JP2006098853A - Development cartridge and image forming apparatus using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply and effectively correct deflection of a developing roller due to push pressure of a pressure contact member while obtaining high image quality by lessening a developing gap as much as possible. <P>SOLUTION: A development cartridge 1 is constituted as a photoreceptor development machine integrated cartridge integrating a photoreceptor 2 and a development machine 3. The photoreceptor 2 and the developing roller 5 are supported with the same support members 4a and 4b of a photoreceptor development machine integrated case 4. Sheet-like spacers 11 and 12 fixed on both the ends of the developing roller 5 are pressure contacted on the surface of the photoreceptor 2. Furthermore, a feed roller 6 is pressure contacted on the developing roller 5, and the photoreceptor 2 is pressure contacted oppositely or substantially oppositely in a direction of force F2' that pushes the developing roller. The deflection of the developing roller 5 due to pressure contact of the feed roller 6 is corrected to be returned by force F' of reaction of push pressure F2 due to pressure contact to the photoreceptor 2 of the developing roller 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as an electrophotographic apparatus, an electrostatic copying machine, a printer, and a facsimile machine, in which an image carrier such as a photosensitive member and a developing machine are integrally formed on a cartridge, and the image carrier and the developing roller A developing cartridge in which a non-contact jumping developing type developing machine having a predetermined developing gap is used, and a pressing member such as a toner supply roller or a toner regulating member is pressed against the developing roller, and image formation using the developing cartridge It relates to the technical field of equipment.

  Conventionally, many image forming apparatuses using a non-contact jumping development method are known as image forming apparatuses. In this non-contact jumping development method, a predetermined development gap is provided between a photosensitive member as an image carrier and a developing roller, and toner on the developing roller is jumped to the photosensitive member to electrostatic latent image on the photosensitive member. This is a method of developing. In this non-contact jumping development method, it is required to maintain a development gap between the photosensitive member and the development roller with high accuracy in order to perform good development.

  Therefore, conventionally, a spacer made of a roller having a larger radius than the developing roller is fitted to both ends of the developing roller as a developing gap adjusting member, and these rollers are brought into contact with the outer peripheral surface of the photosensitive member, whereby the photosensitive member and the developing roller are (See, for example, Patent Document 1).

  By the way, in such a conventional non-contact jumping development type image forming apparatus, a supply roller, a regulating blade, and the like are used to charge the toner or to form a uniform thin toner layer on the developing roller. The pressure contact member is pressed. For this reason, since a bending moment acts on the developing roller by the pressing force of these pressure contact members, the central portion of the developing roller bends toward the photosensitive member, and the developing gap fluctuates to maintain a predetermined developing gap. Can not be. In order to fully exhibit the functions of the supply roller and the regulating blade, a force of about 1 kgf is required as a contact force of these pressure contact members to the developing roller, so that the developing roller bends several tens of μm. If the predetermined development gap cannot be maintained as described above, not only a difference in density occurs between the both ends and the center of the photosensitive member, but also vibration due to deflection caused by the rotation of the developing roller. Occurs, resulting in a banding image, which makes it impossible to obtain a high-quality image.

  For this reason, in the image forming apparatus disclosed in Patent Document 1, the central portion of the developing roller or the central portion of the photosensitive member is formed in a concave shape or a convex shape so that, for example, the developing roller is pressed by the pressing force of the supply roller. A predetermined developing gap can be maintained even if the photosensitive member is bent.

  On the other hand, when a roller is used as the developing gap adjustment member, an appropriate developing gap is ensured between the developing roller and the photosensitive member by overlapping errors such as the coaxiality between the roller and the developing roller and the roundness of the roller. Difficult to do. In addition, in order to obtain high image quality in the non-contact jumping development method, it is necessary to narrow the development gap. However, since the roller has a certain thickness, the roller gap is formed very thin to narrow the development gap. Difficult to do.

