JPH0359691A - Recording device - Google Patents

Abstract

PURPOSE:To obtain a high-density image without unevenness by forming a 1st magnetic latent image in which magnetizing directions are alternately inverted by a 1st specified length for a master image and superposing and forming a 2nd magnetic latent image in which the magnetizing directions are alternately inverted by a 2nd specified length which is shorter than the 1st length on the 1st latent image. CONSTITUTION:In the case of magnetizing the master image 52 formed on an image carrier 14, the 1st magnetic latent image in which the magnetizing directions are alternately inverted by the 1st specified length l1 is formed and also the 2nd magnetic latent image in which the magnetizing directions are alternately inverted by the 2nd specified length l2 which is shorter than the 1st length l1 is superposed and formed on the 1st latent image, then the superposed magnetic latent image is developed with magnetic developer T2. Therefore, the 1st magnetic latent image acts so that the practical adhesive quantity of the magnetic developer T2 may be obtained and the 2nd magnetic latent image acts so that the magnetic developer T2 may uniformly adhere, thereby accomplishing the compatibility of the adhesive quantity and the uniform adhesion of the developer T2. As for the copied image on a recording paper, the density of image quality is high, the density is uniform and the quality is made high.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a recording device used as, for example, a copying machine or a printer.

(Prior Art) Conventionally, electronic copying machines, plate making/printing devices, and the like have been known as recording devices for copying manuscripts. In general, electronic copying machines are easy to set up for copying operations and are easy to handle. In contrast, plate-making and printing equipment can create a master plate from a manuscript and use this master plate to repeatedly transfer onto recording paper as a transfer material, so once the master plate is created, it can print at high speed. This has the advantage that the larger the number of copies made from the same original document, the lower the printing cost.

By the way, with conventional plate making and printing equipment, when the number of copies made from the same manuscript is less than that of a child actor, the original plate accounts for a large proportion of the total printing cost, so the printing unit cost is higher than that of an electronic copying machine. This method has the disadvantage that it takes time and effort to set up the work because it requires the process of creating an original plate. On the other hand, electronic copying machines repeat processes such as charging, exposing, developing, and removing static electricity each time they make a copy of a single document, so the printing price per page does not decrease even if the number of copies made from the same document increases. However, the copying speed is considerably slower than that of a printing machine.

To deal with these problems, electronic copying machines have come into practical use as an extension of conventional technology, capable of copying at a speed closer to that of printing, and without requiring the skilled work and setup required by printing machines. It is becoming more and more popular.

However, in order to increase the copying speed even higher, the power required for exposing the original, fixing the developer, charging, etc. becomes extremely large, so it is necessary to use a normal commercial power supply (100V, 15A).
There are problems in that the image quality is sacrificed due to not being able to use the image processing system, or unreasonable development speed, etc.

In order to solve these problems, the present inventors formed a master image made of a permanently magnetizable master material and corresponding to the image to be reproduced on a photoreceptor as an image bearing means, and The image is magnetized with a magnetizing means such as a magnetic head to form a magnetic latent image to form a printing original plate, and the magnetic latent image formed on this master image is developed with a magnetic developer to create a printing plate on the master image. He invented a recording device that obtains a developer image with the same shape as a master image and transfers this developer image onto recording paper for recording.
No. 273 and Japanese Patent Application No. 63-29274). With this recording device, multiple copies of the same original can be made at high speed, just like a printing machine, using simple operations similar to those of conventional electronic copying machines.Moreover, each time a copy is made, the master image forming process, that is, charging, exposure, Since there is no need to repeat static elimination, etc., power consumption can also be reduced.

Incidentally, the master image in the above-mentioned recording device is produced by developing an electrostatic latent image formed on a photoreceptor such as zinc oxide using an electrophotographic method using a developer having magnetic properties that can be permanently magnetized. An image is created by fixing it on the photoreceptor, and the master image fixed on the photoreceptor is magnetized by magnetizing means such as a magnetic head to form a latent image, which is used as a printing original plate. Then, as shown in FIG. 17, the magnetization by the magnetization means is performed such that the magnetization direction is alternately reversed over a constant length g, so that the magnetization is performed between the magnetization reversal parts M whose magnetization directions are reversed. A loop of leakage magnetic flux is created, and the magnetic developer for image formation other than the one for forming the master image supplied onto the master image (on the magnetic latent image) is chained along this loop of leakage magnetic flux. A developer image 53 having the same shape as the master image is obtained.

