JPH04333067A - Image recorder - Google Patents

Abstract

PURPOSE:To provide the image recorder where magnetic flux density on a tip of a recording electrode is increased and an image of high quality is obtained by forming a toner image by injecting charge directly from a recording electrode stylus utilizing an electromagnetic toner. CONSTITUTION:A magnetic body 22 is provided on an opposite side of the recording electrode in a magnetic flux generation means 11 feeding magnetic flux to a tip of the recording electrode 5 installed in the vicinity of the recording member 1. The magnetic body 22 is protruded from the magnetic flux generation means in the direction facing the recording member 1 from the tip of the recording electrode 5. The magnetic flux density of the tip of the recording electrode is increased since the magnetic flux of the magnetic flux generation means is deviated to the recording member side, and an image of high quality is obtained.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention uses magnetic toner, for example, conductive magnetic toner (hereinafter abbreviated as toner), and aligns the toner with a magnetic field between a recording electrode needle and a recording member to form a conductive path. The present invention relates to an image recording device that forms a toner image by directly injecting charge from an electrode needle.

0002

2. Description of the Related Art Conventionally, a recording electrode consisting of a cylindrical recording member and a plurality of recording electrode needles spaced apart from each other by a minute distance on the member,
A hopper for depositing conductive magnetic toner is provided upstream of the recording electrode in the recording direction, and supplies the conductive magnetic toner to an area (recording area) consisting of the recording member and the tip of the recording electrode. By aligning the toner between the recording electrode needle and the recording member to form a conductive path using the magnetic field of a magnetic field generating means disposed downstream in the recording direction, and applying a recording voltage to the recording electrode needle according to the image signal. 2. Description of the Related Art An image recording apparatus that forms a toner image is known. Such an image recording apparatus is described, for example, in Japanese Patent Application Laid-Open No. 59-219761.

0003

[Problems to be Solved by the Invention] In order to obtain high image quality using the above-mentioned conventional technology, it is necessary to increase the magnetic flux density in the recording area and strengthen the binding force of the toner that forms the conductive path connecting the recording electrode needle and the recording member. is necessary. In order to increase the magnetic flux density in the recording area, it is necessary to use a magnetic field generating means that is close to the recording electrode and has a high residual magnetic flux density and a large volume.Such a magnetic field generating means increases the weight and cost of the device. This also increases the magnetic flux density of the toner supply section upstream of the recording electrode in the recording direction, forming a strong toner chain in the hopper section, preventing stable toner supply, and causing a decrease in density during continuous recording.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image recording apparatus which increases the magnetic flux density in the recording area while suppressing the increase in the magnetic flux density inside the hopper, and which provides high image quality and less density drop during continuous recording.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention has a recording electrode in which a plurality of electrode needles are arranged perpendicularly to the moving direction of a recording member, and a minute gap between the recording electrode and the recording member. The moving recording member, a hopper that deposits magnetic toner on the upstream side of the recording electrode in the moving direction, and applying a voltage corresponding to an image to be recorded to the recording electrode to charge the toner in contact with the recording member. a drive circuit; a magnetic field generating means for forming a magnetic field in the minute gap on the downstream side of the recording electrode in the moving direction; and a magnetic body provided on a side opposite to the recording electrode of the magnetic field generating means; is made to protrude from the magnetic field generating means in a direction from the tip of the recording electrode toward the recording member.

[0006]

[Operation] The magnetic body provided on the side opposite to the recording electrode of the magnetic field generating means projects from the magnetic field generating means in the direction from the tip of the recording electrode toward the recording member. Since more magnetic flux flows through the magnetic body, the magnetic flux of the magnetic field generating means is concentrated on the recording member side of the magnetic field generating means where the magnetic body protrudes. Since the recording area is located closer to the recording member than the magnetic field generating means, more magnetic flux is supplied to the recording area, and the bond between the toner particles forming the toner chain that electrically connects the recording electrode needle and the recording member becomes stronger. Become. The electrical resistance of the toner chain decreases,
The charge supplied to the toner forming the image increases, and the toner firmly adheres to the recording member. Further, the toner chain is not disturbed by the toner conveying force generated by the rotation of the recording member, and a high-quality toner image can be obtained.

[0007]

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a side view of an image recording apparatus according to the present invention.

