Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G15/00—Apparatus for electrographic processes using a charge pattern
  • G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
  • G03G15/16—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer
  • G03G15/163—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer using the force produced by an electrostatic transfer field formed between the second base and the electrographic recording member, e.g. transfer through an air gap
  • G03G15/1635—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer using the force produced by an electrostatic transfer field formed between the second base and the electrographic recording member, e.g. transfer through an air gap the field being produced by laying down an electrostatic charge behind the base or the recording member, e.g. by a corona device
  • G03G15/1645—Arrangements for controlling the amount of charge
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G15/00—Apparatus for electrographic processes using a charge pattern
  • G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
  • G03G15/16—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer
  • G03G15/163—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer using the force produced by an electrostatic transfer field formed between the second base and the electrographic recording member, e.g. transfer through an air gap
  • G03G15/1635—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer using the force produced by an electrostatic transfer field formed between the second base and the electrographic recording member, e.g. transfer through an air gap the field being produced by laying down an electrostatic charge behind the base or the recording member, e.g. by a corona device
  • G03G15/165—Arrangements for supporting or transporting the second base in the transfer area, e.g. guides

Definitions

• the present invention relates to an image forming apparatus such as an electrophotographic copying machine or an electrophotographic printer using an electrostatic transfer process, particularly when a transfer material is conveyed by a transfer material conveying means.
• the present invention relates to an image forming apparatus configured to prevent a transfer material from being contaminated and a drum trap generated when the transfer material passes through a transfer point.
• 1 is a photoconductor drum
• 2 is a charger
• 3 is an exposure device
• 4 is a developing machine
• 5 is a transfer charger
• 6 is an erase lamp
• 7 is a cleaner
• 8 is a bell.
• Tokliner 9 is a transfer material
• 10 is a transfer material transport belt
• 11 and 12 are belt rollers.
• the transfer material 9 is transported by the transfer material transport belt 10 and is supplied to a nip area where the photosensitive drum 1 and the transfer material transport belt 10 are in contact. It is something.
• this image forming apparatus the following operations are performed. First, a uniform charge is applied to the surface of the photosensitive drum I by the charger 2, and a desired image to be formed in the exposure apparatus 3 is formed. By irradiating light corresponding to the above, an electrostatic latent image is formed on the surface of the photosensitive drum 1. Next, a visible image is formed on the photosensitive drum 1 by applying toner to the electrostatic latent image in the developing machine 4, and the visible image is transferred to the nip area. On the other hand, the transfer material 9 is supplied in the direction of the arrow A and is placed on the transfer material transfer belt 10, and then transferred to the nip area by the transfer material transfer belt 10.
• a charge having a polarity opposite to the charge of the visible image is applied to the transfer material transport belt 10 from the transfer charger 5, so that the visible image on the photosensitive drum 1 is the nip. Is transferred onto the transfer material 9 in the printing area.
• the transfer material 9 on which the visible image has been transferred to the surface is transported by the transfer material transport belt 10 for a predetermined distance, separated from the transfer material transport belt 10 and transported in the direction of arrow B, and then Then, an image is fixed on the surface of the transfer material 9 by a fixing device (not shown).
• the residual charge on the photoconductor drum 1 is eliminated by an erase lamp 6, and then the residual toner on the photoconductor drum 1 is removed by a cleaner 7 to form the next new image. Prepare for the cycle.
• the toner adhered on the transfer material conveying belt 10 is removed by the belt cleaner 8.
• a phenomenon in which the transfer material 9 passing through the transfer point is wound around the photosensitive drum 1 due to various causes, that is, a so-called drive May occur.
• a separate means for preventing drum traps has been added.
• a static eliminator such as an AC controller is provided at the separation part between the transfer material 9 and the transfer material transport belt 10, and the transfer material transport belt 10 is operated by the action of the static eliminator.
• the transfer material 9 can be easily separated from the paper.
• the precharger 14 and the conductive brush 15 electrically conductively grounded.
• the transfer material transport belt 10 and the transfer material 9 thereon are provided with charges of opposite polarities, respectively, and the transfer material 9 is electrostatically attracted to the transfer material transport belt 10 and the transfer material 9 is transferred.
• Japanese Patent Application Laid-Open No. H11-274173 discloses a structure in which the toner is wrapped around the photosensitive drum 1, that is, the drum is prevented from being trapped.
• the pressing device 16 or the pressing device 16 and the constant voltage element 17 are brought into contact with the transfer material transport belt 10.
• a conductive brush 18 that is conductively grounded via the conductive material 18 is disposed, and when the transfer material 9 is supplied, the pressing device 16 or the pressing device 16 and the conductive brush 18 are used.
• Transfer material 9 transfer material transfer bell The structure in which the pressure is applied to the object 10 is disclosed in Japanese Utility Model Laid-Open No. 62-1275651.
• the transfer material conveying belt has the purpose of cleaning the transfer material conveying belt, but it covers the entire belt width of the transfer material conveying belt and also has the purpose of cleaning the transfer material conveying belt.
• a drop blade is arranged in a direction orthogonal to the traveling direction of the belt, and the drop blade removes paper dust adhering to the transfer material transporting belt.
• the entire effective belt width of the transfer material conveying belt is disclosed in Japanese Patent Application Laid-Open No. 62-2755942, and for the purpose of cleaning the transfer material conveying belt similarly.
• the blade element is arranged so as to have a predetermined angle with respect to the joint portion of the transfer material transport belt, and the blade element moves the transfer material transport belt over the transfer material transport belt.
• a method for cleaning is disclosed in Japanese Utility Model Laid-Open No. 63-788964.
• transfer sheet 10 is pre-charged over the entire width thereof regardless of the shape or size of the transfer material 9, the transfer material transfer Toners that fall on box 10 are likewise accumulated evenly over their full width.
• the toner accumulated on the transfer material transport belt 10 adheres to the transfer material 9 transported on the transfer material transport belt 10, and the transfer material 9 is transported along with the transfer material 9.
• the transfer material transport belt 10 is removed from the transfer material transport belt 10 each time, but if a relatively small transfer material 9 is used continuously and a large transfer material 9 is used, the transfer material transport belt 10
• the toner which is not removed in each case above adheres to the leading end portion of the large transfer material 9 at a time, and contaminates the image to be formed.
• Japanese Patent Laid-Open No As described in JP-A Nos. 1-1127878 and 11-198786, the corona charger for transfer in the recording paper transporting body is upstream of the place where the charger is arranged. A separate corona charger for contact is arranged on the side, and the recording paper and the recording paper transporter are brought into close contact with each other immediately before transfer to the recording paper by this corona charger for contact (hereinafter referred to as “corona charger”). This is referred to as a close-contact type), or, as disclosed in Japanese Patent Application Laid-Open No.
• the recording paper transporter used here must retain the charge generated by the corona charger, and must be made of plastic film such as urethane rubber or PVDF. It consists of a single layer or a multilayer.
• the toner image is not formed in the leading edge portion of the recording paper, particularly, in an area within a range of at least 20 to 30 mm from the leading edge, that is, the area is a blank paper printing area. In some cases, drum trapping is likely to occur. On the other hand, when a toner image is formed in the area, the toner in that area is interposed between the photoconductor and the recording paper, and the drum trap phenomenon occurs. Difficult to read.
• the second is that when the recording paper is A4 or A3 size cut paper, such cut paper is used to cut large paper to a predetermined size.
• the cutting part of the recording paper (the leading end of the recording paper) bends in the cutting direction, so-called burrs occur. Ma
• the leading end of the recording paper may be bent for some reason other than the cut portion. If the recording paper has large burrs or bends at the leading edge, the drum trap phenomenon is likely to occur.In particular, the burrs or bends are directed toward the recording paper transport body. When they are transported, the frequency of occurrence of the drum trap phenomenon becomes considerably large.
• the frequency of occurrence of the drum trap phenomenon depends on the type of recording paper, such as thickness, paper quality ( This is particularly likely to occur with thin paper such as thin paper and recycled paper. This applies not only to ordinary paper but also to the case where a ⁇ ⁇ HP sheet such as a plastic film is used as the transfer paper.
• the conventional trap prevention means are not designed in consideration of the above-mentioned respective factors.