Then, recording is performed by transferring this developer image 53 onto recording paper.

However, in the above recording apparatus, during the printing process, the amount of magnetic developer T2 that adheres to the master image 52 on which the magnetic latent image is formed is small, and therefore the density of the image finally obtained on the recording paper is small. There was a problem that the value was low.

That is, the magnetic developer T2 adhering to the master image 52
The amount depends on the magnetic performance of the master image 52, but it also depends largely on a certain length when the magnetization direction is alternately reversed over a certain length, that is, the recording pitch ρ. 18th
The figure shows a volume average particle size of approximately 11 μm as magnetic developer T2.
The recording pitch D when the magnetic latent image on the master image 52 is developed with the magnetic toner of 2 and the attachment HEk m of the magnetic toner T2 developed on the master image 52. It shows the relationship with □. As is clear from the figure, the recording pitch g is approximately 20
Up to 0 μm, the amount of attached magnetic toner T2 increases as the recording pitch D becomes longer.

Therefore, magnetic toner T with which practical image density can be obtained
Since the adhesion fiTH of 2 should be about 1.25 mg/cJ or more, this adhesion ff11.25 / cI
In order to obtain #, it is sufficient to set the recording pitch g to approximately 70 μm or more. However, according to experiments,
When the recording pitch g is 70 μm, the developed magnetic toner T2
As a result, the image obtained on the recording paper had significant density unevenness. The adhesion unevenness of the developed magnetic toner T2 is a stripe-like unevenness corresponding to the recording pitch g of the magnetic latent image. This is caused by a decrease in the amount of adhesion between portions M. moreover,
When the recording pitch is 200 μm or more, the magnetic toner T2 adheres only to the vicinity of the magnetization reversal portion M of the magnetic latent image.
The amount of toner M decreases rapidly. On the other hand, as is clear from FIG. 18, in order to obtain a uniform adhesion state that does not cause density unevenness, that is, development unevenness, it is sufficient to set the recording pitch g to about 30 μm or less, but in this case, the magnetic toner T2 The amount of adhesion was extremely small and a practical concentration could not be obtained.

(Problems to be Solved by the Invention) The present invention has been made in view of the above circumstances, and has a high density equivalent to that of an electrophotographic copying machine, and
It is an object of the present invention to provide a recording device capable of obtaining uniform images and capable of copying multiple sheets from the same original document at high speed using a simple process similar to a printing machine.

[Structure of the Invention] (Means for Solving the Problems) A recording device of the present invention includes an image carrier, a master image forming means for forming a permanently magnetizable master image on the image carrier, and a master image forming means for forming a permanently magnetizable master image on the image carrier. a first magnetic latent image forming means for forming a first magnetic latent image in which the magnetization direction is alternately reversed over a first predetermined length on a master image formed by the forming means;
A second magnetic latent image, the magnetization direction of which is alternately reversed, is superimposed on the master image on which the first magnetic latent image is formed by the magnetic latent image forming means by a second predetermined length shorter than the first predetermined length. developing the first and second magnetic latent images formed by the first and second magnetic latent image forming means to overlap the master image with a magnetic developer; The present invention is characterized in that it comprises a developing means for doing so, and a transfer means for transferring a developer image obtained on the master image by the developing means to a transfer material.

(Function) When magnetizing a master image formed on an image carrier, the present invention forms a first magnetic latent image in which the direction of magnetization is alternately reversed over a first predetermined length; A second magnetic latent image having a second predetermined length shorter than the first predetermined length and whose magnetization direction is alternately reversed is formed to be superimposed on the magnetic latent image. A magnetic latent image is formed in which a first magnetic latent image having a length and a second magnetic latent image having a second predetermined length overlap, and this overlapping magnetic latent image is developed with a magnetic developer. Therefore, the first magnetic latent image acts to obtain a practical adhesion amount of magnetic developer, and the second magnetic latent image acts to ensure that the magnetic developer adheres uniformly, thereby increasing the amount of developer. Both the amount of adhesion and the uniform adhesion of the developer can be achieved, and the reproduced image obtained on the recording paper has high image quality and density, and is uniform in density and high quality.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a recording apparatus of the present invention. This recording device obtains a first toner 11 (master image) made of a first magnetic toner by electrophotography, forms a magnetic latent image thereon, and then develops this magnetic latent image with a second magnetic toner. Then, a second toner image is obtained, and this second toner image is transferred onto recording paper for recording.

