JP2725655B2 - Image recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus applied to a printer, a facsimile, a copying machine, etc., and more particularly to an image recording apparatus for recording an image by utilizing a pyroelectric effect.

[0002]

2. Description of the Related Art Conventionally, an electrostatic latent image is formed using a pyroelectric effect, and the formed electrostatic latent image is visualized (developed) with a coloring medium (toner), and then formed on a recording medium. 2. Description of the Related Art There is known an image recording apparatus that records an image by transferring and fixing the image onto a sheet.

An image recording apparatus of this type is disclosed in, for example, Japanese Patent Application Laid-Open No. 56-158350 (hereinafter referred to as "first conventional example").
), The surface of the pyroelectric material is heated using a laser beam or a thermal head to form an electrostatic latent image, and the formed electrostatic latent image is charged with a charged toner. There is a copying apparatus that obtains a copy image of a document by transferring and fixing the image on a recording sheet after development.

As another image recording apparatus of this type, Snelling is disclosed in Japanese Patent Laid-Open No. 5-134506.
No. 5,185,619 (hereinafter referred to as "second conventional example"), the charge generated during heating is efficiently neutralized using charge neutralization means. To form an electrostatic latent image. In the image recording apparatus according to the second conventional example, a heating needle is used as a heating means,
Further, a grounded conductor layer is provided on the surface of the heating needle, and the charge generated during heating is efficiently neutralized by using the conductor layer.

FIG. 3 is a view for explaining an image recording apparatus according to the second conventional example.

Referring to FIG. 3, the image recording apparatus according to the second conventional example has a belt-shaped latent image charge holding medium 43 composed of a pyroelectric layer 44 and a conductive layer 45, A latent image 49 is formed on the latent image charge holding medium 43.

That is, the heating needle 4 in contact with the pyroelectric layer 44
6 is controlled by the controller 48 to selectively heat the surface of the pyroelectric layer 44 according to the image signal. Heating needle 46
Since the grounded conductive layer 47 is formed on the surface of the substrate, the charge generated on the surface of the pyroelectric layer 44 by heating is neutralized by using the conductive layer 47.

Thereafter, when the latent image charge holding medium 43 is cooled, charges of the opposite polarity are generated, and a latent image 49 is formed.
The formed latent image 49 is developed by the developing device 50 to form a toner image 51, and the formed toner image 5
1 is transferred onto the recording medium 52 by the transfer means 53.
In the image recording apparatus according to the second conventional example, the transfer means 53 also uses the pyroelectric effect.

[0009]

Here, when the pyroelectric material is repeatedly used as in the image recording apparatuses according to the first and second conventional examples, the latent image is formed before the latent image is formed. It is necessary to remove the coloring medium attached on the charge holding medium.

[0010] The reason is that if the coloring medium remaining on the latent image charge holding medium is transported as it is, when the next heating is performed, that part becomes thermal resistance, leading to poor printing of white spots, and This is because the coloring medium conveyed to the heating unit adheres to the surface of the heating unit, thereby causing printing defects such as continuous white stripes.

In order to prevent such printing defects, it is common practice to remove the untransferred colored medium remaining on the latent image charge holding medium using an elastic blade, brush or the like.

However, such normal cleaning cannot remove 100% of the untransferred toner. Therefore, there is a problem in that the recording medium is deposited on the heating means during the repetition of recording, and printing failure occurs.

Further, even when the charge neutralizing means is provided separately from the heating means, untransferred toner is deposited on the surface of the charge neutralizing means in the same manner, and the charge neutralizing efficiency is reduced to deteriorate the printing quality. There is a problem.

Accordingly, the present invention has been made in view of the above problems, and periodically removes a coloring medium deposited on the surface of a heating unit or a charge neutralizing unit, thereby obtaining an image such as resolution, contrast, and density uniformity. It is an object of the present invention to provide an image recording apparatus capable of always maintaining a constant quality.

[0015]

In order to achieve the above object, the present invention provides a latent image charge holding medium having a pyroelectric layer and selectively heating the latent image charge holding medium according to an image signal. Heating means for developing, a developing means for visualizing an electrostatic latent image formed on the latent image charge holding medium with a coloring medium, and a transfer means for transferring the visualized image by the developing means onto a recording medium And a cleaning device for removing the coloring medium adhered to the heating device.