The configuration of the embodiment will be explained below. Inside the hopper 6 is conductive magnetic toner (hereinafter abbreviated as toner) 2.
3 is accumulated and stored, and the lowest toner is in contact with the recording member 1.

[0010] The sleeve 13 is made of a hollow non-magnetic material,
It is rotatably supported within the hopper 6 and rotated in the direction of arrow c in the figure by a drive mechanism (not shown).

The magnetic field generating means 12 is a permanent magnet provided in the sleeve 13 and fixed to the main body of the recording device, and is, for example, a ferrite magnet manufactured by Hitachi Metals, Ltd. with a saturation magnetic flux density of approximately 0.4 T (4,000 Gauss). It is YBM-2BD.

The recording electrode 5 includes an electrode substrate 5a made of a non-magnetic insulator, recording electrode needles 5e made of a conductor arranged in a row in a vertical direction on the lower surface of the electrode substrate 5a, and an electrode substrate 5a. The recording electrode needle 5 is placed on the
an integrated circuit 5d to which a recording voltage is applied to e, a protective member 5c made of an insulating non-magnetic material to protect the integrated circuit 5d, and an electrode substrate 5.
The heat sink 5b is made of a non-magnetic material with good thermal conductivity and is fixed to the heat sink 5b.

The cylindrical recording member 1 has a base made of a non-magnetic conductor 1a made of, for example, an aluminum alloy, and a surface made of an insulator 1b made of, for example, an anodic film of aluminum or a coating film of a thermosetting resin. The recording electrode needle 5c is placed with a gap of approximately 20 to 300 μm.

The recording member 1 is rotated in the direction of arrow b in the figure by a drive mechanism (not shown) in a direction perpendicular to the column direction of the recording electrode needles 5e.

The endless belt 3 is located downstream of the recording electrode 5 in the recording direction and close to the recording electrode 5, and is run by a belt guide 20 made of a non-magnetic material and fixed to the drive roller 18 and the main body of the apparatus. It runs in the direction of the arrow a shown in the figure by a drive roller 18 which is supported by a drive roller 18 and rotated by a drive mechanism (not shown).

The second magnetic field generating means 11 includes an endless belt 3
For example, the ferrite magnet YBM-2BD manufactured by Hitachi Metals Co., Ltd. has a saturation magnetic flux density of about 0.4 T, and is a permanent magnet installed inside the recording device and fixed to the recording device main body. Magnetic field generating means 1 for supplying magnetic flux
The same magnetic poles as 2 are placed facing each other. A magnetic body 22 provided on the opposite recording electrode side of the second magnetic field generating means 11 protrudes from the magnetic field generating means 11 in a direction from the tip of the recording electrode 5 toward the recording member 1.

The second magnetic field generating means 11 is located on the downstream side in the recording direction, is close to the recording member 1, is fixed to the recording apparatus main body within the endless belt 3, and has a plurality of magnetic poles in the rotating direction of the recording member 1. A non-image detoning magnet 21 is arranged. The non-image toner removal magnet 21 is a permanent magnet, for example, a ferrite magnet YBM-2BD manufactured by Hitachi Metals, Ltd. with a saturation magnetic flux density of about 0.4 T, and has a plurality of magnetic poles on the side facing the recording member 1. A magnetic field is supplied onto the recording member 1.

The toner conveying magnet 24 is fixed on the belt guide 20 along the inner circumference of the endless belt 3 from the downstream side in the recording direction of the non-image toner removing magnet 21 to near the drive roller 18. The toner conveying magnet 24 has a plurality of magnetic poles perpendicular to the running direction of the endless belt 3, and supplies magnetic flux onto the endless belt 3.

The scraper 8 has one side in contact with the endless belt 3, and the other side is fixed to the top of the recording electrode 5 by means not shown.

The rotating blade 7 is rotated in the direction of arrow e by a drive mechanism (not shown).

On the outer periphery of the recording member 1, a transfer roller 4 for pressing the recording paper 2 onto the recording member 1, a cleaning blade 15 made of a flexible member that contacts the recording member 1 on one side, and a cleaning blade 15 are supported. A support body 14 is provided.

A blade 16 is installed within the discharge toner receiver 17 and is rotated by a drive mechanism (not shown).