In FIG. 1, 1 is a drum around which a photoreceptor belt 14 is wound.
Along the direction of arrow A in the figure, a charging charger 2, an exposure optical system 3, a first developing device 4 containing a first magnetic toner T1, a first toner image fixing device 5 consisting of a flash lamp, a first toner image fixing device 5, A second developing device 6 containing the second magnetic toner T2, a pre-transfer charger 7, a transfer charger 8, and two magnetic heads 9 and 23 that magnetize the first toner image to form a magnetic latent image are arranged in sequence. It is set up.

A photoreceptor belt 14 serving as an image carrier is wound around the outer circumference of the drum 1 so as to surround the circumferential surface of the drum 1 . The photoreceptor belt 14 includes a photoreceptor layer 14a for forming an electrostatic latent image on its surface portion (the side facing the exposure optical system 3). The photoreceptor layer 14a is made of a dielectric material such as zinc oxide, which has been sensitized to long wavelengths with a dye such as rose bengal in order to have sensitivity in the visible range, for example. Each time the original to be copied changes, the photoreceptor belt 14 is newly added to the supply roll 1 by a predetermined size.
5 onto the drum 1, and the used portion is wound up by a winding roll 16.

The drum 1 is configured to rotate in the direction of arrow A in the drawing at at least a first speed v1 and a second speed v2 by a drive mechanism (not shown). For example, the first speed v1 of the peripheral surface of the drum 1 is 10 to 150 mm/see.
, a speed of 500 mm/see or more is selected as the second speed v2 and driven.

The exposure optical system 3 guides reflected light 3a from a light source reflected by a document, for example, and forms an image on a photoreceptor belt 14 wrapped around the drum 1, thereby forming an electrostatic latent image on the photoreceptor belt 14. It is something that forms.

The first magnetic head 9 and the second magnetic head 23 are each composed of a single track head having a length corresponding to the entire width of the photoreceptor belt 14, that is, a recording track width that can cover the width of the image area. be. These two magnetic heads 9° 23 are disposed so as to be movable in the direction of the arrow CD in the figure, and are set to move in the direction of the arrow C in the figure to approach the photoreceptor belt 14 during a master image forming process to be described later. During the printing process, it moves in the direction of the arrow in the figure and waits away from the photoreceptor belt 14.

The first magnetic head 9 and the second magnetic head 23 have the same configuration except for the size of the front gap. FIG. 12 is a schematic side view of the first and second magnetic heads 9.23, which are equipped with a core 31 having a single recording track width and a coil 32 wound around this core 31. . A gap gI (gz) is formed on the surface of the core 31 facing the photoreceptor belt 14, and the magnetic flux generated in this gap g+ (g2) causes the photoreceptor heald 1 to
The first toner image 51 formed on the toner image 4 is magnetized. El (E2) is a power source for passing current through the coil 32, and this power source El (E2) outputs an alternating square wave voltage Wl (W2) of a predetermined frequency.
) is supplied to the coil 32.

Further, the recording paper P as a material to be transferred is stored in the paper feed cassette 45.
The sheets are taken out one by one by a paper feed roller 11, and guided to the circumferential surface of the drum 1 at the appropriate timing by a pair of registration rollers 12. In the figure, 13 is a turn roller, and 10 is a fixing device for fixing the second toner image onto the recording paper P.

The first developing device 4 is a magnetic one-component developing device containing the first magnetic toner T1, and includes a non-magnetic sleeve 17 that rotates in synchronization with the drum 1, and is disposed inside the sleeve 17. It is composed of a magnet roll 18 that rotates in the same direction as the drum 1, and a doctor blade 19.

The second developing device is also a magnetic one-component developing device containing the second magnetic toner T2, and a non-magnetic sleeve 20.
．． It is composed of a magnet roll 21 and a doctor blade 22, but in order to reduce the influence of the magnetic field generated by this magnet roll 21 on a master image 52 on which a magnetic latent image (described later) is formed, a north pole and a south pole are used. The magnet roll 21 is arranged fixedly, ie, not rotating, so that the middle between the poles coincides with the development position (position close to the drum 1).

