JPH04323051A - Gradation recording method - Google Patents

Abstract

PURPOSE:To obtain a sufficient gradation number and multigradation by a simple drive circuit. CONSTITUTION:In an electrostatic latent image forming apparatus consisting of ion forming parts A-1, A-2 and an ion lead-out part B, the ion forming parts A-1, A-2 in one dot are provided at least at two or more places and the driving places of the ion forming parts are changed corresponding to input data by a change-over means 1 and the ion lead-out part B is controlled corresponding to the driving of the ion forming parts to perform recording.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gradation recording method for an electrostatic latent image forming apparatus that modulates ion flow to form an electrostatic latent image on a dielectric material.

0002

2. Description of the Related Art In general, the principle of electrostatic recording using an ion flow will be explained with reference to FIG. A developing device 14 is applied to the electrostatic latent image 13.
, a developer such as toner is applied to form a toner image 15 , and the toner image 15 is transferred to the recording paper 17 in the transfer section 16 .
After being transferred, the image is fixed by a fixing device (not shown), thereby performing electrostatic recording. After the recording medium is neutralized by the static eliminating section 18, the remaining developer is removed by the toner removing section 19 in preparation for the next recording.

Conventionally, as an ion current generation method in the electrostatic latent image forming apparatus, there has been a direct electrostatic recording method in which pin-shaped electrodes are arranged in a line and brought into contact with a dielectric material to generate a discharge directly between the dielectric material and the dielectric material. is known, but the gap between the electrode and the dielectric must be maintained with high precision, and there are also drawbacks such as inability to stabilize discharge and wear of the electrode.

Various indirect electrostatic recording methods are known to eliminate the above drawbacks. For example, Figure 7 shows the
This is a method proposed in Japanese Patent No. 101863, in which the corona ion generator 11 has a corona wire 21 built into the shield 20, and the lower part of the ion generator 11 has a
A common electrode 22a and a control electrode 22b are provided with an insulating layer 23 in between, and ions generated in the ion generator 11 are led out from the ion passage hole 24 according to the electric field strength between the common electrode 22a and the control electrode 22b. This is to charge the dielectric material 25.

FIGS. 8(a) and 8(b) show another conventional method, in which a drive electrode 31 and a control electrode 32 are formed with an insulating layer 30 in between, and a screen is further formed with an insulating layer 33 in between. While the electrode 34 is formed, the control electrode 32, the insulator 33 and the screen electrode 34
, an opening 35, a through hole 36, and an opening 37, respectively.
is formed. Then, by applying an AC voltage between the drive electrode 31 and the control electrode 32, positive and negative ions are generated in the ion generation part A near the control electrode 32, and the ions are generated between the control electrode 32 and the screen electrode 34. The ions are emitted from the aperture 37 due to the electric field, and the emitted ions are accelerated by the electric field formed between the screen electrode 34 and the counter electrode to form an electrostatic latent image on the dielectric 38, thereby performing electrostatic recording. .

[0006] When performing gradation recording using the conventional electrostatic latent image forming apparatus described above, the voltage pulse width applied to the control electrode is By changing the dot size, the amount of ions extracted from the aperture was controlled and the size of the dots was changed.

[0007]

[Problems to be Solved by the Invention] However, in the method of controlling the amount of ions extracted and changing the size of the dot by changing the voltage pulse width described above,
Although it is possible to obtain gradation without performing matrix printing such as the conventionally known dither method, it has the problem that it is difficult to sufficiently reproduce highlight areas (dots with a small area). ing.

To explain this in detail with reference to FIG. 5, as shown in FIG. However, the voltage pulse width is Ta
Within a smaller range, the amount of ions extracted has a characteristic of rapidly changing. That is, while the amount of ions in the region [I] can be changed depending on the pulse width, it is extremely difficult to control the amount of ions in the region [II].

Therefore, since the size of the dots formed is approximately proportional to the amount of ions extracted, although it is possible to achieve the gradation of the so-called shadow part with a relatively high density formed in the region [I], it is possible to achieve the gradation of the so-called shadow part with a light density. It is difficult to bring out the tone of the parts. There may be various reasons for this, but one of them is thought to be that switching of high voltage pulses cannot be controlled if it becomes a short pulse. Figure 5
(b) shows the pulse waveform as a function of time, but an accurate rectangular wave cannot be obtained unless the pulse width is greater than (d). Another reason may be that it is extremely difficult to move the ions generated in the ion generation section onto the dielectric material within a very short period of time due to the mobility of the ions.

The present invention solves the above-mentioned problems, and aims to provide a gradation recording method capable of obtaining a sufficient number of gradations and multiple gradations with a simple drive circuit.

[0011]

[Means for Solving the Problems] To achieve this, the gradation recording method of the present invention provides an electrostatic latent image forming device comprising an ion generating section and an ion deriving section, in which ion generating sections are provided in at least two locations in one dot. , the driving location of the ion generating section is changed according to input data, and the ion extracting section is controlled and recorded according to the driving.