• the conventional The contact type and the quasi-contact type in the tip prevention means require an extra contact corona charger or an extra charging roller in addition to the transfer corona charger.
• the conventional trap-preventing means of the suction type requires an extra vacuum suction device, and furthermore, it is difficult to set the evening for sucking the recording paper. There is.
• the present invention has discovered that the cause of the transfer material wrapping around the image carrier at the time of transfer is discharge in a gap formed between the image carrier and the transfer material conveying means at the leading end of the image carrier.
• the method is characterized by controlling discharge in the gap to invalidate the discharge.
• the present invention provides a surface image carrier, means for forming a visible image on the image carrier according to image information to be projected, and transfer for carrying and transferring a transfer material.
• Material transfer means transfer means for transferring the visible image to the transfer material at a transfer point at which the image carrier and transfer material transport means come into contact, and the transfer material carried on the image carrier after the transfer Anti-winding means to prevent
• the winding prevention means comes into contact with the transfer material conveying means on the upstream side of the transfer point, and the transfer of the entire size that the transfer material conveying means can handle.
• the image forming apparatus further includes first means comprising a pressing guide disposed at a widthwise portion of the transfer material conveying means to which the material is conveyed.
• the present invention provides an image carrier, means for forming a visible image on the image carrier in accordance with image information to be projected, Transfer means for transferring the visible image to the transfer material at a transfer point at which the image carrier and the transfer material transport means come into contact with each other; and
• the anti-winding device includes a transfer material of all sizes that can be handled by the transfer material conveying device.
• the present invention provides an image carrier, means for forming a visible image on the image carrier in accordance with image information to be projected, Transferring the visible image at a transfer point where the image carrier and the transfer material conveying unit come into contact with each other.
• An image forming apparatus comprising: a transfer unit configured to transfer to a copying material; and a winding prevention unit configured to prevent the transfer material from being carried on the image carrier after the transfer and prevented from being conveyed.
• the transfer material is arranged by a plurality of projecting portions which are arranged in the full width direction of the transfer material transport means and are oriented in a non-parallel and non-perpendicular direction to the traveling direction of the transfer material transport means.
• a third means comprising a pressing guide for contacting the conveying means is provided.
• the present invention provides an image carrier, means for forming a visible image on the image carrier in accordance with image information to be projected, Transfer means for transferring the visible image to the transfer material at a transfer point at which the image carrier and the transfer material transport means come into contact with each other; and An anti-winding device that prevents the transfer material from being carried on the transfer material, wherein the anti-winding device contacts the transfer material transporting device upstream of the transfer point; and A pressing guide arranged in the width direction of the conveying means, and a projecting means for temporarily protruding the transfer material conveying means at a portion of the transfer material conveying means contacting the pressing guide.
• the present invention provides a photoreceptor that moves at a predetermined rate, an exposure device that exposes the photoreceptor, and develops an electrostatic latent image obtained by the exposure.
• a developing device In an electrophotographic recording apparatus having a transfer device for transferring a developed visible image to recording paper or the like, the transfer device includes a charger for applying a charge to a recording paper transporter, and the charger is transported. When the leading edge of the recording paper reaches the nip area, the recording paper transporter is charged, and at that time, the leading edge supply is applied to an area corresponding to the leading end of the recording paper of the recording paper transporter.
• the charge amount is made smaller than the charge amount applied to a region other than the leading end of the recording sheet of the recording sheet transporter, and the initial charge amount is recorded at the leading end by the charge.
• a fifth means is provided for selecting an electric field generated in a gap between a sheet and the recording sheet transporting body to a value which is equal to or less than an electric field for starting air discharge.
• the present invention provides a photoconductor that moves at a predetermined speed, an exposure device that exposes the photoconductor, and a device that develops an electrostatic latent image obtained by the exposure.
• the transfer device includes a conductive bias roller that presses a recording paper transport body toward the photoconductor. The bias roller applies a voltage to the recording paper transport when the leading edge of the transported recording paper reaches the nip area, and at this time, the bias roller corresponds to the leading edge of the recording paper.
• the tip application voltage applied to the recording sheet transporter is made smaller than the voltage applied to the recording sheet transporter corresponding to portions other than the leading end of the recording sheet, and the tip application voltage is set to this voltage.
• Figure 1 shows the relationship between the use of paper, that is, cut paper, and the winding of the cut paper around the photosensitive drum and the occurrence of so-called drum traps. The following description is based on the conventional device shown.
• the size (a, b in the figure) of the ball 76 is, for example, about 3 in the A4 size cut sheet of one sheet of 1 in 3 and weighing 65 g. 0 m or more and b is about 200 m or more.
• the burrs 76 face the transfer material transport belt 10 side.
• the present inventors have conducted experiments to confirm that a drum trap occurs when the drum is in operation, and that no drum trap occurs when the burr 76 faces the photoconductor drum 1 side. .
• Figure 26 shows the Passenger curve 72 showing the relationship between the discharge start voltage in air and the gap length, and the gap when the optimal charge is given to the transfer material transport belt 10.
• This is a graph showing a line 73 indicating the relationship with the air gap voltage.
• the air gap length at the intersection of the two lines 72 and 73 (about 10 m) is larger than the air gap length (about 10 m).
• FIG. 25 shows a state where the cut paper 9 exits the nip area.
• the present invention has been devised in consideration of the knowledge of the occurrence of the drum trap described above, and the first to fourth means of the present invention have the following effects.
• the burrs formed at the leading end of the transfer material which is the cause of the drum trap, are carried and conveyed in a state facing the transfer material conveyance belt. Even if this transfer material is used, the pressing guide and transfer material transfer When the paper passes through the gap between the transfer guide and the pressing guide, the shear stress between the pressing guide and the moving transfer material transport belt is applied to the transfer material. At the same time as reducing the size, the transfer material can be brought into close contact with the transfer material transport belt, and the transfer material can be guided to the nip area serving as the transfer point in a stable state. As a result, the size and number of gaps between the transfer material and the transfer material transport belt are reduced, so that discharges generated in the gaps are less likely to occur, and as a result, a drum trap is formed. Can be prevented from occurring.
• the pressing guide is provided only in a widthwise direction of the transfer material conveying belt, at a portion where all of the transfer materials of each size that can be handled by the transfer material conveying belt are conveyed. Because the toner is accumulated on the transfer material transport belt, the toner is transported between the pressing guide and the transfer material transport belt by the movement of the transfer material transport belt. Even after that, the toner is transferred and removed together with the transfer material every time the transfer material passes, and is not accumulated between the pressing guide and the transfer material transport belt. There is no dirt on the tip of the material due to the adhesion of the toner.
• the guide of the transfer material is performed over the entire width of the transfer material transport belt, and the pressing in the width direction of the transfer material transport belt is performed in accordance with the size of the transfer material. Since the width is selectively changed, the guide for the transfer material is effectively performed, and the pressing guide is selectively applied only to the portion where the transfer material is transferred on the transfer material transport belt. of A pressing force can also be applied, and the drum trap prevention function can be effectively used for all transfer materials.
• the toner accumulated on the transfer material transport belt does not accumulate in the pressing guide and the transfer material transport belt.
• the transfer material does not stain at the leading end due to the adhesion of the toner.
• the third means since the plurality of projecting means provided on the pressing guide are configured to come into contact with the transfer material transport belt, the transfer on the transfer material transport belt is performed.
• the pressing force of the pressing guide acts on the material, and the drum trap prevention function can be exerted on all transfer materials.
• the toner accumulated on the transfer material transport belt is Even if the toner is transferred to the pressing guide arrangement portion, the toner moves to the downstream side of the transfer material transport belt along the periphery of the plurality of projecting means, and easily passes through the pressing guide. It will be. For this reason, the toner is not blocked and accumulated at the portion where the pressing guide is disposed, and as with the above-described means, it is possible that the toner is not attached to the leading end of the transfer material due to the adhesion of the toner. Absent.
• the pressing guide is arranged.
• the drum trap prevention function can be exerted on all the transfer materials as in the above three methods.
• the first transfer is performed during the period when the transfer material is not being conveyed, for example, when the size of the transfer material is changed.
