JPH0789252B2 - Image forming device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer.

2. Description of the Related Art As conventional image forming apparatuses such as copying machines and printers,
For example, an apparatus using an electrophotographic system disclosed in Japanese Patent Laid-Open No. 214175/1983 is generally used.

FIG. 6 is a schematic sectional view showing the structure of this conventional electrophotographic image forming apparatus. 101 is a photosensitive drum which is a latent image carrier, 102 is a uniform electrostatic charge on the photosensitive drum 101. A corona charger for charging, 103 is a charged photosensitive drum 1
Laser forming a latent image by exposure according to the image signal on 01, an optical system such as an LED array, 104 by the developer carrying member 104 _a, soluble with a developer a latent image formed on the photosensitive drum 101 A developing device that visualizes the image, 105 is a transfer charger that transfers the visible image on the photosensitive drum 101 to the recording medium 106, and 107 is a developer that remains on the photosensitive drum 101 after being transferred to the recording medium 106. A waste toner processing cleaner 108 is a fixing device for fixing the visible image formed by the transferred developer onto the recording medium 106.

Or more in the conventional image forming apparatus configured as described above, a latent image is formed by a charger 102 and an optical system 103 on the photosensitive drum 101, the photosensitive drum by the developer carrying member 104 _a of the developing device 104 The latent image on 101 is visualized and is transferred to the recording medium 106 by the transfer device 105. However, since the developer on the photosensitive drum 101 is not 100% transferred to the recording medium 106, the remaining developer is cleaned by the cleaner 107 before the latent image is formed by the optical system at the next recording. On the other hand, the image transferred to the recording medium 106 is generally heat-fixed by the fixing device 108.
Further, the photosensitive drum 101 is charged toward the next recording, and the process proceeds to image exposure by the optical system.

The invention is as you try to challenge, however the resolution configuration, generally to the developer carrying member 104 _a of the developing device, since the exposed than the portion developing device 104 which is opposed to at least the photosensitive drum surface, standby or Vibration or shock when not in use, or when the developer on the developer carrier is spilled or scattered when the developer 104 is replaced, etc., the inside of the device or the installation location becomes dirty, and it is necessary to pay attention to handling. Had challenges.

In view of the above points, the present invention has an object to provide an image forming apparatus which has good maintainability and handleability without spilling or scattering of the developer during standby or non-use, or during replacement of the developing device. To do.

Means for Solving the Problems The first aspect of the present invention is a development in which at least a developer carrying member, a developer and a layer forming means for uniformly forming a thin layer of the developer on the developer carrying member are integrated. A unit, a recording unit that directly forms a latent image on the developer on the developer carrier, a transfer unit that transfers the latent image-formed developer on the developer carrier to a recording medium, and the developer carrier And an image forming apparatus having voltage applying means for returning the developer on the developer carrier into the developing unit between the layer forming means and the layer forming means.

A second aspect of the present invention integrates at least a developer carrier corresponding to a plurality of color developers and a layer forming means for uniformly forming a thin layer of the developer on the developer carrier. A developing unit, recording means for forming a latent image directly on the developer on the developer carrier, transfer means for transferring the latent image-formed developer on the developer carrier to a recording medium, and the developing unit. A color image forming apparatus having a voltage applying unit for returning the developer on the developer carrier into the developing unit between the agent carrier and the layer forming unit.

A third aspect of the present invention is to provide a latent image forming means around the latent image carrier, at least a developer carrier for developing the latent image, and a thin layer of the developer uniformly charged on the developer carrier. A developing unit that is integrated with a layer forming unit that forms a layer, a transfer unit that transfers the developer to a recording medium, a cleaning unit that cleans the developer on the latent image carrier, the developer carrier, and the layer. The image forming apparatus includes a voltage applying unit that returns the developer on the developer carrier into the developing unit between the forming units.

Action The present invention has the above-described structure, and after recording, an electric field is applied between the developer carrying member and the layer forming unit by the voltage applying unit,
By returning the developer on the developer carrying member to the layer forming means side, that is, in the developing unit, and leaving at least the portion of the developer carrying member exposed from the developing unit, the developer is on standby or not in use. It is possible to prevent the developer from spilling or scattering during vibration or shock at the time, or when the developing device is replaced, and improve the maintainability and handleability.

