JPS63136058A - Powder image recorder - Google Patents

Abstract

PURPOSE:To enable high-density recording and halftone recording according to density information on image information by providing a means which varies and controls either or both of the value of a voltage applied to a control electrode and the application time of the voltage according to the density information on the image information. CONSTITUTION:The amount of toner in reciprocal motion depends upon the supply amount of toner on a toner carrier 1, so it is difficult to control picture elements at every picture element and it does not suit to image density control, but when flying speed can be controlled by the intensity of an electric field operating between the control electrode 9 and a toner carrier 1, i.e. the level of the voltage applied to the control electrode 9, the time of the reciprocal motion can be controlled by the pulse width of the pulse voltage applied to the control electrode 9, so image density is controllable by controlling the level and pulse width of the pulse voltage applied to the control electrode 9. The density of printing dots can be controlled according to the density information on the image information by controlling either or both of the voltage value and the application time of the voltage applied to the control electrode 9. Consequently, high-density recording and halftone recording are both enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a powder image recording device that forms a powder image on a recording medium in response to an electrical signal.

[Conventional technology]

Image recording devices using powder include electrophotography, electrostatic recording, etc., which form an electrostatic latent image on a latent image carrier, develop this electrostatic latent image to form a powder image, and A device that transfers this powder image onto a recording medium and fixes the powder image without being transferred onto the recording medium is known and is used in copying machines, printers, facsimile machines, and the like.

In addition, a so-called powder contrast graph in which a pixel electrode, a recording medium, a toner layer, and an electrode are arranged in this order, and a voltage is applied to both electrodes in an imagewise manner to cause the toner to adhere directly to the recording medium to obtain a visible image. Yi is known.

[Problem that the invention seeks to solve]

The former type of powder image recording device requires multiple recording processes such as charging the latent image carrier, forming an electrostatic latent image, developing process, transfer process, and fixing process, so reliability is low. However, maintainability is low, and since equipment for carrying out each process is required, the overall equipment becomes large and expensive.

Furthermore, when converting an input electrical signal according to image information into an electrostatic latent image, it is difficult to continuously control the potential of the electrostatic latent image, and it is not possible to control the dot density in the smallest unit, so it is difficult to control the dot density in the smallest unit. The image density is controlled by the so-called area gradation method, which changes the density of each unit depending on the number of printed dots in each unit, so it can be used for high-density recording (high-density recording) and half-tone recording (intermediate-density image formation). ) cannot be achieved at the same time, and it is not possible to record the density according to the image information.

For example, when recording 64 gradations, the pixel unit is S x 8, so if you want to obtain a resolution of 8 pixels per meter, the minimum unit of printing is a density of 64'74 nm'', that is, Since one recording has a size of 15.625'''μ, it is practically impossible, and either high-density recording or half-tone recording is required, and both cannot be achieved.

In the latter case, images can be formed and recorded in two steps: image formation and fixing, so it is possible to improve maintainability and downsize the device, but on the other hand, the electric field acting on the toner is Since the toner acts between the two electrodes through a medium such as paper, whose characteristics vary greatly depending on the environment, the reliability with respect to the environment is low, and the contact between the recording medium and the toner layer tends to cause fogging on the background. .

In the latter case, the image density changes by changing the voltage and pulse width applied to both electrodes, but this density change is caused by the transfer of individual toner particles forming a single layer on the electrodes to the recording medium. This occurs because some toner is transferred and other toner is not transferred due to variations in the size of the electric field required for this, and toner transfer due to variations in the in-plane characteristics of the recording medium or environmental changes. Even if the same voltage and pulse width are applied, the image density is not necessarily stable due to variations in the ease of application, so even if the applied voltage and pulse width are changed, an image with the desired density cannot be obtained, It is difficult to achieve both density recording and halftone recording.