According to the present invention, there is provided a heating means for selectively heating a latent image charge holding medium having a pyroelectric layer according to an image signal, and a latent image charge holding medium in contact with the latent image charge holding medium. Charge neutralizing means for removing the electric charge attached on the
An image including developing means for visualizing the electrostatic latent image formed on the latent image charge holding medium with a coloring medium, and transfer means for transferring the image visualized by the developing means onto a recording medium; In a recording apparatus, there is provided an image recording apparatus including a cleaning unit for removing a coloring medium attached to the charge neutralizing unit.

Further, in the image recording apparatus of the present invention, the cleaning means may include a head cleaning means for contacting the heating means or the charge neutralizing means to clean the surface thereof, and the heating means or the charge neutralizing means. Means for releasing the means from contact with the latent image charge holding medium and shifting to a position where it contacts the head cleaning means.

Further, in the image recording apparatus of the present invention, the cleaning means may be a cleaning member provided on a part of the latent image charge holding medium.

In the image recording apparatus of the present invention,
When the cleaning unit removes the coloring medium attached to the heating unit or the charge neutralizing unit, it is preferable that the cleaning unit heats and melts the coloring medium.

According to the image recording apparatus of the present invention, the pyroelectric layer of the latent image charge holding medium is heated in accordance with the image pattern, and the latent image is generated by utilizing the fact that charges are generated in the heated portion by the pyroelectric effect. An image is formed.

Then, the charged coloring medium is brought close to or in contact with the latent image charge holding medium on which the latent image is formed, and the coloring medium is selectively adhered to the surface of the pyroelectric layer to thereby develop the latent image. I do. After the development is completed, the coloring medium adhered on the latent image charge holding medium is transferred and fixed on the recording medium to record a desired image on the recording medium.

On the other hand, the coloring medium remaining on the latent image charge holding medium without being transferred onto the recording medium is scraped off using a cleaner.

However, there are cases where the coloring medium cannot be completely recovered even by using the cleaner. In this case, the remaining coloring medium is transported to the heating means again. When the coloring medium is transported to the heating means, the portion to which the coloring medium adheres is selectively heated based on the print data,
The coloring medium melts and adheres to the heating means.

The fixed coloring medium becomes thermal resistance, and even if print data is present, the latent image charge holding medium cannot be sufficiently heated, resulting in printing defects such as white stripes in the printing result. The attached or fixed coloring medium is appropriately removed by a cleaning means.

In order to easily remove the coloring medium adhered or fixed to the heating means, printing energy is supplied to the heating means at the same time as the cleaning means is operated so that the coloring medium is melted again. .

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[0027]

Embodiment 1 FIG. 1 is a view for explaining an image recording apparatus according to a first embodiment of the present invention.

Referring to FIG. 1, an image recording apparatus according to the present embodiment includes an endless belt-shaped latent image charge holding medium 3, a thermal head 4 as a heating unit for heating the latent image charge holding medium 3, a thermal head 4, A conductive layer 5 provided on the surface of the head 4 as a charge neutralizing means; a developing device 7 serving as a developing means for developing the electrostatic latent image 17 with a charged coloring medium; and a toner image on the surface of the recording paper 11 And a fixing device 15 as a fixing unit.
Cleaner 22 for removing untransferred toner 21
And a thermal head retraction mechanism 26 and a thermal head cleaning mechanism 27 as main components.

The latent image charge holding medium 3 is a belt having an endless film formed of two layers of a pyroelectric layer 1 (thickness of about 30 μm) and a conductive layer 2 (thickness of about 500 Å). The conductor layer 2 is always kept at the ground potential via the conductive roller 20. The materials of the pyroelectric layer 1 and the conductor layer 2 are respectively polyvinylidene fluoride (PVD).
F) and aluminum (Al).

