JP4743398B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to the technical field of image forming apparatuses such as electrophotography, electrostatic copying machines, printers, facsimiles and the like, and in particular, non-contact jumping development type images having a predetermined development gap between an image carrier and a developing roller. The present invention relates to a forming apparatus.

  Conventionally, a non-contact jumping development method is known as an image forming apparatus. In this non-contact jumping development type image forming apparatus, a predetermined development gap is provided between a photosensitive member as an image bearing member and a developing roller, and toner on the developing roller is jumped to the photosensitive member to be formed on the photosensitive member. This is a method for developing an electrostatic latent image. In this non-contact jumping development system, it is important to maintain a high development gap between the photosensitive member and the development roller for good development.

As a conventional technique for maintaining the developing gap between the photosensitive member and the developing roller with high accuracy, Japanese Patent Laid-Open No. 5-27571 (conventional example 1) uses a sheet-like member as a developing gap adjusting material. A technique is disclosed in which a member is interposed between the outer peripheral surfaces of both ends of the developing roller and the outer peripheral surfaces of both ends of the photosensitive member to easily ensure an appropriate developing gap between the developing roller and the photosensitive member. . Japanese Patent Laid-Open No. 2001-296723 (conventional example 2) wraps and fixes film members around the outer peripheral surfaces of both ends of a charging roller, and abuts an image carrier on these film members to charge the charging roller. A technique for performing proximity charging by providing a predetermined charging gap between the image carrier and the image carrier is disclosed.
JP-A-5-27571 JP 2001-296723 A

  However, in the conventional example 1, since the development gap adjusting material is provided in a place different from the photosensitive member and the developing roller, the assembly of the photosensitive member, the developing roller and the developing gap adjusting material is not only troublesome. Depending on the assembled state, it becomes difficult to set the development gap with high accuracy. In addition, since the developing gap adjusting material is fixed, the photosensitive member and the developing roller rotate, so that the developing gap adjusting material and the photosensitive member and the developing gap adjusting material and the developing roller rub against each other. As a result, the photoconductor and the developing roller are worn, making it difficult to maintain a high-precision developing gap.

  It is also conceivable to apply the charging gap adjusting material of Conventional Example 2 to the developing gap adjusting material to maintain the developing gap with high accuracy. However, the charging roller does not require a high driving torque, but the developing roller charges and supplies the toner by abutting and rubbing the supply roller and the regulating blade. Is likely to occur. Further, when the charging gap adjusting material is applied to the developing roller, the developing gap can be ensured with higher accuracy than the roller-shaped gap adjusting material, but the vibration of the developing roller is easily transmitted directly to the photoconductor, Driving vibrations and vibrations on the contact surface of the photosensitive member affect the development gap and toner development, causing a problem that banding images tend to appear on the image surface. Further, when the development roller and the photosensitive member are driven differently, there arises a problem that the development gap adjusting material tends to be stretched or vibrated in the circumferential direction.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that solves the problems of the prior art and that can maintain a developing gap with high accuracy and obtain a good image with reduced vibrations.

In order to solve the above-described problems, the image forming apparatus of the present invention is provided with an image carrier and a toner conveyance surface so as to face each other with a predetermined development gap therebetween, and toner is applied to the image carrier. A developing roller to be transported, and a spacer that is disposed at the end of the peripheral surface of the developing roller and maintains a developing gap. The spacer includes a lower adhesive layer and vibration damping layer and an upper base material layer that are integrated. A tape-like shape, the image carrier and the developing roller are driven separately, and a cut is formed at the same position in the circumferential direction of the base material layer and the adhesive layer / damping layer of the spacer. The width of the cut is wider than that of the base material layer .

An image forming apparatus according to the present invention includes an image carrier, a developing roller that is provided so that a toner conveyance surface faces the image carrier with a predetermined development gap, and conveys toner to the image carrier; A spacer disposed at the end of the peripheral surface of the developing roller to maintain a development gap, and the spacer is in the form of a tape in which a lower adhesive layer and vibration damping layer and an upper base material layer are integrated, The image bearing member and the developing roller are driven separately, and the cut positions in the circumferential direction of the base material layer and the adhesive layer / damping layer of the spacer are shifted.