[Means and actions for solving the problem] A plurality of minute openings and a control electrode for controlling passage of toner through each minute opening are provided between a toner carrier carrying conductive toner and a counter electrode. A toner flight control member is provided, and a voltage is applied to the control electrode according to the image information to cause the conductive toner on the toner carrier to fly toward the control electrode side, and this flying toner is passed through the micro opening 8. A means is provided for controlling either or both the voltage value and the application time of the voltage applied to the control electrode in accordance with the density information of the image information. In addition to being able to perform recording by controlling the voltage application, high-density recording and halftone recording can be performed in accordance with the #open information of the image information.

〔Example〕

FIG. 1 is an explanatory diagram showing an embodiment of a powder image recording apparatus according to the present invention, in which a toner flight control member 2 is provided separated from a toner carrier 1 that carries conductive toner, and this toner flight A counter electrode 3 is provided apart from the control member 2 so that the recording medium 4 moves while being in contact with the counter electrode 3.

The toner carrier 1 has a roll shape and is rotated in the direction of the arrow, and the conductive toner 5 is adhered to the surface in a layer of uniform thickness by the blade member 6 to form a thin conductive toner layer, and the toner carrier 1 is rotated in the direction of the arrow. 1 rotates the toner flight control member 2.
transported to.

As shown in FIG. 2, the toner flight control member 2 includes a large number of minute openings 8 formed at predetermined minute intervals in an insulating support plate 7, and an RF control device installed around the minute openings 8. Each control electrode 9 is connected to a driving voltage applying means 10, so that a voltage is applied to each control electrode 9 in accordance with the electrical signal to be recorded.

The counter electrode 3 has a roll shape and is rotated in the direction of the arrow, and is connected to a voltage applying means 11 to which a voltage is applied.

The recording body 4 is fed a little from the opposite '#1 [3 and the fuser 1z
This is to allow it to pass through and be fixed.

As shown in FIG. 3, the toner flight control member 2 has a large number of minute openings 6 formed in an insulating support plate 7 in a staggered manner, and control electrodes 9 are respectively installed around the openings 6. As shown in the figure, narrow and elongated minute openings 8 are formed in the insulating support plate 7, and controls are formed on both sides of the minute openings 60. ! ! f
f9 may be provided at minute intervals, and the minute apertures 1! The shape of A8 may be polygonal or oval instead of circular, and the shape 9 may be formed to form a toner passage opening for conductive toner corresponding to the size of the printing dock.

Alternatively, the conductive toner 5 may be uniformly and thinly supplied onto the toner carrier 1 using a developing machine used for ordinary electrophotographic development.

The driving voltage applying means 10 applies a pulsed voltage to the control electrode 9 in response to an electric signal based on image information, and the pulse width thereof is controlled by density information of the image information. be.

To record a powder surface image, the toner carrier 1 is rotated in the direction of the arrow to transfer the conductive toner 5 to the toner flight control member 2.
At the same time, the opposing type i3t rotates to move the recording body 4 in the direction of the arrow, and at the same time inputs an electric signal based on the image information to be recorded to the drive voltage applying means 10 and converts it into the electric signal. Accordingly, a voltage is applied to the corresponding control electrode 9 to cause the conductive toner 5 to pass through the minute opening 8 to the recording medium 4.
The particles fly toward and adhere to the surface, thereby forming a visible image, that is, a powder image, on the recording medium 4.

In FIG. 1, reference numeral 13 denotes conductive toner that has passed through the minute opening 8 and adhered to the recording medium 4, ie, a so-called printing dot.

Next, the principle of the powder image forming apparatus according to the present invention is illustrated in FIG.
), (b), and (C).

FIG. 5(α) shows the initial state of recording, in which no voltage is applied to the tab control electrode 9, in which the conductive toner 5 is supported on the toner carrier 1, and the conductive toner 5 and the toner flying The counter electrode 3 is held in a non-contact manner with the control member 2 on the opposite side of the toner carrier 1, and the recording body 4 is in contact with the counter electrode 3, and the counter electrode 3 is held in a non-contact manner with the toner flight control member 2. and are arranged in a non-contact manner.