• the portion of the transfer material transport belt that is in contact with the pressing guide is temporarily deformed, so that the charge accumulated between the pressing guide and the transfer material transport belt is accumulated.
• the transferred toner is ejected by this deformation, and the ejected toner is transported by the transfer material transport belt, and then transferred by the cleaner to the transfer material transport belt. Removed from above. Therefore, at the time of the first transfer after the size is changed, no stain is generated on the leading end of the transfer material due to adhesion of toner.
• FIG. 37 is an enlarged configuration diagram showing a trap region where the photoconductor and the recording paper transport body encounter.
• 101 is a drum
• 102 is a photoreceptor on the surface of a drum 110
• 103 is a toner
• 1 0 4 0 is the recording paper
• 1 0 50 is the leading edge of the recording paper 1 0 4
• 1 0 6 0 is the recording paper transporter
• 1 0 7 0 is the gap
• 1 0 8 0 is the press Roller
• 1900 is a colony charger
• 1100 is a developing machine
• 1110 is a developing roller
• 111 20 is a constant current power supply.
• the width L between the varieties 150 and the recording paper transporter 160 is not larger than the width L. Is formed, a gap 1 0 70 mm of about 0, 1 to 10.0 mm is formed, and the leading end of the recording paper 1 0 4 0 containing this 1 0 0 0 is a blank area where no transfer is performed. Has become. Further, the current It from the constant current power supply 110 is supplied to the corona wire of the corona charger 109, but 10 to 30% of the current It is the corona wire.
• the charging current Ib flows into the recording paper transporter 1660 as a force, and the positive charge Q (coulomb / cm 2 ) of the recording paper transporter 1660 is accumulated. At this time, positive and negative charges are generated in the gap 170 based on the charge amount Q, and thereby an electric field Eair is formed.
• the recording paper 1100 is moved to the corona jailer 1900. Accordingly, the positive charges accumulated on the back surface of the recording paper transporter 1 0 6 0 are accumulated, and the positive charges accumulate on the surface of the photoreceptor 1 0 2 0. 30 is sucked onto the recording paper 104, and the visible image formed on the surface of the photoconductor 100 is transferred onto the recording paper 104.
• the transfer current Im flows through the colony charger 109.
• the recording paper 1 0 4 0 enters the colony jar 1 0 9 0, the leading edge
• the electric charge Q stored in the recording paper transporting body corresponding to the portion of the barrier 1 50 0 is, as shown by the curve ⁇ in FIG. 38B, the exit of the corona charger 1 90 It gradually increases before reaching the end L c.
• the void 107 0 When the electric field Ea ir reaches the electric discharge starting electric field Eb (30 kv / cm at atmospheric pressure) of the air, a discharge is generated in the void 170.When this discharge occurs, positive and negative charges are generated. Electric charge is generated, but the positive charge is attracted by the negative charge on the photoconductor 100 and injected into the recording paper 104, and the negative charge is
• the electric charge Q accumulated in the recording paper transporter corresponding to the above-mentioned portion of the column 150 is equal to the charge of the corona charger 1.
• the charge starts to be accumulated before reaching the entrance end La of the above-mentioned circuit, and then, the portion of the above-mentioned barrier 1500 starts from the above-mentioned entrance end La and becomes a coronal-jawer 1 Even if the amount of the electric charge gradually increases while being conveyed to the exit end Lc, at least the amount of the electric charge at the nip exit L no
• the present invention has been made based on such a principle, and the fifth means is a recording paper transporter.
• a charger (colonizer) for injecting electric charge into 106 0 is used, and the charger has a burr at the tip due to the charger.
• the charge applied to the leading end of the recording paper 104 is selected as the charge Q j smaller than the charge Q b, and the transfer efficiency of the charge other than the leading end of the recording paper 104 is maximized.
• Such a charge amount Qm is selected.
• the sixth means uses a bias roll for applying a voltage to the recording paper transporter 160, and the bias roll makes the recording paper 100 having a burr 150 at the leading end. 40
• the voltage to be applied to the leading end of the recording paper is selected as a voltage V j that is smaller than the voltage at which the charge amount Q b is generated.
• the charge amount of the portion other than the above-mentioned tip portion of 104 is selected as the voltage Vm that generates the charge amount Qm that maximizes the transfer efficiency
• Fig. 36 shows the amount of charge Q given to the recording paper transporter 160, the transfer efficiency (%) (curve 2), and the rate of drum trap generation of the recording paper 104 ( %) (Carb1) is a graph showing the relationship with.
• the transfer efficiency when the electric charge Q given to the recording paper transporter 160 is equal to or less than the electric charge Qb is equal to the electric charge for transfer.
• the recording paper transporter 1060 corresponding to the leading end has a transfer charge or a transfer voltage having the same polarity as the transfer charge or the transfer voltage, even though the transfer is insufficient. Since the charge amount or the underpressure is given, and the charge amount Qj is given to the recording paper transporting body 160 by that, the surface of the photosensitive body 100 And recording paper transport A transfer electric field acts between the recording medium and the recording medium, and a visible image on the surface of the photoconductor is also transferred to the leading end of the recording paper. In addition, a transfer charge or a transfer voltage sufficient for transfer is applied to the portion other than the leading end portion of the recording paper 104, so that clear transfer as before can be performed. Things.
• the transfer efficiency may be selected to be G 0% or more, preferably about 60 to 70%, and at that time, image deterioration hardly occurs. There is no practical problem.
• the present invention provides a so-called driver that does not cause deterioration of the transferred image at the leading end of the recording paper 104 and does not wrap the recording paper 104 around the photoconductor 102. It is possible to obtain an electrophotographic recording device that does not cause a trap phenomenon. o
• FIG. 1 is a configuration diagram showing an example of a conventional image forming apparatus.
• FIG. 2 and FIG. 2 are schematic configuration diagrams showing an example of a conventional anti-winding means.
• FIG. 3 is a schematic configuration diagram showing one embodiment of the image forming apparatus of the present invention.
• FIGS. 4 and 4 are schematic configuration diagrams showing the positional relationship between the guide and the belt in the embodiment.
• FIG. 5 shows the distribution of transfer paper transport means of various paper sizes.
• FIG. 4 is a top view showing an example of the arrangement.
• FIG. 6 is a perspective view showing an example of a pressing guide in the embodiment.
• FIG. 7 is a perspective view showing another embodiment of the pressing guide.
• FIG. 8 is a perspective view showing another embodiment of the pressing guide.
• FIG. 9 is a top view showing an example of the arrangement of various paper sizes on the transfer material conveying means.
• FIG. 10 is a perspective view showing another embodiment of the pressing guide.
• FIG. 11 is a block diagram showing an example of a control system for operating the selection addition guide.
• FIG. 12 is a block diagram showing another example of a control system for operating the selection additional guide.
• FIG. 13 is a perspective view showing another embodiment of the pressing guide.
• FIG. 14 is a perspective view showing another embodiment of the pressing guide.
• FIGS. 15A, 15B and 15C are perspective views showing another embodiment of the pressing guide.
• FIG. 16 is a perspective view showing another embodiment of the pressing guide.
• FIG. 17 is a perspective view showing another embodiment of the pressing guide.
• FIG. 18 is a perspective view showing another embodiment of the pressing guide.
• FIG. 19 is a perspective view showing another embodiment of the pressing guide.
• FIG. 20 is a perspective view showing another embodiment of the pressing guide.
• FIG. 21 is a schematic configuration diagram showing a toner removing unit.
• FIG. 22 is a schematic configuration diagram showing another example of the toner removing unit.
• FIG. 23 is an enlarged cross-sectional view showing burrs at a cut in the cut paper.
• FIG. 24 is a cross-sectional view illustrating a gap formed between the cut sheet and the transfer material conveying belt, and explaining a discharge in the gap.
• FIG. 25 is a schematic cross-sectional view showing the state of charge when the cut paper exits the zip region.
• Figure 26 is a graph showing the relationship between the Paschen curve and the gap voltage with respect to the gap size.
• FIG. 27 is a schematic sectional view showing a state immediately before the cut paper reaches the nip area.
• FIG. 28 is a schematic configuration diagram showing another example of the image forming apparatus of the present invention.
• FIG. 29 is an explanatory diagram showing a time change of the transfer current of the colony jersey.
