JP2006106260A - Image forming apparatus - Google Patents

Abstract

A developing gap is made as small as possible so as to obtain high image quality, while shortening the axial length of a developing roller and suppressing contamination of a spacer, thereby maintaining the developing gap with high accuracy.
A sheet-like spacer 8 is fixed to a toner non-conveying surface 4e of a developing roller 4a. When these spacers 8 are pressed against the photoreceptor 2, the developing roller 4 a is disposed opposite to the photoreceptor 2 with a development gap g. A peripheral surface seal 9 is provided so as to overlap the spacer 8 on the toner non-transport surface 4 e and the outer peripheral surface of the spacer 8. Therefore, the axial length of the developing roller 4a can be shortened, and the bending of the developing roller 4a can be suppressed. Thereby, the development gap can be maintained with high accuracy.
[Selection] Figure 2

Description

  The present invention relates to a technical field of an electrophotographic image forming apparatus such as an electrophotographic apparatus, an electrostatic copying machine, a printer, and a facsimile, and more particularly, non-contact jumping having a predetermined developing gap between an image carrier and a developing roller. The present invention relates to a technical field of an image forming apparatus that forms an image by developing an electrostatic latent image on an image carrier using a non-magnetic one-component toner by a developing method.

  2. Description of the Related Art Conventionally, as an image forming apparatus, many image forming apparatuses including a developing device using a non-contact jumping development method are known. 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 radius larger than that of the developing roller is provided as a developing gap adjusting member on a rotating shaft protruding from both ends of the developing roller, and these rollers are brought into contact with the outer peripheral surface of the photosensitive member to contact the photosensitive member. A developing gap with the developing roller is maintained (see, for example, Patent Document 1).

  However, when a roller is used as the developing gap adjustment member, errors such as the coaxiality of the roller and the developing roller and the roundness of the roller overlap, so that an appropriate developing gap is secured between the developing roller and the photosensitive member. 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). 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.

On the other hand, in a developing device in a conventional image forming apparatus, in order to prevent toner from spilling from both ends of the developing roller, the toner non-conveying surfaces at both ends of the developing roller are smoothed without blasting, and the toner A peripheral seal is provided on the non-transport surface. (For example, refer to Patent Document 3).
Japanese Patent Laid-Open No. 2003-270928. Japanese Patent Laid-Open No. 5-27571. JP2003-323407A.

  By the way, in the non-contact developing device, as disclosed in the above-mentioned Patent Document 2, sheet-like spacers are provided at both ends of the developing roller to narrow the developing gap to obtain high image quality and improve the accuracy of the developing gap. It is conceivable that toner can be prevented from spilling from both ends by means of peripheral surface seals provided at both ends of the developing roller as disclosed in Patent Document 3, while enabling improvement.

  However, if circumferential seals are provided at both ends of the developing roller and spacers are provided outside these circumferential seals, the axial length of the developing roller becomes long. When the axial length of the developing roller becomes long, the developing roller bends, and even if the accuracy of the developing gap is improved with a sheet-like spacer, the developing gap fluctuates and the developing gap accuracy decreases. Therefore, if the spacer is provided inside the peripheral surface seal, the spacer is contaminated due to toner spillage, and similarly, the development gap fluctuates and the accuracy of the development gap decreases.

  The present invention has been made in view of such circumstances, and its object is to shorten the axial length of the developing roller while reducing the developing gap as much as possible to obtain high image quality, and to provide a spacer. It is an object of the present invention to provide an image forming apparatus that can suppress the contamination and maintain the development gap with high accuracy.

  In order to solve the above-mentioned problems, the invention of claim 1 is characterized in that an image carrier and a toner conveying surface are provided to face the image carrier with a predetermined development gap therebetween, and the image carrier is provided with toner. In an image forming apparatus for performing non-contact jumping development, the image forming apparatus includes at least a developing roller that conveys the toner and a gap adjusting member that is provided at both ends of the developing roller and sets the developing gap by contacting the image carrier. The gap adjusting member is composed of a sheet-like spacer, and circumferential seals for preventing toner from spilling from both ends of the developing roller are provided at both ends of the developing roller and the spacer of the developing roller, respectively. It is characterized in that it is provided so as to be overlapped on the spacer in the inner part.

