EP0552745A2 - Elektrophotographisches Druckgerät - Google Patents

Elektrophotographisches Druckgerät Download PDF

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Publication number
EP0552745A2
EP0552745A2 EP93100821A EP93100821A EP0552745A2 EP 0552745 A2 EP0552745 A2 EP 0552745A2 EP 93100821 A EP93100821 A EP 93100821A EP 93100821 A EP93100821 A EP 93100821A EP 0552745 A2 EP0552745 A2 EP 0552745A2
Authority
EP
European Patent Office
Prior art keywords
recording material
toner
printing machine
moving means
electrophotographic printing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP93100821A
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English (en)
French (fr)
Other versions
EP0552745B1 (de
EP0552745A3 (en
Inventor
Tomohiro Oikawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sharp Corp
Original Assignee
Sharp Corp
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Filing date
Publication date
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Publication of EP0552745A2 publication Critical patent/EP0552745A2/de
Publication of EP0552745A3 publication Critical patent/EP0552745A3/en
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Publication of EP0552745B1 publication Critical patent/EP0552745B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/34—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the powder image is formed directly on the recording material, e.g. by using a liquid toner
    • G03G15/344—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the powder image is formed directly on the recording material, e.g. by using a liquid toner by selectively transferring the powder to the recording medium, e.g. by using a LED array
    • 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
    • G03G15/1605—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 at least one intermediate support
    • 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
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/24—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 whereby at least two steps are performed simultaneously

Definitions

  • the present invention relates to an electrophotographic printing machine which forms an image on a recording material by forming a toner image on a surface of a photoreceptor and then transferring and fixing the toner image onto the recording material.
  • an electrophotographic printer using the Carson process includes a charger 52 such as a corona discharger, an exposure unit 53, a developer unit 54, a transfer unit 55 such as a corona discharger, and a cleaner 56. These devices are disposed in this sequence on the periphery of a photoreceptor drum 31 having a photoconductive layer formed on the surface thereof.
  • the surface of the photoreceptor drum 31 is uniformly charged by the charger 52 in a dark place.
  • an image on an original document is projected onto the surface of the photoreceptor drum 31 by the exposure unit 53 to remove the electric charges on the portion exposed to light.
  • an electrostatic latent image is formed on the surface of the photoreceptor drum 31.
  • toner 39 which has been charged to a polarity opposite to the electric charges on the photoreceptor drum 31, is caused to adhere to the electrostatic latent image to form a visible image.
  • a recording material 41 fed by a feed roller 39 is sent between the photoreceptor drum 31 carrying the toner image on its surface and the transfer unit 55 by transport rollers 42, thereby transferring the toner image to the recording material 41.
  • the transport rollers 42 feed the recording material 41 carrying thereon the transferred toner image through a transport guide plate 36 to a fusing unit 45 having a pressure roller 37 and an in-plane heater 40.
  • a fusing unit 45 having a pressure roller 37 and an in-plane heater 40.
  • the toner image is heated by the heater 40, the toner image is fixed to the recording material 41.
  • the recording material 41 with the toner image fixed thereon is discharged outside of the printer by discharge rollers 43.
  • a sheet 44 which is easily separated from the toner 35 is sandwiched between the recording material 41 and the heater 40.
  • the sheet 44 is wound around a roller 57, and unrolled from the roller 57 and then wound around a roller 58 in accordance with a need.
  • a heat roller system is proposed.
  • a fusing unit 59 having a heater 46a therein, a heat roller 46 made from a material which is easily separated form the toner 35, and a pressure roller 47 is used for fixing.
  • the transport of the recording material 41 to the fusing unit 59 is executed by the transport rollers 42 and a transport guide plate 36.
  • the transport rollers 42 apply a transport force to the recording material 41, while the transport guide plate 36 guides the recording material 41 to the fusing unit 59.
  • the transport rollers 42 apply the transport force only to the rear edge of the recording material 41. This causes the leading edge of the recording material 41 fed past the transport guide plate 36 to be curled, resulting in unstable transport of the recording material 41. Moreover, when the transport force is applied only to a certain portion of the recording material 41, the recording material 41 tends to be creased. Therefore, the configuration induces a distorted image on the recording material 41.
  • the fusing unit 59 needs to provide a transport force sufficient to achieve stable transport of the recording material 41.
