JP2006259524A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of effectively suppressing or preventing image quality decline in the case of transferring toner images to a transfer medium even while improving the using efficiency of toner. <P>SOLUTION: The toner raked off with a cleaning blade 52 when a toner band is formed on the outer peripheral surface of a photoreceptor drum 12 is returned through a first carrying path 72, a second carrying path 86 and a third carrying path 96 to a developing unit 28. To the contrary, when the cleaning blade 52 rakes off residual toner from the outer peripheral surface of the photoreceptor drum 12, a motor actuator 108 is operated, a support piece 108 is lowered, and the second carrying path 86 is turned by gravity. Thus, when the other end of the second carrying path 86 separates from the third carrying path 96, the toner falls without being able to go across the third carrying path 86 and is gathered in a recovery box 112. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus for forming a toner image on a transfer medium such as paper such as a copying machine, a facsimile machine, and a printer.

  Image forming apparatuses such as copying machines, laser printers, and facsimile machines include image forming apparatuses to which a so-called electrophotographic system is applied. This type of image forming apparatus includes a photosensitive drum as an image carrier.

  The photosensitive drum rotates around its own axis when a driving force is applied. On the side of the outer peripheral surface of the photosensitive drum, a charger, an exposure unit, and a developing unit are provided in order along the rotational circumferential direction of the photosensitive drum.

  The rotating photosensitive drum is charged uniformly by being charged on the outer peripheral surface (surface) by facing the charger along the rotational radius direction. Next, a portion of the outer peripheral surface of the photosensitive drum facing the exposure unit is irradiated with a light beam based on image data, thereby forming an electrostatic latent image on the outer peripheral surface of the photosensitive drum. The

  Further, fine powdery toner adheres to the portion of the outer peripheral surface of the photosensitive drum facing the developing unit and the portion where the electrostatic latent image is formed, whereby the toner is deposited on the outer peripheral surface of the photosensitive drum. An image is formed. The toner image thus formed is transferred to a transfer medium such as paper, whereby an image is formed on the transfer medium.

  On the other hand, in such an image forming apparatus, it is necessary to remove the so-called “residual toner” remaining on the outer peripheral surface of the photosensitive drum after the transfer of the toner image onto the transfer medium.

  To remove such residual toner, a blade formed of an elastic body is pressed against the outer peripheral surface of the rotating photosensitive drum, and the residual toner attached to the outer peripheral surface of the photosensitive drum is scraped off. Has been done. Further, in the configurations disclosed in Patent Document 1 and Patent Document 2 below, a rotating brush is provided upstream of the blade in the rotational direction of the photosensitive drum.

  The rotating brush has a rotating shaft parallel to the rotating shaft center of the photosensitive drum, and bristles are formed on the outer periphery of the rotating shaft. The rotating brush brings the bristles into contact with the outer peripheral surface of the photosensitive drum while rotating the rotating shaft. As described above, when the bristles come into contact with the outer peripheral surface of the photosensitive drum, the bristles come into contact with the residual toner adhering to the outer peripheral surface of the photosensitive drum, whereby the residual toner is scraped off, or The adhesion of the residual toner to the outer peripheral surface of the photosensitive drum is weakened, and the residual toner is easily scraped off by the blade.

  On the other hand, since the blade as described above is always in contact with the outer peripheral portion of the photosensitive drum, a small particle size toner is caught between the blade tip and the photosensitive drum, The blade may be melted and fixed to the blade by friction with the rotating photosensitive drum.

  If the photosensitive drum is rotated in a state where toner is fixed to the blade between the tip of the blade and the photosensitive drum, the outer peripheral surface of the photosensitive drum is damaged or the blade is deteriorated.

As one means for preventing such a problem, a toner band is formed on the outer peripheral surface of the photosensitive drum, and the toner band is removed by the blade, so that the tip of the blade and the photosensitive drum are removed as described above. It is conceivable to remove the toner adhering to the blade between them (refer to Patent Documents 3 and 4 below for the toner band).
JP-A-4-232985 JP-A-9-138623 JP-A-7-306625 JP-A-8-335008

  On the other hand, from the viewpoint of toner use efficiency and environmental viewpoint, the toner scraped off from the photosensitive drum by a blade or the like is returned to the developing device and reused.

  Here, the toner constituting the toner band described above is suitable for reuse because it has few charging defects and is of relatively high quality. On the other hand, the residual toner is toner that was supposed to be transferred to a transfer medium such as paper, but was not transferred due to poor charging or the like. For this reason, there is a problem that by reusing such residual toner, the image quality when the toner image is transferred to the paper is lowered.

  In view of the above-described facts, an object of the present invention is to obtain an image forming apparatus that can effectively suppress or prevent deterioration in image quality when a toner image is transferred to a transfer medium while improving toner use efficiency. .