The invention according to claim 2 is characterized in that the peripheral surface seal is also used as a cleaning member for cleaning the spacer.
Furthermore, the invention of claim 3 is characterized in that the peripheral surface seal is formed of a raised material.

Furthermore, the invention of claim 4 is provided with a cleaning blade for cleaning the image carrier, and the width of the cleaning blade is set larger than the distance between the outer edges of the spacers at both ends of the developing roller. It is characterized by.
Further, the invention of claim 5 is characterized in that a cleaning member for cleaning the spacer contact portion is provided at a spacer contact portion of the image carrier on which the spacer contacts.

Furthermore, the invention of claim 6 is characterized in that the circumferential seal, the toner, and the charged column of the spacer are
+> Surface seal>Toner>Spacer>-
It is characterized by being set to.

Furthermore, the invention of claim 7 is provided with a charging member for charging the image carrier and a cleaning blade for cleaning the image carrier, and the charging width of the charging member is between the outer edges of the spacers. Is set to be larger than the distance of the peripheral surface seal, the toner, the charged column of the spacer,
+>Toner> Peripheral seal, spacer>-
It is characterized by being set to.

Further, according to an eighth aspect of the present invention, the peripheral surface seal is overlapped from an inner edge of the spacer, and includes a charging member for charging the image carrier, and a cleaning blade for cleaning the image carrier. The charging width of the charging member is set to be smaller than the distance between the inner edges of the spacer and larger than the distance between the inner edges of the peripheral seal, and the peripheral seal, the toner, and the spacer The charged column is
+> Peripheral seal, spacer>Toner> −
It is characterized by being set to.

  According to the image forming apparatus of the present invention configured as described above, since the peripheral surface seal is overlapped on the outer peripheral surface of the sheet-like spacer fixed to both end portions of the developing roller, both end portions of the developing roller The axial length of the developing roller can be shortened as compared with the case where the outer peripheral surface is provided with a peripheral surface seal and spacers are provided at both ends of the developing roller outside the peripheral surface seal. Therefore, the amount of bending of the developing roller can be reduced.

  As a result, the fluctuation of the developing gap due to the bending of the developing roller is suppressed, and the developing gap can be maintained with high accuracy. In addition, when the development gap is set small by using a sheet-like spacer for the purpose of improving the image quality, the influence on the image quality due to the development gap variation can be effectively suppressed.

In particular, according to the second aspect of the invention, since the peripheral surface seal also serves as a cleaning member for the spacer, even if foreign matters such as toner adhere to the spacer and are contaminated, the foreign matter is removed by the peripheral surface seal. Then, the dirt can be wiped off. Accordingly, the outer peripheral surface of the spacer is a smooth and clean surface, so that the development gap can always be maintained with high accuracy, and a uniform predetermined development gap can always be maintained. In addition, since there is no need to provide a dedicated cleaning member for the spacer, the number of parts can be reduced.
According to the invention of claim 3, the use of the raised material for the peripheral surface seal can further improve the cleaning effect on the spacer.

  According to a fourth aspect of the present invention, the width of the cleaning blade of the image carrier is set larger than the distance between the outer edges of the spacers at both ends of the developing roller, and the cleaning blade is disposed at the spacer contact portion of the image carrier. Therefore, the spacer contact portion of the image carrier can be constantly cleaned. According to the fifth aspect of the present invention, since the cleaning member is disposed at the spacer contact portion of the image carrier, the spacer contact portion of the image carrier can be constantly cleaned. Therefore, in the inventions according to claims 4 and 5, when the image carrier and the spacer come into contact with each other, the space between the image carrier and the spacer can always be kept clean without contamination of foreign matters such as toner. This also makes it possible to always maintain the development gap with high accuracy and to always maintain a uniform predetermined development gap. In the invention of claim 4, since the image carrier cleaning blade is used, the number of parts can be reduced.

Further, according to the invention of claim 6, in the invention of claim 4 or 5, the circumferential row seal, the toner, and the charged column of the spacer are
+> Surface seal>Toner>Spacer>-
Therefore, it is possible to prevent the charge amount of the toner scattered in the air and adhering to the spacer from increasing. As a result, the toner can be easily cleaned from the spacer.