Therefore, a sheet-like member is used as the developing gap adjusting member, and this sheet-like member is interposed between the outer peripheral surface of both ends of the developing roller and the outer peripheral surface of both ends of the photosensitive member, thereby providing a gap between the developing roller and the photosensitive member. It has been proposed that a proper development gap can be easily secured (see, for example, Patent Document 2). In that case, the developing roller and the photosensitive member are supported by different support members. According to the image forming apparatus disclosed in Patent Document 2, it is possible to solve the problem in the case where a roller is used as the developing gap adjusting member.
JP-A-6-258933. Japanese Patent Laid-Open No. 5-27571.

  By the way, in the image forming apparatus disclosed in Patent Document 1 described above, it is necessary to form the central portion of the developing roller or the central portion of the photoreceptor in a concave shape or a convex shape. In that case, on the outer peripheral surface of the developing roller or the photoreceptor, the depth of the recess or the height of the protrusion at the center with respect to both end portions is extremely small, such as several tens of μm, corresponding to several tens of μm of the deflection amount of the developing roller. A concave curved surface or a convex curved surface is formed. Thus, for example, when the central portion of the developing roller is to be formed in a concave shape or a convex shape, there is the following problem, that is, the width of the normal developing roller is several tens of centimeters, and this is expressed in μm units. And tens of thousands of μm. For this reason, an extremely small concave surface or convex surface of several tens of μm must be processed on a member having an extremely long length of several tens of thousands of μm. The cost will be very high. In addition, it is extremely difficult to process the outer peripheral surface of the developing roller over the entire surface to have the same surface roughness and the same electric resistance by processing. Such a problem also occurs when the central portion of the photoreceptor is formed in a concave shape or a convex shape.

  Further, Patent Document 2 does not disclose or suggest that the predetermined developing gap cannot be maintained because the developing roller is bent toward the photosensitive member by the pressing force of a pressure contact member such as a supply roller or a regulating blade. However, the image forming apparatus disclosed in Patent Document 2 also has a problem that the developing roller 31 is bent toward the photosensitive member 33 by the pressing force of the supply roller 32 as shown in FIG. That is, the supply roller 32 rotatably supported by the same support member of the developing machine case 34 is pressed against the developing roller 31 rotatably supported by the support members 34a and 34b of the developing machine case 34 with a predetermined pressing force F1. Has been. On the other hand, for example, on the other support members 35 and 36 of the main body of the image forming apparatus different from the developing machine case 34, the photosensitive member 33 is a sheet-like spacer 37 and 38 fixed to the outer peripheral surfaces of both end portions of the developing roller 31. Is brought into contact with the outer peripheral surfaces of both end portions of the photosensitive member 33 so that a predetermined developing gap is formed between the photosensitive member 33 and the developing roller 31 so as to be rotatably supported. Then, when the supply roller 32 presses the developing roller 31 with a predetermined pressing force F1, the central portion of the developing roller 31 bends toward the photoconductor 33, and the development gap varies. In particular, when the development gap is reduced by using a sheet-like spacer as in Patent Document 2, the variation rate of the development gap increases due to such bending of the development roller. In particular, in the case of a development gap of 100 μm or less, the development gap fluctuation rate reaches several tens of percent. For this reason, the influence on the image quality of the development gap fluctuation due to the deflection of the developing roller is increased.

  Therefore, the image forming apparatus disclosed in Patent Document 2 is also required to suppress the fluctuation of the development gap. However, as disclosed in Patent Document 1 described above, the central portion of the developing roller disclosed in Patent Document 2 or photosensitive When the central part of the body is formed in a concave shape or a convex shape, the above-described problem occurs.

  The present invention has been made in view of such circumstances, and an object of the present invention is to form a cartridge integrated with an image carrier developing machine and to obtain a high image quality by making the developing gap as small as possible. It is another object of the present invention to provide an inexpensive developing cartridge and an image forming apparatus using the same that can easily and effectively correct the deflection of the developing roller due to the pressing force of the contact member.