The first magnetic toner T1 is mainly composed of a magnetic material having magnetic properties capable of permanent magnetization and a resin binder. Examples of the magnetic material of the first magnetic toner T1 include γ-F e 203 and C.

-γ-F e 203 , barium ferrite, lead ferrite, cobalt ferrite, cobalt ferrite, nickel ferrite, and other iron oxide-based magnetic materials or CrO2 are suitable; In general, the saturation magnetization (or the value of magnetization after applying an external magnetic field or removing the external magnetic field) is as large as 300 emu/g or more. In addition, it is well dispersed in the resin and is chemically stable.
It is desirable to use a material that can easily attack particles in the form of micrometers or less.

The resin for the binder of the first magnetic toner T1 is selected depending on the fixing method, and examples thereof include ethylene-vinyl acetate copolymer, carnauba wax, paraffin wax, polyethylene wax, and amide wax. waxes, ethylene-acrylic acid copolymers, low molecular weight polypropylene, styrene, epoxy, polyester, polyamide, copolymers of acrylic acid or methacrylic acid and long-chain alkyl acrylates, long-chain alkyl methacrylates, styrene and long-chain Copolymers with alkyl acrylates and long-chain alkyl methacrylates are suitable.

Furthermore, in addition to the magnetic material and the binder resin, the first magnetic toner T1 includes an electrical resistance adjusting agent (for example, conductive carbon black, etc.), a wax for adjusting the fixing property, and a charge of the toner. A charge control agent and other additives are added in appropriate amounts depending on the required toner performance. By using it as a toner, a high-definition master image that is faithful to the original can be obtained.

The first magnetic toner T1 can be manufactured using a conventionally well-known pulverization method or spray drying method,
It is used as a powder with a volume average particle size of 5 μm to 50 μm.

Further, it is desirable that the amount of the magnetic material contained in the first magnetic toner T1 be as large as possible, but if the content is too large, there will be a problem in the fixability of the magnetic toner, so there is a certain limit. As a result of studies taken into consideration by the inventors of the present invention, taking into account this problem and manufacturing problems, it was found that a magnetic toner that satisfies practical use can be obtained by containing 30 to 70% by weight.

Further, since the magnetic toner of the present invention is used only for forming a master image, it may be of any color, and there is no restriction on the toner composition depending on the color.

Here, magnetization of magnetic toner will be explained.

In general, magnetization is defined as the magnetic moment per unit volume (CG
In Sm magnetic units, the unit is expressed in remuJ. ), but in the case of magnetic powder or magnetic toner, it is generally used as the magnetic moment per unit weight (unit: remu/g). On the other hand, the residual magnetization of magnetic toner is generally determined using a vibratory capacitance magnetometer that measures the magnetic moment in a DC magnetic field (static magnetic field).

As a result of various studies, the present inventors have found that good magnetic printing characteristics can be obtained if the residual magnetization value of the first magnetic toner T1 is 106 mu/g or more, preferably 15 emu/g or more. The result is as follows.

The second magnetic toner T2 has residual magnetization (or coercive force)
This is a high-resistance magnetic toner containing a magnetic agent with a small resistance, such as Fe, 04, etc.

Next, the operation of the recording apparatus configured as described above will be explained in detail with reference to FIGS. 2 to 11.

The recording process in this recording apparatus is roughly divided into two processes: a master image forming process and a printing process.

First, the master image forming process will be explained.

That is, as shown in FIG. 2, the photoreceptor belt 14 wound around the drum 1 rotates in the direction of the arrow shown in the figure at a speed V1, and at this time, the photoreceptor layer 14a of the photoreceptor belt 14 is uniformly coated by the charger 2. For example, it is negatively charged to -600V. Next, as shown in FIG. 3, one-quadrant exposure is performed by the exposure optical system 3, and the charge on the portion irradiated with the light 3a disappears, forming an electrostatic latent image corresponding to the image on the photosensitive layer 14a. be done. As shown in FIG. 4, the electrostatic latent image thus obtained is formed by the first magnetic toner T1 carried by the interaction between the sleeve 17 and the magnet roll 18 at a position facing the first developing device 4. It is developed with Since the first magnetic toner T1 is a conductive magnetic toner, the latent image charge of the photosensitive layer 14a causes the first magnetic toner T1 to
Electric charges are induced on the photosensitive layer 14a, which is then attracted and adhered to the photosensitive layer 14a by Coulomb force, thereby being developed. In development using the conductive first magnetic toner T1,
Since the toner itself acts as a developing electrode, the electrostatic latent image can be faithfully developed, resulting in an extremely high-definition master image. The electrical resistance, that is, the volume resistivity, of this conductive first magnetic toner T1 is less than 10'2 Ω·mark, preferably 109 Ω.
- It is good if it is 0 or less.