Further, according to the invention of claim 7, the charging width of the charging member is set to be larger than the distance between the outer edges of the spacer, and the peripheral surface seal, the toner, and the charging column of the spacer are
+>Toner> Peripheral seal, spacer>-
Therefore, the toner adhering to the spacer can positively charge the toner that has entered between the spacer and the peripheral seal by, for example, passing through the peripheral seal because the toner particle size is too small. . The toner on the spacer can be developed on the image carrier by negatively charging the spacer contact portion of the image carrier with the charging member. Therefore, the toner on the spacer that cannot be cleaned by the peripheral seal can be removed, and the spacer can be reliably cleaned. Further, the toner developed on the image carrier can be removed and collected by a cleaning blade.

Further, according to the invention of claim 8, the charging width of the charging member is set smaller than the distance between the inner edges of the spacer and larger than the distance between the inner edges of the peripheral seal, and the peripheral seal, toner, spacer The charged column
+> Peripheral seal, spacer>Toner> −
Therefore, the toner adhering to the spacer can negatively charge the toner that has entered between the spacer and the peripheral seal, for example, by passing through the peripheral seal because the toner particle size is too small. . By not charging the spacer contact portion of the image carrier, the toner on the spacer can be developed on the image carrier by setting the potential of the toner to the plus side of the potential of the developing roller. Therefore, the toner on the spacer that cannot be cleaned by the peripheral seal can be removed, and the spacer can be reliably cleaned. Further, the toner developed on the image carrier can be removed and collected by a cleaning blade.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram schematically illustrating an example of an embodiment of an image forming apparatus according to the present invention. In the claims and the specification, the inner side indicates the center side of the developing roller, and the outer side indicates both end sides of the developing roller.

  As shown in FIG. 1, an image forming apparatus 1 of this example includes a photosensitive member 2 that is an image carrier on which an electrostatic latent image and a toner image are formed, a charging device 3 that charges the photosensitive member 2, and a photosensitive member 2. The developing device 4 that develops the electrostatic latent image formed thereon with non-magnetic one-component toner (hereinafter also simply referred to as toner), and the primary transfer that primarily transfers the toner image developed by the developing device 4 to the intermediate transfer member 5 A device 6 and a cleaning device 7 for removing and collecting the toner remaining on the photoreceptor 2 after the primary transfer are provided.

  Then, an electrostatic latent image is formed by an exposure device (not shown) on the photosensitive member 2 whose image forming area is uniformly charged by the charging roller 3a of the charging device 3, and the electrostatic latent image on the photosensitive member 2 is developed. The toner image is formed by developing with the non-magnetic one-component toner conveyed by the developing roller 4a of the apparatus 4. The toner image on the photoreceptor 2 is primarily transferred to the intermediate transfer member 5 by the transfer roller 6a of the primary transfer device 6 to form a transfer image. Although not shown, the transfer image on the intermediate transfer member 5 is transferred to a recording medium such as paper by a secondary transfer device, and the transfer image on the recording medium is fixed by a fixing device to form an image. The toner remaining on the photoreceptor 2 after the primary transfer is removed and collected by the cleaning blade 7a of the cleaning device 7.

  The developing device 4 includes a developing roller 4a that conveys toner to the photosensitive member 2, a supply roller 4b that is pressed against the developing roller 4a and supplies toner, and a developing case 4c. A roller 4a and a supply roller 4b are accommodated. Then, the nonmagnetic one-component toner accommodated in the developing case 4c is conveyed toward the supply roller 4b while being agitated by a toner agitating / conveying member (not shown), and is further supplied to the developing roller 4a by the supply roller 4b. The toner on the developing roller 4a is regulated and thinned by a regulating blade (not shown), and this thin layer of toner is conveyed toward the photoreceptor 2 by the developing roller 4a.

  As shown in FIG. 2A, the developing roller 4a has a toner transport surface 4d formed at the center thereof, and toner non-transport surfaces formed at both ends (FIG. 2A, FIG. 2A). (B) shows only the toner non-conveying surface 4e on the left end side in the drawing of the developing roller 4a, but the toner non-conveying surface on the right end side is also provided in the same manner although it is symmetrical.)