  In order to solve the above-mentioned problems, the developing cartridge according to the first aspect of the present invention is provided with an image carrier and a toner transport surface provided so as to face the image carrier with a predetermined development gap therebetween. A developing cartridge having at least a developing roller that conveys toner to a body and a pressing member that is in pressure contact with the developing roller, wherein the image carrier and the developing machine are integrated into the cartridge; A sheet-like spacer is fixed to the outer peripheral surfaces of both ends of the image forming unit, and the development gap is formed between the image carrier and the developing roller by pressing the spacer against the outer peripheral surface of the image carrier. The pressing force of the image carrier pressing the developing roller by the press contact of the spacer to the image carrier is applied to the image bearing member and the developing roller. Wherein wherein the pressing member by pressure contact to the developing roller is supported by the same supporting member so as to face the pressing force for pressing the developing roller.

According to a second aspect of the present invention, the developing roller is formed of an elastic body and the spacer made of metal is fixed on the elastic body, or the developing roller is formed of a metal roller and the metal The spacer made of an elastic body is fixed on a roller.
Further, the developing cartridge of the invention of claim 3 is characterized in that the developing roller is formed of a metal roller and the spacer made of a heat shrinkable tube is fixed on the metal roller.

Further, in the developing cartridge of the invention of claim 4, the pressure contact member is brought into pressure contact with the development roller to supply toner to the development roller, or is pressed against the development roller and conveyed to the image carrier. It is a regulating member that regulates toner on the developing roller.
Furthermore, the developing cartridge of the invention of claim 5 is characterized in that the peripheral speed of the outer peripheral surface of the image carrier and the peripheral speed of the outer peripheral surface of the spacer are set to be the same or substantially the same. To do.

  Furthermore, an image forming apparatus according to a sixth aspect of the present invention comprises at least a developing cartridge in which the image carrier and the developing device are integrated into a cartridge, and the developing cartridge is an image forming apparatus that performs non-contact jumping development. 5. The developing cartridge according to any one of 1 to 4,

  According to the developing cartridge of the present invention configured as described above, the pressing force by which the image carrier presses the developing roller by the pressure contact of the spacer fixed on the developing roller to the image bearing member, the supply roller, the regulating member, or the like Since the pressure contact member opposes the pressing force that presses the development roller by the pressure contact of the pressure contact member to the development roller, the deflection of the development roller caused by the pressure contact member being pressed against the development roller is suppressed and corrected. Will be able to. In that case, in the developing cartridge of the present invention, since the image carrier and the developing roller are supported by the same support member as an integral cartridge of the image carrier and the developing device, the image is supported by the pressure contact of the developing roller to the image carrier. As the pressing force with which the carrier presses the developing roller, a large pressing force sufficient to return the bending of the developing roller due to the pressing of the pressing member can be obtained. As a result, it is possible to more effectively suppress and correct the deflection of the developing roller caused by the pressing member being pressed against the developing roller.

  Further, since a sheet-like spacer is used as a member for adjusting the developing gap between the image carrier and the developing roller, the coaxiality of the spacer with respect to the developing roller can be stably improved, and the developing gap can be made as small as possible. In addition, since the fulcrum when the pressing force that the image carrier presses the developing roller is applied to both ends of the developing roller becomes a relatively wide surface, it is possible to easily correct the deflection of the developing roller itself, Since the tolerance of the development gap is determined by the thickness of the spacer, the accuracy of the development gap can be improved. Thereby, a good image with high image quality can be obtained.

  Further, as disclosed in the above-mentioned Patent Document 1, it is not necessary to form the central portion of the developing roller or the central portion of the image carrier in a concave shape or a convex shape. This eliminates the need for special processing that requires high accuracy, reduces the cost of the developing roller, and makes it easy to make the outer peripheral surface of the developing roller have the same surface roughness and the same electrical resistance over the entire surface. Can be. In particular, since no special processing is required, a conventional developing roller can be used as it is.

  In particular, according to the developing cartridge of the second aspect of the invention, the developing roller is formed of an elastic body and a metal spacer is fixed on the elastic body, or the developing roller is formed of a metal roller and the metal roller. Since the sheet-like spacer having elasticity is fixed on the upper surface, even if the developing roller is bent or shaken, the generated vibration can be reduced and the banding image can be hardly generated. it can.