  • an endless transport belt 48 is proposed to be installed between the transport roller 42 and the fusing unit 59 as illustrated in Fig. 10.
  • the transport force is not effected on the leading edge of the recording paper 41 just before the recording material 41 reaches the fusing unit 59, preventing the recording material 41 from reaching the fusing unit 59 in a stable manner. It is thus difficult to surely prevent the distorted image from being formed on the recording material 41.
  • the electrophotographic printing machine of the present invention includes: photoreceptor means having a photoconductive layer; toner-image forming means for forming a toner image on a surface of the photoreceptor means; moving means which moves while making contact with the surface of the photoreceptor means, the moving means having at least a dielectric surface in contact with the photoreceptor means; transfer means for transferring the toner image formed on the surface of the photoreceptor means to the moving means; transfer and fusing means, mounted in contact with the moving means, for transferring the toner image on the moving means to a recording material and fixing it thereon; and recording material transport means for transporting the recording material onto the moving means moving toward the transfer and fusing means.
  • the toner image formed on the surface of the photoreceptor means by the toner-image forming means is temporally transferred to the moving means by the transfer means, and is then transferred to and fixed on the recording material by the transfer and fusing means.
  • the recording material is first transported onto the moving means moving toward the transfer and fusing means by the recording material transport means and is then transported to the transfer and fusing means by the moving means.
  • the moving means stably applies a continuous transport force to the recording material evenly until the recording material reaches the transfer and fusing means. Consequently, the recording material is stably transported to the transfer and fusing means. Accordingly, the electrophotographic printing machine is capable of fixing the toner image on the recording material without distortion.
  • the electrophotographic printing machine of the present invention may have, in addition to the above-mentioned structure, a support member for supporting the moving means to be flat, the support member being disposed underneath the moving means at a contacting position of the moving means and the recording material so that the moving means slides over the support member.
  • the surface of the moving means onto which the recording material has been transported by the recording material transport means is always supported to be flat by the support member, it is possible to reduce the change in the area of the contact region of the recording material and the moving means. Namely, if the support member does not exists, when the leading edge of the recording material comes into contact with the moving means, the surface of the moving means undulates, causing a change in the area of the contact region. However, such a problem is solved by the installation of the support member. Moreover, since the moving means is charged when the moving means slides along the support member, the adhesiveness between the recording material and the moving means is intensified.
  • the transport force is applied to the recording material in a highly stable manner by the moving means, and the recording material is accurately transported to the transfer and fusing means.
  • the electrophotographic printing machine with this configuration achieves more stable image formation.
  • Figs. 1 through 7 show the present invention in detail.
  • Fig. 1 is a view showing the structure of the essential components of an electrophotographic printing machine according to a first embodiment of the present invention.
  • Fig. 2 is a schematic view showing the structure of the electrophotographic printing machine of Fig. 1.
  • Fig. 3 is an enlarged cross sectional view of the essential components, explaining the principle of the formation of a toner image in the electrophotographic printing machine.
  • Fig. 4 is an enlarged cross sectional view of the essential components, explaining a change in the state of the essential components when an exposure is conducted in the state of Fig. 3.
  • Fig. 5 is an enlarged cross sectional view of the essential components, explaining a change in the state of an exposed portion of the photoreceptor drum when it is moved away from toner held by the development sleeve.
  • Figs. 6 is a schematic view showing the structure of an electrophotographic printing machine according to a second embodiment of the present invention.
  • Fig. 7 shows a view showing the essential structure of the electrophotographic printing machine of Fig. 6.
  • Figs. 8 through 10 show a prior art.
  • Figs. 8 is a schematic view showing the structure of a conventional electrophotographic printing machine.
  • Fig. 9 is a view showing the structure of essential components of another conventional electrophotographic printing machine.
  • Figs. 10 is a view showing the structure of essential components of still another conventional electrophotographic printing machine.
  • an electrophotographic printing machine of this embodiment is provided with a cylindrical photoreceptor drum 1 (photoreceptor means) that is rotatable in a clockwise direction within the machine.
  • a developer sleeve 3a is located on the right side of the photoreceptor drum 1 in which an exposure unit 2 (toner-image forming means, and exposure means) is installed.
  • a transfer belt 22 (moving means) is placed above and in contact with the photoreceptor drum 1 so that it moves over the surface of the photoreceptor drum 1.