• Fig. 30 is a block diagram showing the internal structure of the constant current power supply. It is.
• FIGS. 31A and 31B are explanatory diagrams showing a time change of the transfer current output from the constant current power supply.
• FIG. 32 is a schematic configuration diagram showing another example of the image forming apparatus of the present invention.
• Figure 33 is a graph showing the relationship between toner weight and optical reflection density.
• FIG. 34 is an explanatory diagram showing a time change of the applied voltage of the bias roller.
• FIG. 35 is a schematic configuration diagram showing another example of the image forming apparatus of the present invention.
• FIG. 36 is a characteristic graph showing the relationship between the charge amount, the transfer efficiency, and the lap ratio.
• FIG. 37 is a schematic configuration diagram for explaining the mechanism of the occurrence of a drum trap.
• FIGS. 38A and 38B are characteristic graphs showing the relationship between the position of the leading edge of the recording paper and the charge amount. as well as
• FIG. 39 is a configuration diagram showing an outline of the overall configuration of the electrophotographic recording apparatus.
• the image forming apparatus is an electrophotographic printer and the transfer material is a cut sheet, but the image forming apparatus of the present invention is Applications are limited to electrophotographic printers. Instead, it can be widely applied to those having an electrostatic transfer process, such as copiers and faxes.
• FIG. 3 is a configuration diagram showing a first embodiment of the image forming apparatus of the present invention.
• 1 is a photosensitive drum
• 2 is a charger
• 3 is an exposure device
• 4 is a developing machine
• 5 is a transfer charger
• 6 is an erase lamp
• 7 is a cleaner
• 8 is a belt charger.
• Liner 9 is the transfer material
• 10 is the transfer material transport belt
• 1 and 12 are the belt rollers
• 13 is the pressing guide, which are the same as the components of the conventional device shown in Fig. 1. The same components are denoted by the same reference numerals.
• a charger 2 an exposing device 3, a developing device 4, a transfer charger 5, an erase lamp 6, are provided around a photosensitive drum 1.
• Parts such as the cleaner 7 are arranged, and the transfer material 9 is transported by the transfer material transport belt 10, and is located in a nip area where the photosensitive drum 1 and the transfer material transport belt 10 are in contact with each other.
• a pressing guide 13 which constitutes an anti-winding means is provided on the upstream side of the nip area in the transfer material transport belt 10 so as to come into contact with the transfer material transport belt 10.
• the transfer belt 10 is disposed so as to form an acute angle with respect to the traveling direction of the transfer belt 10.
• the device of this embodiment basically performs the same operation as the conventional device shown in FIG.
• a uniform charge is given to the surface of the photoconductor drum 1 by the charger 2, and light corresponding to a desired image to be formed by the exposure device 3 is irradiated, and the surface of the photoconductor drum 1 is irradiated.
• An electrostatic latent image is formed.
• a toner is adhered on the electrostatic latent image by a developing machine 4 to form a visible image on the photosensitive drum 1, and the visible image is transferred to the nip area while the transfer material is transferred.
• the transfer material 9 is supplied from the direction of the arrow A and is placed on the transfer material transfer belt 10, and then transferred to the nip area by the transfer material transfer belt 10.
• the transfer charger 10 applies a charge having a polarity opposite to that of the visible image to the transfer material transport belt 10, so that the transfer charge is transferred to the transfer material belt 10 on the photosensitive drum 1.
• the visible image is transferred onto the transfer material 9 in the nip area.
• the transfer material 9 having the visible image transferred to the surface is transported by the transfer material transport belt 10 for a predetermined distance, then separated from the transfer material transport belt 10 and transported in the direction of arrow B. Next, an image is fixed on the surface of the transfer material 9 by a fixing device (not shown).
• the residual charge on the photoconductor drum 1 is eliminated by an erase lamp 6, and then the residual toner on the photoconductor drum 1 is removed by a cleaner 7, and the next new image is formed. Preparing for the formation cycle.
• the toner adhered on the transfer material conveying belt 10 is removed by the belt cleaner 8.
• the pressing guide 13 is arranged so as to be in contact with the transfer material transport belt 10 immediately before the zip region of the transfer material transport belt 10. Therefore, the transfer material 9 does not wind around the photoconductor drum 1 after passing through the nip area.
• the transfer material transport belt 10 is a dielectric belt in which fluorine resin is coated on both sides of urethane rubber, and has a surface resistivity at room temperature and humidity. about 1 0 1 2 ⁇ , used as body volume resistivity of about 1 0 1 1 ⁇ ⁇ cm, as a Guide 1 3 pressing, not using the things of My La-off Lee Lum made of ⁇ body .
• FIG. 4A is a diagram showing a detailed configuration of the guide 13.
• the guide 13 made of polyester is formed by a guide support member 13 A using, for example, polycarbonate. It can be mounted at a mounting angle of 0 (approximately 5-10 degrees).
• the rub depth D between the belt 10 and the thickness of about 250 millimicron thickness is about 2 millimeters.
• the guide I 3 attached in this manner has a tip with a zip width of about 5 to 15 millimeters. Contact with 10.
• FIG. 4B is a diagram illustrating a positional relationship between the guide 13 and the belt 10 in a state where the apparatus has stopped operating and a state where paper is not supplied. That is, the guide 13 is fixed to a printing unit (not shown) together with the drum 1, the charger 2 and the developing machine 4, but the belt 10 is a belt opening. It is fixed to a transfer unit (not shown) together with 2 and belt cleaner 8. Therefore, belt 10 is at the position shown by the solid line at the time of retraction, and at the same position as shown in FIG.
• the apparatus of this embodiment uses A 3, A 4, It is assumed that plain paper of each size of A5 is used, and Fig. 5 shows that plain paper 9 of each of these sizes is carried and transported on the transfer material transport belt 10. It indicates a normal position. As can be seen from FIG. 5, the plain paper 9 of each size is also transported with reference to the same side S of the transfer material transport belt 10, so that the plain paper 9 of the minimum size is A. Area a corresponding to 5 is an area that is always conveyed even with plain paper of each size.
• FIG. 6 is a configuration diagram showing a pressing guide 13 used in the present embodiment.
• the pressing guide 13 has a width corresponding to the area a of the transfer material conveying belt 10.
• the transfer material transport belt 10 is disposed in the area a so as to be orthogonal to the traveling direction of the transfer material transport belt 10.
• the location where the pressing guide 13 is located is as close to the transfer point as the closer to the transfer point, the more effective it is to prevent the drum from being trapped. It is preferable to arrange them.
• the press guide 13 Since the pressing guide 13 is always in contact with the transfer material transport belt 10, the press guide 13 is charged by friction with the transfer material transport belt 10, and the polarity of the charged charge is the polarity of the toner. When it is reversed, the toner on the photosensitive drum 1 or the toner floating in the air is attracted, and as a result, the toner is deposited on the upper surface of the pressing guide 13. Thus, the deposited toner falls off due to vibration of the apparatus and the like, and causes the transfer material 9 to become dirty.
• press guide 13 should be The transfer material transport belt 10 should not be charged to at least the opposite polarity to the charging polarity of the transfer material transport belt 10 when it rubs with the Jl 10. While the surface of the transfer material transport belt 10 is made of fluororesin, the surface of the pressing guide 13 is made of at least a fluororesin such as Teflon. The frictional electrification is hardly generated. With such a configuration, it is possible to prevent the toner from being attracted due to the frictional charging regardless of the charging polarity of the toner. Further, if the surface of the pressing guide 13 is made of at least Teflon, a secondary effect such that the releasability of the toner is improved is also exerted. A sheet of polyvinylidene fluoride (PVDF) may be used as the pressing guide.
• PVDF polyvinylidene fluoride
• FIG. 13 is a configuration diagram showing another example of the pressing guide 13 used in the device of the first embodiment.
• This example is a pressing guide I3 having a two-layer structure in which an aluminum thin film 20 is adhered to the back surface of a mylar film 19 by a vacuum evaporation method. It is connected to the ground by a conductor. If the pressing guide 13 is arranged close to the nip area, the aluminum thin film 20 acts as a counter electrode to the transfer charger 5, so that the transfer charger 5 has the conventional structure shown in FIG. The same function as the pre-charger 14 of this device can be provided. That is, the transfer charger 5 performs pre-charging and transfer, and the pre-charging at that time causes the attraction force between the plain paper 9 and the transfer material transport belt 10. As a result, a drum trap prevention effect can be further improved as compared with the case where the pressing guide 13 having such a configuration is not used.