A charge eliminating blade 9 is disposed downstream of the cleaning blade 15 in the recording direction, with one side in contact with the recording member 1. The static eliminating blade support 10 is arranged such that the static eliminating blade 9 always contacts the recording member 1 on one side with a constant pressure in the direction in which the recording electrode needles 5e are arranged.

Toner 23 deposited in toner hopper 6
is attracted onto the sleeve 13 by the magnetic field generating means 12. The sucked toner 23 is conveyed to the tip of the recording electrode by the sleeve 13 rotating in the direction of arrow c in the figure, and is deposited on the recording member 1. Therefore, the toner 23 in the hopper 6
Regardless of the amount of toner 23, there is always a sufficient amount of toner 23 on the recording electrode 5.
Since the toner can be supplied to the tip of the toner 23 in the hopper 6 due to toner consumption, there is no effect of changes in the amount of toner 23 deposited in the hopper 6 due to toner consumption or variations in the amount of toner deposited in the hopper 6 in the arrangement direction of the recording electrode needles 5b. The amount of toner 23 supplied to the tip of the electrode 5 is stable and high image quality can be obtained. The toner conveying force generated by the rotation of the recording member 1 and the magnetic attraction force generated by the second magnetic field generating means 11 stably move the toner 23 in the recording direction from the gap between the recording electrode 5 and the recording member 1. Let it flow.

At this time, the driving integrated circuit 5d applies a recording voltage according to the image signal to the plurality of recording electrode needles 5e, selectively charges the toner 23 existing in the gap, and charges are injected. Electrostatic attraction is generated in the charged toner, which adheres to the recording member 1 and becomes image forming toner 23a.

When the non-image toner into which no charge is injected passes through the gap by two forces, the toner transport force and the magnetic attraction force, the magnetic attraction force that overcomes the gravitational field from the second magnetic field generating means 11 causes the non-image toner to move in the direction of the arrow g. It flies toward the second magnetic field generating means 11 as shown in FIG. Second magnetic field generating means 11
The non-image toner remaining on the recording member 1 after overcoming the magnetic attraction from The non-image toner is completely removed from the recording member 1 by minute vibrations caused by the magnetic field, and the non-image toner is removed by the non-image toner removing magnet 2.
Fly towards 1.

The flying non-image toner 23b is attracted onto the endless belt 3 by the magnetic force of the second magnetic field generating means 11 and the magnetic force of the non-image toner removing magnet 21, and as the endless belt 3 runs, it moves in the direction of arrow a. It is conveyed in the direction of , moved onto the scraper 8 by the scraper 8 , and collected into the hopper 6 . The toner transport magnet 24 carries the non-image toner 23
b is held on the endless belt 3 by magnetic force, and the non-image toner 23 is
prevent from falling. The rotary blade 7 rotates in the direction of arrow e to urge the non-image toner 23b to be conveyed onto the scraper 8.

The charged toner 23a forming the image is transferred onto the recording paper 2 by the pressing force of the transfer roller 4 to form an image.

The non-transferred toner 23c remaining on the recording member 1 without being transferred is removed from the recording member 1 by the cleaning blade 15, falls to the end of the discharged toner receiver 17 due to gravity, and is further removed by the screw 16. Due to the rotation, the toner is deposited inside the discharged toner receiver 17.

The charge eliminating blade 9, which is disposed on the downstream side of the cleaning blade 15 in the recording direction with one side in contact with the recording member 1, receives charges from the charged toner 23a forming the image, and the charged toner 23a forming the image is transferred. After removing the residual potential from the non-magnetic conductor 1a of the recording member 1, which still has a residual potential, the static eliminating blade support 10 allows the static eliminating blade 9 to always contact the recording member 1 on one side with a constant pressure in the direction in which the recording electrode needles 5e are arranged. It is arranged like this.

FIG. 2 shows the magnetic field generating means 12, second magnetic field generating means 11, and magnetic body 22 of one embodiment of the present invention shown in FIG.
This figure shows the calculation results of the magnetic flux distribution according to the equation. Figure 3
is a conventional example, and the magnetic field generating means 1 without the magnetic body 22
2 and the second magnetic field generating means 11. The curve in the figure is a magnetic flux curve.