On the other hand, the toner carrier 1 and the control element 9 are grounded or held at the same potential, and a predetermined voltage is applied to the opposing i-pole 3 by the voltage applying means 11.

Because of this, the electric field formed by the voltage 4 of the counter electrode 3 is shielded by the control electrode 9, hardly acts on the conductive toner 5 on the toner carrier 1, and the conductive toner 5 becomes a toner. It is stably supported on the carrier 1.

From this state, an electric signal is input to drive voltage applying means 1.
When a predetermined pulse voltage a is applied to the control electrode 9 at 0, the conductive toner 5 in the portion facing the control electrode 9 flies as shown in FIG. 5(h).

This is because an electric field is formed between the control electrode 9 and the toner carrier 1 by the voltage Vo applied to the control electrode 9, and this electric field induces charges in the conductive toner 5, thereby exerting electrostatic attraction.

A part of the above-mentioned flying conductive toner 5 passes through the minute opening 8 and is caused to face [ff1] by the electric field formed by the counter electrode 3.
The powder is attracted to the E side and adheres to the recording medium 4 to form printed dots 13, thereby forming a powder image.

On the other hand, the remaining portion of the aforementioned flying conductive toner 5 adheres to the control electrode 9.

The conductive toner 5 attached to the control electrode 9 is controlled by the control 1! The electric field between the pole 9 and the toner carrier 1 induces a charge with a polarity opposite to that described above, and it again flies toward the toner carrier 1 and is carried on the toner carrier 1. Thereafter, the same flight is caused by the control electrode. This is repeated while the voltage Vo is applied to 9.

Then, when the voltage Fa of the control electrode 9 is removed, FIG.
). The pick stick adheres to the recording medium 4 and faces the hole-groove electroconductive toner 5 1! Although the electric field formed by the voltage rm applied to the pole 3 is acting, charge is not injected from the recording medium 4 and does not return to the control point 9 side.

On the other hand, since the electric field between the control electrode 9 and the toner carrier 1 disappears, the control electrode 9 and the toner carrier 1! The conductive toner 5 remains attached thereon in accordance with the state when the voltage Vo is removed.

Then, when voltage 0 is applied to the control electrode 9 again, the above-mentioned operation is performed, but at this time, control 1! The electroconductive toner 5 remaining on the pole 9 flies back to 10% of the toner carrier due to the electric field between the control vit and the handle q and the toner carrier 1, so the conductive toner 5 is integrated into the control [Q9]. It will not accumulate and will remain stable even if powder images are repeatedly formed.

Therefore, a large amount of conductive toner ε does not adhere to and accumulate in the minute openings 8, and the minute openings 8 do not allow conductive toner ε to accumulate.
Since there is no clogging, continuous and stable powder image recording can be performed.

That is, the conductive toner 5 is repeatedly induced and caused to fly between the control ffi pole 9 and the toner carrier 1 by the action of the electric field formed between the control ffi pole 9 and the toner carrier 1. It is possible to prevent the conductive toner 5 from adhering to the minute openings 2 and clogging them, thereby making it possible to continuously and stably record powder images.

On the other hand, if a high-resistance or insulating toner is used, the electrostatic field formed between the control MJt and the toner carrier may not induce charge in the toner, or the time required for induction will be longer, resulting in the formation of a powder image. The toner cannot be repeatedly ejected within the time required, and the toner adhering to the control electrode by being ejected by the electric charge generated by frictional charging, etc., is deposited on the control electric machine in a blue color after the powder image formation is completed. However, during continuous and repeated image recording, the minute openings become clogged, making it impossible to record stable powder images and reducing reliability.

Note that by applying an alternating electric field between the control electrode 9 and the toner carrier 1 by changing the voltage applied to the control electrode 9 to alternating current, the aforementioned toner can fly between the control electrode 9 and the toner carrier 1 and return. You can also do this, but if you do it like this,
Not only does the drive for applying alternating current become complicated,
This is difficult in practice because it is necessary to align and sufficiently control the charges of the toner.