• the aluminum thin film 20 is not grounded but a potential having a polarity opposite to the polarity of the transfer material transport belt 10 by the transfer charger 5 is applied to the aluminum thin film 20, the above-described preliminary charging is performed. The action can be further enhanced.
• the configuration of the pressing guide 13 is not limited to each of the above-described examples, and it goes without saying that other configurations can be adopted.
• Fig. 14 shows other examples of guide 13 and belt 10 materials. If a material with a small coefficient of friction, such as a Teflon layer R, is provided on the surfaces that come into contact with each other, the frictional static electricity can be reduced. Belt and guide wear due to generation and mutual friction can be prevented
• FIG. 7 is a configuration diagram showing a second embodiment of the present invention in which another fixing additional guide is provided in addition to the pressing guide.
• reference numeral 21 denotes a fixed addition guide, and other components that are the same as those of the above-described embodiment are denoted by the same reference numerals.
• the fixed additional guide 21 is arranged side by side with the pressing guide 13 in an area b shown in FIG. 5, and is fixed so as not to contact the transfer material transport belt 10.
• the gap between the fixed additional guide 21 and the transfer material transport belt 10 is set to be, for example, about 1 mm.
• the plain paper 9 transported on the transfer material transport belt 10 is moved to the nip area as shown in FIG. 27. Before reaching the photosensitive drum 1, the whole surface of the plain paper 9 can be guided to the nip area in a stable state.
• the plain paper 9 before reaching the nip area, the plain paper 9 is transferred to the photosensitive drum 1 by the gap 71 formed between the plain paper 9 and the transfer material transport belt 10 as described above. Since it is possible to prevent the surface from being charged with a polarity opposite to that of the charge 74, the effect of preventing drum trapping can be further improved as compared with the first embodiment.
• a guide # 3 having a structure as shown in FIG. I3 can be used as the pressing guides 13 and Z or the fixed additional guide 21 in this embodiment.
• FIG. 8 shows a pressing guide and an additional guide that can be selectively switched between contact and non-contact states.
• FIG. 10 is a configuration diagram showing a third embodiment of the present invention in which a third embodiment of the present invention is used in combination.
• reference numeral 22 denotes a selective addition guide, and other components that are the same as those of the above-described embodiment are denoted by the same reference numerals.
• the selective additional guide 22 is arranged alongside the pressing guide 13 in the area b shown in FIG. 5, and is in contact with or not in contact with the transfer material transport belt 10.
• the state can be in two states. Further, one side of the selective additional guide 22 is connected to the axis 23, and the signal 26 indicates the type of paper size from the controller 24, and the signal 26 indicates 9.
• the loose motor 25 is driven, The loose motor 25 rotates the shaft 23 connected thereto in the direction of the arrow to selectively put the selective additional guide 22 in a contact state or a non-contact state.
• the selective additional guide 22 is configured so that it does not contact the photoconductor drum 1 during its rotation, so that the photoconductor drum 1 is prevented from being damaged or worn, and is cleaned. It is possible to prevent toner remaining on the photosensitive drum 1 from accumulating in the pressing guide 13 without the toner.
• the apparatus of the present embodiment also assumes that A3, A4, and A5 sizes of plain paper 9 can be used, as in the first and second embodiments.
• Paper 9 In the area a, the pressing guide 13 is functioning permanently.
• the optional additional guide 22 is used to transfer the transfer material when the plain paper 9 is not conveyed and when the A5 size plain paper 9 is conveyed.
• the transfer material belt is moved to a position where it does not contact the belt 10, while the transfer material transport belt is used during the transport of at least the leading edge of the plain paper 9 when transporting A3 and A4 size plain paper 9. It is moved to the position where it touches 10.
• the size of the plain paper 9 being conveyed is determined using the signal 26 indicating the size of the paper in the print data sent from the outside to the relevant apparatus. Based on this, the control device 24 drives the pulse motor 25 to rotate the above-mentioned selective additional guide 22. In addition, a sensor for judging the paper size may be provided in the device, and the control device 24 may be operated based on the detection signal.
• this embodiment also has two areas, an area a in which the plain paper 9 of each size is conveyed in common and an other area b, so that it is optional.
• an additional guide 22 is provided, if the other area b other than the area a is composed of two or more according to the size of the plain paper 9, it is optional according to the number. The number of additional guides 22 may be increased.
• the selective additional guide 22 is transferred to the transfer material transport belt in the area b where the plain paper 9 is not always transported. Even if it is kept in contact with 10, the toner on the transfer material transport belt 10 can easily pass under the guide 13, so the placement of the guide 13
• the present inventors have confirmed through experiments that the amount of toner accumulated in
• the third embodiment is roughly classified into two areas, an area a where the plain paper 9 of each size is conveyed in common, and an area b other than the area.
• Guide 13 is used, and selective addition guide 22 is used in the area b.
• this type of apparatus has a plain paper 9 of each size.
• plain paper 9 of A5 size has only area d
• plain paper 9 of A4 size has only area e
• plain paper 9 of A3 size has all areas. c, d, and e are transported.
• FIG. 10 is a configuration diagram showing a fourth embodiment of the present invention in which the above-described selective addition guides are arranged in the respective regions c, d, and e.
• 27, 28, and 29 are selective guides, that is, additional guides that can switch between contact and non-contact states, and other components that are the same as the components of the above-described embodiment. The same symbols are used.
• the regions c, d, and e correspond to the regions c, d, and e, respectively.
• the selective additional guides 27, 28, and 29 are arranged respectively, and when the old paper 9 of A5 size is conveyed, only the selective additional guide 28 is provided.
• the rotation of these optional additional guides 27, 28, and 29 is controlled in the same manner as in the third embodiment, but in the case of this embodiment, a pulse motor is used.
• the rotation of the main shaft of 25 can be selectively performed by selecting the combination of the gear attached to the main shaft and the gear provided on the connecting shaft of the optional additional guides 27, 28, 29. It is to be communicated to each of the optional additional guides 27, 28, 29. In addition, it is also possible to provide a selective additional guide, for example, only one, and to selectively move it in the width direction of the transport belt.
• FIG. 11 shows the selective addition guide 27, 27 in this embodiment.
• FIG. 9 is a configuration diagram illustrating an example of an image processing device including a control system for operating the operation of the operation of the operation of the control units 28 and 29;
• 30 is a host computer
• 31 is an interface
• 32 is an image signal
• 33 is a paper feed controller
• 34 is an A3 size paper tray
• 35 is an A4 size paper tray
• 36 is an A5 size paper tray
• 37 to 39 are paper feed pulse modes
• 40 is paper Conveyance rollers
• 41 is a pressing guide control device, and other components of the above-described embodiment. The same components as the components are denoted by the same reference numerals.
• the host computer 30 When printing is performed using this image processing apparatus, the host computer 30 must output the image signal 32 to be printed and the size of the paper to be used.
• the signal 26 indicating the type is sent to the interface 31, and the interface 31 sends the image signal 32 to the exposure device 3, and the type of paper size Is sent to the paper feed controller 33.
• the paper feed control device 33 selectively drives one of the paper feed pulse motors 37 to 39 according to the specification of the signal 26, and is adapted to the size of the paper to be used.
• Plain paper 9 is removed from the corresponding trays 34 to 36. The removed plain paper 9 is placed on the transfer material transport belt 10 via the paper transport roller 40.
• the pressing guide control device 41 determines that the size of the plain paper 9 is A3 or A4 based on the signal 26, at least the pressing guide control device 41 During the period in which the leading end portion arrives, the control pulse motor 25 is driven so that only the selective additional guides 27 to 29 or 29 contact the transfer material transport belt 10, and at the same time, Select the desired gear combination to achieve contact. Similarly, when the size of the old paper 9 is determined to be A5, the selective additional guide 28 is transferred to the transfer material at least during the period when the leading end of the plain paper 9 arrives. Control is performed so that the belt contacts the transfer belt 10.