Next, as shown in FIG. 5, the first magnetic toner T1 attracted and adhered to the photosensitive layer 14a is instantaneously melted by the flash lamp of the fixing device 5, and is thermally fixed on the photosensitive layer 14a to form the first magnetic toner T1. A magnetic toner image (master image) 51 is obtained.

The first toner image 51 made of the first magnetic toner T1 formed on the photoreceptor belt 14 in this way is attached to the first magnetic head and the second magnetic toner, as shown in FIGS. 6 and 7. By being sequentially magnetized by the magnetic head 23, a magnetized master image 52, that is, a magnetic latent image is formed. That is, by applying the voltage W1 alternating at a constant cycle to the first magnetic head 9, the first magnetic head 9
Near the front gap g1, a magnetic field alternating at a constant period is generated, and the photoreceptor belt 14 on which the first toner image 51 is formed moves under the first magnetic head 9 at a constant speed V1,
By passing the toner image 51, a certain length g! is deposited on the first toner image 51 in the direction of its surface. A magnetic latent image is formed in which the direction of magnetization is alternately reversed. Next, by applying a voltage W2 that alternates at a constant cycle to the second magnetic head 23, a magnetic field that alternates at a constant cycle is generated in the vicinity of the front face gap g2 of the second magnetic head 23. In the magnetic head, the photoreceptor belt 14 on which the magnetized first toner image is formed moves and passes under the second magnetic head 23 at a constant speed v1, so that it is superimposed on the first toner image. , a magnetic latent image whose magnetization direction is alternately reversed with a constant length g2 is formed in the plane direction.

Here, - within the film, there is a recording pitch, that is, a magnetization transition region M
The distance ρ between is the frequency of the alternating rectangular voltage W (f (Hz)) and the moving speed of the photoreceptor belt 14 (more precisely, the relative speed between the magnetic head 9.23 and the photoreceptor belt 14). If V l (+++m/see), then it is simply expressed as II - Vl/2 f (mm). For example, if f = 1 klz and V 1-60 mm/see, it becomes 11-0.03 mts, that is, 30 μm.

The front gap g1 of the first magnetic head 9 is about 40 μm, so that the entire thickness direction of the first toner image 51 can be easily magnetized. The front gap g2 of the second magnetic head 23 is approximately 10 μm, allowing short recording pitch magnetization.

As described above, the recording pitch N1 (N2) is determined by the moving speed v1 of the photoreceptor belt 14 and the frequency f+ (f2) (ITz) of the alternating voltage Wl (W2), and therefore, "first recording pitch R+>th Recorded pitch of 2,
1) To magnetize to 2J, the frequency f of the alternating voltage applied to the first magnetic head 9 is less than the frequency f2J of the alternating voltage applied to the second magnetic head 23.

Through the master image forming process shown in FIGS. 2 to 7 above, a master image 52 on which a magnetic latent image is formed is obtained. In this master image forming process, the moving speed of the photoreceptor belt 14 is all Vl, and the drum 1 is
This is done sequentially and continuously during rotation.

Next, the printing process will be explained. After the previous master image forming step is performed over one revolution of the drum 1 by one rotation of the drum 1, the drum 1 is rotated at a high speed at a second speed v2. First, as shown in FIG. 8, a master image 52 on which a magnetic latent image has been formed is placed in a position opposite to the second developing device 6 by the magnetic latent image carried by the interaction of the sleeve 20 and the magnet roll 21. The second magnetic toner T2 is attracted and adhered by magnetic attraction, and a second toner image 53 having the same shape as the master image 52 is obtained on the master image 52. Next, this second toner image 53 is uniformly charged to negative polarity by the pre-transfer charger 7, as shown in FIG. The second toner image 53 charged to a negative polarity is then attracted from behind by the transfer charger 8 to the recording paper P charged to a positive polarity, thereby being recorded. paper P
transferred on top. Next, as shown in FIG.
The recording paper P onto which the toner image 53 has been transferred is conveyed to the fixing device 10 and fixed by the fixing device 10 to obtain a duplicate image on the recording paper P, completing the printing process.