  A sheet-like spacer 8 is fixed to the toner non-conveying surface 4e (similarly, the same spacer is also fixed to the toner non-conveying surface on the right end side of the developing roller 4a. Hereinafter, for convenience of explanation, development is performed. The right end side of the roller 4a will be described with the same reference numerals as the left end side. As the sheet-like spacer 8, a tape or a tube made of plastic or rubber such as fluororesin, polyester, polyolefin, polyimide, epoxy, acetate, silicone, acrylic, rubber, or the like can be used. In that case, an insulator is preferable. In particular, the spacer 8 is preferably an adhesive tape or a seamless heat shrinkable tube. As shown in FIG. 2B, these spacers 8 are pressed against the image non-carrying surface 2 a of the photoreceptor 2, so that the toner conveying surface 4 d of the developing roller 4 a is brought into contact with the image carrying surface 2 b of the photoreceptor 2. On the other hand, they are opposed to each other with a predetermined development gap g.

  The developing gap g is adjusted to a desired size by appropriately selecting the thickness of the spacer 8. As a result, the developing device 4 performs non-magnetic one-component developer non-contact jumping development using toner which is a non-magnetic one-component developer.

  A peripheral surface seal 9 is provided on the toner non-conveying surface 4 e and the outer peripheral surface of the spacer 8. The peripheral surface seal 9 covers the toner non-conveying surface 4 e inside the spacer 8 and the outer peripheral surface and side surfaces of the spacer 8. Is provided. That is, the peripheral surface seal 9 is provided on the outer peripheral surface of the spacer 8 so as to overlap from the inside of the spacer 8. A conventionally known sealing member can be used as the peripheral surface seal 9, and it is particularly preferable to use a raised material. The peripheral surface seal 9 prevents the toner on the toner transport surface 4d from leaking toward the left end of the developing roller 4a (similar peripheral surface seals 9 are symmetrical on the right end side of the developing roller 4a). The leakage of the toner toward the right end of the developing roller 4a is similarly prevented). Thus, the peripheral surface seal 9 also serves as a cleaning member for the spacer 8 by overlapping the outer peripheral surface of the spacer 8.

  As shown in FIG. 2B, the cleaning blade 7a extends in a direction parallel to the axial direction of the photosensitive member 2, and the width of the cleaning blade 7a (the length in the direction parallel to the axial direction of the photosensitive member 2). Is set to be larger than the length between the outer edges 8 a of the left and right spacers 8. In this case, the left and right ends of the cleaning blade 7 a are located outside the outer edges 8 a of the left and right spacers 8, respectively. Therefore, the cleaning blade 7 a is located at the spacer contact portion 2 c of the photoreceptor 2.

Further, the circumferential row seal 9, the toner, and the charged column of the spacer 8 are:
+> Surface seal 9>Toner> Spacer 8>-
Is set to This electrification row is when the two members are rubbed together
+> Member charged positive (+)> Member charged negative (-)>-
Represented as:

  According to the image forming apparatus 1 of this example configured as described above, the peripheral surface seal 9 is overlapped on the outer peripheral surface of the sheet-like spacer 8 fixed to both ends of the developing roller 4a. Compared with the case where the peripheral seal 9 is provided on the outer peripheral surface of both ends of the roller 4a and the spacer 8 is provided on both ends of the developing roller 4a outside the peripheral seal 9, the length of the developing roller 4a in the axial direction is increased. Can be shortened. Therefore, the amount of bending of the developing roller 4a can be reduced.

As a result, the fluctuation of the developing gap g due to the bending of the developing roller 4a is suppressed, and the developing gap g can be maintained with high accuracy. In addition, when the development gap g is set small by using the sheet-like spacer 8 for the purpose of improving the image quality, the influence on the image quality due to the fluctuation of the development gap g can be effectively suppressed.
In particular, it is preferable to use a heat shrinkable tube as the spacer 8. 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.