• FIG. 11 is a configuration diagram illustrating another example of an image processing apparatus including a manual control system for operating the image processing apparatus.
• 42 is a copy mode setting panel
• 43 is a light shielding cover
• 44 is a document to be copied
• 45 is glass
• 46 is a light source
• 47 to 52 are reflection mirrors.
• the same components as those of the above-described embodiment are denoted by the same reference numerals.
• This example differs from the previous example in the exposure apparatus, and is of a type in which a scanned image obtained from a document 44 is supplied via reflection mirrors 47 to 52. Since the image forming operation of the example is the same as the previous example, the description of the operation is omitted.
• the copy mode setting panel 42 is used to set the size of the image formed at the time of copying, the paper size, and the like, and the copy mode setting panel 42 is used based on the settings. Since the signal 26 indicating the type of the paper size to be generated is generated, in this example, the same control as in the previous example can be performed using the signal 26.
• each of the optional additional guides 27, 28, and 29 is not always in contact with the transfer material transport belt 10: ⁇ . Since only the adapted selective additional guides 27, 28, and 29 temporarily contact the transfer material transport belt 10, these optional additional guides 27, 28, and 29 There is no need to make the configuration as shown in Fig. I3, and the configuration can be simplified. Optional additional guides 27, 28, 29 are always available Since the transfer belt 10 is not in contact with the transfer material transport belt 10, no toner force is accumulated in a portion where the selective additional guides 27, 28, 29 are arranged.
• control can be performed for the selective additional guide 22 of the third embodiment shown in FIG. 8 by using the control system shown in FIG. 11 or FIG. Is evident.
• the optional additional guides 22, 22, 27, 28, 29 used in the third and fourth embodiments have the shaft 23 connected thereto as a support shaft.
• the selective additional guides 12, 27, 28, 29 are not limited to those having the above-described configuration, but may be replaced as shown in FIG. 15A. An object that can move in, out, or move in a certain direction may be used.
• the photosensitive drum 1 is in contact with the transfer material transport belt 10 even when the belt is not in contact with the transfer material transport belt 10.
• the plain paper 9 can be pressed against the transfer material transport belt 10 near the nip area.
• FIGS. 15B and 15C show modified examples of the guide.
• the guide 53 A during printing shown in FIG. 15B is in contact with the belt 10 and operates normally.
• Belt 10 in the example of Figures 15A and 15B At the time of retraction, the guide 53 A is automatically drawn into the guide support 53 B, so that the tongue is removed from the upper surface of the guide and is placed on the belt as shown. To fall. The dropped toner is cleaned by the belt cleaner 8.
• FIGS. 16 and 17 are a top view and a perspective view showing a configuration of a fifth embodiment of the present invention using a pressing guide having a different configuration.
• a plurality of guide portions 55 are arranged at the lower portion of the guide body 54 to constitute a pressing guide 56 as a whole, and the plurality of guide portions 55 are transferred.
• a predetermined angle 0 with respect to the traveling direction of the material transport belt 10 (however, ⁇ ⁇
• the pressing guide 56 is made of Teflon, and is pressed against the transfer material conveying belt 10 with a constant pressure by a spring 57 as shown in FIG. If the pressing guide 56 is formed in such a shape, at least the leading end of the plain paper 9 transported on the transfer material transport belt 10 has the leading end in the width direction of the transfer material transport belt 10. As a result, the drum trap is prevented from being generated due to the dripping of the leading end of the plain paper 9 as in the above-described embodiments.
• the residual toner is a guide of the pressing guide 56. It moves along the edge of the guide portion 55 as shown by the arrow 58 and does not accumulate in the portion where the pressing guide 56 is arranged. Furthermore, if the pressing guide 56 is made of Teflon, the frictional electrification as described above can be prevented, and the toner can be smoothly moved by improving the releasability of the toner. It can be done.
• the pressing guide 56 is provided at each guide portion on the upstream side in the traveling direction of the transfer material carrying belt 10. It is preferable that the end of 55 is a curved surface, and the radius of curvature of the surface is larger than the thickness of the plain paper 9. Also, in order to more effectively exhibit the drum trap prevention effect, the interval X between the adjacent guide portions 55 is set to be equal to the widthwise guide portion 29 on the transfer material transport belt 10. It is preferable to select each guide portion 55 to be uniformly smaller than the length y of the transfer material conveying belt 10 in the width direction of the transfer material conveying belt 10.
• the Teflon guide portion 55 will be worn, especially where the plain paper 9 passes a lot.
• the degree of abrasion differs between a few places and the pressing pressure can vary from place to place, so as in the fourth embodiment,
• the pressing guide 56 may be divided, and each of the divided guides may be pressed against the transfer material conveying belt 10 at a constant pressure by the spring 57. At this time, even if the amount of wear differs for each of the divided pressing guides 56, there is no variation in the pressing pressure, and the drum trap prevention effect can be effectively exhibited. Can be.
• FIG. 19 is a configuration diagram showing a second example of the pressing guide in which the arrangement of the guide portions is different.
• 58 is a guide body
• 59 and 60 are guide portions
• other components that are the same as the components of the above-described embodiment are denoted by the same reference numerals.
• a plurality of pairs of guides 59 and 60 are arranged at the lower part of the guide body 58 to constitute a pressing guide 61 as a whole.
• the portion 59 has a predetermined angle 0 (90 degrees) with respect to the traveling direction of the transfer material transport belt I 0, and the other plurality of guide portions 60 have the transfer material 60.
• the transfer belt 10 is provided so as to have an angle 10 opposite to the above-mentioned angle 0 with respect to the traveling direction of the transfer belt 10, so that the transfer belt 10 is almost entirely covered in the width direction.
• Guide sections 59, 60 so that they touch each other. It's done.
• the pressing guide 61 is also pressed against the transfer material conveying belt 10 by the spring 57 at a constant pressure.
• the transfer material conveying belt 10 and the plain paper 9 that are in contact with the pressing guide 61 are perpendicular to the conveying direction of the plain paper 9.
• Directional force that is, tension to flatten the transfer material transport belt 10 and the plain paper 9 works, and has the secondary effect of preventing the occurrence of shear on the plain paper 9. .
• the plain paper 9 has two A force of the same magnitude acts in the direction, and it is possible to maximize the effect.
• the pressing guide 61 is made of Teflon, it goes without saying that the toner rejection effect as in the above-described example can be obtained.
• the pressing guide 61 can be divided in the same manner as in the previous example.
• FIG. 20 is a configuration diagram showing a third example of the pressing guide in which the arrangement of the guide portions is further different.
• reference numeral 63 denotes a guide body
• reference numeral 64 denotes a guide portion
• other components which are the same as those of the above-described embodiment are denoted by the same reference numerals.
• a plurality of triangular guide portions 64 are arranged at the lower portion of the guide body 63 to constitute a pressing guide 65 as a whole.
• the plurality of triangular guides 64 are configured such that one of the guides 64 comes into contact with almost the entire area of the transfer material conveying belt 10 in the width direction, and the pressing guide 6 5 is also pressed against the transfer material conveying belt 10 by a spring 57 at a constant pressure as shown in FIG.
• the same drum trap prevention effect as in the above-described example can be obtained, and the residual toner is also transferred from the transfer material transport belt 10 as indicated by an arrow 86 in the same manner as in the above-described example. It moves and does not accumulate in the placement area of the pressing guide 65. Further, also in this example, if the pressing guide 65 is made of Teflon, the toner rejection effect as in the above-described example can be obtained.
• FIG. 21 shows a sixth embodiment of the present invention in which the projecting means is temporarily operated before the transfer of the plain paper 9 as the transfer material to remove the toner accumulated in the pressing guide.
• FIG. 3 is a configuration diagram showing an example of FIG.
• 6 7 is a rotating roller that constitutes the projecting means
• Reference numeral 68 denotes a pressing guide made of Myrafilm
• reference numeral 69 denotes a rotary roller control device
• other components that are the same as those of the above-described embodiment are denoted by the same reference numerals. I have.
• a rotary port ⁇ 67 having a convex portion is disposed at a lower position of the transfer material transport belt 10 on which the pressing guide 68 is disposed.
