JP2000085174A - Image forming device - Google Patents

Abstract

(57) [Problem] To provide a direct recording type image forming apparatus in which scattering of toner on a recording medium is efficiently and reliably suppressed, and a high quality image is generated. A recording medium is inserted between a control unit and a counter electrode, a predetermined voltage is applied to a gate unit of the control unit, and a toner is applied to the gate unit. In a direct recording type image forming apparatus that forms a toner image by controlling the passage of toner, a powder TP for reducing scattering of toner T is positioned upstream in the transport direction before the toner image is formed. The recording medium P is provided with powder adhering means 111 and 131 for adhering onto the medium P, and the powder is substantially the same color as the recording medium P or substantially transparent. With this configuration, the flying energy of the toner is absorbed and the scattering of the toner is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, etc., and more particularly, to a direct recording type image forming apparatus which forms an image by flying a developer onto a recording medium. The present invention relates to a forming apparatus.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus converts image information into optical information, irradiates it onto a uniformly charged photoconductor to form an electrostatic latent image, and holds the electrostatic latent image on a toner carrier. A so-called electrophotographic system in which a toner is developed in contact or non-contact with the toner to perform development, and is transferred and fixed on a recording medium has been widely used.

However, since the electrophotographic method basically uses a discharge phenomenon, the load on the environment such as generation of ozone cannot be ignored, the process is complicated, and the apparatus becomes large and the weight increases. There is a problem.

On the other hand, in recent years, rapid digitization by a computer or the like has progressed, and an image forming apparatus of a direct recording system for forming an image by directly flying ink or toner has been desired. The direct recording type image forming apparatus can realize high-quality printing equivalent to the electrophotographic type, and further, does not require an optical system and a photoconductor, so that the apparatus can be reduced in size and weight, and the number of parts can be reduced. The feature is that cost can be reduced from reduction.

However, in the above-described direct recording method, even when an intermediate recording medium is used, an image is formed by flying the developer on the recording medium, so that the developer has kinetic energy. And collides with the recording medium. At this time, if the kinetic energy of the developer cannot be absorbed, the developer bounces and scatters on the surface of the recording medium, so that the developer does not adhere to a desired image position, and the image quality deteriorates. Invite. Therefore, in the direct recording method described above, suppressing scattering of the developer on the recording medium is an important technical problem for preventing a decrease in image quality.

A document that discloses a technique for suppressing the scattering of the developer on the recording medium is disclosed in Japanese Patent Laid-Open No. 5-8 / 1993.
Japanese Patent Application Laid-Open No. 4964 and JP-A-9-263001.

In Japanese Patent Application Laid-Open No. 5-84964, a member capable of absorbing and temporarily holding flying energy of charged particles (developing agent) is provided as an intermediate recording medium, and an image is formed on the intermediate recording medium. Then, the image is transferred onto a sheet. By using a porous layer, an elastic layer, or the like on the surface of the intermediate recording medium, an image recording apparatus that does not degrade image quality even at high speed recording is disclosed. .

Japanese Patent Application Laid-Open No. 9-263001 discloses that
A humidifying mechanism is provided near the upstream side in the transport direction of the toner supply device with the aperture between the intermediate recording medium and the humidifying mechanism to attach water to the intermediate recording medium and improve the adhesion of the developer to the intermediate recording medium. An image forming apparatus is disclosed.

[0009]

As described above, Japanese Unexamined Patent Publication No.
The technique described in Japanese Patent No. 84964 is capable of providing an image forming apparatus having good image quality even at high speed by using a porous layer and an elastic layer on the surface of the intermediate recording medium. It is useful.

However, according to the technology described in the publication, when an elastic layer made of an elastomer such as rubber is used, the flying energy of the toner cannot be absorbed, and the intermediate layer having a porous surface cannot be absorbed. It is necessary to use a recording medium.

Considering the case where an intermediate recording medium having a porous surface is used, it is possible to absorb the flying energy of the toner by mechanically trapping the toner on the irregularities of the porous layer. However, there is a problem that transferability to a medium is deteriorated due to mechanical trapping. In addition, when the transfer from the intermediate recording medium is insufficient, the toner remains on the unevenness of the porous layer, and it becomes difficult to absorb the energy of the toner that flies next, which still causes deterioration in image quality. It will be.

As described above, Japanese Patent Application Laid-Open No. 9-263001
The technique described in Japanese Patent Application Laid-Open Publication No. H11-163,086 is useful in that water can be attached to an intermediate recording medium by a humidifying mechanism to improve the adhesive force of a developer.

However, according to the technology described in the publication, although the developer can be stably captured by using water, the developer adheres to the water and separates and spreads. This leads to a reduction in resolution, and furthermore, the presence of water makes it difficult to stably fix the water after evaporating it. That is, when water evaporates, there is a problem that the developers adhere to each other or as an intermediate recording medium and transfer becomes difficult.

As described above, according to the conventional technique, in a direct recording type image forming apparatus, the scattering of the developer on the recording medium cannot be suppressed efficiently and reliably, and the scattering of the developer still occurs. The degradation of image quality could not be prevented.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to efficiently and reliably suppress the scattering of a developer on a recording medium in a direct recording system. Another object of the present invention is to provide an image forming apparatus capable of generating a high-quality image.

[0016]

According to a first aspect of the present invention, there is provided a developer carrier for carrying a developer charged to a predetermined polarity, and a developer carrier having a predetermined gap with the developer carrier. A control means comprising a plurality of gate portions through which developer particles on the developer carrier can pass; and a voltage applying means which is disposed to face the developer carrier via the control means and is capable of applying a voltage. A counter electrode is provided, a recording medium is inserted between the control means and the counter electrode, and a predetermined voltage is applied to a gate portion of the control means based on an image signal corresponding to input image information to selectively gate. By controlling the passage of the developer in the section,
In an image forming apparatus for forming a developer image on a recording medium, the image forming apparatus further comprises a powder for reducing developer scattering when forming the developer image on the recording medium. An image forming apparatus, comprising: powder adhering means for adhering onto a recording medium before forming an image agent image, wherein the powder is substantially the same color or substantially transparent color as the recording medium.

Before forming the developer, a powder having substantially the same color or substantially transparent color as the recording medium is attached to the recording medium in advance, so that when the developer collides with the recording medium, an image is formed. Since the powder collides with the powder and moves, the kinetic energy of the developer during flight can be absorbed, and the scattering of the developer can be suppressed. Therefore, it is possible to eliminate problems such as deterioration of image quality and in-machine contamination due to scattering of the developer. Further, since the powder is substantially the same color or substantially transparent color as the recording medium, even if the powder is scattered due to the collision of the developer, the powder becomes invisible on the recording medium, and the image quality is deteriorated. Never do.

According to a second aspect of the present invention, the powder contains a constituent material of the developer.
An image forming apparatus according to (1). In addition to the contents of claim 1,
Since the powder contains the constituent material of the developer, both constituent materials can be used in common, and there is no need to use a new special member for the powder. The increase in cost can be suppressed. In addition, by making the constituent materials common to each other, it is also possible to make physical properties such as fixing property and charging property common, for example, not only to improve powder productivity, but also to fix fixing conditions and charging conditions. Can be matched, and the scattering of the developer can be suppressed without lowering the degree of freedom in designing the image forming apparatus.

The invention according to claim 3 is the image forming apparatus according to claim 1, wherein the powder is charged with the same polarity as the developer. In addition to the contents of claim 1, since the charging polarity of both the developer and the powder is the same, the members, circuits, configurations, etc. used for charging the developer can be made common, and the mass production effect can be reduced. Not only can this be expected, but product costs can be reduced. Further, the control of the powder can be made in accordance with the control of the developer, the degree of freedom in design can be improved, and the control can be simplified by simplifying the control. Further, when the components are made common, it can contribute to weight reduction of the device.

According to a fourth aspect of the present invention, the powder adhering means is arranged opposite to the powder carrier and supports a powder charged to a predetermined polarity, and is capable of applying a voltage. A second counter electrode, a recording medium is inserted between the powder carrier and the second counter electrode, and a predetermined voltage is applied to the second counter electrode based on an image signal corresponding to input image information. 4. The image forming apparatus according to claim 2, wherein a powder image is formed on the recording medium by applying the voltage.

Therefore, in addition to claim 2 or 3, since the powder applying means can be shared with the image forming section relating to the developer of the image forming apparatus, the same members, circuits, control software and the like can be diverted, and the product cost can be reduced. Reduction and improvement in design flexibility can be expected.
Further, since the control electrode portion is not required as compared with the image forming portion, the structure and the configuration are simplified, so that the cost can be reduced, the design flexibility can be improved, and the weight can be reduced.

According to a fifth aspect of the present invention, there is provided the power supply apparatus, wherein the powder adhering means is further disposed at a predetermined gap from the powder carrier, and a plurality of gates through which the powder on the powder carrier can pass. A second control means comprising: a recording medium inserted between the second control means and the second counter electrode; and a gate section of the second control means based on an image signal corresponding to input image information. 5. The image forming apparatus according to claim 4, wherein a powder image is formed on a recording medium by applying a predetermined voltage to the gate and selectively controlling the passage of the powder in the gate portion.

Therefore, in addition to the fourth aspect, by adopting a configuration substantially the same as that of the image forming section, it is possible to perform powder control comparable to image quality. It is possible to prevent the powder from unnecessarily adhering, the consumption of the powder can be minimized, and maintenance costs and service costs can be reduced. In addition, since the consumption of the powder can be minimized, the volume of the portion for accommodating the powder can be small, and the size and weight of the apparatus can be reduced.

The invention according to claim 6 is the image forming apparatus according to claim 1, wherein the particle diameter of the powder is substantially the same as or smaller than the particle diameter of the developer. Therefore,
In addition to the contents of claim 1, since the powder has a small particle diameter, the powder moves when the developer adheres, the developer moves, and the kinetic energy of the developer is effectively absorbed. Can be. Also, since the powder particle size is small, depending on the powder control method,
Detailed control becomes possible.

According to a seventh aspect of the present invention, the area where the powder adhering means applies the powder to the recording medium is substantially the same as or larger than the printing area using the developer. An image forming apparatus according to any one of the preceding claims.

Therefore, in addition to the contents of the first aspect, by effectively using the powder without waste, the consumption of the powder can be minimized, and the maintenance cost and the service cost can be reduced. be able to. In addition, since the consumption of the powder can be minimized, the volume of the portion for accommodating the powder can be small, and the size and weight of the apparatus can be reduced.

The invention according to claim 8 has a delay means for inputting an image signal to the second counter electrode or the second control means and for inputting the image signal to the control means after a lapse of a predetermined time. An image forming apparatus according to claim 4 or 5, wherein:

Therefore, in addition to the contents of claim 4 or 5,
Since image information (signals) input to the image forming unit can be used, there is no need to calculate or generate new control data at the stage of controlling the powder, and control is performed using only simple delay means. The method can be simplified, and the manufacturing cost required for the control unit can be reduced. Since the control is simplified, the processing speed can be increased, and the overall image forming speed can be improved.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A direct recording type image forming apparatus using a toner as a developer according to the present invention will be described below with reference to FIGS. In the following description, an image forming apparatus for negatively charged toner will be described in detail. However, when a positively charged toner is used, the polarity of the applied voltage to each member may be set accordingly.

FIG. 1 is an overall cross-sectional view of a direct recording type image forming apparatus, and FIG. 2 is a schematic cross-sectional view of a recording medium transport section and a printing section. A recording medium supply unit 4 is provided on a side portion of the apparatus main body. The recording medium supply unit 4 sends out the recording medium P from the recording medium accommodation unit 40 that accommodates the recording medium P. The pickup 41 includes a pair of registration rollers 42 that convey the supplied recording medium P in synchronization with the printing timing. The recording medium P supplied from the recording medium supply unit 4 includes a recording medium guide plate 43, a recording medium, and a recording medium. It is guided to the printing unit 1 via the medium pressing plate 44.

The recording medium supply unit 4 includes a recording medium detection sensor (not shown) for detecting that the recording medium P has been supplied, and the pickup roller 41 and the registration roller 42 include a controller unit 7. Is rotationally driven by a driving device (not shown) in response to the driving signal from.

On the downstream side of the printing unit 1 in the conveying direction of the recording medium P, a fixing unit 6 for fixing the toner image formed on the recording medium P in the printing unit 1 to the recording medium P by heating and pressing is provided. Is provided. The fixing unit 6 includes a heat roller 62 including a heater 61, a pressure roller 63, and a temperature sensor 64. The heat roller 62 is made of, for example, an aluminum tube having a thickness of 2 mm. A halogen lamp or the like is used as the heater 61, and a silicone resin or the like is used as the pressure roller 63. Then, the heat roller 62 and the pressure roller 63 which are arranged opposite to each other are biased at both ends of respective shafts by urging means such as springs (not shown) so that the recording medium P can be pressed therebetween.
For example, a load of 2 kg is applied.

The temperature sensor 64 is for measuring the surface temperature of the heat roller 62, and the measured value is inputted to a temperature control unit (not shown) of the controller unit 7. The temperature controller controls on / off and the like of the heater 61 based on the temperature detection result of the temperature sensor 64 to maintain the surface temperature of the heat roller 62 at, for example, 150 ° C. Further, the fixing unit 6 includes a paper discharge sensor (not shown) for detecting that the recording medium P has been discharged.

The material of the heater 61, the heat roller 62, the pressure roller 63 and the like and the surface temperature of the heat roller to be controlled are appropriately determined in consideration of the material of the toner and the process speed. Further, it goes without saying that the fixing method may be such that the toner image is fixed to the recording medium P by the action of only heating or only pressing.

Although not shown, on the discharge side of the recording medium P from the fixing unit 6, a discharge roller for discharging the recording medium P processed by the fixing unit 6 out of the machine, and a discharged recording medium P Receiving tray is provided. The heat roller 62, the pressure roller 63, and the discharge roller are rotationally driven by a driving device (not shown).

As shown in FIG. 1 and FIG.
A toner charger 3 for charging the toner to a predetermined polarity and value and supplying a predetermined amount of toner; a flight controller 2 for controlling the flight of the toner T supplied by the toner charger 3
And a counter electrode 11 disposed opposite to the toner charger 3 via the flight controller 2. The toner charger 3, the flight controller 2, and the counter electrode 11 are disposed in this order from the lower part in the vertical direction. . Therefore, in the present embodiment, a method in which the toner flies upward from the lower portion of the paper to the upper portion is employed.

FIG. 3 is a cross-sectional view of the toner charger 3. The toner carrier storage tank accommodates a toner carrier 31 and a supply roller 33 provided in non-contact with the toner carrier 31. 36, a stirring roller 37, and a toner storage tank 39 for storing the toner T.
Are disposed adjacent to each other in the horizontal direction.

The stirring roller 37 provided in the toner storage tank 39 is provided for stirring the toner T to prevent the toner T from being biased in the toner storage tank 39, and is driven by a driving unit (not shown). The mixture is appropriately stirred in the direction of arrow C in FIG. The toner carrier storage tank 36 is a cylindrical toner carrier 31 that carries and conveys the toner T. The toner carrier 31 is pressed against the toner carrier 31 to apply a predetermined charge to the toner T and is supported on the outer peripheral surface of the toner carrier 31. A regulating member (blade) 32 for regulating the thickness of the toner layer and a flexible member 34 arranged in contact with the supply roller 33. The space surrounded by these members forms a small chamber 35 and is configured to apply an appropriate powder pressure to the blade 32.

The surface of the toner carrier 31 has several μm to 10 μm.
The unevenness of about several μm is formed, and the toner T is pressed against the uneven surface of the toner carrier 31 by the blade 32, a predetermined charge is applied by friction charging, the layer thickness is regulated, and the toner T is conveyed to the printing area. . Then, the toner carrier 31 is rotationally driven at a speed of, for example, 60 mm / s in a direction indicated by an arrow B in FIG. However, the shape and the rotation speed of the toner carrier 31 are not particularly limited, and may be connected to a ground or a predetermined voltage applying unit as needed in controlling the flying property of the toner T.

The toner carrier 31 may be made of a metal material such as aluminum, a rubber material such as urethane, silicone or EPDM (ethylene propylene), and a conductive agent such as carbon black or ion. What is added is used.

In this embodiment, the blade 32 is of an elastic type, but may be of a rigid type. Materials include SUS (stainless), phosphor bronze, nickel-coated metals such as iron, urethane, silicone,
A rubber material such as EPDM (ethylene propylene) or a material obtained by adding a conductive agent such as carbon black ion to the above rubber material can be used.

The supply roller 33 has a regular hexagonal shape, and is driven in the direction of arrow A in FIG. The rotation speed of the supply roller 33 will be described later separately. The material of the supply roller 33 is SUS
(Stainless steel) A metal such as aluminum or a resin material such as polyacetal is used.

The toner T is a non-magnetic one-component toner obtained by adding a colorant, a conductivity control agent, and a release agent to a main resin composed of styrene acrylic or polyester and adding an external additive such as silica or titania, or Further, a magnetic toner to which magnetic powder is added is used. The unevenness (surface roughness) of the toner carrier 31, the linear pressure of the blade 32, and the material of these members may be appropriately set according to the required charge amount, transport amount, and layer thickness of the toner T.

The flight control unit 2 is arranged on the outer peripheral portion of the toner carrier 31 and controls the flight of the toner T conveyed by the toner carrier 31. FIGS. 4 and 5 show one example. . 4A is a plan view of the flight control unit 2, FIG. 4B is a cross-sectional view of the flight control unit 2, and FIG.
FIG. 3 is a detailed view of a printing unit 1 including a counter electrode 11.

The flight control section 2 has a ring-shaped control electrode 23, and applies a voltage corresponding to image information to each control electrode 23, thereby electrically connecting the gate 22 opened in the control electrode 23. The passage of the toner T from the toner carrier 31 to the counter electrode 11 is selectively controlled. Further, the flight control unit 2 has a configuration in which a control electrode 23 and a lens electrode 26 are arranged via an insulating layer 25, and a cover layer 27 is further provided.

The insulating layer 25 and the cover layer 27 are made of, for example, a polyimide resin having a thickness of 25 μm, and the control electrodes 23 are made of, for example, a copper foil having a thickness of 18 μm, and are arranged according to a predetermined arrangement. The lens electrode 26 is also made of 18 μm copper foil, like the control electrode 23, and is uniformly arranged on the entire surface of the control electrode 23, or is divided and arranged for each row (L direction in FIG. 4).

The diameters of the control electrode 23 and the lens electrode 26 are, for example, 230 μm and 280 μm. The control electrode 23, the insulating layer 25, the lens electrode 26, and the cover layer provided on each electrode are formed with a gate (opening) 22 therethrough so that the toner carrier 3
1 forms a passage portion of the toner T flying to the counter electrode 11.

Each gate is configured so that the center thereof coincides with the centers of the control electrode 23 and the lens electrode 26, and the opening diameter of the gate is formed to be, for example, 160 μm. The opening diameter of each electrode / gate 22 and the materials and thicknesses of the insulating layer 25 and the electrodes are not particularly limited.

The lens electrode 26 is provided for the purpose of converging the toner flow and shielding effect against the electric field, and may be provided as needed. Also, as the flight control unit 2,
A configuration in which a shield electrode is provided on the control electrode 23 via the cover layer 27 may be employed.

The control electrode 23 is connected to a control electrode voltage applying means 72 via a power supply line 24. As described above, the cover layer 27 is formed on the control electrode 23 to provide insulation between the control electrode 23 and the power supply line 24, between the control electrode 23 and the power supply line 24, and the toner carrier 31 and the counter electrode. 11 is secured. A pulse-shaped voltage is applied to the control electrode 23 according to the image information by the control electrode voltage applying means 72. When the toner T carried on the toner carrier 31 is caused to fly in the direction of the counter electrode 11 (hereinafter referred to as an ON potential), a voltage of, for example, +300 V is applied to the control electrode 23 to prevent the toner from flying ( Hereinafter, it is referred to as an off potential).
Is applied.

The flight control unit 2 having the above-described configuration includes:
The control electrode 23 is fixedly held on the electrode mount 21 (see FIG. 2) so that the control electrode 23 faces the toner carrier 31, and is arranged in parallel with the counter electrode. The counter electrode 11 is set so that the distance from the outer peripheral surface of the toner carrier 31 is, for example, 1 mm. A voltage of, for example, 2 kV is applied to the counter electrode 11 by a counter electrode voltage applying unit 71 in a printing operation. I have.

The electrodes between the counter electrode 11 and the toner carrier 31 include: 1) the toner T flying from the toner carrier 31;
Does not adhere to the flight control unit 2 to cause clogging;
2) It is required that the trajectory of the toner T passing through the flight control unit 2 does not expand, and 3) that the scattering of the toner T attached to the recording medium P can be suppressed.

On the other hand, the distance between the outer peripheral surface of the toner carrier 31 and the control electrode 23 is provided to be, for example, 100 μm. Under these conditions, when a voltage corresponding to the image information is applied to the control electrode 23 by the control electrode voltage application means 72, the electric field acting on the toner layer on the toner carrier 31 changes, and the toner T The flight will be controlled. The distance between the control electrode 23, the counter electrode 11, and the toner carrier 31 is not limited to the above-described numerical value.

The controller unit 7 includes a main control unit for controlling the entire image forming apparatus in addition to the counter electrode voltage application unit 71 and the control electrode voltage application unit 72, and the obtained image data to be printed. An image processing unit for converting the image data into a format, an image memory for storing the converted image data, and a flight control unit 2 for transferring the image data obtained from the image processing unit.
And an image forming control unit 7a for converting the image data to image data to be given to the image forming apparatus.

Next, the operation of the above-described direct recording type image forming apparatus will be described. First, when an image signal from a host computer (not shown) is sent to the controller unit 7, the controller unit 7 separates the image signal into a print start signal, a control signal such as a recording medium size, and image information. Pickup roller 4
1 to rotate the recording medium P stored in the recording medium storage section 40 until the recording medium P comes into contact with the registration roller 42. At this time, the operation of the pickup roller 41 is started after the presence of the recording medium P is confirmed by a recording medium detection sensor (not shown) provided in the recording medium accommodation section 40 for detecting the presence or absence of the recording medium.

Next, the registration roller 42 rotates at a constant speed, and the recording medium P is conveyed toward the counter electrode 11 at a constant speed while being pressed by the recording medium pressing plate 44. Next, in synchronization with the start of the rotation operation of the registration roller 42, the processing of image information is started in the image forming control unit of the controller unit 7, and the recording medium P is conveyed from a state of being in contact with the registration roller 42. Printing is started from a predetermined position calculated in the image forming control unit.

Next, the operation of the printing unit 1 will be described. The toner T stirred uniformly without unevenness by the stirring roller 37 is supplied to the toner carrier storage tank 36 and sent into the small chamber 35 by the supply roller 33. . The small chamber 35 is configured so that an appropriate powder pressure is applied to a contact portion between the toner carrier 31 and the blade 32, and the toner T is pressed and rubbed by the toner carrier 31 and the blade 32 to a predetermined It is charged to a polarity (negative polarity in this embodiment), and the gate 22 of the flight control unit 2 is rotated by the rotation of the toner carrier 31.
Is conveyed to a position facing.

Here, an ON voltage (for example, +
When a voltage of 300 V) is applied, a potential distribution is formed on the toner layer on the toner carrier 31 so as to be convex with respect to the toner carrier 31, and the toner T is transferred to the toner carrier in accordance with the electric field intensity in the toner layer. 31 through the gate 22 and the counter electrode 1
1 on the recording medium P. The recording medium P that has passed through the printing unit 1 is sucked and held through the opening 51 and conveyed to the fixing unit 6, where a stable image is formed on the recording medium P by heating and pressing.

In the above description, the image forming section for forming an image by the direct recording method has been described. However, the present invention is characterized in that a powder adhering section is provided in a stage preceding the image forming section. 6 to 1 for powder adhering part
4 will be described in detail below.

In the image forming apparatus according to the present invention, as shown in FIG. 9, a transparent fine powder TP is first adhered on a sheet-like recording medium P by a powder adhering portion, and The developer T is adhered so as to overlap with the image. With this configuration, when the developer adheres to the recording paper, the powder moves in accordance with the collision with the developer, so that the kinetic energy of the developer can be absorbed. Can be prevented from scattering due to the bound.

In order to efficiently absorb the kinetic energy of the developer, it is necessary that the powder move when the developer collides with the transparent powder. The particle diameter is desirably at least equal to or smaller than the particle diameter of the developer.

It is desirable that the powder contains at least one of the materials constituting the developer, and in this case, the material properties of the powder should be substantially the same as those of the developer. There is an advantage that no new material for powder is required. For example, when fixing is considered, good fixability to powder can be obtained under substantially the same conditions as those for the developer.

The formation of the powder layer is simple by applying the powder to the entire surface of the recording medium P, and the same ON voltage may be applied to all the electrodes. The consumption increases significantly. Therefore, the powder layer may be formed only in a necessary area, that is, an area corresponding to the printing area by the developer. In the following detailed description, it is assumed that the powder layer is selectively formed only in a specific area. A description will be given of the powder adhering portion that can be obtained.

(First Embodiment of the Present Invention) In the first embodiment, as shown in FIG. 6, a powder adhering section having substantially the same configuration as the image forming section is used. That is, as shown in FIG. 11, the powder adhering portion in FIG. 6 includes the powder charger 130, the second flight control portion 102, and the second counter electrode 111, and is transparent instead of the developer. It differs from the image forming section in that powder is used. The number attached to each component of the powder adhering portion is added with the hundreds digit, the last two digits represent members corresponding to a normal image forming portion, and description of overlapping portions will be omitted. . For example, the second counter electrode 111 of the powder adhering section corresponds to the counter electrode 11 of the image forming section.

The powder adhering section forms a powder layer of transparent powder in the same manner as the image forming section, but at this time, the area where the powder layer is formed is at least the image forming section downstream of the transport path. It is necessary to have an area approximately equal to the printing area. More preferably, as shown in FIG. 10, the area where the powder layer is formed (the transparent powder adhesion area 142) is slightly larger than the printing area 141. Scattering of the developer can be reliably suppressed. In this embodiment, the counter electrode is provided in each of the image forming section and the powder adhering section. However, for example, if the process is configured to pass through the counter electrode section twice, the counter electrode is commonly used. It is also possible.

In this embodiment, only the case where the cylindrical powder carrier 131 shown in FIG. 11 is used as the developer charger is described. A belt type in which the carrier is in a belt shape as shown in FIG. 15 may be used, or as shown in FIG. 14, a developer peeling member 150 in the counter direction for peeling the developer on the powder carrier. A so-called cloud method in which the powder is brought into a cloud shape (cloud shape) by contacting with a carrier may be applied.

Here, specific examples of the material used for the transparent powder include styrene-acryl / polyethylene as a developer resin and polyethylene / wax as a wax.
Positive charge charge control agents such as polypropylene, nigrosine dyes, quaternary ammonium salts, polymers having amino groups, etc. The amount of the control agent to be added may be appropriately set according to the fixing property and charging property of the powder. It is desirable that silica, titania and the like be charged to the same polarity as the powder developer.

As a developing method of the powder coating member, a two-component developing method using a carrier and a transparent member, a one-component contact developing method, and a one-component non-contact developing method are considered. In particular, in the case of the one-component non-contact developing method, AC superposition is more desirable.

(Second Embodiment of the Present Invention) This embodiment is intended to make the formation area of the powder layer slightly larger than the printing area. The second flight control unit 102 has control electrodes in the same manner as the flight control unit 2 of the image forming unit.
The electrode diameter of the control electrode of the second flight control unit 102 is made larger than the electrode diameter of the control electrode of the flight control unit 2. At this time, the number of control electrodes of the second flight control unit 102 is
May be the same as or less than the number.

However, when the number of control electrodes is made equal, there is an advantage that the second flight control unit 102 can be controlled using the same signal as the control signal given to the flight control unit 2. That is, in this case, as shown in FIG. 13A, the image signal 304 is sent to the distributor 302 via the determination signal providing circuit 303.

The discrimination signal providing circuit 303 supplies the same image signal 304 to the second flight control unit 102 and the flight control unit 2, so that a copy of the image signal is generated, and the discrimination signal of each image signal is generated. Granted. After that, the signal is distributed by the distributor 302 to a signal transmitted to the control electrode voltage application unit 305 of the second flight control unit 102 and a signal transmitted to the control electrode voltage application unit 300 of the flight control unit 2.

The second flight control section 102 forms a powder layer corresponding to the image formed by the transparent powder according to the image signal. At this time, since the electrode diameter of the control electrode of the second flight control unit 102 is larger than the electrode diameter of the control electrode of the flight control unit 2, the formation area of the powder layer is slightly larger than the printing area.

On the other hand, the signal sent to the control electrode voltage applying means 300 of the flight control unit 2 is sent from the distributor via the delay circuit. The delay circuit sends an image signal to the control electrode linear pressure applying means 300 of the flight control unit 2 in consideration of a difference between a powder layer forming time at the powder adhering unit and a printing time at the image forming unit. Therefore, in the image forming section, a desired image can be formed on the powder layer formed in the powder adhering section.
In the case of this embodiment, it is only necessary to simply make a copy of the image signal and send the signal with a delay, so that no burden is imposed on the control unit.

(Third Embodiment of the Present Invention) In the present embodiment, the signal area applied to the second flight control unit 102 is converted so that the powder layer forming area is wider than the printing area. . That is, in this case, as shown in FIG. 13B, the control electrode voltage application unit 3 of the second flight control unit 102
The signal sent to 05 is distributed by the distributor 302, converted by the signal conversion circuit 306, and sent to the second control electrode voltage applying means 305.

The signal conversion performed by the signal conversion circuit 306 is achieved by, for example, performing signal conversion so that electrodes located around the print area are turned on. That is,
The electrodes around the electrode to which the on-voltage is applied may be turned on. In this case, the number of control electrodes of the second flight control unit 102 may be the same as that of the flight control unit 2.

As a signal conversion performed by the signal conversion circuit 306, for example, a method of lowering the resolution of an image signal supplied to the second flight control unit 102 is considered. That is, by lowering the resolution, the formation region of the powder layer is enlarged more than the printing region. In this case, the number of control electrodes of the second flight control unit 102 is reduced according to the resolution. Also, in this case, since only the resolution needs to be reduced, it is not necessary to generate another data at the same resolution, and the burden on the control unit can be reduced.

(Fourth Embodiment of the Present Invention) In this embodiment, the distance between the powder charger 130 and the second counter electrode 111 can be increased without converting the signal given to the second flight controller 102. By making the distance longer than the distance between the toner charger 31 and the counter electrode 11 in the image forming section, the area where the powder layer is formed is made wider than the printing area.

That is, in this embodiment, the powder is spread (scattered) on the recording medium P by increasing the flying time of the powder.
Is used. In this embodiment, the distance is simply changed, and a detailed description is omitted. In the present embodiment, although there is a possibility that the degree of freedom may be impaired structurally, it can be implemented without performing complicated control. Further, although the powder is scattered on the recording medium, the powder is originally transparent, so that there is an advantage that the image quality is not affected at all.

(Fifth Embodiment of the Present Invention) FIG. 7 is a view for explaining a printing process according to this embodiment. 7 includes a powder charger 130 (see FIG. 11) and a second counter electrode 111. The second flight control unit 102 is omitted. 1
2 is provided. However, although a segment electrode is formed in the control electrode, a gate through which the developer passes is not provided.

In the example shown in FIG. 7, a non-contact type in which the recording medium and the powder carrier are separated from each other, but a contact type as shown in FIG. 8 may be used. In this case, in order to make the formation region of the powder layer wider than the printing region,
It goes without saying that the method described in the embodiment can be used. 13. Instead of the second control electrode voltage applying means 305 in FIG.
May be used.

The above is the description of the embodiment of the present invention. In the above embodiment, only the case where a transparent powder is used is described. For example, a white powder such as titanium dioxide and zinc oxide is used for the powder. A white powder to which a pigment is added may be used. Even when a white powder is used, since the color of the powder is almost the same as the color of the recording medium, the scattering of the developer can be suppressed without affecting the image quality.

[0082]

According to the first aspect of the present invention, in a direct recording type image forming apparatus, powder for reducing developer scattering when forming a developer image on a recording medium is used. A powder adhering means for adhering to a recording medium before forming a developer image, wherein the powder is substantially the same color or a substantially transparent color as the recording medium, forming a developer. By previously adhering a powder having substantially the same color or substantially transparent color as the recording medium on the recording medium in advance, when the developer collides with the recording medium, Since the body moves, the kinetic energy of the developer during the flight is absorbed, and there is an effect that scattering of the developer can be suppressed.

Therefore, it is possible to eliminate problems such as deterioration of image quality and in-machine contamination due to scattering of the developer. Further, since the powder is substantially the same color or substantially transparent color as the recording medium, even if scattering of the powder occurs due to the collision of the developer,
The image cannot be seen on the recording medium, and the image quality does not deteriorate.

According to the second aspect of the present invention, since the powder contains the constituent material of the developer, in addition to the effect of the first aspect, the powder is formed of the developer. By containing the constituent materials, both constituent materials can be used in common, there is no need to use a new special member for the powder, and it is possible to suppress an increase in cost when the powder is attached. it can. Also, by sharing the constituent materials of both,
It is also possible to share physical properties such as fixing property and charging property, for example, not only to improve powder productivity, but also to match fixing conditions and charging conditions, etc., and to design an image forming apparatus. There is an effect that the scattering of the developer can be suppressed without lowering the degree of freedom of design at the time.

According to the third aspect of the present invention, the powder is charged to have the same polarity as that of the developer. Since the charging polarities of the two are the same, members, circuits, configurations, and the like used for charging the developer can be made common, so that not only the mass production effect can be expected, but also the product cost can be reduced. Furthermore, the control of the powder can be adapted to the control of the developer, increasing the degree of freedom in design, simplifying the control by simplifying the control, and reducing the weight of the device when common components are used. There is an effect that it can also contribute to the conversion.

According to the fourth aspect of the present invention, the powder adhering means is provided with a powder carrier for supporting powder charged to a predetermined polarity, and is arranged opposite to the powder carrier to apply a voltage. A second counter electrode capable of performing the above operation, wherein the powder carrier and the second
Forming a powder image on the recording medium by inserting a recording medium between the opposing electrodes and applying a predetermined voltage to the second opposing electrode based on an image signal corresponding to the input image information; Features.

Therefore, in addition to the effect of the second or third aspect, since the powder applying means can be shared with the image forming section relating to the developer of the image forming apparatus, the same members, circuits, control software and the like can be used, and the product cost can be reduced This has the effect of reducing the number of components and improving the degree of freedom in design. Further, since the control electrode portion is not required as compared with the image forming portion, the structure and configuration are simplified, and there is also an effect that cost can be reduced, design flexibility can be improved, and weight can be reduced.

According to the fifth aspect of the present invention, the plurality of powder adhering means are further disposed at a predetermined gap from the powder carrier, and are capable of passing the powder on the powder carrier. A recording medium is inserted between the second control means and the second counter electrode, and based on an image signal corresponding to input image information, the second control means is provided. Since a powder image is formed on a recording medium by applying a predetermined voltage to the gate portion and selectively controlling the passage of the powder in the gate portion, a feature is provided. , By taking the substantially same configuration as the image forming unit,
Powder control comparable to image quality can be performed.

Therefore, it is possible to prevent the powder from unnecessarily adhering, for example, by adhering the powder to the entire surface of the recording medium. Costs and the like can be reduced. In addition, since the consumption of the powder can be minimized, the volume of the portion for accommodating the powder can be reduced, and the apparatus can be reduced in size and weight.

According to the sixth aspect of the present invention, the particle size of the powder is substantially the same as or smaller than the particle size of the developer. Since the particle size of the powder is small, the powder moves when the developer adheres,
The developer moves and can effectively absorb the kinetic energy of the developer. In addition, since the powder particle size is small, there is an effect that detailed control is possible depending on the powder control method.

According to the seventh aspect of the present invention, the area where the powder adhering means applies the powder to the recording medium is substantially the same as or larger than the printing area using the developer. In addition to the effects of the first aspect, by effectively using the powder without waste, the consumption of the powder can be minimized, and maintenance costs and service costs can be reduced. In addition, since the consumption of the powder can be minimized, the volume of the portion for storing the powder can be reduced, and the device can be reduced in size and weight.

According to the eighth aspect of the present invention, the second
An image signal is input to the counter electrode or the second control means, and a delay means for inputting the image signal to the control means after a predetermined time has elapsed is provided. Therefore, the image information (signal) input to the image forming unit can be diverted, and there is no need to newly calculate or generate control data at the stage of controlling the powder. The control method can be simplified, and the manufacturing cost required for the control unit can be reduced. Since the control is simplified, there is an effect that the processing speed can be increased and the entire image forming speed can be improved.

[Brief description of the drawings]

FIG. 1 is an overall schematic sectional view of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view illustrating a printing process unit of the image forming apparatus according to the embodiment of the present disclosure.

FIG. 3 is an overall sectional view of the toner charger according to the embodiment of the present invention.

4A and 4B are diagrams for explaining a configuration of a flight control unit according to the embodiment of the present invention, wherein FIG. 4A is a plan view of the flight control unit,
(B) is a sectional view of the flight control unit.

FIG. 5 is an explanatory diagram for describing a printing unit according to the embodiment of the present invention.

FIG. 6 is a partially enlarged cross-sectional view illustrating a configuration when a second flight control unit is used as a powder attachment unit according to the embodiment of the present invention.

FIG. 7 is a partially enlarged cross-sectional view of another embodiment of the present invention, in which a second flying control unit is used as a powder adhering unit and is arranged in a non-contact manner with a recording medium.

FIG. 8 is a partially enlarged cross-sectional view of a case where a second flying control unit is used as a powder adhering unit according to another embodiment of the present invention, and is arranged in contact with a recording medium.

FIG. 9 is an explanatory diagram for explaining that a transparent powder is attached to a recording medium and a developer is attached to the transparent powder according to the embodiment of the present invention.

FIG. 10 is an explanatory diagram for describing a preferred positional relationship between a printing region and a transparent powder attachment region according to the embodiment of the present invention.

FIG. 11 is an overall sectional view of the powder charger according to the embodiment of the present invention.

12A and 12B are diagrams for explaining the structure of a second counter electrode according to another embodiment of the present invention, wherein FIG. 12A is a plan view and FIG. 12B is a cross-sectional view.

FIG. 13 is a block diagram showing a state in which an image signal is distributed and sent to first and second control electrode voltage applying means according to another embodiment of the present invention. ,
(B) shows the case where signal conversion is performed after distribution.

FIG. 14 is a cross-sectional view according to the embodiment of the present invention in a case where a cloud system is adopted for the powder charger.

FIG. 15 is a cross-sectional view of a case where a belt type is adopted for the powder charger according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printing part 2 Flying control part 3 Toner charger 11 Counter electrode 22 Gate 23 Control electrode 30 Toner charger 31 Toner carrier 71 Counter electrode voltage applying means 72 Control electrode voltage applying means 102 Flight control unit 111 Control electrode 111 Counter electrode 130 Powder charger 131 Powder carrier 141 Printing area 142 Transparent powder adhesion area 300 Control electrode voltage applying means 301 Delay means 302 Distributor 303 Discrimination signal providing circuit 304 Image signal 305 Second control electrode voltage applying means 306 Signal conversion Circuit 307 Second counter electrode voltage applying means

Claims (8)

[Claims] 1. A developer carrier for carrying a developer charged to a predetermined polarity, and a developer arranged on the developer carrier with a predetermined gap from the developer carrier. A control unit including a plurality of gates through which particles can pass; and a counter electrode that is disposed to face the developer carrier and the control unit and that can apply a voltage, and that a voltage is applied between the control unit and the counter electrode. Through the recording medium, based on the image signal according to the input image information, by applying a predetermined voltage to the gate portion of the control means, by selectively controlling the passage of the developer in the gate portion, In an image forming apparatus for forming a developer image on a recording medium, the image forming apparatus further comprises: a powder for reducing developer scattering when forming the developer image on the recording medium; A powder adhering means for adhering to the recording medium before the formation of the image agent image, Kikotai image forming apparatus which is a recording medium having substantially the same color or substantially transparent color. 2. The image forming apparatus according to claim 1, wherein the powder contains a constituent material of the developer. 3. The image forming apparatus according to claim 1, wherein the powder is charged to the same polarity as the developer. 4. The powder adhering means includes a powder carrier for supporting powder charged to a predetermined polarity, and a second counter electrode disposed opposite to the powder carrier and capable of applying a voltage. By inserting a recording medium between the powder carrier and the second counter electrode and applying a predetermined voltage to the second counter electrode based on an image signal corresponding to the input image information, The image forming apparatus according to claim 2, wherein a powder image is formed thereon. 5. The second control means, further comprising a plurality of gates, wherein the powder adhering means is further disposed at a predetermined gap from the powder carrier, and is capable of passing powder on the powder carrier. A recording medium is inserted between the second control means and the second counter electrode, and a predetermined voltage is applied to a gate portion of the second control means based on an image signal corresponding to input image information. 5. The image forming apparatus according to claim 4, wherein a powder image is formed on a recording medium by selectively controlling passage of the powder through the gate unit. 6. The image forming apparatus according to claim 1, wherein the particle diameter of the powder is substantially the same as or smaller than the particle diameter of the developer. 7. The image forming apparatus according to claim 1, wherein an area where the powder applying means applies the powder to a recording medium is substantially the same as or larger than a printing area using a developer. 8. A device according to claim 4, further comprising delay means for inputting an image signal to said second counter electrode or said second control means and inputting the image signal to said control means after a predetermined time has elapsed. Or the image forming apparatus according to claim 5.