  According to the developing cartridge of the third aspect of the present invention, the heat shrinkable tube is used as the spacer as the developing gap adjusting member. However, since the heat shrinkable tube is seamless and elastic, By combining organically with the structure of the developing cartridge described above, the effects of claims 1 and 2 described above can be more fully exhibited. In addition, by using a heat-shrinkable tube as the spacer, the spacer can be easily fixed to the developing roller, and a highly accurate developing gap can be easily set.

  Further, according to the developing cartridge of the fifth aspect of the invention, the peripheral speed of the outer peripheral surface of the image carrier and the peripheral speed of the outer peripheral surface of the spacer on the developing roller are set to be the same or substantially the same. It is possible to reduce the friction at the press-contact portion between the body and the spacer on the developing roller to suppress heat generation, to suppress both the spacer and the image carrier from being worn, and to suppress the development gap fluctuation due to frictional vibration. .

  Further, according to the image forming apparatus of the invention of claim 6, even if a pressure contact member such as a supply roller or a regulating member is pressed against the developing roller using the developing cartridge according to any one of claims 1 to 4, Since it is possible to reliably maintain a predetermined development gap by suppressing fluctuations in the development gap between the image carrier and the developing roller, highly accurate non-contact jumping development can be performed, and high image quality is excellent. An image can be obtained.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 schematically shows an example of an embodiment of a developing cartridge according to the present invention, where (a) is a cross-sectional view, (b) is a partial view of the developing cartridge of this example, and FIG. 2 is shown in FIG. It is a figure which shows the support state of the image carrier of an example, a developing roller, and a supply roller.

As shown in FIGS. 1A and 1B, the developing cartridge 1 of this example includes an image carrier (in this example, composed of a photosensitive member 2; hereinafter, described as the photosensitive member 2) and a developing device 3. It is configured as an integrated image carrier developing unit integrated cartridge (in this example, a photosensitive unit integrated cartridge).
As shown in FIG. 2, the rotating shafts 2a and 2b projecting from both ends of the photosensitive member 2 are rotatably supported by supporting members 4a and 4b constituting the photosensitive member developing machine integrated case 4, respectively.

  As shown in FIGS. 1A and 1B, the developing machine 3 includes a developing roller 5 that conveys the toner T to the photoreceptor 2, a supply roller 6 that is pressed against the developing roller 5 and supplies the toner T, and a developing roller. A regulating blade 7 that regulates the toner T that is pressed against 5 and conveyed to the photosensitive member 2, a toner agitating / conveying member 8 that agitates and conveys the toner T, and a toner roller that receives the toner T conveyed by the toner agitating / conveying member 8. 6 is provided with a toner receiving member 9 for guiding the toner 6 and an upper seal 10 for preventing toner leakage while contacting the developing roller 5 in a direction for 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 machine integrated case 4.

  As shown in FIG. 2, the rotating shafts 5a and 5b protruding from both ends of the developing roller 5 are the same supporting members 4a and 4b as the supporting members 4a and 4b that support the rotating shafts 2a and 2b of the photosensitive member 2, respectively. Is rotatably supported. Sheet-like spacers 11 and 12 are fixed to the toner non-conveying surfaces 5c and 5d at both ends of the developing roller 5, respectively. These spacers 11 and 12 are brought into pressure contact with the image non-carrying surfaces 2c and 2d of the photosensitive member 2, whereby the toner carrying surface 5e of the developing roller 5 and the image carrying surface 2e of the photosensitive member 2 facing the toner carrying surface 5e. A development gap g is formed between the two.

  The developing gap g is adjusted to a desired size by appropriately selecting the thicknesses of the spacers 11 and 12. As a result, the developing machine 3 performs non-magnetic one-component developer non-contact jumping development using the toner T which is a non-magnetic one-component developer. In this case, in the image carrier / developer integrated cartridge 1 of this example, the photosensitive member 2 rotates clockwise as shown in FIG. 1B, and both the developing roller 5 and the supply roller 6 rotate counterclockwise. It is set to be. The peripheral speed of the photosensitive member 2 and the peripheral speed of the spacers 11 and 12 on the developing roller 5 are set to be the same or substantially the same.