The image forming apparatus of the present invention is characterized in that the cut of the base material layer is inclined.

The image forming apparatus of the present invention is characterized in that the spacer mounting portion of the developing roller is made of metal.

The image carrier of the present invention, a developing roller provided with a toner transport surface facing the image carrier with a predetermined development gap therebetween, and transporting toner to the image carrier, and a peripheral edge of the developing roller And a spacer that maintains the development gap, and the spacer has a two-layer structure in which the adhesive layer and damping layer is the lower layer and the base material layer is the upper layer, so that the lower adhesive layer and damping layer is The vibration of the developing roller is suppressed, the attachment to the developing roller is facilitated by excellent adhesiveness, and the upper base material layer secures the hardness as the gap spacer, so that a highly accurate developing gap can be secured.
By making the thickness of the pressure-sensitive adhesive layer / damping layer thinner than the thickness of the base material layer, the amount of compressive deformation of the pressure-sensitive adhesive layer / damping layer is suppressed, and the development gap can be secured with high accuracy.
With the configuration in which the spacer is in the form of a tape in which the adhesive layer / vibration control layer and the base material layer are integrated, the spacer can be easily attached to the developing roller.
The image carrier and the developing roller are driven separately, and the image carrier and the developing roller are driven separately, and a slit is formed at the same position in the circumferential direction of the base material layer of the spacer and the adhesive layer / damping layer. The width of the adhesive layer and the damping layer is wider than the width of the base layer, and when the photosensitive member and the developing roller are driven separately by a tape spacer, the tape seam occurs due to the occurrence of circumferential expansion and contraction. However, the band width of the adhesive layer and damping layer is wide, so that the base layer breaks into the adhesive layer and damping layer, creating a smooth recess. Less noticeable.
With the configuration in which the circumferential cut positions of the base material layer and the adhesion layer / damping layer of the spacer are shifted, the cut lines are less noticeable and peeling due to friction can be prevented.
With the configuration in which the cut line of the base material layer is in an oblique direction, the cut line is less noticeable and peeling due to friction can be prevented.
With the configuration in which the spacer mounting portion of the developing roller is made of metal, it is possible to suppress an increase in the temperature of the damping material that converts spacer vibration into heat energy.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a developing cartridge integrally formed with a developing device and a photoreceptor used in an example of an embodiment of an image forming apparatus according to the present invention, and FIG. 2 is a partial view of the developing cartridge.

  As shown in FIGS. 1 and 2, the developing cartridge 1 of the image forming apparatus of the present invention is an image carrier (in this example, the photosensitive member 2, and hence the “photosensitive member 2”) and the developing device 3. Are integrated as a photosensitive member-developing device integrated cartridge.

  The developing device 3 includes a developing roller 5 that conveys the toner T to the photosensitive member 2, a supply roller 6 that is pressed against the developing roller 5 to supply the toner T, and a toner T that is pressed against the developing roller 5 and conveyed to the photosensitive member 2. A regulating blade 7 that regulates toner, a toner agitating / conveying member 8 that agitates and conveys toner T, a toner receiving member 9 that receives toner T conveyed by the toner agitating / conveying member 8 and guides it toward the supply roller 6, and development An upper seal 10 is provided to prevent toner leakage while contacting the roller 5 in the direction of collecting the toner T remaining after development. The photosensitive member 2, the developing roller 5, the supply roller 6, the regulating blade 7, the toner stirring and conveying member 8, and the toner receiving member 9 are all disposed in the photosensitive member-developing device integrated case 4.

  As shown in FIG. 3, the photoreceptor 2 has an image carrying surface 2a formed at the center thereof, and image non-carrying surfaces 2b and 2c formed at both ends thereof. Further, the developing roller 5 has a toner transport surface 5a formed at the center thereof, and toner non-transport surfaces 5b and 5c formed at both ends thereof.