  In the image forming apparatus according to the first aspect of the present invention, the developing unit applies toner to the image carrier on which the electrostatic latent image is formed on the outer peripheral surface while rotating or moving within a predetermined range. The image forming apparatus for forming a toner image corresponding to the electrostatic latent image on the outer peripheral surface of the image carrier and transferring the toner image onto a transfer medium, wherein the image carrier is rotated more than the developing unit. The electrostatic latent image is formed on the outer peripheral surface of the image carrier based on image information to be transferred to the transfer medium, and is provided on the upstream side in the direction or the moving direction, and the image carrier at a predetermined timing. An electrostatic latent image forming means for forming an electrostatic latent image for forming a toner band on the outer peripheral surface of the body; and the image carrier than the transfer position for transferring the toner image to the transfer medium with respect to the transfer medium. Downstream direction of body rotation or movement A removing means provided to contact the outer peripheral surface of the image carrier and scrape off the toner adhering to the outer peripheral surface of the image carrier; and to collect the toner scraped off by the removing means; And a collecting unit that supplies only the toner scraped off by the removing unit to the developing unit at a predetermined timing when the toner band is formed.

  According to the image forming apparatus of the first aspect of the present invention, the electrostatic latent image is formed on the outer peripheral surface of the image carrier that rotates or moves within a predetermined range based on the image information to be transferred to the transfer medium. An electrostatic latent image is formed by the forming means. When the developing means applies toner to the outer peripheral surface of the image carrier on which the electrostatic latent image is formed in this manner, a toner image corresponding to the electrostatic latent image is formed on the outer peripheral surface of the image carrier. The toner image is transferred to a transfer medium, whereby an image is formed on the transfer medium.

  Further, on the downstream side of the transfer direction of the toner image relative to the transfer medium with respect to the rotation direction or movement direction of the image carrier, the removing means is in contact with the outer peripheral surface of the image carrier, and The toner adhering to the outer peripheral surface of the carrier (hereinafter, the toner adhering to the outer peripheral surface of the image carrier after transfer of the toner image is referred to as “residual toner” for convenience) is removed by the removing means. It is scraped off from the outer peripheral surface. As a result, the outer peripheral surface of the image carrier is cleaned and again used for forming a toner image.

  On the other hand, in the image forming apparatus according to the present invention, a predetermined timing, for example, immediately after starting the image forming apparatus or immediately before stopping, or before or after the toner image is formed in the operation state of the image forming apparatus. In addition, an electrostatic latent image for forming a toner band on the outer peripheral surface of the image carrier is formed on the outer peripheral surface of the image carrier by the electrostatic latent image forming means.

  In this state, when toner is applied to the outer peripheral surface of the image carrier by the developing means, a toner band is formed on the outer peripheral surface of the image carrier. Since the transfer medium does not exist at the transfer position when the toner band passes through the transfer position, the toner constituting the toner band passes through the transfer position while adhering to the outer peripheral surface of the image carrier.

  Further, the toner constituting the toner band that has passed through the transfer position is scraped off from the outer peripheral surface of the image carrier by the removing means. As described above, in the image forming apparatus according to the present invention, the toner constituting the toner band formed on the outer peripheral surface of the image carrier at a predetermined timing is not transferred to the transfer medium unlike the residual toner. Therefore, foreign matters such as paper dust are not easily mixed with the toner, and the amount of toner is large because it is not transferred to the transfer medium.

  Therefore, the toner constituting the toner band is scraped off by the removing unit, for example, the toner adhering to the removing unit between the outer peripheral surface of the image carrier and the removing unit is removed from the removing unit. It is possible to improve the toner removal performance by the removing means.

  Here, in the image forming apparatus according to the present invention, of the toner removed by the removing unit, the toner scraped off by the removing unit at a predetermined timing when the toner band is formed, that is, basically the toner. Only the toner constituting the band is collected by the collecting means and supplied to the developing means. As described above, the toner collected by the collecting unit is supplied to the developing unit and used for the formation of a toner image and the formation of a toner band, thereby improving the use efficiency of the toner.

  In addition, as described above, the residual toner is often mixed with foreign matters such as paper dust or is poorly charged. However, in the image forming apparatus according to the present invention, the collecting means basically supplies only the toner constituting the toner band to the developing means. For this reason, the toner supplied to the developing means by the collecting means is of higher quality than the residual toner. As a result, the deterioration of image quality when the toner image is formed with the toner supplied to the developing unit by the collecting unit is effectively reduced.

  According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect of the present invention, wherein the image bearing member is moved between the contact position of the removing unit with respect to the image bearing member and the transfer position. Adhesive force which is provided so as to be movable toward and away from the outer peripheral surface and reduces the adhesive force of the toner by approaching the outer peripheral surface of the image carrier and contacting the toner attached to the outer peripheral surface of the image carrier. The adhesion reducing means is arranged on the outer periphery of the image carrier at a predetermined timing when the electrostatic latent image forming means forms an electrostatic latent image for forming the toner band on the image carrier. And a control means for separating from the surface.

  According to the image forming apparatus of the present invention, the adhesion force is reduced between the contact position of the removing unit with respect to the image carrier and the transfer position for transferring the toner image from the image carrier to the transfer medium. Means are provided. In a state where the adhesion force reducing means is close to the outer peripheral surface of the image carrier, the adhesion force of the toner to the outer peripheral surface of the image carrier is weakened by the adhesion force reducing means.

  Accordingly, when the adhesive force of the residual toner to the outer peripheral surface of the image carrier is weakened by the adhesive force reducing means, when the head is moved to the removing means together with the rotating or moving image carrier, the residual means ensures that the residual toner is image-bearing by the removing means. It is scraped off from the outer peripheral surface of the body.