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

FIG. 1 is a block diagram of the image forming apparatus in the first embodiment of the present invention. 2 and 3 are partially enlarged views thereof.

In the figure, 1 is a developer carrier, 2 is a developer, and 3 is a layer forming means, which comprises supply members 3 _a and 3 _b and a layer forming member 3 _c . Four
Is at least the developer carrier 1, the developer 2, and the layer forming means 3
Is an integrated developing unit. 11 is a voltage applying means for applying an electric field between the developer carrying member 1 supplying member 3 _a. A latent image forming means 5 is composed of an ion generating section _5a and an ion control section _5b . 6 is a transfer means, 7 is a recording medium,
Reference numeral 8 is a paper feeding means, and 9 is a fixing means.

The operation of the image forming apparatus of this embodiment configured as described above will be described below.

In the developing unit 4, the developer 2 is supplied by the layer forming means 3 onto the developer carrying member 1 to form a thin layer. Supply member
3 _b agitates and supplies the developer 2 in the developing unit 4, and 3 _a supplies the developer 2 to the developer carrier 1 in a fixed amount while charging the developer 2. The supplied developer 2 is successively and uniformly formed into a thin layer by the layer forming member 3 _c on the developer carrying member 1 rotating in the direction of the arrow in the figure, and is evenly charged by friction with the layer forming means 3. To be done.

The developer 2 uniformly charged and uniformly thinned is the latent image forming means 5.
As a result, in accordance with the image signal, the layer forming means 3 is charged with a polarity opposite to the polarity charged. For example, the ion generator 5 _a generates ions having a polarity opposite to the charge polarity in the layer forming means 3, and the ion controller 5 _b irradiates the ions according to an image signal by the electric field, so that the developer 2 itself is irradiated. Directly charged latent images are sequentially formed. As the latent image forming unit 5, an image forming unit including an electrostatic head and a discharge head by ionization by air discharge or the like is preferable, and it is further preferable that the latent image forming unit 5 is not in contact with the developer carrying member 1.

The developer 2 on which the latent image is formed is reversely charged at the transfer position onto the recording medium 7 conveyed in the direction of the arrow from the paper feeding means 8 composed of a paper feeding roller and a cassette at the transfer position. polarity,
That is, only the developer 2 latently imaged by the transfer means 6 such as a corona transfer device having the same polarity as the charging by the layer forming means 3 is transferred.

The recording medium 7 completes a recorded image through fixing means 9 for fixing the transferred visible image of the developer 2. On the other hand, the developer carrying member 1 after the transfer enters the developing unit 4, and the developer 2 including the portion taken by the transfer is uniformly charged and thinned again on the developer carrying member 1 by the supplying means 3. And proceed to the next record.

And after the end of one recording ends or the image signal also rotate the developer carrying member 1, a developer carrying member 1 and by a potential difference developer on carrier 1 by the voltage application means 11 between the supply member 3 _a By returning the developer 2 to the supply member 3 _a side, that is, inside the developing unit 4, the developer 2 on the developer carrier 1 is removed or the amount of adhesion is reduced. Further, the portion where the developer is removed or the adhesion amount is reduced may be at least the portion exposed from the developing unit 4.

As described above, since the developer 2 is removed from the developer carrier 1 after recording, the developer carrier 1 is vibrated or shocked in the standby state or the unused state, or when the developing unit 4 is replaced. Therefore, the developer 2 is prevented from spilling or scattering in the apparatus or the installation place.

In this embodiment, a non-magnetic one-component toner is used as the developer 2. Layer forming means 3 was composed by the supply member 3 _a and soft elastic body blade by the conductive brush roller planted conductive thin fibers and the layer forming member 3 _c. At this time, the toner is supplied to the developer carrying member 1 by making the brush roller 3 _a of the supply member overlap with the developer carrying member 1 (about 0.5 mm),
The thin layer formed of the toner to the developer carrying member 1 is performed by pressing a soft elastic blade 3 _c of the layer forming member to the developer carrying member 1. At the same time, in this process, the toner is charged with a charge due to friction. The polarity of this charge depends on the material such as the developer and the blade. FIG. 2 is a state diagram of the latent image forming portion, showing the charged state of the developer 2. For example, a non-magnetic one-component toner having a charge amount of 1 to 5 μC / g and an average particle diameter of 10 μm, which is made of a conductive developer carrier 1 made of stainless steel and a charge control agent such as a binder of styrene-acrylic resin, a pigment, and silica. Resistivity 10 containing carbon in rayon
^When a conductive brush roller of ⁵ to 10 ⁸ Ω · cm and a urethane rubber blade that presses the developer carrier 1 at a linear pressure of about 40 g / cm are used, the developer 2 on the developer carrier 1 is 2 to 2. The layer was uniformly thinned into three layers, and was uniformly + charged (2 _a ), and the surface potential was about + 20V. And this developer 2
To, for example, -5KV generated by the corona discharger 5 _a was applied to - ion stream is irradiated in accordance with the image signal of ion flow control electrodes 5 _b has portions only developer 2 is irradiation - are charged to the latent The image (2 _b ) is formed. The surface potential at this time is -70
It was about V. And at the transfer position-a charged latent image (2
_b ) is applied to the corona transfer device 6 through the recording medium 7, for example, by applying a voltage of +5 KV having a polarity opposite to the charging polarity of the latent image, only the latent image portion (2 _b ) of the developer 2 is recorded on the recording medium 7. Transcribed. The transferred image is fixed to the recording medium 7 by the fixing device 9 of the heat roller to form a recorded image. Further, the developer 2 on the developer carrying member 1 is uniformly charged and has a uniform thin layer on the developer carrying member 1 again by the layer forming means 3 including the replenishment of the developer 2 transferred in the developer unit 4. It is converted to the next record. To remove the developer 2 on the developer carrier 1, the developer carrier 1 is rotated even after the recording of one sheet or a continuous number of sheets, and the voltage applying means 11 is provided between the developer carrier 1 and the supply member 3 _a . - voltage (preferably -50 to-100 V) developer 2 on the developer carrying member 1 and applying a is returned to the developing unit 4 by the supply member 3 _a, a developer 2 of the developer carrying member 1 is almost Was removed.

Further, in the next recording, the developer carrier 1 is rotated prior to the start of recording, so that the developer 2 is supplied onto the developer carrier 1 as in the normal recording state.

As described above, according to this embodiment, after the recording, the developer 2 is formed on the portion of the developer carrier 1 exposed from the developing unit 4.
Therefore, there is no spillage or scattering of the developer from the developer carrier 1 into the apparatus due to vibration or shock in the standby state or the non-use state. Further, spillage at the time of exchanging the developing unit such as replenishment of developer and switching to color is eliminated, and maintainability and handleability are improved.

Further, in the developing unit 4, the developer 2 is supplied onto the developer carrying member 1 by the layer forming means 3 to be uniformly charged and uniformly thinned to form a charged latent image on the developer 2 itself according to an image signal. Thus, latent image formation, development, and transfer can be performed on the developer carrier 1, and the photosensitive drum, which is a conventional latent image carrier, becomes unnecessary. Further, since a latent image is directly formed on the developer 2 and transferred, a cleaner and waste toner treatment are unnecessary. The portion lost by the transfer is replenished in the developing unit 4 by the layer forming means 3 and a thin layer is formed again on the developer carrying member 1.

Therefore, the developing unit 4 alone does not require a photosensitive drum or a cleaner. Further, the developing unit 4, the latent image forming means 5, and the transfer means 6 become an extremely simple process and can be made small and thin. Further, where the user operates including the replenishment of the developer 2, only the developing unit 4 is replaced, and the maintainability and handleability are extremely easy.

Further, as the device, the movable part is only the developer carrying member 1, and the reliability is improved. Further, the developing unit 4 and the transfer unit 6, the developing unit 4 and the latent image forming unit 5, the developing unit 4, the latent image forming unit 5 and the transfer unit 6 and the like can be integrated, and the reliability and operability are excellent. It is possible to provide the image forming apparatus.

FIG. 4 is a block diagram of a color image forming apparatus according to the second embodiment of the present invention. Since the structure and operation corresponding to each color are the same as those in the first embodiment, the description thereof will be omitted. 10Y, 10M and 10C are yellow, magenta and cyan developer carrying members, 40
Y, 40M and 40C are yellow, magenta and cyan developing units, 50Y, 50M and 50C are yellow, magenta and cyan latent image forming means, and 60Y, 60M and 60C are yellow, magenta and cyan transfer means. Reference numeral 8 is a sheet feeding unit for the recording medium 7 including a sheet feeding roller and a cassette, and 9 is a fixing unit. A black process may be provided before the yellow process or after the cyan process.

The latent image-forming developer 2 of each color is successively superposed and recorded at the position of each transfer means 60 on the recording medium 7 conveyed from the paper feeding means 8, and passes through the fixing means 9 to obtain a color recorded image. . In this case, after the recording of each color is completed, the developer on the developer carrying body is removed by a voltage applying unit (not shown) between each developer carrying body and the layer forming unit, and before the start of recording of each color. In the initial state, the developer is removed from the developer carrier, and by supplying the developer on the developer carrier before recording each color, the standby state and the non-use state are the same as in the single color mode. Spilling or scattering of the developer from the developer carrier 1 into the apparatus due to vibration or shock is eliminated. Further, spillage at the time of replacement of the developing unit such as replenishment of the developer is eliminated, and maintainability and handleability are improved.

Furthermore, the process for each color is an extremely simple process that does not have a photoconductor drum or cleaner, and can be made small and thin.
Also, it has few moving parts and is highly reliable. Further, the developing unit 4 and the transfer unit 6 and the like can be integrally arranged for each color, so that the color image forming apparatus is excellent in maintainability, handleability, and operability.

Next, the fifth embodiment of the image forming apparatus of the present invention will be described.
A description will be given based on the figure. The basic structure and operation of the third embodiment are similar to those of the conventional example shown in FIG. The developing device has the same structure as the developing unit 4 of the first embodiment, and therefore will be omitted. Uniformly on the latent image carrier 101 made of Se type photoconductor by the charger 102 + 800V
A latent image is formed in accordance with an image signal by an optical system 103 which is charged with a voltage of 660 nm and comprises an LED array having a wavelength of 660 nm and a SELFOC lens array (manufactured by Nippon Sheet Glass Co., Ltd.). At this time, the surface potential of the latent image portion becomes about +50 to + 100V. For the development, the developer 2 of the non-magnetic one-component toner is uniformly charged on the developer carrier 1 by the developing unit 4 to a surface potential of about +20 V, and the developer is uniformly thinned into 2 to 3 layers. The developer 2 is applied to the developer carrying member 1 by applying a DC voltage, which is substantially the same as the surface potential of the latent image carrying member 101 other than the latent image portion, to the developer carrying member 1. 1 to latent image carrier 10
It is performed by flying toward the latent image of 1. After recording, the developer 2 on the developer carrying member 1 is returned to the layer forming unit 3 side, that is, in the developing unit 4 by the voltage applying unit 11 between the developer carrying member 1 and the supply member 3 _a of the layer forming unit 3. Thus, the developer 2 can be removed from the developer carrier or the amount of adhesion can be reduced. For example, when the developing bias is set to + 800V, the voltage applying means 11 produces a potential difference of −50 to −100V,
That is, the application of a DC voltage of 700 to 750 V is most effective, and the developer 2 on the developer carrying member 1 can be almost removed. For the next recording, the developer carrying member 1 is rotated prior to the start of recording, so that a normal developer supply state is obtained.

Therefore, even in the image forming apparatus configured as described above, when the developing unit is replaced for replenishment of the developer, or when the developer 2 from the developer carrying body 1 of the developer 2 due to vibration or shock during standby or non-use. It is possible to obtain an image forming apparatus which can prevent spillage and scattering and has good maintainability and handleability.

The non-magnetic one-component toner as the developer 2 in the present embodiment, the removal of the developer from the developer carrying member has been described in the field, at least the layer forming member 3 _c after passing through the developer carrying member 1 above The developer 2 in the developing unit 4 may be a one-component or two-component toner as long as the developer 2 is uniformly thinned and is uniformly charged, and the layer forming means 3 is a stirring member. Also, a rigid blade _3c or the like which is not in contact with the developer carrying member 1 may be any layer forming means capable of applying an electric field or a magnetic field with the developer carrying member.

Further, in the first embodiment, it is more preferable that the developer 2 on the developer carrying member 1 is formed as a single thin layer from the viewpoint of the stability of the charging characteristics.

In this process, both reversal development and regular development are possible by changing the characteristics of the developer and the polarity of the bias, and the charging polarity by the layer forming means 3 is not restricted.

Further, the developing unit and the transfer unit, the developing unit and the latent image forming unit, the developing unit, the latent image forming unit and the transfer unit, and the like can be integrated, and an image forming apparatus having excellent reliability and operability is provided. be able to.