This is because while conductive toner induces a false charge necessary for flight, the above-mentioned high-resistance or insulating toner that is triboelectrically charged: ri, whose ′α charge is This is because even if the electric field acting on the toner is constant, there will always be toner that can fly and toner that cannot fly depending on the magnitude of the charge.

Furthermore, the amount of charge in charged toner tends to fluctuate depending on the environment, especially humidity, which causes a loss of operational stability.
In the case of a four-electrode toner, the change in resistance due to moisture absorption does not cause any difference in the amount of induced charge, so the operation is stable.

In the above recording operation, the conductive toner 5 is
Since the voltage applied to the control electrode 9 is controlled by the electric field caused by the voltage applied to the toner carrier 1, the electric field acting between the control electrode 9 and the toner carrier 1 is 5
It is desirable that the voltage is V/m or more.

This is because, as described above, each repetition of the conductive toner is caused by the induced injection of charge from the control '#tN9 into the conductive toner and the external electric attraction force acting on the charge. Ring groove conductive toner (17: Does it work? rP
This is because the ff attractive force is large and the flight of the conductive toner is ensured.

Mana, use conductive toner! 10"0c to ensure prompt induction and injection of the tlα load.
It is desirable that the conductive toner has a low resistance of m or less.

Please note that the printing drum formed on the recording body 4), the S degree of I3, and the image density are determined by the amount of toner that passes through the minute opening 8, and this amount of passing is determined by the amount of toner that passes through the control electrode 9 and the toner carrier 1. Toner L flight speed, reciprocating motion between! Since it is determined by the time for repeating vJ, image density can be controlled by controlling these.

The toner particles that move back and forth in these thick blades depend on the amount of toner supplied on the toner carrier 1, making it difficult to control each pixel and not suitable for image density control, but the flying speed can be controlled. It can be controlled by the magnitude of the electric field acting between the electrode 9 and the toner carrier 1 and the magnitude of the voltage applied to the control electrode 9, and the time for reciprocating movement can be controlled by the pulsed voltage applied to the control electrode 9. Since the width of the pulse voltage applied to the control tff19 can be controlled by the width of the pulse,
Image density can be controlled by controlling the pulse @.

FIG. 6 shows the recording apparatus shown in FIG. 1, in which the distance between the control electrode 9 and the toner carrier 1 is 200μ, the diameter of the minute opening 8 is 100μ, conductive toner having a resistance of 106 Ωcm is used, and the control electrode 9 is The results show that the density of the printed dots 13 was measured by changing the magnitude and pulse width of the applied voltage, and the results show that the larger the voltage and the wider the pulse width, the darker the density of the printed dots 13 changes continuously. I understand. The density of the printed dots is expressed as optical j vs. density.

In this way, by controlling either or both of the voltage value and pulse width of the pulsed voltage applied to the control t(if'?) according to the density information of the image information to be recorded, the image density can be adjusted to the density information of the image information. It is possible to control the value accordingly, satisfy both high-density recording and half-tone recording, and easily record images with gradation faithfully.

Therefore, in the six embodiments of the present invention described above, the pulse width of the pulsed voltage is controlled, but this is because the pulse width gain a1 is easier than controlling the voltage value.

The pulsed voltage may have a continuous rectangular waveform as shown in FIG. 7(α), or may have a trapezoidal waveform as shown in FIG. 7(b). It is also possible to form a set of repeated pulses with a shorter width as shown in FIG. 7(c), and control the number of repeated pulses.

FIG. 8 shows another embodiment, in which the counter electrode 3 has a silicone rubber layer 3b on the surface of the roll-shaped main body 3α, and a heater 21 is provided in the hollow cylindrical elastic body @20. The recording apparatus has a built-in heat roll 22 which is pressed against the counter electrode 3, and the recording medium 4 is passed through the nip thereof, and the other configuration is the same as that of the recording apparatus of the first embodiment.