  Further, since the peripheral surface seal 9 overlaps with the spacer 8, the peripheral surface seal 9 also serves as a cleaning member for the spacer 8. Foreign matter can be removed and the dirt can be wiped off. Accordingly, since the outer peripheral surface of the spacer 8 is a smooth and clean surface, the development gap g can be always maintained with high accuracy, and a uniform predetermined development gap can be always maintained. In particular, by using a brushed material for the peripheral surface seal 9, the cleaning effect on the spacer 8 can be further improved.

  Further, the width of the cleaning blade 7a is set to be larger than the distance between the outer edges 8a of the left and right spacers 8, and the cleaning blade 7a is positioned at the spacer contact portion 2c of the photoreceptor 2. The contact portion 2c can be constantly cleaned. Therefore, when the photosensitive member 2 and the spacer 8 come into contact with each other, the space between the photosensitive member 2 and the spacer 8 can always be kept clean without contamination of foreign matters such as toner. Also by this, the development gap g can always be maintained with high accuracy, and a uniform predetermined development gap can always be maintained.

Further, when the charge amount of the toner scattered in the air and adhering to the spacer 8 is increased, the mirror image force is increased and the toner cannot be cleaned from the spacer 8 in some cases. Therefore, the circumferential row seal 9, the toner, and the charged column of the spacer 8 are
+> Surface seal 9>Toner> Spacer 8>-
Therefore, it is possible to prevent the toner charge amount from increasing. As a result, the toner can be easily cleaned from the spacer 8.

FIG. 3 is a view similar to FIG. 2B, showing another example of the embodiment of the image forming apparatus of the present invention.
In the example shown in FIG. 2B, the cleaning blade 7a of the photosensitive member 2 extends to the spacer contact portion 2c of the photosensitive member 2, but as shown in FIG. In 1, instead of the cleaning blade 7 a of the photoconductor 2, a dedicated cleaning member 10 for cleaning the spacer contact portion 2 c of the photoconductor 2 is provided. Since the spacer contact portion 2c of the photosensitive member 2 is outside the development region, it is not necessary to clean a large amount of residual toner unlike the cleaning blade 7a. Therefore, the cleaning member 10 is a member such as a brushed material or a sponge. Can be used.
Other configurations and operational effects of this example are the same as those of the example shown in FIGS. 2 (a) and 2 (b).

FIG. 4 is a view similar to FIG. 2B, showing still another example of the embodiment of the image forming apparatus of the present invention.
In the example shown in FIG. 2 described above, the charging width of the charging roller 3a for charging the photosensitive member 2 is set to the image forming area width of the photosensitive member 2, but as shown in FIG. 1, the charging width of the charging roller 3 a is set to be larger than the distance between the outer edges 8 a of the left and right spacers 8, and the charging roller 3 a is positioned at the spacer contact portion 2 c of the photoreceptor 2. Thereby, the spacer contact portion 2c of the photosensitive member 2 can be charged by the charging roller 3a. In that case, the charging roller 3a causes the photoreceptor 2 including the spacer contact portion 2c to be negatively charged.
Further, in this example, the charged column of the peripheral seal 9, the toner, and the spacer 8 is
+>Toner> Peripheral seal 9, spacer 8>-
Is set to
The other configuration of this example is the same as the example shown in FIG.

By the way, the toner attached to the spacer 8 may not be able to clean the toner on the spacer 8 with the peripheral surface seal 9 because, for example, the toner particle size is too small to pass through the peripheral surface seal 9. However, in this example, since the peripheral seal 9, the toner, and the charge column of the spacer 8 are set as described above, the toner that has entered between the spacer 8 and the peripheral seal 9 can be positively charged. it can. The toner on the spacer 8 can be developed on the photosensitive member 2 by negatively charging the spacer contact portion 2c of the photosensitive member 2 with the charging roller 3a. Accordingly, the toner on the spacer 8 that cannot be cleaned by the peripheral seal 9 can be removed, and the spacer 8 can be reliably cleaned. The toner developed on the photoreceptor 2 is removed and collected by the cleaning blade 7a.
Other functions and effects of this example are the same as those of the example shown in FIG.