The thermal head 4 is a line type thermal head generally used for thermal transfer recording, and has a small heating element which generates heat by Joule heat of about 83 μm.
The latent image charge holding medium 3 is arranged in a line in the width direction at an m pitch (300 dots / inch). In addition,
The surface of the thermal head 4 is coated with a conductive layer kept at a ground potential to form a conductive layer 5.

A plurality of heating elements provided on the thermal head 4 are controlled by a controller 16 to selectively generate heat in accordance with an image signal, thereby selectively heating the latent image charge holding medium 3. The heating of the latent image charge holding medium 3 is performed such that the latent image charge holding medium 3 is sandwiched between the thermal head 4 and the platen roller 6.

Electric charges are generated by the pyroelectric effect on the surface of the pyroelectric layer 1 of the heated latent image charge holding medium 3, and the generated electric charges are provided in close contact with the surface of the pyroelectric layer 1. The conductive layer 5 of the thermal head 4 is instantaneously neutralized.

After the heating is completed, the latent image charge holding medium 3 is returned to room temperature by natural cooling, thereby forming a latent image 17 of opposite polarity charges. The latent image charge holding medium 3
Can be performed by a forced method such as forced air cooling or heat conduction with a heat sink (cold heat source) in addition to natural cooling.

Latent image 1 formed on latent image charge holding medium 3
7 is developed using the developing device 7. The developing device 7 holds the developer 8 on a sleeve 10 containing a magnet roller 9 and contacts the latent image charge holding medium 3 to selectively apply toner according to the charge distribution on the latent image charge holding medium 3. The latent image is developed by being attached.

After the development is completed, the latent image charge holding medium 3 is overlapped with the recording paper 11 as a recording medium, and the transfer roller 12 to which a voltage is applied is pressed against the back of the recording paper 11 so that the toner image 18 is formed. Electrostatic transfer is performed on the surface of the recording paper 11. In practice, a voltage of about +1 kV was applied to the conductive rubber roller to electrostatically transfer the toner image 18.

The recording paper 11 to which the toner image 18 has been transferred is passed through a fixing device 15 comprising a heat roller 13 and a pressure roller 14, and the toner transferred to the surface of the recording paper 11 is once melted to form a recording paper. 11 is fixed.

After the recording image 19 is transferred to the surface of the recording paper 11 through a series of processes as described above, the latent image charge holding medium 3 is transported toward the thermal head 4, and the process proceeds to the next latent image forming process. .

Before the latent image charge holding medium 3 is conveyed to the thermal head 4, the untransferred toner 21 remaining on the latent image charge holding medium 3 is removed by using a cleaner 22. I do.

When the latent image charge holding medium 3 is formed on the endless belt, if there is a step on the adhesive surface, the toner enters the step and the efficiency of removing the untransferred toner using the cleaner 22. Decrease. Therefore, it is preferable that the latent image charge holding medium 3 is integrally formed using a mold to have a structure having no steps. Further, the same effect can be obtained even if the belt-like pyroelectric body is adhered to the belt-shaped pyroelectric body without causing the stepped portion to be formed after the belt-shaped pyroelectric body is adhered.

Even if the cleaner 22 is used, the untransferred toner 21
Is not completely removed, the untransferred toner 21 is further transported and adheres to the thermal head 4. And
When the thermal head 4 is heated, the attached toner melts and adheres to the surface of the thermal head 4.
In the image recording apparatus according to the present embodiment, since the thermal head 4 is coated with the conductive layer 5, the untransferred toner is actually fixed to the surface of the conductive layer 5.

In the image recording apparatus according to this embodiment, the thermal head 4
Each time printing of one sheet is completed, the pressure contact between the thermal head 4 and the latent image charge holding medium 3 is released.
Is moved to a position where it comes into contact with the thermal head cleaning mechanism 27 so that the toner adhered or fixed to the thermal head 4 is cleaned.

The thermal head cleaning mechanism 27 attaches a polyimide film whose surface roughness has been increased using a chemical to a roller having a rubber hardness of about 50 and an outer diameter of 12 mm, and rotating the roller with a pressing force of 3 kg. The toner fixed on the thermal head 4 was cleaned by setting the number to 100 RPM.

Here, when removing the adhered toner,
When the thermal head 4 is reheated to melt the toner, the toner stuck to the thermal head 4 can be more easily removed.