  Spacers 11 and 12 are wound around and fixed to the peripheral surfaces of the toner non-conveying surfaces 5b and 5c of the developing roller 5. The spacers 11 and 12 are brought into pressure contact with the image non-carrying surfaces 2b and 2c of the photosensitive member 2, so that a development gap g is formed between the toner conveying surface 5a of the developing roller 5 and the image carrying surface 2a of the photosensitive member 2. It is formed.

  The developing gap g can be set to a desired size by appropriately selecting the thicknesses of the spacers 11 and 12. As a result, the developing device 3 performs non-contact jumping development using the toner T that is a non-magnetic one-component developer. In that case, as shown in FIG. 1, the photosensitive member 2 rotates clockwise, and both the developing roller 5 and the supply roller 6 rotate counterclockwise. The circumferential speed of the photosensitive member 2 and the circumferential speed of the spacers 11 and 12 on the developing roller 5 are set to be the same or substantially the same.

  Since the developing roller 5 charges and supplies the toner T by abutting and rubbing the supply roller 6 and the regulating blade 7 and the like, a high driving torque is required and vibration due to driving tends to occur. The vibration of the developing roller 5 is easily transmitted directly to the photosensitive member 2, which adversely affects the development gap g and the development of the toner T, and causes a problem that the image tends to appear as a banding image on the image surface.

  FIG. 4 is a schematic perspective view of the spacers 11 and 12 of the present invention for solving such a problem. The spacers 11 and 12 that are wound and fixed on the peripheral surfaces of the toner non-conveying surfaces 5b and 5c of the developing roller 5 have a two-layer structure in which the adhesive layer / vibration layer 13 is a lower layer and the base material layer 14 is an upper layer. It has become. The material of the adhesive layer / damping layer 13 is preferably butyl rubber, ethylene acrylic, norbornene, silicon gel, or acrylic that has high damping performance and is sticky. The material of the base layer 14 is a plastic or rubber such as fluororesin, polyester, polyolefin, polyimide, epoxy, acetate, silicone, acrylic, rubber, etc., which is not too soft and relatively hard to keep the development gap g accurate. And an insulator is preferable.

  The toner non-transport surfaces 5b and 5c, which are the attachment portions of the spacers 11 and 12 of the developing roller 5, are preferably made of metal. The heat energy generated from the damping material 13 that converts the vibration of the spacers 11 and 12 into heat energy escapes from the metal having high thermal conductivity, and the temperature rise of the spacers 11 and 12 is suppressed.

  5A to 5G are cross-sectional views illustrating how the spacers 11 and 12 are attached to the developing roller 5. The spacers 11 and 12 may be a tape in which the lower adhesive layer / damping layer 13 and the upper substrate layer 14 are integrated. By using the spacers 11 and 12 as tapes in which the upper and lower layers are integrated, it is easy to attach the developing roller 5 to the peripheral surfaces of the toner non-transport surfaces 5b and 5c.

  In the embodiment shown in FIG. 5 (A), the spacers 11 and 12 are heat-shrinkable tubes in which the adhesive layer / damping layer 13 and the base material layer 14 are integrated, and the periphery of the toner non-conveying surfaces 5b and 5c of the developing roller 5 is used. Seamless spacers 11 and 12 are formed by being inserted into the surface and heated. As in the embodiment shown in FIG. 5A, the thickness of the adhesive layer / damping layer 13 of the spacers 11 and 12 is made smaller than the thickness of the base material layer 14. By doing so, the amount of compressive deformation of the spacers 11 and 12 can be suppressed, and the development gap g can be secured with high accuracy. On the other hand, in the comparative example shown in FIG. 5G, since the thickness of the adhesive layer / damping layer 13 is made larger than the thickness of the base material layer 14, the amount of compressive deformation of the spacers 11 and 12 is large, and the development gap g is accurately determined. Can't hold well.

  As shown in FIG. 5B, when the spacers 11 and 12 are tapes, cuts 15 and 16 are formed in the adhesive layer / vibration control layer 13 and the base material layer 14. When the photosensitive member 2 and the developing roller 5 are driven separately, the spacers 11 and 12 tend to stretch or vibrate in the circumferential direction. However, the spacers 11 and 12 are the lower adhesive layer / vibration control layer 13 and the upper layer base. When the material layer 14 is integrated into a tape, it is possible to suppress them by the configuration of the cut 15 of the adhesive layer / damping layer 13 and the cut 16 of the base material layer 14.