FIG. 5 is a view similar to FIG. 2B, showing still another example of the embodiment of the image forming apparatus of the present invention.
In the example shown in FIG. 4, the charging roller 3a is positioned at the spacer contact portion 2c of the photosensitive member 2. However, in the image forming apparatus 1 of this example, as shown in FIG. 5, the charging roller 3a is charged. The width is set smaller than the distance between the inner edges 8 b of the left and right spacers 8 and larger than the distance between the inner edges 9 a of the left and right peripheral seals 9, and the charging roller 3 a is attached to the spacer contact portion 2 c of the photoreceptor 2. Since it is not positioned, the spacer contact portion 2c of the photoreceptor 2 is not charged.

Further, in this example, the charged column of the peripheral seal 9, the toner, and the spacer 8 is
+> Peripheral seal 9, spacer 8>Toner> −
Is set to
The other configuration of this example is the same as the example shown in FIG.

  In this example, since the charging row of the peripheral surface seal 9, the toner, and the spacer 8 is set as described above, the toner that has entered between the spacer 8 and the peripheral surface seal 9 can be negatively charged. Then, by not charging the spacer contact portion 2c of the photoconductor 2, the toner on the spacer 8 can be developed on the photoconductor 2 by setting the potential of the toner to the plus side of the potential of the developing roller. Accordingly, the toner on the spacer 8 that cannot be cleaned by the peripheral seal 9 can be removed, and the spacer 8 can be reliably cleaned. The toner developed on the photoreceptor 2 is removed and collected by the cleaning blade 7a.

Further, by setting the charging width of the charging roller 3a to be larger than the distance between the inner edges 9a of the left and right peripheral surface seals 9, the potential at the peripheral surface seal facing portion of the photoreceptor 2 is increased negatively, and the scattered toner However, it can be made difficult to come close to the peripheral surface seal facing portion of the photoreceptor 2.
Other functions and effects of this example are the same as those of the example shown in FIG.

Next, examples of the present invention will be described.
Example 1
In Example 1, a printer LP-9000C manufactured by Seiko Epson Corporation similar to the image forming apparatus shown in FIG. 1 was used as the image forming apparatus. At this time, a tape-like spacer 8 was wound around the toner non-conveying surface of the LP-9000C developing roller 4a as shown in FIG. For the spacer 8, Kapton tape (manufactured by Toray DuPont) was used. A peripheral surface seal 9 is provided so as to overlap the spacer 8 on the non-conveying surface of the spacer 8 and the developing roller 4a. A urethane material was used for the peripheral surface seal 9. The cleaning blade 7a was made of the same material as the LP-9000C cleaning blade, and its width was set larger than the distance between the outer edges 8a of the left and right spacers 8. By using LP-9000C toner, the circumferential seal 9, the toner, and the charged column of the spacer 8 can be
+> Surface seal 9>Toner> Spacer 8>-
Set to. In this charging row, two of the peripheral seal 9, toner, and spacer 8 are selected in sequence, and these two are rubbed together to determine whether the surface potential meter is positively charged or negatively charged. Judgment was made by measuring.

  By overlapping the peripheral surface seal 9 with the spacer 8, the axial length of the developing roller 4a is shortened, and the width of contact of the developing roller 4a with the photosensitive member 2 can be shortened, so that the deflection of the developing roller is reduced. As a result of printing 6000 sheets with LP-9000C, it was confirmed that there was almost no stain on the spacer 8 and this stain could be effectively prevented. As a result, it has been found that the development gap g can always be maintained more accurately.

(Example 2)
In Example 2, an acetate film was used for the spacer 8 wound around the toner non-conveying surface of the LP-9000C developing roller 4a as shown in FIG. Further, the width of the charging roller 3 a is set smaller than the distance between the inner edges 8 b of the left and right spacers 8 and larger than the distance between the inner edges 9 a of the left and right peripheral seals 9. By using LP-9000C toner, the peripheral row 9, the toner, and the charged column of the spacer 8 can be
+> Surface seal 9> Spacer 8>Toner>-
Set to. Others are the same as the first embodiment.
In Example 2, the same thing as Example 1 was confirmed.