  On the other hand, when the electrostatic latent image forming means forms an electrostatic latent image for forming a toner band on the outer peripheral surface of the image carrier, the control means starts at a predetermined timing corresponding to the formation of the electrostatic latent image. The adhesion reducing means is separated from the outer peripheral surface of the image carrier. As described above, the adhesion reducing means is not brought into contact with the toner constituting the toner band because the adhesion reducing means is separated from the outer peripheral surface of the image carrier.

  For this reason, the toner constituting the toner band is not disturbed by the adhesion reducing means, or is not carelessly scattered around, and is scraped off by the removing means. As a result, the toner constituting the toner band can be efficiently collected, and the effect of forming the toner band, that is, the toner adhering to the removing means between the outer peripheral surface of the image carrier and the removing means is removed. The toner can be removed from the means, and the toner removal performance by the removing means can be reliably improved.

  In the present invention, the adhesion reducing means may be configured to mechanically interfere with the toner adhering to the outer peripheral surface of the image carrier to weaken the adhesion, or electrostatically. A configuration in which electrostatic toner adhesion is weakened by applying a charge having a polarity different from that of the charge of the toner to the toner attached to the outer peripheral surface of the image carrier.

  As described above, in the image forming apparatus according to the present invention, it is possible to effectively suppress or prevent a deterioration in image quality when a toner image is transferred to a transfer medium while improving toner use efficiency.

<Configuration of the present embodiment>
FIG. 1 shows a schematic configuration of an image forming apparatus 10 according to an embodiment of the present invention. First, the overall configuration of the image forming apparatus 10 will be described with reference to FIG.

(Outline of configuration of image forming apparatus 10)
As shown in FIG. 1, the image forming apparatus 10 includes a photosensitive drum 12 as an image carrier. The photosensitive drum 12 is formed in a columnar shape or a cylindrical shape as a whole, and is pivotally supported by a supporting means (not shown) such as a frame so as to be rotatable at least around the central axis in the direction of arrow C in FIG. .

  Further, the photosensitive drum 12 is mechanically connected to a motor (not shown) as a driving means via a reduction gear train constituted by a plurality of gears, a driving force transmission mechanism (deceleration mechanism) constituted by a pulley, an endless belt, and the like. Are connected to each other, and the driving force of the motor is transmitted to the photosensitive drum 12, whereby the photosensitive drum 12 rotates around its own central axis.

  A charger 14 as a charging unit is provided on the side of the outer peripheral portion of the photosensitive drum 12 along the rotational radius direction of the photosensitive drum 12. The charger 14 includes a charging roll 16.

  The charging roll 16 is generally formed in a columnar shape or a cylindrical shape, and its central axis is provided in parallel to the central axis of the photosensitive drum 12. The charging roll 16 is electrically connected to a charger power supply 18. The charger power supply 18 is composed of, for example, a transformer and is electrically connected to a main power supply (not shown) of the image forming apparatus 10. A voltage is applied to 16.

  The outer peripheral surface of the charging roll 16 is continuously in contact with the outer peripheral surface of the photosensitive drum 12 along the axial direction thereof, and the charging roll 16 to which a voltage is applied contacts the photosensitive drum 12. The portion of the photosensitive drum 12 that contacts the charging roll 16 is uniformly charged along the central axis direction.

  Further, an exposure unit 20 as an electrostatic latent image forming unit (exposure unit) is provided on one side in the rotational circumferential direction of the photosensitive drum 12 with respect to the charger 14 (arrow C in FIG. 1). The exposure unit 20 includes, for example, an image input unit 22 configured to include a laser light source such as a semiconductor laser and a scanning mechanism such as a polygon mirror.

  The laser light source constituting the image input device 22 is electrically connected to an image control unit 24 as image processing means. Furthermore, the image control unit 24 is electrically connected to, for example, a scanner 26 serving as an image reading unit.

  The scanner 26 continuously reads an image along a direction corresponding to the central axis direction of the photosensitive drum 12 and outputs an electric signal corresponding to the read image information. The electric signal output from the scanner 26 is input to the image control unit 24, and the laser light source of the image input device 22 is controlled according to the input electric signal.

  Thus, the laser beam output from the laser light source of the image input device 22 controlled by the image control unit 24 is moved to a predetermined position on the outer peripheral portion of the photosensitive drum 12 along the circumferential direction of the photosensitive drum 12 by the scanning mechanism. Further, the outer peripheral surface of the photosensitive drum 12 is irradiated while moving along the central axis of the photosensitive drum 12. Thereby, an electrostatic latent image is formed on the outer peripheral surface of the photosensitive drum 12.

  Further, a developing device 28 as a developing unit is provided on one side in the rotational circumferential direction of the photosensitive drum 12 with respect to the exposure device 20 (in the direction of arrow C in FIG. 1). A toner cartridge (not shown) is detachably provided in the developing device 28. The toner cartridge contains fine powder toner.

  When the toner cartridge is mounted on the developing unit 28, the developing roller (not shown) provided on the developing unit 28 or the toner cartridge is rotated so that the toner can adhere to the outer peripheral surface of the photosensitive drum 12. Then, the toner electrostatically adheres to the outer peripheral surface of the photosensitive drum 12, whereby a toner image corresponding to the electrostatic latent image is formed on the outer peripheral surface of the photosensitive drum 12.

  Further, a transfer device 30 as a transfer unit is provided on one side in the rotation circumferential direction of the photosensitive drum 12 (in the direction of arrow C in FIG. 1) with respect to the developing device 28. The transfer device 30 includes a transfer roller 32. The transfer roller 32 is formed in a columnar shape or a cylindrical shape whose central axis is parallel to the photosensitive drum 12, and the outer peripheral surface is circumscribed on the outer peripheral surface of the photosensitive drum 12.

  The transfer roller 32 has conductivity, and an electric field is formed between the transfer roller 32 and a sheet 34 as a transfer medium fed between the photoconductor drum 12 and the outer surface of the photoconductor drum 12. While transferring the toner constituting the formed toner image to the paper 34, the paper 34 is pressed to fix the transferred toner to the paper 34.

  Further, a cleaning device 50 as a cleaning unit is provided on one side (in the direction of arrow C in FIG. 1) of the photosensitive drum 12 with respect to the transfer device 30, and further, with respect to the cleaning device 50. A static eliminator 36 is provided on one side (in the direction of arrow C in FIG. 1) of the photosensitive drum 12 in the rotational circumferential direction.

  The static eliminator 36 includes a light source 38 composed of a tungsten lamp, an LED, or the like, and light emitted from the light source 38 is irradiated on the outer peripheral surface of the photosensitive drum 12, so that the light is irradiated at a portion irradiated with light. The electric potential on the outer peripheral surface of the photosensitive drum 12 becomes “0”, whereby the electric charge on the outer peripheral surface of the photosensitive drum 12 is removed.

(Configuration of the cleaning device 50)
As shown in FIGS. 1 and 2, the cleaning device 50 includes a cleaning blade 52 as a removing means. The cleaning blade 52 is formed in a plate shape having a longitudinal direction in the direction along the central axis of the photosensitive drum 12 by a urethane-based synthetic resin material having a type A durometer hardness of about 75 degrees.

  A tapered portion 54 is formed on one side of the cleaning blade 52 in the width direction intermediate portion. The tapered portion 54 is formed in a tapered shape (wedge shape) whose thickness dimension gradually decreases toward one end in the width direction of the cleaning blade 52, and the end portion of the tapered portion 54, that is, one end portion in the thickness direction of the cleaning blade 52. Are in sliding contact with the outer peripheral portion of the photosensitive drum 12 uniformly at a contact pressure of about 4.0 gf / mm.

  As shown in FIGS. 2 and 3, the other side in the rotational circumferential direction of the photosensitive drum 12 with respect to the cleaning blade 52 (the direction opposite to the arrow C in FIGS. 1 and 2) is an adhesion reducing means. A brush 56 is provided. The brush 56 includes a core member 58 whose central axis is parallel to the central axis of the photosensitive drum 12. Arms 60 are provided on both axial ends of the core member 58.

  The core member 58 is rotatably supported at the tips of both arms 60 and is mechanically connected to a motor actuator (not shown). This motor actuator includes a motor as a brush drive means and a speed reduction means (or drive force transmission means) composed of a plurality of gears for reducing the rotational force of the motor, and the motor drive force is reduced by the speed reduction means. It is transmitted to the core material 58 via. The core member 58 to which the driving force is transmitted rotates around the axis of the core member 58 in the direction opposite to the rotation direction of the photosensitive drum 12.

  On the other hand, as shown in FIGS. 1 and 2, a motor actuator 62 as arm driving means constituting control means according to claim 2 is provided at the base end portion of the arm 60. ing.

  The motor actuator 62 includes a motor as drive means and a speed reduction means (or drive force transmission means) composed of a plurality of gears for reducing the rotational force of the motor. The motor drive force is transmitted via the speed reduction means. Transmitted to the arm 60. The arm 60 to which the driving force is transmitted rotates the tip about the base end portion, so that the tip of the arm 60 contacts and separates from the outer peripheral surface of the photosensitive drum 12.

  Further, as shown in FIG. 4, the motor actuator 62 is connected to a power source 66 via a driver 64 and is electrically connected to a cleaning controller 68, and the cleaning control input to the driver 64. Based on the control signal from the device 68, the motor actuator 62 operates.

  As shown in FIGS. 2 and 3, the core material 58 is provided with innumerable bristles 70. In this embodiment, the bristles 70 are flocked to the outer periphery of the core material 58 at a density of 360 nylon fibers having a thickness of about 10 denier per square inch.

  These bristles 70 are set to have lengths so that the tips can come into contact with the outer peripheral surface of the photosensitive drum 12 with the tips of the arms 60 approaching the outer peripheral surface of the photosensitive drum 12. Then, it comes into contact with the toner adhering to the outer peripheral surface of the photosensitive drum 12, that is, residual toner described later.

  On the other hand, as shown in FIGS. 1 to 3, a first conveyance path 72 that constitutes a collection unit as a first conveyance unit is provided between the cleaning blade 52 and the brush 56. The first transport path 72 is formed in a rectangular box shape which is formed in a longitudinal direction along the central axis of the photosensitive drum 12, and an upper end thereof is open. The longitudinal dimension of the first transport path 72 is equal to or greater than the axial dimension of the photosensitive drum 12 and the longitudinal dimension of the cleaning blade 52.

  Both ends of the first transport path 72 are positioned outside both ends of the photosensitive drum 12 in the axial direction, and the toner scraped off by the cleaning blade 52 is accommodated in the first transport path 72.

  In addition, a screw conveyor 74 that constitutes a collecting means as a first conveying means is provided inside the first conveying path 72 together with the first conveying path 72. The screw conveyor 74 includes a shaft 78 that is rotatably supported at both ends by side walls 76 on both sides in the longitudinal direction of the first conveyance path 72. One end of the shaft 78 is connected to a motor actuator 80 that constitutes a collecting means as a driving means for the first conveying means provided outside the one side wall 76.

  Similarly to the motor actuator 62, the motor actuator 80 includes a motor as drive means and speed reduction means (or drive force transmission means) composed of a plurality of gears for reducing the rotational force of the motor. The driving force is transmitted to the shaft 78 through the speed reduction means. The shaft 78 to which the driving force is transmitted rotates around its own axis.

  A spiral blade 82 is formed on the outer periphery of the shaft 78. When the spiral blade 82 rotates together with the shaft 78 by receiving a driving force from the motor actuator 80, the toner that has fallen into the first conveyance path 72 spirals. It is transported to the other end in the longitudinal direction of the first transport path 72 by the wings 82.

  On the other hand, in the vicinity of the other end portion in the longitudinal direction of the first transport path 72, the bottom wall 84 of the first transport path 72 is open, and the toner transported to the vicinity of the other end portion in the longitudinal direction of the first transport path 72 is the first. It falls from one conveyance path 72.

  Further, a second transport path 86 constituting a collection means is provided as a second transport means on the lower side in the vicinity of the other end in the longitudinal direction of the first transport path 72. The second transport path 86 is provided on the side of one end of the photosensitive drum 12 in the axial direction, and is formed in a box shape whose longitudinal direction intersects the first transport path 72 and whose upper end is opened. The toner dropped from the opening of the bottom wall 84 at the other end in the longitudinal direction of the first transport path 72 is accommodated at one end in the longitudinal direction of the second transport path 86.

  Inside the second conveyance path 86, a screw conveyor 88 that constitutes a collection means as a second conveyance means together with the second conveyance path 86 is provided. The screw conveyor 88 has substantially the same configuration as the screw conveyor 74, and the shaft 78 of the screw conveyor 88 is connected to a motor actuator 92 provided outside the side wall 90 on one end side in the longitudinal direction of the second conveyance path 86. 78, the driving force from the motor actuator 92 is received by the shaft 78 of the screw conveyor 74, and the spiral blade 82 of the screw conveyor 74 is rotated, so that the second conveying path 86 is conveyed to the other end in the longitudinal direction. .

  In the vicinity of the other end portion in the longitudinal direction of the second transport path 86, the side wall 94 on one side in the width direction of the second transport path 86 (photosensitive drum 12 side) is open. Further, as shown in FIG. 3, the developing device 28 is provided with a third transport path 96 that constitutes a collection unit as a third transport unit corresponding to the opening of the side wall 94.

  The third conveyance path 96 is formed in a cylindrical shape having a substantially rectangular cross section or a box shape having an open upper end, and the toner conveyed to the vicinity of the other end in the longitudinal direction of the second conveyance path 86 passes through the opening in the side wall 94. 2 moves outside the conveyance path 86, and is recovered by the sliding developer 28 on the third conveyance path 96.

  On the other hand, as shown in FIGS. 1 and 2, an attachment piece 98 is formed on one end side in the longitudinal direction of the second conveyance path 86, and the second conveyance path 86 is formed by the shaft 100 penetrating the attachment piece 98. The photosensitive drum 12 is rotatably supported around an axis parallel to the central axis of the photosensitive drum 12.

  Further, as shown in FIG. 1 to FIG. 3, a plate-like support piece 102 having a thickness direction along the vertical direction is provided on the other longitudinal end side of the second transport path 86. The second transport path 86 is placed on the support piece 102 at the other end side in the direction, and the other end side in the longitudinal direction of the second transport path 86 is supported by the support piece 102.

  A pair of guide rods 104 extending in the longitudinal direction passes through the support piece 102, and a ball screw 106 extending in the longitudinal direction passes through the support piece 102. A female screw corresponding to the ball screw 106 is formed in a portion where the ball screw 106 of the support piece 102 penetrates, and is screwed into the ball screw 106. As shown in FIGS. 1 and 2, the lower end of the ball screw 106 is connected to a motor actuator 108 that constitutes a collecting means.

  Similarly to the motor actuator 62, the motor actuator 108 includes a motor as drive means and speed reduction means (or drive force transmission means) composed of a plurality of gears for reducing the rotational force of the motor. The force is transmitted to the ball screw 106 through the speed reduction means. The ball screw 106 to which the driving force is transmitted rotates around its own axis, and raises and lowers the support piece 102.

