse width of the pulse that drives the drive electrode 4 etc. can be changed as shown in FIG. 15(c). The pulse width Tw2 is shorter than normal.
and set the interval T between pulses accordingly.
By shortening d2, all the head drive signals can be output during the period T of the pulses output from the encoder 22, and it is possible to prevent defects from occurring in the recorded image.

Other configurations and functions are the same as those of the previous embodiment, so
The explanation will be omitted.

〔Effect of the invention〕

This invention has the structure and operation described above, and when the rotational speed of the latent image carrier changes due to, for example, the recording member entering the nip between the latent image carrier and the pressure roller that is in pressure contact with the latent image carrier, However, by controlling the driving timing of the electrostatic recording head, it is possible to provide an electrostatic recording method and an apparatus thereof that can record high-quality images without causing image disturbance.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the principle of the electrostatic recording method according to the present invention, FIG. 2 is a configuration diagram showing an electrostatic recording apparatus to which the electrostatic recording apparatus according to the present invention can be applied, and FIGS. The figure is a plan view and a cross-sectional view showing the ion generation section of the electrostatic recording head.
6 are a sectional view and a plan view showing the electrostatic recording head, FIG. 7 is a sectional view showing the operation of the electrostatic recording head, and FIGS. 8 and 9 are sectional views showing the recording operation of the electrostatic recording head. 10 is a perspective view showing the end of the dielectric drum, FIG. 11 is a configuration diagram showing the encoder, FIG. 12 is a block diagram showing the control circuit, and FIG. 13 is a diagram showing the operation of the control circuit. 14 is a block diagram of a control circuit showing another embodiment of the present invention, and FIG. 15(a) is a timing chart shown in FIG.
(b) and (c) are timing charts showing the operation of the same embodiment, FIG. 16 is a configuration diagram showing a conventional electrostatic recording device, and FIG. 17 and FIG. 18 are ion generating parts of the electrostatic recording head. 19 and 20 are plan views and sectional views showing the electrostatic recording head, FIG. 21 is a sectional view showing the operation of the electrostatic recording head, and FIGS. 22 and 2
3 is a timing chart and explanatory diagram showing the recording operation of the electrostatic recording head, and FIG. 24 (A). (B), (C
) are explanatory diagrams showing the state in which recording paper passes through the nip portion between the dielectric drum and the pressure roller, FIG. 25 is a graph showing fluctuations in the rotational speed of the dielectric drum, and FIG. 26 is an explanatory diagram showing the recording operation. , FIG. 27 is an explanatory diagram showing a recorded image. [Explanation of symbols] ■... Dielectric drum 2... Electrostatic recording head 4... Drive electrode 5... Control electrode 11... Opening 22... Encoder 31... Control circuit 34 ...T/n period measuring circuit 35...Subtraction circuit patent Applicant: Fuji Xerox Co., Ltd. Agent: Patent attorney: Tomohiro Nakamura (1 other person) b Fig. 4 12 Fig. 6 Fig. 7 Fig. 8 Figure 9 Figure No1c No2 ( No3 ( N Figure 18 Figure 19 Figure 109 Figure 20 Figure 23 Figure 24 (A) (8) (C) Figure 25 Time T

Claims (4)

[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 an image, the rotational speed of the latent image carrier is detected, and the driving timing of the electrostatic recording head is adjusted according to the change in the rotational speed of the latent image carrier. An electrostatic recording method characterized by controlling. (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 bearing member, a pulse generating means for generating pulses at a predetermined period as the latent image bearing member rotates, and output control of the electrostatic recording head based on the period of the pulse output from the pulse generating means. output control pulse generation means for generating a pulse for output control; and control means for controlling output of the output control pulse from the output control pulse generation means based on a period of the pulse output from the pulse generation means. An electrostatic recording device characterized by: (3) The control means measures the period of the pulse output from the pulse generation means, and 1/n of the measured pulse period (where n is a number characterizing the matrix of the electrostatic recording head). 1/n period measuring means for calculating the 1/n period measuring means, and subtracting the pulse width of the predetermined output control pulse from the 1/n period measured by the 1/n period measuring means to obtain the output interval of the output control pulse. 3. The electrostatic recording apparatus according to claim 2, further comprising subtracting means. (4) The control means includes a limiter means for outputting an output control pulse according to a predetermined pattern when the period of the pulse output from the pulse generation means is shorter than a predetermined value. The electrostatic recording device according to claim 2, characterized in that: