JPS6054862A - Magnetic printer - Google Patents

Abstract

PURPOSE:To prevent the occurrence of copying failure by a method in which a high-heat conductive film is interposed between a magnetic latent image carrier and a thermal head, residual developer is removed out, and the high-heat conductive film is preheated to a preset temperature. CONSTITUTION:A high-heat conductive film 19 interposed between a magnetic latent image carrier 1 and a thermal head 10 is engaged between a supply roll 17 and a winding roll 16 and preheated to a predetermined temperature by heaters 18A and 18B. The heat to be generated according to image signals by the heating elements of the thermal head 10 is transmitted through the film 19 to the carrier 1 and applied. The temperature of the film 19 is thus raised to more than the lowest temperature necessary for occurring good thermal residual magnetizing phenomenon, and the condition is kept for long periods of time. The adherence of residual developer 12 on the carrier 1 to the thermal head 10 can thus be prevented, sufficient heat energy can be supplied to the carrier 1, and high-quality hard copy can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application) The present invention relates to magnetic printers, and in particular, the invention relates to a method for preventing developer remaining on a magnetic latent image carrier from reaching a thermal head (IW). This relates to a magnetic printer equipped with means for effectively stopping μj.

A magnetic printer forms a magnetic latent image on a magnetic latent image carrier,
The magnetic latent image is visualized using a magnetic developer, and the visualized image is further transferred to plain paper or the like to obtain a hard copy, and has recently been attracting attention as a printer.

(Prior Art) FIG. 1 is a schematic configuration diagram of a conventionally known general magnetic printer.

The magnetic latent image carrier 1 has a magnet 7 for both unidirectional magnetization and demagnetization.
The magnet is uniformly magnetized in one direction. The magnetic latent image carrier 1 is, for example, a tape formed by coating a Mylar base with a thickness of 75 μm with Cr0z powder as a magnetic layer.

The magnetic latent image carrier 1 is heated pixel by pixel according to an image signal by a thermal head 10 that is in circumferential contact with the magnetic latent image carrier 1. In addition, in B), a bias magnetic field in the opposite direction to the unidirectional magnetization is applied to the heated portion by a bias magnetic field generating magnetic rectifier 11.

As a result, a magnetic latent image corresponding to the image signal is formed on the magnetic latent image carrier 1 by the thermal residual magnetization phenomenon.

The magnetic latent image formed in this way is processed by the developing device 2.
The image is visualized using a developer that controls magnetism (for example, -component non-conductive magnetic 1-ner: specific resistance 1r'c10''0 cm).

The visualized developer can be used to generate a negative electric current, for example, using a Brittransf 11 Ni10 mill 3. I can get it. 1 When the developed image on the magnetic latent image carrier 1 reaches below the transfer roll 4, the plain paper 6 fed from the paper tray 5 joins, and the magnetic latent image carrier 1 and the lfH paper 6 are evenly distributed. Proceed at speed.

Since a bias voltage is applied to the transfer roll 4 to attract the charge of the developer, the developer or developed image on the magnetic latent image carrier 1 is transferred onto the plain paper 6 by the transfer roll 4. be done. The plain paper 6 to which the developer has been transferred then passes through a fixing device (not shown) and becomes a hard copy.

On the other hand, the magnetic latent image carrier 1 which has completed the transfer is demagnetized by the magnet 7 for unidirectional magnetization and demagnetization, and is uniformly magnetized. After the transfer, the developer remaining on the magnetic latent image carrier 14 is neutralized by a pre-clean step 8, and then removed by a proper cleaning device 9.

You can make 1q of various hard copies without repeating the above process.

In the magnetic printer shown in FIG. Equipped with the most reliable and proven vacuum comb/fur brush, it was evaluated as a cleaning device.

In this case, (1) If an 0r02 layer with a thickness of 5 μm is used as the magnetic layer of the magnetic latent image carrier 1, the coercivity of 1 cl is approximately 500 μm.
Ørsted, :1 Nicoli-1:,! - [c is 126
°C, (2+) A magnet 7 capable of generating a magnetic field of about 700 Oe in the magnetic layer (CI'02) of the magnetic latent image carrier 1 is used as the magnet 7 for both unidirectional magnetization and demagnetization. (3) As the '1 normal head 1o, the humidity of the heating element itself is 350°C, and the temperature of the magnetic layer of the magnetic latent image carrier 1 is approximately 200'C (more than one point Tc on the key). (/I) Also, as the bias magnet W generating magnet 11, a magnetic field capable of generating a magnetic field of about 501-Rusted is used in the magnetic layer of the magnetic latent image carrier 1. I used ij.