  • the photoreceptor drum 1 is constituted by a cylindrical transparent base 103 having a transparent electrically conductive layer 102 and a photoconductive layer 101 made of photoconductive material, laminated in this order on the surface thereof.
  • an In2O3 layer with a thickness of about 0.5 ⁇ m formed by sputtering In2O3 is used as the transparent electrically conductive layer 102.
  • an amorphous Si layer with a thickness of about 3 ⁇ m is formed.
  • the transparent electrically conductive layer 102 is not limited to the In2O3 layer, and, for example, an SnO2 layer is preferable for use.
  • the photoconductive layer 101 is not limited to the amorphous Si layer, and, for example, an Se layer, a ZnO layer or a CdS layer can also be used.
  • the developer 3 includes a toner vessel 8 for storing electrically conductive magnetic toner 5 as a developer; a mixing roller 7 for mixing the toner 5, the mixing roller 7 being pivotally mounted in the toner vessel 8; a substantially cylindrical developer sleeve 3a (toner-image forming means, and toner holding means) which is placed at an opening 8a of the toner vessel 8 so that it faces the photoreceptor drum 1 and a doctor blade 6 fixed under the developer sleeve 3a at the opening 8a.
  • a toner vessel 8 for storing electrically conductive magnetic toner 5 as a developer
  • a mixing roller 7 for mixing the toner 5, the mixing roller 7 being pivotally mounted in the toner vessel 8
  • a substantially cylindrical developer sleeve 3a toner-image forming means, and toner holding means
  • the developer sleeve 3a extends in an axis direction of the photoreceptor drum 1 and has therein a substantially cylindrical magnetic roller 4 mounted around the axis of the developer sleeve 3a.
  • the magnetic roller 4 has N polarity magnets and S polarity magnets that are alternately disposed along the internal surface of the developer sleeve 3a.
  • the developer sleeve 3a is made of a non-magnetic electrically conductive material such as aluminum or martensite series stainless steel.
  • the developer sleeve 3a holds the toner 5 on the surface thereof with the use of an alternating field generated by the counterclockwise rotation of the magnetic roller 4 and transports the toner 5 in the reverse direction, i.e., a clockwise direction.
  • the doctor blade 6 adjusts the amount of the toner 5 to be held on the surface of the developer sleeve 3a and transported in the clockwise direction to a predetermined amount.
  • the toner 5 is produced in the following manner. First, powdered magnetic material such as powdered iron or ferrite and powder color such as carbon black are mixed into a resin made from styrene-acrylic copolymer by kneading. The mixture is then ground into particles ranging from several ⁇ m to several tens ⁇ m, to obtain the toner 5. In order to have the toner 5 with high electric conductivity, it is desirable to use an electrically conductive color.
  • the exposure unit 2 includes a light emitting diode (LED) array wherein a plurality of lens having a short focal distance and LEDs are combined.
  • the exposure unit 2 projects a light beam toward the developer 3 in response to an image pattern signal from an exposure control unit (not shown). As illustrated in Fig. 4, the light beam projected is converged on the photoconductive layer 101 through the transparent base 103 and the transparent electrically conductive layer 102 of the photoreceptor drum 1.
  • a power supply 29 (toner-image forming means, and voltage application means) applies a predetermined voltage to the transparent electrically conductive layer 102 and the developer sleeve 3a.
  • the transfer belt 22 is produced by shaping into an endless belt a film material including mainly polyimide having good dielectric and heat-resistant properties, and mechanical strength.
  • the transfer belt 22 is attached around a transfer roller 14, a heater 15 (to be described later) and a tension roller 21.
  • the transfer roller 14 is made of an electrically conductive resilient member and mounted above the photoreceptor drum 1.
  • the heater 15 is placed on the left side and slightly upper side of the transfer roller 14.
  • the tension roller 21 is located on the left side and slightly lower side of the heater 15.
  • the transfer belt 22 is sandwiched between the photoreceptor drum 1 and the transfer roller 14.
  • a film-shaped polyimide resin is used in this embodiment.
  • the material is not particularly limited to this material, and it is possible to use other material if that film is dielectric, has suitable mechanical strength, and is formed into an endless belt.
  • polyamide resin is a suitable material for the transfer belt 22.
  • a material for the transfer belt 22 needs to meet the following three requirements.
  • the surface on which the toner 5 is transferred i.e., the surface in contact with the photoreceptor drum 1.
  • the material is resistant to heat applied by the heater 15.
  • the material is separated from the toner 5 fused by the heat more easily in comparison to the recording material P. It is especially desirable to form the transfer belt 22 by a metal belt having a dielectric layer formed on its surface in contact with the photoreceptor drum 1.
  • An electric cast nickel belt is preferable for the metal belt, and the dielectric layer is preferably formed by coating the surface of the metal belt with fluorocarbon polymers.
  • a desirable thickness is in the range of about 10 ⁇ m to 200 ⁇ m.
  • the transfer belt 22 by making the transfer belt 22 with a rough surface, the image with appropriate gloss is formed on the recording material P. This causes friction between the recording material P transported by the transfer belt 22 and the surface of the transfer belt 22, ensuring proper transport of the recording material P by the transfer belt 22.
  • the heater 15 is provided for heat-fusing the toner 5 transferred to the surface of the transfer belt 22.
  • the heater 15 is a ceramic heater produced by printing a plane-shaped Mo series resistance heater 16 on an alumina ceramic substrate and laminating a glass coat thereon by printing. Further, the heater 15 is designed such that the temperature of the heating surface thereof is rapidly raised up to a predetermined heating temperature by conducting electricity through the resistance heater 16. The heater 15 is disposed such that the heating surface thereof is in direct contact with the inner surface of the transfer belt 22.
  • a pressure roller 17 Disposed above the heater 15 is a pressure roller 17 which rotates while pressing the heater 15 through the transfer belt 22.
  • the pressure roller 17 is arranged so as to sandwich the recording material P fed between opposing transport guide plates 13 (recording material transport means, and guide members, to be described later) at the pressurized portion between the transfer belt 22 and the pressure roller 17.
  • the electrophotographic printing machine of this embodiment has a cooling fan 24, located under the transfer belt 22, for cooling down the transfer belt 22 which has been heated by the heater 15, a main motor 23 as a drive source of the machine, and discharge means 25 for discharging the recording material P from the machine.
  • the transport guide plates 13 are located above the photoreceptor drum 1, developer 3, and the transfer belt 22 to form a transport path running almost horizontally from register rollers 12, to be described later, to the transfer belt 22.
  • an angle ⁇ formed by the transfer belt 22, which runs upwardly from the transfer roller 14 to the heater 15, and the lower transport guide plate 13 is arranged 15° in this embodiment.
  • the angle ⁇ is not limited to 15°.
  • the angle ⁇ is smaller than 0°, i.e, takes a negative value, installation of other members, for example, of the photoreceptor drum 1 becomes difficult.
  • the angle ⁇ exceeds 40°, a force exerted by the weight of the recording material P becomes stronger than frictional resistance between the transfer belt 22 and the recording material P. Therefore, there is a possibility that the recording material P slides down the transfer belt 22, causing instability in transporting the recording material P to the heater 15.
  • Such a range of the angle ⁇ is determined through an experiment.
  • the angle ⁇ was set within the following four ranges, 0° ⁇ ⁇ ⁇ 20°, 20° ⁇ ⁇ ⁇ 40°, 40° ⁇ ⁇ ⁇ 60°, and 60° ⁇ ⁇ , and an image was formed on 100 sheets of recording material P, respectively, to observe the occurrence of crease and jam of the recording material P.
  • Table 1 gives the results. When the angle ⁇ was set within the range 20° ⁇ ⁇ ⁇ 40°, jam was not observed, and the recording material P got a crease to a degree that did not practically affect the operation. When the angle ⁇ was set within the range 0° ⁇ ⁇ ⁇ 20°, jam and crease were not observed, forming an image of favorable quality. TABLE 1 0° ⁇ 20° 20° ⁇ 40° 40° ⁇ 60° 60° ⁇ 40° crease 0/100 3/100 7/100 7/100 jam 0/100 0/100 3/100 3/100 3/100
  • ⁇ is indicated by degree
  • occurrence of crease or jam is shown by a ratio of the number of sheets got a crease or jammed to the total number of sheets tested.
  • the electrophotographic printing machine includes a feed actuator 10, feed rollers 9, the register rollers 12 in the course of the transport path formed by the transport guide plates 13, and a feed solenoid 11 for controlling the rotation of the register rollers 12.
  • the discharge means 25 is located on the left side of the pressurized portion between the transfer belt 22 and the pressure roller 17.
  • the discharge means 25 includes a discharge guide plates 19, a discharge actuator 18, and transport rollers 20.
  • the discharge guide plates 19 form a discharge path linking the pressurized portion and a recording material discharge opening, not shown.
  • the discharge actuator 18 is placed in the vicinity of the pressurized portion.
  • the transport rollers 20 are placed near the end of the discharge guide plates 19.
  • a sheet of recording material P is fed into the machine by the recording material supply means (not shown) through a recording material supply opening.
  • a feed detection switch not shown, detects the feeding of the recording material P and then transmits a feed detection signal to the main motor 23. Upon receiving the signal, the main mother 23 starts rotating.
  • the rotation of the main motor 23 is transmitted to the feed rollers 9 through a rotation transmission mechanism (not shown), thereby rotating the feed rollers 9.
  • the rotation of the feed rollers 9 transports the recording material P to the register rollers 12.
  • the recording material P transported to the register rollers 12 is temporarily stopped when the register rollers 12 stop rotating under the control of the feed solenoid 11. At this time, a pair of the feed rollers 9 sandwich the trailing edge of the recording material P.
  • the feed rollers 9 slip on each side of the recording material P.
  • the electrophotographic printing machine comes into a stand-by state, and the main motor 23 is suspended if a printing start signal is not generated within a predetermined time.
  • the stand-by state if the printing start signal is generated, all of the rotating sections except the register rollers 12 are rotated by the rotation transmission mechanism.
  • the toner 5 stored in the developer vessel 8 is held on the surface of the developer sleeve 3a by an alternating magnetic field generated by the clockwise rotation of the magnetic roller 4, and then transported in a counterclockwise direction, i.e., in a direction opposite to the rotating direction of the photoreceptor drum 1, over the surface of the developer sleeve 3a.
  • the stack 5a of the toner 5 is formed in the vicinity of the photoreceptor drum 1 and the developer sleeve 3a (see Fig. 1).
  • the toner 5 in contact with the photoreceptor drum 1 does not adhere to the photoreceptor drum 1 because, when the surface of the photoreceptor drum 1 has the same electric potential as the developer sleeve 3a, the Coulomb force exerted between the toner 5 and the surface of the photoreceptor drum 1 becomes extremely weak and balances the magnetic force generated by the magnetic roller 4.
  • an exposing operation is carried out by the exposure unit 2. More specifically, as shown in Fig. 4, in the exposure unit 2, the LED corresponding to the image pattern is selected in order, and light is projected onto the area C just before a position where the photoreceptor drum 1 is separated from the toner 5 by the exposure unit 2. As a result, the resistance of the exposed portion of the photoconductive layer 101 is lowered and the surface potential of the photoconductive layer 101 at that portion and that of the electrically conductive layer 102 become substantially equal. This produces a difference in electric potential between the area C of the photoconductive layer 101 and the developer sleeve 3a. Due to the difference, the injection of electric charges from the developer sleeve 3a to the photoreceptor drum 1 through the toner 5 is performed.
  • the photoreceptor drum 1 is rotating in the direction of A, when electric charges are injected into the photoconductive layer 101 by the toner 5, the exposed portion of the photoreceptor drum 1 is moved away from the position where the photoreceptor drum 1 comes into contact with the toner 5 as illustrated in Fig. 5.
  • the toner 5 in contact with the exposed portion of the surface of the photoreceptor drum 1 keeps adhering to the surface of the photoreceptor drum 1 because an adhesive force, that is, the resultant force of the Coulomb force generated by an electric field between the developer sleeve 3a and the surface of the photoreceptor drum 1 and the van der Waals forces between the surface of the photoreceptor drum 1 and toner 5 becomes stronger than the magnetic force of the magnetic roller 4.
  • an adhesive force that is, the resultant force of the Coulomb force generated by an electric field between the developer sleeve 3a and the surface of the photoreceptor drum 1 and the van der Waals forces between the surface of the photoreceptor drum 1 and toner 5 becomes stronger than
  • the toner image formed on the surface of the photoreceptor drum 1 is transported to a position where the transfer roller 14 is located by the rotation of the photoreceptor drum 1 in the direction of arrow A as shown in Fig. 1. Then, a voltage with a polarity opposite to that of the electric charges of the toner image is applied to the transfer roller 14. As a result, the toner image on the surface of the photoreceptor drum 1 is transferred to the surface of the transfer belt 22 moving at substantially the same speed as the peripheral speed of the photoreceptor drum 1. Then, the toner image is transported by the movement of the transfer belt 22 in the D direction to a position where the heater 15 and the pressure roller 17 are located.