After the transfer of the toner image 18, the latent image charge may remain on the surface of the pyroelectric layer 1 of the latent image charge holding medium 3, but the remaining latent image charge is grounded. The neutralization can be easily achieved by bringing a conductive brush (not shown) or the like into contact with the surface of the pyroelectric layer 1. Also,
Immediately before the next heating is performed, since the latent image charge holding medium 3 comes into contact with the conductive layer 5, any remaining charges can be neutralized here. That is, it is possible to form a good image free from the influence of the remaining latent image charge (such as generation of a ghost) without providing a special latent image neutralizing unit.

As a result of actually performing image recording using the image recording apparatus having the above-described apparatus configuration, the latent image 1
About 90% of the toner image 18 developed from No. 7 is transferred to the recording paper 11, and the remaining about 10% remains as untransferred toner 21. Further, there was untransferred toner that was not collected by the cleaner 22 but adhered to the latent image charge holding medium 3 until the end, and finally adhered to the thermal head 4. By removing the toner periodically, good image recording could be performed.

Further, it was confirmed that even when image recording was performed continuously, good image recording could be performed, and that sufficient durability and reliability were secured in the entire apparatus.

[0047]

[Embodiment 2] FIG. 2 is a diagram for explaining an image recording apparatus according to a second embodiment of the present invention.

Referring to FIG. 2, the image recording apparatus according to the present embodiment comprises an endless belt-shaped latent image charge holding medium 3, a thermal head 4 as heating means, and a conductive layer 5 as charge neutralizing means. A developing unit 7 as a developing unit, a transfer roller 12 as a transfer unit, a fixing unit 15 as a fixing unit, and a cleaner 2 for removing untransferred toner 21.
2 and a cleaning tape unit 24 as cleaning means for cleaning the thermal head 4 provided on a part of the latent image charge holding medium 3 as main components.

In the image recording apparatus according to this embodiment, as in the case of the first embodiment, heating, neutralization and cooling of the latent image charge holding medium 3, development of the latent image, transfer of toner, and the like are performed. After each process is completed, the untransferred toner is removed by using the cleaner 22.

Even if the cleaner 22 is used, the untransferred toner 21
Is not completely removed, the untransferred toner is further transported and adheres to the thermal head 4. When the thermal head 4 is heated with the toner attached, the attached toner melts and adheres to the surface of the thermal head 4 (actually, the surface of the conductive layer 5).

In the image recording apparatus according to the present embodiment, a cleaning tape portion 24 for cleaning the thermal head 4 is provided on a part of the latent image charge holding medium 3, and the latent image charge holding medium 3 is conveyed to the cleaning tape. When the unit 24 comes to the position of the thermal head 4, the toner adhered or fixed to the thermal head 4 is cleaned by the cleaning tape unit 4.

When removing the adhered toner,
As in the case of the first embodiment, the thermal head 4
Is reheated to melt the toner, it is possible to remove the adhered toner more easily.

The cleaning tape portion 24 is preferably of a structure integrally formed with the latent image charge holding medium 3 in which the surface roughness of a part of the latent image charge holding medium 3 is increased by using a chemical. The problem that untransferred toner accumulates on the step of the joint between the layer 1 and the cleaning tape portion 24 can be avoided.

Incidentally, in order to form the cleaning tape section 24, the latent image charge holding medium 3 and a cleaning tape of another material may be joined. However, in this case, it is preferable that the surface is sufficiently finished so that the untransferred toner does not accumulate at the joining portion, and the belt is formed as an endless belt having no step.

Further, in the image recording apparatus according to the present embodiment, the thermal head 4 and the platen roller 6 are not pressed and released as in the first embodiment. It is possible to suppress the occurrence of color misregistration due to mechanical misalignment, and to obtain better print quality.

Although some embodiments of the present invention have been described above, the present invention is not limited to these embodiments, but includes various embodiments according to the principle of the present invention.