0012

[Operation] In the present invention, for example, as shown in FIG.
Two drive electrodes 31 are set for one dot,
By driving each separately by the switching means 1, A
-1 or A-2 alone to generate ions, or A-1,
When the pulse width is modulated by driving both ion generating sections A-1 and A-2 as shown in FIG. 2, [I] The ion amount in the region [II] can be derived, and if the pulse width is modulated by driving either ion generating section A-1 or A-2, the ion amount in the region [II] can be derived. At this time, since the pulse width is larger than Ta, the amount of ions extracted can be changed linearly, and rapid changes in the amount of ions can be controlled unlike conventional methods. There is no need for this, and sufficient gradation changes can be obtained, especially in highlighted areas.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining one embodiment of the gradation recording method of the present invention, FIGS. 2 and 3 are diagrams for explaining the operation of the gradation recording method of the present invention, and FIG. 4 is a diagram for explaining an embodiment of the gradation recording method of the present invention. FIG. 7 is a diagram for explaining another embodiment of the key recording method. In the figure, 1 is a switching means, 31 is a drive electrode, 32 is a control electrode, and A-1 and A-2 are ion generators.

The embodiment shown in FIG. 1 is applied to the electrostatic recording method explained in FIG. 8, and includes a drive electrode 31 and a control electrode 32 with an insulating layer 30 in between,
A screen electrode 34 is formed through an insulator 33, and an opening 35, a through hole 36, and an opening 37 are formed in the control electrode 32, insulator 33, and screen electrode 34, respectively. Then, by applying an AC voltage between the drive electrode 31 and the control electrode 32, the ion generating portion A near the control electrode 32 is
Positive and negative ions are generated in the opening 3 due to the electric field between the control electrode 32 and the screen electrode 34.
The emitted ions are accelerated by the electric field formed between the screen electrode 34 and the counter electrode, form an electrostatic latent image on the dielectric material 38, and perform electrostatic recording.

In this embodiment, two drive electrodes 31 are set for one dot, and the two ion generating sections A-1 and A-2 are driven separately by the switching means 1. It is set up. These ion generating parts A-
1, A-2 is set to A by the switching means 1 according to the input data.
-1, A-2 alone generate ions, A-1, A-
2, both of which are driven to generate ions.

To explain this in detail with reference to FIG. 2, when both ion generating sections A-1 and A-2 are driven to modulate the pulse width, it is possible to derive the amount of ions in the region [I]. [II]
The amount of ions in the region [II] is changed so as to derive the ion amount in the region [II], and this region [II] is the region where dots of the highlight portion with light density are formed. At this time, since a pulse width larger than Ta is used in each case, the amount of ions extracted can be changed linearly, and there is no need to control rapid changes in the amount of ions as in the conventional case, and the It is possible to obtain a wide range of gradation changes.

FIG. 3 explains how the dot size changes according to the gradation recording method of the present invention, and shows the on/off states of the ion generating sections A-1 and A-2 and the voltage pulse width
, 2TW shows that the dot size can be modulated in four stages by combining 2TW. Of course, this is just an example for explanation, and in reality, recording can be done by dividing the pulse width into more fine steps or by increasing the number of ion generating parts. FIG. 4 shows another embodiment of the present invention, which is applied, for example, to the electrostatic recording method described in FIG. 7. In this embodiment, two ion generating units A-1 and A-2 are provided using a corotron with two wires as the ion generating means, and A-1 or A- It is driven so that only A-2 can generate ions, or both A-1 and A-2 can generate ions. Of course, two corotrons themselves may be provided instead of wires.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be modified in various ways. For example, in the above embodiment, two ion generating sections are provided, but the number is not limited to two, and a plurality of drive electrodes may be provided for one dot to form a plurality of ion generating sections. You can also do this. In this case, it is possible to obtain dot sizes with even more gradations.

[0019]

As explained above, according to the present invention, in an electrostatic latent image forming device consisting of an ion generating section and an ion deriving section, the ion generating section is provided in at least two locations in one dot, and input data can be By changing the driving location of the ion generating section accordingly and controlling the ion deriving section according to the driving to record, the following effects can be achieved.

(a) Since the amount of ions can be controlled in sufficient time to switch the amount of ions, the amount of ions can be taken out in accordance with the pulse, and gradation recording with linear characteristics can be performed. Therefore, a sufficient number of gradations and multiple gradations can be obtained.

(b) In particular, the gradation of the highlight portion can be produced smoothly by simple control.

(c) Since it is not necessary to turn on and off high-voltage pulses in an extremely short period of time, the drive circuit can be simplified and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining one embodiment of the gradation recording method of the present invention.

FIG. 2 is a diagram for explaining the operation of the gradation recording method of the present invention.

FIG. 3 is a diagram for explaining the operation of the gradation recording method of the present invention.

FIG. 4 is a diagram for explaining another embodiment of the gradation recording method of the present invention.

[Fig. 5] Diagram for explaining the problems of the conventional gradation recording method

[Fig. 6] Diagram for explaining the principle of an electrostatic latent image forming device

[
FIG. 7: Diagram for explaining a conventional electrostatic latent image forming device

[Fig. 8] Diagram for explaining a conventional electrostatic latent image forming device

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1...Switching means, 30...Insulating layer, 31...Drive electrode, 3
2... Control electrode 33... Insulator, 34... Screen electrode, 35... Opening,
36...Through hole 37...Opening part, 38...Dielectric material, A-1, A-2...Ion generation part B...Ion derivation part.

Claims (2)

[Claims] Claims: 1. An electrostatic latent image forming device comprising an ion generating section and an ion deriving section, in which the ion generating section is provided in at least two locations in one dot, and the driving location of the ion generating section is changed according to input data. , a gradation recording method characterized in that recording is performed by controlling an ion extracting section according to the drive. 2. The gradation recording method according to claim 1, wherein the control in the ion extraction section is performed by changing the applied voltage pulse width.