  • the CPU Central Processing Unit of the controller (not shown) sends out a signal to the feed solenoid 11 so that the toner image on the surface of the transfer belt 22 corresponds to the recording material P at the pressurized portion between the transfer belt 22 and the pressure roller 17 above the heater 15. Then, the register rollers 12 are released from the stop state. With the rotation of the register rollers 12, the recording material P is fed onto the transfer belt 22 through the transport path formed by the transport guides 13.
  • the recording material P is now transported to the pressurized portion between the transfer belt 22 and the pressure roller 17 by the transfer belt 22 moving toward the heater 15. Then, the recording material P overlaid on the toner image formed on the transfer belt 22 is fed to pass between the heater 15 and the pressure roller 17. As a result, the toner image is transferred to and fixed on the recording material P at the same time. Namely, when the recording material P is fed while being pressurized between the transfer belt 22 and the pressure roller 17, the toner 5 on the surface of the transfer belt 22 is fused by the heat of the heater 15. Since the fused toner 5 is separated from the surface of the transfer belt 22 more easily than from the surface of the recording material P, almost all of the toner 5 on the transfer belt 22 is transferred to and fixed on the recording material P.
  • the recording material P carrying thereon the fixed toner image lifts the discharge actuator 18 and is discharged from the machine through the recording material discharge opening by the rotation of the transport rollers 20.
  • the conducting of electricity to the resistance heater 16 of the heater 15 and the driving of the main motor 23 are stopped, indicating the end of a cycle of the sequential process.
  • the recording material P is transported while being guided by the transport guide plates 13 to the moving transfer belt 22 attached around the transfer roller 14, the tension roller 21 and the heater 15.
  • the recording material P transported to the transfer belt 22 is stably transported to the transfer and fixing section as a stable transport force is evenly applied to the recording material P.
  • the image is formed without using the charger 52 such as a corona discharger installed over the photoreceptor drum 31 in a conventional machine employing the Carlson process shown in Fig. 8. It is therefore possible to make the size of the machine smaller totally. Additionally, since the corona discharger is not used, a high voltage electric supply is not required, preventing ozone.
  • the transfer unit 55 including a corona discharger used in the conventional machine.
  • This arrangement allows a reduction in the size of the machine overall and the transfer and fixing operations to be performed simultaneously. Consequently, in comparison to a conventional process in which after transferring the image to the recording material such as paper, the recording material is transported to the fusing unit for fixing the image thereon, distortion of the toner image is restrained, and thereby forming a clear image.
  • the exposure unit 2 is located inside the photoreceptor drum 1, different from a conventional machine, no extra space is required for the installation of the exposure unit. This arrangement makes it possible to further reduce the size of the machine overall. Besides, since the exposure unit 2 is covered with the photoreceptor drum 1, the light emitting section of the exposure unit 2 is prevented from getting dirty. As a result, the amount of light irradiated by the exposure unit 2 is maintained stably over a long period of time, thereby maintaining the image of good quality.
  • an electrophotographic printing machine of this embodiment includes: photoreceptor means having a photoconductive layer; toner-image forming means for forming a toner image on a surface of the photoreceptor means; moving means which moves while making contact with the surface of the photoreceptor means, the moving means having at least a dielectric surface in contact with the photoreceptor means; transfer means for transferring the toner image formed on the surface of the photoreceptor means to the moving means; transfer and fusing means, mounted in contact with the moving means, for transferring the toner image on the moving means to recording material and fixing it thereon; and recording material transport means for transporting the recording material onto the moving means moving toward the transfer and fusing means.
  • the moving means stably applies a continuous transport force to the recording material evenly until the recording material reaches the transfer and fusing means. Namely, the recording material is stably transported to the transfer and fusing means.
  • this electrophotographic printing machine is capable of fixing the toner image on the recording material without distortion.
  • An electrophotographic printing machine of this embodiment is identical to that of the first embodiment, except for the additional incorporation of a support plate 26 (support member) installed underneath the transfer belt 22 at a position where the recording material P to be transported onto the transfer belt 22 comes into contact with the transfer belt 22.
  • the support plate 26 is placed along the cross direction of the transfer belt 22 and is attached thereto so as to keep the transfer belt 22 flat. When the transfer belt 22 moves, it slides over the support plate 26.
  • the support plate 26 can be an insulating or electrically conductive plate and its material is not restricted if it has a predetermined rigidity and if its surface which comes slidingly contact with the transfer belt 22 is flat.
  • the surface of the transfer belt 22 with which the recording material P transported through the transport guide plates 13 comes into contact is kept flat by the support plate 26, thereby reducing the change in the area of the contact region of the recording material P and the transfer belt 22.
  • the support plate 26 does not exist, when the leading edge of the recording material P comes into contact with the transfer belt 22, the transfer belt 22 undulates. This causes a change in the area of the contact region of the recording material P and the transfer belt 22.
  • such a change in the area of the contact region is avoided by the installation of the support plate 26.
  • the transfer belt 22 slides over the support plate 26 the transfer belt 22 is charged and the adhesiveness between the transfer belt 22 and recording material P is intensified because static electricity is generated between the transfer belt 22 and the recording material P.
  • the configuration of this embodiment together with the effects of the present invention described in the first embodiment prevents the displacement of the image due to the deterioration of adhesiveness of the transfer belt 22 and the recording material P, and restrains the distortion and displacement of the image fixed on the recording material P by the heater 15, achieving stable image formation.
  • the transport guide plates 13 are made of conductive material such as metal, respectively, and if the support plate 26 is connected to a power supply 30 for applying a predetermined direct voltage, the formation of image is performed in a further stabilized manner.
  • an electrophotographic printing machine of this embodiment includes: photoreceptor means having a photoconductive layer; toner-image forming means for forming a toner image on a surface of the photoreceptor means; moving means which moves while making contact with the surface of the photoreceptor means, the moving means having at least a dielectric surface in contact with the photoreceptor means; transfer means for transferring the toner image formed on the surface of the photoreceptor means to the moving means; transfer and fusing means, mounted in contact with the moving means, for transferring the toner image on the moving means to recording material and fixing it thereon; recording material transport means for transporting the recording material onto the moving means moving toward the transfer and fusing means; and a support member for supporting the moving means to be flat, the support member being disposed underneath the moving means at a contacting position of the moving means and the recording material so that the moving means slides over the support member.
  • the moving means stably applies a continuous transport force evenly to the recording material until the recording material reaches the transfer and fusing means.
  • the support member reduces the change in the area of the contact region of the recording material and the moving means.
  • the moving means since the moving means is charged when the moving means slides along the support member, the adhesiveness between the recording material and the moving means is intensified.
  • the moving means applies the transport force to the recording material in a highly stable manner, and the recording material is accurately transported to the transfer and fusing means.
  • the electrophotographic printing machine is capable of fixing the toner image on the recording material without distortion.
EP19930100821 1992-01-21 1993-01-20 Elektrophotographisches Druckgerät Expired - Lifetime EP0552745B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP8489/92 1992-01-21
JP848992A JPH05197241A (ja) 1992-01-21 1992-01-21 電子写真装置

Publications (3)