• the rotation of 67 is controlled by a rotating roller control device 69.
• the rotating roller control device 69 shifts and fixes the convex portion of the rotating roller 67 to a position where the transfer material conveying belt 10 is not pushed up while the plain paper 9 is being conveyed, and if the plain paper 9 is not conveyed. Or when the gap of the conveyance of the plain paper 9 reaches the pressing position of the pressing guide 68, the rotating roller 67 is rotated as shown in the figure, and the transfer material conveying belt 10 is protruded at the convex portion. Is deformed extremely to remove the toner accumulated between the pressing guide 68 and the transfer material conveying belt 10. At this time, in order not to damage the transfer material transport belt 10, it is desirable that the peripheral speed be the same as the traveling speed of the transfer material transport belt 10.
• the effect of pressing the plain paper 9 by the pressing guide 68 provides not only the effect of preventing drum trapping but also the use of the rotating roller 67 having a convex portion.
• the toner accumulated between the pressing guide 68 and the transfer material transport belt 10 is removed by the toner removing operation, and the toner is carried away by the transfer material transport belt 10 and the belt clear. Can be removed by the tool. Further, the same effect can be obtained even if the cross-sectional shape is an ellipse or an ellipse as the shape of the convex portion.
• FIG. 9 is a configuration diagram showing another example of the projecting means using a transfer material transport belt 10 having a convex portion 70 on a part of its surface instead of the rotary roller 67. In this example, components other than the transfer material transport belt 10 are not shown.
• reference numeral 70 denotes a convex portion provided on a part of the surface of the transfer material conveying belt 10, and other components which are the same as those in the above-described example are denoted by the same reference numerals. are doing.
• the toner accumulated between the pressing guide (not shown) and the transfer material transfer belt 10 is removed by the same timing and action as in the above-described example, and the transfer material is removed. This prevents toner from accumulating on the conveyor belt 10.
• the height of the convex portion 70 is set to several mm or less to smoothly move the transfer material transport belt 10 and to prevent the photosensitive drum 1 from being damaged. Fluororesin was deposited on the belt 10 surface. Also, in order to prevent the plain paper 9 from climbing over the projection 70 and reaching the transfer point and causing transfer failure, the conveyance of the plain paper 9 is set so that the projection 70 is located in the gap of the conveyance of the plain paper 9. Timing control is the same as in the previous example.
• FIG. 39 An outline of the overall configuration of the electrophotographic recording device described above is as shown in FIG. 39, for example.
• the electrophotographic recording apparatus includes a photosensitive drum 201, a charging device 202, an exposing device 203, a developing device 204, a transfer device 205, and a recording paper 2 6, a fixing unit 2007, an erase lamp 208, and a cleaner 209 power.
• the photoreceptor drum 201 is rotated at a constant speed by a driving device (not shown), and first, this surface is uniformly charged by a negative charge in the charger 202. . Next, the surface is exposed in an exposure device 203 including a laser light emitter, a polygon mirror, and the like, and an electrostatic latent image is formed thereon. Next, the electrostatic latent image is formed by the negatively charged toner adhered to the developing device 204, and a visible image corresponding to the electrostatic latent image is formed on the surface. You. The visible image is transferred to the nip area having the transfer device 205, and the recording paper conveyed to the recording paper conveyance body (not shown) is provided at this time.
• the recording paper 206 arrives, and the recording paper 206 is charged with a plastic charge in the transfer unit 205 together with the recording paper carrier, so the recording paper 206 is placed on the recording paper 206 in this nip area.
• the toner is attached to transfer the visible image.
• the recording paper 206 onto which the visible image has been transferred is to which toner is fixed in a fixing device 2007 and predetermined recording is performed.
• the toner remaining on the surface of the photosensitive drum 201 is removed by an erase lamp 208 and a cleaner 209, and the above-described process is repeated. Is what is returned.
• FIG. 28 is a main part configuration diagram showing a seventh embodiment of the electrophotographic recording apparatus according to the present invention, and particularly shows a peripheral portion of the transfer device 205 shown in FIG. is there.
• 101 is a drum
• 102 is a photoreceptor
• 103 is a toner
• 104 is a recording sheet
• 105 is a recording sheet
• 105 is a burr at the leading end of 104
• 106 is a recording sheet.
• Conveyor 107 is a gap
• 108 is a pressing roller
• 109 is a drive roller
• 110 is a register roller
• 111 is a paper position detection sensor
• 112 is a collocator.
• Jar 113 are colony wires
• 114 is a constant current source
• 115 is a control circuit
• 115 is a paper sensor
• 117 is a paper sensor
• 117 is a humidity sensor
• 118 is It is a measurement circuit.
• the corona charger 1 1 3 of the corona charger 1 1 2 receives the current It from the constant current source 1 1 4 and generates a charge as shown in the recording paper transport 1 106. Let it. Paper position detection sensor 1 1 1 located near the register controller 110 Detects the leading edge of the recording paper 104 supplied from the register roller 110, and sends the detection output V s obtained here to the control circuit.
• the paper quality sensor 116 detects the type of recording paper 104, for example, the thickness, the difference between high quality paper and recycled paper, and the humidity sensor 117 detects the surrounding humidity.
• the recording paper transport member 106 has a thickness of 500 ⁇ m in thickness, a rubber rubber belt having a fluorine-based coating formed on both surfaces. Three layers of about 650 m are used.
• the recording paper 104 is supplied via the power register roller 110, and when the leading end is detected by the paper position detection sensor 111, the detection signal V s is supplied to the control circuit 111. Supplied to Upon receiving this signal Vs, the control circuit 115 sets the timing of the current It applied to the core ⁇ wires 113 and the value of the current It.
• the control circuit 115 sets the timing of the current It applied to the core ⁇ wires 113 and the value of the current It.
• the control circuit 115 Generates an electric current It, and starts an operation of giving the leading end charge amount Q 1 to the recording paper transport body 106 as described below.
• the control circuit 115 when the leading end of the recording paper 104 is conveyed to the exit portion Lno of the nip area, the control circuit 115, as shown in FIG. t, and the normal transfer operation Move to work.
• the moving speed of the recording paper transport body 106 is U b
• the time T c at which the leading end of the recording paper 104 receives the electric charge from the colony roller 112 is , T c ⁇ (L no — L a) ZU b.
• the average value of the current flowing into the recording paper transporting body 106 is I 1 V out of the current I t having a magnitude I: generated by the control circuit 115
• the transfer characteristics are determined by the current flowing into the recording paper transport.
• the above example is for the case where the current It supplied to the corona charger 112 is changed in two stages, II and Im, as shown in FIG. 29. Further, when the leading edge of the recording paper 104 is transported to the middle point of the colony charger 112, the control circuit 115 outputs the magnitude force I! The current I t I Ri to generate a current I t of large value I 2, then, when the leading end of the recording sheet 1 0 4 is conveyed to the outlet portion L no of Knitting flop area, as before the size Therefore, it is possible to generate a current It of Im, that is, to change the current into three stages.
• control circuit 1 1 5 occurs magnitude Saga electrodeposition I 2 Assuming that the average value of the current flowing into the recording paper transport 106 out of the current It is I 2 v, the recording paper transport 1 corresponding to the leading end of the recording paper 104 at this time
• the initial charge Q 1 2 given to 06 is
• the recording paper 104 becomes the photosensitive member 102. It does not wrap around, and the drum trap phenomenon does not occur.
• the drum trap phenomenon depends on the type of recording paper 104 or the surrounding environment, especially humidity, so when the type of recording paper 104 is changed, When the humidity changes significantly, etc., the detection output from the paper sensor 116 and the humidity sensor 117 is appropriately processed by the measurement circuit 118, and then supplied to the control circuit 115. In addition, the magnitude of the current It supplied to the colony charger 111 is controlled.
• FIG. 30 is a block diagram showing the detailed configuration of the constant current source 114 and the control circuit 115 used in the embodiment of FIG.
• 114 a is a low current source
• 114 b is a high current source
• other components that are the same as those shown in FIG. 28 are given the same reference numerals. .
• the constant current source 114 is composed of a low current source 114a generating a small current and a high current source 114b generating a large current. And the high current source 1 14 b have a control signal V s 1.
• V sh is supplied.