Hereinafter, when duplicating the same image, a large number of duplicated images can be obtained at high speed by repeating only the printing steps shown in FIGS. 8 to 11 above. In this printing process, the moving speed of the photoreceptor belt 14 is, for example, 50
0+u/see.

The first developing device 4 and the second developing device 6 of the recording device described above
A first magnetic toner T1 and a second magnetic toner T2 manufactured by the method described below were placed in the container to form an image.

First, a method for manufacturing the first magnetic toner T1 will be described. 36 parts by weight of epoxy resin, 4 parts by weight of carbon black, and 60 parts by weight of barium ferrite are kneaded in a pressure kneader, cooled, and coarsely ground in a hammer mill. Next, it is finely pulverized with a jet mill and classified using an air classifier, with a volume average particle size of 1
A first magnetic toner T1 having a diameter of 9.8 μm was obtained. FIG. 13 shows the hysteresis loop of this first magnetic toner T1. As can be read from FIG. 13, the coercive force of the first magnetic toner T1 is 1750 oersted,
The residual magnetization is approximately 25 emu/g.

Next, a method for manufacturing the second magnetic toner T2 will be described.

54 parts by weight of styrene-acrylic copolymer resin, 40 parts by weight of magnetite, and 6 parts by weight of carbon black were kneaded in a pressure kneader, cooled, and coarsely ground in a hammer mill. Next, it was finely pulverized with a jet mill, and the volume average particle size was 11.2 μm.
A second magnetic toner T2 was obtained. Figure 14 shows this second
The hysteresis loop of the magnetic toner T2 is shown in FIG.

As can be read from FIG. 14, the coercive force of the second magnetic toner T2 is 200 oersted, and the residual magnetization is about 5
It is now emu/H.

Here, among the recording steps mentioned above, the magnetic latent image forming step (
The relationship between the magnetic latent image formed in FIGS. 6 and 7) and the adhesion amount of the second toner T2 will be explained in detail with reference to the drawings. FIG. 16 shows the results of an experiment conducted to investigate the appropriate values of the first recording pitch 11 and the second recording pitch I12 in the stacked magnetization of the present invention. I Qμm as Df12, 20μm,
30 μm, and the adhesion amount (■/cd
) is shown. In the figure, TH indicates the limit of the adhesion amount to obtain a practical image density. As is clear from the figure,
It can be seen that there is a state in which there is no density unevenness and a practical toner adhesion amount is obtained by the overlapping magnetization of the present invention (the volume average particle diameter of the second magnetic toner T2 is 1
1.2 μm). Further, from the figure, it can be seen that the shorter the second recording pitch g2, the wider the appropriate range of the first recording pitch g.

Furthermore, as a result of various studies on the appropriate ranges of the first and second recording pitches 11 and g2, the inventors found that when forming a magnetic latent image on the master image 51, the second magnetic toner T
When the volume average particle diameter of 2 is Dt, 1/2Dt≦p2≦6Dt, and by superimposing magnetization so that the relationships of 2g2≦N and ≦30ρ2 are satisfied, an even and practical concentration can be achieved. It was confirmed that images of .

As explained above, the first toner image 51 formed by the first magnetic toner T1 is transferred between the first magnetic head and the second magnetic toner.
By being doubly magnetized with the magnetic head 23 of the first
As shown in FIG. 5, there is a magnetization reversal section M on the master image 51.
A magnetic latent image is created in which a first magnetic latent image having a first recording pitch IIl with a long distance between them and a second magnetic latent image having a second recording pitch g2 with a short distance between magnetization inversion parts M overlaps. This superimposed magnetic latent image is transferred to a second magnetic toner T.
2, the first magnetic latent image acts to obtain a practical adhesion amount of the second magnetic toner T2, and the second magnetic latent image acts to obtain a practical adhesion amount of the second magnetic toner T2. Acts to adhere. Therefore, with the conventional magnetic latent image having only one type of recording pitch, it was not possible to achieve both the amount of developer (toner) attached and the uniform adhesion of toner, but the magnetic latent image with two types of recording pitch according to the present invention The latent image can achieve both the amount of toner adhesion and the uniform adhesion of toner, and as a result, the reproduced image finally obtained on the recording paper P has high image quality and density.
Moreover, the concentration is uniform and the quality is high.