  One example thereof will be described with reference to the embodiment shown in FIG. 5C and the comparative example shown in FIG. In the embodiment shown in FIG. 5C, the cut 15 of the adhesive layer / damping layer 13 and the cut 16 of the base material layer 14 are formed at the same position in the circumferential direction, and the cut 15 of the adhesive layer / damping layer 13 is formed. Is wider than the width of the cut 16 in the base material layer 14, so that the spacer 11 and 12 in the circumferential direction due to separate driving of the photosensitive member and the developing roller are expanded and contracted in the circumferential direction of the adhesive layer and damping layer 13. Since the width is wide, the cut 16 of the base material layer 14 falls into the cut 15 of the pressure-sensitive adhesive layer / damping layer 13 to form a smooth concave portion, so that banding is less noticeable. On the other hand, in the comparative example shown in FIG. 5F, the cut 15 of the adhesive layer / damping layer 13 and the cut 16 of the base material layer 14 are formed at the same position in the circumferential direction. Since the width of the cut 15 is narrower than the width of the cut 16 in the base material layer 14, the width of the cut 16 in the base material layer 14 is increased by contraction in the circumferential direction of the spacers 11 and 12 by separate driving of the photosensitive member 2 and the developing roller 5. As a result, excitement occurs and banding becomes noticeable.

  In the embodiment shown in FIG. 5D, the position of the cut 15 in the adhesive layer / damping layer 13 and the position of the cut 16 in the base material layer 14 are formed at different positions in the circumferential direction. By comprising in this way, the cut | interruption 16 of the base material layer 14 becomes inconspicuous, and the peeling by the friction of the spacers 11 and 12 is suppressed.

  In the embodiment shown in FIG. 5E, the position of the cut 15 in the adhesive layer / damping layer 13 and the position of the cut 16 in the base layer 14 are formed at different positions in the circumferential direction, and the cut 16 in the base layer 14 is formed. This direction is an oblique direction in which the spacers 11 and 12 are not easily peeled off by rotational friction. By comprising in this way, the cut | interruption 16 of the base material layer 14 becomes much less conspicuous, and the peeling by the friction of the spacers 11 and 12 is suppressed further.

  FIG. 6 is a sectional view of the entire apparatus showing the image forming apparatus of the present invention.

  In FIG. 6, a drum-shaped photoconductor 101 is rotationally driven by a driving source such as a motor (not shown). A charging means 102 such as a charging brush is disposed on the outer periphery of the photoconductor 101, and the surface of the photoconductor 101 is uniformly charged while rotating in contact with the photoconductor 101.

  The photosensitive member 101 having a uniformly charged surface is selectively scanned and exposed in accordance with, for example, yellow image information as a first color by a latent image forming unit 103 such as a line exposure head scanning optical system. An electrostatic latent image is formed.

  On the downstream side in the rotation direction of the photosensitive member 101 on which the electrostatic latent image is recorded, yellow, magenta, cyan, and black toners are respectively stored as developing agents. 105, 106, and 107 are arranged, and the formed yellow electrostatic latent image is developed only by the yellow developing means 104 in contact with the photosensitive member 101, whereby a yellow toner image is formed.

  An intermediate transfer belt 108 is disposed adjacent to the photoreceptor 101 on the downstream side in the rotation direction of the photoreceptor 101 on which the toner image is formed. The intermediate transfer belt 108 is supported by being wound around a driving roller 109 and a tension roller 111, and is driven at a slightly higher speed within 101% of the peripheral speed of the photoconductor 101.

  The primary transfer roller 113 is urged toward the photoconductor 101 via the intermediate transfer belt 108, and a high pressure (not shown) is provided at a primary transfer position where the intermediate transfer belt 108 is sandwiched between the photoconductor 101 and the primary transfer roller 113. By supplying a voltage from the power source to the primary transfer roller 113, the yellow toner image formed by the above-described procedure is transferred onto the surface of the intermediate transfer belt 108.