(Example 3)
In Example 3, as shown in FIG. 8, the peripheral surface seal 9 is overlapped on the spacer 8 wound around the toner non-conveying surface of the developing roller 4 a of LP-9000C. A polyethylene sponge was used for the peripheral seal 9. Further, the width of the charging roller 3a was set larger than the distance between the outer edges 8a of the left and right spacers 8. By using LP-9000C toner, the circumferential seal 9, the toner, and the charged column of the spacer 8 can be
+>Toner> peripheral seal 9> spacer 8> −
Set to. Others are the same as the first embodiment.
In this Example 3, the same thing as Example 1 was confirmed.

  The image forming apparatus according to the present invention is an electrophotographic image forming apparatus such as an electrophotographic, electrostatic copying machine, printer, or facsimile, and the developing roller is disposed with a predetermined developing gap with respect to the image carrier. It can be suitably used for an image forming apparatus that forms an image by developing an electrostatic latent image on an image carrier using a non-magnetic one-component toner by a contact jumping development method.

1 is a diagram schematically illustrating an example of an embodiment of an image forming apparatus according to the present invention. FIG. 1 schematically shows a state in which a spacer and a peripheral seal are provided at one end of a developing roller of the image forming apparatus of the example shown in FIG. 1, and FIG. b) is a diagram showing the relationship between the developing roller, the spacer, the peripheral surface seal, and the cleaning blade. FIG. 6 is a view similar to FIG. 2B, showing another example of the embodiment of the image forming apparatus of the present invention. It is a figure similar to FIG.2 (b) which shows the other example of embodiment of the image forming apparatus of this invention. It is a figure similar to FIG.2 (b) which shows the other example of embodiment of the image forming apparatus of this invention. It is a figure which shows typically the image forming apparatus used for Example 1 of this invention. It is a figure which shows typically the image forming apparatus used for Example 2 of this invention. It is a figure which shows typically the image forming apparatus used for Example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Photoconductor (image carrier), 3 ... Charging device, 3a ... Charging roller, 4 ... Developing device, 4a ... Developing roller, 4b ... Supply roller, 7 ... Cleaning device, 7a ... Cleaning blade , 8 ... spacer, 8 a ... outer edge of the spacer, 8 b ... inner edge of the spacer, 9 ... peripheral seal, 9 a ... inner edge of the peripheral seal, 10 ... cleaning member

Claims (8)

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 roller for conveying toner to the image carrier; and provided at both ends of the developing roller. An image forming apparatus for performing non-contact jumping development, comprising at least a gap adjusting member that sets the development gap by contacting the image carrier.
The gap adjusting member is composed of a sheet-like spacer,
A peripheral surface seal for preventing toner from spilling from both ends of the developing roller is provided on both ends of the spacer and the developing roller so as to be overlapped on the spacer. An image forming apparatus. The image forming apparatus according to claim 1, wherein the peripheral surface seal is also used as a cleaning member for cleaning the spacer. The image forming apparatus according to claim 2, wherein the peripheral surface seal is formed of a raised material. A cleaning blade for cleaning the image carrier,
4. The image forming apparatus according to claim 1, wherein a width of the cleaning blade is set larger than a distance between outer edges of the spacers at both ends of the developing roller. 4. The image forming apparatus according to claim 1, wherein a cleaning member for cleaning the spacer contact portion is provided at a spacer contact portion with which the spacer of the image carrier contacts. . The circumferential seal, the toner, and the charged column of the spacer are
+> Surface seal>Toner>Spacer>-
The image forming apparatus according to claim 4, wherein the image forming apparatus is set as follows. A charging member for charging the image carrier and a cleaning blade for cleaning the image carrier;
The charging width of the charging member is set to be larger than the distance between the outer edges of the spacer;
The circumferential seal, the toner, and the charged column of the spacer are
+>Toner> Peripheral seal, spacer>-
4. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured as follows. The circumferential seal is overlapped from the inner edge of the spacer;
A charging member for charging the image carrier and a cleaning blade for cleaning the image carrier;
The charging width of the charging member is set to be smaller than the distance between the inner edges of the spacer and larger than the distance between the inner edges of the peripheral seal,
The circumferential seal, the toner, and the charged column of the spacer are
+> Peripheral seal, spacer>Toner> −
4. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured as follows.

Images