For example, in the image recording apparatuses according to the first and second embodiments, the thermal head 4 is coated with the conductive layer 5, but the conductive layer 5 is provided separately from the thermal head 4. Can also. In this case,
In addition to cleaning the surface of the thermal head 4, the conductive layer 5 provided at another position is also cleaned by the method described in the first and second embodiments. It is preferable to suppress the decrease in the charge neutralization efficiency due to the above and prevent the deterioration of the print quality.

In the image recording apparatuses according to the first and second embodiments, the thermal head 4 is used to form a latent image. However, the latent image is formed using a laser beam or a heating needle. This can be applied in the same way.

[0059]

As described above, according to the image recording apparatus of the present invention, the coloring medium deposited on the surface of the heating means or the charge neutralizing means can be periodically removed, so that the latent image charge holding medium and the latent image charge holding medium can be removed. It is possible to secure stable and uniform contact with the heating means or the charge neutralizing means, to form a good latent image, and to perform recording with excellent image quality.

According to the image recording apparatus of the present invention, a cleaning tape portion is provided on a part of the latent image charge holding medium,
Because the colored medium can be removed without changing the positional relationship between the latent image charge holding medium and the heating unit or the charge neutralizing unit, the occurrence of positional shift of the latent image is suppressed, and multicolor printing is performed. Also, stable recording with excellent image quality can be performed without causing a problem such as color misregistration.

Further, according to the image recording apparatus of the present invention,
In order to remove the coloring medium deposited on the heating means or the charge neutralizing means after melting the fixed coloring medium, the removal of the coloring medium can be performed more efficiently, and the latent image charge holding medium and the heating means or It is possible to secure stable and uniform contact with the charge neutralizing means, form a good latent image, and perform recording with excellent image quality.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an image recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining an image recording apparatus according to a second embodiment of the present invention.

FIG. 3 is a diagram for explaining an image recording apparatus according to a second conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pyroelectric layer 2 Conductive layer 3 Latent image charge holding medium 4 Thermal head 5 Conductive layer 6 Platen roller 7 Developing device 8 Developer 9 Magnet roller 10 Sleeve 11 Recording paper 12 Transfer roller 13 Heat roller 14 Pressure roller 15 Fixing device 16 Controller 17 Latent Image 18 Toner Image 19 Recorded Image 20 Conductive Roller 21 Untransferred Toner 22 Cleaner 23 Collected Toner 24 Cleaning Tape 26 Thermal Head Retraction Mechanism 27 Thermal Head Cleaning Mechanism

Claims (6)

(57) [Claims] A heating means for contacting the latent image charge holding medium having a pyroelectric layer and selectively heating the latent image charge holding medium in accordance with an image signal; and a heating means formed on the latent image charge holding medium. A developing unit for visualizing the electrostatic latent image with a colored medium, and a transfer unit for transferring the image visualized by the developing unit onto a recording medium. An image recording apparatus comprising a cleaning unit for removing a coloring medium. 2. A heating means for selectively heating a latent image charge holding medium having a pyroelectric layer in accordance with an image signal; and a heating means for contacting the latent image charge holding medium and adhering to the latent image charge holding medium. Charge neutralizing means for removing electric charges, developing means for visualizing an electrostatic latent image formed on the latent image charge holding medium with a coloring medium, and a recording medium for displaying the image visualized by the developing means. An image recording apparatus comprising: a transfer unit configured to transfer an image on a charge medium; and a cleaning unit configured to remove a coloring medium attached to the charge neutralizing unit. 3. An image recording apparatus according to claim 2, wherein said charge neutralizing means is attached to said heating means. 4. A cleaning device comprising: a head cleaning unit that abuts on the heating unit or the charge neutralizing unit to clean a surface thereof; and a unit that transfers the heating unit or the charge neutralizing unit to the latent image charge holding medium. The image recording apparatus according to any one of claims 1 to 3, further comprising: a unit configured to release from the contact and move to a position where the head cleaning unit contacts the head cleaning unit. 5. An image recording apparatus according to claim 1, wherein said cleaning means is a cleaning member provided on a part of said latent image charge holding medium. 6. The apparatus according to claim 1, wherein said cleaning means heats and melts the coloring medium when removing the coloring medium adhering to said heating means or said charge neutralizing means. 6. The image recording apparatus according to any one of 5.