The spacers 11 and 12 are pressed against the photosensitive member 2 by the pressing force F2 applied to the rotating shafts 5a and 5b of the developing roller 5 by the supporting members 4a and 4b. This is done by pressing the In this case, the pressing force F2 is the same between the support position center of the rotation shafts 2a and 2b of the photosensitive member 2 and the support position center of the rotation shafts 5a and 5b of the developing roller 5 on the same support member 4a and 4b. Is set smaller than the sum of the radius of the outer peripheral surface of the photosensitive member 2 and the radius of the outer peripheral surfaces of the spacers 11 and 12 on the developing roller 5. At this time, the photosensitive member 2 and the developing roller 5 are supported by the same supporting members 4a and 4b, so that the pressing force F2 is larger than that in the case where the photosensitive member 2 and the developing roller 5 are supported by different supporting members. Can be.
Further, the photosensitive member 2 presses the developing roller 5 through the spacers 11 and 12 by the pressing force F2 ′, which is a reaction of the pressing force F2 that the developing roller 5 presses the photosensitive member 2 through the spacers 11 and 12. Become. This pressing force F2 'has the opposite direction and the same magnitude as the pressing force F2.

For the developing roller 5, a metal roller such as iron having extremely small stress shrinkage and thermal shrinkage is used, and spacers 11 and 12 fixed on the metal roller are elastic spacers. . As an elastic body used for the spacer, a plastic or rubber such as fluororesin, polyester, polyolefin, polyimide, epoxy, acetate, silicone, acrylic, rubber, etc. can be used, and in that case, an insulator is preferable. And as the spacers 11 and 12 which consist of such an elastic body, an adhesive tape may be sufficient and a seamless heat-shrinkable tube may be sufficient.
In addition, an elastic roller made of an elastic body can be used as the developing roller 5, and in this case, a material that has a very small stress contraction or thermal contraction such as metal or ceramics is used as a spacer fixed to the elastic roller. preferable.

  The rotating shafts 6a and 6b protruding from both ends of the supply roller 6 are also the same supporting members 4a and 4b as the supporting members 4a and 4b for supporting the rotating shafts 2a and 2b of the photosensitive member 2 and the rotating shafts 5a and 5b of the developing roller 5, respectively. , 4b is rotatably supported and is in pressure contact with the developing roller 5. In this case, as shown in FIG. 1B, the supply roller 6 is pressed against the developing roller 5 at a position opposite to or substantially opposite to the position where the developing roller 5 is pressed against the photosensitive member 2 and the center of the developing roller 5. Yes. Therefore, the direction of the pressing force F <b> 2 ′ in which the photosensitive member 2 presses the developing roller 5 and the direction of the pressing force F <b> 1 in which the supply roller 6 presses the developing roller 5 are opposed or substantially opposed.

  In the developing cartridge 1 of this example configured as described above, the photosensitive member 2 and the developing roller 5 are supported by the same supporting members 4a and 4b, and the toner non-conveying surfaces 4c and 4d at both ends of the developing roller 5 are supported. The fixed spacers 11 and 12 are pressed against the image non-carrying surfaces 2c and 2d of the photosensitive member 2, respectively, and the supply roller 6 is opposed to the developing roller 5 in the direction of the pressing force F2 of the developing roller 5 by the photosensitive member 2. Alternatively, since the pressing roller F is pressed substantially opposite to the developing roller 5, the developing roller 5 is bent by the pressing force F <b> 2 that presses the developing roller 5 against the photosensitive member 2. Will come back.

  More specifically, since the supply roller 6 is pressed against the developing roller 5 with the pressing force F1 as in the case shown in FIG. 3, a bending moment acts on the developing roller 5, so that the developing roller 5 of the toner conveying surface 5e bends to the same side as the direction of the pressing force F1. Further, as shown in FIG. 2, in order to press the spacers 11 and 12 on the developing roller 5 against the photosensitive member 2, the rotating shafts 5a and 5b at both ends of the developing roller 5 are pressed toward the photosensitive member 2 with a pressing force F2. Will be pressed. For this reason, the photosensitive member 2 presses the developing roller 5 by the pressing force F2 'which is the reaction of the pressing force F2, and a bending moment acts on the developing roller 5, so that the toner conveying surface 5e of the developing roller 5 is applied. Is bent to the same side as the direction of the pressing force F2 ′. Since the direction of the pressing force F2 'and the direction of the pressing force F1 are opposed or substantially opposed to each other, the bending of the developing roller 5 due to the pressing force F1 is returned by the bending of the developing roller 5 due to the pressing force F2'.

  Accordingly, it is possible to perform correction so as to suppress the bending of the developing roller 5 caused by the supply roller 6 being pressed against the developing roller 5. In particular, in the developing cartridge 1 of this example, the photosensitive member 2 and the developing roller 3 are supported by the same supporting members 4a and 4b as an integral cartridge of the photosensitive member 2 and the developing device 3, so that the pressing force F2 'is It is possible to obtain a relatively large force for returning the bending of the developing roller 5 due to the pressure contact of the supply roller 6. Thereby, the bending of the developing roller 5 caused by the supply roller 6 being pressed against the developing roller 5 can be more effectively suppressed and corrected.

  Further, as disclosed in the aforementioned Patent Document 1, it is not necessary to form the central portion of the developing roller 5 or the central portion of the photosensitive member 2 in a concave shape or a convex shape. On the other hand, it becomes unnecessary to perform special processing that requires high accuracy, and the cost of the developing roller 5 or the photosensitive member 2 can be reduced, and the outer peripheral surface of the developing roller 5 or the photosensitive member 2 is covered over the entire surface. The same surface roughness and the same electrical resistance can be easily achieved. In particular, since no special processing is required, a conventional one can be used as it is as the developing roller 5 or the photoreceptor 2.

  Further, since the sheet-like spacers 11 and 12 are used as members for adjusting the developing gap g between the photosensitive member 2 and the developing roller 5, the pressing force F 2 is applied to the rotating shafts 5 a and 5 b at both ends of the developing roller 5. In addition, since the fulcrum with which the spacers 11 and 12 abut against the photosensitive member 2 have a relatively wide surface, the deflection of the developing roller 5 itself can be easily corrected, and the tolerance of the developing gap g can be increased. Therefore, the accuracy of the development gap g can be improved.

  Further, since the peripheral speed of the outer peripheral surface of the photosensitive member 2 and the peripheral speed of the outer peripheral surfaces of the spacers 11 and 12 on the developing roller 5 are set to be the same or substantially the same, the spacer on the photosensitive member 2 and the developing roller 5 is set. The friction between the pressure contact portions 11 and 12 can be reduced to suppress heat generation, and the wear of the photoreceptor 2 and the spacers 11 and 12 can be suppressed together, and the development gap fluctuation due to frictional vibration can be suppressed.

  Further, the developing roller 5 is formed of an elastic body and metal spacers 11 and 12 are fixed on the elastic body, or the developing roller 5 is formed of a metal roller and elastic spacers are formed on the metal roller. Since 11 and 12 are fixed, even if the developing roller 5 is bent or shaken as described above, the generated vibration can be alleviated and the banding image can be hardly generated.

  In particular, it is preferable to use heat shrinkable tubes as the spacers 11 and 12. Since this heat-shrinkable tube is seamless and elastic, it can sufficiently exhibit the above-described effects and is suitable as a developing gap adjusting member, and can be fixed to the developing roller 5 relatively easily.

  By using the developing cartridge 1 of this example in an image forming apparatus that performs non-contact development using non-magnetic one-component toner, even if the supply roller 6 is pressed against the developing roller 5, the photosensitive member 2 and the developing roller 5 It is possible to reliably maintain the predetermined development gap g by suppressing fluctuations in the development gap g during this time, so that high-precision non-contact jumping development can be performed, and a high-quality image can be obtained. .