Publication Number Publication Date
EP0552745A2 true EP0552745A2 (de) 1993-07-28
EP0552745A3 EP0552745A3 (en) 1993-10-27
EP0552745B1 EP0552745B1 (de) 1997-05-14

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EP19930100821 Expired - Lifetime EP0552745B1 (de) 1992-01-21 1993-01-20 Elektrophotographisches Druckgerät

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Country Link
EP (1) EP0552745B1 (de)
JP (1) JPH05197241A (de)
DE (1) DE69310556T2 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7956064B2 (en) 2006-09-01 2011-06-07 Cylene Pharmaceuticals, Inc. Fused tricyclic compounds as serine-threonine protein kinase and PARP modulators

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JPS56149076A (en) * 1980-04-21 1981-11-18 Konishiroku Photo Ind Co Ltd Copying apparatus
US4439462A (en) * 1981-04-03 1984-03-27 Konishiroku Photo Industry Co., Ltd. Method for transferring and fixing a toner image
JPS63223678A (ja) * 1987-03-13 1988-09-19 Canon Inc 画像形成装置
EP0364855A1 (de) * 1988-10-13 1990-04-25 Océ-Nederland B.V. Verfahren und Gerät zum Übertragen eines Pulverbildes, bestehend aus elektrostatisch geladenem Entwicklerpulver von einem Bildaufzeichnungsträger zu einem Bildempfangsträger
EP0482654A2 (de) * 1990-10-24 1992-04-29 Seiko Epson Corporation Bilderzeugungsgerät
DE4204470A1 (de) * 1991-02-15 1992-08-20 Toshiba Kawasaki Kk Elektrostatographisches geraet
EP0510680A2 (de) * 1991-04-26 1992-10-28 Nec Corporation Elektrofotografisches Druckgerät mit einem endlosen Band für primäre und sekundäre Übertragung
DE4213236A1 (de) * 1991-04-22 1992-11-05 Hitachi Ltd Elektrofotografisches kopiergeraet mit einem bandartigen tonerbildtraeger
EP0523631A2 (de) * 1991-07-15 1993-01-20 Sharp Kabushiki Kaisha Elektrophotographisches Druckgerät
EP0533176A2 (de) * 1991-09-20 1993-03-24 Sharp Kabushiki Kaisha Elektrophotographisches Druckgerät

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56149076A (en) * 1980-04-21 1981-11-18 Konishiroku Photo Ind Co Ltd Copying apparatus
US4439462A (en) * 1981-04-03 1984-03-27 Konishiroku Photo Industry Co., Ltd. Method for transferring and fixing a toner image
JPS63223678A (ja) * 1987-03-13 1988-09-19 Canon Inc 画像形成装置
EP0364855A1 (de) * 1988-10-13 1990-04-25 Océ-Nederland B.V. Verfahren und Gerät zum Übertragen eines Pulverbildes, bestehend aus elektrostatisch geladenem Entwicklerpulver von einem Bildaufzeichnungsträger zu einem Bildempfangsträger
EP0482654A2 (de) * 1990-10-24 1992-04-29 Seiko Epson Corporation Bilderzeugungsgerät
DE4204470A1 (de) * 1991-02-15 1992-08-20 Toshiba Kawasaki Kk Elektrostatographisches geraet
DE4213236A1 (de) * 1991-04-22 1992-11-05 Hitachi Ltd Elektrofotografisches kopiergeraet mit einem bandartigen tonerbildtraeger
EP0510680A2 (de) * 1991-04-26 1992-10-28 Nec Corporation Elektrofotografisches Druckgerät mit einem endlosen Band für primäre und sekundäre Übertragung
EP0523631A2 (de) * 1991-07-15 1993-01-20 Sharp Kabushiki Kaisha Elektrophotographisches Druckgerät
EP0533176A2 (de) * 1991-09-20 1993-03-24 Sharp Kabushiki Kaisha Elektrophotographisches Druckgerät

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Title
JOURNAL OF APPLIED PHYSICS vol. 63, no. 11, 1 June 1988, NEW YORK US pages 5589 - 5593 TETSUTANI ET AL. 'PHOTORECEPTOR CHARGING MECHANISM BY CONDUCTIVE PARTICLE RUBBING AND APPLICATION TO A NOVEL ELECTROGRAPHIC PRINTING TECHNOLOGY' *
PATENT ABSTRACTS OF JAPAN vol. 13, no. 19 (P-814)18 January 1989 & JP-A-63 223 678 ( CANON K.K. ) 19 September 1988 *
PATENT ABSTRACTS OF JAPAN vol. 6, no. 30 (P-103)(908) 23 February 1982 & JP-A-56 149 076 ( KONISHIROKU SHASHIN KOGYO K.K. ) 18 November 1981 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7956064B2 (en) 2006-09-01 2011-06-07 Cylene Pharmaceuticals, Inc. Fused tricyclic compounds as serine-threonine protein kinase and PARP modulators
US9062043B2 (en) 2006-09-01 2015-06-23 Senhwa Biosciences, Inc. Fused tricyclic compounds as serine-threonine protein kinase and PARP modulators

Also Published As

Publication number Publication date
DE69310556T2 (de) 1997-12-18
JPH05197241A (ja) 1993-08-06
EP0552745B1 (de) 1997-05-14
EP0552745A3 (en) 1993-10-27
DE69310556D1 (de) 1997-06-19

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