  The photosensitive member 101 having the yellow toner image transferred to the intermediate transfer belt 108 further rotates, and the toner remaining on the surface of the photosensitive member 101 is scraped off by the photosensitive member cleaner constituted by a cleaner blade or the like, so that the image can be formed again. It becomes.

  By repeating the same procedure for the second to fourth color images (magenta, cyan, and black), the four color toner images are sequentially superimposed and recorded on the intermediate transfer belt 108.

  When the superposition of the four color toner images on the intermediate transfer belt 108 is completed, the recording sheet is fed by the paper feed roller 120 and the pair of paper transport rollers 115 and 116, and the secondary transfer roller 118 is intermediately transferred in synchronization with this. The four-color toner images on the intermediate transfer belt 108 are collectively transferred to the recording sheet by contacting the backup roller via the belt 108 and applying a voltage from a high voltage power source (not shown) to the secondary transfer roller 118. . A cleaner 121 composed of a cleaner blade or the like is rotated and brought into contact with the intermediate transfer belt 108 after the secondary transfer by a clutch mechanism and a cam mechanism (not shown), and the toner remaining on the surface of the intermediate transfer belt 108 is scraped off. When the scraping is completed, the cleaner 121 rotates in the reverse direction and retracts.

  The recording sheet onto which the four color toner images have been transferred is nipped and conveyed while being heated and pressed by a fixing means 122 having a heat roller incorporating a heating means such as a halogen lamp to fix the toner image. The recording sheet on which the toner image is fixed is discharged to the outside of the apparatus by a pair of discharge rollers 123 and 124, and the color image recording is completed.

It is a figure which shows embodiment of this invention. It is a figure which shows embodiment of this invention. It is a figure which shows embodiment of this invention. It is a figure which shows embodiment of this invention. (A)-(G) It is a figure which shows embodiment of this invention. It is a figure which shows embodiment of this invention.

Explanation of symbols

1: developing cartridge, 2: photoconductor, 2a: image carrying surface, 2b: image non-carrying surface, 2c: image non-carrying surface, 3: developing device, 4: photoconductor-developing device integrated case, 5: developing roller, 5a: toner conveying surface, 5b: toner non-conveying surface, 5c: toner non-conveying surface, 6: supply roller, 7: regulating blade, 8: toner stirring and conveying member, 9: toner receiving material, 10: upper seal, 11: Spacer, 12: Spacer, 13: Adhesive layer / damping layer, 14: Base material layer, 15: Cut of adhesive layer / damping layer, 16: Cut of base material layer

Claims (4)

An image carrier;
A developing roller which is provided so that a toner conveying surface faces the image carrier with a predetermined development gap and conveys toner to the image carrier;
A spacer that is disposed at a peripheral end of the developing roller and maintains a developing gap;
With
The spacer is in the form of a tape in which the lower adhesive layer and damping layer and the upper base material layer are integrated, and the image carrier and the developing roller are driven separately, and the spacer base material layer and the adhesive layer An image forming apparatus , wherein a cut is formed at the same position in the circumferential direction of the vibration damping layer, and the width of the cut of the adhesive layer / damping layer is made wider than that of the base material layer . An image carrier;
  A developing roller which is provided so that a toner conveying surface faces the image carrier with a predetermined development gap and conveys toner to the image carrier;
  A spacer that is disposed at a peripheral end of the developing roller and maintains a developing gap;
  With
The spacer is in the form of a tape in which the lower adhesive layer and damping layer and the upper base material layer are integrated, and the image carrier and the developing roller are driven separately, and the spacer base material layer and the adhesive layer An image forming apparatus characterized in that the cut position in the circumferential direction of the cum damping layer is shifted. The image forming apparatus according to claim 2 , wherein the cut of the base material layer is in an oblique direction. The image forming apparatus according to any one of claims 1 to 3, characterized in that the spacer mounting portion of the developing roller and the metal.

Images