Next, examples and comparative examples of the present invention will be described.
Example 1
In Example 1, the developing cartridge 1 which is the photosensitive member integrated cartridge shown in FIG. 1 was used. At this time, an iron metal roller having a diameter of 18 mm and a length of 290 mm was used for the developing roller 5, and a PFA heat shrinkable tube having a thickness of 60 μm was used for the sheet-like spacers 11 and 12. Further, the contact force F1 of the supply roller 6 to the developing roller 5 was set to 2 kgf, and the contact force F2 of the developing roller 5 to the photosensitive member 2 was set to 4 kgf. The deflection of the developing roller 5 measured at this time was 7 μm in terms of the difference between both end portions and the central portion.

(Example 2)
In Example 2, the developing cartridge 1 which is the photosensitive member developing device integrated cartridge shown in FIG. 1 is used. At this time, an iron metal roller having a diameter of 18 mm and a length of 290 mm was used for the developing roller 5, and a PFA heat shrinkable tube having a thickness of 80 μm was used for the sheet-like spacers 11 and 12. Further, the contact force F1 of the supply roller 6 to the developing roller 5 was set to 2 kgf, and the contact force F2 of the developing roller 5 to the photosensitive member 2 was set to 6 kgf. The deflection of the developing roller 5 measured at this time was 3 μm in terms of the difference between both end portions and the central portion.

(Example 3)
In Example 3, the developing cartridge 1 which is the photosensitive member developer integrated cartridge shown in FIG. 1 is used. At this time, a conductive rubber roller having a diameter of 18 mm and a length of 290 mm was used for the developing roller 5, and an aluminum tube having a thickness of 80 μm was used for the sheet-like spacers 11 and 12. Further, the contact force F1 of the supply roller 6 to the developing roller 5 was set to 2 kgf, and the contact force F2 of the developing roller 5 to the photosensitive member 2 was set to 4 kgf. The deflection of the developing roller 5 measured at this time was 4 μm in terms of the difference between both end portions and the central portion.

(Comparative Example 1)
In Comparative Example 1, a developing cartridge having a spacer different from that of the developing cartridge 1 which is also a photosensitive developer integrated cartridge shown in FIG. 1 was used. At this time, instead of a sheet-like spacer, a roller installed on the shaft of the developing roller was used as the developing gap adjusting member. Further, an iron metal roller having a diameter of 18 mm and a length of 290 mm was used as the developing roller 5, and the developing gap g between the photoreceptor 2 and the developing roller 5 was set to 80 μm. Further, the contact force F1 of the supply roller 6 to the developing roller 5 was set to 2 kgf, and the contact force F2 of the developing roller 5 to the photosensitive member 2 was set to 4 kgf. The deflection of the developing roller 5 measured at this time was 20 μm in terms of the difference between both end portions and the central portion. When a roller is used as the spacer, the roller cannot be installed on the developing roller 5 and is installed on a shaft that is narrower than the surface of the developing roller 5, so that the developing roller 5 bends more than the spacer.

(Comparative Example 2)
In Comparative Example 2, the photosensitive member 33 and the developing roller 31 were supported by different support members as shown in FIG. At this time, an iron metal roller having a diameter of 18 mm and a length of 290 mm was used for the developing roller 31, and a PFA heat shrinkable tube having a thickness of 60 μm was used for the sheet-like spacers 37 and 38. The contact force F1 of the supply roller 32 to the developing roller 32 was set to 2 kgf. Since the photosensitive member 33 and the developing roller 31 are supported by different supporting members, a large contact force F2 of the developing roller 31 to the photosensitive member 33 cannot be obtained, and the measurement result is 0.5 kgf. The deflection of the developing roller 31 measured at this time was 30 μm in terms of the difference between both end portions and the central portion. That is, since the contact force between the photosensitive member 33 and the developing roller 31 cannot be increased, the deflection of the developing roller 31 reaches half of the thickness of the spacers 37 and 38, that is, 60 μm of the developing gap g.