  As shown in FIG. 4, the motor actuator 108 is connected to a power source 66 via a driver 110 and is electrically connected to a cleaning controller 68 as a control means, and is output from the cleaning controller 68. The motor actuator 108 is driven and controlled based on the drive signal input to the driver 110.

  Further, as shown in FIGS. 1 to 3, a collection box 112 is provided below the second conveyance path 86, and cannot pass through the opening of the side wall 94 of the second conveyance path 86 to the third conveyance path 96. The toner that has fallen into the toner is collected in the collection box 112.

<Operation and effect of the present embodiment>
In the image forming apparatus 10, the photosensitive drum 12 rotates at a predetermined speed around one central axis by the driving force of the motor. Further, when the photosensitive drum 12 is rotated as described above, the electric charge is removed at the portion of the outer peripheral portion of the photosensitive drum 12 irradiated with light from the light source 38 of the static eliminator 36 and the potential difference becomes “0”. Become.

  Next, when the photosensitive drum 12 rotates and the charging roll 16 of the charger 14 contacts the outer peripheral portion of the photosensitive drum 12, the portion of the outer peripheral portion of the photosensitive drum 12 where the charging roll 16 is in contact is exposed to light. It is uniformly charged along the central axis of the body drum 12.

  Further, the photosensitive drum 12 rotates so that the uniformly charged portion of the outer peripheral portion faces the image input device 22.

  An electrical signal based on the image information read by the scanner 26 is output from the image control unit 24 to the image input unit 22, and light based on the electrical signal is irradiated to the outer peripheral portion of the photosensitive drum 12. As a result, an electrostatic latent image is formed on the outer peripheral surface of the photosensitive drum 12.

  Next, the portion of the outer peripheral portion of the photosensitive drum 12 where the electrostatic latent image is formed is opposed to the developing device 28 by the rotation of the photosensitive drum 12, and the electrostatic latent image is formed by the developing drum of the developing device 28. The toner adheres to the exposed part. As a result, a toner image corresponding to the electrostatic latent image is formed on the outer peripheral portion of the photosensitive drum 12.

  Further, the portion of the outer peripheral portion of the photoconductive drum 12 where the toner image is formed faces the transfer roller 32 of the transfer device 30 by the rotation of the photoconductive drum 12. A sheet 34 is supplied between the transfer roller 32 and the photosensitive drum 12 at a speed corresponding to the rotation speed of the photosensitive drum 12, and the photosensitive drum is generated by an electric field formed between the transfer roller 32 and the sheet 34. The toner adhering to the outer periphery of 12 moves to the paper 34. As a result, a toner image is formed on the paper 34.

  Here, in the image forming apparatus 10, as described above, when the image signal based on the normal image information is output from the scanner 26 to the image control unit 24, the cleaning controller 68 outputs the image signal from the image control unit 24. A control signal is output to the drivers 64 and 110 based on the electrical signal. Thereby, the motor actuators 62 and 108 operate.

  When the motor actuator 62 is actuated and the motor driving force of the motor actuator 62 is transmitted to the arm 60, as shown in FIG. 2, the arm 60 rotates and rotates with the motor driving force of another motor actuator. The bristles 70 of the brush 56 approach the outer peripheral portion of the photosensitive drum 12. In this state, the toner that does not move to the paper 34 but remains attached to the outer peripheral portion of the photosensitive drum 12, so-called “residual toner”, approaches the bristles 70 of the brush 56 by the rotation of the photosensitive drum 12.

  Further, the residual toner is brought into contact with the residual toner by the rotation of the photosensitive drum 12, and the residual toner is applied to the outer peripheral surface of the photosensitive drum 12 by a mechanical impact applied to the residual toner from the friction 70. As a result, the adhesion of the residual toner to the outer peripheral surface of the photosensitive drum 12 is reduced.

  Further, when the photosensitive drum 12 rotates in this state, a portion of the outer peripheral portion of the photosensitive drum 12 to which the residual toner having reduced adhesion force to the outer peripheral surface of the photosensitive drum 12 is opposed to the cleaning blade 52. As described above, since the tip of the taper portion 54 of the cleaning blade 52 is in contact with the outer peripheral surface of the photosensitive drum 12, residual toner adhering to the outer peripheral surface of the photosensitive drum 12 interferes with the tip of the taper portion 54. As a result, the residual toner is scraped off from the outer peripheral surface of the photosensitive drum 12.

  Residual toner scraped off from the outer periphery of the photosensitive drum 12 is accommodated in the first conveyance path 72. The residual toner accommodated in the first conveyance path 72 is conveyed to the other end in the longitudinal direction of the first conveyance path 72 by the spiral blades 82 of the screw conveyor 74 that rotates by receiving the driving force of the motor of the motor actuator 80.

  Next, the residual toner transported by the spiral blades 82 of the screw conveyor 74 to the vicinity of the other end in the longitudinal direction of the first transport path 72 falls from an opening formed in the bottom wall 84 of the first transport path 72. The residual toner dropped in this way is stored in the second conveyance path 86. The residual toner accommodated in the second transport path 86 is transported to the other end in the longitudinal direction of the second transport path 86 by the spiral blades 82 of the screw conveyor 88 that rotates in response to the driving force of the motor actuator 92.