In the magnetic printer configured as described above, the residual developer after cleaning with a vacuum fur brush is approximately 0.002 according to visual density measurements, and it has been extremely difficult to reduce the residual developer to less than this.

By the way, the explanation regarding FIG. In the magnetic printer, as shown in FIG. If residual developer adheres to the thermal head 10, it will adhere to and accumulate on the heating element portion of the thermal head 10.

Then, due to the influence of the accumulated developer, the heat of the heating element of the thermal head is not sufficiently transmitted to the magnetic latent image carrier 1.

For this reason, the thermal residual magnetization phenomenon of the magnetic latent image carrier 1 does not occur in accordance with the columns, which causes a problem in the formation of the magnetic latent image. As a result, there is a drawback that the copy image quality eventually deteriorates or it becomes impossible to copy.

In addition, as a result of repeating the copying process of forming a latent image → developing → transferring → demagnetizing → cleaning with a magnetic printer configured as shown in FIG. It was confirmed that J stains caused problems in forming a magnetic latent image.

In order to improve the above-mentioned drawbacks, the present inventors proposed a magnetic blink having an IC high thermal conductivity film interposed between the thermal head and the magnetic latent image carrier.

FIG. 2 is a schematic side view showing 48 configurations of the magnetic printer according to the above proposal. In this figure, the same reference numerals as in FIG. 1 represent the same or the same parts.

In this configuration example, a highly thermally conductive film 19 is interposed between the magnetic latent 4 + Jfl holder "1" and the thermal head 10 which is in sliding contact with this. is fed out from the supply roll 17 and wound onto the take-up roll 16.

During normal recording operation, heat from the thermal head 10 is transferred to the magnetic latent image carrier 1 through the highly thermally conductive film 19.
propagate to. Therefore, in a manner similar to the prior art process described above with reference to FIG. be able to.

As can be easily understood from FIG. 2, the developer 12 remaining on the magnetic latent image carrier 1 after the transfer and cleaning by the cleaning means 9 is removed by
At the recording site directly below d, a highly thermally conductive film 19
and is removed by (=I[).

As is clear, in this configuration, the thermal head 10 does not come into direct contact with the surface of the magnetic latent image carrier 1 (the latent image forming surface 411 or the surface where the developer is deposited).
The residual developer 12 (=I1) from adhering to the circle I/dot 10 is completely prevented.

In this case, since the high thermal conductivity film 19 is wound up by the winding roll 16 in the direction shown by the arrow 15 in FIG.
A new surface is always interposed between the υ-maru head 10 and the magnetic latent image carrier 1.

Therefore, the contact surface of the thermally conductive film 19 with the thermal head 10 can always be kept in an initial clean state, and the residual developer 12 can be prevented from accumulating on the heating element part of the thermal head 10. It can be completely prevented.

Furthermore, the winding speed of the highly thermally conductive film 19 can be set arbitrarily, and the winding direction can also be reversed from that shown in the drawings (naturally).

Next, since the highly thermally conductive film 19 is rubbed against the magnetic layer on the linear head 10 and the magnetic latent image carrier 1, it must be highly resistant to rubbing. As such a film, for example, a polymer film such as polyimide is suitable.

Furthermore, the single high thermal conductivity film shown in FIG. It must be such that the heat from the thermal head 10 is instantaneously propagated within the highly thermally conductive film 19 and transmitted to the magnetic latent image carrier 1.

For this purpose, it is preferable to use a polymer film in which fine particles of non-magnetic stone (for example, aluminum) having high thermal conductivity are dispersed.

Furthermore, the high thermal conductivity film 1119 has high thermal conductivity in the thickness direction of the film, but has poor heat conductivity in the plane direction of the film. It is preferable that the film is such that heat is transmitted to the magnetic latent image carrier 1 only in this area, and the heat spreads little in the plane direction.

For this purpose, for example, non-magnetic materials with high thermal conductivity (
It is desirable to use, as the high thermal conductivity film 19, T1-shaped fine particles of aluminum (for example, aluminum, etc.) dispersed in the polymer film, the acicular direction of which is perpendicular to the film surface.

Note that in the above configuration, the highly thermally conductive film 19
The residual developer 12 adhering to the can also be collected and reused. Further, in the case of FIG. 2, the cleaning means 9 can be simplified or omitted.

However, if the inventors' experiments show J5, the magnetic printer shown in FIG.
It has been found that the thermal residual magnetization phenomenon no longer occurs as per the step-cutting process, which may impede the formation of a magnetic latent image.

After various studies on the causes of this, we found that although the film 19 is highly thermally conductive, it does not faithfully propagate the heat generation profile of 1:10 in thermal head 10 due to the thermal resistance of the thermally conductive film 19.
It was confirmed that this is because the heat of the heating element was not sufficiently transferred to the magnetic latent image carrier 1.

This point will be explained in detail below with reference to FIG.

FIG. 3 is a diagram showing the rise characteristics of the temperature of the heating element and the temperature of the magnetic latent image carrier 1 when a predetermined heating current is supplied to the thermal head 10.

In the figure, the horizontal axis represents time and the vertical axis represents temperature.

In addition, in FIG. 3, the curve △ represents the depletion of the heating element itself when the thermal head 10 is not brought into contact with the magnetic latent image carrier 1 or one highly thermally conductive film, and the curve B represents the depletion of the thermal head 10 as a magnetic WI image. The curve C represents the temperature of the heating element itself when it is in contact with the highly thermally conductive film 19 for printing, and the curve C represents the scrap in the state shown in FIG. In other words, the temperature of the magnetic latent image 77J is the same as that shown in FIG. 1, respectively.

Note that the temperature is the minimum temperature required to produce a good thermal remanent magnetization phenomenon.

As is clear from this figure, even if a pulsed current is applied to the heating element between 114th time t1 and t2, the temperature of each part will rise by 2μ2 instantaneously, but with a certain time constant. Rise. In addition, the temperature of the magnetic latent image carrier 1 at this time has a lower rate of increase than that of the heating element due to the heat exchange efficiency a3J, thermal resistance, etc., and the peak rate of temperature increase is lower. It will be suppressed.

As is clear from a comparison with curves C and D in FIG. 3, this phenomenon occurs when a highly thermally conductive film is interposed between the thermal head and the magnetic latent image carrier. , becomes even more impressive.

For this purpose, as illustrated by the curved line in FIG. 3, in this case, the magnetic latent image carrier is This is done because the temperature of step 1 may not rise.

In such a case, a good magnetic latent image is not formed on the magnetic latent image carrier 1, and a vacancy occurs in which a good copy cannot be obtained.

(Purpose) The present invention has been made to eliminate the above-mentioned drawbacks, and its purpose is to prevent the residual developer on the magnetic latent image carrier from adhering to the thermal head after transfer. To provide a magnetic printer which can completely prevent the occurrence of C copy defects due to a decrease in the upper temperature limit of a magnetic latent image carrier during printing. It's about doing.

(Summary) In order to achieve the above-mentioned object, the present invention interposes a highly thermally conductive film between a magnetic latent image carrier and a normal head that is in sliding contact with the magnetic latent image carrier. The present invention is characterized in that the residual developer is attached to and removed from the highly thermally conductive film, and the highly thermally conductive film is preheated to a predetermined temperature.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 4 is an enlarged side view showing essential parts of an embodiment of the present invention. In Figure 4, the same symbols as in Figures 1 and 2 are
The same or the same lodging area is being damaged.

The supply roll 17 and take-up roll 16 of the highly thermally conductive film 19 have built-in heaters 18Δ and 18B, respectively. The highly thermally conductive film 19 is always preheated to a predetermined temperature by these heaters.

Therefore, in the heating element of the thermal head 10,
The heat generated in response to the image signal is transferred to and applied to the magnetic latent image carrier 1 through the highly thermally conductive film 19 that is preheated as described in 1) u.

In the embodiment shown in FIG. 4, the temperature E characteristic of the magnetic latent image carrier 1 when a predetermined heating current is supplied to the thermal head 10 is shown by a curve E in FIG.

Note that the curves in this figure are the same as the curves shown in FIG. 3, and are reproduced for convenience of comparison.