  From the results of Examples 1 to 3 and Comparative Examples 1 and 2 described above, when a roller is installed as the developing gap adjusting member on the shaft of the developing roller, or the photosensitive member 33 and the developing roller 31 are supported by different supporting members. In the case where the cartridge is not a photosensitive developer integrated cartridge, the deflection of the developing roller 31 due to the pressure contact of the supply roller 32 to the developing roller 31 cannot be effectively corrected. Sheet-like spacers 11 and 12 are fixed as gap adjusting members, and the photosensitive member 2 and the developing roller 5 are connected to the same supporting member 4a, so that the spacers 11 and 12 on the developing roller 5 are pressed against the photosensitive member 2. When supported by 4b, it was confirmed that the deflection of the developing roller 5 due to the pressure contact of the supply roller 6 to the developing roller 5 can be effectively corrected.

  In the above-described example, the developing cartridge of the present invention is applied to the developing cartridge 1 in which the pressing member pressed against the developing roller 5 is the supply roller 6. However, in the developing cartridge of the present invention, the pressing member is The present invention can also be applied to the developing cartridge 1 that is a regulating member such as a regulating blade 7 that regulates the toner T that contacts the developing roller 5 and is conveyed to the photoreceptor 2.

  The developing cartridge and the image forming apparatus of the present invention are an image forming apparatus for forming an electrostatic latent image on an image carrier such as an electrophotographic, electrostatic copying machine, printer, facsimile, etc. And a non-contact jumping development type developing machine having a predetermined development gap between the image carrier and the developing roller, and a pressure contact member such as a toner supply roller or a toner regulating member Can be suitably used for a developing cartridge in pressure contact with the developing roller and an image forming apparatus using the same.

BRIEF DESCRIPTION OF THE DRAWINGS An example of embodiment of the developing cartridge concerning this invention is shown typically, (a) is a cross-sectional view, (b) is a partial view of the developing cartridge of this example. It is a figure which shows the support state of the image carrier of the example shown in FIG. 1, a developing roller, and a supply roller. It is a figure explaining the behavior of the conventional developing roller by the pressure contact of a supply roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Developer cartridge, 2 ... Photoconductor (image carrier), 2a, 2b ... Rotating shaft of photoconductor, 3 ... Developer, 4 ... Photoconductor developer integrated case, 4a, 4b ... Support member, 5 ... Developer roller 5a, 5b ... rotating shaft of developing roller, 6 ... supply roller, 6a, 6b ... rotating shaft of supply roller, 7 ... regulating blade, 11, 12 ... spacer

Claims (6)

An image carrier, a developing roller provided with a toner conveyance surface facing the image carrier with a predetermined development gap therebetween, and a toner that conveys toner to the image carrier, and a pressure contact member that is in pressure contact with the development roller A developing cartridge comprising at least a developing machine having the image carrier and the developing machine as an integral cartridge,
The sheet-like spacers are fixed to the outer peripheral surfaces of both ends of the developing roller, and the developer is pressed against the outer peripheral surface of the image carrier, whereby the development is performed between the image carrier and the developing roller. Forming a gap,
The pressing member presses the image bearing member and the developing roller against the developing roller by the pressing force of the pressing member against the developing roller by the pressing force of the image bearing member against the developing roller when the spacer is pressed against the image bearing member. Is supported by the same support member so as to face the pressing force for pressing the developing roller. The developing roller is formed of an elastic body and the spacer made of metal is fixed on the elastic body, or the developing roller is formed of a metal roller and the spacer made of an elastic body is fixed on the metal roller. The developing cartridge according to claim 1. 2. The developing cartridge according to claim 1, wherein the developing roller is formed of a metal roller, and the spacer made of a heat shrinkable tube is fixed on the metal roller. The pressing member is a supply roller that is pressed against the developing roller to supply toner to the developing roller, or a regulating member that regulates toner on the developing roller that is pressed against the developing roller and conveyed to the image carrier. 4. The developing cartridge according to claim 1, wherein the developing cartridge is provided. 5. The peripheral speed of the outer peripheral surface of the image carrier and the peripheral speed of the outer peripheral surface of the spacer are set to be the same or substantially the same. Developer cartridge. In an image forming apparatus comprising at least a developing cartridge in which the image carrier and the developing device are integrated into a cartridge, and performing non-contact jumping development,
The image forming apparatus according to claim 1, wherein the developing cartridge is a developing cartridge according to claim 1.

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