In such a recording device, the toner that flies to the silicone rubber layer 3b of the counter electrode 3 and passes through the minute opening 9 adheres to the printing dot 13, and this printing driver)+3 comes into pressure contact with the heat roll 22. The image is transferred to the recording medium 4 by force and heat, and the image density is controlled in the same manner as described above.

〔Effect of the invention〕

Since an image can be formed and recorded on the recording medium simply by applying a voltage to the control electrode 9 in accordance with the image signal, there is no need for multiple recording steps as in the past, improving reliability and maintainability. The device is small and inexpensive.

Also, control t! The electric field formed between the temporary electrode 9 and the toner carrier 1 causes the conductive toner 5 on the toner carrier 1 to fly, so recording can be controlled by controlling this electric field. It is possible to have a wide interval between the recording bodies 4 and the tolerance thereof, which makes it easy to configure the recording apparatus, and there are also extremely small restrictions on the thickness and type of the recording body 4.

Sixth, since a uniform electric field is sufficient for the control electrode 9 and the counter electrode 3, even when plain paper is used as a recording medium, good recording is possible without being affected by the drop in resistance due to water content and the diffusion of the electric field. can be done.

Furthermore, since the recording medium 4 is not in contact with the conductive toner, no background capping occurs on the recording medium 4 at all.

Maroku, system? KJ1! By changing the voltage applied to the pole 9, the number of toner passing through the minute opening 8 can be controlled, so the image density can be easily controlled and gradation recording can be easily performed.

Furthermore, since the density of the printed dots can be controlled according to the density information of the image information by controlling either or both the voltage value and the application time of the voltage applied to the control electrode 9, high-density recording and halftone recording can be achieved. can be achieved at the same time.

Furthermore, since the toner is ejected and reciprocated by a sufficiently large electric field acting between the control electrode 9 and the toner carrier 1, the toner changes the image density even if there is a change in the ease with which the toner is ejected. The reciprocating movement is sufficient to prevent the toner from causing any damage, and since variations in the in-plane characteristics of the recording medium also exist on the opposing electrode 3 side, there is no influence on the reciprocating movement of the toner and the amount of toner passing through the minute apertures 8. .

Therefore, if the application time is the same and the voltage value is the same, the density of the image on the recording medium 4 is extremely stable, and the image information I! !
! High W according to degree information! To accurately and stably perform degree recording and halftone distribution.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 is an overall view, FIGS. 2, 3, and 4 are front views showing different embodiments of the toner flight control member, and FIG. 5(a). Ch), (C) is an explanatory diagram of the operation, Fig. 6 is a rotation diagram showing the relationship between applied voltage value, pulse width, and density of printed dots, and Fig. 7 is an illustration of the operation.
Figures (α), (h), and (C) are waveform explanatory diagrams of pulsed voltages to be printed, and Fig. 8 is an overall diagram of an example of a song. 1 is a toner carrier, 2 is a toner flight control member, 3 is a counter electrode, 4 is a recording body, 5 is a conductive toner, 8 is a minute opening, and 9 is a control voltage.

Claims (1)

[Claims] Toner carrier 1 carrying conductive toner 5 and counter electrode 3
A toner flight control member 2 having a plurality of micro-apertures 8 and a plurality of control electrodes 9 for controlling passage of toner through each micro-aperture 8 is disposed between the control electrodes 9 and 9 in accordance with image information. A voltage is applied to cause the conductive toner 5 on the toner carrier 1 to fly toward the control electrode 9 side, and the flown conductive toner passes through the minute opening 8 and transfers to the counter electrode 3 side to form a recording medium. In a powder image recording device that forms an image by depositing the powder on the control electrode 9, means for controlling changes in either or both of the voltage value and voltage application time of the voltage applied to the control electrode 9 according to the density information of the image information. A powder image recording device characterized by being provided with.