• each signal is shown in negative logic.
• V s becomes the Low level
• a control signal V s 1 which becomes the L 0 W level from the time t 3 after the elapse of the time T s to the time t 4 is generated, and within the control signal V s 1 application period.
• the low current source 114a generates a current I t with a small value I i.
• the control circuit 1 15 changes time t 4 From to time t 5 generates a control signal V sh becomes L ow level, high current source 1 1 4 b within the application period of the control signal V sh This generates a current I t of large value I m.
• T s is the time from when the leading edge of the recording paper 104 is detected by the paper position detection sensor 111 to when it reaches the inlet end La of the cara corona charger 111.
• Te is the time from when the leading edge of the recording paper 104 reaches the entrance end L a of the corona charger 112 to the exit end L n0 of the nip area.
• T r is the time during which the transfer current of a large value Im flows
• T q is the one recording paper 104 and the next recording paper 104 being conveyed, respectively. It is time between.
• FIG. 31B shows a small value I! Between one recording paper 104 and the next recording paper 104.
• the timing of the control signal Vsh generated by the control circuit 115 is the same as that of Vs1 in FIG. 31A. in a while, the control signal V s 1 is 31 times t 4 force Remind as in B, until et time t 5 is L 0 w leveled FIG.
• the transfer speed of the recording paper transport body 106 is 1 Oips
• the width of the corona chargeer 112 is 20 mm
• the width of the nip area (this is (Ln0— L b)> 10) is set to 10 mm
• the current It shown in FIG. 4A is supplied under the environmental conditions of 20 ° C.
• the conduction current I of the colony charger 112 is 25 to 1008, and Im is 300 uA
• the leading edge of the recording paper 104 The current flowing into the paper section is 5 to 20 A, and the current flowing into the area excluding the leading edge of the recording paper 104 is about 50 ⁇ A, which is about 10 mm from the leading edge of the recording paper 104.
• the transfer efficiency of the region within the range is 60 to 80%.
• Figure 33 shows the optical reflection density of an image with the transfer efficiency as a parameter. According to the figure, it can be seen that the optical reflection density is almost saturated when the transfer efficiency is 60% or more, even if the toner weight of the paper increases. Therefore, according to the present invention, high-quality recording is performed. You can do that. At the same time, it was confirmed that the recording paper 104 did not wrap around the photoconductor 102.
• the colony charge is started.
• I m about 300 A
• the transfer efficiency of the area from the leading edge of recording paper 104 to about 3 mm was 60 to 80. %.
• the transfer efficiency of the portion of the recording paper 104 other than the above area was about 80% or more, and there was no particular problem in image quality. Further, in this case also, it was confirmed that no wrapping of the recording paper 104 around the photoconductor 102 occurred.
• the temperature was changed to 20 ° (40% RH, and the small value I was set to 200 A and the large value Im was set to 300 A. No winding of the photoconductor 104 on the photoconductor 102 occurred, and a transfer efficiency of about 80% or more was obtained over the entire recording paper 104.
• FIG. 32 is a configuration diagram showing an eighth embodiment of the electrophotographic recording apparatus according to the present invention.
• reference numeral 119 denotes a conductive bias roller which presses the recording paper transport body 106 toward the photosensitive body 102
• reference numeral 120 denotes a pressure applying means
• reference numeral 121 denotes a voltage source.
• Figure 2 The same components as those shown in Fig. 8 are denoted by the same reference numerals.
• the conductive bias roller 119 is a metal roller or a metal roller having a low resistance film formed on the surface thereof, and is rotated by the action of the pressure applying means 120 while rotating the recording paper transporting member.
• a voltage applied from the voltage source 121 causes a voltage to be applied to the recording paper transport body 106.
• a voltage is applied to the recording paper transport 106 via the conductive bias roller 119, and a positive charge is generated in the recording paper transport 106 by the voltage.
• the means for generating charges is different from that of the seventh embodiment, the other points are almost the same as those of the seventh embodiment.
• FIG. 34 shows the temporal change of the voltage applied to the bias roller 1 19.
• the control circuit 1 I5 starts the voltage supply 1 2 1 Control the small value V! Is supplied to the bias roller 1 19, and when the tip reaches the exit point L n0 of the nip area, the control circuit 115 supplies the large value V m required for normal transfer. Is supplied to the bias roller 1 19.
• the voltage of the small value V When the gap 105 is formed between the recording paper 104 at the leading end and the recording paper carrier 106, the recording paper carrier Even if the voltage of this small value V, is applied to 106, the value is selected such that no discharge occurs in the gap 107, in other words, the small value
• the small value V is selected so that the amount of charge Q generated in the recording paper transport body 106 by the supply of V, is not more than the above-mentioned amount of charge Qb.
• the charge amount Q generated by the small value V is selected so that the transfer efficiency is at least 60% or more.
• the recording paper 104 is not wrapped around the photoconductor 102, and the transferred image at the leading end of the recording paper 104 is deteriorated. It does not work.
• FIG. 35 is a configuration diagram showing a ninth embodiment of the electrophotographic recording apparatus according to the present invention.
• reference numeral 122 denotes a current source
• reference numeral 123 denotes a shielded inflow current detection circuit
• other components that are the same as those shown in FIG. 28 have the same reference numerals. .
• the shield inflow current detection circuit 1 2 3 includes the current I t flowing through the corona wire 1 1 3 of the corona junction 1 1 2, and
• the current source 122 changes the output current value It based on the detection result of the shield inflow current detection circuit 123. That is, a part of the current It supplied from the current source I 22 to the corona charger 113 of the corona charger 112 flows into the recording paper transport 106 and a part of the current I t. Although supplied as b, the remainder flows as the shield current Is into the shield of the corona shunter 112.
• the inflow current Ib is not constant.
• the value of the shield current I s is detected by the shield inflow current detection circuit 123 and when the value of the shield current I s changes, the polarity of the change and The amount of the signal is fed back to the current source 122, and the current It is made variable according to the amount of the feedback. As a result, the inflow current lb is reduced. It can be constant.
• the seventh embodiment since the current Ib flowing into the recording paper transport 106 directly related to the amount of electric charge applied to the recording paper transport 106 is controlled, the seventh embodiment is different from that of the seventh embodiment. Like the above, it is possible to perform a control with higher precision than controlling the transfer current It of the corona chargeer 112.
• the pressing guide or the pressing guide and the additional guide which are means for preventing wrapping, are arranged in the transfer material transporting means, at least a part or a part of the leading end of the transfer material is provided.
• the entire guide can be pressed against the transfer material conveying means by the guide, and it is possible to prevent the transfer material from being wound around the image carrier (drum trap).
• Prevention means since the means for removing the image forming medium (toner) accumulated in the portion on the transfer material transporting means where the transfer material is relatively infrequently transported is arranged, Prevention means, in particular, it is possible to effectively remove the image forming medium (toner) accumulated in the portion where the additional guide is disposed, and to prevent generation of stains generated at the leading end of the transfer material during copying. it can.
• the recording paper transporting body corresponding to the leading end of the recording paper is provided with a charge amount Q j having the same polarity as the transfer charge, which is smaller than the transfer charge amount Q m.
• the recording paper may be wrapped around the photoconductor, so-called drum trap phenomenon. This has the effect of preventing occurrence.
• the charge amount Q j is insufficient for normal transfer.
• the transfer electric field acts between the surface of the photoreceptor and the recording paper transporter, and the surface of the photoreceptor also acts on the leading end of the recording paper. This has the effect of transferring a visible image.
• a transfer charge sufficient to perform the transfer is given to a portion other than the leading end portion of the recording paper, so that clear transfer can be performed as before.
• the so-called drum trap phenomenon in which the transferred image is not deteriorated at the leading end portion of the recording paper and the recording paper is not wound around the photoconductor, occurs.

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• Electrostatic Charge, Transfer And Separation In Electrography (AREA)

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• 1992
  • 1992-04-10 DE DE19924291112 patent/DE4291112T1/de active Pending
  • 1992-04-10 WO PCT/JP1992/000452 patent/WO1992018912A1/ja active Application Filing
  • 1992-04-10 DE DE4291112A patent/DE4291112C2/de not_active Expired - Fee Related

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