When there is a magnetic body 22 as shown in FIG.
Compared to the conventional example shown in FIG. 3, the number of lines of magnetic force flowing in the direction of the recording member 1 is greater, and the density of magnetic flux supplied to the recording region at the tip of the recording electrode 5 is higher. When the magnetic flux density in the recording area is increased, the bonding force of the toner chain that forms the conductive path connecting the recording electrode needle and the recording member becomes stronger, and the electrical resistance of the conductive path by the toner chain decreases, causing more charge to be transferred to the image forming toner. The adhesion of the image forming toner to the recording member 1 is increased and the image density is increased. Furthermore, the toner chain is not disturbed by the toner conveying force generated by the rotation of the recording member 1, and the clarity of the image is increased and high image quality can be obtained.

In this way, the magnetic body 22 is provided on the opposite recording electrode side of the second magnetic field generating means 11, and the magnetic body 22 is attached to the second magnetic field generating means in the direction from the tip of the recording electrode 5 toward the recording member 1. By protruding from the second magnetic field generating means 11, even if the second magnetic field generating means has the same shape and performance as the conventional one, the magnetic flux density supplied to the recording area at the tip of the recording electrode 5 is increased, so that high image quality can be obtained. Moreover, even if the size is smaller and the performance is inferior to the conventional one, the same image quality as the conventional one can be obtained, and the cost can be reduced.

FIG. 4 shows a second embodiment of the invention, and FIG. 5 shows a magnetic field distribution diagram of the second embodiment of the invention.

The difference from the first embodiment is that the second magnetic field generating means 11 is provided on the opposite recording electrode side of the second magnetic field generating means 11 in the direction from the tip of the recording electrode 5 toward the recording member 1.
The magnetic body 22 protruding from the recording member 1 is bent at the end of the protruding portion so as to be close to the recording member 1 on the downstream side in the recording direction with respect to the second magnetic field generating means 11.

As described above, since the magnetic body 22 is provided close to the recording member 1, the number of lines of magnetic force flowing in the direction of the recording member 1 is larger than that in the first embodiment, and the number of magnetic lines of force flowing in the direction of the recording member 1 is greater than that in the first embodiment. The resulting magnetic flux density becomes higher and higher image quality can be obtained.

[0037]

According to the present invention, a magnetic material is provided on the downstream side in the recording direction of the recording electrodes and on the opposite recording electrode side of the magnetic field generating means that is provided in the arrangement direction of the recording electrodes and generates a static magnetic field. Since the magnetic material is made to protrude from the magnetic field generating means in the direction from the tip of the recording electrode toward the recording member, the recording electrode is The magnetic flux density at the tip can be increased, there is no decrease in black density during continuous recording, and high quality toner images can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an apparatus according to an embodiment of the present invention.

FIG. 2 is a magnetic field distribution diagram of the embodiment shown in FIG. 1.

FIG. 3 is a magnetic field distribution diagram of a conventional device.

FIG. 4 is a sectional view of a device according to a second embodiment of the invention.

FIG. 5 is a magnetic field distribution diagram of the second embodiment shown in FIG. 4;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Recording member, 2... Recording paper, 3... Endless belt, 4... Transfer roller, 5... Recording electrode, 6... Hopper, 9... Static elimination blade, 11... Magnetic field generating means, 12... Second magnetic field generating means, 2
2... Magnetic material, 23... Conductive magnetic toner.

Claims (2)

[Claims] 1. A recording electrode having a plurality of recording electrode needles arranged in a row; a cylindrical or cylindrical recording member that rotates while maintaining a minute gap with the recording electrode; a hopper located upstream in the moving direction of the recording member to deposit conductive magnetic toner; and a magnetic field located downstream in the recording direction of the recording electrodes and provided in the arrangement direction of the recording electrodes to generate a static magnetic field. generating means, by applying a recording voltage to the recording electrode needle in accordance with an image signal, selectively charging the conductive magnetic toner passing through the gap by rotation of the recording member. In an image recording apparatus for obtaining a toner image, a magnetic body is provided on a side opposite to the recording electrode of the magnetic field generating means, and the magnetic body projects from the magnetic field generating means in a direction from the tip of the recording electrode toward the recording member. An image recording device characterized by: 2. The image recording apparatus according to claim 1, wherein the magnetic body is plate-shaped, and the end of the protrusion is located downstream of the magnetic field generating means in the recording direction and close to the recording member.