  Here, as described above, when an image signal based on normal image information is output from the scanner 26 to the image control unit 24, the cleaning controller 68 performs a driver operation based on the electrical signal output from the image control unit 24. A control signal is output to 110. Therefore, in this state, the motor actuator 108 is operated, the ball screw 106 is rotated by the driving force of the motor of the motor actuator 108, and the support piece 102 is lowered.

  When the support piece 102 is lowered, the second conveyance path 86 is rotated around the shaft 100 by its own weight, and the other end side in the longitudinal direction of the second conveyance path 86 is lowered. By lowering the other end in the longitudinal direction of the second transport path 86, the correspondence between the opening formed in the side wall 94 of the second transport path 86 and the third transport path 96 is eliminated. For this reason, in this state, the residual toner conveyed to the other end in the longitudinal direction of the second conveyance path 86 is not sent to the third conveyance path 96 but falls from the opening of the side wall 94 and is collected in the lower collection box. Collected at 112.

  On the other hand, an electric signal for forming a toner band is output from the image control unit 24 before and after the electrostatic latent image is formed on the outer peripheral portion of the photosensitive drum 12 based on the normal image information as described above. When the electric signal for forming the toner band is input, the image input device 22 irradiates light to the outer peripheral portion of the photosensitive drum 12 substantially uniformly along the central axis of the photosensitive drum 12 to thereby perform photosensitive. A substantially uniform electrostatic latent image is formed on the outer peripheral surface of the photosensitive drum 12 along the central axis of the photosensitive drum 12.

  As described above, the toner is attached to the outer peripheral surface of the photosensitive drum 12 on which the electrostatic latent image for forming the toner band is formed by the developing device 28, and thus, along the central axis of the photosensitive drum 12. A toner band having a substantially uniform thickness is formed on the outer peripheral surface of the photosensitive drum 12.

  On the other hand, the cleaning controller 68 to which such an electric signal for forming the toner band is input outputs a control signal to the drivers 64 and 110, and for example, the brush 56 is separated from the outer peripheral surface of the photosensitive drum 12. If the toner can move from the opening of the side wall 94 to the third conveyance path 96 (that is, the state shown in FIG. 1), the motor actuators 62 and 108 are kept stopped, and the brush 56 is moved to the photosensitive drum. 12, and when the toner cannot move from the opening of the side wall 94 to the third conveyance path 96 (that is, in the state shown in FIG. 2), the motor actuators 62 and 108 are operated to 60 is rotated to separate the brush 56 from the outer peripheral surface of the photosensitive drum 12, and the support piece 102 is raised to the third conveyance path 96 from the opening of the side wall 94. Trainer is a state that can be moved.

  In this state, the toner constituting the toner band does not touch the bristles 70 of the brush 56, and the toner is not disturbed by the bristles 70 of the brush 56. Therefore, the toner band basically maintains its thickness and collides with the tapered portion 54 of the cleaning blade 52.

  As a result, the toner constituting the toner band is scraped off from the outer peripheral surface of the photosensitive drum 12, and the tapered portion 54 is caused by an impact when the cleaning blade 52 collides with the toner constituting the toner band having a relatively thickness. Residual toner or the like solidified between the leading edge of the toner and the outer peripheral surface of the photosensitive drum 12 is peeled off. Accordingly, it is possible to prevent such residual toner from being damaged on the outer peripheral surface of the photosensitive drum 12 and to suppress the deterioration of the cleaning blade 52.

  Further, the toner constituting the toner band scraped off by the cleaning blade 52 as described above is transported to the vicinity of the other end in the longitudinal direction of the second transport path 86 by the screw conveyors 74 and 88.

  Here, in this state, since the toner can pass from the opening formed in the side wall 94 to the third transport path 96 as described above, the toner is collected by the developing device 28 through the third transport path 96, and again, It is used for the formation of toner images and toner bands.

  Here, in the image forming apparatus 10, as described above, when the cleaning blade 52 scrapes off the residual toner from the outer peripheral surface of the photosensitive drum 12, the residual toner is recovered in the recovery box 112, so In addition, residual toner is not collected in the developing device 28.

  For this reason, residual toner, which often has defects such as poor charging, is not used for the formation of a toner image. Therefore, even if the toner collected in the developing device 28 is used, a good quality toner image can be obtained. As a result, the quality of the image transferred onto the paper 34 can be improved.

  Further, in this embodiment, when the cleaning blade 52 scrapes off the toner constituting the toner band, the brush 56 is separated from the outer peripheral surface of the photosensitive drum 12, so that the toner is absorbed by the bristles 70 of the brush 56. Will not be disturbed. For this reason, it is possible to prevent the toner constituting a toner band having a higher quality than the residual toner from being scattered by the brush 56 without being accommodated in the first conveyance path 72. As a result, in the present embodiment, the toner constituting the toner band can be recovered to the developing device 28 very efficiently.

  In the present embodiment, the bristles 70 of the brush 56 are configured to reduce the adhesive force of the residual toner to the outer peripheral portion of the photosensitive drum 12 by mechanically contacting the residual toner. However, a configuration in which the adhesion force of residual toner to the outer peripheral portion of the photosensitive drum 12 is electrically reduced may be employed.

  That is, when the bristles 70 are brought into contact with the residual toner in a state where a voltage of about +200 V is applied to the bristles 70 of the brush 56 using, for example, a nylon CB dispersed fiber, the residual toner with respect to the outer peripheral portion of the photosensitive drum 12 Can be effectively reduced. As described above, the electrostatic adhesion force of the residual toner to the outer peripheral portion of the photosensitive drum 12 may be electrically reduced.

  In this embodiment, the collection destination of the toner conveyed in the second conveyance path 86 is changed by moving the second conveyance path 86 up and down. However, the configuration for changing the toner collection destination is not limited to such a configuration, and other examples are shown in FIGS. 5 and 6.

  In the modification shown in FIG. 5, the second conveyance path 86 is fixed, and the support piece 102, the motor actuator 108, and the ball screw 106 are not provided. Further, in this modification, an opening 134 is formed in the bottom wall 132 at the longitudinal intermediate portion of the second conveyance path 86. A cylindrical fourth transport path 136 having a lower end connected to the collection box 112 is provided below the second transport path 86 corresponding to the opening 134.

  The upper end of the fourth transport path 136 is connected to the opening 134. When the toner transported by the screw conveyor 88 falls at the opening 134, the toner slides down the fourth transport path 136 and is sent to the collection box 112. It is configured to be.

  The opening 134 is provided with a plate-like shutter 138. The shutter 138 blocks communication between the opening 134 and the fourth conveyance path 136. Furthermore, a solenoid 140 is provided outside the fourth transport path 136.

  The tip of the plunger 142 of the solenoid 140 constituting the collecting means instead of the motor actuator 108 is connected to the shutter 138. When the solenoid 140 is operated and the plunger 142 is pulled into the solenoid 140, the shutter 138 slides. Thus, the opening 134 and the fourth transport path 136 communicate with each other.

  That is, in this modification, when the residual toner is conveyed by the second conveyance path 86, the opening 134 and the fourth conveyance path 136 are communicated with each other as shown in FIG. The residual toner is sent to the collection box 112 via 136.

  On the other hand, when the toner constituting the toner band is conveyed by the second conveyance path 86, the communication between the opening 134 and the fourth conveyance path 136 is blocked by the shutter 138 as shown in FIG. The toner is returned to the developing device 28 through the second conveyance path 86.

  As described above, even in this modified example, basically the same operation as described above can be performed, and the same effect can be obtained.

1 is a front view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a front view corresponding to FIG. 1 showing a state when collecting residual toner. 1 is a plan view illustrating an outline of a configuration of an image forming apparatus according to an embodiment of the present invention. It is a block diagram of the outline of drive control of the motor actuator which moves each of a brush (adhesion force reduction means) and each support piece. It is a front view which shows the outline of a structure of the principal part of the modification of the image forming apparatus which concerns on one embodiment of this invention. FIG. 6 is a front view corresponding to FIG. 5 showing a state when collecting residual toner.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Photosensitive drum (Image carrier)
20 Exposure unit (electrostatic latent image forming means)
28 Developer (Developer)
34 Paper (transfer media)
52 Cleaning blade (removal means)
56 Brush (Adhesion reduction means)
68 Cleaning controller (control means)
72 1st conveyance path (collection means)
74 Screw conveyor (collection means)
80 Motor actuator (recovery means)
86 Second transport path (collection means)
88 Screw conveyor (collection means)
92 Motor actuator (collection means)
96 3rd transport path (collection means)
108 Motor actuator (recovery means)
136 Fourth transport path (collection means)
138 Shutter (collection means)
140 Solenoid (collection means)

Claims (2)

The toner image corresponding to the electrostatic latent image is transferred to the image bearing member on which the electrostatic latent image is formed on the outer peripheral surface by rotating or moving within a predetermined range. An image forming apparatus formed on an outer peripheral surface of a body and transferring the toner image onto a transfer medium,
The electrostatic latent image is provided on the outer peripheral surface of the image carrier based on the image information provided on the upstream side of the developing means along the rotational direction or the moving direction of the image carrier. An electrostatic latent image forming unit that forms an electrostatic latent image for forming a toner band on the outer peripheral surface of the image carrier at a predetermined timing.
The image is provided downstream of the transfer position for transferring the toner image to the transfer medium with respect to the transfer medium in the rotational direction or the moving direction of the image carrier, and is in contact with the outer peripheral surface of the image carrier. Removing means for scraping off the toner adhering to the outer peripheral surface of the carrier;
A collecting unit that collects the toner scraped off by the removing unit and supplies only the toner scraped off by the removing unit to the developing unit at a predetermined timing when the toner band is formed;
An image forming apparatus comprising: Provided to be movable toward and away from the outer peripheral surface of the image carrier between the contact position of the removing means with respect to the image carrier and the transfer position, and close to the outer peripheral surface of the image carrier. An adhesion reducing means for reducing the adhesion of the toner by contacting the toner attached to the outer peripheral surface of the image carrier;
The adhesion reducing means is separated from the outer peripheral surface of the image carrier at a predetermined timing when the electrostatic latent image forming means forms the electrostatic latent image for forming the toner band on the image carrier. Control means;
The image forming apparatus according to claim 1, further comprising:

Images