In the field of magnetic recording (generally magnetic memory), the recording pitch (or recording frequency) is different on the same magnetic recording medium.
It is well known that it is possible to perform overlapping recording (overlapping magnetization) by making the magnets different.

Generally, in the field of magnetic memory, overlapping recording is performed to improve the amount of recorded information, but in the present invention,
Overlapping magnetization is performed to obtain a magnetic latent image with strong magnetic attraction and to form a magnetic latent image that is similar to that in the surface direction of the magnetic recording medium (master image).

To perform overlapping recording (magnetization) with different recording pitches,
It is necessary and important to record the one with the longer recording pitch first. That is, generally, a magnetic head is used as a magnetic latent image forming means, but when magnetizing with a magnetic head,
The depth of magnetization in the thickness direction of the magnetic recording medium (master image) depends on the recording pitch; the longer the recording pitch, the deeper the magnetization, and the shorter the recording pitch, the shallower the magnetization. Therefore,
If the magnet is shallowly magnetized with a short recording pitch and then deeply magnetized with a long recording pitch, the magnetic latent image of the short recording pitch that was previously magnetized will of course be erased and overlapping recording will not be possible.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and a dielectric material may be used instead of a photoreceptor as an image carrier,
The electrostatic latent image may be formed by an electrostatic recording method.

Further, the image exposure means for the photosensitive layer 14a may be configured to irradiate an image-modulated laser beam instead of irradiating the reflected light from the original.

Furthermore, as a method for forming the master image, in addition to electrophotography using magnetic toner, thermal transfer recording using an ink ribbon may be used.

[Effects of the Invention] As described above, according to the present invention, it is possible to obtain images with high density and uniformity equivalent to that of an electrophotographic copying machine, and also to obtain images similar to those of a printing machine using a simple process. It is possible to provide a recording device that can make multiple copies from the same original at high speed.

[Brief explanation of drawings]

1 to 16 show embodiments of the present invention,
FIG. 1 is a schematic configuration diagram of the recording apparatus, FIGS. 2 to 11 are process diagrams for explaining the recording process, FIG. 12 is a schematic sectional view of the magnetic head, and FIG. 13 is a diagram of the first magnetic toner. FIG. 14 is a diagram showing the characteristics of the second magnetic toner, FIG. 15 is a schematic diagram showing the development state of the magnetic latent image, and FIG. 16 is a diagram showing the characteristics of the second magnetic toner.
The figure is a graph showing the recording pitch and the adhesion characteristics of magnetic developer. Figures 17 and 18 are for explaining the conventional recording device, and Figure 17 is a schematic diagram showing the development state of the magnetic latent image. FIG. 18 is a graph showing the recording pitch and the adhesion characteristics of magnetic developer. 2... Charger, 3... Exposure optical system (master image forming means), 4... First developing device (master image forming means), 5... Fixing device (master image forming means),
6... Second developing device (developing means), 7... Pre-transfer charger (transfer means), 8... Transfer charger (transfer means), 9... Magnetic head (first magnetic latent image) forming means), 14...photoreceptor belt (image, carrier), 23...
- Magnetic head (second magnetic latent image forming means), 51...
First toner image (master image), 53... Second toner image, T1... First magnetic toner T2... Second magnetic toner

Claims (1)

[Scope of Claims] An image carrier, a master image forming means for forming a permanently magnetizable master image on the image carrier, and a first predetermined length of the master image formed by the master image forming means. a first magnetic latent image forming means for forming first magnetic latent images with magnetization directions alternately reversed; and a master image on which the first magnetic latent image is formed by the first magnetic latent image forming means. a second length shorter than the first predetermined length;
a second magnetic latent image forming means for overlappingly forming second magnetic latent images whose magnetization directions are alternately reversed over a predetermined length; a developing means for developing the first and second magnetic latent images formed by the above-mentioned magnetic developer with a magnetic developer; and a transfer means for transferring the developer image obtained on the master image by the developing means to a transfer material. A recording device comprising: