JP3716065B2 - Electrophotographic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic printer, and more particularly to a printer including a photoconductor having an amorphous silicon photoconductor layer on a conductive substrate.
[0002]
[Prior art]
An electrophotographic apparatus provided with a photoreceptor having a conventional amorphous silicon-based photoconductor layer on a conductive substrate is described in Japanese Patent Publication No. 5-68702 in order to prevent occurrence of printing defects due to surface oxidation at high humidity. In some cases, a heating means is provided on a part of the photoconductor, and the temperature of the photoconductor is heated from 40 ° C. to 200 ° C. after the process is completed.
[0003]
In addition, as described in JP-A-8-227240, by fixing the toner on the recording medium with the heat roller and the pressure roller, the guide plate forming the conveyance path is heated by the waste heat of the heat roller. In some cases, the toner before fixing is heated to improve the fixing efficiency of the toner onto the recording medium and to reduce the amount of dirt on the fixing device.
[0004]
[Problems to be solved by the invention]
In the former, no consideration is given to the complexity of the structure and the cost increase due to the newly equipped heating means dedicated to the photoreceptor.
[0005]
In the latter, the direct heat transfer from the heated guide plate to the toner is mainly based on the range, so the efficiency varies greatly depending on the distance between the toner and the guide plate, the color of the guide, and the color of the toner. No consideration has been given to the above conditions. For this reason, the color toner cannot be sufficiently heated depending on the color, and therefore a sufficient effect cannot be expected.
[0006]
In order to solve the above-described problems, an object of the present invention is to provide an electrophotographic apparatus that prevents oxidation of the surface of a photoconductor with a simple configuration without providing a heating unit dedicated to the photoconductor.
[0007]
Another object of the present invention is to provide an electrophotographic apparatus capable of sufficiently heating not only the toner color but also the toner before fixing.
[0008]
[Means for Solving the Problems]
The object is to provide an exposure device for forming a latent image on a photoreceptor having an amorphous silicon photoconductor layer on a conductive substrate, a developing device for forming a toner image on the latent image, and recording the toner image. Transfer means for transferring to the medium, fixing means for fixing the toner image transferred by the transfer means , a cover covering the periphery of the fixing means, and air in the cover heated by heat generated by the fixing means In an electrophotographic apparatus provided with a blower that blows air and a blower passage that connects the cover to the vicinity of the surface of the photoreceptor,
This can be achieved by providing a direction switching means in the air passage and selectively blowing air to either the surface of the photoreceptor or the transferred toner image.
[0009]
Further, the above object is achieved by providing temperature detecting means for detecting the temperature of the surface of the photosensitive member , and when the temperature is 40 ° C. or higher, the air is blown to the transferred toner image .
[0010]
Moreover, the said objective is achieved by the said ventilation path comprising the heat-resistant guide member, and the ventilation path surface of the said heat-resistant guide member being black .
[0011]
The above object is achieved by controlling the direction switching means so that the air in the cover heated by the heat generated by the fixing means hits the photosensitive member when the apparatus is started up .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described.
[0014]
FIG. 1 is a configuration diagram of an electrophotographic apparatus of the present invention.
The electrophotographic apparatus 110 includes an insertion port 33 into which a recording medium (not shown) is inserted, a paper pan 12 as a first guide and a paper guide 15 as a second guide that form a conveyance path, and conveyance as conveyance means. Drive rollers 10, 14, 18, 30, and 34 are disposed.
[0015]
Further, among these conveyance drive rollers 10, 18, 30 are elastic members 17, 31 such as springs, respectively, in order to cope with changes in the thickness of various recording media from cut sheets to a plurality of sheets bound. 36, and the elastic members 17, 31, and 36 are supported by drive sources 16, 32, and 35 such as solenoids. The transfer roller 4 serving as a transfer unit is also a drive roller. These drive sources, drive rollers, and the like are driven by a drive motor 103.
[0016]
In the case of an apparatus dedicated to a thin recording medium, the drive sources 16, 32, and 35 may be omitted, and the drive rollers 18 and 30 may be driven rollers.
[0017]
The transfer roller 4 is composed of conductive rubber and a cored bar, and is loaded with a high voltage by the variable high voltage power source 1. Further, the force applied by the transfer roller 4 to the photosensitive drum 22 as the photosensitive member can be controlled by the spring 3 and the solenoid 2.
[0018]
Note that the intervals between the conveyance drive roller 10 and the transfer roller 4 and between the conveyance drive roller 14 and the transfer roller 4 are at least shorter than the length in the conveyance direction of the recording medium.
[0019]
Further, there may be a case where a recording medium surface cleaning means such as an oil-absorbing rubber cleaning roller or a cleaning pad is provided between the insertion port 33 and the photosensitive drum 22.
[0020]
The fixing roller 9 serving as a fixing unit serves as a driving roller, and is used to convert a toner image attached to the recording medium with an electric adsorption force or the like into a permanent image by heat and pressure. Therefore, it has means necessary for fixing such as a heat source and a temperature sensor.
[0021]
The recording medium inserted from the insertion port 33 is detected by a sensor (not shown) provided at the insertion port 33. The detected information is transmitted to the interface unit 100, the printing unit 101 calculates printing control data, and the control unit 102 performs printing control. Note that the print control data may be sent by communication from another computer or the like.
[0022]
In addition, from the thickness of the recording medium detected by the thickness detection sensor 6 or the recording medium thickness data inputted in advance, the arithmetic unit is required to generate the optimum pressing force of the transfer roller 4 and this pressing force. The initial deformation amount of the spring 3 is calculated, the amount of movement of the drive source 2 is determined from the calculation result, and data such as the pressing force and timing are sent to the control unit 102. In addition, the optimum transfer voltage and timing for loading the voltage are calculated by the calculation unit 101 based on the recording medium thickness information, and the variable high voltage power source 1 is controlled through the control unit 102. The variable high voltage power source 1 is grounded through the ground 5. If the thickness of the recording medium is uniform or 0.5 mm or less, the thickness detection sensor 6 may not be provided, and the variable high voltage power source 1 and the pushing force may be constant.
[0023]
The print control data is developed by the computing unit 101, and once the surface of the photosensitive drum 22 is cleaned by the cleaning mechanism 28, and then the charge is removed by the charge eliminator 27, and then uniformly by the charger 23. A latent image is created on the charged photosensitive drum 22 with light from an exposure device 24 such as a laser or LED. Then, toner 26 is placed on the latent image from the developing unit 25 onto the photosensitive drum 22 to form a toner image. For this purpose, a static eliminator 27, a charger 23, an exposure unit 24, and a developing unit 25 are close to the photosensitive drum 22.
[0024]
The toner image is transferred onto the recording medium by an electric field applied by the variable high voltage power source 1 between the photosensitive drum 22 and the transfer roller 4, and is fixed by the fixing roller 9, the drive source 35 and the spring 36, and the conveying roller 10. . At this time, the calculation unit 101 determines the fixing pressure applied to the booklet from the information of the thickness sensor 6 and the information such as the conveyance speed, and controls the driving source 35 to apply an appropriate transfer pressure to the recording medium. The fixed recording medium is discharged out of the electrophotographic apparatus by the fixing device 9 and the conveying roller 10.
[0025]
In order to use the heat generated by the fixing roller 9 for preventing oxidation of the surface of the photosensitive drum 22 and improving the fixing efficiency of the toner, the apparatus of this embodiment has the following configuration.
[0026]
Hereinafter, the features and operations of this apparatus will be described with reference to the drawings of the printing mechanism section shown in FIGS.
[0027]
When the power is turned on, the fixing roller 9 is heated while rotating. The surface temperature of the fixing roller 9 is detected by a sensor 105 which is a temperature detecting means, and is controlled to be about 150 ° C. or higher. When the fixing roller 9 is heated, ambient air is also heated accordingly. A fixing cover 40 is provided on the upper surface of the fixing roller 9 so as to accumulate this heat.
[0028]
As shown in the air flow 104, the air around the fixing cover passes through the gap between the fixing cover 40 and the paper pan 12, is introduced from between the fixing cover 40 and the paper pan 12, and is heated in the fixing cover 40. Then, the blower 8 turns into hot air 11 and is sent as hot air 11 along a flow path formed by the heat-resistant guide 13, the paper pan 12, and a side plate (not shown). In addition, if the color of the conveyance surface of the heat-resistant guide 13 is black, there is an effect of further improving the efficiency of the width radiation heat.
[0029]
Control is performed by the switching means 37 so as to be substantially parallel to the paper pan 12 so that hot air hits the rotating photosensitive drum 22 at the time of startup (see FIG. 1). The reason why the photosensitive drum 22 is heated is to prevent the occurrence of defective printing due to oxidation of the surface at high humidity of the electrophotographic photosensitive member having the amorphous silicon photoconductor layer on the conductive substrate. By heating the photosensitive drum to about 40 ° C. or higher, oxidation on the surface of the photoreceptor can be removed. However, if the glass transition temperature of a general toner is set to 60 ° C. or higher, the toner remaining on the surface of the photosensitive drum 22 becomes rubbery and becomes viscous, and troubles may occur during transfer or cleaning. It is also necessary to set the temperature to 60 ° C. or lower.
[0030]
The photosensitive drum 22 is applied with a heat flow while rotating. When the temperature sensor 29 detects that the surface temperature of the entire photosensitive drum 22 has risen and has reached the predetermined temperature of 40 ° C. or more and about 60 ° C. or less, the preparatory stage is completed, and switching means as shown in FIG. The direction of 37 is controlled so that the hot air 11 flows toward the opening 38.
[0031]
The heat flow switched to the recording medium is then sent to the lower portion of the paper pan 12 through the opening 38. Then, it is discharged outside the electrophotographic apparatus 110 by an exhaust fan (not shown). Further, an exhaust pipe may be connected to the opening 38 and discharged to the outside.
[0032]
The opening 38 is preferably wider than the width of the recording medium 20 so that the hot air 11 can flow even while the recording medium passes over the opening 38, but it is the same as the recording medium 20 depending on the configuration of the entire electrophotographic apparatus. Alternatively, the width may be narrower than that of the recording medium 20, and heat may be accumulated when passing through the recording medium 20.
[0033]
When the recording medium 20 is inserted from the insertion port 33, the recording medium 20 is transported on the paper pan 12 by the transport rollers 18, 14, 34, 30 in the direction of arrow A, and the thickness detection sensor 6 detects the recording medium 20. The photosensitive drum 22 rotates in the direction of arrow B to form a toner image.
[0034]
The speed at which the recording medium 20 moves in the direction of arrow A coincides with the speed at which the photosensitive drum 22 moves in the direction of arrow B.
[0035]
Subsequently, when the recording medium 20 is conveyed in the direction of arrow A and contacts the photosensitive drum 22, a voltage calculated from the thickness information detected by the medium detection sensor 6 is loaded from the variable high voltage power source 1 to the transfer roller 4. In addition, a predetermined force is applied from the transfer roller 4 to the medium 20 by the drive source 2 giving the optimum deformation amount to the spring 3 so that the optimum transfer pressure calculated from the thickness information is applied to the recording medium 20.
[0036]
Since the switching unit 37 faces downward, the hot air heats the unfixed toner on the recording medium 20. At this time, as shown in FIG. 3, the angle of the switching unit 37 may be controlled so that hot air is more positively applied to the unfixed toner on the recording medium 20.
[0037]
When the recording medium 20 is conveyed to the fixing roller 9 side with respect to the switching means 37, hot air 11 blows against unfixed toner as shown in FIG. The unfixed toner 39 heated to the glass transition temperature or higher has increased tackiness and increased adhesion with the recording medium 20. The increase in the adhesive force improves the efficiency of fixing the toner onto the recording medium, so that it is possible to prevent the trouble that the unfixed toner 39 adheres to the fixing roller 9.
[0038]
As shown in FIG. 5, heat and pressure are applied to the recording medium 20 by the fixing roller 9 and the driving roller 10 to form a permanent image of the toner image 41, and then the recording medium 20 is discharged by the conveying rollers 9 and 10. Thus, the operation of transferring the toner image on the photosensitive drum 22 to the recording medium 20 is completed.
[0039]
【The invention's effect】
As described above, according to the present invention, even if the photosensitive drum is heated by using the waste heat of the fixing roller, the electrophotography can be provided with the photosensitive member having the amorphous silicon photoconductive layer on the conductive substrate. Further, it is not necessary to provide a heating means dedicated to the photosensitive drum, and it is possible to provide an inexpensive product with a simple configuration.
[0040]
In addition, since the switching valve is provided, the unfixed toner on the recording medium is heated by blowing the directly heated air against the unfixed toner at the time of operation, and warmed in advance regardless of the color of the unfixed toner. Fixing efficiency can also be increased. Furthermore, by facilitating fixing, it is possible to prevent fouling of the recording medium due to fixing efficiency and toner adhesion to the heat roller.
[Brief description of the drawings]
FIG. 1 is a schematic side view of an electrophotographic apparatus of the present invention.
FIG. 2 is a diagram for explaining the operation of the electrophotographic apparatus shown in FIG.
3 is a diagram for explaining the operation of the electrophotographic apparatus shown in FIG. 1. FIG.
4 is a diagram for explaining the operation of the electrophotographic apparatus shown in FIG. 1. FIG.
FIG. 5 is a diagram for explaining the operation of the electrophotographic apparatus shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Variable high voltage power supply 2, 16, 32, 35 ... Drive source, 3 ... Spring, 4 ... Transfer roller, 5 ... Ground, 6 ... Thickness detection sensor, 7 ... Air, 8 ... Blower, 9 ... Fixing roller 10, 14, 18, 30, 34 ... Conveyance drive roller, 11 ... Hot air, 12 ... Paper pan, 13 ... Heat resistant guide, 15 ... Paper guide, 17, 31, 36 ... Elastic member, 20 ... Medium, 22 ... Photosensitive drum , 23 ... charger, 24 ... exposure device, 25 ... developer, 26 ... toner, 27 ... static eliminator, 28 ... cleaning mechanism, 29 ... temperature sensor, 33 ... insertion port, 37 ... switching means, 38 ... opening DESCRIPTION OF SYMBOLS 40 ... Fixing cover 100 ... Interface part 101 ... Calculation part 102 ... Control part 103 ... Drive motor 104 ... Air flow 105 ... Temperature sensor 110 ... Electrophotographic apparatus.

Claims (4)

An exposure device that creates a latent image on a photoreceptor having an amorphous silicon photoconductor layer on a conductive substrate, a developing device that forms a toner image on the latent image, and the toner image is transferred to a recording medium. A transfer unit; a fixing unit that fixes the toner image transferred by the transfer unit; a cover that covers the periphery of the fixing unit; and a blower that blows air in the cover that is heated by heat generated by the fixing unit. In an electrophotographic apparatus comprising an air passage connecting the cover to the vicinity of the surface of the photoreceptor,
An electrophotographic apparatus comprising: a direction switching unit in the air passage; and the air is selectively blown to either the surface of the photosensitive member or the transferred toner image.   2. The electrophotographic apparatus according to claim 1, further comprising a temperature detection unit that detects a temperature of the surface of the photosensitive member, and when the temperature is equal to or higher than 40 ° C., the air is blown to the transferred toner image. .   The electrophotographic apparatus according to claim 1, wherein the air passage includes a heat resistant guide member, and the air passage surface of the heat resistant guide member is black.   3. The electrophotographic apparatus according to claim 2, wherein when the apparatus is started up, the direction switching unit is controlled so that the air in the cover heated by the heat generated by the fixing unit hits the photosensitive member.

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