As described above, according to the present invention, an electric field is applied between the developer carrying member and the layer forming means to remove the developer from the developer carrying member, thereby making it possible to perform standby or non-operation. Image formation with excellent maintainability and handling, which prevents vibrations and shocks during use, and prevents developer from spilling or scattering from the developer carrier when the development unit is replaced, which could result in stains inside the device or installation location. It becomes a device and has an extremely great effect in practical use.

Further, according to the first and second aspects of the invention, the developing unit consisting of the developer carrying member, the developer and the layer forming means uniformly charges the developer on the developer carrying body to form a uniform thin layer, thereby forming the latent image forming means. To form a charged latent image of opposite polarity on the developer itself, and only the latent image is transferred to the recording medium by the transfer means. That is, latent image formation, development, and transfer are possible on the developer bearing member, and the process is extremely simple. In addition, the structure is only a developing unit that does not require a photoconductor drum or a cleaner, which enables downsizing and thinning. Further, where the user operates, including the replenishment of the developer, only the replacement of the developing unit is required, which makes maintenance and handling extremely easy.

Further, in the device, the movable part is only the developer carrying member, and the reliability is improved.

Further, according to the second aspect of the present invention, by sequentially arranging a plurality of colors in parallel, it is possible to provide a color image forming apparatus which has the effects of the basic configuration, is small and thin, and is easy to operate. The practical effect is great.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an image forming apparatus according to a first embodiment of the present invention, FIG. 2 is a partially enlarged view showing a latent image forming state of the same embodiment, and FIG. 3 is a voltage application of the same embodiment. FIG. 4 is a schematic enlarged sectional view of a color image forming apparatus according to a second embodiment of the present invention, and FIG. 5 is a third embodiment of the present invention. FIG. 6 is a schematic sectional view of an electrophotographic image forming apparatus, and FIG. 6 is a schematic sectional view of a conventional electrophotographic image forming apparatus. 1, 10Y, 10M, 10C ... Developer carrier, 2 ... Developer, 3
...... Layer forming means 4, 40Y, 40M, 40C …… Developing unit,
5,50Y, 50M, 50C ... Latent image forming means, 6,60Y, 60M, 60C ...
... transfer means, 7 ... recording medium, 8 ... paper feeding means, 9 ...
Fixing means, 11 ... voltage applying means, 12 ... developing bias applying means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideshi Ishihara 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-63-29766 (JP, A) JP-A-61-209461 (JP, A) JP-A-54-121738 (JP, A) JP-A-56-47061 (JP, A)

Claims (4)

[Claims] 1. A developing unit having at least a developer carrier and a layer forming means for forming a thin layer of the developer uniformly charged on the developer carrier, and a developing unit on the developer carrier. Between the recording means for directly forming a latent image on the developer, the transfer means for transferring the latent image-formed developer on the developer carrying member to the recording medium, the developer carrying body and the layer forming means. An image forming apparatus, comprising: a voltage applying unit that applies an electric field to the developing unit; and after the recording, the voltage applying unit returns the developer on the developer carrying member into the developing unit. 2. Development comprising at least a developer carrier corresponding to a plurality of color developers and a layer forming means for forming a thin layer of the developer uniformly charged on the developer carrier. A unit, a recording unit that directly forms a latent image on the developer on the developer carrier, a transfer unit that transfers the latent image-formed developer on the developer carrier to a recording medium, and the developer A voltage applying means for applying an electric field is sequentially arranged between the carrier and the layer forming means, and after the recording of each color, the developer on each developer carrier is applied to each developing unit by each voltage applying means. An image forming apparatus characterized by being returned to the inside. 3. A latent image forming means around the latent image carrier, a developer carrier for developing the latent image, and a layer forming a thin layer of the developer uniformly charged on the developer carrier. A developing unit that is integrated with a forming unit; a transfer unit that transfers the developer to a recording medium; a cleaning unit that cleans the developer on the latent image carrier; and a unit between the developer carrier and the layer forming unit. An image forming apparatus comprising: a voltage applying unit that applies an electric field to the developing unit and returning the developer on the developer carrying member to the developing unit by the applying unit after recording. 4. The image forming apparatus according to claim 1, 2 or 3, wherein the developer is a non-magnetic one-component toner.