As described above, according to this embodiment, the highly thermally conductive film 19 is always preheated to a preset temperature. Therefore, as is clear from FIG. 5, when the pulsed heating current starts to be supplied to the heating element at time t1, the temperature of the highly thermally conductive film 19 reaches a good level after a very short time d. ν? above the minimum temperature T required to produce a thermal remanent magnetization phenomenon. and hold that state for a sufficiently long time.

Therefore, if J is used in this embodiment, there will be no shortage of elevation of the magnetic latent image carrier 1 during recording, and the height will be the same as when the high thermal conductivity film 19 is not interposed. You can be sure of getting a quality copy.

Note that this embodiment can be modified and implemented in a number of ways.

(1) A heater can be installed only on either the take-up roll 76 or the f-feed n-luer 7.

(2) Indicated by the dotted line 18C in FIG. 4, the upstream side and An independent highly thermally conductive film heating means is provided on at least one of the downstream sides).

(3) If the highly thermally conductive film 19 itself becomes an electrical resistor due to the dispersion of fine aluminum particles, etc., the portion of the highly thermally conductive film 19 that comes into contact with the thermal head 10I5 and the magnetic latent image carrier 1 is heated from the outside. By supplying current, it generates heat 11 itself.

(Effects) As is clear from the above description, according to the present invention, the following effects are achieved.

(1) Since the residual developer 12 on the magnetic latent image carrier 1 will no longer adhere to the legal head 10, the residual magnetization phenomenon of the magnetic latent image carrier 1 will occur in the settings B1 and J5 and will last for a long time. A good 9f copy can be obtained over the entire range.

(21 Since the highly thermally conductive film 19 is preheated, sufficient thermal energy to cause the thermal residual magnetization phenomenon is supplied to the magnetic latent image carrier 1, and the desired magnetic latent image is formed well.
and can be formed reliably.

This ensures a high quality hard copy.

(3) Since the v-run head 10 does not get dirty, maintenance is simplified.

(4) If the residual developer 12 adhering to the highly thermally conductive film 19 is collected and reused, the efficiency of developer utilization is improved.

[Brief explanation of drawings]

Figure 1 is a side view showing the schematic configuration of a conventional magnetic printer;
Fig. 2 is a side view showing a schematic configuration of an example of a magnetic printer proposed by the present inventors; The figure is an enlarged side view of the main parts of an embodiment of the present invention, and FIG. 5 is a diagram showing the temperature rise characteristics of each part in the configuration of FIG. 4. 1... Magnetism Latent image carrier, 2... Developing device, 3... Pre-1 to Lancer corotron, 4... Transfer roll,
5...Paper tray, 6...Plain paper, 7...Unidirectional magnetization/demagnetization magnet, 8...Pre-clean
Corotron, 9...Cleaning means, 10...Mall head, 11...Magnet for generating bias magnetic field, 1
2...Residual developer, 16...Take-up roll, 17
... Supply roll, 18A, 18B... Heater,
18C... Heating means 19... Highly thermally conductive film Patent attorney Michito Hiraki 1 other name Fang 1 figure 9 A' 2 figure Fang 3 figure 5 figure

Claims (1)

[Scope of Claims] (1) A magnetic latent image carrier that travels in one direction along a predetermined route, and a magnetic latent image carrier that is arranged along the predetermined route and moves the magnetic latent image carrier uniformly in the predetermined direction. a magnet device that magnetizes; a thermal head device that heats the magnetic latent image carrier pixel by pixel according to an image signal and forms a magnetic latent image on the magnetic latent image carrier by a thermal residual magnetization phenomenon; , a magnetic printer comprising: a developing device for applying a developer to the magnetic latent image to visualize the magnetic latent image; and means for transferring the visualized developer image onto plain paper; heating the highly thermally conductive film interposed between the permanent head and the magnetic latent image carrier; and heating the highly thermally conductive film interposed between the thermal head and the magnetic latent image carrier. A magnetic printer characterized by a good means. (2) the highly thermally conductive film is fed out from one side;
Patent (3) characterized in that the high thermal conductive film is a polymer film in which fine particles of a non-magnetic material having high thermal conductivity are dispersed. A magnetic printer according to claim 1 or 2. (4) The high thermal conductivity film is made by adding acicular fine particles of a non-magnetic material having high thermal conductivity to a polymer film.
So that the polygonal direction becomes the center of gravity on the film surface,
A magnetic printer according to claim 1, page 1J; or claim 2, wherein the magnetic printer is a fishing machine.